Science.gov

Sample records for affect 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

    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

  5. 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

  6. 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

  7. 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.

  8. Radionuclide transport through engineered barrier system alteration products

    SciTech Connect

    Viani, B.E.; Torretto, P.C.; Matzen, S.L.

    1997-12-01

    The primary rationale for studying the transport behavior of radionuclides through the Engineered Barrier system / Near Field Environment (EBS/NFE) is to ascertain whether the material properties of the introduced and altered host rock can significantly affect the transport of radionuclides from the waste container to the far field. The intent of this report is to present data and modeling results that can be used to assess the importance of canister corrosion products and cementitious materials to transport of radionuclides to the far field.

  9. 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.

  10. Radionuclide transport coupled with bentonite extrusion in a saturated fracture system

    NASA Astrophysics Data System (ADS)

    Borrelli, Robert Angelo

    The study in this dissertation focuses on the characterization of radionuclide migration in a water saturated fracture. The near field of a high level radioactive waste repository contains the engineered barrier system, which provides manufactured components designed to limit radionuclide releases to the environment. A major component in this system involves the utilization of bentonite as a buffer to protect the degraded waste package and limit release of radionuclides into intersecting fractures that pose possible pathways for transport to the environment. A model is derived for radionuclide migration through this fracture. The model incorporates the features of bentonite: extrusion into the fracture, sorption, and the effect of bentonite swelling on groundwater flow. The resulting derivation of this model is a coupled system of differential equations. The differential equation describing the mass conservation of radionuclides is coupled to the equation system for bentonite extrusion. The models are coupled through the parameters in the radionuclide transport model, which are dependent on the spatial distribution of solid material in the domain. Numerical evaluations of the solution to this radionuclide transport model were conducted for neptunium, a weakly sorbing radionuclide and americium, a strongly sorbing radionuclide. Results were presented in terms normalized spatial distribution of radionuclide concentration in the fluid phase and normalized radionuclide release rate in the fluid phase. Major findings of the study conducted for this dissertation are provided. (1) Bentonite extrusion affects fluid phase advection resulting in groundwater flow countercurrent to the direction of extrusion to the direction of radionuclide migration. (2) The sorption distribution coefficient is the most important parameter affecting radionuclide behavior in this system for this model. (3) Simulations of the model for americium, a highly sorbing radionuclide, indicate that

  11. 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.

  12. Radionuclide transport and retardation in tuff

    SciTech Connect

    Vine, E.N.; Bayhurst, B.P.; Daniels, W.R.; DeVilliers, S.J.; Erdal, B.R.; Lawrence, F.O.; Wolfsberg, K.

    1980-12-31

    Batch measurements provide an understanding of which experimental variables are important. For example, sorption ratios vary little with particle size (and surface area); however, groundwater composition and rock composition are quite important. A general correlation has been identified between mineralogy (major phases) and degree of sorption for strontium, cesium, and barium. Although these are approximate, a more detailed analysis may be possible as more samples are studied and the data base increased. Data from crushed tuff columns indicate that, except in simple cases where sorption coefficients are relatively low, and ion-exchange equilibria not only exist but are the dominant mechanism for removal of radioisotopes from solution, the simple relation between the sorption ratio R/sub d/ (or K/sub d/) and the relative velocity of radionuclides with respect to groundwater velocity may be insufficient to permit accurate modeling of the retardation of radionuclides. Additional work on whole core columns and larger blocks of intact material is required to better understand radionuclide sorption and transport through rock.

  13. 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.

  14. 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

  15. 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

  16. 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.

  17. 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

  18. 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. PMID:24571606

  19. 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.

  20. 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.

  1. 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.

  2. Mass transfer and transport of radionuclides in fractured porous rock

    SciTech Connect

    Ahn, Joonhong

    1988-04-01

    Analytical studies are made to predict space-time dependent concentrations of radionuclides transported through water-saturated fractured porous rock. A basic model, which is expected to generate conservative results when used in long-term safety assessment of geologic repositories for radioactive waste, is established. Applicability and limitations of the model are investigated. 67 refs., 54 figs., 3 tabs.

  3. 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.

  4. Evidence for radionuclide transport by sea ice

    USGS Publications Warehouse

    Meese, D.A.; Reimnitz, E.; Tucker, W. B.; Gow, A.J.; Bischof, J.; Darby, D.

    1997-01-01

    Ice and ice-borne sediments were collected across the Arctic Basin during the Arctic Ocean Section, 1994 (AOS-94), a recent US/Canada trans- Arctic expedition. Sediments were analysed for 137Cs, clay mineralogy and carbon. Concentrations of 137Cs ranged from 5 to 73 Bq kg-1 in the ice- borne sediments. Concentrations of ice samples without sediment were all less than 1 Bq m-3. The sediment sample with the highest 137Cs concentration (73 Bq kg-1)was collected in the Beaufort Sea. This concentration was significantly higher than in bottom sediments collected in the same area, indicating an ice transport mechanism from an area with correspondingly higher concentrations. Recent results from the application of ice transport models and sediment analyses indicate that it is very likely that sediments are transported by ice, from the Siberian shelf areas to the Beaufort Sea.

  5. 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.

  6. Radionuclide Transport Models Under Ambient Conditions

    SciTech Connect

    G. Moridis; Q. Hu

    2001-12-20

    The purpose of Revision 00 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.

  7. Radionuclide transport in sandstones with WIPP brine

    SciTech Connect

    Weed, H.C.; Bazan, F.; Fontanilla, J.; Garrison, J.; Rego, J.; Winslow, A.M.

    1981-02-01

    Retardation factors (R) have been measured for the transport of /sup 3/H, /sup 95m/Tc, and /sup 85/Sr in WIPP brine using St. Peter, Berea, Kayenta, and San Felipe sandstone cores. If tritium is assumed to have R=1, /sup 95m/Tc has R=1.0 to 1.3 and therefore is essentially not retarded. Strontium-85 has R = 1.0 to 1.3 on St. Peter, Berea, and Kayenta, but R=3 on San Felipe. This is attributed to sorption on the matrix material of San Felipe, which has 45 volume % matrix compared with 1 to 10 volume % for the others. Retardation factors (R/sub s/) for /sup 85/Sr calculated from static sorption measurements are unity for all the sandstones. Therefore, the static and transport results for /sup 85/Sr disagree in the case of San Felipe, but agree for St. Peter, Berea, and Kayenta.

  8. GIS Modelling of Radionuclide Transport from the Semipalatinsk Test Site

    NASA Astrophysics Data System (ADS)

    Balakay, L.; Zakarin, E.; Mahura, A.; Baklanov, A.; Sorensen, J. H.

    2009-04-01

    In this study, the software complex GIS-project MigRad (Migration of Radionuclide) was developed, tested and applied for the territory of the Semipalatinsk test site/ polygon (Republic of Kazakhstan), where since 1961, in total 348 underground nuclear explosions were conducted. The MigRad is oriented on integration of large volumes of different information (mapping, ground-based, and satellite-based survey): and also includes modeling on its base local redistribution of radionuclides by precipitation and surface waters and by long-range transport of radioactive aerosols. The existing thermal anomaly on territory of the polygon was investigated in details, and the object-oriented analysis was applied for the studied area. Employing the RUNOFF model, the simulation of radionuclides migration with surface waters was performed. Employing the DERMA model, the simulation of long-term atmospheric transport, dispersion and deposition patterns for cesium was conducted from 3 selected locations (Balapan, Delegen, and Experimental Field). Employing geoinformation technology, the mapping of the of the high temperature zones and epicenters of radioactive aerosols transport for the territory of the test site was carried out with post-processing and integration of modelling results into GIS environment. Contamination levels of pollution due to former nuclear explosions for population and environment of the surrounding polygon territories of Kazakhstan as well as adjacent countries were analyzed and evaluated. The MigRad was designed as instrument for comprehensive analysis of complex territorial processes influenced by former nuclear explosions on the territory of Semipalatinsk test site. It provides possibilities in detailed analyses for (i) extensive cartographic material, remote sensing, and field measurements data collected in different level databases; (ii) radionuclide migration with flows using accumulation and redistribution of soil particles; (iii) thermal anomalies

  9. 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.

  10. ITE CHARACTERIZATION TO SUPPORT CONCEPTUAL MODEL DEVELOPMENT FOR SUBSURFACE RADIONUCLIDE TRANSPORT

    EPA Science Inventory

    Remediation of radionuclide contaminants in ground water often begins with the development of conceptual and analytical models that guide our understanding of the processes controlling radionuclide transport. The reliability of these models is often predicated on the collection o...

  11. The 41Ca bomb pulse and atmospheric transport of radionuclides

    NASA Astrophysics Data System (ADS)

    Zerle, L.; Faestermann, T.; Knie, K.; Korschinek, G.; Nolte, E.; Beer, J.; Schotterer, U.

    1997-08-01

    For the first time, the 41Ca signal from the nuclear weapon tests has been measured. Calcium 41 concentrations have been determined in alpine ice of the Fiescherhorn glacier (Switzerland) with accelerator mass spectrometry. The peak concentrations have been observed to be about 3×106 atoms of 41Ca per kilogram of ice in. the 1950s. It has been found that 41Ca is produced essentially by the atoll bombs. A universal box model, able to describe atmospheric transport of radionuclides that are in gaseous form or attached to aerosols, has been developed. The model has been applied to calculate the bomb pulses of 14C, 36Cl, 41Ca, 90Sr, and 137Cs, For the transport of radionuclides that are attached to aerosols such as 41Ca, 90Sr, and 137Cs, sedimentation (gravitational settling) in the upper stratosphere has been taken into account. It has been found that the deposition of bomb-produced 36Cl on the Earth's surface is delayed compared to that of 90Sr by about 1 year because 36Cl stays gaseous in the stratosphere. The model can also be used to calculate the deposition of cosmogenic radionuclides, e.g., 36Cl and 10Be, in their natural archives, such as polar ice sheets.

  12. Simulating Effects of Non-Isothermal Flow on Reactive Transport of Radionuclides Originating from an Underground Nuclear Test

    SciTech Connect

    Carle, S F; Zavarin, M; Shumaker, D E; Tompson, A B; Maxwell, R M; Pawloski, G A

    2006-03-06

    Temperature can significantly affect radionuclide transport behavior. In simulation of radionuclide transport originating from an underground nuclear test, temperature effects from residual test heat include non-isothermal groundwater flow behavior (e.g. convection cells), increased dissolution rates of melt glass containing refractory radionuclides, changes in water chemistry, and, in turn, changes in radionuclide sorption behavior. The low-yield (0.75 kiloton) Cambric underground nuclear test situated in alluvium below the water table offers unique perspectives on radionuclide transport in groundwater. The Cambric test was followed by extensive post-test characterization of the radionuclide source term and a 16-year pumping-induced radionuclide migration experiment that captured more mobile radionuclides in groundwater. Discharge of pumped groundwater caused inadvertent recirculation of radionuclides through a 220-m thick vadose zone to the water table and below, including partial re-capture in the pumping well. Non-isothermal flow simulations indicate test-related heat persists at Cambric for about 10 years and induces limited thermal convection of groundwater. The test heat has relatively little impact on mobilizing radionuclides compared to subsequent pumping effects. However, our reactive transport models indicate test-related heat can raise melt glass dissolution rates up to 10{sup 4} faster than at ambient temperatures depending on pH and species activities. Non-isothermal flow simulations indicate that these elevated glass dissolution rates largely decrease within 1 year. Thermally-induced increases in fluid velocity may also significantly increase rates of melt glass dissolution by changing the fluid chemistry in contact with the dissolving glass.

  13. Nanostructures and radionuclide transport in clay formations (Invited)

    NASA Astrophysics Data System (ADS)

    Wang, Y.

    2010-12-01

    Nanostructures are widely present in geologic materials and are expected to directly affect the interactions of these materials with geologic fluids. The study of mineral-water interface chemistry as controlled by nanostructures is a necessary step to bridge the existing gap between the molecular level understanding of a geochemical process and the macro-scale laboratory and field observations. In this presentation, I will review the recent progresses in nanoscience and provide a perspective on how these progresses can potentially impact geochemical studies. My presentation will be focused the following areas: (1) the characterization of nanostructures in natural systems, (2) the study of water and chemical species in nanoconfinement, (3) the effects of nanopores on geochemical reaction and mass transfers, and (4) the use nanostructured materials for environmental remediation and cleanup. Specifically, I will demonstrate that the nanopore confinement can significantly modify geochemical reactions in porous geologic media. As the pore size is reduced to a few nanometers, the difference between surface acidity constants (pK2 - pK1) decreases, giving rise to a higher surface charge density on a nanopore surface than that on an unconfined mineral-water interface. The change in surface acidity constants results in a shift of ion sorption edges and enhances ion sorption on nanopore surfaces. This effect causes preferential enrichment of trace elements in nanopores and therefore directly impacts the bioavailability of these elements. The implication of these processes to radionuclide transport in clay formations will be discussed. This work was performed at Sandia National Laboratories, which is a multiprogram laboratory operated by Sandia Corporation, a Lockheed-Martin Company, for the DOE under contract DE-AC04-94AL8500.

  14. Colloid-Facilitated Radionuclide Transport at the Potential Yucca Mountain Repository

    NASA Astrophysics Data System (ADS)

    Alcorn, S. R.; Mertz, C. J.

    2001-12-01

    In a geologic repository for nuclear waste, transport of radionuclides on or within colloids may be important for radionuclides of concern that have low solubility and can be entrained in, or sorbed onto, colloidal particles generated within the repository system. It is anticipated that colloids will be formed and mobilized at the potential Yucca Mountain repository as a result of alteration of high-level radioactive waste (HLW) and spent nuclear fuel (SNF) waste forms, as well as corrosion of engineered barrier system (EBS) components. The abundance of colloids leaving a breached waste package and entering the repository drift will depend on the extent of waste form and EBS component alteration and the alteration products formed. Further, colloid abundance and stability will depend on such environmental factors as the ionic strength, pH, cation concentrations, natural colloid content, and organic acid and microbe content of groundwater entering the waste package from the drift. Colloids may flocculate and settle, be chemically retarded, mechanically filtered, or dissolve. In addition, colloids may sorb readily at the interfaces between air and water in rocks and engineered barriers and, depending upon the characteristics and degree of saturation of the porous medium, may be immobilized, retarded, or transported. A methodology for modeling colloid-facilitated radionuclide transport in the potential repository at Yucca Mountain was developed for use in Total System Performance Assessment calculations. The model incorporates several colloid sources and addresses factors affecting colloid stability and concentration as well as distribution and attachment of radionuclides onto colloids. Waste form corrosion tests performed at Argonne National Laboratory (ANL) have focused on determination of colloid composition, stability, concentration, size distribution, and associated radionuclide concentration. Data from these experiments were used as model inputs.

  15. Laboratory studies of radionuclide transport in fractured Climax granite

    SciTech Connect

    Failor, R.; Isherwood, D.; Raber, E.; Vandergraaf, T.

    1982-06-01

    This report documents our laboratory studies of radionuclide transport in fractured granite cores. To simulate natural conditions, our laboratory studies used naturally fractured cores and natural ground water from the Climax Granite Stock at the Nevada Test Site. For comparison, additional tests used artificially fractured granite cores or distilled water. Relative to the flow of tritiated water, {sup 85}Sr and /sup 95m/Tc showed little or no retardation, whereas {sup 137}Cs was retarded. After the transport runs the cores retained varying amounts of the injected radionuclides along the fracture. Autoradiography revealed some correlation between sorption and the fracture fill material. Strontium and cesium retention increased when the change was made from natural ground water to distilled water. Artificial fractures retained less {sup 137}Cs than most natural fractures. Estimated fracture apertures from 18 to 60 {mu}m and hydraulic conductivities from 1.7 to 26 x 10{sup -3} m/s were calculated from the core measurements.

  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. Assessment of hydrologic transport of radionuclides from the Gasbuggy underground nuclear test site, New Mexico

    SciTech Connect

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

    1996-09-01

    The U.S. Department of Energy (DOE) is operating an environmental restoration program to characterize, remediate, and close non-Nevada Test Site locations that were used for nuclear testing. Evaluation of radionuclide transport by groundwater from these sites is an important part of the preliminary risk analysis. These evaluations are undertaken to allow prioritization of the test areas in terms of risk, provide a quantitative basis for discussions with regulators and the public about future work at the sites, and provide a framework for assessing data needs to be filled by site characterization. The Gasbuggy site in northwestern New Mexico was the location of an underground detonation of a 29-kiloton nuclear device in 1967. The test took place in the Lewis Shale, approximately 182 m below the Ojo Alamo Sandstone, which is the aquifer closest to the detonation horizon. The conservative assumption was made that tritium was injected from the blast-created cavity into the Ojo Alamo Sandstone by the force of the explosion, via fractures created by the shot. Model results suggest that if radionuclides produced by the shot entered the Ojo Alamo, they are most likely contained within the area currently administered by DOE. The transport calculations are most sensitive to changes in the mean groundwater velocity, followed by the variance in hydraulic conductivity, the correlation scale of hydraulic conductivity, the transverse hydrodynamic dispersion coefficient, and uncertainty in the source size. This modeling was performed to investigate how the uncertainty in various physical parameters affects calculations of radionuclide transport at the Gasbuggy site, and to serve as a starting point for discussion regarding further investigation at the site; it was not intended to be a definitive simulation of migration pathways or radionuclide concentration values.

  18. 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.

  19. 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).

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

    PubMed

    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

  1. 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

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

    DOE PAGES

    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 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

    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. Seasonal and location-based effects on breakthrough, which occur due to differences in barometric forcing, are stronger where the barometric signal is highly variable.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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...

  12. Seepage basin radionuclide transport in sediments and vegetation. Revision 1

    SciTech Connect

    Murphy, C.E. Jr.; Jerome, K.M.

    1993-12-31

    Radionuclide concentrations were measured in soil and vegetation growing adjacent to and in the Savannah River Laboratory Seepage Basins as part of the plan for closure of the basin system. The results of the measurements provide some information about the mobility of the radionuclides introduced into the basins. {sup 90}Sr is the most mobile of the radionuclides in soil. Its high mobility and high relative uptake by vegetation cause {sup 90}Sr to be distributed throughout the basin system. {sup 137}Cs is not as mobile in the basin soil, limiting its uptake by vegetation growing on the edge of the seepage basins; however, it is readily taken up by the vegetation growing in the basins. Soil mobility and vegetation uptake is relatively low for all of the transuranic radionuclides. For the most part these radionuclides remain near the surface of the basin soils where they were absorbed from the waste-water. The relative role of soil mobility and vegetation uptake on the distribution of radionuclide at the basins was futher evaluated by comparing the vegetation concentration ratio and the half-depth of penetration of the radionuclides in the basin soil. The results suggest that vegetation processes dominate in determining the concentration of {sup 60}Co and {sup 137}Cs in the vegetation. The influences of soil and vegetation are more balanced for {sup 90}Sr. The other radionuclides exhibit both low soil mobility and low vegetation uptake. The lack of soil mobility is seen in the lower concentrations found in vegetation growing on the edge of the basin compared to those growing in the basin.

  13. Analytical solutions for reactive transport of N-member radionuclide chains in a single fracture.

    PubMed

    Sun, Yunwei; Buscheck, Thomas A

    2003-01-01

    Several numerical codes have been used to simulate radionuclide transport in fractured rock systems. The validation of such numerical codes can be accomplished by comparison of numerical simulations against appropriate analytical solutions. In this paper, we present analytical solutions for the reactive transport of N-member radionuclide chains (i.e., multiple species of radionuclides and their daughter species) through a discrete fracture in a porous rock matrix applying a system decomposition approach. We consider the transport of N-member radionuclide chains in a single-fracture-matrix system as a starting point to simulate more realistic and complex systems. The processes considered are advection along the fracture, lateral diffusion in the matrix, radioactive decay of multiple radionuclides, and adsorption in both the fracture and matrix. Different retardation factors can be specified for the fracture and matrix. However, all species are assumed to share the same retardation factors for the fracture and matrix, respectively. Although a daughter species may penetrate farther along the fracture than its parent species when a constant-concentration boundary condition is applied, our results indicate that all species retain the same transport speed in the fracture if a pulse of the first species is released into the fracture. This solution scheme provides a way to validate numerical computer codes of radionuclide transport in fractured rock, such as those being used to assess the performance of a potential nuclear-waste repository at Yucca Mountain.

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

    PubMed

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

    2012-06-12

    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 (134)Cs (4.0 ± 1.4 Bq kg(-1)) and elevated (137)Cs (6.3 ± 1.5 Bq kg(-1)) in 15 Pacific bluefin tuna sampled in August 2011. We found no (134)Cs and background concentrations (~1 Bq kg(-1)) of (137)Cs 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 (134)Cs) and potentially migration timing (using (134)Cs:(137)Cs ratios) in highly migratory marine species in the Pacific Ocean. PMID:22645346

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

    PubMed

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

    2012-06-12

    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 (134)Cs (4.0 ± 1.4 Bq kg(-1)) and elevated (137)Cs (6.3 ± 1.5 Bq kg(-1)) in 15 Pacific bluefin tuna sampled in August 2011. We found no (134)Cs and background concentrations (~1 Bq kg(-1)) of (137)Cs 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 (134)Cs) and potentially migration timing (using (134)Cs:(137)Cs ratios) in highly migratory marine species in the Pacific Ocean.

  16. 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.

  17. Travel time simulation for radionuclide transport at the Korean underground research facility, KURT

    NASA Astrophysics Data System (ADS)

    Ko, N.; Hwang, Y.; Jeong, J.; Kim, K.

    2013-12-01

    For the research on the deep geological disposal of radioactive waste, it is necessary to understand the underground environment, including the geology and hydrogeology. In Korea, KURT (KAERI Underground Research Tunnel) was constructed in 2006 at KAERI (Korea Atomic Energy Research Institute). Geological and hydrogeological field data have been obtained from the facility, and the groundwater flow system was simulated. Based on the data observed and analyzed on a groundwater flow system, the transport of potential radionuclides, which were assumed to be released at the supposed position, was then calculated in order to prepare the fundamental data for a safety assessment of a hypothetical underground repository. Several pathways with highly water-conductive features were selected to evaluate the elapsed times of radionuclide transport. The transport times were calculated using a TDRW (Time-Domain Random Walk) method. The matrix diffusion and sorption mechanisms in the host rock, as well as the advection-dispersion processes, were considered under the KURT field conditions. To reflect the radioactive decay, some decay chains were selected. The simulation results indicate that the main factors for the shapes of the mass discharge of the radionuclides were the half-life and distribution coefficient. This shows that the long-lived radionuclides must be treated accurately at the steps of determining radioactive waste source term as well as considering the transport process, and intensified research is required for the sorption between radionuclides and host rocks for making the safety assessment process more reliable and less uncertain.

  18. 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.

  19. Transport simulation of the radionuclide from the shelf to open ocean around Fukushima

    NASA Astrophysics Data System (ADS)

    Miyazawa, Yasumasa; Masumoto, Yukio; Varlamov, Sergey M.; Miyama, Toru

    2012-12-01

    We simulate radionuclide distribution in the ocean due to direct emission from the Fukushima Daiichi nuclear power plant (FNPP) for the period from 21 March to 6 May 2011. Dispersion of Cesium-137 is modeled by a transport equation with advection and diffusion by three dimensional ocean current. The ocean current data are provided from a data-assimilative, tide-resolving ocean general circulation model with horizontal resolution of 1/36°. Results show that the radionuclide expands from the shelf region into open ocean in April by the ocean currents and farther transported eastward along the Kuroshio Extension front in May. Sensitivity experiments demonstrate that the mesoscale geostrophic currents basically governed the transport processes in the open ocean after April. In the shelf region, on the other hand, the wind-driven currents facilitate the north-south extension of the radionuclide distribution through the repeated generations of the shelf waves. Influences of tide and river discharges cannot be neglected.

  20. 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

  1. 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.

  2. Radiological assessment: predicting the transport, bioaccumulation, and uptake by man of radionuclides released to the environment

    SciTech Connect

    Not Available

    1984-03-15

    This report reviews the current status of the application of radionuclide transport models from the point of discharge to the environment to the point of intake by man. Models are reviewed that describe the transport of radionuclides through the atmosphere, surface and ground waters, deposition on terrestrial surfaces and in sediments, and acccumulation in food products. Usage factors are considered that determine the intake of radionuclides by humans due to dietary habits, physiological parameters, and living customs. Report includes an in-depth analysis of the data base accompanying these models in order to examine potential uncertainties inherent in the choice of model input parameters. Where available, model validation experimental results are included. References.

  3. 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)

  4. 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.

  5. 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.

  6. Sorption and transport of radionuclides by tumbleweeds from two plastic-lined radioactive waste ponds.

    PubMed

    Warren, R W

    2001-01-01

    Previous research has examined the uptake of radionuclides by tumbleweeds growing in contaminated soils, but none has heretofore examined the sorption of radionuclides to tumbleweeds blowing into radioactively contaminated water. Three tumbleweed species; Russian thistle (Salsola kali), Jim Hill mustard (Sisymbrium altissimum) and summer cypress (Kochia scoparia) blow in, and out of, two plastic-lined radioactive wastewater ponds, constructed in 1993 on the US Department of Energy's Idaho National Engineering and Environmental Laboratory in southeast Idaho. This research quantified radionuclide sorption to tumbleweeds, tumbleweed movement from the ponds, and determined radionuclide transport from the ponds. Average plant/water concentration factors associated with tumbleweeds taken from the ponds ranged from 5 for 152Eu to over 9000 for 54Mn. Based on changes in tumbleweed numbers and average concentrations associated with them, 66.2 MBq were estimated to have been transported from the ponds via tumbleweeds between 18 October 1994 and 8 November 1996. This amounts to about 0.01% of the non-tritium and 0.0002% of the tritium activity released to the ponds through 8 November 1996. A power function best described the radionuclide buildup curve for tumbleweeds submerged in the ponds. Visually marked tumbleweeds traveled from the ponds in the predominant wind direction a maximum of 737 m. Management practices which may reduce the number of tumbleweeds blowing both into and out of contaminated ponds are discussed.

  7. Heat-pipe effect on the transport of gaseous radionuclides released from a nuclear waste container

    SciTech Connect

    Zhou, W.; Chambre, P.L.; Pigford, T.H.; Lee, W.W.L.

    1990-11-01

    When an unsaturated porous medium is subjected to a temperature gradient and the temperature is sufficiently high, vadose water is heated and vaporizes. Vapor flows under its pressure gradient towards colder regions where it condenses. Vaporization and condensation produce a liquid saturation gradient, creating a capillary pressure gradient inside the porous medium. Condensate flows towards the hot end under the influence of a capillary pressure gradient. This is a heat pipe in an unsaturated porous medium. We study analytically the transport of gaseous species released from a spent-fuel waste package, as affected by a time-dependent heat pipe in an unsaturated rock. For parameter values typical of a potential repository in partially saturated fractured tuff at Yucca Mountain, we found that a heat pipe develops shortly after waste is buried, and the heat-pipe`s spatial extent is time-dependent. Water vapor movements produced by the heat pipe can significantly affect the migration of gaseous radionuclides. 12 refs., 6 figs., 1 tab.

  8. 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

  9. 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

  10. 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.

