Science.gov

Sample records for air contaminant concentrations

  1. Concentrations of selected contaminants in cabin air of airbus aircrafts.

    PubMed

    Dechow, M; Sohn, H; Steinhanses, J

    1997-07-01

    The concentrations of selected air quality parameters in aircraft cabins were investigated including particle numbers in cabin air compared to fresh air and recirculation air, the microbiological contamination and the concentration of volatile organic compounds (VOC). The Airbus types A310 of Swissair and A340 of Lufthansa were used for measurements. The particles were found to be mainly emitted by the passengers, especially by smokers. Depending on recirculation filter efficiency the recirculation air contained a lower or equal amount of particles compared to the fresh air, whereas the amount of bacteria exceeded reported concentrations within other indoor spaces. The detected species were mainly non-pathogenic, with droplet infection over short distances identified as the only health risk. The concentration of volatile organic compounds (VOC) were well below threshold values. Ethanol was identified as the compound with the highest amount in cabin air. Further organics were emitted by the passengers--as metabolic products or by smoking--and on ground as engine exhaust (bad airport air quality). Cleaning agents may be the source of further compounds.

  2. Modeling breathing-zone concentrations of airborne contaminants generated during compressed air spray painting.

    PubMed

    Flynn, M R; Gatano, B L; McKernan, J L; Dunn, K H; Blazicko, B A; Carlton, G N

    1999-01-01

    This paper presents a mathematical model to predict breathing-zone concentrations of airborne contaminants generated during compressed air spray painting in cross-flow ventilated booths. The model focuses on characterizing the generation and transport of overspray mist. It extends previous work on conventional spray guns to include exposures generated by HVLP guns. Dimensional analysis and scale model wind-tunnel studies are employed using non-volatile oils, instead of paint, to produce empirical equations for estimating exposure to total mass. Results indicate that a dimensionless breathing zone concentration is a nonlinear function of the ratio of momentum flux of air from the spray gun to the momentum flux of air passing through the projected area of the worker's body. The orientation of the spraying operation within the booth is also very significant. The exposure model requires an estimate of the contaminant generation rate, which is approximated by a simple impactor model. The results represent an initial step in the construction of more realistic models capable of predicting exposure as a mathematical function of the governing parameters.

  3. High Concentrations of Organic Contaminants in Air from Ship Breaking Activities in Chittagong, Bangladesh.

    PubMed

    Nøst, Therese H; Halse, Anne K; Randall, Scott; Borgen, Anders R; Schlabach, Martin; Paul, Alak; Rahman, Atiqur; Breivik, Knut

    2015-10-06

    The beaches on the coast of Chittagong in Bangladesh are one of the most intense ship breaking areas in the world. The aim of the study was to measure the concentrations of organic contaminants in the air in the city of Chittagong, including the surrounding ship breaking areas using passive air samplers (N = 25). The compounds detected in the highest amounts were the polycyclic aromatic hydrocarbons (PAHs) and short-chain chlorinated paraffins (SCCPs), whereas dichlorodiphenyltrichloroethanes (DDTs), hexachlorobenzene (HCB), and polychlorinated biphenyls (PCBs) were several orders of magnitude lower in comparison. PCBs, PAHs, and HCB were highest at sites near the ship breaking activities, whereas DDTs and SCCPs were higher in the urban areas. Ship breaking activities likely act as atmospheric emission sources of PCBs, PAHs, and HCB, thus adding to the international emphasis on responsible recycling of ships. Concentrations of PAHs, PCBs, DDTs, HCB, and SCCPs in ambient air in Chittagong are high in comparison to those found in similar studies performed in other parts of Asia. Estimated toxic equivalent quotients indicate elevated human health risks caused by inhalation of PAHs at most sites.

  4. Factors Affecting Indoor Air Concentrations of Volatile Organic Compounds at a Site of Subsurface Gasoline Contamination

    SciTech Connect

    Fischer, M.L.; Bentley, A.J.; Dunkin, K.A.; Hodgson, A.T.; Nazaroff, W.W.; Sextro, R.G.; Daisey, J.M.

    1995-11-01

    We report a field study of soil gas transport of volatile organic compounds (VOCs) into a slab-on-grade building found at a site contaminated with gasoline. Although the high VOC concentrations (30-60 g m{sup -3}) measured in the soil gas at depths of 0.7 m below the building suggest a potential for high levels of indoor VOC, the measured indoor air concentrations were lower than those in the soil gas by approximately six orders of magnitude ({approx} 0.03 mg m{sup -3}). This large ratio is explained by (1) the expected dilution of soil gas entering the building via ambient building ventilation (a factor of {approx}1000), and (2) an unexpectedly sharp gradient in soil gas VOC concentration between the depths of 0.1 and 0.7 m (a factor of {approx}1000). Measurements of the soil physical and biological characteristics indicate that a partial physical barrier to vertical transport in combination with microbial degradation provides a likely explanation for this gradient. These factors are likely to be important to varying degrees at other sites.

  5. Use of dust fall filters as passive samplers for metal concentrations in air for communities near contaminated mine tailings.

    PubMed

    Beamer, P I; Sugeng, A J; Kelly, M D; Lothrop, N; Klimecki, W; Wilkinson, S T; Loh, M

    2014-05-01

    Mine tailings are a source of metal exposures in many rural communities. Multiple air samples are necessary to assess the extent of exposures and factors contributing to these exposures. However, air sampling equipment is costly and requires trained personnel to obtain measurements, limiting the number of samples that can be collected. Simple, low-cost methods are needed to allow for increased sample collection. The objective of our study was to assess if dust fall filters can serve as passive air samplers and be used to characterize potential exposures in a community near contaminated mine tailings. We placed filters in cylinders, concurrently with active indoor air samplers, in 10 occupied homes. We calculated an estimated flow rate by dividing the mass on each dust fall filter by the bulk air concentration and the sampling duration. The mean estimated flow rate for dust fall filters was significantly different during sampling periods with precipitation. The estimated flow rate was used to estimate metal concentration in the air of these homes, as well as in 31 additional homes in another rural community impacted by contaminated mine tailings. The estimated air concentrations had a significant linear association with the measured air concentrations for beryllium, manganese and arsenic (p < 0.05), whose primary source in indoor air is resuspended soil from outdoors. In the second rural community, our estimated metal concentrations in air were comparable to active air sampling measurements taken previously. This passive air sampler is a simple low-cost method to assess potential exposures near contaminated mining sites.

  6. Control of aerosol contaminants in indoor air: combining the particle concentration reduction with microbial inactivation.

    PubMed

    Grinshpun, Sergey A; Adhikari, Atin; Honda, Takeshi; Kim, Ki Youn; Toivola, Mika; Rao, K S Ramchander; Reponen, Tiina

    2007-01-15

    An indoor air purification technique, which combines unipolar ion emission and photocatalytic oxidation (promoted by a specially designed RCI cell), was investigated in two test chambers, 2.75 m3 and 24.3 m3, using nonbiological and biological challenge aerosols. The reduction in particle concentration was measured size selectively in real-time, and the Air Cleaning Factor and the Clean Air Delivery Rate (CADR) were determined. While testing with virions and bacteria, bioaerosol samples were collected and analyzed, and the microorganism survival rate was determined as a function of exposure time. We observed that the aerosol concentration decreased approximately 10 to approximately 100 times more rapidly when the purifier operated as compared to the natural decay. The data suggest that the tested portable unit operating in approximately 25 m3 non-ventilated room is capable to provide CADR-values more than twice as great than the conventional closed-loop HVAC system with a rating 8 filter. The particle removal occurred due to unipolar ion emission, while the inactivation of viable airborne microorganisms was associated with photocatalytic oxidation. Approximately 90% of initially viable MS2 viruses were inactivated resulting from 10 to 60 min exposure to the photocatalytic oxidation. Approximately 75% of viable B. subtilis spores were inactivated in 10 min, and about 90% or greater after 30 min. The biological and chemical mechanisms that led to the inactivation of stress-resistant airborne viruses and bacterial spores were reviewed.

  7. Air Data - Concentration Map

    EPA Pesticide Factsheets

    Make a map of daily concentrations over several days. The daily air quality can be displayed in terms of the Air Quality Index or in concentration ranges for certain PM species like organic carbon, nitrates, and sulfates.

  8. Probabilistic approach to estimating indoor air concentrations of chlorinated volatile organic compounds from contaminated groundwater: a case study in San Antonio, Texas.

    PubMed

    Johnston, Jill E; Gibson, Jacqueline MacDonald

    2011-02-01

    This paper describes a probabilistic model, based on the Johnson-Ettinger algorithm, developed to characterize the current and historic exposure to tricholorethylene (TCE) and tetrachlorethylene (PCE) in indoor air from plumes of groundwater contamination emanating from the former Kelly Air Force Base in San Antonio, Texas. We estimate indoor air concentration, house by house, in 30 101 homes and compare the estimated concentrations with measured values in a small subset of homes. We also compare two versions of the Johnson-Ettinger model: one used by the Environmental Protection Agency (EPA) and another based on an alternative parametrization. The modeled mean predicted PCE concentration historically exceeded PCE screening levels (0.41 ug/m(3)) in 5.5% of houses, and the 95th percentile of the predicted concentration exceeded screening levels in 85.3% of houses. For TCE, the mean concentration exceeded the screening level (0.25 ug/m(3)) in 49% of homes, and the 95th percentile of the predicted concentration exceeded the screening level in 99% of homes. The EPA model predicts slightly lower indoor concentrations than the alternative parametrization. Comparison with measured samples suggests both models, with the inputs selected, underestimate indoor concentrations and that the 95th percentiles of the predicted concentrations are closer to measured concentrations than predicted mean values.

  9. An accurate derivation of the air dose-rate and the deposition concentration distribution by aerial monitoring in a low level contaminated area

    NASA Astrophysics Data System (ADS)

    Nishizawa, Yukiyasu; Sugita, Takeshi; Sanada, Yukihisa; Torii, Tatsuo

    2015-04-01

    Since 2011, MEXT (Ministry of Education, Culture, Sports, Science and Technology, Japan) have been conducting aerial monitoring to investigate the distribution of radioactive cesium dispersed into the atmosphere after the accident at the Fukushima Dai-ichi Nuclear Power Plant (FDNPP), Tokyo Electric Power Company. Distribution maps of the air dose-rate at 1 m above the ground and the radioactive cesium deposition concentration on the ground are prepared using spectrum obtained by aerial monitoring. The radioactive cesium deposition is derived from its dose rate, which is calculated by excluding the dose rate of the background radiation due to natural radionuclides from the air dose-rate at 1 m above the ground. The first step of the current method of calculating the dose rate due to natural radionuclides is calculate the ratio of the total count rate of areas where no radioactive cesium is detected and the count rate of regions with energy levels of 1,400 keV or higher (BG-Index). Next, calculate the air dose rate of radioactive cesium by multiplying the BG-Index and the integrated count rate of 1,400 keV or higher for the area where the radioactive cesium is distributed. In high dose-rate areas, however, the count rate of the 1,365-keV peak of Cs-134, though small, is included in the integrated count rate of 1,400 keV or higher, which could cause an overestimation of the air dose rate of natural radionuclides. We developed a method for accurately evaluating the distribution maps of natural air dose-rate by excluding the effect of radioactive cesium, even in contaminated areas, and obtained the accurate air dose-rate map attributed the radioactive cesium deposition on the ground. Furthermore, the natural dose-rate distribution throughout Japan has been obtained by this method.

  10. Scrubbing of contaminants from contaminated air streams with aerogel materials with optional photocatalytic destruction

    DOEpatents

    Attia, Yosry A.

    2000-01-01

    Disclosed is a method for separating a vaporous or gaseous contaminant from an air stream contaminated therewith. This method includes the steps of: (a) passing said contaminated air into a contact zone in which is disposed an aerogel material capable of selecting adsorbing said contaminant from air and therein contacting said contaminated air with an aerogel material; and (b) withdrawing from said zone, air depleted of said contaminant. For present purposes, "contaminant" means a material not naturally occurring in ambient air and/or a material naturally occurring in air but present at a concentration above that found in ambient air. Thus, the present invention scrubs (or treats) air for the purpose of returning it to its ambient composition. Also disclosed herein is a process for the photocatalytic destruction of contaminants from an air stream wherein the contaminated air stream is passed into a control cell or contact zone in which is disposed a photocatalytic aerogel and exposing said aerogel to ultraviolet (UV) radiation for photocatalytically destroying the adsorbed contaminant, and withdrawing from said cell an exhaust air stream depleted in said contaminant.

  11. Air contaminants in a submarine equipped with air independent propulsion.

    PubMed

    Persson, Ola; Ostberg, Christina; Pagels, Joakim; Sebastian, Aleksandra

    2006-11-01

    The Swedish Navy has operated submarines equipped with air independent propulsion for two decades. This type of submarine can stay submerged for periods far longer than other non-nuclear submarines are capable of. The air quality during longer periods of submersion has so far not been thoroughly investigated. This study presents results for a number of air quality parameters obtained during more than one week of continuous submerged operation. The measured parameters are pressure, temperature, relative humidity, oxygen, carbon dioxide, hydrogen, formaldehyde and other volatile organic compounds, ozone, nitrogen dioxide, particulate matter and microbiological contaminants. The measurements of airborne particles demonstrate that air pollutants typically occur at a low baseline level due to high air exchange rates and efficient air-cleaning devices. However, short-lived peaks with comparatively high concentrations occur, several of the sources for these have been identified. The concentrations of the pollutants measured in this study do not indicate a build-up of hazardous compounds during eight days of submersion. It is reasonable to assume that a substantial build-up of the investigated contaminants is not likely if the submersion period is prolonged several times, which is the case for modern submarines equipped with air independent propulsion.

  12. Spacecraft Maximum Allowable Concentrations for Airborne Contaminants

    NASA Technical Reports Server (NTRS)

    James, John T.

    2008-01-01

    The enclosed table lists official spacecraft maximum allowable concentrations (SMACs), which are guideline values set by the NASA/JSC Toxicology Group in cooperation with the National Research Council Committee on Toxicology (NRCCOT). These values should not be used for situations other than human space flight without careful consideration of the criteria used to set each value. The SMACs take into account a number of unique factors such as the effect of space-flight stress on human physiology, the uniform good health of the astronauts, and the absence of pregnant or very young individuals. Documentation of the values is given in a 5 volume series of books entitled "Spacecraft Maximum Allowable Concentrations for Selected Airborne Contaminants" published by the National Academy Press, Washington, D.C. These books can be viewed electronically at http://books.nap.edu/openbook.php?record_id=9786&page=3. Short-term (1 and 24 hour) SMACs are set to manage accidental releases aboard a spacecraft and permit risk of minor, reversible effects such as mild mucosal irritation. In contrast, the long-term SMACs are set to fully protect healthy crewmembers from adverse effects resulting from continuous exposure to specific air pollutants for up to 1000 days. Crewmembers with allergies or unusual sensitivity to trace pollutants may not be afforded complete protection, even when long-term SMACs are not exceeded. Crewmember exposures involve a mixture of contaminants, each at a specific concentration (C(sub n)). These contaminants could interact to elicit symptoms of toxicity even though individual contaminants do not exceed their respective SMACs. The air quality is considered acceptable when the toxicity index (T(sub grp)) for each toxicological group of compounds is less than 1, where T(sub grp), is calculated as follows: T(sub grp) = C(sub 1)/SMAC(sub 1) + C(sub 2/SMAC(sub 2) + ...+C(sub n)/SMAC(sub n).

  13. [Establishment of Assessment Method for Air Bacteria and Fungi Contamination].

    PubMed

    Zhang, Hua-ling; Yao, Da-jun; Zhang, Yu; Fang, Zi-liang

    2016-03-15

    In this paper, in order to settle existing problems in the assessment of air bacteria and fungi contamination, the indoor and outdoor air bacteria and fungi filed concentrations by impact method and settlement method in existing documents were collected and analyzed, then the goodness of chi square was used to test whether these concentration data obeyed normal distribution at the significant level of α = 0.05, and combined with the 3σ principle of normal distribution and the current assessment standards, the suggested concentrations ranges of air microbial concentrations were determined. The research results could provide a reference for developing air bacteria and fungi contamination assessment standards in the future.

  14. The index of microbial air contamination.

    PubMed

    Pasquarella, C; Pitzurra, O; Savino, A

    2000-12-01

    The standard index of microbial air contamination (IMA) for the measurement of microbial air contamination in environments at risk is described. The method quantifies the microbial flow directly related to the contamination of surfaces coming from microbes that reach critical points by falling on to them. The index of microbial air contamination is based on the count of the microbial fallout on to Petri dishes left open to the air according to the 1/1/1 scheme (for 1h, 1m from the floor, at least 1m away from walls or any obstacle). Classes of contamination and maximum acceptable levels have been established. The index of microbial air contamination has been tested in many different places: in hospitals, in food industries, in art galleries, aboard the MIR space station and also in the open air. It has proved to be a reliable and useful tool for monitoring the microbial surface contamination settling from the air in any environment.

  15. Air cleaning issues with contaminated sites

    SciTech Connect

    Bellamy, R.R.

    1997-08-01

    The US Nuclear Regulatory Commission has developed a list of contaminated sites that warrant special USNRC attention because they pose unique or complex decommissioning issues. This list of radiologically contaminated sites is termed the Site Decommissioning Management Plan (SDMP), and was first issued in 1990. A site is placed on the SDMP list if it has; (1) Problems with the viability of the responsible organization (e.g., the licensee for the site is unable or unwilling to pay for the decommissioning); (2) Large amounts of soil contamination or unused settling ponds or burial grounds that may make the waste difficult to dispose of; (3) The long-term presence of contaminated, unused buildings; (4) A previously terminated license; or (5) Contaminated or potential contamination of the ground water from on-site wastes. In deciding whether to add a site to the SDMP list, the NRC also considers the projected length of time for decommissioning and the willingness of the responsible organization to complete the decommissioning in a timely manner. Since the list was established, 9 sites have been removed from the list, and the current SDMP list contains 47 sites in 11 states. The USNRC annually publishes NUREG-1444, {open_quotes}Site Decommissioning Management Plan{close_quotes}, which updates the status of each site. This paper will discuss the philosophical goals of the SDMP, then will concentrate on the regulatory requirements associated with air cleaning issues at the SDMP sites during characterization and remediation. Both effluent and worker protection issues will be discussed. For effluents, the source terms at sites will be characterized, and measurement techniques will be presented. Off-site dose impacts will be included. For worker protection issues, air sampling analyses will be presented in order to show how the workers are adequately protected and their doses measured to satisfy regulatory criteria during decontamination operations. 1 tab.

  16. INDOOR AIR CONCENTRATION UNIT CONVERSIONS

    EPA Science Inventory

    Migration of volatile chemicals from the subsurface into overlying buildings is called vapor intrusion (VI). Volatile organic chemicals in contaminated soils or groundwater can emit vapors, which can migrate through subsurface soils and may enter the indoor air of overlying buil...

  17. Modeling, Monitoring and Fault Diagnosis of Spacecraft Air Contaminants

    NASA Technical Reports Server (NTRS)

    Ramirez, W. Fred; Skliar, Mikhail; Narayan, Anand; Morgenthaler, George W.; Smith, Gerald J.

    1996-01-01

    Progress and results in the development of an integrated air quality modeling, monitoring, fault detection, and isolation system are presented. The focus was on development of distributed models of the air contaminants transport, the study of air quality monitoring techniques based on the model of transport process and on-line contaminant concentration measurements, and sensor placement. Different approaches to the modeling of spacecraft air contamination are discussed, and a three-dimensional distributed parameter air contaminant dispersion model applicable to both laminar and turbulent transport is proposed. A two-dimensional approximation of a full scale transport model is also proposed based on the spatial averaging of the three dimensional model over the least important space coordinate. A computer implementation of the transport model is considered and a detailed development of two- and three-dimensional models illustrated by contaminant transport simulation results is presented. The use of a well established Kalman filtering approach is suggested as a method for generating on-line contaminant concentration estimates based on both real time measurements and the model of contaminant transport process. It is shown that high computational requirements of the traditional Kalman filter can render difficult its real-time implementation for high-dimensional transport model and a novel implicit Kalman filtering algorithm is proposed which is shown to lead to an order of magnitude faster computer implementation in the case of air quality monitoring.

  18. CONCENTRATION OF TETRACHLOROETHYLENE IN INDOOR AIR AT A FORMER DRY CLEANER FACILITY AS A FUNCTION OF SUBSURFACE CONTAMINATION: A CASE STUDY

    EPA Science Inventory

    A field study was performed to evaluate indoor air concentrations and vapor intrusion (VI) of tetrachloroethylene (PCE) and other chlorinated solvents at a commercial retail site in Dallas, TX. The building is approximately 40 years old and once housed a dry cleaning operation. R...

  19. Concentration of tetrachloroethylene in indoor air at a former dry cleaner facility as a function of subsurface contamination: a case study.

    PubMed

    Eklund, Bart M; Simon, Michelle A

    2007-06-01

    A field study was performed to evaluate indoor air concentrations and vapor intrusion (VI) of tetrachloroethylene (PCE) and other chlorinated solvents at a commercial retail site in Dallas, TX. The building is approximately 40 yr old and once housed a dry cleaning operation. Results from an initial site characterization were used to select sampling locations for the VI study. The general approach for evaluating VI was to collect time-integrated canister samples for off-site U.S. Environmental Protection Agency Method TO-15 analyses. PCE and other chlorinated solvents were measured in shallow soil gas, subslab soil-gas, indoor air, and ambient air. The subslab soil gas exhibited relatively high values: PCE < or =2,600,000 parts per billion by volume (ppbv) and trichloroethylene < or =170 ppbv. The attenuation factor, the ratio of indoor air and subslab soil-gas concentrations, was unusually low: approximately 5 x 10(-6) based on the maximum subslab soil-gas concentration of PCE and 1.4 x 10(-5) based on average values.

  20. Ambient air contamination: Characterization and detection techniques

    NASA Technical Reports Server (NTRS)

    Nulton, C. P.; Silvus, H. S.

    1985-01-01

    Techniques to characterize and detect sources of ambient air contamination are described. Chemical techniques to identify indoor contaminants are outlined, they include gas chromatography, or colorimetric detection. Organics generated from indoor materials at ambient conditions and upon combustion are characterized. Piezoelectric quartz crystals are used as precision frequency determining elements in electronic oscillators.

  1. Spacecraft Maximum Allowable Concentrations for Selected Airborne Contaminants. Volume 2

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The National Aeronautics and Space Administration (NASA) is aware of the potential toxicological hazards to humans that might be associated with prolonged spacecraft missions. Despite major engineering advances in controlling the atmosphere within spacecraft, some contamination of the air appears inevitable. NASA has measured numerous airborne contaminants during space missions. As the missions increase in duration and complexity, ensuring the health and well-being of astronauts traveling and working in this unique environment becomes increasingly difficult. As part of its efforts to promote safe conditions aboard spacecraft, NASA requested the National Research Council (NRC) to develop guidelines for establishing spacecraft maximum allowable concentrations (SMACs) for contaminants, and to review SMACs for various space-craft contaminants to determine whether NASA's recommended exposure limits are consistent with the guidelines recommended by the subcommittee. In response to NASA's request, the NRC organized the Subcommittee on Guidelines for Developing Spacecraft Maximum Allowable Concentrations for Space Station Contaminants within the Committee On Toxicology (COT). In the first phase of its work, the subcommittee developed the criteria and methods for preparing SMACs for spacecraft contaminants. The subcommittee's report, entitled Guidelines for Developing Spacecraft Maximum Allowable Concentrations for Space Station Contaminants, was published in 1992. The executive summary of that report is reprinted as Appendix A of this volume. In the second phase of the study, the Subcommittee on Spacecraft Maximum Allowable Concentrations reviewed reports prepared by NASA scientists and contractors recommending SMACs for approximately 35 spacecraft contaminants. The subcommittee sought to determine whether the SMAC reports were consistent with the 1992 guidelines. Appendix B of this volume contains the SMAC reports for 12 chemical contaminants that have been reviewed for

  2. Air-quality monitoring and detection of air contamination in an enclosed environment.

    PubMed

    Skliar, M; Ramirez, W F

    1997-01-01

    We report on the development of an air-quality monitoring and early detection system for an enclosed environment with specific emphasis on manned spacecraft. The proposed monitoring approach is based on a distributed parameter model of contaminant dispersion and real-time contaminant concentration measurements. Kalman filtering is identified as a suitable method for generating on-line estimation of the spatial contamination profile, and an implicit Kalman filtering algorithm is shown to be preferable for rear-time implementation. The identification of the contaminant concentration profile allows for a straightforward solution of the early detection of an air contamination event and provides information that enables potential automatic diagnosis of an unknown contamination source.

  3. Environmental Contaminants in Wildlife: Interpreting Tissue Concentrations

    USGS Publications Warehouse

    1996-01-01

    Covers the complex issue of how to evaluate contaminants in wildlife. This comprehensive resource deals with the question: 'How much of a chemical in the tissues of an animal is harmful?' Features: Authoritative and sound advice is provided on many environmental contaminants, including what the contaminants are and how to interpret the data on them. Each chapter includes a review of the literature on a specific chemical, followed by a clear technical summary that provides research guidance. Direction is given on how to interpret data that are sometimes conflicting or insufficient. Data are presented in easy to use tables. Primary attention is given to toxic concentrations of contaminants such as organochlorine pesticides, PCBs, dioxins, PAHs, metals, and fluorides.

  4. RADIAL COMPUTED TOMOGRAPHY OF AIR CONTAMINANTS USING OPTICAL REMOTE SENSING

    EPA Science Inventory

    The paper describes the application of an optical remote-sensing (ORS) system to map air contaminants and locate fugitive emissions. Many ORD systems may utilize radial non-overlapping beam geometry and a computed tomography (CT) algorithm to map the concentrations in a plane. In...

  5. Determination of tricresyl phosphate air contamination in aircraft.

    PubMed

    Denola, G; Hanhela, P J; Mazurek, W

    2011-08-01

    Monitoring of tricresyl phosphate (TCP) contamination of cockpit air was undertaken in three types of military aircraft [fighter trainer (FT), fighter bomber (FB), and cargo transport (CT) aircraft]. The aircraft had a previous history of pilot complaints about cockpit air contamination suspected to originate from the engine bleed air supply through the entry of aircraft turbine engine oil (ATO) into the engine compressor. Air samples were collected in flight and on the ground during engine runs using sorbent tubes packed with Porapak Q and cellulose filters. A total of 78 air samples were analysed, from 46 different aircraft, and 48 samples were found to be below the limit of detection. Nine incidents of smoke/odour were identified during the study. The concentrations of toxic o-cresyl phosphate isomers were below the level of detection in all samples. The highest total TCP concentration was 51.3 μg m(-3), while most were generally found to be <5 μg m(-3) compared with the 8-h time-weighted average exposure limit of 100 μg m(-3) for tri-o-cresyl phosphate. The highest concentrations were found at high engine power. Although TCP contamination of cabin/cockpit air has been the subject of much concern in aviation, quantitative data are sparse.

  6. Air Contamination With Fungals In Museum

    NASA Astrophysics Data System (ADS)

    Scarlat, Iuliana; Haiducu, Maria; Stepa, Raluca

    2015-07-01

    The aim of the studies was to determine the level and kind of fungal contamination of air in museum, deposits patrimony, restoration and conservation laboratories and their effects on health of workers. Microbiological air purity was measured with a SAS-100 Surface Air System impactor. The fungal contamination was observed in all 54 rooms where we made determinations. The highest levels of fungal were recorded at rooms with hygroscopic patrimony objects, eg carpets, chairs, upholstered chairs, books etc. The most species identified included under common allergens: Aspergillus, Penicillium, and Mucor. There fungal species belonging to the genus identified in this study, can trigger serious diseases museum workers, such as for example Aspergillus fumigatus, known allergies and toxic effects that may occur. In some places of the museum, occupational exposure limit values to fungi present in the air in the work environment, recommended by the specialized literature, have been overcome.

  7. ASSESSING ALLERGENICITY OF INDOOR AIR FUNGAL CONTAMINANTS

    EPA Science Inventory

    Assessing Allergenicity of Indoor Air Fungal Contaminants
    M D W Ward1, M E Viana2, N Haykal-Coates1, L B Copeland1, S H Gavett1, and MJ K Selgrade1. 1US EPA, ORD, NHEERL, RTP, NC, USA. 2NCSU, CVM, Raleigh, NC, USA.
    Rationale: The indoor environment has increased in impor...

  8. Fungi as contaminants in indoor air

    NASA Astrophysics Data System (ADS)

    Miller, J. David

    This article reviews the subject of contamination of indoor air with fungal spores. In the last few years there have been advances in several areas of research on this subject. A number of epidemiological studies have been conducted in the U.K., U.S.A. and Canada. These suggest that exposure to dampness and mold in homes is a significant risk factor for a number of respiratory symptoms. Well-known illnesses caused by fungi include allergy and hypersensitivity pneumonitis. There is now evidence that other consequences of exposure to spores of some fungi may be important. In particular, exposure to low molecular weight compounds retained in spores of some molds such as mycotoxins and β 1,3 glucans appears to contribute to some symptoms reported. Fungal contamination of building air is almost always caused by poor design and/or maintenance. Home owners and building operators need to take evidence of fungal contamination seriously.

  9. Spacecraft Maximum Allowable Concentrations for Selected Airborne Contaminants. Volume 5

    NASA Technical Reports Server (NTRS)

    2008-01-01

    To protect space crews from air contaminants, NASA requested that the National Research Council (NRC) provide guidance for developing spacecraft maximum allowable concentrations (SMACs) and review NASA's development of exposure guidelines for specific chemicals. The NRC convened the Committee on Spacecraft Exposure Guidelines to address this task. The committee published Guidelines for Developing Spacecraft Maximum Allowable Concentrations for Space Station Contaminants (NRC 1992). The reason for the review of chemicals in Volume 5 is that many of them have not been examined for more than 10 years, and new research necessitates examining the documents to ensure that they reflect current knowledge. New knowledge can be in the form of toxicologic data or in the application of new approaches for analysis of available data. In addition, because NASA anticipates longer space missions beyond low Earth orbit, SMACs for 1,000-d exposures have also been developed.

  10. Estimation of contaminant subslab concentration in vapor intrusion.

    PubMed

    Yao, Yijun; Pennell, Kelly G; Suuberg, Eric M

    2012-09-15

    This study is concerned with developing a method to estimate subslab perimeter crack contaminant concentration for structures built atop a vapor source. A simple alternative to the widely-used but restrictive one-dimensional (1-D) screening models is presented and justified by comparing to predictions from a three-dimensional (3-D) CFD model. A series of simulations were prepared for steady-state transport of a non-biodegradable contaminant in homogenous soil for different structure construction features and site characteristics. The results showed that subslab concentration does not strongly depend on the soil diffusivity, indoor air pressure, or foundation footprint size. It is determined by the geometry of the domain, represented by a characteristic length which is the ratio of foundation depth to source depth. An extension of this analytical approximation was developed for multi-layer soil cases.

  11. Estimation of contaminant subslab concentration in vapor intrusion

    PubMed Central

    Yao, Yijun; Pennell, Kelly G.; Suuberg, Eric M.

    2012-01-01

    This study is concerned with developing a method to estimate subslab perimeter crack contaminant concentration for structures built atop a vapor source. A simple alternative to the widely-used but restrictive one-dimensional (1-D) screening models is presented and justified by comparing to predictions from a three-dimensional (3-D) CFD model. A series of simulations were prepared for steady-state transport of a non-biodegradable contaminant in homogenous soil for different structure construction features and site characteristics. The results showed that subslab concentration does not strongly depend on the soil diffusivity, indoor air pressure, or foundation footprint size. It is determined by the geometry of the domain, represented by a characteristic length which is the ratio of foundation depth to source depth. An extension of this analytical approximation was developed for multi-layer soil cases. PMID:22776832

  12. Control of gas contaminants in air streams through biofiltration

    SciTech Connect

    Holt, T.; Lackey, L.

    1996-11-01

    According to the National Institute for Occupational Safety and Health (NIOSH), the maximum styrene concentration allowed in the work place is 50 ppm for up to a 10-hour work day during a 40-hour work week. The US EPA has classified styrene as one of the 189 hazardous air pollutants listed under Title 3 of the Clean Air Act Amendments to be reduced by a factor of 90% by the year 2000. Significant quantities of styrene are emitted to the atmosphere each year by boat manufacturers. A typical fiberglass boat manufacturing facility can emit over 273 metric tons/year of styrene. The concentration of styrene in the industrial exhaust gas ranges from 20 to 100 ppmv. Such dilute, high volume organically tainted air streams can make conventional abatement technologies such as thermal incineration, adsorption, or absorption technically incompetent or prohibitively expensive. An efficient, innovative, and economical means of remediating styrene vapors would be of value to industries and to the environment. Biofilter technology depends on microorganisms that are immobilized on the packing material in a solid phase reactor to remove or degrade environmentally undesirable compounds contaminating gas streams. The technology is especially successful for treating large volumes of air containing low concentrations of contaminants. The objective of this study was to investigate the feasibility of using biofiltration to treat waste gas streams containing styrene and to determine the critical design and operating parameters for such a system.

  13. Microbial air contamination in indoor environment of a university library.

    PubMed

    Kalwasińska, Agnieszka; Burkowska, Aleksandra; Wilk, Iwona

    2012-01-01

    The present study was aimed at evaluating the number of bacteria and mould fungi in the indoor and outdoor environment of Toruń University Library. The sampling sites were located in the rooms serving the functions typical of libraries (i.e. in the Main Reading Room, Current Periodicals Reading Room, Collections Conservation Laboratory, Old Prints Storeroom, in rooms serving other (non-library) functions (i.e. main hall, cafeteria, and toilet) as well as outside the library building. The analyses reveal that the concentrations of bacterial as well as fungal aerosols estimated with the use of the impaction method ranged between 10(1)-10(3) CFU·m(-3), which corresponds to the concentrations normally observed in areas of this kind. Evaluation of the hygienic condition of the studied areas was based on the criteria for microbiological cleanliness in interiors submitted by the European Commission in 1993. According to this classification, the air was considered to be heavily or moderately contaminated with bacteria, while the air contamination with mould fungi was described as low or moderate. The air in the Old Prints Storeroom was considered the least contaminated with microbial aerosol.

  14. Air Contamination by Mercury, Emissions and Transformations-a Review.

    PubMed

    Gworek, Barbara; Dmuchowski, Wojciech; Baczewska, Aneta H; Brągoszewska, Paulina; Bemowska-Kałabun, Olga; Wrzosek-Jakubowska, Justyna

    2017-01-01

    The present and future air contamination by mercury is and will continue to be a serious risk for human health. This publication presents a review of the literature dealing with the issues related to air contamination by mercury and its transformations as well as its natural and anthropogenic emissions. The assessment of mercury emissions into the air poses serious methodological problems. It is particularly difficult to distinguish between natural and anthropogenic emissions and re-emissions from lands and oceans, including past emissions. At present, the largest emission sources include fuel combustion, mainly that of coal, and "artisanal and small-scale gold mining" (ASGM). The distinctly highest emissions can be found in South and South-East Asia, accounting for 45% of the global emissions. The emissions of natural origin and re-emissions are estimated at 45-66% of the global emissions, with the largest part of emissions originating in the oceans. Forecasts on the future emission levels are not unambiguous; however, most forecasts do not provide for reductions in emissions. Ninety-five percent of mercury occurring in the air is Hg(0)-GEM, and its residence time in the air is estimated at 6 to 18 months. The residence times of its Hg(II)-GOM and that in Hgp-TPM are estimated at hours and days. The highest mercury concentrations in the air can be found in the areas of mercury mines and those of ASGM. Since 1980 when it reached its maximum, the global background mercury concentration in the air has remained at a relatively constant level.

  15. Biofiltration of trichloroethylene-contaminated air: a pilot study.

    PubMed

    Lackey, Laura W; Gamble, Johnny R; Boles, Jeffrey L

    2003-10-01

    This project demonstrated the biofiltration of a trichloroethylene (TCE)-contaminated airstream generated by air stripping groundwater obtained from several wells located at the Anniston Army Depot, Anniston, AL. The effects of several critical process variables were investigated to evaluate technical and economic feasibility, define operating limits and preferred operating conditions, and develop design information for a full-scale biofilter system. Long-term operation of the demonstration biofilter system was conducted to evaluate the performance and reliability of the system under variable weather conditions. Propane was used as the primary substrate necessary to induce the production of a nonspecific oxygenase. Results indicated that the process scheme used to introduce propane into the biofiltration system had a significant impact on the observed TCE removal efficiency. TCE degradation rates were dependent on the inlet contaminant concentration as well as on the loading rate. No microbial inhibition was observed at inlet TCE concentrations as high as 87 parts per million on a volume basis.

  16. Surface contamination artificially elevates initial sweat mineral concentrations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During exercise in the heat, sweat is initially concentrated in minerals, but serial sweat samples appear more dilute. Possible causes include reduced dermal mineral concentrations or flushing of surface contamination. PURPOSE: To simultaneously sample mineral concentrations in transdermal fluid (T...

  17. Air concentrations of organochlorine compounds related to wind direction and compared with biota concentration

    SciTech Connect

    Egebaeck, A.L.; Wideqvist, U.; Asplund, L.; Strandell, M.; Alsberg, T.; Litzen, K.; Eriksson, U.; Haeggberg, L.; Zakrisson, S.; Oisson, M.; Bignert, A.

    1995-12-31

    Persistent organic compounds are long-range transported by air. Air samples were collected at two background meteorological stations, one southern at Gotland in the central Baltic and one northern, close to the polar circle. The collection was a part of the Swedish Dioxin Survey Project. Air sampling was carried out from fall 1990 to spring 1991 using a high-volume sampler. Air trajectories suggesting stable weather conditions decided which samples to be analyzed for e.g. PCBs, polychlorinated naphthalenes (PCN), chloroparaffines, HCHs and Toxaphene. The gas-phase concentrations of the seven PCB congeners 28, 52, 101, 118, 138, 153, 180 were in the low pg/m{sup 3} range, while the concentration of the nonortho PCB 77 was about two orders of magnitude lower. High concentrations were usually correlated with SW winds and low concentrations with N to NW winds. Air masses coming from N to both sampling sites, resulted in nearly equal concentrations of the seven PCB congeners. PCNs were found in the gas phase of all samples at the pg/m{sup 3} level (total PCNs). The relative concentrations of the various contaminants were compared between air and four biological matrices collected in the vicinity of the air sampling locations. Cod, Herring and Herring feeding Guillemot from the Baltic and Pike from the northern sampling site were all collected within the Swedish National Monitoring Program.

  18. Ambient and Emission Trends of Toxic Air Contaminants in California.

    PubMed

    Propper, Ralph; Wong, Patrick; Bui, Son; Austin, Jeff; Vance, William; Alvarado, Álvaro; Croes, Bart; Luo, Dongmin

    2015-10-06

    After initiating a toxic air contaminant (TAC) identification and control program in 1984, the California Air Resources Board adopted regulations to reduce TAC emissions from cars, trucks, stationary sources, and consumer products. This study quantifies ambient concentration and emission trends for the period 1990-2012 for seven TACs that are responsible for most of the known cancer risk associated with airborne exposure in California. Of these seven, diesel particulate matter (DPM) is the most important; however DPM is not measured directly. Based on a novel surrogate method, DPM concentrations declined 68%, even though the state's population increased 31%, diesel vehicle-miles-traveled increased 81%, and the gross state product (GSP) increased 74%. Based on monitoring data, concentrations of benzene, 1,3-butadiene, perchloroethylene, and hexavalent chromium declined 88-94%. Also, the ambient and emissions trends for each of these four TACs were similar. Furthermore, these declines generally occurred earlier in California than elsewhere. However, formaldehyde and acetaldehyde, which are formed in the air photochemically from volatile organic compounds (VOCs), declined only 20-21%. The collective cancer risk from exposure to these seven reviewed TACs declined 76%. Significant reduction in cancer risk to California residents from implementation of air toxics controls (especially for DPM) is expected to continue.

  19. Mold contamination and air handling units.

    PubMed

    Wilson, Stephen C; Palmatier, Robert N; Andriychuk, Larysa A; Martin, Jared M; Jumper, Cynthia A; Holder, Homer W; Straus, David C

    2007-07-01

    An investigation was conducted on selected locations in air handling units (AHUs) to (a) identify common mold species found on these locations, (b) determine whether some locations (and subsets) featured mold growth sites more frequently than others, (c) ascertain whether the operating condition of AHUs is related to mold contamination, and (d) provide a basis for a microbial sampling protocol for AHUs. A total of 566 tape lifts and 570 swab samples were collected from the blower wheel fan blades, insulation, cooling coil fins, and ductwork from 25 AHUs. All AHU conditions were numerically rated using a heating, ventilation and air-conditioning (HVAC) survey. Results showed that Cladosporium sp. fungi were commonly recovered in terms of growth sites and deposited spores, and they were found mainly in the blower wheel fan blades, the ductwork, and the cooling coil fins. Subsections of the fan blades, insulation, and cooling coil fins showed no preferred area for mold growth sites. Other organisms such as Penicillium sp., Aspergillus sp., and Paecilomyces sp. were recovered from the cooling coil fins and insulation. Because of the widespread prevalence of Cladosporium sp., there was no relationship between mold growth and operating condition. However, the presence of different species of molds in locations other than the blower wheel blades may indicate that the AHU condition is not optimal. A suggested microbial sampling protocol including interpretations of sample results is presented.

  20. Methodology for Modeling the Microbial Contamination of Air Filters

    PubMed Central

    Joe, Yun Haeng; Yoon, Ki Young; Hwang, Jungho

    2014-01-01

    In this paper, we propose a theoretical model to simulate microbial growth on contaminated air filters and entrainment of bioaerosols from the filters to an indoor environment. Air filter filtration and antimicrobial efficiencies, and effects of dust particles on these efficiencies, were evaluated. The number of bioaerosols downstream of the filter could be characterized according to three phases: initial, transitional, and stationary. In the initial phase, the number was determined by filtration efficiency, the concentration of dust particles entering the filter, and the flow rate. During the transitional phase, the number of bioaerosols gradually increased up to the stationary phase, at which point no further increase was observed. The antimicrobial efficiency and flow rate were the dominant parameters affecting the number of bioaerosols downstream of the filter in the transitional and stationary phase, respectively. It was found that the nutrient fraction of dust particles entering the filter caused a significant change in the number of bioaerosols in both the transitional and stationary phases. The proposed model would be a solution for predicting the air filter life cycle in terms of microbiological activity by simulating the microbial contamination of the filter. PMID:24523908

  1. Indoor air VOC concentrations in suburban and rural New Jersey.

    PubMed

    Weisel, Clifford P; Alimokhtari, Shahnaz; Sanders, Paul F

    2008-11-15

    Indoor VOC air concentrations of many compounds are higher than outdoor concentrations due to indoor sources. However, most studies have measured residential indoor air in urban centers so the typical indoor air levels in suburban and rural regions have not been well characterized. Indoor VOC air concentrations were measured in 100 homes in suburban and rural areas in NJ to provide background levels for investigations of the impact from subsurface contamination sources. Of the 57 target compounds, 23 were not detected in any of the homes, and 14 compounds were detected in at least 50% of the homes with detection limits of approximately 1 microg/m3. The common compounds identified included aromatic and aliphatic hydrocarbons from mobile sources, halogenated hydrocarbons commonly used in consumer products or from chlorinated drinking water, acetone and 2-butanone emitted from cosmetic products, and Freons. Typical concentrations were in the low microg/m3 range, though values of tens, hundreds or even thousands of microg/m3 were measured in individual homes in which activities related to specific sources of VOCs were reported. Compounds with known similar sources were highly correlated. The levels observed are consistent with concentrations found in the air of urban homes.

  2. Influence of relative humidity on VOC concentrations in indoor air.

    PubMed

    Markowicz, Pawel; Larsson, Lennart

    2015-04-01

    Volatile organic compounds (VOCs) may be emitted from surfaces indoors leading to compromised air quality. This study scrutinized the influence of relative humidity (RH) on VOC concentrations in a building that had been subjected to water damage. While air samplings in a damp room at low RH (21-22%) only revealed minor amounts of 2-ethylhexanol (3 μg/m(3)) and 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (TXIB, 8 μg/m(3)), measurements performed after a rapid increase of RH (to 58-75%) revealed an increase in VOC concentrations which was 3-fold for 2-ethylhexanol and 2-fold for TXIB. Similar VOC emission patterns were found in laboratory analyses of moisture-affected and laboratory-contaminated building materials. This study demonstrates the importance of monitoring RH when sampling indoor air for VOCs in order to avoid misleading conclusions from the analytical results.

  3. A source of PCB contamination in modified high-volume air samplers

    SciTech Connect

    Basu, I.; O'Dell, J.M.; Arnold, K.; Hites, R.A.

    2000-02-01

    Modified Anderson High Volume (Hi-Vol) air samplers are widely used for the collection of semi-volatile organic compounds (such as PCBs) from air. The foam gasket near the main air flow path in these samplers can become contaminated with PCBs if the sampler or the gasket is stored at a location with high indoor air PCB levels. Once the gasket is contaminated, it releases PCBs back into the air stream during sampling, and as a result, incorrectly high air PCB concentrations are measured. This paper presents data demonstrating this contamination problem using measurements from two Integrated Atmospheric Deposition Network sites: one at Sleeping Bear Dunes on Lake Michigan and the other at Point Petre on Lake Ontario. The authors recommend that these gaskets be replaced by Teflon tape and that the storage history of each sampler be carefully tracked.

  4. Electrets to measure ion concentration in air.

    PubMed

    Kotrappa, P

    2005-08-01

    Positive and negative ions are produced in air, mainly due to radon and terrestrial/cosmic radiation sources. Measuring ion concentration in air indirectly provides a measure of these sources. Electrets (electrically charged pieces of Teflon), when exposed in the environment, collect ions of opposite sign leading to a measurable decrease in charge, depending upon the exposure time and ion concentration. This work describes a method of correlating electret discharge rate to the ion concentration as measured by a calibrated ion density meter. Once calibrated, electrets can then be used to measure ion concentration of either sign. The ion concentration in ambient air was measured to be about 200 ions mL(-1), measured over several hours. Both positive and negative ion concentrations were similar. In a typical room, negative ion concentration was about 3,500 ions mL(-1), and, surprisingly, there were no positive ions at all in that room. Being an integrating passive device, the method provides the unique possibility of measuring low or high concentrations of positive or negative ions over extended periods, which is difficult to do with other ion concentration measuring instruments.

  5. Regenerable Air Purification System for Gas-Phase Contaminant Control

    NASA Technical Reports Server (NTRS)

    Constantinescu, Ileana C.; Finn, John E.; LeVan, M. Douglas; Lung, Bernadette (Technical Monitor)

    2000-01-01

    Tests of a pre-prototype regenerable air purification system (RAPS) that uses water vapor to displace adsorbed contaminants from an adsorbent column have been performed at NASA Ames Research Center. A unit based on this design can be used for removing trace gas-phase contaminants from spacecraft cabin air or from polluted process streams including incinerator exhaust. During the normal operation mode, contaminants are removed from the air on the column. Regeneration of the column is performed on-line. During regeneration, contaminants are displaced and destroyed inside the closed oxidation loop. In this presentation we discuss initial experimental results for the performance of RAPS in the removal and treatment of several important spacecraft contaminant species from air.

  6. The Air Force concentrating photovoltaic array program

    NASA Technical Reports Server (NTRS)

    Geis, Jack W.

    1987-01-01

    A summary is given of Air Force solar concentrator projects beginning with the Rockwell International study program in 1977. The Satellite Materials Hardening Programs (SMATH) explored and developed techniques for hardening planar solar cell array power systems to the combined nuclear and laser radiation threat environments. A portion of program dollars was devoted to developing a preliminary design for a hardened solar concentrator. The results of the Survivable Concentrating Photovoltaic Array (SCOPA) program, and the design, fabrication and flight qualification of a hardened concentrator panel are discussed.

  7. Possible implication of sterile connecting device in contamination of pooled platelet concentrates.

    PubMed

    Mertens, G; Muylle, L; Goossens, H

    1997-09-01

    Considering the possibility that a pooled random donor platelet concentrate could become contaminated by welding with a sterile connecting device, we undertook a study to determine the influence of pooling on the contamination rate. As a control group, apheresis platelets were examined. Bacteriological testing was done with a sensitive CO2 detecting culture system, the BacT/ Alert. Out of 1105 pooled platelet concentrates prepared by the buffy coat method, 15 (1.4%) were confirmed as contaminated, all with Staphylococcus epidermidis and two with a second bacterial species, i.e. Staphylococcus capitis and Propionibacterium acnes, respectively. Median detection time by the BacT/Alert was 23 h. Twelve pools of five units were contaminated, which is significantly more than the three contaminated pools of four units. On the other hand, the reuse of the welding wafers proved not be a risk factor for contamination. One welded tubing segment of a contaminated platelet concentrate failed the air leakage test, an incident which was 73 times more frequent than with the sterile platelet concentrates. We found five pooled platelet concentrates containing Staphylococci from which no bacteria could be grown from the individual buffy coats that had been pooled. We suggest the contamination here to have occurred after separation of the buffy coat from the whole blood, possibly during the welding process. Finally, none out of 378 apheresis platelet concentrates was contaminated. All our observations highlight the potential risk for contamination when making pooled platelet concentrates with a sterile connecting device. For this type of transfusion product, we advocate bacteriological screening of all units before release. The incubation time for the sterility test should, however, be limited to 36 h, if logistical problems with the availability of platelets are to be avoided.

  8. Observations on using inside air concentrations as a predictor of outside air concentrations

    SciTech Connect

    Hawkley, Gavin; Whicker, Jeffrey; Harris, Jason

    2015-04-01

    Here, excavations of radiological material were performed within confined structures with known operational parameters, such as a filtered exhaust system with known filtration efficiency. Given the known efficiency, the assumption could be made that the air concentrations of radioactivity measured outside the structure would be proportional to the air concentrations measured inside the structure. To investigate this assumption, the inside concentration data was compared with the outside concentration data. The correlation of the data suggested that the inside concentrations were not a good predictor of the outside concentrations. This poor correlation was deemed to be a result of operational unknowns within the structures.

  9. Observations on using inside air concentrations as a predictor of outside air concentrations

    DOE PAGES

    Hawkley, Gavin; Whicker, Jeffrey; Harris, Jason

    2015-04-01

    Here, excavations of radiological material were performed within confined structures with known operational parameters, such as a filtered exhaust system with known filtration efficiency. Given the known efficiency, the assumption could be made that the air concentrations of radioactivity measured outside the structure would be proportional to the air concentrations measured inside the structure. To investigate this assumption, the inside concentration data was compared with the outside concentration data. The correlation of the data suggested that the inside concentrations were not a good predictor of the outside concentrations. This poor correlation was deemed to be a result of operational unknownsmore » within the structures.« less

  10. Modeling, Monitoring and Fault Diagnosis of Spacecraft Air Contaminants

    NASA Technical Reports Server (NTRS)

    Ramirez, W. Fred; Skliar, Mikhail; Narayan, Anand; Morgenthaler, George W.; Smith, Gerald J.

    1998-01-01

    Control of air contaminants is a crucial factor in the safety considerations of crewed space flight. Indoor air quality needs to be closely monitored during long range missions such as a Mars mission, and also on large complex space structures such as the International Space Station. This work mainly pertains to the detection and simulation of air contaminants in the space station, though much of the work is easily extended to buildings, and issues of ventilation systems. Here we propose a method with which to track the presence of contaminants using an accurate physical model, and also develop a robust procedure that would raise alarms when certain tolerance levels are exceeded. A part of this research concerns the modeling of air flow inside a spacecraft, and the consequent dispersal pattern of contaminants. Our objective is to also monitor the contaminants on-line, so we develop a state estimation procedure that makes use of the measurements from a sensor system and determines an optimal estimate of the contamination in the system as a function of time and space. The real-time optimal estimates in turn are used to detect faults in the system and also offer diagnoses as to their sources. This work is concerned with the monitoring of air contaminants aboard future generation spacecraft and seeks to satisfy NASA's requirements as outlined in their Strategic Plan document (Technology Development Requirements, 1996).

  11. Size and mercury concentration relationship as contamination index

    SciTech Connect

    Rincon, F.; Zurera, G.; Pozo-Lora, R.

    1987-03-01

    The possible relationship which exists between size (as weight or length) and mercury concentration in muscle is used by some authors as evidence of the degree of mercury contamination present in aquatic environments. In this study, the level of mercury contamination present in populations of red crayfish (Procambarus clarkii) and grey mullet (Liza ramada) of the Marshes of the River Guadalquivir, both of great interest as food in the Marshes surroundings, has been shown. At the same time, the validity of using the relationship between size (as weight or length) and mercury concentration in muscle, as evidence of the mercury contamination present in the aquatic environment investigated, is discussed.

  12. Relation of nickel concentrations in tree rings to groundwater contamination

    USGS Publications Warehouse

    Yanosky, Thomas M.; Vroblesky, Don A.

    1992-01-01

    Increment cores were collected from trees growing at two sites where groundwater is contaminated by nickel. Proton-induced X ray emission spectroscopy was used to determine the nickel concentrations in selected individual rings and in parts of individual rings. Ring nickel concentrations were interpreted on the basis of recent concentrations of nickel in aquifers, historical information about site use activities, and model simulations of groundwater flow. Nickel concentrations in rings increased during years of site use but not in trees outside the contaminated aquifers. Consequently, it was concluded that trees may preserve in their rings an annual record of nickel contamination in groundwater. Tulip trees and oaks contained higher concentrations of nickel than did sassafras, sweet gum, or black cherry. No evidence was found that nickel accumulates consistently within parts of individual rings or that nickel is translocated across ring boundaries.

  13. Relation of Nickel Concentrations in Tree Rings to Groundwater Contamination

    NASA Astrophysics Data System (ADS)

    Yanosky, Thomas M.; Vroblesky, Don A.

    1992-08-01

    Increment cores were collected from trees growing at two sites where groundwater is contaminated by nickel. Proton-induced X ray emission spectroscopy was used to determine the nickel concentrations in selected individual rings and in parts of individual rings. Ring nickel concentrations were interpreted on the basis of recent concentrations of nickel in aquifers, historical information about site use activities, and model simulations of groundwater flow. Nickel concentrations in rings increased during years of site use but not in trees outside the contaminated aquifers. Consequently, it was concluded that trees may preserve in their rings an annual record of nickel contamination in groundwater. Tulip trees and oaks contained higher concentrations of nickel than did sassafras, sweet gum, or black cherry. No evidence was found that nickel accumulates consistently within parts of individual rings or that nickel is translocated across ring boundaries.

  14. Scavenging ratios based on inflow air concentrations

    SciTech Connect

    Davis, W.E.; Dana, M.T.; Lee, R.N.; Slinn, W.G.N.; Thorp, J.M.

    1991-07-01

    Scavenging ratios were calculated from field measurements made during April 1985. Event precipitation samples were collected at the surface, but air chemistry measurements in the air mass feeding the precipitation were made from an aircraft. In contrast, ratios calculated in previous studies have used air concentration and precipitation chemistry data from only surface measurements. Average scavenging ratios were calculated for SO{sub 4}{sup 2{minus}}, NO{sub 3}{sup {minus}}, NH{sub 4}{sup +}, total sulfate, total nitrate, and total ammonium for 5 events; the geometric mean of these scavenging ratios were 8.5 {times} 10{sup 5}, 5.6 {times} 10{sup 6}, 4.3 {times} 10{sup 5}, 3.4 {times} 10{sup 5}, 2.4 {times} 10{sup 6}, and 9.7 {times} 10{sup 4}, respectively. These means are similar to but less variable than previous ratios formed using only surface data.

  15. Methods for Environments and Contaminants: Hazardous Air Pollutants

    EPA Pesticide Factsheets

    EPA’s Office of Air Quality Planning and Standards estimated census tract annual average outdoor concentrations of 181i hazardous air pollutants, also known as air toxics, as part of EPA’s National Air Toxics Assessment (NATA) for the calendar year 2005.

  16. Spacecraft maximum allowable concentrations for selected airborne contaminants, volume 1

    NASA Technical Reports Server (NTRS)

    1994-01-01

    As part of its efforts to promote safe conditions aboard spacecraft, NASA requested the National Research Council (NRC) to develop guidelines for establishing spacecraft maximum allowable concentrations (SMAC's) for contaminants, and to review SMAC's for various spacecraft contaminants to determine whether NASA's recommended exposure limits are consistent with the guidelines recommended by the subcommittee. In response to NASA's request, the NRC organized the Subcommittee on Guidelines for Developing Spacecraft Maximum Allowable Concentrations for Space Station Contaminants within the Committee on Toxicology (COT). In the first phase of its work, the subcommittee developed the criteria and methods for preparing SMAC's for spacecraft contaminants. The subcommittee's report, entitled Guidelines for Developing Spacecraft Maximum Allowable Concentrations for Space Station Contaminants, was published in 1992. The executive summary of that report is reprinted as Appendix A of this volume. In the second phase of the study, the Subcommittee on Spacecraft Maximum Allowable Concentrations reviewed reports prepared by NASA scientists and contractors recommending SMAC's for 35 spacecraft contaminants. The subcommittee sought to determine whether the SMAC reports were consistent with the 1992 guidelines. Appendix B of this volume contains the first 11 SMAC reports that have been reviewed for their application of the guidelines developed in the first phase of this activity and approved by the subcommittee.

  17. Wash-out of ambient air contaminations for breath measurements.

    PubMed

    Maurer, F; Wolf, A; Fink, T; Rittershofer, B; Heim, N; Volk, T; Baumbach, J I; Kreuer, S

    2014-06-01

    In breath analysis, ambient air contaminations are ubiquitous and difficult to eliminate. This study was designed to investigate the reduction of ambient air background by a lung wash-out with synthetic air. The reduction of the initial ambient air volatile organic compound (VOC) intensity was investigated in the breath of 20 volunteers inhaling synthetic air via a sealed full face mask in comparison to inhaling ambient air. Over a period of 30 minutes, breath analysis was conducted using ion mobility spectrometry coupled to a multi-capillary column. A total of 68 VOCs were identified for inhaling ambient air or inhaling synthetic air. By treatment with synthetic air, 39 VOCs decreased in intensity, whereas 29 increased in comparison to inhaling ambient air. In total, seven VOCs were significantly reduced (P-value < 0.05). A complete wash-out of VOCs in this setting was not observed, whereby a statistically significant reduction up to 65% as for terpinolene was achieved. Our setting successfully demonstrated a reduction of ambient air contaminations from the airways by a lung wash-out with synthetic air.

  18. Three-dimensional numerical simulation of air contamination dispersal in a room

    SciTech Connect

    Yaghoubi, M.A.; Knappmiller, K.D.; Kirkpatrick, A.T.

    1995-08-01

    A numerical study of air movement and contaminant transport is made to predict airflow patterns, ventilation performance, and indoor air quality in a typical office space. Both conventional cooling and cold-air-jet cooling methods are investigated. The space heat load is from a hot wall that creates a plume. This plume either opposes or aids the flow of the jet, depending on its location. The transient variation of room occupied zone average concentration is exponential after a change of the source strength equivalent to a change in the number of people in the room. The ventilation efficiency as well as the contaminant removal effectiveness of cold-jet cooling are nearly the same as those of conventional cooling. Turnover time for cold-air-jet cooling is about 52.8% higher than for conventional cooling when the hot plume aids the jet and 42.9% higher when it opposes the jet. The highest ventilation efficiency is {eta}{sub v} = 1.28 when the room is cooled with conventional-temperature supply air, the plume opposes the jet, and the contaminant source is located near the air return and the plume. The worst condition, {eta}{sub v} = 0.8, occurs when the air close to the pollutant source is stagnant. This happens for the room with cold-temperature supply air, an opposing plume, and a contamination source on the opposite side of the room from the return and the plume.

  19. Minanre Gas Concentrators For Air Sampling

    SciTech Connect

    Dr. Seung Ho Hong

    2001-03-01

    The goal of this project was to demonstrate the feasibility of a compact, lightweight, gas-sampling device with rapid-cycle-time characteristics. The highlights of our Phase I work include: (1) Demonstration of a compact gas sampler with integrated heater. This device has an order of magnitude greater adsorption capacity and much faster heating/cooling times than commercial sorbent tubes. (2) Completion of computational fluid dynamics modeling of the gas sampler to determine airflow characteristics for various design options. These modeling efforts guided the development and testing of the Mesochannel Gas Sampler prototype. (3) Testing of the Mesochannel Gas Sampler in parallel with tests of two packed-bed samplers. These tests showed the Mesochannel Gas Sampler represents a substantial improvement compared with the packed-bed approach. Our mesochannel heat-exchanger/adsorber architecture allows very efficient use of adsorbent mass, high adsorbent loadings, and very low pressure drop, which makes possible very high air-sampling rates using a simple, low-power fan. This device is well-suited for collecting samples of trace-level contaminants. The integrated heater, which forms the adsorbent-coated mesochannel walls, allows direct heating of the adsorbent and results in very rapid desorption of the adsorbed species. We believe the Mesochannel Gas Sampler represents a promising technology for the improvement of trace-contaminant detection limits. In our Phase II proposal, we outline several improvements to the gas sampler that will further improve its performance.

  20. Ground-water contamination at Wurtsmith Air Force Base, Michigan

    USGS Publications Warehouse

    Stark, J.R.; Cummings, T.R.; Twenter, F.R.

    1983-01-01

    A sand and gravel aquifer of glacial origin underlies Wurtsmith Air Force Base in northeastern lower Michigan. The aquifer overlies a thick clay layer at an average depth of 65 feet. The water table is about 10 feet below land surface in the western part of the Base and about 25 feet below land surface in the eastern part. A ground-water divide cuts diagonally across the Base from northwest to southeast. South of the divide, ground water flows to the Au Sable River; north of the divide, it flows to Van Etten Creek and Van Etten Lake. Mathematical models were used to aid in calculating rates of groundwater flow. Rates range from about 0.8 feet per day in the eastern part of the Base to about 0.3 feet per day in the western part. Models also were used as an aid in making decisions regarding purging of contaminated water from the aquifer. In 1977, trichloroethylene was detected in the Air Force Base water-supply system. It had leaked from a buried storage tank near Building 43 in the southeastern part of the Base and moved northeastward under the influence of the natural ground-water gradient and the pumping of Base water-supply wells. In the most highly contaminated part of the plume, concentrations are greater than 1,000 micrograms per liter. Current purge pumping is removing some of the trichloroethylene, and seems to have arrested its eastward movement. Pumping of additional purge wells could increase the rate of removal. Trichloroethylene has also been detected in ground water in the vicinity of the Base alert apron, where a plume from an unknown source extends northeastward off Base. A smaller, less well-defined area of contamination also occurs just north of the larger plume. Trichloroethylene, identified near the waste-treatment plant, seepage lagoons, and the northern landfill area, is related to activities and operations in these areas. Dichloroethylene and trichloroethylene occur in significant quantities westward of Building 43, upgradient from the major

  1. Air emissions from exposed contaminated sediments and dredged material

    SciTech Connect

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

    1999-01-01

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

  2. Effect of air-conditioner on fungal contamination

    NASA Astrophysics Data System (ADS)

    Hamada, Nobuo; Fujita, Tadao

    Air-conditioners (AC) produce much dew and wet conditions inside their apparatus, when in operation. We studied the fungal contamination in AC and found that the average fungal contamination of AC filters was about 5-fold greater than that of a carpet, and Cladosporium and Penicillium were predominant in AC filters. The fungal contamination inside AC, which were used everyday, increased more markedly than those not used daily, e.g. a few days per week or rarely. Moreover, the airborne fungal contamination in rooms during air-conditioning was about 2-fold greater than one in rooms without AC, and was highest when air-conditioning started and decreased gradually with time. We recognized that the airborne fungal contamination was controlled by the environmental condition of the rooms, in which AC were used. It is suggested that AC might promote mold allergies in users via airborne fungal spores derived from the AC. On the other hand, AC was estimated to remove moisture in the room atmosphere and carpets, and reduce the relative humidity in rooms. It was found that the average fungal contamination in the house dust of carpets with AC was suppressed by two-third of that in rooms without AC. The use of AC for suppressing fungal hazards was discussed.

  3. Spacecraft contamination programs within the Air Force Systems Command Laboratories

    NASA Technical Reports Server (NTRS)

    Murad, Edmond

    1990-01-01

    Spacecraft contamination programs exist in five independent AFSC organizations: Geophysics Laboratory (GL), Arnold Engineering and Development Center (AEDC), Rome Air Development Center (RADC/OSCE), Wright Research and Development Center (MLBT), Armament Laboratory (ATL/SAI), and Space Systems Division (SSD/OL-AW). In addition, a sizable program exists at Aerospace Corp. These programs are complementary, each effort addressing a specific area of expertise: GL's effort is aimed at addressing the effects of on-orbit contamination; AEDC's effort is aimed at ground simulation and measurement of optical contamination; RADC's effort addresses the accumulation, measurement, and removal of contamination on large optics; MLBT's effort is aimed at understanding the effect of contamination on materials; ATL's effort is aimed at understanding the effect of plume contamination on systems; SSD's effort is confined to the integration of some contamination experiments sponsored by SSD/CLT; and Aerospace Corp.'s effort is aimed at supporting the needs of the using System Program Offices (SPO) in specific areas, such as contamination during ground handling, ascent phase, laboratory measurements aimed at understanding on-orbit contamination, and mass loss and mass gain in on-orbit operations. These programs are described in some detail, with emphasis on GL's program.

  4. Use of passive sampling devices to determine soil contaminant concentrations

    SciTech Connect

    Johnson, K.A. |; Hooper, M.J.; Weisskopf, C.P.

    1996-12-31

    The effective remediation of contaminated sites requires accurate identification of chemical distributions. A rapid sampling method using passive sampling devices (PSDs) can provide a thorough site assessment. We have been pursuing their application in terrestrial systems and have found that they increase the ease and speed of analysis, decrease solvent usage and overall cost, and minimize the transport of contaminated soils. Time and cost savings allow a higher sampling frequency than is generally the case using traditional methods. PSDs have been used in the field in soils of varying physical properties and have been successful in estimating soil concentrations ranging from 1 {mu}g/kg (parts per billion) to greater than 200 mg/kg (parts per million). They were also helpful in identifying hot spots within the sites. Passive sampling devices show extreme promise as an analytical tool to rapidly characterize contaminant distributions in soil. There are substantial time and cost savings in laboratory personnel and supplies. By selectively excluding common interferences that require sample cleanup, PSDs can be retrieved from the field and processed rapidly (one technician can process approximately 90 PSDs in an 8-h work day). The results of our studies indicate that PSDs can be used to accurately estimate soil contaminant concentrations and provide lower detection limits. Further, time and cost savings will allow a more thorough and detailed characterization of contaminant distributions. 13 refs., 4 figs., 2 tabs.

