Science.gov

Sample records for affecting radionuclide transport

  1. Conditions and processes affecting radionuclide transport

    USGS Publications Warehouse

    Simmons, Ardyth M.; Neymark, Leonid A.

    2012-01-01

    Understanding of unsaturated-zone transport is based on laboratory and field-scale experiments. Fractures provide advective transport pathways. Sorption and matrix diffusion may contribute to retardation of radionuclides. Conversely, sorption onto mobile colloids may enhance radionuclide transport.

  2. Geochemical factors affecting radionuclide transport through near and far fields at a Low-Level Waste Disposal Site

    SciTech Connect

    Kaplan, D.I.; Seme, R.J.; Piepkho, M.G.

    1995-03-01

    The concentration of low-level waste (LLW) contaminants in groundwater is determined by the amount of contaminant present in the solid waste, rate of release from the waste and surrounding barriers, and a number of geochemical processes including adsorption, desorption, diffusion, precipitation, and dissolution. To accurately predict radionuclide transport through the subsurface, it is essential that the important geochemical processes affecting radionuclide transport be identified and, perhaps more importantly, accurately quantified and described in a mathematically defensible manner.

  3. EBS Radionuclide Transport Abstraction

    SciTech Connect

    J. Prouty

    2006-07-14

    The purpose of this report is to develop and analyze the engineered barrier system (EBS) radionuclide transport abstraction model, consistent with Level I and Level II model validation, as identified in Technical Work Plan for: Near-Field Environment and Transport: Engineered Barrier System: Radionuclide Transport Abstraction Model Report Integration (BSC 2005 [DIRS 173617]). The EBS radionuclide transport abstraction (or EBS RT Abstraction) is the conceptual model used in the total system performance assessment (TSPA) to determine the rate of radionuclide releases from the EBS to the unsaturated zone (UZ). The EBS RT Abstraction conceptual model consists of two main components: a flow model and a transport model. Both models are developed mathematically from first principles in order to show explicitly what assumptions, simplifications, and approximations are incorporated into the models used in the TSPA. The flow model defines the pathways for water flow in the EBS and specifies how the flow rate is computed in each pathway. Input to this model includes the seepage flux into a drift. The seepage flux is potentially split by the drip shield, with some (or all) of the flux being diverted by the drip shield and some passing through breaches in the drip shield that might result from corrosion or seismic damage. The flux through drip shield breaches is potentially split by the waste package, with some (or all) of the flux being diverted by the waste package and some passing through waste package breaches that might result from corrosion or seismic damage. Neither the drip shield nor the waste package survives an igneous intrusion, so the flux splitting submodel is not used in the igneous scenario class. The flow model is validated in an independent model validation technical review. The drip shield and waste package flux splitting algorithms are developed and validated using experimental data. The transport model considers advective transport and diffusive transport

  4. EBS Radionuclide Transport Abstraction

    SciTech Connect

    R. Schreiner

    2001-06-27

    The purpose of this work is to develop the Engineered Barrier System (EBS) radionuclide transport abstraction model, as directed by a written development plan (CRWMS M&O 1999a). This abstraction is the conceptual model that will be used to determine the rate of release of radionuclides from the EBS to the unsaturated zone (UZ) in the total system performance assessment-license application (TSPA-LA). In particular, this model will be used to quantify the time-dependent radionuclide releases from a failed waste package (WP) and their subsequent transport through the EBS to the emplacement drift wall/UZ interface. The development of this conceptual model will allow Performance Assessment Operations (PAO) and its Engineered Barrier Performance Department to provide a more detailed and complete EBS flow and transport abstraction. The results from this conceptual model will allow PA0 to address portions of the key technical issues (KTIs) presented in three NRC Issue Resolution Status Reports (IRSRs): (1) the Evolution of the Near-Field Environment (ENFE), Revision 2 (NRC 1999a), (2) the Container Life and Source Term (CLST), Revision 2 (NRC 1999b), and (3) the Thermal Effects on Flow (TEF), Revision 1 (NRC 1998). The conceptual model for flow and transport in the EBS will be referred to as the ''EBS RT Abstraction'' in this analysis/modeling report (AMR). The scope of this abstraction and report is limited to flow and transport processes. More specifically, this AMR does not discuss elements of the TSPA-SR and TSPA-LA that relate to the EBS but are discussed in other AMRs. These elements include corrosion processes, radionuclide solubility limits, waste form dissolution rates and concentrations of colloidal particles that are generally represented as boundary conditions or input parameters for the EBS RT Abstraction. In effect, this AMR provides the algorithms for transporting radionuclides using the flow geometry and radionuclide concentrations determined by other

  5. EBS Radionuclide Transport Abstraction

    SciTech Connect

    J.D. Schreiber

    2005-08-25

    The purpose of this report is to develop and analyze the engineered barrier system (EBS) radionuclide transport abstraction model, consistent with Level I and Level II model validation, as identified in ''Technical Work Plan for: Near-Field Environment and Transport: Engineered Barrier System: Radionuclide Transport Abstraction Model Report Integration'' (BSC 2005 [DIRS 173617]). The EBS radionuclide transport abstraction (or EBS RT Abstraction) is the conceptual model used in the total system performance assessment for the license application (TSPA-LA) to determine the rate of radionuclide releases from the EBS to the unsaturated zone (UZ). The EBS RT Abstraction conceptual model consists of two main components: a flow model and a transport model. Both models are developed mathematically from first principles in order to show explicitly what assumptions, simplifications, and approximations are incorporated into the models used in the TSPA-LA. The flow model defines the pathways for water flow in the EBS and specifies how the flow rate is computed in each pathway. Input to this model includes the seepage flux into a drift. The seepage flux is potentially split by the drip shield, with some (or all) of the flux being diverted by the drip shield and some passing through breaches in the drip shield that might result from corrosion or seismic damage. The flux through drip shield breaches is potentially split by the waste package, with some (or all) of the flux being diverted by the waste package and some passing through waste package breaches that might result from corrosion or seismic damage. Neither the drip shield nor the waste package survives an igneous intrusion, so the flux splitting submodel is not used in the igneous scenario class. The flow model is validated in an independent model validation technical review. The drip shield and waste package flux splitting algorithms are developed and validated using experimental data. The transport model considers

  6. Modeling Radionuclide Transport in Clays

    SciTech Connect

    Zheng, Liange; Li, Lianchong; Rutqvist, Jonny; Liu, Hui -Hai; Birkholzer, Jens

    2012-05-01

    Clay/shale has been considered as potential host rock for geological disposal of high-level nuclear waste throughout the world, because of its low permeability, low diffusion coefficient, high retention capacity for radionuclides, and capability to self-seal fractures induced by tunnel excavation. For example, Callovo-Oxfordian argillites at the Bure site, France (Fouche et al., 2004), Toarcian argillites at the Tournemire site, France (Patriarche et al., 2004), Opalinus Clay at the Mont Terri site, Switzerland (Meier et al., 2000), and Boom clay at the Mol site, Belgium (Barnichon and Volckaert, 2003) have all been under intensive scientific investigation (at both field and laboratory scales) for understanding a variety of rock properties and their relationships to flow and transport processes associated with geological disposal of nuclear waste. Clay/shale formations may be generally classified as indurated or plastic clays (Tsang and Hudson, 2010). The latter (including Boom clay) is a softer material without high cohesion; its deformation is dominantly plastic. During the lifespan of a clay repository, the repository performance is affected by complex thermal, hydrogeological, mechanical, chemical (THMC) processes, such as heat release due to radionuclide decay, multiphase flow, formation of damage zones, radionuclide transport, waste dissolution, and chemical reactions. All these processes are related to each other. An in-depth understanding of these coupled processes is critical for the performance assessment (PA) of the repository. These coupled processes may affect radionuclide transport by changing transport paths (e.g., formation and evolution of excavation damaged zone (EDZ)) and altering flow, mineral, and mechanical properties that are related to radionuclide transport. While radionuclide transport in clay formation has been studied using laboratory tests (e,g, Appelo et al. 2010, Garcia-Gutierrez et al., 2008, Maes et al., 2008), short-term field

  7. Structure and function of subsurface microbial communities affecting radionuclide transport and bioimmobilization

    SciTech Connect

    Kostka, Joel E.; Prakash, Om; Green, Stefan J.; Akob, Denise; Jasrotia, Puja; Kerkhof, Lee; Chin, Kuk-Jeong; Sheth, Mili; Keller, Martin; Venkateswaran, Amudhan; Elkins, James G.; Stucki, Joseph W.

    2012-05-01

    Our objectives were to: 1) isolate and characterize novel anaerobic prokaryotes from subsurface environments exposed to high levels of mixed contaminants (U(VI), nitrate, sulfate), 2) elucidate the diversity and distribution of metabolically active metal- and nitrate-reducing prokaryotes in subsurface sediments, and 3) determine the biotic and abiotic mechanisms linking electron transport processes (nitrate, Fe(III), and sulfate reduction) to radionuclide reduction and immobilization. Mechanisms of electron transport and U(VI) transformation were examined under near in situ conditions in sediment microcosms and in field investigations. Field sampling was conducted at the Oak Ridge Field Research Center (ORFRC), in Oak Ridge, Tennessee. The ORFRC subsurface is exposed to mixed contamination predominated by uranium and nitrate. In short, we effectively addressed all 3 stated objectives of the project. In particular, we isolated and characterized a large number of novel anaerobes with a high bioremediation potential that can be used as model organisms, and we are now able to quantify the function of subsurface sedimentary microbial communities in situ using state-of-the-art gene expression methods (molecular proxies).

  8. STRUCTURE AND FUNCTION OF SUBSURFACE MICROBIAL COMMUNITIES AFFECTING RADIONUCLIDE TRANSPORT AND BIOIMMOBILIZATION

    SciTech Connect

    Joel E. Kostka; Lee Kerkhof; Kuk-Jeong Chin; Martin Keller; Joseph W. Stucki

    2011-06-15

    The objectives of this project were to: (1) isolate and characterize novel anaerobic prokaryotes from subsurface environments exposed to high levels of mixed contaminants (U(VI), nitrate, sulfate), (2) elucidate the diversity and distribution of metabolically active metal- and nitrate-reducing prokaryotes in subsurface sediments, and (3) determine the biotic and abiotic mechanisms linking electron transport processes (nitrate, Fe(III), and sulfate reduction) to radionuclide reduction and immobilization. Mechanisms of electron transport and U(VI) transformation were examined under near in situ conditions in sediment microcosms and in field investigations at the Oak Ridge Field Research Center (ORFRC), in Oak Ridge, Tennessee, where the subsurface is exposed to mixed contamination predominated by uranium and nitrate. A total of 20 publications (16 published or 'in press' and 4 in review), 10 invited talks, and 43 contributed seminars/ meeting presentations were completed during the past four years of the project. PI Kostka served on one proposal review panel each year for the U.S. DOE Office of Science during the four year project period. The PI leveraged funds from the state of Florida to purchase new instrumentation that aided the project. Support was also leveraged by the PI from the Joint Genome Institute in the form of two successful proposals for genome sequencing. Draft genomes are now available for two novel species isolated during our studies and 5 more genomes are in the pipeline. We effectively addressed each of the three project objectives and research highlights are provided. Task I - Isolation and characterization of novel anaerobes: (1) A wide range of pure cultures of metal-reducing bacteria, sulfate-reducing bacteria, and denitrifying bacteria (32 strains) were isolated from subsurface sediments of the Oak Ridge Field Research Center (ORFRC), where the subsurface is exposed to mixed contamination of uranium and nitrate. These isolates which are new

  9. Drift-Scale Radionuclide Transport

    SciTech Connect

    J. Houseworth

    2004-09-22

    The purpose of this model report is to document the drift scale radionuclide transport model, taking into account the effects of emplacement drifts on flow and transport in the vicinity of the drift, which are not captured in the mountain-scale unsaturated zone (UZ) flow and transport models ''UZ Flow Models and Submodels'' (BSC 2004 [DIRS 169861]), ''Radionuclide Transport Models Under Ambient Conditions'' (BSC 2004 [DIRS 164500]), and ''Particle Tracking Model and Abstraction of Transport Process'' (BSC 2004 [DIRS 170041]). The drift scale radionuclide transport model is intended to be used as an alternative model for comparison with the engineered barrier system (EBS) radionuclide transport model ''EBS Radionuclide Transport Abstraction'' (BSC 2004 [DIRS 169868]). For that purpose, two alternative models have been developed for drift-scale radionuclide transport. One of the alternative models is a dual continuum flow and transport model called the drift shadow model. The effects of variations in the flow field and fracture-matrix interaction in the vicinity of a waste emplacement drift are investigated through sensitivity studies using the drift shadow model (Houseworth et al. 2003 [DIRS 164394]). In this model, the flow is significantly perturbed (reduced) beneath the waste emplacement drifts. However, comparisons of transport in this perturbed flow field with transport in an unperturbed flow field show similar results if the transport is initiated in the rock matrix. This has led to a second alternative model, called the fracture-matrix partitioning model, that focuses on the partitioning of radionuclide transport between the fractures and matrix upon exiting the waste emplacement drift. The fracture-matrix partitioning model computes the partitioning, between fractures and matrix, of diffusive radionuclide transport from the invert (for drifts without seepage) into the rock water. The invert is the structure constructed in a drift to provide the floor of the

  10. Structure and Function of Subsurface Microbial Communities Affecting Radionuclide Transport and Bio-immobilization

    SciTech Connect

    Kerkhof, Lee

    2013-10-23

    The goal of this research project was to employ a multi-disciplinary team to investigate the DOE-ERSP Field Research Center at Oak Ridge, TN (ORFRC), which contains well-defined subsurface contaminant plumes with contrasting pH and redox conditions. Part of the team would pursue cultivation-independent characterization of the microbial groups catalyzing relevant biogeochemical reactions to gain an understanding of the physiological mechanisms controlling radionuclide immobilization. Other team members would focus on cultivation and physiological characterization of model microorganisms from the site using single cell sorting methods. In order to understand and predict the in situ function of microbial communities, the PIs hope to develop new strategies for cultivation and to couple phylogenetic structure with microbial community function. Specific objectives by the Rutgers group was to discern the active bacteria at the Oak Ridge Research Field Challenge Site: 1. by applying stable isotope probing techniques to enrichment cultures developed from Florida State University; 2. by fingerprinting intact rRNA from groundwater samples obtained along the various flow pathways at ORFRC; and 3. by identifying functional genes for N and S cycling along the flowpaths to aid in detection of active bacteria.

  11. Mathematical simulation of sediment and radionuclide transport in estuaries

    SciTech Connect

    Onishi, Y.; Trent, D.S.

    1982-11-01

    The finite element model LFESCOT (Flow, Energy, Salinity, Sediment and Contaminant Transport Model) was synthesized under this study to simulate radionuclide transport in estuaries to obtain accurate radionuclide distributions which are affected by these factors: time variance, three-dimensional flow, temperature, salinity, and sediments. Because sediment transport and radionuclide adsorption/desorption depend strongly on sizes or types of sediments, FLESCOT simulates sediment and a sediment-sorbed radionuclide for the total of three sediment-size fractions (or sediment types) of both cohesive and noncohesive sediments. It also calculates changes of estuarine bed conditions, including bed elevation changes due to sediment erosion/deposition, and three-dimensional distributions of three bed sediment sizes and sediment-sorbed radionuclides within the bed. Although the model was synthesized for radionuclide transport, it is general enough to also handle other contaminants such as heavy metals, pesticides, or toxic chemicals. The model was checked for its capability for flow, water surface elevation change, salinity, sediment and radionuclide transport under various simple conditions first, confirming the general validity of the model's computational schemes. These tests also revealed that FLESCOT can use large aspect ratios of computational cells, which are necessary in handling long estuarine study areas. After these simple tests, FLESCOT was applied to the Hudson River estuary between Chelsea and the mouth of the river to examine how well the model can predict radionuclide transport through simulating tidally influenced three-dimensional flow, salinity, sediment and radionuclide movements with their interactions.

  12. Drift-Scale Radionuclide Transport

    SciTech Connect

    P.R. Dixon

    2004-02-17

    The purpose of this Model Report is to document two models for drift-scale radionuclide transport. This has been developed in accordance with ''Technical Work Plan for: Performance Assessment Unsaturated Zone'' (Bechtel SAIC Company, LLC (BSC) 2002 [160819]), which includes planning documents for the technical work scope, content, and management of this Model Report in Section 1.15, Work Package AUZM11, ''Drift-Scale Radionuclide Transport.'' The technical work scope for this Model Report calls for development of a process-level model and an abstraction model representing diffusive release from the invert to the rocks, partitioned between fracture and matrix, as compared to the fracture-release approach used in the Site Recommendation. The invert is the structure constructed in a drift to provide the floor of that drift. The plan for validation of the models documented in this Model Report is given in Section I-5 of Attachment I in BSC (2002 [160819]). Note that the model validation presented in Section 7 deviates from the technical work plan (BSC 2002 [160819], Section I-5) in that an independent technical review specifically for model validation has not been conducted, nor publication in a peer-reviewed journal. Model validation presented in Section 7 is based on corroboration with alternative mathematical models, which is also called out by the technical work plan (BSC 2002 [160819], Section I-5), and is sufficient based on the requirements of AP-SIII.10Q for model validation. See Section 7 for additional discussion. The phenomenon of flow and transport in the vicinity of the waste emplacement drift are evaluated in this model report under ambient thermal, chemical, and mechanical conditions. This includes the effects of water diversion around an emplacement drift and the flow and transport behavior expected in a fractured rock below the drift. The reason for a separate assessment of drift-scale transport is that the effects of waste emplacement drifts on flow

  13. RADIONUCLIDE TRANSPORT MODELS UNDER AMBIENT CONDITIONS

    SciTech Connect

    S. Magnuson

    2004-11-01

    The purpose of this model report is to document the unsaturated zone (UZ) radionuclide transport model, which evaluates, by means of three-dimensional numerical models, the transport of radioactive solutes and colloids in the UZ, under ambient conditions, from the repository horizon to the water table at Yucca Mountain, Nevada.

  14. Radionuclides: Accumulation and Transport in Plants.

    PubMed

    Gupta, D K; Chatterjee, S; Datta, S; Voronina, A V; Walther, C

    Application of radioactive elements or radionuclides for anthropogenic use is a widespread phenomenon nowadays. Radionuclides undergo radioactive decays releasing ionizing radiation like gamma ray(s) and/or alpha or beta particles that can displace electrons in the living matter (like in DNA) and disturb its function. Radionuclides are highly hazardous pollutants of considerable impact on the environment, food chain and human health. Cleaning up of the contaminated environment through plants is a promising technology where the rhizosphere may play an important role. Plants belonging to the families of Brassicaceae, Papilionaceae, Caryophyllaceae, Poaceae, and Asteraceae are most important in this respect and offer the largest potential for heavy metal phytoremediation. Plants like Lactuca sativa L., Silybum marianum Gaertn., Centaurea cyanus L., Carthamus tinctorius L., Helianthus annuus and H. tuberosus are also important plants for heavy metal phytoremediation. However, transfer factors (TF) of radionuclide from soil/water to plant ([Radionuclide]plant/[Radionuclide]soil) vary widely in different plants. Rhizosphere, rhizobacteria and varied metal transporters like NRAMP, ZIP families CDF, ATPases (HMAs) family like P1B-ATPases, are involved in the radio-phytoremediation processes. This review will discuss recent advancements and potential application of plants for radionuclide removal from the environment.

  15. Colloid-facilitated radionuclide transport: a regulatory perspective

    NASA Astrophysics Data System (ADS)

    Dam, W. L.; Pickett, D. A.; Codell, R. B.; Nicholson, T. J.

    2001-12-01

    What hydrogeologic-geochemical-microbial conditions and processes affect migration of radionuclides sorbed onto microparticles or native colloid-sized radionuclide particles? The U.S. Nuclear Regulatory Commission (NRC) is responsible for protecting public health, safety, and the environment at numerous nuclear facilities including a potential high-level nuclear waste disposal site. To fulfill these obligations, NRC needs to understand the mechanisms controlling radionuclide release and transport and their importance to performance. The current focus of NRC staff reviews and technical interactions dealing with colloid-facilitated transport relates to the potential nuclear-waste repository at Yucca Mountain, Nevada. NRC staff performed bounding calculations to quantify radionuclide releases available for ground-water transport to potential receptors from a Yucca Mountain repository. Preliminary analyses suggest insignificant doses of plutonium and americium colloids could be derived from spent nuclear fuel. Using surface complexation models, NRC staff found that colloids can potentially lower actinide retardation factors by up to several orders of magnitude. Performance assessment calculations, in which colloidal transport of plutonium and americium was simulated by assuming no sorption or matrix diffusion, indicated no effect of colloids on human dose within the 10,000 year compliance period due largely to long waste-package lifetimes. NRC staff have identified information gaps and developed technical agreements with the U.S. Department of Energy (DOE) to ensure sufficient information will be presented in any potential future Yucca Mountain license application. DOE has agreed to identify which radionuclides could be transported via colloids, incorporate uncertainties in colloid formation, release and transport parameters, and conceptual models, and address the applicability of field data using synthetic microspheres as colloid analogs. NRC is currently

  16. Sediment and radionuclide transport in rivers: radionuclide transport modeling for Cattaraugus and Buttermilk Creeks, New York

    SciTech Connect

    Onishi, Y.; Yabusaki, S.B.; Kincaid, C.T.; Skaggs, R.L.; Walters, W.H.

    1982-12-01

    SERATRA, a transient, two-dimensional (laterally-averaged) computer model of sediment-contaminant transport in rivers, satisfactorily resolved the distribution of sediment and radionuclide concentrations in the Cattaraugus Creek stream system in New York. By modeling the physical processes of advection, diffusion, erosion, deposition, and bed armoring, SERATRA routed three sediment size fractions, including cohesive soils, to simulate three dynamic flow events. In conjunction with the sediment transport, SERATRA computed radionuclide levels in dissolved, suspended sediment, and bed sediment forms for four radionuclides (/sup 137/Cs, /sup 90/Sr, /sup 239/ /sup 240/Pu, and /sup 3/H). By accounting for time-dependent sediment-radionuclide interaction in the water column and bed, SERATA is a physically explicit model of radionuclide fate and migration. Sediment and radionuclide concentrations calculated by SERATA in the Cattaraugus Creek stream system are in reasonable agreement with measured values. SERATRA is in the field performance phase of an extensive testing program designed to establish the utility of the model as a site assessment tool. The model handles not only radionuclides but other contaminants such as pesticides, heavy metals and other toxic chemicals. Now that the model has been applied to four field sites, including the latest study of the Cattaraugus Creek stream system, it is recommended that a final model be validated through comparison of predicted results with field data from a carefully controlled tracer test at a field site. It is also recommended that a detailed laboratory flume be tested to study cohesive sediment transport, deposition, and erosion characteristics. The lack of current understanding of these characteristics is one of the weakest areas hindering the accurate assessment of the migration of radionuclides sorbed by fine sediments of silt and clay.

  17. Model of colloidal transportation of radionuclides by groundwater

    NASA Astrophysics Data System (ADS)

    Malkovsky, V. I.; Yudintsev, S. V.

    2016-09-01

    The transportation of colloidal radionuclides by groundwater was subject to theoretical analysis. The far field of radioactive contamination of the underground environment (liquid waste pumping sites or storage of solidified waste) is dominated by pseudocolloids, i.e., colloidal particles of natural origin contaminated with radionuclides upon contact of groundwater with radioactive materials. Properties of real pseudocolloids were analyzed at sites of radioactive contamination of the underground environment. Based on a probabilistic approach, we developed a mathematical model of pseudocolloid transportation by groundwater, taking into account the difference in size of colloidal particles and the occurrence of nonradioactive natural particles with a similar composition in the groundwater. It is proved that nonuniform dimensions of the particles considerably affect the water transportation rate.

  18. Mathematical Simulation of Sediment and Radionuclide Transport in Surface Waters

    SciTech Connect

    ,

    1981-04-01

    The study objective of "The Mathematical Simulation of Sediment and Radionuclide Transport in Surface Waters" is to synthesize and test radionuclide transport models capable of realistically assessing radionuclide transport in various types of surface water bodies by including the sediment-radionuclide interactions. These interactions include radionuclide adsorption by sediment; desorption from sediment into water; and transport, deposition, and resuspension of sorbed radionuclides controlled by the sediment movements. During FY-1979, the modification of sediment and contaminant (radionuclide) transport model, FETRA, was completed to make it applicable to coastal waters. The model is an unsteady, two-dimensional (longitudinal and lateral) model that consists of three submodels (for sediment, dissolved-contaminant, and particulate-contaminant transport), coupled to include the sediment-contaminant interactions. In estuaries, flow phenomena and consequent sediment and radionuclide migration are often three-dimensional in nature mainly because of nonuniform channel cross-sections, salinity intrusion, and lateral-flow circulation. Thus, an unsteady, three-dimensional radionuclide transport model for estuaries is also being synthesized by combining and modifying a PNL unsteady hydrothermal model and FETRA. These two radionuclide transport models for coastal waters and estuaries will be applied to actual sites to examine the validity of the codes.

  19. Radionuclide Transport Models Under Ambient Conditions

    SciTech Connect

    G. Moridis; Q. Hu

    2000-03-12

    The purpose of this Analysis/Model Report (AMR) is to evaluate (by means of 2-D semianalytical and 3-D numerical models) the transport of radioactive solutes and colloids in the unsaturated zone (UZ) under ambient conditions from the potential repository horizon to the water table at Yucca Mountain (YM), Nevada. This is in accordance with the ''AMR Development Plan U0060, Radionuclide Transport Models Under Ambient Conditions'' (CRWMS M and O 1999a). This AMR supports the UZ Flow and Transport Process Model Report (PMR). This AMR documents the UZ Radionuclide Transport Model (RTM). This model considers: the transport of radionuclides through fractured tuffs; the effects of changes in the intensity and configuration of fracturing from hydrogeologic unit to unit; colloid transport; physical and retardation processes and the effects of perched water. In this AMR they document the capabilities of the UZ RTM, which can describe flow (saturated and/or unsaturated) and transport, and accounts for (a) advection, (b) molecular diffusion, (c) hydrodynamic dispersion (with full 3-D tensorial representation), (d) kinetic or equilibrium physical and/or chemical sorption (linear, Langmuir, Freundlich or combined), (e) first-order linear chemical reaction, (f) radioactive decay and tracking of daughters, (g) colloid filtration (equilibrium, kinetic or combined), and (h) colloid-assisted solute transport. Simulations of transport of radioactive solutes and colloids (incorporating the processes described above) from the repository horizon to the water table are performed to support model development and support studies for Performance Assessment (PA). The input files for these simulations include transport parameters obtained from other AMRs (i.e., CRWMS M and O 1999d, e, f, g, h; 2000a, b, c, d). When not available, the parameter values used are obtained from the literature. The results of the simulations are used to evaluate the transport of radioactive solutes and colloids, and

  20. RADIONUCLIDE TRANSPORT IN FRACTURED TUFF UNDER EPISODIC FLOW CONDITIONS

    SciTech Connect

    O. Hu; Y. Sun; R.P. Ewing

    2005-09-19

    The current conceptual model of radionuclide transport in unsaturated fractured rock includes water movement in fractures, with migration of the entrained radionuclides being retarded by diffusion into and sorption within the rock matrix. Water infiltration and radionuclide transport through low-permeability unsaturated fractured rock are episodic and intermittent in nature, at least at local scales. Under episodic flow conditions, the matrix is constantly imbibing or draining, and this fluctuating wetness both drives two-way advective movement of radionuclides, and forces changes in the matrix diffusivity. This work is intended to examine, both experimentally and numerically, how radionuclide transport under episodic flow conditions is affected by the interacting processes of imbibition and drainage, diffusion, and matrix sorption. Using Topopah Spring welded volcanic tuff, collected from the potential repository geologic unit at Yucca Mountain for storing high-level nuclear waste, we prepared a saw-cut fracture core (length 10.2 cm, diameter 4.4 cm, and fracture aperture 100 {micro}m). The dry core was packed into a flow reactor, flushed with CO{sub 2}, then saturated via slow pumping (0.01 mL/min) of synthetic groundwater. The fractured core was then flushed with air at >97% relative humidity (to simulate in situ unsaturated fractured rock conditions at Yucca Mountain), then the episodic transport experiment was conducted. Episodic flow involved 4 cycles of tracer solution flow within the fracture, followed by flushing with high humidity air. Each flow episode contained a different suite of non-sorbing and sorbing tracers, which included {sup 3}H, ReO{sub 4}{sup -} (a chemical analog for {sup 99}TcO{sub 4}{sup -}), I{sup -} (for {sup 129}I{sup -}), Sr and Cs (for {sup 90}Sr and {sup 137}Cs), plus the radionuclides {sup 235}U, {sup 237}Np, and {sup 241}Pu. These radionuclides span a variety of sorption strengths and represent a large fraction of the radionuclides

  1. Critical review: Radionuclide transport, sediment transport, and water quality mathematical modeling; and radionuclide adsorption/desorption mechanisms

    SciTech Connect

    Onishi, Y.; Serne, R.J.; Arnold, E.M.; Cowan, C.E.; Thompson, F.L.

    1981-01-01

    This report describes the results of a detailed literature review of radionuclide transport models applicable to rivers, estuaries, coastal waters, the Great Lakes, and impoundments. Some representatives sediment transport and water quality models were also reviewed to evaluate if they can be readily adapted to radionuclide transport modeling. The review showed that most available transport models were developed for dissolved radionuclide in rivers. These models include the mechanisms of advection, dispersion, and radionuclide decay. Since the models do not include sediment and radionuclide interactions, they are best suited for simulating short-term radionuclide migration where: (1) radionuclides have small distribution coefficients; (2) sediment concentrations in receiving water bodies are very low. Only 5 of the reviewed models include full sediment and radionuclide interactions: CHMSED developed by Fields; FETRA SERATRA, and TODAM developed by Onishi et al, and a model developed by Shull and Gloyna. The 5 models are applicable to cases where: (1) the distribution coefficient is large; (2) sediment concentrations are high; or (3) long-term migration and accumulation are under consideration. The report also discusses radionuclide absorption/desorption distribution ratios and addresses adsorption/desorption mechanisms and their controlling processes for 25 elements under surface water conditions. These elements are: Am, Sb, C, Ce, Cm, Co, Cr, Cs, Eu, I, Fe, Mn, Np, P, Pu, Pm, Ra, Ru, Sr, Tc, Th, {sup 3}H, U, Zn and Zr.

  2. Radionuclide Transport in Tuff and Carbonate Fractures from Yucca Flat, Nevada Test Site

    SciTech Connect

    Zavarin, M; Johnson, M R; Roberts, S K; Pletcher, R; Rose, T P; Kersting, A B; Eaton, G; Hu, Q; Ramon, E; Walensky, J; Zhao, P

    2006-02-01

    In the Yucca Flat basin of the Nevada Test Site (NTS), 747 shaft and tunnel nuclear detonations were conducted primarily within the tuff confining unit (TCU) or the overlying alluvium. The TCU in the Yucca Flat basin is hypothesized to reduce radionuclide migration to the regional carbonate aquifer (lower carbonate aquifer) due to its wide-spread aerial extent and chemical reactivity. However, shortcuts through the TCU by way of fractures may provide a migration path for radionuclides to the lower carbonate aquifer (LCA). It is, therefore, imperative to understand how radionuclides migrate or are retarded in TCU fractures. Furthermore, understanding the migration behavior of radionuclides once they reach the fractured LCA is important for predicting contaminant transport within the regional aquifer. The work presented in this report includes: (1) information on the radionuclide reactive transport through Yucca Flat TCU fractures (likely to be the primary conduit to the LCA), (2) information on the reactive transport of radionuclides through LCA fractures and (3) data needed to calibrate the fracture flow conceptualization of predictive models. The predictive models are used to define the extent of contamination for the Underground Test Area (UGTA) project. Because of the complex nature of reactive transport in fractures, a stepwise approach to identifying mechanisms controlling radionuclide transport was used. In the first set of TCU experiments, radionuclide transport through simple synthetic parallel-plate fractured tuff cores was examined. In the second, naturally fractured TCU cores were used. For the fractured LCA experiments, both parallel-plate and rough-walled fracture transport experiments were conducted to evaluate how fracture topography affects radionuclide transport. Tuff cores were prepared from archived UE-7az and UE-7ba core obtained from the USGS core library, Mercury, Nevada. Carbonate cores were prepared from archived ER-6-1 core, also obtained

  3. Radionuclide transport behavior in a generic geological radioactive waste repository.

    PubMed

    Bianchi, Marco; Liu, Hui-Hai; Birkholzer, Jens T

    2015-01-01

    We performed numerical simulations of groundwater flow and radionuclide transport to study the influence of several factors, including the ambient hydraulic gradient, groundwater pressure anomalies, and the properties of the excavation damaged zone (EDZ), on the prevailing transport mechanism (i.e., advection or molecular diffusion) in a generic nuclear waste repository within a clay-rich geological formation. By comparing simulation results, we show that the EDZ plays a major role as a preferential flowpath for radionuclide transport. When the EDZ is not taken into account, transport is dominated by molecular diffusion in almost the totality of the simulated domain, and transport velocity is about 40% slower. Modeling results also show that a reduction in hydraulic gradient leads to a greater predominance of diffusive transport, slowing down radionuclide transport by about 30% with respect to a scenario assuming a unit gradient. In addition, inward flow caused by negative pressure anomalies in the clay-rich formation further reduces transport velocity, enhancing the ability of the geological barrier to contain the radioactive waste. On the other hand, local high gradients associated with positive pressure anomalies can speed up radionuclide transport with respect to steady-state flow systems having the same regional hydraulic gradients. Transport behavior was also found to be sensitive to both geometrical and hydrogeological parameters of the EDZ. Results from this work can provide useful knowledge toward correctly assessing the post-closure safety of a geological disposal system.

  4. RADIONUCLIDE DISPERSION RATES BY AEOLIAN, FLUVIAL, AND POROUS MEDIA TRANSPORT

    SciTech Connect

    J. Walton; P. Goodell; C. Brashears; D. French; A. Kelts

    2005-07-11

    Radionuclide transport was measured from high grade uranium ore boulders near the Nopal I Site, Chihuahua, Mexico. High grade uranium ore boulders were left behind after removal of a uranium ore stockpile at the Prior High Grade Stockpile (PHGS). During the 25 years when the boulder was present, radionuclides were released and transported by sheetflow during precipitation events, wind blown resuspension, and infiltration into the unsaturated zone. In this study, one of the boulders was removed, followed by grid sampling of the surrounding area. Measured gamma radiation levels in three dimensions were used to derive separate dispersion rates by the three transport mechanisms.

  5. A model for radionuclide transport in the Cooling Water System

    SciTech Connect

    Kahook, S.D.

    1992-08-01

    A radionuclide transport model developed to assess radiological levels in the K-reactor Cooling Water System (CWS) in the event of an inadvertent process water (PW) leakage to the cooling water (CW) in the heat exchangers (HX) is described. During and following a process water leak, the radionuclide transport model determines the time-dependent release rates of radionuclide from the cooling water system to the environment via evaporation to the atmosphere and blow-down to the Savannah River. The developed model allows for delay times associated with the transport of the cooling water radioactivity through cooling water system components. Additionally, this model simulates the time-dependent behavior of radionuclides levels in various CWS components. The developed model is incorporated into the K-reactor Cooling Tower Activity (KCTA) code. KCTA allows the accident (heat exchanger leak rate) and the cooling tower blow-down and evaporation rates to be described as time-dependent functions. Thus, the postulated leak and the consequence of the assumed leak can be modelled realistically. This model is the first of three models to be ultimately assembled to form a comprehensive Liquid Pathway Activity System (LPAS). LPAS will offer integrated formation, transport, deposition, and release estimates for radionuclides formed in a SRS facility. Process water and river water modules are forthcoming as input and downstream components, respectively, for KCTA.

  6. Simulation of radionuclide transport in U. S. agriculture

    SciTech Connect

    Sharp, R.D.; Baes, C.F. III

    1982-01-01

    Because of the recent concern about the impact of energy technologies on man and related health effects, there has emerged a need for models to calculate or predict the effects of radionuclides on man. A general overview is presented of a model that calculates the ingrowth of radionuclides into man's food chain. The FORTRAN IV computer program TERRA, Transport of Environmentally Released Radionuclides in Agriculture, simulates the build-up of radionuclides in soil, four plant food compartments, in meat and milk from beef, and in the livestock food compartments that cause radionuclide build-up in milk and meat from beef. A large data set of spatially oriented parameters has been developed in conjunction with TERRA. This direct-access data set is called SITE, Specific Information on the Terrestrial Environment, and contains 35 parameters for each of 3525 half-degree longitude-latitude cells which define the lower 48 states. TERRA and SITE are used together as a package for determining radionuclide concentrations in man's food anywhere within the conterminous 48 states due to atmospheric releases.

  7. EOS7R: Radionuclide transport for TOUGH2

    SciTech Connect

    Oldenburg, C.M.; Pruess, K.

    1995-11-01

    EOS7R provides radionuclide transport capability for TOUGH2. EOS7R extends the EOS7 module (water, brine, and optional air) to model water, brine, parent component, daughter component, and optional air and heat. The radionuclide components follow a first-order decay law, and may adsorb onto the solid grains. Volatilization of the decaying components is modeled by Henry`s Law. The decaying components are normally referred to as radionuclides, but they may in fact by any trace components that decay, adsorb, and volatilize. The decay process need not be radioactive decay, but could be any process that follows a first-order decay law, such as biodegradation. EOS7R includes molecular diffusion for all components in gaseous and aqueous phases using a simplified binary diffusion model. When EOS7R is used with standard TOUGH2, transport occurs by advection and molecular diffusion in all phases. When EOS7R is coupled with the dispersion module T2DM, one obtains T2DMR, the radionuclide transport version of T2DM. T2DMR models advection, diffusion, and hydrodynamic dispersion in rectangular two-dimensional regions. Modeling of radionuclide transport requires input parameters specifying the half-life for first-order decay, distribution coefficients for each rock type for adsorption, and inverse Henry`s constants for volatilization. Options can be specified in the input file to model decay in inactive grid blocks and to read from standard EOS7 INCON files. The authors present a number of example problems to demonstrate application and accuracy of TOUGH2/EOS7R. One-dimensional simulation results agree well with analytical solutions. For a two-dimensional salt-dome flow problem, the final distribution of daughter radionuclide component is complicated by the presence of weak recirculation caused by density effects due to salinity.

  8. Assessment of radionuclide vapor-phase transport in unsaturated tuff

    SciTech Connect

    Smith, D.M.; Updegraff, C.D.; Bonano, E.J.; Randall, J.D.

    1986-11-01

    This report describes bounding calculations performed to investigate the possibility of radionuclide migration in a vapor phase associated with the emplacement of high-level waste canister in unsaturated tuff formations. Two potential radionuclide transport mechanisms in the vapor phase were examined: aerosol migration and convection/diffusion of volatile species. The former may have significant impact on the release of radionuclides to the accessible environment as the concentration in the aerosols will be equal to that in the ground water. A conservative analysis of air diffusion in a stagnant liquid film indicated that for all expected repository conditions, aerosol formation is not possible. The migration of volatile species was examined both in the vicinity of a waste canister and outside the thermally disturbed zone. Two-dimensional (radial) and three-dimensional (radial-vertical) coupled heat transfer-gas flow-liquid flow simulations were performed using the TOUGH computer code. The gas flow rate relative to the liquid flow rate predicted from the simulations allowed calculations of mobility ratios due to convection which led to the conclusion that, except for the immediate region near the canister, transport in the liquid phase will be dominant for radionuclides heavier than radon. Near the waste canister, iodine transport may also be important in the vapor phase. Bounding calculations for vertical mobility ratios were carried out as a function of saturation. These calculations are conservative and agree well with the two-dimensional simulations. Based on this analysis, it is clear that vapor-phase transport will not be important for radionuclides such as cesium and heavier species. Vapor transport for iodine may play a role in the overall release scenario depending on the particular repository conditions.

  9. Assessment of hydrologic transport of radionuclides from the Rio Blanco underground nuclear test site, Colorado

    SciTech Connect

    Chapman, J.; Earman, S.; Andricevic, R.

    1996-10-01

    DOE is operating an environmental restoration program to characterize, remediate, and close non-Nevada Test Site locations used for nuclear testing. Evaluation of radionuclide transport by groundwater is part of preliminary risk analysis. These evaluations allow prioritization of test areas in terms of risk, provide a basis for discussions with regulators and the public about future work, and provide a framework for assessing site characterization data needs. The Rio Blanco site in Colorado was the location of the simultaneous detonation of three 30-kiloton nuclear devices. The devices were located 1780, 1899, and 2039 below ground surface in the Fort Union and Mesaverde formations. Although all the bedrock formations at the site are thought to contain water, those below the Green River Formation (below 1000 in depth) are also gas-bearing, and have very low permeabilities. The transport scenario evaluated was the migration of radionuclides from the blast-created cavity through the Fort Union Formation. Transport calculations were performed using the solute flux method, with input based on the limited data available for the site. Model results suggest that radionuclides from the test are contained entirely within the area currently administered by DOE. This modeling was performed to investigate how the uncertainty in various physical parameters affect radionuclide transport at the site, and to serve as a starting point for discussion regarding further investigation; it was not intended to be a definitive simulation of migration pathways or radionuclide concentration values. Given the sparse data, the modeling results may differ significantly from reality. Confidence in transport predictions can be increased by obtaining more site data, including the amount of radionuclides which would have been available for transport (i.e., not trapped in melt glass or vented during gas flow testing), and the hydraulic properties of the formation. 38 refs., 6 figs., 1 tab.

  10. Natural analogue studies of the role of colloids, natural organics and microorganisms on radionuclide transport

    SciTech Connect

    McCarthy, J.F.

    1994-10-01

    Colloids may be important as a geochemical transport mechanism for radionuclides at geological repositories if they are (1) present in the groundwater, (2) stable with respect to both colloidal and chemical stabilities, (3) capable of adsorbing radionuclides, especially if the sorption is irreversible, and (4) mobile in the subsurface. The available evidence from natural analogue and other field studies relevant to these issues is reviewed, as is the potential role of mobile microorganisms ({open_quotes}biocolloids{close_quotes}) on radionuclide migration. Studies have demonstrated that colloids are ubiquitous in groundwater, although colloid concentrations in deep, geochemically stable systems may be too low to affect radionuclide transport. However, even low colloid populations cannot be dismissed as a potential concern because colloids appear to be stable, and many radionuclides that adsorb to colloids are not readily desorbed over long periods. Field studies offer somewhat equivocal evidence concerning colloid mobility and cannot prove or disprove the significance of colloid transport in the far-field environment. Additional research is needed at new sites to properly represent a repository far-field. Performance assessment would benefit from natural analogue studies to examine colloid behavior at sites encompassing a suite of probable groundwater chemistries and that mimic the types of formations selected for radioactive waste repositories.

  11. Radionuclide Transport in Fracture-Granite Interface Zones

    SciTech Connect

    Hu, Q; Mori, A

    2007-09-12

    In situ radionuclide migration experiments, followed by excavation and sample characterization, were conducted in a water-conducting shear zone at the Grimsel Test Site (GTS) in Switzerland to study diffusion paths of radionuclides in fractured granite. In this work, we employed a micro-scale mapping technique that interfaces laser ablation sampling with inductively coupled plasma-mass spectrometry (LA/ICP-MS) to measure the fine-scale (micron-range) distribution of actinides ({sup 234}U, {sup 235}U, and {sup 237}Np) in the fracture-granite interface zones. Long-lived {sup 234}U, {sup 235}U, and {sup 237}Np were detected in flow channels, as well as in the adjacent rock matrix, using the sensitive, feature-based mapping of the LA/ICP-MS technique. The injected sorbing actinides are mainly located within the advective flowing fractures and the immediately adjacent regions. The water-conducting fracture studied in this work is bounded on one side by mylonite and the other by granitic matrix regions. These actinides did not penetrate into the mylonite side as much as the relatively higher-porosity granite matrix, most likely due to the low porosity, hydraulic conductivity, and diffusivity of the fracture wall (a thickness of about 0.4 mm separates the mylonite region from the fracture) and the mylonite region itself. Overall, the maximum penetration depth detected with this technique for the more diffusive {sup 237}Np over the field experimental time scale of about 60 days was about 10 mm in the granitic matrix, illustrating the importance of matrix diffusion in retarding radionuclide transport from the advective fractures. Laboratory tests and numerical modeling of radionuclide diffusion into granitic matrix was conducted to complement and help interpret the field results. Measured apparent diffusivity of multiple tracers in granite provided consistent predictions for radionuclide transport in the fractured granitic rock.

  12. MAGNUM2D. Radionuclide Transport Porous Media

    SciTech Connect

    Langford, D.W.; Baca, R.G.

    1989-03-01

    MAGNUM2D was developed to analyze thermally driven fluid motion in the deep basalts below the Paco Basin at the Westinghouse Hanford Site. Has been used in the Basalt Waste Isolation Project to simulate nonisothermal groundwater flow in a heterogeneous anisotropic medium and heat transport in a water/rock system near a high level nuclear waste repository. Allows three representations of the hydrogeologic system: an equivalent porous continuum, a system of discrete, unfilled, and interconnecting fractures separated by impervious rock mass, and a low permeability porous continuum with several discrete, unfilled fractures traversing the medium. The calculations assume local thermodynamic equilibrium between the rock and groundwater, nonisothermal Darcian flow in the continuum portions of the rock, and nonisothermal Poiseuille flow in discrete unfilled fractures. In addition, the code accounts for thermal loading within the elements, zero normal gradient and fixed boundary conditions for both temperature and hydraulic head, and simulation of the temperature and flow independently. The Q2DGEOM preprocessor was developed to generate, modify, plot and verify quadratic two dimensional finite element geometries. The BCGEN preprocessor generates the boundary conditions for head and temperature and ICGEN generates the initial conditions. The GRIDDER postprocessor interpolates nonregularly spaced nodal flow and temperature data onto a regular rectangular grid. CONTOUR plots and labels contour lines for a function of two variables and PARAM plots cross sections and time histories for a function of time and one or two spatial variables. NPRINT generates data tables that display the data along horizontal or vertical cross sections. VELPLT differentiates the hydraulic head and buoyancy data and plots the velocity vectors. The PATH postprocessor plots flow paths and computes the corresponding travel times.

  13. MAGNUM2D. Radionuclide Transport Porous Media

    SciTech Connect

    Langford, D.W.; Baca, R.G.

    1988-08-01

    MAGNUM2D was developed to analyze thermally driven fluid motion in the deep basalts below the Paco Basin at the Westinghouse Hanford Site. Has been used in the Basalt Waste Isolation Project to simulate nonisothermal groundwater flow in a heterogeneous anisotropic medium and heat transport in a water/rock system near a high level nuclear waste repository. Allows three representations of the hydrogeologic system: an equivalent porous continuum, a system of discrete, unfilled, and interconnecting fractures separated by impervious rock mass, and a low permeability porous continuum with several discrete, unfilled fractures traversing the medium. The calculation assumes local thermodynamic equilibrium between the rock and groundwater, nonisothermal Darcian flow in the continuum portions of the rock, and nonisothermal Poiseuille flow in discrete unfilled fractures. In addition, the code accounts for thermal loading within the elements, zero normal gradient and fixed boundary conditions for both temperature and hydraulic head, and simulation of the temperature and flow independently. The Q2DGEOM preprocessor was developed to generate, modify, plot and verify quadratic two dimensional finite element geometries. The BCGEN preprocessor generates the boundary conditions for head and temperature and ICGEN generates the initial conditions. The GRIDDER postprocessor interpolates nonregularly spaced nodal flow and temperature data onto a regular rectangular grid. CONTOUR plots and labels contour lines for a function of two variables and PARAM plots cross sections and time histories for a function of time and one or two spatial variables. NPRINT generates data tables that display the data along horizontal or vertical cross sections. VELPLT differentiates the hydraulic head and buoyancy data and plots the velocity vectors. The PATH postprocessor plots flow paths and computes the corresponding travel times.

  14. Apparatus for the measurement of radionuclide transport rates in rock cores

    SciTech Connect

    Weed, H.C.; Koszykowski, R.F.; Dibley, L.L.; Murray, I.

    1981-09-01

    An apparatus and procedure for the study of radionuclide transport in intact rock cores are presented in this report. This equipment more closely simulates natural conditions of radionuclide transport than do crushed rock columns. The apparatus and the procedure from rock core preparation through data analysis are described. The retardation factors measured are the ratio of the transport rate of a non-retarded radionuclide, such as /sup 3/H, to the transport rate of a retarded radionuclide. Sample results from a study of the transport of /sup 95m/Tc and /sup 85/Sr in brine through a sandstone core are included.

  15. Chapter II.C Transport of Radionuclides through Soil and Ground Water

    SciTech Connect

    Corey, J.C.

    1980-12-23

    The purpose of this report is to provide a clearer perspective of the impact of radionuclides in soil and groundwater, particularly for those not well-versed in soil science, hydrology, and geology. Through nuclear waste disposal or accidents, radionuclides come in contact with soil and groundwater. Man is exposed to radiation as a result of movement (or transport) of the radionuclides into his environment. Water is the principal carrier that induces transport, but chemical characteristics of soil inhibit the transport.

  16. Chancellor Water Colloids: Characterization and Radionuclide Associated Transport

    SciTech Connect

    Reimus, Paul William; Boukhalfa, Hakim

    2014-09-26

    Column transport experiments were conducted in which water from the Chancellor nuclear test cavity was transported through crushed volcanic tuff from Pahute Mesa. In one experiment, the cavity water was spiked with solute 137Cs, and in another it was spiked with 239/240Pu(IV) nanocolloids. A third column experiment was conducted with no radionuclide spike at all, although the 137Cs concentrations in the water were still high enough to quantify in the column effluent. The radionuclides strongly partitioned to natural colloids present in the water, which were characterized for size distribution, mass concentration, zeta potential/surface charge, critical coagulation concentration, and qualitative mineralogy. In the spiked water experiments, the unanalyzed portion of the high-concentration column effluent samples were combined and re-injected into the respective columns as a second pulse. This procedure was repeated again for a third injection. Measurable filtration of the colloids was observed after each initial injection of the Chancellor water into the columns, but the subsequent injections (spiked water experiments only) exhibited no apparent filtration, suggesting that the colloids that remained mobile after relatively short transport distances were more resistant to filtration than the initial population of colloids. It was also observed that while significant desorption of 137Cs from the colloids occurred after the first injection in both the spiked and unspiked waters, subsequent injections of the spiked water exhibited much less 137Cs desorption (much greater 137Cs colloid-associated transport). This result suggests that the 137Cs that remained associated with colloids during the first injection represented a fraction that was more strongly adsorbed to the mobile colloids than the initial 137Cs associated with the colloids. A greater amount of the 239/240

  17. PATHWAY: a simulation model of radionuclide-transport through agricultural food chains

    SciTech Connect

    Kirchner, T.B.; Whicker, F.W.; Otis, M.D.

    1982-01-01

    PATHWAY simulates the transport of radionuclides from fallout through an agricultural ecosystem. The agro-ecosystem is subdivided into several land management units, each of which is used either for grazing animals, for growing hay, or for growing food crops. The model simulates the transport of radionuclides by both discrete events and continuous, time-dependent processes. The discrete events include tillage of soil, harvest and storage of crops,and deposition of fallout. The continuous processes include the transport of radionuclides due to resuspension, weathering, rain splash, percolation, leaching, adsorption and desorption of radionuclides in the soil, root uptake, foliar absorption, growth and senescence of vegetation, and the ingestion assimilation, and excretion of radionuclides by animals. Preliminary validation studies indicate that the model dynamics and simulated values of radionuclide concentrations in several agricultural products agree well with measured values when the model is driven with site specific data on deposition from world-wide fallout.

  18. COLLOID-FACILITATED TRANSPORT OF RADIONUCLIDES THROUGH THE VADOSE ZONE

    SciTech Connect

    Flury, Markus

    2003-09-14

    close relations to the following EMSP projects: Project: 70126, Interfacial Soil Chemistry of Radionuclides in the Unsaturated Zone (PI: Jon Chorover) Project: 70070, Reactivity of Primary Soil Minerals and Secondary Precipitates (PI: Kathy Nagy) Cesium Transport in Hanford Sediments: Application of an Experimentally Based Cation Exchange Model (PI: Susan Carroll and Carl Steefel).

  19. Mobility of Source Zone Heavy Metals and Radionuclides: The Mixed Roles of Fermentative Activity on Fate and Transport of U and Cr

    SciTech Connect

    Apel, William; Peyton, Brent; Gerlach, Robin; Lee, Brady

    2006-06-01

    Predicting the potential migration of metals and radionuclides from waste pits and trenches will require understanding the effects of carbon and electron flow through these environments. Important aspects of this flow include the physiological activity of cellulolytic and non-cellulolytic fermentative microbial populations, as well as the subsequent activity of metal and radionuclide reducing bacteria. The activity of subsurface fermentative microbial populations is significantly understudied even though these organisms can affect contaminant migration by at least two mechanisms. In the first mechanism, products of the fermentation process can act as chelators for metals and radionuclides increasing their transport through underlying geological media. The second mechanism is the reduction and immobilization of metals and radionuclides since some fermentative bacteria have been shown to directly reduce metals and radionuclides, while their fermentation products can provide carbon and energy for respiratory metal reducing bacteria that can also reduce oxidized metals and radionuclides.

  20. Radionuclide Gas Transport through Nuclear Explosion-Generated Fracture Networks

    NASA Astrophysics Data System (ADS)

    Jordan, Amy B.; Stauffer, Philip H.; Knight, Earl E.; Rougier, Esteban; Anderson, Dale N.

    2015-12-01

    Underground nuclear weapon testing produces radionuclide gases which may seep to the surface. Barometric pumping of gas through explosion-fractured rock is investigated using a new sequentially-coupled hydrodynamic rock damage/gas transport model. Fracture networks are produced for two rock types (granite and tuff) and three depths of burial. The fracture networks are integrated into a flow and transport numerical model driven by surface pressure signals of differing amplitude and variability. There are major differences between predictions using a realistic fracture network and prior results that used a simplified geometry. Matrix porosity and maximum fracture aperture have the greatest impact on gas breakthrough time and window of opportunity for detection, with different effects between granite and tuff simulations highlighting the importance of accurately simulating the fracture network. In particular, maximum fracture aperture has an opposite effect on tuff and granite, due to different damage patterns and their effect on the barometric pumping process. From stochastic simulations using randomly generated hydrogeologic parameters, normalized detection curves are presented to show differences in optimal sampling time for granite and tuff simulations. Seasonal and location-based effects on breakthrough, which occur due to differences in barometric forcing, are stronger where the barometric signal is highly variable.

  1. Radionuclide gas transport through nuclear explosion-generated fracture networks

    SciTech Connect

    Jordan, Amy B.; Stauffer, Philip H.; Knight, Earl E.; Rougier, Esteban; Anderson, Dale N.

    2015-12-17

    Underground nuclear weapon testing produces radionuclide gases which may seep to the surface. Barometric pumping of gas through explosion-fractured rock is investigated using a new sequentially-coupled hydrodynamic rock damage/gas transport model. Fracture networks are produced for two rock types (granite and tuff) and three depths of burial. The fracture networks are integrated into a flow and transport numerical model driven by surface pressure signals of differing amplitude and variability. There are major differences between predictions using a realistic fracture network and prior results that used a simplified geometry. Matrix porosity and maximum fracture aperture have the greatest impact on gas breakthrough time and window of opportunity for detection, with different effects between granite and tuff simulations highlighting the importance of accurately simulating the fracture network. In particular, maximum fracture aperture has an opposite effect on tuff and granite, due to different damage patterns and their effect on the barometric pumping process. From stochastic simulations using randomly generated hydrogeologic parameters, normalized detection curves are presented to show differences in optimal sampling time for granite and tuff simulations. In conclusion, seasonal and location-based effects on breakthrough, which occur due to differences in barometric forcing, are stronger where the barometric signal is highly variable.

  2. Radionuclide gas transport through nuclear explosion-generated fracture networks

    DOE PAGES

    Jordan, Amy B.; Stauffer, Philip H.; Knight, Earl E.; ...

    2015-12-17

    Underground nuclear weapon testing produces radionuclide gases which may seep to the surface. Barometric pumping of gas through explosion-fractured rock is investigated using a new sequentially-coupled hydrodynamic rock damage/gas transport model. Fracture networks are produced for two rock types (granite and tuff) and three depths of burial. The fracture networks are integrated into a flow and transport numerical model driven by surface pressure signals of differing amplitude and variability. There are major differences between predictions using a realistic fracture network and prior results that used a simplified geometry. Matrix porosity and maximum fracture aperture have the greatest impact on gasmore » breakthrough time and window of opportunity for detection, with different effects between granite and tuff simulations highlighting the importance of accurately simulating the fracture network. In particular, maximum fracture aperture has an opposite effect on tuff and granite, due to different damage patterns and their effect on the barometric pumping process. From stochastic simulations using randomly generated hydrogeologic parameters, normalized detection curves are presented to show differences in optimal sampling time for granite and tuff simulations. In conclusion, seasonal and location-based effects on breakthrough, which occur due to differences in barometric forcing, are stronger where the barometric signal is highly variable.« less

  3. Radionuclide Gas Transport through Nuclear Explosion-Generated Fracture Networks

    PubMed Central

    Jordan, Amy B.; Stauffer, Philip H.; Knight, Earl E.; Rougier, Esteban; Anderson, Dale N.

    2015-01-01

    Underground nuclear weapon testing produces radionuclide gases which may seep to the surface. Barometric pumping of gas through explosion-fractured rock is investigated using a new sequentially-coupled hydrodynamic rock damage/gas transport model. Fracture networks are produced for two rock types (granite and tuff) and three depths of burial. The fracture networks are integrated into a flow and transport numerical model driven by surface pressure signals of differing amplitude and variability. There are major differences between predictions using a realistic fracture network and prior results that used a simplified geometry. Matrix porosity and maximum fracture aperture have the greatest impact on gas breakthrough time and window of opportunity for detection, with different effects between granite and tuff simulations highlighting the importance of accurately simulating the fracture network. In particular, maximum fracture aperture has an opposite effect on tuff and granite, due to different damage patterns and their effect on the barometric pumping process. From stochastic simulations using randomly generated hydrogeologic parameters, normalized detection curves are presented to show differences in optimal sampling time for granite and tuff simulations. Seasonal and location-based effects on breakthrough, which occur due to differences in barometric forcing, are stronger where the barometric signal is highly variable. PMID:26676058

  4. Identification and characterization of potential discharge areas for radionuclide transport by groundwater from a nuclear waste repository in Sweden.

    PubMed

    Berglund, Sten; Bosson, Emma; Selroos, Jan-Olof; Sassner, Mona

    2013-05-01

    This paper describes solute transport modeling carried out as a part of an assessment of the long-term radiological safety of a planned deep rock repository for spent nuclear fuel in Forsmark, Sweden. Specifically, it presents transport modeling performed to locate and describe discharge areas for groundwater potentially carrying radionuclides from the repository to the surface where man and the environment could be affected by the contamination. The modeling results show that topography to large extent determines the discharge locations. Present and future lake and wetland objects are central for the radionuclide transport and dose calculations in the safety assessment. Results of detailed transport modeling focusing on the regolith and the upper part of the rock indicate that the identification of discharge areas and objects considered in the safety assessment is robust in the sense that it does not change when a more detailed model representation is used.

  5. Three-Dimensional Radionuclide Transport Through the Unsaturated Zone of the Yucca Mountain Site 3 Colloids

    SciTech Connect

    G. J. Moridis; Y. Seol

    2007-01-26

    The authors investigated colloid transport in the unsaturated fractured zone by means of three-dimensional site-scale numerical model under present-day climate infiltration, considering varying colloid diameters, kinetic declogging, and filtration. The radionuclide transport model was used to simulate continuous release of colloids into fractures throughout the proposed repository, in which any components of engineered barrier system such as waste package or drip shield were not considered. the results of the study indicate the importance of subsurface geology and site hydrology, i.e., the presence of faults (they dominate and control transport), fractures (the main migration pathways), and the relative distribution of zeolitic and vitric tuffs. The simulations indicate that (1) colloid transport is not significantly affected by varying the filtration parameters, (2) travel time to the water table decreases with the colloid size, (3) larger colloids show little retardation whereas very small ones are retarded significantly, and (4) fracture filtration can have an impact on transport. Because of uncertainties in the fundamentals of colloid transport and an extremely conservative approach (based on an improbably adverse worst-case scenario), caution should be exercised in the analysis and interpretation of the 3-D simulation results. The results discussed here should be viewed as an attempt to identify and evaluate the mechanisms, processes, and geological features that control colloidal transport.

  6. Colloid-Facilitated Transport of Radionuclides Through the Vadose Zone

    SciTech Connect

    Flury, Markus; Lichtner, Peter C.; McCarthy, John F.

    2003-06-01

    We have completed the studies on reactions of minerals with caustic Hanford tank waste solutions. Systematic studies on the effects of different anions, cations, and the radionuclide Cs-137 were completed and technical manuscripts on these experiments were submitted for publication. The concentration of NaOH and the type of anion played the dominant roles in determining minerals formed. Increasing NaOH concentration and temperature enhanced the formation of feldspathoids; when NaOH concentration was high (e.g.,16 M), stable cancrinite and sodalite formed rapidly. Cancrinite formed in the presence of nitrate or sulfate; sodalite formed in the presence of chloride, carbonate or without added anions. Low concentration of Cs (< 100 mM) did not affect the formation of lepispheric cancrinite and sodalite, whereas only highly crystalline cancrinite formed when Cs concentration was >250mM. The presence of K did not alter but slowed down the formation of cancrinite and sodalite. The presence of divalent cations led to the formation of intermediate or stable silicates, aluminates, hydroxides or even aluminosilicates. We investigated the incorporation of Cs and the stability of the incorporated Cs in feldspathoids, zeolites, and allophane that may form in the sediments under conditions mimicking Hanford tank leaks. The incorporated Cs was quantified by atomic absorption spectroscopy after digestion in 1 M HCl. Cancrinite, sodalite, LTA zeolite, the 3-D cross-shaped zeolite, and allophane were capable to preferentially incorporate Cs when they form in the alkaline simulants.

  7. Subsurface Characterization To Support Evaluation Of Radionuclide Transport And Attenuation

    EPA Science Inventory

    Remediation of ground water contaminated with radionuclides may be achieved using attenuation-based technologies. These technologies may rely on engineered processes (e.g., bioremediation) or natural processes (e.g., monitored natural attenuation) within the subsurface. In gene...

  8. Factors affecting radionuclide availability to vegetables grown at Los Alamos

    SciTech Connect

    White, G.C.; Hakonson, T.E.; Ahlquist, A.J.

    1981-07-01

    A field study was conducted in 1977 on /sup 238/ /sup 239/Pu and /sup 137/Cs availability to zucchini squash (Curcurbita melopepo, hybrid seneca) and green bush beans (Phaseolus vulgaris, Landreths stringless) grown under home-garden conditions in an area at Los Alamos National Laboratory used for treated radioactive liquid waste disposal. Radionuclide concentrations were measured as a function of tissue type, height above the soil, fertilization regime, and for the squash, food-cleansing procedures. Analysis of variance procedures was used to analyze the data. Ratios of the concentration of a radionuclide in oven-dried vegetation to dry soil ranged from 0.0004 to 0.116 for the Pu isotopes, and from 0.051 to 0.255 for /sup 137/Cs. Fertilization with cattle manure reduced the Pu concentration ratios by 30% and /sup 137/Cs by 50%. Vegetative parts sampled within 20 cm of the ground surface were contaminated about four times as much as those parts growing further from the ground surface. About 65% of the contamination was removed by washing, indicating the presence of surficial contamination. The 50-year radiation dose commitment to humans consuming vegetables from the garden plot would be less than 0.05 mrem and would be due almost entirely to /sup 137/Cs.

  9. Pacific bluefin tuna transport Fukushima-derived radionuclides from Japan to California

    PubMed Central

    Madigan, Daniel J.; Baumann, Zofia; Fisher, Nicholas S.

    2012-01-01

    The Fukushima Dai-ichi release of radionuclides into ocean waters caused significant local and global concern regarding the spread of radioactive material. We report unequivocal evidence that Pacific bluefin tuna, Thunnus orientalis, transported Fukushima-derived radionuclides across the entire North Pacific Ocean. We measured γ-emitting radionuclides in California-caught tunas and found 134Cs (4.0 ± 1.4 Bq kg−1) and elevated 137Cs (6.3 ± 1.5 Bq kg−1) in 15 Pacific bluefin tuna sampled in August 2011. We found no 134Cs and background concentrations (∼1 Bq kg−1) of 137Cs in pre-Fukushima bluefin and post-Fukushima yellowfin tunas, ruling out elevated radiocesium uptake before 2011 or in California waters post-Fukushima. These findings indicate that Pacific bluefin tuna can rapidly transport radionuclides from a point source in Japan to distant ecoregions and demonstrate the importance of migratory animals as transport vectors of radionuclides. Other large, highly migratory marine animals make extensive use of waters around Japan, and these animals may also be transport vectors of Fukushima-derived radionuclides to distant regions of the North and South Pacific Oceans. These results reveal tools to trace migration origin (using the presence of 134Cs) and potentially migration timing (using 134Cs:137Cs ratios) in highly migratory marine species in the Pacific Ocean. PMID:22645346

  10. Colloid-Facilitated Transport of Low-Solubility Radionuclides: A Field, Experimental, and Modeling Investigation

    SciTech Connect

    Kersting, A B; Reimus, P W; Abdel-Fattah, A; Allen, P G; Anghel, I; Benedict, F C; Esser, B K; Lu, N; Kung, K S; Nelson, J; Neu, M P; Reilly, S D; Smith, D K; Sylwester, E R; Wang, L; Ware, S D; Warren, RG; Williams, R W; Zavarin, M; Zhao, P

    2003-02-01

    For the last several years, the Underground Test Area (UGTA) program has funded a series of studies carried out by scientists to investigate the role of colloids in facilitating the transport of low-solubility radionuclides in groundwater, specifically plutonium (Pu). Although the studies were carried out independently, the overarching goals of these studies has been to determine if colloids in groundwater at the NTS can and will transport low-solubility radionuclides such as Pu, define the geochemical mechanisms under which this may or may not occur, determine the hydrologic parameters that may or may not enhance transport through fractures and provide recommendations for incorporating this information into future modeling efforts. The initial motivation for this work came from the observation in 1997 and 1998 by scientists from Lawrence Livermore National Laboratory (LLNL) and Los Alamos National Laboratory (LANL) that low levels of Pu originally from the Benham underground nuclear test were detected in groundwater from two different aquifers collected from wells 1.3 km downgradient (Kersting et al., 1999). Greater than 90% of the Pu and other radionuclides were associated with the naturally occurring colloidal fraction (< 1 micron particles) in the groundwater. The colloids consisted mainly of zeolite (mordenite, clinoptilolite/heulandite), clays (illite, smectite) and cristobalite (SiO{sub 2}). These minerals were also identified as alteration mineral components in the host rock aquifer, a rhyolitic tuff. The observation that Pu can and has migrated in the subsurface at the NTS has forced a rethinking of our basic assumptions regarding the mechanical and geochemical transport pathways of low-solubility radionuclides. If colloid-facilitated transport is the primary mechanism for transporting low-solubility radionuclides in the subsurface, then current transport models based solely on solubility arguments and retardation estimates may underestimate the flux and

  11. RIVER-RAD: A computer code for simulating the transport of radionuclides in rivers

    SciTech Connect

    Hetrick, D.M.; McDowell-Boyer, L.M.; Sjoreen, A.L.; Thorne, D.J.; Patterson, M.R.

    1992-11-01

    A screening-level model, RIVER-RAD, has been developed to assess the potential fate of radionuclides released to rivers. The model is simplified in nature and is intended to provide guidance in determining the potential importance of the surface water pathway, relevant transport mechanisms, and key radionuclides in estimating radiological dose to man. The purpose of this report is to provide a description of the model and a user's manual for the FORTRAN computer code.

  12. Analytical model for radionuclide transport in the buffer zone of the deep geological disposal

    NASA Astrophysics Data System (ADS)

    Tsao, L. D.; Chen, J. S.; Li, M. H.

    2015-12-01

    Radioactive nuclear waste poses long-term threat to human beings and the environment because that remains radioactive after millions of years. Therefore, radioactive wastes must be isolated from the living environment for millennia. A deep geological disposal entails a combination of four parts: vitrified waste form, imaginary zone, buffer zone and excavation-affected zone. The buffer zone constituted by bentonite clay provides a high level of containment of the radioactivity in the wastes over a very long time period. Analytical solution is an efficient tool for the performance evaluation of the buffer zone. This study develops a new analytical model to diffusion equation in cylindrical coordinate for describing radionuclide transport in the buffer zone. The derived solution is compared against the previous solution to illustrate the validity of previous solution which was derived using a diffusion equation in Cartesian coordinates.

  13. Preferential Radionuclide Transport in a Tuff with Altered Zones: Micro-scale Mapping

    NASA Astrophysics Data System (ADS)

    Hu, Q.; Liu, X.; Zuo, R.

    2009-12-01

    Understanding radionuclide transport in fractured rock is important for performance assessment of proposed radioactive waste disposal sites. We performed laboratory tests to study water imbibition and radionuclide transport into initially dry tuff by contacting one end of a sample with water containing a mixture of tracers (Re, 99Tc, Sr, Cs, 235U, 237Np, and 242Pu). The tuff sample, collected from Yucca Mountain, Nevada, is a cube 1-cm on each side and has a 1-mm thick altered gray zone embedded within the tuff matrix. Such gray zones are observed to be adjacent to lithophysae and fractures, are primarily quartz and tridymite, and have different hydraulic and chemical properties from the rock matrix. Capillary-driven imbibition transports tracer chemicals away from the imbibing face, causing separation of non-sorbing and sorbing tracers in tuff. Using a micro-scale profiling technique of laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), we directly mapped the distribution of radionuclides along the altered zone (as well as transverse to the unaltered matrix). We found that the altered zone shows higher permeability, and less retardation of sorbing radionuclides, than the unaltered matrix, leading to preferential transport along the altered zone. Transverse profiling of the unaltered matrix indicated only limited penetration of strongly sorbing radionuclides, such as Pu.

  14. Conceptual model for regional radionuclide transport from a basalt repository site. Final draft, technical memorandum

    SciTech Connect

    Walton, W.C.; Voorhees, M.L.; Prickett, T.A.

    1980-05-23

    This technical memorandum was prepared to: (1) describe a typical basalt radionuclide repository site, (2) describe geologic and hydrologic processes associated with regional radionuclide transport in basalts, (3) define the parameters required to model regional radionuclide transport from a basalt repository site, and (4) develop a ''conceptual model'' of radionuclide transport from a basalt repository site. In a general hydrological sense, basalts may be described as layered sequences of aquifers and aquitards. The Columbia River Basalt, centered near the semi-arid Pasco Basin, is considered by many to be typical basalt repository host rock. Detailed description of the flow system including flow velocities with high-low hydraulic conductivity sequences are not possible with existing data. However, according to theory, waste-transport routes are ultimately towards the Columbia River and the lengths of flow paths from the repository to the biosphere may be relatively short. There are many physical, chemical, thermal, and nuclear processes with associated parameters that together determine the possible pattern of radionuclide migration in basalts and surrounding formations. Brief process descriptions and associated parameter lists are provided. Emphasis has been placed on the use of the distribution coefficient in simulating ion exchange. The use of the distribution coefficient approach is limited because it takes into account only relatively fast mass transfer processes. In general, knowledge of hydrogeochemical processes is primitive.

  15. Conceptual model for regional radionuclide transport from a salt dome repository: a technical memorandum

    SciTech Connect

    Kier, R.S.; Showalter, P.A.; Dettinger, M.D.

    1980-05-30

    Disposal of high-level radioactive wastes is a major environmental problem influencing further development of nuclear energy in this country. Salt domes in the Gulf Coast Basin are being investigated as repository sites. A major concern is geologic and hydrologic stability of candidate domes and potential transport of radionuclides by groundwater to the biosphere prior to their degradation to harmless levels of activity. This report conceptualizes a regional geohydrologic model for transport of radionuclides from a salt dome repository. The model considers transport pathways and the physical and chemical changes that would occur through time prior to the radionuclides reaching the biosphere. Necessary, but unknown inputs to the regional model involve entry and movement of fluids through the repository dome and across the dome-country rock interface and the effect on the dome and surrounding strata of heat generated by the radioactive wastes.

  16. Inverse Modeling of Experiments to Support More Realistic Simulations of Sorbing Radionuclide Transport

    NASA Astrophysics Data System (ADS)

    Arnold, B. W.; James, S. C.; Reimus, P. W.

    2012-12-01

    A series of adsorption, desorption, and column transport experiments were conducted to evaluate the transport of uranium (U) and neptunium (Np) through saturated volcanic tuffs. For potential high-level radioactive waste sites, these experiments demonstrate that slow radionuclide desorption processes, which are typically not accounted for in transport models implementing simple partition coefficients (Kd values), may dominate field-scale transport. A complimentary interpretive numerical model couples a simplified geochemical description of the system with transport calculations where heterogeneities are represented as an ensemble of sorption sites with characteristic adsorption and desorption rate constants that have widely varying values. Adsorption and desorption rate constants were estimated through inverse modeling such that reliable upscaled predictions of reactive transport in field settings could be simulated. The inverse modeling software, PEST, was also used to perform advanced uncertainty quantification. The multicomponent model/parameters matching the combined data sets suggest that over much longer time and distance scales the transport of U and Np under the experimental conditions would result in very little transport over field scales because even a small number of strong sorption sites will have an exaggerated retarding influence on the transport of a radionuclide plume. Modeling of combined sorption/desorption experiments and column transport experiments that involve both the measurement of column effluent breakthrough curves and the distribution of radionuclides remaining in the column at the conclusion of the experiments holds significant promise for supporting an improved approach to properly account for mineralogical heterogeneity over long time and distance scales in reactive radionuclide transport models. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed

  17. Sorption-capacity limited retardation of radionuclides transport in water-saturated packing materials

    SciTech Connect

    Pescatore, C.; Sullivan, T.

    1984-01-01

    Radionuclides breakthrough times as calculated through constant retardation factors obtained in dilute solutions are non-conservative. The constant retardation approach regards the solid as having infinite sorption capacity throughout the solid. However, as the solid becomes locally saturated, such as in the proximity of the waste form-packing materials interface, it will exhibit no retardation properties, and transport will take place as if the radionuclides were locally non-reactive. The magnitude of the effect of finite sorption capacity of the packing materials on radionuclide transport is discussed with reference to high-level waste package performance. An example based on literature sorption data indicates that the breakthrough time may be overpredicted by orders of magnitude using a constant retardation factor as compared to using the entire sorption isotherm to obtain a concentration-dependent retardation factor. 8 references, 3 figures, 3 tables.

  18. Sediment and Radionuclide Transport in Rivers; Field Sampling Program, Cattaraugus and Buttermilk Creeks, New York

    SciTech Connect

    Onishi., Y.; Walters, W. H.; Ecker, R. M.

