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Sample records for infrared excess pah

  1. The Infrared Spectra of Polycyclic Aromatic Hydrocarbons with Excess Peripheral H Atoms (H(sub n)-PAHs) and their Relation to the 3.4 and 6.9 Micrometer PAH Emission Features

    Science.gov (United States)

    Sandford, Scott A.; Bernstein, Max P.; Materese, Christopher K.

    2013-01-01

    A population of polycyclic aromatic hydrocarbons (PAHs) and related materials are thought to be responsible for the family of infrared emission features that are seen towards a wide variety of astrophysical environments. A potentially important subclass of these materials are polycyclic aromatic hydrocarbons whose edges contain excess H atoms (H(sub n)-PAHs). While it has been suggested that this type of compound may be present in the interstellar population, it has been difficult to properly assess this possibility because of a lack of suitable infrared laboratory spectra to assist with analysis of the astronomical data. We present the 4000-500 cm(exp -1) (2.5-20 micrometers) infrared spectra of 23 H(sub n)-PAHs and related molecules isolated in argon matrices, under conditions suitable for use in the interpretation of astronomical data. The spectra of molecules with mixed aromatic and aliphatic domains show unique characteristics that distinguish them from their fully aromatic PAH equivalents. We discuss the changes to the spectra of these types of molecules as they transition from fully aromatic to fully aliphatic forms. The implications for the interpretation of astronomical spectra are discussed with specific emphasis on the 3.4 and 6.9 micrometer features. Laboratory data is compared with emission spectra from IRAS 21282+5050, an object with normal PAH emission features, in addition to IRAS 22272+5435 and IRAS 0496+3429, two protoplanetary nebulae with abnormally large 3.4 micrometer features. We show that 'normal' PAH emission objects contain relatively few H(sub n)-PAHs in their emitter populations, but less evolved protoplanetary nebulae may contain significant abundances of these molecules.

  2. Infrared spectra of interstellar deuteronated PAHs

    Science.gov (United States)

    Buragohain, Mridusmita; Pathak, Amit; Sarre, Peter

    2015-08-01

    Polycyclic Aromatic Hydrocarbon (PAH) molecules have emerged as a potential constituent of the ISM that emit strong features at 3.3, 6.2, 7.7, 8.6, 11.2 and 12.7 μm with weaker and blended features in the 3-20μm region. These features are proposed to arise from the vibrational relaxation of PAH molecules on absorption of background UV photons (Tielens 2008). These IR features have been observed towards almost all types of astronomical objects; say H II regions, photodissociation regions, reflection nebulae, planetary nebulae, young star forming regions, external galaxies, etc. A recent observation has proposed that interstellar PAHs are major reservoir for interstellar deuterium (D) (Peeters et al. 2004). According to the `deuterium depletion model' as suggested by Draine (2006), some of the Ds formed in the big bang are depleted in PAHs, which can account for the present value of D/H in the ISM. Hence, study of deuterated PAHs (PADs) is essential in order to measure D/H in the ISM.In this work, we consider another probable category of the large PAH family, i.e. Deuteronated PAHs (DPAH+). Onaka et al. have proposed a D/H ratio which is an order of magnitude smaller than the proposed value of D/H by Draine suggesting that if Ds are depleted in PAHs, they might be accommodated in large PAHs (Onaka et al. 2014). This work reports a `Density Functional Theory' calculation of large deuteronated PAHs (coronene, ovalene, circumcoronene and circumcircumcoronene) to determine the expected region of emission features and to find a D/H ratio that is comparable to the observational results. We present a detailed analysis of the IR spectra of these molecules and discuss the possible astrophysical implications.ReferencesDraine B. T. 2006, in ASP Conf. Ser. 348, Proc. Astrophysics in the Far Ultraviolet: Five Years of Discovery with FUSE, ed. G. Sonneborn, H. Moos, B-G Andersson (San Francisco, CA:ASP) 58Onaka T., Mori T. I., Sakon I., Ohsawa R., Kaneda H., Okada Y., Tanaka M

  3. ON THE VIABILITY OF THE PAH MODEL AS AN EXPLANATION OF THE UNIDENTIFIED INFRARED EMISSION FEATURES

    International Nuclear Information System (INIS)

    Zhang, Yong; Kwok, Sun

    2015-01-01

    Polycyclic aromatic hydrocarbon (PAH) molecules are widely considered the preferred candidate for the carrier of the unidentified infrared emission bands observed in the interstellar medium and circumstellar envelopes. In this paper, we report the results of fitting a variety of non-PAH spectra (silicates, hydrogenated amorphous carbon, coal, and even artificial spectra) using the theoretical infrared spectra of PAHs from the NASA Ames PAH IR Spectroscopic Database. We show that these non-PAH spectra can be well fitted by PAH mixtures. This suggests that a general match between astronomical spectra and those of PAH mixtures does not necessarily provide definitive support for the PAH hypothesis

  4. THE INFRARED SPECTRA OF VERY LARGE IRREGULAR POLYCYCLIC AROMATIC HYDROCARBONS (PAHs): OBSERVATIONAL PROBES OF ASTRONOMICAL PAH GEOMETRY, SIZE, AND CHARGE

    International Nuclear Information System (INIS)

    Bauschlicher, Charles W.; Peeters, Els; Allamandola, Louis J.

    2009-01-01

    The mid-infrared (IR) spectra of six large, irregular polycyclic aromatic hydrocarbons (PAHs) with formulae (C 84 H 24 -C 120 H 36 ) have been computed using density functional theory (DFT). Trends in the dominant band positions and intensities are compared to those of large, compact PAHs as a function of geometry, size, and charge. Irregular edge moieties that are common in terrestrial PAHs, such as bay regions and rings with quartet hydrogens, are shown to be uncommon in astronomical PAHs. As for all PAHs comprised solely of C and H reported to date, mid-IR emission from irregular PAHs fails to produce a strong CC str band at 6.2 μm, the position characteristic of the important, class A astronomical PAH spectra. Earlier studies showed that inclusion of nitrogen within a PAH shifts this to 6.2 μm for PAH cations. Here we show that this band shifts to 6.3 μm in nitrogenated PAH anions, close to the position of the CC stretch in class B astronomical PAH spectra. Thus, nitrogenated PAHs may be important in all sources and the peak position of the CC stretch near 6.2 μm appears to directly reflect the PAH cation to anion ratio. Large irregular PAHs exhibit features at 7.8 μm but lack them near 8.6 μm. Hence, the 7.7 μm astronomical feature is produced by a mixture of small and large PAHs while the 8.6 μm band can only be produced by large compact PAHs. As with the CC str , the position and profile of these bands reflect the PAH cation to anion ratio.

  5. Cosmic PAHs: from infrared astronomy to laboratory astrophysics

    Science.gov (United States)

    Joblin, Christine

    2017-06-01

    Astronomers consider polycyclic aromatic hydrocarbons (PAHs) to be the smallest dust particles and they use their infrared emission features, the aromatic infrared bands (AIBs), as a diagnostic of physical conditions in regions of star formation from the small scales of protoplanetary disks to the large scales of galaxies. This topic has to face several obstacles. One is the lack of identification of specific PAH species. Another one is that the AIB features carry not only information on the chemical diversity of species but also on photophysical processes involved in the relaxation of PAHs after having been energized by the absorption of UV photons from stars. In this presentation, I will discuss how we can progress in the analysis of the observed AIB spectrum by addressing both the photophysics of isolated PAHs and the formation and evolution of these molecules in cosmic environments. This is achieved by the combination of astronomical models with detailed investigation of molecular processes. The study of these processes has stimulated the development of dedicated laboratory setups and theoretical simulations at the forefront of molecular physics. I will more specifically present the opening given by ERC Synergy project Nanocosmos and the perspectives with the coming James Webb telescope.

  6. Search for bright stars with infrared excess

    Energy Technology Data Exchange (ETDEWEB)

    Raharto, Moedji, E-mail: moedji@as.itb.ac.id [Astronomy Research Division, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia)

    2014-03-24

    Bright stars, stars with visual magnitude smaller than 6.5, can be studied using small telescope. In general, if stars are assumed as black body radiator, then the color in infrared (IR) region is usually equal to zero. Infrared data from IRAS observations at 12 and 25μm (micron) with good flux quality are used to search for bright stars (from Bright Stars Catalogues) with infrared excess. In magnitude scale, stars with IR excess is defined as stars with IR color m{sub 12}−m{sub 25}>0; where m{sub 12}−m{sub 25} = −2.5log(F{sub 12}/F{sub 25})+1.56, where F{sub 12} and F{sub 25} are flux density in Jansky at 12 and 25μm, respectively. Stars with similar spectral type are expected to have similar color. The existence of infrared excess in the same spectral type indicates the existence of circum-stellar dust, the origin of which is probably due to the remnant of pre main-sequence evolution during star formation or post AGB evolution or due to physical process such as the rotation of those stars.

  7. A COMPREHENSIVE CENSUS OF NEARBY INFRARED EXCESS STARS

    Energy Technology Data Exchange (ETDEWEB)

    Cotten, Tara H.; Song, Inseok, E-mail: tara@physast.uga.edu, E-mail: song@physast.uga.edu [Department of Physics and Astronomy, University of Georgia, Athens, GA 30602 (United States)

    2016-07-01

    The conclusion of the Wide-Field Infrared Survey Explorer ( WISE ) mission presents an opportune time to summarize the history of using excess emission in the infrared as a tracer of circumstellar material and exploit all available data for future missions such as the James Webb Space Telescope . We have compiled a catalog of infrared excess stars from peer-reviewed articles and perform an extensive search for new infrared excess stars by cross-correlating the Tycho-2 and all-sky WISE (AllWISE) catalogs. We define a significance of excess in four spectral type divisions and select stars showing greater than either 3 σ or 5 σ significance of excess in the mid- and far-infrared. Through procedures including spectral energy distribution fitting and various image analyses, each potential excess source was rigorously vetted to eliminate false positives. The infrared excess stars from the literature and the new stars found through the Tycho-2 and AllWISE cross-correlation produced nearly 500 “Prime” infrared excess stars, of which 74 are new sources of excess, and >1200 are “Reserved” stars, of which 950 are new sources of excess. The main catalog of infrared excess stars are nearby, bright, and either demonstrate excess in more than one passband or have infrared spectroscopy confirming the infrared excess. This study identifies stars that display a spectral energy distribution suggestive of a secondary or post-protoplanetary generation of dust, and they are ideal targets for future optical and infrared imaging observations. The final catalogs of stars summarize the past work using infrared excess to detect dust disks, and with the most extensive compilation of infrared excess stars (∼1750) to date, we investigate various relationships among stellar and disk parameters.

  8. Developing the Infrared PAH Emission Bands Into Calibrated Probes of Astrophysical Conditions with The NASA Ames PAH IR Spectroscopic Database

    Science.gov (United States)

    Boersma, Christiaan

    We propose to quantitatively calibrate the PAH band strength ratios that have been traditionally used as qualitative proxies of PAH properties and linking PAH observables with local astrophysical conditions, thus developing PAHs into quantitative probes of astronomical environments. This will culminate in a toolbox (calibration charts) that can be used by PAH experts and non-PAH experts alike to unlock the information hidden in PAH emission sources that are part of the Spitzer and ISO archives. Furthermore, the proposed work is critical to mine the treasure trove of information JWST will return as it will capture, for the first time, the complete mid-infrared (IR) PAH spectrum with fully resolved features, through a single aperture, and along single lines-of-sight; making it possible to fully extract the information contained in the PAH spectra. In short, the work proposed here represents a major step in enabling the astronomical PAH model to reach its full potential as a diagnostic of the physical and chemical conditions in objects spanning the Universe. Polycyclic aromatic hydrocarbons (PAHs), a common and important reservoir of accessible carbon across the Universe, play an intrinsic part in the formation of stars, planets and possibly even life itself. While most PAH spectra appear quite similar, they differ in detail and contain a wealth of untapped information. Thanks to recent advances in laboratory studies and computer-based calculations of PAH spectra, the majority of which have been made at NASA Ames, coupled with the astronomical modeling tools we have developed, we can interpret the spectral details at levels never before possible. This enables us to extract local physical conditions and track subtle changes in these conditions at levels previously impossible. Building upon the tools and paradigms developed as part of the publicly available NASA Ames PAH IR Spectroscopic Database (PAHdb; www.astrochem.org/pahdb/), the purpose of our proposed research is

  9. THE FAR-INFRARED EMISSION FROM THE Mg+-PAH SPECIES

    International Nuclear Information System (INIS)

    Bauschlicher, Charles W. Jr.; Ricca, Alessandra

    2009-01-01

    The far-infrared (FIR) spectra of several Mg + -PAH species are studied using density functional theory. The Mg + -PAH stretching mode, regardless of the polycyclic aromatic hydrocarbon (PAH) species, carries a reasonable intensity and tends to fall in a narrow range near 40 μm. Because the bands tend to fall at very similar frequencies, the average spectra of several Mg + -PAH species produce a broadband with an intensity that is about 20% of the well known C-H out-of-plane bending mode. In contrast, an average of seven large compact pure PAHs has no FIR bands that carry any significant intensity.

  10. Infrared emission from a polycyclic aromatic hydrocarbon (PAH) excited by ultraviolet laser

    International Nuclear Information System (INIS)

    Cherchneff, I.; Barker, J.R.

    1989-01-01

    The infrared fluorescence spectrum from the C-H stretch modes of vibrationally excited azulene (C10H8), a PAH was measured in the laboratory. PAHs are candidates as carriers of the unidentified infrared emission bands that are observed in many astronomical objects associated with dust and ultraviolet light. In the present experiment, gas phase azulene was excited with light from a 308 nm pulsed laser, and the infrared emission spectrum was time-resolved and wavelength-resolved. Moreover, the infrared absorption spectrum of gas phase azulene was obtained using an FTIR spectrometer. The laboratory emission spectrum resembles observed infrared emission spectra from the interstellar medium, providing support for the hypothesis that PAHs are the responsible carriers. The azulene C-H stretch emission spectrum is more asymmetric than the absorption spectrum, probably due to anharmonicity of levels higher than nu = 1. 36 refs

  11. Infrared absorption and emission characteristics of interstellar PAHs [Polycyclic Aromatic Hydrocarbon

    International Nuclear Information System (INIS)

    Allamandola, L.J.; Tielens, A.G.G.M.; Barker, J.R.

    1986-01-01

    The mid-infrared interstellar emission spectrum with features at 3050, 1610, 1300, 1150, and 885 cm -1 (3.28, 6.2, 7.7, 8.7 and 11.3 microns) is discussed in terms of the Polycyclic Aromatic Hydrocarbon (PAH) hypothesis. This hypothesis is based on the suggestive, but inconclusive comparison between the interstellar emission spectrum with the infrared absorption and Raman spectra of a few PAHs. The fundamental vibrations of PAHs and PAH-like species which determine the ir and Raman properties are discussed. Interstellar ir band emission is due to relaxation from highly vibrationally excited PAHs which have been excited by ultraviolet photons. The excitation/emission process is described in general and the ir fluorescence from one PAH, chrysene, is traced in detail. Generally, there is sufficient energy to populate several vibrational levels in each mode. Molecular vibrational potentials are anharmonic and emission from these higher levels will fall at lower frequencies and produce weak features to the red of the stronger fundamentals. This process is also described and can account for some spectroscopic details of the interstellar emission spectra previously unexplained. Analysis of the interstellar spectrum shows that PAHs containing between 20 and 30 carbon atoms are responsible for the emission. 43 refs., 11 figs

  12. Infrared absorption and emission characteristics of interstellar PAHs (Polycyclic Aromatic Hydrocarbon)

    Energy Technology Data Exchange (ETDEWEB)

    Allamandola, L.J.; Tielens, A.G.G.M.; Barker, J.R.

    1986-01-01

    The mid-infrared interstellar emission spectrum with features at 3050, 1610, 1300, 1150, and 885 cm/sup -1/ (3.28, 6.2, 7.7, 8.7 and 11.3 microns) is discussed in terms of the Polycyclic Aromatic Hydrocarbon (PAH) hypothesis. This hypothesis is based on the suggestive, but inconclusive comparison between the interstellar emission spectrum with the infrared absorption and Raman spectra of a few PAHs. The fundamental vibrations of PAHs and PAH-like species which determine the ir and Raman properties are discussed. Interstellar ir band emission is due to relaxation from highly vibrationally excited PAHs which have been excited by ultraviolet photons. The excitation/emission process is described in general and the ir fluorescence from one PAH, chrysene, is traced in detail. Generally, there is sufficient energy to populate several vibrational levels in each mode. Molecular vibrational potentials are anharmonic and emission from these higher levels will fall at lower frequencies and produce weak features to the red of the stronger fundamentals. This process is also described and can account for some spectroscopic details of the interstellar emission spectra previously unexplained. Analysis of the interstellar spectrum shows that PAHs containing between 20 and 30 carbon atoms are responsible for the emission. 43 refs., 11 figs.

  13. ON INFRARED EXCESSES ASSOCIATED WITH Li-RICH K GIANTS

    Energy Technology Data Exchange (ETDEWEB)

    Rebull, Luisa M. [Spitzer Science Center (SSC) and Infrared Science Archive (IRSA), Infrared Processing and Analysis Center - IPAC, 1200 E. California Blvd., California Institute of Technology, Pasadena, CA 91125 (United States); Carlberg, Joleen K. [NASA Goddard Space Flight Center, Code 667, Greenbelt, MD 20771 (United States); Gibbs, John C.; Cashen, Sarah; Datta, Ashwin; Hodgson, Emily; Lince, Megan [Glencoe High School, 2700 NW Glencoe Rd., Hillsboro, OR 97124 (United States); Deeb, J. Elin [Bear Creek High School, 9800 W. Dartmouth Pl., Lakewood, CO 80227 (United States); Larsen, Estefania; Altepeter, Shailyn; Bucksbee, Ethan; Clarke, Matthew [Millard South High School, 14905 Q St., Omaha, NE 68137 (United States); Black, David V., E-mail: rebull@ipac.caltech.edu [Walden School of Liberal Arts, 4230 N. University Ave., Provo, UT 84604 (United States)

    2015-10-15

    Infrared (IR) excesses around K-type red giants (RGs) have previously been discovered using Infrared Astronomy Satellite (IRAS) data, and past studies have suggested a link between RGs with overabundant Li and IR excesses, implying the ejection of circumstellar shells or disks. We revisit the question of IR excesses around RGs using higher spatial resolution IR data, primarily from the Wide-field Infrared Survey Explorer. Our goal was to elucidate the link between three unusual RG properties: fast rotation, enriched Li, and IR excess. Our sample of RGs includes those with previous IR detections, a sample with well-defined rotation and Li abundance measurements with no previous IR measurements, and a large sample of RGs asserted to be Li-rich in the literature; we have 316 targets thought to be K giants, about 40% of which we take to be Li-rich. In 24 cases with previous detections of IR excess at low spatial resolution, we believe that source confusion is playing a role, in that either (a) the source that is bright in the optical is not responsible for the IR flux, or (b) there is more than one source responsible for the IR flux as measured in IRAS. We looked for IR excesses in the remaining sources, identifying 28 that have significant IR excesses by ∼20 μm (with possible excesses for 2 additional sources). There appears to be an intriguing correlation in that the largest IR excesses are all in Li-rich K giants, though very few Li-rich K giants have IR excesses (large or small). These largest IR excesses also tend to be found in the fastest rotators. There is no correlation of IR excess with the carbon isotopic ratio, {sup 12}C/{sup 13}C. IR excesses by 20 μm, though relatively rare, are at least twice as common among our sample of Li-rich K giants. If dust shell production is a common by-product of Li enrichment mechanisms, these observations suggest that the IR excess stage is very short-lived, which is supported by theoretical calculations. Conversely, the

  14. Recent Advances in Laboratory Infrared Spectroscopy of Polycyclic Aromatic Hydrocarbons: PAHs in the Far Infrared

    Science.gov (United States)

    Mattioda, Andrew L.; Ricca, Alessandra; Tucker, Jonathan; Boersma, Christiaan; Bauschlicher, Charles, Jr.; Allamandola, Louis J.

    2010-01-01

    Over 25 years of observations and laboratory work have shown that the mid-IR spectra of a majority of astronomical sources are dominated by emission features near 3.3, 6.2, 7.7, and 11.2 microns, which originate in free polycyclic aromatic hydrocarbon (PAH) molecules. PAHs dominate the mid-IR emission from many galactic and extragalactic objects. As such, this material tracks a wide variety of astronomical processes, making this spectrum a powerful probe of the cosmos Apart from bands in the mid-IR, PAHs have bands spanning the Far-IR (FIR) and emission from these FIR features should be present in astronomical sources showing the Mid-IR PAH bands. However, with one exception, the FIR spectral characteristics are known only for a few neutral small PAHs trapped in salt pellets or oils at room temperature, data which is not relevant to astrophysics. Furthermore, since most emitting PAHs responsible for the mid-IR astronomical features are ionized, the absence of any experimental or theoretical PAH ion FIR spectra will make it impossible to correctly interpret the FIR data from these objects. In view of the upcoming Herschel space telescope mission and SOFIA's FIR airborne instrumentation, which will pioneer the FIR region, it is now urgent to obtain PAH FIR spectra. This talk will present an overview recent advances in the laboratory spectroscopy of PAHs, Highlighting the FIR spectroscopy along with some quantum calculations.

  15. VARIABILITY OF THE INFRARED EXCESS OF EXTREME DEBRIS DISKS

    International Nuclear Information System (INIS)

    Meng, Huan Y. A.; Rieke, George H.; Su, Kate Y. L.; Rujopakarn, Wiphu; Ivanov, Valentin D.; Vanzi, Leonardo

    2012-01-01

    Debris disks with extremely large infrared excesses (fractional luminosities >10 –2 ) are rare. Those with ages between 30 and 130 Myr are of interest because their evolution has progressed well beyond that of protoplanetary disks (which dissipate with a timescale of order 3 Myr), yet they represent a period when dynamical models suggest that terrestrial planet building may still be progressing through large, violent collisions that could yield large amounts of debris and large infrared excesses. For example, our Moon was formed through a violent collision of two large protoplanets during this age range. We report two disks around the solar-like stars ID8 and HD 23514 in this age range where the 24 μm infrared excesses vary on timescales of a few years, even though the stars are not variable in the optical. Variations this rapid are difficult to understand if the debris is produced by collisional cascades, as it is for most debris disks. It is possible that the debris in these two systems arises in part from condensates from silicate-rich vapor produced in a series of violent collisions among relatively large bodies. If their evolution is rapid, the rate of detection of extreme excesses would indicate that major collisions may be relatively common in this age range.

  16. Infrared Fe II lines in Eta Carinae and a possible interpretation of infrared excesses

    International Nuclear Information System (INIS)

    Thackeray, A.D.

    1978-01-01

    The identification of very strong emission lines in the near infrared spectrum of Eta Carinae with newly recognised high-level transitions of Fe II raises the possibility that the infrared excesses of hot emission-line stars may be due to dielectronic recombination of Fe II. Johansson's Fe II lines also need to be considered in the interpretation of the infrared spectra of supernovae. (author)

  17. Occurrence of nitro- and oxy-PAHs in agricultural soils in eastern China and excess lifetime cancer risks from human exposure through soil ingestion.

    Science.gov (United States)

    Sun, Zhe; Zhu, Ying; Zhuo, Shaojie; Liu, Weiping; Zeng, Eddy Y; Wang, Xilong; Xing, Baoshan; Tao, Shu

    2017-11-01

    The quality of agricultural soil is vital to human health, however soil contamination is a severe problem in China. Polycyclic aromatic hydrocarbons (PAHs) have been found to be among the major soil contaminants in China. PAH derivatives could be more toxic but their measurements in soils are extremely limited. This study reports levels, spatial distributions and compositions of 11 nitrated (nPAHs) and 4 oxygenated PAHs (oPAHs) in agricultural soils covering 26 provinces in eastern China to fill the data gap. The excess lifetime cancer risk (ELCR) from the exposure to them in addition to 21 parent PAHs (pPAHs) via soil ingestion has been estimated. The mean concentration of ∑nPAHs and ∑oPAHs in agricultural soils is 50±45μg/kg and 9±8μg/kg respectively. Both ∑nPAHs and ∑oPAHs follow a similar spatial distribution pattern with elevated concentrations found in Liaoning, Shanxi, Henan and Guizhou. However if taking account of pPAHs, the high ELCR by soil ingestion is estimated for Shanxi, Zhejiang, Liaoning, Jiangsu and Hubei. The maximum ELCR is estimated at ca.10 -5 by both deterministic and probabilistic studies with moderate toxic equivalent factors (TEFs). If maximum TEFs available are applied, there is a 0.2% probability that the ELCR will exceed 10 -4 in the areas covered. There is a great chance to underestimate the ELCR via soil ingestion for some regions if only the 16 priority PAHs in agricultural soils are considered. The early life exposure and burden are considered extremely important to ELCR. Emission sources are qualitatively predicted and for areas with higher ELCR such as Shanxi and Liaoning, new loadings of PAHs and derivatives are identified. This is the first large scale study on nPAHs and oPAHs contamination levels in agricultural soils in China. The risk assessment based on this underpins the policy making and is valuable for both scientists and policy makers. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Single photon infrared emission spectroscopy: a study of IR emission from UV laser excited PAHs between 3 and 15 micrometers

    Science.gov (United States)

    Cook, D. J.; Schlemmer, S.; Balucani, N.; Wagner, D. R.; Harrison, J. A.; Steiner, B.; Saykally, R. J.

    1998-01-01

    Single-photon infrared emission spectroscopy (SPIRES) has been used to measure emission spectra from polycyclic aromatic hydrocarbons (PAHs). A supersonic free-jet expansion has been used to provide emission spectra of rotationally cold and vibrationally excited naphthalene and benzene. Under these conditions, the observed width of the 3.3-micrometers (C-H stretch) band resembles the bandwidths observed in experiments in which emission is observed from naphthalene with higher rotational energy. To obtain complete coverage of IR wavelengths relevant to the unidentified infrared bands (UIRs), UV laser-induced desorption was used to generate gas-phase highly excited PAHs. Lorentzian band shapes were convoluted with the monochromator-slit function in order to determine the widths of PAH emission bands under astrophysically relevant conditions. Bandwidths were also extracted from bands consisting of multiple normal modes blended together. These parameters are grouped according to the functional groups mostly involved in the vibration, and mean bandwidths are obtained. These bandwidths are larger than the widths of the corresponding UIR bands. However, when the comparison is limited to the largest PAHs studied, the bandwidths are slightly smaller than the corresponding UIR bands. These parameters can be used to model emission spectra from PAH cations and cations of larger PAHs, which are better candidate carriers of the UIRs.

  19. V819 TAU: A RARE WEAK-LINED T TAURI STAR WITH A WEAK INFRARED EXCESS

    International Nuclear Information System (INIS)

    Furlan, E.; Forrest, W. J.; Manoj, P.; Kim, K. H.; Watson, Dan M.; Sargent, B. A.

    2009-01-01

    We use Spitzer data to infer that the small infrared excess of V819 Tau, a weak-lined T Tauri star in Taurus, is real and not attributable to a 'companion' 10'' to the south. We do not confirm the mid-infrared excess in HBC 427 and V410 X-ray 3, which are also non-accreting T Tauri stars in the same region; instead, for the former object, the excess arises from a red companion 9'' to the east. A single-temperature blackbody fit to the continuum excess of V819 Tau implies a dust temperature of 143 K; however, a better fit is achieved when the weak 10 and 20 μm silicate emission features are also included. We infer a disk of sub-μm silicate grains between about 1 AU and several 100 AU with a constant surface density distribution. The mid-infrared excess of V819 Tau can be successfully modeled with dust composed mostly of small amorphous olivine grains at a temperature of 85 K, and most of the excess emission is optically thin. The disk could still be primordial, but gas-poor and therefore short-lived, or already at the debris disk stage, which would make it one of the youngest debris disk systems known.

  20. On the Incidence of Wise Infrared Excess Among Solar Analog, Twin, and Sibling Stars

    Energy Technology Data Exchange (ETDEWEB)

    Da Costa, A. D.; Martins, B. L. Canto; Lima Jr, J. E.; Silva, D. Freire da; Medeiros, J. R. De [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, Campus Universitário, Natal, RN, 59072-970 (Brazil); Leão, I. C. [European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching (Germany); Freitas, D. B. de, E-mail: dgerson@fisica.ufrn.br [Departamento de Física, Universidade Federal do Ceará, Caixa Postal 6030, Campus do Pici, 60455-900, Fortaleza, Ceará (Brazil)

    2017-03-01

    This study presents a search for infrared (IR) excess in the 3.4, 4.6, 12, and 22 μ m bands in a sample of 216 targets, composed of solar sibling, twin, and analog stars observed by the Wide-field Infrared Survey Explorer ( WISE ) mission. In general, an IR excess suggests the existence of warm dust around a star. We detected 12 μ m and/or 22 μ m excesses at the 3 σ level of confidence in five solar analog stars, corresponding to a frequency of 4.1% of the entire sample of solar analogs analyzed, and in one out of 29 solar sibling candidates, confirming previous studies. The estimation of the dust properties shows that the sources with IR excesses possess circumstellar material with temperatures that, within the uncertainties, are similar to that of the material found in the asteroid belt in our solar system. No photospheric flux excess was identified at the W1 (3.4 μ m) and W2 (4.6 μ m) WISE bands, indicating that, in the majority of stars of the present sample, no detectable dust is generated. Interestingly, among the 60 solar twin stars analyzed in this work, no WISE photospheric flux excess was detected. However, a null-detection excess does not necessarily indicate the absence of dust around a star because different causes, including dynamic processes and instrument limitations, can mask its presence.

  1. The WIRED Survey. 2; Infrared Excesses in the SDSS DR7 White Dwarf Catalog

    Science.gov (United States)

    Debes, John H.; Hoard, D. W.; Wachter, Stefanie; Leisawitz, David T.; Cohen, Martin

    2011-01-01

    With the launch of the Wide-field Infrar.ed Survey Explorer (WISE), a new era of detecting planetary debris and brown dwarfs (BDs) around white dwarfs (WDs) has begun with the WISE InfraRed Excesses around Degenerates (WIRED) Survey. The WIRED Survey is sensitive to substellar objects and dusty debris around WDs out to distances exceeding 100 pc, well beyond the completeness level of local WDs. In this paper, we present a cross-correlation of the preliminary Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7) WD catalog between the WISE, Two-Micron All Sky Survey (2MASS), UKIRT Infrared Deep Sky Survey (UKIDSS), and SDSS DR7 photometric catalogs. From -18,000 input targets, there are WISE detections comprising 344 "naked" WDs (detection of the WD photosphere only), 1020 candidate WD+M dwarf binaries, 42 candidate WD+BD systems, 52 candidate WD+dust disk systems, and 69 targets with indeterminate infrared excess. We classified all of the detected targets through spectral energy distribution model fitting of the merged optical, near-IR, and WISE photometry. Some of these detections could be the result of contaminating sources within the large (approx. 6") WISE point-spread function; we make a preliminary estimate for the rates of contamination for our WD+BD and WD+disk candidates and provide notes for each target of interest. Each candidate presented here should be confirmed with higher angular resolution infrared imaging or infrared spectroscopy. We also present an overview of the observational characteristics of the detected WDs in the WISE photometric bands, including the relative frequencies of candidate WD+M, WD+BD, and WD+disk systems.

  2. The periodicities in the infrared excess of G29-38 - An oscillating brown dwarf?

    International Nuclear Information System (INIS)

    Marley, M.S.; Lunine, J.I.; Hubbard, W.B.

    1990-01-01

    The oscillatory behavior of brown dwarfs has been investigated. The observed periodicities in the infrared excess of the white dwarf Giclas 29-38 are consistent with low-degree, intermediate radial order p-mode oscillations of a brown dwarf companion to the white dwarf. These oscillation modes have the correct frequencies, act on observable layers of the atmosphere, and may be excited to sufficient amplitudes to explain the observations. 14 refs

  3. How Dusty Is Alpha Centauri? Excess or Non-excess over the Infrared Photospheres of Main-sequence Stars

    Science.gov (United States)

    Wiegert, J.; Liseau, R.; Thebault, P.; Olofsson, G.; Mora, A.; Bryden, G.; Marshall, J. P.; Eiroa, C.; Montesinos, B.; Ardila, D.; hide

    2014-01-01

    Context. Debris discs around main-sequence stars indicate the presence of larger rocky bodies. The components of the nearby, solar-type binary Centauri have metallicities that are higher than solar, which is thought to promote giant planet formation. Aims. We aim to determine the level of emission from debris around the stars in the Cen system. This requires knowledge of their photospheres.Having already detected the temperature minimum, Tmin, of CenA at far-infrared wavelengths, we here attempt to do the same for the moreactive companion Cen B. Using the Cen stars as templates, we study the possible eects that Tmin may have on the detectability of unresolveddust discs around other stars. Methods.We used Herschel-PACS, Herschel-SPIRE, and APEX-LABOCA photometry to determine the stellar spectral energy distributions in thefar infrared and submillimetre. In addition, we used APEX-SHeFI observations for spectral line mapping to study the complex background around Cen seen in the photometric images. Models of stellar atmospheres and of particulate discs, based on particle simulations and in conjunctionwith radiative transfer calculations, were used to estimate the amount of debris around these stars. Results. For solar-type stars more distant than Cen, a fractional dust luminosity fd LdustLstar 2 107 could account for SEDs that do not exhibit the Tmin eect. This is comparable to estimates of fd for the Edgeworth-Kuiper belt of the solar system. In contrast to the far infrared,slight excesses at the 2:5 level are observed at 24 m for both CenA and B, which, if interpreted as due to zodiacal-type dust emission, wouldcorrespond to fd (13) 105, i.e. some 102 times that of the local zodiacal cloud. Assuming simple power-law size distributions of the dustgrains, dynamical disc modelling leads to rough mass estimates of the putative Zodi belts around the Cen stars, viz.4106 M$ of 4 to 1000 msize grains, distributed according to n(a) a3:5. Similarly, for filled-in Tmin

  4. EFFICIENT SELECTION AND CLASSIFICATION OF INFRARED EXCESS EMISSION STARS BASED ON AKARI AND 2MASS DATA

    Energy Technology Data Exchange (ETDEWEB)

    Huang Yafang; Li Jinzeng [National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100012 (China); Rector, Travis A. [University of Alaska, 3211 Providence Drive, Anchorage, AK 99508 (United States); Mallamaci, Carlos C., E-mail: ljz@nao.cas.cn [Observatorio Astronomico Felix Aguilar, Universidad Nacional de San Juan (Argentina)

    2013-05-15

    The selection of young stellar objects (YSOs) based on excess emission in the infrared is easily contaminated by post-main-sequence stars and various types of emission line stars with similar properties. We define in this paper stringent criteria for an efficient selection and classification of stellar sources with infrared excess emission based on combined Two Micron All Sky Survey (2MASS) and AKARI colors. First of all, bright dwarfs and giants with known spectral types were selected from the Hipparcos Catalogue and cross-identified with the 2MASS and AKARI Point Source Catalogues to produce the main-sequence and the post-main-sequence tracks, which appear as expected as tight tracks with very small dispersion. However, several of the main-sequence stars indicate excess emission in the color space. Further investigations based on the SIMBAD data help to clarify their nature as classical Be stars, which are found to be located in a well isolated region on each of the color-color (C-C) diagrams. Several kinds of contaminants were then removed based on their distribution in the C-C diagrams. A test sample of Herbig Ae/Be stars and classical T Tauri stars were cross-identified with the 2MASS and AKARI catalogs to define the loci of YSOs with different masses on the C-C diagrams. Well classified Class I and Class II sources were taken as a second test sample to discriminate between various types of YSOs at possibly different evolutionary stages. This helped to define the loci of different types of YSOs and a set of criteria for selecting YSOs based on their colors in the near- and mid-infrared. Candidate YSOs toward IC 1396 indicating excess emission in the near-infrared were employed to verify the validity of the new source selection criteria defined based on C-C diagrams compiled with the 2MASS and AKARI data. Optical spectroscopy and spectral energy distributions of the IC 1396 sample yield a clear identification of the YSOs and further confirm the criteria defined

  5. EFFICIENT SELECTION AND CLASSIFICATION OF INFRARED EXCESS EMISSION STARS BASED ON AKARI AND 2MASS DATA

    International Nuclear Information System (INIS)

    Huang Yafang; Li Jinzeng; Rector, Travis A.; Mallamaci, Carlos C.

    2013-01-01

    The selection of young stellar objects (YSOs) based on excess emission in the infrared is easily contaminated by post-main-sequence stars and various types of emission line stars with similar properties. We define in this paper stringent criteria for an efficient selection and classification of stellar sources with infrared excess emission based on combined Two Micron All Sky Survey (2MASS) and AKARI colors. First of all, bright dwarfs and giants with known spectral types were selected from the Hipparcos Catalogue and cross-identified with the 2MASS and AKARI Point Source Catalogues to produce the main-sequence and the post-main-sequence tracks, which appear as expected as tight tracks with very small dispersion. However, several of the main-sequence stars indicate excess emission in the color space. Further investigations based on the SIMBAD data help to clarify their nature as classical Be stars, which are found to be located in a well isolated region on each of the color-color (C-C) diagrams. Several kinds of contaminants were then removed based on their distribution in the C-C diagrams. A test sample of Herbig Ae/Be stars and classical T Tauri stars were cross-identified with the 2MASS and AKARI catalogs to define the loci of YSOs with different masses on the C-C diagrams. Well classified Class I and Class II sources were taken as a second test sample to discriminate between various types of YSOs at possibly different evolutionary stages. This helped to define the loci of different types of YSOs and a set of criteria for selecting YSOs based on their colors in the near- and mid-infrared. Candidate YSOs toward IC 1396 indicating excess emission in the near-infrared were employed to verify the validity of the new source selection criteria defined based on C-C diagrams compiled with the 2MASS and AKARI data. Optical spectroscopy and spectral energy distributions of the IC 1396 sample yield a clear identification of the YSOs and further confirm the criteria defined

  6. Low-mass Stars with Extreme Mid-Infrared Excesses: Potential Signatures of Planetary Collisions

    Science.gov (United States)

    Theissen, Christopher; West, Andrew

    2018-01-01

    I investigate the occurrence of extreme mid-infrared (MIR) excesses, a tracer of large amounts of dust orbiting stars, in low-mass stellar systems. Extreme MIR excesses, defined as an excess IR luminosity greater than 1% of the stellar luminosity (LIR/L* ≥ 0.01), have previously only been observed around a small number of solar-mass (M⊙) stars. The origin of this excess has been hypothesized to be massive amounts of orbiting dust, created by collisions between terrestrial planets or large planetesimals. Until recently, there was a dearth of low-mass (M* ≤ 0.6M⊙) stars exhibiting extreme MIR excesses, even though low-mass stars are ubiquitous (~70% of all stars), and known to host multiple terrestrial planets (≥ 3 planets per star).I combine the spectroscopic sample of low-mass stars from the Sloan Digital Sky Survey (SDSS) Data Release 7 (70,841 stars) with MIR photometry from the Wide-field Infrared Survey Explorer (WISE), to locate stars exhibiting extreme MIR excesses. I find the occurrence frequency of low-mass field stars (stars with ages ≥ 1 Gyr) exhibiting extreme MIR excesses is much larger than that for higher-mass field stars (0.41 ± 0.03% versus 0.00067 ± 0.00033%, respectively).In addition, I build a larger sample of low-mass stars based on stellar colors and proper motions using SDSS, WISE, and the Two-Micron All-Sky Survey (8,735,004 stars). I also build a galactic model to simulate stellar counts and kinematics to estimate the number of stars missing from my sample. I perform a larger, more complete study of low-mass stars exhibiting extreme MIR excesses, and find a lower occurrence frequency (0.020 ± 0.001%) than found in the spectroscopic sample but that is still orders of magnitude larger than that for higher-mass stars. I find a slight trend for redder stars (lower-mass stars) to exhibit a higher occurrence frequency of extreme MIR excesses, as well as a lower frequency with increased stellar age. These samples probe important

  7. IPHAS A-TYPE STARS WITH MID-INFRARED EXCESSES IN SPITZER SURVEYS

    International Nuclear Information System (INIS)

    Hales, Antonio S.; Barlow, Michael J.; Drew, Janet E.; Unruh, Yvonne C.; Greimel, Robert; Irwin, Michael J.; Gonzalez-Solares, Eduardo

    2009-01-01

    We have identified 17 A-type stars in the Galactic Plane that have mid-infrared (mid-IR) excesses at 8 μm. From observed colors in the (r' - Hα) - (r' - i') plane, we first identified 23,050 early A-type main-sequence (MS) star candidates in the Isaac Newton Photometric H-Alpha Survey (IPHAS) point source database that are located in Spitzer Galactic Legacy Mid-Plane Survey Extraordinaire Galactic plane fields. Imposing the requirement that they be detected in all seven Two Micron All Sky Survey and Infrared Astronomical Satellite bands led to a sample of 2692 candidate A-type stars with fully sampled 0.6 to 8 μm spectral energy distributions (SEDs). Optical classification spectra of 18 of the IPHAS candidate A-type MS stars showed that all but one could be well fitted using MS A-type templates, with the other being an A-type supergiant. Out of the 2692 A-type candidates 17 (0.6%) were found to have 8 μm excesses above the expected photospheric values. Taking into account non-A-Type contamination estimates, the 8 μm excess fraction is adjusted to ∼0.7%. The distances to these sources range from 0.7 to 2.5 kpc. Only 10 out of the 17 excess stars had been covered by Spitzer MIPSGAL survey fields, of which five had detectable excesses at 24 μm. For sources with excesses detected in at least two mid-IR wavelength bands, blackbody fits to the excess SEDs yielded temperatures ranging from 270 to 650 K, and bolometric luminosity ratios L IR /L * from 2.2 x 10 -3 - 1.9 x 10 -2 , with a mean value of 7.9 x 10 -3 (these bolometric luminosities are lower limits as cold dust is not detectable by this survey). Both the presence of mid-IR excesses and the derived bolometric luminosity ratios are consistent with many of these systems being in the planet-building transition phase between the early protoplanetary disk phase and the later debris disk phase.