  5. Analysis of industrial contaminants in indoor air. Part 2. Emergent contaminants and pesticides.

    PubMed

    Garcia-Jares, Carmen; Regueiro, Jorge; Barro, Ruth; Dagnac, Thierry; Llompart, Maria

    2009-01-16

    This article reviews recent literature on the analysis of several contaminants related to the industrial development in indoor air in the framework of the REACH project. In this second part, the attention is focused on emergent contaminants and biocides. Among these chemicals, phthalates, polybrominated and phosphate flame retardants, fragrances, pesticides, as well as other emerging pollutants, are increasing their environmental and health concern and are extensively found in indoor air. Some of them are suspected to behave as priority organic pollutants (POPs) and/or endocrine disrupting compounds (EDC), and can be found both in air and associated to the suspended particulate matter (PM) and settled dust. Main literature considered for this review is from the last ten years, reporting analytical developments and applications regarding the considered contaminants in the indoor environment. Sample collection and pretreatment, analyte extraction or desorption, clean-up procedures, determination techniques, and performance results are summarized and discussed.

  6. THE ALLERGENIC POTENTIAL OF INDOOR AIR FUNGAL CONTAMINANTS

    EPA Science Inventory


    The Allergenic Potential of Indoor Air Fungal Contaminants
    Marsha D W Ward1, Michael E Viana2, Yongjoo Chung3, Najwa Haykal-Coates1, Lisa B Copeland1, Steven H Gavett1, and MaryJane K Selgrade1. 1US EPA, ORD, NHEERL, RTP, NC, USA. 2NCSU, CVM, Raleigh, NC, USA, 3 UNC, SPH,...

  7. ASSESSING THE ALLERGIC POTENTIAL OF INDOOR AIR FUNGAL CONTAMINANTS

    EPA Science Inventory

    Assessing the Allergic Potential of Indoor Air Fungal Contaminants
    Marsha D W Ward1, Michael E Viana2, Yonjoo Chung3, Najwa Haykal-Coates1, Lisa B Copeland1, Steven H Gavett1, and MaryJane K Selgrade1. 1US EPA, ORD, NHEERL, RTP, NC, USA. 2NCSU, CVM, Raleigh, NC, USA, 3 UNC, S...

  8. Open air demolition of facilities highly contaminated with plutonium

    SciTech Connect

    Lloyd, E.R.; Lackey, M.B.; Stevens, J.M.; Zinsli, L.C.

    2007-07-01

    The demolition of highly contaminated plutonium buildings usually is a long and expensive process that involves decontaminating the building to near free- release standards and then using conventional methods to remove the structure. It doesn't, however, have to be that way. Fluor has torn down buildings highly contaminated with plutonium without excessive decontamination. By removing the select source term and fixing the remaining contamination on the walls, ceilings, floors, and equipment surfaces; open-air demolition is not only feasible, but it can be done cheaper, better (safer), and faster. Open-air demolition techniques were used to demolish two highly contaminated buildings to slab-on-grade. These facilities on the Department of Energy's Hanford Site were located in, or very near, compounds of operating nuclear facilities that housed hundreds of people working on a daily basis. To keep the facilities operating and the personnel safe, the projects had to be creative in demolishing the structures. Several key techniques were used to control contamination and keep it within the confines of the demolition area: spraying fixatives before demolition; applying fixative and misting with a fine spray of water as the buildings were being taken down; and demolishing the buildings in a controlled and methodical manner. In addition, detailed air-dispersion modeling was done to establish necessary building and meteorological conditions and to confirm the adequacy of the proposed methods. Both demolition projects were accomplished without any spread of contamination outside the modest buffer areas established for contamination control. Furthermore, personnel exposure to radiological and physical hazards was significantly reduced by using heavy equipment rather than 'hands on' techniques. (authors)

  9. OPEN AIR DEMOLITION OF FACILITIES HIGHLY CONTAMINATED WITH PLUTONIUM

    SciTech Connect

    LLOYD, E.R.

    2007-05-31

    The demolition of highly contaminated plutonium buildings usually is a long and expensive process that involves decontaminating the building to near free- release standards and then using conventional methods to remove the structure. It doesn't, however, have to be that way. Fluor has torn down buildings highly contaminated with plutonium without excessive decontamination. By removing the select source term and fixing the remaining contamination on the walls, ceilings, floors, and equipment surfaces; open-air demolition is not only feasible, but it can be done cheaper, better (safer), and faster. Open-air demolition techniques were used to demolish two highly contaminated buildings to slab-on-grade. These facilities on the Department of Energy's Hanford Site were located in, or very near, compounds of operating nuclear facilities that housed hundreds of people working on a daily basis. To keep the facilities operating and the personnel safe, the projects had to be creative in demolishing the structures. Several key techniques were used to control contamination and keep it within the confines of the demolition area: spraying fixatives before demolition; applying fixative and misting with a fine spray of water as the buildings were being taken down; and demolishing the buildings in a controlled and methodical manner. In addition, detailed air-dispersion modeling was done to establish necessary building and meteorological conditions and to confirm the adequacy of the proposed methods. Both demolition projects were accomplished without any spread of contamination outside the modest buffer areas established for contamination control. Furthermore, personnel exposure to radiological and physical hazards was significantly reduced by using heavy equipment rather than ''hands on'' techniques.

  10. Surface contamination artificially elevates initial sweat mineral concentrations.

    PubMed

    Ely, Matthew R; Kenefick, Robert W; Cheuvront, Samuel N; Chinevere, Troy D; Lacher, Craig P; Lukaski, Henry C; Montain, Scott J

    2011-06-01

    Several sweat mineral element concentrations decline with serial sampling. Possible causes include reduced dermal mineral concentrations or flushing of surface contamination. The purpose of this study was to simultaneously sample mineral concentrations in transdermal fluid (TDF), sweat, and serum during extended exercise-heat stress to determine if these compartments show the same serial changes during repeat sampling. Sixteen heat-acclimated individuals walked on a treadmill (1.56 m/s, 3.0% grade) in a 35°C, 20% relative humidity (RH), 1 m/s wind environment 50 min each hour for 3 h. Mineral concentrations of Ca, Cu, Fe, K, Mg, Na, and Zn were measured each hour from serum, sweat from upper back (sweat pouch) and arm (bag), and TDF from the upper back. Sites were meticulously cleaned to minimize surface contamination. Mineral concentrations were determined by spectrometry. TDF remained stable over time, with exception of a modest increase in TDF [Fe] (15%) and decrease in TDF [Zn] (-18%). Likewise, serum and pouch sweat samples were stable over time. In contrast, the initial arm bag sweat mineral concentrations were greater than those in the sweat pouch, and [Ca], [Cu], [Mg], and [Zn] declined 26-76% from initial to the subsequent samples, becoming similar to sweat pouch. Nominal TDF mineral shifts do not affect sweat mineral concentrations. Arm bag sweat mineral concentrations are initially elevated due to skin surface contaminants that are not removed despite meticulous cleaning (e.g., under fingernails, on arm hair), then decrease with extended sweating and approach those measured from the scapular region.

  11. Subsurface sediment contamination during borehole drilling with an air-actuated down-hole hammer.

    PubMed

    Malard, Florian; Datry, Thibault; Gibert, Janine

    2005-10-01

    Drilling methods can severely alter physical, chemical, and biological properties of aquifers, thereby influencing the reliability of water samples collected from groundwater monitoring wells. Because of their fast drilling rate, air-actuated hammers are increasingly used for the installation of groundwater monitoring wells in unconsolidated sediments. However, oil entrained in the air stream to lubricate the hammer-actuating device can contaminate subsurface sediments. Concentrations of total hydrocarbons, heavy metals (Cu, Ni, Cr, Zn, Pb, and Cd), and nutrients (particulate organic carbon, nitrogen, and phosphorus) were measured in continuous sediment cores recovered during the completion of a 26-m deep borehole drilled with a down-hole hammer in glaciofluvial deposits. Total hydrocarbons, Cu, Ni, Cr and particulate organic carbon (POC) were all measured at concentrations far exceeding background levels in most sediment cores. Hydrocarbon concentration averaged 124 +/- 118 mg kg(-1) dry sediment (n = 78 samples) with peaks at depths of 8, 14, and 20 m below the soil surface (maximum concentration: 606 mg kg(-1)). The concentrations of hydrocarbons, Cu, Ni, Cr, and POC were positively correlated and exhibited a highly irregular vertical pattern, that probably reflected variations in air loss within glaciofluvial deposits during drilling. Because the penetration of contaminated air into the formation is unpreventable, the representativeness of groundwater samples collected may be questioned. It is concluded that air percussion drilling has strong limitations for well installation in groundwater quality monitoring surveys.

  12. Indoor air condensate as a novel matrix for monitoring inhalable organic contaminants.

    PubMed

    Roll, Isaac B; Halden, Rolf U; Pycke, Benny F G

    2015-05-15

    With the population of developed nations spending nearly 90% of their time indoors, indoor air quality (IAQ) is a critical indicator of human health risks from inhalation of airborne contaminants. We present a novel approach for qualitative monitoring of IAQ through the collection and analysis of indoor air condensate discharged from heat exchangers of heating, ventilation, and air conditioning (HVAC) systems. Condensate samples were collected from six suburban homes and one business in Maricopa County, Arizona, concentrated via solid-phase extraction, analyzed for 10 endocrine disrupting chemicals (EDCs) by liquid chromatography-tandem mass spectrometry (LC-MS/MS), and screened for additional organic compounds by gas chromatography-mass spectrometry (GC-MS). All 10 EDCs were detected in at least one of the sampled buildings. More than 100 additional compounds were detected by GC-MS, of which 40 were tentatively identified using spectral database searches. Twelve compounds listed as designated chemicals for biomonitoring by the California Environmental Contaminant Biomonitoring Program were detected. Microfiltration of condensate samples prior to extraction had no discernable effect on contaminant concentration, suggesting that contaminants were freely dissolved or associated with inhalable, submicron particles. This study is the first to document the utility of HVAC condensate for the qualitative assessment of indoor air for pollutants.

  13. Long-memory property in air pollutant concentrations

    NASA Astrophysics Data System (ADS)

    Chelani, Asha

    2016-05-01

    In the present paper, long-memory in air pollutant concentrations is reviewed and outcome of the past studies is analyzed to provide the possible mechanism behind temporal evolution of air pollutant concentrations. It is observed that almost all the studies show air pollutant concentrations over time possess persistence up to a certain limit. Self-organized criticality of air pollution, multiplicative process of pollutant concentrations, and uniformity in emission sources leading to self-organized criticality are few of the phenomena behind the persistent property of air pollutant concentrations. The self-organized criticality of air pollution is linked to atmosphere's self-cleansing mechanism. This demonstrates that inspite of increasing anthropogenic emissions, self-organized criticality of air pollution is sustained and has low influence of human interventions. In the future, this property may, however, be perturbed due to continuous air pollution emissions, which may influence the accuracy in predictions.

  14. Air contamination with nitric oxide: effect on exhaled nitric oxide response.

    PubMed

    Therminarias, A; Flore, P; Favre-Juvin, A; Oddou, M F; Delaire, M; Grimbert, F

    1998-03-01

    This study examines the response of exhaled nitric oxide (NO) concentration (ECNO) and quantity of exhaled NO over time (EVNO) in 10 healthy subjects breathing into five polyethylene bags, one in which synthetic air was free of NO and four in which NO was diluted to concentrations of 20 +/- 0.6, 49 +/- 0.8, 98 +/- 2, and 148 +/- 2 ppb, respectively. Each subject was connected to each bag for 10 min at random. Minute ventilation and ECNO were measured continuously, and EVNO was calculated continuously. ECNO and EVNO values were significantly higher for an inhaled NO concentration of 20 ppb than for NO-free air. Above 20 ppb, ECNO and EVNO increased linearly with inhaled NO concentration. It is reasonable to assume that a share of the quantity of inspired NO over time (InspVNO) because of air contamination by pollution is rejected by the ventilatory pathway. Insofar as InspVNO does not affect endogenous production or the metabolic fate of NO in the airway, this share may be estimated as being approximately one third of InspVNO, the remainder being taken by the endogenous pathway. Thus, air contamination by the NO resulting from pollution greatly increases the NO response in exhaled air.

  15. Measurements of air contaminants during the Cerro Grande fire at Los Alamos National Laboratory

    SciTech Connect

    Eberhart, Craig

    2010-08-01

    Ambient air sampling for radioactive air contaminants was continued throughout the Cerro Grande fire that burned part of Los Alamos National Laboratory. During the fire, samples were collected more frequently than normal because buildup of smoke particles on the filters was decreasing the air flow. Overall, actual sampling time was 96% of the total possible sampling time for the May 2000 samples. To evaluate potential human exposure to air contaminants, the samples were analyzed as soon as possible and for additional specific radionuclides. Analyses showed that the smoke from the fire included resuspended radon decay products that had been accumulating for many years on the vegetation and the forest floor that burned. Concentrations of plutonium, americium, and depleted uranium were also measurable, but at locations and concentrations comparable to non-fire periods. A continuous particulate matter sampler measured concentrations that exceeded the National Ambient Air Quality Standard for PM-10 (particles less than 10 micrometers in diameter). These high concentrations were caused by smoke from the fire when it was close to the sampler.

  16. Estimation of contaminant subslab concentration in petroleum vapor intrusion.

    PubMed

    Yao, Yijun; Yang, Fangxing; Suuberg, Eric M; Provoost, Jeroen; Liu, Weiping

    2014-08-30

    In this study, the development and partial validation are presented for an analytical approximation method for prediction of subslab contaminant concentrations in PVI. The method involves combining an analytic approximation to soil vapor transport with a piecewise first-order biodegradation model (together called the Analytic Approximation Method, including Biodegradation, AAMB), the result of which calculation provides an estimate of contaminant subslab concentrations, independent of building operation conditions. Comparisons with three-dimensional (3-D) simulations and another PVI screening tool, BioVapor, show that the AAMB is suitable for application in a scenario involving a building with an impermeable foundation surrounded by open ground surface, where the atmosphere is regarded as the primary oxygen source. Predictions from the AAMB can be used to determine the required vertical source-building separation, given a subslab screening concentration, allowing identification of buildings at risk for PVI. This equation shows that the "vertical screening distance" suggested by U.S. EPA is sufficient in most cases, as long as the total petroleum hydrocarbon (TPH) soil gas concentration at the vapor source does not exceed 50-100mg/L. When the TPH soil gas concentration of the vapor source approaches a typical limit, i.e. 400mg/L, the "vertical screening distance" required would be much greater.

  17. Estimation of contaminant subslab concentration in petroleum vapor intrusion

    PubMed Central

    Yao, Yijun; Yang, Fangxing; Suuberg, Eric M.; Provoost, Jeroen; Liu, Weiping

    2015-01-01

    In this study, the development and partial validation are presented for an analytical approximation method for prediction of subslab contaminant concentrations in PVI. The method involves combining an analytic approximation to soil vapor transport with a piecewise first-order biodegradation model (together called the analytic approximation method, including biodegradation, AAMB), the result of which calculation provides an estimate of contaminant subslab concentrations, independent of building operation conditions. Comparisons with three-dimensional (3-D) simulations and another PVI screening tool, BioVapor, show that the AAMB is suitable for application in a scenario involving a building with an impermeable foundation surrounded by open ground surface, where the atmosphere is regarded as the primary oxygen source. Predictions from the AAMB can be used to determine the required vertical source-building separation, given a subslab screening concentration, allowing identification of buildings at risk for PVI. This equation shows that the “vertical screening distance” suggested by U.S. EPA is sufficient in most cases, as long as the total petroleum hydrocarbon (TPH) soil gas concentration at the vapor source does not exceed 50–100 mg/L. When the TPH soil gas concentration of the vapor source approaches a typical limit, i.e. 400 mg/L, the “vertical screening distance” required would be much greater. PMID:25124892

  18. Circumventing shallow air contamination in Mid Ocean Ridge Basalts

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, Sujoy; Parai, Rita; Tucker, Jonathan; Middleton, Jennifer; Langmuir, Charles

    2016-04-01

    Noble gases in mantle-derived basalts provide a rich portrait of mantle degassing and surface-interior volatile exchange. However, the ubiquity of shallow-level air contamination frequently obscures the mantle noble gas signal. In a majority of samples, shallow air contamination dominates the noble gas budget. As a result, reconstructing the variability in heavy noble gas mantle source compositions and inferring the history of deep recycling of atmospheric noble gases is difficult. For example, in the gas-rich popping rock 2ΠD43, 129Xe/130Xe ratios reach 7.7±0.23 in individual step-crushes, but the bulk composition of the sample is close to air (129Xe/130Xe of 6.7). Here, we present results from experiments designed to elucidate the source of shallow air contamination in MORBs. Step-crushes were carried out to measure He, Ne, Ar and Xe isotopic compositions on two aliquots of a depleted popping glass that was dredged from between the Kane and Atlantis Fracture Zones of the Mid-Atlantic Ridge in May 2012. One aliquot was sealed in ultrapure N2 after dredge retrieval, while the other aliquot was left exposed to air for 3.5 years. The bulk 20Ne/22Ne and 129Xe/130Xe ratios measured in the aliquot bottled in ultrapure N2 are 12.3 and 7.6, respectively, and are nearly identical to the estimated mantle source values. On the other hand, step crushes in the aliquot left exposed to air for several years show Ne isotopic compositions that are shifted towards air, with a bulk 20Ne/22Ne of 11.5; the bulk 129Xe/130Xe, however, was close to 7.6. These results indicate that lighter noble gases exchange more efficiently between the bubbles trapped in basalt glass and air, suggesting a diffusive or kinetic mechanism for the incorporation of the shallow air contamination. Importantly, in Ne-Ar or Ar-Xe space, step-crushes from the bottled aliquot display a trend that can be easily fit with a simple two-component hyperbolic mixing between mantle and atmosphere noble gases. Step

  19. A simplified method for correcting contaminant concentrations in eggs for moisture loss.

    USGS Publications Warehouse

    Heinz, Gary H.; Stebbins, Katherine R.; Klimstra, Jon D.; Hoffman, David J.

    2009-01-01

    We developed a simplified and highly accurate method for correcting contaminant concentrations in eggs for the moisture that is lost from an egg during incubation. To make the correction, one injects water into the air cell of the egg until overflowing. The amount of water injected corrects almost perfectly for the amount of water lost during incubation or when an egg is left in the nest and dehydrates and deteriorates over time. To validate the new method we weighed freshly laid chicken (Gallus gallus) eggs and then incubated sets of fertile and dead eggs for either 12 or 19 d. We then injected water into the air cells of these eggs and verified that the weights after water injection were almost identical to the weights of the eggs when they were fresh. The advantages of the new method are its speed, accuracy, and simplicity: It does not require the calculation of a correction factor that has to be applied to each contaminant residue.

  20. Regenerable Air Purification System for Gas-Phase Contaminant Control

    NASA Technical Reports Server (NTRS)

    Constantinescu, Ileana C.; Qi, Nan; LeVan, M. Douglas; Finn, Cory K.; Finn, John E.; Luna, Bernadette (Technical Monitor)

    2000-01-01

    A regenerable air purification system (RAPS) that uses water vapor to displace adsorbed contaminants from an. adsorbent column into a closed oxidation loop is under development through cooperative R&D between Vanderbilt University and NASA Ames Research Center. A unit based on this design can be used for removing trace gas-phase contaminants from spacecraft cabin air or from polluted process streams including incinerator exhaust. Recent work has focused on fabrication and operation of a RAPS breadboard at NASA Ames, and on measurement of adsorption isotherm data for several important organic compounds at Vanderbilt. These activities support the use and validation of RAPS modeling software also under development at Vanderbilt, which will in turn be used to construct a prototype system later in the project.

  1. Groundwater flow and contaminant transport modelling at an air weapons range

    NASA Astrophysics Data System (ADS)

    Bordeleau, Geneviève; Martel, Richard; Schäfer, Dirk; Ampleman, Guy; Thiboutot, Sonia

    2008-07-01

    Numerical modelling was done at the Cold Lake Air Weapons Range, Canada, to test whether the dissolved RDX and nitrate detected in groundwater come from the same sources, and to predict whether contamination poses a threat to the surface water receptors near the site. Military live fire training activities may indeed pose a risk of contamination to groundwater resources, however field investigations on military bases are quite recent, and little information is available on the long-term behaviour of munition residues related contaminants. Very limited information was available about the contaminant source zones, which were assigned based on our knowledge of current training activities. The RDX plume was well represented with the model, but the heterogeneous distribution of nitrate concentrations was more difficult to reproduce. It was nonetheless determined that both contaminants originate from the same areas. According to the model, both contaminants should reach the nearby river, but concentrations in the river should remain very low if the source zone concentration does not change. Finally, the model allowed the recommendation of a new location for the main bombing target, which would offer added protection to the river and the lake into which it flows.

  2. Microbial contamination of indoor air due to leakages from crawl space: a field study.

    PubMed

    Airaksinen, M; Pasanen, P; Kurnitski, J; Seppänen, O

    2004-02-01

    Mechanical exhaust ventilation system is typical in apartment buildings in Finland. In most buildings the base floor between the first floor apartments and crawl space is not air tight. As the apartments have lower pressure than the crawl space due to ventilation, contaminated air may flow from the crawl space to the apartments. The object of this study was to find out whether a potential air flow from crawl space has an influence on the indoor air quality. The results show that in most cases the concentration of fungal spores was clearly higher in the crawl space than inside the building. The size distribution of fungal spores depended on the fungal species. Correlation between the fungal spores in the crawl space and indoors varied with microbial species. Some species have sources inside the building, which confounds the possible relation between crawl pace and indoor concentrations. Some species, such as Acremonium, do not normally have a source indoors, but its concentration in the crawl space was elevated; our measurements showed also elevated concentrations of Acremonium in the air of the apartments. This consistent finding shows a clear linkage between fungal spores in the indoor air and crawl space. We conclude that a building with a crawl space and pressure difference over the base floor could be a potential risk for indoor air quality in the first floor apartments.

  3. Numerical Study of Contaminant Effects on Combustion of Hydrogen, Ethane, and Methane in Air

    NASA Technical Reports Server (NTRS)

    Lai, H. T.; Thomas, S. R.

    1995-01-01

    A numerical study was performed to assess the effects of vitiated air on the chemical kinetics of hydrogen, ethane, and methane combustion with air. A series of calculations in static reacting systems was performed, where the initial temperature was specified and reactions occurred at constant pressure. Three different types of test flow contaminants were considered: NP, H2O, and a combustion of H2O and CO2. These contaminants are present in the test flows of facilities used for hypersonic propulsion testing. The results were computed using a detailed reaction mechanism and are presented in terms of ignition and reaction times. Calculations were made for a wide range of contaminant concentrations, temperatures and pressures. The results indicate a pronounced kinetic effect over a range of temperatures, especially with NO contamination and, to a lesser degree, with H2O contamination. In all cases studied, CO2 remained kinetically inert, but had a thermodynamic effect on results by acting as a third body. The largest effect is observed with combustion using hydrogen fuel, less effect is seen with combustion of ethane, and little effect of contaminants is shown with methane combustion.

  4. Concentrated Solar Air Conditioning for Buildings Project

    NASA Technical Reports Server (NTRS)

    McLaughlin, Rusty

    2010-01-01

    This slide presentation reviews project to implement the use of solar power to provide air conditioning for NASA buildings. Included is an overall conceptual schematic, and an diagram of the plumbing and instrumentation for the project. The use of solar power to power air conditioning in buildings, particularly in the Southwest, could save a significant amount of money. DOD studies have concluded that air conditioning accounts for 30-60% of total energy expenditures.

  5. Assessing atmospheric concentration of polychlorinated biphenyls by evergreen Rhododendron maximum next to a contaminated stream.

    PubMed

    Dang, Viet D; Walters, David M; Lee, Cindy M

    2016-09-01

    Conifers are often used as an air passive sampler, but few studies have focused on the implication of broadleaf evergreens to monitor atmospheric semivolatile organic compounds such as polychlorinated biphenyls (PCBs). In the present study, the authors used Rhododendron maximum (rhododendron) growing next to a contaminated stream to assess atmospheric PCB concentrations. The present study area was located in a rural setting and approximately 2 km downstream of a former capacitor plant. Leaves from the same mature shrubs were collected in late fall 2010 and winter and spring 2011. Polychlorinated biphenyls were detected in the collected leaves, suggesting that rhododendron can be used as air passive samplers in rural areas where active sampling is impractical. Estimated ΣPCB (47 congeners) concentrations in the atmosphere decreased from fall 2010 to spring 2011 with concentration means at 3990 pg m(-3) , 2850 pg m(-3) , and 931 pg m(-3) in fall 2010, winter 2011, and spring 2011, respectively. These results indicate that the atmospheric concentrations at this location continue to be high despite termination of active discharge from the former industrial source. Leaves had a consistent pattern of high concentrations of tetra-CBs and penta-CBs similar to the congener distribution in polyethylene passive samplers deployed in the water column, suggesting that volatilized PCBs from the stream were the primary source of contaminants in rhododendron leaves. Environ Toxicol Chem 2016;35:2192-2198. © 2016 SETAC.

  6. Assessing atmospheric concentration of polychlorinated biphenyls (PCBs) by evergreen Rhododendron maximum next to a contaminated stream

    USGS Publications Warehouse

    Dang, Viet D.; Walters, David; Lee, Cindy M.

    2016-01-01

    Conifers are often used as an “air passive sampler”, but few studies have focused on the implication of broadleaf evergreens to monitor atmospheric semivolatile organic compounds such as polychlorinated biphenyls (PCBs). In this study, we used Rhododendron maximum (rhododendron) growing next to a contaminated stream to assess atmospheric PCB concentrations. The study area was located in a rural setting and approximately 2 km downstream of a former Sangamo-Weston (S-W) plant. Leaves from the same mature shrubs were collected in late fall 2010, and winter and spring 2011. PCBs were detected in the collected leaves suggesting that rhododendron can be used as air passive samplers in rural areas where active sampling is impractical. Estimated ΣPCB (47 congeners) concentrations in the atmosphere decreased from fall 2010 to spring 2011 with concentration means at 3990, 2850, and 931 pg m-3 in fall 2010, winter 2011, and spring 2011, respectively. These results indicate that the atmospheric concentrations at this location continue to be high despite termination of active discharge from the former S-W plant. Leaves had a consistent pattern of high concentrations of tetra- and penta-CBs similar to the congener distribution in polyethylene (PE) passive samplers deployed in the water column suggesting that volatilized PCBs from the stream were the primary source of contaminants in rhododendron leaves.

  7. Modelling the impact of room temperature on concentrations of polychlorinated biphenyls (PCBs) in indoor air.

    PubMed

    Lyng, Nadja Lynge; Clausen, Per Axel; Lundsgaard, Claus; Andersen, Helle Vibeke

    2016-02-01

    Buildings contaminated with polychlorinated biphenyls (PCBs) are a health concern for the building occupants. Inhalation exposure is linked to indoor air concentrations of PCBs, which are known to be affected by indoor temperatures. In this study, a highly PCB contaminated room was heated to six temperature levels between 20 and 30 C, i.e. within the normal fluctuation of indoor temperatures, while the air exchange rate was constant. The steady-state air concentrations of seven PCBs were determined at each temperature level. A model based on Clausius-Clapeyron equation, ln(P) = -ΔH/RT + a(0), where changes in steady-state air concentrations in relation to temperature, was tested. The model was valid for PCB-28, PCB-52 and PCB-101; the four other congeners were sporadic or non-detected. For each congener, the model described a large proportion (R(2)>94%) of the variation in indoor air PCB levels. The results showed that one measured concentration of PCB at a known steady-state temperature can be used to predict the steady-state concentrations at other temperatures under circumstances where e.g. direct sunlight does not influence temperatures and the air exchange rate is constant. The model was also tested on field data from a PCB remediation case in an apartment in another contaminated building complex where PCB concentrations and temperature were measured simultaneously and regularly throughout one year. The model fitted relatively well with the regression of measured PCB air concentrations, ln(P) vs. 1/T, at varying temperature between 16.3 and 28.2 °C, even though the measurements were carried out under uncontrolled environmental condition.

  8. Do plants reflect atmospheric concentrations of persistent organic contaminants?

    SciTech Connect

    Jones, K.C.

    1994-12-31

    Chemical analysis of several types of plants -- such as pine needles, lichens, mosses and grasses -- has been used by numerous workers as a means of inferring spatial and temporal variations in the atmospheric concentrations of persistent organic compounds (e.g. PCBs, PAHs, CBs and PCDD/Fs). This is usually because plants are perceived as convenient `passive` air samplers and assumed to `integrate` variations in ambient concentrations during their lifetime. More recently, various researchers have sought to understand the mechanisms of exchange/uptake at the air vegetation surface, with a view to refining the use of vegetation sampling techniques and understanding the role of vegetation in influencing the global cycling of these compounds. This presentation will review some of the recent advances in this area, highlighting some of pitfalls and beneficial uses of employing plants as `monitoring tools`.

  9. Forced-air warming: a source of airborne contamination in the operating room?

    PubMed

    Albrecht, Mark; Gauthier, Robert; Leaper, David

    2009-10-10

    Forced-air-warming (FAW) is an effective and widely used means for maintaining surgical normothermia, but FAW also has the potential to generate and mobilize airborne contamination in the operating room.We measured the emission of viable and non-viable forms of airborne contamination from an arbitrary selection of FAW blowers (n=25) in the operating room. A laser particle counter measured particulate concentrations of the air near the intake filter and in the distal hose airstream. Filtration efficiency was calculated as the reduction in particulate concentration in the distal hose airstream relative to that of the intake. Microbial colonization of the FAW blower's internal hose surfaces was assessed by culturing the microorganisms recovered through swabbing (n=17) and rinsing (n=9) techniques.Particle counting revealed that 24% of FAW blowers were emitting significant levels of internally generated airborne contamination in the 0.5 to 5.0 µm size range, evidenced by a steep decrease in FAW blower filtration efficiency for particles 0.5 to 5.0 µm in size. The particle size-range-specific reduction in efficiency could not be explained by the filtration properties of the intake filter. Instead, the reduction was found to be caused by size-range-specific particle generation within the FAW blowers. Microorganisms were detected on the internal air path surfaces of 94% of FAW blowers.The design of FAW blowers was found to be questionable for preventing the build-up of internal contamination and the emission of airborne contamination into the operating room. Although we did not evaluate the link between FAW and surgical site infection rates, a significant percentage of FAW blowers with positive microbial cultures were emitting internally generated airborne contamination within the size range of free floating bacteria and fungi (<4 µm) that could, conceivably, settle onto the surgical site.

  10. Effects of H2O, CO2, and N2 air contaminants on critical airside strain rates for extinction of hydrogen-air counterflow diffusion flames

    NASA Technical Reports Server (NTRS)

    Pellett, G. L.; Northam, G. B.; Wilson, L. G.; Guerra, Rosemary

    1989-01-01

    Dish-shaped counterflow diffusion flames centered by opposing laminar jets of H2 and clean and contaminant O2/N2 mixtures in an argon bath at 1 atm were used to study the effects of contaminants on critical airside strain. The jet velocities for both flame extinction and restoration are found for a wide range of contaminant and O2 concentrations in the air jet. The tests are also conducted for a variety of input H2 concentrations. The results are compared with those from several other studies.

  11. Air Monitoring Leads to Discovery of New Contamination at Radioactive Waste Disposal Site (Area G) at LANL

    SciTech Connect

    Kraig, D.H.; Conrad, R.C.

    1999-06-08

    Air monitoring at Area G, the low-level radioactive waste disposal area at Los Alamos National Laboratory, revealed increased air concentrations of {sup 239}Pu and {sup 241}Am at one location along the north boundary. This air monitoring location is a couple of meters north of a dirt road used to access the easternmost part of Area G. Air concentrations of {sup 238}Pu were essentially unaffected, which was puzzling because the {sup 238}Pu and {sup 239}Pu are present in the local, slightly contaminated soils. Air concentrations of these radionuclides increased about a factor of ten in early 1995 and remained at those levels until the first quarter of 1996. During the spring of 1996 air concentrations again increased by a factor of about ten. No other radionuclides were elevated and no other Area G stations showed elevations of these radionuclides. After several formal meetings didn't provide an adequate cause for the elevations, a gamma survey was performed and showed a small area of significant contamination just south of the monitor location. We found in February, 1995, a trench for a water line had been dug within a meter of so of the air stations. Then, during early 1996, the dirt road was rerouted such that its new path was directly over the unknown contamination. It appears that the trenching brought contaminated material to the surface and caused the first rise in air concentrations and then the rerouting of the road over the contamination caused the second rise, during 1996. We also found that during 1976 and 1977 contaminated soils from the clean-up of an old processing facility had been spread over the filled pits in the vicinity of the air monitors. These soils were very low in 238Pu which explains why we saw very little {sup 238}Pu in the increased air concentrations. A layer of gravel and sand was spread over the contaminated area. Although air concentrations of {sup 239}Pu and {sup 241}Am dropped considerably, the y have not returned to pre-1995 levels.

  12. Monitor of the concentration of particles of dense radioactive materials in a stream of air

    DOEpatents

    Yule, Thomas J.

    1979-01-01

    A monitor of the concentration of particles of radioactive materials such as plutonium oxide in diameters as small as 1/2 micron includes in combination a first stage comprising a plurality of virtual impactors, a second stage comprising a further plurality of virtual impactors, a collector for concentrating particulate material, a radiation detector disposed near the collector to respond to radiation from collected material and means for moving a stream of air, possibly containing particulate contaminants, through the apparatus.

  13. Genesis Concentrator Target Particle Contamination Mapping and Material Identification

    NASA Technical Reports Server (NTRS)

    Calaway, Michael J.; Rodriquez, M. C.; Allton, J. H.

    2007-01-01

    The majority of surface particles were found to be < 5 microns in diameter with increasing numbers close to the optical resolution limit of 0.3 microns. Acceleration grid EDS results show that the majority of materials appear to be from the SRC shell and SLA materials which include carbon-carbon fibers and Si-rich microspheres in a possible silicone binder. Other major debris material from the SRC included white paint, kapton, collector array fragments, and Al. Image analysis also revealed that SRC materials were also found mixed with the Utah mud and salt deposits. The EDS analysis of the acceleration grid showed that particles < 1 m where generally carbon based particles. Chemical cleaning techniques with Xylene and HF in an ultrasonic bath are currently being investigated for removal of small particles by the Genesis science team as well as ultra-pure water megasonic cleaning by the JSC team [4]. Removal of organic contamination from target materials is also being investigated by the science team with the use of UV-ozone cleaning devices at JSC and Open University [5]. In preparation for solar wind oxygen analyses at UCLA and Open University [1, 2], surface particle contamination on three Genesis concentrator targets was closely examined to evaluate cleaning strategies. Two silicon carbide (Genesis sample # 60001 and 60003) and one chemical vapor deposited (CVD) 13C concentrator target (60002) were imaged and mosaic mapped with optical microscopes. The resulting full target mosaic images and particle feature maps were subsequently compared with non-flight, but flight-like, concentrator targets and sample return capsule (SRC) materials. Contamination found on the flown concentrator acceleration grid was further examined using a scanning electron microscope (SEM). Energy dispersive X-ray spectroscopy (EDS) for particle identification was subsequently compared with the optical images from the flown targets. Figure 1 show that all three targets imaged in this report

  14. Indoor air polychlorinated biphenyl concentrations in three communities along the Upper Hudson River, New York.

    PubMed

    Wilson, Lloyd R; Palmer, Patrick M; Belanger, Erin E; Cayo, Michael R; Durocher, Lorie A; Hwang, Syni-An A; Fitzgerald, Edward F

    2011-10-01

    Indoor air polychlorinated biphenyl (PCB) concentrations were measured in upstate New York as part of a nonoccupational exposure investigation. The adjacent study communities contain numerous sites of current and former PCB contamination, including two capacitor-manufacturing facilities. Indoor air PCB concentrations in the study area homes were not significantly different than in the comparison area homes. Total PCB concentrations in the study area homes ranged from 0.3 to 114.3 ng/m(3) (median 7.9). For the comparison area homes, concentrations ranged from 0.3 to 233.3 ng/m(3) (median 6.8). No correlations were found between PCB concentrations in indoor and outdoor air, with indoor concentrations generally 20 times higher than outdoor concentrations. Of the home characteristics cataloged, the presence of fluorescent lights was significantly associated with total PCB concentration in the study area only. The indoor PCB concentrations measured in this study are similar to those in other communities with known PCB-contaminated sites and similar to levels reported in other locations from the northeastern United States.

  15. Effects of contaminants on reproductive success of aquatic birds nesting at Edwards Air Force Base, California

    USGS Publications Warehouse

    Hothem, R.L.; Crayon, J.J.; Law, M.A.

    2006-01-01

    Contamination by organochlorine pesticides (OCs), polychlorinated biphenyls, metals, and trace elements at Edwards Air Force Base (EAFB), located in the Mojave Desert, could adversely affect nesting aquatic birds, especially at the sewage lagoons that comprise Piute Ponds. Estimates of avian reproduction, in conjunction with analyses of eggs and avian foods for contaminant residues, may indicate the potential for negative effects on avian populations. From 1996 to 1999, we conducted studies at the Piute Ponds area of EAFB to evaluate the impacts of contaminants on nesting birds. Avian reproduction was evaluated in 1999. Eggs were collected for chemical analyses in 1996 and 1999, and African clawed frogs (Xenopus laevis), a likely food source, were collected for chemical analyses in 1998. Avian species occupying the higher trophic levels-black-crowned night-heron (Nycticorax nycticorax), white-faced ibis (Plegadis chihi), and American avocet (Recurvirostra americana)-generally bioaccumulated higher concentrations of contaminants in their eggs. Reproductive success and egg hatchability of night-herons and white-faced ibises in the Piute Ponds were similar to results observed at other western colonies. Deformities were observed in only one embryo in this study, but concentrations of contaminants evaluated in this ibis embryo were considered insufficient to have caused the deformities. Because clawed frogs, a primary prey item for night-herons at Piute Ponds, had no detectable levels of any OCs, it is likely that OCs found in night-heron eggs were acquired from the wintering grounds rather than from EAFB. The presence of isomers of dichlorodiphenyltrichloroethane (DDT) in ibis eggs indicated recent exposure, but invertebrates used for food by ibises were not sampled at Piute Ponds, and conclusions about the source of OCs in ibis eggs could not be made. Concentrations of contaminants in random and failed eggs of individual species were not different, and we concluded

  16. Effects of contaminants on reproductive success of aquatic birds nesting at Edwards Air Force Base, California.

    PubMed

    Hothem, R L; Crayon, J J; Law, M A

    2006-11-01

    Contamination by organochlorine pesticides (OCs), polychlorinated biphenyls, metals, and trace elements at Edwards Air Force Base (EAFB), located in the Mojave Desert, could adversely affect nesting aquatic birds, especially at the sewage lagoons that comprise Piute Ponds. Estimates of avian reproduction, in conjunction with analyses of eggs and avian foods for contaminant residues, may indicate the potential for negative effects on avian populations. From 1996 to 1999, we conducted studies at the Piute Ponds area of EAFB to evaluate the impacts of contaminants on nesting birds. Avian reproduction was evaluated in 1999. Eggs were collected for chemical analyses in 1996 and 1999, and African clawed frogs (Xenopus laevis), a likely food source, were collected for chemical analyses in 1998. Avian species occupying the higher trophic levels--black-crowned night-heron (Nycticorax nycticorax), white-faced ibis (Plegadis chihi), and American avocet (Recurvirostra americana)--generally bioaccumulated higher concentrations of contaminants in their eggs. Reproductive success and egg hatchability of night-herons and white-faced ibises in the Piute Ponds were similar to results observed at other western colonies. Deformities were observed in only one embryo in this study, but concentrations of contaminants evaluated in this ibis embryo were considered insufficient to have caused the deformities. Because clawed frogs, a primary prey item for night-herons at Piute Ponds, had no detectable levels of any OCs, it is likely that OCs found in night-heron eggs were acquired from the wintering grounds rather than from EAFB. The presence of isomers of dichlorodiphenyltrichloroethane (DDT) in ibis eggs indicated recent exposure, but invertebrates used for food by ibises were not sampled at Piute Ponds, and conclusions about the source of OCs in ibis eggs could not be made. Concentrations of contaminants in random and failed eggs of individual species were not different, and we concluded

  17. 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

  18. Sex differences in contaminant concentrations of fish: a synthesis

    USGS Publications Warehouse

    Madenjian, Charles P.; Rediske, Richard R.; Krabbenhoft, David P.; Stapanian, Martin A.; Chernyak, Sergei M.; O'Keefe, James P.

    2016-01-01

    Comparison of whole-fish polychlorinated biphenyl (PCB) and total mercury (Hg) concentrations in mature males with those in mature females may provide insights into sex differences in behavior, metabolism, and other physiological processes. In eight species of fish, we observed that males exceeded females in whole-fish PCB concentration by 17 to 43%. Based on results from hypothesis testing, we concluded that these sex differences were most likely primarily driven by a higher rate of energy expenditure, stemming from higher resting metabolic rate (or standard metabolic rate (SMR)) and higher swimming activity, in males compared with females. A higher rate of energy expenditure led to a higher rate of food consumption, which, in turn, resulted in a higher rate of PCB accumulation. For two fish species, the growth dilution effect also made a substantial contribution to the sex difference in PCB concentrations, although the higher energy expenditure rate for males was still the primary driver. Hg concentration data were available for five of the eight species. For four of these five species, the ratio of PCB concentration in males to PCB concentration in females was substantially greater than the ratio of Hg concentration in males to Hg concentration in females. In sea lamprey (Petromyzon marinus), a very primitive fish, the two ratios were nearly identical. The most plausible explanation for this pattern was that certain androgens, such as testosterone and 11-ketotestosterone, enhanced Hg-elimination rate in males. In contrast, long-term elimination of PCBs is negligible for both sexes. According to this explanation, males ingest Hg at a higher rate than females, but also eliminate Hg at a higher rate than females, in fish species other than sea lamprey. Male sea lamprey do not possess either of the above-specified androgens. These apparent sex differences in SMRs, activities, and Hg-elimination rates in teleost fishes may also apply, to some degree, to higher

  19. Measuring Concentrations of Particulate 140La in the Air

    DOE PAGES

    Okada, Colin E.; Kernan, Warnick; Keillor, Martin; ...

    2016-01-01

    This article discusses deployment of air-samplers to measure the concentration of radioactive material in the air during the Full-Scale Radiological Dispersal Device experiments. Positioned 100-600 meters downwind of the release point, the filters were collected immediately and analyzed in a field laboratory. The article discusses quantities for total activity collected on the air filters as well as additional information to compute the average or integrated air concentrations. In the case of a public emergency, this type of information would be important for decision makers and responders.

  20. Contamination mechanisms of air basin with tritium in venues of underground nuclear explosions at the former Semipalatinsk test site.

    PubMed

    Lyakhova, O N; Lukashenko, S N; Larionova, N V; Tur, Y S

    2012-11-01

    During the period of testing from 1945 to 1962 at the territory of Semipalatinsk test site (STS) within the Degelen Mountains in tunnels, 209 underground nuclear explosions were produced. Many of the tunnels have seasonal water seepage in the form of streams, through which tritium migrates from the underground nuclear explosion (UNE) venues towards the surface. The issue of tritium contamination occupies a special place in the radioactive contamination of the environment. In this paper we assess the level and distribution of tritium in the atmospheric air of ecosystems with water seepage at tunnels № 176 and № 177, located on "Degelen" site. There has been presented general nature of tritium distribution in the atmosphere relative to surface of a watercourse which has been contaminated with tritium. The basic mechanisms were studied for tritium distribution in the air of studied ecosystems, namely, the distribution of tritium in the systems: water-atmosphere, tunnel air-atmosphere, soil water-atmosphere, vegetation-atmosphere. An analytical calculation of tritium concentration in the atmosphere by the concentration of tritium in water has been performed. There has experimentally obtained the dependence for predictive assessment of tritium concentrations in air as a function of tritium concentration in one of the inlet sources such as water, tunnel air, soil water, vegetation, etc.. The paper also describes the general nature of tritium distribution in the air in the area "Degelen".

  1. 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.

  2. Outdoor air PCB concentrations in three communities along the Upper Hudson River, New York.

    PubMed

    Palmer, Patrick M; Belanger, Erin E; Wilson, Lloyd R; Hwang, Syni-An A; Narang, Rajinder S; Gomez, Marta I; Cayo, Michael R; Durocher, Lorie A; Fitzgerald, Edward F

    2008-04-01

    Outdoor air polychlorinated biphenyl (PCB) concentrations were measured in upstate New York as part of a nonoccupational exposure investigation. The adjacent study communities of Hudson Falls and Fort Edward contain numerous sites of current and former PCB contamination, including two capacitor-manufacturing facilities. Outdoor air PCB concentrations in the study municipalities were significantly higher than in the comparison municipality of Glens Falls. Total PCB concentrations in the study area ranged from 0.102 to 4.011 ng/m(3) (median: 0.711 ng/m(3)). For the comparison area, concentrations ranged from 0.080 to 2.366 ng/m(3) (median: 0.431 ng/m(3)). Although our sampling was not designed to identify point sources, the presence of PCB-contaminated sites in the study area likely contributed to this observed difference in concentration. While elevated relative to the comparison area, total PCB concentrations in the study area are lower than those in other communities with known PCB-contaminated sites, and similar to levels reported in other locations from the northeastern United States.

  3. Assessment of ground-water contamination at Wurtsmith Air Force Base, Michigan, 1982-85

    USGS Publications Warehouse

    Cummings, T.R.; Twenter, F.R.

    1986-01-01

    Continued study of ground-water contamination at Wurtsmith Air Force Base, Michigan, defined the movement and distribution of volatile organic compounds in the glacial sand and gravel aquifer at known sites of contamination, and has defined new plumes at two other sites. The Arrow Street purge system, installed in 1982 to remove contaminants from the Building 43 plume, has lowered concentrations of trichloroethylene in ground water in the central part of the most contaminated area from a range of 1,000 to 2,000 micrograms per liter to about 200 micrograms per liter. Trichloroethylene is not escaping off-Base from this area. In the southern part of the Base a plume containing principally trichloroethylene and dichloroethylene has been delineated along Mission Drive. Maximum concentrations observed were 5,290 micrograms per liter of trichloroethylene and 1,480 micrograms per liter of dichloroethylene. Hydrologically suitable sites for purge wells are identified in the southern part of the plume using a new ground-water flow model of the Base. A benzene plume near the bulk-fuel storage area, delineated in earlier work, lias shifted to a more northerly direction under influence of the Arrow Street purge system. Sites initially identified for purging the benzene plume have been repositioned because of the change in contaminant movement. JP-4 fuel was found to be accumulating in wells near the bulk-fuel storage area, largely in response to seasonal fluctuations in the water table. It is thought to originate from a spill that occurred several years ago. A more thorough definition of contaminants in the northern landfill area has permitted a determination of the most hydrologically suitable sites for purge wells. In general, Concentrations found in water do not differ greatly from those observed in 1981. Since 1981, concentrations of trichloroethylene have decreased significantly in the Alert Apron plume. Near the origin of the plume, the concentration of trichloroethylene

  4. Biological air contamination in elderly care centers: geria project.

    PubMed

    Aguiar, Lívia; Mendes, Ana; Pereira, Cristiana; Neves, Paula; Mendes, Diana; Teixeira, João Paulo

    2014-01-01

    Indoor air quality (IAQ) affects health particularly in susceptible individuals such as the elderly. It has been estimated that the older population spends approximately 19-20 h/d indoors, and the majority of the elderly spend all of their time indoors in elderly care centers (ECC). Older individuals may be particularly at risk of exposure to detrimental effects from pollutants, even at low concentrations, due to common and multiple underlying chronic diseases that increase susceptibility. This study, aimed to assess the impact of indoor biological agents in 22 ECC located in Porto, was conducted during summer and winter from November 2011 to August 2013 at a total of 141 areas within dining rooms, drawing rooms, medical offices, and bedrooms (including the bedridden). Air sampling was carried out with a microbiological air sampler (Merck MAS-100) and using tryptic soy agar for bacteria and malt extract agar for fungi. The results obtained were compared with the recently revised Portuguese standards. In winter, mean fungi concentration exceeded reference values, while bacteria concentrations were within the new standards in both seasons. The main fungi species found indoors were Cladosporium (73%) in summer and Penicillium (67%) in winter. Aspergillus fumigatus, Aspergillus niger, and Aspergillus flavus, known potential pathogenic/toxigenic species, were also identified. Although the overall rate and mean values of bacteria and fungi found in ECC indoor air met Portuguese legislation, some concern is raised by the presence of pathogenic microorganisms. Simple measures, like opening windows and doors to promote air exchange and renewal, may improve effectiveness in enhancing IAQ.

  5. Microbiological evaluation of a newly designed dental air-turbine handpiece for anti-cross contaminations.

    PubMed

    Ohsuka, S; Ohta, M; Masuda, K; Kaneda, T; Ueda, M

    1994-01-01

    The effectiveness of a newly developed anti-cross contamination device for a dental air-turbine handpiece was tested. The handpiece with or without the anti-cross contamination device was contaminated with two bacterial strains, Staphylococcus aureus and Streptococcus mutans, as well as two bacteriophage strains, T2 and MS2. After contamination with these microorganisms, the handpieces were disinfected with glutaraldehyde or replaced with newly autoclaved ones. Residual microorganisms inside the handpiece or an air/water supply hose line were collected and counted after overnight cultivation. The anti-cross contamination device effectively reduced the contamination level of an air-turbine handpiece to that of the negative control. No microbial contamination in the air/water supply hose line was detected with this device.

  6. 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...

  7. 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.

  8. Background concentrations of 18 air toxics for North America.

    PubMed

    McCarthy, Michael C; Hafner, Hilary R; Montzka, Stephen A

    2006-01-01

    The U.S. Clean Air Act identifies 188 hazardous air pollutants (HAPs), or "air toxics," associated with adverse human health effects. Of these air toxics, 18 were targeted as the most important in a 10-City Pilot Study conducted in 2001 and 2002 as part of the National Air Toxics Trend Sites Program. In the present analysis, measurements available from monitoring networks in North America were used to estimate boundary layer background concentrations and trends of these 18 HAPs. The background concentrations reported in this study are as much as 85% lower than those reported in recent studies of HAP concentrations. Background concentrations of some volatile organic compounds were analyzed for trends at the 95% confidence level; only carbon tetrachloride (CCI4) and tetrachloroethylene decreased significantly in recent years. Remote background concentrations were compared with the one-in-a-million (i.e., 10(6)) cancer benchmarks to determine the possible causes of health risk in rural and remote areas; benzene, chloroform, formaldehyde, and chromium (Cr) fine particulate were higher than cancer benchmark values. In addition, remote background concentrations were found to contribute between 5% and 99% of median urban concentrations.

  9. Numerical Assessment of Indoor Air Exposure Risk from Subsurface NAPL Contamination under Hydrologic Uncertainties

    NASA Astrophysics Data System (ADS)

    Unger, A.; Yu, S.

    2007-12-01

    Understanding the risk of indoor air exposure to residual contaminants in the subsurface following the redevelopment of contaminated land redevelopment project is a central issue at many brownfield sites. In this study, we examine various mechanisms controlling vapor phase intrusion into the indoor air of a typical residential dwelling from a NAPL source located below the water table, and consequently assess the indoor air exposure risk under multiple hydrologic uncertainties. For this purpose, a multi-phase multi-component numerical model, CompFlow Bio is used to simulate the evolution of a TCE source zone and dissolved plume in a variably saturated heterogeneous aquifer, along with the transport of dissolved TCE upwards through the capillary fringe with subsequent migration of TCE vapors in the vadose zone subject to barometric pressure fluctuations. The TCE vapors then enter the basement of the residential dwelling through a crack in the foundation slab, driven by a slight vacuum within the basement relative to the ambient atmosphere as well as the barometric pressure fluctuations. Hydrologic uncertainties affecting the indoor air concentration of TCE include the vacuum in the basement, the aperture of the crack in the foundation slab, the heterogeneous permeability field, the thickness of the capillary fringe, barometric fluctuations, recharge rates and the location of the TCE source zone. CompFlow Bio is then used to determine the future concentration of TCE into the basement as a consequence of imperfect knowledge in the various hydrologic parameters, and to evaluate the effectiveness of alternative remedial and foundation design options to minimize the exposure risk to the indoor air conditional upon the available data collected at the site. The outcome of this approach is two-fold. First, the owner of the site can reasonably evaluate the future indoor air exposure risk following the redevelopment of a formerly contaminated site following remediation

  10. Comparison of observed and predicted Kr-85 air concentrations

    SciTech Connect

    Yildiran, M.; Miller, C.W.

    1984-04-25

    A computer code, ANEMOS has been written to estimate concentrations in air and ground deposition rates for Atmospheric Nuclides Emitted from Multiple Operation Sources. This code uses a modified Gaussian plum equation. Output from ANEMOS includes annual-average air concentrations and ground deposition rates of dispersed radionuclides and daughters. To use the environmental transport model properly, some estimate of the models predictive accuracy must be obtained. To validate the ANEMOS model, one year of weekly average Kr-85 concentrations observed at 13 stations located 28 to 144 km distant from continuous point source at the Savannah River Plant (SRP), Aiken, South Carolina, have been used. There was a general tendency for the model to underpredict the observed air concentrations slightly. Pearsons's correlation between pairs of logarithms of observed and predicted annual-average values was r = 0.84. The monthly results tend to show more scatter than do either the seasonal or the annual comparisons. 18 references, 3 figures, 3 tables.

  11. AIR EMISSIONS FROM THE TREATMENT OF SOILS CONTAMINATED WITH PETROLEUM FUELS AND OTHER SUBSTANCES

    EPA Science Inventory

    The report updates a 1992 report that summarizes available information on air emissions from the treatment of soils contaminated with fuels. Soils contaminated by leaks or spills of fuel products, such as gasoline or jet fuel, are a nationwide concern. Air emissions during remedi...

  12. Bacteriological evaluation of a new air turbine handpiece for preventing cross-contamination in dental procedures.

    PubMed

    Masuda, K; Ohta, M; Ohsuka, S; Matsuyama, M; Ashoori, M; Usami, T; Ito, M; Ueda, M; Kaneda, T

    1994-03-01

    An autoclavable air turbine handpiece, Air Flushing Clean System (AFCS) (Osada Electric Co., Ltd., Tokyo, Japan) was developed for use in dentistry with the objective of reducing cross-contamination. Its potential for bacterial contamination was investigated in vitro using two bacterial strains (Streptococcus mutants ATCC 25175 and Staphylococcus aureus FDA 209 P). In theory, this device should prevent cross-contamination of the internal water and air lines of the handpiece, by maintaining an internal positive pressure even after the turbine is stopped. In the present study, this AFCS device was found to reduce the bacterial contamination within the air turbine handpiece more effectively than the conventional handpiece used according to accepted protocol. The reduction of such contamination by the AFCS is in keeping with the recent objective of the American Dental Association to reduce cross-contamination during dental procedures.

  13. (Environmental investigation of ground water contamination at Wright-Patterson Air Force Base, Ohio)

    SciTech Connect

    Not Available

    1992-03-01

    The Phase I, Task 5, Focused Feasibility Study (FFS) has been prepared as part of the Environmental Investigation of Ground Water Contamination Project being conducted by Wright-Patterson Air Force Base (WPAFB). The primary objective of this FFS was to select a cost-effective method of preventing migration of contaminated ground water across the southwestern boundary of Area C of the Base. The FFS presented in this document is a portion of a much larger effort being conducted at WPAFB. The detailed analysis of alternatives for the extraction, treatment, and discharge of contaminated ground water migrating across the southwest boundary of Area C at WPAFB led to the selection of a preferred removal action alternative. Specifically, this alternative is that ground water be extracted utilizing a three well array pumping at a total of 400 to 800 gpm, removed water be treated via air stripping to achieve appropriate effluent concentrations, and treated water be discharged to the Mad River in accordance with a National Pollution Discharge Elimination System (NPDES) permit and other relevant permits.

  14. Methods for Environments and Contaminants: Criteria Air Pollutants

    EPA Pesticide Factsheets

    EPA’s Office of Air Quality Planning and Standards (OAQPS) has set primary (health-based) National Ambient Air Quality Standards (NAAQS) for six common air pollutants, often referred to as criteria air pollutants (or simply criteria pollutants).

  15. Histopathology and contaminant concentrations in fish from Kuwait's marine environment.

    PubMed

    Al-Zaidan, A S; Al-Sarawi, H A; Massoud, M S; Al-Enezi, M; Smith, A J; Bignell, J P; Green, M J; Askem, C; Bolam, T P C; Barber, J L; Bersuder, P; Lyons, B P

    2015-11-30

    Kuwait has witnessed major socioeconomic and industrial development in recent decades. Consequently, a variety of contaminants related to these activities have been discharged directly into the marine environment. This paper describes the application of a histopathology baseline survey in two potential sentinel species, the Giant sea catfish (Arius thalassinus) and the Fourlined terapon (Pelates quadrilineatus) to assess the health of biota inhabiting Kuwait's marine environment. Histological analysis revealed several lesion types in both species, although the prevalence was generally considered low with no discernible differences between sampling locations. The analysis of contaminant burdens (metals, PCBs, PBDEs, HBCDD) in A. thalassinus, along with the analysis of bile for PAH metabolites in both species, indicated that levels of contaminant exposure was low. Overall the data show that both species appear to be susceptible to pathologies associated with environmental contaminants and therefore suitable for further investigation as sentinel organisms for biological effects monitoring.

  16. Seasonal variations of air pollutant concentrations within Krasnoyarsk City.

    PubMed

    Mikhailuta, Sergey V; Taseiko, Olga V; Pitt, Anne; Lezhenin, Anatoly A; Zakharov, Yuri V

    2009-02-01

    This paper examines the significant differences in seasonal variations of criteria pollutant concentrations in various parts of a large urban area. These differences are caused by the microclimatic heterogeneity of the city and show the influence of breeze and orographic-type circulations on urban air pollution. The temperature heterogeneity of Krasnoyarsk territory during the winter leads to an increase of 150% in CO air pollution levels in the central part of city. During the summer the orographical heterogeneity of Krasnoyarsk City leads to increases of up to 400% in air pollution for different areas.

  17. Ozone concentrations in air flowing into New York State

    NASA Astrophysics Data System (ADS)

    Aleksic, Nenad; Kent, John; Walcek, Chris

    2016-09-01

    Ozone (O3) concentrations measured at Pinnacle State Park (PSPNY), very close to the southern border of New York State, are used to estimate concentrations in air flowing into New York. On 20% of the ozone season (April-September) afternoons from 2004 to 2015, mid-afternoon 500-m back trajectories calculated from PSPNY cross New York border from the south and spend less than three hours in New York State, in this area of negligible local pollution emissions. One-hour (2p.m.-3p.m.) O3 concentrations during these inflowing conditions were 46 ± 13 ppb, and ranged from a minimum of 15 ppb to a maximum of 84 ppb. On average during 2004-2015, each year experienced 11.8 days with inflowing 1-hr O3 concentrations exceeding 50 ppb, 4.3 days with O3 > 60 ppb, and 1.5 days had O3 > 70 ppb. During the same period, 8-hr average concentrations (10a.m. to 6p.m.) exceeded 50 ppb on 10.0 days per season, while 3.9 days exceeded 60 ppb, and 70 ppb was exceeded 1.2 days per season. Two afternoons of minimal in-state emission influences with high ozone concentrations were analyzed in more detail. Synoptic and back trajectory analysis, including comparison with upwind ozone concentrations, indicated that the two periods were characterized as photo-chemically aged air containing high inflowing O3 concentrations most likely heavily influenced by pollution emissions from states upwind of New York including Pennsylvania, Tennessee, West Virginia, and Ohio. These results suggest that New York state-level attempts to comply with National Ambient Air Quality Standards by regulating in-state O3 precursor NOx and organic emissions would be very difficult, since air frequently enters New York State very close to or in excess of Federal Air Quality Standards.

  18. Plasticizers, antioxidants, and other contaminants found in air delivered by PVC tubing used in respiratory therapy.

    PubMed

    Hill, Sandra S; Shaw, Brenda R; Wu, Alan H B

    2003-06-01

    Of the many compounds that leach from respiratory therapy tubing into air passing through it, we selected five compounds to analyze. The five compounds are known to be potentially carcinogenic, toxic or known to induce estrogenic activity. Parts-per-million and parts-per-billion concentrations of these species were found in the air passing through the tubing: the plasticizers di-(2-ethylhexyl) phthalate (DEHP) and di-ethyl phthalate (DEP), the antioxidants butylated hydroxy toluene (BHT) and p-nonylphenol (p-NP), and the contaminant (from commercial preparation of DEHP) 2-ethylhexanol (2-EH). These levels are high enough to cause some concern about exposure for patients who use oxygen on a long-term basis, those sensitive or allergic to these species, or those with asthma. A method was developed for analysis of solid tubing samples, showing great variability in concentrations of small, volatile molecules from sample to sample. A method was also developed for pre-concentration of small molecules onto Tenax adsorbants from air passing through the tubing. Both solid samples and adsorbant loaded with analyte were analyzed by direct dynamic thermal desorption gas chromatography mass spectrometry (GCMS). This study does not imply that adverse reactions by patients to chemical compounds leaching from respiratory medical tubing will occur but that further investigation is warranted.

  19. Hazard Assessment of Chemical Air Contaminants Measured in Residences

    SciTech Connect

    Logue, J.M.; McKone, T.E.; Sherman, M. H.; Singer, B.C.

    2010-05-10

    Identifying air pollutants that pose a potential hazard indoors can facilitate exposure mitigation. In this study, we compiled summary results from 77 published studies reporting measurements of chemical pollutants in residences in the United States and in countries with similar lifestyles. These data were used to calculate representative mid-range and upper bound concentrations relevant to chronic exposures for 267 pollutants and representative peak concentrations relevant to acute exposures for 5 activity-associated pollutants. Representative concentrations are compared to available chronic and acute health standards for 97 pollutants. Fifteen pollutants appear to exceed chronic health standards in a large fraction of homes. Nine other pollutants are identified as potential chronic health hazards in a substantial minority of homes and an additional nine are identified as potential hazards in a very small percentage of homes. Nine pollutants are identified as priority hazards based on the robustness of measured concentration data and the fraction of residences that appear to be impacted: acetaldehyde; acrolein; benzene; 1,3-butadiene; 1,4-dichlorobenzene; formaldehyde; naphthalene; nitrogen dioxide; and PM{sub 2.5}. Activity-based emissions are shown to pose potential acute health hazards for PM{sub 2.5}, formaldehyde, CO, chloroform, and NO{sub 2}.

  20. Spectra of concentration of air pollution for turbulent convection

    SciTech Connect

    Patel, S.R.

    1996-12-31

    Very recently the study of formation and destruction of photochemical smog is increasing at both small and large scale. Also the transport of chemical species through the Planetary Boundary Layer (PBL) of the atmosphere is a key of the global change problem and will have to be parameterized more reliably than in the past. Further, in the air pollution modeling, the usual practice of neglecting the concentration correlation in the atmospheric photochemical reaction has recently been recognized as a source of serious error. So, it is important to study the various aspects of the concentration fluctuations (of air pollution) with chemical reaction. A model of the spectrum of concentration of air pollution with chemical reaction has been developed using the models of Hill and Hill and Clifford. The results obtained are applicable for arbitrary Schmidt number. Further, for the case of pure mixing (without chemical reaction) and the concentration replaced by temperature, the form of the spectra obtained here reduces to the form obtained by Hill and Clifford. This study also shows that, in the case of pure mixing, the concentration decays in a natural manner, but if the concentration selected is that of the chemical reactant, then the effect is that the dispersion of the concentration is much more rapid.

  1. Development of a model for radon concentration in indoor air.

    PubMed

    Jelle, Bjørn Petter

    2012-02-01

    A model is developed for calculation of the radon concentration in indoor air. The model takes into account various important parameters, e.g. radon concentration in ground, radon diffusion resistance of radon barrier, air permeance of ground, air pressure difference between outdoor ground and indoor at ground level, ventilation of the building ground and number of air changes per hour due to ventilation. Characteristic case studies are depicted in selected 2D and 3D graphical plots for easy visualization and interpretation. The radon transport into buildings might be dominated by diffusion, pressure driven flow or a mixture of both depending on the actual values of the various parameters. The results of our work indicate that with realistic or typical values of the parameters, most of the transport of radon from the building ground to the indoor air is due to air leakage driven by pressure differences through the construction. By incorporation of various and realistic values in the radon model, valuable information about the miscellaneous parameters influencing the indoor radon level is gained. Hence, the presented radon model may be utilized as a simple yet versatile and powerful tool for examining which preventive or remedial measures should be carried out to achieve an indoor radon level below the reference level as set by the authorities.

  2. Characterization of air contaminants formed by the interaction of lava and sea water.

    PubMed

    Kullman, G J; Jones, W G; Cornwell, R J; Parker, J E

    1994-05-01

    We made environmental measurements to characterize contaminants generated when basaltic lava from Hawaii's Kilauea volcano enters sea water. This interaction of lava with sea water produces large clouds of mist (LAZE). Island winds occasionally directed the LAZE toward the adjacent village of Kalapana and the Hawaii Volcanos National Park, creating health concerns. Environmental samples were taken to measure airborne concentrations of respirable dust, crystalline silica and other mineral compounds, fibers, trace metals, inorganic acids, and organic and inorganic gases. The LAZE contained quantifiable concentrations of hydrochloric acid (HCl) and hydrofluoric acid (HF); HCl was predominant. HCl and HF concentrations were highest in dense plumes of LAZE near the sea. The HCl concentration at this sampling location averaged 7.1 ppm; this exceeds the current occupational exposure ceiling of 5 ppm. HF was detected in nearly half the samples, but all concentrations were <1 ppm Sulfur dioxide was detected in one of four short-term indicator tube samples at approximately 1.5 ppm. Airborne particulates were composed largely of chloride salts (predominantly sodium chloride). Crystalline silica concentrations were below detectable limits, less than approximately 0.03 mg/m3 of air. Settled dust samples showed a predominance of glass flakes and glass fibers. Airborne fibers were detected at quantifiable levels in 1 of 11 samples. These fibers were composed largely of hydrated calcium sulfate. These findings suggest that individuals should avoid concentrated plumes of LAZE near its origin to prevent over exposure to inorganic acids, specifically HCl.

  3. Auditing and assessing air quality in concentrated feeding operations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The potential adverse effects of concentrated animal feeding operations (CAFO) on the environment are a growing concern. The air quality issues of most concerns to CAFO vary, but generally include ammonia, hydrogen sulfide, particulate matter (PM), volatile organic compounds (VOC), green house gase...

  4. Use of Source Term and Air Dispersion Modeling in Planning Demolition of Highly Alpha-Contaminated Buildings

    SciTech Connect

    Droppo, James G.; Napier, Bruce A.; Rishel, Jeremy P.; Bloom, Richard W.

