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Sample records for source zone concentrated

  1. Concentration, composition and sources of PAHs in the coastal sediments of the exclusive economic zone (EEZ) of Qatar, Arabian Gulf.

    Science.gov (United States)

    Soliman, Y S; Al Ansari, E M S; Wade, T L

    2014-08-30

    Surface sediments were collected from sixteen locations in order to assess levels and sources of polycyclic aromatic hydrocarbons (PAHs) in sediments of Qatar exclusive economic zone (EEZ). Samples were analyzed for 16 parent PAHs, 18 alkyl homologs and for dibenzothiophenes. Total PAHs concentration (∑PAHs) ranged from 2.6 ng g(-1) to 1025 ng g(-1). The highest PAHs concentrations were in sediments in and adjacent to harbors. Alkylated PAHs predominated most of the sampling locations reaching up to 80% in offshore locations. Parent PAHs and parent high molecular weight PAHs dominated location adjacent to industrial activities and urban areas. The origin of PAHs sources to the sediments was elucidated using ternary plot, indices, and molecular ratios of specific compounds such as (Ant/Phe+Ant), (Flt/Flt+Pyr). PAHs inputs to most coastal sites consisted of mixture of petroleum and combustion derived sources. However, inputs to the offshore sediments were mainly of petroleum origin. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Polycyclic aromatic hydrocarbons and black carbon in intertidal sediments of China coastal zones: Concentration, ecological risk, source and their relationship

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiaofei [School of Geographical Sciences, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062 (China); Hou, Lijun [State Key Laboratory of Estuarine and Coastal Research, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062 (China); Li, Ye [School of Geographical Sciences, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062 (China); Liu, Min, E-mail: mliu@geo.ecnu.edu.cn [School of Geographical Sciences, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062 (China); Key Laboratory of Geographic Information Science, Ministry of Education, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062 (China); Lin, Xianbiao; Cheng, Lv [School of Geographical Sciences, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062 (China)

    2016-10-01

    Polycyclic aromatic hydrocarbons (PAHs) and black carbon (BC) have attracted many attentions, especially in the coastal environments. In this study, spatiotemporal distributions of PAHs and BC, and the correlations between BC and PAHs were investigated in the intertidal sediments of China coastal zones. BC in sediments was measured through dichromate oxidation (BC{sub Cr}) and thermal oxidation (BC{sub CTO}). The concentrations of BC{sub Cr} in the intertidal sediments ranged between 0.61 and 6.32 mg g{sup −1}, while BC{sub CTO} ranged between 0.57 and 4.76 mg g{sup −1}. Spatial variations of δ{sup 13}C signatures in TOC and BC were observed, varying from − 21.13‰ to − 24.87‰ and from − 23.53‰ to − 16.78‰, respectively. PAH contents of sediments ranged from 195.9 to 4610.2 ng g{sup −1} in winter and 98.2 to 2796.5 ng g{sup −1} in summer, and significantly seasonal variations were observed at most sampling sites. However, the results of potential toxicity assessment indicated low ecological risk in the intertidal sediments of China coastal zones. Greater concentrations of PAHs measured in the sediments of estuarine environments indicated that rivers runoff may have been responsible for the higher PAH pollution levels in the intertidal sediments of China coastal zones. Pearson's correlation analysis suggested that pyrogenic compounds of PAH were significantly related to BC, due to that both BC and these compounds derived mainly from the combustion process of fossil fuels and biomass. Overall, increasing energy consumptions caused by anthropogenic activities can contribute more emissions of BC as well as PAHs and thus improve the importance of BC in indicating pyrogenic compounds of PAHs in the intertidal sediments of China coastal zones. - Highlights: • River runoffs were responsible for the high PAH pollution levels in the study area. • BC and PAHs derived mainly from the combustion process of fossil fuels. • BC was associated

  3. Pollution concentration estimates in ecologically important zones

    Energy Technology Data Exchange (ETDEWEB)

    Skiba, Y.N. [Mexico City Univ. (Mexico). Center for Atmospheric Sciences

    1995-12-31

    Method based on using the pollutant transport equation and the adjoint technique is described here for estimating the pollutant concentration level in ecologically important zones. The method directly relates the pollution level in such zones with the power of the pollution sources and the initial pollution field. Assuming that the wind or current velocities are known (from climatic data or dynamic model), the main and adjoint pollutant transport equations can be considered in a limited area to solve such theoretically and practically important problems as: (1) optimal location of new industries in a given region with the aim to minimize the pollution concentration in certain ecologically important zones, (2) optimization of emissions from operating industries, (3) detection of the plants violating sanitary regulations, (4) analysis of the emissions coming from the vehicle traffic (such emissions can be included in the model by means of the linear pollution sources located along the main roadways), (5) estimation of the oil pollution in various ecologically important oceanic (sea) zones in case of accident with the oil tanker, (6) evaluation of the sea water desalination level in estuary regions, and others. These equations considered in a spherical shell domain can also be applied to the problems of transporting the pollutants from a huge industrial complex, or from the zone of an ecological catastrophe similar to the Chernobyl one

  4. Pollution concentration estimates in ecologically important zones

    Energy Technology Data Exchange (ETDEWEB)

    Skiba, Y N [Mexico City Univ. (Mexico). Center for Atmospheric Sciences

    1996-12-31

    Method based on using the pollutant transport equation and the adjoint technique is described here for estimating the pollutant concentration level in ecologically important zones. The method directly relates the pollution level in such zones with the power of the pollution sources and the initial pollution field. Assuming that the wind or current velocities are known (from climatic data or dynamic model), the main and adjoint pollutant transport equations can be considered in a limited area to solve such theoretically and practically important problems as: (1) optimal location of new industries in a given region with the aim to minimize the pollution concentration in certain ecologically important zones, (2) optimization of emissions from operating industries, (3) detection of the plants violating sanitary regulations, (4) analysis of the emissions coming from the vehicle traffic (such emissions can be included in the model by means of the linear pollution sources located along the main roadways), (5) estimation of the oil pollution in various ecologically important oceanic (sea) zones in case of accident with the oil tanker, (6) evaluation of the sea water desalination level in estuary regions, and others. These equations considered in a spherical shell domain can also be applied to the problems of transporting the pollutants from a huge industrial complex, or from the zone of an ecological catastrophe similar to the Chernobyl one

  5. Reductive dechlorination of trichloroethene DNAPL source zones: source zone architecture versus electron donor availability

    Science.gov (United States)

    Krol, M.; Kokkinaki, A.; Sleep, B.

    2014-12-01

    The persistence of dense-non-aqueous-phase liquids (DNAPLs) in the subsurface has led practitioners and regulatory agencies to turn towards low-maintenance, low-cost remediation methods. Biological degradation has been suggested as a possible solution, based on the well-proven ability of certain microbial species to break down dissolved chlorinated ethenes under favorable conditions. However, the biodegradation of pure phase chlorinated ethenes is subject to additional constraints: the continuous release of electron acceptor at a rate governed by mass transfer kinetics, and the temporal and spatial heterogeneity of DNAPL source zones which leads to spatially and temporally variable availability of the reactants for reductive dechlorination. In this work, we investigate the relationship between various DNAPL source zone characteristics and reaction kinetics using COMPSIM, a multiphase groundwater model that considers non-equilibrium mass transfer and Monod-type kinetics for reductive dechlorination. Numerical simulations are performed for simple, homogeneous trichloroethene DNAPL source zones to demonstrate the effect of single source zone characteristics, as well as for larger, more realistic heterogeneous source zones. It is shown that source zone size, and mass transfer kinetics may have a decisive effect on the predicted bio-enhancement. Finally, we evaluate the performance of DNAPL bioremediation for realistic, thermodynamically constrained, concentrations of electron donor. Our results indicate that the latter may be the most important limitation for the success of DNAPL bioremediation, leading to reduced bio-enhancement and, in many cases, comparable performance with water flooding.

  6. Persulfate injection into a gasoline source zone.

    Science.gov (United States)

    Sra, Kanwartej S; Thomson, Neil R; Barker, Jim F

    2013-07-01

    One pore volume of unactivated sodium persulfate was delivered into an emplaced gasoline residual source zone at CFB Borden. Concentrations of inorganic species (S2O8(2-), SO4(2-), Na(+), dissolved inorganic carbon (DIC)) and selected gasoline compounds (benzene, toluene, ethylbenzene, xylenes, trimethylbenzenes and naphthalene) were monitored across a transect equipped with 90 multilevel sampling points for >10months post-injection. Mass loading (M˙) of compounds constructed from the transect data was used for assessment purposes. Breakthrough of inorganic species was observed when the injection slug crossed the monitoring transect. An increase in [Formula: see text] indicated persulfate consumption during oxidation of gasoline compounds or degradation due to the interaction with aquifer materials. M˙DIC increased by >100% suggesting some mineralization of gasoline compounds during treatment. Mass loading for all the monitored gasoline compounds reduced by 46 to 86% as the inorganic slug crossed the monitoring transect. The cumulative mass discharge across the monitoring transect was 19 to 58% lower than that expected without persulfate injection. After the inorganic injection slug was flushed from the source zone a partial rebound (40 to 80% of baseline levels) of mass discharge of the monitored gasoline compounds was observed. The ensemble of data collected provides insight into the fate and transport of the injected persulfate solution, and the accompanying treatment of a gasoline the source zone. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Persulfate injection into a gasoline source zone

    Science.gov (United States)

    Sra, Kanwartej S.; Thomson, Neil R.; Barker, Jim F.

    2013-07-01

    One pore volume of unactivated sodium persulfate was delivered into an emplaced gasoline residual source zone at CFB Borden. Concentrations of inorganic species (S2O82 -, SO42 -, Na+, dissolved inorganic carbon (DIC)) and selected gasoline compounds (benzene, toluene, ethylbenzene, xylenes, trimethylbenzenes and naphthalene) were monitored across a transect equipped with 90 multilevel sampling points for > 10 months post-injection. Mass loading (M˙) of compounds constructed from the transect data was used for assessment purposes. Breakthrough of inorganic species was observed when the injection slug crossed the monitoring transect. An increase in M indicated persulfate consumption during oxidation of gasoline compounds or degradation due to the interaction with aquifer materials. M increased by > 100% suggesting some mineralization of gasoline compounds during treatment. Mass loading for all the monitored gasoline compounds reduced by 46 to 86% as the inorganic slug crossed the monitoring transect. The cumulative mass discharge across the monitoring transect was 19 to 58% lower than that expected without persulfate injection. After the inorganic injection slug was flushed from the source zone a partial rebound (40 to 80% of baseline levels) of mass discharge of the monitored gasoline compounds was observed. The ensemble of data collected provides insight into the fate and transport of the injected persulfate solution, and the accompanying treatment of a gasoline the source zone.

  8. Soil water nitrate concentrations in giant cane and forest riparian buffer zones

    Science.gov (United States)

    Jon E. Schoonover; Karl W. J. Williard; James J. Zaczek; Jean C. Mangun; Andrew D. Carver

    2003-01-01

    Soil water nitrate concentrations in giant cane and forest riparian buffer zones along Cypress Creek in southern Illinois were compared to determine if the riparian zones were sources or sinks for nitrogen in the rooting zone. Suction lysimeters were used to collect soil water samples from the lower rooting zone in each of the two vegetation types. The cane riparian...

  9. Vapor Intrusion Estimation Tool for Unsaturated Zone Contaminant Sources. User’s Guide

    Science.gov (United States)

    2016-08-30

    estimation process when applying the tool. The tool described here is focused on vapor-phase diffusion from the current vadose zone source , and is not...from the current defined vadose zone source ). The estimated soil gas contaminant concentration obtained from the pre-modeled scenarios for a building...need a full site-specific numerical model to assess the impacts beyond the current vadose zone source . 35 5.0 References Brennan, R.A., N

  10. Riparian zone controls on base cation concentrations in boreal streams

    Science.gov (United States)

    Ledesma, J. L. J.; Grabs, T.; Futter, M. N.; Bishop, K. H.; Laudon, H.; Köhler, S. J.

    2013-01-01

    Forest riparian zones are a major in control of surface water quality. Base cation (BC) concentrations, fluxes, and cycling in the riparian zone merit attention because of increasing concern of negative consequences for re-acidification of surface waters from future climate and forest harvesting scenarios. We present a two-year study of BC and silica (Si) flow-weighted concentrations from 13 riparian zones and 14 streams in a boreal catchment in northern Sweden. The Riparian Flow-Concentration Integration Model (RIM) was used to estimate riparian zone flow-weighted concentrations and tested to predict the stream flow-weighted concentrations. Spatial variation in BC and Si concentrations as well as in flow-weighted concentrations was related to differences in Quaternary deposits, with the largest contribution from lower lying silty sediments and the lowest contribution from wetland areas higher up in the catchment. Temporal stability in the concentrations of most elements, a remarkably stable Mg / Ca ratio in the soil water and a homogeneous mineralogy suggest that the stable patterns found in the riparian zones are a result of distinct mineralogical upslope groundwater signals integrating the chemical signals of biological and chemical weathering. Stream water Mg / Ca ratio indicates that the signal is subsequently maintained in the streams. RIM gave good predictions of Ca, Mg, and Na flow-weighted concentrations in headwater streams. The difficulty in modelling K and Si suggests a stronger biogeochemical influence on these elements. The observed chemical dilution effect with flow in the streams was related to variation in groundwater levels and element concentration profiles in the riparian zones. This study provides a first step toward specific investigations of the vulnerability of riparian zones to changes induced by forest management or climate change, with focus on BC or other compounds.

  11. Delineation of seismic source zones based on seismicity parameters ...

    Indian Academy of Sciences (India)

    these source zones were evaluated and were used in the hazard evaluation. ... seismic sources, linear and areal, were considered in the present study to model the seismic sources in the ..... taken as an authentic reference manual for iden-.

  12. Modeling Degradation Product Partitioning in Chlorinated-DNAPL Source Zones

    Science.gov (United States)

    Boroumand, A.; Ramsburg, A.; Christ, J.; Abriola, L.

    2009-12-01

    Metabolic reductive dechlorination degrades aqueous phase contaminant concentrations, increasing the driving force for DNAPL dissolution. Results from laboratory and field investigations suggest that accumulation of cis-dichloroethene (cis-DCE) and vinyl chloride (VC) may occur within DNAPL source zones. The lack of (or slow) degradation of cis-DCE and VC within bioactive DNAPL source zones may result in these dechlorination products becoming distributed among the solid, aqueous, and organic phases. Partitioning of cis-DCE and VC into the organic phase may reduce aqueous phase concentrations of these contaminants and result in the enrichment of these dechlorination products within the non-aqueous phase. Enrichment of degradation products within DNAPL may reduce some of the advantages associated with the application of bioremediation in DNAPL source zones. Thus, it is important to quantify how partitioning (between the aqueous and organic phases) influences the transport of cis-DCE and VC within bioactive DNAPL source zones. In this work, abiotic two-phase (PCE-water) one-dimensional column experiments are modeled using analytical and numerical methods to examine the rate of partitioning and the capacity of PCE-DNAPL to reversibly sequester cis-DCE. These models consider aqueous-phase, nonaqueous phase, and aqueous plus nonaqueous phase mass transfer resistance using linear driving force and spherical diffusion expressions. Model parameters are examined and compared for different experimental conditions to evaluate the mechanisms controlling partitioning. Biot number, a dimensionless number which is an index of the ratio of the aqueous phase mass transfer rate in boundary layer to the mass transfer rate within the NAPL, is used to characterize conditions in which either or both processes are controlling. Results show that application of a single aqueous resistance is capable to capture breakthrough curves when DNAPL is distributed in porous media as low

  13. Obsidian sources of the Coromandel Volcanic Zone, nortthern New Zealand

    International Nuclear Information System (INIS)

    Moore, P.R.

    2013-01-01

    The Coromandel Volcanic Zone includes nine geographically discrete obsidian sources (Fanal, Awana, Te Ahumata, Cooks Beach, Hahei, Tairua, Whangamata, Maratoto and Waihi). Each has a distinctive chemical composition, and some can also be differentiated on the basis of visual characteristics of the obsidian. Chemically, the three northern sources (Fanal, Awana, Te Ahumata), constituting the 'Great Barrier Group', are distinguished by high Rb concentrations and a high Rb/Sr ratio. Obsidian from six of the sources is known to have been utilized by pre-European Maori for the manufacture of flake tools, but at present there is no evidence for exploitation of the Awana, Maratoto and Tairua deposits. (author). 54 refs., 5 figs., 2 tabs.

  14. Ionization dual-zone static detector having single radioactive source

    International Nuclear Information System (INIS)

    Ried, L. Jr.; Wade, A.L.

    1977-01-01

    This ionization detector or combustion product detector includes a single radioactive source located in an ionization chamber, and the ionization chamber includes portions comprising a reference zone and a signal zone. Electrical circuitry connected to the reference and signal zones provides an output signal directly related to changes in voltages across the signal zone in relation to the amount of particulates of combustion present in the ionization chamber

  15. Delineation of seismic source zones based on seismicity parameters ...

    Indian Academy of Sciences (India)

    In the present study, an attempt has been made to delineate seismic source zones in the study area (south India) based on the seismicity parameters. Seismicity parameters and the maximum probable earthquake for these source zones were evaluated and were used in the hazard evaluation. The probabilistic evaluation of ...

  16. Revealing source signatures in ambient BTEX concentrations

    International Nuclear Information System (INIS)

    Zalel, Amir; Yuval; Broday, David M.

    2008-01-01

    Management of ambient concentrations of Volatile Organic Compounds (VOCs) is essential for maintaining low ozone levels in urban areas where its formation is under a VOC-limited regime. The significant decrease in traffic-induced VOC emissions in many developed countries resulted in relatively comparable shares of traffic and non-traffic VOC emissions in urban airsheds. A key step for urban air quality management is allocating ambient VOC concentrations to their pertinent sources. This study presents an approach that can aid in identifying sources that contribute to observed BTEX concentrations in areas characterized by low BTEX concentrations, where traditional source apportionment techniques are not useful. Analysis of seasonal and diurnal variations of ambient BTEX concentrations from two monitoring stations located in distinct areas reveal the possibility to identify source categories. Specifically, the varying oxidation rates of airborne BTEX compounds are used to allocate contributions of traffic emissions and evaporative sources to observed BTEX concentrations. - BTEX sources are identified from temporal variations of ambient concentration

  17. Soil Heavy Metal Concentration Patterns at Two Speed Zones along ...

    African Journals Online (AJOL)

    Soil Heavy Metal Concentration Patterns at Two Speed Zones along the Gaborone- Tlokweng Border Post Highway, Southeast Botswana. ... Since 1988 Botswana has been experiencing an unprecedented increase in vehicular traffic which is suspected to be having contamination effects on soils along heavily used roads ...

  18. Sources of Magmatic Volatiles Discharging from Subduction Zone Volcanoes

    Science.gov (United States)

    Fischer, T.

    2001-05-01

    Subduction zones are locations of extensive element transfer from the Earth's mantle to the atmosphere and hydrosphere. This element transfer is significant because it can, in some fashion, instigate melt production in the mantle wedge. Aqueous fluids are thought to be the major agent of element transfer during the subduction zone process. Volatile discharges from passively degassing subduction zone volcanoes should in principle, provide some information on the ultimate source of magmatic volatiles in terms of the mantle, the crust and the subducting slab. The overall flux of volatiles from degassing volcanoes should be balanced by the amount of volatiles released from the mantle wedge, the slab and the crust. Kudryavy Volcano, Kurile Islands, has been passively degassing at 900C fumarole temperatures for at least 40 years. Extensive gas sampling at this basaltic andesite cone and application of CO2/3He, N2/3He systematics in combination with C and N- isotopes indicates that 80% of the CO2 and approximately 60% of the N 2 are contributed from a sedimentary source. The mantle wedge contribution for both volatiles is, with 12% and 17% less significant. Direct volatile flux measurements from the volcano using the COSPEC technique in combination with direct gas sampling allows for the calculation of the 3He flux from the volcano. Since 3He is mainly released from the astenospheric mantle, the amount of mantle supplying the 3He flux can be determined if initial He concentrations of the mantle melts are known. The non-mantle flux of CO2 and N2 can be calculated in similar fashion. The amount of non-mantle CO2 and N2 discharging from Kudryavy is balanced by the amount of CO2 and N2 subducted below Kudryavy assuming a zone of melting constrained by the average spacing of the volcanoes along the Kurile arc. The volatile budget for Kudryavy is balanced because the volatile flux from the volcano is relatively small (75 t/day (416 Mmol/a) SO2, 360 Mmol/a of non-mantle CO2 and

  19. Breathing zone concentrations of methylmethacrylate monomer during joint replacement operations

    DEFF Research Database (Denmark)

    Darre, E; Jørgensen, L G; Vedel, P

    1992-01-01

    By use of a methylmethacrylate (MMA) Dräger tube and bellow bump, the breathing zone concentrations of MMA monomer were measured for the operating surgeon during cementation of the components of hip and knee joint prostheses. The highest recordings (50-100 p.p.m.) were encountered during cementat...... cementation of the acetabular cups with conventional polymethylmethacrylate cement. Such exposure could be eliminated by the use of personal protection equipment, local punctual field suction or change to a MMA/n-decylmethacrylate/isobornylmethacrylate bone cement....

  20. Source zone remediation by zero valent iron technologies

    DEFF Research Database (Denmark)

    Fjordbøge, Annika Sidelmann

    at a fifth of these contaminated sites. These source zones pose a serious threat to soil and groundwater quality. Remediation of the heterogeneous source zones is challenging due to irregular downwards migration patterns in the subsurface, low aqueous solubility and matrix diffusion. To protect the soil...... and groundwater resources from long-term deterioration, the development of in situ technologies suitable for remediation of DNAPL is warranted. Currently, an array of aggressive in situ remediation technologies remediation exists. These technologies may be suitable under various site specific conditions; however......, most of them are limited by subsurface heterogeneities and/or the risk of inadvertent DNAPL displacement during field application. This thesis presents the results of an investigation of the potential for remediation of chlorinated solvent source zones by emerging zero valent iron (ZVI) based...

  1. Investigating the influence of DNAPL spill characteristics on source zone architecture and mass removal in pool-dominated source zones

    Science.gov (United States)

    Wallace, K. A.; Abriola, L.; Chen, M.; Ramsburg, A.; Pennell, K. D.; Christ, J.

    2009-12-01

    Multiphase, compositional simulators were employed to investigate the spill characteristics and subsurface properties that lead to pool-dominated, dense non-aqueous phase liquid (DNAPL) source zone architectures. DNAPL pools commonly form at textural interfaces where low permeability lenses restrict the vertical migration of DNAPL, allowing for DNAPL to accumulate, reaching high saturation. Significant pooling has been observed in bench-scale experiments and field settings. However, commonly employed numerical simulations rarely predict the pooling suspected in the field. Given the importance of pooling on the efficacy of mass recovery and the down-gradient contaminant signal, it is important to understand the predominant factors affecting the creation of pool-dominated source zones and their subsequent mass discharge. In this work, contaminant properties, spill characteristics and subsurface permeability were varied to investigate the factors contributing to the development of a pool-dominated source zone. DNAPL infiltration and entrapment simulations were conducted in two- and three-dimensional domains using the University of Texas Chemical Compositional (UTCHEM) simulator. A modified version of MT3DMS was then used to simulate DNAPL dissolution and mass discharge. Numerical mesh size was varied to investigate the importance of numerical model parameters on simulations results. The temporal evolution of commonly employed source zone architecture metrics, such as the maximum DNAPL saturation, first and second spatial moments, and fraction of DNAPL mass located in pools, was monitored to determine how the source zone architecture evolved with time. Mass discharge was monitored to identify the link between source zone architecture and down-gradient contaminant flux. Contaminant characteristics and the presence of extensive low permeability lenses appeared to have the most influence on the development of a pool-dominated source zone. The link between DNAPL mass

  2. Thin-source concentration dependent diffusion

    International Nuclear Information System (INIS)

    Eng, G.

    1978-01-01

    The diffusion of (Ca ++ ) in NaCl has been measured for various diffusion times and for the temperature range (575 0 to 775 0 C), using a thin-source of 45 Ca tracer, rectangular geometry, and serial sectioning. The pre-diffusion surface concentration was approximately 3 x 10 16 (Ca)-atoms/cm 2 , which, for an average penetration depth of 100 to 300 μm, produces a maximum (post-diffusion) impurity concentration comparable to or greater than the intrinsic cation vacancy concentration. The high-temperature function closely matches the D 0 (T) function obtained from low impurity concentration experiments. The lower-temperature function, combined with the sudden failure of the D(C) = D 0 (1 + [C] + 0.5[C] 2 ) function at these lower temperatures, indicates the onset of a second diffusion process, one which would operate only at extremely high impurity concentrations. This low-temperature behavior is shown to be consistent with a breakdown of the conditions assumed for vacancy equilibrium

  3. Characterization of DNAPL Source Zone Architecture and Prediction of Associated Plume Response: Progress and Perspectives

    Science.gov (United States)

    Abriola, L. M.; Pennell, K. D.; Ramsburg, C. A.; Miller, E. L.; Christ, J.; Capiro, N. L.; Mendoza-Sanchez, I.; Boroumand, A.; Ervin, R. E.; Walker, D. I.; Zhang, H.

    2012-12-01

    It is now widely recognized that the distribution of contaminant mass will control both the evolution of aqueous phase plumes and the effectiveness of many source zone remediation technologies at sites contaminated by dense nonaqueous phase liquids (DNAPLs). Advances in the management of sites containing DNAPL source zones, however, are currently hampered by the difficulty associated with characterizing subsurface DNAPL 'architecture'. This presentation provides an overview of recent research, integrating experimental and mathematical modeling studies, designed to improve our ability to characterize DNAPL distributions and predict associated plume response. Here emphasis is placed on estimation of the most information-rich DNAPL architecture metrics, through a combination of localized in situ tests and more readily available plume transect concentration observations. Estimated metrics will then serve as inputs to an upscaled screening model for prediction of long term plume response. Machine learning techniques were developed and refined to identify a variety of source zone metrics and associated confidence intervals through the processing of down gradient concentration data. Estimated metrics include the volumes and volume percentages of DNAPL in pools and ganglia, as well as their ratio (pool fraction). Multiphase flow and transport simulations provided training data for model development and assessment that are representative of field-scale DNAPL source zones and their evolving plumes. Here, a variety of release and site heterogeneity (sequential Gaussian permeability) conditions were investigated. Push-pull tracer tests were also explored as a means to provide localized in situ observations to refine these metric estimates. Here, two-dimensional aquifer cell experiments and mathematical modeling were used to quantify upscaled interphase mass transfer rates and the interplay between injection and extraction rates, local source zone architecture, and tracer

  4. Evaluation of Long-term Performance of Enhanced Anaerobic Source Zone Bioremediation using mass flux

    Science.gov (United States)

    Haluska, A.; Cho, J.; Hatzinger, P.; Annable, M. D.

    2017-12-01

    Chlorinated ethene DNAPL source zones in groundwater act as potential long term sources of contamination as they dissolve yielding concentrations well above MCLs, posing an on-going public health risk. Enhanced bioremediation has been applied to treat many source zones with significant promise, but long-term sustainability of this technology has not been thoroughly assessed. This study evaluated the long-term effectiveness of enhanced anaerobic source zone bioremediation at chloroethene contaminated sites to determine if the treatment prevented contaminant rebound and removed NAPL from the source zone. Long-term performance was evaluated based on achieving MCL-based contaminant mass fluxes in parent compound concentrations during different monitoring periods. Groundwater concertation versus time data was compiled for 6-sites and post-remedial contaminant mass flux data was then measured using passive flux meters at wells both within and down-gradient of the source zone. Post-remedial mass flux data was then combined with pre-remedial water quality data to estimate pre-remedial mass flux. This information was used to characterize a DNAPL dissolution source strength function, such as the Power Law Model and the Equilibrium Stream tube model. The six-sites characterized for this study were (1) Former Charleston Air Force Base, Charleston, SC; (2) Dover Air Force Base, Dover, DE; (3) Treasure Island Naval Station, San Francisco, CA; (4) Former Raritan Arsenal, Edison, NJ; (5) Naval Air Station, Jacksonville, FL; and, (6) Former Naval Air Station, Alameda, CA. Contaminant mass fluxes decreased for all the sites by the end of the post-treatment monitoring period and rebound was limited within the source zone. Post remedial source strength function estimates suggest that decreases in contaminant mass flux will continue to occur at these sites, but a mass flux based on MCL levels may never be exceeded. Thus, site clean-up goals should be evaluated as order

  5. Potential of arid zone vegetation as a source of substrates

    Energy Technology Data Exchange (ETDEWEB)

    Bassham, J.A.

    1977-11-01

    Three aspects of the potential of vegetation in arid zones as a source of substrates are discussed. The first includes the limitations on efficiency of conversion of solar energy to the stored chemical energy of biomass in green plants, and the subsequent biochemical pathways of carbon dioxide fixation and biosynthesis. Second is the potential of plants endogenous to arid zones. Finally, the use of covered agriculture or controlled environmental agriculture (CEA) is considered both in its present form and in terms of possible extenion to the large scale production of stable crops. (JGB)

  6. Water sources accessed by arid zone riparian trees in highly saline environments, Australia.

    Science.gov (United States)

    Costelloe, Justin F; Payne, Emily; Woodrow, Ian E; Irvine, Elizabeth C; Western, Andrew W; Leaney, Fred W

    2008-05-01

    The flow regimes of arid zone rivers are often highly variable, and shallow groundwater in the alluvial aquifers can be very saline, thus constraining the availability and quality of the major water sources available to riparian trees-soil water, shallow groundwater and stream water. We have identified water sources and strategies used by riparian trees in more highly saline and arid conditions than previously studied for riparian trees of arid zone rivers. Our research focused on the riparian species Eucalyptus coolabah, one of the major riparian trees of ephemeral arid zone rivers in Australia. The water sources available to this riparian tree were examined using delta(18)O isotope data from xylem, soil water, groundwater and surface water. Additionally, soil chloride and matric potential data were used to infer zones of water availability for root uptake. Despite the saline conditions, the trees used a mixture of soil water and groundwater sources, but they did not use surface water directly. The study identified three strategies used to cope with typically high groundwater and soil water salinities. Firstly, the trees preferentially grow in zones of most frequent flushing by infiltrating streamflow, such as the bank-tops of channels. Secondly, the trees limit water use by having low transpiration rates. Thirdly, the trees are able to extract water at very low osmotic potentials, with water uptake continuing at chloride concentrations of at least 20,000-30,000 mg L(-1).

  7. Effects of watershed and riparian zone characteristics on nutrient concentrations in the River Scheldt Basin

    Directory of Open Access Journals (Sweden)

    J. Meynendonckx

    2006-01-01

    Full Text Available The relative influence of a set of watershed characteristics on surface water nutrient concentrations was examined in 173 watersheds within two subcatchments (Upper-Scheldt and Nete of the River Scheldt Basin (Flanders, Belgium. Each watershed was described by seasonal rainfall, discharge loading of point sources, morphological characteristics (area, average slope, drainage density, elongation, land use and soil properties (soil texture and drainage. Partial regression analysis revealed that soil drainage variables had the strongest influence on nutrient concentrations. Additional influence was exerted by land use and point source loading variables. Nitrate concentrations were positively correlated with effluent loadings coming from wastewater treatment plants and with the area of agricultural land. Phosphate concentrations were best explained by effluent loadings of industrial point sources and by the area of urban land. Land use close to the river was not a better predictor of nitrate and phosphate concentrations than land use away from the river. This suggests that the mediating impact of riparian zones is rather explained by the hydrologic pathways within the buffer strip.

  8. Oxygenated gasoline release in the unsaturated zone - Part 1: Source zone behavior.

    Science.gov (United States)

    Freitas, Juliana G; Barker, James F

    2011-11-01

    Oxygenates present in gasoline, such as ethanol and MTBE, are a concern in subsurface contamination related to accidental spills. While gasoline hydrocarbon compounds have low solubility, MTBE and ethanol are more soluble, ethanol being completely miscible with water. Consequently, their fate in the subsurface is likely to differ from that of gasoline. To evaluate the fate of gasoline containing oxygenates following a release in the unsaturated zone shielded from rainfall/recharge, a controlled field test was performed at Canadian Forces Base Borden, in Ontario. 200L of a mixture composed of gasoline with 10% ethanol and 4.5% MTBE was released in the unsaturated zone, into a trench 20cm deep, about 32cm above the water table. Based on soil cores, most of the ethanol was retained in the source, above the capillary fringe, and remained there for more than 100 days. Ethanol partitioned from the gasoline to the unsaturated pore-water and was retained, despite the thin unsaturated zone at the site (~35cm from the top of the capillary fringe to ground surface). Due to its lower solubility, most of the MTBE remained within the NAPL as it infiltrated deeper into the unsaturated zone and accumulated with the gasoline on top of the depressed capillary fringe. Only minor changes in the distribution of ethanol were noted following oscillations in the water table. Two methods to estimate the capacity of the unsaturated zone to retain ethanol are explored. It is clear that conceptual models for sites impacted by ethanol-fuels must consider the unsaturated zone. Copyright © 2011 Elsevier B.V. All rights reserved.

  9. Unintentional contaminant transfer from groundwater to the vadose zone during source zone remediation of volatile organic compounds.

    Science.gov (United States)

    Chong, Andrea D; Mayer, K Ulrich

    2017-09-01

    Historical heavy use of chlorinated solvents in conjunction with improper disposal practices and accidental releases has resulted in widespread contamination of soils and groundwater in North America and worldwide. As a result, remediation of chlorinated solvents is required at many sites. For source zone treatment, common remediation strategies include in-situ chemical oxidation (ISCO) using potassium or sodium permanganate, and the enhancement of biodegradation by primary substrate addition. It is well known that these remediation methods tend to generate gas (carbon dioxide (CO 2 ) in the case of ISCO using permanganate, CO 2 and methane (CH 4 ) in the case of bioremediation). Vigorous gas generation in the presence of chlorinated solvents, which are categorized as volatile organic contaminants (VOCs), may cause gas exsolution, ebullition and stripping of the contaminants from the treatment zone. This process may lead to unintentional 'compartment transfer', whereby VOCs are transported away from the contaminated zone into overlying clean sediments and into the vadose zone. To this extent, benchtop column experiments were conducted to quantify the effect of gas generation during remediation of the common chlorinated solvent trichloroethylene (TCE/C 2 Cl 3 H). Both ISCO and enhanced bioremediation were considered as treatment methods. Results show that gas exsolution and ebullition occurs for both remediation technologies. Facilitated by ebullition, TCE was transported from the source zone into overlying clean groundwater and was subsequently released into the column headspace. For the case of enhanced bioremediation, the intermediate degradation product vinyl chloride (VC) was also stripped from the treatment zone. The concentrations measured in the headspace of the columns (TCE ∼300ppm in the ISCO column, TCE ∼500ppm and VC ∼1380ppm in the bioremediation column) indicate that substantial transfer of VOCs to the vadose zone is possible. These findings

  10. Mercury concentration variability in the zooplankton of the southern Baltic coastal zone

    Science.gov (United States)

    Bełdowska, Magdalena; Mudrak-Cegiołka, Stella

    2017-12-01

    Being a toxic element, mercury is introduced to the human organism through the consumption of fish and seafood, which in turn often feed on zooplankton. The bioaccumulation of Hg by zooplankton is an important factor influencing the magnitude of the mercury load introduced with food into the predator organism. Therefore the present article attempts to identify the processes and factors influencing Hg concentration in the zooplankton of the coastal zone, an area where marine organisms - an attractive food source for humans - thrive. This is particularly important in areas where climate changes influence the species composition and quantity of plankton. The studies were carried out on three test sites in the coastal zone of the southern Baltic Sea in the period from December 2011 to May 2013. The obtained results show that the shorting of the winter season is conducive to Hg increase in zooplankton and, consequently, in the trophic chain. High mercury concentrations were measured in genus Synchaeta and Keratella when Mesodinium rubrum were predominant in phytoplankton, while other sources of this metal in the plankton fauna were epilithon, epiphton and microbenthos. This is of particular importance when it comes to sheltered bays and estuaries with low water dynamics.

  11. Uranium Concentration of Contaminated Zone due to the Cover Depth for Self-Disposal

    International Nuclear Information System (INIS)

    Koo, Dae Seo; Sung, Hyun Hee; Kim, Gye Nam; Kim, Seung Soo; Kim, Il Gook; Han, Gyu Seong; Choi, Jong Won

    2016-01-01

    To acquire radiation dose under self disposal from them, the study on decontamination of some uranium contaminated soil and concrete wastes was performed using electrokinetic-electrodialytic. In this study, we evaluated radiation dose due to cover depth on contaminated zone such as uranium contaminated soil and concrete wastes under radiation dose limit using RESRAD Version 6.5. At first, the calculation of the radiation dose on the contaminated zone are carried out. The second, the uranium concentration of contaminated zone due to the cover depth are also analyzed. The uranium contaminated soil and concrete wastes under radiation dose limit by decontaminating them have application to self-disposal of contaminated zone. The area of contaminated zone is 1,500 m"2. The thickness of contaminated zone is 2 m. The length parallel to aquifer flow is 43.702m. The age of the residents on contaminated zone is 15 years old. The period of evaluation on the contaminated zone is from regulation exemption of uranium contaminated soil and concrete wastes till 1,000 years. The calculation of the radiation dose on contaminated zone are carried out. The uranium concentration of contaminated zone due to the cover depth was also analyzed. as the cover depth increases, the uranium concentration has an increasing trend. As the cover depth increases, radiation dose of a person has a decreasing trend. As the cover depth increases, the radiation dose of residents has also a decreasing trend.

  12. Uranium Concentration of Contaminated Zone due to the Cover Depth for Self-Disposal

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Dae Seo; Sung, Hyun Hee; Kim, Gye Nam; Kim, Seung Soo; Kim, Il Gook; Han, Gyu Seong; Choi, Jong Won [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    To acquire radiation dose under self disposal from them, the study on decontamination of some uranium contaminated soil and concrete wastes was performed using electrokinetic-electrodialytic. In this study, we evaluated radiation dose due to cover depth on contaminated zone such as uranium contaminated soil and concrete wastes under radiation dose limit using RESRAD Version 6.5. At first, the calculation of the radiation dose on the contaminated zone are carried out. The second, the uranium concentration of contaminated zone due to the cover depth are also analyzed. The uranium contaminated soil and concrete wastes under radiation dose limit by decontaminating them have application to self-disposal of contaminated zone. The area of contaminated zone is 1,500 m{sup 2}. The thickness of contaminated zone is 2 m. The length parallel to aquifer flow is 43.702m. The age of the residents on contaminated zone is 15 years old. The period of evaluation on the contaminated zone is from regulation exemption of uranium contaminated soil and concrete wastes till 1,000 years. The calculation of the radiation dose on contaminated zone are carried out. The uranium concentration of contaminated zone due to the cover depth was also analyzed. as the cover depth increases, the uranium concentration has an increasing trend. As the cover depth increases, radiation dose of a person has a decreasing trend. As the cover depth increases, the radiation dose of residents has also a decreasing trend.

  13. Mass Transfer Limited Enhanced Bioremediation at Dnapl Source Zones: a Numerical Study

    Science.gov (United States)

    Kokkinaki, A.; Sleep, B. E.

    2011-12-01

    The success of enhanced bioremediation of dense non-aqueous phase liquids (DNAPLs) relies on accelerating contaminant mass transfer from the organic to the aqueous phase, thus enhancing the depletion of DNAPL source zones compared to natural dissolution. This is achieved by promoting biological activity that reduces the contaminant's aqueous phase concentration. Although laboratory studies have demonstrated that high reaction rates are attainable by specialized microbial cultures in DNAPL source zones, field applications of the technology report lower reaction rates and prolonged remediation times. One possible explanation for this phenomenon is that the reaction rates are limited by the rate at which the contaminant partitions from the DNAPL to the aqueous phase. In such cases, slow mass transfer to the aqueous phase reduces the bioavailability of the contaminant and consequently decreases the potential source zone depletion enhancement. In this work, the effect of rate limited mass transfer on bio-enhanced dissolution of DNAPL chlorinated ethenes is investigated through a numerical study. A multi-phase, multi-component groundwater transport model is employed to simulate DNAPL mass depletion for a range of source zone scenarios. Rate limited mass transfer is modeled by a linear driving force model, employing a thermodynamic approach for the calculation of the DNAPL - water interfacial area. Metabolic reductive dechlorination is modeled by Monod kinetics, considering microbial growth and self-inhibition. The model was utilized to identify conditions in which mass transfer, rather than reaction, is the limiting process, as indicated by the bioavailability number. In such cases, reaction is slower than expected, and further increase in the reaction rate does not enhance mass depletion. Mass transfer rate limitations were shown to affect both dechlorination and microbial growth kinetics. The complex dynamics between mass transfer, DNAPL transport and distribution, and

  14. Radon concentration and exhalation rates in building material samples from crushing zone in Shivalik Foot Hills

    International Nuclear Information System (INIS)

    Pundir, Anil; Kamboj, Sunil; Bansal, Vakul; Chauhan, R.P.; Rana, Rajinder Singh

    2012-01-01

    Radon ( 222 Rn) is an inert radioactive gas in the decay chain of uranium ( 238 U). It continuously emanates from soil to the atmosphere. Radon and its progeny are the major natural radioactive sources for the ambient radioactivity on Earth. A number of studies on radon were performed in recent decades focusing on its transport and movement in the atmosphere under different meteorological conditions. Building materials are the main source of radon inside buildings. Some construction materials are naturally more radioactive and removal of such material from the earth's crust and their subsequent use in construction of buildings further enhances the radioactivity level. The knowledge of radioactivity level in the building materials makes us aware about the management, guidelines and standards in construction of buildings. The main objective of the present investigations is to measure radon Concentration and exhalation rates in the samples collected from the Crushing zone of Shivalik foot hills. Different types of materials are being used in Northern part of India for construction of dwellings. For the measurement of radon concentration and its exhalation rates in building materials, LR-115 detectors were exposed in closed plastic canisters for three months. At the end of the exposure time, the detectors were subjected to a chemical etching process in 2.5N NaOH solution. The tracks produced by the alpha particles were observed and counted under an optical Olympus microscope at 600X. The measured track density was converted into radon concentration using a calibration factor. The surface and mass exhalation rates of radon have also been calculated using present data. The results indicate that the radon concentration varies appreciably from sample to sample and they were found to satisfy the safety criteria. There are samples in which radon concentration is higher and may enhance the indoor radiation levels when used as building construction materials. (author)

  15. Modeling the influence of coupled mass transfer processes on mass flux downgradient of heterogeneous DNAPL source zones.

    Science.gov (United States)

    Yang, Lurong; Wang, Xinyu; Mendoza-Sanchez, Itza; Abriola, Linda M

    2018-04-01

    Sequestered mass in low permeability zones has been increasingly recognized as an important source of organic chemical contamination that acts to sustain downgradient plume concentrations above regulated levels. However, few modeling studies have investigated the influence of this sequestered mass and associated (coupled) mass transfer processes on plume persistence in complex dense nonaqueous phase liquid (DNAPL) source zones. This paper employs a multiphase flow and transport simulator (a modified version of the modular transport simulator MT3DMS) to explore the two- and three-dimensional evolution of source zone mass distribution and near-source plume persistence for two ensembles of highly heterogeneous DNAPL source zone realizations. Simulations reveal the strong influence of subsurface heterogeneity on the complexity of DNAPL and sequestered (immobile/sorbed) mass distribution. Small zones of entrapped DNAPL are shown to serve as a persistent source of low concentration plumes, difficult to distinguish from other (sorbed and immobile dissolved) sequestered mass sources. Results suggest that the presence of DNAPL tends to control plume longevity in the near-source area; for the examined scenarios, a substantial fraction (43.3-99.2%) of plume life was sustained by DNAPL dissolution processes. The presence of sorptive media and the extent of sorption non-ideality are shown to greatly affect predictions of near-source plume persistence following DNAPL depletion, with plume persistence varying one to two orders of magnitude with the selected sorption model. Results demonstrate the importance of sorption-controlled back diffusion from low permeability zones and reveal the importance of selecting the appropriate sorption model for accurate prediction of plume longevity. Large discrepancies for both DNAPL depletion time and plume longevity were observed between 2-D and 3-D model simulations. Differences between 2- and 3-D predictions increased in the presence of

  16. Modeling the influence of coupled mass transfer processes on mass flux downgradient of heterogeneous DNAPL source zones

    Science.gov (United States)

    Yang, Lurong; Wang, Xinyu; Mendoza-Sanchez, Itza; Abriola, Linda M.

    2018-04-01

    Sequestered mass in low permeability zones has been increasingly recognized as an important source of organic chemical contamination that acts to sustain downgradient plume concentrations above regulated levels. However, few modeling studies have investigated the influence of this sequestered mass and associated (coupled) mass transfer processes on plume persistence in complex dense nonaqueous phase liquid (DNAPL) source zones. This paper employs a multiphase flow and transport simulator (a modified version of the modular transport simulator MT3DMS) to explore the two- and three-dimensional evolution of source zone mass distribution and near-source plume persistence for two ensembles of highly heterogeneous DNAPL source zone realizations. Simulations reveal the strong influence of subsurface heterogeneity on the complexity of DNAPL and sequestered (immobile/sorbed) mass distribution. Small zones of entrapped DNAPL are shown to serve as a persistent source of low concentration plumes, difficult to distinguish from other (sorbed and immobile dissolved) sequestered mass sources. Results suggest that the presence of DNAPL tends to control plume longevity in the near-source area; for the examined scenarios, a substantial fraction (43.3-99.2%) of plume life was sustained by DNAPL dissolution processes. The presence of sorptive media and the extent of sorption non-ideality are shown to greatly affect predictions of near-source plume persistence following DNAPL depletion, with plume persistence varying one to two orders of magnitude with the selected sorption model. Results demonstrate the importance of sorption-controlled back diffusion from low permeability zones and reveal the importance of selecting the appropriate sorption model for accurate prediction of plume longevity. Large discrepancies for both DNAPL depletion time and plume longevity were observed between 2-D and 3-D model simulations. Differences between 2- and 3-D predictions increased in the presence of

  17. Concentrated flow paths in riparian buffer zones of southern Illinois

    Science.gov (United States)

    R.C. Pankau; J.E. Schoonover; K.W.J. Willard; P.J. Edwards

    2012-01-01

    Riparian buffers in agricultural landscapes should be designed to trap pollutants in overland flow by slowing, filtering, and infiltrating surface runoff entering the buffer via sheet flow. However, observational evidence suggests that concentrated flow is prevalent from agricultural fields. Over time sediment can accumulate in riparian buffers forming berms that...

  18. Advanced Neutron Source Reactor zoning, shielding, and radiological optimization guide

    International Nuclear Information System (INIS)

    Westbrook, J.L.; DeVore, J.R.

    1995-08-01

    In the design of major nuclear facilities, it is important to protect both humans and equipment excessive radiation dose. Past experience has shown that it is very effective to apply dose reduction principles early in the design of a nuclear facility both to specific design features and to the manner of operation of the facility, where they can aid in making the facility more efficient and cost-effective. Since the appropriate choice of radiological controls and practices varies according to the case, each area of the facility must be analyzed for its radiological impact, both by itself and in interactions with other areas. For the Advanced Neutron Source (ANS) project, a large relational database will be used to collect facility information by system and relate it to areas. The database will also hold the facility dose and shielding information as it is produced during the design process. This report details how the ANS zoning scheme was established and how the calculation of doses and shielding are to be done

  19. Calculation of Radioactivity Concentration on Cover Depth of Contaminated Zone for Self-Disposal

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Daeseo; Sung, Hyun-Hee; Kim, Gye-Nam; Kim, Seung-Soo; Kim, Ilgook; Han, Gyu Seong; Choi, Jong-Won [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    We have a lot of uranium contaminated soil and concrete wastes owing to dismantlement of uranium conversion facility. There are several radioactive material disposal methods such as regulation exemption, decontamination and long term storage. It is necessary for us to perform permanent disposal of these wastes. To acquire radiation dose under self-disposal from them, the study on decontamination of some uranium contaminated soil and concrete wastes was performed using electrokinectic-electrodialytic. In this study, we evaluated radiation dose on the cover depth of contaminated zone from the wastes under radiation dose limit using RESRAD Version 6.5. At first, the calculation of the radiation dose on the wastes of contaminated zone are carried out. The second, the cover depth of contaminated zone are analyzed. The application to self-disposal of contaminated zone are also analyzed. To acquire radiation dose under self-disposal from uranium contaminated soil and concrete wastes, we decontaminated some uranium contaminated soil and concrete wastes using electrokinectic-electrodialytic. To perform self-disposal of the quantity (30,000kg) of contaminated zone, the calculating conditions for radiation dose on the cover depth of contaminated zone are as follows. The area of contaminated zone is 10m{sup 2}. The thickness of contaminated zone is 2 m. The cover depth of contaminated zone are analyzed. The application to self-disposal of contaminated zone are also analyzed. Therefore, as the cover depth increases, the uranium concentration has an increasing trend. It realize that the cover depth of contaminated zone is adequate < 2m at the quantity(30,000kg) of contaminated zone. As the cover depth increases, the uranium concentration has a decreasing trend. As the cover depth increases, the radiation dose(residents) has also a decreasing trend.

  20. Concentration of floating biogenic material in convergence zones

    Science.gov (United States)

    Dandonneau, Yves; Menkes, Christophe; Duteil, Olaf; Gorgues, Thomas

    Some organisms that live just below the sea surface (the neuston) are known more as a matter of curiosity than as critical players in biogeochemical cycles. The hypothesis of this work is that their existence implies that they receive some food from an upward flux of organic matter. The behaviour of these organisms and of the associated organic matter, hereafter mentioned as floating biogenic material (FBM) is explored using a global physical-biogeochemical coupled model, in which its generation is fixed to 1% of primary production, and decay rate is of the order of 1 month. The model shows that the distribution of FBM should depart rapidly from that of primary production, and be more sensitive to circulation patterns than to the distribution of primary production. It is trapped in convergence areas, where it reaches concentrations larger by a factor 10 than in divergences, thus enhancing and inverting the contrast between high and low primary productivity areas. Attention is called on the need to better understand the biogeochemical processes in the first meter of the ocean, as they may impact the distribution of food for fishes, as well as the conditions for air-sea exchange and for the interpretation of sea color.

  1. Laboratory test of source encapsulation for decreasing PCB concentrations

    DEFF Research Database (Denmark)

    Kolarik, Barbara; Andersen, Helle Vibeke; Markowicz, Pawel

    2016-01-01

    This study investigates the effect of encapsulation of tertiary PCB sources with PERMASORB™ Adsorber Wallpaper and the surface emissions trap (cTrap) on indoor air concentration of PCBs and on the PCB content in the source. The 40 weeks long laboratory investigation shows reduction of the air...... concentration by approx. 90% for both wallpapers, a level comparable to source removal. The potential for extraction of PCBs from the contaminated materials stays unclear for both wallpapers. The cTrap has shown potential to accumulate PCBs, however the total content of PCB in investigated sources has...... apparently increased. The opposite was observed for the PERMASORB™, where the total PCB content in the sources has decreased, with however only small concentration of PCBs in the wallpaper measured at the end of the experiment....

  2. Rebound of a coal tar creosote plume following partial source zone treatment with permanganate.

    Science.gov (United States)

    Thomson, N R; Fraser, M J; Lamarche, C; Barker, J F; Forsey, S P

    2008-11-14

    The long-term management of dissolved plumes originating from a coal tar creosote source is a technical challenge. For some sites stabilization of the source may be the best practical solution to decrease the contaminant mass loading to the plume and associated off-site migration. At the bench-scale, the deposition of manganese oxides, a permanganate reaction byproduct, has been shown to cause pore plugging and the formation of a manganese oxide layer adjacent to the non-aqueous phase liquid creosote which reduces post-treatment mass transfer and hence mass loading from the source. The objective of this study was to investigate the potential of partial permanganate treatment to reduce the ability of a coal tar creosote source zone to generate a multi-component plume at the pilot-scale over both the short-term (weeks to months) and the long-term (years) at a site where there is >10 years of comprehensive synoptic plume baseline data available. A series of preliminary bench-scale experiments were conducted to support this pilot-scale investigation. The results from the bench-scale experiments indicated that if sufficient mass removal of the reactive compounds is achieved then the effective solubility, aqueous concentration and rate of mass removal of the more abundant non-reactive coal tar creosote compounds such as biphenyl and dibenzofuran can be increased. Manganese oxide formation and deposition caused an order-of-magnitude decrease in hydraulic conductivity. Approximately 125 kg of permanganate were delivered into the pilot-scale source zone over 35 days, and based on mass balance estimates 35% reduction for all monitored compounds except for biphenyl, dibenzofuran and fluoranthene 150 days after treatment, which is consistent with the bench-scale experimental results. Pre- and post-treatment soil core data indicated a highly variable and random spatial distribution of mass within the source zone and provided no insight into the mass removed of any of the

  3. Source contributions to atmospheric fine carbon particle concentrations

    Science.gov (United States)

    Andrew Gray, H.; Cass, Glen R.

    A Lagrangian particle-in-cell air quality model has been developed that facilitates the study of source contributions to atmospheric fine elemental carbon and fine primary total carbon particle concentrations. Model performance was tested using spatially and temporally resolved emissions and air quality data gathered for this purpose in the Los Angeles area for the year 1982. It was shown that black elemental carbon (EC) particle concentrations in that city were dominated by emissions from diesel engines including both on-highway and off-highway applications. Fine primary total carbon particle concentrations (TC=EC+organic carbon) resulted from the accumulation of small increments from a great variety of emission source types including both gasoline and diesel powered highway vehicles, stationary source fuel oil and gas combustion, industrial processes, paved road dust, fireplaces, cigarettes and food cooking (e.g. charbroilers). Strategies for black elemental carbon particle concentration control will of necessity need to focus on diesel engines, while controls directed at total carbon particle concentrations will have to be diversified over a great many source types.

  4. Monitoring well utility in a heterogeneous DNAPL source zone area: Insights from proximal multilevel sampler wells and sampling capture-zone modelling.

    Science.gov (United States)

    McMillan, Lindsay A; Rivett, Michael O; Wealthall, Gary P; Zeeb, Peter; Dumble, Peter

    2018-03-01

    Groundwater-quality assessment at contaminated sites often involves the use of short-screen (1.5 to 3 m) monitoring wells. However, even over these intervals considerable variation may occur in contaminant concentrations in groundwater adjacent to the well screen. This is especially true in heterogeneous dense non-aqueous phase liquid (DNAPL) source zones, where cm-scale contamination variability may call into question the effectiveness of monitoring wells to deliver representative data. The utility of monitoring wells in such settings is evaluated by reference to high-resolution multilevel sampler (MLS) wells located proximally to short-screen wells, together with sampling capture-zone modelling to explore controls upon well sample provenance and sensitivity to monitoring protocols. Field data are analysed from the highly instrumented SABRE research site that contained an old trichloroethene source zone within a shallow alluvial aquifer at a UK industrial facility. With increased purging, monitoring-well samples tend to a flow-weighted average concentration but may exhibit sensitivity to the implemented protocol and degree of purging. Formation heterogeneity adjacent to the well-screen particularly, alongside pump-intake position and water level, influence this sensitivity. Purging of low volumes is vulnerable to poor reproducibility arising from concentration variability predicted over the initial 1 to 2 screen volumes purged. Marked heterogeneity may also result in limited long-term sample concentration stabilization. Development of bespoke monitoring protocols, that consider screen volumes purged, alongside water-quality indicator parameter stabilization, is recommended to validate and reduce uncertainty when interpreting monitoring-well data within source zone areas. Generalised recommendations on monitoring well based protocols are also developed. A key monitoring well utility is their proportionately greater sample draw from permeable horizons constituting

  5. Monitoring well utility in a heterogeneous DNAPL source zone area: Insights from proximal multilevel sampler wells and sampling capture-zone modelling

    Science.gov (United States)

    McMillan, Lindsay A.; Rivett, Michael O.; Wealthall, Gary P.; Zeeb, Peter; Dumble, Peter

    2018-03-01

    Groundwater-quality assessment at contaminated sites often involves the use of short-screen (1.5 to 3 m) monitoring wells. However, even over these intervals considerable variation may occur in contaminant concentrations in groundwater adjacent to the well screen. This is especially true in heterogeneous dense non-aqueous phase liquid (DNAPL) source zones, where cm-scale contamination variability may call into question the effectiveness of monitoring wells to deliver representative data. The utility of monitoring wells in such settings is evaluated by reference to high-resolution multilevel sampler (MLS) wells located proximally to short-screen wells, together with sampling capture-zone modelling to explore controls upon well sample provenance and sensitivity to monitoring protocols. Field data are analysed from the highly instrumented SABRE research site that contained an old trichloroethene source zone within a shallow alluvial aquifer at a UK industrial facility. With increased purging, monitoring-well samples tend to a flow-weighted average concentration but may exhibit sensitivity to the implemented protocol and degree of purging. Formation heterogeneity adjacent to the well-screen particularly, alongside pump-intake position and water level, influence this sensitivity. Purging of low volumes is vulnerable to poor reproducibility arising from concentration variability predicted over the initial 1 to 2 screen volumes purged. Marked heterogeneity may also result in limited long-term sample concentration stabilization. Development of bespoke monitoring protocols, that consider screen volumes purged, alongside water-quality indicator parameter stabilization, is recommended to validate and reduce uncertainty when interpreting monitoring-well data within source zone areas. Generalised recommendations on monitoring well based protocols are also developed. A key monitoring well utility is their proportionately greater sample draw from permeable horizons constituting a

  6. Radon concentration distributions in shallow and deep groundwater around the Tachikawa fault zone.

    Science.gov (United States)

    Tsunomori, Fumiaki; Shimodate, Tomoya; Ide, Tomoki; Tanaka, Hidemi

    2017-06-01

    Groundwater radon concentrations around the Tachikawa fault zone were surveyed. The radon concentrations in shallow groundwater samples around the Tachikawa fault segment are comparable to previous studies. The characteristics of the radon concentrations on both sides of the segment are considered to have changed in response to the decrease in groundwater recharge caused by urbanization on the eastern side of the segment. The radon concentrations in deep groundwater samples collected around the Naguri and the Tachikawa fault segments are the same as those of shallow groundwater samples. However, the radon concentrations in deep groundwater samples collected from the bedrock beside the Naguri and Tachikawa fault segments are markedly higher than the radon concentrations expected from the geology on the Kanto plane. This disparity can be explained by the development of fracture zones spreading on both sides of the two segments. The radon concentration distribution for deep groundwater samples from the Naguri and the Tachikawa fault segments suggests that a fault exists even at the southern part of the Tachikawa fault line. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Recent (2008-10) concentrations and isotopic compositions of nitrate and concentrations of wastewater compounds in the Barton Springs zone, south-central Texas, and their potential relation to urban development in the contributing zone

    Science.gov (United States)

    Mahler, Barbara J.; Musgrove, MaryLynn; Herrington, Chris; Sample, Thomas L.

    2011-01-01

    contributing watersheds. An isotopic composition of nitrate (delta nitrogen–15) greater than 8 per mil in many of the samples indicated there was a contribution of nitrate with a biogenic (human and or animal waste, or both) origin. Wastewater compounds measured in routine samples were detected infrequently (3 percent of cases), and concentrations were very low (less than the method reporting level in most cases). There was no correlation between nitrate concentrations and the frequency of detection of wastewater compounds, indicating that wastewater compounds might be undergoing removal during such processes as infiltration through soil. Three potential sources of biogenic nitrate to the contributing zone were considered: septic systems, land application of treated wastewater, and domesticated dogs and cats. During 2001–10, the estimated densities of septic systems and domesticated dogs and cats (number per acre) increased in the watersheds of all five creeks, and the rate of land application of treated wastewater (gallons per day per acre) increased in the watersheds of Barton, Bear, and Onion Creeks. Considering the timing and location of the increases in the three sources, septic systems were considered a likely source of increased nitrate to Bear Creek; land application of treated wastewater a likely source to Barton, Bear, and Onion Creeks; and domestic dogs and cats a potential source principally to Williamson Creek. The results of this investigation indicate that baseline water quality, in terms of nitrate, has shifted upward between 2001 and 2010, even without any direct discharges of treated wastewater to the creeks.

  8. Global atmospheric concentrations and source strength of ethane

    Science.gov (United States)

    Blake, D. R.; Rowland, F. S.

    1986-01-01

    A study of the variation in ethane (C2H6) concentration between northern and southern latitudes over three years is presented together with a new estimate of its source strength. Ethane concentrations vary from 0.07 to 2 p.p.b.v. (parts per billion by volume) in air samples collected in remote surface locations in the Pacific (latitude 71 N-47 S) in all four seasons between September 1984 and June 1985. The variations are consistent with southerly transport from sources located chiefly in the Northern Hemisphere, further modified by seasonal variations in the strength of the reaction of C2H6 with OH radicals. These global data can be combined with concurrent data for CH4 and the laboratory reaction rates of each with OH to provide an estimate of three months as the average atmospheric lifetime for C2H6 and 13 + or - 3 Mtons for its annual atmospheric release.

  9. Influence of buffer zone concentrations on efficiency in partial filling micellar electrokinetic chromatography.

    Science.gov (United States)

    Michalke, D; Kolb, S; Welsch, T

    2001-05-04

    The potential of counter pressure-moderated partial filling micellar electrokinetic chromatography (PF-MEKC) was investigated in this work. Plate numbers of homologous omega-phenylalcohols were measured in a two-plug PF-MEKC system varying the concentrations and hence the ionic strengths of the background buffer compared to the sodium dodecyl sulfate-containing separation buffer and the counter pressure on the cathodic buffer reservoir. It was observed that plate numbers are strongly influenced by both the buffer concentrations and the counter pressure. Highest plate numbers were obtained with a buffer system where the concentrations are adjusted such that the electroosmotic flow velocities in both zones are equal. Differences in the local electroosmotic flow velocities of the zones caused by different buffer concentrations are responsible for tremendously reduced plate numbers. The efficiency drop is explained in several models by the formation of an intersegmental pressure which produces a parabolically shaped laminar flow component in both zones. Thus, the electroosmotic plug-like flow profile is distorted and the efficiency is reduced. The effect of counter pressure on efficiency turned out to be very complex in dependence on the buffer system applied.

  10. A framework for sourcing of evaporation between saturated and unsaturated zone in bare soil condition

    OpenAIRE

    Balugani, E.; Lubczynski, M.W.; Metselaar, Klaas

    2016-01-01

    Sourcing subsurface evaporation (Ess) into groundwater (Eg) and unsaturated zone (Eu) components has received little scientific attention so far, despite its importance in water management and agriculture. We propose a novel sourcing framework, with its implementation in dedicated post-processing software called SOURCE (used along with the HYDRUS1D model), to study evaporation sourcing dynamics, define quantitatively “shallow” and “deep” water table conditions and test the applicability of wa...

  11. Argon concentration time-series as a tool to study gas dynamics in the hyporheic zone.

    Science.gov (United States)

    Mächler, Lars; Brennwald, Matthias S; Kipfer, Rolf

    2013-07-02

    The oxygen dynamics in the hyporheic zone of a peri-alpine river (Thur, Switzerland), were studied through recording and analyzing the concentration time-series of dissolved argon, oxygen, carbon dioxide, and temperature during low flow conditions, for a period of one week. The argon concentration time-series was used to investigate the physical gas dynamics in the hyporheic zone. Differences in the transport behavior of heat and gas were determined by comparing the diel temperature evolution of groundwater to the measured concentration of dissolved argon. These differences were most likely caused by vertical heat transport which influenced the local groundwater temperature. The argon concentration time-series were also used to estimate travel times by cross correlating argon concentrations in the groundwater with argon concentrations in the river. The information gained from quantifying the physical gas transport was used to estimate the oxygen turnover in groundwater after water recharge. The resulting oxygen turnover showed strong diel variations, which correlated with the water temperature during groundwater recharge. Hence, the variation in the consumption rate was most likely caused by the temperature dependence of microbial activity.

  12. The influence of copper concentration and source on ileal microbiota.

    Science.gov (United States)

    Pang, Y; Patterson, J A; Applegate, T J

    2009-03-01

    Copper is normally supplemented in poultry diets as a growth promotant and antimicrobial. However, there are conflicting reports about the growth benefits and little information about how Cu affects the microbiota in the intestinal tract of poultry. Therefore, in vitro and in vivo experiments were conducted with broilers to determine the effects of Cu source and supplementation on ileal microbiota. The influence of Cu on growth of lactobacilli and Escherichia coli in media inoculated with ileal contents was determined in the first study. When Cu sulfate pentahydrate was supplemented to the cultures, quadratic increases in lactobacilli to graded concentrations of Cu up to 125 mg/kg and quadratic decreases in E. coli up to 250 mg/kg of Cu were observed after 24 h of incubation at 37 degrees C. However, when tribasic Cu chloride (TBCC) was supplemented, neither linear nor quadratic responses to graded concentrations of dietary Cu were observed on number of lactobacilli or number of E. coli. The effects of Cu and Cu source on ileal microbiota and growth performance in broiler chickens were determined in the second study. Bird performance was not affected by Cu source or concentration. The bacterial culture enumeration results revealed that supplementation with 187.5 mg/kg of Cu from Cu sulfate pentahydrate and TBCC had no effect on number of ileal lactobacilli of birds. The denaturing gradient gel electrophoresis analyses of ileal microbial communities revealed that neither Cu supplementation nor source had effects on the number of bacterial species predominant in the ileal digesta or associated with the ileal mucosa. Supplementation with TBCC supplementation significantly increased the similarity coefficients of microbiota in the ileal mucosa compared with cross-products of all individuals. This suggests that TBCC may alter the intestinal microbiota, yet this shift had no effect on bird performance.

  13. A framework for sourcing of evaporation between saturated and unsaturated zone in bare soil condition

    NARCIS (Netherlands)

    Balugani, E.; Lubczynski, M.W.; Metselaar, Klaas

    2016-01-01

    Sourcing subsurface evaporation (Ess) into groundwater (Eg) and unsaturated zone (Eu) components has received little scientific attention so far, despite its importance in water management and agriculture. We propose a novel sourcing framework, with its

  14. A framework for sourcing of evaporation between saturated and unsaturated zone in bare soil condition

    NARCIS (Netherlands)

    Balugani, E.; Lubczynski, M.; Metselaar, K.A.

    2016-01-01

    Sourcing subsurface evaporation (Ess) into groundwater (Eg) and unsaturated zone (Eu) components has received little scientific attention so far, despite its importance in water management and agriculture. We propose a novel sourcing framework, with its implementation in dedicated post-processing

  15. Integrated Characterization of DNAPL Source Zone Architecture in Clay Till and Limestone Bedrock

    DEFF Research Database (Denmark)

    Broholm, Mette Martina; Janniche, Gry Sander; Fjordbøge, Annika Sidelmann

    2014-01-01

    Background/Objectives. Characterization of dense non-aqueous phase liquid (DNAPL) source zone architecture is essential to develop accurate site specific conceptual models, delineate and quantify contaminant mass, perform risk assessment, and select and design remediation alternatives. The activi......Background/Objectives. Characterization of dense non-aqueous phase liquid (DNAPL) source zone architecture is essential to develop accurate site specific conceptual models, delineate and quantify contaminant mass, perform risk assessment, and select and design remediation alternatives...... innovative investigation methods and characterize the source zone hydrogeology and contamination to obtain an improved conceptual understanding of DNAPL source zone architecture in clay till and bryozoan limestone bedrock. Approach/Activities. A wide range of innovative and current site investigative tools...... for direct and indirect documentation and/or evaluation of DNAPL presence were combined in a multiple lines of evidence approach. Results/Lessons Learned. Though no single technique was sufficient for characterization of DNAPL source zone architecture, the combined use of membrane interphase probing (MIP...

  16. Dissolved oxygen concentration profiles in the hyporheic zone through the use of a high density fiber optic measurement network

    Science.gov (United States)

    Reeder, W. J.; Quick, A. M.; Farrell, T. B.; Benner, S. G.; Feris, K. P.; Tonina, D.

    2013-12-01

    The hyporheic zone (HZ) is a potentially important source of the potent greenhouse gas, nitrous oxide (N2O); stream processes may account for up to 10% of global anthropogenic N2O emissions. However, mechanistic understanding and predictive quantification of this gas flux is hampered by complex temporally and spatially variable interactions between flow dynamics and biogeochemical processes. Reactive inorganic nitrogen (Nr) is typically present at low concentrations in natural stream waters, but many rural and urban streams suffer from an excess of Nr, typically in the form of ammonium (NH4+) and nitrate (NO3-). These reactive species are either assimilated by living biomass or transformed by microbial processes. The two primary microbial transformations of Nr are nitrification (NH4+ to NO3-) and denitrification (NO3- to N2). Denitrification, which occurs almost exclusively in the anoxic zone of the HZ, permanently removes between 30-70% of all Nr entering streams, other mechanisms may retain nitrogen. The mass transport of reactive species (i.e. O2, NO3- and N2O) by hyporheic flow strongly influences reaction rates, residence times, and subsequent N2O flux. By extension, stream flow and channel morphology presumably control, and may be effective predictors of, N2O generation rates. By recreating the stream processes in the University of Idaho flume, we are able to control the bed morphology, fluxes and residence times through the HZ and concentrations of Nr from exogenous (stream water) and endogenous (organic material in the streambed) sources. For the present experiment, the flume was divided into three streams, each with different morphologies (3, 6 and 9cm dunes) and all using the same source water. Stream water for this first experimental phase had no significant loading of Nr. As such, all reaction products were the result of endogenous sources of Nr. To measure dissolved oxygen (DO) concentrations we deployed 120 channels of a novel, fiber-optic optode

  17. ZVI-Clay remediation of a chlorinated solvent source zone, Skuldelev, Denmark: 1. Site description and contaminant source mass reduction

    DEFF Research Database (Denmark)

    Fjordbøge, Annika Sidelmann; Riis, Charlotte; Christensen, Anders G.

    2012-01-01

    Field investigations on the effects of ZVI-Clay soil mixing were conducted at a small DNAPL source zone with PCE as the parent compound. In a one-year monitoring program, soil samples were collected at three horizontal sampling planes (2.5, 5.0 and 7.5m bgs.). PCE was found to have a pseudo first...

  18. Contaminant Flux Reduction Barriers for Managing Difficult-to-Treat Source Zones in Unconsolidated Media

    Science.gov (United States)

    2017-06-20

    estimated viscosity of 3-4 cP.  Solutions-IES Novel Silica Gel/Veg-Oil Grout: 5 wt- % of emulsified vegetable oil (EVO), 10 wt-% of sodium...site must have a lower low permeability unit such as a clay to prevent up flow; and a four sided barrier is recommended (three sided barriers are...depth to groundwater (ង ft)  Transmissive zone preferably with an underlying clay layer  Good accessibility to source zone  Availability of

  19. Fresnel zone plate imaging of a 252Cf spontaneous fission source

    International Nuclear Information System (INIS)

    Stalker, K.T.; Hessel, K.R.

    1976-11-01

    The feasibility of coded aperture imaging for nuclear fuel motion monitoring is shown using Cf 252 spontaneous fission source. The theory of coded aperture imaging for Fresnel zone plate apertures is presented and design considerations for zone plate construction are discussed. Actual images are obtained which demonstrate a transverse resolution of 1.7 mm and a tomographic resolution of 1.5 millimeters. The capability of obtaining images through 12.7 mm of stainless steel is also shown

  20. Heavy metal concentrations and distribution in surface soils of the Bassa Industrial Zone 1, Douala, Cameroon

    International Nuclear Information System (INIS)

    Asaah, Victor A.; Abimbola, Akinlolu F.; Suh, Cheo E.

    2006-01-01

    Partial extraction was carried out on 33 soil samples collected from the Bassa Industrial Zone 1, Douala, Cameroon. From the samples analyzed the following metal concentrations (range) were obtained (in ppm): Ag (0-1.3), As (0-64), Cd(0-7.3), Co(0-31), Cr(34-423), Cu(12-909), Mn(55-3282), Mo(0-81.6), Ni(9-284), Pb (0-3320), Sb (0-30), Sc (0.6-7.5), V (26-110), Zn (30-3782) and Fe (in wt%) (1.50-47.31). Results obtained reveal background and anomalous populations for most of the metals except Sc and V, which have only background populations. Multi-element geochemical anomalies occur within the vicinity of industries, waste dump sites, metal workshops and mechanical workshops. R-mode factor analysis reveals three element associations and two singular elements (As, Cd) accounting for 94% of the total data variance. The three associations are: Ag-Cu-Cr-Fe-Mn-Mo-Ni-Sb; Co-Cu-Pb-Sb-Zn and Sc-V. The geoaccumulation indices show that soils in the Bassa Industrial Zone are moderately to very highly pollute. These metal-laden soils constitute a major health risk to the local population and a cause for concern. This study successfully relates the concentration and distribution of toxic metals in the soils of Bassa Industrial Zone to urban effluents generated mainly from industrial activities. (author)

  1. [Indoor volatile organic compounds: concentrations, sources, variation factors].

    Science.gov (United States)

    Palot, A; Charpin-Kadouch, C; Ercoli, J; Charpin, D

    2008-06-01

    Volatile organic compounds (V.O.C.) are part of urban air pollution and are also generated indoors from cleaning and maintenance products. VOC measurements are, on average, 10 times higher within homes than outside. Results of the national survey led by the Observatoire National de la Qualité de l'Air Intérieur demonstrated that up to 25% of French homes have very high or high concentrations of VOC. Indoor levels depend mainly on indoor sources. Aldehydes are included in many everyday life products. VOC originate from various household decorating and cleaning products. Some products are less detrimental to the environment and health and have special labelling. Indoor VOC levels also depend on the rate of air exchange and on household characteristics such as indoor temperature and humidity, age of the building, presence of smokers, and communication with a garage. The public may participate in maintaining good indoor air quality and the authorities should also improve regulations. VOC are part of everyday air pollution. Their sources and concentrations should be better monitored.