  8. THE MID-INFRARED AND NEAR-ULTRAVIOLET EXCESS EMISSIONS OF QUIESCENT GALAXIES ON THE RED SEQUENCE

    International Nuclear Information System (INIS)

    Ko, Jongwan; Lee, Jong Chul; Hwang, Ho Seong; Sohn, Young-Jong

    2013-01-01

    We study the mid-infrared (IR) and near-ultraviolet (UV) excess emissions of spectroscopically selected quiescent galaxies on the optical red sequence. We use the Wide-field Infrared Survey Explorer mid-IR and Galaxy Evolution Explorer near-UV data for a spectroscopic sample of galaxies in the Sloan Digital Sky Survey Data Release 7 to study the possible connection between quiescent red-sequence galaxies with and without mid-IR/near-UV excess. Among 648 12 μm detected quiescent red-sequence galaxies without Hα emission, 26% and 55% show near-UV and mid-IR excess emissions, respectively. When we consider only bright (M r n 4000 than those without mid-IR and near-UV excess emissions. We also find that mid-IR weighted mean stellar ages of quiescent red-sequence galaxies with mid-IR excess are larger than those with near-UV excess, and smaller than those without mid-IR and near-UV excess. The environmental dependence of the fraction of quiescent red-sequence galaxies with mid-IR and near-UV excess seems strong even though the trends of quiescent red-sequence galaxies with near-UV excess differ from those with mid-IR excess. These results indicate that the recent star formation traced by near-UV (∼< 1 Gyr) and mid-IR (∼< 2 Gyr) excess is not negligible among nearby, quiescent, red, early-type galaxies. We suggest a possible evolutionary scenario of quiescent red-sequence galaxies from quiescent red-sequence galaxies with near-UV excess to those with mid-IR excess to those without near-UV and mid-IR excess.

  9. The VISTA Carina Nebula Survey. II. Spatial distribution of the infrared-excess-selected young stellar population

    Science.gov (United States)

    Zeidler, P.; Preibisch, T.; Ratzka, T.; Roccatagliata, V.; Petr-Gotzens, M. G.

    2016-01-01

    We performed a deep wide-field (6.76 sq. deg) near-infrared survey with the VISTA telescope that covers the entire extent of the Carina nebula complex (CNC). The point-source catalog created from these data contains around four million individual objects down to masses of 0.1 M⊙. We present a statistical study of the large-scale spatial distribution and an investigation of the clustering properties of infrared-excesses objects, which are used to trace disk-bearing young stellar objects (YSOs). A selection based on a near-infrared (J-H) versus (H-Ks) color-color diagram shows an almost uniform distribution over the entire observed area. We interpret this as a result of the very high degree of background contamination that arises from the Carina Nebula's location close to the Galactic plane. Complementing the VISTA near-infrared catalog with Spitzer IRAC mid-infrared photometry improves the situation of the background contamination considerably. We find that a (J-H) versus (Ks- [4.5]) color-color diagram is well suited to tracing the population of YSO-candidates (cYSOs) by their infrared excess. We identify 8781 sources with strong infrared excess, which we consider as cYSOs. This sample is used to investigate the spatial distribution of the cYSOs with a nearest-neighbor analysis. The surface density distribution of cYSOs agrees well with the shape of the clouds as seen in our Herschel far-infrared survey. The strong decline in the surface density of excess sources outside the area of the clouds supports the hypothesis that our excess-selected sample consists predominantly of cYSOs with a low level of background contamination. This analysis allows us to identify 14 groups of cYSOs outside the central area.Our results suggest that the total population of cYSOs in the CNC comprises about 164 000 objects, with a substantial fraction (~35%) located in the northern, still not well studied parts. Our cluster analysis suggests that roughly half of the cYSOs constitute a

  10. A RESOLVED MAP OF THE INFRARED EXCESS IN A LYMAN BREAK GALAXY AT z = 3

    Energy Technology Data Exchange (ETDEWEB)

    Koprowski, M. P.; Coppin, K. E. K.; Geach, J. E.; Hine, N. K.; Smith, D. J. B.; Violino, G. [Centre for Astrophysics Research, University of Hertfordshire, College Lane, Hatfield AL10 9AB (United Kingdom); Bremer, M. [H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Chapman, S. [Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS B3H 4R2 (Canada); Davies, L. J. M. [ICRAR, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009 (Australia); Hayashino, T. [Research Center for Neutrino Science, Graduate School of Science, Tohoku University, Sendai, Miyagi 980-8578 (Japan); Knudsen, K. K. [Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, SE-43992 Onsala (Sweden); Kubo, M.; Matsuda, Y. [National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka, Tokyo 181-8588 (Japan); Lehmer, B. D. [Department of Physics, University of Arkansas, 226 Physics Building, 835 West Dickson Street, Fayetteville, AR 72701 (United States); Van der Werf, P. P. [Leiden Observatory, Leiden University, P.O. Box 9513, NL-2300 RA Leiden (Netherlands); Yamada, T. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, 252-5210 Sagamihara, Kanagawa 252-5210 (Japan)

    2016-09-10

    We have observed the dust continuum of 10 z = 3.1 Lyman break galaxies with the Atacama Large Millimeter/submillimeter Array at ∼450 mas resolution in Band 7. We detect and resolve the 870 μ m emission in one of the targets with a flux density of S {sub 870} = 192 ± 57 μ Jy, and measure a stacked 3 σ signal of S {sub 870} = 67 ± 23 μ Jy for the remaining nine. The total infrared luminosities are L {sub 8–1000} = (8.4 ± 2.3) × 10{sup 10} L {sub ⊙} for the detection and L {sub 8–1000} = (2.9 ± 0.9) × 10{sup 10} L {sub ⊙} for the stack. With Hubble Space Telescope Advanced Camera for Surveys I -band imaging we map the rest-frame UV emission on the same scale as the dust, effectively resolving the “infrared excess” (IRX = L {sub FIR}/ L {sub UV}) in a normal galaxy at z = 3. Integrated over the galaxy we measure IRX = 0.56 ± 0.15, and the galaxy-averaged UV slope is β = −1.25 ± 0.03. This puts the galaxy a factor of ∼10 below the IRX– β relation for local starburst nuclei of Meurer et al. However, IRX varies by more than a factor of 3 across the galaxy, and we conclude that the complex relative morphology of the dust relative to UV emission is largely responsible for the scatter in the IRX– β relation at high- z . A naive application of a Meurer-like dust correction based on the UV slope would dramatically overestimate the total star formation rate, and our results support growing evidence that when integrated over the galaxy, the typical conditions in high- z star-forming galaxies are not analogous to those in the local starburst nuclei used to establish the Meurer relation.

  11. The excess infrared emission of Herbig Ae/Be stars - Disks or envelopes?

    Science.gov (United States)

    Hartmann, Lee; Kenyon, Scott J.; Calvet, Nuria

    1993-01-01

    It is suggested that the near-IR emission in many Herbig Ae/Be stars arises in surrounding dusty envelopes, rather than circumstellar disks. It is shown that disks around Ae/Be stars are likely to remain optically thick at the required accretion rates. It is proposed that the IR excesses of many Ae/Be stars originate in surrounding dust nebulae instead of circumstellar disks. It is suggested that the near-IR emission of the envelope is enhanced by the same processes that produce anomalous strong continuum emission at temperatures of about 1000 K in reflection nebulae surrounding hot stars. This near-IR emission could be due to small grains transiently heated by UV photons. The dust envelopes could be associated with the primary star or a nearby companion star. Some Ae/Be stars show evidence for the 3.3-6.3-micron emission features seen in reflection nebulae around hot stars, which lends further support to this suggestion.

  12. PAH EMISSION AT THE BRIGHT LOCATIONS OF PDRs: THE grandPAH HYPOTHESIS

    International Nuclear Information System (INIS)

    Andrews, H.; Tielens, A. G. G. M.; Boersma, C.; Allamandola, L. J.; Werner, M. W.; Livingston, J.

    2015-01-01

    The polycyclic aromatic hydrocarbon (PAH) emission observed in the Spitzer Infrared Spectrograph spectra of bright mid-IR locations of NGC 7023, NGC 2023, and NGC 1333 was analyzed. These objects show large variations in PAH band ratios when studied through spectral mapping. Nevertheless, the mid-IR spectra at these bright spots show a remarkably similar PAH emission. We used the NASA Ames PAH IR Spectroscopic Database to fit the observations and analyze the derived PAH populations. Our results show that PAH emission in the 5–15 μm range appears to be rather insensitive to variations of the radiation field. Similar PAH populations of neutral small to medium-sized PAHs (∼50%), with ionized species contributing in slightly less than 50%, provide very good fits. Analyzing the degeneracy of the results shows that subtle (but intrinsic) variations in the emission properties of individual PAHs lead to observable differences in the resulting spectra. On top of this, we found that variations of <30% in the PAH abundances would lead to noticeable spectral differences between the three photodissociation regions (PDRs). Therefore, PAH populations must be remarkably similar at these different lines of sight. To account for this, we suggest the concept of grandPAHs as a unique mixture of the most stable PAHs emitting at these spots. Using NGC 7023 as an example, the grandPAHs refer to the robust PAH population that results from the intense processing of PAHs at the border limit between the PDR and the molecular cloud, where, due to the UV radiation that destroys the PAH population, the abundance of PAHs starts decreasing as we move toward the star

  13. PAH EMISSION AT THE BRIGHT LOCATIONS OF PDRs: THE grandPAH HYPOTHESIS

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, H.; Tielens, A. G. G. M. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Boersma, C.; Allamandola, L. J. [NASA Ames Research Center, MS 245-6, Moffett Field, CA 94035 (United States); Werner, M. W.; Livingston, J., E-mail: heandrew@strw.leidenuniv.nl, E-mail: Christiaan.Boersma@nasa.gov [Jet Propulsion Laboratory, MC 264-767, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)

    2015-07-01

    The polycyclic aromatic hydrocarbon (PAH) emission observed in the Spitzer Infrared Spectrograph spectra of bright mid-IR locations of NGC 7023, NGC 2023, and NGC 1333 was analyzed. These objects show large variations in PAH band ratios when studied through spectral mapping. Nevertheless, the mid-IR spectra at these bright spots show a remarkably similar PAH emission. We used the NASA Ames PAH IR Spectroscopic Database to fit the observations and analyze the derived PAH populations. Our results show that PAH emission in the 5–15 μm range appears to be rather insensitive to variations of the radiation field. Similar PAH populations of neutral small to medium-sized PAHs (∼50%), with ionized species contributing in slightly less than 50%, provide very good fits. Analyzing the degeneracy of the results shows that subtle (but intrinsic) variations in the emission properties of individual PAHs lead to observable differences in the resulting spectra. On top of this, we found that variations of <30% in the PAH abundances would lead to noticeable spectral differences between the three photodissociation regions (PDRs). Therefore, PAH populations must be remarkably similar at these different lines of sight. To account for this, we suggest the concept of grandPAHs as a unique mixture of the most stable PAHs emitting at these spots. Using NGC 7023 as an example, the grandPAHs refer to the robust PAH population that results from the intense processing of PAHs at the border limit between the PDR and the molecular cloud, where, due to the UV radiation that destroys the PAH population, the abundance of PAHs starts decreasing as we move toward the star.

  14. Spectrum of excess partial molar absorptivity. Part II: a near infrared spectroscopic study of aqueous Na-halides.

    Science.gov (United States)

    Sebe, Fumie; Nishikawa, Keiko; Koga, Yoshikata

    2012-04-07

    Our earlier thermodynamic studies suggested that F(-) and Cl(-) form hydration shells with the hydration number 14 ± 2 and 2.3 ± 0.6, respectively, and leave the bulk H(2)O away from hydration shells unperturbed. Br(-) and I(-), on the other hand, form hydrogen bonds directly with the momentarily existing hydrogen bond network of H(2)O, and retard the degree of entropy-volume cross fluctuation inherent in liquid H(2)O. The effect of the latter is stronger for I(-) than Br(-). Here we seek additional information about this qualitative difference between Cl(-) and (Br(-) and I(-)) pair by near infrared (NIR) spectroscopy. We analyze the ν(2) + ν(3) band of H(2)O in the range 4600-5500 cm(-1) of aqueous solutions of NaCl, NaBr and NaI, by a new approach. From observed absorbance, we calculate excess molar absorptivity, ε(E), excess over the additive contributions of solute and solvent. ε(E) thus contains information about the effect of inter-molecular interactions in the ν(2) + ν(3) spectrum. The spectrum of ε(E) shows three bands; two negative ones at 5263 and 4873 cm(-1), and the positive band at 5123 cm(-1). We then define and calculate the excess partial molar absorptivity of each salt, ε(E)(salt). From the behaviour of ε(E)(salt) we suggest that the negative band at 5263 cm(-1) represents free H(2)O without much hydrogen bonding under the influence of local electric field of ions. Furthermore, from a sudden change in the x(salt) (mole fraction of salt) dependence of ε(E)(salt), we suggest that there is an ion-pairing in x(salt) > 0.032, 0.036, and 0.04 for NaCl, NaBr and NaI respectively. The positive band of ε(E) at 5123 cm(-1) is attributed to a modestly organized hydrogen bond network of H(2)O (or liquid-likeness), and the x(salt) dependence of ε indicated a qualitative difference in the effect of Cl(-) from those of Br(-) and I(-). Namely, the values of ε(E)(salt) stay constant for Cl(-) but those for Br(-) and I(-) decrease smoothly on

  15. Interstellar dehydrogenated PAH anions: vibrational spectra

    Science.gov (United States)

    Buragohain, Mridusmita; Pathak, Amit; Sarre, Peter; Gour, Nand Kishor

    2018-03-01

    Interstellar polycyclic aromatic hydrocarbon (PAH) molecules exist in diverse forms depending on the local physical environment. Formation of ionized PAHs (anions and cations) is favourable in the extreme conditions of the interstellar medium (ISM). Besides in their pure form, PAHs are also likely to exist in substituted forms; for example, PAHs with functional groups, dehydrogenated PAHs etc. A dehydrogenated PAH molecule might subsequently form fullerenes in the ISM as a result of ongoing chemical processes. This work presents a density functional theory (DFT) calculation on dehydrogenated PAH anions to explore the infrared emission spectra of these molecules and discuss any possible contribution towards observed IR features in the ISM. The results suggest that dehydrogenated PAH anions might be significantly contributing to the 3.3 μm region. Spectroscopic features unique to dehydrogenated PAH anions are highlighted that may be used for their possible identification in the ISM. A comparison has also been made to see the size effect on spectra of these PAHs.

  16. Laboratory Gas-phase Infrared Spectra of Two Astronomically Relevant PAH Cations: Diindenoperylene, {{\\rm{C}}}_{32}{{\\rm{H}}}_{16}^{+} and Dicoronylene, {{\\rm{C}}}_{48}{{\\rm{H}}}_{20}^{+}

    Science.gov (United States)

    Zhen, Junfeng; Candian, Alessandra; Castellanos, Pablo; Bouwman, Jordy; Linnartz, Harold; Tielens, Alexander G. G. M.

    2018-02-01

    The first gas-phase infrared spectra of two isolated astronomically relevant and large polycyclic aromatic hydrocarbon (PAH) cations—diindenoperylene (DIP) and dicoronylene (DC)—in the 530–1800 cm‑1 (18.9‑5.6 μm) range—are presented. Vibrational band positions are determined for comparison to the aromatic infrared bands. The spectra are obtained via infrared multiphoton dissociation spectroscopy of ions stored in a quadrupole ion trap using the intense and tunable radiation of the free electron laser for infrared experiments (FELIX). DIP+ shows its main absorption peaks at 737 (13.57), 800 (12.50), 1001 (9.99), 1070 (9.35), 1115 (8.97), 1152 (8.68), 1278 (7.83), 1420 (7.04), and 1550 (6.45) cm‑1(μm), in good agreement with density functional theory (DFT) calculations that are uniformly scaled to take anharmonicities into account. DC+ has its main absorption peaks at 853 (11.72), 876 (11.42), 1032 (9.69), 1168 (8.56), 1300 (7.69), 1427 (7.01), and 1566 (6.39) cm‑1(μm), which also agree well with the scaled DFT results presented here. The DIP+ and DC+ spectra are compared with the prominent infrared features observed toward NGC 7023. This results both in matches and clear deviations. Moreover, in the 11.0–14.0 μm region, specific bands can be linked to CH out-of-plane (oop) bending modes of different CH edge structures in large PAHs. The molecular origin of these findings and their astronomical relevance are discussed.

  17. PAH Spectroscopy: Past, Present and Future

    Science.gov (United States)

    Mattioda, Andrew

    2016-01-01

    Since their discovery in the 1970's, astronomers, astrophysicists and astrochemists have been intrigued by the nearly ubiquitous unidentified infrared emission (UIR) bands. In the 1980's, investigators determined the most probably source of these emissions was a family of molecules known as Polycyclic Aromatic Hydrocarbons or simply PAHs. In order to better understand these interstellar IR features and utilize them as chemical probes of the cosmos, laboratory spectroscopists have spent the last three decades investigating the spectroscopy of PAHs under astrophysically relevant conditions. This presentation will discuss the similarities and differences in the spectroscopic properties of PAHs as one goes from the Far to Mid to Near infrared wavelength regions and probe the changes observed in PAH spectra as they go from neutral to ionized molecules suspended in an inert gas matrix, to PAHs in a water ice matrix and as a thin film. In selected instances, the experimental results will be compared to theoretical values. The presentation will conclude with a discussion on the future directions of PAH spectroscopy.

  18. Phenylacetylene and PAH

    Indian Academy of Sciences (India)

    During the last decades, polycyclic aromatic hydrocarbons (PAHs) and other related aromatic compounds, such as ionized PAHs, have received considerable attention from astronomers, astrobiologists, environmentalists, and the combustion community. In the interstellar medium, PAH like species account for up to 10% of ...

  19. LIFTING THE DUSTY VEIL WITH NEAR- AND MID-INFRARED PHOTOMETRY. I. DESCRIPTION AND APPLICATIONS OF THE RAYLEIGH-JEANS COLOR EXCESS METHOD

    International Nuclear Information System (INIS)

    Majewski, Steven R.; Zasowski, Gail; Nidever, David L.

    2011-01-01

    The Milky Way (MW) remains a primary laboratory for understanding the structure and evolution of spiral galaxies, but typically we are denied clear views of MW stellar populations at low Galactic latitudes because of extinction by interstellar dust. However, the combination of Two Micron All-Sky Survey (2MASS) near-infrared (NIR) and Spitzer-IRAC mid-infrared (MIR) photometry enables a powerful method for determining the line-of-sight reddening to any star: the sampled wavelengths lie in the Rayleigh-Jeans part of the spectral energy distribution of most stars, where, to first order, all stars have essentially the same intrinsic color. Thus, changes in stellar NIR-MIR colors due to interstellar reddening are readily apparent, and (under an assumed extinction law) the observed colors and magnitudes of stars can be easily and accurately restored to their intrinsic values, greatly increasing their usefulness for Galactic structure studies. In this paper, we explore this 'Rayleigh-Jeans Color Excess' (RJCE) method and demonstrate that use of even a simple variant of the RJCE method based on a single reference color, (H -[4.5μ]), can rather accurately remove dust effects from previously uninterpretable 2MASS color-magnitude diagrams of stars in fields along the heavily reddened Galactic midplane, with results far superior to those derived from application of other dereddening methods. We also show that 'total' Galactic midplane extinction looks rather different from that predicted using 100μ emission maps from the IRAS/ISSA and COBE/DIRBE instruments as presented by Schlegel et al. Instead, the Galactic midplane extinction strongly resembles the distribution of 13 CO (J = 1→0) emission. Future papers will focus on refining the RJCE method and applying the technique to understand better not only dust and its distribution but also the distribution of stars intermixed with the dust in the low-latitude Galaxy.

  20. Infrared

    Science.gov (United States)

    Vollmer, M.

    2013-11-01

    'Infrared' is a very wide field in physics and the natural sciences which has evolved enormously in recent decades. It all started in 1800 with Friedrich Wilhelm Herschel's discovery of infrared (IR) radiation within the spectrum of the Sun. Thereafter a few important milestones towards widespread use of IR were the quantitative description of the laws of blackbody radiation by Max Planck in 1900; the application of quantum mechanics to understand the rotational-vibrational spectra of molecules starting in the first half of the 20th century; and the revolution in source and detector technologies due to micro-technological breakthroughs towards the end of the 20th century. This has led to much high-quality and sophisticated equipment in terms of detectors, sources and instruments in the IR spectral range, with a multitude of different applications in science and technology. This special issue tries to focus on a few aspects of the astonishing variety of different disciplines, techniques and applications concerning the general topic of infrared radiation. Part of the content is based upon an interdisciplinary international conference on the topic held in 2012 in Bad Honnef, Germany. It is hoped that the information provided here may be useful for teaching the general topic of electromagnetic radiation in the IR spectral range in advanced university courses for postgraduate students. In the most general terms, the infrared spectral range is defined to extend from wavelengths of 780 nm (upper range of the VIS spectral range) up to wavelengths of 1 mm (lower end of the microwave range). Various definitions of near, middle and far infrared or thermal infrared, and lately terahertz frequencies, are used, which all fall in this range. These special definitions often depend on the scientific field of research. Unfortunately, many of these fields seem to have developed independently from neighbouring disciplines, although they deal with very similar topics in respect of the

  1. Near-infrared to Mid-infrared Observations of Galaxy Mergers: NGC 2782 and NGC 7727

    Science.gov (United States)

    Onaka, Takashi; Nakamura, Tomohiko; Sakon, Itsuki; Wu, Ronin; Ohsawa, Ryou; Kaneda, Hidehiro; Lebouteiller, Vianney; Roellig, Thomas L.

    2018-01-01

    We present the results of near-infrared-to-mid-infrared (NIR-to-MIR) imaging and NIR spectroscopic observations of two galaxy mergers, NGC 2782 (Arp 215) and NGC 7727 (Arp 222), with the Infrared Camera on board AKARI. NGC 2782 shows extended MIR emission in the eastern side of the galaxy, which corresponds to the eastern tidal tail seen in the H I 21 cm map, while NGC 7727 shows extended MIR emission in the north of the galaxy, which is similar to the plumes seen in the residual image at the K-band after subtracting a galaxy model. Both extended structures are thought to have formed in association with their merger events. They show excess emission at 7–15 μm, which can be attributed to emission from polycyclic aromatic hydrocarbons (PAHs), while the observed spectral energy distributions (SEDs) decline longward of 24 μm, suggesting that very small grains (VSGs) are deficient. These characteristics of the observed MIR SED may be explained if PAHs are formed by fragmentation of VSGs during merger events. The star formation rate is estimated from the MIR PAH emission in the eastern tail region of NGC 2782 and it is in fair agreement with those estimated from Hα and [C II] 158 μm. MIR observations are efficient for the study of dust processing and structures formed during merger events.

  2. WIRED for EC: New White Dwarfs with WISE Infrared Excesses and New Classification Schemes from the Edinburgh–Cape Blue Object Survey

    Energy Technology Data Exchange (ETDEWEB)

    Dennihy, E.; Clemens, J. C.; Dunlap, B. H.; O’Brien, P. C.; Fuchs, J. T. [Physics and Astronomy Department, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 (United States); Debes, John H. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Kilkenny, D. [Department of Physics, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa)

    2017-11-10

    We present a simple method for identifying candidate white dwarf systems with dusty exoplanetary debris based on a single temperature blackbody model fit to the infrared excess. We apply this technique to a sample of Southern Hemisphere white dwarfs from the recently completed Edinburgh–Cape Blue Object Survey and identify four new promising dusty debris disk candidates. We demonstrate the efficacy of our selection method by recovering three of the four Spitzer confirmed dusty debris disk systems in our sample. Further investigation using archival high-resolution imaging shows that Spitzer data of the unrecovered fourth object is likely contaminated by a line-of-sight object that either led to a misclassification as a dusty disk in the literature or is confounding our method. Finally, in our diagnostic plot, we show that dusty white dwarfs, which also host gaseous debris, lie along a boundary of our dusty debris disk region, providing clues to the origin and evolution of these especially interesting systems.

  3. The PAH Emission Characteristics of the Reflection Nebula NGC 2023

    International Nuclear Information System (INIS)

    Peeters, Els; Bauschlicher, Charles W. Jr.; Allamandola, Louis J.; Tielens, Alexander G. G. M.; Ricca, Alessandra; Wolfire, Mark G.

    2017-01-01

    We present 5–20 μ m spectral maps of the reflection nebula NGC 2023 obtained with the Infrared Spectrograph SL and SH modes on board the Spitzer Space Telescope, which reveal emission from polycyclic aromatic hydrocarbons (PAHs), C 60 , and H 2 superposed on a dust continuum. We show that several PAH emission bands correlate with each other and exhibit distinct spatial distributions that reveal a spatial sequence with distance from the illuminating star. We explore the distinct morphology of the 6.2, 7.7, and 8.6 μ m PAH bands and find that at least two spatially distinct components contribute to the 7–9 μ m PAH emission in NGC 2023. We report that the PAH features behave independently of the underlying plateaus. We present spectra of compact, oval PAHs ranging in size from C 66 to C 210 , determined computationally using density functional theory, and we investigate trends in the band positions and relative intensities as a function of PAH size, charge, and geometry. Based on the NASA Ames PAH database, we discuss the 7–9 μ m components in terms of band assignments and relative intensities. We assign the plateau emission to very small grains with possible contributions from PAH clusters and identify components in the 7–9 μ m emission that likely originate in these structures. Based on the assignments and the observed spatial sequence, we discuss the photochemical evolution of the interstellar PAH family as the PAHs are more and more exposed to the radiation field of the central star in the evaporative flows associated with the Photo-Dissociation Regions in NGC 2023.

  4. The PAH Emission Characteristics of the Reflection Nebula NGC 2023

    Energy Technology Data Exchange (ETDEWEB)

    Peeters, Els [Department of Physics and Astronomy, University of Western Ontario, London, ON N6A 3K7 (Canada); Bauschlicher, Charles W. Jr. [Entry Systems and Technology Division, Mail Stop 230-3, NASA Ames Research Center, Moffett Field, CA 94035 (United States); Allamandola, Louis J. [NASA Ames Research Center, Space Science Division, Mail Stop 245-6, Moffett Field, CA 94035 (United States); Tielens, Alexander G. G. M. [Leiden Observatory, P.O. Box 9513, 2300 RA Leiden (Netherlands); Ricca, Alessandra [Carl Sagan Center, SETI Institute, 189 N. Bernardo Avenue, Suite 100, Mountain View, CA 94043 (United States); Wolfire, Mark G., E-mail: epeeters@uwo.ca [Astronomy Department, University of Maryland, College Park, MD 20742 (United States)

    2017-02-20

    We present 5–20 μ m spectral maps of the reflection nebula NGC 2023 obtained with the Infrared Spectrograph SL and SH modes on board the Spitzer Space Telescope, which reveal emission from polycyclic aromatic hydrocarbons (PAHs), C{sub 60}, and H{sub 2} superposed on a dust continuum. We show that several PAH emission bands correlate with each other and exhibit distinct spatial distributions that reveal a spatial sequence with distance from the illuminating star. We explore the distinct morphology of the 6.2, 7.7, and 8.6 μ m PAH bands and find that at least two spatially distinct components contribute to the 7–9 μ m PAH emission in NGC 2023. We report that the PAH features behave independently of the underlying plateaus. We present spectra of compact, oval PAHs ranging in size from C{sub 66} to C{sub 210}, determined computationally using density functional theory, and we investigate trends in the band positions and relative intensities as a function of PAH size, charge, and geometry. Based on the NASA Ames PAH database, we discuss the 7–9 μ m components in terms of band assignments and relative intensities. We assign the plateau emission to very small grains with possible contributions from PAH clusters and identify components in the 7–9 μ m emission that likely originate in these structures. Based on the assignments and the observed spatial sequence, we discuss the photochemical evolution of the interstellar PAH family as the PAHs are more and more exposed to the radiation field of the central star in the evaporative flows associated with the Photo-Dissociation Regions in NGC 2023.

  5. Hydrogenated Benzene in Circumstellar Environments: Insights into the Photostability of Super-hydrogenated PAHs

    Science.gov (United States)

    Quitián-Lara, Heidy M.; Fantuzzi, Felipe; Nascimento, Marco A. C.; Wolff, Wania; Boechat-Roberty, Heloisa M.

    2018-02-01

    Polycyclic aromatic hydrocarbons (PAHs), comprised of fused benzene (C6H6) rings, emit infrared radiation (3–12 μm) due to the vibrational transitions of the C–H bonds of the aromatic rings. The 3.3 μm aromatic band is generally accompanied by the band at 3.4 μm assigned to the vibration of aliphatic C–H bonds of compounds such as PAHs with an excess of peripheral H atoms (H n –PAHs). Herein we study the stability of fully hydrogenated benzene (or cyclohexane, C6H12) under the impact of stellar radiation in the photodissociation region (PDR) of NGC 7027. Using synchrotron radiation and time-of-flight mass spectrometry, we investigated the ionization and dissociation processes at energy ranges of UV (10–200 eV) and soft X-rays (280–310 eV). Density Functional Theory (DFT) calculations were used to determine the most stable structures and the relevant low-lying isomers of singly charged C6H12 ions. Partial Ion Yield (PIY) analysis gives evidence of the higher tendency toward dissociation of cyclohexane in comparison to benzene. However, because of the high photoabsorption cross-section of benzene at the C1s resonance edge, its photodissociation and photoionization cross-sections are enhanced, leading to a higher efficiency of dissociation of benzene in the PDR of NGC 7027. We suggest that a similar effect is experienced by PAHs in X-ray photon-rich environments, which ultimately acts as an auxiliary protection mechanism of super-hydrogenated polycyclic hydrocarbons. Finally, we propose that the single photoionization of cyclohexane could enhance the abundance of branched molecules in interstellar and circumstellar media.

  6. PAH processing in space

    NARCIS (Netherlands)

    Micelotta, Elisabetta Rita

    2009-01-01

    Polycyclic Aromatic Hydrocarbons (PAHs) are one of the most common chemical compounds on Earth. These big molecules are naturally present in crude oil and coal deposits, and are also formed by incomplete combustion of carbon-containing fuels, hence they are found in car exhaust, cigarette smoke and

  7. PHOTOCHEMISTRY OF POLYCYCLIC AROMATIC HYDROCARBONS IN COSMIC WATER ICE: THE ROLE OF PAH IONIZATION AND CONCENTRATION

    International Nuclear Information System (INIS)

    Cook, Amanda M.; Mattioda, Andrew L.; Roser, Joseph; Bregman, Jonathan; Ricca, Alessandra; Allamandola, Louis J.; Bouwman, Jordy; Linnartz, Harold

    2015-01-01

    Infrared spectroscopic studies of ultraviolet (UV) irradiated, water-rich, cosmic ice analogs containing small polycyclic aromatic hydrocarbons (PAHs) are described. The irradiation studies of anthracene:H 2 O, pyrene:H 2 O, and benzo[ghi]perylene:H 2 O ices (14 K) at various concentrations reported by Bouwman et al. are extended. While aromatic alcohols and ketones have been reported in residues after irradiated PAH:H 2 O ices were warmed to 270 K, it was not known if they formed during ice irradiation or during warm-up when reactants interact as H 2 O sublimes. Recent work has shown that they form in low temperature ice. Using DFT computed IR spectra to identify photoproducts and PAH cations, we tentatively identify the production of specific alcohols [PAH(OH) n ] and quinones [PAH(O) n ] for all PAH:H 2 O ices considered here. Little evidence is found for hydrogenation at 14 K, consistent with the findings of Gudipati and Yang. Addition of O and OH to the parent PAH is the dominant photochemical reaction, but PAH erosion to smaller PAHs (producing CO 2 and H 2 CO) is also important. DFT spectra are used to assess the contribution of PAH-related species to interstellar absorption features from 5 to 9 μm. The case is made that PAH cations are important contributors to the C2 component and PAH(OH) n and PAH(O) n to the C5 component described by Boogert et al. Thus, interstellar ices should contain neutral and ionized PAHs, alcohols, ketones and quinones at the ∼2%-4% level relative to H 2 O. PAHs, their photoproducts, and ion-mediated processes should therefore be considered when modeling interstellar ice processes

  8. PHOTOCHEMISTRY OF POLYCYCLIC AROMATIC HYDROCARBONS IN COSMIC WATER ICE: THE ROLE OF PAH IONIZATION AND CONCENTRATION

    Energy Technology Data Exchange (ETDEWEB)

    Cook, Amanda M.; Mattioda, Andrew L.; Roser, Joseph; Bregman, Jonathan [NASA Ames Research Center, PO Box 1, M/S 245-6, Moffett Field, CA 94035 (United States); Ricca, Alessandra; Allamandola, Louis J. [SETI Institute, 189 North Bernardo Avenue, Mountain View, CA 94043 (United States); Bouwman, Jordy [Radboud University Nijmegen, Institute for Molecules and Materials, Toernooiveld 5, 6525 ED Nijmegen (Netherlands); Linnartz, Harold [Sackler Laboratory for Astrophysics, Leiden Observatory, University of Leiden, PO Box 9513, NL2300 RA Leiden (Netherlands)

    2015-01-20

    Infrared spectroscopic studies of ultraviolet (UV) irradiated, water-rich, cosmic ice analogs containing small polycyclic aromatic hydrocarbons (PAHs) are described. The irradiation studies of anthracene:H{sub 2}O, pyrene:H{sub 2}O, and benzo[ghi]perylene:H{sub 2}O ices (14 K) at various concentrations reported by Bouwman et al. are extended. While aromatic alcohols and ketones have been reported in residues after irradiated PAH:H{sub 2}O ices were warmed to 270 K, it was not known if they formed during ice irradiation or during warm-up when reactants interact as H{sub 2}O sublimes. Recent work has shown that they form in low temperature ice. Using DFT computed IR spectra to identify photoproducts and PAH cations, we tentatively identify the production of specific alcohols [PAH(OH) {sub n} ] and quinones [PAH(O) {sub n} ] for all PAH:H{sub 2}O ices considered here. Little evidence is found for hydrogenation at 14 K, consistent with the findings of Gudipati and Yang. Addition of O and OH to the parent PAH is the dominant photochemical reaction, but PAH erosion to smaller PAHs (producing CO{sub 2} and H{sub 2}CO) is also important. DFT spectra are used to assess the contribution of PAH-related species to interstellar absorption features from 5 to 9 μm. The case is made that PAH cations are important contributors to the C2 component and PAH(OH) {sub n} and PAH(O) {sub n} to the C5 component described by Boogert et al. Thus, interstellar ices should contain neutral and ionized PAHs, alcohols, ketones and quinones at the ∼2%-4% level relative to H{sub 2}O. PAHs, their photoproducts, and ion-mediated processes should therefore be considered when modeling interstellar ice processes.

  9. A Resolved and Asymmetric Ring of PAHs within the Young Circumstellar Disk of IRS 48

    Energy Technology Data Exchange (ETDEWEB)

    Schworer, Guillaume; Lacour, Sylvestre; Du Foresto, Vincent Coudé [LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universits, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cité (France); Huélamo, Nuria [Dpto. Astrofísica, Centro de Astrobiología (INTA-CSIC), ESAC Campus, P.O. Box 78, E-28691, Villanueva de la Cañada (Spain); Pinte, Christophe; Chauvin, Gaël [Univ. Grenoble Alpes, IPAG, F-38000 Grenoble, France CNRS, IPAG, F-38000 Grenoble (France); Ehrenreich, David [Observatoire de l’Université de Genève, 51 chemin des Maillettes, 1290 Versoix (Switzerland); Girard, Julien [European Southern Observatory, Alonso de Cordova 3107, Casilla 19001 Vitacura, Santiago 19 (Chile); Tuthill, Peter [Sydney Institute for Astronomy, School of Physics, The University of Sydney, NSW 2006 (Australia)

    2017-06-20

    For one decade, the spectral type and age of the ρ Oph object IRS-48 were subject to debate and mystery. Modeling its disk with mid-infrared to millimeter observations led to various explanations to account for the complex intricacy of dust holes and gas-depleted regions. We present multi-epoch high-angular-resolution interferometric near-infrared data of spatially resolved emissions in the first 15 au of IRS-48, known to have very strong polycyclic aromatic hydrocarbon (PAH) emissions within this dust-depleted region. We make use of new Sparse-Aperture-Masking data to instruct a revised radiative-transfer model, where spectral energy distribution fluxes and interferometry are jointly fitted. Neutral and ionized PAH, very small grains (VSG), and classical silicates are incorporated into the model; new stellar parameters and extinction laws are explored. A bright (42 L {sub ⊙}) and hence large (2.5 R {sub ⊙}) central star with A {sub v} = 12.5 mag and R {sub v} = 6.5 requires less near-infrared excess: the inner-most disk at ≈1 au is incompatible with the interferometric data. The revised stellar parameters place this system on a 4 Myr evolutionary track, four times younger than the previous estimations, which is in better agreement with the surrounding ρ Oph region and disk-lifetime observations. The disk-structure solution converges to a classical-grain outer disk from 55 au combined with an unsettled and fully resolved VSG and PAH ring, between 11 and 26 au. We find two overluminosities in the PAH ring at color-temperatures consistent with the radiative transfer simulations; one follows a Keplerian circular orbit at 14 au. We show a depletion of a factor of ≈5 of classical dust grains up to 0.3 mm compared to very small particles: the IRS-48 disk is nearly void of dust grains in the first 55 au. A 3.5 M {sub Jup} planet on a 40 au orbit can qualitatively explain the new disk structure.

  10. Ca2+ promoted the low transformation efficiency of plasmid DNA exposed to PAH contaminants.

    Directory of Open Access Journals (Sweden)

    Fuxing Kang

    Full Text Available The effects of interactions between genetic materials and polycyclic aromatic hydrocarbons (PAHs on gene expression in the extracellular environment remain to be elucidated and little information is currently available on the effect of ionic strength on the transformation of plasmid DNA exposed to PAHs. Phenanthrene and pyrene were used as representative PAHs to evaluate the transformation of plasmid DNA after PAH exposure and to determine the role of Ca(2+ during the transformation. Plasmid DNA exposed to the test PAHs demonstrated low transformation efficiency. In the absence of PAHs, the transformation efficiency was 4.7 log units; however, the efficiency decreased to 3.72-3.14 log units with phenanthrene/pyrene exposures of 50 µg · L(-1. The addition of Ca(2+ enhanced the low transformation efficiency of DNA exposed to PAHs. Based on the co-sorption of Ca(2+ and phenanthrene/pyrene by DNA, we employed Fourier-transform infrared spectroscopy (FTIR, X-ray photoelectron spectroscopy (XPS, and mass spectrometry (MS to determine the mechanisms involved in PAH-induced DNA transformation. The observed low transformation efficiency of DNA exposed to either phenanthrene or pyrene can be attributed to a broken hydrogen bond in the double helix caused by planar PAHs. Added Ca(2+ formed strong electrovalent bonds with "-POO(--" groups in the DNA, weakening the interaction between PAHs and DNA based on weak molecular forces. This decreased the damage of PAHs to hydrogen bonds in double-stranded DNA by isolating DNA molecules from PAHs and consequently enhanced the transformation efficiency of DNA exposed to PAH contaminants. The findings provide insight into the effects of anthropogenic trace PAHs on DNA transfer in natural environments.

  11. Photochemistry of PAHs in cosmic water ice. The effect of concentration on UV-VIS spectroscopy and ionization efficiency

    Science.gov (United States)

    Cuylle, Steven H.; Allamandola, Louis J.; Linnartz, Harold

    2014-02-01

    Context. Observations and models show that polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the interstellar medium. Like other molecules in dense clouds, PAHs accrete onto interstellar dust grains, where they are embedded in an ice matrix dominated by water. In the laboratory, mixed molecular ices (not containing PAHs) have been extensively studied using Fourier transform infrared absorption spectroscopy. Experiments including PAHs in ices have started, however, the concentrations used are typically much higher than the concentrations expected for interstellar ices. Optical spectroscopy offers a sensitive alternative. Aims: We report an experimental study of the effect PAH concentration has on the electronic spectra and the vacuum UV (VUV) driven processes of PAHs in water-rich ices. The goal is to apply the outcome to cosmic ices. Methods: Optical spectroscopic studies allow us to obtain in-situ and quasi real-time electronic solid state spectra of two prototypical PAHs (pyrene and coronene) embedded in water ice under VUV photoprocessing. The study is carried out on PAH:H2O concentrations in the range of 1:30 000 to pure PAH, covering the temperature range from 12 to 125 K. Results: PAH concentration strongly influences the efficiency of PAH cation formation. At low concentrations, ionization efficiencies are over 60% dropping to about 15% at 1:1000. Increasing the PAH concentration reveals spectral broadening in neutral and cation PAH spectra attributed to PAH clustering inside the ice. At the PAH concentrations expected for interstellar ices, some 10 to 20% may be present as cations. The presence of PAHs in neutral and ion form will add distinctive absorption bands to cosmic ice optical spectra and this may serve as a tool to determine PAH concentrations.