    2011-06-22

    The current cleanup of structures related to cold-war production of nuclear materials includes the need to demolish a number of highly alpha-contaminated structures. The process of planning for the demolition of such structures includes unique challenges related to ensuring the protection of both workers and the public. Pre-demolition modeling analyses were conducted to evaluate potential exposures resulting from the proposed demolition of a number of these structures. Estimated emission rates of transuranic materials during demolition are used as input to an air-dispersion model. The climatological frequencies of occurrence of peak air and surface exposures at locations of interest are estimated based on years of hourly meteorological records. The modeling results indicate that downwind deposition is the main operational limitation for demolition of a highly alpha-contaminated building. The pre-demolition modeling directed the need for better contamination characterization and/or different demolition methods—and in the end, provided a basis for proceeding with the planned demolition activities. Post-demolition modeling was also conducted for several contaminated structures, based on the actual demolition schedule and conditions. Comparisons of modeled and monitoring results are shown. Recent monitoring data from the demolition of a UO3 plant shows increments in concentrations that were previously identified in the pre-demolition modeling predictions; these comparisons confirm the validity and value of the pre-demolition source-term and air dispersion computations for planning demolition activities for other buildings with high levels of radioactive contamination.

  5. Determination of beryllium concentrations in UK ambient air

    NASA Astrophysics Data System (ADS)

    Goddard, Sharon L.; Brown, Richard J. C.; Ghatora, Baljit K.

    2016-12-01

    Air quality monitoring of ambient air is essential to minimise the exposure of the general population to toxic substances such as heavy metals, and thus the health risks associated with them. In the UK, ambient air is already monitored under the UK Heavy Metals Monitoring Network for a number of heavy metals, including nickel (Ni), arsenic (As), cadmium (Cd) and lead (Pb) to ensure compliance with legislative limits. However, the UK Expert Panel on Air Quality Standards (EPAQS) has highlighted a need to limit concentrations of beryllium (Be) in air, which is not currently monitored, because of its toxicity. The aim of this work was to analyse airborne particulate matter (PM) sampled onto filter papers from the UK Heavy Metals Monitoring Network for quantitative, trace level beryllium determination and compare the results to the guideline concentration specified by EPAQS. Samples were prepared by microwave acid digestion in a matrix of 2% sulphuric acid and 14% nitric acid, verified by the use of Certified Reference Materials (CRMs). The digested samples were then analysed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The filters from the UK Heavy Metals Monitoring Network were tested using this procedure and the average beryllium concentration across the network for the duration of the study period was 7.87 pg m-3. The highest site average concentration was 32.0 pg m-3 at Scunthorpe Low Santon, which is significantly lower than levels that are thought to cause harm. However the highest levels were observed at sites monitoring industrial point sources, indicating that beryllium is being used and emitted, albeit at very low levels, from these point sources. Comparison with other metals concentrations and data from the UK National Atmospheric Emissions Inventory suggests that current emissions of beryllium may be significantly overestimated.

  6. Forecasting contaminant concentrations: Spills in the White Oak Creek Basin

    SciTech Connect

    Borders, D.M.; Hyndman, D.W.; Huff, D.D.

    1987-01-01

    The Streamflow Synthesis and Reservoir Regulation (SSARR) model has been installed and sufficiently calibrated for use in managing accidental release of contaminants in surface waters of the White Oak Creek (WOC) watershed at ORNL. The model employs existing watershed conditions, hydrologic parameters representing basin response to precipitation, and a Quantitative Precipitation Forecast (QPF) to predict variable flow conditions throughout the basin. Natural runoff from each of the hydrologically distinct subbasins is simulated and added to specified plant and process water discharges. The resulting flows are then routed through stream reaches and eventually to White Oak Lake (WOL), which is the outlet from the WOC drainage basin. In addition, the SSARR model is being used to simulate change in storage volumes and pool levels in WOL, and most recently, routing characteristics of contaminant spills through WOC and WOL. 10 figs.

  7. Methodology for the determination of normal background concentrations of contaminants in English soil.

    PubMed

    Ander, E Louise; Johnson, Christopher C; Cave, Mark R; Palumbo-Roe, Barbara; Nathanail, C Paul; Lark, R Murray

    2013-06-01

    The revised Environmental Protection Act Part 2A contaminated land Statutory Guidance (England and Wales) makes reference to 'normal' levels of contaminants in soil. The British Geological Survey has been commissioned by the United Kingdom Department for Environment, Food and Rural Affairs (Defra) to estimate contaminant levels in soil and to define what is meant by 'normal' for English soil. The Guidance states that 'normal' levels of contaminants are typical and widespread and arise from a combination of both natural and diffuse pollution contributions. Available systematically collected soil data sets for England are explored for inorganic contaminants (As, Cd, Cu, Hg, Ni and Pb) and benzo[a]pyrene (BaP). Spatial variability of contaminants is studied in the context of the underlying parent material, metalliferous mineralisation and associated mining activities, and the built (urban) environment, the latter being indicative of human activities such as industry and transportation. The most significant areas of elevated contaminant concentrations are identified as contaminant domains. Therefore, rather than estimating a single national contaminant range of concentrations, we assign an upper threshold value to contaminant domains. Our representation of this threshold is a Normal Background Concentration (NBC) defined as the upper 95% confidence limit of the 95th percentile for the soil results associated with a particular domain. Concentrations of a contaminant are considered to be typical and widespread for the identified contaminant domain up to (and including) the calculated NBC. A robust statistical methodology for determining NBCs is presented using inspection of data distribution plots and skewness testing, followed by an appropriate data transformation in order to reduce the effects of point source contamination.

  8. Influence of eutrophication on air-water exchange, vertical fluxes, and phytoplankton concentrations of persistent organic pollutants

    SciTech Connect

    Dachs, J.; Eisenreich, S.J.; Hoff, R.M.

    2000-03-15

    The influence of eutrophication on the biogeochemical cycles of persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs) is largely unknown. In this paper, the application of a dynamic air-water-phytoplankton exchange model to Lake Ontario is used as a framework to study the influence of eutrophication on air-water exchange, vertical fluxes, and phytoplankton concentrations of POPs. The results of these simulations demonstrate that air-water exchange controls phytoplankton concentrations in remote aquatic environments with little influence from land-based sources of pollutants and supports levels in even historically contaminated systems. Furthermore, eutrophication or high biomass leads to a disequilibrium between the gas and dissolved phase, enhanced air-water exchange, and vertical sinking fluxes of PCBs. Increasing biomass also depletes the water concentrations leading to lower than equilibrium PCB concentrations in phytoplankton. Implications to future trends in PCB pollution in Lake Ontario are also discussed.

  9. Application of passive sampling for measuring dissolved concentrations of organic contaminants in the water column at three marine superfund sites

    EPA Science Inventory

    At contaminated sediment sites, including U.S. EPA Superfund sites, it is critical to measure water column concentrations of freely dissolved contaminants to understand the complete exposure of aquatic organisms to hydrophobic organic contaminants (HOCs). However, historically a...

  10. Analysis of industrial contaminants in indoor air: part 1. Volatile organic compounds, carbonyl compounds, polycyclic aromatic hydrocarbons and polychlorinated biphenyls.

    PubMed

    Barro, Ruth; Regueiro, Jorge; Llompart, María; Garcia-Jares, Carmen

    2009-01-16

    This article reviews recent literature on the analysis of industrial contaminants in indoor air in the framework of the REACH project, which is mainly intended to improve protection of human health and the environment from the risks of more than 34 millions of chemical substances. Industrial pollutants that can be found in indoor air may be of very different types and origin, belonging to the volatile organic compounds (VOCs) and semivolatile organic compounds (SVOCs) categories. Several compounds have been classified into the priority organic pollutants (POPs) class such as polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and furans (PCDD/PCDFs) and related polychlorinated compounds, and polycyclic aromatic hydrocarbons (PAHs). Many of these compounds are partially associated to the air gas phase, but also to the suspended particulate matter. Furthermore, settled dust can act as a concentrator for the less volatile pollutants and has become a matrix of great concern for indoors contamination. Main literature considered in this review are papers from the last 10 years reporting analytical developments and applications regarding VOCs, aldehydes and other carbonyls, PCBs, PCDDs, PCDFs, and PAHs in the indoor environment. Sample collection and pretreatment, analyte extraction, clean-up procedures, determination techniques, performance results, as well as compound concentrations in indoor samples, are summarized and discussed. Emergent contaminants and pesticides related to the industrial development that can be found in indoor air are reviewed in a second part in this volume.

  11. (Environmental investigation of ground water contamination at Wright-Patterson Air Force Base, Ohio)

    SciTech Connect

    Not Available

    1991-10-01

    This report presents information concerning field procedures employed during the monitoring, well construction, well purging, sampling, and well logging at the Wright-Patterson Air Force Base. Activities were conducted in an effort to evaluate ground water contamination.

  12. Microbial contamination of ambient air by ultrasonic humidifier and preventive measures.

    PubMed

    Oie, S; Masumoto, N; Hironaga, K; Koshiro, A; Kamiya, A

    1992-01-01

    The microbially contaminated ultrasonic humidifier (UH) causes humidifier fever. The number of airborne viable bacteria was determined when the UH was operating, and other methods to humidify the air of hospital wards were also examined. A UH contaminated with 10(5) bacteria ml(-1), a level common in hospitals, increased the bacterial count in the air from 860 m(-3) to 88,000 m(-3) at a distance of 3 m from the humidifier. Thus UH in hospitals may contaminate the air and be a potential hazard to patients. Contamination was slight when a washable and disinfectable ultrasonic nebulizer was used with disinfection at 24 h intervals. In tracheostomy patients requiring a high degree of air humidification, ultrasonic nebulizers which are readily washed and disinfected are recommended.

  13. Increased concentrations of potassium in heartwood of trees in response to groundwater contamination

    USGS Publications Warehouse

    Vroblesky, D.A.; Yanosky, T.M.; Siegel, F.R.

    1992-01-01

    The wood of tuliptrees (Liriodendron tulipifera L.) growing above groundwater contamination from a hazardous-waste landfill in Maryland contained elevated concentrations of potassium (K). The groundwater contamination also contained elevated concentrations of dissolved K, as well as arsenic (As), cadmium (Cd), chloride (Cl), iron (Fe), manganese (Mn), zinc (Zn), and organic solvents. The dissolved K is derived from disposed smoke munitions. The excess K in the tuliptrees is concentrated in the heartwood, the part of the xylem most depleted in K in trees growing outside of the contamination. These data show that the uptake and translocation of K by tuliptrees can be strongly influenced by the availability of K in groundwater contamination and suggest the utility of this species as an areal indicator of groundwater contamination. ?? 1992 Springer-Verlag New York Inc.

  14. Air Sampling Instruments for Evaluation of Atmospheric Contaminants. Fourth Edition.

    ERIC Educational Resources Information Center

    American Conference of Governmental Industrial Hygienists, Cincinnati, OH.

    This text, a revision and extension of the first three editions, consists of papers discussing the basic considerations in sampling air for specific purposes, sampler calibration, systems components, sample collectors, and descriptions of air-sampling instruments. (BT)

  15. Predicting indoor pollutant concentrations, and applications to air quality management

    SciTech Connect

    Lorenzetti, David M.

    2002-10-01

    Because most people spend more than 90% of their time indoors, predicting exposure to airborne pollutants requires models that incorporate the effect of buildings. Buildings affect the exposure of their occupants in a number of ways, both by design (for example, filters in ventilation systems remove particles) and incidentally (for example, sorption on walls can reduce peak concentrations, but prolong exposure to semivolatile organic compounds). Furthermore, building materials and occupant activities can generate pollutants. Indoor air quality depends not only on outdoor air quality, but also on the design, maintenance, and use of the building. For example, ''sick building'' symptoms such as respiratory problems and headaches have been related to the presence of air-conditioning systems, to carpeting, to low ventilation rates, and to high occupant density (1). The physical processes of interest apply even in simple structures such as homes. Indoor air quality models simulate the processes, such as ventilation and filtration, that control pollutant concentrations in a building. Section 2 describes the modeling approach, and the important transport processes in buildings. Because advection usually dominates among the transport processes, Sections 3 and 4 describe methods for predicting airflows. The concluding section summarizes the application of these models.

  16. Estimating the radon concentration in water and indoor air.

    PubMed

    Maged, A F

    2009-05-01

    The paper presents the results of radon concentration measurements in the vicinity of water, indoor air and in contact to building walls. The investigations were carried out using CR-39 track detectors. Samples of ground water flowing out of many springs mostly in Arabian Gulf area except one from Germany have been studied. The results are compared with international recommendations and the values are found to be lower than the recommended value. Measuring the mean indoor radon concentrations in air and in contact to building walls in the dwellings of Kuwait University Campus were found 24.2 +/- 7.7, and 462 +/- 422 Bq m(-3) respectively. These values lead to average effective dose equivalent rates of 1.3 +/- 0.4 and 23 +/- 21 mSv year(-1), respectively.

  17. Performance of passive samplers for monitoring estuarine water column concentrations: 2. Emerging contaminants.

    PubMed

    Perron, Monique M; Burgess, Robert M; Suuberg, Eric M; Cantwell, Mark G; Pennell, Kelly G

    2013-10-01

    Measuring dissolved concentrations of emerging contaminants, such as polybrominated diphenyl ethers (PBDEs) and triclosan, can be challenging due to their physicochemical properties resulting in low aqueous solubilities and association with particles. Passive sampling methods have been applied to assess dissolved concentrations in water and sediments primarily for legacy contaminants. Although the technology is applicable to some emerging contaminants, the use of passive samplers with emerging contaminants is limited. In the present study, the performance of 3 common passive samplers was evaluated for sampling PBDEs and triclosan. Passive sampling polymers included low-density polyethylene (PE) and polyoxymethylene (POM) sheets, and polydimethylsiloxane (PDMS)-coated solid-phase microextraction (SPME) fibers. Dissolved concentrations were calculated using measured sampler concentrations and laboratory-derived partition coefficients. Dissolved tri-, tetra-, and pentabrominated PBDE congeners were detected at several of the study sites at very low pg/L concentrations using PE and POM. Calculated dissolved water concentrations of triclosan ranged from 1.7 ng/L to 18 ng/L for POM and 8.8 ng/L to 13 ng/L for PE using performance reference compound equilibrium adjustments. Concentrations in SPME were not reported due to lack of detectable chemical in the PDMS polymer deployed. Although both PE and POM were found to effectively accumulate emerging contaminants from the water column, further research is needed to determine their utility as passive sampling devices for emerging contaminants.

  18. Performance of Passive Samplers for Monitoring Estuarine Water Column Concentrations: 2. Emerging Contaminants

    PubMed Central

    Perron, Monique M.; Burgess, Robert M.; Suuberg, Eric M.; Cantwell, Mark G.; Pennell, Kelly G.

    2014-01-01

    Measuring dissolved concentrations of emerging contaminants, such as polybrominated diphenyl ethers (PBDEs) and triclosan, can be challenging due to their physicochemical properties resulting in low aqueous solubilities and association with particles. Passive sampling methods have been applied to assess dissolved concentrations in water and sediments primarily for legacy contaminants. Although the technology is applicable to some emerging contaminants, the use of passive samplers with emerging contaminants is limited. In the present study, the performance of three common passive samplers was evaluated for sampling PBDEs and triclosan. Passive sampling polymers included low density polyethylene (PE) and polyoxymethylene (POM) sheets, and polydimethylsiloxane (PDMS) coated solid phase microextraction (SPME) fibers. Dissolved concentrations were calculated using measured sampler concentrations and laboratory derived partition coefficients. Dissolved tri-, tetra-, and pentabrominated PBDE congeners were detected at several of the study sites at very low pg/L concentrations using PE and POM. Calculated dissolved water concentrations of triclosan ranged from 1.7 to 18 ng/L for POM and 8.8 to 13 ng/L for PE using performance reference compound (PRC) equilibrium adjustments. Concentrations in SPME were not reported due to lack of detectable chemical in the PDMS polymer deployed. Although both PE and POM were found to effectively accumulate emerging contaminants from the water column, further research is needed to determine their utility as passive sampling devices for emerging contaminants. PMID:23595851

  19. Variability of air ion concentrations in urban Paris

    NASA Astrophysics Data System (ADS)

    Dos Santos, V. N.; Herrmann, E.; Manninen, H. E.; Hussein, T.; Hakala, J.; Nieminen, T.; Aalto, P. P.; Merkel, M.; Wiedensohler, A.; Kulmala, M.; Petäjä, T.; Hämeri, K.

    2015-12-01

    Air ion concentrations influence new particle formation and consequently the global aerosol as potential cloud condensation nuclei. We aimed to evaluate air ion concentrations and characteristics of new particle formation events (NPF) in the megacity of Paris, France, within the MEGAPOLI (Megacities: Emissions, urban, regional and Global Atmospheric Pollution and climate effects, and Integrated tools for assessment and mitigation) project. We measured air ion number size distributions (0.8-42 nm) with an air ion spectrometer and fine particle number concentrations (> 6 nm) with a twin differential mobility particle sizer in an urban site of Paris between 26 June 2009 and 4 October 2010. Air ions were size classified as small (0.8-2 nm), intermediate (2-7 nm), and large (7-20 nm). The median concentrations of small and large ions were 670 and 680 cm-3, respectively, (sum of positive and negative polarities), whereas the median concentration of intermediate ions was only 20 cm-3, as these ions were mostly present during new particle formation bursts, i.e. when gas-to-particle conversion produced fresh aerosol particles from gas phase precursors. During peaks in traffic-related particle number, the concentrations of small and intermediate ions decreased, whereas the concentrations of large ions increased. Seasonal variations affected the ion population differently, with respect to their size and polarity. NPF was observed in 13 % of the days, being most frequent in spring and late summer (April, May, July, and August). The results also suggest that NPF was favoured on the weekends in comparison to workdays, likely due to the lower levels of condensation sinks in the mornings of weekends (CS weekdays 09:00: 18 × 10-3 s-1; CS weekend 09:00: 8 × 10-3 s-1). The median growth rates (GR) of ions during the NPF events varied between 3 and 7 nm h-1, increasing with the ion size and being higher on workdays than on weekends for intermediate and large ions. The median GR of

  20. Air radon concentration decrease in a waste water treatment plant.

    PubMed

    Juste, B; Ortiz, J; Verdú, G; Martorell, S

    2015-06-01

    (222)Rn is a naturally occurring gas created from the decay of (226)Ra. The long-term health risk of breathing radon is lung cancer. One particular place where indoor radon concentrations can exceed national guidelines is in wastewater treatment plants (WWTPs) where treatment processes may contribute to ambient airborne concentrations. The aim of this paper was to study the radon concentration decrease after the application of corrective measures in a Spanish WWTP. According to first measures, air radon concentration exceeded International Commission Radiologica1 Protection (ICRP) normative (recommends intervention between 400 and 1000 Bq m(-3)). Therefore, the WWTP improved mechanical forced ventilation to lower occupational exposure. This measure allowed to increase the administrative controls, since the limitation of workers access to the plant changed from 2 h d(-1) (considering a maximum permissible dose of 20 mSv y(-1) averaged over 5 y) to 7 h d(-1).

  1. Spatiotemporal characteristics of organic contaminant concentrations and ecological risk assessment in the Songhua River, China

    EPA Science Inventory

    To control source pollution and improve water quality, an understanding of the spatiotemporal characteristics of organic contaminant concentrations in affected receiving waters is necessary. The Songhua River in northeast China is the country's third-largest domestic river and lo...

  2. Performance of Passive Samplers for Monitoring Estuarine Water Column Concentrations: 2. Emerging Contaminants

    EPA Science Inventory

    Measuring dissolved concentrations of emerging contaminants, such as polybrominated diphenyl ethers (PBDEs) and triclosan (TCS), can be challenging due to their physicochemical properties resulting in low aqueous solubilities and association with particles. Passive sampling meth...

  3. A SURVEY OF INDOOR AIR CONTAMINATES USING SEMIPERMEABLE MEMBRANE DEVICES

    EPA Science Inventory

    Semipermeable membrane devices (SPMDs) were deployed in indoor areas in approximately 50 residences along the border between Arizona and Mexico to measure airborne contaminants. The results of the primary analyses and gas chromatographic/mass spectrometric confirmation for org...

  4. Effect of laminar air flow and clean-room dress on contamination rates of intravenous admixtures.

    PubMed

    Brier, K L; Latiolais, C J; Schneider, P J; Moore, T D; Buesching, W J; Wentworth, B C

    1981-08-01

    The effect of laminar air flow conditions and clean-room dress on the microbial contamination rates of intravenous admixtures was investigated. Intravenous admixtures were prepared by one investigator using aseptic technique under four environmental conditions: laminar air flow conditions with clean-room dress; laminar air flow without clean-room dress; clean table top with clean-room dress; and clean table top without clean-room dress. In each environmental condition, 350 admixtures were compounded. Negative-control samples (n = 150) were also tested, as were 10 positive-control samples. Samples were tested in each of two growth media and incubated at 35 degrees C for 14 days or until growth occurred. The incidence of contamination of admixtures compounded in laminar air flow conditions was significantly less than the contamination of those compounded on a clean table top (p less than 0.05) regardless of the operator's dress. The incidence of contamination of admixtures compounded while wearing clean-room dress was not significantly different from those prepared while not wearing clean-room dress regardless of the environment in which the admixture was prepared. The overall low level of contamination [0.79% (11/1400)] was inconclusive regarding the effect of dress on the incidence of contamination when admixtures were prepared under LAF conditions. It is concluded that, when one adheres to aseptic technique, the environment in which admixtures are compounded is the most important variable affecting the microbial contamination rate.

  5. Effects of H2O, CO2, and N2 Air Contaminants on Critical Airside Strain Rates for Extinction of Hydrogen-Air Counterflow Diffusion Flames

    NASA Technical Reports Server (NTRS)

    Pellett, G. L.; Wilson, L. G.; Northam, G. B.; Guerra, Rosemary

    1989-01-01

    Coaxial tubular opposed jet burners (OJB) were used to form dish shaped counterflow diffusion flames (CFDF), centered by opposing laminar jets of H2, N2 and both clean and contaminated air (O2/N2 mixtures) in an argon bath at 1 atm. Jet velocities for flame extinction and restoration limits are shown versus wide ranges of contaminant and O2 concentrations in the air jet, and also input H2 concentration. Blowoff, a sudden breaking of CFDF to a stable ring shape, occurs in highly stretched stagnation flows and is generally believed to measure kinetically limited flame reactivity. Restore, a sudden restoration of central flame, is a relatively new phenomenon which exhibits a H2 dependent hysteresis from Blowoff. For 25 percent O2 air mixtures, mole for mole replacement of 25 percent N2 contaminant by steam increased U(air) or flame strength at Blowoff by about 5 percent. This result is consistent with laminar burning velocity results from analogous substitution of steam for N2 in a premixed stoichiometric H2-O2-N2 (or steam) flame, shown by Koroll and Mulpuru to promote a 10 percent increase in experimental and calculated laminar burning velocity, due to enhanced third body efficiency of water in: H + O2 + M yields HO2 + M. When the OJB results were compared with Liu and MacFarlane's experimental laminar burning velocity of premixed stoichiometric H2 + air + steam, a crossover occurred, i.e., steam enhanced OJB flame strength at extinction relative to laminar burning velocity.

  6. Heavy metal concentrations in edible barnacles exposed to natural contamination.

    PubMed

    Dionísio, M; Costa, A; Rodrigues, A

    2013-04-01

    The giant barnacle Megabalanus azoricus is a popular seafood in the Azores. It is mainly caught in coastal environments and sold for domestic human consumption. This species is a filter feeder and can be used as a biomonitor of trace metal bioavailabilities. To investigate consumption safety, the concentrations of 10 trace metals - As, Cd, Cr, Cu, Mn, Pb, Rb, Se, Sr and Zn - were evaluated in 3 body tissues of M. azoricus from 3 sites on 2 islands. There were no significant differences between the metal loads of the barnacles from the different sites. However, the concentrations of the total trace metal loads revealed significant differences among the tissues (cirrus, muscles and ovaries). The concentrations of some metals in the body were not within the safety levels for consumers, based on the allowable standard levels for crustaceans issued by the European Union and of legislations in several countries. Alarming levels of As and Cd were found. Considering the absence of heavy industry in the region, a non-anthropogenic volcanic source was assumed to be the reason for the observed metal levels. Barnacles, in particular M. azoricus, seem to be useful as bioindicators in this peculiar environment.

  7. Groundwater level and nitrate concentration trends on Mountain Home Air Force Base, southwestern Idaho

    USGS Publications Warehouse

    Williams, Marshall L.

    2014-01-01

    Mountain Home Air Force Base in southwestern Idaho draws most of its drinking water from the regional aquifer. The base is located within the State of Idaho's Mountain Home Groundwater Management Area and is adjacent to the State's Cinder Cone Butte Critical Groundwater Area. Both areas were established by the Idaho Department of Water Resources in the early 1980s because of declining water levels in the regional aquifer. The base also is listed by the Idaho Department of Environmental Quality as a nitrate priority area. The U.S. Geological Survey, in cooperation with the U.S. Air Force, began monitoring wells on the base in 1985, and currently monitors 25 wells for water levels and 17 wells for water quality, primarily nutrients. This report provides a summary of water-level and nitrate concentration data collected primarily between 2001 and 2013 and examines trends in those data. A Regional Kendall Test was run to combine results from all wells to determine an overall regional trend in water level. Groundwater levels declined at an average rate of about 1.08 feet per year. Nitrate concentration trends show that 3 wells (18 percent) are increasing in nitrate concentration trend, 3 wells (18 percent) show a decreasing nitrate concentration trend, and 11 wells (64 percent) show no nitrate concentration trend. Six wells (35 percent) currently exceed the U.S. Environmental Protection Agency's maximum contaminant limit of 10 milligrams per liter for nitrate (nitrite plus nitrate, measured as nitrogen).

  8. Characterization of air contaminants formed by the interaction of lava and sea water.

    PubMed Central

    Kullman, G J; Jones, W G; Cornwell, R J; Parker, J E

    1994-01-01

    We made environmental measurements to characterize contaminants generated when basaltic lava from Hawaii's Kilauea volcano enters sea water. This interaction of lava with sea water produces large clouds of mist (LAZE). Island winds occasionally directed the LAZE toward the adjacent village of Kalapana and the Hawaii Volcanos National Park, creating health concerns. Environmental samples were taken to measure airborne concentrations of respirable dust, crystalline silica and other mineral compounds, fibers, trace metals, inorganic acids, and organic and inorganic gases. The LAZE contained quantifiable concentrations of hydrochloric acid (HCl) and hydrofluoric acid (HF); HCl was predominant. HCl and HF concentrations were highest in dense plumes of LAZE near the sea. The HCl concentration at this sampling location averaged 7.1 ppm; this exceeds the current occupational exposure ceiling of 5 ppm. HF was detected in nearly half the samples, but all concentrations were <1 ppm Sulfur dioxide was detected in one of four short-term indicator tube samples at approximately 1.5 ppm. Airborne particulates were composed largely of chloride salts (predominantly sodium chloride). Crystalline silica concentrations were below detectable limits, less than approximately 0.03 mg/m3 of air. Settled dust samples showed a predominance of glass flakes and glass fibers. Airborne fibers were detected at quantifiable levels in 1 of 11 samples. These fibers were composed largely of hydrated calcium sulfate. These findings suggest that individuals should avoid concentrated plumes of LAZE near its origin to prevent over exposure to inorganic acids, specifically HCl. Images Figure 1. Figure 2. Figure 3. Figure 4. A Figure 4. B Figure 4. C Figure 4. D PMID:8593853

  9. Evaluating the impact of ambient benzene vapor concentrations on product water from Condensation Water From Air technology.

    PubMed

    Kinder, Katherine M; Gellasch, Christopher A; Dusenbury, James S; Timmes, Thomas C; Hughes, Thomas M

    2017-07-15

    Globally, drinking water resources are diminishing in both quantity and quality. This situation has renewed interest in Condensation Water From Air (CWFA) technology, which utilizes water vapor in the air to produce water for both potable and non-potable purposes. However, there are currently insufficient data available to determine the relationship between air contaminants and the rate at which they are transferred from the air into CWFA untreated product water. This study implemented a novel experimental method utilizing an environmental test chamber to evaluate how air quality and temperature affects CWFA untreated product water quality in order to collect data that will inform the type of water treatment required to protect human health. This study found that temperature and benzene air concentration affected the untreated product water from a CWFA system. Benzene vapor concentrations representing a polluted outdoor environment resulted in benzene product water concentrations between 15% and 23% of the USEPA drinking water limit of 5μg/l. In contrast, product water benzene concentrations representing an indoor industrial environment were between 1.4 and 2.4 times higher than the drinking water limit. Lower condenser coil temperatures were correlated with an increased concentration of benzene in the product water. Environmental health professionals and engineers can integrate the results of this assessment to predict benzene concentrations in the product water and take appropriate health protective measures.

  10. Characterizing contaminant concentrations with depth by using the USGS well profiler in Oklahoma, 2003-9

    USGS Publications Warehouse

    Smith, S. Jerrod; Becker, Carol J.

    2011-01-01

    In 2007, the USGS well profiler was used to investigate saline water intrusion in a deep public-supply well completed in the Ozark (Roubidoux) aquifer. In northeast Oklahoma, where the Ozark aquifer is known to be susceptible to contamination from mining activities, the well profiler also could be used to investigate sources (depths) of metals contamination and to identify routes of entry of metals to production wells.Water suppliers can consider well rehabilitation as a potential remediation strategy because of the ability to identify changes in contaminant concentrations with depth in individual wells with the USGS well profiler. Well rehabilitation methods, which are relatively inexpensive compared to drilling and completing new wells, involve modifying the construction or operation of a well to enhance the production of water from zones with lesser concentrations of a contaminant or to limit the production of water from zones with greater concentrations of a contaminant. One of the most effective well rehabilitation methods is zonal isolation, in which water from contaminated zones is excluded from production through installation of cement plugs or packers. By using relatively simple and inexpensive well rehabilitation methods, water suppliers may be able to decrease exposure of customers to contaminants and avoid costly installation of additional wells, conveyance infrastructure, and treatment technologies.

  11. BOREAS TGB-7 Ambient Air Herbicide and Organochlorine Concentration Data

    NASA Technical Reports Server (NTRS)

    Waite, Don; Hall, Forrest G. (Editor); Conrad, Sara K. (Editor)

    2000-01-01

    The BOReal Ecosystem-Atmosphere Study Trace Gas Biogeochemistry (BOREAS TGB)-7 team measured the concentration and flux of several agricultural pesticides in air, rainwater, and dry deposition samples in order to determine the associated yearly deposition rates. This data set contains information on the ambient air concentration of seven herbicides [2,4- dichlorophenoxyacidic_acid (2,4-D), bromoxynil, dicamb, 2-methyl-4-chlorophenoxyacetic acid (MCPA), triallate, trifluralin, and diclop-methyl] known to appear in the atmosphere of the Canadian prairies. Also, the concentration of three herbicides (atrazine, alachlor, and metolachlor), two groups of insecticides (lindane and breakdown products and dichloro-diphenyl-trichloroethane (DDT) and breakdown products), and several polychlorinated biphenyls commonly used in the central United States was measured. All of these chemicals are reported, in the literature, to be transported in the atmosphere. Many have been reported to occur in boreal and arctic food chains. The sampling was carried out from 16-Jun to 13-Aug-1993 and 04-May to 20-Jul-1994 at the BOREAS site in the Prince Albert National Park (Waskesiu). The data are stored in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884).

  12. A PRINCIPAL COMPONENT ANALYSIS OF THE CLEAN AIR STATUS AND TRENDS NETWORK (CASTNET) AIR CONCENTRATION DATA

    EPA Science Inventory

    The spatial and temporal variability of ambient air concentrations of SO2, SO42-, NO3, HNO3, and NH4+ obtained from EPA's CASTNet was examined using an objective, statistically based technique...

  13. Perfluorinated acids in air, rain, snow, surface runoff, and lakes: relative importance of pathways to contamination of urban lakes.

    PubMed

    Kim, Seung-Kyu; Kannan, Kurunthachalam

    2007-12-15

    Concentrations of perfluorinated acids (PFAs) were measured in various environmental matrices (air, rain, snow, surface runoff water, and lake water) in an urban area, to enable identification of sources and pathways of PFAs to urban water bodies. Total PFA concentrations ranged from 8.28 to 16.0 pg/ m3 (mean 11.3) in bulk air (sum of vapor and particulate phases), 0.91 to 13.2 ng/L (6.19) in rainwater, 0.91 to 23.9 ng/L (7.98) in snow, 1.11-81.8 ng/L (15.1 ng/L) in surface runoff water (SRW), and 9.49 to 35.9 ng/L (21.8) in lake water. Perfluorooctanoic acid (PFOA) was the predominant compound, accounting for > 35% of the total PFA concentrations, in all environmental matrices analyzed. Concentrations and relative compositions of PFAs in SRW were similar to those found for urban lakes. SRW contributes to contamination by PFOA in urban lakes. The measured concentration ratios of FTOH to PFOA in air were 1-2 orders of magnitude lower than the ratios calculated based on an assumption of exclusive atmospheric oxidation of FTOHs. Nevertheless, the mass balance analysis suggested the presence of an unknown input pathway that could contribute to a significant amount of total PFOA loadings to the lake. Flux estimates of PFOA at the air-water interface in the urban lake suggest net volatilization from water.

  14. (Environmental investigation of ground water contamination at Wright-Patterson Air Force Base, Ohio)

    SciTech Connect

    Not Available

    1992-03-01

    An environmental investigation of ground water conditions has been undertaken at Wright-Patterson Air Force Base (WPAFB), Ohio to obtain data to assist in the evaluation of a potential removal action to prevent, to the extent practicable, migration of the contaminated ground water across Base boundaries. Field investigations were limited to the central section of the southwestern boundary of Area C and the Springfield Pike boundary of Area B. Further, the study was limited to a maximum depth of 150 feet below grade. Three primary activities of the field investigation were: (1) installation of 22 monitoring wells, (2) collection and analysis of ground water from 71 locations, (3) measurement of ground water elevations at 69 locations. Volatile organic compounds including trichloroethylene, perchloroethylene, and/or vinyl chloride were detected in concentrations exceeding Maximum Contaminant Levels (MCL) at three locations within the Area C investigation area. Ground water at the Springfield Pike boundary of Area B occurs in two primary units, separated by a thicker-than-expected clay layers. One well within Area B was determined to exceed the MCL for trichloroethylene.

  15. [Ambient and enclosed space air sampling for determination of contaminants].

    PubMed

    Dorogova, V B

    2010-01-01

    The paper touches upon the issues how to correctly and maximally take single and average daily samples of ambient, residential and public building, and enclosed space air for further tests for the content of hazardous substances. The paper is debated.

  16. Micrometeorological Measurement of Fetch- and Atmospheric Stability-Dependent Air- Water Exchange of Legacy Semivolatile Organic Contaminants in Lake Superior

    NASA Astrophysics Data System (ADS)

    Perlinger, J. A.; Tobias, D. E.; Rowe, M. D.

    2008-12-01

    Coastal waters including the Laurentian Great Lakes are particularly susceptible to local, regional, and long- range transport and deposition of semivolatile organic contaminants (SOCs) as gases and/or associated with particles. Recently-marketed SOCs can be expected to undergo net deposition in surface waters, whereas legacy SOCs such as polychlorinated biphenyls (PCBs) are likely to be at equilibrium with respect to air-water exchange, or, if atmospheric concentrations decrease through, e.g., policy implementation, to undergo net gas emission. SOC air-water exchange flux is usually estimated using the two-film model. This model describes molecular diffusion through the air and water films adjacent to the air-water interface. Air-water exchange flux is estimated as the product of SOC fugacity, typically based on on-shore gaseous concentration measurements, and a transfer coefficient, the latter which is estimated from SOC properties and environmental conditions. The transfer coefficient formulation commonly applied neglects resistance to exchange in the internal boundary layer under atmospherically stable conditions, and the use of on-shore gaseous concentration neglects fetch-dependent equilibration, both of which will tend to cause overestimation of flux magnitude. Thus, for legacy chemicals or in any highly contaminated surface water, the rate at which the water is cleansed through gas emission tends to be over-predicted using this approach. Micrometeorological measurement of air-water exchange rates of legacy SOCs was carried out on ships during four transect experiments during off-shore flow in Lake Superior using novel multicapillary collection devices and thermal extraction technology to measure parts-per-quadrillion SOC levels. Employing sensible heat in the modified Bowen ratio, fluxes at three over-water stations along the transects were measured, along with up-wind, onshore gaseous concentration and aqueous concentration. The atmosphere was unstable for

  17. Evaluation of air quality zone classification methods based on ambient air concentration exposure.

    PubMed

    Freeman, Brian; McBean, Ed; Gharabaghi, Bahram; Thé, Jesse

    2017-05-01

    Air quality zones are used by regulatory authorities to implement ambient air standards in order to protect human health. Air quality measurements at discrete air monitoring stations are critical tools to determine whether an air quality zone complies with local air quality standards or is noncompliant. This study presents a novel approach for evaluation of air quality zone classification methods by breaking the concentration distribution of a pollutant measured at an air monitoring station into compliance and exceedance probability density functions (PDFs) and then using Monte Carlo analysis with the Central Limit Theorem to estimate long-term exposure. The purpose of this paper is to compare the risk associated with selecting one ambient air classification approach over another by testing the possible exposure an individual living within a zone may face. The chronic daily intake (CDI) is utilized to compare different pollutant exposures over the classification duration of 3 years between two classification methods. Historical data collected from air monitoring stations in Kuwait are used to build representative models of 1-hr NO2 and 8-hr O3 within a zone that meets the compliance requirements of each method. The first method, the "3 Strike" method, is a conservative approach based on a winner-take-all approach common with most compliance classification methods, while the second, the 99% Rule method, allows for more robust analyses and incorporates long-term trends. A Monte Carlo analysis is used to model the CDI for each pollutant and each method with the zone at a single station and with multiple stations. The model assumes that the zone is already in compliance with air quality standards over the 3 years under the different classification methodologies. The model shows that while the CDI of the two methods differs by 2.7% over the exposure period for the single station case, the large number of samples taken over the duration period impacts the sensitivity of

  18. Concentrations of mobile source air pollutants in urban microenvironments.

    PubMed

    Fujita, Eric M; Campbell, David E; Arnott, W Patrick; Johnson, Ted; Ollison, Will

    2014-07-01

    Human exposures to criteria and hazardous air pollutants (HAPs) in urban areas vary greatly due to temporal-spatial variations in emissions, changing meteorology, varying proximity to sources, as well as due to building, vehicle, and other environmental characteristics that influence the amounts of ambient pollutants that penetrate or infiltrate into these microenvironments. Consequently, the exposure estimates derived from central-site ambient measurements are uncertain and tend to underestimate actual exposures. The Exposure Classification Project (ECP) was conducted to measure pollutant concentrations for common urban microenvironments (MEs) for use in evaluating the results of regulatory human exposure models. Nearly 500 sets of measurements were made in three Los Angeles County communities during fall 2008, winter 2009, and summer 2009. MEs included in-vehicle, near-road, outdoor and indoor locations accessible to the general public. Contemporaneous 1- to 15-min average personal breathing zone concentrations of carbon monoxide (CO), carbon dioxide (CO2), volatile organic compounds (VOCs), nitric oxide (NO), nitrogen oxides (NO(x)), particulate matter (< 2.5 microm diameter; PM2.5) mass, ultrafine particle (UFP; < 100 nm diameter) number black carbon (BC), speciated HAPs (e.g, benzene, toluene, ethylbenzene, xylenes [BTEX], 1,3-butadiene), and ozone (O3) were measured continuously. In-vehicle and inside/outside measurements were made in various passenger vehicle types and in public buildings to estimate penetration or infiltration factors. A large fraction of the observed pollutant concentrations for on-road MEs, especially near diesel trucks, was unrelated to ambient measurements at nearby monitors. Comparisons of ME concentrations estimated using the median ME/ambient ratio versus regression slopes and intercepts indicate that the regression approach may be more accurate for on-road MEs. Ranges in the ME/ambient ratios among ME categories were generally

  19. Air Pollution in China: Mapping of Concentrations and Sources

    PubMed Central

    Rohde, Robert A.; Muller, Richard A.

    2015-01-01

    China has recently made available hourly air pollution data from over 1500 sites, including airborne particulate matter (PM), SO2, NO2, and O3. We apply Kriging interpolation to four months of data to derive pollution maps for eastern China. Consistent with prior findings, the greatest pollution occurs in the east, but significant levels are widespread across northern and central China and are not limited to major cities or geologic basins. Sources of pollution are widespread, but are particularly intense in a northeast corridor that extends from near Shanghai to north of Beijing. During our analysis period, 92% of the population of China experienced >120 hours of unhealthy air (US EPA standard), and 38% experienced average concentrations that were unhealthy. China’s population-weighted average exposure to PM2.5 was 52 μg/m3. The observed air pollution is calculated to contribute to 1.6 million deaths/year in China [0.7–2.2 million deaths/year at 95% confidence], roughly 17% of all deaths in China. PMID:26291610

  20. Air Pollution in China: Mapping of Concentrations and Sources.

    PubMed

    Rohde, Robert A; Muller, Richard A

    2015-01-01

    China has recently made available hourly air pollution data from over 1500 sites, including airborne particulate matter (PM), SO2, NO2, and O3. We apply Kriging interpolation to four months of data to derive pollution maps for eastern China. Consistent with prior findings, the greatest pollution occurs in the east, but significant levels are widespread across northern and central China and are not limited to major cities or geologic basins. Sources of pollution are widespread, but are particularly intense in a northeast corridor that extends from near Shanghai to north of Beijing. During our analysis period, 92% of the population of China experienced >120 hours of unhealthy air (US EPA standard), and 38% experienced average concentrations that were unhealthy. China's population-weighted average exposure to PM2.5 was 52 μg/m3. The observed air pollution is calculated to contribute to 1.6 million deaths/year in China [0.7-2.2 million deaths/year at 95% confidence], roughly 17% of all deaths in China.

  1. Assessment of workplace air concentrations of formaldehyde during and before working hours in medical facilities

    PubMed Central

    HIGASHIKUBO, Ichiro; MIYAUCHI, Hiroyuki; YOSHIDA, Satoru; TANAKA, Shinsuke; MATSUOKA, Mitsunori; ARITO, Heihachiro; ARAKI, Akihiro; SHIMIZU, Hidesuke; SAKURAI, Haruhiko

    2017-01-01

    Workplace air concentrations of formaldehyde (FA) in medical facilities where FA and FA-treated organs were stored and handled were measured before and during working hours and assessed by the official method specified by Work Environment Measurement Law. Sixty-percent of the total facilities examined were judged as inappropriately controlled work environment. The concentrations of FA before working hours by spot sampling were found to exceed 0.1 ppm in some facilities, and tended to increase with increasing volume of containers storing FA and FA-treated materials. Regression analysis revealed that logarithmic concentrations of FA during working hours by the Law-specified analytical method were highly correlated with those before working hours by spot sampling, suggesting the importance for appropriate storing methods of FA and FA-treated materials. The concentrations of FA during working hours are considered to be lowered by effective ventilation of FA-contaminated workplace air and appropriate storage of FA and FA-treated materials in plastic containers in the medical facilities. In particular, such improvement by a local exhaust ventilation system and tightly-sealed containment of FA-treated material were urgently needed for the dissecting room where FA-treated cadavers were prepared and handled for a gross anatomy course in a medical school. PMID:28090065

  2. 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.

  3. CAirTOX, An inter-media transfer model for assessing indirect exposures to hazardous air contaminants

    SciTech Connect

    McKone, T.E.

    1994-01-01

    Risk assessment is a quantitative evaluation of information on potential health hazards of environmental contaminants and the extent of human exposure to these contaminants. As applied to toxic chemical emissions to air, risk assessment involves four interrelated steps. These are (1) determination of source concentrations or emission characteristics, (2) exposure assessment, (3) toxicity assessment, and (4) risk characterization. These steps can be carried out with assistance from analytical models in order to estimate the potential risk associated with existing and future releases. CAirTOX has been developed as a spreadsheet model to assist in making these types of calculations. CAirTOX follows an approach that has been incorporated into the CalTOX model, which was developed for the California Department of Toxic Substances Control, With CAirTOX, we can address how contaminants released to an air basin can lead to contamination of soil, food, surface water, and sediments. The modeling effort includes a multimedia transport and transformation model, exposure scenario models, and efforts to quantify uncertainty in multimedia, multiple-pathway exposure assessments. The capacity to explicitly address uncertainty has been incorporated into the model in two ways. First, the spreadsheet form of the model makes it compatible with Monte-Carlo add-on programs that are available for uncertainty analysis. Second, all model inputs are specified in terms of an arithmetic mean and coefficient of variation so that uncertainty analyses can be carried out.

  4. Reproducibility of measurements of trace gas concentrations in expired air.

    PubMed

    Strocchi, A; Ellis, C; Levitt, M D

    1991-07-01

    Measurement of the pulmonary excretion of trace gases has been used as a simple means of assessing metabolic reactions. End alveolar trace gas concentration, rather than excretory rate, is usually measured. However, the reproducibility of this measurement has received little attention. In 17 healthy subjects, duplicate collections of alveolar air were obtained within 1 minute of each other using a commercially available alveolar air sampler. The concentrations of hydrogen, methane, carbon monoxide, and carbon dioxide were measured. When the subject received no instruction on how to expire into the device, a difference of 28% +/- 19% (1SD) was found between duplicate determinations of hydrogen. Instructing the subjects to avoid hyperventilation or to inspire maximally and exhale immediately resulted in only minor reduction in variability. However, a maximal inspiration held for 15 seconds before exhalation reduced the difference to a mean of 9.6% +/- 8.0%, less than half that observed with the other expiratory techniques. Percentage difference of methane measurements with the four different expiratory techniques yielded results comparable to those obtained for hydrogen. In contrast, percentage differences for carbon monoxide measurements were similar for all expiratory techniques. When normalized to a PCO2 of 5%, the variability of hydrogen measurements with the breath-holding technique was reduced to 6.8% +/- 4.7%, a value significantly lower than that obtained with the other expiratory methods. This study suggests that attention to the expiratory technique could improve the accuracy of tests using breath hydrogen measurements.

  5. Concentrations of contaminants in muscle of the American alligator in Florida

    SciTech Connect

    Delany, M.F.; Bell, J.U.; Sundlof, S.F.

    1988-01-01

    Samples of tail muscle from 32 American alligators (Alligator mississippiensis) in Florida were analyzed for contaminant concentrations to provide preliminary information on the potential public health hazard of meat consumption. Detectable levels were found for eight metals; copper, zinc, iron, chromium, mercury, lead, cadmium and arsenic. Mean residue was highest for mercury (geometric mean = 0.61 ppm). DDE, DDD, DDT, dieldrin, heptachlor epoxide, lindane, and PCB's were found. Mean residue concentrations were compared by lake. Alligators appeared to be suitable monitors of environmental pollution. Concentrations of contaminants found in these animals probably pose little threat to public health. However, recommendations must await analysis of larger sample sizes and information on amount and frequency of meat consumption. Alligators killed for human consumption should continue to be monitored for contaminant residues.

  6. INTEGRATION OF PHOTOCATALYTIC OXIDATION WITH AIR STRIPPING OF CONTAMINATED AQUIFERS

    EPA Science Inventory

    Bench scale laboratory studies and pilot scale studies in a simulated field-test situation were performed to evaluate the integration of gas-solid ultaviolet (UV) photocatalytic oxidation (PCO) downstream if an air stripper unit as a technology for cost-effectively treating water...

  7. Passive sampling methods for contaminated sediments: scientific rationale supporting use of freely dissolved concentrations.

    PubMed

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

    2014-04-01

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

  8. A critical review of reported air concentrations of organic compounds in aircraft cabins.

    PubMed

    Nagda, N L; Rector, H E

    2003-09-01

    This paper presents a review and assessment of aircraft cabin air quality studies with measured levels of volatile and semivolatile organic compounds (VOCs and SVOCs). VOC and SVOC concentrations reported for aircraft cabins are compared with those reported for residential and office buildings and for passenger compartments of other types of transportation. An assessment of measurement technologies and quality assurance procedures is included. The six studies reviewed in the paper range in coverage from two to about 30 flights per study. None of the monitored flights included any unusual or episodic events that could affect cabin air quality. Most studies have used scientifically sound methods for measurements. Study results indicate that under routine aircraft operations, contaminant levels in aircraft cabins are similar to those in residential and office buildings, with two exceptions: (1). levels of ethanol and acetone, indicators of bioeffluents and chemicals from consumer products are higher in aircraft than in home or office environments, and (2). levels of certain chlorinated hydrocarbons and fuel-related contaminants are higher in residential/office buildings than in aircraft. Similarly, ethanol and acetone levels are higher in aircraft than in other transportation modes but the levels of some pollutants, such as m-/p-xylenes, tend to be lower in aircraft.

  9. Gas-Phase Ambient Air Contaminants Exhibit Significant Dioxin-like and Estrogen-like Activity in Vitro

    PubMed Central

    Klein, Gail P.; Hodge, Erin M.; Diamond, Miriam L.; Yip, Amelia; Dann, Tom; Stern, Gary; Denison, Michael S.; Harper, Patricia A.

    2006-01-01

    Several adverse health effects, such as respiratory and cardiovascular morbidity, have been linked to exposure to particulate matter in ambient air; however, the biologic activity of gas-phase ambient organic air contaminants has not been examined as thoroughly. Using aryl hydrocarbon receptor (AHR)–based and estrogen receptor (ER)–based cell bioassay systems, we assessed the dioxin-like and estrogenic activities of gas-phase organic ambient air contaminants compared with those of particulate-phase contaminants using samples collected between seasons over 2 years from an urban and a rural location in the Greater Toronto Area, Canada. The concentration of the sum (∑) of polycyclic aromatic hydrocarbons, which was highest in the gas phase, was 10–100 times more abundant than that of ∑polychlorinated biphenyls, ∑nitro-polycyclic aromatic hydrocarbons, and ∑organochlorine pesticides, and 103 to 104 times more abundant than ∑polychlorinated dibenzo-p-dioxins/dibenzofurans. Gas-phase samples induced significant AHR- and ER-dependent gene expression. The activity of the gas-phase samples was greater than that of the particulate-phase samples in the estrogen assay and, in one case, in the AHR assay. We found no strong associations between either summer or winter seasons or urban or rural locations in the relative efficacy of the extracts in either the ER or AHR assay despite differences in chemical composition, concentrations, and abundance. Our results suggest that mechanistic studies of the health effects of ambient air must consider gas and particulate phases because chemicals present in both phases can affect AHR and ER signaling pathways. PMID:16675423

  10. Organophosphates in aircraft cabin and cockpit air--method development and measurements of contaminants.

    PubMed

    Solbu, Kasper; Daae, Hanne Line; Olsen, Raymond; Thorud, Syvert; Ellingsen, Dag Gunnar; Lindgren, Torsten; Bakke, Berit; Lundanes, Elsa; Molander, Paal

    2011-05-01

    Methods for measurements and the potential for occupational exposure to organophosphates (OPs) originating from turbine and hydraulic oils among flying personnel in the aviation industry are described. Different sampling methods were applied, including active within-day methods for OPs and VOCs, newly developed passive long-term sample methods (deposition of OPs to wipe surface areas and to activated charcoal cloths), and measurements of OPs in high-efficiency particulate air (HEPA) recirculation filters (n = 6). In total, 95 and 72 within-day OP and VOC samples, respectively, have been collected during 47 flights in six different models of turbine jet engine, propeller and helicopter aircrafts (n = 40). In general, the OP air levels from the within-day samples were low. The most relevant OP in this regard originating from turbine and engine oils, tricresyl phosphate (TCP), was detected in only 4% of the samples (min-max concentration during ground testing in an airplane that had experienced leakage of turbine oil with subsequent contamination of the cabin and cockpit air, was an order of magnitude higher as compared to after engine replacement (p = 0.02).

  11. Performance of an internal-loop airlift bioreactor for treatment of hexane-contaminated air.

    PubMed

    Oliveira, Fernando J S; de França, Francisca P

    2005-01-01

    Hexane is a toxic volatile organic compound that is quite abundant in gas emissions from chemical industries and printing press and painting centers, and it is necessary to treat these airstreams before they discharge into the atmosphere. This article presents a treatment for hexane-contaminated air in steady-state conditions using an internal-loop airlift bioreactor inoculated with a Pseudomonas aeruginosa strain. Bioprocesses were conducted at 20-mL/min, a load of 1.26 gm3 of C6H14, and a temperature of 28 degrees C. The results of hexane removal efficiencies were presented as a function of the inoculum size (approx 0.07 and 0.2 g/L) and cell reuse. Bioprocess monitoring comprises quantification of the biomass, the surface tension of the medium, and the hexane concentration in the fermentation medium as well as in the inlet and outlet airstreams. The steady-state results suggest that the variation in inoculum size from 0.07 to 0.2 g/L promotes hexane abatement from the influent from 65 to 85%, respectively. Total hydrocarbon removal from the waste gas was achieved during experiments conducted using reused cells at an initial microbial concentration of 0.2 g/L.

  12. 10 CFR 835.209 - Concentrations of radioactive material in air.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 4 2013-01-01 2013-01-01 false Concentrations of radioactive material in air. 835.209... External Exposure § 835.209 Concentrations of radioactive material in air. (a) The derived air concentration (DAC) values given in appendices A and C of this part shall be used in the control of...

  13. 10 CFR 835.209 - Concentrations of radioactive material in air.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 4 2014-01-01 2014-01-01 false Concentrations of radioactive material in air. 835.209... External Exposure § 835.209 Concentrations of radioactive material in air. (a) The derived air concentration (DAC) values given in appendices A and C of this part shall be used in the control of...

  14. 10 CFR 835.209 - Concentrations of radioactive material in air.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 4 2011-01-01 2011-01-01 false Concentrations of radioactive material in air. 835.209... External Exposure § 835.209 Concentrations of radioactive material in air. (a) The derived air concentration (DAC) values given in appendices A and C of this part shall be used in the control of...

  15. 10 CFR 835.209 - Concentrations of radioactive material in air.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 4 2012-01-01 2012-01-01 false Concentrations of radioactive material in air. 835.209... External Exposure § 835.209 Concentrations of radioactive material in air. (a) The derived air concentration (DAC) values given in appendices A and C of this part shall be used in the control of...

  16. Enhancement of the microbial community biomass and diversity during air sparging bioremediation of a soil highly contaminated with kerosene and BTEX.

    PubMed

    Kabelitz, Nadja; Machackova, Jirina; Imfeld, Gwenaël; Brennerova, Maria; Pieper, Dietmar H; Heipieper, Hermann J; Junca, Howard

    2009-03-01

    In order to obtain insights in complexity shifts taking place in natural microbial communities under strong selective pressure, soils from a former air force base in the Czech Republic, highly contaminated with jet fuel and at different stages of a bioremediation air sparging treatment, were analyzed. By tracking phospholipid fatty acids and 16S rRNA genes, a detailed monitoring of the changes in quantities and composition of the microbial communities developed at different stages of the bioventing treatment progress was performed. Depending on the length of the air sparging treatment that led to a significant reduction in the contamination level, we observed a clear shift in the soil microbial community being dominated by Pseudomonads under the harsh conditions of high aromatic contamination to a status of low aromatic concentrations, increased biomass content, and a complex composition with diverse bacterial taxonomical branches.

  17. [Quality of interior air: biological contaminants and their effects on health; bioaerosols and gathering techniques].

    PubMed

    Bălan, Gabriela

    2007-01-01

    Indoor Air Quality: biological contaminants and health effects; airborne organisms and sampling instruments. Biological contaminants include bacteria, molds, viruses, animal dander and cat saliva, house dust, mites, cockroaches and pollen. Symptoms of health problems caused by biological pollutants include sneezing, watery eyes, coughing, shortness of breath, dizziness, lethargy, fevers. Children, elderly people with breathing problems, allergies and lung diseases are particularly susceptible to disease-causing biological agents in the indoor air. It is convenient to consider microbiological samplers for collecting organisms in air as falling into several broad categories. Many popular microbiological air samplers use the principle of impaction to trap the organisms by impacting them directly on to agar. Further distinct groups are the impingers, which operate by impinging organisms into liquid.

  18. Mercury Concentrations in Birds from Two Atmospherically Contaminated Sites in North Texas, USA.

    PubMed

    Schulwitz, Sarah E; Chumchal, Matthew M; Johnson, Jeff A

    2015-11-01

    Mercury (Hg) is a ubiquitous and highly toxic contaminant that can have negative effects on wildlife. Only a few studies have measured Hg concentrations in birds from the south central United States, and the potential threat of Hg contamination to birds in this region is largely unknown. In the present study, we assess Hg concentrations in blood and feathers from five bird species [eastern bluebird (Sialis sialis), Carolina wren (Thryothorus ludovicianus), wood duck (Aix sponsa), great egret (Ardea alba), and great blue heron (Ardea herodias)] that occupy different trophic levels at Caddo Lake and Lewisville Lake, located in northeast and north central Texas, respectively. Both sites are contaminated with Hg from the atmosphere. Adult passerines had higher Hg concentrations in their blood than conspecific nestlings. Mercury concentrations in feathers differed between species by more than an order of magnitude with large piscivorous species having higher concentrations than smaller insectivorous species. Mercury concentrations in eastern bluebirds were higher at Caddo Lake than Lewisville Lake. The present study represents one of the first studies of Hg concentrations in multiple bird species in north Texas and suggests that Hg concentrations in birds from atmospherically polluted sites in this region may be high enough to compromise fitness in those species.

  19. Catalytic wet air oxidation of high concentration pharmaceutical wastewater.

    PubMed

    Zhan, Wei; Wang, Xiaocong; Li, Daosheng; Ren, Yongzheng; Liu, Dongqi; Kang, Jianxiong

    2013-01-01

    In this study, we investigated the pretreatment of a high concentration pharmaceutical wastewater by catalytic wet air oxidation (CWAO) process. Different experiments were conducted to investigate the effects of the catalyst type, operating temperature, initial system pH, and oxygen partial pressure on the oxidation of the wastewater. Results show that the catalysts prepared by the co-precipitation method have better catalytic activity compared to others. Chemical oxygen demand (COD) conversion increased with the increase in temperature from 160 to 220 °C and decreased with the increase in pH. Moreover, the effect of the oxygen partial pressure on the COD conversion was significant only during the first 20 min of the reaction. Furthermore, the biodegradability of the wastewater improved greatly after CWAO, the ratio of BOD5/COD increased less than 0.1-0.75 when treated at 220 °C (BOD: biochemical oxygen demand).

  20. Circumpolar contaminant concentrations in polar bears (Ursus maritimus) and potential population-level effects.

    PubMed

    Nuijten, R J M; Hendriks, A J; Jenssen, B M; Schipper, A M

    2016-11-01

    Polar bears (Ursus maritimus) currently receive much attention in the context of global climate change. However, there are other stressors that might threaten the viability of polar bear populations as well, such as exposure to anthropogenic pollutants. Lipophilic organic compounds bio-accumulate and bio-magnify in the food chain, leading to high concentrations at the level of top-predators. In Arctic wildlife, including the polar bear, various adverse health effects have been related to internal concentrations of commercially used anthropogenic chemicals like PCB and DDT. The extent to which these individual health effects are associated to population-level effects is, however, unknown. In this study we assembled data on adipose tissue concentrations of ∑PCB, ∑DDT, dieldrin and ∑PBDE in individual polar bears from peer-reviewed scientific literature. Data were available for 14 out of the 19 subpopulations. We found that internal concentrations of these contaminants exceed threshold values for adverse individual health effects in several subpopulations. In an exploratory regression analysis we identified a clear negative correlation between polar bear population density and sub-population specific contaminant concentrations in adipose tissue. The results suggest that adverse health effects of contaminants in individual polar bears may scale up to population-level consequences. Our study highlights the need to consider contaminant exposure along with other threats in polar bear population viability analyses.

  1. Trace contaminant concentration affects mineral transformation and pollutant fate in hydroxide-weathered Hanford sediments.

    PubMed

    Perdrial, Nicolas; Rivera, Nelson; Thompson, Aaron; O'Day, Peggy A; Chorover, Jon

    2011-12-15

    Prior work has shown that when silicaceous sediments are infused with caustic radioactive waste, contaminant fate is tightly coupled to ensuing mineral weathering reactions. However, the effects of local aqueous geochemical conditions on these reactions are poorly studied. Thus, we varied contaminant concentration and pCO(2) during the weathering of previously uncontaminated Hanford sediments over 6 months and 1 year in a solution of caustic waste (pH 13, high ionic strength). Co-contaminants Sr, Cs and I were added at "low" (Cs/Sr: 10(-5)m; I: 10(-7)m) and "high" (Cs/Sr: 10(-3)m; I: 10(-5)m) concentrations, and headspace was held at atmospheric or undetectable (<10ppmv) CO(2) partial pressure. Solid phase characterization revealed the formation of the zeolite chabazite in "high" samples, whereas feldspathoids, sodalite and cancrinite, were formed preferentially in "low" samples. Sr, Cs and I were sequestered in all reacted sediments. Native calcite dissolution in the CO(2)-free treatment drove the formation of strätlingite (Ca(2)Al(2)SiO(7)·8H(2)O) and diminished availability of Si and Al for feldspathoid formation. Results indicate that pCO(2) and contaminant concentrations strongly affect contaminant speciation in waste-weathered sediments, and are therefore likely to impact reaction product stability under any remediation scenario.

  2. Maternal transfer of contaminants in birds: Mercury and selenium concentrations in parents and their eggs.

    PubMed

    Ackerman, Joshua T; Eagles-Smith, Collin A; Herzog, Mark P; Hartman, C Alex

    2016-03-01

    We conducted a detailed assessment of the maternal transfer of mercury and selenium to eggs in three bird species (n = 107 parents and n = 339 eggs), and developed predictive equations linking contaminant concentrations in eggs to those in six tissues of the mother (blood, muscle, liver, kidney, breast feathers, and head feathers). Mercury concentrations in eggs were positively correlated with mercury concentrations in each of the mother's internal tissues (R(2) ≥ 0.95), but generally not with feathers. For each species, the proportion of mercury transferred to eggs decreased as mercury concentrations in the mother increased. At the same maternal mercury concentration, the proportion of mercury transferred to eggs differed among species, such that Forster's tern (Sterna forsteri) and black-necked stilt (Himantopus mexicanus) females transferred more methylmercury to their eggs than American avocet (Recurvirostra americana) females. Selenium concentrations in eggs also were correlated with selenium concentrations in the mother's liver (R(2) = 0.87). Furthermore, mercury and selenium concentrations in tern eggs were positively correlated with those in the father (R(2) = 0.84). Incubating male terns had 21% higher mercury concentrations in blood compared to incubating females at the same egg mercury concentration. We provide equations to predict contaminant concentrations in eggs from each of the commonly sampled bird tissues.

  3. Maternal transfer of contaminants in birds: Mercury and selenium concentrations in parents and their eggs

    USGS Publications Warehouse

    Ackerman, Joshua T.; Eagles-Smith, Collin A.; Herzog, Mark P.; Hartman, C. Alex

    2016-01-01

    We conducted a detailed assessment of the maternal transfer of mercury and selenium to eggs in three bird species (n = 107 parents and n = 339 eggs), and developed predictive equations linking contaminant concentrations in eggs to those in six tissues of the mother (blood, muscle, liver, kidney, breast feathers, and head feathers). Mercury concentrations in eggs were positively correlated with mercury concentrations in each of the mother's internal tissues (R2 ≥ 0.95), but generally not with feathers. For each species, the proportion of mercury transferred to eggs decreased as mercury concentrations in the mother increased. At the same maternal mercury concentration, the proportion of mercury transferred to eggs differed among species, such that Forster's tern (Sterna forsteri) and black-necked stilt (Himantopus mexicanus) females transferred more methylmercury to their eggs than American avocet (Recurvirostra americana) females. Selenium concentrations in eggs also were correlated with selenium concentrations in the mother's liver (R2 = 0.87). Furthermore, mercury and selenium concentrations in tern eggs were positively correlated with those in the father (R2 = 0.84). Incubating male terns had 21% higher mercury concentrations in blood compared to incubating females at the same egg mercury concentration. We provide equations to predict contaminant concentrations in eggs from each of the commonly sampled bird tissues.

  4. Measurement of 16 volatile organic compounds in restaurant air contaminated with environmental tobacco smoke.

    PubMed

    Vainiotalo, S; Väänänen, V; Vaaranrinta, R

    2008-11-01

    Tobacco smoke-related air pollutant levels were studied in ten Finnish restaurants. Markers of tobacco smoke were measured together with other compounds typical of tobacco smoke and indoor air. The measurements were carried out at stationary sampling points in smoking and non-smoking areas of the restaurants in 2005-2006, when at least half of the service area had to be non-smoking according to the Finnish Tobacco Act. The average concentrations (geometric mean, microg/m3) of the 16 airborne contaminants measured in the smoking area were: nicotine 18.1; toluene 10.6; isoprene 10.2; m,p-xylene 5.0; limonene 4.8; benzene 3.3; furfuryl aldehyde 3.2; 1,3-butadiene 2.7; 3-ethenylpyridine (3-EP) 2.5; phenol 2.1; ethyl benzene 1.7; pyridine 1.6; o-xylene 1.5; 3-picoline 1.4; styrene 1.2; and naphthalene 0.45. A good correlation (r=0.90-0.99, p<0.001) was obtained between tobacco-specific markers (3-EP and nicotine) and 1,3-butadiene, isoprene, pyridine, furfuryl aldehyde, 3-picoline, phenol, and styrene. A poor or no correlation (r=0.19-0.60) was obtained between 3-EP or nicotine and the rest of the compounds. The average concentrations of all compounds were significantly lower in the non-smoking area than in the smoking area (p<0.05). In the non-smoking area, the average concentration of 3-EP was 0.35 microg/m3 and that of nicotine 1.6 microg/m3. In three restaurants, the area design and ventilation were effective: the average level of 3-EP in the non-smoking section was <3% from that in the smoking section. In the other restaurants, tobacco smoke was spreading more freely and the corresponding value was 14-76%. A sensitive method was applied for the measurement of airborne 1,3-butadiene. The air samples were collected into Carbopack X adsorption tubes and analysed by thermal desorption/gas chromatography/mass selective detection. The precision of the method was 4.2% (at 100 ng/sample) and the limit of quantification 0.02 microg/m3.

  5. Assessment of concentrations and effects of organohalogen contaminants in a terrestrial passerine, the European starling.