  2. Assessing the joint impact of DNAPL source-zone behavior and degradation products on the probabilistic characterization of human health risk

    Science.gov (United States)

    Henri, Christopher V.; Fernàndez-Garcia, Daniel; de Barros, Felipe P. J.

    2016-02-01

    The release of industrial contaminants into the subsurface has led to a rapid degradation of groundwater resources. Contamination caused by Dense Non-Aqueous Phase Liquids (DNAPLs) is particularly severe owing to their limited solubility, slow dissolution and in many cases high toxicity. A greater insight into how the DNAPL source zone behavior and the contaminant release towards the aquifer impact human health risk is crucial for an appropriate risk management. Risk analysis is further complicated by the uncertainty in aquifer properties and contaminant conditions. This study focuses on the impact of the DNAPL release mode on the human health risk propagation along the aquifer under uncertain conditions. Contaminant concentrations released from the source zone are described using a screening approach with a set of parameters representing several scenarios of DNAPL architecture. The uncertainty in the hydraulic properties is systematically accounted for by high-resolution Monte Carlo simulations. We simulate the release and the transport of the chlorinated solvent perchloroethylene and its carcinogenic degradation products in randomly heterogeneous porous media. The human health risk posed by the chemical mixture of these contaminants is characterized by the low-order statistics and the probability density function of common risk metrics. We show that the zone of high risk (hot spot) is independent of the DNAPL mass release mode, and that the risk amplitude is mostly controlled by heterogeneities and by the source zone architecture. The risk is lower and less uncertain when the source zone is formed mostly by ganglia than by pools. We also illustrate how the source zone efficiency (intensity of the water flux crossing the source zone) affects the risk posed by an exposure to the chemical mixture. Results display that high source zone efficiencies are counter-intuitively beneficial, decreasing the risk because of a reduction in the time available for the production

  3. Preliminary assessment of the nuclide migration from the activation zone around the proposed Spallation Neutron Source facility

    International Nuclear Information System (INIS)

    Dole, L.R.

    1998-09-01

    The purpose of this study is to investigate the potential impacts of migrating radionuclides from the activation zone around the proposed Spallation Neutron Source (SNS). Using conservatively high estimates of the potential inventory of radioactive activation products that could form in the proposed compacted-soil shield berm around an SNS facility on the Oak Ridge Reservation (ORR), a conservative, simplified transport model was used to estimate the potential worst-case concentrations of the 12 long-lived isotopes in the groundwater under a site with the hydrologic characteristics of the ORR

  4. Preliminary assessment of the nuclide migration from the activation zone around the proposed Spallation Neutron Source facility

    Energy Technology Data Exchange (ETDEWEB)

    Dole, L.R.

    1998-09-01

    The purpose of this study is to investigate the potential impacts of migrating radionuclides from the activation zone around the proposed Spallation Neutron Source (SNS). Using conservatively high estimates of the potential inventory of radioactive activation products that could form in the proposed compacted-soil shield berm around an SNS facility on the Oak Ridge Reservation (ORR), a conservative, simplified transport model was used to estimate the potential worst-case concentrations of the 12 long-lived isotopes in the groundwater under a site with the hydrologic characteristics of the ORR.

  5. Active/passive microwave sensor comparison of MIZ-ice concentration estimates. [Marginal Ice Zone (MIZ)

    Science.gov (United States)

    Burns, B. A.; Cavalieri, D. J.; Keller, M. R.

    1986-01-01

    Active and passive microwave data collected during the 1984 summer Marginal Ice Zone Experiment in the Fram Strait (MIZEX 84) are used to compare ice concentration estimates derived from synthetic aperture radar (SAR) data to those obtained from passive microwave imagery at several frequencies. The comparison is carried out to evaluate SAR performance against the more established passive microwave technique, and to investigate discrepancies in terms of how ice surface conditions, imaging geometry, and choice of algorithm parameters affect each sensor. Active and passive estimates of ice concentration agree on average to within 12%. Estimates from the multichannel passive microwave data show best agreement with the SAR estimates because the multichannel algorithm effectively accounts for the range in ice floe brightness temperatures observed in the MIZ.

  6. Can Concentration - Discharge Relationships Diagnose Material Source During Extreme Events?

    Science.gov (United States)

    Karwan, D. L.; Godsey, S.; Rose, L.

    2017-12-01

    Floods can carry >90% of the basin material exported in a given year as well as alter flow pathways and material sources. In turn, sediment and solute fluxes can increase flood damages and negatively impact water quality and integrate physical and chemical weathering of landscapes and channels. Concentration-discharge (C-Q) relationships are used to both describe export patterns as well as compute them. Metrics for describing C-Q patterns and inferring their controls are vulnerable to infrequent sampling that affects how C-Q relationships are interpolated and interpreted. C-Q relationships are typically evaluated from multiple samples, but because hydrological extremes are rare, data are often unavailable for extreme events. Because solute and sediment C-Q relationships likely respond to changes in hydrologic extremes in different ways, there is a pressing need to define their behavior under extreme conditions, including how to properly sample to capture these patterns. In the absence of such knowledge, improving load estimates in extreme floods will likely remain difficult. Here we explore the use of C-Q relationships to determine when an event alters a watershed system such that it enters a new material source/transport regime. We focus on watersheds with sediment and discharge time series include low-frequency and/or extreme events. For example, we compare solute and sediment patterns in White Clay Creek in southeastern Pennsylvania across a range of flows inclusive of multiple hurricanes for which we have ample ancillary hydrochemical data. TSS is consistently mobilized during high flow events, even during extreme floods associated with hurricanes, and sediment fingerprinting indicates different sediment sources, including in-channel remobilization and landscape erosion, are active at different times. In other words, TSS mobilization in C-Q space is not sensitive to the source of material being mobilized. Unlike sediments, weathering solutes in this watershed

  7. In what root-zone N concentration does nitrate start to leach significantly? A reasonable answer from modeling Mediterranean field data and closed root-zone experiments

    Science.gov (United States)

    Kurtzman, D.; Kanner, B.; Levy, Y.; Shapira, R. H.; Bar-Tal, A.

    2017-12-01

    Closed-root-zone experiments (e.g. pots, lyzimeters) reveal in many cases a mineral-nitrogen (N) concentration from which the root-N-uptake efficiency reduces significantly and nitrate leaching below the root-zone increases dramatically. A les-direct way to reveal this threshold concentration in agricultural fields is to calibrate N-transport models of the unsaturated zone to nitrate data of the deep samples (under the root-zone) by fitting the threshold concentration of the nitrate-uptake function. Independent research efforts of these two types in light soils where nitrate problems in underlying aquifers are common reviled: 1) that the threshold exists for most crops (filed, vegetables and orchards); 2) nice agreement on the threshold value between the two very different research methodologies; and 3) the threshold lies within 20-50 mg-N/L. Focusing on being below the threshold is a relatively simple aim in the way to maintain intensive agriculture with limited effects on the nitrate concentration in the underlying water resource. Our experience show that in some crops this threshold coincides with the end-of-rise of the N-yield curve (e.g. corn); in this case, it is relatively easy to convince farmers to fertilize below threshold. In other crops, although significant N is lost to leaching the crop can still use higher N concentration to increase yield (e.g. potato).

  8. Critical zone structure controls concentration-discharge relationships and solute generation in forested tropical montane watersheds

    Science.gov (United States)

    Wymore, Adam S.; Brereton, Richard L.; Ibarra, Daniel E.; Maher, Kate; McDowell, William H.

    2017-07-01

    Concentration-discharge (C-Q) relationships are poorly known for tropical watersheds, even though the tropics contribute a disproportionate amount of solutes to the global ocean. The Luquillo Mountains in Puerto Rico offer an ideal environment to examine C-Q relationships across a heterogeneous tropical landscape. We use 10-30 years of weekly stream chemistry data across 10 watersheds to examine C-Q relationships for weathering products (SiO2(aq), Ca2+, Mg2+, and Na+) and biologically controlled solutes (dissolved organic carbon [DOC], dissolved organic nitrogen [DON], NH4+, NO3-, PO43-, K+, and SO42-). We analyze C-Q relationships using power law equations and a solute production model and use principal component analysis to test hypotheses regarding how the structure of the critical zone controls solute generation. Volcaniclastic watersheds had higher concentrations of weathering solutes and smaller tributaries were approximately threefold more efficient at generating these solutes than larger rivers. Lithology and vegetation explained a significant amount of variation in the theoretical maximum concentrations of weathering solutes (r2 = 0.43-0.48) and in the C-Q relationships of PO43- (r2 = 0.63) and SiO2(aq) (r2 = 0.47). However, the direction and magnitude of these relationships varied. Across watersheds, various forms of N and P displayed variable C-Q relationships, while DOC was consistently enriched with increasing discharge. Results suggest that PO43- may be a useful indicator of watershed function. Relationships between C-Q and landscape characteristics indicate the extent to which the structure and function of the Critical zone controls watershed solute fluxes.

  9. Assessment of dose contribution to population exposure from the radiation sources in the alienated Chernobyl zone

    International Nuclear Information System (INIS)

    Grodzinsky, D.M.; Francevych, L.K.; Koval, H.N.; Yakovlev, E.A.; Bezdrobny, Yu.V.; Proscura, N.I.; Pyantkowsky, V.L.

    1997-01-01

    The main dose load of Ukrainian population is caused by radionuclide-contamination of country territories, located outside the alienated zone, following Chernobyl accident. Besides, much attention could be devoted to the contribution of dose load on population, received from the radioactivity sources that were transferred out from the zone after accident. Present research and analysis of the available documents reflecting the transfer of radioactivity from the alienated zone, provided the estimates of dose load on population, resulting from transfer of the radioactivity sources via following channels: (1) direct surface flow; (2) underground waters; (3) wind-powdered route; (4) transfer with hydrobionts; (5) transfer during irrigation; (6) biogenic route; (7) transport routes and (8) route during wood transportation. Dynamics of radiation transfer through each channel was also studied for the post-accident period. Specific gravity of radioactivity transfer is determined in relation to dose load on Ukrainian population in different regions, in particular, in Dnipro river basin. The perspectives of radioactivity transfer via each of studied channels and its role in dose load on population were also analyzed. On the basis of present results the recommendations on possible arrangements are working out that aimed to reduce the dose contribution in population exposure by radioactivity source transfer from the alienated zone via channels that stipulate the largest dose loads and collective doses

  10. Source zone remediation by ZVI-clay soil-mixing: Reduction of tetrachloroethene mass and mass discharge at a Danish DNAPL site

    DEFF Research Database (Denmark)

    Fjordbøge, Annika Sidelmann; Lange, Ida Vedel; Binning, Philip John

    2012-01-01

    The presence of chlorinated solvent source zones in the subsurface pose a continuous threat to groundwater quality. The remediation of Dense Non-Aqueous Phase Liquid (DNAPL) sites is especially challenging and the development of innovative remediation technologies is needed. Zero-valent iron (ZVI......) technologies have proven effective for remediation of chlorinated compounds. ZVI-Clay soil-mixing is a new remediation technology, which combines abiotic degradation (via ZVI addition) and immobilization (via soil-mixing and clay addition), whereby a great potential for reduction of both contaminant mass....... The concentrations of chlorinated ethenes were monitored via soil sampling at the source zone and groundwater sampling at a control plane with multilevel samplers covering the entire contaminated plume down-gradient (3 m) of the source zone. The results showed a significant mass depletion of PCE (2-3 orders...

  11. CO2 leakage monitoring and analysis to understand the variation of CO2 concentration in vadose zone by natural effects

    Science.gov (United States)

    Joun, Won-Tak; Ha, Seung-Wook; Kim, Hyun Jung; Ju, YeoJin; Lee, Sung-Sun; Lee, Kang-Kun

    2017-04-01

    Controlled ex-situ experiments and continuous CO2 monitoring in the field are significant implications for detecting and monitoring potential leakage from CO2 sequestration reservoir. However, it is difficult to understand the observed parameters because the natural disturbance will fluctuate the signal of detections in given local system. To identify the original source leaking from sequestration reservoir and to distinguish the camouflaged signal of CO2 concentration, the artificial leakage test was conducted in shallow groundwater environment and long-term monitoring have been performed. The monitoring system included several parameters such as pH, temperature, groundwater level, CO2 gas concentration, wind speed and direction, atmospheric pressure, borehole pressure, and rainfall event etc. Especially in this study, focused on understanding a relationship among the CO2 concentration, wind speed, rainfall and pressure difference. The results represent that changes of CO2 concentration in vadose zone could be influenced by physical parameters and this reason is helpful in identifying the camouflaged signal of CO2 concentrations. The 1-D column laboratory experiment also was conducted to understand the sparking-peak as shown in observed data plot. The results showed a similar peak plot and could consider two assumptions why the sparking-peak was shown. First, the trapped CO2 gas was escaped when the water table was changed. Second, the pressure equivalence between CO2 gas and water was broken when the water table was changed. These field data analysis and laboratory experiment need to advance due to comprehensively quantify local long-term dynamics of the artificial CO2 leaking aquifer. Acknowledgement Financial support was provided by the "R&D Project on Environmental Management of Geologic CO2 Storage" from the KEITI (Project Number: 2014001810003)

  12. Spatial and temporal dynamics of organohalide-respiring bacteria in a heterogeneous PCE-DNAPL source zone.

    Science.gov (United States)

    Cápiro, Natalie L; Löffler, Frank E; Pennell, Kurt D

    2015-11-01

    Effective treatment of sites contaminated with dense non-aqueous phase liquids (DNAPLs) requires detailed understanding of the microbial community responses to changes in source zone strength and architecture. Changes in the spatial and temporal distributions of the organohalide-respiring Dehalococcoides mccartyi (Dhc) strains and Geobacter lovleyi strain SZ (GeoSZ) were examined in a heterogeneous tetrachloroethene- (PCE-) DNAPL source zone within a two-dimensional laboratory-scale aquifer flow cell. As part of a combined remedy approach, flushing with 2.3 pore volumes (PVs) of 4% (w/w) solution of the nonionic, biodegradable surfactant Tween® 80 removed 55% of the initial contaminant mass, and resulted in a PCE-DNAPL distribution that contained 51% discrete ganglia and 49% pools (ganglia-to-pool ratio of 1.06). Subsequent bioaugmentation with the PCE-to-ethene-dechlorinating consortium BDI-SZ resulted in cis-1,2-dichloroethene (cis-DCE) formation after 1 PV (ca. 7 days), while vinyl chloride (VC) and ethene were detected 10 PVs after bioaugmentation. Maximum ethene yields (ca. 90 μM) within DNAPL pool and ganglia regions coincided with the detection of the vcrA reductive dehalogenase (RDase) gene that exceeded the Dhc 16S rRNA genes by 2.0±1.3 and 4.0±1.7 fold in the pool and ganglia regions, respectively. Dhc and GeoSZ cell abundance increased by up to 4 orders-of-magnitude after 28 PVs of steady-state operation, with 1 to 2 orders-of-magnitude increases observed in close proximity to residual PCE-DNAPL. These observations suggest the involvement of these dechlorinators the in observed PCE dissolution enhancements of up to 2.3 and 6.0-fold within pool and ganglia regions, respectively. Analysis of the solid and aqueous samples at the conclusion of the experiment revealed that the highest VC (≥155 μM) and ethene (≥65 μM) concentrations were measured in zones where Dhc and GeoSZ were predominately attached to the solids. These findings demonstrate

  13. Evaluating four-dimensional time-lapse electrical resistivity tomography for monitoring DNAPL source zone remediation.

    Science.gov (United States)

    Power, Christopher; Gerhard, Jason I; Karaoulis, Marios; Tsourlos, Panagiotis; Giannopoulos, Antonios

    2014-07-01

    Practical, non-invasive tools do not currently exist for mapping the remediation of dense non-aqueous phase liquids (DNAPLs). Electrical resistivity tomography (ERT) exhibits significant potential but has not yet become a practitioner's tool due to challenges in interpreting the survey results at real sites. This study explores the effectiveness of recently developed four-dimensional (4D, i.e., 3D space plus time) time-lapse surface ERT to monitor DNAPL source zone remediation. A laboratory experiment demonstrated the approach for mapping a changing NAPL distribution over time. A recently developed DNAPL-ERT numerical model was then employed to independently simulate the experiment, providing confidence that the DNAPL-ERT model is a reliable tool for simulating real systems. The numerical model was then used to evaluate the potential for this approach at the field scale. Four DNAPL source zones, exhibiting a range of complexity, were initially simulated, followed by modeled time-lapse ERT monitoring of complete DNAPL remediation by enhanced dissolution. 4D ERT inversion provided estimates of the regions of the source zone experiencing mass reduction with time. Results show that 4D time-lapse ERT has significant potential to map both the outline and the center of mass of the evolving treated portion of the source zone to within a few meters in each direction. In addition, the technique can provide a reasonable, albeit conservative, estimate of the DNAPL volume remediated with time: 25% underestimation in the upper 2m and up to 50% underestimation at late time between 2 and 4m depth. The technique is less reliable for identifying cleanup of DNAPL stringers outside the main DNAPL body. Overall, this study demonstrates that 4D time-lapse ERT has potential for mapping where and how quickly DNAPL mass changes in real time during site remediation. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Cultures of Science and Technology in the Trading Zone: Biodiversity and Open Source Development

    OpenAIRE

    Heaton , Lorna; Dias da Silva , Patrícia

    2016-01-01

    International audience; This paper explores the work of building open source biodiversity information infrastructure. We analyse collaboration between a Canadian team and a Brazilian one. In particular we focus on the use of WingLongitude, a GitHub space, as a trading zone within which the two teams co-developed solutions. We show how the choice to work in a neutral space, belonging to everyone, and the use of display, representation and assemblage practices enabled sharing of some infrastruc...

  15. Comparison of earthquake source parameters and interseismic plate coupling variations in global subduction zones (Invited)

    Science.gov (United States)

    Bilek, S. L.; Moyer, P. A.; Stankova-Pursley, J.

    2010-12-01

    Geodetically determined interseismic coupling variations have been found in subduction zones worldwide. These coupling variations have been linked to heterogeneities in interplate fault frictional conditions. These connections to fault friction imply that observed coupling variations are also important in influencing details in earthquake rupture behavior. Because of the wealth of newly available geodetic models along many subduction zones, it is now possible to examine detailed variations in coupling and compare to seismicity characteristics. Here we use a large catalog of earthquake source time functions and slip models for moderate to large magnitude earthquakes to explore these connections, comparing earthquake source parameters with available models of geodetic coupling along segments of the Japan, Kurile, Kamchatka, Peru, Chile, and Alaska subduction zones. In addition, we use published geodetic results along the Costa Rica margin to compare with source parameters of small magnitude earthquakes recorded with an onshore-offshore network of seismometers. For the moderate to large magnitude earthquakes, preliminary results suggest a complex relationship between earthquake parameters and estimates of strongly and weakly coupled segments of the plate interface. For example, along the Kamchatka subduction zone, these earthquakes occur primarily along the transition between strong and weak coupling, with significant heterogeneity in the pattern of moment scaled duration with respect to the coupling estimates. The longest scaled duration event in this catalog occurred in a region of strong coupling. Earthquakes along the transition between strong and weakly coupled exhibited the most complexity in the source time functions. Use of small magnitude (0.5 earthquake spectra, with higher corner frequencies and higher mean apparent stress for earthquakes that occur in along the Osa Peninsula relative to the Nicoya Peninsula, mimicking the along-strike variations in

  16. Wave-induced release of methane : littoral zones as a source of methane in lakes

    OpenAIRE

    Hofmann, Hilmar; Federwisch, Luisa; Peeters, Frank

    2010-01-01

    This study investigates the role of surface waves and the associated disturbance of littoral sediments for the release and later distribution of dissolved methane in lakes. Surface wave field, wave-induced currents, acoustic backscatter strength, and the concentration and distribution of dissolved methane were measured simultaneously in Lake Constance, Germany. The data indicate that surface waves enhance the release of dissolved methane in the shallow littoral zone via burst-like releases of...

  17. Hydrogeophysical imaging of deposit heterogeneity and groundwater chemistry changes during DNAPL source zone bioremediation.

    Science.gov (United States)

    Chambers, J E; Wilkinson, P B; Wealthall, G P; Loke, M H; Dearden, R; Wilson, R; Allen, D; Ogilvy, R D

    2010-10-21

    Robust characterization and monitoring of dense nonaqueous phase liquid (DNAPL) source zones is essential for designing effective remediation strategies, and for assessing the efficacy of treatment. In this study high-resolution cross-hole electrical resistivity tomography (ERT) was evaluated as a means of monitoring a field-scale in-situ bioremediation experiment, in which emulsified vegetable oil (EVO) electron donor was injected into a trichloroethene source zone. Baseline ERT scans delineated the geometry of the interface between the contaminated alluvial aquifer and the underlying mudstone bedrock, and also the extent of drilling-induced physical heterogeneity. Time-lapse ERT images revealed major preferential flow pathways in the source and plume zones, which were corroborated by multiple lines of evidence, including geochemical monitoring and hydraulic testing using high density multilevel sampler arrays within the geophysical imaging planes. These pathways were shown to control the spatial distribution of the injected EVO, and a bicarbonate buffer introduced into the cell for pH control. Resistivity signatures were observed within the preferential flow pathways that were consistent with elevated chloride levels, providing tentative evidence from ERT of the biodegradation of chlorinated solvents. Copyright © 2010 S. Yamamoto. Published by Elsevier B.V. All rights reserved.

  18. Relict thermokarst carbon source kept stable within gas hydrate stability zone of the South Kara Sea

    Science.gov (United States)

    Portnov, A.; Mienert, J.; Winsborrow, M.; Vadakkepuliyambatta, S.; Semenov, P.

    2017-12-01

    Substantial shallow sources of carbon can exist in the South Kara Sea shelf, extending offshore from the permafrost areas of Yamal Peninsula and the Polar Ural coast. Our study presents new evidence for >250 buried relict thermokarst units. These amalgamated thawing wedges formed in the uppermost permafrost of the past and are still recognizable in today's non-permafrost areas. Part of these potential carbon reservoirs are kept stable within the South Kara Sea gas hydrate stability zone (GHSZ). We utilize an extensive 2D high-resolution seismic dataset, collected in the South Kara Sea in 2005-2006 by Marine Arctic Geological Expedition (MAGE), to map distinctive U-shaped units that are acoustically transparent. These units appear all over the study area in water depths 50-250 m. Created by thermal erosion into Cretaceous-Paleogene bedrock, they are buried under the younger glacio-marine deposits and reach hundreds of meters wide and up to 100 meters thick. They show the characteristics of relict thermokarst, generated during ancient episode(s) of sea level regression of the South Kara Sea. These thermokarst units are generally limited by the Upper Regional Unconformity, which is an erosional horizon created by several glaciation events during the Pleistocene. On land, permafrost is known to sequester large volumes of carbon, half of which is concentrated within thermokarst structures. Based on modern thermokarst analogues we demonstrate with our study that a significant amount of organic carbon can be stored under the Kara Sea. To assess the stability of these shallow carbon reservoirs we carried out GHSZ modeling, constrained by geochemical analyses, temperature measurements and precise bathymetry. This revealed a significant potential for a GHSZ in water depths >225 m. The relict thermokast carbon storage system is stable under today's extremely low bottom water temperatures ( -1.7 °C) that allows for buried GHSZ, located tens of meters below the seabed

  19. Distribution of 210Pb activity concentrations in marine surface sediments within East Coast Peninsula Malaysia Exclusive Economic Zone (EEZ)

    International Nuclear Information System (INIS)

    Ahmad Sanadi Abu Bakar; Zaharudin Ahmad

    2010-01-01

    A sampling expedition into the East Coast Peninsula Malaysia Exclusive Economic Zone (EEZ) was carried in June 2008. Marine surface sediment samples were taken and the activity concentrations of 210 Pb have been determined. Its distribution was plotted and the findings show that the activity concentrations decline from north to south. On the other hand, the activity concentrations are increasing from west to east right to the edge of the EEZ. The highest activity concentrations were found to be near offshore oil platforms. The 210 Pb activity concentrations were found to be in the range of 18.3 - 123.1 Bq/ kg. (author)

  20. Concentrations and size distributions of fine aerosol particles measured at roof level in urban zone

    Science.gov (United States)

    Despiau, S.; Croci, D.

    2007-05-01

    During the experimental Field Experiments to Constrain Models of Atmospheric Pollution and Transport of Emissions (ESCOMPTE) campaign in June-July 2001, concentrations and size distributions of fine particles (14-722 nm) were measured at roof level in downtown Marseille (France). Part of the campaign was dedicated to the study of aerosol behavior in relation to strong photochemical events (which were identified as "IOP" days) and their regional modeling. The analysis of the concentration variations and the evolution of average diurnal size distribution showed that an "IOP day" is not characterized by a specific concentration or its variation, nor by a specific evolution of the average size distribution. The morning traffic rush is detected at roof level by a net increase in particle concentration over the whole size range measured, indicating a production of ultrafine particles by the traffic but also the raising to roof level of particles of the accumulation mode. The increase is observed about 1 hour after the traffic peak at street level, which is characterized by strong increases in NOx and CO concentrations. The corresponding flux of particles at roof level has been estimated around 3 × 104 cm-2 s-1. A specific signature characterized by a strong and rapid burst of concentration (factor 2 to 4 in 15 min) of particles between 25 and 50 nm, independent of the traffic source, has been detected on six occasions during the campaign. These events occur systematically around noon, in cases of strong radiation, low relative humidity, and common wind direction. Despite the high-diameter value of these particles, it is suggested that they could result from a specific "secondary aerosol process" event involving ozone, biogenic, and/or anthropogenic gas precursors like iodine and VOCs.

  1. Effect of the Reburning Zone Stoichiometry on the Nox Concentration at the Three-Stage Combustion of Pulverized Coal

    Directory of Open Access Journals (Sweden)

    Chernetskaya Nelya

    2016-01-01

    Full Text Available Numerical study of heat and mass transfer taking into account the combustion of coal particles in the furnace at the three-stage combustion of pulverized coal was performed. Analysis of the reburning zone stoichiometry on the concentration of nitrogen oxides at the furnace outlet was made. The values of excess air in the primary and reburning combustion zones, providing for the concentration of nitrogen oxides at the furnace outlet is not more than 350 mg/m3 and unburned carbon not more than 1 % when burning coal with a high content of nitrogen were established.

  2. Ammonium and nitrite oxidation at nanomolar oxygen concentrations in oxygen minimum zone waters.

    Science.gov (United States)

    Bristow, Laura A; Dalsgaard, Tage; Tiano, Laura; Mills, Daniel B; Bertagnolli, Anthony D; Wright, Jody J; Hallam, Steven J; Ulloa, Osvaldo; Canfield, Donald E; Revsbech, Niels Peter; Thamdrup, Bo

    2016-09-20

    A major percentage of fixed nitrogen (N) loss in the oceans occurs within nitrite-rich oxygen minimum zones (OMZs) via denitrification and anammox. It remains unclear to what extent ammonium and nitrite oxidation co-occur, either supplying or competing for substrates involved in nitrogen loss in the OMZ core. Assessment of the oxygen (O2) sensitivity of these processes down to the O2 concentrations present in the OMZ core (Chile at manipulated O2 levels between 5 nmol⋅L(-1) and 20 μmol⋅L(-1) Rates of both processes were detectable in the low nanomolar range (5-33 nmol⋅L(-1) O2), but demonstrated a strong dependence on O2 concentrations with apparent half-saturation constants (Kms) of 333 ± 130 nmol⋅L(-1) O2 for ammonium oxidation and 778 ± 168 nmol⋅L(-1) O2 for nitrite oxidation assuming one-component Michaelis-Menten kinetics. Nitrite oxidation rates, however, were better described with a two-component Michaelis-Menten model, indicating a high-affinity component with a Km of just a few nanomolar. As the communities of ammonium and nitrite oxidizers were similar to other OMZs, these kinetics should apply across OMZ systems. The high O2 affinities imply that ammonium and nitrite oxidation can occur within the OMZ core whenever O2 is supplied, for example, by episodic intrusions. These processes therefore compete with anammox and denitrification for ammonium and nitrite, thereby exerting an important control over nitrogen loss.

  3. Earthquake spectra and near-source attenuation in the Cascadia subduction zone

    Science.gov (United States)

    Gomberg, J.; Creager, K.; Sweet, J.; Vidale, J.; Ghosh, A.; Hotovec, A.

    2012-05-01

    Models of seismic source displacement spectra are flat from zero to some corner frequency, fc, regardless of source type. At higher frequencies spectral models decay as f-1 for slow events and as f-2 for fast earthquakes. We show that at least in Cascadia, wave propagation effects likely control spectral decay rates above ˜2 Hz. We use seismograms from multiple small-aperture arrays to estimate the spectral decay rates of near-source spectra of 37 small `events' and find strong correlation between source location and decay rate. The decay rates (1) vary overall by an amount in excess of that inferred to distinguish slow sources from fast earthquakes, (2) are indistinguishable for sources separated by a few tens of km or less, and (3) separate into two populations that correlate with propagation through and outside a low-velocity zone imaged tomographically. We find that some events repeat, as is characteristic of low-frequency earthquakes (LFEs), but have spectra similar to those of non-repeating earthquakes. We also find no correlation between spectral decay rates and rates of ambient tremor activity. These results suggest that earthquakes near the plate boundary, at least in Cascadia, do not distinctly separate into `slow' and `fast' classes, and correctly accounting for propagation effects is necessary to characterize sources.

  4. Starch source in high concentrate rations does not affect rumen pH, histamine and lipopolysaccharide concentrations in dairy cows

    NARCIS (Netherlands)

    Pilachai, R.; Schonewille, J.T.; Thamrongyoswittayakul, C.; Aiumlamai, S.; Wachirapakom, C.; Everts, H.; Hendriks, W.H.

    2012-01-01

    The replacement of ground corn by cassava meal on rumen pH, lipopolysaccharide (LPS) and histamine concentrations under typical Thai feeding conditions (high concentrate diets and rice straw as the sole source of roughage) was investigated. Four rumen-fistulated crossbred Holstein, non-pregnant, dry

  5. [Transfer characteristic and source identification of soil heavy metals from water-level-fluctuating zone along Xiangxi River, three-Gorges Reservoir area].

    Science.gov (United States)

    Xu, Tao; Wang, Fei; Guo, Qiang; Nie, Xiao-Qian; Huang, Ying-Ping; Chen, Jun

    2014-04-01

    Transfer characteristics of heavy metals and their evaluation of potential risk were studied based on determining concentration of heavy metal in soils from water-level-fluctuating zone (altitude:145-175 m) and bank (altitude: 175-185 m) along Xiangxi River, Three Gorges Reservoir area. Factor analysis-multiple linear regression (FA-MLR) was employed for heavy metal source identification and source apportionment. Results demonstrate that, during exposing season, the concentration of soil heavy metals in water-level-fluctuation zone and bank showed the variation, and the concentration of soil heavy metals reduced in shallow soil, but increased in deep soil at water-level-fluctuation zone. However, the concentration of soil heavy metals reduced in both shallow and deep soil at bank during the same period. According to the geoaccumulation index,the pollution extent of heavy metals followed the order: Cd > Pb > Cu > Cr, Cd is the primary pollutant. FA and FA-MLR reveal that in soils from water-level-fluctuation zone, 75.60% of Pb originates from traffic, 62.03% of Cd is from agriculture, 64.71% of Cu and 75.36% of Cr are from natural rock. In soils from bank, 82.26% of Pb originates from traffic, 68.63% of Cd is from agriculture, 65.72% of Cu and 69.33% of Cr are from natural rock. In conclusion, FA-MLR can successfully identify source of heavy metal and compute source apportionment of heavy metals, meanwhile the transfer characteristic is revealed. All these information can be a reference for heavy metal pollution control.

  6. The oxygen minimum zone (OMZ) off Chile as intense source of CO 2 and N 2O

    Science.gov (United States)

    Paulmier, A.; Ruiz-Pino, D.; Garcon, V.

    2008-12-01

    The oxygen minimum zones (OMZs) are recognized as intense sources of N 2O greenhouse gas (GHG) and could also be potential sources of CO 2, the most important GHG for the present climate change. This study evaluates, for one of the most intense and shallow OMZ, the Chilean East South Pacific OMZ, the simultaneous N 2O and CO 2 fluxes at the air-sea interface. Four cruises (2000-2002) and 1 year of monitoring (21°-30°-36°S) off Chile allowed the determination of the CO 2 and N 2O concentrations at the sea surface and the analysis of fluxes variations associated with different OMZ configurations. The Chilean OMZ area can be an intense GHG oceanic local source of both N 2O and CO 2. The mean N 2O fluxes are 5-10 times higher than the maximal previous historical source in an OMZ open area as in the Pacific and Indian Oceans. For CO 2, the mean fluxes are also positive and correspond to very high oceanic sources. Even if different coupling and decoupling between N 2O and CO 2 are observed along the Chilean OMZ, 65% of the situations represent high CO 2 and/or N 2O sources. The high GHG sources are associated with coastal upwelling transport of OMZ waters rich in N 2O and probably also in CO 2, located at a shallow depth. The integrated OMZ role on GHG should be better considered to improve our understanding of the past and future atmospheric CO 2 and N 2O evolutions.

  7. Longitudinal dispersion with time-dependent source concentration ...

    Indian Academy of Sciences (India)

    industries, especially coal-based industries in the industrial states such as Jharkhand and its neigh- bouring states. These industries ..... of the concentration levels of contaminants with time and distance travel- led, may help to rehabilitate the contaminated aquifer and may be useful for groundwater resource management.

  8. Effective Concentration of Elements in Root Zone of Norway Spruce Stand 16 Years After Fertilization Probed with DGT

    Czech Academy of Sciences Publication Activity Database

    Jakl, M.; Jaklová Dytrtová, Jana; Kuneš, I.; Baláš, M.

    2015-01-01

    Roč. 226, č. 10 (2015), 339/1-339/8 ISSN 0049-6979 R&D Projects: GA ČR GP13-21409P Institutional support: RVO:61388963 Keywords : amendment * forest soil * disturbed stand * hazardous elements * DGT * effective concentration * root zone Subject RIV: DK - Soil Contamination ; De-contamination incl. Pesticides Impact factor: 1.551, year: 2015

  9. Effects of root-zone nutrient concentration on cucumber grown in rockwool

    NARCIS (Netherlands)

    Giuffrida, F.; Heuvelink, E.; Stanghellini, C.

    2008-01-01

    We investigated the effects of root-zone heating in early morning to improve the growth of celery and reduce the cost of electricity for root-zone heating during winter in a hilly and mountainous area of Japan. Celery plants were transplanted to a soilless culture system in a sloped greenhouse.

  10. Cascadia Subduction Zone Earthquake Source Spectra from an Array of Arrays

    Science.gov (United States)

    Gomberg, J. S.; Vidale, J. E.

    2011-12-01

    suggests it is more likely that variation in attenuation modulates the spectra. Because the variations in apparent source spectra correlate well with source location, but poorly with receiver location, we infer that near-source attenuation differences likely are much more significant. We conclude that the conventional wisdom may require some revision - that near-source propagation effects may be responsible for some fraction of what has hitherto been attributed to source processes. Moreover, our results further suggest that subduction zone earthquakes do not separate neatly into 'slow' and 'fast' classes, but likely span a continuum.

  11. Exposition by inhalation to the formaldehyde in the air. Source, measures and concentrations; Exposition par inhalation au formaldehyde dans l'air. Source, mesures et concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Del Gratta, F.; Durif, M.; Fagault, Y.; Zdanevitch, I

    2004-12-15

    This document presents the main techniques today available to characterize the formaldehyde concentrations in the air for different contexts: urban and rural areas or around industrial installations but also indoor and occupational area. It provides information to guide laboratories and research departments. A synthesis gives also the main emissions sources of these compounds as reference concentrations measured in different environments. (A.L.B.)

  12. Using artificial sweeteners to identify contamination sources and infiltration zones in a coupled river-aquifer system

    Science.gov (United States)

    Bichler, Andrea; Muellegger, Christian; Hofmann, Thilo

    2014-05-01

    In shallow or unconfined aquifers the infiltration of contaminated river water might be a major threat to groundwater quality. Thus, the identification of possible contamination sources in coupled surface- and groundwater systems is of paramount importance to ensure water quality. Micropollutants like artificial sweeteners are promising markers for domestic waste water in natural water bodies. Compounds, such as artificial sweeteners, might enter the aquatic environment via discharge of waste water treatment plants, leaky sewer systems or septic tanks and are ubiquitously found in waste water receiving waters. The hereby presented field study aims at the (1) identification of contamination sources and (2) delineation of infiltration zones in a connected river-aquifer system. River bank filtrate in the groundwater body was assessed qualitatively and quantitatively using a combined approach of hydrochemical analysis and artificial sweeteners (acesulfame ACE) as waste water markers. The investigated aquifer lies within a mesoscale alpine head water catchment and is used for drinking water production. It is hypothesized that a large proportion of the groundwater flux originates from bank filtrate of a nearby losing stream. Water sampling campaigns in March and July 2012 confirmed the occurrence of artificial sweeteners at the investigated site. The municipal waste water treatment plant was identified as point-source for ACE in the river network. In the aquifer ACE was present in more than 80% of the monitoring wells. In addition, water samples were classified according to their hydrochemical composition, identifying two predominant types of water in the aquifer: (1) groundwater influenced by bank filtrate and (2) groundwater originating from local recharge. In combination with ACE concentrations a third type of water could be discriminated: (3) groundwater influence by bank filtrate but infiltrated prior to the waste water treatment plant. Moreover, the presence of ACE

  13. Trace metal concentrations in mussels in the outfall zones of thermal and nuclear power plants

    International Nuclear Information System (INIS)

    Krishna Kumar, P.T.; Sekimoto, Hiroshi

    2008-01-01

    Many trace elements (TE) like Mn, Fe, Cu, and Zn, occur naturally in marine environments and these TE accomplish decisive functions in humans to maintain good health. Living organisms like Mytilus galloprovincialis are a rich source of TE and are grown extensively near the industrial water outfalls. Some of these TE tend to be pollutants when their elevated levels produce deleterious effects on the ecological system. As chemical analysis for TE toxicity are expensive, organisms like Mytilus galloprovincialis can be used as monitors of environmental contamination. Most studies reported so far are directed towards the effect of a single environmental factor on marine bivalves. However in the areas receiving mixed effluents from various point and non-point sources, the studies on combined effect of two or more stresses would be a more practical approach. In this paper, We investigate the heavy metal concentrations of mercury, cadmium, lead, zinc, cooper, nickel, manganese, and chromium in Mytilus galloprovincialis to provide information on the pollution of water bodies by thermal and nuclear power plants for the choice of sites from where edible mussels can be harvested. We also propose a chemometric approach developed by us using information theory to mitigate trace element toxicity in the edible part of Mytilus galloprovincialis harvested in these sites. (author)

  14. Behaviour of confined sheep fed with different concentrate sources

    Directory of Open Access Journals (Sweden)

    A.H.H. Minervino

    2014-08-01

    Full Text Available In this study we examined the effects of different feed concentrates on sheep behaviour. Our hypothesis was that citric pulp would stimulate rumination and be capable of replacing other concentrates traditionally used for feeding in confinement, to reduce the risk of urolithiasis. Ten adult Santa Inês sheep were distributed in a Latin square with five different diets, one control diet with 80% hay and 20% commercial feed and four diets containing 30% coast-cross hay and 70% of the following concentrates: pelleted citrus pulp, citrus pulp meal, cornmeal or wheat bran. After 21d of adaptation to each one of the five diets, the sheep were visually monitored for 24 h at 3 min intervals to record the time spent ruminating, time spent eating and time spent resting; the animals' positions (standing or lying down were also noted. Daytime was considered to be from 06:00h to 18:00h. The data were evaluated using ANOVA, with Tukey post-hoc test or throughout Two-sample T test for circadian and position assessment. Citrus pulp diets resulted in time spent ruminating similar to the control diet (601, 590 and 669 min, respectively, but greater (P<0.05 than the cornmeal group (421min, which showed that citrus pulp generated effective rumination. The estimated saliva production in the control diet (26L was greater than in the other groups, and was greater in the citrus pulp groups (24L/d than cornmeal (21L/d. Feeding with cornmeal led to shorter time spent eating and time spent ruminating than all other diets. The sheep had higher time spent resting at night when fed concentrates (P<0.05. For all diets, about 90% of the time spent ruminating occurred with the animals lying down. Pelleted citrus pulp, citrus pulp meal and to a lesser degree wheat bran, led to adequate time spent ruminating. The use of citrus pulp can act as a preventive management measure to reduce the incidence of urolithiasis in sheep flocks.

  15. Proceedings of the 2000 contaminated site remediation conference. From source zones to ecosystems. 2 volumes

    International Nuclear Information System (INIS)

    Johnston, C.D.

    2000-01-01

    The conference theme, 'From Source Zones to Ecosystems' , indicate the recognition of the fact that once released into environment, contaminants followed a pathway from the source to the point of impact with an ecosystem or other receptors, consequently care is taken to associate remediation with reducing risk to these receptors. The papers, presented at the conference provide a guide to current practice and future direction of contaminated site remediation in Australia and internationally. Monitored natural attenuation is considered as is an increased body of evidence available to evaluate this approach when managing site contamination for Australian conditions. Remediation strategies for heavy metal contamination appear to be underdeveloped and indeed underrepresented. The phyto remediation is being developed to ameliorate the problem and there is also a focus on the bioavailability of metals and on better defining the risk they pose

  16. Influence of source type and air exchange on variations of indoor radon concentration

    International Nuclear Information System (INIS)

    Arvela, H.; Winqvist, K.

    1986-04-01

    The model relates radon concentration to source strength and its variations, air exchange rate and meteorological factors. Two types of sources have been studied. The pressure difference dependent source is made up of radon transported with soil pore air and driven by pressure difference due to the stack effect. The constant source is made up of radon transported by diffusion from building materials or from soil. The air exchange rate depends exponentially on indoor-outdoor temperature difference and linearly on wind speed. These two inputs have been summed in quadrature. In a house with a constant source radon concentration decreases when the air exchange rate increases due to the increasing temperature difference, whereas the pressure difference dependent source causes an increasing concentration. This is due to the fact that the effect of the source strength increase is stronger than the decreasing effect of air exchange on concentration. The winter-summer concentration ratio depends on the combination of the two types of source. A pure pressure dependent source leads to the winter-summer ratio of 2-3.5 (winter -5 deg C, summer +15 deg C, wind speed 3 m/s). A strong contribution of a constant source is needed to cause a summer concentration higher than the winter concentration. The model is in agreement with the winter-summer concentration ratios measured. This ratio increases with the increasing winter concentration. The measured ratio was near 1.0 for houses with winter concentration of 200 Bq m''3 or less and near 2.0 with concentration of 1000 Bq m''3. In a house with a constant source, the diurnal maximum occurs in the afternoon, while in houses with a pressure difference dependent source the time of maximum is early in the morning

  17. pH control for enhanced reductive bioremediation of chlorinated solvent source zones

    International Nuclear Information System (INIS)

    Robinson, Clare; Barry, D.A.; McCarty, Perry L.; Gerhard, Jason I.; Kouznetsova, Irina

    2009-01-01

    Enhanced reductive dehalogenation is an attractive treatment technology for in situ remediation of chlorinated solvent DNAPL source areas. Reductive dehalogenation is an acid-forming process with hydrochloric acid and also organic acids from fermentation of the electron donors typically building up in the source zone during remediation. This can lead to groundwater acidification thereby inhibiting the activity of dehalogenating microorganisms. Where the soils' natural buffering capacity is likely to be exceeded, the addition of an external source of alkalinity is needed to ensure sustained dehalogenation. To assist in the design of bioremediation systems, an abiotic geochemical model was developed to provide insight into the processes influencing the groundwater acidity as dehalogenation proceeds, and to predict the amount of bicarbonate required to maintain the pH at a suitable level for dehalogenating bacteria (i.e., > 6.5). The model accounts for the amount of chlorinated solvent degraded, site water chemistry, electron donor, alternative terminal electron-accepting processes, gas release and soil mineralogy. While calcite and iron oxides were shown to be the key minerals influencing the soil's buffering capacity, for the extensive dehalogenation likely to occur in a DNAPL source zone, significant bicarbonate addition may be necessary even in soils that are naturally well buffered. Results indicated that the bicarbonate requirement strongly depends on the electron donor used and availability of competing electron acceptors (e.g., sulfate, iron (III)). Based on understanding gained from this model, a simplified model was developed for calculating a preliminary design estimate of the bicarbonate addition required to control the pH for user-specified operating conditions.

  18. pH control for enhanced reductive bioremediation of chlorinated solvent source zones

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, Clare, E-mail: clare.robinson@epfl.ch [Laboratoire de technologie ecologique, Institut d' ingenierie de l' environnement, Station No. 2, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Now at: Department of Civil and Environmental Engineering, University of Western Ontario, London, Canada N6A 5B9 (Canada); Barry, D.A., E-mail: andrew.barry@epfl.ch [Laboratoire de technologie ecologique, Institut d' ingenierie de l' environnement, Station No. 2, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); McCarty, Perry L., E-mail: pmccarty@stanford.edu [Department of Civil and Environmental Engineering, Stanford University, Stanford, CA 94305-4020 (United States); Gerhard, Jason I., E-mail: j.gerhard@ed.ac.uk [Now at: Department of Civil and Environmental Engineering, University of Western Ontario, London, Canada N6A 5B9 (Canada); Institute for Infrastructure and Environment, University of Edinburgh, Edinburgh, EH9 3JL (United Kingdom); Kouznetsova, Irina, E-mail: irina.kouznetsova@ed.ac.uk [Institute for Infrastructure and Environment, University of Edinburgh, Edinburgh, EH9 3JL (United Kingdom)

    2009-08-01

    Enhanced reductive dehalogenation is an attractive treatment technology for in situ remediation of chlorinated solvent DNAPL source areas. Reductive dehalogenation is an acid-forming process with hydrochloric acid and also organic acids from fermentation of the electron donors typically building up in the source zone during remediation. This can lead to groundwater acidification thereby inhibiting the activity of dehalogenating microorganisms. Where the soils' natural buffering capacity is likely to be exceeded, the addition of an external source of alkalinity is needed to ensure sustained dehalogenation. To assist in the design of bioremediation systems, an abiotic geochemical model was developed to provide insight into the processes influencing the groundwater acidity as dehalogenation proceeds, and to predict the amount of bicarbonate required to maintain the pH at a suitable level for dehalogenating bacteria (i.e., > 6.5). The model accounts for the amount of chlorinated solvent degraded, site water chemistry, electron donor, alternative terminal electron-accepting processes, gas release and soil mineralogy. While calcite and iron oxides were shown to be the key minerals influencing the soil's buffering capacity, for the extensive dehalogenation likely to occur in a DNAPL source zone, significant bicarbonate addition may be necessary even in soils that are naturally well buffered. Results indicated that the bicarbonate requirement strongly depends on the electron donor used and availability of competing electron acceptors (e.g., sulfate, iron (III)). Based on understanding gained from this model, a simplified model was developed for calculating a preliminary design estimate of the bicarbonate addition required to control the pH for user-specified operating conditions.

  19. Field demonstration of foam injection to confine a chlorinated solvent source zone.

    Science.gov (United States)

    Portois, Clément; Essouayed, Elyess; Annable, Michael D; Guiserix, Nathalie; Joubert, Antoine; Atteia, Olivier

    2018-05-01

    A novel approach using foam to manage hazardous waste was successfully demonstrated under active site conditions. The purpose of the foam was to divert groundwater flow, that would normally enter the source zone area, to reduce dissolved contaminant release to the aquifer. During the demonstration, foam was pre generated and directly injected surrounding the chlorinated solvent source zone. Despite the constraints related to the industrial activities and non-optimal position of the injection points, the applicability and effectiveness of the approach have been highlighted using multiple metrics. A combination of measurements and modelling allowed definition of the foam extent surrounding each injection point, and this appears to be the critical metric to define the success of the foam injection approach. Information on the transport of chlorinated solvents in groundwater showed a decrease of contaminant flux by a factor of 4.4 downstream of the confined area. The effective permeability reduction was maintained over a period of three months. The successful containment provides evidence for consideration of the use of foam to improve traditional flushing techniques, by increasing the targeting of contaminants by remedial agents. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Variations of soil radon and thoron concentrations in a fault zone and prospective earthquakes in SW Taiwan

    International Nuclear Information System (INIS)

    Yang, T.F.; Walia, V.; Chyi, L.L.; Fu, C.C.; Chen, C.-H.; Liu, T.K.; Song, S.R.; Lee, C.Y.; Lee, M.

    2005-01-01

    An automatic station for soil gas monitoring was set up on an active fault zone of SW Taiwan. After more than one year of continuous measurements, some spike-like anomalous high radon and thoron concentrations could be observed. A similar soil radon spectrum was also obtained from an independent monitoring station, which was only 100m away. These anomalous peaks usually occurred a few days or weeks before the earthquakes (M L >=4.5). This indicates that variations of both soil radon and thoron can serve as useful tools for earthquake surveillance, esp. at fault zones

  1. Flux and Mass Reduction Resulting from ZVIClay Remediation of a PCE DNAPL Source Zone

    DEFF Research Database (Denmark)

    Fjordbøge, Annika Sidelmann; Kjeldsen, Peter; Riis, C.

    2010-01-01

    of bentonite clay. The degradation of PCE in the treated source area and the development in the downstream flux of chlorinated compounds have been monitored in six sampling campaigns. A PCE half-life of 50 days and a reduction of the average concentration of PCE of more than 99% were found during the first...

  2. Concentration peculiarities of radionuclides by freshwater molluscs of Chernobyl NPP exclusion zone

    International Nuclear Information System (INIS)

    Gudkov, D.I.; Kuz'menko, M.I.; Nazarov, A.B.; Derevets, V.V.

    2001-01-01

    The results of radionuclides 90 Sr and 137 Cs content in molluscs tissue of water objects within Chernobyl NPP exclusion zone has been analysed. The age dynamics of radionuclides content in some species of Gastropoda was studied

  3. Euphotic zone bacterioplankton sources major sedimentary bacteriohopanepolyols in the Holocene Black Sea

    Science.gov (United States)

    Blumenberg, Martin; Seifert, Richard; Kasten, Sabine; Bahlmann, Enno; Michaelis, Walter

    2009-02-01

    Bacteriohopanepolyols (BHPs) are lipid constituents of many bacterial groups. Geohopanoids, the diagenetic products, are therefore ubiquitous in organic matter of the geosphere. To examine the potential of BHPs as environmental markers in marine sediments, we investigated a Holocene sediment core from the Black Sea. The concentrations of BHPs mirror the environmental shift from a well-mixed lake to a stratified marine environment by a strong and gradual increase from low values (˜30 μg g -1 TOC) in the oldest sediments to ˜170 μg g -1 TOC in sediments representing the onset of a permanently anoxic water body at about 7500 years before present (BP). This increase in BHP concentrations was most likely caused by a strong increase in bacterioplanktonic paleoproductivity brought about by several ingressions of Mediterranean Sea waters at the end of the lacustrine stage (˜9500 years BP). δ 15N values coevally decreasing with increasing BHP concentrations may indicate a shift from a phosphorus- to a nitrogen-limited setting supporting growth of N 2-fixing, BHP-producing bacteria. In sediments of the last ˜3000 years BHP concentrations have remained relatively stable at about 50 μg g -1 TOC. The distributions of major BHPs did not change significantly during the shift from lacustrine (or oligohaline) to marine conditions. Tetrafunctionalized BHPs prevailed throughout the entire sediment core, with the common bacteriohopanetetrol and 35-aminobacteriohopanetriol and the rare 35-aminobacteriohopenetriol, so far only known from a purple non-sulfur α-proteobacterium, being the main components. Other BHPs specific to cyanobacteria and pelagic methanotrophic bacteria were also found but only in much smaller amounts. Our results demonstrate that BHPs from microorganisms living in deeper biogeochemical zones of marine water columns are underrepresented or even absent in the sediment compared to the BHPs of bacteria present in the euphotic zone. Obviously, the assemblage of

  4. Factors controlling benzo(a)pyrene concentration in aerosols in the urbanized coastal zone. A case study: Gdynia, Poland (Southern Baltic Sea).

    Science.gov (United States)

    Staniszewska, Marta; Graca, Bożena; Bełdowska, Magdalena; Saniewska, Dominika

    2013-06-01

    Annual study on the benzo(a)pyrene (BaP) concentration in aerosols in the coastal zone of the Gulf of Gdansk (southern Baltic) has been performed at Gdynia station. Combustion processes, especially domestic heating of both local and regional origin, were identified as the main sources of benzo(a)pyrene in this area. Concentrations observed during the heating season (mean 2.18 ng m(-3)) were significantly higher than these recorded in the non-heating season (mean 0.05 ng m(-3)). High benzo(a)pyrene concentrations were associated with low temperature and high humidity. Whereas high levels of precipitation usually decreased the BaP concentration in aerosols. The concentration of this factor in the studied area depended also on the wind direction and air masses trajectories. During heating season, continental air masses (coming from S, SE, SW) seemed to increase benzo(a)pyrene concentration, while maritime air masses (from N, NE, NW) caused its decrease. The differences in the BaP concentration resulting from potentially different emission levels of this compound during working and non-working days were not clearly pronounced.

  5. Growth and xanthan production of Xanthomonas campestris depending on the N-source concentration

    Energy Technology Data Exchange (ETDEWEB)

    Prell, A [Academy of Sciences of the Czech Republic, Prague (Czech Republic). Inst. of Microbiology; Lasik, J [Academy of Sciences of the Czech Republic, Prague (Czech Republic). Inst. of Microbiology; Konicek, J [Academy of Sciences of the Czech Republic, Prague (Czech Republic). Inst. of Microbiology; Sobotka, M [Academy of Sciences of the Czech Republic, Prague (Czech Republic). Inst. of Microbiology; Sys, J [Academy of Sciences of the Czech Republic, Prague (Czech Republic). Inst. of Microbiology

    1995-11-01

    Growth of X. campestris and production of xanthan were studied in several batch fermentations with different starting concentrations of N-source. The dependencies of growth, productivity and yields on initial N-source concentration were observed. The maximum yields in the course of cultivations were identified. (orig.)

  6. The Effect of Carbon Source and Fluoride Concentrations in the "Streptococcus Mutans" Biofilm Formation

    Science.gov (United States)

    Paulino, Tony P.; Andrade, Ricardo O.; Bruschi-Thedei, Giuliana C. M.; Thedei, Geraldo, Jr.; Ciancaglini, Pietro

    2004-01-01

    The main objective of this class experiment is to show the influence of carbon source and of different fluoride concentrations on the biofilm formation by the bacterium "Streptococcus mutans." The observation of different biofilm morphology as a function of carbon source and fluoride concentration allows an interesting discussion regarding the…

  7. Quantifying the sources and sinks of nitrite in the oxygen minimum zone of the Eastern Tropical South Pacific

    Science.gov (United States)

    Ji, Qixing; Widner, Brittany; Jayakumar, Amal; Ward, Bess; Mulholland, Margaret

    2017-04-01

    In coastal upwelling regions, high surface productivity leads to high export and intense remineralization consuming oxygen. This, in combination with slow ventilation, creates oxygen minimum zones (OMZ) in eastern boundary regions of the ocean, such as the one off the Peruvian coast in the Eastern Tropical South Pacific. The OMZ is characterized by a layer of high nitrite concentration coinciding with water column anoxia. Sharp oxygen gradients are located above and below the anoxic layer (upper and lower oxyclines). Thus, the OMZ harbors diverse microbial metabolisms, several of which involve the production and consumption of nitrite. The sources of nitrite are ammonium oxidation and nitrate reduction. The sinks of nitrite include anaerobic ammonium oxidation (anammox), canonical denitrification and nitrite oxidation to nitrate. To quantify the sources and sinks of nitrite in the Peruvian OMZ, incubation experiments with 15N-labeled substrates (ammonium, nitrite and nitrate) were conducted on a research cruise in January 2015. The direct measurements of instantaneous nitrite production and consumption rates were compared with ambient nitrite concentrations to evaluate the turnover rate of nitrite in the OMZ. The distribution of nitrite in the water column showed a two-peak structure. A primary nitrite maximum (up to 0.5 μM) was located in the upper oxycline. A secondary nitrite maximum (up to 10 μM) was found in the anoxic layer. A nitrite concentration minimum occurred at the oxic-anoxic interface just below the upper oxycline. For the sources of nitrite, highest rates of ammonium oxidation and nitrate reduction were detected in the upper oxycline, where both nitrite and oxygen concentrations were low. Lower rates of nitrite production were detected within the layer of secondary nitrite maximum. For the sinks of nitrite, the rates of anammox, denitrification and nitrite oxidation were the highest just below the oxic-anoxic interface. Low nitrite consumption

  8. Water Supply Source Evaluation in Unmanaged Aquifer Recharge Zones: The Mezquital Valley (Mexico Case Study

    Directory of Open Access Journals (Sweden)

    Antonio Hernández-Espriú

    2016-12-01

    Full Text Available The Mezquital Valley (MV hosts the largest unmanaged aquifer recharge scheme in the world. The metropolitan area of Mexico City discharges ~60 m3/s of raw wastewater into the valley, a substantial share of which infiltrates into the regional aquifer. In this work, we aim to develop a comprehensive approach, adapted from oil and gas reservoir modeling frameworks, to assess water supply sources located downgradient from unmanaged aquifer recharge zones. The methodology is demonstrated through its application to the Mezquital Valley region. Geological, geoelectrical, petrophysical and hydraulic information is combined into a 3D subsurface model and used to evaluate downgradient supply sources. Although hydrogeochemical variables are yet to be assessed, outcomes suggest that the newly-found groundwater sources may provide a long-term solution for water supply. Piezometric analyses based on 25-year records suggest that the MV is close to steady-state conditions. Thus, unmanaged recharge seems to have been regulating the groundwater balance for the last decades. The transition from unmanaged to managed recharge is expected to provide benefits to the MV inhabitants. It will also be likely to generate new uncertainties in relation to aquifer dynamics and downgradient systems.

  9. Inherent mineralization of 2,6-dichlorobenzamide (BAM) in unsaturated zone and aquifers – Effect of initial concentrations and adaptation

    DEFF Research Database (Denmark)

    Janniche, Gry Sander; Clausen, Liselotte; Albrechtsen, Hans-Jørgen

    2011-01-01

    cores with known dichlobenil application were collected from topsoil to 8.5 m below surface resulting in 57 samples hereof 4 aquifer samples. Mineralization was only substantial (>10%) in the uppermost meter of the unsaturated zone. Microbial adaptation, observed as faster mineralization in pre......, in pre-exposed clay mineralization was stimulated at high concentrations. Furthermore BAM was for the first time mineralized in aerobic aquifer sediments from different BAM-contaminated groundwater locations. BAM mineralization in subsurface and groundwater was demonstrated....

  10. GEMAS - Tin and Tungsten: possible sources of enriched concentrations in soils in European countries

    Science.gov (United States)

    João Batista, Maria; Filipe, Augusto; Reimann, Clemens

    2014-05-01

    Tin and tungsten occur related with magmatic differentiation and can be installed in fissures and veins of magmatic rocks or in the neighbor metasediments. Generally, both elements have low chemical mobility in the superficial environment although effectively mobile in detrital media such as stream sediments and deposited in alluvial soils. The most important tin-tungsten deposits in Europe are in Variscides. From the northern Europe, 985 samples and from southern Europe 1123 samples were collected both in agricultural and grazing lands. Analysis were made of Sn , W, pH, TOC, SiO2 from the upper 20 and 10 cm of agricultural and grazing soils, respectively. The present study is part of the GEMAS project a joint project of European geochemical mapping between the EuroGeoSurvey Geochemical Expert Group and EuroMetaux. The results show that in general, at the European (continental) scale natural processes are dominant. It is clear the distinction between NE Europe and SW European tin and tungsten concentrations in soils. Tin geometric mean concentrations in the northern Europe is 0.57 mg kg-1 in agricultural soils and 0.62 mg kg-1 in grazing land; southern Europe 0.91 mg kg-1 in agricultural soils and 0.95 mg kg-1 in grazing land. Tungsten geometric mean concentrations in northern Europe is 0.067 mg kg-1 in agricultural soils and 0.073 mg kg-1 in grazing land and in southern Europe is 0.085 mg kg-1 in agricultural soils and 0.090 mg kg-1 in grazing land. Limit between north and south is the maximum extent of the last glaciation. Grazing land, undisturbed soils for a period of several years, have higher concentrations of Sn and W than agricultural soils which raises the question that if only natural processes are observed. Parent material seems to be the main source of Sn and W to soil. Sn-W rich Variscan granitic intrusions of Central Iberian Zone, Massif Central, Brittany, Cornwall and Bohemia are reflected in soil concentrations. TOC is higher in northern than in

  11. Content and the forms of heavy metals in bottom sediments in the zone of industrial pollution sources ,

    Directory of Open Access Journals (Sweden)

    Voytyuk Y.Y.

    2014-12-01

    Full Text Available Regularities in the distribution of heavy metals in sediments in the zone of influence of the steel industry in Mariupol are installed. The study results of the forms of occurrence of Zn, Pb, Cu, Cr, Ni are represented. Ecological and geochemical assessment of sediment contamination by heavy metals is performed. The main sources of pollution of bottom sediments are air borne emissions from industrial plants, hydrogenous pollution in industrial sewage entering the water, sewage sludge, ash dumps, slag, ore, sludge, oil spills and salt solutions. Pollution hydrogenous sediments may be significant, contaminated sediments are a source of long-term contamination of water, even after cessation of discharges into rivers untreated wastewater. The environmental condition of bottom sediments in gross content of heavy metals is little information because they do not reflect the transformation and further migration to adjacent environment. The study forms of giving objective information for ecological and geochemical evaluation. The study forms of heavy metals in the sediments carried by successive extracts. Concentrations of heavy metals in the extracts determined by atomic absorption spectrometer analysis CAS-115. It was established that a number of elements typical of exceeding their content in bottom sediments of the background values, due likely to their technogenic origin. Man-made pollution of bottom sediments. Mariupol has disrupted the natural form of the ratio of heavy metals. In the studied sediments form ion exchange increased content of heavy metals, which contributes to their migration in the aquatic environment.

  12. Observations of a narrow zone of high suspended particulate matter (SPM) concentrations along the Dutch coast

    NARCIS (Netherlands)

    van der Hout, C.M.; Gerkema, T.; Nauw, J.J.; Ridderinkhof, H.

    2015-01-01

    The objective of the study described in this paper is to localize the transport path of suspended particulate matter (SPM) in the Dutch coastal zone in the southern North Sea. It is known that a large mass of SPM is transported northward from the Strait of Dover, which is however mostly hidden from

  13. Know Your Enemy - Implementation of Bioremediation within a Suspected DNAPL Source Zone Following High-Resolution Site Characterization at Contractors Road Heavy Equipment Area, Kennedy Space Center, Florida

    Science.gov (United States)

    Chrest, Anne; Daprato, Rebecca; Burcham, Michael; Johnson, Jill

    2018-01-01

    in concentrations observed additional sampling was conducted in 2016. The results identified higher concentrations than originally detected within the previously defined source area and the presence of source zone concentrations upgradient of the previously defined source area (maximum concentration observed 570,000 micro-g/L). The HRSC baseline sampling data allowed for a revision of the bioremediation design prior to implementation. Bioremediation was implemented within the eastern portion of the source area in November and December 2016 and quarterly performance monitoring was completed in March and June 2017. Reductions in CVOC concentrations from baseline were observed at all performance monitoring wells in the treatment area, and by June 2017, an approximate 95% CVOC mass reduction was observed based on monitoring well sampling results. Results/Lessons Learned: The results of this project suggest that, due to the complexity of DNAPL source zones, HRSC during pre-implementation baseline sampling in the TCE source zone was an essential strategy for verifying the treatment area and depth prior to remedy implementation. If the upgradient source zone mass was not identified prior to bioremediation implementation, the mass would have served as a long-term source for the dissolved plume.

  14. Technical Guidance Manual: Contaminant Flux Reduction Barriers for Managing Difficult-to-Treat Source Zones in Unconsolidated Media

    Science.gov (United States)

    2017-06-20

    zone, the site must be:  Comprised of unconsolidated material (gravel, sand, silt, clay )  Have access around the source zone to building the...lower low permeability unit such as a clay to prevent up flow  For accessing the lower cost silica gel grouting technology, the hydraulic...hydraulic conductivity with sodium silicate grout.” (page 4-20).  Viscosities of typical grouts (Powers Figure 22.10)  Typical properties of Sodium

  15. Zone of influence for particle number concentrations at signalised traffic intersections

    Science.gov (United States)

    Goel, Anju; Kumar, Prashant

    2015-12-01

    Estimation of zone of influences (ZoI) at signalised traffic intersections (TI) is important to accurately model particle number concentrations (PNCs) and their exposure to public at emission hotspot locations. However, estimates of ZoI for PNCs at different types of TIs are barely known. We carried out mobile measurements inside the car cabin with windows fully open for size-resolved PNCs in the 5-560 nm range on a 6 km long busy round route that had 10 TIs. These included four-way TIs without built-up area (TI4w-nb), four-way TIs with built-up area (TI4w-wb), three-way TIs without built-up area (TI3w-nb) and three-way TIs with built-up area (TI3w-wb). Mobile measurements were made with a fast response differential mobility spectrometer (DMS50). Driving speed and position of the car were recorded every second using a global positioning system (GPS). Positive matrix factorisation (PMF) modelling was applied on the data to quantify the contribution of PNCs released during deceleration, creep-idling, acceleration and cruising to total PNCs at the TIs. The objectives were to address the following questions: (i) how does ZoI vary at different types of TIs in stop- and go-driving conditions?, (ii) what is the effect of different driving conditions on ZoI of a TI?, (iii) how realistically can the PNC profiles be generalised within a ZoI of a TI?, and (iv) what is the share of emissions during different driving conditions towards the total PNCs at a TI? Average length of ZoI in longitudinal direction and along the road was found to be the highest (148 m; 89 to -59 m from the centre of a TI) at a TI3w-wb, followed by TI4w-nb (129 m; 79 to -42 m), TI3w-nb (86 m; 71 to -15 m) and TI4w-wb (79 m; 46 to -33 m) in stop- and go-driving conditions. During multiple stopping driving conditions when a vehicle stops at a TI more than once in a signal cycle due to oversaturation of vehicles, average length of ZoI increased by 55, 22 and 21% at TI4w-nb, TI3w-nb and TI3w-wb, respectively

  16. Relationships Between Land Use and Stream Nutrient Concentrations in a Highly Urbanized Tropical Region of Brazil: Thresholds and Riparian Zones.

    Science.gov (United States)

    Tromboni, F; Dodds, W K

    2017-07-01

    Nutrient enrichment in streams due to land use is increasing globally, reducing water quality and causing eutrophication of downstream fresh and coastal waters. In temperate developed countries, the intensive use of fertilizers in agriculture is a main driver of increasing nutrient concentrations, but high levels and fast rates of urbanization can be a predominant issue in some areas of the developing world. We investigated land use in the highly urbanized tropical State of Rio de Janeiro, Brazil. We collected total nitrogen, total phosphorus, and inorganic nutrient data from 35 independent watersheds distributed across the State and characterized land use at a riparian and entire watershed scales upstream from each sample station, using ArcGIS. We used regression models to explain land use influences on nutrient concentrations and to assess riparian protection relationships to water quality. We found that urban land use was the primary driver of nutrient concentration increases, independent of the scale of analyses and that urban land use was more concentrated in the riparian buffer of streams than in the entire watersheds. We also found significant thresholds that indicated strong increases in nutrient concentrations with modest increases in urbanization reaching maximum nutrient concentrations between 10 and 46% urban cover. These thresholds influenced calculation of reference nutrient concentrations, and ignoring them led to higher estimates of these concentrations. Lack of sewage treatment in concert with urban development in riparian zones apparently leads to the observation that modest increases in urban land use can cause large increases in nutrient concentrations.

  17. Biostimulation of anaerobic BTEX biodegradation under fermentative methanogenic conditions at source-zone groundwater contaminated with a biodiesel blend (B20).

    Science.gov (United States)

    Ramos, Débora Toledo; da Silva, Márcio Luis Busi; Chiaranda, Helen Simone; Alvarez, Pedro J J; Corseuil, Henry Xavier

    2013-06-01

    Field experiments were conducted to assess the potential for anaerobic biostimulation to enhance BTEX biodegradation under fermentative methanogenic conditions in groundwater impacted by a biodiesel blend (B20, consisting of 20 % v/v biodiesel and 80 % v/v diesel). B20 (100 L) was released at each of two plots through an area of 1 m(2) that was excavated down to the water table, 1.6 m below ground surface. One release was biostimulated with ammonium acetate, which was added weekly through injection wells near the source zone over 15 months. The other release was not biostimulated and served as a baseline control simulating natural attenuation. Ammonium acetate addition stimulated the development of strongly anaerobic conditions, as indicated by near-saturation methane concentrations. BTEX removal began within 8 months in the biostimulated source zone, but not in the natural attenuation control, where BTEX concentrations were still increasing (due to source dissolution) 2 years after the release. Phylogenetic analysis using quantitative PCR indicated an increase in concentration and relative abundance of Archaea (Crenarchaeota and Euryarchaeota), Geobacteraceae (Geobacter and Pelobacter spp.) and sulfate-reducing bacteria (Desulfovibrio, Desulfomicrobium, Desulfuromusa, and Desulfuromonas) in the biostimulated plot relative to the control. Apparently, biostimulation fortuitously enhanced the growth of putative anaerobic BTEX degraders and associated commensal microorganisms that consume acetate and H2, and enhance the thermodynamic feasibility of BTEX fermentation. This is the first field study to suggest that anaerobic-methanogenic biostimulation could enhance source zone bioremediation of groundwater aquifers impacted by biodiesel blends.

  18. Effect of source and environmental factors on Rn-222 air concentration

    International Nuclear Information System (INIS)

    Mamoon, A.

    2005-01-01

    Rn-222(radon) air concentration depends on several factors. Some of the factors are source related and other factors are environmentally related. Because high levels of radon concentrations in air have potential health effects, it is important to study the impact of the various factors affecting radon air concentration. Laboratory scale investigations of the various factors affecting radon air concentration were carried out under controlled conditions that allow variation of the various variables

  19. Using the concentration-volume (C-V) fractal model in the delineation of gold mineralized zones within the Tepeoba porphyry Cu-Mo-Au, Balikesir, NW Turkey

    Science.gov (United States)

    Kumral, Mustafa; Abdelnasser, Amr; Karaman, Muhittin; Budakoglu, Murat

    2016-04-01

    The Tepeoba porphyry Cu-Mo-Au mineralization that located at the Biga peninsula (W Turkey) developed around the Eybek pluton concentrated at its southern contact. This mineralization that hosted in the hornfels rocks of Karakaya Complex is associated with three main alteration zones; potassic, phyllic and propylitic alterations along the fault controlled margins of the Eybek pluton and quartz stockwork veining as well as brecciation zones. As well as two mineralized zones were occurred in the mine area; hypogene and oxidation/supergene zone. The hypogene zone has differentiated alteration types; high potassic and low phyllic alteration, while the oxidation/supergene zone has high phyllic and propylitic alterations. This work deals with the delineation of gold mineralized zone within this porphyry deposit using the concentration-volume (C-V) fractal model. Five zones of gold were calculated using its power-law C-V relationship that revealed that the main phase of gold mineralization stated at 5.3083 ppm Au concentration. In addition, the C-V log-log plot shows that the highly and moderately Au mineralization zone developed in western part of deposit correlated with oxidation zone related to propylitic alteration. On the other hand, its weakly mineralization zone has a widespread in the hypogene zone related to potassic alteration. This refers to the enrichment of gold and depletion of copper at the oxidation/supergene zone is due to the oxidation/supergene alteration processes that enrich the deposits by the meteoric water. Keywords: Concentration-volume (C-V) fractal model; gold mineralized zone; Tepeoba porphyry Cu-Mo-Au; Balikesir; NW Turkey.

  20. Characteristics and source apportionment of organic matter in PM(2.5) from cities in different climatic zones of China

    Science.gov (United States)

    Feng, Jialiang

    For the first time, the dependency of the characteristics of organic matter in PM2.5 on geographical and climatic zones in three metropolitan cities of China was studied. Seasonal samples were collected at suburban and urban sites in Beijing, Shanghai and Guangzhou in 2002 and 2003. To further support the above study, seasonal samples were also collected at Changdao Island, a remote island, in Bohai Sea/Yellow Sea. Concentrations of organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC), and solvent-extractable organic compounds (SEOC) were analyzed. The characteristics of the n-alkanes, polycyclic aromatic hydrocarbons, n-fatty acids, n-alkanols and molecular markers such as triterpanes were determined and used for source identification. Source apportionment was complemented by Chemical Mass Balance (CMB) modeling using the measured organic species as tracers. The impact of wind speed and wind direction on air quality was studied by back trajectory calculations and analysis. In general, traffic emissions were the largest contributors of OC followed by coal burning, kitchen emissions, vegetative detritus and biomass burning. However, in the space-heating season in Northern China, coal burning was the most important contributor of OC in the suburban areas of Beijing and at Changdao. Beijing had the highest concentration of organic aerosol followed by Guangzhou and Shanghai, while seasonal variation was in reverse order. Dispersion conditions determined by local topographies and meteorology were responsible for this trend. Contrary to common understanding, pollutant concentrations at the suburban sites were higher than the urban sites in all three cities. The main reason was the rapid urbanization of the suburban areas in the immediate vicinity of urban centers since China opened up for economic development, in addition, large numbers of manufacturing plants were relocated from the cities to the countryside in an attempt to clean up the urban

  1. Tentative minimum inhibitory concentration and zone diameter breakpoints for moxifloxacin using BSAC criteria.

    Science.gov (United States)

    Andrews, J M; Ashby, J P; Jevons, G M; Wise, R

    1999-12-01

    Tentative MIC and zone diameter breakpoints were determined for moxifloxacin using BSAC criteria. An MIC breakpoint of or = 20 mm for Enterobacteriaceae and staphylococci, 18 mm for the respiratory pathogens (Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis) and 15 mm for enterococci. For Pseudomonas aeruginosa with a 5 microg disc, three bands are suggested for interpretation, that of > or = 25 mm (sensitive), 18-24 mm (intermediate) and < or = 17 mm (resistant).