  12. Biodegradation of Mixed PAHs by PAH-Degrading Endophytic Bacteria

    Directory of Open Access Journals (Sweden)

    Xuezhu Zhu

    2016-08-01

    Full Text Available Endophytic bacteria can promote plant growth, induce plant defence mechanisms, and increase plant resistance to organic contaminants. The aims of the present study were to isolate highly PAH-degrading endophytic bacteria from plants growing at PAH-contaminated sites and to evaluate the capabilities of these bacteria to degrade polycyclic aromatic hydrocarbons (PAHs in vitro, which will be beneficial for re-colonizing target plants and reducing plant PAH residues through the inoculation of plants with endophytic bacteria. Two endophytic bacterial strains P1 (Stenotrophomonas sp. and P3 (Pseudomonas sp., which degraded more than 90% of phenanthrene (PHE within 7 days, were isolated from Conyza canadensis and Trifolium pretense L., respectively. Both strains could use naphthalene (NAP, PHE, fluorene (FLR, pyrene (PYR, and benzo(apyrene (B(aP as the sole sources of carbon and energy. Moreover, these bacteria reduced the contamination of mixed PAHs at high levels after inoculation for 7 days; strain P1 degraded 98.0% NAP, 83.1% FLR, 87.8% PHE, 14.4% PYR, and 1.6% B(aP, and strain P3 degraded 95.3% NAP, 87.9% FLR, 90.4% PHE, 6.9% PYR, and negligible B(aP. Notably, the biodegradation of PAHs could be promoted through additional carbon and nitrogen nutrients; therein, beef extract was suggested as the optimal co-substrate for the degradation of PAHs by these two strains (99.1% PHE was degraded within 7 days. Compared with strain P1, strain P3 has more potential for the use in the removal of PAHs from plant tissues. These results provide a novel perspective in the reduction of plant PAH residues in PAH-contaminated sites through inoculating plants with highly PAH-degrading endophytic bacteria.

  13. THE ORIGIN OF THE 24 μm EXCESS IN RED GALAXIES

    International Nuclear Information System (INIS)

    Brand, Kate; Moustakas, John; Armus, Lee; Desai, Vandana; Assef, Roberto J.; Kochanek, Christopher S.; Soifer, B. T.; Brown, Michael J. I.; Cool, Richard R.; Dey, Arjun; Jannuzi, Buell T.; Le Floc'h, Emeric; Melbourne, Jason; Papovich, Casey J.

    2009-01-01

    Observations with the Spitzer Space Telescope have revealed a population of red sequence galaxies with a significant excess in their 24 μm emission compared to what is expected from an old stellar population. We identify ∼900 red galaxies with 0.15 ≤ z ≤ 0.3 from the AGN and Galaxy Evolution Survey (AGES) selected from the NOAO Deep Wide-Field Survey Booetes field. Using Spitzer MIPS, we classify 89 (∼10%) with 24 μm infrared excess (f 24 ≥ 0.3 mJy). We determine the prevalence of active galactic nucleus (AGN) and star-formation activity in all the AGES galaxies using optical line diagnostics and mid-IR color-color criteria. Using the IRAC color-color diagram from the Spitzer Shallow Survey, we find that 64% of the 24 μm excess red galaxies are likely to have strong polycyclic aromatic hydrocarbon (PAH) emission features in the 8 μm IRAC band. This fraction is significantly larger than the 5% of red galaxies with f 24 < 0.3 mJy that are estimated to have strong PAH emission, suggesting that the infrared emission is largely due to star-formation processes. Only 15% of the 24 μm excess red galaxies have optical line diagnostics characteristic of star formation (64% are classified as AGN and 21% are unclassifiable). The difference between the optical and infrared results suggests that both AGN and star-formation activity are occurring simultaneously in many of the 24 μm excess red galaxies. These results should serve as a warning to studies that exclusively use optical line diagnostics to determine the dominant emission mechanism in the infrared and other bands. We find that ∼40% of the 24 μm excess red galaxies are edge-on spiral galaxies with high optical extinctions. The remaining sources are likely to be red galaxies whose 24 μm emission comes from a combination of obscured AGN and star-formation activity.

  14. DETECTIONS OF WATER ICE, HYDROCARBONS, AND 3.3 μm PAH IN z ∼ 2 ULIRGs

    International Nuclear Information System (INIS)

    Sajina, Anna; Spoon, Henrik; Yan Lin; Imanishi, Masatoshi; Fadda, Dario; Elitzur, Moshe

    2009-01-01

    We present the first detections of the 3 μm water ice and 3.4 μm amorphous hydrocarbon (HAC) absorption features in z ∼ 2 ULIRGs. These are based on deep rest-frame 2-8 μm Spitzer Infrared Spectrograph spectra of 11 sources selected for their appreciable silicate absorption. The HAC-to-silicate ratio for our z ∼ 2 sources is typically higher by a factor of 2-5 than that observed in the Milky Way. This HAC 'excess' suggests compact nuclei with steep temperature gradients as opposed to predominantly host obscuration. Beside the above molecular absorption features, we detect the 3.3 μm polycyclic aromatic hydrocarbon (PAH) emission feature in one of our sources with three more individual spectra showing evidence for it. Stacking analysis suggests that water ice, hydrocarbons, and PAH are likely present in the bulk of this sample even when not individually detected. The most unexpected result of our study is the lack of clear detections of the 4.67 μm CO gas absorption feature. Only three of the sources show tentative signs of this feature at significantly lower levels than has been observed in local ULIRGs. Overall we find that the closest local analogs to our sources, in terms of 3-4 μm color, HAC-to-silicate and ice-to-silicate ratios, as well as low PAH equivalent widths, are sources dominated by deeply obscured nuclei. Such sources form only a small fraction of ULIRGs locally and are commonly believed to be dominated by buried active galactic nuclei (AGNs). Our sample suggests that, in an absolute number, such buried AGNs are at least an order of magnitude more common at z ∼ 2 than today. The presence of PAH suggests that significant levels of star formation are present even if the obscured AGNs typically dominate the power budget.

  15. RADIO AND MID-INFRARED PROPERTIES OF COMPACT STARBURSTS: DISTANCING THEMSELVES FROM THE MAIN SEQUENCE

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, E. J. [Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Stierwalt, S.; Armus, L. [Spitzer Science Center, California Institute of Technology, MC 314-6, Pasadena, CA 91125 (United States); Condon, J. J. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Evans, A. S., E-mail: emurphy@obs.carnegiescience.edu [Department of Astronomy, University of Virginia, 530 McCormick Road, Charlottesville, VA 22904 (United States)

    2013-05-01

    We investigate the relationship between 8.44 GHz brightness temperatures and 1.4 to 8.44 GHz radio spectral indices with 6.2 {mu}m polycyclic aromatic hydrocarbon (PAH) emission and 9.7 {mu}m silicate absorption features for a sample of 36 local luminous and ultraluminous infrared galaxies. We find that galaxies having small 6.2 {mu}m PAH equivalent widths (EQWs), which signal the presence of weak PAH emission and/or an excess of very hot dust, also have flat spectral indices. The three active galactic nuclei (AGN) identified through their excessively large 8.44 GHz brightness temperatures are also identified as AGN via their small 6.2 {mu}m PAH EQWs. We also find that the flattening of the radio spectrum increases with increasing silicate optical depth, 8.44 GHz brightness temperature, and decreasing size of the radio source even after removing potential AGN, supporting the idea that compact starbursts show spectral flattening as the result of increased free-free absorption. These correlations additionally suggest that the dust obscuration in these galaxies must largely be coming from the vicinity of the compact starburst itself, and is not distributed throughout the (foreground) disk of the galaxy. Finally, we investigate the location of these infrared-bright systems relative to the main sequence (star formation rate versus stellar mass) of star-forming galaxies in the local universe. We find that the radio spectral indices of galaxies flatten with increasing distance above the main sequence, or in other words, with increasing specific star formation rate. This indicates that galaxies located above the main sequence, having high specific star formation rates, are typically compact starbursts hosting deeply embedded star formation that becomes more optically thick in the radio and infrared with increased distance above the main sequence.

  16. The infrared flux method and its use for study of α Boo, μ Her and β Dra; relation to the Vega 1.2-5 μm infrared excess

    International Nuclear Information System (INIS)

    Blackwell, D.E.; Booth, A.J.; Petford, A.D.; Leggett, S.K.; Mountain, C.M.; Selby, M.J.

    1986-01-01

    The effective temperatures of α Boo, μ Her, and β Dra are determined using the infrared flux method. The determinations are based on the high-quality spectrophotometric data obtained from an aircraft by previous authors, the new infrared calibration of Vega obtained from observations made at Tenerife between 1979 and 1983, the use of a Reticon spectrometer to determine the integrated fluxes in the region 370-950 nm, and the use of model atmospheres constructed with the previously developed MARCS code. (author)

  17. Accumulation, allocation, and risk assessment of polycyclic aromatic hydrocarbons (PAHs in soil-Brassica chinensis system.

    Directory of Open Access Journals (Sweden)

    Juan Zhang

    Full Text Available Farmland soil and leafy vegetables accumulate more polycyclic aromatic hydrocarbons (PAHs in suburban sites. In this study, 13 sampling areas were selected from vegetable fields in the outskirts of Xi'an, the largest city in northwestern China. The similarity of PAH composition in soil and vegetation was investigated through principal components analysis and redundancy analysis (RDA, rather than discrimination of PAH congeners from various sources. The toxic equivalent quantity of PAHs in soil ranged from 7 to 202 μg/kg d.w., with an average of 41 μg/kg d.w., which exceeded the agricultural/horticultural soil acceptance criteria for New Zealand. However, the cancer risk level posed by combined direct ingestion, dermal contact, inhalation of soil particles, and inhalation of surface soil vapor met the rigorous international criteria (1 × 10(-6. The concentration of total PAHs was (1052 ± 73 μg/kg d.w. in vegetation (mean ± standard error. The cancer risks posed by ingestion of vegetation ranged from 2×10-5 to 2 × 10(-4 with an average of 1.66 × 10(-4, which was higher than international excess lifetime risk limits for carcinogens (1 × 10(-4. The geochemical indices indicated that the PAHs in soil and vegetables were mainly from vehicle and crude oil combustion. Both the total PAHs in vegetation and bioconcentration factor for total PAHs (the ratio of total PAHs in vegetation to total PAHs in soil increased with increasing pH as well as decreasing sand in soil. The total variation in distribution of PAHs in vegetation explained by those in soil reached 98% in RDA, which was statistically significant based on Monte Carlo permutation. Common pollution source and notable effects of soil contamination on vegetation would result in highly similar distribution of PAHs in soil and vegetation.

  18. Excessive growth.

    Science.gov (United States)

    Narayanaswamy, Vasudha; Rettig, Kenneth R; Bhowmick, Samar K

    2008-09-01

    Tall stature and excessive growth syndrome are a relatively rare concern in pediatric practice. Nevertheless, it is important to identify abnormal accelerated growth patterns in children, which may be the clue in the diagnosis of an underlying disorder. We present a case of pituitary gigantism in a 2 1/2-year-old child and discuss the signs, symptoms, laboratory findings, and the treatment. Brief discussions on the differential diagnosis of excessive growth/tall stature have been outlined. Pituitary gigantism is very rare in the pediatrics age group; however, it is extremely rare in a child that is less than 3 years of age. The nature of pituitary adenoma and treatment options in children with this condition have also been discussed.

  19. PAHs in Translucent Interstellar Clouds

    Science.gov (United States)

    Salama, Farid; Galazutdinov, G.; Krelowski, J.; Biennier, L.; Beletsky, Y.; Song, I.

    2011-05-01

    We discuss the proposal of relating the origin of some of the diffuse interstellar bands (DIBs) to neutral polycyclic aromatic hydrocarbons (PAHs) present in translucent interstellar clouds. The spectra of several cold, isolated gas-phase PAHs have been measured in the laboratory under experimental conditions that mimic the interstellar conditions and are compared with an extensive set of astronomical spectra of reddened, early type stars. This comparison provides - for the first time - accurate upper limits for the abundances of specific PAH molecules along specific lines-of-sight. Something that is not attainable from IR observations alone. The comparison of these unique laboratory data with high resolution, high S/N ratio astronomical observations leads to two major findings: (1) a finding specific to the individual molecules that were probed in this study and, which leads to the clear and unambiguous conclusion that the abundance of these specific neutral PAHs must be very low in the individual translucent interstellar clouds that were probed in this survey (PAH features remain below the level of detection) and, (2) a general finding that neutral PAHs exhibit intrinsic band profiles that are similar to the profile of the narrow DIBs indicating that the carriers of the narrow DIBs must have close molecular structure and characteristics. This study is the first quantitative survey of neutral PAHs in the optical range and it opens the way for unambiguous quantitative searches of PAHs in a variety of interstellar and circumstellar environments. // Reference: F. Salama et al. (2011) ApJ. 728 (1), 154 // Acknowledgements: F.S. acknowledges the support of the NASA's Space Mission Directorate APRA Program. J.K. acknowledges the financial support of the Polish State (grant N203 012 32/1550). The authors are deeply grateful to the ESO archive as well as to the ESO staff members for their active support.

  20. SPATIAL VARIATIONS OF PAH PROPERTIES IN M17SW REVEALED BY SPITZER /IRS SPECTRAL MAPPING

    Energy Technology Data Exchange (ETDEWEB)

    Yamagishi, M. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Chuo-ku, Sagamihara 252-5210 (Japan); Kaneda, H.; Ishihara, D.; Oyabu, S.; Suzuki, T.; Nishimura, A.; Kohno, M. [Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602 (Japan); Onaka, T.; Ohashi, S. [Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Nagayama, T.; Matsuo, M. [Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima 890-0065 (Japan); Umemoto, T.; Minamidani, T.; Fujita, S. [Nobeyama Radio Observatory, National Astronomical Observatory of Japan (NAOJ), National Institutes of Natural Sciences (NINS), 462-2, Nobeyama, Minamimaki, Minamisaku, Nagano 384-1305 (Japan); Tsuda, Y., E-mail: yamagish@ir.isas.jaxa.jp [Graduate School of Science and Engineering, Meisei University, 2-1-1 Hodokubo, Hino, Tokyo 191-0042 (Japan)

    2016-12-20

    We present Spitzer /IRS mid-infrared spectral maps of the Galactic star-forming region M17 as well as IRSF/SIRIUS Br γ and Nobeyama 45 m/FOREST {sup 13}CO ( J = 1–0) maps. The spectra show prominent features due to polycyclic aromatic hydrocarbons (PAHs) at wavelengths of 6.2, 7.7, 8.6, 11.3, 12.0, 12.7, 13.5, and 14.2  μ m. We find that the PAH emission features are bright in the region between the H ii region traced by Br γ and the molecular cloud traced by {sup 13}CO, supporting that the PAH emission originates mostly from photo-dissociation regions. Based on the spatially resolved Spitzer /IRS maps, we examine spatial variations of the PAH properties in detail. As a result, we find that the interband ratio of PAH 7.7  μ m/PAH 11.3  μ m varies locally near M17SW, but rather independently of the distance from the OB stars in M17, suggesting that the degree of PAH ionization is mainly controlled by local conditions rather than the global UV environments determined by the OB stars in M17. We also find that the interband ratios of the PAH 12.0  μ m, 12.7  μ m, 13.5  μ m, and 14.2  μ m features to the PAH 11.3  μ m feature are high near the M17 center, which suggests structural changes of PAHs through processing due to intense UV radiation, producing abundant edgy irregular PAHs near the M17 center.

  1. PAH in tea and coffee

    DEFF Research Database (Denmark)

    Duedahl-Olesen, Lene; Navarantem, Marin; Adamska, Joanna

    For food regulation in the European Union maximum limits on other foods than tea and coffee includes benzo[a]pyrene and the sum of PAH4 (sum of benzo[a]pyrene, chrysene, benz[a]anthracene and benzo[b]fluoranthene). This study includes analysis of the above mentioned PAH in both, tea leaves, coffee...... beans and ready-to-drink preparations. Compared to other food matrices (e.g. fish), the analytical methods were challenged by the hot water extracts. Preparation of tea includes roasting and drying of the tea leaves using combustion gases from burning wood, oil, or coal. These are responsible...... for accumulation of PAH in tea leaves. Different varieties of tea leaves were analyzed and highest concentrations were found in leaves from mate and black tea with maximum concentrations of 32 μg/kg for benzo[a]pyrene and 115 μg/kg for the sum of PAH4. Also, coffee beans are roasted during processing. However...

  2. Removal Capacities of Polycyclic Aromatic Hydrocarbons (PAHs by a Newly Isolated Strain from Oilfield Produced Water

    Directory of Open Access Journals (Sweden)

    Yi-Bin Qi

    2017-02-01

    Full Text Available The polycyclic aromatic hydrocarbon (PAH-degrading strain Q8 was isolated from oilfield produced water. According to the analysis of a biochemical test, 16S rRNA gene, house-keeping genes and DNA–DNA hybridization, strain Q8 was assigned to a novel species of the genus Gordonia. The strain could not only grow in mineral salt medium (MM and utilize naphthalene and pyrene as its sole carbon source, but also degraded mixed naphthalene, phenanthrene, anthracene and pyrene. The degradation ratio of these four PAHs reached 100%, 95.4%, 73.8% and 53.4% respectively after being degraded by Q8 for seven days. A comparative experiment found that the PAHs degradation efficiency of Q8 is higher than that of Gordonia alkaliphila and Gordonia paraffinivorans, which have the capacities to remove PAHs. Fourier transform infrared spectra, saturate, aromatic, resin and asphaltene (SARA and gas chromatography–mass spectrometry (GC–MS analysis of crude oil degraded by Q8 were also studied. The results showed that Q8 could utilize n-alkanes and PAHs in crude oil. The relative proportions of the naphthalene series, phenanthrene series, thiophene series, fluorene series, chrysene series, C21-triaromatic steroid, pyrene, and benz(apyrene were reduced after being degraded by Q8. Gordonia sp. nov. Q8 had the capacity to remediate water and soil environments contaminated by PAHs or crude oil, and provided a feasible way for the bioremediation of PAHs and oil pollution.

  3. Impact of natural gas extraction on PAH levels in ambient air.

    Science.gov (United States)

    Paulik, L Blair; Donald, Carey E; Smith, Brian W; Tidwell, Lane G; Hobbie, Kevin A; Kincl, Laurel; Haynes, Erin N; Anderson, Kim A

    2015-04-21

    Natural gas extraction, often referred to as "fracking," has increased rapidly in the U.S. in recent years. To address potential health impacts, passive air samplers were deployed in a rural community heavily affected by the natural gas boom. Samplers were analyzed for 62 polycyclic aromatic hydrocarbons (PAHs). Results were grouped based on distance from each sampler to the nearest active well. PAH levels were highest when samplers were closest to active wells. Additionally, PAH levels closest to natural gas activity were an order of magnitude higher than levels previously reported in rural areas. Sourcing ratios indicate that PAHs were predominantly petrogenic, suggesting that elevated PAH levels were influenced by direct releases from the earth. Quantitative human health risk assessment estimated the excess lifetime cancer risks associated with exposure to the measured PAHs. Closest to active wells, the risk estimated for maximum residential exposure was 2.9 in 10 000, which is above the U.S. EPA's acceptable risk level. Overall, risk estimates decreased 30% when comparing results from samplers closest to active wells to those farthest. This work suggests that natural gas extraction may be contributing significantly to PAHs in air, at levels that are relevant to human health.

  4. Impact of natural gas extraction on Pah levels in ambient air

    Science.gov (United States)

    Paulik, L. Blair; Donald, Carey E.; Smith, Brian W.; Tidwell, Lane G.; Hobbie, Kevin A.; Kincl, Laurel; Haynes, Erin N.; Anderson, Kim A.

    2015-01-01

    Natural gas extraction, often referred to as “fracking,” has increased rapidly in the U.S. in recent years. To address potential health impacts, passive air samplers were deployed in a rural community heavily affected by the natural gas boom. Samplers were analyzed for 62 polycyclic aromatic hydrocarbons (PAHs). Results were grouped based on distance from each sampler to the nearest active well. PAH levels were highest when samplers were closest to active wells. Additionally, PAH levels closest to natural gas activity were an order of magnitude higher than levels previously reported in rural areas. Sourcing ratios indicate that PAHs were predominantly petrogenic, suggesting that elevated PAH levels were influenced by direct releases from the earth. Quantitative human health risk assessment estimated the excess lifetime cancer risks associated with exposure to the measured PAHs. Closest to active wells, the risk estimated for maximum residential exposure was 2.9 in 10,000, which is above the U.S. EPA's acceptable risk level. Overall, risk estimates decreased 30% when comparing results from samplers closest to active wells to those farthest. This work suggests that natural gas extraction may be contributing significantly to PAHs in air, at levels that are relevant to human health. PMID:25810398

  5. THE INFRARED SPECTROSCOPY OF NEUTRAL POLYCYCLIC AROMATIC HYDROCARBON CLUSTERS

    International Nuclear Information System (INIS)

    Ricca, Alessandra; Bauschlicher, Charles W. Jr.; Allamandola, Louis J.

    2013-01-01

    The mid-infrared spectra of neutral homogeneous polycyclic aromatic hydrocarbon (PAH) clusters have been computed using density functional theory including an empirical correction for dispersion. The C-H out-of-plane bending modes are redshifted for all the clusters considered in this work. The magnitude of the redshift and the peak broadening are dependent on PAH size, shape, and on the PAH arrangement in the cluster

  6. THE INFRARED SPECTROSCOPY OF NEUTRAL POLYCYCLIC AROMATIC HYDROCARBON CLUSTERS

    Energy Technology Data Exchange (ETDEWEB)

    Ricca, Alessandra [Carl Sagan Center, SETI Institute, 189 Bernardo Avenue, Suite 100, Mountain View, CA 94043 (United States); Bauschlicher, Charles W. Jr. [Entry Systems and Technology Division, Mail Stop 230-3, NASA Ames Research Center, Moffett Field, CA 94035 (United States); Allamandola, Louis J., E-mail: Alessandra.Ricca-1@nasa.gov, E-mail: Charles.W.Bauschlicher@nasa.gov [Space Science Division, Mail Stop 245-6, NASA Ames Research Center, Moffett Field, CA 94035 (United States)

    2013-10-10

    The mid-infrared spectra of neutral homogeneous polycyclic aromatic hydrocarbon (PAH) clusters have been computed using density functional theory including an empirical correction for dispersion. The C-H out-of-plane bending modes are redshifted for all the clusters considered in this work. The magnitude of the redshift and the peak broadening are dependent on PAH size, shape, and on the PAH arrangement in the cluster.

  7. PAHs in the Ices of Saturn's Satellites: Connections to the Solar Nebula and the Interstellar Medium

    Science.gov (United States)

    Cruikshank, Dale P.; Pendleton, Yvonne J.

    2015-01-01

    Aliphatic hydrocarbons and PAHs have been observed in the interstellar medium (e.g., Allamandola et al. 1985, Pendleton et al. 1994, Pendleton & Allamandola 2002, Tielens 2013, Kwok 2008, Chiar & Pendleton 2008) The inventory of organic material in the ISM was likely incorporated into the molecular cloud in which the solar nebula condensed, contributing to the feedstock for the formation of the Sun, major planets, and the smaller icy bodies in the region outside Neptune's orbit (transneptunian objects, or TNOs). Additional organic synthesis occurred in the solar nebula (Ciesla & Sandford 2012). Saturn's satellites Phoebe, Iapetus, and Hyperion open a window to the composition of one class of TNO as revealed by the near-infrared mapping spectrometer (VIMS) on the Cassini spacecraft at Saturn. Phoebe (mean diameter 213 km) is a former TNO now orbiting Saturn (Johnson & Lunine 2005). VIMS spectral maps of Phoebe's surface reveal a complex organic spectral signature consisting of prominent aromatic (CH) and aliphatic hydrocarbon (=CH2, -CH3) absorption bands (3.2-3.6 micrometers). Phoebe is the source of a huge debris ring encircling Saturn, and from which particles ((is) approximately 5-20 micrometers size) spiral inward toward Saturn (Verbiscer et al. 2009). They encounter Iapetus and Hyperion where they mix with and blanket the native H2O ice of those two bodies. Quantitative analysis of the hydrocarbon bands on Iapetus demonstrates that aromatic CH is approximately 10 times as abundant as aliphatic CH2+CH3, significantly exceeding the strength of the aromatic signature in interplanetary dust particles, comet particles, and in carbonaceous meteorites (Cruikshank et al. 2014). A similar excess of aromatics over aliphatics is seen in the qualitative analysis of Hyperion and Phoebe itself (Dalle Ore et al. 2012). The Iapetus aliphatic hydrocarbons show CH2/CH3 (is) approximately 4, which is larger than the value found in the diffuse ISM ((is) approximately 2

  8. PAH features within few hundred parsecs of active galactic nuclei

    Science.gov (United States)

    Jensen, J. J.; Hönig, S. F.; Rakshit, S.; Alonso-Herrero, A.; Asmus, D.; Gandhi, P.; Kishimoto, M.; Smette, A.; Tristram, K. R. W.

    2017-09-01

    Spectral features from polycyclic aromatic hydrocarbon (PAH) molecules observed in the mid-infrared (mid-IR) range are typically used to infer the amount of recent and ongoing star formation on kiloparsec scales around active galactic nuclei (AGN) where more traditional methods fail. This method assumes that the observed PAH features are excited predominantly by star formation. With current ground-based telescopes and the upcoming James Webb Space Telescope, much smaller spatial scales can be probed and we aim at testing if this assumption still holds in the range of few tens to few hundreds of parsecs. For that, we spatially map the emitted 11.3 μm PAH surface flux as a function of distance from 0.4-4 arcsec from the centre in 28 nearby AGN using ground-based high-angular-resolution mid-IR spectroscopy. We detect and extract the 11.3 μm PAH feature in 13 AGN. The fluxes within each aperture are scaled to a luminosity-normalized distance from the nucleus to be able to compare intrinsic spatial scales of AGN radiation spanning about two orders of magnitude in luminosity. For this, we establish an empirical relation between the absorption-corrected X-ray luminosity and the sublimation radius in these sources. Once normalized, the radial profiles of the emitted PAH surface flux show similar radial slopes, with a power-law index of approximately -1.1, and similar absolute values, consistent within a factor of a few of each other as expected from the uncertainty in the intrinsic scale estimate. We interpret this as evidence that the profiles are caused by a common compact central physical process, either the AGN itself or circumnuclear star formation linked in strength to the AGN power. A photoionization-based model of an AGN exciting dense clouds in its environment can reproduce the observed radial slope and confirms that the AGN radiation field is strong enough to explain the observed PAH surface fluxes within ∼10-500 pc of the nucleus. Our results advice caution

  9. Sources of polyaromatic hydrocarbons (PAH); Kildebestemmelse af polyaromatiske kulbrinter (PAH)

    Energy Technology Data Exchange (ETDEWEB)

    Egsgaard, H. [Forskningscenetr Risoe, Ald. for Plantebiologi og Biokemi (DK); Larsen, E. [Forskningscenter Risoe, Ald. for Optic og Fluid Dynamik (Denmark)

    2000-03-01

    Aromatic hydrocarbons including PAH compounds are thermally and chemically very stable compounds and are formed by gasification/pyrolysis of biomass. With reference to the tar compounds present in the produced gas from updraft gasifiers the sources responsible for the formation of naphthalene and poly-aromatic hydrocarbons have been investigated. The focus has been on thermal and oxidative conversions of compounds related to the lignin building blocks. Thus, phenols, 2-methoxy-phenols and 4-substituted-2-methoxy-phenols were investigated by introducing water solutions of the compounds into a continuos flow system operating in the temperature range 600-850 deg. C. The pyrolysis products were identified by GC/MS. The tar compounds reveal a well-defined and characteristic thermal transformation. Phenol is a strong source to naphthalene and indenes while 2-methoxyphenols are sources to aromatic oxo-compounds such as cinnamaldehyde. More complex systems are sources to higer PAH compounds. Thus, oligomers of phenol and 2-methoxyphenol give dibenzofuran and oligomers of isoeugenol are important sources to acenaphthylene. It is characteristic that the simple tar compounds investigated undergo loss of CO and hereby loss of the aromatic structure. The intermediary compounds are very reactive cyclo-pentadienes entering Diels-Alder reactions. The later products are transformed to aromatic compounds. The results may facilitate the determination of optimum conditions for updraft gasifiers and hence a reduction of PAH formation. (au)

  10. Cancer risk from incidental ingestion exposures to PAHs associated with coal-tar-sealed pavement

    Science.gov (United States)

    Williams, E. Spencer; Mahler, Barbara J.; Van Metre, Peter C.

    2012-01-01

    Recent (2009-10) studies documented significantly higher concentrations of polycyclic aromatic hydrocarbons (PAHs) in settled house dust in living spaces and soil adjacent to parking lots sealed with coal-tar-based products. To date, no studies have examined the potential human health effects of PAHs from these products in dust and soil. Here we present the results of an analysis of potential cancer risk associated with incidental ingestion exposures to PAHs in settings near coal-tar-sealed pavement. Exposures to benzo[a]pyrene equivalents were characterized across five scenarios. The central tendency estimate of excess cancer risk resulting from lifetime exposures to soil and dust from nondietary ingestion in these settings exceeded 1 × 10–4, as determined using deterministic and probabilistic methods. Soil was the primary driver of risk, but according to probabilistic calculations, reasonable maximum exposure to affected house dust in the first 6 years of life was sufficient to generate an estimated excess lifetime cancer risk of 6 × 10–5. Our results indicate that the presence of coal-tar-based pavement sealants is associated with significant increases in estimated excess lifetime cancer risk for nearby residents. Much of this calculated excess risk arises from exposures to PAHs in early childhood (i.e., 0–6 years of age).

  11. PAHs and the Diffuse Interstellar Bands. What have we Learned from the New Generation of Laboratory and Observational Studies?

    Science.gov (United States)

    Salama, Farid

    2005-01-01

    Polycyclic Aromatic Hydrocarbons (PAHs) are an important and ubiquitous component of carbon-bearing materials in space. PAHs are the best-known candidates to account for the IR emission bands (UIR bands) and PAH spectral features are now being used as new probes of the ISM. PAHs are also thought to be among the carriers of the diffuse interstellar absorption bands (DIBs). In the model dealing with the interstellar spectral features, PAHs are present as a mixture of radicals, ions and neutral species. PAH ionization states reflect the ionization balance of the medium while PAH size, composition, and structure reflect the energetic and chemical history of the medium. A major challenge for laboratory astrophysics is to reproduce (in a realistic way) the physical conditions that exist in the emission and/or absorption interstellar zones, An extensive laboratory program has been developed at NASA Ames to characterize the physical and chemical properties of PAHs in astrophysical environments and to describe how they influence the radiation and energy balance in space and the interstellar chemistry. In particular, laboratory experiments provide measurements of the spectral characteristics of interstellar PAH analogs from the ultraviolet and visible range to the infrared range for comparison with astronomical data. This paper will focus on the recent progress made in the laboratory to measure the direct absorption spectra of neutral and ionized PAHs in the gas phase in the near-W and visible range in astrophysically relevant environments. These measurements provide data on PAHs and nanometer-sized particles that can now be directly compared to astronomical observations. The harsh physical conditions of the IS medium - characterized by a low temperature, an absence of collisions and strong V W radiation fields - are simulated in the laboratory by associating a molecular beam with an ionizing discharge to generate a cold plasma expansion. PAH ions are formed from the neutral

  12. Occupational PAH Exposures during Prescribed Pile Burns

    Science.gov (United States)

    Robinson, M. S.; Anthony, T. R.; Littau, S. R.; Herckes, P.; Nelson, X.; Poplin, G. S.; Burgess, J. L.

    2008-01-01

    Wildland firefighters are exposed to particulate matter and gases containing polycyclic aromatic hydrocarbons (PAHs), many of which are known carcinogens. Our objective was to evaluate the extent of firefighter exposure to particulate and PAHs during prescribed pile burns of mainly ponderosa pine slash and determine whether these exposures were correlated with changes in urinary 1-hydroxypyrene (1-HP), a PAH metabolite. Personal and area sampling for particulate and PAH exposures were conducted on the White Mountain Apache Tribe reservation, working with 21 Bureau of Indian Affairs/Fort Apache Agency wildland firefighters during the fall of 2006. Urine samples were collected pre- and post-exposure and pulmonary function was measured. Personal PAH exposures were detectable for only 3 of 16 PAHs analyzed: naphthalene, phenanthrene, and fluorene, all of which were identified only in vapor-phase samples. Condensed-phase PAHs were detected in PM2.5 area samples (20 of 21 PAHs analyzed were detected, all but naphthalene) at concentrations below 1 μg m−3. The total PAH/PM2.5 mass fractions were roughly a factor of two higher during smoldering (1.06 ± 0.15) than ignition (0.55 ± 0.04 μg mg−1). There were no significant changes in urinary 1-HP or pulmonary function following exposure to pile burning. In summary, PAH exposures were low in pile burns, and urinary testing for a PAH metabolite failed to show a significant difference between baseline and post-exposure measurements. PMID:18515848

  13. PAHS

    African Journals Online (AJOL)

    user

    2011-03-02

    Mar 2, 2011 ... spillage's and/or heavy ship traffic. However, the ... various aspects such as industrial effluents, air, highway vehicle exhaust and highway .... detection (LOD) of the GC-MS method, established at signals three times that of the.

  14. Excess Entropy and Diffusivity

    Indian Academy of Sciences (India)

    First page Back Continue Last page Graphics. Excess Entropy and Diffusivity. Excess entropy scaling of diffusivity (Rosenfeld,1977). Analogous relationships also exist for viscosity and thermal conductivity.

  15. Influence of PAHs among other coastal environmental variables on total and PAH-degrading bacterial communities.

    Science.gov (United States)

    Sauret, Caroline; Tedetti, Marc; Guigue, Catherine; Dumas, Chloé; Lami, Raphaël; Pujo-Pay, Mireille; Conan, Pascal; Goutx, Madeleine; Ghiglione, Jean-François

    2016-03-01

    We evaluated the relative impact of anthropogenic polycyclic aromatic hydrocarbons (PAHs) among biogeochemical variables on total, metabolically active, and PAH bacterial communities in summer and winter in surface microlayer (SML) and subsurface seawaters (SSW) across short transects along the NW Mediterranean coast from three harbors, one wastewater effluent, and one nearshore observatory reference site. At both seasons, significant correlations were found between dissolved total PAH concentrations and PAH-degrading bacteria that formed a gradient from the shore to nearshore waters. Accumulation of PAH degraders was particularly high in the SML, where PAHs accumulated. Harbors and wastewater outfalls influenced drastically and in a different way the total and active bacterial community structure, but they only impacted the communities from the nearshore zone (PAH concentrations on the spatial and temporal dynamic of total and active communities in this area, but this effect was putted in perspective by the importance of other biogeochemical variables.

  16. Using deuterated PAH amendments to validate chemical extraction methods to predict PAH bioavailability in soils

    International Nuclear Information System (INIS)

    Gomez-Eyles, Jose L.; Collins, Chris D.; Hodson, Mark E.

    2011-01-01

    Validating chemical methods to predict bioavailable fractions of polycyclic aromatic hydrocarbons (PAHs) by comparison with accumulation bioassays is problematic. Concentrations accumulated in soil organisms not only depend on the bioavailable fraction but also on contaminant properties. A historically contaminated soil was freshly spiked with deuterated PAHs (dPAHs). dPAHs have a similar fate to their respective undeuterated analogues, so chemical methods that give good indications of bioavailability should extract the fresh more readily available dPAHs and historic more recalcitrant PAHs in similar proportions to those in which they are accumulated in the tissues of test organisms. Cyclodextrin and butanol extractions predicted the bioavailable fraction for earthworms (Eisenia fetida) and plants (Lolium multiflorum) better than the exhaustive extraction. The PAHs accumulated by earthworms had a larger dPAH:PAH ratio than that predicted by chemical methods. The isotope ratio method described here provides an effective way of evaluating other chemical methods to predict bioavailability. - Research highlights: → Isotope ratios can be used to evaluate chemical methods to predict bioavailability. → Chemical methods predicted bioavailability better than exhaustive extractions. → Bioavailability to earthworms was still far from that predicted by chemical methods. - A novel method using isotope ratios to assess the ability of chemical methods to predict PAH bioavailability to soil biota.

  17. Using deuterated PAH amendments to validate chemical extraction methods to predict PAH bioavailability in soils

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Eyles, Jose L., E-mail: j.l.gomezeyles@reading.ac.uk [University of Reading, School of Human and Environmental Sciences, Soil Research Centre, Reading, RG6 6DW Berkshire (United Kingdom); Collins, Chris D.; Hodson, Mark E. [University of Reading, School of Human and Environmental Sciences, Soil Research Centre, Reading, RG6 6DW Berkshire (United Kingdom)

    2011-04-15

    Validating chemical methods to predict bioavailable fractions of polycyclic aromatic hydrocarbons (PAHs) by comparison with accumulation bioassays is problematic. Concentrations accumulated in soil organisms not only depend on the bioavailable fraction but also on contaminant properties. A historically contaminated soil was freshly spiked with deuterated PAHs (dPAHs). dPAHs have a similar fate to their respective undeuterated analogues, so chemical methods that give good indications of bioavailability should extract the fresh more readily available dPAHs and historic more recalcitrant PAHs in similar proportions to those in which they are accumulated in the tissues of test organisms. Cyclodextrin and butanol extractions predicted the bioavailable fraction for earthworms (Eisenia fetida) and plants (Lolium multiflorum) better than the exhaustive extraction. The PAHs accumulated by earthworms had a larger dPAH:PAH ratio than that predicted by chemical methods. The isotope ratio method described here provides an effective way of evaluating other chemical methods to predict bioavailability. - Research highlights: > Isotope ratios can be used to evaluate chemical methods to predict bioavailability. > Chemical methods predicted bioavailability better than exhaustive extractions. > Bioavailability to earthworms was still far from that predicted by chemical methods. - A novel method using isotope ratios to assess the ability of chemical methods to predict PAH bioavailability to soil biota.

  18. Chemical and bioanalytical characterisation of PAHs in risk assessment of remediated PAH-contaminated soils.

    Science.gov (United States)

    Larsson, Maria; Hagberg, Jessika; Rotander, Anna; van Bavel, Bert; Engwall, Magnus

    2013-12-01

    Polycyclic aromatic hydrocarbons (PAHs) are common contaminants in soil at former industrial areas; and in Sweden, some of the most contaminated sites are being remediated. Generic guideline values for soil use after so-called successful remediation actions of PAH-contaminated soil are based on the 16 EPA priority pollutants, which only constitute a small part of the complex cocktail of toxicants in many contaminated soils. The aim of the study was to elucidate if the actual toxicological risks of soil samples from successful remediation projects could be reflected by chemical determination of these PAHs. We compared chemical analysis (GC-MS) and bioassay analysis (H4IIE-luc) of a number of remediated PAH-contaminated soils. The H4IIE-luc bioassay is an aryl hydrocarbon (Ah) receptor-based assay that detects compounds that activate the Ah receptor, one important mechanism for PAH toxicity. Comparison of the results showed that the bioassay-determined toxicity in the remediated soil samples could only be explained to a minor extent by the concentrations of the 16 priority PAHs. The current risk assessment method for PAH-contaminated soil in use in Sweden along with other countries, based on chemical analysis of selected PAHs, is missing toxicologically relevant PAHs and other similar substances. It is therefore reasonable to include bioassays in risk assessment and in the classification of remediated PAH-contaminated soils. This could minimise environmental and human health risks and enable greater safety in subsequent reuse of remediated soils.

  19. From the Laboratory to Space: Neutral and Ionized PAHs in Translucent Interstellar Clouds

    Science.gov (United States)

    Salama, Farid; Galazutdinov, G.; Biennier, L.; Krelowski, J.