    1981-01-01

    This report describes FY-1979 analysis results on flow, sediment and radionuclide data collected in Cattaraugus, Buttermilk and Franks Creek, New York. The objective of the study is to investigate the radionuclide transport in these streams as a part of a continuing program to provide data required for application and verification of the Sediment and Radionuclide Transport Model (SERATRA). Radiological analyses were performed on sand, silt and clay size fractions of suspended and bed sediment, as well as for dissolved radionuclides. These include gamma-ray emitters plus {sup 90}Sr, {sup 238}Pu, {sup 239 - 240}Pu, {sup 241}Am, {sup 244}Cm and {sup 3}H. Among radionuclides analyzed to date, a principal radionuclide found in the study area is {sup 137}Cs. Distributions of {sup 137}Cs associated with suspended and bed sediments have sharp peaks at the mouth of the Franks Creek, revealing the contribution of {sup 137}Cs from the NFS site. Concentration of {sup 137}Cs associated with a clay size fraction of suspended and bed sediments at the mouth of Franks Creek were 32.5 {+-} 1.5 and 134.0 {+-} 0.90 pCi/g, respectively. Cesium-134 and cobalt-60 associated with the bed sediment also have higher peaks at the mouth of Franks Creek. However, dissolved and particulate concentrations of other radionuclides analyzed under this study were generally very low and there is no clear evidence to indicate that these radionculides detected in this study area originated from the Nuclear Fuel Service site.

  19. Transport of fallout and reactor radionuclides in the drainage basin of the Hudson River estuary

    SciTech Connect

    Simpson, H.J.; Linsalata, P.; Olsen, C.R.

    1982-01-01

    The transport and fate of Strontium 90, Cesium 137 and Plutonium 239, 240 in the Hudson River Estuary is discussed. Rates of radionuclide deposition and accumulation over time and space are calculated for the Hudson River watershed, estuary, and continental shelf offshore. 37 references, 7 figures, 15 tables. (ACR)

  20. The Role of Dispersion in Radionuclide Transport - Data and Modeling Requirements: Revision No. 1

    SciTech Connect

    Stoller-Navarro Joint Venture

    2004-02-01

    This document is the collaborative effort of the members of an ad hoc subcommittee of the Underground Test Area Project Technical Working Group. This subcommittee was to answer questions and concerns raised by the Nevada Division of Environmental Protection to the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office, regarding Pahute Mesa Corrective Action Units (CAUs) 101 and 102. The document attempts to synthesize the combined comments made by each member of this subcommittee into insights made in the role of dispersion in radionuclide transport data and modeling. Dispersion is one of many processes that control the concentration of radionuclides in groundwater beneath the Nevada Test Site where CAUs 101 and 102 are located. In order to understand the role of dispersion in radionuclide transport, there is a critical need for CAU- or site-specific data related to transport parameters which is currently lacking, particularly in the case of Western a nd Central Pahute Mesa. The purpose of this technical basis document is to: (1) define dispersion and its role in contaminant transport, (2) present a synopsis of field-scale dispersion measurements, (3) provide a literature review of theories to explain field-scale dispersion, (4) suggest approaches to account for dispersion in CAU-scale radionuclide modeling, and (5) to determine if additional dispersion measurements should be made at this time.

  1. Towards a unified modeling system of predicting the transport of radionuclides in coastal sea regions

    NASA Astrophysics Data System (ADS)

    Jung, Kyung Tae; Brovchenko, Igor; Maderich, Vladimir; Kim, Kyeong Ok; Qiao, Fangli

    2016-04-01

    We present in this talk a recent progress in developing a unified modeling system of predicting three-dimensional transport of radionuclides coupled with multiple-scale circulation, wave and suspended sediment modules, keeping in mind the application to coastal sea regions with non-uniform distribution of suspended and bed sediments of both cohesive and non-cohesive types. The model calculates the concentration fields of dissolved and particulate radionuclides in bottom sediment as well as in water column. The transfer of radioactivity between the water column and the pore water in the upper layer of the bottom sediment is governed by diffusion processes. The phase change between dissolved and particulate radionuclides is written in terms of absorption/desorption rates and distribution coefficients. The dependence of distribution coefficients is inversely proportional to the sediment particle size. The hydrodynamic numerical model SELFE that solves equations for the multiple-scale circulation, the wave action and sand transport on the unstructured grids has been used as a base model. We have extended the non-cohesive sediment module of SELFE to the form applicable to mixture of cohesive and non-cohesive sedimentary regimes by implementing an extended form of erosional rate and a flocculation model for the determination of settling velocity of cohesive flocs. Issues related to the calibration of the sediment transport model in the Yellow Sea are described. The radionuclide transport model with one-step transfer kinetics and single bed layer has been initially developed and then applied to Fukushima Daiichi nuclear accident. The model has been in this study verified through the comparison with measurements of 137Cs concentration in bed sediments. Preliminary application to the Yellow and East China Seas with a hypothetical release scenario are described. On-going development of the radionuclide transport model using two-step transfer kinetics and multiple bed layers

  2. Edaphic factors affecting the vertical distribution of radionuclides in the different soil types of Belgrade, Serbia.

    PubMed

    Dragović, Snežana; Gajić, Boško; Dragović, Ranko; Janković-Mandić, Ljiljana; Slavković-Beškoski, Latinka; Mihailović, Nevena; Momčilović, Milan; Ćujić, Mirjana

    2012-01-01

    The specific activities of natural radionuclides ((40)K, (226)Ra and (232)Th) and Chernobyl-derived (137)Cs were measured in soil profiles representing typical soil types of Belgrade (Serbia): chernozems, fluvisols, humic gleysols, eutric cambisols, vertisols and gleyic fluvisols. The influence of soil properties and content of stable elements on radionuclide distribution down the soil profiles (at 5 cm intervals up to 50 cm depth) was analysed. Correlation analysis identified associations of (40)K, (226)Ra and (137)Cs with fine-grained soil fractions. Significant positive correlations were found between (137)Cs specific activity and both organic matter content and cation exchange capacity. Saturated hydraulic conductivity and specific electrical conductivity were also positively correlated with the specific activity of (137)Cs. The strong positive correlations between (226)Ra and (232)Th specific activities and Fe and Mn indicate an association with oxides of these elements in soil. The correlations observed between (40)K and Cr, Ni, Pb and Zn and also between (137)Cs and Cd, Cr, Pb and Zn could be attributed to their common affinity for clay minerals. These results provide insight into the main factors that affect radionuclide migration in the soil, which contributes to knowledge about radionuclide behaviour in the environment and factors governing their mobility within terrestrial ecosystems.

  3. Atmospheric Transport Modelling confining potential source location of East-Asian radionuclide detections in May 2010

    NASA Astrophysics Data System (ADS)

    Ross, J. Ole; Ceranna, Lars

    2016-04-01

    The radionuclide component of the International Monitoring System (IMS) to verify compliance with the Comprehensive Nuclear-Test-Ban Treaty (CTBT) is in place to detect tiny traces of fission products from nuclear explosions in the atmosphere. The challenge for the interpretation of IMS radionuclide data is to discriminate radionuclide sources of CTBT relevance against emissions from nuclear facilities. Remarkable activity concentrations of Ba/La-140 occurred at the IMS radionuclide stations RN 37 (Okinawa) and RN 58 (Ussurysk) mid of May 2010. In those days also an elevated Xe-133 level was measured at RN 38 (Takasaki). Additional regional measurements of radioxenon were reported in the press and further analyzed in various publications. The radionuclide analysis gives evidence for the presence of a nuclear fission source between 10 and 12 May 2010. Backward Atmospheric Transport Modelling (ATM) with HYSPLIT driven by 0.2° ECMWF meteorological data for the IMS samples indicates that, assuming a single source, a wide range of source regions is possible including the Korean Peninsula, the Sea of Japan (East Sea), and parts of China and Russia. Further confinement of the possible source location can be provided by atmospheric backtracking for the assumed sampling periods of the reported regional xenon measurements. New studies indicate a very weak seismic event at the DPRK test site on early 12 May 2010. Forward ATM for a pulse release caused by this event shows fairly good agreement with the observed radionuclide signature. Nevertheless, the underlying nuclear fission scenario remains quite unclear and speculative even if assuming a connection between the waveform and the radionuclide event.

  4. The role of organic complexants and microparticulates in the facilitated transport of radionuclides

    SciTech Connect

    Schilk, A.J.; Robertson, D.E.; Abel, K.H.; Thomas, C.W.

    1996-12-01

    This progress report describes the results of ongoing radiological and geochemical investigations of the mechanisms of radionuclide transport in groundwater at two low-level waste (LLW) disposal sites within the waste management area of the Chalk River Laboratories (CRL), Ontario, Canada. These sites, the Chemical Pit liquid disposal facility and the Waste Management Area C solid LLW disposal site, have provided valuable 30- to 40-year-old field locations for characterizing the migration of radionuclides and evaluating a number of recent site performance objectives for LLW disposal facilities. This information will aid the NRC and other federal, state, and local regulators, as well as LLW disposal site developers and waste generators, in maximizing the effectiveness of existing or projected LLW disposal facilities for isolating radionuclides from the general public and thereby improving the health and safety aspects of LLW disposal.

  5. Colloid-Facilitated Transport of Radionuclides through the Vadose Zone

    SciTech Connect

    Flury, Markus; Harsh, James B.; Zachara, John M.; McCarthy, John F.; Lichtner, Peter C.

    2006-05-31

    This project seeks to improve the basic understanding of the role of colloids in facilitating the transport of contaminants in the vadose zone. We focus on three major thrusts: (1) thermodynamic stability and mobility of colloids formed by reactions of sediments with highly alkaline tank waste solutions, (2) colloid-contaminant interactions, and (3) in-situ colloid mobilization and colloid facilitated contaminant transport occurring in both contaminated and uncontaminated Hanford sediments.

  6. Toward a Mechanistic Source Term in Advanced Reactors: Characterization of Radionuclide Transport and Retention in a Sodium Cooled Fast Reactor

    SciTech Connect

    Brunett, Acacia J.; Bucknor, Matthew; Grabaskas, David

    2016-04-17

    A vital component of the U.S. reactor licensing process is an integrated safety analysis in which a source term representing the release of radionuclides during normal operation and accident sequences is analyzed. Historically, source term analyses have utilized bounding, deterministic assumptions regarding radionuclide release. However, advancements in technical capabilities and the knowledge state have enabled the development of more realistic and best-estimate retention and release models such that a mechanistic source term assessment can be expected to be a required component of future licensing of advanced reactors. Recently, as part of a Regulatory Technology Development Plan effort for sodium cooled fast reactors (SFRs), Argonne National Laboratory has investigated the current state of knowledge of potential source terms in an SFR via an extensive review of previous domestic experiments, accidents, and operation. As part of this work, the significant sources and transport processes of radionuclides in an SFR have been identified and characterized. This effort examines all stages of release and source term evolution, beginning with release from the fuel pin and ending with retention in containment. Radionuclide sources considered in this effort include releases originating both in-vessel (e.g. in-core fuel, primary sodium, cover gas cleanup system, etc.) and ex-vessel (e.g. spent fuel storage, handling, and movement). Releases resulting from a primary sodium fire are also considered as a potential source. For each release group, dominant transport phenomena are identified and qualitatively discussed. The key product of this effort was the development of concise, inclusive diagrams that illustrate the release and retention mechanisms at a high level, where unique schematics have been developed for in-vessel, ex-vessel and sodium fire releases. This review effort has also found that despite the substantial range of phenomena affecting radionuclide release, the

  7. Atmospheric transport of radionuclides emitted due to wildfires near the Chernobyl Nuclear Power Plant in 2015

    NASA Astrophysics Data System (ADS)

    Evangeliou, Nikolaos; Zibtsev, Sergey; Myroniuk, Viktor; Zhurba, Marina; Hamburger, Thomas; Stohl, Andreas; Balkanski, Yves; Paugam, Ronan; Mousseau, Timothy A.; Møller, Anders P.; Kireev, Sergey I.

    2016-04-01

    In 2015, two major fires in the Chernobyl Exclusion Zone (CEZ) have caused concerns about the secondary radioactive contamination that might have spread over Europe. The total active burned area was estimated to be about 15,000 hectares, of which 9000 hectares burned in April and 6000 hectares in August. The present paper aims to assess, for the first time, the transport and impact of these fires over Europe. For this reason, direct observations of the prevailing deposition levels of 137Cs and 90Sr, 238Pu, 239Pu, 240Pu and 241Am in the CEZ were processed together with burned area estimates. Based on literature reports, we made the conservative assumption that 20% of the deposited labile radionuclides 137Cs and 90Sr, and 10% of the more refractory 238Pu, 239Pu, 240Pu and 241Am, were resuspended by the fires. We estimate that about 10.9 TBq of 137Cs, 1.5 TBq of 90Sr, 7.8 GBq of 238Pu, 6.3 GBq of 239Pu, 9.4 GBq of 240Pu and 29.7 GBq of 241Am were released from both fire events. These releases could be classified as of "Level 3" on the relative INES (International Nuclear Events Scale) scale, which corresponds to a serious incident, in which non-lethal deterministic effects are expected from radiation. To simulate the dispersion of the resuspended radionuclides in the atmosphere and their deposition onto the terrestrial environment, we used a Lagrangian dispersion model. Spring fires redistributed radionuclides over the northern and eastern parts of Europe, while the summer fires also affected Central and Southern Europe. The more labile elements escaped more easily from the CEZ and then reached and deposited in areas far from the source, whereas the larger refractory particles were removed more efficiently from the atmosphere and thus did mainly affect the CEZ and its vicinity. For the spring 2015 fires, we estimate that about 80% of 137Cs and 90Sr and about 69% of 238Pu, 239Pu, 240Pu and 241Am were deposited over areas outside the CEZ. 93% of the labile and 97% of

  8. Transport of Gas Phase Radionuclides in a Fractured, Low-Permeability Reservoir

    NASA Astrophysics Data System (ADS)

    Cooper, C. A.; Chapman, J.

    2001-12-01

    The U.S. Atomic Energy Commission (predecessor to the Department of Energy, DOE) oversaw a joint program between industry and government in the 1960s and 1970s to develop technology to enhance production from low-permeability gas reservoirs using nuclear stimulation rather than conventional means (e.g., hydraulic and/or acid fracturing). Project Rio Blanco, located in the Piceance Basin, Colorado, was the third experiment under the program. Three 30-kiloton nuclear explosives were placed in a 2134 m deep well at 1780, 1899, and 2039 m below the land surface and detonated in May 1973. Although the reservoir was extensively fractured, complications such as radionuclide contamination of the gas prevented production and subsequent development of the technology. Two-dimensional numerical simulations were conducted to identify the main transport processes that have occurred and are currently occurring in relation to the detonations, and to estimate the extent of contamination in the reservoir. Minor modifications were made to TOUGH2, the multiphase, multicomponent reservoir simulator developed at Lawrence Berkeley National Laboratories. The simulator allows the explicit incorporation of fractures, as well as heat transport, phase change, and first order radionuclide decay. For a fractured two-phase (liquid and gas) reservoir, the largest velocities are of gases through the fractures. In the gas phase, tritium and one isotope of krypton are the principle radionuclides of concern. However, in addition to existing as a fast pathway, fractures also permit matrix diffusion as a retardation mechanism. Another retardation mechanism is radionuclide decay. Simulations show that incorporation of fractures can significantly alter transport rates, and that radionuclides in the gas phase can preferentially migrate upward due to the downward gravity drainage of liquid water in the pores. This project was funded by the National Nuclear Security Administration, Nevada Operations Office

  9. Transport of gas-phase radionuclides in a fractured, low-permeability reservoir

    SciTech Connect

    Clay Cooper; Jenny Chapman

    2001-12-01

    The U.S. Atomic Energy Commission (predecessor to the U.S. Department of Energy, DOE) oversaw a joint program between industry and government in the 1960s and 1970s to develop technology to enhance production from low-permeability gas reservoirs using nuclear stimulation rather than conventional means (e.g., hydraulic and/or acid fracturing). Project Rio Blanco, located in the Piceance Basin, Colorado, was the third experiment under the program. Three 30-kiloton nuclear explosives were placed in a 2,134-m-deep well at 1,780, 1,899, and 2,039 m below the land surface and detonated in May 1973. Although the reservoir was extensively fractured, complications such as radionuclide contamination of the gas prevented production and subsequent development of the technology. Two-dimensional numerical simulations were conducted to identify the main transport processes that have occurred and are currently occurring in relation to the detonations, and to estimate the extent of contamination in the reservoir. Minor modifications were made to TOUGH2, the multiphase, multicomponent reservoir simulator developed at Lawrence Berkeley National Laboratories. The simulator allows the explicit incorporation of fractures, as well as heat transport, phase change, and first-order radionuclide decay. For a fractured, two-phase (liquid and gas) reservoir, the largest velocities are of gases through the fractures. In the gas phase, tritium and one isotope of krypton are the principal radionuclides of concern. However, in addition to existing as a fast pathway, fractures also permit matrix diffusion as a retardation mechanism. Another retardation mechanism is radionuclide decay. Simulations show that incorporation of fractures can significantly alter transport rates, and that radionuclides in the gas phase can preferentially migrate upward due to the downward gravity drainage of liquid water in the pores.

  10. Factors affecting the distribution of natural and anthropogenic radionuclides in the coastal Burullus Lake.

    PubMed

    El-Reefy, H I; Badran, H M; Sharshar, T; Hilal, M A; Elnimr, T

    2014-08-01

    In the present study, measurements of naturally occurring radioactive materials and (137)Cs activity in sediment were conducted for locations covering the entire Burullus Lake in order to gather information about radionuclides mobility and distribution. Low-background γ-spectrometry was employed to determine the activity concentrations of water and sediment samples. The activity concentrations of (226)Ra and (232)Th are close to uniform distribution in the lake environment. Among the different physical and chemical characteristics measured for water and sediment, only salinity and total organic matter content have the potential to affect the mobility of (137)Cs and (40)K. The results suggest that these two radionuclides are attached to different mobile particulates. Increasing salinity tends to strengthen the adsorption of (137)Cs and solubilization of (40)K in sediment. On the other hand, sediment with high organic matter content traps (137)Cs and (40)K associated particulates to bottom sediment.

  11. Transportation of radionuclides in urban environs: draft environmental assessment

    SciTech Connect

    Finley, N.C.; Aldrich, D.C.; Daniel, S.L.; Ericson, D.M.; Henning-Sachs, C.; Kaestner, P.C.; Ortiz, N.R.; Sheldon, D.D.; Taylor, J.M.

    1980-07-01

    This report assesses the environmental consequences of the transportation of radioactive materials in densely populated urban areas, including estimates of the radiological, nonradiological, and social impacts arising from this process. The chapters of the report and the appendices which follow detail the methodology and results for each of four causative event categories: incident free transport, vehicular accidents, human errors or deviations from accepted quality assurance practices, and sabotage or malevolent acts. The numerical results are expressed in terms of the expected radiological and economic impacts from each. Following these discussions, alternatives to the current transport practice are considered. Then, the detailed analysis is extended from a limited area of New York city to other urban areas. The appendices contain the data bases and specific models used to evaluate these impacts, as well as discussions of chemical toxicity and the social impacts of radioactive material transport in urban areas. The latter are evaluated for each causative event category in terms of psychological, sociological, political, legal, and organizational impacts. The report is followed by an extensive bibliography covering the many fields of study which were required in performing the analysis.

  12. Computer simulation of radionuclide transport through thermal convection of groundwater from borehole repositories

    SciTech Connect

    Malkovsky, V.I.; Pek, A.A.

    1993-09-01

    Results are presented of numerical modeling of radionuclide transport by thermal convection of groundwater from a single well repository of high level waste. Because the problem possesses cylindrical symmetry, the process is described by a system of 2-D transient equations for momentum, convective heat transfer and convective mass transfer (taking into account hydrodynamic dispersion and radionuclide decay). Results of computer simulations for a selected range of system parameters were generalized by approximating analytical relationship, which can be used for safety assessment of a radioactive waste repository. The problem of the reciprocal relationship between thermoconvective transport processes and well spacing in an underground repository with a regularly spaced set of the waste-loaded wells is examined using a two-well model as an example. In this case, the transport problem becomes three-dimensional. A solution to this problem was obtained using a special system of orthogonal coordinates, which simplifies the computational algorithm and enhances accuracy. It is shown that thermoconvective transport of radionuclides in the vicinity of each well can be considered to be independent at well separations of the order of 100 m when reasonable values of other repository parameters are assumed.

  13. Colloids and Radionuclide Transport: A Field, Experimental and Modeling Effort

    NASA Astrophysics Data System (ADS)

    Zhao, P.; Zavarin, M.; Sylwester, E. E.; Allen, P. G.; Williams, R. W.; Kersting, A. B.

    2002-05-01

    Natural inorganic colloids (< 1 micron particles) found in groundwater can sorb low-solubility actinides and may provide a pathway for transport through geological aquifers. The importance of colloid-facilitated transport to the transport of low-solubility actinides, such as Pu, is still not well understood. In an effort to better understand the dominant geochemical mechanisms that control Pu transport, we have performed a series of sorption/desorption experiments using mineral colloids. We focused on natural colloidal minerals present in water samples collected from both saturated and vadose zone waters at the Nevada Test Site. These minerals include zeolites, clays, silica, Mn-oxides, Fe-oxides, and calcite. X-ray absorption fine-structure spectroscopy ( both XANES and EXAFS) was performed in order to characterize the speciation of sorbed plutonium. The XANES spectra show that only Pu(IV) was detected (within experimental error) on these mineral surfaces when the starting Pu oxidation state was +5, indicating that Pu(V) was reduced to Pu(IV) during sorption. The EXAFS detected Pu-M and Pu-C interactions (where M=Fe, Mn, or Si) indicating Pu(IV) surface complexation along with carbonate ternary complex formation on most of the minerals tested. Although the plutonium sorption as Pu(IV) species is mineral independent, the actual sorption paths are different for different minerals. The sorption rates were compared to the rates of plutonium disproportionation under similar conditions. The batch sorption/desorption experiments of Pu(IV) and Pu(V) onto colloidal zeolite (clinoptilolite, colloids particle size 171 ñ 25 nm) were conducted in synthetic groundwater (similar to J-13, Yucca Mountain standard) with a pH range from 4 to 10 and initial plutonium concentration of 10-9 M. The results show that Pu(IV) sorption takes place within an hour, while the rates of Pu(V) sorption onto the colloids is much slower and mineral dependent. The kinetic results from the batch

  14. Materials to be used for radionuclide transport experiments (milestones SPL3A1M4)

    SciTech Connect

    Viani, B., LLNL

    1998-02-01

    Experiments to determine the effect of canister corrosion products on the transport of radionuclides will be undertaken using the FE(III) oxides goethite and hematite as proxies for the expected corrosion envelope that will form as a result of alteration of the corrosion allowance overpack prior to the breaching of the waste container. Samples of ESF invert concrete that have been crushed, or left intact but fractured, and that have been subjected to hydrothermal alteration will be used to determine the effect of cementitious materials on transport of radionuclides. A mixture of CaCO{sub 3}, Si0{sub 2}, and aggregate will be used as a proxy for completely carbonated concrete.

  15. Mobility of Source Zone Heavy Metals and Radionuclides: The Mixed Roles of Fermentative Activity on Fate and Transport of U and Cr. Final Report

    SciTech Connect

    Gerlach, Robin; Peyton, Brent M.; Apel, William A.

    2014-01-29

    Various U. S. Department of Energy (DOE) low and medium-level radioactive waste sites contain mixtures of heavy metals, radionuclides and assorted organic materials. In addition, there are numerous sites around the world that are contaminated with a mixture of organic and inorganic contaminants. In most sites, over time, water infiltrates the wastes, and releases metals, radionuclides and other contaminants causing transport into the surrounding environment. We investigated the role of fermentative microorganisms in such sites that may control metal, radionuclide and organics migration from source zones. The project was initiated based on the following overarching hypothesis: Metals, radionuclides and other contaminants can be mobilized by infiltration of water into waste storage sites. Microbial communities of lignocellulose degrading and fermenting microorganisms present in the subsurface of contaminated DOE sites can significantly impact migration by directly reducing and immobilizing metals and radionuclides while degrading complex organic matter to low molecular weight organic compounds. These low molecular weight organic acids and alcohols can increase metal and radionuclide mobility by chelation (i.e., certain organic acids) or decrease mobility by stimulating respiratory metal reducing microorganisms. We demonstrated that fermentative organisms capable of affecting the fate of Cr6+, U6+ and trinitrotoluene can be isolated from organic-rich low level waste sites as well as from less organic rich subsurface environments. The mechanisms, pathways and extent of contaminant transformation depend on a variety of factors related to the type of organisms present, the aqueous chemistry as well as the geochemistry and mineralogy. This work provides observations and quantitative data across multiple scales that identify and predict the coupled effects of fermentative carbon and electron flow on the transport of radionuclides, heavy metals and organic contaminants in

  16. Factors controlling radionuclide transport behavior in a generic geological radioactive waste repository

    NASA Astrophysics Data System (ADS)

    Bianchi, M.; Liu, H.; Birkholzer, J. T.

    2013-12-01

    One of the main challenges in designing a geological repository for high-level nuclear waste is the assessment of postclosure safety, which involves the long-term ability of the engineered system and the geological host formation to contain and delay the leakage of radionuclides toward the biosphere. A correct assessment requires detailed knowledge of the factors controlling radionuclide transport in the different components of the geological disposal system. For instance, molecular diffusion, which is considered the dominant transport mechanism in low-permeable geological formations, may be influenced by the heterogeneity of the diffusive parameters and by electrochemical processes. Likewise, the prevalence of advective transport in the near-field excavation damaged zone (EDZ) may be controlled by the hydrogeological conditions in the host formation, as well as by hydrogeological and geometrical properties. In this study, we performed two-dimensional numerical simulations of groundwater flow and radionuclide transport to study the influence of several factors on the prevailing transport mechanism (i.e., advection or molecular diffusion) in the different components of a geological nuclear waste repository system. Particular attention was given to the excavation damaged zone (EDZ) around the repository tunnels and access shaft, which was modeled as a single effective continuum as well as with the dual-porosity approach. We considered different hydrogeological and geometrical factors, including the ambient hydraulic gradient, the presence of groundwater pressure anomalies, and the thickness of the EDZ and its hydraulic properties. By comparing simulation results, we show that transport behavior and the role of the EDZ as a preferential flow path for radionuclide transport is most sensitive to the hydrogeological conditions in the host rock. When the hydraulic gradient in the host rock is reduced by a factor of 5 from the unit value, we observe a significant reduction

  17. The role of siderophores in the transport of radionuclides

    SciTech Connect

    Hersman, L.E.; Palmer, P.D.; Hobart, D.E.

    1993-12-31

    Iron exists in aerobic soil and water environments most commonly as insoluble Fe(III). Siderophores are powerful, microbially produced chelating agents that are used to mobilize the insoluble Fe(III) cation. Over 80 siderophores have been isolated and characterized, with some reportedly having iron-binding constants as high as 10{sup 52}. Fe(III) and Pu(IV) are similar in their charge/ionic radius ratio (4.6 and 4.2, respectively); therefore, Pu(IV) may serve as analog to Fe(III). It is possible that some radioactive wastes could be chelated by naturally occurring siderophores, thereby altering the transport rates of those elements through the subsurface environment. This investigation was initiated to investigate that possibility. The binding of {sup 239}(IV) by four chelating agents is reported in this paper: a siderophore isolated and purified from a Pseudomonas sp.; desferal, a ferrioxamine siderophore commonly used for deferration therapy; EDTA, ethylenediaminetetraacetic acid; and, citrate, trisodium salt.

  18. Colloid-Facilitated Transport of Radionuclides Through the Vadose Zone

    SciTech Connect

    Flury, Markus

    2005-06-01

    In the previous reporting period, we have clarified the qualitative mineral transformation pathways when Hanford sediments are reacted with caustic Hanford tank waste. The major finding was that cancrinite, sodalite, zeolite A and allophane form when Hanford tank waste leaks into subsurface sediments. Cancrinite and sodalite are the most stable phases. The morphology and crystallinity of the minerals formed vary with alkalinity, salinity, and the Si/Al ratio. Temperature affects the reaction rates, but not the reaction pathways. In this project period, we have further refined the reaction pathways by quantification of XRD patterns and determination of weight fractions of individual minerals. This allowed us to generalize the results as function of solution chemistry.

  19. Colloid-Facilitated Transport of Radionuclides through the Vadose Zone

    SciTech Connect

    Flury, Markus

    2005-06-01

    In the previous reporting period, we have clarified the qualitative mineral transformation pathways when Hanford sediments are reacted with caustic Hanford tank waste. The major finding was that cancrinite, sodalite, zeolite A and allophane form when Hanford tank waste leaks into subsurface sediments. Cancrinite and sodalite are the most stable phases. The morphology and crystallinity of the minerals formed vary with alkalinity, salinity, and the Si/Al ratio. Temperature affects the reaction rates, but not the reaction pathways. In this project period, we have further refined the reaction pathways by quantification of XRD patterns and determination of weight fractions of individual minerals. This allowed us to generalize the results as function of solution chemistry.

  20. Colloid-Facilitated Transport of Radionuclides Through the Vadose Zone

    SciTech Connect

    Flury, Markus

    2003-06-01

    Given that there is a wide range of chemical compositions of Hanford Tank Waste, we have studied mineral formation and transformation by systematically varying anion composition and OH concentrations of simulated tank solutions in presence and absence of Cs. The feldspathoids and zeolite formed in the presence of Cs were analyzed with X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and solid state NMR. The presence of Cs in the simulant solutions did not affect the types of minerals formed in 1 M NaOH solutions until the Cs concentration was greater than 0.1 M, a concentration that is not likely to occur in the sediment underlying the Hanford tanks. Elemental mapping indicated that incorporated Cs was homogeneously distributed in cancrinite and sodalite. High concentrations of Cs promoted the formation of highly crystalline cancrinite in hexagonal bar shape. The presence of Cs in solutions precluded the influence anions have shown in the non-cesium system. The presence of chloride anion was favorable for the formation of pure sodalite in a non-cesium solution, yet no sodalite has been found in the precipitates formed at high Cs concentration (0.5 M). Adsorption experiments indicated that Cs could access the internal parts of LTA, cancrinite and sodalite, but the diffusion appeared more difficult than that of Na and K. Cesium exchange in cancrinite and sodalite caused structural disordering of the minerals as reflected by the XRD patterns.

  1. Multicomponent mass transport model: a model for simulating migration of radionuclides in ground water

    SciTech Connect

    Washburn, J.F.; Kaszeta, F.E.; Simmons, C.S.; Cole, C.R.

    1980-07-01

    This report presents the results of the development of a one-dimensional radionuclide transport code, MMT2D (Multicomponent Mass Transport), for the AEGIS Program. Multicomponent Mass Transport is a numerical solution technique that uses the discrete-parcel-random-wald (DPRW) method to directly simulate the migration of radionuclides. MMT1D accounts for: convection;dispersion; sorption-desorption; first-order radioactive decay; and n-membered radioactive decay chains. Comparisons between MMT1D and an analytical solution for a similar problem show that: MMT1D agrees very closely with the analytical solution; MMT1D has no cumulative numerical dispersion like that associated with solution techniques such as finite differences and finite elements; for current AEGIS applications, relatively few parcels are required to produce adequate results; and the power of MMT1D is the flexibility of the code in being able to handle complex problems for which analytical solution cannot be obtained. Multicomponent Mass Transport (MMT1D) codes were developed at Pacific Northwest Laboratory to predict the movement of radiocontaminants in the saturated and unsaturated sediments of the Hanford Site. All MMT models require ground-water flow patterns that have been previously generated by a hydrologic model. This report documents the computer code and operating procedures of a third generation of the MMT series: the MMT differs from previous versions by simulating the mass transport processes in systems with radionuclide decay chains. Although MMT is a one-dimensional code, the user is referred to the documentation of the theoretical and numerical procedures of the three-dimensional MMT-DPRW code for discussion of expediency, verification, and error-sensitivity analysis.

  2. Effect of Hanford Tank Waste Leachate on Radionuclide Transport Through Unsaturated Sediment

    NASA Astrophysics Data System (ADS)

    Rod, K. A.; Serne, J. R.; Um, W.

    2006-12-01

    A series of unsaturated column experiments were conducted to investigate the effect of leaking tank waste on radionuclide transport through sediment from the Hanford site in Washington, USA. Previous studies have shown that the caustic tank leachate solution with high ionic strength (I=2-8 M NaNO3) and high pH (~14) conditions dissolves primary minerals (quartz and clays) and forms secondary precipitates on mineral surfaces. The secondary precipitates include zeolite, cancrinite and sodalite. The dissolution followed by precipitation reaction would alter the sediment pore structure as well as the soil surface properties. Both physical and chemical changes of the sediment were found to have an impact on the flow and mobility of radionuclide in unsaturated columns at varying degrees of saturation.

  3. Fukushima Daiichi–Derived Radionuclides in the Ocean: Transport, Fate, and Impacts

    NASA Astrophysics Data System (ADS)

    Buesseler, Ken; Dai, Minhan; Aoyama, Michio; Benitez-Nelson, Claudia; Charmasson, Sabine; Higley, Kathryn; Maderich, Vladimir; Masqué, Pere; Morris, Paul J.; Oughton, Deborah; Smith, John N.

    2017-01-01

    The events that followed the Tohoku earthquake and tsunami on March 11, 2011, included the loss of power and overheating at the Fukushima Daiichi nuclear power plants, which led to extensive releases of radioactive gases, volatiles, and liquids, particularly to the coastal ocean. The fate of these radionuclides depends in large part on their oceanic geochemistry, physical processes, and biological uptake. Whereas radioactivity on land can be resampled and its distribution mapped, releases to the marine environment are harder to characterize owing to variability in ocean currents and the general challenges of sampling at sea. Five years later, it is appropriate to review what happened in terms of the sources, transport, and fate of these radionuclides in the ocean. In addition to the oceanic behavior of these contaminants, this review considers the potential health effects and societal impacts.

  4. Continuous transport of Pacific-derived anthropogenic radionuclides towards the Indian Ocean

    PubMed Central

    Pittauer, Daniela; Tims, Stephen G.; Froehlich, Michaela B.; Fifield, L. Keith; Wallner, Anton; McNeil, Steven D.; Fischer, Helmut W.

    2017-01-01

    Unusually high concentrations of americium and plutonium have been observed in a sediment core collected from the eastern Lombok Basin between Sumba and Sumbawa Islands in the Indonesian Archipelago. Gamma spectrometry and accelerator mass spectrometry data together with radiometric dating of the core provide a high-resolution record of ongoing deposition of anthropogenic radionuclides. A plutonium signature characteristic of the Pacific Proving Grounds (PPG) dominates in the first two decades after the start of the high yield atmospheric tests in 1950’s. Approximately 40–70% of plutonium at this site in the post 1970 period originates from the PPG. This sediment record of transuranic isotopes deposition over the last 55 years provides evidence for the continuous long-distance transport of particle-reactive radionuclides from the Pacific Ocean towards the Indian Ocean. PMID:28304374

  5. Fukushima Daiichi-Derived Radionuclides in the Ocean: Transport, Fate, and Impacts.

    PubMed

    Buesseler, Ken; Dai, Minhan; Aoyama, Michio; Benitez-Nelson, Claudia; Charmasson, Sabine; Higley, Kathryn; Maderich, Vladimir; Masqué, Pere; Morris, Paul J; Oughton, Deborah; Smith, John N

    2017-01-03

    The events that followed the Tohoku earthquake and tsunami on March 11, 2011, included the loss of power and overheating at the Fukushima Daiichi nuclear power plants, which led to extensive releases of radioactive gases, volatiles, and liquids, particularly to the coastal ocean. The fate of these radionuclides depends in large part on their oceanic geochemistry, physical processes, and biological uptake. Whereas radioactivity on land can be resampled and its distribution mapped, releases to the marine environment are harder to characterize owing to variability in ocean currents and the general challenges of sampling at sea. Five years later, it is appropriate to review what happened in terms of the sources, transport, and fate of these radionuclides in the ocean. In addition to the oceanic behavior of these contaminants, this review considers the potential health effects and societal impacts.

  6. Continuous transport of Pacific-derived anthropogenic radionuclides towards the Indian Ocean

    NASA Astrophysics Data System (ADS)

    Pittauer, Daniela; Tims, Stephen G.; Froehlich, Michaela B.; Fifield, L. Keith; Wallner, Anton; McNeil, Steven D.; Fischer, Helmut W.

    2017-03-01

    Unusually high concentrations of americium and plutonium have been observed in a sediment core collected from the eastern Lombok Basin between Sumba and Sumbawa Islands in the Indonesian Archipelago. Gamma spectrometry and accelerator mass spectrometry data together with radiometric dating of the core provide a high-resolution record of ongoing deposition of anthropogenic radionuclides. A plutonium signature characteristic of the Pacific Proving Grounds (PPG) dominates in the first two decades after the start of the high yield atmospheric tests in 1950’s. Approximately 40–70% of plutonium at this site in the post 1970 period originates from the PPG. This sediment record of transuranic isotopes deposition over the last 55 years provides evidence for the continuous long-distance transport of particle-reactive radionuclides from the Pacific Ocean towards the Indian Ocean.

  7. Modeling the potential radionuclide transport by the Ob and Yenisey Rivers to the Kara Sea.

    PubMed

    Paluszkiewicz, T; Hibler, L F; Richmond, M C; Bradley, D J; Thomas, S A

    2001-01-01

    A major portion of the former Soviet Union (FSU) nuclear program is located in the West Siberian Basin. Among the many nuclear facilities are three production reactors and the spent nuclear fuel reprocessing sites, Mayak, Tomsk-7, and Krasnoyarsk-26, which together are probably responsible for the majority of the radioactive contamination found in the Ob and Yenisey River systems that feed into the Arctic Ocean through the Kara Sea. This manuscript describes ongoing research to estimate radionuclide fluxes to the Kara Sea from these river systems. Our approach is to apply a hierarchy of simple models that use existing and forthcoming data to quantify the transport and fate of radionuclide contaminants via various environmental pathways. We present an initial quantification of the contaminant inventory, hydrology, meteorology, and sedimentology of the Ob River system and preliminary conclusions from portions of the Ob River model.

  8. Technical Work Plan for: Near Field Environment: Engineered System: Radionuclide Transport Abstraction Model Report

    SciTech Connect

    J.D. Schreiber

    2006-12-08

    This technical work plan (TWP) describes work activities to be performed by the Near-Field Environment Team. The objective of the work scope covered by this TWP is to generate Revision 03 of EBS Radionuclide Transport Abstraction, referred to herein as the radionuclide transport abstraction (RTA) report. The RTA report is being revised primarily to address condition reports (CRs), to address issues identified by the Independent Validation Review Team (IVRT), to address the potential impact of transport, aging, and disposal (TAD) canister design on transport models, and to ensure integration with other models that are closely associated with the RTA report and being developed or revised in other analysis/model reports in response to IVRT comments. The RTA report will be developed in accordance with the most current version of LP-SIII.10Q-BSC and will reflect current administrative procedures (LP-3.15Q-BSC, ''Managing Technical Product Inputs''; LP-SIII.2Q-BSC, ''Qualification of Unqualified Data''; etc.), and will develop related Document Input Reference System (DIRS) reports and data qualifications as applicable in accordance with prevailing procedures. The RTA report consists of three models: the engineered barrier system (EBS) flow model, the EBS transport model, and the EBS-unsaturated zone (UZ) interface model. The flux-splitting submodel in the EBS flow model will change, so the EBS flow model will be validated again. The EBS transport model and validation of the model will be substantially revised in Revision 03 of the RTA report, which is the main subject of this TWP. The EBS-UZ interface model may be changed in Revision 03 of the RTA report due to changes in the conceptualization of the UZ transport abstraction model (a particle tracker transport model based on the discrete fracture transfer function will be used instead of the dual-continuum transport model previously used). Validation of the EBS-UZ interface model will be revised to be consistent with

  9. Summary of Radionuclide Reactive Transport Experiments in Fractured Tuff and Carbonate Rocks from Yucca Flat, Nevada Test Site

    SciTech Connect

    Zavarin, M; Roberts, S; Reimus, P; Johnson, M

    2006-10-11

    In the Yucca Flat basin of the Nevada Test Site (NTS), 747 shaft and tunnel nuclear detonations were conducted primarily within the tuff confining unit (TCU) or the overlying alluvium. The TCU in the Yucca Flat basin is hypothesized to inhibit radionuclide migration to the highly transmissive and regionally extensive lower carbonate aquifer (LCA) due to its wide-spread aerial extent, low permeability, and chemical reactivity. However, fast transport pathways through the TCU by way of fractures may provide a migration path for radionuclides to the LCA. Radionuclide transport in both TCU and the LCA fractures is likely to determine the location of the contaminant boundary for the Yucca Flat/Climax Mine Corrective Action Unit (CAU). Radionuclide transport through the TCU may involve both matrix and fracture flow. However, radionuclide migration over significant distances is likely to be dominated by fracture transport. Transport through the LCA will almost certainly be dominated by fracture flow, as the LCA has a very dense, low porosity matrix with very low permeability. Because of the complex nature of reactive transport in fractures, a stepwise approach to identifying mechanisms controlling radionuclide transport was used. The simplest LLNL experiments included radionuclide transport through synthetic parallel-plate fractured tuff and carbonate cores. These simplified fracture transport experiments isolated matrix diffusion and sorption effects from all other fracture transport processes (fracture lining mineral sorption, heterogeneous flow, etc.). Additional fracture transport complexity was added by performing induced fractured LCA flowthrough experiments (effect of aperture heterogeneity) or iron oxide coated parallel plate TCU flowthrough experiments (effect of fracture lining minerals). Finally naturally fractured tuff and carbonate cores were examined at LLNL and LANL. All tuff and carbonate core used in the experiments was obtained from the USGS Core Library

  10. Groundwater nanoparticles in the far-field at the Nevada Test Site: mechanism for radionuclide transport.

    PubMed

    Utsunomiya, Satoshi; Kersting, Annie B; Ewing, Rodney C

    2009-03-01

    Colloid-like nanoparticles in groundwater have been shown to facilitate migration of several radionuclides: (239,240)Pu, 137Cs, (152,154, 155)Eu, and 60Co. However, the exact type of nanoparticle and the speciation of the associated radionuclides has remained unknown. We have investigated nanoparticles sampled from the far-field at the Nevada Test Site, Nevada, utilizing advanced electron microscopytechniques, including high-angle annular dark-field scanning TEM (HAADF-STEM). Fissiogenic elements: Cs, rare earth elements (REE), activation elements: Co; and actinides: U and Th, were detected. Cesium is associated with U-forming cesium uranate with a Cs/U atomic ratio of approximately 0.12. Light REEs and Th are associated with phosphates, silicates, or apatite. Cobalt occurs as a metallic aggregate, associated with Cr, Fe, Ni, and +/-Mo. Uranyl minerals; Na-boltwoodite and oxide hydrates are also present as colloids. Because of these chemical associations with nanoscale particles, in the size range <100 nm, these particles may facilitate transport, and a variety of trace nanoscale phases may be responsible for the migration of fissiogenic and actinide elements in groundwater. To accurately model the transport of these contaminants, predictive transport models should include consideration of nanoparticle-facilitated transport.

  11. High resolution atmospheric transport modelling in support of radionuclide detections at CTBTO network

    NASA Astrophysics Data System (ADS)

    Krysta, M.; Szintai, B.; Kuśmierczyk-Michulec, J.; Carter, J. A.; Given, J. W.

    2014-12-01

    In order to support its mission of monitoring compliance with the treaty banning nuclear explosions, the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) operates four global networks of seismic, infrasound, hydroacoustic, referred to as waveform, sensors and air samplers accompanied with radionuclide detectors. The role of the International Data Centre (IDC) of CTBTO is to associate the signals detected in the monitoring networks with the physical phenomena which emitted these signals, by forming events. While the process of event building for the waveform technologies is well-established, the task of event building using the radionuclide detections remains a challenge. One of the reasons is the complexity of the process of atmospheric transport of airborne radionuclides from their sources to the detecting stations and subsequent difficulties in representing this process in models. An atmospheric transport model is driven by meteorological fields generated by numerical models coupled to observations. In addition, it is equipped with parameterisations of sub-grid scale processes to account for incompleteness of the representation of meteorological processes in the meteorological fields. In this presentation we will discuss possibilities of improving the accuracy of the atmospheric transport modelling simulations in support of radionuclide detections at CTBTO. Some of these improvements can be implemented operationally, while others, due to their computational cost, could only be performed on request. We will present the influence an increase of resolution of global meteorological fields, provided by the EMCWF (European Centre of Medium-Range Weather Forecasts), has on the quality of the simulations. We will address possible benefits of using high resolution regional meteorological fields generated with the mesoscale model WRF (Weather research and Forecasting). We will illustrate the impact of parameterisations, namely those linked to the atmospheric

  12. Modeling of U-series Radionuclide Transport Through Soil at Pena Blanca, Chihuahua, Mexico

    NASA Astrophysics Data System (ADS)

    Pekar, K. E.; Goodell, P. C.; Walton, J. C.; Anthony, E. Y.; Ren, M.

    2007-05-01

    The Nopal I uranium deposit is located at Pena Blanca in Chihuahua, Mexico. Mining of high-grade uranium ore occurred in the early 1980s, with the ore stockpiled nearby. The stockpile was mostly cleared in the 1990s; however, some of the high-grade boulders have remained there, creating localized sources of radioactivity for a period of 25-30 years. This provides a unique opportunity to study radionuclide transport, because the study area did not have any uranium contamination predating the stockpile in the 1980s. One high-grade boulder was selected for study based upon its shape, location, and high activity. The presumed drip-line off of the boulder was marked, samples from the boulder surface were taken, and then the boulder was moved several feet away. Soil samples were taken from directly beneath the boulder, around the drip-line, and down slope. Eight of these samples were collected in a vertical profile directly beneath the boulder. Visible flakes of boulder material were removed from the surficial soil samples, because they would have higher concentrations of U-series radionuclides and cause the activities in the soil samples to be excessively high. The vertical sampling profile used 2-inch thicknesses for each sample. The soil samples were packaged into thin plastic containers to minimize the attenuation and to standardize sample geometry, and then they were analyzed by gamma-ray spectroscopy with a Ge(Li) detector for Th-234, Pa-234, U-234, Th-230, Ra-226, Pb-214, Bi-214, and Pb-210. The raw counts were corrected for self-attenuation and normalized using BL-5, a uranium standard from Beaverlodge, Saskatchewan. BL-5 allowed the counts obtained on the Ge(Li) to be referenced to a known concentration or activity, which was then applied to the soil unknowns for a reliable calculation of their concentrations. Gamma ray spectra of five soil samples from the vertical profile exhibit decreasing activities with increasing depth for the selected radionuclides

  13. Sediment and radionuclide transport in rivers. Phase 2. Field sampling program for Cattaraugus and Buttermilk Creeks, New York

    SciTech Connect

    Walters, W.H.; Ecker, R.M.; Onishi, Y.

    1982-04-01

    As part of a study on sediment and radionuclide transport in rivers, Pacific Northwest Laboratory (PNL) is investigating the effect of sediment on the transport of radionuclides in Cattaraugus and Buttermilk Creeks, New York. A source of radioactivity in these creeks is the Western New York Nuclear Service Center which consists of a low-level waste disposal site and a nuclear fuel reprocessing plant. Other sources of radioactivity include fallout from worldwide weapons testing and natural background radioactivity. The major objective of the PNL Field Sampling Program is to provide data on sediment and radionuclide characteristics in Cattaraugus and Buttermilk Creeks to verify the use of the Sediment and Radionuclide Transport model, SERATRA, for nontidal rivers. This report covers the results of field data collection conducted during September 1978. Radiological analysis of sand, silt, and clay size fractions of suspended and bed sediment, and water were performed. Results of these analyses indicate that the principal radionuclides occurring in these two water courses, with levels significantly higher than background levels, during the Phase 2 sampling program were Cesium-137 and Strontium-90. These radionuclides had significantly higher activity levels above background in the bed sediment, suspended sediment, and water samples. Other radionuclides that are possibly being released into the surface water environment by the Nuclear Fuel Services facilities are Plutonium-238, 239, and 240, Americium-241, Curium-244, and Tritium. More radionuclides were consistently found in the bed sediment as compared to suspended sediment. The fewest radionuclides were found in the water of Buttermilk and Cattaraugus Creeks. The higher levels were found in the bed sediments for the gamma-emitters and in the suspended sediment for the alpha and beta-emitters (not including Tritium).

  14. Transport and fate of radionuclides in aquatic environments--the use of ecosystem modelling for exposure assessments of nuclear facilities.

    PubMed

    Kumblad, L; Kautsky, U; Naeslund, B

    2006-01-01

    In safety assessments of nuclear facilities, a wide range of radioactive isotopes and their potential hazard to a large assortment of organisms and ecosystem types over long time scales need to be considered. Models used for these purposes have typically employed approaches based on generic reference organisms, stylised environments and transfer functions for biological uptake exclusively based on bioconcentration factors (BCFs). These models are of non-mechanistic nature and involve no understanding of uptake and transport processes in the environment, which is a severe limitation when assessing real ecosystems. In this paper, ecosystem models are suggested as a method to include site-specific data and to facilitate the modelling of dynamic systems. An aquatic ecosystem model for the environmental transport of radionuclides is presented and discussed. With this model, driven and constrained by site-specific carbon dynamics and three radionuclide specific mechanisms: (i) radionuclide uptake by plants, (ii) excretion by animals, and (iii) adsorption to organic surfaces, it was possible to estimate the radionuclide concentrations in all components of the modelled ecosystem with only two radionuclide specific input parameters (BCF for plants and Kd). The importance of radionuclide specific mechanisms for the exposure to organisms was examined, and probabilistic and sensitivity analyses to assess the uncertainties related to ecosystem input parameters were performed. Verification of the model suggests that this model produces analogous results to empirically derived data for more than 20 different radionuclides.

  15. CASCADER: An M-chain gas-phase radionuclide transport and fate model. Volume 4 -- Users guide to CASCADR9

    SciTech Connect

    Cawlfield, D.E.; Emer, D.F.; Lindstrom, F.T.; Shott, G.J.

    1993-09-01

    Chemicals and radionuclides move either in the gas-phase, liquid-phase, or both phases in soils. They may be acted upon by either biological or abiotic processes through advection and/or dispersion. Additionally during the transport of parent and daughter radionuclides in soil, radionuclide decay may occur. This version of CASCADER called CASCADR9 starts with the concepts presented in volumes one and three of this series. For a proper understanding of how the model works, the reader should read volume one first. Also presented in this volume is a set of realistic scenarios for buried sources of radon gas, and the input and output file structure for CASCADER9.

  16. Wind Transport of Radionuclide- Bearing Dust, Peña Blanca, Chihuahua, Mexico

    NASA Astrophysics Data System (ADS)

    Velarde, R.; Goodell, P. C.; Gill, T. E.; Arimoto, R.

    2007-05-01

    This investigation evaluates radionuclide fractionation during wind erosion of high-grade uranium ore storage piles at Peña Blanca (50km north of Chihuahua City), Chihuahua, Mexico. The aridity of the local environment promotes dust resuspension by high winds. Although active operations ceased in 1983, the Peña Blanca mining district is one of Mexico`s most important uranium ore reserves. The study site contains piles of high grade ore, left loose on the surface, and separated by the specific deposits from which they were derived (Margaritas, Nopal I, and Puerto I). Similar locations do not exist in the United States, since uranium mining sites in the USA have been reclaimed. The Peña Blanca site serves as an analog for the Yucca Mountain project. Dust deposition is collected at Peña Blanca with BSNE sediment catchers (Fryrear, 1986) and marble dust traps (Reheis, 1999). These devices capture windblown sediment; subsequently, the sample data will help quantify potentially radioactive short term field sediment loss from the repository surface and determine sediment flux. Aerosols and surface materials will be analyzed and radioactivity levels established utilizing techniques such as gamma spectroscopy. As a result, we will be able to estimate how much radionuclide contaminated dust is being transported or attached geochemically to fine grain soils or minerals (e.g., clays or iron oxides). The high-grade uranium-bearing material is at secular equilibrium, thus the entire decay series is present. Of resulting interest is not only the aeolian transport of uranium, but also of the other daughter products. These studies will improve our understanding of geochemical cycling of radionuclides with respect to sources, transport, and deposition. The results may also have important implications for the geosciences and homeland security, and potential applications to public health. Funding for this project is provided in part via a NSF grant to Arimoto.

  17. TERRA: a computer code for simulating the transport of environmentally released radionuclides through agriculture

    SciTech Connect

    Baes, C.F. III; Sharp, R.D.; Sjoreen, A.L.; Hermann, O.W.

    1984-11-01

    TERRA is a computer code which calculates concentrations of radionuclides and ingrowing daughters in surface and root-zone soil, produce and feed, beef, and milk from a given deposition rate at any location in the conterminous United States. The code is fully integrated with seven other computer codes which together comprise a Computerized Radiological Risk Investigation System, CRRIS. Output from either the long range (> 100 km) atmospheric dispersion code RETADD-II or the short range (<80 km) atmospheric dispersion code ANEMOS, in the form of radionuclide air concentrations and ground deposition rates by downwind location, serves as input to TERRA. User-defined deposition rates and air concentrations may also be provided as input to TERRA through use of the PRIMUS computer code. The environmental concentrations of radionuclides predicted by TERRA serve as input to the ANDROS computer code which calculates population and individual intakes, exposures, doses, and risks. TERRA incorporates models to calculate uptake from soil and atmospheric deposition on four groups of produce for human consumption and four groups of livestock feeds. During the environmental transport simulation, intermediate calculations of interception fraction for leafy vegetables, produce directly exposed to atmospherically depositing material, pasture, hay, and silage are made based on location-specific estimates of standing crop biomass. Pasture productivity is estimated by a model which considers the number and types of cattle and sheep, pasture area, and annual production of other forages (hay and silage) at a given location. Calculations are made of the fraction of grain imported from outside the assessment area. TERRA output includes the above calculations and estimated radionuclide concentrations in plant produce, milk, and a beef composite by location.

  18. Imaging, Mapping and Monitoring Environmental Radionuclide Transport Using Compton-Geometry Gamma Camera

    NASA Astrophysics Data System (ADS)

    Bridge, J. W.; Dormand, J.; Cooper, J.; Judson, D.; Boston, A. J.; Bankhead, M.; Onda, Y.

    2014-12-01

    The legacy to-date of the nuclear disaster at Fukushima Dai-ichi, Japan, has emphasised the fundamental importance of high quality radiation measurements in soils and plant systems. Current-generation radiometers based on coded-aperture collimation are limited in their ability to locate sources of radiation in three dimensions, and require a relatively long measurement time due to the poor efficiency of the collimation system. The quality of data they can provide to support biogeochemical process models in such systems is therefore often compromised. In this work we report proof-of-concept experiments demonstrating the potential of an alternative approach in the measurement of environmentally-important radionuclides (in particular 137Cs) in quartz sand and soils from the Fukushima exclusion zone. Compton-geometry imaging radiometers harness the scattering of incident radiation between two detectors to yield significant improvements in detection efficiency, energy resolution and spatial location of radioactive sources in a 180° field of view. To our knowledge we are reporting its first application to environmentally-relevant systems at low activity, dispersed sources, with significant background radiation and, crucially, movement over time. We are using a simple laboratory column setup to conduct one-dimensional transport experiments for 139Ce and 137Cs in quartz sand and in homogenized repacked Fukushima soils. Polypropylene columns 15 cm length with internal diameter 1.6 cm were filled with sand or soil and saturated slowly with tracer-free aqueous solutions. Radionuclides were introduced as 2mL pulses (step-up step-down) at the column inlet. Data were collected continuously throughout the transport experiment and then binned into sequential time intervals to resolve the total activity in the column and its progressive movement through the sand/soil. The objective of this proof-of-concept work is to establish detection limits, optimise image reconstruction

  19. Final Technical Report: Viral Infection of Subsurface Microorganisms and Metal/Radionuclide Transport

    SciTech Connect

    Weber, Karrie A.; Bender, Kelly S.; Li, Yusong

    2013-09-28

    Microbially mediated metabolisms have been identified as a significant factor either directly or indirectly impacting the fate and transport of heavy metal/radionuclide contaminants. To date microorganisms have been isolated from contaminated environments. Examination of annotated finished genome sequences of many of these subsurface isolates from DOE sites, revealed evidence of prior viral infection. To date the role that viruses play influencing microbial mortality and the resulting community structure which directly influences biogeochemical cycling in soils and sedimentary environments remains poorly understood. The objective of this exploratory study was to investigate the role of viral infection of subsurface bacteria and the formation of contaminant-bearing viral particles. This objective was approached by examining the following working hypotheses: (i) subsurface microorganisms are susceptible to viral infections by the indigenous subsurface viral community, and (ii) viral surfaces will adsorb heavy metals and radionuclides. Our results have addressed basic research needed to accomplish the BER Long Term Measure to provide sufficient scientific understanding such that DOE sites would be able to incorporate coupled physical, chemical and biological processes into decision making for environmental remediation or natural attenuation and long-term stewardship by establishing viral-microbial relationships on the subsequent fate and transport of heavy metals and radionuclides. Here we demonstrated that viruses play a significant role in microbial mortality and community structure in terrestrial subsurface sedimentary systems. The production of viral-like particles within subsurface sediments in response to biostimulation with dissolved organic carbon and a terminal electron acceptor resulted in the production of viral-like particles. Organic carbon alone did not result in significant viral production and required the addition of a terminal electron acceptor

  20. Modelling radionuclide transport in fractured media with a dynamic update of Kd values

    DOE PAGES

    Trinchero, Paolo; Painter, Scott L.; Ebrahimi, Hedieh; ...

    2015-10-13

    Radionuclide transport in fractured crystalline rocks is a process of interest in evaluating long term safety of potential disposal systems for radioactive wastes. Given their numerical efficiency and the absence of numerical dispersion, Lagrangian methods (e.g. particle tracking algorithms) are appealing approaches that are often used in safety assessment (SA) analyses. In these approaches, many complex geochemical retention processes are typically lumped into a single parameter: the distribution coefficient (Kd). Usually, the distribution coefficient is assumed to be constant over the time frame of interest. However, this assumption could be critical under long-term geochemical changes as it is demonstrated thatmore » the distribution coefficient depends on the background chemical conditions (e.g. pH, Eh, and major chemistry). In this study, we provide a computational framework that combines the efficiency of Lagrangian methods with a sound and explicit description of the geochemical changes of the site and their influence on the radionuclide retention properties.« less

  1. Long-term groundwater transport of radionuclides from seepage basins at the Savannah River Site

    NASA Astrophysics Data System (ADS)

    Wiedmer, A.; Hunt, J. R.; Spycher, N.; Denham, M. E.

    2009-12-01

    The Savannah River Site (SRS) in South Carolina produced tritium and plutonium between 1953 and the beginning of the 1990s. The site released process wastewater containing plutonium, tritium, uranium, and fission products into seepage basins with the intent that short half-life radionuclides would decay in the years required for the groundwater to transport the waste materials to surface waters and that activity levels in the surface waters would not exceed levels considered appropriate in the 1950s. Between 1955 and 1988, the process operations at the F-area lead to the discharge of more than 12×106 cubic meters of low-level liquid radioactive waste solutions into unlined seepage basins. The waste contained longer half life nuclides that did not significantly decay during groundwater transit such as 3H (t½ = 12.28 years), 90Sr (t½ = 28.6 years), 99Tc (t½ = 2.13×105 years) and 129I (t½ = 1.57×107 years). Remediation started with the capping of the basin in 1990 followed by active plume pumping between 1997 and 2003. In 2004 a groundwater barrier was installed and in situ pH neutralization started in 2005. Tritium monitoring detected migration to Four Mile Creek by the end of the 1950s. Other radionuclides such as 90Sr, 99Tc and 129I have also been detected in groundwater seeping into the creek, and tritium levels and conductivity were well correlated at the seepage line. The seepage basin contaminated groundwater plume surfaced at seepage faces near a creek with a pH of 3. This acidity combined with high ionic strengths associated with nitrate mobilized contaminants such as 90Sr. The high levels of tritium, low pH and high conductivity at the seepage line show the likely importance of density driven flow for the salts of the plume and the limited dilution by groundwater flow. The Savannah River Site requires remediation to minimize radionuclide migration off-site, and there has been an extensive monitoring program of process waste discharges, groundwater

  2. Comparison of one-, two-, and three-dimensional models for mass transport of radionuclides

    SciTech Connect

    Prickett, T.A.; Voorhees, M.L.; Herzog, B.L.

    1980-02-01

    This technical memorandum compares one-, two-, and three-dimensional models for studying regional mass transport of radionuclides in groundwater associated with deep repository disposal of high-level radioactive wastes. In addition, this report outlines the general conditions for which a one- or two-dimensional model could be used as an alternate to a three-dimensional model analysis. The investigation includes a review of analytical and numerical models in addition to consideration of such conditions as rock and fluid heterogeneity, anisotropy, boundary and initial conditions, and various geometric shapes of repository sources and sinks. Based upon current hydrologic practice, each review is taken separately and discussed to the extent that the researcher can match his problem conditions with the minimum number of model dimensions necessary for an accurate solution.

  3. Radionuclide transport from yucca Mountain and Inter-basin Flow in Death Valley

    SciTech Connect

    Bredehoeft, J.; Fridrich, C.; King, C.HG.M.

    2007-07-01

    Hydrodynamics and the U.S. Geological survey conducted studies to evaluate far-field issues related to potential transport, by ground water, of radionuclide into Inyo County from Yucca Mountain, including Death Valley, and the evaluation of a connection between the Lower Carbonate Aquifer (LCA) and the biosphere. Our oversight and completed Cooperative Agreement research, and a number of other investigators research indicate that there is groundwater flow between the alluvial and carbonate aquifers both at Yucca Mountain and in Inyo County. The specific purpose of our research was to acquire geological, subsurface geology, and hydrologic data to: 1. Establish the existence of inter-basin flow between the Amargosa Basin and Death Valley Basin, 2. Characterize groundwater flow paths in the LCA through Southern Funeral Mountain Range, and 3. Evaluate the hydraulic connection between the Yucca Mountain repository and the major springs in Death Valley through the LCA. 4. Evaluate the hydraulic connection between the Yucca Mountain repository and Franklin Lake Playa. The hydraulic characterization of the LCA is of critical interest to Inyo County and the U.S. Department of Energy because: 1. The upward gradient in the LCA at Yucca Mountain provides a natural barrier to radionuclide transport, 2. The LCA is a necessary habitat resource for the endangered Devil's Hole pup fish, and 3. The LCA is the primary water supply and source of water to the major springs in Death Valley National Park. This paper presents the results of our study program to evaluate if inter-basin flow exists between the Amargosa and Death Valley Basins through the LCA. The study presents the results of our structural geology analysis of the Southern Funeral Mountain range, geochemical source analysis of spring waters in the region, and a numerical groundwater model to simulate inter-basin flow in the Southern Funeral Mountain range. (authors)

  4. Hydrologic Processes Controlling the Transport of Radionuclides Through the Hanford Vadose Zone

    NASA Astrophysics Data System (ADS)

    Mayes, M. A.; Jardine, P. M.; Pace, M. N.; Fendorf, S. E.; Mehlhorn, T. L.; Roh, Y.; Ladd, J. L.; Bjornstad, B. N.

    2001-12-01

    At the U.S. Department of Energy's Hanford Reservation in south central Washington, accelerated migration of radionuclides has been observed in the vadose zone beneath the Hanford Tank Farms. The goal of this research was to provide an improved understanding and predictive capability of the coupled hydrological and geochemical mechanisms that are responsible for contaminant mobility in the vadose zone. The research strategy consisted of collecting undisturbed sediment cores (0.3 m diameter x 0.3 m length) in order to perform laboratory-scale, multiple nonreactive and reactive transport experiments at a variety of different water contents. Cores were collected from the Miocene-Pliocene age Upper Ringold Formation, which consists of fine sand, silt and clay. Cores were acquired both parallel and perpendicular to bedding. Two units within the U. Ringold were sampled, a horizontally-bedded, laminated Upper Silt and a cross-bedded Lower Silty Sand. Unsaturated transport experiments were performed using the nonreactive tracers Br-, PFBA, and PIPES, which differ in their free-water molecular diffusion coefficients. Unsaturated transport experiments through cores with discontinuous layering resulted in the formation of an unstable wetting front characterized by preferential finger flow and the development of zones of perched water. Media bypass is inferred by early breakthrough of tracers relative to saturated flow, while the presence of perched water is suggested by decreasing core matric potential. Further, observed separation of tracers (Br-> PFBA > PIPES) suggests that diffusional processes can contribute to contaminant transport. Conversely, transport through cores composed of laterally continuous beds did not result in preferential flow, the development of perched water, or tracer separation regardless of saturation. This suggests a propensity for lateral flow beneath the tank farms. Preferential vertical finger flow may be initiated by intersection with lithologic

  5. Coupling Seepage and Radionuclide Transport in and Around Emplacement Drifts at Yucca Mountain

    NASA Astrophysics Data System (ADS)

    Zhang, G.; Spycher, N.; Sonnenthal, E.; Steefel, C.

    2007-12-01

    The proposed nuclear waste repository of the United States is located at Yucca Mountain, Nevada. Waste packages will be placed in deep (~350 m) underground drifts in volcanic tuff. Seepage may potentially occur at the repository drifts when the drifts get rewetted after a dryout period. The potential seepage water will be quickly evaporated or boiled to near dryness as long as it falls on the top of the hot waste package leading to formation of brine, precipitation of salts and volatilization of gases. These processes may potentially impact the long-term safety of waste packages in the drift. The objectives of this study are to: (1) develop a quantitative model of coupled thermal, hydrological, and chemical (THC) processes potentially leading to brine formation, salt precipitation and gas volatilization on top of waste packages and/or a drip shield and (2) dynamically integrate such a model into the larger-scale models of processes within and around waste emplacement drifts, as well as into the smaller-scale waste-package corrosion models. Process models were implemented into an existing reactive transport numerical simulator, TOUGHREACT, to allow modeling of (1) evaporative concentration to very high ionic strength (up to 40 molal), (2) boiling point elevation due to dissolved salts, (3) boiling/evaporation to dryness, and (4) salt deliquescence. An integrated near-field and in-drift THC simulation was run using a vertical 2-D grid extending from near the ground surface to the groundwater table, and covering a width equal to half the design drift spacing of 81 m. The integrated model was then used to simulate a discrete dripping event within the drift. The model considered the release of radionuclides into seepage water as this water contacts the waste package and flows through the invert. The precipitation of uranophane and Np-uranophane was also considered. These minerals form in the invert from the neutralization of mildly acidic seepage water by clay minerals

  6. The Atmospheric Radionuclide Transport Model (ARTM) - Validation of a long-term atmospheric dispersion model

    NASA Astrophysics Data System (ADS)

    Hettrich, Sebastian; Wildermuth, Hans; Strobl, Christopher; Wenig, Mark

    2016-04-01

    In the last couple of years, the Atmospheric Radionuclide Transport Model (ARTM) has been developed by the German Federal Office for Radiation Protection (BfS) and the Society for Plant and Reactor Security (GRS). ARTM is an atmospheric dispersion model for continuous long-term releases of radionuclides into the atmosphere, based on the Lagrangian particle model. This model, developed in the first place as a more realistic replacement for the out-dated Gaussian plume models, is currently being optimised for further scientific purposes to study atmospheric dispersion in short-range scenarios. It includes a diagnostic wind field model, allows for the application of building structures and multiple sources (including linear, 2-and 3-dimensional source geometries), and considers orography and surface roughness. As an output it calculates the activity concentration, dry and wet deposition and can model also the radioactive decay of Rn-222. As such, ARTM requires to undergo an intense validation process. While for short-term and short-range models, which were mainly developed for examining nuclear accidents or explosions, a few measurement data-sets are available for validation, data-sets for validating long-term models are very sparse and the existing ones mostly prove to be not applicable for validation. Here we present a strategy for the validation of long-term Lagrangian particle models based on the work with ARTM. In our validation study, the first part we present is a comprehensive analysis of the model sensitivities on different parameters like e.g. (simulation grid size resolution, starting random number, amount of simulation particles, etc.). This study provides a good estimation for the uncertainties of the simulation results and consequently can be used to generate model outputs comparable to the available measurements data at various distances from the emission source. This comparison between measurement data from selected scenarios and simulation results

  7. A groundwater flow and transport model of long-term radionuclide migration in central Frenchman flat, Nevada test site

    SciTech Connect

    Kwicklis, Edward Michael; Becker, Naomi M; Ruskauff, Gregory; De Novio, Nicole; Wilborn, Bill

    2010-11-10

    A set of groundwater flow and transport models were created for the Central Testing Area of Frenchman Flat at the former Nevada Test Site to investigate the long-term consequences of a radionuclide migration experiment that was done between 1975 and 1990. In this experiment, radionuclide migration was induced from a small nuclear test conducted below the water table by pumping a well 91 m away. After radionuclides arrived at the pumping well, the contaminated effluent was discharged to an unlined ditch leading to a playa where it was expected to evaporate. However, recent data from a well near the ditch and results from detailed models of the experiment by LLNL personnel have convincingly demonstrated that radionuclides from the ditch eventually reached the water table some 220 m below land surface. The models presented in this paper combine aspects of these detailed models with concepts of basin-scale flow to estimate the likely extent of contamination resulting from this experiment over the next 1,000 years. The models demonstrate that because regulatory limits for radionuclide concentrations are exceeded only by tritium and the half-life of tritium is relatively short (12.3 years), the maximum extent of contaminated groundwater has or will soon be reached, after which time the contaminated plume will begin to shrink because of radioactive decay. The models also show that past and future groundwater pumping from water supply wells within Frenchman Flat basin will have negligible effects on the extent of the plume.

  8. Developing of Watershed Radionuclide Transport Model DHSVM-R as Modification and Extension of Distributed Hydrological and Sediment Dynamics Model DHSVM

    NASA Astrophysics Data System (ADS)

    Zheleznyak, M.; Kivva, S.; Onda, Y.; Nanba, K.; Wakiyama, Y.; Konoplev, A.

    2015-12-01

    The reliable modeling tools for prediction wash - off radionuclides from watersheds are needed as for assessment the consequences of accidental and industrial releases of radionuclides, as for soil erosion studies using the radioactive tracers. The distributed model of radionuclide transport through watershed in exchangeable and nonexchangeable forms in solute and with sediments was developed and validated for small Chernobyl watersheds in 90th within EU SPARTACUS project (van der Perk et al., 1996). New tendency is coupling of radionuclide transport models and the widely validated hydrological distributed models. To develop radionuclide transport model DHSVM-R the open source Distributed Hydrology Soil Vegetation Model -DHSVM http://www.hydro.washington.edu/Lettenmaier/Models/DHSVM was modified and extended. The main changes provided in the hydrological and sediment transport modules of DHSVM are as follows: Morel-Seytoux infiltration model is added; four-directions schematization for the model's cells flows (D4) is replaced by D8 approach; the finite-difference schemes for solution of kinematic wave equations for overland water flow, stream net flow, and sediment transport are replaced by new computationally efficient scheme. New radionuclide transport module, coupled with hydrological and sediment transport modules, continues SPARTACUS's approach, - it describes radionuclide wash-off from watershed and transport via stream network in soluble phase and on suspended sediments. The hydrological module of DHSVM-R was calibrated and validated for the watersheds of Ukrainian Carpathian mountains and for the subwatersheds of Niida river flowing 137Cs in solute and with suspended sediments to Pacific Ocean at 30 km north of the Fukushima Daiichi NPP. The modules of radionuclide and sediment transport were calibrated and validated versus experimental data for USLE experimental plots in Fukushima Prefecture and versus monitoring data collected in Niida watershed. The role

  9. IN-SITU RADIONUCLIDE TRANSPORT NEAR THE NOPAL I URANIUM DEPOSIT AT PENA BLANCA, MEXICO: CONSTRAINTS FROM SHORT-LIVED DECAY-SERIES RADIONUCLIDES

    SciTech Connect

    S. Luo; T.L. Ku; V. Todd; M. Murrell; J. Alfredo Rodriguez Pineda; J. Dinsmoor; A. Mitchell

    2005-07-11

    For nuclear waste management, an important mechanism by which radioactive waste components are isolated from returning to the human environment, the biosphere, is by the geological barrier in which the effectiveness of the barrier is characterized by in-situ retardation factor, i.e., the transport rate of a radionuclide relative to that of groundwater. As part of natural analog studies of the Yucca Mountain Project of the U. S. Department of Energy, we propose such characterization by using naturally-occurring decay-series radioisotopes as an analog. We collected large-volume (>1000 liters) groundwater samples from three wells (PB, Pozos, and PB4, respectively) near the Nopal I Uranium Ore site at Pena Blanca, Mexico, by using an in-situ Mn-cartridge filtration technique for analysis of short-lived decay-series radionuclides. Results show that the activities of short-lived radioisotopes ({sup 228}Ra, {sup 224}Ra and {sup 223}Ra) and activity ratios of {sup 224}Ra/{sup 228}Ra and {sup 224}Ra/{sup 223}Ra are higher at PB and Pozos than at PB4. In contrast, the {sup 210}Po activity is much lower at PB and Pozos than at PB4. The high Ra activities and activities ratios at PB and Pozos are attributable to the high alpha-recoil input from the aquifer rocks, while the high {sup 210}Po activity at PB4 is due to the enhanced colloidal transport. Based on a uranium-series transport model, we estimate that the in-situ retardation factor of Ra is (0.43 {+-} 0.02) x 10{sup 3} at PB, (1.68 {+-} 0.08) x 10{sup 3} at Pozos, and (1.19 {+-} 0.08) x 10{sup 3} at PB4 and that the mean fracture width in the aquifer rocks is about 0.23 {micro}m at PB, 0.37 {micro}m at Posos, and 4.0 {micro}m at PB4, respectively. The large fracture width at PB4 as derived from the model provides an additional evidence to the inference from the Po measurements that particle-reactive radionuclides are transported mainly as colloidal forms through the large fractures in rocks. Our model also suggests that

  10. Scale-Dependent Fracture-Matrix Interactions And Their Impact on Radionuclide Transport - Final Report

    SciTech Connect

    Detwiler, Russell

    2014-06-30

    Matrix diffusion and adsorption within a rock matrix are widely regarded as important mechanisms for retarding the transport of radionuclides and other solutes in fractured rock (e.g., Neretnieks, 1980; Tang et al., 1981; Maloszewski and Zuber, 1985; Novakowski and Lapcevic, 1994; Jardine et al., 1999; Zhou and Xie, 2003; Reimus et al., 2003a,b). When remediation options are being evaluated for old sources of contamination, where a large fraction of contaminants reside within the rock matrix, slow diffusion out of the matrix greatly increases the difficulty and timeframe of remediation. Estimating the rates of solute exchange between fractures and the adjacent rock matrix is a critical factor in quantifying immobilization and/or remobilization of DOE-relevant contaminants within the subsurface. In principle, the most rigorous approach to modeling solute transport with fracture-matrix interaction would be based on local-scale coupled advection-diffusion/dispersion equations for the rock matrix and in discrete fractures that comprise the fracture network (Discrete Fracture Network and Matrix approach, hereinafter referred to as DFNM approach), fully resolving aperture variability in fractures and matrix property heterogeneity. However, such approaches are computationally demanding, and thus, many predictive models rely upon simplified models. These models typically idealize fracture rock masses as a single fracture or system of parallel fractures interacting with slabs of porous matrix or as a mobile-immobile or multi-rate mass transfer system. These idealizations provide tractable approaches for interpreting tracer tests and predicting contaminant mobility, but rely upon a fitted effective matrix diffusivity or mass-transfer coefficients. However, because these fitted parameters are based upon simplified conceptual models, their effectiveness at predicting long-term transport processes remains uncertain. Evidence of scale dependence of effective matrix diffusion

  11. Modeling the Hydrogeochemical Transport of Radionuclides through Engineered Barriers System in the Proposed LLW Disposal Site of Taiwan - 12082

    SciTech Connect

    Lin, Wen-Sheng; Liu, Chen-Wuing; Tsao, Jui-Hsuan; Li, Ming-Hsu

    2012-07-01

    A proposed site for final disposal of low-level radioactive waste located in Daren Township of Taitung County along the southeastern coast has been on the selected list in Taiwan. The geology of the Daren site consists of argillite and meta-sedimentary rocks. A mined cavern design with a tunnel system of 500 m below the surface is proposed. Concrete is used as the main confinement material for the engineered barrier. To investigate the hydrogeochemical transport of radionuclides through engineered barriers system, HYDROGEOCHEM5.0 model was applied to simulate the complex chemical interactions among radionuclides, the cement minerals of the concrete, groundwater flow, and transport in the proposed site. The simulation results showed that the engineered barriers system with the side ditch efficiently drained the ground water and lowered the concentration of the concrete degradation induced species (e.g., hydrogen ion, sulfate, and chloride). The velocity of groundwater observed at side ditch gradually decreased with time due to the fouling of pore space by the mineral formation of ettringite and thaumasite. The short half-life of Co-60, Sr-90 and Cs-137 significantly reduced the concentrations, whereas the long half-life of I-129(1.57x10{sup 7} years) and Am-241(432 years) remain stable concentrations at the interface of waste canister and concrete barrier after 300 years. The mineral saturation index (SI) was much less than zero due to the low aqueous concentration of radionuclide, so that the precipitation formation of Co-60, Sr-90, I-129, Cs-137 and Am-241 related minerals were not found. The effect of adsorption/desorption (i.e., surface complexation model) could be a crucial geochemical mechanism for the modeling of liquid-solid phase behavior of radionuclide in geochemically dynamic environments. Moreover, the development of advanced numerical models that are coupled with hydrogeochemical transport and dose assessment of radionuclide is required in the future

  12. RADTRAD: A simplified model for RADionuclide Transport and Removal And Dose estimation

    SciTech Connect

    Humphreys, S.L.; Miller, L.A.; Monroe, D.K.; Heames, T.J.

