Science.gov

Sample records for air toxics removal

  1. Comparing toxic air pollutant programs

    SciTech Connect

    Hawkins, S.C.

    1997-05-01

    This article compares state and federal toxic air pollutant programs. The Clean Air Act Ammendments created a program for the control of Hazardous Air Pollutants based on the establishment of control technology standards. State toxic programs can be classified into two categories: control technology-based and ambient concentration-based. Many states have opened to implement the MACT standards while enforcing their own state air toxics programs. Specific topics discussed include the following: the Federal air toxics program; existing state regulations; New Jersey Air Toxic Program; New York Toxics program.

  2. Baltimore Air Toxics Study (BATS)

    SciTech Connect

    Sullivan, D.A.

    1996-12-31

    The Baltimore Air Toxics Study is one of the three urban air toxics initiatives funded by EPA to support the development of the national air toxics strategy. As part of this project, the Air Quality Integrated Management System (AIMS) is under development. AIMS is designed to bring together the key components of urban air quality management into an integrated system, including emissions assessment, air quality modeling, and air quality monitoring. Urban area source emissions are computed for a wide range of pollutants and source categories, and are joined with existing point source emissions data. Measured air quality data are used to evaluate the adequacy of the emissions data and model treatments as a function of season, meteorological parameters, and daytime/nighttime conditions. Based on tested model performance, AIMS provides the potential to improve the ability to predict air quality benefits of alternative control options for criteria and toxic air pollutants. This paper describes the methods used to develop AIMS, and provides examples from its application in the Baltimore metropolitan area. The use of AIMS in the future to enhance environmental management of major industrial facilities also will be addressed in the paper.

  3. Conceptual Approach For Estimating Potential Air Toxics And Radionuclide Airborne Emissions From A Temporary Exhaust System For The 216-Z-9 Crib Removal Action

    SciTech Connect

    Hopkins, A.; Sutter, C.; O'Brien, P.; Bates, J.; Klos, B.; Teal, J.; Oates, L.

    2008-07-01

    The 216-Z-9 Crib, located at the Hanford Nuclear Reservation in southeastern Washington State, was the site of a successful mining effort to recover plutonium from the contaminated soils at the disposal site. A CERCLA Action Memorandum (AM) issued by the U.S. Department of Energy (DOE) requires the removal of the buildings associated with this mining effort to facilitate a remedial action planned for the near future. The decontamination and demolition of the 216 Z-9 Crib facilities is required under a consent order between the DOE, the U.S Environmental Protection Agency (EPA) and the Washington State Department of Ecology (Ecology). Removal of the buildings located on and near the concrete cover slab over the 216-Z-9 Crib will require removal of the large soil-packaging glovebox located inside the 216-Z- 9A Building. Prior to cleaning out the glovebox, it will be necessary to provide active filtered ventilation capability to ensure a negative pressure exists between the glovebox and the adjacent airspace while hands-on work proceeds within. The glovebox floor is open to the Z-9 crib cavern environment below. For this reason the crib and glovebox currently share a common airspace. The functional requirements for safely conducting work within the glovebox include provision of a negative pressure in the box of about 0.5 inches of water gage (nominal) less than the interior of the building. In addition, the building surrounding the glovebox will be maintained at a slight negative pressure with respect to outdoor ambient pressure. In order to assess the relevant and appropriate clean air requirements for the new temporary ventilation system and associated emissions monitoring, it was necessary to reliably predict the nature of the exhaust air stream. Factors used to predict the presence and concentrations of certain radionuclide particulates and certain gases considered to be air toxics, included reliability parameters, flow rates, radionuclide content, and off

  4. Criteria air pollutants and toxic air pollutants.

    PubMed Central

    Suh, H H; Bahadori, T; Vallarino, J; Spengler, J D

    2000-01-01

    This review presents a brief overview of the health effects and exposures of two criteria pollutants--ozone and particulate matter--and two toxic air pollutants--benzene and formaldehyde. These pollutants were selected from the six criteria pollutants and from the 189 toxic air pollutants on the basis of their prevalence in the United States, their physicochemical behavior, and the magnitude of their potential health threat. The health effects data included in this review primarily include results from epidemiologic studies; however, some findings from animal studies are also discussed when no other information is available. Health effects findings for each pollutant are related in this review to corresponding information about outdoor, indoor, and personal exposures and pollutant sources. Images Figure 3 Figure 8 Figure 9 PMID:10940240

  5. Controlling air toxics through advanced coal preparation

    SciTech Connect

    Straszheim, W.E.; Buttermore, W.H.; Pollard, J.L.

    1995-11-01

    This project involves the assessment of advanced coal preparation methods for removing trace elements from coal to reduce the potential for air toxic emissions upon combustion. Scanning electron microscopy-based automated image analysis (SEM-AIA) and advanced washability analyses are being applied with state-of-the-art analytical procedures to predict the removal of elements of concern by advanced column flotation and to confirm the effectiveness of preparation on the quality of quantity of clean coal produced. Specific objectives are to maintain an acceptable recovery of combustible product, while improving the rejection of mineral-associated trace elements. Current work has focused on determining conditions for controlling column flotation system across its operating range and on selection and analysis of samples for determining trace element cleanability.

  6. COMMUNITY SCALE AIR TOXICS MODELING WITH CMAQ

    EPA Science Inventory

    Consideration and movement for an urban air toxics control strategy is toward a community, exposure and risk-based modeling approach, with emphasis on assessments of areas that experience high air toxic concentration levels, the so-called "hot spots". This strategy will requir...

  7. Development of spacecraft toxic gas removal agents

    NASA Technical Reports Server (NTRS)

    Moore, R. S.

    1974-01-01

    The development of agents suitable for removal of CO, NH3, NO2 SO2, and other spacecraft contaminants was approached. An extensive technology review was conducted, yielding a large number of potentially useful materials and/or concepts. Because the two toxic gases of greatest interest, CO and NH3, suggested the use of catalysis principles emphasis was placed on the intestigation of transition metals on various supports. Forty-three materials were prepared or obtained and 25 were tested. Gas chromatographic techniques were used to find seven candidates that effectively managed various combinations of the four toxic gases: none managed all. These candidates included six transition metal-containing preparations and a supported LiOH material. Three commercial charcoals showed some efficiency for the toxic gases and may constitute candidates for enhancement by doping with transition metals.

  8. PRECOMBUSTION REMOVAL OF HAZARDOUS AIR POLLUTANT PRECURSORS

    SciTech Connect

    Unknown

    2000-10-09

    In response to growing environmental concerns reflected in the 1990 Clean Air Act Amendment (CAAA), the United States Department of Energy (DOE) sponsored several research and development projects in late 1995 as part of an initiative entitled Advanced Environmental Control Technologies for Coal-Based Power Systems. The program provided cost-shared support for research and development projects that could accelerate the commercialization of affordable, high-efficiency, low-emission, coal-fueled electric generating technologies. Clean coal technologies developed under this program would serve as prototypes for later generations of technologies to be implemented in the industrial sector. In order to identify technologies with the greatest potential for commercial implementation, projects funded under Phase I of this program were subject to competitive review by DOE before being considered for continuation funding under Phase II. One of the primary topical areas identified under the DOE initiative relates to the development of improved technologies for reducing the emissions of air toxics. Previous studies have suggested that many of the potentially hazardous air pollutant precursors (HAPPs) occur as trace elements in the mineral matter of run-of-mine coals. As a result, these elements have the potential to be removed prior to combustion at the mine site by physical coal cleaning processes (i.e., coal preparation). Unfortunately, existing coal preparation plants are generally limited in their ability to remove HAPPs due to incomplete liberation of the mineral matter and high organic associations of some trace elements. In addition, existing physical coal cleaning plants are not specifically designed or optimized to ensure that high trace element rejections may be achieved.

  9. SNRB{trademark} air toxics monitoring. Final report

    SciTech Connect

    Not Available

    1994-01-01

    Babcock & Wilcox (B&W) is currently conducting a project under the DOE`s Clean Coal Technology (CCT II) Program to demonstrate its SO{sub x}NO{sub x}-Rox Box{trademark} (SNRB{trademark}) process in a 5 MWe Field Demonstration Unit at Ohio Edison`s R. E. Burger Plant near Shadyside, Ohio. The objective of the SNRB{trademark} Air Toxics Monitoring Project was to provide data on SNRB{trademark} air toxics emissions control performance to B&W and to add to the DOE/EPRI/EPA data base by quantifying the flow rates of selected hazardous substances (or air toxics) in all of the major input and output streams of the SNRB{trademark} process as well as the power plant. Work under the project included the collection and analysis of representative samples of all major input and output streams of the SNRB{trademark} demonstration unit and the power plant, and the subsequent laboratory analysis of these samples to determine the partitioning of the hazardous substances between the various process streams. Material balances for selected air toxics were subsequently calculated around the SNRB{trademark} and host boiler systems, including the removal efficiencies across each of the major air pollution control devices. This report presents results of the SNRB{trademark} Air Toxics Monitoring Project. In addition to the Introduction, a brief description of the test site, including the Boiler No. 8 and the SNRB{trademark} process, is included in Section H. The concentrations of air toxic emissions are presented in Section II according to compound class. Material balances are included in Section IV for three major systems: boiler, electrostatic precipitator, and SNRB{trademark}. Emission factors and removal efficiencies are also presented according to compound class in Sections V and VI, respectively. A data evaluation is provided in Section VII.

  10. Compositions and methods for removal of toxic metals and radionuclides

    NASA Technical Reports Server (NTRS)

    Cuero, Raul G. (Inventor); McKay, David S. (Inventor)

    2007-01-01

    The present invention relates to compositions and methods for the removal of toxic metals or radionuclides from source materials. Toxic metals may be removed from source materials using a clay, such as attapulgite or highly cationic bentonite, and chitin or chitosan. Toxic metals may also be removed using volcanic ash alone or in combination with chitin or chitosan. Radionuclides may be removed using volcanic ash alone or in combination with chitin or chitosan.

  11. AIR TOXICS MODELING RESEARCH PROGRAM: AN OVERVIEW

    EPA Science Inventory

    This product is a Microsoft Powerpoint slide presentation which was given at the joint EPA Region 3 - Mid-Atlantic Regional Air Management Association (MARAMA) Air Toxic Summit in Philadelphia, Pennsylvania held from October 18, 2005 through October 20, 2005. The slide presentat...

  12. Implementing Title III -- Air toxics

    SciTech Connect

    Shaw, B.W.

    1995-12-31

    The South Coast Air Quality Management District (AQMD) is taking three basic approaches to implementing the new National Emissions Standards for Hazardous Air Pollutants (NESHAPs) from the Title III program: accept and implement, as written, the NESHAPs where few sources are located in the South Coast Air Basin; incorporate with simplification of the NESHAP requirements into AQMD rules when many sources are involved; then seek equivalency by the US EPA; and incorporate with a market-based rule (VOC RECLAIM), part of many NESHAPs which control volatile organic compound as HAPs. Whatever the approach, emphasis will be placed on: streamlining and simplification; helping sources understand requirements and comply; and common sense.

  13. Air toxics: sources and monitoring in Texas.

    PubMed Central

    Pendleton, D R

    1995-01-01

    Since the late 1980s, federal legislation has required industries to publicly report their annual emissions of toxic compounds. Industry reports show the largest contributor to toxic emission levels in Texas is the massive concentration of petrochemical industries along the Gulf Coast. It is interesting to note that although Texas produces over 50% of the nation's synthetic chemicals, it discharges less than 8% of the nation's toxic emissions. However, in response to growing concerns about the effects of these toxic emissions, the Texas Natural Resource Conservation Commission (TNRCC) initiated a long-term program for monitoring toxic chemicals in the air. This article provides details of this monitoring program as well as industry-funded toxic monitoring networks in Texas. This includes information on the technology currently being used for sample collection and analysis as well as plans for implementing methods that are on the technological horizon. Finally, details of some key measurements from the state's air toxics monitoring network will be provided along with an explanation of how they impact current air quality trends in Texas. PMID:8549477

  14. Measurement of toxic and related air pollutants

    SciTech Connect

    Jayanty, R.K.M.; Gay, B.W. Jr.

    1990-12-01

    A joint conference for the fifth straight year cosponsored by the Air and Waste Management Association's EM-3, EM-4, and ITF-2 technical committees, and the Atmospheric Research and Exposure Assessment Laboratory (AREAL) of the US Environmental Protection Agency, was held in Raleigh, North Carolina, May 1-4, 1990. The technical program consisted of 187 presentations, held in 20 technical sessions, on recent advances in the measurement and monitoring of toxic and related pollutants found in ambient and source atmospheres. Covering a wide range of measurement topics and supported by 66 exhibitors of instrumentation and consulting services, the symposium was attended by more than 850 professionals from the US and other countries. This overview highlights a selection of the technical presentations. A synopsis of the keynote address to the symposium is also included. Presentations include: (1) radon, (2) atmospheric chemistry and fate of toxic pollutants, (3) supercritical fluid extraction, (4) acidic deposition, (5) determination of polar and volatile organic pollutants in ambient air, (6) Delaware Superfund innovative technology evaluation (SITE) study, (7) mobile sources emissions characterization, (8) Superfund site air monitoring, (9) exposure assessment, (10) chemometrics and environmental data analysis, (11) nicotine in environmental tobacco smoke, (12) source monitoring, (13) effects of air toxics on plants, (14) measurement of volatile organic pollutants, (15) general, (16) air pollution dispersion modeling, (17) measurement of hazardous waste emissions, (18) measurement of indoor toxic air contaminants, and (19) environmental quality assurance.

  15. Toxic effects of air freshener emissions.

    PubMed

    Anderson, R C; Anderson, J H

    1997-01-01

    To evaluate whether emissions of a commercial air freshener produced acute toxic effects in a mammalian species, the authors allowed male Swiss-Webster mice to breathe the emissions of one commercial-brand solid air freshener for 1 h. Sensory irritation and pulmonary irritation were evaluated with the ASTM-E-981 test. A computerized version of this test measured the duration of the break at the end of inspiration and the duration of the pause at the end of expiration--two parameters subject to alteration via respiratory effects of airborne toxins. Measurements of expiratory flow velocity indicated changes in airflow limitation. The authors then subjected mice to a functional observational battery, the purpose of which was to probe for changes in nervous system function. Emissions of this air freshener at several concentrations (including concentrations to which many individuals are actually exposed) caused increases in sensory and pulmonary irritation, decreases in airflow velocity, and abnormalities of behavior measured by the functional observational battery score. The test atmosphere was subjected to gas chromatography/mass spectroscopy, and the authors noted the presence of chemicals with known irritant and neurotoxic properties. The Material Safety Data Sheet for the air freshener indicated that there was a potential for toxic effects in humans. The air freshener used in the study did not diminish the effect of other pollutants tested in combination. The results demonstrated that the air freshener may have actually exacerbated indoor air pollution via addition of toxic chemicals to the atmosphere.

  16. Environmental air toxics: role in asthma occurrence?

    PubMed

    Larsen, Gary L; Beskid, Craig; Shirnamé-Moré, Lata

    2002-08-01

    The National Urban Air Toxics Research Center (NUATRC) hosted its first scientific workshop in 1994 that focused on possible relationships between air toxics and asthma. From that meeting came recommendations for future research including a need for more complete individual personal exposure assessments so that determinations of personal exposures to pollutants could be made. In the spring of 2001, NUATRC held a second such workshop to review progress made in this area during the intervening 7 years. Peer-reviewed articles from the workshop are published in this issue of (italic)Environmental Health Perspectives Supplements(/italic). As in 1994, academic, government, and industry scientists participated. Dave Guinnup of the Environmental Protection Agency discussed the nature of air toxics, their definition, and the basis for federal regulation. George Leikauf from the University of Cincinnati reviewed the 1994 workshop and subsequent research in this field. Current research funded by NUATRC that is addressing individual personal exposure was presented by Clifford Weisel (Environmental and Occupational Health Sciences Institute, University of Medicine and Dentistry of New Jersey), Patrick Kinney (Columbia University) and Candis Claiborn (Washington State University). David Corry from Baylor College of Medicine highlighted new insights into asthma pathogenesis while Stephen Redd from the Centers for Disease Control presented an overview of asthma epidemiology as well as the societal costs of the disease. Mary White (Agency for Toxic Substances and Disease Registry) discussed recent epidemiologic investigations by public health agencies into community concerns about asthma and hazardous air pollutants. David Peden (University of North Carolina) reviewed scientific studies into the links between asthma and air toxics as well as criteria air pollutants. In a session on occupational asthma, Lee Petsonk (National Institute for Occupational Safety and Health) discussed

  17. Air toxics regulatory issues facing urban settings.

    PubMed Central

    Olden, K; Guthrie, J

    1996-01-01

    Biomarker research does not exist in isolation. Its usefulness can only be realized when it is translated into prevention strategies to protect public health. In the context of air toxics, these prevention strategies begin with the development of regulatory standards derived from risk assessment schemes. The Clean Air Act Amendments of 1990 list 189 air toxics, including many volatile organics, metals, and pesticides. The National Institute of Environmental Health Sciences (NIEHS), through its affiliation with the National Toxicology Program, has generated toxicity and carcinogenicity data on more than 100 of these air toxics. The NIEHS extramural and intramural research portfolios support a variety of projects that develop and validate biomarkers for use in environmental health science and risk assessment. Biomarkers have a tremendous potential in the areas of regulating air toxics and protecting public health. Risk assessors need data provided by biomarkers of exposure, biomarkers of dose/pharmacokinetics, biomarkers of susceptibility or individual variability, and biomarkers of effects. The greatest benefit would be realized if biomarkers could be employed in four areas of primary and secondary prevention. The first is the use of biomarkers to enhance extrapolation of animal data to human exposure situations in establishing risk standards. The second is the use of biomarkers that assess noncancer, as well as cancer, end points. Important health end points include pulmonary dysfunction, immunotoxicity, and neurotoxicity. Third, biomarkers that serve as early waming signs to detect intermediate effects would enhance our ability to design timely and cost-effective intervention strategies. Finally, biomarkers used to evaluate the effectiveness of intervention strategies, both in clinical and regulatory settings, would enable us to ensure that programs designed to protect public health do, in fact, achieve the desired outcome. PMID:8933026

  18. NATIONAL-SCALE ASSESSMENT OF AIR TOXICS RISKS

    EPA Science Inventory

    The national-scale assessment of air toxics risks is a modeling assessment which combines emission inventory development, atmospheric fate and transport modeling, exposure modeling, and risk assessment to characterize the risk associated with inhaling air toxics from outdoor sour...

  19. Groundwater air stripping: Effect on water toxicity

    SciTech Connect

    Eldridge, R.B.; Simpson, C.W.; Elliott, D.J.

    1995-02-01

    An air stripping unit was designed to reduce groundwater hydrocarbon content and biotoxicity to acceptable levels. A pilot plant study was conducted to determine the water treatability and to optimize the commercial unit design conditions. A measurement of the pilot plant effluent toxicity was obtained from {open_quotes}Microtox{close_quotes} analysis and rigorous bio-assays. These results indicated that reduction of the water hydrocarbon content to permitted discharge limits was accompanied by the elimination of water toxicity. The Onda mass transfer model was used to prepare the commercial unit design. A post-installation evaluation indicated that the model gave a good representation of the commercial unit performance. Toxicity reductions observed in the pilot plant were also observed in the commercial unit. 3 refs., 5 figs., 3 tabs.

  20. Evaporation and air-stripping to assess and reduce ethanolamines toxicity in oily wastewater.

    PubMed

    Libralato, G; Ghirardini, A Volpi; Avezzù, F

    2008-05-30

    Toxicity from industrial oily wastewater remains a problem even after conventional activated sludge treatment process, because of the persistence of some toxicant compounds. This work verified the removal efficiency of organic and inorganic pollutants and the effects of evaporation and air-stripping techniques on oily wastewater toxicity reduction. In a lab-scale plant, a vacuum evaporation procedure at three different temperatures and an air-stripping stage were tested on oily wastewater. Toxicity reduction/removal was observed at each treatment step via Microtox bioassay. A case study monitoring real scale evaporation was also done in a full-size wastewater treatment plant (WWTP). To implement part of a general project of toxicity reduction evaluation, additional investigations took into account the monoethanolamine (MEA), diethanolamine (DEA) and triethanolamine (TEA) role in toxicity definition after the evaporation phase, both as pure substances and mixtures. Only MEA and TEA appeared to contribute towards effluent toxicity.

  1. Chemical air pollutants and otorhinolaryngeal toxicity

    SciTech Connect

    Bisesi, M.S.; Rubin, A.M. . Occupational Health and Otolaryngology)

    1994-03-01

    Air pollution and the specific issue regarding the impact of airborne chemical agents to human health are familiar topics to most members of the environmental health science and environmental medicine communities. Some aspects, however, have received relatively less attention. Much has been published regarding the impact of air pollutants on the human upper and lower respiratory system, including interaction with the rhinologic (nasal) system. Relatively fewer data have been published, however, regarding the potential impact of air pollutants in reference specifically to the otologic (auditory and vestibular) and the laryngeal (larynx) system. Adverse impact to the ears, nose and throat, referred to as the otorhinolaryngeal system'', warrants attention as an important environmental health issue. Toxic interactions from exposure to many chemical air pollutants not only causes potential respiratory irritation and lung disease, but can also result in impaired hearing, balance, sense of smell, taste, and speech due to interaction with related target systems. This may be significant to environmental health risk assessment of chemical air pollutants if multi-target site models are considered.

  2. Comparison of different physico-chemical methods for the removal of toxicants from landfill leachate.

    PubMed

    Cotman, Magda; Gotvajn, Andreja Zgajnar

    2010-06-15

    Our work was focused on investigation of different treatment procedures for the removal of toxic fractions from a landfill leachate, because sometimes the existing treatment in biological sequencing batch reactor (SBR) is not efficient enough, leading to a hazardous environmental impact of the present persistent and toxic compounds. The efficiency of the procedures used was monitored by chemical analyses and two toxicity tests (activated sludge and Vibrio fischeri). The existing SBR (HRT=1.9 days) removed 46-78% of COD and 96-73% of NH(4)(+)-N. Experiments were conducted with three landfill leachate samples expressing significant difference in concentrations of pollutants and with low BOD(5)/COD ratio (0.06/0.01/0.03). The applied methods were air stripping, adsorption to activated carbon and zeolite clinoptilolite and Fenton oxidation. Air stripping at pH 11 was a viable treatment option for the removal of ammonia nitrogen (up to 94%) and reduction of toxicity to microorganisms. In the adsorption experiments in batch system with different concentration of PAC the most effective was the highest addition (50.0gL(-1)) where 63-92% of COD was removed followed by significant reduction in toxicity to V. fischeri. In the column experiments with clinoptilolite 45/93/100% of NH(4)(+)-N as well as 25/32/39% of COD removal was attained. The removal efficiency for metals followed the sequence Cr>Zn>Cd>Ni. The procedure with zeolite was the second most efficient one regarding reduction of toxicity to both organisms. Fenton oxidation at molar ratio Fe(2+):H(2)O(2)=1.0:10.0 assured 70-85% removal of COD but it only slightly reduced the toxicity.

  3. The Air Toxics Health Effects Database (ATHED)

    SciTech Connect

    Woodall, George M. Smith, Roy L.

    2008-11-15

    The Air Toxics Health Effects Database (ATHED) is currently used by the EPA's Office of Air Quality Planning and Standards (OAQPS) to support risk assessments for the Residual Risk Program. An assessment of the residual risk is required to be performed at a specified time (typically 8years) following the promulgation of a technology-based Maximum Achievable Control Technologies (MACT) standard. The goal of the Residual Risk Program is to assure that the risk that remains after MACT standards are implemented (i.e., the 'residual risk') is acceptable, and if not, to propose additional regulations to mitigate those risks. ATHED maintains all available reference values for each chemical as separate data records, and includes values for all exposure durations (acute, short-term, subchronic and chronic). These values are used as benchmarks to determine acceptable exposure levels to the hazardous air pollutants (HAPs) listed in Section 112 of the Clean Air Act. ATHED also provides useful background information on the uncertainty and/or modifying factors that were applied in the derivation of each reference value, as well as the point of departure and the critical study/studies. To facilitate comparisons across durations for a specific chemical, ATHED data can be graphically presented.

  4. Toluene removal from air by Dieffenbachia in a closed environment

    NASA Astrophysics Data System (ADS)

    Porter, J. R.

    1994-11-01

    Higher plants are likely to play a major role in bioregeneration systems for food, air and water supplies. Plants may also contribute by the removal of toxic organic substances from the air of a closed environment. Dieffenbachia amoena plants were exposed to 0 to 1.2 × 106 μg toluene.m-3 at light intensities of 35 and 90 μmol.m-2.s-1 in sealed chambers. Toluene removal, photosynthesis and respiration were measured. An increased light inten-sity increased the rate of toluene removal five-fold over the rate at the lower intensity; the kinetics suggest active regulation by the plant. The removal rate saturated at 2700 μg toluene.h-1 at the lower intensity and failed to saturate at the higher intensity. Toluene exposure inhibited photosynthesis and respiration only transiently and without correlation to toluene concentration. These plants can act as efficient scavengers of toluene in a contaminated environment. 1990 and 1991 NASA/ASEE Summer Faculty Research Fellow, National Science and Technology Laboratory, John C. Stennis Space Center, Stennis Space Center, MS 39529

  5. An assessment of air toxics in Minnesota.

    PubMed

    Pratt, G C; Palmer, K; Wu, C Y; Oliaei, F; Hollerbach, C; Fenske, M J

    2000-09-01

    We used monitoring and modeling to assess the concentrations of air toxics in the state of Minnesota. Model-predicted concentrations for 148 hazardous air pollutants were from the U.S. Environmental Protection Agency Cumulative Exposure Project (1990 data). Monitoring data consisted of samples of volatile organic compounds, carbonyls, and particulate matter [Less than and equal to] 10 microm in aerodynamic diameter collected at 25 sites throughout the state for varying periods of time (up to 8 years; 1991-1998). Ten pollutants exceeded health benchmark values at one or more sites by modeling, monitoring, or both (including acrolein, arsenic, benzene, 1,3-butadiene, carbon tetrachloride, chromium, chloroform, ethylene dibromide, formaldehyde, and nickel). Polycyclic organic matter also exceeded the benzo[a]pyrene health benchmark value assumed to represent this class of pollutants. The highest modeled and monitored concentrations of most pollutants were near the center of the Minneapolis-St. Paul metropolitan area; however, many smaller cities throughout the state also had elevated concentrations. Where direct comparisons were possible, monitored values often tended to exceed model estimates. Upper-bound excess lifetime inhalation cancer risks were estimated to range from 2.7 [times] 10(-5) to 140. 9 [times] 10(-5) (modeling) and 4.7 [times] 10(-5) to 11.0 [times] 10(-5) (using a smaller set of monitored carcinogens). Screening noncancer hazard indices summed over all end points ranged from 0.2 to 58.1 (modeling) and 0.6 to 2.0 (with a smaller set of monitored pollutants). For common sets of pollutants, the concentrations, cancer risks, and noncancer hazard indices were comparable between model-based estimates and monitored values. The inhalation cancer risk was apportioned to mobile sources (54%), area sources (22%), point sources (12%), and background (12%). This study provides evidence that air toxics are a public health concern in Minnesota.

  6. Emissions of air toxics from coal-fired boilers: Arsenic

    SciTech Connect

    Mendelsohn, M.H.; Huang, H.S.; Livengood, C.D.

    1994-08-01

    Concerns over emissions of hazardous air pollutants (air toxics) have emerged as a major environmental issue; the authority of the US Environmental Protection Agency to regulate such pollutants has been greatly expanded through passage of the Clean Air Act Amendments of 1990. Arsenic and arsenic compounds are of concern mainly because of their generally recognized toxicity. Arsenic is also regarded as one of the trace elements in coal subject to significant vaporization. This report summarizes and evaluates available published information on the arsenic content of coals mined in the United States, on arsenic emitted in coal combustion, and on the efficacy of various environmental control technologies for controlling airborne emissions. Bituminous and lignite coals have the highest mean arsenic concentrations, with subbituminous and anthracite coals having the lowest. However, all coal types show very significant variations in arsenic concentrations. Arsenic emissions from coal combustion are not well-characterized, particularly with regard to determination of specific arsenic compounds. Variations in emission, rates of more than an order of magnitude have been reported for some boiler types. Data on the capture of arsenic by environmental control technologies are available primarily for systems with cold electrostatic precipitators, where removals of approximately 50 to 98% have been reported. Limited data for wet flue-gas-desulfurization systems show widely varying removals of from 6 to 97%. On the other hand, waste incineration plants report removals in a narrow range of from 95 to 99%. This report briefly reviews several areas of research that may lead to improvements in arsenic control for existing flue-gas-cleanup technologies and summarizes the status of analytical techniques for measuring arsenic emissions from combustion sources.

  7. Fuel tank air pocket removal device

    SciTech Connect

    Wilson, C.N. II.

    1991-10-08

    This paper describes a device for the removal of air pockets from filled underground fuel storage tanks. It comprises: a hollow rigid guide column of sufficient length to extend through a fuel inlet opening of the storage tank to the bottom thereof; a rotatable assembly affixed to the lower end of the column and containing guide means for facilitating the passage of a hose from the guide column to the most distant point of the walls of the storage tank; a hose slidably mounted within and extendable from and retractable into the guide column and having means for maintaining the air hose in a plane essentially parallel to the bottom of the storage tank; a first end of a tubular means connected to a first end of the hose, the tubular means comprising flotation means, the flotation means causing a second end of the tubular means to contact the air pocket; and means on a second end of the hose for extending and retracting the hose through the guide column so as to reach any point within the storage tank.

  8. EMISSIONS OF ORGANIC AIR TOXICS FROM OPEN BURNING

    EPA Science Inventory

    A detailed literature search was performed to collect and collate available data reporting emissions of toxic organic substances into the air from open burning sources. Availability of data varied according to the source and the class of air toxics of interest. Volatile organic c...

  9. Multiple Air-Toxics Exposure Study Working Paper Number 3. Urban air-toxics exposure model: development and application

    SciTech Connect

    Not Available

    1988-11-01

    The South Coast Air Quality Management District of California completed a Multiple Air Toxics Exposure Study (MATES) that examines the additive risk from a number of air toxics on an urban area. The project, though partially funded by EPA, is an example of how a State or local agency may approach assessing their local air-toxics risks as is encouraged by EPA's Urban Air Toxics Program which results from EPA's Air Toxic Strategy. The report is a summary of the methods used by the California agency. Though not intended as an endorsement of the entire contents of the report, EPA is reproducing their report (Working Paper Number 3) to benefit and encourage other agencies that may be contemplating such an assessment.

  10. Assessing exposure to air toxics relative to asthma.

    PubMed Central

    Weisel, Clifford P

    2002-01-01

    Asthma is a respiratory disease whose prevalence has been increasing since the mid 1970s and that affects more than 14.6 million residents of the United States. Environmental triggers of asthma include air pollutants that are respiratory irritants. Air toxics emitted into the ambient air are listed in the 1990 Clean Air Act Amendments as hazardous air pollutants (HAPs) if they can adversely affect human health, including the respiratory tract. HAPs include particulate and gaseous-phase pollutants, individual organic compounds and metals, and mixtures. Associations between asthma exacerbation and both particles and indoor volatile organic compounds (VOCs), often referred to as indoor air quality, have been reported. Studies conducted in the United States, Canada, and Europe over the past two decades have shown that most people living in the developed countries spend the majority of their time indoors and that the air concentrations of many air toxics or HAPs are higher indoors than in the ambient air in urban, suburban, and rural settings. Elevated indoor air concentrations result from emissions of air toxics from consumer products, household furnishings, and personal activities. The Relationship of Indoor, Outdoor and Personal Air (RIOPA) study was designed to oversample homes in close proximity to ambient sources, excluding residences where smokers lived, to determine the contribution of ambient emissions to air toxics exposure. The ratios of indoor to outdoor air concentrations of some VOCs in homes measured during RIOPA were much greater than one, and for most other VOCs that had indoor-to-outdoor ratios close to unity in the majority of homes, elevated ratios were found in the paired samples with the highest concentration. Thus, although ambient emissions contribute to exposure of some air toxics indoors as well as outdoors, this was not true for all of the air toxics and especially for the higher end of exposures to most volatile organic air toxics examined

  11. Odor and volatile organic compound removal from wastewater treatment plant headworks ventilation air using a biofilter.

    PubMed

    Converse, B M; Schroeder, E D; Iranpour, R; Cox, H H J; Deshusses, M A

    2003-01-01

    Laboratory-scale experiments and field studies were performed to evaluate the feasibility of biofilters for sequential removal of hydrogen sulfide and volatile organic compounds (VOCs) from wastewater treatment plant waste air. The biofilter was designed for spatially separated removal of pollutants to mitigate the effects of acid production resulting from hydrogen sulfide oxidation. The inlet section of the upflow units was designated for hydrogen sulfide removal and the second section was designated for VOC removal. Complete removal of hydrogen sulfide (H2S) and methyl tert-butyl ether (MTBE) was accomplished at loading rates of 8.3 g H2S/(m3 x h) (15-second empty bed retention time [EBRT]) and 33 g MTBE/(m3 x h) (60-second EBRT), respectively. In field studies performed at the Hyperion Treatment Plant in Los Angeles, California, excellent removal of hydrogen sulfide, moderate removal of nonchlorinated VOCs such as toluene and benzene, and poor removal of chlorinated VOCs were observed in treating the headworks waste air. During spiking experiments on the headworks waste air, the percentage removals were similar to the unspiked removals when nonchlorinated VOCs were spiked; however, feeding high concentrations of chlorinated VOCs reduced the removal percentages for all VOCs. Thus, biofilters offer a distinct advantage over chemical scrubbers currently used at publicly owned treatment works in that they not only remove odor and hydrogen sulfide efficiently at low cost, but also reduce overall toxicity by partially removing VOCs and avoiding the use of hazardous chemicals.

  12. CONCENTRATIONS OF TOXIC AIR POLLUTANTS IN THE U.S. SIMULATED BY AN AIR QUALITY MODEL

    EPA Science Inventory

    As part of the US National Air Toxics Assessment, we have applied the Community Multiscale Air Quality Model, CMAQ, to study the concentrations of twenty gas-phase, toxic, hazardous air pollutants (HAPs) in the atmosphere over the continental United States. We modified the Carbo...

  13. EP-toxicity testing of mercury removal resin grout

    SciTech Connect

    Mersman, K.E.

    1984-07-18

    To determine which category a waste will fit into, the EPA requires a classification test. The test, EP-toxicity, consists of a physical integrity test followed by an extraction. For the case of the mercury removal resin grout, the mercury concentration in the extract cannot exceed 0.2 mg/L if the waste is to be classified as ``solid waste.`` Otherwise, the waste is classified as ``hazardous.`` Simulated process solutions were used to load the mercury removal resin. The resin was solidified with the addition of cement and water using a formulation based on grout formulations typically used to solidify power reactor ion exchange resins. Envirodyne Engineers of St. Louis, Missouri, an EPA sanctioned laboratory, performed the EP-toxicity test for the two samples. One sample was a blank which was made with unloaded resin. For the formulation tested, the EP-toxicity test results showed that the mercury removal resin grout does not fit into the ``hazardous waste`` category.

  14. Laccase oxidation and removal of toxicants released during combustion processes.

    PubMed

    Prasetyo, Endry Nugroho; Semlitsch, Stefan; Nyanhongo, Gibson S; Lemmouchi, Yahia; Guebitz, Georg M

    2016-02-01

    This study reports for the first time the ability of laccases adsorbed on cellulose acetate to eliminate toxicants released during combustion processes. Laccases directly oxidized and eliminated more than 40% w/v of 14 mM of 1,4-dihydroxybenzene (hydroquinone); 2-methyl-1,4-benzenediol (methylhydroquinone); 1,4-dihydroxy-2,3,5-trimethylbenzene (trimethylhydroquinone); 3-methylphenol (m-cresol); 4-methylphenol (p-cresol); 2-methylphenol (o-cresol); 1,3-benzenediol (resorcinol); 1,2-dihydroxybenzene (catechol); 3,4-dihydroxytoluene (4-methylcatechol) and 2-naphthylamine. Further, laccase oxidized 2-naphthylamine, hydroquinone, catechol, methylhydroquinone and methylcatechol were also able to in turn mediate the elimination of >90% w/v of toxicants which are per-se non-laccase substrates such as 3-aminobiphenyl; 4-aminobiphenyl; benz[a]anthracene; 3-(1-nitrosopyrrolidin-2-yl) pyridine (NNN); formaldehyde; 4-(methyl-nitrosamino-1-(3-pyridyl)-1-butanone (NNK); 2-butenal (crotonaldehyde); nitric oxide and vinyl cyanide (acrylonitrile). These studies demonstrate the potential of laccase immobilized on solid supports to remove many structurally different toxicants released during combustion processes. This system has great potential application for in situ removal of toxicants in the manufacturing, food processing and food service industries. PMID:26408262

  15. Which ornamental plant species effectively remove benzene from indoor air?

    NASA Astrophysics Data System (ADS)

    Liu, Yan-Ju; Mu, Yu-Jing; Zhu, Yong-Guan; Ding, Hui; Crystal Arens, Nan

    Phytoremediation—using plants to remove toxins—is an attractive and cost effective way to improve indoor air quality. This study screened ornamental plants for their ability to remove volatile organic compounds from air by fumigating 73 plant species with 150 ppb benzene, an important indoor air pollutant that poses a risk to human health. The 10 species found to be most effective at removing benzene from air were fumigated for two more days (8 h per day) to quantify their benzene removal capacity. Crassula portulacea, Hydrangea macrophylla, Cymbidium Golden Elf., Ficus microcarpa var. fuyuensis, Dendranthema morifolium, Citrus medica var. sarcodactylis, Dieffenbachia amoena cv. Tropic Snow; Spathiphyllum Supreme; Nephrolepis exaltata cv. Bostoniensis; Dracaena deremensis cv. Variegata emerged as the species with the greatest capacity to remove benzene from indoor air.

  16. Air toxics and asthma: Impacts and end points

    SciTech Connect

    Eschenbacher, W.L.; Holian, A.; Campion, R.J.

    1995-09-01

    The National Urban Air Toxics Research Center (NUATRC) hosted a medical/scientific workshop (February 1994) focused on possible asthma/air toxics relationships, with the results of the NUATRC`s first research contract with the University of Cincinnati as the point of discussion. The workshop explored the impact of various environmental factors, including air toxics, on asthma incidence and exacerbation; and emphasis was placed on future research directions. The information presented at the workshop suggested a possible association of asthma exacerbations with ozone and particulate matter (PM{sub 10}); however, direct relationships between worsening asthma and air toxic ambient levels were not established. Possible respiratory health effects associated with air toxics will require considerably more investigation, especially in the area of human exposure assessment. Two major recommendations for future research resulted form this workshop and an accompanying NUATRC Scientific Advisory Panel meeting: a need for more complete individual personal exposure assessments so that accurate determinations of actual personal exposures to various pollutants can be made; and a need for field experiments utilizing biomarkers of exposure and effect to more accurately assess the extent and variability of the biological effects, if any, of individual air toxics. 8 refs.

  17. Chitosan removes toxic heavy metal ions from cigarette mainstream smoke

    NASA Astrophysics Data System (ADS)

    Zhou, Wen; Xu, Ying; Wang, Dongfeng; Zhou, Shilu

    2013-09-01

    This study investigated the removal of heavy metal ions from cigarette mainstream smoke using chitosan. Chitosan of various deacetylation degrees and molecular weights were manually added to cigarette filters in different dosages. The mainstream smoke particulate matter was collected by a Cambridge filter pad, digested by a microwave digestor, and then analyzed for contents of heavy metal ions, including As(III/V), Pb(II), Cd(II), Cr(III/VI) and Ni(II), by graphite furnace atomic absorption spectrometry (GFAAS). The results showed that chitosan had a removal effect on Pb(II), Cd(II), Cr(III/VI) and Ni(II). Of these, the percent removal of Ni(II) was elevated with an increasing dosage of chitosan. Chitosan of a high deace tylation degree exhibited good binding performance toward Cd(II), Cr(III/VI) and Ni(II), though with poor efficiency for Pb(II). Except As(III/V), all the tested metal ions showed similar tendencies in the growing contents with an increasing chitosan molecular weight. Nonetheless, the percent removal of Cr(III/VI) peaked with a chitosan molecular weight of 200 kDa, followed by a dramatic decrease with an increasing chitosan molecular weight. Generally, chitosan had different removal effects on four out of five tested metal ions, and the percent removal of Cd(II), Pb(II), Cr(III/VI) and Ni(II) was approximately 55%, 45%, 50%, and 16%, respectively. In a word, chitosan used in cigarette filter can remove toxic heavy metal ions in the mainstream smoke, improve cigarette safety, and reduce the harm to smokers.

  18. The National Near-Road Mobile Source Air Toxics Study

    EPA Science Inventory

    Recently, much attention has been directed at understanding the impact of mobile sources on near-road air quality, especially PM and its components, NOx and CO, but little information exists for mobile source air toxics (MSATs). MSATs of interest to this project are 1,3-butadiene...

  19. Evolution of the Air Toxics under the Big Sky Program

    ERIC Educational Resources Information Center

    Marra, Nancy; Vanek, Diana; Hester, Carolyn; Holian, Andrij; Ward, Tony; Adams, Earle; Knuth, Randy

    2011-01-01

    As a yearlong exploration of air quality and its relation to respiratory health, the "Air Toxics Under the Big Sky" program offers opportunities for students to learn and apply science process skills through self-designed inquiry-based research projects conducted within their communities. The program follows a systematic scope and sequence…

  20. Thoratec left ventricular assist device removal after toxic myocarditis.

    PubMed

    Leontiadis, Evangelos; Morshuis, Michiel; Arusoglu, Latif; Cobaugh, Dagmar; Koerfer, Reiner; El-Banayosy, Aly

    2008-12-01

    The clinical manifestation and natural history of myocarditis range is variable from asymptomatic stages to intractable circulatory compromise and death. Supportive therapy is paramount in the treatment of this condition. The use of mechanical circulatory support as bridge-to-recovery or bridge-to-transplantation in cases of cardiovascular collapse is often the only therapeutic option for these patients. We report the case of an adolescent boy with toxic myocarditis, due to cannabis abuse, who was supported with a Thoratec left ventricular assist device (Thoratec Laboratories Corp, Pleasanton, CA) for 96 days before device removal. PMID:19022028

  1. Screening of physical-chemical methods for removal of organic material, nitrogen and toxicity from low strength landfill leachates.

    PubMed

    Marttinen, S K; Kettunen, R H; Sormunen, K M; Soimasuo, R M; Rintala, J A

    2002-02-01

    Physical-chemical methods have been suggested for the treatment of low strength municipal landfill leachates. Therefore, applicability of nanofiltration and air stripping were screened in laboratory-scale for the removal of organic matter, ammonia, and toxicity from low strength leachates (NH4-N 74-220 mg/l, chemical oxygen demand (COD) 190-920 mg O2/l, EC50 = 2-17% for Raphidocelis subcapitata). Ozonation was studied as well, but with the emphasis on enhancing biodegradability of leachates. Nanofiltration (25 degrees C) removed 52-66% of COD and 27-50% of ammonia, the latter indicating that ammonia may in part have been present as ammonium salt complexes. Biological pretreatment enhanced the overall COD removal. Air stripping (24 h at pH 11) resulted in 89% and 64% ammonia removal at 20 and 6 degrees C, respectively, the stripping rate remaining below 10 mg N/l h. COD removals of 4-21% were obtained in stripping. Ozonation (20 degrees C) increased the concentration of rapidly biodegradable COD (RBCOD), but the proportion of RBCOD of total COD was still below 20% indicating poor biological treatability. The effect of the different treatments on leachate toxicity was assessed with the Daphnia acute toxicity test (Daphnia magna) and algal growth inhibition test (Raphidcocelis subcapitata). None of the methods was effective in toxicity removal. By way of comparison, treatment in a full-scale biological plant decreased leachate toxicity to half of the initial value. Although leachate toxicity significantly correlated with COD and ammonia in untreated and treated leachate, in some stripping and ozonation experiments toxicity was increased in spite of COD and ammonia removals.

  2. Air toxics and asthma: impacts and end points.

    PubMed

    Eschenbacher, W L; Holian, A; Campion, R J

    1995-09-01

    The National Urban Air Toxics Research Center (NUATRC) hosted a medical/scientific workshop focused on possible asthma/air toxics relationships, with the results of the NUATRC's first research contract with the University of Cincinnati as the point of discussion. The workshop was held at the Texas Medical Center on 4 February 1994 and featured presentations by distinguished academic, government, and industry scientists. This one-day session explored the impact of various environmental factors, including air toxics, on asthma incidence and exacerbation; an emphasis was placed on future research directions to be pursued in the asthma/air toxics area. A key research presentation on the association of air toxics and asthma, based on the study sponsored by NUATRC, was given by Dr. George Leikauf of the University of Cincinnati Medical Center. Additional presentations were made by H. A. Boushey, Jr., Cardiovascular Research Institute/University of California at San Francisco, who spoke on of the Basic Mechanisms of Asthma; K. Sexton, U.S. Environmental Protection Agency, who spoke on hazardous air pollutants: science/policy interface; and D. V. Bates, Department of Health Care and Epidemiology at the University of British Columbia, who spoke on asthma epidemiology. H. Koren, U.S. Environmental Protection Agency, and M. Yeung, of the Respiratory Division/University of British Columbia, Vancouver General Hospital, discussed occupational health impacts on asthma. Doyle Pendleton, Texas Natural Resource Conservation Commission, reviewed air quality measurements in Texas. The information presented at the workshop suggested a possible association of asthma exacerbations with ozone and particulate matter (PM10); however, direct relationships between worsening asthma and air toxic ambient levels were not established. Possible respiratory health effects associated with air toxics will require considerably more investigation, especially in the area of human exposure assessment

  3. Effects of UV irradiation on humic acid removal by ozonation, Fenton and Fe⁰/air treatment: THMFP and biotoxicity evaluation.

    PubMed

    Wei, Ming-Chi; Wang, Kai-sung; Hsiao, Tung-En; Lin, I-Chen; Wu, Hui-Ju; Wu, Yuh-Luan; Liu, Pey-Horng; Chang, Shih-Hsien

    2011-11-15

    Effects of UV irradiation on humic acid (HA) removal by Fe(0)/air, ozonation and Fenton oxidation were investigated. The trihalomethane forming potential (THMFP) and toxicity of treated solutions were also evaluated. The experimental conditions were ozone of 21 mg min(-1), H(2)O(2) of 8 × 10(-4)M, Fe(0) of 20 g L(-1), air flow of 5 L min(-1), and UVC of 9 W. Results indicated that Fe(0)/air rapidly removed HA color (>99%) and COD (90%) within 9 min. 51-81% of color and 43-50% of COD were removed by ozonation and Fenton oxidation after 60 min. Both UV enhanced ozone and Fenton oxidation removed HA, but the Fe(0)/air process did not. Spectrum results showed all processes effectively diminished UV-vis spectra, except for ozonation. The THMFP of Fe(0)/air-treated solution (114 μg L(-1)) was much lower than those of Fenton- (226 μg L(-1)) and ozonation-treated solutions (499 μg L(-1)). Fe(0)/air with UV irradiation obviously increased the THMFP of treated solution (502 μg L(-1)). The toxicity results obtained from Vibrio fischeri light inhibition test indicated that the toxicity of Fe(0)/air-treated solution (5%) was much lower than that of ozonation- (33%) and Fenton-treated solutions (31%). Chlorination increased the solution toxicity. The correlation between biotoxicity and chloroform in the chlorinated solution was insignificant.

  4. AIR QUALITY MODELING OF PM AND AIR TOXICS AT NEIGHBORHOOD SCALES

    EPA Science Inventory

    The current interest in fine particles and toxics pollutants provide an impetus for extending air quality modeling capability towards improving exposure modeling and assessments. Human exposure models require information on concentration derived from interpolation of observati...

  5. Integrating the federal and California air toxics programs

    SciTech Connect

    Fletcher, R.D.

    1996-12-31

    This paper discusses California`s existing air toxic program and presents an approach for integrating the program with the federal program. Competitiveness can be enhanced by a strong federal program, but a smooth integration is essential to maintain an effective state program. Flexibility and good communication are essential to ensure a smooth integration and successful implementation.

  6. AIR TOXICS EMISSIONS FROM A VINYL SHOWER CURTAIN

    EPA Science Inventory

    The paper reports results of both static and dynamic chamber tests conducted to evaluate emission characteristics of air toxics from a vinyl shower Curtain. (NOTE: Due to the relatively low price and ease of installation, vinyl shower curtains have been widely used in bathrooms i...

  7. Uneven Magnitude of Disparities in Cancer Risks from Air Toxics

    PubMed Central

    James, Wesley; Jia, Chunrong; Kedia, Satish

    2012-01-01

    This study examines race- and income-based disparities in cancer risks from air toxics in Cancer Alley, LA, USA. Risk estimates were obtained from the 2005 National Air Toxics Assessment and socioeconomic and race data from the 2005 American Community Survey, both at the census tract level. Disparities were assessed using spatially weighted ordinary least squares (OLS) regression and quantile regression (QR) for five major air toxics, each with cancer risk greater than 10−6. Spatial OLS results showed that disparities in cancer risks were significant: People in low-income tracts bore a cumulative risk 12% more than those in high-income tracts (p < 0.05), and those in black-dominant areas 16% more than in white-dominant areas (p < 0.01). Formaldehyde and benzene were the two largest contributors to the disparities. Contributions from emission sources to disparities varied by compound. Spatial QR analyses showed that magnitude of disparity became larger at the high end of exposure range, indicating worsened disparity in the poorest and most highly concentrated black areas. Cancer risk of air toxics not only disproportionately affects socioeconomically disadvantaged and racial minority communities, but there is a gradient effect within these groups with poorer and higher minority concentrated segments being more affected than their counterparts. Risk reduction strategies should target emission sources, risk driver chemicals, and especially the disadvantaged neighborhoods. PMID:23208297

  8. Methods for determination of toxic organic compounds in air

    SciTech Connect

    Winberry, W.T. Jr.

    1990-01-01

    This paper provides environmental regulatory agencies, industry, and other interested parties with specific, standardized sampling and analysis procedures for toxic organic compounds in air. Compounds include Volatile Organic Compounds, Organochlorine Pesticides and PCBs, Aldehydes and Ketones, Phosgene, N-Nitrosodimethylamine, Phenol and Methylphenols (Cresols), Polychlorinated Dibenzo-p-Dioxins (PCDDs), Formaldehyde, Non-Methane Organic Compounds (NMOCs) and Polynuclear Aromatic Hydrocarbons (PAHs).

  9. POPULATION EXPOSURE AND DOSE MODEL FOR AIR TOXICS: A BENZENE CASE STUDY

    EPA Science Inventory

    The EPA's National Exposure Research Laboratory (NERL) is developing a human exposure and dose model called the Stochastic Human Exposure and Dose Simulation model for Air Toxics (SHEDS-AirToxics) to characterize population exposure to air toxics in support of the National Air ...

  10. Measurement of air toxics using extractive FTIR spectroscopy

    SciTech Connect

    Lacoss, J.P.; Ogle, L.D.; Shareef, G.S.

    1995-12-31

    In response to the 1990 Clean Air Act Amendments, the Gas Research Institute (GRI) is investigating air toxics emissions from natural gas industry sources. Included in this effort are measurements from internal combustion engines, one of the source categories targeted by U.S. Environmental Protection Agency (EPA) for development of maximum achievable control technology (MACT) based regulations by the year 2000. Formaldehyde and other aldehydes are the air toxics potentially present in engine exhaust. Since there are no EPA approved methods available for quantifying aldehydes in engine exhaust, GRI initiated a field test to validate an extractive Fourier transform infrared spectroscopy (FTIR) based method according to U.S. EPA Method 301 {open_quotes}Field Validation of Pollutant Measurement Methods for Various Media{close_quotes}. The extended paper presents the results of this validation testing for formaldehyde, acetaldehyde, and acrolein conducted to support this validation testing.

  11. Toxic air contaminants in urban atmospheres: Experience in California

    NASA Astrophysics Data System (ADS)

    Seiber, James N.

    In addition to the criteria gaseous and particulate air pollutants which have been the subject of intensive regulation for many years in the U.S., there exists in the atmosphere of cities and surrounding areas a number of trace toxic contaminants which are of increasing public health and regulatory concern. In California, these Toxic Air Contaminants (TACs) are assessed and regulated by a multi-step process required by legislation. Risk assessment for chemicals which are considered potential TACs involves the gathering and analysis of information on emissions, exposures, toxicology, and epidemiology by two California Agencies, the Air Resources Board and Department of Health Services (now linked by the California Environmental Protection Agency) and an independent Scientific Review Panel. Eighteen chemicals have been designated as TACs since the process started in 1982, including perchloroethylene, formaldehyde, vinyl chloride, and 1,3-butadiene which are mentioned in some detail in this review. Future challenges for risk assessment and management are posed by such issues as gross mixtures, for example, from products of incomplete combustion; transport and deposition out of the originating air basin; contributions of natural sources to ambient levels; and the impact of the list of 189 hazardous air pollutants in the 1990 U.S. Clean Air Act Amendments on California's TAC identification-regulation process. The issues involved in a vigorous pursuit of risk reduction from TACs are discussed based upon experience in California.

  12. Estimating service lives of air-purifying respirator cartridges for reactive gas removal.

    PubMed

    Wood, Gerry O

    2005-08-01

    A mathematical model has been developed to estimate service lives of air-purifying respirator cartridges that remove gases reactively from flowing air. Most gases, because of their high volatility and low polarizability, are not effectively removed by physical adsorption on activated carbon. Models previously developed for toxic organic vapors cannot estimate service lives of cartridges for toxic gases. Often, an activated carbon is impregnated with a chemical to enhance gas removal by chemical reaction(s). The kinds of reactions, types and amounts of impregnants, and effects of the presence of water vary; therefore, the model requires user inputs of gas capacity and water effect parameters. Ideally, these should be available from manufacturers of the cartridges. If they are not, they can be extracted from measured breakthrough times using this model. The key to this model is the observation that adsorption rates of gases can be adequately quantified by the same correlations that have been reported for organic vapors. The resulting model has been used to correlate and predict breakthrough times for several common toxic gases. PMID:16012083

  13. Mobile Source Air Toxics Rule (released in AEO2008)

    EIA Publications

    2008-01-01

    On February 9, 2007, the Environmental Protection Agency (EPA) released its MSAT2 rule, which will establish controls on gasoline, passenger vehicles, and portable fuel containers. The controls are designed to reduce emissions of benzene and other hazardous air pollutants. Benzene is a known carcinogen, and the EPA estimates that mobile sources produced more than 70% of all benzene emissions in 1999. Other mobile source air toxics, including 1,3-butadiene, formaldehyde, acetaldehyde, acrolein, and naphthalene, also are thought to increase cancer rates or contribute to other serious health problems.

  14. Air toxics risk standards: are we addressing the real problems?

    SciTech Connect

    Laurie Miller; Richard Becker; Ted Cromwell

    2005-06-01

    Cost-effective risk reductions from major stationary emission sources have seen significant progress. EPA and state data demonstrate that their programs have dramatically reduced emissions and risk from these sources. Analyses indicate that the next generation of risk reductions for stationary sources will be provide little risk reduction, but will be much more costly and more challenging from a policy perspective. Facing these tough choices, EPA and state regulators should, with stakeholder input, be developing scientifically driven and cost-effective approaches to provide the public with honest answers and results. Air toxics risk policies and programs must prioritize and address significant remaining air toxics risks, educate and communicate to the public about the decision alternatives, build support for a holistic approach and openly communicate results. 6 refs.

  15. Air toxics emissions from gas-fired engines

    SciTech Connect

    Meeks, H.N. Jr. )

    1992-07-01

    In 1190, 14 natural-gas-fired internal combustion engines (ICE's) in oilfield service were tested in Santa Barbara County, CA, to satisfy California air toxics legislation. The combustion exhaust was tested for formaldehyde, acetaldehyde, acrolein, benzene, toluene, xylences, naphthalene, and polycyclic aromatic hydrocarbons. The fuel was tested for aromatics to enable calculation of destruction efficiencies. Two-stroke and four-stroke engines were tested. Four-stroke engines ranging from 39 to 208 hp were used in pumping unit and constant load service. Emissions from four-stroke engines were unrelated to size and service. The two-stroke engines produced considerably higher emissions than the four-stroke engines. This paper reports that test results indicate natural-gas-fired ICE's produce toxic substances in small amounts. Formaldehyde and benzene dominated the toxic emission profile.

  16. Analytical model for contaminant mass removal by air sparging

    SciTech Connect

    Rabideau, A.J.; Blayden, J.M.

    1998-12-31

    An analytical model was developed to predict the removal of volatile organic compounds (VOCs) from ground water by air sparging (AS). The model treats the air sparging zone as a completely mixed reactor subject to the removal of dissolved contaminants by volatilization, advection, and first-order decay. Nonequilibrium desorption is approximated as a first-order mass transfer process. The model reproduces the tailing and rebound behavior often observed at AS sites, and would normally require the estimation of three site-specific parameters. Dimensional analysis demonstrates that predicting tailing can be interpreted in terms of kinetic desorption or diffusion of aqueous phase contaminants into discrete air channels. Related work is ongoing to test the model against field data.

  17. Toxicity of Silver Nanoparticles at the Air-Liquid Interface

    PubMed Central

    Holder, Amara L.; Marr, Linsey C.

    2013-01-01

    Silver nanoparticles are one of the most prevalent nanomaterials in consumer products. Some of these products are likely to be aerosolized, making silver nanoparticles a high priority for inhalation toxicity assessment. To study the inhalation toxicity of silver nanoparticles, we have exposed cultured lung cells to them at the air-liquid interface. Cells were exposed to suspensions of silver or nickel oxide (positive control) nanoparticles at concentrations of 2.6, 6.6, and 13.2 μg cm−2 (volume concentrations of 10, 25, and 50 μg ml−1) and to 0.7 μg cm−2 silver or 2.1 μg cm−2 nickel oxide aerosol at the air-liquid interface. Unlike a number of in vitro studies employing suspensions of silver nanoparticles, which have shown strong toxic effects, both suspensions and aerosolized nanoparticles caused negligible cytotoxicity and only a mild inflammatory response, in agreement with animal exposures. Additionally, we have developed a novel method using a differential mobility analyzer to select aerosolized nanoparticles of a single diameter to assess the size-dependent toxicity of silver nanoparticles. PMID:23484109

  18. Biochars made from agro-industrial by-products remove chlorine and lower water toxicity

    NASA Astrophysics Data System (ADS)

    Tzachristas, Andreas; Xirou, Maria; Manariotis, Ioannis D.; Dailianis, Stefanos; Karapanagioti, Hrissi K.

    2016-04-01

    Chlorination is the most common disinfection process for water and treated wastewater. For the industrial use of water in food production, chlorine can add undesired taste and odor to the final product. For this reason, dechlorination is desired for food industries that use municipal tap water. For treated wastewater discharge or reuse, chlorine can be toxic to the receiving aqueous systems and to the irrigated plants. In both the above cases, dechlorination is also required. Traditionally activated carbon has been used as the ideal material for the removal of chlorine. The main mechanisms that describe the interaction between activated carbon and HOCl or OCl- are described by the following equations (AWWA, 1990): HOCl + C* → C*O + H+ + Cl- (1), OCl- + C* → C*O + Cl- (2) Where C* and C*O represent the activated carbon surface and a surface oxide, respectively. The present study proposes the use of agro-industrial by-products for the production of biochars that will be used for dechlorination of tap-water used for food-industry production. Different raw materials such as malt spent rootlets, coffee residue, olive and grape seeds, etc. are used for the production of biochar. Various temperatures and air-to-solid ratios are tested for optimizing biochar production. Batch tests as well as a column test are employed to study the dechlorination efficiency and kinetics of the different raw and biochar materials as well as those of commercial activated carbons. As chlorine concentration increases the removal also increases linearily. After 1 and 24 hours of contact the chlorine relative removal efficiencies for the biochar made from olive seeds are 50 and 77 ± 4%, respectively. It seems that the removal kinetics are faster during the first hour; then, removal continues but with a slower rate. Most of the biochars tested (with 3 mg of solid in 20 mL of chlorine solution at initial concentration Co=1.5 mg/L) demonstrated removal efficiencies with an average of 9.4 ± 0

  19. Evaluation of Filters for Removal of Bacteriophages from Air1

    PubMed Central

    Washam, C. J.; Black, C. H.; Sandine, W. E.; Elliker, P. R.

    1966-01-01

    Glass wool, nonabsorbent cotton, fiberglass filter medium, and a commercial absolute filter were tested for effectiveness in removing aerosolized bacterial viruses under low flow rate (1 ft3/min) and high flow rate (10 to 25 ft3/min) air-flow conditions. Special equipment was designed for measurement of filter efficiencies under the two air-flow conditions. Under low air-flow rate test conditions, glass wool was only 98.543 to 99.83% efficient, whereas cotton (five layers), fiberglass medium (three layers), and the commercial absolute filter were at least 99.900, 99.999, and 99.999 efficient, respectively. Glass wool and cotton were not used under higher air-flow conditions because they were difficult to assemble in leak-tight filters. The commercial absolute filter and fiberglass medium (three layers) were at least 99.990 and 99.999% efficient, respectively, under the higher air flow conditions. A stainless-steel filter of simple design and fitted with three layers of fiberglass medium was found to be greater than 99.999% efficient in removing high concentrations (20,000 to 70,000 plaque-forming units per cubic foot) of aerosolized bacteriophages from air moving at a low flow rate (1 ft3/min). Use of this filter on pressure-vacuum tanks in the fermentation industry is suggested. Several other uses of such a filter are proposed. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 PMID:5927020

  20. Characterizing Air Toxics from Oil Field Operations in Los Angeles

    NASA Astrophysics Data System (ADS)

    McCarthy, M. C.; Brown, S. G.; DeWinter, J. L.; Bai, S.; O'Brien, T.; Vaughn, D.; Peltier, R.; Soltis, J.; Field, R. A.; Murphy, S. M.; Roberts, P. T.

    2014-12-01

    The Inglewood Oil Field in urban Los Angeles has been in operation for more than 70 years. Neighborhoods surrounding the oil field are concerned with the potential emissions of air toxics from oil field operations. The Baldwin Hills Air Quality Study focused on (1) quantifying air toxics concentrations originating from the Inglewood Oil Field operations, including drilling and well workovers, and (2) assessing the health risk of both acute and chronic exposure to air toxics emitted from oil field operations. Key pollutants identified for characterization included diesel particulate matter (DPM), cadmium, benzene, nickel, formaldehyde, mercury, manganese, acrolein, arsenic, and lead. The field study began in November 2012 and ended in November 2013. Four types of instruments were used to characterize oil field operations: (1) Aethalometers to measure black carbon (BC; as a proxy for DPM); (2) X-ray fluorescence spectrometer (XRF) for metals; (3) Proton-Transfer-Reaction Time-of-Flight Mass Spectrometry (PTR-TOFMS) for volatile organic compounds; and (4) meteorological sensors to help assess the wind patterns, temperature, and humidity that influence pollutant concentrations. Overall concentrations of most of the species measured in the study were quite low for an urban area. We determined that there were statistically significant increases in concentrations of DPM associated with oil field operations when winds were from the west-southwest. BC concentrations increased by 0.036 to 0.056 μg/m3, on average, when winds originated from the west-southwest, compared to annual mean BC concentrations of approximately 0.67 μg/m3. West-southwest winds occurred 53% of the time during the study. No other pollutants showed strong statistical evidence of chronic or acute risk from oil field operations.

  1. Air toxic emissions from snowmobiles in Yellowstone National Park.

    PubMed

    Zhou, Yong; Shively, David; Mao, Huiting; Russo, Rachel S; Pape, Bruce; Mower, Richard N; Talbot, Robert; Sive, Barkley C

    2010-01-01

    A study on emissions associated with oversnow travel in Yellowstone National Park (YNP) was conducted for the time period of February 13-16, 2002 and February 12-16, 2003. Whole air and exhaust samples were characterized for 85 volatile organic compounds using gas chromatography. The toxics including benzene, toluene, ethylbenzene, xylenes (p-, m-, and o-xylene), and n-hexane, which are major components of two-stroke engine exhaust, show large enhancements during sampling periods resulting from increased snowmobile traffic. Evaluation of the photochemical history of air masses sampled in YNP revealed that emissions of these air toxics were (i) recent, (ii) persistent throughout the region, and (iii) consistent with the two-stroke engine exhaust sample fingerprints. The annual fluxes were estimated to be 0.35, 1.12, 0.24, 1.45, and 0.36 Gg yr(-1) for benzene, toluene, ethylbenzene, xylenes, and n-hexane, respectively, from snowmobile usage in YNP. These results are comparable to the flux estimates of 0.23, 0.77, 0.17, and 0.70 Gg yr(-1) for benzene, toluene, ethylbenzene, and xylenes, respectively, that were derived on the basis of (i) actual snowmobile counts in the Park and (ii) our ambient measurements conducted in 2003. Extrapolating these results, annual emissions from snowmobiles in the U.S. appear to be significantly higher than the values from the EPA National Emissions Inventory (1999). Snowmobile emissions represent a significant fraction ( approximately 14-21%) of air toxics with respect to EPA estimates of emissions by nonroad vehicles. Further investigation is warranted to more rigorously quantify the difference between our estimates and emission inventories.

  2. Investigations on Chlorophytum comosum ability to remove toluene from air in a closed environment

    NASA Astrophysics Data System (ADS)

    Bulteau, G.; Lakel, A.

    Plants play a major role in bioregenerative systems for air and water supplies. They may also contribute to the removal of volatile organic compounds (VOC) from the air in a closed environment, based on the ability to absorb toxic compounds and to detoxify them. The aim of our work was to study the capabilities of Chlorophytum comosum for toluene removal and to identify the main parts of the plants which are responsible for the elimination. A 1-m3 sealed chamber was designed and built in 8-mm window glass assembled with UV-polymerized glue. It was equipped with one internal fan for air mixing. The other materials (low-emitting and low-adsorptive) were aluminium and PTFE. A cooling system was also used to regulate humidity content which was monitored continuously as well as temperature and carbon dioxide concentration. Experiments were carried out in this chamber with Chlorophytum comosum plants exposed to an initial concentration of 11.5x103 μg toluene m-3. Pollutant concentration was measured every five minutes during several days. Toluene removal was studied in various configurations (potting media, hydroponic conditions{ldots}) in order to document the level of contribution of each component (leaves, roots, microorganisms and soil) of the potted plants. Results show that 54 % of toluene was removed in 72 h with the whole potted plant. A large participation of the soil in the purification process was noticed whereas foliage seemed to have little effect at the light intensity used in the experiments. Moreover, the tests realized with both natural and sterilized soils suggest that soil bacteria (in potting media) play a significant role in the removal process showing that soil and its microorganisms may have complementary roles in the elimination phenomena. Detoxifying function of potted plants could find current applications in improving air quality, in particular indoor air from domestic buildings.

  3. Removal of formaldehyde from air using functionalized silica supports.

    PubMed

    Ewlad-Ahmed, Abdunaser M; Morris, Michael A; Patwardhan, Siddharth V; Gibson, Lorraine T

    2012-12-18

    This paper demonstrates the use of functionalized meso-silica materials (MCM-41 or SBA-15) as adsorbents for formaldehyde (H₂CO) vapor from contaminated air. Additionally new green nanosilica (GNs) materials were prepared via a bioinspired synthesis route and were assessed for removal of H₂CO from contaminated indoor air. These exciting new materials were prepared via rapid, 15 min, environmentally friendly synthesis routes avoiding any secondary pollution. They provided an excellent platform for functionalization and extraction of H₂CO demonstrating similar performance to the conventional meso-silica materials. To the authors' knowledge this is the first reported practical application of this material type. Prior to trapping, all materials were functionalized with amino-propyl groups which led to chemisorption of H₂CO; removing it permanently from air. No retention of H₂CO was achieved with nonfunctionalized material and it was observed that best extraction performance required a dynamic adsorption setup when compared to passive application. These results demonstrate the first application of GNs as potential adsorbents and functionalized meso-silica for use in remediation of air pollution in indoor air.

  4. Removal of formaldehyde from air using functionalized silica supports.

    PubMed

    Ewlad-Ahmed, Abdunaser M; Morris, Michael A; Patwardhan, Siddharth V; Gibson, Lorraine T

    2012-12-18

    This paper demonstrates the use of functionalized meso-silica materials (MCM-41 or SBA-15) as adsorbents for formaldehyde (H₂CO) vapor from contaminated air. Additionally new green nanosilica (GNs) materials were prepared via a bioinspired synthesis route and were assessed for removal of H₂CO from contaminated indoor air. These exciting new materials were prepared via rapid, 15 min, environmentally friendly synthesis routes avoiding any secondary pollution. They provided an excellent platform for functionalization and extraction of H₂CO demonstrating similar performance to the conventional meso-silica materials. To the authors' knowledge this is the first reported practical application of this material type. Prior to trapping, all materials were functionalized with amino-propyl groups which led to chemisorption of H₂CO; removing it permanently from air. No retention of H₂CO was achieved with nonfunctionalized material and it was observed that best extraction performance required a dynamic adsorption setup when compared to passive application. These results demonstrate the first application of GNs as potential adsorbents and functionalized meso-silica for use in remediation of air pollution in indoor air. PMID:23181357

  5. Air toxics evaluation of ABB Combustion Engineering Low-Emission Boiler Systems

    SciTech Connect

    Wesnor, J.D.

    1993-10-26

    The specific goals of the program are to identify air toxic compounds that might be emmitted from the new boiler with its various Air Pollution Control device for APCD alternatives in levels of regulatory concern. For the compounds thought to be of concern, potential air toxic control methodologies will be suggested and a Test Protocol will be written to be used in the Proof of Concept and full scale tests. The following task was defined: Define Replations and Standards; Identify Air Toxic Pollutants of Interest to Interest to Utility Boilers; Assesment of Air Toxic By-Products; State of the Art Assessment of Toxic By-Product Control Technologies; and Test Protocol Definition.

  6. Removal of Toxic English Teaching & Learning Styles in China

    ERIC Educational Resources Information Center

    Jian-xiang, Geng

    2007-01-01

    There are a few unique English teaching and learning styles among some Chinese teachers and learners, which affect their work efficiency or are toxic to their work and study. Some suggestions on getting rid of toxic teaching and learning styles are necessary to the improvement of teaching and learning efficiency. Cultivating healthy styles for…

  7. [Toxic fungi in Buenos Aires City and surroundings].

    PubMed

    Romano, Gonzalo M; Iannone, Leopoldo; Novas, María V; Carmarán, Cecilia; Romero, Andrea I; López, Silvia E; Lechner, Bernardo E

    2013-01-01

    In Facultad de Ciencias Exactas y Naturales,Universidad de Buenos Aires there is a service called Servicio de Identificación de Hongos Tóxicos, directed by researchers of the Program of Medicinal Plants and Fungi Involved in Biological Degradation (PROPLAME-PRHIDEB, CONICET) that assist hospitals and other health establishments, identifying the different samples of fungi and providing information about their toxicity, so that patients can receive the correct treatment. The objective of the present study was to analyze all the cases received from 1985 to 2012. This analysis permitted the confection of a table identifying the most common toxic species. The information gathered revealed that 47% of the patients were under 18 years of age and had eaten basidiomes; the remaining 53% were adults who insisted that they were able to distinguish edible from toxic mushrooms. Chlorophyllum molybdites turned out to be the main cause of fungal intoxication in Buenos Aires, which is commonly confused with Macrolepiota procera, an edible mushroom. In the second place Amanita phalloides was registered, an agaric known to cause severe symptoms after a long period of latency (6-10 hours), and which can lead to hepatic failure even requiring a transplant to prevent severe internal injuries or even death, is not early and correctly treated.