    PubMed

    Eng, Margaret L; Williams, Tony D; Letcher, Robert J; Elliott, John E

    2014-03-01

    European starlings (Sturnus vulgaris) are a valuable model species for the assessment of concentrations and effects of environmental contaminants in terrestrial birds. Polybrominated diphenyl ethers (PBDEs) are found in birds throughout the world, but relatively little is known of their concentrations or effects in free-living terrestrial passerines. We used a nest box population of European starlings to 1) measure the variation in egg concentrations of persistent organohalogen contaminants at an agricultural site, and 2) assess whether individual variation in PBDE concentrations in eggs was related to reproductive parameters, as well as maternal or nestling characteristics including body condition, thyroid hormones, oxidative stress, and hematocrit. As PBDEs were the main contaminant class of interest, we only assessed a subset of eggs for other organohalogen contaminants to establish background concentrations. Exposure to organohalogen contaminants was extremely variable over this relatively small study area. Geometric mean wet weight concentrations (range in brackets) of the major contaminants were 36.5 (12-174) ng/g ΣDDT (n=6 eggs) and 10.9 (2-307) ng/g ΣPBDEs (n=14). ΣPCBs at 3.58 (1.5-6.4) ng/g (n=6) were lower and less variable. There were low levels of other organochlorine (OC) pesticides such as dieldrin (2.02 ng/g), chlordanes (1.11 ng/g) and chlorobenzenes (0.23 ng/g). The only form of DDT detected was p,p'-DDE. The congener profiles of PBDEs and PCBs reflect those of industrial mixtures (i.e. DE-71, Aroclors 1254, 1260 and 1262). For all of the contaminant classes, concentrations detected in eggs at our study site were below levels previously reported to cause effects. Due to small sample sizes, we did not assess the relationship between ΣPCBs or ΣOCs and adult or chick condition. We observed no correlative relationships between individual variation in PBDE concentrations in starling eggs and reproductive success, maternal condition, or nestling

  6. Air-Seawater Exchange of Organochlorine Pesticides along the Sediment Plume of a Large Contaminated River.

    PubMed

    Lin, Tian; Guo, Zhigang; Li, Yuanyuan; Nizzetto, Luca; Ma, Chuanliang; Chen, Yingjun

    2015-05-05

    Gaseous exchange fluxes of organochlorine pesticides (OCPs) across the air-water interface of the coastal East China Sea were determined in order to assess whether the contaminated plume of the Yangtze River could be an important regional source of OCPs to the atmosphere. Hexachlorocyclohexanes (HCHs), chlordane compounds (CHLs), and dichlorodiphenyltrichloroethanes (DDTs) were the most frequently detected OCPs in air and water. Air-water exchange was mainly characterized by net volatilization for all measured OCPs. The net gaseous exchange flux ranged 10-240 ng/(m2·day) for γ-HCH, 60-370 ng/(m2·day) for trans-CHL, 97-410 ng/(m2·day) for cis-CHL, and ∼0 (e.g., equilibrium) to 490 ng/(m2·day) for p,p'-DDE. We found that the plume of the large contaminated river can serve as a significant regional secondary atmospheric source of legacy contaminants released in the catchment. In particular, the sediment plume represented the relevant source of DDT compounds (especially p,p'-DDE) sustaining net degassing when clean air masses from the open ocean reached the plume area. In contrast, a mass balance showed that, for HCHs, contaminated river discharge (water and sediment) plumes were capable of sustaining volatilization throughout the year. These results demonstrate the inconsistencies in the fate of HCHs and DDTs in this large estuarine system with declining primary sources.

  7. Brazing retort manifold design concept may minimize air contamination and enhance uniform gas flow

    NASA Technical Reports Server (NTRS)

    Ruppe, E. P.

    1966-01-01

    Brazing retort manifold minimizes air contamination, prevents gas entrapment during purging, and provides uniform gas flow into the retort bell. The manifold is easily cleaned and turbulence within the bell is minimized because all manifold construction lies outside the main enclosure.

  8. (Environmental investigation of ground water contamination at Wright-Patterson Air Force Base, Ohio)

    SciTech Connect

    Not Available

    1992-03-01

    This report presents information related to the sampling of ground water at the Wright-Patterson Air Force Base. It is part of an investigation into possible ground water contamination. Information concerns well drilling/construction; x-ray diffraction and sampling; soil boring logs; and chain-of-custody records.

  9. Monitoring Trace Contaminants in Air Via Ion Trap Mass Spectrometry

    NASA Technical Reports Server (NTRS)

    Palmer, Peter T.; Karr, Dane; Pearson, Richard; Valero, Gustavo; Wong, Carla

    1995-01-01

    Recent passage of the Clean Air Act with its stricter regulation of toxic gas emissions, and the ever-growing number of applications which require faster turnaround times between sampling and analysis are two major factors which are helping to drive the development of new instrument technologies for in-situ, on-line, real-time monitoring. The ion trap, with its small size, excellent sensitivity, and tandem mass spectrometry capability is a rapidly evolving technology which is well-suited for these applications. In this paper, we describe the use of a commercial ion trap instrument for monitoring trace levels of chlorofluorocarbons (CFCs) and volatile organic compounds (VOCs) in air. A number of sample introduction devices including a direct transfer line interface, short column GC, and a cryotrapping interface are employed to achieve increasing levels of sensitivity. MS, MS/MS, and MS/MS/MS methods are compared to illustrate trade-offs between sensitivity and selectivity. Filtered Noise Field (FNF) technology is found to be an excellent means for achieving lower detection limits through selective storage of the ion(s) of interest during ionization. Figures of merit including typical sample sizes, detection limits, and response times are provided. The results indicate the potential of these techniques for atmospheric assessments, the High Speed Research Program, and advanced life support monitoring applications for NASA.

  10. Nowcasting and Forecasting Concentrations of Biological Contaminants at Beaches: A Feasibility and Case Study

    EPA Science Inventory

    Public concern over microbial contamination of recreational waters has increased in recent years. A common approach to evaluating beach water quality has been to use the persistence model which assumes that day-old monitoring results provide accurate estimates of current concentr...

  11. Role of lauric acid-potassium hydroxide concentration on bacterial contamination of spray washed broiler carcasses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A series of experiments were conducted to examine reductions in bacterial contamination of broiler carcasses washed in a spray cabinet with various concentrations of lauric acid (LA)-potassium hydroxide (KOH) solutions. Fifty eviscerated carcasses and 5 ceca were obtained from the processing line of...

  12. Bioremediation of a soil contaminated by hydrocarbon mixtures: the residual concentration problem.

    PubMed

    Nocentini, M; Pinelli, D; Fava, F

    2000-10-01

    The phenomenon of residual concentration was investigated in the aerobic biodegradation of three different petroleum commercial products (i.e., kerosene, diesel fuel and a lubricating mineral oil) in static microcosms. Two different soils exhibiting different physical-chemical characteristics were used (i.e., a biologically treated hydrocarbon-contaminated soil and a pristine soil). Residual concentrations were observed and a simple way to take this phenomenon into account was proposed.

  13. Analysis of groundwater contamination using concentration-time series recorded during an integral pumping test: bias introduced by strong concentration gradients within the plume.

    PubMed

    Zeru, Allelign; Schäfer, Gerhard

    2005-12-01

    When only few monitoring wells are available to assess the extent and level of groundwater contamination, inversion of concentration breakthrough curves acquired during an integral pumping test can be used as an alternative quantification method. The idea is to use concentration-time series recorded during integral pumping tests through an inversion technique to estimate contaminant mass fluxes crossing a control plane. In this paper, we examine how a longitudinal concentration gradient along a contaminant plume length scale affects the estimated inversed-concentration distribution and its associated mass flux. The analytically inversed-concentration distribution at the imaginary control plane (ICP) is compared to a numerically generated concentration distribution, treating the latter one as a "real contaminant plume" characterized by the presence of a longitudinal concentration gradient. It is found that the analytically inversed-concentration can lead to overestimation or underestimation of concentration distribution values depending on the transport time period and dispersivity values. At lower dispersivity values, with shorter transport time periods, the analytically inversed-concentration distribution overestimates the "real" concentration distribution. A better fit of the estimated concentration distribution to the "real" one is observed when the transport time period increases, i.e. when the advective front has already crossed the ICP. However, for higher dispersivity values, underestimation of the real concentration distribution is observed. Deviation of the inversed-concentration distribution from the "real" one is assessed for a site-specific concentration gradient term. A concentration gradient adjusted contaminant mass flux is thus formulated to evaluate groundwater contamination levels at a given time period through an ICP. This concentration gradient ratio can indicate whether the ICP is well positioned to evaluate accurately contaminant mass fluxes

  14. Concentration and toxicity of sea-surface contaminants in Puget Sound

    SciTech Connect

    Hardy, J.T.; Crecelius, E.A.; Kocan, R.

    1986-04-01

    The Marine Research Laboratory conducted studies during CY 1985 to evaluate the effects of sea-surface contamination on the reproductive success of a valued marine species. Microlayer and bulk water samples were collected from a rural bay, central Puget Sound, and three urban bays and analyzed for a number of metal and organic contaminants as well as for densities of neuston and plankton organisms. Fertilized neustonic eggs of sand sole (Psettichthys melanostictus) were exposed to the same microlayer samples during their first week of embryonic and larval development. Also, we evaluated the effects of microlayer extracts on the growth of trout cell cultures. Compared to rural sites, urban bays generally contained lower densities of neustonic flatfish eggs during the spawning season. Also, in contrast to the rural sites or the one central Puget Sound site, approximately half of the urban bay microlayer samples resulted in significant increases in embryo mortality (up to 100%), kyphosis (bent spine abnormalities) in hatched larvae, increased anaphase aberrations in developing embryos, and decreased trout cell growth. The toxic samples generally contained high concentrations of polycyclic aromatic and/or chlorinated hydrocarbons and/or potentially toxic metals. In some cases, concentrations of contaminants on the sea surface exceeded water-quality criteria by several orders of magnitude. Several samples of subsurface bulk water collected below highly contaminated surfaces showed no detectable contamination or toxicity.

  15. [Simulation on remediation of benzene contaminated groundwater by air sparging].

    PubMed

    Fan, Yan-Ling; Jiang, Lin; Zhang, Dan; Zhong, Mao-Sheng; Jia, Xiao-Yang

    2012-11-01

    Air sparging (AS) is one of the in situ remedial technologies which are used in groundwater remediation for pollutions with volatile organic compounds (VOCs). At present, the field design of air sparging system was mainly based on experience due to the lack of field data. In order to obtain rational design parameters, the TMVOC module in the Petrasim software package, combined with field test results on a coking plant in Beijing, is used to optimize the design parameters and simulate the remediation process. The pilot test showed that the optimal injection rate was 23.2 m3 x h(-1), while the optimal radius of influence (ROI) was 5 m. The simulation results revealed that the pressure response simulated by the model matched well with the field test results, which indicated a good representation of the simulation. The optimization results indicated that the optimal injection location was at the bottom of the aquifer. Furthermore, simulated at the optimized injection location, the optimal injection rate was 20 m3 x h(-1), which was in accordance with the field test result. Besides, 3 m was the optimal ROI, less than the field test results, and the main reason was that field test reflected the flow behavior at the upper space of groundwater and unsaturated area, in which the width of flow increased rapidly, and became bigger than the actual one. With the above optimized operation parameters, in addition to the hydro-geological parameters measured on site, the model simulation result revealed that 90 days were needed to remediate the benzene from 371 000 microg x L(-1) to 1 microg x L(-1) for the site, and that the opeation model in which the injection wells were progressively turned off once the groundwater around them was "clean" was better than the one in which all the wells were kept operating throughout the remediation process.

  16. Impact of water management practice scenarios on wastewater flow and contaminant concentration.

    PubMed

    Marleni, N; Gray, S; Sharma, A; Burn, S; Muttil, N

    2015-03-15

    Due to frequent droughts and rapid population growth in urban areas, the adoption of practices to reduce the usage of fresh water is on the rise. Reduction in usage of fresh water can be achieved through various local water management practices (WMP) such as Water Demand Management (WDM) and use of alternative water sources such as Greywater Recycling (GR) and Rainwater Harvesting (RH). While the positive effects of WMPs have been widely acknowledged, the implementation of WMPs is also likely to lower the wastewater flow and increase the concentration of contaminants in sewage. These in turn can lead to increases in sewer problems such as odour and corrosion. This paper analyses impacts of various WMP scenarios on wastewater flow and contaminant load. The Urban Volume and Quality (UVQ) model was used to simulate wastewater flow and the associated wastewater contaminants from different WMP scenarios. The wastewater parameters investigated were those which influence odour and corrosion problems in sewerage networks due to the formation of hydrogen sulphide. These parameters are: chemical oxygen demand (COD), nitrate (NO3(-)), sulphate (SO4(2-)), sulphide (S(2-)) and iron (Fe) that were contributed by the households (not including the biochemical process in sewer pipe). The results will help to quantify the impact of WMP scenarios on odour and corrosion in sewerage pipe networks. Results show that the implementation of a combination of WDM and GR had highly increased the concentration of all selected contaminant that triggered the formation of hydrogen sulphide, namely COD, sulphate and sulphide. On the other hand, the RH scenario had the least increase in the concentration of the contaminants, except iron concentrations. The increase in iron concentrations is actually beneficial because it inhibits the formation of hydrogen sulphide.

  17. A novel method for assessing the role of air in the microbiological contamination of poultry carcasses.

    PubMed

    Burfoot, D; Whyte, R T; Tinker, D B; Hall, K; Allen, V M

    2007-04-01

    This paper describes a novel method of measuring the contamination of raw foods with airborne bacteria during primary processing. To demonstrate the approach, this study aimed to quantify the role of airborne bacteria in the contamination of broiler chicken carcasses undergoing processing in an evisceration room. Settle plates and broiler carcasses were exposed to the evisceration room air or to ultra-clean air provided by a high efficiency particulate air (HEPA) unit located within the room. The use of ultra-clean air reduced the total aerobic counts on horizontal settle plates by 68-fold, and on vertical settle plates by 14-fold. The use of ultra-clean air had no significant effect on the total aerobic counts on carcasses as measured by sponging (3.5 log(10) CFU cm(-2)) or skin excision (4.0 log(10) CFU cm(-2)). The novel approach was able to show that the carcasses entering the room were so heavily contaminated that the airborne bacteria in the evisceration room contributed less than 1% of the total numbers of bacteria on the carcasses.

  18. Plant Mounds as Concentration and Stabilization Agents for Actinide Soil Contaminants in Nevada

    SciTech Connect

    D.S. Shafer; J. Gommes

    2009-02-03

    Plant mounds or blow-sand mounds are accumulations of soil particles and plant debris around the base of shrubs and are common features in deserts in the southwestern United States. An important factor in their formation is that shrubs create surface roughness that causes wind-suspended particles to be deposited and resist further suspension. Shrub mounds occur in some plant communities on the Nevada Test Site, the Nevada Test and Training Range (NTTR), and Tonopah Test Range (TTR), including areas of surface soil contamination from past nuclear testing. In the 1970s as part of early studies to understand properties of actinides in the environment, the Nevada Applied Ecology Group (NAEG) examined the accumulation of isotopes of Pu, 241Am, and U in plant mounds at safety experiment and storage-transportation test sites of nuclear devices. Although aerial concentrations of these contaminants were highest in the intershrub or desert pavement areas, the concentration in mounds were higher than in equal volumes of intershrub or desert pavement soil. The NAEG studies found the ratio of contaminant concentration of actinides in soil to be greater (1.6 to 2.0) in shrub mounds than in the surrounding areas of desert pavement. At Project 57 on the NTTR, 17 percent of the area was covered in mounds while at Clean Slate III on the TTR, 32 percent of the area was covered in mounds. If equivalent volumes of contaminated soil were compared between mounds and desert pavement areas at these sites, then the former might contain as much as 34 and 62 percent of the contaminant inventory, respectively. Not accounting for radionuclides associated with shrub mounds would cause the inventory of contaminants and potential exposure to be underestimated. In addition, preservation of shrub mounds could be important part of long-term stewardship if these sites are closed by fencing and posting with administrative controls.

  19. IMPACT OF AN OZONE GENERATOR AIR CLEANER ON STYRENE CONCENTRATIONS IN AN INDOOR AIR QUALITY RESEARCH CHAMBER

    EPA Science Inventory

    The paper gives results of an investigation of the impact of an ozone generator air cleaner on vapor-phase styrene concentrations in a full-scale indoor air quality test chamber. The time history of the concentrations of styrene and ozone is well predicted by a simulation model u...

  20. Utilization of air pollution control residues for the stabilization/solidification of trace element contaminated soil.

    PubMed

    Travar, I; Kihl, A; Kumpiene, J

    2015-12-01

    The aim of this study was to evaluate the stabilization/solidification (S/S) of trace element-contaminated soil using air pollution control residues (APCRs) prior to disposal in landfill sites. Two soil samples (with low and moderate concentrations of organic matter) were stabilized using three APCRs that originated from the incineration of municipal solid waste, bio-fuels and a mixture of coal and crushed olive kernels. Two APCR/soil mixtures were tested: 30% APCR/70% soil and 50% APCR/50% soil. A batch leaching test was used to study immobilization of As and co-occurring metals Cr, Cu, Pb and Zn. Solidification was evaluated by measuring the unconfined compression strength (UCS). Leaching of As was reduced by 39-93% in APCR/soil mixtures and decreased with increased amounts of added APCR. Immobilization of As positively correlated with the amount of Ca in the APCR and negatively with the amount of soil organic matter. According to geochemical modelling, the precipitation of calcium arsenate (Ca3(AsO4)2/4H2O) and incorporation of As in ettringite (Ca6Al2(SO4)3(OH)12 · 26H2O) in soil/APCR mixtures might explain the reduced leaching of As. A negative effect of the treatment was an increased leaching of Cu, Cr and dissolved organic carbon. Solidification of APCR/soil was considerably weakened by soil organic matter.

  1. Using long-term air monitoring of semi-volatile organic compounds to evaluate the uncertainty in polyurethane-disk passive sampler-derived air concentrations.

    PubMed

    Holt, Eva; Bohlin-Nizzetto, Pernilla; Borůvková, Jana; Harner, Tom; Kalina, Jiří; Melymuk, Lisa; Klánová, Jana

    2017-01-01

    Much effort has been made to standardise sampling procedures, laboratory analysis, data analysis, etc. for semi volatile organic contaminants (SVOCs). Yet there are some unresolved issues in regards to comparing measurements from one of the most commonly used passive samplers (PAS), the polyurethane foam (PUF) disk PAS (PUF-PAS), between monitoring networks or different studies. One such issue is that there is no universal means to derive a sampling rate (Rs) or to calculate air concentrations (Cair) from PUF-PAS measurements for SVOCs. Cair was calculated from PUF-PAS measurements from a long-term monitoring program at a site in central Europe applying current understanding of passive sampling theory coupled with a consideration for the sampling of particle associated compounds. Cair were assessed against concurrent active air sampler (AAS) measurements. Use of "site-based/sampler-specific" variables: Rs, calculated using a site calibration, provided similar results for most gas-phase SVOCs to air concentrations derived using "default" values (commonly accepted Rs). Individual monthly PUF-PAS-derived air concentrations for the majority of the target compounds were significantly different (Wilcoxon signed-rank (WSR) test; p < 0.05) to AAS regardless of the input values (site/sampler based or default) used to calculate them. However, annual average PUF-PAS-derived air concentrations were within the same order of magnitude as AAS measurements except for the particle-phase polycyclic aromatic hydrocarbons (PAHs). Underestimation of PUF-derived air concentrations for particle-phase PAHs was attributed to a potential overestimation of the particle infiltration into the PUF-PAS chamber and underestimation of the particle bound fraction of PAHs.

  2. Environmental contaminant concentrations in Canada goose (Branta canadensis) muscle: probabilistic risk assessment for human consumers.

    PubMed

    Horak, Katherine; Chipman, Richard; Murphy, Lisa; Johnston, John

    2014-09-01

    The issue of food insecurity affects millions of people in the United States every year. Often these people rely on soup kitchens, food banks, and shelters for proper meals, and these organizations often depend on donations to meet needs. One of the most limited food resources is meat. To help alleviate this problem, the U.S. Department of Agriculture Wildlife Services donates more than 60 tons of wild game (deer, moose, feral hogs, goats, geese, and ducks) to a variety of charitable organizations each year. Although commercially produced meat routinely undergoes screening for contaminants, potential exposure to environmental contaminants from eating wild game is not well characterized. In this study, the concentration of 17 contaminants of concern in the breast meat of wild geese was examined. These concentrations were then used in a probabilistic model to estimate potential risk associated with consumption of this meat. Based on model predictions, more than 99 % of all adults were below exposure limits for all of the compounds tested. For all consumer age classes modeled, consumption of wild goose meat may expose a small fraction of these populations to levels of lead higher than the recommended exposure limits. Similarly, mercury exposure was predicted to be higher than the recommended limits when the meat was served as steaks. This information about concentrations of contaminants of concern in goose meat and potential exposures associated with meat consumption based on probabilistic models will enable others to make informed decisions about the risks associated with the consumption of wild meat.

  3. 10 CFR 835.209 - Concentrations of radioactive material in air.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Concentrations of radioactive material in air. 835.209... External Exposure § 835.209 Concentrations of radioactive material in air. (a) The derived air... exposures to airborne radioactive material. (b) The estimation of internal dose shall be based on...

  4. Estimation of Contaminant Subslab Concentration in Vapor Intrusion Including Lateral Source-Building Separation.

    PubMed

    Yao, Yijun; Shen, Rui; Pennell, Kelly G; Suuberg, Eric M

    2013-08-01

    Most current vapor-intrusion screening models employ the assumption of a subsurface homogenous source distribution, and groundwater data obtained from nearby monitoring wells are usually taken to reflect the source concentration for several nearby buildings. This practice makes it necessary to consider the possible influence of lateral source-building separation. In this study, a new way to estimate subslab (nonbiodegradable) contaminant concentration is introduced that includes the influence of source offset with the help of a conformal transform technique. Results from this method are compared with those from a three-dimensional numerical model. Based on this newly developed method, a possible explanation is provided here for the great variation in the attenuation factors of the soil vapor concentrations of groundwater-to-subslab contaminants found in the EPA vapor-intrusion database.

  5. Estimation of Contaminant Subslab Concentration in Vapor Intrusion Including Lateral Source–Building Separation

    PubMed Central

    Yao, Yijun; Shen, Rui; Pennell, Kelly G.; Suuberg, Eric M.

    2014-01-01

    Most current vapor-intrusion screening models employ the assumption of a subsurface homogenous source distribution, and groundwater data obtained from nearby monitoring wells are usually taken to reflect the source concentration for several nearby buildings. This practice makes it necessary to consider the possible influence of lateral source–building separation. In this study, a new way to estimate subslab (nonbiodegradable) contaminant concentration is introduced that includes the influence of source offset with the help of a conformal transform technique. Results from this method are compared with those from a three-dimensional numerical model. Based on this newly developed method, a possible explanation is provided here for the great variation in the attenuation factors of the soil vapor concentrations of groundwater-to-subslab contaminants found in the EPA vapor-intrusion database. PMID:24795543

  6. Performance of Passive Samplers for Monitoring Estuarine Water Column Concentrations 1. Contaminants of Concern

    PubMed Central

    Perron, Monique M.; Burgess, Robert M.; Suuberg, Eric M.; Cantwell, Mark G.; Pennell, Kelly G.

    2014-01-01

    Contaminants enter marine and estuarine environments and pose a risk to human and ecological health. Recently, passive sampling devices have been utilized to estimate dissolved concentrations of COCs, such as polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). In the present study, the performance of three common passive samplers was evaluated for sampling PAHs and PCBs at several stations in the temperate estuary Narragansett Bay (Rhode Island, USA). Sampler polymers included polyethylene (PE), polydimethylsiloxane (PDMS) coated solid phase microextraction (SPME) fibers, and polyoxymethylene (POM). Dissolved concentrations of each contaminant were calculated using measured sampler concentrations adjusted for equilibrium conditions with performance reference compounds (PRCs) and chemical-specific partition coefficients derived in the laboratory. Despite differences in PE and POM sampler concentrations, calculated total dissolved concentrations ranged from 14–93 ng/L and 13–465 pg/L for PAHs and PCBs, respectively. Dissolved concentrations of PAHs were approximately three times greater based on POM compared to PE while dissolved concentrations of PCBs based on PE were approximately three times greater than POM. Concentrations in SPME were not reported due to the lack of detectable chemical in the amount of PDMS polymer deployed. Continued research is needed to improve and support PE and POM use for the routine monitoring of COCs. For example, a better understanding of the use of PRCs with POM is critically needed. PMID:23832638

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

    PubMed Central

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

    2014-01-01

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

  8. Characterization of the frequency and nature of bleed air contamination events in commercial aircraft.

    PubMed

    Shehadi, M; Jones, B; Hosni, M

    2016-06-01

    Contamination of the bleed air used to pressurize and ventilate aircraft cabins is of concern due to the potential health and safety hazards for passengers and crew. Databases from the Federal Aviation Administration, NASA, and other sources were examined in detail to determine the frequency of bleed air contamination incidents. The frequency was examined on an aircraft model basis with the intent of identifying aircraft make and models with elevated frequencies of contamination events. The reported results herein may help investigators to focus future studies of bleed air contamination incidents on smaller number of aircrafts. Incident frequency was normalized by the number of aircraft, number of flights, and flight hours for each model to account for the large variations in the number of aircraft of different models. The focus of the study was on aircraft models that are currently in service and are used by major airlines in the United States. Incidents examined in this study include those related to smoke, oil odors, fumes, and any symptom that might be related to exposure to such contamination, reported by crew members, between 2007 and 2012, for US-based carriers for domestic flights and all international flights that either originated or terminated in the US. In addition to the reported frequency of incidents for different aircraft models, the analysis attempted to identify propulsion engines and auxiliary power units associated with aircrafts that had higher frequencies of incidents. While substantial variations were found in frequency of incidents, it was found that the contamination events were widely distributed across nearly all common models of aircraft.

  9. Contamination of the turbine air chamber: a risk of cross infection.

    PubMed

    Checchi, L; Montebugnoli, L; Samaritani, S

    1998-08-01

    In the present work, we evaluated (a) the influx of contaminating fluid into the air chamber when a high-speed turbine stops rotating, (b) the significance of a series of variables (type of handpiece and dental unit, shape of the bur, number of stops set on the turbine) which condition it, and (c) the time required to expel the contaminating fluid from the turbine head. Results showed that contamination takes place every time the turbine stops rotating with the bur in contact with an external fluid. The main variable affecting the influx of contaminating fluid into the air chamber of the turbine head was represented by the shape of the bur (F=54.9; p<0.01). Another significant variable was the type of handpiece and dental unit (F=7.3; p<0.01). The number of stops set on the turbine was irrelevant (F=0.03; p=n.s.). The expulsion of the contaminant from the turbine head showed 2 different exponential rates: a very rapid-elimination phase within 30 s and a slow-elimination phase between 60 and 300 s. In order to remove over 99% of the contaminant from the air chamber, a turbine had to run for more than 4-7 min depending on the type of the handpiece. In conclusion, data from the present study suggest that a significant cross-infection potential exists with high-speed handpieces whenever they are only externally scrubbed and disinfected so the internal cleaning and sterilization between patients is mandatory. The practice of flushing by running the turbines between patients should be discouraged.

  10. Investigation of indoor air volatile organic compounds concentration levels in dental settings and some related methodological issues.

    PubMed

    Santarsiero, Anna; Fuselli, Sergio; Piermattei, Alessandro; Morlino, Roberta; De Blasio, Giorgia; De Felice, Marco; Ortolani, Emanuela

    2009-01-01

    The assessment of indoor air volatile organic compounds (VOCs) concentration levels in dental settings has a big health relevance for the potentially massive occupational exposure to a lot of diverse contaminants. The comparison of the VOCs profile relative to indoor conditions and to the corresponding outdoor concentrations, as well as the discovery of possible correlations between specific dental activities and VOCs concentration variations are of utmost importance for offering a reliable characterization of risk for dentists and dental staff health. In this study we review the most relevant environmental studies addressing the VOCs contamination level in dental settings. We analyze the methodological problems this kind of study must face and we report preliminary results of an indoor air investigation, carried out at dental hospital in Italy, the "Ospedale odontoiatrico George Eastman" of Rome, in which general lines for the analysis of dental settings in environmental terms are sketched. The aim of this work is to identify the kind of problems a typical enclosed (non-industrial) environment indoor air investigation has to cope with by means of the analysis of a case study.

  11. A METHOD OF ASSESSING AIR TOXICS CONCENTRATIONS IN URBAN AREAS USING MOBILE PLATFORM MEASUREMENTS

    EPA Science Inventory

    The objective of this paper is to demonstrate an approach to characterize the spatial variability in ambient air concentrations using mobile platform measurements. This approach may be useful for air toxic assessments in Environmental Justice applications, epidemiological studies...

  12. Concentration of contaminants in breeding bird eggs from the Colorado River Delta, Mexico.

    PubMed

    García-Hernández, Jaqueline; Sapozhnikova, Yelena V; Schlenk, Daniel; Mason, Andrew Z; Hinojosa-Huerta, Osvel; Rivera-Díaz, Juan José; Ramos-Delgado, Norma Alicia; Sánchez-Bon, Gerardo

    2006-06-01

    Organic contaminants (organochlorine [OC], organophosphorus [OP] pesticides and polychlorinated biphenyls [PCBs]), and metals (As, Cd, Hg, Pb, and Se) are a concern to avian health in the Colorado River delta, Mexico. We determined concentrations of contaminants in eggs of three breeding species of birds from the delta (mourning doves [Zenaida macroura], burrowing owls [Athene cunicularia], and marsh wrens [Cistothorus palustris]). We collected 27 eggs of mourning doves, eight eggs of burrowing owls, and 18 eggs of marsh wrens for analyses. Polychlorinated biphenyls, OC, and OP pesticides were analyzed by gas chromatography equipped with an electron capture detector, and metals were analyzed by inductively coupled plasma mass spectrometry. The non-ortho PCB congeners (PCB 77 and 126) were found in mourning dove and burrowing owl eggs at concentrations in which hatchability can be affected. Mean selenium concentration found in marsh wren eggs (5.6 microg/g dry wt) exceeded the level of concern. Arsenic and Cd were found at higher than normal concentrations, Hg concentrations did not exceed the level of concern in any of the species, and Pb concentrations were higher in eggs of species subject to hunting. With the exception of lead, marsh wren eggs contained the highest metal concentrations.

  13. Microbial succession in a compost-packed biofilter treating benzene-contaminated air.

    PubMed

    Borin, Sara; Marzorati, Massimo; Brusetti, Lorenzo; Zilli, Mario; Cherif, Hanene; Hassen, Abdennaceur; Converti, Attilio; Sorlini, Claudia; Daffonchio, Daniele

    2006-03-01

    Air artificially contaminated with increasing concentrations of benzene was treated in a laboratory scale compost-packed biofilter for 240 days with a removal efficiency of 81-100%. The bacterial community in the packing material (PM) at different heights of the biofilter was analysed every 60 days. Bacterial plate counts and ribosomal intergenic spacer analysis (RISA) of the isolated strains showed that the number of cultivable aerobic heterotrophic bacteria and the species diversity increased with benzene availability. Identification of the isolated species and the main bands in denaturing gradient gel electrophoresis (DGGE) profiles from total compost DNA during the treatment revealed that, at a relatively low volumetric benzene load (1.2< or =VBL< or =6.4 g m(-3) (PM) h(-1)), besides low G+C Gram positive bacteria, originally present in the packing compost, bacteroidetes and beta- and gamma-proteobacteria became detectable in the colonising population. At the VBL value (24.8 g m(-3) (PM) h(-1)) ensuring the maximum elimination capacity of the biofilter (20.1 g m(-3) (PM) h(-1)), strains affiliated to the genus Rhodococcus dominated the microflora, followed by beta-proteobacteria comprising the genera Bordetella and Neisseria. Under these conditions, more than 35% of the isolated strains were able to grow on benzene as the sole carbon source. Comparison of DGGE and automated RISA profiles of the total community and isolated strains showed that a complex bacterial succession occurred in the reactor in response to the increasing concentrations of the pollutant and that cultivable bacteria played a major role in benzene degradation under the adopted conditions.

  14. Identification of the source of PFOS and PFOA contamination at a military air base site.

    PubMed

    Arias E, Victor A; Mallavarapu, Megharaj; Naidu, Ravi

    2015-01-01

    Although the use of perfluorooctane sulfonic acid (PFOS)/perfluorooctanoic acid (PFOA)-based aqueous fire-fighting foams (AFFF) has been banned due to their persistence, bioaccumulation and toxicity to biota, PFOS and PFOA are still present at significant levels in the environment due to their past usage. This study investigated the reasons for detection of PFOS and PFOA in an evaporation pond used to collect the wastewater arising from fire-fighting exercises at a military air base despite the replacement of PFOS/PFOA-based foam with no PFOS/PFOA-foam about 6 years ago. Concentrations in the wastewater stored in this pond ranged from 3.6 to 9.7 mg/L for PFOS and between 0.6 and 1.7 mg/L for PFOA. The hypothesis tested in a laboratory study was that PFOS and PFOA have accumulated in the sediments of the pond and can be released into the main body of the water. Concentrations detected in the sediments were 38 and 0.3 mg/g for PFOS and PFOA, respectively. These values exceed the recently reported average global values for sediments (0.2-3.8 ng/g for PFOS and from 0.1 to 0.6 ng/g for PFOA) by a factor of several thousands. PFOS and PFOA distribution coefficients were derived for the organic content of the pond sediment (1.6%). Identification of the source of contamination and knowledge of the partition between soil and aqueous phases are vital first steps in developing a sustainable remediation technology to remove the source from the site. This study clearly suggests that unless the sediment is cleaned of PFOS/PFOA, these chemicals will continue to be detected for a long period in the pond water, with potential adverse impacts on the ecosystem.

  15. Concentration of Petroleum-Hydrocarbon Contamination Shapes Fungal Endophytic Community Structure in Plant Roots

    PubMed Central

    Bourdel, Guillaume; Roy-Bolduc, Alice; St-Arnaud, Marc; Hijri, Mohamed

    2016-01-01

    Plant-root inhabiting fungi are a universal phenomenon found in all ecosystems where plants are able to grow, even in harsh environments. Interactions between fungi and plant roots can vary widely from mutualism to parasitism depending on many parameters. The role of fungal endophytes in phytoremediation of polluted sites, and characterization of the endophytic diversity and community assemblages in contaminated areas remain largely unexplored. In this study, we investigated the composition of endophytic fungal communities in the roots of two plant species growing spontaneously in petroleum-contaminated sedimentation basins of a former petro-chemical plant. The three adjacent basins showed a highly heterogeneous pattern of pollutant concentrations. We combined a culture-based isolation approach with the pyrosequencing of fungal ITS ribosomal DNA. We selected two species, Eleocharis erythropoda Steud. and Populus balsamifera L., and sampled three individuals of each species from each of three adjacent basins, each with a different concentration of petroleum hydrocarbons. We found that contamination level significantly shaped endophytic fungal diversity and community composition in E. erythropoda, with only 9.9% of these fungal Operational Taxonomic Units (OTUs) retrieved in all three basins. However, fungal community structure associated with P. balsamifera remained unaffected by the contamination level with 28.2% of fungal OTUs shared among all three basins. This could be explained by the smaller differences of pollutant concentrations in the soil around our set of P. balsamifera sampless compared to that around our set of E. erythropoda samples. Our culture-based approach allowed isolation of 11 and 30 fungal endophytic species from surface-sterilized roots of E. erythropoda and P. balsamifera, respectively. These isolates were ribotyped using ITS, and all were found in pyrosequensing datasets. Our results demonstrate that extreme levels of pollution reduce fungal

  16. Storage of LWR spent fuel in air. Volume 3, Results from exposure of spent fuel to fluorine-contaminated air

    SciTech Connect

    Cunningham, M.E.; Thomas, L.E.

    1995-06-01

    The Behavior of Spent Fuel in Storage (BSFS) Project has conducted research to develop data on spent nuclear fuel (irradiated U0{sub 2}) that could be used to support design, licensing, and operation of dry storage installations. Test Series B conducted by the BSFS Project was designed as a long-term study of the oxidation of spent fuel exposed to air. It was discovered after the exposures were completed in September 1990 that the test specimens had been exposed to an atmosphere of bottled air contaminated with an unknown quantity of fluorine. This exposure resulted in the test specimens reacting with both the oxygen and the fluorine in the oven atmospheres. The apparent source of the fluorine was gamma radiation-induced chemical decomposition of the fluoro-elastomer gaskets used to seal the oven doors. This chemical decomposition apparently released hydrofluoric acid (HF) vapor into the oven atmospheres. Because the Test Series B specimens were exposed to a fluorine-contaminated oven atmosphere and reacted with the fluorine, it is recommended that the Test Series B data not be used to develop time-temperature limits for exposure of spent nuclear fuel to air. This report has been prepared to document Test Series B and present the collected data and observations.

  17. Bioremediation of pesticide-contaminated water resources: the challenge of low concentrations.

    PubMed

    Helbling, Damian E

    2015-06-01

    The use of pesticides in agricultural and urban environments has improved quality of life around the world. However, the resulting accumulation of pesticide residues in fresh water resources has negative effects on aquatic ecosystem and human health. Bioremediation has been proposed as an environmentally sound alternative for the remediation of pesticide-contaminated water resources, though full-scale implementation has thus far been limited. One major challenge that has impeded progress is the occurrence of pesticides at low concentrations. Recent research has improved our fundamental understanding of pesticide biodegradation processes occurring at low concentrations under a variety of environmental scenarios and is expected to contribute to the development of applied bioremediation strategies for pesticide-contaminated water resources.

  18. Applications of real-time PCR in the screening of platelet concentrates for bacterial contamination.

    PubMed

    Mohammadi, Tamimount; Savelkoul, Paul H M; Pietersz, Ruby N I; Reesink, Henk W

    2006-11-01

    Although there have been major improvements over the past few decades in detection methods for blood-borne infectious agents, platelet concentrates are still responsible for most cases of transfusion-transmitted bacterial infections. To date, real-time PCR is an indispensable tool in diagnostic laboratories to detect pathogens in a variety of biological samples. In this article, the applications of this powerful technique in the screening of platelet concentrates for bacterial contamination are discussed. Next to pathogen-specific (real-time) PCR assays, particular attention is directed to the recently developed 16S rDNA real-time PCR. This assay has been proven as a convenient way to detect bacterial contamination of platelet concentrates. The assay is sensitive and enables rapid detection of low initial numbers of bacteria in platelet concentrates. The short turnaround time of this assay allows high-throughput screening and reduction of the risk of transfusion of bacterially contaminated units. As with every method, real-time PCR has its advantages and disadvantages. These and especially limitations inherent to generation of false-positive or -negative results are emphasized. The universal nature of detection of the assay may be suitable for generalized bacterial screening of other blood components, such as red blood cells and plasma. Therefore, it is necessary to adapt and optimize detection in red blood cells and plasma with real-time PCR. Further sophistication, miniaturization and standardization of extraction and amplification methods should improve the total performance and robustness of the assay. Hence, real-time PCR is an attractive method in development as a more rapid screening test than currently used culture methods to detect bacterial contamination in blood components.

  19. Reactive Distillation and Air Stripping Processes for Water Recycling and Trace Contaminant Control

    NASA Technical Reports Server (NTRS)

    Boul, Peter J.; Lange, Kevin E.; Conger, Bruce; Anderson, Molly

    2009-01-01

    Reactive distillation designs are considered to reduce the presence of volatile organic compounds in the purified water. Reactive distillation integrates a reactor with a distillation column. A review of the literature in this field has revealed a variety of functional reactive columns in industry. Wastewater may be purified by a combination of a reactor and a distiller (e.g., the EWRS or VPCAR concepts) or, in principle, through a design which integrates the reactor with the distiller. A review of the literature in reactive distillation has identified some different designs in such combinations of reactor and distiller. An evaluation of reactive distillation and reactive air stripping is presented with regards to the reduction of volatile organic compounds in the contaminated water and air. Among the methods presented, an architecture is presented for the evaluation of the simultaneous oxidation of organics in air and water. These and other designs are presented in light of potential improvements in power consumptions and air and water purities for architectures which include catalytic activity integrated into the water processor. In particular, catalytic oxidation of organics may be useful as a tool to remove contaminants that more traditional distillation and/or air stripping columns may not remove. A review of the current leading edge at the commercial level and at the research frontier in catalytically active materials is presented. Themes and directions from the engineering developments in catalyst design are presented conceptually in light of developments in the nanoscale chemistry of a variety of catalyst materials.

  20. Use of inorganic dryer-salts in the determination of organic contaminants in air

    SciTech Connect

    Simonov, V.A.

    1985-09-01

    This paper presents results of a study of the adsorptive activity of a number of inorganic salts relative to water vapor and to organic vapors in air under the dynamic conditions which are uses in the indicator tube method. Data are also given on the properties of dryer salts having a surface modified with glycerin. It is shown that lithium chloride on porcelain and potassium carbonate having a surface modified with glycerin can be used to dry air in determining contaminants of nonpolar and polar organic substances in it. Anhydrone on porcelain, calcium chloride, and potassium carbonate absorb some substances which are being determined and therefore are less suitable.

  1. (Environmental investigation of ground water contamination at Wright- Patterson Air Force Base, Ohio)

    SciTech Connect

    Not Available

    1991-10-01

    This Health and Safety Plan (HSP) was developed for the Environmental Investigation of Ground-water Contamination Investigation at Wright-Patterson Air Force Base near Dayton, Ohio, based on the projected scope of work for the Phase 1, Task 4 Field Investigation. The HSP describes hazards that may be encountered during the investigation, assesses the hazards, and indicates what type of personal protective equipment is to be used for each task performed. The HSP also addresses the medical monitoring program, decontamination procedures, air monitoring, training, site control, accident prevention, and emergency response.

  2. Ion exchange membrane bioreactor for treating groundwater contaminated with high perchlorate concentrations.

    PubMed

    Fox, Shalom; Oren, Yoram; Ronen, Zeev; Gilron, Jack

    2014-01-15

    Perchlorate contamination of groundwater is a worldwide concern. The most cost efficient treatment for high concentrations is biological treatment. In order to improve and increase the acceptance of this treatment, there is a need to reduce the contact between micro organisms in the treatment unit and the final effluent. An ion exchange membrane bioreactor (IEMB), in which treated water is separated from the bioreactor, was suggested for this purpose. In this study, the IEMB's performance was studied at a concentration as high as 250mgL(-1) that were never studied before. In the bioreactor, glycerol was used as a low cost and nontoxic carbon and energy source for the reduction of perchlorate to chloride. We found that high perchlorate concentrations in the feed rendered the anion exchange membrane significantly less permeable to perchlorate. However, the presence of bacteria in the bio-compartment significantly increased the flux through the membrane by more than 25% in comparison to pure Donnan dialysis. In addition, the results suggested minimal secondary contamination (<3mgCL(-1)) of the treated water with the optimum feed of carbon substrate. Our results show that IEMB can efficiently treat groundwater contaminated with perchlorate as high as 250mgL(-1).

  3. Plasma flame for mass purification of contaminated air with chemical and biological warfare agents

    SciTech Connect

    Uhm, Han S.; Shin, Dong H.; Hong, Yong C.

    2006-09-18

    An elimination of airborne simulated chemical and biological warfare agents was carried out by making use of a plasma flame made of atmospheric plasma and a fuel-burning flame, which can purify the interior air of a large volume in isolated spaces such as buildings, public transportation systems, and military vehicles. The plasma flame generator consists of a microwave plasma torch connected in series to a fuel injector and a reaction chamber. For example, a reaction chamber, with the dimensions of a 22 cm diameter and 30 cm length, purifies an airflow rate of 5000 lpm contaminated with toluene (the simulated chemical agent) and soot from a diesel engine (the simulated aerosol for biological agents). Large volumes of purification by the plasma flame will free mankind from the threat of airborne warfare agents. The plasma flame may also effectively purify air that is contaminated with volatile organic compounds, in addition to eliminating soot from diesel engines as an environmental application.

  4. Plasma flame for mass purification of contaminated air with chemical and biological warfare agents

    NASA Astrophysics Data System (ADS)

    Uhm, Han S.; Shin, Dong H.; Hong, Yong C.

    2006-09-01

    An elimination of airborne simulated chemical and biological warfare agents was carried out by making use of a plasma flame made of atmospheric plasma and a fuel-burning flame, which can purify the interior air of a large volume in isolated spaces such as buildings, public transportation systems, and military vehicles. The plasma flame generator consists of a microwave plasma torch connected in series to a fuel injector and a reaction chamber. For example, a reaction chamber, with the dimensions of a 22cm diameter and 30cm length, purifies an airflow rate of 5000lpm contaminated with toluene (the simulated chemical agent) and soot from a diesel engine (the simulated aerosol for biological agents). Large volumes of purification by the plasma flame will free mankind from the threat of airborne warfare agents. The plasma flame may also effectively purify air that is contaminated with volatile organic compounds, in addition to eliminating soot from diesel engines as an environmental application.

  5. Atmospheric pressure discharge plasma decomposition for gaseous air contaminants -- Trichlorotrifluoroethane and trichloroethylene

    SciTech Connect

    Oda, Tetsuji; Yamashita, Ryuichi; Takahashi, Tadashi; Masuda, Senichi

    1996-03-01

    The decomposition performance of gaseous environmental destructive contaminants in air by using atmospheric pressure discharged plasma including the surface discharge induced plasma chemical processing (SPCP) was examined. The main contaminants tested were chlorofluorocarbon (CFC-113) and trichloroethylene, typically. The discharge exciting frequency range studied was wide--50 Hz to 50 kHz. Results showed the low frequency discharge requires high voltage to inject high electric power in the gas and to decompose the contaminants. A Gas Chromatograph Mass Spectrometer was used to analyze discharge products of dense CFC-113 or trichloroethylene. Among the detected products were HCl, CClFO, and CHCl{sub 3}. Two different electrode configurations; the silent discharge (coaxial) electrode and the coil-electrode were also tested and compared to each other as a gas reactor.

  6. Traffic in the operating room: a review of factors influencing air flow and surgical wound contamination.

    PubMed

    Pokrywka, Marian; Byers, Karin

    2013-06-01

    Surgical wound contamination leading to surgical site infection can result from disruption of the intended airflow in the operating room (OR). When personnel enter and exit the OR, or create unnecessary movement and traffic during the procedure, the intended airflow in the vicinity of the open wound becomes disrupted and does not adequately remove airborne contaminants from the sterile field. An increase in the bacterial counts of airborne microorganisms is noted during increased activity levels within the OR. Researchers have studied OR traffic and door openings as a determinant of air contamination. During a surgical procedure the door to the operating room may be open as long as 20 minutes out of each surgical hour during critical procedures involving implants. Interventions into limiting excessive movement and traffic in the OR may lead to reductions in surgical site infections in select populations.

  7. Nonlinear Least-Squares Based Method for Identifying and Quantifying Single and Mixed Contaminants in Air with an Electronic Nose

    PubMed Central

    Zhou, Hanying; Homer, Margie L.; Shevade, Abhijit V.; Ryan, Margaret A.

    2006-01-01

    The Jet Propulsion Laboratory has recently developed and built an electronic nose (ENose) using a polymer-carbon composite sensing array. This ENose is designed to be used for air quality monitoring in an enclosed space, and is designed to detect, identify and quantify common contaminants at concentrations in the parts-per-million range. Its capabilities were demonstrated in an experiment aboard the National Aeronautics and Space Administration's Space Shuttle Flight STS-95. This paper describes a modified nonlinear least-squares based algorithm developed to analyze data taken by the ENose, and its performance for the identification and quantification of single gases and binary mixtures of twelve target analytes in clean air. Results from laboratory-controlled events demonstrate the effectiveness of the algorithm to identify and quantify a gas event if concentration exceeds the ENose detection threshold. Results from the flight test demonstrate that the algorithm correctly identifies and quantifies all registered events (planned or unplanned, as singles or mixtures) with no false positives and no inconsistencies with the logged events and the independent analysis of air samples.

  8. Organochlorine pesticides in surface soils from obsolete pesticide dumping ground in Hyderabad City, Pakistan: contamination levels and their potential for air-soil exchange.

    PubMed

    Alamdar, Ambreen; Syed, Jabir Hussain; Malik, Riffat Naseem; Katsoyiannis, Athanasios; Liu, Junwen; Li, Jun; Zhang, Gan; Jones, Kevin C

    2014-02-01

    This study was conducted to examine organochlorine pesticides (OCPs) contamination levels in the surface soil and air samples together with air-soil exchange fluxes at an obsolete pesticide dumping ground and the associated areas from Hyderabad City, Pakistan. Among all the sampling sites, concentrations of OCPs in the soil and air samples were found highest in obsolete pesticide dumping ground, whereas dominant contaminants were dichlorodiphenyltrichloroethane (DDTs) (soil: 77-212,200 ng g(-1); air: 90,700 pg m(-3)) and hexachlorocyclohexane (HCHs) (soil: 43-4,090 ng g(-1); air: 97,400 pg m(-3)) followed by chlordane, heptachlor and hexachlorobenzene (HCB). OCPs diagnostic indicative ratios reflect historical use as well as fresh input in the study area. Moreover, the air and soil fugacity ratios (0.9-1.0) at the dumping ground reflecting a tendency towards net volatilization of OCPs, while at the other sampling sites, the fugacity ratios indicate in some cases deposition and in other cases volatilization. Elevated concentrations of DDTs and HCHs at pesticide dumping ground and its surroundings pose potential exposure risk to biological organisms, to the safety of agricultural products and to the human health. Our study thus emphasizes the need of spatio-temporal monitoring of OCPs at local and regional scale to assess and remediate the future adverse implications.

  9. Spatial uncoupling of biodegradation, soil respiration, and PAH concentration in a creosote contaminated soil.

    PubMed

    Bengtsson, Göran; Törneman, Niklas; Yang, Xiuhong

    2010-09-01

    Hotspots and coldspots of concentration and biodegradation of polycyclic aromatic hydrocarbons (PAHs) marginally overlapped at the 0.5-100 m scale in a creosote contaminated soil in southern Sweden, suggesting that concentration and biodegradation had little spatial co-variation. Biodegradation was substantial and its spatial variability considerable and highly irregular, but it had no spatial autocorrelation. The soil concentration of PAHs explained only 20-30% of the variance of their biodegradation. Soil respiration was spatially autocorrelated. The spatial uncoupling between biodegradation and soil respiration seemed to be governed by the aging of PAHs in the soil, since biodegradation of added 13C phenanthrene covaried with both soil respiration and microbial biomass. The latter two were also correlated with high concentrations of phospholipid fatty acids (PLFAs) that are common in gram-negative bacteria. However, several of the hotspots of biodegradation coincided with hotspots for the distribution of a PLFA indicative of fungal biomass.

  10. Arsenic concentrations and bacterial contamination in a pilot shallow dugwell program in West Bengal, India.

    PubMed

    Hira-Smith, Meera M; Yuan, Yan; Savarimuthu, Xavier; Liaw, Jane; Hira, Alpana; Green, Cynthia; Hore, Timir; Chakraborty, Protap; von Ehrenstein, Ondine S; Smith, Allan H

    2007-01-01

    Project Well has developed a pilot self-supporting community-based mitigation program to provide arsenic-safe water to the villagers of North 24 Parganas, West Bengal, India. Shallow concrete dugwells, less than 25 feet deep, that tap into an unconfined aquifer are constructed following stipulated guidelines. The design differs from the traditional dugwell in two major ways: (i) there is a layer of coarse sand in the annular space enveloping the outer wall of the concrete cylinder; and (ii) handpumps are used for water extraction to reduce the potential for bacterial contamination. Monitoring programs for arsenic and coliform bacteria in selected dugwells have been completed. In summer, when the water levels were low, the arsenic concentrations were measured. In 11 wells, measured over three years, the average water arsenic concentration was 29 micro gL-1. Two dugwells had high concentrations of arsenic (average 152 micro gL-1 and 61 micro gL-1), but the remaining nine dugwells had an overall average of 11 micro gL-1. Seasonal variation was assessed in five wells with monthly measurements and there was a direct relationship between increases in arsenic concentrations and decreases in the volume of water in the dugwells in the dry summer season. To control bacterial contamination, sodium hypochlorite solution containing 5% chlorine was applied once a month. In 2005, fecal coliform was undetected in 65% (n = 13) of the dugwells but detected at high levels in 35% (n = 7) of the dugwells. The program clearly reduced exposure to arsenic, but we conclude that further study of increases in arsenic concentrations in the dry season are warranted, as well as assessment of ways to more effectively control bacterial contamination such as more frequent chlorination, perhaps with lower doses on each occasion.

  11. Effective radium concentration in topsoils contaminated by lead and zinc smelters.

    PubMed

    Girault, Frédéric; Perrier, Frédéric; Poitou, Charles; Isambert, Aude; Théveniaut, Hervé; Laperche, Valérie; Clozel-Leloup, Blandine; Douay, Francis

    2016-10-01

    Trace elements (TE) are indicative of industrial pollution in soils, but geochemical methods are difficult to implement in contaminated sites with large numbers of samples. Therefore, measurement of soil magnetic susceptibility (MS) has been used to map TE pollutions, albeit with contrasted results in some cases. Effective radium concentration (ECRa), product of radium concentration by the emanation factor, can be measured in a cost-effective manner in the laboratory, and could then provide a useful addition. We evaluate this possibility using 186 topsoils sampled over about 783km(2) around two former lead and zinc smelters in Northern France. The ECRa values, obtained from 319 measurements, range from 0.70±0.06 to 12.53±0.49Bq·kg(-1), and are remarkably organized spatially, away from the smelters, in domains corresponding to geographical units. Lead-contaminated soils, with lead concentrations above 100mg·kg(-1) <3km from the smelters, are characterized on average by larger peak ECRa values and larger dispersion. At large scales, away from the smelters, spatial variations of ECRa correlate well with spatial variations of MS, thus suggesting that, at distance larger than 5km, variability of MS contains a significant natural component. Larger ECRa values are correlated with larger fine fraction and, possibly, mercury concentration. While MS is enhanced in the vicinity of the smelters and is associated with the presence of soft ferrimagnetic minerals such as magnetite, it does not correlate systematically with metal concentrations. When multiple industrial and urban sources are present, ECRa mapping, thus, can help in identifying at least part of the natural spatial variability of MS. More generally, this study shows that ECRa mapping provides an independent and reliable assessment of the background spatial structure which underlies the structure of a given contamination. Furthermore, ECRa may provide a novel index to identify soils potentially able to fix

  12. Determination of fecal contamination origin in reclaimed water open-air ponds using biochemical fingerprinting of enterococci and fecal coliforms.

    PubMed

    Casanovas-Massana, Arnau; Blanch, Anicet R

    2013-05-01

    Low levels of fecal indicator bacteria (FIB) were recently detected in two reclaimed water open-air ponds used to irrigate a golf course located in Northeastern Spain. The aim of this study was to evaluate the feasibility of a biochemical fingerprinting method to track the origin of fecal contamination in water with low FIB levels, as in the aforementioned ponds. We also aimed to determine whether FIB presence was due to regrowth of the reclaimed water populations or to a contribution of fecal matter whose source was in the golf facility. Three hundred and fifty enterococcal strains and 308 fecal coliform strains were isolated from the ponds and reclamation plant, and they were biochemically phenotyped. In addition, the inactivation of several microbial fecal pollution indicators (fecal coliforms, total bifidobacteria, sorbitol-fermenting bifidobacteria, somatic bacteriophages, and bacteriophages infecting Bacteroides thetaiotaomicron) was studied using a mesocosm in situ in order to obtain information about their decay rate. Although FIB concentration was low, the biochemical fingerprinting provided evidence that the origin of the fecal contamination in the ponds was not related to the reclaimed water. Biochemical fingerprinting thus proved to be a successful approach, since other microbial source-tracking methods perform poorly when dealing with low fecal load matrices. Furthermore, the mesocosm assays indicated that none of the microbial fecal indicators was able to regrow in the ponds. Finally, the study highlights the fact that reclaimed water may be recontaminated in open-air reservoirs, and therefore, its microbial quality should be monitored throughout its use.

  13. Remediation of oil-contaminated sand with self-collapsing air microbubbles.

    PubMed

    Agarwal, Ashutosh; Zhou, Yufeng; Liu, Yu

    2016-12-01

    In this study, a novel chemical-free approach for cleaning oil-contaminated sand with self-collapsing air microbubbles (MBs) with diameter less than 50 μm was developed without the use of chemicals, such as surfactants and alkalis. Diesel and rotary-vane pump oil-contaminated fine and medium sands were treated with MBs to study the effect of oil viscosity and sand grain size on oil removal with MBs. About 95 % of diesel removal was achieved for 24 h old 10 % (w/w) diesel-contaminated medium sand in contrast to only 70 % removal from fine sand after 40-min treatment with MBs. While rotary-vane pump oil removal exceeds that of diesel after 40-min treatment with MBs, combination of mechanical stirring with MBs significantly enhanced the oil removal rate, whereby 95 % diesel removal was achieved from fine sand in 30 min in contrast to only 52 % diesel removal with MBs alone. A possible MBs cleaning mechanism for oil-contaminated sand was also proposed. This study provides experimental evidence for the applicability of self-collapsing MBs as a novel chemical-free approach for cleaning oil-contaminated sand.

  14. The use of air fuel cell cathodes to remove contaminants from spent chromium plating solutions.

    PubMed

    Huang, K L; Holsen, T M; Chou, T C; Yang, M C

    2004-01-01

    Results from experiments using an impregnation-reduction (I-R) Pt / Nafion membrane electrode assembly (MEA) in an air fuel cell cathode to remove contaminants (Cu(II), Ni(II), and Fe(III)) from spent chromium electroplating baths are presented in this study. A platinum-carbon (Pt-C) / Nafion MEA and a Pb planar cathode were also used for comparison. The average removal rates of Cu(II) and Ni(II) were almost the same (0.39 and 0.40 mM hr(-1) (or 0.117 and 0.12 mmol hr(-1)), respectively) but higher than that of Fe(III) (0.16 mM hr(-1), or 0.048 mmol hr(-1)) in accordance with the Nernst-Planck flux equation. The removal rates for the same cation were independent of the cathode used. The average removal rate of each impurity was approximately proportional to the product of its initial concentration and separator area/anolyte volume ratio using Pb cathodes. Under constant current conditions the system using the Pt-C / Nafion cathode needed the highest cell voltage, about 3 V more than needed for the system with the Pt / Nafion cathode. The cell voltage required using the Pt / Nafion cathode was similar to that using the conventional planar Pb cathode. Analyses of cathode deposits by SEM/EDS and XPS techniques indicated they were minimal on the Pb and Pt / Nafion cathode and more apparent on the Pt-C / Nafion cathode. The primary deposits on the Pb cathode were chromium oxides (e.g., Cr2O3) with minor amount of lead chromate (lead dichromate or lead trichromate) and other chromium solids (Cr black). As expected, the dominant deposit on the lead anode surface was PbO2.

  15. Empirical model for estimating vertical concentration profiles of re-suspended, sediment-associated contaminants

    NASA Astrophysics Data System (ADS)

    Zhu, H. W.; Cheng, P. D.; Li, W.; Chen, J. H.; Pang, Y.; Wang, D. Z.

    2017-03-01

    Vertical distribution processes of sediment contaminants in water were studied by flume experiments. Experimental results show that settling velocity of sediment particles and turbulence characteristics are the major hydrodynamic factors impacting distribution of pollutants, especially near the bottom where particle diameter is similar in size to vortex structure. Sediment distribution was uniform along the distance, while contaminant distribution slightly lagged behind the sediment. The smaller the initial sediment concentration was, the more time it took to achieve a uniform concentration distribution for suspended sediment. A contaminants transportation equation was established depending on mass conservation equations. Two mathematical estimation models of pollutant distribution in the overlying water considering adsorption and desorption were devised based on vertical distribution of suspended sediment: equilibrium partition model and dynamic micro-diffusion model. The ratio of time scale between the sediment movement and sorption can be used as the index of the models. When this ratio was large, the equilibrium assumption was reasonable, but when it was small, it might require dynamic micro-diffusion model.

  16. The Potential Source of B. licheniformis Contamination During Whey Protein Concentrate 80 Manufacture.

    PubMed

    Md Zain, Siti Norbaizura; Bennett, Rod; Flint, Steve

    2017-03-01

    The objective of this study was to determine the possible source of predominant Bacillus licheniformis contamination in a whey protein concentrate (WPC) 80 manufacturing plant. Traditionally, microbial contaminants of WPC were believed to grow on the membrane surfaces of the ultrafiltration plant as this represents the largest surface area in the plant. Changes from hot to cold ultrafiltration have reduced the growth potential for bacteria on the membrane surfaces. Our recent studies of WPCs have shown the predominant microflora B. licheniformis would not grow in the membrane plant because of the low temperature (10 °C) and must be growing elsewhere. Contamination of dairy products is mostly due to bacteria being released from biofilm in the processing plant rather from the farm itself. Three different reconstituted WPC media at 1%, 5%, and 20% were used for biofilm growth and our results showed that B. licheniformis formed the best biofilm at 1% (low solids). Further investigations were done using 3 different media; tryptic soy broth, 1% reconstituted WPC80, and 1% reconstituted WPC80 enriched with lactose and minerals to examine biofilm growth of B. licheniformis on stainless steel. Thirty-three B. licheniformis isolates varied in their ability to form biofilm on stainless steel with stronger biofilm in the presence of minerals. The source of biofilms of thermo-resistant bacteria such as B. licheniformis is believed to be before the ultrafiltration zone represented by the 1% WPC with lactose and minerals where the whey protein concentration is about 0.6%.

  17. Calculation of conversion coefficients using Chinese adult reference phantoms for air submersion and ground contamination.

    PubMed

    Lu, Wei; Qiu, Rui; Wu, Zhen; Li, Chunyan; Yang, Bo; Liu, Huan; Ren, Li; Li, Junli

    2017-03-21

    The effective and organ equivalent dose coefficients have been widely used to provide assessment of doses received by adult members of the public and by workers exposed to environmental radiation from nuclear facilities under normal or accidental situations. Advancements in phantom types, weighting factors, decay data, etc, have led to the publication of newer results in this regard. This paper presents a new set of conversion coefficients for air submersion and ground contamination (with the use of Geant4) for photons from 15 keV to 10 MeV using the Chinese and International Commission on Radiological Protection (ICRP) adult reference male and female phantoms. The radiation fields, except for energy spectrum at low energies, were validated by the data obtained from the Monte Carlo code YURI. The effective dose coefficients of monoenergetic photons, obtained for the ICRP adult reference phantoms, agree well with recently published data for air submersion and ground contamination with a plane source at a depth of 0.5 g cm(-2) in soil, but an average difference of 36.5% is observed for ground surface contamination with the abovementioned radiation field. The average differences in organ equivalent dose coefficients between the Chinese and the ICRP adult reference phantoms are within 6% for most organs, but noticeable differences of up to 70% or even higher are found at photon energies below 30 keV under air submersion. The effective dose coefficients obtained with the Chinese adult reference phantoms are greater than those of the ICRP adult reference phantoms above 30 keV and 0.5 MeV for ground contamination and air submersion, respectively; the average differences from the Chinese adult reference phantoms are about 3.6% and 0.4% in the whole energy range with maximum differences of 31.8% and 27.6% at 15 keV for air submersion and ground contamination respectively. These differences are attributed to anatomical discrepancies in overlying tissue mass of an

  18. Calculation of conversion coefficients using Chinese adult reference phantoms for air submersion and ground contamination

    NASA Astrophysics Data System (ADS)

    Lu, Wei; Qiu, Rui; Wu, Zhen; Li, Chunyan; Yang, Bo; Liu, Huan; Ren, Li; Li, Junli

    2017-03-01

    The effective and organ equivalent dose coefficients have been widely used to provide assessment of doses received by adult members of the public and by workers exposed to environmental radiation from nuclear facilities under normal or accidental situations. Advancements in phantom types, weighting factors, decay data, etc, have led to the publication of newer results in this regard. This paper presents a new set of conversion coefficients for air submersion and ground contamination (with the use of Geant4) for photons from 15 keV to 10 MeV using the Chinese and International Commission on Radiological Protection (ICRP) adult reference male and female phantoms. The radiation fields, except for energy spectrum at low energies, were validated by the data obtained from the Monte Carlo code YURI. The effective dose coefficients of monoenergetic photons, obtained for the ICRP adult reference phantoms, agree well with recently published data for air submersion and ground contamination with a plane source at a depth of 0.5 g cm‑2 in soil, but an average difference of 36.5% is observed for ground surface contamination with the abovementioned radiation field. The average differences in organ equivalent dose coefficients between the Chinese and the ICRP adult reference phantoms are within 6% for most organs, but noticeable differences of up to 70% or even higher are found at photon energies below 30 keV under air submersion. The effective dose coefficients obtained with the Chinese adult reference phantoms are greater than those of the ICRP adult reference phantoms above 30 keV and 0.5 MeV for ground contamination and air submersion, respectively; the average differences from the Chinese adult reference phantoms are about 3.6% and 0.4% in the whole energy range with maximum differences of 31.8% and 27.6% at 15 keV for air submersion and ground contamination respectively. These differences are attributed to anatomical discrepancies in overlying tissue mass of an

  19. Air-sampling inlet contamination by aircraft emissions on the NASA CV-990 aircraft

    NASA Technical Reports Server (NTRS)

    Condon, E. P.; Vedder, J. F.

    1984-01-01

    Results of an experimental investigation of the contamination of air sampling inlets by aircraft emissions from the NASA CV-990 research aircraft are presented. This four-engine jet aircraft is a NASA facility used for many different atmospheric and meteorological experiments, as well as for developing spacecraft instrumentation for remote measurements. Our investigations were performed to provide information on which to base the selection of sampling locations for a series of multi-instrument missions for measuring tropospheric trace gases. The major source of contamination is the exhaust from the jet engines, which generate many of the same gases that are of interest in atmospheric chemistry, as well as other gases that may interfere with sampling measurements. The engine exhaust contains these gases in mixing ratios many orders of magnitude greater than those that occur in the clean atmosphere which the missions seek to quantify. Pressurized samples of air were collected simultaneously from a scoop located forward of the engines to represent clean air and from other multiport scoops at various aft positions on the aircraft. The air samples were analyzed in the laboratory by gas chromatography for carbon monoxide, an abundant combustion by-product. Data are presented for various scoop locations under various flight conditions.

  20. Application of Passive Sampling for Measuring Dissolved Concentrations of Organic Contaminants in the Water Column at Three U.S. EPA Marine Superfund Sites.

    EPA Science Inventory

    At contaminated sediment sites, including U.S. EPA Superfund sites, it is critical to measure water column concentrations of freely dissolved contaminants to understand the complete exposure of aquatic organisms to hydrophobic organic contaminants (HOCs). Historically, acquiring...