  11. Hydrologic response and radionuclide transport following fire at semiarid sites.

    PubMed

    Johansen, M P; Hakonson, T E; Whicker, F W; Simanton, J R; Stone, J J

    2001-01-01

    Infrequent, high-impact events such as wildfires, droughts, biological shifts, floods, and mechanical disturbances can greatly change land surfaces, including vegetative cover and soil characteristics, which in turn can trigger high rates of hydrologic erosion and associated transport of sediments and sediment-sorbed contaminants. Where persistent soil contamination exists, infrequent mobilization of contaminants may dominate in determining long-term risks to human and ecological receptors. Among these infrequent events, fire stands out as having the capacity to cause large increases in sediment transport. This study measured runoff, sediment yield, and mobility of sediment-sorbed contamination (137Cs) on burned and unburned plots at the Waste Isolation Pilot Plant, New Mexico (WIPP), and the Rocky Flats Environmental Technology Site, Colorado (RFETS). Results showed that 137Cs transport from burned plots was up to 22 times greater than that from unburned plots at WIPP and 4 times greater at RFETS. Associated runoff was up to 12 times greater on burned plots at WIPP and sediment yields up to 6 times greater. Further, 137Cs concentrations in transported sediments were enriched compared with parent soils (expressed as enrichment ratio) by a factor of 2.3 at WIPP, and 1.3 at RFETS. However, enrichment ratios were not significantly different in sediments from burned and unburned plots. Our results provide new data on the effects of fire on the transport of sediment-sorbed contaminants, and demonstrate that rare events such as fire can greatly increase contaminant mobility. PMID:11790008

  12. 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

  13. Spatial moments for colloid-enhanced radionuclide transport in heterogeneous aquifers

    NASA Astrophysics Data System (ADS)

    Severino, Gerardo; Cvetkovic, Vladimir; Coppola, Antonio

    2007-01-01

    We consider colloid facilitated radionuclide transport by steady groundwater flow in a heterogeneous porous formation. Radionuclide binding on colloids and soil-matrix is assumed to be kinetically/equilibrium controlled. All reactive parameters are regarded as uniform, whereas the hydraulic log-conductivity is modelled as a stationary random space function (RSF). Colloid-enhanced radionuclide transport is studied by means of spatial moments pertaining to both the dissolved and colloid-bounded concentration. The general expressions of spatial moments for a colloid-bounded plume are presented for the first time, and are discussed in order to show the combined impact of sorption processes as well as aquifer heterogeneity upon the plume migration. For the general case, spatial moments are defined by the aid of two characteristic reaction functions which cannot be expressed analytically. By adopting the approximation for the longitudinal fluid trajectory covariance valid for a flow parallel to the formation bedding suggested by Dagan and Cvetkovic [Dagan G, Cvetkovic V. Spatial Moments of Kinetically Sorbing Plume in a Heterogeneous Aquifers. Water Resour Res 1993;29:4053], we obtain closed form solutions. For illustrative purposes, we consider the case when sorption/desorption between solution and moving colloids is a linear non-equilibrium process, whereas sorption onto the soil-matrix is a linear equilibrium process. Based on the flow and transport parameters pertaining to the alluvial aquifer at the Yucca Mountain Site (Nevada), we investigate the potential enhancing role of colloidal particles by comparing radionuclide spatial moments with and without colloids, and mainly investigate the sensitivity to the reverse rate parameter. The most potentially significant effects are obtained when radionuclide attachment to colloidal particles is irreversible. The simplicity of our results makes them suitable for quick assessments of the potential impact of colloids on

  14. 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.

  15. 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.

  16. 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. PMID:24657852

  17. 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.

  18. 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.

  19. 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.

  20. Assessment of hydrologic transport of radionuclides from the Rulison Underground Nuclear Test Site, Colorado

    SciTech Connect

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

    1996-09-01

    The U.S. Department of Energy (DOE) is operating an environmental restoration program to characterize, remediate, and close non-Nevada Test Site locations that were used for nuclear testing. Evaluation of radionuclide transport by groundwater from these sites is an important part of the preliminary risk analysis. These evaluations are undertaken to allow prioritization of the test areas in terms of risk, provide a quantitative basis for discussions with regulators and the public about future work at the sites, and provide a framework for assessing data needs to be filled by site characterization. The Rulison site in west-central Colorado was the location of an underground detonation of a 40-kiloton nuclear device in 1969. The test took place 2,568 m below ground surface in the Mesaverde Formation. Though located below the regional water table, none of the bedrock formations at the site yielded water during hydraulic tests, indicating extremely low permeability conditions. The scenario evaluated was the migration of radionuclides from the blast-created cavity through the Mesaverde 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. The transport calculations are most sensitive to changes in the mean groundwater velocity and the correlation scale of hydraulic conductivity, with transport of strontium and cesium also sensitive to the sorption coefficient.

  1. 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.

  2. Radionuclides deposition and fine sediment transport in a forested watershed, central Japan

    NASA Astrophysics Data System (ADS)

    Nam, S.; Gomi, T.; Kato, H.; Tesfaye, T.; Onda, Y.

    2011-12-01

    We investigated radionuclides deposition and fine sediment transport in a 13 ha headwater watershed, Tochigi prefecture, located in 98.94 km north of Tokyo. The study site was within Karasawa experimental forest, Tokyo University of Agriculture and Technology. We conducted fingerprinting approach, based on the activities of fallout radionuclides, including caesium-134 (Cs-134) caesium-137 (Cs-137) and excess lead-210 (Pb-210ex). For indentifying specific sources of fine sediment, we sampled tree, soil on forested floor, soil on logging road surface, stream bed and stream banks. We investigated the radionuclides (i.e., as Cs-134, Cs-137 and Pb-210ex) deposition on tree after accident of nuclear power plants on March 11, 2011. We sampled fruits, leaves, branches, stems, barks on Japanese cedar (Sugi) and Japanese cypress (Hinoki). To analyze the samples, gammaray spectrometry was performed at a laboratory at the University of Tsukuba (Tsukuba City, Japan) using n-type coaxial low-energy HPGe gamma detectors (EGC-200-R and EGC25-195-R of EURYSIS Co., Lingolsheim, France) coupled with a multichannel analyzer. We also collected soil samples under the forest canopy in various soil depths from 2, 5, 10, 20, 30 cm along transect of hillslopes. Samples at forest road were collected road segments crossing on the middle section of monitoring watersheds. Fine sediment transport in the streams were collected at the outlet of 13 ha watersheds using integrated suspended sediment samplers. This study indicates the some portion of radio nuclide potentially remained on the tree surface. Part of the deposited radionuclides attached to soil particles and transported to the streams. Most of the fine sediment can be transported on road surface and/or near stream side (riparian zones).

  3. 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.

  4. 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.

  5. 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

  6. 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

  7. A simplified model for calculating atmospheric radionuclide transport and early health effects from nuclear reactor accidents

    SciTech Connect

    Madni, I.K.; Cazzoli, E.G.; Khatib-Rahbar, M.

    1995-11-01

    During certain hypothetical severe accidents in a nuclear power plant, radionuclides could be released to the environment as a plume. Prediction of the atmospheric dispersion and transport of these radionuclides is important for assessment of the risk to the public from such accidents. A simplified PC-based model was developed that predicts time-integrated air concentration of each radionuclide at any location from release as a function of time integrated source strength using the Gaussian plume model. The solution procedure involves direct analytic integration of air concentration equations over time and position, using simplified meteorology. The formulation allows for dry and wet deposition, radioactive decay and daughter buildup, reactor building wake effects, the inversion lid effect, plume rise due to buoyancy or momentum, release duration, and grass height. Based on air and ground concentrations of the radionuclides, the early dose to an individual is calculated via cloudshine, groundshine, and inhalation. The model also calculates early health effects based on the doses. This paper presents aspects of the model that would be of interest to the prediction of environmental flows and their public consequences.

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

    NASA Astrophysics Data System (ADS)

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

    2016-01-01

    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 work, 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.

  9. 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. PMID:11601529

  10. Size dispersion and colloid mediated radionuclide transport in a synthetic porous media.

    PubMed

    Delos, A; Walther, C; Schäfer, T; Büchner, S

    2008-08-01

    Size dispersion effects during the migration of natural submicron bentonite colloids (<200 nm) through a ceramic column are observed for the first time by laser-induced breakdown detection (LIBD) at ppm (parts per million) mass concentration. Larger size fractions ( approximately 200 nm) arrive prior to smaller size fractions (<100 nm) at the column outlet in agreement with model predictions and earlier findings with carboxylated polystyrene spheres. By addition of trace amounts of americium(III) and plutonium(IV), colloid mediated transport of these radionuclides is studied. The peak arrival times of Pu-244 and Am-241, as measured by ICP-MS, match the bentonite colloid breakthrough and occur significantly prior to the conservative tracer (HTO) indicating the colloid-borne migration of tri- and tetravalent radionuclides. PMID:18514680

  11. Assessment of hydrologic transport of radionuclides from the Gnome underground nuclear test site, New Mexico

    SciTech Connect

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

    1996-09-01

    The U.S. Department of Energy (DOE) is operating an environmental restoration program to characterize, remediate, and close non-Nevada Test Site locations that were used for nuclear testing. Evaluation of radionuclide transport by groundwater from these sites is an important part of the preliminary site risk analysis. These evaluations are undertaken to allow prioritization of the test areas in terms of risk, provide a quantitative basis for discussions with regulators and the public about future work at the sites, and provide a framework for assessing data needs to be filled by site characterization. The Gnome site in southeastern New Mexico was the location of an underground detonation of a 3.5-kiloton nuclear device in 1961, and a hydrologic tracer test using radionuclides in 1963. The tracer test involved the injection of tritium, {sup 90}Sr, and {sup 137}Cs directly into the Culebra Dolomite, a nine to ten-meter-thick aquifer located approximately 150 in below land surface. The Gnome nuclear test was carried out in the Salado Formation, a thick salt deposit located 200 in below the Culebra. Because salt behaves plastically, the cavity created by the explosion is expected to close, and although there is no evidence that migration has actually occurred, it is assumed that radionuclides from the cavity are released into the overlying Culebra Dolomite during this closure process. 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 may be present in concentrations exceeding drinking water regulations outside the drilling exclusion boundary established by DOE. Calculated mean tritium concentrations peak at values exceeding the U.S. Environmental Protection Agency drinking water standard of 20,000 pCi/L at distances of up to almost eight kilometers west of the nuclear test.

  12. 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

  13. Mass transfer and transport of radionuclides through backfill in a geologic nuclear waster repository

    SciTech Connect

    Kang, Chulhyung.

    1989-01-01

    Analytical models for the mass transfer and transport of radionuclides through waste package backfill material are developed and their numerical illustrations are demonstrated. These models can aid in the performance assessment of the waste package in nuclear waste repositories. The following analyses are considered to study the performance of the backfill barrier in a geologic nuclear waste repository. (1) The analysis for time and space dependent mass transfer and mass transport of a radioactive decay chain for a congruent release with the matrix species is studied. Non-recursive analytical solutions are derived for a semi-infinite medium and a finite medium. The theory is illustrated with the important decay chain {sup 234}U {yields} {sup 230}Th {yields} {sup 226}Ra. (2) The time and space dependent mass transport for high solubility nuclides, such as iodine or cesium, is analyzed. The approximate solution that is valid for all times is developed, and validated by comparison with an asymptotic solution and the solution obtained by the numerical inversion of a Laplace transform covering the entire time span. From this model one can determine the thickness of the backfill to satisfy a prescribed release rate limit for high soluble radionuclides. (3) The analysis of the transient radionuclide migration through the backfill into a fracture intersecting the waste form is developed. The nuclides are advected by water flowing in the fracture. The numerical illustrations show that the species transport for the short half-life nuclide can be stopped effectively within the backfill, but the backfill can no longer retard the migration for stable nuclides or long half-life nuclides after some initial time period. (4) The steady state mass transfer from a cylindrical waste form with flow through the backfill layer is examined.

  14. CASCADER: An m-chain gas-phase radionuclide transport and fate model. Volume 1, Basic physics and mathematics

    SciTech Connect

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

    1992-06-01

    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 as they are advected and/or dispersed. Furthermore, parent and daughter radionuclides may decay as they are transported in the soil. CASCADER is a gas-phase, one space dimensional transport and fate model for an m-chain of radionuclides in very dry soil. This model contains barometric pressure-induced advection and diffusion together with linear irreversible and linear reversible sorption for each radionuclide. The advocation velocity is derived from an embedded air-pumping submodel. The airpumping submodel is based on an assumption of isothermal conditions and is barometric pressure driven. CASCADER allows the concentration of source radionuclides to decay via the classical Bateman chain of simple, first-order kinetic processes. The transported radionuclides also decay via first-order processes while in the soil. A mass conserving, flux-type inlet and exit set of boundary conditions is used. The user must supply the initial distribution for the parent radionuclide in the soil. The initial daughter distribution is found using equilibrium rules. The model is user friendly as it uses a prompt-driven, free-form input. The code is ANSI standard Fortran 77.

  15. 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

  16. Small agricultural impoundments affect pollutant transport

    NASA Astrophysics Data System (ADS)

    Balcerak, Ernie

    2013-03-01

    Reservoirs created by dams intercept runoff from upslope areas and thus are often sinks for fertilizers and other pollutants that would otherwise flow downstream. Most studies of solute transport through impoundments have focused on large, long-lived systems. However, small impoundments, such as those created for irrigation or livestock watering, are common in agricultural regions, and their total global surface area is comparable to that of large reservoirs. As these small systems mature, the impoundments fill with sediment, creating ecosystems with wetland-like characteristics. Because dams that create these small impoundments are more likely to be degraded, poorly maintained, or removed by their owners, it is important to understand how changes in such systems may affect pollutant transport.

  17. 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.

  18. 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).

  19. 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.

  20. 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.

  1. Radionuclides as indicators of sediment transport in agricultural watersheds that drain to Lake Erie.

    PubMed

    Matisoff, Gerald; Bonniwell, Everett C; Whiting, Peter J

    2002-01-01

    An issue in evaluating the success of agricultural management practices is the speed that eroded particles make their way through the downstream waters. In this study at Old Woman Creek (OWC) and Rock Creek (RC), two largely agricultural watersheds in Ohio, the flux of sediment and radionuclides (7Be, 210Pb, and 137Cs) in thunderstorm runoff was examined to better understand transport of eroded agricultural soils. The hydrograph in an agricultural area under no-till was similar in timing, but of lesser magnitude, than the hydrograph from a similar-sized area under conventional tillage. The activities of 210Pb and 7Be are linearly correlated and are higher in suspended sediments derived from no-till subbasins than those derived from conventionally tilled subbasins. A suspended sediment plume, identified by its unique radionuclide signature, was traced through 17 km of OWC stream channel in approximately 13.4 h (0.35 m/s). The downstream exponential decrease of 7Be activities in suspended sediments 3 to 12 h after passage of the sediment plume was used to estimate transport distances of suspended sediment from 2 to 17 km, respectively. Transport distances of suspended sediments were also calculated from wave kinematics and indicate that at OWC suspended sediment transport distances were longer in streams draining areas of no-till (19-26 km) than in the streams draining areas of conventional tillage (6-15 km). Suspended sediments travel 7 to 22 km at RC. The transport distances are long relative to the lengths of the stream channel and indicate that erosion control methods implemented in the watershed should be reflected quickly in downstream waters.

  2. Radionuclides as indicators of sediment transport in agricultural watersheds that drain to Lake Erie.

    PubMed

    Matisoff, Gerald; Bonniwell, Everett C; Whiting, Peter J

    2002-01-01

    An issue in evaluating the success of agricultural management practices is the speed that eroded particles make their way through the downstream waters. In this study at Old Woman Creek (OWC) and Rock Creek (RC), two largely agricultural watersheds in Ohio, the flux of sediment and radionuclides (7Be, 210Pb, and 137Cs) in thunderstorm runoff was examined to better understand transport of eroded agricultural soils. The hydrograph in an agricultural area under no-till was similar in timing, but of lesser magnitude, than the hydrograph from a similar-sized area under conventional tillage. The activities of 210Pb and 7Be are linearly correlated and are higher in suspended sediments derived from no-till subbasins than those derived from conventionally tilled subbasins. A suspended sediment plume, identified by its unique radionuclide signature, was traced through 17 km of OWC stream channel in approximately 13.4 h (0.35 m/s). The downstream exponential decrease of 7Be activities in suspended sediments 3 to 12 h after passage of the sediment plume was used to estimate transport distances of suspended sediment from 2 to 17 km, respectively. Transport distances of suspended sediments were also calculated from wave kinematics and indicate that at OWC suspended sediment transport distances were longer in streams draining areas of no-till (19-26 km) than in the streams draining areas of conventional tillage (6-15 km). Suspended sediments travel 7 to 22 km at RC. The transport distances are long relative to the lengths of the stream channel and indicate that erosion control methods implemented in the watershed should be reflected quickly in downstream waters. PMID:11837446

  3. Evaluation of Subsurface Radionuclide Transport at Commercial Nuclear Power Production Facilities

    NASA Astrophysics Data System (ADS)

    Rasmussen, T. C.; Bollinger, J. S.

    2006-05-01

    An American Nuclear Society (ANS) working group was recently established to revise ANSI/ANS-2.17, a standard for evaluating radionuclide transport in ground water at commercial nuclear power production (NPP) facilities. The working group consists of technical experts from the nuclear industry, Federal and State regulatory agencies, universities, DOE National Laboratories, and hydrogeologic consulting firms. ANS 2.17 was originally adopted in 1980, reaffirmed in 1990, but subsequently withdrawn in 2000 due to a lapse in the decadal concurrence process. The working group charge is to re-visit the lapsed standard, review the state-of-the-science and -practice, and develop a performance-based standard that provides guidelines for demonstrating the ability to detect, characterize, diagnose, quantify, and effectively mitigate accidental and routine subsurface releases of radionuclides from NPP facilities. The resulting consensus standard focuses on subsurface site characterization, monitoring, and modeling issues at NPP sites that will guide the siting and evaluation of radionuclide transport at both existing and proposed new NPP facilities. This presentation provides the technical background for developing the standard along with a description of its current status. Performance Assessment is the proposed framework for designing characterization, monitoring, and modeling programs that quantitatively evaluate release scenarios. Geographic Information Systems (GIS) are proposed for the archival and retrieval of spatially-explicit data, and will include real-time designators. New monitoring technologies are identified that may aid in the detection and characterization of releases. Remediation activities in response to detected releases should reflect, in part, the expected risk as defined using response thresholds. The presenters are actively soliciting technical documents and field application experiences which may contribute to the standard's technical bases and

  4. 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

  5. Modelling radionuclide transport in large fractured-media systems: the example of Forsmark, Sweden

    NASA Astrophysics Data System (ADS)

    Schwartz, Michael O.

    2012-06-01

    The planned high-level nuclear waste repository at Forsmark, Sweden, will accommodate 6,824 containers with a total of 13,920 tonnes of uranium in burnt fuel at approximately 400 m depth in a fractured-granite aquifer. The transport of radionuclides, which may be released from the disposed waste, is simulated with the TOUGHREACT code for a three-dimensional model with 305,571 elements. The model performs coupled flow-transport simulations. It aims to achieve more realistic simulations of contaminant transport than the commonly used decoupled procedure consisting of three-dimensional flow and one-dimensional transport simulations. The model has a relatively small problem size because it is designed as a double-porosity model (one matrix continuum) that is the parameterised equivalent of a much larger multiple-interacting continua (MINC) model, i.e. a model with a finely discretised matrix (several matrix continua). The parameterisation is performed with two-dimensional models. Only one or two variables among three variables (diffusive transport distance between fracture and matrix, retardation factor and effective diffusivity) have to be parameterised. The results obtained with the parameterised three-dimensional model are very close to those that can be obtained with a much larger MINC model but may be quite different from those that can be obtained with the conventional decoupled procedure.

  6. 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

  7. Use of Transportable Radiation Detection Instruments to Assess Internal Contamination From Intakes of Radionuclides Part I: Field Tests and Monte Carlo Simulations.

    PubMed

    Anigstein, Robert; Erdman, Michael C; Ansari, Armin

    2016-06-01

    The detonation of a radiological dispersion device or other radiological incidents could result in the dispersion of radioactive materials and intakes of radionuclides by affected individuals. Transportable radiation monitoring instruments could be used to measure photon radiation from radionuclides in the body for triaging individuals and assigning priorities to their bioassay samples for further assessments. Computer simulations and experimental measurements are required for these instruments to be used for assessing intakes of radionuclides. Count rates from calibrated sources of Co, Cs, and Am were measured on three instruments: a survey meter containing a 2.54 × 2.54-cm NaI(Tl) crystal, a thyroid probe using a 5.08 × 5.08-cm NaI(Tl) crystal, and a portal monitor incorporating two 3.81 × 7.62 × 182.9-cm polyvinyltoluene plastic scintillators. Computer models of the instruments and of the calibration sources were constructed, using engineering drawings and other data provided by the manufacturers. Count rates on the instruments were simulated using the Monte Carlo radiation transport code MCNPX. The computer simulations were within 16% of the measured count rates for all 20 measurements without using empirical radionuclide-dependent scaling factors, as reported by others. The weighted root-mean-square deviations (differences between measured and simulated count rates, added in quadrature and weighted by the variance of the difference) were 10.9% for the survey meter, 4.2% for the thyroid probe, and 0.9% for the portal monitor. These results validate earlier MCNPX models of these instruments that were used to develop calibration factors that enable these instruments to be used for assessing intakes and committed doses from several gamma-emitting radionuclides. PMID:27115229

  8. Biotic transport of radionuclides from a low-level radioactive waste site.

    PubMed

    Kennedy, W E; Cadwell, L L; McKenzie, D H

    1985-07-01

    In the United States, concern for human exposures to radioactivity associated with the disposal of low-level radioactive waste has resulted in a series of regulatory guides, environmental assessments, management practices, and modeling tools. A large number of radionuclide transport processes and mechanisms that may contribute to human exposure have been modeled, using computer programs to make the required calculations. The objective of our work was to evaluate the relevance of potential biological transport processes in the assessment of potential impacts at low-level waste (LLW) disposal sites. As part of this effort, we developed an order-of-magnitude estimate for potential dose to man resulting from biological transport by burrowing animals and by plant translocation at a reference low-level waste site in the arid west. We also made comparative dose-to-man estimates for a more commonly considered human intrusion exposure scenario. Parameter values for defining a reference arid LLW disposal site and biotic transport processes are based on data reported in current literature. Estimates of waste volumes for the western United States are based on information described by the U.S. Nuclear Regulatory Commission in the Draft Environmental Impact Statement in support of 10 CFR Part 61. Our estimates of the dose-to-man resulting from biotic transport are of the same order of magnitude as those resulting from a more commonly evaluated human intrusion scenario. The previously assumed lack of potential importance of biotic transport at LLW sites in earlier assessment studies is not confirmed by our findings. Our results indicate that long-term biological transport processes have the potential to influence LLW site performance, and should be carefully evaluated as part of the impact assessment process. PMID:4008258

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

    DOE PAGES

    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 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

  10. Properties of two tropical soils in relation to the transport of radionuclides in the rhizosphere.

    PubMed

    Itakura, Takashi; Kuo, Eugenia Y; Twining, John R

    2004-01-01

    The uptake of radionuclides by commercial crops is being studied at two sites, Blain and Tippera, in a research farm in the Northern Territory, Australia. Studies have been performed to characterise the properties of the two soils, particularly the hydraulic properties that are considered to significantly influence the transport and plant uptake of these radionuclides in the soils The Blain soil, a sandy loam, has been categorised as SM according to the Unified Soil Classification System. Quartz is the dominant mineral for the Blain soil. The Tippera soil, a kaolinitic clayey loam has been categorised as CL. Chemical analysis results were consistent with these findings. The saturated hydraulic conductivity values were of the order of 10(-4) cm/s for the Blain soil. These values were greater by 3-4 orders of magnitude than those for the Tippera soils. The results obtained from the hydraulic property measurements were used to estimate the unsaturated hydraulic properties. A bimodal description based on van Genuchten-type partial saturation functions was used for the estimation. The estimation was qualitatively consistent with the soil types. PMID:15245852

  11. 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

  12. 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

  13. 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

  14. 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

  15. Development and testing of radionuclide transport models for fractured rock: examples from the Nagra/JNC Radionuclide Migration Programme in the Grimsel Test Site, Switzerland.

    PubMed

    Smith, P A; Alexander, W R; Kickmaier, W; Ota, K; Frieg, B; McKinley, I G

    2001-02-01

    The joint Swiss National Co-operative for the Disposal of Radioactive Waste (Nagra)/Japan Nuclear Cycle Development Institute (JNC) Radionuclide Migration Programme has now been on-going for over a decade in Nagra's Grimsel Test Site (GTS). The main aim of the programme has been the direct testing of radionuclide transport models in as realistic manner as possible. Although it will never be possible to fully test these models due to the large time and distance scales involved, tests of the model assumptions in scaled down but otherwise realistic conditions will contribute to developing confidence in the predictive power of the models. In this paper, the Nagra/JNC approach is highlighted with examples from a large programme of field, laboratory and natural analogue studies based around the GTS. The successes and failures are discussed as in the general approach to the thorough testing of predictive transport codes which will be used in repository performance assessment (PA). Some of the work is still on-going and this represents the first presentation of a unique set of results and conclusions.

  16. 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

  17. Radionuclide release and transport from nuclear underground tests performed at Mururoa and Fangataufa--predictions under uncertainty.

    PubMed

    Pfingsten, W; Hadermann, J; Perrochet, P

    2001-02-01

    In the context of a study by the International Geomechanical Commission (IGC) and the International Atomic Energy Agency (IAEA) on the effects of nuclear tests at the atolls of Mururoa and Fangataufa, release to the biosphere is estimated for 35 radionuclides originating from 147 nuclear underground tests. Based on a qualitatively characterised hydrogeological situation of atolls and relatively scarce site-specific data, a model chain was developed to conservatively estimate the radionuclide fluxes via groundwater, from their sources, the explosion cavities, towards the biosphere, the ocean or lagoon. Finite element hydro-thermal modelling was used to describe water flow. Parameters were calibrated by a very few measured pre-test temperature profiles in bore holes. The impact of the tests on groundwater flow and mechanical impact on rock was considered. Estimates were made to quantify spatial extensions and temporal evolution of impact by using measurements on refilling rate of the cavities. Tests were categorised according to their specific yield and location although detailed data were missing. A base case parameter set was defined for the hydraulic conditions and for the initial radionuclide inventory of individual tests. Models were used to describe the concentration of radionuclides in the cavities as a function of time. Radionuclide transport from the cavities to the biosphere was represented by two different approaches: a double porosity model for the fractured volcanic rock and a single porosity model for the overlaying, highly porous carbonates. Results consist of conservative estimates on radionuclide release into the environment, or concentration in the lagoon or ocean water. Their sensitivity was investigated using different models and parameters. A few measured data (concentrations in a few cavities, in the deep carbonates and in the lagoons for selected radionuclides, such as 3H, 14C, 36Cl, 90Sr, 129I, 137Cs239 240Pu and 241Am) were available for a

  18. Coupled Hydrological and Geochemical Processes Governing the Fate and Transport of Radionuclides and Toxic Metals in the Hanford Vadose Zone

    SciTech Connect

    Mayes, M.A.; Jardine, P.M.; Fendorf, S.E.; Pace, M.N.; Yin, X.; Mehlhorn, T.L.; Zachara, J.M.