  2. Application of bimodal distribution to the detection of changes in uranium concentration in drinking water collected by random daytime sampling method from a large water supply zone.

    Science.gov (United States)

    Garboś, Sławomir; Święcicka, Dorota

    2015-11-01

    The random daytime (RDT) sampling method was used for the first time in the assessment of average weekly exposure to uranium through drinking water in a large water supply zone. Data set of uranium concentrations determined in 106 RDT samples collected in three runs from the water supply zone in Wroclaw (Poland), cannot be simply described by normal or log-normal distributions. Therefore, a numerical method designed for the detection and calculation of bimodal distribution was applied. The extracted two distributions containing data from the summer season of 2011 and the winter season of 2012 (nI=72) and from the summer season of 2013 (nII=34) allowed to estimate means of U concentrations in drinking water: 0.947 μg/L and 1.23 μg/L, respectively. As the removal efficiency of uranium during applied treatment process is negligible, the effect of increase in uranium concentration can be explained by higher U concentration in the surface-infiltration water used for the production of drinking water. During the summer season of 2013, heavy rains were observed in Lower Silesia region, causing floods over the territory of the entire region. Fluctuations in uranium concentrations in surface-infiltration water can be attributed to releases of uranium from specific sources - migration from phosphate fertilizers and leaching from mineral deposits. Thus, exposure to uranium through drinking water may increase during extreme rainfall events. The average chronic weekly intakes of uranium through drinking water, estimated on the basis of central values of the extracted normal distributions, accounted for 3.2% and 4.1% of tolerable weekly intake. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Impact of global warming on performance of ground source heat pumps in US climate zones

    International Nuclear Information System (INIS)

    Shen, Pengyuan; Lukes, Jennifer R.

    2015-01-01

    Highlights: • Used morphing method to have downscaled hourly local weather data from GCM. • Selected representative cities in different climate zones in the US for case study on GSHP performance. • Used hourly building simulation tools (eQuest and TRNSYS) to project GSHP performance in future. • Analysis on GSHP performance in 2050 for both residential and office building in the US are conducted. - Abstract: Ground source heat pumps (GSHP) have attracted increasing attention because of their high energy efficiencies. The aim of this paper is to study the performance of (GSHP) in future climate conditions (2040–2069) by using projected future hourly weather data of selected representative cities in the US to estimate future ground temperature change. The projected hourly weather data and estimated ground temperatures are input to an hourly simulation tool (TRNSYS and eQuest for this research), which provides reliable coupling of GSHP system and building performance. The simulation results show that global warming will decrease the energy efficiency of GSHP in US residential buildings because a rise in inlet and outlet water temperature is predicted for GSHP systems during the cooling season and because buildings will become more cooling dominated in the future. For office buildings, although the cooling performance of GSHP will not drop significantly under future climate, the overall energy efficiency for the system will decrease due to the increasing energy consumption of the ground loop pump. In the future, considering the significant ground heat imbalance for GSHP operation, GSHP will become less competitive both economically and technically than it is now in the context of US climate zones

  4. Osmotic concentration in three races of honey bee, Apis mellifera L. under environmental conditions of arid zone.

    Science.gov (United States)

    Ali, Hussain; Alqarni, Abdulaziz S; Owayss, Ayman A; Hassan, Awad M; Smith, Brian H

    2017-07-01

    Hemolymph osmolarity has great effect on honey bee health, especially in arid and semi-arid zones. It regulates water and nutrients in stressed tissues. Osmotic concentration in three races ( Apis mellifera ligustica , A. m. carnica and A. m. jemenitica ) of Apis mellifera was tested in central Saudi Arabia during spring and summer seasons in 2015. Newly emerged bee workers were first marked and later their hemolymph was extracted after intervals of 1, 5, 10, 15, 20 and 25 days. A significant positive correlation between age and osmolarity was found in all three races during spring and summer seasons. The lowest combined osmotic concentration for all three races was found after 1 day interval, while the highest osmotic concentration was recorded after 25 days. Among all races, A. m. ligustica showed significantly high osmotic concentration after 25 days in spring and summer seasons as compared to the other two races. Only A. m. jemenitica showed similar osmotic concentration after 10 and 15 days in both spring and summer seasons compared to other two races. Mean osmotic concentration of all three races was significantly different after 20 and 25 days in spring and summer seasons. Overall mean recorded during summer was significantly higher than the mean of spring season. Combined osmotic concentration in young drones of all races was significantly lower than that of old drones during spring and summer seasons.

  5. In situ quantification of ultra-low O2 concentrations in oxygen minimum zones

    DEFF Research Database (Denmark)

    Larsen, Morten; Lehner, Philipp; Borisov, Sergey M.

    2016-01-01

    based on the palladium(II)-benzoporphyrin luminophore, immobilized in a perfluorinated matrix with high O2 permeability. The trace sensor has a detection limit of ∼5 nmol L−1 with a dynamic range extending up to ∼2 μmol L−1. The sensor demonstrates a response time ..., and fully reversible response to hydrostatic pressure and temperature. The sensor showed excellent stability for continuously measurements during depth profiling in Oxygen Minimum Zones (OMZ). The novel sensor was deployed in situ using a Trace Oxygen Profiler instrument (TOP) equipped with two additional O...

  6. Model Parameter Variability for Enhanced Anaerobic Bioremediation of DNAPL Source Zones

    Science.gov (United States)

    Mao, X.; Gerhard, J. I.; Barry, D. A.

    2005-12-01

    The objective of the Source Area Bioremediation (SABRE) project, an international collaboration of twelve companies, two government agencies and three research institutions, is to evaluate the performance of enhanced anaerobic bioremediation for the treatment of chlorinated ethene source areas containing dense, non-aqueous phase liquids (DNAPL). This 4-year, 5.7 million dollars research effort focuses on a pilot-scale demonstration of enhanced bioremediation at a trichloroethene (TCE) DNAPL field site in the United Kingdom, and includes a significant program of laboratory and modelling studies. Prior to field implementation, a large-scale, multi-laboratory microcosm study was performed to determine the optimal system properties to support dehalogenation of TCE in site soil and groundwater. This statistically-based suite of experiments measured the influence of key variables (electron donor, nutrient addition, bioaugmentation, TCE concentration and sulphate concentration) in promoting the reductive dechlorination of TCE to ethene. As well, a comprehensive biogeochemical numerical model was developed for simulating the anaerobic dehalogenation of chlorinated ethenes. An appropriate (reduced) version of this model was combined with a parameter estimation method based on fitting of the experimental results. Each of over 150 individual microcosm calibrations involved matching predicted and observed time-varying concentrations of all chlorinated compounds. This study focuses on an analysis of this suite of fitted model parameter values. This includes determining the statistical correlation between parameters typically employed in standard Michaelis-Menten type rate descriptions (e.g., maximum dechlorination rates, half-saturation constants) and the key experimental variables. The analysis provides insight into the degree to which aqueous phase TCE and cis-DCE inhibit dechlorination of less-chlorinated compounds. Overall, this work provides a database of the numerical

  7. Space-time quantitative source apportionment of soil heavy metal concentration increments.

    Science.gov (United States)

    Yang, Yong; Christakos, George; Guo, Mingwu; Xiao, Lu; Huang, Wei

    2017-04-01

    Assessing the space-time trends and detecting the sources of heavy metal accumulation in soils have important consequences in the prevention and treatment of soil heavy metal pollution. In this study, we collected soil samples in the eastern part of the Qingshan district, Wuhan city, Hubei Province, China, during the period 2010-2014. The Cd, Cu, Pb and Zn concentrations in soils exhibited a significant accumulation during 2010-2014. The spatiotemporal Kriging technique, based on a quantitative characterization of soil heavy metal concentration variations in terms of non-separable variogram models, was employed to estimate the spatiotemporal soil heavy metal distribution in the study region. Our findings showed that the Cd, Cu, and Zn concentrations have an obvious incremental tendency from the southwestern to the central part of the study region. However, the Pb concentrations exhibited an obvious tendency from the northern part to the central part of the region. Then, spatial overlay analysis was used to obtain absolute and relative concentration increments of adjacent 1- or 5-year periods during 2010-2014. The spatial distribution of soil heavy metal concentration increments showed that the larger increments occurred in the center of the study region. Lastly, the principal component analysis combined with the multiple linear regression method were employed to quantify the source apportionment of the soil heavy metal concentration increments in the region. Our results led to the conclusion that the sources of soil heavy metal concentration increments should be ascribed to industry, agriculture and traffic. In particular, 82.5% of soil heavy metal concentration increment during 2010-2014 was ascribed to industrial/agricultural activities sources. Using STK and SOA to obtain the spatial distribution of heavy metal concentration increments in soils. Using PCA-MLR to quantify the source apportionment of soil heavy metal concentration increments. Copyright © 2017

  8. Reduction of the environmental concentration of air pollutants by proper geometrical orientation of industrial line sources

    International Nuclear Information System (INIS)

    Tadmor, J.

    1980-01-01

    An account is given of an Israeli study of two line sources, one composed of 10 and the other of 20 individual sources. The height of release ranged from 15.7 to 39.6 m, with a uniform rate of release of a gaseous pollutant of 1 Ci/s for each source. Average pollutant concentration was plotted as a function of the rotation angle of the line sources. Reduction of pollutant concentration by a particular rotation of the line sources attained values of up to 50%. At certain rotation angles of the line sources, the environmental concentration was lower even as compared with a single high source. Results also depended on atmospheric conditions. It is suggested that considering the increase in cost of augmenting the height of release as a means of reducing the air pollutant concentration, determination of the optimum geometric orientation of the line sources should be considered as an economical means of improving environmental air quality. (U.K.)

  9. Exposition by inhalation to the formaldehyde in the air. Source, measures and concentrations

    International Nuclear Information System (INIS)

    Del Gratta, F.; Durif, M.; Fagault, Y.; Zdanevitch, I.

    2004-12-01

    This document presents the main techniques today available to characterize the formaldehyde concentrations in the air for different contexts: urban and rural areas or around industrial installations but also indoor and occupational area. It provides information to guide laboratories and research departments. A synthesis gives also the main emissions sources of these compounds as reference concentrations measured in different environments. (A.L.B.)

  10. Can We Manage Nonpoint-Source Pollution Using Nutrient Concentrations during Seasonal Baseflow?

    Directory of Open Access Journals (Sweden)

    James A. McCarty

    2016-05-01

    Full Text Available Nationwide, a substantial amount of resources has been targeted toward improving water quality, particularly focused on nonpoint-source pollution. This study was conducted to evaluate the relationship between nutrient concentrations observed during baseflow and runoff conditions from 56 sites across five watersheds in Arkansas. Baseflow and stormflow concentrations for each site were summarized using geometric mean and then evaluated for directional association. A significant, positive correlation was found for NO–N, total N, soluble reactive P, and total P, indicating that sites with high baseflow concentrations also had elevated runoff concentrations. Those landscape factors that influence nutrient concentrations in streams also likely result in increased runoff, suggesting that high baseflow concentrations may reflect elevated loads from the watershed. The results highlight that it may be possible to collect water-quality data during baseflow to help define where to target nonpoint-source pollution best management practices within a watershed.

  11. Coastal zone color scanner pigment concentrations in the southern ocean and relationships to geophysical surface features

    Science.gov (United States)

    Comiso, J. C.; Mcclain, C. R.; Sullivan, C. W.; Ryan, J. P.; Leonard, C. L.

    1993-01-01

    Climatological data on the distribution of surface pigment fields in the entire southern ocean over a seasonal cycle are examined. The occurrence of intense phytoplankton blooms during austral summer months and during other seasons in different regions is identified and analyzed. The highest pigment concentrations are observed at high latitudes and over regions with water depths usually less than 600 m. Basin-scale pigment distribution shows a slightly asymmetric pattern of enhanced pigment concentrations about Antarctica, with enhanced concentrations extending to lower latitudes in the Atlantic and Indian sectors than in the Pacific sector. A general increase in pigment concentrations is evident from the low latitudes toward the Antarctic circumpolar region. Spatial relationships between pigment and archived geophysical data reveal significant correlation between pigment distributions and both bathymetry and wind stress, while general hemispheric scale patterns of pigment distributions are most coherent with the geostrophic flow of the Antarctic Circumpolar Current.

  12. On the methane paradox: Transport from shallow water zones rather than in situ methanogenesis is the major source of CH4 in the open surface water of lakes

    Science.gov (United States)

    Encinas Fernández, Jorge; Peeters, Frank; Hofmann, Hilmar

    2016-10-01

    Estimates of global methane (CH4) emissions from lakes and the contributions of different pathways are currently under debate. In situ methanogenesis linked to algae growth was recently suggested to be the major source of CH4 fluxes from aquatic systems. However, based on our very large data set on CH4 distributions within lakes, we demonstrate here that methane-enriched water from shallow water zones is the most likely source of the basin-wide mean CH4 concentrations in the surface water of lakes. Consistently, the mean surface CH4 concentrations are significantly correlated with the ratio between the surface area of the shallow water zone and the entire lake, fA,s/t, but not with the total surface area. The categorization of CH4 fluxes according to fA,s/t may therefore improve global estimates of CH4 emissions from lakes. Furthermore, CH4 concentrations increase substantially with water temperature, indicating that seasonally resolved data are required to accurately estimate annual CH4 emissions.

  13. Preliminary Assessment of the Nuclide Migration from the Activation Zone Around the Proposed Spallation Neutron Source Facility

    Energy Technology Data Exchange (ETDEWEB)

    Dole, L.R.

    1998-09-01

    The purpose of this study is to investigate the potential impacts of migrating radionuclides from the activation zone around the proposed Spallation Neutron Source (SNS). Using conservatively high estimates of the potential inventory of radioactive activation products that could form in the proposed compacted-soil shield berm around an SNS facility on the Oak Ridge Reservation (ORR), a conservative, simplified transport model was used to estimate the potential worst-case concentrations of the 12 long-lived isotopes in the groundwater under a site with the hydrologic characteristics of the ORR. Of the 12, only 3 isotopes showed any potential to exceed the U.S. Nuclear Regulatory Commission (NRC) 10 Code of Federal Regulations (CFR) Part 20 Drinking Water Limits (DWLs). These isotopes were 14C, 22Na, and 54Mn. The latter two activation products have very short half-lives of 2.6 years and 0.854 year, respectively. Therefore, these will decay before reaching an off-site receptor, and they cannot pose off-site hazards. However, for this extremely conservative model, which overestimates the mobility of the contaminant, 14C, which has a 5,730-year half-life, was shown to represent a potential concern in the context of this study's conservative assumptions. This study examines alternative modifications to the SNS shield berm and makes recommendations.

  14. Strontium-90 activity concentration in soil samples from the exclusion zone of the Fukushima daiichi nuclear power plant

    Science.gov (United States)

    Sahoo, Sarata Kumar; Kavasi, Norbert; Sorimachi, Atsuyuki; Arae, Hideki; Tokonami, Shinji; Mietelski, Jerzy Wojciech; Łokas, Edyta; Yoshida, Satoshi

    2016-04-01

    The radioactive fission product 90Sr has a long biological half-life (˜18 y) in the human body. Due to its chemical similarity to calcium it accumulates in bones and irradiates the bone marrow, causing its high radio-toxicity. Assessing 90Sr is therefore extremely important in case of a nuclear disaster. In this work 16 soil samples were collected from the exclusion zone (background, stemming from global fallout due to the atmospheric nuclear weapon tests. Correlation analysis between 90Sr and 137Cs activity concentrations provides a potentially powerful tool to discriminate background 90Sr level from its Fukushima contribution.

  15. Seismic source zone characterization for the seismic hazard assessment project PEGASOS by the Expert Group 2 (EG1b)

    International Nuclear Information System (INIS)

    Burkhard, M.; Gruenthal, G.

    2009-01-01

    A comprehensive study of the seismic hazard related to the four NNP sites in NW Switzerland was performed within the project PEGASOS. To account for the epistemic uncertainties involved in the process of the characterization of seismic source zones in the frame of probabilistic seismic hazard assessments, four different expert teams have developed and defended their models in the frame of an intensive elicitation process. Here, the results of one out of four expert groups are presented. The model of this team is based first of all on considerations regarding the large scale tectonics in the context of the Alpine collision, and neotectonic constraints for defining seismic source zones. This leads to a large scale subdivision based on the structural 'architectural' considerations with little input from the present seismicity. Each of the eight large zones was characterized by the style of present-day faulting, fault orientation, and hypo central depth distribution. A further subdivision of the larger zones is performed based on information provided by the seismicity patterns. 58 small source zones have been defined in this way, each of them characterized by the available tectonic constrains, as well as the pros and cons of different existing geologic views connected to them. Of special concern in this respect were the discussion regarding thin skinned vs. thick skinned tectonics, the tectonic origin of the 1356 Basel earthquake, the role of the Permo-Carboniferous graben structures, and finally the seismogenic orientation of faults with respect to the recent crustal stress field. The uncertainties connected to the delimitations of the small source zones have been handled in form of their regrouping, formalized by the logic tree technique. The maximum magnitudes were estimated as discretized probability distribution functions. After de-clustering the used ECOS earthquake catalogue and an analysis of data completeness as a function of time the parameters of the

  16. Tree Coring as a Complement to Soil Gas Screening to Locate PCE and TCE Source Zones and Hot Spots

    DEFF Research Database (Denmark)

    Nielsen, Mette Algreen; Trapp, Stefan; Rehne Jensen, Pernille

    2015-01-01

    ) or trichloroethylene (TCE) to evaluate their ability to locate source zones and contaminant hot spots. One test site represented a relatively homogeneous sandy soil and aquifer, and the second a more heterogeneous geology with both sandy and less permeable clay till layers overlying a chalk aquifer. Tree cores from...

  17. Identifying urban sources as cause of elevated grass pollen concentrations using GIS and remote sensing

    DEFF Research Database (Denmark)

    Skjøth, Carsten Ambelas; Ørby, Pia Viuf; Becker, Thomas

    2013-01-01

    available remote sensing data combined with management information for local grass areas. The inventory has identified a number of grass pollen source areas present within the city domain. The comparison of the measured pollen concentrations with the inventory shows that the atmospheric concentrations......We examine here the hypothesis that during flowering, the grass pollen concentrations at a specific site reflect the distribution of grass pollen sources within a few kilometres of this site. We perform this analysis on data from a measurement campaign in the city of Aarhus (Denmark) using three...

  18. Comparisons of Source Characteristics between Recent Inland Crustal Earthquake Sequences inside and outside of Niigata-Kobe Tectonic Zone, Japan

    Science.gov (United States)

    Somei, K.; Asano, K.; Iwata, T.; Miyakoshi, K.

    2012-12-01

    After the 1995 Kobe earthquake, many M7-class inland earthquakes occurred in Japan. Some of those events (e.g., the 2004 Chuetsu earthquake) occurred in a tectonic zone which is characterized as a high strain rate zone by the GPS observation (Sagiya et al., 2000) or dense distribution of active faults. That belt-like zone along the coast in Japan Sea side of Tohoku and Chubu districts, and north of Kinki district, is called as the Niigata-Kobe tectonic zone (NKTZ, Sagiya et al, 2000). We investigate seismic scaling relationship for recent inland crustal earthquake sequences in Japan and compare source characteristics between events occurring inside and outside of NKTZ. We used S-wave coda part for estimating source spectra. Source spectral ratio is obtained by S-wave coda spectral ratio between the records of large and small events occurring close to each other from nation-wide strong motion network (K-NET and KiK-net) and broad-band seismic network (F-net) to remove propagation-path and site effects. We carefully examined the commonality of the decay of coda envelopes between event-pair records and modeled the observed spectral ratio by the source spectral ratio function with assuming omega-square source model for large and small events. We estimated the corner frequencies and seismic moment (ratio) from those modeled spectral ratio function. We determined Brune's stress drops of 356 events (Mw: 3.1-6.9) in ten earthquake sequences occurring in NKTZ and six sequences occurring outside of NKTZ. Most of source spectra obey omega-square source spectra. There is no obvious systematic difference between stress drops of events in NKTZ zone and others. We may conclude that the systematic tendency of seismic source scaling of the events occurred inside and outside of NKTZ does not exist and the average source scaling relationship can be effective for inland crustal earthquakes. Acknowledgements: Waveform data were provided from K-NET, KiK-net and F-net operated by

  19. Concentration of strain in a marginal rift zone of the Japan backarc during post-rift compression

    Science.gov (United States)

    Sato, H.; Ishiyama, T.; Kato, N.; Abe, S.; Shiraishi, K.; Inaba, M.; Kurashimo, E.; Iwasaki, T.; Van Horne, A.; No, T.; Sato, T.; Kodaira, S.; Matsubara, M.; Takeda, T.; Abe, S.; Kodaira, C.

    2015-12-01

    Late Cenozoic deformation zones in Japan may be divided into two types: (1) arc-arc collision zones like those of Izu and the Hokkaido axial zone, and (2) reactivated back-arc marginal rift (BMR) systems. A BMR develops during a secondary rifting event that follows the opening of a back-arc basin. It forms close to the volcanic front and distant from the spreading center of the basin. In Japan, a BMR system developed along the Sea of Japan coast following the opening of the Japan Sea. The BMR appears to be the weakest, most deformable part of the arc back-arc system. When active rifting in the marginal basins ended, thermal subsidence, and then mechanical subsidence related to the onset of a compressional stress regime, allowed deposition of up to 5 km of post-rift, deep-marine to fluvial sedimentation. Continued compression produced fault-related folds in the post-rift sediments, in thin-skin style deformation. Shortening reached a maximum in the BMR system compared to other parts of the back-arc, suggesting that it is the weakest part of the entire system. We examined the structure of the BMR system using active source seismic investigation and earthquake tomography. The velocity structure beneath the marginal rift basin shows higher P-wave velocity in the upper mantle/lower crust which suggests significant mafic intrusion and thinning of the upper continental crust. The syn-rift mafic intrusive forms a convex shape, and the boundary between the pre-rift crust and the mafic intrusive dips outward. In the post-rift compressional stress regime, the boundary of the mafic body reactivated as a reverse fault, forming a large-scale wedge thrust and causing further subsidence of the rift basin. The driver of the intense shortening event along the Sea of Japan coast in SW Japan was the arrival of a buoyant young (15 Ma) Shikoku basin at the Nankai Trough. Subduction stalled and the backarc was compressed. As the buoyant basin cooled, subduction resumed, and the rate of

  20. Capillary zone electrophoresis-tandem mass spectrometry detects low concentration host cell impurities in monoclonal antibodies

    Science.gov (United States)

    Zhu, Guijie; Sun, Liangliang; Heidbrink-Thompson, Jennifer; Kuntumalla, Srilatha; Lin, Hung-yu; Larkin, Christopher J.; McGivney, James B.; Dovichi, Norman J.

    2016-01-01

    We have evaluated capillary zone electrophoresis-electrospray ionization-tandem mass spectrometry (CZE-ESI-MS/MS) for detection of trace amounts of host cell protein impurities in recombinant therapeutics. Compared to previously published procedures, we have optimized the buffer pH used in the formation of a pH junction to increase injection volume. We also prepared a five-point calibration curve by spiking twelve standard proteins into a solution of a human monoclonal antibody. A custom CZE-MS/MS system was used to analyze the tryptic digest of this mixture without depletion of the antibody. CZE generated a ~70 min separation window (~90 min total analysis duration) and ~300 peak capacity. We also analyzed the sample using ultra-performance liquid chromatography (UPLC)-MS/MS. CZE-MS/MS generated ~five times higher base peak intensity and more peptide identifications for low-level spiked proteins. Both methods detected all proteins spiked at the ~100 ppm level with respect to the antibody. PMID:26530276

  1. A comment on the generalization of the theoretical basis of photovoltaic concentrators for extended light sources

    Science.gov (United States)

    Luque, A.

    1982-04-01

    Maximum optical concentration is achieved by a solar cell collector when it is illuminated isotropically, with the concentrator oriented in such a way that solar source area, A(s)-prime, equals the area of highest energy collection, A(s). It is shown that the A(s)-prime/A(s) orientation factor permits the application of the theory proposed by Luque (1981) to concentrators which are not optimally oriented, such as asymmetric concentrators, with emphasis on errors that could arise from not using the orientation factor.

  2. Atmospheric deposition of trace elements around point sources and human health risk assessment. I: Impact zones around a lead source

    DEFF Research Database (Denmark)

    Moseholm, L.; Larsen, Erik Huusfeldt; Andersen, B.

    1992-01-01

    The deposition of lead was monitored over 8 years in the area around a car battery factory north of Copenhagen, Denmark. The area also has heavy traffic. Deposition was measured by in-situ grown vegetables, transplant grass culture biomonitors, bulk deposition and soil samples. Three impact zones...... were identified by a multivariate statistical analysis. Within each zone, the total dietary intake of lead was estimated for adults and children as a percentage of the provisional tolerably weekly intake (PTWI), and as a result recommendation on restrictions in use of locally grown fruit and vegetables...

  3. Measurements of colloid concentrations in the fracture zone, Aespoe Hard Rock Laboratory, Sweden

    International Nuclear Information System (INIS)

    Ledin, A.; Dueker, A.; Karlsson, Stefan; Allard, B.

    1995-06-01

    The applicability of light scattering in combination with photon correlation spectroscopy (PCS) for determination of concentration and size distribution of colloidal matter in a deep groundwater was tested in situ and on-line. Well-defined reference colloids of Fe 2 O 3 , Al(OH) 3 , SiO 2 , kaolinite, illite and a high molecular humic acid in aqueous media were used as model substances for calibration of the PCS instrument. The intensity of scattered light was found to be dependent on the composition of the colloids. The colloid concentration in the rather saline groundwater was below the detection limit for the PCS equipment used, which corresponds to a colloid concentration not higher than 0.5 mg/l and probably below 0.1 mg/l according to the measurements on-line and in situ at Aespoe and in comparison to the calibrations performed with reference colloids. The results clearly demonstrated that the stability, concentration and composition of a colloid-size suspended phase in the anoxic groundwater with high content of Fe(II), like the one in Aespoe, is extremely sensitive to exposure to atmospheric conditions during sample handling and preparation. Diffusion of air into the closed measuring cuvette was enough to alter the colloid content significantly within 6 hours. A particle fraction with the size distribution in the range 170-700 nm was formed within 45 min when air was allowed to diffuse into the aqueous phase from the air filled upper part of the cuvette. The corresponding time to generate a significant colloid precipitate was less than 1 min when a stream of air was bubbled through the water samples. The precipitated colloid phase consisted of a mixture of ferric (hydr)oxide and calcium carbonate in all three cases. 53 refs, 8 figs, 2 tabs

  4. Localization of epileptogenic zones in Lennox–Gastaut syndrome using frequency domain source imaging of intracranial electroencephalography: a preliminary investigation

    International Nuclear Information System (INIS)

    Cho, Jae-Hyun; Jung, Young-Jin; Kim, Jeong-Youn; Im, Chang-Hwan; Kang, Hoon-Chul; Kim, Heung Dong; Yoon, Dae Sung; Lee, Yong-Ho

    2013-01-01

    Although intracranial electroencephalography (iEEG) has been widely used to localize epileptogenic zones in epilepsy, visual inspection of iEEG recordings does not always result in a favorable surgical outcome, especially in secondary generalized epilepsy such as Lennox–Gastaut syndrome (LGS). Various computational iEEG analysis methods have recently been introduced to confirm the visual inspection results. Of these methods, high gamma oscillation in iEEG has attracted interest because a series of studies have reported a close relationship between epileptogenic zones and cortical areas with high gamma oscillation. Meanwhile, frequency domain source imaging of EEG and MEG oscillations has proven to be a useful auxiliary tool for identifying rough locations of epileptogenic zones. To the best of our knowledge, however, frequency domain source imaging of high gamma iEEG oscillations has not been studied. In this study, we investigated whether the iEEG-based frequency domain source imaging of high gamma oscillation (60–100 Hz) would be a useful supplementary tool for identifying epileptogenic zones in patients with secondary generalized epilepsy. The method was applied to three successfully operated on LGS patients, whose iEEG contained some ictal events with distinct high gamma oscillations before seizure onset. The resultant cortical source distributions were compared with surgical resection areas and with high gamma spectral power distributions on the intracranial sensor plane. While the results of the sensor-level analyses contained many spurious activities, the results of frequency domain source imaging coincided better with the surgical resection areas, suggesting that the frequency domain source imaging of iEEG high gamma oscillations might help enhance the accuracy of pre-surgical evaluations of patients with secondary generalized epilepsy. (paper)

  5. Carbon monoxide concentration in donated blood: relation to cigarette smoking and other sources.

    Science.gov (United States)

    Aberg, Anna-Maja; Sojka, Birgitta Nilsson; Winsö, Ola; Abrahamsson, Pernilla; Johansson, Göran; Larsson, Jan Erik

    2009-02-01

    Carbon monoxide (CO) is normally present in the human body due to endogenous production of CO. CO can also be inhaled by exposure to external sources such as cigarette smoke, car exhaust, and fire. The purpose of this study was to investigate CO concentrations in blood from 410 blood donors at the blood center in Umeå, Sweden. To further evaluate the effects of cigarette smoking on CO concentrations, the elimination time for CO was examined in six volunteer smokers after a smoked cigarette. Blood samples from whole blood donors were obtained during the blood center's routine operation. In connection with blood donations, demographic and behavioral data were collected from the donors. The CO concentration was determined using gas chromatography. The majority of blood donors had approximately the same CO concentration (mean, 84.5 micromol/L). In 6 percent of the samples, the concentrations were higher than 130 micromol per L. The highest CO concentration was 561 micromol per L. The main source for these high CO concentrations appeared to be cigarette smoking. In the volunteer smokers, the elimination time after a smoked cigarette varied significantly, with elimination half-lives from 4.7 to 8.4 hours. These results show that blood bank red blood cell bags may have CO concentrations above the physiologic level. The time interval between cigarette smoking and blood donation seems to be a particularly important factor for elevated CO concentrations.

  6. Normal and anomalous diffusion in fluctuations of dust concentration nearby emission source

    Science.gov (United States)

    Szczurek, Andrzej; Maciejewska, Monika; Wyłomańska, Agnieszka; Sikora, Grzegorz; Balcerek, Michał; Teuerle, Marek

    2018-02-01

    Particulate matter (PM) is an important component of air. Nowadays, major attention is payed to fine dust. It has considerable environmental impact, including adverse effect on human health. One of important issues regarding PM is the temporal variation of its concentration. The variation contains information about factors influencing this quantity in time. The work focuses on the character of PM concentration dynamics indoors, in the vicinity of emission source. The objective was to recognize between the homogeneous or heterogeneous dynamics. The goal was achieved by detecting normal and anomalous diffusion in fluctuations of PM concentration. For this purpose we used anomalous diffusion exponent, β which was derived from Mean Square Displacement (MSD) analysis. The information about PM concentration dynamics may be used to design sampling strategy, which serves to attain representative information about PM behavior in time. The data analyzed in this work was collected from single-point PM concentration monitoring in the vicinity of seven emission sources in industrial environment. In majority of cases we observed heterogeneous character of PM concentration dynamics. It confirms the complexity of interactions between the emission sources and indoor environment. This result also votes against simplistic approach to PM concentration measurement indoors, namely their occasional character, short measurement periods and long term averaging.

  7. Inherent mineralization of 2,6-dichlorobenzamide (BAM) in unsaturated zone and aquifers - Effect of initial concentrations and adaptation

    Energy Technology Data Exchange (ETDEWEB)

    Janniche, Gry Sander, E-mail: gsja@env.dtu.dk [DTU Environment, Technical University of Denmark, Building 113, DK-2800 Kgs. Lyngby (Denmark); Clausen, Liselotte; Albrechtsen, Hans-Jorgen [DTU Environment, Technical University of Denmark, Building 113, DK-2800 Kgs. Lyngby (Denmark)

    2011-10-15

    The dichlobenil metabolite BAM (2,6-dichlorobenzamide) is frequently detected in aquifers e.g. in Denmark despite the mother compound dichlobenil was banned here since 1997. BAM mineralization was investigated at environmentally relevant concentrations in sediment samples. Undisturbed sediment cores with known dichlobenil application were collected from topsoil to 8.5 m below surface resulting in 57 samples hereof 4 aquifer samples. Mineralization was only substantial (>10%) in the uppermost meter of the unsaturated zone. Microbial adaptation, observed as faster mineralization in pre-exposed than in pristine sediments from the same location, was only evident in sandy sediment where dichlobenil was still present, but not in clayey sediments. Higher initial concentrations (1-5000 {mu}g/kg) did not stimulate mineralization in pristine clayey or sandy sediments, or in pre-exposed sand. However, in pre-exposed clay mineralization was stimulated at high concentrations. Furthermore BAM was for the first time mineralized in aerobic aquifer sediments from different BAM-contaminated groundwater locations. - Highlights: > BAM mineralized in BAM-contaminated aerobic aquifer sediments. > In subsurface, fastest BAM mineralization in pre-exposed sandy sediments. > Increased mineralization (adaptation) only observed in contaminated sandy sediment. > In pristine sediments mineralization ratio increased with decreasing concentrations. - BAM mineralization in subsurface and groundwater was demonstrated.

  8. Risk factors of methane hydrate resource development in the concentrated zones distributed in the eastern Nankai Trough

    Science.gov (United States)

    Yamamoto, K.; Nagakubo, S.

    2009-04-01

    Some environmental and safety concerns on the offshore methane hydrate development have been raised, but the ground of such allegations are sometime not fully reasonable. The risks of methane hydrate resource development to environment and safety should be discussed upon methane hydrate occurrences condition, the production methods, and the designs of production system, under comprehensively scientific manners. In the Phase 1 of the Methane Hydrate Exploitation Program in Japan (FY2001-2008), the Research Consortium for Methane Hydrate Resources in Japan (MH21 Research Consortium) found methane hydrate concentrated zones in the eastern Nankai Trough that are potential prospects for resource development. The concentrated zones are consisted of turbidite-derived sandy sediments and hydrate crystals in pore spaces of sand grains (pore-filling type structure). The MH21 Research Consortium proposed the depressurization method as prime technique due to its efficiency of gas production in such concentrated zones, and has tried to develop conceptual designs of production systems based on the information of existing devices and facilities. Under the condition and circumstances described above, the authors tried to extract and evaluate some risk factors concerning methane hydrate development using depressurization in the area. Leakage of methane gas, that is less harmful substance to ecosystem than heavier hydrocarbons, from production system can be one possible risk. However, in the case of gas production through wellbore, even if catastrophic damages happen in the subsea production system during gas production, the leakages do not continue because the borehole could be filled by seawater and depressurization is stopped immediately. Another possible risk is a leakage of produced gas through seafloor. If methane hydrate production makes high pressure or temperature zones in sediments, the risk should be considered. However, depressurization method makes opposite condition

  9. Dissolved-solids sources, loads, yields, and concentrations in streams of the conterminous United States

    Science.gov (United States)

    Anning, David W.; Flynn, Marilyn E.

    2014-01-01

    Recent studies have shown that excessive dissolved-solids concentrations in water can have adverse effects on the environment and on agricultural, domestic, municipal, and industrial water users. Such effects motivated the U.S. Geological Survey’s National Water Quality Assessment Program to develop a SPAtially-Referenced Regression on Watershed Attributes (SPARROW) model that has improved the understanding of sources, loads, yields, and concentrations of dissolved solids in streams of the conterminous United States.

  10. Probability density function modeling of scalar mixing from concentrated sources in turbulent channel flow

    OpenAIRE

    Bakosi, J.; Franzese, P.; Boybeyi, Z.

    2010-01-01

    Dispersion of a passive scalar from concentrated sources in fully developed turbulent channel flow is studied with the probability density function (PDF) method. The joint PDF of velocity, turbulent frequency and scalar concentration is represented by a large number of Lagrangian particles. A stochastic near-wall PDF model combines the generalized Langevin model of Haworth & Pope with Durbin's method of elliptic relaxation to provide a mathematically exact treatment of convective and viscous ...

  11. Plume persistence caused by back diffusion from thin clay layers in a sand aquifer following TCE source-zone hydraulic isolation.

    Science.gov (United States)

    Parker, Beth L; Chapman, Steven W; Guilbeault, Martin A

    2008-11-14

    This paper concludes that back diffusion from one or a few thin clayey beds in a sand aquifer can cause contaminant persistence above MCLs in a sand aquifer long after the source zone initially causing the plume is isolated or removed. This conclusion is based on an intensive case study of a TCE contaminated site in Florida, with the processes evaluated using numerical modeling. At this site, the TCE DNAPL zone formed decades ago, and was hydraulically isolated by means of an innovative system performing groundwater extraction, treatment and re-injection. Treated water is re-injected in a row of injection wells situated a short distance downgradient of the extraction wells, creating a clean-water displacement front to efficiently flush the downgradient plume. This scheme avoids the creation of stagnation zones typical of most groundwater pump-and-treat systems, thereby minimizing the time for aquifer flushing and therefore downgradient cleanup. The system began operation in August 2002 and although the performance monitoring shows substantial declines in concentrations, detectable levels of TCE and degradation products persist downgradient of the re-injection wells, long after the TCE should have disappeared based on calculations assuming a nearly homogenous sand aquifer. Three hypotheses were assessed for this plume persistence: 1) incomplete source-zone capture, 2) DNAPL occurrence downgradient of the re-injection wells, and 3) back diffusion from one or more thin clay beds in the aquifer. After careful consideration, the first two hypotheses were eliminated, leaving back diffusion as the only plausible hypothesis, supported by detailed measurements of VOC concentrations within and near the clay beds and also by numerical model simulations that closely represent the field site hydrogeologic conditions. The model was also used to simulate a more generalized, hypothetical situation where more thin clayey beds occur in a sand aquifer with an underlying aquitard

  12. Source-receptor relationships between East Asian sulfur dioxide emissions and Northern Hemisphere sulfate concentrations

    Directory of Open Access Journals (Sweden)

    J. Liu

    2008-07-01

    Full Text Available We analyze the effect of varying East Asian (EA sulfur emissions on sulfate concentrations in the Northern Hemisphere, using a global coupled oxidant-aerosol model (MOZART-2. We conduct a base and five sensitivity simulations, in which sulfur emissions from each continent are tagged, to establish the source-receptor (S-R relationship between EA sulfur emissions and sulfate concentrations over source and downwind regions. We find that from west to east across the North Pacific, EA sulfate contributes approximately 80%–20% of sulfate at the surface, but at least 50% at 500 hPa. Surface sulfate concentrations are dominated by local anthropogenic sources. Of the sulfate produced from sources other than local anthropogenic emissions (defined here as "background" sulfate, EA sources account for approximately 30%–50% (over the Western US and 10%–20% (over the Eastern US. The surface concentrations of sulfate from EA sources over the Western US are highest in MAM (up to 0.15 μg/m3, and lowest in DJF (less than 0.06 μg/m3. Reducing EA SO2 emissions will significantly decrease the spatial extent of the EA sulfate influence (represented by the areas where at least 0.1 μg m−3 of sulfate originates from EA over the North Pacific both at the surface and at 500 hPa in all seasons, but the extent of influence is insensitive to emission increases, particularly in DJF and JJA. We find that EA sulfate concentrations over most downwind regions respond nearly linearly to changes in EA SO2 emissions, but sulfate concentrations over the EA source region increase more slowly than SO2 emissions, particularly at the surface and in winter, due to limited availability of oxidants (in particular of H2O2, which oxidizes SO2 to sulfate in the aqueous phase. We find that similar estimates of the S-R relationship for trans-Pacific transport of EA sulfate would be

  13. Sources and concentrations of indoor nitrogen dioxide in Hamburg (west Germany) and Erfurt (east Germany)

    International Nuclear Information System (INIS)

    Cyrys, J.; Woelke, G.; Wichmann, H.E.; Heinrich, J.; Richter, K.

    2000-01-01

    Here we report indoor and outdoor concentrations of NO 2 for Erfurt and Hamburg and assess the contribution of the most important indoor sources (e.g. the presence of gas cooking ranges, smoking) and outdoor sources (traffic exhaust emissions). We examined the relative contribution of the different sources of NO 2 to the total indoor NO 2 levels in Erfurt and Hamburg. NO 2 indoor concentrations in Hamburg were slightly higher than those in Erfurt (i.e. living room: 15 μg m -3 for Erfurt and 17 μg m -3 for Hamburg). A linear regression model including the variables, place of residence, season and outdoor NO 2 levels, location of the home within the city, housing and occupant characteristics accounted for 38% of the NO 2 variance. The most important predictors of indoor NO 2 concentrations were gas in cooking followed by other characteristics, such as ventilation or outdoor NO 2 level. Residences in which gas was used for cooking, or in which occupants smoked, had substantially higher indoor NO 2 concentrations (41 or 18% increase, respectively). An increase in the outdoor NO 2 concentration from the 25th to the 75th-percentile (17 μg m -3 ) was associated with a 33% increase in the living room NO 2 concentration. Multiple regression analysis for both cities separately illustrated that use of gas for cooking was the major indoor source of NO 2 . This variable caused a similar increase in the indoor NO 2 levels in each city (43% in Erfurt and 47% in Hamburg). However, outdoor sources of NO 2 (motor vehicle traffic) contributed more to indoor NO 2 levels in Hamburg than in Erfurt

  14. Gas sampling method for determining pollutant concentrations in the flame zone of two swirl-can combustor modules

    Science.gov (United States)

    Duerr, R. A.

    1975-01-01

    A gas sampling probe and traversing mechanism were developed to obtain detailed measurements of gaseous pollutant concentrations in the primary and mixing regions of combustors in order to better understand how pollutants are formed. The gas sampling probe was actuated by a three-degree-of-freedom traversing mechanism and the samples obtained were analyzed by an on-line gas analysis system. The pollutants in the flame zone of two different swirl-can combustor modules were measured at an inlet-air temperature of 590 K, pressure of 6 atmospheres, and reference velocities of 23 and 30 meters per second at a fuel-air ratio of 0.02. Typical results show large spatial gradients in the gaseous pollutant concentration close to the swirl-can module. Average concentrations of unburned hydrocarbons and carbon monoxide decrease rapidly in the downstream wake regions of each module. By careful and detailed probing, the effect of various module design features on pollutant formation can be assessed. The techniques presently developed seem adequate to obtain the desired information.

  15. Root and leaf abscisic acid concentration impact on gas exchange in tomato (Lycopersicon esculentum Mill plants subjected to partial root-zone drying

    Directory of Open Access Journals (Sweden)

    Maria Valerio

    2017-03-01

    Full Text Available Partial root-zone drying (PRD is a deficit irrigation technique with great potential for water saving. A split-root experiment was conducted on tomato in controlled environment in order to test the response of two long-time storage cultivars to PRD. Ponderosa tomato, a cultivar with yellow fruits, was compared to Giallo tondo di Auletta, a local cultivar from southern Campania (Italy. Plants were subjected to three irrigation treatments: plants receiving an amount of water equivalent to 100% of plant evapotranspiration (V100; plants in which 50% of the amount of water given to V100 was supplied (V50; and plants where one root compartment was irrigated at 50% of water requirements and the other compartment was allowed to dry, and thereafter every side was rewetted alternatively (PRD. The highest levels of leaf abscisic acid (ABA [on average equal to 104 ng g–1 fresh weight FW] were measured in PRD and V50, at 70 days after transplantation. Root ABA concentration in both PRD and V50 reached mean values of 149 ng g–1 FW. There were differences for the irrigation regime in root ABA biosynthesis and accumulation under partial root-zone drying and conventional deficit irrigation (V50. Assimilation rate, stomatal conductance and intercellular CO2 concentration decreased in relation to the irrigation regime by 22, 36 and 12%, respectively, in PRD, V50 and V100 at 50 days after transplantation. Ponderosa variety accumulated 20% more dry matter than Auletta and significant differences were observed in leaf area. In both PRD and V50 of the two varieties, it was possible to save on average 46% of water. Our results indicate that there is still space to optimise the PRD strategy, to further improve the cumulative physiological effects of the root-sourced signaling system.

  16. Earthquake source parameter and focal mechanism estimates for the Western Quebec Seismic Zone in eastern Canada

    Science.gov (United States)

    Rodriguez Padilla, A. M.; Onwuemeka, J.; Liu, Y.; Harrington, R. M.

    2017-12-01

    The Western Quebec Seismic Zone (WQSZ) is a 160-km-wide band of intraplate seismicity extending 500 km from the Adirondack Highlands (United States) to the Laurentian uplands (Canada). Historically, the WQSZ has experienced over fifteen earthquakes above magnitude 5, with the noteworthy MN5.2 Ladysmith event on May 17, 2013. Previous studies have associated seismicity in the area to the reactivation of Early Paleozoic normal faults within a failed Iapetan rift arm, or strength contrasts between mafic intrusions and felsic rocks due to the Mesozoic track of the Great Meteor hotspot. A good understanding of seismicity and its relation to pre-existing structures requires information about event source properties, such as static stress drop and fault plane orientation, which can be constrained via spectral analysis and focal mechanism solutions. Using data recorded by the CNSN and USArray Transportable Array, we first characterize b-value for 709 events between 2012 and 2016 in WQSZ, obtaining a value of 0.75. We then determine corner frequency and seismic moment values by fitting S-wave spectra on transverse components at all stations for 35 events MN 2.7+. We select event pairs with highly similar waveforms, proximal hypocenters, and magnitudes differing by 1-2 units. Our preliminary results using single-station spectra show corner frequencies of 15 to 40 Hz and stress drop values between 7 and 130 MPa, typical of intraplate seismicity. Last, we solve focal mechanism solutions of 35 events with impulsive P-wave arrivals at a minimum of 8 stations using the hybridMT moment tensor inversion algorithm. Our preliminary results suggest predominantly thrust faulting mechanisms, and at times oblique thrust faulting. The P-axis trend of the focal mechanism solutions suggests a principal stress orientation of NE-SW, which is consistent with that derived from focal mechanisms of earthquakes prior to 2013. We plan to fit the event pair spectral ratios to correct for attenuation

  17. St Paul fracture zone intratransform ridge basalts (Equatorial Atlantic): Insight within the mantle source diversity

    Science.gov (United States)

    Hemond, C.; Brunelli, D.; Maia, M.; Prigent, S.; Sichel, S. E.

    2017-12-01

    The St Paul Transform System offsets by 630 km the Equatorial Mid Atlantic Ridge at 1° N. It consists of four Major faults separating three intra transform ridge axes. Volcanic glassy samples were collected inside two intratransform ridge (ITR) segments during the COLMEIA cruise (Maia et al ; 2016) and samples from the third ITR available from a previous cruise ST PAUL (Hékinian et al. 2000). Major, trace elements and Hf, Pb, Sr and Nd isotopes were determined on selected hand picked glass chips. Few glassy samples recovered and analysed from abyssal hill samples open a time window of about 4.5 million years in the chemistry of the northern ITR. Results show that all samples are basaltic in composition but trace elements display contrasting images for the three ITR. The northern ITR samples are all light REE and highly incompatible enriched and are E-MORB; the central ITR samples display rather flat REE pattern with a level on enrichment of the HREE higher than the other two ITR and are T-MORB. Southern ITR samples are more heterogeneous N-MORB to T-MORB with a lower level of HREE. Isotopes reveal that the ITRs sample distinct mantle sources. In various isotope plans, the northern ITR samples plot together with published results from the MAR directly north of the St Paul F.Z. Therefore they exhibit some flavor of the Sierra Leone hotspot interacting with the MAR at 1.7°N. Central and southern ITR samples have very distinct composition from the northern ITR but resemble each other. However, for identical 206Pb/204Pb ratios, central ITR has slightly but significantly higher 207Pb/204Pb and 208Pb/204Pb, also higher 143Nd/144Nd for a given 87Sr/86Sr. Southern ITR is in chemical continuity of the MAR southward. So that central ITR samples display a rather specific composition. Off axis samples corresponding to the activity of the northern ITR up to 4.6 m.y. show that the hotspot contribution was even bigger on the spreading axis than today and might be fading with

  18. Critical Evaluation of State-of-the-Art In Situ Thermal Treatment Technologies for DNAPL Source Zone Treatment

    Science.gov (United States)

    2010-01-01

    valent iron (ZVI) powder in a water/ guar slurry for remediation of chlorinated DNAPL source zones. The ZVI continues the remediation after the thermal...MUST BE FOLLOWED BY PERSONNEL ON SITE 1. Smoking, eating, chewing gum or tobacco, or drinking are forbidden except in clean or designated areas...WORK PRACTICES ER-0314 69 Appendix D THE FOLLOWING PRACTICES MUST BE FOLLOWED BY PERSONNEL ON SITE 12. Smoking, eating, chewing gum or tobacco

  19. LNAPL source zone delineation using soil gases in a heterogeneous silty-sand aquifer

    Science.gov (United States)

    Cohen, Grégory J. V.; Jousse, Florie; Luze, Nicolas; Höhener, Patrick; Atteia, Olivier

    2016-09-01

    Source delineation of hydrocarbon contaminated sites is of high importance for remediation work. However, traditional methods like soil core extraction and analysis or recent Membrane Interface Probe methods are time consuming and costly. Therefore, the development of an in situ method based on soil gas analysis can be interesting. This includes the direct measurement of volatile organic compounds (VOCs) in soil gas taken from gas probes using a PID (Photo Ionization Detector) and the analysis of other soil gases related to VOC degradation distribution (CH4, O2, CO2) or related to presence of Light Non-Aqueous Phase Liquid (LNAPL) as 222Rn. However, in widespread heterogeneous formations, delineation by gas measurements becomes more challenging. The objective of this study is twofold: (i) to analyse the potential of several in situ gas measurement techniques in comparison to soil coring for LNAPL source delineation at a heterogeneous contaminated site where the techniques might be limited by a low diffusion potential linked to the presence of fine sands and silts, and (ii) to analyse the effect of vertical sediment heterogeneities on the performance of these gas measurement methods. Thus, five types of gases were analysed: VOCs, their three related degradation products O2, CO2 and CH4 and 222Rn. Gas measurements were compared to independent LNAPL analysis by coring. This work was conducted at an old industrial site frequently contaminated by a Diesel-Fuel mixture located in a heterogeneous fine-grained aquifer. Results show that in such heterogeneous media migration of reactive gases like VOCs occurs only across small distances and the VOC concentrations sampled with gas probes are mainly related to local conditions rather than the presence of LNAPL below the gas probe. 222Rn is not well correlated with LNAPL because of sediment heterogeneity. Oxygen, CO2, and especially CH4, have larger lengths of diffusion and give the clearest picture for LNAPL presence at this

  20. CONTRIBUTION OF RADON FLOWS AND RADON SOURCES TO THE RADON CONCENTRATION IN A DWELLING

    NARCIS (Netherlands)

    DEMEIJER, RJ; STOOP, P; PUT, LW

    1992-01-01

    In this paper a model is presented for analysis of the radon concentrations in a compartment in terms of contributions from transport by flows of air between compartments and from radon sources in the compartment. Measurements were made to study the effect of increased natural ventilation of the

  1. Contribution from indoor sources to particle number and mass concentrations in residential houses

    Science.gov (United States)

    He, Congrong; Morawska, Lidia; Hitchins, Jane; Gilbert, Dale

    As part of a large study investigating indoor air in residential houses in Brisbane, Australia, the purpose of this work was to quantify emission characteristics of indoor particle sources in 15 houses. Submicrometer particle number and approximation of PM 2.5 concentrations were measured simultaneously for more than 48 h in the kitchen of all the houses by using a condensation particle counter (CPC) and a photometer (DustTrak), respectively. In addition, characterizations of particles resulting from cooking conducted in an identical way in all the houses were measured by using a scanning mobility particle sizer (SMPS), an aerodynamic particle sizer (APS) and a DustTrak. All the events of elevated particle concentrations were linked to indoor activities using house occupants diary entries, and catalogued into 21 different types of indoor activities. This enabled quantification of the effect of indoor sources on indoor particle concentrations as well as quantification of emission rates from the sources. For example, the study found that frying, grilling, stove use, toasting, cooking pizza, cooking, candle vaporizing eucalyptus oil and fan heater use, could elevate the indoor submicrometer particle number concentration levels by more than five times, while PM 2.5 concentrations could be up to 3, 30 and 90 times higher than the background levels during smoking, frying and grilling, respectively.

  2. Evaluation of anionic surfactant concentrations in US effluents and probabilistic determination of their combined ecological risk in mixing zones.

    Science.gov (United States)

    McDonough, Kathleen; Casteel, Kenneth; Itrich, Nina; Menzies, Jennifer; Belanger, Scott; Wehmeyer, Kenneth; Federle, Thomas

    2016-12-01

    Alcohol sulfates (AS), alcohol ethoxysulfates (AES), linear alkyl benzenesulfonates (LAS) and methyl ester sulfonates (MES) are anionic surfactants that are widely used in household detergents and consumer products resulting in over 1 million tons being disposed of down the drain annually in the US. A monitoring campaign was conducted which collected grab effluent samples from 44 wastewater treatment plants (WWTPs) across the US to generate statistical distributions of effluent concentrations for anionic surfactants. The mean concentrations for AS, AES, LAS and MES were 5.03±4.5, 1.95±0.7, 15.3±19, and 0.35±0.13μg/L respectively. Since each of these surfactants consist of multiple homologues that differ in their toxicity, the concentration of each homologue measured in an effluent sample was converted into a toxic unit (TU) by normalizing to the predicted no effect concentration (PNEC) derived from high tier effects data (mesocosm studies). The statistical distributions of the combined TUs in the effluents were used in combination with distributions of dilution factors for WWTP mixing zones to conduct a US-wide probabilistic risk assessment for the aquatic environment for each of the surfactants. The 90th percentile level of TUs for AS, AES, LAS and MES in mixing zones were 1.89×10 -2 , 2.73×10 -3 , 2.72×10 -2 , and 3.65×10 -5 under 7Q10 (lowest river flow occurring over a 7day period every 10years) low flow conditions. Because these surfactants have the same toxicological mode of action, the TUs were summed and the aquatic safety for anionic surfactants as a whole was assessed. At the 90th percentile level under the conservative 7Q10 low flow conditions the forecasted TUs were 4.21×10 -2 which indicates that there is a significant margin of safety for the class of anionic surfactants in US aquatic environments. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Monocular zones in stereoscopic scenes: A useful source of information for human binocular vision?

    Science.gov (United States)

    Harris, Julie M.

    2010-02-01

    When an object is closer to an observer than the background, the small differences between right and left eye views are interpreted by the human brain as depth. This basic ability of the human visual system, called stereopsis, lies at the core of all binocular three-dimensional (3-D) perception and related technological display development. To achieve stereopsis, it is traditionally assumed that corresponding locations in the right and left eye's views must first be matched, then the relative differences between right and left eye locations are used to calculate depth. But this is not the whole story. At every object-background boundary, there are regions of the background that only one eye can see because, in the other eye's view, the foreground object occludes that region of background. Such monocular zones do not have a corresponding match in the other eye's view and can thus cause problems for depth extraction algorithms. In this paper I will discuss evidence, from our knowledge of human visual perception, illustrating that monocular zones do not pose problems for our human visual systems, rather, our visual systems can extract depth from such zones. I review the relevant human perception literature in this area, and show some recent data aimed at quantifying the perception of depth from monocular zones. The paper finishes with a discussion of the potential importance of considering monocular zones, for stereo display technology and depth compression algorithms.

  4. Calculation of the isotope concentrations, source terms and radiation shielding of the SAFARI-1 irradiation products

    International Nuclear Information System (INIS)

    Stoker, C.C.; Ball, G.

    2000-01-01

    The ever increasing expansion of the irradiation product portfolio of the SAFARI-1 reactor leads to the need to routinely calculate the radio-isotope concentrations and source terms for the materials irradiated in the reactor accurately. In addition to this, the required shielding for the transportation and processing of these irradiation products needs to be determined. In this paper the calculational methodology applied is described with special attention given to the spectrum dependence of the one-group cross sections of selected SAFARI-1 irradiation materials and the consequent effect on the determination of the isotope concentrations and source terms. Comparisons of the calculated isotopic concentrations and dose rates with experimental analysis and measurements provide confidence in the calculational methodologies and data used. (author)

  5. Formate as an energy source for microbial metabolism in chemosynthetic zones of hydrothermal ecosystems.

    Science.gov (United States)

    Windman, Todd; Zolotova, Natalya; Schwandner, Florian; Shock, Everett L

    2007-12-01

    Formate, a simple organic acid known to support chemotrophic hyperthermophiles, is found in hot springs of varying temperature and pH. However, it is not yet known how metabolic strategies that use formate could contribute to primary productivity in hydrothermal ecosystems. In an effort to provide a quantitative framework for assessing the role of formate metabolism, concentration data for dissolved formate and many other solutes in samples from Yellowstone hot springs were used, together with data for coexisting gas compositions, to evaluate the overall Gibbs energy for many reactions involving formate oxidation or reduction. The result is the first rigorous thermodynamic assessment of reactions involving formate oxidation to bicarbonate and reduction to methane coupled with various forms of iron, nitrogen, sulfur, hydrogen, and oxygen for hydrothermal ecosystems. We conclude that there are a limited number of reactions that can yield energy through formate reduction, in contrast to numerous formate oxidation reactions that can yield abundant energy for chemosynthetic microorganisms. Because the energy yields are so high, these results challenge the notion that hydrogen is the primary energy source of chemosynthetic microbes in hydrothermal ecosystems.

  6. Sulfide precursor concentration and lead source effect on PbS thin films properties

    International Nuclear Information System (INIS)

    Beddek, L.; Messaoudi, M.; Attaf, N.; Aida, M.S.; Bougdira, J.

    2016-01-01

    Lead sulfide (PbS) thin films were synthesized using chemical bath deposition (CBD). Bath solutions are formed of various concentrations of thiourea, sulfide source, ranged from 0.6 to 1.2 M and two different salts as Pb source (lead acetate and lead nitrate). From the growth mechanism, we inferred that PbS is formed through the ion by ion process when using acetate lead source, while, using nitrate source yields to films growth through the complex-decomposition process. Due to the difference in the involved growth process, lead acetate produces films with larger crystallite size (from 4 to 16 nm), smooth and dense films. However, lead nitrate produces rough films with smaller crystallite size (from 1 to 4 nm). Increasing the thiourea concentration results in crystallinity improvement when using lead acetate and, oppositely, in crystallinity degradation when using lead nitrate. Due to the quantum effect caused by the small crystallite sizes, the films optical gap is varied from 0.5 to 0.9 eV. - Highlights: • PbS thin films were synthesized by chemical bath deposition. • Ion by ion is the growth process when using the acetate lead source. • Deposition process is by complex-decomposition when using nitrate source. • Lead acetate yields to dense films with larger crystallite size. • Lead nitrate produces rough films with smaller crystallite size.

  7. Sulfide precursor concentration and lead source effect on PbS thin films properties

    Energy Technology Data Exchange (ETDEWEB)

    Beddek, L.; Messaoudi, M.; Attaf, N. [Laboratoire Couche Minces et Interfaces, Université frères Mentouri Constantine, 25000, Constantine (Algeria); Aida, M.S., E-mail: aida_salah2@yahoo.fr [Laboratoire Couche Minces et Interfaces, Université frères Mentouri Constantine, 25000, Constantine (Algeria); Bougdira, J. [Université de Lorraine, Institut Jean Lamour UMR 7198, Vandoeuvre 54506 (France)

    2016-05-05

    Lead sulfide (PbS) thin films were synthesized using chemical bath deposition (CBD). Bath solutions are formed of various concentrations of thiourea, sulfide source, ranged from 0.6 to 1.2 M and two different salts as Pb source (lead acetate and lead nitrate). From the growth mechanism, we inferred that PbS is formed through the ion by ion process when using acetate lead source, while, using nitrate source yields to films growth through the complex-decomposition process. Due to the difference in the involved growth process, lead acetate produces films with larger crystallite size (from 4 to 16 nm), smooth and dense films. However, lead nitrate produces rough films with smaller crystallite size (from 1 to 4 nm). Increasing the thiourea concentration results in crystallinity improvement when using lead acetate and, oppositely, in crystallinity degradation when using lead nitrate. Due to the quantum effect caused by the small crystallite sizes, the films optical gap is varied from 0.5 to 0.9 eV. - Highlights: • PbS thin films were synthesized by chemical bath deposition. • Ion by ion is the growth process when using the acetate lead source. • Deposition process is by complex-decomposition when using nitrate source. • Lead acetate yields to dense films with larger crystallite size. • Lead nitrate produces rough films with smaller crystallite size.

  8. Elevated Arsenic and Uranium Concentrations in Unregulated Water Sources on the Navajo Nation, USA.

    Science.gov (United States)

    Hoover, Joseph; Gonzales, Melissa; Shuey, Chris; Barney, Yolanda; Lewis, Johnnye

    2017-01-01

    Regional water pollution and use of unregulated water sources can be an important mixed metals exposure pathway for rural populations located in areas with limited water infrastructure and an extensive mining history. Using censored data analysis and mapping techniques we analyzed the joint geospatial distribution of arsenic and uranium in unregulated water sources throughout the Navajo Nation, where over 500 abandoned uranium mine sites are located in the rural southwestern United States. Results indicated that arsenic and uranium concentrations exceeded national drinking water standards in 15.1 % (arsenic) and 12.8 % (uranium) of tested water sources. Unregulated sources in close proximity (i.e., within 6 km) to abandoned uranium mines yielded significantly higher concentrations of arsenic or uranium than more distant sources. The demonstrated regional trends for potential co-exposure to these chemicals have implications for public policy and future research. Specifically, to generate solutions that reduce human exposure to water pollution from unregulated sources in rural areas, the potential for co-exposure to arsenic and uranium requires expanded documentation and examination. Recommendations for prioritizing policy and research decisions related to the documentation of existing health exposures and risk reduction strategies are also provided.

  9. Indoor concentrations of radon 222 and its daughters: sources, range, and environmental influences

    International Nuclear Information System (INIS)

    Nero, A.V. Jr.

    1985-04-01

    The author here reviews what is presently known about factors affecting indoor concentrations of radon 222 and its daughters. In US single-family homes, radon concentrations are found to average about 1.5 pCi/1, but substantially higher concentrations occur frequently: perhaps a million US homes have concentrations exceeding 8 pCi/1 (from which occupants receive radiation doses comparable to those now experienced by uranium miners). The major contributor to indoor radon is ordinary soil underlying homes, with this radon being transported indoors primarily by the slight depressurization that occurs toward the bottom of a house interior (due to indoor-outdoor temperature differences and winds). Water from underground sources contributes significantly in a minority of cases, primarily residences with private wells, with public water supplies contributing only a few percent of indoor radon, even when drawn from wells. The strong variability in indoor concentrations is associated primarily with variability in the amount of radon entering homes from these various sources, and secondarily with differences in ventilation rates. However, for a given entry rate, the ventilation rate is the key determinant of indoor concentrations. Human doses are also influenced strongly by the chemical behavior of the daughters (i.e., decay products of radon), and considerable progress has been made recently in investigating a major aspect of this behavior, i.e., the manner in which daughters attach to airborne particles, to walls, and - indeed - to the lining of the lung itself, where the key radiation dose occurs

  10. Spatial distribution and source apportionment of water pollution in different administrative zones of Wen-Rui-Tang (WRT) river watershed, China.

    Science.gov (United States)

    Yang, Liping; Mei, Kun; Liu, Xingmei; Wu, Laosheng; Zhang, Minghua; Xu, Jianming; Wang, Fan

    2013-08-01

    Water quality degradation in river systems has caused great concerns all over the world. Identifying the spatial distribution and sources of water pollutants is the very first step for efficient water quality management. A set of water samples collected bimonthly at 12 monitoring sites in 2009 and 2010 were analyzed to determine the spatial distribution of critical parameters and to apportion the sources of pollutants in Wen-Rui-Tang (WRT) river watershed, near the East China Sea. The 12 monitoring sites were divided into three administrative zones of urban, suburban, and rural zones considering differences in land use and population density. Multivariate statistical methods [one-way analysis of variance, principal component analysis (PCA), and absolute principal component score-multiple linear regression (APCS-MLR) methods] were used to investigate the spatial distribution of water quality and to apportion the pollution sources. Results showed that most water quality parameters had no significant difference between the urban and suburban zones, whereas these two zones showed worse water quality than the rural zone. Based on PCA and APCS-MLR analysis, urban domestic sewage and commercial/service pollution, suburban domestic sewage along with fluorine point source pollution, and agricultural nonpoint source pollution with rural domestic sewage pollution were identified to the main pollution sources in urban, suburban, and rural zones, respectively. Understanding the water pollution characteristics of different administrative zones could put insights into effective water management policy-making especially in the area across various administrative zones.

  11. Predicting DNAPL Source Zone and Plume Response Using Site-Measured Characteristics

    Science.gov (United States)

    2017-05-19

    Losses must be considered such as complete degradation, changes in hydro -stratigraphy, and remediation. c. Use of Extraction Wells Changes in...coal tar is polyparameter linear free energy relationships which uses a mechanistic description of the intermolecular interactions. Final Report ER...used to identify zones of contamination. There were three electric conductivity logging tools tested: the flame ionization detector (FID), the

  12. Diffusive transport and evaporation to the atmosphere from a NAPL source in the vadose zone

    DEFF Research Database (Denmark)

    Holtegaard, L.E.; Bjerre, T.; Christophersen, Mette

    2002-01-01

    To evaluate the risks concerned with the presence of volatile organic compounds in the unsaturated zone it is important to know how the compounds are transported in the soil. In this project the effective diffusion coefficient of 3-methylpentane, hexane, methyl-cyclopentane, iso-octane and methyl...

  13. A model for the development of marginal water sources in arid zones: The case of the Negev Desert, Israel

    Science.gov (United States)

    Brimberg, Jack; Oron, Gideon; Mehrez, Abraham

    1993-09-01

    A management model is presented for the optimal development of marginal water sources in arid zones in conjunction with minimizing the dependence on high-quality water. These marginal sources, which may include among others saline groundwater, treated wastewater, and runoff water, are required to augment a limited supply from regional sources. The objective is to minimize operational and capital costs while simultaneously allocating a conventional regional supply in a best way among a set of local sites. A novel aspect is the consideration of water quality as an additional constraint in the decision model. In this way an optimal investment strategy for marginal water source development and use is obtained while satisfying quality requirements at the individual sites. The model formulated takes the form of a mixed binary integer linear problem. The main purpose of the presented model is to delineate a methodology for marginal water considerations and development in arid zones. Water qualities, supply and demand for diverse uses, and related costs are of primary importance. Several simplifying assumptions are made, such as aggregation on an annual basis, in order to cope with the essential features of the problem at a reasonable level of complexity. These assumptions may be relaxed at a later, more detailed stage of analysis. A case study of the Negev Desert in southern Israel is shown. An important conclusion is that saline groundwater production at local demand sites should be increased dramatically. The usefulness of sensitivity analysis in the decision process is also demonstrated.

  14. Thermal convection at low Rayleigh number from concentrated sources in porous media

    International Nuclear Information System (INIS)

    Hickox, C.E.

    1980-01-01

    A simple mathematical theory is proposed for the analysis of natural convective motion, at low Rayleigh number, from a concentrated source of heat in a fluid-saturated porous medium. The theory consists of retaining only the leading terms of series expansions of the dependent variables in terms of the Rayleigh number, is thus linear, and is valid only in the limit of small Rayleigh number. Based on fundamental results for a variety of isolated sources, superposition is used to provide solutions for situations of practical interest. Special emphasis is given to the analysis of sub-seabed disposal of nuclear waste. 8 figures

  15. Global source attribution of sulfate concentration and direct and indirect radiative forcing

    Science.gov (United States)

    Yang, Yang; Wang, Hailong; Smith, Steven J.; Easter, Richard; Ma, Po-Lun; Qian, Yun; Yu, Hongbin; Li, Can; Rasch, Philip J.

    2017-07-01

    The global source-receptor relationships of sulfate concentrations, and direct and indirect radiative forcing (DRF and IRF) from 16 regions/sectors for years 2010-2014 are examined in this study through utilizing a sulfur source-tagging capability implemented in the Community Earth System Model (CESM) with winds nudged to reanalysis data. Sulfate concentrations are mostly contributed by local emissions in regions with high emissions, while over regions with relatively low SO2 emissions, the near-surface sulfate concentrations are primarily attributed to non-local sources from long-range transport. Regional source efficiencies of sulfate concentrations are higher over regions with dry atmospheric conditions and less export, suggesting that lifetime of aerosols, together with regional export, is important in determining regional air quality. The simulated global total sulfate DRF is -0.42 W m-2, with -0.31 W m-2 contributed by anthropogenic sulfate and -0.11 W m-2 contributed by natural sulfate, relative to a state with no sulfur emissions. In the Southern Hemisphere tropics, dimethyl sulfide (DMS) contributes 17-84 % to the total DRF. East Asia has the largest contribution of 20-30 % over the Northern Hemisphere mid- and high latitudes. A 20 % perturbation of sulfate and its precursor emissions gives a sulfate incremental IRF of -0.44 W m-2. DMS has the largest contribution, explaining -0.23 W m-2 of the global sulfate incremental IRF. Incremental IRF over regions in the Southern Hemisphere with low background aerosols is more sensitive to emission perturbation than that over the polluted Northern Hemisphere.

  16. Characterization of Black and Brown Carbon Concentrations and Sources during winter in Beijing

    Science.gov (United States)

    Yan, Caiqing; Liu, Yue; Hansen, Anthony D. A.; Močnik, Griša; Zheng, Mei

    2017-04-01

    Carbonaceous aerosols, including black carbon (BC) and organic carbon (OC), play important roles in air quality, human health, and climate change. A better understanding of sources of light-absorbing carbonaceous aerosol (including black carbon and brown carbon) is particular critical for formulating emission-based control strategies and reducing uncertainties in current aerosol radiative forcing estimates. Beijing, the capital of China, has experienced serious air pollution problems and high concentrations of carbonaceous aerosols in recent years, especially during heating seasons. During November and December of 2016, several severe haze episodes occurred in Beijing, with hourly average PM2.5 mass concentration up to 400 μg/m3. In this study, concentration levels and sources of black carbon and brown carbon were investigated based on 7-wavelength Aethalometer (AE-33) with combination of other PM2.5 chemical composition information. Contributions of traffic and non-traffic emissions (e.g., coal combustion, biomass burning) were apportioned, and brown carbon was separated from black carbon. Our preliminary results showed that (1) Concentrations of BC were around 5.3±4.2 μg/m3 during the study period, with distinct diurnal variations during haze and non-haze days. (2) Traffic emissions contributed to about 37±17% of total BC, and exhibited higher contributions during non-haze days compared to haze days. (3) Coal combustion was a major source of black carbon and brown carbon in Beijing, which was more significant compared to biomass burning. Sources and the relative contributions to black carbon and brown carbon during haze and non-haze days will be further discussed.

  17. Anthropogenic lead concentrations and sources in Baltic Sea sediments based on lead isotopic composition

    International Nuclear Information System (INIS)

    Zaborska, Agata

    2014-01-01

    Highlights: • Pb concentrations reach even 147 μg/g at Gdansk Basin sediments. • Marine sediments deposited before 1860 are not contaminated by Pb. • Contemporary inventories of anthropogenic Pb in marine sediments was of 0.5–11 g for m 2 . • The lowest 206 Pb/ 207 Pb (1.165) were measured in sediments deposited between 1970s–90s. • Coal burning was always the most important Pb source in Poland. - Abstract: The Gulf of Gdańsk is influenced by heavy metals of anthropogenic origin. In this study, temporal concentration changes of Pb, Zn, Cd, and Cu were studied in six, 50 cm long sediment cores. The main aim of the study was to concentrate on the history of Pb fluxes and Pb isotopic composition ( 206 Pb/ 207 Pb and 208 Pb/ 206 Pb) to trace Pb sources. The lowest Pb concentrations (19 μg g −1 ) were measured in sediments deposited circa 1860, while the highest Pb concentrations (63–147 μg g −1 ) were measured in sediments deposited between 1960s and 70s. Pre-industrial Pb fluxes were 7 Pb m 2 year −1 , while after WWII they reached 199 Pb m 2 year −1 . Highest 206 Pb/ 207 Pb ratios (∼1.22) were measured in the oldest sediment layers, and the lowest 206 Pb/ 207 Pb ratios (∼1.165) were measured in the sediments deposited in 1970s–90s. During the period of highest Pb contamination, the anthropogenic Pb fraction reached up to 93%. A general discussion of the Pb sources, emissions, and loads for Poland is included

  18. Sources and levels of concentration of metal pollutants in Kubanni dam, Zaria, Nigeria

    Directory of Open Access Journals (Sweden)

    Butu, A.W.

    2013-06-01

    Full Text Available The paper looked at the sources and levels of concentration of metal pollutants in Kubanni dam, Zaria, Nigeria. The main sources of data for the study were sediment from four different sections of the long profile of the dam. The samples were prepared in the laboratory according to standard methods and the instrumental Neutron Activation Analysis (INAA technique was adopted in the analysis using Nigeria Research Reactor – 1 (NIRR – 1. The results of the analysis showed that 29 metal pollutants; Mg, Al, Ca, Ti, V, Mn, Dy, Na, K, As, La, Sm, Yb, U, Br, Sc, Cr, Fe, Co, Rb, Zn,Cs, Ba, Eu, Lu, Hf, Ta, Sb and Th currently exist in Kubanni dam in various levels of concentrations. The results showed that most of the metal pollutants in the dam are routed to anthropogenic activities within the dam catchment area while few are routed to geologic formation. The results further revealed that metal pollutants that their sources are traceable to refuse dumps, farmlands, public drains and effluents showed higher levels of concentration in the dam than the ones that are gradually released from the soil regolith system.

  19. [Correlations between PBDEs and thyroid hormone concentrations in adults from production source area].