  8. [Toxic fungi in Buenos Aires City and surroundings].

    PubMed

    Romano, Gonzalo M; Iannone, Leopoldo; Novas, María V; Carmarán, Cecilia; Romero, Andrea I; López, Silvia E; Lechner, Bernardo E

    2013-01-01

    In Facultad de Ciencias Exactas y Naturales,Universidad de Buenos Aires there is a service called Servicio de Identificación de Hongos Tóxicos, directed by researchers of the Program of Medicinal Plants and Fungi Involved in Biological Degradation (PROPLAME-PRHIDEB, CONICET) that assist hospitals and other health establishments, identifying the different samples of fungi and providing information about their toxicity, so that patients can receive the correct treatment. The objective of the present study was to analyze all the cases received from 1985 to 2012. This analysis permitted the confection of a table identifying the most common toxic species. The information gathered revealed that 47% of the patients were under 18 years of age and had eaten basidiomes; the remaining 53% were adults who insisted that they were able to distinguish edible from toxic mushrooms. Chlorophyllum molybdites turned out to be the main cause of fungal intoxication in Buenos Aires, which is commonly confused with Macrolepiota procera, an edible mushroom. In the second place Amanita phalloides was registered, an agaric known to cause severe symptoms after a long period of latency (6-10 hours), and which can lead to hepatic failure even requiring a transplant to prevent severe internal injuries or even death, is not early and correctly treated. PMID:24152394

  9. Vinyl chloride removal from an air stream by biotrickling filter.

    PubMed

    Faraj, S H Esmaeili; Esfahany, M Nasr; Kadivar, M; Zilouei, H

    2012-01-01

    A biofiltration process was used for degradation of vinyl chloride as a hazardous material in the air stream. Three biotrickling filters in series-parallel allowing uniform feed and moisture distribution all over the bed were used. Granular activated carbon mixed with compost was employed as carrier bed. The biological culture consisted of mixture of activated sludge from PVC wastewater treatment plant. Concurrent flow of gas and liquid was used in the bed. Results indicated that during the operation period of 110 days, the biotrickling bed was able to remove over 35% of inlet vinyl chloride. Maximum elimination capacity was calculated to be 0.56 g.m(-3).hr(-1). The amount of chlorine accumulated in the circulating liquid due to the degradation of vinyl chloride was measured to be equal to the vinyl chloride removed from the air stream.

  10. Tropospheric gas at potentially toxic levels in air

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Atreyee

    2012-08-01

    Forest fires and emission of air pollutants, such as fumes from vehicles running on diesel and slow burning of coal and charcoal, release isocyanic acid in the troposphere. In 2011, scientists first detected isocyanic acid in the ambient atmosphere at levels toxic to human populations; at concentrations exceeding 1 part per billion by volume (ppbv), human beings could experience tissue decay when exposed to the toxin. For the first time, using a chemical transport model designed to estimate the distribution and budget of isocyanic acid in the troposphere, Young et al. showed that in several parts of the world, local emissions may increase the concentration of isocyanic acid in the ambient atmosphere, thereby exposing large populations to potentially toxic levels of the acid.

  11. Regional Air Toxics Modeling in California's San Francisco Bay Area

    NASA Astrophysics Data System (ADS)

    Martien, P. T.; Tanrikulu, S.; Tran, C.; Fairley, D.; Jia, Y.; Fanai, A.; Reid, S.; Yarwood, G.; Emery, C.

    2011-12-01

    Regional toxics modeling conducted for California's San Francisco Bay Area (SFBA) estimated potential cancer risk from diesel particulate matter (DPM) and four key reactive toxic gaseous pollutants (1,3-butadiene, benzene, formaldehyde, and acetaldehyde). Concentrations of other non-cancerous gaseous toxic air contaminants, including acrolein, were also generated. In this study, meteorological fields generated from July and December periods in 2000 and emissions from 2005 provided inputs to a three-dimensional air quality model at high spatial resolution (1x1 km^2 grid), from which a baseline set of annual risk values was estimated. Simulated risk maps show highest annual average DPM concentrations and cancer risks were located near and downwind of major freeways and near the Port of Oakland, a major container port in the area. Population weighted risks, using 2000 census data, were found to be highest in highly urbanized areas adjacent to significant DPM sources. For summer, the ratio of mean measured elemental carbon to mean modeled DPM was 0.78, conforming roughly to expectations. But for winter the ratio is 1.13, suggesting other sources of elemental carbon, such as wood smoke, are important. Simulated annual estimates for benzene and 1-3, butadiene compared well to measured annual estimates. Simulated acrolein and formaldehyde significantly under-predicted observed values. Simulations repeated using projected 2015 toxic emissions predicted that potential cancer risk dropped significantly in all areas throughout the SFBA. Emissions estimates for 2015 included the State of California's recently adopted on-road truck rule. Emission estimates of DPM are projected to drop about 70% between 2005 and 2015 in the SFBA, with a commensurate reduction in potential cancer risks. However, due to projected shifts in population during this period, with urban densification close to DPM sources outpacing emission reductions, there are some areas where population-weighted risks

  12. Ultrafine particle removal and generation by portable air cleaners

    NASA Astrophysics Data System (ADS)

    Waring, Michael S.; Siegel, Jeffrey A.; Corsi, Richard L.

    Portable air cleaners can both remove and generate pollutants indoors. To investigate these phenomena, we conducted a two-phase investigation in a 14.75 m 3 stainless steel chamber. In the first phase, particle size-resolved (12.6-514 nm diameter) clean air delivery rates (CADR) and efficiencies were determined, as were ozone emission rates, for two high-efficiency particle arresting (HEPA) filters, one electrostatic precipitator with a fan, and two ion generators without fans. The two HEPA air cleaners had count average CADR (standard deviation) of 188 (30) and 324 (44) m 3 h -1; the electrostatic precipitator 284 (62) m 3 h -1; and the two ion generators 41 (11) and 35 (13) m 3 h -1. The electrostatic precipitator emitted ozone at a rate of 3.8±0.2 mg h -1, and the two ion generators 3.3±0.2 and 4.3±0.2 mg h -1. Ozone initiates reactions with certain unsaturated organic compounds that produce ultrafine and fine particles, carbonyls, other oxidized products, and free radicals. During the second phase, five different ion generators were operated separately in the presence of a plug-in liquid or solid air freshener, representing a strong terpene source. For air exchange rates of between 0.49 and 0.96 h -1, three ion generators acted as steady-state net particle generators in the entire measured range of 4.61-157 nm, and two generated particles in the range of approximately 10 to 39-55 nm. Terpene and aldehyde concentrations were also sampled for one ion generator, and concentrations of terpenes decreased and formaldehyde increased. Given these results, the pollutant removal benefits of ozone-generating air cleaners may be outweighed by the generation of indoor pollution.

  13. Addressing community concerns about asthma and air toxics.

    PubMed Central

    White, Mary C; Berger-Frank, Sherri A; Middleton, Dannie C; Falk, Henry

    2002-01-01

    People with asthma who live near or downwind from a source of toxic emissions commonly express concerns about the possible impact of hazardous air pollution on their health, especially when these emissions are visible or odorous. Citizens frequently turn to their local and state health departments for answers, but health departments face many challenges in addressing these concerns. These challenges include a lack of asthma statistics at the local level, limited exposure information, and a paucity of scientific knowledge about the contributions of hazardous air pollutants to asthma induction or exacerbation. Health agencies are creatively developing methods to address these challenges while working toward improving asthma surveillance data at the state and local levels. Recent community health investigations suggest that hazardous air pollutants that are occupational asthmagens or associated with odors may deserve more attention. In seeking to address community concerns about hazardous air pollution and asthma, community health investigations may also help to fill gaps in our scientific knowledge and identify areas for further research or environmental intervention. The solutions to community problems associated with environmental contamination and asthma, however, require sustained, coordinated efforts by public and private groups and citizens. Public health agencies can make a unique contribution to this effort, but additional resources and support will be required to develop information systems and epidemiologic capacity at the state and local levels. PMID:12194887

  14. Factors affecting xylene-contaminated air removal by the ornamental plant Zamioculcas zamiifolia.

    PubMed

    Sriprapat, Wararat; Boraphech, Phattara; Thiravetyan, Paitip

    2014-02-01

    Fifteen plant species-Alternanthera bettzickiana, Drimiopsis botryoides, Aloe vera, Chlorophytum comosum, Aglaonema commutatum, Cordyline fruticosa, Philodendron martianum, Sansevieria hyacinthoides, Aglaonema rotundum, Fittonia albivenis, Muehlenbeckia platyclada, Tradescantia spathacea, Guzmania lingulata, Zamioculcas zamiifolia, and Cyperus alternifolius-were evaluated for the removal efficiency of xylene from contaminated air. Among the test plants, Z. zamiifolia showed the highest xylene removal efficiency. Xylene was toxic to Z. zamiifolia with an LC50 of 3,464 ppm. Higher concentrations of xylene exhibited damage symptoms, including leaf tips turning yellow, holonecrosis, and hydrosis. TEM images showed that a low concentration of xylene vapors caused minor changes in the chloroplast, while a high concentration caused swollen chloroplasts and damage. The effect of photosynthetic types on xylene removal efficiency suggests that a mixture of Z. zamiifolia, S. hyacinthoides, and A. commutatum which represent facultative CAM, CAM, and C3 plants, is the most suitable system for xylene removal. Therefore, for maximum improvement in removing xylene volatile compounds under various conditions, multiple species are needed. The effect of a plant's total leaf area on xylene removal indicates that at lower concentrations of xylene, a small leaf area might be as efficient as a large leaf area.

  15. Factors affecting xylene-contaminated air removal by the ornamental plant Zamioculcas zamiifolia.

    PubMed

    Sriprapat, Wararat; Boraphech, Phattara; Thiravetyan, Paitip

    2014-02-01

    Fifteen plant species-Alternanthera bettzickiana, Drimiopsis botryoides, Aloe vera, Chlorophytum comosum, Aglaonema commutatum, Cordyline fruticosa, Philodendron martianum, Sansevieria hyacinthoides, Aglaonema rotundum, Fittonia albivenis, Muehlenbeckia platyclada, Tradescantia spathacea, Guzmania lingulata, Zamioculcas zamiifolia, and Cyperus alternifolius-were evaluated for the removal efficiency of xylene from contaminated air. Among the test plants, Z. zamiifolia showed the highest xylene removal efficiency. Xylene was toxic to Z. zamiifolia with an LC50 of 3,464 ppm. Higher concentrations of xylene exhibited damage symptoms, including leaf tips turning yellow, holonecrosis, and hydrosis. TEM images showed that a low concentration of xylene vapors caused minor changes in the chloroplast, while a high concentration caused swollen chloroplasts and damage. The effect of photosynthetic types on xylene removal efficiency suggests that a mixture of Z. zamiifolia, S. hyacinthoides, and A. commutatum which represent facultative CAM, CAM, and C3 plants, is the most suitable system for xylene removal. Therefore, for maximum improvement in removing xylene volatile compounds under various conditions, multiple species are needed. The effect of a plant's total leaf area on xylene removal indicates that at lower concentrations of xylene, a small leaf area might be as efficient as a large leaf area. PMID:24091527

  16. Validation of a novel air toxic risk model with air monitoring.

    PubMed

    Pratt, Gregory C; Dymond, Mary; Ellickson, Kristie; Thé, Jesse

    2012-01-01

    Three modeling systems were used to estimate human health risks from air pollution: two versions of MNRiskS (for Minnesota Risk Screening), and the USEPA National Air Toxics Assessment (NATA). MNRiskS is a unique cumulative risk modeling system used to assess risks from multiple air toxics, sources, and pathways on a local to a state-wide scale. In addition, ambient outdoor air monitoring data were available for estimation of risks and comparison with the modeled estimates of air concentrations. Highest air concentrations and estimated risks were generally found in the Minneapolis-St. Paul metropolitan area and lowest risks in undeveloped rural areas. Emissions from mobile and area (nonpoint) sources created greater estimated risks than emissions from point sources. Highest cancer risks were via ingestion pathway exposures to dioxins and related compounds. Diesel particles, acrolein, and formaldehyde created the highest estimated inhalation health impacts. Model-estimated air concentrations were generally highest for NATA and lowest for the AERMOD version of MNRiskS. This validation study showed reasonable agreement between available measurements and model predictions, although results varied among pollutants, and predictions were often lower than measurements. The results increased confidence in identifying pollutants, pathways, geographic areas, sources, and receptors of potential concern, and thus provide a basis for informing pollution reduction strategies and focusing efforts on specific pollutants (diesel particles, acrolein, and formaldehyde), geographic areas (urban centers), and source categories (nonpoint sources). The results heighten concerns about risks from food chain exposures to dioxins and PAHs. Risk estimates were sensitive to variations in methodologies for treating emissions, dispersion, deposition, exposure, and toxicity.

  17. Landfill Leachate Toxicity Removal in Combined Treatment with Municipal Wastewater

    PubMed Central

    Kalka, J.

    2012-01-01

    Combined treatment of landfill leachate and municipal wastewater was performed in order to investigate the changes of leachate toxicity during biological treatment. Three laboratory A2O lab-scale reactors were operating under the same parameters (Q-8.5–10 L/d; HRT-1.4–1.6 d; MLSS 1.6–2.5 g/L) except for the influent characteristic and load. The influent of reactor I consisted of municipal wastewater amended with leachate from postclosure landfill; influent of reactor II consisted of leachate collected from transient landfill and municipal wastewater; reactor III served as a control and its influent consisted of municipal wastewater only. Toxicity of raw and treated wastewater was determinted by four acute toxicity tests with Daphnia magna, Thamnocephalus platyurus, Vibrio fischeri, and Raphidocelis subcapitata. Landfill leachate increased initial toxicity of wastewater. During biological treatment, significant decline of acute toxicity was observed, but still mixture of leachate and wastewater was harmful to all tested organisms. PMID:22623882

  18. Phytoremediation: A novel strategy for the removal of toxic metals from the environment using plants

    SciTech Connect

    Salt, D.E.; Blaylock, M.; Kumar, N. P.B.A.

    1995-05-01

    Toxic metal pollution of waters and soils is a major environmental problem, and most conventional remediation approaches do not provide acceptable solutions. The use of specially selected and engineered metal-accumulating plants for environmental clean-up is an emerging technology called phytoremediation. Three subsets of this technology are applicable to toxic metal remediation: (1) Phytoextraction: the use of metal-accumulating plants to remove toxic metals from soil; (2) Rhizofiltration: the use of plant roots to remove toxic metals from polluted waters; and (3) Phytostabilization: the use of plants to eliminate the bioavailability of toxic metals in soils. Biological mechanisms of toxic metal uptake, translocation and resistance as well as strategies for improving phytoremediation are also discussed. 83 refs., 4 figs., 1 tab.

  19. Toxic Gas Removal by Dielectric Discharge with Corona Effect

    SciTech Connect

    Moreno, H.; Pacheco, M.; Mercado, A.; Cruz, A.; Pacheco, J.; Yousfi, M.; Eichwald, O.; Benhenni, M.

    2006-12-04

    In this work, a theoretical and experimental study on SO2 and NOx removal by non-thermal plasma technology, more specifically a dielectric barrier (DBD) discharge combined with the Corona effect, is presented. Results obtained from a theoretical study describe the chemical kinetic model of SO2 and NOx removal processes; the effect of OH radicals in removal of both gases is noteworthy. Experimental results of de-SO2 process are reported. Also, optical emission spectroscopy study was applied on some atomic helium lines to obtain temperature of electrons in the non-thermal plasma.

  20. Toxic Gas Removal by Dielectric Discharge with Corona Effect

    NASA Astrophysics Data System (ADS)

    Moreno, H.; Pacheco, M.; Pacheco, J.; Mercado, A.; Cruz, A.; Yousfi, M.; Eichwald, O.; Benhenni, M.

    2006-12-01

    In this work, a theoretical and experimental study on SO2 and NOx removal by non-thermal plasma technology, more specifically a dielectric barrier (DBD) discharge combined with the Corona effect, is presented. Results obtained from a theoretical study describe the chemical kinetic model of SO2 and NOx removal processes; the effect of OH radicals in removal of both gases is noteworthy. Experimental results of de-SO2 process are reported. Also, optical emission spectroscopy study was applied on some atomic helium lines to obtain temperature of electrons in the non-thermal plasma.

  1. Removal of gasoline volatile organic compounds via air biofiltration

    SciTech Connect

    Miller, R.S.; Saberiyan, A.G.; Esler, C.T.; DeSantis, P.; Andrilenas, J.S.

    1995-12-31

    Volatile organic compounds (VOCs) generated by vapor extraction and air-stripping systems can be biologically treated in an air biofiltration unit. An air biofilter consists of one or more beds of packing material inoculated with heterotrophic microorganisms capable of degrading the organic contaminant of concern. Waste gases and oxygen are passed through the inoculated packing material, where the microorganisms will degrade the contaminant and release CO{sub 2} + H{sub 2}O. Based on data obtained from a treatability study, a full-scale unit was designed and constructed to be used for treating gasoline vapors generated by a vapor-extraction and groundwater-treatment system at a site in California. The unit is composed of two cylindrical reactors with a total packing volume of 3 m{sup 3}. Both reactors are packed with sphagnum moss and inoculated with hydrocarbon-degrading microorganisms of Pseudomonas and Arthrobacter spp. The two reactors are connected in series for air-flow passage. Parallel lines are used for injection of water, nutrients, and buffer to each reactor. Data collected during the startup program have demonstrated an air biofiltration unit with high organic-vapor-removal efficiency.

  2. 3 CFR - Flexible Implementation of the Mercury and Air Toxics Standards Rule

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 3 The President 1 2012-01-01 2012-01-01 false Flexible Implementation of the Mercury and Air... Flexible Implementation of the Mercury and Air Toxics Standards Rule Memorandum for the Administrator of... the final Mercury and Air Toxics Standards rule for power plants (the “MATS Rule”) represents a...

  3. Optimizing electric utility air toxics compliance with other titles of the Clean Air Act

    SciTech Connect

    Loeb, A.P.; South, D.W.

    1993-12-31

    This paper provides an overview of regulatory issues under Title III of the Clean Air Act Amendments that could affect electric utilities. Title III contains provisions relating to hazardous air pollutants (HAPs) and provides special treatment for electric utilities. Generally, this discussion documents that if utility toxic emissions are regulated, one of the chief difficulties confronting utilities will be the lack of coordination between Title III and other titles of the Act. The paper concludes that if the US Environmental Protection Agency (EPA) determines that regulation of utility HAPs is warranted under Title III, savings can be realized from flexible compliance treatment.

  4. Ammonia removal from landfill leachate by air stripping and absorption.

    PubMed

    Ferraz, Fernanda M; Povinelli, Jurandyr; Vieira, Eny Maria

    2013-01-01

    An old landfill leachate was pre-treated in a pilot-scale aerated packed tower operated in batch mode for total ammoniacal nitrogen (TAN) removal. The stripped ammonia was recovered with a 0.4 mol L(-1) H2SO4 solution, deionized water and tap water. Ca(OH)2 (95% purity) or commercial hydrated lime was added to the raw leachate to adjust its pH to 11, causing removal of colour (82%) and heavy metals (70-90% for Zn, Fe and Mn). The 0.4 molL(-1) H2SO4 solution was able to neutralize 80% of the stripped ammonia removed from 12 L of leachate. The effectiveness of the neutralization of ammonia with deionized water was 75%. Treating 100 L of leachate, the air stripping tower removed 88% of TAN after 72 h of aeration, and 87% of the stripped ammonia was recovered in two 31 L pilot-scale absorption units filled with 20 L of tap water.

  5. Ammonia removal from landfill leachate by air stripping and absorption.

    PubMed

    Ferraz, Fernanda M; Povinelli, Jurandyr; Vieira, Eny Maria

    2013-01-01

    An old landfill leachate was pre-treated in a pilot-scale aerated packed tower operated in batch mode for total ammoniacal nitrogen (TAN) removal. The stripped ammonia was recovered with a 0.4 mol L(-1) H2SO4 solution, deionized water and tap water. Ca(OH)2 (95% purity) or commercial hydrated lime was added to the raw leachate to adjust its pH to 11, causing removal of colour (82%) and heavy metals (70-90% for Zn, Fe and Mn). The 0.4 molL(-1) H2SO4 solution was able to neutralize 80% of the stripped ammonia removed from 12 L of leachate. The effectiveness of the neutralization of ammonia with deionized water was 75%. Treating 100 L of leachate, the air stripping tower removed 88% of TAN after 72 h of aeration, and 87% of the stripped ammonia was recovered in two 31 L pilot-scale absorption units filled with 20 L of tap water. PMID:24350487

  6. Air toxics provisions of the Clean Air Act: Potential impacts on energy

    SciTech Connect

    Hootman, H.A.; Vernet, J.E.

    1991-11-01

    This report provides an overview of the provisions of the Clean Air Act and its Amendments of 1990 that identify hazardous air pollutant (HAP) emissions and addresses their regulation by the US Environmental Protection Agency (EPA). It defines the major energy sector sources of these HAPs that would be affected by the regulations. Attention is focused on regulations that would cover coke oven emissions; chromium emission from industrial cooling towers and the electroplating process; HAP emissions from tank vessels, asbestos-related activities, organic solvent use, and ethylene oxide sterilization; and emissions of air toxics from municipal waste combustors. The possible implications of Title III regulations for the coal, natural gas, petroleum, uranium, and electric utility industries are examined. The report discusses five major databases of HAP emissions: (1) TRI (EPA`s Toxic Release Inventory); (2) PISCES (Power Plant Integrated Systems: Chemical Emissions Studies developed by the Electric Power Research Institute); (3) 1985 Emissions Inventory on volatile organic compounds (used for the National Acid Precipitation Assessment Program); (4) Particulate Matter Species Manual (EPA); and (5) Toxics Emission Inventory (National Aeronautics and Space Administration). It also offers information on emission control technologies for municipal waste combustors.

  7. Air toxics provisions of the Clean Air Act: Potential impacts on energy

    SciTech Connect

    Hootman, H.A.; Vernet, J.E.

    1991-11-01

    This report provides an overview of the provisions of the Clean Air Act and its Amendments of 1990 that identify hazardous air pollutant (HAP) emissions and addresses their regulation by the US Environmental Protection Agency (EPA). It defines the major energy sector sources of these HAPs that would be affected by the regulations. Attention is focused on regulations that would cover coke oven emissions; chromium emission from industrial cooling towers and the electroplating process; HAP emissions from tank vessels, asbestos-related activities, organic solvent use, and ethylene oxide sterilization; and emissions of air toxics from municipal waste combustors. The possible implications of Title III regulations for the coal, natural gas, petroleum, uranium, and electric utility industries are examined. The report discusses five major databases of HAP emissions: (1) TRI (EPA's Toxic Release Inventory); (2) PISCES (Power Plant Integrated Systems: Chemical Emissions Studies developed by the Electric Power Research Institute); (3) 1985 Emissions Inventory on volatile organic compounds (used for the National Acid Precipitation Assessment Program); (4) Particulate Matter Species Manual (EPA); and (5) Toxics Emission Inventory (National Aeronautics and Space Administration). It also offers information on emission control technologies for municipal waste combustors.

  8. A new method for the removal of toxic metal ions from acid-sensitive biomaterial

    SciTech Connect

    Seki, Hideshi; Suzuki, Akira

    1997-06-01

    A new method (competitive adsorption method) for the removal of toxic heavy metals from acid-sensitive biomaterials was proposed and it was applied to the removal of cadmium from the midgut gland (MG) of scallop, Patinopecten yessoensis. Insolubilized humic acid, which has been developed in the laboratory, was used as a competitive adsorbent. A metal-complexation model was used to determine the adsorption characteristics of cadmium onto MG. Furthermore, the model was applied to the competitive adsorption system. The results showed that the competitive adsorption method enabled the simultaneous removal of toxic cadmium from both liquid and MG phase under mild acidic condition (pH 5).

  9. Microcystins in potable surface waters: toxic effects and removal strategies.

    PubMed

    Roegner, Amber F; Brena, Beatriz; González-Sapienza, Gualberto; Puschner, Birgit

    2014-05-01

    In freshwater, harmful cyanobacterial blooms threaten to increase with global climate change and eutrophication of surface waters. In addition to the burden and necessity of removal of algal material during water treatment processes, bloom-forming cyanobacteria can produce a class of remarkably stable toxins, microcystins, difficult to remove from drinking water sources. A number of animal intoxications over the past 20 years have served as sentinels for widespread risk presented by microcystins. Cyanobacterial blooms have the potential to threaten severely both public health and the regional economy of affected communities, particularly those with limited infrastructure or resources. Our main objectives were to assess whether existing water treatment infrastructure provides sufficient protection against microcystin exposure, identify available options feasible to implement in resource-limited communities in bloom scenarios and to identify strategies for improved solutions. Finally, interventions at the watershed level aimed at bloom prevention and risk reduction for entry into potable water sources were outlined. We evaluated primary studies, reviews and reports for treatment options for microcystins in surface waters, potable water sources and treatment plants. Because of the difficulty of removal of microcystins, prevention is ideal; once in the public water supply, the coarse removal of cyanobacterial cells combined with secondary carbon filtration of dissolved toxins currently provides the greatest potential for protection of public health. Options for point of use filtration must be optimized to provide affordable and adequate protection for affected communities. PMID:24038121

  10. Urban land use, air toxics and public health: Assessing hazardous exposures at the neighborhood scale

    SciTech Connect

    Corburn, Jason . E-mail: jtc2105@columbia.edu

    2007-03-15

    Land use data are increasingly understood as important indicators of potential environmental health risk in urban areas where micro-scale or neighborhood level hazard exposure data are not routinely collected. This paper aims to offer a method for estimating the distribution of air toxics in urban neighborhoods using land use information because actual air monitoring data rarely exist at this scale. Using Geographic Information System spatial modeling tools, we estimate air toxics concentrations across neighborhoods in New York City and statistically compare our model with the US Environmental Protection Agency's National Air Toxic Assessment and air monitoring data across three NYC neighborhoods. We conclude that land use data can act as a good proxy for estimating neighborhood scale air toxics, particularly in the absence of monitoring data. In addition, the paper suggests that land use data can expand the reach of environmental impact assessments that routinely exclude analyses of potential exposures to urban air toxics at the neighborhood scale.

  11. Wire-Mesh-Based Sorber for Removing Contaminants from Air

    NASA Technical Reports Server (NTRS)

    Perry, Jay; Roychoudhury, Subir; Walsh, Dennis

    2006-01-01

    A paper discusses an experimental regenerable sorber for removing CO2 and trace components principally, volatile organic compounds, halocarbons, and NH3 from spacecraft cabin air. This regenerable sorber is a prototype of what is intended to be a lightweight alternative to activated-carbon and zeolite-pellet sorbent beds now in use. The regenerable sorber consists mainly of an assembly of commercially available meshes that have been coated with a specially-formulated washcoat containing zeolites. The zeolites act as the sorbents while the meshes support the zeolite-containing washcoat in a configuration that affords highly effective surface area for exposing the sorbents to flowing air. The meshes also define flow paths characterized by short channel lengths to prevent excessive buildup of flow boundary layers. Flow boundary layer resistance is undesired because it can impede mass and heat transfer. The total weight and volume comparison versus the atmosphere revitalization equipment used onboard the International Space Station for CO2 and trace-component removal will depend upon the design details of the final embodiment. However, the integrated mesh-based CO2 and trace-contaminant removal system is expected to provide overall weight and volume savings by eliminating most of the trace-contaminant control equipment presently used in parallel processing schemes traditionally used for spacecraft. The mesh-based sorbent media enables integrating the two processes within a compact package. For the purpose of regeneration, the sorber can be heated by passing electric currents through the metallic meshes combined with exposure to space vacuum. The minimal thermal mass of the meshes offers the potential for reduced regeneration-power requirements and cycle time required for regeneration compared to regenerable sorption processes now in use.

  12. Advanced combustor design concept to control NOx and air toxics

    SciTech Connect

    Eddings, E.G.; Pershing, D.W.; Molina, A.; Sarofim, A.F.; Spinti, J.P.; Veranth, J.

    1999-03-29

    Direct coal combustion needs to be a primary energy source for the electric utility industry and for heavy manufacturing during the next several decades because of the availability and economic advantage of coal relative to other fuels and because of the time required to produce major market penetration in the energy field. However, the major obstacle to coal utilization is a set of ever-tightening environmental regulations at both the federal and local level. It is, therefore, critical that fundamental research be conducted to support the development of low-emission, high-efficiency pulverized coal power systems. The objective of this program was to develop fundamental understanding regarding the impact of fuel and combustion changes on NOx formation, carbon burnout and air toxic emissions from pulverized coal (pc) combustion. During pc combustion, nitrogen in the coal can be oxidized to form nitrogen oxides (NO{sub x}). The 1990 Clean Air Act Amendments established much stricter NO{sub x} emissions limits for new and existing coal-fired plants, so there has been renewed interest in the processes by which NO{sub x} forms in pc flames. One of the least understood aspects of NO{sub x} formation from pc combustion is the process by which char-N (nitrogen remaining in the char after devolatilization) forms either NO{sub x} or N{sub 2}, and the development of a fundamental understanding of this process was a major focus of this research. The overall objective of this program was to improve the ability of combustion system designers and boiler manufacturers to build high efficiency, low emission pulverized coal systems by improving the design tools available to the industry. The specific program goals were to: Use laboratory experiments and modeling to develop fundamental understanding for a new submodel for char nitrogen oxidation (a critical piece usually neglected in most NOx models.); Use existing bench scale facilities to investigate alternative schemes to

  13. Air quality modeling of selected aromatic and non-aromatic air toxics in the Houston urban and industrial airshed

    NASA Astrophysics Data System (ADS)

    Coarfa, Violeta Florentina

    2007-12-01

    Air toxics, also called hazardous air pollutants (HAPs), pose a serious threat to human health and the environment. Their study is important in the Houston area, where point sources, mostly located along the Ship Channel, mobile and area sources contribute to large emissions of such toxic pollutants. Previous studies carried out in this area found dangerous levels of different HAPs in the atmosphere. This thesis presents several studies that were performed for the aromatic and non-aromatic air toxics in the HGA. For these studies we developed several tools: (1) a refined chemical mechanism, which explicitly represents 18 aromatic air toxics that were lumped under two model species by the previous version, based on their reactivity with the hydroxyl radical; (2) an engineering version of an existing air toxics photochemical model that enables us to perform much faster long-term simulations compared to the original model, that leads to a 8--9 times improvement in the running time across different computing platforms; (3) a combined emission inventory based on the available emission databases. Using the developed tools, we quantified the mobile source impact on a few selected air toxics, and analyzed the temporal and spatial variation of selected aromatic and non-aromatic air toxics in a few regions within the Houston area; these regions were characterized by different emissions and environmental conditions.

  14. Microbial removal of toxic metals from a heavily polluted soil

    NASA Astrophysics Data System (ADS)

    Nicolova, Marina; Spasova, Irena; Georgiev, Plamen; Groudev, Stoyan

    2015-04-01

    Samples of a leached cinnamonic forest soil heavily polluted with uranium and some toxic heavy metals (mainly copper, zinc and cadmium) were subjected to cleaning by means of bioleaching with acidophilic chemolithotrophic bacteria. The treatment was carried out in a green house in which several plots containing 150 kg of soil each were constructed. The effect of some essential environmental factors such as pH, humidity, temperature and contents of nutrients on the cleaning process was studied. It was found that under optimal conditions the content of pollutants were decreased below the relevant permissible levels within a period of 170 days. The soil cleaned in this way was characterized by a much higher production of biomass of different plants (alfalfa, clover, red fescue, vetch) than the untreated polluted soil.

  15. 78 FR 34966 - Approval and Promulgation of Air Quality Implementation Plans; Wisconsin; Removal of Gasoline...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-11

    ..., including sulfur dioxide and nitrogen dioxide. EPA has no reason to believe that the removal of the Stage II... AGENCY 40 CFR Part 52 Approval and Promulgation of Air Quality Implementation Plans; Wisconsin; Removal... section 110(l) of the Clean Air Act (CAA) that addresses emissions impacts associated with the removal...

  16. EMISSIONS OF ORGANIC AIR TOXICS FROM OPEN BURNING: A COMPREHENSIVE REVIEW

    EPA Science Inventory

    A detailed literature search was performed to collect and collate available data reporting emissions of organic air toxics from open burning sources. Availability of data varied according to the source and the class of air toxics of interest, and there were several sources for wh...

  17. Analysis of mobile source air toxics (MSATs)–Near-Road VOC and carbonyl concentrations

    EPA Science Inventory

    Exposures to mobile source air toxics (MSATs) have been associated with numerous adverse health effects. While thousands of air toxic compounds are emitted from mobile sources, a subset of compounds are considered high priority due to their significant contribution to cancer and...

  18. Analysis of Mobile Source Air Toxics (MSATS)–Near-Road VOC and CarbonylConcentrations

    EPA Science Inventory

    This presentation examines data from a year-long study of measured near-road mobile source air toxic (MSAT) concentrations and compares these data with modeled 2005 National Air Toxic Assessment (NATA) results. Field study measurements were collected during a field campaign in ...

  19. 77 FR 30274 - The Commission's Role Regarding the Environmental Protection Agency's Mercury and Air Toxics...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-22

    .../pkg/FR-2012-02-16/pdf/2012-806.pdf . I. Introduction 2. On December 21, 2011, the EPA released the... Mercury and Air Toxics Standards; Policy Statement on the Commission's Role Regarding the Environmental Protection Agency's Mercury and Air Toxics Standards Before Commissioners: Jon Wellinghoff, Chairman;...

  20. 76 FR 80727 - Flexible Implementation of the Mercury and Air Toxics Standards Rule

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-27

    ... 21, 2011 [FR Doc. 2011-33337 Filed 12-23-11; 8:45 am] Billing code 6560-50-P ... Documents#0;#0; ] Memorandum of December 21, 2011 Flexible Implementation of the Mercury and Air Toxics... the Environmental Protection Agency (EPA), of the final Mercury and Air Toxics Standards rule...

  1. Uncertainty for data with non-detects: Air toxic emissions from combustion

    SciTech Connect

    Zhao, Y.C.; Frey, H.C.

    2006-12-15

    Air toxic emission factor datasets often contain one or more points below a single or multiple detection limits and such datasets are referred to as 'censored.' Conventional methods used to deal with censored datasets include removing non-detects, replacing the censored points with zero, half of the detection limit, or the detection limit. However, the estimated means of the censored dataset by conventional methods are usually biased. Maximum likelihood estimation (MLE) and bootstrap simulation have been demonstrated as a statistically robust method to quantify variability and uncertainty of censored datasets and can provide asymptotically unbiased mean estimates. The MLE/bootstrap method is applied to 16 cases of censored air toxic emission factors, including benzene, formaldehyde, benzo(a)pyrene, mercury, arsenic, cadmium, total chromium, chromium VI and lead from coal, fuel oil, and/or wood waste external combustion sources. The proportion of censored values in the emission factor data ranges from 4 to 80%. Key factors that influence the estimated uncertainty in the mean of censored data are sample size and inter-unit variability. The largest range of uncertainty in the mean was obtained for the external coal combustion benzene emission factor, with 95 confidence interval of the mean equal to minus 93 to plus 411%.

  2. Biological removal of carbon disulfide from waste air streams

    SciTech Connect

    Hugler, W.; Acosta, C.; Revah, S.

    1999-09-30

    A pilot-scale biological control system for the treatment of 3,400 m{sup 3} h{sup {minus}1} of a gaseous stream containing up to 7.8 g CS{sub 2} m{sup {minus}3} and trace amounts of hydrogen sulfide (H{sub 2}S) was installed in a cellulose sponge manufacturing facility. The objective was to demonstrate the capability of the process to attain sustained removal efficiencies of 90% for CS{sub 2} and 99% for H{sub 2}S. The system consisted of two sequential biotrickling reactors, which had been previously inoculated with an adapted microbial consortium. During the pilot test, stable removal efficiency and elimination capacity of +90% and 220g CS{sub 2} m{sup {minus}3} h{sup {minus}1}, respectively, were attained with an empty bed residence time (EBTR) of 33 seconds for a period of several weeks. Efficiencies greater than 99% were always obtained for H{sub 2}S. Based on the results, the system was determined to be an effective process to remediate waste air streams containing reduced sulfur compounds generated at cellulose sponge facilities.

  3. Immobilized materials for removal of toxic metal ions from surface/groundwaters and aqueous waste streams.

    PubMed

    Zawierucha, Iwona; Kozlowski, Cezary; Malina, Grzegorz

    2016-04-01

    Heavy metals from industrial processes are of special concern because they produce chronic poisoning in the aquatic environment. More strict environmental regulations on the discharge of toxic metals require the development of various technologies for their removal from polluted streams (i.e. industrial wastewater, mine waters, landfill leachate, and groundwater). The separation of toxic metal ions using immobilized materials (novel sorbents and membranes with doped ligands), due to their high selectivity and removal efficiency, increased stability, and low energy requirements, is promising for improving the environmental quality. This critical review is aimed at studying immobilized materials as potential remediation agents for the elimination of numerous toxic metal (e.g. Pb, Cd, Hg, and As) ions from polluted streams. This study covers the general characteristics of immobilized materials and separation processes, understanding of the metal ion removal mechanisms, a review of the application of immobilized materials for the removal of toxic metal ions, as well as the impacts of various parameters on the removal efficiency. In addition, emerging trends and opportunities in the field of remediation technologies using these materials are addressed.

  4. HAPs-Rx: Precombustion Removal of Hazardous Air Pollutant Precursors

    SciTech Connect

    David J. Akers; Clifford E. Raleigh

    1998-03-16

    CQ Inc. and its project team members--Howard University, PrepTech Inc., Fossil Fuel Sciences, the United States Geological Survey (USGS), and industry advisors--are applying mature coal cleaning and scientific principles to the new purpose of removing potentially hazardous air pollutants from coal. The team uniquely combines mineral processing, chemical engineering, and geochemical expertise. This project meets more than 11 goals of the U.S. Department of Energy (DOE), the National Energy Strategy, and the 1993 Climate Change Action Plan. During this project: (1) Equations were developed to predict the concentration of trace elements in as-mined and cleaned coals. These equations, which address both conventional and advanced cleaning processes, can be used to increase the removal of hazardous air pollutant precursors (HAPs) by existing cleaning plants and to improve the design of new cleaning plants. (2) A promising chemical method of removing mercury and other HAPs was developed. At bench-scale, mercury reductions of over 50 percent were achieved on coal that had already been cleaned by froth flotation. The processing cost of this technology is projected to be less than $3.00 per ton ($3.30 per tonne). (3) Projections were made of the average trace element concentration in cleaning plant solid waste streams from individual states. Average concentrations were found to be highly variable. (4) A significantly improved understanding of how trace elements occur in coal was gained, primarily through work at the USGS during the first systematic development of semiquantitative data for mode of occurrence. In addition, significant improvement was made in the laboratory protocol for mode of occurrence determination. (5) Team members developed a high-quality trace element washability database. For example, the poorest mass balance closure for the uncrushed size and washability data for mercury on all four coals is 8.44 percent and the best is 0.46 percent. This indicates an

  5. Effect of pyrolysis temperature and air flow on toxicity of gases from a polycarbonate polymer

    NASA Technical Reports Server (NTRS)

    Hilado, C. J.; Brick, V. E.; Brauer, D. P.

    1978-01-01

    A polycarbonate polymer was evaluated for toxicity of pyrolysis gases generated at various temperatures without forced air flow and with 1 L/min air flow, using the toxicity screening test method developed at the University of San Francisco. Time to various animal responses decreased with increasing pyrolysis temperature over the range from 500 C to 800 C. There appeared to be no significant toxic effects at 400 C and lower temperatures.

  6. Removal and recovery of toxic metal ions from aqueous waste sites using polymer pendant ligands

    SciTech Connect

    Fish, D.

    1996-10-01

    The purpose of this project is to investigate the use of polymer pendant ligand technology to remove and recover toxic metal ions from DOE aqueous waste sites. Polymer pendant lgiands are organic ligands, anchored to crosslinked, modified divinylbenzene-polystyrene beads, that can selectively complex metal ions. The metal ion removal step usually occurs through a complexation or ion exchange phenomena, thus recovery of the metal ions and reuse of the beads is readily accomplished.

  7. Lifetimes and fates of toxic air contaminants in California's atmosphere, June 1993. Final report

    SciTech Connect

    Atkinson, R.; Arey, J.

    1993-06-01

    The report presents information concerning the nature and rate of removal of toxic air pollutants (TAPs) from the atmosphere and any products formed; it also addresses the formation of possible TAPs in the atmosphere. It contains a comprehensive review of the atmospheric chemistry of di(2-ethylhexyl)phthalate, N-nitrosomorpholine, and dialkylnitrosamines. It also outlines the atmospheric lifetimes of 23 possible TAPs, including: hexachlorobenzene, 1,4-dichlorobenzene, dimethyl sulfate, propylene oxide, chlorobenzene, 2,4,6-trichlorophenol, benxyl chloride, acrylonitrile, toluene diisocyanates, and 1,4-dioxane. It also reviews possible atmospheric formation of TAPs. Acrolein, formaldehyde, acetaldehyde, and PAHs are shown to be present in the atmosphere largely due to atmospheric reactions. Another section describes an investigation of the mutagenicity of products of simulated atmospheric reactions of gasoline and terpenes (emitted from vegetation). These may not be major sources of ambient mutagenicity in California.

  8. Catalytic process for removing toxic gases from gas streams

    SciTech Connect

    Baglio, J.A.; Gaudet, G.G.; Palilla, F.C.

    1983-02-22

    A multi-stage process for reducing the content of sulfurcontaining gases-notably hydrogen sulfide, sulfur dioxide, carbonyl sulfide and carbon disulfide-in waste gas streams is provided. In the first stage, the gas stream is passed through a reaction zone at a temperature between about 150 and 350/sup 0/C in the presence of a pretreated novel catalyst of the formula xLn/sub 2/O/sub 3/ in which Ln is yttrium or a rare earth element and T is cobalt, iron or nickel, and each of x and y is independently a number from 0 to 3, said catalyst being substantially non-crystalline and having a surface area of from about 10 m/sup 2//g to about 40 m/sup 2//g. The preferred catalyst is one in which Ln is lanthanum, T is cobalt, and x and y range from 1 to 3, including non-integers. The first stage yields a product stream having a reduced content of sulfur-containing gases, including specifically, substantial reduction of carbonyl sulfide and virtual elimination of carbon disulfide. An intermediate stage is a claus reaction, which may take place in one or more reaction zones, at temperatures less than about 130/sup 0/ C, in the presence of known catalysts such as bauxite, alumina or cobalt molybdates. The final stage is the air oxidation of hydrogen sulfide at a temperature between about 150 and 300/sup 0/ C in the presence of a catalyst usable in first stage.

  9. 1991 EPA/AWMA international symposium on measurement of toxic and related air pollutants

    SciTech Connect

    Gay, B.W. Jr.

    1991-01-01

    The purpose of this symposium was to provide a forum for exchange of information on the measurement of toxic and related air pollutants. The conference included presentations on the following: ozone precursors; atmospheric chemistry and fate of toxic pollutants; measurement of particulates and acidic aerosols; cloud water chemistry; asbestos exposure assessment; Staten Island/NJ Urban Air Toxics Assessment Project; personal exposure monitors; mobile sources emissions characterization; VOC monitoring for Clean Air Act Amendment requirement; product emission measurement in test chambers; USA/USSR joint air pollution study; VOC monitoring techniques; measurement of VOCs; measurement of polar volatile organics; exposure assessment; remote sensing for emissions monitoring; measurement methods development; measurement of hazardous waste emissions; chemometrics and environmental data analysis; source monitoring; air pollution dispersion modeling; measurement and data analysis of indoor toxic air contaminants; and environmental quality assurance. Two hundred seventeen papers have been processed separately for inclusion in the appropriate data bases.

  10. Concentrations of air toxics in motor vehicle-dominated environments.

    PubMed

    Fujita, Eric M; Campbell, David E; Zielinska, Barbara; Arnott, William P; Chow, Judith C

    2011-02-01

    We at the Desert Research Institute (DRI*) measured volatile organic compounds (VOCs), including several mobile-source air toxics (MSATs), particulate matter with a mass mean aerodynamic diameter < or = 2.5 pm (PM2.5), black carbon (BC), nitrogen oxides (NOx), particulate matter (PM), and carbon monoxide (CO) on highways in Los Angeles County during summer and fall 2004, to characterize the diurnal and seasonal variations in measured concentrations related to volume and mix of traffic. Concentrations of on-road pollutants were then compared to corresponding measurements at fixed monitoring sites. The on-road concentrations of CO and MSATs were higher in the morning under stable atmospheric conditions and during periods of higher traffic volumes. In contrast, BC concentrations, measured as particulate light absorption, were higher on truck routes during the midday sampling periods despite more unstable atmospheric conditions. Compared to the measurements at the three near-road sites, the 1-hour averages of on-road BC concentrations were as much as an order of magnitude higher. The peak 1-minute average concentrations were two orders of magnitude higher for BC and were between two and six times higher for PM2.5 mass. The on-road concentrations of benzene, toluene, ethylbenzene, and xylenes (BTEX) during the summer were 3.5 +/- 0.7 and 1.2 +/- 0.6 times higher during morning and afternoon commuting periods, respectively, compared to annual average 24-hour concentrations measured at air toxic monitoring network sites. These ratios were higher during the fall, with smaller diurnal differences (4.8 +/- 0.7 and 3.9 +/- 0.6 for morning and afternoon commuting periods, respectively). Ratios similar to those for BTEX were obtained for 1,3-butadiene (BD) and styrene. On-road concentrations of formaldehyde and acetaldehyde were up to two times higher than at air toxics monitoring sites, with fall ratios slightly higher than summer ratios. Chemical mass balance (CMB) receptor

  11. Petroleum refinery secondary effluent polishing using freezing processes--toxicity and organic contaminant removal.

    PubMed

    Gao, W; Smith, D W; Habib, M

    2008-06-01

    A petroleum refinery secondary effluent was treated using two freezing techniques--spray freezing and unidirectional downward freezing (UDF). The freezing processes were effective to remove toxicity and total organic carbon (TOC)- and chemical oxygen demand (COD)-causing materials in the effluent. Agitation of the liquid during UDF significantly improved the impurity separation efficiency; 85 to 96% removal of TOC and COD was achieved without any pretreatment and freezing only 70% of the feed water. The treatment efficiency of the spray freezing was at the same level as that of UDF without mixing. The spray ice with longer storage time released more contaminants with early meltwater. The initial contaminant concentration of the feed water and the freezing temperatures (-10 degrees C and -25 degrees C) had no significant influence on the treatment efficiency. A small fluctuation in effluent TOC concentration caused a dramatic change in effluent toxicity (Microtox). The effective concentration (EC20) (Microtox) was effective in detecting effluent toxicity. PMID:18686927

  12. LARGE-SCALE PREDICTIONS OF MOBILE SOURCE CONTRIBUTIONS TO CONCENTRATIONS OF TOXIC AIR POLLUTANTS

    EPA Science Inventory

    This presentation shows concentrations and deposition of toxic air pollutants predicted by a 3-D air quality model, the Community Multi Scale Air Quality (CMAQ) modeling system. Contributions from both on-road and non-road mobile sources are analyzed.

  13. CMAQ MODELING FOR AIR TOXICS AT FINE SCALES: A PROTOTYPE STUDY

    EPA Science Inventory

    Toxic air pollutants (TAPs) or hazardous air pollutants (HAPs) exhibit considerable spatial and temporal variability across urban areas. Therefore, the ability of chemical transport models (CTMs), e.g. Community Multi-scale Air Quality (CMAQ), to reproduce the spatial and tempor...

  14. ULTRA HIGH EFFICIENCY ESP DEVELOPMENT FOR AIR TOXICS CONTROL

    SciTech Connect

    David K. Anderson

    1999-11-01

    Because more than 90 percent of U.S. coal-fired utility boilers are equipped with electrostatic precipitators (ESPs), retrofitable ESP technologies represent a logical approach towards achieving the Department of Energy's (DOE) goal of a major reduction in fine particulate and mercury emissions (air toxics) from coal based power systems. EPA's recent issuance of significantly tightened ambient air standards for particles smaller than 2.5 {micro}m (PM{sub 2.5}) creates a new urgency for developing cost-effective means to control fine particulate emissions. This challenge is compounded by the on-going switch in the utility industry to low-sulfur Powder River Basin (PRB) coals, that generate higher resistivity and difficult-to-collect fly ash. Particulate emissions can increase by a factor of ten when a utility switches to a low-sulfur coal. Numerous power plants are presently limited in operation by the inability of their ESPs to control opacity at high loads. In Phase I of this program, ABB investigated five technologies to improve the collection of fine particulate and trace metals in ESPs. These included: (1) flue-gas cooling, (2) flue-gas humidification, (3) pulsed energization, (4) wet ESP and precharger modules, and (5) sorbent injection for mercury control. Tests were conducted with an Eastern bituminous coal and a Powder River Basin sub-bituminous low-sulfur coal in an integrated pilot-scale combustor and ESP test facility. The impacts of the different retrofit technologies on ESP performance, individually and in combination, were evaluated indepth through advanced sampling and measurement techniques. In Phase II, the most promising concepts identified from Phase I testing, flue-gas cooling and humidification, pulsed energization, and sorbent injection at low flue-gas temperatures for mercury control, were integrated into a commercially oriented sub-scale system for field testing at Commonwealth Edison's Waukegan Unit No. 8. The main objective of the proposed

  15. Case study of municipal air pollution policies: Houston's Air Toxic Control Strategy under the White Administration, 2004-2009.

    PubMed

    Bruhl, Rebecca J; Linder, Stephen H; Sexton, Ken

    2013-05-01

    Local government has traditionally played only a minor role in regulating airborne toxic pollutants. However, from 2004 to 2009, the City of Houston implemented a novel, municipality-based air toxics reduction strategy to address what it considered unacceptable health risks and an insufficient regulatory response from state and federal agencies. The city's effort to exert local control over stationary sources of air toxics represents a unique opportunity to study the selection and performance of policy tools and to consider their ramifications for the design of future air pollution control strategies. The results of this case study demonstrate the potential for municipal government to use a combination of cooperative and confrontational policies to stimulate responses from private industry and state and federal regulators as part of a strategy to address local air quality problems.

  16. Old, the new, the states, the evolution of the regulation of air toxics. Master's thesis

    SciTech Connect

    Vecera, D.R.

    1993-02-14

    The activism associated with America in the 1960s spilled over into many areas, one of which was a new environmental movement. A product of that movement was the Clean Air Act passed in 1970. The new law included a selection aimed specifically at controlling emissions of hazardous or toxic air pollutants. However, over the next 20 years there was very little government regulation of air toxics, and this section of the Clean Air Act was considered to be a resounding failure. What went wrong. How did this lofty goal to protect human health and the environment end up on the back burner. The article will address the idealism that led to the Clean Air Act legislation, in particular the air toxics program, and explore the realities that scuttled those ideals when it came time to implement the law.

  17. Organic toxicants in air and precipitation samples from the Lake Michigan area

    SciTech Connect

    Harlin, K.S.; Sweet, C.W.; Gatz, D.F.

    1995-12-31

    Measurements of PCBs, organochlorine insecticides, PAHs, and atrazine were made in air and precipitation samples collected at regionally-representative locations near Lake Michigan from 1992-1995. The purpose of these measurements was to provide information needed to estimate the atmospheric deposition of organic toxicants to Lake Michigan. Twenty-four hour samples of airborne particles and vapor were collected at 12-day intervals on quartz fiber filters and XAD-2 resin vapor traps using modified high volume sampleers. Twenty-eight day precipitation samples were collected using wet-only samplers with stainless steel sampling surfaces and heated enclosure containing an XAD-2 resin adsorption column. Samples were Soxhlet extracted for 24 hours with hexane:acetone (1:1), and concentrated by rotary evaporation. Interferences were removed and the samples separated into analyte groups by silica gel chromatography. Four fractions were collected for GC-ECD and GC-Ion Trap MS analyses. Ten pesticides, 101 PCB congeners, 18 PAHs, and atrazine were measured in all samples. Quality assurance was maintained by including field duplicate samples, field blanks, alboratory matrix spikes, laboratory matrix blanks, and laboratory surrogate spikes in the sampling/analytical protocols. Preliminary results from urban and remote sites show geographical variations in the concentrations of some toxicants due to contributions from local sources. For all sites the total PCB levels are higher in the vapor phase than the particulate phase and show strong seasonal variations. Seasonal variations were also observed for several pesticides.

  18. MONITORING THE AIR FOR TOXIC AND GENOTOXIC COMPOUNDS

    EPA Science Inventory

    A time-integrated sampling system interfaced with a toxicity-based assay is reported for monitoring volatile toxic industrial chemicals (TICs). Semipermeable membrane devices (SPMDs) using dimethyl sulfoxide (DMSO) as the fill solvent accumulated each of 17 TICs from the vapor p...

  19. Biotreatment of produced water for removal of sulfides, organics, and toxicity

    SciTech Connect

    Rajganesh, B.; Selvaraj, P.T.; Manning, F.S.

    1995-12-31

    Water coproduced with petroleum may contain sulfides and organic constituents that give the water an aquatic toxicity preventing surface discharge. A simulated sour produced water and actual field samples of produced water were successfully biotreated with mixed cultures of Thiobacillus denitrificans and floc-forming heterotrophs. Complete removal of benzene, toluene, phenol, acetic acid, sulfides, and Microtox toxicity was achieved. These results indicate that a reactor system as simple in concept as a specialized activated sludge system can be used to treat produced water with these mixed contaminants, allowing surface discharge of the water for reuse.

  20. CAAA implementation & legislation combustion strategy, air toxics, etc.

    SciTech Connect

    Segal, S.

    1995-12-31

    Information is presented that deals with the status of the Clean Air Act implementation and legislation; the Republicans and the environment; the status of Superfund legislation in the Senate and the House; the Safe Drinking Water Act reauthorization bill; the Endangered Species Act; Section 112(g) of the Clean Air Act; the Comprehensive Regulatory Reform Act of 1995; and air Pollution.

  1. Biodiesel and Cold Temperature Effect on Speciated Mobile Source Air Toxics from Modern Diesel Trucks

    EPA Science Inventory

    Speciated volatile organic compounds (VOCs) with a particular focus on mobile source air toxics (MSATs) were measured in diesel exhaust from three heavy-duty trucks equipped with modern aftertreatment technologies. Emissions testing was conducted on a temperature controlled chass...

  2. Biodiesel and Cold Temperature Effects on Speciated Mobile Source Air Toxics from Modern Diesel Trucks

    EPA Science Inventory

    Speciated volatile organic compounds (VOCs) with a particular focus on mobile source air toxics (MSATs) were measured in diesel exhaust from three heavy-duty trucks equipped with modern aftertreatment technologies. Emissions testing was conducted on a temperature controlled chass...

  3. Promotion of Ni2+ removal by masking toxicity to sulfate-reducing bacteria: addition of citrate.

    PubMed

    Qian, Junwei; Zhu, Xiaoyu; Tao, Yong; Zhou, Yan; He, Xiaohong; Li, Daping

    2015-04-09

    The sulfate-reducing bioprocess is a promising technology for the treatment of heavy metal-containing wastewater. This work was conducted to investigate the possibility of promoting heavy metal removal by the addition of citrate to mask Ni2+ toxicity to sulfate-reducing bacteria (SRB) in batch reactors. SRB growth was completely inhibited in Ni2+-containing medium (1 mM) when lactate served as the sole carbon resource, leading to no sulfate reduction and Ni2+ removal. However, after the addition of citrate, SRB grew well, and sulfate was quickly reduced to sulfide. Simultaneously, the Ni-citrate complex was biodegraded to Ni2+ and acetate. The NiS precipitate was then formed, and Ni2+ was completely removed from the solution. It was suggested that the addition of citrate greatly alleviates Ni2+ toxicity to SRB and improves the removal of Ni2+, which was confirmed by quantitative real-time PCR targeting dissimilatory sulfite reductase (dsrAB) genes. Analysis of the carbon metabolism indicated that lactate instead of acetate served as the electron donor for sulfate reduction. This study offers a potential approach to increase the removal of heavy metals from wastewater in the single stage SRB-based bioprocess.

  4. Promotion of Ni2+ removal by masking toxicity to sulfate-reducing bacteria: addition of citrate.

    PubMed

    Qian, Junwei; Zhu, Xiaoyu; Tao, Yong; Zhou, Yan; He, Xiaohong; Li, Daping

    2015-01-01

    The sulfate-reducing bioprocess is a promising technology for the treatment of heavy metal-containing wastewater. This work was conducted to investigate the possibility of promoting heavy metal removal by the addition of citrate to mask Ni2+ toxicity to sulfate-reducing bacteria (SRB) in batch reactors. SRB growth was completely inhibited in Ni2+-containing medium (1 mM) when lactate served as the sole carbon resource, leading to no sulfate reduction and Ni2+ removal. However, after the addition of citrate, SRB grew well, and sulfate was quickly reduced to sulfide. Simultaneously, the Ni-citrate complex was biodegraded to Ni2+ and acetate. The NiS precipitate was then formed, and Ni2+ was completely removed from the solution. It was suggested that the addition of citrate greatly alleviates Ni2+ toxicity to SRB and improves the removal of Ni2+, which was confirmed by quantitative real-time PCR targeting dissimilatory sulfite reductase (dsrAB) genes. Analysis of the carbon metabolism indicated that lactate instead of acetate served as the electron donor for sulfate reduction. This study offers a potential approach to increase the removal of heavy metals from wastewater in the single stage SRB-based bioprocess. PMID:25860948

  5. COD removal characteristics in air-cathode microbial fuel cells.

    PubMed

    Zhang, Xiaoyuan; He, Weihua; Ren, Lijiao; Stager, Jennifer; Evans, Patrick J; Logan, Bruce E

    2015-01-01

    Exoelectrogenic microorganisms in microbial fuel cells (MFCs) compete with other microorganisms for substrate. In order to understand how this affects removal rates, current generation, and coulombic efficiencies (CEs), substrate removal rates were compared in MFCs fed a single, readily biodegradable compound (acetate) or domestic wastewater (WW). Removal rates based on initial test conditions fit first-order kinetics, but rate constants varied with circuit resistance. With filtered WW (100Ω), the rate constant was 0.18h(-)(1), which was higher than acetate or filtered WW with an open circuit (0.10h(-)(1)), but CEs were much lower (15-24%) than acetate. With raw WW (100Ω), COD removal proceeded in two stages: a fast removal stage with high current production, followed by a slower removal with little current. While using MFCs increased COD removal rate due to current generation, secondary processes will be needed to reduce COD to levels suitable for discharge.

  6. Energy and environmental research emphasizing low-rank coal -- Task 2.4, Air toxic fine particulate control

    SciTech Connect

    Dunham, G.E.; Heidt, M.K.; Miller, S.J.

    1995-03-01

    Emission from coal-fired boilers is an issue because of the current concern over atmospheric air toxics, which contain high concentrations of trace elements. The best method of minimizing the emission of these air toxic trace elements to the atmosphere is to install high-efficiency fine-particle control devices. After collection, the dust must be removed from the filter bags or electrostatic precipitator (ESP) plates and transferred to the hopper without significant redispersion. Since it is more difficult to collect fine particles, the extent to which the dust is redispersed into its original particle-size distribution will have a major impact on the overall fine-particle collection efficiency of the filter or ESP and, subsequently, the collection efficiency of air toxic metals. The goal of Task 2.4 was to evaluate redispersion of dust in particulate control devices so that the appropriate methods to minimize redispersion can be implemented. The primary objective was to determine the extent that fly ash is redispersed as individual particles upon cleaning of the filters or ESP plates. The current research was to determine if the level of redispersion of fly ash correlates with measurable cohesive dust properties. This will contribute to the long-term project goal of developing models to the point where they can be used to help design particulate control devices for the lowest level of fine-particle emissions at a reasonable cost.

  7. Combined anaerobic-ozonation process for treatment of textile wastewater: removal of acute toxicity and mutagenicity.

    PubMed

    Punzi, Marisa; Nilsson, Filip; Anbalagan, Anbarasan; Svensson, Britt-Marie; Jönsson, Karin; Mattiasson, Bo; Jonstrup, Maria

    2015-07-15

    A novel set up composed of an anaerobic biofilm reactor followed by ozonation was used for treatment of artificial and real textile effluents containing azo dyes. The biological treatment efficiently removed chemical oxygen demand and color. Ozonation further reduced the organic content of the effluents and was very important for the degradation of aromatic compounds, as shown by the reduction of UV absorbance. The acute toxicity toward Vibrio fischeri and the shrimp Artemia salina increased after the biological treatment. No toxicity was detected after ozonation with the exception of the synthetic effluent containing the highest concentration, 1 g/l, of the azo dye Remazol Red. Both untreated and biologically treated textile effluents were found to have mutagenic effects. The mutagenicity increased even further after 1 min of ozonation. No mutagenicity was however detected in the effluents subjected to longer exposure to ozone. The results of this study suggest that the use of ozonation as short post-treatment after a biological process can be beneficial for the degradation of recalcitrant compounds and the removal of toxicity of textile wastewater. However, monitoring of toxicity and especially mutagenicity is crucial and should always be used to assess the success of a treatment strategy.

  8. APPLICATION OF FINE SCALE AIR TOXICS MODELING WITH CMAQ TO HAPEM5

    EPA Science Inventory

    This paper provides a preliminary demonstration of the EPA neighborhood scale modeling paradigm for air toxics by linking concentration from the Community Multiscale Air Quality (CMAQ) modeling system to the fifth version of the Hazardous Pollutant Exposure Model (HAPEM5). For t...

  9. EPA'S CONTROL TECHNOLOGY APPROACH TO ASSISTING STATES AND REGIONS WITH AIR TOXICS PROBLEMS: FIVE CASE STUDIES

    EPA Science Inventory

    The paper discusses a new U.S. strategy to reduce public exposure to toxic air pollutants in the ambient air. he strategy calls for state and local authorities to take on more of the lead regulatory role. he shift in emphasis and responsibility prompted EPA's Offices of Research ...

  10. Carcinogenic Air Toxics Exposure and Their Cancer-Related Health Impacts in the United States

    PubMed Central

    Zhou, Ying; Li, Chaoyang; Huijbregts, Mark A. J.; Mumtaz, M. Moiz

    2015-01-01

    Public health protection from air pollution can be achieved more effectively by shifting from a single-pollutant approach to a multi-pollutant approach. To develop such multi-pollutant approaches, identifying which air pollutants are present most frequently is essential. This study aims to determine the frequently found carcinogenic air toxics or hazardous air pollutants (HAPs) combinations across the United States as well as to analyze the health impacts of developing cancer due to exposure to these HAPs. To identify the most commonly found carcinogenic air toxics combinations, we first identified HAPs with cancer risk greater than one in a million in more than 5% of the census tracts across the United States, based on the National-Scale Air Toxics Assessment (NATA) by the U.S. EPA for year 2005. We then calculated the frequencies of their two-component (binary), and three-component (ternary) combinations. To quantify the cancer-related health impacts, we focused on the 10 most frequently found HAPs with national average cancer risk greater than one in a million. Their cancer-related health impacts were calculated by converting lifetime cancer risk reported in NATA 2005 to years of healthy life lost or Disability-Adjusted Life Years (DALYs). We found that the most frequently found air toxics with cancer risk greater than one in a million are formaldehyde, carbon tetrachloride, acetaldehyde, and benzene. The most frequently occurring binary pairs and ternary mixtures are the various combinations of these four air toxics. Analysis of urban and rural HAPs did not reveal significant differences in the top combinations of these chemicals. The cumulative annual cancer-related health impacts of inhaling the top 10 carcinogenic air toxics included was about 1,600 DALYs in the United States or 0.6 DALYs per 100,000 people. Formaldehyde and benzene together contribute nearly 60 percent of the total cancer-related health impacts. Our study shows that although there are many

  11. Carcinogenic Air Toxics Exposure and Their Cancer-Related Health Impacts in the United States.

    PubMed

    Zhou, Ying; Li, Chaoyang; Huijbregts, Mark A J; Mumtaz, M Moiz

    2015-01-01

    Public health protection from air pollution can be achieved more effectively by shifting from a single-pollutant approach to a multi-pollutant approach. To develop such multi-pollutant approaches, identifying which air pollutants are present most frequently is essential. This study aims to determine the frequently found carcinogenic air toxics or hazardous air pollutants (HAPs) combinations across the United States as well as to analyze the health impacts of developing cancer due to exposure to these HAPs. To identify the most commonly found carcinogenic air toxics combinations, we first identified HAPs with cancer risk greater than one in a million in more than 5% of the census tracts across the United States, based on the National-Scale Air Toxics Assessment (NATA) by the U.S. EPA for year 2005. We then calculated the frequencies of their two-component (binary), and three-component (ternary) combinations. To quantify the cancer-related health impacts, we focused on the 10 most frequently found HAPs with national average cancer risk greater than one in a million. Their cancer-related health impacts were calculated by converting lifetime cancer risk reported in NATA 2005 to years of healthy life lost or Disability-Adjusted Life Years (DALYs). We found that the most frequently found air toxics with cancer risk greater than one in a million are formaldehyde, carbon tetrachloride, acetaldehyde, and benzene. The most frequently occurring binary pairs and ternary mixtures are the various combinations of these four air toxics. Analysis of urban and rural HAPs did not reveal significant differences in the top combinations of these chemicals. The cumulative annual cancer-related health impacts of inhaling the top 10 carcinogenic air toxics included was about 1,600 DALYs in the United States or 0.6 DALYs per 100,000 people. Formaldehyde and benzene together contribute nearly 60 percent of the total cancer-related health impacts. Our study shows that although there are many

  12. CONCURRENT INJECTION OF COSOLVENT AND AIR FOR ENHANCED PCE REMOVAL

    EPA Science Inventory

    The goal of this study was to use preferential flow of air to improve the dynamics of cosolvent displacement in order to enhance DNAPL displacement and dissolution. The concurrent injection of cosolvent and air was evaluated in a glass micromodel for a DNAPL remediation technolog...

  13. Removal of gasoline vapors from air streams by biofiltration

    SciTech Connect

    Apel, W.A.; Kant, W.D.; Colwell, F.S.; Singleton, B.; Lee, B.D.; Andrews, G.F.; Espinosa, A.M.; Johnson, E.G.

    1993-03-01

    Research was performed to develop a biofilter for the biodegradation of gasoline vapors. The overall goal of this effort was to provide information necessary for the design, construction, and operation of a commercial gasoline vapor biofilter. Experimental results indicated that relatively high amounts of gasoline vapor adsorption occur during initial exposure of the biofilter bed medium to gasoline vapors. Biological removal occurs over a 22 to 40[degrees]C temperature range with removal being completely inhibited at 54[degrees]C. The addition of fertilizer to the relatively fresh bed medium used did not increase the rates of gasoline removal in short term experiments. Microbiological analyses indicated that high levels of gasoline degrading microbes are naturally present in the bed medium and that additional inoculation with hydrocarbon degrading cultures does not appreciably increase gasoline removal rates. At lower gasoline concentrations, the vapor removal rates were considerably lower than those at higher gasoline concentrations. This implies that system designs facilitating gasoline transport to the micro-organisms could substantially increase gasoline removal rates at lower gasoline vapor concentrations. Test results from a field scale prototype biofiltration system showed volumetric productivity (i.e., average rate of gasoline degradation per unit bed volume) values that were consistent with those obtained with laboratory column biofilters at similar inlet gasoline concentrations. In addition, total benzene, toluene, ethyl-benzene, and xylene (BTEX) removal over the operating conditions employed was 50 to 55%. Removal of benzene was approximately 10 to 15% and removal of the other members of the BTEX group was much higher, typically >80%.

  14. Removal of gasoline vapors from air streams by biofiltration

    SciTech Connect

    Apel, W.A.; Kant, W.D.; Colwell, F.S.; Singleton, B.; Lee, B.D.; Andrews, G.F.; Espinosa, A.M.; Johnson, E.G.

    1993-03-01

    Research was performed to develop a biofilter for the biodegradation of gasoline vapors. The overall goal of this effort was to provide information necessary for the design, construction, and operation of a commercial gasoline vapor biofilter. Experimental results indicated that relatively high amounts of gasoline vapor adsorption occur during initial exposure of the biofilter bed medium to gasoline vapors. Biological removal occurs over a 22 to 40{degrees}C temperature range with removal being completely inhibited at 54{degrees}C. The addition of fertilizer to the relatively fresh bed medium used did not increase the rates of gasoline removal in short term experiments. Microbiological analyses indicated that high levels of gasoline degrading microbes are naturally present in the bed medium and that additional inoculation with hydrocarbon degrading cultures does not appreciably increase gasoline removal rates. At lower gasoline concentrations, the vapor removal rates were considerably lower than those at higher gasoline concentrations. This implies that system designs facilitating gasoline transport to the micro-organisms could substantially increase gasoline removal rates at lower gasoline vapor concentrations. Test results from a field scale prototype biofiltration system showed volumetric productivity (i.e., average rate of gasoline degradation per unit bed volume) values that were consistent with those obtained with laboratory column biofilters at similar inlet gasoline concentrations. In addition, total benzene, toluene, ethyl-benzene, and xylene (BTEX) removal over the operating conditions employed was 50 to 55%. Removal of benzene was approximately 10 to 15% and removal of the other members of the BTEX group was much higher, typically >80%.

  15. APPLICATION OF JET REMPI AND LIBS TO AIR TOXIC MONITORING

    EPA Science Inventory

    The paper discusses three advanced, laser-based monitoring techniques that the EPA is assisting in developing for real time measurement of toxic aerosol compounds. One of the three techniques is jet resonance enhanced multiphoton ionization (Jet REMPI) coupled with a time-of-flig...

  16. Epidemiologic evidence for asthma and exposure to air toxics: linkages between occupational, indoor, and community air pollution research.

    PubMed Central

    Delfino, Ralph J

    2002-01-01

    Outdoor ambient air pollutant exposures in communities are relevant to the acute exacerbation and possibly the onset of asthma. However, the complexity of pollutant mixtures and etiologic heterogeneity of asthma has made it difficult to identify causal components in those mixtures. Occupational exposures associated with asthma may yield clues to causal components in ambient air pollution because such exposures are often identifiable as single-chemical agents (e.g., metal compounds). However, translating occupational to community exposure-response relationships is limited. Of the air toxics found to cause occupational asthma, only formaldehyde has been frequently investigated in epidemiologic studies of allergic respiratory responses to indoor air, where general consistency can be shown despite lower ambient exposures. The specific volatile organic compounds (VOCs) identified in association with occupational asthma are generally not the same as those in studies showing respiratory effects of VOC mixtures on nonoccupational adult and pediatric asthma. In addition, experimental evidence indicates that airborne polycyclic aromatic hydrocarbon (PAH) exposures linked to diesel exhaust particles (DEPs) have proinflammatory effects on airways, but there is insufficient supporting evidence from the occupational literature of effects of DEPs on asthma or lung function. In contrast, nonoccupational epidemiologic studies have frequently shown associations between allergic responses or asthma with exposures to ambient air pollutant mixtures with PAH components, including black smoke, high home or school traffic density (particularly truck traffic), and environmental tobacco smoke. Other particle-phase and gaseous co-pollutants are likely causal in these associations as well. Epidemiologic research on the relationship of both asthma onset and exacerbation to air pollution is needed to disentangle effects of air toxics from monitored criteria air pollutants such as particle mass

  17. Epidemiologic evidence for asthma and exposure to air toxics: linkages between occupational, indoor, and community air pollution research.