    1998-04-01

    This report documents the RADTRAD computer code developed for the U.S. Nuclear Regulatory Commission (NRC) Office of Nuclear Reactor Regulation (NRR) to estimate transport and removal of radionuclides and dose at selected receptors. The document includes a users` guide to the code, a description of the technical basis for the code, the quality assurance and code acceptance testing documentation, and a programmers` guide. The RADTRAD code can be used to estimate the containment release using either the NRC TID-14844 or NUREG-1465 source terms and assumptions, or a user-specified table. In addition, the code can account for a reduction in the quantity of radioactive material due to containment sprays, natural deposition, filters, and other natural and engineered safety features. The RADTRAD code uses a combination of tables and/or numerical models of source term reduction phenomena to determine the time-dependent dose at user-specified locations for a given accident scenario. The code system also provides the inventory, decay chain, and dose conversion factor tables needed for the dose calculation. The RADTRAD code can be used to assess occupational radiation exposures, typically in the control room; to estimate site boundary doses; and to estimate dose attenuation due to modification of a facility or accident sequence.

  13. Monitoring radionuclide and suspended-sediment transport in the Little Colorado River basin, Arizona and New Mexico, USA

    USGS Publications Warehouse

    Gray, John R.; Fisk, Gregory G.

    1992-01-01

    From July 1988 through September 1991, radionuclide and suspended-sediment transport were monitored in ephemeral streams in the semiarid Little Colorado River basin of Arizona and New Mexico, USA, where in-stream gross-alpha plus gross-beta activities have exceeded Arizona's Maximum Allowable Limit through releases from natural weathering processes and from uranium-mining operations in the Church Rock Mining District, Grants Mineral Belt, New Mexico. Water samples were collected at a network of nine continuous-record streamgauges equipped with microprocessor-based satellite telemetry and automatic water-sampling systems, and six partial-record streamgauges equipped with passive water samplers. Analytical results from these samples were used to calculate transport of selected suspended and dissolved radionuclides in the uranium-238 and thorium-232 decay series.

  14. The use of a heterogeneity-based isotherm to interpret the transport of reactive radionuclides in volcanic tuff media

    SciTech Connect

    Polzer, W.L.; Fuentes, H.R.

    1987-12-31

    The sorption of cesium and strontium has been modeled with a heterogeneity-based isotherm equation for various tuff materials including those within a sequence of geologic stratigraphic units. The theory of the isotherm foresees the relative retardation and the chemical dispersion of the studied radionuclides during transport. The concepts of heterogeneity of sites and variability in the maximum number of sites available for sorption are incorporated into the model. 16 refs., 4 figs., 3 tabs.

  15. Use of Transportable Radiation Detection Instruments to Assess Internal Contamination from Intakes of Radionuclides Part II: Calibration Factors and ICAT Computer Program.

    PubMed

    Anigstein, Robert; Olsher, Richard H; Loomis, Donald A; Ansari, Armin

    2016-12-01

    The detonation of a radiological dispersion device or other radiological incidents could result in widespread releases of radioactive materials and intakes of radionuclides by affected individuals. Transportable radiation monitoring instruments could be used to measure radiation from gamma-emitting radionuclides in the body for triaging individuals and assigning priorities to their bioassay samples for in vitro assessments. The present study derived sets of calibration factors for four instruments: the Ludlum Model 44-2 gamma scintillator, a survey meter containing a 2.54 × 2.54-cm NaI(Tl) crystal; the Captus 3000 thyroid uptake probe, which contains a 5.08 × 5.08-cm NaI(Tl) crystal; the Transportable Portal Monitor Model TPM-903B, which contains two 3.81 × 7.62 × 182.9-cm polyvinyltoluene plastic scintillators; and a generic instrument, such as an ionization chamber, that measures exposure rates. The calibration factors enable these instruments to be used for assessing inhaled or ingested intakes of any of four radionuclides: Co, I, Cs, and Ir. The derivations used biokinetic models embodied in the DCAL computer software system developed by the Oak Ridge National Laboratory and Monte Carlo simulations using the MCNPX radiation transport code. The three physical instruments were represented by MCNP models that were developed previously. The affected individuals comprised children of five ages who were represented by the revised Oak Ridge National Laboratory pediatric phantoms, and adult men and adult women represented by the Adult Reference Computational Phantoms described in Publication 110 of the International Commission on Radiological Protection. These calibration factors can be used to calculate intakes; the intakes can be converted to committed doses by the use of tabulated dose coefficients. These calibration factors also constitute input data to the ICAT computer program, an interactive Microsoft Windows-based software package that estimates intakes of

  16. Radionuclide-Chelating Agent Complexes in Low-Level Radioactive Decontamination Waste; Stability, Adsorption and Transport Potential

    SciTech Connect

    Serne, R. Jeffrey; Cantrell, Cantrell J.; Lindenmeier, Clark W.; Owen, Antionette T.; Kutnyakov, Igor V.; Orr, Robert D.; Felmy, Andrew R.

    2002-02-01

    Speciation calculations were done to determine whether organic complexants facilitate transport of radionuclides leached from waste buried in soils. EDTA readily mobilizes divalent transition metals and moderately impacts trivalent actinides. Picolinate readily mobilizes only Ni2+ and Co2+. These speciation predictions ignore the influence of soil adsorption and biodegradation that break apart the complexes. In adsorption studies, picolinate concentrations have to be >10-4 M to lower the adsorption of Ni and Co. For Sm(III), Th(IV), Np(V), U(VI), and Pu, the picolinate concentration must be >10-3 M before adsorption decreases. EDTA forms strong complexes with divalent transition metals and can stop adsorption of Ni and Co when EDTA solution concentrations are 10-5 M. EDTA complexes with Np(V), U(VI), and Pu are much weaker; EDTA concentrations would have to be >10-3 M to adversely effects non-transition metal/radionuclide adsorption. Most picolinate and ETDA-metal complexes appear to readily dissociate during interactions with soils. The enhanced migration of radionuclide-organic complexes may be limited to a few unique conditions. We recommend that mixtures of metal/radionuclides and EDTA should not be solidified or co-disposed with high pH materials such as cement. For weaker binding organic complexants, such as picolinate, citrate and oxalate, co-disposal of decontamination wastes and concrete should be acceptable.

  17. The Development and Application of Reactive Transport Modeling Techniques to Study Radionuclide Migration at Yucca Mountain, NV

    SciTech Connect

    Viswanathan, Hari Selvi

    1999-09-01

    Yucca Mountain, Nevada has been chosen as a possible site for the first high level radioactive waste repository in the United States. As part of the site investigation studies, we need to make scientifically rigorous estimations of radionuclide migration in the event of a repository breach. Performance assessment models used to make these estimations are computationally intensive. We have developed two reactive transport modeling techniques to simulate radionuclide transport at Yucca Mountain: (1) the selective coupling approach applied to the convection-dispersion-reaction (CDR) model and (2) a reactive stream tube approach (RST). These models were designed to capture the important processes that influence radionuclide migration while being computationally efficient. The conventional method of modeling reactive transport models is to solve a coupled set of multi-dimensional partial differential equations for the relevant chemical components in the system. We have developed an iterative solution technique, denoted the selective coupling method, that represents a versatile alternative to traditional uncoupled iterative techniques and the filly coupled global implicit method. We show that selective coupling results in computational and memory savings relative to these approaches. We develop RST as an alternative to the CDR method for solving large two- or three-dimensional reactive transport simulations for cases in which one is interested in predicting the flux across a specific control plane. In the RST method, the multidimensional problem is reduced to a series of one-dimensional transport simulations along streamlines. The key assumption with RST is that mixing at the control plane approximates the transverse dispersion between streamlines. We compare the CDR and RST approaches for several scenarios that are relevant to the Yucca Mountain Project. For example, we apply the CDR and RST approaches to model an ongoing field experiment called the Unsaturated Zone

  18. Colloid and Colloid-Facilitated Contaminant Transport Experiments and Models to Support Assessments of Radionuclide Migration at Yucca Mountain and the Nevada Test Site

    SciTech Connect

    P. Reimus

    2004-06-01

    In recent years, numerous laboratory and field experiments have been conducted to assess and parameterize colloid and colloid-facilitated radionuclide transport for the Yucca Mountain Project and the Nevada Test Site (NTS) Environmental Restoration Project. Radionuclide contamination of ground water currently exists within or near underground nuclear test cavities at the NTS, and the proposed Yucca Mountain high-level nuclear waste repository represents a potential future source of radionuclide contamination of ground water at the NTS. Furthermore, recent field observations have indicated that small amounts of Plutonium, which normally adsorbs very strongly to mineral surfaces in aquifers, can transport quite rapidly and over significant distances in ground water when associated with inorganic colloids (Kersting et al., 1999). Groundwater samples from all over the Nevada Test Site have been analyzed for colloid concentrations and size distributions, and it is clear that there are significant mass loadings of colloids in the ground water at some locations. These colloids represent mobile surface area for potentially transporting strongly-adsorbed radionuclides. Field transport experiments have involved the use of fluorescent-dyed carboxylate-modified latex (CML) microspheres in the 250- to 650-nm diameter size range as surrogates for natural colloids in forced-gradient tracer tests. These experiments have indicated that effective colloid filtration coefficients appear to decrease as time and length scales increase. They suggest that a small fraction of colloids may be able to transport significant distances in groundwater systems. Laboratory experiments have been conducted to determine radionuclide sorption and desorption parameters onto inorganic colloids present in the groundwater systems and also to determine transport parameters for inorganic colloids in both fractured and porous media present at the Nevada Test Site. More recent laboratory experiments have

  19. Sediment and radionuclide transport in rivers. Phase 3. Field sampling program for Cattaraugus and Buttermilk Creeks, New York

    SciTech Connect

    Ecker, R.M.; Walters, W.H.; Onishi, Y.

    1982-08-01

    A field sampling program was conducted on Cattaraugus and Buttermilk Creeks, New York during April 1979 to investigate the transport of radionuclides in surface waters as part of a continuing program to provide data for application and verification of Pacific Northwest Laboratory's (PNL) sediment and radionuclide transport model, SERATRA. Bed sediment, suspended sediment and water samples were collected during unsteady flow conditions over a 45 mile reach of stream channel. Radiological analysis of these samples included gamma ray spectrometry analysis, and radiochemical separation and analysis of Sr-90, Pu-238, Pu-239, 240, Am-241 and Cm-244. Tritium analysis was also performed on water samples. Based on the evaluation of radionuclide levels in Cattaraugus and Buttermilk Creeks, the Nuclear Fuel Services facility at West Valley, New York, may be the source of Cs-137, Sr-90, Cs-134, Co-60, Pu-238, Pu-239, 240, Am-241, Cm-244 and tritium found in the bed sediment, suspended sediment and water of Buttermilk and Cattaraugus Creeks. This field sampling effort was the last of a three phase program to collect hydrologic and radiologic data at different flow conditions.

  20. Modelling radionuclide transport in fractured media with a dynamic update of Kd values

    SciTech Connect

    Trinchero, Paolo; Painter, Scott L.; Ebrahimi, Hedieh; Koskinen, Lasse; Molinero, Jorge; Selroos, Jan -Olof

    2015-10-13

    Radionuclide transport in fractured crystalline rocks is a process of interest in evaluating long term safety of potential disposal systems for radioactive wastes. Given their numerical efficiency and the absence of numerical dispersion, Lagrangian methods (e.g. particle tracking algorithms) are appealing approaches that are often used in safety assessment (SA) analyses. In these approaches, many complex geochemical retention processes are typically lumped into a single parameter: the distribution coefficient (Kd). Usually, the distribution coefficient is assumed to be constant over the time frame of interest. However, this assumption could be critical under long-term geochemical changes as it is demonstrated that the distribution coefficient depends on the background chemical conditions (e.g. pH, Eh, and major chemistry). In this study, we provide a computational framework that combines the efficiency of Lagrangian methods with a sound and explicit description of the geochemical changes of the site and their influence on the radionuclide retention properties.

  1. Will global warming affect soil-to-plant transfer of radionuclides?

    PubMed

    Dowdall, M; Standring, W; Shaw, G; Strand, P

    2008-11-01

    Recent assessments of global climate/environmental change are reaching a consensus that global climate change is occurring but there is significant uncertainty over the likely magnitude of this change and its impacts. There is little doubt that all aspects of the natural environment will be impacted to some degree. Soil-to-plant transfer of radionuclides has long been a significant topic in radioecology, both for the protection of humans and the environment from the effects of ionising radiation. Even after five decades of research considerable uncertainty exists as to the interplay of key environmental processes in controlling soil-plant transfer. As many of these processes are, to a lesser or greater extent, climate-dependent, it can be argued that climate/environmental change will impact soil-to-plant transfer of radionuclides and subsequent transfers in specific environments. This discussion attempts to highlight the possible role of climatic and climate-dependent variables in soil-to-plant transfer processes within the overall predictions of climate/environmental change. The work is speculative, and intended to stimulate debate on a theme that radioecology has either ignored or avoided in recent years.

  2. Kinetic modeling of microbially-driven redox chemistry of radionuclides in subsurface environments: Coupling transport, microbial metabolism and geochemistry

    SciTech Connect

    WANG,YIFENG; PAPENGUTH,HANS W.

    2000-05-04

    Microbial degradation of organic matter is a driving force in many subsurface geochemical systems, and therefore may have significant impacts on the fate of radionuclides released into subsurface environments. In this paper, the authors present a general reaction-transport model for microbial metabolism, redox chemistry, and radionuclide migration in subsurface systems. The model explicitly accounts for biomass accumulation and the coupling of radionuclide redox reactions with major biogeochemical processes. Based on the consideration that the biomass accumulation in subsurface environments is likely to achieve a quasi-steady state, they have accordingly modified the traditional microbial growth kinetic equation. They justified the use of the biogeochemical models without the explicit representation of biomass accumulation, if the interest of modeling is in the net impact of microbial reactions on geochemical processes. They then applied their model to a scenario in which an oxic water flow containing both uranium and completing organic ligands is recharged into an oxic aquifer in a carbonate formation. The model simulation shows that uranium can be reduced and therefore immobilized in the anoxic zone created by microbial degradation.

  3. Application of natural radionuclides for determination of tropospheric ozone and aerosol transport.

    SciTech Connect

    Gaffney, J. S.; Marley, N. A.; Drayton, P. J.; Orlandini, K. A.

    2000-12-06

    Natural radionuclides have been proposed for use in assessing the transport of ozone and aerosols in the troposphere. For example, {sup 7}Be is known to be produced in the upper troposphere and lower stratosphere by interactions with cosmogenic particles. Beryllium-7 has a 53.28-day half-life and is a gamma emitter that attaches itself to fine particles in the atmosphere once it is formed. Indeed, in tropospheric aerosol samples TBe is typically found in association with aerosol particles that are 0.3 {micro}m in diameter. Some investigators have asserted that ozone from aloft can be transported into rural and urban regions during stratospheric/tropospheric folding events, leading to increased background levels of ozone. During the Texas 2000 Air Quality study, aerosol samples with a 2.5-{micro}m cutoff were collected during 12-hour cycles (day/night) for a 30-day period at the Deer Park, Texas, field site in August-September 2000. To monitor {sup 7}Be levels, high-volume samples were collected on glass fiber filters on Julian dates 225-259. Sample collection was at a field site near a city park, away from any nearby traffic. This site is under routine operation by the Texas Natural Resource Conservation Commission. Instruments operated at this same site during the study period included an ozone monitor (Dasibi), a nitrogen oxides instrument (API), a CO instrument (API), a nephelometer, a UV-B meter (Richardson-Berger), and a multifilter rotating shadow band radiometer (MFRSR, Yankee Environmental Systems). In addition, we made modified fast-response NO{sub 2} and peroxyacetyl nitrate (PAN) measurements by using a fast gas chromatography with luminol detection, to be described at this meeting (3). The results for {sup 7}Be (mBq m{sup {minus}3})are compared in Figure 1 with the maximum and average ozone values (ppb) observed at the site to identify potential correlations. In Figure 2, all of the {sup 7}Be data are plotted against the maximum and average ozone

  4. Space Weather affects on Air Transportation

    NASA Astrophysics Data System (ADS)

    Jones, J. B. L.; Bentley, R. D.; Dyer, C.; Shaw, A.

    In Europe, legislation requires the airline industry to monitor the occupational exposure of aircrew to cosmic radiation. However, there are other significant impacts of space weather phenomena on the technological systems used for day-to-day operations which need to be considered by the airlines. These were highlighted by the disruption caused to the industry by the period of significant solar activity in late October and early November 2003. Next generation aircraft will utilize increasingly complex avionics as well as expanding the performance envelopes. These and future generation platforms will require the development of a new air-space management infrastructure with improved position accuracy (for route navigation and landing in bad weather) and reduced separation minima in order to cope with the expected growth in air travel. Similarly, greater reliance will be placed upon satellites for command, control, communication and information (C3I) of the operation. However, to maximize effectiveness of this globally interoperable C3I and ensure seamless fusion of all components for a safe operation will require a greater understanding of the space weather affects, their risks with increasing technology, and the inclusion of space weather information into the operation. This paper will review space weather effects on air transport and the increasing risks for future operations cause by them. We will examine how well the effects can be predicted, some of the tools that can be used and the practicalities of using such predictions in an operational scenario. Initial results from the SOARS ESA Space Weather Pilot Project will also be discussed,

  5. Distribution and transport kinetics of radionuclides sup 99 Mo and sup 131 I in a simulated aquatic ecosystem

    SciTech Connect

    Svadlenkova, M.; Konecny, J.; Obdrzalek, M.; Simanov, L. )

    1990-04-01

    Radioactive liquid wastes from nuclear power stations increase the activity not only of water but also of sediment, aquatic and shore plants, and animals. On average, the majority of the total radioactivity brought to the aquatic system is absorbed by the sediment; the remaining fraction is distributed between water and biomass. For us to be able to assess the influence of the nuclear power station at Temelin in South Bohemia on the nearby hydrosphere, the authors concentrated first on the experimental investigation of the distribution and transport kinetics of some radionuclides in a simulated aquatic system.

  6. LONG-TERM COLLOID MOBILIZATION AND COLLOID-FACILITATED TRANSPORT OF RADIONUCLIDES IN A SEMI-ARID VADOSE ZONE

    SciTech Connect

    Markus Flury; James B. Harsh; Fred Zhang; Glendon W. Gee; Earl D. Mattson; Peter C. L

    2012-08-01

    The main purpose of this project was to improve the fundamental mechanistic understanding and quantification of long-term colloid mobilization and colloid-facilitated transport of radionuclides in the vadose zone, with special emphasis on the semi-arid Hanford site. While we focused some of the experiments on hydrogeological and geochemical conditions of the Hanford site, many of our results apply to colloid and colloid-facilitated transport in general. Specific objectives were (1) to determine the mechanisms of colloid mobilization and colloid-facilitated radionuclide transport in undisturbed Hanford sediments under unsaturated flow, (2) to quantify in situ colloid mobilization and colloid-facilitated radionuclidetransport from Hanford sediments under field conditions, and (3) to develop a field-scale conceptual and numerical model for colloid mobilization and transport at the Hanford vadose zone, and use that model to predict long-term colloid and colloid- facilitated radionuclide transport. To achieve these goals and objectives, we have used a combination of experimental, theoretical, and numerical methods at different spatial scales, ranging from microscopic investigationsof single particle attachment and detachment to larger-scale field experiments using outdoor lysimeters at the Hanford site. Microscopic and single particle investigations provided fundamental insight into mechanisms of colloid interactions with the air-water interface. We could show that a moving air water interface (such as a moving water front during infiltration and drainage) is very effective in removing and mobilizing particles from a stationary surface. We further demonstrated that it is particularly the advancing air-water interface which is mainly responsible for colloid mobilization. Forces acting on the colloids calculated from theory corroborated our experimental results, and confirm that the detachment forces (surface tension forces) during the advancing air-water interface

  7. Radiation Effects on the Sorption and Mobilization of Radionuclide during Transport through the Geosphere

    SciTech Connect

    L.M. Wang; R.C. Eqing; K.F. Hayes

    2004-03-14

    Site restoration activities at DOE facilities and the permanent disposal of nuclear waste inevitably involve understanding the behavior of materials in a radiation field. Radionuclide decay and the associated radiation fields lead to physical and chemical changes that can degrade or enhance important material properties. Alpha-decay of the actinide elements and beta-decay of the fission products lead to atomic-scale changes in materials (radiation damage and transmutation).

  8. Modelling the global atmospheric transport and deposition of radionuclides from the Fukushima Dai-ichi nuclear accident.

    NASA Astrophysics Data System (ADS)

    Christoudias, Theodoros; Lelieveld, Jos

    2013-04-01

    We modeled the global atmospheric dispersion and deposition of radionuclides released from the Fukushima Dai-ichi nuclear power plant accident. The EMAC atmospheric chemistry - general circulation model was used, with circulation dynamics nudged towards ERA-Interim reanalysis data. We applied a resolution of approximately 0.5 degrees in latitude and longitude (T255). The model accounts for emissions and transport of the radioactive isotopes 131I and 137Cs, and removal processes through precipitation, particle sedimentation and dry deposition. In addition, we simulated the release of 133Xe, a noble gas that can be regarded as a passive transport tracer of contaminated air. The source terms are based on Chino et al. (2011) and Stohl et al. (2012); especially the emission estimates of 131I are associated with a high degree of uncertainty. The calculated concentrations have been compared to station observations by the Comprehensive Nuclear-Test-Ban Treaty Organisation (CTBTO).

  9. Radionuclide Therapy

    NASA Astrophysics Data System (ADS)

    Zalutsky, M. R.

    Radionuclide therapy utilizes unsealed sources of radionuclides as a treatment for cancer or other pathological conditions such as rheumatoid arthritis. Radionuclides that decay by the emission of β and α particles, as well as those that emit Auger electrons, have been used for this purpose. In this chapter, radiochemical aspects of radionuclide therapy, including criteria for radionuclide selection, radionuclide production, radiolabeling chemistry, and radiation dosimetry are discussed.

  10. Transuranic radionuclides from resuspension in the environment, a bibliography

    SciTech Connect

    Stoker, A.C.; Shinn, J.H.; Noshkin, V.E.

    1994-04-01

    The purpose of this project was to compile a bibliography of references containing environmental transuranic radionuclide data. Our intent was to identify those parameters affecting transuranic radionuclide transport that may be generic and those that may be dependent on chemical form and/or environmental conditions. An understanding of the unique characteristics and similarities between source terms and environmental conditions relative to transuranic radionuclide transport and cycling will provide the ability to assess and predict the long term impact on man and the environment. An additional goal of our literature review, was to extract the ranges of environmental transuranic radionuclide data from the identified references for inclusion in a data base. Related to source term, these ranges of data can be used to calculate the dose to man from the radionuclides, and to perform uncertainty analyses on these dose assessments. On the basis of our reviews, we have arbitrarily outlined five general source terms. These are fallout, fuel cycle waste, accidents, disposal sites and resuspension. Resuspension of the transuranic radionuclides is an unique source term, in that the radionuclides can originate from any of the other source terms. If these transuranic radionuclides become resuspended into the air, they then become important as a source of inhaled radionuclides. This bibliography is a compilation of the references containing studies of plutonium and americium in the environment as a result of resuspension.

  11. Transuranic radionuclides dispersed into the aquatic environment, a bibliography

    SciTech Connect

    Noshkin, V.E.; Stoker, A.C.; Wong, Kai M.

    1994-04-01

    The purpose of this project was to compile a bibliography of references containing environmental transuranic radionuclide data. Our intent was to identify those parameters affecting transuranic radionuclide transport that may be generic and those that may be dependent on chemical form and/or environmental conditions (i.e., site specific) in terrestrial, aquatic and atmospheric environments An understanding of the unique characteristics and similarities between source terms and environmental conditions relative to transuranic radionuclide transport and cycling will provide the ability to assess and predict the long term impact on man and the environment. An additional goal of our literature review, was to extract the ranges of environmental transuranic radionuclide data from the identified references for inclusion in a data base. Related to source term, these ranges of data can be used to calculate the dose to man from the radionuclides, and to perform uncertainty analyses on these dose assessments. On the basis of our reviews, we have arbitrarily outlined five general source terms. These are fallout, fuel cycle waste, accidents, disposal sites and resuspension. Resuspension of the transuranic radionuclides is a unique source term, in that the radionuclides can originate from any of the other source terms. If these transuranic radionuclides become resuspended into the air, they then become important as a source of inhaled radionuclides.

  12. Behaviour and transport of radionuclides in soil and vegetation of a sand dune ecosystem.

    PubMed

    Copplestone, D; Johnson, M S; Jones, S R

    2001-01-01

    A sand dune ecosystem in the vicinity of the British Nuclear Fuels reprocessing plant at Sellafield, Cumbria, UK was used to examine the spatial, temporal and depth distributions of 134Cs, 137Cs, 238Pu, 239 + 240Pu and 241Am in soil and in two species of vegetation (Festuca rubra, Ammophila arenaria). Core samples showed evidence of the accumulation of radionuclides derived mainly from sea-to-land transfer. Accumulated deposits of radioactivity (0-0.1 m) lie within the range: 1.1-3.4 Bq kg-1 (134Cs), 260-440 Bq kg-1 (137Cs), 31-40 Bq kg-1 (238Pu), 150-215 Bq kg-1 (239 + 240Pu) and 190-240 Bq kg-1 (241Am). Soil profiles showed greater activity concentrations in their deeper regions and this is attributed to leaching of radionuclides in percolating drainage water accentuated by the coarse texture, low organic matter and clay mineral content of coastal sands. Radionuclide activity concentrations in F. rubra and A. arenaria were similar, in the ranges 20-70 Bq kg-1 (137Cs), 1-5 Bq kg-1 (238Pu), 10-30 Bq kg-1 (239 + 240Pu) and 10-65 Bq kg-1 (241Am). Clear temporal and spatial variations were observed in both species of vegetation, reflecting the weather conditions antecedent to the sampling period and the influence of sea-to-land transfer. Concentration ratios (vegetation:soil) for activity concentrations in the two species were similar, in the ranges: 0.05-0.14 (137Cs), 0.025-0.097 (238Pu), 0.022-0.057 (239 + 240Pu) and 0.025-0.212 (241Am).

  13. A regional sediment transport modeling for assessing dispersal and recirculation of land-derived radionuclides in the Fukushima coast

    NASA Astrophysics Data System (ADS)

    Yamanishi, T.; Uchiyama, Y.; Tsumune, D.; Miyazawa, Y.

    2014-12-01

    Fluvial discharge from the rivers is viewed as a missing piece in the inventory of the radionuclides in the ocean during the accident at the Fukushima Daiichi Nuclear Power Plant (FNPP). The land-derived input introduces a time lag behind the direct release through hydrological process because these radionuclides mostly attach to suspended fine particles (sediments) that are transported quite differently to the dissolved matter. Therefore, we implement a sediment transport model proposed by Blaas et al. (2007) consisting of a multi-class non-cohesive sediment transport model, a wave-enhanced bed boundary layer model, and a stratigraphy model into ROMS. A 128 x 256 km domain with the grid resolution of dx = 250 m centered at FNPP is configured as a test bed embedded in the existing ROMS model domain at dx = 1 km (Uchiyama et al., 2012, 2013). A spectral wave model SWAN at dx = 1 km nested in the JMA GPV-CWM wave reanalysis is used for the wave forcing field. A surface runoff model (Toyota et al., 2009) provides daily-mean discharges and associated sediment fluxes at the mouths of 20 rivers in the study area.The model results show that bed stresses are enhanced in the coastal area about 10 to 20 km from the shore, most part of the semi-sheltered Sendai Bay, and on the continental shelf slope at about 600 m deep. In contrast, band-like structures are formed between the nearshore and the shelf slope where bed stresses are found to be modest. This low stress bands correspond to the areas where fine particles such as silt and clay are predominant in the bed. Since the cesium 137 is quite readily attached to fine particles rather than coarse sediments (sand), this result suggests that the band acts as a hot spot of the sediment-attached radionuclides. Indeed, a qualitative correlation is found between the low stress band with high radioactivity of cesium 137 in the bed sediment off FNPP based on the field measurement (Ambe et al., 2013).

  14. Atmospheric Transport Modelling assessing radionuclide detection chances after the nuclear test announced by the DPRK in January 2016

    NASA Astrophysics Data System (ADS)

    Ross, J. Ole; Ceranna, Lars

    2016-04-01

    The Comprehensive Nuclear-Test-Ban Treaty (CTBT) prohibits all kinds of nuclear explosions. The International Monitoring System (IMS) is in place and at about 90% complete to verify compliance with the CTBT. The stations of the waveform technologies are capable to detect seismic, hydro-acoustic and infrasonic signals for detection, localization, and characterization of explosions. The seismic signals of the DPRK event on 6 January 2016 were detected by many seismic stations around the globe and allow for localization of the event and identification as explosion (see poster by G. Hartmann et al.). However, the direct evidence for a nuclear explosion is only possible through the detection of nuclear fission products which may be released. For that 80 Radionuclide (RN) Stations are part of the designed IMS, about 60 are already operational. All RN stations are highly sensitive for tiny traces of particulate radionuclides in large volume air samplers. There are 40 of the RN stations designated to be equipped with noble gas systems detecting traces of radioactive xenon isotopes which are more likely to escape from an underground test cavity than particulates. Already 30 of the noble gas systems are operational. Atmospheric Transport Modelling supports the interpretation of radionuclide detections (and as appropriate non-detections) by connecting the activity concentration measurements with potential source locations and release times. In our study forecasts with the Lagrangian Particle Dispersion Model HYSPLIT (NOAA) and GFS (NCEP) meteorological data are considered to assess the plume propagation patterns for hypothetical releases at the known DPRK nuclear test site. The results show a considerable sensitivity of the IMS station RN 38 Takasaki (Japan) to a potential radionuclide release at the test site in the days and weeks following the explosion in January 2016. In addition, backtracking simulations with ECMWF analysis data in 0.2° horizontal resolution are

  15. Action levels for automatic gamma-measurements based on probabilistic radionuclide transport calculations.

    PubMed

    Lauritzen, Bent; Hedemann-Jensen, Per

    2005-12-01

    In the event of a nuclear or radiological emergency resulting in an atmospheric release of radioactive materials, stationary gamma-measurements, for example obtained from distributed, automatic monitoring stations, may provide a first assessment of exposures resulting from airborne and deposited activity. Decisions on the introduction of countermeasures for the protection of the public can be based on such off-site gamma measurements. A methodology is presented for calculation of gamma-radiation action levels for the introduction of specific countermeasures, based on probabilistic modelling of the dispersion of radionuclides and the radiation exposure. The methodology is applied to a nuclear accident situation with long-range atmospheric dispersion of radionuclides, and action levels of dose rate measured by a network of monitoring stations are estimated for sheltering and foodstuff restrictions. It is concluded that the methodology is applicable to all emergency countermeasures following a nuclear accident but measurable quantities other than ambient dose equivalent rate are needed for decisions on the introduction of foodstuff countermeasures.

  16. URANIUM-SERIES CONSTRAINTS ON RADIONUCLIDE TRANSPORT AND GROUNDWATER FLOW AT NOPAL I URANIUM DEPOSIT, SIERRA PENA BLANCA, MEXICO

    SciTech Connect

    S. J. Goldstein, S. Luo, T. L. Ku, and M. T. Murrell

    2006-04-01

    Uranium-series data for groundwater samples from the vicinity of the Nopal I uranium ore deposit are used to place constraints on radionuclide transport and hydrologic processes at this site, and also, by analogy, at Yucca Mountain. Decreasing uranium concentrations for wells drilled in 2003 suggest that groundwater flow rates are low (< 10 m/yr). Field tests, well productivity, and uranium isotopic constraints also suggest that groundwater flow and mixing is limited at this site. The uranium isotopic systematics for water collected in the mine adit are consistent with longer rock-water interaction times and higher uranium dissolution rates at the front of the adit where the deposit is located. Short-lived nuclide data for groundwater wells are used to calculate retardation factors that are on the order of 1,000 for radium and 10,000 to 10,000,000 for lead and polonium. Radium has enhanced mobility in adit water and fractures near the deposit.

  17. Coupling of Nuclear Waste Form Corrosion and Radionuclide Transports in Presence of Relevant Repository Sediments

    SciTech Connect

    Wall, Nathalie A.; Neeway, James J.; Qafoku, Nikolla P.; Ryan, Joseph V.

    2015-09-30

    Assessments of waste form and disposal options start with the degradation of the waste forms and consequent mobilization of radionuclides. Long-term static tests, single-pass flow-through tests, and the pressurized unsaturated flow test are often employed to study the durability of potential waste forms and to help create models that predict their durability throughout the lifespan of the disposal site. These tests involve the corrosion of the material in the presence of various leachants, with different experimental designs yielding desired information about the behavior of the material. Though these tests have proved instrumental in elucidating various mechanisms responsible for material corrosion, the chemical environment to which the material is subject is often not representative of a potential radioactive waste repository where factors such as pH and leachant composition will be controlled by the near-field environment. Near-field materials include, but are not limited to, the original engineered barriers, their resulting corrosion products, backfill materials, and the natural host rock. For an accurate performance assessment of a nuclear waste repository, realistic waste corrosion experimental data ought to be modeled to allow for a better understanding of waste form corrosion mechanisms and the effect of immediate geochemical environment on these mechanisms. Additionally, the migration of radionuclides in the resulting chemical environment during and after waste form corrosion must be quantified and mechanisms responsible for migrations understood. The goal of this research was to understand the mechanisms responsible for waste form corrosion in the presence of relevant repository sediments to allow for accurate radionuclide migration quantifications. The rationale for this work is that a better understanding of waste form corrosion in relevant systems will enable increased reliance on waste form performance in repository environments and potentially

  18. BiP negatively affects ricin transport.

    PubMed

    Gregers, Tone F; Skånland, Sigrid S; Wälchli, Sébastien; Bakke, Oddmund; Sandvig, Kirsten

    2013-05-10

    The AB plant toxin ricin binds both glycoproteins and glycolipids at the cell surface via its B subunit. After binding, ricin is endocytosed and then transported retrogradely through the Golgi to the endoplasmic reticulum (ER). In the ER, the A subunit is retrotranslocated to the cytosol in a chaperone-dependent process, which is not fully explored. Recently two separate siRNA screens have demonstrated that ER chaperones have implications for ricin toxicity. ER associated degradation (ERAD) involves translocation of misfolded proteins from ER to cytosol and it is conceivable that protein toxins exploit this pathway. The ER chaperone BiP is an important ER regulator and has been implicated in toxicity mediated by cholera and Shiga toxin. In this study, we have investigated the role of BiP in ricin translocation to the cytosol. We first show that overexpression of BiP inhibited ricin translocation and protected cells against the toxin. Furthermore, shRNA-mediated depletion of BiP enhanced toxin translocation resulting in increased cytotoxicity. BiP-dependent inhibition of ricin toxicity was independent of ER stress. Our findings suggest that in contrast to what was shown with the Shiga toxin, the presence of BiP does not facilitate, but rather inhibits the entry of ricin into the cytosol.

  19. Scale-Dependent Fracture-Matrix Interactions and Their Impact on Radionuclide Transport: Development of efficient particle-tracking methods

    SciTech Connect

    Rajaram, Harihar; Brutz, Michael; Klein, Dylan R; Mallikamas, Wasin

    2014-09-18

    Matrix Diffusion and Adsorption within a rock matrix are important mechanisms for retarding transport of radionuclides in fractured rock. Due to computational limitations and difficulties in characterizing complex subsurface systems, diffusive exchange between a fracture network and surrounding rock matrix is often modeled using simplified conceptual representations. There is significant uncertainty in “effective” parameters used in these models, such as the “effective matrix diffusivity”. Often, these parameters are estimated by fitting sparse breakthrough data, and estimated values fall outside meaningful ranges, because simplified interpretive models do not consider complex three-dimensional flow. There is limited understanding of the relationship between the effective parameters and rock mass characteristics including network structure and matrix properties. There is also evidence for an apparent scale-dependence in “effective matrix diffusion” coefficients. These observations raise questions on whether fracture-matrix interaction parameters estimated from small-scale tracer tests can be used for predicting radionuclide fate and transport at the scale of DOE field sites. High-resolution three-dimensional Discrete-Fracture-Network-Matrix (DFNM) models based on well-defined local scale transport equations can help to address some of these questions. Due to tremendous advances in computational technology over the last 10 years, DFNM modeling in relatively large domains is now feasible. The overarching objective of our research is to use DFNM modeling to improve fundamental understanding of how effective parameters in conceptual models are related to fracture network structure and matrix properties. An advanced three-dimensional DFNM model is being developed, which combines upscaled particle-tracking algorithms for fracture-matrix interaction and a parallel fracture-network flow simulator. The particle-tracking algorithms allow complexity in flow fields

  20. Transport of radionuclides from the Mururoa and Fangataufa atolls through the marine environment.

    PubMed

    Mittelstaedt, E; Osvath, I; Povinec, P P; Togawa, O; Scott, E M

    1999-09-30

    A dispersion of radionuclides (3H, 90Sr, 137Cs, 239Pu) potentially released from the Mururoa and Fangataufa atolls through the South Pacific Ocean has been studied by means of computer models. The models used consisted of three differently structured compartmental models for the regional field and a hydrodynamic world ocean model for the far-field simulations. The outcome of regional modelling is predicted activity concentrations with time in different regions of French Polynesia (over up to 10,000 years for plutonium). The far-field model simulates large-scale dispersion in the South Pacific Ocean over periods of up to 50 years. The overall result suggests that there will not be radioactive contamination of any radiological interest at inhabited sites in French Polynesia or anywhere else in the ocean at present or in the future.

  1. Assessment of potential radionuclide transport in site-specific geologic formations

    SciTech Connect

    Dosch, R.G.

    1980-08-01

    Associated with the development of deep, geologic repositories for nuclear waste isolation is a need for safety assessments of the potential for nuclide migration. Frequently used in estimating migration rates is a parameter generally known as a distribution coefficient, K/sub d/, which describes the distribution of a radionuclide between a solid (rock) and a liquid (groundwater) phase. This report is intended to emphasize that the use of K/sub d/ must be coupled with a knowledge of the geology and release scenarios applicable to a repository. Selected K/sub d/ values involving rock samples from groundwater/brine simulants typical of two potential repository sites, WIPP and NTS, are used to illustrate this concern. Experimental parameters used in K/sub d/ measurements including nuclide concentration, site sampling/rock composition, and liquid-to-solid ratios are discussed. The solubility of U(VI) in WIPP brine/groundwater was addressed in order to assess the potential contribution of this phenomena to K/sub d/ values. Understanding mehanisms of sorption of radionuclides on rocks would lead to a better predictive capability. Sorption is attributed to the presence of trace constituents (often unidentified) in rocks. An attempt was made to determine if this applied to WIPP dolomite rocks by comparing sorption behavior of the natural material with that of a synthetic dolomite prepared in the laboratory with reagent grade chemicals. The results were inconclusive. The results of a study of Tc sorption by an argillite sample from the Calico Hills formation at NTS under ambient laboratory conditions were more conclusive. The Tc sorption was found to be associated with elemental carbon. Available evidence points to a reduction mechanism leading to the apparent sorption of Tc on the solid phase.

  2. Modeling of Groundwater Flow and Radionuclide Transport at the Climax Mine sub-CAU, Nevada Test Site

    SciTech Connect

    K. Pohlmann; M. Ye; D. Reeves; M. Zavarin; D. Decker; J. Chapman

    2007-09-28

    The Yucca Flat-Climax Mine Corrective Action Unit (CAU) on the Nevada Test Site comprises 747 underground nuclear detonations, all but three of which were conducted in alluvial, volcanic, and carbonate rocks in Yucca Flat. The remaining three tests were conducted in the very different hydrogeologic setting of the Climax Mine granite stock located in Area 15 at the northern end of Yucca Flat. As part of the Corrective Action Investigation (CAI) for the Yucca Flat-Climax Mine CAU, models of groundwater flow and radionuclide transport will be developed for Yucca Flat. However, two aspects of these CAU-scale models require focused modeling at the northern end of Yucca Flat beyond the capability of these large models. First, boundary conditions and boundary flows along the northern reaches of the Yucca Flat-Climax Mine CAU require evaluation to a higher level of detail than the CAU-scale Yucca Flat model can efficiently provide. Second, radionuclide fluxes from the Climax tests require analysis of flow and transport in fractured granite, a unique hydrologic environment as compared to Yucca Flat proper. This report describes the Climax Mine sub-CAU modeling studies conducted to address these issues, with the results providing a direct feed into the CAI for the Yucca Flat-Climax Mine CAU. Three underground nuclear detonations were conducted for weapons effects testing in the Climax stock between 1962 and 1966: Hard Hat, Pile Driver, and Tiny Tot. Though there is uncertainty regarding the position of the water table in the stock, it is likely that all three tests were conducted in the unsaturated zone. In the early 1980s, the Spent Fuel Test-Climax (SFT-C) was constructed to evaluate the feasibility of retrievable, deep geologic storage of commercial nuclear reactor wastes. Detailed mapping of fractures and faults carried out for the SFT-C studies greatly expanded earlier data sets collected in association with the nuclear tests and provided invaluable information for

  3. Distribution patterns of particle-reactive radionuclides in sediments off eastern Hainan Island, China: Implications for source and transport pathways

    NASA Astrophysics Data System (ADS)

    Huang, Dekun; Du, Jinzhou; Deng, Bing; Zhang, Jing

    2013-04-01

    The study of sediment sources and transport processes from land to ocean can help in predicting the fate of the pollutants released from land or the potential change in sediment delivery to coastal areas and/or open oceans. The activities of 7Be, excess 210Pb (210Pbxs), excess 234Th (234Thxs) and 137Cs in surface sediments collected offshore of eastern Hainan Island, China, in August of 2008 were measured by an HPGe γ-spectrometer to evaluate the sediment source and transport processes. The results showed that all the surface sediments were silt or sand, and the mean grain sizes of the northern locations were higher than those in the other regions. The ranges of activities of 7Be, 210Pbxs, 234Thxs and 137Cs in surface sediment were 0.14-12.7, 37.4-199, 2.24-176 and 0.02-1.06 Bq kg-1, with averages of 3.78±4.77, 110±8.1, 66.7±8.9 and 0.52±0.22 Bq kg-1, respectively. The activities of the radionuclides increased from coast to offshore in the northern section. The upwelling may cause high particle fluxes with high activities of 210Pbxs and 234Thxs. A comparison of the source and transport of the suspended sediments with river discharge along the coast shows that the coastal current and offshore upwelling are the dominant factors for the transport and sources of surface sediment in the study region. The sediment was transported from south to north by the coastal current, and sediments with a large grain size may be deposited via the north loop current. The ratios of the nuclide activities indicated that the suspended particles need approximately one year to be removed from the water column into the seabed and that the main source of the sediments off eastern Hainan Island in the study regions was terrigenous deposits.

  4. CASCADER: An m-chain gas-phase radionuclide transport and fate model. Volume 2, User`s manual for CASCADR8

    SciTech Connect

    Cawlfield, D.E.; Been, K.B.; Emer, D.F.; Lindstrom, F.T.; Shott, G.J.

    1993-06-01

    Chemicals and radionuclides move either in the gas-phase, liquid-phase, or both phases in soils. They may be acted upon by either biological or abiotic processes through advection and/or diffusion. Furthermore, parent and daughter radionuclides may decay as they are transported in the soil. This is volume two to the CASCADER series, titled CASCADR8. It embodies the concepts presented in volume one of this series. To properly understand how the CASCADR8 model works, the reader should read volume one first. This volume presents the input and output file structure for CASCADR8, and a set of realistic scenarios for buried sources of radon gas.

  5. Identification of sorption processes and parameters for radionuclide transport in fractured rock

    NASA Astrophysics Data System (ADS)

    Dai, Zhenxue; Wolfsberg, Andrew; Reimus, Paul; Deng, Hailin; Kwicklis, Edward; Ding, Mei; Ware, Doug; Ye, Ming

    2012-01-01

    SummaryIdentification of chemical reaction processes in subsurface environments is a key issue for reactive transport modeling because simulating different processes requires developing different chemical-mathematical models. In this paper, two sorption processes (equilibrium and kinetics) are considered for modeling neptunium and uranium sorption in fractured rock. Based on different conceptualizations of the two processes occurring in fracture and/or matrix media, seven dual-porosity, multi-component reactive transport models are developed. The process models are identified with a stepwise strategy by using multi-tracer concentration data obtained from a series of transport experiments. In the first step, breakthrough data of a conservative tracer (tritium) obtained from four experiments are used to estimate the flow and non-reactive transport parameters (i.e., mean fluid residence time in fracture, fracture aperture, and matrix tortuosity) common to all the reactive transport models. In the second and third steps, by fixing the common non-reactive flow and transport parameters, the sorption parameters (retardation factor, sorption coefficient, and kinetic rate constant) of each model are estimated using the breakthrough data of reactive tracers, neptunium and uranium, respectively. Based on the inverse modeling results, the seven sorption-process models are discriminated using four model discrimination (or selection) criteria, Akaike information criterion ( AIC), modified Akaike information criterion ( AICc), Bayesian information criterion ( BIC) and Kashyap information criterion ( KIC). These criteria suggest the kinetic sorption process for modeling reactive transport of neptunium and uranium transport in both fracture and matrix. This conclusion is confirmed by two chemical criteria, the half reaction time and Damköhler number criterion.

  6. Modelling the global atmospheric transport and deposition of radionuclides from the Fukushima Dai-ichi nuclear accident

    NASA Astrophysics Data System (ADS)

    Christoudias, T.; Lelieveld, J.

    2013-02-01

    We modeled the global atmospheric dispersion and deposition of radionuclides released from the Fukushima Dai-ichi nuclear power plant accident. The EMAC atmospheric chemistry - general circulation model was used, with circulation dynamics nudged towards ERA-Interim reanalysis data. We applied a resolution of approximately 0.5 degrees in latitude and longitude (T255). The model accounts for emissions and transport of the radioactive isotopes 131I and 137Cs, and removal processes through precipitation, particle sedimentation and dry deposition. In addition, we simulated the release of 133Xe, a noble gas that can be regarded as a passive transport tracer of contaminated air. The source terms are based on Chino et al. (2011) and Stohl et al. (2012); especially the emission estimates of 131I are associated with a high degree of uncertainty. The calculated concentrations have been compared to station observations by the Comprehensive Nuclear-Test-Ban Treaty Organisation (CTBTO). We calculated that about 80% of the radioactivity from Fukushima which was released to the atmosphere deposited into the Pacific Ocean. In Japan a large inhabited land area was contaminated by more than 40 kBq m-2. We also estimated the inhalation and 50-year dose by 137Cs, 134Cs and 131I to which the people in Japan are exposed.

  7. Modelling the global atmospheric transport and deposition of radionuclides from the Fukushima Dai-ichi nuclear accident

    NASA Astrophysics Data System (ADS)

    Christoudias, T.; Lelieveld, J.

    2012-09-01

    We modeled the global atmospheric dispersion and deposition of radionuclides released from the Fukushima Dai-ichi nuclear power plant accident. The EMAC atmospheric chemistry - general circulation model was used, with circulation dynamics nudged towards ERA-Interim reanalysis data. We applied a resolution of approximately 0.5 degrees in latitude and longitude (T255). The model accounts for emissions and transport of the radioactive isotopes 131I and 137Cs, and removal processes through precipitation, particle sedimentation and dry deposition. In addition, we simulated the release of 133Xe, a noble gas that can be regarded as a passive transport tracer of contaminated air. The source terms are based on Stohl et al. (2012) and Chino et al. (2011); especially the emission estimates of 131I are associated with a high degree of uncertainty. The calculated concentrations have been compared to station observations by the Comprehensive Nuclear-Test-Ban Treaty Organisation (CTBTO). We calculated that about 80% of the radioactivity from Fukushima which was released to the atmosphere deposited into the Pacific Ocean. In Japan a land area of 34 000 km2 around the reactors, inhabited by nearly 10 million people, was contaminated by more than 40 kBq m-2. We also estimated the inhalation and 50-yr dose by 137Cs and 131I to which the people in Japan have been exposed.

  8. Radionuclide source scenario and forward atmospheric transport modeling for the National Data Center Preparedness Exercise 2012

    NASA Astrophysics Data System (ADS)

    Ross, Ole; Schlosser, Clemens; Gestermann, Nicolai; Ceranna, Lars; Bönnemann, Christian

    2013-04-01

    For verification with compliance of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) the International Monitoring System (IMS) operates stations observing seismic, hydroacoustic, and infrasound signals as well as radioisotopes in the atmosphere. While the IMS data is collected, processed and technically analyzed in the International Data Center (IDC) of the CTBT-Organization, National Data Centers (NDC) provide interpretation and advice to their government concerning suspicious detections occurring in IMS data. NDC Preparedness Exercises (NPE) are regularly performed dealing with fictitious treaty violations to practice the combined analysis of CTBT verification technologies and mutual exchange of information between NDCs and with the IDC as well. For NPE 2012 the trigger scenario was based on a selected seismic event from the Reviewed Event Bulletin serving as starting point for fictitious radionuclide dispersion. Hypothetical xenon and iodine radioisotope source terms with isotopic ratios fitting to a nuclear explosion were assumed. The simulated concentrations at dedicated IMS stations were calculated using the NOAA HYSPLIT model driven by NCEP GDAS analysis data with 0.5 degree horizontal resolution. Noble gas and particulate emissions were treated separately considering wet and dry deposition for the iodine. Only stations which were operational and sending data at that time were taken for the creation of virtual samples according to the actual collection times. The actual meteorological conditions during the days following the NPE 2012 event and the location of the IMS stations lead to a detection pattern which allowed for sufficient backtracking results using the data and software provided by IDC. For participants without ATM capacity two additional entrance levels were offered upon request: Either a space-time-box containing the trigger event or even the complete REB entry containing source and waveform parameters.

  9. Modeling Groundwater Flow and Transport of Radionuclides at Amchitka Island's Underground Nuclear Tests: Milrow, Long Shot, and Cannikin

    SciTech Connect

    Ahmed Hassan; Karl Pohlmann; Jenny Chapman

    2002-11-19

    Since 1963, all United States nuclear tests have been conducted underground. A consequence of this testing has been the deposition of large amounts of radioactive material in the subsurface, sometimes in direct contact with groundwater. The majority of this testing occurred on the Nevada Test Site (NTS), but a limited number of experiments were conducted in other locations. One of these locations, Amchitka Island, Alaska is the subject of this report. Three underground nuclear tests were conducted on Amchitka Island. Long Shot was an 80-kiloton-yield test conducted at a depth of 700 meters (m) on October 29, 1965 (DOE, 2000). Milrow had an announced yield of about 1,000 kilotons, and was detonated at a depth of 1,220 m on October 2, 1969. Cannikin had an announced yield less than 5,000 kilotons, and was conducted at a depth of 1,790 m on November 6, 1971. The purpose of this work is to provide a portion of the information needed to conduct a human-health risk assessment of the potential hazard posed by the three underground nuclear tests on Amchitka Island. Specifically, the focus of this work is the subsurface transport portion, including the release of radionuclides from the underground cavities and their movement through the groundwater system to the point where they seep out of the ocean floor and into the marine environment. This requires a conceptual model of groundwater flow on the island using geologic, hydrologic, and chemical information, a numerical model for groundwater flow, a conceptual model of contaminant release and transport properties from the nuclear test cavities, and a numerical model for contaminant transport. Needed for the risk assessment are estimates of the quantity of radionuclides (in terms of mass flux) from the underground tests on Amchitka that could discharge to the ocean, the time of possible discharge, and the location in terms of distance from shoreline. The radionuclide data presented here are all reported in terms of normalized

  10. Mathematical modeling and evaluation of radionuclide transport parameters from the ANL Laboratory Analog Program

    SciTech Connect

    Chen, B.C.J.; Hull, J.R.; Seitz, M.G.; Sha, W.T.; Shah, V.L.; Soo, S.L.

    1984-07-01

    Computer model simulation is required to evaluate the performance of proposed or future high-level radioactive waste geological repositories. However, the accuracy of a model in predicting the real situation depends on how well the values of the transport properties are prescribed as input parameters. Knowledge of transport parameters is therefore essential. We have modeled ANL's Experiment Analog Program which was designed to simulate long-term radwaste migration process by groundwater flowing through a high-level radioactive waste repository. Using this model and experimental measurements, we have evaluated neptunium (actinide) deposition velocity and analyzed the complex phenomena of simultaneous deposition, erosion, and reentrainment of bentonite when groundwater is flowing through a narrow crack in a basalt rock. The present modeling demonstrates that we can obtain the values of transport parameters, as added information without any additional cost, from the available measurements of laboratory analog experiments. 8 figures, 3 tables.

  11. Radionuclide trap

    DOEpatents

    McGuire, Joseph C.

    1978-01-01

    The deposition of radionuclides manganese-54, cobalt-58 and cobalt-60 from liquid sodium coolant is controlled by providing surfaces of nickel or high nickel alloys to extract the radionuclides from the liquid sodium, and by providing surfaces of tungsten, molybdenum or tantalum to prevent or retard radionuclide deposition.

  12. Uranium-series constraints on radionuclide transport and groundwater flow at the Nopal I uranium deposit, Sierra Pena Blanca, Mexico.

    PubMed

    Goldstein, Steven J; Abdel-Fattah, Amr I; Murrell, Michael T; Dobson, Patrick F; Norman, Deborah E; Amato, Ronald S; Nunn, Andrew J

    2010-03-01

    Uranium-series data for groundwater samples from the Nopal I uranium ore deposit were obtained to place constraints on radionuclide transport and hydrologic processes for a nuclear waste repository located in fractured, unsaturated volcanic tuff. Decreasing uranium concentrations for wells drilled in 2003 are consistent with a simple physical mixing model that indicates that groundwater velocities are low ( approximately 10 m/y). Uranium isotopic constraints, well productivities, and radon systematics also suggest limited groundwater mixing and slow flow in the saturated zone. Uranium isotopic systematics for seepage water collected in the mine adit show a spatial dependence which is consistent with longer water-rock interaction times and higher uranium dissolution inputs at the front adit where the deposit is located. Uranium-series disequilibria measurements for mostly unsaturated zone samples indicate that (230)Th/(238)U activity ratios range from 0.005 to 0.48 and (226)Ra/(238)U activity ratios range from 0.006 to 113. (239)Pu/(238)U mass ratios for the saturated zone are <2 x 10(-14), and Pu mobility in the saturated zone is >1000 times lower than the U mobility. Saturated zone mobility decreases in the order (238)U approximately (226)Ra > (230)Th approximately (239)Pu. Radium and thorium appear to have higher mobility in the unsaturated zone based on U-series data from fractures and seepage water near the deposit.

  13. Uranium-series constraints on radionuclide transport and groundwater flow at the Nopal I uranium deposit, Sierra Pena Blanca, Mexico

    SciTech Connect

    Goldstein, S.J.; Abdel-Fattah, A.I.; Murrell, M.T.; Dobson, P.F.; Norman, D.E.; Amato, R.S.; Nunn, A. J.

    2009-10-01

    Uranium-series data for groundwater samples from the Nopal I uranium ore deposit were obtained to place constraints on radionuclide transport and hydrologic processes for a nuclear waste repository located in fractured, unsaturated volcanic tuff. Decreasing uranium concentrations for wells drilled in 2003 are consistent with a simple physical mixing model that indicates that groundwater velocities are low ({approx}10 m/y). Uranium isotopic constraints, well productivities, and radon systematics also suggest limited groundwater mixing and slow flow in the saturated zone. Uranium isotopic systematics for seepage water collected in the mine adit show a spatial dependence which is consistent with longer water-rock interaction times and higher uranium dissolution inputs at the front adit where the deposit is located. Uranium-series disequilibria measurements for mostly unsaturated zone samples indicate that {sup 230}Th/{sup 238}U activity ratios range from 0.005-0.48 and {sup 226}Ra/{sup 238}U activity ratios range from 0.006-113. {sup 239}Pu/{sup 238}U mass ratios for the saturated zone are <2 x 10{sup -14}, and Pu mobility in the saturated zone is >1000 times lower than the U mobility. Saturated zone mobility decreases in the order {sup 238}U{approx}{sup 226}Ra > {sup 230}Th{approx}{sup 239}Pu. Radium and thorium appear to have higher mobility in the unsaturated zone based on U-series data from fractures and seepage water near the deposit.

  14. Flow and Radionuclide Transport Models of the Unsaturated Zone at the Nevada National Security Site: Examples from Yucca Flat and Rainier Mesa

    NASA Astrophysics Data System (ADS)

    Kwicklis, E. M.; Viswanathan, H. S.; Levitt, D. G.; Dash, Z.; Gable, C. W.; Lu, Z.; Dai, Z.; Zyvoloski, G.; Miller, T. A.

    2011-12-01

    The former Nevada Test Site (now the Nevada National Security Site) hosted 828 underground nuclear explosions between 1951 and 1992, leaving an estimated 1.3e+08 curies of tritium, fission products, activation products and unspent fuel in the subsurface when the nuclear test moratorium was adopted in September, 1992. In two former testing areas of the Nevada National Security Site - Yucca Flat and Rainier Mesa- a significant fraction of the initial radionuclide inventory was introduced from nuclear tests with working points in the unsaturated zone. In Yucca Flat, an arid, low-elevation alluvium-filled basin where most tests were conducted in vertical shafts, unsaturated flow and transport models indicate that radionuclide migration to the water table is most likely where overlying subsidence craters receive significant infiltration from overland flow during infrequent runoff events. These craters tend to be located along the perimeter of the basin and have large contributing watersheds in the surrounding hills. At Rainier Mesa, a wetter, high-elevation remnant of a once more extensive volcanic plateau, most tests were conducted at the ends of horizontal drifts in the vicinity of local perched water zones. Unsaturated flow and transport models of one of the larger tunnel complexes (N-tunnel) indicate that despite relatively high infiltration rates on the mesa, radionuclide diffusion from the flowing fractures to the porous matrix may significantly attenuate radionuclide movement to the water table, depending on the assumed fracture attributes. Simulations show that the tunnel itself may be an important hydraulic feature that connects radionuclide sources to sub-vertical faults that are assumed to extend to the water table.

  15. Simulations of Groundwater Flow and Radionuclide Transport in the Vadose and Saturated Zones beneath Area G, Los Alamos National Laboratory

    SciTech Connect

    Kay H. Birdsell; Kathleen M. Bower; Andrew V. Wolfsberg; Wendy E. Soll; Terry A. Cherry; Tade W. Orr

    1999-07-01

    Numerical simulations are used to predict the migration of radionuclides from the disposal units at Material Disposal Area G through the vadose zone and into the main aquifer in support of a radiological performance assessment and composite analysis for the site. The calculations are performed with the finite element code, FEHM. The transport of nuclides through the vadose zone is computed using a three-dimensional model that describes the complex mesa top geology of the site. The model incorporates the positions and inventories of thirty-four disposal pits and four shaft fields located at Area G as well as those of proposed future pits and shafts. Only three nuclides, C-14, Tc-99, and I-129, proved to be of concern for the groundwater pathway over a 10,000-year period. The spatial and temporal flux of these three nuclides from the vadose zone is applied as a source term for the three-dimensional saturated zone model of the main aquifer that underlies the site. The movement of these nuclides in the aquifer to a downstream location is calculated, and aquifer concentrations are converted to doses. Doses related to aquifer concentrations are six or more orders of magnitude lower than allowable Department of Energy performance objectives for low-level radioactive waste sites. Numerical studies were used to better understand vadose-zone flow through the dry mesa-top environment at Area G. These studies helped define the final model used to model flow and transport through the vadose zone. The study of transient percolation indicates that a steady flow vadose-zone model is adequate for computing contaminant flux to the aquifer. The fracture flow studies and the investigation of the effect of basalt and pumice properties helped us define appropriate hydrologic properties for the modeling. Finally, the evaporation study helped to justify low infiltration rates.

  16. Structure and function of subsurface microbial communities affecting radionuclide transport and bio-immobilization

    SciTech Connect

    Stucki, Joseph William

    2013-05-13

    The purpose of this study was to provide comparative information regarding the changes in clay structure that occur due to biotic or abiotic reduction, as probed by variable-temperature Mössbauer spectroscopy.

  17. Radionuclide and colloid transport in the Culebra Dolomite and associated complementary cumulative distribution functions in the 1996 performance assessment for the Waste Isolation Pilot Plant

    SciTech Connect

    RAMSEY, JAMES L.; BLAINE,R.; GARNER,J.W.; HELTON,JON CRAIG; JOHNSON,J.D.; SMITH,L.N.; WALLACE,M.

    2000-05-22

    The following topics related to radionuclide and colloid transport in the Culebra Dolomite in the 1996 performance assessment for the Waste Isolation Pilot Plant (WIPP) are presented: (1) mathematical description of models, (2) uncertainty and sensitivity analysis results arising from subjective (i.e., epistemic) uncertainty for individual releases, and (3) construction of complementary cumulative distribution functions (CCDFs) arising from stochastic (i.e., aleatory) uncertainty. The presented results indicate that radionuclide and colloid transport in the Culebra Dolomite does not constitute a serious threat to the effectiveness of the WIPP as a disposal facility for transuranic waste. Even when the effects of uncertain analysis inputs are taken into account, no radionuclide transport to the boundary with the accessible environment was observed; thus the associated CCDFs for comparison with the boundary line specified in the US Environmental Protection Agency's standard for the geologic disposal of radioactive waste (40 CFR 191, 40 CFR 194) are degenerate in the sense of having a probability of zero of exceeding a release of zero.

  18. Mesoscale Backtracking by Means of Atmospheric Transport Modeling of Xenon Plumes Measured by Radionuclide Gas Stations

    NASA Astrophysics Data System (ADS)

    Armand, P. P.; Achim, P.; Taffary, T.

    2006-12-01

    The monitoring of atmospheric radioactive xenon concentration is performed for nuclear safety regulatory requirements. It is also planned to be used for the detection of hypothetical nuclear tests in the framework of the Comprehensive nuclear-Test-Ban Treaty (CTBT). In this context, the French Atomic Energy Commission designed a high sensitive and automated fieldable station, named SPALAX, to measure the activity concentrations of xenon isotopes in the atmosphere. SPALAX stations were set up in Western Europe and have been operated quite continuously for three years or more, detecting principally xenon-133 and more scarcely xenon-135, xenon-133m and xenon-131m. There are around 150 nuclear power plants in the European Union, research reactors, reprocessing plants, medical production and application facilities releasing radioactive xenon in normal or incidental operations. A numerical study was carried out aiming to explain the SPALAX measurements. The mesoscale Atmospheric Transport Modelling involves the MM5 suite (PSU- NCAR) to predict the wind fields on nested domains, and FLEXPART, a 3D Lagrangian particle dispersion code, used to simulate the backward transport of xenon plumes detected by the SPALAX. For every event of detection, at least one potential xenon source has a significant efficiency of emission. The identified likely sources are located quite close to the SPALAX stations (some tens of kilometres), or situated farther (a few hundreds of kilometres). A base line of some mBq per cubic meter in xenon-133 is generated by the nuclear power plants. Peaks of xenon-133 ranging from tens to hundreds of mBq per cubic meter originate from a radioisotope production facility. The calculated xenon source terms required to obtain the SPALAX measurements are discussed and seem consistent with realistic emissions from the xenon sources in Western Europe.

  19. Review and analysis of parameters for assessing transport of environmentally released radionuclides through agriculture

    SciTech Connect

    Baes, C.F. III; Sharp, R.D.; Sjoreen, A.L.; Shor, R.W.

    1984-09-01

    Most of the default parameters incorporated into the TERRA computer code are documented including a literature review and systematic analysis of element-specific transfer parameters B/sub v/, B/sub r/, F/sub m/, F/sub f/, and K/sub d/. This review and analysis suggests default values which are consistent with the modeling approaches taken in TERRA and may be acceptable for most assessment applications of the computer code. However, particular applications of the code and additional analysis of elemental transport may require alternative default values. Use of the values reported herein in other computer codes simulating terrestrial transport is not advised without careful interpretation of the limitations and scope these analyses. An approach to determination of vegetation-specific interception fractions is also discussed. The limitations of this approach are many, and its use indicates the need for analysis of deposition, interception, and weathering processes. Judgement must be exercised in interpretation of plant surface concentrations generated. Finally, the location-specific agricultural, climatological, and population parameters in the default SITE data base documented. These parameters are intended as alternatives to average values currently used. Indeed, areas in the United States where intensive crop, milk, or beef production occurs will be reflected in the parameter values as will areas where little agricultural activity occurs. However, the original information sources contained some small error and the interpolation and conversion methods used will add more. Parameters used in TERRA not discussed herein are discussed in the companion report to this one - ORNL-5785. In the companion report the models employed in and the coding of TERRA are discussed. These reports together provide documentation of the TERRA code and its use in assessments. 96 references, 78 figures, 21 tables.

  20. Variability in dose estimates associated with the food-chain transport and ingestion of selected radionuclides

    SciTech Connect

    Hoffman, F.O.; Gardner, R.H.; Eckerman, K.F.

    1982-06-01

    Dose predictions for the ingestion of /sup 90/Sr and /sup 137/Cs, using aquatic and terrestrial food chain transport models similar to those in the Nuclear Regulatory Commission's Regulatory Guide 1.109, are evaluated through estimating the variability of model parameters and determining the effect of this variability on model output. The variability in the predicted dose equivalent is determined using analytical and numerical procedures. In addition, a detailed discussion is included on /sup 90/Sr dosimetry. The overall estimates of uncertainty are most relevant to conditions where site-specific data is unavailable and when model structure and parameter estimates are unbiased. Based on the comparisons performed in this report, it is concluded that the use of the generic default parameters in Regulatory Guide 1.109 will usually produce conservative dose estimates that exceed the 90th percentile of the predicted distribution of dose equivalents. An exception is the meat pathway for /sup 137/Cs, in which use of generic default values results in a dose estimate at the 24th percentile. Among the terrestrial pathways of exposure, the non-leafy vegetable pathway is the most important for /sup 90/Sr. For /sup 90/Sr, the parameters for soil retention, soil-to-plant transfer, and internal dosimetry contribute most significantly to the variability in the predicted dose for the combined exposure to all terrestrial pathways. For /sup 137/Cs, the meat transfer coefficient the mass interception factor for pasture forage, and the ingestion dose factor are the most important parameters. The freshwater finfish bioaccumulation factor is the most important parameter for the dose prediction of /sup 90/Sr and /sup 137/Cs transported over the water-fish-man pathway.

  1. Resuspension and atmospheric transport of radionuclides due to wildfires near the Chernobyl Nuclear Power Plant in 2015: An impact assessment

    PubMed Central

    Evangeliou, N.; Zibtsev, S.; Myroniuk, V.; Zhurba, M.; Hamburger, T.; Stohl, A.; Balkanski, Y.; Paugam, R.; Mousseau, T. A.; Møller, A. P.; Kireev, S. I.

    2016-01-01

    In April and August 2015, two major fires in the Chernobyl Exclusion Zone (CEZ) caused concerns about the secondary radioactive contamination that might have spread over Europe. The present paper assessed, for the first time, the impact of these fires over Europe. About 10.9 TBq of 137Cs, 1.5 TBq of 90Sr, 7.8 GBq of 238Pu, 6.3 GBq of 239Pu, 9.4 GBq of 240Pu and 29.7 GBq of 241Am were released from both fire events corresponding to a serious event. The more labile elements escaped easier from the CEZ, whereas the larger refractory particles were removed more efficiently from the atmosphere mainly affecting the CEZ and its vicinity. During the spring 2015 fires, about 93% of the labile and 97% of the refractory particles ended in Eastern European countries. Similarly, during the summer 2015 fires, about 75% of the labile and 59% of the refractory radionuclides were exported from the CEZ with the majority depositing in Belarus and Russia. Effective doses were above 1 mSv y−1 in the CEZ, but much lower in the rest of Europe contributing an additional dose to the Eastern European population, which is far below a dose from a medical X-ray. PMID:27184191

  2. Resuspension and atmospheric transport of radionuclides due to wildfires near the Chernobyl Nuclear Power Plant in 2015: An impact assessment.

    PubMed

    Evangeliou, N; Zibtsev, S; Myroniuk, V; Zhurba, M; Hamburger, T; Stohl, A; Balkanski, Y; Paugam, R; Mousseau, T A; Møller, A P; Kireev, S I

    2016-05-17

    In April and August 2015, two major fires in the Chernobyl Exclusion Zone (CEZ) caused concerns about the secondary radioactive contamination that might have spread over Europe. The present paper assessed, for the first time, the impact of these fires over Europe. About 10.9 TBq of (137)Cs, 1.5 TBq of (90)Sr, 7.8 GBq of (238)Pu, 6.3 GBq of (239)Pu, 9.4 GBq of (240)Pu and 29.7 GBq of (241)Am were released from both fire events corresponding to a serious event. The more labile elements escaped easier from the CEZ, whereas the larger refractory particles were removed more efficiently from the atmosphere mainly affecting the CEZ and its vicinity. During the spring 2015 fires, about 93% of the labile and 97% of the refractory particles ended in Eastern European countries. Similarly, during the summer 2015 fires, about 75% of the labile and 59% of the refractory radionuclides were exported from the CEZ with the majority depositing in Belarus and Russia. Effective doses were above 1 mSv y(-1) in the CEZ, but much lower in the rest of Europe contributing an additional dose to the Eastern European population, which is far below a dose from a medical X-ray.

  3. Resuspension and atmospheric transport of radionuclides due to wildfires near the Chernobyl Nuclear Power Plant in 2015: An impact assessment

    NASA Astrophysics Data System (ADS)

    Evangeliou, N.; Zibtsev, S.; Myroniuk, V.; Zhurba, M.; Hamburger, T.; Stohl, A.; Balkanski, Y.; Paugam, R.; Mousseau, T. A.; Møller, A. P.; Kireev, S. I.

    2016-05-01

    In April and August 2015, two major fires in the Chernobyl Exclusion Zone (CEZ) caused concerns about the secondary radioactive contamination that might have spread over Europe. The present paper assessed, for the first time, the impact of these fires over Europe. About 10.9 TBq of 137Cs, 1.5 TBq of 90Sr, 7.8 GBq of 238Pu, 6.3 GBq of 239Pu, 9.4 GBq of 240Pu and 29.7 GBq of 241Am were released from both fire events corresponding to a serious event. The more labile elements escaped easier from the CEZ, whereas the larger refractory particles were removed more efficiently from the atmosphere mainly affecting the CEZ and its vicinity. During the spring 2015 fires, about 93% of the labile and 97% of the refractory particles ended in Eastern European countries. Similarly, during the summer 2015 fires, about 75% of the labile and 59% of the refractory radionuclides were exported from the CEZ with the majority depositing in Belarus and Russia. Effective doses were above 1 mSv y‑1 in the CEZ, but much lower in the rest of Europe contributing an additional dose to the Eastern European population, which is far below a dose from a medical X-ray.

  4. SIMULATING RADIONUCLIDE FATE AND TRANSPORT IN THE UNSATURATED ZONE: EVALUATION AND SENSITIVITY ANALYSES OF SELECT COMPUTER MODELS

    EPA Science Inventory

    Numerical, mathematical models of water and chemical movement in soils are used as decision aids for determining soil screening levels (SSLs) of radionuclides in the unsaturated zone. Many models require extensive input parameters which include uncertainty due to soil variabil...

  5. Engineering biomineralised groundwater flow barriers for inhibiting radionuclide transport in fractured rocks

    NASA Astrophysics Data System (ADS)

    Blundell, N.; Cuthbert, M. O.; Riley, M. S.; Handley-Sidhu, S.; Renshaw, J. C.

    2012-04-01

    Microbially induced carbonate precipitation (MICP) is a promising engineering solution for inhibiting pollution transport in fractured rocks through permeability reduction of fine aperture fractures surrounding nuclear decommissioning sites or repositories. However, although many batch and column studies of MICP within porous media have been carried out, the method has yet to be successfully applied within fractured materials and upscaled to block and field scales to demonstrate its potential utility. This paper presents results of laboratory MICP experiments within artificial granite-perspex fractures (30 cm x 10 cm x 150 µm) under flowing conditions using ureolytic bacteria and a 'cementing solution' comprising dissolved urea and calcium chloride. A variety of injection combinations and bacterial/solute concentrations were trialled and changes in hydraulic conductivity of the fractures were measured over time. Injected bacteria were successfully 'fixed' by adding sufficient calcium chloride to encourage flocculation and hence mechanical filtration to trap the bacteria. Observed reductions in hydraulic conductivity of up to 3 orders of magnitude were achieved after 4 x 4 hour phases of injection with a decreasing mass of precipitate with distance from the inlet manifold. Although the results are very promising, a remaining challenge for successful upscaling of the technique to the field scale is in controlling the spatial distribution of bacterial fixing and precipitation to enable sealing of fractures at larger distances from the point of injection. In comparison to existing grouting techniques, MICP has the advantage of being low viscosity and is therefore potentially useful for very fine scale fractures while also potentially providing greater mechanical strength.