    Science.gov (United States)

    Li, Ming-Yuan; Jin, Jun; Yang, Cong-Qiao; Wang, Ying; Ding, Wen-Wei; Yang, Xian-Feng; Liu, An-Ming

    2011-11-01

    Polybrominated diphenyl ethers (PBDEs) concentrations in 36 resident serum samples from PBDEs production source area were analyzed by gas chromatography/negative chemical ionization/mass spectrometry(GC-NCI-MS) method, and the concentrations of thyroid hormones were determined as well. The sigma5PBDEs (BDE-28, -47, -153, -183, -209) concentrations(lipid weight) in serum ranged from 130.3 to 4 478.4 ng x g(-1), with an average value of 529.9 ng x g(-1). BDE-209 was a dominant PBDE congener, on average accounting for 69.8% of the total PBDEs concentrations. Spearman rank correlation coefficient was calculated between PBDEs and thyroid hormone, it showed that there were high significant negative correlation between BDE-28, -47, -153, -183 and thyroid-stimulating hormone (TSH), and significant negative correlation was also found between BDE-183 and free thyroxine (fT4). Additionally, there were significant positive correlation between BDE-28, -47 and triiodothyronine (T3), as well as between BDE-28, -153, -183 and free triiodothyronine(fT3). In summary, the concentrations of PBDEs in serum in this study were at a high level, and BDE-209 was the predominant congener. The exposure to the PBDEs may affect thyroid hormone levels, and the further research should focus on the relationship between PBDEs and thyroid hormone concentrations.

  20. Characterization of mercury concentrations in snow and potential sources, Shanghai, China.

    Science.gov (United States)

    Zhang, Yanyan; Xiu, Guangli; Wu, Xuefang; Moore, Christopher W; Wang, Jiajia; Cai, Ji; Zhang, Danian; Shi, Chaoou; Zhang, Renjian

    2013-04-01

    This work focused on quantifying the total mercury (HgT) and major ion concentrations in snow samples to understand the importance of this pathway and sources of Hg deposited in Shanghai, China. Rare snow event samples were collected at 26 sites within the city of Shanghai on February 18, 2006, January 27, 2008 and January 20, 2011. The sites were distributed among four main functional area types (i.e., industrial impacted, residential impacted, traffic impacted sites and sites in the city center). Concentrations of HgT and major soluble ions, and pH values were determined for each site. Mean HgT concentrations for all sites were 78±52 ng L(-1), 277±184 ng L(-1), 189±123 ng L(-1) in 2006, 2008 and 2011, respectively. Values were higher in Shanghai than observed in other cities including Beijing which has a smaller population and is less industrial. Principle component analysis (PCA) indicated that secondary aerosols (SO4(2-), NO3(-) and NH4(+)), and biomass combustion (K(+), CH3COO(-), and HCOO(-)) were best related to mercury concentrations in the snow in 2008 and 2011. Although HYSPLIT back trajectory modeling indicated air mass transport from areas with significant coal combustion, results indicate that anthropogenic pollution from within Shanghai was the predominant source of Hg in snow. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Long term leaching of chlorinated solvents from source zones in low permeability settings with fractures

    DEFF Research Database (Denmark)

    Bjerg, Poul Løgstrup; Chambon, Julie Claire Claudia; Troldborg, Mads

    2008-01-01

    spreads to the low permeability matrix by diffusion. This results in a long term source of contamination due to back-diffusion. Leaching from such sources is further complicated by microbial degradation under anaerobic conditions to sequentially form the daughter products trichloroethylene, cis...

  2. Earthquake source parameters along the Hellenic subduction zone and numerical simulations of historical tsunamis in the Eastern Mediterranean

    Science.gov (United States)

    Yolsal-Çevikbilen, Seda; Taymaz, Tuncay

    2012-04-01

    We studied source mechanism parameters and slip distributions of earthquakes with Mw ≥ 5.0 occurred during 2000-2008 along the Hellenic subduction zone by using teleseismic P- and SH-waveform inversion methods. In addition, the major and well-known earthquake-induced Eastern Mediterranean tsunamis (e.g., 365, 1222, 1303, 1481, 1494, 1822 and 1948) were numerically simulated and several hypothetical tsunami scenarios were proposed to demonstrate the characteristics of tsunami waves, propagations and effects of coastal topography. The analogy of current plate boundaries, earthquake source mechanisms, various earthquake moment tensor catalogues and several empirical self-similarity equations, valid for global or local scales, were used to assume conceivable source parameters which constitute the initial and boundary conditions in simulations. Teleseismic inversion results showed that earthquakes along the Hellenic subduction zone can be classified into three major categories: [1] focal mechanisms of the earthquakes exhibiting E-W extension within the overriding Aegean plate; [2] earthquakes related to the African-Aegean convergence; and [3] focal mechanisms of earthquakes lying within the subducting African plate. Normal faulting mechanisms with left-lateral strike slip components were observed at the eastern part of the Hellenic subduction zone, and we suggest that they were probably concerned with the overriding Aegean plate. However, earthquakes involved in the convergence between the Aegean and the Eastern Mediterranean lithospheres indicated thrust faulting mechanisms with strike slip components, and they had shallow focal depths (h < 45 km). Deeper earthquakes mainly occurred in the subducting African plate, and they presented dominantly strike slip faulting mechanisms. Slip distributions on fault planes showed both complex and simple rupture propagations with respect to the variation of source mechanism and faulting geometry. We calculated low stress drop

  3. Source apportionment of ambient particle number concentrations in central Los Angeles using positive matrix factorization (PMF

    Directory of Open Access Journals (Sweden)

    M. H. Sowlat

    2016-04-01

    Full Text Available In this study, the positive matrix factorization (PMF receptor model (version 5.0 was used to identify and quantify major sources contributing to particulate matter (PM number concentrations, using PM number size distributions in the range of 13 nm to 10 µm combined with several auxiliary variables, including black carbon (BC, elemental and organic carbon (EC/OC, PM mass concentrations, gaseous pollutants, meteorological, and traffic counts data, collected for about 9 months between August 2014 and 2015 in central Los Angeles, CA. Several parameters, including particle number and volume size distribution profiles, profiles of auxiliary variables, contributions of different factors in different seasons to the total number concentrations, diurnal variations of each of the resolved factors in the cold and warm phases, weekday/weekend analysis for each of the resolved factors, and correlation between auxiliary variables and the relative contribution of each of the resolved factors, were used to identify PM sources. A six-factor solution was identified as the optimum for the aforementioned input data. The resolved factors comprised nucleation, traffic 1, traffic 2 (with a larger mode diameter than traffic 1 factor, urban background aerosol, secondary aerosol, and soil/road dust. Traffic sources (1 and 2 were the major contributor to PM number concentrations, collectively making up to above 60 % (60.8–68.4 % of the total number concentrations during the study period. Their contribution was also significantly higher in the cold phase compared to the warm phase. Nucleation was another major factor significantly contributing to the total number concentrations (an overall contribution of 17 %, ranging from 11.7 to 24 %, with a larger contribution during the warm phase than in the cold phase. The other identified factors were urban background aerosol, secondary aerosol, and soil/road dust, with relative contributions of approximately 12

  4. Chemical Source Localization Fusing Concentration Information in the Presence of Chemical Background Noise.

    Science.gov (United States)

    Pomareda, Víctor; Magrans, Rudys; Jiménez-Soto, Juan M; Martínez, Dani; Tresánchez, Marcel; Burgués, Javier; Palacín, Jordi; Marco, Santiago

    2017-04-20

    We present the estimation of a likelihood map for the location of the source of a chemical plume dispersed under atmospheric turbulence under uniform wind conditions. The main contribution of this work is to extend previous proposals based on Bayesian inference with binary detections to the use of concentration information while at the same time being robust against the presence of background chemical noise. For that, the algorithm builds a background model with robust statistics measurements to assess the posterior probability that a given chemical concentration reading comes from the background or from a source emitting at a distance with a specific release rate. In addition, our algorithm allows multiple mobile gas sensors to be used. Ten realistic simulations and ten real data experiments are used for evaluation purposes. For the simulations, we have supposed that sensors are mounted on cars which do not have among its main tasks navigating toward the source. To collect the real dataset, a special arena with induced wind is built, and an autonomous vehicle equipped with several sensors, including a photo ionization detector (PID) for sensing chemical concentration, is used. Simulation results show that our algorithm, provides a better estimation of the source location even for a low background level that benefits the performance of binary version. The improvement is clear for the synthetic data while for real data the estimation is only slightly better, probably because our exploration arena is not able to provide uniform wind conditions. Finally, an estimation of the computational cost of the algorithmic proposal is presented.

  5. Global source attribution of sulfate concentration and direct and indirect radiative forcing

    Directory of Open Access Journals (Sweden)

    Y. Yang

    2017-07-01

    Full Text Available The global source–receptor relationships of sulfate concentrations, and direct and indirect radiative forcing (DRF and IRF from 16 regions/sectors for years 2010–2014 are examined in this study through utilizing a sulfur source-tagging capability implemented in the Community Earth System Model (CESM with winds nudged to reanalysis data. Sulfate concentrations are mostly contributed by local emissions in regions with high emissions, while over regions with relatively low SO2 emissions, the near-surface sulfate concentrations are primarily attributed to non-local sources from long-range transport. Regional source efficiencies of sulfate concentrations are higher over regions with dry atmospheric conditions and less export, suggesting that lifetime of aerosols, together with regional export, is important in determining regional air quality. The simulated global total sulfate DRF is −0.42 W m−2, with −0.31 W m−2 contributed by anthropogenic sulfate and −0.11 W m−2 contributed by natural sulfate, relative to a state with no sulfur emissions. In the Southern Hemisphere tropics, dimethyl sulfide (DMS contributes 17–84 % to the total DRF. East Asia has the largest contribution of 20–30 % over the Northern Hemisphere mid- and high latitudes. A 20 % perturbation of sulfate and its precursor emissions gives a sulfate incremental IRF of −0.44 W m−2. DMS has the largest contribution, explaining −0.23 W m−2 of the global sulfate incremental IRF. Incremental IRF over regions in the Southern Hemisphere with low background aerosols is more sensitive to emission perturbation than that over the polluted Northern Hemisphere.

  6. Contaminant Flux Reduction Barriers for Managing Difficult to Treat Source Zones in Unconsolidated Media

    Science.gov (United States)

    2017-06-20

    formulation had a gel time of approximately 4 hours and had an estimated viscosity of 3-4 centipoise (cP).  Solutions-IES Novel Silica Gel/Veg-Oil Grout...site criteria:  Shallow depth to groundwater (ង feet [ft])  Transmissive zone preferably with an underlying clay layer  Good accessibility to...HYDROGEOLOGY The geology in the region near IS17MW03 consists of an orange to gray clay to about 12 ft below ground surface (bgs), followed by a

  7. Prediction of Groundwater Quality Improvement Down-Gradient of In Situ Permeable Treatment Barriers and Fully-Remediated Source Zones. ESTCP Cost and Performance Report

    National Research Council Canada - National Science Library

    Johnson, Paul C; Carlson, Pamela M; Dahlen, Paul

    2008-01-01

    In situ permeable treatment barriers (PTB) are designed so that contaminated groundwater flows through an engineered treatment zone within which contaminants are eliminated or the concentrations are significantly reduced...

  8. Options for cost-effectively reducing atmospheric methane concentrations from anthropogenic biomass sources

    International Nuclear Information System (INIS)

    Roos, K.F.; Jacobs, C.; Orlic, M.

    1993-01-01

    Methane is a major greenhouse gas, second only to carbon dioxide in its contribution to future global warming. Methane concentrations have more than doubled over the last two centuries and continue to rise annually. These increases are largely correlated with increasing human populations. Methane emissions from human related activities currently account for about 70 percent of annual emissions. Of these human related emissions, biomass sources account for about 75 percent and non-biomass sources about 25 percent. Because methane has a shorter lifetime than other major greenhouse gases, efforts to reduce methane emissions may fairly quickly be translated into lower atmospheric concentrations of methane and lower levels of radiative forcing. This fairly quick response would have the benefit of slowing the rate of climate change and hence allow natural ecosystems more time to adapt. Importantly, methane may be cost-effectively reduced from a number of biomass and non-biomass sources in the United States and worldwide. Methane is a valuable fuel, not just a waste by-product, and often systems may be reconfigured to reap the fuel value of the methane and more than justify the necessary expenditures. Such options for reducing methane emission from biomass sources exist for landfills, livestock manures, and ruminant livestock, and have been implemented to varying degrees in countries around the world. However, there are a number of barriers that hinder the more widespread use of technologies, including institutional, financial, regulatory, informational, and other barriers. This paper describes an array of available options that may be cost-effectively implemented to reduce methane emissions from biomass sources. This paper also discusses a number of programs that have been developed in the United States and internationally to promote the implementation of these methane reduction options and overcome existing barriers

  9. Modelling street level PM10 concentrations across Europe: source apportionment and possible futures

    Science.gov (United States)

    Kiesewetter, G.; Borken-Kleefeld, J.; Schöpp, W.; Heyes, C.; Thunis, P.; Bessagnet, B.; Terrenoire, E.; Fagerli, H.; Nyiri, A.; Amann, M.

    2015-02-01

    Despite increasing emission controls, particulate matter (PM) has remained a critical issue for European air quality in recent years. The various sources of PM, both from primary particulate emissions as well as secondary formation from precursor gases, make this a complex problem to tackle. In order to allow for credible predictions of future concentrations under policy assumptions, a modelling approach is needed that considers all chemical processes and spatial dimensions involved, from long-range transport of pollution to local emissions in street canyons. Here we describe a modelling scheme which has been implemented in the GAINS integrated assessment model to assess compliance with PM10 (PM with aerodynamic diameter dispersion calculations, and a traffic increment calculation wherever applicable. At each monitoring station fulfilling a few data coverage criteria, measured concentrations in the base year 2009 are explained to the extent possible and then modelled for the past and future. More than 1850 monitoring stations are covered, including more than 300 traffic stations and 80% of the stations which exceeded the EU air quality limit values in 2009. As a validation, we compare modelled trends in the period 2000-2008 to observations, which are well reproduced. The modelling scheme is applied here to quantify explicitly source contributions to ambient concentrations at several critical monitoring stations, displaying the differences in spatial origin and chemical composition of urban roadside PM10 across Europe. Furthermore, we analyse the predicted evolution of PM10 concentrations in the European Union until 2030 under different policy scenarios. Significant improvements in ambient PM10 concentrations are expected assuming successful implementation of already agreed legislation; however, these will not be large enough to ensure attainment of PM10 limit values in hot spot locations such as Southern Poland and major European cities. Remaining issues are

  10. Concentrations of benzene and toluene in the atmosphere of the southwestern area at the Mexico City Metropolitan Zone

    Energy Technology Data Exchange (ETDEWEB)

    Bravo, H.; Sosa, R.; Sanchez, P. [Universidad Autonoma de Mexico, Ciudad Universitaria (Mexico). Centro de Ciencias de la Atmosfera; Bueno, E.; Gonzalez, L. [Centro Nacional de Investigacion y Capacitacion Ambiental, Instituto Nacional de Ecologia, SEMARNAP, Mexico (Mexico)

    2002-08-01

    The Mexico City Metropolitan Zone (MCMZ) presents important emissions of hazardous air pollutants. It is well documented that the MCMZ suffers a critical air pollution problem due to high ozone and particulate matter concentrations. However, toxic air pollutants such as benzene and toluene have not been considered. Benzene has accumulated sufficient evidence as a human carcinogen, and the ratio benzene/toluene is an excellent indicator to evaluate control strategies efficiency. In order to evaluate the levels of these two air toxic pollutants in the MCMZ, ambient air samples were collected in canisters and analyzed with a gas chromatograph with a flame ionization detector, according to procedures described in the United States Environmental Protection Agency (USEPA) method TO-15. Quality assurance was performed collecting duplicate samples which were analyzed in replicate to quantify the precision of air-quality measurements. Three different sites located in the Southwestern area in the MCMZ were selected for the sampling: the University campus, a gas station, and a vertical condominium area, in the same neighborhood, which presents different activities. At these sites, grab air samples were collected during the morning hours (7-8 a.m.), while for the University area, 24 h integrated air samples were collected simultaneously, with grab samples. Benzene concentrations (24 h sampling) in the atmosphere around the University campus have similar present levels as in other cities of North America. Mean values in this site were about 1.7 ppb. A significant variation exists between the benzene and toluene concentrations in the studied sites, being the more critical values than those registered at the gas station (an average of 25.8 ppb and a maximum of 141 ppb of benzene). There is a fuel regulation for gasoline in Mexico, which allows a maximum of 1 percent of benzene. However, since more than 60 percent of vehicles do not have catalytic converters (models before 1991

  11. Polycyclic aromatic hydrocarbons in urban air : concentration levels and patterns and source analysis in Nairobi, Kenya

    Energy Technology Data Exchange (ETDEWEB)

    Muthini, M.; Yoshimichi, H.; Yutaka, K.; Shigeki, M. [Yokohama National Univ., Yokohama (Japan). Graduate School of Environment and Information Sciences

    2005-07-01

    Polycyclic aromatic hydrocarbons (PAHs) present in the environment are often the result of incomplete combustion processes. This paper reported concentration levels and patterns of high molecular weight PAHs in Nairobi, Kenya. Daily air samples for 30 different PAHs were collected at residential, industrial and business sites within the city. Samples were then extracted using deuterated PAH with an automated Soxhlet device. Gas chromatography and mass spectrometry (GC-MS) with a capillary column was used to analyze the extracts using a selected ion monitoring (SIM) mode. Statistical analyses were then performed. PAH concentration levels were reported for average, median, standard deviation, range, and Pearson's correlation coefficients. Data were then analyzed for sources using a principal component analysis (PCA) technique and isomer ratio analysis. Nonparametric testing was then conducted to detect inherent differences in PAH concentration data obtained from the different sites. Results showed that pyrene was the most abundant PAH. Carcinogenic PAHs were higher in high-traffic areas. The correlation coefficient between coronene and benzo(ghi)pyrene was high. The PAH isomer ratio analysis demonstrated that PAHs in Nairobi are the product of traffic emissions and oil combustion. Results also showed that PAH profiles were not well separated. It was concluded that source distinction methods must be improved in order to better evaluate PAH emissions in the city. 9 refs., 2 tabs., 1 fig.

  12. Sources of present Chernobyl-derived caesium concentrations in surface air and deposition samples

    Energy Technology Data Exchange (ETDEWEB)

    Hoetzl, H.; Rosner, G.; Winkler, R. (Gesellschaft fuer Strahlen-und Umweltforschung Munich, Neuherberg (Germany). Forschungszentrum fuer Umwelt und Gesundheit Gesellschaft fuer Strahlen- und Umweltforschung mbH Muenchen, Neuherberg (Germany). Inst. fuer Strahlenschutz)

    1992-06-01

    The sources of Chernobyl-derived caesium concentrations in air and deposition samples collected from mid-1986 to end-1990 at Munich- Neuherberg, Germany, were investigated. Local resuspension has been found to be the main source. By comparison with deposition data from other locations it is estimated that within a range from 20 Bq m[sup -2] to 60 kBq m[sup -2] of initially deposited [sup 137]Cs activity [approx]2% is re-deposited by the process of local resuspension in Austria, Germany, Japan and United Kingdom, while significantly higher total resuspension is to be expected for Denmark and Finland. Stratospheric contribution to present concentrations is shown to be negligible. This is confirmed by cross correlation analysis between the time series of [sup 137]Cs in air and precipitation before and after the Chernobyl accident and the respective time series of cosmogenic [sup 7]Be, which is an indicator of stratospheric input. Seasonal variations of caesium concentrations with maxima in winter were observed. (author). 32 refs.; 5 figs.; 1 tab.

  13. Sources of present Chernobyl-derived caesium concentrations in surface air and deposition samples

    International Nuclear Information System (INIS)

    Hoetzl, H.; Rosner, G.; Winkler, R.; Gesellschaft fuer Strahlen- und Umweltforschung mbH Muenchen, Neuherberg

    1992-01-01

    The sources of Chernobyl-derived caesium concentrations in air and deposition samples collected from mid-1986 to end-1990 at Munich- Neuherberg, Germany, were investigated. Local resuspension has been found to be the main source. By comparison with deposition data from other locations it is estimated that within a range from 20 Bq m -2 to 60 kBq m -2 of initially deposited 137 Cs activity ∼2% is re-deposited by the process of local resuspension in Austria, Germany, Japan and United Kingdom, while significantly higher total resuspension is to be expected for Denmark and Finland. Stratospheric contribution to present concentrations is shown to be negligible. This is confirmed by cross correlation analysis between the time series of 137 Cs in air and precipitation before and after the Chernobyl accident and the respective time series of cosmogenic 7 Be, which is an indicator of stratospheric input. Seasonal variations of caesium concentrations with maxima in winter were observed. (author). 32 refs.; 5 figs.; 1 tab

  14. Characteristics of carbonyl compounds in public vehicles of Beijing city: Concentrations, sources, and personal exposures

    Science.gov (United States)

    Pang, Xiaobing; Mu, Yujing

    The characteristics of carbonyl compounds (carbonyls) including concentrations, major sources, and personal exposure were investigated for 29 vehicles including taxi, bus and subway in Beijing. It was found that the taxis (Xiali, TA) and buses (Huanghe, BA) fueled by gasoline with longer service years had the higher indoor carbonyl levels (178±42.7 and 188±31.6 μg m -3) while subways energized by electricity without exhaust and the jingwa buses (BB) driven in the suburb had the lower levels with total concentrations of 98.5±26.3 and 92.1±20.3 μg m -3, respectively. Outdoor carbonyls of taxi cars and buses were nearly at the same level with their total concentrations varying from 80 to 110 μg m -3. The level of outdoor subways carbonyls was equal with the ambient air levels. Exhaust leakage, indoor material emissions, photochemical formation, and infiltration of outdoor air were considered to be the major sources to in-vehicle carbonyls. Personal exposures and cancer risk to formaldehyde and acetaldehyde were calculated for professional bus and taxi drivers, respectively. Taxi drivers had the highest cancer risk with personal exposure to formaldehyde and acetaldehyde of 212 and 243 μg day -1, respectively. The public concern should pay considerable attention to professional drivers' health.

  15. Dissolved methane concentration and flux in the coastal zone of the Southern California Bight-Mexican sector: Possible influence of wastewater

    Science.gov (United States)

    We measured dissolved methane concentrations ([CH4]) in the coastal zone of the Southern California Bight-Mexican sector (SCBMex) during two cruises: S1 in the USA–Mexico Border Area (BA) during a short rainstorm and S2 in the entire SCBMex during a drier period a few days later....

  16. Concentrations, sources and human health risk of inhalation exposure to air toxics in Edmonton, Canada.

    Science.gov (United States)

    Bari, Md Aynul; Kindzierski, Warren B

    2017-04-01

    With concern about levels of air pollutants in recent years in the Capital Region of Alberta, an investigation of ambient concentrations, sources and potential human health risk of hazardous air pollutants (HAPs) or air toxics was undertaken in the City of Edmonton over a 5-year period (2009-2013). Mean concentrations of individual HAPs in ambient air including volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs) and trace metals ranged from 0.04 to 1.73 μg/m 3 , 0.01-0.54 ng/m 3 , and 0.05-3.58 ng/m 3 , respectively. Concentrations of benzene, naphthalene, benzo(a)pyrene (BaP), arsenic, manganese and nickel were far below respective annual Alberta Ambient Air Quality Objectives. Carcinogenic and non-carcinogenic risk of air toxics were also compared with risk levels recommended by regulatory agencies. Positive matrix factorization identified six air toxics sources with traffic as the dominant contributor to total HAPs (4.33 μg/m 3 , 42%), followed by background/secondary organic aerosol (SOA) (1.92 μg/m 3 , 25%), fossil fuel combustion (0.92 μg/m 3 , 11%). On high particulate air pollution event days, local traffic was identified as the major contributor to total HAPs compared to background/SOA and fossil fuel combustion. Carcinogenic risk values of traffic, background/SOA and metals industry emissions were above the USEPA acceptable level (1 × 10 -6 ), but below a tolerable risk (1 × 10 -4 ) and Alberta benchmark (1 × 10 -5 ). These findings offer useful preliminary information about current ambient air toxics levels, dominant sources and their potential risk to public health; and this information can support policy makers in the development of appropriate control strategies if required. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Sources for increased DOC-concentrations in the groundwater downstream of the landfill Hohne (DEA)

    International Nuclear Information System (INIS)

    Bahlmann, E.; Seifert, R.; Eschenbach, A.; Kleinschmidt, V.

    2017-08-01

    Construction waste together with drilling mud and oil-contaminated soil had been deposited in the landfill Hohne from 1971. Four groundwater monitoring sites had been installed: one monitoring site upstream and three sites downstream of the landfill in three different directions. Downstream of the landfill increased concentrations of chloride, sulphate, sodium and DOC (dissolved organic carbon) had been measured over a period of years. Particularly the source of the DOC has remained unclear. Assumptions were (i) leaking of contaminants from the landfill and degradation under the landfill by microbes or plants or (ii) leaching of DOC from the soil under the landfill caused by a change in the redox potential. The determination of the DOC source was the major subject of this study.

  18. Morphological Comparison of U3O8 Ore Concentrates from Canada Key Lake and Namibia Sources

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, Daniel S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tandon, Lav [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Martinez, Patrick Thomas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-03-11

    Uranium ore concentrates from two different sources were examined using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The ore powders are referred to as Namibia (id. no. 90036, LIMS id. no. 18775) and Canada Key Lake (id. no. 90019, LIMS id. no. 18774). Earlier work identified the ores as the U₃O₈ phase of uranium oxide using x-ray diffraction. Both sets of powders were in the form of dark brown to black powder fines. However, the Canada Key Lake concentrates contained larger chunks of material on the millimeter scale that were easily visible to the unaided eye. The powders were mounted for SEM examination by hand dispersing a small amount onto conductive sticky tape. Two types of applicators were used and compared: a fine-tipped spatula and a foam-tipped applicator. The sticky tape was on a standard SEM “tee” mount, which was tapped to remove loose contamination before being inserted into the SEM.

  19. Determination, Source Identification and GIS Mapping for Nitrate Concentration in Groundwater from Bara Aquifer

    Energy Technology Data Exchange (ETDEWEB)

    Elami, G. M.; Sam, A. K.; Yagob, T. I.; Siddeeg, S. E.M.B.; Hatim, E.; Hajo, I. [Sudan Atomic Energy Commission, Sudan, Khartoum (Sudan)

    2013-07-15

    This study was carried out to determine the level of nitrate concentration in well water from Bara aquifer in north Kordofan state (west central sudan). The analysis was conducted for 69 wells from different villages within the Bara basin. Spectophotometric analysis was used to determine nitrate, nitrite and ammonia. Results revealed that nitrate concentration range was from 9.68 to 891 mg L in the sampled well with 81% exceeding the maximum permissible limits set for drinking water by WHO and SSMO. Animal waste and organic soil nitrogen were found to be the source of nitrate in these wells as indicated by {sup 15}N. The majority of wells with high nitrate are in the north and the north east part of the study area are shown by the GIS predictive map. (author)

  20. Identification of emission sources of particle-bound polycyclic aromatic hydrocarbons in the vicinity of the industrial zone of the city of Novi Sad

    Directory of Open Access Journals (Sweden)

    Jovčić Nataša S.

    2013-01-01

    Full Text Available Data on polycyclic aromatic hydrocarbons (PAHs in ambient air accessed at selected locations in the vicinity of the industrial zone of the city of Novi Sad, Serbia, have been presented and analyzed in order to determine seasonal and spatial variations and to identify emission sources of particle-bound PAHs. Previous studies have demonstrated that the major contributors of PAHs in urban areas are the emissions from vehicle exhaust, and emissions releases from industrial processes like aluminium production, creosote and wood preservation, waste incineration, cement manufacture, petrochemical and related industries, commercial heat/power production etc. The sampling campaigns have been conducted at three sampling sites, during the two 14-day periods. The first site was situated near industrial area, with a refinery, power plant and heavy-traffic road in the vicinity. The second site was located nearby the heavy traffic area, especially busy during the rush hour. The third site was residential district. Summer sampling period lasted from June 26th to July 10th 2008, while sampling of ambient air during the winter was undertaken from January 22nd to February 5th 2009. Eighty-four (84 air samples were collected using a high volume air sampler TCR Tecora H0649010/ECHO. 16 US EPA polycyclic aromatic hydrocarbons were determined in all samples using a gas chromatographer with a mass spectrometer as a detector (Shimatzu MDGC/GCMS-2010. The total average concentrations of PAHs ranged from 1.21 to 1.77 ng/m3 during the summer period and from 6.31 to 7.25 ng/m3 in the winter. Various techniques, including diagnostic ratio (DR and principal component analysis (PCA, have been used to define and evaluate potential emission sources of PAHs. Diagnostic ratio analysis indicated that vehicles, diesel or/and gasoline, industrial and combustion emissions were sources of PAHs in the vicinity of the industrial zone. Additionally, principal component analysis was used

  1. Effects of copper source and concentration on in vitro phytate phosphorus hydrolysis by phytase.

    Science.gov (United States)

    Pang, Yanfang; Applegate, Todd J

    2006-03-08

    Five copper (Cu) sources were studied at pH 2.5, 5.5, and 6.5 to determine how Cu affects phytate phosphorus (PP) hydrolysis by phytase at concentrations up to 500 mg/kg diet (60 min, 40-41 degrees C). Subsequently, Cu solubility with and without sodium phytate was measured. Adding Cu inhibited PP hydrolysis at pH 5.5 and pH 6.5 (P copper chloride and copper lysinate inhibited PP hydrolysis much less than copper sulfate pentahydrate, copper chloride, and copper citrate (P copper-phytin complexes.

  2. Energy efficiency of growing ram lambs fed concentrate-based diets with different roughage sources.

    Science.gov (United States)

    Galvani, D B; Pires, A V; Susin, I; Gouvêa, V N; Berndt, A; Chagas, L J; Dórea, J R R; Abdalla, A L; Tedeschi, L O

    2014-01-01

    Poor-quality roughages are widely used as fiber sources in concentrate-based diets for ruminants. Because roughage quality is associated with the efficiency of energy use in forage-based diets, the objective of this study was to determine whether differing the roughage source in concentrate-based diets could change the energy requirements of growing lambs. Eighty-four 1/2 Dorper × 1/2 Santa Inês ram lambs (18.0 ± 3.3 kg BW) were individually penned and divided into 2 groups according to primary source of dietary roughage: low-quality roughage (LQR; sugarcane bagasse) or medium-quality roughage (MQR; coastcross hay). Diets were formulated to be isonitrogenous (2.6% N) and to meet 20% of physically effective NDF. After a 10-d ad libitum adaptation period, 7 lambs from each group were randomly selected and slaughtered (baseline). Twenty-one lambs in each diet group were fed ad libitum and slaughtered at 25, 35, or 45 kg BW. The remaining 28 lambs (14 from each diet group) were submitted to 1 of 2 levels of feed restriction: 70% or 50% of the ad libitum intake. Retentions of body fat, N, and energy were determined. Additionally, 6 ram lambs (44.3 ± 5.6 kg BW) were kept in metabolic cages and used in a 6 × 6 Latin square experiment designed to establish the ME content of the 2 diets at the 3 levels of DM intake. There was no effect of intake level on diet ME content, but it was greater in the diet with LQR than in the diet with MQR (3.18 vs. 2.94 Mcal/kg, respectively; P energy concentrations (kcal/kg of empty BW) because of a larger visceral fat deposition (P source of forage in a concentrate-based diet for growing lambs did not change NEm and the efficiency of ME use for maintenance, which averaged 71.6 kcal/kg(0.75) of shrunk BW and 0.63, respectively. On the other hand, the greater nonfibrous carbohydrate content of the diet with LQR resulted in a 17% better efficiency of ME use for gain (P energy retention as fat (P < 0.01). This increased nutritional

  3. Comparison of sources of submicron particle number concentrations measured at two sites in Rochester, NY.

    Science.gov (United States)

    Kasumba, John; Hopke, Philip K; Chalupa, David C; Utell, Mark J

    2009-09-01

    Sources contributing to the submicron particles (100-470 nm) measured between January 2002 and December 2007 at two different New York State Department of Environmental Conservation (NYS DEC) sites in Rochester, NY were identified and apportioned using a bilinear receptor model, positive matrix factorization (PMF). Measurements of aerosol size distributions and number concentrations for particles in the size range of 10-500 nm have been made since December 2001 to date in Rochester. The measurements are being made using a scanning mobility particle sizer (SMPS) consisting of a DMA and a CPC (TSI models 3071 and 3010, respectively). From December 2001 to March 2004, particle measurements were made at the NYS DEC site in downtown Rochester, but it was moved to the eastside of Rochester in May 2004. Each measurement period was divided into three seasons i.e., winter (December, January, and February), summer (June, July, and August), and the transitional periods (March, April, May, September, October, and November) so as to avoid experimental uncertainty resulting from too large season-to-season variability in ambient temperature and solar photon intensity that would lead to unstable/non-stationary size distributions. Therefore, the seasons were analyzed independently for possible sources. Ten sources were identified at both sites and these include traffic, nucleation, residential/commercial heating, industrial emissions, secondary nitrate, ozone- rich secondary aerosol, secondary sulfate, regionally transported aerosol, and a mixed source of nucleation and traffic. These results show that the measured total outdoor particle number concentrations in Rochester generally vary with similar temporal patterns, suggesting that the central monitoring site data can be used to estimate outdoor exposure in other parts of the city.

  4. Origin of methane and sources of high concentrations in Los Angeles groundwater

    Science.gov (United States)

    Kulongoski, Justin; McMahon, Peter B.; Land, Michael; Wright, Michael; Johnson, Theodore; Landon, Matthew K.

    2018-01-01

    In 2014, samples from 37 monitoring wells at 17 locations, within or near oil fields, and one site >5 km from oil fields, in the Los Angeles Basin, California, were analyzed for dissolved hydrocarbon gas isotopes and abundances. The wells sample a variety of depths of an aquifer system composed of unconsolidated and semiconsolidated sediments under various conditions of confinement. Concentrations of methane in groundwater samples ranged from 0.002 to 150 mg/L—some of the highest concentrations reported in a densely populated urban area. The δ13C and δ2H of the methane ranged from −80.8 to −45.5 per mil (‰) and −249.8 to −134.9‰, respectively, and, along with oxidation‐reduction processes, helped to identify the origin of methane as microbial methanogenesis and CO2 reduction as its main formation pathway. The distribution of methane concentrations and isotopes is consistent with the high concentrations of methane in Los Angeles Basin groundwater originating from relatively shallow microbial production in anoxic or suboxic conditions. Source of the methane is the aquifer sediments rather than the upward migration or leakage of thermogenic methane associated with oil fields in the basin.

  5. The source of phosphate in the oxidation zone of ore deposits: Evidence from oxygen isotope compositions of pyromorphite

    Science.gov (United States)

    Burmann, Fabian; Keim, Maximilian F.; Oelmann, Yvonne; Teiber, Holger; Marks, Michael A. W.; Markl, Gregor

    2013-12-01

    Pyromorphite (Pb5[PO4]3Cl) is an abundant mineral in oxidized zones of lead-bearing ore deposits and due to its very low solubility product effectively binds Pb during supergene alteration of galena (PbS). The capacity of a soil or near-surface fluid to immobilize dissolved Pb depends critically on the availability of phosphate in this soil or fluid. Potential phosphorus sources in soil include (i) release during biological processes, i.e. leaching from litter/lysis of microbial cells (after intracellular enzyme activity) in soil and hydrolysis from soil organic matter by extracellular enzymes and (ii) inorganic phosphate from the dissolution of apatite in the adjacent basement rocks. Intracellular enzyme activity in plants/microorganisms associated with kinetic fractionation produces an oxygen isotope composition distinctly different from inorganic processes in soil. This study presents the first oxygen isotope data for phosphate (δ18OP) in pyromorphite and a comprehensive data set for apatite from crystalline rocks. We investigated 38 pyromorphites from 26 localities in the Schwarzwald (Southwest Germany) and five samples from localities outside the Schwarzwald in addition to 12 apatite separates from gneissic and granitic host rocks. Pyromorphites had δ18OP values between +10‰ and +19‰, comparable to literature data on δ18OP in the readily available P fraction in soil (resin-extractable P) from which minerals potentially precipitate in soils. δ18OP values below the range of equilibrium isotope fractionation can be attributed either to apatites that formed geochemically (δ18OP of apatites:+6‰ to +9‰) or less likely to biological processes (extracellular enzyme activity). However, for most of our samples isotopic equilibrium with ambient water was indicated, which suggests biological activity. Therefore, we conclude that the majority of pyromorphites in oxidized zones of ore bodies formed from biologically cycled phosphate. This study highlights that

  6. Inverse modeling of the Chernobyl source term using atmospheric concentration and deposition measurements

    Science.gov (United States)

    Evangeliou, Nikolaos; Hamburger, Thomas; Cozic, Anne; Balkanski, Yves; Stohl, Andreas

    2017-07-01

    This paper describes the results of an inverse modeling study for the determination of the source term of the radionuclides 134Cs, 137Cs and 131I released after the Chernobyl accident. The accident occurred on 26 April 1986 in the Former Soviet Union and released about 1019 Bq of radioactive materials that were transported as far away as the USA and Japan. Thereafter, several attempts to assess the magnitude of the emissions were made that were based on the knowledge of the core inventory and the levels of the spent fuel. More recently, when modeling tools were further developed, inverse modeling techniques were applied to the Chernobyl case for source term quantification. However, because radioactivity is a sensitive topic for the public and attracts a lot of attention, high-quality measurements, which are essential for inverse modeling, were not made available except for a few sparse activity concentration measurements far from the source and far from the main direction of the radioactive fallout. For the first time, we apply Bayesian inversion of the Chernobyl source term using not only activity concentrations but also deposition measurements from the most recent public data set. These observations refer to a data rescue attempt that started more than 10 years ago, with a final goal to provide available measurements to anyone interested. In regards to our inverse modeling results, emissions of 134Cs were estimated to be 80 PBq or 30-50 % higher than what was previously published. From the released amount of 134Cs, about 70 PBq were deposited all over Europe. Similar to 134Cs, emissions of 137Cs were estimated as 86 PBq, on the same order as previously reported results. Finally, 131I emissions of 1365 PBq were found, which are about 10 % less than the prior total releases. The inversion pushes the injection heights of the three radionuclides to higher altitudes (up to about 3 km) than previously assumed (≈ 2.2 km) in order to better match both concentration

  7. Inverse modeling of the Chernobyl source term using atmospheric concentration and deposition measurements

    Directory of Open Access Journals (Sweden)

    N. Evangeliou

    2017-07-01

    Full Text Available This paper describes the results of an inverse modeling study for the determination of the source term of the radionuclides 134Cs, 137Cs and 131I released after the Chernobyl accident. The accident occurred on 26 April 1986 in the Former Soviet Union and released about 1019 Bq of radioactive materials that were transported as far away as the USA and Japan. Thereafter, several attempts to assess the magnitude of the emissions were made that were based on the knowledge of the core inventory and the levels of the spent fuel. More recently, when modeling tools were further developed, inverse modeling techniques were applied to the Chernobyl case for source term quantification. However, because radioactivity is a sensitive topic for the public and attracts a lot of attention, high-quality measurements, which are essential for inverse modeling, were not made available except for a few sparse activity concentration measurements far from the source and far from the main direction of the radioactive fallout. For the first time, we apply Bayesian inversion of the Chernobyl source term using not only activity concentrations but also deposition measurements from the most recent public data set. These observations refer to a data rescue attempt that started more than 10 years ago, with a final goal to provide available measurements to anyone interested. In regards to our inverse modeling results, emissions of 134Cs were estimated to be 80 PBq or 30–50 % higher than what was previously published. From the released amount of 134Cs, about 70 PBq were deposited all over Europe. Similar to 134Cs, emissions of 137Cs were estimated as 86 PBq, on the same order as previously reported results. Finally, 131I emissions of 1365 PBq were found, which are about 10 % less than the prior total releases. The inversion pushes the injection heights of the three radionuclides to higher altitudes (up to about 3 km than previously assumed (≈ 2.2 km in order

  8. NEAR- AND FAR-FIELD RESPONSE TO COMPACT ACOUSTIC SOURCES IN STRATIFIED CONVECTION ZONES

    International Nuclear Information System (INIS)

    Cally, Paul S.

    2013-01-01

    The role of the acoustic continuum associated with compact sources in the Sun's interior wave field is explored for a simple polytropic model. The continuum produces a near-field acoustic structure—the so-called acoustic jacket—that cannot be represented by a superposition of discrete normal modes. Particular attention is paid to monochromatic point sources of various frequency and depth, and to the surface velocity power that results, both in the discrete f- and p-mode spectrum and in the continuum. It is shown that a major effect of the continuum is to heal the surface wave field produced by compact sources, and therefore to hide them from view. It is found that the continuous spectrum is not a significant contributor to observable inter-ridge seismic power.

  9. NEAR- AND FAR-FIELD RESPONSE TO COMPACT ACOUSTIC SOURCES IN STRATIFIED CONVECTION ZONES

    Energy Technology Data Exchange (ETDEWEB)

    Cally, Paul S., E-mail: paul.cally@monash.edu [Monash Centre for Astrophysics and School of Mathematical Sciences, Monash University, Clayton, Victoria 3800 (Australia)

    2013-05-01

    The role of the acoustic continuum associated with compact sources in the Sun's interior wave field is explored for a simple polytropic model. The continuum produces a near-field acoustic structure-the so-called acoustic jacket-that cannot be represented by a superposition of discrete normal modes. Particular attention is paid to monochromatic point sources of various frequency and depth, and to the surface velocity power that results, both in the discrete f- and p-mode spectrum and in the continuum. It is shown that a major effect of the continuum is to heal the surface wave field produced by compact sources, and therefore to hide them from view. It is found that the continuous spectrum is not a significant contributor to observable inter-ridge seismic power.

  10. Chromium(VI) generation in vadose zone soils and alluvial sediments of the southwestern Sacramento Valley, California: a potential source of geogenic Cr(VI) to groundwater

    Science.gov (United States)

    Mills, Christopher T.; Morrison, Jean M.; Goldhaber, Martin B.; Ellefsen, Karl J.

    2011-01-01

    very small fraction of the total solid phase Cr, they are a potentially important source for Cr(VI) to groundwater. Enhanced groundwater recharge through the vadose zone due to irrigation could carry Cr(VI) from the vadose zone to the groundwater and may be the mechanism responsible for the correlation observed between elevated Cr(VI) and NO3- source concentrations in previously published data for valley groundwaters. Incubation of a valley subsoil showed a Cr(VI) production rate of 24 μg kg−1 a−1 suggesting that field Cr(VI) concentrations could be regenerated annually. Increased Cr(VI) production rates in H+-amended soil incubations indicate that soil acidification processes such as nitrification of ammonium in fertilizers could potentially increase the occurrence of geogenic Cr(VI) in groundwater. Thus, despite the natural origin of the Cr, Cr(VI) generation in the Sacramento Valley soils and sediments has the potential to be influenced by human activities.

  11. Suppliers' activities within the controlled zones of licensees handling ionizing radiation sources. Recommendations

    International Nuclear Information System (INIS)

    1999-01-01

    The Recommendations are intended to lay down a unified procedure for preparing licence applications related to ionizing radiation source handling, including the required documentation. The guidelines were set up based on documents of the Dukovany nuclear power plant and adapted to serve the Temelin nuclear power plant and other workplaces handling ionizing radiation sources as well. Selected provisions of applicable legislation are reproduced, and responsibilities are described. The major part of the publication is constituted by model documents, particularly a model Quality Assurance Programme. (P.A.)

  12. Fundamental Study of the Delivery of Nanoiron to DNAPL Source Zones in Naturally Heterogeneous Field Systems

    Science.gov (United States)

    2012-09-01

    RDE rotating speed .....................................................................................105 7.8.7 Effect of NZVI concentration...electrolytes (electrolyte names are presented in the legend). [NZVI] = 200 mg/L. RDE rotating speed = 4000 rpm...105 Figure 7.8.6. Temporal evolution of ORP (Pt vs. Ag/AgCl) of NZVI suspensions at various RDE rotating speeds (presented in the

  13. Estimate of main local sources to ambient ultrafine particle number concentrations in an urban area

    Science.gov (United States)

    Rahman, Md Mahmudur; Mazaheri, Mandana; Clifford, Sam; Morawska, Lidia

    2017-09-01

    Quantifying and apportioning the contribution of a range of sources to ultrafine particles (UFPs, D oil refineries, and seaport) sources to the total ambient particle number concentration (PNC) in a busy, inner-city area in Brisbane, Australia using Bayesian statistical modelling and other exploratory tools. The Bayesian model was trained on the PNC data on days where NP formations were known to have not occurred, hourly traffic counts, solar radiation data, and smooth daily trend. The model was applied to apportion and quantify the contribution of NP formations and local traffic and non-traffic sources to UFPs. The data analysis incorporated long-term measured time-series of total PNC (D ≥ 6 nm), particle number size distributions (PSD, D = 8 to 400 nm), PM2.5, PM10, NOx, CO, meteorological parameters and traffic counts at a stationary monitoring site. The developed Bayesian model showed reliable predictive performances in quantifying the contribution of NP formation events to UFPs (up to 4 × 104 particles cm- 3), with a significant day to day variability. The model identified potential NP formation and no-formations days based on PNC data and quantified the sources contribution to UFPs. Exploratory statistical analyses show that total mean PNC during the middle of the day was up to 32% higher than during peak morning and evening traffic periods, which were associated with NP formation events. The majority of UFPs measured during the peak traffic and NP formation periods were between 30-100 nm and smaller than 30 nm, respectively. To date, this is the first application of Bayesian model to apportion different sources contribution to UFPs, and therefore the importance of this study is not only in its modelling outcomes but in demonstrating the applicability and advantages of this statistical approach to air pollution studies.

  14. Nitrate concentration in spring water at the Nogawa basin and its possible source

    International Nuclear Information System (INIS)

    Yoshida, Kazuhiro; Ogura, Norio

    1978-01-01

    Fluctuation of nitrate concentration in spring water at the Nogawa basin was studied during 1976 - 1977, and the possible source of nitrate nitrogen was discussed. Nitrate concentration in spring water at the station N-O in Kokubunji, Tokyo ranged from 360 to 574 μg at/l with an average value of 502 μg at/l. It seemed that the effluent of spring water at N-O was influenced by rainfall within a short period. A laboratory experiment on production of nitrate in soil showed that ammonium nitrogen added to fresh soil was transformed quantitatively to nitrate nitrogen during 23 days incubation. Thd sup(delta15)N value of nitrate nitrogen in spring water (+0.89%) was similar to that of ammonium nitrogen in sewage (+0.82%) discharging into the Nogawa River. In the area near N-O, domestic wastes have been discharged into the Nogawa River by simple sewers or percolated downward through the soil. These results suggest that one of the main source of nitrate nitrogen in spring water is ammonium and organic nitrogen in domestic wastes. (author)

  15. Regional Integrated Tenets to Reinforce the Safety and Security of Radioactive Sources (ClearZone)

    International Nuclear Information System (INIS)

    Salzer, P.

    2003-01-01

    The EURATOM Research and Training Programme on Nuclear Energy includes 2 main fields - fusion energy research and management of radioactive waste, radiation protection and other activities of nuclear technology and safety.Seven instruments (mechanisms) for projects management are used - 'Network of Excellence' (NOE); 'Integrated Project' (IP); 'Specific Targeted Research Project' or 'Specific Targeted Training Project' (STREP); 'Co-ordination Action' (CA); Actions to Promote and Develop Human Resources and Mobility Specific Support Actions; Integrated Infrastructure Initiatives. Two consecutive sub-projects are proposed: 'small' - countries of the Visegrad four + Austrian participant -within the 6th FP 'Specific Supported Actions' and 'large' - participation of more countries in the region - more oriented to practical implementation of the 'small' project findings - intention to use the 6th Framework Programme resources to co-financing the implementation activities. The main objectives are: to create effective lines of defense (prevention -detection - categorization - transport - storage) against malicious use of radioactive sources; to achieve and maintain a high level of safety and security of radioactive sources; to arise the radioactive sources management safety and security culture at the Central European region. Consortium of 11 organisations from Czech Republic, Slovak Republic, Austria, Hungary and Poland is established for the Project implementation. The Project task are grouped in the following areas: legislation, infrastructure, practices; metallurgical industry, cross border control; instrumentation and metrology; information system

  16. Improving Effectiveness of Bioremediation at DNAPL Source Zone Sites by Applying Partitioning Electron Donors (PEDs)

    Science.gov (United States)

    2014-07-01

    at an effective concentration at the DNAPL:water interface for the growth of and consumption by dechlorinating biomass . In heterogeneous geological...the promotion of dechlorinating biomass growth close to the DNAPL, which results in sustained enhanced DNAPL dissolution rates. This approach...fine- grained sands with varying amounts of shell fragments, with a hydraulic conductivity of 3 ft/day in the 30 to 45 ft BLS interval; • 45 to 48 ft

  17. Benzonphenone-type UV filters in urine of Chinese young adults: Concentration, source and exposure

    International Nuclear Information System (INIS)

    Gao, Chong-jing; Liu, Li-yan; Ma, Wan-li; Zhu, Ning-zheng; Jiang, Ling; Li, Yi-Fan; Kannan, Kurunthachalam

    2015-01-01

    Benzophenone (BP)-type UV filters are commonly used in our daily life. 2-hydroxy-4-methoxy benzophenone (BP-3), 4-hydroxy benzophenone (4-HBP), 2,4-dihydroxy benzophenone (BP-1), 2,2′,4,4′-tetrahydroxy benzophenone (BP-2) and 2,2′-dihydroxy-4-methoxy benzophenone (BP-8) were measured in urine samples from Chinese young adults. The results indicated that Chinese young adults were widely exposed to BP-3, BP-1, and 4-HBP, with the median concentrations of 0.55, 0.21, and 0.08 ng/mL, respectively. No significant difference was found between males and females, between urban and rural population. The correlations between urinary concentrations provided important indications for sources and metabolic pathways of target compounds. The estimated daily excretion doses of BP-3, 4-HBP, BP-1, BP-2 and BP-8 were 27.2, 2.24, 5.86, 0.76 and 0.30 ng/kg-bw/day, respectively. The ratio of exposure to excretion must be considered for the exposure assessment with chemicals based on urine measurement. This is the first nationwide study on BP-derivatives with young adults in China. - Highlights: • Five BP-derivatives in urine were analyzed for Chinese young adults over China. • No difference was found between males and females, between urban and rural groups. • Concentration correlation provide indications for sources and metabolic pathways. • Ratio of exposure to excretion must be considered for the exposure assessment. - Benzophenone (BP)-type UV filters were frequently detected in urine samples from Chinese young adults, indicating their wide applications in China

  18. Coupling meteorology, metal concentrations, and Pb isotopes for source attribution in archived precipitation samples.

    Science.gov (United States)

    Graney, Joseph R; Landis, Matthew S

    2013-03-15

    A technique that couples lead (Pb) isotopes and multi-element concentrations with meteorological analysis was used to assess source contributions to precipitation samples at the Bondville, Illinois USA National Trends Network (NTN) site. Precipitation samples collected over a 16month period (July 1994-October 1995) at Bondville were parsed into six unique meteorological flow regimes using a minimum variance clustering technique on back trajectory endpoints. Pb isotope ratios and multi-element concentrations were measured using high resolution inductively coupled plasma-sector field mass spectrometry (ICP-SFMS) on the archived precipitation samples. Bondville is located in central Illinois, ~250km downwind from smelters in southeast Missouri. The Mississippi Valley Type ore deposits in Missouri provided a unique multi-element and Pb isotope fingerprint for smelter emissions which could be contrasted to industrial emissions from the Chicago and Indianapolis urban areas (~125km north and east, of Bondville respectively) and regional emissions from electric utility facilities. Differences in Pb isotopes and element concentrations in precipitation corresponded to flow regime. Industrial sources from urban areas, and thorogenic Pb from coal use, could be differentiated from smelter emissions from Missouri by coupling Pb isotopes with variations in element ratios and relative mass factors. Using a three endmember mixing model based on Pb isotope ratio differences, industrial processes in urban airsheds contributed 56±19%, smelters in southeast Missouri 26±13%, and coal combustion 18±7%, of the Pb in precipitation collected in Bondville in the mid-1990s. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Decline in Chinese lake phosphorus concentration accompanied by shift in sources since 2006

    Science.gov (United States)

    Tong, Yindong; Zhang, Wei; Wang, Xuejun; Couture, Raoul-Marie; Larssen, Thorjørn; Zhao, Yue; Li, Jing; Liang, Huijiao; Liu, Xueyan; Bu, Xiaoge; He, Wei; Zhang, Qianggong; Lin, Yan

    2017-07-01

    Domestic wastewater and agricultural activities are important sources of nutrient pollutants such as phosphorus and nitrogen. Upon reaching freshwater, these nutrients can lead to extensive growth of harmful algae, which results in eutrophication. Many Chinese lakes are subject to such eutrophication, especially in highly polluted areas, and as such, understanding nutrient fluxes to these lakes offers insights into the varying processes governing pollutant fluxes as well as lake water quality. Here we analyse water quality data, recorded between 2006 and 2014 in 862 freshwater lakes in four geographical regions of China, to assess the input of phosphorus from human activity. We find that improvements in sanitation of both rural and urban domestic wastewater have resulted in large-scale declines in lake phosphorus concentrations in the most populated parts of China. In more sparsely populated regions, diffuse sources such as aquaculture and livestock farming offset this decline. Anthropogenic deforestation and soil erosion may also offset decreases in point sources of pollution. In the light of these regional differences, we suggest that a spatially flexible set of policies for water quality control would be beneficial for the future health of Chinese lakes.

  20. Determination, source identification and GIS mapping for nitrate concentration in ground water from Bara aquifer

    International Nuclear Information System (INIS)

    Elfaki Taha, G. M. E.

    2010-09-01

    The study was carried-out determine the level of nitrate concentration in well water from Bara aquifer in North Kordofan State. The analysis was conducted for 69 wells from different villages within Bara basin. Physical characteristics were measured including pH, electrical conductivity and dissolved oxygen. Spectrophotometric analysis was used to determine nitrate, nitrite and ammonia. Chloride and hardness were determined telemetrically and flame photometer was used for major elements namely sodium and potassium, whereas atomic absorption spectroscopy was used for trace elements namely iron, manganese, zinc and copper. Results revealed that nitrate concentration range from 9.68 to 891 mg/1 in sampled wells with 81% exceeding the maximum permissible limits set for drinking water by WHO and SSMO. Animal waste and organic soil nitrogen were found to be the sources of nitrate in these wells as indicated by 15 N%. Majority of wells with high nitrate are located in the north and the north-east part of the study area as shown by GIS predictive map. On the average, the concentrations of sodium, potassium, calcium, magnesium, iron, manganese, zinc and copper were found to be within WHO limits for drinking water. (Author)

  1. Probability density function modeling of scalar mixing from concentrated sources in turbulent channel flow

    Science.gov (United States)

    Bakosi, J.; Franzese, P.; Boybeyi, Z.

    2007-11-01

    Dispersion of a passive scalar from concentrated sources in fully developed turbulent channel flow is studied with the probability density function (PDF) method. The joint PDF of velocity, turbulent frequency and scalar concentration is represented by a large number of Lagrangian particles. A stochastic near-wall PDF model combines the generalized Langevin model of Haworth and Pope [Phys. Fluids 29, 387 (1986)] with Durbin's [J. Fluid Mech. 249, 465 (1993)] method of elliptic relaxation to provide a mathematically exact treatment of convective and viscous transport with a nonlocal representation of the near-wall Reynolds stress anisotropy. The presence of walls is incorporated through the imposition of no-slip and impermeability conditions on particles without the use of damping or wall-functions. Information on the turbulent time scale is supplied by the gamma-distribution model of van Slooten et al. [Phys. Fluids 10, 246 (1998)]. Two different micromixing models are compared that incorporate the effect of small scale mixing on the transported scalar: the widely used interaction by exchange with the mean and the interaction by exchange with the conditional mean model. Single-point velocity and concentration statistics are compared to direct numerical simulation and experimental data at Reτ=1080 based on the friction velocity and the channel half width. The joint model accurately reproduces a wide variety of conditional and unconditional statistics in both physical and composition space.

  2. Modelling street level PM10 concentrations across Europe: source apportionment and possible futures

    Directory of Open Access Journals (Sweden)

    G. Kiesewetter

    2015-02-01

    Full Text Available Despite increasing emission controls, particulate matter (PM has remained a critical issue for European air quality in recent years. The various sources of PM, both from primary particulate emissions as well as secondary formation from precursor gases, make this a complex problem to tackle. In order to allow for credible predictions of future concentrations under policy assumptions, a modelling approach is needed that considers all chemical processes and spatial dimensions involved, from long-range transport of pollution to local emissions in street canyons. Here we describe a modelling scheme which has been implemented in the GAINS integrated assessment model to assess compliance with PM10 (PM with aerodynamic diameter 10 across Europe. Furthermore, we analyse the predicted evolution of PM10 concentrations in the European Union until 2030 under different policy scenarios. Significant improvements in ambient PM10 concentrations are expected assuming successful implementation of already agreed legislation; however, these will not be large enough to ensure attainment of PM10 limit values in hot spot locations such as Southern Poland and major European cities. Remaining issues are largely eliminated in a scenario applying the best available emission control technologies to the maximal technically feasible extent.

  3. Near-source attenuation of high-frequency body waves beneath the New Madrid Seismic Zone

    Science.gov (United States)

    Pezeshk, Shahram; Sedaghati, Farhad; Nazemi, Nima

    2018-03-01

    Attenuation characteristics in the New Madrid Seismic Zone (NMSZ) are estimated from 157 local seismograph recordings out of 46 earthquakes of 2.6 ≤ M ≤ 4.1 with hypocentral distances up to 60 km and focal depths down to 25 km. Digital waveform seismograms were obtained from local earthquakes in the NMSZ recorded by the Center for Earthquake Research and Information (CERI) at the University of Memphis. Using the coda normalization method, we tried to determine Q values and geometrical spreading exponents at 13 center frequencies. The scatter of the data and trade-off between the geometrical spreading and the quality factor did not allow us to simultaneously derive both these parameters from inversion. Assuming 1/ R 1.0 as the geometrical spreading function in the NMSZ, the Q P and Q S estimates increase with increasing frequency from 354 and 426 at 4 Hz to 729 and 1091 at 24 Hz, respectively. Fitting a power law equation to the Q estimates, we found the attenuation models for the P waves and S waves in the frequency range of 4 to 24 Hz as Q P = (115.80 ± 1.36) f (0.495 ± 0.129) and Q S = (161.34 ± 1.73) f (0.613 ± 0.067), respectively. We did not consider Q estimates from the coda normalization method for frequencies less than 4 Hz in the regression analysis since the decay of coda amplitude was not observed at most bandpass filtered seismograms for these frequencies. Q S/ Q P > 1, for 4 ≤ f ≤ 24 Hz as well as strong intrinsic attenuation, suggest that the crust beneath the NMSZ is partially fluid-saturated. Further, high scattering attenuation indicates the presence of a high level of small-scale heterogeneities inside the crust in this region.

  4. New insight into the distribution pattern, levels, and risk diagnosis of FRs in indoor and outdoor air at low- and high-altitude zones of Pakistan: Implications for sources and exposure.

    Science.gov (United States)

    Khan, Muhammad Usman; Besis, Athanasios; Li, Jun; Zhang, Gan; Malik, Riffat Naseem

    2017-10-01

    Data regarding flame retardants (FRs) in indoor and outdoor air and their exposure to population are scarce and especially unknown in the case of Pakistan. The current study was designed to probe FR concentrations and distribution pattern in indoor and outdoor air at different altitudinal zones (DAZs) of Pakistan with special emphasis on their risk to the exposed population. In this study, passive air samplers for the purpose of FR deposition were deployed in indoor and outdoor air at the industrial, rural, and background/colder zones/sites. All the indoor and outdoor air samples collected from DAZs were analyzed for the target FRs (9.30-472.30 pg/m 3 ), showing a decreasing trend as follows: ∑NBFRs > ∑PBDEs > ∑DP. However, significant correlations among FRs in the indoor and outdoor air at DAZs signified a similar source of FR origin that is used in different consumer goods. Furthermore, air mass trajectories revealed that movement of air over industrial area sources influenced concentrations of FRs at rural sites. The FR concentrations, estimated daily intake (EDI) and the hazard quotient (HQ), were recorded to be higher in toddlers than those in adults. In addition, indoor air samples showed higher FR levels, EDI and HQ, than outdoor air samples. An elevated FR concentrations and their prevalent exposure risks were recorded in the industrial zones followed by rural and background zones. The HQ for BDE-47 and BDE-99 in the indoor and outdoor air samples at different industrial and rural sites were recorded to be >1 in toddlers and adults, this further warrants a health risk in the population. However, FR investigation in indoor and outdoor air samples will provide a baseline data in Pakistan to take further steps by the government and agencies for its implementations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Contributions of Organic Sources to Atmospheric Aerosol Particle Concentrations and Growth

    Science.gov (United States)

    Russell, L. M.

    2017-12-01

    Organic molecules are important contributors to aerosol particle mass and number concentrations through primary emissions as well as secondary growth in the atmosphere. New techniques for measuring organic aerosol components in atmospheric particles have improved measurements of this contribution in the last 20 years, including Scanning Transmission X-ray Microscopy Near Edge X-ray Absorption Fine Structure (STXM-NEXAFS), Fourier Transform Infrared spectroscopy (FTIR), and High-Resolution Aerosol Mass Spectrometry (AMS). STXM-NEXAFS individual aerosol particle composition illustrated the variety of morphology of organic components in marine aerosols, the inherent relationships between organic composition and shape, and the links between atmospheric aerosol composition and particles produced in smog chambers. This type of single particle microscopy has also added to size distribution measurements by providing evidence of how surface-controlled and bulk-controlled processes contribute to the growth of particles in the atmosphere. FTIR analysis of organic functional groups are sufficient to distinguish combustion, marine, and terrestrial organic particle sources and to show that each of those types of sources has a surprisingly similar organic functional group composition over four different oceans and four different continents. Augmenting the limited sampling of these off-line techniques with side-by-side inter-comparisons to online AMS provides complementary composition information and consistent quantitative attribution to sources (despite some clear method differences). Single-particle AMS techniques using light scattering and event trigger modes have now also characterized the types of particles found in urban, marine, and ship emission aerosols. Most recently, by combining with off-line techniques, single particle composition measurements have separated and quantified the contributions of organic, sulfate and salt components from ocean biogenic and sea spray

  6. Chromium(VI) generation in vadose zone soils and alluvial sediments of the southwestern Sacramento Valley, California: A potential source of geogenic Cr(VI) to groundwater

    International Nuclear Information System (INIS)

    Mills, Christopher T.; Morrison, Jean M.; Goldhaber, Martin B.; Ellefsen, Karl J.

    2011-01-01

    g kg -1 , representing a minute fraction of total Cr. Chromium(VI) content was typically below detection in surface soils (top 10 cm) where soil organic matter was high, and increased with increasing depth in the soil auger cores as organic matter decreased. Maximum concentrations of Cr(VI) were up to 3 times greater in the deeper drill core samples than the shallow auger cores. Although Cr(VI) in these vadose zone soils and sediments was only a very small fraction of the total solid phase Cr, they are a potentially important source for Cr(VI) to groundwater. Enhanced groundwater recharge through the vadose zone due to irrigation could carry Cr(VI) from the vadose zone to the groundwater and may be the mechanism responsible for the correlation observed between elevated Cr(VI) and NO 3 - concentrations in previously published data for valley groundwaters. Incubation of a valley subsoil showed a Cr(VI) production rate of 24 μg kg -1 a -1 suggesting that field Cr(VI) concentrations could be regenerated annually. Increased Cr(VI) production rates in H + -amended soil incubations indicate that soil acidification processes such as nitrification of ammonium in fertilizers could potentially increase the occurrence of geogenic Cr(VI) in groundwater. Thus, despite the natural origin of the Cr, Cr(VI) generation in the Sacramento Valley soils and sediments has the potential to be influenced by human activities.

  7. Chromium(VI) generation in vadose zone soils and alluvial sediments of the southwestern Sacramento Valley, California: A potential source of geogenic Cr(VI) to groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Mills, Christopher T., E-mail: cmills@usgs.gov [United States Geological Survey, Crustal Geophysics and Geochemistry Science Center, Denver Federal Center, MS 964D, Denver, CO 80225 (United States); Morrison, Jean M.; Goldhaber, Martin B.; Ellefsen, Karl J. [United States Geological Survey, Crustal Geophysics and Geochemistry Science Center, Denver Federal Center, MS 964D, Denver, CO 80225 (United States)

    2011-08-15

    from 0 to 42 {mu}g kg{sup -1}, representing a minute fraction of total Cr. Chromium(VI) content was typically below detection in surface soils (top 10 cm) where soil organic matter was high, and increased with increasing depth in the soil auger cores as organic matter decreased. Maximum concentrations of Cr(VI) were up to 3 times greater in the deeper drill core samples than the shallow auger cores. Although Cr(VI) in these vadose zone soils and sediments was only a very small fraction of the total solid phase Cr, they are a potentially important source for Cr(VI) to groundwater. Enhanced groundwater recharge through the vadose zone due to irrigation could carry Cr(VI) from the vadose zone to the groundwater and may be the mechanism responsible for the correlation observed between elevated Cr(VI) and NO{sub 3}{sup -} concentrations in previously published data for valley groundwaters. Incubation of a valley subsoil showed a Cr(VI) production rate of 24 {mu}g kg{sup -1} a{sup -1} suggesting that field Cr(VI) concentrations could be regenerated annually. Increased Cr(VI) production rates in H{sup +}-amended soil incubations indicate that soil acidification processes such as nitrification of ammonium in fertilizers could potentially increase the occurrence of geogenic Cr(VI) in groundwater. Thus, despite the natural origin of the Cr, Cr(VI) generation in the Sacramento Valley soils and sediments has the potential to be influenced by human activities.

  8. Organic contamination of surface sediments in the metropolitan coastal zone of Athens, Greece: sources, degree, and ecological risk.

    Science.gov (United States)

    Kapsimalis, V; Panagiotopoulos, I P; Talagani, P; Hatzianestis, I; Kaberi, H; Rousakis, G; Kanellopoulos, T D; Hatiris, G A

    2014-03-15

    Bottom sediments represent a crucial component of the marine environment, since they constitute a habitat, a trophic resource, and a spawning place for various organisms. Unfortunately, the sediments of urban coastal areas are deeply impacted by anthropogenic activities that degrade their quality. In the Drapetsona-Keratsini metropolitan coastal zone of Athens, current industrial and shipping activities together with the effluents from a sewage outfall, which was in operation in the past, have resulted in one of the most contaminated sedimentary environments, in terms of organic compound loads, in Mediterranean. Exceptionally high concentrations of aliphatic hydrocarbons (up to 4457 μg g⁻¹), carcinogenic PAHs (up to 7284 ng g⁻¹), and organochlorines (up to 544 ng g⁻¹ for PCBs; up to 208 ng g⁻¹ for DDTs) constitute a major threat to the marine life of the associated Saronikos Gulf. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Variability of Surface pollutants and aerosol concentration over Abu Dhabi, UAE - sources, transport and current levels

    Science.gov (United States)

    Phanikumar, Devulapalli V.; Basha, Ghouse; Ouarda, Taha B. M. J.

    2015-04-01

    In the view of recent economic, industrial, and rapid development, Abu Dhabi (24.4oN; 54.4oE; 27m msl) has become one of the most populated regions in the world despite of extreme heat, frequent dust storms, and with distinctive topography. The major sources of air pollution are from the dust and sand storms, greenhouse gas emissions, and to some extent from industrial pollution. In order to realize the accurate and comprehensive understanding of air quality and plausible sources over this region, we have made a detailed analysis of three years simultaneous measurements during 2011-13 of pollutants such as O3, SO2, NO2, CO, and PM10 concentrations. Diurnal variation of meteorological parameters such as temperature and wind speed/relative humidity clearly shows daytime maximum/minimum in summer followed by pre-monsoon, post-monsoon and winter. The prevailing winds over this region are mostly from northwesterly direction (Shamal wind). Diurnal wind pattern showed a clear contrast with the majority of the wind pattern during nighttime and early morning is from the westerly/northwesterly and daytime is from southwesterly/southeasterly directions. The diurnal pattern of O3 shows minimum during 08 LT and increases thereafter reaching maximum at 17 LT and decreases during nighttime. However, the diurnal pattern of SO2 and NO2 show a peak at ~ 08 LT and dip at ~ 14 LT during all the seasons with some variability in each season. On the other hand, the diurnal pattern of CO shows a peculiar picture of elevated levels during daytime peaking at ~ 10 LT (prominent in summer and post-monsoon) followed by a sharp decrease and minimum is ~14 LT. PM10 concentration has an early morning peak at ~ 02 LT and then decreases to a minimum value at ~11 LT and again increases in the afternoon hours (maximum at ~17 LT) depicting a forenoon-afternoon asymmetry. Monthly variation of PM10 shows maximum in pre-monsoon season and minimum in winter. Our observations show the diurnal pattern of

  10. Concentrations and Sources of Airborne Particles in a Neonatal Intensive Care Unit

    Science.gov (United States)

    Licina, Dusan; Bhangar, Seema; Brooks, Brandon; Baker, Robyn; Firek, Brian; Tang, Xiaochen; Morowitz, Michael J.; Banfield, Jillian F.; Nazaroff, William W.

    2016-01-01

    Premature infants in neonatal intensive care units (NICUs) have underdeveloped immune systems, making them susceptible to adverse health consequences from air pollutant exposure. Little is known about the sources of indoor airborne particles that contribute to the exposure of premature infants in the NICU environment. In this study, we monitored the spatial and temporal variations of airborne particulate matter concentrations along with other indoor environmental parameters and human occupancy. The experiments were conducted over one year in a private-style NICU. The NICU was served by a central heating, ventilation and air-conditioning (HVAC) system equipped with an economizer and a high-efficiency particle filtration system. The following parameters were measured continuously during weekdays with 1-min resolution: particles larger than 0.3 μm resolved into 6 size groups, CO2 level, dry-bulb temperature and relative humidity, and presence or absence of occupants. Altogether, over sixteen periods of a few weeks each, measurements were conducted in rooms occupied with premature infants. In parallel, a second monitoring station was operated in a nearby hallway or at the local nurses’ station. The monitoring data suggest a strong link between indoor particle concentrations and human occupancy. Detected particle peaks from occupancy were clearly discernible among larger particles and imperceptible for submicron (0.3–1 μm) particles. The mean indoor particle mass concentrations averaged across the size range 0.3–10 μm during occupied periods was 1.9 μg/m3, approximately 2.5 times the concentration during unoccupied periods (0.8 μg/m3). Contributions of within-room emissions to total PM10 mass in the baby rooms averaged 37–81%. Near-room indoor emissions and outdoor sources contributed 18–59% and 1–5%, respectively. Airborne particle levels in the size range 1–10 μm showed strong dependence on human activities, indicating the importance of indoor

  11. Concentrations and Sources of Airborne Particles in a Neonatal Intensive Care Unit.

    Directory of Open Access Journals (Sweden)

    Dusan Licina

    Full Text Available Premature infants in neonatal intensive care units (NICUs have underdeveloped immune systems, making them susceptible to adverse health consequences from air pollutant exposure. Little is known about the sources of indoor airborne particles that contribute to the exposure of premature infants in the NICU environment. In this study, we monitored the spatial and temporal variations of airborne particulate matter concentrations along with other indoor environmental parameters and human occupancy. The experiments were conducted over one year in a private-style NICU. The NICU was served by a central heating, ventilation and air-conditioning (HVAC system equipped with an economizer and a high-efficiency particle filtration system. The following parameters were measured continuously during weekdays with 1-min resolution: particles larger than 0.3 μm resolved into 6 size groups, CO2 level, dry-bulb temperature and relative humidity, and presence or absence of occupants. Altogether, over sixteen periods of a few weeks each, measurements were conducted in rooms occupied with premature infants. In parallel, a second monitoring station was operated in a nearby hallway or at the local nurses' station. The monitoring data suggest a strong link between indoor particle concentrations and human occupancy. Detected particle peaks from occupancy were clearly discernible among larger particles and imperceptible for submicron (0.3-1 μm particles. The mean indoor particle mass concentrations averaged across the size range 0.3-10 μm during occupied periods was 1.9 μg/m3, approximately 2.5 times the concentration during unoccupied periods (0.8 μg/m3. Contributions of within-room emissions to total PM10 mass in the baby rooms averaged 37-81%. Near-room indoor emissions and outdoor sources contributed 18-59% and 1-5%, respectively. Airborne particle levels in the size range 1-10 μm showed strong dependence on human activities, indicating the importance of indoor

  12. Integrated geophysical investigations for the delineation of source and subsurface structure associated with hydro-uranium anomaly: A case study from South Purulia Shear Zone (SPSZ), India

    Science.gov (United States)

    Sharma, S. P.; Biswas, A.

    2012-12-01

    South Purulia Shear Zone (SPSZ) is an important region for prospecting of uranium mineralization. Geological studies and hydro-uranium anomaly suggest the presence of Uranium deposit around Raghunathpur village which lies about 8 km north of SPSZ. However, detailed geophysical investigations have not been carried out in this region for investigation of uranium mineralization. Since surface signature of uranium mineralization is not depicted near the location, a deeper subsurface source is expected for hydro uranium anomaly. To delineate the subsurface structure and to investigate the origin of hydro-uranium anomaly present in the area, Vertical Electrical Sounding (VES) using Schlumberger array and Gradient Resistivity Profiling (GRP) were performed at different locations along a profile perpendicular to the South Purulia Shear Zone. Apparent resistivity computed from the measured sounding data at various locations shows a continuously increasing trend. As a result, conventional apparent resistivity data is not able to detect the possible source of hydro uranium anomaly. An innovative approach is applied which depicts the apparent conductivity in the subsurface revealed a possible connection from SPSZ to Raghunathpur. On the other hand resistivity profiling data suggests a low resistive zone which is also characterized by low Self-Potential (SP) anomaly zone. Since SPSZ is characterized by the source of uranium mineralization; hydro-uranium anomaly at Raghunathpur is connected with the SPSZ. The conducting zone has been delineated from SPSZ to Raghunathpur at deeper depths which could be uranium bearing. Since the location is also characterized by a low gravity and high magnetic anomaly zone, this conducting zone is likely to be mineralized zone. Keywords: Apparent resistivity; apparent conductivity; Self Potential; Uranium mineralization; shear zone; hydro-uranium anomaly.