    2003-03-27

    At the D.O.E. Hanford Reservation, accelerated migration of radionuclides has been observed in the vadose zone underlying the tank farms. Our goal is to provide an improved understanding and predictive capability of the coupled hydrogeochemical mechanisms responsible for observed migration. Our approach is to perform a suite of experiments ranging from novel surface interrogation techniques (e.g., XAS) to miscible displacement experiments on disturbed and undisturbed sediments from the Hanford, Plio-Pleistocene and Ringold formations. Results indicate during unsaturated conditions hydrologic processes governing transport are a strong function of sediment layering in the Hanford and Ringold formations. The transport of radionuclides and toxic metals (U, Cr(VI), Cs, Sr and Co) is influenced by reactive geochemical nonequilibrium, sedimentary mineralogy and solution chemistry. This research will provide new insights into how physical and mineralogical heterogeneities (e.g. stratification, pore regime connectivity, mineral composition along flowpaths) influence contaminant retardation and degree of geochemical nonequilibrium during transport.

  19. 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

  20. 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.

  1. Evaluation of conceptual, mathematical and physical-and-chemical models for describing subsurface radionuclide transport at the Lake Karachai Waste Disposal Site

    SciTech Connect

    Rumynin, V.G.; Mironenko, V.A.; Sindalovsky, L.N.; Boronina, A.V.; Konosavsky, P.K.; Pozdniakov, S.P.

    1998-06-01

    The goal of this work was to develop the methodology and to improve understanding of subsurface radionuclide transport for application to the Lake Karachai Site and to identify the influence of the processes and interactions involved into transport and fate of the radionuclides. The report is focused on two sets of problems, which have to do both with, hydrodynamic and hydrogeochemical aspects of the contaminant transport.

  2. Effect of transport-pathway simplifications on projected releases of radionuclides from a nuclear waste repository (Sweden)

    NASA Astrophysics Data System (ADS)

    Selroos, Jan-Olof; Painter, Scott L.

    2012-12-01

    The Swedish Nuclear Fuel and Waste Management Company has recently submitted an application for a license to construct a final repository for spent nuclear fuel, at approximately 500 m depth in crystalline bedrock. Migration pathways through the geosphere barrier are geometrically complex, with segments in fractured rock, deformation zones, backfilled tunnels, and near-surface soils. Several simplifications of these complex migration pathways were used in the assessments of repository performance that supported the license application. Specifically, in the geosphere transport calculations, radionuclide transport in soils and tunnels was neglected, and deformation zones were assumed to have transport characteristics of fractured rock. The effects of these simplifications on the projected performance of the geosphere barrier system are addressed. Geosphere performance is shown to be sensitive to how transport characteristics of deformation zones are conceptualized and incorporated into the model. Incorporation of advective groundwater travel time within backfilled tunnels reduces radiological dose from non-sorbing radionuclides such as I-129, while sorption in near-surface soils reduces radiological doses from sorbing radionuclides such as Ra-226. These results help quantify the degree to which geosphere performance was pessimistically assessed, and provide some guidance on how future studies to reduce uncertainty in geosphere performance may be focused.

  3. A geostatistical modeling study of the effect of heterogeneity on radionuclide transport in the unsaturated zone, Yucca Mountain.

    PubMed

    Viswanathan, Hari S; Robinson, Bruce A; Gable, Carl W; Carey, James W

    2003-01-01

    Retardation of certain radionuclides due to sorption to zeolitic minerals is considered one of the major barriers to contaminant transport in the unsaturated zone of Yucca Mountain. However, zeolitically altered areas are lower in permeability than unaltered regions, which raises the possibility that contaminants might bypass the sorptive zeolites. The relationship between hydrologic and chemical properties must be understood to predict the transport of radionuclides through zeolitically altered areas. In this study, we incorporate mineralogical information into an unsaturated zone transport model using geostatistical techniques to correlate zeolitic abundance to hydrologic and chemical properties. Geostatistical methods are used to develop variograms, kriging maps, and conditional simulations of zeolitic abundance. We then investigate, using flow and transport modeling on a heterogeneous field, the relationship between percent zeolitic alteration, permeability changes due to alteration, sorption due to alteration, and their overall effect on radionuclide transport. We compare these geostatistical simulations to a simplified threshold method in which each spatial location in the model is assigned either zeolitic or vitric properties based on the zeolitic abundance at that location. A key conclusion is that retardation due to sorption predicted by using the continuous distribution is larger than the retardation predicted by the threshold method. The reason for larger retardation when using the continuous distribution is a small but significant sorption at locations with low zeolitic abundance. If, for practical reasons, models with homogeneous properties within each layer are used, we recommend setting nonzero K(d)s in the vitric tuffs to mimic the more rigorous continuous distribution simulations. Regions with high zeolitic abundance may not be as effective in retarding radionuclides such as Neptunium since these rocks are lower in permeability and contaminants can

  4. 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.

  5. 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.

  6. Sources and transport of anthropogenic radionuclides in the Ob River system, Siberia

    NASA Astrophysics Data System (ADS)

    Cochran, J. Kirk; Moran, S. Bradley; Fisher, Nicholas S.; Beasley, Thomas M.; Kelley, James M.

    2000-06-01

    The potential sources of anthropogenic radionuclides to the Ob River system of western Siberia include global stratospheric fallout, tropospheric fallout from atomic weapons tests and releases from production and reprocessing facilities. Samples of water, suspended and bottom sediments collected in 1994 and 1995 have been used to characterize the sources and transport of 137Cs, Pu isotopes, 237Np and 129I through the system. For the radionuclides that associate with particles, isotope ratios provide clues to their sources, providing any geochemical fractionation can be taken into account. Activity ratios of 239,240Pu/ 137Cs in suspended sediments are lower than the global fallout ratio in the Irtysh River before its confluence with the Ob, comparable to fallout in the central reach of the Ob, and greater than the fallout values in the lower Ob and in the Taz River. This pattern mirrors the downriver decrease in dissolved organic carbon (DOC) concentrations. Laboratory adsorption experiments with Ob River sediment and water show that Kd values for Am (and presumably other actinides) are depressed by two orders of magnitude in the presence of Ob DOC concentrations, relative to values measured in DOC-free Ob water. Iodine and cesium Kd values show little or no (less than a factor of 2) dependence on DOC. Mixing plots using plutonium isotope ratios (atom ratios) show that Pu in suspended sediments of the Ob is a mixture of stratospheric global fallout at northern latitudes, tropospheric fallout from the former Soviet Union test site at Semipalatinsk and reprocessing of spent fuel at Tomsk-7. Plutonium from Semipalatinsk is evident in the Irtysh River above its confluence with the Tobal. Suspended sediment samples taken in the Ob above its confluence with the Irtysh indicate the presence of Pu derived from the Tomsk-7 reprocessing facilities. A mixing plot constructed using 237Np/ 239Pu vs. 240Pu/ 239Pu shows similar mixtures of stratospheric and tropospheric fallout

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. Sediment and radionuclide transport in rivers. Summary report, field sampling program for Cattaraugus and Buttermilk Creeks, New York

    SciTech Connect

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

    1982-11-01

    A three-phase field sampling program was conducted on the Buttermilk-Cattaraugus Creek system 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. Phase 1 of the sampling program was conducted during November and December 1977; Phase 2 during September 1978; and Phase 3 during April 1979. Bed sediment, suspended sediment, and water samples were collected over a 45-mile reach of the creek system. Bed sediment samples were also collected at the mouth of Cattaraugus Creek in Lake Erie. A fourth sampling trip was conducted during May 1980 to obtain supplementary channel geometry data and flood plain sediment samples. 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.

  12. Emission, transport, deposition, and re-suspension of radionuclides from Fukushima Dai-ichi Nuclear Power Plant in the atmosphere - Overview of 2-year investigations in Japan

    NASA Astrophysics Data System (ADS)

    Kita, Kazuyuki; Igarashi, Yasuhiro; Yoshida, Naohiro; Nakajima, Teruyuki

    2013-04-01

    Following a huge earthquake and tsunami in Eastern Japan on 11 March, 2011, the accident in Fukushima Dai-ichi Nuclear Power Plant (FDNPP) occurred to emit a large amount of artificial radionuclides to the environment. Soon after the FDNPP accident, many Japanese researchers, as well as researchers in other countries, started monitoring radionuclides in various environmental fields and/or model calculations to understand extent and magnitude of radioactive pollution. In this presentation, we overview these activities for the atmospheric radionuclides in Japan as followings: 1. Investigations to evaluate radionuclide emissions by explosions at FNDPP in March 2011 and to estimate the respiration dose of the radiation at this stage. 2. Investigations to evaluate atmospheric transport and deposition processes of atmospheric radionuclide to determine the extent of radionuclide pollution. -- Based on results of the regular and urgent monitoring results, as well as the mapping of the distribution of radionuclide s accumulated by the deposition to the ground, restoration of their time-dependent emission rates has been tried, and processes determining atmospheric concentration and deposition to the ground have been investigated by using the model calculations. 3. Monitoring of the atmospheric concentrations of radionuclide after the initial, surge phase of FNDPP accident. 4. Investigations to evaluate re-suspension of radionuclide from the ground, including the soil and the vegetation. -- Intensive monitoring of the atmospheric concentrations and deposition amount of radionuclide after the initial, surge phase of the accident enable us to evaluate emission history from FNDPP, atmospheric transport and deposition processes, chemical and physical characteristics of atmospheric radionuclide especially of radio cesium, and re-suspension processes which has become dominant process to supply radio cesium to the atmosphere recently.

  13. 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.

  14. 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

  15. 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

    2006-04-05

    Various U. S. Department of Energy (DOE) low and medium-level radioactive waste sites contain mixtures of heavy metals, radionuclides and assorted organic materials. Over time, water infiltrates the wastes, and releases metals and radionuclides causing transport into the surrounding environment. We propose that fermentative microorganisms are active in these sites and may control metal and radionuclide migration from source zones (Figure 1). The following overarching hypothesis will drive our research: 'Metals and radionuclides 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 compounds can increase metal and radionuclide mobility by chelation (i.e., certain organic acids) or decrease mobility by stimulating respiratory metal reducing microorganisms.' The objective of our research is to determine the effect of carbon and energy flow through simulated waste environments on metal and radionuclide migration from waste pits and trenches across the DOE complex. Metals and radionuclides can be mobilized by infiltration of water into waste storage sites. Cellulolytic and non-cellulolytic fermentative microorganisms have been chosen as the focus of this research because their activity is a critical first step that we hypothesize will control subsequent fate and transport in contaminated natural systems. 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

  16. Modelling radionuclide transport in highly heterogeneous media and under variable hydrochemical conditions using a "dynamic Kd" approach

    NASA Astrophysics Data System (ADS)

    Trinchero, Paolo; Painter, Scott; Ebrahimi, Hedieh; Koskinen, Lasse; Molinero, jorge; Selroos, Jan-Olof

    2015-04-01

    Due to the high heterogeneity of fractured media and the ubiquitous lack of a complete site characterization, deterministic simulations of radionuclide transport in fractured rocks are notoriously highly uncertain. This uncertainty is usually addressed using stochastic methods; e.g. the connectivity structure of the medium is described using multiple realizations of Discrete Fracture Networks (DFN), which are then combined to particle tracking simulations. In these formulations, many complex geochemical retention processes are typically lumped into a single parameter: the distribution coefficient (Kd). This approach relies on an important assumption: the Kd values are constant in time. This hypothesis is critical under long-term geochemical changes as it is known that the distribution coefficient depends on the pH, redox conditions and major chemistry of the system. In this work, we present a novel methodology that combines the robustness of stochastic methods with an explicit description of water-solute-rock interaction processes. The reconciliation of all these is achieved by using a dynamic Kd approach. The hydrogeochemical evolution of the site of study is first computed using long-term and large-scale mechanistic reactive transport simulations. The simulated hydrochemical conditions are then used to generate a complete database of Kd values, which represent the hydrochemical conditions in every position and time of the model domain. Then, MARFA (Painter and Mancillas, 2009) is used to carry out Time Domain Random Walk (TDRW) simulations of radionuclide transport. In these simulations, Kd values are dynamically updated using the afore-mentioned database. The results (i.e. radionuclide breakthrough curves) bring the signature of the underlying changes in the background geochemistry.

  17. 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.

  18. Groundwater flow and radionuclide decay-chain transport modelling around a proposed uranium tailings pond in India

    NASA Astrophysics Data System (ADS)

    Elango, L.; Brindha, K.; Kalpana, L.; Sunny, Faby; Nair, R. N.; Murugan, R.

    2012-06-01

    Extensive hydrogeological investigations followed by three-dimensional groundwater flow and contaminant transport modelling were carried out around a proposed uranium tailings pond at Seripalli in Andhra Pradesh, India, to estimate its radiological impact. The hydrogeological parameters and measured groundwater level were used to model the groundwater flow and contaminant transport from the uranium tailings pond using a finite-element-based model. The simulated groundwater level compares reasonably with the observed groundwater level. Subsequently, the transport of long-lived radionuclides such as 238U, 234U, 230Th and 226Ra from the proposed tailings pond was modelled. The ingrowths of progenies were also considered in the modelling. It was observed that these radionuclides move very little from the tailings pond, even at the end of 10,000 y, due to their high distribution coefficients and low groundwater velocities. These concentrations were translated into committed effective dose rates at different distances in the vicinity of the uranium tailings pond. The results indicated that the highest effective dose rate to members of the public along the groundwater flow pathway is 2.5 times lower than the drinking water guideline of 0.1 mSv/y, even after a long time period of 10,000 y.

  19. 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

  20. Efficient Modelling of Radionuclide Transport in Highly Heterogeneous Media and Under Variable Hydrochemical Conditions Using an "Intelligent Kd" Approach

    NASA Astrophysics Data System (ADS)

    Trinchero, P.; Painter, S. L.; Ebrahimi, H.; Koskinen, L.; Molinero, J.; Selroos, J. O.

    2014-12-01

    Due to the high heterogeneity of fractured media and the ubiquitous lack of a complete site characterization, deterministic simulations of radionuclide transport in fractured rocks are notoriously highly uncertain. This epistemic uncertainty is typically addressed using stochastic methods; e.g. the connectivity structure of the medium is described using one or multiple realizations of Discrete Fracture Networks (DFN), which are then combined to Time Domain Random Walk (TDRW) simulations (e.g. Painter and Cvetkovic, 2005). In these formulations, many complex geochemical retention processes are usually lumped into a single parameter: the distribution coefficient (Kd). Although this approach is mathematically robust and numerically efficient, it relies on an important assumption: the Kd value of each radionuclide is constant in time. This assumption could be critical under long-term geochemical changes as it is demonstrated that the distribution coefficient depends on the pH, redox conditions and major chemistry of the system. In this work, we present a novel methodology that combines the robustness of stochastic methods with a sound and explicit description of water-solute-rock interaction processes. The reconciliation of all these is achieved by using an "intelligent Kd" approach. The hydrogeochemical evolution of the site of study is first computed using long-term and large-scale mechanistic reactive transport simulations. The simulated hydrochemical conditions are then used to generate a complete database of Kd values, which represent the hydrochemical conditions in every position and time of the model domain. Then, TDRW simulations, based on one or multiple DFN realizations, are fed with these data and the results (e.g. radionuclide breakthrough curves) implicitly bring the signature of the underlying changes in the background geochemistry.

  1. 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).

  2. Fusion of waveform events and radionuclide detections with the help of atmospheric transport modelling

    NASA Astrophysics Data System (ADS)

    Krysta, Monika; Kushida, Noriyuki; Kotselko, Yuriy; Carter, Jerry

    2016-04-01

    Possibilities of associating information from four pillars constituting CTBT monitoring and verification regime, namely seismic, infrasound, hydracoustic and radionuclide networks, have been explored by the International Data Centre (IDC) of the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) for a long time. Based on a concept of overlying waveform events with the geographical regions constituting possible sources of the detected radionuclides, interactive and non-interactive tools were built in the past. Based on the same concept, a design of a prototype of a Fused Event Bulletin was proposed recently. One of the key design elements of the proposed approach is the ability to access fusion results from either the radionuclide or from the waveform technologies products, which are available on different time scales and through various different automatic and interactive products. To accommodate various time scales a dynamic product evolving while the results of the different technologies are being processed and compiled is envisioned. The product would be available through the Secure Web Portal (SWP). In this presentation we describe implementation of the data fusion functionality in the test framework of the SWP. In addition, we address possible refinements to the already implemented concepts.

  3. An investigation into the upward transport of uranium-series radionuclides in soils and uptake by plants.

    PubMed

    Pérez-Sánchez, D; Thorne, M C

    2014-09-01

    The upward migration of radionuclides in the (238)U decay series in soils and their uptake by plants is of interest in various contexts, including the geological disposal of radioactive waste and the remediation of former sites of uranium mining and milling. In order to investigate the likely patterns of behaviour of (238)U-series radionuclides being transported upward through the soil column, a detailed soil-plant model originally developed for studying the behaviour of (79)Se in soil-plant systems has been adapted to make it applicable to the (238)U series. By undertaking a reference case simulation and a series of sensitivity studies, it has been found that a wide variety of behaviour can be exhibited by radionuclides in the (238)U decay chain in soils, even when the source term is limited to being a constant flux of either (238)U or (226)Ra. Hydrological conditions are a primary factor, both in respect of the overall advective flow deeper in the soil, which controls the rate of upward migration, and in the influence of seasonally changing flow directions closer to the soil surface, which can result in the accumulation of radionuclides at specific depths irrespective of changes in sorption between the oxic and anoxic regions of the soil. However, such changes in sorption can also be significant in controlling the degree of accumulation that occurs. This importance of seasonally varying factors in controlling radionuclide transport in soils even in very long-term simulations is a strong argument against the use of annually averaged parameters in long-term assessment models. With a water table that was simulated to fluctuate seasonally from a substantial depth in soil to the surface soil layer, the timing of such variations in relation to the period of plant growth was found to have a major impact on the degree of uptake of radionuclides by plant roots. In long-term safety assessment studies it has sometimes been the practice to model the transport of (226)Ra in

  4. Assessment of Uncertainty of Radionuclide Transport in the Yucca Mountain Unsaturated Zone: Parametric and Parameter Estimation Uncertainty

    NASA Astrophysics Data System (ADS)

    Pan, F.; Ye, M.; Wu, Y.; Hu, B.; Shirley, C.; Yu, Z.

    2005-12-01

    This study is to assess uncertainty of radionuclide transport in the unsaturated zone at Yucca Mountain. The uncertainty is attributed to parametric uncertainty due to parameter spatial variability and parameter estimation uncertainty when fitting van Genuchten parameters alpha and n based on water retention measurements. The uncertainty assessment is conducted using Monte Carlo simulation and the three-dimensional flow and transport numerical code, TOUGH2, is employed to simulate unsaturated flow and radionuclide transport in the unsaturated zone. Matrix porosity, saturated hydraulic conductivity, sorption coefficient, and van Genuchten alpha and n parameters are treated as statistically homogeneous random variables. Distributions of the first three random parameters are determined based on site measurements. Seven transformations including three transforms from the Johnson system are applied to the measurements and Lilliefors test is used to identify the best transform that renders the transformed data closest to normal distribution. The fitted matrix van Genuchten alpha and n parameters are assumed to follow normal distributions and parameter estimation uncertainty is measured by the covariance matrix obtained from least square analysis. For each model layer, Latin Hypercube Sampling (LHS) method is used to generate 200 realizations random fields, among which matrix porosity is correlated with saturated hydraulic conductivity and van Genuchten alpha and n are correlated also. The correlation between the former two is measured by Spearman rank correlations estimated from site measurements. The Spearman rank correlation of the latter two is calculated from a large number of generated values using MINTAB software based on their estimated means, variances and covariance. 200 Monte Carlo simulations are conducted using the TOUGH2 and convergence of the Monte Carlo results is thoroughly examined. Mean, variances, 5% and 95% percentiles of saturation, capillary

  5. 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).

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

    PubMed

    Wang, Y; Papenguth, H W

    2001-02-01

    Microbial reactions play an important role in regulating pore water chemistry as well as secondary mineral distribution in many subsurface systems and, therefore, may directly impact radionuclide migration in those systems. This paper presents a general modeling approach to couple microbial metabolism, redox chemistry, and radionuclide transport in a subsurface environment. To account for the likely achievement of quasi-steady state biomass accumulations in subsurface environments, a modification to the traditional microbial growth kinetic equation is proposed. The conditions for using biogeochemical models with or without an explicit representation of biomass growth are clarified. Based on the general approach proposed in this paper, the couplings of uranium reactions with biogeochemical processes are incorporated into computer code BIORXNTRN Version 2.0. The code is then used to simulate a subsurface contaminant migration scenario, in which a water flow containing both uranium and a complexing organic ligand is recharged into an oxic carbonate aquifer. The model simulation shows that Mn and Fe oxyhydroxides may vary significantly along a flow path. The simulation also shows that uranium(VI) can be reduced and therefore immobilized in the anoxic zone created by microbial degradation.

  7. Modeling of long range transport pathways for radionuclides to Korea during the Fukushima Dai-ichi nuclear accident and their association with meteorological circulations.

    PubMed

    Lee, Kwan-Hee; Kim, Ki-Hyun; Lee, Jin-Hong; Yun, Ju-Yong; Kim, Cheol-Hee

    2015-10-01

    The Lagrangian FLEXible PARTicle (FLEXPART) dispersion model and National Centers for Environmental Prediction/Global Forecast System (NCEP/GFS) meteorological data were used to simulate the long range transport pathways of three artificial radionuclides: (131)I, (137)Cs, and (133)Xe, coming into Korean Peninsula during the Fukushima Dai-ichi nuclear accident. Using emission rates of these radionuclides estimated from previous studies, three distinctive transport routes of these radionuclides toward the Korean Peninsula for a period from 10 March to 20 April 2011 were exploited by three spatial scales: 1) intercontinental scale - plume released since mid-March 2011 and transported to the North to arrive Korea on 23 March 2011, 2) global (hemispherical) scale - plume traveling over the whole northern hemisphere passing through the Pacific Ocean/Europe to reach the Korean Peninsula with relatively low concentrations in late March 2011 and, 3) regional scale - plume released on early April 2011 arrived at the Korean Peninsula via southwest sea of Japan influenced directly by veering mesoscale wind circulations. Our identification of these transport routes at three different scales of meteorological circulations suggests the feasibility of a multi-scale approach for more accurate prediction of radionuclide transport in the study area. In light of the fact that the observed arrival/duration time of peaks were explained well by the FLEXPART model coupled with NCEP/GFS input data, our approach can be used meaningfully as a decision support model for radiation emergency situations. PMID:26149179

  8. Modeling of long range transport pathways for radionuclides to Korea during the Fukushima Dai-ichi nuclear accident and their association with meteorological circulations.

    PubMed

    Lee, Kwan-Hee; Kim, Ki-Hyun; Lee, Jin-Hong; Yun, Ju-Yong; Kim, Cheol-Hee

    2015-10-01

    The Lagrangian FLEXible PARTicle (FLEXPART) dispersion model and National Centers for Environmental Prediction/Global Forecast System (NCEP/GFS) meteorological data were used to simulate the long range transport pathways of three artificial radionuclides: (131)I, (137)Cs, and (133)Xe, coming into Korean Peninsula during the Fukushima Dai-ichi nuclear accident. Using emission rates of these radionuclides estimated from previous studies, three distinctive transport routes of these radionuclides toward the Korean Peninsula for a period from 10 March to 20 April 2011 were exploited by three spatial scales: 1) intercontinental scale - plume released since mid-March 2011 and transported to the North to arrive Korea on 23 March 2011, 2) global (hemispherical) scale - plume traveling over the whole northern hemisphere passing through the Pacific Ocean/Europe to reach the Korean Peninsula with relatively low concentrations in late March 2011 and, 3) regional scale - plume released on early April 2011 arrived at the Korean Peninsula via southwest sea of Japan influenced directly by veering mesoscale wind circulations. Our identification of these transport routes at three different scales of meteorological circulations suggests the feasibility of a multi-scale approach for more accurate prediction of radionuclide transport in the study area. In light of the fact that the observed arrival/duration time of peaks were explained well by the FLEXPART model coupled with NCEP/GFS input data, our approach can be used meaningfully as a decision support model for radiation emergency situations.

  9. 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

  10. 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.

  11. 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

  12. 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

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Preliminary testing of turbulence and radionuclide transport modeling in deep ocean environment

    SciTech Connect

    Onishi, Y.; Dummuller, D.C.; Trent, D.S.; Washington State Univ., Pullman, WA; Pacific Northwest Lab., Richland, WA )

    1989-03-01

    Pacific Northwest Laboratory (PNL) performed a study for the US Environmental Protection Agency's Office of Radiation Programs to (1) identify candidate models for regional modeling of low-level waste ocean disposal sites in the mid-Atlantic ocean; (2) evaluate mathematical representation of the model's eddy viscosity/dispersion coefficients; and (3) evaluate the adequacy of the k-{epsilon} turbulence model and the feasibility of one of the candidate models, TEMPEST{copyright}/FLESCOT{copyright}, to deep-ocean applications on a preliminary basis. PNL identified the TEMPEST{copyright}/FLESCOT{copyright}, FLOWER, Blumberg's, and RMA 10 models as appropriate candidates for the regional radionuclide modeling. Among these models, TEMPEST/FLESCOT is currently the only model that solves distributions of flow, turbulence (with the k-{epsilon} model), salinity, water temperature, sediment, dissolved contaminants, and sediment-sorbed contaminants. Solving the Navier-Stokes equations using higher order correlations is not practical for regional modeling because of the prohibitive computational requirements; therefore, the turbulence modeling is a more practical approach. PNL applied the three-dimensional code, TEMPEST{copyright}/FLESCOT{copyright} with the k-{epsilon} model, to a very simple, hypothetical, two-dimensional, deep-ocean case, producing at least qualitatively appropriate results. However, more detailed testing should be performed for the further testing of the code. 46 refs., 39 figs., 6 tabs.

  1. 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.

  2. 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

  3. Simulated Damping of Periodic Fluctuations in Net Infiltration Within a Thick Unsaturated Zone in Southern Nevada: Implications For Radionuclide Transport

    NASA Astrophysics Data System (ADS)

    Ebel, B. A.; Nimmo, J. R.

    2009-12-01

    Arid and semiarid regions are historically preferred sites for radionuclide generating activities and waste disposal, in part because their unsaturated zones, typically having large thickness and low water content, are expected to inhibit the transport of contaminants to groundwater supplies. Through portions of the unsaturated zone that are heavily fractured, however, there is concern that transport in preferential flow paths might be relatively rapid on an episodic basis. Even so, fractured zones are commonly interrupted by lithologic units without substantial fractures, through which unsaturated flow might always be diffuse so as to damp out episodic fluctuations. In unsaturated-zone fractured units below such damping units, the initiation of preferential flow theoretically hinges on reaching a threshold moisture state, which depends on the magnitude of pressure and flux signals resulting from natural periodic variations in net infiltration. In diffuse unsaturated flow, periodic oscillations are damped to a quasi-steady state at sufficient distance from the inflow boundary. The resulting matric potential may be insufficient to trigger or sustain fracture flow through unsaturated media lying beneath those that facilitate damping. In general, shorter-period oscillations, longer distances of diffuse flow, and drier matrix conditions are conducive to damping. In this work we examine the damping of periodic recharge signals to a quasi-steady value, using analytical solutions for diffuse unsaturated flow, at Rainier Mesa and Shoshone Mountain in southern Nevada. Underground nuclear tests in previous decades introduced radionuclides into the unsaturated subsurface at these sites. Both sites have possible damping units greater than 100 m thick that are believed to be dominated by diffuse flow. Below these damping units lie fractured rocks in which preferential flow could resume, especially if the damping units are not sufficiently thick or dry. Effective damping of

  4. Surface Complexation of Actinides with Iron Oxides: Implications for Radionuclide Transport in Near-Surface Aquifers

    NASA Astrophysics Data System (ADS)

    Jerden, J. L.; Kropf, A. J.; Tsai, Y.