  6. Enhanced serotonin transporter function during depression in seasonal affective disorder.

    PubMed

    Willeit, Matthäus; Sitte, Harald H; Thierry, Nikolaus; Michalek, Klaus; Praschak-Rieder, Nicole; Zill, Peter; Winkler, Dietmar; Brannath, Werner; Fischer, Michael B; Bondy, Brigitta; Kasper, Siegfried; Singer, Ernst A

    2008-06-01

    Decreased synaptic serotonin during depressive episodes is a central element of the monoamine hypothesis of depression. The serotonin transporter (5-HTT, SERT) is a key molecule for the control of synaptic serotonin levels. Here we aimed to detect state-related alterations in the efficiency of 5-HTT-mediated inward and outward transport in platelets of drug-free depressed patients suffering from seasonal affective disorder (SAD). 5-HTT turnover rate, a measure for the number of inward transport events per minute, and tyramine-induced, 5-HTT-mediated outward transport were assessed at baseline, after 4 weeks of bright light therapy, and in summer using a case-control design in a consecutive sample of 73 drug-free depressed patients with SAD and 70 nonseasonal healthy controls. Patients were drug-naive or medication-free for at least 6 months prior to study inclusion, females patients were studied in the follicular phase of the menstrual cycle. All participants were genotyped for a 5-HTT-promoter polymorphism (5-HTTLPR) to assess the influence of this polymorphism on 5-HTT parameters. Efficiency of 5-HTT-mediated inward (p=0.014) and outward (p=0.003) transport was enhanced in depressed patients. Both measures normalized toward control levels after therapy and in natural summer remission. Changes in outward transport showed a clear correlation with treatment response (rho=0.421, p=0.001). Changes in inward transport were mediated by changes in 5-HTT transport efficiency rather than affinity or density. 5-HTTLPR was not associated with any of the 5-HTT parameters. In sum, we conclude that the 5-HTT is in a hyperfunctional state during depression in SAD and normalizes after light therapy and in natural summer remission.

  7. Atmospheric transport and deposition of radionuclides released after the Fukushima Dai-chi accident and resulting effective dose

    NASA Astrophysics Data System (ADS)

    Marzo, Giuseppe A.

    2014-09-01

    On 11 March 2011 an earthquake off the Pacific coast of the Fukushima prefecture generated a tsunami that hit Fukushima Dai-ichi and Fukushima Da-ini Nuclear Power Plants. From 12 March a significant amount of radioactive material was released into the atmosphere and dispersed worldwide. Among the most abundant radioactive species released were iodine and cesium isotopes. By means of an atmospheric dispersion Lagrangian code and publicly available meteorological data, the atmospheric dispersion of 131I, 134Cs, and 137Cs have been simulated for three months after the event with a spatial resolution of 0.5° × 0.5° globally. The simulation has been validated by comparison to publicly available measurements collected in 206 locations worldwide. Sensitivity analysis shows that release height of the radionuclides, wet deposition velocity, and source term are the parameters with the most impact on the simulation results. The simulation shows that the radioactive plume, consisting of about 200 PBq by adding contributions from 131I, 134Cs, and 137Cs, has been transported over the entire northern hemisphere depositing up to 1.2 MBq m-2 nearby the NPPs to less than 20 Bq m-2 in Europe. The consequent effective dose to the population over a 50-year period, calculated by considering both external and internal pathways of exposure, is found to be about 40 mSv in the surroundings of Fukushima Dai-ichi, while other countries in the northern hemisphere experienced doses several orders of magnitude lower suggesting a small impact on the population health elsewhere.

  8. Vegetation-derived insights on the mobilization and potential transport of radionuclides from the Nopal I natural analog site, Mexico

    SciTech Connect

    Leslie, B.W.; Pickett, D.A.; Pearcy, E.C.

    1999-07-01

    The Nopal I uranium (U) deposit, Pena Blanca, Mexico is a source term and contaminant transport natural analog to the proposed high-level nuclear waste repository at Yucca Mountain, Nevada. In an attempt to characterize the mobilization and potential transport of radionuclides in the unsaturated zone at the Nopal I deposit, vegetation growing on ore piles was analyzed for {sup 238}U, {sup 235}U, and {sup 232}Th decay-series isotopes. Specimens of Phacelia robusta growing on high-grade piles of U ore were collected and analyzed by alpha autoradiography, and by alpha and gamma spectrometry. Activities for U, thorium (Th), and radium (Ra) isotopes (Bq/kg dried plant) were 300, 1,000, and 7,000 for {sup 238}U, {sup 230}Th, and {sup 226}Ra, respectively. The {sup 226}Ra activities in these specimens are among the highest ever measured for plants; furthermore, the plant-to-soil {sup 226}Ra concentration ratio is higher than expected. These results demonstrate the large mobility and bio-availability of Ra in the Nopal I environment, and support previous indications of recent loss of {sup 226}Ra from the ore body. Comparison between the activities of {sup 238}U and {sup 232}Th decay-chain Th isotopes in the plants and in the ore substrate indicate that relative mobilization into pore solutions of {sup 228}Th > {sup 230}Th > {sup 232}Th, in a ratio of about 50--25:4:1, respectively. The similarity of the plant's {sup 234}U/{sup 238}U activity ratio ({approximately}1.2) to that of a caliche deposit that formed adjacent to the Nopal ore body around 54 ka suggests the {sup 234}U/{sup 238}U activity ratio of U released from the ore is approximately 1.2. The U and {sup 226}Ra isotope activities of the plants and ore substrate, and solubility considerations, are used to assess a source term model of the potential Yucca Mountain repository. These results suggest the use of a natural analog source term model in performance assessments may be non-conservative.

  9. Accumulation of radionuclides by plants as a monitor system.

    PubMed Central

    Koranda, J J; Robison, W L

    1978-01-01

    The accumulation of radionuclides by plants acting as a monitoring system in the environment may occur by two modes; foliar absorption by the leaves and shoot of the plant, or by root uptake from the soil. Data on plant accumulation of radionuclides may be obtained from studies of fission product radionuclides deposited as worldwide fallout, and from tracer studies of plant physiology. The epidermal features of plant foliage may exert an effect upon particle retention by leaves, and subsequent uptake of radionuclides from the surface. The transport of radionuclides across the cuticle and epidermis of plant leaves is determined in part by the anatomy of the leaf, and by physiological factors. The foliar uptake of fallout radionuclides, 99Sr, 131I, and 137Cs, is described with examples from the scientific literature. The environmental half-life of 131I, for example, is considerably shorter than its physical half-life because of physical and biological factors which may produce a half-life as short as 0.23/day. 99Sr and 137Cs are readily taken up by the leaf, but 137Cs undergoes more translocation into fruit and seeds than 99Sr which tends to remain in the plant part in which it was initially absorbed. Soil-root uptake is conditioned primarily by soil chemical and physical factors which may selectively retain a radionuclide, such as 137Cs. The presence of organic matter, inorganic colloids (clay), and competing elements will strongly affect the uptake of 99Sr and 137Cs by plants from the soil. The role of plants as monitors of radionuclides is twofold: as monitors of recent atmospheric releases of radionuclides; and as indicators of the long-term behavior of aged deposits of radionuclides in the soil. PMID:367767

  10. Transuranic radionuclides dispersed into the environment at accident sites, a bibliography

    SciTech Connect

    Stoker, A.C.; Noshkin, V.E.; Wong, K.M.

    1994-07-01

    The purpose of this project was to compile a bibliography of references containing environmental transuranic radionuclide data. The authors intent was to identify those parameters affecting transuranic radionuclide transport that may be generic and those that may be dependent on chemical form and/or environmental conditions. An understanding of the unique characteristics and similarities between source terms and environmental conditions relative to transuranic radionuclide transport and cycling will provide the ability to assess and predict the long term impact on man and the environment. An additional goal of the literature review, was to extract the ranges of environmental transuranic radionuclide data from the identified references for inclusion in a data base. Related to source term, these ranges of data can be used to calculate the dose to man from the radionuclides, and to perform uncertainty analyses on these dose assessments.

  11. Radionuclide Generators

    NASA Astrophysics Data System (ADS)

    Rösch, F.; Knapp, F. F. (Russ)

    Radionuclide generator systems continue to play a key role in providing both diagnostic and therapeutic radionuclides for various applications in nuclear medicine, oncology, and interventional cardiology. Although many parent/daughter pairs have been evaluated as radionuclide generator systems, there are a relatively small number of generators, which are currently in routine clinical and research use. Essentially every conceivable approach has been used for parent/separation strategies, including sublimation, thermochromatographic separation, solvent extraction, and adsorptive column chromatography. The most widely used radionuclide generator for clinical applications is the 99Mo/99mTc generator system, but recent years have seen an enormous increase in the use of generators to provide therapeutic radionuclides, which has paralleled the development of complementary technologies for targeting agents for therapy and in the general increased interest in the use of unsealed therapeutic radioactive sources. More recently, use of the 68Ge/68Ga generator is showing great potential as a source of positron-emitting 68Ga for positron emission tomography (PET)/CT imaging. Key advantages for the use of radionuclide generators include reasonable costs, the convenience of obtaining the desired daughter radionuclide on demand, and availability of the daughter radionuclide in high specific activity, no-carrier added form.

  12. Heterogeneous processes affecting metal ion transport in the presence of organic ligands: Reactive transport modeling

    NASA Astrophysics Data System (ADS)

    Kantar, Cetin

    2007-04-01

    The development of models to accurately simulate metal ion transport through saturated systems under variable chemical conditions, e.g., in systems containing organic ligands (L) such as natural organic matter (NOM), has two essential aspects: (1) establishing the ability to simulate metal ion sorption to aquifer solids over a range of metal/ligand ratios; and (2) to incorporate this ability to simulate metal speciation over a range in chemical conditions (e.g., pH, ligand activity) into mass transport models. Modeling approaches to evaluate metal ion sorption and transport in the presence of NOM include: (1) isotherm-based transport models, and (2) multicomponent (MC) transport models. The accuracy of transport models depends on how well the chemical interactions affecting metal ion transport in the presence of organic ligands (e.g., metal/ligand complexation) are described in transport equations. The isotherm-based transport models often fail to accurately describe metal ion transport in the presence of NOM since these models treat NOM as a single solute despite the fact that NOM is a multicomponent mixture of subcomponents with different chemical and polyfunctional behavior. On the other hand, the calculations presented in this study suggest that a multicomponent reactive transport model, in conjunction with a mechanistic modeling approach for the description of metal ion binding by NOM in a manner conducive to the application of surface complexation modeling (SCM), can effectively be used as an important predictive tool in simulating metal ion sorption and transport under variable chemical conditions in the presence of NOM.

  13. Milestone M4FT-13LL0807071: International Collaboration - Radionuclide Interactions and Transport in Geologic Repository Environments - Pu Interaction with Bentonite

    SciTech Connect

    Begg, J D; Zavarin, M; Kersting, A B

    2013-11-13

    The focus of this project is to investigate radionuclide interactions with natural and engineered materials, specifically the mineral bentonite that will be used in EU repositories and possibly in US high-level waste repository designs. These experiments are designed to develop a mechanistic understanding of Pu interactions with representative mineral substrates under granitic chemical conditions. The sorption/desorption experiments cover a large range of Pu concentrations and will be compared to sorption/desorption experiment with montmorillonite. The experiments are being coordinated with the Colloid Formation and Migration (CFM) international project led by Karlsruhe Institute of Technology and located at the Grimsel Test Site underground research laboratory in Switzerland. Experiments will be completed by 8/15/2014. Milestone M4FT-13LL0807071 is a progress report on this effort. The research is addressing the following FEPs/needs identified in the R&D Roadmap: 2.2.09.05 - radionuclide speciation and solubility in host rock; 2.2.09.55 - sorption of dissolved radionuclides in host rock; 2.2.09.59 - colloidal transport in host rock.

  14. Effect of Selected Modeling Assumptions on Subsurface Radionuclide Transport Projections for the Potential Environmental Management Disposal Facility at Oak Ridge, Tennessee

    SciTech Connect

    Painter, Scott L.

    2016-06-28

    The Department of Energy’s Office of Environmental Management recently revised a Remedial Investigation/ Feasibility Study (RI/FS) that included an analysis of subsurface radionuclide transport at a potential new Environmental Management Disposal Facility (EMDF) in East Bear Creek Valley near Oak Ridge, Tennessee. The effect of three simplifying assumptions used in the RI/FS analyses are investigated using the same subsurface pathway conceptualization but with more flexible modeling tools. Neglect of vadose zone dispersion was found to be conservative or non-conservative, depending on the retarded travel time and the half-life. For a given equilibrium distribution coefficient, a relatively narrow range of half-life was identified for which neglect of vadose zone transport is non-conservative and radionuclide discharge into surface water is non-negligible. However, there are two additional conservative simplifications in the reference case that compensate for the non-conservative effect of neglecting vadose zone dispersion: the use of a steady infiltration rate and vadose zone velocity, and the way equilibrium sorption is used to represent transport in the fractured material of the saturated aquifer. With more realistic representations of all three processes, the RI/FS reference case was found to either provide a reasonably good approximation to the peak concentration or was significantly conservative (pessimistic) for all parameter combinations considered.

  15. Coupled Geochemical and Hydrological Processes Governing the Fate and Transport of Radionuclides and Toxic Metals Beneath the Hanford Tank Farms

    SciTech Connect

    Scott Fendorf; Phil Jardine

    2006-07-21

    The goal of this research was to provide an improved understanding and predictive capability of coupled hydrological and geochemical mechanisms that are responsible for the accelerated migration and immobilization of radionuclides and toxic metals in the badose zone beneath the Hanford Tank Farms.

  16. Radionuclide cisternogram

    MedlinePlus

    ... please enable JavaScript. A radionuclide cisternogram is a nuclear scan test. It is used to diagnose problems ... damage. The amount of radiation used during the nuclear scan is very small. Almost all of the ...

  17. Radionuclide transport and uptake in coastal aquatic ecosystems: a comparison of a 3D dynamic model and a compartment model.

    PubMed

    Erichsen, Anders Christian; Konovalenko, Lena; Møhlenberg, Flemming; Closter, Rikke Margrethe; Bradshaw, Clare; Aquilonius, Karin; Kautsky, Ulrik

    2013-05-01

    In safety assessments of underground radioactive waste repositories, understanding radionuclide fate in ecosystems is necessary to determine the impacts of potential releases. Here, the reliability of two mechanistic models (the compartmental K-model and the 3D dynamic D-model) in describing the fate of radionuclides released into a Baltic Sea bay is tested. Both are based on ecosystem models that simulate the cycling of organic matter (carbon). Radionuclide transfer is linked to adsorption and flows of carbon in food chains. Accumulation of Th-230, Cs-135, and Ni-59 in biological compartments was comparable between the models and site measurements despite differences in temporal resolution, biological state variables, and partition coefficients. Both models provided confidence limits for their modeled concentration ratios, an improvement over models that only estimate means. The D-model enables estimates at high spatio-temporal resolution. The K-model, being coarser but faster, allows estimates centuries ahead. Future developments could integrate the two models to take advantage of their respective strengths.

  18. Concentration of radionuclides in hydrosphere affected by Temelín Nuclear Power Plant in Czech Republic.

    PubMed

    Hanslík, E; Ivanovová, D; Jedináková-Krízová, V; Juranová, E; Simonek, P

    2009-07-01

    The paper presents results of a long-term field study of the possible impact of Temelín NPP on the Vltava and Elbe Rivers. The study was divided into 2 stages: before and after the operation of the NPP. The main goal of the investigation before the operation (1989-2000) was to determine the background levels of radionuclides resulting from the tests of nuclear weapons and the Chernobyl accident for different components of the environment. The paper discusses also the risk of a river radioactive contamination due to the tritium discharges in wastewater from Temelín NPP. During the operation period of 2001-2006, the results of the monitoring did not detect any impact of Temelín NPP on the concentrations of activation and fission products in the hydrosphere, apart from tritium. The annual average tritium concentrations in the Vltava River correspond with the previously calculated predictions for the conditions of the average and minimum guaranteed flows. The maximum concentration of tritium of 26.6 Bq/l in Vltava River at Prague was observed after dry period in 2003.

  19. Tau phosphorylation affects its axonal transport and degradation

    PubMed Central

    Rodríguez-Martín, Teresa; Cuchillo-Ibáñez, Inmaculada; Noble, Wendy; Nyenya, Fanon; Anderton, Brian H.; Hanger, Diane P.

    2013-01-01

    Phosphorylated forms of microtubule-associated protein tau accumulate in neurofibrillary tangles in Alzheimer's disease. To investigate the effects of specific phosphorylated tau residues on its function, wild type or phosphomutant tau was expressed in cells. Elevated tau phosphorylation decreased its microtubule binding and bundling, and increased the number of motile tau particles, without affecting axonal transport kinetics. In contrast, reducing tau phosphorylation enhanced the amount of tau bound to microtubules and inhibited axonal transport of tau. To determine whether differential tau clearance is responsible for the increase in phosphomimic tau, we inhibited autophagy in neurons which resulted in a 3-fold accumulation of phosphomimic tau compared with wild type tau, and endogenous tau was unaffected. In autophagy-deficient mouse embryonic fibroblasts, but not in neurons, proteasomal degradation of phosphomutant tau was also reduced compared with wild type tau. Therefore, autophagic and proteasomal pathways are involved in tau degradation, with autophagy appearing to be the primary route for clearing phosphorylated tau in neurons. Defective autophagy might contribute to the accumulaton of tau in neurodegenerative diseases. PMID:23601672

  20. Radionuclide transport from soil to air, native vegetation, kangaroo rats and grazing cattle on the Nevada test site

    SciTech Connect

    Gilbert, R.O.; Shinn, J.H.; Essington, E.H.; Tamura, T.; Romney, E.M.; Moor, K.S.; O'Farrell, T.P.

    1988-12-01

    Between 1970 and 1986 the Nevada Applied Ecology Group (NAEG), U.S. Department of Energy, conducted environmental radionuclide studies at weapons-testing sites on or adjacent to the Nevada Test Site. In this paper, NAEG studies conducted at two nuclear (fission) sites (NS201, NS219) and two nonnuclear (nonfission) sites (Area 13 (Project 57) and Clean Slate 2) are reviewed, synthesized and compared regarding (1) soil particle-size distribution and physical-chemical characteristics of 239 + 240Pu-bearing radioactive particles, (2) 239 + 240Pu resuspension rates and (3) transuranic and fission-product radionuclide transfers from soil to native vegetation, kangaroo rats and grazing cattle. The data indicate that transuranic radionuclides were transferred more readily on the average from soil to air, the external surfaces of native vegetation and to tissues of kangaroo rats at Area 13 than at NS201 or NS219. The 239 + 240Pu resuspension factor for undisturbed soil at Area 13 was three to four orders-of-magnitude larger than at NS201 and NS219, the geometric mean (GM) vegetation-over-soil 239 + 240Pu concentration ratio was from ten to 100 times larger than at NS201, and the GM GI-over-soil, carcass-over-soil and pelt-over-soil 239 + 240Pu ratios for kangaroo rats were about ten times larger than at NS201. These results are consistent with the finding that Area 13, compared with NS201 or NS219, has a higher percentage of radioactivity associated with smaller soil particles and a larger percentage of resuspendable and respirable soil. However, the resuspension factor increased by a factor of 27 at NS201 when the surface soil was disturbed, and by a factor of 12 at NS219 following a wildfire.

  1. Initial Radionuclide Inventories

    SciTech Connect

    H. Miller

    2004-09-19

    The purpose of this analysis is to provide an initial radionuclide inventory (in grams per waste package) and associated uncertainty distributions for use in the Total System Performance Assessment for the License Application (TSPA-LA) in support of the license application for the repository at Yucca Mountain, Nevada. This document is intended for use in postclosure analysis only. Bounding waste stream information and data were collected that capture probable limits. For commercially generated waste, this analysis considers alternative waste stream projections to bound the characteristics of wastes likely to be encountered using arrival scenarios that potentially impact the commercial spent nuclear fuel (CSNF) waste stream. For TSPA-LA, this radionuclide inventory analysis considers U.S. Department of Energy (DOE) high-level radioactive waste (DHLW) glass and two types of spent nuclear fuel (SNF): CSNF and DOE-owned (DSNF). These wastes are placed in two groups of waste packages: the CSNF waste package and the codisposal waste package (CDSP), which are designated to contain DHLW glass and DSNF, or DHLW glass only. The radionuclide inventory for naval SNF is provided separately in the classified ''Naval Nuclear Propulsion Program Technical Support Document'' for the License Application. As noted previously, the radionuclide inventory data presented here is intended only for TSPA-LA postclosure calculations. It is not applicable to preclosure safety calculations. Safe storage, transportation, and ultimate disposal of these wastes require safety analyses to support the design and licensing of repository equipment and facilities. These analyses will require radionuclide inventories to represent the radioactive source term that must be accommodated during handling, storage and disposition of these wastes. This analysis uses the best available information to identify the radionuclide inventory that is expected at the last year of last emplacement, currently identified as

  2. Flow and radionuclide transport from rock to surface systems: characterization and modelling of potential repository sites in Sweden

    SciTech Connect

    Werner, Kent; Bosson, Emma; Berglund, Sten

    2007-07-01

    The safety assessments of potential geological repositories for spent nuclear fuel in Sweden are supported by modelling of groundwater flow in rock, to predict locations (exit points) where radionuclides from the deep repository may enter land, surface waters and associated ecosystems above the rock. This modelling includes detailed rock descriptions, but simplifies the upper part of the flow domain, including representations of meteorological processes and interactions with hydrological objects at the surface. Using the Laxemar candidate site as example, this paper investigates some potentially important consequences of these simplifications. Specifically, it compares particle tracking results obtained by a deep-rock groundwater flow model (CONNECTFLOW) and by MIKE SHE-MIKE 11, which contains detailed descriptions of near-surface/surface water flow. Overall, the models predict similar exit point patterns, occurring as clusters along streams in valleys, at a lake, and in sea bays. However, on a detailed level there are some prediction differences, which may be of importance for biosphere-focused safety assessments. CONNECTFLOW essentially predicts flow paths through the repository that follow fractures and deformation zones, outcropping in valleys. In comparison, MIKE SHE-MIKE 11 provides more detailed information on near-surface water flow paths, including the associated exit points and inputs to assessments of radionuclide retention. (authors)

  3. Seismic reflection characteristics of naturally-induced subsidence affecting transportation

    USGS Publications Warehouse

    Miller, R.D.; Xia, J.; Steeples, D.W.

    2009-01-01

    High-resolution seismic reflections have been used effectively to investigate sinkholes formed from the dissolution of a bedded salt unit found throughout most of Central Kansas. Surface subsidence can have devastating effects on transportation structures. Roads, rails, bridges, and pipelines can even be dramatically affected by minor ground instability. Areas susceptible to surface subsidence can put public safety at risk. Subsurface expressions significantly larger than surface depressions are consistently observed on seismic images recorded over sinkholes in Kansas. Until subsidence reaches the ground surface, failure appears to be controlled by compressional forces evidenced by faults with reverse orientation. Once a surface depression forms or dissolution of the salt slows or stops, subsidence structures are consistent with a tensional stress environment with prevalent normal faults. Detecting areas of rapid subsidence potential, prior to surface failure, is the ultimate goal of any geotechnical survey where the ground surface is susceptible to settling. Seismic reflection images have helped correlate active subsidence to dormant paleofeatures, project horizontal growth of active sinkholes based on subsurface structures, and appraise the risk of catastrophic failure. ?? China University of Geosciences (Wuhan) and Springer-Verlag GmbH 2009.

  4. Radionuclide transport from soil to air, native vegetation, kangaroo rats and grazing cattle on the Nevada test site.

    PubMed

    Gilbert, R O; Shinn, J H; Essington, E H; Tamura, T; Romney, E M; Moor, K S; O'Farrell, T P

    1988-12-01

    Between 1970 and 1986 the Nevada Applied Ecology Group (NAEG), U.S. Department of Energy, conducted environmental radionuclide studies at weapons-testing sites on or adjacent to the Nevada Test Site. In this paper, NAEG studies conducted at two nuclear (fission) sites (NS201, NS219) and two nonnuclear (nonfission) sites (Area 13 [Project 57] and Clean Slate 2) are reviewed, synthesized and compared regarding (1) soil particle-size distribution and physical-chemical characteristics of 239 + 240Pu-bearing radioactive particles, (2) 239 + 240Pu resuspension rates and (3) transuranic and fission-product radionuclide transfers from soil to native vegetation, kangaroo rats and grazing cattle. The data indicate that transuranic radionuclides were transferred more readily on the average from soil to air, the external surfaces of native vegetation and to tissues of kangaroo rats at Area 13 than at NS201 or NS219. The 239 + 240Pu resuspension factor for undisturbed soil at Area 13 was three to four orders-of-magnitude larger than at NS201 and NS219, the geometric mean (GM) vegetation-over-soil 239 + 240Pu concentration ratio was from ten to 100 times larger than at NS201, and the GM GI-over-soil, carcass-over-soil and pelt-over-soil 239 + 240Pu ratios for kangaroo rats were about ten times larger than at NS201. These results are consistent with the finding that Area 13, compared with NS201 or NS219, has a higher percentage of radioactivity associated with smaller soil particles and a larger percentage of resuspendable and respirable soil. However, the resuspension factor increased by a factor of 27 at NS201 when the surface soil was disturbed, and by a factor of 12 at NS219 following a wildfire. The average (GM) concentration of 239 + 240Pu for the GI (and contents) of Area 13 kangaroo rats and for the rumen contents of beef cattle that grazed Area 13 were very similar (400 vs. 440 Bq kg-1 dry wt, respectively) although the variability between individuals was very large. The

  5. The Biogeochemistry of Pu and U: Distribution of Radionuclides Affected by Micro-Organisms and Their Siderophores, Reductants, and Exopolymers

    SciTech Connect

    Traina, Samuel J.

    2003-06-01

    Investigations to date focused on studying the dissolution of oxides and desorption of metals by the siderophore, Desferrioxamine B (DFB), with different metal ions adsorbed onto the solids. X-ray absorption spectroscopy (XAS) was used to probe the surface structural environment of sorbed metal ions. Results indicated that while DFB effectively dissolved iron oxides with different adsorbed metals, this process was also affected by the type of the metal adsorbed. For pure hematite, samples with adsorbed metals had less dissolved Fe by DFB than the one without. Different type of metal ion seemed to have no significant effects on Fe dissolution under these experimental conditions. This result suggested that while adsorbed metals blocked available surface sites on hematite surfaces for DFB causing less Fe release, Fe dissolution by DFB from the well crystalline structure of hematite was not affected by the adsorbed metal ions.

  6. Radionuclide removal

    SciTech Connect

    Sorg, T.J.

    1991-01-01

    The U.S. Environmental Protection Agency proposed new and revised regulations on radionuclide contaminants in drinking water in June 1991. During the 1980's, the Drinking Water Research Division, USEPA conducted a research program to evaluate various technologies to remove radium, uranium and radon from drinking water. The research consisted of laboratory and field studies conducted by USEPA, universities and consultants. The paper summarizes the results of the most significant projects completed. General information is also presented on the general chemistry of the three radionuclides. The information presented indicates that the most practical treatment methods for radium are ion exchange and lime-soda softening and reverse osmosis. The methods tested for radon are aeration and granular activated carbon and the methods for uranium are anion exchange and reverse osmosis.

  7. M4FT-16LL080303052-State of Knowledge for Colloid Facilitated Radionuclide Transport and Update on Actinide Diffusion in Bentonite Backfill

    SciTech Connect

    Zavarin, Mavrik; Joseph, C.

    2016-08-16

    This progress report (Level 4 Milestone Number M4FT-16LL080303052) summarizes research conducted at Lawrence Livermore National Laboratory (LLNL) within the Crystalline Disposal R&D Activity Number FT-16LL080303051 and Crystalline International Collaborations Activity Number FT-16LL080303061. The focus of this research is the interaction of radionuclides with Engineered Barrier System (EBS) and host rock materials at various physico-chemical conditions relevant to subsurface repository environments. They include both chemical and physical processes such as solubility, sorption, and diffusion. The colloid-facilitated transport effort focused on preparation of a draft manuscript summarizing the state of knowledge and parameterization of colloid-facilitated transport mechanisms in support of reactive transport and performance assessment models for generic crystalline repositories. This draft manuscript is being submitted as a level 3 milestone with LANL as the primary author. LLNL’s contribution to that effort is summarized only briefly in the present report. A manuscript summarizing long-term U(VI) diffusion experiments through bentonite backfill material was recently accepted for publication; the contents of that manuscript are summarized in the present report. The Np(IV) diffusion experiments were started mid-year and are ongoing. The completion of these experiments is planned for early FY17. Our progress in quantifying Np(IV) diffusion in bentonite backfill is summarized in the present report. Our involvement with the NEA TDB project was summarized in a recent Argillite Disposal activity report. It is not included in this report.

  8. Chemical speciation of radionuclides migrating in groundwaters

    SciTech Connect

    Robertson, D.; Schilk, A.; Abel, K.; Lepel, E.; Thomas, C.; Pratt, S.; Cooper, E.; Hartwig, P.; Killey, R.

    1994-04-01

    In order to more accurately predict the rates and mechanisms of radionuclide migration from low-level waste disposal facilities via groundwater transport, ongoing studies are being conducted at field sites at Chalk River Laboratories to identify and characterize the chemical speciation of mobile, long-lived radionuclides migrating in groundwaters. Large-volume water sampling techniques are being utilized to separate and concentrate radionuclides into particular, cationic, anionic, and nonionic chemical forms. Most radionuclides are migrating as soluble, anionic species that appear to be predominantly organoradionuclide complexes. Laboratory studies utilizing anion exchange chromatography have separated several anionically complexed radionuclides, e.g., {sup 60}Co and {sup 106}Ru, into a number of specific compounds or groups of compounds. Further identification of the anionic organoradionuclide complexes is planned utilizing high resolution mass spectrometry. Large-volume ultra-filtration experiments are characterizing the particulate forms of radionuclides being transported in these groundwaters.

  9. Radionuclide daughter inventory generator code: DIG

    SciTech Connect

    Fields, D.E.; Sharp, R.D.

    1985-09-01

    The Daughter Inventory Generator (DIG) code accepts a tabulation of radionuclide initially present in a waste stream, specified as amounts present either by mass or by activity, and produces a tabulation of radionuclides present after a user-specified elapsed time. This resultant radionuclide inventory characterizes wastes that have undergone daughter ingrowth during subsequent processes, such as leaching and transport, and includes daughter radionuclides that should be considered in these subsequent processes or for inclusion in a pollutant source term. Output of the DIG code also summarizes radionuclide decay constants. The DIG code was developed specifically to assist the user of the PRESTO-II methodology and code in preparing data sets and accounting for possible daughter ingrowth in wastes buried in shallow-land disposal areas. The DIG code is also useful in preparing data sets for the PRESTO-EPA code. Daughter ingrowth in buried radionuclides and in radionuclides that have been leached from the wastes and are undergoing hydrologic transport are considered, and the quantities of daughter radionuclide are calculated. Radionuclide decay constants generated by DIG and included in the DIG output are required in the PRESTO-II code input data set. The DIG accesses some subroutines written for use with the CRRIS system and accesses files containing radionuclide data compiled by D.C. Kocher. 11 refs.

  10. Effect of carbonate soil on transport and dose estimates from long-lived radionuclides at U. S. Pacific Test Site

    SciTech Connect

    Conrado, C.L.; Hamilton, T.F.; Robison, W.L.; Stoker, A.C.

    1998-09-01

    The United States conducted a series of nuclear tests from 1946 to 1958 at Bikini, a coral atoll, in the Marshall Islands (MI). The aquatic and terrestrial environments of the atoll are still contaminated with several long-lived radionuclides that were generated during testing. The four major radionuclides found in terrestrial plants and soils are Cesium-137 ({sup 137} Cs), Strontium-90 ({sup 90} Sr), Plutonium-239+ 240 ({sup 239+240}Pu) and Americium-241 ({sup 241}Am). {sup 137}Cs in the coral soils is more available for uptake by plants than {sup 137}Cs associated with continental soils of North America or Europe. Soil-to-plant {sup 137}Cs median concentration ratios (CR) (kBq kg{sup {minus}1} dry weight plant/kBq kg {sup {minus}1} dry weight soil) for tropical fruits and vegetables range between 0.8 and 36, much larger than the range of 0.005 to 0.5 reported for vegetation in temperate zones. Conversely, {sup 90}Sr median CRs range from 0.006 to 1.0 at the atoll versus a range from 0.02 to 3.0 for continental silica-based soils. Thus, the relative uptake of {sup 137}Cs and {sup 90}Sr by plants in carbonate soils is reversed from that observed in silica-based soils. The CRs for {sup 239+240}Pu and {sup 241}Am are very similar to those observed in continental soils. Values range from 10{sup {minus}6} to 10{sup {minus}4} for both {sup 239+240}Pu and {sup 241}Am. No significant difference is observed between the two in coral soil. The uptake of {sup 137}Cs by plants is enhanced because of the absence of mineral binding sites and the low concentration of potassium in the coral soil. {sup 137}Cs is bound to the organic fraction of the soil, whereas {sup 90}Sr, {sup 239+240}Pu and {sup 241}Am are primarily bound to soil particles. Assessment of plant uptake for {sup 137}Cs and {sup 90}Sr into locally grown food crops was a major contributing factor in (1) reliably predicting the radiological dose for returning residents, and (2) developing a strategy to limit the

  11. Microbial Transformations of Actinides and Other Radionuclides

    SciTech Connect

    Francis,A.J.; Dodge, C. J.

    2009-01-07

    Microorganisms can affect the stability and mobility of the actinides and other radionuclides released from nuclear fuel cycle and from nuclear fuel reprocessing plants. Under appropriate conditions, microorganisms can alter the chemical speciation, solubility and sorption properties and thus could increase or decrease the concentrations of radionuclides in solution in the environment and the bioavailability. Dissolution or immobilization of radionuclides is brought about by direct enzymatic action or indirect non-enzymatic action of microorganisms. Although the physical, chemical, and geochemical processes affecting dissolution, precipitation, and mobilization of radionuclides have been extensively investigated, we have only limited information on the effects of microbial processes and biochemical mechanisms which affect the stability and mobility of radionuclides. The mechanisms of microbial transformations of the major and minor actinides U, Pu, Cm, Am, Np, the fission products and other radionuclides such as Ra, Tc, I, Cs, Sr, under aerobic and anaerobic conditions in the presence of electron donors and acceptors are reviewed.

  12. The time series analysis of the radionuclide emissions from Fukushima Daiichi nuclear power plant by online global chemistry transport model and inverse model

    NASA Astrophysics Data System (ADS)

    Maki, Takashi; Tanaka, Taichu; Kajino, Mizuo; Sekiyama, Tsuyoshi; Igarashi, Yasuhito; Mikami, Masao

    2013-04-01

    The accident of the Fukushima Daiichi nuclear power plant that occurred in March 2011 emitted a large amount of radionuclide. The important feature of this accident was that the source position was evidently clear, however, time and vertical emission variations were unknown (in this case, it was known that the height of emission was not so high in altitude). In such a case, the technique of inverse model was a powerful tool to gain answers to questions; high resolution and more precise analysis by using prior emission information with relatively low computational cost are expected to be obtainable. Tagged simulation results by global aerosol model named MASINGAR (Tanaka et al., 2005) were used; the horizontal resolution was TL319 (about 60 km). Tagged tracers (Cs137) from lowest model layer (surface to 100m) were released every three hours with 1Tg/hr which accumulated daily mean. 50 sites' daily observation data in the world (CTBTO, Ro5, Berkeley, Hoffmann and Taiwan) were collected. The analysis period was 40 days, from 11 March to 19 April. We tested two prior emission information. The first information was JAEA posterior emission (Chino et al., 2011) and the second was NILU prior emission (not posterior) (Stohl et al.,2011) as our observation data were almost similar to their study. Due to consideration for observation error and space representation error, the observation error was set as 20%. Several sensitivity tests were examined by changing prior emission flux uncertainties. As a result, Cs137 estimated the total emission amount from 11 March to 19 April as 18.5PBq with the uncertainty of 3.6PBq. Moreover, the maximum radio nuclei emission occurred during 15 March, which was larger than prior information. The precision of the analysis was highly dependent on observation data (quantity and quality) and precision of transport model. Possibility to obtain robust result by using multi-model ensemble results with inverse model was also considered. The results of

  13. Glucocorticoid affects dendritic transport of BDNF-containing vesicles.

    PubMed

    Adachi, Naoki; Numakawa, Tadahiro; Nakajima, Shingo; Fukuoka, Masashi; Odaka, Haruki; Katanuma, Yusuke; Ooshima, Yoshiko; Hohjoh, Hirohiko; Kunugi, Hiroshi

    2015-08-04

    Brain-derived neurotrophic factor (BDNF) is essential for neuronal survival, differentiation, and functions in the central nervous system (CNS). Because BDNF protein is sorted into secretory vesicles at the trans-Golgi network in the cell body after translation, transport of BDNF-containing vesicles to the secretion sites is an important process for its function. Here we examined the effect of dexamethasone (DEX), a synthetic glucocorticoid, on BDNF-containing vesicle transport and found that DEX decreased the proportion of stationary vesicles and increased velocity of the microtubule-based vesicle transport in dendrites of cortical neurons. Furthermore, DEX increased huntingtin (Htt) protein levels via glucocorticoid receptor (GR) activation, and reduction in the amount of Htt by a specific shRNA reversed the action of DEX on BDNF vesicle transport. Given that Htt protein is a positive regulator for the microtubule-dependent vesicular transport in neurons, our data suggest that glucocorticoid stimulates BDNF vesicle transport through upregulation of Htt protein levels.

  14. Specifications for the development of a fully three-dimensional numerical groundwater model for regional mass transport of radionuclides from a deep waste repository

    SciTech Connect

    Prickett, T.A.

    1980-04-01

    Specifications are given which are necessary to develop a three-dimensional numerical model capable of simulating regional mass transport of radionuclides from a deep waste repository. The model to be developed will include all of the significant mass transport processes including flow, chemical, and thermal advection, mechanical dispersion, molecular diffusion, ion exchange reactions, and radioactive decay. The model specifications also include that density and viscosity fluid properties be functions of pressure, temperature, and concentration and take into account fluid and geologic heterogenieties by allowing possible assignment of individual values to every block of the model. The model specifications furthermore include the repository shape, input/output information, boundary conditions, and the need for documentation and a user's manual. Model code validation can be accomplished with the included known analytical or laboratory solutions. It is recommended that an existing finite-difference model (developed by INTERCOMP and INTERA, Inc.) be used as a starting point either as an acceptable basic code for modification or as a pattern for the development of a completely different numerical scheme. A ten-step plan is given to outline the general procedure for development of the code.

  15. Modeling Radionuclide Decay Chain Migration Using HYDROGEOCHEM

    NASA Astrophysics Data System (ADS)

    Lin, T. C.; Tsai, C. H.; Lai, K. H.; Chen, J. S.

    2014-12-01

    Nuclear technology has been employed for energy production for several decades. Although people receive many benefits from nuclear energy, there are inevitably environmental pollutions as well as human health threats posed by the radioactive materials releases from nuclear waste disposed in geological repositories or accidental releases of radionuclides from nuclear facilities. Theoretical studies have been undertaken to understand the transport of radionuclides in subsurface environments because that the radionuclide transport in groundwater is one of the main pathway in exposure scenarios for the intake of radionuclides. The radionuclide transport in groundwater can be predicted using analytical solution as well as numerical models. In this study, we simulate the transport of the radionuclide decay chain using HYDROGEOCHEM. The simulated results are verified against the analytical solution available in the literature. Excellent agreements between the numerical simulation and the analytical are observed for a wide spectrum of concentration. HYDROGECHEM is a useful tool assessing the ecological and environmental impact of the accidental radionuclide releases such as the Fukushima nuclear disaster where multiple radionuclides leaked through the reactor, subsequently contaminating the local groundwater and ocean seawater in the vicinity of the nuclear plant.

  16. Kinetically influenced terms for solute transport affected by heterogeneous and homogeneous classical reactions

    USGS Publications Warehouse

    Bahr, J.M.

    1990-01-01

    This paper extends a four-step derivation procedure, previously presented for cases of transport affected by surface reactions, to transport problems involving homogeneous reactions. Derivations for these classes of reactions are used to illustrate the manner in which mathematical differences between reaction classes are reflected in the mathematical derivation procedures required to identify kinetically influenced terms. Simulation results for a case of transport affected by a single solution phase complexation reaction and for a case of transport affected by a precipitation-dissolution reaction are used to demonstrate the nature of departures from equilibrium-controlled transport as well as the use of kinetically influenced terms in determining criteria for the applicability of the local equilibrium assumption. A final derivation for a multireaction problem demonstrates the application of the generalized procedure to a case of transport affected by reactions of several classes. -from Author

  17. Radionuclide Retention in Concrete Wasteforms

    SciTech Connect

    Bovaird, Chase C.; Jansik, Danielle P.; Wellman, Dawn M.; Wood, Marcus I.

    2011-09-30

    Assessing long-term performance of Category 3 waste cement grouts for radionuclide encasement requires knowledge of the radionuclide-cement interactions and mechanisms of retention (i.e., sorption or precipitation); the mechanism of contaminant release; the significance of contaminant release pathways; how wasteform performance is affected by the full range of environmental conditions within the disposal facility; the process of wasteform aging under conditions that are representative of processes occurring in response to changing environmental conditions within the disposal facility; the effect of wasteform aging on chemical, physical, and radiological properties; and the associated impact on contaminant release. This knowledge will enable accurate prediction of radionuclide fate when the wasteforms come in contact with groundwater. The information present in the report provides data that (1) measures the effect of concrete wasteform properties likely to influence radionuclide migration; and (2) quantifies the rate of carbonation of concrete materials in a simulated vadose zone repository.

  18. Technology assessment of future intercity passenger transporation systems. Volume 2: Identification of issues affecting intercity transportation

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Papers on major issues and trends that affect the future of intercity transportation are presented. Specific areas covered include: political, social, technological, institutional, and economic mechanisms, the workings of which determine how future intercity transporation technologies will evolve and be put into service; the major issues of intercity transportation from the point of view of reform, including candidate transporation technologies; and technical analysis of trends affecting the evolution of intercity transportation technologies.

  19. Benthic processes affecting contaminant transport in Upper Klamath Lake, Oregon

    USGS Publications Warehouse

    Kuwabara, James S.; Topping, Brent R.; Carter, James L.; Carlson, Rick A; Parchaso, Francis; Fend, Steven V.; Stauffer-Olsen, Natalie; Manning, Andrew J.; Land, Jennie M.

    2016-09-30

    Executive SummaryMultiple sampling trips during calendar years 2013 through 2015 were coordinated to provide measurements of interdependent benthic processes that potentially affect contaminant transport in Upper Klamath Lake (UKL), Oregon. The measurements were motivated by recognition that such internal processes (for example, solute benthic flux, bioturbation and solute efflux by benthic invertebrates, and physical groundwater-surface water interactions) were not integrated into existing management models for UKL. Up until 2013, all of the benthic-flux studies generally had been limited spatially to a number of sites in the northern part of UKL and limited temporally to 2–3 samplings per year. All of the benthic invertebrate studies also had been limited to the northern part of the lake; however, intensive temporal (weekly) studies had previously been completed independent of benthic-flux studies. Therefore, knowledge of both the spatial and temporal variability in benthic flux and benthic invertebrate distributions for the entire lake was lacking. To address these limitations, we completed a lakewide spatial study during 2013 and a coordinated temporal study with weekly sampling of benthic flux and benthic invertebrates during 2014. Field design of the spatially focused study in 2013 involved 21 sites sampled three times as the summer cyanobacterial bloom developed (that is, May 23, June 13, and July 3, 2013). Results of the 27-week, temporally focused study of one site in 2014 were summarized and partitioned into three periods (referred to herein as pre-bloom, bloom and post-bloom periods), each period involving 9 weeks of profiler deployments, water column and benthic sampling. Partitioning of the pre-bloom, bloom, and post-bloom periods were based on water-column chlorophyll concentrations and involved the following date intervals, respectively: April 15 through June 10, June 17 through August 13, and August 20 through October 16, 2014. To examine

  20. Radionuclide distributions and sorption behavior in the Susquehanna--Chesapeake Bay System

    SciTech Connect

    Olsen, C.R.; Larsen, I.L.; Lowry, P.D.; McLean, R.I.; Domotor, S.L.

    1989-01-01

    Radionuclides released into the Susquehanna--Chesapeake System from the Three Mile Island, Peach Bottom, and Calvert Cliffs nuclear power plants are partitioned among dissolved, particulate, and biological phases and may thus exist in a number of physical and chemical forms. In this project, we have measured the dissolved and particulate distributions of fallout /sup 137/Cs; reactor-released /sup 137/Cs, /sup 134/Cs, /sup 65/Zn, /sup 60/Co, and /sup 58/Co; and naturally occurring /sup 7/Be and /sup 210/Pb in the lower Susquehanna River and Upper Chesapeake Bay. In addition, we chemically leached suspended particles and bottom sediments in the laboratory to determine radionuclide partitioning among different particulate-sorbing phases to complement the site-specific field data. This information has been used to document the important geochemical processes that affect the transport, sorption, distribution, and fate of reactor-released radionuclides (and by analogy, other trace contaminants) in this river-estuarine system. Knowledge of the mechanisms, kinetic factors, and processes that affect radionuclide distributions is crucial for predicting their biological availability, toxicity, chemical behavior, physical transport, and accumulation in aquatic systems. The results from this project provide the information necessary for developing accurate radionuclide-transport and biological-uptake models. 76 refs., 12 figs.

  1. Seasonal difference in brain serotonin transporter binding predicts symptom severity in patients with seasonal affective disorder.

    PubMed

    Mc Mahon, Brenda; Andersen, Sofie B; Madsen, Martin K; Hjordt, Liv V; Hageman, Ida; Dam, Henrik; Svarer, Claus; da Cunha-Bang, Sofi; Baaré, William; Madsen, Jacob; Hasholt, Lis; Holst, Klaus; Frokjaer, Vibe G; Knudsen, Gitte M

    2016-05-01

    Cross-sectional neuroimaging studies in non-depressed individuals have demonstrated an inverse relationship between daylight minutes and cerebral serotonin transporter; this relationship is modified by serotonin-transporter-linked polymorphic region short allele carrier status. We here present data from the first longitudinal investigation of seasonal serotonin transporter fluctuations in both patients with seasonal affective disorder and in healthy individuals. Eighty (11)C-DASB positron emission tomography scans were conducted to quantify cerebral serotonin transporter binding; 23 healthy controls with low seasonality scores and 17 patients diagnosed with seasonal affective disorder were scanned in both summer and winter to investigate differences in cerebral serotonin transporter binding across groups and across seasons. The two groups had similar cerebral serotonin transporter binding in the summer but in their symptomatic phase during winter, patients with seasonal affective disorder had higher serotonin transporter than the healthy control subjects (P = 0.01). Compared to the healthy controls, patients with seasonal affective disorder changed their serotonin transporter significantly less between summer and winter (P < 0.001). Further, the change in serotonin transporter was sex- (P = 0.02) and genotype- (P = 0.04) dependent. In the patients with seasonal affective disorder, the seasonal change in serotonin transporter binding was positively associated with change in depressive symptom severity, as indexed by Hamilton Rating Scale for Depression - Seasonal Affective Disorder version scores (P = 0.01). Our findings suggest that the development of depressive symptoms in winter is associated with a failure to downregulate serotonin transporter levels appropriately during exposure to the environmental stress of winter, especially in individuals with high predisposition to affective disorders.media-1vid110.1093/brain/aww043_video_abstractaww043_video_abstract.

  2. Final Report (BMWi Project No.: 02 E 10971): Joint project: Retention of radionuclides relevant for final disposal in natural clay rock and saline systems - Subproject 2: Geochemical behavior and transport of radionuclides in saline systems in the prese

    SciTech Connect

    Schmeide, Katja; Fritsch, Katharina; Lippold, Holger; Poetsch, Maria; Kulenkampff, Johannes; Lippmann-Pipke, Johanna; Jordan, Norbert; Joseph, Claudia; Moll, Henry; Cherkouk, Andrea; Bader, Miriam

    2016-02-29

    The objective of this project was to study the influence of increased salinities on interaction processes in the system radionuclide – organics – clay – aquifer. For this, complexation, redox, sorption, and diffusion studies were performed under variation of the ionic strength (up to 4 mol kg-1) and the background electrolyte (NaCl, CaCl2, MgCl2).

  3. Essays on alternative energy policies affecting the US transportation sector

    NASA Astrophysics Data System (ADS)

    O'Rear, Eric G.

    This dissertation encompasses three essays evaluating the impacts of different policies targeting the greenhouse gas (GHG) emissions, fuel demands, etc. of the transportation sector. Though there are some similarities across the three chapters, each essay stands alone as an independent work. The 2010 US EPA MARKAL model is used in each essay to evaluate policy effects. Essay 1 focuses on the recent increases in Corporate Average Fuel Economy (CAFE) standards, and the implications of a "rebound effect." These increases are compared to a carbon tax generating similar reductions in system-wide emissions. As anticipated, the largest reductions in fuel use by light-duty vehicles (LDV) and emissions are achieved under CAFE. Consideration of the rebound effect does little to distort CAFE benefits. Our work validates many economists' belief that a carbon tax is a more efficient approach. However, because the tax takes advantage of cheaper abatement opportunities in other sectors, reductions in transportation emissions will be much lower than what we observe with CAFE. Essay 2 compares CAFE increases with what some economists suggest would be a much more "efficient" alternative -- a system-wide oil tax internalizing some environmental externalities. Because oil taxes are likely to be implemented in addition to CAFE standards, we consider a combined policy case reflecting this. Our supplementary analysis approximates the appropriate tax rates to produce similar reductions in oil demands as CAFE (CAFE-equivalent tax rates). We discover that taxes result in greater and more cost-effective reductions in system-wide emissions and net oil imports than CAFE. The current fuel tax system is compared to three versions of a national vehicle miles traveled (VMT) tax charged to all LDVs in Essay 3. VMT taxes directly charge motorists for each mile driven and help to correct the problem of eroding tax revenues given the failure of today's fuel taxes to adjust with inflation. Results

  4. [The accumulation of the technogenic radionuclides by mushrooms in the area affected by the activity of the Krasnoyarsk mining-and-chemical industrial complex].

    PubMed

    Bolsunovskiĭ, A Ia; Dement'ev, D V; Bondareva, L G

    2006-01-01

    The radionuclide content was measured in mushrooms collected in different sites situated in the zone of the radiation influence on the Mining-and-Chemical Combine at Zheleznogorsk and on the control site, near Krasnoyarsk, in 2002-2004. The analytical investigations of fruiting bodies of 12 mushroom species have revealed three gamma-emitting radionuclides: 7Be, 40K (natural) and 137Cs (artificial). It was found that only three species contain 7Be; activity concentration of 40K is not species- and site-dependent, averaging 1600 Bq/kg. All collected samples contain 137Cs, and its accumulation by mushrooms is species-specific. Suillus concentrates more 137Cs activity than other species and can be used as a bioindicator of soil contamination with radiocesium. The average activity concentration of 137Cs in Suillus granulatus collected in the sites subjected only to aerosol discharges of the MCC is more than twice higher than 137Cs content of the mushrooms collected in the control site--"Krasnoyarsk". The maximum activity concentration of 137Cs in Suillus samples collected in the sites that receive 137Cs with the flood water is an order of magnitude higher, amounting to 8624 Bq/kg. The analysis of the radionuclide distribution in a mushroom shows that 40K activity concentration is the same in caps and stems of Suillus, and 137Cs concentration in Suillus caps is 1.7-2.3 times higher than in stems. Binding of radionuclides by mushroom biomass was determined by chemical fractionation; it was found that the highest activities of 137Cs and 40K are in the exchange-adsorption fraction (56 to 71% of the total content of a radionuclide) and in the organic fraction (23 to 37%). Calculations were made for determination of the coefficients of 40K and 137Cs transfer from the soil to the fruiting body of Suillus.

  5. Radionuclide Retention in Concrete Wasteforms

    SciTech Connect

    Wellman, Dawn M.; Jansik, Danielle P.; Golovich, Elizabeth C.; Cordova, Elsa A.

    2012-09-24

    Assessing long-term performance of Category 3 waste cement grouts for radionuclide encasement requires knowledge of the radionuclide-cement interactions and mechanisms of retention (i.e., sorption or precipitation); the mechanism of contaminant release; the significance of contaminant release pathways; how wasteform performance is affected by the full range of environmental conditions within the disposal facility; the process of wasteform aging under conditions that are representative of processes occurring in response to changing environmental conditions within the disposal facility; the effect of wasteform aging on chemical, physical, and radiological properties; and the associated impact on contaminant release. This knowledge will enable accurate prediction of radionuclide fate when the wasteforms come in contact with groundwater. Data collected throughout the course of this work will be used to quantify the efficacy of concrete wasteforms, similar to those used in the disposal of LLW and MLLW, for the immobilization of key radionuclides (i.e., uranium, technetium, and iodine). Data collected will also be used to quantify the physical and chemical properties of the concrete affecting radionuclide retention.

  6. BLT-EC (Breach, Leach Transport, and Equilibrium Chemistry), a finite-element model for assessing the release of radionuclides from low-level waste disposal units: Background, theory, and model description

    SciTech Connect

    MacKinnon, R.J.; Sullivan, T.M.; Simonson, S.A.; Suen, C.J.

    1995-08-01

    Performance assessment models typically account for the processes of sorption and dissolution-precipitation by using an empirical distribution coefficient, commonly referred to as K{sub d} that combines the effects of all chemical reactions between solid and aqueous phases. In recent years, however, there has been an increasing awareness that performance assessments based solely on empirically based K{sub d} models may be incomplete, particularly for applications involving radionuclides having sorption and solubility properties that are sensitive to variations in the in-situ chemical environment. To accommodate variations in the in-situ chemical environment, and to assess its impact on radionuclide mobility, it is necessary to model radionuclide release, transport, and chemical processes in a coupled fashion. This modeling has been done and incorporated into the two-dimensional, finite-element, computer code BLT-EC (Breach, Leach, Transport, Equilibrium Chemistry). BLT-EC is capable of predicting container degradation, waste-form leaching, and advective-dispersive, multispecies, solute transport. BLT-EC accounts for retardation directly by modeling the chemical processes of complexation, sorption, dissolution-precipitation, ion-exchange, and oxidation-reduction reactions. In this report we: (1) present a detailed description of the various physical and chemical processes that control the release and migration of radionuclides from shallow land LLW disposal facilities; (2) formulate the mathematical models that represent these processes; (3) outline how these models are incorporated and implemented in BLT-EC; and (4) demonstrate the application of BLT-EC on a set of example problems.

  7. Transuranic radionuclides in the environment surrounding radioactive waste diposal sites, a bibliography

    SciTech Connect

    Stoker, A.C.; Noshkin, V.E.; Wong, K.M.; Brunk, J.L.; Conrado, C.L.; Jones, H.E.; Kehl, S.; Stuart, M.L.; Wasley, L.M.; Bradsher, R.V.

    1994-08-01

    The purpose of this project was to compile a bibliography of references containing environmental transuranic radionuclide data. Our intent was to identify those parameters affecting transuranic radionuclide transport that may be generic and those that may be dependent on chemical form and/or environmental conditions (i.e. site specific). An understanding of the unique characteristics and similarities between source terms and environmental conditions relative to transuranic radionuclide transport and cycling will provide the ability to assess and predict the long term impact on man and the environment. An additional goal of our literature review, was to extract the ranges of environmental transuranic radionuclide data from the identified references for inclusion in a data base. Related to source term, these ranges of data can be used to calculate the dose to man from the radionuclides, and to perform uncertainty analyses on these dose assessments. In an attempt to gather relevant information about the transuranic radionuclides in a variety of environments, we conducted an extensive literature search. In our literature search we identified over 5700 potential written sources of information for review. In addition, we have identified many references which were not found through the literature searches, but which were known to contain useful data. A total of approximately 2600 documents were determined to contain information which would be useful for an in depth study of radionuclides in different environments. The journal articles, books, reports and other documents were reviewed to obtain the source term of the radionuclides studied. Most references containing laboratory study data were not included in our databases. Although these may contain valuable data, we were trying to compile references with information on the behavior of the transuranics in the specific environment being studied.

  8. Mass balances and uncertainty in radionuclide transport at the SRS F-area seepage basins groundwater plume

    NASA Astrophysics Data System (ADS)

    Wiedmer, A.; Hunt, J. R.; Faybishenko, B.; Agarwal, D.; Flach, G. P.; Whiteside, T.; Bennet, P.; Bagwell, L.; Romosan, A.; Hubbard, S. S.

    2011-12-01

    The ability to accurately model and predict flow and reactive transport behavior in soil and groundwater at a radioactively contaminated site is typically constrained by data availability. Techniques for managing, analyzing, and assessing the data are needed. There is a wealth of data and experience to be leveraged from the study of existing DOE sites such as the Savannah River Site (SRS). A new data management system is being developed as part of the Advanced Simulation Capability for Environmental Management (ASCEM) program to allow faster access to data and a more unified framework to address the challenges of site selection and environmental management. The monitoring network of 274 wells surrounding the F-area recorded 350000 data points over a period of almost 60 years. This data management system was developed for data mining, visualization and exploration and was used for F-area groundwater plume mass balance calculations. Process operations at the F-area led to the discharge of more than 12×106 m3 of low-level liquid radioactive waste solutions containing tritium, uranium and fission products into the seepage basins. Between 1953 and 1989, 14 104 Ci (corrected for evaporation and decay to 1989) of tritium was released into the basins according to operational data. Starting in the 1950s, SRS monitored radioactivity in Fourmile Branch (FMB) located downgradient of the basins. Through 1989 a total of 5 104 Ci (decay-corrected to 1989) was detected in FMB, leaving an estimated inventory of 9 104 Ci in the subsurface as of 1989. The sources of uncertainty in the mass balance calculations are discussed and compared with the tritium inventory determined from groundwater monitoring data prior to remediation.

  9. Long-range transport of gaseous 131I and other radionuclides from Fukushima accident to Southern Poland

    NASA Astrophysics Data System (ADS)

    Mietelski, Jerzy W.; Kierepko, Renata; Brudecki, Kamil; Janowski, Paweł; Kleszcz, Krzysztof; Tomankiewicz, Ewa

    2014-07-01

    A serious accident at Fukushima Dai-Ichi NPP triggered radioactive emission to the atmosphere on 12 March 2011. The results of gamma spectrometric measurements of both gaseous and aerosol fraction of the air, collected in Krakow over the period from March 21 till the end of May 2011, as well as wet and dry deposition recorded from March till the end of October 2011, are presented in this paper. Krakow happened to be the first Polish location where radioactive isotopes characteristic for reactor releases, such as 131I, 132I, 129mTe, 132Te, 134Cs, 136Cs, and 137Cs, were detected. The maximum activity for aerosols equal to (5.73 ± 0.35) mBq/m3, (0.461 ± 0.041) mBq/m3 and (0.436 ± 0.038) mBq/m3 for 131I, 134Cs and 137Cs, respectively, was recorded for March 29, 2011. The data on the fallout are also given. The results of the radiochemical analysis of aerosol samples showed no traces of plutonium or americium isotopes associated with the disaster to be detected. The results of air activity concentration from Fukushima accident observed in Central Europe, Poland, in comparison to those of Chernobyl accident observed in Japan are presented and discussed. The comparison has revealed a discrepancy in the recognized relative scale of both accidents, and important difference in long distance transport of contamination, to exist. An attempt to explain the variation in the activity ratios between the aerosol fraction for 131I and 137Cs as resulting from exchange between the gaseous and aerosol fractions of 131I while the contamination had been propagating, is made.

  10. Effect of Clay Nanoparticle Transport, Desorption Kinetics and Redox Equilibrium on Radionuclide Mobility in Fractured Rock investigated at the Grimsel Test Site (Switzerland)

    NASA Astrophysics Data System (ADS)

    Schaefer, T.; Huber, F. M.; Lagos, M.; Quinto, F.; Heck, S.; Martin, A. J.; Blechschmidt, I.; Lanyon, G. W.; Reiche, T.; Noseck, U.

    2015-12-01

    Transport of contaminants in crystalline environments might occur through dissolved species or attached to colloidal or nanoparticulate phases being mobile in water conducting features of the host rock. In this presentation we will discuss the mobility of clay nanoparticles as detected by laser-induced breakdown detection (LIBD) as a function of fracture surface roughness and groundwater chemistry. The on site observed Tc-99, U-233, Np-237, Pu-242 and Am-243 sorption/desorption kinetics with and without natural or synthetic clay minerals (smectites) are compared to laboratory studies under similar groundwater conditions. The desorption or redox kinetics were monitored over a duration of up to 426 days using natural fracture filling material as a concurrence ligand and monitoring the colloid attachment via detection of Al, Si, Ni and Zn as smectite structural elements. For trivalent actinides smectite desorption rates in the range of 1.2-3.7E-3 per hour could be determined and significantly lower desorption rates for tetravalent actinides were found. This results will be compared with field data of migration experiments performed at the Grimsel Test Site (GTS, Switzerland) using the same radionuclides and clay colloidal phases varying the fracture residence time by flow rate adjustment. Furthermore, the long-term actinide mobility will be addressed by presenting AMS/RIMS measurements of (a) samples collected several months into the tailing of the breakthrough curves not any longer detectable by HR-ICP-MS and (b) background samples of different GTS ground waters showing fallout U-236, whereas fallout Pu could not be detected indicating a much lower mobility under the given conditions.

  11. Isotopic ratio and vertical distribution of radionuclides in soil affected by the accident of Fukushima Dai-ichi nuclear power plants.

    PubMed

    Fujiwara, Takeshi; Saito, Takumi; Muroya, Yusa; Sawahata, Hiroyuki; Yamashita, Yuji; Nagasaki, Shinya; Okamoto, Koji; Takahashi, Hiroyuki; Uesaka, Mitsuru; Katsumura, Yosuke; Tanaka, Satoru

    2012-11-01

    The results of γ analyses of soil samples obtained from 50 locations in Fukushima prefecture on April 20, 2011, revealed the presence of a spectrum of radionuclides resulted from the accident of the Fukushima Dai-ichi nuclear power plant (FDNPP). The sum γ radioactivity concentration ranged in more than 3 orders of magnitude, depending on the sampling locations. The contamination of soils in the northwest of the FDNPP was considerable. The (131)I/(137)Cs activity ratios of the soil samples plotted as a function of the distance from the F1 NPPs exhibited three distinctive patterns. Such patterns would reflect not only the different deposition behaviors of these radionuclides, but also on the conditions of associated release events such as temperature and compositions and physicochemical forms of released radionuclides. The (136)Cs/(137)Cs activity ratio, on the other hand, was considered to only reflect the difference in isotopic compositions of source materials. Two locations close to the NPP in the northwest direction were found to be depleted in short-lived (136)Cs. This likely suggested the presence of distinct sources with different (136)Cs/(137)Cs isotopic ratios, although their details were unknown at present. Vertical γ activity profiles of (131)I and (137)Cs were also investigated, using 20-30 cm soil cores in several locations. About 70% or more of the radionuclides were present in the uppermost 2-cm regions. It was found that the profiles of (131)I/(137)Cs activity ratios showed maxima in the 2-4 cm regions, suggesting slightly larger migration of the former nuclide.

  12. Role of transportation in the persuasion process: cognitive and affective responses to antidrug narratives.

    PubMed

    Banerjee, Smita C; Greene, Kathryn

    2012-01-01

    This study examined transportation effects of first- and third-person narratives as well as the role of transportation in the persuasion process. In particular, the authors evaluated the role of transportation in affecting cognitive and affective responses. Last, they addressed the relation between (a) cognitive and affective responses and (b) antidrug expectancies. Participants were 500 undergraduate students at a large northern university in the United Kingdom who were randomly assigned to 1 of 2 conditions: first- or third-person narratives on cocaine use. The results demonstrated that there was no difference between first- and third-person narratives in terms of transportation. However, overall, greater transportation was associated with more favorable cognitive responses, and more favorable cognitive response was associated with stronger anticocaine expectancies. In terms of affective responses, results indicated the mediating role of sadness and contentment in the association between transportation and anticocaine expectancies. In particular, increased transportation was associated with greater sadness and lower contentment. Lower sadness and contentment were associated with stronger anticocaine expectancies. Important theoretical and empirical implications are discussed.

  13. Histidines in potential substrate recognition sites affect thyroid hormone transport by monocarboxylate transporter 8 (MCT8).

    PubMed

    Braun, Doreen; Lelios, Iva; Krause, Gerd; Schweizer, Ulrich

    2013-07-01

    Mutations in monocarboxylate transporter 8 (MCT8; SLC16A2) cause the Allan-Herndon-Dudley syndrome, a severe X-linked psychomotor retardation syndrome. MCT8 belongs to the major facilitator superfamily of 12 transmembrane-spanning proteins and transports thyroid hormones across the blood-brain barrier and into neurons. How MCT8 distinguishes thyroid hormone substrates from structurally closely related compounds is not known. The goal of this study was to identify critical amino acids along the transport channel cavity, which participate in thyroid hormone recognition. The fact that T3 is bound between a His-Arg clamp in the crystal structure of the T3 receptor/T3 complex prompted us to investigate whether such a motif might potentially be relevant for T3 recognition in MCT8. We therefore replaced candidate histidines and arginines by site-directed mutagenesis and performed activity assays in MDCK-1 cells and Xenopus oocytes. Histidines were replaced by alanine, phenylalanine, and glutamine to probe for molecular properties like aromatic ring structure and H-bonding properties. It was found that some mutations in His192 and His415 significantly changed substrate transport kinetics. Arg301 at the intracellular end of the substrate channel is at an ideal distance to His415 to participate in a His-Arg clamp and mutation to alanine-abrogated hormone transport. Molecular modeling demonstrates a perfect fit of T3 poised into the substrate channel between His415 and Arg301 and observing the same geometry as in the T3 receptor.

  14. Natural Radionuclides in Ground Water.

    ERIC Educational Resources Information Center

    Davis, Stanley N.

    1988-01-01

    Described are the natural trace radionuclides in ground water. Indicates the geologic origin of these radionuclides. Discusses the importance of these radionuclides. Suggests future uses of a number of additional radionuclides. (CW)

  15. IMPACTS OF SOLUBILITY AND OTHER GEOCHEMICAL PROCESSES ON RADIONUCLIDE RETARDATION IN THE NATURAL SYSTEM

    SciTech Connect

    B. Arnold

    2005-08-02

    This report documents results and findings of a study of solubility/co-precipitation effects and enhanced sorption due to variations in redox conditions on radionuclide transport in the natural system (BSC 2005 [DIRS 173951]; BSC 2005 [DIRS 173859]) conducted in response to DOE Contracting Officer Authorization Letter 05-001, Item d (Mitchell 2005 [DIRS 173265]). The purpose of this study is to assess the potential impacts of precipitation and enhanced sorption due to variations in redox conditions on radionuclide transport in the saturated zone (SZ) at Yucca Mountain. The information presented in this report is intended to aid in assessing the conservatism in the SZ transport model for supporting the total system performance assessment (TSPA) calculations. A similar study was performed for the impact of solubility/precipitation on radionuclide transport in the unsaturated zone (UZ). However, because the unsaturated zone is under predominantly oxidizing conditions and that the radionuclides released from the engineered barrier system are not expected to precipitate in the UZ for the reasons described below, it was concluded that the effect on unsaturated zone transport is not significant to warrant a detailed study. Solubility limiting conditions for neptunium in the UZ are expected to be similar to the conditions for neptunium solubility in the waste emplacement drift invert, where Np{sub 2}O{sub 5} is recommended as the controlling solid phase (BSC 2005 [DIRS 174566], Section 6.6.1). Solubility limits for neptunium inside the waste package, however, are expected to be controlled by NpO{sub 2} (BSC 2005 [DIRS 174566], Section 6.6.1). The solubility limits for Np2O5 are generally much higher than for NpO{sub 2} (BSC 2005 [DIRS 174566], Tables 6.6-4 and 6.6-7). Therefore, the low concentrations of neptunium releases from waste packages are unlikely to be affected by solubility limits in the unsaturated zone. The SZ is part of the Lower Natural Barrier to the

  16. Transport and sorting of the solanum tuberosum sucrose transporter SUT1 is affected by posttranslational modification.

    PubMed

    Krügel, Undine; Veenhoff, Liesbeth M; Langbein, Jennifer; Wiederhold, Elena; Liesche, Johannes; Friedrich, Thomas; Grimm, Bernhard; Martinoia, Enrico; Poolman, Bert; Kühn, Christina

    2008-09-01

    The plant sucrose transporter SUT1 from Solanum tuberosum revealed a dramatic redox-dependent increase in sucrose transport activity when heterologously expressed in Saccharomyces cerevisiae. Plant plasma membrane vesicles do not show any change in proton flux across the plasma membrane in the presence of redox reagents, indicating a SUT1-specific effect of redox reagents. Redox-dependent sucrose transport activity was confirmed electrophysiologically in Xenopus laevis oocytes with SUT1 from maize (Zea mays). Localization studies of green fluorescent protein fusion constructs showed that an oxidative environment increased the targeting of SUT1 to the plasma membrane where the protein concentrates in 200- to 300-nm raft-like microdomains. Using plant plasma membranes, St SUT1 can be detected in the detergent-resistant membrane fraction. Importantly, in yeast and in plants, oxidative reagents induced a shift in the monomer to dimer equilibrium of the St SUT1 protein and increased the fraction of dimer. Biochemical methods confirmed the capacity of SUT1 to form a dimer in plants and yeast cells in a redox-dependent manner. Blue native PAGE, chemical cross-linking, and immunoprecipitation, as well as the analysis of transgenic plants with reduced expression of St SUT1, confirmed the dimerization of St SUT1 and Sl SUT1 (from Solanum lycopersicum) in planta. The ability to form homodimers in plant cells was analyzed by the split yellow fluorescent protein technique in transiently transformed tobacco (Nicotiana tabacum) leaves and protoplasts. Oligomerization seems to be cell type specific since under native-like conditions, a phloem-specific reduction of the dimeric form of the St SUT1 protein was detectable in SUT1 antisense plants, whereas constitutively inhibited antisense plants showed reduction only of the monomeric form. The role of redox control of sucrose transport in plants is discussed.

  17. Radionuclide deposition control

    DOEpatents

    Brehm, William F.; McGuire, Joseph C.

    1980-01-01

    The deposition of radionuclides manganese-54, cobalt-58 and cobalt-60 from liquid sodium coolant is controlled by providing surfaces of nickel or high nickel alloys to extract the radionuclides from the liquid sodium, and by providing surfaces of tungsten, molybdenum or tantalum to prevent or retard radionuclide deposition.

  18. Potential influence of organic compounds on the transport of radionuclides from a geologic repository. Assessment of effectiveness of geologic isolation systems

    SciTech Connect

    Silviera, D.J.

    1981-03-01

    This study identifies organic compounds that may be present in a repository and outlines plausible interactions and mechanisms that may influence the forms and chemical behavior of these compounds. A review of the literature indicates that large quantities of organic radioactive wastes are generated by the nuclear industry and if placed in a repository could increase or decrease the leach rate and sorption characteristics of waste radionuclides. The association of radionuclides with organic matter can render the nuclides soluble or insoluble depending on the particular nuclide and such parameters as the pH, Eh, and temperature of the hydrogeologic system as well as the properties of the organic compounds themselves. 44 references.

  19. Regulatory Technology Development Plan - Sodium Fast Reactor. Mechanistic Source Term - Metal Fuel Radionuclide Release

    SciTech Connect

    Grabaskas, David; Bucknor, Matthew; Jerden, James

    2016-02-01

    The development of an accurate and defensible mechanistic source term will be vital for the future licensing efforts of metal fuel, pool-type sodium fast reactors. To assist in the creation of a comprehensive mechanistic source term, the current effort sought to estimate the release fraction of radionuclides from metal fuel pins to the primary sodium coolant during fuel pin failures at a variety of temperature conditions. These release estimates were based on the findings of an extensive literature search, which reviewed past experimentation and reactor fuel damage accidents. Data sources for each radionuclide of interest were reviewed to establish release fractions, along with possible release dependencies, and the corresponding uncertainty levels. Although the current knowledge base is substantial, and radionuclide release fractions were established for the elements deemed important for the determination of offsite consequences following a reactor accident, gaps were found pertaining to several radionuclides. First, there is uncertainty regarding the transport behavior of several radionuclides (iodine, barium, strontium, tellurium, and europium) during metal fuel irradiation to high burnup levels. The migration of these radionuclides within the fuel matrix and bond sodium region can greatly affect their release during pin failure incidents. Post-irradiation examination of existing high burnup metal fuel can likely resolve this knowledge gap. Second, data regarding the radionuclide release from molten high burnup metal fuel in sodium is sparse, which makes the assessment of radionuclide release from fuel melting accidents at high fuel burnup levels difficult. This gap could be addressed through fuel melting experimentation with samples from the existing high burnup metal fuel inventory.

  20. Facilities, breed and experience affect ease of sheep handling: the livestock transporter's perspective.

    PubMed

    Burnard, C L; Pitchford, W S; Hocking Edwards, J E; Hazel, S J

    2015-08-01

    An understanding of the perceived importance of a variety of factors affecting the ease of handling of sheep and the interactions between these factors is valuable in improving profitability and welfare of the livestock. Many factors may contribute to animal behaviour during handling, and traditionally these factors have been assessed in isolation under experimental conditions. A human social component to this phenomenon also exists. The aim of this study was to gain a deeper understanding of the importance of a variety of factors affecting ease of handling, and the interactions between these from the perspective of the livestock transporter. Qualitative interviews were used to investigate the factors affecting sheep behaviour during handling. Interview transcripts underwent thematic analysis. Livestock transporters discussed the effects of attitudes and behaviours towards sheep, helpers, facilities, distractions, environment, dogs and a variety of sheep factors including breed, preparation, experience and sex on sheep behaviour during handling. Transporters demonstrated care and empathy and stated that patience and experience were key factors determining how a person might deal with difficult sheep. Livestock transporters strongly believed facilities (ramps and yards) had the greatest impact, followed by sheep experience (naivety of the sheep to handling and transport) and breed. Transporters also discussed the effects of distractions, time of day, weather, dogs, other people, sheep preparation, body condition and sheep sex on ease of handling. The concept of individual sheep temperament was indirectly expressed.

  1. Coupling of hydrologic transport and chemical reactions in a stream affected by acid mine drainage

    USGS Publications Warehouse

    Kimball, B.A.; Broshears, R.E.; Bencala, K.E.; McKnight, Diane M.

    1994-01-01

    Experiments in St. Kevin Gulch, an acid mine drainage stream, examined the coupling of hydrologic transport to chemical reactions affecting metal concentrations. Injection of LiCl as a conservative tracer was used to determine discharge and residence time along a 1497-m reach. Transport of metals downstream from inflows of acidic, metal-rich water was evaluated based on synoptic samples of metal concentrations and the hydrologic characteristics of the stream. Transport of SO4 and Mn was generally conservative, but in the subreaches most affected by acidic inflows, transport was reactive. Both 0.1-??m filtered and particulate Fe were reactive over most of the stream reach. Filtered Al partitioned to the particulate phase in response to high instream concentrations. Simulations that accounted for the removal of SO4, Mn, Fe, and Al with first-order reactions reproduced the steady-state profiles. The calculated rate constants for net removal used in the simulations embody several processes that occur on a stream-reach scale. The comparison between rates of hydrologie transport and chemical reactions indicates that reactions are only important over short distances in the stream near the acidic inflows, where reactions occur on a comparable time scale with hydrologic transport and thus affect metal concentrations.