    2012-05-01

    We describe and discuss the laboratory experiments that were designed to test the proposal of relating the origin of some of the diffuse interstellar bands (DIBs) to neutral and ionized polycyclic aromatic hydrocarbons (PAHs) present in diffuse interstellar clouds. The spectra of several cold, isolated gas-phase PAH ions and neutral molecules have been measured using the COSmIC laboratory facility at NASA-Ames and are compared with an extensive set of astronomical spectra of reddened, early type stars. The COSmIC facility combines a supersonic free jet expansion with discharge plasma and high-sensitivity cavity ringdown spectroscopy to provide experimental conditions that closely mimic the interstellar conditions. This comparison provides - for the first time - accurate upper limits for the abundances of specific PAH molecules and ions along specific lines-of-sight. Something that is not attainable from infrared observations alone. The comparison of these unique laboratory data with high resolution, high S/N ratio astronomical observations leads to major findings regarding the column densities of the individual PAH molecules and ions that are probed in this survey and leads to clear and unambiguous conclusions regarding the expected abundances for PAHs of various sizes and charge states in these environments. This quantitative survey of neutral and ionized PAHs in the optical range opens the way for unambiguous quantitative searches of PAHs and complex organics in a variety of interstellar and circumstellar environments. Acknowledgements: F.S. acknowledges the support of the NASA’s Space Mission Directorate APRA Program. The authors are deeply grateful to the ESO archive as well as to the ESO staff members for their active support.

  20. IRAS surface brightness maps of visible reflection nebulae: evidence for non-equilibrium infrared emission

    International Nuclear Information System (INIS)

    Castelaz, M.W.; Werner, M.W.; Sellgren, K.

    1986-01-01

    Surface brightness maps at 12, 25, 60, and 100 microns of 16 visible reflection nebulae were extracted from the Infrared Astronomy Satellite (IRAS) database. The maps were produced by coadding IRAS survey scans over areas centered on the illuminating stars, and have spatial resolutions of 0.9' x 4' at 12 and 25 microns, 1.8' x 4.5' at 60 microns, and 3.6' x 5' at 100 microns. Extended emission in the four IRAS bandpasses was detected in fourteen of the reflection nebulae. The IRAS data were used to measure the flux of the infrared emission associated with each source. The energy distributions show that the 12 micron flux is greater than the 25 micron flux in 11 of the nebulae, and the peak flux occurs in the 60 or 100 micron bandpass in all 16 nebular. The 60 and 100 micron flux can be approximated by blackbodies with temperatures between 30 and 50 K, consistent with temperatures expected from extrapolation of greybody fits to the 60 and 100 micron data. The excess 12 and 25 micron emission is attributed to a nonequilibrium process such as emission from thermal fluctuations of very small grains excited by single ultraviolet photons, or emission from polycyclic aromatic hydrocarbons (PAHs) excited by ultraviolet radiation. The common features of the energy distributions of the 16 reflection nebulae, also seen in the reflection nebulae associated with the Pleiades, suggest that PAHs or very small grains may be found in most reflection nebulae

  1. Urban sprawl leaves its PAH signature

    Science.gov (United States)

    Van Metre, P.C.; Mahler, B.J.; Furlong, E.T.

    2000-01-01

    The increasing vehicle traffic associated with urban sprawl in the United States is frequently linked to degradation of air quality, but its effect on aquatic sediment is less well-recognized. This study evaluates trends in PAHs, a group of contaminants with multiple urban sources, in sediment cores from 10 reservoirs and lakes in six U.S. metropolitan areas. The watersheds chosen represent a range in degree and age of urbanization. Concentrations of PAHs in all 10 reservoirs and lakes increased during the past 20-40 years. PAH contamination of the most recently deposited sediment at all sites exceeded sediment-quality guidelines established by Environment Canada, in some cases by several orders of magnitude. These results add a new chapter to the story told by previous coring studies that reported decreasing concentrations of PAHs after reaching highs in the 1950s. Concurrent with the increase in concentrations is a change in the assemblage of PAHs that indicates the increasing trends are driven by combustion sources. The increase in PAH concentrations tracks closely with increases in automobile use, even in watersheds that have not undergone substantial changes in urban land-use levels since the 1970s.The increasing vehicle traffic associated with urban sprawl in the United States is frequently linked to degradation of air quality, but its effect on aquatic sediment is less well-recognized. This study evaluates trends in PAHs, a group of contaminants with multiple urban sources, in sediment cores from 10 reservoirs and lakes in six U.S. metropolitan areas. The watersheds chosen represent a range in degree and age of urbanization. Concentrations of PAHs in all 10 reservoirs and lakes increased during the past 20-40 years. PAH contamination of the most recently deposited sediment at all sites exceeded sediment-quality guidelines established by Environment Canada, in some cases by several orders of magnitude. These results add a new chapter to the story told by

  2. A PAH growth mechanism and synergistic effect on PAH formation in counterflow diffusion flames

    KAUST Repository

    Wang, Yu

    2013-09-01

    A reaction mechanism having molecular growth up to benzene for hydrocarbon fuels with up to four carbon-atoms was extended to include the formation and growth of polycyclic aromatic hydrocarbons (PAHs) up to coronene (C24H12). The new mechanism was tested for ethylene premixed flames at low (20torr) and atmospheric pressures by comparing experimentally observed species concentrations with those of the computed ones for small chemical species and PAHs. As compared to several existing mechanisms in the literature, the newly developed mechanism showed an appreciable improvement in the predicted profiles of PAHs. The new mechanism was also used to simulate PAH formation in counterflow diffusion flames of ethylene to study the effects of mixing propane and benzene in the fuel stream. In the ethylene-propane flames, existing experimental results showed a synergistic effect in PAH concentrations, i.e. PAH concentrations first increased and then decreased with increasing propane mixing. This PAH behavior was successfully captured by the new mechanism. The synergistic effect was predicted to be more pronounced for larger PAH molecules as compared to the smaller ones, which is in agreement with experimental observations. In the experimental study in which the fuel stream of ethylene-propane flames was doped with benzene, a synergistic effect was mitigated for benzene, but was observed for large PAHs. This effect was also predicted in the computed PAH profiles for these flames. To explain these responses of PAHs in the flames of mixture fuels, a pathway analysis has been conducted, which show that several resonantly stabilized species as well as C4H4 and H atom contribute to the enhanced synergistic behaviors of larger PAHs as compared to the small ones in the flames of mixture fuels. © 2013 The Combustion Institute.

  3. Polysykliske aromatiske hydrokarboner (PAH) i fisk

    OpenAIRE

    Knutzen, J.

    1987-01-01

    Det er sammenstilt litteraturdata om polysykliske aromatiske hydrokarboner (PAH, tjærestoffer) i fisk fra et lite påvirkede og fra forurensede områder og sammenlignet med utvalgte data for PAH i røkt fisk. På grunn av sparsomt og delvis tvilsomt materiale, har det bare latt seg gjøre å antyde øvre grense for et "diffust bakgrunnsnivå" av benzo(a)pyren i fiskefilet: 1 µg/kg frisk vekt. Ofte har ikke total-PAH eller utvalgte PAH-forbindelser latt seg påvise, selv i områder som vites å være mark...

  4. Determination of polynuclear aromatic hydrocarbons (PAHs) in ...

    African Journals Online (AJOL)

    AJB SERVER

    2006-11-02

    Nov 2, 2006 ... Several water bodies in the Niger Delta region of Nigeria where extensive crude oil ..... hydrocarbons (PAHs) in fish from the Red Sea Coast of Yemem. ... smoked meat products and smoke flavouring food additives. J.

  5. Properties of polycyclic aromatic hydrocarbons in the northwest photon dominated region OF NGC 7023. I. PAH size, charge, composition, and structure distribution

    International Nuclear Information System (INIS)

    Boersma, C.; Bregman, J. D.; Allamandola, L. J.

    2013-01-01

    Polycyclic aromatic hydrocarbon (PAH) emission in the Spitzer Infrared Spectrograph spectral map of the northwest photon dominated region (PDR) in NGC 7023 was analyzed exclusively using PAH spectra from the NASA Ames PAH IR Spectroscopic Database (www.astrochem.org/pahdb). The 5-15 μm spectrum at each pixel is fitted using a non-negative-least-squares fitting approach. The fits are of good quality, allowing decomposition of the PAH emission into four subclasses: size, charge, composition, and hydrogen adjacency (structure). Maps tracing PAH subclass distributions across the region paint a coherent astrophysical picture. Once past some 20 seconds of arc from HD 200775, the emission is dominated by the more stable, large, symmetric, compact PAH cations with smaller, neutral PAHs taking over along the lines-of-sight toward the more distant molecular cloud. The boundary between the PDR and the denser cloud material shows up as a distinct discontinuity in the breakdown maps. Noteworthy is the requirement for PANH cations to fit the bulk of the 6.2 and 11.0 μm features and the indication of PAH photo-dehydrogenation and fragmentation close to HD 200775. Decomposition of the spectral maps into 'principal' subclass template spectra provides additional insight into the behavior of each subclass. However, the general applicability of this computationally more efficient approach is presently undetermined. This is the first time the spectra of individual PAHs are exclusively used to fit the 5-15 μm region and analyze the spatial behavior of the aromatic infrared bands, providing fundamental, new information about astronomical PAH subpopulations including their dependence on, and response to, changes in local conditions.

  6. Properties of polycyclic aromatic hydrocarbons in the northwest photon dominated region OF NGC 7023. I. PAH size, charge, composition, and structure distribution

    Energy Technology Data Exchange (ETDEWEB)

    Boersma, C.; Bregman, J. D.; Allamandola, L. J., E-mail: Christiaan.Boersma@nasa.gov [NASA Ames Research Center, MS 245-6, Moffett Field, CA 94035-0001 (United States)

    2013-06-01

    Polycyclic aromatic hydrocarbon (PAH) emission in the Spitzer Infrared Spectrograph spectral map of the northwest photon dominated region (PDR) in NGC 7023 was analyzed exclusively using PAH spectra from the NASA Ames PAH IR Spectroscopic Database (www.astrochem.org/pahdb). The 5-15 μm spectrum at each pixel is fitted using a non-negative-least-squares fitting approach. The fits are of good quality, allowing decomposition of the PAH emission into four subclasses: size, charge, composition, and hydrogen adjacency (structure). Maps tracing PAH subclass distributions across the region paint a coherent astrophysical picture. Once past some 20 seconds of arc from HD 200775, the emission is dominated by the more stable, large, symmetric, compact PAH cations with smaller, neutral PAHs taking over along the lines-of-sight toward the more distant molecular cloud. The boundary between the PDR and the denser cloud material shows up as a distinct discontinuity in the breakdown maps. Noteworthy is the requirement for PANH cations to fit the bulk of the 6.2 and 11.0 μm features and the indication of PAH photo-dehydrogenation and fragmentation close to HD 200775. Decomposition of the spectral maps into 'principal' subclass template spectra provides additional insight into the behavior of each subclass. However, the general applicability of this computationally more efficient approach is presently undetermined. This is the first time the spectra of individual PAHs are exclusively used to fit the 5-15 μm region and analyze the spatial behavior of the aromatic infrared bands, providing fundamental, new information about astronomical PAH subpopulations including their dependence on, and response to, changes in local conditions.

  7. Properties of Polycyclic Aromatic Hydrocarbons in the Northwest Photon Dominated Region of NGC 7023. I. PAH Size, Charge, Composition, and Structure Distribution

    Science.gov (United States)

    Boersma, C.; Bregman, Jesse; Allamandola, L. J

    2013-01-01

    Polycyclic aromatic hydrocarbon (PAH) emission in the Spitzer Infrared Spectrograph spectral map of the northwest photon dominated region (PDR) in NGC 7023 was analyzed exclusively using PAH spectra from the NASA Ames PAH IR Spectroscopic Database (www.astrochem.org/pahdb). The 5-15 micron spectrum at each pixel is fitted using a non-negative-least-squares fitting approach. The fits are of good quality, allowing decomposition of the PAH emission into four subclasses: size, charge, composition, and hydrogen adjacency (structure). Maps tracing PAH subclass distributions across the region paint a coherent astrophysical picture. Once past some 20 seconds of arc from HD 200775, the emission is dominated by the more stable, large, symmetric, compact PAH cations with smaller, neutral PAHs taking over along the lines-of-sight toward the more distant molecular cloud. The boundary between the PDR and the denser cloud material shows up as a distinct discontinuity in the breakdown maps. Noteworthy is the requirement for PANH cations to fit the bulk of the 6.2 and 11.0 micron features and the indication of PAH photo-dehydrogenation and fragmentation close to HD 200775. Decomposition of the spectral maps into "principal" subclass template spectra provides additional insight into the behavior of each subclass. However, the general applicability of this computationally more efficient approach is presently undetermined. This is the first time the spectra of individual PAHs are exclusively used to fit the 5-15 micron region and analyze the spatial behavior of the aromatic infrared bands, providing fundamental, new information about astronomical PAH subpopulations including their dependence on, and response to, changes in local conditions.

  8. Analysis of PAH in soil samples

    International Nuclear Information System (INIS)

    Haeufel, J.; Weisweiler, W.

    1994-01-01

    The supercritical fluid extraction of polycyclic aromatic hydrocarbons (PAH) from soil samples is described. Carbon dioxide mixed with a small amount of methanol is used for solvent. The results are compared with those obtained by a classical extraction method (that means with the use of organic liquids). The extracted PAH from both procedures can be separated by HPLC and analyzed with UV- and fluorescence detection. (orig.) [de

  9. Effects of low concentration biodiesel blends application on modern passenger cars. Part 3: Impact on PAH, nitro-PAH, and oxy-PAH emissions

    International Nuclear Information System (INIS)

    Karavalakis, Georgios; Fontaras, Georgios; Ampatzoglou, Dimitrios; Kousoulidou, Marina; Stournas, Stamoulis; Samaras, Zissis; Bakeas, Evangelos

    2010-01-01

    This study explores the impact of five different types of methyl esters on polycyclic aromatic hydrocarbon (PAH), nitrated-PAH and oxygenated PAH emissions. The measurements were conducted on a chassis dynamometer, according to the European regulation. Each of the five different biodiesels was blended with EN590 diesel at a proportion of 10-90% v/v (10% biodiesel concentration). The vehicle was a Euro 3 compliant common-rail diesel passenger car. Emission measurements were performed over the NEDC and compared with those of the real traffic-based Artemis driving cycles. The experimental results showed that the addition of biodiesel led to some important increases in low molecular-weight PAHs (phenanthrene and anthracene) and to both increases and reductions in large PAHs which are characterised by their carcinogenic and mutagenic properties. Nitro-PAHs were found to reduce with biodiesel whereas oxy-PAH emissions presented important increases with the biodiesel blends. The impact of biodiesel source material was particularly clear on the formation of PAH compounds. It was found that most PAH emissions decreased as the average load and speed of the driving cycle increased. Cold-start conditions negatively influenced the formation of most PAH compounds. A similar trend was observed with particulate alkane emissions. - This investigation is a contribution to the understanding the impact of different biodiesels on the formation of PAHs, nitro-PAHs and oxy-PAHs over different driving conditions.

  10. A search for PAHs in the ISO spectra of comet Hale-Bopp

    Science.gov (United States)

    Crovisier, J.; Bockelée-Morvan, D.

    2007-12-01

    From a new analysis of a spectrum of comet C/1995 O1 (Hale-Bopp) obtained with the Infrared Space Observatory (ISO), Lisse et al. (2007) claimed the identification of many new dust species. Among them are PAHs, which were not found in our first analysis of the ISO spectra. We present a re-examination of the ISO observations of comet Hale-Bopp, which does not confirm the conclusion of Lisse et al.

  11. Infrared Astronomy and Star Formation

    International Nuclear Information System (INIS)

    Evans, N.J.

    1985-01-01

    Infrared astronomy is a natural tool to use in studying star formation because infrared light penetrates the surrounding dust and because protostars are expected to emit infrared light. Infrared mapping and photometry have revealed many compact sources, often embedded in more extensive warm dust associated with a molecular cloud core. More detailed study of these objects is now beginning, and traditional interpretations are being questioned. Some compact sources are now thought to be density enhancements which are not self-luminous. Infrared excesses around young stars may not always be caused by circumstellar dust; speckle measurements have shown that at least some of the excess toward T Tauri is caused by an infrared companion. Spectroscopic studies of the dense, star-forming cores and of the compact objects themselves have uncovered a wealth of new phenomena, including the widespread occurence of energetic outflows. New discoveries with IRAS and with other planned infrared telescopes will continue to advance this field. (author)

  12. The NASA Ames Polycyclic Aromatic Hydrocarbon Infrared Spectroscopic Database : The Computed Spectra

    NARCIS (Netherlands)

    Bauschlicher, C. W.; Boersma, C.; Ricca, A.; Mattioda, A. L.; Cami, J.; Peeters, E.; de Armas, F. Sanchez; Saborido, G. Puerta; Hudgins, D. M.; Allamandola, L. J.

    The astronomical emission features, formerly known as the unidentified infrared bands, are now commonly ascribed to polycyclic aromatic hydrocarbons (PAHs). The laboratory experiments and computational modeling done at the NASA Ames Research Center to create a collection of PAH IR spectra relevant

  13. Research on the influence of anaerobic stabilization of various dairy sewage sludge on biodegradation of polycyclic aromatic hydrocarbons PAHs with the use of effective microorganisms

    International Nuclear Information System (INIS)

    Boruszko, Dariusz

    2017-01-01

    Sewage sludge was taken from a dairy WWTP belonging to Mlekovita Cooperative in Wysokie Mazowieckie. There were excess sludge, flotation sludge and a mixture of excess and flotation sludge from pre-treatment of dairy sewage. The initial content of 16 PAHs in excess sludge before fermentation was approximately 689 µg·kg −1 in dry mass, whereas in post-flotation sludge (which constituted around 30% of raw sludge) it was approximately 95 µg·kg −1 in dry mass. A mixture of excess and flotation sludge had the content of 497,7 µg·kg −1 in dry mass. Through comparison of particular hydrocarbons content in raw sewage sludge to the total PAHs content, it was shown that tricyclic compounds, which constituted 46,3% of the PAHs sum (excess sludge), and tetracyclic compounds, which constituted 60,0% of the PAHs sum (flotation sludge), were the dominating fractions. In the sludge subjected to fermentation in reactors with mixed sludge and surplus activated sludge, the general trend of the course of changes in concentrations of PAHs was similar. Both in the sludge inoculated with EM and in that not inoculated with EM, a significant increase in the total PAHs contents was observed in the first fermentation phase (acidic fermentation) after 7 days of the process. Addition of EM into the sludge did not prevent the PAHs release, and therefore higher concentrations of PAHs sum were recorded during the hydrolysis stage than in sludge before fermentation. A decrease in the sum of PAHs was observed after 2 weeks of fermentation in relation to the quantity observed after 1 week of fermentation (except from post-flotation sludge). In the following weeks, there was further decrease in the concentration of the 16 PAHs sum in all sludge types. However, in sludge without EM inoculation, it was lower than in sludge with EM inoculation. The loss of the majority of tested hydrocarbons was reported in the final phase of fermentation. - Highlights: • The influence of applying

  14. Research on the influence of anaerobic stabilization of various dairy sewage sludge on biodegradation of polycyclic aromatic hydrocarbons PAHs with the use of effective microorganisms

    Energy Technology Data Exchange (ETDEWEB)

    Boruszko, Dariusz, E-mail: d.boruszko@pb.edu.pl

    2017-05-15

    Sewage sludge was taken from a dairy WWTP belonging to Mlekovita Cooperative in Wysokie Mazowieckie. There were excess sludge, flotation sludge and a mixture of excess and flotation sludge from pre-treatment of dairy sewage. The initial content of 16 PAHs in excess sludge before fermentation was approximately 689 µg·kg{sup −1} in dry mass, whereas in post-flotation sludge (which constituted around 30% of raw sludge) it was approximately 95 µg·kg{sup −1} in dry mass. A mixture of excess and flotation sludge had the content of 497,7 µg·kg{sup −1} in dry mass. Through comparison of particular hydrocarbons content in raw sewage sludge to the total PAHs content, it was shown that tricyclic compounds, which constituted 46,3% of the PAHs sum (excess sludge), and tetracyclic compounds, which constituted 60,0% of the PAHs sum (flotation sludge), were the dominating fractions. In the sludge subjected to fermentation in reactors with mixed sludge and surplus activated sludge, the general trend of the course of changes in concentrations of PAHs was similar. Both in the sludge inoculated with EM and in that not inoculated with EM, a significant increase in the total PAHs contents was observed in the first fermentation phase (acidic fermentation) after 7 days of the process. Addition of EM into the sludge did not prevent the PAHs release, and therefore higher concentrations of PAHs sum were recorded during the hydrolysis stage than in sludge before fermentation. A decrease in the sum of PAHs was observed after 2 weeks of fermentation in relation to the quantity observed after 1 week of fermentation (except from post-flotation sludge). In the following weeks, there was further decrease in the concentration of the 16 PAHs sum in all sludge types. However, in sludge without EM inoculation, it was lower than in sludge with EM inoculation. The loss of the majority of tested hydrocarbons was reported in the final phase of fermentation. - Highlights: • The influence of

  15. Abundances of Neutral and Ionized PAH Along The Lines-of-Sight of Diffuse and Translucent Interstellar Clouds

    Science.gov (United States)

    Salama, Farid; Galazutdinov, Gazinur; Krewloski, Jacek; Biennier, Ludovic; Beletsky, Yuri; Song, In-Ok

    2013-01-01

    The spectra of neutral and ionized PAHs isolated in the gas phase at low temperature have been measured in the laboratory under conditions that mimic interstellar conditions and are compared with a set of astronomical spectra of reddened, early type stars. The comparisons of astronomical and laboratory data provide upper limits for the abundances of neutral PAH molecules and ions along specific lines-of-sight. Something that is not attainable from infrared observations. We present the characteristics of the laboratory facility (COSmIC) that was developed for this study and discuss the findings resulting from the comparison of the laboratory data with high resolution, high S/N ratio astronomical observations. COSmIC combines a supersonic jet expansion with discharge plasma and cavity ringdown spectroscopy and provides experimental conditions that closely mimic the interstellar conditions. The column densities of the individual PAH molecules and ions probed in these surveys are derived from the comparison of the laboratory data with high resolution, high S/N ratio astronomical observations. The comparisons of astronomical and laboratory data lead to clear conclusions regarding the expected abundances for PAHs in the interstellar environments probed in the surveys. Band profile comparisons between laboratory and astronomical spectra lead to information regarding the molecular structures and characteristics associated with the DIB carriers in the corresponding lines-of-sight. These quantitative surveys of neutral and ionized PAHs in the optical range open the way for quantitative searches of PAHs and complex organics in a variety of interstellar and circumstellar environments.

  16. Composition and morphology characterization of exopolymeric substances produced by the PAH-degrading fungus of Mucor mucedo.

    Science.gov (United States)

    Jia, Chunyun; Li, Xiaojun; Allinson, Graeme; Liu, Changfeng; Gong, Zongqiang

    2016-05-01

    To explore the role of exopolymeric substances (EPS) in the process of polycyclic aromatic hydrocarbons (PAH) biodegradation, the characteristics of EPS isolated from a PAH-degrading fungus were investigated firstly by spectrometric determination, microscopic observation, Fourier transform-infrared spectroscopy (FT-IR), and three-dimensional excitation-emission matrix fluorescence spectroscopy (3D-EEM), and then the PAH-degrading ability of isolated EPS was evaluated. The EPS compositions and morphology varied significantly with the extraction methods. EPS were mainly composed of proteins, carbohydrate, and humic-like substances, and the cation exchange resin (CER)-extracted EPS were granular while other EPS samples were all powders. Heating was the most effective treatment method, followed by the CER, centrifugation, and ultrasonication methods. However, 3D-EEM data demonstrated that heating treatment makes the mycelia lyse the most. Overall, therefore, the CER was the best EPS extraction method for Mucor mucedo (M. mucedo). The PAH degradation results indicated that 87 % of pyrene and 81 % of benzo[a]pyrene (B[a]P) were removed by M. mucedo over 12 days and 9 % more pyrene and 7 % more B[a]P were reduced after CER-extracted EPS addition of 465 mg l(-1). The investigation of EPS characterization and EPS enhancing PAH biodegradation is the premise for further in-depth exploration of the role of EPS contribution to PAH biodegradation.

  17. Excessive Daytime Sleepiness

    Directory of Open Access Journals (Sweden)

    Yavuz Selvi

    2016-06-01

    Full Text Available Excessive daytime sleepiness is one of the most common sleep-related patient symptoms, with preva-lence in the community estimated to be as high as 18%. Patients with excessive daytime sleepiness may exhibit life threatening road and work accidents, social maladjustment, decreased academic and occupational performance and have poorer health than comparable adults. Thus, excessive daytime sleepiness is a serious condition that requires investigation, diagnosis and treatment primarily. As with most medical condition, evaluation of excessive daytime sleepiness begins a precise history and various objective and subjective tools have been also developed to assess excessive daytime sleepiness. The most common causes of excessive daytime sleepiness are insufficient sleep hygiene, chronic sleep deprivation, medical and psychiatric conditions and sleep disorders, such as obstructive sleep apnea, medications, and narcolepsy. Treatment option should address underlying contributors and promote sleep quantity by ensuring good sleep hygiene. [Psikiyatride Guncel Yaklasimlar - Current Approaches in Psychiatry 2016; 8(2: 114-132

  18. Do 16 Polycyclic Aromatic Hydrocarbons Represent PAH Air Toxicity?

    Science.gov (United States)

    Samburova, Vera; Zielinska, Barbara; Khlystov, Andrey

    2017-08-15

    Estimation of carcinogenic potency based on analysis of 16 polycyclic aromatic hydrocarbons (PAHs) ranked by U.S. Environmental Protection Agency (EPA) is the most popular approach within scientific and environmental air quality management communities. The majority of PAH monitoring projects have been focused on particle-bound PAHs, ignoring the contribution of gas-phase PAHs to the toxicity of PAH mixtures in air samples. In this study, we analyzed the results of 13 projects in which 88 PAHs in both gas and particle phases were collected from different sources (biomass burning, mining operation, and vehicle emissions), as well as in urban air. The aim was to investigate whether 16 particle-bound U.S. EPA priority PAHs adequately represented health risks of inhalation exposure to atmospheric PAH mixtures. PAH concentrations were converted to benzo(a)pyrene-equivalent (BaPeq) toxicity using the toxic equivalency factor (TEF) approach. TEFs of PAH compounds for which such data is not available were estimated using TEFs of close isomers. Total BaPeq toxicities (∑ 88 BaPeq) of gas- and particle-phase PAHs were compared with BaPeq toxicities calculated for the 16 particle-phase EPA PAH (∑ 16EPA BaPeq). The results showed that 16 EPA particle-bound PAHs underrepresented the carcinogenic potency on average by 85.6% relative to the total (gas and particle) BaPeq toxicity of 88 PAHs. Gas-phase PAHs, like methylnaphthalenes, may contribute up to 30% of ∑ 88 BaPeq. Accounting for other individual non-EPA PAHs (i.e., benzo(e)pyrene) and gas-phase PAHs (i.e., naphthalene, 1- and 2-methylnaphthalene) will make the risk assessment of PAH-containing air samples significantly more accurate.

  19. Phyto remediation of PAH contaminated soil

    International Nuclear Information System (INIS)

    Petruzzelli, G.; Pedron, F.; Barbafieri, M.; Cervelli, St.; Vigna Guidi, G.

    2005-01-01

    Phyto-remediation may enhance degradation of organic compounds promoting an adequate substrate for microbial growth. The aim of this work was to evaluate the efficiency of two plant species, Lupinus albus and Zea mais, in the bio-remediation of a PAH contaminated soil. This soil has been collected in a contaminated industrial area in Italy characterized by PAH concentrations up to 16000 mg/Kg. Microcosms experiments were carried out by planting Lupinus albus and Zea mais in the polluted soil; controls without plants were run separately. Growing period lasted by three months. Plants favoured PAH biodegradation by percentages of 32% with Lupinus albus and 22% with Zea mais, with respect to non vegetated microcosms. (authors)

  20. Effect of rhamnolipids on the uptake of PAHs by ryegrass

    International Nuclear Information System (INIS)

    Zhu Lizhong; Zhang Ming

    2008-01-01

    A hydroponic experiment was conducted to investigate the effect of rhamnolipids, a biosurfactant, on the uptake of polycyclic aromatic hydrocarbons (PAHs) by ryegrass. Results showed that rhamnolipids could enhance the uptake of PAHs by ryegrass roots. With increasing concentration of rhamnolipids, the PAH content in ryegrass roots initially increased and then decreased, while the PAH content in ryegrass shoots did not change. Batch studies also showed that the sorption of phenanthrene by fresh ryegrass roots was dependent on rhamnolipid concentration and showed the same trends as the uptake experiment. The increase of permeability of ryegrass root cells with the increase of rhamnolipid concentration may lead to the initial enhancement of PAH content in ryegrass roots, and the decrease of PAH adsorption onto the root surface with further increase of rhamnolipids led to the decrease of PAH content in ryegrass roots. - Rhamnolipids, a biosurfactant, can promote the uptake of PAHs by ryegrass, which indicates a potential application of surfactant-enhanced phytoremediation

  1. Effect of rhamnolipids on the uptake of PAHs by ryegrass

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Lizhong [Department of Environmental Science, Zhejiang University, Hangzhou, Zhejiang 310028 (China); Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, Zhejiang University, Hangzhou, Zhejiang 310029 (China)], E-mail: zlz@zju.edu.cn; Zhang Ming [Department of Environmental Science, Zhejiang University, Hangzhou, Zhejiang 310028 (China)], E-mail: zhangming@zju.edu.cn

    2008-11-15

    A hydroponic experiment was conducted to investigate the effect of rhamnolipids, a biosurfactant, on the uptake of polycyclic aromatic hydrocarbons (PAHs) by ryegrass. Results showed that rhamnolipids could enhance the uptake of PAHs by ryegrass roots. With increasing concentration of rhamnolipids, the PAH content in ryegrass roots initially increased and then decreased, while the PAH content in ryegrass shoots did not change. Batch studies also showed that the sorption of phenanthrene by fresh ryegrass roots was dependent on rhamnolipid concentration and showed the same trends as the uptake experiment. The increase of permeability of ryegrass root cells with the increase of rhamnolipid concentration may lead to the initial enhancement of PAH content in ryegrass roots, and the decrease of PAH adsorption onto the root surface with further increase of rhamnolipids led to the decrease of PAH content in ryegrass roots. - Rhamnolipids, a biosurfactant, can promote the uptake of PAHs by ryegrass, which indicates a potential application of surfactant-enhanced phytoremediation.

  2. A PAH growth mechanism and synergistic effect on PAH formation in counterflow diffusion flames

    KAUST Repository

    Wang, Yu; Raj, Abhijeet Dhayal; Chung, Suk-Ho

    2013-01-01

    was tested for ethylene premixed flames at low (20torr) and atmospheric pressures by comparing experimentally observed species concentrations with those of the computed ones for small chemical species and PAHs. As compared to several existing mechanisms

  3. Polycyclic Aromatic Hydrocarbons (PAHs) Levels in Two ...

    African Journals Online (AJOL)

    Polycyclic aromatic hydrocarbons (PAHs) concentrations were measured by gas chromatography with flame ionization detector (GC/FID) in two fish species, Sardinella maderensis (Flat sardinella) and Galeoides decadactylus (Lesser African threadfin or Shine-nose or Common threadfin) from Ghanaian coastal waters and ...

  4. Determination of polynuclear aromatic hydrocarbons (PAHs) in ...

    African Journals Online (AJOL)

    AJB SERVER

    2006-11-02

    Nov 2, 2006 ... (PAHs) in selected water bodies in the Niger Delta. Chimezie Anyakora and ... production, foundries), transportation, burning (e.g. forest, straw, agriculture ..... the Red Sea Coast of Yemen (DouAbul et al., 1997), a comparable ...

  5. Lung cancer risk in relation to traffic-related nano/ultrafine particle-bound PAHs exposure: a preliminary probabilistic assessment.

    Science.gov (United States)

    Liao, Chung-Min; Chio, Chia-Pin; Chen, Wei-Yu; Ju, Yun-Ru; Li, Wen-Hsuan; Cheng, Yi-Hsien; Liao, Vivian Hsiu-Chuan; Chen, Szu-Chieh; Ling, Min-Pei

    2011-06-15

    Exposures to carcinogenic polycyclic aromatic hydrocarbons (PAHs) have been linked to human lung cancer. The purpose of this study was to assess lung cancer risk caused by inhalation exposure to nano/ultrafine particle-bound PAHs at the population level in Taiwan appraised with recent published data. A human respiratory tract model was linked with a physiologically based pharmacokinetic model to estimate deposition fraction and internal organic-specific PAHs doses. A probabilistic risk assessment framework was developed to estimate potential lung cancer risk. We reanalyzed particle size distribution, total-PAHs, particle-bound benzo(a)pyrene (B[a]P) and PM concentrations. A dose-response profile describing the relationships between external B[a]P concentration and lung cancer risk response was constructed based on population attributable fraction (PAF). We found that 90% probability lung cancer risks ranged from 10(-5) to 10(-4) for traffic-related nano and ultrafine particle-bound PAHs, indicating a potential lung cancer risk. The particle size-specific PAF-based excess annual lung cancer incidence rate due to PAHs exposure was estimated to be less than 1 per 100,000 population, indicating a mild risk factor for lung cancer. We concluded that probabilistic risk assessment linked PAF for limiting cumulative PAHs emissions to reduce lung cancer risk plays a prominent role in future government risk assessment program. Copyright © 2011 Elsevier B.V. All rights reserved.

  6. Hyperhidrosis (Excessive Sweating)

    Science.gov (United States)

    ... who have this type are otherwise healthy. In medical terminology, the word “primary” means that the cause is not another medical condition. Secondary hyperhidrosis In medical terminology, “secondary” means that the excessive sweating (hyperhidrosis) has ...

  7. Rhizosphere effects of PAH-contaminated soil phytoremediation using a special plant named Fire Phoenix.

    Science.gov (United States)

    Liu, Rui; Xiao, Nan; Wei, Shuhe; Zhao, Lixing; An, Jing

    2014-03-01

    The rhizosphere effect of a special phytoremediating species known as Fire Phoenix on the degradation of polycyclic aromatic hydrocarbons (PAHs) was investigated, including changes of the enzymatic activity and microbial communities in rhizosphere soil. The study showed that the degradation rate of Σ8PAHs by Fire Phoenix was up to 99.40% after a 150-day culture. The activity of dehydrogenase (DHO), peroxidase (POD) and catalase (CAT) increased greatly, especially after a 60-day culture, followed by a gradual reduction with an increase in the planting time. The activity of these enzymes was strongly correlated to the higher degradation performance of Fire Phoenix growing in PAH-contaminated soils, although it was also affected by the basic characteristics of the plant species itself, such as the excessive, fibrous root systems, strong disease resistance, drought resistance, heat resistance, and resistance to barren soil. The activity of polyphenoloxidase (PPO) decreased during the whole growing period in this study, and the degradation rate of Σ8PAHs in the rhizosphere soil after having planted Fire Phoenix plants had a significant (R(2)=0.947) negative correlation with the change in the activity of PPO. Using an analysis of the microbial communities, the results indicated that the structure of microorganisms in the rhizosphere soil could be changed by planting Fire Phoenix plants, namely, there was an increase in microbial diversity compared with the unplanted soil. In addition, the primary advantage of Fire Phoenix was to promote the growth of flora genus Gordonia sp. as the major bacteria that can effectively degrade PAHs. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

  8. Distributions and Concentrations of PAHs in Hong Kong Soils

    International Nuclear Information System (INIS)

    Zhang, H.B.; Luo, Y.M.; Wong, M.H.; Zhao, Q.G.; Zhang, G.L.

    2006-01-01

    Surface soil (0-10 cm) samples from 53 sampling sites including rural and urban areas of Hong Kong were collected and analyzed for 16 EPA priority polycyclic aromatic hydrocarbons (PAHs). Total PAH concentrations were in the range of 7.0-410 μg kg -1 (dry wt), with higher concentrations in urban soils than that in rural soils. The three predominant PAHs were Fluoranthene, Naphthalene and Pyrene in rural soils, while Fluoranthene, Naphthalene and Benzo(b + k)fluoranthene dominated the PAHs of urban soils. The values of PAHs isomer indicated that biomass burning might be the major origin of PAHs in rural soils, but vehicular emission around the heavy traffic roads might contribute to the soil PAHs in urban areas. A cluster analysis was performed and grouped the detectable PAHs under 4 clusters, which could be indicative of the PAHs with different origins and PAHs affected by soil organic carbon contents respectively. - Baseline information is provided on levels, distributions and possible sources of PAHs in Hong Kong soils

  9. PAH-Mineral Interactions. A Laboratory Approach to Astrophysical Catalysis

    Science.gov (United States)

    Adolfo Cruz Diaz, Gustavo; Mattioda, Andrew

    2017-06-01

    Polycyclic Aromatic Hydrocarbon (PAH) molecules carry the infrared emission features which dominate the spectra of most galactic and extragalactic sources. Our study investigates the chemical evolution, chemical properties, physical properties, thermal stability, and photostability of samples produced from the UV-irradiation of simulated mineral dust grains coated with aromatics and astrobiologically relevant ices, using infrared spectroscopy. We investigate the chemical evolution of aromatic organics via anhydrous (no H2O ice) and hydrous (H2O ice) mechanisms. The anhydrous mechanism involves UV-induced catalytic reactions between organics and dense-cloud mineral grains, whereas the hydrous mechanism incorporates H2O-rich ice mixtures with the minerals and organics. These investigations identify the chemical and physical interactions occurring between the organic species, the dust grains and water-rich ices.These laboratory simulations also generate observable IR spectroscopic parameters for future astronomical observations with infrared telescopes such as SOFIA and JWST as well as provide empirical parameters for input into astronomical models of the early stages of planetary formation. These studies give us a deeper understanding of the potential catalytic pathways mineral surfaces provide and a deeper understanding of the role of ice-organic compositions in the chemical reaction pathways and how these processes fit into the formation of new planetary systems.In order to achieve these goals we use the Harrick ‘Praying Mantis’ Diffuse Reflectance Accessory (DRIFTS), which allows FTIR measurements of dust samples under ambient conditions by measuring the light scattered by the dust sample. We have also incorporated a low -temperature reaction chamber permitting the DRIFTS measurements at low temperatures and high-vacuum. This set-up permits the analysis of the solid particles surfaces revealing the chemical species adsorbed as well as their chemical evolution

  10. Superconductors with excess quasiparticles

    International Nuclear Information System (INIS)

    Elesin, V.F.; Kopaev, Y.V.

    1981-01-01

    This review presents a systematic kinetic theory of nonequilibrium phenomena in superconductors with excess quasiparticles created by electromagnetic or tunnel injection. The energy distributions of excess quasiparticles and of nonequilibrium phonons, dependence of the order parameter on the power and frequency (or intensity) of the electromagnetic field, magnetic properties of nonequilibrium superconductors, I-V curves of superconductor-insulator-superconductor junctions, and other properties are described in detail. The stability of superconducting states far from thermodynamic equilibrium is investigated and it is shown that characteristic instabilities leading to the formation of nonuniform states of a new type or phase transitions of the first kind are inherent to superconductors with excess quasiparticles. The results are compared with experimental data

  11. Excess wind power

    DEFF Research Database (Denmark)

    Østergaard, Poul Alberg

    2005-01-01

    Expansion of wind power is an important element in Danish climate change abatement policy. Starting from a high penetration of approx 20% however, momentary excess production will become an important issue in the future. Through energy systems analyses using the EnergyPLAN model and economic...... analyses it is analysed how excess productions are better utilised; through conversion into hydrogen of through expansion of export connections thereby enabling sales. The results demonstrate that particularly hydrogen production is unviable under current costs but transmission expansion could...

  12. Evaluation of PAH and PCB in soil

    International Nuclear Information System (INIS)

    Hein, D.; Delschen, T.

    1994-01-01

    The soil data obtained should be regarded as provisional, as there is still insufficient knowledge on the influence of accompanying substances such as organic solvents on the transfer behaviour and mobility of the soil pollutants under consideration. Moreover, the significance of metabolic processes in soils and plants is largely still unknown. There are no generally accepted standards for BCB and PAH analysis in soil and plants. The diversity in methods applied has led to widely disparate results. The data situation for PAH is so heterogeneous as to allow test results to be derived solely for benzo[a]pyrene. It will be a task for the future to clarify the extent to which other substances must be taken into account here, e.g., with respect to toxicity and availability. (orig.) [de

  13. Polycyclic aromatic hydrocarbons (PAHs) in yogurt samples.

    Science.gov (United States)

    Battisti, Chiara; Girelli, Anna Maria; Tarola, Anna Maria

    2015-01-01

    The concentrations and distributions of major polycyclic aromatic hydrocarbons (PAHs) were determined in 20 kinds of yogurt specimens collected from Italian supermarkets using reversed phase high-performance liquid chromatography equipped with fluorescence detection. The method was validated by determination of recovery percentages, precision (repeatability) and sensitivity (limits of detection) with yogurt samples fortified at 0.25, 0.5 and 1 µg/kg concentration levels. The recovery of 13 PAHs, with the exception of naphthalene and acenaphthene, ranged from 61% to 130% and from 60% to 97% at all the levels for yogurts with low (0.1%) and high (3.9%) fat content, respectively. The method is repeatable with relative standard deviation values yogurts with low and high fats were compared.

  14. Migration of polycyclic aromatic hydrocarbons (PAHs) in urban treatment sludge to the air during PAH removal applications.