    2005-12-01

    The surface complexation of actinides with iron oxides plays a key role in actinide transport and retardation in geosphere-biosphere systems. The development of accurate actinide transport models therefore requires a mechanistic understanding of surface complexation reactions (i.e. knowledge of chemical speciation at mineral/fluid interfaces). Iron oxides are particularly important actinide sorbents due to their pH dependent surface charges, relatively high surface areas and ubiquity in oxic and suboxic near-surface systems. In this paper we present results from field and laboratory investigations that elucidate the mechanisms involved in binding uranium and neptunium to iron oxide mineral substrates in near neutral groundwaters. The field study involved sampling and characterizing uranium-bearing groundwaters and solids from a saprolite aquifer overlying an unmined uranium deposit in the Virginia Piedmont. The groundwaters were analyzed by inductively coupled mass spectrometry and ion chromatography and the aquifer solids were analyzed by electron microprobe. The laboratory study involved a series of batch sorption tests in which U(VI) and Np(V) were reacted with goethite, hematite and magnetite in simulated groundwaters. The pH, ionic strength, aging time, and sorbent/sorbate ratios were varied in these experiments. The oxidation state and coordination environment of neptunium in solutions and sorbents from the batch tests were characterized by X-ray absorption spectroscopy (XAS) at the Advanced Photon Source, Argonne National Laboratory. Results from this work indicate that, in oxidizing near-surface aquifers, the dissolved concentration of uranium may be limited to less than 30 parts per billion due to uptake by iron oxide mineral coatings and the precipitation of sparingly soluble U(VI) phosphate minerals. Results from the batch adsorption tests showed that, in near neutral groundwaters, a significant fraction of the uranium and neptunium adsorbed as strongly

  5. SURFACE COMPLEXATION OF ACTINIDES WITH IRON OXIDES: IMPLICATIONS FOR RADIONUCLIDE TRANSPORT IN NEAR-SURFACE AQUIFERS

    SciTech Connect

    J.L. Jerden Jr.; A.J. Kropf; Y. Tsai

    2005-08-25

    The surface complexation of actinides with iron oxides plays a key role in actinide transport and retardation in geosphere-biosphere systems. The development of accurate actinide transport models therefore requires a mechanistic understanding of surface complexation reactions (i.e. knowledge of chemical speciation at mineral/fluid interfaces). Iron oxides are particularly important actinide sorbents due to their pH dependent surface charges, relatively high surface areas and ubiquity in oxic and suboxic near-surface systems. In this paper we present results from field and laboratory investigations that elucidate the mechanisms involved in binding uranium and neptunium to iron oxide mineral substrates in near neutral groundwaters. The field study involved sampling and characterizing uranium-bearing groundwaters and solids from a saprolite aquifer overlying an unmined uranium deposit in the Virginia Piedmont. The groundwaters were analyzed by inductively coupled mass spectrometry and ion chromatography and the aquifer solids were analyzed by electron microprobe. The laboratory study involved a series of batch sorption tests in which U(VI) and Np(V) were reacted with goethite, hematite and magnetite in simulated groundwaters. The pH, ionic strength, aging time, and sorbent/sorbate ratios were varied in these experiments. The oxidation state and coordination environment of neptunium in solutions and sorbents from the batch tests were characterized by X-ray absorption spectroscopy (XAS) at the Advanced Photon Source, Argonne National Laboratory. Results from this work indicate that, in oxidizing near-surface aquifers, the dissolved concentration of uranium may be limited to less than 30 parts per billion due to uptake by iron oxide mineral coatings and the precipitation of sparingly soluble U(VI) phosphate minerals. Results from the batch adsorption tests showed that, in near neutral groundwaters, a significant fraction of the uranium and neptunium adsorbed as strongly

  6. Numerical simulation of the transport of a radionuclide chain in a rock medium.

    PubMed

    Sen, Soubhadra; Srinivas, C V; Baskaran, R; Venkatraman, B

    2015-03-01

    For the safe disposal of High Level Waste (HLW), a common practice is to bury the sealed container called canister containing the concentrated and vitrified waste deep inside the earth surface within a rocky medium. In the event of an accidental breach of such a canister, the sealed waste may come in contact of pore water. If this happens, then the parent nuclides present in the HLW and their daughters generated by the radioactive decay reaction start migrating through the surrounding rock medium due to the combined effect of advection and diffusion. The accurate estimation of the transport of such a chain through a rock is important for radiological safety. Here, we report a finite difference based numerical simulation to address the issue. To simplify the problem, we consider the rock to be a collection of identical parallel fractures separated by porous matrices of equal width with a source at one end. A Forward Time and Centered Space (FTCS) finite difference scheme is implemented to solve the set of coupled partial differential equations that govern the transport mechanism. The scheme is validated using the methods available in the literature and subsequently it is applied to estimate the time dependent buildup of the active elements of a chain. Two independent chains each with three members are considered for simulation to address the safety related issues. PMID:25574608

  7. 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.

  8. 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. PMID:20136119

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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

    2016-01-01

    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 (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. PMID:27184191

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. Radionuclide Behavior in Containments.

    2000-02-14

    MATADOR analyzes the transport and deposition of radionuclides as vapor or aerosol through Light Water Reactor (LWR) containments during severe accidents and calculates environmental release fractions of radionuclides as a function of time. It is intended for use in system risk studies. The principal output is information on the timing and magnitude of radionuclide releases to the environment as a result of severely degraded core accidents. MATADOR considers the transport of radionuclides through the containmentmore » and their removal by natural deposition and the operation of engineered safety systems such as sprays. Input data on the source term from the primary system, the containment geometry, and thermal-hydraulic conditions are required.« less

  2. 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.

  3. 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...

  4. 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.

  5. A reference skeletal dosimetry model for an adult male radionuclide therapy patient based on three-dimensional imaging and paired-image radiation transport

    NASA Astrophysics Data System (ADS)

    Shah, Amish P.

    The need for improved patient-specificity of skeletal dose estimates is widely recognized in radionuclide therapy. Current clinical models for marrow dose are based on skeletal mass estimates from a variety of sources and linear chord-length distributions that do not account for particle escape into cortical bone. To predict marrow dose, these clinical models use a scheme that requires separate calculations of cumulated activity and radionuclide S values. Selection of an appropriate S value is generally limited to one of only three sources, all of which use as input the trabecular microstructure of an individual measured 25 years ago, and the tissue mass derived from different individuals measured 75 years ago. Our study proposed a new modeling approach to marrow dosimetry---the Paired Image Radiation Transport (PIRT) model---that properly accounts for both the trabecular microstructure and the cortical macrostructure of each skeletal site in a reference male radionuclide patient. The PIRT model, as applied within EGSnrc, requires two sets of input geometry: (1) an infinite voxel array of segmented microimages of the spongiosa acquired via microCT; and (2) a segmented ex-vivo CT image of the bone site macrostructure defining both the spongiosa (marrow, endosteum, and trabeculae) and the cortical bone cortex. Our study also proposed revising reference skeletal dosimetry models for the adult male cancer patient. Skeletal site-specific radionuclide S values were obtained for a 66-year-old male reference patient. The derivation for total skeletal S values were unique in that the necessary skeletal mass and electron dosimetry calculations were formulated from the same source bone site over the entire skeleton. We conclude that paired-image radiation-transport techniques provide an adoptable method by which the intricate, anisotropic trabecular microstructure of the skeletal site; and the physical size and shape of the bone can be handled together, for improved

  6. TRANSPORTER POLYMORPHISMS AFFECT NORMAL PHYSIOLOGY, DISEASES, AND PHARMACOTHERAPY

    PubMed Central

    Sissung, Tristan M.; Troutman, Sarah M.; Campbell, Tessa J; Pressler, Heather M.; Sung, Hyeyoung; Bates, Susan E.; Figg, William D.

    2014-01-01

    Drug transporters mediate the movement of endobiotics and xenobiotics across biological membranes in multiple organs and in most tissues. As such, they are involved in physiology, development of disease, drug pharmacokinetics, and ultimately the clinical response to myriad medications. Genetic variants in transporters cause population-specific differences in drug transport and are responsible for considerable inter-individual variation in physiology and pharmacotherapy. The purpose of this review is to provide a broad overview of how inherited variants in transporters are associated with disease etiology, disease state, and the pharmacological treatment of diseases. Given that there are thousands of published papers related to the interplay between transporter genetics and medicine, this review will provide examples that exemplify the broader focus of the literature. PMID:22284781

  7. Resuspension and redistribution of radionuclides during grassland and forest fires in the Chernobyl exclusion zone: part II. Modeling the transport process.

    PubMed

    Yoschenko, V I; Kashparov, V A; Levchuk, S E; Glukhovskiy, A S; Khomutinin, Yu V; Protsak, V P; Lundin, S M; Tschiersch, J

    2006-01-01

    To predict parameters of radionuclide resuspension, transport and deposition during forest and grassland fires, several model modules were developed and adapted. Experimental data of controlled burning of prepared experimental plots in the Chernobyl exclusion zone have been used to evaluate the prognostic power of the models. The predicted trajectories and elevations of the plume match with those visually observed during the fire experiments in the grassland and forest sites. Experimentally determined parameters could be successfully used for the calculation of the initial plume parameters which provide the tools for the description of various fire scenarios and enable prognostic calculations. In summary, the model predicts a release of some per thousand from the radionuclide inventory of the fuel material by the grassland fires. During the forest fire, up to 4% of (137)Cs and (90)Sr and up to 1% of the Pu isotopes can be released from the forest litter according to the model calculations. However, these results depend on the parameters of the fire events. In general, the modeling results are in good accordance with the experimental data. Therefore, the considered models were successfully validated and can be recommended for the assessment of the resuspension and redistribution of radionuclides during grassland and forest fires in contaminated territories.

  8. 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.

  9. 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.

  10. 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. PMID:19419807

  11. 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

  12. 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

  13. Radionuclide Sensors for Water Monitoring

    SciTech Connect

    Grate, Jay W.; Egorov, Oleg B.; DeVol, Timothy A.

    2005-09-01

    Radionuclide contamination in the soil and groundwater at U.S. Department of Energy (DOE) sites is a severe problem that requires monitoring and remediation. Radionuclide measurement techniques are needed to monitor surface waters, groundwater, and process waters. Typically, water samples are collected and transported to an analytical laboratory, where costly radiochemical analyses are performed. To date, there has been very little development of selective radionuclide sensors for alpha- and beta-emitting radionuclides such as 90Sr, 99Tc, and various actinides of interest.

  14. 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

  15. Chemical factors affecting fission product transport in severe LMFBR accidents

    SciTech Connect

    Wichner, R.P.; Jolley, R.L.; Gat, U.; Rodgers, B.R.

    1984-10-01

    This study was performed as a part of a larger evaluation effort on LMFBR accident, source-term estimation. Purpose was to provide basic chemical information regarding fission product, sodium coolant, and structural material interactions required to perform estimation of fission product transport under LMFBR accident conditions. Emphasis was placed on conditions within the reactor vessel; containment vessel conditions are discussed only briefly.

  16. 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.

  17. 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

  18. The antiepileptic drug phenytoin affects sodium transport in toad epithelium.

    PubMed

    Suwalsky, Mario; Mennickent, Sigrid; Norris, Beryl; Cárdenas, Hernan

    2006-01-01

    The effects of phenytoin on isolated Pleurodema thaul toad skin were investigated. Low (micromolar) concentrations of the antiepileptic agent applied to the outside surface of the toad epithelium increased the electrical parameters (short-circuit current and potential difference) by over 40%, reflecting stimulation of Na(+) transport, whereas higher (millimolar concentrations, outside and inside surface) decreased both electric parameters, the effect being greater at the inside surface (40% and 80% decrease, respectively). The amiloride test showed that the stimulatory effect was accompanied by an increase and the inhibitory effect by a decrease in the sodium electromotive force (ENa). It is concluded that the drug interaction with membrane lipid bilayers might result in a distortion of the lipid-protein interface contributing to disturbance of Na(+) epithelial channel activity. After applying the Na(+)-K(+)-ATPase blocker ouabain and replacing the Na(+) ions in the outer Ringer's solution by choline, it was concluded that both active and passive transport are involved in sodium absorption, although active transport predominates. PMID:16314149

  19. 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 ...

  20. 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

  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. 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.

  3. Radionuclide transport in the vicinity of the repository and associated complementary cumulative distribution functions in the 1996 performance assessment for the Waste Isolation Pilot Plant

    SciTech Connect

    STOCKMAN,CHRISTINE T.; GARNER,J.W.; HELTON,JON CRAIG; JOHNSON,JAY DEAN; SHINTA,A.; SMITH,L.N.

    2000-05-22

    The following topics related to radionuclide transport in the vicinity of the repository in the 1996 performance assessment for the Waste Isolation Pilot Plant are presented (1) mathematical description of models, (2) uncertainty and sensitivity analysis results arising from subjective (i.e., epistemic) uncertainty for individual releases, (3) construction of complementary cumulative distribution functions (CCDFs) arising from stochastic (i.e., aleatory) uncertainty, and (4) uncertainty and sensitivity analysis results for CCDFs. The presented results indicate that no releases to the accessible environment take place due to radionuclide movement through the anhydrite marker beds, through the Dewey Lake Red Beds or directly to the surface, and also that the releases to the Culebra Dolomite are small. Even when the effects of uncertain analysis inputs are taken into account, the CCDFs for release to the Culebra Dolomite fall to the left of 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).

  4. Systems analysis, long-term radionuclide transport, and dose assessments, Waste Isolation Pilot Plant (WIPP), southeastern New Mexico, September 1989

    SciTech Connect

    Lappin, A.R.; Hunter, R.L.; Davies, P.B.; Borns, D.J. ); Reeves, M.; Pickens, J. ); Iuzzolino, H.J. )

    1990-12-01

    This study supports the Waste Isolation Pilot Plant (WIPP) Final Supplemental Environmental Impact Statement and has two main objectives. First, it describes current ideas about the characteristics and potential impacts of the disturbed-rock zone (DRZ) known to develop with time around excavations at the WIPP horizon. Second, it presents new calculations of radionuclide migration within and from the WIPP repository for steady-state undisturbed conditions and for two cases that consider human intrusion into the repository. At the WIPP, the presence of a DRZ has been confirmed by geophysical studies, gas-flow tests, and direct observations. The DRZ will allow gas or brine from waste-emplacement panels to bypass panel seals and flow into adjacent portions of the underground workings unless preventive measures are taken. Revised calculations of the undisturbed performance of the repository indicate that no radionuclides will be released into the Culebra Dolomite within the regulatory period of 10,000 years. The human-intrusion calculations included here assume a connection between the WIPP repository, an occurrence of pressurized brine within the underlying Castile Formation, and the overlying Culebra Dolomite. 61 refs., 40 figs., 16 tabs.

  5. 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)

  6. 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

  7. The antiepileptic drug carbamazepine affects sodium transport in toad epithelium.

    PubMed

    Suwalsky, Mario; Mennickent, Sigrid; Norris, Beryl; Cardenas, Hernán

    2006-09-01

    The present work investigates the effects of the antiepileptic drug carbamazepine (CBZ) on sodium transport in the isolated skin of the toad Pleurodema thaul. A submaximal concentration of the drug (0.2 mM) applied to the outer surface of the epithelium increased the electrical parameters short-circuit current (Isc) and potential difference (PD) by over 28%, whereas only a higher concentration (1 mM) induced over a 45% decrease in these parameters when applied to the inner surface. The amiloride test showed that the outer surface stimulatory effect was accompanied by an increase and the inner surface inhibitory effect by a decrease in the sodium electromotive force (ENa). Exploration of these effects of CBZ on the outer surface showed that 0.2 mM increased net Na+ (22Na) influx by 20% and 0.6 mM CBZ decreased Na+ mucosa-serosa flux by 19%, a result in agreement with the finding that higher concentrations of CBZ applied to the inner surface not only decreased ENa but also sodium conductance (GNa). PMID:16542818

  8. 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

  9. Radionuclide Decay and In-growth Technical Basis Document

    SciTech Connect

    Kersting, A B; Finnegan, D L; Tompson, A F B; Esser, B K; Smith, D K; Zavarin, M; Bruton, C J; Pawloski, G A

    2003-07-01

    specific radionuclide at any given time is a function of the initial amount of radioactivity, the decay rate and in-growth from parent radionuclides. The in-growth of radioactivity is the additional amount of radioactivity for a given radionuclide that comes from the decay of the parent isotopes. In this report, decay and in-growth of radionuclides from the RST are evaluated over the 1000-year time frame in order to determine whether coupled in-growth and decay affect the relative abundance of any RST radionuclide. In addition, it is also necessary to identify whether any new derivative radionuclides not initially produced by the nuclear test but exist now as a result of in-growth from a parent radionuclide One of the major goals of this report is to simplify the transport modeler's task by pointing out where in-growth is unimportant and where it needs to be considered. The specific goals of this document are to evaluate radionuclide decay chains and provide specific recommendations for incorporating radionuclide daughters of concern in the calculation of the radionuclide inventory.

  10. 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.

  11. Initial Radionuclide Inventories

    SciTech Connect

    Miller, H

    2005-07-12

    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

  12. 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

  13. 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

  14. Relationship between Microtubule Network Structure and Intracellular Transport in Cultured Endothelial Cells Affected by Shear Stress

    NASA Astrophysics Data System (ADS)

    Kudo, Susumu; Ikezawa, Kenji; Ikeda, Mariko; Tanishita, Kazuo

    Endothelial cells (ECs) that line the inner surface of blood vessels are barriers to the transport of various substances into or from vessel walls, and are continuously exposed to shear stress induced by blood flow in vivo. Shear stress affects the cytoskeleton (e.g., microtubules, microfilaments, intermediate filaments), and affects the transport of macromolecules. Here, the relationship between the microtubule network structure and this transport process for albumin uptake within cultured aortic endothelial cells affected by shear stress was studied. Based on fluorescent images of albumin uptake obtained by using confocal laser scanning microscopy (CLSM), both the microtubule network and albumin uptake in ECs were disrupted by colchicine and were affected by shear stress loading.

  15. Scientific Analysis Cover Sheet for Radionuclide Screening

    SciTech Connect

    G. Ragan

    2002-08-09

    pressurized water reactor (PWR) fuel, U.S. Department of Energy (DOE) spent nuclear fuel (DSNF), and high-level waste (HLW). Average and outlying (high burnup, high initial enrichment, low age, or otherwise exceptional) forms of each waste-form type are considered. This analysis has been prepared in accordance with a technical work plan (BSC 2002c). In a review of Revision 00 of this radionuclide screening analysis, the NRC found that ''processes that affect transport in the biosphere, such as uptake by plants and bioaccumulation are not accounted for'' and that ''the direct exposure pathway is not accounted for'' (Beckman 2001, Section 5.3.2.1). The NRC also found that the solubility and sorption classes were too broadly defined, noting, for example, that Se is in the same solubility and sorptivity groups as Np and U, yet is ''more soluble than Np and U by several orders of magnitude'' (Beckman 2001, Section 5.3.2.1). This revision seeks to build upon the strengths of the earlier screening method while responding to the specific concerns raised by the NRC and other reviewers. In place of simple inhalation and ingestion dose conversion factors, the revised radionuclide screening uses screening factors that also take into account soil accumulation, uptake by plants, exposure to contaminated ground, and other features of the biosphere that were neglected in the previous screening. Whereas the previous screening analysis allowed only two solubility classes (soluble and insoluble), the revised screening introduces an intermediate solubility class to better segregate the radionuclides into transport groups.

  16. 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.

  17. Biochar pyrolyzed at two temperatures affects Escherichia coli transport through a sandy soil.

    PubMed

    Bolster, Carl H; Abit, Sergio M

    2012-01-01

    The incorporation of biochar into soils has been proposed as a means to sequester carbon from the atmosphere. An added environmental benefit is that biochar has also been shown to increase soil retention of nutrients, heavy metals, and pesticides. The goal of this study was to evaluate whether biochar amendments affect the transport of Escherichia coli through a water-saturated soil. We looked at the transport of three E. coli isolates through 10-cm columns packed with a fine sandy soil amended with 2 or 10% (w/w) poultry litter biochar pyrolyzed at 350 or 700°C. For all three isolates, mixing the high-temperature biochar at a rate of 2% into the soil had no impact on transport behavior. When added at a rate of 10%, a reduction of five orders of magnitude in the amount of E. coli transported through the soil was observed for two of the isolates, and a 60% reduction was observed for the third isolate. Mixing the low-temperature biochar into the soil resulted in enhanced transport through the soil for two of the isolates, whereas no significant differences in transport behavior were observed between the low-temperature and high-temperature biochar amendments for one isolate. Our results show that the addition of biochar can affect the retention and transport behavior of E. coli and that biochar application rate, biochar pyrolysis temperature, and bacterial surface characteristics were important factors determining the transport of E. coli through our test soil. PMID:22218181

  18. New best estimates for radionuclide solid-liquid distribution coefficients in soils. Part 2: naturally occurring radionuclides.

    PubMed

    Vandenhove, H; Gil-García, C; Rigol, A; Vidal, M

    2009-09-01

    Predicting the transfer of radionuclides in the environment for normal release, accidental, disposal or remediation scenarios in order to assess exposure requires the availability of an important number of generic parameter values. One of the key parameters in environmental assessment is the solid liquid distribution coefficient, K(d), which is used to predict radionuclide-soil interaction and subsequent radionuclide transport in the soil column. This article presents a review of K(d) values for uranium, radium, lead, polonium and thorium based on an extensive literature survey, including recent publications. The K(d) estimates were presented per soil groups defined by their texture and organic matter content (Sand, Loam, Clay and Organic), although the texture class seemed not to significantly affect K(d). Where relevant, other K(d) classification systems are proposed and correlations with soil parameters are highlighted. The K(d) values obtained in this compilation are compared with earlier review data.

  19. Pulse exposure of cultured rat neurons to aluminum-maltol affected the axonal transport system.

    PubMed

    Kashiwagi, Y; Nakamura, Y; Miyamae, Y; Hashimoto, R; Takeda, M

    1998-08-01

    Although chronic aluminum neurotoxicity has been well established, the mechanism of the toxicity has not been elucidated yet. In order to simplify the study of the aluminum neurotoxicity, we employed the pulse exposure of cultured rat cortical neurons to 250 microM aluminum-maltol for 1 h at the early stage (6 h after plating), which resulted in abnormal distribution of neurofilament L (NFL) and fast axonal transported proteins, whereas the axonal transport of tubulin, actin, and clathrin were not impaired. Otherwise, the pulse exposure of neurons at the late stage (4 days after plating) to the same concentration of aluminum-maltol did not affect the cell morphology and the distribution of NFL. The pulse exposure of cultured neurons to aluminum-maltol at the early stage might affect the axonal transport system of NFL and fast axonal transported proteins. PMID:9756345

  20. 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.

  1. 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.

  2. 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. PMID:25874817

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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

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

    PubMed

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

    2012-01-01

    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.

  9. 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.

  10. Mutations in the white gene of Drosophila melanogaster affecting ABC transporters that determine eye colouration.

    PubMed

    Mackenzie, S M; Brooker, M R; Gill, T R; Cox, G B; Howells, A J; Ewart, G D

    1999-07-15

    The white, brown and scarlet genes of Drosophila melanogaster encode proteins which transport guanine or tryptophan (precursors of the red and brown eye colour pigments) and belong to the ABC transporter superfamily. Current models envisage that the white and brown gene products interact to form a guanine specific transporter, while white and scarlet gene products interact to form a tryptophan transporter. In this study, we report the nucleotide sequence of the coding regions of five white alleles isolated from flies with partially pigmented eyes. In all cases, single amino acid changes were identified, highlighting residues with roles in structure and/or function of the transporters. Mutations in w(cf) (G589E) and w(sat) (F590G) occur at the extracellular end of predicted transmembrane helix 5 and correlate with a major decrease in red pigments in the eyes, while brown pigments are near wild-type levels. Therefore, those residues have a more significant role in the guanine transporter than the tryptophan transporter. Mutations identified in w(crr) (H298N) and w(101) (G243S) affect amino acids which are highly conserved among the ABC transporter superfamily within the nucleotide binding domain. Both cause substantial and similar decreases of red and brown pigments indicating that both tryptophan and guanine transport are impaired. The mutation identified in w(Et87) alters an amino acid within an intracellular loop between transmembrane helices 2 and 3 of the predicted structure. Red and brown pigments are reduced to very low levels by this mutation indicating this loop region is important for the function of both guanine and tryptophan transporters. PMID:10407069

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. 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.

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

    PubMed Central

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

    2015-01-01

    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. PMID:26209364

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

    PubMed

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

    2015-10-01

    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. PMID:26209364

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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

  11. Epoxyeicosatrienoic Acids Affect Electrolyte Transport in Renal Tubular Epithelial Cells: Dependence on Cyclooxygenase and Cell Polarity

    PubMed Central

    Nüsing, Rolf M.; Schweer, Horst; Fleming, Ingrid; Zeldin, Darryl C.; Wegmann, Markus

    2007-01-01

    We investigated the effects of epoxyeicosatrienoic acids (EETs) on ion transport in the polarized renal distal tubular cell line, MDCK C7. Of the four EET regioisomers (5,6-EET, 8,9-EET, 11,12-EET, and 14,15-EET) studied, only apical, but not basolateral, application of 5,6-EET increased short circuit current (Isc) with kinetics similar to those of arachidonic acid. The ion transport was blocked by preincubation with the cyclooxygenase inhibitor indomethacin or with the chloride channel blocker NPPB. Further, both a Cl−-free bath solution and the Ca2+ antagonist verapamil blocked 5,6-EET-induced ion transport. Although the presence of the PGE2 receptors EP2, EP3, and EP4 was demonstrated, apically added PGE2 was ineffective and basolaterally added PGE2 caused a different kinetics in ion transport compared to 5,6-EET. Moreover, PGE2 sythesis in MDCK C7 cells was unaffected by 5,6-EET treatment. GC/MS/MS analysis of cell supernatants revealed the presence of the biologically inactive 5,6-dihydroxy-PGE1 in 5,6-EET-treated cells, but not in control cells. Indomethacin suppressed the formation of 5,6-dihydroxy-PGE1. 5,6-epoxy-PGE1 the precursor of 5,6-dihydroxy-PGE1, caused a similar ion transport as 5,6-EET. Cytochrome P450 enzymes homolog to human CYP2C8, CYP2C9, and CYP2J2 protein were detected immunologically in the MDCK C7 cells. Our findings suggest that 5,6-EET affects Cl-transport in renal distal tubular cells independent of PGE2 but by a mechanism, dependent on its conversion to 5,6-epoxy-PGE1 by cyclooxygenase. We suggest a role for this P450 epoxygenase product in the regulation of electrolyte transport, especially as a saluretic compound acting from the luminal side of tubular cells in the mammalian kidney. PMID:17494091

  12. Defective copper transport in the copt5 mutant affects cadmium tolerance.

    PubMed

    Carrió-Seguí, Angela; Garcia-Molina, Antoni; Sanz, Amparo; Peñarrubia, Lola

    2015-03-01

    Cadmium toxicity interferes with essential metal homeostasis, which is a problem for both plant nutrition and the consumption of healthy food by humans. Copper uptake is performed by the members of the Arabidopsis high affinity copper transporter (COPT) family. One of the members, COPT5, is involved in copper recycling from the vacuole toward the cytosolic compartment. We show herein that copt5 mutants are more sensitive to cadmium stress than wild-type plants, as indicated by reduced growth. Exacerbated cadmium toxicity in copt5 mutants is due specifically to altered copper traffic through the COPT5 transporter. Three different processes which have been shown to affect cadmium tolerance are altered in copt5 mutants. First, ethylene biosynthesis diminishes under copper deficiency and, in the presence of cadmium, ethylene production diminishes further. Copper deficiency responses are also attenuated under cadmium treatment. Remarkably, while copt5 roots present higher oxidative stress toxicity symptoms than controls, aerial copt5 parts display lower oxidative stress, as seen by reduced cadmium delivery to shoots. Taken together, these results demonstrate that copper transport plays a key role in cadmium resistance, and suggest that oxidative stress triggers an NADPH oxidase-mediated signaling pathway, which contributes to cadmium translocation and basal plant resistance. The slightly lower cadmium levels that reach aerial parts in the copt5 mutants, irrespective of the copper content in the media, suggest a new biotechnological approach to minimize toxic cadmium entry into food chains.