  2. Accumulation of radionuclides in selected marine biota from Manjung coastal area

    NASA Astrophysics Data System (ADS)

    Abdullah, Anisa; Hamzah, Zaini; Saat, Ahmad; Wood, Ab. Khalik; Alias, Masitah

    2015-04-01

    Distribution of radionuclides from anthropogenic activities has been intensively studied due to the accumulation of radionuclides in marine ecosystem. Manjung area is affected by rapid population growth and socio-economic development such as heavy industrial activities including coal fired power plant, iron foundries, port development and factories, agricultural runoff, waste and toxic discharge from factories.It has radiological risk and toxic effect when effluent from the industries in the area containing radioactive materials either being transported to the atmosphere and deposited back over the land or by run off to the river and flow into coastal area and being absorbed by marine biota. Radionuclides presence in the marine ecosystem can be adversely affect human health when it enters the food chain. This study is focusing on the radionuclides [thorium (Th), uranium (U), radium-226 (226Ra), radium-228 (228Ra) and potassium-40 (40K)] content in marine biota and sea water from Manjung coastal area. Five species of marine biota including Johnius dussumieri (Ikan Gelama), Pseudorhombus malayanus (Ikan Sebelah), Arius maculatus (Ikan Duri), Portunus pelagicus (Ketam Renjong) and Charybdis natator (Ketam Salib) were collected during rainy and dry seasons. Measurements were carried out using Inductively Coupled Plasma Mass Spectrometer (ICPMS). The results show that the concentration of radionuclides varies depends on ecological environment of respective marine biota species. The concentrations and activity concentrations are used for the assessment of potential internal hazard index (Hin), transfer factor (TF), ingestion dose rate (D) and health risk index (HRI) to monitor radiological risk for human consumption.

  3. Characterization of calculation of in-situ retardation factors of contaminant transport using naturally-radionuclides and rock/water interaction occurring U-Series disequilibria timescales. 1997 annual progress report

    SciTech Connect

    Roback, R.; Murrel, M.; Goldstein, S.; Ku, T.L.; Luo, S.

    1997-01-01

    'The research is directed toward a quantitative assessment of contaminant transport rates in fracture-rock systems using uranium-series radionuclides. Naturally occurring uranium-and thorium-series radioactive disequilibria will provide information on the rates of adsorption-desorption and transport of radioactive contaminants as well as on fluid transport and rock dissolution in a natural setting. This study will also provide an improved characterization of preferential flow and contaminant transport at the Idaho Environmental and Engineering Lab. (INEEL) site. To a lesser extent, the study will include rocks in the unsaturated zone. The authors will produce a realistic model of radionuclide migration under unsaturated and saturated field conditions at the INEEL site, taking into account the retardation processes involved in the rock/water interaction. The major tasks are to (1) determine the natural distribution of U, Th, Pa and Ra isotopes in rock minerals. sorbed phases on the rocks, and in fluids from both saturated and unsaturated zones at the site, and (2) study rock/water interaction processes using U/Th series disequilibrium and a statistical analysis-based model for the Geologic heterogeneity plays an important role in transporting contaminants in fractured rocks. Preferential flow paths in the fractured rocks act as a major pathway for transport of radioactive contaminants in groundwaters. The weathering/dissolution of rock by groundwater also influences contaminant mobility. Thus, it is important to understand the hydrogeologic features of the site and their impact on the migration of radioactive contaminants. In this regard, quantification of the rock weathering/dissolution rate and fluid residence time from the observed decay-series disequilibria will be valuable. By mapping the spatial distribution of the residence time of groundwater in fractured rocks, the subsurface preferential flow paths (with high rock permeability and short fluid residence

  4. Membrane transporters and protein traffic networks differentially affecting metal tolerance: a genomic phenotyping study in yeast

    PubMed Central

    Ruotolo, Roberta; Marchini, Gessica; Ottonello, Simone

    2008-01-01

    Background The cellular mechanisms that underlie metal toxicity and detoxification are rather variegated and incompletely understood. Genomic phenotyping was used to assess the roles played by all nonessential Saccharomyces cerevisiae proteins in modulating cell viability after exposure to cadmium, nickel, and other metals. Results A number of novel genes and pathways that affect multimetal as well as metal-specific tolerance were discovered. Although the vacuole emerged as a major hot spot for metal detoxification, we also identified a number of pathways that play a more general, less direct role in promoting cell survival under stress conditions (for example, mRNA decay, nucleocytoplasmic transport, and iron acquisition) as well as proteins that are more proximally related to metal damage prevention or repair. Most prominent among the latter are various nutrient transporters previously not associated with metal toxicity. A strikingly differential effect was observed for a large set of deletions, the majority of which centered on the ESCRT (endosomal sorting complexes required for transport) and retromer complexes, which - by affecting transporter downregulation and intracellular protein traffic - cause cadmium sensitivity but nickel resistance. Conclusion The data show that a previously underestimated variety of pathways are involved in cadmium and nickel tolerance in eukaryotic cells. As revealed by comparison with five additional metals, there is a good correlation between the chemical properties and the cellular toxicity signatures of various metals. However, many conserved pathways centered on membrane transporters and protein traffic affect cell viability with a surprisingly high degree of metal specificity. PMID:18394190

  5. Oocyte aging-induced Neuronatin (NNAT) hypermethylation affects oocyte quality by impairing glucose transport in porcine

    PubMed Central

    Gao, Ying-Ying; Chen, Li; Wang, Tao; Nie, Zheng-Wen; Zhang, Xia; Miao, Yi-Liang

    2016-01-01

    DNA methylation plays important roles in regulating many physiological behaviors; however, few studies were focused on the changes of DNA methylation during oocyte aging. Early studies showed that some imprinted genes’ DNA methylation had been changed in aged mouse oocytes. In this study, we used porcine oocytes to test the hypothesis that oocyte aging would alter DNA methylation pattern of genes and disturb their expression in age oocytes, which affected the developmental potential of oocytes. We compared several different types of genes and found that the expression and DNA methylation of Neuronatin (NNAT) were disturbed in aged oocytes significantly. Additional experiments demonstrated that glucose transport was impaired in aged oocytes and injection of NNAT antibody into fresh oocytes led to the same effects on glucose transport. These results suggest that the expression of NNAT was declined by elevating DNA methylation, which affected oocyte quality by decreasing the ability of glucose transport in aged oocytes. PMID:27782163

  6. Connexin-deficiency affects expression levels of glial glutamate transporters within the cerebrum.

    PubMed

    Unger, Tina; Bette, Stefanie; Zhang, Jiong; Theis, Martin; Engele, Jürgen

    2012-01-06

    The glial glutamate transporter subtypes, GLT-1/EAAT-2 and GLAST/EAAT-1 clear the bulk of extracellular glutamate and are severely dysregulated in various acute and chronic brain diseases. Despite the previous identification of several extracellular factors modulating glial glutamate transporter expression, our knowledge of the regulatory network controlling glial glutamate transport in health and disease still remains incomplete. In studies with cultured cortical astrocytes, we previously obtained evidence that glial glutamate transporter expression is also affected by gap junctions/connexins. To assess whether gap junctions would likewise control the in vivo expression of glial glutamate transporters, we have now assessed their expression levels in brains of conditional Cx43 knockout mice, total Cx30 knockouts, as well as Cx43/Cx30 double knockouts. We found that either knocking out Cx30, Cx43, or both increases GLT-1/EAAT-2 protein levels in the cerebral cortex to a similar extent. By contrast, GLAST/EAAT-1 protein levels maximally increased in cerebral cortices of Cx30/Cx43 double knockouts, implying that gap junctions differentially affect the expression of GLT-1/EAAT-2 and GLAST/EAAT-1. Quantitative PCR analysis further revealed that increases in glial glutamate transporter expression are brought about by transcriptional and translational/posttranslational processes. Moreover, GLT-1/EAAT-2- and GLAST/EAAT-1 protein levels remained unchanged in the hippocampi of Cx43/Cx30 double knockouts when compared to Cx43fl/fl controls, indicating brain region-specific effects of gap junctions on glial glutamate transport. Since astrocytic gap junction coupling is affected in various forms of brain injuries, our findings point to gap junctions/connexins as important regulators of glial glutamate turnover in the diseased cerebral cortex.

  7. DIRECT COMPARISON OF KINETIC AND LOCAL EQUILIBRIUM FORMULATIONS FOR SOLUTE TRANSPORT AFFECTED BY SURFACE REACTIONS.

    USGS Publications Warehouse

    Bahr, Jean M.; Rubin, Jacob

    1987-01-01

    Modeling transport of reacting solutes in porous media often requires a choice between models based on the local equilibrium assumption (LEA) and models involving reaction kinetics. Direct comparison of the mathematical formulations for these two types of transport models can aid in this choice. For cases of transport affected by surface reaction, such a comparison is made possible by a new derivation procedure. This procedure yields a kinetics-based formulation that is the sum of the LEA formulation and one or more kinetically influenced terms. The dimensionless form of the new kinetics-based formulation facilitates identification of critical parameter groupings which control the approach to transport behavior consistent with LEA model predictions. Results of numerical experiments demonstrate that criteria for LEA applicability can be expressed conveniently in terms of these parameter groupings. The derivation procedure is demonstrated for examples of surface reactions including first-order reversible sorption, Langmuir-type kinetics and binary, homovalent ion exchange.

  8. [Vertical transporting risk of nitrogen in purple soil affected by surfactant].

    PubMed

    Chen, Yu-cheng; Yang, Zhi-min; Jiang, Ling; Chen, Qing-hu; Gao, Meng

    2010-07-01

    The simulated leaching experiment was conducted to determine the effects of surfactant of sodium dodecyl benzene sulphonate (SDBS) on vertical transporting of nitrogen in purple soil. SDBS could reduce NH4+ -N loss from soil, and the higher concentration of SDBS, the less loss. SDBS could increase NO3- -N loss from soil, and the order of accumulation loss is SDBS100 > SDBS40 > SDBS0 > SDBS5. Lower concentration SDBS decrease TKN loss, but higher concentration SDBS had a reverse effect, and compared with SDBS0, the accumulation loss TKN of SDBS40, SDBS100 increased by 16.8%, 22.36%, respectively. SDBS could affect vertical transporting of nitrogen in purple soil, that is, the significant down-transporting of nitrogen was observed after leaching with SDBS, and the higher concentration of SDBS, the more obviously transporting trend.

  9. Importance of colloids in the transport within the dissolved phase (<450 nm) of artificial radionuclides from the Rhône river towards the Gulf of Lions (Mediterranean Sea).

    PubMed

    Eyrolle, Frédérique; Charmasson, Sabine

    2004-01-01

    The significance of colloidal fractions regarding the transport of artificial radionuclides in natural water systems is underlined by using sequential ultrafiltration both in the Rhône freshwater and the marine area under and outside the influence of the river outflow. Indeed, the Rhodanian aquatic system represents an interesting test site as various artificial radionuclides are released into the Rhône river by several nuclear installations. We focused our study on (137)Cs, (106)Ru, (60)Co, (238)Pu and (239+240)Pu. Our results show that Fe, Al and Organic carbon (OC) are the main components of colloidal matter. Colloids represent about 15% of dissolved (<450 nm) OC and 25% of dissolved Fe and Al exported towards the sea. Within the dissolved (< 450 nm) phase, these colloidal compounds are shown to account for the transport of 40% for both Co and Ru, 60% for (238)Pu and (239+240)Pu and have no significance on (137)Cs flux.

  10. Decreased vesicular monoamine transporter 2 (VMAT2) and dopamine transporter (DAT) function in knockout mice affects aging of dopaminergic systems

    PubMed Central

    Hall, F. S.; Itokawa, K.; Schmitt, A.; Moessner, R.; Sora, I.; Lesch, K. P.; Uhl, G. R.

    2013-01-01

    Dopamine (DA) is accumulated and compartmentalized by the dopamine transporter (DAT; SLC3A6) and the vesicular monoamine transporter 2 (VMAT2; SLC18A2). These transporters work at the plasma and vesicular membranes of dopaminergic neurons, respectively, and thus regulate levels of DA in neuronal compartments that include the extravesicular cytoplasmic compartment. DA in this compartment has been hypothesized to contribute to oxidative damage that can reduce the function of dopaminergic neurons in aging brains and may contribute to reductions in dopaminergic neurochemical markers, locomotor behavior and responses to dopaminergic drugs that are found in aged animals. The studies reported here examined aged mice with heterozygous deletions of VMAT2 or of DAT, which each reduce transporter expression to about 50% of levels found in wild-type (WT) mice. Aged mice displayed reduced locomotor responses under a variety of circumstances, including in response to locomotor stimulants, as well as changes in monoamine levels and metabolites in a regionally dependent manner. Several effects of aging were more pronounced in heterozygous VMAT2 knockout (KO) mice, including aging induced reductions in locomotion and reduced locomotor responses to cocaine. By contrast, some effects of aging were reduced or not observed in heterozygous DAT KO mice. These findings support the idea that altered DAT and VMAT2 expression affect age-related changes in dopaminergic function. These effects are most likely mediated by alterations in DA compartmentalization, and might be hypothesized to be more exacerbated by other factors that affect the metabolism of cytosolic DA. PMID:23978383

  11. Radionuclide bone imaging and densitometry

    SciTech Connect

    Mettler, F.A.

    1988-01-01

    This book contains 13 selections. Some of the titles are: Radionuclides and the Normal Bone Scan; The Radionuclide Bone Scan in Malignant Disease; Pediatric Applications of Radionuclide Bone Imaging; The Radionuclide Bone Scan in Arthritis and Metabolic and Miscellaneous Disorders; and Soft Tissue Activity on the Radionuclide Bone Scan.

  12. Biogeochemical cycles of Chernobyl-born radionuclides in the contaminated forest ecosystems: long-term dynamics of the migration processes

    NASA Astrophysics Data System (ADS)

    Shcheglov, Alexey; Tsvetnova, Ol'ga; Klyashtorin, Alexey

    2013-04-01

    Biogeochemical migration is a dominant factor of the radionuclide transport through the biosphere. In the early XX century, V.I. Vernadskii, a Russian scientist known, noted about a special role living things play in transport and accumulation of natural radionuclide in various environments. The role of biogeochemical processes in migration and redistribution of technogenic radionuclides is not less important. In Russia, V. M. Klechkovskii and N.V. Timofeev-Ressovskii showed some important biogeochemical aspects of radionuclide migration by the example of global fallout and Kyshtym accident. Their followers, R.M. Alexakhin, M.A. Naryshkin, N.V. Kulikov, F.A. Tikhomirov, E.B. Tyuryukanova, and others also contributed a lot to biogeochemistry of radionuclides. In the post-Chernobyl period, this area of knowledge received a lot of data that allowed building the radioactive element balance and flux estimation in various biogeochemical cycles [Shcheglov et al., 1999]. Regrettably, many of recent radioecological studies are only focused on specific radionuclide fluxes or pursue some applied tasks, missing the holistic approach. Most of the studies consider biogeochemical fluxes of radioactive isotopes in terms of either dose estimation or radionuclide migration rates in various food chains. However, to get a comprehensive picture and develop a reliable forecast of environmental, ecological, and social consequences of radioactive pollution in a vast contaminated area, it is necessary to investigate all the radionuclide fluxes associated with the biogeochemical cycles in affected ecosystems. We believe such an integrated approach would be useful to study long-term environmental consequences of the Fukushima accident as well. In our long-term research, we tried to characterize the flux dynamics of the Chernobyl-born radionuclides in the contaminated forest ecosystems and landscapes as a part of the integrated biogeochemical process. Our field studies were started in June of

  13. Distribution and transport of radionuclides in a boreal mire--assessing past, present and future accumulation of uranium, thorium and radium.

    PubMed

    Lidman, Fredrik; Ramebäck, Henrik; Bengtsson, Åsa; Laudon, Hjalmar

    2013-07-01

    The spatial distribution of (238)U, (226)Ra, (40)K and the daughters of (232)Th, (228)Ra and (228)Th, were measured in a small mire in northern Sweden. High activity concentrations of (238)U and (232)Th (up to 41 Bq (238)U kg(-1)) were observed in parts of the mire with a historical or current inflow of groundwater from the surrounding till soils, but the activities declined rapidly further out in the mire. Near the outlet and in the central parts of the mire the activity concentrations were low, indicating that uranium and thorium are immobilized rapidly upon their entering the peat. The (226)Ra was found to be more mobile with high activity concentrations further out into the mire (up to 24 Bq kg(-1)), although the central parts and the area near the outlet of the mire still had low activity concentrations. Based on the fluxes to and from the mire, it was estimated that approximately 60-70% of the uranium and thorium entering the mire currently is retained within it. The current accumulation rates were found to be consistent with the historical accumulation, but possibly lower. Since much of the accumulation still is concentrated to the edges of the mire and the activities are low compared to other measurements of these radionuclides in peat, there are no indications that the mire will be saturated with respect to radionuclides like uranium, thorium and radium in the foreseen future. On the contrary, normal peat growth rates for the region suggest that the average activity concentrations of the peat currently may be decreasing, since peat growth may be faster than the accumulation of radionuclides. In order to assess the total potential for accumulation of radionuclides more thoroughly it would, however, be necessary to also investigate the behaviour of other organophilic elements like aluminium, which are likely to compete for binding sites on the organic material. Measurements of the redox potential and other redox indicators demonstrate that uranium possibly

  14. Psychostimulants affect dopamine transmission through both dopamine transporter-dependent and independent mechanisms.

    PubMed

    dela Peña, Ike; Gevorkiana, Ruzanna; Shi, Wei-Xing

    2015-10-05

    The precise mechanisms by which cocaine and amphetamine-like psychostimulants exert their reinforcing effects are not yet fully defined. It is widely believed, however, that these drugs produce their effects by enhancing dopamine neurotransmission in the brain, especially in limbic areas such as the nucleus accumbens, by inducing dopamine transporter-mediated reverse transport and/or blocking dopamine reuptake though the dopamine transporter. Here, we present the evidence that aside from dopamine transporter, non-dopamine transporter-mediated mechanisms also participate in psychostimulant-induced dopamine release and contribute to the behavioral effects of these drugs, such as locomotor activation and reward. Accordingly, psychostimulants could increase norepinephrine release in the prefrontal cortex, the latter then alters the firing pattern of dopamine neurons resulting in changes in action potential-dependent dopamine release. These alterations would further affect the temporal pattern of dopamine release in the nucleus accumbens, thereby modifying information processing in that area. Hence, a synaptic input to a nucleus accumbens neuron may be enhanced or inhibited by dopamine depending on its temporal relationship to dopamine release. Specific temporal patterns of dopamine release may also be required for certain forms of synaptic plasticity in the nucleus accumbens. Together, these effects induced by psychostimulants, mediated through a non-dopamine transporter-mediated mechanism involving norepinephrine and the prefrontal cortex, may also contribute importantly to the reinforcing properties of these drugs.

  15. Probabilities of adverse weather affecting transport in Europe: climatology and scenarios up to the 2050s

    NASA Astrophysics Data System (ADS)

    Vajda, A.; Tuomenvirta, H.; Jokinen, P.; Luomaranta, A.; Makkonen, L.; Tikanmäki, M.; Groenemeijer, P.; Saarikivi, P.; Michaelides, S.; Papadakis, M.; Tymvios, F.; Athanasatos, S.

    2012-04-01

    This paper provides the first comprehensive climatology of the adverse and extreme weather events affecting the European transport system by estimating the frequency (or probability) of phenomena for the present climate (1971-2000) and an overview of the projected changes in some of these extremes in the future climate until the 2050s. The research was carried out within the framework of the EWENT Project that addresses the European Union (EU) policies and strategies related to climate change, with a particular focus on extreme weather impacts on the EU transportation system. This project is funded by the Seventh Framework Programme (Transports, call ID FPT7-TPT-2008-RTD-1). The analyzed phenomena are wind, snow, blizzards, heavy precipitation, cold spells and heat waves. In addition, reduced visibility conditions determined by fog and dust events, small-scale phenomena affecting the transport system, such as thunderstorms, lightning, large hail and tornadoes and events damaging infrastructure of the transport system, have been considered. Frequency and probability analysis of past and present ex¬tremes were performed using observational and atmospheric reanalysis data. Future changes in the probability of severe events were assessed based on six regional climate model simulations produced in the FP6 ENSEMBLES project (http://www.ensembles-eu.org/). To facilitate the assessment of impacts and consequences of extreme phenomena on a continental level, the WP2 Deliverable introduces a regionalization of the European extreme phenomena, defining the climate zones with similarities in extreme phenomena. The projected changes as well as large natural variability in weather extremes on the transportation network will have impacts of both signs. The decline of extreme cold and snowfall over most of the continent implies a positive impact on road, rail, inland water and air transportation, e.g., by reducing snow removal. However, even with a general decreasing trend in

  16. Review of the transport of selected radionuclides in the interim risk assessment for the Radioactive Waste Management Complex, Waste Area Group 7 Operable Unit 7-13/14, Idaho National Engineering and Environmental Laboratory, Idaho

    USGS Publications Warehouse

    Rousseau, Joseph P.; Landa, Edward R.; Nimmo, John R.; Cecil, L. DeWayne; Knobel, LeRoy L.; Glynn, Pierre D.; Kwicklis, Edward M.; Curtis, Gary P.; Stollenwerk, Kenneth G.; Anderson, Steven R.; Bartholomay, Roy C.; Bossong, Clifford R.; Orr, Brennon R.

    2005-01-01

    The U.S. Department of Energy (DOE) requested that the U.S. Geological Survey conduct an independent technical review of the Interim Risk Assessment (IRA) and Contaminant Screening for the Waste Area Group 7 (WAG-7) Remedial Investigation, the draft Addendum to the Work Plan for Operable Unit 7-13/14 WAG-7 comprehensive Remedial Investigation and Feasibility Study (RI/FS), and supporting documents that were prepared by Lockheed Martin Idaho Technologies, Inc. The purpose of the technical review was to assess the data and geotechnical approaches that were used to estimate future risks associated with the release of the actinides americium, uranium, neptunium, and plutonium to the Snake River Plain aquifer from wastes buried in pits and trenches at the Subsurface Disposal Area (SDA). The SDA is located at the Radioactive Waste Management Complex in southeastern Idaho within the boundaries of the Idaho National Engineering and Environmental Laboratory. Radionuclides have been buried in pits and trenches at the SDA since 1957 and 1952, respectively. Burial of transuranic wastes was discontinued in 1982. The five specific tasks associated with this review were defined in a ?Proposed Scope of Work? prepared by the DOE, and a follow-up workshop held in June 1998. The specific tasks were (1) to review the radionuclide sampling data to determine how reliable and significant are the reported radionuclide detections and how reliable is the ongoing sampling program, (2) to assess the physical and chemical processes that logically can be invoked to explain true detections, (3) to determine if distribution coefficients that were used in the IRA are reliable and if they have been applied properly, (4) to determine if transport model predictions are technically sound, and (5) to identify issues needing resolution to determine technical adequacy of the risk assessment analysis, and what additional work is required to resolve those issues.

  17. Soil water repellency affects production and transport of CO2 and CH4 in soil

    NASA Astrophysics Data System (ADS)

    Urbanek, Emilia; Qassem, Khalid

    2016-04-01

    Soil moisture is known to be vital in controlling both the production and transport of C gases in soil. Water availability regulates the decomposition rates of soil organic matter by the microorganisms, while the proportion of water/air filled pores controls the transport of gases within the soil and at the soil-atmosphere interface. Many experimental studies and process models looking at soil C gas fluxes assume that soil water is uniformly distributed and soil is easily wettable. Most soils, however, exhibit some degree of soil water repellency (i.e. hydrophobicity) and do not wet spontaneously when dry or moderately moist. They have restricted infiltration and conductivity of water, which also results in extremely heterogeneous soil water distribution. This is a world-wide occurring phenomenon which is particularly common under permanent vegetation e.g. forest, grass and shrub vegetation. This study investigates the effect of soil water repellency on microbial respiration, CO2 transport within the soil and C gas fluxes between the soil and the atmosphere. The results from the field monitoring and laboratory experiments show that soil water repellency results in non-uniform water distribution in the soil which affects the CO2 and CH4 gas fluxes. The main conclusion from the study is that water repellency not only affects the water relations in the soil, but has also a great impact on greenhouse gas production and transport and therefore should be included as an important parameter during the sites monitoring and modelling of gas fluxes.

  18. A methodology for the assessment of rehabilitation success of post mining landscapes--sediment and radionuclide transport at the former Nabarlek uranium mine, Northern Territory, Australia.

    PubMed

    Hancock, G R; Grabham, M K; Martin, P; Evans, K G; Bollhöfer, A

    2006-02-01

    Protection of the environment post-mining is an important issue, especially where runoff and erosion can lead to undesirable material leaving post-mining landscapes and contaminating surrounding land and watercourses. Methods for assessment of the environmental impact and long-term behaviour of post-mining landforms based on scientific methodology are needed especially where field data are absent or poor. An appraisal of the former Nabarlek uranium mine was conducted to assess the site from a soil erosion perspective as part of an independent evaluation of overall rehabilitation success. Determination of the gross erosion occurring, sediment discharge to Cooper Creek and the resultant sediment associated radionuclide load in Cooper Creek were the primary objectives of the study. These objectives were achieved through the application of several models using parameter values collected from the site. The study found that the area containing the mill tailings repository is extremely stable and meets the guidelines established for long-term storage of uranium mill tailings. Most other areas on the site are stable; however there are some areas with a high sediment loss. Sediment concentration in Cooper Creek, which drains the site, was found to be within the Australian water quality guidelines for fresh water, however sediment concentrations in tributaries were found to exceed recommended levels. Radionuclide determinations on soil samples showed that the highest specific activities (Bq kg-1) were present on a small (0.44 ha) area with a relatively high erosion rate. This small area contributed the majority of the estimated flux to Cooper Creek of uranium-series radionuclides sorbed or structurally incorporated to eroded soil particles sourced from the mine site. This study provides a methodology for assessment of the erosional stability of such a landscape and consequent impact on water quality, using extensive field data and readily available and well known models and

  19. Factors affecting body weight loss during commercial long haul transport of cattle in North America.

    PubMed

    González, L A; Schwartzkopf-Genswein, K S; Bryan, M; Silasi, R; Brown, F

    2012-10-01

    The objective of the present study was to identify and quantify several factors affecting shrink in cattle during commercial long-haul transport (≥400 km; n = 6,152 journeys). Surveys were designed and delivered to transport carriers to collect relevant information regarding the characteristics of animals, time of loading, origin and destination, and loaded weight before and after transport. In contrast to fat cattle, feeder cattle exhibited greater shrink (4.9 vs. 7.9 ± 0.2% of BW, respectively; P < 0.01), and experienced longer total transport durations (12.4 vs. 14.9 ± 0.99, respectively; P < 0.01) due to border crossing protocols which require mandatory animal inspection. Shrink was greater (P < 0.001) for feeder cattle loaded at ranches/farms and feed yards compared with those loaded at auction markets. Cattle loaded during the afternoon and evening shrank more than those loaded during the night and morning (P < 0.05). Shrinkage was less in cattle transported by truck drivers having 6 or more years of experience hauling livestock compared with those with 5 yr or less (P < 0.05). Shrink increased with both midpoint ambient temperature (% of BW/°C; P < 0.001) and time on truck (% of BW/h; P < 0.001). Temperature and time on truck had a multiplicative effect on each other because shrink increased most rapidly in cattle transported for both longer durations and at higher ambient temperatures (P < 0.001). The rate of shrink over time (% of BW/h) was greatest in cull cattle, intermediate in calves and feeder cattle, and slowest in fat cattle (P < 0.05) but such differences disappeared when the effects of place of origin, loading time, and experience of truck drivers were included in the model. Cull cattle, calves and feeder cattle appear to be more affected by transport compared with fat cattle going to slaughter because of greater shrink. Several factors should be considered when developing guidelines to reduce cattle transport stress and shrink including type

  20. Radionuclide and radiation protection data handbook 2nd edition (2002).

    PubMed

    Delacroix, D; Guerre, J P; Leblanc, P; Hickman, C

    2002-01-01

    This handbook is a reference source of radionuclide and radiation protection information. Its purpose is to provide users of radionuclides in medicine, research and industry with consolidated and appropriate information and data to handle and transport radioactive substances safely. It is mainly intended for users in low and intermediate activity laboratories. Individual data sheets are provided for a wide range of commonly used radionuclides (144 in total). These radionuclides are classified into five different groups as a function of risk level, represented by colours red, orange, yellow, green and blue, in descending order of risk.

  1. Radionuclide migration as a function of mineralogy

    SciTech Connect

    Triay, I.R.; Mitchell, A.J.; Ott, M.A.

    1991-02-01

    The migration of radionuclides is studied as a function of mineralogy utilizing batch sorption and column experiments. The transport behavior of alkaline, alkaline-earth, and transition metals, and actinide species is studied in pure mineral separates. The solid phases utilized for these investigations are silicates, alumino-silicates, carbonates, and metal oxides and oxyhydroxides. The results of this effort are utilized to aid in the elucidation of the dominant chemical mechanisms of radionuclide migration, the prediction of radionuclide transport in conditions similar to those expected at the proposed high-level nuclear waste repository at Yucca Mountain, Nevada, and the identification of materials that act as natural geological barriers or that can be utilized as strong sorbers in engineered barriers. 9 refs., 2 figs., 2 tabs.

  2. Radionuclide removal by apatite

    SciTech Connect

    Rigali, Mark J.; Brady, Patrick V.; Moore, Robert C.

    2016-12-01

    In this study, a growing body of research supports widespread future reliance on apatite for radioactive waste cleanup. Apatite is a multi-functional radionuclide sorbent that lowers dissolved radionuclide concentrations by surface sorption, ion exchange, surface precipitation, and by providing phosphate to precipitate low-solubility radionuclide-containing minerals. Natural apatites are rich in trace elements, and apatite’s stability in the geologic record suggest that radionuclides incorporated into apatite, whether in a permeable reactive barrier or a waste form, are likely to remain isolated from the biosphere for long periods of time. Here we outline the mineralogic and surface origins of apatite-radionuclide reactivity and show how apatites might be used to environmental advantage in the future.

  3. Radionuclide removal by apatite

    DOE PAGES

    Rigali, Mark J.; Brady, Patrick V.; Moore, Robert C.

    2016-12-01

    In this study, a growing body of research supports widespread future reliance on apatite for radioactive waste cleanup. Apatite is a multi-functional radionuclide sorbent that lowers dissolved radionuclide concentrations by surface sorption, ion exchange, surface precipitation, and by providing phosphate to precipitate low-solubility radionuclide-containing minerals. Natural apatites are rich in trace elements, and apatite’s stability in the geologic record suggest that radionuclides incorporated into apatite, whether in a permeable reactive barrier or a waste form, are likely to remain isolated from the biosphere for long periods of time. Here we outline the mineralogic and surface origins of apatite-radionuclide reactivity andmore » show how apatites might be used to environmental advantage in the future.« less

  4. Yeast culture supplement during nursing and transport affects immunity and intestinal microbial ecology of weanling pigs.

    PubMed

    Weedman, S M; Rostagno, M H; Patterson, J A; Yoon, I; Fitzner, G; Eicher, S D

    2011-06-01

    The objectives of this study were to determine the influence of a Saccharomyces cerevisiae fermentation product on innate immunity and intestinal microbial ecology after weaning and transport stress. In a randomized complete block design, before weaning and in a split-plot analysis of a 2 × 2 factorial arrangement of yeast culture (YY) and transport (TT) after weaning, 3-d-old pigs (n = 108) were randomly assigned within litter (block) to either a control (NY, milk only) or yeast culture diet (YY; delivered in milk to provide 0.1 g of yeast culture product/kg of BW) from d 4 to 21. At weaning (d 21), randomly, one-half of the NY and YY pigs were assigned to a 6-h transport (NY-TT and YY-TT) before being moved to nursery housing, and the other one-half were moved directly to nursery housing (NY-NT and YY-NT, where NT is no transport). The yeast treatment was a 0.2% S. cerevisiae fermentation product and the control treatment was a 0.2% grain blank in feed for 2 wk. On d 1 before transport and on d 1, 4, 7, and 14 after transport, blood was collected for leukocyte assays, and mesenteric lymph node, jejunal, and ileal tissue, and jejunal, ileal, and cecal contents were collected for Toll-like receptor expression (TLR); enumeration of Escherichia coli, total coliforms, and lactobacilli; detection of Salmonella; and microbial analysis. After weaning, a yeast × transport interaction for ADG was seen (P = 0.05). Transport affected (P = 0.09) ADFI after weaning. Yeast treatment decreased hematocrit (P = 0.04). A yeast × transport interaction was found for counts of white blood cells (P = 0.01) and neutrophils (P = 0.02) and for the neutrophil-to-lymphocyte ratio (P = 0.02). Monocyte counts revealed a transport (P = 0.01) effect. Interactions of yeast × transport (P = 0.001) and yeast × transport × day (P = 0.09) for TLR2 and yeast × transport (P = 0.08) for TLR4 expression in the mesenteric lymph node were detected. Day affected lactobacilli, total coliform, and E

  5. Interacting Physical and Biological Processes Affecting Nutrient Transport Through Human Dominated Landscapes

    NASA Astrophysics Data System (ADS)

    Finlay, J. C.

    2015-12-01

    Human activities increasingly dominate biogeochemical cycles of limiting nutrients on Earth. Urban and agricultural landscapes represent the largest sources of excess nutrients that drive water quality degradation. The physical structure of both urban and agricultural watersheds has been extensively modified, and these changes have large impacts on water and nutrient transport. Despite strong physical controls over nutrient transport in human dominated landscapes, biological processes play important roles in determining the fates of both nitrogen and phosphorus. This talk uses examples from research in urban and agricultural watersheds in the Midwestern USA to illustrate interactions of physical and biological controls over nutrient cycles that have shifted nitrogen (N) and phosphorus (P) sources and cycling in unexpected ways in response to management changes. In urban watersheds, efforts to improve water quality have been hindered by legacy sources of phosphorus added to storm water through transport to drainage systems by vegetation. Similarly, reductions in field erosion in agricultural watersheds have not led to major reductions in phosphorus transport, because of continued release of biological sources of P. Where management of phosphorus has been most effective in reducing eutrophication of lakes, decreases in N removal processes have led to long term increases in N concentration and transport. Together, these examples show important roles for biological processes affecting nutrient movement in highly modified landscapes. Consideration of the downstream physical and biological responses of management changes are thus critical toward identification of actions that will most effectively reduce excess nutrients watersheds and coastal zones.

  6. Affective Neural Responses Modulated by Serotonin Transporter Genotype in Clinical Anxiety and Depression

    PubMed Central

    Oathes, Desmond J.; Hilt, Lori M.; Nitschke, Jack B.

    2015-01-01

    Serotonin transporter gene variants are known to interact with stressful life experiences to increase chances of developing affective symptoms, and these same variants have been shown to influence amygdala reactivity to affective stimuli in non-psychiatric populations. The impact of these gene variants on affective neurocircuitry in anxiety and mood disorders has been studied less extensively. Utilizing a triallelic assay (5-HTTLPR and rs25531) to assess genetic variation linked with altered serotonin signaling, this fMRI study investigated genetic influences on amygdala and anterior insula activity in 50 generalized anxiety disorder patients, 26 of whom also met DSM-IV criteria for social anxiety disorder and/or major depressive disorder, and 39 healthy comparison subjects. A Group x Genotype interaction was observed for both the amygdala and anterior insula in a paradigm designed to elicit responses in these brain areas during the anticipation of and response to aversive pictures. Patients who are S/LG carriers showed less activity than their LA/LA counterparts in both regions and less activity than S/LG healthy comparison subjects in the amygdala. Moreover, patients with greater insula responses reported higher levels of intolerance of uncertainty, an association that was particularly pronounced for patients with two LA alleles. A genotype effect was not established in healthy controls. These findings link the serotonin transporter gene to affective circuitry findings in anxiety and depression psychopathology and further suggest that its impact on patients may be different from effects typically observed in healthy populations. PMID:25675343

  7. TYBO/BENHAM: Model Analysis of Groundwater Flow and Radionuclide Migration from Underground Nuclear Tests in Southwestern Pahute Mesa, Nevada

    SciTech Connect

    Andrew Wolfsberg; Lee Glascoe; Guoping Lu; Alyssa Olson; Peter Lichtner; Maureen McGraw; Terry Cherry; Guy Roemer

    2002-09-01

    Recent field studies have led to the discovery of trace quantities of plutonium originating from the BENHAM underground nuclear test in two groundwater observation wells on Pahute Mesa at the Nevada Test Site. These observation wells are located 1.3 km from the BENHAM underground nuclear test and approximately 300 m from the TYBO underground nuclear test. In addition to plutonium, several other conservative (e.g. tritium) and reactive (e.g. cesium) radionuclides were found in both observation wells. The highest radionuclide concentrations were found in a well sampling a welded tuff aquifer more than 500m above the BENHAM emplacement depth. These measurements have prompted additional investigations to ascertain the mechanisms, processes, and conditions affecting subsurface radionuclide transport in Pahute Mesa groundwater. This report describes an integrated modeling approach used to simulate groundwater flow, radionuclide source release, and radionuclide transport near the BENHAM and TYBO underground nuclear tests on Pahute Mesa. The components of the model include a flow model at a scale large enough to encompass many wells for calibration, a source-term model capable of predicting radionuclide releases to aquifers following complex processes associated with nonisothermal flow and glass dissolution, and site-scale transport models that consider migration of solutes and colloids in fractured volcanic rock. Although multiple modeling components contribute to the methodology presented in this report, they are coupled and yield results consistent with laboratory and field observations. Additionally, sensitivity analyses are conducted to provide insight into the relative importance of uncertainty ranges in the transport parameters.

  8. Advances in Understanding Sorption and Transport Processes Affecting the Fate of Environmental Pollutants in the Subsurface

    NASA Astrophysics Data System (ADS)

    Karapanagioti, H. K.; Werner, D.; Werth, C.

    2012-04-01

    The results of a call for a special issue that is now in press by the Journal of Contaminant Hydrology will be presented. This special issue is edited by the authors and is entitled "Sorption and Transport Processes Affecting the Fate of Environmental Pollutants in the Subsurface". A short abstract of each paper will be presented along with the most interesting results. Nine papers were accepted. Pollutants studied include: biocolloids, metals (arsenic, chromium, nickel), organic compounds such as hydrocarbons, chlorinated hydrocarbons, micropollutants (PAHs, PCBs), pesticides (glyphosate, 2,4-D). Findings presented in the papers include a modified batch reactor system to study equilibrium-reactive transport problems of metals. Column studies along with theoretical approximations evaluate the combined effects of grain size and pore water velocity on the transport in water saturated porous media of three biocolloids. A polluted sediment remediation method is evaluated considering site-specific conditions through monitoring results and modelling. A field study points to glogging and also sorption as mechanisms affecting the effectiveness of sub-surface flow constructed wetlands. A new isotherm model combining modified traditionally used isotherms is proposed that can be used to simulate pH-dependent metal adsorption. Linear free energy relationships (LFERs) demonstrate ability to predict slight isotope shifts into the groundwater due to sorption. Possible modifications that improve the reliability of kinetic models and parameter values during the evaluation of experiments that assess the sorption of pesticides on soils are tested. Challenges in selecting groundwater pollutant fate and transport models that account for the effect of grain-scale sorption rate limitations are evaluated based on experimental results and are discussed based on the Damköhler number. Finally, a thorough review paper presents the impact of mineral micropores on the transport and fate of

  9. Methane transport and emissions from soil as affected by water table and vascular plants

    PubMed Central

    2013-01-01

    Background The important greenhouse gas (GHG) methane is produced naturally in anaerobic wetland soils. By affecting the production, oxidation and transport of methane to the atmosphere, plants have a major influence upon the quantities emitted by wetlands. Different species and functional plant groups have been shown to affect these processes differently, but our knowledge about how these effects are influenced by abiotic factors such as water regime and temperature remains limited. Here we present a mesocosm experiment comparing eight plant species for their effects on internal transport and overall emissions of methane under contrasting hydrological conditions. To quantify how much methane was transported internally through plants (the chimney effect), we blocked diffusion from the soil surface with an agar seal. Results We found that graminoids caused higher methane emissions than forbs, although the emissions from mesocosms with different species were either lower than or comparable to those from control mesocosms with no plant (i.e. bare soil). Species with a relatively greater root volume and a larger biomass exhibited a larger chimney effect, though overall methane emissions were negatively related to plant biomass. Emissions were also reduced by lowering the water table. Conclusions We conclude that plant species (and functional groups) vary in the degree to which they transport methane to the atmosphere. However, a plant with a high capacity to transport methane does not necessarily emit more methane, as it may also cause more rhizosphere oxidation of methane. A shift in plant species composition from graminoids to forbs and/or from low to high productive species may lead to reduction of methane emissions. PMID:24010540

  10. Assessment of individual radionuclide distributions from the Fukushima nuclear accident covering central-east Japan

    PubMed Central

    Kinoshita, Norikazu; Sueki, Keisuke; Sasa, Kimikazu; Kitagawa, Jun-ichi; Ikarashi, Satoshi; Nishimura, Tomohiro; Wong, Ying-Shee; Satou, Yukihiko; Handa, Koji; Takahashi, Tsutomu; Sato, Masanori; Yamagata, Takeyasu

    2011-01-01

    A tremendous amount of radioactivity was discharged because of the damage to cooling systems of nuclear reactors in the Fukushima No. 1 nuclear power plant in March 2011. Fukushima and its adjacent prefectures were contaminated with fission products from the accident. Here, we show a geographical distribution of radioactive iodine, tellurium, and cesium in the surface soils of central-east Japan as determined by gamma-ray spectrometry. Especially in Fukushima prefecture, contaminated area spreads around Iitate and Naka-Dori for all the radionuclides we measured. Distributions of the radionuclides were affected by the physical state of each nuclide as well as geographical features. Considering meteorological conditions, it is concluded that the radioactive material transported on March 15 was the major contributor to contamination in Fukushima prefecture, whereas the radioactive material transported on March 21 was the major source in Ibaraki, Tochigi, Saitama, and Chiba prefectures and in Tokyo. PMID:22084070

  11. Hydrologic and geochemical controls on the transport of radionuclides in natural undisturbed arid environments as determined by accelerator mass spectrometry measurements

    SciTech Connect

    Nimz, G; Caffee, M W; McAninch, J

    2000-04-01

    This project developed techniques for measuring globally distributed radionuclides that occur today in extremely low abundances (''fallout'' from the era of atmospheric nuclear testing), and then applied these techniques to better understand the mechanisms by which radionuclides migrate. The techniques employ accelerator mass spectrometry (AMS), a relatively new analytical tool that permits this work to be conducted for the first time. The goal in this project was to develop AMS analytical techniques for {sup 129}I (fallout concentration: {approx} 10{sup 6} atoms/g) {sup 99}Tc ({approx} 10{sup 9} atoms/g), {sup 90}Sr ({approx}10{sup 7} atoms/gram soil), and {sup 93}Zr ({approx} 10{sup 9} atoms/g), and improved methods for {sup 36}Cl ({approx} 10{sup 9} atoms/g). As a demonstration of the analytical techniques, and as an investigation of identified problems associated with characterizing moisture and radionuclide movement in unsaturated desert soils, we developed a vadose zone research site at the Nevada Test Site. Our findings can be summarized as follows: (1) The distribution of chloride and {sup 36}Cl at the research site indicates that the widely-used ''chloride accumulation'' method for estimating moisture flux is erroneous; some mechanism for attenuation of chloride exists, violating an assumption of the accumulation method; (2) {sup 129}I is fractionated into several soil compartments that have varying migration abilities; the two most mobile can be tentatively identified as Fe/Mn oxyhydroxides and organic acids based on our sequential leaching techniques; (3) These most mobile constituents are capable of migrating at a rate greater than that of {sup 36}Cl, usually considered the most mobile solute in hydrologic systems; these constituents may be colloidal in character, of neutral surface charge, and therefore conservative in aqueous migration; (4) {sup 99}Tc is readily measurable by AMS, as we demonstrate by the first AMS {sup 99}Tc measurements of

  12. Multi-walled carbon nanotubes affect drug transport across cell membrane in rat astrocytes

    NASA Astrophysics Data System (ADS)

    Chen, Xiao; Schluesener, Hermann J.

    2010-03-01

    The impact of carbon nanotubes on the cell membrane is an aspect of particular importance and interest in the study of carbon nanotubes' interactions with living systems. One of the many functions of the cell membrane is to execute substance transport into and out of the cell. We investigated the influence of multi-walled carbon nanotubes (MWCNTs) on the transport of several compounds across in the cell membrane of rat astrocytes using flow cytometry. These compounds are fluorescein diacetate, carboxyfluorescein diacetate, rhodamine 123 and doxorubicin, which are prosubstrate/substrates of multidrug transporter proteins. Results showed that MWCNTs significantly inhibited cellular uptake of doxorubicin but not the other drugs and the mode of loading made a significant difference in doxorubicin uptake. Retention of fluorescein, carboxyfluorescein and rhodamine 123 was remarkably higher in MWCNT-exposed cells after an efflux period. A kinetics study also demonstrated slower efflux of intracellular fluorescein and rhodamine 123. Data presented in this paper suggest that MWCNTs could affect drug transport across cell membranes. The implications of the findings are discussed.

  13. Radionuclides in US coals

    SciTech Connect

    Bisselle, C. A.; Brown, R. D.

    1984-03-01

    The current state of knowledge with respect to radionuclide concentrations in US coals is discussed. Emphasis is placed on the levels of uranium in coal (and lignite) which are considered to represent a concern resulting from coal combustion; areas of the US where such levels have been found; and possible origins of high radionuclide levels in coal. The report reviews relevant studies and presents new data derived from a computerized search of radionuclide content in about 4000 coal samples collected throughout the coterminous US. 103 references, 5 figures, 5 tables.

  14. The effect of carbonate soil on transport and dose estimates for long-lived radionuclides at a U.S. Pacific test site

    SciTech Connect

    Conrado, C L; Hamilton, T F; Robison, W L; Stoker, A C

    1999-01-01

    The US conducted a series of nuclear tests from 1946 to 1958 at Bikini, a coral atoll, in the Marshall Islands (MI). The aquatic and terrestrial environments of the atoll are still contaminated with several long-lived radionuclides that were generated during testing. The four major radionuclides found in terrestrial plants and soils are Cesium-137 ({sup 137}Cs), Strontium-90 ({sup 90}Sr), Plutonium-239+240 ({sup 239+240}Pu) and Americium-241 ({sup 241}Am). {sup 137}Cs in the coral soils is more available for uptake by plants than {sup 137}Cs associated with continental soils of North America or Europe. Soil-to-plant {sup 137}Cs median concentration ratios (CR) (kBq kg{sup {minus}1} dry weight plant/kBq kg{sup {minus}1} dry weight soil) for tropical fruits and vegetables range between 0.8 and 36, much larger than the range of 0.005 to 0.5 reported for vegetation in temperate zones. Conversely, {sup 90}Sr median CRs range from 0.006 to 1.0 at the atoll versus a range from 0.02 to 3.0 for continental silica-based soils. Thus, the relative uptake of {sup 137}Cs and {sup 90}Sr by plants in carbonate soils is reversed from that observed in silica-based soils. The CRs for {sup 239+240}Pu and {sup 241}Am are very similar to those observed in continental soils. Values range from 10{sup {minus}6} to 10{sup {minus}4} for both {sup 239+240}Pu and {sup 241}Am. No significant difference is observed between the two in coral soil.

  15. Natural radionuclide of Po210 in the edible seafood affected by coal-fired power plant industry in Kapar coastal area of Malaysia

    PubMed Central

    2011-01-01

    Background Po210 can be accumulated in various environmental materials, including marine organisms, and contributes to the dose of natural radiation in seafood. The concentration of this radionuclide in the marine environment can be influenced by the operation of a coal burning power plant but existing studies regarding this issue are not well documented. Therefore, the aim of this study was to estimate the Po210 concentration level in marine organisms from the coastal area of Kapar, Malaysia which is very near to a coal burning power plant station and to assess its impact on seafood consumers. Methods Concentration of Po210 was determined in the edible muscle of seafood and water from the coastal area of Kapar, Malaysia using radiochemical separation and the Alpha Spectrometry technique. Results The activities of Po210 in the dissolved phase of water samples ranged between 0.51 ± 0.21 and 0.71 ± 0.24 mBql-1 whereas the particulate phase registered a range of 50.34 ± 11.40 to 72.07 ± 21.20 Bqkg-1. The ranges of Po210 activities in the organism samples were 4.4 ± 0.12 to 6.4 ± 0.95 Bqkg-1 dry wt in fish (Arius maculatus), 45.7 ± 0.86 to 54.4 ± 1.58 Bqkg-1 dry wt in shrimp (Penaeus merguiensis) and 104.3 ± 3.44 to 293.8 ± 10.04 Bqkg-1 dry wt in cockle (Anadara granosa). The variation of Po210 in organisms is dependent on the mode of their life style, ambient water concentration and seasonal changes. The concentration factors calculated for fish and molluscs were higher than the recommended values by the IAEA. An assessment of daily intake and received dose due to the consumption of seafood was also carried out and found to be 2083.85 mBqday-1person-1 and 249.30 μSvyr-1 respectively. These values are comparatively higher than reported values in other countries. Moreover, the transformation of Po210 in the human body was calculated and revealed that a considerable amount of Po210 can be absorbed in the internal organs. The calculated values of life time

  16. Radionuclide imaging of osteomyelitis.

    PubMed

    Palestro, Christopher J

    2015-01-01

    Radionuclide procedures frequently are performed as part of the diagnostic workup of osteomyelitis. Bone scintigraphy accurately diagnoses osteomyelitis in bones not affected by underlying conditions. Degenerative joint disease, fracture, and orthopedic hardware decrease the specificity of the bone scan, making it less useful in these situations. Gallium-67 scintigraphy was often used as an adjunct to bone scintigraphy for diagnosing osteomyelitis. However, now it is used primarily for spinal infections when (18)F-FDG imaging cannot be performed. Except for the spine, in vitro-labeled leukocyte imaging is the nuclear medicine test of choice for diagnosing complicating osteomyelitis. Leukocytes accumulate in bone marrow as well as in infection. Performing complementary bone marrow imaging with (99m)Tc-sulfur colloid facilitates the differentiation between osteomyelitis and normal marrow and improves test overall accuracy. Antigranulocyte antibodies and antibody fragments, such as (99m)Tc-besilesomab and (99m)Tc-sulesomab, were developed to eliminate the disadvantages associated with in vitro-labeled leukocytes. These agents, however, have their own shortcomings and are not widely available. As biotin is used as a growth factor by certain bacteria, (111)In-biotin is useful to diagnose spinal infections. Radiolabeled synthetic fragments of ubiquicidin, a naturally occurring human antimicrobial peptide that targets bacteria, can differentiate infection from sterile inflammation and may be useful to monitor response to treatment. (18)F-FDG is extremely useful in the diagnostic workup of osteomyelitis. Sensitivity in excess of 95% and specificity ranging from 75%-99% have been reported. (18)F-FDG is the radionuclide test of choice for spinal infection. The test is sensitive, with a high negative predictive value, and reliably differentiates degenerative from infectious vertebral body end-plate abnormalities. Data on the accuracy of (18)F-FDG for diagnosing diabetic pedal

  17. Radionuclides in Diagnosis.

    ERIC Educational Resources Information Center

    Williams, E. D.

    1989-01-01

    Discussed is a radionuclide imaging technique, including the gamma camera, image analysis computer, radiopharmaceuticals, and positron emission tomography. Several pictures showing the use of this technique are presented. (YP)

  18. Geomorphic control of radionuclide diffusion in desert soils

    NASA Astrophysics Data System (ADS)

    Pelletier, Jon D.; Harrington, Charles D.; Whitney, John W.; Cline, Michael; DeLong, Stephen B.; Keating, Gordon; Ebert, K. Teryn

    2005-12-01

    Diffusion is a standard model for the vertical migration of radionuclides in soil profiles. Here we show that diffusivity values inferred from fallout 137Cs profiles in soils on the Fortymile Wash alluvial fan, Nye County, Nevada, have a strong inverse correlation with the age of the geomorphic surface. This result suggests that radionuclide-bound particles are predominantly transported by infiltration rather than by bulk-mixing processes such as wetting/drying, freeze/thaw, and bioturbation. Our results provide a preliminary basis for using soil-geomorphic mapping, point-based calibration data, and the diffusion model to predict radionuclide transport in desert soils within a pedotransfer-function approach.

  19. The effect of stagnant water zones on retarding radionuclide stransport in fractured rocks: An extension to the Channel Network Model

    NASA Astrophysics Data System (ADS)

    Shahkarami, Pirouz; Liu, Longcheng; Moreno, Luis; Neretnieks, Ivars

    2016-09-01

    over the short time-scale of the tracer experiment, the effect of diffusion into STWZs is not as pronounced as that of matrix diffusion directly from the flow channel, and the latter remains the main retarding mechanism. Predictions for longer time-scale, tens of years and more, show that the effect of STWZs becomes strong and tends to increase with transport time. It is shown that over the long times of interest for safety assessment of radioactive waste repositories, STWZs can substantially contribute to radionuclide retardation, though for the short time-scales the impact is not very strong and is not expected to affect the results of short-term field experiments.

  20. A Non-Electrostatic Surface Complexation Approach to Modeling Radionuclide Migration at the Nevada Test Site: I. Iron Oxides and Calcite

    SciTech Connect

    Zavarin, M; Bruton, C J

    2004-12-17

    Reliable quantitative prediction of contaminant transport in subsurface environments is critical to evaluating the risks associated with radionuclide migration. As part of the Underground Test Area (UGTA) project, radionuclide transport away from various underground nuclear tests conducted in the saturated zone at the Nevada Test Site (NTS) is being examined. In the near-field environment, reactive transport simulations must account for changes in water chemistry and mineralogy as a function of time and their effect on radionuclide migration. Unlike the K{sub d} approach, surface complexation (SC) reactions, in conjunction with ion exchange and precipitation, can be used to describe radionuclide reactive transport as a function of changing environmental conditions. They provide a more robust basis for describing radionuclide retardation in geochemically dynamic environments. The interaction between several radionuclides considered relevant to the UGTA project and iron oxides and calcite are examined in this report. The interaction between these same radionuclides and aluminosilicate minerals is examined in a companion report (Zavarin and Bruton, 2004). Selection criteria for radionuclides were based on abundance, half-life, toxicity to human and environmental health, and potential mobility at NTS (Tompson et al., 1999). Both iron oxide and calcite minerals are known to be present at NTS in various locations and are likely to affect radionuclide migration from the near-field. Modeling the interaction between radionuclides and these minerals was based on surface complexation. The effectiveness of the most simplified SC model, the one-site Non-Electrostatic Model (NEM), to describe sorption under various solution conditions is evaluated in this report. NEM reactions were fit to radionuclide sorption data available in the literature, as well as sorption data recently collected for the UGTA project, and a NEM database was developed. For radionuclide-iron oxide sorption

  1. Method and apparatus for separating radionuclides from non-radionuclides

    DOEpatents

    Harp, Richard J.

    1990-01-01

    In an apparatus for separating radionuclides from non-radionuclides in a mixture of nuclear waste, a vessel is provided wherein the mixture is heated to a temperature greater than the temperature of vaporization for the non-radionuclides but less than the temperature of vaporization for the radionuclides. Consequently the non-radionuclides are vaporized while the non-radionuclides remain the solid or liquid state. The non-radionuclide vapors are withdrawn from the vessel and condensed to produce a flow of condensate. When this flow decreases the heat is reduced to prevent temperature spikes which might otherwise vaporize the radionuclides. The vessel is removed and capped with the radioactive components of the apparatus and multiple batches of the radionuclide residue disposed therein. Thus the vessel ultimately provides a burial vehicle for all of the radioactive components of the process.

  2. Role of Reservoirs in Radionuclide Transport in the River Systems: Comparative Analyses for the Rivers of the Chernobyl and Fukushima Fallout Zones

    NASA Astrophysics Data System (ADS)

    Zheleznyak, Mark; Kivva, , Sergei; Konoplev, Alexei; Nanba, Kenji; Onda, Yuichi

    2015-04-01

    The 1986 accident at the Chernobyl Nuclear Power Plant (ChNPP), Ukraine, caused a significant radioactive contamination of the Dnieper River basin, and, in particular, the Pripyat River watershed. The ChNPP is situated approximately 30 km from the confluence of the Pripyat River with the Kiev Reservoir of the Dnieper river. The watersheds and floodplain territory in the vicinity of the ChNPP and the surrounding watersheds (including those in Russia and Belarus) are heavy contaminated by 137Cs and 90Sr. From these contaminated areas, radionuclides migrate into the Kiev Reservoir, and, consequently, downstream along the cascade of six Dnieper reservoirs toward the Black Sea. Spring flood events, generated by snow melting, and periodic rainfall floods in the Pripyat River watershed lead to elevated levels of radioactive contamination of the water supply sources for the Ukrainian population consuming the Dnieper River water downstream from Kiev. The 2011 accident at the Fukushima Daiichi NPP, Japan caused 137Cs contamination of the watersheds of Abukuma River - the largest river of the fallout area, and the number of the rivers crossing the heavy contaminated "no exit" territories and flowing to the populated areas of the Fukushima Prefecture. There are deep reservoirs on some of these rivers at Mano Dam - Manogawa River, at Yokokawa Dam - Otagawa River, Takanakura Dam - Mizunashi Gawa River. In both cases - after Chernobyl accident and after Fukushima accident the reservoirs play a role of the "traps" for the contaminated sediments. However the potential risks of the secondary remobilization of 137Cs during the extreme events - the highest floods of in a cases of the dam breaks should be studied as a part of the post accidental radiation safety analyses. The objective of this presentation is to provide an overview of the results of the monitoring of radionuclide fate in the rivers and reservoirs of the Dnieper River basin in comparison with the data for the rivers and

  3. Radionuclide Retention in Concrete Wasteforms - FY13

    SciTech Connect

    Snyder, Michelle MV; Golovich, Elizabeth C.; Wellman, Dawn M.; Crum, Jarrod V.; Lapierre, Robert; Dage, Denomy C.; Parker, Kent E.; Cordova, Elsa A.

    2013-10-15

    Assessing long-term performance of Category 3 waste cement grouts for radionuclide encasement requires knowledge of the radionuclide-cement interactions and mechanisms of retention (i.e., sorption or precipitation); the mechanism of contaminant release; the significance of contaminant release pathways; how wasteform performance is affected by the full range of environmental conditions within the disposal facility; the process of wasteform aging under conditions that are representative of processes occurring in response to changing environmental conditions within the disposal facility; the effect of wasteform aging on chemical, physical, and radiological properties; and the associated impact on contaminant release. This knowledge will enable accurate prediction of radionuclide fate when the wasteforms come in contact with groundwater. Data collected throughout the course of this work will be used to quantify the efficacy of concrete wasteforms, similar to those used in the disposal of low-level waste and mixed low-level waste, for the immobilization of key radionuclides (i.e., uranium, technetium, and iodine). Data collected will also be used to quantify the physical and chemical properties of the concrete affecting radionuclide retention.

  4. Does Membrane Thickness Affect the Transport of Selective Ions Mediated by Ionophores in Synthetic Membranes?

    PubMed

    Lomora, Mihai; Dinu, Ionel Adrian; Itel, Fabian; Rigo, Serena; Spulber, Mariana; Palivan, Cornelia G

    2015-08-31

    Biomimetic polymer nanocompartments (polymersomes) with preserved architecture and ion-selective membrane permeability represent cutting-edge mimics of cellular compartmentalization. Here it is studied whether the membrane thickness affects the functionality of ionophores in respect to the transport of Ca(2+) ions in synthetic membranes of polymersomes, which are up to 2.6 times thicker than lipid membranes (5 nm). Selective permeability toward calcium ions is achieved by proper insertion of ionomycin, and demonstrated by using specific fluorescence markers encapsulated in their inner cavities. Preservation of polymersome architecture is shown by a combination of light scattering, transmission electron microscopy, and fluorescence spectroscopy. By using a combination of stopped-flow and fluorescence spectroscopy, it is shown that ionomycin can function and transport calcium ions across polymer membranes with thicknesses in the range 10.7-13.4 nm (7.1-8.9 times larger than the size of the ionophore). Thicker membranes induce a decrease in transport, but do not block it due to the intrinsic flexibility of these synthetic membranes. The design of ion selective biomimetic nanocompartments represents a new path toward the development of cellular ion nanosensors and nano-reactors, in which calcium sensitive biomacromolecules can be triggered for specific biological functions.

  5. Activity of erdosteine on mucociliary transport in patients affected by chronic bronchitis.

    PubMed

    Olivieri, D; Del Donno, M; Casalini, A; D'Ippolito, R; Fregnan, G B

    1991-01-01

    The influence of erdosteine (a mucomodulator endowed with mucolytic and antioxidant properties) on human mucociliary transport (MCT) was investigated in a double-blind placebo controlled study. Sixteen former smokers affected by chronic bronchitis, preselected for their mucociliary responsiveness to an inhaled beta 2-agonist, were divided into two groups (matched by number, sex, age and FEV1%) and orally treated with placebo or erdosteine (300 mg t.i.d.) for 8 days. Their MCT was assessed by the bronchofiberscopy technique just before starting the treatment and at the end of the treatment. The pretreatment mucus transport velocity in these patients was significantly decreased with respect to healthy subjects. The erdosteine treatment induced a significant improvement of MCT while placebo was inactive (mean % variation +/- SE against their baseline values being +60.4 +/- 18.4 and -3.0 +/- 5.9, respectively). This peculiar activity of erdosteine on mucus transport may be of clinical usefulness in chronic bronchitic patients and it can be added to beta 2-agonist to restore the decreased MCT.

  6. Illicit Trafficking of Natural Radionuclides

    NASA Astrophysics Data System (ADS)

    Friedrich, Steinhäusler; Lyudmila, Zaitseva

    2008-08-01

    Natural radionuclides have been subject to trafficking worldwide, involving natural uranium ore (U 238), processed uranium (yellow cake), low enriched uranium (<20% U 235) or highly enriched uranium (>20% U 235), radium (Ra 226), polonium (Po 210), and natural thorium ore (Th 232). An important prerequisite to successful illicit trafficking activities is access to a suitable logistical infrastructure enabling an undercover shipment of radioactive materials and, in case of trafficking natural uranium or thorium ore, capable of transporting large volumes of material. Covert en route diversion of an authorised uranium transport, together with covert diversion of uranium concentrate from an operating or closed uranium mines or mills, are subject of case studies. Such cases, involving Israel, Iran, Pakistan and Libya, have been analyzed in terms of international actors involved and methods deployed. Using international incident data contained in the Database on Nuclear Smuggling, Theft and Orphan Radiation Sources (DSTO) and international experience gained from the fight against drug trafficking, a generic Trafficking Pathway Model (TPM) is developed for trafficking of natural radionuclides. The TPM covers the complete trafficking cycle, ranging from material diversion, covert material transport, material concealment, and all associated operational procedures. The model subdivides the trafficking cycle into five phases: (1) Material diversion by insider(s) or initiation by outsider(s); (2) Covert transport; (3) Material brokerage; (4) Material sale; (5) Material delivery. An Action Plan is recommended, addressing the strengthening of the national infrastructure for material protection and accounting, development of higher standards of good governance, and needs for improving the control system deployed by customs, border guards and security forces.

  7. Illicit Trafficking of Natural Radionuclides

    SciTech Connect

    Friedrich, Steinhaeusler; Lyudmila, Zaitseva

    2008-08-07

    Natural radionuclides have been subject to trafficking worldwide, involving natural uranium ore (U 238), processed uranium (yellow cake), low enriched uranium (<20% U 235) or highly enriched uranium (>20% U 235), radium (Ra 226), polonium (Po 210), and natural thorium ore (Th 232). An important prerequisite to successful illicit trafficking activities is access to a suitable logistical infrastructure enabling an undercover shipment of radioactive materials and, in case of trafficking natural uranium or thorium ore, capable of transporting large volumes of material. Covert en route diversion of an authorised uranium transport, together with covert diversion of uranium concentrate from an operating or closed uranium mines or mills, are subject of case studies. Such cases, involving Israel, Iran, Pakistan and Libya, have been analyzed in terms of international actors involved and methods deployed. Using international incident data contained in the Database on Nuclear Smuggling, Theft and Orphan Radiation Sources (DSTO) and international experience gained from the fight against drug trafficking, a generic Trafficking Pathway Model (TPM) is developed for trafficking of natural radionuclides. The TPM covers the complete trafficking cycle, ranging from material diversion, covert material transport, material concealment, and all associated operational procedures. The model subdivides the trafficking cycle into five phases: (1) Material diversion by insider(s) or initiation by outsider(s); (2) Covert transport; (3) Material brokerage; (4) Material sale; (5) Material delivery. An Action Plan is recommended, addressing the strengthening of the national infrastructure for material protection and accounting, development of higher standards of good governance, and needs for improving the control system deployed by customs, border guards and security forces.

  8. Radionuclide Mobility at the Nevada Test Site

    SciTech Connect

    Hu, Q; Smith, D; Rose, T; Glascoe, L; Steefel, C; Zavarin, M

    2003-11-13

    Underground nuclear tests conducted at the Nevada Test Site (NTS) are characterized by abundant fission product and actinide source terms. Included are {sup 99}Tc and other soluble radionuclides ({sup 3}H, {sup 14}C, {sup 36}Cl, {sup 85}Kr, and {sup 129}I), which are presumably mobile in groundwater and potentially toxic to down-gradient receptors. NTS provides the Office of Civilian Radioactive Waste Management (OCRWM) with an analog of the release of these radionuclides from a nuclear waste repository in the absence of engineered barriers. The investigation described in this report synthesizes a substantial body of data collected on the identity and distribution of soluble radionuclides at field scales over distances of hundreds of meters, for durations up to 40 years, and under hydrogeologic conditions very similar to the proposed geological repository at Yucca Mountain. This body of data is complemented by laboratory transport studies and a synthesis of recent modeling investigations from the NTS, with an emphasis on the ongoing Yucca Mountain Program (YMP) efforts. Overall, understanding the controls of radionuclide mobility associated with these nuclear tests will provide insight into the repository's future performance as well as bounds and calibrations for the numerical predictions of long-term radionuclide releases and migration.

  9. Fast analysis of radionuclide decay chain migration

    NASA Astrophysics Data System (ADS)

    Chen, J. S.; Liang, C. P.; Liu, C. W.; Li, L.

    2014-12-01

    A novel tool for rapidly predicting the long-term plume behavior of an arbitrary length radionuclide decay chain is presented in this study. This fast tool is achieved based on generalized analytical solutions in compact format derived for a set of two-dimensional advection-dispersion equations coupled with sequential first-order decay reactions in groundwater system. The performance of the developed tool is evaluated by a numerical model using a Laplace transform finite difference scheme. The results of performance evaluation indicate that the developed model is robust and accurate. The developed model is then used to fast understand the transport behavior of a four-member radionuclide decay chain. Results show that the plume extents and concentration levels of any target radionuclide are very sensitive to longitudinal, transverse dispersion, decay rate constant and retardation factor. The developed model are useful tools for rapidly assessing the ecological and environmental impact of the accidental radionuclide releases such as the Fukushima nuclear disaster where multiple radionuclides leaked through the reactor, subsequently contaminating the local groundwater and ocean seawater in the vicinity of the nuclear plant.

  10. Fuel-mix, fuel efficiency, and transport demand affect prospects for biofuels in northern Europe.

    PubMed

    Bright, Ryan M; Strømman, Anders Hammer

    2010-04-01

    Rising greenhouse gas (GHG) emissions in the road transport sector represents a difficult mitigation challenge due to a multitude of intricate factors, namely the dependency on liquid energy carriers and infrastructure lock-in. For this reason, low-carbon renewable energy carriers, particularly second generation biofuels, are often seen as a prominent candidate for realizing reduced emissions and lowered oil dependency over the medium- and long-term horizons. However, the overarching question is whether advanced biofuels can be an environmentally effective mitigation strategy in the face of increasing consumption and resource constraints. Here we develop both biofuel production and road transport consumption scenarios for northern Europe-a region with a vast surplus of forest bioenergy resources-to assess the potential role that forest-based biofuels may play over the medium- and long-term time horizons using an environmentally extended, multiregion input-output model. Through scenarios, we explore how evolving vehicle technologies and consumption patterns will affect the mitigation opportunities afforded by any future supply of forest biofuels. We find that in a scenario involving ambitious biofuel targets, the size of the GHG mitigation wedge attributed to the market supply of biofuels is severely reduced under business-as-usual growth in consumption in the road transport sector. Our results indicate that climate policies targeting the road transport sector which give high emphases to reducing demand (volume), accelerating the deployment of more fuel-efficient vehicles, and promoting altered consumption patterns (structure) can be significantly more effective than those with single emphasis on expanded biofuel supply.

  11. Task 3: PNNL Visit by JAEA Researchers to Participate in TODAM Code Applications to Fukushima Rivers and to Evaluate the Feasibility of Adaptation of FLESCOT Code to Simulate Radionuclide Transport in the Pacific Ocean Coastal Water Around Fukushima

    SciTech Connect

    Onishi, Yasuo

    2013-03-29

    Four JAEA researchers visited PNNL for two weeks in February, 2013 to learn the PNNL-developed, unsteady, one-dimensional, river model, TODAM and the PNNL-developed, time-dependent, three dimensional, coastal water model, FLESCOT. These codes predict sediment and contaminant concentrations by accounting sediment-radionuclide interactions, e.g., adsorption/desorption and transport-deposition-resuspension of sediment-sorbed radionuclides. The objective of the river and coastal water modeling is to simulate • 134Cs and 137Cs migration in Fukushima rivers and the coastal water, and • their accumulation in the river and ocean bed along the Fukushima coast. Forecasting the future cesium behavior in the river and coastal water under various scenarios would enable JAEA to assess the effectiveness of various on-land remediation activities and if required, possible river and coastal water clean-up operations to reduce the contamination of the river and coastal water, agricultural products, fish and other aquatic biota. PNNL presented the following during the JAEA visit to PNNL: • TODAM and FLESCOT’s theories and mathematical formulations • TODAM and FLESCOT model structures • Past TODAM and FLESCOT applications • Demonstrating these two codes' capabilities by applying them to simple hypothetical river and coastal water cases. • Initial application of TODAM to the Ukedo River in Fukushima and JAEA researchers' participation in its modeling. PNNL also presented the relevant topics relevant to Fukushima environmental assessment and remediation, including • PNNL molecular modeling and EMSL computer facilities • Cesium adsorption/desorption characteristics • Experiences of connecting molecular science research results to macro model applications to the environment • EMSL tour • Hanford Site road tour. PNNL and JAEA also developed future course of actions for joint research projects on the Fukushima environmental and remediation assessments.

  12. Migration of conservative and sorbing radionuclides in heterogeneous fractured rock aquifers at the Nevada Test Site

    NASA Astrophysics Data System (ADS)

    Boryta, J. R.; Wolfsberg, A. V.

    2003-12-01

    The Nevada Test Site (NTS) is the United States continental nuclear weapons testing site. The larger underground tests, including BENHAM and TYBO, were conducted at Pahute Mesa. The BENHAM test, conducted in 1968, was detonated 1.4 km below the surface and the TYBO test, conducted in 1975, was detonated at a depth of 765 m. Between 1996 and 1998, several radionuclides were discovered in trace concentrations in a monitoring well complex 273 m from TYBO and 1300 m from BENHAM. Previous studies associated with these measurements have focused primarily on a) plutonium discovered in the observation wells, which was identified through isotopic finger printing as originating at BENHAM, b) colloid-facilitated plutonium transport processes, and c) vertical convection in subsurface nuclear test collapse chimneys. In addition to plutonium, several other non-, weakly-, and strongly-sorbing radionuclides were discovered in trace concentrations in the observation wells, including tritium, carbon-14, chlorine-36, iodine-129, technetium-99, neptunium-237, strontium-90, cesium-137, americium-241, and europium-152,154,155. The range in retardation processes affecting these different radionuclides provides additional information for assessing groundwater solute transport model formulations. For all radionuclides, simulation results are most sensitive to the fracture porosity and fracture aperture. Additionally, for weakly sorbing Np, simulation results are highly sensitive to the matrix sorption coefficient. For strongly sorbing species, migration in the absence of colloids can only be simulated if fracture apertures are set very large, reducing the amount of diffusion that can occur. For these species, colloid-facilitated transport appears to be a more likely explanation for the measurements. This is corroborated with colloid-transport model simulations.

  13. Quantifying particulate and colloidal release of radionuclides in waste-weathered hanford sediments.

    PubMed

    Perdrial, Nicolas; Thompson, Aaron; LaSharr, Kelsie; Amistadi, Mary Kay; Chorover, Jon

    2015-05-01

    At the Hanford Site in the state of Washington, leakage of hyperalkaline, high ionic strength wastewater from underground storage tanks into the vadose zone has induced mineral transformations and changes in radionuclide speciation. Remediation of this wastewater will decrease the ionic strength of water infiltrating to the vadose zone and could affect the fate of the radionuclides. Although it was shown that radionuclide host phases are thermodynamically stable in the presence of waste fluids, a decrease in solution ionic strength and pH could alter aggregate stability and remobilize radionuclide-bearing colloids and particulate matter. We quantified the release of particulate, colloidal, and truly dissolved Sr, Cs, and I from hyperalkaline-weathered Hanford sediments during a low ionic strength pore water leach and characterized the released particles and colloids using electron microscopy and X-ray diffraction. Although most of the Sr, Cs, and I was released in dissolved form, between 3 and 30% of the Sr and 4 to 18% of the Cs was associated with a dominantly zeolitic mobile particulate fraction. Thus, the removal of hyperalkaline wastewater will likely induce Sr and Cs mobilization that will be augmented by particulate- and colloid-facilitated transport.

  14. Ground transport stress affects bacteria in the rumen of beef cattle: A real-time PCR analysis.

    PubMed

    Deng, Lixin; He, Cong; Zhou, Yanwei; Xu, Lifan; Xiong, Huijun

    2016-10-03

    Transport stress syndrome often appears in beef cattle during ground transportation, leading to changes in their capacity to digest food due to changes in rumen microbiota. The present study aimed to analyze bacteria before and after cattle transport. Eight Xianan beef cattle were transported over 1000 km. Rumen fluid and blood were sampled before and after transport. Real-time PCR was used to quantify rumen bacteria. Cortisol and adrenocorticotrophic hormone (ACTH) were measured. Cortisol and ACTH were increased on day 1 after transportation and decreased by day 3. Cellulolytic bacteria (Fibrobacter succinogenes and Ruminococcus flavefaciens), Ruminococcus amylophilus and Prevotella albensis were increased at 6 h and declined by 15 days after transport. There was a significant reduction in Succinivibrio dextrinosolvens, Prevotella bryantii, Prevotella ruminicola and Anaerovibrio lipolytica after transport. Rumen concentration of acetic acid increased after transport, while rumen pH and concentrations of propionic and butyric acids were decreased. Body weight decreased by 3 days and increased by 15 days after transportation. Using real-time PCR analysis, we detected changes in bacteria in the rumen of beef cattle after transport, which might affect the growth of cattle after transport.

  15. Quantitative modeling of Cerenkov light production efficiency from medical radionuclides.

    PubMed

    Beattie, Bradley J; Thorek, Daniel L J; Schmidtlein, Charles R; Pentlow, Keith S; Humm, John L; Hielscher, Andreas H

    2012-01-01

    There has been recent and growing interest in applying Cerenkov radiation (CR) for biological applications. Knowledge of the production efficiency and other characteristics of the CR produced by various radionuclides would help in accessing the feasibility of proposed applications and guide the choice of radionuclides. To generate this information we developed models of CR production efficiency based on the Frank-Tamm equation and models of CR distribution based on Monte-Carlo simulations of photon and β particle transport. All models were validated against direct measurements using multiple radionuclides and then applied to a number of radionuclides commonly used in biomedical applications. We show that two radionuclides, Ac-225 and In-111, which have been reported to produce CR in water, do not in fact produce CR directly. We also propose a simple means of using this information to calibrate high sensitivity luminescence imaging systems and show evidence suggesting that this calibration may be more accurate than methods in routine current use.