    Science.gov (United States)

    Karaca, Gizem; Cindoruk, S Siddik; Tasdemir, Yücel

    2014-05-01

    In the present study, the amounts of polycylic aromatic hydrocarbons (PAHs) penetrating into air during PAH removal applications from the urban treatment sludge were investigated. The effects of the temperature, photocatalyst type, and dose on the PAH removal efficiencies and PAH evaporation were explained. The sludge samples were taken from an urban wastewater treatment plant located in the city of Bursa, with 585,000 equivalent population. The ultraviolet C (UV-C) light of 254 nm wavelength was used within the UV applications performed on a specially designed setup. Internal air of the setup was vacuumed through polyurethane foam (PUF) columns in order to collect the evaporated PAHs from the sludge during the PAH removal applications. All experiments were performed with three repetitions. The PAH concentrations were measured by gas chromatography-mass spectrometry (GC-MS). It was observed that the amounts of PAHs penetrating into the air were increased with increase of temperature, and more than 80% of PAHs migrated to the air consisted of 3-ring compounds during the UV and UV-diethylamine (DEA) experiments at 38 and 53 degrees C. It was determined that 40% decrease was ensured in sigma12 (total of 12) PAH amounts with UV application and 13% of PAHs in sludge penetrated into the air. In the UV-TiO2 applications, a maximum 80% of sigma12 PAH removal was obtained by adding 0.5% TiO2 of dry weight of sludge. The quantity of PAH penetrating into air did not exceed 15%. UV-TiO2 applications ensured high levels of PAH removal in the sludge and also reduced the quantity of PAH penetrating into the air. Within the scope of the samples added with DEA, there was no increase in PAH removal efficiencies and the penetration of PAHs into air was not decreased. In light of these data, it was concluded that UV-TiO2 application is the most suitable PAH removal alternative that restricts the convection of PAH pollution.

  15. PAH exposure levels in mudpuppy (amphibian)

    Energy Technology Data Exchange (ETDEWEB)

    Trudeau, F; Maisonneuve, F [Environment Canada, Canadian Wildlife Service, Hull, PQ (Canada); Gendron, A D [Quebec Univ., Montreal, PQ (Canada); Bishop, C A [Environment Canada, Canada Centre for Inland Waters, Burlington, ON (Canada)

    1999-12-31

    The presence of PAHs in the environment is of great concern because of the mutagenic, teratogenic and carcinogenic properties of the metabolites produced in exposed organisms. In recent years, exposure of fish to PAHs was demonstrated by the detection of pyrene-type metabolites in bile, using synchronous fluorescence spectrometry (SFS), which offers a rapid screening tool to estimate recent exposure to PAHs. In this experiment, the SFS technique was applied to mudpuppy (Necturus maculosus), a benthic carnivorous salamander found in the lakes and rivers of northeastern America, susceptible to the chronic effects of contaminants accumulated through its diet and through its contact with the contaminated sediment. Samples were taken from a variety of locations (Akwesasne River, Batiscan River, in the St.-Lawrence River System, Des Prairies River and Quesnel Bay in the Ottawa River System, Wolfe Island, Long Point and the Detroit River in the Great Lakes Basin). Results of the examination showed that mud puppies collected from the Detroit River had, by far, the highest concentrations of biliary 1-hydroxy pyrene (798 ng/ml), compared to 84 ng/ml, or less, in other animals in the sample.

  16. PAH partitioning in a toxicity exposure chamber

    International Nuclear Information System (INIS)

    Sterling, M.C. Jr.; Autenrieth, R.L.; Bonner, J.S.; Page, C.A.; Fuller, C.B.; Ernest, A.N.S.

    2003-01-01

    The hypothesis that observed petroleum aromatic hydrocarbon (PAH) concentrations in an aqueous system are equal to the sum of the organic phase and the soluble phase molar concentrations was examined. Raoult's law was used to estimate the soluble phase molar concentrations. The organic phase concentrations were proportional to the PAH mole fraction in the oil. The experiment involved initially loading a batch laboratory mixing vessel with a scalable mixing energy at various oil layer thicknesses corresponding to oil surface loadings. The vessel was then agitated at a constant mean shear rate. Periodical total petroleum hydrocarbon (TPH) samples were taken in order to estimate the entrainment rate as a function of initial oil layer thickness. In-situ measurements of TPH concentrations were performed with the use of a laser scattering instrument while ex-situ measurements were effected using gravimetric analysis. Additional samples were analyzed for PAH concentration at a steady state TPH concentration using gas chromatograph/mass spectrometer (GC/MS) analysis. The results obtained were in agreement with a first order kinetic model (TPH concentrations increased over time). It was noted that in general, the first order rate constant and steady state concentration increased with increased oil loading and increased mean shear rates. There was good correlation between the measurements and the concentrations predicted using the hypothesized model. 8 refs., 3 tabs., 2 figs

  17. Disposition of excess material

    International Nuclear Information System (INIS)

    Hall, J.C.

    1978-01-01

    This paper reviews briefly the means available to an enrichment customer to dispose of excess material scheduled for delivery under a fixed-commitment contract, other than through termination of the related separative work. The methods are as follows: (1) sales; (2) use in facilities covered by other DOE contracts; and (3) assignment

  18. HIV Excess Cancers JNCI

    Science.gov (United States)

    In 2010, an estimated 7,760 new cancers were diagnosed among the nearly 900,000 Americans known to be living with HIV infection. According to the first comprehensive study in the United States, approximately half of these cancers were in excess of what wo

  19. The hydrogen coverage of interstellar PAHs [Polycyclic Aromatic Hydrocarbons

    International Nuclear Information System (INIS)

    Tielens, A.G.G.M.; Allamandola, L.J.; Barker, J.R.; Cohen, M.

    1986-02-01

    The rate at which the CH bond in interstellar Polycyclic Aromatic Hydrocarbons (PAHs) rupture due to the absorption of a uv photon has been calculated. The results show that small PAHs (less than or equal to 25 carbon atoms) are expected to be partially dehydrogenated in regions with intense uv fields, while large PAHs (greater than or equal to 25 atoms) are expected to be completely hydrogenated in those regions. Because estimate of the carbon content of interstellar PAHs lie in the range of 20 to 25 carbon atoms, dehydrogenation is probably not very important. Because of the absence of other emission features besides the 11.3 micrometer feature in ground-based 8 to 13 micrometer spectra, it has been suggested that interstellar PAHs are partially dehydrogenated. However, IRAS 8 to 22 micrometer spectra of most sources that show strong 7.7 and 11.2 micrometer emission features also show a plateau of emission extending from about 11.3 to 14 micrometer. Like the 11.3 micrometer feature, this new feature is attributed to the CH out of plane bending mode in PAHs. This new feature shows that interstellar PAHs are not as dehydrogenated as estimated from ground-based 8 to 13 micrometer spectra. It also constrains the molecular structure of interstellar PAHs. In particular, it seems that very condensed PAHs, such as coronene and circumcoronene, dominate the interstellar PAH mixture as expected from stability arguments

  20. Growth of nano hexagon-like flake arrays cerium carbonate created with PAH as the substrate

    Energy Technology Data Exchange (ETDEWEB)

    Li, M., E-mail: limei@imust.cn [School of Materials Science and Engineering, Beijing University of Chemical Engineering, Department of Materials, Beijing 100029 (China); School of Materials and Metallurgy, Inner Mongolia University of Science and Technology, Department of Inorganic and Metalloid Materials, Key Laboratory of New Technologies of Modern Metallurgy and Application of Rare Materials, Baotou 014010 (China); Hu, Y.H., E-mail: bthyh@163.com [School of Materials Science and Engineering, Beijing University of Chemical Engineering, Department of Materials, Beijing 100029 (China); School of Materials and Metallurgy, Inner Mongolia University of Science and Technology, Department of Inorganic and Metalloid Materials, Key Laboratory of New Technologies of Modern Metallurgy and Application of Rare Materials, Baotou 014010 (China); Liu, Z.G.; Wang, X.F.; Wang, M.T. [School of Materials and Metallurgy, Inner Mongolia University of Science and Technology, Department of Inorganic and Metalloid Materials, Key Laboratory of New Technologies of Modern Metallurgy and Application of Rare Materials, Baotou 014010 (China)

    2015-01-15

    Petals-like Ce{sub 2}(CO{sub 3}){sub 3} on Ce{sub 2}(CO{sub 3}){sub 3} nano hexagon-like flake arrays have been precipitatingly fabricated using PAH substrates. By changing the way of feeding, PAH concentration and aging time, petals-like Ce{sub 2}(CO{sub 3}){sub 3} was created best when adding PAH into the Ce(NO{sub 3}){sub 3} solution, joined (NH{sub 4}){sub 2}CO{sub 3} solution along with mixing, PAH concentration is 0.9 g/L, aging time is 4 h. A growth mechanism was proposed to account for the growth of the petals-like Ce{sub 2}(CO{sub 3}){sub 3} with PAH as the substrate. Poly allylamine hydrochloride (PAH) is as template agent which forms π-allyl complex with Ce{sup 3+} and controls the morphology of Ce{sub 2}(CO{sub 3}){sub 3} particle. PAH and Ce{sup 3+} form π-allyl complex, and then induce the formation of Ce{sub 2}(CO{sub 3}){sub 3} crystal nucleus. And infrared spectrum analysis verified. XRD show that after adding PAH which is adsorbed on the crystal plane, the growth of Ce{sub 2}(CO{sub 3}){sub 3} crystal is inhibited on (2 4 2), the growth is promoted on (2 0 2) which is differentiated into the new (1 5 1), (2 2 2) is unchanged, Ce{sub 2}(CO{sub 3}){sub 3} crystal is accumulated petals shape by hexagon-like flake. UV absorption spectra show that CeO{sub 2} as prepared precursor Ce{sub 2}(CO{sub 3}){sub 3} after calcinations in air at high temperatures, the petal-like CeO{sub 2} has strong UV absorption and reflection effects, and absorption interval changed significantly by the move to UVA from UVB. - Graphical abstract: Each Ce-atom connects three Cl-atoms and three allyls in three dimensional spaces. To take the plane as a reference plane which is arrayed with three Ce-atom as equilateral triangle. The triangular each vertex is Ce-atom, the triangular center place is Cl-atom, the equilateral triangle which is mutually perpendicular with Ce-triangle surface and the inclined angle is 60° is made up with three Cl-atoms. - Highlights: • Petals

  1. Mitigation of PAH and nitro-PAH emissions from nonroad diesel engines.

    Science.gov (United States)

    Liu, Z Gerald; Wall, John C; Ottinger, Nathan A; McGuffin, Dana

    2015-03-17

    More stringent emission requirements for nonroad diesel engines introduced with U.S. Tier 4 Final and Euro Stage IV and V regulations have spurred the development of exhaust aftertreatment technologies. In this study, several aftertreatment configurations consisting of diesel oxidation catalysts (DOC), diesel particulate filters (DPF), Cu zeolite-, and vanadium-based selective catalytic reduction (SCR) catalysts, and ammonia oxidation (AMOX) catalysts are evaluated using both Nonroad Transient (NRTC) and Steady (8-mode NRSC) Cycles in order to understand both component and system-level effects of diesel aftertreatment on emissions of polycyclic aromatic hydrocarbons (PAH) and their nitrated derivatives (nitro-PAH). Emissions are reported for four configurations including engine-out, DOC+CuZ-SCR+AMOX, V-SCR+AMOX, and DOC+DPF+CuZ-SCR+AMOX. Mechanisms responsible for the reduction, and, in some cases, the formation of PAH and nitro-PAH compounds are discussed in detail, and suggestions are provided to minimize the formation of nitro-PAH compounds through aftertreatment design optimizations. Potency equivalency factors (PEFs) developed by the California Environmental Protection Agency are then applied to determine the impact of aftertreatment on PAH-derived exhaust toxicity. Finally, a comprehensive set of exhaust emissions including criteria pollutants, NO2, total hydrocarbons (THC), n-alkanes, branched alkanes, saturated cycloalkanes, aromatics, aldehydes, hopanes and steranes, and metals is provided, and the overall efficacy of the aftertreatment configurations is described. This detailed summary of emissions from a current nonroad diesel engine equipped with advanced aftertreatment can be used to more accurately model the impact of anthropogenic emissions on the atmosphere.

  2. THE INFRARED SPECTROSCOPY OF COMPACT POLYCYCLIC AROMATIC HYDROCARBONS CONTAINING UP TO 384 CARBONS

    International Nuclear Information System (INIS)

    Ricca, Alessandra; Bauschlicher, Charles W. Jr.; Boersma, Christiaan; Allamandola, Louis J.; Tielens, Alexander G. G. M.

    2012-01-01

    The mid- and the far-infrared spectra of polycyclic aromatic hydrocarbons (PAHs) have been computed using density functional theory. This study has focused on PAHs in the highly symmetric, compact, coronene family with sizes up to 384 carbons. We have identified trends in the peak position and intrinsic strength of the vibrational modes of these species and compared these to trends previously reported for less symmetric and smaller PAHs. The computed spectral modes have been used to calculate the IR emission spectrum of PAHs pumped by UV photons. The results have been compared to observed interstellar spectra to elucidate the characteristics of the interstellar PAH family. The calculations show that highly symmetric PAHs are very stable and, hence, might be favored under the harsh conditions of interstellar space. Our calculated vibrational properties confirm and extend previous studies for small PAHs to the large compact PAHs studied here, specifically in terms of the dependence of the spectral characteristics on ionization and on H-adjacency. The calculations show that for PAHs larger than 150 carbons, the 6.3 μm feature becomes very broad and shifts to longer wavelengths, the 8.6 μm band becomes stronger than the '7.7' μm band, and the 11.0/12.7 band strength ratio gets too large compared with observations. Thus, PAHs with 150 carbons or more are unlikely to be the dominant species in interstellar space. The simplicity of the observed spectra in the 15-20 μm range points toward a preponderance of compact PAHs in the interstellar PAH family.

  3. THE INFRARED SPECTROSCOPY OF COMPACT POLYCYCLIC AROMATIC HYDROCARBONS CONTAINING UP TO 384 CARBONS

    Energy Technology Data Exchange (ETDEWEB)

    Ricca, Alessandra [Carl Sagan Center, SETI Institute, 189 Bernardo Avenue, Mountain View, CA 94043 (United States); Bauschlicher, Charles W. Jr. [Entry Systems and Technology Division, Mail Stop 230-3, NASA Ames Research Center, Moffett Field, CA 94035 (United States); Boersma, Christiaan; Allamandola, Louis J. [Space Science Division, Mail Stop 245-6, NASA Ames Research Center, Moffett Field, CA 94035 (United States); Tielens, Alexander G. G. M., E-mail: Alessandra.Ricca-1@nasa.gov, E-mail: Charles.W.Bauschlicher@nasa.gov, E-mail: Louis.J.Allamandola@nasa.gov, E-mail: Christiaan.Boersma@nasa.gov, E-mail: tielens@strw.leidenuniv.nl [Leiden Observatory, Leiden University, P.O. Box 9513, NL-2300 RA (Netherlands)

    2012-07-20

    The mid- and the far-infrared spectra of polycyclic aromatic hydrocarbons (PAHs) have been computed using density functional theory. This study has focused on PAHs in the highly symmetric, compact, coronene family with sizes up to 384 carbons. We have identified trends in the peak position and intrinsic strength of the vibrational modes of these species and compared these to trends previously reported for less symmetric and smaller PAHs. The computed spectral modes have been used to calculate the IR emission spectrum of PAHs pumped by UV photons. The results have been compared to observed interstellar spectra to elucidate the characteristics of the interstellar PAH family. The calculations show that highly symmetric PAHs are very stable and, hence, might be favored under the harsh conditions of interstellar space. Our calculated vibrational properties confirm and extend previous studies for small PAHs to the large compact PAHs studied here, specifically in terms of the dependence of the spectral characteristics on ionization and on H-adjacency. The calculations show that for PAHs larger than 150 carbons, the 6.3 {mu}m feature becomes very broad and shifts to longer wavelengths, the 8.6 {mu}m band becomes stronger than the '7.7' {mu}m band, and the 11.0/12.7 band strength ratio gets too large compared with observations. Thus, PAHs with 150 carbons or more are unlikely to be the dominant species in interstellar space. The simplicity of the observed spectra in the 15-20 {mu}m range points toward a preponderance of compact PAHs in the interstellar PAH family.

  4. PAH biomarkers in common eelpout (Zoarces viviparus) from Danish waters

    DEFF Research Database (Denmark)

    Tairova, Zhanna; Strand, Jakob; Chevalier, Julie

    2012-01-01

    Eelpouts (Zoarces viviparus) sampled at surveillance stations during the fall of 2007 and spring 2008 in different Danish coastal areas, were studied for biomarkers of polycyclic aromatic hydrocarbons (PAHs) exposure and effects. Two analytical techniques, synchronous fluorescence spectrometry (SFS......) and high-performance liquid chromatography with fluorescence detection (HPLC/F), were applied for detecting PAH metabolites in bile and urine. CYP1A activity, in this study regarded as potential biomarker of effect, was measured as 7-ethoxyresorufin-O-deethylase (EROD) activity in liver of eelpouts from...... different stations. Biliary PAH metabolite measurements were used for monitoring the environmental PAH load at the surveillance stations. There was found significant difference in biliary PAH metabolite content between sexes with male fish containing higher concentrations of PAH metabolites than females...

  5. Laboratory Formation of Fullerenes from PAHs: Top-down Interstellar Chemistry

    Science.gov (United States)

    Zhen, Junfeng; Castellanos, Pablo; Paardekooper, Daniel M.; Linnartz, Harold; Tielens, Alexander G. G. M.

    2014-12-01

    Interstellar molecules are thought to build up in the shielded environment of molecular clouds or in the envelope of evolved stars. This follows many sequential reaction steps of atoms and simple molecules in the gas phase and/or on (icy) grain surfaces. However, these chemical routes are highly inefficient for larger species in the tenuous environment of space as many steps are involved and, indeed, models fail to explain the observed high abundances. This is definitely the case for the C60 fullerene, recently identified as one of the most complex molecules in the interstellar medium. Observations have shown that, in some photodissociation regions, its abundance increases close to strong UV-sources. In this Letter we report laboratory findings in which C60 formation can be explained by characterizing the photochemical evolution of large polycyclic aromatic hydrocarbons (PAHs). Sequential H losses lead to fully dehydrogenated PAHs and subsequent losses of C2 units convert graphene into cages. Our results present for the first time experimental evidence that PAHs in excess of 60 C-atoms efficiently photo-isomerize to buckminsterfullerene, C60. These laboratory studies also attest to the importance of top-down synthesis routes for chemical complexity in space.

  6. LABORATORY FORMATION OF FULLERENES FROM PAHS: TOP-DOWN INTERSTELLAR CHEMISTRY

    International Nuclear Information System (INIS)

    Zhen, Junfeng; Castellanos, Pablo; Tielens, Alexander G. G. M.; Paardekooper, Daniel M.; Linnartz, Harold

    2014-01-01

    Interstellar molecules are thought to build up in the shielded environment of molecular clouds or in the envelope of evolved stars. This follows many sequential reaction steps of atoms and simple molecules in the gas phase and/or on (icy) grain surfaces. However, these chemical routes are highly inefficient for larger species in the tenuous environment of space as many steps are involved and, indeed, models fail to explain the observed high abundances. This is definitely the case for the C 60 fullerene, recently identified as one of the most complex molecules in the interstellar medium. Observations have shown that, in some photodissociation regions, its abundance increases close to strong UV-sources. In this Letter we report laboratory findings in which C 60 formation can be explained by characterizing the photochemical evolution of large polycyclic aromatic hydrocarbons (PAHs). Sequential H losses lead to fully dehydrogenated PAHs and subsequent losses of C 2 units convert graphene into cages. Our results present for the first time experimental evidence that PAHs in excess of 60 C-atoms efficiently photo-isomerize to buckminsterfullerene, C 60 . These laboratory studies also attest to the importance of top-down synthesis routes for chemical complexity in space

  7. Infrared thermal annealing device

    International Nuclear Information System (INIS)

    Gladys, M.J.; Clarke, I.; O'Connor, D.J.

    2003-01-01

    A device for annealing samples within an ultrahigh vacuum (UHV) scanning tunneling microscopy system was designed, constructed, and tested. The device is based on illuminating the sample with infrared radiation from outside the UHV chamber with a tungsten projector bulb. The apparatus uses an elliptical mirror to focus the beam through a sapphire viewport for low absorption. Experiments were conducted on clean Pd(100) and annealing temperatures in excess of 1000 K were easily reached

  8. Excessive crying in infants

    Directory of Open Access Journals (Sweden)

    Ricardo Halpern

    2016-05-01

    Conclusion: Excessive crying in the early months is a prevalent symptom; the pediatrician's attention is necessary to understand and adequately manage the problem and offer support to exhausted parents. The prescription of drugs of questionable action and with potential side effects is not a recommended treatment, except in extreme situations. The effectiveness of dietary treatments and use of probiotics still require confirmation. There is incomplete evidence regarding alternative treatments such as manipulation techniques, acupuncture, and use of the herbal supplements and behavioral interventions.

  9. Barns kjemiske lekemiljø: Nivå og kilder til PAH i barnehagejord i Trondheim

    OpenAIRE

    Frøland, Stine Lindset

    2008-01-01

    Innholdet av 16 PAH-forbindelser og sumPAH(16) ble bestemt i 107 prøver av overflatejord fordelt på 10 barnehager i Trondheim. Sammenlignet med tidligere undersøkelser av PAH i Trondheim viser barnehagene det laveste innholdet av PAH. I barnehagene antydes det at vedfyring og veitrafikk er viktige kilder til den diffuse forurensningen av PAH.

  10. ACTIVATION PARAMETERS AND EXCESS THERMODYANAMIC ...

    African Journals Online (AJOL)

    Applying these data, viscosity-B-coefficients, activation parameters (Δμ10≠) and (Δμ20≠) and excess thermodynamic functions, viz., excess molar volume (VE), excess viscosity, ηE and excess molar free energy of activation of flow, (GE) were calculated. The value of interaction parameter, d, of Grunberg and Nissan ...

  11. Impacts of a large boreal wildfire on ground level atmospheric concentrations of PAHs, VOCs and ozone

    Science.gov (United States)

    Wentworth, Gregory R.; Aklilu, Yayne-abeba; Landis, Matthew S.; Hsu, Yu-Mei

    2018-04-01

    During May 2016 a very large boreal wildfire burned throughout the Athabasca Oil Sands Region (AOSR) in central Canada, and in close proximity to an extensive air quality monitoring network. This study examines speciated 24-h integrated polycyclic aromatic hydrocarbon (PAH) and volatile organic compound (VOC) measurements collected every sixth day at four and seven sites, respectively, from May to August 2016. The sum of PAHsPAH) was on average 17 times higher in fire-influenced samples (852 ng m-3, n = 8), relative to non-fire influenced samples (50 ng m-3, n = 64). Diagnostic PAH ratios in fire-influenced samples were indicative of a biomass burning source, whereas ratios in June to August samples showed additional influence from petrogenic and fossil fuel combustion. The average increase in the sum of VOCs (ΣVOC) was minor by comparison: 63 ppbv for fire-influenced samples (n = 16) versus 46 ppbv for non-fire samples (n = 90). The samples collected on August 16th and 22nd had large ΣVOC concentrations at all sites (average of 123 ppbv) that were unrelated to wildfire emissions, and composed primarily of acetaldehyde and methanol suggesting a photochemically aged air mass. Normalized excess enhancement ratios (ERs) were calculated for 20 VOCs and 23 PAHs for three fire influenced samples, and the former were generally consistent with previous observations. To our knowledge, this is the first study to report ER measurements for a number of VOCs and PAHs in fresh North American boreal wildfire plumes. During May the aged wildfire plume intercepted the cities of Edmonton (∼380 km south) or Lethbridge (∼790 km south) on four separate occasions. No enhancement in ground-level ozone (O3) was observed in these aged plumes despite an assumed increase in O3 precursors. In the AOSR, the only daily-averaged VOCs which approached or exceeded the hourly Alberta Ambient Air Quality Objectives (AAAQOs) were benzene (during the fire) and acetaldehyde (on August 16th

  12. Grafted cellulose for PAHs removal present in industrial discharge waters

    Science.gov (United States)

    Euvrard, Elise; Druart, Coline; Poupeney, Amandine; Crini, Nadia; Vismara, Elena; Lanza, Tommaso; Torri, Giangiacomo; Gavoille, Sophie; Crini, Gregorio

    2014-05-01

    Keywords: cellulose; biosorbent; PAHs; polycontaminated wastewaters; trace levels. Polycyclic aromatic hydrocarbons (PAHs), chemicals essentially formed during incomplete combustion of organic materials from anthropogenic activities, were present in all compartments of the ecosystem, air, water and soil. Notably, a part of PAHs found in aquatic system was introduced through industrial discharge waters. Since the Water Framework Directive has classified certain PAHs as priority hazardous substances, industrials are called to take account this kind of organic pollutants in their global environmental concern. Conventional materials such as activated carbons definitively proved their worth as finishing treatment systems but remained costly. In this study, we proposed to use cellulose grafted with glycidyl methacrylate [1] for the removal of PAHs present in discharge waters of surface treatment industries. Firstly, to develop the device, we worked with synthetic solutions containing 16 PAHs at 500 ng/L. Two types of grafted cellulose were tested over a closed-loop column with a concentration of 4g cellulose/L: cellulose C2 with a hydroxide group and cellulose C4 with an amine group. No PAH was retained by the raw cellulose whereas abatement percentages of PAHs were similar between C2 and C4 (94% and 98%, respectively, for the sum of the 16 PAHs) with an experiment duration of 400 min (corresponding to about 20 cycles through grafted cellulose). Secondly, to determine the shorter time to abate the amount maximum of PAHs through the system, a kinetic was realized from 20 min (one cycle) to 400 min with C4. The steady state (corresponding to about 95% of abatement of the total PAHs) was reached at 160 min. Finally, the system was then tested with real industrial discharge waters containing both mineral and organic compounds. The results indicated that the abatement percentage of PAHs was similar between C2 and C4, corroborating the tests with synthetic solution. In return

  13. PAH in Some Brands of Tea and Coffee

    DEFF Research Database (Denmark)

    Duedahl-Olesen, Lene; Navaratnam, Marin Arosha; Jewula, J.

    2015-01-01

    The presence of 25 polycyclic aromatic hydrocarbons (PAHs) in tea and coffee were investigated with focus on four PAHs (PAH4), classified by the European Food Safety Authority (EFSA) as suitable indicators; benz[a]anthracene (BaA), chrysene (CHR), benzo[b]fluoranthene (BbF) and benzo[a]pyrene (Ba......P). PAH4 from samples of 18 brands of tea leaves and 13 brands of coffee were extracted by pressurized liquid extraction (PLE) followed by highly automated clean up steps for gel permeation chromatography (SX-3) and solid phase extraction (500mg silica). GC-MS were applied for detection of PAH4. The limit...... of detection (LOD) ranged from 0.1–0.3 μg/kg with recoveries from 94–106% for PAH4. Concentrations of PAH4 followed the pattern of the total sum of 25 PAHs with higher concentrations with a maximum of 115 μg/kg in tea leaves compared to 5.1 μg/kg in coffee. The highest PAH4 levels were found in black tea...

  14. PAH related effects on fish in sedimentation ponds for road runoff and potential transfer of PAHs from sediment to biota

    DEFF Research Database (Denmark)

    Grung, Merete; Petersen, Karina; Fjeld, Eirik

    2016-01-01

    of the sedimentation ponds were high (1900-4200ngg(-1)), and even higher levels were observed in plants. Principal component analysis of selected ion chromatograms of PAHs showed a clear separation of plants vs. sediments. The plants preferentially accumulated the high molecular PAHs, both from sedimentation ponds......) the transfer of PAHs from road runoff material to aquatic organisms was substantial. Minnow from a sedimentation pond (Skullerud) near Oslo (Norway) had higher levels of CYP1A enzyme and DNA stand breaks than minnow from the nearby river, but high concentrations of PAH-metabolites in bile revealed that both...... populations were highly exposed. Principal component analysis revealed that CYP1A and age of fish were correlated, while levels of PAH-metabolites were not correlated to CYP1A or DNA damage. Minnow from a lake un-affected by traffic had much lower levels of PAH-metabolites than the exposed fish, and also...

  15. Global time trends in PAH emissions from motor vehicles

    Science.gov (United States)

    Shen, Huizhong; Tao, Shu; Wang, Rong; Wang, Bin; Shen, Guofeng; Li, Wei; Su, Shenshen; Huang, Ye; Wang, Xilong; Liu, Wenxin; Li, Bengang; Sun, Kang

    2011-04-01

    Emission from motor vehicles is the most important source of polycyclic aromatic hydrocarbons (PAHs) in urban areas. Emission factors of individual PAHs for motor vehicles reported in the literature varied 4 to 5 orders of magnitude, leading to high uncertainty in emission inventory. In this study, key factors affecting emission factors of PAHs (EF PAH) for motor vehicles were evaluated quantitatively based on thousands of EF PAH measured in 16 countries for over 50 years. The result was used to develop a global emission inventory of PAHs from motor vehicles. It was found that country and vehicle model year are the most important factors affecting EF PAH, which can be quantified using a monovariate regression model with per capita gross domestic production (purchasing power parity) as a sole independent variable. On average, 29% of variation in log-transformed EF PAH could be explained by the model, which was equivalent to 90% reduction in overall uncertainty on arithmetic scale. The model was used to predict EF PAH and subsequently PAH emissions from motor vehicles for various countries in the world during a period from 1971 to 2030. It was estimated that the global emission reached its peak value of approximate 101 Gg in 1978 and decreased afterwards due to emission control in developed countries. The annual emission picked up again since 1990 owing to accelerated energy consumption in China and other developing countries. With more and more rigid control measures taken in the developing world, global emission of PAHs is currently passing its second peak. It was predicted that the emission would decrease from 77 Gg in 2010 to 42 Gg in 2030.

  16. Cloud deposition of PAHs at Mount Lushan in southern China.

    Science.gov (United States)

    Wang, Ruixia; Wang, Yan; Li, Hongli; Yang, Minmin; Sun, Lei; Wang, Tao; Wang, Wenxing

    2015-09-01

    Cloud water samples were collected from Mount Lushan, a high alpine area of southern China, and analyzed using GC-MS to investigate the concentration levels, seasonal variations, particle-dissolved phase partitioning, ecological risk of PAHs and its relationship to the atmosphere and rainwater. The average concentration of total (dissolved+particle) PAHs in cloud water was 819.90 ng/L, which ranged from 2.30 ng/L for DbA to 295.38 ng/L for PhA. PhA (33.11%) contributed the most individual PAHs, followed by Flu (28.24%). Distinct seasonal variations in the total PAHs measured in this research had a higher concentration during the spring and a lower concentration during the summer. When cloud events occurred, the concentration of the atmospheric PAHs of the two phases decreased. The contribution from the gaseous phase of total PAHs in the air to the dissolved phase in cloud water was up to 60.43%, but the particulate phase in the air only contributed 39.57% to the total scavenging. The contribution of total PAHs from the atmosphere to clouds is higher in the gaseous phase than in the particulate phase. A comparative study of the concentrations of cloud water and the closest rain water revealed that the PAH concentration in rainwater was 1.80 times less than that of cloud water and that the dominant individual compounds in cloud water and rainwater were PhA and Flu. A total of 81.27% of the PAHs in cloud samples and 72.21% of the PAHs in rain samples remained in the dissolved phase. Ecological risk assessment indicated that PAHs in cloud water in spring and summer caused a certain degree of ecosystem risk and the mean ecosystem risk in spring was higher than that in summer. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Major gaseous and PAH emissions from a fluidized-bed combustor firing rice husk with high combustion efficiency

    International Nuclear Information System (INIS)

    Janvijitsakul, Kasama; Kuprianov, Vladimir I.

    2008-01-01

    This experimental work investigated major gaseous (CO and NO x ) and PAH emissions from a 400 kW th fluidized-bed combustor with a cone-shaped bed (referred to as 'conical FBC') firing rice husk with high, over 99%, combustion efficiency. Experimental tests were carried out at the fuel feed rate of 80 kg/h for different values of excess air (EA). As revealed by the experimental results, EA had substantial effects on the axial CO and NO x concentration profiles and corresponding emissions from the combustor. The concentration (mg/kg-ash) and specific emission (μg/kW h) of twelve polycyclic aromatic hydrocarbons (PAHs), acenaphthylene, fluorene, phenanthrene, fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenz[a,h]anthracene and indeno[1,2,3-cd]pyrene, were quantified in this work for different size fractions of ash emitted from the conical FBC firing rice husk at EA = 20.9%. The total PAHs emission was found to be predominant for the coarsest ash particles, due to the effects of a highly developed internal surface in a particle volume. The highest emission was shown by acenaphthylene, 4.1 μg/kW h, when the total yield of PAHs via fly ash was about 10 μg/kW h. (author)

  18. Contribution of Fossil Fuels and Wood Combustion to Carcinogenic PAHs in the Ambient Atmosphere of a Tropical Megacity

    Science.gov (United States)

    Jyethi, D. S.; Khillare, P. S.; Sarkar, S.

    2015-12-01

    Weekly particulate matter sampling was carried out at a peri-urban site located in megacity Delhi, India for 1 year (2009-2010) and the annual mean PM10 level was found to be ˜9 times the World Health Organization limit. Seasonal variation of PAHs (range 37.2-74.0 ng m-3) was significant with winter values being 72% and 68% higher than summer and monsoon respectively. Principal component analysis coupled with multiple linear regression identified diesel, natural gas and lubricating oil combustion (49.5%), wood combustion (25.4%), gasoline (15.5%) and coal combustion (9.6%) sources for the observed PAHs. Heavy traffic on the national highway and arterial roads and domestic emissions from suburban households in the vicinity of the site appeared to have significantly affected its air quality. A substantial portion (˜55%) of the aerosol PAH load was comprised of carcinogenic species, which yielded a considerably high lifetime inhalation cancer risk estimate (8.7E-04). If considered as a conservative lower-bound estimate, this risk translates into ˜211 excess cancer cases for lifetime inhalation exposure to the observed PAH concentrations in Delhi.

  19. THE FAR-INFRARED SPECTROSCOPY OF VERY LARGE NEUTRAL POLYCYCLIC AROMATIC HYDROCARBONS

    International Nuclear Information System (INIS)

    Ricca, Alessandra; Bauschlicher, Charles W.; Mattioda, Andrew L.; Boersma, Christiaan; Allamandola, Louis J.

    2010-01-01

    Here we report the computed far-infrared (FIR) spectra of neutral polycyclic aromatic hydrocarbon (PAH) molecules containing at least 82 carbons up to 130 carbons and with shapes going from compact round and oval-type structures to rectangular and to trapezoidal. The effects of size and shape on the FIR band positions and intensities are discussed. Using FIR data from the NASA Ames PAH IR Spectroscopic Database Version 1.1, we generate synthetic spectra that support the suggestion that the 16.4, 17.4, and 17.8 μm bands arise from PAHs.

  20. [Comparison of polycyclic aromatic hydrocarbons (PAHS) contents in bakery products].

    Science.gov (United States)

    Ciemniak, Artur; Witczak, Agata

    2010-01-01

    Polycyclic aromatic hydrocarbons are a group of well-known chemical carcinogens with a wide distribution in the environment and formed by the incomplete combustion of organic substances. PAHs have attracted most attention because of their carcinogenic potential. PAHs have been found as contaminants in different food categories such as dairy products, smoked and barbecued meat, vegetables, fruits, oils, coffee, tea, and cereals. Processing of food at high temperatures increases the amount of PAHs in the food Diet is the major source of human exposure to PAHs. The major dietary source of PAH are oils and fats, cereals products and vegetables. The aims of this study were to determine the content levels of 23 PAHs in various sorts of bread. The analytical procedure was based Soxhlet extraction with n--hexane and cleaned up in aflorisil cartridge. Chromatographic separation was performed using gas chromatography (HP 6890) coupled to mass spectrometry (HP 5973). The total concentration of PAHs was low end varied between 2.61 microg/kg to 43.4 microg/kg. Furthermore, the results revealed differences in concentrations of PAHs between rind and bread-crumb.

  1. Rapid persulfate oxidation predicts PAH bioavailability in soils and sediments

    NARCIS (Netherlands)

    Cuypers, M.P.; Grotenhuis, J.T.C.; Joziasse, J.; Rulkens, W.H.

    2000-01-01

    Persulfate oxidation was validated as a method to predict polycyclic aromatic hydrocarbon (PAH) bioavailability in soils and sediments. It was demonstrated for 14 field contaminated soils and sediments that residual PAH concentrations after a short (3 h) persulfate oxidation correspond well to

  2. Effect of Smoking on Polycyclic Aromatic Hydrocarbons (PAHS ...

    African Journals Online (AJOL)

    ADOWIE PERE

    Manage. Vol. 22 (2) 293 - 297. February 2018. Full-text Available Online at ... aromatic hydrocarbons (PAHs) were studied in raw and smoked samples of catfish (Clarias ... inferred that the smoking process generally increased the mean total PAH levels in the fish .... with 5 g of anhydrous sodium sulphate in a laboratory.

  3. Polyaromatic hydrocarbons (PAHs) levels from two industrial zones ...

    African Journals Online (AJOL)

    Polyaromatic hydrocarbons (PAHs) levels from two industrial zones (Sihwa and Banwal) located in An-san city ... PROMOTING ACCESS TO AFRICAN RESEARCH ... method (HVAS-Sibata) was employed to collect airborne PAHs in both the particulate and gas phases. ... EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT

  4. Levels of PAHs in shrimps, Penaeus monodon from Jones Creek ...

    African Journals Online (AJOL)

    High concentrations were recorded during the rainy season and during the first quarter of the year. The investigated samples were classified as minimally contaminated when compared with FDA levels of PAHs in shrimp samples. Distribution patterns showed that PAHs with 3 and 4 rings dominated confirming the pyrogenic ...

  5. Urinary 1-hydroxypyrene, a PAH biomarker in foundry workers

    DEFF Research Database (Denmark)

    Omland, Øyvind; Sherson, David; Hansen, Åse Marie

    1996-01-01

    Exposure to PAH in foundry workers has been studied by urinary 1-hydroxypyrene (HPU) levels, quantitatively measured by reversed phase HPLC. Seventy male foundry workers and 68 matched controls were investigated. Polycyclic aromatic hydrocarbon (PAH) exposure was defined by 17 breathing zone hygi...

  6. PAH loss during bioremediation of manufactured gas plant site soils

    Energy Technology Data Exchange (ETDEWEB)

    Erickson, D C [and others

    1993-01-01

    Laboratory studies using soil samples from a former gas works site showed that PAH in the soil were present in a form resistant to biodegradation, whereas added naphthalene and phenanthrene were quickly degraded. The PAH already present were not extractable into water, and were not toxic to bacteria.