  1. Application of Passive Sampling for Measuring Dissolved Concentrations of Organic Contaminants in the Water Column at Three U.S. EPA Marine Superfund Sites

    EPA Science Inventory

    At contaminated sediment sites, including U.S. EPA Superfund sites, it is critical to measure water column concentrations of freely dissolved contaminants to understand the complete exposure of aquatic organisms to hydrophobic organic contaminants (HOCs). Historically acquiring ...

  2. Mobile ultra-clean unidirectional airflow screen reduces air contamination in a simulated setting for intra-vitreal injection.

    PubMed

    Lapid-Gortzak, Ruth; Traversari, Roberto; van der Linden, Jan Willem; Lesnik Oberstein, Sarit Y; Lapid, Oren; Schlingemann, Reinier O

    2017-02-01

    The aim of this study is to determine whether the use of a mobile ultra-clean laminar airflow screen reduces the air-borne particle counts in the setting of a simulated procedure of an intra-vitreal injection. A mobile ultra-clean unidirectional airflow (UDF) screen was tested in a simulated procedure for intra-vitreal injections in a treatment room without mechanical ventilation. One UDF was passed over the instrument tray and the surgical area. The concentration of particles was measured in the background, over the instrument table, and next to the ocular area. The degree of protection was calculated at the instrument table and at the surgical site. Use of the UDF mobile screen reduced the mean particle concentration (particles > 0.3 microns) on the instrument table by a factor of at least 100.000 (p < 0.05), and over the patient's eye by at least a factor of 436 (p < 0.05), which in clinical practice translates into significantly reduced air contamination. Mobile UDF screen reduces the mean particle concentration substantially. The mobile UDF screen may therefore allow for a safer procedural environment for ambulatory care procedures such as intra-vitreal injections in treatment rooms.

  3. Spatiotemporal characteristics of organic contaminant concentrations and ecological risk assessment in the Songhua River, China.

    PubMed

    Wang, Ce; Cyterski, Mike; Feng, Yujie; Gao, Peng; Sun, Qingfang

    2015-11-01

    To control source pollution and improve water quality, an understanding of the spatiotemporal characteristics of organic contaminant concentrations in affected receiving waters is necessary. The Songhua River in northeast China is the country's third-largest domestic river and loadings of organic contaminants along an industrialized section have made it the focal point of a national pollution reduction plan. In addition to water quality issues, management of the Songhua River basin must also address local economic development, aquatic ecosystem sustainability and political relationships with Russia. In three periods spanning 2006 to 2010, eight polycyclic aromatic hydrocarbons (PAHs) and eight phenols were measured in surface waters at ten monitoring sites along the river. A generalized linear model (GLM) was used to characterize water quality at different sites and time periods. Chemical concentrations of the organic compounds showed significant sinusoidal seasonal patterns and the concentrations declined significantly from 2006 to 2010, possibly due to management practices designed to control water pollution. A critical body residue analysis showed that water concentrations measured during the winter of 2007 across all monitoring sites, but especially at S1-Shaokou and S2-Songhuajiangcun, presented a high risk for fish species. The spatiotemporal characteristics of water quality and estimated ecological risks shown here add to the body of knowledge to develop policies on industrial output and pollution management strategies for the Songhua River basin.

  4. Quantifying the impact of runoff events on microbiological contaminant concentrations entering surface drinking source waters.

    PubMed

    Signor, R S; Roser, D J; Ashbolt, N J; Ball, J E

    2005-12-01

    Concentrations of microbiological contaminants in streams increase during rainfall-induced higher flow 'event' periods as compared to 'baseflow' conditions. If the stream feeds a drinking water reservoir, such periods of heightened pathogen loads may pose a challenge to the water treatment plant and subsequently a health concern to water consumers downstream. In order to manage this risk, it is desirable to first quantify the differences in surface water quality between baseflow and event conditions. The Event Mean Concentration (EMC) is a flow-weighted average concentration of a contaminant over the duration of a single event, proposed here as a standard parameter for quantifying the net effect of events on microbial water quality. Application of the EMC concept was assessed using flow and quality data for several events from an urbanised catchment. Expected mean EMCs were significantly larger than expected mean baseflow concentrations (p-value< or =0.012) for three microbial agents - Escherichia coil (13,000 [n = 7] v. 610 [n = 16] mpn/100 ml), Cryptosporidium (234 [n = 6] v. 51 [n = 16] oocysts/10 litres) and Campylobacter (48 [n = 5] v. 2.1 [n = 16] mpn/100ml). These parameter estimates were complemented by estimating data variability and uncertainty in the form of second-order random variables. As such the results are in a format appropriate for potential use as components in probabilistic risk assessments evaluating the effect runoff events have on drinking water quality.

  5. Changes in concentration of contaminants in Scott Creek, Western North Carolina

    NASA Astrophysics Data System (ADS)

    Allmendinger, N. E.; Clapp, R. B.

    2004-12-01

    Scott Creek is a 4th-order gravel-bedded stream in the Little Tennessee watershed in a mountainous region of Western North Carolina. The region is highly dependent on this river for water contact sports and input for a paper mill. Recently, water sample have shown high levels of fecal coliform in spite of efforts to fix a broken sewer pipeline and eliminate straight-piping. Our objective is to assess the current quality of the water, and to devise methods for future monitoring and prediction of contaminant concentration in the river. During a 5-day period in July 2004, we monitored the stage and velocity of the river as well as the concentration of nitrates, reactive phosphorous and fecal coliform in the water. Our results suggest that the nutrients and the bacteria counts vary in phase with the river discharge. Our analysis of the data leads us to conclude that both discharge and E. coli concentration are related to precipitation. The relationship between river stage and precipitation is complex, requiring a "multiple" regression equation which plots Q as a function of the previous 3 days of rainfall. The relationship between E. coli concentration and precipitation is much simpler, showing that the abundance of bacteria varies directly with daily rainfall. We infer from our data that it is unlikely that E. coli in Scott's Creek has a "point" source, suggesting that the bacterial contamination is related to undetected straight pipes and not to a steady sewer failure.

  6. Global Ammonia Concentrations Seen by the 13-years AIRS Measurements

    NASA Astrophysics Data System (ADS)

    Warner, Juying; Wei, Zigang; Larrabee Strow, L.; Dickerson, Russell; Nowak, John; Wang, Yuxuan

    2016-04-01

    Ammonia is an integral part of the nitrogen cycle and is projected to be the largest single contributor to each of acidification, eutrophication and secondary particulate matter in Europe by 2020 (Sutton et al., 2008). The impacts of NH3 also include: aerosol production affecting global radiative forcing, increases in emissions of the greenhouse gases nitrous oxide (N2O) and methane (CH4), and modification of the transport and deposition patterns of SO2 and NOx. Therefore, monitoring NH3 global distribution of sources is vitally important to human health with respect to both air and water quality and climate change. We have developed new daily and global ammonia (NH3) products from AIRS hyperspectral measurements. These products add value to AIRS's existing products that have made significant contributions to weather forecasts, climate studies, and air quality monitoring. With longer than 13 years of data records, these measurements have been used not only for daily monitoring purposes but also for inter-annual variability and short-term trend studies. We will discuss the global NH3 emission sources from biogenic and anthropogenic activities over many emission regions captured by AIRS. We will focus their variability in the last 13 years.

  7. Persistent environmental contaminants in human milk: concentrations and time trends in Italy.

    PubMed

    Abballe, Annalisa; Ballard, Terri J; Dellatte, Elena; di Domenico, Alessandro; Ferri, Fabiola; Fulgenzi, Anna Rita; Grisanti, Giulio; Iacovella, Nicola; Ingelido, Anna Maria; Malisch, Rainer; Miniero, Roberto; Porpora, Maria Grazia; Risica, Serena; Ziemacki, Gianni; De Felip, Elena

    2008-08-01

    Breast milk monitoring studies of persistent and toxic environmental contaminants are of primary importance for carrying out an adequate risk assessment at the actual levels of human exposure and represent a major source of information on infant perinatal exposure. Milk specimens from mothers of the general population of the Venice and Rome areas were collected over the 1998-2001 period, pooled, and analyzed for selected persistent organic pollutants such as polychlorodibenzodioxins (PCDDs), polychlorodibenzofurans (PCDFs), polychlorobiphenyls (PCBs), organochlorinated pesticides (p,p'-DDE, p,p'-DDT, hexachlorobenzene), and polybromodiphenyl ethers (PBDEs), and the heavy metals Cd, Co, Cu, Hg, Mn, Pb, Sn, and Zn. The goal was to verify whether mother milk from the Venice area, whose lagoon is partly under direct industrial impact, had a contaminant load greater than that from the Rome area, primarily urban. For mothers from the Venice area, the correlation between fish and fishery product consumption and contaminant concentrations in milk was also explored, with however inconclusive results. The concentrations of PCDDs, PCDFs, dioxin-like PCBs, and organochlorinated pesticides determined in this study were compared with those available from a previous analytical work carried out on 1987 human milk pools of domestic origin: the declining trend of the aforesaid contaminants in milk is confirmed to be in agreement with what was observed in other European countries. The breast milk content of (137)Cs and (40)K radionuclides was also determined and compared with data obtained in other research programmes carried out in Italy: the health risk for breastfed infants was deemed to be not significant.

  8. Time variations of 222Rn concentration and air exchange rates in a Hungarian cave.

    PubMed

    Nagy, Hedvig Éva; Szabó, Zsuzsanna; Jordán, Gyozo; Szabó, Csaba; Horváth, Akos; Kiss, Attila

    2012-09-01

    A long-term radon concentration monitoring was carried out in the Pál-völgy cave, Budapest, Hungary, for 1.5 years. Our major goal was to determine the time dependence of the radon concentration in the cave to characterise the air exchange and define the most important environmental parameters that influence the radon concentration inside the cave. The radon concentration in the cave air was measured continuously by an AlphaGuard radon monitor, and meteorological parameters outside the cave were collected simultaneously. The air's radon concentration in the cave varied between 104 and 7776 Bq m(-3), the annual average value was 1884±85 Bq m(-3). The summer to winter radon concentration ratio was as high as 21.8. The outside air temperature showed the strongest correlation with the radon concentration in the cave, the correlation coefficient (R) was 0.76.

  9. Critical oxygen concentration in hydrogenated amorphous silicon solar cells dependent on the contamination source

    SciTech Connect

    Woerdenweber, Jan; Merdzhanova, Tsvetelina; Gordijn, Aad; Stiebig, Helmut; Beyer, Wolfhard

    2010-03-08

    For hydrogenated amorphous silicon (a-Si:H) solar cells, the critical concentration of a given impurity defines the lowest concentration which causes a decay of solar cell efficiency. Values of 2-5x10{sup 19} cm{sup -3} are commonly found for the critical oxygen concentration (C{sub O}{sup crit}) of a-Si:H. Here we report a dependence of C{sub O}{sup crit} on the contamination source. For state-of-the-art a-Si:H solar cells prepared at the same plasma deposition conditions, we obtain with a (controllable) chamber wall leak C{sub O}{sup crit} approx2x10{sup 19} cm{sup -3} while for a leak in the gas supply line a higher C{sub O}{sup crit} of approx2x10{sup 20} cm{sup -3} is measured. No such dependence is observed for nitrogen.

  10. Guidelines for developing spacecraft maximum allowable concentrations for Space Station contaminants

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The National Aeronautics and Space Administration (NASA) is preparing to launch a manned space station by the year 1996. Because of concerns about the health, safety, and functioning abilities of the crews, NASA has requested that the National Research Council (NRC) through the Board on Environmental Studies and Toxicology (BEST) provide advice on toxicological matters for the space-station program. The Subcommittee on Guidelines for Developing Spacecraft Maximum Allowable Concentrations for Space Station Contaminants was established by the Committee on Toxicology (COT) to address NASA's concerns. Spacecraft maximum allowable concentrations (SMAC's) are defined as the maximum concentrations of airborne substances (such as gas, vapor, or aerosol) that will not cause adverse health effects, significant discomfort, or degradation in crew performance.

  11. “Modeling Trends in Air Pollutant Concentrations over the ...

    EPA Pesticide Factsheets

    Regional model calculations over annual cycles have pointed to the need for accurately representing impacts of long-range transport. Linking regional and global scale models have met with mixed success as biases in the global model can propagate and influence regional calculations and often confound interpretation of model results. Since transport is efficient in the free-troposphere and since simulations over Continental scales and annual cycles provide sufficient opportunity for “atmospheric turn-over”, i.e., exchange between the free-troposphere and the boundary-layer, a conceptual framework is needed wherein interactions between processes occurring at various spatial and temporal scales can be consistently examined. The coupled WRF-CMAQ model is expanded to hemispheric scales and model simulations over period spanning 1990-current are analyzed to examine changes in hemispheric air pollution resulting from changes in emissions over this period. The National Exposure Research Laboratory (NERL) Atmospheric Modeling and Analysis Division (AMAD) conducts research in support of EPA mission to protect human health and the environment. AMAD research program is engaged in developing and evaluating predictive atmospheric models on all spatial and temporal scales for forecasting the air quality and for assessing changes in air quality and air pollutant exposures, as affected by changes in ecosystem management and regulatory decisions. AMAD is responsible for pr

  12. Remediation of arsenic contaminated soil by coupling oxalate washing with subsequent ZVI/Air treatment.

    PubMed

    Cao, Menghua; Ye, Yuanyao; Chen, Jing; Lu, Xiaohua

    2016-02-01

    The application of a novel coupled process with oxalate washing and subsequent zero-valent iron (ZVI)/Air treatment for remediation of arsenic contaminated soil was investigated in the present study. Oxalate is biodegradable and widely present in the environment. With addition of 0.1 mol L(-1) oxalate under circumneutral condition, 83.7% and 52.6% of arsenic could be removed from a spiked kaolin and an actual contaminated soil respectively. Much more oxalate adsorption on the actual soil was attributed to the higher soil organic matter and clay content. Interestingly, oxalate retained in the washing effluent could act as an organic ligand to promote the oxidation efficiency of ZVI/Air at near neutral pH. Compared with the absence of oxalate, much more As(III) was oxidized. Arsenic was effectively adsorbed on iron (hydr)oxides as the consumption of oxalate and the increase of pH value. For the actual soil washing effluent, about 94.9% of total arsenic was removed after 120 min's treatment without pH adjustment. It has been demonstrated that As(V) was the dominant arsenic speciation adsorbed on iron (hydr)oxides. This study provides a promising alternative for remediation of arsenic contaminated soil in view of its low cost and environmental benign.

  13. Estimation of the dominant degrees of freedom for air pollutant concentration data: Applications to ozone measurements

    NASA Astrophysics Data System (ADS)

    Li, I.-Fen; Biswas, Pratim; Islam, Shafiqul

    A nonlinear dynamic analysis of air quality data has been performed and applied to a time series of ozone concentration data from the Cincinnati air shed. The analysis helped to identify the nature of the dynamics of the ozone concentrations and determine the number of degrees of freedom or dimensionality of the system. Results indicated that the dimensionality of the system was 3, indicating that there are three dominant variables affecting ozone concentration levels in the Cincinnati air shed. Statistical analysis was performed to infer that NO was correlated to ozone concentration levels.

  14. Measurement of sterigmatocystin concentrations in urine for monitoring the contamination of cattle feed.

    PubMed

    Fushimi, Yasuo; Takagi, Mitsuhiro; Uno, Seiichi; Kokushi, Emiko; Nakamura, Masayuki; Hasunuma, Hiroshi; Shinya, Urara; Deguchi, Eisaburo; Fink-Gremmels, Johanna

    2014-11-04

    This study aimed (1) at determining the levels of the fungal toxin sterigmatocystin (STC) in the feed and urine of cattle and (2) at evaluating the effects of supplementing the feed with a mycotoxin adsorbent (MA) on STC concentrations in urine. Two herds of female Japanese Black cattle were used in this study. The cattle in each herd were fed a standard ration containing rice straw from different sources and a standard concentrate; two groups of cattle from each herd (n = six per group) received the commercial MA, mixed with the concentrate or given as top-dressing, whereas a third group received no supplement and served as control. Urine and feed samples were collected at various time points throughout the experiment. STC concentrations were measured using liquid chromatography-tandem mass spectrometry (LC-TMS). STC concentrations in straw were higher in Herd 1 (range 0.15-0.24 mg/kg DM) than in Herd 2 (range <0.01-0.06 mg/kg DM). In Herd 1, STC concentrations in urine significantly declined 2 weeks after replacing the contaminated feed, whereas MA supplementation had no effect. In conclusion, mycotoxins in urine samples are useful biological markers for monitoring the systemic exposure of cattle to multiple mycotoxins, as well as evaluating the effectiveness of interventions.

  15. [Soil contamination with Toxocara sp. eggs in squares and public places from the city of La Plata. Buenos Aires, Argentina].

    PubMed

    Fonrouge, R; Guardis, M V; Radman, N E; Archelli, S M

    2000-01-01

    This study consisted of a stratified sampling, randomly taken, of the soil from the squares and parks of the city of La Plata, Province of Buenos Aires, in order to establish the prevalence of contamination caused by Toxocara sp. A total 242 soil samples was examined. From each sample a 10 grams aliquot was taken, washed in a 0.2% Tween 80 solution, and processed using the technique of concentration by flotation with sugar solution. There was a prevalence of 13.2%. In each positive sample, the quantity of eggs varied from 1 to 4. Toxocara sp. eggs were observed in 15 out of 22 squares and parks investigated. The sampling design and the processing method employed were satisfactory for the recovering and identification of Toxocara sp. eggs.

  16. The concentrations of culturable microorganisms in relation to particulate matter in urban air

    NASA Astrophysics Data System (ADS)

    Haas, D.; Galler, H.; Luxner, J.; Zarfel, G.; Buzina, W.; Friedl, H.; Marth, E.; Habib, J.; Reinthaler, F. F.

    2013-02-01

    The ambient air consists not only of gases but also of bioaerosols and particulate matter. The concentrations of particulate matter in relation to the culturable microorganisms in the urban ambient air and their dependence on air temperature and relative humidity were investigated. The seasonal distribution of particles sizes, the concentrations of aerobic mesophilic bacteria and xerophilic fungi in the air were evaluated. Moreover, the identification of the fungal genera Cladosporium, Aspergillus and Penicillium were conducted. Within one year at 177 days particle and microorganism concentrations in the ambient air were recorded in the city centre of Graz/Austria. The results show that the concentrations of fine particles and coarse particles were the highest in winter and decreased continuously to a minimum in the summer months depending on temperature and air humidity. The concentrations of xerophilic fungi showed no correlation to the different particle concentrations. The spore concentrations of Cladosporium spp. showed the same results of xerophilic fungi whereas the genera Penicillium and Aspergillus increased with the increase of fine particles. The concentrations of mesophilic bacteria were positively correlated with all particle counts. The maximum mesophilic bacteria concentrations were found in the winter months. Further studies are required to evaluate the concentrations of specific microorganisms in the natural environment in relation to the particulate matter.

  17. (Environmental investigation of ground water contamination at Wright-Patterson Air Force Base, Ohio)

    SciTech Connect

    Not Available

    1991-10-01

    In April 1990, Wright-Patterson Air Force Base (WPAFB) initiated an effort for the evaluation of potential removal of ground water contamination at the Base. This report presents a current assessment of the nature and extent of the contamination believed to be migrating across the southwestern boundary of Area C and the northern boundary of Area B based upon analysis of existing environmental data obtained from several sources. The existing data base indicates widespread, low-level contamination moving across Base boundaries at levels that pose no immediate threat to the Mad River Valley well fields. An investigation by the City of Dayton in May and June 1990, however, implies that a more identifiable plume of PCE and TCE may be crossing the southwestern boundary of Area C immediately downgradient of Landfill 5. More data is needed to delineate ground water contamination and to design and implement a suitable control system. This report concludes that although an extensive study of the boundaries in question would be the preferred approach, a limited, focused investigation and subsequent feasibility study can be accomplished with a reasonable certainty of achieving the desired outcome of this project.

  18. Tolerance of non-platinum group metals cathodes proton exchange membrane fuel cells to air contaminants

    NASA Astrophysics Data System (ADS)

    Reshetenko, Tatyana; Serov, Alexey; Artyushkova, Kateryna; Matanovic, Ivana; Sarah Stariha; Atanassov, Plamen

    2016-08-01

    The effects of major airborne contaminants (SO2, NO2 and CO) on the spatial performance of Fe/N/C cathode membrane electrode assemblies were studied using a segmented cell system. The injection of 2-10 ppm SO2 in air stream did not cause any performance decrease and redistribution of local currents due to the lack of stably adsorbed SO2 molecules on Fe-Nx sites, as confirmed by density functional theory (DFT) calculations. The introduction of 5-20 ppm of CO into the air stream also did not affect fuel cell performance. The exposure of Fe/N/C cathodes to 2 and 10 ppm NO2 resulted in performance losses of 30 and 70-75 mV, respectively. DFT results showed that the adsorption energies of NO2 and NO were greater than that of O2, which accounted for the observed voltage decrease and slight current redistribution. The cell performance partially recovered when the NO2 injection was stopped. The long-term operation of the fuel cells resulted in cell performance degradation. XPS analyses of Fe/N/C electrodes revealed that the performance decrease was due to catalyst degradation and ionomer oxidation. The latter was accelerated in the presence of air contaminants. The details of the spatial performance and electrochemical impedance spectroscopy results are presented and discussed.

  19. Hospital ventilation standards and energy conservation: chemical contamination of hospital air. Final report

    SciTech Connect

    Rainer, D.; Michaelsen, G.S.

    1980-03-01

    In an era of increasing energy conservation consciousness, a critical reassessment of the validity of hospital ventilation and thermal standards is made. If current standards are found to be excessively conservative, major energy conservation measures could be undertaken by rebalancing and/or modification of current HVAC systems. To establish whether or not reducing ventilation rates would increase airborne chemical contamination to unacceptable levels, a field survey was conducted to develop an inventory and dosage estimates of hospital generated airborne chemical contaminants to which patients, staff, and visitors are exposed. The results of the study are presented. Emphasis is on patient exposure, but an examination of occupational exposure was also made. An in-depth assessment of the laboratory air environment is documented. Housekeeping products used in survey hospitals, hazardous properties of housekeeping chemicals and probable product composition are discussed in the appendices.

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

    EPA Science Inventory

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

  1. A method for determination of methyl chloride concentration in air trapped in ice cores.

    PubMed

    Saito, Takuya; Yokouchi, Yoko; Aoki, Shuji; Nakazawa, Takakiyo; Fujii, Yoshiyuki; Watanabe, Okitsugu

    2006-05-01

    A method for measuring the concentration of methyl chloride (CH3Cl) in air trapped in an ice core was developed. The method combines the air extraction by milling the ice core samples under vacuum and the analysis of the extracted air with a cryogenic preconcentration/gas chromatograph/mass spectrometry system. The method was applied to air from Antarctic ice core samples estimated to have been formed in the pre-industrial and/or early industrial periods. The overall precision of the method deduced from duplicate ice core analyses was estimated to be better than +/-20 pptv. The measured CH3Cl concentration of 528+/-26 pptv was similar to the present-day concentration in the remote atmosphere as well as the CH3Cl concentration over the past 300 years obtained from Antarctic firn air and ice core analyses.

  2. EFFECT OF ACUTE STRESS ON PLASMA CONCENTRATIONS OF SEX AND STRESS HORMONES IN JUVENILE ALLIGATORS LIVING IN CONTROL AND CONTAMINATED LAKES

    EPA Science Inventory

    Environmental contaminants can act as stressors, inducing elevated circulating concentrations of stress hormones such as corticosterone and cortisol. Development in contaminated eggs has been reported to modify circulating sex steroid hormone concentrations in alligators (Alligat...

  3. Process for treating waste water having low concentrations of metallic contaminants

    DOEpatents

    Looney, Brian B; Millings, Margaret R; Nichols, Ralph L; Payne, William L

    2014-12-16

    A process for treating waste water having a low level of metallic contaminants by reducing the toxicity level of metallic contaminants to an acceptable level and subsequently discharging the treated waste water into the environment without removing the treated contaminants.

  4. Copper contamination effects on hydrogen-air combustion under SCRAMJET (supersonic combustion ramjet) testing conditions

    SciTech Connect

    Chang, S.L.; Lottes, S.A.; Berry, G.F.

    1990-01-01

    Two forms of copper catalytic reactions (homogeneous and heterogeneous) in hydrogen flames were found in a literature survey. Hydrogen atoms in flames recombine into hydrogen molecules through catalytic reactions, and these reactions which affect the timing of the combustion process. Simulations of hydrogen flames with copper contamination were conducted by using a modified general chemical kinetics program (GCKP). Results show that reaction times of hydrogen flames are shortened by copper catalytic reactions, but ignition times are relatively insensitive to the reactions. The reduction of reaction time depends on the copper concentration, copper phase, particle size (if copper is in the condensed phase), and initial temperature and pressure. The higher the copper concentration of the smaller the particle, the larger the reduction in reaction time. For a supersonic hydrogen flame (Mach number = 4.4) contaminated with 200 ppm of gaseous copper species, the calculated reaction times are reduced by about 9%. Similar reductions in reaction time are also computed for heterogeneous copper contamination. Under scramjet testing conditions, the change of combustion timing appears to be tolerable (less than 5%) if the Mach number is lower than 3 or the copper contamination is less than 100 ppm. The higher rate the Mach number, the longer the reaction time and the larger the copper catalytic effects. 7 tabs., 8 figs., 34 refs.

  5. AN INDOOR PESTICIDE AIR AND SURFACE CONCENTRATION MODEL

    EPA Science Inventory

    A thorough assessment of human exposure to environmental chemicals requires consideration of all processes in the sequence from source to dose. For assessment of exposure to pesticides following their use indoors, data and models are needed to estimate pesticide concentrations...

  6. 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.

  7. Measuring Concentrations of Particulate 140La in the Air

    SciTech Connect

    Okada, Colin E.; Kernan, Warnick; Keillor, Martin; Kirkham, Randy; Sorom, Rich D.; Van Etten, Don M.

    2016-01-01

    This article discusses deployment of air-samplers to measure the concentration of radioactive material in the air during the Full-Scale Radiological Dispersal Device experiments. Positioned 100-600 meters downwind of the release point, the filters were collected immediately and analyzed in a field laboratory. The article discusses quantities for total activity collected on the air filters as well as additional information to compute the average or integrated air concentrations. In the case of a public emergency, this type of information would be important for decision makers and responders.

  8. Assessment of natural attenuation of ground-water contamination at sites FT03, LF13, and WP14/LF15, Dover Air Force Base, Delaware

    USGS Publications Warehouse

    Barbaro, Jeffrey R.

    2002-01-01

    Water-quality, aquifer-sediment, and hydro-logic data were used to assess the effectiveness of natural attenuation of ground-water contamination at Fire Training Area Three, the Rubble Area Landfill, the Liquid Waste Disposal Landfill, and the Receiver Station Landfill in the East Management Unit of Dover Air Force Base, Delaware. These sites, which are contaminated with chlorinated solvents and fuel hydrocarbons, are under-going long-term monitoring to determine if natural attenuation continues to sufficiently reduce contaminant concentrations to meet regulatory requirements. This report is the first assessment of the effectiveness of natural attenuation at these sites since long-term monitoring began in 1999, and follows a preliminary investigation done in 1995?96. This assessment was done by the U.S. Geological Survey in cooperation with the U.S. Air Force.Since 1995?96, additional information has been collected and used in the current assessment. The conclusions in this report are based primarily on ground-water samples collected from January through March 2000. Previous analytical results from selected wells, available geologic and geo-physical well logs, and newly acquired information such as sediment organic-carbon measurements, hydraulic-conductivity measurements determined from slug tests on wells in the natural attenuation study area, and water-level measurements from surficial-aquifer wells also were used in this assessment. This information was used to: (1) calculate retardation factors and estimate contaminant migration velocities, (2) improve estimates of ground-water flow directions and inferred contaminant migration pathways, (3) better define the areal extent of contamination and the proximity of contaminants to discharge areas and the Base boundary, (4) develop a better under-standing of the vertical variability of contaminant concentrations and redox conditions, (5) evaluate the effects of temporal changes on concentrations in the plumes and

  9. Contaminants of emerging concern in reverse osmosis brine concentrate from indirect/direct water reuse applications.

    PubMed

    Romeyn, Travis R; Harijanto, Wesley; Sandoval, Sofia; Delagah, Saied; Sharbatmaleki, Mohamadali

    2016-01-01

    Water shortage is becoming more common due to droughts and global population increases resulting in the increasing popularity of water reuse to create new water sources. Reverse osmosis (RO) membrane systems are popular in these applications since they can produce drinking water quality effluent. Unfortunately, RO systems have the drawback of generating concentrate streams that contain contaminants rejected by the membrane including chemicals of emerging concern (CECs). CECs are chemicals such as hormones, steroids, pesticides, pharmaceuticals, and personal care products that are used for their intended purpose and then released into wastewater. CECs are believed to be detrimental to aquatic wildlife health and pose an unknown human health risk. This research gathered the existing knowledge on CEC presence in concentrate, available proven concentrate treatment methods, their CEC removal abilities, and current CEC regulations. It was found that 127 CECs have been measured in RO concentrate with 100 being detected at least once. The most potent treatment process available is UV/H2O2 as it offers the highest removal rates for the widest range of chemicals. The less expensive process of ozone/biologically activated carbon offers slightly lower removal abilities. This comprehensive report will provide the groundwork for better understanding, regulating and treating concentrate stream CECs.

  10. The relationship between unconfined compressive strength and leachate concentration of stabilised contaminated sediment

    NASA Astrophysics Data System (ADS)

    Kabir Aliyu, Mohammed; Tarmizi Abd Karim, Ahmad; -Ming Chan, Chee

    2016-11-01

    Solidification/Stabilization (S/S) treatment was used in this study to immobilise copper (Cu) in contaminated river sediment. The sediment was artificially contaminated by spiking the solution of Copper sulphate (CuSO4.5H2O) to so as to get an average of 1000 ppm target concentration. Portland composite cement and Rice husk ash (RHA) were used as S/S agents. The amount of cement added to the mixture was l0% and while rice husk ash at the rate of 5%, l0%, 15% and 20% to the total dry weight of the mixture and then was cured for 7, 14 and 28 days. The unconfined compressive strength test (UCS) and toxicity characteristic leaching procedure (TCLP) were used to evaluate the effectiveness of the S/S treatments. From the results obtained it indicates that the partial replacement of cement with RHA in the binder system has increased the strength and the leachate concentration of copper was less in the treated sediment samples if compared with the untreated ones.

  11. Model for Correlating Real-Time Survey Results to Contaminant Concentrations - 12183

    SciTech Connect

    Walker, Stuart A.

    2012-07-01

    The U.S. Environmental Protection Agency (EPA) Superfund program is developing a new Counts Per Minute (CPM) calculator to correlate real-time survey results, which are often expressed as counts per minute, to contaminant concentrations that are more typically provided in risk assessments or for cleanup levels, usually expressed in pCi/g or pCi/m{sup 2}. Currently there is no EPA guidance for Superfund sites on correlating count per minute field survey readings back to risk, dose, or other ARAR based concentrations. The CPM calculator is a web-based model that estimates a gamma detector response for a given level of contamination. The intent of the CPM calculator is to facilitate more real-time measurements within a Superfund response framework. The draft of the CPM calculator is still undergoing internal EPA review. This will be followed by external peer review. It is expected that the CPM calculator will at least be in peer review by the time of WM2012 and possibly finalized at that time. The CPM calculator should facilitate greater use of real-time measurement at Superfund sites. The CPM calculator may also standardize the process of converting lab data to real time measurements. It will thus lessen the amount of lab sampling that is needed for site characterization and confirmation surveys, but it will not remove the need for sampling. (authors)

  12. Electrical conductivity of aqueous salt-free concentrated suspensions. Effects of water dissociation and CO2 contamination.

    PubMed

    Carrique, Félix; Ruiz-Reina, Emilio

    2009-07-30

    In this paper we explore the effects of water dissociation and CO2 contamination on the electrical conductivity of salt-free concentrated suspensions in static electric fields. The conductivity model here presented is based on a new description of the equilibrium double layer for particles in "realistic" salt-free suspensions recently developed by the authors to account for the latter effects (Ruiz-Reina, E.; Carrique, F. J. Phys. Chem. B 2008, 112, 11960). It was shown that in most of the cases the neglecting of those effects would lead to a very poor description of common salt-free suspensions, especially, but not only, if the suspensions have been in contact with air. As shown in this paper, the presence of only water dissociation ions suffices to provoke very important changes in the standard salt-free predictions. A realistic aqueous salt-free suspension consists of an aqueous suspension without any electrolyte added during the preparation but including the following ionic species: (i) the "added counterions" stemming from the particle charging process that counterbalance their surface charge (with just this ionic species, the suspension can be considered as an ideal or pure salt-free one), (ii) the H+ and OH- ions from water dissociation, and (iii) the ions produced by the atmospheric CO2 contamination. The model is based on the classical Poisson-Boltzmann theory, the appropriate local chemical reactions, the standard electrokinetic equations, and the cell model approximation to account for electro-hydrodynamic particle-particle interactions. Thus, we have studied the electrical conductivity of such realistic salt-free suspensions for different particle volume fraction phi and surface charge density sigma, and compared it with results of pure salt-free conductivity predictions. The numerical results have shown that water dissociation ions and/or CO2 contamination has an extreme influence on the suspension conductivity values at low-moderate particle volume

  13. Contaminant concentrations in Asian carps, invasive species in the Mississippi and Illinois Rivers.

    PubMed

    Rogowski, D L; Soucek, D J; Levengood, J M; Johnson, S R; Chick, J H; Dettmers, J M; Pegg, M A; Epifanio, J M

    2009-10-01

    Populations of invasive fishes quickly reach extremely high biomass. Before control methods can be applied, however, an understanding of the contaminant loads of these invaders carry is needed. We investigated differences in concentrations of selected elements in two invasive carp species as a function of sampling site, fish species, length and trophic differences using stable isotopes (delta (15)N, delta (13)C). Fish were collected from three different sites, the Illinois River near Havana, Illinois, and two sites in the Mississippi River, upstream and downstream of the Illinois River confluence. Five bighead carp (Hypophthalmichthys nobilis) and five silver carp (Hypophthalmichthys molitrix) from each site were collected for muscle tissue analyses. Freshwater mussels (Amblema plicata) previously collected in the same areas were used as an isotopic baseline to standardize fish results among sites. Total fish length, trophic position, and corrected (13)C, were significantly related to concentrations of metals in muscle. Fish length explained the most variation in metal concentrations, with most of that variation related to mercury levels. This result was not unexpected because larger fish are older, giving them a higher probability of exposure and accumulation of contaminants. There was a significant difference in stable isotope profiles between the two species. Bighead carp occupied a higher trophic position and had higher levels of corrected (13)C than silver carp. Additionally bighead carp had significantly lower concentrations of arsenic and selenium than silver carp. Stable isotope ratios of nitrogen in Asian carp were at levels that are more commonly associated with higher-level predators, or from organisms in areas containing high loads of wastewater effluent.

  14. [Role of environment in complex diseases: air pollution and food contaminants].

    PubMed

    Scheen, A J; Giet, D

    2012-01-01

    Our polluted environment exposes human beings, along their life, to various toxic compounds that could trigger and aggravate different complex diseases. Such a phenomenon is well recognized for cardiovascular diseases, respiratory diseases and cancers, but other chronic inflammatory disorders may also been implicated. The most common factors, but also the most toxic, and thereby the most extensively investigated, are air pollutants (both indoor and outdoor pollution) and various contaminants present in drinking water and food (organic compounds, chemical products, heavy metals, ...). The complex interrelationships between food and pollutants, on the one hand, and between gene and environmental pollutants, including the influence of epigenetics, on the other hand, deserve further careful studies.

  15. Influence of root-exudates concentration on pyrene degradation and soil microbial characteristics in pyrene contaminated soil.

    PubMed

    Xie, Xiao-mei; Liao, Min; Yang, Jing; Chai, Juan-juan; Fang, Shu; Wang, Run-han

    2012-08-01

    The effect of ryegrass (Lolium perenne L.) root-exudates concentration on pyrene degradation and the microbial ecological characteristics in the pyrene contaminated soil was investigated by simulating a gradually reducing concentration of root exudates with the distance away from root surface in the rhizosphere. Results showed that, after the root-exudates were added 15 d, the pyrene residue in contaminated soil responded nonlinearly in the soils with the same pyrene contaminated level as the added root-exudates concentration increased, which decreased first and increased latter with the increase of the added root-exudates concentration. The lowest pyrene concentration appeared when the root exudates concentration of 32.75 mg kg(-1) total organic carbon (TOC) was added. At the same time, changes of microbial biomass carbon (MBC, C(mic)) and microbial quotient (C(mic)/C(org)) were opposite to the trend of pyrene degradation as the added root-exudates concentration increased. Phospholipid fatty acid (PLFA) analysis revealed that bacteria was the dominating microbial community in pyrene contaminated soil, and the changing trends of pyrene degradation and bacteria number were the same. The changing trend of endoenzyme-dehydrogenase activity was in accordance with that of soil microbe, indicating which could reflect the quantitative characteristic of detoxification to pyrene by soil microbe. The changes in the soils microbial community and corresponding microbial biochemistry characteristics were the ecological mechanism influencing pyrene degradation with increasing concentration of the added root-exudates in the pyrene contaminated soil.

  16. Daily and seasonal variations in radon activity concentration in the soil air.

    PubMed

    Műllerová, Monika; Holý, Karol; Bulko, Martin

    2014-07-01

    Radon activity concentration in the soil air in the area of Faculty of Mathematics, Physics and Informatics (FMPI) in Bratislava, Slovak Republic, has been continuously monitored since 1994. Long-term measurements at a depth of 0.8 m and short-term measurements at a depth of 0.4 m show a high variability in radon activity concentrations in the soil. The analysis of the data confirms that regular daily changes in radon activity concentration in the soil air depend on the daily changes in atmospheric pressure. It was also found that the typical annual courses of the radon activity concentration in the soil air (with summer minima and winter maxima) were disturbed by mild winter and heavy summer precipitation. Influence of precipitation on the increase in the radon activity concentration in the soil air was observed at a depth of 0.4 m and subsequently at a depth of 0.8 m.

  17. Outbreak of invasive Aspergillus infection in surgical patients, associated with a contaminated air-handling system.

    PubMed

    Lutz, Brock D; Jin, Jiankang; Rinaldi, Michael G; Wickes, Brian L; Huycke, Mark M

    2003-09-15

    An outbreak of Aspergillus infection at a tertiary care hospital was identified among inpatients who had amputation wounds, peritonitis, allograft nephritis, or mediastinitis. During a 2-year period, 6 patients were identified, all of whom had Aspergillus species recovered from samples from normally sterile sites. All cases clustered in the operating theater during a single 12-day period. To assess operating theater air quality, particle counts were measured as surrogate markers for Aspergillus conidia. A substantial increase in the proportion of airborne particles > or =3 microm in size (range, 3-fold to 1000-fold) was observed in many operating rooms. A confined space video camera identified moisture and contamination of insulating material in ductwork and variable airflow volume units downstream of final filters. No additional invasive Aspergillus wound infections were identified after the operating theater air-handling systems were remediated, suggesting that this unusual outbreak was due to the deterioration of insulating material in variable airflow volume units.

  18. A laboratory assessment of air sparging performance on oil-contaminated soil

    SciTech Connect

    Harkness, M.R.; Bracco, A.A.; Ciampa, J.D.

    1995-12-31

    The efficacy of air sparging to remediate a subsurface plume of transformer oil is evaluated in a comprehensive laboratory study. Shake flask assays containing contaminated soil indicated the oil was highly (>80%) biodegradable by indigenous bacteria when oxygen, nitrogen, and phosphorous were supplied. From 50 to 60% of the oil was removed from the soil in a 169-day biodegradation rate study performed in laboratory soil columns designed to mimic air sparged conditions. Maximal total petroleum hydrocarbon (TPH) biodegradation rates of {approximately}70 mg/kg per day were observed in nutrient (N and P) amended columns at 23 C, based upon O{sub 2} uptake and CO{sub 2} production. The total TPH biodegraded in these columns was 3-fold higher than in an unamended control column.

  19. Enhancing Potentially Plant-Available Lead Concentrations in Contaminated Residential Soils Using a Biodegradable Chelating Agent

    NASA Astrophysics Data System (ADS)

    Andra, S.; Datta, R.; Sarkar, D.; Saminathan, S.

    2007-12-01

    Chelation of heavy metals is an important factor in enhancing metal solubility and, hence, metal availability to plants to promote phytoremediation. In the present study, we compared the effects of application of a biodegradable chelating agent, namely, ethylenediaminedisuccinic acid (EDDS) on enhancing plant available form of lead (Pb) in Pb-based paint contaminated residential soils compared to that of a more commonly used, but non-biodegradable chelate, i.e., ethylenediaminetetraacetic acid (EDTA). Development of a successful phytoremediation model for metals such as Pb depends on a thorough understanding of the physical and chemical properties of the soil, along with the optimization of a chelate treatment to mobilize Pb from `unavailable' pools to potentially plant available fraction. In this context, we set out to perform batch incubation experiments to investigate the effectiveness of the two aforementioned chelates in enhancing plant available Pb at four different concentrations (0, 5, 10 and 15 mM/kg soil) and three treatment durations (0, 10 and 30 days). We selected 12 contaminated residential soils from two major metropolitan areas (San Antonio, TX and Baltimore, MD) with varying soil physico-chemical properties - the soils from San Antonio were primarily alkaline and those from Baltimore were typically acidic. Total soil Pb concentrations ranged between 256 mg/kg and 4,182 mg/kg. Our results show that both chelates increased the solubility of Pb, otherwise occluded in the complex soil matrix. For both EDTA and EDDS, the exchangeable concentrations of soil Pb also increased with increase in chelate concentration and incubation time. The most effective treatment was 15 mM chelate kg-1 soil incubated for 30 days, which caused many fold increase in potentially plant available Pb (a combination of the soluble and exchangeable fractions) relative to the unamended controls. Step wise multiple linear regression analysis using chelate-extractable Pb and soil

  20. Biofiltration of benzene contaminated air streams using compost-activated carbon filter media

    SciTech Connect

    Zhu, L.; Kocher, W.M.; Abumaizar, R.J.

    1998-12-31

    Three laboratory-scale biofilter columns were operated for 81 days to investigate the removal of benzene from a waste gas stream. The columns contain a mixture of yard waste and sludge compost as biomedia. Different amounts of granular activated carbon (GAC) are mixed with the compost in two of the three columns to evaluate the extent to which biofilter performance can be enhanced. The effects of different operating conditions on the performance of the removal of benzene from air were evaluated. More than 90% removal efficiency was observed for an influent benzene concentration of about 75 ppm and an air flow rate of 0.3 L/min. in all 3 columns under steady-state conditions. Under most cases of shock loading conditions, such as a sudden increase in the air flow rate, or the benzene concentration in the influent, the biofilters containing GAC provided higher removal efficiencies and more stable operation than the biofilter containing compost only.

  1. SERDP and ESTCP Workshop on Vapor Intrusion into Indoor Air from Contaminated Groundwater

    DTIC Science & Technology

    2014-03-01

    mitigating radon and volatile organic compound (VOC) subsurface vapor intrusion. These projects have determined that vapor concentrations can be highly...Validation of More Cost-Effective Methods for Mitigating Radon and VOC Subsurface Vapor Intrusion to Indoor Air Todd McAlary Geosyntec 1045 Morning

  2. 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.

  3. Effect of tidal fluctuations on transient dispersion of simulated contaminant concentrations in coastal aquifers

    USGS Publications Warehouse

    La Licata, Ivana; Langevin, Christian D.; Dausman, Alyssa M.; Alberti, Luca

    2013-01-01

    Variable-density groundwater models require extensive computational resources, particularly for simulations representing short-term hydrologic variability such as tidal fluctuations. Saltwater-intrusion models usually neglect tidal fluctuations and this may introduce errors in simulated concentrations. The effects of tides on simulated concentrations in a coastal aquifer were assessed. Three analyses are reported: in the first, simulations with and without tides were compared for three different dispersivity values. Tides do not significantly affect the transfer of a hypothetical contaminant into the ocean; however, the concentration difference between tidal and non-tidal simulations could be as much as 15%. In the second analysis, the dispersivity value for the model without tides was increased in a zone near the ocean boundary. By slightly increasing dispersivity in this zone, the maximum concentration difference between the simulations with and without tides was reduced to as low as 7%. In the last analysis, an apparent dispersivity value was calculated for each model cell using the simulated velocity variations from the model with tides. Use of apparent dispersivity values in models with a constant ocean boundary seems to provide a reasonable approach for approximating tidal effects in simulations where explicit representation of tidal fluctuations is not feasible.

  4. Effect of tidal fluctuations on transient dispersion of simulated contaminant concentrations in coastal aquifers

    USGS Publications Warehouse

    La Licata, Ivana; Langevin, Christian D.; Dausman, Alyssa M.; Alberti, Luca

    2011-01-01

    Variable-density groundwater models require extensive computational resources, particularly for simulations representing short-term hydrologic variability such as tidal fluctuations. Saltwater-intrusion models usually neglect tidal fluctuations and this may introduce errors in simulated concentrations. The effects of tides on simulated concentrations in a coastal aquifer were assessed. Three analyses are reported: in the first, simulations with and without tides were compared for three different dispersivity values. Tides do not significantly affect the transfer of a hypothetical contaminant into the ocean; however, the concentration difference between tidal and non-tidal simulations could be as much as 15%. In the second analysis, the dispersivity value for the model without tides was increased in a zone near the ocean boundary. By slightly increasing dispersivity in this zone, the maximum concentration difference between the simulations with and without tides was reduced to as low as 7%. In the last analysis, an apparent dispersivity value was calculated for each model cell using the simulated velocity variations from the model with tides. Use of apparent dispersivity values in models with a constant ocean boundary seems to provide a reasonable approach for approximating tidal effects in simulations where explicit representation of tidal fluctuations is not feasible.

  5. [Environmental investigation of ground water contamination at Wright-Patterson Air Force Base, Ohio]. Volume 5, Field Investigation report

    SciTech Connect

    Not Available

    1992-03-01

    An environmental investigation of ground water conditions has been undertaken at Wright-Patterson Air Force Base (WPAFB), Ohio to obtain data to assist in the evaluation of a potential removal action to prevent, to the extent practicable, migration of the contaminated ground water across Base boundaries. Field investigations were limited to the central section of the southwestern boundary of Area C and the Springfield Pike boundary of Area B. Further, the study was limited to a maximum depth of 150 feet below grade. Three primary activities of the field investigation were: (1) installation of 22 monitoring wells, (2) collection and analysis of ground water from 71 locations, (3) measurement of ground water elevations at 69 locations. Volatile organic compounds including trichloroethylene, perchloroethylene, and/or vinyl chloride were detected in concentrations exceeding Maximum Contaminant Levels (MCL) at three locations within the Area C investigation area. Ground water at the Springfield Pike boundary of Area B occurs in two primary units, separated by a thicker-than-expected clay layers. One well within Area B was determined to exceed the MCL for trichloroethylene.

  6. (Environmental investigation of ground water contamination at Wright-Patterson Air Force Base, Ohio)

    SciTech Connect

    Thompson, Bill

    1991-10-01

    In April 1990, Wright-Patterson Air Force Base (WPAFB), initiated an investigation to evaluate a potential Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) removal action to prevent, to the extent practicable, the offsite migration of contaminated ground water from WPAFB. WPAFB retained the services of the Environmental Management Operations (EMO) and its principle subcontractor, International Technology Corporation (IT) to complete Phase 1 of the environmental investigation of ground-water contamination at WPAFB. Phase 1 of the investigation involves the short-term evaluation and potential design for a program to remove ground-water contamination that appears to be migrating across the western boundary of Area C, and across the northern boundary of Area B along Springfield Pike. Primarily, Task 4 of Phase 1 focuses on collection of information at the Area C and Springfield Pike boundaries of WPAFB. This Sampling and Analysis Plan (SAP) has been prepared to assist in completion of the Task 4 field investigation and is comprised of the Quality Assurance Project Plan (QAPP) and the Field Sampling Plan (FSP).

  7. Time Evolution of Activity Concentration of Natural Emitters in a Scenario Affected By Previous Phosphogypsum Contamination

    NASA Astrophysics Data System (ADS)

    Villa, M.; Mantero, J.; Mosqueda, F.; Hurtado, S.; Manjón, G.; Vaca, F.; García-Tenorio, R.

    2008-08-01

    The estuary formed by the confluence of Tinto and Odiel river-mouths is located in the South of Spain, close to Huelva town. This estuary has been deeply studied through the years because it has a double particularity. On one hand, since the beginning of the 1960s, the estuary has been affected by direct and indirect phosphogypsum (pg.) releases from two phosphoric acid and fertilizers factories that are working in the area. On the other hand, the pyrite mining operations upstream the Odiel and Tinto rivers has caused historically the formation of H2SO4, through oxidation of the natural sulphur deposits, the acidification of the waters and the consequent mobilisation of heavy metals from the mining area to the Huelva estuary. As a consequence, enhancement contamination levels in natural emitters from the 238U series were found in the surroundings of the factories in the previous years to 1998. However, in 1998 the management policy of waste releases drastically changed in the area, and direct discharges to Tinto and Odiel River had to be ceased. A thorough study of the affected zone is being carried out. Riverbed sediments and water samples have been analyzed from four different sampling campaigns in the estuary during the years 1999, 2001, 2002 and 2005. Different radioanalytical techniques have been employed to obtain the activity concentrations of U-isotopes, Th-isotopes, 226Ra, 210Pb and 210Po. Furthermore, the results for the rates of de-contamination of the area are presented. This data will be discussed in order to establish the present status of the contamination in the area, and moreover, to predict the time-evolution of the self-cleaning

  8. In-situ remediation of soil contaminated with low concentrations of radionuclides

    SciTech Connect

    Entry, J.A.; Vance, N.C.; Hamilton, M.A.; Zabowski, D.

    1994-12-31

    Since plants are known to take up and accumulate {sup 37}Cs and {sup 90}Sr, removal of these radionuclides from contaminated soils by plants would provide a reliable and economical method of remediation. One approach is to use fast-growing, perennial plants combined with specific mycorrhizal fungi to maximize plant accumulation and removal of {sup 137}Cs and {sup 90}Sr from contaminated soils. The objective is to find a series of plants that can quickly accumulate and remove radionuclides from soils. Specific mycorrhizal fungi inoculated onto plants should enhance the uptake of {sup 137}Cs and {sup 90}Sr. Laboratory studies indicate that certain plants may be able to remove radionuclides, especially {sup 137}Cs and {sup 90}Sr, from soil over a period of less than 10 yr. In addition, one could change the physical and chemical properties of the soil to enhance the availability of {sup 137}Cs and {sup 90}Sr to plants while decreasing the mobility of these radionuclides in soil. The above-ground portion of perennial plants would be harvested. High-temperature combustion would be used to oxidize plant material, concentrating {sup 137}Cs and {sup 90}Sr in ash for disposal. One of the many strengths of this method is its applicability to any terrestrial environment. Transportation of radionuclides from the site could be minimized through plant management, selection of plants that are less palatable to grazing animals, and fencing. Environmental conditions will change with each site; however, radionuclide accumulation could be accomplished by plants that are adapted to a wide spectrum of environmental conditions. There is no other practical and economic method to remove these radionuclides form the vast areas of land that have been contaminated by nuclear testing and nuclear reactor accidents.

  9. Time Evolution of Activity Concentration of Natural Emitters in a Scenario Affected By Previous Phosphogypsum Contamination

    SciTech Connect

    Villa, M.; Hurtado, S.; Mantero, J.; Manjon, G.; Garcia-Tenorio, R.; Mosqueda, F.; Vaca, F.

    2008-08-07

    The estuary formed by the confluence of Tinto and Odiel river-mouths is located in the South of Spain, close to Huelva town. This estuary has been deeply studied through the years because it has a double particularity. On one hand, since the beginning of the 1960s, the estuary has been affected by direct and indirect phosphogypsum (pg.) releases from two phosphoric acid and fertilizers factories that are working in the area. On the other hand, the pyrite mining operations upstream the Odiel and Tinto rivers has caused historically the formation of H{sub 2}SO{sub 4}, through oxidation of the natural sulphur deposits, the acidification of the waters and the consequent mobilisation of heavy metals from the mining area to the Huelva estuary. As a consequence, enhancement contamination levels in natural emitters from the {sup 238}U series were found in the surroundings of the factories in the previous years to 1998. However, in 1998 the management policy of waste releases drastically changed in the area, and direct discharges to Tinto and Odiel River had to be ceased.A thorough study of the affected zone is being carried out. Riverbed sediments and water samples have been analyzed from four different sampling campaigns in the estuary during the years 1999, 2001, 2002 and 2005. Different radioanalytical techniques have been employed to obtain the activity concentrations of U-isotopes, Th-isotopes, {sup 226}Ra, {sup 210}Pb and {sup 210}Po. Furthermore, the results for the rates of de-contamination of the area are presented. This data will be discussed in order to establish the present status of the contamination in the area, and moreover, to predict the time-evolution of the self-cleaning.

  10. Extreme air pollution with contaminants originating from the mining-metallurgical processes.

    PubMed

    Serbula, Snezana M; Milosavljevic, Jelena S; Radojevic, Ana A; Kalinovic, Jelena V; Kalinovic, Tanja S

    2017-05-15

    Levels of SO2 and metals/metalloids in the air near a copper smelter in Bor (Serbia) from 2009 to 2015 were presented in this study. Annual levels of SO2 were constantly above the proposed limit value (LV), at almost all the measuring sites. SO2 concentrations on an annual level measured in different zones in Bor were several times higher compared to the LV in 2011, 2012, 2014 and 2015. Enormously high daily SO2 concentrations measured at the suburban zone (3734μgm(-3)) was 187 times higher than the LV given by the World Health Organization. Annual arsenic concentrations exceeded the LV at all the measuring sites during the study period. Extremely high annual As level in 2012 was 21 times higher than the LV proposed by the European Union. The annual lead and cadmium concentrations frequently exceeded the LV. The vicinity of the measuring sites to the copper smelter and the location of the sites in regard to the prevailing wind directions contribute to higher content of air pollutants. The data presented in this study revealed that extremely high concentrations of air polluting substances could rank the town of Bor as one of the most polluted regions in Serbia and beyond.

  11. EFFECTS OF METAL COMPONENTS IN CONCENTRATED AMBIENT AIR PARTICLES ON PULMONARY INJURY

    EPA Science Inventory

    EFFECTS OF METAL COMPONENTS IN CONCENTRATED AMBIENT AIR PARTICLES ON PULMONARY INJURY. Yuh-Chin Huang, Jackie Stonehuerner, Jackie Carter, Andrew J. Ghio, Robert B. Devlin. NHEERL, US EPA, RTP, NC.
    The mechanisms for cardiopulmonary morbidity associated with exposure to air po...

  12. 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 ...

  13. AGE AND STRAIN INFLUENCES ON LUNG RESPONSES TO CONCENTRATED AIR PARTICULATES (CAPS) IN RODENTS

    EPA Science Inventory

    Asthma, an inflammatory airways disease, is an urgent health problem. Recent epidemiologic studies have demonstrated positive associations between ambient air particulate matter concentrations and daily respiratory morbidity ? including exacerbations of asthma. Of note, elderly i...

  14. Effect of soil biochar concentration on the mitigation of emerging organic contaminant uptake in lettuce.

    PubMed

    Hurtado, Carlos; Cañameras, Núria; Domínguez, Carmen; Price, Gordon W; Comas, Jordi; Bayona, Josep M

    2017-02-05

    Although crop uptake of emerging organic contaminants (EOC) from irrigation water and soils has been previously reported, successful mitigation strategies have not yet been established. In this study, soil was amended with a wood-based biochar (BC) at two rates (0, 2.5 and 5% w/w) to evaluate the effect on mitigation of EOC uptake (i.e. bisphenol A, caffeine, carbamazepine, clofibric acid, furosemide, ibuprofen, methyl dihydrojasmonate, tris(2-chloroethyl)phosphate, triclosan, and tonalide) in lettuce (Lactuca sativa L.). After 28 days of irrigation with water containing EOCs at 15μgL(-1), the average EOC concentration in roots and leaves decreased by 20-76% in biochar amended soil relative to non BC-amended soil. In addition, the enantiomeric fractions (EF) of ibuprofen (IBU) in biochar amended soils (EF=0.58) and unamended soils (EF=0.76) suggest that the IBU sorbed fraction in BC is more recalcitrant to its biodegradation.

  15. Contact angles at the water-air interface of hydrocarbon-contaminated soils and clay minerals

    NASA Astrophysics Data System (ADS)

    Sofinskaya, O. A.; Kosterin, A. V.; Kosterina, E. A.

    2016-12-01

    Contact angles at the water-air interface have been measured for triturated preparations of clays and soils in order to assess changes in their hydrophobic properties under the effect of oil hydrocarbons. Tasks have been to determine the dynamics of contact angle under soil wetting conditions and to reveal the effect of chemical removal of organic matter from soils on the hydrophilicity of preparations. The potentialities of static and dynamic drop tests for assessing the hydrophilic-hydrophobic properties of soils have been estimated. Clays (kaolinite, gumbrine, and argillite) have been investigated, as well as plow horizons of soils from the Republic of Tatarstan: heavy loamy leached chernozem, medium loamy dark gray forest soil, and light loamy soddy-calcareous soil. The soils have been contaminated with raw oil and kerosene at rates of 0.1-3 wt %. In the uncontaminated and contaminated chernozem, capillary water capacity has been maintained for 250 days. The contact angles have been found to depend on the degree of dispersion of powdered preparation, the main type of clay minerals in the soil, the presence and amount of oxidation-resistant soil organic matter, and the soil-water contact time. Characteristic parameters of mathematical models for drop behavior on triturated preparations have been calculated. Contamination with hydrocarbons has resulted in a reliable increase in the contact angles of soil preparations. The hydrophobization of soil surface in chernozem is more active than in soils poorer in organic matter. The complete restoration of the hydrophilic properties of soils after hydrocarbon contamination is due to the oxidation of easily oxidizable organic matter at the low content of humus, or to wetting during several months in the absence of the mazut fraction.

  16. Novel atmospheric pressure plasma device releasing atomic hydrogen: reduction of microbial-contaminants and OH radicals in the air

    NASA Astrophysics Data System (ADS)

    Nojima, Hideo; Park, Rae-Eun; Kwon, Jun-Hyoun; Suh, Inseon; Jeon, Junsang; Ha, Eunju; On, Hyeon-Ki; Kim, Hye-Ryung; Choi, Kyoung Hui; Lee, Kwang-Hee; Seong, Baik-Lin; Jung, Hoon; Kang, Shin Jung; Namba, Shinichi; Takiyama, Ken

    2007-01-01

    A novel atmospheric pressure plasma device releasing atomic hydrogen has been developed. This device has specific properties such as (1) deactivation of airborne microbial-contaminants, (2) neutralization of indoor OH radicals and (3) being harmless to the human body. It consists of a ceramic plate as a positive ion generation electrode and a needle-shaped electrode as an electron emission electrode. Release of atomic hydrogen from the device has been investigated by the spectroscopic method. Optical emission of atomic hydrogen probably due to recombination of positive ions, H+(H2O)n, generated from the ceramic plate electrode and electrons emitted from the needle-shaped electrode have been clearly observed in the He gas (including water vapour) environment. The efficacy of the device to reduce airborne concentrations of influenza virus, bacteria, mould fungi and allergens has been evaluated. 99.6% of airborne influenza virus has been deactivated with the operation of the device compared with the control test in a 1 m3 chamber after 60 min. The neutralization of the OH radical has been investigated by spectroscopic and biological methods. A remarkable reduction of the OH radical in the air by operation of the device has been observed by laser-induced fluorescence spectroscopy. The cell protection effects of the device against OH radicals in the air have been observed. Furthermore, the side effects have been checked by animal experiments. The harmlessness of the device has been confirmed.

  17. Manganese concentrations in the soil and air in the vicinity of a closed manganese alloy production plant.

    PubMed

    Boudissa, Soraya M; Lambert, Jean; Müller, Caroline; Kennedy, Greg; Gareau, Lise; Zayed, Joseph

    2006-05-15

    In Montreal (Canada), the mean annual atmospheric Mn concentrations between 1981 and 1990 were stable, followed by a decrease of almost 50% from 1990 to 1992. The reason for such a decrease in Mn is probably the shutdown of a large manganese alloy production plant in Beauharnois, approximately 25 km from Montreal. The objective of this study is to assess the level of air and soil contamination by Mn in the vicinity of this ferroalloy plant more than 10 years after its closure. Air and soil were sampled over 5 days at two and three sites, respectively. Site 1 was located 10 m NE of the closed plant, in the direction of the prevailing SW-NE winds. Sites 2 and 3 were at 50 and 800 m SE from the plant. Air samples were collected in order to determine total (MnT) and respirable (MnR). Soil samples were taken in the surface and subsurface strata. The results show that site 1 is extremely polluted with a mean Mn concentration in surface strata of 2,66,000+/-45,000 ppm and 2,83,000+/-23,000 ppm in the subsurface strata, while the average MnT and MnR are 21.9+/-13.7 and 3.5+/-3.9 microg/m(3), respectively. The explanation for this contamination is direct deposition on the soil of solid Mn-rich residue and atmospheric erosion of Mn particles. The situation should be remediated by the public authority with high priority.

  18. Modelling the concentrations of dissolved contaminants (Cd, Cu, Ni, Pb, Zn) in floodplain soils.

    PubMed

    Rennert, Thilo; Rabus, Widar; Rinklebe, Jörg

    2016-07-29

    Central European floodplain soils are often contaminated with potentially toxic metals. The prediction of their aqueous concentrations is a prerequisite for an assessment of environmental concerns. We tested the aqueous concentrations of cadmium (Cd), copper (Cu), nickel (Ni), lead (Pb) and zinc (Zn) derived from multi-surface adsorption modelling (on hydrous iron, aluminum and manganese oxides, clay and soil organic matter) against those analyzed in situ in the soil solution of four horizons of floodplain soils at the Elbe River, Germany. The input data for the reactive metals were derived from a seven-step sequential extraction scheme or from extraction with 0.43 M nitric acid (HNO3) and evaluated in four modelling scenarios. In all scenarios, measured and modelled concentrations were positively related, except partially for Pb. Close reproduction of the measured data was obtained using measured data of accompanying cations and anions together with amounts of reactive metals from both the sequential extraction or from 0.43 M HNO3 extraction, except for Cu, which was often strongly overestimated, and partially Cd. We recommend extraction with 0.43 M HNO3 to quantify reactive metals in soil because the modelling results were metal-specific with better or equal results using the single extractant, the application of which is also less laborious. Approximations of ion concentrations and water contents yielded similar results. Modelled solid-phase speciation of metals varied with pH and differed from that from sequential extraction. Multi-surface modelling may be an effective tool to predict both aqueous concentrations and solid-phase speciation of metals in soil.

  19. Effect of sulphur concentration on bioleaching of heavy metals from contaminated dredged sediments.

    PubMed

    Fang, D; Zhao, L; Yang, Z Q; Shan, H X; Gao, Y; Yang, Q

    2009-11-01

    The sulphur-based bioleaching process using sulphur-oxidizing bacteria (SOB) has been demonstrated to be a feasible technology for removing heavy metals from contaminated sediments, but the excess sulphur application will lead to the re-acidification of bioleached sediments. The objective of the present study was to examine the effect of sulphur concentration on the bioleaching of heavy metals from contaminated sediments, with the ultimate purpose of minimizing the sulphur addition. The results showed that the inoculation of 7% of indigenous SOB, containing 3.6 x 10(8) colony forming units (CFU) mL(-1), and addition of elemental sulphur as a substrate (0.5 to 7.0 g L(-1)) resulted in a sharp decrease in sediment pH from an initial pH 8.0 to pH 1.4-2.4 and an increase in ORP (oxidation-reduction potential) from -10 mV to 500 mV within 10 days of bioleaching. Although the increase in sulphur concentration enhanced the rates of pH reduction and ORP elevation, the bioleaching process with the addition of 3.0 g L(-1) of sulphur was already sufficient to reach conditions of acidity (pH < 2.0) and ORP (500 mV) necessary for a satisfactory removal of metals, and, at day 10, 71.8% of Cu, 58.2% of Zn, and 25.3% of Cr were removed from the sediments. During the bioleaching process, Zn removal increased with a reduction in pH, whereas the removal of Cu and Cr increased not only with a reduction in pH but also with an increase in ORP. Results of sequential selective extraction indicated that the final levels of metal removals were dependent on their speciation distribution in the original sediments, and after bioleaching those unremoved metals in the bioleached sediments mainly existed in the residual fraction.

  20. Concentrations in air of organobromine, organochlorine and organophosphate flame retardants in Toronto, Canada

    NASA Astrophysics Data System (ADS)

    Shoeib, Mahiba; Ahrens, Lutz; Jantunen, Liisa; Harner, Tom

    2014-12-01

    Concentrations of organobromine (BFRs), organochlorine (CFRs) and organophosphate esters flame retardants and plasticizers (PFRs) in air were monitored for over one year at an urban site in Toronto, Canada during 2010-2011. The mean value for polybrominated diphenyl ethers (BDEs) (gas + particle phase) was 38 pg/m3 with BDE-47 and BDE-99 as the dominant congeners. The mean concentrations in air for ∑non-BDE (BFRs and CFRs), was 9.6 pg/m3 - about four times lower than the BDEs. The brominated FRs: TBP-AE, BTBPE, EH-TBB, BEH-TEBP and the chlorinated syn- and anti-DP were detected frequently, ranging from 87% to 96%. Highest concentrations in air among all flame retardant classes were observed for the Σ-PFRs. The yearly mean concentration in air for ΣPFRs was 2643 pg/m3 with detection frequency higher than 80%. Except for TBP-AE and b- DBE-DBCH, non-BDEs (BFRs, CFRs and PFRs) were mainly associated with the particle phase. BDE concentrations in air were positively correlated with temperature indicating that volatilization from local sources was an important factor controlling levels in air. This correlation did not hold for most BFRs, CFRs and PFRs which were mainly on particles. For these compounds, air concentrations in Toronto are likely related to emissions from point sources and advective inputs. This study highlights the importance of urban air monitoring for FRs. Urban air can be considered a sentinel for detecting changes in the use and application of FRs in commercial products.

  1. Tissue mercury concentrations and adrenocortical responses of female big brown bats (Eptesicus fuscus) near a contaminated river.