  13. Hydrogeology, chemical characteristics, and water sources and pathways in the zone of contribution of a public-supply well in San Antonio, Texas

    Science.gov (United States)

    Musgrove, MaryLynn; Fahlquist, Lynne; Stanton, Gregory P.; Houston, Natalie A.; Lindgren, Richard J.

    2011-01-01

    depths and under three different pumping conditions. Additionally, selected monitoring wells and one of the well-field PSWs were sampled several times in response to a rainfall and recharge event to assess short-term (event-scale) temporal variations in water quality. For comparison purposes, groundwater samples were categorized as being from regional aquifer PSWs, from the well field (wellhead samples), from the monitoring wells (excluding the overburden well), from the overburden well, from the PSW depth-dependent sampling, and from temporal sampling. Groundwater samples were analyzed for inorganic, organic, isotopic, and age-dating tracers to characterize geochemical conditions in the aquifer and provide understanding of the mechanisms of mobilization and movement of selected constituents from source areas to a PSW. Sources, tracers, and conditions used to assess water quality and processes affecting the PSW and the aquifer system included (1) carbonate host rock composition; (2) physicochemical constituents; (3) major and trace element concentrations; (4) saturation indices with respect to minerals in aquifer rocks; (5) elemental ratios, such as magnesium to calcium ratios, that are indicative of water-rock interaction processes; (6) oxidation-reduction conditions; (7) nutrient concentrations, in particular nitrate concentrations; (8) the isotopic composition of nitrate, which can point to specific nitrate sources; (9) strontium isotopes; (10) stable isotopes of hydrogen and oxygen; (11) organic contaminant concentrations, including pesticides and volatile organic compounds; (12) age tracers, apparent-age distribution, and dissolved gas data used in age interpretations; (13) depth-dependent water chemistry collected from the PSW under different pumping conditions to assess zones of contribution; and (14) temporal variability in groundwater composition from the PSW and selected monitoring wells in response to an aquifer recharge event. Geochemical results indicate

  14. Lead distribution and possible sources along vertical zone spectrum of typical ecosystems in the Gongga Mountain, eastern Tibetan Plateau

    Science.gov (United States)

    Luo, Ji; Tang, Ronggui; Sun, Shouqin; Yang, Dandan; She, Jia; Yang, Peijun

    2015-08-01

    A total of 383 samples from soil, plant, litterfall and precipitation in four typical ecosystems of Gongga Mountain were collected. Pb concentrations of samples were measured and analyzed. The results showed mean Pb concentrations in different soil layers were in the order of O > A > C, and mean Pb concentrations of the aboveground parts of plant was 3.60 ± 2.54 mg kg-1, with the minimum value of 0.77 mg kg-1 and the maximum value of 10.90 mg kg-1. Pb concentrations in soil's O-horizon and A-horizon showed a downward trend with increasing elevation (the determination coefficient R2 was 0.9478, 0.7918 and 0.9759 respectively). In contrast to other soil layers, the level of Pb concentrations in O-horizon (incomplete decomposition) was significantly high. Litterfall decomposition, atmospheric deposition and the unique climate could be main factors leading high Pb accumulation in soil's O-horizon. What's more, significant correlation (R2 = 0.8126, P soil's A-horizon confirms that fine roots could adsorb and accumulate Pb materials in soil. In general, the fact that Pb inputted into the typical ecosystems in the Gongga Mountain via long-range transportation and deposition of the atmosphere from external Pb sources could be confirmed by the HYSPLIT model and the ratio of CPb/CAl in plants (leaves) and CPb/CAl in litterfall. The mining activities and increasing anthropogenic activities (tourism development) could be main sources of Pb in this area. In order to better understand Pb sources and eco-risks of these typical ecosystems, litterfall decomposition characteristics, biomass of productivity of forest ecosystem, Pb isotopic tracing among air mass, twigs, leaves, litterfall and O-horizon soil in this vertical belt should also be taken into consideration.

  15. Reduction of PM emissions from specific sources reflected on key components concentrations of ambient PM10

    Science.gov (United States)

    Minguillon, M. C.; Querol, X.; Monfort, E.; Alastuey, A.; Escrig, A.; Celades, I.; Miro, J. V.

    2009-04-01

    The relationship between specific particulate emission control and ambient levels of some PM10 components (Zn, As, Pb, Cs, Tl) was evaluated. To this end, the industrial area of Castellón (Eastern Spain) was selected, where around 40% of the EU glazed ceramic tiles and a high proportion of EU ceramic frits (middle product for the manufacture of ceramic glaze) are produced. The PM10 emissions from the ceramic processes were calculated over the period 2000 to 2007 taking into account the degree of implementation of corrective measures throughout the study period. Abatement systems (mainly bag filters) were implemented in the majority of the fusion kilns for frit manufacture in the area as a result of the application of the Directive 1996/61/CE, leading to a marked decrease in PM10 emissions. On the other hand, ambient PM10 sampling was carried out from April 2002 to July 2008 at three urban sites and one suburban site of the area and a complete chemical analysis was made for about 35 % of the collected samples, by means of different techniques (ICP-AES, ICP-MS, Ion Chromatography, selective electrode and elemental analyser). The series of chemical composition of PM10 allowed us to apply a source contribution model (Principal Component Analysis), followed by a multilinear regression analysis, so that PM10 sources were identified and their contribution to bulk ambient PM10 was quantified on a daily basis, as well as the contribution to bulk ambient concentrations of the identified key components (Zn, As, Pb, Cs, Tl). The contribution of the sources identified as the manufacture and use of ceramic glaze components, including the manufacture of ceramic frits, accounted for more than 65, 75, 58, 53, and 53% of ambient Zn, As, Pb, Cs and Tl levels, respectively (with the exception of Tl contribution at one of the sites). The important emission reductions of these sources during the study period had an impact on ambient key components levels, such that there was a high

  16. Disinfection byproduct formation in reverse-osmosis concentrated and lyophilized natural organic matter from a drinking water source.

    Science.gov (United States)

    Pressman, Jonathan G; McCurry, Daniel L; Parvez, Shahid; Rice, Glenn E; Teuschler, Linda K; Miltner, Richard J; Speth, Thomas F

    2012-10-15

    Drinking water treatment and disinfection byproduct (DBP) research can be complicated by natural organic matter (NOM) temporal variability. NOM preservation by lyophilization (freeze-drying) has been long practiced to address this issue; however, its applicability for drinking water research has been limited because the selected NOM sources are atypical of most drinking water sources. The purpose of this research was to demonstrate that reconstituted NOM from a lyophilized reverse-osmosis (RO) concentrate of a typical drinking water source closely represents DBP formation in the original NOM. A preliminary experiment assessed DBP formation kinetics and yields in concentrated NOM, which demonstrated that chlorine decays faster in concentrate, in some cases leading to altered DBP speciation. Potential changes in NOM reactivity caused by lyophilization were evaluated by chlorination of lyophilized and reconstituted NOM, its parent RO concentrate, and the source water. Bromide lost during RO concentration was replaced by adding potassium bromide prior to chlorination. Although total measured DBP formation tended to decrease slightly and unidentified halogenated organic formation tended to increase slightly as a result of RO concentration, the changes associated with lyophilization were minor. In lyophilized NOM reconstituted back to source water TOC levels and then chlorinated, the concentrations of 19 of 21 measured DBPs, constituting 96% of the total identified DBP mass, were statistically indistinguishable from those in the chlorinated source water. Furthermore, the concentrations of 16 of 21 DBPs in lyophilized NOM reconstituted back to the RO concentrate TOC levels, constituting 86% DBP mass, were statistically indistinguishable from those in the RO concentrate. This study suggests that lyophilization can be used to preserve concentrated NOM without substantially altering the precursors to DBP formation. Published by Elsevier Ltd.

  17. Radioactivity in papers: the concentration and source of naturally occurring radionuclides

    International Nuclear Information System (INIS)

    Kobashi, Asaya

    2005-01-01

    The radioactivities of naturally occurring radionuclides ( 226 Ra, 228 Ra, 228 Th and 40 K) in papers such as magazines, newspapers, and copying papers produced in Japan were determined by gamma-ray spectrometry to obtain information on radioactivity level of papers. The X-ray diffraction measurement of the samples was also carried out to elucidate the source of radionuclides contained in them. The average 226 Ra, 228 Ra, 228 Th, and 40 K contents of pocket-sized books were 6.4, 21.5, 23.7, and 18.8 Bq kg -1 , respectively, and those of other kinds of samples were near to or less than the values. The 228 Th content was generally somewhat higher than the 228 Ra content. Possibly 228 Ra was leached from the raw materials of the papers to water during their production in preference to 228 Th. The concentrations of the naturally occurring radionuclides were correlated to each other. The X-ray diffraction study showed that kaolinite, talc, and calcite were contained in the papers. The kaolinite content of the samples was correlated to the concentrations of the naturally occurring radionuclides, indicating that the naturally occurring radionuclides in the paper samples were mainly brought with kaolinite used as filler or coating pigment in the papers. The regression analysis of the data showed that the natural radioactivity content of filler kaolinite was higher than that of pigment kaolinite. (author)

  18. Coastal Zone Color Scanner (CZCS): Imagery of near-surface phytoplankton pigment concentrations from the first coastal ocean dynamics experiment (CODE-1), March - July 1981

    Science.gov (United States)

    Abbott, M. R.; Zion, P. M.

    1984-01-01

    As part of the first Coastal Ocean Dynamics Experiment, images of ocean color were collected from late March until late July, 1981, by the Coastal Zone Color Scanner aboard Nimbus-7. Images that had sufficient cloud-free area to be of interest were processed to yield near-surface phytoplankton pigment concentrations. These images were then remapped to a fixed equal-area grid. This report contains photographs of the digital images and a brief description of the processing methods.

  19. Possible source term of high concentrations of mecoprop-p in leachate and water quality: impact of climate change, public use and disposal.

    Science.gov (United States)

    Idowu, I A; Alkhaddar, R M; Atherton, W

    2014-08-01

    Mecoprop-p herbicide is often found in wells and water abstractions in many areas around Europe, the UK inclusive. There is a growing environmental and public health concern about mecoprop-p herbicide pollution in ground and surface water in England. Reviews suggest that extensive work has been carried out on the contribution of mecoprop-p herbicides from agricultural use whilst more work needs to be carried out on the contribution of mecoprop-p herbicide from non-agricultural use. The study covers two landfill sites in Weaver/Gowy Catchment. Mecoprop-p herbicide concentrations in the leachate quality range between 0.06 and 290 microg l1 in cells. High concentration ofmecoprop-p herbicide in the leachate quality suggests that there is a possible source term in the waste stream. This paper addresses the gap by exploring possible source terms of mecoprop-p herbicide contamination on landfill sites and evaluates the impact of public purchase, use and disposal alongside climate change on seasonal variations in mecoprop-p concentrations. Mecoprop-p herbicide was found to exceed the EU drinking water quality standards at the unsaturated zone/aquifer with observed average concentrations ranging between 0.005 and 7.96 microg l1. A route map for mecoprop-p herbicide source term contamination is essential for mitigation and pollution management with emphasis on both consumer and producer responsibility towards use of mecoprop-p product. In addition, improvement in data collection on mecoprop-p concentrations and detailed seasonal herbicide sales for non-agricultural purposes are needed to inform the analysis and decision process.

  20. A SUMMARY OF TOTAL MERCURY CONCENTRATIONS IN FLORA AND FAUNA NEAR CONTAMINANT SOURCES IN THE GULF OF MEXICO

    Science.gov (United States)

    This report summarizes total mercury concentrations for environmental media collected from near-coastal areas including those impacted by contaminant sources common to the Gulf of Mexico. Water, sediment, fish, blue crabs, oysters, clams, mussels, periphyton and seagrasses were ...

  1. Concentrations, loads, and sources of polychlorinated biphenyls, Neponset River and Neponset River Estuary, eastern Massachusetts

    Science.gov (United States)

    Breault, Robert F.

    2011-01-01

    Walter Baker Impoundments were 3,490 and 2,450 ng/g wet wt (filleted) and 6,890 and 4,080 ng/g wet wt (whole fish). Total PCB-congener concentrations measured in the whole bodies of estuarine bait fish (common mummichog) averaged 708 ng/g wet wt. PCBs that pass from the Neponset River to the Neponset River Estuary are either dissolved or associated with particulate matter (including living and nonliving material) suspended in the water column. A small proportion of PCBs may also be transported as part of the body burden of fish and wildlife. During the period May 13, 2005 to April 28, 2006, about 5,100 g (3.8 L or 1 gal) of PCBs were transported from the Neponset River to the Neponset River Estuary. Generally, about one-half of these PCBs were dissolved in the water column and the other half were associated with particulate matter; however, the proportion that was either dissolved or particulate varied seasonally. Most PCBs transported from the river to the estuary are composed of four or fewer chlorine atoms per biphenyl molecule. The data suggest that widespread PCB contamination of the lower Neponset River originated from Mother Brook, a Neponset River tributary, starting sometime around the early 1950s or earlier. In 1955, catastrophic dam failure caused by flooding likely released PCB-contaminated sediment downstream and into the Neponset River Estuary. PCBs from this source area likely continued to be released after the flood and during subsequent rebuilding of downstream dams. Today (2007), PCBs are mostly trapped behind these dams; however, some PCBs either diffuse or are entrained back into the water column and are transported downstream by river water into the estuary or volatilize into the atmosphere. In addition to the continuing release of PCBs from historically contaminated bottom sediment, PCBs are still (2007) originating from source areas along Mother and Meadow Brook as well as other sources along the river and Boston Harbor. PCBs from the river

  2. Trace elements in particulate matter from metropolitan regions of Northern China: Sources, concentrations and size distributions.

    Science.gov (United States)

    Pan, Yuepeng; Tian, Shili; Li, Xingru; Sun, Ying; Li, Yi; Wentworth, Gregory R; Wang, Yuesi

    2015-12-15

    Public concerns over airborne trace elements (TEs) in metropolitan areas are increasing, but long-term and multi-site observations of size-resolved aerosol TEs in China are still lacking. Here, we identify highly elevated levels of atmospheric TEs in megacities and industrial sites in a Beijing-Tianjin-Hebei urban agglomeration relative to background areas, with the annual mean values of As, Pb, Ni, Cd and Mn exceeding the acceptable limits of the World Health Organization. Despite the spatial variability in concentrations, the size distribution pattern of each trace element was quite similar across the region. Crustal elements of Al and Fe were mainly found in coarse particles (2.1-9 μm), whereas the main fraction of toxic metals, such as Cu, Zn, As, Se, Cd and Pb, was found in submicron particles (metals were enriched by over 100-fold relative to the Earth's crust. The size distributions of Na, Mg, K, Ca, V, Cr, Mn, Ni, Mo and Ba were bimodal, with two peaks at 0.43-0.65 μm and 4.7-5.8 μm. The combination of the size distribution information, principal component analysis and air mass back trajectory model offered a robust technique for distinguishing the main sources for airborne TEs, e.g., soil dust, fossil fuel combustion and industrial emissions, at different sites. In addition, higher elemental concentrations coincided with westerly flow, indicating that polluted soil and fugitive dust were major sources of TEs on the regional scale. However, the contribution of coal burning, iron industry/oil combustion and non-ferrous smelters to atmospheric metal pollution in Northern China should be given more attention. Considering that the concentrations of heavy metals associated with fine particles in the target region were significantly higher than those in other Asian sites, the implementations of strict environmental standards in China are required to reduce the amounts of these hazardous pollutants released into the atmosphere. Copyright © 2015 Elsevier B

  3. Geologic sources and concentrations of selenium in the West-Central Denver Basin, including the Toll Gate Creek watershed, Aurora, Colorado, 2003-2007

    Science.gov (United States)

    Paschke, Suzanne S.; Walton-Day, Katherine; Beck, Jennifer A.; Webbers, Ank; Dupree, Jean A.

    2014-01-01

    Toll Gate Creek, in the west-central part of the Denver Basin, is a perennial stream in which concentrations of dissolved selenium have consistently exceeded the Colorado aquatic-life standard of 4.6 micrograms per liter. Recent studies of selenium in Toll Gate Creek identified the Denver lignite zone of the non-marine Cretaceous to Tertiary-aged (Paleocene) Denver Formation underlying the watershed as the geologic source of dissolved selenium to shallow ground-water and surface water. Previous work led to this study by the U.S. Geological Survey, in cooperation with the City of Aurora Utilities Department, which investigated geologic sources of selenium and selenium concentrations in the watershed. This report documents the occurrence of selenium-bearing rocks and groundwater within the Cretaceous- to Tertiary-aged Denver Formation in the west-central part of the Denver Basin, including the Toll Gate Creek watershed. The report presents background information on geochemical processes controlling selenium concentrations in the aquatic environment and possible geologic sources of selenium; the hydrogeologic setting of the watershed; selenium results from groundwater-sampling programs; and chemical analyses of solids samples as evidence that weathering of the Denver Formation is a geologic source of selenium to groundwater and surface water in the west-central part of the Denver Basin, including Toll Gate Creek. Analyses of water samples collected from 61 water-table wells in 2003 and from 19 water-table wells in 2007 indicate dissolved selenium concentrations in groundwater in the west-central Denver Basin frequently exceeded the Colorado aquatic-life standard and in some locations exceeded the primary drinking-water standard of 50 micrograms per liter. The greatest selenium concentrations were associated with oxidized groundwater samples from wells completed in bedrock materials. Selenium analysis of geologic core samples indicates that total selenium

  4. Source characteristics of moderate size events using empirical Green funclions: an application to some Guerrero (Mexico subduction zone earthquakes

    Directory of Open Access Journals (Sweden)

    S. K. Singh

    1994-06-01

    Full Text Available The records of an aftershock (M ~ 4 of a moderate size event (M = 5.9 which occurred along the subduction zone of Guerrero (Mexico, are used as empirical Green functions (EGF to determine the source characteristics of the mainshock and of its smaller size (M = 5.5 foreshock. The data consist of accelerograms recorded by the Guerrero Accelerograph Array, a high dynamic range strong motion array. The three events appear to be located close to each other at distances much smaller than the source to receiver distances. The fault mechanism of the mainshock is computed by non-linear inversion of P polarity readings and S wave polarizations determined at two near source stations. The foreshock and aftershock fault mechanisms are similar to that of the mainshock as inferred from long period data and shear wave polarization analysis. The maximum likelihood solution is well constrained, indicating a typical shallow dipping thrust fault mechanism, with the P-axis approximately oriented in a SSW direction. The source time functions (STFs of the mainshock and foreshock events are determined using a new method of deconvolution of the EGF records at three strong motion sites. In this method the STF of the large event is approximated by a superposition of pseudo triangular pulses whose parameters are determined by a non-linear inversion in frequency domain. The source time function of the mainshock shows the presence of two separate pulses, which can be related to multiple rupture episodes. The relative location of mainshock sub-events is done by using plots of isochrones computed from measurementes of the time delay between pulses on the STF records at each station. The first sub-event is located no more than 2.5-3 km away from the other along the fault strike. The STF retrieved from foreshock records shows single pulse waveforms. The computed STFs are used to estimate seismic moments, source radii and stress release of the events assuming a circular fault

  5. Modeling non-point source pollutants in the vadose zone: Back to the basics

    Science.gov (United States)

    Corwin, Dennis L.; Letey, John, Jr.; Carrillo, Marcia L. K.

    More than ever before in the history of scientific investigation, modeling is viewed as a fundamental component of the scientific method because of the relatively recent development of the computer. No longer must the scientific investigator be confined to artificially isolated studies of individual processes that can lead to oversimplified and sometimes erroneous conceptions of larger phenomena. Computer models now enable scientists to attack problems related to open systems such as climatic change, and the assessment of environmental impacts, where the whole of the interactive processes are greater than the sum of their isolated components. Environmental assessment involves the determination of change of some constituent over time. This change can be measured in real time or predicted with a model. The advantage of prediction, like preventative medicine, is that it can be used to alter the occurrence of potentially detrimental conditions before they are manifest. The much greater efficiency of preventative, rather than remedial, efforts strongly justifies the need for an ability to accurately model environmental contaminants such as non-point source (NPS) pollutants. However, the environmental modeling advances that have accompanied computer technological development are a mixed blessing. Where once we had a plethora of discordant data without a holistic theory, now the pendulum has swung so that we suffer from a growing stockpile of models of which a significant number have never been confirmed or even attempts made to confirm them. Modeling has become an end in itself rather than a means because of limited research funding, the high cost of field studies, limitations in time and patience, difficulty in cooperative research and pressure to publish papers as quickly as possible. Modeling and experimentation should be ongoing processes that reciprocally enhance one another with sound, comprehensive experiments serving as the building blocks of models and models

  6. Effect of Roughage Source and Roughage to Concentrate Ratio on Animal Performance and Rumen Development in Veal Calves

    NARCIS (Netherlands)

    Suárez, B.J.; Reenen, van C.G.; Stockhofe, N.; Dijkstra, J.; Gerrits, W.J.J.

    2007-01-01

    Sixty-four male Holstein-Friesian x Dutch Friesian veal calves (46 ± 3.0 kg) were used to evaluate the effect of the inclusion of different levels and sources of dietary roughage on animal performance and rumen development. Treatments consisted of 1) C100 = concentrate only; 2) C70-S30 = concentrate

  7. Organic matter compounds as source indicators and tracers for marine pollution in a western Mediterranean coastal zone.

    Science.gov (United States)

    Amorri, Jalila; Geffroy-Rodier, Claude; Boufahja, Fehmi; Mahmoudi, Ezzeddine; Aïssa, Patricia; Ksibi, Mohamed; Amblès, André

    2011-11-01

    Complex organic compounds found in oil and sediments linked with a particular source (such as algae, bacteria or vascular plants) are defined as biomarkers and are useful dating indicators in organic geochemistry. This paper presents the composition of the organic matter (OM) on marine surface sediments from a degraded Tunisian coast analysed by pyrolysis and gas chromatography-mass spectrometry (GC-MS). High total OM contents (0.3-4.2%) were detected with high levels of saturated linear hydrocarbons. The aliphatic lipids had contributed with up to 11.7% of the total OM, and their distribution had consisted of resolved compounds (n-alkanes and fatty acid (FAs)) and an unresolved complex mixture. Hydrocarbons, primarily n-alkanes, were ranged from 368 to 3,886 μg g(-1). The FAs (674-2,568 μg g(-1)) were dominated by derived primary production, and the short chain FAs (C16 and C18) were the most abundant throughout. The ubiquitous presence of petroleum contamination, mainly from offshore oil exploration, discharge of pollutants from rivers, shipping activities and atmospheric deposition was found in all samples. The Gabès littoral seems to be quite to very polluted near the industrial zone of Ghannouch. The C/H ratio (generally around 5.9), the thermal analysis and GC-MS of n-alkanes and FAs showed that the OM in the studied area was composed of anthropogenic/petrogenic, marine and continental sources. Our study represents an innovative approach to assessing environmental pollution. The evaluation of organic matter by examination of sterols, alkanes and fatty acids allows the identification of source, both anthropogenic and natural.

  8. Concentration levels and source apportionment of ultrafine particles in road microenvironments

    Science.gov (United States)

    Argyropoulos, G.; Samara, C.; Voutsa, D.; Kouras, A.; Manoli, E.; Voliotis, A.; Tsakis, A.; Chasapidis, L.; Konstandopoulos, A.; Eleftheriadis, K.

    2016-03-01

    A mobile laboratory unit (MOBILAB) with on-board instrumentation (Scanning Mobility Particle Sizer, SMPS; Ambient NOx analyzer) was used to measure size-resolved particle number concentrations (PNCs) of quasi-ultrafine particles (UFPs, 9-372 nm), along with NOx, in road microenvironments. On-road measurements were carried out in and around a large Greek urban agglomeration, the Thessaloniki Metropolitan Area (TMA). Two 2-week measurement campaigns were conducted during the warm period of 2011 and the cold period of 2012. During each sampling campaign, MOBILAB was driven through a 5-day inner-city route and a second 5-day external route covering in total a wide range of districts (urban, urban background, industrial and residential), and road types (major and minor urban roads, freeways, arterial and interurban roads). All routes were conducted during working days, in morning and in afternoon hours under real-world traffic conditions. Spatial classification of MOBILAB measurements involved the assignment of measurement points to location bins defined by the aspect ratio of adjacent urban street canyons (USCs). Source apportionment was further carried out, by applying Positive Matrix Factorization (PMF) to particle size distribution data. Apportioned PMF factors were interpreted, by employing a two-step methodology, which involved (a) statistical association of PMF factor contributions with 12 h air-mass back-trajectories ending at the TMA during MOBILAB measurements, and (b) Multiple Linear Regression (MLR) using PMF factor contributions as the dependent variables, while relative humidity, solar radiation flux, and vehicle speed were used as the independent variables. The applied data analysis showed that low-speed cruise and high-load engine operation modes are the two dominant sources of UFPs in most of the road microenvironments in the TMA, with significant contributions from background photochemical processes during the warm period, explaining the reversed

  9. Source tracking swine fecal waste in surface water proximal to swine concentrated animal feeding operations.

    Science.gov (United States)

    Heaney, Christopher D; Myers, Kevin; Wing, Steve; Hall, Devon; Baron, Dothula; Stewart, Jill R

    2015-04-01

    Swine farming has gone through many changes in the last few decades, resulting in operations with a high animal density known as confined animal feeding operations (CAFOs). These operations produce a large quantity of fecal waste whose environmental impacts are not well understood. The purpose of this study was to investigate microbial water quality in surface waters proximal to swine CAFOs including microbial source tracking of fecal microbes specific to swine. For one year, surface water samples at up- and downstream sites proximal to swine CAFO lagoon waste land application sites were tested for fecal indicator bacteria (fecal coliforms, Escherichia coli and Enterococcus) and candidate swine-specific microbial source-tracking (MST) markers (Bacteroidales Pig-1-Bac, Pig-2-Bac, and Pig-Bac-2, and methanogen P23-2). Testing of 187 samples showed high fecal indicator bacteria concentrations at both up- and downstream sites. Overall, 40%, 23%, and 61% of samples exceeded state and federal recreational water quality guidelines for fecal coliforms, E. coli, and Enterococcus, respectively. Pig-1-Bac and Pig-2-Bac showed the highest specificity to swine fecal wastes and were 2.47 (95% confidence interval [CI]=1.03, 5.94) and 2.30 times (95% CI=0.90, 5.88) as prevalent proximal down- than proximal upstream of swine CAFOs, respectively. Pig-1-Bac and Pig-2-Bac were also 2.87 (95% CI=1.21, 6.80) and 3.36 (95% CI=1.34, 8.41) times as prevalent when 48 hour antecedent rainfall was greater than versus less than the mean, respectively. Results suggest diffuse and overall poor sanitary quality of surface waters where swine CAFO density is high. Pig-1-Bac and Pig-2-Bac are useful for tracking off-site conveyance of swine fecal wastes into surface waters proximal to and downstream of swine CAFOs and during rain events. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Impact of Front Range sources on reactive nitrogen concentrations and deposition in Rocky Mountain National Park

    Directory of Open Access Journals (Sweden)

    Katherine B. Benedict

    2018-05-01

    Full Text Available Human influenced atmospheric reactive nitrogen (RN is impacting ecosystems in Rocky Mountain National Park (ROMO. Due to ROMO’s protected status as a Class 1 area, these changes are concerning, and improving our understanding of the contributions of different types of RN and their sources is important for reducing impacts in ROMO. In July–August 2014 the most comprehensive measurements (to date of RN were made in ROMO during the Front Range Air Pollution and Photochemistry Éxperiment (FRAPPÉ. Measurements included peroxyacetyl nitrate (PAN, C1–C5 alkyl nitrates, and high-time resolution NOx, NOy, and ammonia. A limited set of measurements was extended through October. Co-located measurements of a suite of volatile organic compounds provide information on source types impacting ROMO. Specifically, we use ethane as a tracer of oil and gas operations and tetrachloroethylene (C2Cl4 as an urban tracer to investigate their relationship with RN species and transport patterns. Results of this analysis suggest elevated RN concentrations are associated with emissions from oil and gas operations, which are frequently co-located with agricultural production and livestock feeding areas in the region, and from urban areas. There also are periods where RN at ROMO is impacted by long-range transport. We present an atmospheric RN budget and a nitrogen deposition budget with dry and wet components. Total deposition for the period (7/1–9/30 was estimated at 1.58 kg N/ha, with 87% from wet deposition during this period of above average precipitation. Ammonium wet deposition was the dominant contributor to total nitrogen deposition followed by nitrate wet deposition and total dry deposition. Ammonia was estimated to be the largest contributor to dry deposition followed by nitric acid and PAN (other species included alkyl nitrates, ammonium and nitrate. All three species are challenging to measure routinely, especially at high time resolution.

  11. Toward Synchronous Evaluation of Source Apportionments for Atmospheric Concentration and Deposition of Sulfate Aerosol Over East Asia

    Science.gov (United States)

    Itahashi, S.

    2018-03-01

    Source apportionments for atmospheric concentration, dry deposition, and wet deposition of sulfate aerosol (SO42-) were synchronously evaluated over East Asia, a main source of anthropogenic sulfur dioxide (SO2) emissions. Estimating dry deposition was difficult owing to the difficulty of measuring deposition velocity directly; therefore, sensitivity simulations using two dry deposition schemes were conducted. Moreover, sensitivity simulations for different emission inventories, the largest uncertainty source in the air quality model, were also conducted. In total, four experimental settings were used. Model performance was verified for atmospheric concentration and wet deposition using a ground-based observation network in China, Korea, and Japan, and all four model settings captured the observations. The underestimation of wet deposition over China was improved by an adjusted approach that linearly scaled the modeled precipitation values to observations. The synchronous evaluation of source apportionments for atmospheric concentration and dry and wet deposition showed the dominant contribution of anthropogenic emissions from China to the atmospheric concentration and deposition in Japan. The contributions of emissions from volcanoes were more important for wet deposition than for atmospheric concentration. Differences in the dry deposition scheme and emission inventory did not substantially influence the relative ratio of source apportionments over Japan. Because the dry deposition was more attributed to local factors, the differences in dry deposition may be an important determinant of the source contributions from China to Japan. Verification of these findings, including the dry deposition velocity, is necessary for better understanding of the behavior of sulfur compound in East Asia.

  12. The adsorption/desorption of phosphorus in freshwater sediments from buffer zones: the effects of sediment concentration and pH.

    Science.gov (United States)

    Zhang, Liang; Du, Yun; Du, Chao; Xu, Meng; Loáiciga, Hugo A

    2016-01-01

    Riparian buffer zones adjacent to reservoirs and lakes protect aquatic ecosystems from polluted surface runoff. Sediments, collected from the buffer zones of Danjiangkou Reservoir (SR) and Honghu Lake (SL) in an ecologically fragile region in central China, were evaluated to reveal their phosphorus-adsorbing/desorbing properties and storage capacities. A nonlinear regression method was used to fit the pseudo-second-order kinetic and the modified crossover-type Langmuir isotherm models to the experimental data. It is shown that the adsorption of phosphorus onto the studied sediments followed the pseudo-second-order kinetic expression. The modified crossover-type Langmuir isotherm model was found to be a suitable method for describing adsorption/desorption processes in the experimental sediments. The maximum adsorption capacities (Q m), partitioning coefficients (K p), native adsorbed exchangeable phosphorus (NAP), and equilibrium phosphorus concentration (EPC0) were subsequently obtained for the experimental sediments. The effects of sediment concentration and pH were also investigated by batch experiments and Fourier transformation infrared and scanning electron microscopy analyses. The adsorption/desorption characteristics of different phosphate species on the sediments from reservoir and lake buffer zones were identified.

  13. Mercury concentration in the sediments as a function of changing climate in coastal zone of Southern Baltic Sea – preliminary results

    Directory of Open Access Journals (Sweden)

    Bełdowska M.

    2013-04-01

    Full Text Available Mercury, despite of its many uses in industry, is also highly toxic. It is highly neurotoxic, and because of the ability of mercury to penetrate placental barrier, in some countries ban on predatory fish consumption (the main route of mercury into human organism by pregnant women was introduced. There are very little publications describing the consequences of weather anomalies on contaminants cycles. No research was published concerning the reemission of Hg due to climate change in the Southern Baltic Sea. The study area was situated in the coastal zone of the Gulf of Gdansk - the Southern Baltic. Samples of different species of macrophytobenthos were collected once a month during 2006-2012. Samples of Potamogeton pectinatus, sediments and pore waters were collected once a month from February 2011 to January 2012. The climate changes in the moderate latitudes: extension of the fall season, has contributed to stabilization of high concentrations of mercury in pore waters. Lack of ice cover in the coastal zone and simultaneous occurrence of storms had an impact on supply of the organic matter to the sediments and the increased concentration of Hg. More intense burning of fossil fuels in this season favored the increased metal concentration in the atmosphere and consequently an increase of the atmospheric deposition of metals to the sediments. This led to a fourfold increase of the mercury concentration in sediments as compared to fall season.

  14. Concentrations, sources and spatial distribution of polycyclic aromatic hydrocarbons in soils from Beijing, Tianjin and surrounding areas, North China

    International Nuclear Information System (INIS)

    Wang Wentao; Massey Simonich, Staci L.; Xue Miao; Zhao Jingyu; Zhang Na; Wang Rong; Cao Jun; Tao Shu

    2010-01-01

    The concentrations, profiles, sources and spatial distribution of polycyclic aromatic hydrocarbons (PAHs) were determined in 40 surface soil samples collected from Beijing, Tianjin and surrounding areas, North China in 2007, and all sampling sites were far from industrial areas, roadsides and other pollution sources, and across a range of soil types in remote, rural villages and urban areas. The total concentrations of 16 PAHs ranged from 31.6 to 1475.0 ng/g, with an arithmetic average of 336.4 ng/g. The highest PAH concentrations were measured in urban soils, followed by rural village soils and soils from remote locations. The remote-rural village-urban PAH concentration gradient was related to population density, gross domestic product (GDP), long-range atmospheric transport and different types of land use. In addition, the PAH concentration was well correlated with the total organic carbon (TOC) concentration of the soil. The PAH profile suggested that coal combustion and biomass burning were primary PAH sources. - The concentration, profiles and possible sources of PAHs in Beijing, Tianjin and surrounding area soils were studied and related to population density and gross domestic product (GDP).

  15. Mercury concentration in vegetables of Pakistan irrigated by different water sources

    International Nuclear Information System (INIS)

    Shaheen, Q.; Mahmood, Z.; Imran, M.

    2011-01-01

    Mercury levels were determined in twenty samples of each vegetable i.e., Spinach (Spinacia oleracea), Lettuce (Lactuca sativa), Carrot (Daucus cariota), Capsicum (Capsicum fistulosus), Sweet pea (Lathyrus Odoratus), Potato (Solanum tuberosum) and Cabbage (Brassica oleracea), with a special reference of source of water of irrigation, i.e., tube well water, canal water and municipal sewage water. All the samples of vegetables were collected during the year 2006, 2007 and 2008 from the five districts of Pakistan viz Lahore, Kasur, Multan, Bahawalpur and R.Y. Khan. Statistical analysis such as Test of significance and multiple comparison were applied on the data obtained. The results showed that the concentration of Mercury in vegetables irrigated by canal water, sewage water and tube well water was in the range of 3.1-88.9 ppb and 9.0-130.6 ppb. It can be concluded from this study that the uptake of mercury by vegetables collected from above five districts of Pakistan was in the following order. Leafy vegetables > Root vegetables > seedy vegetables. (author)

  16. Radon concentration; source strength and ventilation rate: how well do we know the connections

    International Nuclear Information System (INIS)

    Ring, J.W.

    1984-01-01

    The simple steady state model which is frequently used to relate radon concentration (C), source strength (S) and ventilation rate (l/'tau') is expressed in the equation C=S'tau'. The assumptions of this model are given and their validity explored in this paper. In particular the assumption of steady state conditions fot the ventilation rate is studied experimentally in a simple one chamber building, the Solar Classroom at Hamilton College. Even in this simple case variations are found of a factor of three or more in 'tau' which can be attributed to wind and stack effects. Studies of other houses are cited which show that variations of 'tau' between houses can be as large as factor of sixty or more. The implications of these results for developing ventilation standards or for mitigating the indoor radon problem are suggested. Individual houses can be understood and mitigating strategies implemented in them on a case by case basis but a statistical treatment of houses in general does not seem to be a fruitful approach. (Author)

  17. New materials for methane capture from dilute and medium-concentration sources

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J; Maiti, A; Lin, LC; Stolaroff, JK; Smit, B; Aines, RD

    2013-04-16

    Methane (CH4) is an important greenhouse gas, second only to CO2, and is emitted into the atmosphere at different concentrations from a variety of sources. However, unlike CO2, which has a quadrupole moment and can be captured both physically and chemically in a variety of solvents and porous solids, methane is completely non-polar and interacts very weakly with most materials. Thus, methane capture poses a challenge that can only be addressed through extensive material screening and ingenious molecular-level designs. Here we report systematic in silico studies on the methane capture effectiveness of two different materials systems, that is, liquid solvents (including ionic liquids) and nanoporous zeolites. Although none of the liquid solvents appears effective as methane sorbents, systematic screening of over 87,000 zeolite structures led to the discovery of a handful of candidates that have sufficient methane sorption capacity as well as appropriate CH4/CO2 and/or CH4/N-2 selectivity to be technologically promising.

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

    Science.gov (United States)

    Harte, Philip T.

    2015-01-01

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

  19. Back-trajectory-based source apportionment of airborne sulfur and nitrogen concentrations at Rocky Mountain National Park, Colorado, USA

    Science.gov (United States)

    Gebhart, Kristi A.; Schichtel, Bret A.; Malm, William C.; Barna, Michael G.; Rodriguez, Marco A.; Collett, Jeffrey L., Jr.

    2011-01-01

    The Rocky Mountain Atmospheric Nitrogen and Sulfur Study (RoMANS), conducted during the spring and summer of 2006, was designed to assess the sources of nitrogen and sulfur species that contribute to wet and dry deposition and visibility impairment at Rocky Mountain National Park (RMNP), Colorado. Several source apportionment methods were utilized for RoMANS, including the Trajectory Mass Balance (TrMB) Model, a receptor-based method in which the hourly measured concentrations are the dependent variables and the residence times of back trajectories in several source regions are the independent variables. The regression coefficients are estimates of the mean emissions, dispersion, chemical transformation, and deposition between the source areas and the receptors. For RoMANS, a new ensemble technique was employed in which input parameters were varied to explore the range, variability, and model sensitivity of source attribution results and statistical measures of model fit over thousands of trials for each set of concentration measurements. Results showed that carefully chosen source regions dramatically improved the ability of TrMB to reproduce temporal patterns in the measured concentrations, and source attribution results were also very sensitive to source region choices. Conversely, attributions were relatively insensitive to trajectory start height, trajectory length, minimum endpoints per source area, and maximum endpoint height, as long as the trajectories were long enough to reach contributing source areas and were not overly restricted in height or horizontal location. Source attribution results estimated that more than half the ammonia and 30-45% of sulfur dioxide and other nitrogen-containing species at the RoMANS core site were from sources within the state of Colorado. Approximately a quarter to a third of the sulfate was from within Colorado.

  20. Effect of sediment composition on methane concentration and production in the transition zone of a mangrove (Sepetiba Bay, Rio de Janeiro, Brazil).

    Science.gov (United States)

    Marinho, C C; Campos, E A; Guimarães, J R D; Esteves, F A

    2012-08-01

    The aim of this research was to evaluate the effect of sediment composition on methane (CH4) dynamics in sediments of different areas in the transition zone between a mangrove and the sea. This research was conducted in a mangrove at Coroa Grande, on the southern coast of Rio de Janeiro. Samples were collected at three stations: (1) region colonised by Rhizophora mangle L. on the edge of the mangrove, (2) region colonised by seagrasses and (3) infra-littoral region without vegetation. Samples were collected from the surface layer of the sediment to determine the concentrations of nutrients (C, N and P) and CH4 concentration and production. We observed that concentrations of CH4 and carbon (C) were significantly higher (p Mangrove Coroa Grande is a function of available OM suggesting a possible inhibition of methanotrophy by intense oxygen consumption in the soil surface covered by detritus of Rhizophora mangle vegetation.

  1. Percutaneous internal fixation of proximal fifth metatarsal jones fractures (Zones II and III) with Charlotte Carolina screw and bone marrow aspirate concentrate: an outcome study in athletes.

    Science.gov (United States)

    Murawski, Christopher D; Kennedy, John G

    2011-06-01

    Internal fixation is a popular first-line treatment method for proximal fifth metatarsal Jones fractures in athletes; however, nonunions and screw breakage can occur, in part because of nonspecific fixation hardware and poor blood supply. To report the results from 26 patients who underwent percutaneous internal fixation with a specialized screw system of a proximal fifth metatarsal Jones fracture (zones II and III) and bone marrow aspirate concentrate. Case series; Level of evidence, 4. Percutaneous internal fixation for a proximal fifth metatarsal Jones fracture (zones II and III) was performed on 26 athletic patients (mean age, 27.47 years; range, 18-47). All patients were competing at some level of sport and were assessed preoperatively and postoperatively using the Foot and Ankle Outcome Score and SF-12 outcome scores. The mean follow-up time was 20.62 months (range, 12-28). Of the 26 fractures, 17 were traditional zone II Jones fractures, and the remaining 9 were zone III proximal diaphyseal fractures. The mean Foot and Ankle Outcome Score significantly increased, from 51.15 points preoperatively (range, 14-69) to 90.91 at final follow-up (range, 71-100; P fracture healing on standard radiographs was 5 weeks after surgery (range, 4-24). Two patients did not return to their previous levels of sporting activity. One patient experienced a delayed union, and 1 healed but later refractured. Percutaneous internal fixation of proximal fifth metatarsal Jones fractures, with a Charlotte Carolina screw and bone marrow aspirate concentrate, provides more predictable results while permitting athletes a return to sport at their previous levels of competition, with few complications.

  2. Exposition by inhalation to the benzene, toluene, ethyl-benzene and xylenes (BTEX) in the air. Sources, measures and concentrations; Exposition par inhalation au benzene, toluene, ethylbenzene et xylenes (BTEX) dans l'air. Source, mesures et concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Del Gratta, F.; Durif, M.; Fagault, Y.; Zdanevitch, I

    2004-12-15

    This document presents the main techniques today available to characterize the benzene, toluene, ethyl-benzene and xylene (BTEX) concentrations in the air for different contexts: urban and rural areas or around industrial installations but also indoor and occupational area. It provides information to guide laboratories and research departments. A synthesis gives also the main emissions sources of these compounds as reference concentrations measured in different environments. (A.L.B.)

  3. Estimation of time averages from irregularly spaced observations - With application to coastal zone color scanner estimates of chlorophyll concentration

    Science.gov (United States)

    Chelton, Dudley B.; Schlax, Michael G.

    1991-01-01

    The sampling error of an arbitrary linear estimate of a time-averaged quantity constructed from a time series of irregularly spaced observations at a fixed located is quantified through a formalism. The method is applied to satellite observations of chlorophyll from the coastal zone color scanner. The two specific linear estimates under consideration are the composite average formed from the simple average of all observations within the averaging period and the optimal estimate formed by minimizing the mean squared error of the temporal average based on all the observations in the time series. The resulting suboptimal estimates are shown to be more accurate than composite averages. Suboptimal estimates are also found to be nearly as accurate as optimal estimates using the correct signal and measurement error variances and correlation functions for realistic ranges of these parameters, which makes it a viable practical alternative to the composite average method generally employed at present.

  4. Integration of Remote Sensing and other public GIS data source to identify suitable zones for groundwater exploitation by manual drilling

    Science.gov (United States)

    Fussi, Fabio; Fava, Francesco; Di Mauro, Biagio; Bonomi, Tullia; Fumagalli, Letizia; DI Leo, Margherita; Hamidou Kane, Cheik; Faye, Gayane; Niang, Magatte; Wade, Souleye; Hamidou, Barry; Colombo, Roberto

    2015-04-01

    In several countries of the world the situation of water supply is still critical, far from the international target defined by United Nations for 2015 (Millenium Development Goals) and producing a huge impact on health and living condition of the population. Manual drilling (it means techniques to drill boreholes for water using human or animal power) is well known and practiced for centuries in many countries. In recent years, it has been considered a potential strategy to increase water access in poor countries and has raised the attention of national governments and international organizations. Manual drilling is applicable only where hydrogeological context is suitable, according to the following conditions: thick layers of unconsolidated sediments and shallow water table. Mapping of zones with suitable hydrogeological context has been carried out in several countries in Africa, but the results have evident limitations; previous methods are based on existing direct data and qualitative experience, leading to unreliable interpretation when direct data are limited. This research aims to develop a methodology to estimate shallow hydrogeological features and asses the distribution of suitable zones for manual drilling through the integration of indirect information obtained from remote sensing and other existing source of data. The research is carried out in two different study areas, in Senegal and Guinea (Western Africa), with semi-arid climate, moderate vegetation cover, unconsolidated sandy and clay deposits overlaying sedimentary and igneous rocks A set of variables have been obtained through processing of three categories of data, listed below: - geology, geomorphology, soil and land cover, obtained from existing thematic maps; - vegetation phenology, apparent thermal inertia, and soil moisture, obtained from analysis of multitemporal optical (MOD13Q1), thermal (MOD11A1), and radar (ASAR) remotely sensed data: -morphometric parameters, obtained from public

  5. Long-term trends in California mobile source emissions and ambient concentrations of black carbon and organic aerosol.

    Science.gov (United States)

    McDonald, Brian C; Goldstein, Allen H; Harley, Robert A

    2015-04-21

    A fuel-based approach is used to assess long-term trends (1970-2010) in mobile source emissions of black carbon (BC) and organic aerosol (OA, including both primary emissions and secondary formation). The main focus of this analysis is the Los Angeles Basin, where a long record of measurements is available to infer trends in ambient concentrations of BC and organic carbon (OC), with OC used here as a proxy for OA. Mobile source emissions and ambient concentrations have decreased similarly, reflecting the importance of on- and off-road engines as sources of BC and OA in urban areas. In 1970, the on-road sector accounted for ∼90% of total mobile source emissions of BC and OA (primary + secondary). Over time, as on-road engine emissions have been controlled, the relative importance of off-road sources has grown. By 2010, off-road engines were estimated to account for 37 ± 20% and 45 ± 16% of total mobile source contributions to BC and OA, respectively, in the Los Angeles area. This study highlights both the success of efforts to control on-road emission sources, and the importance of considering off-road engine and other VOC source contributions when assessing long-term emission and ambient air quality trends.

  6. Vertical profile, source apportionment, and toxicity of PAHs in sediment cores of a wharf near the coal-based steel refining industrial zone in Kaohsiung, Taiwan.

    Science.gov (United States)

    Chen, Chih-Feng; Chen, Chiu-Wen; Ju, Yun-Ru; Dong, Cheng-Di

    2016-03-01

    Three sediment cores were collected from a wharf near a coal-based steel refining industrial zone in Kaohsiung, Taiwan. Analyses for 16 polycyclic aromatic hydrocarbons (PAHs) of the US Environmental Protection Agency priority list in the core sediment samples were conducted using gas chromatography-mass spectrometry. The vertical profiles of PAHs in the core sediments were assessed, possible sources and apportionment were identified, and the toxicity risk of the core sediments was determined. The results from the sediment analyses showed that total concentrations of the 16 PAHs varied from 11774 ± 4244 to 16755 ± 4593 ng/g dry weight (dw). Generally, the vertical profiles of the PAHs in the sediment cores exhibited a decreasing trend from the top to the lower levels of the S1 core and an increasing trend of PAHs from the top to the lower levels of the S2 and S3 cores. Among the core sediment samples, the five- and six-ring PAHs were predominantly in the S1 core, ranging from 42 to 54 %, whereas the composition of the PAHs in the S2 and S3 cores were distributed equally across three groups: two- and three-ring, four-ring, and five- and six-ring PAHs. The results indicated that PAH contamination at the site of the S1 core had a different source. The molecular indices and principal component analyses with multivariate linear regression were used to determine the source contributions, with the results showing that the contributions of coal, oil-related, and vehicle sources were 38.6, 35.9, and 25.5 %, respectively. A PAH toxicity assessment using the mean effect range-median quotient (m-ERM-q, 0.59-0.79), benzo[a]pyrene toxicity equivalent (TEQ(carc), 1466-1954 ng TEQ/g dw), and dioxin toxicity equivalent (TEQ(fish), 3036-4174 pg TEQ/g dw) identified the wharf as the most affected area. The results can be used for regular monitoring, and future pollution prevention and management should target the coal-based industries in this region for pollution reduction.

  7. Effects of the addition of different nitrogen sources in the tequila fermentation process at high sugar concentration.

    Science.gov (United States)

    Arrizon, J; Gschaedler, A

    2007-04-01

    To study the effect of the addition of different nitrogen sources at high sugar concentration in the tequila fermentation process. Fermentations were performed at high sugar concentration (170 g l(-1)) using Agave tequilana Weber blue variety with and without added nitrogen from different sources (ammonium sulfate; glutamic acid; a mixture of ammonium sulfate and amino acids) during the exponential phase of growth. All the additions increased the fermentation rate and alcohol efficiency. The level of synthesis of volatile compounds depended on the source added. The concentration of amyl alcohols and isobutanol were decreased while propanol and acetaldehyde concentration increased. The most efficient nitrogen sources for fermentation rate were ammonium sulfate and the mixture of ammonium sulfate and amino acids. The level of volatile compounds produced depended upon types of nitrogen. The synthesis of some volatile compounds increased while others decreased with nitrogen addition. The addition of nitrogen could be a strategy for improving the fermentation rate and efficiency in the tequila fermentation process at high sugar Agave tequilana concentration. Furthermore, the sensory quality of the final product may change because the synthesis of the volatile compounds is modified.

  8. Exposition by inhalation to the benzene, toluene, ethyl-benzene and xylenes (BTEX) in the air. Sources, measures and concentrations

    International Nuclear Information System (INIS)

    Del Gratta, F.; Durif, M.; Fagault, Y.; Zdanevitch, I.

    2004-12-01

    This document presents the main techniques today available to characterize the benzene, toluene, ethyl-benzene and xylene (BTEX) concentrations in the air for different contexts: urban and rural areas or around industrial installations but also indoor and occupational area. It provides information to guide laboratories and research departments. A synthesis gives also the main emissions sources of these compounds as reference concentrations measured in different environments. (A.L.B.)

  9. Regression analysis and categorical agreement of fluconazole disk zone diameters and minimum inhibitory concentration by broth microdilution of clinical isolates of Candida.

    Science.gov (United States)

    Aggarwal, P; Kashyap, B

    2017-06-01

    Rampant use of fluconazole in Candida infections has led to predominance of less susceptible non-albicans Candida over Candida albicans. The aim of the study was to determine if zone diameters around fluconazole disk can be used to estimate the minimum inhibitory concentration (MIC) for clinical isolates of Candida species and vice versa. Categorical agreement between the Clinical & Laboratory Standards Institute (CLSI) recommended disk diffusion and CLSI broth microdilution method was sought for. Antifungal susceptibility testing by disk diffusion and Broth microdilution was done as per CLSI document M44-S3 and CLSI document M27-S4 for Candida isolates respectively. Regression analysis correlating zone diameters to MIC value was done. Pearson's correlation coefficient was calculated to determine correlation between disk zone diameters and MICs. Candida albicans (33.3%) was clearly outnumbered by other non-albicans species predominantly Candida tropicalis (42.5%) and Candida glabrata (18.4%). Ten percent of the strains were resistant to fluconazole by disk diffusion and 13% by broth microdilution. MIC range for Candida albicans and Candida tropicalis ranged from≤0.25-64μg/ml while that of Candida glabrata ranged from≤0.25-128μg/ml. Categorical agreement between disk diffusion and broth microdilution was 86.8%. Pearson's coefficient of correlation was -0.5975 indicating moderate negative correlation between the two variables. Zone sizes can be used to estimate the MIC values, although with limited accuracy. There should be a constant effort to upgrade the guidelines in view of new clinical data, and laboratories should make an active effort to incorporate them. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  10. Radiation-sanitary essessment of surface and ground water sources in the Chernobyl' NPP 30-km zone

    International Nuclear Information System (INIS)

    Prokopov, V.A.; Karachev, I.I.; Nagovitsina, L.I.; Borovikova, N.M.; Tolstopyatova, G.V.; Gelts, V.I.; Malenko, N.D.; Dan'ko, O.P.

    1992-01-01

    The quality of drinking water in artesian water-lines of the Pripyat' and Chernobyl' settlements fro the period of 1987-1991 is estimated. The flood-lands territory within the north trace boundaries, where Sr 90 activity amounts to approximately 10000 Ci, contributes most importantly into water contamination of the Pripyat' river and its tributaries. The portion of contaminated drains from flood-lands territory amounts to 40% and more of the 90 Sr intake from all sources of the Pripyat' river contamination. Essessment of the artesian water quality shows that drinking water is innocuous for health in respect to its composition. 90 Sr and 137 Cs content in artesian water in the Pripyat' and Chernobyl' settlements is lower than the maximum permissible concentration. 5 refs.; 1 tab

  11. Implications of soil mixing for NAPL source zone remediation: Column studies and modeling of field-scale systems.

    Science.gov (United States)

    Olson, Mitchell R; Sale, Tom C

    2015-01-01

    Soil remediation is often inhibited by subsurface heterogeneity, which constrains contaminant/reagent contact. Use of soil mixing techniques for reagent delivery provides a means to overcome contaminant/reagent contact limitations. Furthermore, soil mixing reduces the permeability of treated soils, thus extending the time for reactions to proceed. This paper describes research conducted to evaluate implications of soil mixing on remediation of non-aqueous phase liquid (NAPL) source zones. The research consisted of column studies and subsequent modeling of field-scale systems. For column studies, clean influent water was flushed through columns containing homogenized soils, granular zero valent iron (ZVI), and trichloroethene (TCE) NAPL. Within the columns, NAPL depletion occurred due to dissolution, followed by either column-effluent discharge or ZVI-mediated degradation. Complete removal of TCE NAPL from the columns occurred in 6-8 pore volumes of flow. However, most of the TCE (>96%) was discharged in the column effluent; less than 4% of TCE was degraded. The low fraction of TCE degraded is attributed to the short hydraulic residence time (10 m) and reducing permeability by one-or-more orders of magnitude, the residence time could be greatly extended, potentially for periods of years to decades. Model output indicates that the fraction of TCE degraded can be increased to >99.9%, given typical post-mixing soil permeability values. These results suggest that remediation performance can be greatly enhanced by combining contaminant degradation with an extended residence time. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. A comparative study of methanol as a supplementary carbon source for enhancing denitrification in primary and secondary anoxic zones.

    Science.gov (United States)

    Ginige, Maneesha P; Bowyer, Jocelyn C; Foley, Leah; Keller, Jürg; Yuan, Zhiguo

    2009-04-01

    A comparative study on the use of methanol as a supplementary carbon source to enhance denitrification in primary and secondary anoxic zones is reported. Three lab-scale sequencing batch reactors (SBR) were operated to achieve nitrogen and carbon removal from domestic wastewater. Methanol was added to the primary anoxic period of the first SBR, and to the secondary anoxic period of the second SBR. No methanol was added to the third SBR, which served as a control. The extent of improvement on the denitrification performance was found to be dependent on the reactor configuration. Addition to the secondary anoxic period is more effective when very low effluent nitrate levels are to be achieved and hence requires a relatively large amount of methanol. Adding a small amount of methanol to the secondary anoxic period may cause nitrite accumulation, which does not improve overall nitrogen removal. In the latter case, methanol should be added to the primary anoxic period. The addition of methanol can also improve biological phosphorus removal by creating anaerobic conditions and increasing the availability of organic carbon in wastewater for polyphosphate accumulating organisms. This potentially provides a cost-effective approach to phosphorus removal from wastewater with a low carbon content. New fluorescence in situ hybridisation (FISH) probes targeting methanol-utilising denitrifiers were designed using stable isotope probing. Microbial structure analysis of the sludges using the new and existing FISH probes clearly showed that the addition of methanol stimulated the growth of specific methanol-utilizing denitrifiers, which improved the capability of sludge to use methanol and ethanol for denitrification, but reduced its capability to use wastewater COD for denitrification. Unlike acetate, long-term application of methanol has no negative impact on the settling properties of the sludge.

  13. Total and bioavailable arsenic concentration in arid soils and its uptake by native plants from the pre-Andean zones in Chile.

    Science.gov (United States)

    Díaz, O; Tapia, Y; Pastene, R; Montes, S; Núñez, N; Vélez, D; Montoro, R

    2011-06-01

    Arsenic is the most important contaminant of the environment in northern Chile. Soil samples and plant organs from three native plant species, Pluchea absinthioides, Atriplex atacamensis and Lupinus microcarpus, were collected from arid zones in order to determine the total and bioavailable arsenic concentrations in soils and to assess the bioconcentration factor (BCF) and transport index (Ti) of arsenic in the plants. Total arsenic concentrations in soils (pH 8.3-8.5) where A. atacamensis and P. absinthioides were collected, reached levels considered to be contaminated (54.3 ± 15.4 and 52.9 ± 9.9 mg kg⁻¹, respectively), and these values were approximately ten times higher than in soils (pH 7.6) where L. microcarpus was collected. Bioavailable arsenic ranged from 0.18 to 0.42% of total arsenic concentration. In the three plant species, arsenic concentration in leaves were significantly (p ≤ 0.05) higher than in roots. L. microcarpus showed the highest arsenic concentration in its leaves (9.7 ± 1.6 mg kg⁻¹) and higher values of BCF (1.8) and Ti (6.1), indicating that this species has a greater capacity to accumulate and translocate the metalloid to the leaf than do the other species.

  14. Sources and processes affecting the distribution of dissolved Nd isotopes and concentrations in the West Pacific

    Science.gov (United States)

    Behrens, Melanie K.; Pahnke, Katharina; Schnetger, Bernhard; Brumsack, Hans-Jürgen

    2018-02-01

    In the Atlantic, where deep circulation is vigorous, the dissolved neodymium (Nd) isotopic composition (expressed as ɛNd) is largely controlled by water mass mixing. In contrast, the factors influencing the ɛNd distribution in the Pacific, marked by sluggish circulation, is not clear yet. Indication for regional overprints in the Pacific is given based on its bordering volcanic islands. Our study aims to clarify the impact and relative importance of different Nd sources (rivers, volcanic islands), vertical (bio)geochemical processes and lateral water mass transport in controlling dissolved ɛNd and Nd concentration ([Nd]) distributions in the West Pacific between South Korea and Fiji. We find indication for unradiogenic continental input from South Korean and Chinese rivers to the East China Sea. In the tropical West Pacific, volcanic islands supply Nd to surface and subsurface waters and modify their ɛNd to radiogenic values of up to +0.7. These radiogenic signatures allow detailed tracing of currents flowing to the east and differentiation from westward currents with open ocean Pacific ɛNd composition in the complex tropical Pacific zonal current system. Modified radiogenic ɛNd of West Pacific intermediate to bottom waters upstream or within our section also indicates non-conservative behavior of ɛNd due to boundary exchange at volcanic island margins, submarine ridges, and with hydrothermal particles. Only subsurface to deep waters (3000 m) in the open Northwest Pacific show conservative behavior of ɛNd. In contrast, we find a striking correlation of extremely low (down to 2.77 pmol/kg Nd) and laterally constant [Nd] with the high-salinity North and South Pacific Tropical Water, indicating lateral transport of preformed [Nd] from the North and South Pacific subtropical gyres into the study area. This observation also explains the previously observed low subsurface [Nd] in the tropical West Pacific. Similarly, Western South Pacific Central Water, Antarctic

  15. Source characterization and exposure modeling of gas-phase polycyclic aromatic hydrocarbon (PAH) concentrations in Southern California

    Science.gov (United States)

    Masri, Shahir; Li, Lianfa; Dang, Andy; Chung, Judith H.; Chen, Jiu-Chiuan; Fan, Zhi-Hua (Tina); Wu, Jun

    2018-03-01

    Airborne exposures to polycyclic aromatic hydrocarbons (PAHs) are associated with adverse health outcomes. Because personal air measurements of PAHs are labor intensive and costly, spatial PAH exposure models are useful for epidemiological studies. However, few studies provide adequate spatial coverage to reflect intra-urban variability of ambient PAHs. In this study, we collected 39-40 weekly gas-phase PAH samples in southern California twice in summer and twice in winter, 2009, in order to characterize PAH source contributions and develop spatial models that can estimate gas-phase PAH concentrations at a high resolution. A spatial mixed regression model was constructed, including such variables as roadway, traffic, land-use, vegetation index, commercial cooking facilities, meteorology, and population density. Cross validation of the model resulted in an R2 of 0.66 for summer and 0.77 for winter. Results showed higher total PAH concentrations in winter. Pyrogenic sources, such as fossil fuels and diesel exhaust, were the most dominant contributors to total PAHs. PAH sources varied by season, with a higher fossil fuel and wood burning contribution in winter. Spatial autocorrelation accounted for a substantial amount of the variance in total PAH concentrations for both winter (56%) and summer (19%). In summer, other key variables explaining the variance included meteorological factors (9%), population density (15%), and roadway length (21%). In winter, the variance was also explained by traffic density (16%). In this study, source characterization confirmed the dominance of traffic and other fossil fuel sources to total measured gas-phase PAH concentrations while a spatial exposure model identified key predictors of PAH concentrations. Gas-phase PAH source characterization and exposure estimation is of high utility to epidemiologist and policy makers interested in understanding the health impacts of gas-phase PAHs and strategies to reduce emissions.

  16. Seasonal and Spatial Variations of Heavy Metals in Two Typical Chinese Rivers: Concentrations, Environmental Risks, and Possible Sources

    Science.gov (United States)

    Yao, Hong; Qian, Xin; Gao, Hailong; Wang, Yulei; Xia, Bisheng

    2014-01-01

    Ten metals were analyzed in samples collected in three seasons (the dry season, the early rainy season, and the late rainy season) from two rivers in China. No observed toxic effect concentrations were used to estimate the risks. The possible sources of the metals in each season, and the dominant source(s) at each site, were assessed using principal components analysis. The metal concentrations in the area studied were found, using t-tests, to vary both seasonally and spatially (P = 0.05). The potential risks in different seasons decreased in the order: early rainy season > dry season > late rainy season, and Cd was the dominant contributor to the total risks associated with heavy metal pollution in the two rivers. The high population and industrial site densities in the Taihu basin have had negative influences on the two rivers. The river that is used as a source of drinking water (the Taipu River) had a low average level of risks caused by the metals. Metals accumulated in environmental media were the main possible sources in the dry season, and emissions from mechanical manufacturing enterprises were the main possible sources in the rainy season. The river in the industrial area (the Wusong River) had a moderate level of risk caused by the metals, and the main sources were industrial emissions. The seasonal and spatial distributions of the heavy metals mean that risk prevention and mitigation measures should be targeted taking these variations into account. PMID:25407421

  17. Seasonal and Spatial Variations of Heavy Metals in Two Typical Chinese Rivers: Concentrations, Environmental Risks, and Possible Sources

    Directory of Open Access Journals (Sweden)

    Hong Yao

    2014-11-01

    Full Text Available Ten metals were analyzed in samples collected in three seasons (the dry season, the early rainy season, and the late rainy season from two rivers in China. No observed toxic effect concentrations were used to estimate the risks. The possible sources of the metals in each season, and the dominant source(s at each site, were assessed using principal components analysis. The metal concentrations in the area studied were found, using t-tests, to vary both seasonally and spatially (P = 0.05. The potential risks in different seasons decreased in the order: early rainy season > dry season > late rainy season, and Cd was the dominant contributor to the total risks associated with heavy metal pollution in the two rivers. The high population and industrial site densities in the Taihu basin have had negative influences on the two rivers. The river that is used as a source of drinking water (the Taipu River had a low average level of risks caused by the metals. Metals accumulated in environmental media were the main possible sources in the dry season, and emissions from mechanical manufacturing enterprises were the main possible sources in the rainy season. The river in the industrial area (the Wusong River had a moderate level of risk caused by the metals, and the main sources were industrial emissions. The seasonal and spatial distributions of the heavy metals mean that risk prevention and mitigation measures should be targeted taking these variations into account.

  18. Concentrations of polycyclic aromatic hydrocarbons in New York City community garden soils: Potential sources and influential factors.

    Science.gov (United States)

    Marquez-Bravo, Lydia G; Briggs, Dean; Shayler, Hannah; McBride, Murray; Lopp, Donna; Stone, Edie; Ferenz, Gretchen; Bogdan, Kenneth G; Mitchell, Rebecca G; Spliethoff, Henry M

    2016-02-01

    A total of 69 soil samples from 20 community gardens in New York City (New York, USA) were collected and analyzed for 23 polycyclic aromatic hydrocarbons (PAHs) and black carbon. For each garden, samples were collected from nongrowing areas (non-bed) and from vegetable-growing beds, including beds with and without visible sources of PAHs. The sum of the US Environmental Protection Agency's 16 priority PAHs ranged up to 150 mg/kg, and the median (5.4 mg/kg) and mean (14.2 mg/kg) were similar to those previously reported for urban areas in the northeast United States. Isomer ratios indicated that the main sources of PAHs were petroleum, coal, and wood combustion. The PAH concentrations were significantly and positively associated with black carbon and with modeled air PAH concentrations, suggesting a consistent relationship between historical deposition of atmospheric carbon-adsorbed PAHs and current PAH soil concentrations. Median PAH soil concentration from non-bed areas was higher (7.4 mg/kg) than median concentration from beds in the same garden (4.0 mg/kg), and significantly higher than the median from beds without visible sources of PAHs (3.5 mg/kg). Median PAH concentration in beds from gardens with records of soil amendments was 58% lower compared with beds from gardens without those records. These results suggest that gardening practices in garden beds without visible sources of PAHs contribute to reduce PAH soil concentrations. © 2015 SETAC.

  19. Effect of starch source (corn, oats or wheat) and concentration on fermentation by equine fecal microbiota in vitro

    Science.gov (United States)

    Aims: The goal was to determine the effect of starch source (corn, oats and wheat) and concentration on: 1) total amylolytic bacteria, Group D Gram-positive cocci (GPC), lactobacilli, and lactate-utilizing bacteria, and 2) fermentation by equine microflora. Methods and Results: When fecal washed cel...

  20. Technical basis for selecting radionuclide concentrations for use in Hanford tank basis for interim operation source term

    International Nuclear Information System (INIS)

    Cowley, W.L.

    1997-01-01

    This paper describes the development of a radiological source term for waste tanks at the Hanford Site Nuclear Reservation. It describes the methodology used to identify the most important radionuclides, determine appropriate concentrations, and define unit liter doses. An example of how unit liter doses are used is given

  1. Apportionment of the sources of high fine particulate matter concentration events in a developing aerotropolis in Taoyuan, Taiwan.

    Science.gov (United States)

    Chuang, Ming-Tung; Chen, Yu-Chieh; Lee, Chung-Te; Cheng, Chung-Hao; Tsai, Yu-Jen; Chang, Shih-Yu; Su, Zhen-Sen

    2016-07-01

    To investigate the characteristics and contributions of the sources of fine particulate matter with a size of up to 2.5 μm (PM2.5) during the period when pollution events could easily occur in Taoyuan aerotropolis, Taiwan, this study conducted sampling at three-day intervals from September 2014 to January 2015. Based on the mass concentration of PM2.5, the sampling days were classified into high PM2.5 concentration event days (PM2.5>35 μg m(-3)) and non-event days (PM2.5<35 μg m(-3)). In addition, the chemical species, including water-soluble inorganic ions, carbonaceous components, and metal elements, were analyzed. The sources of pollution and their contributions were estimated using the positive matrix factorization (PMF) model. Furthermore, the effect of the weather type on the measurement results was also explored based on wind field conditions. The mass fractions of Cl(-) and NO3(-) increased when a high PM2.5 concentration event occurred, and they were also higher under local emitted conditions than under long range transported conditions, indicating that secondary nitrate aerosols were the major increasing local species that caused high PM2.5 concentration events. Seven sources of pollution could be distinguished using the PMF model on the basis of the characteristics of the species. Industrial emissions, coal combustion/urban waste incineration, and local emissions from diesel/gasoline vehicles were the main sources that contributed to pollution on high PM2.5 concentration event days. In order to reduction of high PM2.5 concentration events, the control of diesel and gasoline vehicle emission is important and should be given priority. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Source contributions to PM10 and arsenic concentrations in Central Chile using positive matrix factorization

    Science.gov (United States)

    Hedberg, Emma; Gidhagen, Lars; Johansson, Christer

    Sampling of particles (PM10) was conducted during a one-year period at two rural sites in Central Chile, Quillota and Linares. The samples were analyzed for elemental composition. The data sets have undergone source-receptor analyses in order to estimate the sources and their abundance's in the PM10 size fraction, by using the factor analytical method positive matrix factorization (PMF). The analysis showed that PM10 was dominated by soil resuspension at both sites during the summer months, while during winter traffic dominated the particle mass at Quillota and local wood burning dominated the particle mass at Linares. Two copper smelters impacted the Quillota station, and contributed to 10% and 16% of PM10 as an average during summer and winter, respectively. One smelter impacted Linares by 8% and 19% of PM10 in the summer and winter, respectively. For arsenic the two smelters accounted for 87% of the monitored arsenic levels at Quillota and at Linares one smelter contributed with 72% of the measured mass. In comparison with PMF, the use of a dispersion model tended to overestimate the smelter contribution to arsenic levels at both sites. The robustness of the PMF model was tested by using randomly reduced data sets, where 85%, 70%, 50% and 33% of the samples were included. In this way the ability of the model to reconstruct the sources initially found by the original data set could be tested. On average for all sources the relative standard deviation increased from 7% to 25% for the variables identifying the sources, when decreasing the data set from 85% to 33% of the samples, indicating that the solution initially found was very stable to begin with. But it was also noted that sources due to industrial or combustion processes were more sensitive for the size of the data set, compared to the natural sources as local soil and sea spray sources.

  3. Elevated Arsenic and Uranium Concentrations in Unregulated Water Sources on the Navajo Nation, USA

    OpenAIRE

    Hoover, Joseph; Gonzales, Melissa; Shuey, Chris; Barney, Yolanda; Lewis, Johnnye

    2016-01-01

    Regional water pollution and use of unregulated water sources can be an important mixed metals exposure pathway for rural populations located in areas with limited water infrastructure and an extensive mining history.?Using censored data analysis and mapping techniques we analyzed the joint geospatial distribution of arsenic and uranium in unregulated water sources throughout the Navajo Nation, where over 500 abandoned uranium mine sites are located in the rural southwestern United States. Re...

  4. Airborne black carbon concentrations over an urban region in western India-temporal variability, effects of meteorology, and source regions.

    Science.gov (United States)

    Bapna, Mukund; Sunder Raman, Ramya; Ramachandran, S; Rajesh, T A

    2013-03-01

    This study characterizes over 5 years of high time resolution (5 min), airborne black carbon (BC) concentrations (July 2003 to December 2008) measured over Ahmedabad, an urban region in western India. The data were used to obtain different time averages of BC concentrations, and these averages were then used to assess the diurnal, seasonal, and annual variability of BC over the study region. Assessment of diurnal variations revealed a strong association between BC concentrations and vehicular traffic. Peaks in BC concentration were co-incident with the morning (0730 to 0830, LST) and late evening (1930 to 2030, LST) rush hour traffic. Additionally, diurnal variability in BC concentrations during major festivals (Diwali and Dushera during the months of October/November) revealed an increase in BC concentrations due to fireworks displays. Maximum half hourly BC concentrations during the festival days were as high as 79.8 μg m(-3). However, the high concentrations rapidly decayed suggesting that local meteorology during the festive season was favorable for aerosol dispersion. A multiple linear regression (MLR) model with BC as the dependent variable and meteorological parameters as independent variables was fitted. The variability in temperature, humidity, wind speed, and wind direction accounted for about 49% of the variability in measured BC concentrations. Conditional probability function (CPF) analysis was used to identify the geographical location of local source regions contributing to the effective BC measured (at 880 nm) at the receptor site. The east north-east (ENE) direction to the receptor was identified as a major source region. National highway (NH8) and two coal-fired thermal power stations (at Gandhinagar and Sabarmati) were located in the identified direction, suggesting that local traffic and power plant emissions were likely contributors to the measured BC.

  5. Sources and Dynamic Processes Controlling Background and Peak Concentrations of TGM in Nanjing, China

    Directory of Open Access Journals (Sweden)

    Casey B. Hall

    2014-03-01

    Full Text Available Total gaseous mercury (TGM data from urban Nanjing, at the western edge of the Yangtze River Delta (YRD region in China, over nine months, were analyzed for peak and background mercury concentrations. The background concentration of TGM was found to be 2.2 ng∙m−3. In examining episodic influences of free tropospheric air masses on the surface TGM concentrations in Nanjing, we hypothesize heterogeneity in the global distribution of TGM concentrations in the free troposphere. The nine-month averaged diurnal cycles of TGM indicate a strong co-emission with SO2 and an underestimation of greater than 80% TGM emissions in current inventories. Regular peak concentrations of mercury were investigated and the major causes were YRD emissions, transport from rural areas, and monsoonal transport. Transport of rural emissions is hypothesized to be from illegal artisanal small-scale gold mining that are currently missing in the emission inventories. Enhancement of TGM associated with summer monsoon contributed to a maximum TGM concentration in mid-May–early June, an inverse seasonality in comparison to most other observations in China, North America, and Europe.

  6. Identification of emission sources of particle-bound polycyclic aromatic hydrocarbons in the vicinity of the industrial zone of the city of Novi Sad

    OpenAIRE

    Jovčić Nataša S.; Radonić Jelena R.; Turk-Sekulić Maja M.; Vojinović-Miloradov Mirjana B.; Popov Srđan B.