  7. Excessive crying in infants

    Directory of Open Access Journals (Sweden)

    Ricardo Halpern

    2016-05-01

    Full Text Available Objective: Review the literature on excessive crying in young infants, also known as infantile colic, and its effects on family dynamics, its pathophysiology, and new treatment interventions. Data source: The literature review was carried out in the Medline, PsycINFO, LILACS, SciELO, and Cochrane Library databases, using the terms “excessive crying,” and “infantile colic,” as well technical books and technical reports on child development, selecting the most relevant articles on the subject, with emphasis on recent literature published in the last five years. Summary of the findings: Excessive crying is a common symptom in the first 3 months of life and leads to approximately 20% of pediatric consultations. Different prevalence rates of excessive crying have been reported, ranging from 14% to approximately 30% in infants up to 3 months of age. There is evidence linking excessive crying early in life with adaptive problems in the preschool period, as well as with early weaning, maternal anxiety and depression, attention deficit hyperactivity disorder, and other behavioral problems. Several pathophysiological mechanisms can explain these symptoms, such as circadian rhythm alterations, central nervous system immaturity, and alterations in the intestinal microbiota. Several treatment alternatives have been described, including behavioral measures, manipulation techniques, use of medication, and acupuncture, with controversial results and effectiveness. Conclusion: Excessive crying in the early months is a prevalent symptom; the pediatrician's attention is necessary to understand and adequately manage the problem and offer support to exhausted parents. The prescription of drugs of questionable action and with potential side effects is not a recommended treatment, except in extreme situations. The effectiveness of dietary treatments and use of probiotics still require confirmation. There is incomplete evidence regarding alternative treatments

  8. Cloud deposition of PAHs at Mount Lushan in southern China

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ruixia [School of Environmental Science and Engineering, Shandong University, Jinan, 250100 (China); Wang, Yan, E-mail: wangyan405@gmail.com [School of Environmental Science and Engineering, Shandong University, Jinan, 250100 (China); Li, Hongli, E-mail: lihongli1225@163.com [Environmental Monitoring Central Station of Shandong Province, Jinan, 250101 (China); Yang, Minmin; Sun, Lei [School of Environmental Science and Engineering, Shandong University, Jinan, 250100 (China); Wang, Tao [Department of Civil and Structural Engineering, The Hong Kong Polytechnic University, Hong Kong (China); Wang, Wenxing [Environment Research Institute, Shandong University, Jinan, 250100 (China)

    2015-09-01

    Cloud water samples were collected from Mount Lushan, a high alpine area of southern China, and analyzed using GC–MS to investigate the concentration levels, seasonal variations, particle-dissolved phase partitioning, ecological risk of PAHs and its relationship to the atmosphere and rainwater. The average concentration of total (dissolved + particle) PAHs in cloud water was 819.90 ng/L, which ranged from 2.30 ng/L for DbA to 295.38 ng/L for PhA. PhA (33.11%) contributed the most individual PAHs, followed by Flu (28.24%). Distinct seasonal variations in the total PAHs measured in this research had a higher concentration during the spring and a lower concentration during the summer. When cloud events occurred, the concentration of the atmospheric PAHs of the two phases decreased. The contribution from the gaseous phase of total PAHs in the air to the dissolved phase in cloud water was up to 60.43%, but the particulate phase in the air only contributed 39.57% to the total scavenging. The contribution of total PAHs from the atmosphere to clouds is higher in the gaseous phase than in the particulate phase. A comparative study of the concentrations of cloud water and the closest rain water revealed that the PAH concentration in rainwater was 1.80 times less than that of cloud water and that the dominant individual compounds in cloud water and rainwater were PhA and Flu. A total of 81.27% of the PAHs in cloud samples and 72.21% of the PAHs in rain samples remained in the dissolved phase. Ecological risk assessment indicated that PAHs in cloud water in spring and summer caused a certain degree of ecosystem risk and the mean ecosystem risk in spring was higher than that in summer. - Highlights: • The site is in the high pollution emission area, having many sources of PAHs around. • Mount Lushan is a unique site for cloud chemistry monitoring. • Atmospheric PAHs mostly deposited and transferred into cloud water. • Special case showed PAHs are more concentrated in

  9. Cloud deposition of PAHs at Mount Lushan in southern China

    International Nuclear Information System (INIS)

    Wang, Ruixia; Wang, Yan; Li, Hongli; Yang, Minmin; Sun, Lei; Wang, Tao; Wang, Wenxing

    2015-01-01

    Cloud water samples were collected from Mount Lushan, a high alpine area of southern China, and analyzed using GC–MS to investigate the concentration levels, seasonal variations, particle-dissolved phase partitioning, ecological risk of PAHs and its relationship to the atmosphere and rainwater. The average concentration of total (dissolved + particle) PAHs in cloud water was 819.90 ng/L, which ranged from 2.30 ng/L for DbA to 295.38 ng/L for PhA. PhA (33.11%) contributed the most individual PAHs, followed by Flu (28.24%). Distinct seasonal variations in the total PAHs measured in this research had a higher concentration during the spring and a lower concentration during the summer. When cloud events occurred, the concentration of the atmospheric PAHs of the two phases decreased. The contribution from the gaseous phase of total PAHs in the air to the dissolved phase in cloud water was up to 60.43%, but the particulate phase in the air only contributed 39.57% to the total scavenging. The contribution of total PAHs from the atmosphere to clouds is higher in the gaseous phase than in the particulate phase. A comparative study of the concentrations of cloud water and the closest rain water revealed that the PAH concentration in rainwater was 1.80 times less than that of cloud water and that the dominant individual compounds in cloud water and rainwater were PhA and Flu. A total of 81.27% of the PAHs in cloud samples and 72.21% of the PAHs in rain samples remained in the dissolved phase. Ecological risk assessment indicated that PAHs in cloud water in spring and summer caused a certain degree of ecosystem risk and the mean ecosystem risk in spring was higher than that in summer. - Highlights: • The site is in the high pollution emission area, having many sources of PAHs around. • Mount Lushan is a unique site for cloud chemistry monitoring. • Atmospheric PAHs mostly deposited and transferred into cloud water. • Special case showed PAHs are more concentrated in

  10. Kandungan Senyawa Polisiklik Aromatik Hidrokarbon (PAH di Teluk Jakarta (Polycyclic Aromatic Compounds Hydrocarbons (PAH Content in Jakarta Bay

    Directory of Open Access Journals (Sweden)

    Fasmi Ahmad

    2013-07-01

    Full Text Available Perairan Teluk Jakarta menerima limbah yang berasal dari darat maupun perairan itu sendiri. Salah satu limbah tersebut adalah senyawa organik Polisiklik Aromatik Hidrokarbon (PAH yang merupakan senyawa organik bersifat toksik terhadap biota laut. Penelitian dilakukan untuk mengetahui kandungan PAH air laut dan sedimen dalam kaitannya dengan kehidupan biota laut serta mengetahui sumber senyawa tersebut. Pengukuran dilakukan bulan Maret 2011. Contoh air laut diambil dengan water sampler dan contoh sedimen dengan grab pada 15 stasiun. Kadar PAH dianalisa dengan Gas Chromatography-Flame Ionization Detector. Hasil penelitian menunjukkan kadar PAH air laut di Teluk Jakarta Bagian Barat > Bagian Tengah > Bagian Timur. Kandungan PAH di Teluk Jakarta Bagian Barat berkisar 201,57-474,68 ppb dengan total PAH 1404,68 ppb, di Bagian Tengah 104,61-337,07 ppb dengan total 825,63 ppb, dan di Bagian Timur 112,91-370,79 ppb dengan total 806,73 ppb. Data ini menunjukkan Teluk Jakarta Bagian Barat lebih banyak menerima masukan limbah yang mengandung PAH. Sedangkan Kadar PAH sedimen di Teluk Jakarta Bagian Timur > Bagian Tengah > Bagian Barat. Kadar PAH di Teluk Jakarta Bagian Barat berkisar 1,92-64,241 ppm dengan total 107,931 ppm, di Bagian Tengah 16,14-77,71 ppm dengan total 170,61 ppm, dan di Bagian Timur 8,72-115,39 ppm dengan total 252,25 ppm. Data ini menunjukkan sedimen di Teluk Jakarta Bagian Timur lebih banyak mengakumulasi limbah yang mengandung PAH. Sumber PAH dalam air laut dan sedimen ini berasal dari berbagai sumber yakni pembakaran bahan organik, pembakaran minyak bumi, dan tumpahan minyak. Kadar PAH dalam air laut di Teluk Jakarta ini telah melebihi Nilai Ambang Batas yang ditetapkan oleh KMNLH untuk biota laut, dan Nilai Ambang Batas untuk sedimen yang ditetapkan oleh Handbook for Sediment Quality Assessment. Kata kunci: Teluk Jakarta, Polisiklik Aromatik Hidrokarbon, PAH, polusi Jakarta Bay receives various kinds of waste both from land and waters

  11. Enhanced bioremediation of PAH contaminated soils from coal processing sites

    International Nuclear Information System (INIS)

    Joshi, M.M.; Lee, S.

    1995-01-01

    The polycyclic aromatic hydrocarbons (PAH) are a potential hazard to health due to their carcinogenic, mutagenic nature and acute toxicity and there is an imminent need for remediation of PAH contaminated soils abounding the several coke oven and town gas sites. Aerobic biological degradation of PAHs is an innovative technology and has shown high decontamination efficiencies, complete mineralization of contaminants, and is environmentally safe. The present study investigates the remediation of PAH contaminated soils achieved using Acinetobacter species and fungal strain Phanerochaete Chrysosporium. The soil used for the experiments was an industrially contaminated soil obtained from Alberta Research Council (ARC) primary cleanup facility, Alberta, Canada. Soil characterization was done using High Performance Liquid Chromatography (HPLC) to qualitatively and quantitatively determine the contaminants in the soil. Artificially contaminated soil was also used for some experiments. All the experiments were conducted under completely mixed conditions with suitable oxygen and nutrient amendments. The removal efficiency obtained for various PAHs using the two microorganisms was compared

  12. Electrochemical Oxidation of PAHs in Water from Harbor Sediment Purification

    DEFF Research Database (Denmark)

    Muff, Jens; Søgaard, Erik Gydesen

    2010-01-01

    generated oxidant solution with a free chlorine concentration of 2 gL-1. Both strategies resulted in a successful degradation of 5 PAHs to fulfil the discharge limit on 0.010 µgL-1. The intermixing-with-oxidant approach can also be applied as a method to address the actual sediment matrix....... of the discharge water addressing primarily polycyclic aromatic hydrocarbons (PAHs). PAHs are by-products of incomplete combustion of organic materials with recalcitrant and strong mutagenic/carcinogenic properties, due to their benzene analogue structures. PAHs are hydrophobic compounds and their persistence...... evidence for the importance of the indirect oxidation mechanism in the degradation of the PAHs. The proof-of-concept study was conducted both by a direct treatment approach and an intermixing-with-oxidant approach, where the contaminated water was intermixed in different ratios with an electrochemically...

  13. The Virtual Diphoton Excess

    CERN Document Server

    Stolarski, Daniel

    2016-01-01

    Interpreting the excesses around 750 GeV in the diphoton spectra to be the signal of a new heavy scalar decaying to photons, we point out the possibility of looking for correlated signals with virtual photons. In particular, we emphasize that the effective operator that generates the diphoton decay will also generate decays to two leptons and a photon, as well as to four leptons, independently of the new resonance couplings to $Z\\gamma$ and $ZZ$. Depending on the relative sizes of these effective couplings, we show that the virtual diphoton component can make up a sizable, and sometimes dominant, contribution to the total $2\\ell \\gamma$ and $4\\ell$ partial widths. We also discuss modifications to current experimental cuts in order to maximize the sensitivity to these virtual photon effects. Finally, we briefly comment on prospects for channels involving other Standard Model fermions as well as more exotic decay possibilities of the putative resonance.

  14. Abundance, Excess, Waste

    Directory of Open Access Journals (Sweden)

    Rox De Luca

    2016-02-01

    Her recent work focuses on the concepts of abundance, excess and waste. These concerns translate directly into vibrant and colourful garlands that she constructs from discarded plastics collected on Bondi Beach where she lives. The process of collecting is fastidious, as is the process of sorting and grading the plastics by colour and size. This initial gathering and sorting process is followed by threading the components onto strings of wire. When completed, these assemblages stand in stark contrast to the ease of disposability associated with the materials that arrive on the shoreline as evidence of our collective human neglect and destruction of the environment around us. The contrast is heightened by the fact that the constructed garlands embody the paradoxical beauty of our plastic waste byproducts, while also evoking the ways by which those byproducts similarly accumulate in randomly assorted patterns across the oceans and beaches of the planet.

  15. Topiramate Induced Excessive Sialorrhea

    Directory of Open Access Journals (Sweden)

    Ersel Dag

    2015-11-01

    Full Text Available It is well-known that drugs such as clozapine and lithium can cause sialorrhea. On the other hand, topiramate has not been reported to induce sialorrhea. We report a case of a patient aged 26 who was given antiepileptic and antipsychotic drugs due to severe mental retardation and intractable epilepsy and developed excessive sialorrhea complaint after the addition of topiramate for the control of seizures. His complaints continued for 1,5 years and ended after giving up topiramate. We presented this case since it was a rare sialorrhea case induced by topiramate. Clinicians should be aware of the possibility of sialorrhea development which causes serious hygiene and social problems when they want to give topiramate to the patients using multiple drugs.

  16. Infrared Spectroscopy of Matrix-Isolated Polycyclic Aromatic Hydrocarbon Cations. 3. The Polyacenes Anthracene, Tetracene, and Pentacene

    Science.gov (United States)

    Hudgins, D. M.; Allamandola, L. J.

    1995-01-01

    Gaseous, ionized Polycyclic Aromatic Hydrocarbons (PAH's) are thought to be responsible for a very common family of interstellar infrared emission bands. Unfortunately, very little infrared spectroscopic data are available on ionized PAH's. Here we present the near- and mid-infrared spectra of the polyacene cations anthracene, tetracene, and pentacene. We also report the vibrational frequencies and relative intensities of the pentacene anion. The cation bands corresponding to the CC modes are typically about 10-20 times more intense than those of the CH out-of-plane bending vibrations. For the cations the CC stretching and CH in-plane bending modes give rise to bands which are an order of magnitude stronger than for the neutral species, and the CH out-of-plane bends produce bands which are 3-20 times weaker than in the neutral species. This behavior is similar to that found for most other PAH cations. The most intense PAH cation bands fall within the envelopes of the most intense interstellar features. The strongest absorptions in the polyacenes anthracene, tetracene, and pentacene tend to group around 1400 / cm (between about 1340 and 1500 / cm) and near 1180 /cm, regions of only moderate interstellar emission. These very strong polyacene bands tend to fall in gaps in the spectra of the other PAH cations studied to date suggesting that while PAHs with polyacene structures may contribute to specific regions of the interstellar emission spectra, they are not dominant members of the interstellar PAH family.

  17. Infrared Spectroscopy of Matrix-Isolated Polycyclic Aromatic Hydrocarbon Cations. 3; The Polyacenes Anthracene, Tetracence, and Pentacene

    Science.gov (United States)

    Hudgins, D. M.; Allamandola, L. J.

    1995-01-01

    Gaseous, ionized polycyclic aromatic hydrocarbons (PAHS) are thought to be responsible for a very common family of interstellar infrared emission bands. Unfortunately, very little infrared spectroscopic data are available on ionized PAHS. Here we present the near- and mid-infrared spectra of the polyacene cations anthracene, tetracene, and pentacene. We also report the vibrational frequencies and relative intensities of the pentacene anion. The cation bands corresponding to the CC modes are typically about 10-20 times more intense than those of the CH out-of-plane bending vibrations. For the cations the CC stretching and CH in-plane bending modes give rise to bands which are an order of magnitude stronger than for the neutral species, and the CH out-of-plane bends produce bands which are 3-20 times weaker than in the neutral species. This behavior is similar to that found for most other PAH cations. The most intense PAH cation bands fall within the envelopes of the most intense interstellar features. The strongest absorptions in the polyacenes anthracene, tetracene, and pentacene tend to group around 1400/cm (between about 1340 and 1500/cm) and near 1180/cm, regions of only moderate interstellar emission. These very strong polyacene bands tend to fall in gaps in the spectra of the other PAH cations studied to date suggesting that while PAHs with polyacene structures may contribute to specific regions of the interstellar emission spectra, they are not dominant members of the interstellar PAH family.

  18. Interstellar PAH in the Laboratory and in Space. What have we Learned from the New Generation of Laboratory and Observational Studies?

    Science.gov (United States)

    Salama, Farid

    2005-01-01

    Polycyclic Aromatic Hydrocarbons (PAHs) are an important and ubiquitous component of carbon-bearing materials in space. PAHs are the best-known candidates to account for the IR emission bands (UIR bands) and PAH spectral features are now being used as new probes of the ISM. PAHs are also thought to be among the carriers of the diffuse interstellar absorption bands (DIBs). In the model dealing with the interstellar spectral features, PAHs are present as a mixture of radicals, ions and neutral species. PAH ionization states reflect the ionization balance of the medium while PAH size, composition, and structure reflect the energetic and chemical history of the medium. A major challenge for laboratory astrophysics is to reproduce (in a realistic way) the physical conditions that exist in the emission and/or absorption interstellar zones. An extensive laboratory program has been developed at NASA Ames to assess the physical and chemical properties of PAHs in such environments and to describe how they influence the radiation and energy balance in space and the interstellar chemistry. In particular, laboratory experiments provide measurements of the spectral characteristics of interstellar PAH analogs from the ultraviolet and visible range to the infrared range for comparison with astronomical data. This paper will focus on the recent progress made in the laboratory to measure the direct absorption spectra of neutral and ionized PAHs in the gas phase in the near-UV and visible range in astrophysically relevant environments. These measurements provide data on PAHs and nanometer-sized particles that can now be directly compared to astronomical observations. The harsh physical conditions of the IS medium - characterized by a low temperature, an absence of collisions and strong VUV radiation fields - are simulated in the laboratory by associating a molecular beam with an ionizing discharge to generate a cold plasma expansion. PAH ions are formed from the neutral precursors in

  19. Polycyclic Aromatic Hydrocarbon (PAH) and Oxygenated PAH (OPAH) Air–Water Exchange during the Deepwater Horizon Oil Spill

    Science.gov (United States)

    2015-01-01

    Passive sampling devices were used to measure air vapor and water dissolved phase concentrations of 33 polycyclic aromatic hydrocarbons (PAHs) and 22 oxygenated PAHs (OPAHs) at four Gulf of Mexico coastal sites prior to, during, and after shoreline oiling from the Deepwater Horizon oil spill (DWH). Measurements were taken at each site over a 13 month period, and flux across the water–air boundary was determined. This is the first report of vapor phase and flux of both PAHs and OPAHs during the DWH. Vapor phase sum PAH and OPAH concentrations ranged between 1 and 24 ng/m3 and 0.3 and 27 ng/m3, respectively. PAH and OPAH concentrations in air exhibited different spatial and temporal trends than in water, and air–water flux of 13 individual PAHs were strongly associated with the DWH incident. The largest PAH volatilizations occurred at the sites in Alabama and Mississippi in the summer, each nominally 10 000 ng/m2/day. Acenaphthene was the PAH with the highest observed volatilization rate of 6800 ng/m2/day in September 2010. This work represents additional evidence of the DWH incident contributing to air contamination, and provides one of the first quantitative air–water chemical flux determinations with passive sampling technology. PMID:25412353

  20. Polycyclic aromatic hydrocarbon (PAH) and oxygenated PAH (OPAH) air-water exchange during the deepwater horizon oil spill.

    Science.gov (United States)

    Tidwell, Lane G; Allan, Sarah E; O'Connell, Steven G; Hobbie, Kevin A; Smith, Brian W; Anderson, Kim A

    2015-01-06

    Passive sampling devices were used to measure air vapor and water dissolved phase concentrations of 33 polycyclic aromatic hydrocarbons (PAHs) and 22 oxygenated PAHs (OPAHs) at four Gulf of Mexico coastal sites prior to, during, and after shoreline oiling from the Deepwater Horizon oil spill (DWH). Measurements were taken at each site over a 13 month period, and flux across the water-air boundary was determined. This is the first report of vapor phase and flux of both PAHs and OPAHs during the DWH. Vapor phase sum PAH and OPAH concentrations ranged between 1 and 24 ng/m(3) and 0.3 and 27 ng/m(3), respectively. PAH and OPAH concentrations in air exhibited different spatial and temporal trends than in water, and air-water flux of 13 individual PAHs were strongly associated with the DWH incident. The largest PAH volatilizations occurred at the sites in Alabama and Mississippi in the summer, each nominally 10,000 ng/m(2)/day. Acenaphthene was the PAH with the highest observed volatilization rate of 6800 ng/m(2)/day in September 2010. This work represents additional evidence of the DWH incident contributing to air contamination, and provides one of the first quantitative air-water chemical flux determinations with passive sampling technology.

  1. Biodegradation aspects of Polycyclic Aromatic Hydrocarbons (PAHs): A review

    International Nuclear Information System (INIS)

    Haritash, A.K.; Kaushik, C.P.

    2009-01-01

    PAHs are aromatic hydrocarbons with two or more fused benzene rings with natural as well as anthropogenic sources. They are widely distributed environmental contaminants that have detrimental biological effects, toxicity, mutagenecity and carcinogenicity. Due to their ubiquitous occurrence, recalcitrance, bioaccumulation potential and carcinogenic activity, the PAHs have gathered significant environmental concern. Although PAH may undergo adsorption, volatilization, photolysis, and chemical degradation, microbial degradation is the major degradation process. PAH degradation depends on the environmental conditions, number and type of the microorganisms, nature and chemical structure of the chemical compound being degraded. They are biodegraded/biotransformed into less complex metabolites, and through mineralization into inorganic minerals, H 2 O, CO 2 (aerobic) or CH 4 (anaerobic) and rate of biodegradation depends on pH, temperature, oxygen, microbial population, degree of acclimation, accessibility of nutrients, chemical structure of the compound, cellular transport properties, and chemical partitioning in growth medium. A number of bacterial species are known to degrade PAHs and most of them are isolated from contaminated soil or sediments. Pseudomonas aeruginosa, Pseudomons fluoresens, Mycobacterium spp., Haemophilus spp., Rhodococcus spp., Paenibacillus spp. are some of the commonly studied PAH-degrading bacteria. Lignolytic fungi too have the property of PAH degradation. Phanerochaete chrysosporium, Bjerkandera adusta, and Pleurotus ostreatus are the common PAH-degrading fungi. Enzymes involved in the degradation of PAHs are oxygenase, dehydrogenase and lignolytic enzymes. Fungal lignolytic enzymes are lignin peroxidase, laccase, and manganese peroxidase. They are extracellular and catalyze radical formation by oxidation to destabilize bonds in a molecule. The biodegradation of PAHs has been observed under both aerobic and anaerobic conditions and the rate can

  2. Biodegradation aspects of Polycyclic Aromatic Hydrocarbons (PAHs): A review

    Energy Technology Data Exchange (ETDEWEB)

    Haritash, A.K., E-mail: akharitash@gmail.com [Department of Environmental Science and Engineering, Guru Jambheshwar University of Science and Technology, Hisar, Haryana (India); Kaushik, C.P. [Department of Environmental Science and Engineering, Guru Jambheshwar University of Science and Technology, Hisar, Haryana (India)

    2009-09-30

    PAHs are aromatic hydrocarbons with two or more fused benzene rings with natural as well as anthropogenic sources. They are widely distributed environmental contaminants that have detrimental biological effects, toxicity, mutagenecity and carcinogenicity. Due to their ubiquitous occurrence, recalcitrance, bioaccumulation potential and carcinogenic activity, the PAHs have gathered significant environmental concern. Although PAH may undergo adsorption, volatilization, photolysis, and chemical degradation, microbial degradation is the major degradation process. PAH degradation depends on the environmental conditions, number and type of the microorganisms, nature and chemical structure of the chemical compound being degraded. They are biodegraded/biotransformed into less complex metabolites, and through mineralization into inorganic minerals, H{sub 2}O, CO{sub 2} (aerobic) or CH{sub 4} (anaerobic) and rate of biodegradation depends on pH, temperature, oxygen, microbial population, degree of acclimation, accessibility of nutrients, chemical structure of the compound, cellular transport properties, and chemical partitioning in growth medium. A number of bacterial species are known to degrade PAHs and most of them are isolated from contaminated soil or sediments. Pseudomonas aeruginosa, Pseudomons fluoresens, Mycobacterium spp., Haemophilus spp., Rhodococcus spp., Paenibacillus spp. are some of the commonly studied PAH-degrading bacteria. Lignolytic fungi too have the property of PAH degradation. Phanerochaete chrysosporium, Bjerkandera adusta, and Pleurotus ostreatus are the common PAH-degrading fungi. Enzymes involved in the degradation of PAHs are oxygenase, dehydrogenase and lignolytic enzymes. Fungal lignolytic enzymes are lignin peroxidase, laccase, and manganese peroxidase. They are extracellular and catalyze radical formation by oxidation to destabilize bonds in a molecule. The biodegradation of PAHs has been observed under both aerobic and anaerobic conditions

  3. PAH related effects on fish in sedimentation ponds for road runoff and potential transfer of PAHs from sediment to biota.

    Science.gov (United States)

    Grung, Merete; Petersen, Karina; Fjeld, Eirik; Allan, Ian; Christensen, Jan H; Malmqvist, Linus M V; Meland, Sondre; Ranneklev, Sissel

    2016-10-01

    Road runoff is an important source of pollution to the aquatic environment, and sedimentation ponds have been installed to mitigate effects on the aquatic environment. The purpose of this study was to investigate if a) fish from sedimentation ponds were affected by road pollution and; b) the transfer of PAHs from road runoff material to aquatic organisms was substantial. Minnow from a sedimentation pond (Skullerud) near Oslo (Norway) had higher levels of CYP1A enzyme and DNA stand breaks than minnow from the nearby river, but high concentrations of PAH-metabolites in bile revealed that both populations were highly exposed. Principal component analysis revealed that CYP1A and age of fish were correlated, while levels of PAH-metabolites were not correlated to CYP1A or DNA damage. Minnow from a lake un-affected by traffic had much lower levels of PAH-metabolites than the exposed fish, and also an improved condition. The latter results indicate that fish health was affected by road runoff. A closer investigation of PAH levels of the ecosystems of two sedimentation ponds (Skullerud and Vassum) and nearby environments were conducted. The concentration of the 16 EPA PAHs in sediments of the sedimentation ponds were high (1900-4200ngg(-1)), and even higher levels were observed in plants. Principal component analysis of selected ion chromatograms of PAHs showed a clear separation of plants vs. sediments. The plants preferentially accumulated the high molecular PAHs, both from sedimentation ponds with a petrogenic PAH isomer ratio in sediments; and from a lake with pyrogenic PAH isomer ratio in sediments. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Infrared astronomy

    International Nuclear Information System (INIS)

    Setti, G.; Fazio, G.

    1978-01-01

    This volume contains lectures describing the important achievements in infrared astronomy. The topics included are galactic infrared sources and their role in star formation, the nature of the interstellar medium and galactic structure, the interpretation of infrared, optical and radio observations of extra-galactic sources and their role in the origin and structure of the universe, instrumental techniques and a review of future space observations. (C.F.)

  5. The Role of Human Aldo-Keto Reductases in the Metabolic Activation and Detoxication of Polycyclic Aromatic Hydrocarbons: Interconversion of PAH Catechols and PAH o-Quinones

    Science.gov (United States)

    Zhang, Li; Jin, Yi; Huang, Meng; Penning, Trevor M.

    2012-01-01

    Polycyclic aromatic hydrocarbons (PAH) are ubiquitous environmental pollutants. They are procarcinogens requiring metabolic activation to elicit their deleterious effects. Aldo-keto reductases (AKR) catalyze the oxidation of proximate carcinogenic PAH trans-dihydrodiols to yield electrophilic and redox-active PAH o-quinones. AKRs are also found to be capable of reducing PAH o-quinones to form PAH catechols. The interconversion of o-quinones and catechols results in the redox-cycling of PAH o-quinones to give rise to the generation of reactive oxygen species and subsequent oxidative DNA damage. On the other hand, PAH catechols can be intercepted through phase II metabolism by which PAH o-quinones could be detoxified and eliminated. The aim of the present review is to summarize the role of human AKRs in the metabolic activation/detoxication of PAH and the relevance of phase II conjugation reactions to human lung carcinogenesis. PMID:23162467

  6. Decontamination of soils containing PAHs by electroremediation: a review.

    Science.gov (United States)

    Pazos, M; Rosales, E; Alcántara, T; Gómez, J; Sanromán, M A

    2010-05-15

    During the last years, the anthropogenic sources have contributed to organic compound penetration into the environment. One large group of persistent and toxic contaminants is the hydrophobic organic contaminants. Among them, polycyclic aromatic hydrocarbons (PAHs) have been recognized as a representative group of these pollutants with low solubility. In this paper, it is showed the electroremediation of soil contaminated with PAHs as an alternative, to organic compound removal. This technique, mainly used for heavy metal extraction, applies the electric current to promote the movement of contaminants. Nowadays the application of this technique alone or combined with other techniques as for example Fenton or bioremediation is taking fine results to PAHs removal. Although the PAHs soil decontamination by means of the electric field is in an initial stage, many researchers have demonstrated the treatment effectiveness. This paper describes the foremost principles to carry out the electroremediation of soils contaminated with PAHs, just like the different alternatives to improve the electroremediation of PAHs and also the new methodologies of PAHs removal by using hybrid technologies. Copyright (c) 2009 Elsevier B.V. All rights reserved.

  7. PAH diagnostic ratios for the identification of pollution emission sources

    International Nuclear Information System (INIS)

    Tobiszewski, Marek; Namieśnik, Jacek

    2012-01-01

    Polycyclic aromatic hydrocarbon (PAH) diagnostic ratios have recently come into common use as a tool for identifying and assessing pollution emission sources. Some diagnostic ratios are based on parent PAHs, others on the proportions of alkyl-substituted to non-substituted molecules. The ratios are applicable to PAHs determined in different environmental media: air (gas + particle phase), water, sediment, soil, as well as biomonitor organisms such as leaves or coniferous needles, and mussels. These ratios distinguish PAH pollution originating from petroleum products, petroleum combustion and biomass or coal burning. The compounds involved in each ratio have the same molar mass, so it is assumed they have similar physicochemical properties. Numerous studies show that diagnostic ratios change in value to different extents during phase transfers and environmental degradation. The paper reviews applications of diagnostic ratios, comments on their use and specifies their limitations. - Highlights: ► PAH diagnostic ratios may identify pollution coming from petroleum spills, fuel combustion and coal or biomass burning. ► They are sensitive to changes during PAHs environmental fate processes. ► Some diagnostic ratios are of limited value due to fast photodegradation of one of the compounds. - The paper reviews PAH diagnostic ratios that are applied to identify pollution emission originating from petroleum products, fuel combustion or coal and biomass burning.

  8. PAH emissions from coal combustion and waste incineration.

    Science.gov (United States)

    Hsu, Wei Ting; Liu, Mei Chen; Hung, Pao Chen; Chang, Shu Hao; Chang, Moo Been

    2016-11-15

    The characteristics of PAHs that are emitted by a municipal waste incinerator (MWI) and coal-fired power plant are examined via intensive sampling. Results of flue gas sampling reveal the potential for PAH formation within the selective catalytic reduction (SCR) system of a coal-fired power plant. In the large-scale MWI, the removal efficiency of PAHs achieved with the pilot-scaled catalytic filter (CF) exceeds that achieved by activated carbon injection with a bag filter (ACI+BF) owing to the effective destruction of gas-phase contaminants by a catalyst. A significantly lower PAH concentration (1640ng/g) was measured in fly ash from a CF module than from an ACI+BF system (5650ng/g). Replacing the ACI+BF system with CF technology would significantly reduce the discharge factor (including emission and fly ash) of PAHs from 251.6 to 77.8mg/ton-waste. The emission factors of PAHs that are obtained using ACI+BF and the CF system in the MWI are 8.05 and 7.13mg/ton, respectively. However, the emission factor of MWI is significantly higher than that of coal-fired power plant (1.56mg/ton). From the perspective of total environmental management to reduce PAH emissions, replacing the original ACI+BF process with a CF system is expected to reduce environmental impact thereof. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. PAH exposure through soil ingestion: Combining digestion models and bioassays

    Energy Technology Data Exchange (ETDEWEB)

    Wiele, T.R. van de; Verstraete, W. [Ghent University (BE).Laboratory Microbial Ecology and Technology (LabMET); Siciliano, S.D. [University of Saskatchewan (Canada). Department of Soil Science

    2003-07-01

    Exposure to environmental contaminants through soil ingestion is an important issue in current health risk assessment. Polycyclic aromatic hydrocarbons (PAH) or their metabolites pose risks to humans due to their toxic, mutagenic, carcinogenic or even (anti)estrogenic properties. PAH mobilization from a soil matrix (49.1{+-}1.5 mg PAH/kg DW) was assessed using a Simulator of the Human Intestinal Microbial Ecosystem (SHIME). PAH GC-MS analysis was performed on the pellet and supernatant of SHIME digests and gave 101, 92, 89 and 97% recovery for water, stomach, duodenal and colon digests, respectively. PAH release was highest for the water extract (0.51%) and the stomach digestion (0.44%). Lower mobilized fractions in the duodenum (0.13%) and colon (0.30%) digests could be attributed to PAH complexation with bile salts, dissolved organic matter or colon microbiota. The digestion model provides us with relevant information to what extent soil bound PAHs are mobilized in the gastrointestinal tract and thus reach the gut wall, prior to absorption. (orig.)

  10. Distribution of polycyclic aromatic hydrocarbons (PAHs) in rivers and estuaries in Malaysia: a widespread input of petrogenic PAHs.

    Science.gov (United States)

    Zakaria, Mohamad Pauzi; Takada, Hideshige; Tsutsumi, Shinobu; Ohno, Kei; Yamada, Junya; Kouno, Eriko; Kumata, Hidetoshi

    2002-05-01

    This is the first publication on the distribution and sources of polycyclic aromatic hydrocarbons (PAHs) in riverine and coastal sediments in South East Asia where the rapid transfer of land-based pollutants into aquatic environments by heavy rainfall and runoff waters is of great concern. Twenty-nine Malaysian riverine and coastal sediments were analyzed for PAHs (3-7 rings) by gas chromatography mass spectrometry. Total PAHs concentrations in the sediment ranged from 4 to 924 ng/g. Alkylated homologues were abundant for all sediment samples. The ratio of the sum of methylphenanthrenes to phenanthrene (MP/P), an index of petrogenic PAHs contribution, was more than unity for 26 sediment samples and more than 3 for seven samples for urban rivers covering a broad range of locations. The MP/P ratio showed a strong correlation with the total PAHs concentrations, with an r2 value of 0.74. This ratio and all other compositional features indicated that Malaysian urban sediments are heavily impacted by petrogenic PAHs. This finding is in contrast to other studies reported in many industrialized countries where PAHs are mostly of pyrogenic origin. The MP/P ratio was also significantly correlated with higher molecular weight PAHs such as benzo[a]pyrene, suggesting unique PAHs source in Malaysia which contains both petrogenic PAHs and pyrogenic PAHs. PAHs and hopanes fingerprints indicated that used crankcase oil is one of the major contributors of the sedimentary PAHs. Two major routes of inputs to aquatic environments have been identified: (1) spillage and dumping of waste crankcase oil and (2) leakage of crankcase oils from vehicles onto road surfaces, with the subsequent washout by street runoff. N-Cyclohexyl-2-benzothiazolamine (NCBA), a molecular marker of street dust, was detected in the polluted sediments. NCBA and other biomarker profiles confirmed our hypothesis of the input from street dust contained the leaked crankcase oil. The fingerprints excluded crude oil

  11. Assessing risks to adults and preschool children posed by PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) during a biomass burning episode in Northern Thailand.

    Science.gov (United States)

    Pongpiachan, Siwatt; Tipmanee, Danai; Khumsup, Chukkapong; Kittikoon, Itthipon; Hirunyatrakul, Phoosak

    2015-03-01

    To investigate the potential cancer risk resulting from biomass burning, polycyclic aromatic hydrocarbons (PAHs) bound to fine particles (PM2.5) were assessed in nine administrative northern provinces (NNP) of Thailand, before (N-I) and after (N-II) a haze episode. The average values of Σ 3,4-ring PAHs and B[a] P Equivalent concentrations in world urban cities were significantly (p<0.05) much higher than those in samples collected from northern provinces during both sampling periods. Application of diagnostic binary ratios of PAHs underlined the predominant contribution of vehicular exhaust to PM2.5-bound PAH levels in NNP areas, even in the middle of the agricultural waste burning period. The proximity of N-I and N-II values in three-dimensional (3D) principal component analysis (PCA) plots also supports this conclusion. Although the excess cancer risk in NNP areas is much lower than those of other urban area and industrialized cities, there are nevertheless some concerns relating to adverse health impacts on preschool children due to non-dietary exposure to PAHs in home environments. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Infrared thermography

    CERN Document Server

    Meola, Carosena

    2012-01-01

    This e-book conveys information about basic IRT theory, infrared detectors, signal digitalization and applications of infrared thermography in many fields such as medicine, foodstuff conservation, fluid-dynamics, architecture, anthropology, condition monitoring, non destructive testing and evaluation of materials and structures.

  13. Biodegradation of PAHs by fungi in contaminated-soil containing ...

    African Journals Online (AJOL)

    PAH) benzo(a)anthracene, benzo(a) fluoranthene, benzo(a) pyrene, chrysene and phenanthrene in a soil that was sterilized and inoculated with the nonligninolytic fungi, Fusarium flocciferum and Trichoderma spp. and the ligninolytic fungi, ...

  14. Polycyclic Aromatic Hydrocarbons (PAHs) Content in Cattle Hides ...

    African Journals Online (AJOL)

    ADOWIE PERE

    ABSTRACT: Scrap rubber tyre is used as fuel for singeing animal carcasses in third world countries despite the fact that it can .... test method and the quantification of the PAH analytes using ... waste, SW-846 methods) with some modifications.

  15. PAHs sensitivity of picophytoplankton populations in the Red Sea

    KAUST Repository

    Kottuparambil, Sreejith; Agusti, Susana

    2018-01-01

    are higher than those reported for picophytoplankton from other oligotrophic marine waters and exceed by far the natural levels of PAHs in many oceans. Our findings reveal a possible adaptation of picophytoplankton populations to oil-related contaminants

  16. Enhanced PM10 bounded PAHs from shipping emissions

    Science.gov (United States)

    Pongpiachan, S.; Hattayanone, M.; Choochuay, C.; Mekmok, R.; Wuttijak, N.; Ketratanakul, A.

    2015-05-01

    Earlier studies have highlighted the importance of maritime transport as a main contributor of air pollutants in port area. The authors intended to investigate the effects of shipping emissions on the enhancement of PM10 bounded polycyclic aromatic hydrocarbons (PAHs) and mutagenic substances in an industrial area of Rayong province, Thailand. Daily PM10 speciation data across two air quality observatory sites in Thailand during 2010-2013 were collected. Diagnostic binary ratios of PAH congeners, analysis of variances (ANOVA), and principal component analysis (PCA) were employed to evaluate the enhanced genotoxicity of PM10 during the docking period. Significant increase of PAHs and mutagenic index (MI) of PM10 were observed during the docking period in both sampling sites. Although stationary sources like coal combustions from power plants and vehicular exhausts from motorway can play a great role in enhancing PAH concentrations, regulating shipping emissions from diesel engine in the port area like Rayong is predominantly crucial.

  17. Ambient water quality criteria for polycyclic aromatic hydrocarbons (PAHs)

    Energy Technology Data Exchange (ETDEWEB)

    Nagpal, N.K.

    1993-08-13

    Ambient water quality criteria are established for polyaromatic hydrocarbons (PAH) in British Columbia. Major sources of PAH in the atmosphere and aquatic environments include, for the atmosphere, forest and prairie fires, agricultural burning, refuse burning, enclosed incineration, and heating and power, and for the aquatic environment, petroleum spillage, atmospheric deposition, wastewaters, surface land runoff, and biosynthesis. Details are presented of PAH and their characteristics, forms and transformations, occurrence in the environment, drinking water concerns, aquatic life concerns, wildlife concerns, livestock water supply concerns, and irrigation concerns. Application of criteria for aquatic life is discussed including phototoxic vs long term criteria, assessment of existing water quality, setting water quality objectives, and PAH levels in smoked fish. 221 refs., 5 figs., 30 tabs.

  18. Mid-Infrared Spectral Properties of IR QSOs

    International Nuclear Information System (INIS)

    Xia, X. Y.; Cao, C.; Mao, S.; Deng, Z. G.

    2008-01-01

    We analyse mid-infrared (MIR) spectroscopic properties for 19 ultra-luminous infrared quasars (IR QSOs) in the local universe based on the spectra from the Infrared Spectrograph on board the Spitzer Space Telescope. The MIR properties of IR QSOs are compared with those of optically-selected Palomar-Green QSOs (PG QSOs) and ultra-luminous infrared galaxies (ULIRGs). The average MIR spectral features from ∼5 to 30 μm, including the spectral slopes, 6.2 μm PAH emission strengths and [NeII] 12.81 μm luminosities of IR QSOs, differ from those of PG QSOs. In contrast, IR QSOs and ULIRGs have comparable PAH and [NeII] luminosities. These results are consistent with IR QSOs being at a transitional stage from ULIRGs to classical QSOs. We also find the correlation between the EW (PAH 6.2 μm) and outflow velocities suggests that star formation activities are suppressed by feedback from AGNs and/or supernovae.

  19. Generation of polycyclic aromatic hydrocarbons (PAH during woodworking operations

    Directory of Open Access Journals (Sweden)

    Evin Danisman Bruschweiler

    2012-10-01

    Full Text Available Occupational exposures to wood dust have been associated with an elevated risk of sinonasal cancer (SNC. Wood dust is recognized as a human carcinogen but the specific cancer causative agent remains unknown. One possible explanation is a co-exposure to; wood dust and polycyclic aromatic hydrocarbons (PAHs. PAHs could be generated during incomplete combustion of wood due to heat created by use of power tools.To determine if PAHs are generated from wood during common woodworking operations, PAHs concentrations in wood dust samples collected in an experimental chamber operated under controlled conditions were analyzed. In addition, personal air samples from workers exposed to wood dust (n=30 were collected.Wood dust was generated using tree different power tools: vibrating sander, belt sander, and saw; and six wood materials: fir, Medium Density Fiberboard (MDF, beech, mahogany, oak and wood melamine. Monitoring of wood workers was carried out by means of personnel sampler device during wood working operations. We measured 21 PAHs concentrations in wood dust samples by capillary gas chromatographic-ion trap mass spectrometric analysis (GC-MS.Total PAH concentrations in wood dust varied greatly (0.24 – 7.95 ppm with the lowest being in MDF dust and the highest in wood melamine dust. Personal exposures to PAHs observed were between 37.5-119.8 ng m-3 among workers during wood working operations.Our results suggest that PAH exposures during woodworking operation are present and hence could play a role in the mechanism of cancer induction related to wood dust exposure.

  20. Water-Sediment Partition of Polycyclic Aromatic Hydrocarbons (PAHs) in Nansi Lake

    Science.gov (United States)

    Zhang, Guizhai; Diao, Youjiang

    2018-06-01

    Based on field data of polycyclic aromatic hydrocarbons (PAHs) in water and sediment in Nansi Lake. The concentrations and the partitioning characteristic of PAHs in the water and sediment were studied. The lgKd of high molecular weight PAHs were higher than the low molecular weight PAHs. The most of PAHs Kd values were negligible correlated with TOC, soluble salt, clay and pH of the sediment in Nansi Lake.