    PubMed

    Wada, Haruka; Yates, David E; Evers, David C; Taylor, Robert J; Hopkins, William A

    2010-10-01

    Much of the research on mercury (Hg) in wild vertebrates has focused on piscivores and other animals at high trophic levels. However, recent studies indicated that insectivorous terrestrial vertebrates may also be at risk. In the present study, we examined blood and fur Hg concentrations as well as the adrenocortical responses of insectivorous big brown bats (Eptesicus fuscus) near the Hg-contaminated South River, VA and a nearby reference area. Baseline glucocorticoids and adrenocortical responses to handling have been widely used to assess the influence of environmental stressors because plasma glucocorticoids rise in response to various physical, psychological, and physiological challenges. Female bats captured at the contaminated site had 2.6 times higher blood and fur Hg concentrations than those captured at the reference site (blood: 0.11 vs. 0.04 μg/g wet weight; fur: 28.0 vs. 10.9 μg/g fresh weight). Fur Hg concentrations at the contaminated site were higher than most wild omnivorous and carnivorous mammals reported in the literature. Although fur and blood Hg concentrations were tightly correlated, fur Hg concentrations averaged 260 times higher than concentrations in blood. This suggests that fur may be an important depuration route for bats, just as it is in other mammals. Despite the high Hg concentrations in bat tissue, we did not observe any site difference in adrenocortical responses. Our results suggest that the bats at the contaminated site were exposed to Hg concentrations below those causing adverse effects on their adrenal axis.

  2. 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...

  3. Polychlorinated biphenyls (PCBs) in air and soil from a high-altitude pasture in the Italian Alps: evidence of CB-209 contamination.

    PubMed

    Tremolada, Paolo; Guazzoni, Niccolò; Comolli, Roberto; Parolini, Marco; Lazzaro, Serena; Binelli, Andrea

    2015-12-01

    This study analyses the seasonal trend of polychlorinated biphenyls (PCB) concentrations in air and soil from a high-altitude mountain pasture in the Italian Alps. PCB concentrations in soil were generally comparable to background levels and were lower than those previously measured in the same area. Only CB-209 unexpectedly showed high concentrations with respect to the other congeners. GC-MS-MS identification was very clear, rising a new problem of increasing PCB contamination concerning only CB-209, which is not present in commercial mixtures used in the past in Italy and Europe. Considering all of the congeners, seasonal PCB trends were observed both in air and in soil that were related to the temperature and precipitation measured specifically in the study area. Highly significant relationships were found between the temperature-normalised concentrations in soil and the precipitation amounts. A north/south enrichment factor was present only in soil with rapid early summer re-volatilisation kinetics from soil to air and autumn re-deposition events from air to soil. Fugacity ratio calculations confirmed these trends. Surface soils respond rapidly to meteorological variables, while subsurface soils respond much more slowly. Seasonal trends were different for the northern and southern sides of the mountain. A detailed picture of the interactions among temperature, precipitation, mountain aspects and soil features was obtained.

  4. Investigation of the concentration of bacteria and their cell envelope components in indoor air in two elementary schools.

    PubMed

    Liu, L J; Krahmer, M; Fox, A; Feigley, C E; Featherstone, A; Saraf, A; Larsson, L

    2000-11-01

    Bacterial cell envelope components are widely distributed in airborne dust, where they act as inflammatory agents causing respiratory symptoms. Measurements of these agents and other environmental factors are assessed in two elementary schools in a southeastern city in the United States. Muramic acid (MA) was used as a marker for bacterial peptidoglycan (PG), and 3-hydroxy fatty acids (3-OH FAs) were used as markers for Gram-negative bacterial lipopolysaccharide (LPS). Culturable bacteria were collected using an Andersen sampler with three different culture media. In addition, temperature (T), relative humidity (RH), and CO2 were continuously monitored. Concentrations of airborne MA and 3-OH FAs were correlated with total suspended particulate (TSP) levels. Outdoor MA (mean = 0.78-1.15 ng/m3) and 3-OH FA levels (mean = 2.19-2.18 ng/m3) were similar at the two schools. Indoor concentrations of airborne MA and 3-OH FAs differed significantly between schools (MA: 1.44 vs. 2.84 ng/m3; 3-OH FAs: 2.96 vs. 4.57 ng/m3). Although indoor MA levels were low, they were significantly related to teachers' perception of the severity of indoor air quality (IAQ) problems in their classrooms. Concentrations of CO2 correlated significantly with all bacteria measurements. Because CO2 levels were related to the number of occupants and the ventilation rates, these findings are consistent with the hypothesis that the children and teachers are sources of bacterial contamination. Many culturable bacteria present in indoor air are opportunistic organisms that can be infectious for compromised individuals, while both culturable and nonculturable bacterial remnants act as environmental toxins for both healthy and compromised individuals. Measuring the "total bacteria load" would be most accurate in assessing the biotoxicity of indoor air. Chemical analysis of MA and 3-OH FAs, when coupled with the conventional culture method, provides complementary information for assessing biocontamination

  5. Opposed jet burner studies of hydrogen combustion with pure and N2, NO-contaminated air

    NASA Technical Reports Server (NTRS)

    Guerra, Rosemary; Pellett, Gerald L.; Northam, G. Burton; Wilson, Lloyd G.

    1987-01-01

    A counterflow diffusion flame formed by an argon-bathed tubular-opposed jet burner (OJB) was used to determine the 'blowoff' and 'restore' combustion characteristics for jets of various H2/N2 mixtures and for jets of air contaminated by NO (which normally occurs in high-enthalpy airflows supplied to hypersonic test facilities for scramjet combustors). Substantial divergence of 'blowoff' and 'restore' limits occurred as H2 mass flux, M(H)2, increased, the H2 jet became richer, and the M(air)/M(H2 + N2) ratio increased from 1 to 3 (molar H2/O2 from 1 to 16). Both OJB limits were sensitive to reactant composition. One to six percent NO in air led to significant N2-corrected decreases in the M(H2) values for 'blowoff' (2-8 percent) and 'restore' (6-12 percent) for mole fractions of H2 ranging from 0.5 to 0.95. However, when H2/O2 was held constant, all N2-corrected changes in M(H2) were negligible.

  6. Trend and climate signals in seasonal air concentration of organochlorine pesticides over the Great Lakes

    NASA Astrophysics Data System (ADS)

    Gao, Hong; Ma, Jianmin; Cao, Zuohao; Dove, Alice; Zhang, Lisheng

    2010-08-01

    Following worldwide bans or restrictions, the atmospheric level of many organochlorine pesticides (OCPs) over the Great Lakes exhibited a decreasing trend since the 1980s in various environmental compartments. Atmospheric conditions also influence variation and trend of OCPs. In the present study a nonparametric Mann-Kendall test with an additional process to remove the effect of temporal (serial) correlation was used to detect the temporal trend of OCPs in the atmosphere over the Great Lakes region and to examine the statistical significance of the trends. Using extended time series of measured air concentrations over the Great Lakes region from the Integrated Atmospheric Deposition Network, this study also revisits relationships between seasonal mean air concentration of OCPs and major climate variabilities in the Northern Hemisphere. To effectively extract climate signals from the temporal trend of air concentrations, we detrended air concentrations through removing their linear trend, which is driven largely by their respective half-lives in the atmosphere. The interannual variations of the extended time series show a good association with interannual climate variability, notably, the North Atlantic Oscillation (NAO) and the El Niño-Southern Oscillation. This study demonstrates that the stronger climate signals can be extracted from the detrended time series of air concentrations of some legacy OCPs. The detrended concentration time series also help to interpret, in addition to the connection with interannual variation of the NAO, the links between atmospheric concentrations of OCPs and decadal or interdecadal climate change.

  7. Predictors of Indoor Air Concentrations in Smoking and Non-Smoking Residences

    PubMed Central

    Héroux, Marie-Eve; Clark, Nina; Van Ryswyk, Keith; Mallick, Ranjeeta; Gilbert, Nicolas L.; Harrison, Ian; Rispler, Kathleen; Wang, Daniel; Anastassopoulos, Angelos; Guay, Mireille; MacNeill, Morgan; Wheeler, Amanda J.

    2010-01-01

    Indoor concentrations of air pollutants (benzene, toluene, formaldehyde, acetaldehyde, acrolein, nitrogen dioxide, particulate matter, elemental carbon and ozone) were measured in residences in Regina, Saskatchewan, Canada. Data were collected in 106 homes in winter and 111 homes in summer of 2007, with 71 homes participating in both seasons. In addition, data for relative humidity, temperature, air exchange rates, housing characteristics and occupants’ activities during sampling were collected. Multiple linear regression analysis was used to construct season-specific models for the air pollutants. Where smoking was a major contributor to indoor concentrations, separate models were constructed for all homes and for those homes with no cigarette smoke exposure. The housing characteristics and occupants’ activities investigated in this study explained between 11% and 53% of the variability in indoor air pollutant concentrations, with ventilation, age of home and attached garage being important predictors for many pollutants. PMID:20948949

  8. Phytoremediation of benzene, toluene, ethylbenzene and xylene contaminated air by D. deremensis and O. microdasys plants

    PubMed Central

    2014-01-01

    Background People usually spent about 90% of their time indoors, which are probably more polluted than outside the buildings. High levels of volatile organic compounds (VOCs) are known as causes of sick building syndrome. The present study was designed to determine the quantitative effects of some plants to improve the quality of the environmental air. Results D. deremensis and O. microdasys were chosen for the present study. There is no report of using O. microdasys for cleaning the air from pollutants. So, in this study, the effectiveness of O. microdasys in air removing from pollutants was studied and compared with D. dermensis. O. microdasys plant can remove 2 ppm concentration benzene, toluene, xylene and ethylbenzene from air in test chambers completely after 48, 55, 47 and 57 hours, respectively. The removal rates of benzene, toluene, xylene and ethylbenzene (BTEX) from air in the test chambers were 1.18, 0.54, 1.64 and 1.35 mg/ m2d1, respectively. Conclusions If an office containing 2.5 ppm of each of BTEX and had an approximate volume of 30 m3, it contains 16, 8, 22 and 22 mg/m3 benzene, toluene, xylene and ethylbenzene, respectively. Using ten O. microdasys pots with the same size used in this study, can remove benzene, toluene, xylene and ethylbenzene totally after 36, 40, 30 and 39 hours. The authors recommended studying the efficiency of the plants for removal of BTEX from air at higher range of concentrations such as 20-30 ppm. PMID:24451679

  9. An Evaluation of Antifungal Agents for the Treatment of Fungal Contamination in Indoor Air Environments

    PubMed Central

    Rogawansamy, Senthaamarai; Gaskin, Sharyn; Taylor, Michael; Pisaniello, Dino

    2015-01-01

    Fungal contamination in indoor environments has been associated with adverse health effects for the inhabitants. Remediation of fungal contamination requires removal of the fungi present and modifying the indoor environment to become less favourable to growth.  This may include treatment of indoor environments with an antifungal agent to prevent future growth. However there are limited published data or advice on chemical agents suitable for indoor fungal remediation. The aim of this study was to assess the relative efficacies of five commercially available cleaning agents with published or anecdotal use for indoor fungal remediation. The five agents included two common multi-purpose industrial disinfectants (Cavicide® and Virkon®), 70% ethanol, vinegar (4.0%−4.2% acetic acid), and a plant-derived compound (tea tree (Melaleuca alternifolia) oil) tested in both a liquid and vapour form. Tea tree oil has recently generated interest for its antimicrobial efficacy in clinical settings, but has not been widely employed for fungal remediation. Each antifungal agent was assessed for fungal growth inhibition using a disc diffusion method against a representative species from two common fungal genera, (Aspergillus fumigatus and Penicillium chrysogenum), which were isolated from air samples and are commonly found in indoor air. Tea tree oil demonstrated the greatest inhibitory effect on the growth of both fungi, applied in either a liquid or vapour form. Cavicide® and Virkon® demonstrated similar, although less, growth inhibition of both genera. Vinegar (4.0%–4.2% acetic acid) was found to only inhibit the growth of P. chrysogenum, while 70% ethanol was found to have no inhibitory effect on the growth of either fungi. There was a notable inhibition in sporulation, distinct from growth inhibition after exposure to tea tree oil, Virkon®, Cavicide® and vinegar. Results demonstrate that common cleaning and antifungal agents differ in their capacity to inhibit the

  10. An evaluation of antifungal agents for the treatment of fungal contamination in indoor air environments.

    PubMed

    Rogawansamy, Senthaamarai; Gaskin, Sharyn; Taylor, Michael; Pisaniello, Dino

    2015-06-02

    Fungal contamination in indoor environments has been associated with adverse health effects for the inhabitants. Remediation of fungal contamination requires removal of the fungi present and modifying the indoor environment to become less favourable to growth.  This may include treatment of indoor environments with an antifungal agent to prevent future growth. However there are limited published data or advice on chemical agents suitable for indoor fungal remediation. The aim of this study was to assess the relative efficacies of five commercially available cleaning agents with published or anecdotal use for indoor fungal remediation. The five agents included two common multi-purpose industrial disinfectants (Cavicide® and Virkon®), 70% ethanol, vinegar (4.0%-4.2% acetic acid), and a plant-derived compound (tea tree (Melaleuca alternifolia) oil) tested in both a liquid and vapour form. Tea tree oil has recently generated interest for its antimicrobial efficacy in clinical settings, but has not been widely employed for fungal remediation. Each antifungal agent was assessed for fungal growth inhibition using a disc diffusion method against a representative species from two common fungal genera, (Aspergillus fumigatus and Penicillium chrysogenum), which were isolated from air samples and are commonly found in indoor air. Tea tree oil demonstrated the greatest inhibitory effect on the growth of both fungi, applied in either a liquid or vapour form. Cavicide® and Virkon® demonstrated similar, although less, growth inhibition of both genera. Vinegar (4.0%-4.2% acetic acid) was found to only inhibit the growth of P. chrysogenum, while 70% ethanol was found to have no inhibitory effect on the growth of either fungi. There was a notable inhibition in sporulation, distinct from growth inhibition after exposure to tea tree oil, Virkon®, Cavicide® and vinegar. Results demonstrate that common cleaning and antifungal agents differ in their capacity to inhibit the growth

  11. Evolution of HTO concentrations in soil, vegetation and air during an experimental chronic HT release

    SciTech Connect

    Davis, P.A.; Galeriu, D.C.; Spencer, F.S.; Amiro, B.D.

    1995-10-01

    A small experimental plot was continuously exposed to elevated levels of HT in air over a 12-day period to study the build up and steady-state concentrations of HTO in the environment. HTO concentrations in soil, vegetation and air all showed similar dynamics, increasing gradually over time with temporary decreases during and following rainfall. The relative magnitudes of the soil, vegetation and air concentrations depended on the height at which the air and vegetation were sampled, the depth at which the soil sample was taken and the soil depth over which the plants drew their transpiration water. The system was at or near steady-state in the last two or three days of the release. When averaged over an eight day interval that included periods of rain, the ratios of HTO concentration in soil, foliage and air moisture to HT concentration in air (measured 20 cm above the ground) were typically 0.0014, 0.0010 and 0.0011 (Bq/mL)/(Bq/m{sup 3}) for a cultivated field. 10 refs., 7 figs.

  12. THE THREE INTERACTING FACTORS ASSOCIATED WITH CHILDREN'S DIETARY EXPOSURES: ENVIRONMENTAL CONCENTRATIONS, FOOD CONTAMINATION, AND CHILDREN'S BEHAVIORS

    EPA Science Inventory

    The dietary contribution to an aggregate exposure assessment is potentially an important pathway of exposure especially for young children. Enviornmental contamination appearing in the child's diet can result from contamination in the food as purchased or due to preparing, servin...

  13. CONTAMINANT CONCENTRATIONS IN WHOLE-BODY FISH AND SHELLFISH FROM U.S. ESTUARIES

    EPA Science Inventory

    Persistent bioaccumulative and toxic (PBT) pollutants are chemical contaminants that pose risks to ecosystems and human health. For these reasons, available tissue contaminant data from the US EPA Environmental Monitoring and Assessment Program's National Coastal Assessment were...

  14. Performance of Passive Samplers for Monitoring Estuarine Water Column Concentrations: 1. Contaminants of Concern

    EPA Science Inventory

    Contaminants enter marine and estuarine environments and can potentially pose risk to human and ecological health. Measuring contaminants of concern (COC) in these aqueous media can be difficult due to their relatively low solubilities and tendency to associate with environmenta...

  15. An assessment of ozone concentrations within and near the Lake Tahoe Air Basin

    NASA Astrophysics Data System (ADS)

    Dolislager, Leon J.; VanCuren, Richard; Pederson, James R.; Lashgari, Ash; McCauley, Eileen

    2012-01-01

    The Lake Tahoe Atmospheric Deposition Study (LTADS) was conducted by the Air Resources Board of the State of California (CARB) primarily to generate refined estimates of the atmospheric deposition of nitrogen, phosphorous, and particulate matter directly to Lake Tahoe, which straddles the border between the states of California and Nevada near Reno, Nevada. The enhanced air quality monitoring during LTADS also included ozone measurements, which yielded additional insights into atmospheric processes and the role of transport in determining ozone concentrations within the Lake Tahoe Air Basin. The Lake Tahoe Air Basin is located generally downwind of air basins with major emissions of ozone precursors (e.g., VOCs, NOx), capable of generating significant ozone concentrations. Furthermore, vegetation on the western slope of the Sierra Nevada contribute biogenic organic compounds to the air mass. Ozone concentrations within the Tahoe Basin infrequently exceed the local 1-h threshold set to protect forest health (0.08 ppm) and the California 8-h ambient air quality standard (0.070 ppm). A concern then is the potential contribution of regional emission sources to the ozone concentrations observed in the Tahoe Basin. The ozone data collected during LTADS helped to better characterize the relative contribution of local and regional pollution sources to ozone air quality within the Tahoe Basin. The data indicate potential 1- or 2-day intact transport on rare occasions but generally the mixing of the atmosphere over the Sierra Nevada disperses the anthropogenic ozone throughout the boundary layer, which is generally more than a kilometer or two deep during the day. The data analysis indicates that emissions from upwind air basins add to the atmospheric burden of ozone concentrations, raising the regional concentrations in the Sierra Nevada. Given the large background and upwind enhancements relative to the ambient air quality standards, the local contribution does not need to

  16. Evaluation of bacterial contamination on surgical drapes following use of the Bair Hugger(®) forced air warming system.

    PubMed

    Occhipinti, Lindsay L; Hauptman, Joe G; Greco, Justin J; Mehler, Stephen J

    2013-12-01

    This pilot study determined the rate of bacterial contamination on surgical drapes of small animal patients warmed intra-operatively with the Bair Hugger(®) forced air warming system compared to a control method. Surgical drapes of 100 patients undergoing clean surgical procedures were swabbed with aerobic culturettes at the beginning and end of surgery. Samples were cultured on Trypticase soy agar. Contamination of the surgical drapes was identified in 6/98 cases (6.1%). There was no significant difference in the number of contaminated surgical drapes between the Bair Hugger(®) and control groups (P = 0.47).

  17. CONCENTRATED AMBIENT AIR PARTICLES INDUCE PULMONARY INFLAMMATION IN HEALTHY HUMAN VOLUNTEERS

    EPA Science Inventory


    We tested the hypothesis that exposure of healthy volunteers to concentrated ambient particles (CAPS) is associated with an influx of inflammatory cells into the lower respiratory tract. Thirty-eight volunteers were exposed to either filtered air or particles concentrated fro...

  18. COMPARISON OF MOLD CONCENTRATIONS IN INDOOR AND OUTDOOR AIR SAMPLED SIMULTANEOUSLY AND THEN QUANTIFIED BY MSQPCR

    EPA Science Inventory

    Mold specific quantitative PCR (MSQPCR) was used to measure the concentrations of the 36 mold species in indoor and outdoor air samples that were taken simultaneously for 48 hours in and around 17 homes in Cincinnati, Ohio. The total spore concentrations of 353 per m3...

  19. Sensitivity of Hollow Fiber Spacesuit Water Membrane Evaporator Systems to Potable Water Constituents, Contaminants and Air Bubbles

    NASA Technical Reports Server (NTRS)

    Bue, Grant C.; Trevino, Luis A.; Fritts, Sharon; Tsioulos, Gus

    2008-01-01

    The Spacesuit Water Membrane Evaporator (SWME) is the baseline heat rejection technology selected for development for the Constellation lunar suit. The first SWME prototype, designed, built, and tested at Johnson Space Center in 1999 used a Teflon hydrophobic porous membrane sheet shaped into an annulus to provide cooling to the coolant loop through water evaporation to the vacuum of space. This present study describes the test methodology and planning and compares the test performance of three commercially available hollow fiber materials as alternatives to the sheet membrane prototype for SWME, in particular, a porous hydrophobic polypropylene, and two variants that employ ion exchange through non-porous hydrophilic modified Nafion. Contamination tests will be performed to probe for sensitivities of the candidate SWME elements to ordinary constituents that are expected to be found in the potable water provided by the vehicle, the target feedwater source. Some of the impurities in potable water are volatile, such as the organics, while others, such as the metals and inorganic ions are nonvolatile. The non-volatile constituents will concentrate in the SWME as evaporated water from the loop is replaced by the feedwater. At some point in the SWME mission lifecycle as the concentrations of the non-volatiles increase, the solubility limits of one or more of the constituents may be reached. The resulting presence of precipitate in the coolant water may begin to plug pores and tube channels and affect the SWME performance. Sensitivity to macroparticles, lunar dust simulant, and air bubbles will also be investigated.

  20. Investigation of ground-water contamination at a drainage ditch, Installation Restoration Site 4, Naval Air Station Corpus Christi, Corpus Christi, Texas, 2005–06

    USGS Publications Warehouse

    Vroblesky, Don A.; Casey, Clifton C.

    2007-01-01

    The U.S. Geological Survey, in cooperation with the Naval Facilities Engineering Command Southeast, used newly developed sampling methods to investigate ground-water contamination by chlorobenzenes beneath a drainage ditch on the southwestern side of Installation Restoration Site 4, Naval Air Station Corpus Christi, Corpus Christi, Texas, during 2005-06. The drainage ditch, which is a potential receptor for ground-water contaminants from Installation Restoration Site 4, intermittently discharges water to Corpus Christi Bay. This report uses data from a new type of pore-water sampler developed for this investigation and other methods to examine the subsurface contamination beneath the drainage ditch. Analysis of ground water from the samplers indicated that chlorobenzenes (maximum detected concentration of 160 micrograms per liter) are present in the ground water beneath the ditch. The concentrations of dissolved oxygen in the samples (less than 0.05-0.4 milligram per liter) showed that the ground water beneath and near the ditch is anaerobic, indicating that substantial chlorobenzene biodegradation in the aquifer beneath the ditch is unlikely. Probable alternative mechanisms of chlorobenzene removal in the ground water beneath the drainage ditch include sorption onto the organic-rich sediment and contaminant depletion by cattails through uptake, sorption, and localized soil aeration.

  1. Actual measurement, hygrothermal response experiment and growth prediction analysis of microbial contamination of central air conditioning system in Dalian, China

    PubMed Central

    Lv, Yang; Hu, Guangyao; Wang, Chunyang; Yuan, Wenjie; Wei, Shanshan; Gao, Jiaoqi; Wang, Boyuan; Song, Fangchao

    2017-01-01

    The microbial contamination of central air conditioning system is one of the important factors that affect the indoor air quality. Actual measurement and analysis were carried out on microbial contamination in central air conditioning system at a venue in Dalian, China. Illumina miseq method was used and three fungal samples of two units were analysed by high throughput sequencing. Results showed that the predominant fungus in air conditioning unit A and B were Candida spp. and Cladosporium spp., and two fungus were further used in the hygrothermal response experiment. Based on the data of Cladosporium in hygrothermal response experiment, this paper used the logistic equation and the Gompertz equation to fit the growth predictive model of Cladosporium genera in different temperature and relative humidity conditions, and the square root model was fitted based on the two environmental factors. In addition, the models were carried on the analysis to verify the accuracy and feasibility of the established model equation. PMID:28367963

  2. Opposed jet burner studies of effects of CO, CO2, and N2 air-contaminants on hydrogen-air diffusion flames

    NASA Technical Reports Server (NTRS)

    Guerra, Rosemary; Pellett, Gerald L.; Northam, G. Burton; Wilson, Lloyd G.

    1987-01-01

    The blowoff/restore characteristics for jets of various H2/N2 mixtures opposed to jets of air contaminated by N2, CO, and CO2 have been determined using a counterflow diffusion flame formed by a tubular opposed jet burner. Both blowoff and restore limits are found to be sensitive to fuel and air composition. Empirically derived variations in the limits of the average mass flux of incoming H2 with percent contaminant, at fixed incoming fuel and H2/O2 inputs, are used to quantify the effects of oxygen dilution, flame augmentation, and flame retardation by N2, CO, and CO2 contaminants. The implications of the results are discussed.

  3. Prediction of Air Pollutants Concentration Based on an Extreme Learning Machine: The Case of Hong Kong

    PubMed Central

    Zhang, Jiangshe; Ding, Weifu

    2017-01-01

    With the development of the economy and society all over the world, most metropolitan cities are experiencing elevated concentrations of ground-level air pollutants. It is urgent to predict and evaluate the concentration of air pollutants for some local environmental or health agencies. Feed-forward artificial neural networks have been widely used in the prediction of air pollutants concentration. However, there are some drawbacks, such as the low convergence rate and the local minimum. The extreme learning machine for single hidden layer feed-forward neural networks tends to provide good generalization performance at an extremely fast learning speed. The major sources of air pollutants in Hong Kong are mobile, stationary, and from trans-boundary sources. We propose predicting the concentration of air pollutants by the use of trained extreme learning machines based on the data obtained from eight air quality parameters in two monitoring stations, including Sham Shui Po and Tap Mun in Hong Kong for six years. The experimental results show that our proposed algorithm performs better on the Hong Kong data both quantitatively and qualitatively. Particularly, our algorithm shows better predictive ability, with R2 increased and root mean square error values decreased respectively. PMID:28125034

  4. Prediction of Air Pollutants Concentration Based on an Extreme Learning Machine: The Case of Hong Kong.

    PubMed

    Zhang, Jiangshe; Ding, Weifu

    2017-01-24

    With the development of the economy and society all over the world, most metropolitan cities are experiencing elevated concentrations of ground-level air pollutants. It is urgent to predict and evaluate the concentration of air pollutants for some local environmental or health agencies. Feed-forward artificial neural networks have been widely used in the prediction of air pollutants concentration. However, there are some drawbacks, such as the low convergence rate and the local minimum. The extreme learning machine for single hidden layer feed-forward neural networks tends to provide good generalization performance at an extremely fast learning speed. The major sources of air pollutants in Hong Kong are mobile, stationary, and from trans-boundary sources. We propose predicting the concentration of air pollutants by the use of trained extreme learning machines based on the data obtained from eight air quality parameters in two monitoring stations, including Sham Shui Po and Tap Mun in Hong Kong for six years. The experimental results show that our proposed algorithm performs better on the Hong Kong data both quantitatively and qualitatively. Particularly, our algorithm shows better predictive ability, with R 2 increased and root mean square error values decreased respectively.

  5. Radial metal concentration profiles in trees growing on highly contaminated soils.

    PubMed

    Superville, Pierre-Jean; de Winter, Niels; Phung, Anh Tuan; Proix, Nicolas; Baeyens, Willy; Gao, Yue

    2017-04-01

    The soil around Metaleurop, a big smelter, is heavily contaminated by Zn, Pb, Cd and Cu. In order to compare the impact of different soil amendments on the metal availability to trees, the polluted soil section was divided in a reference parcel and two others with either sulfo-calcic or silico-aluminous ash amendments. Five different tree species were planted on the parcels and the uptake of heavy metals in these trees was studied. Total and labile metal fractions were assessed in each of the 3 parcels. The mobility and assimilation of the metals was highest in the non-amended, reference soil parcel which had the lowest pH, organic matter and carbonate content. In all soils, pH decreased while organic matter content and mobility of the metals increased over time. Highest bulk concentrations of trace metals were found in white willow trees (Salix alba L.). Laser ablation-ICPMS was used to study changes in metal accumulation over a period of 10 years after planting the trees. The radial metal profiles in the trunk core samples varied between elements and tree species, however, in all willow trees the radial Cd and Zn profiles were significantly correlated. Radial pollutant concentration patterns are discussed in terms of seasonal effects, health status, tree species and metal mobility in the soil. For Cd and Zn, the profiles were influenced by their mobility in the soils. In general, periodical patterns were observed for Pb. Cu concentration profiles were decreasing over time, with the strongest decrease in the initial growth period.

  6. (Environmental investigation of ground water contamination at Wright-Patterson Air Force Base, Ohio)

    SciTech Connect

    Not Available

    1991-10-01

    In April 1990 Wright-Patterson Air Force Base (WPAFB) initiated an investigation to evaluate a potential CERCLA removal action to prevent, to the extent practicable, the migration of ground-water contamination in the Mad River Valley Aquifer within and across WPAFB boundaries. The action will be based on a Focused Feasibility Study with an Action Memorandum serving as a decision document that is subject to approval by the Ohio Environmental Protection Agency. The first phase (Phase 1) of this effort involves an investigation of ground-water contamination migrating across the southwest boundary of Area C and across Springfield Pike adjacent to Area B. Task 4 of Phase 1 is a field investigation to collect sufficient additional information to evaluate removal alternatives. The field investigation will provide information in the following specific areas of study: water-level data which will be used to permit calibration of the ground-water flow model to a unique time in history; and ground-water quality data which will be used to characterize the current chemical conditions of ground water.

  7. Hot air vapor extraction system for remediation of petroleum contaminated sites

    SciTech Connect

    Pal, D.; Karr, L.; Fann, S.; Mathews, A.P.; Price, P.A.; Linginemi, S.

    1996-12-01

    This paper describes the results of a demonstration of a technology entitled ``Hot Air Vapor Extraction (HAVE)`` at the Hydrocarbon National Test Site (HNTS), Port Hueneme, California. The demonstration of the HAVE technology at HNTS was conducted over a 3-month period between August 21, 1995 and November 22, 1995 and the lessons learned from the demonstration are discussed in details to guide the Department of Defense decision makers in analyzing the applicability of this technology to their contaminated sites. This technology demonstration was conducted under the Department of Defense Strategic Environmental Research and Development Program (SERDP) as part of the National Environmental Technology Demonstration Program (NETDP). The primary objectives of the demonstration were to (1) validate the efficacy of the HAVE technology to treat a wide range of hydrocarbons contaminated soils, (2) gather data to estimate treatment costs, and (3) develop engineering guidance needed to apply this remediation technology DoD-wide. Test runs were made on 5 different treatment cells containing various fuel hydrocarbons, ranging from gasoline to heavier petroleum fractions such as lubricating oil. Computer modeling was conducted to analyze the test results and also to optimize the HAVE system design. An economic analysis conducted for various remediation project sizes ranging from 750 to 9,000 cubic yards, the per cubic yard treatment costs are found to vary from $64.05 down to $36.54 respectively.

  8. Development and Testing of an Air Fluorescence Imaging System for the Detection of Radiological Contamination

    SciTech Connect

    Inrig, Elizabeth; Koslowsky, Vern; Andrews, Bob; Dick, Michael; Forget, Patrick; Ing, Harry; Hugron, Roger; Wong, Larry

    2011-12-13

    Detection of radionuclides emitting short-range radiation, such as {alpha} and low-energy {beta} particles, has always presented a challenge, particularly when such radionuclides are dispersed over a wide area. In this situation, conventional detection methods require the area of interest to be surveyed using a fragile probe at very close range--a slow, error-prone, and potentially dangerous process that may take many hours for a single room. The instrument under development uses a novel approach by imaging radiation-induced fluorescence in the air surrounding a contaminated area, rather than detecting the radiation directly. A robust and portable system has been designed and built that will allow contaminated areas to be rapidly detected and delineated. The detector incorporates position-sensitive photo-multiplier tubes, UV filters, a fast electronic shutter and an aspherical phase mask that significantly increases the depth-of-field. Preliminary tests have been conducted using sealed {sup 241}Am sources of varying activities and surface areas. The details of the instrument design will be described and the results of recent testing will be presented.

  9. Studies of Contaminant Diffusion in an Aquitard and Groundwater Remediation by Reactive Metals at Dover Air Force Base, Delaware

    DTIC Science & Technology

    2007-11-02

    is unlimited. DESTRUCTION NOTICE - Destroy by any method that will prevent disclosure of contents or reconstruction of this document. AIR FORCE...research reported in this report relates to both of the above-stated concerns (better understanding of long-term contaminant fate and improved methods of...specific objectives outlined above, while taking best advantage of the previously developed facilities, methods , and understanding. No known Air Force

  10. Derivation and implementation of an annual limit on intake and a derived air concentration value for uranium mill tailings.

    PubMed

    Reif, R H; Andrews, D W

    1995-06-01

    Monitoring workers and work areas at the Department of Energy Uranium Mill Tailings Remedial Action Project sites is complex because all radionuclides in the 238U and 235U decay chains may be present in an airborne uranium mill tailings matrix. Previous monitoring practices involved isotopic analysis of the air filter to determine the activity of each radionuclide of concern and comparing the results to the specified derived air concentration. The annual limit on intake and derived air concentration values have been derived here for the uranium mill tailings matrix to simplify the procedure for evaluation of air monitoring results and assessment of the need for individual monitoring. Implementation of the derived air concentration for uranium mill tailings involves analyzing air samples for long-lived gross alpha activity and comparing the activity concentration to the derived air concentration. Health physics decisions regarding assessment of airborne concentrations is more cost-effective because isotopic analysis of air samples is not necessary.

  11. Effect of contaminant concentration on aerobic microbial mineralization of DCE and VC in stream-bed sediments

    USGS Publications Warehouse

    Bradley, P.M.; Chapelle, F.H.

    1998-01-01

    Discharge of DCE and VC to an aerobic surface water system simultaneously represents a significant environmental concern and, potentially, a non-engineered opportunity for efficient contaminant bioremediation. The potential for bioremediation, however, depends on the ability of the stream-bed microbial community to efficiently and completely degrade DCE and VC over a range of contaminant concentrations. The purposes of the studies reported here were to assess the potential for aerobic DCE and VC mineralization by stream-bed microorganisms and to evaluate the effects of DCE and VC concentrations on the apparent rates of aerobic mineralization. Bed-sediment microorganisms indigenous to a creek, where DCE-contaminated groundwater continuously discharges, demonstrated rapid mineralization of DCE and VC under aerobic conditions. Over 8 days, the recovery of [1,2-14C]DCE radioactivity as 14CO2 ranged from 17% to 100%, and the recovery of [1,2- 14C]VC radioactivity as 14CO2 ranged from 45% to 100%. Rates of DCE and VC mineralization increased significantly with increasing contaminant concentration, and the response of apparent mineralization rates to changes in DCE and VC concentrations was adequately described by Michaelis-Menten kinetics.Discharge of DCE and VC to an aerobic surface water system simultaneously represents a significant environmental concern and, potentially, a non-engineered opportunity for efficient contaminant bioremediation. The potential for bioremediation, however, depends on the ability of the stream-bed microbial community to efficiently and completely degrade DCE and VC over a range of contaminant concentrations. The purposes of the studies reported here were to assess the potential for aerobic DCE and VC mineralization by stream-bed microorganisms and to evaluate the effects of DCE and VC concentrations on the apparent rates of aerobic mineralization. Bed-sediment microorganisms indigenous to a creek, where DCE-contaminated groundwater

  12. Changes in surface area and concentrations of semivolatile organic contaminants in aging snow.

    PubMed

    Burniston, Debbie A; Strachan, William J M; Hoff, John T; Wania, Frank

    2007-07-15

    During the winter of 1999/2000 five snowpacks at Turkey Lake Watershed east of Lake Superior were sampled immediately after falling and again after several days of aging for the analysis of specific snow surface area and the concentrations of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs). The snow surface could be determined with a relative coefficient of variation of 6% using frontal chromatography, measuring the retention of ethyl acetate, a substance with known adsorption coefficient on the ice surface. The snow surface area of fresh snow varied from 1000 to 1330 cm2/g and was higher for snow falling during colder days. The aged snow samples had consistently lower surface areas ranging from 520 to 780 cm2/g, corresponding to an average loss of half of the initial surface area during aging. The rate of loss of surface area was faster at higher temperatures. Dieldrin, alpha-HCH, and gamma-HCH were the most abundant OCPs in snowmelt water, but endosulfan, chlordane-related substances, heptachlor epoxide, pp'-DDT, pp'-DDE, and chlorinated benzenes were also consistently present. Three midwinter snowpacks that aged during relatively cold temperatures generally experienced a loss of PCBs and OCPs that was of the same order of magnitude as the observed loss of snow surface area. However, no relationship between the extent of loss and the strength of a contaminants' sorption to snow was apparent. Few significant changes in snowpack concentrations of OCPs and PCBs were observed in a snowpack that fell at relatively high temperatures and aged under colder conditions. Concentrations of OCPs and PCBs increased in a late-winter snowpack that aged while temperatures rapidly increased to above freezing. Concentrations of pp'-DDE and endosulfan-II that increased in snowpacks that saw simultaneous decreases in the levels of pp'-DDT and endosulfan-I hint at the occurrence of sunlight induced conversions in snow. While surface area decreases clearly

  13. Methods to reduce the CO(2) concentration of educational buildings utilizing internal ventilation by transferred air.

    PubMed

    Kalema, T; Viot, M

    2014-02-01

    The aim of this study is to develop internal ventilation by transferred air to achieve a good indoor climate with low energy consumption in educational buildings with constant air volume (CAV) ventilation. Both measurements of CO2 concentration and a multi-room calculation model are presented. The study analyzes how to use more efficiently the available spaces and the capacity of CAV ventilation systems in existing buildings and the impact this has on the indoor air quality and the energy consumption of the ventilation. The temperature differences can be used to create natural ventilation airflows between neighboring spaces. The behavior of temperature-driven airflows between rooms was studied and included in the calculation model. The effect of openings between neighboring spaces, such as doors or large apertures in the walls, on the CO2 concentration was studied in different classrooms. The air temperatures and CO2 concentrations were measured using a wireless, internet-based measurement system. The multi-room calculation model predicted the CO2 concentration in the rooms, which was then compared with the measured ones. Using transferred air between occupied and unoccupied spaces can noticeably reduce the total mechanical ventilation rates needed to keep a low CO2 concentration.

  14. Historical Occupational Trichloroethylene Air Concentrations Based on Inspection Measurements From Shanghai, China

    PubMed Central

    Friesen, Melissa C.; Locke, Sarah J.; Chen, Yu-Cheng; Coble, Joseph B.; Stewart, Patricia A.; Ji, Bu-Tian; Bassig, Bryan; Lu, Wei; Xue, Shouzheng; Chow, Wong-Ho; Lan, Qing; Purdue, Mark P.; Rothman, Nathaniel; Vermeulen, Roel

    2015-01-01

    Purpose: Trichloroethylene (TCE) is a carcinogen that has been linked to kidney cancer and possibly other cancer sites including non-Hodgkin lymphoma. Its use in China has increased since the early 1990s with China’s growing metal, electronic, and telecommunications industries. We examined historical occupational TCE air concentration patterns in a database of TCE inspection measurements collected in Shanghai, China to identify temporal trends and broad contrasts among occupations and industries. Methods: Using a database of 932 short-term, area TCE air inspection measurements collected in Shanghai worksites from 1968 through 2000 (median year 1986), we developed mixed-effects models to evaluate job-, industry-, and time-specific TCE air concentrations. Results: Models of TCE air concentrations from Shanghai work sites predicted that exposures decreased 5–10% per year between 1968 and 2000. Measurements collected near launderers and dry cleaners had the highest predicted geometric means (GM for 1986 = 150–190mg m−3). The majority (53%) of the measurements were collected in metal treatment jobs. In a model restricted to measurements in metal treatment jobs, predicted GMs for 1986 varied 35-fold across industries, from 11mg m−3 in ‘other metal products/repair’ industries to 390mg m–3 in ‘ships/aircrafts’ industries. Conclusions: TCE workplace air concentrations appeared to have dropped over time in Shanghai, China between 1968 and 2000. Understanding differences in TCE concentrations across time, occupations, and industries may assist future epidemiologic studies in China. PMID:25180291

  15. Possible Causes of Decreasing Benzene Concentrations in an Oil-Contaminated Aquifer

    NASA Astrophysics Data System (ADS)

    Drennan, D.; Bekins, B. A.; Warren, E.; Baedecker, M. J.; Eganhouse, R. P.

    2010-12-01

    Crude oil contamination from a 1979 oil spill near Bemidji, Minnesota resulted in a subsurface oil body and a dissolved hydrocarbon plume in the groundwater. Benzene concentrations in the plume adjacent to the oil decreased from nearly 5 mg/L in 1993 to less than 3 mg/L in 2007. Benzene depletion within the plume and oil body was investigated with a microcosm study and analyses of the benzene content remaining in the oil. To test if the methanogenic microbial consortium adjacent to the oil is capable of degrading benzene, eight anaerobic microcosms were constructed with sediment from a methanogenic area of the plume that has been exposed to benzene. Microcosms were constructed in 120 mL serum bottles containing 60 g of anaerobic sediment, 20 mL pre-reduced mineral salts solution, and spiked with benzene to attain a target concentration of 2 mg/L. The methanogenic inhibitor, 2-bromoethanesulfonate (BES), was added to four bottles to achieve a concentration of 13.5 g/L. One bottle containing BES and another not containing BES were autoclaved. Over a year the average aqueous benzene concentrations decreased 2.9±0.4 μg/L-day in the inhibited microcosms, 3.1±0.3 μg/L-day in the uninhibited microcosms, and 2.1±0.5 μg/L-day in the autoclaved microcosms. Although the linear regressions slopes differed, the difference in the rates between the BES inhibited, uninhibited, and autoclaved treatments is not statistically significant with the existing data (p=0.19). Headspace analyses for methane conducted after 392 days showed concentrations in the uninhibited microcosms were about 40 times greater than the inhibited microcosms and autoclaved controls. The methane concentrations in the inhibited microcosm were lower than dissolved methane originally present in the pore water of the added sediment. Oil samples bailed from four wells in the oil body were analyzed for benzene concentrations and normalized to the benzene content of an archived sample representative of the

  16. Evaluation of bioaerosol sampling techniques for the detection of Chlamydophila psittaci in contaminated air.

    PubMed

    Van Droogenbroeck, Caroline; Van Risseghem, Marleen; Braeckman, Lutgart; Vanrompay, Daisy

    2009-03-16

    Chlamydophila (C.) psittaci, a category B bioterrorism agent, causes respiratory disease in birds and psittacosis or parrot fever in man. The disease spreads aerogenically and no vaccines are available for either birds or man. Highly sensitive C. psittaci bioaerosol monitoring methods are unavailable. We evaluated: (1) dry filtration for collecting C. psittaci from contaminated air using different samplers and membrane filters, (2) impingement into different liquid collection media by use of the AGI-30 impinger and the BioSampler and (3) impaction into newly designed C. psittaci media utilizing the MAS-100 aerosol impactor. For personal bioaerosol sampling, we recommend the use of a gelatin filter in combination with the IOM inhalable dust sampler at an airflow rate of 2L/min. This allowed the detection of 10 organisms of C. psittaci by both PCR and culture. For stationary bioaerosol monitoring, sampling 1000L of air in 10min with the MAS-100 impactor and ChlamyTrap 1 impaction medium was most efficient and made it possible to detect 1 and 10 C. psittaci organisms by PCR and culture, respectively. ChlamyTrap 1 in combination with the MAS-100 impactor might also be applicable for bioaerosol monitoring of viruses.

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

    PubMed

    Bari, Md Aynul; Kindzierski, Warren B

    2017-04-01

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

  18. Changes in blubber contaminant concentrations in California sea lions (Zalophus californianus) associated with weight loss and gain during rehabilitation.

    PubMed

    Hall, A J; Gulland, F M D; Ylitalo, G M; Greig, D J; Lowenstine, L

    2008-06-01

    California sea lions have high levels of persistent organic pollutants (POPs) in their blubber. Animals affected by domoic acid fast and refeed during their rehabilitation. We studied the effect of decreases in total body mass (16 +/- 7% of initial body mass) on blubber POP contaminant concentrations and estimated POP burdens during fasting (12 +/- 5 days) in 19 California sea lions. The effect of refeeding (92 +/- 8% of initial body mass) was also investigated. Significant increases in the concentration of all POPs were found over the mass loss period and decreases during mass gain. A basic mass balance model indicated that the changes did not conform to a simple concentrating and diluting pattern and a proportion of the contaminants were lost from the lipid pool. During mass loss, the lower chlorinated polychlorinated biphenyl congeners, chlordanes, and hexachlorocyclohexanes were lost at a higher rate than the other contaminant classes (particularly polybrominated diphenyl ethers). During mass gain the behavior of all contaminant classes was more consistent with the dilution model. These results indicate the importance of considering the energetic contextwhen sampling blubberfor long-term contaminant monitoring and suggest an initial approach to adjust for such differences.

  19. Status and trends in concentrations of contaminants and measures of biological stress in San Francisco Bay. Technical memo

    SciTech Connect

    Long, E.; MacDonald, D.; Matta, M.B.; VanNess, K.; Buchman, M.

    1988-05-01

    Under the National Status and Trends (NS T) Program, the National Oceanic and Atmospheric Administration (NOAA) monitors the occurrence of certain contaminants and indicators of biological stress at approximately 200 sites in the United States. The Program was initiated in 1984 to provide an internally consistent data base for assessing the condition of parts of the Nation's coastal and estuarine environments. The Program thus far has focused largely upon generation of chemical contaminant data for sediments, fish, and bivalves, and certain analyses of these data. The results of the initial analyses are summarized in progress reports (NOAA, 1987a and b). The objectives of the report are to: (1) portray geographic trends in the concentrations of contaminants and the prevalence of selected measures of biological effects; (2) portray temporal trends in concentrations of contaminants and prevalence of selected measures of biological effects; (3) relate selected measures of biological effects to the concentrations of contaminants; and (4) compare the trends observed in available historical data to compatible recent measurements made by NOAA in San Francisco Bay. These objectives will be met through evaluation of data collected by NOAA and the many others who have studied the conditions in San Fransisco Bay. Some of the data from the NOAA NS T Program will be reported for the first time in the report.

  20. Air mercury contamination in the gold mining town of Portovelo, Ecuador.

    PubMed

    González-Carrasco, Víctor; Velasquez-Lopez, Patricio C; Olivero-Verbel, Jesús; Pájaro-Castro, Nerlis

    2011-09-01

    Portovelo is one of the oldest gold mining towns in Ecuador. Artisanal gold mining still uses mercury in the process of gold recovery. In this study, mercury concentrations in the air of Portovelo were evaluated. High mercury levels in the ambient were found in El Pache sector, where most gold mining processing plants are located. These varied between 2,356.7 ± 1,807.6 and 3,699.5 ± 1,225.3 ng/m(3) during the rainy and dry seasons, respectively. Lower levels were detected in the urban (central) area of Portovelo, with 214.6 ± 43.7 ng/m(3) in the rainy season and 574.2 ± 72.8 ng/m(3) in the dry season, exceeding the Agency for Toxic Substances and Disease Registry minimum risk level of 200 ng/m(3). Average mercury concentrations in exhaled air from miners, measured before and after amalgam burning ranged between 179-1,352 and 2,007-3,389 ng/m(3), respectively. These data suggest Portovelo air is polluted with mercury and humans are being dangerously exposed. Therefore, strong actions must be undertaken to protect human and environmental health, including changing gold recovery systems.

  1. Assessment of air and water contamination by disinfection by-products at 41 indoor swimming pools.

    PubMed

    Tardif, Robert; Catto, Cyril; Haddad, Sami; Simard, Sabrina; Rodriguez, Manuel

    2016-07-01

    This study was aimed at assessing the profiles (occurrence and speciation) of disinfection by-product (DBP) contamination in air and water of a group of 41 public indoor swimming pools in Québec (Canada). The contaminants measured in the water included the traditional DBPs [i.e., four trihalomethanes (THMs), six haloacetic acids (HAAs)] but also several emergent DBPs [i.e., halonitriles, halonitromethanes, haloketones and nitrosodimethylamine (NDMA)]. Those measured in the air comprised THMs and chloramines (CAMs). Overall, extremely variable DBP levels were found from one pool to another (both quantitatively and in terms of speciation). For instance, in water, among the four THMs, chloroform was usually the most abundant compound (37.9±25.7µg/L). Nevertheless, the sum of the three other brominated THMs represented more than 25% of total THMs at almost half the facilities visited (19 cases). In 13 of them, the levels of brominated THMs (66±24.2µg/L) even greatly outweighed the levels of chloroform (15.2±6.31µg/L). Much higher levels of HAAs (294.8±157.6µg/L) were observed, with a consistent preponderance of brominated HAAs in the swimming pools with more brominated THMs. NDMA levels which were measured in a subset of 8 pools ranged between 2.8ng/L and 105ng/L. With respect to air, chloroform was still the most abundant THM globally (119.4±74.2µg/m(3)) but significant levels of brominated THMs were also observed in various cases, particularly in the previously evoked group of 13 swimming pools with preponderant levels of brominated THMs in water. CAM levels (0.23±0.15mg/m(3)) varied highly, ranging from not detected to 0.56mg/m(3). Overall, the levels were generally relatively high compared to current guidelines or reference values from several countries, and they point to a relatively atypical presence of brominated compounds, and to significant levels of emergent DBPs for which health risk is less documented.

  2. Modeling the Concentrations of On-Road Air Pollutants in Southern California

    PubMed Central

    Li, Lianfa; Wu, Jun; Hudda, Neelakshi; Sioutas, Constantinos; Fruin, Scott A.; Delfino, Ralph J.

    2014-01-01

    High concentrations of air pollutants on roadways, relative to ambient concentrations, contribute significantly to total personal exposure. Estimation of these exposures requires measurements or prediction of roadway concentrations. Our study develops, compares and evaluates linear regression and non-linear generalized additive models (GAMs) to estimate on-road concentrations of four key air pollutants, particle-bound polycyclic aromatic hydrocarbons (PB-PAH), particle number count (PNC), nitrogen oxides (NOx), and particulate matter with diameter <2.5 μm (PM2.5) using traffic, meteorology, and elevation variables. Critical predictors included wind speed and direction for all the pollutants, traffic-related variables for PB-PAH, PNC, and NOx, and air temperatures and relative humidity for PM2.5. GAMs explained 50%, 55%, 46%, and 71% of the variance for log or square-root transformed concentrations of PB-PAH, PNC, NOx, and PM2.5 respectively, an improvement of 5 to over 15% over the linear models. Accounting for temporal autocorrelation in the GAMs further improved the prediction, explaining 57-89% of the variance. We concluded that traffic and meteorological data are good predictors in estimating on-road traffic-related air pollutant concentrations and GAMs perform better for non-linear variables, such as meteorological parameters. PMID:23859442

  3. Modelling and analysis of ozone concentration by artificial intelligent techniques for estimating air quality

    NASA Astrophysics Data System (ADS)

    Taylan, Osman

    2017-02-01

    High ozone concentration is an important cause of air pollution mainly due to its role in the greenhouse gas emission. Ozone is produced by photochemical processes which contain nitrogen oxides and volatile organic compounds in the lower atmospheric level. Therefore, monitoring and controlling the quality of air in the urban environment is very important due to the public health care. However, air quality prediction is a highly complex and non-linear process; usually several attributes have to be considered. Artificial intelligent (AI) techniques can be employed to monitor and evaluate the ozone concentration level. The aim of this study is to develop an Adaptive Neuro-Fuzzy inference approach (ANFIS) to determine the influence of peripheral factors on air quality and pollution which is an arising problem due to ozone level in Jeddah city. The concentration of ozone level was considered as a factor to predict the Air Quality (AQ) under the atmospheric conditions. Using Air Quality Standards of Saudi Arabia, ozone concentration level was modelled by employing certain factors such as; nitrogen oxide (NOx), atmospheric pressure, temperature, and relative humidity. Hence, an ANFIS model was developed to observe the ozone concentration level and the model performance was assessed by testing data obtained from the monitoring stations established by the General Authority of Meteorology and Environment Protection of Kingdom of Saudi Arabia. The outcomes of ANFIS model were re-assessed by fuzzy quality charts using quality specification and control limits based on US-EPA air quality standards. The results of present study show that the ANFIS model is a comprehensive approach for the estimation and assessment of ozone level and is a reliable approach to produce more genuine outcomes.

  4. Removal of methanethiol, dimethyl sulfide, dimethyl disulfide, and hydrogen sulfide from contaminated air by Thiobacillus thioparus TK-m

    SciTech Connect

    Kanagawa, T.; Mikami, E.

    1989-03-01

    Methanethiol, dimethyl sulfide, dimethyl disulfide, and hydrogen sulfide were efficiently removed from contaminated air by Thiobacillus thioparus TK-m and oxidized to sulfate stoichiometrically. More than 99.99% of dimethyl sulfide was removed when the load was less than 4.0 g of dimethyl sulfide per g (dry cell weight) per day.

  5. Effect of outside air ventilation rate on VOC concentrations and emissions in a call center

    SciTech Connect

    Hodgson, A.T.; Faulkner, D.; Sullivan, D.P.; DiBartolomeo, D.L.; Russell, M.L.; Fisk, W.J.

    2002-01-01

    A study of the relationship between outside air ventilation rate and concentrations of VOCs generated indoors was conducted in a call center. Ventilation rates were manipulated in the building's four air handling units (AHUs). Concentrations of VOCs in the AHU returns were measured on 7 days during a 13-week period. Indoor minus outdoor concentrations and emission factors were calculated. The emission factor data was subjected to principal component analysis to identify groups of co-varying compounds based on source type. One vector represented emissions of solvents from cleaning products. Another vector identified occupant sources. Direct relationships between ventilation rate and concentrations were not observed for most of the abundant VOCs. This result emphasizes the importance of source control measures for limiting VOC concentrations in buildings.

  6. Effects of the Deregulation on the Concentration of the Brazilian Air Transportation Industry

    NASA Technical Reports Server (NTRS)

    Guterres, Marcelo Xavier; Muller, Carlos

    2003-01-01

    This paper addresses the effects of the deregulation of the Brazilian air transportation industry in terms of the concentration of the market. We will show some metrics that are commonly used to study the concentration of the industry. This paper uses the Herfindhal- Hirschman Index. This index tends to zero in the competitive scenario, with a large number of small firms, and to one in case of a monopolistic scenario. The paper analyses the dynamics of the concentration of the Brazilian domestic air transportation market, in order to evaluate the effects of deregulation. We conclude that the Brazilian market presents oligopoly characteristics and aspects in its current structure that maintain the market concentrated in spite of the Deregulation measures adopted by the aeronautical authority. Keywords: Herfindhal-Hirschman Index, concentration, Deregulation

  7. Influence of indoor air conditions on radon concentration in a detached house.

    PubMed

    Akbari, Keramatollah; Mahmoudi, Jafar; Ghanbari, Mahdi

    2013-02-01

    Radon is released from soil and building materials and can accumulate in residential buildings. Breathing radon and radon progeny for extended periods hazardous to health and can lead to lung cancer. Indoor air conditions and ventilation systems strongly influence indoor radon concentrations. This paper focuses on effects of air change rate, indoor temperature and relative humidity on indoor radon concentrations in a one family detached house in Stockholm, Sweden. In this study a heat recovery ventilation system unit was used to control the ventilation rate and a continuous radon monitor (CRM) was used to measure radon levels. FLUENT, a computational fluid dynamics (CFD) software package was used to simulate radon entry into the building and air change rate, indoor temperature and relative humidity effects using a numerical approach. The results from analytical solution, measurements and numerical simulations showed that air change rate, indoor temperature and moisture had significant effects on indoor radon concentration. Increasing air change rate reduces radon level and for a specific air change rate (in this work Ach = 0.5) there was a range of temperature and relative humidity that minimized radon levels. In this case study minimum radon levels were obtained at temperatures between 20 and 22 °C and a relative humidity of 50-60%.

  8. Estimation of air impacts for bioventing systems used at superfund sites. Air/Superfund National Technical Guidance Study Series

    SciTech Connect

    Dulaney, W.; Eklund, B.; Thompson, C.; Mischler, S.

    1993-04-01

    The report provides procedures for estimating the ambient air concentrations associated with bioventing. Bioventing is an insitu remediation process where oxygen is introduced to the contaminated subsurfaces to enhance biodegradation rates of the organic contaminants. Procedures are given to evaluate the effect of exhaust gas flow rate and contaminant concentration on the emission rates and on the ambient air concentrations at selected distances from the area. Health-based ambient air action levels are also provided for comparison to the estimated ambient concentrations.

  9. Concentrations and patterns of organochlorine contaminants in white whales (Delphinapterus leucas) from Svalbard, Norway.

    PubMed

    Andersen, G; Kovacs, K M; Lydersen, C; Skaare, J U; Gjertz, I; Jenssen, B M

    2001-01-17

    Blubber was collected from live-captured, adult male white whales (Delphinapterus leucas) from Svalbard, Norway, and analysed for levels and patterns of organochlorine (OC) contaminants. The OC compounds analysed were HCB, dieldrin, sigmaHCH (alpha-HCH, beta-HCH and gamma-HCH), sigmaChl (heptachlor epoxide, oxychlordane, cis-chlordane, trans-nonachlor, and cis-nonachlor), sigmaDDT (pp'-DDT, pp'-DDE and pp'-DDD) and sigmaPCB (27 PCB congeners). The major OC compounds detected in the blubber were sigmaPCB (5103+/-1874 ng/g l.w.) and sigmaDDT (5108+/-1089 ng/g l.w.), which made up 70% of the sigmaOC. These compounds were followed in prevalence by sigmaChl (2872+/-1177 ng/g l.w.), which contributed 20% of the sigmaOC burden. SigmaHCH, HCB and dieldrin were present, but at low concentrations. This OC pattern is typical of top predators in Arctic marine food chains. OC levels in white whales from Svalbard are lower than white whales from the St Lawrence River in Canada and are generally similar to values reported previously for other Arctic white whale stocks. Some geographic patterns in relative prevalence of various OC compounds appear to be quite consistent among various marine mammal species in the Arctic. PCB and DDT concentrations in Svalbard's white whales are below the levels that are thought to have negative effects on reproduction or the immune system.

  10. Assessment of concentrations of trace elements in ground water and soil at the Small-Arms Firing Range, Shaw Air Force Base, South Carolina

    USGS Publications Warehouse

    Landmeyer, J.E.

    1994-01-01

    Ground-water samples were collected from four shallow water-table aquifer observation wells beneath the Small-Arms Firing Range study area at Shaw Air Force Base. Water-chemistry analyses indicated that total lead concentrations in shallow ground water beneath the study area do not exceed the U.S. Environmental Protection Agency maximum contaminant level established for lead in drinking water (0.05 milligrams per liter). All other trace element total concentrations in ground water beneath the study area were at or below the detection limit of the analytical methodology.

  11. Estimation of microbial contamination of food from prevalence and concentration data: application to Listeria monocytogenes in fresh vegetables.

    PubMed

    Crépet, Amélie; Albert, Isabelle; Dervin, Catherine; Carlin, Frédéric

    2007-01-01

    A normal distribution and a mixture model of two normal distributions in a Bayesian approach using prevalence and concentration data were used to establish the distribution of contamination of the food-borne pathogenic bacteria Listeria monocytogenes in unprocessed and minimally processed fresh vegetables. A total of 165 prevalence studies, including 15 studies with concentration data, were taken from the scientific literature and from technical reports and used for statistical analysis. The predicted mean of the normal distribution of the logarithms of viable L. monocytogenes per gram of fresh vegetables was -2.63 log viable L. monocytogenes organisms/g, and its standard deviation was 1.48 log viable L. monocytogenes organisms/g. These values were determined by considering one contaminated sample in prevalence studies in which samples are in fact negative. This deliberate overestimation is necessary to complete calculations. With the mixture model, the predicted mean of the distribution of the logarithm of viable L. monocytogenes per gram of fresh vegetables was -3.38 log viable L. monocytogenes organisms/g and its standard deviation was 1.46 log viable L. monocytogenes organisms/g. The probabilities of fresh unprocessed and minimally processed vegetables being contaminated with concentrations higher than 1, 2, and 3 log viable L. monocytogenes organisms/g were 1.44, 0.63, and 0.17%, respectively. Introducing a sensitivity rate of 80 or 95% in the mixture model had a small effect on the estimation of the contamination. In contrast, introducing a low sensitivity rate (40%) resulted in marked differences, especially for high percentiles. There was a significantly lower estimation of contamination in the papers and reports of 2000 to 2005 than in those of 1988 to 1999 and a lower estimation of contamination of leafy salads than that of sprouts and other vegetables. The interest of the mixture model for the estimation of microbial contamination is discussed.

  12. Relationship between acetaldehyde concentration in mouth air and tongue coating volume

    PubMed Central

    YOKOI, Aya; MARUYAMA, Takayuki; YAMANAKA, Reiko; EKUNI, Daisuke; TOMOFUJI, Takaaki; KASHIWAZAKI, Haruhiko; YAMAZAKI, Yutaka; MORITA, Manabu

    2015-01-01

    Objective Acetaldehyde is the first metabolite of ethanol and is produced in the epithelium by mucosal ALDH, while higher levels are derived from microbial oxidation of ethanol by oral microflora such as Candida species. However, it is uncertain whether acetaldehyde concentration in human breath is related to oral condition or local production of acetaldehyde by oral microflora. The aim of this pilot study was to investigate the relationship between physiological acetaldehyde concentration and oral condition in healthy volunteers. Material and Methods Sixty-five volunteers (51 males and 14 females, aged from 20 to 87 years old) participated in the present study. Acetaldehyde concentration in mouth air was measured using a portable monitor. Oral examination, detection of oral Candida species and assessment of alcohol sensitivity were performed. Results Acetaldehyde concentration [median (25%, 75%)] in mouth air was 170.7 (73.5, 306.3) ppb. Acetaldehyde concentration in participants with a tongue coating status score of 3 was significantly higher than in those with a score of 1 (p<0.017). After removing tongue coating, acetaldehyde concentration decreased significantly (p<0.05). Acetaldehyde concentration was not correlated with other clinical parameters, presence of Candida species, smoking status or alcohol sensitivity. Conclusion Physiological acetaldehyde concentration in mouth air was associated with tongue coating volume. PMID:25760268

  13. Measured phenol concentrations in air and rain water samples collected near a wood preserving facility

    SciTech Connect

    Allen, S.K.; Allen, C.W.

    1995-12-31

    Phenol concentrations were determined in air and rain water samples collected downwind from a coal tar creosote wood preserving facility in Terre Haute, IN. Coal tar creosote is known to contain a large number of constituents and is composed chiefly of polycyclic aromatic hydrocarbons (PAH), phenols, and N-, S-, and O-heterocycles. Phenol was chosen as a marker compound for coal tar creosote emissions because it is present at a large mole fraction in coal tar creosote. Phenol was determined by HPLC with UV-Visible detection. Phenol in collected rain water samples was determined directly by HPLC after acidification and filtration. Phenol concentrations in collected air samples ranged from 4.1 to 15.7 {micro}g/m3 while rain water concentrations ranged from 7.9 to 28.2 {micro}g/L. Using a value for the thermodynamic Henry`s law constant of K{sub H} = 4.5 {times} 10{sup {minus}4} L atm/mole at 20 C for phenol and measured gas-phase phenol concentrations, even higher rain water concentrations would be expected if equilibrium was established. This indicates that the amount of phenol present in the air parcels sampled exceeded the amount that could be scavenged by rain drops under the conditions prevailing at the time of sampling. The values for phenol concentrations reported here are roughly two orders of magnitude higher than results from previous studies where phenol concentrations in air and rain water samples collected in urban areas were reported. It is likely that other more toxic constituents of coal tar creosote are also present at high concentrations in air parcels that receive emissions from wood treatment facilities.

  14. Lead-210 concentration in the air at Mt. Zeppelin, Ny-Ålesund, Svalbard

    NASA Astrophysics Data System (ADS)

    Paatero, Jussi; Hatakka, Juha; Holmén, Kim; Eneroth, Kristina; Viisanen, Yrjö

    High-volume aerosol particle samples have been collected onto glass fibre filters at Ny-Ålesund, Svalbard. The filters have been assayed for 210Pb by measuring the alpha particles of its in-grown daughter nuclide 210Po. The observed 210Pb activity concentrations at Mt. Zeppelin, Ny-Ålesund, Svalbard vary between 11 and 620 μBq/m 3 in 2001. The 25%, 50%, and 75% percentiles of the 210Pb activity concentrations at Mt. Zeppelin are 42, 83, and 220 μBq/m 3. The values are clearly lower than at Sodankylä, northern Finland with corresponding values of 100, 170, and 270 μBq/m 3. The arithmetic mean concentrations in 2001 were 144 and 245 μBq/m 3 at Ny-Ålesund and Sodankylä, respectively. The lowest 210Pb activity concentrations are found during summer both at Svalbard and in Finland. The highest concentrations occur in March-April at Svalbard. This differs from the seasonal behaviour of 210Pb in Finland, where the highest concentrations are usually observed in February-March. This 1-month difference between Svalbard and Finland may be related to the strength of solar radiation and its capability to cause vertical mixing of the air. Air mass back trajectory analysis shows that the lowest concentrations found at Svalbard are associated with air masses coming from the North Atlantic Ocean, Greenland and the Canadian Arctic. The highest concentrations are associated with air masses originating from northern Europe and Siberia, and during winter also in air masses coming from the central Arctic Ocean.

  15. Estimate of uptake and translocation of emerging organic contaminants from irrigation water concentration in lettuce grown under controlled conditions.

    PubMed

    Hurtado, Carlos; Domínguez, Carmen; Pérez-Babace, Lorea; Cañameras, Núria; Comas, Jordi; Bayona, Josep M

    2016-03-15

    The widespread distribution of emerging organic contaminants (EOCs) in the water cycle can lead to their incorporation in irrigated crops, posing a potential risk for human consumption. To gain further insight into the processes controlling the uptake of organic microcontaminants, Batavia lettuce (Lactuca sativa) grown under controlled conditions was watered with EOCs (e.g., non-steroidal anti-inflammatories, sulfonamides, β-blockers, phenolic estrogens, anticonvulsants, stimulants, polycyclic musks, biocides) at different concentrations (0-40μgL(-1)). Linear correlations were obtained between the EOC concentrations in the roots and leaves and the watering concentrations for most of the contaminants investigated. However, large differences were found in the root concentration factors ( [Formula: see text] =0.27-733) and leaf translocation concentration factors ( [Formula: see text] =0-3) depending on the persistence of the target contaminants in the rhizosphere and the specific physicochemical properties of each one. With the obtained dataset, a simple predictive model based on a linear regression and the root bioconcentration and translocation factors can be used to estimate the concentration of the target EOCs in leaves based on the dose supplied in the irrigation water or the soil concentration. Finally, enantiomeric fractionation of racemic ibuprofen from the initial spiking mixture suggests that biodegradation mainly occurs in the rhizosphere.

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

    USGS Publications Warehouse

    Harte, Philip T.