  16. Geochronological reconstruction of 137Cs transport from the Coruh river to the SE Black Sea: comparative assessment of radionuclide retention in the mountainous catchment area

    NASA Astrophysics Data System (ADS)

    Gulin, S. B.; Polikarpov, G. G.; Martin, J.-M.

    2003-11-01

    The deposition record of 137Cs was traced in the SE Black Sea sediments adjacent to the Coruh river mouth in comparison with the earlier studied chronology of 137Cs deposition in front of the Danube delta (NW Black Sea). In both cases, the 137Cs profiles showed two subsurface peaks attributable to maximum fallout of 'bomb' and Chernobyl radionuclides. The Coruh profile revealed a larger contribution of 'bomb' 137Cs in comparison with the Chernobyl input, suggesting different coverage of NW and SE Black Sea regions with the Chernobyl fallout. The 137Cs-derived dating showed that maximum deposition of particulate bound 137Cs in sediments adjacent to the Coruh river mouth was delayed for ˜14 yr relative to date of Chernobyl accident, reflecting a buffer effect of the watershed soils. This transit time is 3 times longer than in the Danube catchment area, indicating a difference in retention processes in these mountainous (Coruh) and lowland (Danube) river basins. The 137Cs profile in Coruh sediments showed penetration of 137Cs to much greater depth than would be expected from 137Cs fallout chronology, suggesting the sediment mixing rate of 1.3 cm 2 yr -1. This value was used to evaluate deposition chronology of 137Cs, applying the model developed for pulse fallout case. Comparing the measured and modelled data has allowed differentiation of the flood-induced discharge of the 137Cs-containing suspended matter and the slower transit of eroded soil particles from the contaminated catchment areas. The obtained results may be used for the prediction of period when the pollutants, deposited over the river basins, can reach the Black Sea.

  17. Accumulation of radionuclides in selected marine biota from Manjung coastal area

    SciTech Connect

    Abdullah, Anisa Hamzah, Zaini; Wood, Ab. Khalik; Saat, Ahmad; Alias, Masitah

    2015-04-29

    Distribution of radionuclides from anthropogenic activities has been intensively studied due to the accumulation of radionuclides in marine ecosystem. Manjung area is affected by rapid population growth and socio-economic development such as heavy industrial activities including coal fired power plant, iron foundries, port development and factories, agricultural runoff, waste and toxic discharge from factories.It has radiological risk and toxic effect when effluent from the industries in the area containing radioactive materials either being transported to the atmosphere and deposited back over the land or by run off to the river and flow into coastal area and being absorbed by marine biota. Radionuclides presence in the marine ecosystem can be adversely affect human health when it enters the food chain. This study is focusing on the radionuclides [thorium (Th), uranium (U), radium-226 ({sup 226}Ra), radium-228 ({sup 228}Ra) and potassium-40 ({sup 40}K)] content in marine biota and sea water from Manjung coastal area. Five species of marine biota including Johnius dussumieri (Ikan Gelama), Pseudorhombus malayanus (Ikan Sebelah), Arius maculatus (Ikan Duri), Portunus pelagicus (Ketam Renjong) and Charybdis natator (Ketam Salib) were collected during rainy and dry seasons. Measurements were carried out using Inductively Coupled Plasma Mass Spectrometer (ICPMS). The results show that the concentration of radionuclides varies depends on ecological environment of respective marine biota species. The concentrations and activity concentrations are used for the assessment of potential internal hazard index (H{sub in}), transfer factor (TF), ingestion dose rate (D) and health risk index (HRI) to monitor radiological risk for human consumption.

  18. Radionuclide Retention in Concrete Waste Forms

    SciTech Connect

    Mattigod, Shas V.; Bovaird, Chase C.; Wellman, Dawn M.; Wood, Marcus I.

    2010-09-30

    Assessing long-term performance of Category 3 waste cement grouts for radionuclide encasement requires knowledge of the radionuclide-cement interactions and mechanisms of retention (i.e., sorption or precipitation); the mechanism of contaminant release; the significance of contaminant release pathways; how waste form performance is affected by the full range of environmental conditions within the disposal facility; the process of waste form aging under conditions that are representative of processes occurring in response to changing environmental conditions within the disposal facility; the effect of waste form aging on chemical, physical, and radiological properties; and the associated impact on contaminant release. This knowledge will enable accurate prediction of radionuclide fate when the waste forms come in contact with groundwater. The information presented in the report provides data that 1) quantify radionuclide retention within concrete waste form materials similar to those used to encapsulate waste in the Low-Level Waste Burial Grounds (LLBG); 2) measure the effect of concrete waste form properties likely to influence radionuclide migration; and 3) quantify the stability of uranium-bearing solid phases of limited solubility in concrete.

  19. Event-based stormwater quality and quantity loadings from elevated urban infrastructure affected by transportation.

    PubMed

    Sansalone, John J; Hird, Jonathan P; Cartledge, Frank K; Tittlebaum, Marty E

    2005-01-01

    Urban-rainfall runoff affected by transportation is a complex matrix of a very wide gradation of particulate matter (< 1 to > 10 000 microm) and dissolved inorganic and organic constituents. Particulate matter transported by rainfall runoff can be a significant vector for many reactive particulate-bound constituents, particularly metal elements. The water quality and hydrology of nine events from a representative elevated section of Interstate 10 (I-10) (eastbound average daily traffic load of 70 400 vehicles) in Baton Rouge, Louisiana, were characterized and compared with respect to the passage of each hydrograph. Residence time on the paved concrete surface was less than 30 minutes for all events. Results indicate that event-mean concentrations (EMCs) of particulate matter as total-suspended solids (TSS) (138 to 561 mg/L) and chemical-oxygen demand (COD) (128 to 1440 mg/L) were greater than those found in untreated municipal wastewater from the same service area. Particulate-matter dissolution and COD partitioned as a function of pH, pavement residence time, and organic content. In general, delivery of mass for aggregate indices, such as particulate matter (measured as TSS) and COD mass, were driven by the hydrology of the event, while concentrations of aggregate-constituent measurements, such as total-dissolved solids (TDS), illustrated an exponential-type decline during the rising limb of the hydrograph. Despite the short residence times, wide solids gradation, partitioning, and complexity of the rainfall-runoff chemistry, conductivity and dissolved solids were strongly correlated. Characterization of the transport and loads of constituents in urban-rainfall runoff, as a function of hydrology, is a necessary first step when considering treatability, structural or nonstructural controls, and mass trading for discharges from paved infrastructure.

  20. Exploring Factors Affecting Emergency Medical Services Staffs' Decision about Transporting Medical Patients to Medical Facilities

    PubMed Central

    Seyedin, Hesam; Jamshidi-Orak, Roohangiz

    2014-01-01

    Transfer of patients in medical emergency situations is one of the most important missions of emergency medical service (EMS) staffs. So this study was performed to explore affecting factors in EMS staffs' decision during transporting of patients in medical situations to medical facilities. The participants in this qualitative study consisted of 18 EMS staffs working in prehospital care facilities in Tehran, Iran. Data were gathered through semistructured interviews. The data were analyzed using a content analysis approach. The data analysis revealed the following theme: “degree of perceived risk in EMS staffs and their patients.” This theme consisted of two main categories: (1) patient's condition' and (2) the context of the EMS mission'. The patent's condition category emerged from “physical health statuses,” “socioeconomic statuses,” and “cultural background” subcategories. The context of the EMS mission also emerged from two subcategories of “characteristics of the mission” and EMS staffs characteristics'. EMS system managers can consider adequate technical, informational, financial, educational, and emotional supports to facilitate the decision making of their staffs. Also, development of an effective and user-friendly checklist and scoring system was recommended for quick and easy recognition of patients' needs for transportation in a prehospital situation. PMID:24891953

  1. Exploring Factors Affecting Emergency Medical Services Staffs' Decision about Transporting Medical Patients to Medical Facilities.

    PubMed

    Ebrahimian, Abbasali; Seyedin, Hesam; Jamshidi-Orak, Roohangiz; Masoumi, Gholamreza

    2014-01-01

    Transfer of patients in medical emergency situations is one of the most important missions of emergency medical service (EMS) staffs. So this study was performed to explore affecting factors in EMS staffs' decision during transporting of patients in medical situations to medical facilities. The participants in this qualitative study consisted of 18 EMS staffs working in prehospital care facilities in Tehran, Iran. Data were gathered through semistructured interviews. The data were analyzed using a content analysis approach. The data analysis revealed the following theme: "degree of perceived risk in EMS staffs and their patients." This theme consisted of two main categories: (1) patient's condition' and (2) the context of the EMS mission'. The patent's condition category emerged from "physical health statuses," "socioeconomic statuses," and "cultural background" subcategories. The context of the EMS mission also emerged from two subcategories of "characteristics of the mission" and EMS staffs characteristics'. EMS system managers can consider adequate technical, informational, financial, educational, and emotional supports to facilitate the decision making of their staffs. Also, development of an effective and user-friendly checklist and scoring system was recommended for quick and easy recognition of patients' needs for transportation in a prehospital situation.

  2. Factors affecting pesticide occurrence and transport in a large Midwestern river basin

    USGS Publications Warehouse

    Crawford, Charles G.

    2001-01-01

    Several factors affect the occurrence and transport of pesticides in surface waters of the 29,400 km2 White River Basin in Indiana. A relationship was found between pesticide use and the average annual concentration of that pesticide in the White River, although this relationship varies for different classes of pesticides. About one percent of the mass applied of each of the commonly used agricultural herbicides was transported from the basin via the White River. Peak pesticide concentrations were typically highest in late spring or early summer and were associated with periods of runoff following application. Concentrations of diazinon were higher in an urban basin than in two agricultural basins, corresponding to the common use of this insecticide on lawns and gardens in urban areas. Concentrations of atrazine, a corn herbicide widely used in the White River Basin, were higher in an agricultural basin with permeable, well-drained soils, than in an agricultural basin with less permeable, more poorly drained soils. Although use of butylate and cyanazine was comparable in the White River Basin between 1992 and 1994, concentrations in the White River of butylate, which is incorporated into soil, were substantially less than for cyanazine, which is typically applied to the soil surface.

  3. Radionuclide studies in impotence

    SciTech Connect

    Hilson, A.J.; Lewis, C.A. )

    1991-04-01

    Impotence may be of physiological origin with causes including vascular or neurological pathology. Alternatively, it may be of psychogenic origin. Clinicians can distinguish between psychological and organic impotence by observing nocturnal penile tumescence. Non-radionuclide investigations for organic impotence include penile plethysmography or pulse Doppler analysis for arterial supply, cavernosometry for venous drainage, and biothesiometry or evoked potentials for neurological pathology. Radionuclide studies are primarily based on the use of technetium 99m-pertechnetate, 99mTc-red blood cells, or xenon 133 to study the blood flow, with or without pharmacological intervention, commonly papaverine. 26 references.

  4. Surface Complexation Modeling of Radionuclide Sorption in the Saturated Zone of Yucca Mountain Rocks

    NASA Astrophysics Data System (ADS)

    Ding, M.; Kelkar, S.; Fabryka-Martin, J. T.; Caporuscio, F. A.; Meijer, A.

    2008-12-01

    The U.S. DOE is preparing to submit a license application to the Nuclear Regulatory Commission (NRC) to create a geologic repository at the Yucca Mountain, Nevada, for the disposal of spent nuclear fuel and high- level radioactive waste. In the event of a radionuclide release, the ground water beneath the Yucca Mountain is the primary medium through which most radionuclides might move from the geologic repository to the accessible environment. Sorption of radionuclides onto rock surfaces is one of the important processes affecting the transport in the saturated zone of Yucca Mountain (SZ). For this reason, a considerable experimental effort has been devoted over the last two decades to the measurements of sorption distribution coefficients (Kd) for various radionuclides in rock samples from the vicinity of the repository site at the Yucca Mountain. Despite the quantity and quality of the data, they are strictly valid only under the experimental conditions at which they were measured, whereas the Kd distributions used as inputs in performance assessment calculations need to represent the range of geochemical conditions and rock types expected to occur along the transport pathways. Hence geochemical modeling was used to calculate and predict chemical speciation of elements of interest in solid and solution under a variety of different conditions. The computer code PHREEQC v2.3 and the thermodynamic database PHREEQCDATA025.DAT were used for this geochemical modeling. The modeling provides a basis for extrapolating the experimentally derived Kd's, and provides improved understanding of the underlying sorption mechanisms, thus justifying and defending the Kd's selected for further radionuclide transport modeling development. This presentation focuses on the elements Am, U, Np and Pu which sorb in the SZ primarily via surface complexation reactions. We discuss quantitatively the influence of groundwater compositions, rock surface area, binding constants, and

  5. Switch-Loop Flexibility Affects Transport of Large Drugs by the Promiscuous AcrB Multidrug Efflux Transporter

    PubMed Central

    Cha, Hi-jea; Müller, Reinke T.

    2014-01-01

    Multidrug efflux transporters recognize a variety of structurally unrelated compounds for which the molecular basis is poorly understood. For the resistance nodulation and cell division (RND) inner membrane component AcrB of the AcrAB-TolC multidrug efflux system from Escherichia coli, drug binding occurs at the access and deep binding pockets. These two binding areas are separated by an 11-amino-acid-residue-containing switch loop whose conformational flexibility is speculated to be essential for drug binding and transport. A G616N substitution in the switch loop has a distinct and local effect on the orientation of the loop and on the ability to transport larger drugs. Here, we report a distinct phenotypical pattern of drug recognition and transport for the G616N variant, indicating that drug substrates with minimal projection areas of >70 Å2 are less well transported than other substrates. PMID:24914123

  6. Monitoring suspended sediment transport in an ice-affected river using acoustic Doppler current profilers

    NASA Astrophysics Data System (ADS)

    Moore, S. A.; Ghareh Aghaji Zare, S.; Rennie, C. D.; Ahmari, H.; Seidou, O.

    2013-12-01

    Quantifying sediment budgets and understanding the processes which control fluvial sediment transport is paramount to monitoring river geomorphology and ecological habitat. In regions that are subject to freezing there is the added complexity of ice. River ice processes impact flow distribution, water stage and sediment transport. Ice processes typically have the largest impact on sediment transport and channel morphodynamics when ice jams occur during ice cover formation and breakup. Ice jams may restrict flow and cause local acceleration when released. Additionally, ice can mechanically scour river bed and banks. Under-ice sediment transport measurements are lacking due to obvious safety and logistical reasons, in addition to a lack of adequate measurement techniques. Since some rivers can be covered in ice during six months of the year, the lack of data in winter months leads to large uncertainty in annual sediment load calculations. To address this problem, acoustic profilers are being used to monitor flow velocity, suspended sediment and ice processes in the Lower Nelson River, Manitoba, Canada. Acoustic profilers are ideal for under-ice sediment flux measurements since they can be operated autonomously and continuously, they do not disturb the flow in the zone of measurement and acoustic backscatter can be related to sediment size and concentration. In March 2012 two upward-facing profilers (1200 kHz acoustic Doppler current profiler, 546 KHz acoustic backscatter profiler) were installed through a hole in the ice on the Nelson River, 50 km downstream of the Limestone Generating Station. Data were recorded for four months, including both stable cover and breakup periods. This paper presents suspended sediment fluxes calculated from the acoustic measurements. Velocity data were used to infer the vertical distribution of sediment sizes and concentrations; this information was then used in the interpretation of the backscattered intensity data. It was found that

  7. Dopamine Transporter Gene Variant Affecting Expression in Human Brain is Associated with Bipolar Disorder

    PubMed Central

    Pinsonneault, Julia K; Han, Dawn D; Burdick, Katherine E; Kataki, Maria; Bertolino, Alessandro; Malhotra, Anil K; Gu, Howard H; Sadee, Wolfgang

    2011-01-01

    The gene encoding the dopamine transporter (DAT) has been implicated in CNS disorders, but the responsible polymorphisms remain uncertain. To search for regulatory polymorphisms, we measured allelic DAT mRNA expression in substantia nigra of human autopsy brain tissues, using two marker SNPs (rs6347 in exon 9 and rs27072 in the 3′-UTR). Allelic mRNA expression imbalance (AEI), an indicator of cis-acting regulatory polymorphisms, was observed in all tissues heterozygous for either of the two marker SNPs. SNP scanning of the DAT locus with AEI ratios as the phenotype, followed by in vitro molecular genetics studies, demonstrated that rs27072 C>T affects mRNA expression and translation. Expression of the minor T allele was dynamically regulated in transfected cell cultures, possibly involving microRNA interactions. Both rs6347 and rs3836790 (intron8 5/6 VNTR) also seemed to affect DAT expression, but not the commonly tested 9/10 VNTR in the 3′UTR (rs28363170). All four polymorphisms (rs6347, intron8 5/6 VNTR, rs27072 and 3′UTR 9/10 VNTR) were genotyped in clinical cohorts, representing schizophrenia, bipolar disorder, depression, and controls. Only rs27072 was significantly associated with bipolar disorder (OR=2.1, p=0.03). This result was replicated in a second bipolar/control population (OR=1.65, p=0.01), supporting a critical role for DAT regulation in bipolar disorder. PMID:21525861

  8. SRNL RADIONUCLIDE FIELD LYSIMETER EXPERIMENT: BASELINE CONSTRUCTION AND IMPLEMENTATION

    SciTech Connect

    Roberts, K.; Kaplan, D.; Bagwell, L.; Powell, B.; Almond, P.; Emerson, H.; Hixon, A.; Jablonski, J.; Buchanan, C.; Waterhouse, T.

    2012-10-17

    The purpose of this document is to compile information regarding experimental design, facility design, construction, radionuclide source preparation, and path forward for the ten year Savannah River National Laboratory (SRNL) Radionuclide Field Lysimeter Experiment at the Savannah River Site (SRS). This is a collaborative effort by researchers at SRNL and Clemson University. The scientific objectives of this study are to: Study long-term radionuclide transport under conditions more representative of vadose zone conditions than laboratory experiments; Provide more realistic quantification of radionuclide transport and geochemistry in the vadose zone, providing better information pertinent to radioactive waste storage solutions than presently exists; Reduce uncertainty and improve justification for geochemical models such as those used in performance assessments and composite analyses.

  9. Understanding how hydrodynamics affects particle transport in saturated fractures using modelling and experimental results

    NASA Astrophysics Data System (ADS)

    Cianflone, S.; Lakhian, V.; Dickson, S. E.

    2013-12-01

    Approximately 35% of Canadians and Americans utilize groundwater for drinking water and as such, it is essential to understand the mechanisms which may jeopardize this resource. Porous media aquifers typically provide significant removal of particulate contaminants (eg. viruses, bacteria); however, fractures in fractured rock aquifers and aquitards often provide pathways for particles to move in greater numbers and speed than in porous media. Thus, understanding flow and transport in fractures is important for the preservation and use of groundwater sources. Models based on coupling flow and transport equations can be used in understanding transport in fractures. Both experiments and simulations have shown that there are inconsistencies in current transport, attachment and detachment theory, particularly when particle size is varied. The assumption that hydrodynamic effects do not significantly affect transport of particles is likely untrue. As well, it has been shown that preferential flow paths occur in fractures, but the effects of path specific properties such as fracture geometry have yet to be thoroughly explored. It has been observed that eddies caused by local changes in geometry exist in fractures in the environment and models have demonstrated that such eddies will retard the flow of particles. In this work, two 2D fractures were randomly generated with a mean aperture of approximately 2mm. Finite element software, COMSOL Multiphysics, generated flow fields through the fractures by numerically solving the steady-state Navier-Stokes equation for varied flow rates. Eddies were observed in one of the fractures at both low (~1 m/day) and high (>100 m/day) velocities. A program was written using random walk particle tracking to simulate transport. Theories of attachment, detachment and matrix flow are not included in this model in order to isolate hydrodynamic forces. In combination with the modelling procedure, the two fractures were inscribed into pieces of

  10. Gallbladder radionuclide scan

    MedlinePlus

    ... please enable JavaScript. Gallbladder radionuclide scan is a test that uses radioactive material to check gallbladder function. It is also used ... for bile duct blockage or leak. How the Test is Performed ... called a gamma emitting tracer into a vein. This material collects mostly in the liver. It will then ...

  11. Establishing equivalence for activity standards of short-lived radionuclides using the NPL secondary standard radionuclide calibrator.

    PubMed

    Woods, M J; Baker, M

    2004-01-01

    Conventional comparison techniques used between National Metrology Institutes are not practicable for short-lived radionuclides because of geographical separations and transport difficulties. The NPL Secondary Standard Radionuclide Calibrator provides an alternative approach and a comparison was conducted with 18F to investigate its feasibility. The exercise was successful and the paper details the protocol used, the quality assurance mechanisms introduced to underpin the comparison and an analysis of the results. It was also demonstrated that this approach could be linked to the BIPM SIR system. Recommendations are presented for the extension of this work to other suitable, short-lived radionuclides.

  12. Non-steroidal anti-inflammatory drugs affect the methotrexate transport in IEC-6 cells.

    PubMed

    Sosogi, Aiko; Gao, Feng; Tomimatsu, Takashi; Hirata, Koji; Horie, Toshiharu

    2003-06-13

    Methotrexate (MTX) is used not only for the cancer chemotherapy but also for the treatment of rheumatic disease, often together with non-steroidal anti-inflammatory drugs (NSAIDs). MTX is actively cotransported with H(+) in the small intestine, mediated by a reduced folate carrier (RFC). The coadministration of some NSAIDs with MTX to rats caused a decrease of MTX absorption through the small intestine. This may be due to the uncoupling effect of oxidative phosphorylation of the NSAIDs. The present study investigated whether flufenamic acid, diclofenac and indomethacin, NSAIDs, decreased ATP content of rat-derived intestinal epithelial cell line IEC-6 cells and affected the MTX transport in IEC-6 cells. The MTX uptake in IEC-6 cells was dependent on medium pH and maximum around pH 4.5-5.5. The MTX uptake was composed of a transport inhibited by 4, 4'-diisothiocyanostilbene-2, 2'-disulfonic acid (DIDS) and a non-saturable one. The DIDS-sensitive component in the MTX uptake showed a saturation kinetics (Michaelis-Menten constant (Km): 3.91 +/- 0.52 microM, Maximum velocity (Vmax): 94.66 +/- 6.56 pmol/mg protein/5 min). The cellular ATP content in IEC-6 cells decreased significantly at 30 min after the cells were started to incubate with the NSAIDs (250 microM flufenamic acid, 500 microM diclofenac and 500 microM indomethacin). The MTX uptake in IEC-6 cells in the presence of the NSAIDs decreased with the reduction of cellular ATP content and showed a good correlation with the ATP content (correlation coefficient: 0.982). Thus it seems likely that the ATP content in IEC-6 cells with the NSAIDs decreased due to the uncoupling effect of oxidative phosphorylation of the NSAIDs, resulting in the inhibition of the secondary active transport of MTX in IEC-6 cells. The present results also suggest that IEC-6 cells are useful to evaluate the drug interaction relating to this carrier system.

  13. Alpha-Synuclein affects neurite morphology, autophagy, vesicle transport and axonal degeneration in CNS neurons

    PubMed Central

    Koch, J C; Bitow, F; Haack, J; d'Hedouville, Z; Zhang, J-N; Tönges, L; Michel, U; Oliveira, L M A; Jovin, T M; Liman, J; Tatenhorst, L; Bähr, M; Lingor, P

    2015-01-01

    Many neuropathological and experimental studies suggest that the degeneration of dopaminergic terminals and axons precedes the demise of dopaminergic neurons in the substantia nigra, which finally results in the clinical symptoms of Parkinson disease (PD). The mechanisms underlying this early axonal degeneration are, however, still poorly understood. Here, we examined the effects of overexpression of human wildtype alpha-synuclein (αSyn-WT), a protein associated with PD, and its mutant variants αSyn-A30P and -A53T on neurite morphology and functional parameters in rat primary midbrain neurons (PMN). Moreover, axonal degeneration after overexpression of αSyn-WT and -A30P was analyzed by live imaging in the rat optic nerve in vivo. We found that overexpression of αSyn-WT and of its mutants A30P and A53T impaired neurite outgrowth of PMN and affected neurite branching assessed by Sholl analysis in a variant-dependent manner. Surprisingly, the number of primary neurites per neuron was increased in neurons transfected with αSyn. Axonal vesicle transport was examined by live imaging of PMN co-transfected with EGFP-labeled synaptophysin. Overexpression of all αSyn variants significantly decreased the number of motile vesicles and decelerated vesicle transport compared with control. Macroautophagic flux in PMN was enhanced by αSyn-WT and -A53T but not by αSyn-A30P. Correspondingly, colocalization of αSyn and the autophagy marker LC3 was reduced for αSyn-A30P compared with the other αSyn variants. The number of mitochondria colocalizing with LC3 as a marker for mitophagy did not differ among the groups. In the rat optic nerve, both αSyn-WT and -A30P accelerated kinetics of acute axonal degeneration following crush lesion as analyzed by in vivo live imaging. We conclude that αSyn overexpression impairs neurite outgrowth and augments axonal degeneration, whereas axonal vesicle transport and autophagy are severely altered. PMID:26158517

  14. Two-dimensional numerical simulation of geochemical transport in Yucca Mountain

    SciTech Connect

    Travis, B.J.; Nuttall, H.E.

    1987-12-01

    Several physical and chemical processes can affect transport of radionuclides in Yucca Mountain. Geometric spreading and lateral flow will reduce the concentration of contaminated water reaching the accessible environment. Travel times to the water table are calculated to be at least several tens of thousands of years. Colloid transport can also enhance radionuclide transport, but will be important only if fracture flow is. Finally, the heat load from repository waste can alter the distribution of some naturally occurring minerals. In particular, dissolution and precipitation of SiO{sub 2} should lead to a region of reduced permeability around waste canisters. 22 refs., 47 figs., 7 tabs.

  15. New best estimates for radionuclide solid-liquid distribution coefficients in soils. Part 3: miscellany of radionuclides (Cd, Co, Ni, Zn, I, Se, Sb, Pu, Am, and others).

    PubMed

    Gil-García, C; Tagami, K; Uchida, S; Rigol, A; Vidal, M

    2009-09-01

    New best estimates for the solid-liquid distribution coefficient (K(d)) for a set of radionuclides are proposed, based on a selective data search and subsequent calculation of geometric means. The K(d) best estimates are calculated for soils grouped according to the texture and organic matter content. For a limited number of radionuclides this is extended to consider soil cofactors affecting soil-radionuclide interaction, such as pH, organic matter content, and radionuclide chemical speciation. Correlations between main soil properties and radionuclide K(d) are examined to complete the information derived from the best estimates with a rough prediction of K(d) based on soil parameters. Although there are still gaps for many radionuclides, new data from recent studies improve the calculation of K(d) best estimates for a number of radionuclides, such as selenium, antimony, and iodine.

  16. Gibberellins inhibit adventitious rooting in hybrid aspen and Arabidopsis by affecting auxin transport.

    PubMed

    Mauriat, Mélanie; Petterle, Anna; Bellini, Catherine; Moritz, Thomas

    2014-05-01

    Knowledge of processes involved in adventitious rooting is important to improve both fundamental understanding of plant physiology and the propagation of numerous plants. Hybrid aspen (Populus tremula × tremuloïdes) plants overexpressing a key gibberellin (GA) biosynthesis gene (AtGA20ox1) grow rapidly but have poor rooting efficiency, which restricts their clonal propagation. Therefore, we investigated the molecular basis of adventitious rooting in Populus and the model plant Arabidopsis. The production of adventitious roots (ARs) in tree cuttings is initiated from the basal stem region, and involves the interplay of several endogenous and exogenous factors. The roles of several hormones in this process have been characterized, but the effects of GAs have not been fully investigated. Here, we show that a GA treatment negatively affects the numbers of ARs produced by wild-type hybrid aspen cuttings. Furthermore, both hybrid aspen plants and intact Arabidopsis seedlings overexpressing AtGA20ox1, PttGID1.1 or PttGID1.3 genes (with a 35S promoter) produce few ARs, although ARs develop from the basal stem region of hybrid aspen and the hypocotyl of Arabidopsis. In Arabidopsis, auxin and strigolactones are known to affect AR formation. Our data show that the inhibitory effect of GA treatment on adventitious rooting is not mediated by perturbation of the auxin signalling pathway, or of the strigolactone biosynthetic and signalling pathways. Instead, GAs appear to act by perturbing polar auxin transport, in particular auxin efflux in hybrid aspen, and both efflux and influx in Arabidopsis.

  17. Introduction to CRRIS: a computerized radiological risk investigation system for assessing atmospheric releases of radionuclides

    SciTech Connect

    Baes, C.F. III; Miller, C.W.; Kocher, D.C.; Sjoreen, A.L.; Murphy, B.D.

    1985-08-01

    The CRRIS is a Computerized Radiological Risk Investigation System consisting of eight fully integrated computer codes which calculate environmental transport of atmospheric releases of radionuclides and resulting doses and health risks to individuals or populations. Each code may also be used alone for various assessment applications. Radionuclides are handled by the CRRIS either in terms of the released radionuclides or the exposure radionuclides which consist of both the released nuclides and decay products that grow in during environmental transport. The CRRIS is not designed to simulate short-term effects. 51 refs.

  18. Transcription factor organic cation transporter 1 (OCT-1) affects the expression of porcine Klotho (KL) gene

    PubMed Central

    Zhou, Jiawei

    2016-01-01

    Klotho (KL), originally discovered as an aging suppressor, is a membrane protein that shares sequence similarity with the β-glucosidase enzymes. Recent reports showed Klotho might play a role in adipocyte maturation and systemic glucose metabolism. However, little is known about the transcription factors involved in regulating the expression of porcine KL gene. Deletion fragment analysis identified KL-D2 (−418 bp to −3 bp) as the porcine KL core promoter. MARC0022311SNP (A or G) in KL intron 1 was detected in Landrace × DIV pigs using the Porcine SNP60 BeadChip. The pGL-D2-A and pGL-D2-G were constructed with KL-D2 and the intron fragment of different alleles and relative luciferase activity of pGL3-D2-G was significantly higher than that of pGL3-D2-A in the PK cells and ST cells. This was possibly the result of a change in KL binding ability with transcription factor organic cation transporter 1 (OCT-1), which was confirmed using electrophoretic mobility shift assays (EMSA) and chromatin immune-precipitation (ChIP). Moreover, OCT-1 regulated endogenous KL expression by RNA interference experiments. Our study indicates SNP MARC0022311 affects porcine KL expression by regulating its promoter activity via OCT-1. PMID:27478698

  19. The addition of organic carbon and nitrate affects reactive transport of heavy metals in sandy aquifers.

    PubMed

    Satyawali, Yamini; Seuntjens, Piet; Van Roy, Sandra; Joris, Ingeborg; Vangeel, Silvia; Dejonghe, Winnie; Vanbroekhoven, Karolien

    2011-04-25

    Organic carbon introduction in the soil to initiate remedial measures, nitrate infiltration due to agricultural practices or sulphate intrusion owing to industrial usage can influence the redox conditions and pH, thus affecting the mobility of heavy metals in soil and groundwater. This study reports the fate of Zn and Cd in sandy aquifers under a variety of plausible in-situ redox conditions that were induced by introduction of carbon and various electron acceptors in column experiments. Up to 100% Zn and Cd removal (from the liquid phase) was observed in all the four columns, however the mechanisms were different. Metal removal in column K1 (containing sulphate), was attributed to biological sulphate reduction and subsequent metal precipitation (as sulphides). In the presence of both nitrate and sulphate (K2), the former dominated the process, precipitating the heavy metals as hydroxides and/or carbonates. In the presence of sulphate, nitrate and supplemental iron (Fe(OH)(3)) (K3), metal removal was also due to precipitation as hydroxides and/or carbonates. In abiotic column, K4, (with supplemental iron (Fe(OH)(3)), but no nitrate), cation exchange with soil led to metal removal. The results obtained were modeled using the reactive transport model PHREEQC-2 to elucidate governing processes and to evaluate scenarios of organic carbon, sulphate and nitrate inputs.

  20. Hyperosmotic and isosmotic shrinkage differentially affect protein phosphorylation and ion transport.

    PubMed

    Koltsova, Svetlana V; Akimova, Olga A; Kotelevtsev, Sergei V; Grygorczyk, Ryszard; Orlov, Sergei N

    2012-02-01

    In the present work, we compared the outcome of hyperosmotic and isosmotic shrinkage on ion transport and protein phosphorylation in C11-MDCK cells resembling intercalated cells from collecting ducts and in vascular smooth muscle cells (VSMC) from the rat aorta. Hyperosmotic shrinkage was triggered by cell exposure to hypertonic medium, whereas isosmotic shrinkage was evoked by cell transfer from an hypoosmotic to an isosmotic environment. Despite a similar cell volume decrease of 40%-50%, the consequences of hyperosmotic and isosmotic shrinkage on cellular functions were sharply different. In C11-MDCK and VSMC, hyperosmotic shrinkage completely inhibited Na(+),K(+)-ATPase and Na(+),P(i) cotransport. In contrast, in both types of cells isosmotic shrinkage slightly increased rather than suppressed Na(+),K(+)-ATPase and did not change Na(+),P(i) cotransport. In C11-MDCK cells, phosphorylation of JNK1/2 and Erk1/2 mitogen-activated protein kinases was augmented in hyperosmotically shrunken cells by ∼7- and 2-fold, respectively, but was not affected in cells subjected to isosmotic shrinkage. These results demonstrate that the data obtained in cells subjected to hyperosmotic shrinkage cannot be considered as sufficient proof implicating cell volume perturbations in the regulation of cellular functions under isosmotic conditions.

  1. Radionuclides in surface and groundwater

    USGS Publications Warehouse

    Campbell, Kate M.

    2009-01-01

    Unique among all the contaminants that adversely affect surface and water quality, radioactive compounds pose a double threat from both toxicity and damaging radiation. The extreme energy potential of many of these materials makes them both useful and toxic. The unique properties of radioactive materials make them invaluable for medical, weapons, and energy applications. However, mining, production, use, and disposal of these compounds provide potential pathways for their release into the environment, posing a risk to both humans and wildlife. This chapter discusses the sources, uses, and regulation of radioactive compounds in the United States, biogeochemical processes that control mobility in the environment, examples of radionuclide contamination, and current work related to contaminated site remediation.

  2. Osteoid osteoma: radionuclide diagnosis

    SciTech Connect

    Helms, C.A.; Hattner, R.S.; Vogler, J.B.

    1984-06-01

    The double-density sign, seen on radionuclide bone scans, is described for diagnosing osteoid osteomas and for localizing the nidus. Its use in differentiating the nidus of an osteoid osteoma from osteomyelitis is also described. The utility of computed tomography in localization of the nidus is also illustrated. The double-density sign was helpful in diagnosing seven cases of surgically confirmed osteoid osteoma.

  3. Rapid Migration of Radionuclides Leaked from High-Level Water Tanks; A Study of Salinity Gradients, Wetted Path Geometry and Water Vapor Transport

    SciTech Connect

    Anderson l. Ward; Glendon W. Gee; John S. Selker; Clay Cooper

    2002-04-24

    The basis of this study was the hypothesis that the physical and chemical properties of hypersaline tank waste could lead to wetting from instability and fingered flow following a tank leak. Thus, the goal of this project was to develop an understanding of the impacts of the properties of hypersaline fluids on transport through the unsaturated zone beneath Hanford's Tank Farms. There were three specific objectives (i) to develop an improved conceptualization of hypersaline fluid transport in laboratory (ii) to identify the degree to which field conditions mimic the flow processes observed in the laboratory and (iii) to provide a validation data set to establish the degree to which the conceptual models, embodied in a numerical simulator, could explain the observed field behavior. As hypothesized, high ionic strength solutions entering homogeneous pre-wetted porous media formed unstable wetting fronts atypical of low ionic strength infiltration. In the field, this mechanism could for ce flow in vertical flow paths, 5-15 cm in width, bypassing much of the media and leading to waste penetration to greater depths than would be predicted by current conceptual models. Preferential flow may lead to highly accelerated transport through large homogeneous units, and must be included in any conservative analysis of tank waste losses through coarse-textured units. However, numerical description of fingered flow using current techniques has been unreliable, thereby precluding tank-scale 3-D simulation of these processes. A new approach based on nonzero, hysteretic contract angles and fluid-dependent liquid entry has been developed for the continuum scale modeling of fingered flow. This approach has been coupled with and adaptive-grid finite-difference solver to permit the prediction of finger formation and persistence form sub centimeter scales to the filed scale using both scalar and vector processors. Although laboratory experiments demonstrated that elevated surface tens ion

  4. Rapid Migration of Radionuclides Leaked from High-Level Water Tanks: A Study of Salinity Gradients, Wetted Path Geometry and Water Vapor Transport

    SciTech Connect

    Anderson L. Ward; Glendon W. Gee; John S. Selker; Caly Cooper

    2002-04-24

    The basis of this study was the hypothesis that the physical and chemical properties of hypersaline tank waste could lead to wetting from instability and fingered flow following a tank leak. Thus, the goal of this project was to develop an understanding of the impacts of the properties of hypersaline fluids on transport through the unsaturated zone beneath Hanford's Tank Farms. There were three specific objectives (i) to develop an improved conceptualization of hypersaline fluid transport in laboratory (ii) to identify the degree to which field conditions mimic the flow processes observed in the laboratory and (iii) to provide a validation data set to establish the degree to which the conceptual models, embodied in a numerical simulator, could explain the observed field behavior. As hypothesized, high ionic strength solutions entering homogeneous pre-wetted porous media formed unstable wetting fronts a typical of low ionic strength infiltration. In the field, this mechanism could force flow in vertical flow paths, 5-15 cm in width, bypassing much of the media and leading to waste penetration to greater depths than would be predicted by current conceptual models. Preferential flow may lead to highly accelerated transport through large homogeneous units, and must be included in any conservative analysis of tank waste losses through coarse-textured units. However, numerical description of fingered flow using current techniques has been unreliable, thereby precluding tank-scale 3-D simulation of these processes. A new approach based on nonzero, hysteretic contact angles and fluid-dependent liquid entry has been developed for the continuum scale modeling of fingered flow. This approach has been coupled with and adaptive-grid finite-difference solver to permit the prediction of finger formation and persistence form sub centimeter scales to the filed scale using both scalar and vector processors. Although laboratory experiments demonstrated that elevated surface tension

  5. "Who's been feeding in my bed?" Benthivorous fish affect fluvial sediment transport - fact or fairy tale?

    NASA Astrophysics Data System (ADS)

    Rice, Stephen; Pledger, Andrew; Smith, James; Toone, Julia

    2016-04-01

    Many species of fish are benthivorous - they forage for food in the river bed - and their foraging disturbs, displaces and sorts bed materials with implications for fluvial sediment transport. Flume experiments have confirmed that benthic foraging by Barbel (Barbus barbus (L.)) and Chub (Squalius cephalus (L.)) modifies the structure and topography of water-worked gravels, thereby increasing particle entrainment probabilities and the quantity of sediment mobilised during experimental high flows. Field experiments and observations have demonstrated the impact of foraging on patch-scale bed disturbance, gravel structure, grain displacements and grain-size sorting. Initial ex-situ experiments support the suggestion that in low gradient rivers, shoals of fish like Bream (Abramis brama (L.)) entrain fine bed sediments, adding a biotic surcharge to the suspended sediment flux and modifying bed topography. These results underpin a novel proposal: that there is an aggregate, cumulative effect of benthic foraging on fluvial sediment transport at larger scales, including at scales where the contribution to sediment movement and river channel behaviour generates management concerns. Evaluating this proposal is a long-term goal, which is based on two intermediate objectives: to develop deeper mechanistic understanding of foraging impacts and to establish the spatial and temporal extent of geomorphologically significant feeding behaviours in river systems. The latter is crucial because field data are currently limited to a single reach on one UK river. It is reasonable to hypothesise that foraging impacts are spatially and temporally widespread because obligate and opportunistic benthic feeding is common and fish feed throughout their life. However, the effectiveness of foraging as a geomorphological process is likely to vary with factors including substrate size, fish community composition, food availability, water temperature, river flows and seasonal changes in fish

  6. Influences of Flow Transients and Porous Medium Heterogeneity on Colloid-Associated Contaminant Transport in the Vadose Zone

    SciTech Connect

    James Saiers; Joseph Ryan

    2006-07-02

    Radionuclides, metals, and dense non-aqueous phase liquids have contaminated about six billion cubic meters of soil at Department of Energy (DOE) sites. The subsurface transport of many of these contaminants is facilitated by colloids (i.e., microscopic, waterborne particles). The first step in the transport of contaminants from their sources to off-site surface water and groundwater is migration through the vadose zone. Developing our understanding of the migration of colloids and colloid-associated contaminants through the vadose zone is critical to assessing and controlling the release of contaminants from DOE sites. In this study, we examined the mobilization, transport, and filtration (retention) of mineral colloids and colloidassociated radionuclides within unsaturated porous media. This investigation involved laboratory column experiments designed to identify properties that affect colloid mobilization and retention and pore-scale visualization experiments designed to elucidate mechanisms that govern these colloid-mass transfer processes. The experiments on colloid mobilization and retention were supplemented with experiments on radionuclide transport through porous media and on radionuclide adsorption to mineral colloids. Observations from all of these experiments – the column and visualization experiments with colloids and the experiments with radionuclides – were used to guide the development of mathematical models appropriate for describing colloids and colloid-facilitated radionuclide transport through the vadose zone.

  7. Transport and Sorting of the Solanum tuberosum Sucrose Transporter SUT1 Is Affected by Posttranslational Modification[W

    PubMed Central

    Krügel, Undine; Veenhoff, Liesbeth M.; Langbein, Jennifer; Wiederhold, Elena; Liesche, Johannes; Friedrich, Thomas; Grimm, Bernhard; Martinoia, Enrico; Poolman, Bert; Kühn, Christina

    2008-01-01

    The plant sucrose transporter SUT1 from Solanum tuberosum revealed a dramatic redox-dependent increase in sucrose transport activity when heterologously expressed in Saccharomyces cerevisiae. Plant plasma membrane vesicles do not show any change in proton flux across the plasma membrane in the presence of redox reagents, indicating a SUT1-specific effect of redox reagents. Redox-dependent sucrose transport activity was confirmed electrophysiologically in Xenopus laevis oocytes with SUT1 from maize (Zea mays). Localization studies of green fluorescent protein fusion constructs showed that an oxidative environment increased the targeting of SUT1 to the plasma membrane where the protein concentrates in 200- to 300-nm raft-like microdomains. Using plant plasma membranes, St SUT1 can be detected in the detergent-resistant membrane fraction. Importantly, in yeast and in plants, oxidative reagents induced a shift in the monomer to dimer equilibrium of the St SUT1 protein and increased the fraction of dimer. Biochemical methods confirmed the capacity of SUT1 to form a dimer in plants and yeast cells in a redox-dependent manner. Blue native PAGE, chemical cross-linking, and immunoprecipitation, as well as the analysis of transgenic plants with reduced expression of St SUT1, confirmed the dimerization of St SUT1 and Sl SUT1 (from Solanum lycopersicum) in planta. The ability to form homodimers in plant cells was analyzed by the split yellow fluorescent protein technique in transiently transformed tobacco (Nicotiana tabacum) leaves and protoplasts. Oligomerization seems to be cell type specific since under native-like conditions, a phloem-specific reduction of the dimeric form of the St SUT1 protein was detectable in SUT1 antisense plants, whereas constitutively inhibited antisense plants showed reduction only of the monomeric form. The role of redox control of sucrose transport in plants is discussed. PMID:18790827

  8. Unclassified Source Term and Radionuclide Data for the Groundwater Flow and Contaminant Transport Model of Corrective Action Units 101 and 102: Central and Western Pahute Mesa, Nye County, Nevada, Revision 0

    SciTech Connect

    McCord, John

    2004-08-01

    This report documents the evaluation of the information and data available on the unclassified source term and radionuclide contamination for Central and Western Pahute Mesa: Corrective Action Units (CAUs) 101 and 102.

  9. Analysis of Transportation and Logistics Challenges Affecting the Deployment of Larger Wind Turbines: Summary of Results

    SciTech Connect

    Cotrell, J.; Stehly, T.; Johnson, J.; Roberts, J. O.; Parker, Z.; Scott, G.; Heimiller, D.

    2014-01-01

    There is relatively little literature that characterizes transportation and logistics challenges and the associated effects on U.S. wind markets. The objectives of this study were to identify the transportation and logistics challenges, assess the associated impacts, and provide recommendations for strategies and specific actions to address the challenges. The authors primarily relied on interviews with wind industry project developers, original equipment manufacturers, and transportation and logistics companies to obtain the information and industry perspectives needed for this study. They also reviewed published literature on trends and developments in increasing wind turbine size, logistics, and transportation issues.

  10. Peclet number as affected by molecular diffusion controls transient anomalous transport in alluvial aquifer-aquitard complexes

    USGS Publications Warehouse

    Zhang, Yong; Green, Christopher T.; Tick, Geoffrey R.

    2015-01-01

    This study evaluates the role of the Peclet number as affected by molecular diffusion in transient anomalous transport, which is one of the major knowledge gaps in anomalous transport, by combining Monte Carlo simulations and stochastic model analysis. Two alluvial settings containing either short- or long-connected hydrofacies are generated and used as media for flow and transport modeling. Numerical experiments show that 1) the Peclet number affects both the duration of the power-law segment of tracer breakthrough curves (BTCs) and the transition rate from anomalous to Fickian transport by determining the solute residence time for a given low-permeability layer, 2) mechanical dispersion has a limited contribution to the anomalous characteristics of late-time transport as compared to molecular diffusion due to an almost negligible velocity in floodplain deposits, and 3) the initial source dimensions only enhance the power-law tail of the BTCs at short travel distances. A tempered stable stochastic (TSS) model is then applied to analyze the modeled transport. Applications show that the time-nonlocal parameters in the TSS model relate to the Peclet number, Pe. In particular, the truncation parameter in the TSS model increases nonlinearly with a decrease in Pe due to the decrease of the mean residence time, and the capacity coefficient increases with an increase in molecular diffusion which is probably due to the increase in the number of immobile particles. The above numerical experiments and stochastic analysis therefore reveal that the Peclet number as affected by molecular diffusion controls transient anomalous transport in alluvial aquifer–aquitard complexes.

  11. Peclet number as affected by molecular diffusion controls transient anomalous transport in alluvial aquifer-aquitard complexes.

    PubMed

    Zhang, Yong; Green, Christopher T; Tick, Geoffrey R

    2015-01-01

    This study evaluates the role of the Peclet number as affected by molecular diffusion in transient anomalous transport, which is one of the major knowledge gaps in anomalous transport, by combining Monte Carlo simulations and stochastic model analysis. Two alluvial settings containing either short- or long-connected hydrofacies are generated and used as media for flow and transport modeling. Numerical experiments show that 1) the Peclet number affects both the duration of the power-law segment of tracer breakthrough curves (BTCs) and the transition rate from anomalous to Fickian transport by determining the solute residence time for a given low-permeability layer, 2) mechanical dispersion has a limited contribution to the anomalous characteristics of late-time transport as compared to molecular diffusion due to an almost negligible velocity in floodplain deposits, and 3) the initial source dimensions only enhance the power-law tail of the BTCs at short travel distances. A tempered stable stochastic (TSS) model is then applied to analyze the modeled transport. Applications show that the time-nonlocal parameters in the TSS model relate to the Peclet number, Pe. In particular, the truncation parameter in the TSS model increases nonlinearly with a decrease in Pe due to the decrease of the mean residence time, and the capacity coefficient increases with an increase in molecular diffusion which is probably due to the increase in the number of immobile particles. The above numerical experiments and stochastic analysis therefore reveal that the Peclet number as affected by molecular diffusion controls transient anomalous transport in alluvial aquifer-aquitard complexes.

  12. Radionuclide distributions and migration mechanisms at shallow land burial sites

    SciTech Connect

    Kirby, L.J.; Toste, A.P.; Thomas, C.W.; Rickard, W.H.; Nielson, H.L.; Campbell, R.M.; McShane, M.C.; Wilkerson, C.L.; Robertson, D.E.

    1991-02-01

    During the past several years, Pacific Northwest Laboratory (PNL) has conducted research at the Maxey Flats Disposal Site (MFDS) for the US Nuclear Regulatory Commission (NRC). This work has identified the spectrum of radionuclides present in the waste trenches, determined the processes that were occurring relative to degradation of radioactive material within the burial trenches, determined the chemical and physical characteristics of the trench leachates and the chemical forms of the leached radionuclides, determined the mobility of these radionuclides, investigated the subsurface and surface transport processes, determined the biological uptake by the native vegetation, developed strategies for environmental monitoring, and investigated other factors that influence the long-term fate of the radionuclide inventory at the disposal site. This report is a final summary of the research conducted by PNL and presents the results and discussions relative to the above investigative areas. 45 refs., 31 figs., 17 tabs.

  13. Potassium nutrition and water availability affect phloem transport of photosynthetic carbon in eucalypt trees

    NASA Astrophysics Data System (ADS)

    Epron, Daniel; Cabral, Osvaldo; Laclau, Jean-Paul; Dannoura, Masako; Packer, Ana Paula; Plain, Caroline; Battie-Laclau, Patricia; Moreira, Marcelo; Trivelin, Paulo; Bouillet, Jean-Pierre; Gérant, Dominique; Nouvellon, Yann

    2015-04-01

    Potassium fertilisation strongly affects growth and carbon partitioning of eucalypt on tropical soil that are strongly weathered. In addition, potassium fertilization could be of great interest in mitigating the adverse consequences of drought in planted forests, as foliar K concentrations influence osmotic adjustment, stomatal regulation and phloem loading. Phloem is the main pathway for transferring photosynthate from source leaves to sink organs, thus controlling growth partitioning among the different tree compartments. But little is known about the effect of potassium nutrition on phloem transport of photosynthetic carbon and on the interaction between K nutrition and water availability. In situ 13C pulse labelling was conducted on tropical eucalypt trees (Eucalyptus grandis L.) grown in a trial plantation with plots in which 37% of throughfall were excluded (about 500 mm/yr) using home-made transparent gutters (-W) or not (+W) and plots that received 0.45 mol K m-2 applied as KCl three months after planting (+K) or not (-K). Three trees were labelled in each of the four treatments (+K+W, +K-W, -K+W and -K-W). Trees were labelled for one hour by injecting pure 13CO2 in a 27 m3 whole crown chamber. We estimated the velocity of carbon transfer in the trunk by comparing time lags between the uptake of 13CO2 and its recovery in trunk CO2 efflux recorded by off axis integrated cavity output spectroscopy (Los Gatos Research) in two chambers per tree, one just under the crown and one at the base of the trunk. We analyzed the dynamics of the label recovered in the foliage and in the phloem sap by analysing carbon isotope composition of bulk leaf organic matter and phloem extracts using an isotope ratio mass spectrometer. The velocity of carbon transfer in the trunk and the initial rate 13C disappearance from the foliage were much higher in +K trees than in -K trees with no significant effect of rainfall. The volumetric flow of phloem, roughly estimated by multiplying

  14. Analysis of Transportation and Logistics Challenges Affecting the Deployment of Larger Wind Turbines: Summary of Results

    SciTech Connect

    J. Cotrell, T. Stehly, J. Johnson, J. O. Roberts, Z. Parker, G. Scott, and D. Heimiller

    2014-01-28

    The objectives of this study were to identify the transportation and logistics challenges, assess the associated impacts, and provide recommendations for strategies and specific actions to address the challenges.

  15. Putative Membrane-Bound Transporters MFSD14A and MFSD14B Are Neuronal and Affected by Nutrient Availability

    PubMed Central

    Lekholm, Emilia; Perland, Emelie; Eriksson, Mikaela M.; Hellsten, Sofie V.; Lindberg, Frida A.; Rostami, Jinar; Fredriksson, Robert

    2017-01-01

    Characterization of orphan transporters is of importance due to their involvement in cellular homeostasis but also in pharmacokinetics and pharmacodynamics. The tissue and cellular localization, as well as function, is still unknown for many of the solute carriers belonging to the major facilitator superfamily (MFS) Pfam clan. Here, we have characterized two putative novel transporters MFSD14A (HIAT1) and MFSD14B (HIATL1) in the mouse central nervous system and found protein staining throughout the adult mouse brain. Both transporters localized to neurons and MFSD14A co-localized with the Golgi marker Giantin in primary embryonic cortex cultures, while MFSD14B staining co-localized with an endoplasmic retention marker, KDEL. Based on phylogenetic clustering analyses, we predict both to have organic substrate profiles, and possible involvement in energy homeostasis. Therefore, we monitored gene regulation changes in mouse embryonic primary cultures after amino acid starvations and found both transporters to be upregulated after 3 h of starvation. Interestingly, in mice subjected to 24 h of food starvation, both transporters were downregulated in the hypothalamus, while Mfsd14a was also downregulated in the brainstem. In addition, in mice fed a high fat diet (HFD), upregulation of both transporters was seen in the striatum. Both MFSD14A and MFSD14B were intracellular neuronal membrane-bound proteins, expressed in the Golgi and Endoplasmic reticulum, affected by both starvation and HFD to varying degree in the mouse brain. PMID:28179877

  16. Targeted radionuclide therapy

    PubMed Central

    Williams, Lawrence E.; DeNardo, Gerald L.; Meredith, Ruby F.

    2008-01-01

    Targeted radionuclide therapy (TRT) seeks molecular and functional targets within patient tumor sites. A number of agents have been constructed and labeled with beta, alpha, and Auger emitters. Radionuclide carriers spanning a broad range of sizes; e.g., antibodies, liposomes, and constructs such as nanoparticles have been used in these studies. Uptake, in percent-injected dose per gram of malignant tissue, is used to evaluate the specificity of the targeting vehicle. Lymphoma (B-cell) has been the primary clinical application. Extension to solid tumors will require raising the macroscopic absorbed dose by several-fold over values found in present technology. Methods that may effect such changes include multistep targeting, simultaneous chemotherapy, and external sequestration of the agent. Toxicity has primarily involved red marrow so that marrow replacement can also be used to enhance future TRT treatments. Correlation of toxicities and treatment efficiency has been limited by relatively poor absorbed dose estimates partly because of using standard (phantom) organ sizes. These associations will be improved in the future by obtaining patient-specific organ size and activity data with hybrid SPECT∕CT and PET∕CT scanners. PMID:18697529

  17. Biomolecular Mechanisms Controlling Metal and Radionuclide Transformations in Anaeromyxobacter dehalogenans

    SciTech Connect

    Beliaev, Alexander S.; Fredrickson, James K.; Loeffler, Frank E.; Sanford, Robert A.

    2006-06-01

    Microbiological reduction and immobilization of U(VI) and Tc(VII) has been proposed as a strategy for remediating radionuclide-contaminated environments. Numerous studies focusing on the reduction kinetics and speciation of these metals have been carried out using contaminated sediment samples, microbial consortia, and pure bacterial cultures. While previous work with model organisms has increased the general understanding of radionuclide transformation processes, fundamental questions regarding radionuclide reduction mechanisms by indigenous microorganisms are poorly understood, especially under the commonly encountered scenario where multiple electron acceptors are present. Therefore, the overall goal of the proposed research is to elucidate the molecular mechanisms of radionuclide biotransformation by Anaeromyxobacter dehalogenans, a predominant member of indigenous microorganism commonly found in contaminated subsurface environments, and to assess the effects of relevant environmental factors affecting these transformation reactions.

  18. Numerical modeling of radionuclide migration through a borehole disposal site.

    PubMed

    Yeboah, Serwaa; Akiti, Thomas T; Fletcher, John J

    2014-01-01

    The migration of radionuclides from a borehole repository located about 20 km from the Akwapim fault line which lies in an area of high seismicity was analyzed for some selected radionuclides. In the event of a seismic activity, fractures and faults could be rejuvenated or initiated resulting in container failure leading to the release of radionuclides. A numerical model was solved using a two-dimensional finite element code (Comsol Multiphysics) by taking into account the effect of heterogeneities. Results showed that, the fractured medium created preferential pathways indicating that, fault zones generated potential paths for released radionuclides from a radioactive waste repository. The results obtained showed that variations in hydraulic conductivity as a result of the heterogeneity considered within the domain significantly affected the direction of flow.

  19. Reactor-Produced Medical Radionuclides

    SciTech Connect

    Mirzadeh, Saed; Mausner, Leonard; Garland, Marc A

    2011-01-01

    The therapeutic use of radionuclides in nuclear medicine, oncology and cardiology is the most rapidly growing use of medical radionuclides. Since most therapeutic radionuclides are neutron rich and decay by beta emission, they are reactor-produced. This chapter deals mainly with production approaches with neutrons. Neutron interactions with matter, neutron transmission and activation rates, and neutron spectra of nuclear reactors are discussed in some detail. Further, a short discussion of the neutron-energy dependence of cross sections, reaction rates in thermal reactors, cross section measurements and flux monitoring, and general equations governing the reactor production of radionuclides are presented. Finally, the chapter is concluded by providing a number of examples encompassing the various possible reaction routes for production of a number of medical radionuclides in a reactor.

  20. Analysis of matrix effects critical to microbial transport in organic waste-affected soils across laboratory and field scales

    NASA Astrophysics Data System (ADS)

    Unc, Adrian; Goss, Michael J.; Cook, Simon; Li, Xunde; Atwill, Edward R.; Harter, Thomas

    2012-06-01

    Organic waste applications to soil (manure, various wastewaters, and biosolids) are among the most significant sources of bacterial contamination in surface and groundwater. Transport of bacteria through the vadose zone depends on flow path geometry and stability and is mitigated by interaction between soil, soil solution, air-water interfaces, and characteristics of microbial surfaces. After initial entry, the transport through soil depends on continued entrainment of bacteria and resuspension of those retained in the porous structure. We evaluated the retention of bacteria-sized artificial microspheres, varying in diameter and surface charge and applied in different suspending solutions, by a range of sieved soils contained in minicolumns, the transport of hydrophobic bacteria-sized microspheres through undisturbed soil columns as affected by waste type under simulated rainfall, and the field-scale transport of Enterococcus spp. to an unconfined sandy aquifer after the application of liquid manure. Microsphere retention reflected microsphere properties. The soil type and suspending solution affected retention of hydrophilic but not hydrophobic particles. Retention was not necessarily facilitated by manure-microsphere-soil interactions but by manure-soil interactions. Undisturbed column studies confirmed the governing role of waste type on vadose-zone microsphere transport. Filtration theory applied as an integrated analysis of transport across length scales showed that effective collision efficiency depended on the distance of travel. It followed a power law behavior with the power coefficient varying from ˜0.4 over short distances to >0.9 over 1 m (i.e., very little filtration for a finite fraction of biocolloids), consistent with reduced influence of soil solution and biocolloid properties at longer travel distances.

  1. Fosfomycin resistance plasmids do not affect fosfomycin transport into Escherichia coli.

    PubMed Central

    León, J; García-Lobo, J M; Ortiz, J M

    1982-01-01

    Escherichia coli cells carrying fosfomycin resistance plasmids were able to take up fosfomycin from the medium to the same extent as plasmid-free bacteria. The antibiotic entered the plasmid-harboring cells by means of the glpT and uhp transport systems, as is the case with susceptible bacteria. Active fosfomycin could be detected in soluble extracts of cells which had previously been incubated in the presence of the antibiotic. Furthermore, fosfomycin resistance plasmids did not confer on E. coli cells resistance to the novel antibiotic FR-31564, which is incorporated by the same transport systems as fosfomycin. We conclude that, in contrast to chromosomal resistance mutants, altered transport does not play a role in the plasmid-encoded fosfomycin resistance mechanism. PMID:7044304

  2. Dietary inulin affects the morphology but not the sodium-dependent glucose and glutamine transport in the jejunum of broilers.

    PubMed

    Rehman, H; Rosenkranz, C; Böhm, J; Zentek, J

    2007-01-01

    Inulin, a prebiotic, is a fermentable oligosaccharide that may affect the intestinal mucosal architecture and the electrophysiological parameters. The effects of a diet with added inulin were tested on the jejunal morphology and electrogenic transport of Glc and Gln from the jejunal mucosa in broilers. Short-circuit current and transmucosal tissue resistance of jejunal flaps were measured in Ussing chambers. The feeding experiment was carried out in broilers (n = 40) using 1% inulin with an application period of 5 wk. The inulin-containing diet resulted in longer jejunal villi (P < 0.05) and deeper crypts (P < 0.01) than in control birds without affecting villus:crypt depth. Basal short-circuit current value remained unaffected by dietary treatment. Inulin supplementation did not modify the electrogenic transport of Glc and Gln in the jejunal mucosa. The basal value of transmucosal tissue resistance was significantly lower (P < 0.001) in the inulin-fed group compared with the control group. In conclusion, inulin supplementation affected the jejunal mucosal architecture but did not modify the electrogenic transport of Glc and amino acid under present experimental condition.

  3. Radionuclide complexation in xylem exudates of plants

    SciTech Connect

    Cataldo, D.A.; McFadden, D.M.; Garland, T.R.; Wildung, R.E.

    1985-04-01

    The plant xylem is the primary avenue for transport of nutrient and pollutant elements from the roots of aerial portions of the plant. It is proposed that the transport of reactive or hydrolyzable ions is facilitated by the formation of stable/soluble complexes with organic metabolites. The xylem exudates of soybean (Glycine max cv. Williams) were characterized as to their inorganic and organic components, complexation patterns for radionuclides, both in vivo and in vitro, and for class fractions of exudates using thin-layer electrophoresis. The radionuclides Pu-238 and Fe-59 were found primarily as organic acid complexes, while Ni-63 and Cd-109 were associated primarily with components of the amono acid fraction. Technetium-99 was found to be uncomplexed and transported as the pertechnetate ion. It was not possible to duplicate fully complexes formed in vivo by back reaction with whole exudates or class fractions, indicating the possible importance of plant induction processes, reaction kinetics and/or the formation of mixed ligand complexes. 28 refs., 4 figs.

  4. [Aero-transport of a MDR-TB affected patient with bio-containment systems].

    PubMed

    Lastilla, M; Bisetti, R; Autore, A; Aragonese, F; Di Stefano, M; Sarlo, O

    2007-01-01

    The Italian Air Force medical service, in order to attend to its duty, has to deal with the search, rescue and aero-medical evacuation of the wounded and sick. Due to the increase of air transportation, the likelihood of contracting disease, such as haemorrhagic fevers has risen and it is necessary to know how to treat a patient abroad suffering from severe infectious disease without running any risk either for the medical personnel or for the air crew. The military sanitary service of the Air Force has been preparing for this purpose through a meticulous preparation in Italy and in the USA in order to satisfy these need and through the use of stretchers specifically designed to transport highly contagious patients: Aircraft Transit Isolators (ATIs) and Stretcher Transit Isolators (STIs). These particular medical tools are provided by filter HEPA and they are completely insulated in a PVC envelope. The former (ATI) is used to transport the patient by airplane, the latter is used for road travel. Last January 24th the first real mission was performed transporting a severe TBC-MDR (case) from Alghero to Milan. All went well and the patient left the hospital of Sondalo two months later.

  5. 77 FR 59840 - Statutory Amendments Affecting Transportation of Agricultural Commodities and Farm Supplies

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-01

    ... retail store deliveries. Thus, it is clear Congress intended to limit this exemption to retail... transportation from a retail distribution point of the farm supply to a location (farm or other location where the farm supply product would be used) within a 100 air-mile radius of the retail distribution...

  6. Yeast culture supplement during nursing and transport affects immunity and intestinal microbial ecology of weanling pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weaning and transport stress can have a negative impact on the piglet's immune system and intestinal microbiota. The objective of this study was to determine the influence of a yeast product on innate immunity and microbial ecology of the gastrointestinal tract following stress of weaning and trans...

  7. Runoff nutrient transport as affected by land application method, swine growth stage, and runoff rate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was conducted to measure the effects of slurry application method, swine growth stage, and flow rate on runoff nutrient transport. Swine slurry was obtained from production units containing grower pigs, finisher pigs, or sows and gilts. The swine slurry was applied using broadcast, disk, ...

  8. Intestinal microbial affects of yeast products on weaned and transport stressed pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Study objectives were to determine effects of a commercially available yeast product (XPC, Diamond-V Mills) and stress of transportation on total Enterobacteriaceae, Escherichia coli, coliforms, and Lactobacilli populations in the intestine of weaning pigs. In a RCB design with a 2 x 2 factorial ar...

  9. A mutation in protein phosphatase 2A regulatory subunit A affects auxin transport in Arabidopsis

    NASA Technical Reports Server (NTRS)

    Garbers, C.; DeLong, A.; Deruere, J.; Bernasconi, P.; Soll, D.; Evans, M. L. (Principal Investigator)

    1996-01-01

    The phytohormone auxin controls processes such as cell elongation, root hair development and root branching. Tropisms, growth curvatures triggered by gravity, light and touch, are also auxin-mediated responses. Auxin is synthesized in the shoot apex and transported through the stem, but the molecular mechanism of auxin transport is not well understood. Naphthylphthalamic acid (NPA) and other inhibitors of auxin transport block tropic curvature responses and inhibit root and shoot elongation. We have isolated a novel Arabidopsis thaliana mutant designated roots curl in NPA (rcn1). Mutant seedlings exhibit altered responses to NPA in root curling and hypocotyl elongation. Auxin efflux in mutant seedlings displays increased sensitivity to NPA. The rcn1 mutation was transferred-DNA (T-DNA) tagged and sequences flanking the T-DNA insert were cloned. Analysis of the RCN1 cDNA reveals that the T-DNA insertion disrupts a gene for the regulatory A subunit of protein phosphatase 2A (PP2A-A). The RCN1 gene rescues the rcn1 mutant phenotype and also complements the temperature-sensitive phenotype of the Saccharomyces cerevisiae PP2A-A mutation, tpd3-1. These data implicate protein phosphatase 2A in the regulation of auxin transport in Arabidopsis.

  10. A mutation in protein phosphatase 2A regulatory subunit A affects auxin transport in Arabidopsis.

    PubMed Central

    Garbers, C; DeLong, A; Deruére, J; Bernasconi, P; Söll, D

    1996-01-01

    The phytohormone auxin controls processes such as cell elongation, root hair development and root branching. Tropisms, growth curvatures triggered by gravity, light and touch, are also auxin-mediated responses. Auxin is synthesized in the shoot apex and transported through the stem, but the molecular mechanism of auxin transport is not well understood. Naphthylphthalamic acid (NPA) and other inhibitors of auxin transport block tropic curvature responses and inhibit root and shoot elongation. We have isolated a novel Arabidopsis thaliana mutant designated roots curl in NPA (rcn1). Mutant seedlings exhibit altered responses to NPA in root curling and hypocotyl elongation. Auxin efflux in mutant seedlings displays increased sensitivity to NPA. The rcn1 mutation was transferred-DNA (T-DNA) tagged and sequences flanking the T-DNA insert were cloned. Analysis of the RCN1 cDNA reveals that the T-DNA insertion disrupts a gene for the regulatory A subunit of protein phosphatase 2A (PP2A-A). The RCN1 gene rescues the rcn1 mutant phenotype and also complements the temperature-sensitive phenotype of the Saccharomyces cerevisiae PP2A-A mutation, tpd3-1. These data implicate protein phosphatase 2A in the regulation of auxin transport in Arabidopsis. Images PMID:8641277

  11. Oxic and anoxic conditions affect arsenic (As) accumulation and arsenite transporter expression in rice.

    PubMed

    Wu, Chuan; Huang, Liu; Xue, Sheng-Guo; Pan, Wei-Song; Zou, Qi; Hartley, William; Wong, Ming-Hung

    2017-02-01

    Arsenic (As) exposure from rice consumption has now become a global health issue. This study aimed to investigate the effects of rice rhizosphere oxic conditions on silicate transporter (responsible for arsenite transportation) expressions, and on As accumulation and speciation in four rice genotypes, including two hybrid genotypes (Xiangfengyou9, Shenyou9586) and two indica subspecies (Xiangwanxian17, Xiangwanxian12). Oxic and anoxic treatments have different effects on root length (p < 0.001) and weight (p < 0.05). Total As concentrations in roots were dramatically lower in oxic treatments (88.8-218 mg/kg), compared to anoxic treatments (147-243 mg/kg) (p < 0.001). Moreover, root and shoot arsenite concentrations in oxic treatments were lower than that in anoxic treatments in arsenite treatments. The relative abundance of silicate transporter expressions displayed a trend of down-regulation in oxic treatments compared to anoxic treatments, especially significantly different for Xiangwanxian17, Xiangwanxian12 in Lsi1 expressions (p < 0.05), Xiangfengyou9, Shenyou9586, Xiangwanxian17 in Lsi2 expressions (p < 0.05). However, there were no significant differences of transporter expressions in different As treatments and genotypes. It may be a possible reason for low As accumulation in rice growing aerobically compared to flooded condition and a potential route to reduce the health risk of As in rice.

  12. Transport of manure-borne testosterone in soils affected by artificial rainfall events.

    PubMed

    Qi, Yong; Zhang, Tian C

    2016-04-15

    Information is very limited on fate and transport of steroidal hormones in soils. In this study, the rainfall simulation tests were conducted with a soil slab reactor to investigate the transport of manure-borne testosterone in a silty-clay loam soil under six controllable operation conditions (i.e., three rainfall intensities and two tillage practices). The properties [e.g., rainwater volume, particle size distribution (PSD)] of the slurry samples collected in runoff and leachate at different time intervals were measured; their correlation with the distribution of testosterone among runoff, leachate and soil matrix was analyzed. The results indicated that more than 88% of the testosterone was held by the applied manure and/or soil matrix even under the rainfall intensity of 100-year return frequency. The runoff facilitated testosterone transport through both dissolved and particle-associated phases, with the corresponding mass ratio being ∼7 to 3. Soil particles collected through runoff were mainly silt-sized aggregates (STA) and clays, indicating the necessity of using partially-dispersed soil particles as testing materials to conduct batch tests (e.g., sorption/desorption). No testosterone was detected at the soil depth >20 cm or in the leachate samples, indicating that transport of testosterone through the soil is very slow when there is no preferential flow. Tillage practice could impede the transport of testosterone in runoff. For the first time, results and the methodologies of this study allow one to quantify the hormone distribution among runoff, leachate and soil matrix at the same time and to obtain a comprehensive picture of the F/T of manure-borne testosterone in soil-water environments.

  13. Studying the anthropogenic radionuclides in Puerto Rico: Preliminary Result

    NASA Astrophysics Data System (ADS)

    Ithier-Guzmán, W.; Pyrtle, A. J.; Smoak, J.

    2004-12-01

    Local introduction of anthropogenic radionuclides to Puerto Rico's terrestrial and aquatic environments began in 1962 as a result of US government-sponsored research activities. Some of the earlier experiments examined the effects of radiation in tropical rainforests and the potential of superheated boiling nuclear reactor technology. More recent activities involved the use of depleted uranium during military exercises on Vieques. While the presence of radionuclides in Puerto Rico is documented, little research has been done to assess the environmental impact of this anthropogenic material. After entering Puerto Rico's environment, it is likely that some radionuclides are transported away from initial introduction sites. It is important that the distributions and behavior of radionuclides in Puerto Rico be determined. As such an investigation of this material throughout Puerto Rico was initiated. Sediment Cs-137 and Pb-210 activities, as well as ancillary geochemistry data are presented. These preliminary findings will be utilized as part of an ongoing study to determine radionuclide distributions and behaviors, with respect to aquatic geochemistry and dominant transport processes.

  14. Allocation, stress tolerance and carbon transport in plants: how does phloem physiology affect plant ecology?

    PubMed

    Savage, Jessica A; Clearwater, Michael J; Haines, Dustin F; Klein, Tamir; Mencuccini, Maurizio; Sevanto, Sanna; Turgeon, Robert; Zhang, Cankui

    2016-04-01

    Despite the crucial role of carbon transport in whole plant physiology and its impact on plant-environment interactions and ecosystem function, relatively little research has tried to examine how phloem physiology impacts plant ecology. In this review, we highlight several areas of active research where inquiry into phloem physiology has increased our understanding of whole plant function and ecological processes. We consider how xylem-phloem interactions impact plant drought tolerance and reproduction, how phloem transport influences carbon allocation in trees and carbon cycling in ecosystems and how phloem function mediates plant relations with insects, pests, microbes and symbiotes. We argue that in spite of challenges that exist in studying phloem physiology, it is critical that we consider the role of this dynamic vascular system when examining the relationship between plants and their biotic and abiotic environment.

  15. Wave-induced mass transport affects daily Escherichia coli fluctuations in nearshore water

    USGS Publications Warehouse

    Ge, Zhongfu; Whitman, Richard L.; Nevers, Meredith B.; Phanikumar, Mantha S.

    2012-01-01

    Characterization of diel variability of fecal indicator bacteria concentration in nearshore waters is of particular importance for development of water sampling standards and protection of public health. Significant nighttime increase in Escherichia coli (E. coli) concentration in beach water, previously observed at marine sites, has also been identified in summer 2000 from fixed locations in waist- and knee-deep waters at Chicago 63rd Street Beach, an embayed, tideless, freshwater beach with low currents at night (approximately 0.015 m s–1). A theoretical model using wave-induced mass transport velocity for advection was developed to assess the contribution of surface waves to the observed nighttime E. coli replenishment in the nearshore water. Using average wave conditions for the summer season of year 2000, the model predicted an amount of E. coli transported from water of intermediate depth, where sediment resuspension occurred intermittently, that would be sufficient to have elevated E. coli concentration in the surf and swash zones as observed. The nighttime replenishment of E. coli in the surf and swash zones revealed here is an important phase in the cycle of diel variations of E. coli concentration in nearshore water. According to previous findings in Ge et al. (Environ. Sci. Technol. 2010, 44, 6731–6737), enhanced current circulation in the embayment during the day tends to displace and deposit material offshore, which partially sets up the system by the early evening for a new period of nighttime onshore movement. This wave-induced mass transport effect, although facilitating a significant base supply of material shoreward, can be perturbed or significantly influenced by high currents (orders of magnitude larger than a typical wave-induced mass transport velocity), current-induced turbulence, and tidal forcing.

  16. Temperature affects transport of polysaccharides and proteins in articular cartilage explants.

    PubMed

    Moeini, Mohammad; Lee, Kwan-Bong; Quinn, Thomas M

    2012-07-26

    Solute transport phenomena mediate many aspects of the physiology and contrast agent-based clinical imaging of articular cartilage. Temperatures up to 10°C below standard body temperature (37°C) are common in articulating joints during normal activities and clinically (e.g. cold treatment of injuries). Therefore it is of interest to characterize the effects of temperature changes on solute transport parameters in cartilage. A range of fluorescent solutes including fluorescein isothiocyanate, 4 and 40kDa dextrans, myoglobin, insulin and chondroitin sulfate were prepared and used in assays of solute effective partition coefficient and effective diffusivity in bovine intermediate zone articular cartilage explants maintained at 10, 22 or 37°C. Trends for increasing partition coefficient with increasing temperature were evident for all solutes except chondroitin sulfate, with significant changes between 22 and 37°C for 4kDa dextran, insulin and myoglobin. Diffusivities of most solutes tested also tended to increase with increasing temperature, with significant changes between 10 and 22°C for FITC, 40kDa dextran and myoglobin. Oddly, insulin diffusivity decreased significantly as temperature increased from 22 to 37°C while chondroitin sulfate diffusivity exhibited no clear temperature dependence. These results highlight solute-specific temperature dependences of transport phenomena which may depend upon molecular weight, chemical structure, molecular conformation, and solute-matrix and solute-solute interactions. The articular cartilage explants themselves exhibited small but significant changes in water and glycosaminoglycan contents during experiments, underscoring the importance of solute-matrix interactions. Solute transport parameters in cartilage and their temperature dependences are therefore not easily predicted, and case-by-case experimental determination may be essential.