  1. Steps Toward Identifying PAHs: A Child's Garden of Recent Results

    Science.gov (United States)

    Hudgins, Douglas M.

    2005-01-01

    Based on over two decades of experimental, observational and theoretical studies by scientists around the world. It is now widely accepted that the composite emission of mixtures of vibrationally-excited PAHs and PAH ions can accommodate the general pattern of band positions, intensities, and profiles observed in the discreet IR emission features of carbon-rich interstellar dust, as well as the variations in those characteristics. These variations provide insight into the detailed nature of the emitting PAH population and reflect conditions within the emitting regions giving the population enormous potential as probes of astrophysical environments. Moreover, the ubiquity and abundance of this material has impacts that extend well beyond the IR. In this presentation we will examine recent, combined experimental, theoretical, and observational studies that indicate that nitrogen-substituted PAHs represent an important component of the interstellar dust population, and we will go on to explore some of the ramifications of this result. We will also explore the results of recent experimental studies of the strong, low-lying electronic transitions of ionized PAH ions in the Near-IR (0.7 - 2.5 microns) and explore the role that these transitions might play in pumping the PAH IR emission in regions of low-excitation.

  2. Reductions of PAH and Soot by Center Air Injection

    Directory of Open Access Journals (Sweden)

    Kazuhiro Yamamoto

    2014-07-01

    Full Text Available In this study, to reduce the amount of pollutant PAH and soot in the flame, we examined the burner system equipped with a center air injection. For this purpose, by using PAH-LIF and soot LII, we evaluated relative PAH and soot amounts in both the triple port burner and the conventional co-axial burner (double port burner to discuss effects of center air injection on the formation of PAH and soot. The fuel was propane. In the triple port burner, two different blue flames are observed near the burner rim, followed by bright luminous flames with soot. The flame length is longer when the fuel flow velocity is increased. On the other hand, the flame length is shorter with an increase in internal air flow velocity. As for PAH and soot, these amounts of the triple port burner are much smaller than those of the double port burner. For the triple port burner, due to the center air injection, the fuel consumption occurs in both inner and outer flames. On the other hand, for the double port burner, the oxygen is supplied from one side air, and as a result, the fuel consumption rate is relatively lower. Hence, by the center air injection, the fuel consumption is largely accelerated, resulting in the reduction of PAH and soot.

  3. The North Cape oil spill assessment: PAHs in oil

    International Nuclear Information System (INIS)

    Brown, J.; Boehm, P. D.; Hardestine, J. H.; Douglas, G. S.

    1997-01-01

    The North Cape oil spill in January 1996 resulted in the release of an estimated 827,000 gallons of No. 2 home heating oil into the nearshore turbulent waters of coastal Rhode Island. The oil was mixed into the water column and was transported on the surface as well as below the surface. Some of the spilled oil entered the coastal ponds behind the beaches. Sampling and chemical analysis for detailed suites of petroleum saturated and polycyclic aromatic hydrocarbons (PAHs) was undertaken as part of the assessment of the fate of the oil spill and of the exposure to the marine environment. The ponds were found to contain significant quantities of background petroleum hydrocarbons, including petrogenic PAHs and combustion PAHs. Initial assessment pointed (incorrectly as it turned out) to widespread contamination due only to the North Cape spill. Application of advanced chemical fingerprinting approaches, and geochemical biomarker data illustrated that many of the PAHs consisted of combustion-related 4- and 5-ringed PAHs, attributable to diesel fuel used routinely by boats in the area. The analysis demonstrated that the use of non-specific total PAH data and insufficient fingerprinting and allocation of petrogenic residues has the potential to overestimate contamination and hence injury to the environment in similar oil spill situations

  4. Study of remobilization polycyclic aromatic hydrocarbons (PAHs) in contaminated matrices

    International Nuclear Information System (INIS)

    Belkessam, L.; Vessigaud, S.; Laboudigue, A.; Vessigaud, S.; Perrin-Ganier, C.; Schiavon, M.; Denys, S.

    2005-01-01

    Polycyclic aromatic hydrocarbons (PAHs) originate from many pyrolysis processes. They are widespread environmental pollutants because some of them present toxic and genotoxic properties. In coal pyrolysis sites such as former manufactured gas plants and coke production plants, coal tar is a major source of PAHs. The management of such sites requires better understanding of the mechanisms that control release of PAHs to the biosphere. Determining total PAH concentrations is not sufficient since it does not inform about the pollutants availability to environmental processes. The fate and transport of PAHs in soil are governed by sorption and microbial processes which are well documented. Globally, enhancing retention of the compounds by a solid matrix reduces the risk of pollutant dispersion, but decreases their accessibility to microbial microflora. Conversely, the remobilization of organics from contaminated solid matrices represents a potential hazard since these pollutants can reach groundwater resources. However the available data are often obtained from laboratory experiments in which many field parameters can not be taken into account (long term, temperature, co-pollution, ageing phenomenon, heterogenous distribution of pollution). The present work focuses on the influence assessment and understanding of some of these parameters on PAHs remobilization from heavily polluted matrices in near-field conditions (industrial contaminated matrices, high contact time, ..). Results concerning effects of temperature and physical state of pollution (dispersed among the soil or condensed in small clusters or in coal tar) are presented. (authors)

  5. Enhanced Accessibility of Polycyclic Aromatic Hydrocarbons (PAHs) and Heterocyclic PAHs in Industrially Contaminated Soil after Passive Dosing of a Competitive Sorbate

    DEFF Research Database (Denmark)

    Humel, Stefan; Nørgaard Schmidt, Stine; Sumetzberger-Hasinger, Marion

    2017-01-01

    To assess the exposure to polycyclic aromatic hydrocarbons (PAHs) it is important to understand the binding mechanisms between specific soil constituents and the organic pollutant. In this study, sorptive bioaccessibility extraction (SBE) was applied to quantify the accessible PAH fraction...... in industrially contaminated soil with and without passive dosing of a competitive sorbate. SBE experiments revealed an accessible PAH fraction of 41 ± 1% (∑16 US EPA PAHs + 5 further PAHs). The passive dosing of toluene below its saturation level revealed competitive binding and resulted in an average increase.......4% PAH. We explain increased PAH desorption after addition of toluene by competitive adsorption to high-affinity sorption sites while acknowledging that toluene could additionally have increased PAH mobility within the soil matrix. Findings suggest that the presence of copollutants at contaminated sites...

  6. Bioremediation of PAH contaminated soil samples

    International Nuclear Information System (INIS)

    Joshi, M.M.; Lee, S.

    1994-01-01

    Soils contaminated with polynuclear aromatic hydrocarbons (PAHs) pose a hazard to life. The remediation of such sites can be done using physical, chemical, and biological treatment methods or a combination of them. It is of interest to study the decontamination of soil using bioremediation. The experiments were conducted using Acinetobacter (ATCC 31012) at room temperature without pH or temperature control. In the first series of experiments, contaminated soil samples obtained from Alberta Research Council were analyzed to determine the toxic contaminant and their composition in the soil. These samples were then treated using aerobic fermentation and removal efficiency for each contaminant was determined. In the second series of experiments, a single contaminant was used to prepare a synthetic soil sample. This sample of known composition was then treated using aerobic fermentation in continuously stirred flasks. In one set of flasks, contaminant was the only carbon source and in the other set, starch was an additional carbon source. In the third series of experiments, the synthetic contaminated soil sample was treated in continuously stirred flasks in the first set and in fixed bed in the second set and the removal efficiencies were compared. The removal efficiencies obtained indicated the extent of biodegradation for various contaminants, the effect of additional carbon source, and performance in fixed bed without external aeration

  7. Does excessive pronation cause pain?

    DEFF Research Database (Denmark)

    Olesen, C G; Nielsen, Rasmus Gottschalk N; Rathleff, Michael Skovdal

    2008-01-01

    Excessive pronation could be an inborn abnormality or an acquired foot disorder caused by overuse, inadequate supported shoes or inadequate foot training. When the muscles and ligaments of the foot are insufficient it can cause an excessive pronation of the foot. The current treatment consist of ...

  8. THE NASA AMES POLYCYCLIC AROMATIC HYDROCARBON INFRARED SPECTROSCOPIC DATABASE: THE COMPUTED SPECTRA

    International Nuclear Information System (INIS)

    Bauschlicher, C. W.; Ricca, A.; Boersma, C.; Mattioda, A. L.; Cami, J.; Peeters, E.; Allamandola, L. J.; Sanchez de Armas, F.; Puerta Saborido, G.; Hudgins, D. M.

    2010-01-01

    The astronomical emission features, formerly known as the unidentified infrared bands, are now commonly ascribed to polycyclic aromatic hydrocarbons (PAHs). The laboratory experiments and computational modeling done at the NASA Ames Research Center to create a collection of PAH IR spectra relevant to test and refine the PAH hypothesis have been assembled into a spectroscopic database. This database now contains over 800 PAH spectra spanning 2-2000 μm (5000-5 cm -1 ). These data are now available on the World Wide Web at www.astrochem.org/pahdb. This paper presents an overview of the computational spectra in the database and the tools developed to analyze and interpret astronomical spectra using the database. A description of the online and offline user tools available on the Web site is also presented.

  9. Phototransformation rate constants of PAHs associated with soot particles

    International Nuclear Information System (INIS)

    Kim, Daekyun; Young, Thomas M.; Anastasio, Cort

    2013-01-01

    Photodegradation is a key process governing the residence time and fate of polycyclic aromatic hydrocarbons (PAHs) in particles, both in the atmosphere and after deposition. We have measured photodegradation rate constants of PAHs in bulk deposits of soot particles illuminated with simulated sunlight. The photodegradation rate constants at the surface (k p 0 ), the effective diffusion coefficients (D eff ), and the light penetration depths (z 0.5 ) for PAHs on soot layers of variable thickness were determined by fitting experimental data with a model of coupled photolysis and diffusion. The overall disappearance rates of irradiated low molecular weight PAHs (with 2–3 rings) on soot particles were influenced by fast photodegradation and fast diffusion kinetics, while those of high molecular weight PAHs (with 4 or more rings) were apparently controlled by either the combination of slow photodegradation and slow diffusion kinetics or by very slow diffusion kinetics alone. The value of z 0.5 is more sensitive to the soot layer thickness than the k p 0 value. As the thickness of the soot layer increases, the z 0.5 values increase, but the k p 0 values are almost constant. The effective diffusion coefficients calculated from dark experiments are generally higher than those from the model fitting method for illumination experiments. Due to the correlation between k p 0 and z 0.5 in thinner layers, D eff should be estimated by an independent method for better accuracy. Despite some limitations of the model used in this study, the fitted parameters were useful for describing empirical results of photodegradation of soot-associated PAHs. - Highlights: ► PAHs on soot were evaluated by a model of coupled photolysis and diffusion. ► Photodegradation rate at the surface, diffusion coefficient, and light penetration path were determined. ► Low MW PAHs were influenced by fast photodegradation and fast diffusion. ► High MW PAHs were controlled either by slow

  10. Observational Evidence Linking Interstellar UV Absorption to PAH Molecules

    Energy Technology Data Exchange (ETDEWEB)

    Blasberger, Avi; Behar, Ehud; Perets, Hagai B. [Department of Physics, Technion (Israel); Brosch, Noah [The Wise Observatory and School of Physics and Astronomy, Tel Aviv University (Israel); Tielens, Alexander G. G. M. [Leiden Observatory, Leiden University (Netherlands)

    2017-02-20

    The 2175 Å UV extinction feature was discovered in the mid-1960s, yet its physical origin remains poorly understood. One suggestion is absorption by polycyclic aromatic hydrocarbon (PAH) molecules, which is supported by theoretical molecular structure computations and by laboratory experiments. PAHs are positively detected by their 3.3, 6.2, 7.7, 8.6, 11.3, and 12.7 μ m IR emission bands, which are specified by their modes of vibration. A definitive empirical link between the 2175 Å UV extinction and the IR PAH emission bands, however, is still missing. We present a new sample of hot stars that have both 2175 Å absorption and IR PAH emission. We find significant shifts of the central wavelength of the UV absorption feature, up to 2350 Å, but predominantly in stars that also have IR PAH emission. These UV shifts depend on stellar temperature in a fashion that is similar to the shifts of the 6.2 and 7.7 μ m IR PAH bands, that is, the features are increasingly more redshifted as the stellar temperature decreases, but only below ∼15 kK. Above 15 kK both UV and IR features retain their nominal values. Moreover, we find a suggestive correlation between the UV and IR shifts. We hypothesize that these similar dependences of both the UV and IR features on stellar temperature hint at a common origin of the two in PAH molecules and may establish the missing link between the UV and IR observations. We further suggest that the shifts depend on molecular size, and that the critical temperature of ∼15 kK above which no shifts are observed is related to the onset of UV-driven hot-star winds and their associated shocks.

  11. Observational Evidence Linking Interstellar UV Absorption to PAH Molecules

    International Nuclear Information System (INIS)

    Blasberger, Avi; Behar, Ehud; Perets, Hagai B.; Brosch, Noah; Tielens, Alexander G. G. M.

    2017-01-01

    The 2175 Å UV extinction feature was discovered in the mid-1960s, yet its physical origin remains poorly understood. One suggestion is absorption by polycyclic aromatic hydrocarbon (PAH) molecules, which is supported by theoretical molecular structure computations and by laboratory experiments. PAHs are positively detected by their 3.3, 6.2, 7.7, 8.6, 11.3, and 12.7 μ m IR emission bands, which are specified by their modes of vibration. A definitive empirical link between the 2175 Å UV extinction and the IR PAH emission bands, however, is still missing. We present a new sample of hot stars that have both 2175 Å absorption and IR PAH emission. We find significant shifts of the central wavelength of the UV absorption feature, up to 2350 Å, but predominantly in stars that also have IR PAH emission. These UV shifts depend on stellar temperature in a fashion that is similar to the shifts of the 6.2 and 7.7 μ m IR PAH bands, that is, the features are increasingly more redshifted as the stellar temperature decreases, but only below ∼15 kK. Above 15 kK both UV and IR features retain their nominal values. Moreover, we find a suggestive correlation between the UV and IR shifts. We hypothesize that these similar dependences of both the UV and IR features on stellar temperature hint at a common origin of the two in PAH molecules and may establish the missing link between the UV and IR observations. We further suggest that the shifts depend on molecular size, and that the critical temperature of ∼15 kK above which no shifts are observed is related to the onset of UV-driven hot-star winds and their associated shocks.

  12. Monitoring of polycyclic aromatic hydrocarbons (PAH) in food supplements containing botanicals and other ingredients on the Dutch market

    NARCIS (Netherlands)

    Martena, M.J.; Grutters, M.; Groot, de H.N.; Konings, E.J.M.; Rietjens, I.

    2011-01-01

    Food supplements can contain polycyclic aromatic hydrocarbons (PAH). The European Food Safety Authority (EFSA) has defined 16 priority PAH that are both genotoxic and carcinogenic and identified eight priority PAH (PAH8) or four of these (PAH4) as good indicators of the toxicity and occurrence of

  13. Biodegradation, bioaccessibility, and genotoxicity of diffuse polycyclic aromatic hydrocarbon (PAH) pollution at a motorway site

    DEFF Research Database (Denmark)

    Johnsen, A.R.; de Lipthay, J.R.; Reichenberg, F.

    2006-01-01

    the asphalt pavement and tested for total amounts of PAHs, amounts of bioaccessible PAHs, total bacterial populations, PAH degrader populations, the potential for mineralization of C-14-PAHs, and mutagenicity. Elevated PAH concentrations were found in the samples taken 1-8 m from the pavement. Soil sampled...... in the most polluted samples close to the pavement. Hydroxypropyl-beta-cyclodextrin extraction of soil PAHs, as a direct estimate of the bioaccessibility, indicated that only 1-5% of the PAHs were accessible to soil bacteria. This low bioaccessibility is suggested to be due to sorption to traffic soot...... particles. The increased PAH level close to the pavement was reflected in slightly increased mutagenic activity (1 m, 0.32 +/- 0.08 revertants g(-1) soil; background/24 m: 0.08 +/- 0.04), determined by the Salmonella/microsome assay of total extractable PAHs activated by liver enzymes. The potential...

  14. Distribution of polycyclic aromatic hydrocarbons (PAHs) in surface sediments of Pulau Tinggi, Johor

    Science.gov (United States)

    Razak, Ezzati Sulhi Abdul; Halim, Izzyan Syazwani Abdul; Ali, Masni Mohd

    2016-11-01

    Surface sediments samples were collected at 11 stations around the Pulau Tinggi, Johor in September 2015. A total of 15 PAHs were determined and quantified by gas chromatography coupled with mass spectrometry (GC-MS). The total PAH concentrations of surface sediments from Pulau Tinggi ranged from 39.61 ng/g to 149.2 ng/g and they were classified as being in low to moderate pollution range. Individual PAH analysis showed that two and three rings PAHs were the most frequently detected isomers and accounted for 22 - 46% of the total PAH concentrations. The sources of PAHs were evaluated by employing diagnostic ratiosof specific PAH compounds.PAH ratios analysis showed a prevalence of pyrogenic PAH origin at most of the stations with exception of only a few stations.

  15. Biodegradation, bioaccessibility, and genotoxicity of diffuse polycyclic aromatic hydrocarbon (PAH) pollution at a motorway site

    DEFF Research Database (Denmark)

    Johnsen, A.R.; de Lipthay, J.R.; Reichenberg, F.

    2006-01-01

    Diffuse pollution of surface soil with polycyclic aromatic hydrocarbons (PAHs) is problematic in terms of the large areas and volumes of polluted soil. The levels and effects of diffuse PAH pollution at a motorway site were investigated. Surface soil was sampled with increasing distance from...... in the most polluted samples close to the pavement. Hydroxypropyl-beta-cyclodextrin extraction of soil PAHs, as a direct estimate of the bioaccessibility, indicated that only 1-5% of the PAHs were accessible to soil bacteria. This low bioaccessibility is suggested to be due to sorption to traffic soot...... the asphalt pavement and tested for total amounts of PAHs, amounts of bioaccessible PAHs, total bacterial populations, PAH degrader populations, the potential for mineralization of C-14-PAHs, and mutagenicity. Elevated PAH concentrations were found in the samples taken 1-8 m from the pavement. Soil sampled...

  16. Does Excessive Pronation Cause Pain?

    DEFF Research Database (Denmark)

    Mølgaard, Carsten Møller; Olesen Gammelgaard, Christian; Nielsen, R. G.

    Excessive pronation could be an inborn abnormality or an acquired foot disorder caused by overuse, inadequate supported shoes or inadequate foot training. When the muscles and ligaments of the foot are insufficient it can cause an excessive pronation of the foot. The current treatment consist...... of antipronation shoes or insoles, which latest was studied by Kulce DG., et al (2007). So far there have been no randomized controlled studies showing methods that the effect of this treatment has not been documented. Therefore the authors can measure the effect of treatments with insoles. Some of the excessive...

  17. THE CHARGE STATE OF POLYCYCLIC AROMATIC HYDROCARBONS ACROSS REFLECTION NEBULAE: PAH CHARGE BALANCE AND CALIBRATION

    International Nuclear Information System (INIS)

    Boersma, C.; Bregman, J.; Allamandola, L. J.

    2016-01-01

    Low-resolution Spitzer spectral map data (>1700 spectra) of ten reflection nebulae (RNe) fields are analyzed using the data and tools available through the NASA Ames PAH IR Spectroscopic Database. The PAH emission is broken down into PAH charge state using a database fitting approach. Here, the physics of the PAH emission process is taken into account and uses target appropriate parameters, e.g., a stellar radiation model for the exciting star. The breakdown results are combined with results derived using the traditional PAH band strength approach, which interprets particular PAH band strength ratios as proxies for the PAH charge state, e.g., the 6.2/11.2 μ m PAH band strength ratio. These are successfully calibrated against their database equivalent; the PAH ionized fraction ( f i ). The PAH ionized fraction is converted into the PAH ionization parameter, which relates the PAH ionized fraction to the strength of the radiation field, gas temperature and electron density. The behavior of the 12.7 μ m PAH band is evaluated as a tracer for PAH ionization and erosion. The plot of the 8.6 versus 11.2 μ m PAH band strength for the northwest photo-dominated region (PDR) in NGC 7023 is shown to be a robust diagnostic template for the PAH ionized fraction. Remarkably, most of the other RNe fall within the limits set by NGC 7023. Finally, PAH spectroscopic templates are constructed and verified as principal components. Template spectra derived from NGC 7023 and NGC 2023 compare extremely well with each other, with those derived for NGC 7023 successfully reproducing the PAH emission observed from NGC 2023.

  18. THE CHARGE STATE OF POLYCYCLIC AROMATIC HYDROCARBONS ACROSS REFLECTION NEBULAE: PAH CHARGE BALANCE AND CALIBRATION

    Energy Technology Data Exchange (ETDEWEB)

    Boersma, C.; Bregman, J.; Allamandola, L. J., E-mail: Christiaan.Boersma@nasa.gov [NASA Ames Research Center, MS 245-6, Moffett Field, CA 94035-0001 (United States)

    2016-11-20

    Low-resolution Spitzer spectral map data (>1700 spectra) of ten reflection nebulae (RNe) fields are analyzed using the data and tools available through the NASA Ames PAH IR Spectroscopic Database. The PAH emission is broken down into PAH charge state using a database fitting approach. Here, the physics of the PAH emission process is taken into account and uses target appropriate parameters, e.g., a stellar radiation model for the exciting star. The breakdown results are combined with results derived using the traditional PAH band strength approach, which interprets particular PAH band strength ratios as proxies for the PAH charge state, e.g., the 6.2/11.2 μ m PAH band strength ratio. These are successfully calibrated against their database equivalent; the PAH ionized fraction ( f {sub i} ). The PAH ionized fraction is converted into the PAH ionization parameter, which relates the PAH ionized fraction to the strength of the radiation field, gas temperature and electron density. The behavior of the 12.7 μ m PAH band is evaluated as a tracer for PAH ionization and erosion. The plot of the 8.6 versus 11.2 μ m PAH band strength for the northwest photo-dominated region (PDR) in NGC 7023 is shown to be a robust diagnostic template for the PAH ionized fraction. Remarkably, most of the other RNe fall within the limits set by NGC 7023. Finally, PAH spectroscopic templates are constructed and verified as principal components. Template spectra derived from NGC 7023 and NGC 2023 compare extremely well with each other, with those derived for NGC 7023 successfully reproducing the PAH emission observed from NGC 2023.

  19. PAHs sensitivity of picophytoplankton populations in the Red Sea.

    Science.gov (United States)

    Kottuparambil, Sreejith; Agusti, Susana

    2018-04-25

    In this study, we investigated the in situ responses of Red Sea picophytoplankton, the dominant phytoplankton group in the oligotrophic ocean, to two toxic polycyclic aromatic hydrocarbons (PAHs), phenanthrene and pyrene. The experiments were conducted across a latitudinal gradient of the Saudi Arabian Red Sea, an area sensitive to oil pollution. We observed significant adverse effects on the growth and abundance of the picocyanobacteria Synechococcus and picoeukaryotes, at all stations sampled. Prochlorococcus, which was abundant only at one of the stations, also appeared to be affected. Pyrene was found to be more toxic to phytoplankton at all stations. In general, picoeukaryotes exhibited higher sensitivity to PAHs than Synechococcus. Populations in the highly oligotrophic Northern region of the Red Sea were more tolerant to PAHs, presumably influenced by the natural selection of more resistant strains of phytoplankton due to the prolonged exposure to PAHs. Toxicity threshold values estimated here are higher than those reported for picophytoplankton from other oligotrophic marine waters and exceed by far the natural levels of PAHs in many oceans. Our findings reveal a possible adaptation of picophytoplankton populations to oil-related contaminants, which may clearly influence their spatial distribution patterns in the Red Sea. Copyright © 2018 Elsevier Ltd. All rights reserved.

  20. PAHs soil decontamination in two steps: desorption and electrochemical treatment.

    Science.gov (United States)

    Alcántara, M Teresa; Gómez, Jose; Pazos, Marta; Sanromán, M Angeles

    2009-07-15

    The presence of carcinogenic polycyclic aromatic hydrocarbons (PAHs) in soils poses a potential threat to human health if exposure levels are too high. Nevertheless, the removal of these contaminants presents a challenge to scientists and engineers. The high hydrophobic nature of PAHs enables their strong sorption onto soil or sediments. Thus, the use of surfactants could favour the release of sorbed hydrophobic organic compounds from contaminated soils. In this work, five surfactants, namely Brij 35, Tergitol NP10, Tween 20, Tween 80 and Tyloxapol, are evaluated on the desorption of PAHs [benzanthracene (BzA), fluoranthene (FLU), and pyrene (PYR), single and in mixture] from a model sample such as kaolin. In all cases, the best results were obtained when Tween 80 was employed. In order to obtain the global decontamination of PAHs, their electrochemical degradation is investigated. It is concluded that the order of increasing degradation for single compounds is BzA>FLU>PYR when they are subject to the same electrochemical treatment. In addition, there is a direct relationship between the ionization potential and the electrochemical degradation of PAH.

  1. Indoor PAHs at schools, homes and offices in Rome, Italy

    Science.gov (United States)

    Romagnoli, P.; Balducci, C.; Perilli, M.; Gherardi, M.; Gordiani, A.; Gariazzo, C.; Gatto, M. P.; Cecinato, A.

    2014-08-01

    Indoor and outdoor concentrations of polycyclic aromatic hydrocarbons (PAHs) associated with PM2.5 particles were monitored in three microenvironments (schools, homes and offices) in the city of Rome, Italy, between winter 2011 and summer 2012. Molecular signatures and indoor/outdoor concentration ratios of PAHs were investigated, with special emphasis on carcinogenic congeners. At indoor locations, total PAHs ranged, on average, from 1.8 to 8.4 ng/m3 in winter and from 0.30 to 1.35 ng/m3 in spring/summer. Outdoors, total PAH concentrations were found to reach 6.3-17.9 ng/m3 in winter and 0.42-1.74 ng/m3 in spring-summer. Indoors, the concentration of benzo[a]pyrene (BaP) was as high as 1.1 ng/m3 in winter and below 0.1 ng/m3 in the warm season, independently of site type; the yearly average remained below the European guideline value. The indoor/outdoor concentration ratios of individual compounds were lower than one for most of congeners, suggesting that outdoor sources were predominant. Nonetheless, the percentages of PAH compounds changed with sites and seasons; in particular, in spring/summer, the concentration of BaP at our sites was more than twice that recorded at the regional network stations.

  2. The formation of aromatics and PAH's in laminar flames

    International Nuclear Information System (INIS)

    Marinov, N M; Pitz, W J; Westbrook, C K

    1999-01-01

    The formation of aromatics and PAH's is an important problem in combustion. These compounds are believed to contribute to the formation of soot whose emission from diesel engines is regulated widely throughout the industrial world. Additionally, the United States Environmental Protection Agency regulates the emission of many aromatics and PAH species from stationary industrial burners, under the 1990 Clean Air Act Amendments. The above emission regulations have created much interest in understanding how these species are formed in combustion systems. Much previous work has been done on aromatics and PAH's. The work is too extensive to review here, but is reviewed in Reference 1. A few recent developments are highlighted here. McEnally, Pfefferle and coworkers have studied aromatic, PAH and soot formation in a variety of non-premixed flames with hydrocarbon additives[2-4]. They found additives that contain a C5 ring increase the concentration of aromatics and soot[4]. Howard and coworkers have studied the formation of aromatic and PAH's in low pressure, premixed, laminar hydrocarbon flames. They found the cyclopentadienyl radical to be a key species in naphthalene formation in a fuel-rich, benzene/Ar/O2 flame[5

  3. PAHs sensitivity of picophytoplankton populations in the Red Sea

    KAUST Repository

    Kottuparambil, Sreejith

    2018-04-25

    In this study, we investigated the in situ responses of Red Sea picophytoplankton, the dominant phytoplankton group in the oligotrophic ocean, to two toxic polycyclic aromatic hydrocarbons (PAHs), phenanthrene and pyrene. The experiments were conducted across a latitudinal gradient of the Saudi Arabian Red Sea, an area sensitive to oil pollution. We observed significant adverse effects on the growth and abundance of the picocyanobacteria Synechococcus and picoeukaryotes, at all stations sampled. Prochlorococcus, which was abundant only at one of the stations, also appeared to be affected. Pyrene was found to be more toxic to phytoplankton at all stations. In general, picoeukaryotes exhibited higher sensitivity to PAHs than Synechococcus. Populations in the highly oligotrophic Northern region of the Red Sea were more tolerant to PAHs, presumably influenced by the natural selection of more resistant strains of phytoplankton due to the prolonged exposure to PAHs. Toxicity threshold values estimated here are higher than those reported for picophytoplankton from other oligotrophic marine waters and exceed by far the natural levels of PAHs in many oceans. Our findings reveal a possible adaptation of picophytoplankton populations to oil-related contaminants, which may clearly influence their spatial distribution patterns in the Red Sea.

  4. STAR FORMATION RATES FOR STARBURST GALAXIES FROM ULTRAVIOLET, INFRARED, AND RADIO LUMINOSITIES

    International Nuclear Information System (INIS)

    Sargsyan, Lusine A.; Weedman, Daniel W.

    2009-01-01

    We present a comparison of star formation rates (SFR) determined from mid-infrared 7.7 μm polycyclic aromatic hydrocarbon (PAH) luminosity [SFR(PAH)], from 1.4 GHz radio luminosity [SFR(radio)], and from far-ultraviolet luminosity [SFR(UV)] for a sample of 287 starburst galaxies with z ν (7.7 μm)] - 42.57 ± 0.2, for SFR in M sun yr -1 and νL ν (7.7 μm) the luminosity at the peak of the 7.7 μm PAH feature in erg s -1 , is found to agree with SFR(radio). Comparing with SFR(UV) determined independently from ultraviolet observations of the same sources with the Galaxy Evolution Explorer mission (not corrected for dust extinction), the median log [SFR(PAH)/SFR(UV)] = 1.67, indicating that only 2% of the ultraviolet continuum typically escapes extinction by dust within a starburst. This ratio SFR(PAH)/SFR(UV) depends on infrared luminosity, with the form log [SFR(PAH)/SFR(UV)] = (0.53 ± 0.05)log [νL ν (7.7 μm)] - 21.5 ± 0.18, indicating that more luminous starbursts are also dustier. Using our adopted relation between νL ν (7.7 μm) and L ir , this becomes log [SFR(PAH)/SFR(UV)]= (0.53 ± 0.05)log L ir - 4.11 ± 0.18, for L ir in L sun . Only blue compact dwarf galaxies show comparable or greater SFR(UV) compared to SFR(PAH). We also find that the ratio SFR(PAH)/SFR(UV) is similar to that in infrared-selected starbursts for a sample of Markarian starburst galaxies originally selected using optical classification, which implies that there is no significant selection effect in SFR(PAH)/SFR(UV) using starburst galaxies discovered by Spitzer. These results indicate that SFRs determined with ultraviolet luminosities require dust corrections by a factor of ∼10 for typical local starbursts but this factor increases to >700 for the most luminous starbursts at z ∼ 2.5. Application of this factor explains why the most luminous starbursts discovered by Spitzer at z ∼ 2.5 are optically faint; with this amount of extinction, the optical magnitude of a starburst

  5. Variations of emission characterization of PAHs emitted from different utility boilers of coal-fired power plants and risk assessment related to atmospheric PAHs

    International Nuclear Information System (INIS)

    Wang, Ruwei; Liu, Guijian; Zhang, Jiamei

    2015-01-01

    Coal-fired power plants (CFPPs) represent important source of atmospheric PAHs, however, their emission characterization are still largely unknown. In this work, the concentration, distribution and gas-particle partitioning of PM_1_0- and gas-phase PAHs in flue gas emitted from different coal-fired utility boilers were investigated. Moreover, concentration and distribution in airborne PAHs from different functional areas of power plants were studied. People's inhalatory and dermal exposures to airborne PAHs at these sites were estimated and their resultant lung cancer and skin cancer risks were assessed. Results indicated that the boiler capacity and operation conditions have significant effect on PAH concentrations in both PM_1_0 and gas phases due to the variation of combustion efficiency, whereas they take neglected effect on PAH distributions. The wet flue gas desulphurization (WFGD) takes significant effect on the scavenging of PAH in both PM_1_0 and gas phases, higher scavenging efficiency were found for less volatile PAHs. PAH partitioning is dominated by absorption into organic matter and accompanied by adsorption onto PM_1_0 surface. In addition, different partitioning mechanism is observed for individual PAHs, which is assumed arising from their chemical affinity and vapor pressure. Risk assessment indicates that both inhalation and dermal contact greatly contribute to the cancer risk for CFPP workers and nearby residents. People working in workshop are exposed to greater inhalation and dermal exposure risk than people living in nearby vicinity and working office. - Highlights: • PAH distribution in PM_1_0 and gas phases primarily depend on the vapor pressure. • Combustion conditions and WFGD show typical effects on PAH level and profile. • PAH partitioning is dominated by absorption and also accompanied by adsorption. • Individual PAHs show different partitioning mechanisms in PM_1_0- and gas-phases. • People in workshop suffer greater cancer

  6. Variations of emission characterization of PAHs emitted from different utility boilers of coal-fired power plants and risk assessment related to atmospheric PAHs

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ruwei [CAS Key Laboratory of Crust-Mantle and the Environment, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui (China); State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, The Chinese Academy of Sciences, Xi' an 710075, Shanxi (China); Liu, Guijian, E-mail: lgj@ustc.edu.cn [CAS Key Laboratory of Crust-Mantle and the Environment, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui (China); State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, The Chinese Academy of Sciences, Xi' an 710075, Shanxi (China); Zhang, Jiamei [CAS Key Laboratory of Crust-Mantle and the Environment, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui (China)

    2015-12-15

    Coal-fired power plants (CFPPs) represent important source of atmospheric PAHs, however, their emission characterization are still largely unknown. In this work, the concentration, distribution and gas-particle partitioning of PM{sub 10}- and gas-phase PAHs in flue gas emitted from different coal-fired utility boilers were investigated. Moreover, concentration and distribution in airborne PAHs from different functional areas of power plants were studied. People's inhalatory and dermal exposures to airborne PAHs at these sites were estimated and their resultant lung cancer and skin cancer risks were assessed. Results indicated that the boiler capacity and operation conditions have significant effect on PAH concentrations in both PM{sub 10} and gas phases due to the variation of combustion efficiency, whereas they take neglected effect on PAH distributions. The wet flue gas desulphurization (WFGD) takes significant effect on the scavenging of PAH in both PM{sub 10} and gas phases, higher scavenging efficiency were found for less volatile PAHs. PAH partitioning is dominated by absorption into organic matter and accompanied by adsorption onto PM{sub 10} surface. In addition, different partitioning mechanism is observed for individual PAHs, which is assumed arising from their chemical affinity and vapor pressure. Risk assessment indicates that both inhalation and dermal contact greatly contribute to the cancer risk for CFPP workers and nearby residents. People working in workshop are exposed to greater inhalation and dermal exposure risk than people living in nearby vicinity and working office. - Highlights: • PAH distribution in PM{sub 10} and gas phases primarily depend on the vapor pressure. • Combustion conditions and WFGD show typical effects on PAH level and profile. • PAH partitioning is dominated by absorption and also accompanied by adsorption. • Individual PAHs show different partitioning mechanisms in PM{sub 10}- and gas-phases. • People in

  7. Near-infrared proper motions and spectroscopy of infrared excess sources at the Galactic center

    Czech Academy of Sciences Publication Activity Database

    Eckart, A.; Muzic, K.; Yazici, S.; Sabha, N.; Shahzamanian, B.; Witzel, G.; Moser, L.; García-Marín, M.; Valencia-S, M.; Jalali, B.; Bremer, M.; Straubmeier, C.; Rauch, C.; Buchholz, R. M.; Kunneriath, Devaky; Moultaka, J.

    2013-01-01

    Roč. 551, March (2013), A18/1-A18/31 ISSN 0004-6361 Grant - others:ESA(XE) ESA- PECS projec No. 98040; DFG(DE) SFB 956; EU(XE) COST Action MP0905; BMBF(DE) 50OS1101 Institutional support: RVO:67985815 Keywords : galaxy center * early-type stars Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.479, year: 2013

  8. Dermal tumorigen PAH and complex mixtures for biological research

    International Nuclear Information System (INIS)

    Griest, W.H.; Guerin, M.R.; Ho, C.

    1985-01-01

    Thirteen commercially available, commonly reported four-five ring dermal tumorigen PAHs, were determined in a set of complex mixtures consisting of crude and upgraded coal liquids, and petroleum crude oils and their distillate fractions. Semi-preparative scale, normal phase high performance liquid chromatographic fractionation followed by capillary column gas chromatography or gas chromatography-mass spectroscopy were used for the measurements. Deuterated or carbon-14 labeled PAH served as internal standards or allowed recovery corrections. Approaches for the preparation and measurement of radiolabeled PAH were examined to provide chemical probes for biological study. Synthetic routes for production of 14 C labeled dihydrobenzo[a]pyrene and 14 C- or 3 H 10-azabenzo[a]pyrene are being studied to provide tracers for fundamental studies in tracheal transplant and skin penetration systems. (DT)

  9. PAHs in corn grains submitted to drying with firewood.

    Science.gov (United States)

    de Lima, Rafael Friedrich; Dionello, Rafael Gomes; Peralba, Maria do Carmo Ruaro; Barrionuevo, Simone; Radunz, Lauri Lourenço; Reichert Júnior, Francisco Wilson

    2017-01-15

    Grain drying using firewood as fuel for air heating, with direct fire, is still widely used in Brazil. The combustion of organic material, such as wood, can generate polycyclic aromatic hydrocarbons (PAHs) which are known to have carcinogenic potential. In the present work corn grain drying was carried out at three drying air temperatures: 60°C, 60/80°C and 80°C. Following the drying process, the presence and quantification of PAH in the corn grains was investigated. After extracting the PAHs of the matrix, the material was subjected to analysis by gas chromatography with mass detector. he results showed the presence of seven compounds: fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo(a)anthracene and chrysene. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Intestinal metabolism of PAH: in vitro demonstration and study of its impact on PAH transfer through the intestinal epithelium

    International Nuclear Information System (INIS)

    Cavret, Severine; Feidt, Cyril

    2005-01-01

    Food would seem to be one of the main ways of animal and human contamination with polycyclic aromatic hydrocarbons (PAHs). In vivo studies suggest a transfer in intestinal epithelium by diffusion, which appears extensively governed by the physicochemical properties of PAHs, particularly lipophilicity. However, other mechanisms, such as metabolism, are considered to intervene. Our work aimed at testing in vitro intestinal metabolism and defining its impact on transepithelial transport of PAHs. Caco-2 cells were cultivated on permeable filters and incubated with 14 C-labeled benzo[a]pyrene (BaP), pyrene (Pyr), and phenanthrene (Phe), which differ in their physicochemical properties. The results showed that the cells were able to metabolize the compounds. In basal media, Phe appeared to be the least hydroxylated molecule (45% after a 6-h exposure), followed by Pyr (65%) and finally BaP (96%). Inhibition of PAH metabolism showed a determinant effect on kinetics profiles. Transfer in the basal compartment of BaP, Pyr, and Phe radioactivities was, respectively, 26, 4, and 2 times lower with inhibitors, corroborating that intestinal metabolism of PAHs would have a positive impact on their transfer, an impact that increased with their lipophilicity. Furthermore, after a 6-h incubation, metabolites were also detected in apical medium. These findings suggested that intestinal metabolism might play a key role in intestinal barrier permeability and thus in the bioavailability of tested micropollutants

  11. Evaluation of bio-remediation technologies for PAHs contaminated soils

    International Nuclear Information System (INIS)

    Garcia Frutos, F.J.; Diaz, J.; Rodriguez, V.; Escolano, O.; Garcia, S.; Perez, R.; Martinez, R.; Oromendia, R.

    2005-01-01

    Natural attenuation is a new concept related to polluted soil remediation. Can be understood like an 'in situ' bio-remediation process with low technical intervention. This low intervention may be in order to follow the behaviour of pollutants 'monitored natural attenuation' or include an optimisation process to improve biological remediation. The use of this technology is a fact for light hydrocarbon polluted soil, but few is known about the behaviour of polycyclic aromatic hydrocarbons (PAHs) in this process. PAHs are more recalcitrant to bio-remediation due to their physic-chemical characteristics, mainly hydrophobicity and electrochemical stability. PAHs are a kind of pollutants widely distributed in the environment, not only in the proximity of the source. This linked to the characteristics of some of them related to toxicity and mutagenicity implies its inclusion as target compounds from an environmental point of view. Their low availability, solubility and the strong tendency to bind to soil particle, especially to the organic phase affect PAHs biological mineralisation. So, if the pollutant is not available to microorganisms it can not be bio-degraded. Bioavailability can be assessed form several but complementary points of view: physico-chemical and biological. First including the term availability and the second to point out the capacity of soil microorganisms to mineralize PAHs. Availability and Bio-degradability must be determined, as well as the presence and activity of specific degraders among the soil organisms, once settled these points is necessary to study the biological requirements to optimise biodegradation kinetics of these compounds. In this work we present a study carried out on a soil, contaminated by PAHs, the study includes three main topics: bioavailability assessment (both term availability and bio-degradability), bio-remediation assessment, once optimised conditions for natural attenuation and finally a simulation of the

  12. 24 CFR 236.60 - Excess Income.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Excess Income. 236.60 Section 236... § 236.60 Excess Income. (a) Definition. Excess Income consists of cash collected as rent from the... Rent. The unit-by-unit requirement necessitates that, if a unit has Excess Income, the Excess Income...