    2015-01-01

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

  17. Hot air injection for removal of dense, non-aqueous-phase liquid contaminants from low-permeability soils

    SciTech Connect

    Payne, F.C.

    1996-08-01

    The performance of soil vapor extraction systems for the recovery of volatile and semi-volatile organic compounds is potentially enhanced by the injection of heated air to increase soil temperatures. The soil temperature increase is expected to improve soil vapor extraction (SVE) performance by increasing target compound vapor pressures and by increasing soil permeability through drying. The vapor pressure increase due to temperature rise relieves the vapor pressure limit on the feasibility of soil vapor extraction. However, the system still requires an air flow through the soil system to deliver heat and to recover mobilized contaminants. Although the soil permeability can be increased through drying, very low permeability soils and low permeability soils adjacent to high permeability air flow pathways will be treated slowly, if at all. AR thermal enhancement methods face this limitation. Heated air injection offers advantages relative to other thermal techniques, including low capital and operation costs. Heated air injection is at a disadvantage relative to other thermal techniques due to the low heat capacity of air. To be effective, heated air injection requires that higher air flows be established than for steam injection or radio frequency heating. Heated air injection is not economically feasible for the stratified soil system developed as a standard test for this document. This is due to the inability to restrict heated air flow to the clay stratum when a low-resistance air flow pathway is available in the adjoining sand. However, the technology should be especially attractive, both technically and economically, for low-volatile contaminant recovery from relatively homogeneous soil formations. 16 refs., 2 tabs.

  18. Associations between Organochlorine Contaminant Concentrations and Clinical Health Parameters in Loggerhead Sea Turtles from North Carolina, USA

    PubMed Central

    Keller, Jennifer M.; Kucklick, John R.; Stamper, M. Andrew; Harms, Craig A.; McClellan-Green, Patricia D.

    2004-01-01

    Widespread and persistent organochlorine (OC) contaminants, such as polychlorinated biphenyls (PCBs) and pesticides, are known to have broad-ranging toxicities in wildlife. In this study we investigated, for the first time, their possible health effects on loggerhead sea turtles (Caretta caretta). Nonlethal fat biopsies and blood samples were collected from live turtles for OC contaminant analysis, and concentrations were compared with clinical health assessment data, including hematology, plasma chemistry, and body condition. Concentrations of total PCBs (∑PCBs), ∑DDTs, ∑chlordanes, dieldrin, and mirex were determined in 44 fat biopsies and 48 blood samples. Blood concentrations of ∑chlordanes were negatively correlated with red blood cell counts, hemoglobin, and hematocrit, indicative of anemia. Positive correlations were observed between most classes of OC contaminants and white blood cell counts and between mirex and ∑TCDD-like PCB concentrations and the heterophil:lymphocyte ratio, suggesting modulation of the immune system. All classes of OCs in the blood except dieldrin were correlated positively with aspartate aminotransferase (AST) activity, indicating possible hepatocellular damage. Mirex and ∑TCDD-like PCB blood concentrations were negatively correlated with alkaline phosphatase (ALP) activity. Significant correlations to levels of certain OC contaminant classes also suggested possible alteration of protein (↑blood urea nitrogen, ↓albumin:globulin ratio), carbohydrate (↓glucose), and ion (↑sodium, ↓magnesium) regulation. These correlations suggest that OC contaminants may be affecting the health of loggerhead sea turtles even though sea turtles accumulate lower concentrations of OCs compared with other wildlife. PMID:15238280

  19. Mitigating factors on air concentrations of radon emanating from different granite samples

    SciTech Connect

    Qari, T.M.; Mamoon, A.M.; Abdul-Fattah, A.F. )

    1991-11-01

    Continuous exposure to increased air concentrations of radon in living areas is to be avoided according to the Environmental Protection Agency (EPA) and several published reports. Radon concentrations in ambient air are influenced by several factors related to the nature of the radon source itself, environmental conditions, and the presence of mitigating factors, if any. In this study, crushed granite samples of different types, particle diameters, and moisture contents were compared in simplified test systems with regard to radon emanation from the samples. The effects of selected mitigating factors, namely, ventilation and different barriers to diffusion of emanated radon were determined.

  20. High Concentrations of Ozone Air Pollution on Mount Everest: Health Implications for Sherpa Communities and Mountaineers.

    PubMed

    Semple, John L; Moore, G W Kent; Koutrakis, Petros; Wolfson, Jack M; Cristofanelli, Paolo; Bonasoni, Paolo

    2016-12-01

    Semple, John L., G.W. Kent Moore, Petros Koutrakis, Jack M. Wolfson, Paolo Cristofanelli, and Paolo Bonasoni. High concentrations of ozone air pollution on Mount Everest: health implications for Sherpa communities and mountaineers. High Alt Med Biol. 17:365-369, 2016.-Introduction: Populations in remote mountain regions are increasingly vulnerable to multiple climate mechanisms that influence levels of air pollution. Few studies have reported on climate-sensitive health outcomes unique to high altitude ecosystems. In this study, we report on the discovery of high-surface ozone concentrations and the potential impact on health outcomes on Mount Everest and the high Himalaya.

  1. Evaluation of Background Concentrations of Contaminants in an Unusual Desert Arroyo Near a Uranium Mill Tailings Disposal Cell - 12260

    SciTech Connect

    Bush, Richard P.; Morrison, Stan J.

    2012-07-01

    The U.S. Department of Energy (DOE) Office of Legacy Management (LM) manages 27 sites that have groundwater containing uranium concentrations above background levels. The distal portions of the plumes merge into background groundwater that can have 50 μg/L or more uranium. Distinguishing background from site-related uranium is often problematic, but it is critical to determining if remediation is warranted, establishing appropriate remediation goals, and evaluating disposal cell performance. In particular, groundwater at disposal cells located on the upper Cretaceous Mancos Shale may have relatively high background concentrations of uranium. Elevated concentrations of nitrate, selenium, and sulfate accompany the uranium. LM used geologic analogs and uranium isotopic signatures to distinguish background groundwater from groundwater contaminated by a former uranium processing site. The same suite of contaminants is present in groundwater near former uranium processing sites and in groundwater seeps emanating from the Mancos Shale over a broad area. The concentrations of these contaminants in Many Devils Wash, located near LM's Shiprock disposal cell, are similar to those in samples collected from many Mancos seeps, including two analog sites that are 8 to 11 km from the disposal cell. Samples collected from Many Devils Wash and the analog sites have high AR values (about 2.0)-in contrast, groundwater samples collected near the tailings disposal cell have AR values near 1.0. These chemical signatures raise questions about the origin of the contamination seeping into Many Devils Wash. (authors)

  2. Effects of dissolved organic matter from a eutrophic lake on the freely dissolved concentrations of emerging organic contaminants.

    PubMed

    Xiao, Yi-Hua; Huang, Qing-Hui; Vähätalo, Anssi V; Li, Fei-Peng; Chen, Ling

    2014-08-01

    The authors studied the effects of dissolved organic matter (DOM) on the bioavailability of bisphenol A (BPA) and chloramphenicol by measuring the freely dissolved concentrations of the contaminants in solutions containing DOM that had been isolated from a mesocosm in a eutrophic lake. The abundance and aromaticity of the chromophoric DOM increased over the 25-d mesocosm experiment. The BPA freely dissolved concentration was 72.3% lower and the chloramphenicol freely dissolved concentration was 56.2% lower using DOM collected on day 25 than using DOM collected on day 1 of the mesocosm experiment. The freely dissolved concentrations negatively correlated with the ultraviolent absorption coefficient at 254 nm and positively correlated with the spectral slope of chromophoric DOM, suggesting that the bioavailability of these emerging organic contaminants depends on the characteristics of the DOM present. The DOM-water partition coefficients (log KOC ) for the emerging organic contaminants positively correlated with the aromaticity of the DOM, measured as humic acid-like fluorescent components C1 (excitation/emission=250[313]/412 nm) and C2 (excitation/emission=268[379]/456 nm). The authors conclude that the bioavailability of emerging organic contaminants in eutrophic lakes can be affected by changes in the DOM.

  3. Concentration and removal of tritium and/or deuterium from water contaminated with tritium and/or deuterium

    SciTech Connect

    Meyer, Thomas J.; Narula, Poonam M.

    2001-01-01

    Concentration of tritium and/or deuterium that is a contaminant in H.sub.2 O, followed by separation of the concentrate from the H.sub.2 O. Employed are certain metal oxo complexes, preferably with a metal from Group VIII. For instance, [Ru.sup.IV (2,2',6',2"-terpyridine)(2,2'-bipyridine)(O)](ClO.sub.4).sub.2 is very suitable.

  4. Sensory and chemical characterization of VOC emissions from building products: impact of concentration and air velocity

    NASA Astrophysics Data System (ADS)

    Knudsen, H. N.; Kjaer, U. D.; Nielsen, P. A.; Wolkoff, P.

    The emissions from five commonly used building products were studied in small-scale test chambers over a period of 50 days. The odor intensity was assessed by a sensory panel and the concentrations of selected volatile organic compounds (VOCs) of concern for the indoor air quality were measured. The building products were three floor coverings: PVC, floor varnish on beechwood parquet and nylon carpet on a latex foam backing; an acrylic sealant, and a waterborne wall paint on gypsum board. The impacts of the VOC concentration in the air and the air velocity over the building products on the odor intensity and on the emission rate of VOCs were studied. The emission from each building product was studied under two or three different area-specific ventilation rates, i.e. different ratios of ventilation rate of the test chamber and building product area in the test chamber. The air velocity over the building product samples was adjusted to different levels between 0.1 and 0.3 m s -1. The origin of the emitted VOCs was assessed in order to distinguish between primary and secondary emissions. The results show that it is reasonable after an initial period of up to 14 days to consider the emission rate of VOCs of primary origin from most building products as being independent of the concentration and of the air velocity. However, if the building product surface is sensitive to oxidative degradation, increased air velocity may result in increased secondary emissions. The odor intensity of the emissions from the building products only decayed modestly over time. Consequently, it is recommended to use building products which have a low impact on the perceived air quality from the moment they are applied. The odor indices (i.e. concentration divided by odor threshold) of primary VOCs decayed markedly faster than the corresponding odor intensities. This indicates that the secondary emissions rather than the primary emissions, are likely to affect the perceived air quality in the

  5. Preliminary assessment of BTEX concentrations in indoor air of residential buildings and atmospheric ambient air in Ardabil, Iran

    NASA Astrophysics Data System (ADS)

    Hazrati, Sadegh; Rostami, Roohollah; Farjaminezhad, Manoochehr; Fazlzadeh, Mehdi

    2016-05-01

    BTEX concentrations in indoor and outdoor air of 50 homes were studied in Ardabil city and their influencing parameters including; heating system, using gas stove and samovar, tobacco smoking, the floors in which the monitored homes were located, and kitchen plan were considered in the study. Risk assessment analysis was carried out with the obtained concentrations based on EPA IRIS reference doses. BTEX compounds were sampled by charcoal tubes and the samples were analyzed by a GC-FID. Concentrations of benzene (15.18 μg/m3 vs. 8.65 μg/m3), toluene (69.70 μg/m3 vs. 40.56 μg/m3), ethylbenzene (12.07 μg/m3 vs. 4.92 μg/m3) and xylene (48.08 μg/m3 vs. 7.44 μg/m3) in indoor air were significantly (p < 0.05) higher than the levels quantified for outdoor air. The obtained concentrations of benzene were considerably higher than the recommended value of 5 μg/m3 established by Iran environmental protection organization. Among the BTEX compounds, benzene (HQ = 0.51) and xylene (HQ = 0.47) had notable hazard quotient and were the main pollutants responsible for high hazard index in the monitored homes (HI = 1.003). The results showed considerably high cancer risk for lifetime exposure to the indoor (125 × 10-6) and outdoor (71 × 10-6) benzene. Indoor benzene concentrations in homes were significantly influenced by type of heating system, story, and natural gas appliances.

  6. Contamination in Fractured-Rock Aquifers - Research at the former Naval Air Warfare Center, West Trenton, New Jersey

    USGS Publications Warehouse

    Goode, Daniel J.; Tiedeman, Claire R.; Lacombe, Pierre J.; Imbrigiotta, Thomas E.; Shapiro, Allen M.; Chapelle, Francis H.

    2007-01-01

    The U.S. Geological Survey and cooperators are studying chlorinated solvents in a fractured sedimentary rock aquifer underlying the former Naval Air Warfare Center (NAWC), West Trenton, New Jersey. Fractured-rock aquifers are common in many parts of the United States and are highly susceptible to contamination, particularly at industrial sites. Compared to 'unconsolidated' aquifers, there can be much more uncertainty about the direction and rate of contaminant migration and about the processes and factors that control chemical and microbial transformations of contaminants. Research at the NAWC is improving understanding of the transport and fate of chlorinated solvents in fractured-rock aquifers and will compare the effectiveness of different strategies for contaminant remediation.

  7. Equilibrium Partitioning Approach for Assessing Toxicity of Contaminants in Sediments: Linking Measured Concentrations to Effects

    EPA Science Inventory

    A variety of approaches exist for assessing the degree, extent and/or risk of metals contamination in sediments. Selection of the “correct” approach depends on the nature of the question being asked (e.g., the degree of metals contamination in marine sediments may be estimated by...

  8. [Estimation of average traffic emission factor based on synchronized incremental traffic flow and air pollutant concentration].

    PubMed

    Li, Run-Kui; Zhao, Tong; Li, Zhi-Peng; Ding, Wen-Jun; Cui, Xiao-Yong; Xu, Qun; Song, Xian-Feng

    2014-04-01

    On-road vehicle emissions have become the main source of urban air pollution and attracted broad attentions. Vehicle emission factor is a basic parameter to reflect the status of vehicle emissions, but the measured emission factor is difficult to obtain, and the simulated emission factor is not localized in China. Based on the synchronized increments of traffic flow and concentration of air pollutants in the morning rush hour period, while meteorological condition and background air pollution concentration retain relatively stable, the relationship between the increase of traffic and the increase of air pollution concentration close to a road is established. Infinite line source Gaussian dispersion model was transformed for the inversion of average vehicle emission factors. A case study was conducted on a main road in Beijing. Traffic flow, meteorological data and carbon monoxide (CO) concentration were collected to estimate average vehicle emission factors of CO. The results were compared with simulated emission factors of COPERT4 model. Results showed that the average emission factors estimated by the proposed approach and COPERT4 in August were 2.0 g x km(-1) and 1.2 g x km(-1), respectively, and in December were 5.5 g x km(-1) and 5.2 g x km(-1), respectively. The emission factors from the proposed approach and COPERT4 showed close values and similar seasonal trends. The proposed method for average emission factor estimation eliminates the disturbance of background concentrations and potentially provides real-time access to vehicle fleet emission factors.

  9. Comparison of mold concentrations quantified by MSQPCR in indoor and outdoor air sampled simultaneously

    SciTech Connect

    Meklin, Teija; Reponen, Tina; McKinstry, Craig A.; Cho, Seung H.; Grinshpun, Sergey A.; Nevalainen, Aino; Vepsalainen, Asko; Haugland, Richard A.; Lemasters, Grace; Vesper, Sephen J.

    2007-08-15

    Mold specific quantitative PCR (MSQPCR) was used to measure the concentrations of 36 mold species in dust and in indoor and in outdoor air samples that were taken simultaneously in 17 homes in Cincinnati with no-known water damage. The total spore concentrations in the indoor (I) and outdoor (O) air samples were statistically significantly different and the concentrations in the three sample types of many of the individual species were significantly different (p < 0.05 based on the Wilcoxon Signed Rank Test). The I/O ratios of the averages or geometric means of the individual species were generally less than 1; but these I/O ratios were quite variable ranging from 0.03 for A. sydowii to 1.2 for Acremonium strictum. There were no significant correlations for the 36 specific mold concentrations between the dust samples and the indoor or outdoor air samples (based on the Spearman’s Rho test). The indoor and outdoor air concentrations of 32 of the species were not correlated. Only Aspergillus penicillioides, C. cladosporioides types 1 and 2 and C. herbarum had sufficient data to estimate a correlation at rho > 0.5 with signicance (p < 0.05) In six of these homes, a previous dust sample had been collected and analyzed 2 years earlier. The ERMI© values for the dust samples taken in the same home two years apart were not significantly different (p=0.22) based on Wilcoxon Signed Rank Test.

  10. [Spatiotemporal distribution of negative air ion concentration in urban area and related affecting factors: a review].

    PubMed

    Huang, Xiang-Hua; Wang, Jian; Zeng, Hong-Da; Chen, Guang-Shui; Zhong, Xian-Fang

    2013-06-01

    Negative air ion (NAI) concentration is an important indicator comprehensively reflecting air quality, and has significance to human beings living environment. This paper summarized the spatiotemporal distribution features of urban NAI concentration, and discussed the causes of these features based on the characteristics of the environmental factors in urban area and their effects on the physical and chemical processes of NAI. The temporal distribution of NAI concentration is mainly controlled by the periodic variation of solar radiation, while the spatial distribution of NAI concentration along the urban-rural gradient is mainly affected by the urban aerosol distribution, underlying surface characters, and urban heat island effect. The high NAI concentration in urban green area is related to the vegetation life activities and soil radiation, while the higher NAI concentration near the water environment is attributed to the water molecules that participate in the generation of NAI through a variety of ways. The other environmental factors can also affect the generation, life span, component, translocation, and distribution of NAI to some extent. To increase the urban green space and atmospheric humidity and to maintain the soil natural attributes of underlying surface could be the effective ways to increase the urban NAI concentration and improve the urban air quality.

  11. Radon daughters' concentration in air and exposure of joggers at the university campus of Bangalore, India.

    PubMed

    Ashok, G V; Nagaiah, N; Shiva Prasad, N G

    2008-09-01

    The concentration of radon daughters in outdoor air was measured continuously from January 2006 to December 2006 near the Department of Physics, Bangalore University campus, Bangalore. The concentration was measured by collecting air samples at a height of 1 m above the ground level on a glass micro fibre filter paper with a known air flow rate. The results show that the radon progeny concentration exhibits distinct seasonal and diurnal variations that are predominantly caused by changes in the temperature gradient at the soil-atmosphere interface. The concentration was found to be high from 20.00 to 8.00 hrs, when the turbulence mixing was minimum and low during the rest of the time. In terms of the monthly concentration, January was found to be the highest with September/August being the lowest. The diurnal variations in the concentrations of radon progeny were found to exhibit positive correlation with the relative humidity and anti-correlation with the atmospheric temperature. From the measured concentration, an attempt was made to establish the annual effective dose to the general public of the region and was found to be 0.085 mSv/a. In addition, an attempt was also made for the first time to study the variation of inhalation dose with respect to the physical activity levels. Results show that in the light of both the effect of chemical pollutants and radiation dose due to inhalation of radon daughters, evening jogging is advisable.

  12. Spatial and Temporal Variability in Nitrate Concentration below the Root Zone in an Almond Orchard and its Implications for Potential Groundwater Contamination

    NASA Astrophysics Data System (ADS)

    Baram, S.; Couvreur, V.

    2015-12-01

    Spatial and Temporal Variability in Nitrate Concentration below the Root Zone in an Almond Orchard and its Implications for Potential Groundwater Contamination S. Baram1, M. Read1, D. Smart2, T. Harter1, J Hopmans11Department of Land, Air & Water Resources University of California Davis 2Department of Viticulture and Enology University of California Davis Estimates of water and fertilizer losses below the root zone of nitrogen (N) intensive agricultural orchard crops are major concern in groundwater protection. However, microscopic and macroscopic heterogeneity in unsaturated soils make accurate loss estimates very challenging. In this study we aimed to examine field scale variability in nitrate (NO3-) losses below the root zone (>250cm) of a 15 years old almond orchard in Madera county California. Based on a soil variability survey, tensiometers and solution samplers were installed at 17 locations around the 40 acre orchard. The hydraulic potential and the NO3- concentrations were monitored over two growing seasons. Nitrate concentrations varied spatially and temporarily, and ranged from below to more than 30 times higher than the drinking water contamination standard of >10 mg NO3--N L-1. Principal component analysis of the relations between the NO3- concentration, presence of a hard pan in the subsurface, its depth and thickness, and the fertigation and irrigation events indicated that none of these factors explained the observed variability in pore-water NO3- concentrations, with hard pan being the most dominant factor. Throughout the irrigation season minimal leaching was observed, yet post-harvest and preseason flooding events led to deep drainage. Due to the high spatial and temporal variability in the NO3- concentration and the potential for deep drainage following a wet winter or flooding event we conclude that the most efficient way to protect ground water is by transitioning to high frequency low nitrogen fertigation which would retain NO3-in the active

  13. Assessment of contamination based on trace element concentrations in Gomphus flavipes (Odonata: Insect) larvae of the Upper Tisza Region.

    PubMed

    Simon, E; Kis, O; Jakab, T; Kolozsvári, I; Málnás, K; Harangi, S; Baranyai, E; Miskolczi, M; Tóthmérész, B; Dévai, Gy

    2017-02-01

    Odonata larvae are frequently used to assess the contamination of aquatic systems, because they tolerate a wide range of chemical and biological conditions in freshwater systems. In early 2000, the sediments of the Hungarian section of the River Tisza and the River Szamos were strongly enriched with heavy metals by an accidental mining spill. Earlier studies demonstrated higher contamination levels in the Szamos than in the Tisza, based on sediment analysis. The aim of our study was to assess the contamination in the Upper Tisza Region, along the upper reach of the Tisza, and the lower reach of the Szamos, based on the trace element concentrations of the Gomphus flavipes larvae. We collected 269 dragonfly specimens for the analyses. The Al, Ba, Cr, Cu, Fe, Mn, Pb, Sr and Zn element contents were analysed in the dragonfly larvae by microwave plasma atomic emission spectrometry (MP-AES). Significantly higher Ba and Cu concentrations were found in the dragonfly larvae of the Tisza than the Szamos. In spite of this, the Cr, Mn, Pb, Sr and Zn concentration was significantly lower in the dragonfly larvae of the Tisza than the Szamos. For all trace elements significant differences were found along the Tisza. Significant differences were also found in all trace element concentrations of dragonfly larvae among studied localities in the Szamos, except in the cases of Al and Ba. Our results demonstrated that the Szamos was more contaminated with Cr, Mn, Pb, Sr and Zn than the Tisza, but that the Tisza was more contaminated with Ba and Cu than the Szamos, based on the trace element concentrations in Gomphus flavipes larvae, which was likely to have been caused by the tributaries of the Tisza. In summary, our results indicated a continuous pollution of the Tisza and the Szamos and their tributaries.

  14. Rapid air titration method for determining SO/sub 2/ concentration in inhalation chambers

    SciTech Connect

    Snyder, E.A.; Palmes, E.D.

    1985-06-01

    A rapid air titration method for determining SO/sub 2/ concentration in inhalation chambers has been validated using the pararosaniline-formaldehyde (PRA) method of West and Gaeke. This air-titration (iodate) method is an adaptation of iodometric methods using a starch indicator. Potassium iodate and an excess of potassium iodide are used in the reaction. Sampling is completed in ten minutes or less and concentration is calculated by use of a simple formula. Linear equations were derived over the range of concentrations from 0.5 to 100 ppm SO/sub 2/ for uncorrected iodate bubbler results, data corrected for tandem bubbler concentrations and data corrected for mean iodate bubbler efficiency. Linear correlation with the PRA method over this range was 0.999 for all three sets of data.

  15. Comparison of vapor concentrations of volatile organic compounds with ground-water concentrations of selected contaminants in sediments beneath the Sudbury River, Ashland, Massachusetts, 2000

    USGS Publications Warehouse

    Campbell, J.P.; Lyford, F.P.; Willey, Richard E.

    2002-01-01

    A mixed plume of contaminants in ground water, including volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), and metals, near the former Nyanza property in Ashland, Massachusetts, discharges to the Sudbury River upstream and downstream of Mill Pond and a former mill raceway. Polyethylene-membrane vapor-diffusion (PVD) samplers were installed in river-bottom sediments to determine if PVD samplers provide an alternative to ground-water sampling from well points for identifying areas of detectable concentrations of contaminants in sediment pore water near the ground-water and surface-water interface. In August and September 2000, the PVD samplers were installed near well points at depths of 8 to 12 inches in both fine and coarse sediments, whereas the well points were installed at depths of 1 to 5 feet in coarse sediments only. Comparison between vapor and water samples at 29 locations upstream from Mill Pond show that VOC vapor concentrations from PVD samplers in coarse river-bottom sediments are more likely to correspond to ground-water concentrations from well points than PVD samplers installed in fine sediments. Significant correlations based on Kendall's Tau were shown between vapor and ground-water concentrations for trichloroethylene and chlorobenzene for PVD samplers installed in coarse sediments where the fine organic layer that separated the two sampling depths was 1 foot or less in thickness. VOC concentrations from vapor samples also were compared to VOC, SVOC, and metals concentrations from ground-water samples at 10 well points installed upstream and downstream from Mill Pond, and in the former mill raceway. Chlorobenzene vapor concentrations correlated significantly with ground-water concentrations for 5 VOCs, 2 SVOCs, and 10 metals. Trichloroethylene vapor concentrations did not correlate with any of the other ground-water constituents analyzed at the 10 well points. Chlorobenzene detected by use of PVD samplers appears to be a

  16. Metabolite to parent drug concentration ratios in hair for the differentiation of tramadol intake from external contamination and passive exposure.

    PubMed

    Madry, Milena M; Rust, Kristina Y; Guglielmello, Rosetta; Baumgartner, Markus R; Kraemer, Thomas

    2012-11-30

    Tramadol was found in a man's hair sample during an abstinence test necessary to regain his driving license. The suspect denied having taken tramadol claiming external contamination as the reason for the positive result, as he was working in a tramadol production company. Nevertheless, low concentrations of both major metabolites, N-desmethyltramadol (NDMT) and O-desmethyltramadol (ODMT), were found in hair (180 and 6 pg/mg hair, respectively). To assess this case, tramadol concentrations and metabolite to parent drug concentration ratios were determined in hair samples of 75 patients taking tramadol and of eight employees working in the production and laboratory site of the same company. Additionally, wash water used for decontaminating hair was analyzed for both groups, patients and employees. Analysis of hair sample extracts was performed by LC-MS/MS using multiple reaction monitoring (MRM), information dependent acquisition (IDA) and enhanced product ion scan (EPI). High variations of metabolite to parent drug concentration ratios in hair samples of patients were observed. Differences in NDMT and ODMT to tramadol concentration ratios were found when comparing the cohort of patients to employees. The suspect could be included in the cohort of employees considering the ODMT to tramadol concentration ratio in hair and tramadol concentration ratio in wash water versus hair. Metabolite to parent drug concentration ratios of hair samples may represent a helpful tool for the differentiation of tramadol intake versus external contamination. Ratios of tramadol concentrations in wash water versus the subjects' hair may provide additional information for case assessments.

  17. Ambient air concentrations of PCDDs, PCDFs, coplanar PCBs, and PAHs at the Mississippi Sandhill Crane National Wildlife Refuge, Jackson County, Mississippi

    USGS Publications Warehouse

    White, D.H.; Hardy, J.W.

    1994-01-01

    Our objective was to determine the levels of selected airborne contaminants in ambient air at the Mississippi Sandhill Crane National Wildlife Refuge, Mississippi, that might be affecting the health of endangered cranes living there. Two high-volume air samplers were operated at separate locations on the Refuge during May?September 1991. The sampling media were micro-quartz filters in combination with polyurethane foam plugs. Composite bimonthly samples from each station were analyzed for polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), coplanar polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs). Overall, residue concentrations were low. The toxic PCDD isomer 2,3,7,8-tetra-CDD was not detected, nor was penta-CDD. There was no difference (P>0.05) in residue concentrations between stations or over time and meteorological parameters were not correlated with residue concentrations. Because contaminant levels and patterns may differ seasonally, we recommend that air samples collected during winter months also be analyzed for these same chemical groups.

  18. Procedures for addressing uncertainty and variability in exposure to characterize potential health risk from trichloroethylene contaminated groundwater at Beale Air Force Base in California

    SciTech Connect

    Bogen, K T; Daniels, J I; Hall, L C

    1999-09-01

    This study was designed to accomplish two objectives. The first was to provide to the US Air Force and the regulatory community quantitative procedures that they might want to consider using for addressing uncertainty and variability in exposure to better characterize potential health risk. Such methods could be used at sites where populations may now or in the future be faced with using groundwater contaminated with low concentrations of the chemical trichloroethylene (TCE). The second was to illustrate and explain the application of these procedures with respect to available data for TCE in ground water beneath an inactive landfill site that is undergoing remediation at Beale Air Force Base in California. The results from this illustration provide more detail than the more traditional conservative deterministic, screening-level calculations of risk, also computed for purposes of comparison. Application of the procedures described in this report can lead to more reasonable and equitable risk-acceptability criteria for potentially exposed populations at specific sites.

  19. A Comparison of Statistical Techniques for Combining Modeled and Observed Concentrations to Create High-Resolution Ozone Air Quality Surfaces

    EPA Science Inventory

    Air quality surfaces representing pollutant concentrations across space and time are needed for many applications, including tracking trends and relating air quality to human and ecosystem health. The spatial and temporal characteristics of these surfaces may reveal new informat...

  20. Application of hybrid coagulation microfiltration with air backflushing to direct sewage concentration for organic matter recovery.

    PubMed

    Jin, Zhengyu; Gong, Hui; Wang, Kaijun

    2015-01-01

    The idea of sewage concentration is gradually being accepted as a promising and sustainable way of wastewater resource recovery. In this study, Hybrid coagulation microfiltration (HCM) with air backflushing (AB) was investigated to effectively concentrate organic matter. Compared to direct sewage microfiltration, the addition of coagulation process improved the filtration performance with less fouling trends and better concentration efficiency. The use of AB exhibited even better performance within the same 7-h preliminary concentration period by reducing to one tenth of the resistance and collecting around four times as much organic matter into the product concentrate as in direct sewage microfiltration. During 93-h lab-scale continuous concentration by HCM with AB, a product concentrate with the COD concentration over 15,000 mg/L was achieved and around 70% of total influent organic matter could be recovered. Compared to Direct Membrane Filtration (DMF) with Chemically Enhanced Backwash (CEB), HCM with AB achieved better concentration efficiency with higher concentration extent and concentration velocity along with less organic matter mineralization and the more concentrated product despite with lower organic matter retention. HCM with AB could be a promising effective sewage organic matter concentration for resource recovery under optimization.

  1. Microlith-Based Catalytic Reactor for Air Quality and Trace Contaminant Control Applications

    NASA Technical Reports Server (NTRS)

    Vilekar, Saurabh; Hawley, Kyle; Junaedi, Christian; Crowder, Bruce; Prada, Julian; Mastanduno, Richard; Perry, Jay L.; Kayatin, Matthew J.

    2015-01-01

    Traditionally, gaseous compounds such as methane, carbon monoxide, and trace contaminants have posed challenges for maintaining clean air in enclosed spaces such as crewed spacecraft cabins as they are hazardous to humans and are often difficult to remove by conventional adsorption technology. Catalytic oxidizers have provided a reliable and robust means of disposing of even trace levels of these compounds by converting them into carbon dioxide and water. Precision Combustion, Inc. (PCI) and NASA - Marshall (MSFC) have been developing, characterizing, and optimizing high temperature catalytic oxidizers (HTCO) based on PCI's patented Microlith® technology to meet the requirements of future extended human spaceflight explorations. Current efforts have focused on integrating the HTCO unit with a compact, simple recuperative heat exchanger to reduce the overall system size and weight while also reducing its energy requirements. Previous efforts relied on external heat exchangers to recover the waste heat and recycle it to the oxidizer to minimize the system's power requirements; however, these units contribute weight and volume burdens to the overall system. They also result in excess heat loss due to the separation of the HTCO and the heat recuperator, resulting in lower overall efficiency. Improvements in the recuperative efficiency and close coupling of HTCO and heat recuperator lead to reductions in system energy requirements and startup time. Results from testing HTCO units integrated with heat recuperators at a variety of scales for cabin air quality control and heat melt compactor applications are reported and their benefits over previous iterations of the HTCO and heat recuperator assembly are quantified in this paper.

  2. Long-term (1992-2004) record of lead, cadmium, and zinc air contamination in Warsaw, Poland: determination by chemical analysis of moss bags and leaves of Crimean linden.

    PubMed

    Dmuchowski, Wojciech; Bytnerowicz, Andrzej

    2009-12-01

    Between 1992 and 2004, air contamination with lead (Pb), cadmium (Cd), and zinc (Zn) in Warsaw, Poland, was monitored annually with moss (Sphagnum fallax) bags on a network of 230 sites covering the entire city. During the study the highest contamination was near the Warszawa Steel Mill, northwestern Warsaw. Lead concentrations in moss bags decreased in time, while those of Cd and Zn did not show clear trends. Between 1994 and 2004, Pb, Cd, and Zn were also monitored in the Crimean linden (Tilia Euchlora) foliage along the main city avenue and in a northwestern warsaw park. Lead concentrations decreased more near the avenue than in the park, indicating that the phasing-out of leaded gasoline had a major effect on reduced Pb contamination in Warsaw. At the same time, foliar concentrations of Cd and Zn in both areas decreased much less.

  3. Performance of the Proposed New Federal Reference Methods for Measuring Ozone Concentrations in Ambient Air

    EPA Science Inventory

    The current Federal Reference Method (FRM) for measuring concentrations of ozone in ambient air, described in EPA regulations at 40 CFR Part 50, Appendix D, is based on the dry, gas-phase, chemiluminescence reaction between ethylene (C2H4) and any ozone (O

  4. Effect of geocoding errors on traffic-related air pollutant exposure and concentration estimates

    EPA Science Inventory

    Exposure to traffic-related air pollutants is highest very near roads, and thus exposure estimates are sensitive to positional errors. This study evaluates positional and PM2.5 concentration errors that result from the use of automated geocoding methods and from linearized approx...

  5. Evaluation and Comparison of Chemiluminescence and UV Photometric Methods for Measuring Ozone Concentrations in Ambient Air

    EPA Science Inventory

    The current Federal Reference Method (FRM) for measuring concentrations of ozone in ambient air is based on the dry, gas-phase, chemiluminescence reaction between ethylene (C2H4) and any ozone (O3) that may be p...

  6. 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...

  7. Bioaccumulation Potential Of Air Contaminants: Combining Biological Allometry, Chemical Equilibrium And Mass-Balances To Predict Accumulation Of Air Pollutants In Various Mammals

    SciTech Connect

    Veltman, Karin; McKone, Thomas E.; Huijbregts, Mark A.J.; Hendriks, A. Jan

    2009-03-01

    In the present study we develop and test a uniform model intended for single compartment analysis in the context of human and environmental risk assessment of airborne contaminants. The new aspects of the model are the integration of biological allometry with fugacity-based mass-balance theory to describe exchange of contaminants with air. The developed model is applicable to various mammalian species and a range of chemicals, while requiring few and typically well-known input parameters, such as the adult mass and composition of the species, and the octanol-water and air-water partition coefficient of the chemical. Accumulation of organic chemicals is typically considered to be a function of the chemical affinity forlipid components in tissues. Here, we use a generic description of chemical affinity for neutral and polar lipids and proteins to estimate blood-air partition coefficients (Kba) and tissue-air partition coefficients (Kta) for various mammals. This provides a more accurate prediction of blood-air partition coefficients, as proteins make up a large fraction of total blood components. The results show that 75percent of the modeled inhalation and exhalation rate constants are within a factor of 2 from independent empirical values for humans, rats and mice, and 87percent of the predicted blood-air partition coefficients are within a factor of 5 from empirical data. At steady-state, the bioaccumulation potential of air pollutants is shown to be mainly a function of the tissue-air partition coefficient and the biotransformation capacity of the species and depends weakly on the ventilation rate and the cardiac output of mammals.

  8. Effects of warming on uptake and translocation of cadmium (Cd) and copper (Cu) in a contaminated soil-rice system under Free Air Temperature Increase (FATI).

    PubMed

    Ge, Li-Qiang; Cang, Long; Liu, Hui; Zhou, Dong-Mei

    2016-07-01

    Global warming has received growing attentions about its potential threats to human in recent, however little is known about its effects on transfer of heavy metals in agro-ecosystem, especially for Cd in rice. Pot experiments were conducted to evaluate Cd/Cu translocation in a contaminated soil-rice system under Free Air Temperature Increase (FATI). The results showed that warming gradually decreased soil porewater pH and increased water-soluble Cd/Cu concentration, reduced formation of iron plaque on root surface, and thus significantly increased total uptake of Cd/Cu by rice. Subsequently, warming significantly promoted Cd translocation from root to shoot, and increased Cd distribution percentage in shoot, while Cu was not significantly affected. Enhanced Cd uptake and translocation synergistically resulted in higher rice grain contamination with increasing concentration from 0.27 to 0.65 and 0.14-0.40 mg kg(-1) for Indica and Japonica rice, respectively. However increase of Cu in brown grain was only attributed to its uptake enhancement under warming. Our study provides a new understanding about the food production insecurity of heavy metal contaminated soil under the future global warming.

  9. Study on decomposition of indoor air contaminants by pulsed atmospheric microplasma.

    PubMed

    Shimizu, Kazuo; Kuwabara, Tomoya; Blajan, Marius

    2012-10-29

    Decomposition of formaldehyde (HCHO) by a microplasma reactor in order to improve Indoor Air Quality (IAQ) was achieved. HCHO was removed from air using one pass through reactor treatment (5 L/min). From an initial concentration of HCHO of 0.7 ppm about 96% was removed in one pass treatment using a discharge power of 0.3 W provided by a high voltage amplifier and a Marx Generator with MOSFET switches as pulsed power supplies. Moreover microplasma driven by the Marx Generator did not generate NOx as detected by a chemiluminescence NOx analyzer. In the case of large volume treatment the removal ratio of HCHO (initial concentration: 0.5 ppm) after 60 minutes was 51% at 1.2 kV when using HV amplifier considering also a 41% natural decay ratio of HCHO. The removal ratio was 54% at 1.2 kV when a Marx Generator energized the electrodes with a 44% natural decay ratio after 60 minutes of treatment.

  10. Ozone concentrations and damage for realistic future European climate and air quality scenarios

    NASA Astrophysics Data System (ADS)

    Hendriks, Carlijn; Forsell, Nicklas; Kiesewetter, Gregor; Schaap, Martijn; Schöpp, Wolfgang

    2016-11-01

    Ground level ozone poses a significant threat to human health from air pollution in the European Union. While anthropogenic emissions of precursor substances (NOx, NMVOC, CH4) are regulated by EU air quality legislation and will decrease further in the future, the emissions of biogenic NMVOC (mainly isoprene) may increase significantly in the coming decades if short-rotation coppice plantations are expanded strongly to meet the increased biofuel demand resulting from the EU decarbonisation targets. This study investigates the competing effects of anticipated trends in land use change, anthropogenic ozone precursor emissions and climate change on European ground level ozone concentrations and related health and environmental impacts until 2050. The work is based on a consistent set of energy consumption scenarios that underlie current EU climate and air quality policy proposals: a current legislation case, and an ambitious decarbonisation case. The Greenhouse Gas-Air Pollution Interactions and Synergies (GAINS) integrated assessment model was used to calculate air pollutant emissions for these scenarios, while land use change because of bioenergy demand was calculated by the Global Biosphere Model (GLOBIOM). These datasets were fed into the chemistry transport model LOTOS-EUROS to calculate the impact on ground level ozone concentrations. Health damage because of high ground level ozone concentrations is projected to decline significantly towards 2030 and 2050 under current climate conditions for both energy scenarios. Damage to plants is also expected to decrease but to a smaller extent. The projected change in anthropogenic ozone precursor emissions is found to have a larger impact on ozone damage than land use change. The increasing effect of a warming climate (+2-5 °C across Europe in summer) on ozone concentrations and associated health damage, however, might be higher than the reduction achieved by cutting back European ozone precursor emissions. Global

  11. Autism spectrum disorder prevalence and associations with air concentrations of lead, mercury, and arsenic.

    PubMed

    Dickerson, Aisha S; Rahbar, Mohammad H; Bakian, Amanda V; Bilder, Deborah A; Harrington, Rebecca A; Pettygrove, Sydney; Kirby, Russell S; Durkin, Maureen S; Han, Inkyu; Moyé, Lemuel A; Pearson, Deborah A; Wingate, Martha Slay; Zahorodny, Walter M

    2016-07-01

    Lead, mercury, and arsenic are neurotoxicants with known effects on neurodevelopment. Autism spectrum disorder (ASD) is a neurodevelopmental disorder apparent by early childhood. Using data on 4486 children with ASD residing in 2489 census tracts in five sites of the Centers for Disease Control and Prevention's Autism and Developmental Disabilities Monitoring (ADDM) Network, we used multi-level negative binomial models to investigate if ambient lead, mercury, and arsenic concentrations, as measured by the US Environmental Protection Agency National-Scale Air Toxics Assessment (EPA-NATA), were associated with ASD prevalence. In unadjusted analyses, ambient metal concentrations were negatively associated with ASD prevalence. After adjusting for confounding factors, tracts with air concentrations of lead in the highest quartile had significantly higher ASD prevalence than tracts with lead concentrations in the lowest quartile (prevalence ratio (PR) = 1.36; 95 '% CI: 1.18, 1.57). In addition, tracts with mercury concentrations above the 75th percentile (>1.7 ng/m(3)) and arsenic concentrations below the 75th percentile (≤0.13 ng/m(3)) had a significantly higher ASD prevalence (adjusted RR = 1.20; 95 % CI: 1.03, 1.40) compared to tracts with arsenic, lead, and mercury concentrations below the 75th percentile. Our results suggest a possible association between ambient lead concentrations and ASD prevalence and demonstrate that exposure to multiple metals may have synergistic effects on ASD prevalence.

  12. Total internal reflection-based planar waveguide solar concentrator with symmetric air prisms as couplers.

    PubMed

    Xie, Peng; Lin, Huichuan; Liu, Yong; Li, Baojun

    2014-10-20

    We present a waveguide coupling approach for planar waveguide solar concentrator. In this approach, total internal reflection (TIR)-based symmetric air prisms are used as couplers to increase the coupler reflectivity and to maximize the optical efficiency. The proposed concentrator consists of a line focusing cylindrical lens array over a planar waveguide. The TIR-based couplers are located at the focal line of each lens to couple the focused sunlight into the waveguide. The optical system was modeled and simulated with a commercial ray tracing software (Zemax). Results show that the system used with optimized TIR-based couplers can achieve 70% optical efficiency at 50 × geometrical concentration ratio, resulting in a flux concentration ratio of 35 without additional secondary concentrator. An acceptance angle of ± 7.5° is achieved in the x-z plane due to the use of cylindrical lens array as the primary concentrator.

  13. (Environmental investigation of ground water contamination at Wright-Patterson Air Force Base, Ohio)

    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.

  14. Oxidative Nitration of Styrenes for the Recycling of Low-Concentrated Nitrogen Dioxide in Air.

    PubMed

    Hofmann, Dagmar; de Salas, Cristina; Heinrich, Markus R

    2015-09-21

    The oxidative nitration of styrenes in ethyl acetate represents a metal-free, environmentally friendly, and sustainable technique to recover even low concentrations of NO2 in air. Favorable features are that the product mixture comprising nitroalcohols, nitroketones, and nitro nitrates simplifies at lower concentrations of NO2 . Experiments in a miniplant-type 10 L wet scrubber demonstrated that the recycling technique is well applicable on larger scales at which initial NO2 concentrations of >10 000 ppm were reliably reduced to less than 40 ppm.

  15. Ozone concentration in leaf intercellular air spaces is close to zero

    SciTech Connect

    Laisk, A.; Moldau, H. ); Kull, O. )

    1989-07-01

    Transpiration and ozone uptake rates were measured simultaneously in sunflower leaves at different stomatal openings and various ozone concentrations. Ozone uptake rates were proportional to the ozone concentration up to 1500 nanoliters per liter. The leaf gas phase diffusion resistance (stomatal plus boundary layer) to water vapor was calculated and converted to the resistance to ozone multiplying it by the theoretical ratio of diffusion coefficients for water vapor and ozone in air (1.67). The ozone concentration in intercellular air spaces calculated from the ozone uptake rate and diffusion resistance to ozone scattered around zero. The ozone concentration in intercellular air spaces was measured directly bu supplying ozone to the leaf from one side and measuring the equilibrium concentration above the other side, and it was found to be zero. The total leaf resistance to ozone was proportional to the gas phase resistance to water vapor with a coefficient of 1.68. It is concluded that ozone enters the leaf by diffusion through the stomata, and is rapidly decomposed in cell walls and plasmalemma.

  16. Forecasting 7BE concentrations in surface air using time series analysis

    NASA Astrophysics Data System (ADS)

    Bas, María del Carmen; Ortiz, Josefina; Ballesteros, Luisa; Martorell, Sebastián

    2017-04-01

    7Be is a cosmogenic radionuclide widely used as an atmospheric tracer, whose evaluation and forecasting can provide valuable information on changes in the atmospheric behavior. In this study, measurements of 7Be concentrations were made each month during the period 2007-2015 from samples of atmospheric aerosols filtered from the air. The aim was to propose a Seasonal Autoregressive Integrated Moving Average (SARIMA) model to develop an explanatory and predictive model of 7Be air concentrations. The Root Mean Square Error (RMSE) and the Adapted Mean Absolute Percentage Error (AMAPE) were selected to measure forecasting accuracy in identifying the best historical data time window to explain 7Be concentrations. A measure based on the variance of forecast errors was calculated to determine the impact of the model uncertainty on forecasts. We concluded that the SARIMA method is a powerful explanatory and predictive technique for explaining 7Be air concentrations in a longterm series of at least eight years of historical data to forecast 7Be concentration trends up to one year in advance.

  17. Ozone Concentration in Leaf Intercellular Air Spaces Is Close to Zero 1

    PubMed Central

    Laisk, Agu; Kull, Olevi; Moldau, Heino

    1989-01-01

    Transpiration and ozone uptake rates were measured simultaneously in sunflower leaves at different stomatal openings and various ozone concentrations. Ozone uptake rates were proportional to the ozone concentration up to 1500 nanoliters per liter. The leaf gas phase diffusion resistance (stomatal plus boundary layer) to water vapor was calculated and converted to the resistance to ozone multiplying it by the theoretical ratio of diffusion coefficients for water vapor and ozone in air (1.67). The ozone concentration in intercellular air spaces calculated from the ozone uptake rate and diffusion resistance to ozone scattered around zero. The ozone concentration in intercellular air spaces was measured directly by supplying ozone to the leaf from one side and measuring the equilibrium concentration above the other side, and it was found to be zero. The total leaf resistance to ozone was proportional to the gas phase resistance to water vapor with a coefficient of 1.68. It is concluded that ozone enters the leaf by diffusion through the stomata, and is rapidly decomposed in cell walls and plasmalemma. PMID:16666867

  18. Short-term concentration of CO2 in the ambient air of Nagpur city.

    PubMed

    Manuel, Jovita A; Gajghate, D G; Hasan, M Z; Singh, R N

    2002-07-01

    Carbon dioxide concentration is an index of total amount of combustion and natural ventilation in an urban environment and therefore required more careful attention for assessment of CO2 level in air environment. First time, an attempt was made to monitor CO2 levels in Ambient Air of Nagpur during August 2001-December 2001 at Industrial, Commercial and Residential sites. The largest amount of CO2 occurred at night due to darkness which depresses the photosynthesis to its lowest level. The lowest concentration of CO2 was showed in afternoon hours when photosynthesis is at its maximum. The average concentration of CO2 was found to be 361, 366 and 339 ppm at Industrial, Commercial and Industrial sites respectively. This generation of database of ambient CO2 will help to formulate the strategy for prevention of global warming phenomenon.

  19. Relevance of air conditioning for 222Radon concentration in shops of the Savona Province, Italy.

    PubMed

    Panatto, Donatella; Ferrari, Paola; Lai, Piero; Gallelli, Giovanni

    2006-02-15

    Radon (222Rn) concentration was evaluated in shops of the Savona Province, Italy, between summer 2002 and winter 2002-2003. The main characteristics of each shops were recorded through a questionnaire investigating the ventilation rate and factors related to 222Rn precursors in the soil and the construction materials. The main variables that were related to radon concentration were the following: age of the building, level of the shop above ground, season of the year, wind exposure, active windows, and type of heating system. Shops equipped with individual air heating/conditioning systems exhibited radon concentrations that were three times higher than those of shops heated by centralized furnaces. Our data indicate that the level of pollution in the shops was of medium level, with an expected low impact on the salespersons' health. Only in wintertime, the action level of 200 Bq m(-3) for the confined environment was reached in 10 shops equipped with individual air heating/conditioning systems.

  20. The effect of a zero-concentration sink on contaminant transport and remedial-action designs for the Weldon Spring quarry, Weldon Spring, Missouri

    SciTech Connect

    Tomasko, D.

    1990-04-01

    One-dimensional analytical expressions are developed to simulate two processes in a homogeneous porous medium: contaminant transport through a porous medium that has a zero-concentration sink located at a finite distance from a step-function source; and contaminant transport through a porous medium that has an initial steady-state distribution corresponding to a constant strength source and zero-concentration sink separated by a finite distance. The governing equations are cast in dimensionless form, making use of the flow system's Peclet number. Evaluation of the analytical expressions is accomplished by numerical inversion of Laplace-space concentrations using either a full Fourier series approach with acceleration, or the Stehfest algorithm. The analytical expressions are used to evaluate possible contaminant conditions at the Weldon Spring quarry near Weldon Spring, Missouri. The following results have been found: contaminant concentrations should be at or near steady-state conditions; the spatial distribution of contaminants should be a function of the flow system's Peclet number; contaminant concentrations near the Femme Osage Slough should approach zero; contaminant concentrations near the quarry during dewatering and bulk-waste removal should monotonically decrease with time; and the spatial distribution of contaminants during remedial activities should be relatively flat, especially near the dewatering pumps. Future work will entail evaluating existing radionuclide or chemical concentration data to determine the applicability of the proposed contaminant transport model and to improve the hydrogeological conceptualization of the quarry area and vicinity. 20 refs., 27 figs.

  1. Fungal spore concentrations in two haematopoietic stem cell transplantation (HSCT) units containing distinct air control systems.

    PubMed

    Brun, C P; Miron, D; Silla, L M R; Pasqualotto, A C

    2013-04-01

    Invasive fungal diseases have emerged as important causes of morbidity and mortality in haematological patients. In this study air samples were collected in two haematopoietic stem cell transplantation (HSCT) units, in which distinct air-control systems were in place. In hospital 1 no high-efficiency particulate air (HEPA) filter was available whereas in hospital 2 HSCT rooms were equipped with HEPA filters, with positive air pressure in relation to the corridor. A total of 117 samples from rooms, toilets and corridors were obtained during December 2009 to January 2011, using a six-stage Andersen sampler. In both hospitals, the concentration of potentially pathogenic fungi in the air was reduced in patients' rooms compared to corridors (P < 0·0001). Despite the presence of a HEPA filter in hospital 2, rooms in both hospitals showed similar concentrations of potentially pathogenic fungi (P = 0·714). These findings may be explained by the implementation of additional protective measures in hospital 1, emphasizing the importance of such measures in protected environments.

  2. Concentrations and decay rates of ozone in indoor air in dependence on building and surface materials.

    PubMed

    Moriske, H J; Ebert, G; Konieczny, L; Menk, G; Schöndube, M

    1998-08-01

    The decay of ozone in indoor air was measured in a closed chamber after contact with different building materials and residential surfaces. The tested materials were: vinyl wall paper, woodchip paper, plywood, latex paint, fitted carpet, and plaster. In the summer of 1996, the entry of ozone from ambient air into indoor air during ventilation and the ozone decay in indoor air, after windows had been closed again, were studied. Measurements were done in a residential house on the outskirts of Berlin. The following results were gained: the chamber measurements showed a decay of ozone after contact with most of the materials put inside the chamber. Higher decay rates have been obtained for wall papers, plywood, fitted carpet and plaster. As described in the literature, ozone is able to react with olefines inside the materials and is able to form formaldehyde and other components. This formation of formaldehyde could also be confirmed in our investigations. Thus, in most cases, the formaldehyde concentrations were lower than the German guideline value of 0.1 ppm. The formation of formaldehyde could be prevented when a special wall paper that was coated with activated carbon was used. In the house, a complete ozone diffusion into indoor air took place during ventilation within 30 min. After closing the windows, the ozone concentrations decreased to the basic level before ventilation within 60-90 min.

  3. Relationships between environmental organochlorine contaminant residues, plasma corticosterone concentrations, and intermediary metabolic enzyme activities in Great Lakes herring gull embryos.

    PubMed Central

    Lorenzen, A; Moon, T W; Kennedy, S W; Glen, G A

    1999-01-01

    Experiments were conducted to survey and detect differences in plasma corticosterone concentrations and intermediary metabolic enzyme activities in herring gull (Larus argentatus) embryos environmentally exposed to organochlorine contaminants in ovo. Unincubated fertile herring gull eggs were collected from an Atlantic coast control site and various Great Lakes sites in 1997 and artificially incubated in the laboratory. Liver and/or kidney tissues from approximately half of the late-stage embryos were analyzed for the activities of various intermediary metabolic enzymes known to be regulated, at least in part, by corticosteroids. Basal plasma corticosterone concentrations were determined for the remaining embryos. Yolk sacs were collected from each embryo and a subset was analyzed for organochlorine contaminants. Regression analysis of individual yolk sac organochlorine residue concentrations, or 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TEQs), with individual basal plasma corticosterone concentrations indicated statistically significant inverse relationships for polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans (PCDDs/PCDFs), total polychlorinated biphenyls (PCBs), non-ortho PCBs, and TEQs. Similarly, inverse relationships were observed for the activities of two intermediary metabolic enzymes (phosphoenolpyruvate carboxykinase and malic enzyme) when regressed against PCDDs/PCDFs. Overall, these data suggest that current levels of organochlorine contamination may be affecting the hypothalamo-pituitary-adrenal axis and associated intermediary metabolic pathways in environmentally exposed herring gull embryos in the Great Lakes. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 PMID:10064546

  4. Low-CCN concentration air masses over the eastern North Atlantic: Seasonality, meteorology, and drivers

    NASA Astrophysics Data System (ADS)

    Wood, Robert; Stemmler, Jayson D.; Rémillard, Jasmine; Jefferson, Anne

    2017-01-01

    A 20 month cloud condensation nucleus concentration (NCCN) data set from Graciosa Island (39°N, 28°W) in the remote North Atlantic is used to characterize air masses with low cloud condensation nuclei (CCN) concentrations. Low-CCN events are defined as 6 h periods with mean NCCN<20 cm-3 (0.1% supersaturation). A total of 47 low-CCN events are identified. Surface, satellite, and reanalysis data are used to explore the meteorological and cloud context for low-CCN air masses. Low-CCN events occur in all seasons, but their frequency was 3 times higher in December-May than during June-November. Composites show that many of the low-CCN events had a common meteorological basis that involves southerly low-level flow and rather low wind speeds at Graciosa. Anomalously low pressure is situated to the west of Graciosa during these events, but back trajectories and lagged SLP composites indicate that low-CCN air masses often originate as cold air outbreaks to the north and west of Graciosa. Low-CCN events were associated with low cloud droplet concentrations (Nd) at Graciosa, but liquid water path (LWP) during low-CCN events was not systematically different from that at other times. Satellite Nd and LWP estimates from MODIS collocated with Lagrangian back trajectories show systematically lower Nd and higher LWP several days prior to arrival at Graciosa, consistent with the hypothesis that observed low-CCN air masses are often formed by coalescence scavenging in thick warm clouds, often in cold air outbreaks.

  5. Impact of traffic flows and wind directions on air pollution concentrations in Seoul, Korea

    NASA Astrophysics Data System (ADS)

    Kim, Youngkook; Guldmann, Jean-Michel

    2011-05-01

    Vehicle emissions are responsible for a substantial share of urban air pollution concentrations. Various integrated air quality modeling systems have been developed to analyze the consequences of air pollution caused by traffic flows. However, the quantitative relationship between vehicle-kilometers-traveled (VKT) and pollution concentrations while considering wind direction effects has rarely been explored in the context of land-use regression models (LUR). In this research, VKTs occurring within circular buffers around air pollution monitoring stations are simulated, using a traffic assignment model, and weighted by eight wind directions frequencies. The relationships between monitored pollution concentrations and weighted VKTs are estimated using regression analysis. In general, the wind direction weighted VKT variable increases the explanatory power of the models, particularly for nitrogen dioxide and carbon monoxide. The case of ozone is more complex, due to the effects of solar radiation, which appears to overwhelm the effects of wind direction in the afternoon hours. The statistical significance of the weighted VKT variable is high, which makes the models appropriate for impact analysis of traffic flow growth.

  6. Air concentrations of PBDEs on in-flight airplanes and assessment of flight crew inhalation exposure.

    PubMed

    Allen, Joseph G; Sumner, Ann Louise; Nishioka, Marcia G; Vallarino, Jose; Turner, Douglas J; Saltman, Hannah K; Spengler, John D

    2013-07-01

    To address the knowledge gaps regarding inhalation exposure of flight crew to polybrominated diphenyl ethers (PBDEs) on airplanes, we measured PBDE concentrations in air samples collected in the cabin air at cruising altitudes and used Bayesian Decision Analysis (BDA) to evaluate the likelihood of inhalation exposure to result in the average daily dose (ADD) of a member of the flight crew to exceed EPA Reference Doses (RfDs), accounting for all other aircraft and non-aircraft exposures. A total of 59 air samples were collected from different aircraft and analyzed for four PBDE congeners-BDE 47, 99, 100 and 209 (a subset were also analyzed for BDE 183). For congeners with a published RfD, high estimates of ADD were calculated for all non-aircraft exposure pathways and non-inhalation exposure onboard aircraft; inhalation exposure limits were then derived based on the difference between the RfD and ADDs for all other exposure pathways. The 95th percentile measured concentrations of PBDEs in aircraft air were <1% of the derived inhalation exposure limits. Likelihood probabilities of 95th percentile exposure concentrations >1% of the defined exposure limit were zero for all congeners with published RfDs.

  7. Biomimetic air sampling for detection of low concentrations of molecules and bioagents : LDRD 52744 final report.

    SciTech Connect

    Hughes, Robert Clark

    2003-12-01

    Present methods of air sampling for low concentrations of chemicals like explosives and bioagents involve noisy and power hungry collectors with mechanical parts for moving large volumes of air. However there are biological systems that are capable of detecting very low concentrations of molecules with no mechanical moving parts. An example is the silkworm moth antenna which is a highly branched structure where each of 100 branches contains about 200 sensory 'hairs' which have dimensions of 2 microns wide by 100 microns long. The hairs contain about 3000 pores which is where the gas phase molecules enter the aqueous (lymph) phase for detection. Simulations of diffusion of molecules indicate that this 'forest' of hairs is 'designed' to maximize the extraction of the vapor phase molecules. Since typical molecules lose about 4 decades in diffusion constant upon entering the liquid phase, it is important to allow air diffusion to bring the molecule as close to the 'sensor' as possible. The moth acts on concentrations as low as 1000 molecules per cubic cm. (one part in 1e16). A 3-D collection system of these dimensions could be fabricated by micromachining techniques available at Sandia. This LDRD addresses the issues involved with extracting molecules from air onto micromachined structures and then delivering those molecules to microsensors for detection.

  8. Sampling artifacts in active air sampling of semivolatile organic contaminants: Comparing theoretical and measured artifacts and evaluating implications for monitoring networks.

    PubMed

    Melymuk, Lisa; Bohlin-Nizzetto, Pernilla; Prokeš, Roman; Kukučka, Petr; Klánová, Jana

    2016-10-01

    The effects of sampling artifacts are often not fully considered in the design of air monitoring with active air samplers. Semivolatile organic contaminants (SVOCs) are particularly vulnerable to a range of sampling artifacts because of their wide range of gas-particle partitioning and degradation rates, and these can lead to erroneous measurements of air concentrations and a lack of comparability between sites with different environmental and sampling conditions. This study used specially adapted filter-sorbent sampling trains in three types of active air samplers to investigate breakthrough of SVOCs, and the possibility of other sampling artifacts. Breakthrough volumes were experimentally determined for a range of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs) in sampling volumes from 300 to 10,000 m(3), and sampling durations of 1-7 days. In parallel, breakthrough was estimated based on theoretical sorbent-vapor pressure relationships. The comparison of measured and theoretical determinations of breakthrough demonstrated good agreement between experimental and estimated breakthrough volumes, and showed that theoretical breakthrough estimates should be used when developing air monitoring protocols. Significant breakthrough in active air samplers occurred for compounds with vapor pressure >0.5 Pa at volumes <700 m(3). Sample volumes between 700 and 10,000 m(3) may lead to breakthrough for compounds with vapor pressures between 0.005 and 0.5 Pa. Breakthrough is largely driven by sample volume and compound volatility (therefore indirectly by temperature) and is independent of sampler type. The presence of significant breakthrough at "typical" sampling conditions is relevant for air monitoring networks, and may lead to under-reporting of more volatile SVOCs.

  9. Comparison of Air Impaction and Electrostatic Dust Collector Sampling Methods to Assess Airborne Fungal Contamination in Public Buildings.

    PubMed

    Normand, Anne-Cécile; Ranque, Stéphane; Cassagne, Carole; Gaudart, Jean; Sallah, Kankoé; Charpin, Denis-André; Piarroux, Renaud

    2016-03-01

    Many ailments can be linked to exposure to indoor airborne fungus. However, obtaining a precise measurement of airborne fungal levels is complicated partly due to indoor air fluctuations and non-standardized techniques. Electrostatic dust collector (EDC) sampling devices have been used to measure a wide range of airborne analytes, including endotoxins, allergens, β-glucans, and microbial DNA in various indoor environments. In contrast, viable mold contamination has only been assessed in highly contaminated environments such as farms and archive buildings. This study aimed to assess the use of EDCs, compared with repeated air-impactor measurements, to assess airborne viable fungal flora in moderately contaminated indoor environments. Indoor airborne fungal flora was cultured from EDCs and daily air-impaction samples collected in an office building and a daycare center. The quantitative fungal measurements obtained using a single EDC significantly correlated with the cumulative measurement of nine daily air impactions. Both methods enabled the assessment of fungal exposure, although a few differences were observed between the detected fungal species and the relative quantity of each species. EDCs were also used over a 32-month period to monitor indoor airborne fungal flora in a hospital office building, which enabled us to assess the impact of outdoor events (e.g. ground excavations) on the fungal flora levels on the indoor environment. In conclusion, EDC-based measurements provided a relatively accurate profile of the viable airborne flora present during a sampling period. In particular, EDCs provided a more representative assessment of fungal levels compared with single air-impactor sampling. The EDC technique is also simpler than performing repetitive air-impaction measures over the course of several consecutive days. EDC is a versatile tool for collecting airborne samples and was efficient for measuring mold levels in indoor environments.

  10. Application of passive sampling for measuring dissolved concentrations of organic contaminants in the water column at three marine superfund sites.

    PubMed

    Burgess, Robert M; Lohmann, Rainer; Schubauer-Berigan, Joseph P; Reitsma, Pamela; Perron, Monique M; Lefkovitz, Lisa; Cantwell, Mark G

    2015-08-01

    Currently, there is an effort under way to encourage remedial project managers at contaminated sites to use passive sampling to collect freely dissolved concentrations (Cfree ) of hydrophobic organic contaminants to improve site assessments. The objective of the present study was to evaluate the use of passive sampling for measuring water column Cfree for several hydrophobic organic contaminants at 3 US Environmental Protection Agency Superfund sites. Sites investigated included New Bedford Harbor (New Bedford, MA, USA), Palos Verdes Shelf (Los Angeles, CA, USA), and Naval Station Newport (Newport, RI, USA); and the passive samplers evaluated were polyethylene, polydimethylsiloxane-coated solid-phase microextraction fibers, semipermeable membrane devices, and polyoxymethylene. In general, the different passive samplers demonstrated good agreement, with Cfree values varying by a factor of 2 to 3. Further, at New Bedford Harbor, where conventional water sample concentrations were also measured (i.e., grab samples), passive sampler-based Cfree values agreed within a factor of 2. These findings suggest that all of the samplers were experiencing and measuring similar Cfree during their respective deployments. Also, at New Bedford Harbor, a strong log-linear, correlative, and predictive relationship was found between polyethylene passive sampler accumulation and lipid-normalized blue mussel bioaccumulation of polychlorinated biphenyls (r(2)  = 0.92, p < 0.05). The present study demonstrates the utility of passive sampling for generating scientifically accurate water column Cfree values, which is critical for making informed environmental management decisions at contaminated sediment sites.

  11. Cytochrome P450 and contaminant concentrations in nestling black-crowned night-herons and their interrelation with sibling embryos

    USGS Publications Warehouse

    Rattner, B.A.; Melancon, M.J.; Custer, T.W.; Hothem, R.L.

    1996-01-01

    Hepatic cytochrome P450-associated monooxygenase activities were measured in 11-day-old nestling black-crowned night-herons (Nycticorax nycticorax) collected from a reference site (next to Chincoteague National Wildlife Refuge, VA) and three contaminated sites (Cat Island, Green Bay, WI; Bair Island, San Francisco Bay, CA; West Marin Island, San Francisco Bay, CA). Arylhydrocarbon hydroxylase (AHH) and benzyloxyresorufin-O-dealkylase (BROD) activities of nestlings from contaminated sites were only slightly elevated (less than threefold) compared to the reference site. Organochlorine pesticide and total PCB concentrations in nestlings were greatest at contaminated sites, although much lower than found in concurrently collected eggs and pipping embryos. Pollutant concentrations of nestlings were rarely associated with monooxygenase activity. In contrast, concurrently collected pipping heron embryos (often siblings of the nestlings) exhibited pronounced monooxygenase induction (means at contaminated sites elevated up to sevenfold and values of some embryos exceeded 25-fold induction). Furthermore, monooxygenase activity of pipping embryos was significantly correlated with total PCBs, arylhydrocarbon receptor-active PCB congeners and toxic equivalents. The modest monooxygenase responses of heron nestlings suggest that this biomarker may have only limited value during this rapid-growth life stage.

  12. Cytochrome P450 and contaminant concentrations in nestling black-crowned night-herons and their interrelation with sibling embryos

    USGS Publications Warehouse

    Rattner, Barnett A.; Melancon, Mark J.; Custer, Thomas W.; Hothem, Roger L.