    PubMed

    Delfino, Ralph J

    2002-08-01

    Outdoor ambient air pollutant exposures in communities are relevant to the acute exacerbation and possibly the onset of asthma. However, the complexity of pollutant mixtures and etiologic heterogeneity of asthma has made it difficult to identify causal components in those mixtures. Occupational exposures associated with asthma may yield clues to causal components in ambient air pollution because such exposures are often identifiable as single-chemical agents (e.g., metal compounds). However, translating occupational to community exposure-response relationships is limited. Of the air toxics found to cause occupational asthma, only formaldehyde has been frequently investigated in epidemiologic studies of allergic respiratory responses to indoor air, where general consistency can be shown despite lower ambient exposures. The specific volatile organic compounds (VOCs) identified in association with occupational asthma are generally not the same as those in studies showing respiratory effects of VOC mixtures on nonoccupational adult and pediatric asthma. In addition, experimental evidence indicates that airborne polycyclic aromatic hydrocarbon (PAH) exposures linked to diesel exhaust particles (DEPs) have proinflammatory effects on airways, but there is insufficient supporting evidence from the occupational literature of effects of DEPs on asthma or lung function. In contrast, nonoccupational epidemiologic studies have frequently shown associations between allergic responses or asthma with exposures to ambient air pollutant mixtures with PAH components, including black smoke, high home or school traffic density (particularly truck traffic), and environmental tobacco smoke. Other particle-phase and gaseous co-pollutants are likely causal in these associations as well. Epidemiologic research on the relationship of both asthma onset and exacerbation to air pollution is needed to disentangle effects of air toxics from monitored criteria air pollutants such as particle mass

  18. Distribution of toxic and radiation components in air particulates.

    PubMed

    Rausch, H; Sziklai, I L; Borossay, J; Torkos, K; Rikker, T; Zemplén-Papp, E

    1995-12-01

    The concentrations of several toxic heavy metals and volatile organic compounds (VOCs) in various types of Hungarian fly-ash fine particulates were investigated by means of instrumental neutron activation analysis, X-ray fluorescence analysis and gas chromatography, coupled with mass spectrometry. Within a power station, particulate samples were taken from the boiler zone (BO), from the electrostatic dust filter chamber (FI) and from the flue-gas at the top of the stack (ST). Enrichment rates of the toxic metals both in FI and ST particulate fractions related to the BO concentrations were calculated to enable the temperature dependence on the adsorption of the toxic components to be studied. In addition, both the total amounts of the VOCs and their partial distributions in accordance with the number of carbon atoms were also studied in fly-ash particulates. From them, 31 organic species were identified and determined. Since Hungarian brown coals have high uranium and thorium contents, the specific radioactivities of the daughter isotopes of both the 232Th and 238U decay series were also measured and are discussed.

  19. Removal of landfill leachate toxicity and genotoxicity by two treatment methods.

    PubMed

    Brkanac, Sandra Radić; Vujčić, Valerija; Cvjetko, Petra; Baković, Vid; Oreščanin, Višnja

    2014-03-01

    Leachates from active and closed municipal solid waste landfills can be a major source of contamination to groundwater and surface waters. In the present study the toxic and genotoxic potential of leachate from an old sanitary landfill prior to and following chemical and electrochemical treatments were assessed using Lemna, Allium, and comet tests. Photosynthetic pigments, malondialdehyde (indicator of lipid peroxidation) and antioxidant enzyme activities were evaluated as additional indicators of toxicity in duckweed. Following duckweed exposure to 25 % dilution of landfill leachate, growth rate and photosynthetic pigments content significantly decreased while lipid peroxidation increased despite stimulation of antioxidative defence mechanisms. Diluted leachate induced DNA strand breaks in duckweed cells as evidenced by the comet assay. Regarding the Allium test, untreated leachate caused inhibition of Allium cepa cell division and induction of mitotic and chromosomal aberrations. Although both water treatments completely reduced genotoxicity of leachate, the electrochemical method was found to be more efficient in removing toxic substances present in landfill leachate and thus more suitable for treating such leachates prior to their discharge into the environment. As landfill leachates pose a risk to human health and environment in general due to their (geno)toxicity, the present study demonstrates that the ecotoxicity/genotoxicity assays should be used in leachate risk assessment together with physicochemical analysis.

  20. Formaldehyde: a candidate toxic air contaminant. Final report

    SciTech Connect

    Frye, B.; Parker, T.

    1988-03-01

    Formaldehyde (HCHO) is a gas widely used in adhesives and resins, textiles, embalming fluids, fungicides, air fresheners, and cosmetics. It is directly emitted into the ambient outdoor air from vehicular and stationary sources, and is also produced in the atmosphere from other substances by photochemical smog processes. The International Agency for Research on Cancer (IARC) has determined that there is sufficient evidence for carcinogenicity of formaldehyde to animals, and limited evidence for carcinogenicity to humans. EPA classifies formaldehyde as a probable human carcinogen with a one in a million risk concentration of 0.08 ppb.

  1. Toxic treatments 'in-situ' steam/hot-air stripping technology. Applications analysis report. Rept. for Jun 89-Jun 90

    SciTech Connect

    Jackson, T.

    1991-03-01

    A SITE Demonstration of the Toxic Treatment (USA) Inc. in-situ steam/hot-air stripping technology (Detoxifier) was conducted beginning in the fall of 1989 at the GATX Annex Terminal site located in San Pedro, CA. The chemical storage and transfer facility was contaminated with various solvents due to spillage and a fire. Contamination extended into the salt water table (1.8 meters). Based on the SITE Demonstration and other data, it was concluded that 85% of the volatile organic compounds and 50% of the semivolatile organic compounds were removed from the soil. Fugitive air emissions are very low, and lateral and downward migration of contaminants due to the treatment were minimal. Finally, it was concluded that this in-situ process is cost competitive.

  2. Polyurethane and alginate immobilized algal biomass for the removal of aqueous toxic metals

    SciTech Connect

    Fry, I.V.; Mehlhorn, R.J.

    1992-12-01

    We describe the development of immobilized, processed algal biomass for use as an adsorptive filter in the removal of toxic metals from waste water. To fabricate an adsorptive filter from precessed biomass several crucial criteria must be met, including: (1) high metal binding capacity, (2) long term stability (both mechanical and chemical), (3) selectivity for metals of concern (with regard to ionic competition), (4) acceptable flow capacity (to handle large volumes in short time frames), (5) stripping/regeneration (to recycle the adsorptive filter and concentrate the toxic metals to manageable volumes). This report documents experiments with processed algal biomass (Spirulina platensis and Spirulina maxima) immobilized in either alginate gel or preformed polyurethane foam. The adsorptive characteristics of these filters were assessed with regard to the criteria listed above.

  3. Selective removal of organic contaminants from sediments: A methodology for toxicity identification evaluations (TIEs)

    USGS Publications Warehouse

    Lebo, J.A.; Huckins, J.N.; Petty, J.D.; Ho, K.T.; Stern, E.A.

    2000-01-01

    Aqueous slurries of a test sediment spiked with dibenz[a,h]anthracene, 2,4,5,2',4',5'-hexachlorobiphenyl, p,p'-DDE, or phenanthrene were subjected to decontamination experimentation. The spiked sediments were agitated at elevated temperatures for at least 96 h in the presence of either of the two contaminant-absorbing media: clusters of polyethylene membrane or lipid- containing semipermeable membrane devices (SPMDs). The effects of treatment temperature and surface area of media on the removal of contaminants were explored. This work is part of a larger methodology for whole-sediment toxicity identification evaluation (TIE). A method is being sought that is capable of detoxifying sediments with respect to organic contaminants while leaving toxicity attributable to inorganic contaminants unaffected. (C) 2000 Elsevier Science Ltd.

  4. Removal of persistent bioaccumulative toxic chemicals from pulp and paper mill effluent streams

    SciTech Connect

    Holm, S.E.

    1995-12-31

    Several organizations have called for the reduction of PBTs or Persistent Bioaccumulative Toxics because of this class of chemicals potential environmental consequences when released into the environment. PBTs are persistent because of their resistance to biological contamination, because they bioaccumulate in the fatty tissue of organisms, and are toxic to aquatic species at relatively low levels. PBTs may be produced commercially such as for use as a pesticide or herbicide or inadvertently as byproducts, such as from diesel engines, incinerators, and during pulp bleaching using chlorine or chlorine derivatives. This paper will show how the pulp and paper industry has utilized the pollution prevention technique of process change to remove the levels of PBTs from its waste stream and how this process change relates to decreasing levels of specific PBTs in the environment. Chlorinated phenolic compounds and dioxin will be used as examples.

  5. Production of toxic shock syndrome toxin 1 by Staphylococcus aureus restricted to endogenous air in tampons.

    PubMed

    Reiser, R F; Hinzman, S J; Bergdoll, M S

    1987-08-01

    All types of four brands of tampons were tested in triplicate by a tampon sac method for their effect on production of toxic shock syndrome toxin 1 (TSST-1). In this method the available air is limited to that which is in the tampon sac. Tampons were weighed and inserted into dialysis sacs inoculated with a TSST-1-producing Staphylococcus aureus strain; the sacs were submerged into brain heart infusion agar, which was allowed to harden around the sacs, and were incubated for 18 h at 37 degrees C. The tampons were removed, weighed, and extracted; the CFU of staphylococci and the amount of toxin present in the extracts were determined. Glass wool was used in place of the tampons as one control, and inoculated empty sacs were used as a second control. The total CFU were consistently greater than 2 X 10(11) for the tampons and glass wool and less than or equal to 10(11) for the empty sac control. Total toxin production for all tampons tested and the glass wool was 2 to 10 times higher than the toxin produced with the empty sac control. These results indicate that tampons provide increased surface area for the staphylococci to grow and adequate oxygen for toxin production. No significant inhibition of growth of the staphylococci or TSST-1 production by any of the tampons tested was noted.

  6. Indoor/ambient residential air toxics results in rural western Montana.

    PubMed

    Ward, Tony J; Underberg, Heidi; Jones, David; Hamilton, Raymond F; Adams, Earle

    2009-06-01

    Indoor and ambient concentrations of 21 volatile organic compounds (including 14 hazardous air pollutants) were measured in the homes of nearly 80 western Montana (Missoula) high school students as part of the 'Air Toxics Under the Big Sky' program during the 2004/2005 and 2005/2006 school years. Target analytes were measured using low flow air sampling pumps and sorbent tubes, with analysis of the exposed samples by thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS). The results reported here present the findings of the first indoor/ambient air toxics monitoring program conducted in a semi-rural valley location located in the Northern Rocky Mountain/Western Montana region. Of all of the air toxics quantified in this study, toluene was found to be the most abundant compound in both the indoor and ambient environments during each of the two school years. Indoor log-transformed mean concentrations were found to be higher when compared with ambient log-transformed mean concentrations at P < 0.001 for the majority of the compounds, supporting the results of previous studies conducted in urban areas. For the air toxics consistently measured throughout this program, concentrations were approximately six times higher inside the student's homes compared to those simultaneously measured directly outside their homes. For the majority of the compounds, there were no significant correlations between indoor and ambient concentrations.

  7. Multipass membrane air-stripping (MAS) for removing volatile organic compounds (VOCs) from surfactant micellar solutions.

    PubMed

    Cheng, Hefa; Hu, Yuanan; Luo, Jian; Sabatini, David A

    2009-10-30

    Air-stripping is one of the most effective technologies for removing volatile organic compounds (VOCs) from surfactant solutions, although the presence of surfactant poses some unique challenges. This study evaluated the effect of a mixed surfactant system on the apparent Henry's law constant of tetrachloroethylene (PCE) and the efficiency of PCE removal from surfactant solutions using a lab-scale hollow fiber membrane contactor. Results show that the presence of surfactant significantly reduced the apparent Henry's law constant of PCE, and the reduction was proportional to the total surfactant concentration. PCE removal efficiency by membrane air-stripping (MAS) decreased as the surfactant system transitioned from solubilization to supersolubilization. Besides significantly reducing the apparent volatility of VOCs, the presence of surfactant brings additional mass transfer resistance in air-stripping, which makes it difficult to achieve high levels of contaminant removal, even at very high air/liquid (A/L) ratios. In contrast, multipass/multistage MAS operated at low A/L ratios could achieve near 100% contaminant removal because of less mass transfer limitation during each stripping pass/stage. Experimental results, together with model calculations demonstrate multipass (and multistage) air-stripping as a cost-effective alternative for removing VOCs from surfactant micellar solutions compared to the options of using large air strippers or operating at high A/L ratios.

  8. Development Of Chemical Reduction And Air Stripping Processes To Remove Mercury From Wastewater

    SciTech Connect

    Jackson, Dennis G.; Looney, Brian B.; Craig, Robert R.; Thompson, Martha C.; Kmetz, Thomas F.

    2013-07-10

    This study evaluates the removal of mercury from wastewater using chemical reduction and air stripping using a full-scale treatment system at the Savannah River Site. The existing water treatment system utilizes air stripping as the unit operation to remove organic compounds from groundwater that also contains mercury (C ~ 250 ng/L). The baseline air stripping process was ineffective in removing mercury and the water exceeded a proposed limit of 51 ng/L. To test an enhancement to the existing treatment modality a continuous dose of reducing agent was injected for 6-hours at the inlet of the air stripper. This action resulted in the chemical reduction of mercury to Hg(0), a species that is removable with the existing unit operation. During the injection period a 94% decrease in concentration was observed and the effluent satisfied proposed limits. The process was optimized over a 2-day period by sequentially evaluating dose rates ranging from 0.64X to 297X stoichiometry. A minimum dose of 16X stoichiometry was necessary to initiate the reduction reaction that facilitated the mercury removal. Competing electron acceptors likely inhibited the reaction at the lower 1 doses, which prevented removal by air stripping. These results indicate that chemical reduction coupled with air stripping can effectively treat large-volumes of water to emerging part per trillion regulatory standards for mercury.

  9. EMISSIONS OF AIR TOXICS FROM A SIMULATED CHARCOAL KILN

    EPA Science Inventory

    The report gives results of experiments in a laboratory-scale charcoal kiln simulator to evaluate emissions of hazardous air pollutants from the production of charcoal in Missouri-type kilns. Fixed combustion gases were measured using continuous monitors. In Addition, other pollu...

  10. MEASUREMENT OF LOW LEVEL AIR TOXICS WITH MODIFIED UV DOAS

    EPA Science Inventory

    To further understand near source impacts, EPA is working to develop open-path optical techniques for spatiotemporal-resolved measurement of air pollutants. Of particular interest is near real time quantification of mobile-source generated CO, Nox and hydrocarbons measured in cl...

  11. SIMULATING URBAN AIR TOXICS OVER CONTINENTAL AND URBAN SCALES

    EPA Science Inventory

    The US EPA is evaluating a version of the CMAQ model to support risk assessment for the exposure to Hazardous Air Pollutants (HAPs). The model uses a variant of the CB4 chemical mechanism to simulate ambient concentrations of twenty HAPs that exist primarily as gaseous compounds...

  12. Experimental study on sulfur removal from ladle furnace refining slag in hot state by blowing air

    NASA Astrophysics Data System (ADS)

    Zhao, Li-hua; Lin, Lu; Wu, Qi-fan

    2016-01-01

    In view of the present problem of sulfur enrichment in the metallurgical recycling process of ladle furnace (LF) refining slag, a simple and efficient method of removing sulfur from this slag was proposed. The proposed method is compatible with current steelmaking processes. Sulfur removal from LF refining slag for SPHC steel (manufactured at a certain steel plant in China) by blowing air in the hot state was studied by using hot-state experiments in a laboratory. The FactSage software, a carbon/sulfur analyzer, and scanning electron microscopy in conjunction with energy-dispersive X-ray spectroscopy were used to test and analyze the sulfur removal effect and to investigate factors influencing sulfur removal rate. The results show that sulfur ions in LF refining slag can be oxidized into SO2 by O2 at high temperature by blowing air into molten slag; SO2 production was observed to reach a maximum with a small amount of blown O2 when the temperature exceeded 1350°C. At 1370°C and 1400°C, experimental LF refining slag is in the liquid state and exhibits good fluidity; under these conditions, the sulfur removal effect by blowing air is greater than 90wt% after 60 min. High temperature and large air flow rate are beneficial for removing sulfur from LF refining slag; compared with air flow rate, temperature has a greater strongly influences on the sulfur removal.

  13. Removal of volatile and semivolatile organic contamination from soil by air and steam flushing.

    PubMed

    Sleep, B E; McClure, P D

    2001-07-01

    A soil core, obtained from a contaminated field site, contaminated with a mixture of volatile and semivolatile organic compounds (VOC and SVOC) was subjected to air and steam flushing. Removal rates of volatile and semivolatile organic compounds were monitored during flushing. Air flushing removed a significant portion of the VOC present in the soil, but a significant decline in removal rate occurred due to decreasing VOC concentrations in the soil gas phase. Application of steam flushing after air flushing produced a significant increase in contaminant removal rate for the first 4 to 5 pore volumes of steam condensate. Subsequently, contaminant concentrations decreased slowly with additional pore volumes of steam flushing. The passage of a steam volume corresponding to 11 pore volumes of steam condensate reduced the total VOC concentration in the soil gas (at 20 degrees C) by a factor of 20 to 0.07 mg/l. The corresponding total SVOC concentration in the condensate declined from 11 to 3 mg/l. Declines in contaminant removal rates during both air and steam flushing indicated rate-limited removal consistent with the persistence of a residual organic phase, rate-limited desorption, or channeling. Pressure gradients were much higher for steam flushing than for air flushing. The magnitude of the pressure gradients encountered during steam flushing for this soil indicates that, in addition to rate-limited contaminant removal, the soil permeability (2.1 x 10(-9) cm2) would be a limiting factor in the effectiveness of steam flushing. PMID:11475159

  14. 78 FR 40011 - Approval and Promulgation of Air Quality Implementation Plans; Virginia; Removal of Consumer and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-03

    ... AGENCY 40 CFR Part 52 ; FRL-9828-2 Approval and Promulgation of Air Quality Implementation Plans... Virginia State Implementation Plan (SIP). The revisions remove four articles located in chapter 9VAC5-40 (Existing Stationary Sources) from the Virginia SIP. These articles are being removed from the Virginia...

  15. Removal of contaminated air scrubbers at TA-35-7, Los Alamos National Laboratory

    SciTech Connect

    Harper, J.R.; Garde, R.

    1981-11-01

    Five large excess contaminated air scrubbers located in Building 7 at TA-35 were removed and disposed of in 1979 to 1980. The scrubbers were contaminated with strontium-yttrium and cesium. This report details the removal procedures, the health physics program, the waste management program, and the costs of the operation.

  16. An empirical analysis of exposure-based regulation to abate toxic air pollution

    SciTech Connect

    Marakovits, D.M.; Considine, T.J.

    1996-11-01

    Title III of the 1990 Clean Air Act Amendments requires the Environmental Protection Agency to regulate 189 air toxics, including emissions from by-product coke ovens. Economists criticize the inefficiency of uniform standards, but Title III makes no provision for flexible regulatory instruments. Environmental health scientists suggest that population exposure, not necessarily ambient air quality, should motivate environmental air pollution policies. Using an engineering-economic model of the United States steel industry, we estimate that an exposure-based policy can achieve the same level of public health as coke oven emissions standards and can reduce compliance costs by up to 60.0%. 18 refs., 3 figs., 1 tab.

  17. Development of an air knife to remove seed coat fragments during lint cleaning

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An air knife is a tool commonly used to blow off debris in a manufacturing line. The knife may also be used to break the attachment force between a lint cleaner saw and a seed coat fragment (SCF) with attached fiber, and remove them. Work continued on evaluating an auxiliary air knife mounted on t...

  18. DNAPL REMOVAL MECHANISMS AND MASS TRANSFER CHARACTERISTICS DURING COSOLVENT-AIR FLOODING

    EPA Science Inventory

    The concurrent injection of cosolvent and air, a cosolvent-air (CA) flood was recently suggested for a dense nonaqueous phase liquid (DNAPL) remediation technology. The objectives of this study were to elucidate the DNAPL removal mechanisms of the CA flood and to quantify mass t...

  19. Removing seed coat fragments with a lint cleaner grid bar air knife

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seed coat fragments (SCF) in ginned lint cause spinning problems at the textile mill and undesirable defects in finished goods. Work continued on developing an air knife that may help remove SCF from ginned lint. The air knife is mounted on the 1st lint cleaner grid bar of a saw-type lint cleaner,...

  20. Fast removal of high quantities of toxic arsenate via cationic p(APTMACl) microgels.

    PubMed

    Rehman, Saif Ur; Siddiq, Mohammed; Al-Lohedan, Hamad; Aktas, Nahit; Sahiner, Mehtap; Demirci, Sahin; Sahiner, Nurettin

    2016-01-15

    Hydrogels are resourceful materials and can be prepared in different morphology, size, surface charge and porosity adopting different polymerization techniques and reaction conditions. The cationic poly(3-acrylamidopropyl)trimethylammonium chloride (p(APTMACl)) microgels were synthesized by photo-initiated inverse suspension polymerization technique. These microgels were utilized as absorbents for the removal of toxic arsenate (As) from different aqueous environments. The experimental parameters affecting absorption efficiency were investigated, and it was demonstrated that these types of microgels are highly efficient in removing arsenate anions from different aqueous environments compared to the previously reported bulk hydrogel, and cryogel of the same material. A removal efficiency of approximately 97.25% was obtained by immersing 0.5 g microgel in 250 ppm 100 mL solution of arsenate anions for 60 min. Both Langmuir and Freundlich adsorption isotherms were applied to adsorption of arsenate anions by p(APTMACl) microgels, and the Langmuir isotherm was a better representation of the adsorption of arsenate with a high value of R(2) (0.9982). Furthermore, mag-p(APTMACl) microgels were synthesized for the adsorption of arsenate anions to provide easy removal of the microgel composite by using an externally applied magnetic field. Furthermore, re-usability of the p(APTMACl) microgels was also investigated for the adsorption of arsenate anions.

  1. Preliminary evaluation of a membrane-based system for removing CO2 from air

    NASA Technical Reports Server (NTRS)

    Mccray, Scott B.; Wytcherley, Randi W.; Friesen, Dwayne T.; Ray, Rod J.

    1990-01-01

    Processes to remove and/or recover CO2 from air are essential to the long-term success of the U.S. space program. The results of a preliminary investigation of the use of a novel membrane-based system for removal of CO2 from air are presented. Features of this technology that make it attractive include the following: (1) it is lightweight; (2) it requires no consumables or expendables; (3) it is relatively simple; and (4) it does not rely directly on other subsystems. Preliminary designs of systems for removing CO2 from spacecraft cabin atmospheres and from the extravehicular mobility unit are presented.

  2. Toxicity, accumulation, and removal of heavy metals by three aquatic macrophytes.

    PubMed

    Basile, A; Sorbo, S; Conte, B; Cobianchi, R Castaldo; Trinchella, F; Capasso, C; Carginale, V

    2012-04-01

    A comprehensive understanding of the uptake, tolerance, and transport of heavy metals by plants will be essential for the development of phytoremediation technologies. In the present paper, we investigated accumulation, tissue and intracellular localization, and toxic effects of cadmium (Cd), lead (Pb), zinc (Zn), and copper (Cu) in three aquatic macrophytes (the angiosperms Lemna minor and Elodea canadensis, and the moss Leptodictyum riparium). We also tested and compared their capacity to absorb heavy metal from water under laboratory conditions. Our data showed that all the three species examined could be considered good bioaccumulators for the heavy metals tested. L. riparium was the most resistant species and the most effective in accumulating Cu, Zn, and Pb, whereas L. minor was the most effective in accumulating Cd. Cd was the most toxic metal, followed by Pb, Cu, and Zn. At the ultrastructural level, sublethal concentrations of the heavy metals tested caused induced cell plasmolysis and alterations of the chloroplast arrangement. Heavy metal removal experiments revealed that the three macrophytes showed excellent performance in removing the selected metals from the solutions in which they are maintained, thus suggesting that they could be considered good candidates for wastewaters remediation purpose.

  3. Toxicity, accumulation, and removal of heavy metals by three aquatic macrophytes.

    PubMed

    Basile, A; Sorbo, S; Conte, B; Cobianchi, R Castaldo; Trinchella, F; Capasso, C; Carginale, V

    2012-04-01

    A comprehensive understanding of the uptake, tolerance, and transport of heavy metals by plants will be essential for the development of phytoremediation technologies. In the present paper, we investigated accumulation, tissue and intracellular localization, and toxic effects of cadmium (Cd), lead (Pb), zinc (Zn), and copper (Cu) in three aquatic macrophytes (the angiosperms Lemna minor and Elodea canadensis, and the moss Leptodictyum riparium). We also tested and compared their capacity to absorb heavy metal from water under laboratory conditions. Our data showed that all the three species examined could be considered good bioaccumulators for the heavy metals tested. L. riparium was the most resistant species and the most effective in accumulating Cu, Zn, and Pb, whereas L. minor was the most effective in accumulating Cd. Cd was the most toxic metal, followed by Pb, Cu, and Zn. At the ultrastructural level, sublethal concentrations of the heavy metals tested caused induced cell plasmolysis and alterations of the chloroplast arrangement. Heavy metal removal experiments revealed that the three macrophytes showed excellent performance in removing the selected metals from the solutions in which they are maintained, thus suggesting that they could be considered good candidates for wastewaters remediation purpose. PMID:22567718

  4. The use of biofilters to improve indoor air quality: the removal of toluene, TCE, and formaldehyde.

    PubMed

    Darlington, A; Dixon, M A; Pilger, C

    1998-01-01

    A biofilter composed of a scrubber, a hydroponic planting system, and an aquatic system with green plants as a base maintained air quality within part of a modern office building. The scrubber was composed of five parallel fiberglass modules with external faces of porous lava rock. The face, largely covered with mosses, was wetted by recirculating water. Air was drawn through the scrubber and the immediately adjacent hydroponic region by a dedicated air handling system. The system was challenged for 4 weeks with three common indoor organic pollutants and removed significant amounts of all compounds. A single pass through the scrubber removed 10% of the trichloroethylene and 50% of the toluene. A single pass lowered formaldehyde air concentrations to 13 micrograms m-3 irrespective of influent levels (ranging between 30 and 90 micrograms m-3). The aquatic system accumulated trichloroethylene but neither toluene nor formaldehyde, suggesting the rapid breakdown of these materials. The botanical components removed some pollutants.

  5. Risk of leukemia in relation to exposure to ambient air toxics in pregnancy and early childhood.

    PubMed

    Heck, Julia E; Park, Andrew S; Qiu, Jiaheng; Cockburn, Myles; Ritz, Beate

    2014-07-01

    There are few established causes of leukemia, the most common type of cancer in children. Studies in adults suggest a role for specific environmental agents, but little is known about any effect from exposures in pregnancy to toxics in ambient air. In our case-control study, we ascertained 69 cases of acute lymphoblastic leukemia (ALL) and 46 cases of acute myeloid leukemia (AML) from California Cancer Registry records of children air toxics monitoring station between 1990 and 2007. Information on air toxics exposures was taken from community air monitors. We used logistic regression to estimate the risk of leukemia associated with one interquartile range increase in air toxic exposure. Risk of ALL was elevated with 3(rd) trimester exposure to polycyclic aromatic hydrocarbons (OR=1.16, 95% CI 1.04, 1.29), arsenic (OR=1.33, 95% CI 1.02, 1.73), benzene (OR=1.50, 95% CI 1.08, 2.09), and three other toxics related to fuel combustion. Risk of AML was increased with 3rd trimester exposure to chloroform (OR=1.30, 95% CI 1.00, 1.69), benzene (1.75, 95% CI 1.04, 2.93), and two other traffic-related toxics. During the child's first year, exposure to butadiene, ortho-xylene, and toluene increased risk for AML and exposure to selenium increased risk for ALL. Benzene is an established cause of leukemia in adults; this study supports that ambient exposures to this and other chemicals in pregnancy and early life may also increase leukemia risk in children.

  6. Risk of leukemia in relation to exposure to ambient air toxics in pregnancy and early childhood

    PubMed Central

    Heck, Julia E; Park, Andrew S; Qiu, Jiaheng; Cockburn, Myles; Ritz, Beate

    2014-01-01

    There are few established causes of leukemia, the most common type of cancer in children. Studies in adults suggest a role for specific environmental agents, but little is known about any effect from exposures in pregnancy to toxics in ambient air. In our case-control study, we ascertained 69 cases of acute lymphoblastic leukemia (ALL) and 46 cases of acute myeloid leukemia (AML) from California Cancer Registry records of children < age 6, and 19,209 controls from California birth records within 2km (1.3 miles) (ALL) and 6km (3.8 miles) (AML) of an air toxics monitoring station between 1990–2007. Information on air toxics exposures was taken from community air monitors. We used logistic regression to estimate the risk of leukemia associated with one interquartile range increase in air toxic exposure. Risk of ALL was elevated with 3rd trimester exposure to polycyclic aromatic hydrocarbons (OR=1.16, 95%CI 1.04, 1.29), arsenic (OR=1.33, 95%CI 1.02, 1.73), benzene (OR=1.50, 95%CI 1.08, 2.09), and three other toxics related to fuel combustion. Risk of AML was increased with 3rd trimester exposure to chloroform (OR=1.30, 95%CI 1.00, 1.69), benzene (1.75, 95%CI 1.04, 2.93), and two other traffic-related toxics. During the child’s first year, exposure to butadiene, ortho-xylene, and toluene increased risk for AML and exposure to selenium increased risk for ALL. Benzene is an established cause of leukemia in adults; this study supports that ambient exposures to this and other chemicals in pregnancy and early life may also increase leukemia risk in children. PMID:24472648

  7. Process for removal of hazardous air pollutants from coal

    DOEpatents

    Akers, David J.; Ekechukwu, Kenneth N.; Aluko, Mobolaji E.; Lebowitz, Howard E.

    2000-01-01

    An improved process for removing mercury and other trace elements from coal containing pyrite by forming a slurry of finely divided coal in a liquid solvent capable of forming ions or radicals having a tendency to react with constituents of pyrite or to attack the bond between pyrite and coal and/or to react with mercury to form mercury vapors, and heating the slurry in a closed container to a temperature of at least about 50.degree. C. to produce vapors of the solvent and withdrawing vapors including solvent and mercury-containing vapors from the closed container, then separating mercury from the vapors withdrawn.

  8. Toxic Acid Gas Absorber Design Considerations for Air Pollution Control in Process Industries

    ERIC Educational Resources Information Center

    Manyele, S. V.

    2008-01-01

    This paper analyses the design parameters for an absorber used for removal of toxic acid gas (in particular sulfur dioxide) from a process gas stream for environmental health protection purposes. Starting from the equilibrium data, Henry's law constant was determined from the slope of the y-x diagram. Based on mass balances across the absorber,…

  9. Air toxic emissions from the combustion of coal: Identifying and quantifying hazardous air pollutants from US coals

    SciTech Connect

    Szpunar, C.B.

    1992-09-01

    This report addresses the key air toxic emissions likely to emanate from continued and expanded use of domestic coal. It identifies and quantifies those trace elements specified in the US 1990 Clean Air Act Amendments, by tabulating selected characterization data on various source coals by region, state, and rank. On the basis of measurements by various researchers, this report also identifies those organic compounds likely to be derived from the coal combustion process (although their formation is highly dependent on specific boiler configurations and operating conditions).

  10. Removal of volatile organics from humidified air streams by absorption. Final report, July 1985-March 1987

    SciTech Connect

    Coutant, R.W.; Zwick, T.; Kim, B.C.

    1987-12-01

    The Air Force frequently relies on air-stripping technologies to remove organic chemicals from ground waters contaminated from fuel and solvent spills. Although air stripping is extremely efficient at removing contaminants from the groundwater, these contaminants are only transferred into the air and in several states, air pollution controls are also required. Activated-carbon beds are one potential emissions control under study. The objective of this study was to determine the effects of contaminant concentration, humidity, and chemical competition on the sorption performance of activated carbons. Based on laboratory results, a preliminary cost comparison was made for heated and unheated carbon beds. Volatile organics of interest included benzene, ethyl benzene, toluene, xylenes. trichloroethylene, and 1,1-dichloroethylene.

  11. Air toxics being measured more accurately, controlled more effectively

    SciTech Connect

    1995-04-01

    In response to the directives of the Clean Air Act Amendments, Argonne National Laboratory is developing new or improved pollutant control technologies for industries that burn fossil fuels. This research continues Argonne`s traditional support for the US DOE Flue Gas Cleanup Program. Research is underway to measure process emissions and identify new and improved control measures. Argonne`s emission control research has ranged from experiments in the basic chemistry of pollution-control systems, through laboratory-scale process development and testing to pilot-scale field tests of several technologies. Whenever appropriate, the work has emphasized integrated or combined control systems as the best approach to technologies that offer low cost and good operating characteristics.

  12. Toxicity Minimized Cryoprotectant Addition and Removal Procedures for Adherent Endothelial Cells

    PubMed Central

    Davidson, Allyson Fry; Glasscock, Cameron; McClanahan, Danielle R.; Benson, James D.; Higgins, Adam Z.

    2015-01-01

    Ice-free cryopreservation, known as vitrification, is an appealing approach for banking of adherent cells and tissues because it prevents dissociation and morphological damage that may result from ice crystal formation. However, current vitrification methods are often limited by the cytotoxicity of the concentrated cryoprotective agent (CPA) solutions that are required to suppress ice formation. Recently, we described a mathematical strategy for identifying minimally toxic CPA equilibration procedures based on the minimization of a toxicity cost function. Here we provide direct experimental support for the feasibility of these methods when applied to adherent endothelial cells. We first developed a concentration- and temperature-dependent toxicity cost function by exposing the cells to a range of glycerol concentrations at 21°C and 37°C, and fitting the resulting viability data to a first order cell death model. This cost function was then numerically minimized in our state constrained optimization routine to determine addition and removal procedures for 17 molal (mol/kg water) glycerol solutions. Using these predicted optimal procedures, we obtained 81% recovery after exposure to vitrification solutions, as well as successful vitrification with the relatively slow cooling and warming rates of 50°C/min and 130°C/min. In comparison, conventional multistep CPA equilibration procedures resulted in much lower cell yields of about 10%. Our results demonstrate the potential for rational design of minimally toxic vitrification procedures and pave the way for extension of our optimization approach to other adherent cell types as well as more complex systems such as tissues and organs. PMID:26605546

  13. Water quality-based toxics evaluation of Reconquista River, Province of Buenos Aires, Argentina

    SciTech Connect

    Herkovits, J.; Herkovits, F.D.; Perez-Coll, C.S.

    1995-12-31

    The water quality based toxics control is essential to evaluate the aggregate toxicity, bioavailability as well as for the detection and/or prediction of ecological impacts. Reconquista River valley is situated in the north area of Great Buenos Aires with a population of three million inhabitants. The river is loaded with industrial and municipal waste water. In the present preliminary study the authors report the toxicity found in surface water at a 6 sample stations (including a reference point and a stream) all of them downstream from mixing zone areas. The ecotoxicological study was performed with three native species (Bufo arenarum embryos, Cnesterodon decemmaculatus and a species of shrimp collected in an upstream reference site) during a 7 day renewal toxicity test conducted with 10 individuals (by duplicate) for each condition plus control. The results point out that the Bufo arenarum embryos test is the most sensitive to toxic substances as well as the better adapted species to the changing physico-chemical conditions of this river. The results obtained with embryos, expressed in Acute and Chronic Toxicity Units (according USEPA) range between <0.3--2 and <1--5 respectively (recommended magnitudes for industrial effluents according USEPA: 0.3 and 1 toxicity units respectively). Therefore, the toxicity found in Reconquista River ecosystem was up to 6 times higher than the maximal value recommended for industrial effluents. It is noteworthy that in the place where toxicity starts to rise, a large number of dead fishes were found and from that place downstream, no macroorganisms were found in the river. The results confirm the high sensitivity of Bufo arenarum embryos for continental waters ecotoxicological studies and the possibility of using this test as a short-term chronic toxicity method for water quality-based toxics control.

  14. APPLICATIONS ANALYSIS REPORT: TOXIC TREATMENTS, IN-SITU STEAM/HOT-AIR STRIPPING TECHNOLOGY

    EPA Science Inventory

    This document is an evaluation of the performance of the Toxic Treatments (USA), Inc., (TTUSA) in situ steam/hot-air stripping technology and its applicability as an on-site treatment technique for hazardous waste site soil cleanup of volatile and semivolatile contaminants. Both ...

  15. DETERMINANTS OF HUMAN EXPOSURES TO AIR TOXICS AND ASSOCIATED HEALTH EFFECTS

    EPA Science Inventory

    Individuals are exposed to wide variety of air toxics in various indoor and outdoor microenvironments during the course of their daily activities. Sources of emissions include a wide variety of indoor and outdoor sources, including stationary and mobile sources, building material...

  16. Temporal and modal characterization of DoD source air toxic emission factors: final report

    EPA Science Inventory

    This project tested three, real-/near real-time monitoring techniques to develop air toxic emission factors for Department of Defense (DoD) platform sources. These techniques included: resonance enhanced multi photon ionization time of flight mass spectrometry (REMPI-TOFMS) for o...

  17. CORONA DESTRUCTION: AN INNOVATIVE CONTROL TECHNOLOGY FOR VOCS AND AIR TOXICS

    EPA Science Inventory

    This paper discusses the work and results to date leading to the demonstration of the corona destruction process at pilot scale. The research effort in corona destruction of volatile organic compounds (VOCs) and air toxics has shown significant promise for providing a valuable co...

  18. Evaluation of air toxic emissions from advanced and conventional coal-fired power plants

    SciTech Connect

    Chu, P.; Epstein, M.; Gould, L.; Botros, P.

    1995-12-31

    This paper evaluates the air toxics measurements at three advanced power systems and a base case conventional fossil fuel power plant. The four plants tested include a pressurized fluidized bed combustor, integrated gasification combined cycle, circulating fluidized bed combustor, and a conventional coal-fired plant.

  19. EMISSIONS OF AIR TOXICS FROM A SIMULATED CHARCOAL KILN EQUIPPED WITH AN AFTERBURNER

    EPA Science Inventory

    The report discusses emissions of air toxics from a simulated charcoal kiln equipped with an afterburner. A laboratory-scale simulator was constructed and tested to determine if it could be used to produce charcoal that was similar to that produced in Missouri-type charcoal kilns...

  20. CRITERIA AND AIR TOXIC EMISSIONS FROM IN-USE, LOW EMISSION VEHICLES (LEVS)

    EPA Science Inventory

    The U.S. Environmental Protection Agency implemented a program to identify tailpipe emissions of criteria and air toxic contaminants from in-use, light-duty Low Emission Vehicles (LEVs). EPA recruited twenty-five LEVs in 2002, and measured emissions on a chassis dynamometer usin...

  1. Use of a portable air disinfecting system to remove seeded coliphage in hospital rooms.

    PubMed

    Verhougstraete, Marc; Reynolds, Kelly

    2016-06-01

    Health care-associated infections are a major problem worldwide, and the airborne route is believed to be a contributory source of secondary health care-associated infections. This study examined the efficacy of a portable air disinfecting system to remove seeded coliphage virus from the air in hospitals rooms. Aerosolized coliphage concentrations were not statistically different between treatment and no treatment measurements. However, future research should focus on additional investigations in the patient rooms that incorporate fomite and air testing alongside portable air filtration devices.

  2. The effects of forced air flow and oxygen concentration on flammability, smoke density, and pyrolytic toxicity

    NASA Technical Reports Server (NTRS)

    Sauers, D. G.

    1976-01-01

    The question is posed whether forced air flow should be incorporated into flammability tests as a relevant variable. A test apparatus is described which permits tests to be conducted on small test specimens in a forced flow which is (continuously) variable over flow velocities from zero to 300 feet per minute (1.52 m/s). The effects of air-flow rate and oxygen concentration on flame propagation rate, maximum smoke density, and pyrolytic product toxicity were measured for a single material and were statistically evaluated. Regression analysis was used to graph the resulting relationships. It is concluded that air velocity is an important variable for laboratory flammability testing.

  3. Rapid Removal of Tetrabromobisphenol A by Ozonation in Water: Oxidation Products, Reaction Pathways and Toxicity Assessment.

    PubMed

    Qu, Ruijuan; Feng, Mingbao; Wang, Xinghao; Huang, Qingguo; Lu, Junhe; Wang, Liansheng; Wang, Zunyao

    2015-01-01

    Tetrabromobisphenol A (TBBPA) is one of the most widely used brominated flame retardants and has attracted more and more attention. In this work, the parent TBBPA with an initial concentration of 100 mg/L was completely removed after 6 min of ozonation at pH 8.0, and alkaline conditions favored a more rapid removal than acidic and neutral conditions. The presence of typical anions and humic acid did not significantly affect the degradation of TBBPA. The quenching test using isopropanol indicated that direct ozone oxidation played a dominant role during this process. Seventeen reaction intermediates and products were identified using an electrospray time-of-flight mass spectrometer. Notably, the generation of 2,4,6-tribromophenol was first observed in the degradation process of TBBPA. The evolution of reaction products showed that ozonation is an efficient treatment for removal of both TBBPA and intermediates. Sequential transformation of organic bromine to bromide and bromate was confirmed by ion chromatography analysis. Two primary reaction pathways that involve cleavage of central carbon atom and benzene ring cleavage concomitant with debromination were thus proposed and further justified by calculations of frontier electron densities. Furthermore, the total organic carbon data suggested a low mineralization rate, even after the complete removal of TBBPA. Meanwhile, the acute aqueous toxicity of reaction solutions to Photobacterium Phosphoreum and Daphnia magna was rapidly decreased during ozonation. In addition, no obvious difference in the attenuation of TBBPA was found by ozone oxidation using different water matrices, and the effectiveness in natural waters further demonstrates that ozonation can be adopted as a promising technique to treat TBBPA-contaminated waters. PMID:26430733

  4. Removal of toxic uranium from synthetic nuclear power reactor effluents using uranyl ion imprinted polymer particles.

    PubMed

    Preetha, Chandrika Ravindran; Gladis, Joseph Mary; Rao, Talasila Prasada; Venkateswaran, Gopala

    2006-05-01

    Major quantities of uranium find use as nuclear fuel in nuclear power reactors. In view of the extreme toxicity of uranium and consequent stringent limits fixed by WHO and various national governments, it is essential to remove uranium from nuclear power reactor effluents before discharge into environment. Ion imprinted polymer (IIP) materials have traditionally been used for the recovery of uranium from dilute aqueous solutions prior to detection or from seawater. We now describe the use of IIP materials for selective removal of uranium from a typical synthetic nuclear power reactor effluent. The IIP materials were prepared for uranyl ion (imprint ion) by forming binary salicylaldoxime (SALO) or 4-vinylpyridine (VP) or ternary SALO-VP complexes in 2-methoxyethanol (porogen) and copolymerizing in the presence of styrene (monomer), divinylbenzene (cross-linking monomer), and 2,2'-azobisisobutyronitrile (initiator). The resulting materials were then ground and sieved to obtain unleached polymer particles. Leached IIP particles were obtained by leaching the imprint ions with 6.0 M HCl. Control polymer particles were also prepared analogously without the imprint ion. The IIP particles obtained with ternary complex alone gave quantitative removal of uranyl ion in the pH range 3.5-5.0 with as low as 0.08 g. The retention capacity of uranyl IIP particles was found to be 98.50 mg/g of polymer. The present study successfully demonstrates the feasibility of removing uranyl ions selectively in the range 5 microg - 300 mg present in 500 mL of synthetic nuclear power reactor effluent containing a host of other inorganic species.

  5. Rapid Removal of Tetrabromobisphenol A by Ozonation in Water: Oxidation Products, Reaction Pathways and Toxicity Assessment

    PubMed Central

    Wang, Xinghao; Huang, Qingguo; Lu, Junhe; Wang, Liansheng; Wang, Zunyao

    2015-01-01

    Tetrabromobisphenol A (TBBPA) is one of the most widely used brominated flame retardants and has attracted more and more attention. In this work, the parent TBBPA with an initial concentration of 100 mg/L was completely removed after 6 min of ozonation at pH 8.0, and alkaline conditions favored a more rapid removal than acidic and neutral conditions. The presence of typical anions and humic acid did not significantly affect the degradation of TBBPA. The quenching test using isopropanol indicated that direct ozone oxidation played a dominant role during this process. Seventeen reaction intermediates and products were identified using an electrospray time-of-flight mass spectrometer. Notably, the generation of 2,4,6-tribromophenol was first observed in the degradation process of TBBPA. The evolution of reaction products showed that ozonation is an efficient treatment for removal of both TBBPA and intermediates. Sequential transformation of organic bromine to bromide and bromate was confirmed by ion chromatography analysis. Two primary reaction pathways that involve cleavage of central carbon atom and benzene ring cleavage concomitant with debromination were thus proposed and further justified by calculations of frontier electron densities. Furthermore, the total organic carbon data suggested a low mineralization rate, even after the complete removal of TBBPA. Meanwhile, the acute aqueous toxicity of reaction solutions to Photobacterium Phosphoreum and Daphnia magna was rapidly decreased during ozonation. In addition, no obvious difference in the attenuation of TBBPA was found by ozone oxidation using different water matrices, and the effectiveness in natural waters further demonstrates that ozonation can be adopted as a promising technique to treat TBBPA-contaminated waters. PMID:26430733

  6. RESOLVING FINE SCALE IN AIR TOXICS MODELING AND THE IMPORTANCE OF ITS SUB-GRID VARIABILITY FOR EXPOSURE ESTIMATES

    EPA Science Inventory

    This presentation explains the importance of the fine-scale features for air toxics exposure modeling. The paper presents a new approach to combine local-scale and regional model results for the National Air Toxic Assessment. The technique has been evaluated with a chemical tra...

  7. Heated stainless steel tube for ozone removal in the ambient air measurements of mono- and sesquiterpenes

    NASA Astrophysics Data System (ADS)

    Hellén, H.; Kuronen, P.; Hakola, H.

    2012-09-01

    Heated stainless steel inlets were optimized for the ozone removal and for the measurements of mono- and sesquiterpenes in ambient air. Five different inlets were used with different flows, temperatures and ozone and biogenic volatile organic compound (BVOC) concentrations. Both ozone removal capacities and recoveries of BVOCs were determined. Ozone and BVOCs were flushed through the inlet and recoveries were measured by an ozone monitor and adsorbent tube sampling of BVOCs with subsequent analysis with thermal desorption - gas chromatograph (GC) - mass spectrometer (MS). Recovery tests of BVOCs were conducted both with zero air and with ozone rich air. Inlets were optimized especially for online-GC and adsorbent tube measurements of mono- and sesquiterpenes. The results of this study show that it was possible to remove ozone without removing most VOCs with this set-up. Setting the temperature, stainless steel grade and flow correctly for different inlet lengths was found to have a crucial role. The results show that the ozone removal capacity increases with increasing temperature and inlet length. Stainless steel grade 316 was found to be more efficient than grade 304 with respect to ozone removal. Based only on the ozone removal capacity, the longest possible stainless steel inlet with heating would be the optimum solution. However, the recoveries of studied compounds had to be considered too. Of the tested set-ups, a 3 m inlet (¼ in. grade 304) heated to 120 °C with a flow of 1 or 2 l min-1 was found to give the best results with respect to the ozone removal efficiency and compound recovery. This inlet was removing ozone efficiently for at least 4 months when used for ambient air sampling at a rural forested site with a flow of 1 l min-1 (˜170 m3 of air flushed through the tube). A heated (140 °C) 1 m inlet (¼ in. grade 304 or ⅛ in. grade 316) was able to remove ozone with a constant flow of 0.8-1 l min-1 for about two weeks (˜18 m3 of air) and had

  8. Radon removal from flowing air by a water scrubber

    SciTech Connect

    Blue, T.E.; Jarzemba, M.S.; Fentiman, A.W.; Denison, J.E.

    1994-12-31

    As part of a process that is being developed to vitrify tailings from Belgian Congo ore that is stored in large silos at a former U.S. Department of Energy uranium-processing facility in southwestern Ohio, process off-gas is produced that contains large concentrations of radon gas (on the order of hundreds of thousands of picocuries per litre). To meet U.S. Environmental Protection Agency restrictions, the process off-gas must be stripped of its radon content before it is vented to the atmosphere. It is appropriate to consider a charcoal bed as part of an off-gas treatment system for the removal of radon at the vitrification facility. However, a difficulty arises in incorporating a charcoal bed into an off-gas treatment system at a vitrification facility. That difficulty is that the capability of the charcoal bed to capture and retain radon gas decreases with increasing bed temperature. Thus, it may be necessary to include a water scrubber in the off-gas treatment system to cool the process off-gas before it is passed through the charcoal bed.

  9. Cascade air-stripping system for removal of low and semi-volatile organic contaminants

    SciTech Connect

    Jang, Won.

    1989-01-01

    Many hazardous waste sites have been known to have groundwaters contaminated with low volatile, hazardous compounds such as bromoform 1,1,2,2-tetrachloroethane, 1,2-dibromo-3-chloropropane (DBCP), napthalene, and polychlorinated biphenyls (PCBs). In addition, a large number of public water supplies have been reported to have taste and odor problems in drinking water, which are attributed primarily to naturally occurring compounds, such as 2-methylisoborneol (MIB), geosmin, etc. These classes of compounds have very low Henry's Constant, H{sub c}, in the range of 1 to 50 atm. Air-stripping in countercurrent packed towers is a well accepted treatment process for removing volatile organic chemicals (VOCs) from water. The USEPA has identified packed countercurrent air-stripping as not only the least-cost, but also one of the best available technologies for the removal of VOCs. However, the economic viability of this process is limited to volatile compounds of H{sub c} value greater than SO atm. A novel modification of the conventional countercurrent air-stripping process, introduced as cascade air-stripping was proposed for cost effective removal of these classes of compounds from water and at hazardous waste spill-sites. The main objectives of this study were to demonstrate the concept of cascade air-stripping; to compare cascade air-stripping with conventional air-stripping under identical conditions; and to verify the hypothesis that the cascade system is superior to the conventional system at the pilot and prototype scales. Results of the pilot and prototype study showed that the cascade airstrip ping system was a viable and economical approach to remove low and semi-volatile organic compounds from water. The cascade system consistently showed higher removals than the conventional system for both pilot and prototype scale study.

  10. Removal of antibiotics in wastewater by enzymatic treatment with fungal laccase - Degradation of compounds does not always eliminate toxicity.

    PubMed

    Becker, Dennis; Varela Della Giustina, Saulo; Rodriguez-Mozaz, Sara; Schoevaart, Rob; Barceló, Damià; de Cazes, Matthias; Belleville, Marie-Pierre; Sanchez-Marcano, José; de Gunzburg, Jean; Couillerot, Olivier; Völker, Johannes; Oehlmann, Jörg; Wagner, Martin

    2016-11-01

    In this study, the performance of immobilised laccase (Trametes versicolor) was investigated in combination with the mediator syringaldehyde (SYR) in removing a mixture of 38 antibiotics in an enzymatic membrane reactor (EMR). Antibiotics were spiked in osmosed water at concentrations of 10μg·L(-1) each. Laccase without mediator did not reduce the load of antibiotics significantly. The addition of SYR enhanced the removal: out of the 38 antibiotics, 32 were degraded by >50% after 24h. In addition to chemical analysis, the samples' toxicity was evaluated in two bioassays (a growth inhibition assay and the Microtox assay). Here, the addition of SYR resulted in a time-dependent increase of toxicity in both bioassays. In cooperation with SYR, laccase effectively removes a broad range of antibiotics. However, this enhanced degradation induces unspecific toxicity. If this issue is resolved, enzymatic treatment may be a valuable addition to existing water treatment technologies. PMID:27521787

  11. Evaluating the Spatial Distribution of Toxic Air Contaminants in Multiple Ecosystem Indicators in the Sierra Nevada-Southern Cascades

    NASA Astrophysics Data System (ADS)

    Nanus, L.; Simonich, S. L.; Rocchio, J.; Flanagan, C.

    2013-12-01

    Toxic air contaminants originating from agricultural areas of the Central Valley in California threaten vulnerable sensitive receptors including surface water, vegetation, snow, sediments, fish, and amphibians in the Sierra Nevada-Southern Cascades region. The spatial distribution of toxic air contaminants in different ecosystem indicators depends on variation in atmospheric concentrations and deposition, and variation in air toxics accumulation in ecosystems. The spatial distribution of organic air toxics and mercury at over 330 unique sampling locations and sample types over two decades (1990-2009) in the Sierra Nevada-Southern Cascades region were compiled and maps were developed to further understand spatial patterns and linkages between air toxics deposition and ecological effects. Potential ecosystem impacts in the Sierra Nevada-Southern Cascades region include bioaccumulation of air toxics in both aquatic and terrestrial ecosystems, reproductive disruption, and immune suppression. The most sensitive ecological end points in the region that are affected by bioaccumulation of toxic air contaminants are fish. Mercury was detected in all fish and approximately 6% exceeded human consumption thresholds. Organic air toxics were also detected in fish yielding variable spatial patterns. For amphibians, which are sensitive to pesticide exposure and potential immune suppression, increasing trends in current and historic use pesticides are observed from north to south across the region. In other indicators, such as vegetation, pesticide concentrations in lichen increase with increasing elevation. Current and historic use pesticides and mercury were also observed in snowpack at high elevations in the study area. This study shows spatial patterns in toxic air contaminants, evaluates associated risks to sensitive receptors, and identifies data gaps. Future research on atmospheric modeling and information on sources is needed in order to predict which ecosystems are the

  12. [Steam and air co-injection in removing TCE in 2D-sand box].

    PubMed

    Wang, Ning; Peng, Sheng; Chen, Jia-Jun

    2014-07-01

    Steam and air co-injection is a newly developed and promising soil remediation technique for non-aqueous phase liquids (NAPLs) in vadose zone. In this study, in order to investigate the mechanism of the remediation process, trichloroethylene (TCE) removal using steam and air co-injection was carried out in a 2-dimensional sandbox with different layered sand structures. The results showed that co-injection perfectly improved the "tailing" effect compared to soil vapor extraction (SVE), and the remediation process of steam and air co-injection could be divided into SVE stage, steam strengthening stage and heat penetration stage. Removal ratio of the experiment with scattered contaminant area was higher and removal speed was faster. The removal ratios from the two experiments were 93.5% and 88.2%, and the removal periods were 83.9 min and 90.6 min, respectively. Steam strengthened the heat penetration stage. The temperature transition region was wider in the scattered NAPLs distribution experiment, which reduced the accumulation of TCE. Slight downward movement of TCE was observed in the experiment with TCE initially distributed in a fine sand zone. And such downward movement of TCE reduced the TCE removal ratio.

  13. [Steam and air co-injection in removing TCE in 2D-sand box].

    PubMed

    Wang, Ning; Peng, Sheng; Chen, Jia-Jun

    2014-07-01

    Steam and air co-injection is a newly developed and promising soil remediation technique for non-aqueous phase liquids (NAPLs) in vadose zone. In this study, in order to investigate the mechanism of the remediation process, trichloroethylene (TCE) removal using steam and air co-injection was carried out in a 2-dimensional sandbox with different layered sand structures. The results showed that co-injection perfectly improved the "tailing" effect compared to soil vapor extraction (SVE), and the remediation process of steam and air co-injection could be divided into SVE stage, steam strengthening stage and heat penetration stage. Removal ratio of the experiment with scattered contaminant area was higher and removal speed was faster. The removal ratios from the two experiments were 93.5% and 88.2%, and the removal periods were 83.9 min and 90.6 min, respectively. Steam strengthened the heat penetration stage. The temperature transition region was wider in the scattered NAPLs distribution experiment, which reduced the accumulation of TCE. Slight downward movement of TCE was observed in the experiment with TCE initially distributed in a fine sand zone. And such downward movement of TCE reduced the TCE removal ratio. PMID:25244869

  14. Identification of ambient air sampling and analysis methods for the 189 Title III air toxics

    SciTech Connect

    Mukund, R.; Kelly, T.J.; Gordon, S.M.; Hays, M.J.

    1994-12-31

    The state of development of ambient air measurement methods for the 189 Hazardous Air Pollution (HAPs) in Title 3 of the Clean Air Act Amendments was surveyed. Measurement methods for the HAPs were identified by reviews of established methods, and by literature searches for pertinent research techniques. Methods were segregated by their degree of development into Applicable, Likely, and Potential methods. This survey identified a total of 183 methods, applicable at varying degrees to ambient air measurements of one or more HAPs. As a basis for classifying the HAPs and evaluating the applicability of measurement methods, a survey of a variety of chemical and physical properties of the HAPs was also conducted. The results of both the methods and properties surveys were tabulated for each of the 189 HAP. The current state of development of ambient measurement methods for the 189 HAPs was then assessed from the results of the survey, and recommendations for method development initiatives were developed.

  15. Removal of arsenic from toxic ash after combustion of impregnated wood

    NASA Astrophysics Data System (ADS)

    Ottosen, L. M.; Pedersen, A. J.; Kristensen, I. V.; Ribeiro, A. B.

    2003-05-01

    ln the next ten years the amounts of waste wood impregnated with Cu, Cr and As (CCA) is expected to increase dramatically. Mixed with municipal solid waste for incineration the wood constitutes a problem because As emission is not hindered through common flue gas treatment. Furthermore the ashes will contain higher concentrations of Cu, Cr and As. In different countries initiatives has been taken or are implemented to sort the impregnated wood from other waste and handle the wood separately. This handling can involve combustion in special plants. This paper deals with electrodialytic treatment of ash from combustion of CCA treated wood. The total concentrations in the ash were very high: 69gCu/kg, 62gCr/kg and 35gAs/kg. A SEM/EDX analysis showed that Cr was mainly build into the matrix structure of the ash. Cu, too, but some Cu was also precipitated on the surface of the particles. As, on the other hand, was only found associated with Ca and thus probably in a soluble form. As is the main problem of the ash due to the high toxicity and mobility and thus the treatment aims at removing this element. It was shown that during 5 days of electrodialytic treatment 92% As could be removed.

  16. Phytoremediation of chlorpyrifos in aqueous system by riverine macrophyte, Acorus calamus: toxicity and removal rate.

    PubMed

    Wang, Qinghai; Li, Cui; Zheng, Ruilun; Que, Xiaoe

    2016-08-01

    The potential of Acorus calamus to remove chlorpyrifos from water was assessed under laboratory conditions. Toxic effects of the insecticide in A. calamus were evaluated using pulse-amplitude modulated chlorophyll fluorescence techniques as well. At exposure concentrations above 8 mg L(-1), A. calamus showed obvious phytotoxic symptom with significant reduction in quantum efficiency of PSII (ΦPSII) and photochemical quenching coefficient (qP) in 20-day test; the inhibition of maximal quantum efficiency of PSII (Fv/Fm) was accompanied by a significant rise in initial chlorophyll fluorescence (Fo) within 15-day exposures. Fv/Fm and Fo recover to the normal level after 20-day exposure. The reduced removal rate to chlorpyrifos was observed with increase of initial chlorpyrifos concentrations. At application levels of 1, 2, and 4 mg L(-1), the disappearance rate of chlorpyrifos in the hydroponic system with plants was significantly greater than that without plants during the 20-day test periods. Chlorpyrifos was taken up from medium and transferred to above ground tissues by the plant and significant amounts of chlorpyrifos accumulated in plant tissues. The result indicated that A. calamus can promote the disappearance of chlorpyrifos from water and may be used for phytoremediation of water contaminated with a relatively low concentration of chlorpyrifos insecticide (<4 mg L(-1)). PMID:27154841

  17. Optical nanosphere sensor based on shell-by-shell fabrication for removal of toxic metals from human blood.

    PubMed

    El-Safty, S A; Abdellatef, S; Ismael, M; Shahat, A

    2013-06-01

    Because toxic heavy metals tend to bioaccumulate, they represent a substantial human health hazard. Various methods are used to identify and quantify toxic metals in biological tissues and environment fluids, but a simple, rapid, and inexpensive system has yet to be developed. To reduce the necessity for instrument-dependent analysis, we developed a single, pH-dependent, nanosphere (NS) sensor for naked-eye detection and removal of toxic metal ions from drinking water and physiological systems (i.e., blood). The design platform for the optical NS sensor is composed of double mesoporous core-shell silica NSs fabricated by one-pot, template-guided synthesis with anionic surfactant. The dense shell-by-shell NS construction generated a unique hierarchical NS sensor with a hollow cage interior to enable accessibility for continuous monitoring of several different toxic metal ions and efficient multi-ion sensing and removal capabilities with respect to reversibility, longevity, selectivity, and signal stability. Here, we examined the application of the NS sensor for the removal of toxic metals (e.g., lead ions from a physiological system, such as human blood). The findings show that this sensor design has potential for the rapid screening of blood lead levels so that the effects of lead toxicity can be avoided.

  18. Optical nanosphere sensor based on shell-by-shell fabrication for removal of toxic metals from human blood.

    PubMed

    El-Safty, S A; Abdellatef, S; Ismael, M; Shahat, A

    2013-06-01

    Because toxic heavy metals tend to bioaccumulate, they represent a substantial human health hazard. Various methods are used to identify and quantify toxic metals in biological tissues and environment fluids, but a simple, rapid, and inexpensive system has yet to be developed. To reduce the necessity for instrument-dependent analysis, we developed a single, pH-dependent, nanosphere (NS) sensor for naked-eye detection and removal of toxic metal ions from drinking water and physiological systems (i.e., blood). The design platform for the optical NS sensor is composed of double mesoporous core-shell silica NSs fabricated by one-pot, template-guided synthesis with anionic surfactant. The dense shell-by-shell NS construction generated a unique hierarchical NS sensor with a hollow cage interior to enable accessibility for continuous monitoring of several different toxic metal ions and efficient multi-ion sensing and removal capabilities with respect to reversibility, longevity, selectivity, and signal stability. Here, we examined the application of the NS sensor for the removal of toxic metals (e.g., lead ions from a physiological system, such as human blood). The findings show that this sensor design has potential for the rapid screening of blood lead levels so that the effects of lead toxicity can be avoided. PMID:23307510

  19. The safe removal of frozen air from the annulus of an LH2 storage tank

    NASA Astrophysics Data System (ADS)

    Krenn, A.; Starr, S.; Youngquist, R.; Nurge, M.; Sass, J.; Fesmire, J.; Cariker, C.; Bhattacharya, A.

    2015-12-01

    Large Liquid Hydrogen (LH2) storage tanks are vital infrastructure for NASA. Eventually, air may leak into the evacuated and perlite filled annular region of these tanks. Although the vacuum level is monitored in this region, the extremely cold temperature causes all but the helium and neon constituents of air to freeze. A small, often unnoticeable pressure rise is the result. As the leak persists, the quantity of frozen air increases, as does the thermal conductivity of the insulation system. Consequently, a notable increase in commodity boil-off is often the first indicator of an air leak. Severe damage can result from normal draining of the tank. The warming air will sublimate which will cause a pressure rise in the annulus. When the pressure increases above the triple point, the frozen air will begin to melt and migrate downward. Collection of liquid air on the carbon steel outer shell may chill it below its ductility range, resulting in fracture. In order to avoid a structural failure, as described above, a method for the safe removal of frozen air is needed. A thermal model of the storage tank has been created using SINDA/FLUINT modelling software. Experimental work is progressing in an attempt to characterize the thermal conductivity of a perlite/frozen nitrogen mixture. A statistical mechanics model is being developed in parallel for comparison to experimental work. The thermal model will be updated using the experimental/statistical mechanical data, and used to simulate potential removal scenarios. This paper will address methodologies and analysis techniques for evaluation of two proposed air removal methods.

  20. The Safe Removal of Frozen Air from the Annulus of an LH2 Storage Tank

    NASA Technical Reports Server (NTRS)

    Krenn, A.; Starr, S.; Youngquist, R.; Nurge, M.; Sass, J.; Fesmire, J.; Cariker, C.; Bhattacharya, A.

    2015-01-01

    Large Liquid Hydrogen (LH2) storage tanks are vital infrastructure for NASA. Eventually, air may leak into the evacuated and perlite filled annular region of these tanks. Although the vacuum level is monitored in this region, the extremely cold temperature causes all but the helium and neon constituents of air to freeze. A small, often unnoticeable pressure rise is the result. As the leak persists, the quantity of frozen air increases, as does the thermal conductivity of the insulation system. Consequently, a notable increase in commodity boil-off is often the first indicator of an air leak. Severe damage can result from normal draining of the tank. The warming air will sublimate which will cause a pressure rise in the annulus. When the pressure increases above the triple point, the frozen air will begin to melt and migrate downward. Collection of liquid air on the carbon steel outer shell may chill it below its ductility range, resulting in fracture. In order to avoid a structural failure, as described above, a method for the safe removal of frozen air is needed. A thermal model of the storage tank has been created using SINDA/FLUINT modeling software. Experimental work is progressing in an attempt to characterize the thermal conductivity of a perlite/frozen nitrogen mixture. A statistical mechanics model is being developed in parallel for comparison to experimental work. The thermal model will be updated using the experimental/statistical mechanical data, and used to simulate potential removal scenarios. This paper will address methodologies and analysis techniques for evaluation of two proposed air removal methods.

  1. Factors affecting the removal of ammonia from air on carbonaceous materials: Investigation of reactive adsorption mechanism

    NASA Astrophysics Data System (ADS)

    Petit, Camille

    Air pollution related to the release of industrial toxic gases, represents one of the main concerns of our modern world owing to its detrimental effect on the environment. To tackle this growing issue, efficient ways to reduce/control the release of pollutants are required. Adsorption of gases on porous materials appears as a potential solution. However, the physisorption of small molecules of gases such as ammonia is limited at ambient conditions. For their removal, adsorbents providing strong adsorption forces must be used/developed. In this study, new carbon-based materials are prepared and tested for ammonia adsorption at ambient conditions. Characterization of the adsorbents' texture and surface chemistry is performed before and after exposure to ammonia to identify the features responsible for high adsorption capacity and for controlling the mechanisms of retention. The characterization techniques include: nitrogen adsorption, thermal analysis, potentiometric titration, FT-IR spectroscopy, X-ray diffraction, Energy Dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy and Electron Microscopy. The results obtained indicate that ammonia removal is governed by the adsorbent's surface chemistry. On the contrary, porosity (and thus physisorption) plays a secondary role in this process, unless strong dispersive forces are provided by the adsorbent. The surface chemistry features responsible for the enhanced ammonia adsorption include the presence of oxygen-(carboxyl, hydroxyl, epoxy) and sulfur- (sulfonic) containing groups. Metallic species improve the breakthrough capacity as well as they lead to the formation of Lewis acid-base interactions, hydrogen-bonding or complexation. In addition to the latter three mechanisms, ammonia is retained on the adsorbent surface via Bronsted acid-base interactions or via specific reactions with the adsorbent's functionalities leading to the incorporation of ammonia into the adsorbent's matrix. Another mechanism

  2. Removal efficiencies of PCDDs/PCDFs by air pollution control devices in municipal solid waste incinerators.

    PubMed

    Kim, S C; Jeon, S H; Jung, I R; Kim, K H; Kwon, M H; Kim, J H; Yi, J H; Kim, S J; You, J C; Jung, D H

    2001-01-01

    Removal efficiencies of polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans (PCDDs/PCDFs) by air pollution control devices (APCDs) in the commercial-scale municipal solid waste (MSW) incinerators with a capacity of above 200 ton/day were evaluated. The removal efficiencies of PCDDs/PCDFs were up to 95% when the activated carbon (AC) was injected in front of electrostatic precipitator (EP). Spray dryer absorber/bag filter (SDA/BF) had high removal efficiency (99%)) of PCDDs/PCDFs when a mixture of lime and AC was sprayed into the SDA. When the AC was not added in scrubbing solution, the whole congeners of PCDDs/PCDFs were enriched in the wet scrubber (WS) with negative removal efficiencies of -25% to -5731%. Discharge of PCDDs/PCDFs was decreased with increasing the proportions of AC added in scrubbing solution. Selective catalytic reduction (SCR) system had the removal efficiencies of up to 93% during the test operation.

  3. Air toxics concentrations, source identification, and health risks: An air pollution hot spot in southwest Memphis, TN

    NASA Astrophysics Data System (ADS)

    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.

  4. Segregation and black/white differences in exposure to air toxics in 1990.

    PubMed Central

    Lopez, Russ

    2002-01-01

    I examined non-Hispanic Black and non-Hispanic White differences in exposure to noncriteria air pollutants in 44 U.S. Census Bureau-defined metropolitan areas with populations greater than one million, using data on air toxics concentrations prepared for the U.S. Environmental Protection Agency as part of its Cumulative Exposure Project combined with U.S. census data. I measured differences in exposure to air toxics through the calculation of a net difference score, which is a statistical measure used in income inequality analysis to measure inequality over the whole range of exposures. The scores ranged from 11.52 to 83.60. In every metropolitan area, non-Hispanic Blacks are more likely than non-Hispanic Whites to be living in tracts with higher total modeled air toxics concentrations. To assess potential reasons for such a wide variation in exposure differences, I performed a multiple regression analysis with the net difference score as the dependent variable. Independent variables initially included were as follows: the dissimilarity index (to measure segregation), Black poverty/White poverty (to control for Black/White economic differences), population density and percentage of persons traveling to work who drive to work (alone and in car pools), and percentage of workforce employed in manufacturing (factors affecting air quality). After an initial analysis I eliminated from the model the measures of density and the persons driving to work because they were statistically insignificant, they did not add to the predictive power of the model, and their deletion did not affect the other variables. The final model had an R(2) of 0.56. Increased segregation is associated with increased disparity in potential exposure to air pollution. PMID:11929740

  5. A model to predict the removal of oxygen from air using a zirconia solid electrolyte membrane

    NASA Technical Reports Server (NTRS)

    Marner, W. J.; Suitor, J. W.; Glazer, C. R.

    1988-01-01

    A finite difference mathematical model has been developed to predict the removal of oxygen from air using a zirconia separation cell. The model predicts the electrical and mass transfer processes in circular disk cells with either axial or radial current flow in the electrodes and in tubular cells with axial current flow in the electrodes. Representative results are presented and discussed.

  6. CHEMICAL REMOVAL OF BIOMASS FROM WASTE AIR BIOTRICKLING FILTERS: SCREENING CHEMICALS OF POTENTIAL INTEREST. (R825392)

    EPA Science Inventory

    A protocol was developed to rapidly assess the efficiency of chemical washing for the removal of excess biomass from biotrickling filters for waste air treatment. Although the experiment was performed on a small scale, conditions were chosen to simulate application in full-scale ...

  7. 77 FR 25953 - Approval and Promulgation of Air Quality Implementation Plans; Maryland; Removal of the 1980...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-02

    ... AGENCY 40 CFR Part 52 Approval and Promulgation of Air Quality Implementation Plans; Maryland; Removal of the 1980 Consent Order for the Maryland Slag Company AGENCY: Environmental Protection Agency (EPA... submitted by the Maryland Department of Environment to revise the Maryland State Implementation Plan...

  8. Calibration of the Langley 16-foot transonic tunnel with test section air removal

    NASA Technical Reports Server (NTRS)

    Corson, B. W., Jr.; Runckel, J. F.; Igoe, W. B.