  13. 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. PMID:20163088

  14. 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.

  15. Gallbladder radionuclide scan

    MedlinePlus

    Radionuclide - gallbladder; Gallbladder scan; Biliary scan; Cholescintigraphy: HIDA; Hepatobiliary nuclear imaging scan ... small amount of morphine. This can help the radionuclide get into the gallbladder. The morphine may cause ...

  16. Inhibition of ABC transport proteins by oil sands process affected water.

    PubMed

    Alharbi, Hattan A; Saunders, David M V; Al-Mousa, Ahmed; Alcorn, Jane; Pereira, Alberto S; Martin, Jonathan W; Giesy, John P; Wiseman, Steve B

    2016-01-01

    The ATP-binding cassette (ABC) superfamily of transporter proteins is important for detoxification of xenobiotics. For example, ABC transporters from the multidrug-resistance protein (MRP) subfamily are important for excretion of polycyclic aromatic hydrocarbons (PAHs) and their metabolites. Effects of chemicals in the water soluble organic fraction of relatively fresh oil sands process affected water (OSPW) from Base Mine Lake (BML-OSPW) and aged OSPW from Pond 9 (P9-OSPW) on the activity of MRP transporters were investigated in vivo by use of Japanese medaka at the fry stage of development. Activities of MRPs were monitored by use of the lipophilic dye calcein, which is transported from cells by ABC proteins, including MRPs. To begin to identify chemicals that might inhibit activity of MRPs, BML-OSPW and P9-OSPW were fractionated into acidic, basic, and neutral fractions by use of mixed-mode sorbents. Chemical compositions of fractions were determined by use of ultrahigh resolution orbitrap mass spectrometry in ESI(+) and ESI(-) mode. Greater amounts of calcein were retained in fry exposed to BML-OSPW at concentration equivalents greater than 1× (i.e., full strength). The neutral and basic fractions of BML-OSPW, but not the acidic fraction, caused greater retention of calcein. Exposure to P9-OSPW did not affect the amount of calcein in fry. Neutral and basic fractions of BML-OSPW contained relatively greater amounts of several oxygen-, sulfur, and nitrogen-containing chemical species that might inhibit MRPs, such as O(+), SO(+), and NO(+) chemical species, although secondary fractionation will be required to conclusively identify the most potent inhibitors. Naphthenic acids (O2(-)), which were dominant in the acidic fraction, did not appear to be the cause of the inhibition. This is the first study to demonstrate that chemicals in the water soluble organic fraction of OSPW inhibit activity of this important class of proteins. However, aging of OSPW attenuates

  17. Inhibition of ABC transport proteins by oil sands process affected water.

    PubMed

    Alharbi, Hattan A; Saunders, David M V; Al-Mousa, Ahmed; Alcorn, Jane; Pereira, Alberto S; Martin, Jonathan W; Giesy, John P; Wiseman, Steve B

    2016-01-01

    The ATP-binding cassette (ABC) superfamily of transporter proteins is important for detoxification of xenobiotics. For example, ABC transporters from the multidrug-resistance protein (MRP) subfamily are important for excretion of polycyclic aromatic hydrocarbons (PAHs) and their metabolites. Effects of chemicals in the water soluble organic fraction of relatively fresh oil sands process affected water (OSPW) from Base Mine Lake (BML-OSPW) and aged OSPW from Pond 9 (P9-OSPW) on the activity of MRP transporters were investigated in vivo by use of Japanese medaka at the fry stage of development. Activities of MRPs were monitored by use of the lipophilic dye calcein, which is transported from cells by ABC proteins, including MRPs. To begin to identify chemicals that might inhibit activity of MRPs, BML-OSPW and P9-OSPW were fractionated into acidic, basic, and neutral fractions by use of mixed-mode sorbents. Chemical compositions of fractions were determined by use of ultrahigh resolution orbitrap mass spectrometry in ESI(+) and ESI(-) mode. Greater amounts of calcein were retained in fry exposed to BML-OSPW at concentration equivalents greater than 1× (i.e., full strength). The neutral and basic fractions of BML-OSPW, but not the acidic fraction, caused greater retention of calcein. Exposure to P9-OSPW did not affect the amount of calcein in fry. Neutral and basic fractions of BML-OSPW contained relatively greater amounts of several oxygen-, sulfur, and nitrogen-containing chemical species that might inhibit MRPs, such as O(+), SO(+), and NO(+) chemical species, although secondary fractionation will be required to conclusively identify the most potent inhibitors. Naphthenic acids (O2(-)), which were dominant in the acidic fraction, did not appear to be the cause of the inhibition. This is the first study to demonstrate that chemicals in the water soluble organic fraction of OSPW inhibit activity of this important class of proteins. However, aging of OSPW attenuates

  18. 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.

  19. 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.

  20. 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. PMID:16121503

  1. Lactate kinetics of rainbow trout during graded exercise: do catheters affect the cost of transport?

    PubMed

    Teulier, Loïc; Omlin, Teye; Weber, Jean-Michel

    2013-12-15

    Changes in lactate kinetics as a function of exercise intensity have never been measured in an ectotherm. Continuous infusion of a tracer is necessary to quantify rates of lactate appearance (Ra) and disposal (Rd), but it requires double catheterization, which could interfere with swimming. Using rainbow trout, our goals were to: (1) determine the potential effects of catheters and blood sampling on metabolic rate (O2), total cost of transport (TCOT), net cost of transport (NCOT) and critical swimming speed (Ucrit), and (2) monitor changes in lactate fluxes during prolonged, steady-state swimming or graded swimming from rest to Ucrit. This athletic species maintains high baseline lactate fluxes of 24 μmol kg(-1) min(-1) that are only increased at intensities >2.4 body lengths (BL) s(-1) or 85% Ucrit. As the fish reaches Ucrit, Ra is more strongly stimulated (+67% to 40.4 μmol kg(-1) min(-1)) than Rd (+41% to 34.7 μmol kg(-1) min(-1)), causing a fourfold increase in blood lactate concentration. Without this stimulation of Rd during intense swimming, lactate accumulation would double. By contrast, steady-state exercise at 1.7 BL s(-1) increases lactate fluxes to ~30 μmol kg(-1) min(-1), with a trivial mismatch between Ra and Rd that only affects blood concentration minimally. Results also show that the catheterizations and blood sampling needed to measure metabolite kinetics in exercising fish have no significant impact on O2 or TCOT. However, these experimental procedures affect locomotion energetics by increasing NCOT at high speeds and by decreasing Ucrit.

  2. Aquaporin-9 and urea transporter-A gene deletions affect urea transmembrane passage in murine hepatocytes.

    PubMed

    Jelen, Sabina; Gena, Patrizia; Lebeck, Janne; Rojek, Aleksandra; Praetorius, Jeppe; Frøkiaer, Jørgen; Fenton, Robert A; Nielsen, Søren; Calamita, Giuseppe; Rützler, Michael

    2012-12-01

    In mammals, the majority of nitrogen from protein degradation is disposed of as urea. Several studies have partly characterized expression of urea transporters (UTs) in hepatocytes, where urea is produced. Nevertheless, the contribution of these proteins to hepatocyte urea permeability (P(urea)) and their role in liver physiology remains unknown. The purpose of this study was to biophysically examine hepatocyte urea transport. We hypothesized that the water, glycerol, and urea channel aquaporin-9 (AQP9) is involved in hepatocyte urea release. Stopped-flow light-scattering measurements determined that the urea channel inhibitors phloretin and dimethylurea reduced urea permeability of hepatocyte basolateral membranes by 70 and 40%, respectively. In basolateral membranes isolated from AQP9(-/-) and UT-A1/3(-/-) single-knockout and AQP9(-/-):UT-A1/3(-/-) double-knockout mice, P(urea) was decreased by 30, 40, and 76%, respectively, compared with AQP9(+/-):UT-A1/3(+/-) mice. However, expression analysis by RT-PCR did not identify known UT-A transcripts in liver. High-protein diet followed by 24-h fasting affected the concentrations of urea and ammonium ions in AQP9(-/-) mouse liver and plasma without generating an apparent tissue-to-plasma urea gradient. We conclude that AQP9 and unidentified UT-A urea channels constitute primary but redundant urea facilitators in murine hepatocytes.

  3. 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

  4. 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.

  5. 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

  6. Ssh4, Rcr2 and Rcr1 affect plasma membrane transporter activity in Saccharomyces cerevisiae.

    PubMed

    Kota, Jhansi; Melin-Larsson, Monika; Ljungdahl, Per O; Forsberg, Hanna

    2007-04-01

    Nutrient uptake in the yeast Saccharomyces cerevisiae is a highly regulated process. Cells adjust levels of nutrient transporters within the plasma membrane at multiple stages of the secretory and endosomal pathways. In the absence of the ER-membrane-localized chaperone Shr3, amino acid permeases (AAP) inefficiently fold and are largely retained in the ER. Consequently, shr3 null mutants exhibit greatly reduced rates of amino acid uptake due to lower levels of AAPs in their plasma membranes. To further our understanding of mechanisms affecting AAP localization, we identified SSH4 and RCR2 as high-copy suppressors of shr3 null mutations. The overexpression of SSH4, RCR2, or the RCR2 homolog RCR1 increases steady-state AAP levels, whereas the genetic inactivation of these genes reduces steady-state AAP levels. Additionally, the overexpression of any of these suppressor genes exerts a positive effect on phosphate and uracil uptake systems. Ssh4 and Rcr2 primarily localize to structures associated with the vacuole; however, Rcr2 also localizes to endosome-like vesicles. Our findings are consistent with a model in which Ssh4, Rcr2, and presumably Rcr1, function within the endosome-vacuole trafficking pathway, where they affect events that determine whether plasma membrane proteins are degraded or routed to the plasma membrane.

  7. 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

  8. 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

  9. 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.

  10. 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

  11. 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

  12. 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

  13. Quantitative radionuclide angiocardiography

    SciTech Connect

    Scholz, P.M.; Rerych, S.K.; Moran, J.F.; Newman, G.E.; Douglas, J.M.; Sabiston, D.C. Jr.; Jones, R.H.

    1980-01-01

    This study introduces a new method for calculating actual left ventricular volumes and cardiac output from data recorded during a single transit of a radionuclide bolus through the heart, and describes in detail current radionuclide angiocardiography methodology. A group of 64 healthy adults with a wide age range were studied to define the normal range of hemodynamic parameters determined by the technique. Radionuclide angiocardiograms were performed in patients undergoing cardiac catherization to validate the measurements. In 33 patients studied by both techniques on the same day, a close correlation was documented for measurement of ejection fraction and end-diastolic volume. To validate the method of volumetric cardiac output calcuation, 33 simultaneous radionuclide and indocyanine green dye determinations of cardiac output were performed in 18 normal young adults. These independent comparisons of radionuclide measurements with two separate methods document that initial transit radionuclide angiocardiography accurately assesses left ventricular function.

  14. 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

  15. Increased Seasonal Variation in Serotonin Transporter Binding in Seasonal Affective Disorder.

    PubMed

    Tyrer, Andrea E; Levitan, Robert D; Houle, Sylvain; Wilson, Alan A; Nobrega, José N; Meyer, Jeffrey H

    2016-09-01

    Seasonal affective disorder (SAD) is highly prevalent with rates of 1-6% and greater prevalence at more extreme latitudes; however, there are almost no direct brain investigations of this disorder. In health, serotonin transporter binding potential (5-HTT BPND), an index of 5-HTT levels, is greater throughout the brain in fall-winter compared with spring-summer. We hypothesized that in SAD, this seasonal variation would be greater in brain regions containing structures that regulate affect such as the prefrontal and anterior cingulate cortices (PFC and ACC). Furthermore, given the dimensional nature of SAD symptoms, it was hypothesized that seasonal fluctuation of 5-HTT BPND in the PFC and ACC would be greatest in severe SAD. Twenty SAD and twenty healthy participants underwent [(11)C]DASB positron emission tomography scans in summer and winter to measure seasonal variation in [(11)C]DASB 5-HTT BPND. Seasonal increases in [(11)C]DASB 5-HTT BPND were greater in SAD compared with healthy in the PFC and ACC, primarily due to differences between severe SAD and healthy (severe SAD vs healthy; Mann-Whitney U, U=42.5 and 37.0, p=0.005 and 0.003, respectively; greater magnitude in severe SAD of 35.10 and 14.23%, respectively), with similar findings observed in other regions (U=40.0-62.0, p=0.004-0.048; greater magnitude in severe SAD of 13.16-17.49%). To our knowledge, this is the first brain biomarker identified in SAD. This creates a new opportunity for phase 0 studies to target this phenotype and optimize novel prevention/treatment strategies for SAD.

  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. Dust-storm dynamics over Sistan region, Iran: Seasonality, transport characteristics and affected areas

    NASA Astrophysics Data System (ADS)

    Rashki, A.; Kaskaoutis, D. G.; Francois, P.; Kosmopoulos, P. G.; Legrand, M.

    2015-03-01

    The present work examines the seasonality, dust-plume altitudinal variation and affected areas for dust storms originated from the Sistan region, southeastern Iran during the summer (June-September) months of the period 2001-2012 synthesizing local meteorological records, satellite observations (TOMS, OMI, METEOSAT, MODIS) and HYSPLIT forward trajectories. Dust-storm days (356 in total) are associated with visibility below 1 km at Zabol, Iran meteorological station with higher frequency and intensity in June and July. Monthly-mean composite maps of TOMS and OMI AI show high (>3-3.5) values over Sistan and nearby downwind areas. HYSPLIT forward-trajectory analysis at 500 m for air masses originated from Sistan on the dust-storm days shows that they usually follow an anti-clockwise transport direction at elevations usually below 2 km, initially moving southwards and then shifting to east-northeast when they are approaching the Arabian Sea coast. This is the result of the influence of the local topography and formation of thermal low-pressure systems over the arid lands. It is found that in few cases the dust storms from Sistan affect central/south Arabian Sea and India, while they control the aerosol loading over northernmost Arabian Sea. The Infrared Difference Dust Index (IDDI) images, which represent brightness temperature reduction due to dust presence over land, are used at specific periods of persistent dust storms over Sistan, confirming the main pathways of the dust plumes and illustrating the importance of the region as one of the most active dust sources in southwest Asia.

  18. Food chain transport of nanoparticles affects behaviour and fat metabolism in fish.

    PubMed

    Cedervall, Tommy; Hansson, Lars-Anders; Lard, Mercy; Frohm, Birgitta; Linse, Sara

    2012-01-01

    Nano-sized (10(-9)-10(-7) m) particles offer many technical and biomedical advances over the bulk material. The use of nanoparticles in cosmetics, detergents, food and other commercial products is rapidly increasing despite little knowledge of their effect on organism metabolism. We show here that commercially manufactured polystyrene nanoparticles, transported through an aquatic food chain from algae, through zooplankton to fish, affect lipid metabolism and behaviour of the top consumer. At least three independent metabolic parameters differed between control and test fish: the weight loss, the triglycerides∶cholesterol ratio in blood serum, and the distribution of cholesterol between muscle and liver. Moreover, we demonstrate that nanoparticles bind to apolipoprotein A-I in fish serum in-vitro, thereby restraining them from properly utilising their fat reserves if absorbed through ingestion. In addition to the metabolic effects, we show that consumption of nanoparticle-containing zooplankton affects the feeding behaviour of the fish. The time it took the fish to consume 95% of the food presented to them was more than doubled for nanoparticle-exposed compared to control fish. Since many nano-sized products will, through the sewage system, end up in freshwater and marine habitats, our study provides a potential bioassay for testing new nano-sized material before manufacturing. In conclusion, our study shows that from knowledge of the molecular composition of the protein corona around nanoparticles it is possible to make a testable molecular hypothesis and bioassay of the potential biological risks of a defined nanoparticle at the organism and ecosystem level.

  19. 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

  20. 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

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

    PubMed

    Li, Yan; Wang, Lei; Zhou, Jiawei; Li, Fenge

    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

  2. The quantification of dietary intake, digestion and metabolism in farm livestock and its relevance to the study of radionuclide uptake.

    PubMed

    Mayes, R W

    1989-09-01

    The transfer coefficient and biological half-life have been widely used to describe the uptake of radionuclides by farm animals. However, these parameters may be inadequate, for they take little account of the effects of the processes occurring in the animal upon the behaviour of a radionuclide. The aim of this paper is to review techniques which could be used to study the uptake of dietary radionuclides by farm animals. The main factors affecting uptake can be categorised in terms of intake, digestion and absorption, and metabolism. The estimation of the intake of a radionuclide by grazing animals is difficult. Intake estimation by determining amounts of standing herbage before and after grazing is rarely a valid method because of herbage growth. Methods based on animal measurements have wider application. Many intake methods give short-term estimates (measured over a few hours), whereas for most radionuclide studies, longer-term estimates (over days or weeks) are required. The most suitable methods use indigestible markers to determine the output of faeces and the digestibility of grazed herbage. Considerable variability in the distribution of radionuclides may exist among different plant species. To accurately estimate radionuclide intake on mixed pastures it is necessary to determine the plant species composition of the diet of animals; present methods may be inadequate and new techniques may be required. If contaminated, the drinking-water intake by animals would need to be determined. The processes of digestion (the physical disintegration and chemical breakdown by gut microbes and secreted enzymes) may affect the radionuclide uptake by an animal. Other factors, including the chemical form of the radionuclide, rate of passage of material along the gut, degree of incorporation into microbial tissue, and the absorption mechanism might also affect the degree to which the radionuclide can cross the gut wall. The apparent absorption coefficient (apparent

  3. 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

  4. Identification of IAA transport inhibitors including compounds affecting cellular PIN trafficking by two chemical screening approaches using maize coleoptile systems.

    PubMed

    Nishimura, Takeshi; Matano, Naoyuki; Morishima, Taichi; Kakinuma, Chieko; Hayashi, Ken-Ichiro; Komano, Teruya; Kubo, Minoru; Hasebe, Mitsuyasu; Kasahara, Hiroyuki; Kamiya, Yuji; Koshiba, Tomokazu

    2012-10-01

    The monocot coleoptile tip region has been generally supposed to be the source of IAA to supply IAA to basal parts by the polar IAA transport system, which results in gravi- and phototropic curvature of coleoptiles. Based on this IAA transport system and gravitropism of maize coleoptiles, we have developed two screening methods to identify small molecules from a large chemical library that inhibit IAA transport. The methods detect molecules that affect (i) gravitropic curvature of coleoptiles; and (ii) the amount of IAA transported from the tip. From 10,000 chemicals, eight compounds were identified and categorized into two groups. Four chemicals in group A decreased IAA transport from the tip, and increased endogenous IAA levels in the tip. The structures of two compounds resembled that of 1-N-naphthylphthalamic acid (NPA), but those of the other two differed from structures of known IAA transport inhibitors. Four chemicals in group B strongly inhibited IAA transport from the tip, but IAA levels at the tip were only slightly affected. At higher concentrations, group B compounds inhibited germination of Arabidopsis, similarly to brefeldin A (BFA). Analysis of the cellular distribution of PIN2-green fluorescent protein (GFP) and PIN1-GFP in Arabidopsis revealed that one of the four chemicals in group B induced internalization of PIN1 and PIN2 proteins into vesicles smaller than BFA bodies, suggesting that this compound affects cellular vesicle trafficking systems related to PIN trafficking. The eight chemicals identified here will be a useful tool for understanding the mechanisms of IAA transport in plants. PMID:22875609

  5. 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.

  6. Lung vitamin E transport processes are affected by both age and environmental oxidants in mice

    SciTech Connect

    Valacchi, Giuseppe . E-mail: gvalacchi@ucdavis.edu; Vasu, Vihas T.; Yokohama, Wallace; Corbacho, Ana M.; Phung, Anh; Lim, Yunsook; Aung, Hnin Hnin; Cross, Carroll E.; Davis, Paul A.

    2007-07-15

    Despite the physiological importance of alpha-tocopherol (AT), the molecular mechanisms involved in maintaining cellular and tissue tocopherol levels remain to be fully characterized. Scavenger receptor B1 (SRB1), one of a large family of scavenger receptors, has been shown to facilitate AT transfer from HDL to peripheral tissues via apo A-1-mediated processes and to be important in the delivery of AT to the lung cells. In the present studies the effects of age and two environmental oxidants ozone (O{sub 3}) (0.25 ppm 6 h/day) and cigarette smoke (CS) (60 mg/m{sup 3} 6 h/day) for 4 days on selected aspects of AT transport in murine lung tissues were assessed. While AT levels were 25% higher (p < 0.05) and 15% lower (p < 0.05) in plasma and lung tissue, respectively, in aged versus young mice, acute environmental exposure to O{sub 3} or CS at the doses used had no effect. Gene expression levels, determined by RT-PCR of AT transport protein (ATTP), SRB1, CD36, ATP binding cassette 3 (ABCA3) and ABCA1 and protein levels, determined by Western blots for SRB1, ATTP and ABCA1 were assessed. Aged mouse lung showed a lower levels of ATTP, ABCA3 and SRB1 and a higher level CD36 and ABCA1. Acute exposure to either O{sub 3} or CS induced declines in ATTP and SRB1 in both aged and young mice lung. CD36 increased in both young and aged mice lung upon exposure to O{sub 3} and CS. These findings suggest that both age and environmental oxidant exposure affect pathways related to lung AT homeostasis and do so in a way that favors declines in lung AT. However, given the approach taken, the effects cannot be traced to changes in these pathways or AT content in any specific lung associated cell type and thus highlight the need for further follow-up studies looking at specific lung associated cell types.

  7. "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

  8. 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.

  9. 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

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

    PubMed

    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

    2011-12-01

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

    PubMed

    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

    2011-12-01

    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.

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. Reactive Transport Modeling of the Yucca Mountain Site, Nevada

    SciTech Connect

    G. Bodvarsson

    2004-04-20

    The Yucca Mountain site has a dry climate and deep water table, with the repository located in the middle of an unsaturated zone approximately 600 m thick. Radionuclide transport processes from the repository to the water table are sensitive to the unsaturated zone flow field, as well as to sorption, matrix diffusion, radioactive decay, and colloid transport mechanisms. The unsaturated zone flow and transport models are calibrated against both physical and chemical data, including pneumatic pressure, liquid saturation, water potential, temperature, chloride, and calcite. The transport model predictions are further compared with testing specific to unsaturated zone transport: at Alcove 1 in the Exploratory Studies Facility (ESF), at Alcove 8 and Niche 3 of the ESF, and at the Busted Butte site. The models are applied to predict the breakthroughs at the water table for nonsorbing and sorbing radionuclides, with faults shown as the important paths for radionuclide transport. Daughter products of some important radionuclides, such as {sup 239}Pu and {sup 241}Am, have faster transport than the parents and must be considered in the unsaturated zone transport model. Colloid transport is significantly affected by colloid size, but only negligibly affected by lunetic declogging (reverse filtering) mechanisms. Unsaturated zone model uncertainties are discussed, including the sensitivity of breakthrough to the active fracture model parameter, as an example of uncertainties related to detailed flow characteristics and fracture-matrix interaction. It is expected that additional benefits from the unsaturated zone barrier for transport can be achieved by full implementation of the shadow zone concept immediately below the radionuclide release points in the waste emplacement drifts.

  20. 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.

  1. 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.

  2. Microbiological Transformations of Radionuclides in the Subsurface

    SciTech Connect

    Marshall, Matthew J.; Beliaev, Alex S.; Fredrickson, Jim K.

    2010-01-04

    Microorganisms are ubiquitous in subsurface environments although their populations sizes and metabolic activities can vary considerably depending on energy and nutrient inputs. As a result of their metabolic activities and the chemical properties of their cell surfaces and the exopolymers they produce, microorganisms can directly or indirectly facilitate the biotransformation of radionuclides, thus altering their solubility and overall fate and transport in the environment. Although biosorption to cell surfaces and exopolymers can be an important factor modifying the solubility of some radionuclides under specific conditions, oxidation state is often considered the single most important factor controlling their speciation and, therefore, environmental behavior.

  3. 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)

  4. Solid-state fermentation in rotating drum bioreactors: operating variables affect performance through their effects on transport phenomena.

    PubMed

    Stuart, D M; Mitchell, D A; Johns, M R; Litster, J D

    1999-05-20

    Aspergillus oryzae ACM 4996 was grown on an artificial gel-based substrate and on steamed wheat bran during solid-state fermentations in 18.7 L rotating drum bioreactors. For gel fermentations fungal growth decreased as rotational speed increased, presumably due to increased shear. For wheat bran fermentations fungal growth improved under agitated compared to static culture conditions, due to superior heat and mass transfer. We conclude that the effects of operational variables on the performance of SSF bioreactors are mediated by their effects on transport phenomena such as mixing, shear, heat transfer, and mass transfer within the substrate bed. In addition, the substrate characteristics affect the need for and the rates of these transport processes. Different transport phenomena may be rate limiting with different substrates. This work improves understanding of the effects of bioreactor operation on SSF performance. PMID:10099618

  5. 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.

  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. 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

  8. A free database of radionuclide voxel S values for the dosimetry of nonuniform activity distributions.

    PubMed

    Lanconelli, N; Pacilio, M; Lo Meo, S; Botta, F; Di Dia, A; Aroche, A Torres; Pérez, M A Coca; Cremonesi, M

    2012-01-21

    The increasing availability of SPECT/CT devices with advanced technology offers the opportunity for the accurate assessment of the radiation dose to the biological target volume during radionuclide therapy. Voxel dosimetry can be performed employing direct Monte Carlo radiation transport simulations, based on both morphological and functional images of the patient. On the other hand, for voxel dosimetry calculations the voxel S value method can be considered an easier approach than patient-specific Monte Carlo simulations, ensuring a good dosimetric accuracy at least for anatomic regions which are characterized by uniform density tissue. However, this approach has been limited because of the lack of tabulated S values for different voxel dimensions and radionuclides. The aim of this work is to provide a free dataset of values which can be used for voxel dosimetry in targeted radionuclide studies. Seven different radionuclides (89Sr, 90Y, 131I, 153Sm, 177Lu, 186Re, 188Re), and 13 different voxel sizes (2.21, 2.33, 2.4, 3, 3.59, 3.9, 4, 4.42, 4.8, 5, 6, 6.8 and 9.28 mm) are considered. Voxel S values are calculated performing simulations of monochromatic photon and electron sources in two different homogeneous tissues (soft tissue and bone) with DOSXYZnrc code, and weighting the contributions on the basis of the radionuclide emission spectra. The outcomes are validated by comparison with Monte Carlo simulations obtained with other codes (PENELOPE and MCNP4c) performing direct simulation of the radionuclide emission spectra. The differences among the different Monte Carlo codes are of the order of a few per cent when considering the source voxel and the bremsstrahlung tail, whereas the highest differences are observed at a distance close to the maximum continuous slowing down approximation range of electrons. These discrepancies would negligibly affect dosimetric assessments. The dataset of voxel S values can be freely downloaded from the website www.medphys.it.