    2013-01-01

    Data on polycyclic aromatic hydrocarbons (PAHs) in ambient air accessed at selected locations in the vicinity of the industrial zone of the city of Novi Sad, Serbia, have been presented and analyzed in order to determine seasonal and spatial variations and to identify emission sources of particle-bound PAHs. Previous studies have demonstrated that the major contributors of PAHs in urban areas are the emissions from vehicle exhaust, and emissions releases from industrial processes like a...

  7. High summertime aerosol organic functional group concentrations from marine and seabird sources at Ross Island, Antarctica, during AWARE

    Directory of Open Access Journals (Sweden)

    J. Liu

    2018-06-01

    Full Text Available Observations of the organic components of the natural aerosol are scarce in Antarctica, which limits our understanding of natural aerosols and their connection to seasonal and spatial patterns of cloud albedo in the region. From November 2015 to December 2016, the ARM West Antarctic Radiation Experiment (AWARE measured submicron aerosol properties near McMurdo Station at the southern tip of Ross Island. Submicron organic mass (OM, particle number, and cloud condensation nuclei concentrations were higher in summer than other seasons. The measurements included a range of compositions and concentrations that likely reflected both local anthropogenic emissions and natural background sources. We isolated the natural organic components by separating a natural factor and a local combustion factor. The natural OM was 150 times higher in summer than in winter. The local anthropogenic emissions were not hygroscopic and had little contribution to the CCN concentrations. Natural sources that included marine sea spray and seabird emissions contributed 56 % OM in summer but only 3 % in winter. The natural OM had high hydroxyl group fraction (55 %, 6 % alkane, and 6 % amine group mass, consistent with marine organic composition. In addition, the Fourier transform infrared (FTIR spectra showed the natural sources of organic aerosol were characterized by amide group absorption, which may be from seabird populations. Carboxylic acid group contributions were high in summer and associated with natural sources, likely forming by secondary reactions.

  8. Influence of ambient (outdoor) sources on residential indoor and personal PM2.5 concentrations: analyses of RIOPA data.

    Science.gov (United States)

    Meng, Qing Yu; Turpin, Barbara J; Korn, Leo; Weisel, Clifford P; Morandi, Maria; Colome, Steven; Zhang, Junfeng Jim; Stock, Thomas; Spektor, Dalia; Winer, Arthur; Zhang, Lin; Lee, Jong Hoon; Giovanetti, Robert; Cui, William; Kwon, Jaymin; Alimokhtari, Shahnaz; Shendell, Derek; Jones, Jennifer; Farrar, Corice; Maberti, Silvia

    2005-01-01

    The Relationship of Indoor, Outdoor and Personal Air (RIOPA) study was designed to investigate residential indoor, outdoor and personal exposures to several classes of air pollutants, including volatile organic compounds, carbonyls and fine particles (PM2.5). Samples were collected from summer, 1999 to spring, 2001 in Houston (TX), Los Angeles (CA) and Elizabeth (NJ). Indoor, outdoor and personal PM2.5 samples were collected at 212 nonsmoking residences, 162 of which were sampled twice. Some homes were chosen due to close proximity to ambient sources of one or more target analytes, while others were farther from sources. Median indoor, outdoor and personal PM2.5 mass concentrations for these three sites were 14.4, 15.5 and 31.4 microg/m3, respectively. The contributions of ambient (outdoor) and nonambient sources to indoor and personal concentrations were quantified using a single compartment box model with measured air exchange rate and a random component superposition (RCS) statistical model. The median contribution of ambient sources to indoor PM2.5 concentrations using the mass balance approach was estimated to be 56% for all study homes (63%, 52% and 33% for California, New Jersey and Texas study homes, respectively). Reasonable variations in model assumptions alter median ambient contributions by less than 20%. The mean of the distribution of ambient contributions across study homes agreed well for the mass balance and RCS models, but the distribution was somewhat broader when calculated using the mass balance model with measured air exchange rates.

  9. Concentrations and sources of polycyclic aromatic hydrocarbons in surface coastal sediments of the northern Gulf of Mexico

    Science.gov (United States)

    2014-01-01

    Background Coastal sediments in the northern Gulf of Mexico have a high potential of being contaminated by petroleum hydrocarbons, such as polycyclic aromatic hydrocarbons (PAHs), due to extensive petroleum exploration and transportation activities. In this study we evaluated the spatial distribution and contamination sources of PAHs, as well as the bioavailable fraction in the bulk PAH pool, in surface marsh and shelf sediments (top 5 cm) of the northern Gulf of Mexico. Results PAH concentrations in this region ranged from 100 to 856 ng g−1, with the highest concentrations in Mississippi River mouth sediments followed by marsh sediments and then the lowest concentrations in shelf sediments. The PAH concentrations correlated positively with atomic C/N ratios of sedimentary organic matter (OM), suggesting that terrestrial OM preferentially sorbs PAHs relative to marine OM. PAHs with 2 rings were more abundant than those with 5–6 rings in continental shelf sediments, while the opposite was found in marsh sediments. This distribution pattern suggests different contamination sources between shelf and marsh sediments. Based on diagnostic ratios of PAH isomers and principal component analysis, shelf sediment PAHs were petrogenic and those from marsh sediments were pyrogenic. The proportions of bioavailable PAHs in total PAHs were low, ranging from 0.02% to 0.06%, with higher fractions found in marsh than shelf sediments. Conclusion PAH distribution and composition differences between marsh and shelf sediments were influenced by grain size, contamination sources, and the types of organic matter associated with PAHs. Concentrations of PAHs in the study area were below effects low-range, suggesting a low risk to organisms and limited transfer of PAHs into food web. From the source analysis, PAHs in shelf sediments mainly originated from direct petroleum contamination, while those in marsh sediments were from combustion of fossil fuels. PMID:24641695

  10. Comparative Analysis of Fluoride Concentrations in Groundwaters in Northern and Southern Ghana: Implications for the Contaminant Sources

    Science.gov (United States)

    Sunkari, Emmanuel Daanoba; Zango, Musah Saeed; Korboe, Harriet Mateko

    2018-04-01

    Bongo and Sekyere South districts, both in the northern and southern parts of Ghana, respectively, have high populations living in rural areas and most of them use groundwater for drinking purposes. The groundwater in these areas is prone to contamination from natural and/or artificial sources. Therefore this study aims; (1) to present a comparative analysis of the fluoride concentration in groundwater samples from Bongo and Sekyere South districts and the associated groundwater-rock interaction that may be the cause for the varied fluoride concentrations, (2) to determine the leaching potential of fluoride from the host rocks as the possible mechanism for groundwater contamination. Sixty (60) groundwater samples from active pumping wells and twelve (12) rock samples from outcrops were collected from various communities in the two districts for fluoride concentration and mineralogical analysis. Based on the variations in fluoride concentration, fluoride spatial distribution maps were prepared using empirical Bayesian kriging interpolation method and analysed by means of hierarchical cluster analysis. The fluoride concentration in Bongo district varies between 1.71 and 4.0 mg/L, whereas that in Sekyere South district changes from 0.3 to 0.8 mg/L. From the mineralogical studies, biotite has the highest percentage in the Bongo district and has positive correlation with fluoride concentration in the analysed water samples than in the Sekyere South district. The elevated fluoride concentration in the Bongo district relative to the Sekyere South district is due to the dissolution of biotite in the groundwater and the sufficient groundwater-rock interaction since the water samples are mainly sourced from deeper boreholes. This high fluoride concentration has resulted in a plethora of reported cases of dental fluorosis and other health-related issues in Bongo.

  11. Concentrator optical characterization using computer mathematical modelling and point source testing

    Science.gov (United States)

    Dennison, E. W.; John, S. L.; Trentelman, G. F.

    1984-01-01

    The optical characteristics of a paraboloidal solar concentrator are analyzed using the intercept factor curve (a format for image data) to describe the results of a mathematical model and to represent reduced data from experimental testing. This procedure makes it possible not only to test an assembled concentrator, but also to evaluate single optical panels or to conduct non-solar tests of an assembled concentrator. The use of three-dimensional ray tracing computer programs to calculate the mathematical model is described. These ray tracing programs can include any type of optical configuration from simple paraboloids to array of spherical facets and can be adapted to microcomputers or larger computers, which can graphically display real-time comparison of calculated and measured data.

  12. Apportionment of the sources of high fine particulate matter concentration events in a developing aerotropolis in Taoyuan, Taiwan

    International Nuclear Information System (INIS)

    Chuang, Ming-Tung; Chen, Yu-Chieh; Lee, Chung-Te; Cheng, Chung-Hao; Tsai, Yu-Jen; Chang, Shih-Yu; Su, Zhen-Sen

    2016-01-01

    To investigate the characteristics and contributions of the sources of fine particulate matter with a size of up to 2.5 μm (PM 2.5 ) during the period when pollution events could easily occur in Taoyuan aerotropolis, Taiwan, this study conducted sampling at three-day intervals from September 2014 to January 2015. Based on the mass concentration of PM 2.5 , the sampling days were classified into high PM 2.5 concentration event days (PM 2.5 >35 μg m −3 ) and non-event days (PM 2.5 <35 μg m −3 ). In addition, the chemical species, including water-soluble inorganic ions, carbonaceous components, and metal elements, were analyzed. The sources of pollution and their contributions were estimated using the positive matrix factorization (PMF) model. Furthermore, the effect of the weather type on the measurement results was also explored based on wind field conditions. The mass fractions of Cl − and NO 3 − increased when a high PM 2.5 concentration event occurred, and they were also higher under local emitted conditions than under long range transported conditions, indicating that secondary nitrate aerosols were the major increasing local species that caused high PM 2.5 concentration events. Seven sources of pollution could be distinguished using the PMF model on the basis of the characteristics of the species. Industrial emissions, coal combustion/urban waste incineration, and local emissions from diesel/gasoline vehicles were the main sources that contributed to pollution on high PM 2.5 concentration event days. In order to reduction of high PM 2.5 concentration events, the control of diesel and gasoline vehicle emission is important and should be given priority. - Highlights: • The mass fractions of NH 4 + , K + , Cl − and NO 3 − increased during PM 2.5 event days. • Reduction of coal combustion/urban waste incineration emissions should be prioritized. • The control of vehicle emission is important in the locally emitted periods. • Secondary

  13. Analysis of source regions and meteorological factors for the variability of spring PM10 concentrations in Seoul, Korea

    Science.gov (United States)

    Lee, Jangho; Kim, Kwang-Yul

    2018-02-01

    CSEOF analysis is applied for the springtime (March, April, May) daily PM10 concentrations measured at 23 Ministry of Environment stations in Seoul, Korea for the period of 2003-2012. Six meteorological variables at 12 pressure levels are also acquired from the ERA Interim reanalysis datasets. CSEOF analysis is conducted for each meteorological variable over East Asia. Regression analysis is conducted in CSEOF space between the PM10 concentrations and individual meteorological variables to identify associated atmospheric conditions for each CSEOF mode. By adding the regressed loading vectors with the mean meteorological fields, the daily atmospheric conditions are obtained for the first five CSEOF modes. Then, HYSPLIT model is run with the atmospheric conditions for each CSEOF mode in order to back trace the air parcels and dust reaching Seoul. The K-means clustering algorithm is applied to identify major source regions for each CSEOF mode of the PM10 concentrations in Seoul. Three main source regions identified based on the mean fields are: (1) northern Taklamakan Desert (NTD), (2) Gobi Desert and (GD), and (3) East China industrial area (ECI). The main source regions for the mean meteorological fields are consistent with those of previous study; 41% of the source locations are located in GD followed by ECI (37%) and NTD (21%). Back trajectory calculations based on CSEOF analysis of meteorological variables identify distinct source characteristics associated with each CSEOF mode and greatly facilitate the interpretation of the PM10 variability in Seoul in terms of transportation route and meteorological conditions including the source area.

  14. Hybrid ATDL-gamma distribution model for predicting area source acid gas concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Jakeman, A J; Taylor, J A

    1985-01-01

    An air quality model is developed to predict the distribution of concentrations of acid gas in an urban airshed. The model is hybrid in character, combining reliable features of a deterministic ATDL-based model with statistical distributional approaches. The gamma distribution was identified from a range of distributional models as the best model. The paper shows that the assumptions of a previous hybrid model may be relaxed and presents a methodology for characterizing the uncertainty associated with model predictions. Results are demonstrated for the 98-percentile predictions of 24-h average data over annual periods at six monitoring sites. This percentile relates to the World Health Organization goal for acid gas concentrations.

  15. Atmospheric mercury concentration and chemical speciation at a rural site in Beijing, China: implications of mercury emission sources

    Directory of Open Access Journals (Sweden)

    L. Zhang

    2013-10-01

    Full Text Available Continuous measurements of atmospheric mercury concentration and speciation play a key role in identifying mercury sources and its behavior in the atmosphere. In this study, speciated atmospheric mercury including gaseous elemental mercury (GEM, reactive gaseous mercury (RGM and particle-bound mercury (PBM were continuously measured at Miyun, a rural site in Beijing, China, from December 2008 to November 2009. The average GEM, RGM and PBM concentrations were found to be 3.22 ± 1.74, 10.1 ± 18.8 and 98.2 ± 112.7 pg m−3, respectively, about 2–20 times higher than the background concentration of the Northern Hemisphere. The results indicated that atmospheric mercury concentrations in northern China were highly affected by anthropogenic emissions. The atmospheric mercury showed obvious seasonal variations, with the highest seasonal average GEM concentration in summer (3.48 ng m−3 and the lowest value in winter (2.66 ng m−3. In autumn and winter a diurnal variation of GEM was observed, with peak levels in the late afternoon till midnight. Most of the high RGM concentration values occurred in the afternoon of all seasons due to the higher oxidation. The PBM concentration was higher in early morning of all seasons because of the the temperature inversion that increases in depth as the night proceeds. The ratio of GEM to CO indicates that residential boilers play an important role in the elevation of GEM in winter. The ratio of RGM to O3 could be an indicator of the contribution of local primary sources. The ratio of PBM to PM2.5 reveals that the air mass from the east and southwest of the site in spring and summer carries more atmospheric mercury. The HYSPLIT back-trajectory analysis indicated that the monitoring site is affected by local, regional and interregional sources simultaneously during heavy pollution episodes. The results from the potential source contribution function (PSCF model indicate that the atmospheric transport

  16. Investigation of gasoline distributions within petrol stations: spatial and seasonal concentrations, sources, mitigation measures, and occupationally exposed symptoms.

    Science.gov (United States)

    Sairat, Theerapong; Homwuttiwong, Sahalaph; Homwutthiwong, Kritsana; Ongwandee, Maneerat

    2015-09-01

    We measured levels of VOCs and determined the distributions of benzene concentrations over the area of two petrol stations in all three seasons. Using the concentrations and sampling positions, we created isoconcentration contour maps. The average concentrations ranged 18-1288 μg m(-3) for benzene and 12-81 μg m(-3) for toluene. The contour maps indicate that high-level contours of benzene were found not only at the fuel dispenser areas but also at the storage tank refilling points, open drainage areas where gasoline-polluted wastewater was flowing, and the auto service center located within the station area. An assessment of the benzene to toluene ratio contour plots implicates that airborne benzene and toluene near the fuel dispenser area were attributed to gasoline evaporation although one of the studied stations may be influenced by other VOC sources besides gasoline evaporation. Additionally, during the routine refilling of the underground fuel storage tanks by a tank truck, the ambient levels of benzene and toluene increased tremendously. The implementation of source control by replacing old dispensers with new fuel dispensers that have an efficient cutoff feature and increased delivery speed can reduce spatial benzene concentrations by 77%. Furthermore, a questionnaire survey among 63 service attendants in ten stations revealed that headache was the most reported health complaint with a response rate of 32%, followed by fatigue with 20%. These prominent symptoms could be related to an exposure to high benzene concentrations.

  17. Using trace element concentrations in Corbicula fluminea to identify potential sources of contamination in an urban river

    International Nuclear Information System (INIS)

    Loeffler Peltier, Gretchen; Meyer, Judith L.; Jagoe, Charles H.; Hopkins, William A.

    2008-01-01

    We used the biomonitor, Corbicula fluminea, to investigate the contributions of trace elements associated with different point sources and land uses in a large river. Trace elements were analyzed in tissues of clams collected from 15 tributary streams draining five land use or point source types: agriculture, forest, urban, coal-fired power plant (CFPP), and wastewater (WWTP). Clams from forested catchments had elevated Hg concentrations, and concentrations of arsenic and selenium were highest (5.0 ± 0.2 and 13.6 ± 0.9 μg g -1 dry mass (DM), respectively) in clams from CFPP sites. Cadmium concentrations were significantly higher in clams from urban and CFPP sites (4.1 ± 0.2 and 3.6 ± 0.9 μg g -1 DM, respectively). Non-metric multidimensional scaling (NMS) of tissue concentrations in clams clustered at CFPP and forest/agriculture sites at opposite ends of the ordination space, and the distribution of sites was driven by Cu, Zn, Cd, and Hg. - C. fluminea collected downstream of CFPPs had elevated tissue concentrations of trace elements

  18. Source contribution analysis of surface particulate polycyclic aromatic hydrocarbon concentrations in northeastern Asia by source–receptor relationships

    International Nuclear Information System (INIS)

    Inomata, Yayoi; Kajino, Mizuo; Sato, Keiichi; Ohara, Toshimasa; Kurokawa, Jun-ichi; Ueda, Hiromasa; Tang, Ning; Hayakawa, Kazuichi; Ohizumi, Tsuyoshi; Akimoto, Hajime

    2013-01-01

    We analyzed the source–receptor relationships for particulate polycyclic aromatic hydrocarbon (PAH) concentrations in northeastern Asia using an aerosol chemical transport model. The model successfully simulated the observed concentrations. In Beijing (China) benzo[a]pyren (BaP) concentrations are due to emissions from its own domain. In Noto, Oki and Tsushima (Japan), transboundary transport from northern China (>40°N, 40–60%) and central China (30–40°N, 10–40%) largely influences BaP concentrations from winter to spring, whereas the relative contribution from central China is dominant (90%) in Hedo. In the summer, the contribution from Japanese domestic sources increases (40–80%) at the 4 sites. Contributions from Japan and Russia are additional source of BaP over the northwestern Pacific Ocean in summer. The contribution rates for the concentrations from each domain are different among PAH species depending on their particulate phase oxidation rates. Reaction with O 3 on particulate surfaces may be an important component of the PAH oxidation processes. -- Highlights: •Source–receptor analysis was conducted for investigating PAHs in northeast Asia. •In winter, transboundary transport from China is large contribution in leeward. •Relative contribution from Korea, Japan, and eastern Russia is increased in summer. •This seasonal variation is strongly controlled by the meteorological conditions. •The transport distance is different among PAH species. -- Transboundary transport of PAHs in northeast Asia was investigated by source–receptor analysis

  19. Monitoring of THMs Concentration in Isfahan Water Distribution System and Zoning by GIS, a Case Study in the Center of Iran

    Directory of Open Access Journals (Sweden)

    Amir Mohammadi

    2016-01-01

    Full Text Available Trihalomethanes (THMs formation in treated water is a consequence of a reaction between the chlorine used for water disinfection and some natural organic matters. The objectives of the present study were monitoring of THMs concentration in Isfahan (A metropolis city in center of Iran water distribution network (IWDN, evaluation factors that affect the THMs formation potential and identification of critical points by using geographical information system (GIS. The study was performed in summer months of 2014. For sampling point's selection, city divided into 30 zones and water quality parameters such as pH, Electric Conductivity (EC, residual Chlorine, Total Organic Carbon (TOC and THMs of IWDN measured. Multi regression analysis was used to estimate the correlation between THMs formation and these variables. While the statistical analysis with Spearman non-parametric correlation coefficients showed a positive correlation between distance from treatment plant and THMs concentration(r=0.45, P =0.01 and negative strong correlation(r=-0.95, p>0.001 between THMs and TOC concentrations, there was no strong significant relationship between THMs formation in IWDN and some variables including pH, temperature and residual Chlorine. The results reveal that the average value of the THMs at sampling points for summer attained 42.56 ppb which was lower than the EPA and WHO standards. It is recommended that the distance from the treatment plant was used as an effective parameter for estimation of THMs formation potential.

  20. Effect of dietary starch source and concentration on equine fecal microbiota

    Science.gov (United States)

    Starch from corn is less susceptible to equine small intestinal digestion than starch from oats, and starch that reaches the hindgut can be utilized by the microbiota. The objective of the current study was to examine the effects of starch source on equine fecal microbiota. Thirty horses were assig...

  1. Concentration and shear rate dependence of solution viscosity for arabinoxylans from different sources

    Science.gov (United States)

    Arabinoxylans are cell wall polysaccharides abundant in plants. Alkaline extraction is commonly used to isolate arabinoxylans from cell wall rich materials, such as cereal brans, crop residues etc. While arabinoxylans from certain sources such as wheat endosperm, corn bran and rye bran have been wid...

  2. Physiology of Aspergillus niger in Oxygen-Limited Continuous Cultures: Influence of Aeration, Carbon Source Concentration and Dilution Rate

    DEFF Research Database (Denmark)

    Diano, Audrey; Peeters, J.; Dynesen, Jens Østergaard

    2009-01-01

    In industrial production of enzymes using the filamentous fungus Aspergilhis niger supply of sufficient oxygen is often a limitation, resulting in the formation of by-products such as polyols. In order to identify the mechanisms behind formation of the different by-products we studied the effect...... of low oxygen availability, at different carbon source concentrations and at different specific growth rates, on the metabolism of A. niger, using continuous cultures. The results show that there is an increase in the production of tricarboxylic acid (TCA) cycle intermediates at low oxygen concentrations...

  3. Crimea-Kopet Dagh zone of concentrated orogenic deformations as a transregional late collisional right-lateral strike-slip fault

    Science.gov (United States)

    Patina, I. S.; Leonov, Yu. G.; Volozh, Yu. A.; Kopp, M. L.; Antipov, M. P.

    2017-07-01

    It is shown that the Crimea, Caucasus, and Kopet Dagh fold systems make up a single whole unified by a lithospheric strike-slip fault zone of concentrated dislocations. The strike-slip fault that dissects the sedimentary cover and consolidated crust is rooted in subcrustal layers of the mantle. The notions about strike-slip dislocations in the structure of the Crimea-Kopet Dagh System are considered. Comparative analysis of structure, age, and amplitude of strike-slip fault segments is carried out. The effect of strike-slip faulting on the deep-seated and near-surface structure of the Earth's crust is considered. Based on estimation of strike-slip offsets, the paleogeography of Paleogene basins is refined; their initial contours, which have been disturbed and fragmented by slipping motion strike-slip displacement, have been reconstructed.

  4. Lyophilization and Reconstitution of Reverse-Osmosis Concentrated Natural Organic Matter from a Drinking Water Source

    Science.gov (United States)

    Disinfection by-product (DBP) research can be complicated by difficulties in shipping large water quantities and changing natural organic matter (NOM) characteristics over time. To overcome these issues, it is advantageous to have a reliable method for concentrating NOM with min...

  5. Biogas from Agricultural Residues as Energy Source in Hybrid Concentrated Solar Power

    NARCIS (Netherlands)

    Corré, W.J.; Conijn, J.G.

    2016-01-01

    This paper explores the possibilities of sustainable biogas use for hybridisation of Concentrated Solar Power (HCSP) in Europe. The optimal system for the use of biogas from agricultural residues (manure and crop residues) in HCSP involves anaerobic digestion with upgrading of biogas to

  6. Radon concentration assessment in water sources of public drinking of Covilhã's county, Portugal

    Directory of Open Access Journals (Sweden)

    M. Inácio

    2017-04-01

    Radon concentration measurements were performed on thirty three samples collected from water wells at different depths and types of aquifers, at Covilhã's County, Portugal with the radon gas analyser DURRIDGE RAD7. Twenty three, of the total of water samples collected, gave, values over 100 Bq/L, being that 1690 Bq/L was the highest measured value.

  7. Observed and Modeled Tritium Concentrations in the Terrestrial Food Chain near a Continuous Atmospheric Source

    International Nuclear Information System (INIS)

    Davis, P.A.; Kim, S.B.; Chouhan, S.L.; Workman, W.J.G.

    2005-01-01

    Tritium concentrations were measured in a large number of environmental and biological samples collected during 2002 at two dairy farms and a hobby farm near Pickering Nuclear Generating Station in Ontario, Canada. The data cover most compartments of the terrestrial food chain in an agricultural setting and include detailed information on the diets of the local farm animals. Ratios of plant OBT concentration to air moisture HTO varied between 0.12 and 0.56, and were generally higher for the forage crops collected at the dairy farms than for the garden vegetables sampled at the hobby farm. Animal OBT to air HTO ratios were more uniform, ranging from 0.18 to 0.45, and were generally higher for the milk and beef samples from the dairy farms than for the chicken products from the hobby farm. The observed OBT concentrations in plants and animals were compared with predictions of IMPACT, the model used by the Canadian nuclear industry to calculate annual average doses due to routine releases. The model performed well on average for the animal endpoints but overestimated concentrations in plants by a factor of 2

  8. Extraction as a source of additional information when concentrations in multicomponent systems are simultaneously determined

    International Nuclear Information System (INIS)

    Perkov, I.G.

    1988-01-01

    Using as an example photometric determination of Nd and Sm in their joint presence, the possibility to use the influence of extraction on analytic signal increase is considered. It is shown that interligand exchange in extracts in combination with simultaneous determination of concentrations can be used as a simple means increasing the accuracy of determination. 5 refs.; 2 figs.; 3 tabs

  9. Concentration, Source, and Potential Human Health Risk of Heavy Metals in the Commonly Consumed Medicinal Plants.

    Science.gov (United States)

    Kohzadi, Shadi; Shahmoradi, Behzad; Ghaderi, Ebrahim; Loqmani, Hozan; Maleki, Afshin

    2018-04-26

    A trend toward the use of traditional and herbal medicines has developed nowadays, and there is a growing concern regarding them being polluted with heavy metals. This study measured the heavy metal concentrations in eight different types of medicinal herbs and eight different types of herbal distillates sold in the markets in Sanandaj, Kurdistan, Iran. The concentration of some metals (Cd, Cu, Mn, Fe, Zn, Al, Co, Ni, Cr, Pb, and Mg) was quantified by inductively coupled plasma mass spectrometry, and the associated health risk for adults and children was estimated. The mean concentration of all the metals was within the permissible limits set by the WHO. The medicinal herbs contained significantly more Al, As, Cd, Cr, Fe, Mn, Ni, Pb, and Zn (p distillates. However, the concentrations of Cu and Hg were higher in the herbal distillates. The non-carcinogenic risks of consumption of traditional medicines in adults and children were assessed based on the target hazard quotients (THQs). The THQs for individual metals (except Al and Cr) from individual herbs were less than 1, which is considered as safe for human consumption.

  10. From source to surface: Tracking magmatic boron and chlorine input into the geothermal systems of the Taupo Volcanic Zone, New Zealand

    Science.gov (United States)

    Bégué, Florence; Deering, Chad D.; Gravley, Darren M.; Chambefort, Isabelle; Kennedy, Ben M.

    2017-10-01

    The magmatic contribution into geothermal fluids in the central Taupo Volcanic Zone (TVZ), New Zealand, has been attributed to either andesitic, 'arc-type' fluids, or rhyolitic, 'rift-type' fluids to explain the compositional diversity of discharge waters. However, this model relies on outdated assumptions related to geochemical trends associated with the magma at depth of typical arc to back-arc settings. Current tectonic models have shown that the TVZ is situated within a rifting arc and hosts magmatic systems dominated by distinct rhyolite types, that are likely to have evolved under different conditions than the subordinate andesites. Therefore, a new appraisal of the existing models is required to further understand the origin of the spatial compositional diversity observed in the geothermal fluids and its relationship to the structural setting. Here, we use volatile concentrations (i.e. H2O, Cl, B) from rhyolitic and andesitic mineral-hosted melt inclusions to evaluate the magmatic contribution to the TVZ geothermal systems. The andesite and two different types of rhyolites (R1 and R2) are each distinct in Cl/H2O and B/Cl, which will affect volatile solubility and phase separation (vapor vs. hydrosaline liquid) of the exsolved volatile phase. Ultimately, these key differences in the magmatic volatile constituents will play a significant role in governing the concentration of Cl discharged into geothermal systems. We estimate bulk fluid compositions (B and Cl) in equilibrium with the different melt types to show the potential contribution of 'parent' fluids to the geothermal systems throughout the TVZ. The results of this analysis show that the variability in fluid compositions partly reflects degassing from previously unaccounted for distinct magma source compositions. We suggest the geothermal systems that appear to have an 'arc-type' andesitic fluid contribution are actually derived from a rhyolite melt in equilibrium with a highly crystalline andesite

  11. Influence of nitrogen source and concentrations on wheat growth and production inside "Lunar Palace-1"

    Science.gov (United States)

    Dong, Chen; Chu, Zhengpei; Wang, Minjuan; Qin, Youcai; Yi, Zhihao; Liu, Hong; Fu, Yuming

    2018-03-01

    Minimizing nitrogen (N) consumption and maximizing crop productivity are major challenges to growing plants in Bioregenerative Life Support System (BLSS) for future long-term space mission. Plants cultivated in the controlled environments are sensitive to the low recyclable N (such as from the urine). The purpose of this study is to investigate the effects of nitrogen fertilizer (NH4+-N and NO3--N) disturbance on growth, photosynthetic efficiency, antioxidant defence systems and biomass yield and quality of wheat (Triticum aestivum L.) cultivars during ontogenesis. Experiments were divided into 4 controlled groups,Ⅰ: NO3--N: NH4+-N = 7:1 mmol L-1; Ⅱ: NO3--N: NH4+-N = 14:0.5 mmol L-1; Ⅲ: NO3--N: NH4+-N = 7:0.5 mmol L-1 and CK: NO3--N: NH4+-N = 14:1 mmol L-1, and other salt concentrations were the same. The results showed that heading and flowering stages in spring wheat are sensitive to low N concentration, especially NO3--N in group Ⅰ and Ⅲ. NO3- is better to root growth than to shoot growth. The plants were spindling and the output was lower 21.3% when spring wheat was in low N concentration solution. Meanwhile, photosynthetic rate of low N concentrations is worse than that of CK. The soluble sugar content of the edible part of wheat plants is influenced with NO3-: NH4+ ratio. In addition, when N concentration was lowest in group Ⅲ, the lignin content decreased to 2.58%, which was more beneficial to recycle substances in the processes of the environment regeneration.

  12. Fluoride concentrations in soils, vegetation samples and soil fauna in the direct vicinity of a pollution source

    International Nuclear Information System (INIS)

    Vogel, J.; Ottow, J.C.G.; Breimer, R.F.

    1989-01-01

    Fluoride analyses CF t = total F; F w = water soluble F and F HCI HCI-extractable F) of different soils, vegetation samples and soil fauna (Helix pomatia, Lumbricus spp., arthropodes) in a locally polluted area (for nearly 65 years) clearly revealed an F-accumulation in top soil, vegetation and animals. Based on 1N HCI-extractable fluoride, two contamination zones around the emitting industry could be identified. In the calcareous soils, leaching of fluoride seems to be insignificant because of a strong immobilization as CaF 2 . A highly significant correlation between the F HCI content of soils and Lumbricus spp. (with and without gut content) or Helix pomatia shells was found. Fluoride concentrations in washed leaves of Hedera helix and in decaying grass reached levels of 306 and 997 μgF/g respectively. Saprophagous soil arthropods contained high fluoride levels, up to 732 μgF/g in Armadillidium vulgare. (orig.)

  13. The Characteristics and Potential Source Area Analysis of PM2.5 Concentration for Zhengzhou during 2016

    Science.gov (United States)

    Li, D.; Liu, J.; Li, S.; Wang, C.; Zhou, S.

    2018-04-01

    This study used the HYSPLIT-4 model combined with cluster analysis, potential source pollution contribution functions and other methods to analyse the ground air pollution monitoring data and meteorological data in Zhengzhou during 2016. The results showed that: 1) the level of PM2.5 reached the low value in summer. The PM2.5 concentration reached the highest level in December and reached the lowest level in August. The daily variation characteristics of PM2.5 concentration in different seasons were roughly the same, and it had an obviously "double-peak" structure. 2) The annual PM2.5 concentration was positively correlated with atmospheric pressure and relative humidity. The annual PM2.5 concentration was negatively correlated with temperature, visibility, precipitation, and wind speed. 3) In winter, the air mass trajectory that through the northern Sichuan - Gansu - Shaanxi - Hubei was polluted seriously, and the level of PM2.5 was the highest which reached to 202.13 μg/m3. In summer, the air mass trajectory that came from Hubei was the lowest level with the value is 40.17 μg/m3. 4) The potential source areas located in northwest of Zhengzhou, Gansu, Hubei and Beijing-Tianjin-Hebei region in spring. The surrounding of Zhengzhou contributed to the pollution of Zhengzhou. The potential source areas appeared in Shaanxi, Sichuan, and Qinghai, the border between Ningxia and Inner Mongolia in autumn. In winter the potential source areas located in Jiangsu, Hubei, Henan, eastern of Shanxi, southern of Shanxi, Ningxia and the area of Yellow Sea, etc.

  14. Source, concentration, and distribution of elemental mercury in the atmosphere in Toronto, Canada

    International Nuclear Information System (INIS)

    Cairns, Elaine; Tharumakulasingam, Kavitharan; Athar, Makshoof; Yousaf, Muhammad; Cheng, Irene; Huang, Y.; Lu, Julia; Yap, Dave

    2011-01-01

    Atmospheric gaseous elemental mercury [GEM] at 1.8, 4, and 59 m above ground, in parking lots, and in indoor and outdoor air was measured in Toronto City, Canada from May 2008-July 2009. The average GEM value at 1.8 m was 1.89 ± 0.62 ng m -3 . The GEM values increased with elevation. The average GEM in underground parking lots ranged from 1.37 to 7.86 ng m -3 and was higher than those observed from the surface parking lots. The GEM in the indoor air ranged from 1.21 to 28.50 ng m -3 , was higher in the laboratories than in the offices, and was much higher than that in the outdoor air. All these indicate that buildings serve as sources of mercury to the urban atmosphere. More studies are needed to estimate the contribution of urban areas to the atmospheric mercury budget and the impact of indoor air on outdoor air quality and human health. - Highlights: → Buildings served as mercury sources to urban atmosphere. → Atmospheric mercury level increased with increasing height in the street canyon. → Emission from vehicles and ground surfaces was not the major sources of Hg to urban air. → Mercury levels were higher in indoor than outdoor air and in laboratories than in offices. → Mercury levels were higher in the outdoor air near building walls. - Buildings serve as sources of gaseous elemental mercury and research is needed to quantify the emission and to assess the impact of indoor air on outdoor air quality and human health.

  15. Sources Contributing to the Average Extracellular Concentration of Dopamine in the Nucleus Accumbens

    OpenAIRE

    Owesson-White, CA; Roitman, MF; Sombers, LA; Belle, AM; Keithley, RB; Peele, JL; Carelli, RM; Wightman, RM

    2012-01-01

    Mesolimbic dopamine neurons fire in both tonic and phasic modes resulting in detectable extracellular levels of dopamine in the nucleus accumbens (NAc). In the past, different techniques have targeted dopamine levels in the NAc to establish a basal concentration. In this study we used in vivo fast scan cyclic voltammetry (FSCV) in the NAc of awake, freely moving rats. The experiments were primarily designed to capture changes in dopamine due to phasic firing – that is, the measurement of dopa...

  16. Ambient concentrations and personal exposure to polycyclic aromatic hydrocarbons (PAH) in an urban community with mixed sources of air pollution

    Science.gov (United States)

    ZHU, XIANLEI; FAN, ZHIHUA (TINA); WU, XIANGMEI; JUNG, KYUNG HWA; OHMAN-STRICKLAND, PAMELA; BONANNO, LINDA J.; LIOY, PAUL J.

    2014-01-01

    Assessment of the health risks resulting from exposure to ambient polycyclic aromatic hydrocarbons (PAH) is limited by a lack of environmental exposure data among the general population. This study characterized personal exposure and ambient concentrations of PAH in the Village of Waterfront South (WFS), an urban community with many mixed sources of air toxics in Camden, New Jersey, and CopeWood/Davis Streets (CDS), an urban reference area located ~1 mile east of WFS. A total of 54 and 53 participants were recruited from non-smoking households in WFS and CDS, respectively. In all, 24-h personal and ambient air samples were collected simultaneously in both areas on weekdays and weekends during summer and winter. The ambient PAH concentrations in WFS were either significantly higher than or comparable to those in CDS, indicating the significant impact of local sources on PAH pollution in WFS. Analysis of diagnostic ratios and correlation suggested that diesel truck traffic, municipal waste combustion and industrial combustion were the major sources in WFS. In such an area, ambient air pollution contributed significantly to personal PAH exposure, explaining 44–96% of variability in personal concentrations. This study provides valuable data for examining the impact of local ambient PAH pollution on personal exposure and therefore potential health risks associated with environmental PAH pollution. PMID:21364704

  17. Concentration, distribution and source apportionment of atmospheric polycyclic aromatic hydrocarbons in the southeast suburb of Beijing, China.

    Science.gov (United States)

    Zhang, Shucai; Zhang, Wei; Wang, Kaiyan; Shen, Yating; Hu, Lianwu; Wang, Xuejun

    2009-04-01

    Total suspended particle samples and gas phase samples were collected at three representative sampling sites in the southeastern suburb of Beijing from March 2005 to January 2006. The samples were analyzed for 16 US EPA priority PAHs using GC/MS. Concentrations of Sigma PAHs in particle and gas phases were 0.21-1.18 x 10(3) ng m(-3) and 9.5 x 10(2) ng-1.03 x 10(5) ng m(-3), respectively. PAH concentrations displayed seasonal variation in the order of winter>spring>autumn>summer for particle phase, and winter>autumn>summer>spring for gas phase. Partial correlation analysis indicates that PAH concentrations in particle phase are negatively correlated with temperature and positively correlated with air pollution index of SO(2). No significant correlation is observed between gas phase PAHs and the auxiliary parameters. Sources of PAH are identified through principal component analysis, and source contributions are estimated through multiple linear regression. Major sources of atmospheric PAHs in the study area include coal combustion, coke industry, vehicular emission and natural gas combustion.

  18. EFFECT OF NITROGEN SOURCE AND INITIAL SUGAR CONCENTRATION ON LACTIC ACID FERMENTATION OF PINEAPPLE WASTE USING L.DELBRUECKII

    Directory of Open Access Journals (Sweden)

    Abdullah Moch Busairi

    2012-02-01

    Full Text Available The liquid pineapple waste contains mainly sucrose, glucose, fructose and other nutrients. It therefore can potentially be used as carbon source for lactic acid fermentation. The lactic acid is utilised in food technology as pH regulator, microbial preservative, buffering agent and in the chemical industry. Recently, lactic acid has been considered to be an important raw material for production of biodegradable lactate polymer. The experiments were carried out in batch fermentation at anaerobic condition with stirring speed: 50 rpm, temperature: 40 oC, pH: 6.0, and inoculum size: 5%. Effect of nitrogen source and initial sugar concentration were studied. The effect of nitrogen source on lactic acid production shows that the yeast extract is highest yield , followed by urea , corn steep liquor, malt sprout and ammonium sulphates with the yield of 78.52; 26.68; 19.14; 14.10 and 5.6 %, respectively. The highest yield of initial sugar concentration on lactic acid production obtained was 78.52 % (54.97 g/l at 70 g/l, if the concentration of sugar was increased to 110 g/l , the lactic acid production or yield decrease to51.53 g/l or 54.24%.

  19. Mass concentration, composition and sources of fine and coarse particulate matter in Tijuana, Mexico, during Cal-Mex campaign

    Science.gov (United States)

    Minguillón, María Cruz; Campos, Arturo Alberto; Cárdenas, Beatriz; Blanco, Salvador; Molina, Luisa T.; Querol, Xavier

    2014-05-01

    This work was carried out in the framework of the Cal-Mex project, which focuses on investigating the atmosphere along Mexico-California border region. Sampling was carried out at two sites located in Tijuana urban area: Parque Morelos and Metales y Derivados. PM2.5 and PM10 24 h samples were collected every three days from 17th May 2010 to 27th June 2010, and were used for gravimetric and chemical analyses (major and minor elements, inorganic ions, organic and elemental carbon) of PM. A subsequent Positive Matrix Factorization (PMF) analysis was performed. PM2.5 and PM10 average concentrations during Cal-Mex were relatively lower compared to usual annual averages. Trace elements concentrations recorded in the present study were lower than those recorded in Mexico City in 2006, with the exception of Pb at Metales y Derivados, attributed to the influence of a specific industrial source, which also includes As, Cd and Tl. Apart from this industrial source, both urban sites were found to be affected by similar sources with respect to bulk PM. Fine PM (PM2.5) was mainly apportioned by fueloil and biomass combustion and secondary aerosols, and road traffic. Coarse PM (PM2.5-10) was mainly apportioned by a mineral source (sum of road dust resuspension, construction emissions and natural soil) and fresh and aged sea salt. The road traffic was responsible for more than 60% of the fine elemental carbon and almost 40% of the fine organic matter.

  20. Radiation protection zoning

    International Nuclear Information System (INIS)

    2015-01-01

    Radiation being not visible, the zoning of an area containing radioactive sources is important in terms of safety. Concerning radiation protection, 2 work zones are defined by regulations: the monitored zone and the controlled zone. The ministerial order of 15 may 2006 settles the frontier between the 2 zones in terms of radiation dose rates, the rules for access and the safety standards in both zones. Radioprotection rules and the name of the person responsible for radiation protection must be displayed. The frontier between the 2 zones must be materialized and marked with adequate equipment (specific danger signs and tapes). Both zones are submitted to selective entrance, the access for the controlled zone is limited because of the radiation risk and of the necessity of confining radioactive contamination while the limitation of the access to the monitored zone is due to radiation risk only. (A.C.)

  1. Atmospheric concentrations, sources and gas-particle partitioning of PAHs in Beijing after the 29th Olympic Games

    Energy Technology Data Exchange (ETDEWEB)

    Ma Wanli [International Joint Research Center for Persistent Toxic Substances (IJRC-PTS), State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Sun Dezhi [International Joint Research Center for Persistent Toxic Substances (IJRC-PTS), State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083 (China); Shen Weiguo [College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083 (China); Yang Meng [IJRC-PTS, Dalian Maritime University, Dalian (China); Qi Hong; Liu Liyan; Shen Jimin [International Joint Research Center for Persistent Toxic Substances (IJRC-PTS), State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Li Yifan, E-mail: ijrc_pts_paper@yahoo.com [International Joint Research Center for Persistent Toxic Substances (IJRC-PTS), State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Science and Technology Branch, Environment Canada, Toronto, Ontario M3H5T4 (Canada)

    2011-07-15

    A comprehensive sampling campaign was carried out to study atmospheric concentration of polycyclic aromatic hydrocarbons (PAHs) in Beijing and to evaluate the effectiveness of source control strategies in reducing PAHs pollution after the 29th Olympic Games. The sub-cooled liquid vapor pressure (logP{sub L}{sup o})-based model and octanol-air partition coefficient (K{sub oa})-based model were applied based on each seasonal dateset. Regression analysis among log K{sub P}, logP{sub L}{sup o} and log K{sub oa} exhibited high significant correlations for four seasons. Source factors were identified by principle component analysis and contributions were further estimated by multiple linear regression. Pyrogenic sources and coke oven emission were identified as major sources for both the non-heating and heating seasons. As compared with literatures, the mean PAH concentrations before and after the 29th Olympic Games were reduced by more than 60%, indicating that the source control measures were effective for reducing PAHs pollution in Beijing. - Highlights: > This is the first comprehensive study of PAHs in atmosphere after the 29th Olympics in Beijing, China. > The air quality before and after 29th Olympics has attracted much attention worldwide. > The study was helpful for other countries to understand how the Olympics affected PAHs emissions. > The study would act as a case study to know the effects that big events can impose on the host cities. - The source control measures implemented before and during the 29th Olympic Games were effective for reducing the emissions of air pollutants in Beijing.

  2. Importance of data comparability for multi-year trends and source apportionment of NMHC concentrations observed in France

    Science.gov (United States)

    Sauvage, Stéphane; Waked, Antoine; Leonardis, Thierry; Locoge, Nadine

    2017-04-01

    Non Methane Hydrocarbon Compounds (NMHCs) are of interest due to their potential health impact and their key role in atmospheric processes as precursors of secondary pollutants such as ozone (O3) and secondary organic aerosols (SOA). Hourly measurements of 31 non-methane hydrocarbons (NMHCs) were carried out at three urban sites in France over the period of a decade. The trends analysis showed a significant yearly decrease in pollutant concentrations over the study period and for the majority of species in the range of -1 to -7% in accordance with the decrease of NMHC emissions in France (-5 to -9%). Concentrations of long-lived species such as ethane and propane which are known as tracers of distant sources and natural gas remained constant. These trends are consistent with those recently described at urban and background sites in the northern mid-latitudes and with emission inventories. They are compared with the ones reported for 3 French rural sites (EMEP). A year per year source apportionment study using PMF was also conducted for 2 of the urban sites over the period 2005-2013. Using source fingerprints, five common anthropogenic sources were identified for Paris and Strasbourg: traffic-exhaust emissions (21±5%, 18±5%), evaporative sources (17±4%, 24±7%), natural gas & background (22±5%, 25±5%), residential heating (17±4%, 17±5%) and solvent use (19±7%, 12±5%). Biogenic sources were also identified and accounted for 4±1% of the total measured NMHC's at both sites. Along the presentation, the robustness of these results will be discussed regarding the site representativeness, the data comparability, and the temporal variation of the data quality

  3. A summary of total mercury concentrations in flora and fauna near common contaminant sources in the Gulf of Mexico.

    Science.gov (United States)

    Lewis, M; Chancy, C

    2008-02-01

    Total mercury concentrations are summarized for environmental media and biota collected from near-coastal areas, several impacted by contaminant sources common to the Gulf of Mexico. Water, sediment, fish, blue crabs, oysters, clams, mussels, periphyton and seagrasses were collected during 1993-2002 from targeted areas affected by point and non-point source contaminants. Mean concentrations in water and sediment were 0.02 (+/-1 standard deviation=0.06) microg l(-1) and 96.3 (230.8) ng g(-1) dry wt, respectively. Mean total mercury concentrations in fish, blue crabs, brackish clams and mussels were significantly greater than those in sediment, seagrass, colonized periphyton and oysters. Concentrations (ng g(-1) dry wt) averaged 23.1 (two seagrass species), 220.1 (oysters), 287.8 (colonized periphyton), 604.0 (four species of freshwater mussels), 772.4 (brackish clam), 857.9 (blue crabs) and 933.1 (nine fish species). Spatial, intraspecific and interspecific variability in results limited most generalizations concerning the relative mercury contributions of different stressor types. However, concentrations were significantly greater for some biota collected from areas receiving wastewater discharges and golf course runoff (fish), agricultural runoff (oysters) and urban stormwater runoff (colonized periphyton and sediment). Marine water quality criteria and proposed sediment quality guidelines were exceeded in 1-12% of total samples. At least one seafood consumption guideline, criteria or screening value were exceeded in edible tissues of blue crabs (6% total samples) and nine fish species (8-33% total samples) but all residues were less than the US Federal Drug Administration action limit of 1.0 ppm and the few reported toxic effect concentrations available for the targeted biota.

  4. PM4 crystalline silica emission factors and ambient concentrations at aggregate-producing sources in California.

    Science.gov (United States)

    Richards, John R; Brozell, Todd T; Rea, Charles; Boraston, Geoff; Hayden, John

    2009-11-01

    The California Construction and Industrial Minerals Association and the National Stone, Sand, & Gravel Association have sponsored tests at three sand and gravel plants in California to compile crystalline silica emission factors for particulate matter (PM) of aerodynamic diameter of 4 microm or less (PM4) and ambient concentration data. This information is needed by industrial facilities to evaluate compliance with the Chronic Reference Exposure Level (REL) for ambient crystalline silica adopted in 2005 by the California Office of Environmental Health Hazard Assessment. The REL applies to PM4 respirable PM. Air Control Techniques, P.C. sampled for PM4 crystalline silica using a conventional sampler for PM of aerodynamic diameter of 2.5 microm or less (PM2.5), which met the requirements of 40 Code of Federal Regulations Part 50, Appendix L. The sample flow rate was adjusted to modify the 50% cut size to 4 microm instead of 2.5 microm. The filter was also changed to allow for crystalline silica analyses using National Institute for Occupational Safety and Health (NIOSH) Method 7500. The particle size-capture efficiency curve for the modified Appendix L instrument closely matched the performance curve of NIOSH Method 0600 for PM4 crystalline silica and provided a minimum detection limit well below the levels attainable with NIOSH Method 0600. The results of the tests indicate that PM4 crystalline silica emissions range from 0.000006 to 0.000110 lb/t for screening operations, tertiary crushers, and conveyor transfer points. The PM4 crystalline silica emission factors were proportional to the crystalline silica content of the material handled in the process equipment. Measured ambient concentrations ranged from 0 (below detectable limit) to 2.8 microg/m3. All values measured above 2 microg/m3 were at locations upwind of the facilities being tested. The ambient PM4 crystalline silica concentrations measured during this study were below the California REL of 3 microg/m3

  5. A source of ground water 222Rn around Tachikawa fault

    International Nuclear Information System (INIS)

    Saito, Masaaki; Takata, Sigeru

    1994-01-01

    Radon ( 222 Rn) concentration in ground water was characteristically high on the south-western zone divided by the Tachikawa fault, Tokyo. (1) The concentration did not increase with depth, and alluvium is thick on the zone. The source of radon was not considered as the updraft from base rock through the fault. Comparing the south-western zone with its surrounding zone, the followings were found. (2) The distribution of tritium concentration was supported that water had easily permeated into ground on the zone. (3) As the zone is located beside the Tama River and its alluvial fan center, the river water had likely affected. The source of radon on the zone would be 226 Ra in the aquifer soil. It can be presumed that the water of the Tama River had permeated into ground on the zone and had accumulated 226 Ra. (author)

  6. Exploring the uncertainty in attributing sediment contributions in fingerprinting studies due to uncertainty in determining element concentrations in source areas.

    Science.gov (United States)

    Gomez, Jose Alfonso; Owens, Phillip N.; Koiter, Alex J.; Lobb, David

    2016-04-01

    One of the major sources of uncertainty in attributing sediment sources in fingerprinting studies is the uncertainty in determining the concentrations of the elements used in the mixing model due to the variability of the concentrations of these elements in the source materials (e.g., Kraushaar et al., 2015). The uncertainty in determining the "true" concentration of a given element in each one of the source areas depends on several factors, among them the spatial variability of that element, the sampling procedure and sampling density. Researchers have limited control over these factors, and usually sampling density tends to be sparse, limited by time and the resources available. Monte Carlo analysis has been used regularly in fingerprinting studies to explore the probable solutions within the measured variability of the elements in the source areas, providing an appraisal of the probability of the different solutions (e.g., Collins et al., 2012). This problem can be considered analogous to the propagation of uncertainty in hydrologic models due to uncertainty in the determination of the values of the model parameters, and there are many examples of Monte Carlo analysis of this uncertainty (e.g., Freeze, 1980; Gómez et al., 2001). Some of these model analyses rely on the simulation of "virtual" situations that were calibrated from parameter values found in the literature, with the purpose of providing insight about the response of the model to different configurations of input parameters. This approach - evaluating the answer for a "virtual" problem whose solution could be known in advance - might be useful in evaluating the propagation of uncertainty in mixing models in sediment fingerprinting studies. In this communication, we present the preliminary results of an on-going study evaluating the effect of variability of element concentrations in source materials, sampling density, and the number of elements included in the mixing models. For this study a virtual

  7. Rising atmospheric CO2 is reducing the protein concentration of a floral pollen source essential for North American bees.

    Science.gov (United States)

    Ziska, Lewis H; Pettis, Jeffery S; Edwards, Joan; Hancock, Jillian E; Tomecek, Martha B; Clark, Andrew; Dukes, Jeffrey S; Loladze, Irakli; Polley, H Wayne

    2016-04-13

    At present, there is substantive evidence that the nutritional content of agriculturally important food crops will decrease in response to rising levels of atmospheric carbon dioxide, Ca However, whether Ca-induced declines in nutritional quality are also occurring for pollinator food sources is unknown. Flowering late in the season, goldenrod (Solidago spp.) pollen is a widely available autumnal food source commonly acknowledged by apiarists to be essential to native bee (e.g. Bombus spp.) and honeybee (Apis mellifera) health and winter survival. Using floral collections obtained from the Smithsonian Natural History Museum, we quantified Ca-induced temporal changes in pollen protein concentration of Canada goldenrod (Solidago canadensis), the most wide spread Solidago taxon, from hundreds of samples collected throughout the USA and southern Canada over the period 1842-2014 (i.e. a Ca from approx. 280 to 398 ppm). In addition, we conducted a 2 year in situtrial of S. Canadensis populations grown along a continuous Ca gradient from approximately 280 to 500 ppm. The historical data indicated a strong significant correlation between recent increases in Ca and reductions in pollen protein concentration (r(2)= 0.81). Experimental data confirmed this decrease in pollen protein concentration, and indicated that it would be ongoing as Ca continues to rise in the near term, i.e. to 500 ppm (r(2)= 0.88). While additional data are needed to quantify the subsequent effects of reduced protein concentration for Canada goldenrod on bee health and population stability, these results are the first to indicate that increasing Ca can reduce protein content of a floral pollen source widely used by North American bees. © 2016 The Author(s).

  8. Sources of ambient concentrations and chemical composition of PM 2.5-0.1 in Cork Harbour, Ireland

    Science.gov (United States)

    Hellebust, S.; Allanic, A.; O'Connor, I. P.; Jourdan, C.; Healy, D.; Sodeau, J. R.

    2010-02-01

    Particulate matter (PM 10-2.5 and PM 2.5-0.1) has been collected over a period of one year in Cork Harbour, Ireland, using a high-volume cascade impactor and polyurethane foam collection substrate. Collected PM 2.5-0.1 was analysed for water-soluble inorganic ions and metal content using ion chromatography and inductively coupled plasma-optical emission spectroscopy. On average approximately 50% by mass of the chemical content of PM was identified. The motivation for the study was to assess the potential impact of shipping emissions on air quality in Cork Harbour and City, with a view to informing public health impacts. The average ambient concentration of PM 10 between May 2007 and April 2008 was 4.6 µgm - 3 and the maximum concentration measured in one sample, representing a 4 day collection period, was 16 µgm - 3 . The major inorganic constituents identified in PM collected in Haulbowline Island in Cork Harbour were sulfate, ammonium, nitrate, chloride and sodium ions, which were mainly attributable to sea salt and secondary inorganic aerosols from regional sources. The results were analysed by principal component analysis for the purpose of source apportionment. Four factors were identified explaining over 80% of the data set variance. The factors were: shipping, sea salt, crustal material and secondary inorganic aerosols (SIA). The smaller size fraction was frequently observed to dominate, as the average concentration was 2.77 µgm - 3 for PM 2.5-0.1 compared to 1.9 µgm - 3 for PM 10-2.5. Fresh ship plumes were not found to make a significant contribution to primary PM 2.5-0.1 concentrations adjacent to the shipping channel. However, this was partially attributed to the ultrafine nature of ship emissions and the majority of the toxic metal content was attributed to emissions associated with heavy oil combustion sources, which include ship engines.

  9. Estimation of unsaturated zone traveltimes for Rainier Mesa and Shoshone Mountain, Nevada Test Site, Nevada, using a source-responsive preferential-flow model

    Energy Technology Data Exchange (ETDEWEB)

    Brian A. Ebel; John R. Nimmo

    2009-09-11

    unsaturated zone takes place as preferential flow, faster than would be predicted by the coupled Richards' and advection-dispersion equations with hydraulic properties estimated by traditional means. At present the hydrologic community has not achieved consensus as to whether a modification of Richards' equation, or a fundamentally different formulation, would best quantify preferential flow. Where the fastest contaminant transport speed is what needs to be estimated, there is the possibility of simplification of the evaluation process. One way of doing so is by a two-step process in which the first step is to evaluate whether significant preferential flow and solute transport is possible for the media and conditions of concern. The second step is to carry out (a) a basic Richards' and advection-dispersion equation analysis if it is concluded that preferential flow is not possible or (b) an analysis that considers only the fastest possible preferential-flow processes, if preferential flow is possible. For the preferential-flow situation, a recently published model describable as a Source-Responsive Preferential-Flow (SRPF) model is an easily applied option. This report documents the application of this two-step process to flow through the thick unsaturated zones of Rainier Mesa and Shoshone Mountain in the Nevada Test Site. Application of the SRPF model involves distinguishing between continuous and intermittent water supply to preferential flow paths. At Rainier Mesa and Shoshone Mountain this issue is complicated by the fact that contaminant travel begins at a location deep in the subsurface, where there may be perched water that may or may not act like a continuous supply, depending on such features as the connectedness of fractures and the nature of impeding layers. We have treated this situation by hypothesizing both continuous and intermittent scenarios for contaminant transport to the carbonate aquifer and reporting estimation of the fastest speed for

  10. Estimation of Unsaturated Zone Traveltimes for Rainier Mesa and Shoshone Mountain, Nevada Test Site, Nevada, Using a Source-Responsive Preferential-Flow Model

    Science.gov (United States)

    Ebel, Brian A.; Nimmo, John R.

    2009-01-01

    zone takes place as preferential flow, faster than would be predicted by the coupled Richards' and advection-dispersion equations with hydraulic properties estimated by traditional means. At present the hydrologic community has not achieved consensus as to whether a modification of Richards' equation, or a fundamentally different formulation, would best quantify preferential flow. Where the fastest contaminant transport speed is what needs to be estimated, there is the possibility of simplification of the evaluation process. One way of doing so is by a two-step process in which the first step is to evaluate whether significant preferential flow and solute transport is possible for the media and conditions of concern. The second step is to carry out (a) a basic Richards' and advection-dispersion equation analysis if it is concluded that preferential flow is not possible or (b) an analysis that considers only the fastest possible preferential-flow processes, if preferential flow is possible. For the preferential-flow situation, a recently published model describable as a Source-Responsive Preferential-Flow (SRPF) model is an easily applied option. This report documents the application of this two-step process to flow through the thick unsaturated zones of Rainier Mesa and Shoshone Mountain in the Nevada Test Site. Application of the SRPF model involves distinguishing between continuous and intermittent water supply to preferential flow paths. At Rainier Mesa and Shoshone Mountain this issue is complicated by the fact that contaminant travel begins at a location deep in the subsurface, where there may be perched water that may or may not act like a continuous supply, depending on such features as the connectedness of fractures and the nature of impeding layers. We have treated this situation by hypothesizing both continuous and intermittent scenarios for contaminant transport to the carbonate aquifer and reporting estimation of the fastest speed for both of th

  11. Concentrations, distribution, sources and risk assessment of organohalogenated contaminants in soils from Kenya, Eastern Africa

    International Nuclear Information System (INIS)

    Sun, Hongwei; Qi, Yueling; Zhang, Di; Li, Qing X.; Wang, Jun

    2016-01-01

    The organohalogenated contaminants (OCs) including 12 organochlorine pesticides (OCPs), 7 indicator polychlorinated biphenyls (PCBs) and 7 polybrominated diphenyl ethers (PBDEs) were determined in soils collected from Kenya, Eastern Africa. The total OCPs fell in the range of n.d–49.74 μg kg"−"1 dry weight (dw), which was dominated by DDTs and endosulfan. Identification of pollution sources indicated new input of DDTs for malaria control in Kenya. The total PCBs ranged from n.d. to 55.49 μg kg"−"1 dw, dominated by penta- and hexa-PCBs, probably associated with the leakage of obsolete transformer oil. The soils were less contaminated by PBDEs, ranging from 0.19 to 35.64 μg kg"−"1 dw. The predominant PBDE congeners were penta-, tri- or tetra-BDEs, varying among different sampling sites. Risk assessment indicated potential human health risks posed by OCs in soils from Kenya, with PCBs as the most contributing pollutants. The local authorities are recommended to make best efforts on management of OC pollution, particularly from DDTs and PCBs to meet the requirement of Stockholm Convention. - Highlights: • The first report on organohalogen contaminants (OCs) in soils from Kenya. • OCs including OCPs, PCBs and PBDEs were determined simultaneously. • Sources of OCPs, PCBs and PBDEs emission were identified. • Human health risk posed by OCs in soil from Kenya were assessed. • Measures for OCs management were suggested for local authority. - The soils from Kenya were heavily polluted by organohalogenated contaminants (OCs). New input of DDTs probably occurred. Among all OCs, PCBs were predominant.

  12. Transient reaction of an elastic half-plane on a source of a concentrated boundary disturbance

    Science.gov (United States)

    Okonechnikov, A. S.; Tarlakovski, D. V.; Ul'yashina, A. N.; Fedotenkov, G. V.

    2016-11-01

    One of the key problems in studying the non-stationary processes of solid mechanics is obtaining of influence functions. These functions serve as solutions for the problems of effect of sudden concentrated loads on a body with linear elastic properties. Knowledge of the influence functions allows us to obtain the solutions for the problems with non-mixed boundary and initial conditions in the form of quadrature formulae with the help of superposition principle, as well as get the integral governing equations for the problems with mixed boundary and initial conditions. This paper offers explicit derivations for all nonstationary surface influence functions of an elastic half-plane in a plane strain condition. It is achieved with the help of combined inverse transform of a Fourier-Laplace integral transformation. The external disturbance is both dynamic and kinematic. The derived functions in xτ-domain are studied to find and describe singularities and are supplemented with graphs.

  13. Thermosolutal convection in saturated porous enclosure with concentrated energy and solute sources

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Di; Zhao, Fu-Yun; Tang, Guang-Fa [College of Civil Engineering, Hunan University, Changsha (China)

    2008-01-15

    Double diffusive natural convection within a vertical porous enclosure with localized heating and salting from one side is numerically studied by the finite element based finite volume method. In the formulation of the problem, use is made of the Darcy model, which allows the slip boundary condition on a solid wall to be satisfied. Comparisons with benchmark solutions for natural convection in fluid saturated porous enclosures are first presented to validate the code. Following that, an extensive series of numerical simulations is conducted in the range of -55 {<=} N {<=} + 55 and 0.125 {<=} L {<=} 0.875, where N and L are the buoyancy ratio and the element location, respectively. Streamlines, heatlines, masslines, isotherms and iso-concentrations in the system are produced to illustrate the flow structure transition from solutal dominated opposing to thermal dominated and solutal dominated aiding flows, respectively. The computed average Nusselt and Sherwood numbers provide guidance for locating the heating and salting element. (author)

  14. Thermosolutal convection in saturated porous enclosure with concentrated energy and solute sources

    Energy Technology Data Exchange (ETDEWEB)

    Liu Di [College of Civil Engineering, Hunan University, Changsha (China)], E-mail: liudi66@163.com; Zhao Fuyun [College of Civil Engineering, Hunan University, Changsha (China)], E-mail: zfycfdnet@163.com; Tang Guangfa [College of Civil Engineering, Hunan University, Changsha (China)], E-mail: gftangcfd@163.com

    2008-01-15

    Double diffusive natural convection within a vertical porous enclosure with localized heating and salting from one side is numerically studied by the finite element based finite volume method. In the formulation of the problem, use is made of the Darcy model, which allows the slip boundary condition on a solid wall to be satisfied. Comparisons with benchmark solutions for natural convection in fluid saturated porous enclosures are first presented to validate the code. Following that, an extensive series of numerical simulations is conducted in the range of -55 {<=} N {<=} + 55 and 0.125 {<=} L {<=} 0.875, where N and L are the buoyancy ratio and the element location, respectively. Streamlines, heatlines, masslines, isotherms and iso-concentrations in the system are produced to illustrate the flow structure transition from solutal dominated opposing to thermal dominated and solutal dominated aiding flows, respectively. The computed average Nusselt and Sherwood numbers provide guidance for locating the heating and salting element.

  15. Dynamics of suspended sediment concentration, flow discharge and sediment particle size interdependency to identify sediment source

    Science.gov (United States)

    Sadeghi, Seyed Hamidreza; Singh, Vijay P.

    2017-11-01

    Spatiotemporal behavior of sediment yield is a key for proper watershed management. This study analyzed statistical characteristics and trends of suspended sediment concentration (SCS), flow discharge (FD) and sediment particle sizes using data from 24 gage stations scattered throughout the United States. Analysis showed significant time- and location-specific differences of these variables. The median values of SSC, FD and percentage of particle sizes smaller than 63 μm (P63) for all 24 gage stations were found to be 510.236 mg l-1 (right skewed), 45.406 m3 s-1 (left skewed) and 78.648% (right skewed), respectively. Most of the stations exhibited significant trends (P practices which may call for local or regional planning based on natural (i.e., precipitation amount, type and erosivity, watershed area, and soil erodibility) and human-affected (i.e., land use and hydraulic structures and water resources management) factors governing the study variables.

  16. Submicron particle mass concentrations and sources in the Amazonian wet season (AMAZE-08)

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Q.; Farmer, D. K.; Rizzo, L. V.; Pauliqueivis, T.; Kuwata, Mikinori; Karl, Thomas G.; Guenther, Alex B.; Allan, James D.; Coe, H.; Andreae, M. O.; Poeschl, U.; Jiminez, J. L.; Artaxo, Paulo; Martin, Scot T.

    2015-01-01

    Real-time mass spectra of non-refractory component of submicron aerosol particles were recorded in a tropical rainforest in the central Amazon basin during the wet season of 2008, as a part of the Amazonian Aerosol Characterization Experiment (AMAZE-08). Organic components accounted on average for more than 80% of the non-refractory submicron particle mass concentrations during the period of measurements. Ammonium was present in sufficient quantities to halfway neutralize sulfate. In this acidic, isoprene-dominated, low-NOx environment the high-resolution mass spectra as well as mass closures with ion chromatography measurements did not provide evidence for significant contributions of organosulfate species, at least at concentrations above uncertainty levels. Positive-matrix factorization of the time series of particle mass spectra identified four statistical factors to account for the variance of the signal intensities of the organic constituents: a factor HOA having a hydrocarbon-like signature and identified as regional emissions of primary organic material, a factor OOA-1 associated with fresh production of secondary organic material by a mechanism of BVOC oxidation followed by gas-to-particle conversion, a factor OOA-2 consistent with reactive uptake of isoprene oxidation products, especially epoxydiols by acidic particles, and a factor OOA-3 associated with long range transport and atmospheric aging. The OOA-1, -2, and -3 factors had progressively more oxidized signatures. Diameter-resolved mass spectral markers also suggested enhanced reactive uptake of isoprene oxidation products to the accumulation mode for the OOA-2 factor, and such size partitioning can be indicative of in-cloud process. The campaign-average factor loadings were in a ratio of 1.1:1.0 for the OOA-1 compared to the OOA-2 pathway, suggesting the comparable importance of gas-phase compared to particle-phase (including cloud waters) production pathways of secondary organic material during

  17. Measurements of soil, surface water, and groundwater CO2 concentration variability within Earth's critical zone: low-cost, long-term, high-temporal resolution monitoring

    Science.gov (United States)

    Blackstock, J. M.; Covington, M. D.; Williams, S. G. W.; Myre, J. M.; Rodriguez, J.

    2017-12-01

    Variability in CO2 fluxes within Earth's Critical zone occurs over a wide range of timescales. Resolving this and its drivers requires high-temporal resolution monitoring of CO2 both in the soil and aquatic environments. High-cost (> 1,000 USD) gas analyzers and data loggers present cost-barriers for investigations with limited budgets, particularly if high spatial resolution is desired. To overcome high-costs, we developed an Arduino based CO2 measuring platform (i.e. gas analyzer and data logger). The platform was deployed at multiple sites within the Critical Zone overlying the Springfield Plateau aquifer in Northwest Arkansas, USA. The CO2 gas analyzer used in this study was a relatively low-cost SenseAir K30. The analyzer's optical housing was covered by a PTFE semi-permeable membrane allowing for gas exchange between the analyzer and environment. Total approximate cost of the monitoring platform was 200 USD (2% detection limit) to 300 USD (10% detection limit) depending on the K30 model used. For testing purposes, we deployed the Arduino based platform alongside a commercial monitoring platform. CO2 concentration time series were nearly identical. Notably, CO2 cycles at the surface water site, which operated from January to April 2017, displayed a systematic increase in daily CO2 amplitude. Preliminary interpretation suggests key observation of seasonally increasing stream metabolic function. Other interpretations of observed cyclical and event-based behavior are out of the scope of the study; however, the presented method describes an accurate near-hourly characterization of CO2 variability. The new platform has been shown to be operational for several months, and we infer reliable operation for much longer deployments (> 1 year) given adequate environmental protection and power supply. Considering cost-savings, this platform is an attractive option for continuous, accurate, low-power, and low-cost CO2 monitoring for remote locations, globally.

  18. Observations of fine particulate nitrated phenols in four sites in northern China: concentrations, source apportionment, and secondary formation

    Science.gov (United States)

    Wang, Liwei; Wang, Xinfeng; Gu, Rongrong; Wang, Hao; Yao, Lan; Wen, Liang; Zhu, Fanping; Wang, Weihao; Xue, Likun; Yang, Lingxiao; Lu, Keding; Chen, Jianmin; Wang, Tao; Zhang, Yuanghang; Wang, Wenxing

    2018-03-01

    Filter samples of fine particulate matters were collected at four sites in northern China (urban, rural, and mountain) in summer and winter, and the contents of nine nitrated phenols were quantified in the laboratory with the use of ultra-high-performance liquid chromatography coupled with mass spectrometry. During the sampling periods, the concentrations of particulate nitrated phenols exhibited distinct temporal and spatial variation. On average, the total concentration of particulate nitrated phenols in urban Jinan in the wintertime reached 48.4 ng m-3, and those in the summertime were 9.8, 5.7, 5.9, and 2.5 ng m-3 in urban Jinan, rural Yucheng and Wangdu, and Mt. Tai, respectively. The elevated concentrations of nitrated phenols in wintertime and in urban areas demonstrate the apparent influences of anthropogenic sources. The positive matrix factorization receptor model was then applied to determine the origins of particulate nitrated phenols in northern China. The five major source factors were traffic, coal combustion, biomass burning, secondary formation, and aged coal combustion plume. Among them, coal combustion played a vital role, especially at the urban site in the wintertime, with a contribution of around 55 %. In the summertime, the observed nitrated phenols were highly influenced by aged coal combustion plumes at all of the sampling sites. Meanwhile, in remote areas, contributions from secondary formation were significant. Further correlation analysis indicates that nitrosalicylic acids were produced mostly from secondary formation that was dominated by NO2 nitration.

  19. The effect of cation source and dietary cation-anion difference on rumen ion concentrations in lactating dairy cows.

    Science.gov (United States)

    Catterton, T L; Erdman, R A

    2016-08-01

    Many studies have focused on the influence of dietary cation-anion difference (DCAD) on animal performance but few have examined the effect of DCAD on the rumen ionic environment. The objective of this study was to examine the effects of DCAD, cation source (Na vs. K), and anion source (Cl vs. bicarbonate or carbonate) on rumen environment and fermentation. The study used 5 rumen-fistulated dairy cows and 5 dietary treatments that were applied using a 5×5 Latin square design with 2-wk experimental periods. Treatments consisted of (1) the basal total mixed ration (TMR); (2) the basal TMR plus 340mEq/kg of Na (dry matter basis) using NaCl; (3) the basal TMR plus 340mEq/kg of K using KCl; (4) the basal TMR plus 340mEq/kg of Na using NaHCO3; and (5) the basal TMR plus 340mEq/kg of K using K2CO3. On the last day of each experimental period, rumen samples were collected and pooled from 5 different locations at 0, 1.5, 3, 4.5, 6, 9, and 12h postfeeding for measurement of rumen pH and concentrations of strong ions and volatile fatty acids (VFA). Dietary supplementation of individual strong ions increased the corresponding rumen ion concentration. Rumen Na was decreased by 24mEq/L when K was substituted for Na in the diet, but added dietary Na had no effect on rumen K. Rumen Cl was increased by 10mEq/L in diets supplemented with Cl. Cation source had no effect on rumen pH or total VFA concentration. Increased DCAD increased rumen pH by 0.10 pH units and increased rumen acetate by 4mEq/L but did not increase total VFA. This study demonstrated that rumen ion concentrations can be manipulated by dietary ion concentrations. If production and feed efficiency responses to DCAD and ionophores in the diet are affected by rumen Na and K concentrations, then manipulating dietary Na and K could be used either to enhance or diminish those responses. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  20. Loss concentration and evacuation by mini-wire-septa from circular machines for spallation neutron sources

    CERN Document Server

    Schönauer, Horst Otto

    1996-01-01

    Efficient loss management is crucial in high-intensity circular machines like neutron sources, and those using superconducting magnets. Collimator systems have been designed or are under intensive study [1]. The common problem of collimation is the outscattering from the collimator faces which are most frequently hit at shallow depth. In this situation high collection efficiency can only be achieved by two-or-more-stage, double-jaw, systems requiring betatron phase advances approaching 2p. As the outscattering is isotropic, both transverse planes are affected and the system layout becomes a two-dimensional problem. Any convincing single-stage collimation system would be simpler to operate and is likely to be less expensive. The possible physical evacuation of the lost beam towards a remote dump can drastically reduce the radioactivity level in the tunnel. Moreover, fitting a two-stage system into an existing machine is difficult and in general not very promising. In this situation a wire septum may be the onl...

  1. Effectiveness of low emission zones: large scale analysis of changes in environmental NO2, NO and NOx concentrations in 17 German cities.