    1974-01-01

    The Langley 16-foot transonic tunnel with test section air removal (plenum suction) was calibrated to a Mach number of 1.3. The results of the calibration, including the effects of slot shape modifications, test section wall divergence, and water vapor condensation, are presented. A complete description of the wind tunnel and its auxiliary equipment is included.

  9. EVALUATION OF TRICKLE-BED AIR BIOFILTER PERFORMANCE FOR STYRENE REMOVAL

    EPA Science Inventory

    A pilot-scale trickle-bed air biofilter (TBAB) was evaluated for the removal of styrene from a waste gas stream. Six-millimeter (6 mm) Celite pellets (R-635) were used as the biological attachment medium. The operating parameters considered in the study included the styrene vol...

  10. Steam and air co-injection in removing residual TCE in unsaturated layered sandy porous media.

    PubMed

    Peng, Sheng; Wang, Ning; Chen, Jiajun

    2013-10-01

    Steam and air co-injection is a promising technique for volatile and semi-volatile organic contaminant remediation in heterogeneous porous media. In this study, removal of trichloroethene (TCE) with steam-air co-injection was investigated through a series of 2D sandbox experiments with different layered sand structures, and through numerical simulations. The results show that a layered structure with coarse sand, in which steam and air convection are relatively rapid, resulted in a higher removal rate and a larger removal ratio than those observed in an experiment using finer sand; however, the difference was not significant, and the removal ratios from three experiments ranged from 85% to 94%. Slight downward movement of TCE was observed for Experiment 1 (TCE initially in a fine sand zone encased in a coarse sand), while no such movement was observed for Experiment 2 (TCE initially in two fine sand layers encased in a coarse sand) or 3 (TCE initially in a silty sand zone encased in a coarse sand). Simulations show accumulation of TCE at the interface of the layered sands, which indicates a capillary barrier effect in restraining the downward movement of TCE. This effect is illustrated further by a numerical experiment with homogeneous coarse sand, in which continuous downward TCE movement to the bottom of the sandbox was simulated. Another numerical experiment with higher water saturation was also conducted. The results illustrate a complicated influence of water saturation on TCE removal in a layered sand structure.

  11. Can ornamental potted plants remove volatile organic compounds from indoor air? A review.

    PubMed

    Dela Cruz, Majbrit; Christensen, Jan H; Thomsen, Jane Dyrhauge; Müller, Renate

    2014-12-01

    Volatile organic compounds (VOCs) are found in indoor air, and many of these can affect human health (e.g. formaldehyde and benzene are carcinogenic). Plants affect the levels of VOCs in indoor environments, thus they represent a potential green solution for improving indoor air quality that at the same time can improve human health. This article reviews scientific studies of plants' ability to remove VOCs from indoor air. The focus of the review is on pathways of VOC removal by the plants and factors affecting the efficiency and rate of VOC removal by plants. Laboratory based studies indicate that plant induced removal of VOCs is a combination of direct (e.g. absorption) and indirect (e.g. biotransformation by microorganisms) mechanisms. They also demonstrate that plants' rate of reducing the level of VOCs is influenced by a number of factors such as plant species, light intensity and VOC concentration. For instance, an increase in light intensity has in some studies been shown to lead to an increase in removal of a pollutant. Studies conducted in real-life settings such as offices and homes are few and show mixed results.

  12. Evaluation of a possible association of urban air toxics and asthma.

    PubMed Central

    Leikauf, G D; Kline, S; Albert, R E; Baxter, C S; Bernstein, D I; Buncher, C R

    1995-01-01

    The prevalence of asthma, measured either as the frequency of hospital admissions or number of deaths attributed to asthma, has increased over the last 15 to 20 years. Rapid increases in disease prevalence are more likely to be attributable to environmental than genetic factors. Inferring from past associations between air pollution and asthma, it is feasible that changes in the ambient environment could contribute to this increase in morbidity and mortality. Scientific evaluation of the links between air pollution and the exacerbation of asthma is incomplete, however. Currently, criteria pollutants [SOx, NOx, O3, CO, Pb, particulate matter (PM10)] and other risk factors (exposure to environmental tobacco smoke, volatile organic compounds, etc.) are constantly being evaluated as to their possible contributions to this situation. Data from these studies suggest that increases in respiratory disease are associated with exposures to ambient concentrations of particulate and gaseous pollutants. Similarly, exposure to environmental tobacco smoke, also a mixture of particulate and gaseous air toxics, has been associated with an increase in asthma among children. In addition, current associations of adverse health effects with existing pollution measurements are often noted at concentrations below those that produce effects in controlled animal and human exposures to each pollutant alone. These findings imply that adverse responses are augmented when persons are exposed to irritant mixtures of particles and gases and that current measurements of air pollution are, in part, indirect in that the concentrations of criteria pollutants are acting as surrogates of our exposure to a complex mixture. Other irritant air pollutants, including certain urban air toxics, are associated with asthma in occupational settings and may interact with criteria pollutants in ambient air to exacerbate asthma. An evaluation of dose-response information for urban air toxics and biological

  13. MODELING AIR TOXICS AND PM 2.5 CONCENTRATION FIELDS AS A MEANS FOR FACILITATING HUMAN EXPOSURE ASSESSMENTS

    EPA Science Inventory

    The capability of the US EPA Models-3/Community Multiscale Air Quality (CMAQ) modeling system is extended to provide gridded ambient air quality concentration fields at fine scales. These fields will drive human exposure to air toxics and fine particulate matter (PM2.5) models...

  14. Air toxics in coal: Distribution and abundance of selected trace elements in the Powder River Basin

    SciTech Connect

    Crowley, S.S.; Stanton, R.W.

    1994-12-31

    The 1990 Clean Air Act Amendments identified 12 potentially toxic elements, called ``air toxics,`` that may be released during the combustion of coal. The elements identified in the amendments are As, Be, Cd, Cr, Co, Hg, Mn, Ni, Pb, Sb, Se, and U (radionuclides). In this study, the distribution and concentration of these elements were examined, on a whole-coal basis, in samples from two cores of the Wyodak-Anderson coal bed (Paleocene, Tongue River Member of the Fort Union Formation), in the Powder River Basin of Wyoming. The distribution of these elements in the Wyodak-Anderson coal bed is also compared to the distribution of the same elements in a correlative coal bed, the Anderson-Dietz 1 coal bed in the Powder River Basin of Montana.

  15. Flue gas treatment for SO2 removal with air-sparged hydrocyclone technology.

    PubMed

    Bokotko, Romuald P; Hupka, Jan; Miller, Jan D

    2005-02-15

    Laboratory results from an initial study on the removal of SO2 from gas mixtures are reported using air-sparged hydrocyclone (ASH) technology. Tap water and alkaline solutions were used for absorption, and the influence of gas flow rate, water flow rate, and length of the ASH unit were investigated. The research results indicate thatthe air-sparged hydrocyclone can be used as a highly efficient absorber for SO2 emissions. The ASH allows for 97% SO2 removal using water alone for sulfur dioxide content in the gas phase of 5 g/m3. All SO2 is removed in weakly alkaline solution (0.01 mol NaOH/dm3).

  16. Economic evaluation of air stripping to remove volatile organic compounds from water. Final report

    SciTech Connect

    Zaghloul, H.H.; Ball, R.O.; Maloney, S.W.

    1987-12-01

    This report documents the results of a study conducted to provide a basis for estimating the costs of installing and using air stripping to remove volatile organic compounds (VOCs) from water. The air-stripping technology was found to be a very economical and efficient method for contaminant removal. The technology is simple, relatively inexpensive to install, and has low labor and maintenance requirements. VOC removal rates range from 90 to 99.99%. Estimated costs, in terms of percentage of total production costs, were found to be 40% for capital costs, 50% for operational costs, and 10% for maintenance costs, according to literature sources. Results of a survey conducted during this study generally agree with these percentages, except that maintenance costs reported on the survey were lower due to the highly automated nature of new installations.

  17. VOCs removal from industrial wastewater via air stripping - an operating experience

    SciTech Connect

    Ansari, M.A.; Hsieh, D.T.

    1996-12-31

    This paper presents design criteria and operating experience of an air stripping unit installed to remove volatile organic compounds (VOCs) from process wastewater in a phenol and acetone manufacturing facility. The unit also removes contaminants from the ground water within the plant for OCSPF compliance. The desorbed hydrocarbon are destroyed in a thermal oxidizer. Air stripping is a fast, efficient, and economical approach to treating waste streams with varying characteristics such as contaminant strength and flows. Evaluation of some of the alternatives to an air stripping process is also discussed. The system was installed in Allied Signal`s chemical manufacturing in Philadelphia, PA., in 1991 and has been operating satisfactorily. Some of the post start-up problems and their solutions, and necessary process modification are also discussed.

  18. Toxic metals in Venics lagoon sediments: Model, observation, an possible removal

    SciTech Connect

    Basu, A.; Molinaroli, E.

    1994-11-01

    We have modeled the distribution of nine toxic metals in the surface sediments from 163 stations in the Venice lagoon using published data. Three entrances from the Adriatic Sea control the circulation in the lagoon and divide it into three basins. We assume, for purposes of modeling, that Porto Marghera at the head of the Industrial Zone area is the single source of toxic metals in the Venice lagoon. In a standing body of lagoon water, concentration of pollutants at distance x from the source (C{sub 0}) may be given by C=C{sub 0}e{sup -kx} where k is the rate constant of dispersal. We calculated k empirically using concentrations at the source, and those farthest from it, that is the end points of the lagoon. Average k values (ppm/km) in the lagoon are: Zn 0.165, Cd 0.116, Hg 0.110, Cu 0.105, Co 0.072, Pb 0.058, Ni 0.008, Cr (0.011) and Fe (0.018 percent/km), and they have complex distributions. Given the k values, concentration at source (C{sub 0}), and the distance x of any point in the lagoon from the source, we have calculated the model concentrations of the nine metals at each sampling station. Tides, currents, floor morphology, additional sources, and continued dumping perturb model distributions causing anomalies (observed minus model concentrations). Positive anomalies are found near the source, where continued dumping perturbs initial boundary conditions, and in areas of sluggish circulation. Negative anomalies are found in areas with strong currents that may flush sediments out of the lagoon. We have thus identified areas in the lagoon where higher rate of sediment removal and exchange may lesson pollution. 41 refs., 4 figs., 3 tabs.

  19. Treatment of tunnel wash waters--experiments with organic sorbent materials. Part II: Removal of toxic metals.

    PubMed

    Paruch, Adam M; Roseth, Roger

    2008-01-01

    In the first part of the article, the column and the bag experiments concerning removal of polycyclic aromatic hydrocarbons (PAHs) and nonpolar oil (NPO) from tunnel wash waters using organic sorbent materials have been described. This part presents the results of removal of toxic metals. The metals of concern (Al, As, Cd, Cr, Cu, Fe, Pb, Mo, Ni, and Zn) were selected based on the priority toxicant pollutants defined in surface water quality criteria. Concentrations of these metals in the collected effluents varied more than the concentrations of PAHs and NPO, and thus only metal contents were considered for statistical analyses. These analyses determined significant differences (P < 0.05, P < 0.01, and P < 0.001) between the mean metal concentrations in the column effluents and those in applied wash water of road tunnel. The results obtained during both experiments revealed that the organic sorbents, and in particular their combination, removed toxic metals more effectively from wash water of road tunnel than from wash water of tunnel electrostatic filters. Among the investigated toxicants, Al and Fe showed the highest levels of reduction in the column experiment, 99.7% and 99.6%, respectively. The lowest reduction levels of 66.0% and 76.2% were found for Pb and Mo, respectively. The results of the bag experiment showed that even one day treatment of wash waters from tunnel electrostatic filters could reduce concentration of some toxicants by more than 70% (Al and Fe) and 80% (Cu).

  20. Removal of cadmium by Lactobacillus kefir as a protective tool against toxicity.

    PubMed

    Gerbino, Esteban; Carasi, Paula; Tymczyszyn, E Elizabeth; Gómez-Zavaglia, Andrea

    2014-08-01

    The aim of this work was to evaluate the capacity of Lactobacillus kefir strains to remove cadmium cations and protect eukaryotic cells from cadmium toxicity. Lb. kefir CIDCA 8348 and JCM 5818 were grown in a 1/2 dilution of MRS broth supplemented with Cd(NO3)2 ranging 0 to 1 mM. Growth kinetics were followed during 76 h at 30 °C by registering optical density at 600 nm every 4-10 h. The accumulated concentration of cadmium was determined on cultures in the stationary phase by atomic absorption. The viability of a human hepatoma cell line (HepG2) upon exposure to (a) free cadmium and (b) cadmium previously incubated with Lb. kefir strains was evaluated by determining the mitochondrial dehydrogenase activity. Lb. kefir strains were able to grow and tolerate concentrations of cadmium cations up to 1 mM. The addition of cadmium to the culture medium increased the lag time in all the concentrations used. However, a decrease of the total biomass (maximum Absorbance) was observed only at concentrations above 0.0012 and 0.0011 mM for strains CIDCA 8348 and JCM 5818, respectively. Shorter and rounder lactobacilli were observed in both strains upon microscopic observations. Moreover, dark precipitates compatible with intracellular precipitation of cadmium were observed in the cytoplasm of both strains. The ability of Lb. kefir to protect eukaryotic cells cultures from cadmium toxicity was analysed using HepG2 cells lines. Concentrations of cadmium greater than 3×10(-3) mM strongly decreased the viability of HepG2 cells. However, when the eukaryotic cells were exposed to cadmium pre-incubated 1 h with Lb. kefir the toxicity of cadmium was considerably lower, Lb. kefir JCM 5818 being more efficient. The high tolerance and binding capacity of Lb. kefir strains to cadmium concentrations largely exceeding the tolerated weekly intake (TWI) of cadmium for food (2.5 μg per kg of body weight) and water (3 μg/l) addressed to human consumption, is an important added value when

  1. Evaluation of a low-cost adsorbent for removal of toxic metal ions from wastewater of an electroplating factory.

    PubMed

    Sousa, Francisco W; Sousa, Marcelo James; Oliveira, Isadora R N; Oliveira, André G; Cavalcante, Rivelino M; Fechine, Pierre B A; Neto, Vicente O S; de Keukeleire, Denis; Nascimento, Ronaldo F

    2009-08-01

    In this study, sugar cane residue or bagasse was used for removal of toxic metal ions from wastewater of an electroplating factory located in northeast Brazil. Prior acid treatment increased the adsorption efficacies in batch wise experiments. The microstructure of the material before and after the treatment was investigated by X-ray diffraction, infrared spectroscopy and scanning electron microscopy. Column operations showed that removals of Cu(2+), Ni(2+) and Zn(2+) from wastewater (in the absence of cyanide) were 95.5%, 96.3.0%, and 97.1%, respectively. Regeneration of the adsorbent obtained in acid indicated that the efficiencies decreased only after the fourth cycle of re-use. Acid-treated sugar cane bagasse can be considered a viable alternative to common methods to remove toxic metal ions from aqueous effluents of electroplating industries.

  2. Spatial variations of particulate matter and air toxics in communities adjacent to the Port of Oakland.

    PubMed

    Fujita, Eric M; Campbell, David E; Arnott, W Patrick; Lau, Virginia; Martien, Philip T

    2013-12-01

    The Bay Area Air Quality Management District (BAAQMD) sponsored the West Oakland Monitoring Study (WOMS) to provide supplemental air quality monitoring that will be used by the BAAQMD to evaluate local-scale dispersion modeling of diesel emissions and other toxic air contaminants for the area within and around the Port of Oakland. The WOMS was conducted during two seasonal periods of 4 weeks in summer 2009 and winter 2009/2010. Monitoring data showed spatial patterns of pollutant concentrations that were generally consistent with proximity to vehicle traffic. Concentrations of directly emitted pollutants were highest on heavily traveled roads with consistently lower concentrations away from the roadways. Pollutants that have higher emission rates from diesel trucks (nitric oxide, black carbon) tended to exhibit sharper gradients than pollutants that are largely associated with gasoline vehicles, such as carbon monoxide and volatile organic compounds, including benzene, toluene, ethylbenzene, and xylenes (BTEX). BTEX concentrations in West Oakland were similar to those measured at the three air toxics monitoring network sites in the Bay Area (San Francisco, Fremont, and San Jose). Aldehyde levels were higher in Fremont and San Jose than in West Oakland, reflecting greater contributions from photo-oxidation of hydrocarbons downwind of the Bay Area. A 2005 modeling-based health risk assessment of diesel particulate matter concentrations is consistent with aerosol carbon concentrations measured during the WOMS after adjusting for recent mitigation measures and improved estimates of heavy-duty truck traffic volumes.

  3. Removal of toxic indigo blue with integrated biomaterials of sodium carboxymethyl cellulose and chitosan.

    PubMed

    Zhu, Xinyi; Bao, Liping; Wei, Yong; Ma, Jiangquan; Kong, Yong

    2016-10-01

    Sodium carboxymethyl cellulose (NaCMC) and chitosan (CS) are successfully combined via amidation, and the obtained product, CMC-CS-A, is used for the adsorption of toxic indigo blue (IB) for the first time. The results of control experiments indicate that the adsorption performance of CMC-CS-A is superior to that of NaCMC, CS, and the composites of NaCMC and CS integrated via electrostatic attractions (CMC-CS-E), which can be attributed to the unique interconnected porous network structure of the as-prepared CMC-CS-A. The mass fraction of CS in the CMC-CS-A is also investigated to achieve the best adsorption of IB, and it reveals that satisfactory removal of IB can be achieved at the CMC-CS-A (50wt%). Important parameters such as contact time, temperature and initial concentration are discussed in detail in this work. Finally, adsorption isotherms and adsorption kinetics are investigated and compared by using classic models, and the results indicate that the adsorption fits well with the Langmuir isotherm model and the pseudo-second-order kinetic model. It opens a new avenue for the effective and convenient treatment of textile wastewater with integrated natural biopolymers. PMID:27246379

  4. Removal of heavy metals from toxic wastes using composite polypyrrole films

    SciTech Connect

    Hepel, M.; Stephenson, R.

    1995-12-31

    In this paper, we will present a new method of removal of heavy metals such as Pb{sup 2+}, Ni{sup +2}, Ca{sup +2}, Cd{sup +2} from contaminated waters or toxic wastes by using conductive polymer films. Procedures used in the preparation of composite polypyrrole films will be discussed. These films, when electrodeposited on the electrode, are capable of fast and efficient incorporation of any heavy metals which exist in aqueous solution in the form of cations by applying suitable potential step. To track the incorporation or release of heavy metals from the film, the Electrochemical Quartz Crystal Microbalance (EQCM) has been used. The EQCM technique, as a sensitive piezoelectric sensor offers a direct and {open_quotes}in-situ{close_quotes} measurement of ion selectivity and ion dynamics in these conductive polymer films. The selectivity coefficients for a variety of heavy metals versus Na{sup +} were evaluated. An electrochemical post-treatment step restores the incorporation capacity of the composite polymer for heavy metals to its initial state.

  5. Assessing different mechanisms of toxicity in mountaintop removal/valley fill coal mining-affected watershed samples using Caenorhabditis elegans.

    PubMed

    Turner, Elena A; Kroeger, Gretchen L; Arnold, Mariah C; Thornton, B Lila; Di Giulio, Richard T; Meyer, Joel N

    2013-01-01

    Mountaintop removal-valley fill coal mining has been associated with a variety of impacts on ecosystem and human health, in particular reductions in the biodiversity of receiving streams. However, effluents emerging from valley fills contain a complex mixture of chemicals including metals, metalloids, and salts, and it is not clear which of these are the most important drivers of toxicity. We found that streamwater and sediment samples collected from mine-impacted streams of the Upper Mud River in West Virginia inhibited the growth of the nematode Caenorhabditis elegans. Next, we took advantage of genetic and transgenic tools available in this model organism to test the hypotheses that the toxicity could be attributed to metals, selenium, oxidative stress, or osmotic stress. Our results indicate that in general, the toxicity of streamwater to C. elegans was attributable to osmotic stress, while the toxicity of sediments resulted mostly from metals or metalloids.

  6. Assessing Different Mechanisms of Toxicity in Mountaintop Removal/Valley Fill Coal Mining-Affected Watershed Samples Using Caenorhabditis elegans

    PubMed Central

    Turner, Elena A.; Kroeger, Gretchen L.; Arnold, Mariah C.; Thornton, B. Lila; Di Giulio, Richard T.; Meyer, Joel N.

    2013-01-01

    Mountaintop removal-valley fill coal mining has been associated with a variety of impacts on ecosystem and human health, in particular reductions in the biodiversity of receiving streams. However, effluents emerging from valley fills contain a complex mixture of chemicals including metals, metalloids, and salts, and it is not clear which of these are the most important drivers of toxicity. We found that streamwater and sediment samples collected from mine-impacted streams of the Upper Mud River in West Virginia inhibited the growth of the nematode Caenorhabditis elegans. Next, we took advantage of genetic and transgenic tools available in this model organism to test the hypotheses that the toxicity could be attributed to metals, selenium, oxidative stress, or osmotic stress. Our results indicate that in general, the toxicity of streamwater to C. elegans was attributable to osmotic stress, while the toxicity of sediments resulted mostly from metals or metalloids. PMID:24066176

  7. Uptake of toluene and ethylbenzene by plants: removal of volatile indoor air contaminants.

    PubMed

    Sriprapat, Wararat; Suksabye, Parinda; Areephak, Sirintip; Klantup, Polawat; Waraha, Atcharaphan; Sawattan, Anuchit; Thiravetyan, Paitip

    2014-04-01

    Air borne uptake of toluene and ethylbenzene by twelve plant species was examined. Of the twelve plant species examined, the highest toluene removal was found in Sansevieria trifasciata, while the ethylbenzene removal from air was with Chlorophytum comosum. Toluene and ethylbenzene can penetrate the plant׳s cuticle. However, the removal rates do not appear to be correlated with numbers of stomata per plant. It was found that wax of S. trifasciata and Sansevieria hyacinthoides had greater absorption of toluene and ethylbenzene, and it contained high hexadecanoic acid. Hexadecanoic acid might be involved in toluene and ethylbenzene adsorption by cuticles wax of plants. Chlorophyll fluorescence analysis or the potential quantum yield of PSII (Fv/Fm) in toluene exposed plants showed no significant differences between the control and the treated plants, whereas plants exposed to ethylbenzene showed significant differences or those parameters, specifically in Dracaena deremensis (Lemon lime), Dracaena sanderiana, Kalanchoe blossfeldiana, and Cordyline fruticosa. The Fv/Fm ratio can give insight into the ability of plants to tolerate (indoor) air pollution by volatile organic chemicals (VOC). This index can be used for identification of suitable plants for treating/sequestering VOCs in contaminated air.

  8. An Improved Design for Air Removal from Aerospace Fluid Loop Coolant Systems

    NASA Technical Reports Server (NTRS)

    Ritchie, Stephen M. C.; Holladay, Jon B.; Holt, J. Mike; Clark, Dallas W.

    2003-01-01

    Aerospace applications with requirements for large capacity heat removal (launch vehicles, platforms, payloads, etc.) typically utilize a liquid coolant fluid as a transport media to increase efficiency and flexibility in the vehicle design. An issue with these systems however, is susceptibility to the presence of noncondensable gas (NCG) or air. The presence of air in a coolant loop can have numerous negative consequences, including loss of centrifugal pump prime, interference with sensor readings, inhibition of heat transfer, and coolant blockage to remote systems. Hardware ground processing to remove this air is also cumbersome and time consuming which continuously drives recurring costs. Current systems for maintaining the system free of air are tailored and have demonstrated only moderate success. An obvious solution to these problems is the development and advancement of a passive gas removal device, or gas trap, that would be installed in the flight cooling system simplifying the initial coolant fill procedure and also maintaining the system during operations. The proposed device would utilize commercially available membranes thus increasing reliability and reducing cost while also addressing both current and anticipated applications. In addition, it maintains current pressure drop, water loss, and size restrictions while increasing tolerance for pressure increases due to gas build-up in the trap.

  9. A novel membrane device for the removal of water vapor and water droplets from air

    NASA Technical Reports Server (NTRS)

    Ray, Rod; Newbold, David D.; Mccray, Scott B.; Friesen, Dwayne T.; Kliss, Mark

    1992-01-01

    One of the key challenges facing NASA engineers is the development of systems for separating liquids and gases in microgravity environments. In this paper, a novel membrane-based phase separator is described. This device, known as a water recovery heat exchanger (WRHEX), overcomes the inherent deficiencies of current phase-separation technology. Specifically, the WRHEX cools and removes water vapor or water droplets from feed-air streams without the use of a vacuum or centrifugal force. As is shown in this paper, only a low-power air blower and a small stream of recirculated cool water is required for WRHEX operation. This paper presents the results of tests using this novel membrane device over a wide range of operating conditions. The data show that the WRHEX produces a dry air stream containing no entrained or liquid water - even when the feed air contains water droplets or mist. An analysis of the operation of the WRHEX is presented.

  10. Statistical estimate of mercury removal efficiencies for air pollution control devices of municipal solid waste incinerators.

    PubMed

    Takahashi, Fumitake; Kida, Akiko; Shimaoka, Takayuki

    2010-10-15

    Although representative removal efficiencies of gaseous mercury for air pollution control devices (APCDs) are important to prepare more reliable atmospheric emission inventories of mercury, they have been still uncertain because they depend sensitively on many factors like the type of APCDs, gas temperature, and mercury speciation. In this study, representative removal efficiencies of gaseous mercury for several types of APCDs of municipal solid waste incineration (MSWI) were offered using a statistical method. 534 data of mercury removal efficiencies for APCDs used in MSWI were collected. APCDs were categorized as fixed-bed absorber (FA), wet scrubber (WS), electrostatic precipitator (ESP), and fabric filter (FF), and their hybrid systems. Data series of all APCD types had Gaussian log-normality. The average removal efficiency with a 95% confidence interval for each APCD was estimated. The FA, WS, and FF with carbon and/or dry sorbent injection systems had 75% to 82% average removal efficiencies. On the other hand, the ESP with/without dry sorbent injection had lower removal efficiencies of up to 22%. The type of dry sorbent injection in the FF system, dry or semi-dry, did not make more than 1% difference to the removal efficiency. The injection of activated carbon and carbon-containing fly ash in the FF system made less than 3% difference. Estimation errors of removal efficiency were especially high for the ESP. The national average of removal efficiency of APCDs in Japanese MSWI plants was estimated on the basis of incineration capacity. Owing to the replacement of old APCDs for dioxin control, the national average removal efficiency increased from 34.5% in 1991 to 92.5% in 2003. This resulted in an additional reduction of about 0.86Mg emission in 2003. Further study using the methodology in this study to other important emission sources like coal-fired power plants will contribute to better emission inventories.

  11. Evaluation of a possible association of urban air toxics and asthma

    SciTech Connect

    Leikauf, G.D.; Kline, S.; Albert, R.E.; Baxter, C.S.

    1995-09-01

    The prevalence of asthma, measured either as the frequency of hospital admission or number of deaths attributed to asthma, has increased over the last 15 to 20 years. Rapid increases in disease prevalence are more likely to be attributable to environmental than genetic factors. inferring from past associations between air pollution and asthma, it is feasible that changes in the ambient environment could contribute to this increase in morbidity and mortality. Scientific evaluation of the links between air pollution and the exacerbation of asthma is incomplete, however. Currently, criteria pollutants [SO{sub x}NO{sub x}, O{sub 3}, CO, Pb, particulate matter (PM{sub 10})] and other risk factors (exposure to environmental tobacco smoke, volatile organic compounds, etc.) are constantly being evaluated as to their possible contributions to this situation. Data from these studies suggest that increases in respiratory disease are associated with exposures to ambient concentrations of particulate and gaseous pollutants. Similarly, exposure to environmental tobacco smoke, also a mixture of particles and gases and that current measurements of air pollution are, in part, indirect in that the concentrations of criteria pollutants are acting as surrogates of our exposure to a complex mixture. Other irritant air pollutants, including certain urban air toxics, are associated with asthma in occupational settings and may interact with criteria pollutants in ambient air to exacerbate asthma. 179 refs., 2 figs., 18 tabs.

  12. Removal of organic contaminant toxicity from sediments - Early work toward development of a toxicity identification evaluation (TIE) method

    USGS Publications Warehouse

    Lebo, J.A.; Huckins, J.N.; Petty, J.D.; Ho, K.T.

    1999-01-01

    Work was performed to determine the feasibility of selectively detoxifying organic contaminants in sediments. The results of this research will be used to aid in the development of a scheme for whole-sediment toxicity identification evaluations (TIEs). The context in which the method will be used inherently restricts the treatments to which the sediments can be subjected: Sediments cannot be significantly altered physically or chemically and the presence and bioavailabilities of other toxicants must not be changed. The methodological problem is daunting because of the requirement that the detoxification method be relatively fast and convenient together with the stipulation that only innocuous and minimally invasive treatments be used. Some of the experiments described here dealt with degrees of decontamination (i.e., detoxification as predicted from instrumental measurements) of spiked sediments rather than with degrees of detoxification as gauged by toxicity tests (e.g., 48-h toxicity tests with amphipods). Although the larger TIE scheme itself is mostly outside the scope of this paper, theoretical aspects of bioavailability and of the desorption of organic contaminants from sediments are discussed.

  13. Low-level NOx removal in ambient air by pulsed corona technology

    NASA Astrophysics Data System (ADS)

    Beckers, F. J. C. M.; Hoeben, W. F. L. M.; Pemen, A. J. M.; van Heesch, E. J. M.

    2013-07-01

    Although removal of NOx by (pulsed) corona discharges has been thoroughly investigated for high concentrations of NOx in flue gas, removal of low levels in ambient air proves to be a difficult task. (Sub) ppm NOx levels exist in traffic tunnels due to accumulation of exhaust gases. The application of pulsed corona technology for purification of traffic tunnel air is studied during a series of lab and field experiments. An industrial pilot scale wire-cylinder type corona reactor has been utilized. Lab tests have been carried out using a diesel generator as NOx source. NOx conversion levels have been determined by applying two Recordum Airpointers (chemiluminescence-based detection). The detector appeared to be cross-sensitive for HNO3 and high levels of O3. NOx removal rates of 60-80% were obtained for inlet levels of 2-10 ppm. The SIE value of 10 ppm NOx removal is 7 J l-1. The corona discharges produce ppm level NOx at high energy densities. This intrinsic NOx production limits removal of inlet levels due to equilibrium between production and oxidation.

  14. Removal of introduced inorganic content from chipped forest residues via air classification

    DOE PAGES

    Lacey, Jeffrey A.; Aston, John E.; Westover, Tyler L.; Cherry, Robert S.; Thompson, David N.

    2015-08-04

    Inorganic content in biomass decreases the efficiency of conversion processes, especially thermochemical conversions. The combined concentrations of specific ash forming elements are the primary attributes that cause pine residues to be considered a degraded energy conversion feedstock, as compared to clean pine. Air classification is a potentially effective and economical tool to isolate high inorganic content biomass fractions away from primary feedstock sources to reduce their ash content. In this work, loblolly pine forest residues were air classified into 10 fractions whose ash content and composition were measured. Ash concentrations were highest in the lightest fractions (5.8–8.5 wt%), and inmore » a heavy fraction of the fines (8.9–15.1 wt%). The removal of fractions with high inorganic content resulted in a substantial reduction in the ash content of the remaining biomass in forest thinnings (1.69–1.07 wt%) and logging residues (1.09–0.68 wt%). These high inorganic content fractions from both forest residue types represented less than 7.0 wt% of the total biomass, yet they contained greater than 40% of the ash content by mass. Elemental analysis of the air classified fractions revealed the lightest fractions were comprised of high concentrations of soil elements (silicon, aluminum, iron, sodium, and titanium). However, the elements of biological origin including calcium, potassium, magnesium, sulfur, manganese, and phosphorous were evenly distributed throughout all air classified fractions, making them more difficult to isolate into fractions with high mineral concentrations. Under the conditions reported in this study, an economic analysis revealed air classification could be used for ash removal for as little as $2.23 per ton of product biomass. As a result, this study suggests air classification is a potentially attractive technology for the removal of introduced soil minerals from pine forest residues.« less

  15. Removal of introduced inorganic content from chipped forest residues via air classification

    SciTech Connect

    Lacey, Jeffrey A.; Aston, John E.; Westover, Tyler L.; Cherry, Robert S.; Thompson, David N.

    2015-08-04

    Inorganic content in biomass decreases the efficiency of conversion processes, especially thermochemical conversions. The combined concentrations of specific ash forming elements are the primary attributes that cause pine residues to be considered a degraded energy conversion feedstock, as compared to clean pine. Air classification is a potentially effective and economical tool to isolate high inorganic content biomass fractions away from primary feedstock sources to reduce their ash content. In this work, loblolly pine forest residues were air classified into 10 fractions whose ash content and composition were measured. Ash concentrations were highest in the lightest fractions (5.8–8.5 wt%), and in a heavy fraction of the fines (8.9–15.1 wt%). The removal of fractions with high inorganic content resulted in a substantial reduction in the ash content of the remaining biomass in forest thinnings (1.69–1.07 wt%) and logging residues (1.09–0.68 wt%). These high inorganic content fractions from both forest residue types represented less than 7.0 wt% of the total biomass, yet they contained greater than 40% of the ash content by mass. Elemental analysis of the air classified fractions revealed the lightest fractions were comprised of high concentrations of soil elements (silicon, aluminum, iron, sodium, and titanium). However, the elements of biological origin including calcium, potassium, magnesium, sulfur, manganese, and phosphorous were evenly distributed throughout all air classified fractions, making them more difficult to isolate into fractions with high mineral concentrations. Under the conditions reported in this study, an economic analysis revealed air classification could be used for ash removal for as little as $2.23 per ton of product biomass. As a result, this study suggests air classification is a potentially attractive technology for the removal of introduced soil minerals from pine forest residues.

  16. National Emission Standard for Hazardous Air Pollutants compliance verification plan for the K-1435 Toxic Substances Control Act Incinerator

    SciTech Connect

    Ambrose, M.L.

    1986-07-28

    This documentation was prepared for submittal to the Environmental Protection Agency (EPA) in order to meet the requirements of the National Emissions Standards for Hazardous Air Pollutants (NESHAP). This document will emphasize the control of radioactive emissions from the K-1435 Toxic Substances Control Act (TSCA) Incinerator. The TSCA Incinerator is a dual purpose solid/liquid incinerator that is under construction at the Oak Ridge Gaseous Diffusion Plant to destroy radioactively contaminated polychlorinated biphenyls (PCBs) and other hazardous organic wastes in compliance with the TSCA and the Resource Conservation and Recovery Act (RCRA). These wastes are generated at the facilities managed by the Department of Energy, Oak Ridge Operations (DOE-ORO). Destruction of the PCBs and the hazardous organic wastes will be accomplished in a rotary kiln incinerator with an afterburner. The incinerator will thermally destroy the organic constituents of the liquids, solids, and sludges to produce an organically inert ash. In addition to the incinerator, an extensive off-gas treatment facility is being constructed to remove particulate and acidic gas air emissions.

  17. Effect of surfactants on the removal and acute toxicity of aqueous nC60 aggregates in water treatment process.

    PubMed

    Ge, Ling; Kirumba, George; Zhang, Bo; Pal, Amrita; He, Yiliang

    2015-07-01

    This work aimed to evaluate the effect of surfactants on the removal of aqueous nC60 aggregates by coagulation-filtration process and assess the acute toxicity of filtrates by Microtox test. Three surfactants including cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS), and Triton X-100 (TX100) were selected representing cationic, anionic, and nonionic types, respectively. Results showed that the change of physicochemical properties of nC60 associating with different types of surfactants determined nC60's removal efficiency and acute toxicity. CTAB increased the number of large particles. It also changed the zeta potential of nC60 from negative to positive, leading to the low removal rates (17.3-50.2%) when CTAB concentration was designed in the range of 0.03-1 g/L, and the filtrates showed acute toxicity to bioluminescent bacteria (inhibition rate > 80%). On the contrary, TX100 obviously increased the proportion of small particles, and it is noteworthy that even less than 1 mg/L of nC60 (20% of the initial concentration) with TX100 remaining in filtrates could evoke phototoxicity due to reactive oxygen species (ROS) generation under UV irradiation. Compared to CTAB and TX100, SDS exerted an effect on the removal process and toxicity of nC60 only when concentration was beyond the critical micelle concentration (CMC; 2.5 g/L). These findings collectively suggest that characteristics of nC60 are flexible and strongly dependent on surfactant modification, as a result of which these particles could potentially find their way through water treatment route and exert a potential toxicity risk.

  18. Membrane air stripping: A process for removal of organics from aqueous solutions

    SciTech Connect

    Mahmud, H.; Kumar, A.; Narbaitz, R.M.; Matsuura, T.

    1998-10-01

    The membrane air-stripping (MAS) process using microporous polypropylene hollow fiber membranes has shown potential for the removal of volatile organics from aqueous streams over conventional treatment processes, particularly in reducing the size of the equipment. This paper reviews the theoretical aspects and experimental investigations on the performance of these membranes in terms of overall mass transfer capabilities in the removal of organics from aqueous solutions. The reported findings of the effect of pH, ozone, chlorine, influence of packing density and possible fouling on the performance of these hollow fibers membranes are presented. The fate of the stripped air is discussed. Other possible applications as well as the future research needs are highlighted, along with critical assessment of the reported work.

  19. Bibliography of work on the photocatalytic removal of hazardous compounds from water and air

    SciTech Connect

    Blake, D.M.

    1994-05-01

    This is a bibliography of information in the open literature on work that has been done to date on the photocatalytic oxidation of compounds, principally organic compounds. The goal of the listing is removing hazardous oompounds from water or air. It contains lists of substances and literature citations. The bibliography includes information obtained through the middle of 1993 and some selected references for the balance of that year.

  20. Decontamination of aquatic vegetable leaves by removing trace toxic metals during pickling process with acetic acid solution.

    PubMed

    Wu, Wenbiao; Yang, Yixing

    2011-01-01

    The heavy-metal content of aquatic plants is mainly dependent upon their ecological system. This study indicated that although the toxic heavy-metal contents could be above the recommended maximum levels depending upon their concentrations in growing water, they can be decontaminated by pickling with 5% acetic acid solution. Almost all Cd, Hg, Ba, or Sb and 99.5% Pb, 96.7% Ag, or 97.1% Al were removed from Water Spinach leaves by soaking in acetic acid solution. For Water-Shield leaves, almost all Cd, Hg, Pb, Ba, or Sb and 95.0% Ag or 96.1% Al were removed. For Watercress leaves, almost all Cd, Hg, Ba, or Sb and 99.0% Pb or 99.7% Ag were removed. For Water Hyacinth leaves, almost all Cd, Ba, or Sb and 99.0% Hg, 98.5% Pb, 95.0% Ag, or 98.7% Al were removed.

  1. Decontamination of aquatic vegetable leaves by removing trace toxic metals during pickling process with acetic acid solution.

    PubMed

    Wu, Wenbiao; Yang, Yixing

    2011-01-01

    The heavy-metal content of aquatic plants is mainly dependent upon their ecological system. This study indicated that although the toxic heavy-metal contents could be above the recommended maximum levels depending upon their concentrations in growing water, they can be decontaminated by pickling with 5% acetic acid solution. Almost all Cd, Hg, Ba, or Sb and 99.5% Pb, 96.7% Ag, or 97.1% Al were removed from Water Spinach leaves by soaking in acetic acid solution. For Water-Shield leaves, almost all Cd, Hg, Pb, Ba, or Sb and 95.0% Ag or 96.1% Al were removed. For Watercress leaves, almost all Cd, Hg, Ba, or Sb and 99.0% Pb or 99.7% Ag were removed. For Water Hyacinth leaves, almost all Cd, Ba, or Sb and 99.0% Hg, 98.5% Pb, 95.0% Ag, or 98.7% Al were removed. PMID:21888602

  2. Evaluation of mercury speciation and removal through air pollution control devices of a 190 MW boiler.

    PubMed

    Wu, Chengli; Cao, Yan; Dong, Zhongbing; Cheng, Chinmin; Li, Hanxu; Pan, Weiping

    2010-01-01

    Air pollution control devices (APCDs) are installed at coal-fired power plants for air pollutant regulation. Selective catalytic reduction (SCR) and wet flue gas desulfurization (FGD) systems have the co-benefits of air pollutant and mercury removal. Configuration and operational conditions of APCDs and mercury speciation affect mercury removal efficiently at coal-fired utilities. The Ontario Hydro Method (OHM) recommended by the U.S. Environmental Protection Agency (EPA) was used to determine mercury speciation simultaneously at five sampling locations through SCR-ESP-FGD at a 190 MW unit. Chlorine in coal had been suggested as a factor affecting the mercury speciation in flue gas; and low-chlorine coal was purported to produce less oxidized mercury (Hg2+) and more elemental mercury (Hg0) at the SCR inlet compared to higher chlorine coal. SCR could oxidize elemental mercury into oxidized mercury when SCR was in service, and oxidation efficiency reached 71.0%. Therefore, oxidized mercury removal efficiency was enhanced through a wet FGD system. In the non-ozone season, about 89.5%-96.8% of oxidized mercury was controlled, but only 54.9%-68.8% of the total mercury was captured through wet FGD. Oxidized mercury removal efficiency was 95.9%-98.0%, and there was a big difference in the total mercury removal efficiencies from 78.0% to 90.2% in the ozone season. Mercury mass balance was evaluated to validate reliability of OHM testing data, and the ratio of mercury input in the coal to mercury output at the stack was from 0.84 to 1.08.

  3. Evaluation of mercury speciation and removal through air pollution control devices of a 190 MW boiler.

    PubMed

    Wu, Chengli; Cao, Yan; Dong, Zhongbing; Cheng, Chinmin; Li, Hanxu; Pan, Weiping

    2010-01-01

    Air pollution control devices (APCDs) are installed at coal-fired power plants for air pollutant regulation. Selective catalytic reduction (SCR) and wet flue gas desulfurization (FGD) systems have the co-benefits of air pollutant and mercury removal. Configuration and operational conditions of APCDs and mercury speciation affect mercury removal efficiently at coal-fired utilities. The Ontario Hydro Method (OHM) recommended by the U.S. Environmental Protection Agency (EPA) was used to determine mercury speciation simultaneously at five sampling locations through SCR-ESP-FGD at a 190 MW unit. Chlorine in coal had been suggested as a factor affecting the mercury speciation in flue gas; and low-chlorine coal was purported to produce less oxidized mercury (Hg2+) and more elemental mercury (Hg0) at the SCR inlet compared to higher chlorine coal. SCR could oxidize elemental mercury into oxidized mercury when SCR was in service, and oxidation efficiency reached 71.0%. Therefore, oxidized mercury removal efficiency was enhanced through a wet FGD system. In the non-ozone season, about 89.5%-96.8% of oxidized mercury was controlled, but only 54.9%-68.8% of the total mercury was captured through wet FGD. Oxidized mercury removal efficiency was 95.9%-98.0%, and there was a big difference in the total mercury removal efficiencies from 78.0% to 90.2% in the ozone season. Mercury mass balance was evaluated to validate reliability of OHM testing data, and the ratio of mercury input in the coal to mercury output at the stack was from 0.84 to 1.08. PMID:20397418

  4. Portable air pollution control equipment for the control of toxic particulate emissions

    SciTech Connect

    Chaurushia, A.; Odabashian, S.; Busch, E.

    1997-12-31

    Chromium VI (Cr VI) has been identified by the environmental regulatory agencies as a potent carcinogen among eleven heavy metals. A threshold level of 0.0001 lb/year for Cr VI emissions has been established by the California Air Resources Board for reporting under Assembly Bill 2588. A need for an innovative control technology to reduce fugitive emissions of Cr VI was identified during the Air Toxic Emissions Reduction Program at Northrop Grumman Military Aircraft Systems Division (NGMASD). NGMASD operates an aircraft assembly facility in El Segundo, CA. Nearly all of the aircraft components are coated with a protective coating (primer) prior to assembly. The primer has Cr VI as a component for its excellent corrosion resistance property. The complex assembly process requires fasteners which also need primer coating. Therefore, NGMASD utilizes High Volume Low Pressure (HVLP) guns for the touch-up spray coating operations. During the touch-up spray coating operations, Cr VI particles are atomized and transferred to the aircraft surface. The South Coast Air Quality Management District (SCAQMD) has determined that the HVLP gun transfers 65% of the paint particles onto the substrate and the remaining 35% are emitted as an overspray if air pollution controls are not applied. NGMASD has developed the Portable Air Pollution Control Equipment (PAPCE) to capture and control the overspray in order to reduce fugitive Cr VI emissions from the touch-up spray coating operations. A source test was performed per SCAQMD guidelines and the final report has been approved by the SCAQMD.

  5. Hydrocarbon removal from bilgewater by a combination of air-stripping and photocatalysis.

    PubMed

    Cazoir, D; Fine, L; Ferronato, C; Chovelon, J-M

    2012-10-15

    In order to prevent hydrocarbon discharge at sea from the bilge of ships, the International Maritime Organization (IMO) enacted the MARPOL 73/78 convention in which effluents are now limited to those with maximum oil content of 15 ppmv. Thus, photocatalysis and air-stripping were combined for the hydrocarbon removal from a real oily bilgewater sample and an original monitoring of both aqueous and gaseous phases was performed by GC/MS to better understand the process. Our results show that the hydrocarbon oil index [HC] can be reduced to its maximum permissible value of 15 ppmv (MARPOL) in only 8.5h when photocatalysis and air-stripping are used together in a synergistic way, as against 17 h when photocatalysis is used alone. However, this air-assisted photocatalytic process emits a large quantity of volatile organic compounds (VOC) and, within the first four hours, ca. 10% of the hydrocarbon removal in the aqueous phase is actually just transferred into the gaseous one. Finally, we highlight that the n-alkanes with a number of carbon atoms higher than 15 (N(C)>15) are those which most decrease the rate of [HC] removal.

  6. Mobile Laboratory Measurements of On-Road Vehicle Air Toxics Emissions in Mexico City

    NASA Astrophysics Data System (ADS)

    Kolb, C. E.; Herndon, S. C.; Zavala, M.; Knighton, B.; Marr, L. C.; Zahniser, M. S.; Jayne, J. T.; Shorter, J. H.; Onasch, T. B.; Canagaratna, M. R.; Worsnop, D. R.; Molina, L. T.; Molina, M. J.

    2004-12-01

    The direct emission of toxic organic pollutants from mobile sources is an issue of growing concern. The U.S. Environmental Protection Agency (EPA) and the Federal Highway Administration (FHWA) have identified formaldehyde, acetaldehyde, benzene, acrolein, 1.3 butadiene, and diesel particulate matter (PM), including associated organic compounds, as mobile emissions of priority concern. Real-time trace gas and fine PM sensors deployed on the Aerodyne Research Mobile Laboratory have been used to characterize both fleet average and individual vehicle class on-road emissions of formaldehyde, acetaldehyde, benzene, and diesel particulate matter (PM), including associated organic compounds in the Mexico City Metropolitan Area (MCMA). Data for these air toxics emissions will be reviewed and compared to similar data taken in Boston and New York City, where available. The prospects for future on-road real-time monitoring of acroleinand1.3 butadiene will be discussed.

  7. Stability of air toxic gases listed in Title III Clean Air Act Amendments

    SciTech Connect

    Jayanty, R.K.M.; Jaffe, L.B.; Albritton, J.R.; Jackson, M.D.; Midgett, M.R.

    1992-01-01

    A repository of 59 organic compounds has been established by the U.S. Environmental Protection Agency (EPA) for use as gas standards in performance audits during field validation of emission concentrations from stationary sources. These compounds are listed in Title III of the 1990 Clean Air Act Amendment. The compounds are prepared in compressed gas cylinders and recyclable aluminum containers. Three concentration ranges were selected: low (20 to 200 ppb), mid-level (0.5 to 5 ppm), and high (5 to 50 ppm). The recyclable aluminum containers were only prepared in the low range, and pressures were generally below 400 psig. The compressed gas cylinders contained pressures up to 2000 psig. In this program to ensure that the concentration of each gas standard had not changed, each standard was analyzed periodically for stability. The gas mixtures were analyzed by the manufacturer before shipment. They were then analyzed upon receipt, and reanalyzed periodically to determine any change in concentration. The stability data obtained to date indicates that many compounds are stable in the compressed gas cylinders; however, some of the compounds in the recyclable containers are not stable.

  8. Removal of toxic zinc from water/wastewater using eucalyptus seeds activated carbon: non-linear regression analysis.

    PubMed

    Senthil Kumar, Ponnusamy; Saravanan, Anbalagan; Anish Kumar, Kodyingil; Yashwanth, Ramesh; Visvesh, Sridharan

    2016-08-01

    In the present study, a novel activated carbon was prepared from low-cost eucalyptus seeds, which was utilised for the effectively removal of toxic zinc from the water/wastewater. The prepared adsorbent was studied by Fourier transform infrared spectroscopy and scanning electron microscopic characterisation studies. Adsorption process was experimentally performed for optimising the influencing factors such as adsorbent dosage, solution pH, contact time, initial zinc concentration, and temperature for the maximum removal of zinc from aqueous solution. Adsorption isotherm of zinc removal was ensued Freundlich model, and the kinetic model ensued pseudo-second order model. Langmuir monolayer adsorption capacity of the adsorbent for zinc removal was evaluated as 80.37 mg/g. The results of the thermodynamic studies suggested that the adsorption process was exothermic, thermodynamically feasible and impulsive process. Finally, a batch adsorber was planned to remove zinc from known volume and known concentration of wastewater using best obeyed model such as Freundlich. The experimental details showed the newly prepared material can be effectively utilised as a cheap material for the adsorption of toxic metal ions from the contaminated water. PMID:27463796

  9. Removing volatile contaminants from the unsaturated zone by inducing advective air-phase transport

    USGS Publications Warehouse

    Baehr, A.L.; Hoag, G.E.; Marley, M.C.

    1989-01-01

    Organic liquids inadvertently spilled and then distributed in the unsaturated zone can pose a long-term threat to ground water. Many of these substances have significant volatility, and thereby establish a premise for contaminant removal from the unsaturated zone by inducing advective air-phase transport with wells screened in the unsaturated zone. In order to focus attention on the rates of mass transfer from liquid to vapour phases, sand columns were partially saturated with gasoline and vented under steady air-flow conditions. The ability of an equilibrium-based transport model to predict the hydrocarbon vapor flux from the columns implies an efficient rate of local phase transfer for reasonably high air-phase velocities. Thus the success of venting remediations will depend primarily on the ability to induce an air-flow field in a heterogeneous unsaturated zone that will intersect the distributed contaminant. To analyze this aspect of the technique, a mathematical model was developed to predict radially symmetric air flow induced by venting from a single well. This model allows for in-situ determinations of air-phase permeability, which is the fundamental design parameter, and for the analysis of the limitations of a single well design. A successful application of the technique at a site once contaminated by gasoline supports the optimism derived from the experimental and modeliing phases of this study, and illustrates the well construction and field methods used to document the volatile contaminant recovery. ?? 1989.

  10. Effect of Air-Polishing on Titanium Surfaces, Biofilm Removal, and Biocompatibility: A Pilot Study

    PubMed Central

    Bennani, Vincent; Hwang, Linda; Tawse-Smith, Andrew; Dias, George J.; Cannon, Richard D.

    2015-01-01

    Purpose. The aims of this in vitro study were to evaluate morphological changes induced by glycine powder air-polishing on titanium surfaces, biofilm removal, and biocompatibility. Material and Methods. Titanium grade IV discs were allocated into two groups: (1) discs without biofilm and (2) discs for Streptococcus mutans biofilm formation. Discs in each group were further subdivided into (a) no treatment and (b) air-polishing treatment with glycine powder. Discs were characterized by scanning electron microscopy (SEM), electron-dispersive spectroscopy (EDS), and confocal microscopy. Bacterial biofilms were quantified using a crystal violet dye-binding assay. Biocompatibility was evaluated by measuring the coverage and viability of L929 fibroblast cells cultured on the discs. Results. Air-polishing increased the roughness of treated discs (P < 0.05). EDS analysis did not show significant differences in the chemical composition of treated and nontreated discs. The amount of residual biofilm on treated discs was 8.6-fold lower than untreated controls (P < 0.05). Coverage of treated discs by fibroblasts was half that of untreated discs (P < 0.05) although both groups had the same cell viability. Conclusions. Air-polishing removed a significant amount of biofilm from titanium surfaces. The “polishing” was accompanied by increased surface roughness, but there were no changes in chemical and elemental compositions, nor the biocompatibility. PMID:26881198

  11. Removal and fate of Cryptosporidium in dissolved air drinking water treatment plants.

    PubMed

    Edzwald, J K; Tobiason, J E; Dunn, H; Kaminski, G; Galant, P

    2001-01-01

    In the first part of the paper, data from pilot plant studies are used to evaluate Cryptosporidium removal by dissolved air flotation (DAF) clarification and dual media filters under challenge conditions. Oocyst removals were investigated for design detention times and hydraulic loadings for winter and spring seasons. Coagulation was optimized for turbidity and removal of natural organic matter. DAF performance was better for spring water temperatures achieving 2.5 +/- 0.3 log removal of oocysts compared to 1.7 +/- 0.3 log removal in the winter. Cumulative log removal across DAF and filtration exceeded 5.4, and was not affected by water temperature. Low turbidities and particle counts are indicators of good treatment and good removals of Cryptosporidium. The second part of the paper uses a mathematical model to predict the fate of Cryptosporidium through a DAF plant and the impact of filter backwash recycle on oocyst build-up in the plant influent. Model predictions show that the fate of Cryptosporidium and the build-up of oocysts in the plant influent depend on: DAF performance, the percent of filtered water production used for backwashing, and the percent of filter backwash recycle flow. A DAF plant with 2.5% filtered water production for backwashing and that achieves 1.6 log removal or greater of oocysts by DAF clarification will not have a build-up of oocysts in the plant influent regardless of the recycle rate. This is because the oocysts are concentrated in the DAF floated sludge and not within granular filters.

  12. Toxic gas removal--metal-organic frameworks for the capture and degradation of toxic gases and vapours.

    PubMed

    Barea, Elisa; Montoro, Carmen; Navarro, Jorge A R

    2014-08-21

    The release of anthropogenic toxic pollutants into the atmosphere is a worldwide threat of growing concern. In this regard, it is possible to take advantage of the high versatility of MOFs materials in order to develop new technologies for environmental remediation purposes. Consequently, one of the main scientific challenges to be achieved in the field of MOF research should be to maximize the performance of these solids towards the sensing, capture and catalytic degradation of harmful gases and vapors by means of a rational control of size and reactivity of the pore walls that are directly accessible to guest molecules.

  13. LINKING AIR TOXIC CONCENTRATIONS FROM CMAQ TO THE HAPEM5 EXPOSURE MODEL AT NEIGHORHOOD SCALES FOR THE PHILADELPHIA AREA

    EPA Science Inventory

    This paper provides a preliminary demonstration of the EPA neighborhood scale modeling paradigm for air toxics by linking concentration from the Community Multi-scale Air Quality (CMAQ) modeling system to the fifth version of the Hazardous Pollutant Exposure Model (HAPEM5). For ...

  14. An Evaluation of EPA's National-Scale Air Toxics Assessment (NATA): Comparison with Benzene Measurements in Detroit, Michigan

    EPA Science Inventory

    The U.S. EPA periodically evaluates ambient concentrations, human exposures, and health risks for 180 hazardous air pollutants plus diesel particulate matter using modeled estimates from the National-Scale Air Toxics Assessment (NATA). NATA publishes estimates at the spatial reso...

  15. FURTHER REFINEMENTS AND TESTING OF APEX3.0: EPA'S POPULATION EXPOSURE MODEL FOR CRITERIA AND AIR TOXIC INHALATION

    EPA Science Inventory

    The Air Pollutants Exposure Model (APEX(3.0)) is a PC-based model that was derived from the probabilistic NAAQS Exposure Model for carbon monoxide (pNEM/CO). APEX will be one of the tools used to estimate human population exposure for criteria and air toxic pollutants as part ...

  16. Polychlorinated naphthalenes in the air over the equatorial Indian Ocean: Occurrence, potential sources, and toxicity.

    PubMed

    Huang, Yumei; Li, Jun; Xu, Yue; Xu, Weihai; Zhong, Guangcai; Liu, Xiang; Zhang, Gan

    2016-06-15

    Monitoring of marine polychlorinated naphthalenes (PCNs) is crucial, as they are considered persistent organic pollutants (POPs) by the Stockholm Convention. Data on PCNs in marine environment are scarce. In this study, 19 air samples were collected during a cruise in the equatorial Indian Ocean on board the Chinese research vessel Shiyan I from 4/2011 to 5/2011. PCN concentration of these air samples ranged from 0.033 to 2.56pgm(-3), with an average of 0.518pgm(-3), equal to or lower than the values reported for other oceans, seas, and lakes worldwide. Tri- and tetra-CNs were the main homologues in most samples. Reemission of Halowax mixtures and incineration processes were the major sources of atmospheric PCNs in the study area. The PCN-corresponding toxic equivalency values ranged from 0 to 0.190fgm(-3) (average: 0.038fgm(-3)), falling in the low end of global range.

  17. A Broad Spectrum Catalytic System for Removal of Toxic Organics from Water by Deep Oxidation - Final Report

    SciTech Connect

    Sen, Ayusman

    2000-12-01

    A most pressing need for the DOE environmental management program is the removal of toxic organic compounds present in groundwater and soil at specific DOE sites. While several remediation procedures have been proposed, they suffer from one or more drawbacks. The objective of the present research was to develop new catalytic procedures for the removal of toxic organic compounds from the environment through their deep oxidation to harmless products. In water, metallic palladium was found to catalyze the deep oxidation of a wide variety of toxic organic compounds by dioxygen at 80-90 C in the presence of carbon monoxide or dihydrogen. Several classes of organic compounds were examined: benzene, phenol and substituted phenols, nitro and halo organics, organophosphorus, and organosulfur compounds. In every case, deep oxidation to carbon monoxide, carbon dioxide, and water occurred in high yields, resulting in up to several hundred turnovers over a 24 hour period. For substrates susceptible to hydrogenation, the conversions were generally high with dihydrogen than with carbon monoxide. It is clear from the results obtained that we have discovered an exceptionally versatile catalytic system for the deep oxidation of toxic organic compounds in water. This system possesses several attractive features not found simultaneously in other reported systems. These are (a) the ability to directly utilize dioxygen as the oxidant, (b) the ability to carry out the deep oxidation of a particularly wide range of functional organics, and (c) the ease of recovery of the catalyst by simple filtration.

  18. Projections of air toxic emissions from coal-fired utility combustion: Input for hazardous air pollutant regulators

    SciTech Connect

    Szpunar, C.B.

    1993-08-01

    The US Environmental Protection Agency (EPA) is required by the 1990 CAAA to promulgate rules for all ``major`` sources of any of these HAPs. According to the HAPs section of the new Title III, any stationary source emitting 10 tons per year (TPY) of one HAP or 25 TPY of a combination of HAPs will be considered and designated a major source. In contrast to the original National Emission Standards for Hazardous Air Pollutants (NESHAP), which were designed to protect public health to ``an ample margin of safety,`` the new Title III, in its first phase, will regulate by industrial category those sources emitting HAPs in excess of the 10/25-TPY threshold levels, regardless of health risks. The trace elements normally associated with coal mineral matter and the various compounds formed during coal combustion have the potential to produce hazardous air toxic emissions from coal-fired electric utilities. Under Title III, the EPA is required to perform certain studies, prior to any regulation of electric utilities; these studies are currently underway. Also, the US Department of Energy (DOE) maintains a vested interest in addressing those energy policy questions affecting electric utility generation, coal mining, and steel producing critical to this country`s economic well-being, where balancing the costs to the producers and users of energy with the benefits of environmental protection to the workers and the general populace remains of significant concern.

  19. Evaluation of ozone generation and indoor organic compounds removal by air cleaners based on chamber tests

    NASA Astrophysics Data System (ADS)

    Yu, Kuo-Pin; Lee, Grace Whei-May; Hsieh, Ching-Pei; Lin, Chi-Chi

    2011-01-01

    Ozone can cause many health problems, including exacerbation of asthma, throat irritation, cough, chest ache, shortness of breath, and respiratory infections. Air cleaners are one of the sources of indoor ozone, and thus the evaluation of ozone generated by air cleaners is desired significant issue. Most evaluation methods proposed are based on chamber tests. However, the adsorption and desorption of ozone on the wall of test chamber and the deposition of ozone resulted from the surface reaction can influence the evaluation results. In this study, we developed a mass balance model that took the adsorption, desorption and deposition of ozone into consideration to evaluate the effective ozone emission rates of six selected air cleaners. The experiments were conducted in a stainless steel chamber with a volume of 11.3 m 3 at 25 °C and 60% relative humidity. The adsorption, desorption and deposition rate constants of ozone obtained by fitting the model to the experimental data were k a = 0.149 ± 0.052 m h -1, k d = 0.013 ± 0.007 h -1, and k r = 0.050 ± 0.020 h -1, respectively. The effective ozone emission rates of Air Cleaners No. 1, 2, and 3 ranged between 13,400-24,500 μg h -1, 7190-10,400 μg h -1, and 4880-6560 μg h -1, respectively, which were more stable than those of No.4, 5, and 6. The effective ozone emission rates of Air Cleaners No. 4, 5, and 6 increased with the time of operation which might be relevant to the decrease of ozone removal by the "aging" filter installed in these cleaners. The removal of toluene and formaldehyde by these six air cleaners were also evaluated and the clean air delivery rates (CADRs) of these two pollutants ranged from non-detectable to 0.42 ± 0.08 m 3 h -1, and from non-detectable to 0.75 ± 0.07 m 3 h -1, respectively. The CADRs showed an insignificant relationship with the effective ozone emission rates. Thus, the removal of toluene and formaldehyde might be resulted from the adsorption on the filters and the

  20. Biomarkers for assessing body burden from exposure to toxic air pollutants

    SciTech Connect

    Gordon, S.M.; O'Neill, H.J.; Moschandreas, D.J. ); Lewis, R.G.; Wilson, N.K. )

    1988-09-01

    The body burden of airborne toxic chemicals resulting from all routes of human exposure cannot be determined by traditional techniques, which only measure the concentrations of these chemicals in air. Human exposure has been related to biological endpoints in several studies using biochemical markers. It may be possible to relate human exposure to breath concentrations, biological endpoints, and ultimately body burden, using noninvasive techniques (breath and urine analysis). Preliminary chamber studies in their laboratory have shown that subjects exposed to selected air pollutants at near-normal ambient levels eliminate them in breath at measurable decay rates. This study seeks to determine expired-air decay rates for selected air pollutants and their blood/breath partition coefficients. Such data could lead to correlations with the primary biomarkers directly related to biological endpoints (e.g., DNA or protein adducts, glutathione conjugates, chromosomal damage, immune function impairment). If an association can be established between noninvasive data and primary biomarkers, then an integrated approach should be possible for measuring biological endpoints noninvasively by monitoring human expired breath or urine.

  1. A model of particle removal in a dissolved air flotation tank: importance of stratified flow and bubble size.

    PubMed

    Lakghomi, B; Lawryshyn, Y; Hofmann, R

    2015-01-01

    An analytical model and a computational fluid dynamic model of particle removal in dissolved air flotation were developed that included the effects of stratified flow and bubble-particle clustering. The models were applied to study the effect of operating conditions and formation of stratified flow on particle removal. Both modeling approaches demonstrated that the presence of stratified flow enhanced particle removal in the tank. A higher air fraction was shown to be needed at higher loading rates to achieve the same removal efficiency. The model predictions showed that an optimum bubble size was present that increased with an increase in particle size.

  2. Long-term performance of passive materials for removal of ozone from indoor air.

    PubMed

    Cros, C J; Morrison, G C; Siegel, J A; Corsi, R L

    2012-02-01

    The health effects associated with exposure to ozone range from respiratory irritation to increased mortality. In this paper, we explore the use of three green building materials and an activated carbon (AC) mat that remove ozone from indoor air. We studied the effects of long-term exposure of these materials to real environments on ozone removal capability and pre- and post-ozonation emissions. A field study was completed over a 6-month period, and laboratory testing was intermittently conducted on material samples retrieved from the field. The results show sustained ozone removal for all materials except recycled carpet, with greatest ozone deposition velocity for AC mat (2.5-3.8 m/h) and perlite-based ceiling tile (2.2-3.2 m/h). Carbonyl emission rates were low for AC across all field sites. Painted gypsum wallboard and perlite-based ceiling tile had similar overall emission rates over the 6-month period, while carpet had large initial emission rates of undesirable by-products that decayed rapidly but remained high compared with other materials. This study confirms that AC mats and perlite-based ceiling tile are viable surfaces for inclusion in buildings to remove ozone without generating undesirable by-products. PRACTICAL IMPLICATIONS The use of passive removal materials for ozone control could decrease the need for, or even render unnecessary, active but energy consuming control solutions. In buildings where ozone should be controlled (high outdoor ozone concentrations, sensitive populations), materials specifically designed or selected for removing ozone could be implemented, as long as ozone removal is not associated with large emissions of harmful by-products. We find that activated carbon mats and perlite-based ceiling tiles can provide substantial, long-lasting, ozone control.

  3. Sampling of air streams and incorporation of samples in the Microtox{trademark} toxicity testing system

    SciTech Connect

    Kleinheinz, G.T.; St. John, W.P.

    1997-10-01

    A study was conducted to develop a rapid and reliable method for the collection and incorporation of biofiltration air samples containing volatile organic compounds (VOCs) into the Microtox toxicity testing system. To date, no method exists for this type of assay. A constant stream of VOCs was generated by air stripping compounds from a complex mixture of petroleum hydrocarbons (PHCs). Samples were collected on coconut charcoal ORBO tubes and the VOCs extracted with methylene chloride. The compounds extracted were then solvent exchanged into dimethyl sulfoxide (DMSO) under gaseous nitrogen. The resulting DMSO extract was directly incorporated into the Microtox toxicity testing system. In order to determine the efficiency of the solvent exchange, the VOCs in the DMSO extract were then extracted into hexane and subsequently analyzed using gas chromatography (GC) with a flame ionization detector (FID). It was determined that all but the most volatile VOCs could be effectively transferred from the ORBO tubes to DMSO for Microtox testing. Potential trace amounts of residual methylene chloride in the DMSO extracts showed no adverse effects in the Microtox system when compared to control samples.

  4. Toxicity Assessment of Air-delivered Particle-bound Polybrominated Diphenyl Ethers

    PubMed Central

    Kim, Jong Sung; Klösener, Johannes; Flor, Susanne; Peters, Thomas M.; Ludewig, Gabriele; Thorne, Peter S.; Robertson, Larry W.; Luthe, Gregor

    2014-01-01

    Human exposure to polybrominated diphenyl ether (PBDE) can occur via ingestion of indoor dust, inhalation of PBDE-contaminated air and dust-bound PBDEs. However, few studies have examined the pulmonary toxicity of particle-bound PBDEs, mainly due to the lack of an appropriate particle-cell exposure system. In this study we developed an in vitro exposure system capable of generating particle-bound PBDEs mimicking dusts containing PBDE congeners (BDEs 35, 47, 99) and delivering them directly onto lung cells grown at an air-liquid interface (ALI). The silica particles and particle-coated with PBDEs ranged in diameter from 4.3 to 4.5 μm and were delivered to cells with no apparent aggregation. This experimental set up demonstrated high reproducibility and sensitivity for dosing control and distribution of particles. ALI exposure of cells to PBDE-bound particles significantly decreased cell viability and induced reactive oxygen species generation in A549 and NCI-H358 cells. In male Sprague-Dawley rats exposed via intratracheal insufflation (0.6 mg/rat), particle-bound PBDE exposures induced inflammatory responses with increased recruitment of neutrophils to the lungs compared to sham-exposed rats. The present study clearly indicates the potential of our exposure system for studying the toxicity of particle-bound compounds. PMID:24451063

  5. Biofiltration of wastewater treatment plant effluent: effective removal of pharmaceuticals and personal care products and reduction of toxicity.

    PubMed

    Reungoat, J; Escher, B I; Macova, M; Keller, J

    2011-04-01

    This study investigates biofiltration for the removal of dissolved organic carbon (DOC), pharmaceuticals and personal care products (PPCPs), and for the reduction of non-specific toxicity expressed as baseline toxicity equivalent concentration (baseline-TEQ). Two filtering media, sand and granular activated carbon, were tested. The influence of pre-ozonation and empty-bed contact time (EBCT, from 30 to 120 min) was determined. The experiments were performed at a pilot-scale with real WWTP effluent. A previous study showed that biological activity had developed on the filtering media and dissolved organic removal had reached a steady state before sampling commenced. The results show that biological activated carbon (BAC) has a good potential for the removal of DOC (35-60%), PPCPs (>90%) and baseline-TEQ (28-68%) even without pre-ozonation. On the contrary, the sand shows limited improvement of effluent quality. Varying the EBCT does not influence the performance of the BAC filters; however, dissolved oxygen concentration could be a limiting factor. The performances of the BAC filters were stable for over two years suggesting that the main mechanism of organic matter and PPCPs removal is biodegradation. It is concluded that BAC filtration without pre-ozonation could be implemented as a low cost advanced treatment option to improve WWTP effluent chemical quality. PMID:21450327

  6. Influence of initial pesticide concentrations and plant population density on dimethomorph toxicity and removal by two duckweed species.

    PubMed

    Dosnon-Olette, Rachel; Couderchet, Michel; El Arfaoui, Achouak; Sayen, Stéphanie; Eullaffroy, Philippe

    2010-04-15

    Aquatic plants take up, transform and sequester organic contaminants and may therefore be used in phytoremediation for the removal of pollutants from wastewaters. A better understanding of factors affecting the rate of contaminant uptake by aquatic plants is needed to improve engineered systems for removal of pollutants from wastewaters. This work focused on the influence of initial concentrations of pesticide and population density of plants on toxicity and uptake of the fungicide dimethomorph by two duckweed species. An increased sensitivity to dimethomorph was observed with increasing duckweed population density. Less light, due to crowding, may explain this higher sensitivity and reduced removal rate. A positive relationship was also found between toxicity or contaminant uptake and initial pesticide concentration with a maximal removal of 41 and 26 microg g(-1) fresh weight of dimethomorph (at 600 microg L(-1) of dimethomorph and an initial density of 0.10g E-flask(-1)) by Lemna minor and Spirodela polyrhiza, respectively. This research also indicated that these aquatic plants can efficiently eliminate organic contaminants and may ultimately serve as phytoremediation agents in the natural environment.

  7. Removal of dissolved VOCs from water with an air stripper/membrane vapor separation system

    SciTech Connect

    Wijmans, J.G.; Kamaruddin, H.D.; Segelke, S.V.; Wessling, M.; Baker, R.W.

    1997-09-01

    Treatment of water contaminated with volatile organic compounds (VOCs) is a major problem for the United States chemical industry. Currently, VOCs are removed from moderately contaminated wastewater streams by processes such as steam stripping and from dilute wastewaters by air stripping combined with a carbon adsorption off-gas treatment system. This paper describes the development and performance of a hybrid process that combines air stripping with membrane organic-vapor separation to recover VOCs from the stripper off-gas. A number of prototype systems have been constructed and evaluated. The optimum system appears to be a tray stripper fitted with a high-pressure compression-condensation membrane separation unit. Such a system can remove 95 to 99% of the VOCs present in contaminated water; the removed VOCs are recovered as a liquid condensate. The economics of the technology are competitive with alternative processes, particularly for streams containing more than 500 ppm VOC and having flow rates less than 10 to 30 gal/min.