  9. A free database of radionuclide voxel S values for the dosimetry of nonuniform activity distributions

    NASA Astrophysics Data System (ADS)

    Lanconelli, N.; Pacilio, M.; Lo Meo, S.; Botta, F.; Di Dia, A.; Torres Aroche, L. A.; Coca Pérez, M. A.; Cremonesi, M.

    2012-01-01

    The increasing availability of SPECT/CT devices with advanced technology offers the opportunity for the accurate assessment of the radiation dose to the biological target volume during radionuclide therapy. Voxel dosimetry can be performed employing direct Monte Carlo radiation transport simulations, based on both morphological and functional images of the patient. On the other hand, for voxel dosimetry calculations the voxel S value method can be considered an easier approach than patient-specific Monte Carlo simulations, ensuring a good dosimetric accuracy at least for anatomic regions which are characterized by uniform density tissue. However, this approach has been limited because of the lack of tabulated S values for different voxel dimensions and radionuclides. The aim of this work is to provide a free dataset of values which can be used for voxel dosimetry in targeted radionuclide studies. Seven different radionuclides (89Sr, 90Y, 131I, 153Sm, 177Lu, 186Re, 188Re), and 13 different voxel sizes (2.21, 2.33, 2.4, 3, 3.59, 3.9, 4, 4.42, 4.8, 5, 6, 6.8 and 9.28 mm) are considered. Voxel S values are calculated performing simulations of monochromatic photon and electron sources in two different homogeneous tissues (soft tissue and bone) with DOSXYZnrc code, and weighting the contributions on the basis of the radionuclide emission spectra. The outcomes are validated by comparison with Monte Carlo simulations obtained with other codes (PENELOPE and MCNP4c) performing direct simulation of the radionuclide emission spectra. The differences among the different Monte Carlo codes are of the order of a few per cent when considering the source voxel and the bremsstrahlung tail, whereas the highest differences are observed at a distance close to the maximum continuous slowing down approximation range of electrons. These discrepancies would negligibly affect dosimetric assessments. The dataset of voxel S values can be freely downloaded from the website www.medphys.it.

  10. 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.

  11. 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.

  12. 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.

  13. Perturbation of nucleo-cytoplasmic transport affects size of nucleus and nucleolus in human cells.

    PubMed

    Ganguly, Abira; Bhattacharjee, Chumki; Bhave, Madhura; Kailaje, Vaishali; Jain, Bhawik K; Sengupta, Isha; Rangarajan, Annapoorni; Bhattacharyya, Dibyendu

    2016-03-01

    Size regulation of human cell nucleus and nucleolus are poorly understood subjects. 3D reconstruction of live image shows that the karyoplasmic ratio (KR) increases by 30-80% in transformed cell lines compared to their immortalized counterpart. The attenuation of nucleo-cytoplasmic transport causes the KR value to increase by 30-50% in immortalized cell lines. Nucleolus volumes are significantly increased in transformed cell lines and the attenuation of nucleo-cytoplasmic transport causes a significant increase in the nucleolus volume of immortalized cell lines. A cytosol and nuclear fraction swapping experiment emphasizes the potential role of unknown cytosolic factors in nuclear and nucleolar size regulation.

  14. 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.

  15. 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.

  16. 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...

  17. 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...

  18. Nutrient transport in human annulus fibrosus is affected by compressive strain and anisotropy.

    PubMed

    Jackson, Alicia R; Yuan, Tai-Yi; Huang, Chun-Yuh; Brown, Mark D; Gu, Wei Yong

    2012-12-01

    The avascular intervertebral disc (IVD) receives nutrition via transport from surrounding vasculature; poor nutrition is believed to be a main cause of disc degeneration. In this study, we investigated the effects of mechanical deformation and anisotropy on the transport of two important nutrients--oxygen and glucose--in human annulus fibrosus (AF). The diffusivities of oxygen and glucose were measured under three levels of uniaxial confined compression--0, 10, and 20%--and in three directions--axial, circumferential, and radial. The glucose partition coefficient was also measured at three compression levels. Results for glucose and oxygen diffusivity in AF ranged from 4.46 × 10(-7) to 9.77 × 10(-6) cm(2)/s and were comparable to previous studies; the glucose partition coefficient ranged from 0.71 to 0.82 and was also similar to previous results. Transport properties were found to decrease with increasing deformation, likely caused by fluid exudation during tissue compression and reduction in pore size. Furthermore, diffusivity in the radial direction was lower than in the axial or circumferential directions, indicating that nutrient transport in human AF is anisotropic. This behavior is likely a consequence of the layered structure and unique collagen architecture of AF tissue. These findings are important for better understanding nutritional supply in IVD and related disc degeneration.

  19. [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. PMID:17598993

  20. 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, ...

  1. 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.

  2. [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.

  3. 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.

  4. 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.

  5. 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. PMID:26922564

  6. How Do Hydrodynamic Instabilities Affect 3D Transport in Geophysical Vortices?

    NASA Astrophysics Data System (ADS)

    Wang, P.; Ozgokmen, T. M.

    2014-12-01

    Understanding three-dimensional (3D) transport in ocean eddies is important for processes at a variety of scales, ranging from plankton production to climate variability. It is well known that geophysical vortices are subject to various hydrodynamic instabilities. Yet the influence of these instabilities on 3D material transport in vortex systems is not well investigated. Focusing on barotropic, inertial and 3D instabilities, we analyze these instabilities with normal-mode method, and reproduce their characteristics via highly-resolved numerical simulations using a spectral element Navier-Stokes solver. By comparing the simulation results of stable and unstable vortices, we investigate the joint impacts of instabilities on 3D transport through three major aspects: (i) energy transfer, (ii) overturning transport of the secondary circulation, and (iii) rates of vertical exchange and mixing. It is found that instabilities can enhance local nonlinear interactions and cause the kinetic energy wavenumber spectrum to have slopes between the conventional -5/3 and -3 at inertial ranges. The cascade of a new quantity is proposed to explain these non-conventional slopes. One of our main results is the discovery of material exchange between the central vortex and satellite vortices through 3D pathways, called funnels. These funnels modify the concept of elliptic regions that can trap material when confined to 2D dynamics. Thus, we show that a family of vortices, created by the hydrodynamic instabilities of the initially unstable vortex, can still continue to operate in unity in order to complete the 3D transport in these systems. We also show that flow instabilities can double the magnitude of vertical velocity, increase the rate of vertical exchange by an order of magnitude and enhance mixing rate more than 100%.

  7. 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.

  8. 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.

  9. Sorption and transport of uranium on Hematite milestone

    SciTech Connect

    Viani, B., LLNL

    1998-02-03

    Transport of radionuclides that escape failed waste packages (WP) may be significantly affected by interaction with the alteration products derived from the WP components and other construction materials. The interaction of WP`s and other ferrous metal materials with groundwater prior to failure is expected to result in the formation of iron oxides (Viani, 1996). These phases are expected to significantly retard U and Np, radionuclides that are not strongly retarded by the repository horizon and the surrounding rocks (Meijer, 1990). Because sorption of radionuclides onto iron oxides is strongly dependent on fluid composition (e.g.; pH and dissolved carbon), mechanistic models that capture the detailed chemistry and physics that control transport must validated before credible predictions of the effects of WP alteration products can be made, and before limits on radionuclide transport through the engineered barrier system (EBS) can be placed. Reactive transport models that couple sorption models to fluid flow models are also required to assess the ability of more simplistic PA models to capture the essential features of the transport process. This letter report presents results of sorption and transport experiments that are designed to obtain parameters to be used in coupled models and to test the ability of these models to predict transport.

  10. Drug membrane transporters and CYP3A4 are affected by hypericin, hyperforin or aristoforin in colon adenocarcinoma cells.

    PubMed

    Šemeláková, M; Jendželovský, R; Fedoročko, P

    2016-07-01

    Our previous results have shown that the combination of hypericin-mediated photodynamic therapy (HY-PDT) at sub-optimal dose with hyperforin (HP) (compounds of Hypericum sp.), or its stable derivative aristoforin (AR) stimulates generation of reactive oxygen species (ROS) leading to antitumour activity. This enhanced oxidative stress evoked the need for an explanation for HY accumulation in colon cancer cells pretreated with HP or AR. Generally, the therapeutic efficacy of chemotherapeutics is limited by drug resistance related to the overexpression of drug efflux transporters in tumour cells. Therefore, the impact of non-activated hypericin (HY), HY-PDT, HP and AR on cell membrane transporter systems (Multidrug resistance-associated protein 1-MRP1/ABCC1, Multidrug resistance-associated protein 2-MRP2/ABCC2, Breast cancer resistance protein - BCRP/ABCG2, P-glycoprotein-P-gp/ABCC1) and cytochrome P450 3A4 (CYP3A4) was evaluated. The different effects of the three compounds on their expression, protein level and activity was determined under specific PDT light (T0+, T6+) or dark conditions (T0- T6-). We found that HP or AR treatment affected the protein levels of MRP2 and P-gp, whereas HP decreased MRP2 and P-gp expression mostly in the T0+ and T6+ conditions, while AR decreased MRP2 in T0- and T6+. Moreover, HY-PDT treatment induced the expression of MRP1. Our data demonstrate that HP or AR treatment in light or dark PDT conditions had an inhibitory effect on the activity of individual membrane transport proteins and significantly decreased CYP3A4 activity in HT-29 cells. We found that HP or AR significantly affected intracellular accumulation of HY in HT-29 colon adenocarcinoma cells. These results suggest that HY, HP and AR might affect the efficiency of anti-cancer drugs, through interaction with membrane transporters and CYP3A4. PMID:27261575

  11. Increased phloem transport of S-methylmethionine positively affects sulfur and nitrogen metabolism and seed development in pea plants.

    PubMed

    Tan, Qiumin; Zhang, Lizhi; Grant, Jan; Cooper, Pauline; Tegeder, Mechthild

    2010-12-01

    Seeds of grain legumes are important energy and food sources for humans and animals. However, the yield and quality of legume seeds are limited by the amount of sulfur (S) partitioned to the seeds. The amino acid S-methylmethionine (SMM), a methionine derivative, has been proposed to be an important long-distance transport form of reduced S, and we analyzed whether SMM phloem loading and source-sink translocation are important for the metabolism and growth of pea (Pisum sativum) plants. Transgenic plants were produced in which the expression of a yeast SMM transporter, S-Methylmethionine Permease1 (MMP1, YLL061W), was targeted to the phloem and seeds. Phloem exudate analysis showed that concentrations of SMM are elevated in MMP1 plants, suggesting increased phloem loading. Furthermore, expression studies of genes involved in S transport and metabolism in source organs, as well as xylem sap analyses, support that S uptake and assimilation are positively affected in MMP1 roots. Concomitantly, nitrogen (N) assimilation in root and leaf and xylem amino acid profiles were changed, resulting in increased phloem loading of amino acids. When investigating the effects of increased S and N phloem transport on seed metabolism, we found that protein levels were improved in MMP1 seeds. In addition, changes in SMM phloem loading affected plant growth and seed number, leading to an overall increase in seed S, N, and protein content in MMP1 plants. Together, these results suggest that phloem loading and source-sink partitioning of SMM are important for plant S and N metabolism and transport as well as seed set.

  12. Transport of root-derived CO2 via the transpiration stream affects aboveground tree physiology

    NASA Astrophysics Data System (ADS)

    Bloemen, J.; McGuire, M. A.; Aubrey, D. P.; Teskey, R. O.; Steppe, K.

    2012-04-01

    Recent research on soil CO2 efflux has shown that belowground autotrophic respiration is largely underestimated using classical net CO2 flux measurements. Aubrey & Teskey (2009) found that in forest ecosystems a substantial portion of the CO2 released from root respiration remained within the root system and was transported aboveground in the stem via the transpiration stream. The magnitude of this upward movement of CO2 from belowground tissues suggested important implications for how we measure above- and belowground respiration. If a considerable fraction of root-respired CO2 is transported aboveground, where it might be fixed in woody and leaf tissues, then we are routinely underestimating the amount of C needed to sustain belowground tissues. In this study, we infused 13C labeled water into the base of field-grown poplar trees as a surrogate for root-respired CO2 to investigate the possible role of root-derived CO2 as substrate for carbon fixation. The label was transported upwards from the base of the tree toward the top. During its ascent, the 13C label was removed from the transpiration stream and fixed by chlorophyll-containing woody (young bark and xylem) and leaf (petiole) tissues. Moreover, based on 13C analysis of gas samples, we observed that up to 88 ± 0.10 % of the label applied was lost to the atmosphere by stem and branch efflux higher in the trees. Given that one-half of root-respired CO2 may follow this internal flux pathway (Aubrey & Teskey, 2009), we calculated that up to 44% of the root-respired CO2 could diffuse to the atmosphere once transported to the stem and branches. Thus, a large portion of CO2 that diffuses out of aboveground tissues may actually result from root respiration. Our results show that CO2 originating belowground can be transported internally to aboveground parts of trees, where it will have an important impact on tree physiology. Internal transport of CO2 indicates that the gas exchange approach to estimating above- and

  13. 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. PMID:26147312

  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. 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.

  17. Growth rate and nutrient limitation affect the transport of Rhodococcus sp. strain DN22 through sand.

    PubMed

    Priestley, James T; Coleman, Nicholas V; Duxbury, Trevor

    2006-12-01

    Rhodococcus strain DN22 grows on the nitramine explosive RDX as a sole nitrogen source, and is potentially useful for bioremediation of explosives-contaminated soil. In order for strain DN22 to be effectively applied in situ, inoculum cells must reach zones of RDX contamination via passive transport, a process that is difficult to predict at field-scale. We examined the effect of growth conditions on the transport of DN22 cells through sand columns, using chemostat-grown cultures. Strain DN22 formed smaller coccoid cells at low dilution rate (0.02 h(-1)) and larger rods at high dilution rate (0.1 h(-1)). Under all nutrient limitation conditions studied, smaller cells grown at low dilution rate were retained more strongly by sand columns than larger cells grown at high dilution rate. At a dilution rate of 0.05, cells from nitrate-limited cultures were retained more strongly than cells from RDX-limited or succinate-limited cultures. Breakthrough concentrations (C/C (0)) from sand columns ranged from 0.04 (nitrate-limited, D=0.02 h(-1)) to 0.98 (succinate-limited, D=0.1 h(-1)). The observed strong effect of culture conditions on transport of DN22 cells emphasizes the importance of physiology studies in guiding the development of bioremediation technologies.

  18. [How do transport and metabolism affect the biological effects of polycyclic aromatic hydrocarbons?].

    PubMed

    Bekki, Kanae; Toriba, Akira; Tang, Ning; Kameda, Takayuki; Takigami, Hidetaka; Suzuki, Go; Hayakawa, Kazuichi

    2012-01-01

    Polycyclic aromatic hydrocarbons (PAHs), some of which are carcinogenic/mutagenic, are generated by combustion of fossil fuels and also released through tanker or oilfield accident to cause a large scale environmental pollution. PAHs concentration in China is especially high in East Asia because of many kinds of generation sources such as coal heating systems, vehicles and factories without exhaust gas/particulate treatment systems. So, the atmospheric pollution caused by PAHs in China has been seriously concerned from the view point of health effects. Like yellow sand and sulfur oxide, PAHs exhausted in China are also transported to Japan. Additionally, strongly mutagenic nitrated PAHs (NPAHs), estrogenic/antiestrogenic PAH hydroxides (PAHOHs) and reactive oxygen species-producing PAH quinones (PAHQs) are formed from PAHs by the chemical reaction during the transport. Furthermore these PAHOHs and PAHQs are produced by the metabolism in animal body. In the biological activities caused by the above PAH derivatives, the structure-activity relationship was observed. In this review, our recent results on the generation of PAH derivatives by atmospheric transport and metabolism are reported. Also, the existing condition of PAHs as atmospheric pollutants is considered.

  19. 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

  20. Deregulated Copper Transport Affects Arabidopsis Development Especially in the Absence of Environmental Cycles1[C][W

    PubMed Central

    Andrés-Colás, Nuria; Perea-García, Ana; Puig, Sergi; Peñarrubia, Lola

    2010-01-01

    Copper is an essential cofactor for key processes in plants, but it exerts harmful effects when in excess. Previous work has shown that the Arabidopsis (Arabidopsis thaliana) COPT1 high-affinity copper transport protein participates in copper uptake through plant root tips. Here, we show that COPT1 protein localizes to the plasma membrane of Arabidopsis cells and the phenotypic effects of transgenic plants overexpressing either COPT1 or COPT3, the latter being another high-affinity copper transport protein family member. Both transgenic lines exhibit increased endogenous copper levels and are sensitive to the copper in the growth medium. Additional phenotypes include decreased hypocotyl growth in red light and differentially affected flowering times depending on the photoperiod. Furthermore, in the absence of environmental cycles, such as light and temperature, the survival of plants overexpressing COPT1 or COPT3 is compromised. Consistent with altered circadian rhythms, the expression of the nuclear circadian clock genes CIRCADIAN CLOCK-ASSOCIATED1 (CCA1) and LATE ELONGATED HYPOCOTYL (LHY) is substantially reduced in either COPT1- or COPT3-overexpressing plants. Copper affects the amplitude and the phase, but not the period, of the CCA1 and LHY oscillations in wild-type plants. Copper also drives a reduction in the expression of circadian clock output genes. These results reveal that the spatiotemporal control of copper transport is a key aspect of metal homeostasis that is required for Arabidopsis fitness, especially in the absence of environmental cues. PMID:20335405

  1. 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.

  2. Peptide receptor radionuclide therapy of neuroendocrine tumours.

    PubMed

    Brabander, Tessa; Teunissen, Jaap J M; Van Eijck, Casper H J; Franssen, Gaston J H; Feelders, Richard A; de Herder, Wouter W; Kwekkeboom, Dik J

    2016-01-01

    In the past decades, the number of neuroendocrine tumours that are detected is increasing. A relative new and promising therapy for patients with metastasised or inoperable disease is peptide receptor radionuclide therapy (PRRT). This therapy involves an infusion of somatostatin analogues linked to radionuclides like Yttrium-90 or Lutetium-177. Objective response rates are reported in 15-35%. Response rates may vary between type of tumour and radionuclide. Besides the objective response rate, overall survival and progression free survival increase significantly. Also, the quality of life improves as well. Serious side-affects are rare. PRRT is usually well tolerated, also in patients with extensive metastasised disease. Recent studies combined PRRT with other types of therapies. Unfortunately no randomised trials comparing these strategies are available. In the future, more research is needed to evaluate the best therapy combinations or sequence of therapies. PMID:26971847

  3. 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...

  4. A sucrose transporter-interacting protein disulphide isomerase affects redox homeostasis and links sucrose partitioning with abiotic stress tolerance.

    PubMed

    Eggert, Erik; Obata, Toshihiro; Gerstenberger, Anne; Gier, Konstanze; Brandt, Tobias; Fernie, Alisdair R; Schulze, Waltraud; Kühn, Christina

    2016-06-01

    Sucrose accumulation in leaves in response to various abiotic stresses suggests a specific role of this disaccharide for stress tolerance and adaptation. The high-affinity transporter StSUT1 undergoes substrate-induced endocytosis presenting the question as to whether altered sucrose accumulation in leaves in response to stresses is also related to enhanced endocytosis or altered activity of the sucrose transporter. StSUT1 is known to interact with several stress-inducible proteins; here we investigated whether one of the interacting candidates, StPDI1, affects its subcellular localization in response to stress: StPDI1 expression is induced by ER-stress and salt. Both proteins, StSUT1 and StPDI1, were found in the detergent resistant membrane (DRM) fraction, and this might affect internalization. Knockdown of StPDI1 expression severely affects abiotic stress tolerance of transgenic potato plants. Analysis of these plants does not reveal modified subcellular localization or endocytosis of StSUT1, but rather a disturbed redox homeostasis, reduced detoxification of reactive oxygen species and effects on primary metabolism. Parallel observations with other StSUT1-interacting proteins are discussed. The redox status in leaves seems to be linked to the sugar status in response to various stress stimuli and to play a role in stress tolerance. PMID:26670204

  5. 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

  6. 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.

  7. 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.

  8. Thermal and Colloid Related Processes and Uncertainty Affecting Plutonium Transport in NTS Groundwater

    NASA Astrophysics Data System (ADS)

    Wolfsberg, A. V.; Lu, G.; Glascoe, L. G.; McGraw, M. M.; Olson, A. J.

    2001-12-01

    Field observations of plutonium migration away from the BENHAM underground nuclear test at the Nevada Test Site (NTS) have raised concerns regarding how much of the post-test inventory may actually be mobile and how far it can be expected to move. There are two key issues associated with the field observations. First, the highest concentration of plutonium was found in a well sampling a welded tuff aquifer more than 500 m above the BENHAM emplacement location. Second, plutonium is generally believed to be immobile in groundwater as a result of reactions with immobile minerals. To address the first issue, we simulate non-isothermal flow and transport in the collapsed cavity/chimney system that forms following an underground explosion. With this model, we demonstrate the feasibility of thermally induced, vertical migration of colloids to the upper aquifer in which plutonium was detected. The second component addresses the migration of plutonium in the fractured volcanic host rock between the source and the observation wells. The reactive transport model includes solute-colloid reactions, solute reactions with fracture coating minerals, diffusion of solutes from fractures into matrix material, and solute reactions with matrix minerals. With this model, we demonstrate that very low concentrations of plutonium at the observation well are feasible when colloid-facilitated solute transport processes are considered. However, this study also highlights a very large range in model result uncertainty resulting from uncertainty in aquifer properties and transport parameters. Uncertain parameters having the greatest impact on prediction uncertainty include fracture mineral reactive surface area, groundwater oxidation/reduction potential, reactive site concentration on colloids, kinetic rates of Pu-colloid reactions, and fracture porosity. This presentation will provide comparisons of the net impact of reducing uncertainty for several primary parameters. This work was performed

  9. 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. PMID:25916229

  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. 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.

  12. 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

  13. 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

  14. Pseudomonas fluorescens adhesion and transport through porous media are affected by lipopolysaccharide composition.

    PubMed Central

    Williams, V; Fletcher, M

    1996-01-01

    The objectives of this work were (i) to use transposon mutagenesis to produce mutants of Pseudomonas fluorescens that were altered in adhesion ability and transport through porous media and (ii) to identify the alterations in surface characteristics that were responsible for the changes in attachment. Mutants of P. fluorescens were generated with TnphoA, which enabled identification of mutants that were altered in surface proteins. Transposon mutants were screened for alterations in adhesion ability by attachment assays on hydrophobic polystyrene and water-wettable polystyrene. Four TnphoA mutants with increased adhesion to the hydrophobic surface and decreased adhesion to the water-wettable surface were obtained. Transport of the strains through porous media was evaluated by passing suspensions of each mutant and the parent through columns containing quartz sand and determining the number of cells retained in the columns. The mutants all demonstrated increased adhesion and retention in the columns. Southern analysis demonstrated two types of mutants with separate transposon insertion sites. Polyacrylamide gel electrophoresis of the strains demonstrated that the O antigen on the lipopolysaccharide was either attenuated or absent. Lack of this polysaccharide, and the consequent increased exposure of the lipid moiety of the lipopolysaccharide, is probably responsible for the increase in adhesion to the hydrophobic substrata and retention in the sand column. This work combined with previous studies of attachment of P. fluorescens demonstrates that more than one type of polymer can mediate the adhesion of this organism to nonbiological surfaces. PMID:8572686

  15. 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.

  16. 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.

  17. 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.

  18. Transport and deposition of radionuclides after the Fukushima nuclear accident: international model inter-comparison in the framework of a WMO Task Team

    NASA Astrophysics Data System (ADS)

    Wotawa, Gerhard; Draxler, Roland; Arnold, Delia; Galmarini, Stefano; Hort, Matthew; Jones, Andrew; Leadbetter, Susan; Malo, Alain; Maurer, Christian; Rolph, Glenn; Saito, Kazuo; Servranckx, Rene; Shimbori, Toshiki; Solazzo, Efisio

    2013-04-01

    In the framework of a Task Team set up after the Fukushima accident sponsored by WMO, the atmospheric transport and deposition models (ATDMs) FLEXPART (Austria), HYSPLIT (U.S.), MLDP0 (Canada), NAME (UK) and RATM (Japan) were inter-compared. These models are well-known and widely used for emergency response activities. As alternative model input data, JMA made available a Meso-Analysis with 5 km/ 3 hour resolution, and a radar/rain gauge precipitation analysis with 1 km and 30 minutes resolution. To allow maximum flexibility regarding the release rates of key nuclides, the computations were based on the concept of source-receptor matrices, in this connection also called transfer coefficient matrices (TCM). The matrices are calculated every 3 hours after 11 March 2011 00 UTC, based on unit emissions, and thus can be overlaid with any present and future release scenario that becomes established. As computational species, the model considered tracers, depositing gases and depositing aerosols, allowing accounting for the range of substances emitted during a nuclear accident. The model comparison was based on observed deposition patterns of Cesium-137 in the Fukushima province as collected by MEXT/USDOE shortly after the accident, and a few available in situ stations measuring radioactive isotopes. To perform a statistical comparison, established parameters like correlation coefficient (r), fractional bias (FB) and figure of merit in space (FMS) were used. A further ensemble analysis was performed to determine what subset of model results out of all available would provide non-redundant information and thus is optimal to describe the transport and deposition during the accident. The investigation showed (i) that a TCM-based calculation approach has a lot of merits due to its flexibility, (ii) that models tended to perform better if they were run in improved resolution or directly with the Japanese Meso-analysis, (iii) that the model results depend on the selection of

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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

    2016-09-01

    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.

  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. 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.

  7. 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. PMID:25999514

  8. Physical factors affecting the transport and fate of colloids in saturated porous media

    NASA Astrophysics Data System (ADS)

    Bradford, Scott A.; Yates, Scott R.; Bettahar, Mehdi; Simunek, Jirka

    2002-12-01

    Saturated soil column experiments were conducted to explore the influence of colloid size and soil grain size distribution characteristics on the transport and fate of colloid particles in saturated porous media. Stable monodispersed colloids and porous media that are negatively charged were employed in these studies. Effluent colloid concentration curves and the final spatial distribution of retained colloids by the porous media were found to be highly dependent on the colloid size and soil grain size distribution. Relative peak effluent concentrations decreased and surface mass removal by the soil increased when the colloid size increased and the soil median grain size decreased. These observations were attributed to increased straining of the colloids; i.e., blocked pores act as dead ends for the colloids. When the colloid size is small relative to the soil pore sizes, straining becomes a less significant mechanism of colloid removal and attachment becomes more important. Mathematical modeling of the colloid transport experiments using traditional colloid attachment theory was conducted to highlight differences in colloid attachment and straining behavior and to identify parameter ranges that are applicable for attachment models. Simulated colloid effluent curves using fitted first-order attachment and detachment parameters were able to describe much of the effluent concentration data. The model was, however, less adequate at describing systems which exhibited a gradual approach to the peak effluent concentration and the spatial distribution of colloids when significant mass was retained in the soil. Current colloid filtration theory did not adequately predict the fitted first-order attachment coefficients, presumably due to straining in these systems.