    1996-01-01

    Hepatic cytochrome P450-associated monooxygenase activities were measured in 11-d-old nestling black-crowned night-herons (Nycticorax nycticorax) collected from a reference site (next to Chincoteague National Wildlife Refuge, VA, USA) and three contaminated sites (Cat Island, Green Bay, WI, USA; Bair Island, San Francisco Bay, CA, USA; and West Marin Island, San Francisco Bay, CA, USA). Arylhydrocarbon hydroxylase and benzyloxyresorufin-O-dealkylase activities of nestlings from contaminated sites were only slightly elevated (less than threefold) compared with the reference site. Organochlorine pesticide and total polychlorinated biphenyl (PCB) concentrations in nestlings were greatest at contaminated sites, although much lower than found in concurrently collected eggs and pipping embryos. Pollutant concentrations of nestlings were rarely associated with monooxygenase activity. In contrast, concurrently collected pipping heron embryos (often siblings of the nestlings) exhibited pronounced monooxygenase induction (means at contaminated sites were elevated up to sevenfold and values of some embryos exceeded 25-fold induction). Furthermore, monooxygenase activity of pipping embryos was significantly correlated with total PCBs, arylhydrocarbon receptor-active PCB congeners, and toxic equivalents. The modest monooxygenase responses of heron nestlings suggest that this biomarker may have only limited value during this rapid-growth life stage.

  13. Cytochrome P450 and contaminant concentrations in nestling black-crowned night-herons and their interrelation with sibling embryos

    SciTech Connect

    Rattner, B.A.; Melancon, M.J.; Custer, T.W.; Hothem, R.L.

    1996-05-01

    Hepatic cytochrome P450-associated monooxygenase activities were measured in 11-d-old nestling black-crowned night-herons (Nycticorax nycticorax) collected from a reference site (next to Chincoteague National Wildlife Reguge, VA, USA) and three contaminated sites (Cat Island, Green Bay, WI, USA; Bair Island, San Francisco Bay, CA, USA; and West Marin Island, San Francisco Bay, CA, USA). Arylhydrocarbon hydroxylase and benzyloxyresorufin-O-dealkylase activities of nestlings from contaminated sites were only slightly elevated (less than threefold) compared with the reference site. Organochlorine pesticide and total polychlorinated biphenyl (PCB) concentrations in nestlings were greatest at contaminated sites, although much lower than found in concurrently collected eggs and pipping embryos. Pollutant concentrations of nestlings were rarely associated with monooxygenase activity. In contrast, concurrently collected pipping heron embryos (often siblings of the nestlings) exhibited pronounced monooxygenase induction (means at contaminated sites were elevated up to sevenfold and values of some embryos exceeded 25-fold induction). Furthermore, monooxygenase activity of pipping embryos was significantly correlated with total PCBs, arylhydrocarbon receptor-active PCB congeners, and toxic equivalents. The modest monooxygenase responses of heron nestlings suggest that this biomarker may have only limited value during this rapid-growth life stage.

  14. Influences of ammonia contamination on leaching from air-pollution-control residues.

    PubMed

    Guan, Zhenzhen; Chen, Dezhen; Astrup, Thomas Fruergaard

    2014-12-01

    Application of selective non-catalytic reduction systems at municipal solid waste incinerators (MSWIs) often involves over-stoichiometric injection of ammonia into flue gases. Un-reacted ammonia may be deposited on fly ash particles and can ultimately influence the leaching behaviour of air-pollution-control (APC) residues. Batch tests were conducted to investigate the impacts of ammonia levels on leaching of a range of metals (sodium, potassium, calcium, aluminium, chromium, iron, lead, cadmium, copper, nickel and zinc), as well as chloride and dissolved organic carbon (DOC). Specific conductivity was also identified to reflect the soluble components. The results showed that with ammonia concentrations rising from a background level of 4 to 26,400 mg l(-1), the specific conductivity increased by 2-7 times as pH varied from alkaline to acidic values. DOC release was also significantly enhanced with high ammonia levels of 1400 mg l(-1) or higher at pH > 9; however at these high ammonia concentrations, the role of DOC in cadmium, copper, nickel and zinc leaching was negligible. Based on the experimental data, chloride, sodium and potassium were leached at high concentrations regardless of pH and ammonia concentrations. For aluminium, chromium, iron and lead, ammonia had little impact on their leaching behaviour. With respect to cadmium, copper, nickel and zinc, high ammonia concentrations significantly increased leaching in the pH range of 8-12 due to the formation of metal-ammonia complexes, which was also proved in the speciation calculations. However, the overall results suggest that typical levels of ammonia injection in MSWIs are not likely to affect metal leaching from APC residues.

  15. The Impact of Future Emissions Changes on Air Pollution Concentrations and Related Human Health Effects

    NASA Astrophysics Data System (ADS)

    Mikolajczyk, U.; Suppan, P.; Williams, M.

    2015-12-01

    Quantification of potential health benefits of reductions in air pollution on the local scale is becoming increasingly important. The aim of this study is to conduct health impact assessment (HIA) by utilizing regionally and spatially specific data in order to assess the influence of future emission scenarios on human health. In the first stage of this investigation, a modeling study was carried out using the Weather Research and Forecasting (WRF) model coupled with Chemistry to estimate ambient concentrations of air pollutants for the baseline year 2009, and for the future emission scenarios in southern Germany. Anthropogenic emissions for the baseline year 2009 are derived from the emission inventory provided by the Netherlands Organization of Applied Scientific Research (TNO) (Denier van der Gon et al., 2010). For Germany, the TNO emissions were replaced by gridded emission data with a high spatial resolution of 1/64 x 1/64 degrees. Future air quality simulations are carried out under different emission scenarios, which reflect possible energy and climate measures in year 2030. The model set-up included a nesting approach, where three domains with horizontal resolution of 18 km, 6 km and 2 km were defined. The simulation results for the baseline year 2009 are used to quantify present-day health burdens. Concentration-response functions (CRFs) for PM2.5 and NO2 from the WHO Health risks of air Pollution in Europe (HRAPIE) project were applied to population-weighted mean concentrations to estimate relative risks and hence to determine numbers of attributable deaths and associated life-years lost. In the next step, future health impacts of projected concentrations were calculated taking into account different emissions scenarios. The health benefits that we assume with air pollution reductions can be used to provide options for future policy decisions to protect public health.

  16. 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.

  17. Bioremediation of contaminated groundwater

    DOEpatents

    Hazen, Terry C.; Fliermans, Carl B.

    1995-01-01

    An apparatus and method for in situ remediation of contaminated subsurface soil or groundwater contaminated by chlorinated hydrocarbons. A nutrient fluid is selected to stimulate the growth and reproduction of indigenous subsurface microorganisms that are capable of degrading the contaminants; an oxygenated fluid is selected to create a generally aerobic environment for these microorganisms to degrade the contaminants, leaving only pockets that are anaerobic. The nutrient fluid is injected periodically while the oxygenated fluid is injected continuously and both are extracted so that both are drawn across the plume. The nutrient fluid stimulates microbial colony growth; withholding it periodicially forces the larger, healthy colony of microbes to degrade the contaminants. Treatment is continued until the subsurface concentration of contaminants is reduced to an acceptable, preselected level. The nutrient fluid can be methane and the oxygenated fluid air for stimulating production of methanotrophs to break down chlorohydrocarbons, especially trichloroethylene (TCE) and tetrachloroethylene.

  18. Bioremediation of contaminated groundwater

    DOEpatents

    Hazen, T.C.; Fliermans, C.B.

    1995-01-24

    An apparatus and method are described for in situ remediation of contaminated subsurface soil or groundwater contaminated by chlorinated hydrocarbons. A nutrient fluid is selected to stimulate the growth and reproduction of indigenous subsurface microorganisms that are capable of degrading the contaminants. An oxygenated fluid is selected to create a generally aerobic environment for these microorganisms to degrade the contaminants, leaving only pockets that are anaerobic. The nutrient fluid is injected periodically while the oxygenated fluid is injected continuously and both are extracted so that both are drawn across the plume. The nutrient fluid stimulates microbial colony growth. Withholding it periodically forces the larger, healthy colony of microbes to degrade the contaminants. Treatment is continued until the subsurface concentration of contaminants is reduced to an acceptable, preselected level. The nutrient fluid can be methane and the oxygenated fluid air for stimulating production of methanotrophs to break down chlorohydrocarbons, especially trichloroethylene (TCE) and tetrachloroethylene. 3 figures.

  19. Treatment of emerging contaminants in wastewater treatment plants (WWTP) effluents by solar photocatalysis using low TiO2 concentrations.

    PubMed

    Prieto-Rodriguez, L; Miralles-Cuevas, S; Oller, I; Agüera, A; Li Puma, G; Malato, S

    2012-04-15

    The optimal photocatalyst concentration for industrial wastewater treatment in current photoreactor designs is several hundreds of milligrams per liter. However, the elimination of emerging contaminants (ECs), which are present at extremely low concentrations in waste water treatment plants (WWTP) effluents might be accomplished at much lower catalyst (TiO(2)) concentrations. One of the main drawbacks of reducing catalyst loading below the optimum is the loss of useful photons which instead are transmitted through the TiO(2) suspension without being absorbed by the catalyst. Accordingly, in this work, laboratory and solar pilot-scale experiments were performed with real WWTP effluents to evaluate the kinetics of photocatalytic degradation of 52 emerging contaminants under realistic (ppb) concentrations. The analysis of the samples was accomplished by solid phase extraction (SPE) followed by liquid chromatography-mass spectrometry (LC-MS). In view of the results, low concentrations of TiO(2) of the order of tens of milligrams per liter were found to be insufficient for the degradation of the ECs in photoreactors with a short light-path length (29 cm). However, it was established that solar reactors of diameters of several hundreds of millimetres could be used for the efficient removal of ECs from WWTP effluents. The results presented show a general methodology for selecting the most efficient reactor diameter on the basis of the desired catalyst concentration.

  20. Transport of semivolatile organic compounds to the Tibetan Plateau: Monthly resolved air concentrations at Nam Co

    NASA Astrophysics Data System (ADS)

    Xiao, Hang; Kang, Shichang; Zhang, Qianggong; Han, Wenwu; Loewen, Mark; Wong, Fiona; Hung, Hayley; Lei, Ying D.; Wania, Frank

    2010-08-01

    A flow-through sampler was deployed to record the seasonal variability of the atmospheric concentrations of semivolatile organic compounds (SOCs) at a remote research station located close to Nam Co Lake on the Tibetan plateau. Between October 2006 and February 2008, fifteen consecutive one month-long samples, with air volumes ranging from 4,500 to 16,000 m3, were taken and analyzed for polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs). Separate analysis of three polyurethane plugs in series in combination with frontal chromatographic theory allows for the correction of the break-through observed for the most volatile SOCs. The concentrations of Σ56PCB in air range from 0.10 to 2.6 pg·m-3 and are among the lowest values ever reported. Levels of OCPs at Nam Co are generally also very low, particularly during wintertime. The concentrations of hexachlorocyclohexanes (HCHs), endosulfans, and various dichlorodiphenyltrichloroethane (DDT) related substances display a distinct seasonal variability consistent with the monsoon. Back-trajectory analysis reveals that higher OCP levels during summer correlate with air mass origin south of the Himalayas. A high α/γ-HCH ratio and a non-racemic composition of α-HCH during July/August suggest that evaporation from Nam Co Lake contributes to the relatively high concentrations of α-HCH (averaging ca. 91 pg·m-3) recorded in the summertime atmosphere.

  1. Assessment of regional air quality by a concentration-dependent Pollution Permeation Index

    NASA Astrophysics Data System (ADS)

    Liang, Chun-Sheng; Liu, Huan; He, Ke-Bin; Ma, Yong-Liang

    2016-10-01

    Although air quality monitoring networks have been greatly improved, interpreting their expanding data in both simple and efficient ways remains challenging. Therefore, needed are new analytical methods. We developed such a method based on the comparison of pollutant concentrations between target and circum areas (circum comparison for short), and tested its applications by assessing the air pollution in Jing-Jin-Ji, Yangtze River Delta, Pearl River Delta and Cheng-Yu, China during 2015. We found the circum comparison can instantly judge whether a city is a pollution permeation donor or a pollution permeation receptor by a Pollution Permeation Index (PPI). Furthermore, a PPI-related estimated concentration (original concentration plus halved average concentration difference) can be used to identify some overestimations and underestimations. Besides, it can help explain pollution process (e.g., Beijing’s PM2.5 maybe largely promoted by non-local SO2) though not aiming at it. Moreover, it is applicable to any region, easy-to-handle, and able to boost more new analytical methods. These advantages, despite its disadvantages in considering the whole process jointly influenced by complex physical and chemical factors, demonstrate that the PPI based circum comparison can be efficiently used in assessing air pollution by yielding instructive results, without the absolute need for complex operations.

  2. Assessment of regional air quality by a concentration-dependent Pollution Permeation Index

    PubMed Central

    Liang, Chun-Sheng; Liu, Huan; He, Ke-Bin; Ma, Yong-Liang

    2016-01-01

    Although air quality monitoring networks have been greatly improved, interpreting their expanding data in both simple and efficient ways remains challenging. Therefore, needed are new analytical methods. We developed such a method based on the comparison of pollutant concentrations between target and circum areas (circum comparison for short), and tested its applications by assessing the air pollution in Jing-Jin-Ji, Yangtze River Delta, Pearl River Delta and Cheng-Yu, China during 2015. We found the circum comparison can instantly judge whether a city is a pollution permeation donor or a pollution permeation receptor by a Pollution Permeation Index (PPI). Furthermore, a PPI-related estimated concentration (original concentration plus halved average concentration difference) can be used to identify some overestimations and underestimations. Besides, it can help explain pollution process (e.g., Beijing’s PM2.5 maybe largely promoted by non-local SO2) though not aiming at it. Moreover, it is applicable to any region, easy-to-handle, and able to boost more new analytical methods. These advantages, despite its disadvantages in considering the whole process jointly influenced by complex physical and chemical factors, demonstrate that the PPI based circum comparison can be efficiently used in assessing air pollution by yielding instructive results, without the absolute need for complex operations. PMID:27731344

  3. An assessment of contaminant concentrations in toothed whale species of the NW Iberian Peninsula: part II. Trace element concentrations.

    PubMed

    Méndez-Fernandez, Paula; Webster, Lynda; Chouvelon, Tiphaine; Bustamante, Paco; Ferreira, Marisa; González, Angel F; López, Alfredo; Moffat, Colin F; Pierce, Graham J; Read, Fiona L; Russell, Marie; Santos, Maria B; Spitz, Jérôme; Vingada, José V; Caurant, Florence

    2014-06-15

    Concentrations of Ag, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, V and Zn were investigated in the liver and kidney of the five most common toothed whales off the Northwest Iberian Peninsula (NWIP), specifically common dolphin, long-finned pilot whale, harbour porpoise, striped dolphin and bottlenose dolphin. Differences were observed in the bioaccumulation of the above elements between the five species. The differences are probably related to biological factors such as age and sex and/or to ecological factors specific to each species such as feeding habits or bioavailability of the various elements. However, no significant relationship was observed between element accumulation and sex. Pilot whale and striped dolphin showed the highest concentrations of renal Cd and the highest concentrations of hepatic Hg and Se, while bottlenose dolphin showed the highest concentrations of Hg in kidneys. An analysis of inter-elemental relationships showed strong positive correlations between Hg and Se in the five species, however most individuals have Hg:Se molar ratio less than 1:1 indicating an excess of Se compare to Hg. This result, probably reflect the high proportion of young animals in the sample available for this study and/or that these animals had a good health status. We also observed a positive correlation in striped dolphins between Cd and Cu and between Cd and Zn in kidneys. In addition, comparing with other studies world-wide, the element concentrations (Hg and Cd) found in Iberian toothed whales indicate that these populations are not specially threatened by Hg and Cd exposure in the area.

  4. Demonstration of Bioventing for Remediation of Chlorinated Solvent Contamination at Hill Air Force Base, Ogden, Utah, Volume I

    DTIC Science & Technology

    2007-11-02

    This report describes the evaluation of the application of bioventing technology to non-petroleum hydrocarbon impacted soils. Bioventing has been...study and a field pilot-scale demonstration to evaluate the potential for applying bioventing to treat dichlorobenzenes in order to expand the list of...contaminants impacting Air Force and other Department of Defense Installations beyond petroleum hydrocarbons. A pilot-scale bioventing system consisting

  5. 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...

  6. Contribution of ship emissions to the concentration and deposition of air pollutants in Europe

    NASA Astrophysics Data System (ADS)

    Aksoyoglu, S.; Prévôt, A. S. H.; Baltensperger, U.

    2015-11-01

    Emissions from the marine transport sector are one of the least regulated anthropogenic emission sources and contribute significantly to air pollution. Although strict limits were introduced recently for the maximum sulfur content in marine fuels in the SECAs (sulfur emission control areas) and in the EU ports, sulfur emissions outside the SECAs and emissions of other components in all European maritime areas have continued to increase in the last two decades. We have used the air quality model CAMx with and without ship emissions for the year 2006 to determine the effects of international shipping on the annual as well as seasonal concentrations of ozone, primary and secondary components of PM2.5 and the dry and wet deposition of nitrogen and sulfur compounds in Europe. Our results suggest that emissions from international shipping affect the air quality in northern and southern Europe differently and their contributions to the air concentrations vary seasonally. The largest changes in pollutant concentrations due to ship emissions were predicted for summer. Increased concentrations of the primary particle mass were found only along the shipping routes whereas concentrations of the secondary pollutants were affected over a larger area. Concentrations of particulate sulfate increased due to ship emissions in the Mediterranean (up to 60 %), in the English Channel and the North Sea (30-35 %) while increases in particulate nitrate levels were found especially in the north, around the Benelux area (20 %) where there were high NH3 land-based emissions. Our model results showed that not only the atmospheric concentrations of pollutants are affected by ship emissions, but also depositions of nitrogen and sulfur compounds increase significantly along the shipping routes. NOx emissions from the ships especially in the English Channel and the North Sea, cause a decrease in the dry deposition of reduced nitrogen at source regions by moving it from the gas-phase to the

  7. Effect of outside air ventilation rate on volatile organic compound concentrations in a call center

    NASA Astrophysics Data System (ADS)

    Hodgson, A. T.; Faulkner, D.; Sullivan, D. P.; DiBartolomeo, D. L.; Russell, M. L.; Fisk, W. J.

    A study of the relationship between outside air ventilation rate and concentrations of volatile organic compounds (VOCs) generated indoors was conducted in a call center office building. The building, with two floors and a total floor area of 4600 m 2, is located in the San Francisco Bay Area, CA. Ventilation rates were manipulated with the building's four air handling units (AHUs). VOC and CO 2 concentrations in the AHU returns were measured on 7 days during a 13-week period. VOC emission factors were determined for individual zones on days when they were operating at near steady-state conditions. The emission factor data were subjected to principal component (PC) analysis to identify groups of co-varying compounds. Potential sources of the PC vectors were ascribed based on information from the literature. The per occupant CO 2 generation rates were 0.0068-0.0092 l s -1. The per occupant isoprene generation rates of 0.2-0.3 mg h -1 were consistent with the value predicted by mass balance from breath concentration and exhalation rate. The relationships between indoor minus outdoor VOC concentrations and ventilation rate were qualitatively examined for eight VOCs. Of these, acetaldehyde and hexanal, which likely were associated with material sources, and decamethylcyclopentasiloxane, associated with personal care products, exhibited general trends of higher concentrations at lower ventilation rates. For other compounds, a clear inverse relationship between VOC concentrations and ventilation was not observed. The net concentration of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate isomers, examples of low-volatility compounds, changed very little with ventilation likely due to sorption and re-emission effects. These results illustrate that the efficacy of ventilation for controlling VOC concentrations can vary considerably depending upon the operation of the building, the pollutant sources and the physical and chemical processes affecting the pollutants. Thus, source

  8. Aflatoxin contamination of groundnut and maize in Zambia: observed and potential concentrations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maize and groundnut, important staples in Zambia, are susceptible to aflatoxin-producing fungi. Aflatoxins are potent human carcinogens also associated with stunting and immunosuppression. Although health and economic burdens of aflatoxins are well known, patterns of contamination in maize and grou...

  9. EFFECTIVE CONCENTRATIONS OF 6 CONTAMINANTS TO LEMMA MINOR, PIMEPHALES PROMELA, DAPHNIA MAGNA, AND CERIODAPHNIA DUBIA

    EPA Science Inventory

    The research presented here resulted in EC50 and LOEC values for the contaminants copper, cadmium, diazinon, atrazine, and cyanide to the species Lemna Minor, Pimephales promelas, Daphnia magna, and Ceriodaphnia dubia. Observed values were used as benchmarks for assessing the se...

  10. [Evaluation of chlorine dioxide concentrations needed to effectively control contamination by Legionella spp in hospital hot water distribution systems].

    PubMed

    Fusaroli, Paolo; Ravaioli, Cinzia; Gabutti, Giovanni; Caroli, Maria; Stefanati, Armando

    2016-01-01

    This aim of the study was to identify effective levels of ClO2 for control of Legionella spp. contamination in the hot water (45-55 °C.) distribution system of a 579-bed hospital in Ravenna (Italy). Overall, 663 hot water samples were collected from the hospital's sinks and shower taps and were analyzed. Trend line analysis, which describes the trend in the number of positive samples collected according to disinfectant concentration, shows that the lowest number of positive samples was achieved with concentrations of ClO2 between 0.22 and 0, 32 mg /l.

  11. Sex-steroid and thyroid hormone concentrations in juvenile alligators (Alligator mississippiensis) from contaminated and reference lakes in Florida, USA

    USGS Publications Warehouse

    Grain, D.A.; Guillette, L.J.; Pickford, D.B.; Percival, H.F.; Woodward, A.R.

    1998-01-01

    Sex-steroid and thyroid hormones are critical regulators of growth and reproduction in all vertebrates, and several recent studies suggest that environmental chemicals can alter circulating concentrations of these hormones. This study examines plasma concentrations of estradiol-171?? (E2), testosterone (T), triiodothyronine (T3), and thyroxine (T4) in juvenile alligators (60-140 cm total length) from two contaminated lakes and one reference lake in Florida. First, the data were analyzed by comparing hormone concentrations among males and females from the different lakes. Whereas there were no differences in plasma E2 concentrations among animals of the three lakes, male alligators from the contaminated lakes (Lake Apopka and Lake Okeechobee) had significantly lower plasma T concentrations compared 10 males from the reference take (Lake Woodruff). Concentrations of thyroid hormones also differed in animals of the three lakes, with T4 concentrations being elevated in Lake Okeechobee males compared to Lake Woodruff males. Second, the relationship between body size and hormone concentration was examined using regression analysis. Most notably for steroid hormones, no clear relationship was detected between E2 and total length in Apopka females (r2 0.09, p = 0.54) or between T and total length in Apopka males (r2 = 0.007, p = 0.75). Females from Apopka (r2 = 0.318, p = 0.09) and Okeechobee (r2 = 0.222, p = 0.09) exhibited weak correlations between T3 and total length. Males from Apopka (r2 = 0.015, p = 0.66) and Okeechobee (r2 = 0.128, p = 0.19) showed no correlation between T4 and total length. These results indicate: some of the previously reported abnormalities in steroid hormones of hatchling alligators persist, at least, through the juvenile years; steroid and thyroid hormones are related to body size in juvenile alligators from the reference lake, whereas alligators living in lakes Apopka and Okeechobee experience alterations in circulating thyroid and steroid

  12. Concentrations in ambient air and emissions of cyclic volatile methylsiloxanes in Zurich, Switzerland.

    PubMed

    Buser, Andreas M; Kierkegaard, Amelie; Bogdal, Christian; MacLeod, Matthew; Scheringer, Martin; Hungerbühler, Konrad

    2013-07-02

    Tens of thousands of tonnes of cyclic volatile methylsiloxanes (cVMS) are used each year globally, which leads to high and continuous cVMS emissions to air. However, field measurements of cVMS in air and empirical information about emission rates to air are still limited. Here we present measurements of decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6) in air for Zurich, Switzerland. The measurements were performed in January and February 2011 over a period of eight days and at two sites (city center and background) with a temporal resolution of 6-12 h. Concentrations of D5 and D6 are higher in the center of Zurich and range from 100 to 650 ng m(-3) and from 10 to 79 ng m(-3), respectively. These values are among the highest levels of D5 and D6 reported in the literature. In a second step, we used a multimedia environmental fate model parametrized for the region of Zurich to interpret the levels and time trends in the cVMS concentrations and to back-calculate the emission rates of D5 and D6 from the city of Zurich. The average emission rates obtained for D5 and D6 are 120 kg d(-1) and 14 kg d(-1), respectively, which corresponds to per-capita emissions of 310 mg capita(-1) d(-1) for D5 and 36 mg capita(-1) d(-1) for D6.

  13. Transport of semivolatile organic compounds to the Tibetan plateau: spatial and temporal variation in air concentrations in mountainous Western Sichuan, China.

    PubMed

    Liu, Wenjie; Chen, Dazhou; Liu, Xiande; Zheng, Xiaoyan; Yang, Wen; Westgate, John N; Wania, Frank

    2010-03-01

    The distribution of organochlorine pesticides and polychlorinated biphenyls in air along an altitudinal transect on Balang Mountain in western China was measured by deploying XAD-2 resin based passive air samplers in duplicate at seven sites with elevations ranging from 1242 to 4485 m above sea level for five consecutive six-month periods between 2005 and 2008. Analyzed by gas chromatography-high resolution mass spectrometry, concentrations of hexachlorobenzene were highest, followed by hexachlorocyclohexanes, DDT-related compounds and PCB congeners 28 and 52. Except for hexachlorobenzene, which had largely uniform concentrations in space and time, there were clear seasonal variations with concentrations in summer being higher than in winter. With a few exceptions, concentrations that vary little with altitude suggest that the presence of these chemicals in the area is almost entirely due to atmospheric transport, most likely from the Chengdu plain. This is supported by similarities in the relative abundance of different compounds and in the differences between summer and winter concentrations measured in the city of Chengdu and in the mountains. Furthermore, air mass trajectories during the sampling period often originate to the East, passing over the Western part of the Sichuan basin, including the Chengdu plain, prior to arriving at the sampling sites. Higher summer time values in the mountains are due to more contaminated air being blown into the region, presumably due either to higher pesticide usage in summer or due to higher temperatures leading to higher evaporation in source regions. Air and soil from the region are in equilibrium with respect to alpha-HCH, gamma-HCH, and HCB, whereas a situation of net deposition prevails for p,p'-DDE and p,p'-DDT.

  14. Comparing air dispersion model predictions with measured concentrations of VOCs in urban communities.

    PubMed

    Pratt, Gregory C; Wu, Chun Yi; Bock, Don; Adgate, John L; Ramachandran, Gurumurthy; Stock, Thomas H; Morandi, Maria; Sexton, Ken

    2004-04-01

    Air concentrations of nine volatile organic compounds were measured over 48-h periods at 23 locations in three communities in the Minneapolis-St. Paul metropolitan area. Concentrations at the same times and locations were modeled using a standard regulatory air dispersion model (ISCST3). The goal of the study was to evaluate model performance by comparing predictions with measurements using linear regression and estimates of bias. The modeling, done with mobile and area source emissions resolved to the census tract level and characterized as model area sources, represents an improvement over large-scale airtoxics modeling analyses done to date. Despite the resolved spatial scale, the model did not fully capture the spatial resolution in concentrations in an area with a sharp gradient in emissions. In a census tract with a major highway at one end of the tract (i.e., uneven distribution of emissions within the tract), model predictions atthe opposite end of the tract overestimated measured concentrations. This shortcoming was seen for pollutants emitted mainly by mobile sources (benzene, ethylbenzene, toluene, and xylenes). We suggest that major highways would be better characterized as line sources. The model also failed to fully capture the temporal variability in concentrations, which was expected since the emissions inventory comprised annual average values. Based on our evaluation metrics, model performance was best for pollutants emitted mainly from mobile sources and poorest for pollutants emitted mainlyfrom area sources. Important sources of error appeared to be the source characterization (especially location) and emissions quantification. We expect that enhancements in the emissions inventory would give the greatest improvement in results. As anticipated for a Gaussian plume model, performance was dramatically better when compared to measurements that were not matched in space or time. Despite the limitations of our analysis, we found thatthe regulatory

  15. Local contamination, and not feeding preferences, explains elevated PCB concentrations in Labrador ringed seals (Pusa hispida).

    PubMed

    Brown, Tanya M; Iverson, Sara J; Fisk, Aaron T; Macdonald, Robie W; Helbing, Caren C; Reimer, Ken J

    2015-05-15

    Polychlorinated biphenyls (PCBs) in high trophic level species typically reflect the contributions of myriad sources, such that source apportionment is rarely possible. The release of PCBs by a military radar station into Saglek Bay, Labrador contaminated the local marine food web. For instance, while heavier (higher chlorinated) PCB profiles in some ringed seals (Pusa hispida) were previously attributed to this local source, differences in feeding preferences among seals could not be ruled out as a contributing factor. Herein, similar fatty acid profiles between those seals with 'local' PCB profiles and those with 'long-range' or background profiles indicate little support for the possibility that differential feeding ecologies underlay the divergent PCB profiles. Ringed seals appeared to feed predominantly on zooplankton (Mysis oculata and Themisto libellula), followed by the dusky snailfish (Liparis gibbus), arctic cod (Boreogadus saida), and shorthorn sculpin (Myoxocephalus scorpius). Principal components analysis (PCA) and PCB homolog profiles illustrated the extent of contamination of the Saglek food web, which had very different (and much heavier) PCB profiles than those food web members contaminated by 'long-range' sources. Locally contaminated prey had PCB levels that were higher (2- to 544-fold) than prey contaminated by 'long-range' sources and exceeded wildlife consumption guidelines for PCBs. The application of multivariate analyses to two distinct datasets, including PCB congeners (n=50) and fatty acids (n=65), afforded the opportunity to clearly distinguish the contribution of locally-released PCBs to a ringed seal food web from those delivered via long-ranged transport. Results from the present study strongly suggest that habitat use rather than differences in prey selection is the primary mechanism explaining the divergent PCB patterns in Labrador ringed seals.

  16. Low concentrations of contaminants in an invasive cyprinid, the rudd, in a Great Lakes Area of Concern.

    PubMed

    Kapuscinski, Kevin L; Farrell, John M; Paterson, Gordon; Wilkinson, Michael A; Skinner, Lawrence C; Richter, Wayne; Gudlewski, Anthony J

    2014-11-01

    The invasive, omnivorous rudd Scardinius erythrophthalmus is abundant in the upper Niagara River, a Great Lakes Area of Concern. Invasive species can alter trophic and contaminant pathways, but complex ontogenetic and seasonal diet shifts by rudds make it difficult to predict their chemical burdens relative to other fishes. We quantified concentrations of chemical residues in rudds and compared them to six fish species from various trophic levels. Rudds contained low concentrations of total dichlorodiphenyltrichloroethane (mean = 0.02 μg/g), Hg (mean = 0.03 μg/g), and polychlorinated biphenyls (mean = 0.06 μg/g); these concentrations were among the lowest for all species examined. Concentrations of aldrin, heptachlor, hexachlorobenzene, total hexachlorocyclohexanes, mirex, and total chlordanes were less than the method detection limit for all rudds examined. If reducing rudd biomass is determined to be beneficial, resource managers could consider targeted harvest, given the low concentrations of contaminant in rudds and their susceptibility to capture.

  17. Concentrations of organic contaminants detected during managed flow conditions, San Joaquin River and Old River, California, 2001

    USGS Publications Warehouse

    Orlando, James L.; Kuivila, Kathryn

    2005-01-01

    Concentrations of organic contaminants were determined in water samples collected at six surface-water sites located along the San Joaquin and Old Rivers during April through June 2001. Water samples were collected, coincident with salmon smolt caging studies conducted by researchers from the Bodega Marine Laboratory at the University of California at Davis to characterize exposure of the salmon smolt to organic contaminants. Sampling occurred prior to, during, and following the implementation of managed streamflow conditions on the San Joaquin and Old Rivers as part of the Vernalis Adaptive Management Plan. Thirteen pesticides were detected in water samples collected during this study, and at least five pesticides were detected in each sample. The total number of pesticide detections varied little between river systems and between sites, but the maximum concentrations of most pesticides occurred in San Joaquin River samples. The total number of pesticides detected varied little over the three time periods. However, during the period of managed streamflow, the fewest number of pesticides were detected at their absolute maximum concentration. Nine wastewater compounds were detected during this study. Suspended-sediment concentrations were similar for the San Joaquin and Old Rivers except during the period of managed streamflow conditions, when suspended-sediment concentration was higher at sites on the San Joaquin River than at sites on the Old River. Values for water parameters (pH, specific conductance, and hardness) were lowest during the period of managed flows.

  18. Particulate matter concentrations in residences: an intervention study evaluating stand-alone filters and air conditioners

    PubMed Central

    Batterman, S.; Du, L.; Mentz, G.; Mukherjee, B.; Parker, E.; Godwin, C.; Chin, J.-Y.; O'Toole, A.; Robins, T.; Rowe, Z.; Lewis, T.

    2014-01-01

    This study, a randomized controlled trial, evaluated the effectiveness of free-standing air filters and window air conditioners (ACs) in 126 low-income households of children with asthma. Households were randomized into a control group, a group receiving a free-standing HEPA filter placed in the child's sleeping area, and a group receiving the filter and a window-mounted AC. Indoor air quality (IAQ) was monitored for week-long periods over three to four seasons. High concentrations of particulate matter (PM) and carbon dioxide were frequently seen. When IAQ was monitored, filters reduced PM levels in the child's bedroom by an average of 50%. Filter use varied greatly among households and declined over time, for example, during weeks when pollutants were monitored, filter use was initially high, averaging 84 ± 27%, but dropped to 63 ± 33% in subsequent seasons. In months when households were not visited, use averaged only 34 ± 30%. Filter effectiveness did not vary in homes with central or room ACs. The study shows that measurements over multiple seasons are needed to characterize air quality and filter performance. The effectiveness of interventions using free-standing air filters depends on occupant behavior, and strategies to ensure filter use should be an integral part of interventions. PMID:22145709

  19. Natural ³⁷Ar concentrations in soil air: implications for monitoring underground nuclear explosions.

    PubMed

    Riedmann, Robin A; Purtschert, Roland

    2011-10-15

    For on-site inspections (OSI) under the Comprehensive Nuclear-Test-Ban Treaty (CTBT) measurement of the noble gas ³⁷Ar is considered an important technique. ³⁷Ar is produced underground by neutron activation of Calcium by the reaction ⁴⁰Ca(n,α)³⁷Ar. The naturally occurring equilibrium ³⁷Ar concentration balance in soil air is a function of an exponentially decreasing production rate from cosmic ray neutrons with increasing soil depth, diffusive transport in the soil air, and radioactive decay (T(1/2): 35 days). In this paper for the first time, measurements of natural ³⁷Ar activities in soil air are presented. The highest activities of ~100 mBq m⁻³ air are 2 orders of magnitude larger than in the atmosphere and are found in 1.5-2.5 m depth. At depths > 8 m ³⁷Ar activities are < 20 mBq m⁻³ air. After identifying the main ³⁷Ar production and gas transport factors the expected global activity range distribution of ³⁷Ar in shallow subsoil (0.7 m below the surface) was estimated. In high altitude soils, with large amounts of Calcium and with low gas permeability, ³⁷Ar activities may reach values up to 1 Bq m⁻³.

  20. Prevention of optics and resist contamination in 300-mm lithography: improvements in chemical air filtration

    NASA Astrophysics Data System (ADS)

    Kinkead, Devon A.; Grayfer, Anatoly; Kishkovich, Oleg P.

    2001-08-01

    Atmospheric pressure deep UV lithography using fast chemically amplified photoresists will be the mainstay of semiconductor production into the foreseeable future. Airborne molecular contamination (AMC) in the form of bases and condensable organic and inorganic materials however, threaten both sensitive optics and modern resists thereby creating a host of yield limiting contamination issues. Past work by Kunz at MIT has described photo-induced organic contamination of lithographic optics as a significant concern in leading-edge lithography. Moreover, Kinkead and Ercken, and Kishkovich and Dean have published work on the impact of base contamination on CD uniformity in modern photoresists. Herein, the authors discuss solutions to control both optics and resist contamination in a single compact filter system for advanced lithography. The results of this work suggest that resist and optics contamination can be controlled as we enter the era of low K1 factor <150nm/300mm-device production.

  1. Determination of radionuclide concentrations in ground level air using the ASS-500 high volume sampler

    SciTech Connect

    Frenzel, E.; Arnold, D.; Wershofen, H.

    1996-06-01

    A method for determination of radionuclide concentrations in air aerosol samples collected by the high volume aerosol sampler ASS-500 was elaborated. The aerosol sampling station ASS-500 is a Stand alone, all-weather proofed instrument. It is designed for representative sampling of airborne radionuclides from ground level air at a height of about 1.5 m above ground level. The ASS-500 station enables continuous air monitoring both normal and emergency Situations. The collection of aerosols on the Petrianov FPP-15-1.5 type filter out of an air volume of about 100,000 m{sup 3} (sampling period 1 wk) or of about 250,000 m{sup 3} (sampling period 3 wk) admits accurate spectrometric low level measurements of natural and artificial radionuclides. The achieved detection limit is 0.5 {mu}Bq m{sup -3} and 0.2 {mu}Bq m{sup -3} for {sup 137}Cs, respectively. A new developed air flow Meter system allows to enhance the collected air volume to about 150,000 m{sup 3} per week and lowers the detection limit to <0.4 {mu}Bq m{sup -3} for {sup 137}Cs for weekly collected aerosol samples. In Poland the CLOR uses 9 Stations ASS-500 at different sites as atmospheric radioactivity control system. On the basis of spectrometric measurements of natural and artificial radionuclides in the collected aerosol samples at the different sites, CLOR establishes a weekly report about the radiological situation at Poland for responsible authorities. The very low achievable detection limit of the Station ASS-500 due 10 the high air flow fate and the long possible sampling period were the key argument for other government radiation protection authorities in Europe to introduce the Station ASS-500 into their low level radionuclide atmospheric monitoring programs (Austria, Belarus, France, Germany, Iceland, Spain, Switzerland, Ukraine).

  2. Daily and hourly sourcing of metallic and mineral dust in urban air contaminated by traffic and coal-burning emissions

    NASA Astrophysics Data System (ADS)

    Moreno, T.; Karanasiou, A.; Amato, F.; Lucarelli, F.; Nava, S.; Calzolai, G.; Chiari, M.; Coz, E.; Artíñano, B.; Lumbreras, J.; Borge, R.; Boldo, E.; Linares, C.; Alastuey, A.; Querol, X.; Gibbons, W.

    2013-04-01

    A multi-analytical approach to chemical analysis of inhalable urban atmospheric particulate matter (PM), integrating particle induced X-ray emission, inductively coupled plasma mass spectrometry/atomic emission spectroscopy, chromatography and thermal-optical transmission methods, allows comparison between hourly (Streaker) and 24-h (High volume sampler) data and consequently improved PM chemical characterization and source identification. In a traffic hot spot monitoring site in Madrid (Spain) the hourly data reveal metallic emissions (Zn, Cu, Cr, Fe) and resuspended mineral dust (Ca, Al, Si) to be closely associated with traffic flow. These pollutants build up during the day, emphasizing evening rush hour peaks, but decrease (especially their coarser fraction PM2.5-10) after nocturnal road washing. Positive matrix factorization (PMF) analysis of a large Streaker database additionally reveals two other mineral dust components (siliceous and sodic), marine aerosol, and minor, transient events which we attribute to biomass burning (K-rich) and industrial (incinerator?) Zn, Pb plumes. Chemical data on 24-h filters allows the measurement of secondary inorganic compounds and carbon concentrations and offers PMF analysis based on a limited number of samples but using fuller range of trace elements which, in the case of Madrid, identifies the continuing minor presence of a coal combustion source traced by As, Se, Ge and Organic Carbon. This coal component is more evident in the city air after the change to the winter heating season in November. Trace element data also allow use of discrimination diagrams such as V/Rb vs. La/Ce and ternary plots to illustrate variations in atmospheric chemistry (such as the effect of Ce-emissions from catalytic converters), with Madrid being an example of a city with little industrial pollution, recently reduced coal emissions, but serious atmospheric contamination by traffic emissions.

  3. Measured concentrations of radioactive particles in air in the vicinity of the Anaconda Uranium Mill

    SciTech Connect

    Momeni, M H; Kisieleski, W E

    1980-02-01

    Concentrations of radioactive particles (U-238, Th-230, Ra-226, and Pb-210) in air were measured in the vicinity of the Anaconda Uranium Mill, Bluewater, New Mexico. Airborne particles were collected at three stations for about two-thirds of a year using a continuous collection method at a sampling rate of 10 L/min, and also were measured in monthly composites collected periodically at four stations using high volume air samplers at a sampling rate of 1400 L/min. The ratios of concentrations of each radionuclide to the concentrations of U-238 indicate that the concentrations of the radionuclides are influenced principally by the proximity of the major sources of emission and the direction of the wind. In all cases, the concentration of Pb-210 exceeded that of U-238. The ratio of Pb-210/U-238 was 12.3 and 13.3 for stations dominated by the emissions from the tailings and ore pads, but was only 1.6 for the station dominated by the yellowcake stack emission. The ratio of the radionuclide concentrations measured by the two methods of sample collection was between 0.8 and 1.2 for uranium, radium, and lead at station 104, but was 0.28 to 1.7 for thorium, radium, and lead at stations 101 and 102. The average concentrations calculated from the measurements made in this study suggest that releases from the Anaconda mill were made well within the existing limits of the maximum permissible concentrations for inhalation exposure of the general public.

  4. Tunable hybrid plasma decomposition of dilute concentrations of CC14 in air

    SciTech Connect

    Truex, M.J. ); Bromberg, L.; Cohn, D.R.; Koch, M.; Patrick, R.M.; Thomas, P. . Plasma Fusion Center)

    1993-01-01

    At the Department of Energy Hanford site, a large quantity of the industrial solvent carbon tetrachloride (CC14) was used and subsequently disposed of in leaching fields. Efforts under the Volatile Organic Compound - Arid Integrated Demonstration Program (VOC-Arid ID) are directed at vapor extraction of carbon tetrachloride from the ground and its subsequent decomposition in the contaminated humid air stream. We are developing a mobile electron-beam driven plasma reactor for versatile efficient on-site decomposition of CC14 and other VOCs in carrier gases at atmospheric pressure. The decomposition of the VOCs could result in the generation of CO[sub 2], light hydrocarbons, and reactive chlorine compounds. The latter dissolve and/or dissociate in aqueous solutions.

  5. Tunable hybrid plasma decomposition of dilute concentrations of CC14 in air

    SciTech Connect

    Truex, M.J.; Bromberg, L.; Cohn, D.R.; Koch, M.; Patrick, R.M.; Thomas, P.

    1993-01-01

    At the Department of Energy Hanford site, a large quantity of the industrial solvent carbon tetrachloride (CC14) was used and subsequently disposed of in leaching fields. Efforts under the Volatile Organic Compound - Arid Integrated Demonstration Program (VOC-Arid ID) are directed at vapor extraction of carbon tetrachloride from the ground and its subsequent decomposition in the contaminated humid air stream. We are developing a mobile electron-beam driven plasma reactor for versatile efficient on-site decomposition of CC14 and other VOCs in carrier gases at atmospheric pressure. The decomposition of the VOCs could result in the generation of CO{sub 2}, light hydrocarbons, and reactive chlorine compounds. The latter dissolve and/or dissociate in aqueous solutions.

  6. Effects of light intensity and air velocity on air temperature, water vapor pressure, and CO2 concentration inside a plant canopy under an artificial lighting condition.

    PubMed

    Kitaya, Y; Shibuya, T; Kozai, T; Kubota, C

    1998-01-01

    In order to characterize environmental variables inside a plant canopy under artificial lighting in the CELSS, we investigated the effects of light intensity and air velocity on air temperature, water vapor pressure, and CO2 concentration inside a plant canopy. Under a PPF of 500 micromoles m-2 s-1, air temperature was 2-3 degrees C higher, water vapor pressure was 0.6 kPa higher, and CO2 concentration was 25-35 micromoles mol-1 lower at heights ranging from 0 to 30 mm below the canopy than at a height 60 mm above the canopy. Increasing the PPF increased air temperature and water vapor pressure and decreased CO2 concentration inside the canopy. The air temperature was lower and the CO2 concentration was higher inside the canopy at an air velocity of 0.3 m s-1 than at an air velocity of 0.1 m s-1. The environmental variables inside the canopy under a high light intensity were characterized by higher air temperature, higher vapor pressure, and lower CO2 concentration than those outside the canopy.

  7. [Environmental investigation of ground water contamination at Wright-Patterson Air Force Base, Ohio]. Volume 5, Appendix A, Part 2, Field Investigation report

    SciTech Connect

    Not Available

    1992-03-01

    This report contains information related to the sampling and chemical analysis of ground water at the Wright-Patterson Air Force Base. It is part of a field investigation of ground water contamination.

  8. Zearalenone (ZEN) metabolism and residue concentrations in physiological specimens of dairy cows exposed long-term to ZEN-contaminated diets differing in concentrate feed proportions.

    PubMed

    Dänicke, Sven; Keese, Christina; Meyer, Ulrich; Starke, Alexander; Kinoshita, Asako; Rehage, Jürgen

    2014-12-01

    A long-term feeding experiment with dairy cows was performed to investigate the effects of feeding a Fusarium toxin contaminated (FUS) and a background-contaminated control (CON) ration with a mean concentrate feed proportion of 50% during the first 11 weeks after parturition (Groups FUS-50, CON-50, Period 1), and with concentrate feed proportions of 30% or 60% during the remaining 17 weeks (Groups CON-30, CON-60, FUS-30 and FUS-60, Period 2), on zearalenone (ZEN) residue levels in blood serum, milk, urine and bile. ZEN, α-zearalenol (α-ZEL) and β-zearalenol (β-ZEL), zearalanone (ZAL), α-zearalanol (α-ZAL) and β-zearalanol (β-ZAL) were determined by HPLC with fluorescence detection. The ZEN concentrations of the rations fed to Groups CON-50, FUS-50 (Period 1), CON-30, CON-60, FUS-30 and FUS-60 (Period 2) amounted to 53.1, 112.7, 35.0, 24.4, 73.8 and 72.5 µg/kg dry matter, respectively. The concentrations of ZEN, α-ZEL, β-ZEL, ZAN, α-ZAL and β-ZAL in serum, urine and milk were lower than 1, 1, 4, 100, 50 and 200 ng/g, respectively, while ZEN, α-ZEL and β-ZEL were detected in bile. Their levels changed with oral ZEN exposure in the course of the experiment and in a similar direction with concentrate feed proportion (Period 2 only). Thus the proportions of the individual β-ZEL, α-ZEL and ZEN concentrations of their sum varied only in narrow ranges of 68-76%, 6-13% and 12-20%, respectively. Interestingly, the bile concentrations of β-ZEL, α-ZEL and ZEN of Groups CON-60 and FUS-60 amounted to only approximately 50%, 45% and 62%, respectively, of those of Groups CON-30 and FUS-30 despite a similar or even lower ZEN exposure. The results indicate that conversion of ZEN to its detectable metabolites was not changed by different dietary concentrate feed proportions while their absolute levels were decreased. These findings might suggest concentrate feed proportion-dependent and rumen fermentation-mediated alterations in ZEN/metabolite degradation, and

  9. Air quality in postunification Erfurt, East Germany: associating changes in pollutant concentrations with changes in emissions.

    PubMed

    Ebelt, S; Brauer, M; Cyrys, J; Tuch, T; Kreyling, W G; Wichmann, H E; Heinrich, J

    2001-04-01

    The unification of East and West Germany in 1990 resulted in sharp decreases in emissions of major air pollutants. This change in air quality has provided an opportunity for a natural experiment to evaluate the health impacts of air pollution. We evaluated airborne particle size distribution and gaseous co-pollutant data collected in Erfurt, Germany, throughout the 1990s and assessed the extent to which the observed changes are associated with changes in the two major emission sources: coal burning for power production and residential heating, and motor vehicles. Continuous data for sulfur dioxide, total suspended particulates (TSP), nitric oxide, carbon monoxide, and meteorologic parameters were available for 1990-1999, and size-selective particle number and mass concentration measurements were made during winters of 1991 and 1998. We used hourly profiles of pollutants and linear regression analyses, stratified by year, weekday/weekend, and hour, using NO and SO(2) as markers of traffic- and heating-related combustion sources, respectively, to study the patterns of various particle size fractions. Supplementary data on traffic and heating-related sources were gathered to support hypotheses linking these sources with observed changes in ambient air pollution levels. Substantially decreased (19-91%) concentrations were observed for all pollutants, with the exception of particles in the 0.01-0.03 microm size range (representing the smallest ultrafine particles that were measured). The number concentration for these particles increased by 115% between 1991 and 1998. The ratio of these ultrafine particles to TSP also increased by more than 500%, indicating a dramatic change in the size distribution of airborne particles. Analysis of hourly concentration patterns indicated that in 1991, concentrations of SO(2) and larger particle sizes were related to residential heating with coal. These peaks were no longer evident in 1998 due to decreases in coal consumption and

  10. Air quality in postunification Erfurt, East Germany: associating changes in pollutant concentrations with changes in emissions.

    PubMed Central

    Ebelt, S; Brauer, M; Cyrys, J; Tuch, T; Kreyling, W G; Wichmann, H E; Heinrich, J

    2001-01-01

    The unification of East and West Germany in 1990 resulted in sharp decreases in emissions of major air pollutants. This change in air quality has provided an opportunity for a natural experiment to evaluate the health impacts of air pollution. We evaluated airborne particle size distribution and gaseous co-pollutant data collected in Erfurt, Germany, throughout the 1990s and assessed the extent to which the observed changes are associated with changes in the two major emission sources: coal burning for power production and residential heating, and motor vehicles. Continuous data for sulfur dioxide, total suspended particulates (TSP), nitric oxide, carbon monoxide, and meteorologic parameters were available for 1990-1999, and size-selective particle number and mass concentration measurements were made during winters of 1991 and 1998. We used hourly profiles of pollutants and linear regression analyses, stratified by year, weekday/weekend, and hour, using NO and SO(2) as markers of traffic- and heating-related combustion sources, respectively, to study the patterns of various particle size fractions. Supplementary data on traffic and heating-related sources were gathered to support hypotheses linking these sources with observed changes in ambient air pollution levels. Substantially decreased (19-91%) concentrations were observed for all pollutants, with the exception of particles in the 0.01-0.03 microm size range (representing the smallest ultrafine particles that were measured). The number concentration for these particles increased by 115% between 1991 and 1998. The ratio of these ultrafine particles to TSP also increased by more than 500%, indicating a dramatic change in the size distribution of airborne particles. Analysis of hourly concentration patterns indicated that in 1991, concentrations of SO(2) and larger particle sizes were related to residential heating with coal. These peaks were no longer evident in 1998 due to decreases in coal consumption and

  11. Spatial and temporal distribution of pesticide air concentrations in Canadian agricultural regions

    NASA Astrophysics Data System (ADS)

    Yao, Yuan; Tuduri, Ludovic; Harner, Tom; Blanchard, Pierrette; Waite, Don; Poissant, Laurier; Murphy, Clair; Belzer, Wayne; Aulagnier, Fabien; Li, Yi-Fan; Sverko, Ed

    The Canadian Pesticide Air Sampling Campaign was initiated in 2003 to assess atmospheric levels of pesticides, especially currently used pesticides (CUPs) in agricultural regions across Canada. In the first campaign during the spring to summer of 2003, over 40 pesticides were detected. The spatial and temporal distribution of pesticides in the Canadian atmosphere was shown to reflect the pesticide usage in each region. Several herbicides including triallate, bromoxynil, MCPA, 2,4-D, dicamba, trifluralin and ethalfluralin were detected at highest levels at Bratt's Lake, SK in the prairie region. Strong relationships between air concentrations and dry depositions were observed at this site. Although no application occurred in the Canadian Prairies in 2003, high air concentrations of lindane ( γ-hexachlorocyclohexane) were still observed at Bratt's Lake and Hafford, SK. Two fungicides (chlorothalonil and metalaxyl) and two insecticides (endosulfan and carbofuran) were measured at highest levels at Kensington, PEI. Maximum concentrations of chlorpyrifos and metolachlor were found at St. Anicet, QC. The southern Ontario site, Egbert showed highest concentration of alachlor. Malathion was detected at the highest level at the west coast site, Abbotsford, BC. In case of legacy chlorinated insecticides, high concentrations of DDT, DDE and dieldrin were detected in British Columbia while α-HCH and HCB were found to be fairly uniform across the country. Chlordane was detected in Ontario, Québec and Prince Edward Island. This study demonstrates that the sources for the observed atmospheric occurrence of pesticides include local current pesticide application, volatilization of pesticide residues from soil and atmospheric transport. In many instances, these data represent the first measurements for certain pesticides in a given part of Canada.

  12. Modeling of air pollutant concentrations in an industrial region of Turkey.

    PubMed

    Tuygun, Gizem Tuna; Altuğ, Hicran; Elbir, Tolga; Gaga, Eftade E

    2017-02-03

    The hourly SO2 and PM10 concentrations in ambient air of the Kutahya city located at the western part of Turkey have exceeded the air quality limits in winter months since several years. The region has major industrial plants including lignite-fired power plants and open-cast mining activities, residential areas, and traffic sources. To obtain and quantify the sector-wise anthropogenic emissions and spatial distribution of the major pollutants including SO2, NO x , PM10, and CO, a comprehensive emission inventory with 1-km spatial resolution was prepared for the year of 2014, and the AERMOD dispersion model was used to predict ambient air concentrations in a domain of 140 km by 110 km. Validation of the model results was also done referring to in situ routine measurements at two monitoring stations located in the study area. Total emissions of SO2, PM10, NO x , and CO in the study area were calculated as 64,399, 9770, 24,627, and 29,198 tons/year, respectively. The results showed that industrial plants were the largest sources of SO2, NO x , and PM10 emissions, while residential heating and road traffic were the most contributing sectors for CO emissions. Three major power plants in the region with total annual lignite consumption of 10 million tons per year were main sources of high SO2 concentrations, while high PM10 concentrations mainly originated from two major open-cast lignite mines. Major contributors of high NO x and CO concentrations were traffic including highways and urban streets, and residential heating with high lignite consumption in urban areas. Results of the dispersion model run with the emission inventory resulted in partially high index of agreement (0.75) with SO2 measured in the urban station within the modeled area.

  13. Integration of stable isotope and trace contaminant concentration for enhanced forensic acetone discrimination

    SciTech Connect

    Moran, James J.; Ehrhardt, Christopher J.; Wahl, Jon H.; Kreuzer, Helen W.; Wahl, Karen L.

    2013-07-18

    We analyzed 21 neat acetone samples from 15 different suppliers to demonstrate the utility of a coupled stable isotope and trace contaminant strategy for distinguishing forensically-relevant samples. By combining these two pieces of orthogonal data we could discriminate all of the acetones that were produced by the 15 different suppliers. Using stable isotope ratios alone, we were able to distinguish 9 acetone samples, while the remaining 12 fell into four clusters with highly similar signatures. Adding trace chemical contaminant information enhanced discrimination to 13 individual acetones with three residual clusters. The acetones within each cluster shared a common manufacturer and might, therefore, not be expected to be resolved. The data presented here demonstrates the power of combining orthogonal data sets to enhance sample fingerprinting and highlights the role disparate data could play in future forensic investigations.

  14. Indices of benthic community tolerance in contaminated Great Lakes sediments: Relations with sediment contaminant concentrations, sediment toxicity, and the sediment quality triad

    USGS Publications Warehouse

    Wildhaber, M.L.; Schmitt, C.J.

    1998-01-01

    We evaluated the toxic-units model developed by Wildhaber and Schmitt (1996) as a predictor of indices of mean tolerance to pollution (i.e., Lenat, 1993; Hilsenhoff, 1987) and other benthic community indices from Great Lakes sediments containing complex mixtures of environmental contaminants (e.g., polychlorinated biphenyls - PCBs, polycyclic aromatic hydrocarbons PAHs, pesticides, chlorinated dioxins, and metals). Sediment toxic units were defined as the ratio of the estimated pore-water concentration of a contaminant to its chronic toxicity as estimated by U.S. Environmental Protection Agency Ambient Water Quality Criteria (AWQC) or other applicable standard. The total hazard of a sediment to aquatic life was assessed by summing toxic units for all contaminants quantified. Among the benthic community metrics evaluated, total toxic units were most closely correlated with Lenat's (1993) and Hilsenhoff's (1987) indices of community tolerance (T(L), and T(H), respectively); toxic units accounted for 42% (T(L)) and 53% (T(H)) of variability in community tolerance as measured by Ponar grabs. In contrast, taxonomic richness and Shannon-Wiener diversity were not correlated (P > 0.05) with toxic units. Substitution of order- or family-level identifications for lowest possible (mostly genus- or species-) level identifications in the calculation of T(L) and T(H) indices weakened the relationships with toxic units. Tolerance values based on order- and family-level identifications of benthos for artificial substrate samples were more strongly correlated with toxic units than tolerance values for benthos from Ponar grabs. The ability of the toxic-units model to predict the other two components (i.e., laboratory-measured sediment toxicity and benthic community composition) of the Sediment Quality Triad (SQT) may obviate the need for the SQT in some situations.

  15. Polychaete richness and abundance enhanced in anthropogenically modified estuaries despite high concentrations of toxic contaminants.

    PubMed

    Dafforn, Katherine A; Kelaher, Brendan P; Simpson, Stuart L; Coleman, Melinda A; Hutchings, Pat A; Clark, Graeme F; Knott, Nathan A; Doblin, Martina A; Johnston, Emma L

    2013-01-01

    Ecological communities are increasingly exposed to multiple chemical and physical stressors, but distinguishing anthropogenic impacts from other environmental drivers remains challenging. Rarely are multiple stressors investigated in replicated studies over large spatial scales (>1000 kms) or supported with manipulations that are necessary to interpret ecological patterns. We measured the composition of sediment infaunal communities in relation to anthropogenic and natural stressors at multiple sites within seven estuaries. We observed increases in the richness and abundance of polychaete worms in heavily modified estuaries with severe metal contamination, but no changes in the diversity or abundance of other taxa. Estuaries in which toxic contaminants were elevated also showed evidence of organic enrichment. We hypothesised that the observed response of polychaetes was not a 'positive' response to toxic contamination or a reduction in biotic competition, but due to high levels of nutrients in heavily modified estuaries driving productivity in the water column and enriching the sediment over large spatial scales. We deployed defaunated field-collected sediments from the surveyed estuaries in a small scale experiment, but observed no effects of sediment characteristics (toxic or enriching). Furthermore, invertebrate recruitment instead reflected the low diversity and abundance observed during field surveys of this relatively 'pristine' estuary. This suggests that differences observed in the survey are not a direct consequence of sediment characteristics (even severe metal contamination) but are related to parameters that covary with estuary modification such as enhanced productivity from nutrient inputs and the diversity of the local species pool. This has implications for the interpretation of diversity measures in large-scale monitoring studies in which the observed patterns may be strongly influenced by many factors that covary with anthropogenic modification.

  16. Predicting soil fumigant air concentrations under regional and diverse agronomic conditions.

    PubMed

    Cryer, Steven A

    2005-01-01

    SOFEA (SOil Fumigant Exposure Assessment system; Dow AgroSciences, Indianapolis, IN) is a new stochastic numerical modeling tool for evaluating and managing human inhalation exposure potential associated with the use of soil fumigants. SOFEA calculates fumigant concentrations in air arising from volatility losses from treated fields for large agricultural regions using multiple transient source terms (treated fields), geographical information systems (GIS) information, agronomic specific variables, user-specified buffer zones, and field reentry intervals. A modified version of the USEPA Industrial Source Complex Short Term model (ISCST3) is used for air dispersion calculations. Weather information, field size, application date, application rate, application type, soil incorporation depth, pesticide degradation rates in air, tarp presence, field retreatment, and other sensitive parameters are varied stochastically using Monte Carlo techniques to mimic region and crop specific agronomic practices. Regional land cover, elevation, and population information can be used to refine source placement (treated fields), dispersion calculations, and risk assessments. This paper describes the technical algorithms of SOFEA and offers comparisons of simulation predictions for the soil fumigant 1,3-dichloropropene (1,3-D) to actual regional air monitoring measurements from Kern, California. Comparison of simulation results to daily air monitoring observations is remarkable over the entire concentration distribution (average percent deviation of 44% and model efficiency of 0.98), especially considering numerous inputs such as meteorological conditions for SOFEA were unavailable and approximated by neighboring regions. Both current and anticipated and/or forecasted fumigant scenarios can be simulated using SOFEA to provide risk managers and product stewards the necessary information to make sound regulatory decisions regarding the use of soil fumigants in agriculture.

  17. Local characteristics of cross-unit contamination around high-rise building due to wind effect: mean concentration and infection risk assessment.

    PubMed

    Liu, X P; Niu, J L; Kwok, K C S; Wang, J H; Li, B Z

    2011-08-15

    In this present work, the characteristics of hazardous gas dispersion and possible cross-unit contamination around a complex-shaped high-rise residential building due to wind effect are thoroughly studied using physical modeling method. Experiments were performed in a boundary layer wind tunnel for a 1:30 scale model that represented a 10-story residential building in prototype. Tracer gas, simulating exhausted room air, was continuously released from different floor levels, and its concentrations on the adjacent envelope surfaces were measured using fast flame ionization detectors. The mean concentration fields were reported and analyzed under different configurations during the experiment to consider the effects on pollutant dispersion behavior due to changes in source position and approaching wind condition, with the main emphasis on the differences between open-window and closed-window conditions. In particular, the measured concentration fields were further examined from a practical point of view, with respect to hazard assessment. Understanding these hazardous plume dispersion features is useful for employing effective intervention strategies in modern residential building environment in case of hazardous substance release. The study on this physical process is not only helpful to reduce the hazardous effect of routine release of harmful pollutant near the building, but also useful for the purpose of prevention and control of accidental infectious diseases outbreak.

  18. Benzo(a)pyrene in Europe: Ambient air concentrations, population exposure and health effects.

    PubMed

    Guerreiro, C B B; Horálek, J; de Leeuw, F; Couvidat, F

    2016-07-01

    This study estimated current benzo(a)pyrene (BaP) concentration levels, population exposure and potential health impacts of exposure to ambient air BaP in Europe. These estimates were done by combining the best available information from observations and chemical transport models through the use of spatial interpolation methods. Results show large exceedances of the European target value for BaP in 2012 over large areas, particularly in central-eastern Europe. Results also show large uncertainties in the concentration estimates in regions with a few or no measurement stations. The estimation of the population exposure to BaP concentrations and its health impacts was limited to 60% of the European population, covering only the modelled areas which met the data quality requirement for modelling of BaP concentrations set by the European directive 2004/107/EC. The population exposure estimate shows that 20% of the European population is exposed to BaP background ambient concentrations above the EU target value and only 7% live in areas with concentrations under the estimated acceptable risk level of 0.12 ng m(-3). This exposure leads to an estimated 370 lung cancer incidences per year, for the 60% of the European population included in the estimation. Emissions of BaP have increased in the last decade with the increase in emissions from household combustion of biomass. At the same time, climate mitigation policies are promoting the use of biomass burning for domestic heating. The current study shows that there is a need for more BaP measurements in areas of low measurement density, particularly where high concentrations are expected, e.g. in Romania, Bulgaria, and other Balkan states. Furthermore, this study shows that the health risk posed by PAH exposure calls for better coordination between air quality and climate mitigation policies in Europe.

  19. Criteria and methods for establishing maximum permissible concentrations of air pollution

    PubMed Central

    Rjazanov, V. A.

    1965-01-01

    The article describes experience in the USSR in establishing standards for air pollution control. The author emphasizes that health considerations must be the main criterion in deciding permissible concentrations, which constitute the “hygienic” standards ultimately to be achieved. Economic and technological reasons may dictate temporary “sanitary” standards, which modify the requirements for a limited period. “Technological” standards relate to the economic and technological consequences of air pollution and do not concern health. The maximum permissible concentrations of toxic substances used in toxicology and industrial hygiene are not sufficiently stringent for general use, and control standards are therefore based on the results of tests carried out on animals and human subjects. Tests on animals show that certain concentrations of toxic substances cause functional changes (e.g., in higher nervous activity, cholinesterase activity, and excretion of coproporphyrin) as well as a number of protective adaptational reactions. The results are used to establish maximum permissible concentrations of pollutants within a 24-hour period. Tests on human volunteers provide a basis for determining the maximum average concentrations at a given time. Reactions to odorous substances give the olfactory threshold and the level of concentration causing respiratory and visual reflexes, as well as subsensory effects such as changes in light sensitivity and in the activity of the cerebral cortex. Morbidity statistics also provide evidence of harmful pollution, but cannot serve as a basis for establishing maximum permissible concentrations, which should aim not only at preventing illness but also at avoiding pathological and adaptational reactions. PMID:14315711

  20. Nitric Oxide and Oxygen Air-Contamination Effects on Extinction Limits of Non-Premixed Hydrocarbon-Air Flames for a HIFiRE Scramjet

    NASA Technical Reports Server (NTRS)

    Pellett, Gerald L.; Dawson, Lucy C.; Vaden, Sarah N.; Wilson, Lloyd G.

    2009-01-01

    Unique nitric oxide (NO) and oxygen air-contamination effects on the extinction Flame Strength (FS) of non-premixed hydrocarbon (HC) vs. air flames are characterized for 7 gaseous HCs, using a new idealized 9.3 mm straight-tube Opposed Jet Burner (OJB) at 1 atm. FS represents a laminar strain-induced extinction limit based on cross-section-average air jet velocity, Uair, that sustains combustion of a counter jet of gaseous fuel just before extinction. Besides ethane, propane, butane, and propylene, the HCs include ethylene, methane, and a 64 mole-% ethylene / 36 % methane mixture, the writer s previously recommended gaseous surrogate fuel for HIFiRE scramjet tests. The HC vs. clean air part of the work is an extension of a May 2008 JANNAF paper that characterized surrogates for the HIFiRE project that should mimic the flameholding of reformed (thermally- or catalytically-cracked) endothermic JP-like fuels. The new FS data for 7 HCs vs. clean air are thus consolidated with the previously validated data, normalized to absolute (local) axial-input strain rates, and co-plotted on a dual kinetically dominated reactivity scale. Excellent agreement with the prior data is obtained for all 7 fuels. Detailed comparisons are also made with recently published (Univ. Va) numerical results for ethylene extinction. A 2009-revised ethylene kinetic model (Univ. Southern Cal) led to predicted limits within approx. 5 % (compared to 45 %, earlier) of this writer s 2008 (and present) ethylene FSs, and also with recent independent data (Univ. Va) obtained on a new OJB system. These +/- 5 % agreements, and a hoped-for "near-identically-performing" reduced kinetics model, would greatly enhance the capability for accurate numerical simulations of surrogate HC flameholding in scramjets. The measured air-contamination effects on normalized FS extinction limits are projected to assess ongoing Arc-Heater-induced "facility test effects" of NO production (e.g., 3 mole-%) and resultant oxygen