  8. Removal of polycyclic aromatic hydrocarbons (PAHs) from industrial sludges in the ambient air conditions: automotive industry.

    PubMed

    Karaca, Gizem; Tasdemir, Yucel

    2013-01-01

    Removal of polycyclic aromatic hydrocarbons (PAHs) existed in automotive industry treatment sludge was examined by considering the effects of temperature, UV, titanium dioxide (TiO2) and diethyl amine (DEA) in different dosages (i.e., 5% and 20%) in this study. Application of TiO2 and DEA to the sludge samples in ambient environment was studied. Ten PAH (Σ10 PAH) compounds were targeted and their average value in the sludge was found to be 4480 ± 1450 ng/g dry matter (DM). Total PAH content of the sludge was reduced by 25% in the ambient air environment. Meteorological conditions, atmospheric deposition, evaporation and sunlight irradiation played an effective role in the variations in PAH levels during the tests carried out in ambient air environment. Moreover, it was observed that when the ring numbers of PAHs increased, their removal rates also increased. Total PAH level did not change with the addition of 5% DEA and only 10% decreased with 5% TiO2 addition. PAH removal ratios were 8% and 32% when DEA (20%) and TiO2 (20%) were added, respectively. It was concluded that DEA was a weak photo-sensitizer yet TiO2 was effective only at 20% dosage.

  9. A hybrid biological process of indoor air treatment for toluene removal.

    PubMed

    Hort, C; Platel, V; Sochard, S; Munoz, Luengas A T; Ondarts, M; Reguer, A; Barona, A; Elias, A

    2014-12-01

    Bioprocesses, such as biofiltration, are commonly used to treat industrial effluents containing volatile organic compounds (VOCs) at low concentrations. Nevertheless, the use of biofiltration for indoor air pollution (IAP) treatment requires adjustments depending on specific indoor environments. Therefore, this study focuses on the convenience of a hybrid biological process for IAP treatment. A biofiltration reactor using a green waste compost was combined with an adsorption column filled with activated carbon (AC). This system treated a toluene-micropolluted effluent (concentration between 17 and 52 μg/m3), exhibiting concentration peaks close to 733 μg/m3 for a few hours per day. High removal efficiency was obtained despite changes in toluene inlet load (from 4.2 x 10(-3) to 0.20 g/m3/hr), which proves the hybrid system's effectiveness. In fact, during unexpected concentration changes, the efficiency of the biofilter is greatly decreased, but the adsorption column maintains the high efficiency of the entire process (removal efficiency [RE] close to 100%). Moreover, the adsorption column after biofiltration is able to deal with the problem of the emission of particles and/or microorganisms from the biofilter. Implications: Indoor air pollution is nowadays recognized as major environmental and health issue. This original study investigates the performance of a hybrid biological process combining a biofilter and an adsorption column for removal of indoor VOCs, specifically toluene.

  10. Industrial CO2 Removal: CO2 Capture from Ambient Air and Geological Sequestration

    SciTech Connect

    Dooley, James J.

    2011-06-08

    This abstract and its accompanying presentation will provide an overview of two distinct industrial processes for removing carbon dioxide (CO2) from the atmosphere as a means of addressing anthropogenic climate change. The first of these is carbon dioxide capture and storage (CCS) coupled with large scale biomass production (hereafter referred to as bioCCS). The second is CO2 capture from ambient air via industrial systems (hereafter referred to as direct air capture (DAC)). In both systems, the captured CO2 would be injected into deep geologic formations so as to isolate it from the atmosphere. The technical literature is clear that both of these technologies are technically feasible as of today (IPCC, 2005; Keith, 2009; Lackner, 2009; Luckow et al., 2010; Ranjan and Herzog, 2011). What is uncertain is the relative cost of these industrial ambient-air CO2 removal systems when compared to other emissions mitigation measures, the ultimate timing and scale of their deployment, and the resolution of potential site specific constraints that would impact their ultimate commercial deployment.

  11. Use of hairy roots extracts for 2,4-DCP removal and toxicity evaluation by Lactuca sativa test.

    PubMed

    Angelini, Vanina A; Agostini, Elizabeth; Medina, María I; González, Paola S

    2014-02-01

    2,4-Dichlorophenol (2,4-DCP) is widely distributed in wastewaters discharged from several industries, and it is considered as a priority pollutant due to its high toxicity. In this study, the use of different peroxidase extracts for 2,4-DCP removal from aqueous solutions was investigated. Tobacco hairy roots (HRs), wild-type (WT), and double-transgenic (DT) for tomato basic peroxidases (TPX1 and TPX2) were used to obtain different peroxidase extracts: total peroxidases (TPx), soluble peroxidases (SPx), and peroxidases ionically bound to the cell wall (IBPx). All extracts derived from DT HRs exhibited higher peroxidase activity than those obtained from WT HRs. TPx and IBPx DT extracts showed the highest catalytic efficiency values. The optimal conditions for 2,4-DCP oxidation were pH 6.5, H2O2 0.5 mM, and 200 U mL(-1) of enzyme, for all extracts analyzed. Although both TPx extracts were able to oxidize different 2,4-DCP concentrations, the removal efficiency was higher for TPx DT. Polyethylene glycol addition slightly improved 2,4-DCP removal efficiency, and it showed some protective effect on TPx WT after 2,4-DCP oxidation. In addition, using Lactuca sativa test, a reduction of the toxicity of post removal solutions was observed, for both TPx extracts. The results demonstrate that TPx extracts from both tobacco HRs appear to be promising candidate for future applications in removing 2,4-DCP from wastewaters. This is particularly true considering that these peroxidase sources are associated with low costs and are readily available. However, TPx DT has increased peroxidase activity, catalytic efficiency, and higher removal efficiency than TPx WT, probably due to the expression of TPX1 and TPX2 isoenzymes.

  12. Studies with the USF/NASA toxicity screening test method - Effect of air flow and effect of fabric dye

    NASA Technical Reports Server (NTRS)

    Hilado, C. J.; Lopez, M. T.

    1976-01-01

    One sample each of commercial polyurethane and polychloroprene flexible foams were evaluated using the USF/NASA toxicity screening test method. Air flow rates of 0, 0.16, 16, and 48 ml/sec were used to determine the effect of air flow on relative toxicity. Time to first sign of incapacitation and time to death were substantially reduced with both polyurethane and polychloroprene flexible foams by the introduction of 16 to 48 ml/sec air flow. The relative toxicity rankings of these materials were not altered by changes in air flow. Under these test conditions, the polyurethane foam consistently appeared more toxic than the polychloroprene foam. Samples of six different colors from the same fabric were evaluated separately, using the USF/NASA toxicity screening test method, to determine the effect of fabric dye, if any. The material was an upholstery fabric, consisting of 46 percent cotton, 33 percent wool, and 21 percent nylon. There appeared to be no significant effect of fabric dye on relative toxicity, for this material under these test conditions.

  13. Removal potential of toxic 2378-substituted PCDD/F from incinerator flue gases by waste-derived activated carbons

    SciTech Connect

    Hajizadeh, Yaghoub; Onwudili, Jude A.; Williams, Paul T.

    2011-06-15

    The application of activated carbons has become a commonly used emission control protocol for the removal or adsorption of persistent organic pollutants from the flue gas streams of waste incinerators. In this study, the 2378-substituted PCDD/F removal efficiency of three types of activated carbons derived from the pyrolysis of refuse derived fuel, textile waste and scrap tyre was investigated and compared with that of a commercial carbon. Experiments were carried out in a laboratory scale fixed-bed reactor under a simulated flue gas at 275 deg. C with a reaction period of four days. The PCDD/F in the solid matrices and exhaust gas, were analyzed using gas chromatography coupled with a triple quadrupole mass spectrometer. In the absence of activated carbon adsorbent, there was a significant increase in the concentration of toxic PCDD/F produced in the reacted flyash, reaching up to 6.6 times higher than in the raw flyash. In addition, there was a substantial release of PCDD/F into the gas phase, which was found in the flue gas trapping system. By application of the different commercial, refuse derived fuel, textile and tyre activated carbons the total PCDD/F toxic equivalent removal efficiencies in the exhaust gas stream were 58%, 57%, 64% and 52%, respectively. In general, the removal of the PCDDs was much higher with an average of 85% compared to PCDFs at 41%. Analysis of the reacted activated carbons showed that there was some formation of PCDD/F, for instance, a total of 60.6 {mu}g I-TEQ kg{sup -1} toxic PCDD/F was formed in the refuse derived fuel activated carbon compared to 34 {mu}g I-TEQ kg{sup -1} in the commercial activated carbon. The activated carbons derived from the pyrolysis of waste, therefore, showed good potential as a control material for PCDD/F emissions in waste incinerator flue gases.

  14. Personal and ambient exposures to air toxics in Camden, New Jersey.

    PubMed

    Lioy, Paul J; Fan, Zhihua; Zhang, Junfeng; Georgopoulos, Panos; Wang, Sheng-Wei; Ohman-Strickland, Pamela; Wu, Xiangmei; Zhu, Xianlei; Harrington, Jason; Tang, Xiaogang; Meng, Qingyu; Jung, Kyung Hwa; Kwon, Jaymin; Hernandez, Marta; Bonnano, Linda; Held, Joann; Neal, John

    2011-08-01

    Personal exposures and ambient concentrations of air toxics were characterized in a pollution "hot spot" and an urban reference site, both in Camden, New Jersey. The hot spot was the city's Waterfront South neighborhood; the reference site was a neighborhood, about 1 km to the east, around the intersection of Copewood and Davis streets. Using personal exposure measurements, residential ambient air measurements, statistical analyses, and exposure modeling, we examined the impact of local industrial and mobile pollution sources, particularly diesel trucks, on personal exposures and ambient concentrations in the two neighborhoods. Presented in the report are details of our study design, sample and data collection methods, data- and model-analysis approaches, and results and key findings of the study. In summary, 107 participants were recruited from nonsmoking households, including 54 from Waterfront South and 53 from the Copewood-Davis area. Personal air samples were collected for 24 hr and measured for 32 target compounds--11 volatile organic compounds (VOCs*), four aldehydes, 16 polycyclic aromatic hydrocarbons (PAHs), and particulate matter (PM) with an aerodynamic diameter < or = 2.5 microm (PM2.5). Simultaneously with the personal monitoring, ambient concentrations of the target compounds were measured at two fixed monitoring sites, one each in the Waterfront South and Copewood-Davis neighborhoods. To understand the potential impact of local sources of air toxics on personal exposures caused by temporal (weekdays versus weekend days) and seasonal (summer versus winter) variations in source intensities of the air toxics, four measurements were made of each subject, two in summer and two in winter. Within each season, one measurement was made on a weekday and the other on a weekend day. A baseline questionnaire and a time diary with an activity questionnaire were administered to each participant in order to obtain information that could be used to understand

  15. Passive decay heat removal by natural air convection after severe accidents

    SciTech Connect

    Erbacher, F.J.; Neitzel, H.J.; Cheng, X.

    1995-09-01

    The composite containment proposed by the Research Center Karlsruhe and the Technical University Karlsruhe is to cope with severe accidents. It pursues the goal to restrict the consequences of core meltdown accidents to the reactor plant. One essential of this new containment concept is its potential to remove the decay heat by natural air convection and thermal radiation in a passive way. To investigate the coolability of such a passive cooling system and the physical phenomena involved, experimental investigations are carried out at the PASCO test facility. Additionally, numerical calculations are performed by using different codes. A satisfying agreement between experimental data and numerical results is obtained.

  16. Bio-active glass air-abrasion has the potential to remove resin composite restorative material selectively

    NASA Astrophysics Data System (ADS)

    Milly, Hussam; Andiappan, Manoharan; Thompson, Ian; Banerjee, Avijit

    2014-06-01

    The aims of this study were to assess: (a) the chemistry, morphology and bioactivity of bio-active glass (BAG) air-abrasive powder, (b) the effect of three air-abrasion operating parameters: air pressure, powder flow rate (PFR) and the abrasive powder itself, on the selective removal of resin composite and (c) the required “time taken”. BAG abrasive particles were characterised using scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDX) and Fourier-transform infrared spectroscopy (FTIR). Standardised resin composite restorations created within an enamel analogue block (Macor™) in vitro, were removed using air-abrasion undersimulated clinical conditions. 90 standardised cavities were scanned before and after resin composite removal using laser profilometry and the volume of the resulting 3D images calculated. Multilevel linear model was used to identify the significant factors affecting Macor™ removal. BAG powder removed resin composite more selectively than conventional air-abrasion alumina powder using the same operating parameters (p < 0.001) and the effect of altering the unit's operating parameters was significant (p < 0.001). In conclusion, BAG powder is more efficient than alumina in the selective removal of resin composite particularly under specific operating parameters, and therefore may be recommended clinically as a method of preserving sound enamel structure when repairing and removing defective resin composite restorations.

  17. An exploratory study of ambient air toxics exposure in pregnancy and the risk of neuroblastoma in offspring

    PubMed Central

    Heck, Julia E; Park, Andrew S.; Qiu, Jiaheng; Cockburn, Myles; Ritz, Beate

    2013-01-01

    Little is known about the etiology of neuroblastoma, the most common cancer in infancy. In this study, we examined maternal exposure to ambient air toxics in pregnancy in relation to neuroblastoma in the child. We ascertained all cases of neuroblastoma listed in the California Cancer Registry 1990-2007 that could be linked to a California birth certificate, and controls were selected at random from California birth records. Average air toxics exposures during pregnancy were determined based upon measures from community-based air pollution monitors. The study included 75 cases and 14,602 controls who lived with 5 kilometers of an air pollution monitor, and we additionally examined results for those living within a smaller radius around the monitor (2.5 km). Logistic regression was used to determine the risk of neuroblastoma with one interquartile range increase in air toxic exposure. Neuroblastoma risk was increased with higher maternal exposure to carbon tetrachloride (OR=2.65, 95%CI 1.07, 6.53) and polycyclic aromatic hydrocarbons (OR=1.39, 95%CI 1.05, 1.84), particularly indeno(1,2,3-cd)pyrene and dibenz(a,h)anthracene. Hexavalent chromium was associated with neuroblastoma at the 5 km distance (OR=1.32, 95%CI 1.00, 1.74) but not at the 2.5 km distance. This is one of the first studies to report associations between neuroblastoma and these air toxics. PMID:24139061

  18. Research into acetone removal from air by biofiltration using a biofilter with straight structure plates

    PubMed Central

    Baltrėnas, Pranas; Zagorskis, Alvydas; Misevičius, Antonas

    2015-01-01

    The biological air treatment method is based on the biological destruction of organic compounds using certain cultures of microorganisms. This method is simple and may be applied in many branches of industry. The main element of biological air treatment devices is a filter charge. Tests were carried out using a new-generation laboratory air purifier with a plate structure. This purifier is called biofilter. The biofilter has a special system for packing material humidification which does not require additional energy inputs. In order to extend the packing material's durability, it was composed of thermally treated birch fibre. Pollutant (acetone) biodegradation occurred on thermally treated wood fibre in this research. According to the performed tests and the received results, the process of biodestruction was highly efficient. When acetone was passed through biofilter's packing material at 0.08 m s−1 rate, the efficiency of the biofiltration process was from 70% up to 90%. The species of bacteria capable of removing acetone vapour from the air, i.e. Bacillus (B. cereus, B. subtilis), Pseudomonas (P. aeruginosa, P. putida), Stapylococcus (S. aureus) and Rhodococcus sp., was identified in this study during the process of biofiltration. Their amount in the biological packing material changed from 1.6 × 107 to 3.7 × 1011 CFU g−1. PMID:26019659

  19. Removal of fine and ultrafine particles from indoor air environments by the unipolar ion emission

    NASA Astrophysics Data System (ADS)

    Uk Lee, Byung; Yermakov, Mikhail; Grinshpun, Sergey A.

    2004-09-01

    The continuous emission of unipolar ions was evaluated in order to determine its ability to remove fine and ultrafine particles from indoor air environments. The evolution of the indoor aerosol concentration and particle size distribution was measured in real time with the ELPI in a room-size (24.3 m3) test chamber where the ion emitter was operating. After the results were compared with the natural decay, the air cleaning factor was determined. The particle aerodynamic size range of ∼0.04-2 μm was targeted because it represents many bioaerosol agents that cause emerging diseases, as well as those that can be used for biological warfare or in the event of bioterrorism. The particle electric charge distribution (also measured in the test chamber with the ELPI) was rapidly affected by the ion emission. It was concluded that the corona discharge ion emitters (either positive or negative), which are capable of creating an ion density of 105-106 e± cm-3, can be efficient in controlling fine and ultrafine aerosol pollutants in indoor air environments, such as a typical office or residential room. At a high ion emission rate, the particle mobility becomes sufficient so that the particle migration results in their deposition on the walls and other indoor surfaces. Within the tested ranges of the particle size and ion density, the particles were charged primarily due to the diffusion charging mechanism. The particle removal efficiency was not significantly affected by the particle size, while it increased with increasing ion emission rate and the time of emission. The performance characteristics of three commercially available ionic air purifiers, which produce unipolar ions by corona discharge at relatively high emission rates, were evaluated. A 30-minute operation of the most powerful device among those tested resulted in the removal of about 97% of 0.1 μm particles and about 95% of 1 μm particles from the air in addition to the natural decay effect.

  20. SITE EMERGING TECHNOLOGY SUMMARY. BIOSCRUBBER FOR REMOVING HAZARDOUS ORGANIC EMISSIONS FROM SOIL, WATER, AND AIR DECONTAMINATION PROCESSES

    EPA Science Inventory

    An advanced biofiltration system has been developed for the removal of trace organic contaminants in air. This bioscrubber uses activated carbon as a support for biogrowth. An advanced engineering design was incorporated into the bioscrubber to allow biomass removal and nutrient ...

  1. Fast removal of the antibiotic flumequine from aqueous solution by ozonation: Influencing factors, reaction pathways, and toxicity evaluation.

    PubMed

    Feng, Mingbao; Yan, Liqing; Zhang, Xiaoling; Sun, Ping; Yang, Shaogui; Wang, Liansheng; Wang, Zunyao

    2016-01-15

    As one of the first generation of fluoroquinolone antibiotics, flumequine (FLU) has been detected ubiquitously in surface waters and municipal wastewaters. In light of FLU's possible adverse effects on aquatic species, the removal of this antibiotic has received worldwide attention. In this study, the kinetics, transformation products, mechanisms and toxicity variations of the ozonation process for FLU were systematically determined. The possible effects of solution pH, addition of inorganic ions, dissolved organic matter, and tert-butyl-alcohol (a radical scavenger), as well as the type of water matrices on FLU removal by ozonation, were studied from the perspective of the degradation kinetics. The data obtained suggested that ozone can be used as an effective oxidant for the fast removal of FLU from natural waters. Using liquid chromatography-mass spectrometry, a total of thirteen transformation products of FLU during ozonation were identified, and their specific reaction mechanisms were also proposed. The degradation pathways involving the hydroxylation, decarboxylation and defluorination were tentatively proposed. Meanwhile, the generation of three low-molecular-weight carboxylic acids was also observed. In addition, the potential toxicity of the transformation mixtures of FLU by ozone was evaluated. Overall, this paper can be a unique contribution to the systematic elucidation of the ozonation process of this antibiotic in water. PMID:26409146

  2. Fast removal of the antibiotic flumequine from aqueous solution by ozonation: Influencing factors, reaction pathways, and toxicity evaluation.

    PubMed

    Feng, Mingbao; Yan, Liqing; Zhang, Xiaoling; Sun, Ping; Yang, Shaogui; Wang, Liansheng; Wang, Zunyao

    2016-01-15

    As one of the first generation of fluoroquinolone antibiotics, flumequine (FLU) has been detected ubiquitously in surface waters and municipal wastewaters. In light of FLU's possible adverse effects on aquatic species, the removal of this antibiotic has received worldwide attention. In this study, the kinetics, transformation products, mechanisms and toxicity variations of the ozonation process for FLU were systematically determined. The possible effects of solution pH, addition of inorganic ions, dissolved organic matter, and tert-butyl-alcohol (a radical scavenger), as well as the type of water matrices on FLU removal by ozonation, were studied from the perspective of the degradation kinetics. The data obtained suggested that ozone can be used as an effective oxidant for the fast removal of FLU from natural waters. Using liquid chromatography-mass spectrometry, a total of thirteen transformation products of FLU during ozonation were identified, and their specific reaction mechanisms were also proposed. The degradation pathways involving the hydroxylation, decarboxylation and defluorination were tentatively proposed. Meanwhile, the generation of three low-molecular-weight carboxylic acids was also observed. In addition, the potential toxicity of the transformation mixtures of FLU by ozone was evaluated. Overall, this paper can be a unique contribution to the systematic elucidation of the ozonation process of this antibiotic in water.

  3. Treatment of produced waters for removal of soluble organics and toxicity reduction using the GAC-FBR process

    SciTech Connect

    Sunday, A.; Cook, J.; Rajan, R.; Hickey, R.

    1995-12-31

    Pilot studies were conducted using 550 gallon per day biological Granular Activated Carbon-Fluidized Bed Reactor (GAC-FBR) systems to treat four different produced waters obtained from on-shore and off-shore production facilities. The organic and inorganic composition of these produced waters varied greatly from site to site. Total dissolved solids ranged from 0.8% to 18.5%; BTEX concentrations varied from 470 {mu}g/L to greater than 4500 {mu}g/L. Organic carbon concentrations of up to 440 mg/L were observed. Sulfide concentrations ranged from nil to greater than 800 mg/L as S. Organic loading rates up to 86.6 kgCOD/cu.m-day were applied to the GAC-FBR. Successful treatment was achieved at hydraulic retention times as low as 7 minutes. Essentially complete removal of BTEX and total volatile hydrocarbons was demonstrated for each of the produced water samples; significant removal of non-purgable dissolved organic carbon was also observed. Overall BTEX removals of >99.9% were consistently achieved. Results from several different toxicity assays indicated that the GAC-FBR was able to achieve complete reduction of toxicity with several of the produced waters tested.

  4. Whole house particle removal and clean air delivery rates for in-duct and portable ventilation systems.

    PubMed

    Macintosh, David L; Myatt, Theodore A; Ludwig, Jerry F; Baker, Brian J; Suh, Helen H; Spengler, John D

    2008-11-01

    A novel method for determining whole house particle removal and clean air delivery rates attributable to central and portable ventilation/air cleaning systems is described. The method is used to characterize total and air-cleaner-specific particle removal rates during operation of four in-duct air cleaners and two portable air-cleaning devices in a fully instrumented test home. Operation of in-duct and portable air cleaners typically increased particle removal rates over the baseline rates determined in the absence of operating a central fan or an indoor air cleaner. Removal rates of 0.3- to 0.5-microm particles ranged from 1.5 hr(-1) during operation of an in-duct, 5-in. pleated media filter to 7.2 hr(-1) for an in-duct electrostatic air cleaner in comparison to a baseline rate of 0 hr(-1) when the air handler was operating without a filter. Removal rates for total particulate matter less than 2.5 microm in aerodynamic diameter (PM2.5) mass concentrations were 0.5 hr(-1) under baseline conditions, 0.5 hr(-1) during operation of three portable ionic air cleaners, 1 hr(-1) for an in-duct 1-in. media filter, 2.4 hr(-1) for a single high-efficiency particle arrestance (HEPA) portable air cleaner, 4.6 hr(-1) for an in-duct 5-in. media filter, 4.7 hr(-1) during operation of five portable HEPA filters, 6.1 hr(-1) for a conventional in-duct electronic air cleaner, and 7.5 hr(-1) for a high efficiency in-duct electrostatic air cleaner. Corresponding whole house clean air delivery rates for PM2.5 attributable to the air cleaner independent of losses within the central ventilation system ranged from 2 m3/min for the conventional media filter to 32 m3/min for the high efficiency in-duct electrostatic device. Except for the portable ionic air cleaner, the devices considered here increased particle removal indoors over baseline deposition rates. PMID:19044163

  5. Nanofiber Air Filters with High-Temperature Stability for Efficient PM2.5 Removal from the Pollution Sources.

    PubMed

    Zhang, Rufan; Liu, Chong; Hsu, Po-Chun; Zhang, Chaofan; Liu, Nian; Zhang, Jinsong; Lee, Hye Ryoung; Lu, Yingying; Qiu, Yongcai; Chu, Steven; Cui, Yi

    2016-06-01

    Here, we developed high-efficiency (>99.5%) polyimide-nanofiber air filters for the high temperature PM2.5 removal. The polyimide nanofibers exhibited high thermal stability, and the PM2.5 removal efficiency was kept unchanged when temperature ranged from 25-370 °C. These filters had high air flux with very low pressure drop. They could continuously work for >120 h for PM2.5 index >300. A field-test showed that they could effectively remove >99.5% PM particles from car exhaust at high temperature.

  6. Thermal decomposition of captan and formation pathways of toxic air pollutants.

    PubMed

    Chen, Kai; Mackie, John C; Kennedy, Eric M; Dlugogorski, Bogdan Z

    2010-06-01

    This study investigates the thermal decomposition of a widely used fungicide, captan, under gas phase conditions, similar to those occurring in fires, cigarette burning, and combustion of biomass treated or contaminated with pesticides. The laboratory-scale apparatus consisted of a plug flow reactor equipped with sampling trains for gaseous, volatile organic compounds (VOC) and condensed products, with analysis performed by Fourier transform infrared spectroscopy (FTIR) and gas chromatography-mass spectrometry (GC-MS), respectively. Under oxidative conditions, the thermal decomposition of captan generated gaseous pollutants including carbon disulfide, thiophosgene, phosgene, and hydrogen cyanide. The VOC analysis revealed the formation of tetrachloroethylene, hexachloroethane, and benzonitrile. Quantum chemical calculations indicated that captan decomposes unimolecularly, via fission of the C-S bond, with the ensuing radicals reacting with O(2). The results of the present study provide an improved understanding of the formation pathways of toxic air pollutants in the accidental or deliberate combustion of captan.

  7. TOF-SIMS measurements for toxic air pollutants adsorbed on the surface of airborne particles

    NASA Astrophysics Data System (ADS)

    Tomiyasu, Bunbunoshin; Hoshi, Takahiro; Owari, Masanori; Nihei, Yoshimasa

    2003-01-01

    Three kinds of particulate matter were collected: diesel and gasoline exhaust particles emitted directly from exhaust nozzle, and suspended particulate matter (SPM) near the traffic route. Soxhlet extraction was performed on each sample. By gas-chromatograph-mass spectrometer (GC-MS) analysis of these extracts, di-ethyl phthalate and di- n-butyl phthalate were detected from the extract of SPM and diesel exhaust particles (DEPs). Because these phthalates were sometimes suspected as contamination, time-of-flight secondary ion mass spectrometry (TOF-SIMS) measurements were also performed on the samples collected at the same environment. By comparing obtained spectra, it is clear that these environmental endocrine disrupters (EEDs) were adsorbed on DEP surface. Thus, we concluded that the combination of conventional method and TOF-SIMS measurement is one of the most powerful techniques for analyzing the toxic air pollutants adsorbed on SPM surface.

  8. Γ-Al₂O₃-based nanocomposite adsorbents for arsenic(V) removal: assessing performance, toxicity and particle leakage.

    PubMed

    Onnby, Linda; Svensson, Christian; Mbundi, Lubinda; Busquets, Rosa; Cundy, Andrew; Kirsebom, Harald

    2014-03-01

    The generation and development of effective adsorption materials for arsenic removal are urgently needed due to acute arsenic contamination of water sources in many regions around the world. In the search for these new adsorbents, the application of nanomaterials or nanocomposites, and especially the use of nanoparticles (NPs), has proven increasingly attractive. While the adsorptive performance of a range of nanocomposite and nanomaterial-based systems has been extensively reviewed in previously-published literature, the stability of these systems in terms of NP release, i.e. the ability of the nanomaterial or nanocomposite to retain incorporated NPs, is less well understood. Here we examine the performance of nanocomposites comprised of aluminium oxide nanoparticles (AluNPs) incorporated in macroporous polyacrylamide-based cryogels (n-Alu-cryo, where n indicates the percentage of AluNPs in the polymer material (n=0-6%, w/v)) for As(V) adsorption, and evaluate AluNP leakage before and after the use of these materials. A range of techniques is utilised and assessed (SEM, TEM, mass weight change, PIXE and in vitro toxicity studies). The 4-Alu-cryo nanocomposite was shown to be optimal for minimising AluNP losses while maximising As(V) removal. From the same nanocomposite we were further able to show that NP losses were not detectable at the AluNP concentrations used in the study. Toxicity tests revealed that no cytotoxic effects could be observed. The cryogel-AluNPs composites were not only effective in As(V) removal but also in immobilising the AluNPs. More challenging flow-through conditions for the evaluation of NP leakage could be included as a next step in a continued study assessing particle loss and subsequent toxicity.

  9. Γ-Al₂O₃-based nanocomposite adsorbents for arsenic(V) removal: assessing performance, toxicity and particle leakage.

    PubMed

    Onnby, Linda; Svensson, Christian; Mbundi, Lubinda; Busquets, Rosa; Cundy, Andrew; Kirsebom, Harald

    2014-03-01

    The generation and development of effective adsorption materials for arsenic removal are urgently needed due to acute arsenic contamination of water sources in many regions around the world. In the search for these new adsorbents, the application of nanomaterials or nanocomposites, and especially the use of nanoparticles (NPs), has proven increasingly attractive. While the adsorptive performance of a range of nanocomposite and nanomaterial-based systems has been extensively reviewed in previously-published literature, the stability of these systems in terms of NP release, i.e. the ability of the nanomaterial or nanocomposite to retain incorporated NPs, is less well understood. Here we examine the performance of nanocomposites comprised of aluminium oxide nanoparticles (AluNPs) incorporated in macroporous polyacrylamide-based cryogels (n-Alu-cryo, where n indicates the percentage of AluNPs in the polymer material (n=0-6%, w/v)) for As(V) adsorption, and evaluate AluNP leakage before and after the use of these materials. A range of techniques is utilised and assessed (SEM, TEM, mass weight change, PIXE and in vitro toxicity studies). The 4-Alu-cryo nanocomposite was shown to be optimal for minimising AluNP losses while maximising As(V) removal. From the same nanocomposite we were further able to show that NP losses were not detectable at the AluNP concentrations used in the study. Toxicity tests revealed that no cytotoxic effects could be observed. The cryogel-AluNPs composites were not only effective in As(V) removal but also in immobilising the AluNPs. More challenging flow-through conditions for the evaluation of NP leakage could be included as a next step in a continued study assessing particle loss and subsequent toxicity. PMID:24370695

  10. Silent Discharge Plasma Technology for the Treatment of Air Toxics and Other Applications

    SciTech Connect

    Rosocha, Louis A.; Chase, Peter J.; Gross, Michael P.

    1998-09-21

    Under this CRADA, the Los Alamos National Laboratory (LANL) and High Mesa Technologies, Inc. (HMT) carried out a joint project on the development of the silent discharge plasma (SDP) technology for the treatment of hazardous air pollutants and other hazardous or toxic chemicals. The project had two major components: a technology-demonstration part and a scale-up and commercialization part. In the first part, a small-scale, mobile SDP plasma processor, which was being developed under a CRADA with the Electric Power Research Institute (EPRI) was the mobile equipment was modified for higher capacity service and employed for an innovative remediation technologies demonstration on soil-vapor extraction off-gases at the McClellan Air Force Base near Sacramento, CA. The performance of the SDP system for the variety of volatile organic compounds (VOCs) encountered at the McClellan site was sufficiently promising to the project HMT and LANL worked together to formulate a scale-up strategy and commercialization/manufacturing plan, and to design a prototype scaled-up SDP unit. HMT and LANL are now in the final stages of completing a licensing agreement for the technology and HMT is in the process of raising funds to engineer and manufacture commercial prototype SDP equipment focused on stack-gas emissions control and environmental remediation. HMT, in collaboration with another Northern New Mexico business, Coyote Aerospace, has also been successful in receiving a Phase I Small Business Innovative Research (SBIR) award from the Army Research Office to develop, design, and construct a small non-thermal plasma reactor for laboratory studies ("Non-Thermal Plasma Reactor for Control of Fugitive Emissions of Toxic Gases")

  11. Ecotoxicological studies of environmental samples from Buenos Aires area using a standardized amphibian embryo toxicity test (AMPHITOX).

    PubMed

    Herkovits, Jorge; Perez-Coll, Cristina; Herkovits, Francisco D

    2002-01-01

    The toxicity of 34 environmental samples from potentially polluted and reference stations were evaluated by means of the AMPHITOX test from acute to chronic exposure according to the toxicity found in each sample. The samples were obtained from surface and ground water, leaches, industrial effluents and soils. The data, expressed in acute, short-term chronic and chronic Toxicity Units (TUa, TUstc and TUc) resulted in a maximal value of 1000 TUc, found in a leach, while the lower toxicity value was 1.4 TUa corresponding to two surface water samples. In five samples (four providing from reference places) no toxicity was detected. The results point out the possibility of evaluating the toxicity of a wide diversity of samples by means of AMPHITOX as a customized toxicity test. The fact that almost all samples with suspected toxicity in rivers and streams from the Metropolitan area of Buenos Aires city resulted toxic, indicates the need of enhanced stewardship of chemical substances for environmental and human health protection purposes. PMID:11808551

  12. Novel Strategies for the Removal of Toxic Metals from Soils and Waters

    ERIC Educational Resources Information Center

    Roundhill, D. Max

    2004-01-01

    The elimination of poisonous metals possessing chemical or radioactive substances, from soils and waters, and chemistry's contribution towards efficacious and environmentally suitable removal methods are discussed. Various original tactics are studied and compared.

  13. Validation of an in vitro exposure system for toxicity assessment of air-delivered nanomaterials

    PubMed Central

    Kim, Jong Sung; Peters, Thomas M.; O’Shaughnessy, Patrick T.; Adamcakova-Dodd, Andrea; Thorne, Peter S.

    2013-01-01

    To overcome the limitations of in vitro exposure of submerged lung cells to nanoparticles (NPs), we validated an integrated low flow system capable of generating and depositing airborne NPs directly onto cells at an air–liquid interface (ALI). The in vitro exposure system was shown to provide uniform and controlled dosing of particles with 70.3% efficiency to epithelial cells grown on transwells. This system delivered a continuous airborne exposure of NPs to lung cells without loss of cell viability in repeated 4 h exposure periods. We sequentially exposed cells to air-delivered copper (Cu) NPs in vitro to compare toxicity results to our prior in vivo inhalation studies. The evaluation of cellular dosimetry indicated that a large amount of Cu was taken up, dissolved and released into the basolateral medium (62% of total mass). Exposure to Cu NPs decreased cell viability to 73% (p < 0.01) and significantly (p < 0.05) elevated levels of lactate dehydrogenase, intracellular reactive oxygen species and interleukin-8 that mirrored our findings from subacute in vivo inhalation studies in mice. Our results show that this exposure system is useful for screening of NP toxicity in a manner that represents cellular responses of the pulmonary epithelium in vivo. PMID:22981796

  14. Successful intervention in a child with toxic methemoglobinemia due to nail polish remover poisoning.

    PubMed

    Patra, Soumya; Sikka, Gurleen; Khaowas, Ajoy Kumar; Kumar, Virender

    2011-09-01

    Children are most susceptible to accidental exposure of common household substances and one of the common household substances is nail polish remover. We are presenting a case of accidental ingestion of nail polish remover with lethal methemoglobinemia (serum methemoglobin level-72%). This patient was treated successfully with injection methylene blue. However, even small amounts can be dangerous to children, so it is important to keep this and all household chemicals in a safe place. PMID:22412293

  15. Successful intervention in a child with toxic methemoglobinemia due to nail polish remover poisoning

    PubMed Central

    Patra, Soumya; Sikka, Gurleen; Khaowas, Ajoy Kumar; Kumar, Virender

    2011-01-01

    Children are most susceptible to accidental exposure of common household substances and one of the common household substances is nail polish remover. We are presenting a case of accidental ingestion of nail polish remover with lethal methemoglobinemia (serum methemoglobin level-72%). This patient was treated successfully with injection methylene blue. However, even small amounts can be dangerous to children, so it is important to keep this and all household chemicals in a safe place PMID:22412293

  16. Ultrafine particle removal by residential heating, ventilating, and air-conditioning filters.

    PubMed

    Stephens, B; Siegel, J A

    2013-12-01

    This work uses an in situ filter test method to measure the size-resolved removal efficiency of indoor-generated ultrafine particles (approximately 7-100 nm) for six new commercially available filters installed in a recirculating heating, ventilating, and air-conditioning (HVAC) system in an unoccupied test house. The fibrous HVAC filters were previously rated by the manufacturers according to ASHRAE Standard 52.2 and ranged from shallow (2.5 cm) fiberglass panel filters (MERV 4) to deep-bed (12.7 cm) electrostatically charged synthetic media filters (MERV 16). Measured removal efficiency ranged from 0 to 10% for most ultrafine particles (UFP) sizes with the lowest rated filters (MERV 4 and 6) to 60-80% for most UFP sizes with the highest rated filter (MERV 16). The deeper bed filters generally achieved higher removal efficiencies than the panel filters, while maintaining a low pressure drop and higher airflow rate in the operating HVAC system. Assuming constant efficiency, a modeling effort using these measured values for new filters and other inputs from real buildings shows that MERV 13-16 filters could reduce the indoor proportion of outdoor UFPs (in the absence of indoor sources) by as much as a factor of 2-3 in a typical single-family residence relative to the lowest efficiency filters, depending in part on particle size. PMID:23590456

  17. Ultrafine particle removal by residential heating, ventilating, and air-conditioning filters.

    PubMed

    Stephens, B; Siegel, J A

    2013-12-01

    This work uses an in situ filter test method to measure the size-resolved removal efficiency of indoor-generated ultrafine particles (approximately 7-100 nm) for six new commercially available filters installed in a recirculating heating, ventilating, and air-conditioning (HVAC) system in an unoccupied test house. The fibrous HVAC filters were previously rated by the manufacturers according to ASHRAE Standard 52.2 and ranged from shallow (2.5 cm) fiberglass panel filters (MERV 4) to deep-bed (12.7 cm) electrostatically charged synthetic media filters (MERV 16). Measured removal efficiency ranged from 0 to 10% for most ultrafine particles (UFP) sizes with the lowest rated filters (MERV 4 and 6) to 60-80% for most UFP sizes with the highest rated filter (MERV 16). The deeper bed filters generally achieved higher removal efficiencies than the panel filters, while maintaining a low pressure drop and higher airflow rate in the operating HVAC system. Assuming constant efficiency, a modeling effort using these measured values for new filters and other inputs from real buildings shows that MERV 13-16 filters could reduce the indoor proportion of outdoor UFPs (in the absence of indoor sources) by as much as a factor of 2-3 in a typical single-family residence relative to the lowest efficiency filters, depending in part on particle size.

  18. Pyrolysis of polymeric materials. I - Effect of chemical structure, temperature, heating rate, and air flow on char yield and toxicity

    NASA Technical Reports Server (NTRS)

    Hilado, C. J.; Casey, C. J.

    1979-01-01

    Various polymeric materials, including synthetic polymers and cellulosic materials, were evaluated at different temperatures, heating rates and air flow rates for thermophysical and toxicological responses. It is shown that char yields appeared to be a function of air access as much as of the chemical structure of the material. It is stated that the sensitivity of the apparent thermal stability of some materials to air access is so marked that thermogravimetric studies in oxygen-free atmospheres may be a consistently misleading approach to comparing synthetic polymers intended to increase fire safety. Toxicity also appeared to be a function of temperature and air access as much as of the chemical structure of the material. Toxicity of the gases evolved seemed to increase with increasing char yield for some polymers.

  19. Experimental treatment of a refinery waste air stream, for BTEX removal, by water scrubbing and biotrickling on a bed of Mitilus edulis shells.

    PubMed

    Torretta, Vincenzo; Collivignarelli, Maria Cristina; Raboni, Massimo; Viotti, Paolo

    2015-01-01

    The paper presents the results of a two-stage pilot plant for the removal of benzene, toluene, ethylbenzene and xylene (BTEX) from a waste air stream of a refinery wastewater treatment plant (WWTP). The pilot plant consisted of a water scrubber followed by a biotrickling filter (BTF). The exhausted air was drawn from the main works of the WWTP in order to prevent the free migration to the atmosphere of these volatile hazardous contaminants. Concentrations were detected at average values of 12.4 mg Nm(-3) for benzene, 11.1 mg Nm(-3) for toluene, 2.7 mg Nm(-3) for ethylbenzene and 9.5 mg Nm(-3) for xylene, with considerable fluctuation mainly for benzene and toluene (peak concentrations of 56.8 and 55.0 mg Nm(-3), respectively). The two treatment stages proved to play an effective complementary task: the water scrubber demonstrated the ability to remove the concentration peaks, whereas the BTF was effective as a polishing stage. The overall average removal efficiency achieved was 94.8% while the scrubber and BTF elimination capacity were 37.8 and 15.6 g BTEX d(-1) m(-3), respectively. This result has led to outlet average concentrations of 1.02, 0.25, 0.32 and 0.26 mg Nm(-3) for benzene, toluene, ethylbenzene and xylene, respectively. The paper also compares these final concentrations with toxic and odour threshold concentrations.

  20. Ozonation of oil sands process water removes naphthenic acids and toxicity.

    PubMed

    Scott, Angela C; Zubot, Warren; MacKinnon, Michael D; Smith, Daniel W; Fedorak, Phillip M

    2008-03-01

    Naphthenic acids are naturally-occurring, aliphatic or alicyclic carboxylic acids found in petroleum. Water used to extract bitumen from the Athabasca oil sands becomes toxic to various organisms due to the presence of naphthenic acids released from the bitumen. Natural biodegradation was expected to be the most cost-effective method for reducing the toxicity of the oil sands process water (OSPW). However, naphthenic acids are poorly biodegraded in the holding ponds located on properties leased by the oil sands companies. In the present study, chemical oxidation using ozone was investigated as an option for mitigation of this toxicity. Ozonation of sediment-free OSPW was conducted using proprietary technology manufactured by Seair Diffusion Systems Inc. Ozonation for 50min generated a non-toxic effluent (based on the Microtox bioassay) and decreased the naphthenic acids concentration by approximately 70%. After 130min of ozonation, the residual naphthenic acids concentration was 2mgl(-1): <5% of the initial concentration in the filtered OSPW. Total organic carbon did not change with 130min of ozonation, whereas chemical oxygen demand decreased by approximately 50% and 5-d biochemical oxygen demand increased from an initial value of 2mgl(-1) to a final value of 15mgl(-1). GC-MS analysis showed that ozonation resulted in an overall decrease in the proportion of high molecular weight naphthenic acids (n> or = 22).

  1. Effectiveness of in situ air sparging for removing NAPL gasoline from a sandy aquifer near Perth, Western Australia.

    PubMed

    Johnston, C D; Rayner, J L; Briegel, D

    2002-11-01

    In situ air sparging has the potential to augment the removal of nonaqueous phase liquid (NAPL) contaminants in soil vapour extraction (SVE) systems when the NAPL is present in the capillary fringe or below the water table. NAPL removal can also be enhanced from above the water table by improving air access. Results are presented from a pilot-scale field trial aimed at evaluating the performance of such a remediation strategy where in situ air sparging was used in conjunction with a soil vapour extraction system to remove weathered gasoline NAPL from an unconfined sandy aquifer. A simple analysis that partitions extracted soil vapour between air injected through the sparge well and air drawn from the atmosphere across the soil surface, together with petroleum hydrocarbon concentrations in the extracted soil vapour, was used to interpret the effectiveness of air sparging. The composition and mass of the NAPL in the aquifer were also monitored along with observations on the distribution of air in the aquifer. Results showed that sparged air constituted 42% of the extracted soil vapour but contributed the majority of the petroleum hydrocarbons removed. For the first 5 days of sparging, hydrocarbon concentrations in the sparged air were in equilibrium with the NAPL in the aquifer leading to total petroleum hydrocarbon concentrations in the combined system being three to four times greater than for soil vapour extraction alone. Petroleum hydrocarbon concentrations in the extracted soil vapour decreased over time as a result of the depletion of the more volatile constituents from the NAPL, possible development of mass transfer limitations and increased fraction of clean air from depleted zones. Overall, 65% of the 673 kg of petroleum hydrocarbons extracted in soil vapour over a period of 30 days was carried in sparged air from the single sparge well. Percentages of the mass carried in the sparged air were even higher (median 70%) for individual aromatic hydrocarbons

  2. Two-dimensional titanium carbide for efficiently reductive removal of highly toxic chromium(VI) from water.

    PubMed

    Ying, Yulong; Liu, Yu; Wang, Xinyu; Mao, Yiyin; Cao, Wei; Hu, Pan; Peng, Xinsheng

    2015-01-28

    Two dimensional (2-D) Ti3C2Tx nanosheets are obtained by etching bulk Ti3C2Tx powders in HF solution and delaminating ultrasonically, which exhibit excellent removal capacity for toxic Cr(VI) from water, due to their high surface area, well dispersibility, and reductivity. The Ti3C2Tx nanosheets delaminated by 10% HF solution present more efficient Cr(VI) removal performance with capacity of 250 mg g(-1), and the residual concentration of Cr(VI) in treated water is less than 5 ppb, far below the concentration (0.05 ppm) of Cr(VI) in the drinking water standard recommended by the World Health Organization. This kind of 2-D Ti3C2Tx nanosheet can not only remove Cr(VI) rapidly and effectively in one step from aqueous solution by reducing Cr(VI) to Cr(III) but also adsorb the reduced Cr(III) simultaneously. Furthermore, these reductive 2-D Ti3C2Tx nanosheets are generally explored to remove other oxidant agents, such as K3[Fe(CN)6], KMnO4, and NaAuCl4 solutions, by converting them to low oxidation states. These significantly expand the potential applications of 2-D Ti3C2Tx nanosheets in water treatment. PMID:25559042

  3. Personal and ambient exposures to air toxics in Camden, New Jersey.

    PubMed

    Lioy, Paul J; Fan, Zhihua; Zhang, Junfeng; Georgopoulos, Panos; Wang, Sheng-Wei; Ohman-Strickland, Pamela; Wu, Xiangmei; Zhu, Xianlei; Harrington, Jason; Tang, Xiaogang; Meng, Qingyu; Jung, Kyung Hwa; Kwon, Jaymin; Hernandez, Marta; Bonnano, Linda; Held, Joann; Neal, John

    2011-08-01

    Personal exposures and ambient concentrations of air toxics were characterized in a pollution "hot spot" and an urban reference site, both in Camden, New Jersey. The hot spot was the city's Waterfront South neighborhood; the reference site was a neighborhood, about 1 km to the east, around the intersection of Copewood and Davis streets. Using personal exposure measurements, residential ambient air measurements, statistical analyses, and exposure modeling, we examined the impact of local industrial and mobile pollution sources, particularly diesel trucks, on personal exposures and ambient concentrations in the two neighborhoods. Presented in the report are details of our study design, sample and data collection methods, data- and model-analysis approaches, and results and key findings of the study. In summary, 107 participants were recruited from nonsmoking households, including 54 from Waterfront South and 53 from the Copewood-Davis area. Personal air samples were collected for 24 hr and measured for 32 target compounds--11 volatile organic compounds (VOCs*), four aldehydes, 16 polycyclic aromatic hydrocarbons (PAHs), and particulate matter (PM) with an aerodynamic diameter < or = 2.5 microm (PM2.5). Simultaneously with the personal monitoring, ambient concentrations of the target compounds were measured at two fixed monitoring sites, one each in the Waterfront South and Copewood-Davis neighborhoods. To understand the potential impact of local sources of air toxics on personal exposures caused by temporal (weekdays versus weekend days) and seasonal (summer versus winter) variations in source intensities of the air toxics, four measurements were made of each subject, two in summer and two in winter. Within each season, one measurement was made on a weekday and the other on a weekend day. A baseline questionnaire and a time diary with an activity questionnaire were administered to each participant in order to obtain information that could be used to understand

  4. Reduction in acute toxicity of soils to terrestrial oligochaetes following the removal of bioavailable polycyclic aromatic hydrocarbons with mild supercritical carbon dioxide extraction.

    PubMed

    Hawthorne, Steven B; Lanno, Roman; Kreitinger, Joseph P

    2005-08-01

    Three soil samples contaminated with polycyclic aromatic hydrocarbons (PAHs) that caused 100% mortality to terrestrial oligochaetes were extracted with supercritical carbon dioxide to remove the bioavailable fraction of PAHs. Although the remaining PAH concentrations were high after supercritical fluid extraction (SFE), 650 to 8,000 mg/kg, acute toxicity to Eisenia fetida and Enchytraeus albidus essentially was eliminated. These results demonstrate that mild SFE with pure carbon dioxide preferentially extracts PAH molecules that are bioavailable toxicologically to the oligochaetes, although biologically unavailable PAHs are not extracted, suggesting that SFE could be used for the removal of toxicity due to hydrophobic organic chemicals in soils during toxicity identification evaluations.

  5. DIESEL TRUCK IDLING EMISSIONS - MOBILE SOURCE AIR TOXICS MEASURED AT A HOT SPOT

    SciTech Connect

    Parks, II, James E; Storey, John Morse; Miller, Terry L.; Fu, Joshua S.; Hromis, Boris

    2007-01-01

    Mobile Source Air Toxics (MSATs) are of growing concern due to recent studies linking health risk to residency near heavily traveled roadways. Few research studies on MSAT emissions have been performed due to several factors; those factors include: the difficulty of measuring MSATs due to their semi-volatile nature, lower relative concentration in comparison to NOx and other criteria emissions, and fewer regulations on MSATs. In this paper, measurements of MSATs at a "hot spot" of poor air quality created by a high population of idling heavy-duty trucks are presented. The study area was the Watt Road-Interstate-40/75 interchange just west of Knoxville, TN where approximately 20,000 heavy-duty trucks travel along the interstate each day and hundreds of heavy-duty trucks idle at three large truck stops near the interchange. The air quality in the local area surrounding the interchange is affected negatively by the high number of mobile sources as well as geographic and meteorological conditions; the interchange lies in a valley between two ridges which slows long range transport of pollutants especially in winter months when temperature inversion occurs frequently. Ambient air quality was measured during summer and winter months of two separate years at three sites: a site in one of the truckstops, a site near the interstate roadway, and a site on top of one of the surrounding ridges chosen as a background site for comparison. Results of criteria pollutants measured at these sites are reported in a companion paper by Miller et. al.; the results presented here include measurements of MSATs such as formaldehyde, acetaldehyde, acrolein, and other species obtained via collection on di-nitrophenyl hydrazine (DNPH) filters. Also, preliminary measurements of poly-aromatic hydrocarbons are presented. The results indicate that emissions from idling heavy-duty trucks are a primary contributor of MSATs to local air quality near areas of high static truck traffic; furthermore

  6. Assessment of Sociodemographic and Geographic Disparities in Cancer Risk from Air Toxics in South Carolina

    PubMed Central

    Wilson, Sacoby; Burwell-Naney, Kristen; Jiang, Chengsheng; Zhang, Hongmei; Samantapudi, Ashok; Murray, Rianna; Dalemarre, Laura; Rice, LaShanta; Williams, Edith

    2015-01-01

    Populations of color and low-income communities are often disproportionately burdened by exposures to various environmental contaminants, including air pollution. Some air pollutants have carcinogenic properties that are particularly problematic in South Carolina (SC), a state that consistently has high rates of cancer mortality for all sites. The purpose of this study was to assess cancer risk disparities in SC by linking risk estimates from the U.S. Environmental Protection Agency’s 2005 National Air Toxics Assessment (NATA) with sociodemographic data from the 2000 US Census Bureau. Specifically, NATA risk data for varying risk categories were linked by tract ID and analyzed with sociodemographic variables from the 2000 census using R. The average change in cancer risk from all sources by sociodemographic variable was quantified using multiple linear regression models. Spatial methods were further employed using ArcGIS 10 to assess the distribution of all source risk and percent non-white at each census tract level. The relative risk estimates of the proportion of high cancer risk tracts (defined as the top 10% of cancer risk in SC) and their respective 95% confidence intervals (CIs) were calculated between the first and latter three quartiles defined by sociodemographic factors, while the variance in the percentage of high cancer risk between quartile groups was tested using Pearson’s chi-square. The average total cancer risk for SC was 26.8 people/million (ppl/million). The risk from on-road sources was approximately 5.8 ppl/million, higher than the risk from major, area, and non-road sources (1.8, 2.6, and 1.3 ppl/million), respectively. Based on our findings, addressing on-road sources may decrease the disproportionate cancer risk burden among low-income populations and communities of color in SC. PMID:26037107

  7. Assessment of sociodemographic and geographic disparities in cancer risk from air toxics in South Carolina.

    PubMed

    Wilson, Sacoby; Burwell-Naney, Kristen; Jiang, Chengsheng; Zhang, Hongmei; Samantapudi, Ashok; Murray, Rianna; Dalemarre, Laura; Rice, LaShanta; Williams, Edith

    2015-07-01

    Populations of color and low-income communities are often disproportionately burdened by exposures to various environmental contaminants, including air pollution. Some air pollutants have carcinogenic properties that are particularly problematic in South Carolina (SC), a state that consistently has high rates of cancer mortality for all sites. The purpose of this study was to assess cancer risk disparities in SC by linking risk estimates from the U.S. Environmental Protection Agency's 2005 National Air Toxics Assessment (NATA) with sociodemographic data from the 2000 US Census Bureau. Specifically, NATA risk data for varying risk categories were linked by tract ID and analyzed with sociodemographic variables from the 2000 census using R. The average change in cancer risk from all sources by sociodemographic variable was quantified using multiple linear regression models. Spatial methods were further employed using ArcGIS 10 to assess the distribution of all source risk and percent non-white at each census tract level. The relative risk (RR) estimates of the proportion of high cancer risk tracts (defined as the top 10% of cancer risk in SC) and their respective 95% confidence intervals (CIs) were calculated between the first and latter three quartiles defined by sociodemographic factors, while the variance in the percentage of high cancer risk between quartile groups was tested using Pearson's chi-square. The average total cancer risk for SC was 26.8 people/million (ppl/million). The risk from on-road sources was approximately 5.8 ppl/million, higher than the risk from major, area, and non-road sources (1.8, 2.6, and 1.3 ppl/million), respectively. Based on our findings, addressing on-road sources may decrease the disproportionate cancer risk burden among low-income populations and communities of color in SC.

  8. Assessment of sociodemographic and geographic disparities in cancer risk from air toxics in South Carolina.

    PubMed

    Wilson, Sacoby; Burwell-Naney, Kristen; Jiang, Chengsheng; Zhang, Hongmei; Samantapudi, Ashok; Murray, Rianna; Dalemarre, Laura; Rice, LaShanta; Williams, Edith

    2015-07-01

    Populations of color and low-income communities are often disproportionately burdened by exposures to various environmental contaminants, including air pollution. Some air pollutants have carcinogenic properties that are particularly problematic in South Carolina (SC), a state that consistently has high rates of cancer mortality for all sites. The purpose of this study was to assess cancer risk disparities in SC by linking risk estimates from the U.S. Environmental Protection Agency's 2005 National Air Toxics Assessment (NATA) with sociodemographic data from the 2000 US Census Bureau. Specifically, NATA risk data for varying risk categories were linked by tract ID and analyzed with sociodemographic variables from the 2000 census using R. The average change in cancer risk from all sources by sociodemographic variable was quantified using multiple linear regression models. Spatial methods were further employed using ArcGIS 10 to assess the distribution of all source risk and percent non-white at each census tract level. The relative risk (RR) estimates of the proportion of high cancer risk tracts (defined as the top 10% of cancer risk in SC) and their respective 95% confidence intervals (CIs) were calculated between the first and latter three quartiles defined by sociodemographic factors, while the variance in the percentage of high cancer risk between quartile groups was tested using Pearson's chi-square. The average total cancer risk for SC was 26.8 people/million (ppl/million). The risk from on-road sources was approximately 5.8 ppl/million, higher than the risk from major, area, and non-road sources (1.8, 2.6, and 1.3 ppl/million), respectively. Based on our findings, addressing on-road sources may decrease the disproportionate cancer risk burden among low-income populations and communities of color in SC. PMID:26037107

  9. Laccase-catalyzed removal of the antimicrobials chlorophene and dichlorophen from water: Reaction kinetics, pathway and toxicity evaluation.

    PubMed

    Shi, Huanhuan; Peng, Jianbiao; Li, Jianhua; Mao, Liang; Wang, Zunyao; Gao, Shixiang

    2016-11-01

    As active agents in cleaning and disinfecting products, antimicrobials have been widely spread in the environment and have drawn extensive attention as potential threats to the ecological system and human health. In this study, the laccase-catalyzed removal of two emerging antimicrobials, chlorophene (CP) and dichlorophen (DCP), was investigated under simulated environmental conditions. Intrinsic reaction kinetics showed that the removal of CP and DCP followed second-order reaction kinetics, first-order with respect to both the enzyme and the substrate concentration. It was also found that fulvic acid could suppress the transformation of CP and DCP by reversing the oxidation reactions through its action as a scavenger of the free radical intermediates produced from reactions between laccase and the substrates. Several reaction products were identified by a quadrupole time-of-flight mass spectrometer, and detailed reaction pathways were proposed. For both CP and DCP, direct polymerization was the principal pathway, and the coupling patterns were further corroborated based on molecular modeling. The nucleophilic substitution of chlorine by the hydroxyl group was observed, and further oxidation products capable of coupling with each other were also found. Additionally, toxicity evaluation tests using Scenedesmus obliquus confirmed that the toxicity of CP and DCP was effectively eliminated during the reaction processes.

  10. Laccase-catalyzed removal of the antimicrobials chlorophene and dichlorophen from water: Reaction kinetics, pathway and toxicity evaluation.

    PubMed

    Shi, Huanhuan; Peng, Jianbiao; Li, Jianhua; Mao, Liang; Wang, Zunyao; Gao, Shixiang

    2016-11-01

    As active agents in cleaning and disinfecting products, antimicrobials have been widely spread in the environment and have drawn extensive attention as potential threats to the ecological system and human health. In this study, the laccase-catalyzed removal of two emerging antimicrobials, chlorophene (CP) and dichlorophen (DCP), was investigated under simulated environmental conditions. Intrinsic reaction kinetics showed that the removal of CP and DCP followed second-order reaction kinetics, first-order with respect to both the enzyme and the substrate concentration. It was also found that fulvic acid could suppress the transformation of CP and DCP by reversing the oxidation reactions through its action as a scavenger of the free radical intermediates produced from reactions between laccase and the substrates. Several reaction products were identified by a quadrupole time-of-flight mass spectrometer, and detailed reaction pathways were proposed. For both CP and DCP, direct polymerization was the principal pathway, and the coupling patterns were further corroborated based on molecular modeling. The nucleophilic substitution of chlorine by the hydroxyl group was observed, and further oxidation products capable of coupling with each other were also found. Additionally, toxicity evaluation tests using Scenedesmus obliquus confirmed that the toxicity of CP and DCP was effectively eliminated during the reaction processes. PMID:27262275

  11. Assessment of toxicity reduction after metal removal in bioleached sewage sludge.

    PubMed

    Renoux, A Y; Tyagi, R D; Samson, R

    2001-04-01

    Sewage sludge can be applied to land to supply and recycle organic matter and nutrients. Trace elements in sludge, however, may accumulate in the soil with repeated sludge applications. Reducing metal content may therefore reduce the adverse effects of sludge application. The objective of this study was to evaluate the efficiency of bioleaching technology in reducing metal content and toxicity as measured by a battery of terrestrial and liquid-phase bioassays. Sludge-soil mixtures simulating the application of sludge to land were tested by means of terrestrial bioassays, barley (Hordeum vulgare L.) seed germination (5 d) and sprout growth (14 d), lettuce (Lactuca sativa) seed germination (5 d), and worm (Eisenia andrei) mortality (14 d). Liquid-phase bioassays, Microtox (Vibrio fischeri, 15 min), lettuce root elongation (L. sativa, 5 d), cladoceran mortality (Daphnia magna, 48 h), and SOS Chromotest (Escherichia coli) were used after elutriation of the sludge. Comparison of the bioassay results (except for D. magna) before and after treatment demonstrated that this bioleaching process reduced both sludge toxicity and metal content. In addition, lower Cu and Zn concentrations found in barley sprouts following treatment supported the assumption that the bioleaching process, by decreasing metal content and bioavailability, reduced sewage sludge toxicity. This study also emphasized the interest of using ecotoxicological bioassays for testing biosolids. In particular, the terrestrial bioassays after simulation of land application and the Microtox test after sludge elutriation proved to be the most appropriate procedures. PMID:11317888

  12. Geographic boundaries in breast, lung and colorectal cancers in relation to exposure to air toxics in Long Island, New York

    PubMed Central

    Jacquez, Geoffrey M; Greiling, Dunrie A

    2003-01-01

    Background This two-part study employs several statistical techniques to evaluate the geographic distribution of breast cancer in females and colorectal and lung cancers in males and females in Nassau, Queens, and Suffolk counties, New York, USA. In this second paper, we compare patterns in standardized morbidity ratios (SMR values), calculated from New York State Department of Health (NYSDOH) data, to geographic patterns in overall predicted risk (OPR) from air toxics using exposures estimated in the USEPA National Air Toxics Assessment database. Results We identified significant geographic boundaries in SMR and OPR. We found little or no association between the SMR of colorectal and breast cancers and the OPR for each cancer from exposure to the air toxics. We did find boundaries in male and female lung cancer SMR and boundaries in lung cancer OPR to be closer to one another than expected. Conclusion While consistent with a causal relationship between air toxics and lung cancer incidence, the boundary analysis does not demonstrate the existence of a causal relationship. However, now that the areas of overlap between boundaries in lung cancer incidence and potential airborne exposures have been identified, we can begin to evaluate local- as well as large-scale determinants of lung cancer. PMID:12633502

  13. PREVENTION REFERENCE MANUAL: CONTROL TECHNOLOGIES, VOL. 2. POST-RELEASE MITIGATION MEASURES FOR CONTROLLING ACCIDENTAL RELEASES OF AIR TOXICS

    EPA Science Inventory

    The volume discusses prevention and protection measures for controlling accidental releases of air toxics. The probability of accidental releases depends on the extent to which deviations (in magnitude and duration) in the process can be tolerated before a loss of chemical contai...

  14. CHANGES IN HEART RATE VARIABILITY AND LUNG FUNCTION OBSERVED IN NC PATROL TROOPERS EXPOSED TO PM AND AIR TOXICS

    EPA Science Inventory

    Changes in Heart Rate Variability and Lung Function in NC Patrol Troopers exposed to PM and Air Toxics

    Michael Riediker1, Wayne E Cascio1, Robert B Devlin2, Thomas Griggs1&4, Margaret Herbst1, Ronald W Williams3, Steve P McCorquodale4, Philip A Bromberg1
    1) University o...

  15. SPATIAL AND TEMPORAL VARIABILITY OF MOBILE SOURCE AIR TOXICS IN THE DETROIT EXPOSURE AND AEROSOL RESEARCH STUDY

    EPA Science Inventory

    Data from the first two years of the Detroit Exposure and Aerosol Research Study (DEARS) were evaluated to determine spatial and temporal characteristics in concentrations of mobile source air toxics (MSATs). Outdoor concentrations of MSATs were significantly higher in samples co...

  16. Air Toxics under the Big Sky: A Real-World Investigation to Engage High School Science Students

    ERIC Educational Resources Information Center

    Adams, Earle; Smith, Garon; Ward, Tony J.; Vanek, Diana; Marra, Nancy; Jones, David; Henthorn, Melissa; Striebel, Jim

    2008-01-01

    This paper describes a problem-based chemistry education model in which students perform scientific research on a local environmentally relevant problem. The project is a collaboration among The University of Montana and local high schools centered around Missoula, Montana. "Air Toxics under the Big Sky" involves high school students in collecting…

  17. Relationship of Racial Composition and Cancer Risks from Air Toxics Exposure in Memphis, Tennessee, U.S.A.

    PubMed Central

    Jia, Chunrong; James, Wesley; Kedia, Satish

    2014-01-01

    African Americans in the U.S. often live in poverty and segregated urban neighborhoods, many of which have dense industrial facilities resulting in high exposure to harmful air toxics. This study aims to explore the relationship between racial composition and cancer risks from air toxics exposure in Memphis/Shelby County, Tennessee, U.S.A. Air toxics data were obtained from 2005 National Air Toxics Assessment (NATA), and the demographic data, including racial composition, were extracted from the 2000 United States Census. The association was examined using multivariable geographically weighted regression (GWR) analysis. The risk difference between African American and White concentrated areas was defined as the absolute disparity, and the percent difference as the relative disparity. GWR analyses show that cancer risks increase with respect to increasing percent of African Americans at the census tract level. Individuals in African American concentrated tracts bear 6% more cancer risk burden than in White concentrated tracts. The distribution of major roads causes the largest absolute disparity and the distribution of industrial facilities causes the largest relative disparity. Effective strategies for reduction in environmental disparity should especially target sources of large absolute disparities. PMID:25089776

  18. Design of an optimized biomixture for the degradation of carbofuran based on pesticide removal and toxicity reduction of the matrix.

    PubMed

    Chin-Pampillo, Juan Salvador; Ruiz-Hidalgo, Karla; Masís-Mora, Mario; Carazo-Rojas, Elizabeth; Rodríguez-Rodríguez, Carlos E

    2015-12-01

    Pesticide biopurification systems contain a biologically active matrix (biomixture) responsible for the accelerated elimination of pesticides in wastewaters derived from pest control in crop fields. Biomixtures have been typically prepared using the volumetric composition 50:25:25 (lignocellulosic substrate/humic component/soil); nonetheless, formal composition optimization has not been performed so far. Carbofuran is an insecticide/nematicide of high toxicity widely employed in developing countries. Therefore, the composition of a highly efficient biomixture (composed of coconut fiber, compost, and soil, FCS) for the removal of carbofuran was optimized by means of a central composite design and response surface methodology. The volumetric content of soil and the ratio coconut fiber/compost were used as the design variables. The performance of the biomixture was assayed by considering the elimination of carbofuran, the mineralization of (14)C-carbofuran, and the residual toxicity of the matrix, as response variables. Based on the models, the optimal volumetric composition of the FCS biomixture consists of 45:13:42 (coconut fiber/compost/soil), which resulted in minimal residual toxicity and ∼99% carbofuran elimination after 3 days. This optimized biomixture considerably differs from the standard 50:25:25 composition, which remarks the importance of assessing the performance of newly developed biomixtures during the design of biopurification systems.

  19. Design of an optimized biomixture for the degradation of carbofuran based on pesticide removal and toxicity reduction of the matrix.

    PubMed

    Chin-Pampillo, Juan Salvador; Ruiz-Hidalgo, Karla; Masís-Mora, Mario; Carazo-Rojas, Elizabeth; Rodríguez-Rodríguez, Carlos E

    2015-12-01

    Pesticide biopurification systems contain a biologically active matrix (biomixture) responsible for the accelerated elimination of pesticides in wastewaters derived from pest control in crop fields. Biomixtures have been typically prepared using the volumetric composition 50:25:25 (lignocellulosic substrate/humic component/soil); nonetheless, formal composition optimization has not been performed so far. Carbofuran is an insecticide/nematicide of high toxicity widely employed in developing countries. Therefore, the composition of a highly efficient biomixture (composed of coconut fiber, compost, and soil, FCS) for the removal of carbofuran was optimized by means of a central composite design and response surface methodology. The volumetric content of soil and the ratio coconut fiber/compost were used as the design variables. The performance of the biomixture was assayed by considering the elimination of carbofuran, the mineralization of (14)C-carbofuran, and the residual toxicity of the matrix, as response variables. Based on the models, the optimal volumetric composition of the FCS biomixture consists of 45:13:42 (coconut fiber/compost/soil), which resulted in minimal residual toxicity and ∼99% carbofuran elimination after 3 days. This optimized biomixture considerably differs from the standard 50:25:25 composition, which remarks the importance of assessing the performance of newly developed biomixtures during the design of biopurification systems. PMID:26250812

  20. Degradation and acute toxicity removal of the antidepressant Fluoxetine (Prozac(®)) in aqueous systems by electron beam irradiation.

    PubMed

    Silva, Vanessa Honda Ogihara; Dos Santos Batista, Ana Paula; Silva Costa Teixeira, Antonio Carlos; Borrely, Sueli Ivone

    2016-06-01

    Electron beam irradiation (EBI) has been considered an advanced technology for the treatment of water and wastewater, whereas very few previous investigations reported its use for removing pharmaceutical pollutants. In this study, the degradation of fluoxetine (FLX), an antidepressant marketed as Prozac(®), was investigated by using EBI at FLX initial concentration of 19.4 ± 0.2 mg L(-1). More than 90 % FLX degradation was achieved at 0.5 kGy, with FLX below the detection limit (0.012 mg L(-1)) at doses higher than 2.5 kGy. The elucidation of organic byproducts performed using direct injection mass spectrometry, along with the results of ion chromatography, indicated hydroxylation of FLX molecules with release of fluoride and nitrate anions. Nevertheless, about 80 % of the total organic carbon concentration remained even for 7.5 kGy or higher doses. The decreases in acute toxicity achieved 86.8 and 9.6 % for Daphnia similis and Vibrio fischeri after EBI exposure at 5 kGy, respectively. These results suggest that EBI could be an alternative to eliminate FLX and to decrease residual toxicity from wastewater generated in pharmaceutical formulation facilities, although further investigation is needed for correlating the FLX degradation mechanism with the toxicity results. PMID:26961524

  1. Experimental investigation of the formaldehyde removal mechanisms in a dynamic botanical filtration system for indoor air purification.

    PubMed

    Wang, Zhiqiang; Pei, Jingjing; Zhang, Jensen S

    2014-09-15

    Botanical filtration has been proved to be effective for indoor gas pollutant removal. To understand the roles of different transport, storage and removal mechanism by a dynamic botanical air filter, a series of experimental investigations were designed and conducted in this paper. Golden Pothos (Epipremnum aureum) plants was selected for test, and its original soil or activated/pebbles root bed was used in different test cases. It was found that flowing air through the root bed with microbes dynamically was essential to obtain meaningful formaldehyde removal efficiency. For static potted plant as normally place in rooms, the clean air delivery rate (CADR), which is often used to quantify the air cleaning ability of portable air cleaners, was only ∼ 5.1m(3)/h per m(2) bed, while when dynamically with air flow through the bed, the CADR increased to ∼ 233 m(3)/h per m(2) bed. The calculated CADR due to microbial activity is ∼ 108 m(3)/h per m(2) bed. Moisture in the root bed also played an important role, both for maintaining a favorable living condition for microbes and for absorbing water-soluble compounds such as formaldehyde. The role of the plant was to introduce and maintain a favorable microbe community which effectively degraded the volatile organic compounds adsorbed or absorbed by the root bed. The presence of the plant increased the removal efficiency by a factor of two based on the results from the bench-scale root bed experiments.

  2. Experimental investigation of the formaldehyde removal mechanisms in a dynamic botanical filtration system for indoor air purification.