    Directory of Open Access Journals (Sweden)

    Peter Morfeld

    Full Text Available Low Emission Zones (LEZs are areas where the most polluting vehicles are restricted from entering. The effectiveness of LEZs to lower ambient exposures is under debate. This study focused on LEZs that restricted cars of Euro 1 standard without appropriate retrofitting systems from entering and estimated LEZ effects on NO2, NO, and NOx ( = NO2+NO.Continuous half-hour and diffuse sampler 4-week average NO2, NO, and NOx concentrations measured inside and outside LEZs in 17 German cities of 6 federal states (2005-2009 were analysed as matched quadruplets (two pairs of simultaneously measured index values inside LEZ and reference values outside LEZ, one pair measured before and one after introducing LEZs with time differences that equal multiples of 364 days by multiple linear and log-linear fixed-effects regression modelling (covariables: e.g., wind velocity, amount of precipitation, height of inversion base, school holidays, truck-free periods. Additionally, the continuous half-hour data was collapsed into 4-week averages and pooled with the diffuse sampler data to perform joint analysis.More than 3,000,000 quadruplets of continuous measurements (half-hour averages were identified at 38 index and 45 reference stations. Pooling with diffuse sampler data from 15 index and 10 reference stations lead to more than 4,000 quadruplets for joint analyses of 4-week averages. Mean LEZ effects on NO2, NO, and NOx concentrations (reductions were estimated to be at most -2 µg/m(3 (or -4%. The 4-week averages of NO2 concentrations at index stations after LEZ introduction were 55 µg/m(3 (median and mean values or 82 µg/m(3 (95th percentile.This is the first study investigating comprehensively the effectiveness of LEZs to reduce NO2, NO, and NOx concentrations controlling for most relevant potential confounders. Our analyses indicate that there is a statistically significant, but rather small reduction of NO2, NO, and NOx concentrations associated with LEZs.

  2. Bright x-ray sources from laser irradiation of foams with high concentration of Ti

    Energy Technology Data Exchange (ETDEWEB)

    Pérez, F., E-mail: perez75@llnl.gov; Patterson, J. R.; May, M.; Colvin, J. D.; Biener, M. M.; Wittstock, A.; Kucheyev, S. O.; Charnvanichborikarn, S.; Satcher, J. H.; Gammon, S. A.; Poco, J. F.; Fournier, K. B. [Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, California 94550 (United States); Fujioka, S.; Zhang, Z.; Ishihara, K.; Tanaka, N.; Ikenouchi, T.; Nishimura, H. [Institute of Laser Engineering, Osaka University, 2-6 Yamada-Oka, Suita, Osaka 565-0871 (Japan)

    2014-02-15

    Low-density foams irradiated by a 20 kJ laser at the Omega laser facility (Laboratory for Laser Energetics, Rochester, NY, USA) are shown to convert more than 5% of the laser energy into 4.6 to 6.0 keV x rays. This record efficiency with foam targets is due to novel fabrication techniques based on atomic-layer-deposition of Ti atoms on an aerogel scaffold. A Ti concentration of 33 at. % was obtained in a foam with a total density of 5 mg/cm{sup 3}. The dynamics of the ionization front through these foams were investigated at the 1 kJ laser of the Gekko XII facility (Institute for Laser Engineering, Osaka, Japan). Hydrodynamic simulations can reproduce the average electron temperature but fail to predict accurately the heat front velocity in the foam. This discrepancy is shown to be unrelated to the possible water adsorbed in the foam but could be attributed to effects of the foam micro-structure.

  3. Relative effects of climate and source strength on atmospheric lead concentrations in Auckland, New Zealand

    Science.gov (United States)

    Power, H. C.; de Freitas, C. R.; Hay, J. E.

    1992-06-01

    Atmospheric lead levels were examined to assess the consequences of the 46 percent reduction in the lead content of premium grade petrol in New Zealand. Since this change was implemented in July 1986 observed levels of atmospheric lead decreased by 38 percent, but all or part of this reduction may have been due to factors other than fluctuations in lead emissions, notably variations in climate. Analysis of detailed atmospheric lead, meteorological and traffic data measured contemporaneously provided insight into the atmospheric processes influencing lead levels in Auckland and formed the basis of a statistical model capable of predicting monthly lead concentrations. The model was used to predict lead levels in Auckland for the period July 1986 through to July 1989 in the absence of any reduction in the lead content of petrol. Comparison with values observed for the same period showed that all of the reduction in atmospheric lead levels since July 1986 can be attributed to the reduction in the lead content of petrol. Policy planning implications of such a finding are considered.

  4. A comparison between evaporation ponds and evaporation surfaces as a source of the concentrated salt brine for salt gradient maintenance at Tajoura solar pond

    International Nuclear Information System (INIS)

    Ramadan, Abdulghani M.; Agha, Khairy R.; Abughres, M.

    2012-01-01

    One of the main problems that negatively affect the operation of salt gradient solar ponds and influence its thermal stability is the maintenance of salt gradient profile. Evaporation pond (EP) is designed to generate the salt which lost upward salt diffusion from the lower convective zone (LCZ) of the solar pond. Another attractive method is the evaporation surface facility (ES). Regions with moderate to high precipitation favor Evaporation Surface over Evaporation Ponds. Dry climates will generally favor Evaporation Ponds for the brine re-concentration. In previous studies [1-3], the authors have shown that the (EP) of Tajoura's Experimental Solar Pond (TESP) is under sized and can provide only about 30% of the salt required by a Salt Gradient Solar Pond (SGSP). The anticipated size of (EP) was estimated and presented in those studies under different design conditions, including Summer, Autumn and Spring designs, while the winter design was excluded due to the low rates of net evaporation during the winter season. In addition, the results presented were predicted for the first three years of operation. The daily variations of brine concentration in the (EP) of (TESP) and those based on different designs were predicted and discussed under different scenarios. The quantities of brine provided by the evaporation pond and that required by SGSP were predicted for both cases of surface water flushing (fresh water and sea-water) under the different design conditions as shown in Table 1. This paper investigates the differences between (EP) and (ES) both as a source for salt brine generation by evaporation. The effect of (EP) depth on the area ratio and daily variations of salt concentrations for three years of operation is shown. Results show that evaporation can be a reasonable method for salt brine generation. Reducing the depth of (EP) improves the capability of (EP) for brine re-concentration. It also increases the (EP) surface area for the same quantity of

  5. Comparison of remote sensing data sources and techniques for identifying and classifying alien invasive vegetation in riparian zones

    CSIR Research Space (South Africa)

    Rowlinson, LC

    1999-10-01

    Full Text Available yield the most accurate and cost-effective results. The least cost-effective data sources were found to be 1:10 000 colour aerial photographs and digital aerial photographs and the least accurate data sources were aerial videography and Landsat thematic...

  6. Relating runoff generation mechanisms to concentration-discharge relationships in catchments with well-characterized Critical Zone structures and hydrologic dynamics

    Science.gov (United States)

    Hahm, W. J.; Wang, J.; Druhan, J. L.; Rempe, D.; Dietrich, W. E.

    2017-12-01

    Stream solute concentration-discharge (C-Q) relationships integrate catchment-scale hydrologic and geochemical processes, potentially yielding valuable information about runoff generation and weathering mechanisms. However, recent compilations have established that chemostasis—the condition where solute concentrations are invariant across large ranges of runoff—is observed in watersheds of diverse lithology, climate, and topography, suggesting an equifinality of the C-Q relationship independent of hydrologic process. Here we explore C-Q signals in contrasting catchments of the Eel River Critical Zone (CZ) Observatory in the Northern California Coast Ranges, where, unlike most watersheds where chemostasis has been observed, hillslope hydrologic processes are well characterized via years of intensive hydrologic monitoring. Our two catchments in the Franciscan Complex have radically different runoff generation mechanisms arising from differences in CZ structure: at Elder Creek (Coastal Belt), rain passes vertically as unsaturated flow through soil, saprolite, and a thick weathered rock zone before perching as groundwater on fresh bedrock and flowing laterally through fractures to generate streamflow, resulting in nearly chemostatic major cation behavior (power law C-Q slopes (B) ≈ 0 to -0.1). At Dry Creek (Central Belt), the thin (2 to 3 m) hydrologically active CZ completely saturates in most storm events, generating saturation overland flow across the landscape. New data from Dry Creek reveal log-log C-Q relationships for major cations that exhibit negative curvature, indicating a trend towards increasing dilution at higher flow rates and a possible C-Q signature of overland flow. High geomorphic channel drainage density (16.9 km/km2) results in short flow paths and, presumably, short water hillslope residence times at high runoff when overland flow dominates (> 50 mm d-1). Surprisingly, even at these high runoff rates, pure dilution does not occur (high

  7. Magnetic Data Interpretation for the Source-Edge Locations in Parts of the Tectonically Active Transition Zone of the Narmada-Son Lineament in Central India

    Science.gov (United States)

    Ghosh, G. K.

    2016-02-01

    The study has been carried out in the transition zone of the Narmada-Son lineament (NSL) which is seismically active with various geological complexities, upwarp movement of the mantle material into the crust through fault, fractures lamination and upwelling. NSL is one of the most prominent lineaments in central India after the Himalaya in the Indian geology. The area of investigation extends from longitude 80.25°E to 81.50°E and latitude 23.50°N to 24.37°N in the central part of the Indian continent. Different types of subsurface geological formations viz. alluvial, Gondwana, Deccan traps, Vindhyan, Mahakoshal, Granite and Gneisses groups exist in this area with varying geological ages. In this study area tectonic movement and crustal variation have been taken place during the past time and which might be reason for the variation of magnetic field. Magnetic anomaly suggests that the area has been highly disturbed which causes the Narmada-Son lineament trending in the ENE-WSW direction. Magnetic anomaly variation has been taken place due to the lithological variations subject to the changes in the geological contacts like thrusts and faults in this area. Shallow and deeper sources have been distinguished using frequency domain analysis by applying different filters. To enhance the magnetic data, various types of derivatives to identify the source-edge locations of the causative source bodies. The present study carried out the interpretation using total horizontal derivative, tilt angle derivative, horizontal tilt angle derivative and Cos (θ) derivative map to get source-edge locations. The results derived from various derivatives of magnetic data have been compared with the basement depth solutions calculated from 3D Euler deconvolution. It is suggested that total horizontal derivative, tilt angle derivative and Cos (θ) derivative are the most useful tools for identifying the multiple source edge locations of the causative bodies in this tectonically active

  8. PM10 concentration levels at an urban and background site in Cyprus: the impact of urban sources and dust storms.

    Science.gov (United States)

    Achilleos, Souzana; Evans, John S; Yiallouros, Panayiotis K; Kleanthous, Savvas; Schwartz, Joel; Koutrakis, Petros

    2014-12-01

    Air quality in Cyprus is influenced by both local and transported pollution, including desert dust storms. We examined PM10 concentration data collected in Nicosia (urban representative) from April 1, 1993, through December 11, 2008, and in Ayia Marina (rural background representative) from January 1, 1999, through December 31, 2008. Measurements were conducted using a Tapered Element Oscillating Micro-balance (TEOM). PM10 concentrations, meteorological records, and satellite data were used to identify dust storm days. We investigated long-term trends using a Generalized Additive Model (GAM) after controlling for day of week, month, temperature, wind speed, and relative humidity. In Nicosia, annual PM10 concentrations ranged from 50.4 to 63.8 μg/m3 and exceeded the EU annual standard limit enacted in 2005 of 40 μg/m3 every year A large, statistically significant impact of urban sources (defined as the difference between urban and background levels) was seen in Nicosia over the period 2000-2008, and was highest during traffic hours, weekdays, cold months, and low wind conditions. Our estimate of the mean (standard error) contribution of urban sources to the daily ambient PM10 was 24.0 (0.4) μg/m3. The study of yearly trends showed that PM10 levels in Nicosia decreased from 59.4 μg/m3 in 1993 to 49.0 μg/m3 in 2008, probably in part as a result of traffic emission control policies in Cyprus. In Ayia Marina, annual concentrations ranged from 27.3 to 35.6 μg/m3, and no obvious time trends were observed. The levels measured at the Cyprus background site are comparable to background concentrations reported in other Eastern Mediterranean countries. Average daily PM10 concentrations during desert dust storms were around 100 μg/m3 since 2000 and much higher in earlier years. Despite the large impact ofdust storms and their increasing frequency over time, dust storms were responsible for a small fraction of the exceedances of the daily PM10 limit. Implications: This

  9. ANEMOS: A computer code to estimate air concentrations and ground deposition rates for atmospheric nuclides emitted from multiple operating sources

    International Nuclear Information System (INIS)

    Miller, C.W.; Sjoreen, A.L.; Begovich, C.L.; Hermann, O.W.

    1986-11-01

    This code estimates concentrations in air and ground deposition rates for Atmospheric Nuclides Emitted from Multiple Operating Sources. ANEMOS is one component of an integrated Computerized Radiological Risk Investigation System (CRRIS) developed for the US Environmental Protection Agency (EPA) for use in performing radiological assessments and in developing radiation standards. The concentrations and deposition rates calculated by ANEMOS are used in subsequent portions of the CRRIS for estimating doses and risks to man. The calculations made in ANEMOS are based on the use of a straight-line Gaussian plume atmospheric dispersion model with both dry and wet deposition parameter options. The code will accommodate a ground-level or elevated point and area source or windblown source. Adjustments may be made during the calculations for surface roughness, building wake effects, terrain height, wind speed at the height of release, the variation in plume rise as a function of downwind distance, and the in-growth and decay of daughter products in the plume as it travels downwind. ANEMOS can also accommodate multiple particle sizes and clearance classes, and it may be used to calculate the dose from a finite plume of gamma-ray-emitting radionuclides passing overhead. The output of this code is presented for 16 sectors of a circular grid. ANEMOS can calculate both the sector-average concentrations and deposition rates at a given set of downwind distances in each sector and the average of these quantities over an area within each sector bounded by two successive downwind distances. ANEMOS is designed to be used primarily for continuous, long-term radionuclide releases. This report describes the models used in the code, their computer implementation, the uncertainty associated with their use, and the use of ANEMOS in conjunction with other codes in the CRRIS. A listing of the code is included in Appendix C

  10. ANEMOS: A computer code to estimate air concentrations and ground deposition rates for atmospheric nuclides emitted from multiple operating sources

    Energy Technology Data Exchange (ETDEWEB)

    Miller, C.W.; Sjoreen, A.L.; Begovich, C.L.; Hermann, O.W.

    1986-11-01

    This code estimates concentrations in air and ground deposition rates for Atmospheric Nuclides Emitted from Multiple Operating Sources. ANEMOS is one component of an integrated Computerized Radiological Risk Investigation System (CRRIS) developed for the US Environmental Protection Agency (EPA) for use in performing radiological assessments and in developing radiation standards. The concentrations and deposition rates calculated by ANEMOS are used in subsequent portions of the CRRIS for estimating doses and risks to man. The calculations made in ANEMOS are based on the use of a straight-line Gaussian plume atmospheric dispersion model with both dry and wet deposition parameter options. The code will accommodate a ground-level or elevated point and area source or windblown source. Adjustments may be made during the calculations for surface roughness, building wake effects, terrain height, wind speed at the height of release, the variation in plume rise as a function of downwind distance, and the in-growth and decay of daughter products in the plume as it travels downwind. ANEMOS can also accommodate multiple particle sizes and clearance classes, and it may be used to calculate the dose from a finite plume of gamma-ray-emitting radionuclides passing overhead. The output of this code is presented for 16 sectors of a circular grid. ANEMOS can calculate both the sector-average concentrations and deposition rates at a given set of downwind distances in each sector and the average of these quantities over an area within each sector bounded by two successive downwind distances. ANEMOS is designed to be used primarily for continuous, long-term radionuclide releases. This report describes the models used in the code, their computer implementation, the uncertainty associated with their use, and the use of ANEMOS in conjunction with other codes in the CRRIS. A listing of the code is included in Appendix C.

  11. AnalysisThe Availability of Using Concentrated Solar Power (CSP as Electricity Source in Al-Hilla City

    Directory of Open Access Journals (Sweden)

    Wisam Shamkhi Jaber

    2017-03-01

    Full Text Available The needing of using clean energy increases every year because of the negative impact of emissions from electricity power plant and to reduce the costs of generating power by using natural energies like solar, wind, and other sources. The availability of using solar energy as source of producing electricity in Al-Hilla city by using Concentrating Solar Power (CSP was investigated in this research. The major parameters in this study were the city position, and the annually amount of solar received, also, number of charts related to solar parameters for the management of CSP were derived and showed in this research. The using of CSP as electricity power can be important solution to force the problem of high cost of electricity power fuel needed and the lack of power produced because of increasing of power consumed specially in summer season.

  12. Analysis on the inbound tourist source market in Jiangxi based on geographic concentration index and market competition status

    Science.gov (United States)

    Yu, Tong; Ye, Yue-li

    2018-05-01

    In accordance with the related data of Statistical Yearbook of Jiangxi (2007—2016), conduct analysis on the development situation of inbound tourist source market in Jiangxi based on geographic concentration index and market competition status. The result shows: when the geographic concentration index of the inbound tourism market in Jiangxi presents an increasing decline trend, the tourism-generating countries of the inbound tourism in Jiangxi are getting more and more disperse, the tourist markets present the diversified feature and the inbound tourism market tends to be stable; besides, the analysis result of the market competition status shows that the inbound tourism development in Jiangxi has transformed from the rapid development to stable development.

  13. Calculation of NO2 concentration in air from the point source Tepláreň Košice

    Directory of Open Access Journals (Sweden)

    Jozef Mačala

    2007-06-01

    Full Text Available The most threatened part of environment is air and its pollution increases rapidly. In the local rate, the weight of air pollution increases by reason of a more intensive influence on the human population. The problem is significant mostly in urban areas, places with the biggest concentration of peoples, industry and transport. The greatest producers of air pollution are various parts of industry, heat production and traffic. For a complex valuation, the influence of particular parts of industry is needed to know the sources of air pollution in the specific area. Only with a knowledge, it is possible to evaluate a spotted area in terms of air quality.

  14. Determination of trace concentrations of chlorine in aqueous solutions by high-resolution continuum source graphite furnace molecular absorption spectrometry

    Science.gov (United States)

    Machyňák, Ľubomír; Čacho, František; Němeček, Martin; Beinrohr, Ernest

    2016-11-01

    Trace concentrations of total chlorine were determined by means of molecular absorption of indium mono-chloride (InCl) at 267.217 nm using high-resolution continuum source graphite furnace molecular absorption spectrometry. The effects of chemical modifiers and the amount of In on the sensitivity and accuracy were investigated. The optimum pyrolysis and vaporization temperatures were 600 °C and 1400 °C, respectively. The limit of detection and characteristic mass were found to be 0.10 ng and 0.21 ng, respectively. Potential non-spectral and spectral interferences were tested for various metals and non-metals at concentrations up to 50 mg L- 1 and for phosphoric, sulphuric and nitric acids. No spectral interferences were observed. Significant non-spectral interferences were observed with F, Br, and I at concentrations higher than 1 mg L- 1, 5 mg L- 1 and 25 mg L- 1, respectively, which is probably caused by formation of competitive indium halogen molecules. Higher concentrations of mineral acids depressed the signal owing to the formation of volatile HCl. The calibration curve was linear in the range between 0.3 and 10 ng with a correlation coefficient of R = 0.993. The elaborated method was used for the chlorine determination in various waters and a drug sample.

  15. Identification of benign and malignant thyroid nodules by in vivo iodine concentration measurement using single-source dual energy CT

    Science.gov (United States)

    Gao, Shun-Yu; Zhang, Xiao-Yan; Wei, Wei; Li, Xiao-Ting; Li, Yan-Ling; Xu, Min; Sun, Ying-Shi; Zhang, Xiao-Peng

    2016-01-01

    Abstract This study proposed to determine whether in vivo iodine concentration measurement by single-source dual energy (SSDE) CT can improve differentiation between benign and malignant thyroid nodules. In total, 53 patients presenting with thyroid nodules underwent SSDE CT scanning. Iodine concentrations were measured for each nodule and normal thyroid tissue using the GSI-viewer image analysis software. A total of 26 thyroid nodules were malignant in 26 patients and confirmed by surgery; 33 nodules from 27 patients were benign, with 10 confirmed by surgery and others after follow-up. Iodine concentrations with plain CT were significantly lower in malignant than benign nodules (0.47 ± 0.20 vs 1.17 ± 0.38 mg/mL, P = 0.00). Receiver operating characteristic (ROC) curve showed an area under the curve (AUC) of 0.93; with a cutoff of 0.67, iodine concentration showed 92.3% sensitivity and 88.5% specificity in diagnosing malignancy. Iodine concentration obtained by enhanced and plain CT were significantly higher in malignant than benign nodules (9.05 ± 3.35 vs 3.46 ± 2.24 mg/mL, P = 0.00). ROC curve analysis showed an AUC of 0.93; with a cutoff value of 3.37, iodine concentration displayed 78% sensitivity, 95% specificity in diagnosing malignancy. Combining unenhanced with enhanced iodine concentrations, the diagnostic equation was: Y = –8.641 × unenhanced iodine concentration + 0.663 × iodine concentration. ROC curve showed an AUC of 0.98 (95% CI, 0.94, 1.00). With Y ≥ –2 considered malignancy, diagnostic sensitivity and specificity were 96%, 96.3%, respectively. This study concluded that SSDE CT can detect the differences in iodine uptake and blood supply between benign and malignant thyroid lesions. PMID:27684811

  16. Applications of Ground-based Mobile Atmospheric Monitoring: Real-time Characterization of Source Emissions and Ambient Concentrations

    Science.gov (United States)

    Goetz, J. Douglas

    Gas and particle phase atmospheric pollution are known to impact human and environmental health as well as contribute to climate forcing. While many atmospheric pollutants are regulated or controlled in the developed world uncertainty still remains regarding the impacts from under characterized emission sources, the interaction of anthropogenic and naturally occurring pollution, and the chemical and physical evolution of emissions in the atmosphere, among many other uncertainties. Because of the complexity of atmospheric pollution many types of monitoring have been implemented in the past, but none are capable of perfectly characterizing the atmosphere and each monitoring type has known benefits and disadvantages. Ground-based mobile monitoring with fast-response in-situ instrumentation has been used in the past for a number of applications that fill data gaps not possible with other types of atmospheric monitoring. In this work, ground-based mobile monitoring was implemented to quantify emissions from under characterized emission sources using both moving and portable applications, and used in a novel way for the characterization of ambient concentrations. In the Marcellus Shale region of Pennsylvania two mobile platforms were used to estimate emission rates from infrastructure associated with the production and transmission of natural gas using two unique methods. One campaign investigated emissions of aerosols, volatile organic compounds (VOCs), methane, carbon monoxide (CO), nitrogen dioxide (NO2), and carbon dioxide (CO 2) from natural gas wells, well development practices, and compressor stations using tracer release ratio methods and a developed fenceline tracer release correction factor. Another campaign investigated emissions of methane from Marcellus Shale gas wells and infrastructure associated with two large national transmission pipelines using the "Point Source Gaussian" method described in the EPA OTM-33a. During both campaigns ambient concentrations

  17. Active Fault Near-Source Zones Within and Bordering the State of California for the 1997 Uniform Building Code

    Science.gov (United States)

    Petersen, M.D.; Toppozada, Tousson R.; Cao, T.; Cramer, C.H.; Reichle, M.S.; Bryant, W.A.

    2000-01-01

    The fault sources in the Project 97 probabilistic seismic hazard maps for the state of California were used to construct maps for defining near-source seismic coefficients, Na and Nv, incorporated in the 1997 Uniform Building Code (ICBO 1997). The near-source factors are based on the distance from a known active fault that is classified as either Type A or Type B. To determine the near-source factor, four pieces of geologic information are required: (1) recognizing a fault and determining whether or not the fault has been active during the Holocene, (2) identifying the location of the fault at or beneath the ground surface, (3) estimating the slip rate of the fault, and (4) estimating the maximum earthquake magnitude for each fault segment. This paper describes the information used to produce the fault classifications and distances.

  18. Impending sources of energy to replace fire wood in semi arid climatic zones: A case study in Ethiopia

    Directory of Open Access Journals (Sweden)

    Mihret Dananto Ulsido

    2013-06-01

    Full Text Available The present study paper shows an alternative source of energy that can decrease the extensive use of fire wood in Ethiopia. The country’s entire rural area and significant part of urban population is completely dependent on fire wood as a source of energy. This practice takes its own toll, the forest is on the verge of being wiped out and as a result a clear change of climate and loss of natural biodiversity resources is visible. Fire wood is not the only source of energy available in the country. In this paper, based on their low cost, construction material availability and the required unskilled labor it is shown that biogas and solar energy are potentially feasible source of energy to replace firewood for cooking.

  19. Effect of nitrogen source concentration on curdlan production by Agrobacterium sp. ATCC 31749 grown on prairie cordgrass hydrolysates.

    Science.gov (United States)

    West, Thomas P

    2016-01-01

    The effect of nitrogen source concentration on the production of the polysaccharide curdlan by the bacterium Agrobacterium sp. ATCC 31749 from hydrolysates of prairie cordgrass was examined. The highest curdlan concentrations were produced by ATCC 31749 when grown on a medium containing a solids-only hydrolysate and the nitrogen source ammonium phosphate (2.2 mM) or on a medium containing a complete hydrolysate and 3.3 mM ammonium phosphate. The latter medium sustained a higher level of bacterial curdlan production than the former medium after 144 hr. Biomass production by ATCC 31749 was highest after 144 hr when grown on a medium containing a solids-only hydrolysate and 2.2 or 8.7 mM ammonium phosphate. On the medium containing the complete hydrolysate, biomass production by ATCC 31749 was highest after 144 hr when 3.3 mM ammonium phosphate was present. Bacterial biomass production after 144 hr was greater on the complete hydrolysate medium compared to the solids-only hydrolysate medium. Curdlan yield produced by ATCC 31749 after 144 hr from the complete hydrolysate medium containing 3.3 mM ammonium phosphate was higher than from the solids-only hydrolysate medium containing 2.2 mM ammonium phosphate.

  20. In vitro fermentation pattern and acidification potential of different sources of carbohydrates for ruminants given high concentrate diets

    Energy Technology Data Exchange (ETDEWEB)

    Amanzougarene, Z.; Yuste, S.; Vega, A. De; Fondevila, M.

    2017-07-01

    The in vitro fermentation pattern of five sources of carbohydrates of differing nature (maize grain, MZ; sucrose, SU; wheat bran, WB; sugarbeet pulp, BP; and citrus pulp, CT) under conditions of high concentrate diets for ruminants was studied. A first 8 h incubation trial was performed under optimal pH using inoculum from ewes given a fibrous diet, to compare fermentative characteristics of substrates. As planned, incubation pH ranged within 6.3 to 6.6. The gas produced from CT was higher than MZ, SU and BP from 4 and 6 h onwards, and at 8 h, respectively (p<0.05). There were no differences (p>0.05) on total volatile fatty acid (VFA) concentration, nor on acetate or propionate proportions, but butyrate was lowest (p<0.05) with CT and BP. The second incubation trial was performed in a poorly-buffered medium, with inoculum from ewes given a concentrate diet. All substrates showed a gradual drop of pH, being lowest with SU after 4 h (p<0.05). Throughout the incubation, gas production was highest with CT and lowest with MZ and BP (p<0.05). Total 8 h VFA concentration was higher with CT than BP, SU and MZ (p<0.05). Acetate proportion was higher, and that of propionate lower, with BP than WB (p<0.05), butyrate proportion being higher with MZ and WB than with BP and CT (p<0.05). Lactic acid concentration was higher (p<0.05) with SU than WB and BP. Fermentation characteristics and acidification potential of feeds depend on the nature of their carbohydrate fraction, and must be considered for practical applications.

  1. Characterizing multiple sources and interaction in the critical zone through Sr-isotope tracing of surface and groundwater

    Science.gov (United States)

    Negrel, Philippe; Pauwels, Hélène

    2017-04-01

    The Critical Zone (CZ) is the lithosphere-atmosphere boundary where complex physical, chemical and biological processes occurs and control the transfer and storage of water and chemical elements. This is the place where life-sustaining resources are, where nutrients are being released from the rocks. Because it is the place where we are living, this is a fragile zone, a critical zone as a perturbed natural ecosystem. Water resources in hard-rocks commonly involve different hydrogeological compartments such as overlying sediments, weathered rock, the weathered-fissured zone, and fractured bedrock. Streams, lakes and wetlands that drain such environments can drain groundwater, recharge groundwater, or do both. Groundwater resources in many countries are increasingly threatened by growing demand, wasteful use, and contamination. Surface water and shallow groundwater are particularly vulnerable to pollution, while deeper resources are more protected from contamination. Here, we first report on Sr isotope data as well as major ions, from shallow and deep groundwater in several granite and schist areas over France with intensive agriculture covering large parts of these catchments. In three granite and Brioverian 'schist' areas of the Armorican Massif, the range in Sr contents in groundwater from different catchments agrees with previous work on groundwater sampled from granites in France. The Sr content is well correlated with Mg and both are partly related to agricultural practices and water rock interaction. The relationship between Sr- isotope and Mg/Sr ratios allow defining the different end-members, mainly rain, agricultural practice and water-rock interaction. The data from the Armorican Massif and other surface and groundwater for catchment draining silicate bedrocks (300-450Ma) like the Hérault, Seine, Moselle, Garonne, Morvan, Margeride, Cantal, Pyrénées and Vosges are scattered between at least three geochemical signatures. These include fertilizer and

  2. Blood cadmium concentrations and environmental exposure sources in newcomer South and East Asian women in the Greater Toronto Area, Canada

    International Nuclear Information System (INIS)

    Wiseman, C.L.S.; Parnia, A.; Chakravartty, D.; Archbold, J.; Zawar, N.; Copes, R.; Cole, D.C.

    2017-01-01

    Background: Immigrant women are often identified as being particularly vulnerable to environmental exposures and health effects. The availability of biomonitoring data on newcomers is limited, thus, presenting a challenge to public health practitioners in the identification of priorities for intervention. Objectives: In fulfillment of data needs, the purpose of this study was to characterize blood concentrations of cadmium (Cd) among newcomer women of reproductive age (19–45 years of age) living in the Greater Toronto Area (GTA), Canada and to assess potential sources of environmental exposures. Methods: A community-based model, engaging peer researchers from the communities of interest, was used for recruitment and follow-up purposes. Blood samples were taken from a total of 211 newcomer women from South and East Asia, representing primary, regional origins of immigrants to the GTA, and environmental exposure sources were assessed via telephone survey. Metal concentrations were measured in blood samples (diluted with 0.5% (v/v) ammonium hydroxide and 0.1% (v/v) octylphenol ethoxylate) using a quadrupole ICP-MS. Survey questions addressed a wide range of environmental exposure sources, including dietary and smoking patterns and use of nutritional supplements, herbal products and cosmetics. Results: A geometric mean (GM) blood Cd concentration of 0.39 µg/L (SD:±2.07 µg/L) was determined for study participants (min/max: <0.045 µg /L (LOD)/2.36 µg/L). Several variables including low educational attainment (Relative Ratio (RR) (adjusted)=1.50; 95% CI 1.17–1.91), milk consumption (RR (adjusted)=0.86; 95% CI 0.76–0.97), and use of zinc supplements (RR (adjusted)=0.76; 95% CI 0.64–0.95) were observed to be significantly associated with blood Cd concentrations in the adjusted regression model. The variable domains socioeconomic status (R 2 adj =0.11) and country of origin (R 2 adj =0.236) were the strongest predictors of blood Cd. Conclusion: Blood Cd

  3. Blood cadmium concentrations and environmental exposure sources in newcomer South and East Asian women in the Greater Toronto Area, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Wiseman, C.L.S., E-mail: clare.wiseman@utoronto.ca [School of the Environment, University of Toronto (Canada); Dalla Lana School of Public Health, University of Toronto (Canada); Parnia, A.; Chakravartty, D. [Dalla Lana School of Public Health, University of Toronto (Canada); Archbold, J. [Toronto Public Health (Canada); Zawar, N. [Dalla Lana School of Public Health, University of Toronto (Canada); Copes, R. [Dalla Lana School of Public Health, University of Toronto (Canada); Public Health Ontario (Canada); Cole, D.C. [School of the Environment, University of Toronto (Canada); Dalla Lana School of Public Health, University of Toronto (Canada)

    2017-04-15

    Background: Immigrant women are often identified as being particularly vulnerable to environmental exposures and health effects. The availability of biomonitoring data on newcomers is limited, thus, presenting a challenge to public health practitioners in the identification of priorities for intervention. Objectives: In fulfillment of data needs, the purpose of this study was to characterize blood concentrations of cadmium (Cd) among newcomer women of reproductive age (19–45 years of age) living in the Greater Toronto Area (GTA), Canada and to assess potential sources of environmental exposures. Methods: A community-based model, engaging peer researchers from the communities of interest, was used for recruitment and follow-up purposes. Blood samples were taken from a total of 211 newcomer women from South and East Asia, representing primary, regional origins of immigrants to the GTA, and environmental exposure sources were assessed via telephone survey. Metal concentrations were measured in blood samples (diluted with 0.5% (v/v) ammonium hydroxide and 0.1% (v/v) octylphenol ethoxylate) using a quadrupole ICP-MS. Survey questions addressed a wide range of environmental exposure sources, including dietary and smoking patterns and use of nutritional supplements, herbal products and cosmetics. Results: A geometric mean (GM) blood Cd concentration of 0.39 µg/L (SD:±2.07 µg/L) was determined for study participants (min/max: <0.045 µg /L (LOD)/2.36 µg/L). Several variables including low educational attainment (Relative Ratio (RR) (adjusted)=1.50; 95% CI 1.17–1.91), milk consumption (RR (adjusted)=0.86; 95% CI 0.76–0.97), and use of zinc supplements (RR (adjusted)=0.76; 95% CI 0.64–0.95) were observed to be significantly associated with blood Cd concentrations in the adjusted regression model. The variable domains socioeconomic status (R{sup 2}{sub adj}=0.11) and country of origin (R{sup 2}{sub adj}=0.236) were the strongest predictors of blood Cd. Conclusion

  4. Observations of fine particulate nitrated phenols in four sites in northern China: concentrations, source apportionment, and secondary formation

    Directory of Open Access Journals (Sweden)

    L. Wang

    2018-03-01

    Full Text Available Filter samples of fine particulate matters were collected at four sites in northern China (urban, rural, and mountain in summer and winter, and the contents of nine nitrated phenols were quantified in the laboratory with the use of ultra-high-performance liquid chromatography coupled with mass spectrometry. During the sampling periods, the concentrations of particulate nitrated phenols exhibited distinct temporal and spatial variation. On average, the total concentration of particulate nitrated phenols in urban Jinan in the wintertime reached 48.4 ng m−3, and those in the summertime were 9.8, 5.7, 5.9, and 2.5 ng m−3 in urban Jinan, rural Yucheng and Wangdu, and Mt. Tai, respectively. The elevated concentrations of nitrated phenols in wintertime and in urban areas demonstrate the apparent influences of anthropogenic sources. The positive matrix factorization receptor model was then applied to determine the origins of particulate nitrated phenols in northern China. The five major source factors were traffic, coal combustion, biomass burning, secondary formation, and aged coal combustion plume. Among them, coal combustion played a vital role, especially at the urban site in the wintertime, with a contribution of around 55 %. In the summertime, the observed nitrated phenols were highly influenced by aged coal combustion plumes at all of the sampling sites. Meanwhile, in remote areas, contributions from secondary formation were significant. Further correlation analysis indicates that nitrosalicylic acids were produced mostly from secondary formation that was dominated by NO2 nitration.

  5. Environmental concentration and atmospheric deposition of halogenated flame retardants in soil from Nepal: Source apportionment and soil-air partitioning.

    Science.gov (United States)

    Yadav, Ishwar Chandra; Devi, Ningombam Linthoingambi; Li, Jun; Zhang, Gan

    2018-02-01

    While various investigations have been driven on polybrominated diphenyl ethers (PBDEs) and other flame retardants (FRs) in different framework around the world, information about contamination and fate of PBDEs and other FRs in developing countries especially in the Indian subcontinent is uncommon. Nepal being located in the Indian subcontinent, very little is known about contamination level of semi-volatile organic pollutants discharged into the environment. This motivated us to investigate the environmental fate of halogenated flame retardant (HFRs) in Nepalese condition. In this study, we investigated the concentration, fate, and sources of 9 PBDEs, 2 dechlorane plus isomers (DPs), and 6 novel brominated flame retardants (NBFRs). Moreover, air-soil exchange and soil-air partitioning were also evaluated to characterize the pattern of air-soil exchange and environmental fate. In general, the concentrations of NBFRs in soil were more prevalent than PBDEs and DPs, and accounted 95% of ∑HFRs. By and large, the concentrations of NBFRs and DPs were measured high in Kathmandu, while PBDEs level exceeded in Pokhara. Principal component analysis (PCA) study suggested contributions from commercial penta-, octa-, and deca-BDEs products and de-bromination of highly brominated PBDEs as the significant source of PBDEs. Likewise, low f anti ratio suggested DPs in soil might have originated from long-range atmospheric transport from remote areas, while high levels of decabromodiphenyl ethane (DBDPE) in soil were linked with the use of wide varieties of consumer products. The estimated fugacity fraction (ff) for individual HFR was quite lower (soil is overwhelming. Soil-air partitioning study revealed neither octanol-air partition coefficient (K OA ) nor black carbon partition coefficient (K BC-A ) is an appropriate surrogate for soil organic matter (SOM), subsequently, absorption by SOM has no or little role in the partitioning of HFRs. Copyright © 2017 Elsevier Ltd. All

  6. Influence of energy concentration and source on the utilization of feed protein and NPN in lambs. 3

    International Nuclear Information System (INIS)

    Ulbrich, M.; Geissler, C.; Bassuny, S.M.; Borowiec, F.; Hoffmann, M.

    1989-01-01

    In an N balance experiment with male crossbreeding lambs at an age of 3-4 months four different rations were given differing in energy concentration (high > 700 EFU cattle /kg DM and low cattle /kg DM) and in the energy source (sugar, starch or crude fibre) with crude protein intake being almost equal. The rations contained 2% urea. Microbial protein synthesis in the rumen was assessed according to Roth and Kichgessner (1978) (1), Rys et al. (1975) (2) and Bickel-Baumann and Landis (1986) (3) on the basis of allantoin excretion in urine. The highest ruminal protein synthesis quotas were 868-921 mg protein N per kg LW 0.75 in (2). In (3) 723-766 mg protein N/kg LW 0.75 were synthesized. From the 15 N labelling of the supplemented urea and the excreted allantoin it could be calculated that 26-40% of the microbial protein resulted from the urea-N of the ration. Despite a high crude protein content of the ration of between 16 and 17% in the DM and a relation of NPN: pure protein of 0.95 the utilization of the NPN in the ration was relatively high but slightly lower than the utilization of pure protein. The variants with higher energy concentration showed as a tendency higher allantoin excretion in spite of slightly lower dry matter intake and a slightly higher NPN utilization than the variants with lower energy concentration. (author)

  7. Are plasma homocysteine concentrations in Brazilian adolescents influenced by the intake of the main food sources of natural folate?

    Science.gov (United States)

    Bigio, Roberta Schein; Verly, Eliseu; de Castro, Michelle Alessandra; Cesar, Chester Luis Galvão; Fisberg, Regina Mara; Marchioni, Dirce Maria Lobo

    2013-01-01

    Folate, a B vitamin, has been associated with a reduced concentration of plasma homocysteine (phcy), a marker of cardiovascular disease. The contribution of fruits and vegetables (FV) and other natural folate-rich foods to folate intake and folate status in Brazilian adolescents has hardly been determined. To investigate the intake of FV and beans and its association with the concentration of phcy in adolescents. This was a cross-sectional population-based study with a complex sample survey, with 198 adolescents who completed two 24-hour dietary recalls, a food frequency questionnaire, and a fasting blood draw. Usual dietary intake estimates were derived applying the Multiple Source Method. Three different generalized linear models with a gamma distribution were developed for each sex to evaluate the relationship between phcy and tertiles of FV intake as well as to evaluate the relationship between phcy and tertiles of FV and bean intake. No association was found between phcy concentration and FV intake or between phcy and FV and beans. Serum folate and female sex were inversely related to phcy. Phcy was not related to FV or FV and beans; this may be attributable to a low intake of these food groups. Copyright © 2013 S. Karger AG, Basel.

  8. Identification of source and recharge zones in an aquifer system from water stable isotope. Case Study Bajo Cauca Antioqueno

    International Nuclear Information System (INIS)

    Palacio B, Paola Andrea; Betancur V, Teresita

    2008-01-01

    Hydrology and hydrogeochemical are auxiliary techniques to valid conceptual hydrogeology an recharge models. Stable isotopes from water trace sources and path flow and Tritium indicates age. This paper is about the use of D 18, D 2H y 3H to study the aquifer system on Bajo Cauca antioqueno

  9. Replacing soybean meal with gelatin extracted from cow skin and corn protein concentrate as a protein source in broiler diets.

    Science.gov (United States)

    Khalaji, S; Manafi, M; Olfati, Z; Hedyati, M; Latifi, M; Veysi, A

    2016-02-01

    Two experiments were conducted to investigate the effects of replacing soybean meal with gelatin extracted from cow skin and corn protein concentrate as a protein source in broiler diets. Experiments were carried out as a completely randomized design where each experiment involved 4 treatments of 6 replicates and 10 chicks in each pen. Soybean meal proteins in a corn-soy control diet were replaced with 15, 30, and 45% of cow skin gelatin (CSG) or corn protein concentrate (CPC), respectively, in experiments 1 and 2. BW and cumulative feed intake were measured at 7, 21, and 42 d of age. Blood characteristics, relative organs weight and length, ileal digesta viscosity, ileal morphology, and cecal coliform and Salmonella population were measured at 42 d of age. Apparent total tract digestibility of protein was determined during 35 to 42 d of age. Replacement of soybean meal with CSG severely inhibited BW gain, decreased feed intake, and increased FCR in broilers during the experimental period (P ≤ 0.01). The inclusion of CPC reduced BW and increased FCR significantly (P ≤ 0.05) at 21 and 42 d of age without any consequence in feed intake. Protein digestibility was reduced and ileal digesta viscosity was increased linearly by increasing the amount of CSG and CPC in the control diet (P ≤ 0.01). Replacement of soybean meal with CSG and CPC did not significantly alter blood cell profile and plasma phosphorus, creatinine, blood urea nitrogen, Aspartate transaminase, and HDL and LDL cholesterol concentration. The inclusion of CSG linearly (P ≤ 0.05) increased plasma uric acid concentration and alkaline phosphatase activity. Triglyceride and cholesterol levels were decreased significantly (P ≤ 0.05) when the amount of CSG replacement was 15%. The results of this experiment showed that using CSG and CPC negatively affects broiler performance and therefore is not a suitable alternative to soybean meal in commercial diets. © 2015 Poultry Science Association Inc.

  10. Successful large-scale hatchery culture of sandfish (Holothuria scabra using micro-algae concentrates as a larval food source

    Directory of Open Access Journals (Sweden)

    Thane A. Militz

    2018-02-01

    Full Text Available This paper reports methodology for large-scale hatchery culture of sandfish, Holothuria scabra, in the absence of live, cultured micro-algae. We demonstrate how commercially-available micro-algae concentrates can be incorporated into hatchery protocols as the sole larval food source to completely replace live, cultured micro-algae. Micro-algae concentrates supported comparable hatchery production of sandfish to that of live, cultured micro-algae traditionally used in large-scale hatchery culture. The hatchery protocol presented allowed a single technician to achieve production of more than 18,800 juvenile sandfish at 40 days post-fertilisation in a low-resource hatchery in Papua New Guinea. Growth of auricularia larvae fed micro-algae concentrates was represented by the equation length (μm = 307.8 × ln(day + 209.2 (R2 = 0.93 while survival over the entire 40 day hatchery cycle was described by the equation survival = 2 × day−1.06 (R2 = 0.74. These results show that micro-algae concentrates have great potential for simplifying hatchery culture of sea cucumbers by reducing infrastructural and technical resources required for live micro-algae culture. The hatchery methodology described in this study is likely to have applicability to low-resource hatcheries throughout the Indo-Pacific and could support regional expansion of sandfish hatchery production.

  11. Temporal characteristics of black carbon concentrations and its potential emission sources in a southern Taiwan industrial urban area.

    Science.gov (United States)

    Cheng, Yu-Hsiang; Lin, Chi-Chi; Liu, Jyh-Jian; Hsieh, Cheng-Ju

    2014-03-01

    This study investigates the temporal characteristics of black carbon and its potential emission sources, as well as the fractions of BC in PM2.5 levels in Kaohsiung urban area, which is an industrial city in southern Taiwan. Concentrations of BC and PM2.5 are monitored continuously from March 2006 to February 2010, using an aethalometer and a tapered element oscillating microbalance monitor. Additionally, the presence of organic compounds (or UV enhanced species) in particles at the sampling site is determined using the Delta-C (UVBC-BC) value. According to long-term measurement results, BC and PM2.5 concentrations are 3.33 and 34.0 μg m(-3), respectively, in the Kaohsiung urban area. The ratio of BC/PM2.5 is approximately 11 %. Low concentration of BC and PM2.5 in the summer of this study period is mostly likely owing to meteorological conditions that favored dispersion of local air pollutants. Nevertheless, BC concentrations peaked markedly during morning hours (7:00-11:00), likely owing to local traffic congestion. Measurement results suggest that BC is released from local traffic activities and emitted from industrial activities at this sampling site. Additionally, Delta-C values are significantly higher than zero during January-March and November-December periods in this industrial urban area, implying that UV enhanced species can be observed. At this sampling site, these UV enhanced species do not only originate from household activity and solid waste burning but also release from industrial activities. The elevated Delta-C values during nighttime (18:00-6:00) in the autumn and winter seasons are likely related to those UV enhanced species in the atmosphere, which can be condensed on particle surface under low temperature conditions. According to long-term measurement results, significantly positive Delta-C values can be observed under temperatures industrial parks and a coal-fired power plant.

  12. Emission from concentrated sources

    International Nuclear Information System (INIS)

    Ernst, G.

    1981-01-01

    Differential equations to describe the rising cloud of gas and its speed are derived for the case of an inversion layer at constant atmospheric temperature and the case of an indifferent layer of the atmosphere. The characteristics of the cloud of gas at the outlet of a natural draught wet cooling tower of a 1,000 MWe nuclear powerstation and a 600 MWe conventional powerstation are given. (DG) [de

  13. Concentrations of progesterone and insulin in serum of nonlactating dairy cows in response to carbohydrate source and processing.

    Science.gov (United States)

    Moriel, P; Scatena, T S; Sá Filho, O G; Cooke, R F; Vasconcelos, J L M

    2008-12-01

    Two experiments were conducted to investigate the effects of carbohydrate source and processing on serum progesterone (P4) and insulin concentrations of nonlactating dairy cows. In experiment 1, 12 ovariectomized grazing Gir x Holstein cows were stratified by body weight and body condition score, and randomly assigned to receive a supplement containing either finely ground corn or citrus pulp in a Latin square crossover design. Diets were fed individually, twice daily at a rate of 10.9 kg of dry matter per cow. Cows received a controlled intravaginal P4-releasing insert before the beginning of the study, and inserts were replaced every 7 d. During the first experimental period, cows were adapted to treatments from d 0 to 13 and blood was collected on d 14, whereas during the second experimental period cows were adapted to treatments from d 0 to 6 and blood samples were collected on d 7. In both periods, blood samples were collected immediately before and at 1, 2, 3, 4, 5, and 6 h after the first supplement feeding of the collection day. In experiment 2, the cows utilized in experiment 1 were randomly assigned to receive a supplement based on finely ground corn, coarsely ground corn, or high-moisture corn in a Latin square crossover design. Cows were fed and received the controlled intravaginal P4-releasing insert as in experiment 1. Within each of the 3 experimental periods, cows were adapted to diets from d 0 to 6, and blood samples were collected on d 7 as in experiment 1. Time effects were detected in experiments 1 and 2 because insulin concentrations increased by 1 h (4.6 +/- 0.90 vs. 7.4 +/- 0.91 microIU/mL for 0 and 1 h, respectively) and P4 concentrations decreased by 3 h (1.8 +/- 0.12 vs. 1.2 +/- 0.11 ng/mL for 0 and 3 h, respectively) after supplements were offered. In experiment 2, insulin concentrations were greater in cows fed high-moisture corn compared with those fed coarsely or finely ground corn (8.8 +/- 1.05, 5.7 +/- 1.05, and 6.1 +/- 1.05 micro

  14. High-resolution continuum source electrothermal atomic absorption spectrometry: Linearization of the calibration curves within a broad concentration range

    Energy Technology Data Exchange (ETDEWEB)

    Katskov, Dmitri, E-mail: katskovda@tut.ac.za [Tshwane University of Technology, Chemistry Department, Pretoria 0001 (South Africa); Hlongwane, Miranda [Tshwane University of Technology, Chemistry Department, Pretoria 0001 (South Africa); Heitmann, Uwe [German Aerospace Center, Rose-Luxemburg Str. 2, 10178 Berlin (Germany); Florek, Stefan [ISAS-Leibniz-Institut fuer Analytische Wissenschaften e.V., Albert-Einstein-Str. 9,12489 Berlin (Germany)

    2012-05-15

    The calculation algorithm suggested provides linearization of the calibration curves in high-resolution continuum source electrothermal atomic absorption spectrometry. The algorithm is based on the modification of the function wavelength-integrated absorbance vs. concentration of analyte vapor in the absorption volume. According to the suggested approach, the absorption line is represented by a triangle for low and trapezium for high analyte vapor concentration in the absorption volume. The respective semi-empirical formulas include two linearization parameters, which depend on properties of the absorption line and characteristics of the atomizer and spectrometer. The parameters can be approximately evaluated from the theory and determined in practice from the original broad-range calibration curve. The parameters were found and the proposed calculation algorithm verified in the experiments on direct determination of Ag, Cd, Cu, Fe, Mn and Pb in the solutions within a concentration ranges from 0.15 to 625 {mu}g{center_dot}L{sup -1} using tube, platform tube and filter furnace atomizers. The use of various atomizers, lines, elements and atomization temperatures made possible the simulation of various practical analytical conditions. It was found that the algorithm and optimal linearization parameters made it possible to obtain for each line and atomizer linear approximations of the calibration curves within 3-4 orders of magnitude with correlation coefficients close to 0.999. The algorithm makes possible to employ a single line for the direct element determination over a broad concentration range. The sources of errors and the possibility of a priori theoretical evaluation of the linearization parameters are discussed. - Highlights: Black-Right-Pointing-Pointer New calculation algorithm for HR-CS ET AAS measurements was proposed and applied. Black-Right-Pointing-Pointer The suggested formulas include two parameters to be determined experimentally. Black

  15. ZVI-Clay remediation of a chlorinated solvent source zone, Skuldelev, Denmark: 2. Groundwater contaminant mass discharge reduction

    DEFF Research Database (Denmark)

    Fjordbøge, Annika Sidelmann; Lange, Ida Vedel; Bjerg, Poul Løgstrup

    2012-01-01

    The impact of source mass depletion on the down-gradient contaminant mass discharge was monitored for a 19-month period as a part of a field demonstration of the ZVI-Clay soil mixing remediation technology. Groundwater samples were collected from conventional monitoring wells (120 samples) and a ...... down-gradient contaminant mass discharge reduction (76%) for the parent compound (PCE), while the overall reduction of chlorinated ethenes was smaller (21%)....

  16. Biocides in urban wastewater treatment plant influent at dry and wet weather: concentrations, mass flows and possible sources

    DEFF Research Database (Denmark)

    Bollmann, Ulla E.; Petersen, Camilla Tang; Eriksson, Eva

    2014-01-01

    in Denmark and Sweden during dry and wet weather. It was discovered, that biocides are detectable not only during wet weather but also during dry weather when leaching from façade coatings can be excluded as source. In most cases, the concentrations during dry weather were in the same range as during wet...... to 116 mg h(-1) carbendazim or 73 mg h(-1) mecoprop) supporting the hypothesis that the biocides were washed off by wind driven rain. Contrary, the biocide emissions during dry weather were rather related to household activities than with emissions from buildings, i.e., emissions were highest during...... morning and evening hours (up to 50 mg h(-1)). Emissions during night were significantly lower than during daytime. Only for propiconazole a different emission behaviour during dry weather was observed: the mass load peaked in the late afternoon (3 g h(-1)) and declined slowly afterwards. Most likely...

  17. Comparing exposure zones by different exposure metrics using statistical parameters: contrast and precision.

    Science.gov (United States)

    Park, Ji Young; Ramachandran, Gurumurthy; Raynor, Peter C; Eberly, Lynn E; Olson, Greg

    2010-10-01

    Recently, the appropriateness of using the 'mass concentration' metric for ultrafine particles has been questioned and surface area (SA) or number concentration metrics has been proposed as alternatives. To assess the abilities of various exposure metrics to distinguish between different exposure zones in workplaces with nanoparticle aerosols, exposure concentrations were measured in preassigned 'high-' and 'low-'exposure zones in a restaurant, an aluminum die-casting factory, and a diesel engine laboratory using SA, number, and mass concentration metrics. Predetermined exposure classifications were compared by each metric using statistical parameters and concentration ratios that were calculated from the different exposure concentrations. In the restaurant, SA and fine particle number concentrations showed significant differences between the high- and low-exposure zones and they had higher contrast (the ratio of between-zone variance to the sum of the between-zone and within-zone variances) than mass concentrations. Mass concentrations did not show significant differences. In the die cast facility, concentrations of all metrics were significantly greater in the high zone than in the low zone. SA and fine particle number concentrations showed larger concentration ratios between the high and low zones and higher contrast than mass concentrations. None of the metrics were significantly different between the high- and low-exposure zones in the diesel engine laboratory. The SA and fine particle number concentrations appeared to be better at differentiating exposure zones and finding the particle generation sources in workplaces generating nanoparticles. Because the choice of an exposure metric has significant implications for epidemiologic studies and industrial hygiene practice, a multimetric sampling approach is recommended for nanoparticle exposure assessment.

  18. Contribution of various carbon sources toward isoprene biosynthesis in poplar leaves mediated by altered atmospheric CO2 concentrations.

    Directory of Open Access Journals (Sweden)

    Amy M Trowbridge

    Full Text Available Biogenically released isoprene plays important roles in both tropospheric photochemistry and plant metabolism. We performed a (13CO(2-labeling study using proton-transfer-reaction mass spectrometry (PTR-MS to examine the kinetics of recently assimilated photosynthate into isoprene emitted from poplar (Populus × canescens trees grown and measured at different atmospheric CO(2 concentrations. This is the first study to explicitly consider the effects of altered atmospheric CO(2 concentration on carbon partitioning to isoprene biosynthesis. We studied changes in the proportion of labeled carbon as a function of time in two mass fragments, M41(+, which represents, in part, substrate derived from pyruvate, and M69(+, which represents the whole unlabeled isoprene molecule. We observed a trend of slower (13C incorporation into isoprene carbon derived from pyruvate, consistent with the previously hypothesized origin of chloroplastic pyruvate from cytosolic phosphenolpyruvate (PEP. Trees grown under sub-ambient CO(2 (190 ppmv had rates of isoprene emission and rates of labeling of M41(+ and M69(+ that were nearly twice those observed in trees grown under elevated CO(2 (590 ppmv. However, they also demonstrated the lowest proportion of completely labeled isoprene molecules. These results suggest that under reduced atmospheric CO(2 availability, more carbon from stored/older carbon sources is involved in isoprene biosynthesis, and this carbon most likely enters the isoprene biosynthesis pathway through the pyruvate substrate. We offer direct evidence that extra-chloroplastic rather than chloroplastic carbon sources are mobilized to increase the availability of pyruvate required to up-regulate the isoprene biosynthesis pathway when trees are grown under sub-ambient CO(2.

  19. Sources

    International Nuclear Information System (INIS)

    Duffy, L.P.

    1991-01-01

    This paper discusses the sources of radiation in the narrow perspective of radioactivity and the even narrow perspective of those sources that concern environmental management and restoration activities at DOE facilities, as well as a few related sources. Sources of irritation, Sources of inflammatory jingoism, and Sources of information. First, the sources of irritation fall into three categories: No reliable scientific ombudsman to speak without bias and prejudice for the public good, Technical jargon with unclear definitions exists within the radioactive nomenclature, and Scientific community keeps a low-profile with regard to public information. The next area of personal concern are the sources of inflammation. This include such things as: Plutonium being described as the most dangerous substance known to man, The amount of plutonium required to make a bomb, Talk of transuranic waste containing plutonium and its health affects, TMI-2 and Chernobyl being described as Siamese twins, Inadequate information on low-level disposal sites and current regulatory requirements under 10 CFR 61, Enhanced engineered waste disposal not being presented to the public accurately. Numerous sources of disinformation regarding low level radiation high-level radiation, Elusive nature of the scientific community, The Federal and State Health Agencies resources to address comparative risk, and Regulatory agencies speaking out without the support of the scientific community

  20. Evaluating vertical concentration profile of carbon source released from slow-releasing carbon source tablets and in situ biological nitrate denitrification activity

    Science.gov (United States)

    Yeum, Y.; HAN, K.; Yoon, J.; Lee, J. H.; Song, K.; Kang, J. H.; Park, C. W.; Kwon, S.; Kim, Y.

    2017-12-01

    Slow-releasing carbon source tablets were manufactured during the design of a small-scale in situ biological denitrification system to reduce high-strength nitrate (> 30 mg N/L) from a point source such as livestock complexes. Two types of slow-releasing tablets, precipitating tablet (PT, apparent density of 2.0 g/mL) and floating tablet (FT), were prepared to achieve a vertically even distribution of carbon source (CS) in a well and an aquifer. Hydroxypropyl methylcellulose (HPMC) was used to control the release rate, and microcrystalline cellulose pH 101 (MCC 101) was added as a binder. The #8 sand was used as a precipitation agent for the PTs, and the floating agents for the FTs were calcium carbonate and citric acid. FTs floated within 30 min. and remained in water because of the buoyance from carbon dioxide, which formed during the acid-base reaction between citric acid and calcium carbonate. The longevities of PTs with 300 mg of HPMC and FTs with 400 mg of HPMC were 25.4 days and 37.3 days, respectively. We assessed vertical CS profile in a continuous flowing physical aquifer model (release test, RT) and its efficiency on biological nitrate denitrification (denitrification test, DT). During the RT, PTs, FTs and a tracer (as 1 mg rhodamine B/L) were initially injected into a well of physical aquifer model (PAM). Concentrations of CS and the tracer were monitored along the streamline in the PAM to evaluate vertical profile of CS. During the DT, the same experiment was performed as RT, except continuous injection of solution containing 30 mg N/L into the PAM to evaluate biological denitrification activity. As a result of RT, temporal profiles of CS were similar at 3 different depths of monitoring wells. These results suggest that simultaneous addition of PT and FT be suitable for achieving a vertically even distribution of the CS in the injection well and an aquifer. In DT, similar profile of CS was detected in the injection well, and nitrate was biologically

  1. Air toxics concentrations, source identification, and health risks: An air pollution hot spot in southwest Memphis, TN

    Science.gov (United States)

    Jia, Chunrong; Foran, Jeffery

    2013-12-01

    Southwest Memphis is a residential region surrounded by fossil fuel burning, steel, refining, and food processing industries, and considerable mobile sources whose emissions may pose adverse health risks to local residents. This study characterizes cancer and non-cancer risks resulting from exposure to ambient air toxics in southwest Memphis. Air toxics samples were collected at a central location every 6 days from June 5, 2008 to January 8, 2010. Volatile organic compounds (VOCs) were collected in evacuated stainless-steel canisters and aldehydes by DNPH cartridges, and samples were analyzed for 73 target compounds. A total of 60 compounds were detected and 39 were found in over 86% of the samples. Mean concentrations of many compounds were higher than those measured in many industrial communities throughout the U.S. The cumulative cancer risk associated with exposure to 13 carcinogens found in southwest Memphis air was 2.3 × 10-4, four times higher than the national average of 5.0 × 10-5. Three risk drivers were identified: benzene, formaldehyde, and acrylonitrile, which contributed 43%, 19%, and 14% to the cumulative risk, respectively. This is the first field study to confirm acrylonitrile as a potential risk driver. Mobile, secondary, industrial, and background sources contributed 57%, 24%, 14%, and 5% of the risk, respectively. The results of this study indicate that southwest Memphis, a region of significant income, racial, and social disparities, is also a region under significant environmental stress compared with surrounding areas and communities.

  2. Differences in staining intensities affect reported occurrences and concentrations of Giardia spp. in surface drinking water sources.

    Science.gov (United States)

    Alderisio, K A; Villegas, L F; Ware, M W; McDonald, L A; Xiao, L; Villegas, E N

    2017-12-01

    USEPA Method 1623, or its equivalent, is currently used to monitor for protozoan contamination of surface drinking water sources worldwide. At least three approved staining kits used for detecting Cryptosporidium and Giardia are commercially available. This study focuses on understanding the differences among staining kits used for Method 1623. Merifluor and EasyStain labelling kits were used to monitor Cryptosporidium oocyst and Giardia cyst densities in New York City's raw surface water sources. In the year following a change to the approved staining kits for use with Method 1623, an anomaly was noted in the occurrence of Giardia cysts in New York City's raw surface water. Specifically, Merifluor-stained samples had higher Giardia cyst densities as compared with those stained with EasyStain. Side by side comparison revealed significantly lower fluorescence intensities of Giardia muris as compared with Giardia duodenalis cysts when labelled with EasyStain. This study showed very poor fluorescence intensity signals by EasyStain on G. muris cysts resulting in lower cyst counts, while Merifluor, with its broader Giardia cyst staining specificity, resulted in higher cyst counts, when using Methods 1623. These results suggest that detected Giardia cyst concentrations are dependent on the staining kits used, which can result in a more or less conservative estimation of occurrences and densities of zoonotic Giardia cysts by detecting a broader range of Giardia species/Assemblages. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

  3. Re-Os isotope and platinum group elements of a FOcal ZOne mantle source, Louisville Seamounts Chain, Pacific ocean

    Science.gov (United States)

    Tejada, Maria Luisa G.; Hanyu, Takeshi; Ishikawa, Akira; Senda, Ryoko; Suzuki, Katsuhiko; Fitton, Godfrey; Williams, Rebecca

    2015-02-01

    The Louisville Seamount Chain (LSC) is, besides the Hawaiian-Emperor Chain, one of the longest-lived hotspot traces. We report here the first Re-Os isotope and platinum group element (PGE) data for Canopus, Rigil, and Burton Guyots along the chain, which were drilled during IODP Expedition 330. The LSC basalts possess (187Os/188Os)i = 0.1245-0.1314 that are remarkably homogeneous and do not vary with age. A Re-Os isochron age of 64.9 ± 3.2 Ma was obtained for Burton seamount (the youngest of the three seamounts drilled), consistent with 40Ar-39Ar data. Isochron-derived initial 187Os/188Os ratio of 0.1272 ± 0.0008, together with data for olivines (0.1271-0.1275), are within the estimated primitive mantle values. This (187Os/188Os)i range is similar to those of Rarotonga (0.124-0.139) and Samoan shield (0.1276-0.1313) basalts and lower than those of Cook-Austral (0.136-0.155) and Hawaiian shield (0.1283-0.1578) basalts, suggesting little or no recycled component in the LSC mantle source. The PGE data of LSC basalts are distinct from those of oceanic lower crust. Variation in PGE patterns can be largely explained by different low degrees of melting under sulfide-saturated conditions of the same relatively fertile mantle source, consistent with their primitive mantle-like Os and primordial Ne isotope signatures. The PGE patterns and the low 187Os/188Os composition of LSC basalts contrast with those of Ontong Java Plateau (OJP) tholeiites. We conclude that the Re-Os isotope and PGE composition of LSC basalts reflect a relatively pure deep-sourced common mantle sampled by some ocean island basalts but is not discernible in the composition of OJP tholeiites.

  4. Effects of annealing gas and drain doping concentration on electrical properties of Ge-source/Si-channel heterojunction tunneling FETs

    Science.gov (United States)

    Bae, Tae-Eon; Wakabayashi, Yuki; Nakane, Ryosho; Takenaka, Mitsuru; Takagi, Shinichi

    2018-04-01

    Improvement in the performance of Ge-source/Si-channel heterojunction tunneling FETs (TFETs) with high on-current/off-current (I on/I off) ratio and steep subthreshold swing (SS) is demonstrated. In this paper, we experimentally examine the effects of gas ambient [N2 and forming gas (4% H2/N2)] and a doping concentration in the drain regions on the electrical characteristics of Ge/Si heterojunction TFETs. The minimum SS (SSmin) of 70.9 mV/dec and the large I on/I off ratio of 1.4 × 107 are realized by postmetallization annealing in forming gas. Also, the steep SSmin and averaged SS (SSavr) values of 64.2 and 78.4 mV/dec, respectively, are obtained in low drain doping concentration. This improvement is attributable to the reduction in interface state density (D it) in the channel region and to the low leakage current in the drain region.

  5. Large Industrial Point Sources in Italy: a focus on mercury concentrations resulting from three seasonal ship-borne measurements

    Directory of Open Access Journals (Sweden)

    Bencardino M.

    2013-04-01

    Full Text Available In Italy there are 25 Large Industrial Point Sources whose mercury emissions in air exceed the established threshold of 10 kg year−1. Many of these mercury point sources, mostly distributed along the Italian coastal area, are located at sites qualified as National Interest Rehabilitation Sites because of documented contamination in qualitative and/or quantitative terms and of potential health impact. Atmospheric mercury emissions related to Italian Large Industrial Point Sources, with a value of 1.04 Mg·yr−1 for 2007, have a not negligible contribution, accounting, on their own, for more than 10% of the total mercury emissions resulting from all activity sectors at a national level. Among others, thermal power stations, pig iron and steel as well as basic inorganic chemical production, result to be the main contributing industrial activities. In order to assess how mercury species concentrations and distribution in the Marine Boundary Layer (MBL change with vicinity to large industrial sites, measurements of atmospheric mercury were performed during three oceanographic campaigns aboard the Research Vessel (R.V. Urania of the Italian CNR. Collection of GEM, GOM and PBM was conducted across the Adriatic sea, during autumn 2004 (27th of October to 12th of November and summer 2005 (17th to 29th of June, and across the Tyrrhenian sea during autumn 2007 (12th of September to 1st October. Analysis were carried out with reference to the period in which the R.V. Urania has stopped close to the main Italian industrial contaminated sites. Explorative statistical parameters of atmospheric mercury species were computed over each single stop-period and then compared with the overall cruise campaign measurements. Results are herein presented and discussed.

  6. Growth Kinetics of Diazotrophic Bacillus sphaericus UPMB10 Cultured Using Different Types and Concentrations of Carbon and Nitrogen Sources

    Directory of Open Access Journals (Sweden)

    Ooi, T. C.

    2008-01-01

    Full Text Available Growth kinetics of newly isolated diazotrophic Bacillus sphaericus UPMB10 grown in various carbon (lactate, acetate, glycerol, malate, fructose, xylose and sucrose and nitrogen (glutamate, yeast extract, arginine, hystadine, glycine, polypeptone, tryptophan, lysine, NH4Cl and urea sources was investigated using 2 L stirred tank fermenter. The highest growth was obtained in a medium containing lactate as a carbon source, which gave the highest maximum cell concentration of 2.30 g/L, which is corresponding to maximum viable cell count of 4.60 x 10^9 cfu/mL. However, the highest cell yield (1.06 g cell/g carbon consumed was obtained in cultivation using glycerol though slightly lower maximum viable cell count was obtained (3.22 x 10^9 cfu/mL. In addition, cost for the production of live cell using glycerol was about 15 times lower than the cost using lactate. Growth performance of this bacterium when yeast extract was used as a nitrogen source was comparable to the use of pure amino acid. The medium containing 1.8 g/L glycerol and 2 g/L yeast extract was suggested as optimal for growth of this bacterium, which gave carbon to nitrogen ratio (C/N of 10:1. The maximum viable cell count obtained in cultivation using optimised medium in 2 L stirred tank fermenter was 3.34 x 10^9 cfu/mL and the cells maintained its capacity for N2 fixation at 18 nmol C2H2/h.mL.

  7. Commerce geophysical lineament - Its source, geometry, and relation to the Reelfoot rift and New Madrid seismic zone

    Science.gov (United States)

    Langenheim, V.E.; Hildenbrand, T.G.

    1997-01-01

    The Commerce geophysical lineament is a northeast-trending magnetic and gravity feature that extends from central Arkansas to southern Illinois over a distance of ???400 km. It is parallel to the trend of the Reelfoot graben, but offset ???40 km to the northwest of the western margin of the rift floor. Modeling indicates that the source of the aeromagnetic and gravity anomalies is probably a mafic dike swarm. The age of the source of the Commerce geophysical lineament is not known, but the linearity and trend of the anomalies suggest a relationship with the Reelfoot rift, which has undergone episodic igneous activity. The Commerce geophysical lineament coincides with several topographic lineaments, movement on associated faults at least as young as Quaternary, and intrusions of various ages. Several earthquakes (Mb > 3) coincide with the Commerce geophysical lineament, but the diversity of associated focal mechanisms and the variety of surface structural features along the length of the Commerce geophysical lineament obscure its relation to the release of present-day strain. With the available seismicity data, it is difficult to attribute individual earthquakes to a specific structural lineament such as the Commerce geophysical lineament. However, the close correspondence between Quaternary faulting and present-day seismicity along the Commerce geophysical lineament is intriguing and warrants further study.

  8. Characteristic groundwater level regimes in the capture zones of radial collector wells and importance of identification (Case study of Belgrade Groundwater Source

    Directory of Open Access Journals (Sweden)

    Božović Đorđije

    2016-01-01

    Full Text Available Assessment of the operating modes of radial collector wells reveals that the pumping levels in the well caissons are very low relative to the depth/elevation of the laterals, which is a common occurrence at Belgrade Groundwater Source. As a result, well discharge capacities vary over a broad range and groundwater levels in the capture zones differ even when the rate of discharge is the same. Five characteristic groundwater level regimes are identified and their origin is analyzed using representative wells as examples. The scope and type of background information needed to identify the groundwater level regime are presented and an interpretation approach is proposed for preliminary assessment of the aquifer potential at the well site for providing the needed amount of groundwater. [Projekat Ministarstva nauke Republike Srbije, br. OI176022, br. TR33039 i br. III43004

  9. Assessing the sources of the fishing down marine food web process in the Argentinean-Uruguayan Common Fishing Zone

    Directory of Open Access Journals (Sweden)

    Andrés J. Jaureguizar

    2008-03-01

    Full Text Available The temporal trend in the mean trophic level (mTL, fisheries-in-balance index (FIB, trophic categories landing (TrC and landing profile (LP of the exploited marine community (82 species in the Argentinean-Uruguayan Common Fishing Zone (AUCFZ were examined from 1989 to 2003. The total landings (Yt (rs=-0.561; P< 0.05 and the Yt of carnivores and top predators has declined, while the Yt of herbivores, detritivores and omnivores has increased. Consequently, the mTL significantly decreased (rs =-0.88; P< 0.01 at a rate of 0.41 from 1991 (mTL =3.81 to 2003 (mTL =3.4, and the FIB index has declined in the last 6 years. The LP temporal pattern showed four periods with significant differences in their species composition and Primary Production Required, which shows a strong decline in the traditional fishery resources (i.e. Merluccius hubbsi, Micropogonias furnieri, and increases in crustacean (Chaceon notilis, molluscs (Zygochlamys patagonica and some fishes (Macrodon ancylodon, Macruronus magallanicus, Rajidae. The mTL trend reflects the changes in the AUCFZ landing structure. This was characterized by large, slow-growing and late-maturing species during the early 1990s, while during recent years, early 2000s, it was mainly characterized by medium-sized fishes, crustaceans and molluscs. The examination of the mTL, FBI, TrC trajectories and LP temporal pattern suggests that new fishery resources are developing or that the fishing effort has been redistributed from overexploited resources to lightly exploited resources. In addition, the examination of discriminator and common species, and the fact that traditional resources are being over-fished support the hypothesis that the mTL trend has been influenced more by the impacts of new fishing technologies than the changes in market-driven exploitation and environmental fluctuation. These results provide evidence of the fishing down process along AUCFZ.

  10. Cornell Mixing Zone Expert System

    Science.gov (United States)

    This page provides an overview Cornell Mixing Zone Expert System water quality modeling and decision support system designed for environmental impact assessment of mixing zones resulting from wastewater discharge from point sources

  11. Characteristics of the event mean concentration (EMCs) from rainfall runoff on mixed agricultural land use in the shoreline zone of the Yamuna River in Delhi, India

    Science.gov (United States)

    Sharma, Deepshikha; Gupta, Ruchi; Singh, Ram Karan; Kansal, Arun

    2012-03-01

    This paper is focused on the monitoring of the diffuse pollution characteristics from the agricultural land confining the River Yamuna in Delhi (capital of India). Agricultural fields surrounding the Yamuna river are direct nonpoint source of pollution impacting the river quality. The study includes watershed delineation for the River Yamuna using SWAT (2005) and land use classification for the city using GIS and remote sensing. Thereafter, the rainfall-runoff pollutant concentrations from the mixed agricultural land use were assessed for the 2006 and 2007 monsoon period (July-September). Runoff was measured using SCS method and grab samples of rainfall runoff were collected at three stations namely Old Delhi Railway Bridge (ODRB), Nizamuddin and Okhla bridge in Delhi. The samples were analysed for physico-chemical and biological parameters. Rainfall runoff and event mean concentrations (EMCs) for different water quality parameters were characterized and the effect of land use was analyzed. The average EMCs for BOD, COD, ammonia, nitrate, TKN, hardness, TDS, TSS, chlorides, sulfates, phosphate, fluorides and TC were 21.82 mg/L, 73.48 mg/L, 72.68 μg/L, 229.87 μg/L, 15.32 μg/L, 11.36 mg/L, 117.44 mg/L, 77.60 mg/L, 117.64 mg/L, 135.82 mg/L, 0.08 mg/L, 0.85 mg/L and 2,827.47 MPN/100 mL, respectively. The EMCs of TSS, nitrogen and its compounds, phosphate and BOD were high.

  12. sources

    Directory of Open Access Journals (Sweden)

    Shu-Yin Chiang

    2002-01-01

    Full Text Available In this paper, we study the simplified models of the ATM (Asynchronous Transfer Mode multiplexer network with Bernoulli random traffic sources. Based on the model, the performance measures are analyzed by the different output service schemes.