  17. Wave-induced mass transport affects daily Escherichia coli fluctuations in nearshore water.

    PubMed

    Ge, Zhongfu; Whitman, Richard L; Nevers, Meredith B; Phanikumar, Mantha S

    2012-02-21

    Characterization of diel variability of fecal indicator bacteria concentration in nearshore waters is of particular importance for development of water sampling standards and protection of public health. Significant nighttime increase in Escherichia coli (E. coli) concentration in beach water, previously observed at marine sites, has also been identified in summer 2000 from fixed locations in waist- and knee-deep waters at Chicago 63rd Street Beach, an embayed, tideless, freshwater beach with low currents at night (approximately 0.015 m s(-1)). A theoretical model using wave-induced mass transport velocity for advection was developed to assess the contribution of surface waves to the observed nighttime E. coli replenishment in the nearshore water. Using average wave conditions for the summer season of year 2000, the model predicted an amount of E. coli transported from water of intermediate depth, where sediment resuspension occurred intermittently, that would be sufficient to have elevated E. coli concentration in the surf and swash zones as observed. The nighttime replenishment of E. coli in the surf and swash zones revealed here is an important phase in the cycle of diel variations of E. coli concentration in nearshore water. According to previous findings in Ge et al. (Environ. Sci. Technol. 2010, 44, 6731-6737), enhanced current circulation in the embayment during the day tends to displace and deposit material offshore, which partially sets up the system by the early evening for a new period of nighttime onshore movement. This wave-induced mass transport effect, although facilitating a significant base supply of material shoreward, can be perturbed or significantly influenced by high currents (orders of magnitude larger than a typical wave-induced mass transport velocity), current-induced turbulence, and tidal forcing.

  18. Mechanisms affecting the transport and retention of bacteria, bacteriophage and microspheres in laboratory-scale saturated fractures

    NASA Astrophysics Data System (ADS)

    Seggewiss, G.; Dickson, S. E.

    2013-12-01

    Groundwater is becoming an increasingly important water source due to the ever-increasing demands from agricultural, residential and industrial consumers. In search of more secure sources, wells are routinely finished over large vertical depths in bedrock aquifers, creating new hydraulic pathways and thus increasing the risk of cross contamination. Moreover, hydraulic pathways are also being altered and created by increasing water withdrawal rates from these wells. Currently, it is not well understood how biological contaminants are transported through, and retained in, fractured media thereby making risk assessment and land use decisions difficult. Colloid transport within fractured rock is a complex process with several mechanisms affecting transport and retention, including: advection, hydrodynamic dispersion, diffusion, size exclusion, adsorption, and decay. Several researchers have investigated the transport of bacteria, bacteriophage, and microspheres (both carboxylated and plain) to evaluate the effects of surface properties and size on transport and retention. These studies have suggested that transport is highly dependent on the physico-chemical properties of the particle, the fracture, and the carrying fluid. However, these studies contain little detail regarding the specific mechanisms responsible for transport beyond speculating about their existence. Further, little work has been done to compare the transport of these particulate materials through the same fracture, allowing for direct observations based on particulate size and surface properties. This research examines the similarities and differences in transport and retention between four different particles through two different laboratory-scale, saturated fractures. This work is designed to explore the effects of particle size, surface properties, ionic strength of the carrying solution, and aperture field characteristics on transport and retention in single, saturated fractures. The particulates

  19. Radionuclide therapy for arthritic knees

    SciTech Connect

    Doepel, L.K.

    1985-02-08

    A new radionuclide therapeutic approach for rheumatoid arthritis of the knee is described. This therapy combines a short-lived radionuclide with a carrier whose physical and chemical characteristics aid retention of the radioactive particles within the joint. Joining a radionuclide to a particulate carrier had not been explored previously as a potential method for inhibiting radiation leakage. The treatment couples the rare earth element dysprosium 165 to ferric hydroxide in macroaggregate form (size range: 3 to 10 ..mu..m). After the relatively inert iron complex penetrates the synovium, it causes cell death. Macrophages and phagocytes clear away the cellular debris, essentially eliminating the synovium.

  20. Proteins affecting thylakoid morphology - the key to understanding vesicle transport in chloroplasts?

    PubMed

    Lindquist, Emelie; Aronsson, Henrik

    2014-01-01

    We recently showed that a Rab protein, CPRabA5e (CP = chloroplast localized), is located in chloroplasts of Arabidopsis thaliana where it is involved in various processes, such as thylakoid biogenesis and vesicle transport. Using a yeast two-hybrid method, CPRabA5e was shown to interact with a number of chloroplast proteins, including the CURVATURE THYLAKOID 1A (CURT1A) protein and the light-harvesting chlorophyll a/b binding protein (LHCB1.5). CURT1A has recently been shown to modify thylakoid architecture by inducing membrane curvature in grana, whereas LHCB1.5 is a protein of PSII (Photosystem II) facilitating light capture. LHCB1.5 is imported to chloroplasts and transported to thylakoid membranes using the post-translational Signal Recognition Particle (SRP) pathway. With this information as starting point, we here discuss their subsequent protein-protein interactions, given by the literature and Interactome 3D. CURT1A itself and several of the proteins interacting with CURT1A and LHCB1.5 have relations to vesicle transport and thylakoid morphology, which are also characteristics of cprabA5e mutants. This highlights the previous hypothesis of an alternative thylakoid targeting pathway for LHC proteins using vesicles, in addition to the SRP pathway.

  1. Long-term variations of radionuclides in the Bratislava air.

    PubMed

    Sýkora, Ivan; Holý, Karol; Ješkovský, Miroslav; Müllerová, Monika; Bulko, Martin; Povinec, Pavel P

    2017-01-01

    Variations of aerosol radionuclides (2001-2015) in the ground-level air in Bratislava (Slovakia) showed (7)Be maxima in spring/early summer and minima in winter, however, an inverse trend was observed for (210)Pb, (137)Cs and (40)K. A decreasing amplitude and splitting of summer maxima for (7)Be in the last years has been found. A temporal behavior of the (7)Be/(210)Pb activity ratio showed higher levels during warm seasons due to vertical convection of air masses from higher altitudes. The (137)Cs activity concentration in the surface air between 2003 and 2010 was decreasing with an effective half-life of 1.9 ± 0.3 years. The yearly average (137)Cs concentrations during 2009-2014 were almost constant, disturbed only by the Fukushima accident in 2011. The increased atmospheric (137)Cs and (40)K levels observed during the autumn-winter season may be due to surface soil resuspension, biomass burning and radionuclide transport by winds. Seasonal variations of (222)Rn activity concentrations were found with maxima at the end of autumn and in winter, and minima in spring. The variability of the average annual course of (222)Rn has been larger than that of (210)Pb. The (210)Pb/(222)Rn activity ratio was highest at the end of winter and in the spring, while from June to December remained nearly constant. More intensive atmospheric mixing in spring months caused a decrease in the (222)Rn activity concentration, while the aerosol component of the atmosphere has been affected mainly during the autumn and winter seasons. The mean residence time of aerosols in the atmosphere was calculated using the (210)Pb/(222)Rn method to be 4.5 ± 0.9 days.

  2. Distribution coefficients for radionuclides in aquatic environments. Volume 2. Dialysis experiments in marine environments

    SciTech Connect

    Sibley, T.H.; Nevissi, A.E.; Schell, W.R.

    1981-05-01

    The overall objective of this research program was to obtain new information that can be used to predict the fate of radionuclides that may enter the aquatic environment from nuclear power plants, waste storage facilities or fuel reprocessing plants. Important parameters for determining fate are the distribution of radionuclides between the soluble and particulate phases and the partitioning of radionuclides among various suspended particulates. This report presents the results of dialysis experiments that were used to study the distribution of radionuclides among suspended sediments, phytoplankton, organic detritus, and filtered sea water. Three experiments were conducted to investigate the adsorption kinetics and equilibrium distribution of (59)Fe, (60)Co, (65)Zn, (106)Ru, (137)Cs, (207)Bi, (238)Pu, and (241)Am in marine system. Diffusion across the dialysis membranes depends upon the physico-chemical form of the radionuclides, proceeding quite rapidly for ionic species of (137)Cs and (60)Co but much more slowly for radionuclides which occur primarily as colloids and solid precipitates such as (59)Fe, (207)Bi, and (241)Am. All the radionuclides adsorb to suspended particulates although the amount of adsorption depends upon the specific types and concentration of particulates in the system and the selected radionuclide. High affinity of some radionuclides - e.g., (106)Ru and (241)Am - for detritus and phytoplankton suggests that suspended organics may significantly affect the eventual fate of those radionuclides in marine ecosystems.

  3. Bioaccumulation of radionuclides in fertilized Canadian Shield lake basins.

    PubMed

    Bird, G A; Hesslein, R H; Mills, K H; Schwartz, W J; Turner, M A

    1998-07-11

    Radionuclide tracers of heavy metals (59Fe, 60Co, 65Zn, 75Se, 85Sr, 134Cs and 203Hg) representing potential contamination from nuclear power plants, industry and agriculture were added to separate basins of Lake 226, Experimental Lakes Area, northwestern Ontario. The two basins were part of a eutrophication experiment and differed in their trophic status; the north basin (L226N) was eutrophic whereas the south basin (L226S) was mesotrophic. Our objective was to determine the uptake of the radionuclides by biota and the effect of lake trophic status on their bioaccumulation. The trophic status of the lakes did not appear to have a marked effect on the accumulation of radionuclides by the biota. This may have been because of a mid-summer leakage of nutrients between the basins which enhanced primary production in L226S, because there is a time lag between primary production and the availability of the radionuclides to the fishes or because trophic status does not affect the uptake of at least some of these radionuclides. However, there was a tendency for faster uptake of the radionuclides in L226N by fish than L226S, but the differences were not significant. Concentrations in the biota generally decreased in the order: fathead minnow > pearl dace > tadpoles > slimy sculpin > leeches. Concentrations in biota generally decreased in the order. 65Zn > 203Hg > 75Se > 134Cs > 60Co > 85Sr = 59Fe. Cobalt-60 concentrations in tadpoles were greater than in the other biota. Radionuclide concentrations in the tissues of lake whitefish indicated that uptake was predominantly from food. Radionuclide concentrations were usually higher in the posterior gut, liver and kidney than in other tissues, whereas body burdens were generally high in the muscle for 75Se, 134Cs and 203Hg; kidney and gut for 60Co; and bone for 65Zn and 75Se. Mercury-203 burdens were also high in the bone and gut.

  4. Visualizing plumes of heavy metals and radionuclides

    NASA Astrophysics Data System (ADS)

    Prigiobbe, V.; Liu, T.; Bryant, S. L.; Hesse, M. A.

    2015-12-01

    The understanding of the transport behaviors in porous media resides on the ability to reproduce fundamental phenomena in a lab setting. Experiments with quasi 2D tanks filled with beads are performed to study physical phenomena induced by chemical and fluid dynamic processes. When an alkaline solution containing heavy metals or radionuclides invades a low pH region, mixing due to longitudinal dispersion induces destabilization of the front forming a fast travelling pulse [1]. When the two fluids travel in parallel, instead, mixing induced by transverse dispersion creates a continuous leakage from the alkaline region into the acidic one forming a fast travelling plume [2] (Figure 1). Impact of these phenomena are on aquifers upon leaking of alkaline fluids, rich in heavy metals and radionuclides, from waste storage sites. Here, we report the results from a study where experiments with a quasi 2D tank are performed to analyze the effect of transverse mixing on strontium (Sr2+) transport. To visualize the leaking plume, a fluorescent dye (Fura-2) is added the acidic solution, which has been widely used in biomedical applications [3]. It is the aim of this work to optimize its application under the conditions relevant to this work. Spectrometric measurements of absorption and fluorescence show sensitivity of the dye to the presence of Sr2+ throughout a broad range of pH and Sr2+ concentration (Figure 2). In the absence of Sr2+, no significant absorption and fluorescence was measured, but as Sr2+ was added the relevant peaks increase significantly and sample dilution of tenfold was required to remain within the measuring threshold. These results show a strong sensitivity of the dye to the cation opening the opportunity to use Fura-2 as a tool to visualize heavy metals and radionuclides plumes. References[1] Prigiobbe et al. (2012) GRL 39, L18401. [2] Prigiobbe and Hesse (2015) in preparation. [3] Xu-Friedman and Regehr (2000) J. Neurosci. 20(12) 4414-4422.

  5. Meteorological Processes Affecting the Transport of Emissions from the Navajo Generating Station to Grand Canyon National Park.

    NASA Astrophysics Data System (ADS)

    Lindsey, Charles G.; Chen, Jun; Dye, Timothy S.; Willard Richards, L.; Blumenthal, Donald L.

    1999-08-01

    During the 1990 Navajo Generating Station (NGS) Winter Visibility Study, a network of surface and upper-air meteorological measurement systems was operated in and around Grand Canyon National Park to investigate atmospheric processes in complex terrain that affected the transport of emissions from the nearby NGS. This network included 15 surface monitoring stations, eight balloon sounding stations (equipped with a mix of rawinsonde, tethersonde, and Airsonde sounding systems), three Doppler radar wind profilers, and four Doppler sodars. Measurements were made from 10 January through 31 March 1990. Data from this network were used to prepare objectively analyzed wind fields, trajectories, and streak lines to represent transport of emissions from the NGS, and to prepare isentropic analyses of the data. The results of these meteorological analyses were merged in the form of a computer animation that depicted the streak line analyses along with measurements of perfluorocarbon tracer, SO2, and sulfate aerosol concentrations, as well as visibility measurements collected by an extensive surface monitoring network. These analyses revealed that synoptic-scale circulations associated with the passage of low pressure systems followed by the formation of high pressure ridges accompanied the majority of cases when NGS emittants appeared to be transported to the Grand Canyon. The authors' results also revealed terrain influences on transport within the topography of the study area, especially mesoscale flows inside the Lake Powell basin and along the plain above the Marble Canyon.

  6. Transcription of hexose transporters of Saccharomyces cerevisiae is affected by change in oxygen provision

    PubMed Central

    Rintala, Eija; Wiebe, Marilyn G; Tamminen, Anu; Ruohonen, Laura; Penttilä, Merja

    2008-01-01

    Background The gene family of hexose transporters in Saccharomyces cerevisiae consists of 20 members; 18 genes encoding transporters (HXT1-HXT17, GAL2) and two genes encoding sensors (SNF3, RGT2). The effect of oxygen provision on the expression of these genes was studied in glucose-limited chemostat cultivations (D = 0.10 h-1, pH 5, 30°C). Transcript levels were measured from cells grown in five steady state oxygen levels (0, 0.5, 1, 2.8 and 20.9% O2), and from cells under conditions in which oxygen was introduced to anaerobic cultures or removed from cultures receiving oxygen. Results The expression pattern of the HXT gene family was distinct in cells grown under aerobic, hypoxic and anaerobic conditions. The transcription of HXT2, HXT4 and HXT5 was low when the oxygen concentration in the cultures was low, both under steady state and non-steady state conditions, whereas the expression of HXT6, HXT13 and HXT15/16 was higher in hypoxic than in fully aerobic or anaerobic conditions. None of the HXT genes showed higher transcript levels in strictly anaerobic conditions. Expression of HXT9, HXT14 and GAL2 was not detected under the culture conditions studied. Conclusion When oxygen becomes limiting in a glucose-limited chemostat cultivation, the glucose uptake rate per cell increases. However, the expression of none of the hexose transporter encoding genes was increased in anaerobic conditions. It thus seems that the decrease in the moderately low affinity uptake and consequently the relative increase of high affinity uptake may itself allow the higher specific glucose consumption rate to occur in anaerobic compared to aerobic conditions. PMID:18373847

  7. Calcium transport in bovine rumen epithelium as affected by luminal Ca concentrations and Ca sources

    PubMed Central

    Schröder, Bernd; Wilkens, Mirja R; Ricken, Gundula E; Leonhard-Marek, Sabine; Fraser, David R; Breves, Gerhard

    2015-01-01

    The quantitative role of different segments of the gastrointestinal tract for Ca absorption, the respective mechanisms, and their regulation are not fully identified for ruminants, that is, cattle. In different in vitro experiments the forestomach wall has been demonstrated to be a major site for active Ca absorption in sheep and goats. In order to further clarify the role of the bovine rumen for Ca transport with special attention to luminal Ca concentrations, its ionic form, and pH, electrophysiological and unidirectional flux rate measurements were performed with isolated bovine rumen epithelial tissues. For Ca flux studies (Jms, Jsm) in vitro Ussing chamber technique was applied. Standard RT-PCR method was used to characterize TRPV6 and PMCA1 as potential contributors to transepithelial active Ca transport. At Ca concentrations of 1.2 mmol L−1 on both sides of the tissues, Jms were higher than Jsm resulting under some conditions in significant Ca net flux rates (Jnet), indicating the presence of active Ca transport. In the absence of an electrical gradient, Jnet could significantly be stimulated in the presence of luminal short-chain fatty acids (SCFAs). Increasing the luminal Ca concentrations up to 11.2 mmol L−1 resulted in significant increases in Jms without influencing Jsm. Providing Ca in its form as respective chloride, formate, or propionate salts there was no significant effect on Jms. No transcripts specific for Ca channel TRPV6 could be demonstrated. Our results indicate different mechanisms for Ca absorption in bovine rumen as compared with those usually described for the small intestines. PMID:26564067

  8. Mapping of a genetic locus that affects glycerol 3-phosphate transport in Bacillus subtilis.

    PubMed Central

    Lindgren, V

    1978-01-01

    Two types of fosfomycin-resistant mutants of Bacillus subtilis were isolated. Mutants of the first type (GlpT mutants) were resistant to at least 200 microgram of fosfomycin per ml and failed to take up exogenous glycerol 3-phosphate. Mutants of the second type were resistant to lower concentrations of fosfomycin and transported glycerol-3-phosphate as efficiently as wild-type bacteria. The glpT mutations, but not the mutations in the second type of fosfomycin-resistant mutants, map in the cysA-aroI region of the B. subtilis chromosome. PMID:415047

  9. Factors Affecting the Corporate Decision-Making Process of Air Transport Manufacturers

    NASA Technical Reports Server (NTRS)

    Ollila, R. G.; Hill, J. D.; Noton, B. R.; Duffy, M. A.; Epstein, M. M.

    1976-01-01

    Fuel economy is a pivotal question influencing the future sale and utilization of commercial aircraft. The NASA Aircraft Energy Efficiency (ACEE) Program Office has a program intended to accelerate the readiness of advanced technologies for energy efficient aircraft. Because the decision to develop a new airframe or engine is a major financial hazard for manufacturers, it is important to know what factors influence the decision making process. A method is described for identifying and ranking individuals and organizations involved at each stage of commercial air transport development, and the barriers that must be overcome in adopting new technologies.

  10. From producer to consumer: greenhouse tomato quality as affected by variety, maturity stage at harvest, transport conditions, and supermarket storage.

    PubMed

    Verheul, Michèl J; Slimestad, Rune; Tjøstheim, Irene Holta

    2015-05-27

    Possible causes for differences in quality traits at the time of buying were studied in two widely different red tomato types. Three maturity stages were harvested from commercial greenhouses and transferred immediately to controlled environments simulating different storage, transport, and supermarket conditions. Results show significant differences in development of color, fruit firmness, contents of soluble solids (SSC), titratable acids (TTA), phenolics, and carotenoids from harvest to sale, as related to postharvest conditions. Fruit firmness, SSC, and TTA of vine-ripened red cherry tomatoes was 30, 55 and 11% higher than for those harvested at breakers and ripened to red. Temperature, light, UVC radiation, or ethylene during 4 days transport affected tomato quality traits, and differences persisted during 3 weeks of supermarket storage. Ethylene exposure gave a 3.7-fold increase in lycopene content in cherry tomatoes, whereas UVC hormesis revealed a 6-fold increase compared with the control. Results can be used to update recommendations concerning optimal handling.

  11. Processes affecting the transport of nitrogen in groundwater and factors related to slope position

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nitrate (NO3-) pollution of water resources has been a major problem for years, causing contaminated water supplies, harmful effects on human health, and widespread eutrophication of fresh water resources. The main objectives of this study were to: 1) understand the processes affecting NO3- transpor...

  12. Video instrumentation for radionuclide angiocardiography.

    NASA Technical Reports Server (NTRS)

    Kriss, J. P.

    1973-01-01

    Two types of videoscintiscopes for performing radioisotopic angiocardiography with a scintillation camera are described, and use of these instruments in performing clinical studies is illustrated. Radionuclide angiocardiography is a simple, quick and accurate procedure recommended as a screening test for patients with a variety of congenital and acquired cardiovascular lesions. When performed in conjunction with coronary arterial catheterization, dynamic radionuclide angiography may provide useful information about regional myocardial perfusion. Quantitative capabilities greatly enhance the potential of this diagnostic tool.

  13. TRANSPORT

    EPA Science Inventory

    Presentation outline: transport principles, effective solubility; gasoline composition; and field examples (plume diving).
    Presentation conclusions: MTBE transport follows from - phyiscal and chemical properties and hydrology. Field examples show: MTBE plumes > benzene plu...

  14. Geologic and societal factors affecting the international oceanic transport of aggregate

    USGS Publications Warehouse

    Langer, W.H.

    1995-01-01

    Crushed stone and sand and gravel are the two main sources of natural aggregate, and together comprise approximately half the volume and tonnage of mined material in the United States. Natural aggregate is a bulky, heavy material without special or unique properties, and it is commonly used near its source of production to minimize haulage cost. However, remoteness is no longer an absolute disqualifier for the production of aggregate. Today interstate aggregate routinely is shipped hundreds of kilometers by rail and barge. In addition, during 1992, the United States imported 1,317,000 metric tons of aggregate from Canada and 1,531,000 metric tons from Mexico. A number of ports on the Atlantic Coast and Gulf Coast of the United States receive imports of crushed stone from foreign sources for transport to various parts of the eastern United States. These areas either lack adequate supplies of aggregate or are augmenting their supplies because they have difficulties meeting current demand. These difficulties may include poor stone quality, environmental permitting problems, or transportation. Certain societal and geologic conditions of New York City and Philadelphia along the Atlantic Coast, and Tampa and New Orleans along the Gulf Coast, are discussed to demonstrate the different combinations of issues that contribute to the economic viability of importing crushed stone. ?? 1995 Oxford University Press.

  15. The Role of EPS in Microhydrology and Transport Processes Affecting Microbial Activity in Unsaturated Porous Media

    NASA Astrophysics Data System (ADS)

    Or, D.; Phutane, S.

    2005-12-01

    Extra-cellular Polymeric Substances (EPS) refers to biopolymers excreted and surrounding soil bacterial cells (and other biota) forming the scaffolding for colonies and serving a wide array of transport, nutrient entrapment, and mechanical functions. In essence, EPS is a porous matrix through which aqueous, gaseous and nutrient fluxes flow to supply the embedded bacterial cells. The large water holding capacity and retarded water loss rates of EPS dampens rapid fluctuations in hydration status of host porous medium which sustain higher diffusion fluxes than in surrounding porous medium, and shelters microbial cells from effect of rapid desiccation or rewetting. The morphology of EPS changes from an open well-hydrated bioweb to dense and highly cross-linked structure under dry conditions. Such morphological changes are accompanied by enhanced mechanical strength and retardation of water loss that provide additional time for physiological adaptation to desiccation. Additional capacitance results from the disparity in dynamic hydrological properties between EPS and soil that promotes water entrapment in EPS during rapid drainage. EPS may also trap dissolved nutrients that may be unevenly distributed and irregularly supplied in unsaturated environments, thereby increasing nutrient availability in the microhabitat and offsetting decreased supply by diffusion during drying. The remarkable transport and mechanical properties of EPS makes it an important stabilizing agent for soil aggregation and even minute amounts of EPS may significantly alter macroscopic hydrological properties of host porous medium.

  16. Simulation of runaway electrons, transport affected by J-TEXT resonant magnetic perturbation

    NASA Astrophysics Data System (ADS)

    Jiang, Z. H.; Wang, X. H.; Chen, Z. Y.; Huang, D. W.; Sun, X. F.; Xu, T.; Zhuang, G.

    2016-09-01

    The topology of a magnetic field and transport properties of runaway electrons can be changed by a resonant magnetic perturbation field. The J-TEXT magnetic topology can be effectively altered via static resonant magnetic perturbation (SRMP) and dynamic resonant magnetic perturbation (DRMP). This paper studies the effect of resonant magnetic perturbation (RMP) on the confinement of runaway electrons via simulating their drift orbits in the magnetic perturbation field and calculating the orbit losses for different runaway initial energies and different runaway electrons, initial locations. The model adopted is based on Hamiltonian guiding center equations for runaway electrons, and the J-TEXT magnetic turbulences and RMP are taken into account. The simulation indicates that the loss rate of runaway electrons is sensitive to the radial position of electrons. The loss of energetic runaway beam is dominated by the shrinkage of the confinement region. Outside the shrinkage region of the runaway electrons are lost rapidly. Inside the shrinkage region the runaway beam is confined very well and is less sensitive to the magnetic perturbation. The experimental result on the response of runaway transport to the application RMP indicates that the loss of runaway electrons is dominated by the shrinkage of the confinement region, other than the external magnetic perturbation.

  17. Intronless mRNA transport elements may affect multiple steps of pre-mRNA processing.

    PubMed Central

    Huang, Y; Wimler, K M; Carmichael, G G

    1999-01-01

    We have reported recently that a small element within the mouse histone H2a-coding region permits efficient cytoplasmic accumulation of intronless beta-globin cDNA transcripts. This sequence lowers the levels of spliced products from intron-containing constructs and can functionally replace Rev and the Rev-responsive element (RRE) in the nuclear export of unspliced HIV-1-related mRNAs. In work reported here, we further investigate the molecular mechanisms by which this element might work. We demonstrate here through both in vivo and in vitro assays that, in addition to promoting mRNA nuclear export, this element acts as a polyadenylation enhancer and as a potent inhibitor of splicing. Surprisingly, two other described intronless mRNA transport elements (from the herpes simplex virus thymidine kinase gene and hepatitis B virus) appear to function in a similar manner. These findings prompt us to suggest that a general feature of intronless mRNA transport elements might be a collection of phenotypes, including the inhibition of splicing and the enhancement of both polyadenylation and mRNA export. PMID:10075934

  18. Arbuscular mycorrhiza affects nickel translocation and expression of ABC transporter and metallothionein genes in Festuca arundinacea.

    PubMed

    Shabani, Leila; Sabzalian, Mohammad R; Mostafavi pour, Sodabeh

    2016-01-01

    Mycorrhizal fungi are key microorganisms for enhancing phytoremediation of soils contaminated with heavy metals. In this study, the effects of the arbuscular mycorrhizal fungus (AMF) Funneliformis mosseae (=Glomus mosseae) on physiological and molecular mechanisms involved in the nickel (Ni) tolerance of tall fescue (Festuca arundinacea = Schedonorus arundinaceus) were investigated. Nickel addition had a pronounced negative effect on tall fescue growth and photosynthetic pigment contents, as well as on AMF colonization. Phosphorus content increased markedly in mycorrhizal plants (M) compared to non-inoculated (NM) ones. However, no significant difference was observed in root carbohydrate content between AMF-inoculated and non-inoculated plants. For both M and NM plants, Ni concentrations in shoots and roots increased according to the addition of the metal into soil, but inoculation with F. mosseae led to significantly lower Ni translocation from roots to the aboveground parts compared to non-inoculated plants. ABC transporter and metallothionein transcripts accumulated to considerably higher levels in tall fescue plants colonized by F. mosseae than in the corresponding non-mycorrhizal plants. These results highlight the importance of mycorrhizal colonization in alleviating Ni-induced stress by reducing Ni transport from roots to shoots of tall fescue plants.

  19. MICROBIAL TRANSFORMATIONS OF RADIONUCLIDES RELEASED FROM NUCLEAR FUEL REPROCESSING PLANTS.

    SciTech Connect

    FRANCIS,A.J.

    2006-10-18

    Microorganisms can affect the stability and mobility of the actinides U, Pu, Cm, Am, Np, and the fission products Tc, I, Cs, Sr, released from nuclear fuel reprocessing plants. Under appropriate conditions, microorganisms can alter the chemical speciation, solubility and sorption properties and thus could increase or decrease the concentrations of radionuclides in solution and the bioavailability. Dissolution or immobilization of radionuclides is brought about by direct enzymatic action or indirect non-enzymatic action of microorganisms. Although the physical, chemical, and geochemical processes affecting dissolution, precipitation, and mobilization of radionuclides have been investigated, we have only limited information on the effects of microbial processes. The mechanisms of microbial transformations of the major and minor actinides and the fission products under aerobic and anaerobic conditions in the presence of electron donors and acceptors are reviewed.

  20. Anthropogenic radionuclides in the environment

    SciTech Connect

    Hu, Q; Weng, J; Wang, J

    2007-11-15

    Studies of radionuclides in the environment have entered a new era with the renaissance of nuclear energy and associated fuel reprocessing, geological disposal of high-level nuclear wastes, and concerns about national security with respect to nuclear non-proliferation. This work presents an overview of anthropogenic radionuclide contamination in the environment, as well as the salient geochemical behavior of important radionuclides. We first discuss the following major anthropogenic sources and current development that contribute to the radionuclide contamination of the environment: (1) nuclear weapons program; (2) nuclear weapons testing; (3) nuclear power plants; (4) commercial fuel reprocessing; (5) geological repository of high-level nuclear wastes, and (6) nuclear accidents. Then, we summarize the geochemical behavior for radionuclides {sup 99}Tc, {sup 129}I, and {sup 237}Np, because of their complex geochemical behavior, long half-lives, and presumably high mobility in the environment. Biogeochemical cycling and environment risk assessment must take into account speciation of these redox-sensitive radionuclides.

  1. Do ATP-binding cassette transporters cause pharmacoresistance in epilepsy? Problems and approaches in determining which antiepileptic drugs are affected.

    PubMed

    Löscher, Wolfgang; Luna-Tortós, Carlos; Römermann, Kerstin; Fedrowitz, Maren

    2011-01-01

    Resistance to multiple antiepileptic drugs (AEDs) is a common problem in epilepsy, affecting at least 30% of patients. One prominent hypothesis to explain this resistance suggests an inadequate penetration or excess efflux of AEDs across the blood - brain barrier (BBB) as a result of overexpressed efflux transporters such as P-glycoprotein (Pgp), the encoded product of the multidrug resistance- 1 (MDR1, ABCB1) gene. Pgp and MDR1 are markedly increased in epileptogenic brain tissue of patients with AED-resistant partial epilepsy and following seizures in rodent models of partial epilepsy. In rodent models, AED-resistant rats exhibit higher Pgp levels than responsive animals; increased Pgp expression is associated with lower brain levels of AEDs; and, most importantly, co-administration of Pgp inhibitors reverses AED resistance. Thus, it is reasonable to conclude that Pgp plays a significant role in mediating resistance to AEDs in rodent models of epilepsy - however, whether this phenomenon extends to at least some human refractory epilepsy remains unclear, particularly because it is still a matter of debate which AEDs, if any, are transported by human Pgp. The difficulty in determining which AEDs are substrates of human Pgp is mainly a consequence of the fact that AEDs are highly permeable compounds, which are not easily identified as Pgp substrates in in vitro models of the BBB, such as monolayer (Transwell(®)) efflux assays. By using a modified assay (concentration equilibrium transport assay; CETA), which minimizes the influence of high transcellular permeability, two groups have recently demonstrated that several major AEDs are transported by human Pgp. Importantly, it was demonstrated in these studies that Pgp-mediated transport highly depends on the AED concentration and may not be identified if concentrations below or above the therapeutic range are used. In addition to the efflux transporters, seizure-induced alterations in BBB integrity and activity of

  2. Hydrology and radionuclide migration program 1987 progress report

    SciTech Connect

    Marsh, K.V.

    1991-03-01

    This report presents results from the Lawrence Livermore National Laboratory's participation in the Hydrology and Radionuclide Migration Program at the Nevada Test Site (NTS) during the fiscal year 1987. The report discussed initial data from a new well (UE20n-1) drilled at the Cheshire site; presents a description of a proposed laboratory study of migration of colloids in fractured media; lists data collected during the drilling and initial sampling of UE20n-1; and describes a tentative proposal for work to be performed in FY88 by Lamont-Doherty Geological Observatory. Groundwater sampled from the new well at the Cheshire site contains tritium concentrations comparable to those measured in previous years from locations above and within the Cheshire cavity. This presence of tritium, as well as several other radionuclides, in a well 100 m away from the cavity region indicates transport of radionuclides, validates a proposed model of the flow path, and provides data on rates of groundwater flow. Previous work at the Cheshire site has shown that radionuclides are transported by colloids through fractured media. However, we have no data that can be used for predictive modeling, and existing theories are not applicable. While physical transport mechanisms of sub-micrometer colloids to defined mineral surfaces are well known, predictions based on well-defined conditions differ from experimental observations by orders of magnitude. The U.C. Berkeley group has designed a laboratory experiment to quantify colloid retention and permeability alteration by the retained colloids.

  3. Colonic epithelial ion transport is not affected in patients with diverticulosis

    PubMed Central

    Osbak, Philip S; Bindslev, Niels; Poulsen, Steen S; Kaltoft, Nicolai; Tilotta, Maria C; Hansen, Mark B

    2007-01-01

    Background Colonic diverticular disease is a bothersome condition with an unresolved pathogenesis. It is unknown whether a neuroepithelial dysfunction is present. The aim of the study was two-fold; (1) to investigate colonic epithelial ion transport in patients with diverticulosis and (2) to adapt a miniaturized Modified Ussing Air-Suction (MUAS) chamber for colonic endoscopic biopsies. Methods Biopsies were obtained from the sigmoid part of the colon. 86 patients were included. All patients were referred for colonoscopy on suspicion of neoplasia and they were without pathological findings at colonoscopy (controls) except for diverticulosis in 22 (D-patients). Biopsies were mounted in MUAS chambers with an exposed area of 5 mm2. Electrical responses to various stimulators and inhibitors of ion transport were investigated together with histological examination. The MUAS chamber was easy to use and reproducible data were obtained. Results Median basal short circuit current (SCC) was 43.8 μA·cm-2 (0.8 – 199) for controls and 59.3 μA·cm-2 (3.0 – 177.2) for D-patients. Slope conductance was 77.0 mS·cm-2 (18.6 – 204.0) equal to 13 Ω·cm2 for controls and 96.6 mS·cm-2 (8.4 – 191.4) equal to 10.3 Ω·cm2 for D-patients. Stimulation with serotonin, theophylline, forskolin and carbachol induced increases in SCC in a range of 4.9 – 18.6 μA·cm-2, while inhibition with indomethacin, bumetanide, ouabain and amiloride decreased SCC in a range of 6.5 – 27.4 μA·cm-2, and all with no significant differences between controls and D-patients. Histological examinations showed intact epithelium and lamina propria before and after mounting for both types of patients. Conclusion We conclude that epithelial ion transport is not significantly altered in patients with diverticulosis and that the MUAS chamber can be adapted for studies of human colonic endoscopic biopsies. PMID:17888183

  4. The outlook for aeronautics, 1980 - 2000 - Study report. [trends affecting civil air transportation and defense

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Trends in civil and military aviation in the period 1980-2000 are examined in terms of the role that NASA should play in aeronautical research and development during this period. Factors considered include the pattern of industry and government relationships, the character of the aircraft to be developed, and the technology advances that will be required as well as demographic, economic, and social factors. Trends are expressed in terms of the most probable developments in civil air transportation and air defense and several characteristically different directions for future development are defined. The longer term opportunities created by developments in air transporation extending into the next century are also examined. Within this framework, a preferred NASA role and a preferred set of objectives are formulated for the research and technology which should be undertaken by NASA during the period 1976-1985.

  5. Parental vitamin deficiency affects the embryonic gene expression of immune-, lipid transport- and apolipoprotein genes

    PubMed Central

    Skjærven, Kaja H.; Jakt, Lars Martin; Dahl, John Arne; Espe, Marit; Aanes, Håvard; Hamre, Kristin; Fernandes, Jorge M. O.

    2016-01-01

    World Health Organization is concerned for parental vitamin deficiency and its effect on offspring health. This study examines the effect of a marginally dietary-induced parental one carbon (1-C) micronutrient deficiency on embryonic gene expression using zebrafish. Metabolic profiling revealed a reduced 1-C cycle efficiency in F0 generation. Parental deficiency reduced the fecundity and a total of 364 genes were differentially expressed in the F1 embryos. The upregulated genes (53%) in the deficient group were enriched in biological processes such as immune response and blood coagulation. Several genes encoding enzymes essential for the 1-C cycle and for lipid transport (especially apolipoproteins) were aberrantly expressed. We show that a parental diet deficient in micronutrients disturbs the expression in descendant embryos of genes associated with overall health, and result in inherited aberrations in the 1-C cycle and lipid metabolism. This emphasises the importance of parental micronutrient status for the health of the offspring. PMID:27731423

  6. Parental vitamin deficiency affects the embryonic gene expression of immune-, lipid transport- and apolipoprotein genes

    NASA Astrophysics Data System (ADS)

    Skjærven, Kaja H.; Jakt, Lars Martin; Dahl, John Arne; Espe, Marit; Aanes, Håvard; Hamre, Kristin; Fernandes, Jorge M. O.

    2016-10-01

    World Health Organization is concerned for parental vitamin deficiency and its effect on offspring health. This study examines the effect of a marginally dietary-induced parental one carbon (1-C) micronutrient deficiency on embryonic gene expression using zebrafish. Metabolic profiling revealed a reduced 1-C cycle efficiency in F0 generation. Parental deficiency reduced the fecundity and a total of 364 genes were differentially expressed in the F1 embryos. The upregulated genes (53%) in the deficient group were enriched in biological processes such as immune response and blood coagulation. Several genes encoding enzymes essential for the 1-C cycle and for lipid transport (especially apolipoproteins) were aberrantly expressed. We show that a parental diet deficient in micronutrients disturbs the expression in descendant embryos of genes associated with overall health, and result in inherited aberrations in the 1-C cycle and lipid metabolism. This emphasises the importance of parental micronutrient status for the health of the offspring.

  7. Initial Sediment Transport Model of the Mining-Affected Aries River Basin, Romania

    USGS Publications Warehouse

    Friedel, Michael J.; Linard, Joshua I.

    2008-01-01

    The Romanian government is interested in understanding the effects of existing and future mining activities on long-term dispersal, storage, and remobilization of sediment-associated metals. An initial Soil and Water Assessment Tool (SWAT) model was prepared using available data to evaluate hypothetical failure of the Valea Sesei tailings dam at the Rosia Poieni mine in the Aries River basin. Using the available data, the initial Aries River Basin SWAT model could not be manually calibrated to accurately reproduce monthly streamflow values observed at the Turda gage station. The poor simulation of the monthly streamflow is attributed to spatially limited soil and precipitation data, limited constraint information due to spatially and temporally limited streamflow measurements, and in ability to obtain optimal parameter values when using a manual calibration process. Suggestions to improve the Aries River basin sediment transport model include accounting for heterogeneity in model input, a two-tier nonlinear calibration strategy, and analysis of uncertainty in predictions.

  8. Long-term transport behavior of psychoactive compounds in sewage-affected groundwater

    NASA Astrophysics Data System (ADS)

    Nham, Hang Thuy Thi; Greskowiak, Janek; Hamann, Enrico; Meffe, Raffaella; Hass, Ulrike; Massmann, Gudrun

    2016-11-01

    The present study provides a model-based characterization of the long-term transport behavior of five psychoactive compounds (meprobamate, pyrithyldione, primidone, phenobarbital and phenylethylmalonamide) introduced into groundwater via sewage irrigation in Berlin, Germany. Compounds are still present in the groundwater despite the sewage farm closure in the year 1980. Due to the limited information on (i) compound concentrations in the source water and (ii) substance properties, a total of 180 cross-sectional model realizations for each compound were carried out, covering a large range of possible parameter combinations. Results were compared with the present-day contamination patterns in the aquifer and the most likely scenarios were identified based on a number of model performance criteria. The simulation results show that (i) compounds are highly persistent under the present field conditions, and (ii) sorption is insignificant. Thus, back-diffusion from low permeability zones appears as the main reason for the compound retardation.

  9. Ocean plankton. Environmental characteristics of Agulhas rings affect interocean plankton transport.

    PubMed

    Villar, Emilie; Farrant, Gregory K; Follows, Michael; Garczarek, Laurence; Speich, Sabrina; Audic, Stéphane; Bittner, Lucie; Blanke, Bruno; Brum, Jennifer R; Brunet, Christophe; Casotti, Raffaella; Chase, Alison; Dolan, John R; d'Ortenzio, Fabrizio; Gattuso, Jean-Pierre; Grima, Nicolas; Guidi, Lionel; Hill, Christopher N; Jahn, Oliver; Jamet, Jean-Louis; Le Goff, Hervé; Lepoivre, Cyrille; Malviya, Shruti; Pelletier, Eric; Romagnan, Jean-Baptiste; Roux, Simon; Santini, Sébastien; Scalco, Eleonora; Schwenck, Sarah M; Tanaka, Atsuko; Testor, Pierre; Vannier, Thomas; Vincent, Flora; Zingone, Adriana; Dimier, Céline; Picheral, Marc; Searson, Sarah; Kandels-Lewis, Stefanie; Acinas, Silvia G; Bork, Peer; Boss, Emmanuel; de Vargas, Colomban; Gorsky, Gabriel; Ogata, Hiroyuki; Pesant, Stéphane; Sullivan, Matthew B; Sunagawa, Shinichi; Wincker, Patrick; Karsenti, Eric; Bowler, Chris; Not, Fabrice; Hingamp, Pascal; Iudicone, Daniele

    2015-05-22

    Agulhas rings provide the principal route for ocean waters to circulate from the Indo-Pacific to the Atlantic basin. Their influence on global ocean circulation is well known, but their role in plankton transport is largely unexplored. We show that, although the coarse taxonomic structure of plankton communities is continuous across the Agulhas choke point, South Atlantic plankton diversity is altered compared with Indian Ocean source populations. Modeling and in situ sampling of a young Agulhas ring indicate that strong vertical mixing drives complex nitrogen cycling, shaping community metabolism and biogeochemical signatures as the ring and associated plankton transit westward. The peculiar local environment inside Agulhas rings may provide a selective mechanism contributing to the limited dispersal of Indian Ocean plankton populations into the Atlantic.

  10. Geomorphic control of radionuclide diffusion in desert soils

    USGS Publications Warehouse

    Pelletier, J.D.; Harrington, C.D.; Whitney, J.W.; Cline, M.; DeLong, S.B.; Keating, G.; Ebert, T.K.

    2005-01-01

    Diffusion is a standard model for the vertical migration of radionuclides in soil profiles. Here we show that diffusivity values inferred from fallout 137CS profiles in soils on the Fortymile Wash alluvial fan, Nye County, Nevada, have a strong inverse correlation with the age of the geomorphic surface. This result suggests that radionuclide-bound particles are predominantly transported by infiltration rather than by bulk-mixing processes such as wetting/ drying, freeze/thaw, and bioturbation. Our results provide a preliminary basis for using soil-geomorphic mapping, point-based calibration data, and the diffusion model to predict radionuclide trans desert soils within a pedotransfer-function approach. Copyright 2005 by the American Geophysical Union.

  11. Enkephalin affects ion transport via the enteric nervous system in guinea-pig ileum.

    PubMed

    Schulzke, J D; Fromm, M; Riecken, E O; Reutter, W

    1990-04-01

    The endogenous opioid enkephalin drives ion transport towards absorption. To determine the site and mechanism of this effect, fractionated stripping of guinea-pig ileum was carried out. The muscularis propria, including myenteric plexus, was removed by partial stripping. The submucosa, including the submucosal plexus, plus the muscularis mucosae were removed by total stripping. For binding studies, epithelial cells were removed by the method of Weiser leaving the lamina propria mucosae with the mucosal plexus. Radio-receptor-assay with (3H)2-D-ala-5-D-leu-enkephalin revealed enkephalin binding sites in the submucosa plus muscularis mucosae (KD = 3.6 nmol l-1; Vmax = 7.3 fmol mg-1) and in the lamina propria mucosae (KD = 4.2 nmol l-1; Vmax = 5.1 fmol mg-1. The binding was stereospecific in both layers. No binding was detected on epithelial cells. In the Ussing chamber, partially stripped ileum exhibited spontaneous ISC which was abolished by addition of tetrodotoxin (TTX) or by total stripping indicating that this ISC was neuronally stimulated by the submucosal plexus. Electrogenic chloride secretion was identified as contributing to this ISC, since the TTX-sensitive part of ISC in the partially stripped ileum was lacking in Cl- and HCO3-free medium, reappeared after addition of Cl consistent with Michaelis-Menten kinetics (Km = 19 nmol l-1) and was reversed by serosal addition of bumetanide. In addition, enkephalin increased electroneutral NaCl-absorption as obtained by Na- and Cl-flux measurements. Enkephalin decreased this spontaneous neuronally stimulated electrogenic Cl-secretion in the partially stripped ileum, but had no effect in totally stripped ileum if ISC was stimulated at the cellular level by theophylline or PGE1. We conclude that ganglia located in the submucosal plexus regulate intestinal ion transport. Enkephalin acts by presynaptic inhibition via receptors on these neurons in the submucosa and/or via receptors on their neurites in the lamina

  12. Soil structure, colloids, and chemical transport as affected by short-term reducing conditions: a laboratory study

    NASA Astrophysics Data System (ADS)

    de-Campos, A. B.; Mamedov, A. I.; Huang, C.; Wagner, L. E.

    2008-12-01

    Upland soils in the Midwestern US often undergo reducing conditions when soils are temporally flooded during the spring and remain water saturated for days or weeks. Short-term reducing conditions change the chemistry of the soil and may affect soil structure and solution chemical transport. The effects of short-term reducing conditions on chemical and physical properties of the soils, colloids, and associated chemical/nutrients transport are still not well understood and was the objective of our study. A biogeochemical reactor was built to achieve reducing conditions. Three cultivated and three uncultivated soils with different organic carbon contents were incubated in the reactor for 1 hour and 3 days under anaerobic conditions. Effects of the redox state on soil structure (pore size distribution) and drainable porosity, colloids mobility, and chemical transport were determined using high energy moisture characteristic and analytical methods. After each treatment, the soil solution was collected for redox potential (Eh), pH, and electrical conductivity (EC) measurements, and chemical analysis of metals (Ca, Mg, K), nutrients (N, P), and dissolved organic carbon. Strongly reducing conditions were achieved after 3 days of incubation and were followed by a decrease in soil porosity and an increase in pH, EC, clay dispersion, swelling, colloids mobility, and associated chemical transport. The trend for each soil depended on their initial structural stability and chemical properties. The structure of cultivated soils and the leaching of nutrients and carbon from uncultivated soils were more sensitive to the redox state. A strong correlation was found between changes in Eh and drainable porosity. The role of short-term reducing conditions on changes in redox sensitive elements, organic matter decomposition, pH, and EC and their influence on soil structure and soil particles or colloids/chemical transport for both soil groups are discussed in the paper. This study

  13. Quantitative Modeling of Cerenkov Light Production Efficiency from Medical Radionuclides

    PubMed Central

    Beattie, Bradley J.; Thorek, Daniel L. J.; Schmidtlein, Charles R.; Pentlow, Keith S.; Humm, John L.; Hielscher, Andreas H.

    2012-01-01

    There has been recent and growing interest in applying Cerenkov radiation (CR) for biological applications. Knowledge of the production efficiency and other characteristics of the CR produced by various radionuclides would help in accessing the feasibility of proposed applications and guide the choice of radionuclides. To generate this information we developed models of CR production efficiency based on the Frank-Tamm equation and models of CR distribution based on Monte-Carlo simulations of photon and β particle transport. All models were validated against direct measurements using multiple radionuclides and then applied to a number of radionuclides commonly used in biomedical applications. We show that two radionuclides, Ac-225 and In-111, which have been reported to produce CR in water, do not in fact produce CR directly. We also propose a simple means of using this information to calibrate high sensitivity luminescence imaging systems and show evidence suggesting that this calibration may be more accurate than methods in routine current use. PMID:22363636

  14. A Bayesian Algorithm for Assessing Uncertainty in Radionuclide Source Terms

    NASA Astrophysics Data System (ADS)

    Robins, Peter

    2015-04-01

    Inferring source term parameters for a radionuclide release is difficult, due to the large uncertainties in forward dispersion modelling as a consequence of imperfect knowledge pertaining to wind vector fields and turbulent diffusion in the Earth's atmosphere. Additional sources of error include the radionuclide measurements obtained from sensors. These measurements may either be subject to random fluctuations or are simple indications that the true, unobserved quantity is below a detection limit. Consequent large reconstruction uncertainties can render a "best" estimate meaningless. A Markov Chain Monte Carlo (MCMC) Bayesian Algorithm is presented that attempts to account for uncertainties in atmospheric transport modelling and radionuclide sensor measurements to quantify uncertainties in radionuclide release source term parameters. Prior probability distributions are created for likely release locations at existing nuclear facilities and seismic events. Likelihood models are constructed using CTBTO adjoint modelling output and probability distributions of sensor response. Samples from the resulting multi-isotope source term parameters posterior probability distribution are generated that can be used to make probabilistic statements about the source term. Examples are given of marginal probability distributions obtained from simulated sensor data. The consequences of errors in numerical weather prediction wind fields are demonstrated with a reconstruction of the Fukushima nuclear reactor accident from International Monitoring System radionuclide particulate sensor data.

  15. Comparative Measures of Radionuclide Containment in the Crystalline Geophere

    SciTech Connect

    Cvetkovic, V.; Painter, S.; Selroos, J.O.

    2002-11-15

    A probabilistic model for assessing the capacity of a fractured crystalline rock volume to contain radionuclides is developed. The rock volume is viewed as a network of discrete fractures through which radionuclides are transported by flowing water. Diffusive mass transfer between the open fractures and the stagnant water in the pore space of the rock matrix allow radionuclides access to mineral grains where physical and chemical processes - collectively known as sorption - can retain radionuclides. A stochastic Lagrangian framework is adopted to compute the probability that a radionuclide particle will be retained by the rock, i.e., the probability that it will decay before being released from the rock volume. A dimensionless quantity referred to as the 'containment index' is related to this probability and proposed as a suitable measure for comparing different rock volumes; such a comparative measure may be needed, for example, in a site selection program for geological radioactive waste disposal. The probabilistic solution of the transport problem is based on the statistics of two Lagrangian variables: {tau}, the travel time of an imaginary tracer moving with the flowing water, and {beta}, a suitably normalized surface area available for retention. Statistics of {tau} and {beta} may be computed numerically using site-specific discrete fracture network simulations. Fracture data from the well-characterized Aespoe Hard Rock Laboratory site in southern Sweden are used to illustrate the implementation of the proposed containment index for six radionuclides ({sup 126}Sn, {sup 129}I, {sup 135}Cs, {sup 237}Np, {sup 239}Pu, and {sup 79}Se). It is found that fractures of small aperture imply prolonged travel times and hence long tails in both beta and tau. This, in turn, enhances retention and is favorable from a safety assessment perspective.

  16. Staufen Recruitment into Stress Granules Does Not Affect Early mRNA Transport in Oligodendrocytes

    PubMed Central

    Thomas, María G.; Tosar, Leandro J. Martinez; Loschi, Mariela; Pasquini, Juana M.; Correale, Jorge; Kindler, Stefan; Boccaccio, Graciela L.

    2005-01-01

    Staufen is a conserved double-stranded RNA-binding protein required for mRNA localization in Drosophila oocytes and embryos. The mammalian homologues Staufen 1 and Staufen 2 have been implicated in dendritic RNA targeting in neurons. Here we show that in rodent oligodendrocytes, these two proteins are present in two independent sets of RNA granules located at the distal myelinating processes. A third kind of RNA granules lacks Staufen and contains major myelin mRNAs. Myelin Staufen granules associate with microfilaments and microtubules, and their subcellular distribution is affected by polysome-disrupting drugs. Under oxidative stress, both Staufen 1 and Staufen 2 are recruited into stress granules (SGs), which are stress-induced organelles containing transiently silenced messengers. Staufen SGs contain the poly(A)-binding protein (PABP), the RNA-binding proteins HuR and TIAR, and small but not large ribosomal subunits. Staufen recruitment into perinuclear SGs is paralleled by a similar change in the overall localization of polyadenylated RNA. Under the same conditions, the distribution of recently transcribed and exported mRNAs is not affected. Our results indicate that Staufen 1 and Staufen 2 are novel and ubiquitous SG components and suggest that Staufen RNPs are involved in repositioning of most polysomal mRNAs, but not of recently synthesized transcripts, during the stress response. PMID:15525674

  17. Information technology and road transport industry: how does IT affect the lorry driver?

    PubMed

    de Croon, Einar M; Kuijer, P Paul F M; Broersen, Jake P J; Frings-Dresen, Monique H W

    2004-07-01

    A quasi-experimental design was used to study the effect of on board computer-systems (OBC-systems) on the Dutch lorry drivers' psychosocial work environment (i.e., control and demands) and coinciding mental health (i.e., need for recovery after work) and job attitudes (i.e., organisational commitment). The intervention group (n = 26) started working with an OBC-system between 1998 and 2000 and was compared with two matched reference groups (n = 26 in both groups). All participants were from a cohort of 650 drivers who participated in a prospective study on occupational stress and health. All outcome variables were quantified by standardised and validated questionnaires. Results showed that the application of OBC-systems negatively affected the drivers' job control and organisational commitment. However, OBC-systems did not influence the drivers' psychological job demands and need for recovery after work. Accordingly, it is concluded that the application of OBC-systems negatively affects the lorry driver's psychosocial work environment and job attitudes.

  18. Characterizing multiple timescales of stream and storage zone interaction that affect solute fate and transport in streams

    USGS Publications Warehouse

    Choi, J.; Harvey, J.W.; Conklin, M.H.

    2000-01-01

    The fate of contaminants in streams and rivers is affected by exchange and biogeochemical transformation in slowly moving or stagnant flow zones that interact with rapid flow in the main channel. In a typical stream, there are multiple types of slowly moving flow zones in which exchange and transformation occur, such as stagnant or recirculating surface water as well as subsurface hyporheic zones. However, most investigators use transport models with just a single storage zone in their modeling studies, which assumes that the effects of multiple storage zones can be lumped together. Our study addressed the following question: Can a single-storage zone model reliably characterize the effects of physical retention and biogeochemical reactions in multiple storage zones? We extended an existing stream transport model with a single storage zone to include a second storage zone. With the extended model we generated 500 data sets representing transport of nonreactive and reactive solutes in stream systems that have two different types of storage zones with variable hydrologic conditions. The one storage zone model was tested by optimizing the lumped storage parameters to achieve a best fit for each of the generated data sets. Multiple storage processes were categorized as possessing I, additive; II, competitive; or III, dominant storage zone characteristics. The classification was based on the goodness of fit of generated data sets, the degree of similarity in mean retention time of the two storage zones, and the relative distributions of exchange flux and storage capacity between the two storage zones. For most cases (> 90%) the one storage zone model described either the effect of the sum of multiple storage processes (category I) or the dominant storage process (category III). Failure of the one storage zone model occurred mainly for category II, that is, when one of the storage zones had a much longer mean retention time (t(s) ratio > 5.0) and when the dominance of

  19. Clinically used selective estrogen receptor modulators affect different steps of macrophage-specific reverse cholesterol transport.

    PubMed

    Fernández-Suárez, María E; Escolà-Gil, Joan C; Pastor, Oscar; Dávalos, Alberto; Blanco-Vaca, Francisco; Lasunción, Miguel A; Martínez-Botas, Javier; Gómez-Coronado, Diego

    2016-09-07

    Selective estrogen receptor modulators (SERMs) are widely prescribed drugs that alter cellular and whole-body cholesterol homeostasis. Here we evaluate the effect of SERMs on the macrophage-specific reverse cholesterol transport (M-RCT) pathway, which is mediated by HDL. Treatment of human and mouse macrophages with tamoxifen, raloxifene or toremifene induced the accumulation of cytoplasmic vesicles of acetyl-LDL-derived free cholesterol. The SERMs impaired cholesterol efflux to apolipoprotein A-I and HDL, and lowered ABCA1 and ABCG1 expression. These effects were not altered by the antiestrogen ICI 182,780 nor were they reproduced by 17β-estradiol. The treatment of mice with tamoxifen or raloxifene accelerated HDL-cholesteryl ester catabolism, thereby reducing HDL-cholesterol concentrations in serum. When [(3)H]cholesterol-loaded macrophages were injected into mice intraperitoneally, tamoxifen, but not raloxifene, decreased the [(3)H]cholesterol levels in serum, liver and feces. Both SERMs downregulated liver ABCG5 and ABCG8 protein expression, but tamoxifen reduced the capacity of HDL and plasma to promote macrophage cholesterol efflux to a greater extent than raloxifene. We conclude that SERMs interfere with intracellular cholesterol trafficking and efflux from macrophages. Tamoxifen, but not raloxifene, impair M-RCT in vivo. This effect is primarily attributable to the tamoxifen-mediated reduction of the capacity of HDL to promote cholesterol mobilization from macrophages.

  20. Clinically used selective estrogen receptor modulators affect different steps of macrophage-specific reverse cholesterol transport

    PubMed Central

    Fernández-Suárez, María E.; Escolà-Gil, Joan C.; Pastor, Oscar; Dávalos, Alberto; Blanco-Vaca, Francisco; Lasunción, Miguel A.; Martínez-Botas, Javier; Gómez-Coronado, Diego

    2016-01-01

    Selective estrogen receptor modulators (SERMs) are widely prescribed drugs that alter cellular and whole-body cholesterol homeostasis. Here we evaluate the effect of SERMs on the macrophage-specific reverse cholesterol transport (M-RCT) pathway, which is mediated by HDL. Treatment of human and mouse macrophages with tamoxifen, raloxifene or toremifene induced the accumulation of cytoplasmic vesicles of acetyl-LDL-derived free cholesterol. The SERMs impaired cholesterol efflux to apolipoprotein A-I and HDL, and lowered ABCA1 and ABCG1 expression. These effects were not altered by the antiestrogen ICI 182,780 nor were they reproduced by 17β-estradiol. The treatment of mice with tamoxifen or raloxifene accelerated HDL-cholesteryl ester catabolism, thereby reducing HDL-cholesterol concentrations in serum. When [3H]cholesterol-loaded macrophages were injected into mice intraperitoneally, tamoxifen, but not raloxifene, decreased the [3H]cholesterol levels in serum, liver and feces. Both SERMs downregulated liver ABCG5 and ABCG8 protein expression, but tamoxifen reduced the capacity of HDL and plasma to promote macrophage cholesterol efflux to a greater extent than raloxifene. We conclude that SERMs interfere with intracellular cholesterol trafficking and efflux from macrophages. Tamoxifen, but not raloxifene, impair M-RCT in vivo. This effect is primarily attributable to the tamoxifen-mediated reduction of the capacity of HDL to promote cholesterol mobilization from macrophages. PMID:27601313

  1. Desiccation of sediments affects assimilate transport within aquatic plants and carbon transfer to microorganisms.

    PubMed

    von Rein, I; Kayler, Z E; Premke, K; Gessler, A

    2016-11-01

    With the projected increase in drought duration and intensity in future, small water bodies, and especially the terrestrial-aquatic interfaces, will be subjected to longer dry periods with desiccation of the sediment. Drought effects on the plant-sediment microorganism carbon continuum may disrupt the tight linkage between plants and microbes which governs sediment carbon and nutrient cycling, thus having a potential negative impact on carbon sequestration of small freshwater ecosystems. However, research on drought effects on the plant-sediment carbon transfer in aquatic ecosystems is scarce. We therefore exposed two emergent aquatic macrophytes, Phragmites australis and Typha latifolia, to a month-long summer drought in a mesocosm experiment. We followed the fate of carbon from leaves to sediment microbial communities with (13) CO2 pulse labelling and microbial phospholipid-derived fatty acid (PLFA) analysis. We found that drought reduced the total amount of carbon allocated to stem tissues but did not delay the transport. We also observed an increase in accumulation of (13) C-labelled sugars in roots and found a reduced incorporation of (13) C into the PLFAs of sediment microorganisms. Drought induced a switch in plant carbon allocation priorities, where stems received less new assimilates leading to reduced starch reserves whilst roots were prioritised with new assimilates, suggesting their use for osmoregulation. There were indications that the reduced carbon transfer from roots to microorganisms was due to the reduction of microbial activity via direct drought effects rather than to a decrease in root exudation or exudate availability.

  2. Some factors affecting phosphate transport in a perfused rat heart preparation.

    PubMed Central

    Medina, G; Illingworth, J

    1980-01-01

    Pi uptake by a perfused rat heart preparation did not require the presence of any other permeant anion, but was markedly dependent on the extracellular Na+ concentration and accelerated when tissue oxygenation was inadequate. Pi efflux was also independent of other permeant anions, but apparently varied with the intracellular Na+ concentration. Cardiac Pi efflux was not sensitive to a number of inhibitors that clock Cl- movement in heart and other tissues. Both uptake and efflux apparently proceed via a reversible electroneutral co-transport system linked to the transmembrane Na+ gradient. Pi uptake was independent of cardiac work load, but the efflux rate was sharply accelerated after an increase in aortic pressure development, with a slow return towards basal values during sustained periods of high work output. An inverted biphasic effect on the efflux rate was observed after a reduction in cardiac work load. Mild hypoxia and respiratory and metabolic acidosis each resulted in a transient acceleration of Pi efflux followed by a return towards basal values during prolonged exposure to the stimulus, whereas respiratory and metabolic alkalosis produced a similar but inverted response. The origin of these phasic effects on Pi efflux remains to be identified at present. PMID:7396864

  3. How non-adiabatic passing electron layers of linear microinstabilities affect turbulent transport

    NASA Astrophysics Data System (ADS)

    Dominski, J.; Brunner, S.; Görler, T.; Jenko, F.; Told, D.; Villard, L.

    2015-06-01

    The response of passing electrons in ion temperature gradient and trapped electron mode microturbulence regimes is investigated in tokamak geometry making use of the flux-tube version of the gyrokinetic code GENE. Results are obtained using two different electron models, fully kinetic and hybrid in which passing particles are forced to respond adiabatically, while trapped are handled kinetically. Comparing linear eigenmodes obtained with these two models enables to systematically isolate fine radial structures located at corresponding mode rational surfaces, clearly resulting from the non-adiabatic passing-electron response. Non-linear simulations show that these fine structures on the non-axisymmetric modes survive in the turbulent phase. Furthermore, through non-linear coupling to axisymmetric modes, they induce radial modulations in the effective profiles of density, ion/electron temperature, and E × B shearing rate. Finally, the passing-electron channel is shown to significantly contribute to the transport levels, at least in our ion temperature gradient case. Also shown is that the passing electrons significantly influence the E × B saturation mechanism of turbulence fluxes.

  4. Hydrostatic pressure affects selective tidal stream transport in the North Sea brown shrimp (Crangon crangon).

    PubMed

    Tielmann, Moritz; Reiser, Stefan; Hufnagl, Marc; Herrmann, Jens-Peter; Eckardt, André; Temming, Axel

    2015-10-01

    The brown shrimp (Crangon crangon) is a highly abundant invertebrate in the North Sea, with its life cycle stages ranging from deep offshore spawning to shallow onshore nursery areas. To overcome the long distances between these two habitats, brown shrimp are suspected to use selective tidal stream transport (STST), moving with the cyclic tide currents towards their preferred water depths. However, it is not known which stimulus actually triggers STST behavior in brown shrimp. In this work, we determined the influence of different hyperbaric pressures on STST behavior of juvenile brown shrimp. Brown shrimp activity was recorded in a hyperbaric pressure chamber that supplied constant and dynamic pressure conditions simulating different depths, with and without a tidal cycle. Subsequent wavelet and Fourier analysis were performed to determine the periodicity in the activity data. The results of the experiments show that STST behavior in brown shrimp varies with pressure and therefore with depth. We further show that STST behavior can be initiated by cyclic pressure changes. However, an interaction with one or more other environmental triggers remains possible. Furthermore, a security ebb-tide activity was identified that may serve to avoid potential stranding in shallow waters and is 'remembered' by shrimp for about 1.5 days without contact with tidal triggers.

  5. Surface charge accumulation of particles containing radionuclides in open air.

    PubMed

    Kim, Yong-ha; Yiacoumi, Sotira; Tsouris, Costas

    2015-05-01

    Radioactivity can induce charge accumulation on radioactive particles. However, electrostatic interactions caused by radioactivity are typically neglected in transport modeling of radioactive plumes because it is assumed that ionizing radiation leads to charge neutralization. The assumption that electrostatic interactions caused by radioactivity are negligible is evaluated here by examining charge accumulation and neutralization on particles containing radionuclides in open air. A charge-balance model is employed to predict charge accumulation on radioactive particles. It is shown that particles containing short-lived radionuclides can be charged with multiple elementary charges through radioactive decay. The presence of radioactive particles can significantly modify the particle charge distribution in open air and yield an asymmetric bimodal charge distribution, suggesting that strong electrostatic particle interactions may occur during short- and long-range transport of radioactive particles. Possible effects of transported radioactive particles on electrical properties of the local atmosphere are reported. The study offers insight into transport characteristics of airborne radionuclides. Results are useful in atmospheric transport modeling of radioactive plumes.

  6. Surface charge accumulation of particles containing radionuclides in open air

    SciTech Connect

    Kim, Yong-ha; Yiacoumi, Sotira; Tsouris, Costas

    2015-05-01

    Radioactivity can induce charge accumulation on radioactive particles. But, electrostatic interactions caused by radioactivity are typically neglected in transport modeling of radioactive plumes because it is assumed that ionizing radiation leads to charge neutralization. The assumption that electrostatic interactions caused by radioactivity are negligible is evaluated here by examining charge accumulation and neutralization on particles containing radionuclides in open air. Moreover, a charge-balance model is employed to predict charge accumulation on radioactive particles. It is shown that particles containing short-lived radionuclides can be charged with multiple elementary charges through radioactive decay. The presence of radioactive particles can significantly modify the particle charge distribution in open air and yield an asymmetric bimodal charge distribution, suggesting that strong electrostatic particle interactions may occur during short- and long-range transport of radioactive particles. Possible effects of transported radioactive particles on electrical properties of the local atmosphere are reported. Our study offers insight into transport characteristics of airborne radionuclides. Results are useful in atmospheric transport modeling of radioactive plumes.

  7. Surface charge accumulation of particles containing radionuclides in open air

    DOE PAGES

    Kim, Yong-ha; Yiacoumi, Sotira; Tsouris, Costas

    2015-05-01

    Radioactivity can induce charge accumulation on radioactive particles. But, electrostatic interactions caused by radioactivity are typically neglected in transport modeling of radioactive plumes because it is assumed that ionizing radiation leads to charge neutralization. The assumption that electrostatic interactions caused by radioactivity are negligible is evaluated here by examining charge accumulation and neutralization on particles containing radionuclides in open air. Moreover, a charge-balance model is employed to predict charge accumulation on radioactive particles. It is shown that particles containing short-lived radionuclides can be charged with multiple elementary charges through radioactive decay. The presence of radioactive particles can significantly modify themore » particle charge distribution in open air and yield an asymmetric bimodal charge distribution, suggesting that strong electrostatic particle interactions may occur during short- and long-range transport of radioactive particles. Possible effects of transported radioactive particles on electrical properties of the local atmosphere are reported. Our study offers insight into transport characteristics of airborne radionuclides. Results are useful in atmospheric transport modeling of radioactive plumes.« less

  8. CRRIS: a methodology for assessing the impact of airborne radionuclide releases

    SciTech Connect

    Baes, C.F. III; Miller, C.W.

    1983-01-01

    The Computerized Radiological Risk Investigation System (CRRIS) consists of six fully integrated computer codes which calculate environmental transport and resulting doses and risks to individuals or populations exposed to atmospheric radionuclide releases. The individual codes may be used alone for various assessment applications or may be run as a system. This presentation provides an overview and introduction to this system of computer codes and their use in conducting nuclear assessments. Radionuclides are handled by CRRIS either in terms of the released radionuclides or in terms of exposure radionuclides which consist of both the released nuclides and all (or a subset of) the decay daughters that grow in during environmental transport. The capability of CRRIS to handle radionuclide chains is accomplished through PRIMUS which serves as a preprocessor by accessing a library of radionuclide decay data and sets up matricies of decay constants which are used by the other CRRIS codes in all calculations involving transport and decay. PRIMUS may also be run independently by the user to define the decay chains, radionuclide decay constants, and branching ratios.

  9. Quantitative Analysis of Major Factors Affecting Black Carbon Transport and Concentrations in the Unique Atmospheric Structures of Urban Environment

    NASA Astrophysics Data System (ADS)

    Liang, Marissa Shuang

    Black carbon (BC) from vehicular emission in transportation is a principal component of particulate matters ≤ 2.5 mum (PM2.5). PM2.5 and other diesel emission pollutants (e.g., NOx) are regulated by the Clean Air Act (CAA) according to the National Ambient Air Quality standards (NAAQS). This doctoral dissertation details a study on transport behaviors of black carbon and PM2.5 from transportation routes, their relations with the atmospheric structure of an urban formation, and their relations with the use of biodiesel fuels. The results have implications to near-road risk assessment and to the development of sustainable transportation solutions in urban centers. The first part of study quantified near-roadside black carbon transport as a function of particulate matter (PM) size and composition, as well as microclimatic variables (temperature and wind fields) at the interstate highway I-75 in northern Cincinnati, Ohio. Among variables examined, wind speed and direction significantly affect the roadside transport of black carbon and hence its effective emission factor. Observed non-Gaussian dispersion occurred during low wind and for wind directions at acute angles or upwind to the receptors, mostly occurring in the morning hours. Meandering of air pollutant mass under thermal inversion is likely the driving force. In contrary, Gaussian distribution predominated in daytime of strong downwinds. The roles of urban atmospheric structure, wind fields, and the urban heat island (UHI) effects were further examined on pollutant dispersion and transport. Spatiotemporal variations of traffic flow, atmospheric structure, ambient temperature and PM2.5 concentration data from 14 EPA-certified NAAQS monitoring stations, were analyzed in relation to land-use in the Cincinnati metropolitan area. The results show a decade-long UHI effects with higher interior temperature than that in exurban, and a prominent nocturnal thermal inversion frequent in urban boundary layer. The

  10. MICROBIAL TRANSFORMATIONS OF RADIONUCLIDES AND ENVIRONMENTAL RESTORATION THROUGH BIOREMEDIATION.

    SciTech Connect

    FRANCIS, A.J.

    2006-09-29

    Treatment of waste streams containing radionuclides, the remediation of contaminated materials, soils, and water, and the safe and economical disposal of radionuclides and toxic metals containing wastes is a major concern. Radionuclides may exist in various oxidation states and may be present as oxide, coprecipitates, inorganic, and organic complexes depending on the process and waste stream. Unlike organic contaminants, the metals cannot be destroyed, but must either be converted to a stable form or removed. Microorganisms present in the natural environment play a major role in the mobilization and immobilization of radionuclides and toxic metals by direct enzymatic or indirect non-enzymatic actions and could affect the chemical nature of the radionuclides by altering the speciation, solubility and sorption properties and thus could increase or decrease the concentrations of radionuclides in solution. Fundamental understanding of the mechanisms of microbiological transformations of various chemical forms of uranium present in wastes and contaminated soils and water has led to the development of novel bioremediation processes. One process uses anaerobic bacteria to stabilize the radionuclides by reductive precipitation from higher to lower oxidation state with a concurrent reduction in volume due to the dissolution and removal of nontoxic elements from the waste matrix. In an another process, uranium and other toxic metals are removed from contaminated surfaces, soils, and wastes by extracting with the chelating agent citric acid. Uranium is recovered from the citric acid extract after biodegradation followed by photodegradation in a concentrated form as UO{sub 3} {center_dot} 2H{sub 2}O for recycling or appropriate disposal. These processes use all naturally occurring materials, common soil bacteria, naturally occurring organic compound citric acid and sunlight.

  11. Radionuclide injury to the lung.

    PubMed Central

    Dagle, G E; Sanders, C L

    1984-01-01

    Radionuclide injury to the lung has been studied in rats, hamsters, dogs, mice and baboons. Exposure of the lung to high dose levels of radionuclides produces a spectrum of progressively more severe functional and morphological changes, ranging from radiation pneumonitis and fibrosis to lung tumors. These changes are somewhat similar for different species. Their severity can be related to the absorbed radiation dose (measured in rads) produced by alpha, beta or gamma radiation emanating from various deposited radionuclides. The chemicophysical forms of radionuclides and spatial-temporal factors are also important variables. As with other forms of injury to the lung, repair attempts are highlighted by fibrosis and proliferation of pulmonary epithelium. Lung tumors are the principal late effect observed in experimental animals following pulmonary deposition of radionuclides at dose levels that do not result in early deaths from radiation pneumonitis or fibrosis. The predominant lung tumors described have been of epithelial origin and have been classified, in decreasing frequency of occurrence, as adenocarcinoma, bronchioloalveolar carcinoma, epidermoid carcinomas and combined epidermoid and adenocarcinoma. Mesothelioma and fibrosarcoma have been observed in rats, but less commonly in other species. Hemangiosarcomas were frequency observed in dogs exposed to beta-gamma emitters, and occasionally in rats exposed to alpha emitters. These morphologic changes in the lungs of experimental animals were reviewed and issues relevant to the prediction of human hazards discussed. PMID:6376095

  12. Radionuclide detection devices and associated methods

    DOEpatents

    Mann, Nicholas R.; Lister, Tedd E.; Tranter, Troy J.

    2011-03-08

    Radionuclide detection devices comprise a fluid cell comprising a flow channel for a fluid stream. A radionuclide collector is positioned within the flow channel and configured to concentrate one or more radionuclides from the fluid stream onto at least a portion of the radionuclide collector. A scintillator for generating scintillation pulses responsive to an occurrence of a decay event is positioned proximate at least a portion of the radionuclide collector and adjacent to a detection system for detecting the scintillation pulses. Methods of selectively detecting a radionuclide are also provided.