    PubMed

    Wang, Zhiqiang; Pei, Jingjing; Zhang, Jensen S

    2014-09-15

    Botanical filtration has been proved to be effective for indoor gas pollutant removal. To understand the roles of different transport, storage and removal mechanism by a dynamic botanical air filter, a series of experimental investigations were designed and conducted in this paper. Golden Pothos (Epipremnum aureum) plants was selected for test, and its original soil or activated/pebbles root bed was used in different test cases. It was found that flowing air through the root bed with microbes dynamically was essential to obtain meaningful formaldehyde removal efficiency. For static potted plant as normally place in rooms, the clean air delivery rate (CADR), which is often used to quantify the air cleaning ability of portable air cleaners, was only ∼ 5.1m(3)/h per m(2) bed, while when dynamically with air flow through the bed, the CADR increased to ∼ 233 m(3)/h per m(2) bed. The calculated CADR due to microbial activity is ∼ 108 m(3)/h per m(2) bed. Moisture in the root bed also played an important role, both for maintaining a favorable living condition for microbes and for absorbing water-soluble compounds such as formaldehyde. The role of the plant was to introduce and maintain a favorable microbe community which effectively degraded the volatile organic compounds adsorbed or absorbed by the root bed. The presence of the plant increased the removal efficiency by a factor of two based on the results from the bench-scale root bed experiments. PMID:25164387

  3. Graphene-Based Microbots for Toxic Heavy Metal Removal and Recovery from Water.

    PubMed

    Vilela, Diana; Parmar, Jemish; Zeng, Yongfei; Zhao, Yanli; Sánchez, Samuel

    2016-04-13

    Heavy metal contamination in water is a serious risk to the public health and other life forms on earth. Current research in nanotechnology is developing new nanosystems and nanomaterials for the fast and efficient removal of pollutants and heavy metals from water. Here, we report graphene oxide-based microbots (GOx-microbots) as active self-propelled systems for the capture, transfer, and removal of a heavy metal (i.e., lead) and its subsequent recovery for recycling purposes. Microbots' structure consists of nanosized multilayers of graphene oxide, nickel, and platinum, providing different functionalities. The outer layer of graphene oxide captures lead on the surface, and the inner layer of platinum functions as the engine decomposing hydrogen peroxide fuel for self-propulsion, while the middle layer of nickel enables external magnetic control of the microbots. Mobile GOx-microbots remove lead 10 times more efficiently than nonmotile GOx-microbots, cleaning water from 1000 ppb down to below 50 ppb in 60 min. Furthermore, after chemical detachment of lead from the surface of GOx-microbots, the microbots can be reused. Finally, we demonstrate the magnetic control of the GOx-microbots inside a microfluidic system as a proof-of-concept for automatic microbots-based system to remove and recover heavy metals.

  4. Graphene-Based Microbots for Toxic Heavy Metal Removal and Recovery from Water

    PubMed Central

    2016-01-01

    Heavy metal contamination in water is a serious risk to the public health and other life forms on earth. Current research in nanotechnology is developing new nanosystems and nanomaterials for the fast and efficient removal of pollutants and heavy metals from water. Here, we report graphene oxide-based microbots (GOx-microbots) as active self-propelled systems for the capture, transfer, and removal of a heavy metal (i.e., lead) and its subsequent recovery for recycling purposes. Microbots’ structure consists of nanosized multilayers of graphene oxide, nickel, and platinum, providing different functionalities. The outer layer of graphene oxide captures lead on the surface, and the inner layer of platinum functions as the engine decomposing hydrogen peroxide fuel for self-propulsion, while the middle layer of nickel enables external magnetic control of the microbots. Mobile GOx-microbots remove lead 10 times more efficiently than nonmotile GOx-microbots, cleaning water from 1000 ppb down to below 50 ppb in 60 min. Furthermore, after chemical detachment of lead from the surface of GOx-microbots, the microbots can be reused. Finally, we demonstrate the magnetic control of the GOx-microbots inside a microfluidic system as a proof-of-concept for automatic microbots-based system to remove and recover heavy metals. PMID:26998896

  5. Graphene-Based Microbots for Toxic Heavy Metal Removal and Recovery from Water.

    PubMed

    Vilela, Diana; Parmar, Jemish; Zeng, Yongfei; Zhao, Yanli; Sánchez, Samuel

    2016-04-13

    Heavy metal contamination in water is a serious risk to the public health and other life forms on earth. Current research in nanotechnology is developing new nanosystems and nanomaterials for the fast and efficient removal of pollutants and heavy metals from water. Here, we report graphene oxide-based microbots (GOx-microbots) as active self-propelled systems for the capture, transfer, and removal of a heavy metal (i.e., lead) and its subsequent recovery for recycling purposes. Microbots' structure consists of nanosized multilayers of graphene oxide, nickel, and platinum, providing different functionalities. The outer layer of graphene oxide captures lead on the surface, and the inner layer of platinum functions as the engine decomposing hydrogen peroxide fuel for self-propulsion, while the middle layer of nickel enables external magnetic control of the microbots. Mobile GOx-microbots remove lead 10 times more efficiently than nonmotile GOx-microbots, cleaning water from 1000 ppb down to below 50 ppb in 60 min. Furthermore, after chemical detachment of lead from the surface of GOx-microbots, the microbots can be reused. Finally, we demonstrate the magnetic control of the GOx-microbots inside a microfluidic system as a proof-of-concept for automatic microbots-based system to remove and recover heavy metals. PMID:26998896

  6. GIS modeling of air toxics releases from TRI-reporting and non-TRI-reporting facilities: impacts for environmental justice.

    PubMed

    Dolinoy, Dana C; Miranda, Marie Lynn

    2004-12-01

    The Toxics Release Inventory (TRI) requires facilities with 10 or more full-time employees that process > 25,000 pounds in aggregate or use > 10,000 pounds of any one TRI chemical to report releases annually. However, little is known about releases from non-TRI-reporting facilities, nor has attention been given to the very localized equity impacts associated with air toxics releases. Using geographic information systems and industrial source complex dispersion modeling, we developed methods for characterizing air releases from TRI-reporting as well as non-TRI-reporting facilities at four levels of geographic resolution. We characterized the spatial distribution and concentration of air releases from one representative industry in Durham County, North Carolina (USA). Inclusive modeling of all facilities rather than modeling of TRI sites alone significantly alters the magnitude and spatial distribution of modeled air concentrations. Modeling exposure receptors at more refined levels of geographic resolution reveals localized, neighborhood-level exposure hot spots that are not apparent at coarser geographic scales. Multivariate analysis indicates that inclusive facility modeling at fine levels of geographic resolution reveals exposure disparities by income and race. These new methods significantly enhance the ability to model air toxics, perform equity analysis, and clarify conflicts in the literature regarding environmental justice findings. This work has substantial implications for how to structure TRI reporting requirements, as well as methods and types of analysis that will successfully elucidate the spatial distribution of exposure potentials across geographic, income, and racial lines. PMID:15579419

  7. Effectiveness of photocatalytic filter for removing volatile organic compounds in the heating, ventilation, and air conditioning system.

    PubMed

    Yu, Kuo-Pin; Lee, Grace Whei-May; Huang, Wei-Ming; Wu, Chih-Cheng; Lou, Chia-ling; Yang, Shinhao

    2006-05-01

    Nowadays, the heating, ventilation, and air conditioning (HVAC) system has been an important facility for maintaining indoor air quality. However, the primary function of typical HVAC systems is to control the temperature and humidity of the supply air. Most indoor air pollutants, such as volatile organic compounds (VOCs), cannot be removed by typical HVAC systems. Thus, some air handling units for removing VOCs should be added in typical HVAC systems. Among all of the air cleaning techniques used to remove indoor VOCs, photocatalytic oxidation is an attractive alternative technique for indoor air purification and deodorization. The objective of this research is to investigate the VOC removal efficiency of the photocatalytic filter in a HVAC system. Toluene and formaldehyde were chosen as the target pollutants. The experiments were conducted in a stainless steel chamber equipped with a simplified HVAC system. A mechanical filter coated with Degussa P25 titania photocatalyst and two commercial photocatalytic filters were used as the photocatalytic filters in this simplified HVAC system. The total air change rates were controlled at 0.5, 0.75, 1, 1.25, and 1.5 hr(-1), and the relative humidity (RH) was controlled at 30%, 50%, and 70%. The ultraviolet lamp used was a 4-W, ultraviolet-C (central wavelength at 254 nm) strip light bulb. The first-order decay constant of toluene and formaldehyde found in this study ranged from 0.381 to 1.01 hr(-1) under different total air change rates, from 0.34 to 0.433 hr(-1) under different RH, and from 0.381 to 0.433 hr(-1) for different photocatalytic filters.

  8. Development of an activated carbon filter to remove NO2 and HONO in indoor air.

    PubMed

    Yoo, Jun Young; Park, Chan Jung; Kim, Ki Yeong; Son, Youn-Suk; Kang, Choong-Min; Wolfson, Jack M; Jung, In-Ha; Lee, Sung-Joo; Koutrakis, Petros

    2015-05-30

    To obtain the optimum removal efficiency of NO2 and HONO by coated activated carbon (ACs), the influencing factors, including the loading rate, metal and non-metal precursors, and mixture ratios, were investigated. The NOx removal efficiency (RE) for K, with the same loading (1.0 wt.%), was generally higher than for those loaded with Cu or Mn. The RE of NO2 was also higher when KOH was used as the K precursor, compared to other K precursors (KI, KNO3, and KMnO4). In addition, the REs by the ACs loaded with K were approximately 38-55% higher than those by uncoated ACs. Overall, the REs (above 95%) of HONO and NOx with 3% KOH were the highest of the coated AC filters that were tested. Additionally, the REs of NOx and HONO using a mixing ratio of 6 (2.5% PABA (p-aminobenzoic acid)+6% H3PO4):4 (3% KOH) were the highest of all the coatings tested (both metal and non-metal). The results of this study show that AC loaded with various coatings has the potential to effectively reduce NO2 and HONO levels in indoor air.

  9. Development of an activated carbon filter to remove NO2 and HONO in indoor air.

    PubMed

    Yoo, Jun Young; Park, Chan Jung; Kim, Ki Yeong; Son, Youn-Suk; Kang, Choong-Min; Wolfson, Jack M; Jung, In-Ha; Lee, Sung-Joo; Koutrakis, Petros

    2015-05-30

    To obtain the optimum removal efficiency of NO2 and HONO by coated activated carbon (ACs), the influencing factors, including the loading rate, metal and non-metal precursors, and mixture ratios, were investigated. The NOx removal efficiency (RE) for K, with the same loading (1.0 wt.%), was generally higher than for those loaded with Cu or Mn. The RE of NO2 was also higher when KOH was used as the K precursor, compared to other K precursors (KI, KNO3, and KMnO4). In addition, the REs by the ACs loaded with K were approximately 38-55% higher than those by uncoated ACs. Overall, the REs (above 95%) of HONO and NOx with 3% KOH were the highest of the coated AC filters that were tested. Additionally, the REs of NOx and HONO using a mixing ratio of 6 (2.5% PABA (p-aminobenzoic acid)+6% H3PO4):4 (3% KOH) were the highest of all the coatings tested (both metal and non-metal). The results of this study show that AC loaded with various coatings has the potential to effectively reduce NO2 and HONO levels in indoor air. PMID:25725340

  10. Large Animal Model of Pumpless Arteriovenous Extracorporeal CO₂ Removal Using Room Air via Subclavian Vessels.

    PubMed

    Witer, Lucas J; Howard, Ryan A; Trahanas, John M; Bryner, Benjamin S; Alghanem, Fares; Hoffman, Hayley R; Cornell, Marie S; Bartlett, Robert H; Rojas-Peña, Alvaro

    2016-01-01

    End-stage lung disease (ESLD) causes progressive hypercapnia and dyspnea and impacts quality of life. Many extracorporeal support (ECS) configurations for CO2 removal resolve symptoms but limit ambulation. An ovine model of pumpless ECS using subclavian vessels was developed to allow for ambulatory support. Vascular grafts were anastomosed to the left subclavian vessels in four healthy sheep. A low-resistance membrane oxygenator was attached in an arteriovenous (AV) configuration. Device function was evaluated in each animal while awake and spontaneously breathing and while mechanically ventilated with hypercapnia induced. Sweep gas (FiO2 = 0.21) to the device was increased from 0 to 15 L/min, and arterial and postdevice blood gases, as well as postdevice air, were sampled. Hemodynamics remained stable with average AV shunt flows of 1.34 ± 0.14 L/min. In awake animals, CO2 removal was 3.4 ± 1.0 ml/kg/min at maximum sweep gas flow. Respiratory rate decreased from 60 ± 25 at baseline to 30 ± 11 breaths per minute. In animals with induced hypercapnia, PaCO2 increased to 73.9 ± 15.1. At maximum sweep gas flow, CO2 removal was 3.4 ± 0.4 ml/kg/min and PaCO2 decreased to 49.1 ± 6.7 mm Hg. Subclavian AV access is effective in lowering PaCO2 and respiratory rate and is potentially an effective ambulatory destination therapy for ESLD patients.

  11. Made-to-order metal-organic frameworks for trace carbon dioxide removal and air capture

    PubMed Central

    Shekhah, Osama; Belmabkhout, Youssef; Chen, Zhijie; Guillerm, Vincent; Cairns, Amy; Adil, Karim; Eddaoudi, Mohamed

    2014-01-01

    Direct air capture is regarded as a plausible alternate approach that, if economically practical, can mitigate the increasing carbon dioxide emissions associated with two of the main carbon polluting sources, namely stationary power plants and transportation. Here we show that metal-organic framework crystal chemistry permits the construction of an isostructural metal-organic framework (SIFSIX-3-Cu) based on pyrazine/copper(II) two-dimensional periodic 44 square grids pillared by silicon hexafluoride anions and thus allows further contraction of the pore system to 3.5 versus 3.84 Å for the parent zinc(II) derivative. This enhances the adsorption energetics and subsequently displays carbon dioxide uptake and selectivity at very low partial pressures relevant to air capture and trace carbon dioxide removal. The resultant SIFSIX-3-Cu exhibits uniformly distributed adsorption energetics and offers enhanced carbon dioxide physical adsorption properties, uptake and selectivity in highly diluted gas streams, a performance, to the best of our knowledge, unachievable with other classes of porous materials. PMID:24964404

  12. Made-to-order metal-organic frameworks for trace carbon dioxide removal and air capture.

    PubMed

    Shekhah, Osama; Belmabkhout, Youssef; Chen, Zhijie; Guillerm, Vincent; Cairns, Amy; Adil, Karim; Eddaoudi, Mohamed

    2014-06-25

    Direct air capture is regarded as a plausible alternate approach that, if economically practical, can mitigate the increasing carbon dioxide emissions associated with two of the main carbon polluting sources, namely stationary power plants and transportation. Here we show that metal-organic framework crystal chemistry permits the construction of an isostructural metal-organic framework (SIFSIX-3-Cu) based on pyrazine/copper(II) two-dimensional periodic 4(4) square grids pillared by silicon hexafluoride anions and thus allows further contraction of the pore system to 3.5 versus 3.84 Å for the parent zinc(II) derivative. This enhances the adsorption energetics and subsequently displays carbon dioxide uptake and selectivity at very low partial pressures relevant to air capture and trace carbon dioxide removal. The resultant SIFSIX-3-Cu exhibits uniformly distributed adsorption energetics and offers enhanced carbon dioxide physical adsorption properties, uptake and selectivity in highly diluted gas streams, a performance, to the best of our knowledge, unachievable with other classes of porous materials.

  13. Bioaugmentation with isolated strains for the removal of toxic and refractory organics from coking wastewater in a membrane bioreactor.

    PubMed

    Zhu, Xiaobiao; Liu, Rui; Liu, Cong; Chen, Lujun

    2015-11-01

    The bioaugmentation strains for phenol, pyridine, quinoline, carbazole, and naphthalene degradation were employed to treat coking wastewater in a membrane bioreactor (MBR). The results showed that the bioaugmented MBR was much better in pollutant removal than that of the control MBR with conventional activated sludge. Compared to the control MBR, the bioaugmented MBR displayed an additional 3.2 mg/L of phenol, pyridine, quinoline, naphthalene and carbazole in total by the addition of the degrading strains. Also, about 10 % of the chemical oxygen demand in the effluent was further removed by the bioaugmentation. The pyrosequencing analysis of the sludge in the MBRs revealed that the microbial community shifted in response to the addition of the degrading strains. The diversity of the microbial community increased during the bioaugmentation, and some bacterial taxa favorable to the removal of toxic and refractory pollutants appeared in the bioaugmented MBR. The results indicated that the use of high-efficiency bacteria was a feasible method for industrial coking wastewater treatment. PMID:26510738

  14. Excellent performance of copper based metal organic framework in adsorptive removal of toxic sulfonamide antibiotics from wastewater.

    PubMed

    Azhar, Muhammad Rizwan; Abid, Hussein Rasool; Sun, Hongqi; Periasamy, Vijay; Tadé, Moses O; Wang, Shaobin

    2016-09-15

    The increasing concerns on toxicity of sulfonamide antibiotics in water require a prompt action to establish efficient wastewater treatment processes for their removal. In this study, adsorptive removal of a model sulfonamide antibiotic, sulfachloropyridazine (SCP), from wastewater is presented for the first time using a metal organic framework (MOF). A high surface area and thermally stable MOF, HKUST-1, was synthesized by a facile method. Batch adsorption studies were systematically carried out using HKUST-1. The high surface area and unsaturated metal sites resulted in a significant adsorption capacity with faster kinetics. Most of the SCP was removed in 15min and the kinetic data were best fitted with the pseudo second order model. Moreover, isothermal data were best fitted with the Langmuir model. The thermodynamic results showed that the adsorption is a spontaneous and endothermic process. The adsorption capacity of HKUST-1 is 384mg/g at 298K which is the highest compared to most of the materials for the antibiotics. The high adsorption capacity is attributed mainly to π-π stacking, hydrogen bonding and electrostatic interactions. PMID:27318714

  15. Toxicity and removal of heavy metals (cadmium, copper, and zinc) by Lemna gibba.

    PubMed

    Megateli, Smain; Semsari, Saida; Couderchet, Michel

    2009-09-01

    Effects of cadmium, copper, and zinc on the aquatic plant Lemna gibba were determined under controlled conditions; in parallel their removal from the growth medium was followed. The results showed that the three heavy metals affected growth, a physiological stress index defined as the ratio of Chlorophyll to phaeophytin (D665/D665a), and the contents of proline. After 4 days, 10(-3)-10(-1)mg/L Cd inhibited growth by 25-100%, reduced D665/D665a by 35-89%, and increased proline content by 44-567%. Under the same conditions, 10(-4)-10(-1) microg/L Cu inhibited growth by 36-75%, reduced D665/D665a by 19-81%, and increased proline content by 67-288%. Comparable concentrations of Zn had little effect. However, higher concentrations (4, 30, and 50mg/L) inhibited growth by 50-79%. Also, 0.1 and 30 mg/L induced a small reduction of D665/D665a (-3.8% and -22%) and an increase in proline contents (+144% and +177%). When it was observed, proline accumulation was always transient and the maximum was reached after 4 days. Monitoring metal concentration in the medium showed that L. gibba was able to remove metals from the medium. Zn and Cu removal was biphasic, it was rapid during the first 2 days (> 60% reduction) and slow (10-20%) during the following 8 days. For Cd, removal was linear and depended on the initial concentration. It reached approximately 90% after 6 or 8 days for initial concentrations of 10(-1) and 10(-3)mg/L, respectively. PMID:19505721

  16. The importance of toxicity in determining the impact of hazardous air pollutants on the respiratory health of children in Tennessee.

    PubMed

    Moore, Roberta J H; Hotchkiss, Julie L

    2016-09-01

    Respiratory diseases, exacerbated through point source pollution, are currently among the leading causes of hospitalization of children in the United States. This paper investigates the relationship between the proximity of hazardous air pollutants (HAPs) emitted from Toxic Release Inventory (TRI) facilities and the number of children diagnosed in hospitals with a respiratory disease in Tennessee. The importance of controlling for toxicity of those HAPs is of particular interest. Hospital discharge, socioeconomic, TRI emission, and HAP toxicity data are used to estimate, via Generalized Linear Methods, a logistic regression model describing the relationship between the percent of children living in a zip code area treated for respiratory illness and the average annual emissions over the previous 10 years of HAPs from TRI sites in that area. Controlling for area socioeconomic characteristics, we find that accounting for toxicity is important in uncovering the relationship between HAP emissions and respiratory health of children. A one standard deviation increase in toxicity-weighted emissions per 100 square miles is associated with an increase in the number of children diagnosed with asthma (chronic bronchitis) by about 1205 (260). The evidence suggests that, with a goal to improving children's respiratory health, monitoring the toxicity of chemicals being emitted is at least as important as simply monitoring total emission levels. This suggests that the EPA should consider making efforts toward establishing toxicity adjusted emission guidelines. PMID:27342000

  17. Precombustion removal of hazardous air pollutant precursors. Technical progress report, July 1, 1996--September 30, 1996

    SciTech Connect

    1996-09-19

    This project involves the development of an optimized, bench-scale processing circuit capable of efficiently removing trace elements from run-of-mine coals. The optimized circuit will be developed using characterization data obtained from detailed washability studies and release analyses tests conducted with several eastern U.S. coals. The optimized circuit will incorporate a variety of conventional and advanced coal cleaning processes. The coal products from the optimized circuit will be further treated with complexing agents specifically designed to extract organometallic trace elements that are difficult to remove by physical cleaning operations. Finally, innovative bioremediation schemes will be investigated as a means of controlling the release of trace elements from the process waste streams. Emphasis has been placed on the development of a processing circuit which (i) maximizes the rejection of trace elements, (ii) minimizes the production of coal fines which are costly to process and less marketable, and (iii) minimizes the downstream impacts of the process waste on the environment. During the past quarter, several key subtasks were completed. Most of the characterization tests for the Pittsburgh No. 8 coal have now been concluded. These include all activities associated with Subtasks 3.2 washability analysis, 3.3 flotation release analysis, and 3.4 SEM/image analysis. A large portion of the bench-scale test work was also completed during the past quarter for the Pittsburgh No. 8 coal under Subtask 4.1 heavy media testing. Additional bench-scale tests are underway as outlined in Subtask 4.2 froth flotation and 4.3 enhanced gravity separation. Finally, experiments conducted under Subtasks 6.1 analysis of pond toxics and 6.2 control method evaluation using samples of refuse from the Pittsburgh No. 8 seam indicate that significant reductions (up to 90%) in trace element content can be achieved through the application of microbial mats.

  18. Biofiltration control of VOC and air toxic emissions: n-Butane and benzene

    SciTech Connect

    Allen, E.R.

    1996-12-31

    n-Butane and benzene vapors are routinely observed in urban atmospheres. Their presence in urban airsheds is of concern because of their ozone production potential as volatile organic compounds (VOCs) and/or potential toxicity. Also, these saturated hydrocarbons are representative of airborne aliphatic and aromatic compounds. Separate laboratory studies have been conducted on the biological elimination of n-butane (n-C{sub 4}H{sub 10}) and benzene (C{sub 6}H{sub 6}) from airstreams using treated compost biofilters. The removal efficiencies were found to exceed 90% for a conditioned biofilter medium and pollutant low concentrations (< 25 ppm) and zeroth order kinetics at higher concentrations (> 100 ppm), whereas benzene vapor elimination followed zeroth order kinetics at concentrations up to 200 ppm. The maximum n-butane and benzene elimination capacities observed for the compost biofilters and conditions employed were 25 and 70 g pollutant m{sup -3} h{sup -1}, respectively. 13 refs., 6 figs., 2 tabs.

  19. Enhanced removal of VOCs from aquifers during air sparging using thickeners and surfactants: Bench-scale experiments.

    PubMed

    Kim, Heonki; Ahn, Dayoung; Annable, Michael D

    2016-01-01

    The effects of controlled air flow paths during air sparging on the removal of volatile organic compounds were examined in this study using a two-dimensional bench-scale physical model. An aqueous solution of sodium carboxymethylcellulose (SCMC), which is a thickener, was used to increase the resistance of water to displacement by injected air in a region around the targeted zone. At the same time, an aqueous solution of sodium dodecylbenzene sulfonate (SDBS), which is a surfactant, was used to reduce the air entry pressure to enhance the air flow through the targeted region. Trichloroethene (TCE), dissolved in water, was used to represent an aqueous phase volatile organic compound (VOC). A binary mixture of perchloroethene (PCE) and n-hexane was also used as a nonaqeous phase liquid (NAPL). Controlled air flow through the source zone, achieved by emplacing a high viscosity aqueous solution into a region surrounding the TCE-impacted zone, resulted in increased TCE removal from 23.0% (control) to 38.2% during a 2.5h period. When the air flow was focused on the targeted source zone of aqueous phase TCE (by decreasing the surface tension within the source zone and its vicinity by 28 dyn/cm, no SCMC applied), the mass removal of TCE was enhanced to 41.3% during the same time period. With SCMC and SDBS applied simultaneously around and beneath a NAPL source zone, respectively, the NAPL components were found to be removed more effectively over a period of 8.2h than the sparging experiment with no additives applied; 84.6% of PCE and 94.0% of n-hexane were removed for the controlled air flow path experiments (with both SCMC and SDBS applied) compared to 52.7% (PCE) and 74.0% (n-hexane) removal for the control experiment (no additives applied). Based on the experimental observations made in this study, applying a viscous aqueous solution around the source zone and a surfactant solution in and near the source zone, the air flow was focused through the targeted contaminant

  20. Enhanced removal of VOCs from aquifers during air sparging using thickeners and surfactants: Bench-scale experiments.

    PubMed

    Kim, Heonki; Ahn, Dayoung; Annable, Michael D

    2016-01-01

    The effects of controlled air flow paths during air sparging on the removal of volatile organic compounds were examined in this study using a two-dimensional bench-scale physical model. An aqueous solution of sodium carboxymethylcellulose (SCMC), which is a thickener, was used to increase the resistance of water to displacement by injected air in a region around the targeted zone. At the same time, an aqueous solution of sodium dodecylbenzene sulfonate (SDBS), which is a surfactant, was used to reduce the air entry pressure to enhance the air flow through the targeted region. Trichloroethene (TCE), dissolved in water, was used to represent an aqueous phase volatile organic compound (VOC). A binary mixture of perchloroethene (PCE) and n-hexane was also used as a nonaqeous phase liquid (NAPL). Controlled air flow through the source zone, achieved by emplacing a high viscosity aqueous solution into a region surrounding the TCE-impacted zone, resulted in increased TCE removal from 23.0% (control) to 38.2% during a 2.5h period. When the air flow was focused on the targeted source zone of aqueous phase TCE (by decreasing the surface tension within the source zone and its vicinity by 28 dyn/cm, no SCMC applied), the mass removal of TCE was enhanced to 41.3% during the same time period. With SCMC and SDBS applied simultaneously around and beneath a NAPL source zone, respectively, the NAPL components were found to be removed more effectively over a period of 8.2h than the sparging experiment with no additives applied; 84.6% of PCE and 94.0% of n-hexane were removed for the controlled air flow path experiments (with both SCMC and SDBS applied) compared to 52.7% (PCE) and 74.0% (n-hexane) removal for the control experiment (no additives applied). Based on the experimental observations made in this study, applying a viscous aqueous solution around the source zone and a surfactant solution in and near the source zone, the air flow was focused through the targeted contaminant

  1. Enhanced removal of VOCs from aquifers during air sparging using thickeners and surfactants: Bench-scale experiments

    NASA Astrophysics Data System (ADS)

    Kim, Heonki; Ahn, Dayoung; Annable, Michael D.

    2016-01-01

    The effects of controlled air flow paths during air sparging on the removal of volatile organic compounds were examined in this study using a two-dimensional bench-scale physical model. An aqueous solution of sodium carboxymethylcellulose (SCMC), which is a thickener, was used to increase the resistance of water to displacement by injected air in a region around the targeted zone. At the same time, an aqueous solution of sodium dodecylbenzene sulfonate (SDBS), which is a surfactant, was used to reduce the air entry pressure to enhance the air flow through the targeted region. Trichloroethene (TCE), dissolved in water, was used to represent an aqueous phase volatile organic compound (VOC). A binary mixture of perchloroethene (PCE) and n-hexane was also used as a nonaqeous phase liquid (NAPL). Controlled air flow through the source zone, achieved by emplacing a high viscosity aqueous solution into a region surrounding the TCE-impacted zone, resulted in increased TCE removal from 23.0% (control) to 38.2% during a 2.5 h period. When the air flow was focused on the targeted source zone of aqueous phase TCE (by decreasing the surface tension within the source zone and its vicinity by 28 dyn/cm, no SCMC applied), the mass removal of TCE was enhanced to 41.3% during the same time period. With SCMC and SDBS applied simultaneously around and beneath a NAPL source zone, respectively, the NAPL components were found to be removed more effectively over a period of 8.2 h than the sparging experiment with no additives applied; 84.6% of PCE and 94.0% of n-hexane were removed for the controlled air flow path experiments (with both SCMC and SDBS applied) compared to 52.7% (PCE) and 74.0% (n-hexane) removal for the control experiment (no additives applied). Based on the experimental observations made in this study, applying a viscous aqueous solution around the source zone and a surfactant solution in and near the source zone, the air flow was focused through the targeted contaminant

  2. Removal of pollutants and reduction of bio-toxicity in a full scale chemical coagulation and reverse osmosis leachate treatment system.

    PubMed

    Theepharaksapan, S; Chiemchaisri, C; Chiemchaisri, W; Yamamoto, K

    2011-05-01

    Removals of pollutants and toxic organic compounds and reduction in bio-toxicity of leachate along an operating full-scale leachate treatment system utilizing chemical coagulation, sand filtration, microfiltration (MF) and reverse osmosis (RO) membrane were evaluated. High pollutant removals were achieved mainly by coagulation and sand filtration. Major toxic organic pollutants, i.e. DEHP, DBP and bisphenol A were removed by 100%, 99.6% and 98.0%. Acute toxicity test using water flea, Nile Tilapia and common carp and genotoxicity (Comet assay) were conducted to determine toxicity reduction in leachate along the treatment. Ammonia was found to be the main acute toxic compounds in leachate as determined by LC(50) but the effect of organic substances was also observed. DNA damage in fish exposed to diluted raw leachate (10% of LC(50)) was found to be 8.9-24.3% and it was subsequently decreased along the treatment. Correlation between pollutants and its bio-toxicity was established using multivariable analyses.

  3. Lethal coronary air embolism caused by the removal of a double-lumen hemodialysis catheter: a case report.

    PubMed

    Mun, Sung Ha; An, Dong Ai; Choi, Hyun Jung; Kim, Tae Hee; Pin, Jung Woo; Ko, Dong Chan

    2016-06-01

    Coronary air embolism is a rare event. We report a case in which an acute myocardial infarction occurred in the region supplied by the right coronary artery after the removal of a double-lumen hemodialysis catheter. Emergent coronary angiography revealed air bubbles obstructing the mid-segment of the right coronary artery with slow flow phenomenon distally. The patient expired due to myocardial infarction. PMID:27274379

  4. Toxicity in man due to stain removers containing 1,2-dichloropropane.

    PubMed

    Pozzi, C; Marai, P; Ponti, R; Dell'Oro, C; Sala, C; Zedda, S; Locatelli, F

    1985-11-01

    There are reports that 1,2-dichloropropane, a constituent of many commercial solvents and stain removers in Italy, has caused severe liver damage and, sometimes, acute renal failure. Between 1980 and 1983 three cases of 1,2-dichloropropane intoxication (1 by ingestion, 2 by inhalation) were observed. Clinical features included severe liver damage, acute renal failure (2 patients), haemolytic anaemia, and disseminated intravascular coagulation. The most surprising features were haemolytic anaemia and disseminated intravascular coagulation which have not been reported before. The clinical picture was similar despite different modes of exposure. PMID:4063220

  5. Toxicity in man due to stain removers containing 1,2-dichloropropane.

    PubMed Central

    Pozzi, C; Marai, P; Ponti, R; Dell'Oro, C; Sala, C; Zedda, S; Locatelli, F

    1985-01-01

    There are reports that 1,2-dichloropropane, a constituent of many commercial solvents and stain removers in Italy, has caused severe liver damage and, sometimes, acute renal failure. Between 1980 and 1983 three cases of 1,2-dichloropropane intoxication (1 by ingestion, 2 by inhalation) were observed. Clinical features included severe liver damage, acute renal failure (2 patients), haemolytic anaemia, and disseminated intravascular coagulation. The most surprising features were haemolytic anaemia and disseminated intravascular coagulation which have not been reported before. The clinical picture was similar despite different modes of exposure. PMID:4063220

  6. Asthma symptoms in Hispanic children and daily ambient exposures to toxic and criteria air pollutants.

    PubMed Central

    Delfino, Ralph J; Gong, Henry; Linn, William S; Pellizzari, Edo D; Hu, Ye

    2003-01-01

    Although acute adverse effects on asthma have been frequently found for the U.S. Environmental Protection Agency's principal criteria air pollutants, there is little epidemiologic information on specific hydrocarbons from toxic emission sources. We conducted a panel study of 22 Hispanic children with asthma who were 10-16 years old and living in a Los Angeles community with high traffic density. Subjects filled out symptom diaries daily for up to 3 months (November 1999 through January 2000). Pollutants included ambient hourly values of ozone, nitrogen dioxide, sulfur dioxide, and carbon monoxide and 24-hr values of volatile organic compounds (VOCs), particulate matter with aerodynamic diameter < 10 microm (PM10, and elemental carbon (EC) and organic carbon (OC) PM10 fractions. Asthma symptom severity was regressed on pollutants using generalized estimating equations, and peak expiratory flow (PEF) was regressed on pollutants using mixed models. We found positive associations of symptoms with criteria air pollutants (O3, NO2, SO2, PM10), EC-OC, and VOCs (benzene, ethylbenzene, formaldehyde, acetaldehyde, acetone, 1,3-butadiene, tetrachloroethylene, toluene, m,p-xylene, and o-xylene). Selected adjusted odds ratios for bothersome or more severe asthma symptoms from interquartile range increases in pollutants were, for 1.4 ppb 8-hr NO2, 1.27 [95% confidence interval (CI), 1.05-1.54]; 1.00 ppb benzene, 1.23 (95% CI, 1.02-1.48); 3.16 ppb formaldehyde, 1.37 (95% CI, 1.04-1.80); 37 microg/m3 PM10, 1.45 (95% CI, 1.11-1.90); 2.91 microg/m3 EC, 1.85 (95% CI, 1.11-3.08); and 4.64 microg/m3 OC, 1.88 (95% CI, 1.12-3.17). Two-pollutant models of EC or OC with PM10 showed little change in odds ratios for EC (to 1.83) or OC (to 1.89), but PM10 decreased from 1.45 to 1.0. There were no significant associations with PEF. Findings support the view that air toxins in the pollutant mix from traffic and industrial sources may have adverse effects on asthma in children. PMID:12676630

  7. Mercury and Air Toxic Element Impacts of Coal Combustion By-Product Disposal and Utilizaton

    SciTech Connect

    David Hassett; Loreal Heebink; Debra Pflughoeft-Hassett; Tera Buckley; Erick Zacher; Mei Xin; Mae Sexauer Gustin; Rob Jung

    2007-03-31

    The University of North Dakota Energy & Environmental Research Center (EERC) conducted a multiyear study to evaluate the impact of mercury and other air toxic elements (ATEs) on the management of coal combustion by-products (CCBs). The ATEs evaluated in this project were arsenic, cadmium, chromium, lead, nickel, and selenium. The study included laboratory tasks to develop measurement techniques for mercury and ATE releases, sample characterization, and release experiments. A field task was also performed to measure mercury releases at a field site. Samples of fly ash and flue gas desulfurization (FGD) materials were collected preferentially from full-scale coal-fired power plants operating both without and with mercury control technologies in place. In some cases, samples from pilot- and bench-scale emission control tests were included in the laboratory studies. Several sets of 'paired' baseline and test fly ash and FGD materials collected during full-scale mercury emission control tests were also included in laboratory evaluations. Samples from mercury emission control tests all contained activated carbon (AC) and some also incorporated a sorbent-enhancing agent (EA). Laboratory release experiments focused on measuring releases of mercury under conditions designed to simulate CCB exposure to water, ambient-temperature air, elevated temperatures, and microbes in both wet and dry conditions. Results of laboratory evaluations indicated that: (1) Mercury and sometimes selenium are collected with AC used for mercury emission control and, therefore, present at higher concentrations than samples collected without mercury emission controls present. (2) Mercury is stable on CCBs collected from systems both without and with mercury emission controls present under most conditions tested, with the exception of vapor-phase releases of mercury exposed to elevated temperatures. (3) The presence of carbon either from added AC or from unburned coal can result in mercury being

  8. Synthesis of macroporous silica biomass nanocomposite based on XG/MgSiO₃ for the removal of toxic ions.

    PubMed

    Ma, Wei; Meng, Fanqing; Cheng, Zihong; Xin, Gang; Duan, Shibo

    2015-06-01

    Biomass is known as a low-cost adsorbents and there is a need for the development of synthesis method further increase its efficient applications. In this work, a macroporous nanocomposite biomass was synthesized by natural polymer (Xanthan gum) and silicate. The resulting nanocomposite was characterized with XRD, SEM, TEM, BET and FTIR. The analysis confirmed that the functions silicate groups were successfully introduced and the nanocomposite not only showed a special macroporous structure but also showed a better cation exchange capacity which helps to retain cation ions. What's more, in order to investigate the adsorption capacity of the biomass, adsorption experiments were considered. The experiment results revealed that nanocomposite showed a high-efficiency adsorption capacity to remove toxic ions such as arsenic, chromium, mercury and cadmium. PMID:25862015

  9. Can hydroculture be used to enhance the performance of indoor plants for the removal of air pollutants?

    NASA Astrophysics Data System (ADS)

    Irga, P. J.; Torpy, F. R.; Burchett, M. D.

    2013-10-01

    The indoor plant, Syngonium podophyllum, grown in both conventional potting mix and hydroculture, was investigated for its capacity to reduce two components of indoor air pollution; volatile organic compounds (VOCs) and CO2. It was found that, with a moderate increase in indoor light intensity, this species removed significant amounts of CO2 from test chambers, removing up to 61% ± 2.2 of 1000 ppmv over a 40 min period. It was also found that the hydroculture growth medium facilitated increased CO2 removal over potting mix. The VOC removing potential of hydroculture plants was also demonstrated. Whilst the rate of VOC (benzene) removal was slightly lower for hydroculture-grown plants than those grown in potting mix, both removed 25 ppmv from the test chambers within 7 days. The effect of benzene on the community level physiological profiles of rhizospheric bacteria was also assessed. There was less variability in the carbon substrate utilisation profile of the bacterial community from the rhizosphere of hydroculture plants compared to potting mix, however the species present encompassed at least those involved with VOC removal. Overall, we propose that plants grown in hydroculture can simultaneously deplete CO2 and VOCs, and thus may have potential for improving indoor air quality.

  10. Measurement of Ozone Emission and Particle Removal Rates from Portable Air Purifiers

    ERIC Educational Resources Information Center

    Mang, Stephen A.; Walser, Maggie L.; Nizkorodov, Sergey A.; Laux, John M.

    2009-01-01

    Portable air purifiers are popular consumer items, especially in areas with poor air quality. Unfortunately, most users of these air purifiers have minimal understanding of the factors affecting their efficiency in typical indoor settings. Emission of the air pollutant ozone (O[subscript 3]) by certain air purifiers is of particular concern. In an…

  11. Historical data analyses and scientific knowledge suggest complete removal of the abnormal toxicity test as a quality control test.

    PubMed

    Garbe, Joerg H O; Ausborn, Susanne; Beggs, Claire; Bopst, Martin; Joos, Angelika; Kitashova, Alexandra A; Kovbasenco, Olga; Schiller, Claus-Dieter; Schwinger, Martina; Semenova, Natalia; Smirnova, Lilia; Stodart, Fraser; Visalli, Thomas; Vromans, Lisette

    2014-11-01

    In the early 1900s, the abnormal toxicity test (ATT) was developed as an auxiliary means to ensure safe and consistent antiserum production. Today, the ATT is utilized as a quality control (QC) release test according to pharmacopoeial or other regulatory requirements. The study design has not been changed since around 1940. The evidence of abnormal toxicity testing as a prediction for harmful batches is highly questionable and lacks a scientific rationale. Numerous reviews of historical ATT results have revealed that no reliable conclusions can be drawn from this QC measure. Modern pharmaceutical manufacturers have thorough control of the manufacturing process and comply with good manufacturing practice rules. Contaminants are appropriately controlled by complying with the validated manufacturing processes and strict QC batch release confirming batch-to-batch consistency. Recognizing that product safety, efficacy, and stability can be ensured with strict QC measures, nowadays most regulatory authorities do not require the ATT for most product classes. In line with the replacement, reduction, and refinement (3Rs) initiative, the test requirement has been deleted from approximately 80 monographs of the European Pharmacopoeia and for the majority of product classes in the United States. For these reasons, it is recommended that the ATT should be consistently omitted world-wide and be removed from pharmacopoeias and other regulatory requirements.

  12. Toxicity removal assessments related to degradation pathways of azo dyes: Toward an optimization of Electro-Fenton treatment.

    PubMed

    Le, Thi Xuan Huong; Nguyen, Thi Van; Yacouba, Zoulkifli Amadou; Zoungrana, Laetitia; Avril, Florent; Petit, Eddy; Mendret, Julie; Bonniol, Valerie; Bechelany, Mikhael; Lacour, Stella; Lesage, Geoffroy; Cretin, Marc

    2016-10-01

    The degradation pathway of Acid Orange 7 (AO7) by Electro-Fenton process using carbon felt cathode was investigated via HPLC-UV and LC-MS, IC, TOC analysis and bioassays (Vibrio Fischeri 81.9% Microtox(®) screening tests). The TOC removal of AO7 reached 96.2% after 8 h treatment with the optimal applied current density at -8.3 mA cm(-2) and 0.2 mM catalyst concentration. The toxicity of treated solution increased rapidly to its highest value at the early stage of electrolysis (several minutes), corresponding to the formation of intermediate poisonous aromatic compounds such as 1,2-naphthaquinone (NAPQ) and 1,4-benzoquinone (BZQ). Then, the subsequent formation of aliphatic short-chain carboxylic acids like acetic acid, formic acid, before the complete mineralization, leaded to a non-toxic solution after 270 min for 500 mL of AO7 (1 mM). Moreover, a quantitative analysis of inorganic ions (i.e. ammonium, nitrate, sulfate) produced during the course of degradation could help to verify molar balance with regard to original nitrogen and sulfur elements. To conclude, a clear degradation pathway of AO7 was proposed, and could further be applied to other persistent pharmaceuticals in aquatic environment. PMID:27441990

  13. Graphene oxide supported copper oxide nanoneedles: An efficient hybrid material for removal of toxic azo dyes

    NASA Astrophysics Data System (ADS)

    Rajesh, Rajendiran; Iyer, Sahithya S.; Ezhilan, Jayabal; Kumar, S. Senthil; Venkatesan, Rengarajan

    2016-09-01

    Herein, we report a simple, one step synthesis of hybrid copper oxide nanoneedles on graphene oxide sheets (GO-CuONNs) through sonochemical method. The present method affords a facile mean for controlling effective concentration of the active CuO nanoneedles on the graphene oxide sheets, and also offers the necessary stability to the resulting GO-CuONNs structure for adsorption transformations.Furthermore, this hybrid GO-CuONNs is successfully employed in the removal of a series of hazardous ionic organic dyes namely coomassie brilliant blue, methylene blue, congo red and amidoblack 10B. Through careful investigation of the material, we found that the synergetic effect between CuONNs and GO play a significant role in the adsorption of all the dyes studied. The prepared hybrid material contains both hydrophobic and hydrophilic environment which is expected to enhance the electrostatic interaction between the adsorbent and the dye molecules, consequently favouring the adsorption process.

  14. Graphene oxide supported copper oxide nanoneedles: An efficient hybrid material for removal of toxic azo dyes.

    PubMed

    Rajesh, Rajendiran; Iyer, Sahithya S; Ezhilan, Jayabal; Kumar, S Senthil; Venkatesan, Rengarajan

    2016-09-01

    Herein, we report a simple, one step synthesis of hybrid copper oxide nanoneedles on graphene oxide sheets (GO-CuONNs) through sonochemical method. The present method affords a facile mean for controlling effective concentration of the active CuO nanoneedles on the graphene oxide sheets, and also offers the necessary stability to the resulting GO-CuONNs structure for adsorption transformations.Furthermore, this hybrid GO-CuONNs is successfully employed in the removal of a series of hazardous ionic organic dyes namely coomassie brilliant blue, methylene blue, congo red and amidoblack 10B. Through careful investigation of the material, we found that the synergetic effect between CuONNs and GO play a significant role in the adsorption of all the dyes studied. The prepared hybrid material contains both hydrophobic and hydrophilic environment which is expected to enhance the electrostatic interaction between the adsorbent and the dye molecules, consequently favouring the adsorption process.

  15. AUTOMOTIVE DIESEL MAINTENANCE 1. UNIT XIV, I--MAINTAINING THE AIR SYSTEM, CUMMINS DIESEL ENGINE, II--UNIT REMOVAL--TRANSMISSION.

    ERIC Educational Resources Information Center

    Human Engineering Inst., Cleveland, OH.

    THIS MODULE OF A 30-MODULE COURSE IS DESIGNED TO DEVELOP AN UNDERSTANDING OF THE OPERATING PRINCIPLES AND MAINTENANCE OF THE DIESEL ENGINE AIR SYSTEM AND THE PROCEDURES FOR TRANSMISSION REMOVAL. TOPICS ARE (1) DEFINITION OF TERMS RELATED TO THE DIESEL AIR SYSTEM, (2) PRNCIPLES OF DIESEL AIR COMPRESSORS, (3) PRINCIPLES OF AIR STARTING MOTORS, (4)…

  16. The Cus efflux system removes toxic ions via a methionine shuttle.

    PubMed

    Su, Chih-Chia; Long, Feng; Yu, Edward W

    2011-01-01

    Gram-negative bacteria, such as Escherichia coli, frequently utilize tripartite efflux complexes in the resistance-nodulation-cell division (RND) family to expel diverse toxic compounds from the cell. These efflux systems span the entire cell envelope to mediate the phenomenon of bacterial multidrug resistance. The three parts of the efflux complexes are: (1) a membrane fusion protein (MFP) connecting (2) a substrate-binding inner membrane transporter to (3) an outer membrane-anchored channel in the periplasmic space. One such efflux system CusCBA is responsible for extruding biocidal Cu(I) and Ag(I) ions. We recently determined the crystal structures of both the inner membrane transporter CusA and MFP CusB of the CusCBA tripartite efflux system from E. coli. These are the first structures of the heavy-metal efflux (HME) subfamily of the RND efflux pumps. Here, we summarize the structural information of these two efflux proteins and present the accumulated evidence that this efflux system utilizes methionine residues to bind and export Cu(I)/Ag(I). Genetic and structural analyses suggest that the CusA pump is capable of picking up the metal ions from both the periplasm and cytoplasm. We propose a stepwise shuttle mechanism for this pump to extrude metal ions from the cell.

  17. Three-electrode plasma reactor for the removal of toxic gases

    NASA Astrophysics Data System (ADS)

    Gallego, J. L.; Giuliani, L.; Grondona, D.; Minotti, F.

    2015-03-01

    Electrical and spectroscopic measurement for the characterization of a novel three- electrode plasma reactor for the treatment of toxic gases is presented. The three-electrode discharge consists in a dielectric barrier discharge (DBD) combined with a corona discharge (CD). The DBD is generated by applying an alternating high voltage signal between two circular aluminium plate electrodes attached to opposite sides of a disk made of dielectric material. The CD is generated applying a continuous negative high voltage to an external cylindrical mesh electrode, coaxial with the DBD electrode system. The gap between the edge of the DBD system and the mesh electrode is approximately 20 mm wide. Up to five DBD electrode systems can be connected in parallel inside the reactor, axially separated from each other by 30 mm. The electrical characterization consisted in the measurement of the current between the DBD system and the external mesh, and the voltages of the electrodes. In order to understand the dynamics of the streamers, a theoretical determination of the laplacian electric field generated by the biased electrodes was done. Optical emission spectroscopy was performed in the range of wavelengths 280-480 nm, containing the typical spectral bands 2nd positive and 1st negative systems of molecular nitrogen.

  18. Evaluation of pH, alkalinity and temperature during air stripping process for ammonia removal from landfill leachate.

    PubMed

    Campos, Juacyara Carbonelli; Moura, Denise; Costa, Ana Paula; Yokoyama, Lidia; Araujo, Fabiana Valeria da Fonseca; Cammarota, Magali Christe; Cardillo, Luigi

    2013-01-01

    The objective of this research was to evaluate the air stripping technology for the removal of ammonia from landfill leachates. In this process, pH, temperature, airflow rate and operation time were investigated. Furthermore, the relationship between the leachate alkalinity and the ammonia removal efficiency during the process was studied. The leachate used in the tests was generated in the Gramacho Municipal Solid Waste Landfill (Rio de Janeiro State, Brazil). The best results were obtained with a temperature of 60(o)C, and they were independent of the pH value for 7 h of operation (the ammonia nitrogen removal was greater than 95%). A strong influence of the leachate alkalinity on the ammonia nitrogen removal was observed; as the alkalinity decreased, the ammonia concentration also decreased because of prior CO2 removal, which increased the pH and consequently favored the NH3 stripping. The air flow rate, in the values evaluated (73, 96 and 120 L air.h(-1).L(-1) of leachate), did not influence the results.

  19. Application of carbon foam for heavy metal removal from industrial plating wastewater and toxicity evaluation of the adsorbent.

    PubMed

    Lee, Chang-Gu; Song, Mi-Kyung; Ryu, Jae-Chun; Park, Chanhyuk; Choi, Jae-Woo; Lee, Sang-Hyup

    2016-06-01

    Electroplating wastewater contains various types of toxic substances, such as heavy metals, solvents, and cleaning agents. Carbon foam was used as an adsorbent for the removal of heavy metals from real industrial plating wastewater. Its sorption capacity was compared with those of a commercial ion-exchange resin (BC258) and a heavy metal adsorbent (CupriSorb™) in a batch system. The experimental carbon foam has a considerably higher sorption capacity for Cr and Cu than commercial adsorbents for acid/alkali wastewater and cyanide wastewater. Additionally, cytotoxicity test showed that the newly developed adsorbent has low cytotoxic effects on three kinds of human cells. In a pilot plant, the carbon foam had higher sorption capacity for Cr (73.64 g kg(-1)) than for Cu (14.86 g kg(-1)) and Ni (7.74 g kg(-1)) during 350 h of operation time. Oxidation pretreatments using UV/hydrogen peroxide enhance heavy metal removal from plating wastewater containing cyanide compounds.

  20. Evaluation of removal efficiency for acute toxicity and genotoxicity on zebrafish in anoxic-oxic process from selected municipal wastewater treatment plants.

    PubMed

    Zhang, Jing; Zhang, Yaobin; Liu, Wei; Quan, Xie; Chen, Shuo; Zhao, Huimin; Jin, Yihe; Zhang, Wenjuan

    2013-03-01

    The anoxic-oxic (A/O) process has been extensively applied for simultaneous removal of organic contaminants and nitrogen in wastewater treatment. However, very little is known about its ability to remove toxic materials. Municipal wastewater contains various kinds of pollutants, some of which have recalcitrant genotoxicity and may cause potential threat to environment, and even can lead to extinction of many species. In this study, we have selected three municipal wastewater treatment plants (WWTPs) employing anoxic-oxic (A/O) process to evaluate their ability to remove acute toxicity and genotoxicity of wastewater. Mortality rate of zebrafish (Danio rerio) was used to evaluate acute toxicity, while micronucleus (MN) and comet assays were used to detect genotoxicity. Results showed that in this process the acute toxicity was completely removed as the treatment proceeded along with decrease in chemical oxygen demand (COD) (<50 mgL(-1)) in the effluent. However, in these treatment processes the genotoxicity was not significantly reduced, but an increase in genotoxicity was observed. Both MN and comet assays showed similar results. The eliminated effluent may pose genotoxic threaten although its COD level has met the Chinese Sewage Discharge Standard. This study suggests that further treatment of the wastewater is required after the A/O process to remove the genotoxicity and minimize the ecotoxicological risk. PMID:23260253

  1. Toxicity removal efficiency of decentralised sequencing batch reactor and ultra-filtration membrane bioreactors.

    PubMed

    Libralato, Giovanni; Volpi Ghirardini, Annamaria; Avezzù, Francesco

    2010-08-01

    As a consequence of the Water Framework Directive and Marine Strategy Framework Directive, there is now more focus on discharges from wastewater treatment plants both to transitional and marine-coastal waters. The constraint to encourage sustainable water policy to prevent water deterioration and reduce or stop discharges has entailed new requirements for existing wastewater treatment plants in the form of advanced wastewater treatment technologies as further suggested by the Integrated Pollution and Prevention Control Bureau. A whole toolbox of physico-chemical and ecotoxicological parameters to investigate commercial and mixed domestic and industrial discharges was considered to check the efficiency of an Activated-Sludge Sequencing Batch Reactor (AS-SBR) and two Ultra-Filtration Membrane Biological Reactors (UF-MBRs) on a small scale decentralised basis. All discharges were conveyed into Venice lagoon (Italy), one of the widest impacted Mediterranean transitional environment. The UF-MBRs were able to provide good quality effluents potentially suitable for non-potable reuse, as well as reducing specific inorganic micro-pollutants concentration (e.g. metals). Conversely, the AS-SBR showed unpredictable and discontinuous removal abilities. PMID:20619431

  2. Removal of toxic mercury from petroleum oil by newly synthesized molecularly-imprinted polymer.

    PubMed

    Khairi, Nor Ain Shahera; Yusof, Nor Azah; Abdullah, Abdul Halim; Mohammad, Faruq

    2015-05-08

    In recent years, molecularly-imprinted polymers (MIPs) have attracted the attention of several researchers due to their capability for molecular recognition, easiness of preparation, stability and cost-effective production. By taking advantage of these facts, Hg(II) imprinted and non-imprinted copolymers were prepared by polymerizing mercury nitrate stock solution (or without it) with methacrylic acid (MAA), 2-hydroxyl ethyl methacrylate (HEMA), methanol and ethylene glycol dimethacrylate (EGDMA) as the monomer, co-monomer solvent (porogen) and cross-linker, respectively. Thus, the formed Hg(II) imprinted polymer was characterized by using Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), Brunauer, Emmett and Teller (BET) and thermal gravimetric analysis (TGA). The separation and preconcentration characteristics of Hg(II) imprinted polymer were investigated by solid phase extraction (SPE) procedures, and an optimal pH of 7 was investigated as ideal. The specific surface area of the Hg(II) imprinted polymer was found to be 19.45 m2/g with a size range from 100 to 140 µm in diameter. The maximum adsorption capacity was observed to be 1.11 mg/g of Hg(II) imprinted beads with 87.54% removal of Hg(II) ions within the first 5 min. The results of the study therefore confirm that the Hg(II) imprinted polymer can be used multiple times without significantly losing its adsorption capacity.

  3. Removal of Toxic Mercury from Petroleum Oil by Newly Synthesized Molecularly-Imprinted Polymer

    PubMed Central

    Khairi, Nor Ain Shahera; Yusof, Nor Azah; Abdullah, Abdul Halim; Mohammad, Faruq

    2015-01-01

    In recent years, molecularly-imprinted polymers (MIPs) have attracted the attention of several researchers due to their capability for molecular recognition, easiness of preparation, stability and cost-effective production. By taking advantage of these facts, Hg(II) imprinted and non-imprinted copolymers were prepared by polymerizing mercury nitrate stock solution (or without it) with methacrylic acid (MAA), 2-hydroxyl ethyl methacrylate (HEMA), methanol and ethylene glycol dimethacrylate (EGDMA) as the monomer, co-monomer solvent (porogen) and cross-linker, respectively. Thus, the formed Hg(II) imprinted polymer was characterized by using Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), Brunauer, Emmett and Teller (BET) and thermal gravimetric analysis (TGA). The separation and preconcentration characteristics of Hg(II) imprinted polymer were investigated by solid phase extraction (SPE) procedures, and an optimal pH of 7 was investigated as ideal. The specific surface area of the Hg(II) imprinted polymer was found to be 19.45 m2/g with a size range from 100 to 140 µm in diameter. The maximum adsorption capacity was observed to be 1.11 mg/g of Hg(II) imprinted beads with 87.54% removal of Hg(II) ions within the first 5 min. The results of the study therefore confirm that the Hg(II) imprinted polymer can be used multiple times without significantly losing its adsorption capacity. PMID:26006226

  4. Removal and recovery of radionuclides and toxic metals from wastes, soils and materials

    SciTech Connect

    Francis, A.J.

    1993-07-01

    A process has been developed at Brookhaven National Laboratory (BNL) for the removal of metals and radionuclides from contaminated materials, soils, and waste sites (Figure 1). In this process, citric acid, a naturally occurring organic complexing agent, is used to extract metals such as Ba, Cd, Cr, Ni, Zn, and radionuclides Co, Sr, Th, and U from solid wastes by formation of water soluble, metal-citrate complexes. Citric acid forms different types of complexes with the transition metals and actinides, and may involve formation of a bidentate, tridentate, binuclear, or polynuclear complex species. The extract containing radionuclide/metal complex is then subjected to microbiological degradation followed by photochemical degradation under aerobic conditions. Several metal citrate complexes are biodegraded and the metals are recovered in a concentrated form with the bacterial biomass. Uranium forms binuclear complex with citric acid and is not biodegraded. The supernatant containing uranium citrate complex is separated and upon exposure to light, undergoes rapid degradation resulting in the formation of an insoluble, stable polymeric form of uranium. Uranium is recovered as a precipitate (uranium trioxide) in a concentrated form for recycling or for appropriate disposal. This treatment process, unlike others which use caustic reagents, does not create additional hazardous wastes for disposal and causes little damage to soil which can then be returned to normal use.

  5. Removal of Gross Air Embolization from Cardiopulmonary Bypass Circuits with Integrated Arterial Line Filters: A Comparison of Circuit Designs.

    PubMed

    Reagor, James A; Holt, David W

    2016-03-01

    Advances in technology, the desire to minimize blood product transfusions, and concerns relating to inflammatory mediators have lead many practitioners and manufacturers to minimize cardiopulmonary bypass (CBP) circuit designs. The oxygenator and arterial line filter (ALF) have been integrated into one device as a method of attaining a reduction in prime volume and surface area. The instructions for use of a currently available oxygenator with integrated ALF recommends incorporating a recirculation line distal to the oxygenator. However, according to an unscientific survey, 70% of respondents utilize CPB circuits incorporating integrated ALFs without a path of recirculation distal to the oxygenator outlet. Considering this circuit design, the ability to quickly remove a gross air bolus in the blood path distal to the oxygenator may be compromised. This in vitro study was designed to determine if the time required to remove a gross air bolus from a CPB circuit without a path of recirculation distal to the oxygenator will be significantly longer than that of a circuit with a path of recirculation distal to the oxygenator. A significant difference was found in the mean time required to remove a gross air bolus between the circuit designs (p = .0003). Additionally, There was found to be a statistically significant difference in the mean time required to remove a gross air bolus between Trial 1 and Trials 4 (p = .015) and 5 (p =.014) irrespective of the circuit design. Under the parameters of this study, a recirculation line distal to an oxygenator with an integrated ALF significantly decreases the time it takes to remove an air bolus from the CPB circuit and may be safer for clinical use than the same circuit without a recirculation line. PMID:27134304

  6. Removal of Gross Air Embolization from Cardiopulmonary Bypass Circuits with Integrated Arterial Line Filters: A Comparison of Circuit Designs.

    PubMed

    Reagor, James A; Holt, David W

    2016-03-01

    Advances in technology, the desire to minimize blood product transfusions, and concerns relating to inflammatory mediators have lead many practitioners and manufacturers to minimize cardiopulmonary bypass (CBP) circuit designs. The oxygenator and arterial line filter (ALF) have been integrated into one device as a method of attaining a reduction in prime volume and surface area. The instructions for use of a currently available oxygenator with integrated ALF recommends incorporating a recirculation line distal to the oxygenator. However, according to an unscientific survey, 70% of respondents utilize CPB circuits incorporating integrated ALFs without a path of recirculation distal to the oxygenator outlet. Considering this circuit design, the ability to quickly remove a gross air bolus in the blood path distal to the oxygenator may be compromised. This in vitro study was designed to determine if the time required to remove a gross air bolus from a CPB circuit without a path of recirculation distal to the oxygenator will be significantly longer than that of a circuit with a path of recirculation distal to the oxygenator. A significant difference was found in the mean time required to remove a gross air bolus between the circuit designs (p = .0003). Additionally, There was found to be a statistically significant difference in the mean time required to remove a gross air bolus between Trial 1 and Trials 4 (p = .015) and 5 (p =.014) irrespective of the circuit design. Under the parameters of this study, a recirculation line distal to an oxygenator with an integrated ALF significantly decreases the time it takes to remove an air bolus from the CPB circuit and may be safer for clinical use than the same circuit without a recirculation line.

  7. Removal of Gross Air Embolization from Cardiopulmonary Bypass Circuits with Integrated Arterial Line Filters: A Comparison of Circuit Designs

    PubMed Central

    Reagor, James A.; Holt, David W.

    2016-01-01

    Abstract: Advances in technology, the desire to minimize blood product transfusions, and concerns relating to inflammatory mediators have lead many practitioners and manufacturers to minimize cardiopulmonary bypass (CBP) circuit designs. The oxygenator and arterial line filter (ALF) have been integrated into one device as a method of attaining a reduction in prime volume and surface area. The instructions for use of a currently available oxygenator with integrated ALF recommends incorporating a recirculation line distal to the oxygenator. However, according to an unscientific survey, 70% of respondents utilize CPB circuits incorporating integrated ALFs without a path of recirculation distal to the oxygenator outlet. Considering this circuit design, the ability to quickly remove a gross air bolus in the blood path distal to the oxygenator may be compromised. This in vitro study was designed to determine if the time required to remove a gross air bolus from a CPB circuit without a path of recirculation distal to the oxygenator will be significantly longer than that of a circuit with a path of recirculation distal to the oxygenator. A significant difference was found in the mean time required to remove a gross air bolus between the circuit designs (p = .0003). Additionally, There was found to be a statistically significant difference in the mean time required to remove a gross air bolus between Trial 1 and Trials 4 (p = .015) and 5 (p =.014) irrespective of the circuit design. Under the parameters of this study, a recirculation line distal to an oxygenator with an integrated ALF significantly decreases the time it takes to remove an air bolus from the CPB circuit and may be safer for clinical use than the same circuit without a recirculation line. PMID:27134304

  8. The current practice of health risk assessment: Potential impact on standards for toxic air contaminants

    SciTech Connect

    Paustenbach, D.J.; Jernigan, J.D.; Finley, B.L.; Ripple, S.R.; Keenan, R.E. )

    1990-12-01

    Since the Bhopal incident, the public has placed pressure on regulatory agencies to set community exposure limits for the dozens of chemicals that may be released by manufacturing facilities. More or less objective limits can be established for the vast majority of these chemicals through the use of risk assessment. However, each step of the risk assessment process (i.e., hazard identification, dose-response assessment, exposure assessment, and risk characterization) contains a number of pitfalls that scientists need to avoid to ensure that valid limits are established. For example, in the hazard identification step there has been little discrimination among animal carcinogens with respect to mechanism of action or the epidemiology experience. In the dose-response portion, rarely is the range of plausible estimated risks presented. Physiologically based pharmacokinetic (PB-PK) models should be used to understand the difference between the tissue doses and the administered dose, as well as the difference in target tissue concentrations of the toxicant between rodents and humans. Biologically-based models like the Moolgavkar-Knudson-Venzon (MKV) should be developed and used, when appropriate. The exposure assessment step can be significantly improved by using more sensitive and specific sampling and analytical methods, more accurate exposure parameters, and computer models that can account for complex environmental factors. Whenever possible, model predictions of exposure and uptake should be validated by biological monitoring of exposed persons (urine, blood, adipose) or by field measurements of plants, soil, fish, air, or water. In each portion of an assessment, the weight of evidence approach should be used to identify the most defensible value. 129 refs.

  9. Removal of 2,4-dichlorophenol from aqueous solution by static-air-activated carbon fibers.

    PubMed

    Wang, Jian-Ping; Chen, Yong-Zhen; Feng, Hui-Min; Zhang, Shu-Juan; Yu, Han-Qing

    2007-09-01

    Static-air-activated carbon fibers (ACFs) with lotus-root-like axially porous structure were used to adsorb 2,4-dichlorophenol (2,4-DCP) from aqueous solution. The adsorption isotherm was evaluated in the pH range 3.0-11.0. Results indicated that both Langmuir and Redlich-Peterson adsorption isotherms were appropriate for describing the adsorption characteristics of 2,4-DCP at various pH values and that lower pH values were favorable for adsorption. The adsorption of 2,4-DCP was controlled by the synergetic effects of pi-pi interaction and electrostatic attraction, and the former was dominant. Breakthrough curve results showed that the 2,4-DCP removal efficiency increased with an increase in the empty-bed contact time (EBCT). An EBCT of 0.660 min was sufficient for the adsorption of 2,4-DCP onto ACF, indicating a high adsorption rate. Desorption experiment results revealed that the ACF saturated with 2,4-DCP could be regenerated effectively by a 0.001 M NaOH solution. PMID:17509602

  10. Removal of low-concentration BTX in air using a combined plasma catalysis system.

    PubMed

    Fan, X; Zhu, T L; Wang, M Y; Li, X M

    2009-06-01

    The behavior of non-thermal plasma (NTP) and combined plasma catalysis (CPC) was investigated for removal of low-concentration benzene, toluene and p-xylene (BTX mixture) in air using a link tooth wheel-cylinder plasma reactor. Combining NTP with MnO(x)/Al(2)O(3) catalyst after the discharge zone (CPC) significantly promoted BTX conversion and improved the energy efficiency. For a specific input energy (SIE) of 10 JL(-1), the conversion of benzene, toluene and p-xylene reached 94%, 97% and 95%, respectively. The introduction of MnO(x)/Al(2)O(3) catalyst also moved the BTX conversion towards total oxidation and reduced the emission of O(3) and NO(2) as compared to NTP alone. For an SIE of 10 JL(-1), the O(3) outlet concentration decreased from 46.7 for NTP alone to 1.9 ppm for CPC, while the NO(2) emission correspondingly decreased from 1380 to 40 ppb.

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

    SciTech Connect

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

    1997-12-01

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

  12. Separate and Unequal: Residential Segregation and Estimated Cancer Risks Associated with Ambient Air Toxics in U.S. Metropolitan Areas

    PubMed Central

    Morello-Frosch, Rachel; Jesdale, Bill M.

    2006-01-01

    This study examines links between racial residential segregation and estimated ambient air toxics exposures and their associated cancer risks using modeled concentration estimates from the U.S. Environmental Protection Agency’s National Air Toxics Assessment. We combined pollutant concentration estimates with potencies to calculate cancer risks by census tract for 309 metropolitan areas in the United States. This information was combined with socioeconomic status (SES) measures from the 1990 Census. Estimated cancer risks associated with ambient air toxics were highest in tracts located in metropolitan areas that were highly segregated. Disparities between racial/ethnic groups were also wider in more segregated metropolitan areas. Multivariate modeling showed that, after controlling for tract-level SES measures, increasing segregation amplified the cancer risks associated with ambient air toxics for all racial groups combined [highly segregated areas: relative cancer risk (RCR) = 1.04; 95% confidence interval (CI), 1.01–107; extremely segregated areas: RCR = 1.32; 95% CI, 1.28–1.36]. This segregation effect was strongest for Hispanics (highly segregated areas: RCR = 1.09; 95% CI, 1.01–1.17; extremely segregated areas: RCR = 1.74; 95% CI, 1.61–1.88) and weaker among whites (highly segregated areas: RCR = 1.04; 95% CI, 1.01–1.08; extremely segregated areas: RCR = 1.28; 95% CI, 1.24–1.33), African Americans (highly segregated areas: RCR = 1.09; 95% CI, 0.98–1.21; extremely segregated areas: RCR = 1.38; 95% CI, 1.24–1.53), and Asians (highly segregated areas: RCR = 1.10; 95% CI, 0.97–1.24; extremely segregated areas: RCR = 1.32; 95% CI, 1.16–1.51). Results suggest that disparities associated with ambient air toxics are affected by segregation and that these exposures may have health significance for populations across racial lines. PMID:16507462

  13. Performance evaluation of oxygen, air and nitrate for the microaerobic removal of hydrogen sulphide in biogas from sludge digestion.

    PubMed

    Díaz, I; Lopes, A C; Pérez, S I; Fdz-Polanco, M

    2010-10-01

    The removal performance of hydrogen sulphide in severely polluted biogas produced during the anaerobic digestion of sludge was studied by employing pure oxygen, air and nitrate as oxidant reactives supplied to the biodigester. Research was performed in a 200-L digester with an hydraulic retention time (HRT) of ∼20 days under mesophilic conditions. The oxygen supply (0.25 N m³/m³ feed) to the bioreactor successfully reduced the hydrogen sulphide content from 15,811 mg/N m³ to less than 400 mg/N m³. The introduction of air (1.27 N m³/m³ feed) removed more than 99% of the hydrogen sulphide content, with a final concentration of ∼55 mg/N m³. COD removal, VS reduction and methane yield were not affected under microaerobic conditions; however, methane concentration in the biogas decreased when air was employed as a result of nitrogen dilution. The nitrate addition was not effective for hydrogen sulphide removal in the biogas.

  14. Operation of a breadboard liquid-sorbent/membrane-contactor system for removing carbon dioxide and water vapor from air

    NASA Technical Reports Server (NTRS)

    Mccray, Scott B.; Ray, Rod; Newbold, David D.; Millard, Douglas L.; Friesen, Dwayne T.; Foerg, Sandra

    1992-01-01

    Processes to remove and recover carbon dioxide (CO2) and water vapor from air are essential for successful long-duration space missions. This paper presents results of a developmental program focused on the use of a liquid-sorbent/membrane-contactor (LSMC) system for removal of CO2 and water vapor from air. In this system, air from the spacecraft cabin atmosphere is circulated through one side of a hollow-fiber membrane contactor. On the other side of the membrane contactor is flowed a liquid sorbent, which absorbs the CO2 and water vapor from the feed air. The liquid sorbent is then heated to desorb the CO2 and water vapor. The CO2 is subsequently removed from the system as a concentrated gas stream, whereas the water vapor is condensed, producing a water stream. A breadboard system based on this technology was designed and constructed. Tests showed that the LSMC breadboard system can produce a CO2 stream and a liquid-water stream. Details are presented on the operation of the system, as well as the effects on performance of variations in feed conditions.

  15. Evaluation of effectiveness of EDTA and sodium thiosulfate in removing metal toxicity toward sea urchin embryo-larval applying the TIE.

    PubMed

    Resgalla, C; Poleza, F; Souza, R C; Máximo, M V; Radetski, C M

    2012-09-01

    Since the development of the TIE (Toxicity Identification and Evaluation) in 1988 it has been assumed that the capacity of EDTA and sodium thiosulfate to complex some metals, and thus remove their toxicity, can be applied to both freshwater and seawater ecotoxicological tests and the results subsequently interpreted. However, it is now known that there is a wide variability in the extent of this complexation. In this context, the removal of toxicity caused by the presence of Hg(2+), Cd(2+), Cu(2+), Cr(6+), Zn(2+), Ni(2+), Pb(2+), Ag(1+) and Se(2+), through metal complexation by EDTA and sodium thiosulfate, in relation to the performance of embryo-larval tests with the sea urchin Arbacia lixula was investigated. It was observed that EDTA was capable of removing the toxicity of Pb(2+), Zn(2+) and Cu(2+) while sodium thiosulfate only reduced the toxicity of Ag(1+). Compared to the complexation observed in freshwater ecotoxicological tests, the complexing agents used in this study (EDTA and sodium thiosulfate) have a lower capacity to complex metals in the marine ecotoxicological test with A. lixula.