  9. Amphetamine and methamphetamine differentially affect dopamine transporters in vitro and in vivo.

    PubMed

    Goodwin, J Shawn; Larson, Gaynor A; Swant, Jarod; Sen, Namita; Javitch, Jonathan A; Zahniser, Nancy R; De Felice, Louis J; Khoshbouei, Habibeh

    2009-01-30

    The psychostimulants d-amphetamine (AMPH) and methamphetamine (METH) release excess dopamine (DA) into the synaptic clefts of dopaminergic neurons. Abnormal DA release is thought to occur by reverse transport through the DA transporter (DAT), and it is believed to underlie the severe behavioral effects of these drugs. Here we compare structurally similar AMPH and METH on DAT function in a heterologous expression system and in an animal model. In the in vitro expression system, DAT-mediated whole-cell currents were greater for METH stimulation than for AMPH. At the same voltage and concentration, METH released five times more DA than AMPH and did so at physiological membrane potentials. At maximally effective concentrations, METH released twice as much [Ca(2+)](i) from internal stores compared with AMPH. [Ca(2+)](i) responses to both drugs were independent of membrane voltage but inhibited by DAT antagonists. Intact phosphorylation sites in the N-terminal domain of DAT were required for the AMPH- and METH-induced increase in [Ca(2+)](i) and for the enhanced effects of METH on [Ca(2+)](i) elevation. Calmodulin-dependent protein kinase II and protein kinase C inhibitors alone or in combination also blocked AMPH- or METH-induced Ca(2+) responses. Finally, in the rat nucleus accumbens, in vivo voltammetry showed that systemic application of METH inhibited DAT-mediated DA clearance more efficiently than AMPH, resulting in excess external DA. Together these data demonstrate that METH has a stronger effect on DAT-mediated cell physiology than AMPH, which may contribute to the euphoric and addictive properties of METH compared with AMPH.

  10. Weaning marginally affects glucose transporter (GLUT4) expression in calf muscles and adipose tissues.

    PubMed

    Hocquette, J F; Castiglia-Delavaud, C; Graulet, B; Ferré, P; Picard, B; Vermorel, M

    1997-08-01

    The nutritional regulation of glucose transporter GLUT4 was studied in eight muscles and four adipose tissues from two groups of preruminant (PR) or ruminant (R) calves of similar age (170 d), empty body weight (194 kg) at slaughter, and level of net energy intake from birth onwards. Isocitrate dehydrogenase (EC 1.1.1.41) activity in muscles was not different between PR and R except in masseter muscle from the cheek (+71% in R; P < 0.003), which becomes almost constantly active at weaning for food chewing. Basal and maximally-insulin-stimulated glucose transport rate (GTR) per g tissue wet weight in rectus abdominis muscle were significantly higher in R calves (+31 and 41% respectively; P < 0.05). GLUT4 protein contents did not differ in muscles from PR and R except in masseter (+74% in R; P < 0.05) indicating that the increased GTR in rectus abdominis cannot be accounted for by an enhanced GLUT4 expression. GLUT4 mRNA levels did not differ between the two groups of animals in all muscles suggesting a regulation of GLUT4 at the protein level in masseter. GLUT4 number expressed on a per cell basis was lower in adipose tissue from R calves (-39%; P < 0.05) and higher in internal than in peripheral adipose tissues. In summary, the regulation of GLUT4 in calves at weaning differs markedly from that previously described in rodents (for review, see Girard et al. 1992). Furthermore, significant inter-individual variations were shown for metabolic activities in muscle and for biochemical variables in adipose tissue.

  11. 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

  12. 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.

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

    SciTech Connect

    James Saiers

    2006-06-28

    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 colloid-associated 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.

  14. Radionuclide migration laboratory studies for validation of batch sorption data

    SciTech Connect

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

    1991-12-31

    Advective and diffusive migration experiments (within the Dynamic Transport Column Experiments and Diffusion Studies of the Yucca Mountain Site Characterization Project) involve utilizing crushed material, intact, and fractured tuff in order to test and improve (if necessary) transport models by experimentally observing the migration of sorbing and non-sorbing radionuclides on a laboratory scale. Performing a validation of the sorption data obtained with batch techniques (within the Batch Sorption Study) is an integral part of the mission of the Dynamic Transport Column Experiments and Diffusion Studies. In this paper the work scope of the radionuclide migration laboratory experiments (as they apply to validation of batch sorption data) is reviewed.

  15. 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

  16. Chemical form of selenium affects its uptake, transport, and glutathione peroxidase activity in the human intestinal Caco-2 cell model.

    PubMed

    Zeng, Huawei; Jackson, Matthew I; Cheng, Wen-Hsing; Combs, Gerald F

    2011-11-01

    Determining the effect of selenium (Se) chemical form on uptake, transport, and glutathione peroxidase activity in human intestinal cells is critical to assess Se bioavailability at nutritional doses. In this study, we found that two sources of L-selenomethionine (SeMet) and Se-enriched yeast each increased intracellular Se content more effectively than selenite or methylselenocysteine (SeMSC) in the human intestinal Caco-2 cell model. Interestingly, SeMSC, SeMet, and digested Se-enriched yeast were transported at comparable efficacy from the apical to basolateral sides, each being about 3-fold that of selenite. In addition, these forms of Se, whether before or after traversing from apical side to basolateral side, did not change the potential to support glutathione peroxidase (GPx) activity. Although selenoprotein P has been postulated to be a key Se transport protein, its intracellular expression did not differ when selenite, SeMSC, SeMet, or digested Se-enriched yeast was added to serum-contained media. Taken together, our data show, for the first time, that the chemical form of Se at nutritional doses can affect the absorptive (apical to basolateral side) efficacy and retention of Se by intestinal cells; but that, these effects are not directly correlated to the potential to support GPx activity.

  17. Beyond affect: A role for genetic variation of the serotonin transporter in neural activation during a cognitive attention task

    PubMed Central

    Canli, Turhan; Omura, Kazufumi; Haas, Brian W.; Fallgatter, Andreas; Constable, R. Todd; Lesch, Klaus Peter

    2005-01-01

    Prior work has highlighted the role of genetic variation within the repetitive sequence in the transcriptional control region of the serotonin (5-HT) transporter gene (5-HTT, SLC6A4) in modulating amygdala and prefrontal activation to negative emotional stimuli. However, these studies have not explicitly tested the assumption that the control condition (neutral baseline) does not itself produce changes in activation as a function of 5-HTT genotype. Using a fixation baseline condition, we show that variation in 5-HTT genotype is associated with differential activation to negative, positive, and neutral stimuli in limbic, striatal, and cortical regions. We replicate earlier reports of increased amygdala activation to negative, relative to neutral, stimuli, but then show that these differences are driven by decreased activation to neutral stimuli, rather than increased activation to negative stimuli, in carriers of the 5-HTT short allele. Using high-resolution structural images and automated processes to test for brain volume and gray matter density, we further report significant differences, as a function of 5-HTT genotype, in frontal cortical regions, anterior cingulate, and cerebellum. These functional and structural differences suggest a much broader role for 5-HT transport efficiency in brain processes than previously thought. 5-HTT genotype affects neural systems controlling affective, cognitive, and motor processes. PMID:16093315

  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 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

  20. Physical oceanographic processes affecting larval transport around and through North Carolina inlets

    SciTech Connect

    Pietrafesa, L.J.; Janowitz, G.S.

    1985-01-01

    Atlantic Spot, Flounder, Croaker and Menhaden all spawn in shelf waters of North Carolina during late fall to early winter. The juveniles use estuaries such as Pamlico Sound and the Cape Fear River as nurseries during their first winter and spring. Previous studies of recruitment into the estuaries through barrier island inlets or estarine mouths assume that the pre and post metamorphosed larvae enter the estuaries at the bottom of the water column and move upstream thereafter. The mechanisms were presumed tidal. The Pamlico Sound has several inlets, Oregon, Hatteras and ocracroke, through which larvae can enter not only during flood stages of the tide but also in the presence of favorable oceanic to estuary sea level pressure gradients. The Cape Fear River has a strong semi-diurnal tidal flow both flood and ebb and also responds vigorously to one-sided divergences and convergences at its mouth. Flow, looking out of the mouth, is in at the left and out on the right. The conclusions are that, in addition to flooding tides, non-local forcing at the estuary mouths can effect transport of larval fish through the estuary mouths, throughout the entire water column.

  1. 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.

  2. How imperfect interfaces affect the nonlinear transport properties in composite nanomaterials

    NASA Astrophysics Data System (ADS)

    Pavanello, Fabio; Giordano, Stefano

    2013-04-01

    Nanomaterials composed of a population of particles dispersed in a matrix represent the building block for the next generation of several technologies: energy storage and conversion, thermal management, electronics, and photovoltaics. When interfaces between particles and matrix are imperfect, the size of the particles may strongly influence the effective linear and nonlinear response of the whole system. Here, we study these scale effects mainly focussing on the nonlinear transport behavior of composite structures. The theory is developed, in the framework of the electrical conductivity, for an arbitrary nonlinearity of the constituents; however, explicit results are discussed for Kerr-like nonlinear responses. Two kinds of imperfect interfaces are considered: the T-model and the Π-model, which represent a generalization of the classical schemes largely employed in literature, namely the low and the high conducting interface models. The dependence of the nonlinear effective properties on the size of the dispersed particles is explained through intrinsic length scales governing some universal scaling laws.

  3. 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.

  4. 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

    2016-01-01

    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 [(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. PMID:27601313

  5. The sucrose transporter SlSUT2 from tomato interacts with brassinosteroid functioning and affects arbuscular mycorrhiza formation.

    PubMed

    Bitterlich, Michael; Krügel, Undine; Boldt-Burisch, Katja; Franken, Philipp; Kühn, Christina

    2014-06-01

    Mycorrhizal plants benefit from the fungal partners by getting better access to soil nutrients. In exchange, the plant supplies carbohydrates to the fungus. The additional carbohydrate demand in mycorrhizal plants was shown to be balanced partially by higher CO2 assimilation and increased C metabolism in shoots and roots. In order to test the role of sucrose transport for fungal development in arbuscular mycorrhizal (AM) tomato, transgenic plants with down-regulated expression of three sucrose transporter genes were analysed. Plants that carried an antisense construct of SlSUT2 (SlSUT2as) repeatedly exhibited increased mycorrhizal colonization and the positive effect of plants to mycorrhiza was abolished. Grafting experiments between transgenic and wild-type rootstocks and scions indicated that mainly the root-specific function of SlSUT2 has an impact on colonization of tomato roots with the AM fungus. Localization of SISUT2 to the periarbuscular membrane indicates a role in back transport of sucrose from the periarbuscular matrix into the plant cell thereby affecting hyphal development. Screening of an expression library for SlSUT2-interacting proteins revealed interactions with candidates involved in brassinosteroid (BR) signaling or biosynthesis. Interaction of these candidates with SlSUT2 was confirmed by bimolecular fluorescence complementation. Tomato mutants defective in BR biosynthesis were analysed with respect to mycorrhizal symbiosis and showed indeed decreased mycorrhization. This finding suggests that BRs affect mycorrhizal infection and colonization. If the inhibitory effect of SlSUT2 on mycorrhizal growth involves components of BR synthesis and of the BR signaling pathway is discussed.

  6. 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.

  7. 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

  8. Sodium arsenite affects Na+ transport in the isolated skin of the toad Pleurodema thaul.

    PubMed

    Suwalsky, Mario; Rivera, Cecilia; Norris, Beryl; Cárdenas, Hernán

    2007-01-01

    Arsenic, applied as sodium arsenite (As(III)) to either inner or outer surfaces of the isolated toad skin, dose-dependently decreased the short-circuit current (Isc), potential difference (PD) and sodium conductance (G(Na)) in the concentration range 1-1000 microM, with effects often lasting over 3 h. Maximal inhibitory effect was over 90% with an IC(50) of about 34 microM. Applied during amiloride block, As(III) did not change this effect. However, an increase in electric parameters was noted during the initial 30 min in 22 experiments, indicating a possible translocation of cytosolic protein kinase C (PKC) to the membrane within 15 min, thus stimulating sodium transport; this is followed by a progressive inhibition of kinase activity. Comparative effects of amiloride (8 microM), As(III) (100 microM, outer surface) and noradrenaline (NA, 10 microM, inner surface) showed a significant increase in the stimulatory effect of NA on the electric parameters, which could be the result of arsenite clustering of cell surface receptors and activation of ensuing cellular signal transduction pathways. Ouabain 5 microM, followed by As(III) 100 microM, also stimulated the skin response to NA (10 microM), although the duration of the two phases of the response was markedly shortened. The exact mechanism is still in doubt: however, As(III) increases cerebral metabolites of NA and ouabain can increase NA efflux from tissue slices. The amiloride test, performed with As(III) in the outer surface, confirmed significant decrease in all the parameters: the driving force (E(Na)), sodium conductance (G(Na)), and importantly, shunt conductance (G(sh)), due to the known fact that arsenic inhibits gap junctional intercellular communication. PMID:17055342

  9. 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.

  10. 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. PMID:26617587

  11. 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

  12. ARF6-mediated endosomal transport of Telencephalin affects dendritic filopodia-to-spine maturation

    PubMed Central

    Raemaekers, Tim; Peric, Aleksandar; Baatsen, Pieter; Sannerud, Ragna; Declerck, Ilse; Baert, Veerle; Michiels, Christine; Annaert, Wim

    2012-01-01

    Dendritic filopodia are dynamic structures thought to be the precursors of spines during synapse development. Morphological maturation to spines is associated with the stabilization and strengthening of synapses, and can be altered in various neurological disorders. Telencephalin (TLN/intercellular adhesion molecule-5 (ICAM5)) localizes to dendritic filopodia, where it facilitates their formation/maintenance, thereby slowing spine morphogenesis. As spines are largely devoid of TLN, its exclusion from the filopodia surface appears to be required in this maturation process. Using HeLa cells and primary hippocampal neurons, we demonstrate that surface removal of TLN involves internalization events mediated by the small GTPase ADP-ribosylation factor 6 (ARF6), and its activator EFA6A. This endocytosis of TLN affects filopodia-to-spine transition, and requires Rac1-mediated dephosphorylation/release of actin-binding ERM proteins from TLN. At the somato-dendritic surface, TLN and EFA6A are confined to distinct, flotillin-positive membrane subdomains. The co-distribution of TLN with this lipid raft marker also persists during its endosomal targeting to CD63-positive late endosomes. This suggests a specific microenvironment facilitating ARF6-mediated mobilization of TLN that contributes to promotion of dendritic spine development. PMID:22781129

  13. 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

  14. 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

  15. 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

  16. 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.

  17. Research note: Postnatal development of electrolyte transport in calf rumen as affected by weaning time.

    PubMed

    Breves, G; Zitnan, R; Schröder, B; Winckler, C; Hagemeister, H; Failing, K; Voigt, J

    2002-10-01

    In a previous study we found a positive correlation between early weaning in calves and morphological parameters which were indicative of ruminal development, i.e. the length and width of the papillae. The objective of the present study was to determine to what extent this observation could be reflected by modulations of absorptive and secretory functions of the rumen mucosa. For this purpose the short-circuit currents (Isc) as a measure of electrogenic net ion fluxes and the transepithelial conductances (G(T)) as a measure of the overall tissue permeability were measured in vitro applying the Ussing-chamber technique. Simultaneously, the unidirectional flux rates of sodium and chloride across rumen wall epithelia were determined in the absence of electrochemical gradients. Under these conditions, significant positive net flux rates (Jnet) clearly indicate active mechanisms for electrolyte absorption. For the experiments 12 male Holstein calves 7 d of age were assigned to three groups of 4 animals each: milk group (I, slaughtered after 6 weeks of age), late weaning group (II, slaughtered after 9 weeks of age) and early weaning group (II, weaned after 6 weeks of age and slaughtered after 9 weeks of age). Whereas G(T) values remained unaffected by different age and feeding, Isc values were significantly affected by early weaning but were not influenced by age. Irrespective of weaning time active absorption of Na+ tended to be higher by about 60% in 9 weeks old animals. Active absorption of chloride was significantly increased in milk fed 9 weeke old calves and this effect was further stimulated by early weaning. In conclusion, the data show an increasing active Na+ absorption with age in calf rumen that could not be influenced by early weaning. Similarly, active Cl- absorption was initially increased during postnatal development and this effect could be stimulated further by early weaning.

  18. Groundwater contributions to metal transport in a small river affected by mining and smelting waste.

    PubMed

    Coynel, Alexandra; Schäfer, Jörg; Dabrin, Aymeric; Girardot, Naïg; Blanc, Gérard

    2007-08-01

    The Riou Mort watershed, strongly affected by former coal mining and Zn ore treatment, has been the major source of the historical polymetallic pollution of the Lot-Garonne-Gironde fluvial-estuarine system. Two decades after the end of ore treatment, the former industrial area still contributes important amounts of metals/metalloids from various, partly unidentified, sources to the downstream river system. This study presents the high spatial variability of metal/metalloid (Cd, Zn, As, Sb, U, V) concentrations in water and suspended particulate matter (SPM) from eight observation sites during a short, intense flood event. Despite important dilution effects, the observed concentration levels at the different sites suggested additional Cd and Zn inputs, probably from polluted groundwater. This formerly unknown metal source was then localized and characterized by sampling water and SPM along two longitudinal profiles during different hydrological situations. Groundwater inputs of "truly dissolved" (<0.02 microm) Cd and Zn occurred along approximately 200 m, contributing 43% and 28% to the total annual (2004) Cd and Zn fluxes in the Riou Mort River. The estimated groundwater concentrations of Cd and Zn (2500-6700 and 83,000-170,000 microg l(-1), respectively) in the source zone were consistent with values measured in samples from the near aquifer (5400-13,000 and 200,000-400,000 microg l(-1)). The present work induced concrete remediation actions (pumping and treatment of the polluted groundwater), that are expected to strongly reduce dissolved Cd and Zn emissions into the Riou Mort River.

  19. How dykes affect groundwater transport in the northern part of the Oslo Graben

    NASA Astrophysics Data System (ADS)

    Nilsen, K. H.; Sydnes, M.; Gudmundsson, A.; Larsen, B. T.

    2003-04-01

    In many regions, thick and massif dykes, particularly those of dense basalt of low matrix permeability, are known to be barriers to transverse flow of groundwater. Other thick dykes, however, form in many magma injections, each of which may develop horizontal columnar joints on solidification. These dykes may be relatively permeable because of the columnar joints, and the same applies to many thin dykes. In some dykes, however, the columnar joints are partly, or entirely, filled with secondary minerals, in which case even thin dykes may be barriers to transverse groundwater flow. Because the dyke rock (e.g., basalt) has commonly very different mechanical properties from that of the host rock (granite, gneiss, sedimentary and pyroclastic rocks), stresses tend to concentrate at the contacts between dykes and host rocks and generate groundwater conduits. Thus, even those dykes that are barriers to transverse groundwater flow may be good conduits of dyke-parallel flow. In many areas, for example in Iceland and Tenerife (Canary Islands), dykes collect groundwater and may transport it over long distances. To explore the effects of dykes on groundwater flow in Norway, we made a study of nearly 300 dykes near Gran, in the northern and western part of the Oslo Graben in Southeast Norway. This is a NNE-trending 220 km long and 40-60 km wide graben which was active for approximately 60 Ma, from 305 Ma to 245 Ma. The graben is located in Precambrian basement rocks, mostly consisting of granites, gneisses and metasediments. In the area of Gran, however, the host rock consists primarily of shales, limestones and sandstones. Normal water yields in wells drilled in such rock types in Norway are between 300-5000 l/h, and the normal drill depth lies between 50-150 m. At Gran the depths of the wells range between 20-180 meters and the water yield ranges between 200-10000 l/h. The water in the area has a pH-value of approximately 7.3, which is good drinking water, the norm being 6

  20. Radionuclide bone imaging

    SciTech Connect

    Bassett, L.W.; Gold, R.H.; Webber, M.M.

    1981-12-01

    Radionuclide bone imaging of the skeleton, now well established as the most important diagnostic procedure in detecting bone metastases, is also a reliable method for the evaluation of the progression or regression of metastatic bone disease. The article concentrates on the technetium-99m agents and the value of these agents in the widespread application of low-dose radioisotope scanning in such bone diseases as metastasis, osteomyelitis, trauma, osteonecrosis, and other abnormal skeletal conditions.

  1. Radionuclide therapy beyond radioiodine.

    PubMed

    Gabriel, Michael

    2012-10-01

    For decades, Iodine-131 has been used for the treatment of patients with thyroid cancer. In recent years, increasingly, other radiopharmaceuticals are in clinical use in the treatment of various malignant diseases. Although in principle these therapies-as in all applications of radionuclides-special radiation protection measures are required, a separate nuclear medicine therapy department is not necessary in many cases due to the lower or lack of gamma radiation. In the following article, four different radionuclide therapies are more closely presented which are emerging in the last years. One of them is the "Peptide Receptor Radionuclide Therapy," the so-called PRRT in which radiolabeled somatostatin (SST)-receptor(R) ligands are used in patients with neuroendocrine tumors. On the basis of radiolabeled antibodies against CD20-positive cells, the so-called radioimmunotherapy is used in the treatment of certain forms of malignant lymphoma. In primary or secondary liver tumors, the (90)Y-labeled particles can be administered. Last but not the least, the palliative approach of bone-seeking radiopharmaceuticals is noted in patients with painful bone metastases.

  2. (Radiological assessments of radionuclide releases)

    SciTech Connect

    Hoffman, F.O.

    1990-12-28

    As a consequence of the Chernobyl accident, data have been obtained throughout the Northern Hemisphere on the concentrations of radionuclides in air, vegetation, soil, water, and foodstuffs that could be important means of human exposure. At the IAEA's invitation, the traveler reviewed recently published data and handbook summaries. The traveler evaluated the need for revising the default values recommended in Chapter 5, Terrestrial and Aquatic Food Chain Transport,'' of IAEA Safety Series No. 57. All attempts at revision were made to keep the mathematical complexity of the models to a minimum without substantial underestimation of dose to critical population subgroups. The traveler also served as chairman of the Multiple Pathways Working Group of the Coordinated Research Program on VAMP. This group has been established to test predictions of models assessing multiple exposure pathways potentially leading to human exposure to {sup 137}Cs. Testing is carried out for major components of assessment models that predict deposition, environmental transport, food chain bioaccumulation, and subsequent uptake and retention in the human body and dose due to exposure to external gamma radiation.

  3. Zebrafish ift57, ift88, and ift172 intraflagellar transport mutants disrupt cilia but do not affect hedgehog signaling.

    PubMed

    Lunt, Shannon C; Haynes, Tony; Perkins, Brian D

    2009-07-01

    Cilia formation requires intraflagellar transport (IFT) proteins. Recent studies indicate that mammalian Hedgehog (Hh) signaling requires cilia. It is unclear, however, if the requirement for cilia and IFT proteins in Hh signaling represents a general rule for all vertebrates. Here we examine zebrafish ift57, ift88, and ift172 mutants and morphants for defects in Hh signaling. Although ift57 and ift88 mutants and morphants contained residual maternal protein, the cilia were disrupted. In contrast to previous genetic studies in mouse, mutations in zebrafish IFT genes did not affect the expression of Hh target genes in the neural tube and forebrain and had no quantitative effect on Hh target gene expression. Zebrafish IFT mutants also exhibited no dramatic changes in the craniofacial skeleton, somite formation, or motor neuron patterning. Thus, our data indicate the requirement for cilia in the Hh signal transduction pathway may not represent a universal mechanism in vertebrates.

  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. The cyclophilin A DIAGEOTROPICA gene affects auxin transport in both root and shoot to control lateral root formation.

    PubMed

    Ivanchenko, Maria G; Zhu, Jinsheng; Wang, Bangjun; Medvecká, Eva; Du, Yunlong; Azzarello, Elisa; Mancuso, Stefano; Megraw, Molly; Filichkin, Sergei; Dubrovsky, Joseph G; Friml, Jiří; Geisler, Markus

    2015-02-15

    Cyclophilin A is a conserved peptidyl-prolyl cis-trans isomerase (PPIase) best known as the cellular receptor of the immunosuppressant cyclosporine A. Despite significant effort, evidence of developmental functions of cyclophilin A in non-plant systems has remained obscure. Mutations in a tomato (Solanum lycopersicum) cyclophilin A ortholog, DIAGEOTROPICA (DGT), have been shown to abolish the organogenesis of lateral roots; however, a mechanistic explanation of the phenotype is lacking. Here, we show that the dgt mutant lacks auxin maxima relevant to priming and specification of lateral root founder cells. DGT is expressed in shoot and root, and localizes to both the nucleus and cytoplasm during lateral root organogenesis. Mutation of ENTIRE/IAA9, a member of the auxin-responsive Aux/IAA protein family of transcriptional repressors, partially restores the inability of dgt to initiate lateral root primordia but not the primordia outgrowth. By comparison, grafting of a wild-type scion restores the process of lateral root formation, consistent with participation of a mobile signal. Antibodies do not detect movement of the DGT protein into the dgt rootstock; however, experiments with radiolabeled auxin and an auxin-specific microelectrode demonstrate abnormal auxin fluxes. Functional studies of DGT in heterologous yeast and tobacco-leaf auxin-transport systems demonstrate that DGT negatively regulates PIN-FORMED (PIN) auxin efflux transporters by affecting their plasma membrane localization. Studies in tomato support complex effects of the dgt mutation on PIN expression level, expression domain and plasma membrane localization. Our data demonstrate that DGT regulates auxin transport in lateral root formation.

  6. 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.

  7. 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.

  8. 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.

  9. 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. PMID:23752067

  10. Mountain-Scale Transport of Radioactive Solutes and Colloids Through the Unsaturated Zone of Yucca Mountain, Nevada

    NASA Astrophysics Data System (ADS)

    Moridis, G. J.; Seol, Y.

    2003-12-01

    The US Department of Energy is actively investigating the technical feasibility of permanent disposal of high-level nuclear waste in an appropriate repository to be situated in the unsaturated zone (UZ) at Yucca Mountain (YM), Nevada. The objectives of this study are to evaluate the transport of radioactive solutes and colloids under ambient conditions from the potential repository horizon to the water table and to determine processes and geohydrologic features that significantly affect radionuclide transport. The radionuclide transport model considers the site hydrology, and the effects of the spatial distribution of hydraulic and transport properties in the fractured rocks of the YM subsurface. Several radionuclides (solutes and colloids) with varying properties are investigated. The results of the study indicate that the most important factors affecting radionuclide transport are the 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. Radioactive decay, diffusion from the fractures into the matrix, and subsequent sorption (for solutes) or filtration (for colloids) onto, are the main retardation processes. For solutes, arrival times at the watertable increase with the sorption distribution coefficients of the various species, and may have to account for contributions from the decay daughters of certain radionuclides. Changes in future climatic conditions can have a significant effect on transport, as increasing infiltration leads to faster transport to the water table. The transport of colloids is strongly influenced by their size (as it affects diffusion into the matrix, straining at hydrogeologic unit interfaces and transport velocity) and by the fracture attributes.