  13. H2O2-Induced Oxidative Stress Affects SO4= Transport in Human Erythrocytes

    PubMed Central

    Morabito, Rossana; Romano, Orazio; La Spada, Giuseppa; Marino, Angela

    2016-01-01

    The aim of the present investigation was to verify the effect of H2O2-induced oxidative stress on SO4= uptake through Band 3 protein, responsible for Cl-/HCO3- as well as for cell membrane deformability, due to its cross link with cytoskeletal proteins. The role of cytoplasmic proteins binding to Band 3 protein has been also considered by assaying H2O2 effects on hemoglobin-free resealed ghosts of erythrocytes. Oxidative conditions were induced by 30 min exposure of human erythrocytes to different H2O2 concentrations (10 to 300 μM), with or without GSH (glutathione, 2 mM) or curcumin (10 μM), compounds with proved antioxidant properties. Since SO4= influx through Band 3 protein is slower and better controllable than Cl- or HCO3- exchange, the rate constant for SO4= uptake was measured to prove anion transport efficiency, while MDA (malondialdehyde) levels and –SH groups were estimated to quantify the effect of oxidative stress. H2O2 induced a significant decrease in rate constant for SO4= uptake at both 100 and 300 μM H2O2. This reduction, observed in erythrocytes but not in resealed ghosts and associated to increase in neither MDA levels nor in –SH groups, was impaired by both curcumin and GSH, whereas only curcumin effectively restored H2O2-induced changes in erythrocytes shape. Our results show that: i) 30 min exposure to 300 μM H2O2 reduced SO4= uptake in human erythrocytes; ii) oxidative damage was revealed by the reduction in rate constant for SO4= uptake, but not by MDA or –SH groups levels; iii) the damage was produced via cytoplasmic components which cross link with Band 3 protein; iv) the natural antioxidant curcumin may be useful in protecting erythrocytes from oxidative injury; v) SO4= uptake through Band 3 protein may be reasonably suggested as a tool to monitor erythrocytes function under oxidative conditions possibly deriving from alcohol consumption, use of drugs, radiographic contrast media administration, hyperglicemia or

  14. H2O2-Induced Oxidative Stress Affects SO4= Transport in Human Erythrocytes.

    PubMed

    Morabito, Rossana; Romano, Orazio; La Spada, Giuseppa; Marino, Angela

    2016-01-01

    The aim of the present investigation was to verify the effect of H2O2-induced oxidative stress on SO4= uptake through Band 3 protein, responsible for Cl-/HCO3- as well as for cell membrane deformability, due to its cross link with cytoskeletal proteins. The role of cytoplasmic proteins binding to Band 3 protein has been also considered by assaying H2O2 effects on hemoglobin-free resealed ghosts of erythrocytes. Oxidative conditions were induced by 30 min exposure of human erythrocytes to different H2O2 concentrations (10 to 300 μM), with or without GSH (glutathione, 2 mM) or curcumin (10 μM), compounds with proved antioxidant properties. Since SO4= influx through Band 3 protein is slower and better controllable than Cl- or HCO3- exchange, the rate constant for SO4= uptake was measured to prove anion transport efficiency, while MDA (malondialdehyde) levels and -SH groups were estimated to quantify the effect of oxidative stress. H2O2 induced a significant decrease in rate constant for SO4= uptake at both 100 and 300 μM H2O2. This reduction, observed in erythrocytes but not in resealed ghosts and associated to increase in neither MDA levels nor in -SH groups, was impaired by both curcumin and GSH, whereas only curcumin effectively restored H2O2-induced changes in erythrocytes shape. Our results show that: i) 30 min exposure to 300 μM H2O2 reduced SO4= uptake in human erythrocytes; ii) oxidative damage was revealed by the reduction in rate constant for SO4= uptake, but not by MDA or -SH groups levels; iii) the damage was produced via cytoplasmic components which cross link with Band 3 protein; iv) the natural antioxidant curcumin may be useful in protecting erythrocytes from oxidative injury; v) SO4= uptake through Band 3 protein may be reasonably suggested as a tool to monitor erythrocytes function under oxidative conditions possibly deriving from alcohol consumption, use of drugs, radiographic contrast media administration, hyperglicemia or neurodegenerative

  15. Fusarium Oxysporum Volatiles Enhance Plant Growth Via Affecting Auxin Transport and Signaling.

    PubMed

    Bitas, Vasileios; McCartney, Nathaniel; Li, Ningxiao; Demers, Jill; Kim, Jung-Eun; Kim, Hye-Seon; Brown, Kathleen M; Kang, Seogchan

    2015-01-01

    Volatile organic compounds (VOCs) have well-documented roles in plant-plant communication and directing animal behavior. In this study, we examine the less understood roles of VOCs in plant-fungal relationships. Phylogenetically and ecologically diverse strains of Fusarium oxysporum, a fungal species complex that often resides in the rhizosphere of assorted plants, produce volatile compounds that augment shoot and root growth of Arabidopsis thaliana and tobacco. Growth responses of A. thaliana hormone signaling mutants and expression patterns of a GUS reporter gene under the auxin-responsive DR5 promoter supported the involvement of auxin signaling in F. oxysporum volatile-mediated growth enhancement. In addition, 1-naphthylthalamic acid, an inhibitor of auxin efflux, negated F. oxysporum volatile-mediated growth enhancement in both plants. Comparison of the profiles of volatile compounds produced by F. oxysporum strains that differentially affected plant growth suggests that the relative compositions of both growth inhibitory and stimulatory compounds may determine the degree of plant growth enhancement. Volatile-mediated signaling between fungi and plants may represent a potentially conserved, yet mostly overlooked, mechanism underpinning plant-fungus interactions and fungal niche adaption.

  16. Fusarium Oxysporum Volatiles Enhance Plant Growth Via Affecting Auxin Transport and Signaling

    PubMed Central

    Bitas, Vasileios; McCartney, Nathaniel; Li, Ningxiao; Demers, Jill; Kim, Jung-Eun; Kim, Hye-Seon; Brown, Kathleen M.; Kang, Seogchan

    2015-01-01

    Volatile organic compounds (VOCs) have well-documented roles in plant-plant communication and directing animal behavior. In this study, we examine the less understood roles of VOCs in plant-fungal relationships. Phylogenetically and ecologically diverse strains of Fusarium oxysporum, a fungal species complex that often resides in the rhizosphere of assorted plants, produce volatile compounds that augment shoot and root growth of Arabidopsis thaliana and tobacco. Growth responses of A. thaliana hormone signaling mutants and expression patterns of a GUS reporter gene under the auxin-responsive DR5 promoter supported the involvement of auxin signaling in F. oxysporum volatile-mediated growth enhancement. In addition, 1-naphthylthalamic acid, an inhibitor of auxin efflux, negated F. oxysporum volatile-mediated growth enhancement in both plants. Comparison of the profiles of volatile compounds produced by F. oxysporum strains that differentially affected plant growth suggests that the relative compositions of both growth inhibitory and stimulatory compounds may determine the degree of plant growth enhancement. Volatile-mediated signaling between fungi and plants may represent a potentially conserved, yet mostly overlooked, mechanism underpinning plant-fungus interactions and fungal niche adaption. PMID:26617587

  17. Radionuclides in Chesapeake Bay sediments

    NASA Technical Reports Server (NTRS)

    Cressy, P. J., Jr.

    1976-01-01

    Natural and manmade gamma-ray emitting radionuclides were measured in Chesapeake Bay sediments taken near the Calvert Cliffs Nuclear Power Plant site. Samples represented several water depths, at six locations, for five dates encompassing a complete seasonal cycle. Radionuclide contents of dry sediments ranged as follows: Tl-208, 40 to 400 pCi/kg; Bi-214, 200 to 800 pCi/kg; K, 0.04 to 2.1 percent; Cs-137 5 to 1900 pCi/kg; Ru106, 40 to 1000 pCikg Co60, 1 to 27 pCi/kg. In general, radionuclide contents were positively correlated with each other and negatively correlated with sediment grain size.

  18. 100 years of radionuclide metrology.

    PubMed

    Judge, S M; Arnold, D; Chauvenet, B; Collé, R; De Felice, P; García-Toraño, E; Wätjen, U

    2014-05-01

    The discipline of radionuclide metrology at national standards institutes started in 1913 with the certification by Curie, Rutherford and Meyer of the first primary standards of radium. In early years, radium was a valuable commodity and the aim of the standards was largely to facilitate trade. The focus later changed to providing standards for the new wide range of radionuclides, so that radioactivity could be used for healthcare and industrial applications while minimising the risk to patients, workers and the environment. National measurement institutes responded to the changing demands by developing new techniques for realising primary standards of radioactivity. Looking ahead, there are likely to be demands for standards for new radionuclides used in nuclear medicine, an expansion of the scope of the field into quantitative imaging to facilitate accurate patient dosimetry for nuclear medicine, and an increasing need for accurate standards for radioactive waste management and nuclear forensics.

  19. Report to the American Physical Society of the Study Group on Radionuclide Release From Severe Accidents at Nuclear Power Plants

    NASA Astrophysics Data System (ADS)

    Shaw, George

    The release of radioiodine during the Three Mile Island (TMI) accident was more than an order of magnitude smaller than what had been predicted from analyses of hypothetical nuclear accidents. The Reactor Safety Study of 1975 (RSS), which carried out the analyses, is a fundamental factor in formulating regulations concerned with such accidents. This American Physical Society (APS) study group report is a result of the obvious need to reevaluate the RSS analysis of the “source term,” that is, the amount of various radionuclides that are predicted to be emitted under various reactor failure scenarios.The report includes an introductory background to the history of nuclear reactor accidents and accident studies and to the health aspects of radionuclide releases. It then describes nuclear reactors and reactor failure modes, including reasonably detailed descriptions of particular modes thought to be especially critical. The most extensive discussion concerns the chemical and physical processes important in the generation, transport, and release of radionuclides. The large computer codes used to model these processes are considered and evaluated. The results of some of the computer runs are examined in the light of a simplified but informative model to evaluate those features of an accident that are most likely to affect the source term. A review of the research programs currently underway precedes both the study group conclusions about the need to revise the source terms from those in the RSS and recommendations for further studies that are necessary to better evaluate the source term.

  20. Bioremediation: a genuine technology to remediate radionuclides from the environment.

    PubMed

    Prakash, Dhan; Gabani, Prashant; Chandel, Anuj K; Ronen, Zeev; Singh, Om V

    2013-07-01

    Radionuclides in the environment are a major human and environmental health concern. Like the Chernobyl disaster of 1986, the Fukushima Daiichi nuclear disaster in 2011 is once again causing damage to the environment: a large quantity of radioactive waste is being generated and dumped into the environment, and if the general population is exposed to it, may cause serious life-threatening disorders. Bioremediation has been viewed as the ecologically responsible alternative to environmentally destructive physical remediation. Microorganisms carry endogenous genetic, biochemical and physiological properties that make them ideal agents for pollutant remediation in soil and groundwater. Attempts have been made to develop native or genetically engineered (GE) microbes for the remediation of environmental contaminants including radionuclides. Microorganism-mediated bioremediation can affect the solubility, bioavailability and mobility of radionuclides. Therefore, we aim to unveil the microbial-mediated mechanisms for biotransformation of radionuclides under various environmental conditions as developing strategies for waste management of radionuclides. A discussion follows of '-omics'-integrated genomics and proteomics technologies, which can be used to trace the genes and proteins of interest in a given microorganism towards a cell-free bioremediation strategy.

  1. Bioremediation: a genuine technology to remediate radionuclides from the environment

    PubMed Central

    Prakash, Dhan; Gabani, Prashant; Chandel, Anuj K; Ronen, Zeev; Singh, Om V

    2013-01-01

    Summary Radionuclides in the environment are a major human and environmental health concern. Like the Chernobyl disaster of 1986, the Fukushima Daiichi nuclear disaster in 2011 is once again causing damage to the environment: a large quantity of radioactive waste is being generated and dumped into the environment, and if the general population is exposed to it, may cause serious life-threatening disorders. Bioremediation has been viewed as the ecologically responsible alternative to environmentally destructive physical remediation. Microorganisms carry endogenous genetic, biochemical and physiological properties that make them ideal agents for pollutant remediation in soil and groundwater. Attempts have been made to develop native or genetically engineered (GE) microbes for the remediation of environmental contaminants including radionuclides. Microorganism-mediated bioremediation can affect the solubility, bioavailability and mobility of radionuclides. Therefore, we aim to unveil the microbial-mediated mechanisms for biotransformation of radionuclides under various environmental conditions as developing strategies for waste management of radionuclides. A discussion follows of ‘-omics’-integrated genomics and proteomics technologies, which can be used to trace the genes and proteins of interest in a given microorganism towards a cell-free bioremediation strategy. PMID:23617701

  2. Radionuclide Imaging of Cardiovascular Infection.

    PubMed

    Ahmed, Fozia Zahir; James, Jackie; Memmott, Matthew J; Arumugam, Parthiban

    2016-02-01

    Owing to expanding clinical indications, cardiac implantable electronic devices (CIEDs) are being increasingly used. Despite improved surgical techniques and the use of prophylactic antimicrobial therapy, the rate of CIED-related infection is also increasing. Infection is a potentially serious complication, with clinical manifestations ranging from surgical site infection and local symptoms in the region of the generator pocket to fulminant endocarditis. The utility of radionuclide imaging as a stand-alone noninvasive diagnostic imaging test in patients with suspected endocarditis has been less frequently examined. This article summarizes the recent advances in radionuclide imaging for evaluation of patients with suspected cardiovascular infections.

  3. AN INQUIRY INTO THE STRUCTURAL CONDITIONS AFFECTING FLUID TRANSPORT IN THE INTERSTITIAL TISSUE OF THE SKIN

    PubMed Central

    McMaster, Philip D.

    1941-01-01

    With the aim of determining the structural conditions which affect fluid movement in the cutaneous connective tissue of mice, various test fluids were brought into contact with it under conditions such that neither blood vessels nor lymphatics were directly entered. Locke's solution, mouse serum, and a mixture of Locke's solution with a dye which causes edema were all employed. At atmospheric pressure, Locke's solution entered the tissues intermittently. When subjected to very low pressures it continued to enter the skin intermittently and at approximately the same rate. At pressures above 4.5 cm. of water, however, the flow became continuous but it did not increase in rate significantly until pressures of about 8.5 cm. were employed. There was no relationship between the rate of flow and the pressure employed. At a pressure of about 8.5 cm. the resistance of the tissues seemed to give way abruptly as if the formed elements had been separated. This has been termed the "breaking point." After it had been reached each further increase of pressure produced a proportionately greater inflow. Under the conditions of our experiments, the dye-Locke"s solution and also the homologous serum failed to enter the tissues at atmospheric pressure. It was necessary to subject these fluids to pressure to force them into the skin at the same rate at which the Locke's solution entered it spontaneously. Under these circumstances the dye-Locke's solution and the serum entered the skin continuously, not intermittently like the plain Locke's solution. As the pressure was gradually raised, no significant increase of flow into the tissues occurred until a point was reached, on the average 8.5 cm. of water, at which fluid suddenly began to enter very rapidly. This point, the "breaking point" already mentioned, was reached at the same pressure irrespective of the character of the fluid employed, showing that the phenomenon was produced by the fluid bulk. Once it had been attained, further

  4. A study of the physical-chemical mechanisms and variables which affect the transport of inorganic and organic heterogeneous systems

    SciTech Connect

    Anderson, M.A.; Zeltner, W.A.

    1990-07-01

    In order to model transport of dissolved ions in subsurface environments, one should understand how these ions interact with solid phase adsorbents. Our primary goal has been investigating the reaction mechanisms which affect microcontaminant partitioning between aqueous solutions and solid phase adsorbents, using goethite ({alpha}-FeOOH) as a model adsorbent. Cylindrical internal reflection -- Fourier transform infrared (CIR-FTIR) spectroscopy has been developed as the primary technique for this study. Wet chemical adsorption studies, acoustophoresis and electrophoretic mobility have been used to obtain supporting information as needed. Phenol and o-nitrophenol did not adsorb to goethite. Benzoate, phthalate and p-hydroxybenzoate all adsorbed via a bidentate mechanism to two adjacent iron atoms, while salicylate and 2,4-dihydroxybenzoate formed a chelate complex to single iron atoms. Phosphate adsorption was predominately bidentate.

  5. Radionuclide labeled lymphocytes for therapeutic use

    DOEpatents

    Srivastava, Suresh C.; Fawwaz, Rashid A.; Richards, Powell

    1985-01-01

    Lymphocytes labelled with .beta.-emitting radionuclides are therapeutically useful, particularly for lymphoid ablation. They are prepared by incubation of the lymphocytes with the selected radionuclide-oxine complex.

  6. Radionuclide labeled lymphocytes for therapeutic use

    DOEpatents

    Srivastava, S.C.; Fawwaz, R.A.; Richards, P.

    1983-05-03

    Lymphocytes labelled with ..beta..-emitting radionuclides are therapeutically useful, particularly for lymphoid ablation. They are prepared by incubation of the lymphocytes with the selected radionuclide-oxine complex.

  7. Assessing factors affecting the thermal properties of a passive thermal refuge using three-dimensional hydrodynamic flow and transport modeling

    USGS Publications Warehouse

    Decker, Jeremy D.; Swain, Eric D.; Stith, Bradley M.; Langtimm, Catherine A.

    2013-01-01

    Everglades restoration activities may cause changes to temperature and salinity stratification at the Port of the Islands (POI) marina, which could affect its suitability as a cold weather refuge for manatees. To better understand how the Picayune Strand Restoration Project (PSRP) may alter this important resource in Collier County in southwestern Florida, the USGS has developed a three-dimensional hydrodynamic model for the marina and canal system at POI. Empirical data suggest that manatees aggregate at the site during winter because of thermal inversions that provide warmer water near the bottom that appears to only occur in the presence of salinity stratification. To study these phenomena, the environmental fluid dynamics code simulator was used to represent temperature and salinity transport within POI. Boundary inputs were generated using a larger two-dimensional model constructed with the flow and transport in a linked overland-aquifer density-dependent system simulator. Model results for a representative winter period match observed trends in salinity and temperature fluctuations and produce temperature inversions similar to observed values. Modified boundary conditions, representing proposed PSRP alterations, were also tested to examine the possible effect on the salinity stratification and temperature inversion within POI. Results show that during some periods, salinity stratification is reduced resulting in a subsequent reduction in temperature inversion compared with the existing conditions simulation. This may have an effect on POI’s suitability as a passive thermal refuge for manatees and other temperature-sensitive species. Additional testing was completed to determine the important physical relationships affecting POI’s suitability as a refuge.

  8. Fate and transport of oil sand process-affected water into the underlying clay till: a field study.

    PubMed

    Abolfazlzadehdoshanbehbazari, Mostafa; Birks, S Jean; Moncur, Michael C; Ulrich, Ania C

    2013-08-01

    The South Tailings Pond (STP) is a ~2300-ha tailing pond operated by Suncor Energy Inc. that has received oil sand process-affected (PA) water and mature fine tailings since 2006. The STP is underlain by a clay till, which is in turn underlain by the Wood Creek Sand Channel (WCSC). The sandy deposits of the WCSC provide greater geotechnical stability but could act as a potential flow pathway for PA water to migrate off site and into the Athabasca River. Preliminary modeling of the STP suggests that PA water from the pond will infiltrate into the underlying sand channel, but the extent and development of this impact is still poorly understood. Suncor Energy Inc. built interception wells and a cut-off-wall to control any potential seepage. Here we present the results of an investigation of the fate and transport of PA water in clay till underlying a 10 m × 10 m infiltration pond that was constructed on the southeastern portion of the STP. The geochemistry of pore water in the till underlying the infiltration pond was determined prior to filling with process-affected water (2008) and two years after the infiltration pond was filled with PA waters (2010). Pore water was analyzed for metals, cations, anions, and isotopes ((2)H and (18)O). The distribution of conservative tracers ((18)O and chloride) indicated migration of the PA waters to approximately 0.9 m, but the migrations of major ions and metals were significantly delayed relative to this depth. Uptake of Na and Mo and release of Ca, Mg, Mn, Ba, and Sr suggest that adsorption and ion exchange reactions are the foremost attenuation processes controlling inorganic solutes transport.

  9. Genotype and allele frequencies of drug-metabolizing enzymes and drug transporter genes affecting immunosuppressants in the Spanish white population.

    PubMed

    Bosó, Virginia; Herrero, María J; Buso, Enrique; Galán, Juan; Almenar, Luis; Sánchez-Lázaro, Ignacio; Sánchez-Plumed, Jaime; Bea, Sergio; Prieto, Martín; García, María; Pastor, Amparo; Sole, Amparo; Poveda, José Luis; Aliño, Salvador F

    2014-04-01

    Interpatient variability in drug response can be widely explained by genetically determined differences in metabolizing enzymes, drug transporters, and drug targets, leading to different pharmacokinetic and/or pharmacodynamic behaviors of drugs. Genetic variations affect or do not affect drug responses depending on their influence on protein activity and the relevance of such proteins in the pathway of the drug. Also, the frequency of such genetic variations differs among populations, so the clinical relevance of a specific variation is not the same in all of them. In this study, a panel of 33 single nucleotide polymorphisms in 14 different genes (ABCB1, ABCC2, ABCG2, CYP2B6, CYP2C19, CYP2C9, CYP3A4, CYP3A5, MTHFR, NOD2/CARD15, SLCO1A2, SLCO1B1, TPMT, and UGT1A9), encoding for the most relevant metabolizing enzymes and drug transporters relating to immunosuppressant agents, was analyzed to determine the genotype profile and allele frequencies in comparison with HapMap data. A total of 570 Spanish white recipients and donors of solid organ transplants were included. In 24 single nucleotide polymorphisms, statistically significant differences in allele frequency were observed. The largest differences (>100%) occurred in ABCB1 rs2229109, ABCG2 rs2231137, CYP3A5 rs776746, NOD2/CARD15 rs2066844, TPMT rs1800462, and UGT1A9 rs72551330. In conclusion, differences were recorded between the Spanish and other white populations in terms of allele frequency and genotypic distribution. Such differences may have implications in relation to dose requirements and drug-induced toxicity. These data are important for further research to help explain interindividual pharmacokinetic and pharmacodynamic variability in response to drug therapy.

  10. Fate and transport of oil sand process-affected water into the underlying clay till: A field study

    NASA Astrophysics Data System (ADS)

    Abolfazlzadehdoshanbehbazari, Mostafa; Birks, S. Jean; Moncur, Michael C.; Ulrich, Ania C.

    2013-08-01

    The South Tailings Pond (STP) is a ~ 2300-ha tailing pond operated by Suncor Energy Inc. that has received oil sand process-affected (PA) water and mature fine tailings since 2006. The STP is underlain by a clay till, which is in turn underlain by the Wood Creek Sand Channel (WCSC). The sandy deposits of the WCSC provide greater geotechnical stability but could act as a potential flow pathway for PA water to migrate off site and into the Athabasca River. Preliminary modeling of the STP suggests that PA water from the pond will infiltrate into the underlying sand channel, but the extent and development of this impact is still poorly understood. Suncor Energy Inc. built interception wells and a cut-off-wall to control any potential seepage. Here we present the results of an investigation of the fate and transport of PA water in clay till underlying a 10 m × 10 m infiltration pond that was constructed on the southeastern portion of the STP. The geochemistry of pore water in the till underlying the infiltration pond was determined prior to filling with process-affected water (2008) and two years after the infiltration pond was filled with PA waters (2010). Pore water was analyzed for metals, cations, anions, and isotopes (2H and 18O). The distribution of conservative tracers (18O and chloride) indicated migration of the PA waters to approximately 0.9 m, but the migrations of major ions and metals were significantly delayed relative to this depth. Uptake of Na and Mo and release of Ca, Mg, Mn, Ba, and Sr suggest that adsorption and ion exchange reactions are the foremost attenuation processes controlling inorganic solutes transport.

  11. Hypertension-associated point mutations in the adducin alpha and beta subunits affect actin cytoskeleton and ion transport.

    PubMed Central

    Tripodi, G; Valtorta, F; Torielli, L; Chieregatti, E; Salardi, S; Trusolino, L; Menegon, A; Ferrari, P; Marchisio, P C; Bianchi, G

    1996-01-01

    The adducin heterodimer is a protein affecting the assembly of the actin-based cytoskeleton. Point mutations in rat adducin alpha (F316Y) and beta (Q529R) subunits are involved in a form of rat primary hypertension (MHS) associated with faster kidney tubular ion transport. A role for adducin in human primary hypertension has also been suggested. By studying the interaction of actin with purified normal and mutated adducin in a cell-free system and the actin assembly in rat kidney epithelial cells (NRK-52E) transfected with mutated rat adducin cDNA, we show that the adducin isoforms differentially modulate: (a) actin assembly both in a cell-free system and within transfected cells; (b) topography of alpha V integrin together with focal contact proteins; and (c) Na-K pump activity at V(max) (faster with the mutated isoforms, 1281 +/- 90 vs 841 +/- 30 nmol K/h.mg pt., P < 0.0001). This co-modulation suggests a role for adducin in the constitutive capacity of the epithelia both to transport ions and to expose adhesion molecules. These findings may also lead to the understanding of the relation between adducin polymorphism and blood pressure and to the development of new approaches to the study of hypertension-associated organ damage. PMID:8675693

  12. Implications for Ecosystem Services of Watershed Processes that affect the Transport and Transformations of Mercury in an Adirondack Stream Basin

    NASA Astrophysics Data System (ADS)

    Burns, D. A.; Riva-Murray, K.; Bradley, P. M.

    2012-12-01

    Mercury (Hg) is a potent neurotoxin that can affect the health of humans and wildlife through the ingestion of methyl Hg. Mercury contamination of ecosystems originates from human activities such as mining, coal burning and other industrial emissions, and the use of Hg-containing products. Natural sources such as volcanic and geothermal emissions and the weathering of Hg-bearing minerals also contribute to Hg contamination, but are believed to be minor sources in most ecosystems. Various ecosystem disturbances including fires, forest harvesting, and the submergence of land by impoundment may also contribute to Hg ecosystem contamination by mobilizing stores that have previously originated from the sources described above. Mercury from a mix of regional and global emissions sources is transported in the atmosphere to remote landscapes that are distant from local emissions sources. The Adirondacks of New York State is a forested, mountainous region characterized by abundant lakes and streams, and is distant from local emissions sources. Recreational fishing, wildlife viewing, hiking, and hunting are valued ecosystem services in this region. Here, we report on the relevance to ecosystem services of findings based on five years of Hg data collection of stream water, groundwater, invertebrates, and fish in the upper Hudson River basin in the central part of the Adirondack region. The New York State Dept. of Health has issued fish consumption advisories for the entire Adirondacks based on elevated levels previously measured in lakes and rivers of this region. Our work seeks improved understanding and models of the landscape sources and watershed processes that control the transformation of Hg to its methyl form (MeHg), the transport of MeHg to streams, and bioaccumulation of MeHg in aquatic food webs. Mean annual atmospheric Hg deposition was 6.3 μg/m2/yr during 2007-09, compared to mean annual filtered total Hg stream yields of 1.66 μg/m2/yr and filtered MeHg stream

  13. Radionuclide Sensors for Subsurface Water Monitoring

    SciTech Connect

    Timothy DeVol

    2006-06-30

    Contamination of the subsurface by radionuclides is a persistent and vexing problem for the Department of Energy. These radionuclides must be measured in field studies and monitoed in the long term when they cannot be removed. However, no radionuclide sensors existed for groundwater monitoring prior to this team's research under the EMSP program Detection of a and b decays from radionuclides in water is difficult due to their short ranges in condensed media.

  14. Multi-scale interactions affecting transport, storage, and processing of solutes and sediments in stream corridors (Invited)

    NASA Astrophysics Data System (ADS)

    Harvey, J. W.; Packman, A. I.

    2010-12-01

    Surface water and groundwater flow interact with the channel geomorphology and sediments in ways that determine how material is transported, stored, and transformed in stream corridors. Solute and sediment transport affect important ecological processes such as carbon and nutrient dynamics and stream metabolism, processes that are fundamental to stream health and function. Many individual mechanisms of transport and storage of solute and sediment have been studied, including surface water exchange between the main channel and side pools, hyporheic flow through shallow and deep subsurface flow paths, and sediment transport during both baseflow and floods. A significant challenge arises from non-linear and scale-dependent transport resulting from natural, fractal fluvial topography and associated broad, multi-scale hydrologic interactions. Connections between processes and linkages across scales are not well understood, imposing significant limitations on system predictability. The whole-stream tracer experimental approach is popular because of the spatial averaging of heterogeneous processes; however the tracer results, implemented alone and analyzed using typical models, cannot usually predict transport beyond the very specific conditions of the experiment. Furthermore, the results of whole stream tracer experiments tend to be biased due to unavoidable limitations associated with sampling frequency, measurement sensitivity, and experiment duration. We recommend that whole-stream tracer additions be augmented with hydraulic and topographic measurements and also with additional tracer measurements made directly in storage zones. We present examples of measurements that encompass interactions across spatial and temporal scales and models that are transferable to a wide range of flow and geomorphic conditions. These results show how the competitive effects between the different forces driving hyporheic flow, operating at different spatial scales, creates a situation

  15. Measurement of radionuclides in waste packages

    DOEpatents

    Brodzinski, Ronald L.; Perkins, Richard W.; Rieck, Henry G.; Wogman, Ned A.

    1986-01-01

    A method is described for non-destructively assaying the radionuclide content of solid waste in a sealed container by analysis of the waste's gamma-ray spectrum and neutron emissions. Some radionuclides are measured by characteristic photopeaks in the gamma-ray spectrum; transuranic nuclides are measured by neutron emission rate; other radionuclides are measured by correlation with those already measured.

  16. [Role of Radionuclide Technologies in Medicine].

    PubMed

    Chernyaev, A P; Belousov, A V; Varzar, S M; Borchegovskaya, P Y; Nikolaeva, A A; Krusanov, G A

    2016-01-01

    The paper describes the role of radionuclide technologies among the nuclear-physical methods used in medicine. The condition and prospects of the development of nuclear technology with use of radionuclides in medicine, and in particular, the method of brachytherapy are analyzed. The analysis of the current state of applying radionuclide facilities in medicine is provided.

  17. TECHNOLOGIES FOR RADON AND RADIONUCLIDE REMOVAL

    EPA Science Inventory

    This paper provides a summary of the technologies that are currently being used to remove radionuclides from drinking water. The radionuclides that are featured are the radionuclides currently regulated by EPA; radium, radon and uranium. Tehnologies effective for removal of eac...

  18. Measurement of radionuclides in waste packages

    DOEpatents

    Brodzinski, R.L.; Perkins, R.W.; Rieck, H.G.; Wogman, N.A.

    1984-09-12

    A method is described for non-destructively assaying the radionuclide content of solid waste in a sealed container by analysis of the waste's gamma-ray spectrum and neutron emissions. Some radionuclides are measured by characteristic photopeaks in the gamma-ray spectrum; transuranic nuclides are measured by neutron emission rate; other radionuclides are measured by correlation with those already measured.

  19. Biogeochemical indication of pollution with metals and radionuclides in oil-producing regions

    NASA Astrophysics Data System (ADS)

    Moiseenko, T. I.; Gashev, S. N.

    2012-12-01

    The results of investigation of the biogeochemical indication of pollution with metals and radio-nuclides in the oil-producing regions of Western Siberia are presented. It was ascertained that eight years after the oil spill, biota components (lichens, mosses, small mammals, etc.) on technogenic territories contain higher elemental concentrations as compared to the background sites, which allows us to use them to assess the anthropogenic load. Original data pertaining to radionuclide content in mosses and woody plants in Western Siberia are presented; they prove the fact that both oil production and trans-regional transportation contribute to the total pollution of Western Siberia with radionuclides.

  20. Prospects for the methods of radionuclide production

    SciTech Connect

    Karamian, S. A. Dmitriev, S. N.

    2015-03-30

    In the present report, methods of radionuclide production for the nuclear-medicine purposes are described. In a budget approach, the application of low-energy accelerators is especially advantageous. Intense flux of bremsstrahlung at electron accelerators or high-current cyclotron beams of alpha particles must supply a great yield for many isotopes. The choice of a target material and of the projectile energy provides enough variation for concrete species formation. The innovating procedures are here proposed for optimizing of methods, for instance, application of the noble-gas target for production and transport of activities. The known and new variants of the “generator” scheme are discussed. Many isotopes are listed as promising in the context of the therapeutic and theragnostic applications. Among them are isotopes/isomers emitting soft radiation for the selective and careful body treatment, also the positron emitters for PET, and the halogen and alkali-metal species convenient for chemical separation.

  1. Prospects for the methods of radionuclide production

    NASA Astrophysics Data System (ADS)

    Karamian, S. A.; Dmitriev, S. N.

    2015-03-01

    In the present report, methods of radionuclide production for the nuclear-medicine purposes are described. In a budget approach, the application of low-energy accelerators is especially advantageous. Intense flux of bremsstrahlung at electron accelerators or high-current cyclotron beams of alpha particles must supply a great yield for many isotopes. The choice of a target material and of the projectile energy provides enough variation for concrete species formation. The innovating procedures are here proposed for optimizing of methods, for instance, application of the noble-gas target for production and transport of activities. The known and new variants of the "generator" scheme are discussed. Many isotopes are listed as promising in the context of the therapeutic and theragnostic applications. Among them are isotopes/isomers emitting soft radiation for the selective and careful body treatment, also the positron emitters for PET, and the halogen and alkali-metal species convenient for chemical separation.

  2. Radionuclide evaluation in childhood injuries

    SciTech Connect

    Sty, J.R.; Starshak, R.J.; Hubbard, A.M.

    1983-07-01

    Radionuclide techniques serve an important role in evaluating childhood injuries. Frequently, they can be employed as the initial and definitive examination. At times they represent the only modality that will detect specific injuries such as the skeletal system. Familiarity with the advantages and limitations of tracer techniques will insure appropriate management of childhood injuries.

  3. Natural radionuclide accumulation by raindrops

    NASA Astrophysics Data System (ADS)

    Gusev, Anatoly; Martin, Inacio; Shkevov, Rumen; Alves, Mauro

    2016-07-01

    The laboratory of environmental radiation of ITA (São José dos Campos, 23°11'11″S, 45°52'43″W, 650 MAMSL) performs simultaneous monitoring of a natural radiation background and meteorological parameters. A time resolution of up to 1 minute allows a detailed comparison of changes in meteorological parameters with those of a concentration of ambient radon progenies in the atmosphere. Results of a study of variation of a fallout of radon progenies ^{214}Pb and ^{214}Bi concomitanting rainfalls are present. The radionuclide fallout rate is reconstructed from the observed gamma rate through a simulation of the first kind Volterra integral equation with difference kernel, determined by ratio of precipitating rates of 214Pb and 214Bi and their decay half times. An original straightforward step-by-step procedure was used for the numerical solution of the equation. The radionuclide concentration in the rainwater is calculated as a ratio of the reconstructed fallout to the measured rainfall. It was observed that the radionuclide fallout rate increases as the rainfall one in approximately power 0.6, i.e. the same as the mean raindrop volume. The concentration thereafter decreases as the rainfall rate in power 0.4. A numerical simulation of the process of accumulation of the radionuclides during diffusion and coalescence drop growth and aerosol scavenging during a passage from a cloud to the ground was performed. The results of the simulations agree with the experimental data.

  4. Tumor Immunotargeting Using Innovative Radionuclides

    PubMed Central

    Kraeber-Bodéré, Françoise; Rousseau, Caroline; Bodet-Milin, Caroline; Mathieu, Cédric; Guérard, François; Frampas, Eric; Carlier, Thomas; Chouin, Nicolas; Haddad, Ferid; Chatal, Jean-François; Faivre-Chauvet, Alain; Chérel, Michel; Barbet, Jacques

    2015-01-01

    This paper reviews some aspects and recent developments in the use of antibodies to target radionuclides for tumor imaging and therapy. While radiolabeled antibodies have been considered for many years in this context, only a few have reached the level of routine clinical use. However, alternative radionuclides, with more appropriate physical properties, such as lutetium-177 or copper-67, as well as alpha-emitting radionuclides, including astatine-211, bismuth-213, actinium-225, and others are currently reviving hopes in cancer treatments, both in hematological diseases and solid tumors. At the same time, PET imaging, with short-lived radionuclides, such as gallium-68, fluorine-18 or copper-64, or long half-life ones, particularly iodine-124 and zirconium-89 now offers new perspectives in immuno-specific phenotype tumor imaging. New antibody analogues and pretargeting strategies have also considerably improved the performances of tumor immunotargeting and completely renewed the interest in these approaches for imaging and therapy by providing theranostics, companion diagnostics and news tools to make personalized medicine a reality. PMID:25679452

  5. Differences in the expression of endogenous efflux transporters in MDR1-transfected versus wildtype cell lines affect P-glycoprotein mediated drug transport

    PubMed Central

    Kuteykin-Teplyakov, Konstantin; Luna-Tortós, Carlos; Ambroziak, Kamila; Löscher, Wolfgang

    2010-01-01

    Background and purpose: P-glycoprotein (Pgp) efflux assays are widely used to identify Pgp substrates. The kidney cell lines Madin-Darby canine kidney (MDCK)-II and LLC-PK1, transfected with human MDR1 (ABCB1) are used to provide recombinant models of drug transport. Endogenous transporters in these cells may contribute to the activities of recombinant transporters, so that drug transport in MDR1-transfected cells is often corrected for the transport obtained in parental (wildtype) cells. However, expression of endogenous transporters may vary between transfected and wildtype cells, so that this correction may cause erroneous data. Here, we have measured the expression of endogenous efflux transporters in transfected and wildtype MDCK-II or LLC cells and the consequences for Pgp-mediated drug transport. Experimental approach: Using quantitative real-time RT-PCR, we determined the expression of endogenous Mdr1 mRNA and other efflux transporters in wildtype and MDR1-transfected MDCK-II and LLC cells. Transcellular transport was measured with the test substrate vinblastine. Key results: In MDR1-transfected MDCK cells, expression of endogenous (canine) Mdr1 and Mrp2 (Abcc2) mRNA was markedly lower than in wildtype cells, whereas MDR1-transfected LLC cells exhibited comparable Mdr1 but strikingly higher Mrp2 mRNA levels than wildtype cells. As a consequence, transport of vinblastine by human Pgp in efflux experiments was markedly underestimated when transport in MDR1-transfected MDCK cells was corrected for transport obtained in wildtype cells. This problem did not occur in LLC cells. Conclusions and implications: Differences in the expression of endogenous efflux transporters between transfected and wildtype MDCK cells provide a potential bias for in vitro studies on Pgp-mediated drug transport. PMID:20590635

  6. Chernobyl radionuclide distribution, migration, and environmental and agricultural impacts.

    PubMed

    Alexakhin, R M; Sanzharova, N I; Fesenko, S V; Spiridonov, S I; Panov, A V

    2007-11-01

    The distribution and migration of radionuclides released into the environment following the Chernobyl accident in 1986 are described. The Chernobyl disaster resulted in the consumption of farm products containing radionuclides as a source of irradiation of the population due to the prevalence of a rural type of human nutrition in the affected region. Economic and radiologic importance of countermeasures for reducing the impacts of the accident are described. The basic radioecological problem is described in which the area where direct radiation contamination of biota was observed is considerably smaller than the zone where concentrations of radionuclides through the food chain exceeded the permissible standards. The radiation-induced effects in biota in the affected area are described. In the long-term post-accident period, the radionuclide distribution between components of ecosystems (including humans) and doses are considered in comparison to a technologically normal situation of nuclear power plant operation. This analysis demonstrates that if radiation standards protect humans, then biota are also adequately protected against ionizing radiation.

  7. Identification of CSF fistulas by radionuclide counting

    SciTech Connect

    Yamamoto, Y.; Kunishio, K.; Sunami, N.; Yamamoto, Y.; Satoh, T.; Suga, M.; Asari, S. )

    1990-07-01

    A radionuclide counting method, performed with the patient prone and the neck flexed, was used successfully to diagnose CSF rhinorrhea in two patients. A normal radionuclide ratio (radionuclide counts in pledget/radionuclide counts in 1-ml blood sample) was obtained in 11 normal control subjects. Significance was determined to be a ratio greater than 0.37. Use of radionuclide counting method of determining CSF rhinorrhea is recommended when other methods have failed to locate a site of leakage or when posttraumatic meningitis suggests subclinical CSF rhinorrhea.

  8. Processes affecting the transport of Cryptosporidium parvum and other persistent pathogens in surface- and ground-waters

    NASA Astrophysics Data System (ADS)

    Packman, A. I.; Lau, B. L.; Harter, T.; Atwill, E. R.

    2007-12-01

    Waterborne diseases are transmitted through numerous environmental pathways, and their migration is strongly mediated by interaction with a wide variety of sediments and other natural materials during transport. Here we provide an overview of factors that affect the fate of persistent water-borne pathogens, focusing particularly on the zoonotic pathogen Cryptosporidium parvum as an example. While individual microbial cells are both small and have low specific gravity, suggesting that they should be highly mobile and remain suspended for long periods of time, attachment to a variety of background materials can substantially reduce pathogen mobility. Cryptosporidium oocysts readily associate with both inorganic and organic particles, resulting in the formation of aggregates. This process tends to increase the effective settling velocity of C. parvum in surface waters. Similarly, pathogens readily become associated with the solid matrix during transport in groundwater, resulting in removal by filtration. However, this process is reversible with C. parvum, resulting in a slow long-term release following the initial deposition. Pathogens also become associated with biofilms, which are surface-attached communities of microorganisms in a gelatinous matrix. The presence of biofilms increases the immobilization and retention of Cryptosporidium on solid surfaces. All of these processes influence pathogen transmission in surface waters such as rivers and water-supply canals. In these environments, pathogens can be immobilized by deposition into stable sediment beds by a combination of gravitational sedimentation and advection into pore waters followed by subsurface filtration. Association with background suspended matter tends to increase pathogen deposition by sedimentation, and the presence of benthic (sedimentary) biofilms also tends to increase pathogen retention. For pathogens that remain viable for long periods of time in natural aquatic systems, as is the case with

  9. Transporters involved in pH and K+ homeostasis affect pollen wall formation, male fertility, and embryo development

    DOE PAGES

    Padmanaban, Senthilkumar; Czerny, Daniel D.; Levin, Kara A.; ...

    2017-02-23

    Flowering plant genomes encode multiple cation/H+ exchangers (CHXs) whose functions are largely unknown. AtCHX17, AtCHX18, and AtCHX19 are membrane transporters that modulate K+ and pH homeostasis and are localized in the dynamic endomembrane system. Loss of function reduced seed set, but the particular phase(s) of reproduction affected was not determined. Pollen tube growth and ovule targeting of chx17chx18chx19 mutant pollen appeared normal, but reciprocal cross experiments indicate a largely male defect. Although triple mutant pollen tubes reach ovules of a wild-type pistil and a synergid cell degenerated, half of those ovules were unfertilized or showed fertilization of the egg ormore » central cell, but not both female gametes. Fertility could be partially compromised by impaired pollen tube and/or sperm function as CHX19 and CHX18 are expressed in the pollen tube and sperm cell, respectively. When fertilization was successful in self-pollinated mutants, early embryo formation was retarded compared with embryos from wild-type ovules receiving mutant pollen. Thus CHX17 and CHX18 proteins may promote embryo development possibly through the endosperm where these genes are expressed. The reticulate pattern of the pollen wall was disorganized in triple mutants, indicating perturbation of wall formation during male gametophyte development. Lastly, as pH and cation homeostasis mediated by AtCHX17 affect membrane trafficking and cargo delivery, these results suggest that male fertility, sperm function, and embryo development are dependent on proper cargo sorting and secretion that remodel cell walls, plasma membranes, and extracellular factors.« less

  10. Parametric studies on confinement of radionuclides in the excavated damaged zone due to bentonite type and temperature change

    NASA Astrophysics Data System (ADS)

    Borrelli, R. A.; Thivent, Olivier; Ahn, Joonhong

    A parametric study is presented in this paper in order to examine the potential of the extruding bentonite into a fracture in the EDZ to confine radionuclides. Radionuclide migration of cesium and neptunium were studied at elevated temperatures and for a sodium- and calcium-type bentonite. Parameter values were obtained based on empirical studies for hydraulic conductivity, molecular diffusion, and sorption. Results indicate extrusion speed is affected by temperature changes. Elevated temperatures also affect radionuclide migration. For Cs, migration is enhanced due to decreasing sorption, while Np migration is inhibited due to increasing sorption. The potential to confine radionuclides is favorable, and the choice of bentonite does not seem to affect radionuclide confinement in the extruding region.

  11. N-glycosylation does not affect the catalytic activity of ricin a chain but stimulates cytotoxicity by promoting its transport out of the endoplasmic reticulum.

    PubMed

    Yan, Qing; Li, Xiao-Ping; Tumer, Nilgun E

    2012-11-01

    Ricin A chain (RTA) depurinates the α-sarcin/ricin loop after it undergoes retrograde trafficking to the cytosol. The structural features of RTA involved in intracellular transport are not known. To explore this, we fused enhanced green fluorescent protein (EGFP) to precursor (preRTA-EGFP), containing a 35-residue leader, and mature RTA (matRTA-EGFP). Both were enzymatically active and toxic in Saccharomyces cerevisiae. PreRTA-EGFP was localized in the endoplasmic reticulum (ER) initially and was subsequently transported to the vacuole, whereas matRTA-EGFP remained in the cytosol, indicating that ER localization is a prerequisite for vacuole transport. When the two glycosylation sites in RTA were mutated, the mature form was fully active and toxic, suggesting that the mutations do not affect catalytic activity. However, nonglycosylated preRTA-EGFP had reduced toxicity, depurination and delayed vacuole transport, indicating that N-glycosylation affects transport of RTA out of the ER. Point mutations in the C-terminal hydrophobic region restricted RTA to the ER and eliminated toxicity and depurination, indicating that this sequence is critical for ER exit. These results demonstrate that N-glycosylation and the C-terminal hydrophobic region stimulate the toxicity of RTA by promoting ER export. The timing of depurination coincided with the timing of vacuole transport, suggesting that RTA may enter the cytosol during vacuole transport.

  12. Numerical modelling of the physical factors that affect mass transport in the vasculature at early time periods.

    PubMed

    Denny, William J; Walsh, Michael T

    2014-03-01

    Coronary artery disease results in blockages or narrowing of the artery lumen. Drug eluting stents were developed to replace bare metal stents in an effort to combat re-blocking of the lumen. A key element in determining the therapeutic success of a drug eluting stent is an in-depth understanding of the physical factors that affect mass transport of the drug into the arterial wall, over early time periods. The numerical models developed within this study focus on assessing the influence of a host of physical factors that either facilitate or impede therapeutic drug delivery into the arterial wall from the unit cell of an idealised stent. This study demonstrates that model reduction strategies to 2D and 1D can still adequately represent a 3D curved arterial wall and strut polymer coating, respectively, using an idealistic stent geometry. It was shown that the level of strut compression can have a significant impact on therapeutic drug delivery in the arterial wall.

  13. Environmental Conditions Influence Induction of Key ABC-Transporter Genes Affecting Glyphosate Resistance Mechanism in Conyza canadensis

    PubMed Central

    Tani, Eleni; Chachalis, Demosthenis; Travlos, Ilias S.; Bilalis, Dimitrios

    2016-01-01

    Conyza canadensis has been reported to be the most frequent weed species that evolved resistance to glyphosate in various parts of the world. The objective of the present study was to investigate the effect of environmental conditions (temperature and light) on the expression levels of the EPSPS gene and two major ABC-transporter genes (M10 and M11) on glyphosate susceptible (GS) and glyphosate resistant (GR) horseweed populations, collected from several regions across Greece. Real-time PCR was conducted to determine the expression level of the aforementioned genes when glyphosate was applied at normal (1×; 533 g·a.e.·ha−1) and high rates (4×, 8×), measured at an early one day after treatment (DAT) and a later stage (four DAT) of expression. Plants were exposed to light or dark conditions, at three temperature regimes (8, 25, 35 °C). GR plants were made sensitive when exposed to 8 °C with light; those sensitized plants behaved biochemically (shikimate accumulation) and molecularly (expression of EPSPS and ABC-genes) like the GS plants. Results from the current study show the direct link between the environmental conditions and the induction level of the above key genes that likely affect the efficiency of the proposed mechanism of glyphosate resistance. PMID:27104532

  14. Gem1 and ERMES do not directly affect phosphatidylserine transport from ER to mitochondria or mitochondrial inheritance.

    PubMed

    Nguyen, Tammy T; Lewandowska, Agnieszka; Choi, Jae-Yeon; Markgraf, Daniel F; Junker, Mirco; Bilgin, Mesut; Ejsing, Christer S; Voelker, Dennis R; Rapoport, Tom A; Shaw, Janet M

    2012-06-01

    In yeast, a protein complex termed the ER-Mitochondria Encounter Structure (ERMES) tethers mitochondria to the endoplasmic reticulum. ERMES proteins are implicated in a variety of cellular functions including phospholipid synthesis, mitochondrial protein import, mitochondrial attachment to actin, polarized mitochondrial movement into daughter cells during division, and maintenance of mitochondrial DNA (mtDNA). The mitochondrial-anchored Gem1 GTPase has been proposed to regulate ERMES functions. Here, we show that ERMES and Gem1 have no direct role in the transport of phosphatidylserine (PS) from the ER to mitochondria during the synthesis of phosphatidylethanolamine (PE), as PS to PE conversion is not affected in ERMES or gem1 mutants. In addition, we report that mitochondrial inheritance defects in ERMES mutants are a secondary consequence of mitochondrial morphology defects, arguing against a primary role for ERMES in mitochondrial association with actin and mitochondrial movement. Finally, we show that ERMES complexes are long-lived, and do not depend on the presence of Gem1. Our findings suggest that the ERMES complex may have primarily a structural role in maintaining mitochondrial morphology.

  15. Environmental Conditions Influence Induction of Key ABC-Transporter Genes Affecting Glyphosate Resistance Mechanism in Conyza canadensis.

    PubMed

    Tani, Eleni; Chachalis, Demosthenis; Travlos, Ilias S; Bilalis, Dimitrios

    2016-04-20

    Conyza canadensis has been reported to be the most frequent weed species that evolved resistance to glyphosate in various parts of the world. The objective of the present study was to investigate the effect of environmental conditions (temperature and light) on the expression levels of the EPSPS gene and two major ABC-transporter genes (M10 and M11) on glyphosate susceptible (GS) and glyphosate resistant (GR) horseweed populations, collected from several regions across Greece. Real-time PCR was conducted to determine the expression level of the aforementioned genes when glyphosate was applied at normal (1×; 533 g·a.e.·ha(-1)) and high rates (4×, 8×), measured at an early one day after treatment (DAT) and a later stage (four DAT) of expression. Plants were exposed to light or dark conditions, at three temperature regimes (8, 25, 35 °C). GR plants were made sensitive when exposed to 8 °C with light; those sensitized plants behaved biochemically (shikimate accumulation) and molecularly (expression of EPSPS and ABC-genes) like the GS plants. Results from the current study show the direct link between the environmental conditions and the induction level of the above key genes that likely affect the efficiency of the proposed mechanism of glyphosate resistance.

  16. Radionuclide synovectomy - essentials for rheumatologists.

    PubMed

    Chojnowski, Marek M; Felis-Giemza, Anna; Kobylecka, Małgorzata

    2016-01-01

    Radionuclide synovectomy is a minimally invasive method of treating persistent joint inflammation. It involves intra-articular injection of radioactive colloids which induce necrosis and fibrosis of hypertrophic synovial membrane. The most common indication for radiosynovectomy is rheumatoid arthritis, although patients with seronegative spondyloarthropathies, unclassified arthritis, haemophilic arthropathy and other less common arthropathies can also benefit from this method. Radiosynovectomy is safe, well tolerated and efficacious. About 70-80% of patients respond well to the therapy. However, the therapeutic effects are considerably worse in patients with co-existent osteoarthritis and advanced joint degeneration. Despite its advantages, radionuclide synovectomy is not performed as often as it could be, so greater knowledge and understanding of this method are needed. The authors present the most important facts about radiosynovectomy that may help rheumatologists in their daily clinical practice.

  17. Factors affecting phosphorus transport at a conventionally-farmed site in Lancaster County, Pennsylvania, 1992-95

    USGS Publications Warehouse

    Galeone, Daniel G.

    1996-01-01

    The U.S. Geological Survey and the Bureau of Land and Water Conservation of the Pennsylvania Department of Environmental Protection conducted a cooperative study to determine the effects of manure application and antecedent soil-phosphorus concentrations on the transport of phosphorus from the soil of a typical farm site in Lancaster County, Pa., from September 1992 to March 1995. The relation between concentrations of soil phosphorus and phosphorus transport needs to be identified because excessive phosphorus concentrations in surface-water bodies promote eutrophication. The objective of the study was to quantify and determine the significance of chemical, physical, and hydrologic factors that affected phosphorus transport. Three study plots less than 1 acre in size were tilled and planted in silage corn. Phosphorus in the form of liquid swine and dairy manure was injected to a depth of 6-8 inches on two of the three study plots in May 1993 and May 1994. Plot 1 received no inputs of phosphorus from manure while plots 2 and 3 received an average of 56 and 126 kilograms of phosphorus per acre, respectively, from the two manure applications. No other fertilizer was applied to any of the study plots. From March 30, 1993, through December 31, 1993, and March 10, 1994, through August 31, 1994 (the study period), phosphorus and selected cations were measured in precipitation, manure, soil, surface runoff, subsurface flow (at 18 inches below land surface), and corn plants before harvest. All storm events that yielded surface runoff and subsurface flow were sampled. Surface runoff was analyzed for dissolved (filtered through a 0.45-micron filter) and total concentrations. Subsurface flow was only analyzed for dissolved constituents. Laboratory soil-flask experiments and geochemical modeling were conducted to determine the maximum phosphate retention capacity of sampled soils after manure applications and primary mineralogic controls in the soils that affect phosphate

  18. Chernobyl radionuclide distribution and migration.

    PubMed

    Izrael, Yury A

    2007-11-01

    The accident at Unit No. 4 of the Chernobyl Nuclear Power Plant on 26 April 1986 presented severe challenges in radiation protection. Early activity measurements defined the contaminated areas in order to determine what persons should be evacuated on the basis of the exposure limit at that time of 100 mSv (10 rem) for accidents. The immediate definition of these areas was accomplished with specially equipped aircraft capable of measuring external gamma-exposure rate and radionuclide spectra. Over time, maps of 137Cs contamination (the most important long-lived radionuclide) have become more and more sophisticated and have been used for further determinations of the control of the consequences of the accident. About 70% of the total release of 137Cs was deposited in Belarus, the Russian Federation, and Ukraine; but there was also widespread deposition throughout the countries of Western Europe. Two atlases of contamination throughout Europe were prepared, and the Russian atlas included data on other radionuclides and on external gamma-exposure rates. The radiocesiums behaved as volatile radionuclides because of the volatility of cesium. In contrast to the typical pattern after nuclear weapons tests, 90Sr behaved only as a refractory element, as its volatile precursors krypton and rubidium had already decayed within the reactor. Nearly all of the refractory elements (strontium, plutonium, etc.) released by the accident were confined to the 30-km zone around the reactor. A proposal is made to develop a more complete atlas of 137Cs deposition from the accident that would include the entire Northern Hemisphere. Water was not an important vector of exposure to human beings following the accident.

  19. Natural chelates for radionuclide decorporation

    DOEpatents

    Premuzic, E.T.

    1983-08-25

    This invention relates to the method and resulting chelates of desorbing a radionuclide selected from thorium, uranium, and plutonium containing cultures in a bioavailable form involving pseudomonas or other microorganisms. A preferred microorganism is Pseudomonas aeruginosa which forms multiple chelates with thorium in the range of molecular weight 1000 to 1000 and also forms chelates with uranium of molecular weight in the area of 100 to 1000 and 1000 to 2000.

  20. Radionuclide behavior in the environment

    SciTech Connect

    Tveten, U. )

    1991-09-01

    The purpose of this report is to document the results of the following task: Review for quality and consistency the available data on measurements of initial ground contamination of Chernobyl radionuclides in various parts of Norway and subsequent concentrations of these radionuclides in various environmental media as functions of time. Utilize the data obtained to verify the existing models, or to improve them, for describing radionuclide behavior in the environment. Some of the processes standard were: migration into soil; weathering; resuspension; food-chain contamination; and loss or reconcentration by run-off. The task performed within this contract has been to use post-Chernobyl data from Norway to verify or find areas for possible improvement in the chronic exposure pathway models utilized in MACCS. Work has consisted mainly of collecting and evaluating post-Chernobyl information from Norway or other countries when relevant; but has also included experimental work performed specifically for the current task. In most connections the data available show the models and data in MACCS to be appropriate. A few areas where the data indicate that the MACCS approach is faulty or inadequate are, however, pointed out in the report. These should be examined carefully, and appropriate modifications should eventually be made. 14 refs., 12 figs., 22 tabs.

  1. Chancellor Water Colloids: Characterization and Radionuclide Association

    SciTech Connect

    Abdel-Fattah, Amr I.

    2012-06-18

    Concluding remarks about this paper are: (1) Gravitational settling, zeta potential, and ultrafiltration data indicate the existence of a colloidal phase of both the alpha and beta emitters in the Chancellor water; (2) The low activity combined with high dispersion homogeneity of the Chancellor water indicate that both alpha and beta emitters are not intrinsic colloids; (3) Radionuclides in the Chancellor water, particularly Pu, coexist as dissolved aqueous and sorbed phases - in other words the radionuclides are partitioned between the aqueous phase and the colloidal phase; (4) The presence of Pu as a dissolved species in the aqueous phase, suggests the possibility of Pu in the (V) oxidation state - this conclusion is supported by the similarity of the k{sub d} value of Pu determined in the current study to that determined for Pu(V) sorbed onto smectite colloids, and the similar electrokinetic behavior of the Chancellor water colloids to smectite colloids; (5) About 50% of the Pu(V) is in the aqueous phase and 50% is sorbed on colloids (mass concentration of colloids in the Chancellor water is 0.12 g/L); (6) The k{sub d} of the Pu and the beta emitters (fission products) between aqueous and colloidal phases in the Chancellor water is {approx}8.0 x 10{sup 3} mL/g using two different activity measurement techniques (LSC and alpha spectroscopy); (7) The gravitational settling and size distributions of the association colloids indicate that the properties (at least the physical ones) of the colloids to which the alpha emitters are associated with seem to be different that the properties of the colloids to which the beta emitters are associated with - the beta emitters are associated with very small particles ({approx}50 - 120 nm), while the alpha emitters are associated with relatively larger particles; and (8) The Chancellor water colloids are extremely stable under the natural pH and ionic strength conditions, indicating high potential for transport in the

  2. Review of Distribution Coefficients for Radionuclides in Carbonate Minerals

    SciTech Connect

    Sutton, M

    2009-08-14

    An understanding of the transport of radionuclides in carbonate minerals is necessary to be able to predict the fate of (and potentially remediate) radionuclides in the environment. In some environments, carbonate minerals such as calciate, aragonite, dolomite and limestone are present and an understanding of the sorption of radionuclides in these carbonate minerals is therefore advantageous. A list of the radionuclides of interest is given in Table 1. The distribution coefficient, K{sub d} is defined as the ratio of the contaminant concentration bound on the solid phase to the contaminant concentration remaining in the liquid phase at equilibrium. Some authors report distribution coefficients and other report partition coefficients, the data presented in this work assumes equality between these two terms, and data are presented and summarized in this work as logarithmic distribution coefficient (log K{sub D}). Published literature was searched using two methods. Firstly, the JNC Sorption Database, namely Shubutani et al (1999), and Suyama and Sasamoto (2004) was used to select elements of interest and a number of carbonate minerals. Secondly, on-line literature search tools were used to locate relevant published articles from 1900 to 2009. Over 300 data points covering 16 elements (hydrogen, carbon, calcium, nickel, strontium, technetium, palladium, iodine, cesium, samarium, europium, holmium, uranium, neptunium, plutonium and americium) were used to calculate an average and range of log K{sub d} values for each element. Unfortunately, no data could be found for chlorine, argon, krypton, zirconium, niobium, tin, thorium and curium. A description of the data is given below, together with the average, standard deviation, minimum, maximum and number of inputs for radionuclide K{sub d} values for calcite, aragonate, limestone, dolomite and unidentified carbonate rocks in Table 2. Finally, the data are condensed into one group (carbonate minerals) of data for each

  3. Arctic Ocean sea ice drift origin derived from artificial radionuclides.

    PubMed

    Cámara-Mor, P; Masqué, P; Garcia-Orellana, J; Cochran, J K; Mas, J L; Chamizo, E; Hanfland, C

    2010-07-15

    Since the 1950s, nuclear weapon testing and releases from the nuclear industry have introduced anthropogenic radionuclides into the sea, and in many instances their ultimate fate are the bottom sediments. The Arctic Ocean is one of the most polluted in this respect, because, in addition to global fallout, it is impacted by regional fallout from nuclear weapon testing, and indirectly by releases from nuclear reprocessing facilities and nuclear accidents. Sea-ice formed in the shallow continental shelves incorporate sediments with variable concentrations of anthropogenic radionuclides that are transported through the Arctic Ocean and are finally released in the melting areas. In this work, we present the results of anthropogenic radionuclide analyses of sea-ice sediments (SIS) collected on five cruises from different Arctic regions and combine them with a database including prior measurements of these radionuclides in SIS. The distribution of (137)Cs and (239,240)Pu activities and the (240)Pu/(239)Pu atom ratio in SIS showed geographical differences, in agreement with the two main sea ice drift patterns derived from the mean field of sea-ice motion, the Transpolar Drift and Beaufort Gyre, with the Fram Strait as the main ablation area. A direct comparison of data measured in SIS samples against those reported for the potential source regions permits identification of the regions from which sea ice incorporates sediments. The (240)Pu/(239)Pu atom ratio in SIS may be used to discern the origin of sea ice from the Kara-Laptev Sea and the Alaskan shelf. However, if the (240)Pu/(239)Pu atom ratio is similar to global fallout, it does not provide a unique diagnostic indicator of the source area, and in such cases, the source of SIS can be constrained with a combination of the (137)Cs and (239,240)Pu activities. Therefore, these anthropogenic radionuclides can be used in many instances to determine the geographical source area of sea-ice.

  4. Microbial transformations of natural organic compounds and radionuclides in subsurface environments

    SciTech Connect

    Francis, A.J.

    1985-10-01

    A major national concern in the subsurface disposal of energy wastes is the contamination of ground and surface waters by waste leachates containing radionuclides, toxic metals, and organic compounds. Microorganisms play an important role in the transformation of organic compounds, radionuclides, and toxic metals present in the waste and affect their mobility in subsurface environments. Microbial processes involved in dissolution, mobilization, and immobilization of toxic metals under aerobic and anaerobic conditions are briefly reviewed. Metal complexing agents and several organic acids produced by microbial action affect mobilization of radionuclides and toxic metals in subsurface environments. Information on the persistence of and biodegradation rates of synthetic as well as microbiologically produced complexing agents is scarce but important in determining the mobility of metal organic complexes in subsoils. Several gaps in knowledge in the area of microbial transformation of naturally occurring organics, radionuclides, and toxic metals have been identified, and further basic research has been suggested. 31 refs., 1 fig., 3 tabs.

  5. Methods of separating short half-life radionuclides from a mixture of radionuclides

    DOEpatents

    Bray, L.A.; Ryan, J.L.

    1998-09-15

    The present invention is a method of obtaining a radionuclide product selected from the group consisting of {sup 223}Ra and {sup 225}Ac, from a radionuclide ``cow`` of {sup 227}Ac or {sup 229}Th respectively. The method comprises the steps of (a) permitting ingrowth of at least one radionuclide daughter from said radionuclide ``cow`` forming an ingrown mixture; (b) insuring that the ingrown mixture is a nitric acid ingrown mixture; (c) passing the nitric acid ingrown mixture through a first nitrate form ion exchange column which permits separating the ``cow`` from at least one radionuclide daughter; (d) insuring that the at least one radionuclide daughter contains the radionuclide product; (e) passing the at least one radionuclide daughter through a second ion exchange column and separating the at least one radionuclide daughter from the radionuclide product and (f) recycling the at least one radionuclide daughter by adding it to the ``cow``. In one embodiment the radionuclide ``cow`` is the {sup 227}Ac, the at least one daughter radionuclide is a {sup 227}Th and the product radionuclide is the {sup 223}Ra and the first nitrate form ion exchange column passes the {sup 227}Ac and retains the {sup 227}Th. In another embodiment the radionuclide ``cow`` is the {sup 229}Th, the at least one daughter radionuclide is a {sup 225}Ra and said product radionuclide is the {sup 225}Ac and the {sup 225}Ac and nitrate form ion exchange column retains the {sup 229}Th and passes the {sup 225}Ra/Ac. 8 figs.

  6. Methods of separating short half-life radionuclides from a mixture of radionuclides

    DOEpatents

    Bray, Lane A.; Ryan, Jack L.

    1998-01-01

    The present invention is a method of obtaining a radionuclide product selected from the group consisting of .sup.223 Ra and .sup.225 Ac, from a radionuclide "cow" of .sup.227 Ac or .sup.229 Th respectively. The method comprises the steps of a) permitting ingrowth of at least one radionuclide daughter from said radionuclide "cow" forming an ingrown mixture; b) insuring that the ingrown mixture is a nitric acid ingrown mixture; c) passing the nitric acid ingrown mixture through a first nitrate form ion exchange column which permits separating the "cow" from at least one radionuclide daughter; d) insuring that the at least one radionuclide daughter contains the radionuclide product; e) passing the at least one radionuclide daughter through a second ion exchange column and separating the at least one radionuclide daughter from the radionuclide product and f) recycling the at least one radionuclide daughter by adding it to the "cow". In one embodiment the radionuclide "cow" is the .sup.227 Ac, the at least one daughter radionuclide is a .sup.227 Th and the product radionuclide is the .sup.223 Ra and the first nitrate form ion exchange column passes the .sup.227 Ac and retains the .sup.227 Th. In another embodiment the radionuclide "cow"is the .sup.229 Th, the at least one daughter radionuclide is a .sup.225 Ra and said product radionuclide is the .sup.225 Ac and the .sup.225 Ac and nitrate form ion exchange column retains the .sup.229 Th and passes the .sup.225 Ra/Ac.

  7. Optimizing diagnosis in Parkinson's disease: Radionuclide imaging.

    PubMed

    Arena, Julieta E; Stoessl, A Jon

    2016-01-01

    Parkinson's disease (PD) and other disorders characterized by basal ganglia dysfunction are often associated with limited structural imaging changes that might assist in the clinical or research setting. Radionuclide imaging has been used to assess characteristic functional changes. Presynaptic dopaminergic dysfunction in PD can be revealed through the imaging of different steps in the process of dopamine synthesis and storage: L-aromatic amino acid decarboxylase (AADC) activity, Vesicular Monoamine Transporter type 2 (VMAT2) binding or its reuptake via the dopamine transporter (DAT). Postsynaptic dopamine dysfunction can also be studied with a variety of different tracers that primarily assess D2-like dopamine receptor availability. The function of other neurotransmitters such as norepinephrine, serotonin and acetylcholine can be imaged as well, giving important information about the underlying pathophysiologic process of PD and its complications. The imaging of metabolic activity and pathologic changes has also provided great advances in the field. Together, these techniques have allowed for a better understanding of PD, may be of aid for differentiating PD from other forms of parkinsonism and will undoubtedly be useful for the establishment of new therapeutic targets.

  8. Simple model for the reconstruction of radionuclide concentrations and radiation exposures along the Techa River

    NASA Technical Reports Server (NTRS)

    Vorobiova, M. I.; Degteva, M. O.; Neta, M. O. (Principal Investigator)

    1999-01-01

    The Techa River (Southern Urals, Russia) was contaminated in 1949-1956 by liquid radioactive wastes from the Mayak complex, the first Russian facility for the production of plutonium. The measurements of environmental contamination were started in 1951. A simple model describing radionuclide transport along the free-flowing river and the accumulation of radionuclides by bottom sediments is presented. This model successfully correlates the rates of radionuclide releases as reconstructed by the Mayak experts, hydrological data, and available environmental monitoring data for the early period of contamination (1949-1951). The model was developed to reconstruct doses for people who lived in the riverside communities during the period of the releases and who were chronically exposed to external and internal irradiation. The model fills the data gaps and permits reconstruction of external gamma-exposure rates in air on the river bank and radionuclide concentrations in river water used for drinking and other household needs in 1949-1951.

  9. Environmental Baseline File: National Transportation

    SciTech Connect

    1999-05-22

    This Environmental Baseline File summarizes and consolidates information related to the national-level transportation of commercial spent nuclear fuel. Topics address include: shipmnents of commercial spent nuclear fuel based on mostly truck and mostly rail shipping scenarios; transportation routing for commercial spent nuclear fuel sites and DOE sites; radionuclide inventories for various shipping container capacities; transportation routing; populations along transportation routes; urbanized area population densities; the impacts of historical, reasonably foreseeable, and general transportation; state-level food transfer factors; Federal Guidance Report No. 11 and 12 radionuclide dose conversion factors; and national average atmospheric conditions.

  10. Probabilistic distribution coefficients (K(d)s) in freshwater for radioisotopes of Ag, Am, Ba, Be, Ce, Co, Cs, I, Mn, Pu, Ra, Ru, Sb, Sr and Th: implications for uncertainty analysis of models simulating the transport of radionuclides in rivers.

    PubMed

    Ciffroy, P; Durrieu, G; Garnier, J-M

    2009-09-01

    The objective of this study was to provide operational probability density functions (PDFs) for distribution coefficients (K(d)s) in freshwater, representing the partition of radionuclides between the particulate and the dissolved phases respectively. Accordingly, the K(d) variability should be considered in uncertainty analysis of transport and risk assessment models. The construction of PDFs for 8 elements (Ag, Am, Co, Cs, I, Mn, Pu and Sr) was established according to the procedure already tested in Durrieu et al. [2006. A weighted bootstrap method for the determination of probability density functions of freshwater distribution coefficients (K(d)s) of Co, Cs, Sr and I radioisotopes. Chemosphere 65 (8), 1308-1320]: (i) construction of a comprehensive database where K(d)s values obtained under various environments and parametric conditions were collected; (ii) scoring procedure to account for the 'quality' of each datapoint (according to several criteria such as the presentation of data (e.g. raw data vs mean with or without replicates), contact time, pH, solid-to-liquid ratio, expert judgement) in the construction of the PDF; (iii) weighted bootstrapping procedure to build the PDFs, in order to give more importance to the most relevant datapoints. Two types of PDFs were constructed: (i) non-conditional, usable when no knowledge about the site of concern is available; (ii) conditional PDFs corresponding to a limited range of parameters such as pH or contact time; conditional PDFs can thus be used when some parametric information is known on the site under study. For 7 other radionuclides (Ba, Be, Ce, Ra, Ru, Sb and Th), a simplified procedure was adopted because of the scarcity of data: only non-conditional PDFs were built, without incorporating a scoring procedure.

  11. Targeted Radionuclide Therapy of Human Tumors

    PubMed Central

    Gudkov, Sergey V.; Shilyagina, Natalya Yu.; Vodeneev, Vladimir A.; Zvyagin, Andrei V.

    2015-01-01

    Targeted radionuclide therapy is one of the most intensively developing directions of nuclear medicine. Unlike conventional external beam therapy, the targeted radionuclide therapy causes less collateral damage to normal tissues and allows targeted drug delivery to a clinically diagnosed neoplastic malformations, as well as metastasized cells and cellular clusters, thus providing systemic therapy of cancer. The methods of targeted radionuclide therapy are based on the use of molecular carriers of radionuclides with high affinity to antigens on the surface of tumor cells. The potential of targeted radionuclide therapy has markedly grown nowadays due to the expanded knowledge base in cancer biology, bioengineering, and radiochemistry. In this review, progress in the radionuclide therapy of hematological malignancies and approaches for treatment of solid tumors is addressed. PMID:26729091

  12. Dopamine transporter DAT and receptor DRD2 variants affect risk of lethal cocaine abuse: a gene–gene–environment interaction

    PubMed Central

    Sullivan, D; Pinsonneault, J K; Papp, A C; Zhu, H; Lemeshow, S; Mash, D C; Sadee, W

    2013-01-01

    Epistatic gene–gene interactions could contribute to the heritability of complex multigenic disorders, but few examples have been reported. Here, we focus on the role of aberrant dopaminergic signaling, involving the dopamine transporter DAT, a cocaine target, and the dopamine D2 receptor, which physically interacts with DAT. Splicing polymorphism rs2283265 of DRD2, encoding D2 receptors, were shown to confer risk of cocaine overdose/death (odds ratio ∼3) in subjects and controls from the Miami Dade County Brain Bank.1 Risk of cocaine-related death attributable to the minor allele of rs2283265 was significantly enhanced to OR=7.5 (P=0.0008) in homozygous carriers of the main 6-repeat allele of DAT rs3836790, a regulatory VNTR in intron8 lacking significant effect itself. In contrast, carriers of the minor 5-repeat DAT allele showed no significant risk (OR=1.1, P=0.84). DAT rs3836790 and DRD2 rs2283265 also interacted by modulating DAT protein activity in the ventral putamen of cocaine abusers. In high-linkage disequilibrium with the VNTR, DAT rs6347 in exon9 yielded similar results. Assessing the impact of DAT alone, a rare DAT haplotype formed by the minor alleles of rs3836790 and rs27072, a regulatory DAT variant in the 3′-UTR, occurred in nearly one-third of the cocaine abusers but was absent in African American controls, apparently conferring strong risk. These results demonstrate gene–gene–drug interaction affecting risk of fatal cocaine intoxication. PMID:23340505

  13. How AGN and SN Feedback Affect Mass Transport and Black Hole Growth in High-redshift Galaxies

    NASA Astrophysics Data System (ADS)

    Prieto, Joaquin; Escala, Andrés; Volonteri, Marta; Dubois, Yohan

    2017-02-01

    Using cosmological hydrodynamical simulations, we study the effect of supernova (SN) and active galactic nucleus (AGN) feedback on the mass transport (MT) of gas onto galactic nuclei and the black hole (BH) growth down to redshift z∼ 6. We study the BH growth in relation to the MT processes associated with gravity and pressure torques and how they are modified by feedback. Cosmological gas funneled through cold flows reaches the galactic outer region close to freefall. Then torques associated with pressure triggered by gas turbulent motions produced in the circumgalactic medium by shocks and explosions from SNe are the main source of MT beyond the central ∼100 pc. Due to high concentrations of mass in the central galactic region, gravitational torques tend to be more important at high redshift. The combined effect of almost freefalling material and both gravity and pressure torques produces a mass accretion rate of order ∼ 1 {M}ȯ yr‑1 at approximately parsec scales. In the absence of SN feedback, AGN feedback alone does not affect significantly either star formation or BH growth until the BH reaches a sufficiently high mass of ∼ {10}6 {M}ȯ to self-regulate. SN feedback alone, instead, decreases both stellar and BH growth. Finally, SN and AGN feedback in tandem efficiently quench the BH growth, while star formation remains at the levels set by SN feedback alone, due to the small final BH mass, ∼few times {10}5 {M}ȯ . SNe create a more rarefied and hot environment where energy injection from the central AGN can accelerate the gas further.

  14. A multi-radionuclide approach to evaluate the suitability of (239+240)Pu as soil erosion tracer.

    PubMed

    Meusburger, Katrin; Mabit, Lionel; Ketterer, Michael; Park, Ji-Hyung; Sandor, Tarjan; Porto, Paolo; Alewell, Christine

    2016-10-01

    Fallout radionuclides have been used successfully worldwide as tracers for soil erosion, but relatively few studies exploit the full potential of plutonium (Pu) isotopes. Hence, this study aims to explore the suitability of the plutonium isotopes (239)Pu and (240)Pu as a method to assess soil erosion magnitude by comparison to more established fallout radionuclides such as (137)Cs and (210)Pbex. As test area an erosion affected headwater catchment of the Lake Soyang (South Korea) was selected. All three fallout radionuclides confirmed high erosion rates for agricultural sites (>25tha(-1)yr(-1)). Pu isotopes further allowed determining the origin of the fallout. Both (240)Pu/(239)Pu atomic ratios and (239+240)Pu/(137)Cs activity ratios were close to the global fallout ratio. How