  16. The pathway of in-situ ammonium removal from aerated municipal solid waste bioreactor: nitrification/denitrification or air stripping?

    PubMed

    Hao, Yong-Jun; Ji, Min; Chen, Ying-Xu; Wu, Wei-Xiang; Hao, Yong-Jun; Zhang, Shu-Guang; Liu, Han-Qiao

    2010-12-01

    In-situ ammonium removal from municipal solid waste (MSW) landfill is an attractive method due to its economic advantages. In this study, two simulated MSW bioreactors with different degrees of initial bio-stabilization were utilized to investigate the effects of intermittent aeration mode and the addition of activated sludge on the removal of ammonium. The results showed that up to 90% of ammonium could be removed and the amount of NO(x)-N produced was less than 1% of NH4 (+)-N removed in both reactors. The pH values increased rapidly and finally arrived at a high level of 8.5-8.8. The efficiency of ammonium removal was improved by increasing the continuous aeration time, but it was not affected by the addition of activated sludge. A portion of liquid escaped from the reactors in the form of vapour, and as high as 195-258 mg L(-1) of NH(4) ( +)-N was detected in the vapour collector. According to calculation, nitrification was inhibited by the high level of free ammonia in the bioreactors. As a result, air stripping was enhanced and became the primary pathway of ammonium removal. Therefore, controlling free ammonia concentration was essential in ammonium removal from the aerated MSW bioreactor.

  17. Ultra High Efficiency ESP for Fine Particulate and Air Toxics Control

    SciTech Connect

    Srinivasachar, Srivats; Pease, Benjamin R.; Porle, Kjell; Mauritzson, Christer; Haythornthwaite, Sheila

    1997-07-01

    Nearly ninety percent of U.S. coal-fired utility boilers are equipped with electrostatic precipitators (ESP). Cost effective retrofittable ESP technologies are the only means to accomplish Department of Energy's (DOE) goal of a major reduction in fine particulate and air toxic emissions from coal-fired power plants. Particles in the size range of 0.1 to 5 {micro}m typically escape ESPs. Metals, such as arsenic, cadmium, lead, molybdenum and antimony, concentrate on these particles. This is the main driver for improved fine particulate control. Vapor phase emissions of mercury, selenium and arsenic are also of major concern. Current dry ESPs, which operate at temperatures greater than 280 F, provide little control for vapor phase toxics. The need for inherent improvement to ESPs has to be considered keeping in perspective the current trend towards the use of low sulfur coals. Switching to low sulfur coals is the dominant approach for SO{sub 2} emission reduction in the utility industry. Low sulfur coals generate high resistivity ash, which can cause an undesirable phenomenon called ''back corona.'' Higher particulate emissions occur if there is back corona in the ESP. Results of the pilot-scale testing identified the ''low temperature ESP'' concept to have the biggest impact for the two low sulfur coals investigated. Lowering the flue gas temperature to 220 F provided the maximum impact in terms of decreased emissions. Intermediate operating temperatures (reduction from 340 to 270 F) also gave significant ESP performance improvement. A significant reduction in particulate emissions was also noted when the flue gas humidity was increased (temperature held constant) from the baseline condition for these moderately high resistivity ash coals. Independent control of flue gas humidity and temperature was an important and a notable element in this project. Mercury emissions were also measured as a function of flue gas temperature. Mercury emissions decreased as the flue

  18. Identifying inequitable exposure to toxic air pollution in racialized and low-income neighbourhoods to support pollution prevention.

    PubMed

    Kershaw, Suzanne; Gower, Stephanie; Rinner, Claus; Campbell, Monica

    2013-05-01

    Numerous environmental justice studies have confirmed a relationship between population characteristics such as low-income or minority status and the location of environmental health hazards. However, studies of the health risks from exposure to harmful substances often do not consider their toxicological characteristics. We used two different methods, the unit-hazard and the distance-based approach, to evaluate demographic and socio-economic characteristics of the population residing near industrial facilities in the City of Toronto, Canada. In addition to the mass of air emissions obtained from the national pollutant release inventory (NPRI), we also considered their toxicity using toxic equivalency potential (TEP) scores. Results from the unit-hazard approach indicate no significant difference in the proportion of low-income individuals living in host versus non-host census tracts (t(107) = 0.3, P = 0.735). However, using the distance-based approach, the proportion of low-income individuals was significantly higher (+5.1%, t(522) = 6.0, P <0.001) in host tracts, while the indicator for "racialized" communities ("visible minority") was 16.1% greater (t(521) = 7.2, P <0.001) within 2 km of a NPRI facility. When the most toxic facilities by non-carcinogenic TEP score were selected, the rate of visible minorities living near the most toxic NPRI facilities was significantly higher (+12.9%, t(352) = 3.5, P = 0.001) than near all other NPRI facilities. TEP scores were also used to identify areas in Toronto that face a double burden of poverty and air toxics exposure in order to prioritise pollution prevention.

  19. Recent advances in the use of graphene-family nanoadsorbents for removal of toxic pollutants from wastewater.

    PubMed

    Chowdhury, Shamik; Balasubramanian, Rajasekhar

    2014-02-01

    Adsorption technology is widely considered as the most promising and robust method of purifying water at low cost and with high-efficiency. Carbon-based materials have been extensively explored for adsorption applications because of their good chemical stability, structural diversity, low density, and suitability for large scale production. Graphene--a single atomic layer of graphite--is the newest member in the family of carbon allotropes and has emerged as the "celeb" material of the 21st century. Since its discovery in 2004 by Novoselov, Geim and co-workers, graphene has attracted increased attention in a wide range of applications due to its unprecedented electrical, mechanical, thermal, optical and transport properties. Graphene's infinitely high surface-to-volume ratio has resulted in a large number of investigations to study its application as a potential adsorbent for water purification. More recently, other graphene related materials such as graphene oxide, reduced graphene oxide, and few-layered graphene oxide sheets, as well as nanocomposites of graphene materials have also emerged as a promising group of adsorbent for the removal of various environmental pollutants from waste effluents. In this review article, we present a synthesis of the current knowledge available on this broad and versatile family of graphene nanomaterials for removal of dyes, potentially toxic elements, phenolic compounds and other organic chemicals from aquatic systems. The challenges involved in the development of these novel nanoadsorbents for decontamination of wastewaters have also been examined to help identify future directions for this emerging field to continue to grow.

  20. Biogeochemical Processes Related to Metal Removal and Toxicity Reduction in the H-02 Constructed Wetland, Savannah River Site

    NASA Astrophysics Data System (ADS)

    Burgess, E. A.; Mills, G. L.; Harmon, M.; Samarkin, V.

    2011-12-01

    The H-02 wetland system was designed to treat building process water and storm water runoff from multiple sources associated with the Tritium Facility at the DOE-Savannah River Site, Aiken, SC. The wetland construction included the addition of gypsum (calcium sulfate) to foster a sulfate-reducing bacterial population. Conceptually, the wetland functions as follows: ? Cu and Zn initially bind to both dissolved and particulate organic detritus within the wetland. ? A portion of this organic matter is subsequently deposited into the surface sediments within the wetland. ? The fraction of Cu and Zn that is discharged in the wetland effluent is organically complexed, less bioavailable, and consequently, less toxic. ? The Cu and Zn deposited in the surface sediments are eventually sequestered into insoluble sulfide minerals in the wetland. Development of the H-02 system has been closely monitored; sampling began in August 2007, shortly after its construction. This monitoring has included the measurement of water quality parameters, Cu and Zn concentrations in surface water and sediments, as well as, characterization of the prokaryotic (e.g., bacterial) component of wetland biogeochemical processes. Since the beginning of the study, the mean influent Cu concentration was 31.5±12.1 ppb and the mean effluent concentration was 11.9±7.3 ppb, corresponding to an average Cu removal of 64%. Zn concentrations were more variable, averaging 39.2±13.8 ppb in the influent and 25.7±21.3 ppb in the effluent. Average Zn removal was 52%. The wetland also ameliorated high pH values associated with influent water to values similar to those measured at reference sites. Seasonal variations in DOC concentration corresponded to seasonal variations in Cu and Zn removal efficiency. The concentration of Cu and Zn in the surface layer of the sediments has increased over the lifetime of the wetland and, like removal efficiency, demonstrated seasonal variation. Within its first year, the H-02

  1. Abiotic and biological mechanisms of nitric oxide removal from waste air in biotrickling filters.

    PubMed

    Chen, Jian-Meng; Ma, Jian-Feng

    2006-01-01

    Nitric oxide (NO) may participate in the ozone layer depletion and forming of nitric acid. Abiotic and biological mechanisms of NO removal from waste gases were studied in a biotrickling filter. The abiotic NO removal rate in the biotrickling filter was estimated by a review of the literature. The abiotic and biological removals were also verified in the biotrickling filter. The result has shown that chemical oxidation and bionitrification were both involved in the NO removal. It was found that the NO removal in high concentration (approximately 1000 ppm or higher) was in large measure the result of abiotic removal in both gas-phase and liquid-phase reactions. When NO concentration is low (less than approximately 100 ppm), bionitrification was the main process in the NO removal process in the biotrickling filter.

  2. Thermal Stress and Toxicity

    EPA Science Inventory

    Elevating ambient temperature above thermoneutrality exacerbates toxicity of most air pollutants, insecticides, and other toxic chemicals. On the other hand, safety and toxicity testing of toxicants and drugs is usually performed in mice and rats maintained at subthermoneutral te...

  3. Application of ultrasound and air stripping for the removal of aromatic hydrocarbons from spent sulfidic caustic for use in autotrophic denitrification as an electron donor.

    PubMed

    Lee, Jae-Ho; Park, Jeung-Jin; Choi, Gi-Choong; Byun, Im-Gyu; Park, Tae-Joo; Lee, Tae-Ho

    2013-01-01

    Spent sulfidic caustic (SSC) produced from petroleum industry can be reused to denitrify nitrate-nitrogen via a biological nitrogen removal process as an electron donor for sulfur-based autotrophic denitrification, because it has a large amount of dissolved sulfur. However, SSC has to be refined because it also contains some aromatic hydrocarbons, typically benzene, toluene, ethylbenzene, xylene (BTEX) and phenol that are recalcitrant organic compounds. In this study, laboratory-scale ultrasound irradiation and air stripping treatment were applied in order to remove these aromatic hydrocarbons. In the ultrasound system, both BTEX and phenol were exponentially removed by ultrasound irradiation during 60 min of reaction time to give the greatest removal efficiency of about 80%. Whereas, about 95% removal efficiency of BTEX was achieved, but not any significant phenol removal, within 30 min in the air stripping system, indicating that air stripping was a more efficient method than ultrasound irradiation. However, since air stripping did not remove any significant phenol, an additional process for degrading phenol was required. Accordingly, we applied a combined ultrasound and air stripping process. In these experiments, the removal efficiencies of BTEX and phenol were improved compared to the application of ultrasound and air stripping alone. Thus, the combined ultrasound and air stripping treatment is appropriate for refining SSC.

  4. USING THE AIR QUALITY MODEL TO ANALYZE THE CONCENTRATIONS OF AIR TOXICS OVER THE CONTINENTAL U.S.

    EPA Science Inventory

    The U.S. Environmental Protection Agency is examining the concentrations and deposition of hazardous air pollutants (HAPs), which include a large number of chemicals, ranging from non reactive (i.e. carbon tetrachloride) to reactive (i.e. formaldehyde), exist in gas, aqueous, and...

  5. Occurrence and Concentrations of Toxic VOCs in the Ambient Air of Gumi, an Electronics-Industrial City in Korea.

    PubMed

    Baek, Sung-Ok; Suvarapu, Lakshmi Narayana; Seo, Young-Kyo

    2015-08-05

    This study was carried out to characterize the occurrence and concentrations of a variety of volatile organic compounds (VOCs) including aliphatic, aromatic, halogenated, nitrogenous, and carbonyl compounds, in the ambient air of Gumi City, where a large number of electronics industries are found. Two field monitoring campaigns were conducted for a one year period in 2003/2004 and 2010/2011 at several sampling sites in the city, representing industrial, residential and commercial areas. More than 80 individual compounds were determined in this study, and important compounds were then identified according to their abundance, ubiquity and toxicity. The monitoring data revealed toluene, trichloroethylene and acetaldehyde to be the most significant air toxics in the city, and their major sources were mainly industrial activities. On the other hand, there was no clear evidence of an industrial impact on the concentrations of benzene and formaldehyde in the ambient air of the city. Overall, seasonal variations were not as distinct as locational variations in the VOCs concentrations, whereas the within-day variations showed a typical pattern of urban air pollution, i.e., increase in the morning, decrease in the afternoon, and an increase again in the evening. Considerable decreases in the concentrations of VOCs from 2003 to 2011 were observed. The reductions in the ambient concentrations were confirmed further by the Korean PRTR data in industrial emissions within the city. Significant decreases in the concentrations of benzene and acetaldehyde were also noted, whereas formaldehyde appeared to be almost constant between the both campaigns. The decreased trends in the ambient levels were attributed not only to the stricter regulations for VOCs in Korea, but also to the voluntary agreement of major companies to reduce the use of organic solvents. In addition, a site planning project for an eco-friendly industrial complex is believed to play a contributory role in improving

  6. Occurrence and Concentrations of Toxic VOCs in the Ambient Air of Gumi, an Electronics-Industrial City in Korea

    PubMed Central

    Baek, Sung-Ok; Suvarapu, Lakshmi Narayana; Seo, Young-Kyo

    2015-01-01

    This study was carried out to characterize the occurrence and concentrations of a variety of volatile organic compounds (VOCs) including aliphatic, aromatic, halogenated, nitrogenous, and carbonyl compounds, in the ambient air of Gumi City, where a large number of electronics industries are found. Two field monitoring campaigns were conducted for a one year period in 2003/2004 and 2010/2011 at several sampling sites in the city, representing industrial, residential and commercial areas. More than 80 individual compounds were determined in this study, and important compounds were then identified according to their abundance, ubiquity and toxicity. The monitoring data revealed toluene, trichloroethylene and acetaldehyde to be the most significant air toxics in the city, and their major sources were mainly industrial activities. On the other hand, there was no clear evidence of an industrial impact on the concentrations of benzene and formaldehyde in the ambient air of the city. Overall, seasonal variations were not as distinct as locational variations in the VOCs concentrations, whereas the within-day variations showed a typical pattern of urban air pollution, i.e., increase in the morning, decrease in the afternoon, and an increase again in the evening. Considerable decreases in the concentrations of VOCs from 2003 to 2011 were observed. The reductions in the ambient concentrations were confirmed further by the Korean PRTR data in industrial emissions within the city. Significant decreases in the concentrations of benzene and acetaldehyde were also noted, whereas formaldehyde appeared to be almost constant between the both campaigns. The decreased trends in the ambient levels were attributed not only to the stricter regulations for VOCs in Korea, but also to the voluntary agreement of major companies to reduce the use of organic solvents. In addition, a site planning project for an eco-friendly industrial complex is believed to play a contributory role in improving

  7. Prenatal exposure to air toxics and risk of Wilms’ tumor in 0-5 year old children

    PubMed Central

    Shrestha, Anshu; Ritz, Beate; Wilhelm, Michelle; Qiu, Jiaheng; Cockburn, Myles; Heck, Julia E

    2014-01-01

    Objective To study prenatal air toxics exposure and Wilms’ tumor in children. Methods We identified 337 Wilms’ tumor cases among children <6 years (1988-2008) from the California Cancer Registry, randomly selected 96,514 controls from California birth rolls in 20:1 ratio matched to all cancer cases, then linked birth addresses to air monitors within 15 miles to assess exposures. Multiple logistic regressions were applied to estimate effects. Results Children prenatally exposed to formaldehyde, polycyclic aromatic hydrocarbons, perchloroethylene, or acetaldehyde in the third trimester had an increased odds of Wilms’ tumor per interquartile increase in concentration (OR [95%CI]: 1.28 [1.12, 1.45], 1.10 [0.99, 1.22], 1.09 [1.00, 1.18], 1.25 [1.07, 1.45] respectively). Conclusions We found positive associations for four air toxics. This is the first study of this kind. Future studies are needed to confirm our findings. PMID:24854250

  8. Air

    MedlinePlus

    ... do to protect yourself from dirty air . Indoor air pollution and outdoor air pollution Air can be polluted indoors and it can ... this chart to see what things cause indoor air pollution and what things cause outdoor air pollution! Indoor ...

  9. Personal exposures, indoor-outdoor relationships, and breath levels of toxic air pollutants measured for 355 persons in New Jersey

    NASA Astrophysics Data System (ADS)

    Wallace, Lance A.; Pellizzari, Edo D.; Hartwell, Ty D.; Sparacino, Charles M.; Sheldon, Linda S.; Zelon, Harvey

    EPA's TEAM Study has measured exposures to 20 volatile organic compounds in personal air, outdoor air, drinking water and the breath of 355 persons in NJ, in the fall of 1981. The NJ residents were selected by a probability sampling scheme to represent 128,000 inhabitants of Elizabeth and Bayonne. Participants carried a personal monitor to collect two 12-h air samples and gave a breath sample at the end of the day. Two consecutive 12-h outdoor air samples were also collected on identical Tenax cartridges in the back yards of 90 of the participants. About 3000 samples were collected, of which 1000 were quality control samples. Eleven compounds were often present in air. Personal exposures were consistently higher than outdoor concentrations for these chemicals, and were sometimes ten times the outdoor concentrations. Indoor sources appeared responsible for much of the difference. Breath concentrations also usually exceed outdoor concentrations, and correlated more strongly with personal exposures than with outdoor concentrations. Some activities (smoking, driving, visiting dry cleaners or service stations) and occupations (chemical, paint and plastics plants) were associated with significantly elevated exposures and breath levels for certain toxic chemicals.

  10. Comparison of Benzene & Toluene removal from synthetic polluted air with use of Nano photocatalyticTiO2/ ZNO process

    PubMed Central

    2014-01-01

    Background Mono aromatic hydrocarbons (BTEX) are a group of hazardous pollutants which originate from sources such as refineries, gas, and oil extraction fields, petrochemicals and paint and glue industries. Conventional methods, including incineration, condensation, adsorption and absorption have been used for removal of VOCs. None of these methods is economical for removal of pollutants of polluted air with low to moderate concentrations. The heterogeneous photocatalytic processes involve the chemical reactions to convert pollutant to carbon dioxide and water. The aim of this paper is a comparison of Benzene & Toluene removal from synthetic polluted air using a Nano photocatalytic TiO2/ ZNO process. Results The X-ray diffraction (XRD) patterns showed that Nano crystals of TiO2 and ZNO were in anatase and rutile phases. Toluene & benzene were decomposed by TiO2/ ZNO Nano photocatalyst and UV radiation. Kruskal-wallis Test demonstrated that there are significant differences (pvalue < 0.05) between pollutant concentrations in different operational conditions. Conclusions Degradation of toluene & benzene increases with increasing UV intensity and decreasing initial concentrations. Effect of TiO2/ZNO Nano photocatalyst on benzene is less than that on toluene. In this research, Toluene & benzene removal by TiO2/ZNO and UV followed first-order reactions. PMID:24499601

  11. Exposure information in environmental health research: Current opportunities and future directions for particulate matter, ozone, and toxic air pollutants

    SciTech Connect

    McKone, Thomas E.; Ryan, P. Barry; Ozkaynak, Haluk

    2007-02-01

    Understanding and quantifying outdoor and indoor sources of human exposure are essential but often not adequately addressed in health-effects studies for air pollution. Air pollution epidemiology, risk assessment, health tracking and accountability assessments are examples of health-effects studies that require but often lack adequate exposure information. Recent advances in exposure modeling along with better information on time-activity and exposure factors data provide us with unique opportunities to improve the assignment of exposures for both future and ongoing studies linking air pollution to health impacts. In September 2006, scientists from the US Environmental Protection Agency (EPA) and the Centers for Disease Control and Prevention (CDC) along with scientists from the academic community and state health departments convened a symposium on air pollution exposure and health in order to identify, evaluate, and improve current approaches for linking air pollution exposures to disease. This manuscript presents the key issues, challenges and recommendations identified by the exposure working group, who used cases studies of particulate matter, ozone, and toxic air pollutant exposure to evaluate health-effects for air pollution. One of the over-arching lessons of this workshop is that obtaining better exposure information for these different health-effects studies requires both goal-setting for what is needed and mapping out the transition pathway from current capabilities to meeting these goals. Meeting our long-term goals requires definition of incremental steps that provide useful information for the interim and move us toward our long-term goals. Another over-arching theme among the three different pollutants and the different health study approaches is the need for integration among alternate exposure assessment approaches. For example, different groups may advocate exposure indicators, biomonitoring, mapping methods (GIS), modeling, environmental media

  12. Cerebral Air Embolism Following the Removal of a Central Venous Catheter in the Absence of Intracardiac Right-to-Left Shunting

    PubMed Central

    Eum, Da Hae; Lee, Seung Hwan; Kim, Hyung Won; Jung, Myung Jae; Lee, Jae Gil

    2015-01-01

    Abstract Air embolism following central venous catheter (CVC) removal is a relatively uncommon complication. Despite its rare occurrence, an air embolism can lead to serious outcomes. One of the most fatal complications is cerebral air embolism. We report a case of cerebral air embolism that occurred after the removal of a CVC in a patient with an underlying idiopathic pulmonary fibrosis, subcutaneous emphysema, pneumomediastinum, and a possible intrapulmonary shunt. Although the patient had a brief period of recovery, his condition deteriorated again, and retention of carbon dioxide was sustained due to aggravation of pneumonia. Despite full coverage of antibiotics and maximum care with the ventilator, the patient died about 5 weeks after the removal of the CVC. We suggest that strict compliance to protocols is required even while removing the catheter. Furthermore, additional caution to avoid air embolism is demanded in high-risk patients, such as in this case. PMID:25837752

  13. Removal of toxic metals from solution by leaf, stem and root phytomass of Quercus ilex L. (holly oak).

    PubMed

    Prasad, M N; Freitas, H

    2000-11-01

    Increased consciousness for safeguarding the aqueous environment has prompted a search for alternative technologies for the removal of toxic metal ions from aqueous solutions. In this regard, a wide variety of biomass is being considered as adsorbents of heavy metals for treatment of industrial and domestic wastewaters as well as natural waters, including drinking water. In the present investigation, the potential of Quercus ilex phytomass from stem, leaf and root as an adsorbent of chromium (Cr), nickel (Ni), copper (Cu), cadmium (Cd) and lead (Pb) at ambient temperature was investigated. The metal uptake capacity of the root for different metals was found to be in the order: Ni>Cd>Pb>Cu>Cr; stem Ni>Pb>Cu>Cd>Cr; and leaf Ni>Cd>Cu>Pb>Cr. The highest amount adsorbed was Ni (root>leaf>stem). Data from this laboratory demonstrated that Ni is sequestered mostly in the roots, where concentrations can be as high as 428.4 ng/g dry wt., when 1-year-old seedlings were treated with Ni (2000 mg/l) in pot culture experiments, compared to 7.63 ng/g dry wt., control (garden and greenhouse soil) topsoil where Ni was present in trace amounts. This proves that the root biomass of Q. ilex has the capacity for complexing Ni. Cr exhibited the least adsorption values for all the three types of phytomass compared to other metals. The trend of adsorption of the phytomass was similar for Ni and Cd, i.e. root>leaf>stem. Desorption with 10 mM Na(4) EDTA was effective (55-90%) and, hence, there exists the possibility of recycling the phytomass. The biosorption results of recycled phytomass suggest that the selected adsorbents are re-usable. The advantages and potential of the Q. ilex phytomass as a biofilter of toxic trace metals, the scope and need for enhancing the efficiency of the Q. ilex phytomass as an adsorbent of metals are presented. PMID:15092842

  14. RESOLVING NEIGHBORHOOD-SCALE AIR TOXICS MODELING: A CASE STUDY IN WILMINGTON, CALIFORNIA

    EPA Science Inventory

    Air quality modeling is useful for characterizing exposures to air pollutants. While models typically provide results on regional scales, there is a need for refined modeling approaches capable of resolving concentrations on the scale of tens of meters, across modeling domains 1...

  15. 75 FR 6336 - Approval and Promulgation of Air Quality Implementation Plans; West Virginia; Removal of NOX

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-09

    ... West Virginia that removes West Virginia's nitrogen oxides (NOx) SIP Call rules. In the Final Rules...; Removal of NOX SIP Call Rules AGENCY: Environmental Protection Agency (EPA). ACTION: Proposed rule... without prior proposal because the Agency views this as a noncontroversial submittal and anticipates...

  16. 77 FR 44149 - Approval and Promulgation of Air Quality Implementation Plans; Virginia; Removal of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-27

    ... action to remove four internal administrative requirements from the regulation for the control of motor... Administrative Requirements From the Regulation for the Control of Motor Vehicle Emissions in Northern Virginia... Virginia. This revision removes four internal State administrative requirements from the Virginia...

  17. THE IMPACT OF SHRINKING HANFORD BOUNDARIES ON PERMITS FOR TOXIC AIR POLLUTANT EMISSIONS FROM THE HANFORD 200 WEST AREA

    SciTech Connect

    JOHNSON, R.E.

    2005-11-09

    This presentation (CE-580. Graduate Seminar) presents a brief description of an approach to use a simpler dispersion modeling method (SCREEN3) in conjunction with joint frequency tables for Hanford wind conditions to evaluate the impacts of shrinking the Hanford boundaries on the current permits for facilities in the 200 West Area. To fulfill requirements for the graduate student project (CE-702. Master's Special Problems), this evaluation will be completed and published over the next two years. Air toxic emissions play an important role in environmental quality and require a state approved permit. One example relates to containers or waste that are designated as Transuranic Waste (TRU), which are required to have venting devices due to hydrogen generation. The Washington State Department of Ecology (Ecology) determined that the filters used did not meet the definition of a ''pressure relief device'' and that a permit application would have to be submitted by the Central Waste Complex (CWC) for criteria pollutant and toxic air pollutant (TAP) emissions in accordance with Washington Administrative Code (WAC) 173-400 and 173-460. The permit application submitted in 2000 to Ecology used Industrial Source Code III (ISCIII) dispersion modeling to demonstrate that it was not possible for CWC to release a sufficient quantity of fugitive Toxic Air Pollutant emissions that could exceed the Acceptable Source Impact Levels (ASILs) at the Hanford Site Boundary. The modeled emission rates were based on the diurnal breathing in and out through the vented drums (approximately 20% of the drums), using published vapor pressure, molecular weight, and specific gravity data for all 600+ compounds, with a conservative estimate of one exchange volume per day (208 liters per drum). Two permit applications were submitted also to Ecology for the Waste Receiving and Processing Facility and the T Plant Complex. Both permit applications were based on the Central Waste Complex approach, and

  18. The relationship bettween composition and toxicity of tannery wastewater.

    PubMed

    Cotman, M; Zagorc-Koncan, J; Zgajnar-Gotvajn, A

    2004-01-01

    Key toxic components have been identified in pre-treated tannery wastewater with fractionation of samples through chemical and physical means (filtration, air stripping, adsorption on activated carbon,...). The goal of each fractionation step was to reduce the toxicity due to a specific group of chemicals and compare the results to the toxicity present in the unaltered sample. Toxicity short-term tests with the invertebrate Daphnia magna and thebacterial luminescence inhibition test with Vibrio fischeri were used in combination with chemical analyses. During the toxicity identification and evaluation fractionation, a portion of the sample was pressure filtered. Treated samples contained less organic pollution and metals and were less toxic especially to Daphnia magna. For the removal of ammonia the second portion of sample was air-stripped at different pH levels. We removed 84% of ammonia at pH 11; the toxicity to both organisms decreased but ammonia did not have a deciding effect on the toxicity of tannery wastewater when the organic load was still present. The most successful procedure for toxicity removal was adsorption on powdered activated carbon. We removed organic pollution detected as COD, organic nitrogen compounds and part of the metals. Zeolite treatment was a little less successful for removing ammonia than air-stripping.

  19. Impact of HVAC filter on indoor air quality in terms of ozone removal and carbonyls generation

    NASA Astrophysics Data System (ADS)

    Lin, Chi-Chi; Chen, Hsuan-Yu

    2014-06-01

    This study aims at detecting ozone removal rates and corresponding carbonyls generated by ozone reaction with HVAC filters from various building, i.e., shopping mall, school, and office building. Studies were conducted in a small-scale environmental chamber. By examining dust properties including organic carbon proportion and specific surface area of dusts adsorbed on filters along with ozone removal rates and carbonyls generation rate, the relationship among dust properties, ozone removal rates, and carbonyls generation was identified. The results indicate a well-defined positive correlation between ozone removal efficiency and carbonyls generation on filters, as well as a positive correlation among the mass of organic carbon on filters, ozone removal efficiency and carbonyls generations.

  20. "Air Toxics under the Big Sky": Examining the Effectiveness of Authentic Scientific Research on High School Students' Science Skills and Interest

    ERIC Educational Resources Information Center

    Ward, Tony J.; Delaloye, Naomi; Adams, Earle Raymond; Ware, Desirae; Vanek, Diana; Knuth, Randy; Hester, Carolyn Laurie; Marra, Nancy Noel; Holian, Andrij

    2016-01-01

    "Air Toxics Under the Big Sky" is an environmental science outreach/education program that incorporates the Next Generation Science Standards (NGSS) 8 Practices with the goal of promoting knowledge and understanding of authentic scientific research in high school classrooms through air quality research. This research explored: (1)…

  1. PRELIMINARY FINDINGS ON THE ASSESSMENT OF POTENTIAL CAR-RELATED OCCUPATIONAL PM AND AIR TOXIC EXPOSURE TO PATROL TROOPERS (COPP STUDY)

    EPA Science Inventory

    In-vehicle, roadside and community-based measurements of particulate matter (PM) and select air toxics were measured as part of a study involving patrol cars from the North Carolina Highway Patrol. One goal of this study was to characterize PM and related air pollutant concentra...

  2. Future research needs associated with the assessment of potential human health risks from exposure to toxic ambient air pollutants.

    PubMed Central

    Möller, L; Schuetzle, D; Autrup, H

    1994-01-01

    This paper presents key conclusions and future research needs from a Workshop on the Risk Assessment of Urban Air, Emissions, Exposure, Risk Identification, and Quantification, which was held in Stockholm during June 1992 by 41 participants from 13 countries. Research is recommended in the areas of identification and quantification of toxics in source emissions and ambient air, atmospheric transport and chemistry, exposure level assessment, the development of improved in vitro bioassays, biomarker development, the development of more accurate epidemiological methodologies, and risk quantification techniques. Studies are described that will be necessary to assess and reduce the level of uncertainties associated with each step of the risk assessment process. International collaborative research efforts between industry and government organizations are recommended as the most effective way to carry out this research. PMID:7529703

  3. Aerosolized ZnO nanoparticles induce toxicity in alveolar type II epithelial cells at the air-liquid interface

    SciTech Connect

    Xie, Yumei; Williams, Nolann G.; Tolic, Ana; Chrisler, William B.; Teeguarden, Justin G.; Maddux, Bettye L.; Pounds, Joel G.; Laskin, Alexander; Orr, Galya

    2012-01-20

    The majority of in vitro studies characterizing the impact of engineered nanoparticles (NPs) on cells that line the respiratory tract were conducted in cells exposed to NPs in suspension. This approach introduces processes that are unlikely to occur during inhaled NP exposures in vivo, such as the shedding of toxic doses of dissolved ions. ZnO NPs are used extensively and pose significant sources for human exposure. Exposures to airborne ZnO NPs can induce adverse effects, but the relevance of the dissolved Zn2+ to the observed effects in vivo is still unclear. Our goal was to mimic in vivo exposures to airborne NPs and decipher the contribution of the intact NP from the contribution of the dissolved ions to airborne ZnO NP toxicity. We established the exposure of alveolar type II epithelial cells to aerosolized NPs at the air-liquid interface (ALI), and compared the impact of aerosolized ZnO NPs and NPs in suspension at the same cellular doses, measured as the number of particles per cell. By evaluating membrane integrity and cell viability 6 and 24 hours post exposure we found that aerosolized NPs induced toxicity at the ALI at doses that were in the same order of magnitude as doses required to induce toxicity in submersed cultures. In addition, distinct patterns of oxidative stress were observed in the two exposure systems. These observations unravel the ability of airborne ZnO NPs to induce toxicity without the contribution of dissolved Zn2+ and suggest distinct mechanisms at the ALI and in submersed cultures.

  4. AIR STRIPPING AND OFF-GAS ADSORPTION FOR THE REMOVAL OF MTBE FROM DRINKING WATER

    EPA Science Inventory

    Methyl-tertiary butyl ether (MTBE) is a synthetic organic chemical, primarily used for oxgenating fuel. The 1990 Federal Clean Air Act Amendments mandated the use of fuel oxgenates in areas where air quality did not meet national standards, which led to widespread use of MTBE in...

  5. [Environmental investigation of ground water contamination at Wright-Patterson Air Force Base, Ohio]. Volume 9, Removal action system design

    SciTech Connect

    Not Available

    1992-04-01

    This Removal Action System Design has been prepared as a Phase I Volume for the implementation of the Phase II removal action at Wright-Patterson Air Force Base (WPAFB) near Dayton, Ohio. The objective of the removal action is to prevent, to the extent practicable, the migration of ground water contaminated with chlorinated volatile organic compounds (VOCS) across the southwest boundary of Area C. The Phase 1, Volume 9 Removal Action System Design compiles the design documents prepared for the Phase II Removal Action. These documents, which are presented in Appendices to Volume 9, include: Process Design, which presents the 30 percent design for the ground water treatment system (GWTS); Design Packages 1 and 2 for Earthwork and Road Construction, and the Discharge Pipeline, respectively; no drawings are included in the appendix; Design Package 3 for installation of the Ground Water Extraction Well(s); Design Package 4 for installation of the Monitoring Well Instrumentation; and Design Package 5 for installation of the Ground Water Treatment System; this Design Package is incorporated by reference because of its size.

  6. Clear and present danger? The use of a yeast biosensor to monitor changes in the toxicity of industrial effluents subjected to oxidative colour removal treatments.

    PubMed

    Keenan, Patrick O; Knight, Andrew W; Billinton, Nicholas; Cahill, Paul A; Dalrymple, Ian M; Hawkyard, Christopher J; Stratton-Campbell, Duncan; Walmsley, Richard M

    2007-12-01

    Discharges of coloured effluents into surface waters provide conspicuous evidence of the impact of industry on the environment. The textile industry is an obvious candidate for sources of such discharges. Conventional treatment methods appear to alleviate this situation by removing colour, however the affect on toxicity is less obvious. The objective of this study was to examine the changes in effluent toxicity during the course of two alternative wastewater treatment methods, ozonation and electrochemical oxidation, using a novel toxicity biosensor, GreenScreen EM. The biosensor is capable of measuring both general acute toxicity (cytotoxicity), and more specifically genotoxicity, that is damage to a cell's DNA structure, replication or distribution, caused by substances that may be mutagenic and/or carcinogenic. The biosensor utilises a modified strain of the brewers yeast Saccharomyces cerevisiae, incorporating a gene encoding green fluorescent protein (GFP) linked to the inducible promoter of the DNA damage responsive RAD54 gene. Upon exposure to a genotoxin, the production of GFP is up-regulated in parallel with RAD54, and the resulting cellular fluorescence provides a measure of genotoxicity. Acute toxicity is simultaneously determined by monitoring relative total growth of the cell culture during incubation. The results presented in this paper show that a reduction in colouration does not necessarily correspond to a reduction in effluent toxicity.

  7. ENVIRONMENTAL CONTROL OF TOXIC METAL AIR EMISSIONS FROM THE COMBUSTION OF COAL AND WASTES

    EPA Science Inventory

    The paper is concerned with the partitioning of toxic metals (e.g., arsenic, selenium, mercury, chromium, lead, and cadmium) during combustion, and with the mitigation of their effect on the environment using high-temperature sorbents. The paper is divided into three parts: (1) t...

  8. Air toxics and epigenetic effects: ozone altered microRNAs in the sputum of human subjects

    EPA Science Inventory

    Ozone (03) is a criteria air pollutant that is associated with numerous adverse health effects, including altered respiratory immune responses. Despite its deleterious health effects, possible epigenetic mechanisms underlying 03-induced health effects remain understudied. MicroRN...

  9. AIR PARTICULATE POLLUTION CARDIOVASCULAR TOXICITY: HAZARD IDENTIFICATION AND MECHANISMS OF ACTION

    EPA Science Inventory


    The overall weight of evidence from epidemiological studies has shown statistical associations between air particulate pollution exposure and mortality\\morbidity particularly within individuals with cardiovascular disease (1-4). Identification of causal particle properties ...

  10. The removal process of 2,2-dichloroacetamide (DCAcAm), a new disinfection by-product, in drinking water treatment process and its toxicity on zebrafish.

    PubMed

    Lin, Tao; Zhou, Dongju; Yu, Shilin; Chen, Wei

    2016-09-01

    The removal process of 2,2-dichloroacetamide (DCAcAm), a new disinfection by-product (DBP) in conventional drinking water treatment plant (C-DWTP) and advanced DWTP (ADWTP) was studied with newly maximum formation potential (MFP) process. It was demonstrated that the advanced treatment displayed greater removal efficiency towards DCAcAm formation potential (MFP) than the conventional treatment. The hydrophilic natural organic matter and natural organic matter with molecular weight <1 kDa or >10 kDa leaded to more DCAcAm formation, and the aromatic protein was inferred as one part of DCAcAm precursor. DCAcAm was found to cause delayed development and malformation to zebrafish embryos at embryonic growth stage. Compared with heart toxicity, it caused a significant neuron toxicity. It also could cause the acute DNA damage to adult zebrafish, which should be extremely cautioned.

  11. Air sparging/high vacuum extraction to remove chlorinated solvents in groundwater and soil

    SciTech Connect

    Phelan, J.M.; Gilliat, M.D.

    1998-11-01

    An air sparging and high vacuum extraction was installed as an alternative to a containment pump and treat system to reduce the long-term remediation schedule. The site is located at the DOE Mound facility in Miamisburg, Ohio, just south of Dayton. The air sparging system consists of 23 wells interspersed between 17 soil vapor extraction wells. The SVE system has extracted about 1,500 lbs of VOCs in five months. The air sparging system operated for about 6 weeks before shutdown due to suspected biochemical fouling. Technical data are presented on the operating characteristics of the system.

  12. Removal of volatile organic compounds from air streams by making use of a microwave plasma burner with reverse vortex flows

    NASA Astrophysics Data System (ADS)

    Kim, Ji H.; Ma, Suk H.; Cho, Chang H.; Hong, Yong C.; Ahn, Jae Y.

    2014-01-01

    We developed an atmospheric-pressure microwave plasma burner for removing volatile organic compounds (VOCs) from polluted air streams. This study focused on the destruction of the VOCs in the high flow rate polluted streams required for industrial use. Plasma flames were sustained by injecting liquefied natural gas (LNG), which is composed of CH4, into the microwave plasma torch. With its high temperature and high density of atomic oxygen, the microwave torch attained nearly complete combustion of LNG, thereby providing a large-volume, high-temperature plasma flame. The plasma flame was applied to reactors in which the polluted streams were in one of two vortex flows: a conventional vortex reactor (CVR) or a reverse vortex reactor (RVR). The RVR, using a plasma power of 2 kW and an LNG flow of 20 liters per minute achieved a destruction removal efficiency (DRE) of 98% for an air flow rate of 5 Nm3/min polluted with 550 pm of VOCs.. For the same experimental parameters, the CVR provided a DRE of 90.2%. We expect that this decontamination system will prove effective in purifying contaminated air at high flow rates.

  13. An evaluation of EPA’s National-Scale Air Toxics Assessment (NATA): Comparison with benzene measurements in Detroit, Michigan

    NASA Astrophysics Data System (ADS)

    George, Barbara Jane; Schultz, Bradley D.; Palma, Ted; Vette, Alan F.; Whitaker, Donald A.; Williams, Ronald W.

    2011-06-01

    The U.S. EPA periodically evaluates ambient concentrations, human exposures, and health risks for 180 hazardous air pollutants plus diesel particulate matter using modeled estimates from the National-Scale Air Toxics Assessment (NATA). NATA publishes estimates at the spatial resolution of U.S. Census tracts, which are subdivisions of a county. These local scale, model-predicted estimates from NATA are used extensively in community-based assessments; however, evaluation of NATA's ambient concentrations and human exposure estimates against measurement data has been limited to date. This paper compares modeled annual average benzene results from the 2002 NATA with measured results from the 2004 to 2007 Detroit Exposure and Aerosol Research Study (DEARS) as a case study of the quality of NATA results. NATA model estimates support community-scale characterization and assessment. Benzene is particularly important as it was estimated by the 2002 NATA as the largest single air toxic pollutant in terms of cancer risk in the U.S. We found that the average ambient concentrations of benzene predicted by NATA were within 5 percent, on average, of the 24-h integrated average ambient concentrations measured in DEARS. The NATA human exposure estimates, which include only outdoor sources for benzene, were, on average, approximately half the measured breathing zone concentrations from DEARS. Our analyses support that the factors driving higher DEARS personal benzene concentrations relative to the NATA predicted exposure values are likely due, at least in part, to indoor sources. This work points to further community-scale modeling research to improve characterizations and assessments of human exposures.

  14. Hydrogen sulfide removal from air by Acidithiobacillus thiooxidans in a trickle bed reactor.

    PubMed

    Ramirez, M; Gómez, J M; Cantero, D; Páca, J; Halecký, M; Kozliak, E I; Sobotka, M

    2009-09-01

    A strain of Acidithiobacillus thiooxidans immobilized in polyurethane foam was utilized for H(2)S removal in a bench-scale trickle-bed reactor, testing the limits of acidity and SO(4) (2-) accumulation. The use of this acidophilic strain resulted in remarkable stability in the performance of the system. The reactor maintained a >98-99 % H(2)S removal efficiency for c of up to 66 ppmv and empty bed residence time Removal of >98 % H(2)S was achieved under steady-state conditions, over the pH range of 0.44-7.30. Despite the accumulation of acidity and SO(4) (2-) (up to 97 g/L), the system operated without inhibition.

  15. Influence of liquid and gas flow rates on sulfuric acid mist removal from air by packed bed tower

    PubMed Central

    2012-01-01

    The possible emission of sulfuric acid mists from a laboratory scale, counter-current packed bed tower operated with a caustic scrubbing solution was studied. Acid mists were applied through a local exhaust hood. The emissions from the packed bed tower were monitored in three different categories of gas flow rate as well as three liquid flow rates, while other influencing parameters were kept almost constant. Air sampling and sulfuric acid measurement were carried out iso-kinetically using USEPA method 8. The acid mists were measured by the barium-thorin titration method. According to the results when the gas flow rate increased from 10 L/s to 30 L/s, the average removal efficiency increased significantly (p < 0.001) from 76.8 ± 1.8% to 85.7 ± 1.2%. Analysis of covariance method followed by Tukey post-hoc test of 92 tests did not show a significant change in removal efficiency between liquid flow rates of 1.5, 2.5 and 3.5 L/min (p = 0.811). On the other hand, with fixed pressure loss across the tower, by increasing the liquid/gas (L/G) mass ratio, the average removal efficiency decreased significantly (p = 0.001) from 89.9% at L/G of <2 to 83.1% at L/G of 2–3 and further to 80.2% at L/G of >3, respectively. L/G of 2–3 was recommended for designing purposes of a packed tower for sulfuric acid mists and vapors removal from contaminated air stream. PMID:23369487

  16. Electricity generation and nutrients removal from high-strength liquid manure by air-cathode microbial fuel cells.

    PubMed

    Lin, Hongjian; Wu, Xiao; Nelson, Chad; Miller, Curtis; Zhu, Jun

    2016-01-01

    Air-cathode microbial fuel cells (MFCs) are widely tested to recover electrical energy from waste streams containing organic matter. When high-strength wastewater, such as liquid animal manure, is used as a medium, inhibition on anode and cathode catalysts potentially impairs the effectiveness of MFC performance in power generation and pollutant removal. This study evaluated possible inhibitive effects of liquid swine manure components on MFC power generation, improved liquid manure-fed MFCs performance by pretreatment (dilution and selective adsorption), and modeled the kinetics of organic matter and nutrients removal kinetics. Parameters monitored included pH, conductivity, chemical oxygen demand (COD), volatile fatty acids (VFAs), total ammoniacal nitrogen (TAN), nitrite, nitrate, and phosphate concentrations. The removals of VFA and TAN were efficient, indicated by the short half-life times of 4.99 and 7.84 d, respectively. The mechanism for phosphate decrease was principally the salt precipitation on cathode, but the removal was incomplete after 42-d operation. MFC with an external resistor of 2.2 kΩ and fed with swine wastewater generated relatively small power (28.2 μW), energy efficiency (0.37%) and Coulombic efficiency (1.5%). Dilution of swine wastewater dramatically improved the power generation as the inhibitory effect was decreased. Zeolite and granular activated carbon were effective in the selective adsorption of ammonia or organic matter in swine wastewater, and so substantially improved the power generation, energy efficiency, and Coulombic efficiency. A smaller external resistor in the circuit was also observed to promote the organic matter degradation and thus to shorten the treatment time. Overall, air-cathode MFCs are promising for generating electrical power from livestock wastewater and meanwhile reducing the level of organic matter and nutrients.

  17. Electricity generation and nutrients removal from high-strength liquid manure by air-cathode microbial fuel cells.

    PubMed

    Lin, Hongjian; Wu, Xiao; Nelson, Chad; Miller, Curtis; Zhu, Jun

    2016-01-01

    Air-cathode microbial fuel cells (MFCs) are widely tested to recover electrical energy from waste streams containing organic matter. When high-strength wastewater, such as liquid animal manure, is used as a medium, inhibition on anode and cathode catalysts potentially impairs the effectiveness of MFC performance in power generation and pollutant removal. This study evaluated possible inhibitive effects of liquid swine manure components on MFC power generation, improved liquid manure-fed MFCs performance by pretreatment (dilution and selective adsorption), and modeled the kinetics of organic matter and nutrients removal kinetics. Parameters monitored included pH, conductivity, chemical oxygen demand (COD), volatile fatty acids (VFAs), total ammoniacal nitrogen (TAN), nitrite, nitrate, and phosphate concentrations. The removals of VFA and TAN were efficient, indicated by the short half-life times of 4.99 and 7.84 d, respectively. The mechanism for phosphate decrease was principally the salt precipitation on cathode, but the removal was incomplete after 42-d operation. MFC with an external resistor of 2.2 kΩ and fed with swine wastewater generated relatively small power (28.2 μW), energy efficiency (0.37%) and Coulombic efficiency (1.5%). Dilution of swine wastewater dramatically improved the power generation as the inhibitory effect was decreased. Zeolite and granular activated carbon were effective in the selective adsorption of ammonia or organic matter in swine wastewater, and so substantially improved the power generation, energy efficiency, and Coulombic efficiency. A smaller external resistor in the circuit was also observed to promote the organic matter degradation and thus to shorten the treatment time. Overall, air-cathode MFCs are promising for generating electrical power from livestock wastewater and meanwhile reducing the level of organic matter and nutrients. PMID:26654000

  18. Role of air in growth and production of toxic shock syndrome toxin 1 by Staphylococcus aureus in experimental cotton and rayon tampons.

    PubMed

    Fischetti, V A; Chapman, F; Kakani, R; James, J; Grun, E; Zabriskie, J B

    1989-01-01

    Rayon and cotton fibers of the type used in the manufacture of tampons were extracted for 6 hours in isopropyl alcohol in a soxhlet apparatus to remove all finishes from the fiber surface. The fibers were used to produce experimental tampons of commercial design. Using a syringe method, the tampons were saturated with diluted staphylococci in brain-heart infusion medium and incubated at 37 degrees C. Spent medium was expressed from the tampons and analyzed for growth of staphylococci and production of toxic shock syndrome toxin 1 (TSST-1). Results revealed no statistical difference in the production of TSST-1 by cells grown in rayon or cotton. However, a significant increase in TSST-1 production was observed in tampon cultures when compared with medium controls. When similar experiments were performed with tampons saturated with nitrogen, a significant decrease in TSST-1 production was observed when compared with air-saturated tampons. The results indicate that the oxygen normally present in tampons plays a significant role in modulating the production of TSST-1.

  19. Large-scale high-efficiency air stripper and recovery well network for removing volatile organic chlorocarbons from ground water

    SciTech Connect

    Boone, L F; Lorfenz, R; Muska, C F; Steele, J L

    1986-05-01

    The Savannah River Plant (SRP) produces special nuclear materials for the US Government. Since 1958, chemical wastes generated by an aluminum forming/metal finishing process used to manufacture fuel and target assemblies were discharged to a settling basin. This process waste stream contained acids, alkalis, metals, and chlorinated degreasing solvents. In 1981, these solvents, specifically trichloroethylene and tetrachloroethylene, were discovered in monitor wells near the settling basin. A monitor well network was installed to define the vertical and horizontal extent of the plume. The current inventory of total chlorocarbons in the saturated zone is approximately 360,000 pounds within the 100 ppB contour interval. During 1983, air stripping technology was evaluated to remove these solvents from the ground water. A 20-gpm ground water pilot air stripper with one recovery well was tested. Performance data from this unit were then used to design a 50-gpm production prototype air stripper. This unit demonstrated that degreaser solvent concentrations in ground water could be reduced from 120,000 ppB to less than the detection limit of 1 ppB. Data from these two units were then used to design an air stripper column that would process contaminated ground water at a rate of 400 gpm. Water is fed to this column from a network of 11 recovery wells. These wells were located in the zone of contamination, as defined by analytical and numerical modeling techniques. This system has been operational since April 1985. To date, over 65,000 pounds of chlorinated degreaser solvents have been removed from an underlying aquifer. The effects of this program on the hydraulic gradient and contamination movement are currently being evaluated. The purpose of this paper is to describe the ground water remediation program at the Savannah River Plant.

  20. Enhanced, multi criteria based site selection to measure mobile source toxic air pollutants

    EPA Science Inventory

    Research studies being conducted by the U.S. Environmental Protection Agency in collaboration with the U.S. Federal Highway Administration are designed to establish relationships between concentrations of highway vehicle air pollutants and variations in these concentrations as a ...

  1. DETECTION AND IDENTIFICATION OF TOXIC AIR POLLUTANTS USING AIRBORNE LWIR HYPERSPECTRAL IMAGING

    EPA Science Inventory

    Gaseous releases from petrochemical, refinery, and electrical production facilities can contribute to regional air quality problems. Fugitive emissions or leaks can be costly to industry in terms of lost materials and products. Ground-based sampling and monitoring for leaks are t...

  2. Modeling and Impacts of Traffic Emissions on Air Toxics Concentrations near Roadways

    EPA Science Inventory

    The dispersion formulation incorporated in the U.S. Environmental Protection Agency’s AERMOD regulatory dispersion model is used to estimate the contribution of traffic-generated emissions of select VOCs – benzene, 1,3-butadiene, toluene – to ambient air concentrations at downwin...

  3. CO-DEPENDENCIES OF REACTIVE AIR TOXIC AND CRITERIA POLLUTANTS ON EMISSION REDUCTIONS

    EPA Science Inventory

    It is important to understand the effect of emission controls on the concentrations of ozone, PM2.5, and hazardous air pollutants simultaneously, in order to evaluate the full range of both health related and economic effects. Until recently, the capability of simultan...

  4. COMPARATIVE TOXICITY OF AIR POLLUTION PARTICLES COLLECTED FROM DIFFERENT GEOGRAPHICAL LOCATIONS

    EPA Science Inventory

    Air pollution particulate matter (PM) is responsible for more than 500,000 deaths worldwide each year. PM pollution is a complex mixture containing dozens of different compounds; the composition of PM can vary dramatically among different locations depending on the sources of pa...

  5. CHARACTERIZATION OF AIR TOXICS FROM AN OIL-FIRED FIRETUBE BOILER

    EPA Science Inventory

    Tests were conducted on a commercially available firetube package boiler running on #2 through #6 oils to determine the emissions levels of hazardous air pollutants (HAPs) from the combustion of four fuel oils. Flue gas was sampled to determine levels of volatile and semivolatile...

  6. DEMONSTRATION BULLETIN: IN-SITU STEAM/HOT AIR SOIL STRIPPING TOXIC TREATMENT (USA) INC.

    EPA Science Inventory

    This technology uses steam and hot air to strip volatile organics from contaminated soil. The treatment equipment is mobile and treats the soil in-situ without need for soil excavation or transportation. The organic contaminants volatilized from the soil are condensed and col...

  7. 78 FR 65875 - Approval and Promulgation of Air Quality Implementation Plans; Wisconsin; Removal of Gasoline...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-04

    ... FR 34966, EPA proposed to remove the Stage II requirements under NR 420.045 of the Wisconsin...'' subject to review by the Office of Management and Budget under Executive Order 12866 (58 FR 51735, October... Executive Order 13132 (64 FR 43255, August 10, 1999); is not an economically significant regulatory...

  8. Nonradioactive air emissions notice of construction for removal of 340A building tank solids

    SciTech Connect

    Perry, J.K.

    1997-03-28

    The 340 Complex is a less-than-90-day storage unit for mixed waste generated on the Hanford Site. The 340 Complex receives liquid waste from various buildings in the 300 Area via underground transfer lines, or by containers from generators supporting Hanford Site programs. The tanks used for waste storage at the 340 Complex include two 57 kiloliter tanks within the 340 Underground Storage Vault and six 30 kiloliter tanks within the 340A building. The two underground vault tanks provide primary waste storage while the six tanks in the 340A building provide reserve storage capacity. The 340A Building tanks are not equipped with agitation devices and/or equipment. Consequently, past usage of the tanks has resulted in the formation, deposition, and settling of waste water solids. The deposited tank solids contain radioactive material that represent a source of radiation exposure to workers. For as low as reasonably achievable (ALARA) purposes, the solids must be removed periodically from the tanks. The most recent tank solids removal effort occurred in the early 1980s. The removal of solids from the 340A building tanks constitutes a modification, in accordance with WAC 173-460-020(14), and, in accordance with WAC 173-460-040, the proposed activities are subject to New Source Review. In accordance with WAC 173-460 and WAC 173-400, this document serves as a Notice of Construction (NOC) for periodically removing solids from the 340A Building tanks.

  9. Efficient salt removal in a continuously operated upflow microbial desalination cell with an air cathode.

    PubMed

    Jacobson, Kyle S; Drew, David M; He, Zhen

    2011-01-01

    Microbial desalination cells (MDCs) hold great promise for drinking water production because of potential energy savings during the desalination process. In this study, we developed a continuously operated MDC--upflow microbial desalination cell (UMDC) for the purpose of salt removal. During the 4-month operation, the UMDC constantly removed salts and generated bio-electricity. At a hydraulic retention time (HRT) of 4 days (salt solution) and current production of ∼62 mA, the UMDC was able to remove more than 99% of NaCl from the salt solution that had an initial salt concentration of 30 g total dissolved solids (TDS)/L. In addition, the TDS removal rate was 7.50 g TDSL(-1)d(-1) (salt solution volume) or 5.25 g TDSL(-1)d(-1) (wastewater volume), and the desalinated water met the drinking water standard, in terms of TDS concentration. A high charge transfer efficiency of 98.6% or 81% was achieved at HRT 1 or 4d. The UMDC produced a maximum power density of 30.8 W/m(3). The phenomena of bipolar electrodialysis and proton transport in the UMDC were discussed. These results demonstrated the potential of the UMDC as either a sole desalination process or a pre-desalination reactor for downstream desalination processes.

  10. Heme oxygenase-1 protects endothelial cells from the toxicity of air pollutant chemicals.

    PubMed

    Lawal, Akeem O; Zhang, Min; Dittmar, Michael; Lulla, Aaron; Araujo, Jesus A

    2015-05-01

    Diesel exhaust particles (DEPs) are a major component of diesel emissions, responsible for a large portion of their toxicity. In this study, we examined the toxic effects of DEPs on endothelial cells and the role of DEP-induced heme oxygenase-1 (HO-1) expression. Human microvascular endothelial cells (HMECs) were treated with an organic extract of DEPs from an automobile engine (A-DEP) or a forklift engine (F-DEP) for 1 and 4h. ROS generation, cell viability, lactate dehydrogenase leakage, expression of HO-1, inflammatory genes, cell adhesion molecules and unfolded protein respone (UPR) gene were assessed. HO-1 expression and/or activity were inhibited by siRNA or tin protoporphyrin (Sn PPIX) and enhanced by an expression plasmid or cobalt protoporphyrin (CoPPIX). Exposure to 25μg/ml of A-DEP and F-DEP significantly induced ROS production, cellular toxicity and greater levels of inflammatory and cellular adhesion molecules but to a different degree. Inhibition of HO-1 enzymatic activity with SnPPIX and silencing of the HO-1 gene by siRNA enhanced DEP-induced ROS production, further decreased cell viability and increased expression of inflammatory and cell adhesion molecules. On the other hand, overexpression of the HO-1 gene by a pcDNA 3.1D/V5-HO-1 plasmid significantly mitigated ROS production, increased cell survival and decreased the expression of inflammatory genes. HO-1 expression protected HMECs from DEP-induced prooxidative and proinflammatory effects. Modulation of HO-1 expression could potentially serve as a therapeutic target in an attempt to inhibit the cardiovascular effects of ambient PM.

  11. 78 FR 68365 - Approval and Promulgation of Air Quality Implementation Plans; Virginia; Removal of the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-14

    ... email. The www.regulations.gov Web site is an ``anonymous access'' system, which means EPA will not know... available only in hard copy form. Publicly available docket materials are available either electronically in www.regulations.gov or in hard copy during normal business hours at the Air Protection Division,...

  12. COST ANALYSIS OF ACTIVATED CARBON VERSUS PHOTOCATALYTIC OXIDATION FOR REMOVING ORGANIC COMPOUNDS FROM INDOOR AIR

    EPA Science Inventory

    A cost comparison has been conducted of 1 m3/s indoor air cleaners using granular activated carbon (GAC) vs. photocatalytic oxidation (PCO) for treating a steady-state inlet volatile organic compound (VOC) concentration of 0.3 mg/m3. The commercial GAC unit was costed assuming t...

  13. Gas-fired boiler and turbine air toxics summary report. Final report, January-September 1995

    SciTech Connect

    Rossi-Lane, C.; Stein, D.; Himes, R.

    1996-08-01

    The objective of the report is to provide a summary of the criteria pollutants and hazardous air pollutants (HAPs) emitted from a variety of gas-fired stationary sources including utility boilers, utility turbines, and turbines used for natural gas transmission. The report provides emission factors for each compound measured as a function of load to support general use during the preparation of Title V permit applications.

  14. Simplified preparation of TO14 and Title III air toxic standards using a Windows software package and dynamic dilution schemes

    SciTech Connect

    Cardin, D.B.; Galoustian, E.A.

    1994-12-31

    The preparation of Air Toxic standards in the laboratory can be performed using several methods. These include injection of purge and trap standards, static dilution from pure compounds, and dynamic dilution from NIST traceable standards. A software package running under Windows has been developed that makes calculating dilution parameters for even complex mixtures fast and simple. Compound parameters such are name, molecular weight, boiling point, and density are saved in a data base for later access. Gas and liquid mixtures can be easily defined and saved as an inventory item, with preparation screens that calculate appropriate transfer volumes of each analyte. These mixtures can be utilized by both the static and dynamic dilution analysis windows to calculate proper flow rates and injection volumes for obtaining requested concentrations. A particularly useful approach for making accurate polar VOC standards will be presented.

  15. Heme oxygenase-1 protects endothelial cells from the toxicity of air pollutant chemicals

    SciTech Connect

    Lawal, Akeem O.; Zhang, Min; Dittmar, Michael; Lulla, Aaron; Araujo, Jesus A.

    2015-05-01

    Diesel exhaust particles (DEPs) are a major component of diesel emissions, responsible for a large portion of their toxicity. In this study, we examined the toxic effects of DEPs on endothelial cells and the role of DEP-induced heme oxygenase-1 (HO-1) expression. Human microvascular endothelial cells (HMECs) were treated with an organic extract of DEPs from an automobile engine (A-DEP) or a forklift engine (F-DEP) for 1 and 4 h. ROS generation, cell viability, lactate dehydrogenase leakage, expression of HO-1, inflammatory genes, cell adhesion molecules and unfolded protein respone (UPR) gene were assessed. HO-1 expression and/or activity were inhibited by siRNA or tin protoporphyrin (Sn PPIX) and enhanced by an expression plasmid or cobalt protoporphyrin (CoPPIX). Exposure to 25 μg/ml of A-DEP and F-DEP significantly induced ROS production, cellular toxicity and greater levels of inflammatory and cellular adhesion molecules but to a different degree. Inhibition of HO-1 enzymatic activity with SnPPIX and silencing of the HO-1 gene by siRNA enhanced DEP-induced ROS production, further decreased cell viability and increased expression of inflammatory and cell adhesion molecules. On the other hand, overexpression of the HO-1 gene by a pcDNA 3.1D/V5-HO-1 plasmid significantly mitigated ROS production, increased cell survival and decreased the expression of inflammatory genes. HO-1 expression protected HMECs from DEP-induced prooxidative and proinflammatory effects. Modulation of HO-1 expression could potentially serve as a therapeutic target in an attempt to inhibit the cardiovascular effects of ambient PM. - Highlights: • We examined the role of HO-1 expression on diesel exhaust particle (DEP) in endothelial cells. • DEPs exert cytotoxic and inflammatory effects on human microvascular endothelial cells (HMECs). • DEPs induce HO-1 expression in HMECs. • HO-1 protects against the oxidative stress induced by DEps. • HO-1 attenuates the proinflammatory effects

  16. Novel closed-loop air-stripping process for VOC removal from contaminated water. Final report

    SciTech Connect

    Bhowmick, M.; Sontag, T.K.; Semmens, M.J.

    1990-12-05

    The study presents an approach for the treatment of contaminated groundwater, which includes Volatile Organic Compounds (VOCs) stripped from the water using hollow fiber membranes or using conventional air stripping technology and then the VOCs are oxidized in the gas phase using UV oxidation or a combination of photooxidation and photo-catalysis with Titanium Dioxide (TiO2). The work on the photooxidation of VOCs is applicable to both water and soil treatment techniques, such as air stripping and in-situ vacuum extraction. The study is divided into five major segments: Each segment includes relevant sections on the experimental methods employed, the results from the tests conducted, the development of models, and the conclusions which were drawn from the work.

  17. Plasma-catalyst coupling for volatile organic compound removal and indoor air treatment: a review

    NASA Astrophysics Data System (ADS)

    Thevenet, F.; Sivachandiran, L.; Guaitella, O.; Barakat, C.; Rousseau, A.

    2014-06-01

    The first part of the review summarizes the problem of air pollution and related air-cleaning technologies. Volatile organic compounds in particular have various effects on health and their abatement is a key issue. Different ways to couple non-thermal plasmas with catalytic or adsorbing materials are listed. In particular, a comparison between in-plasma and post-plasma coupling is made. Studies dealing with plasma-induced heterogeneous reactivity are analysed, as well as the possible modifications of the catalyst surface under plasma exposure. As an alternative to the conventional and widely studied plasma-catalyst coupling, a sequential approach has been recently proposed whereby pollutants are first adsorbed onto the material, then oxidized by switching on the plasma. Such a sequential approach is reviewed in detail.

  18. Toxic fear: the management of uncertainty in the wake of the Amsterdam air crash.

    PubMed

    Boin, A; van Duin, M; Heyse, L

    2001-12-14

    This paper examines the management of uncertainty among emergency responders, the media, and the public following the crash of an Israeli cargo plane carrying apparently hazardous cargo in Amsterdam's Bijlmermeer area. While the authorities' management of the emergency created by the initial crash was effective, the long-term crisis management performance was considerably less effective. It is argued that, particularly in hazardous materials emergencies, considerable management attention is required in the long-term aftermath rather than seeking a quick declaration of "all clear" or determination that the crisis is over. This paper examines the roles of all actors in the crisis and addresses the nature of communications in the "disaster after the disaster". The evolution of a "toxic fear" among citizens is documented and the social psychology of crisis management in the aftermath is examined. PMID:11679195

  19. [Life support of the Mars exploration crew. Control of a zeolite system for carbon dioxide removal from space cabin air within a closed air regeneration cycle].

    PubMed

    Chekov, Iu F

    2009-01-01

    The author describes a zeolite system for carbon dioxide removal integrated into a closed air regeneration cycle aboard spacecraft. The continuous operation of a double-adsorbent regeneration system with pCO2-dependable productivity is maintained through programmable setting of adsorption (desorption) semicycle time. The optimal system regulation curve is presented within the space of statistical performance family obtained in quasi-steady operating modes with controlled parameters of the recurrent adsorption-desorption cycle. The automatically changing system productivity ensures continuous intake of concentrated CO2. Control of the adsorption-desorption process is based on calculation of the differential adsorption (desorption) heat from gradient of adsorbent and test inert substance temperatures. The adaptive algorithm of digital control is implemented through the standard spacecraft interface with the board computer system and programmable microprocessor-based controllers. PMID:19621802

  20. Intermedia transfer factors for fifteen toxic pollutants released to air basins in California

    SciTech Connect

    McKone, T.E.; Daniels, J.I.; Chiao, F.F.; Hsieh, D.P.H.

    1993-10-01

    This report provides a summary definition of the intermedia-transfer factors (ITFs). Methods are discussed for estimating these parameters in the absence of measured values, and the estimation errors inherent in these estimation methods are considered. A detailed summary is provided of measured and estimated ITF values for fifteen air contaminants. They include: 1,3 butadiene; cadmium; cellosolve; cellosolve acetate; chloroform; di-2-ethylhexylphthalate; 1,4-dioxame; hexachlorobenzene; inorganic arsenic; inorganic lead; nickel; tetrachloroethylene; toluene; toluene-2,4-diisocyanate; and 1,3-xylene. Recommendations are made regarding the expected value and variance in these values for use in exposure models.

  1. Fukushima radionuclides at air filter and rain water samples collected from Istanbul and their atmospheric removal time.

    PubMed

    Güngör, E; Güngör, N; Yüksel, A; Bağ, G; Orhan, N

    2014-01-01

    Accident at Fukushima Daiichi Nuclear Power Plant (FDNPP) is one of the most serious accident in the world after Chernobyl accident. Following the continuing release of radionuclides in air after FDNPP, traces of fission products ((131)I, (134)Cs and (137)Cs) were recorded in the air filter and rain water samples collected from the ÇNAEM area at İstanbul on 4 April 2011. Airborne particle samples were collected daily in air filters and radio assayed with a high purity germanium detector. The fission products (131)I, (134)Cs and (137)Cs were measured with the maximum activity concentrations of 1.03±0.08, 0.25±0.03 and 0.23±0.03 mBq m(-3), respectively. For determination of the origin of the releases the (134)Cs/(137)Cs ratio was calculated between 1.09 and 0.85. The authors find removal times for (137)Cs of 8.13 d, (134)Cs of 7.25 d and (131)I of 6.82 d.

  2. Efficient photocatalytic removal of NO in indoor air with hierarchical bismuth oxybromide nanoplate microspheres under visible light.

    PubMed

    Ai, Zhihui; Ho, Wingkei; Lee, Shuncheng; Zhang, Lizhi

    2009-06-01

    In this study, hierarchical bismuth oxybromide (BiOBr) nanoplate microspheres were used to remove NO in indoor air under visible light irradiation. The BiOBr microspheres were synthesized with a nonaqueous sol-gel method by using bismuth nitrate and cetyltrimethyl ammonium bromide as the precursors. On degradation of NO under visible light irradiation (lambda > 420 nm) at 400 part-per-billion level, which is typical concentration for indoor air quality, these nonaqueous sol-gel synthesized hierarchical BiOBr microspheres exhibited superior photocatalytic activity to the chemical precipitation synthesized counterpart BiOBr bulk powder and Degussa TiO2 P25 as well as C doped TiO2. The excellent catalytic activity and the long-term activity of nonaqueous sol-gel synthesized BiOBr microspheres were attributed to their special hierarchical structure, which was favorable for the diffusion of intermediates and final products of NO oxidation. Ion chromatograph results confirmed that nitric acid was produced on the surface of BiOBr microspheres during the photooxidation of NO in gas phase. This work suggests that the nonaqueous sol-gel synthesized BiOBr nanoplate microspheres are promising photocatalytic materials for indoor air purification. PMID:19569343

  3. Radioactive air emissions notice of construction fuel removal for 105-KE basin

    SciTech Connect

    Kamberg, L.D., Fluor Daniel Hanford

    1997-02-11

    This document serves as a notice of construction (NOC), pursuant to the requirements of Washington Administrative Code (WAC) 246-247-060, and as a request for approval to construct pursuant to 40 Code of Federal Regulations (CFR) 61.96 for the modifications, installation of new equipment, and fuel removal and sludge relocation activities at 105-KE Basin. The 105-K east reactor and its associated spent nuclear fuel (SNF) storage basin (105-KE Basin) were constructed in the early 1950s and are located in the 100-K Area about 1,400 feet from the Columbia River. The 105-KE Basin contains 1,152 metric tons of SNF stored underwater in 3,673 open canisters. This SNF has been stored for varying periods of time ranging from 8 to 24 years. The 105-KE Basin is constructed of unlined concrete and contains approximately 1.3 million gallons of water with an asphaltic membrane beneath the pool. The fuel is corroding and an estimated 1,700 cubic feet of sludge, containing radionuclides and miscellaneous materials, have accumulated in the basin. The 105-KE Basin has leaked radiologically contaminated water to the soil beneath the basin in the past most likely at the construction joint between the foundation of the basin and the foundation of the reactor. The purpose of the activities described in this Notice of Construction (NOC) is to enable the retrieval and transport of the fuel to the Cold Vacuum Drying Facility (CVDF). This NOC describes modifications, the installation of new equipment, and fuel removal and sludge relocation activities expected to be routine in the future. Debris removal activities described in this NOC will supersede the previously approved NOC (DOE/RL-95-65). The proposed modifications described are scheduled to begin in calendar year 1997.