  11. Transportation.

    ERIC Educational Resources Information Center

    Crank, Ron

    This instructional unit is one of 10 developed by students on various energy-related areas that deals specifically with transportation and energy use. Its objective is for the student to be able to discuss the implication of energy usage as it applies to the area of transportation. Some topics covered are efficiencies of various transportation…

  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. 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

  14. Reduced Expression of the Vesicular Acetylcholine Transporter and Neurotransmitter Content Affects Synaptic Vesicle Distribution and Shape in Mouse Neuromuscular Junction

    PubMed Central

    Rodrigues, Hermann A.; Fonseca, Matheus de C.; Camargo, Wallace L.; Lima, Patrícia M. A.; Martinelli, Patrícia M.; Naves, Lígia A.; Prado, Vânia F.; Prado, Marco A. M.; Guatimosim, Cristina

    2013-01-01

    In vertebrates, nerve muscle communication is mediated by the release of the neurotransmitter acetylcholine packed inside synaptic vesicles by a specific vesicular acetylcholine transporter (VAChT). Here we used a mouse model (VAChT KDHOM) with 70% reduction in the expression of VAChT to investigate the morphological and functional consequences of a decreased acetylcholine uptake and release in neuromuscular synapses. Upon hypertonic stimulation, VAChT KDHOM mice presented a reduction in the amplitude and frequency of miniature endplate potentials, FM 1–43 staining intensity, total number of synaptic vesicles and altered distribution of vesicles within the synaptic terminal. In contrast, under electrical stimulation or no stimulation, VAChT KDHOM neuromuscular junctions did not differ from WT on total number of vesicles but showed altered distribution. Additionally, motor nerve terminals in VAChT KDHOM exhibited small and flattened synaptic vesicles similar to that observed in WT mice treated with vesamicol that blocks acetylcholine uptake. Based on these results, we propose that decreased VAChT levels affect synaptic vesicle biogenesis and distribution whereas a lower ACh content affects vesicles shape. PMID:24260111

  15. Reduced expression of the vesicular acetylcholine transporter and neurotransmitter content affects synaptic vesicle distribution and shape in mouse neuromuscular junction.

    PubMed

    Rodrigues, Hermann A; Fonseca, Matheus de C; Camargo, Wallace L; Lima, Patrícia M A; Martinelli, Patrícia M; Naves, Lígia A; Prado, Vânia F; Prado, Marco A M; Guatimosim, Cristina

    2013-01-01

    In vertebrates, nerve muscle communication is mediated by the release of the neurotransmitter acetylcholine packed inside synaptic vesicles by a specific vesicular acetylcholine transporter (VAChT). Here we used a mouse model (VAChT KD(HOM)) with 70% reduction in the expression of VAChT to investigate the morphological and functional consequences of a decreased acetylcholine uptake and release in neuromuscular synapses. Upon hypertonic stimulation, VAChT KD(HOM) mice presented a reduction in the amplitude and frequency of miniature endplate potentials, FM 1-43 staining intensity, total number of synaptic vesicles and altered distribution of vesicles within the synaptic terminal. In contrast, under electrical stimulation or no stimulation, VAChT KD(HOM) neuromuscular junctions did not differ from WT on total number of vesicles but showed altered distribution. Additionally, motor nerve terminals in VAChT KD(HOM) exhibited small and flattened synaptic vesicles similar to that observed in WT mice treated with vesamicol that blocks acetylcholine uptake. Based on these results, we propose that decreased VAChT levels affect synaptic vesicle biogenesis and distribution whereas a lower ACh content affects vesicles shape. PMID:24260111

  16. Serotonin transporter 5HTTLPR polymorphism and affective disorders: no evidence of association in a large European multicenter study.

    PubMed

    Mendlewicz, Julien; Massat, Isabelle; Souery, Daniel; Del-Favero, Jurgen; Oruc, Lilijana; Nöthen, Markus M; Blackwood, Douglas; Muir, Walter; Battersby, Sharon; Lerer, Beny; Segman, Ronen H; Kaneva, Radka; Serretti, Alessandro; Lilli, Roberta; Lorenzi, Christian; Jakovljevic, Miro; Ivezic, Sladana; Rietschel, Marcella; Milanova, Vihra; Van Broeckhoven, Christine

    2004-05-01

    The available data from preclinical and pharmacological studies on the role of the serotonin transporter (5-HTT) support the hypothesis that a dysfunction in brain serotonergic system activity contributes to the vulnerability to affective disorders (AD). 5-HTT is the major site of serotonin reuptake into the presynaptic neuron, and it has been shown that the polymorphic repeat polymorphism in the 5-HTT promotor region (5-HTTLPR) may affect gene-transcription activity. 5-HTT maps to chromosome 17 at position 17q11.17-q12, and the 5-HTTLPR polymorphisms have been extensively investigated in AD with conflicting results. The present study tested the genetic contribution of the 5-HTTLPR polymorphism in a large European multicenter case-control sample, including 539 unipolar (UPAD), 572 bipolar patients (BPAD), and 821 controls (C). Our European collaboration has led to efforts to optimize a methodology that attenuates some of the major limitations of the case-control association approach. No association was found with primary psychiatric diagnosis (UPAD and BPAD) and with phenotypic traits (family history of AD, suicidal attempt, and presence of psychotic features). Our negative findings are not attributable to the lack of statistical power, and may contribute to clarify the role of 5-HTTLPR polymorphism in AD.

  17. Resuspension and redistribution of radionuclides during grassland and forest fires in the Chernobyl exclusion zone: part I. Fire experiments.

    PubMed

    Yoschenko, V I; Kashparov, V A; Protsak, V P; Lundin, S M; Levchuk, S E; Kadygrib, A M; Zvarich, S I; Khomutinin, Yu V; Maloshtan, I M; Lanshin, V P; Kovtun, M V; Tschiersch, J

    2006-01-01

    Controlled burning of experimental plots of forest or grassland in the Chernobyl exclusion zone has been carried out in order to estimate the parameters of radionuclide resuspension, transport and deposition during forest and grassland fires and to evaluate the working conditions of firemen. An increase of several orders of magnitude of the airborne radionuclide concentration was observed in the territory near the fire area. The resuspension factor for (137)Cs and (90)Sr was determined to range from 10(-6) to 10(-5) m(-1), and for the plutonium radionuclides from 10(-7) to 10(-6) m(-1) (related to the nuclides in the combustible biomass). These values are 2 orders of magnitude lower if they are calculated relatively to the total contamination density (including the nuclides in the soil). The radionuclide fallout along the plume axis is negligible in comparison to the existing contamination. However, the additional inhalation dose for firemen exposed in the affected area can reach the level of the additional external irradiation in the period of their mission. The plutonium nuclides constitute the dominating contribution to the inhalation dose. PMID:16213067

  18. History of medical radionuclide production.

    PubMed

    Ice, R D

    1995-11-01

    Radionuclide production for medical use originally was incidental to isotope discoveries by physicists and chemists. Once the available radionuclides were identified they were evaluated for potential medical use. Hevesy first used 32P in 1935 to study phosphorous metabolism in rats. Since that time, the development of cyclotrons, linear accelerators, and nuclear reactors have produced hundreds of radionuclides for potential medical use. The history of medical radionuclide production represents an evolutionary, interdisciplinary development of applied nuclear technology. Today the technology is represented by a mature industry and provides medical benefits to millions of patients annually.

  19. Osteopetrosis: radiological & radionuclide imaging.

    PubMed

    Sit, Cherry; Agrawal, Kanhaiyalal; Fogelman, Ignac; Gnanasegaran, Gopinath

    2015-01-01

    Osteopetrosis is a rare inherited bone disease where bones harden and become abnormally dense. While the diagnosis is clinical, it also greatly relies on appearance of the skeleton radiographically. X-ray, radionuclide bone scintigraphy and magnetic resonance imaging have been reported to identify characteristics of osteopetrosis. We present an interesting case of a 59-year-old man with a history of bilateral hip fractures. He underwent (99m)Tc-methylene diphosphonate whole body scan supplemented with single-photon emission computed tomography/computed tomography of spine, which showed increased uptake in the humeri, tibiae and femora, which were in keeping with osteopetrosis.

  20. 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

  1. Targeted radionuclide therapy

    SciTech Connect

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

    2008-07-15

    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.

  2. 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

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. Natural variation in the expression of ORGANIC CATION TRANSPORTER 1 affects root length responses to cadaverine in Arabidopsis.

    PubMed

    Strohm, Allison K; Vaughn, Laura M; Masson, Patrick H

    2015-02-01

    Polyamines, including cadaverine, are organic cations that affect numerous biological processes including transcription, translation, cell signalling, and ion channel activity. They often function in biotic and abiotic stress responses in plants. Because little is known about how plants respond to cadaverine, a quantitative natural variation approach was used to identify genetic factors that contribute to this response. Here it is shown that Arabidopsis thaliana accessions have varying root length responses to exogenous cadaverine: Cape Verde Islands (Cvi) was one of the most resistant accessions tested, whereas Landsberg erecta (Ler) was one of the most sensitive. Recombinant inbred lines, near isogenic lines, and a microarray were used to show that variation in ORGANIC CATION TRANSPORTER 1 (OCT1) is at least partially responsible for this difference. OCT1 expression was higher in Cvi than in Ler, and oct1 mutants were more sensitive to cadaverine than wild-type plants. In oct1 mutants transformed with an ectopic copy of OCT1 originating from either Cvi or Ler, the expression level of the transgene, not its accession, correlated with the cadaverine response. These results suggest that decreased OCT1 expression confers cadaverine sensitivity in some accessions. PMID:25403917

  8. 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

  9. 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.

  10. 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.

  11. Code System for Radionuclide Migration Calculations.

    1988-02-26

    Version: 00 IONMIG is used to calculate the far-field transport of decaying radionuclides through a porous medium by diffusion and convection. It was specifically developed in support of the U. S. Subseabed Disposal program. For user specified velocity and temperature fields the convection-diffusion equation is solved in a sorbing porous medium. The sorption may be a function of species type, concentration, vertical position and local temperature. The formulation used is applicable to two-dimensional planar ormore » axisymmetric geometries. Zero flux conditions are assumed at all but the upper boundaries.« less

  12. Assessing field-scale migration of radionuclides at the Nevada Test Site: "mobile" species.

    PubMed

    Hu, Q H; Rose, T P; Zavarin, M; Smith, D K; Moran, J E; Zhao, P H

    2008-10-01

    Many long-lived radionuclides are present in groundwater at the Nevada Test Site (NTS) as a result of 828 underground nuclear weapons tests conducted between 1951 and 1992. In conjunction with a comprehensive geochemical review of radionuclides (3H, 14C, 36Cl, 99Tc and 129I) that are presumably mobile in the subsurface, we synthesized a body of radionuclide activity data measured from groundwater samples collected at 18 monitoring wells, to qualitatively assess their migration at the NTS over distances of hundreds of meters and over timescales of decades. Tritium and 36Cl showed little evidence of retardation, while the transport of 14C may have been retarded by its isotopic exchange with carbonate minerals in the aquifer. Observed local reducing conditions (either natural or test-induced) will impact the mobility of certain redox-sensitive radionuclides (especially 99Tc) that were otherwise soluble and readily transported under oxidizing conditions. Conversely, strongly oxidizing conditions may impact the mobility of 129I which is mobile under reducing conditions. The effect of iodine speciation on its transport deserves further attention. Indication of delayed transport of some "mobile" radionuclides (especially 99Tc) in the groundwater at the NTS suggested the importance of redox conditions of the natural system in controlling the fate and transport of radionuclides, which has implications in the enhanced performance of the potential Yucca Mountain repository, located adjacent to the NTS, to store high-level nuclear wastes as well as management of radionuclide contamination in legacy nuclear operations facilities.

  13. Cytokinin treatments affect the apical-basal patterning of the Arabidopsis gynoecium and resemble the effects of polar auxin transport inhibition

    PubMed Central

    Zúñiga-Mayo, Victor M.; Reyes-Olalde, J. Irepan; Marsch-Martinez, Nayelli; de Folter, Stefan

    2014-01-01

    The apical-basal axis of the Arabidopsis gynoecium is established early during development and is divided into four elements from the bottom to the top: the gynophore, the ovary, the style, and the stigma. Currently, it is proposed that the hormone auxin plays a critical role in the correct apical-basal patterning through a concentration gradient from the apical to the basal part of the gynoecium, as chemical inhibition of polar auxin transport through 1-N-naphtylphtalamic acid (NPA) application, severely affects the apical-basal patterning of the gynoecium. In this work, we show that the apical-basal patterning of gynoecia is also sensitive to exogenous cytokinin (benzyl amino purine, BAP) application in a similar way as to NPA. BAP and NPA treatments were performed in different mutant backgrounds where either cytokinin perception or auxin transport and perception were affected. We observed that cytokinin and auxin signaling mutants are hypersensitive to NPA treatment, and auxin transport and signaling mutants are hypersensitive to BAP treatment. BAP effects in apical-basal gynoecium patterning are very similar to the effects of NPA, therefore, it is possible that BAP affects auxin transport in the gynoecium. Indeed, not only the cytokinin-response TCS::GFP marker, but also the auxin efflux carrier PIN1 (PIN1::PIN1:GFP) were both affected in BAP-induced valveless gynoecia, suggesting that the BAP treatment producing the morphological changes has an impact on both in the response pattern to cytokinin and on auxin transport. In summary, we show that cytokinin affects proper apical-basal gynoecium patterning in Arabidopsis in a similar way to the inhibition of polar auxin transport, and that auxin and cytokinin mutants and markers suggest a relation between both hormones in this process. PMID:24860582

  14. Cytokinin treatments affect the apical-basal patterning of the Arabidopsis gynoecium and resemble the effects of polar auxin transport inhibition.

    PubMed

    Zúñiga-Mayo, Victor M; Reyes-Olalde, J Irepan; Marsch-Martinez, Nayelli; de Folter, Stefan

    2014-01-01

    The apical-basal axis of the Arabidopsis gynoecium is established early during development and is divided into four elements from the bottom to the top: the gynophore, the ovary, the style, and the stigma. Currently, it is proposed that the hormone auxin plays a critical role in the correct apical-basal patterning through a concentration gradient from the apical to the basal part of the gynoecium, as chemical inhibition of polar auxin transport through 1-N-naphtylphtalamic acid (NPA) application, severely affects the apical-basal patterning of the gynoecium. In this work, we show that the apical-basal patterning of gynoecia is also sensitive to exogenous cytokinin (benzyl amino purine, BAP) application in a similar way as to NPA. BAP and NPA treatments were performed in different mutant backgrounds where either cytokinin perception or auxin transport and perception were affected. We observed that cytokinin and auxin signaling mutants are hypersensitive to NPA treatment, and auxin transport and signaling mutants are hypersensitive to BAP treatment. BAP effects in apical-basal gynoecium patterning are very similar to the effects of NPA, therefore, it is possible that BAP affects auxin transport in the gynoecium. Indeed, not only the cytokinin-response TCS::GFP marker, but also the auxin efflux carrier PIN1 (PIN1::PIN1:GFP) were both affected in BAP-induced valveless gynoecia, suggesting that the BAP treatment producing the morphological changes has an impact on both in the response pattern to cytokinin and on auxin transport. In summary, we show that cytokinin affects proper apical-basal gynoecium patterning in Arabidopsis in a similar way to the inhibition of polar auxin transport, and that auxin and cytokinin mutants and markers suggest a relation between both hormones in this process. PMID:24860582

  15. APT radionuclide production experiment

    SciTech Connect

    Ullmann, J.L.; Gavron, A.; King, J.D.

    1994-07-02

    Tritium ({sup 3}H, a heavy isotope of hydrogen) is produced by low energy neutron-induced reactions on various elements. One such reaction is n+{sup 3}He {yields}>{sup 3}H+{sup 1}H in which {sup 3}He is transmuted to tritium. Another reaction, which has been used in reactor production of tritium, is the n+{sup 6}Li {yields}> {sup 3}H+{sup 4}He reaction. Accelerator Production of Tritium relies on a high-energy proton beam to produce these neutrons using the spallation reaction, in which high-energy proton beam to produce these neutrons using the spallation reaction, in which high-energy protons reacting with a heavy nucleus produce a shower of low-energy neutrons and a lower-mass residual nucleus. It is important to quantify the residual radionuclides produced in the spallation target for two reasons. From an engineering point of view, one must understand short-lived isotopes that may contribute to decay heat. From a safety viewpoint, one must understand what nuclei and decay gammas are produced in order to design adequate shielding, to estimate ultimate waste disposal problems, and to predict possible effects due to accidental dispersion during operation. The authors have performed an experiment to measure the production of radioisotopes in stopping-length W and Pb targets irradiated by a 800 MeV proton beam, and are comparing the results to values obtained from calculations using LAHET and MCNP. The experiment was designed to pay particular attention to the short half-life radionuclides, which have not been previously measured. In the following, they present details of the experiment, explain how they analyzed the data and obtain the results, how they perform the calculations, and finally, how the experimental data agree with the calculations.

  16. Aging differentially affects human skeletal muscle amino acid transporter expression when essential amino acids are ingested after exercise

    PubMed Central

    Dickinson, Jared M.; Drummond, Micah J.; Coben, Jennifer R.; Volpi, Elena; Rasmussen, Blake B.

    2012-01-01

    Background & Aims Amino acid transporters have been proposed as regulators of protein synthesis. The primary aim of this study was to determine whether amino acid transporter expression is increased in human muscle following resistance exercise (RE) coupled with essential amino acid (EAA) ingestion, and whether a differential response occurs with aging. Secondly, we aimed to compare this response to a previous study examining RE alone. Methods Young (n=7, 30±2yr) and older men (n=6, 70±2yr) ingested EAA 1h after RE. Muscle biopsies were obtained at rest and 3 and 6h postexercise to examine amino acid transporter mRNA and protein expression. Results In both age groups, RE+EAA increased mRNA of L-type amino acid transporter 1 (LAT1)/solute linked carrier (SLC)7A5, sodium-coupled neutral amino acid transporter 2 (SNAT2)/SLC38A2, and cationic amino acid transporter 1/SLC7A1 (p<0.05). SNAT2 protein increased in young at 3 and 6h (p<0.05), whereas old maintained higher LAT1 protein (p<0.05). Compared to RE alone, RE+EAA enhanced amino acid transporter expression only in young (p<0.05). Conclusions RE increases muscle amino acid transporter expression in young and older adults, however, postexercise EAA ingestion enhances amino acid transporter expression only in young indicating that aging may influence the function of specific amino acid transporters. PMID:22889597

  17. 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.

  18. 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.

  19. SATURATED ZONE FLOW AND TRANSPORT MODEL ABSTRACTION

    SciTech Connect

    B.W. ARNOLD

    2004-10-27

    The purpose of the saturated zone (SZ) flow and transport model abstraction task is to provide radionuclide-transport simulation results for use in the total system performance assessment (TSPA) for license application (LA) calculations. This task includes assessment of uncertainty in parameters that pertain to both groundwater flow and radionuclide transport in the models used for this purpose. This model report documents the following: (1) The SZ transport abstraction model, which consists of a set of radionuclide breakthrough curves at the accessible environment for use in the TSPA-LA simulations of radionuclide releases into the biosphere. These radionuclide breakthrough curves contain information on radionuclide-transport times through the SZ. (2) The SZ one-dimensional (I-D) transport model, which is incorporated in the TSPA-LA model to simulate the transport, decay, and ingrowth of radionuclide decay chains in the SZ. (3) The analysis of uncertainty in groundwater-flow and radionuclide-transport input parameters for the SZ transport abstraction model and the SZ 1-D transport model. (4) The analysis of the background concentration of alpha-emitting species in the groundwater of the SZ.

  20. Computerized Radiological Risk Investigation System for Assessing Doses and Health Risks from Atmospheric Releases of Radionuclides.

    1998-11-10

    Version: 00 CRRIS consists 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 be used alone for various assessment applications. Because of its modular structure, CRRIS allows assessments to be tailored to the user's needs. Radionuclides are handled by CRRIS either in terms of the released radionuclides or the exposure radionuclides which consist of both themore » released nuclides and decay products that build up during environmental transport. Atmospheric dispersion calculations are performed by the ANEMOS computer code for distances less than 100 km and by the RETADD-II computer code for regional-scale distances. Both codes estimate annual-average air concentrations and ground deposition rates by location. SUMIT will translate and scale multiple ANEMOS runs onto a master grid. TERRA reads radionuclide air concentrations and deposition rates to estimate concentrations of radionuclides in food and surface soil. Radiologic decay and ingrowth, soil leaching, and transport through the food chain are included in the calculations. MLSOIL computes an effective radionuclide ground-surface concentration to be used in computing external health effects. The five-layer model of radionuclide transport through soil in MLSOIL provides an alternative to the single-layer model used in TERRA. DFSOIL computes dose factors used in MLSOIL to compute doses from the five soil layers and from the ground surface. ANDROS reads environmental concentrations of radionuclides computed by the other CRRIS codes and produces tables of doses and risks to individuals or populations from atmospheric releases of radionuclides.« less

  1. Computerized Radiological Risk Investigation System for Assessing Doses and Health Risks from Atmospheric Releases of Radionuclides.

    SciTech Connect

    RAINE, III, DUDLEY A.

    1998-11-10

    Version: 00 CRRIS consists 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 be used alone for various assessment applications. Because of its modular structure, CRRIS allows assessments to be tailored to the user's needs. Radionuclides are handled by CRRIS either in terms of the released radionuclides or the exposure radionuclides which consist of both the released nuclides and decay products that build up during environmental transport. Atmospheric dispersion calculations are performed by the ANEMOS computer code for distances less than 100 km and by the RETADD-II computer code for regional-scale distances. Both codes estimate annual-average air concentrations and ground deposition rates by location. SUMIT will translate and scale multiple ANEMOS runs onto a master grid. TERRA reads radionuclide air concentrations and deposition rates to estimate concentrations of radionuclides in food and surface soil. Radiologic decay and ingrowth, soil leaching, and transport through the food chain are included in the calculations. MLSOIL computes an effective radionuclide ground-surface concentration to be used in computing external health effects. The five-layer model of radionuclide transport through soil in MLSOIL provides an alternative to the single-layer model used in TERRA. DFSOIL computes dose factors used in MLSOIL to compute doses from the five soil layers and from the ground surface. ANDROS reads environmental concentrations of radionuclides computed by the other CRRIS codes and produces tables of doses and risks to individuals or populations from atmospheric releases of radionuclides.

  2. 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. PMID:9718743

  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. Modeling coupled water flow, solute transport and geochemical reactions affecting heavy metal migration in a podzol soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many or most subsurface pollution problems at the field scale involve such simultaneous processes as water flow, multicomponent solute transport, heat transport and biogeochemical processes and reactions. Process-based models that integrate these various processes can be valuable tools for investiga...

  5. 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.

  6. Radionuclide salivary gland imaging

    SciTech Connect

    Mishkin, F.S.

    1981-10-01

    Salivary gland imaging with 99mTc as pertechnetate provides functional information concerning trapping and excretion of the parotid and submandibular glands. Anatomic information gained often adds little to clinical evaluation. On the other hand, functional information may detect subclinical involvement, which correlates well with biopsy of the minor labial salivary glands. Salivary gland abnormalities in systemic disease such as sarcoidosis, rheumatoid arthritis, lupus erythematosus, and other collagenvascular disorders may be detected before they result in the clinical manifestaions of Sjoegren's syndrome. Such glands, after initially demonstrating increased trapping in the acute phase, tend to have decreased trapping and failure to discharge pertechnetate in response to an appropriate physiologic stimulus. Increased uptake of gallium-67 citrate often accompanies these findings. Inflammatory parotitis can be suspected when increased perfusion is evident on radionuclide angiography with any agent. The ability of the salivary gland image to detect and categorize mass lesions, which result in focal areas of diminished activity such as tumors, cysts, and most other masses, is disappointing, while its ability to detect and categorize Warthin's tumor, which concentrates pertechnetate, is much more valuable, although not specific.

  7. 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.

  8. 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.

  9. Regulation of sulfate uptake and expression of sulfate transporter genes in Brassica oleracea as affected by atmospheric H(2)S and pedospheric sulfate nutrition.

    PubMed

    Buchner, Peter; Stuiver, C Elisabeth E; Westerman, Sue; Wirtz, Markus; Hell, Rüdiger; Hawkesford, Malcolm J; De Kok, Luit J

    2004-10-01

    Demand-driven signaling will contribute to regulation of sulfur acquisition and distribution within the plant. To investigate the regulatory mechanisms pedospheric sulfate and atmospheric H(2)S supply were manipulated in Brassica oleracea. Sulfate deprivation of B. oleracea seedlings induced a rapid increase of the sulfate uptake capacity by the roots, accompanied by an increased expression of genes encoding specific sulfate transporters in roots and other plant parts. More prolonged sulfate deprivation resulted in an altered shoot-root partitioning of biomass in favor of the root. B. oleracea was able to utilize atmospheric H(2)S as S-source; however, root proliferation and increased sulfate transporter expression occurred as in S-deficient plants. It was evident that in B. oleracea there was a poor shoot to root signaling for the regulation of sulfate uptake and expression of the sulfate transporters. cDNAs corresponding to 12 different sulfate transporter genes representing the complete gene family were isolated from Brassica napus and B. oleracea species. The sequence analysis classified the Brassica sulfate transporter genes into four different groups. The expression of the different sulfate transporters showed a complex pattern of tissue specificity and regulation by sulfur nutritional status. The sulfate transporter genes of Groups 1, 2, and 4 were induced or up-regulated under sulfate deprivation, although the expression of Group 3 sulfate transporters was not affected by the sulfate status. The significance of sulfate, thiols, and O-acetylserine as possible signal compounds in the regulation of the sulfate uptake and expression of the transporter genes is evaluated. PMID:15377780

  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. 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

  12. 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.

  13. 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.

  14. 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.

  15. Identification of residues in ABCG2 affecting protein trafficking and drug transport, using co-evolutionary analysis of ABCG sequences

    PubMed Central

    Haider, Ameena J.; Cox, Megan H.; Jones, Natalie; Goode, Alice J.; Bridge, Katherine S.; Wong, Kelvin; Briggs, Deborah; Kerr, Ian D.

    2015-01-01

    ABCG2 is an ABC (ATP-binding cassette) transporter with a physiological role in urate transport in the kidney and is also implicated in multi-drug efflux from a number of organs in the body. The trafficking of the protein and the mechanism by which it recognizes and transports diverse drugs are important areas of research. In the current study, we have made a series of single amino acid mutations in ABCG2 on the basis of sequence analysis. Mutant isoforms were characterized for cell surface expression and function. One mutant (I573A) showed disrupted glycosylation and reduced trafficking kinetics. In contrast with many ABC transporter folding mutations which appear to be ‘rescued’ by chemical chaperones or low temperature incubation, the I573A mutation was not enriched at the cell surface by either treatment, with the majority of the protein being retained in the endoplasmic reticulum (ER). Two other mutations (P485A and M549A) showed distinct effects on transport of ABCG2 substrates reinforcing the role of TM helix 3 in drug recognition and transport and indicating the presence of intracellular coupling regions in ABCG2. PMID:26294421

  16. Anion transport properties of amine and amide-sidechained peptides are affected by charge and phospholipid composition†

    PubMed Central

    You, Lei; Li, Ruiqiong; Gokel, George W.

    2009-01-01

    Four synthetic anion transporters (SATs) having the general formula (n-C18H37)2N-COCH2OCH2CO-(Gly)3Pro-Lys(ε-N-R)-(Gly)2-O-n-C7H15 were prepared and studied