  13. Mixed moderate thermophilic bioleaching of Cu, Mo and Re from molybdenite concentrate: effects of silver ion, medium and energy sources

    Directory of Open Access Journals (Sweden)

    Hadi Abdollahi

    2017-12-01

    Full Text Available This study evaluates the effects of different additives such as silver ion, medium and energy sources on the efficiency of mixed moderate thermophilic bioleaching approach to extract Cu, Mo and Re from molybdenite concentrate containing 0.98% Cu, 1.56% Fe, 53.84% Mo, and 0.055% Re. Molybdenite was the major phase of Mo-bearing mineral and chalcopyrite, covellite and pyrite were distinguished as minor phases. The higher copper extraction was obtained in tests with silver additives in all types and quantities rather than tests without silver ion. Kinetic of copper dissolution varied in these experiments and depended on the types and amounts of silver, and other supplemented additives such as ferric ion. There was no clear difference in the copper extraction by various culture media and 100% of Cu was dissolved after 30 days of treatment, using 50 mg/L of silver nitrate as additives. In the best condition and without silver additives, maximum 60% of copper was extracted even in the presence of energy sources such as sulfur, ferrous and ferric ions. In the most effective test with initial pH 1.57, 50 mg/L silver nitrate, and 50 g/L ferric sulfate, 100% of copper was dissolved in less than a week with highest kinetics rate. Molybdenum and rhenium extraction had the same tends with redox potential graph. By increasing the redox potential to the 550-600mV, molybdenite started to dissolve and finally, molybdenum and rhenium were extracted 2% and 9.53% in the best condition; respectively.

  14. Emissions of volatile organic compounds (VOCs) from concentrated animal feeding operations (CAFOs): chemical compositions and separation of sources

    Science.gov (United States)

    Yuan, Bin; Coggon, Matthew M.; Koss, Abigail R.; Warneke, Carsten; Eilerman, Scott; Peischl, Jeff; Aikin, Kenneth C.; Ryerson, Thomas B.; de Gouw, Joost A.

    2017-04-01

    Concentrated animal feeding operations (CAFOs) emit a large number of volatile organic compounds (VOCs) to the atmosphere. In this study, we conducted mobile laboratory measurements of VOCs, methane (CH4) and ammonia (NH3) downwind of dairy cattle, beef cattle, sheep and chicken CAFO facilities in northeastern Colorado using a hydronium ion time-of-flight chemical-ionization mass spectrometer (H3O+ ToF-CIMS), which can detect numerous VOCs. Regional measurements of CAFO emissions in northeastern Colorado were also performed using the NOAA WP-3D aircraft during the Shale Oil and Natural Gas Nexus (SONGNEX) campaign. Alcohols and carboxylic acids dominate VOC concentrations and the reactivity of the VOCs with hydroxyl (OH) radicals. Sulfur-containing and phenolic species provide the largest contributions to the odor activity values and the nitrate radical (NO3) reactivity of VOC emissions, respectively. VOC compositions determined from mobile laboratory and aircraft measurements generally agree well with each other. The high time-resolution mobile measurements allow for the separation of the sources of VOCs from different parts of the operations occurring within the facilities. We show that the emissions of ethanol are primarily associated with feed storage and handling. Based on mobile laboratory measurements, we apply a multivariate regression analysis using NH3 and ethanol as tracers to determine the relative importance of animal-related emissions (animal exhalation and waste) and feed-related emissions (feed storage and handling) for different VOC species. Feed storage and handling contribute significantly to emissions of alcohols, carbonyls, carboxylic acids and sulfur-containing species. Emissions of phenolic species and nitrogen-containing species are predominantly associated with animals and their waste.

  15. Polycyclic aromatic hydrocarbons (PAHs) concentration levels, pattern, source identification and soil toxicity assessment in urban traffic soil of Dhanbad, India.

    Science.gov (United States)

    Suman, Swapnil; Sinha, Alok; Tarafdar, Abhrajyoti

    2016-03-01

    Present study was carried out to assess and understand potential health risk and to examine the impact of vehicular traffic on the contamination status of urban traffic soils in Dhanbad City with respect to polycyclic aromatic hydrocarbons (PAHs). Eight urban traffic sites and two control/rural site surface soils were analyzed and the contents of 13 priority PAHs was determined. Total PAH concentration at traffic sites ranged from 1.019 μg g(-1) to 10.856 μg g(-1) with an average value of 3.488 μg g(-1). At control/rural site, average concentration of total PAHs was found to be 0.640 μg g(-1). PAH pattern was dominated by four- and five-ring PAHs (contributing >50% to the total PAHs) at all the eight traffic sites. On the other hand, rural soil showed a predominance of low molecular weight three-ring PAHs (contributing >30% to the total PAHs). Indeno[123-cd]pyrene/benz[ghi]perylene (IP/BgP) ratio indicated that PAH load at the traffic sites is predominated by the gasoline-driven vehicles. The ratio of Ant/(Ant+Phe) varied from 0.03 to 0.44, averaging 0.10; Fla/(Fla+Pyr) from 0.39 to 0.954, averaging 0.52; BaA/(BaA+Chry) from 0.156 to 0.60, averaging 0.44; and IP/(IP+BgP) from 0.176 to 0.811, averaging 0.286. The results indicated that vehicular emission was the major source for PAHs contamination with moderate effect of coal combustion and biomass combustion. Carcinogenic potency of PAH load in traffic soil was nearly 6.15 times higher as compared to the control/rural soil. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Heat Damage Zones Created by Different Energy Sources Used in the Treatment of Benign Prostatic Hyperplasia in a Pig Liver Model.

    Science.gov (United States)

    Kan, Chi Fai; Chan, Alexander Chak Lam; Pun, Chung Ting; Ho, Lap Yin; Chan, Steve Wai-Hee; Au, Wing Hang

    2015-06-01

    There are different types of transurethral prostatic surgeries and the complication profiles are different. This study aims to compare the heat damage zones (HDZ) created by five different technologies in a pig liver model. Monopolar resection, bipolar resection, electrovaporization, and Greenlight™ lasers of 120 and 180 W were used to remove fresh pig liver tissue in a simulated model. Each procedure was repeated in five specimens. Two blocks were selected from each specimen to measure the three deepest HDZ. The mean of HDZ was 295, 234, 192, 673, and 567 μm, respectively, for monopolar resection, bipolar resection, electrovaporization, Greenlight laser 120 W, and Greenlight laser 180 W, respectively. The Greenlight laser produced one to three times deeper HDZ than the other energy sources (p=0.000). Both 120 and 180 W Greenlight lasers produced deeper HDZ than the other energy sources. Urologists need to be aware of HDZ that cause tissue damage outside the operative field.

  17. [Attempt to reduce the formaldehyde concentration by blowing cooled fresh air down in to the breathing zone of medical students from an admission port on the ceiling during gross anatomy class].

    Science.gov (United States)

    Takayanagi, Masaaki; Sakai, Makoto; Ishikawa, Youichi; Murakami, Kunio; Kimura, Akihiko; Kakuta, Sachiko; Sato, Fumi

    2008-09-01

    Cadavers in gross anatomy laboratories at most medical schools are conventionally embalmed in formaldehyde solution, which is carcinogenic to humans. Medical students and instructors are thus exposed to formaldehyde vapors emitted from cadavers during dissection. To reduce high formaldehyde concentrations in the breathing zone above cadavers being examined by anatomy medical students provisionally, dissection beds were located under existing admission ports on the ceiling to supply cooled fresh air from the admission port blowing downward on to the cadaver. In all cases, compared to normal condition, the downward flow of cooled fresh air from an admission port reduced formaldehyde concentrations by 0.09-0.98 ppm and reduced to 12.6-65.4% in the air above a cadaver in the breathing zone of students. The formaldehyde concentrations above cadavers under admission ports were not more than the formaldehyde concentrations between beds representing the indoor formaldehyde concentrations. Although the application of an existing admission port on the ceiling in this study did not remove formaldehyde, the downflow of cooled fresh air using this system reduced the formaldehyde concentration in the air above cadavers being attended by anatomy students during dissections. These results suggest the need for reducing formaldehyde levels in gross anatomy laboratories using fundamental countermeasures in order to satisfy the guidelines of 0.08 ppm established by the World Health Organization and the Japan Ministry of Health, Labor and Welfare.

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

    Energy Technology Data Exchange (ETDEWEB)

    Quinn, J. J.; Environmental Science Division

    2006-12-22

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

  19. Analytical estimation of emission zone mean position and width in organic light-emitting diodes from emission pattern image-source interference fringes

    International Nuclear Information System (INIS)

    Epstein, Ariel; Tessler, Nir; Einziger, Pinchas D.; Roberts, Matthew

    2014-01-01

    We present an analytical method for evaluating the first and second moments of the effective exciton spatial distribution in organic light-emitting diodes (OLED) from measured emission patterns. Specifically, the suggested algorithm estimates the emission zone mean position and width, respectively, from two distinct features of the pattern produced by interference between the emission sources and their images (induced by the reflective cathode): the angles in which interference extrema are observed, and the prominence of interference fringes. The relations between these parameters are derived rigorously for a general OLED structure, indicating that extrema angles are related to the mean position of the radiating excitons via Bragg's condition, and the spatial broadening is related to the attenuation of the image-source interference prominence due to an averaging effect. The method is applied successfully both on simulated emission patterns and on experimental data, exhibiting a very good agreement with the results obtained by numerical techniques. We investigate the method performance in detail, showing that it is capable of producing accurate estimations for a wide range of source-cathode separation distances, provided that the measured spectral interval is large enough; guidelines for achieving reliable evaluations are deduced from these results as well. As opposed to numerical fitting tools employed to perform similar tasks to date, our approximate method explicitly utilizes physical intuition and requires far less computational effort (no fitting is involved). Hence, applications that do not require highly resolved estimations, e.g., preliminary design and production-line verification, can benefit substantially from the analytical algorithm, when applicable. This introduces a novel set of efficient tools for OLED engineering, highly important in the view of the crucial role the exciton distribution plays in determining the device performance.

  20. Analytical estimation of emission zone mean position and width in organic light-emitting diodes from emission pattern image-source interference fringes

    Energy Technology Data Exchange (ETDEWEB)

    Epstein, Ariel, E-mail: ariel.epstein@utoronto.ca; Tessler, Nir, E-mail: nir@ee.technion.ac.il; Einziger, Pinchas D. [Department of Electrical Engineering, Technion-Israel Institute of Technology, Haifa 32000 (Israel); Roberts, Matthew, E-mail: mroberts@cdtltd.co.uk [Cambridge Display Technology Ltd, Building 2020, Cambourne Business Park, Cambourne, Cambridgeshire CB23 6DW (United Kingdom)

    2014-06-14

    We present an analytical method for evaluating the first and second moments of the effective exciton spatial distribution in organic light-emitting diodes (OLED) from measured emission patterns. Specifically, the suggested algorithm estimates the emission zone mean position and width, respectively, from two distinct features of the pattern produced by interference between the emission sources and their images (induced by the reflective cathode): the angles in which interference extrema are observed, and the prominence of interference fringes. The relations between these parameters are derived rigorously for a general OLED structure, indicating that extrema angles are related to the mean position of the radiating excitons via Bragg's condition, and the spatial broadening is related to the attenuation of the image-source interference prominence due to an averaging effect. The method is applied successfully both on simulated emission patterns and on experimental data, exhibiting a very good agreement with the results obtained by numerical techniques. We investigate the method performance in detail, showing that it is capable of producing accurate estimations for a wide range of source-cathode separation distances, provided that the measured spectral interval is large enough; guidelines for achieving reliable evaluations are deduced from these results as well. As opposed to numerical fitting tools employed to perform similar tasks to date, our approximate method explicitly utilizes physical intuition and requires far less computational effort (no fitting is involved). Hence, applications that do not require highly resolved estimations, e.g., preliminary design and production-line verification, can benefit substantially from the analytical algorithm, when applicable. This introduces a novel set of efficient tools for OLED engineering, highly important in the view of the crucial role the exciton distribution plays in determining the device performance.

  1. Application of Emerging Open-source Embedded Systems for Enabling Low-cost Wireless Mini-observatory Nodes in the Coastal Zone

    Science.gov (United States)

    Glazer, B. T.

    2016-02-01

    Here, we describe the development of novel, low-cost, open-source instrumentation to enable wireless data transfer of biogeochemical sensors in the coastal zone. The platform is centered upon the Beaglebone Black single board computer. Process-inquiry in environmental sciences suffers from undersampling; enabling sustained and unattended data collection typically involves expensive instrumentation and infrastructure deployed as cabled observatories with little flexibility in deployment location following initial installation. High cost of commercially-available or custom electronic packages have not only limited the number of sensor node sites that can be targeted by reasonably well-funded academic researchers, but have also entirely prohibited widespread engagement with K-12, public non-profit, and `citizen scientist' STEM audiences. The new platform under development represents a balanced blend of research-grade sensors and low-cost open-source electronics that are easily assembled. Custom, robust, open-source code that remains customizable for specific node configurations can match a specific deployment's measurement needs, depending on the scientific research priorities. We have demonstrated prototype capabilities and versatility through lab testing and field deployments of multiple sensor nodes with multiple sensor inputs, all of which are streaming near-real-time data over wireless RF links to a shore-based base station. On shore, first-pass data processing QA/QC takes place and near-real-time plots are made available on the World Wide Web. Specifically, we have worked closely with an environmental and cultural management and restoration non-profit organization, and middle and high school science classes, engaging their interest in STEM application to local watershed processes. Ultimately, continued successful development of this pilot project can lead to a coastal oceanographic analogue of the popular Weather Underground personal weather station model.

  2. The Bolivian Source Rocks. Sub Andean Zone. Madre de Dios. Chaco Les roches mères de Bolivie. Subandin. Madre de Dios. Chaco

    Directory of Open Access Journals (Sweden)

    Diaz Martinez E.

    2006-11-01

    Full Text Available A complete study of source-rock geochemical data has been carried out for the Bolivian foothills and foreland (Sub Andean Zone, Chaco and Madre de Dios in order to quantify the petroleum potential of the area. Overall available data have been compiled in a database, and a synthesis of the results is presented here. Besides the classical mid-Devonian source rocks (Tequeje Fm in the north, Limoncito Fm in the center and Los Monos Fm in the south, others may be just as important : theTomachi Fm (late Devonian in the north of the country and the Copacabana Fm. (late Carboniferous-early Permian in the northern Sub Andean Zone. Both present an excellent potential with S2 up to 40 mg HC/g and average values larger than 10 mg HC/g on few hundred meters. The latest Cretaceous (Flora Fm in the northern Sub Andean Zone also presents locally a high potential but has almost no influence, its thickness being quite reduced. Almost all the source rocks matured during the Neogene due to the subsidence in the Andean foreland and, locally, in the piggyback basins, and are thus involved in the current petroleum system. Silurian and Lower Paleozoic units also contain thick shale beds, but these source rocks were mature before the Jurassic in most of the country, except in the Chaco, the Boomerang and the central Sub Andean Zone, where the Silurian is not nowadays overmature and may play an important role. The different zones are compared based on their Source Potential Index (SPI which indicates that the richest areas are the northern Sub Andean Zone and the Madre de Dios basin with SPI greater than 10 t/m². Since these two areas remain almost unexplored and, at least for the northern Sub Andean zone, present very large structures, these results allow to be optimistic about the possibilities for future exploration. Une base de données géochimiques a été mise en place entre 1994 et 1995 à YPFB (Yacimientos Petrolíferos Fiscales Bolivianos afin de regrouper les

  3. Numerical analysis of impurity separation from waste salt by investigating the change of concentration at the interface during zone refining process

    Science.gov (United States)

    Choi, Ho-Gil; Shim, Moonsoo; Lee, Jong-Hyeon; Yi, Kyung-Woo

    2017-09-01

    The waste salt treatment process is required for the reuse of purified salts, and for the disposal of the fission products contained in waste salt during pyroprocessing. As an alternative to existing fission product separation methods, the horizontal zone refining process is used in this study for the purification of waste salt. In order to evaluate the purification ability of the process, three-dimensional simulation is conducted, considering heat transfer, melt flow, and mass transfer. Impurity distributions and decontamination factors are calculated as a function of the heater traverse rate, by applying a subroutine and the equilibrium segregation coefficient derived from the effective segregation coefficients. For multipass cases, 1d solutions and the effective segregation coefficient obtained from three-dimensional simulation are used. In the present study, the topic is not dealing with crystal growth, but the numerical technique used is nearly the same since the zone refining technique was just introduced in the treatment of waste salt from nuclear power industry because of its merit of simplicity and refining ability. So this study can show a new application of single crystal growth techniques to other fields, by taking advantage of the zone refining multipass possibility. The final goal is to achieve the same high degree of decontamination in the waste salt as in zone freezing (or reverse Bridgman) method.

  4. Concentrating Radioactivity

    Science.gov (United States)

    Herrmann, Richard A.

    1974-01-01

    By concentrating radioactivity contained on luminous dials, a teacher can make a high reading source for classroom experiments on radiation. The preparation of the source and its uses are described. (DT)

  5. Effect of depositional environment and sources of pollution on uranium concentration in sediment, coral, algae and seagrass species from the Gulf of Aqaba (Red Sea)

    International Nuclear Information System (INIS)

    Abu-Hilal, A.H.

    1994-01-01

    Uranium concentrations were determined in sediment samples, four hard and two soft corals, one seagrass and four species of algae collected from phosphate-polluted sites in the northern reef area of the Gulf of Aqaba. High uranium concentrations were found in all samples examined from a phosphate-polluted site near a phosphate loading berth compared to the unpolluted ones. Uranium levels, U/Ca ratios, concentration and discrimination factors were also high compared to those reported from other regions of the world. The effects of the exported raw phosphate powder as the main source of pollution and depositional environment on the concentration of uranium in the examined species are discussed. (Author)

  6. Characteristics of radon concentration distributions measurement with two-filter method in the storage rooms of Ra-Be neutron source and the adjacent laboratories

    International Nuclear Information System (INIS)

    Liu Shuhuan; Chu Jun; Zhao Yaolin; Bao Lihong; Chen Wei; Wu Yuelei

    2012-01-01

    The basic principle of radon measurement with two-filter method is introduced in this paper. The levels of radon concentration in the storage rooms and the adjacent laboratories are measured and compared with the type of FT-648 radon measurement instrument. The measurement results showed that the levels of radon concentration in Ra-Be neutron source storage rooms are not higher than those in the adjacent laboratories, then it can be deduced that no radon gas was leaked out form the shielded and sealed Ra-Be neutron sources. The radon concentrations measured in the laboratories were near to the average level compared to the statistical results of the indoor dwellings' radon concentrations in Xi'an. The values didn't exceed the national standard limits(200 Bq·m -3 ). Furthermore, it is found that the radon concentration value measured at rainy or cloudy day is lesser than that at sunny day, and good ventilation conditions can effectively decrease the indoor radon concentration level. Meanwhile, the mechanisms of the radon concentration distributions in the laboratories influenced by the factors including various weather conditions (rainy, sunny and cloudy), ventilation and different measurement time periods in a day, etc. are primarily analyzed. The measurement results in this work provide some relative reference data for prediction the situations of Ra-Be neutron sources safety storage and experimenters' radiation protection in the laboratories. (authors)

  7. Identification sources of pollen spectra in dry and wet atmospheric deposition in the forest-steppe zone of Altai Krai (Russia)

    Science.gov (United States)

    Ryabchinskaya, Natalia; Nenasheva, Galina; Malygina, Natalia

    2015-04-01

    Pollen spectra circulating in the atmosphere contain the important information about primary biological aerosol particles (PBAP), worldwide interest in which has significantly increased in recent decades [Despres, 2012]. It is related to the fact that many researchers suggest primary aerosols as a condensation nucleus significantly affected on the formation of clouds and precipitation and, consequently, on the hydrological cycle and climate, especially at the regional level [Andreae et al., 2008; Poschlet et al., 2010; Prenni et al., 2009]. We present the comparison of pollen spectra obtained during the dry and wet atmospheric deposition in Altai Krai (Russia) and identification of the sources/regions of their receipts. Altai Krai is located in the center of the Eurasian continent, at the border of several natural and climatic zones. A significant part of the region's territory is characterized as a forest-steppe zone with a lot of natural and anthropogenic landscapes, accompanied by continental climate. It provides a rich diversity of natural vegetation and cultural associations. During last 10 years pollen grains has been monitored in the airspace of Barnaul city (the capital of Altai Krai) located in the central part of the forest-steppe zone). During the monitoring, the attempts to determine the origin of pollen spectra (local or introduced) were made as well. In the long-term average dates of the first wave of dusting in the spring season 2014 Burkard pollen traps were used in order to monitor the airspace in Barnaul, namely dry deposition of pollen grains [Nenasheva, 2013]. To estimate the wet deposition PBAP (pollen), which can reach 80% in the middle latitudes, precipitation sampler were installed close to Burkard pollen traps in order to sample precipitation. The samples were filtered through a filter having a pore diameter of 1 µm, then prepared and examined for the presence of pollen grains. The comparison of the results of pollen analysis of 10 samples

  8. Using nitrogen concentration and isotopic composition in lichens to spatially assess the relative contribution of atmospheric nitrogen sources in complex landscapes

    International Nuclear Information System (INIS)

    Pinho, P.; Barros, C.; Augusto, S.; Pereira, M.J.

    2017-01-01

    Reactive nitrogen (Nr) is an important driver of global change, causing alterations in ecosystem biodiversity and functionality. Environmental assessments require monitoring the emission and deposition of both the amount and types of Nr. This is especially important in heterogeneous landscapes, as different land-cover types emit particular forms of Nr to the atmosphere, which can impact ecosystems distinctively. Such assessments require high spatial resolution maps that also integrate temporal variations, and can only be feasibly achieved by using ecological indicators. Our aim was to rank land-cover types according to the amount and form of emitted atmospheric Nr in a complex landscape with multiple sources of N. To do so, we measured and mapped nitrogen concentration and isotopic composition in lichen thalli, which we then related to land-cover data. Results suggested that, at the landscape scale, intensive agriculture and urban areas were the most important sources of Nr to the atmosphere. Additionally, the ocean greatly influences Nr in land, by providing air with low Nr concentration and a unique isotopic composition. These results have important consequences for managing air pollution at the regional level, as they provide critical information for modeling Nr emission and deposition across regional as well as continental scales. - Highlights: • Which land-cover types are reactive nitrogen sources or sinks at a landscape level? • Nitrogen concentration and isotopic composition were analyzed in lichens. • This allowed determination of the main nitrogen sources: agricultural and urban areas. • Marine sources provided persistent low concentrations of reactive nitrogen. • The typical signature of each source was also determined. - Reactive-nitrogen concentration and isotopic composition in lichens were used to rank Nr sources at a landscape level.

  9. Relationship of the 2004 Mid-Niigata prefecture earthquake with geological structure. Evaluation of earthquake source fault in active folding zone

    International Nuclear Information System (INIS)

    Aoyagi, Yasuhira; Abe, Shintaro

    2007-01-01

    We compile the important points to evaluate earthquake source fault in active folding zone through a temporary aftershock observation of the 2004 Mid-Niigata Prefecture earthquake. The aftershock distribution shows spindle shape whose middle part is wide and both ends are narrow in NNE-SSW trending. The range of seismic activity corresponds well to the distribution of fold axes in this area, whose middle part is anticlinorium (some anticlines) and both ends are single anticline. In the middle part, the west dipping aftershock plane including the mainshock (M6.8) is located under the Higashiyama anticline. Another west dipping aftershock plane including the largest aftershock (M6.5) is located under the Tamugiyama and Komatsugura anticlines, and the east margin of the aftershock distribution corresponds well with Suwa-toge flexure. Therefore the present fold structure should have been formed by an accumulation of the same faults movement. In other words, it is important to refer the fold axes distribution pattern, especially with flexure, for the evaluation of earthquake source fault. In addition, we performed FEM analyses to investigate the relation of fold structure to the thickness of the sedimentary layer and the dip angle of the fault. Reverse fault movement forms asymmetric fold above the fault, which steeper slope is formed just above the upper end of the fault. As the sedimentary layer became thicker, anticline axis moved to hanging wall side in the fold structure. As the dip angle became smaller, the wavelength of the fold became longer and the fold structure grew highly asymmetric. Thus the shape of the fold structure is useful as an index to estimate the blind thrust below it. (author)

  10. Parametrics for Molecular Deuterium Concentrations in the Source Region of the UW-IEC Device Using an Ion Acoustic Wave Diagnostic

    Science.gov (United States)

    Boris, D. R.; Emmert, G. A.

    2007-11-01

    The ion source region of the UW-Inertial Electrostatic Confinement device is comprised of a filament assisted DC discharge plasma that exists between the wall of the IEC vacuum chamber and the grounded spherical steel grid that makes up the anode of the IEC device. A 0-dimensional rate equation calculation of the molecular deuterium ion species concentration has been applied utilizing varying primary electron energy, and neutral gas pressure. By propagating ion acoustic waves in the source region of the IEC device the concentrations of molecular deuterium ion species have been determined for these varying plasma conditions, and high D3^+ concentrations have been verified. This was done by utilizing the multi-species ion acoustic wave dispersion relation, which relates the phase speed of the multi-species ion acoustic wave, vph, to the sum in quadrature of the concentration weighted ion acoustic sound speeds of the individual ion species.

  11. Kinetics and Mechanisms of Phosphorus Adsorption in Soils from Diverse Ecological Zones in the Source Area of a Drinking-Water Reservoir.

    Science.gov (United States)

    Zhang, Liang; Loáiciga, Hugo A; Xu, Meng; Du, Chao; Du, Yun

    2015-11-10

    On-site soils are increasingly used in the treatment and restoration of ecosystems to harmonize with the local landscape and minimize costs. Eight natural soils from diverse ecological zones in the source area of a drinking-water reservoir in central China are used as adsorbents for the uptake of phosphorus from aqueous solutions. The X-ray fluorescence (XRF) spectrometric and BET (Brunauer-Emmett-Teller) tests and the Scanning Electron Microscopy (SEM) and Fourier Transform Infrared (FTIR) spectral analyses are carried out to investigate the soils' chemical properties and their potential changes with adsorbed phosphorous from aqueous solutions. The intra-particle diffusion, pseudo-first-order, and pseudo-second-order kinetic models describe the adsorption kinetic processes. Our results indicate that the adsorption processes of phosphorus in soils occurred in three stages and that the rate-controlling steps are not solely dependent on intra-particle diffusion. A quantitative comparison of two kinetics models based on their linear and non-linear representations, and using the chi-square (χ2) test and the coefficient of determination (r2), indicates that the adsorptive properties of the soils are best described by the non-linear pseudo-second-order kinetic model. The adsorption characteristics of aqueous phosphorous are determined along with the essential kinetic parameters.

  12. Processing of Bi2.1Sr1.8Ca1.1Cu2O8 source material for float-zone fiber growth

    International Nuclear Information System (INIS)

    Peszkin, P.N.; Raymakers, R.J.; Feigelson, R.S.; Moulton, L.V.; Lu, Z.

    1991-01-01

    Bi 2.1 Sr 1.8 Ca 1.1 Cu 2 O 8 fibers having excellent superconducting properties can be grown by a laser-heated float zone process. In order to maintain stable growth conditions and thereby obtain fibers free of diameter fluctuations and voids, dense ceramic starting material containing only the 2212 phase is required. In this study various processing parameters, including calcining and sintering temperatures and times, grain size of the powders used, and pressing pressures were optimized to yield dense, chemically homogeneous starting material. It was found that under most conditions there was no increase in the density on sintering. Retrograde densification was the usual situation except at higher pressures and was found to depend on pressing pressure, calcination history, and sintering temperature. Cold-pressing at higher pressures (100 000 psi) yielded denser but chemically inhomogeneous material. Ceramic samples sintered for long times (>48 h) yielded source rods that produced instabilities during fiber growth, presumably due to preferential loss of mass during sintering

  13. Impacts of different salt source and concentrations on germination and seedling growth of many pumpkin seeds used as rootstoch in Iran

    Directory of Open Access Journals (Sweden)

    Dadashpour Ahmad

    2012-01-01

    Full Text Available The effects of different salt sources (C Cl2, NaCl, and KCl and concentrations, as measured by electrical conductivity, (0, "control", 1, 3, 5, 7 and 9 dS m-1 on seed germination and seedling growth of “Ferro”, “Obez”, “RS 841” and “Strong Tosa F1” pumpkin varieties used as rootstock were investigated in this study. The results showed that germination rate, root length, shoot length, fresh root weight, dry root weight, fresh shoot weight and dry shoot weights tend to decrease when the electrical conductivity of the solution is higher than 5 dS m-1, independent of salt sources and in all of the varieties. Three days after seeding, a germination ratio of 5 % was obtained from RS 841 variety in all salt source and concentrations, while a germination ratio over 50 % was obtained in “Strong Tosa” variety for the same conditions except CaCl2 salt source. Nevertheless, seeds germinated in medium having high concentrations of CaCl2 had lower germination rate and poor seedling growth, compared to media having the same concentrations of NaCl and KCl. It was concluded that all of the varieties studied were more sensitive to the concentrations prepared using CaCl2 than that of the KCl, and NaCl.

  14. Effect of sediment composition on methane concentration and production in the transition zone of a mangrove (Sepetiba Bay, Rio de Janeiro, Brazil)

    OpenAIRE

    Marinho,CC.; Campos,EA.; Guimarães,JRD.; Esteves,FA.

    2012-01-01

    The aim of this research was to evaluate the effect of sediment composition on methane (CH4) dynamics in sediments of different areas in the transition zone between a mangrove and the sea. This research was conducted in a mangrove at Coroa Grande, on the southern coast of Rio de Janeiro. Samples were collected at three stations: (1) region colonised by Rhizophora mangle L. on the edge of the mangrove, (2) region colonised by seagrasses and (3) infra-littoral region without vegetation. Samples...

  15. Zoning and contamination rate of magnesium and heavy metals of iron, zinc and copper in the north and northwest aquifer of Khoy (Zourabad based on GIS and determining the contaminated source

    Directory of Open Access Journals (Sweden)

    Fariborz Khodadadi

    2015-04-01

    Full Text Available Introduction Heavy metals are the most toxic pollutants in aquatic ecosystems. This contamination can result from the release of heavy metal elements during alteration and weathering of ultramafic and mafic rocks (ophiolite zones. Among the important metals and pollutants in the ophiolite; chromium, cobalt, nickel, iron, magnesium, manganese, zinc and copper could be noted. Basically, a mass of serpentine consists of serpentine, amphibole, talc, chlorite, magnetite, and the remainder of olivine, pyroxene and spinel (Kil et al., 2010. In such areas, the prevailing cold climate, during the serpentinization, chloritization and epidotiization, the activity of the solvent, such as chloride, fluoride, carbonates, sulfide, sulfosalt would be able to import the elements such as magnesium and iron, copper and zinc into the soil and groundwater. The study area is located in northwestern Iran. This area is located in the northwest of the city of Khoy. Because of the proximity to the north and northwest Khoy plains with ophiolite rocks, the soil of this region could possibly show the potential of contamination with heavy metals. Due to the toxicity and disease of unauthorized grades of these elements in groundwater in the study area, this study is focused on the more contaminated groundwater of the areas. Materials and methods In this study, over a period of 5 days, sampling from 42 water sources, including fountains, aqueducts, wells, piezometers and wells in operation, was performed. The container was washed with acid and then rinsed 3 times with the water sample. The pH and temperature of the water in the samples was measured in the field. Then to each of the samples was taken from 2 to 5 ml of concentrated nitric acid (This causes that the metal elements would not adsorbed or precipitated by these particles and pH of the samples was measured with litmus paper to reach level 2. This was done to ensure the consolidation of the water samples. Analysis of

  16. Identification of sources of elevated concentrations of polycyclic aromatic hydrocarbons in an industrial area in Tianjin, China

    NARCIS (Netherlands)

    Jiao, W.T.; Lu, Y.L.; Li, J.; Han, Jingyi; Wang, T.Y.; Luo, W.; Shi, Y.J.; Wang, G.

    2009-01-01

    The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) were determined by gas chromatography equipped with a mass spectrometry detector in 105 topsoil samples from an industrial area around Bohai Bay, Tianjin in the North of China. Results demonstrated that concentrations of PAHs in 104

  17. Effect of Carbohydrate Source and Cottonseed Meal Level in the Concentrate on Feed Intake, Nutrient Digestibility, Rumen Fermentation and Microbial Protein Synthesis in Swamp Buffaloes

    Directory of Open Access Journals (Sweden)

    M. Wanapat

    2013-07-01

    Full Text Available The objective of this study was to investigate the effect of carbohydrate source and cottonseed meal level in the concentrate on feed intake, nutrient digestibility, rumen fermentation and microbial protein synthesis in swamp buffaloes. Four, 4-yr old rumen fistulated swamp buffaloes were randomly assigned to receive four dietary treatments according to a 2×2 factorial arrangement in a 4×4 Latin square design. Factor A was carbohydrate source; cassava chip (CC and CC+rice bran at a ratio 3:1 (CR3:1, and factor B was level of cottonseed meal (CM; 109 g CP/kg (LCM and 328 g CP/kg (HCM in isonitrogenous diets (490 g CP/kg. Buffaloes received urea-treated rice straw ad libitum and supplemented with 5 g concentrate/kg BW. It was found that carbohydrate source did not affect feed intake, nutrient intake, digested nutrients, nutrient digestibility, ammonia nitrogen concentration, fungi and bacterial populations, or microbial protein synthesis (p>0.05. Ruminal pH at 6 h after feeding and the population of protozoa at 4 h after feeding were higher when buffalo were fed with CC than in the CR3:1 treatment (p0.05. Based on this experiment, concentrate with a low level of cottonseed meal could be fed with cassava chips as an energy source in swamp buffalo receiving rice straw.

  18. A source-orientated approach for estimating daytime concentrations of biogenic volatile organic compounds in an upper layer of a boreal forest canopy

    Energy Technology Data Exchange (ETDEWEB)

    Lappalainen, H.K. [Finnish Meteorological Inst., Helsinki (Finland); Sevanto, S.; Dal Maso, M.; Taipale, R.; Kajos, M. [Helsinki Univ. (Finland). Dept. of Physics; Kolari, P.; Back, J. [Helsinki Univ. (Finland). Dept. of Forest Ecology Sciences

    2013-06-01

    Biologically justified statistical models for daytime atmospheric concentrations of methanol, acetaldehyde, acetone, isoprene and monoterpene were tested using measurements at a boreal forest stand in southern Finland in 2006-2007 and in summer 2008. The canopy-scale concentrations of all compounds except monotepene were closely correlated with shoot-scale concentrations indicating a strong link to biological emission source. All the models were based on the exponential relationship between air temperature and atmospheric concentration of biogenic volatile organic compounds (BVOCs). The first model - an exponential function of air temperature (T model) - could explain 27%-64% of the variation in BVOC daytime concentrations in the test data. The second model - a Temperature-State of Development model (T-S model) having two explaining variables (air temperature and seasonal photosynthetic efficiency) - was derived from an empirical adjustment of seasonality. This model slightly increased the fraction of explained variation but it still could not explain the high concentration peaks, which accounted for most of the unexplained variation. To better analyse these peaks we tested the Trigger model including two potential environmental triggers, a PAR index (high photosynthetically active photon flux density (PAR) and high ozone concentration, that could increase the concentrations momentarily. However, the Trigger model described the peak concentrations only somewhat better than the T or T-S model. It seems that it is very difficult to explain more than 32%-67% of variation in BVOC concentrations by a straightforward source-oriented modelling without deep understanding of biological and physical processes. In order to improve the models profound studies on specific stress factors and events inducing BVOC emissions are needed. (orig.)

  19. Distribution of gaseous and particle-bound Hg concentrations at the sites representative for urban and non-urban zones of Silesia Province

    Directory of Open Access Journals (Sweden)

    Pyta Halina

    2018-01-01

    Full Text Available The basic features of the distribution of total gaseous (TGM and particle-bound mercury (PBM concentrations were determined for a five locations representative for urban (Bielsko-Biała, Lubliniec, Zabrze and rural areas (Godów, Złoty Potok of Silesia Province. Gaseous mercury concentrations were measured (1 continuously - the automatic 1h TGM measurements in Zloty Potok and Zabrze and (2 non-continuously manual 24h TGM measurements with a pre-concentration of the Hg on gold traps (Bielsko-Biała, Lubliniec, Godów. The PBM concentrations were measured non-continuously by taking PM2.5 samples. The Hg content was determined by using a CVAAS method. The highest average concentration of TGM was recorded in Zabrze (2.8ng/m3, significantly lower (2.0ng/m3 in Bielsko-Biała and in the non-urban station in Godów, the lowest concentration (<2.0 ng/m3 was observed in Lubliniec and at the regional background station in Zloty Potok. The results obtained for TGM concentrations exceeded the European average level of 1.5 ng/m3 (AirBase, 2014. The highest average PBM concentration, associated with PM2.5, was obtained in Zabrze (70pg/m3, more than 20% lower results were obtained in Bielsko-Biała and Godów, finally, the lowest one (lower by about 40% in comparison with Zabrze were obtained in Lubliniec and Złoty Potok. Moreover, an enrichment of Hg concentration in PM was observed with the increasing of the PM content, during the heating season.

  20. Decreasing aqueous mercury concentrations to achieve safe levels in fish: examining the water-fish relationship in two point-source contaminated streams

    Energy Technology Data Exchange (ETDEWEB)

    Mathews, Teresa J [ORNL; Southworth, George R [ORNL; Peterson, Mark J [ORNL; Roy, W Kelly [ORNL; Ketelle, Richard H [ORNL; Valentine, Charles S [ORNL; Gregory, Scott M [ORNL

    2013-01-01

    East Fork Poplar Creek (EFPC) and White Oak Creek (WOC) are two mercury-contaminated streams located on the Department of Energy s Oak Ridge Reservation in east Tennessee. East Fork Poplar Creek is the larger and more contaminated of the two, with average aqueous mercury (Hg) concentrations exceeding those in reference streams by several hundred-fold. Remedial actions over the past 20 years have decreased aqueous Hg concentrations in EFPC by 85 %. Fish fillet concentrations, however, have not responded to this decrease in aqueous Hg and remain above the U.S. Environmental Protection Agency s ambient water quality criterion (AWQC) of 0.3 mg/kg. The lack of correlation between aqueous and fish tissue Hg concentrations in this creek has led to questions regarding the usefulness of target aqueous Hg concentrations and strategies for future remediation efforts. White Oak Creek has a similar contamination history but aqueous Hg concentrations in WOC are an order of magnitude lower than in EFPC. Despite the lower aqueous Hg concentrations, fish fillet concentrations in WOC have also been above the AWQC, making the most recent aqueous Hg target of 200 ng/L in EFPC seem unlikely to result in an effective decrease in fillet Hg concentrations. Recent monitoring efforts in WOC, however, suggest an aqueous total Hg threshold above which Hg bioaccumulation in fish may not respond. This new information could be useful in guiding remedial actions in EFPC and in other point-source contaminated streams.

  1. The effect of dietary cation-anion difference concentration and cation source on milk production and feed efficiency in lactating dairy cows.

    Science.gov (United States)

    Iwaniuk, M E; Weidman, A E; Erdman, R A

    2015-03-01

    Feed costs currently account for 55% or more of the total cost of milk production in US dairy herds, and dairy producers are looking for strategies to improve feed efficiency [FE; 3.5% fat-corrected milk (FCM) per dry matter (DM) intake]. Increasing dietary cation-anion difference [DCAD; Na+K-Cl (mEq/kg of DM)] has been shown to increase milk production, FCM, and FE. However, the optimal DCAD concentration for maximal FE has yet to be determined. The objectives of this research were to test the effects of DCAD concentration and cation source on dairy FE. Sixty Holstein dairy cows (20 cows per experiment) were used in three 4×4 Latin square design experiments with 3-wk experimental periods. In experiments 1 and 2, we tested the effect of DCAD concentration: cows were fed a basal diet containing ~250 mEq/kg of DM DCAD that was supplemented with potassium carbonate at 0, 50, 100, and 150 mEq/kg of DM or 0, 125, 250, and 375 mEq/kg of DM in experiments 1 and 2, respectively. In experiment 3, we tested the effect of cation source: sodium sesquicarbonate replaced 0, 33, 67, and 100% of the supplemental potassium carbonate (150 mEq/kg of DM DCAD). The DCAD concentration had no effect on milk production, milk protein concentration, or milk protein yield in experiments 1 and 2. Dry matter intake was not affected by DCAD concentration in experiment 1 or by cation source in experiment 3. However, DMI increased linearly with increasing DCAD in experiment 2. We detected a linear increase in milk fat concentration and yield with increasing DCAD in experiments 1 and 2 and by substituting sodium sesquicarbonate for potassium carbonate in experiment 3. Increased milk fat concentration with increasing DCAD led to increases in 3.5% FCM in experiments 1 and 2. Maximal dairy FE was achieved at a DCAD concentration of 426 mEq/kg of DM in experiments 1 and 2 and by substituting Na for K in experiment 3. The results of these experiments suggest that both DCAD concentration and the cation

  2. Design of a thermal neutron field by 252Cf source for measurement of 10B concentrations in the blood samples for BNCT

    International Nuclear Information System (INIS)

    Naito, H.; Sakurai, Y.; Maruhashi, A.

    2006-01-01

    10 B concentrations in the blood samples for BNCT has been estimated due to amounts of prompt gamma rays from 10 B in the fields of thermal neutrons from a special guide tube attached to research reactor. A system using radioisotopes as the source of thermal neutron fields has advantages that are convenient and low cost because it doesn't need running of a reactor or an accelerator. The validity of 252 Cf as a neutron source for 10 B concentrations detection system was investigated. This system is composed of D 2 O moderator, Pb reflector/filter, C reflector, and LiF filter. A thermal neutron field with low background gamma-rays is obtained. A large source of 252 Cf is required to obtain a sufficient flux. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Gerlach, Robin [Montana State Univ., Bozeman, MT (United States); Peyton, Brent M. [Montana State Univ., Bozeman, MT (United States); Apel, William A. [Idaho National Lab., Idaho Falls, ID (United States)

    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

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

    International Nuclear Information System (INIS)

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

    2014-01-01

    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

  5. Estimating Potential Increased Bladder Cancer Risk Due to Increased Bromide Concentrations in Sources of Disinfected Drinking Waters - slides

    Science.gov (United States)

    Public water systems are increasingly facing higher bromide levels in their source waters from anthropogenic contamination through coal-fired powerplants, conventional oil and gas extraction, and hydraulic fracturing. Climate change is likely to exacerbate this in coming years. W...

  6. Estimating Potential Increased Bladder Cancer Risk Due to Increased Bromide Concentrations in Sources of Disinfected Drinking Waters

    Science.gov (United States)

    Public water systems are increasingly facing higher bromide levels in their source waters from anthropogenic contamination through coal-fired power plants, conventional oil and gas extraction, and hydraulic fracturing. Climate change is likely to exacerbate this in coming years. ...

  7. Seasonal Variation of Arsenic Concentration in Natural Water of the Source Area of the Yellow River on the Qinghai-Tibet Plateau, China

    Science.gov (United States)

    Yu, C.; Wen, L.; Yu, Z.

    2017-12-01

    Seasonal variation in the arsenic (As) concentration of natural water has been studied the first time in the source area of the Yellow River (SAYR) in Tibet, China. Samples were collected in the lake, river and spring across the whole area in April (spring) and July (summer), 2014. In April the average values of arsenic concentration in SAYR from high to low were: lake (38.1μg/L, n=47, range 8.6-131.0μg/L) > river (24.3μg/L, n=83, range 4.3-77.1μg/L) > spring (19.1μg/L, n=12, range 12.0-29.4μg/L). In July the same order of the average values of arsenic concentration in SAYR was found: lake (14.1μg/L, n=57, range 5.8-68.5μg/L) > river (7.3μg/L, n=106, range 3.6-22.9μg/L)> spring (6.7μg/L, n=9, range 4.8-8.2μg/L).The average arsenic concentrations in April were almost three times higher than those in July. In both season, the higher concentrations of arsenic were distributed in the upper reaches above the two biggest lakes of Gyaring and Ngoring Lakes in SAYR. The two big lakes buffered the naturally generated arsenic concentration in surface water, suggesting the important ecological role of the lakes. Generally, the lower concentrations in July probably were due to 1. the dilution effect of the precipitation; 2 the change of water sources. In April when the permafrost and mountain snow started to thaw and melt, ground water with high arsenic concentration was the main water source with high concentration of arsenic; but in July, with the increase of the temperature, mountain snow, permafrost would contribute more than in April, in addition, the main arsenic contributor groundwater was diluted by the precipitation recharge. Since in spring, lake and river water arsenic concentration decreased with almost the same magnitude., assuming the dilution effect dominant. The exported arsenic from SAYR in April (903.4Kg) were twice more than it in July (449.1Kg), because the flowrates were similar in the two months, the water source of the runoff components was

  8. Comparison of PM10 concentrations and metal content in three different sites of the Venice Lagoon: an analysis of possible aerosol sources.

    Science.gov (United States)

    Contini, Daniele; Belosi, Franco; Gambaro, Andrea; Cesari, Daniela; Stortini, Angela Maria; Bove, Maria Chiara

    2012-01-01

    The Venice Lagoon is exposed to atmospheric pollutants from industrial activities, thermoelectric power plants, petrochemical plants, incinerator, domestic heating, ship traffic, glass factories and vehicular emissions on the mainland. In 2005, construction began on the mobile dams (MOSE), one dam for each channel connecting the lagoon to the Adriatic Sea as a barrier against high tide. These construction works could represent an additional source of pollutants. PM10 samples were taken on random days between 2007 and 2010 at three different sites: Punta Sabbioni, Chioggia and Malamocco, located near the respective dam construction worksites. Chemical analyses of V, Cr, Fe, Co, Ni, Cu, Zn, As, Mo, Cd, Sb, Tl and Pb in PM10 samples were performed by Inductively coupled plasma-quadrupole mass spectrometry (ICP-QMS) and results were used to identify the main aerosol sources. The correlation of measured data with meteorology, and source apportionment, failed to highlight a contribution specifically associated to the emissions of the MOSE construction works. The comparison of the measurements at the three sites showed a substantial homogeneity of metal concentrations in the area. Source apportionment with principal component analysis (PCA) and positive matrix factorization (PMF) showed that a four principal factors model could describe the sources of metals in PM10. Three of them were assigned to specific sources in the area and one was characterised as a source of mixed origin (anthropogenic and crustal). A specific anthropogenic source of PM10 rich in Ni and Cr, active at the Chioggia site, was also identified.

  9. Drying process of fermented inulin fiber concentrate by Bifidobacterium bifidum as a dietary fiber source for cholesterol binder

    Science.gov (United States)

    Susilowati, Agustine; Aspiyanto, Ghozali, Muhammad

    2017-11-01

    Fermentation on inulin hydrolysate as fructooligosaccharides (FOS) by Bifidobacterium bifidum as a result of hydrolysis by inulase enzyme of Scopulariopsis sp.-CBS1 fungi has been performed to bind cholesterol. Their applications on preparation of fermented pour beverages was conducted via a series of concentration process using dead-end Stirred Ultrafiltration Cell (SUFC) mode at stirrer rotation of 400 rpm, room temperature and pressure of 40 psia for 0 minute (pre-concentration process) as concentrate (A) and 45 minutes as concentrate (B), and drying process using vacuum dryer at 30 °C and 22 cm Hg for 0, 8, 16, 24, 32, 40 and 48 hours. Based on optimization of Total Dietary Fiber (TDF), the best time of drying process was achieved for 40 hours. Long time of drying process would increase TDF and total solids, decreased total acids, and fluctuated dissolved protein and Cholesterol Binding Capacity (CBC). At the optimum condition of drying process was get fermented inulin fiber powder from concentration processes using both UF as pre process (0 minute) as concentrate (A) and UF for 45 minutes as concentrate (B) with compositions of total solids of 92.31 % and 93.67 %, TDF of 59.07 % (dry weight) and 69.28 %, total acids of 7.03 % and 7.5 %, dissolved protein of 3.95 mg/mL and 3.05 mg/mL, and CBC pH 2 15.71 mg/g and 16.8 mg/g, respectively. Concentration process through dead-end SUFC mode gave distribution of particles with better smoothness level than without through dead-end SUFC mode.

  10. Spatial-temporal dynamics of NDVI and Chl-a concentration from 1998 to 2009 in the East coastal zone of China: integrating terrestrial and oceanic components.

    Science.gov (United States)

    Hou, Xiyong; Li, Mingjie; Gao, Meng; Yu, Liangju; Bi, Xiaoli

    2013-01-01

    Annual normalized difference vegetation index (NDVI) and chlorophyll-a (Chl-a) concentration are the most important large-scale indicators of terrestrial and oceanic ecosystem net primary productivity. In this paper, the Sea-viewing Wide Field-of-view Sensor level 3 standard mapped image annual products from 1998 to 2009 are used to study the spatial-temporal characters of terrestrial NDVI and oceanic Chl-a concentration on two sides of the coastline of China by using the methods of mean value (M), coefficient of variation (CV), the slope of unary linear regression model (Slope), and the Hurst index (H). In detail, we researched and analyzed the spatial-temporal dynamics, the longitudinal zonality and latitudinal zonality, the direction, intensity, and persistency of historical changes. The results showed that: (1) spatial patterns of M and CV between NDVI and Chl-a concentration from 1998 to 2009 were very different. The dynamic variation of terrestrial NDVI was much mild, while the variation of oceanic Chl-a concentration was relatively much larger; (2) distinct longitudinal zonality was found for Chl-a concentration and NDVI due to their hypersensitivity to the distance to shoreline, and strong latitudinal zonality existed for Chl-a concentration while terrestrial NDVI had a very weak latitudinal zonality; (3) overall, the NDVI showed a slight decreasing trend while the Chl-a concentration showed a significant increasing trend in the past 12 years, and both of them exhibit strong self-similarity and long-range dependence which indicates opposite future trends between land and ocean.

  11. Effect of vitamin E intake from food and supplement sources on plasma α- and γ-tocopherol concentrations in a healthy Irish adult population.

    Science.gov (United States)

    Zhao, Yang; Monahan, Frank J; McNulty, Breige A; Gibney, Mike J; Gibney, Eileen R

    2014-11-14

    Vitamin E is believed to play a preventive role in diseases associated with oxidative stress. The aims of the present study were to quantify vitamin E intake levels and plasma concentrations and to assess dietary vitamin E adequacy in Irish adults. Intake data from the National Adult Nutrition Survey were used; plasma samples were obtained from a representative cohort of survey participants. Plasma α- and γ-tocopherol concentrations were measured by HPLC. The main sources of vitamin E in the diet were 'butter, spreadable fats and oils' and 'vegetables and vegetable dishes'. When vitamin E intake from supplements was taken into account, supplements were found to be the main contributor, making a contribution of 29·2 % to vitamin E intake in the total population. Supplement consumers had significantly higher plasma α-tocopherol concentrations and lower plasma γ-tocopherol concentrations when compared with non-consumers. Consumers of 'vitamin E' supplements had significantly higher vitamin E intake levels and plasma α-tocopherol concentrations compared with consumers of other types of supplements, such as multivitamin and fish oil. Comparison with the Institute of Medicine Estimated Average Requirement of 12 mg/d indicated that when vitamin E intake from food and supplement sources was taken into account, 100 % of the study participants achieved the recommended intake levels. When vitamin E intake from food sources was taken into account, only 68·4 % of the females were found to achieve the recommended intake levels compared with 99·2 % of the males. The results of the present study show that dietary vitamin E intake has a significant effect on plasma α- and γ-tocopherol concentrations. Furthermore, they show that the consumption of supplements is a major contributor to overall intake and has a significant effect on plasma vitamin E concentrations in the Irish population.

  12. Effect of Carbohydrate Sources and Levels of Cotton Seed Meal in Concentrate on Feed Intake, Nutrient Digestibility, Rumen Fermentation and Microbial Protein Synthesis in Young Dairy Bulls

    Directory of Open Access Journals (Sweden)

    M. Wanapat

    2013-04-01

    Full Text Available The objective of this study was to investigate the effect of levels of cottonseed meal with various carbohydrate sources in concentrate on feed intake, nutrient digestibility, rumen fermentation and microbial protein synthesis in dairy bulls. Four, 6 months old dairy bulls were randomly assigned to receive four dietary treatments according to a 2×2 factorial arrangement in a 4×4 Latin square design. Factor A was carbohydrate source; cassava chip (CC and cassava chip+rice bran in the ratio of 3:1 (CR3:1, and factor B was cotton seed meal levels in the concentrate; 109 g CP/kg (LCM and 328 g CP/kg (HCM at similar overall CP levels (490 g CP/kg. Bulls received urea-lime treated rice straw ad libitum and were supplemented with 10 g of concentrate/kg BW. It was found that carbohydrate source and level of cotton seed meal did not have significant effects on ruminal pH, ammonia nitrogen concentration, microbial protein synthesis or feed intake. Animals which received CC showed significantly higher BUN concentration, ruminal propionic acid and butyric acid proportions, while dry matter, organic matter digestibility, populations of total viable bacteria and proteolytic bacteria were lower than those in the CR3:1 treatment. The concentration of total volatile fatty acids was higher in HCM than LCM treatments, while the concentration of butyric acid was higher in LCM than HCM treatments. The population of proteolytic bacteria with the LCM treatments was higher than the HCM treatments; however other bacteria groups were similar among the different levels of cotton seed meal. Bulls which received LCM had higher protein digestibility than those receiving HCM. Therefore, using high levels of cassava chip and cotton seed meal might positively impact on energy and nitrogen balance for the microbial population in the rumen of the young dairy bull.

  13. Absolute analysis of uranium isotopic concentrations with a gas ion source mass spectrometer; Analyses absolues des concentrations isotopiques de l'uranium par spectrometre de masse equipe d'une source a gaz

    Energy Technology Data Exchange (ETDEWEB)

    Chaussy, L.; Boyer, R. [Commissariat a l' Energie Atomique, Pierrelatte (France)

    1969-07-01

    Mass spectrometer with electronic bombardment ions source for routine uranium isotopic analysis are used like relative measurements apparatus. We show that such mass spectrometers can be used for absolute measurements with a very high sensitivity and precision which are ten times better than theses of thermo-ionic ions source mass spectrometer. We examine the causes of systematic errors and we give experimental data. In particular natural uranium sample used as reference give: U{sub 5} = 0.7202 {+-} 0.0005 atoms per cent; U{sub 4} = 0.00552 {+-} 0.0003 atoms per cent. The use of this method is justified for standards control. (authors) [French] Les spectrometres de masse a source par bombardement electronique pour l'analyse de l'uranium sous forme d'hexafluorure, sont utilises en routine comme des appareils de mesure relative. On montre que l'on peut utiliser de tels appareils pour effectuer des mesures absolues avec une excellente sensibilite et reproductibilite, dix fois superieure a celle des spectrometres a source thermoionique. On examine en detail les causes d'erreurs systematiques et on donne des resultats experimentaux. En particulier, l'analyse d'un echantillon d'uranium naturel donne: U{sub 5} = 0.7202 {+-} 0.0005 atomes pour cent; U{sub 4} = 0.00552 {+-} 0.0003 atomes pour cent. La technique de mesure est utile pour le controle d'etalons isotopiques. (auteurs)

  14. Concentrations and temporal variations of /sup 210/Po, /sup 210/Pb, and Al in the surf zone ecosystem of Copalis Beach, Washington

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, J T; Carpenter, R

    1979-01-01

    Surf diatoms monitored during a 21-month period at Copalis Beach, Washington, contained elevated concentrations of Al, /sup 210/Pb, and supported /sup 210/Po compared to net phytoplankton from Washington coastal waters and Puget Sound. Aluminum concentrations of several percent dry weight found in the surf diatoms were not a reflection of contamination by discrete inorganic particulate matter but were the result of a natural coating of clay-sized particles on Chaetoceros armatum, the predominant diatom in the surfblooms. A high correlation between Al and /sup 210/Pb in the surf diatoms suggests /sup 210/Pb and supported /sup 210/Po were also associated with the clay-sized particles. During fall through spring, the unsupported /sup 210/Po concentrations in the surf diatoms were correlated with the input of /sup 210/Po by precipitation. A summer maximum in unsupported /sup 210/Po concentrations in the surf diatoms may reflect upwelling that causes higher dissolved /sup 210/Po concentrations in the summer surf relative to those of late spring and early fall. The consumers of the surf diatoms exhibited larger /sup 210/Po-activity-to-/sup 210/Pb-activity ratios than their food, indicating /sup 210/Po was preferentially accumulated in the higher trophic level.

  15. The Effect of Source Suspended Sediment Concentration on the Sediment Dynamics of a Macrotidal Creek and Salt Marsh

    Science.gov (United States)

    Poirier, E.; van Proosdij, D.; Milligan, T. G.

    2017-12-01

    Seasonal variability in the sediment dynamics of a Bay of Fundy tidal creek and salt marsh system was analyzed to better understand the ecomorphodynamics of a high suspended sediment concentration intertidal habitat. Data were collected over 62 tides for velocity, suspended sediment concentration, deposition, and grain size at four stations from the creek thalweg to the marsh surface. Five topographic surveys were also conducted throughout the 14-month study. Deposition rates per tide varied spatially from 56.4 g·m-2 at the creek thalweg to 15.3 g·m-2 at the marsh surface. Seasonal variations in deposition in the creek and marsh surface were from 38.0 g·m-2 to 97.7 g·m-2 and from 12.2 g·m-2 to 19.6 g·m-2 respectively. Deposition and erosion were greatest in late fall and winter. This seasonal change, led by higher suspended sediment concentrations, was observed in the creek and at the marsh bank but notably absent from the marsh edge and marsh surface. Sediments were predominantly deposited in floc form (76-83%). Because of high floc content, higher suspended sediment concentrations led to more rapid loss of sediment from suspension. With increasing sediment concentration, deposition increased in the tidal creek and at the marsh bank but not at the marsh edge or marsh surface. This suggests that in highly flocculated environments the water column clears fast enough that very little sediment remains in suspension when the water reaches the marsh and that the sediment concentration during marsh inundation is independent of the initial concentration in the creek.

  16. Increasing fermentation efficiency at high sugar concentrations by supplementing an additional source of nitrogen during the exponential phase of the tequila fermentation process.

    Science.gov (United States)

    Arrizon, Javier; Gschaedler, Anne

    2002-11-01

    In the tequila industry, fermentation is traditionally achieved at sugar concentrations ranging from 50 to 100 g x L(-1). In this work, the behaviour of the Saccharomyces cerevisiae yeast (isolated from the juices of the Agave tequilana Weber blue variety) during the agave juice fermentation is compared at different sugar concentrations to determine if it is feasible for the industry to run fermentation at higher sugar concentrations. Fermentation efficiency is shown to be higher (above 90%) at a high concentration of initial sugar (170 g x L(-1)) when an additional source of nitrogen (a mixture of amino acids and ammonium sulphate, different than a grape must nitrogen composition) is added during the exponential growth phase.

  17. A One Year Study on the Concentrations of Norovirus and Enteric Adenoviruses in Wastewater and A Surface Drinking Water Source in Norway.

    Science.gov (United States)

    Grøndahl-Rosado, Ricardo C; Yarovitsyna, Ekaterina; Trettenes, Elin; Myrmel, Mette; Robertson, Lucy J

    2014-12-01

    Enteric viruses transmitted via the faecal-oral route occur in high concentrations in wastewater and may contaminate drinking water sources and cause disease. In order to quantify enteric adenovirus and norovirus genotypes I and II (GI and GII) impacting a drinking source in Norway, samples of surface water (52), wastewater inlet (64) and outlet (59) were collected between January 2011 and April 2012. Samples were concentrated in two steps, using an electropositive disc filter and polyethylene glycol precipitation, followed by nucleic acid extraction and analysis by quantitative polymerase chain reaction. Virus was detected in 47/52 (90.4%) of surface water, 59/64 (92%) of wastewater inlet and 55/59 (93%) of wastewater outlet samples. Norovirus GI occurred in the highest concentrations in surface water (2.51e + 04) and adenovirus in wastewater (2.15e + 07). While adenovirus was the most frequently detected in all matrices, norovirus GI was more frequently detected in surface water and norovirus GII in wastewater. This study is the first in Norway to monitor both sewage and a drinking water source in parallel, and confirms the year-round presence of norovirus and adenovirus in a Norwegian drinking water source.

  18. Near-source grid-based measurement of CO and PM2.5 concentration during a full-scale fire experiment in southern European shrubland

    Science.gov (United States)

    Amorim, J. H.; Valente, J.; Cascão, P.; Ribeiro, L. M.; Viegas, D. X.; Ottmar, R.; Miranda, A. I.

    2016-11-01

    There is limited research on the exposure of wildland firefighters to smoke because of the operational obstacles when monitoring air pollutants in the field. In this work, a grid of portable sensors was used to measure PM2.5 and CO concentrations in the near-source region during the burn of two shrubland research blocks in Central Portugal. Strong spatial variability of smoke levels was observed in the analysis of the ratios between mean concentrations of neighbouring sensors, with values as high as 4.4 for PM2.5 and 7.4 for CO. These large gradients were registered at a distance of only 5 m suggesting that considerable differences on individual exposure can occur depending on the location of that individual in relation to the smoke plume trajectory. Also, peak events of 2-3 times the mean were observed in periods exceeding 6 min. In the two experiments, the average concentrations of both PM2.5 and CO were higher during smouldering, which represents a risk of acute exposure due to the closer proximity of firefighters to the emission source during mop-up, stressing the importance of wearing portable gas detectors for managing critical exposure. The collected data constitutes a step forward in the effort to understand the mechanisms controlling the exposure during firefighting operations, by providing a source of information on near-ground concentration fluctuations within a biomass-burning smoke plume at a fine spatial-temporal resolution.

  19. Nature, source and composition of volcanic ash in sediments from a fracture zone trace of Rodriguez Triple Junction in the Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Mascarenhas-Pereira, M.B.L.; Nath, B.N.; Borole, D.V.; Gupta, S.M.

    Volcanic glasses associated with pumice, micro nodules and palagonite like lithic fragments were recovered from a volcanic terrain in a fracture zone defined as Rodriguez Triple Junction trace in the Central Indian Basin. Morphologically, the tephra...

  20. Resonance absorption measurements of atom concentrations in reacting gas mixtures. II. Calibration of microwave sources over a wide temperature range

    International Nuclear Information System (INIS)

    Chiang, C.; Lifshitz, A.; Skinner, G.B.; Wood, D.R.

    1979-01-01

    A series of experiments was carried out to calibrate three different microwave discharge lamps for analysis for D or H atoms, using Lyman-α absorption. Known concentrations of D atoms were produced in a shock tube by the reaction of 0.05--4 ppm D 2 with N 2 O in argon at 1800--3000 K. H atoms were produced by dissociation of 2,2,3,3-tetramethylbutane (10 ppm in argon) at 980--1140 K. These absorption data were compared with the absorption calculated from Lyman-α line shapes reported in an earlier paper, good agreement being found. These experiments provide a sound basis for obtaining the temperature and concentration dependence of the absorption coefficient over a wide temperature range, for H and D concentrations between 10 -12 and 10 -10 mole/cc

  1. Long-term particulate matter modeling for health effect studies in California - Part 2: Concentrations and sources of ultrafine organic aerosols

    Science.gov (United States)

    Hu, Jianlin; Jathar, Shantanu; Zhang, Hongliang; Ying, Qi; Chen, Shu-Hua; Cappa, Christopher D.; Kleeman, Michael J.

    2017-04-01

    Organic aerosol (OA) is a major constituent of ultrafine particulate matter (PM0. 1). Recent epidemiological studies have identified associations between PM0. 1 OA and premature mortality and low birth weight. In this study, the source-oriented UCD/CIT model was used to simulate the concentrations and sources of primary organic aerosols (POA) and secondary organic aerosols (SOA) in PM0. 1 in California for a 9-year (2000-2008) modeling period with 4 km horizontal resolution to provide more insights about PM0. 1 OA for health effect studies. As a related quality control, predicted monthly average concentrations of fine particulate matter (PM2. 5) total organic carbon at six major urban sites had mean fractional bias of -0.31 to 0.19 and mean fractional errors of 0.4 to 0.59. The predicted ratio of PM2. 5 SOA / OA was lower than estimates derived from chemical mass balance (CMB) calculations by a factor of 2-3, which suggests the potential effects of processes such as POA volatility, additional SOA formation mechanism, and missing sources. OA in PM0. 1, the focus size fraction of this study, is dominated by POA. Wood smoke is found to be the single biggest source of PM0. 1 OA in winter in California, while meat cooking, mobile emissions (gasoline and diesel engines), and other anthropogenic sources (mainly solvent usage and waste disposal) are the most important sources in summer. Biogenic emissions are predicted to be the largest PM0. 1 SOA source, followed by mobile sources and other anthropogenic sources, but these rankings are sensitive to the SOA model used in the calculation. Air pollution control programs aiming to reduce the PM0. 1 OA concentrations should consider controlling solvent usage, waste disposal, and mobile emissions in California, but these findings should be revisited after the latest science is incorporated into the SOA exposure calculations. The spatial distributions of SOA associated with different sources are not sensitive to the choice of

  2. Diurnal dynamics of the CO2 concentration in water of the coastal zone of lake Baikal in the ice period (testing of the DIEL - CO2 method for assessment of lake metabolic rate)

    Science.gov (United States)

    Panchenko, M. V.; Domysheva, V. M.; Pestunov, D. A.; Sakirko, M. V.; Ivanov, V. G.; Shamrin, A. M.

    2017-11-01

    Results of three long cycles of 24-hour measurements of the carbon dioxide content in the surface and bottom water in the ice period of 2014-2016 in the Baikal coastal zone are analyzed. The diurnal dynamics of the CO2 concentration in the subglacial water, in which photosynthesis plays the leading role, is described. It is found that, in comparison with the surface subglacial water (that is, directly adjacent to the ice bottom), the more pronounced diurnal rhythm of CO2 is observed in the bottom layer in all realizations. This rhythm is well correlated with pyranometer readings. The data on the diurnal dynamics of CO2 are used to estimate the gross primary production in the bottom water with the DIEL method based on the analysis of temporal variability of the carbon dioxide concentration in water in situ.

  3. Explicit control of image noise and error properties in cone-beam microtomography using dual concentric circular source loci

    International Nuclear Information System (INIS)

    Davis, Graham

    2005-01-01

    Cone-beam reconstruction from projections with a circular source locus (relative to the specimen) is commonly used in X-ray microtomography systems. Although this method does not provide an 'exact' reconstruction, since there is insufficient data in the projections, the approximation is considered adequate for many purposes. However, some specimens, with sharp changes in X-ray attenuation in the direction of the rotation axis, are particularly prone to cone-beam-related errors. These errors can be reduced by increasing the source-to-specimen distance, but at the expense of reduced signal-to-noise ratio or increased scanning time. An alternative method, based on heuristic arguments, is to scan the specimen with both short and long source-to-specimen distances and combine high frequency components from the former reconstruction with low frequency ones from the latter. This composite reconstruction has the low noise characteristics of the short source-to-specimen reconstruction and the low cone-beam errors of the long one. This has been tested with simulated data representing a particularly error prone specimen

  4. Source Material and Concentration of Wildfire-Produced Pyrogenic Carbon Influence Post-Fire Soil Nutrient Dynamics

    Directory of Open Access Journals (Sweden)

    Lucas A. Michelotti

    2015-04-01

    Full Text Available Pyrogenic carbon (PyC is produced by the thermal decomposition of organic matter in the absence of oxygen (O. PyC affects nutrient availability, may enhance post-fire nitrogen (N mineralization rates, and can be a significant carbon (C pool in fire-prone ecosystems. Our objectives were to characterize PyC produced by wildfires and examine the influence that contrasting types of PyC have on C and N mineralization rates. We determined C, N, O, and hydrogen (H concentrations and atomic ratios of charred bark (BK, charred pine cones (PC, and charred woody debris (WD using elemental analysis. We also incubated soil amended with BK, PC, and WD at two concentrations for 60 days to measure C and N mineralization rates. PC had greater H/C and O/C ratios than BK and WD, suggesting that PC may have a lesser aromatic component than BK and WD. C and N mineralization rates decreased with increasing PyC concentrations, and control samples produced more CO2 than soils amended with PyC. Soils with PC produced greater CO2 and had lower N mineralization rates than soils with BK or WD. These results demonstrate that PyC type and concentration have potential to impact nutrient dynamics and C flux to the atmosphere in post-fire forest soils.

  5. Metallurgical source-contribution analysis of PM10 annual average concentration: A dispersion modeling approach in moravian-silesian region

    Directory of Open Access Journals (Sweden)

    P. Jančík

    2013-10-01

    Full Text Available The goal of the article is to present analysis of metallurgical industry contribution to annual average PM10 concentrations in Moravian-Silesian based on means of the air pollution modelling in accord with the Czech reference methodology SYMOS´97.

  6. Sources of increase in lowermost stratospheric sulphurous and carbonaceous aerosol background concentrations during 1999–2008 derived from CARIBIC flights

    Directory of Open Access Journals (Sweden)

    Johan Friberg

    2014-03-01

    Full Text Available This study focuses on sulphurous and carbonaceous aerosol, the major constituents of particulate matter in the lowermost stratosphere (LMS, based on in situ measurements from 1999 to 2008. Aerosol particles in the size range of 0.08–2 µm were collected monthly during intercontinental flights with the CARIBIC passenger aircraft, presenting the first long-term study on carbonaceous aerosol in the LMS. Elemental concentrations were derived via subsequent laboratory-based ion beam analysis. The stoichiometry indicates that the sulphurous fraction is sulphate, while an O/C ratio of 0.2 indicates that the carbonaceous aerosol is organic. The concentration of the carbonaceous component corresponded on average to approximately 25% of that of the sulphurous, and could not be explained by forest fires or biomass burning, since the average mass ratio of Fe to K was 16 times higher than typical ratios in effluents from biomass burning. The data reveal increasing concentrations of particulate sulphur and carbon with a doubling of particulate sulphur from 1999 to 2008 in the northern hemisphere LMS. Periods of elevated concentrations of particulate sulphur in the LMS are linked to downward transport of aerosol from higher altitudes, using ozone as a tracer for stratospheric air. Tropical volcanic eruptions penetrating the tropical tropopause are identified as the likely cause of the particulate sulphur and carbon increase in the LMS, where entrainment of lower tropospheric air into volcanic jets and plumes could be the cause of the carbon increase.

  7. Black carbon concentrations and sources in the marine boundary layer of the tropical Atlantic Ocean using four methodologies

    Science.gov (United States)

    Combustion-derived aerosols in the marine boundary layer have been poorly studied, especially in remote environments such as the open Atlantic Ocean. The tropical Atlantic has the potential to contain a high concentration of aerosols, such as black carbon, due to the African emis...

  8. Subsurface occurrence and potential source areas of chlorinated ethenes identified using concentrations and concentration ratios, Air Force Plant 4 and Naval Air Station-Joint Reserve Base Carswell Field, Fort Worth, Texas

    Science.gov (United States)

    Garcia, C. Amanda

    2005-01-01

    The U.S. Geological Survey, in cooperation with the U.S. Air Force Aeronautical Systems Center, Environmental Management Directorate, conducted a study during 2003-05 to characterize the subsurface occurrence and identify potential source areas of the volatile organic compounds classified as chlorinated ethenes at U.S. Air Force Plant 4 (AFP4) and adjacent Naval Air Station-Joint Reserve Base Carswell Field (NAS-JRB) at Fort Worth, Texas. The solubilized chlorinated ethenes detected in the alluvial aquifer originated as either released solvents (tetrachloroethene [PCE], trichloroethene [TCE], and trans-1,2-dichloroethene [trans-DCE]) or degradation products of the released solvents (TCE, cis-1,2-dichloroethene [cis-DCE], and trans-DCE). The combined influences of topographic- and bedrock-surface configurations result in a water table that generally slopes away from a ground-water divide approximately coincident with bedrock highs and the 1-mile-long aircraft assembly building at AFP4. Highest TCE concentrations (10,000 to 920,000 micrograms per liter) occur near Building 181, west of Building 12, and at landfill 3. Highest PCE concentrations (500 to 920 micrograms per liter) occur near Buildings 4 and 5. Highest cis-DCE concentrations (5,000 to 710,000 micrograms per liter) occur at landfill 3. Highest trans-DCE concentrations (1,000 to 1,700 micrograms per liter) occur just south of Building 181 and at landfill 3. Ratios of parent-compound to daughter-product concentrations that increase in relatively short distances (tens to 100s of feet) along downgradient ground-water flow paths can indicate a contributing source in the vicinity of the increase. Largest increases in ratio of PCE to TCE concentrations are three orders of magnitude from 0.01 to 2.7 and 7.1 between nearby wells in the northeastern part of NAS-JRB. In the northern part of NAS-JRB, the largest increases in TCE to total DCE concentration ratios relative to ratios at upgradient wells are from 17 to

  9. Associations between plasma concentrations of PCB 28 and possible indoor exposure sources in Danish school children and mothers.

    Science.gov (United States)

    Egsmose, Emilie Lund; Bräuner, Elvira Vaclavik; Frederiksen, Marie; Mørck, Thit Aarøe; Siersma, Volkert Dirk; Hansen, Pernille Winton; Nielsen, Flemming; Grandjean, Philippe; Knudsen, Lisbeth E

    2016-02-01

    Polychlorinated biphenyls (PCBs) are ubiquitously present in the environment and are suspected of carcinogenic, neurotoxic and immunotoxic effects. Significantly higher plasma concentrations of the congener PCB 28 occur in children compared to adults. Exposure in schools may contribute to this difference. To determine whether increased blood plasma concentrations of PCB 28 in Danish school children and mothers are associated with living in homes or attending schools constructed in the PCB period (1959-1977). PCB 28 was analyzed in plasma samples from 116 children aged 6-11years and 143 mothers living in an urban and a rural area in Denmark and partici