  4. Toluene removal from waste air stream by the catalytic ozonation process with MgO/GAC composite as catalyst.

    PubMed

    Rezaei, Fatemeh; Moussavi, Gholamreza; Bakhtiari, Alireza Riyahi; Yamini, Yadollah

    2016-04-01

    This paper investigates the catalytic potential of MgO/GAC composite for toluene elimination from waste air in the catalytic ozonation process (COP). The MgO/GAC composite was a micro-porous material with the BET surface area of 1082m(2)/g. Different functional groups including aromatic CC, saturated CO of anhydrates, hydroxyl groups and SH bond of thiols were identified on the surface of MgO/GAC. Effects of residence time (0.5-4s), inlet toluene concentration (100-400ppmv) and bed temperature (25-100°C) were investigated on degradation of toluene in COP. Impregnation of GAC with MgO increased the breakthrough time and removal capacity by 73.9% and 64.6%, respectively, at the optimal conditions. The catalytic potential of the GAC and MgO/GAC for toluene degradation was 11.1% and 90.6%, respectively, at the optimum condition. The highest removal capacity using MgO/GAC (297.9gtoulene/gMgO/GAC) was attained at 100°C, whereas the highest removal capacity of GAC (128.5mgtoulene/gGAC) was obtained at 25°C. Major by-products of the toluene removal in COP with GAC were Formic acid, benzaldehyde, O-nitro-p-cresol and methyl di-phenyl-methane. MgO/GAC could greatly catalyze the decomposition of toluene in COPand formic acid was the main compound desorbed from the catalyst. Accordingly, the MgO/GAC is an efficient material to catalyze the ozonation of hydrocarbon vapors. PMID:26784452

  5. Combined removal of BTEX in air stream by using mixture of sugar cane bagasse, compost and GAC as biofilter media.

    PubMed

    Mathur, Anil K; Majumder, C B; Chatterjee, Shamba

    2007-09-01

    Biofiltration of air stream containing mixture of benzene, toluene, ethyl benzene and o-xylene (BTEX) has been studied in a lab-scale biofilter packed with a mixture of compost, sugar cane bagasse and granulated activated carbon (GAC) in the ratio 55:30:15 by weight. Microbial acclimation was achieved in 30 days by exposing the system to average BTEX inlet concentration of 0.4194 gm(-3) at an empty bed residence time (EBRT) of 2.3 min. Biofilter achieved maximum removal efficiency more than 99% of all four compounds for throughout its operation at an EBRT of 2.3 min for an inlet concentration of 0.681 gm(-3), which is quite significance than the values reported in the literature. The results indicate that when the influent BTEX loadings were less than 68 gm(-3)h(-1) in the biofilter, nearly 100% removal could be achieved. A maximum elimination capacity (EC) of 83.65 gm(-3)h(-1) of the biofilter was obtained at inlet BTEX load of 126.5 gm(-3)h(-1) in phase IV. Elimination capacities of BTEX increased with the increase in influent VOC loading, but an opposite trend was observed for the removal efficiency. The production of CO(2) in each phase (gm(-3)h(-1)) was also observed at steady state (i.e. at maximum removal efficiency). Moreover, the high concentrations of nitrogen in the nutrient solution may adversely affect the microbial activity possibly due to the presence of high salt concentrations. Furthermore, an attempt was also made to isolate the most profusely grown BTEX-degrading strain. A Gram-positive strain had a high BTEX-degrading activity and was identified as Bacillus sphaericus by taxonomical analysis, biochemical tests and 16S rDNA gene analysis methods.

  6. Analytical model of dual-media biofilter for removal of organic air pollutants

    SciTech Connect

    Abumaizar, R.J.; Smith, E.H.; Kocher, W.

    1997-06-01

    A steady-state mathematical model is presented to describe the kinetics of volatile organic compound (VOC) removal in biofilters that consist of a mixed compost and granular activated carbon (GAC) medium. The model describes the basic transport of VOCs from the gas phase into the liquid phase of the compost biofilm and into the carbon particles, using the assumptions of diffusion as characterized by Fick`s law. The kinetics of biological degradation of substrate (pollutant) in the compost biofilm are assumed to follow a Monod-like relationship. Experimental data were compared with model predictions under steady-state conditions for treatment of a mixture of benzene, toluene, ethylbenzene, and o-xylene (BTEX) vapors. Best results were obtained when model applications were divided according to first-order biodegradation kinetics for relatively low influent concentrations (< 50 ppm) of pollutants and zero-order reaction for higher (235--440 ppm) influent concentrations. In both instances, the model produced suitable approximation of experimental bed depth versus concentration profiles at steady state for individual compounds in biofilters containing small but varying amounts of GAC. The presence of GAC improved BTEX removal efficiencies over a biofilter containing only compost.

  7. Photocatalytic removal of pesticide dichlorvos from indoor air: a study of reaction parameters, intermediates and mineralization.

    PubMed

    Sleiman, Mohamad; Ferronato, Corinne; Chovelon, Jean-Marc

    2008-04-15

    This paper presents for the first time the investigation of TiO2 photocatalysis for the removal of pesticides in gas phase. Dichlorvos was used as a model pesticide, and experiments were carried out using both static and dynamic reaction systems to explore the different aspects of the process. Thus, adsorption, reaction kinetics, and the influence of several operational parameters such as relative humidity (RH), inlet concentration, flow rate, and association of TiO2 with activated carbon (AC) were all examined in detail. Furthermore, a special attention was devoted to the analysis of reaction products by means of various analytical techniques such as Fourier transform infrared spectroscopy, automated thermal desorption technique coupled to gas chromatography-mass spectrometry instrument, gas chromatography equipped with a pulse discharge helium photoionization detector, and ion chromatography. The results showed an immediate and total removal of dichlorvos at ppbv levels (50-350 ppbv) along with a high mineralization extent (50-85%) into harmless final products (CO2, HCl, PO43-). Moreover, RH was found to significantly affectthe mineralization extent and the formation of reaction intermediates. On the basis of identification data, direct charge transfer and chlorine radical (Cl*) attack were shown to play a key role in the reaction mechanism at low RH, whereas at high RH, HO* radicals were the predominant active species.

  8. Characterization of air toxics from a laboratory coal-fired combustor

    SciTech Connect

    1995-04-03

    Emissions of hazardous air pollutants from coal combustion were studied in a laboratory-scale combustion facility, with emphasis on fine particles in three size ranges of less than 7.5 {mu}m diameter. Vapors were also measured. Substances under study included organic compounds, anions, elements, and radionuclides. Fly ash was generated by firing a bituminous coal in a combuster for 40 h at each of two coal feed rates. Flue gas was sampled under two conditions. Results for organic compounds, anions, and elements show a dependence on particle size consistent with published power plant data. Accumulation of material onto surface layers was inferred from differences in chemical composition between the plume simulating dilution sampler and hot flue samples. Extracts of organic particulate material were fractionated into different polarity fractions and analyzed by GC/MS. In Phase II, these laboratory results will be compared to emissions from a full-scale power plant burning the same coal.

  9. Emissions of air toxics from a simulated charcoal kiln. Final report, October 1997--September 1998

    SciTech Connect

    Lemieux, P.M.

    1999-06-01

    The report gives results of experiments in a laboratory-scale charcoal kiln simulator to evaluate emissions of hazardous air pollutants from the production of charcoal in Missouri-type kilns. Fixed combustion gases were measured using continuous monitors. In addition, other pollutants, including methanol, volatile organic compounds, semivolatile organic compounds, and particle emission rates and size distributions were measured using various techniques. Emissions of all pollutants are reported in units of grams emitted per unit mass of initial wood converted to charcoal. Two burn conditions--slow and fast--were examined. High levels of methanol, benzene, and fine particulate were emitted in all tests. The estimated emissions from the fast burn conditions were significantly higher than those from the slow burn conditions.

  10. Emissions of air toxics from the production of charcoal in a simulated Missouri charcoal kiln

    SciTech Connect

    Lemieux, P.M.; Kariher, P.H.; Fairless, B.J.; Tapp, J.A.

    1998-11-01

    The paper gives results of experiments in a laboratory-scale charcoal kiln simulator to evaluate emissions of hazardous air pollutant from the production of charcoal in Missouri-type kilns. Fixed combustion gases were measured using continuous monitors. In addition, other pollutants, including methanol, volatile organic compounds, semivolatile organic compounds, and particle emission rates and size distributions were measured using various techniques. Emissions of all pollutants are reported in grams emitted per unit mass of initial wood converted to charcoal. Two burn conditions--slow and fast burn--were examined. High levels of methanol, benzene, and fine particulate were emitted from all tests. The estimated emissions from the fast burn conditions were significantly higher than those from the slow burn conditions.

  11. Auditing of sampling methods for air toxics at coal-fired power plants

    SciTech Connect

    Agbede, R.O.; Clements, J.L.; Grunebach, M.G.

    1995-11-01

    Advanced Technology Systems, Inc. (ATS) with subcontract assistance from international Technology Corporation (IT) has provided external audit activities for Phase II of the Department of Energy-Pittsburgh Energy Technology Center`s air emission test program. The objective of the audits is to help ensure that the data obtained from the emission tests are precise, accurate, representative, scientifically sound and legally defensible. This paper presents the criteria that were used to perform the external audits of the emission test program. It also describes the approach used by ATS and It in performing their audits. Examples of findings of the audits along with the actions take to correct problems and the subsequent effect of those actions on the test data are presented. The results of audit spikes performed at the Plant 1 test site are also discussed.

  12. Sampling of power plant stacks for air toxic emissions: Topical report for Phases 1 and 2

    SciTech Connect

    1995-02-21

    Under contract with the US Department of Energy (DE-AC22-92PCO0367), Pittsburgh Energy Technology Center, Radian Corporation has conducted a test program to collect and analyze size-fractionated stack gas particulate samples for selected inorganic hazardous air pollutants (HAPS). Specific goals of the program are (1) the collection of one-gram quantities of size-fractionated stack gas particulate matter for bulk (total) and surface chemical charactization, and (2) the determination of the relationship between particle size, bulk and surface (leachable) composition, and unit load. The information obtained from this program identifies the effects of unit load, particle size, and wet FGD system operation on the relative toxicological effects of exposure to particulate emissions.

  13. Experimental Study on Ultrafine Particle Removal Performance of Portable Air Cleaners with Different Filters in an Office Room.

    PubMed

    Ma, Huan; Shen, Henggen; Shui, Tiantian; Li, Qing; Zhou, Liuke

    2016-01-05

    Size- and time-dependent aerodynamic behaviors of indoor particles, including PM1.0, were evaluated in a school office in order to test the performance of air-cleaning devices using different filters. In-situ real-time measurements were taken using an optical particle counter. The filtration characteristics of filter media, including single-pass efficiency, volume and effectiveness, were evaluated and analyzed. The electret filter (EE) medium shows better initial removal efficiency than the high efficiency (HE) medium in the 0.3-3.5 μm particle size range, while under the same face velocity, the filtration resistance of the HE medium is several times higher than that of the EE medium. During service life testing, the efficiency of the EE medium decreased to 60% with a total purifying air flow of 25 × 10⁴ m³/m². The resistance curve rose slightly before the efficiency reached the bottom, and then increased almost exponentially. The single-pass efficiency of portable air cleaner (PAC) with the pre-filter (PR) or the active carbon granule filter (CF) was relatively poor. While PAC with the pre-filter and the high efficiency filter (PR&HE) showed maximum single-pass efficiency for PM1.0 (88.6%), PAC with the HE was the most effective at removing PM1.0. The enhancement of PR with HE and electret filters augmented the single-pass efficiency, but lessened the airflow rate and effectiveness. Combined with PR, the decay constant of large-sized particles could be greater than for PACs without PR. Without regard to the lifetime, the electret filters performed better with respect to resource saving and purification improvement. A most penetrating particle size range (MPPS: 0.4-0.65 μm) exists in both HE and electret filters; the MPPS tends to become larger after HE and electret filters are combined with PR. These results serve to provide a better understanding of the indoor particle removal performance of PACs when combined with different kinds of filters in school

  14. Experimental Study on Ultrafine Particle Removal Performance of Portable Air Cleaners with Different Filters in an Office Room

    PubMed Central

    Ma, Huan; Shen, Henggen; Shui, Tiantian; Li, Qing; Zhou, Liuke

    2016-01-01

    Size- and time-dependent aerodynamic behaviors of indoor particles, including PM1.0, were evaluated in a school office in order to test the performance of air-cleaning devices using different filters. In-situ real-time measurements were taken using an optical particle counter. The filtration characteristics of filter media, including single-pass efficiency, volume and effectiveness, were evaluated and analyzed. The electret filter (EE) medium shows better initial removal efficiency than the high efficiency (HE) medium in the 0.3–3.5 μm particle size range, while under the same face velocity, the filtration resistance of the HE medium is several times higher than that of the EE medium. During service life testing, the efficiency of the EE medium decreased to 60% with a total purifying air flow of 25 × 104 m3/m2. The resistance curve rose slightly before the efficiency reached the bottom, and then increased almost exponentially. The single-pass efficiency of portable air cleaner (PAC) with the pre-filter (PR) or the active carbon granule filter (CF) was relatively poor. While PAC with the pre-filter and the high efficiency filter (PR&HE) showed maximum single-pass efficiency for PM1.0 (88.6%), PAC with the HE was the most effective at removing PM1.0. The enhancement of PR with HE and electret filters augmented the single-pass efficiency, but lessened the airflow rate and effectiveness. Combined with PR, the decay constant of large-sized particles could be greater than for PACs without PR. Without regard to the lifetime, the electret filters performed better with respect to resource saving and purification improvement. A most penetrating particle size range (MPPS: 0.4–0.65 μm) exists in both HE and electret filters; the MPPS tends to become larger after HE and electret filters are combined with PR. These results serve to provide a better understanding of the indoor particle removal performance of PACs when combined with different kinds of filters in school

  15. Experimental Study on Ultrafine Particle Removal Performance of Portable Air Cleaners with Different Filters in an Office Room.

    PubMed

    Ma, Huan; Shen, Henggen; Shui, Tiantian; Li, Qing; Zhou, Liuke

    2016-01-01

    Size- and time-dependent aerodynamic behaviors of indoor particles, including PM1.0, were evaluated in a school office in order to test the performance of air-cleaning devices using different filters. In-situ real-time measurements were taken using an optical particle counter. The filtration characteristics of filter media, including single-pass efficiency, volume and effectiveness, were evaluated and analyzed. The electret filter (EE) medium shows better initial removal efficiency than the high efficiency (HE) medium in the 0.3-3.5 μm particle size range, while under the same face velocity, the filtration resistance of the HE medium is several times higher than that of the EE medium. During service life testing, the efficiency of the EE medium decreased to 60% with a total purifying air flow of 25 × 10⁴ m³/m². The resistance curve rose slightly before the efficiency reached the bottom, and then increased almost exponentially. The single-pass efficiency of portable air cleaner (PAC) with the pre-filter (PR) or the active carbon granule filter (CF) was relatively poor. While PAC with the pre-filter and the high efficiency filter (PR&HE) showed maximum single-pass efficiency for PM1.0 (88.6%), PAC with the HE was the most effective at removing PM1.0. The enhancement of PR with HE and electret filters augmented the single-pass efficiency, but lessened the airflow rate and effectiveness. Combined with PR, the decay constant of large-sized particles could be greater than for PACs without PR. Without regard to the lifetime, the electret filters performed better with respect to resource saving and purification improvement. A most penetrating particle size range (MPPS: 0.4-0.65 μm) exists in both HE and electret filters; the MPPS tends to become larger after HE and electret filters are combined with PR. These results serve to provide a better understanding of the indoor particle removal performance of PACs when combined with different kinds of filters in school

  16. Removal of ammonia from air on molybdenum and tungsten oxide modified activated carbons.

    PubMed

    Petit, Camille; Bandosz, Teresa J

    2008-04-15

    Microporous coconut-based activated carbon was impregnated with solutions of ammonium metatungstate or ammonium molybdate and then calcined in air in order to convert the salts into their corresponding oxides. The surface of those materials was characterized using adsorption of nitrogen, potentiometric titration, Fourier-transform infrared spectroscopy, X-ray diffraction, and thermal analysis. The results indicated a significant increase in surface acidity related to the presence of tungsten or molybdenum oxides. On the materials obtained, adsorption of ammonia from either dry or moist air was carried out. The oxides distributed on the surface provided Lewis and/or Brønsted centers for interactions with ammonia molecules or ammonium ions. Water on the surface of carbon or in the gas phase increased the amount of ammonia adsorbed via involvement of Brønsted-type interactions and/or by leading to the formation of molybdate or tungstate salts on the surface. Although the amount of ammonia adsorbed is closely related to the number of moles of oxides and their acidic centers, the carbon surface also contributes to the adsorption via providing small pores where ammonia can be dissolved in the water film.

  17. CHANGES IN LUNG FUNCTION OBSERVED IN A STUDY OF PM AND AIR TOXICS EXPOSURE TO NC HIGHWAY PATROL TROOPERS (COPP-STUDY)

    EPA Science Inventory

    Introduction: Car emissions have been identified as a major source of respirable particles. Individuals whose jobs involve being on the road, such as patrol troopers, may be exposed to high cencentrations of toxic air pollutants from vehicle emissions. This exposure might a...

  18. REAL TIME, ON-LINE CHARACTERIZATION OF DIESEL GENERATOR AIR TOXIC EMISSIONS BY RESONANCE ENHANCED MULTI-PHOTON IONIZATION TIME OF FLIGHT MASS SPECTROMETRY

    EPA Science Inventory

    The laser based resonance, enhanced multi-photon ionization time-of-flight mass spectrometry (REMPI-TOFMS) technique has been applied to the exhaust gas stream of a diesel generator to measure, in real time, concentration levels of aromatic air toxics. Volatile organic compounds ...

  19. REAL-TIME EMISSION CHARACTERIZATION OF ORGANIC AIR TOXIC POLLUTANTS DURING STEADY STATE AND TRANSIENT OPERATION OF A MEDIUM DUTY DIESEL ENGINE

    EPA Science Inventory

    An on-line monitoring method, jet resonance-enhanced multi-photon ionization (REMPI) with time-of-flight mass spectrometry (TOFMS) was used to measure emissions of organic air toxics from a medium-duty (60 kW)diesel generator during transient and steady state operations. Emission...

  20. Removing a small quantity of THT from gas storage groundwater through air stripping and gas-phase carbon adsorption

    SciTech Connect

    Girod, J.F.; Leclerc, J.P.; Muhr, H.

    1996-12-31

    This paper deals with the response to a case of contaminated groundwater located in France. The natural gas is stored during summer in porous underground rocks. When energy requirements increase (particularly in winter), gas is drawn off, but water is also pumped during this operation. The water has a strong characteristic odour of the TetraHydroThiophene (THT), which has been used by Gaz de France as an additive in order to detect gas leakages because of its strong odour. Unfortunately, the presence of THT in medium other than natural gas can be responsible for safety problems. Gas stripping combined with adsorption on granular activated carbon was chosen to obtain removal of THT from the groundwater. The gas to water ratio for stripping column is higher than usual and the gas used for stripping was recycled in order to prevent air pollution. Carbon consumption is approximately 3 tons a year. 8 refs., 5 figs., 2 tabs.

  1. Sampling of power plant stacks for air toxic emissions: Final report for Phases 1 and 2

    SciTech Connect

    1995-04-28

    A test program to collect and analyze size-fractionated stack gas particulate samples for selected inorganic hazardous air pollutants (HAPs) was conducted . Specific goals of the program are (1) the collection of one-gram quantities of size-fractionated stack gas particulate matter for bulk (total) and surface chemical characterization, and (2) the determination of the relationship between particle size, bulk and surface (leachable) composition, and unit load. The information obtained from this program identifies the effects of unit load, particle size, and wet FGD system operation on the relative toxicological effects of exposure to particulate emissions. Field testing was conducted in two phases. The Phase I field program was performed over the period of August 24 through September 20, 1992, at the Tennessee Valley Authority Widows Creek Unit 8 Power Station, located near Stevenson (Jackson County), Alabama, on the Tennessee River. Sampling activities for Phase II were conducted from September 11 through October 14, 1993. Widows Creek Unit 8 is a 575-megawatt plant that uses bituminous coal averaging 3.7% sulfur and 13% ash. Downstream of the boiler, a venture wet scrubbing system is used for control of both sulfur dioxide and particulate emissions. There is no electrostatic precipitator (ESP) in this system. This system is atypical and represents only about 5% of the US utility industry. However, this site was chosen for this study because of the lack of information available for this particulate emission control system.

  2. Notice of Construction (NOC) Application for Criteria and Toxic Air Pollutant Emissions from Thermal Stabilization of Polycubes at the PFP

    SciTech Connect

    RANADE, D.G.

    2000-11-01

    This is a notice of construction (NOC) application for thermal stabilization of plutonium in a polystyrene matrix (polycubes) in the muffle furnaces at the Plutonium Finishing Plant (PFP). This NOC application is required by Washington Administrative Code (WAC) 173-460-040. During the 1960's and 1970's, polycubes were thermally stabilized using a pyrolysis process at PFP. The proposed process of thermal stabilization of polycubes in muffle furnaces results in emissions of air contaminants not emitted since implementation of WAC 173-460 (effective 9/18/91). The new process and related air contaminants are the basis for this NOC application. The proposed activity would use the muffle furnaces in the 234-52 Building to stabilize polycubes. The resulting plutonium oxides would be packaged to meet storage requirements specified in Stabilization, Packaging, and Storage of Plutonium Bearing Materials (DOE-STD-3013). The PFP is located in the 200 West Area of the Hanford Site. The PFP consists of several large and small buildings that are grouped to form the processing complex. The PFP activities are focused on the stabilization of plutonium-bearing materials to a form suitable for long-term storage; immobilization of residual plutonium-bearing materials; and removal of readily retrievable, plutonium-bearing materials left behind in process equipment and process areas.

  3. A Fine-Tuned Fluorinated MOF Addresses the Needs for Trace CO2 Removal and Air Capture Using Physisorption.

    PubMed

    Bhatt, Prashant M; Belmabkhout, Youssef; Cadiau, Amandine; Adil, Karim; Shekhah, Osama; Shkurenko, Aleksander; Barbour, Leonard J; Eddaoudi, Mohamed

    2016-07-27

    The development of functional solid-state materials for carbon capture at low carbon dioxide (CO2) concentrations, namely, from confined spaces (<0.5%) and in particular from air (400 ppm), is of prime importance with respect to energy and environment sustainability. Herein, we report the deliberate construction of a hydrolytically stable fluorinated metal-organic framework (MOF), NbOFFIVE-1-Ni, with the appropriate pore system (size, shape, and functionality), ideal for the effective and energy-efficient removal of trace carbon dioxide. Markedly, the CO2-selective NbOFFIVE-1-Ni exhibits the highest CO2 gravimetric and volumetric uptake (ca. 1.3 mmol/g and 51.4 cm(3) (STP) cm(-3)) for a physical adsorbent at 400 ppm of CO2 and 298 K. Practically, NbOFFIVE-1-Ni offers the complete CO2 desorption at 328 K under vacuum with an associated moderate energy input of 54 kJ/mol, typical for the full CO2 desorption in conventional physical adsorbents but considerably lower than chemical sorbents. Noticeably, the contracted square-like channels, affording the close proximity of the fluorine centers, permitted the enhancement of the CO2-framework interactions and subsequently the attainment of an unprecedented CO2 selectivity at very low CO2 concentrations. The precise localization of the adsorbed CO2 at the vicinity of the periodically aligned fluorine centers, promoting the selective adsorption of CO2, is evidenced by the single-crystal X-ray diffraction study on NbOFFIVE-1-Ni hosting CO2 molecules. Cyclic CO2/N2 mixed-gas column breakthrough experiments under dry and humid conditions corroborate the excellent CO2 selectivity under practical carbon capture conditions. Pertinently, the notable hydrolytic stability positions NbOFFIVE-1-Ni as the new benchmark adsorbent for direct air capture and CO2 removal from confined spaces. PMID:27388208

  4. A Fine-Tuned Fluorinated MOF Addresses the Needs for Trace CO2 Removal and Air Capture Using Physisorption.

    PubMed

    Bhatt, Prashant M; Belmabkhout, Youssef; Cadiau, Amandine; Adil, Karim; Shekhah, Osama; Shkurenko, Aleksander; Barbour, Leonard J; Eddaoudi, Mohamed

    2016-07-27

    The development of functional solid-state materials for carbon capture at low carbon dioxide (CO2) concentrations, namely, from confined spaces (<0.5%) and in particular from air (400 ppm), is of prime importance with respect to energy and environment sustainability. Herein, we report the deliberate construction of a hydrolytically stable fluorinated metal-organic framework (MOF), NbOFFIVE-1-Ni, with the appropriate pore system (size, shape, and functionality), ideal for the effective and energy-efficient removal of trace carbon dioxide. Markedly, the CO2-selective NbOFFIVE-1-Ni exhibits the highest CO2 gravimetric and volumetric uptake (ca. 1.3 mmol/g and 51.4 cm(3) (STP) cm(-3)) for a physical adsorbent at 400 ppm of CO2 and 298 K. Practically, NbOFFIVE-1-Ni offers the complete CO2 desorption at 328 K under vacuum with an associated moderate energy input of 54 kJ/mol, typical for the full CO2 desorption in conventional physical adsorbents but considerably lower than chemical sorbents. Noticeably, the contracted square-like channels, affording the close proximity of the fluorine centers, permitted the enhancement of the CO2-framework interactions and subsequently the attainment of an unprecedented CO2 selectivity at very low CO2 concentrations. The precise localization of the adsorbed CO2 at the vicinity of the periodically aligned fluorine centers, promoting the selective adsorption of CO2, is evidenced by the single-crystal X-ray diffraction study on NbOFFIVE-1-Ni hosting CO2 molecules. Cyclic CO2/N2 mixed-gas column breakthrough experiments under dry and humid conditions corroborate the excellent CO2 selectivity under practical carbon capture conditions. Pertinently, the notable hydrolytic stability positions NbOFFIVE-1-Ni as the new benchmark adsorbent for direct air capture and CO2 removal from confined spaces.

  5. Integrated membrane systems incorporating coagulation, activated carbon and ultrafiltration for the removal of toxic cyanobacterial metabolites from Anabaena circinalis.

    PubMed

    Dixon, M B; Richard, Y; Ho, L; Chow, C W K; O'Neill, B K; Newcombe, G

    2011-01-01

    The use of integrated membrane systems (a train of treatment processes incorporating one or more membranes) is increasing globally as the technology is very effective for the production of high quality drinking water. In this investigation a laboratory scale integrated membrane system (IMS) featuring coagulation, powdered activated carbon (PAC) and ultrafiltration (UF) was investigated for the removal of an Australian strain of the cyanobacteria Anabaena circinalis and the cyanotoxin it produced. Three coagulants were compared, aluminium chlorohydrate (ACH), aluminium sulphate (alum) and an engineered aluminium coagulant referred to as high performance aluminium chlorohydrate (HPAC). PAC (Acticarb PS1000) was tested to determine adsorption of extracellular saxitoxin. Removal of A. circinalis cells was 100% by UF alone and the removal of cells prior to the membrane by coagulation reduced fouling attributed to algogenic organic material. Alum was the least efficient coagulant for removal of cells while ACH and HPAC were similar. Saxitoxin removal reached a maximum of 80% using ACH and PAC. The UF-IMS was challenged using a natural bloom of A. circinalis that occurred in the Myponga Reservoir in South Australia. PMID:21508543

  6. Reducing prospective memory error and costs in simulated air traffic control: External aids, extending practice, and removing perceived memory requirements.

    PubMed

    Loft, Shayne; Chapman, Melissa; Smith, Rebekah E

    2016-09-01

    In air traffic control (ATC), forgetting to perform deferred actions-prospective memory (PM) errors-can have severe consequences. PM demands can also interfere with ongoing tasks (costs). We examined the extent to which PM errors and costs were reduced in simulated ATC by providing extended practice, or by providing external aids combined with extended practice, or by providing external aids combined with instructions that removed perceived memory requirements. Participants accepted/handed-off aircraft and detected conflicts. For the PM task, participants were required to substitute alternative actions for routine actions when accepting aircraft. In Experiment 1, when no aids were provided, PM errors and costs were not reduced by practice. When aids were provided, costs observed early in practice were eliminated with practice, but residual PM errors remained. Experiment 2 provided more limited practice with aids, but instructions that did not frame the PM task as a "memory" task led to high PM accuracy without costs. Attention-allocation policies that participants set based on expected PM demands were modified as individuals were increasingly exposed to reliable aids, or were given instructions that removed perceived memory requirements. These findings have implications for the design of aids for individuals who monitor multi-item dynamic displays. (PsycINFO Database Record PMID:27608067

  7. Toxicity and removal efficiency of pharmaceutical metabolite clofibric acid by Typha spp.--potential use for phytoremediation?

    PubMed

    Dordio, Ana V; Duarte, Cátia; Barreiros, Margarida; Carvalho, A J Palace; Pinto, A P; da Costa, Cristina Teixeira

    2009-02-01

    A study was conducted to assess Typha spp.'s ability to withstand and remove, from water, a metabolite of blood lipid regulator drugs, clofibric acid (CA). At a concentration of 20 microg L(-1), Typha had removed >50% of CA within the first 48h, reaching a maximum of 80% by the end of the assay. Experimental conditions assured that photodegradation, adsorption to vessel walls and microbial degradation did not contribute to the removal. Exposure to higher CA concentrations did not affect Typha's photosynthetic pigments but the overall increase in enzyme activity (ascorbate and guaiacol peroxidases, catalase, superoxide dismutase) indicates that both roots and leaves were affected by the xenobiotic. Eventually, Typha seemed able to cope with the CA's induced oxidative damage suggesting its ability for phytoremediation of CA contaminated waters.

  8. Radioactive air emissions notice of construction debris removal 105-KE basin

    SciTech Connect

    HAYS, C.B.

    1999-10-06

    The 105-KE Basin contains 1,150 Metric Tonnes of Uranium (MTU) of N Reactor fuel, along with less than half a MTU of single pass reactor (SPR) fuel. In addition to the spent nuclear fuel (SNF) in the 105-KE Basin, extensive quantities of debris and a substantial amount of sludge have accumulated in the basin. The 105-KE Basin fuel and sludge are not encapsulated and, as a result, corroding fuel has produced contamination products that are deposited on the basin walls, floor, and equipment. contamination products produce radiation dose exposures to the workers. To decrease worker exposures, this Notice of Construction (NOC) describes dose reduction modifications under consideration to mitigate worker radiation exposure from the basin walls and exposed piping. The major equipment egress paths from the basin (the dummy elevator pit and the south loadout pit) are blocked completely with debris and/or empty canisters. Therefore in addition to dose reduction, this NOC also describes debris removal activities and equipment. Recently, the primary water treatment system has been without mechanical filtration capabilities. This NOC describes planned modifications to the primary water treatment system to restore mechanical filtration by restarting the cartridge filters. The proposed modifications described in this NOC are expected to commence in the Fall of 1995. Finally, the NOC describes two other basin activities, fuel and sludge movement, that are expected to be routine in the future.

  9. “Large Animal Model of Pumpless Arteriovenous Extracorporeal CO2 Removal Using Room Air Via Subclavian Vessels”

    PubMed Central

    Witer, Lucas; Howard, Ryan; Trahanas, John; Bryner, Benjamin S.; Alghanem, Fares; Hoffman, Hayley R.; Cornell, Marie S.; Bartlett, Robert H.; Rojas-Peña, Alvaro

    2016-01-01

    End-stage lung disease (ESLD) causes progressive hypercapnia, dyspnea, and impacts quality of life. Many extracorporeal support (ECS) configurations for CO2 removal resolve symptoms but limit ambulation. An ovine model of pumpless ECS using subclavian vessels was developed to allow for ambulatory support. Vascular grafts were anastomosed to the left subclavian vessels in four healthy sheep. A low-resistance membrane oxygenator was attached in an arteriovenous (AV) configuration. Device function was evaluated in each animal while awake and spontaneously breathing, and while mechanically ventilated with hypercapnia induced. Sweep gas (FiO2=0.21) to the device was increased from 0-15 L/min and arterial and post-device blood gases, as well as post-device air, were sampled. Hemodynamics remained stable with average AV shunt flows of 1.34±0.14 L/min.. In awake animals, CO2 removal was 3.4±1.0 mL/kg/min at maximum sweep gas flow. Respiratory rate decreased from 60±25 at baseline to 30±11 breaths per minute. In animals with induced hypercapnia, PaCO2 increased to 73.9±15.1. At maximum sweep gas flow, CO2 removal was 3.4±0.4 mL/kg/min and PaCO2 decreased to 49.1±6.7 mmHg. Subclavian AV access is effective in lowering PaCO2 and respiratory rate, and is potentially an effective ambulatory destination therapy for ESLD patients. PMID:26461241

  10. Tricrystalline TiO2 with enhanced photocatalytic activity and durability for removing volatile organic compounds from indoor air.

    PubMed

    Chen, Kunyang; Zhu, Lizhong; Yang, Kun

    2015-06-01

    It is important to develop efficient and economic techniques for removing volatile organic compounds (VOCs) in indoor air. Heterogeneous TiO2-based semiconductors are a promising technology for achieving this goal. Anatase/brookite/rutile tricrystalline TiO2 with mesoporous structure was synthesized by a low-temperature hydrothermal route in the presence of HNO3. The obtained samples were characterized by X-ray diffraction and N2 adsorption-desorption isotherm. The photocatalytic activity was evaluated by photocatalytic decomposition of toluene in air under UV light illumination. The results show that tricrystalline TiO2 exhibited higher photocatalytic activity and durability toward gaseous toluene than bicrystalline TiO2, due to the synergistic effects of high surface area, uniform mesoporous structure and junctions among mixed phases. The tricrystalline TiO2 prepared at RHNO3=0.8, containing 80.7% anatase, 15.6% brookite and 3.7% rutile, exhibited the highest photocatalytic activity, about 3.85-fold higher than that of P25. The high activity did not significantly degrade even after five reuse cycles. In conclusion, it is expected that our study regarding gas-phase degradation of toluene over tricrystalline TiO2 will enrich the chemistry of the TiO2-based materials as photocatalysts for environmental remediation and stimulate further research interest on this intriguing topic.

  11. Tricrystalline TiO2 with enhanced photocatalytic activity and durability for removing volatile organic compounds from indoor air.

    PubMed

    Chen, Kunyang; Zhu, Lizhong; Yang, Kun

    2015-06-01

    It is important to develop efficient and economic techniques for removing volatile organic compounds (VOCs) in indoor air. Heterogeneous TiO2-based semiconductors are a promising technology for achieving this goal. Anatase/brookite/rutile tricrystalline TiO2 with mesoporous structure was synthesized by a low-temperature hydrothermal route in the presence of HNO3. The obtained samples were characterized by X-ray diffraction and N2 adsorption-desorption isotherm. The photocatalytic activity was evaluated by photocatalytic decomposition of toluene in air under UV light illumination. The results show that tricrystalline TiO2 exhibited higher photocatalytic activity and durability toward gaseous toluene than bicrystalline TiO2, due to the synergistic effects of high surface area, uniform mesoporous structure and junctions among mixed phases. The tricrystalline TiO2 prepared at RHNO3=0.8, containing 80.7% anatase, 15.6% brookite and 3.7% rutile, exhibited the highest photocatalytic activity, about 3.85-fold higher than that of P25. The high activity did not significantly degrade even after five reuse cycles. In conclusion, it is expected that our study regarding gas-phase degradation of toluene over tricrystalline TiO2 will enrich the chemistry of the TiO2-based materials as photocatalysts for environmental remediation and stimulate further research interest on this intriguing topic. PMID:26040745

  12. Removal of volatile organic compounds from groundwater using a rotary air stripper

    SciTech Connect

    Singh, S.P. ); Wilson, J.H.; Counce, R.M.; Villiers-Fisher, J.F.; Jennings, H.L. . Chemical Technology Div.); Lucero, A.J.; Reed, G.D. . Dept. of Chemical Engineering); Ashworth, R.A.; Elliott, M.G. )

    1992-02-01

    In this paper, the performance of a centrifugal vapor-liquid contactor is evaluated for air stripping of jet fuel components from ground water. Hydraulic test data indicated that the Sherwood flooding correlation, which has been proposed for use in designing centrifugal vapor-liquid contactors, overestimates the rotational speeds at which flooding occurs. A concept of the area of a transfer unit (ATU) was introduced in the mass-transfer tests to account for the change in fluid loading with the radius of the packing torus. A new correlation based on the specific surface area of the packing for predicting ATU described the experimental data with a fair degree of accuracy. The power consumed in rotating the packing torus was found to depend mainly on the liquid flow, outer rotor radius, and rotational speed. Previous claims in the literature that the centrifugal vapor-liquid contactor is resistant to fouling because of high shear forces were not found to be valid for groundwater with high iron content.

  13. Chemical kinetics with electrical and gas dynamics modelization for NOx removal in an air corona discharge

    NASA Astrophysics Data System (ADS)

    Eichwald, O.; Guntoro, N. A.; Yousfi, M.; Benhenni, M.

    2002-03-01

    A non-stationary reactive gas dynamics model in a mono-dimensional geometry, including radial mass diffusion, gas temperature variation and chemical kinetics, is developed in this paper. The aim is to analyse the spatio-temporal evolution of the main neutral species involved in a corona discharge used for NO pollution control in polluted air at atmospheric pressure and ambient temperature. The present reactive gas dynamics model takes into account 16 neutral chemical species (including certain metastable species) reacting following 110 selected chemical reactions. The initial concentration of each neutral species is obtained from a 1.5D electrical discharge model. The gas temperature variations are due to direct Joule heating during the discharge phase, and also result from the delayed heating due to the relaxation of the vibrational energy into a random thermal energy during the post-discharge phase. The simulation conditions are those of an existing experimental setup (anode voltage of 10 kV in the case of a point to plane geometry with an interelectrode distance of 10 mm). The obtained results show that the diffusion phenomena and the gas temperature rise affect quite well the gas reactivity and the neutral species evolution. This allows us to better understand the different reaction processes and transport phenomena affecting the NO concentration magnitude inside the discharge channel.

  14. An environmentally friendly method to remove and utilize the highly toxic strychnine in other products based on proton-transfer complexation

    NASA Astrophysics Data System (ADS)

    Adam, Abdel Majid A.; Refat, Moamen S.; Saad, Hosam A.; Hegab, Mohamed S.

    2015-12-01

    The study of toxic and carcinogenic substances represents one of the most demanding areas in human safety, due to their repercussions for public health. There is great motivation to remove and utilize these substances in other products instead of leaving them contaminate the environment. One potentially toxic compound for humans is strychnine (Sy). In the present study, we attempted to establish a quick, simple, direct and efficient method to remove and utilize discarded Sy in other products based on proton-transfer complexation. First, Sy was reacted with the acido organic acceptors PA, DNBA and CLA. Then, the resultant salts were direct carbonized into carbon materials. Also, this study provides an insight into the structure and morphology of the obtained products by a range of physicochemical techniques, such as UV-visible, IR, 1H NMR and 13C NMR spectroscopies; XRD; SEM; TEM; and elemental and thermal analyses. Interestingly, the complexation of Sy with the PA or DNBA acceptor leads to a porous carbon material, while its complexation with CLA acceptor forms non-porous carbon product.

  15. Objective Assessment of an Ionic Footbath (IonCleanse): Testing Its Ability to Remove Potentially Toxic Elements from the Body

    PubMed Central

    Kennedy, Deborah A.; Cooley, Kieran; Einarson, Thomas R.; Seely, Dugald

    2012-01-01

    Ionic footbaths are often used in holistic health centres and spas to aid in detoxification; however, claims that these machines eliminate toxins from the body have not been rigorously evaluated. In this proof-of-principle study, we sought to measure the release of potentially toxic elements from ionic footbaths into distilled and tap water with and without feet. Water samples were collected and analyzed following 30-minute ionic footbath sessions without feet using both distilled (n = 1) and tap water (n = 6) and following four ionic footbaths using tap water (once/week for 4 weeks) in six healthy participants. Urine collection samples were analyzed at four points during the study. Hair samples were analyzed for element concentrations at baseline and study conclusion. Contrary to claims made for the machine, there does not appear to be any specific induction of toxic element release through the feet when running the machine according to specifications. PMID:22174728

  16. Objective assessment of an ionic footbath (IonCleanse): testing its ability to remove potentially toxic elements from the body.

    PubMed

    Kennedy, Deborah A; Cooley, Kieran; Einarson, Thomas R; Seely, Dugald

    2012-01-01

    Ionic footbaths are often used in holistic health centres and spas to aid in detoxification; however, claims that these machines eliminate toxins from the body have not been rigorously evaluated. In this proof-of-principle study, we sought to measure the release of potentially toxic elements from ionic footbaths into distilled and tap water with and without feet. Water samples were collected and analyzed following 30-minute ionic footbath sessions without feet using both distilled (n = 1) and tap water (n = 6) and following four ionic footbaths using tap water (once/week for 4 weeks) in six healthy participants. Urine collection samples were analyzed at four points during the study. Hair samples were analyzed for element concentrations at baseline and study conclusion. Contrary to claims made for the machine, there does not appear to be any specific induction of toxic element release through the feet when running the machine according to specifications. PMID:22174728

  17. Development of a Next-Generation Membrane-Integrated Adsorption Processor for CO2 Removal and Compression for Closed-Loop Air Revitalization Systems

    NASA Technical Reports Server (NTRS)

    Mulloth, Lila; LeVan, Douglas

    2002-01-01

    The current CO2 removal technology of NASA is very energy intensive and contains many non-optimized subsystems. This paper discusses the concept of a next-generation, membrane integrated, adsorption processor for CO2 removal nd compression in closed-loop air revitalization systems. This processor will use many times less power than NASA's current CO2 removal technology and will be capable of maintaining a lower CO2 concentration in the cabin than that can be achieved by the existing CO2 removal systems. The compact, consolidated, configuration of gas dryer, CO2 separator, and CO2 compressor will allow continuous recycling of humid air in the cabin and supply of compressed CO2 to the reduction unit for oxygen recovery. The device has potential application to the International Space Station and future, long duration, transit, and planetary missions.

  18. Air toxics and epigenetic effects: ozone altered microRNAs in the sputum of human subjects

    PubMed Central

    Fry, Rebecca C.; Rager, Julia E.; Bauer, Rebecca; Sebastian, Elizabeth; Peden, David B.; Jaspers, Ilona

    2014-01-01

    Ozone (O3) is a criteria air pollutant that is associated with numerous adverse health effects, including altered respiratory immune responses. Despite its deleterious health effects, possible epigenetic mechanisms underlying O3-induced health effects remain understudied. MicroRNAs (miRNAs) are epigenetic regulators of genomic response to environmental insults and unstudied in relationship to O3 inhalation exposure. Our objective was to test whether O3 inhalation exposure significantly alters miRNA expression profiles within the human bronchial airways. Twenty healthy adult human volunteers were exposed to 0.4 ppm O3 for 2 h. Induced sputum samples were collected from each subject 48 h preexposure and 6 h postexposure for evaluation of miRNA expression and markers of inflammation in the airways. Genomewide miRNA expression profiles were evaluated by microarray analysis, and in silico predicted mRNA targets of the O3-responsive miRNAs were identified and validated against previously measured O3-induced changes in mRNA targets. Biological network analysis was performed on the O3-associated miRNAs and mRNA targets to reveal potential associated response signaling and functional enrichment. Expression analysis of the sputum samples revealed that O3 exposure significantly increased the expression levels of 10 miRNAs, namely miR-132, miR-143, miR-145, miR-199a*, miR-199b-5p, miR-222, miR-223, miR-25, miR-424, and miR-582-5p. The miRNAs and their predicted targets were associated with a diverse range of biological functions and disease signatures, noted among them inflammation and immune-related disease. The present study shows that O3 inhalation exposure disrupts select miRNA expression profiles that are associated with inflammatory and immune response signaling. These findings provide novel insight into epigenetic regulation of responses to O3 exposure. PMID:24771714

  19. Radioactive air emissions notice of construction fuel removal for 105-KW Basin

    SciTech Connect

    Hays, C.B.

    1997-05-29

    This document serves as a Notice of Construction (NOC), pursuant to the requirements of Washington Administrative Code (WAC) 246-247-060, and as a request for approval to construct, pursuant to 40 Code of Federal Regulations (CFR) 61.96, for the modifications, installation of new equipment, and fuel removal and sludge relocation activities at 105-KW Basin. The purpose of the activities described in this NOC is to enable the eventual retrieval and transport of the fuel for processing. The fuel retrieval and transport will require an integrated water treatment system for which performance specifications have been developed. These specifications are currently in the procurement process. Following procurement (and before installation of this system and the handling of fuel) design details will be provided to Washington State Department of Health (WDOH). The 105-K West Reactor (105-KW) and its associated spent nuclear fuel (SNF) storage basin were constructed in the early 1950s and are located on the Hanford Site in the 100-K Area about 1,400 feet from the Columbia River. The 105-KW Basin contains 964 Metric Tons of SNF stored under water in approximately 3,800 closed canisters. This SNF has been stored for varying periods of time ranging from 8 to 17 years. The 105-KW Basin is constructed of concrete with an epoxy coating and contains approximately 1.3 million gallons of water with an asphaltic membrane beneath the pool. Although the 105-KW Basin has not been known to leak, the discharge chute and associated construction joint have been isolated from the rest of the basin by metal isolation barriers. This was a precautionary measure, to mitigate the consequences of a seismic event. The proposed modifications described are scheduled to begin in calendar year 1997.

  20. Snow removal and ambient air temperature effects on forest soil temperatures in northern Vermont

    NASA Astrophysics Data System (ADS)

    Wang, D.; Decker, K. L.; Waite, C.; Scherbatskoy, T.

    2003-12-01

    We measured deciduous forest soil temperatures under control (unmanipulated) and snow-free (where snow is manually removed) conditions for four winters (at three soil depths) to determine effects of a snow cover reduction such as may occur as a result of climate change on Vermont forest soils. The four winters we studied were characterized as:`cold and snowy', `warm with low snow', `cold with low snow', and `cool with low snow'. Snow-free soils were colder than controls at 5 and 15 cm depth for all years, and at all depths in the two cold winters. Soil thermal variability generally decreased with both increased snow cover and soil depth. The effect of snow cover on soil freeze-thaw events was highly dependent on both the depth of snow and the soil temperature. Snow kept the soil warm and reduced soil temperature variability, but often this caused soil to remain near 0 deg C, resulting in more freeze-thaw events under snow at one or more soil depths. During the `cold snowy' winter, soils under snow had daily averages consistently >0 deg C, whereas snow-free soil temperatures commonly dropped below -3 deg C. During the `warm' year, temperatures of soil under snow were often lower than those of snow-free soils. The warmer winter resulted in less snow cover to insulate soil from freezing in the biologically active top 30 cm. The possible consequences of increased soil freezing include more root mortality and nutrient loss which would potentially alter ecosystem dynamics, decrease productivity of some tree species, and increase sugar maple mortality in northern hardwood forests.

  1. Real-Time Cell-Electronic Sensing of Coal Fly Ash Particulate Matter for Toxicity-Based Air Quality Monitoring.

    PubMed

    Moe, Birget; Yuan, Chungang; Li, Jinhua; Du, Haiying; Gabos, Stephan; Le, X Chris; Li, Xing-Fang

    2016-06-20

    The development of a unique bioassay for cytotoxicity analysis of coal fly ash (CFA) particulate matter (PM) and its potential application for air quality monitoring is described. Using human cell lines, A549 and SK-MES-1, as live probes on microelectrode-embedded 96-well sensors, impedance changes over time are measured as cells are treated with varying concentrations (1 μg/mL-20 mg/mL) of CFA samples. A dose-dependent impedance change is determined for each CFA sample, from which an IC50 histogram is obtained. The assay was successfully applied to examine CFA samples collected from three coal-fired power plants (CFPs) in China. The samples were separated into three size fractions: PM2.5 (<2.5 μm), PM10-2.5 (2.5 μm < x < 10 μm), and PM10 (>10 μm). Dynamic cell-response profiles and temporal IC50 histograms of all samples show that CFA cytotoxicity depends on concentration, exposure time (0-60 h), and cell-type (SK-MES-1 > A549). The IC50 values differentiate the cytotoxicity of CFA samples based on size fraction (PM2.5 ≈ PM10-2.5 ≫ PM10) and the sampling location (CFP2 > CFP1 ≈ CFP3). Differential cytotoxicity measurements of particulates in human cell lines using cell-electronic sensing provide a useful tool for toxicity-based air quality monitoring and risk assessment. PMID:27124590

  2. Development of a Prototype Algal Reactor for Removing CO2 from Cabin Air

    NASA Technical Reports Server (NTRS)

    Patel, Vrajen; Monje, Oscar

    2013-01-01

    Controlling carbon dioxide in spacecraft cabin air may be accomplished using algal photobioreactors (PBRs). The purpose of this project was to evaluate the use of a commercial microcontroller, the Arduino Mega 2560, for measuring key photioreactor variables: dissolved oxygen, pH, temperature, light, and carbon dioxide. The Arduino platform is an opensource physical computing platform composed of a compact microcontroller board and a C++/C computer language (Arduino 1.0.5). The functionality of the Arduino platform can be expanded by the use of numerous add-ons or 'shields'. The Arduino Mega 2560 was equipped with the following shields: datalogger, BNC shield for reading pH sensor, a Mega Moto shield for controlling CO2 addition, as well as multiple sensors. The dissolved oxygen (DO) probe was calibrated using a nitrogen bubbling technique and the pH probe was calibrated via an Omega pH simulator. The PBR was constructed using a 2 L beaker, a 66 L box for addition of CO2, a micro porous membrane, a diaphragm pump, four 25 watt light bulbs, a MasterFiex speed controller, and a fan. The algae (wild type Synechocystis PCC6803) was grown in an aerated flask until the algae was dense enough to used in the main reactor. After the algae was grown, it was transferred to the 2 L beaker where CO2 consumption and O2 production was measured using the microcontroller sensor suite. The data was recorded via the datalogger and transferred to a computer for analysis.

  3. Simultaneous removal of ammonia, P and COD from anaerobically digested piggery wastewater using an integrated process of chemical precipitation and air stripping.

    PubMed

    Quan, Xuejun; Ye, Changying; Xiong, Yanqi; Xiang, Jinxin; Wang, Fuping

    2010-06-15

    The paper presented an efficient integrated physicochemical process, which consists of chemical precipitation and air stripping, for the simultaneous removal of NH(3)-N, total P and COD from anaerobically digested piggery wastewater. In the integrated process, Ca(OH) (2) was used as the precipitant for NH(4)(+), PO(4)(3-) and organic phosphorous compounds, and as the pH adjuster for the air stripping of residual ammonia. The possibility of the suggested process and the related mechanisms were first investigated through a series of equilibrium tests. Laboratory scale tests were carried out to validate the application possibility of the integrated process using a new-patented water sparged aerocyclone reactor (WSA). The WSA could be effectively used for the simultaneous removal of NH(3)-N, total P and COD. 3g/L of Ca(OH) (2) is a proper dosage for the simultaneous removal. The simultaneous removal of NH(3)-N, total P and COD in the WSA reactor could be easily optimized by selecting a proper air inlet velocity and a proper jet velocity of the liquid phase. In all the cases, the removal efficiencies of the NH(3)-N, total P and COD were over 91%, 99.2% and 52% for NH(3)-N, total P and COD, respectively. The formed precipitates in the process could be easily settled down from the suspension system. Therefore, the integrated process provided an efficient alternative for the simultaneous removal of NH(3)-N, total P and COD from the wastewater.

  4. New Hydrophilic, Composite Membranes for Air Removal from Water Coolant Systems

    NASA Technical Reports Server (NTRS)

    Ritchie, Stephen M. C.; Luo, Qiang; Curtis, Salina S.; Holladay, Jon B.; Clark, Dallas W.

    2004-01-01

    Liquid coolants are commonly used as thermal transport media to increase efficiency and flexibility in aerospace vehicle design. The introduction of gas bubbles into the coolant can have negative consequences, including: loss of centrifugal pump prime, irregular sensor readings, and blockage of coolant flow to remote systems. One solution to mitigate these problems is the development of a passive gas removal device, or gas trap, installed in the flight cooling system. In this study, a new hydrophilic, composite membrane has been developed for passage of the coolant fluid and retention of gas bubbles. The trapped bubbles are subsequently vented from the system by a thin, hydrophobic, microporous membrane. The original design for this work employed a homogeneous membrane that was susceptible to fouling and pore plugging. Spare gas traps of this variety have degraded during storage, and recreation of the membranes has been complicated due to problems with polymer duplication and property variations in the final membranes. In this work, replacements have been developed based on deposition of a hydrophilic polymer on the bore-side of a porous polyethylene (PE) tube. The tube provides excellent chemical and mechanical stability, and the hydrophilic layer provides retention of gas bubbles. Preliminary results have shown that intimate contact is required between the deposited layer and the substrate to overcome material differences. This has been accomplished by presoaking the membrane tube in the solvent to raise its surface energy. Polymer solutions of various concentrations have been used to promote penetration of the polymer layer into the porous substrate and to control separation layer thickness. The resulting composite membranes have shown repeatable decrease in nitrogen permeability, which is indicative of a decrease in membrane pore size. Studies with water permeation have yielded similar results. We have observed some swelling of the added polymer layer, which

  5. New toxics, new poverty: a social understanding of the freebase cocaine/Paco in Buenos Aires, Argentina.

    PubMed

    Epele, María E

    2011-01-01

    Included within the field of research on changes in drug use patterns and vulnerability are conditions of emergency related to economic crisis, wars, and political conflict. This study addresses the complex connections between the rapid propagation of freebase cocaine (FBC)-locally known as "pasta base" or "Paco" in Argentina and the normalization of the consequences of Argentina's 2001-2002 political-economic crisis. On the basis of the results of an ethnographic study carried out in three neighborhoods of the Greater Buenos Aires area between 2001 and 2005, this article aims to analyze how changes in the material and social living conditions are interrelated with the high toxicity of FBC/Paco and engender the emerging compulsion of its consumption and deterioration to the bodies, subjectivities, and social activities of active drug users from these shantytowns. By analyzing the changes in transactions directly or indirectly involving drugs-specifically those ranging from cocaine to FBC/Paco-we can argue how structural poverty, "new poverty," is not only associated with the expansion of FBC/Paco but is also shaped by its use, modes of consumption, associated health problems, and sufferings.

  6. Between-airport heterogeneity in air toxics emissions associated with individual cancer risk thresholds and population risks

    PubMed Central

    2009-01-01

    Background Airports represent a complex source type of increasing importance contributing to air toxics risks. Comprehensive atmospheric dispersion models are beyond the scope of many applications, so it would be valuable to rapidly but accurately characterize the risk-relevant exposure implications of emissions at an airport. Methods In this study, we apply a high resolution atmospheric dispersion model (AERMOD) to 32 airports across the United States, focusing on benzene, 1,3-butadiene, and benzo [a]pyrene. We estimate the emission rates required at these airports to exceed a 10-6 lifetime cancer risk for the maximally exposed individual (emission thresholds) and estimate the total population risk at these emission rates. Results The emission thresholds vary by two orders of magnitude across airports, with variability predicted by proximity of populations to the airport and mixing height (R2 = 0.74–0.75 across pollutants). At these emission thresholds, the population risk within 50 km of the airport varies by two orders of magnitude across airports, driven by substantial heterogeneity in total population exposure per unit emissions that is related to population density and uncorrelated with emission thresholds. Conclusion Our findings indicate that site characteristics can be used to accurately predict maximum individual risk and total population risk at a given level of emissions, but that optimizing on one endpoint will be non-optimal for the other. PMID:19426510

  7. Evaluation of rotary air stripping for removal of volatile organics from groundwater. Final report, 1 March 1985-1 September 1986

    SciTech Connect

    Dietrich, C.; Treichler, D.; Armstrong, J.

    1987-02-01

    Rotary air stripping was researched and developed to remove volatile organic contaminants from groundwater. The Traverse Group, Inc, Ann Arbor MI, was contracted under a joint funding venture by the US Coast Guard and the US Air Force to evaluate feasibility of using rotary air stripping to treat water contaminated with benzene, toluene, xylenes, trichloroethylene, 1,2,dichloroethane, and tetrachloroethylene. A site of groundwater contamination at the US Coast Guard Station, Traverse City MI provided a readily available source of contaminated water for this work. A prototype rotary air stripper (RAS), manufactured specifically for this project, was installed onsite in Traverse City MI. The RAS (consisting of a packed-bed 1.7 feet in diameter by 1.2 feet thick) was evaluated over a range of contaminant concentrations (63 to 19,000 ppb), liquid flow rates (50 to 120 gpm), air-to-water ratios (10:1 to 170:1 vol/vol), and rotor speeds (365 to 875 rpms). The effect of each parameter on removal efficiency was analyzed. Generally, removal efficiencies in excess of 99 percent were achieved for all contaminants (except 1,2-DCE) at an air-to-water ratio and rotor speed of 30:1 vol/vol and 435 rpms, respectively.

  8. Integrated Testing of a Carbon Dioxide Removal Assembly and a Temperature-Swing Adsorption Compressor for Closed-Loop Air Revitalization

    NASA Technical Reports Server (NTRS)

    Knox, J. C.; Mulloth, Lila; Frederick, Kenneth; Affleck, Dave

    2003-01-01

    Accumulation and subsequent compression of carbon dioxide that is removed from space cabin are two important processes involved in a closed-loop air revitalization scheme of the International Space Station (ISS). The carbon dioxide removal assembly (CDRA) of ISS currently operates in an open loop mode without a compressor. This paper describes the integrated test results of a flight-like CDRA and a temperature-swing adsorption compressor (TSAC) for carbon dioxide removal and compression. The paper provides details of the TSAC operation at various CO2 loadings and corresponding performance of CDRA.

  9. Bio-Conjugated CNT-Bridged 3D Porous Graphene Oxide Membrane for Highly Efficient Disinfection of Pathogenic Bacteria and Removal of Toxic Metals from Water.

    PubMed

    Nellore, Bhanu Priya Viraka; Kanchanapally, Rajashekhar; Pedraza, Francisco; Sinha, Sudarson Sekhar; Pramanik, Avijit; Hamme, Ashton T; Arslan, Zikri; Sardar, Dhiraj; Ray, Paresh Chandra

    2015-09-01

    More than a billion people lack access to safe drinking water that is free from pathogenic bacteria and toxic metals. The World Health Organization estimates several million people, mostly children, die every year due to the lack of good quality water. Driven by this need, we report the development of PGLa antimicrobial peptide and glutathione conjugated carbon nanotube (CNT) bridged three-dimensional (3D) porous graphene oxide membrane, which can be used for highly efficient disinfection of Escherichia coli O157:H7 bacteria and removal of As(III), As(V), and Pb(II) from water. Reported results demonstrate that versatile membrane has the capability to capture and completely disinfect pathogenic pathogenic E. coli O157:H7 bacteria from water. Experimentally observed disinfection data indicate that the PGLa attached membrane can dramatically enhance the possibility of destroying pathogenic E. coli bacteria via synergistic mechanism. Reported results show that glutathione attached CNT-bridged 3D graphene oxide membrane can be used to remove As(III), As(V), and Pb(II) from water sample at 10 ppm level. Our data demonstrated that PGLa and glutathione attached membrane has the capability for high efficient removal of E. coli O157:H7 bacteria, As(III), As(V), and Pb(II) simultaneously from Mississippi River water. PMID:26273843

  10. Bio-Conjugated CNT-Bridged 3D Porous Graphene Oxide Membrane for Highly Efficient Disinfection of Pathogenic Bacteria and Removal of Toxic Metals from Water.

    PubMed

    Nellore, Bhanu Priya Viraka; Kanchanapally, Rajashekhar; Pedraza, Francisco; Sinha, Sudarson Sekhar; Pramanik, Avijit; Hamme, Ashton T; Arslan, Zikri; Sardar, Dhiraj; Ray, Paresh Chandra

    2015-09-01

    More than a billion people lack access to safe drinking water that is free from pathogenic bacteria and toxic metals. The World Health Organization estimates several million people, mostly children, die every year due to the lack of good quality water. Driven by this need, we report the development of PGLa antimicrobial peptide and glutathione conjugated carbon nanotube (CNT) bridged three-dimensional (3D) porous graphene oxide membrane, which can be used for highly efficient disinfection of Escherichia coli O157:H7 bacteria and removal of As(III), As(V), and Pb(II) from water. Reported results demonstrate that versatile membrane has the capability to capture and completely disinfect pathogenic pathogenic E. coli O157:H7 bacteria from water. Experimentally observed disinfection data indicate that the PGLa attached membrane can dramatically enhance the possibility of destroying pathogenic E. coli bacteria via synergistic mechanism. Reported results show that glutathione attached CNT-bridged 3D graphene oxide membrane can be used to remove As(III), As(V), and Pb(II) from water sample at 10 ppm level. Our data demonstrated that PGLa and glutathione attached membrane has the capability for high efficient removal of E. coli O157:H7 bacteria, As(III), As(V), and Pb(II) simultaneously from Mississippi River water.

  11. Removal of toxic Co-EDTA complex by a halophilic solar-salt-pan isolate Pseudomonas aeruginosa SPB-1.

    PubMed

    Paraneeiswaran, A; Shukla, Sudhir K; Subba Rao, T; Prashanth, K

    2014-01-01

    In this study, a promising bioremediation approach was developed to remove [Co(III)-EDTA](-) complex that is generated during the waste management process. Though several studies have been reported on bioremediation of cobalt, the removal of [Co(III)-EDTA](-) complex has not been tested. A [Co(III)-EDTA](-) resistant bacterium, Pseudomonas aeruginosa SPB-1 was isolated from the solar-salt-pan and physical parameters were optimized for its growth. The various studies showed that the removal of [Co(III)-EDTA](-) from the bulk liquid was due to the adsorption of the complex by the biomass. Using absorption/desorption isotherm over a range of pH (1-8), the maximum adsorption of [Co(III)-EDTA](-) was found to be at pH 7.0 and maximum desorption from the biomass occurred at pH 1.0, thus rendering an ion exchange property to P. aeruginosa SPB-1 biomass. P. aeruginosa SPB-1 biomass could be used as bio-resin that showed 80.4±3.27% adsorption capacity up to fourth cycle and the biomass was viable till the ninth cycle with 10.5±7.3% adsorption. Radiation tolerance potential i.e. D10 value for the strain was found to be ~300 Gy, which suggests the potential use of the bacterium in bioremediation of moderately active nuclear waste.

  12. Visualization of removal of trapped air from the apical region in simulated root canals by laser-activated irrigation using an Er,Cr:YSGG laser.

    PubMed

    Peeters, Harry Huiz; De Moor, Roeland J G; Suharto, Djoko

    2015-08-01

    The aim of this visualization study was to obtain a better understanding of the mechanism by which trapped air is removed from the apical region of simulated root canals by activation of an irrigant using an erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser during endodontic procedures. A high-speed imaging system with high temporal and spatial resolution was used to visualize laser-induced shock waves in a resin block model with a curved root canal (inner diameter at the apex 0.08 mm, taper 4 %, crown height 10 mm, overall length 40 mm) and a glass cylinder model with a straight root canal (inner diameter 1 mm, crown height 10 mm, overall length 40 mm). The study utilized MZ3 and RFT3 tips in each model, without water or air spray, and with an average power of 1 W at 35 Hz. Laser-activated irrigation overcame the airlock effect by releasing air trapped in the air column. The mechanism underlying the removal of trapped air from the apical region using an Er,Cr:YSGG laser in a dry root canal is via the disruption of the surface tension at the solution-air interface. This disruption, caused by bubble implosion (cavitation), displaces air in the form of bubbles from the apical region toward the solution, which allows the solution to travel apically.

  13. Combining Experiments and Simulation of Gas Absorption for Teaching Mass Transfer Fundamentals: Removing CO2 from Air Using Water and NaOH

    ERIC Educational Resources Information Center

    Clark, William M.; Jackson, Yaminah Z.; Morin, Michael T.; Ferraro, Giacomo P.

    2011-01-01

    Laboratory experiments and computer models for studying the mass transfer process of removing CO2 from air using water or dilute NaOH solution as absorbent are presented. Models tie experiment to theory and give a visual representation of concentration profiles and also illustrate the two-film theory and the relative importance of various…

  14. Experimental investigations on decay heat removal in advanced nuclear reactors using single heater rod test facility: Air alone in the annular gap

    SciTech Connect

    Bopche, Santosh B.; Sridharan, Arunkumar

    2010-11-15

    During a loss of coolant accident in nuclear reactors, radiation heat transfer accounts for a significant amount of the total heat transfer in the fuel bundle. In case of heavy water moderator nuclear reactors, the decay heat of a fuel bundle enclosed in the pressure tube and outer concentric calandria tube can be transferred to the moderator. Radiation heat transfer plays a significant role in removal of decay heat from the fuel rods to the moderator, which is available outside the calandria tube. A single heater rod test facility is designed and fabricated as a part of preliminary investigations. The objective is to anticipate the capability of moderator to remove decay heat, from the reactor core, generated after shut down. The present paper focuses mainly on the role of moderator in removal of decay heat, for situation with air alone in the annular gap of pressure tube and calandria tube. It is seen that the naturally aspirated air is capable of removing the heat generated in the system compared to the standstill air or stagnant water situations. It is also seen that the flowing moderator is capable of removing a greater fraction of heat generated by the heater rod compared to a stagnant pool of boiling moderator. (author)

  15. Component modeling in ecological risk assessment: Disturbance in interspecific interactions caused by air toxics introduced into terrestrial ecosystems

    NASA Astrophysics Data System (ADS)

    Swider, Jan Zenon

    Ecological Risk Assessment standpoint and examine the impact of air toxics emissions on an ecosystem, with particular emphasis on predator-prey interactions. Such analysis may help to identify the most likely conditions leading to the ecosystem instability and possibility of its recuperation.

  16. Clinical evaluation of the air removal characteristics of an oxygenator with integrated arterial filter in a minimized extracorporeal circuit.

    PubMed

    Stehouwer, Marco C; Boers, Chris; de Vroege, Roel; C Kelder, Johannes; Yilmaz, Alaaddin; Bruins, Peter

    2011-04-01

    The use of minimized extracorporeal circuits (MECC) in cardiac surgery is an important measure to increase the biocompatibility of cardiopulmonary bypass during coronary artery bypass grafting (CABG). These circuits eliminate volume storage reservoirs and bubble traps to minimize the circuit. However, the reduction in volume may increase the risk of gaseous microemboli (GME). The MECC system as used by our group consists of a venous bubble trap, centrifugal pump, and an oxygenator. To further reduce the risk of introducing GME, an oxygenator with an integrated arterial filter was developed based on the concept of minimal volume and foreign surface. We studied the air removal characteristics of this oxygenator with and without integrated arterial filter. The quantity and volume of GME were measured with precision at both the inlet and outlet of the devices. Our results showed that integration of an arterial filter into this oxygenator increased GME reducing capacity from 69.2% to 92%. Moreover, we were able to obtain data on the impact of an arterial filter on the exact size-distribution of GME entering the arterial line. The present study demonstrates that an MECC system and oxygenator with integrated arterial filter significantly reduces the volume and size of GME. The use of an integrated arterial filter in an MECC system may protect the patient from the deleterious effects of CPB and may further improve patient safety.

  17. Improved chronic fatigue symptoms after removal of mercury in patient with increased mercury concentration in hair toxic mineral assay: a case.

    PubMed

    Shin, Sae-Ron; Han, A-Lum

    2012-09-01

    Clinical manifestations of chronic exposure to organic mercury usually have a gradual onset. As the primary target is the nervous system, chronic mercury exposure can cause symptoms such as fatigue, weakness, headache, and poor recall and concentration. In severe cases chronic exposure leads to intellectual deterioration and neurologic abnormality. Recent outbreaks of bovine spongiform encephalopathy and pathogenic avian influenza have increased fish consumption in Korea. Methyl-mercury, a type of organic mercury, is present in higher than normal ranges in the general Korean population. When we examine a patient with chronic fatigue, we assess his/her methyl-mercury concentrations in the body if environmental exposure such as excessive fish consumption is suspected. In the current case, we learned the patient had consumed many slices of raw tuna and was initially diagnosed with chronic fatigue syndrome. Therefore, we suspected that he was exposured to methyl-mercury and that the mercury concentration in his hair would be below the poisoning level identified by World Health Organization but above the normal range according to hair toxic mineral assay. Our patient's toxic chronic fatigue symptoms improved after he was given mercury removal therapy, indicating that he was correctly diagnosed with chronic exposure to organic mercury. PMID:23115707

  18. Toxicity of copper oxide nanoparticles in lung epithelial cells exposed at the air-liquid interface compared with in vivo assessment

    PubMed Central

    Jing, Xuefang; Park, Jae Hong; Peters, Thomas M.; Thorne, Peter S.

    2015-01-01

    The toxicity of spark-generated copper oxide nanoparticles (CuONPs) was evaluated in human bronchial epithelial cells (HBEC) and lung adenocarcinoma cells (A549 cells) using an in vitro air-liquid interface (ALI) exposure system. Dose-response results were compared to in vivo inhalation and instillation studies of CuONP. Cells were exposed to particle-free clean air (controls) or spark-generated CuONPs. The number median diameter, geometric standard deviation and total number concentration of CuONPs were 9.2 nm, 1.48 and 2.27×107 particles/cm3, respectively. Outcome measures included cell viability, cytotoxicity, oxidative stress and proinflammatory chemokine production. Exposure to clean air (2 or 4 hr) did not induce toxicity in HBEC or A549 cells. Compared with controls, CuONP exposures significantly reduced cell viability, increased lactate dehydrogenase (LDH) release and elevated levels of reactive oxygen species (ROS) and IL-8 in a dose-dependent manner. A549 cells were significantly more susceptible to CuONP effects than HBEC. Antioxidant treatment reduced CuONP-induced cytotoxicity. When dose was expressed per area of exposed epithelium there was good agreement of toxicity measures with murine in vivo studies. This demonstrates that in vitro ALI studies can provide meaningful data on nanotoxicity of metal oxides. PMID:25575782

  19. Effect of air-assisted backwashing on the performance of an anaerobic fixed-bed bioreactor that simultaneously removes nitrate and arsenic from drinking water sources.

    PubMed

    Upadhyaya, Giridhar; Clancy, Tara M; Snyder, Kathryn V; Brown, Jess; Hayes, Kim F; Raskin, Lutgarde

    2012-03-15

    Contaminant removal from drinking water sources under reducing conditions conducive for the growth of denitrifying, arsenate reducing, and sulfate reducing microbes using a fixed-bed bioreactor may require oxygen-free gas (e.g., N2 gas) during backwashing. However, the use of air-assisted backwashing has practical advantages, including simpler operation, improved safety, and lower cost. A study was conducted to evaluate whether replacing N2 gas with air during backwashing would impact performance in a nitrate and arsenic removing anaerobic bioreactor system that consisted of two biologically active carbon reactors in series. Gas-assisted backwashing, comprised of 2 min of gas injection to fluidize the bed and dislodge biomass and solid phase products, was performed in the first reactor (reactor A) every two days. The second reactor (reactor B) was subjected to N2 gas-assisted backwashing every 3-4 months. Complete removal of 50 mg/L NO3- was achieved in reactor A before and after the switch from N2-assisted backwashing (NAB) to air-assisted backwashing (AAB). Substantial sulfate removal was achieved with both backwashing strategies. Prolonged practice of AAB (more than two months), however, diminished sulfate reduction in reactor B somewhat. Arsenic removal in reactor A was impacted slightly by long-term use of AAB, but arsenic removals achieved by the entire system during NAB and AAB periods were not significantly different (p>0.05) and arsenic concentrations were reduced from approximately 200 μg/L to below 20 μg/L. These results indicate that AAB can be implemented in anaerobic nitrate and arsenic removal systems.

  20. Insecticide toxicity to Hyalella curvispina in runoff and stream water within a soybean farm (Buenos Aires, Argentina).

    PubMed

    Mugni, H; Ronco, A; Bonetto, C

    2011-03-01

    Toxicity to the locally dominant amphipod Hyalella curvispina was assessed in a first-order stream running through a cultivated farm. Cypermethrin, chlorpyrifos, endosulfan and glyphosate were sprayed throughout the studied period. Toxicity was assayed under controlled laboratory conditions with runoff and stream water samples taken from the field under steady state and flood conditions. Ephemeral toxicity pulses were observed as a consequence of farm pesticide applications. After pesticide application, runoff water showed 100% mortality to H. curvispina for 1 month, but no mortality thereafter. Toxicity persistence was shortest in stream water, intermediate in stream sediments and longest in soil samples. Runoff had a more important toxicity effect than the exposure to direct aerial fumigation. The regional environmental features determining fast toxicity dissipation are discussed.