  13. Strong Impact on the Polycyclic Aromatic Hydrocarbon (PAH)-Degrading Community of a PAH-Polluted Soil but Marginal Effect on PAH Degradation when Priming with Bioremediated Soil Dominated by Mycobacteria

    DEFF Research Database (Denmark)

    Johnsen, Anders R.; Schmidt, Stine; Hybholdt, Trine K.

    2007-01-01

    Bioaugmentation of soil polluted with polycyclic aromatic hydrocarbons (PAHs) is often disappointing because of the low survival rate and low activity of the introduced degrader bacteria. We therefore investigated the possibility of priming PAH degradation in soil by adding 2% of bioremediated soil...... with a high capacity for PAH degradation. The culturable PAH-degrading community of the bioremediated primer soil was dominated by Mycobacterium spp. A microcosm containing pristine soil artificially polluted with PAHs and primed with bioremediated soil showed a fast, 100- to 1,000-fold increase in numbers...... of culturable phenanthrene-, pyrene-, and fluoranthene degraders and a 160-fold increase in copy numbers of the mycobacterial PAH dioxygenase gene pdo1. A nonpolluted microcosm primed with bioremediated soil showed a high rate of survival of the introduced degrader community during the 112 days of incubation...

  14. Coal-tar pavement sealants might substantially increase children's PAH exposures

    Science.gov (United States)

    Williams, E. Spencer; Mahler, Barbara J.; Van Metre, Peter C.

    2012-01-01

    Dietary ingestion has been identified repeatedly as the primary route of human exposure to polycyclic aromatic hydrocarbons (PAHs), seven of which are classified as probable human carcinogens (B2 PAHs) by the U.S. EPA. Humans are exposed to PAHs through ingestion of cooked and uncooked foods, incidental ingestion of soil and dust, inhalation of ambient air, and absorption through skin. Although PAH sources are ubiquitous in the environment, one recently identified PAH source stands out: Coal-tar-based pavement sealant—a product applied to many parking lots, driveways, and even playgrounds primarily in the central, southern, and eastern U.S.—has PAH concentrations 100–1000 times greater than most other PAH sources. It was reported recently that PAH concentrations in house dust in residences adjacent to parking lots with coal-tar-based sealant were 25 times higher than in residences adjacent to unsealed asphalt parking lots.

  15. PAH growth initiated by propargyl addition: Mechanism development and computational kinetics

    KAUST Repository

    Raj, Abhijeet Dhayal; Rachidi, Mariam El; Chung, Suk-Ho; Sarathy, Mani

    2014-01-01

    Polycyclic aromatic hydrocarbon (PAH) growth is known to be the principal pathway to soot formation during fuel combustion, as such, a physical understanding of the PAH growth mechanism is needed to effectively assess, predict, and control soot

  16. Biological risk and pollution history of polycyclic aromatic hydrocarbons (PAHs) in Nansha mangrove, South China.

    Science.gov (United States)

    Wu, Qihang; Leung, Jonathan Y S; Tam, Nora F Y; Chen, Shejun; Mai, Bixian; Zhou, Xizhen; Xia, Lihua; Geng, Xinhua

    2014-08-15

    Chinese government has taken various measures to alleviate pollution caused by polycyclic aromatic hydrocarbons (PAHs) in the region of Pearl River Delta since the economic reform in 1978, but the effectiveness of these measures remains largely unknown. This study aimed to elucidate the biological risk and pollution history of PAHs by measuring the concentrations of 28 PAHs in the surface and core sediments, respectively, in Nansha mangrove. Results found that the biological risk of PAHs was low without obvious spatial variation. The PAH concentration along the depth gradient indicated that PAH pollution was stabilized since the early 1990s while the source of PAHs has gradually changed from combustion of coal to petroleum products. This implied that the mitigation measures taken by the Chinese government were effective. Compared to marine bottom sediment, we propose that using mangrove sediment can provide a more accurate and precise estimate of pollution history of PAHs. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Structural dynamics of PAH molecules upon energetic photon or ion interactions

    NARCIS (Netherlands)

    Reitsma, Geert

    2014-01-01

    Polycyclische aromatische koolwaterstoffen (PAHs) vormen een hele bijzondere familie van moleculen. PAHs bestaan uit ringen van koolstofatomen en hebben waterstofatomen op de randen. Zo ontstaan platte en heel erg stabiele moleculen. Deze moleculen komen overal voor, bijvoorbeeld in uitlaatgassen en

  18. Multispecies and monoculture rhizoremediation of polycyclic aromatic hydrocarbons (PAHs) from the soil

    CSIR Research Space (South Africa)

    Maila, MP

    2005-01-01

    Full Text Available In this study, the authors investigated the potential of multispecies rhizoremediation and monoculture rhizoremediation in decontaminating polycyclic aromatic hydrocarbon (PAH) contaminated soil. Plant-mediated PAH dissipation was evaluated using...

  19. Impact of soil amendments and the plant rhizosphere on PAH behaviour in soil

    DEFF Research Database (Denmark)

    Marchal, Geoffrey; Smith, Kilian E.C.; Mayer, Philipp

    2014-01-01

    Carbonaceous amendments reduce PAH dissolved concentrations (Cfree), limiting their uptake and toxicity. A soil contaminated with PAHs was mixed with activated carbon (AC), charcoal or compost and planted with radish (Raphanus sativus L.), and Cfree, chemical activities and diffusive uptake...

  20. Splicing of phenylalanine hydroxylase (PAH) exon 11 is vulnerable - Molecular pathology of mutations in PAH exon 11

    DEFF Research Database (Denmark)

    Heintz, Caroline; Dobrowolski, Steven F.; Andersen, Henriette Skovgaard

    2012-01-01

    as a vulnerable exon and used patient derived lymphoblast cell lines and PAH minigenes to study the molecular defect that impacted pre-mRNA processing. We showed that the c.1144T>C and c.1066-3C>T mutations cause exon 11 skipping, while the c.1139C>T mutation is neutral or slightly beneficial. The c.1144T......In about 20-30% of phenylketonuria (PKU) patients, phenylalanine (Phe) levels can be controlled by cofactor 6R-tetrahydrobiopterin (BH(4)) administration. The phenylalanine hydroxylase (PAH) genotype has a predictive value concerning BH(4)-response and therefore a correct assessment of the mutation...... molecular pathology is important. Mutations that disturb the splicing of exons (e.g. interplay between splice site strength and regulatory sequences like exon splicing enhancers (ESEs)/exon splicing silencers (ESSs)) may cause different severity of PKU. In this study, we identified PAH exon 11...

  1. Quantification of PAHs and oxy-PAHs on airborne particulate matter in Chiang Mai, Thailand, using gas chromatography high resolution mass spectrometry

    Science.gov (United States)

    Walgraeve, Christophe; Chantara, Somporn; Sopajaree, Khajornsak; De Wispelaere, Patrick; Demeestere, Kristof; Van Langenhove, Herman

    2015-04-01

    An analytical method using gas chromatography high resolution mass spectrometry was developed for the determination of 16 polycyclic aromatic hydrocarbons (PAHs) and 12 oxygenated PAHs (of which 4 diketones, 3 ketones, 4 aldehydes and one anhydride) on atmospheric particulate matter with an aerodynamic diameter less than 10 μm (PM10). The magnetic sector mass spectrometer was run in multiple ion detection mode (MID) with a mass resolution above 10 000 (10% valley definition) and allows for a selective accurate mass detection of the characteristic ions of the target analytes. Instrumental detection limits between 0.04 pg and 1.34 pg were obtained for the PAHs, whereas for the oxy-PAHs they ranged between 0.08 pg and 2.13 pg. Pressurized liquid extraction using dichloromethane was evaluated and excellent recoveries ranging between 87% and 98% for the PAHs and between 74% and 110% for 10 oxy-PAHs were obtained, when the optimum extraction temperature of 150 °C was applied. The developed method was finally used to determine PAHs and oxy-PAHs concentration levels from particulate matter samples collected in the wet season at 4 different locations in Chiang Mai, Thailand (n = 72). This study brings forward the first concentration levels of oxy-PAHs in Thailand. The median of the sum of the PAHs and oxy-PAHs concentrations was 3.4 ng/m3 and 1.1 ng/m3 respectively, which shows the importance of the group of the oxy-PAHs as PM10 constituents. High molecular weight PAHs contributed the most to the ∑PAHs. For example, benzo[ghi]perylene was responsible for 30-44% of the ∑PAHs. The highest contribution to ∑oxy-PAHs came from 1,8-napthalic anhydride (26-78%), followed by anthracene-9,10-dione (4-27%) and 7H-benzo[de]anthracene-7-one (6-26%). Indications of the degradation of PAHs and/or formation of oxy-PAHs were observed.

  2. Variations of emission characterization of PAHs emitted from different utility boilers of coal-fired power plants and risk assessment related to atmospheric PAHs.

    Science.gov (United States)

    Wang, Ruwei; Liu, Guijian; Zhang, Jiamei

    2015-12-15

    Coal-fired power plants (CFPPs) represent important source of atmospheric PAHs, however, their emission characterization are still largely unknown. In this work, the concentration, distribution and gas-particle partitioning of PM10- and gas-phase PAHs in flue gas emitted from different coal-fired utility boilers were investigated. Moreover, concentration and distribution in airborne PAHs from different functional areas of power plants were studied. People's inhalatory and dermal exposures to airborne PAHs at these sites were estimated and their resultant lung cancer and skin cancer risks were assessed. Results indicated that the boiler capacity and operation conditions have significant effect on PAH concentrations in both PM10 and gas phases due to the variation of combustion efficiency, whereas they take neglected effect on PAH distributions. The wet flue gas desulphurization (WFGD) takes significant effect on the scavenging of PAH in both PM10 and gas phases, higher scavenging efficiency were found for less volatile PAHs. PAH partitioning is dominated by absorption into organic matter and accompanied by adsorption onto PM10 surface. In addition, different partitioning mechanism is observed for individual PAHs, which is assumed arising from their chemical affinity and vapor pressure. Risk assessment indicates that both inhalation and dermal contact greatly contribute to the cancer risk for CFPP workers and nearby residents. People working in workshop are exposed to greater inhalation and dermal exposure risk than people living in nearby vicinity and working office. Copyright © 2015. Published by Elsevier B.V.

  3. Excessive or unwanted hair in women

    Science.gov (United States)

    Hypertrichosis; Hirsutism; Hair - excessive (women); Excessive hair in women; Hair - women - excessive or unwanted ... Women normally produce low levels of male hormones (androgens). If your body makes too much of this ...

  4. PAH in Barbecued Meat from Restaurants and by Home-Grilling in Denmark

    DEFF Research Database (Denmark)

    Duedahl-Olesen, Lene; Meinert, L.; Aaslyng, M.

    2011-01-01

    Barbecuing or grilling is known to result in the formation of polycyclic aromatic hydrocarbons (PAH). Thirty home-grilled meat samples (beef, pork and chicken) and 86 commercial grilled meat samples (beef, pork, chicken, salmon, lamb and calf) were analyzed for 23 PAH including PAH 4 (benzo[a]pyr...

  5. Relation between PAH and black carbon contents in size fractions of Norwegian harbor sediments

    International Nuclear Information System (INIS)

    Oen, Amy M.P.; Cornelissen, Gerard; Breedveld, Gijs D.

    2006-01-01

    Distributions of total organic carbon (TOC), black carbon (BC), and polycyclic aromatic hydrocarbons (PAH) were investigated in different particle size fractions for four Norwegian harbor sediments. The total PAH (16-EPA) concentrations ranged from 2 to 113 mg/kg dry weight with the greatest fraction of PAH mass in the sand fraction for three of the four sediments. TOC contents ranged from 0.84% to 14.2% and BC contents from 0.085% to 1.7%. This corresponds to organic carbon (OC = TOC - BC) contents in the range of 0.81-14% and BC:TOC ratios of 1.3-18.1%. PAH isomer ratios suggested that the PAH in all four sediments were of pyrogenic origin. Furthermore, stronger correlations between PAH versus BC (r 2 = 0.85) than versus OC (r 2 = 0.15) were found. For all size fractions and bulk sediments, the PAH-to-BC ratios for the total PAHs were on average 6 ± 3 mg PAH/g BC. These results suggest that PAH distributions were dominated by the presence of BC, rather than OC. As sorption to BC is much stronger than sorption to OC, this may result in significantly lower dissolved concentrations of PAH than expected on the basis of organic carbon partitioning alone. - PAH contents correlated better with black carbon than organic carbon for four Norwegian harbor sediments

  6. Enrichment behavior and transport mechanism of soil-bound PAHs during rainfall-runoff events

    International Nuclear Information System (INIS)

    Zheng Yi; Luo Xiaolin; Zhang Wei; Wu Bin; Han Feng; Lin Zhongrong; Wang Xuejun

    2012-01-01

    Polycyclic Aromatic Hydrocarbons (PAHs) transported by surface runoff result in nonpoint source pollution and jeopardize aquatic ecosystems. The transport mechanism of PAHs during rainfall-runoff events has been rarely studied regarding pervious areas. An experimental system was setup to simulate the runoff pollution process on PAHs-contaminated soil. The enrichment behavior of soil-bound PAHs was investigated. The results show that soil organic matters (SOM), rather than clay particles, seem to be the main carrier of PAHs. The enrichment is highly conditioned on runoff and erosion processes, and its magnitude varies among PAH compounds. It is not feasible to build a simple and universal relationship between enrichment ratio and sediment discharge following the traditional enrichment theory. To estimate the flux of PAHs from pervious areas, soil erosion process has to be clearly understood, and both organic carbon content and composition of SOM should be factored into the calculation. - Highlights: ► Significant enrichment of particle-bound PAHs during rainfall-runoff events. ► Organic matters as the direct carrier of PAHs in runoff from contaminated soil. ► The traditional enrichment theory is not fully valid for PAHs. - The traditional enrichment theory is not fully valid for PAHs, and soil organic matters have a significant impact on the transport of PAHs during rainfall-runoff events.

  7. 75 FR 8937 - Development of a Relative Potency Factor (RPF) Approach for Polycyclic Aromatic Hydrocarbon (PAH...

    Science.gov (United States)

    2010-02-26

    ... Relative Potency Factor (RPF) Approach for Polycyclic Aromatic Hydrocarbon (PAH) Mixtures AGENCY... Aromatic Hydrocarbon (PAH) Mixtures'' (EPA/635/R-08/012A). The draft document was prepared by the National... 27, 2010. The listening session on the draft document for PAH mixtures will be held on April 7, 2010...

  8. Polycyclic aromatic hydrocarbons (PAH) formation from the pyrolysis of different municipal solid waste fractions

    International Nuclear Information System (INIS)

    Zhou, Hui; Wu, Chunfei; Onwudili, Jude A.; Meng, Aihong; Zhang, Yanguo; Williams, Paul T.

    2015-01-01

    Highlights: • PAH from pyrolysis of 9 MSW fractions was investigated. • Pyrolysis of plastics released more PAH than that of biomass. • Naphthalene was the most abundant PAH in the tar. • The mechanism of PAH release from biomass and plastics was proposed. - Abstract: The formation of 2–4 ring polycyclic aromatic hydrocarbons (PAH) from the pyrolysis of nine different municipal solid waste fractions (xylan, cellulose, lignin, pectin, starch, polyethylene (PE), polystyrene (PS), polyvinyl chloride (PVC), and polyethylene terephthalate (PET)) were investigated in a fixed bed furnace at 800 °C. The mass distribution of pyrolysis was also reported. The results showed that PS generated the most total PAH, followed by PVC, PET, and lignin. More PAH were detected from the pyrolysis of plastics than the pyrolysis of biomass. In the biomass group, lignin generated more PAH than others. Naphthalene was the most abundant PAH, and the amount of 1-methynaphthalene and 2-methynaphthalene was also notable. Phenanthrene and fluorene were the most abundant 3-ring PAH, while benzo[a]anthracene and chrysene were notable in the tar of PS, PVC, and PET. 2-ring PAH dominated all tar samples, and varied from 40 wt.% to 70 wt.%. For PS, PET and lignin, PAH may be generated directly from the aromatic structure of the feedstock

  9. Comparative effects of several cyclodextrins on the extraction of PAHs from an aged contaminated soil

    International Nuclear Information System (INIS)

    Sánchez-Trujillo, M.A.; Morillo, E.; Villaverde, J.; Lacorte, S.

    2013-01-01

    The objective of the present study was to characterise the polycyclic aromatic hydrocarbons (PAHs) content of an aged contaminated soil and to propose remediation techniques using cyclodextrins (CDs). Four CDs solutions were tested as soil decontamination tool and proved more efficient in extracting PAHs than when an aqueous solution was used; especially two chemically modified CDs resulted in higher extraction percentages than natural β-CD. The highest extraction percentages were obtained for 3-ring PAHs, because of the appropriate size and shape of these compounds relative to those of the hydrophobic cavities of the CDs studied. A detailed mechanistic interpretation of the chemical modification of CDs on the extraction of the different PAHs has been performed, and connected with the role that the different hydrophobicities of the PAHs play in the extraction behaviour observed for the 16 PAHs, limiting their accessibility and the remaining risk of those PAHs not extractable by CDs. -- Highlights: ► Four cyclodextrins (CDs) solutions were tested as soil decontamination tool for PAHs. ► Extractions with CDs were higher than with electrolyte, especially with synthetic CDs. ► Extraction capacity depends on the adequate size of PAHs and CDs hydrophobic cavity. ► 2–3 ring PAHs, the more abundant in the soil, were extracted in higher percentages. ► CDs extract preferably the less hydrophobic and more potentially toxic PAHs. -- Cyclodextrin solutions are useful and interesting tools for the decontamination of soils polluted by PAHs

  10. Polycyclic aromatic hydrocarbons (PAH) formation from the pyrolysis of different municipal solid waste fractions

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Hui [Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China); Energy Research Institute, University of Leeds, Leeds LS2 9JT (United Kingdom); Wu, Chunfei, E-mail: c.wu@leeds.ac.uk [Energy Research Institute, University of Leeds, Leeds LS2 9JT (United Kingdom); Onwudili, Jude A. [Energy Research Institute, University of Leeds, Leeds LS2 9JT (United Kingdom); Meng, Aihong [Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China); Zhang, Yanguo, E-mail: zhangyg@tsinghua.edu.cn [Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China); Williams, Paul T., E-mail: p.t.williams@leeds.ac.uk [Energy Research Institute, University of Leeds, Leeds LS2 9JT (United Kingdom)

    2015-02-15

    Highlights: • PAH from pyrolysis of 9 MSW fractions was investigated. • Pyrolysis of plastics released more PAH than that of biomass. • Naphthalene was the most abundant PAH in the tar. • The mechanism of PAH release from biomass and plastics was proposed. - Abstract: The formation of 2–4 ring polycyclic aromatic hydrocarbons (PAH) from the pyrolysis of nine different municipal solid waste fractions (xylan, cellulose, lignin, pectin, starch, polyethylene (PE), polystyrene (PS), polyvinyl chloride (PVC), and polyethylene terephthalate (PET)) were investigated in a fixed bed furnace at 800 °C. The mass distribution of pyrolysis was also reported. The results showed that PS generated the most total PAH, followed by PVC, PET, and lignin. More PAH were detected from the pyrolysis of plastics than the pyrolysis of biomass. In the biomass group, lignin generated more PAH than others. Naphthalene was the most abundant PAH, and the amount of 1-methynaphthalene and 2-methynaphthalene was also notable. Phenanthrene and fluorene were the most abundant 3-ring PAH, while benzo[a]anthracene and chrysene were notable in the tar of PS, PVC, and PET. 2-ring PAH dominated all tar samples, and varied from 40 wt.% to 70 wt.%. For PS, PET and lignin, PAH may be generated directly from the aromatic structure of the feedstock.

  11. Temporal variability in sediment PAHs accumulation in the northern Gulf of Mexico Shelf

    Science.gov (United States)

    Bam, W.; Maiti, K.; Adhikari, P. L.

    2017-12-01

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous group of organic pollutants, some of which are known to be toxic, and/or carcinogenic to humans. The major source of these PAHs into the northern Gulf of Mexico (NGOM) are Mississippi River discharge, coastal erosion, atmospheric deposition, and numerous natural oil seeps and spills. In addition to these background source of PAHs, the Deepwater Horizon (DWH) oil spill in 2010 added 21,000 tons of PAHs into the NGOM water. In this study, we measured PAHs distribution and accumulation rates in coastal sediments near the Mississippi River mouth in 2011 and 2015 to understand the effect of DWH oil spill in PAHs accumulation in coastal sediments. Sediment cores were collected and sliced at 1 cm interval to measure PAHs concentration, and to estimate 210Pb-based sedimentation and the PAHs' accumulation rates. The results showed that the sediment deposition rates in this region varied between 0.5 to 0.9 cm/yr. The results also showed that the concentration of total PAHsPAH43) and their accumulation rates vary between 68 - 100 ng g-1 and 7 - 160 ng cm-2 yr-1, respectively. While the PAHs accumulation rate in coastal sediment varied over the years, there is no significant variation in PAHs accumulation rate before and after the DWH oil spill.

  12. Urinary concentrations of PAH and VOC metabolites in marijuana users.

    Science.gov (United States)

    Wei, Binnian; Alwis, K Udeni; Li, Zheng; Wang, Lanqing; Valentin-Blasini, Liza; Sosnoff, Connie S; Xia, Yang; Conway, Kevin P; Blount, Benjamin C

    2016-03-01

    Marijuana is seeing increased therapeutic use, and is the world's third most-popular recreational drug following alcohol and tobacco. This widening use poses increased exposure to potentially toxic combustion by-products from marijuana smoke and the potential for public health concerns. To compare urinary metabolites of polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs) among self-reported recent marijuana users and nonusers, while accounting for tobacco smoke exposure. Measurements of PAH and VOC metabolites in urine samples were combined with questionnaire data collected from participants in the National Health and Nutrition Examination Surveys (NHANES) from 2005 to 2012 in order to categorize participants (≥18years) into exclusive recent marijuana users and nonusers. Adjusted geometric means (GMs) of urinary concentrations were computed for these groups using multiple regression analyses to adjust for potential confounders. Adjusted GMs of many individual monohydroxy PAHs (OH-PAHs) were significantly higher in recent marijuana users than in nonusers (pmarijuana users than in nonusers. We found elevated levels of biomarkers for potentially harmful chemicals among self-identified, recent marijuana users compared with nonusers. These findings suggest that further studies are needed to evaluate the potential health risks to humans from the exposure to these agents when smoking marijuana. Published by Elsevier Ltd.

  13. Investigating the temporal trends in PAH, PCB and OCP ...

    African Journals Online (AJOL)

    2013-05-09

    May 9, 2013 ... mation on application of passive sampling in South Africa is available in the literature. This study was ..... molecular weight PAHs in the current study were on average up to 2 orders of magnitude lower ..... VAN REI WF (1987) The Hartbeespoort dam – a magnet to millions? In: Thornton JA and Walmsley RD ...

  14. Bioremediation of polyaromatic hydrocarbons (PAHs using rhizosphere technology

    Directory of Open Access Journals (Sweden)

    Sandeep Bisht

    2015-03-01

    Full Text Available The remediation of polluted sites has become a priority for society because of increase in quality of life standards and the awareness of environmental issues. Over the past few decades there has been avid interest in developing in situ strategies for remediation of environmental contaminants, because of the high economic cost of physicochemical strategies, the biological tools for remediation of these persistent pollutants is the better option. Major foci have been considered on persistent organic chemicals i.e.polyaromatic hydrocarbons (PAHs due to their ubiquitous occurrence, recalcitrance, bioaccumulation potential and carcinogenic activity. Rhizoremediation, a specific type of phytoremediation that involves both plants and their associated rhizospheric microbes is the creative biotechnological approach that has been explored in this review. Moreover, in this review we showed the significance of rhizoremediation of PAHs from other bioremediation strategies i.e. natural attenuation, bioaugmentation and phytoremediation and also analyze certain environmental factor that may influence the rhizoremediation technique. Numerous bacterial species were reported to degrade variety of PAHs and most of them are isolated from contaminated soil, however few reports are available from non contaminated soil. Pseudomonas aeruginosa, Pseudomons fluoresens, Mycobacterium spp., Haemophilus spp., Rhodococcus spp., Paenibacillus spp. are some of the commonly studied PAH-degrading bacteria. Finally, exploring the molecular communication between plants and microbes, and exploiting this communication to achieve better results in the elimination of contaminants, is a fascinating area of research for future perspective.

  15. MULTIMEDIA CONCENTRATIONS OF PAH IN SEVERAL DAY CARE CENTERS

    Science.gov (United States)

    Concentrations of polycyclic aromatic hydrocarbons were measured in nine day care centers in the spring of 1997. Indoor and outdoor air, food and beverages, indoor dust, and outdoor play area soil were sampled. The mean sums of 20 target PAH concentrations were 265 and 199 ng...

  16. Small phosphatidate phosphatase (TtPAH2) of Tetrahymena ...

    Indian Academy of Sciences (India)

    Anoop Narayana Pillai

    2017-10-03

    Oct 3, 2017 ... There was no significant difference (indicated as 'ns') in the number of lipid droplets as analysed by Kruskal-Wallis test. (p \\0.01). .... and Goodman JM 2011 The yeast lipin orthologue Pah1p is ... gamma transcriptional activity.

  17. Polycyclic aromatic hydrocarbons (PAH) in Danish barbecued meat

    DEFF Research Database (Denmark)

    Duedahl-Olesen, Lene; Aaslyng, Margit Dall; Meinert, Lene

    2015-01-01

    Barbecuing is known to result in the formation of polycyclic aromatic hydrocarbons (PAHs). A validated method that employed pressurized liquid extraction (PLE), gel permeation chromatography (GPC) followed by solid phase extraction (SPE) on Silica and analytical determination by GC-MS was applied...

  18. Polycyclic aromatic hydrocarbons and PAH-related DNA adducts.

    Science.gov (United States)

    Ewa, Błaszczyk; Danuta, Mielżyńska-Švach

    2017-08-01

    Investigations on the impact of chemicals on the environment and human health have led to the development of an exposome concept. The exposome refers to the totality of exposures received by a person during life, including exposures to life-style factors, from the prenatal period to death. The exposure to genotoxic chemicals and their reactive metabolites can induce chemical modifications of DNA, such as, for example, DNA adducts, which have been extensively studied and which play a key role in chemically induced carcinogenesis. Development of different methods for the identification of DNA adducts has led to adopting DNA adductomic approaches. The ability to simultaneously detect multiple PAH-derived DNA adducts may allow for the improved assessment of exposure, and offer a mechanistic insight into the carcinogenic process following exposure to PAH mixtures. The major advantage of measuring chemical-specific DNA adducts is the assessment of a biologically effective dose. This review provides information about the occurrence of the polycyclic aromatic hydrocarbons (PAHs) and their influence on human exposure and biological effects, including PAH-derived DNA adduct formation and repair processes. Selected methods used for determination of DNA adducts have been presented.

  19. PAH desorption from river floodplain soils using supercritical fluid extraction

    Czech Academy of Sciences Publication Activity Database

    Yang, Y.; Cajthaml, Tomáš; Hofmann, T.

    2008-01-01

    Roč. 156, č. 3 (2008), s. 745-752 ISSN 0269-7491 R&D Projects: GA MŠk 2B06156 Institutional research plan: CEZ:AV0Z50200510 Keywords : pahs * slow desorption * carbonaceous materials Subject RIV: EE - Microbiology, Virology Impact factor: 3.135, year: 2008

  20. Bioremediation of polyaromatic hydrocarbons (PAHs) using rhizosphere technology

    Science.gov (United States)

    Bisht, Sandeep; Pandey, Piyush; Bhargava, Bhavya; Sharma, Shivesh; Kumar, Vivek; Sharma, Krishan D.

    2015-01-01

    The remediation of polluted sites has become a priority for society because of increase in quality of life standards and the awareness of environmental issues. Over the past few decades there has been avid interest in developing in situ strategies for remediation of environmental contaminants, because of the high economic cost of physicochemical strategies, the biological tools for remediation of these persistent pollutants is the better option. Major foci have been considered on persistent organic chemicals i.e. polyaromatic hydrocarbons (PAHs) due to their ubiquitous occurrence, recalcitrance, bioaccumulation potential and carcinogenic activity. Rhizoremediation, a specific type of phytoremediation that involves both plants and their associated rhizospheric microbes is the creative biotechnological approach that has been explored in this review. Moreover, in this review we showed the significance of rhizoremediation of PAHs from other bioremediation strategies i.e. natural attenuation, bioaugmentation and phytoremediation and also analyze certain environmental factor that may influence the rhizoremediation technique. Numerous bacterial species were reported to degrade variety of PAHs and most of them are isolated from contaminated soil, however few reports are available from non contaminated soil. Pseudomonas aeruginosa , Pseudomons fluoresens , Mycobacterium spp., Haemophilus spp., Rhodococcus spp., Paenibacillus spp. are some of the commonly studied PAH-degrading bacteria. Finally, exploring the molecular communication between plants and microbes, and exploiting this communication to achieve better results in the elimination of contaminants, is a fascinating area of research for future perspective. PMID:26221084

  1. Improving bioremediation of PAH contaminated soils by thermal pretreatment

    NARCIS (Netherlands)

    Bonten, L.

    2001-01-01

    Numerous sites and large volumes of sediments in the Netherlands are contaminated with polycyclic aromatic hydrocarbons (PAH), which are of great concern because of their

  2. Effect of smoking on Polycyclic Aromatic Hydrocarbons (PAHS ...

    African Journals Online (AJOL)

    The effects of smoking on proximate composition, energy values and concentrations of polycyclic aromatic hydrocarbons (PAHs) were studied in raw and smoked samples of catfish (Clarias gariepinus) and tilapia (Oreochromis niloticus). Crude protein was higher in the tilapia sample for both raw and smoked samples.

  3. PAHs, OCPs and PCBs in sediments from three catchments in ...

    African Journals Online (AJOL)

    Based on the comparison of chemical concentrations to international sediment quality guidelines, PAH, OCP and PCB concentrations in most sediment samples posed a low risk to sediment-dwelling organisms. However, in some instances the risk was moderate or high. It is recommended that these compounds be ...

  4. PAHs molecules and heating of the interstellar gas

    Science.gov (United States)

    Verstraete, Laurent; Leger, Alain; Dhendecourt, Louis B.; Dutuit, O.; Defourneau, D.

    1989-01-01

    Until now it has remained difficult to account for the rather high temperatures seen in many diffuse interstellar clouds. Various heating mechanisms have been considered: photoionization of minor species, ionization of H by cosmic rays, and photoelectric effect on small grains. Yet all these processes are either too weak or efficient under too restricting conditions to balance the observed cooling rates. A major heat source is thus still missing in the thermal balance of the diffuse gas. Using photoionization cross sections measured in the lab, it was shown that in order to balance the observed cooling rates in cold diffuse clouds (T approx. 80 K) the PAHs would have to contain 15 percent of the cosmic abundance of carbon. This value does not contradict the former estimation of 6 percent deduced from the IR emission bands since this latter is to be taken as a lower limit. Further, it was estimated that the contribution to the heating rate due to PAH's in a warm HI cloud, assuming the same PAH abundance as for a cold HI cloud, would represent a significant fraction of the value required to keep the medium in thermal balance. Thus, photoionization of PAHs might well be a major heat source for the cold and warm HI media.

  5. Excessive masturbation after epilepsy surgery.

    Science.gov (United States)

    Ozmen, Mine; Erdogan, Ayten; Duvenci, Sirin; Ozyurt, Emin; Ozkara, Cigdem

    2004-02-01

    Sexual behavior changes as well as depression, anxiety, and organic mood/personality disorders have been reported in temporal lobe epilepsy (TLE) patients before and after epilepsy surgery. The authors describe a 14-year-old girl with symptoms of excessive masturbation in inappropriate places, social withdrawal, irritability, aggressive behavior, and crying spells after selective amygdalohippocampectomy for medically intractable TLE with hippocampal sclerosis. Since the family members felt extremely embarrassed, they were upset and angry with the patient which, in turn, increased her depressive symptoms. Both her excessive masturbation behavior and depressive symptoms remitted within 2 months of psychoeducative intervention and treatment with citalopram 20mg/day. Excessive masturbation is proposed to be related to the psychosocial changes due to seizure-free status after surgery as well as other possible mechanisms such as Kluver-Bucy syndrome features and neurophysiologic changes associated with the cessation of epileptic discharges. This case demonstrates that psychiatric problems and sexual changes encountered after epilepsy surgery are possibly multifactorial and in adolescence hypersexuality may be manifested as excessive masturbation behavior.

  6. Influence of infrared final cooking on polycyclic aromatic hydrocarbon formation in ohmically pre-cooked beef meatballs.

    Science.gov (United States)

    Kendirci, Perihan; Icier, Filiz; Kor, Gamze; Onogur, Tomris Altug

    2014-06-01

    Effects of infrared cooking on polycyclic aromatic hydrocarbon (PAH) formation in ohmically pre-cooked beef meatballs were investigated. Samples were pre-cooked in a specially designed-continuous type ohmic cooking at a voltage gradient of 15.26V/cm for 92s. Infrared cooking was applied as a final cooking method at different combinations of heat fluxes (3.706, 5.678, 8.475kW/m(2)), application distances (10.5, 13.5, 16.5cm) and application durations (4, 8, 12min). PAHs were analyzed by using high performance liquid chromatography (HPLC) equipped with a fluorescence detector. The total PAH levels were detected to be between 4.47 and 64μg/kg. Benzo[a] pyrene (B[a]P) and PAH4 (sum of B[a]P, chrysene (Chr), benzo[a]anthracene (B[a]A) and benzo[b]fluoranthene (B[b]F)) levels detected in meatballs were below the EC limits. Ohmic pre-cooking followed by infrared cooking may be regarded as a safe cooking procedure of meatballs from a PAH contamination point of view. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. In situ treatment of soil contaminated with PAHs and phenols

    International Nuclear Information System (INIS)

    Sresty, G.; Dev, H.; Chang, J.; Houthoofd, J.

    1992-01-01

    The wood preserving industry uses more pesticides than any other industry worldwide. The major chemicals used are creosote, pentachlorophenol, and CCA (copper, chrome and arsenate). It is reported that between 415 to 550 creosoting operations within the United States consume approximately 454,000 metric tons of creosote annually. When properly used and disposed off, creosote does not appear to significantly threaten human health. However, due to improper disposal and spillage at old facilities, creosote and other wood preserving chemicals have found their way into surface soils. Active wood preserving sites generate an estimated 840 to 1530 dry metric tons of hazardous contaminated sludge annually, which is classified as KOOL. Creosote, obtained from coal tar, contains a large number of chemical components. The three main families of compounds represented in creosote are: polycyclic aromatic hydrocarbons (PAH), phenolic, and heterocyclic compounds. Creosote is composed of approximately 85% PAHs, 10% phenolic compounds and 5% heterocyclic compounds. There are approximately a total of 17 PAHs present in creosote. The four most prominent compounds belonging to the PAH family are naphthalene, 2-methylnaphthalene, phenanthrene, and anthracene. These four compounds represent approximately 52% of the total PAHs present in creosote. There are approximately 12 different phenolic compounds present in creosote among which phenol is the most abundant, representing 20% of the total phenolics. In addition, the various isomers of cresol represent about 20% and pentachlorophenol (PCP) represents 10% of the total phenolics. There are approximately 13 different heterocyclic compounds are the most abundant, representing approximately 70% of the total heterocyclics. All of these compounds possess toxic properties and some of them, for example, PCP, when subjected to high temperature environments are suspected precursors in the formation of dioxins

  8. Characteristics of particulate PAHs during a typical haze episode in Guangzhou, China

    Science.gov (United States)

    Tan, Jihua; Guo, Songjun; Ma, Yongliang; Duan, Jingchun; Cheng, Yuan; He, Kebin; Yang, Fumo

    2011-10-01

    The concentrations of polycyclic aromatic hydrocarbons (PAHs) in PM 2.5 and TSP were measured in Guangzhou during a typical haze episode. This episode included NH (non-haze, 3 days), HFN (haze when air masses from north and northeast, 6 days) and HFS (haze when air masses from south, 4 days). The air quality in HFN was much worse than that in NH and HFS. The total average concentrations of PAHs in PM 2.5 were 13.25 ng m -3, 59.82 ng m -3 and 13.09 ng m -3 in NH, HFN and HFS, respectively. It indicated PAH pollution had been substantially aggravated by HFN. PAHs(5 + 6) were the most abundant compounds in HFN and HFS, which accounted for 55-75% of total concentration of PAHs, while PAHs(3 + 4) were the most abundant compounds in NH, which accounted for 54-67% of total concentration of PAHs. TEF (Toxic Equivalency Factors)-adjusted concentrations of 13 particulate PAHs were very high in HFN, indicating high health risks to humans for PAH exposure in HFN. The characteristic ratios of PAHs indicated coal combustion and traffic emission were the major contributors to PAHs in HFN and HFS. The concentrations of particulate PAHs in haze episode were strongly affected by wind speed and wind direction. PAHs in NH could be from long-range transport with high north wind speed, while local emission could be the main contributor of particle-associated PAHs in HFN. The transport speed of air masses was found to play an important role on PAH concentrations.

  9. Coal-tar-based sealcoated pavement: A major PAH source to urban stream sediments

    International Nuclear Information System (INIS)

    Witter, Amy E.; Nguyen, Minh H.; Baidar, Sunil; Sak, Peter B.

    2014-01-01

    We used land-use analysis, PAH concentrations and assemblages, and multivariate statistics to identify sediment PAH sources in a small (∼1303 km 2 ) urbanizing watershed located in South-Central, Pennsylvania, USA. A geographic information system (GIS) was employed to quantify land-use features that may serve as PAH sources. Urban PAH concentrations were three times higher than rural levels, and were significantly and highly correlated with combined residential/commercial/industrial land use. Principal components analysis (PCA) was used to group sediments with similar PAH assemblages, and correlation analysis compared PAH sediment assemblages to common PAH sources. The strongest correlations were observed between rural sediments (n = 7) and coke-oven emissions sources (r = 0.69–0.78, n = 5), and between urban sediments (n = 22) and coal-tar-based sealcoat dust (r = 0.94, n = 47) suggesting that coal-tar-based sealcoat is an important urban PAH source in this watershed linked to residential and commercial/industrial land use. -- Highlights: • Total PAH concentrations were measured at 35 sites along an urbanizing land-use gradient. • PAH concentrations increased with increasing urban land-use. • Urban land-use metrics were measured at three spatial scales using GIS. • PAH assemblages indicate coal-tar-based sealcoat is a major urban PAH source. • PAH assemblages indicate coke-oven emissions are an important rural PAH source. -- Coal-tar-based sealcoated pavement is a major PAH source to urban freshwater stream sediments in south-central Pennsylvania, USA

  10. Polycyclic aromatic hydrocarbons (PAHs) in Austin sediments after a ban on pavement sealers

    Energy Technology Data Exchange (ETDEWEB)

    DeMott, R.P.; Gauthier, T.D.; Wiersema, J.M.; Crenson, G. [ENVIRON International, Tampa, FL (USA)

    2010-07-01

    Polycyclic aromatic hydrocarbon (PAH) concentrations were measured in stream sediments collected before and after a municipal ban on the use of coal-tar-based pavement sealers in Austin, Texas. Samples were collected in October 2005, prior to the ban, and again in April, 2008, approximately 2 years after the ban. Differences in total PAH concentrations between samples collected before and after the ban show no net change in PAH levels in Austin stream sediments. Results of hydrocarbon fingerprinting reveal subtle differences in PAH profiles that appear to reflect the effects of weathering rather than a change in PAH sources.

  11. Review of PAH contamination in food products and their health hazards.

    Science.gov (United States)

    Bansal, Vasudha; Kim, Ki-Hyun

    2015-11-01

    Public concern over the deleterious effects of polycyclic aromatic hydrocarbons (PAHs) has grown rapidly due to recognition of their toxicity, carcinogenicity, and teratogenicity. The aim of this review is to describe the status of PAH pollution among different food types, the route of dietary intake, measures for its reduction, and legislative approaches to control PAH. To this end, a comprehensive review is outlined to evaluate the status of PAH contamination in many important food categories along with dietary recommendations. Our discussion is also extended to describe preventive measures to reduce PAH in food products to help reduce the risks associated with human intake. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Fast analysis of 29 polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs with ultra-high performance liquid chromatography-atmospheric pressure photoionization-tandem mass spectrometry

    Science.gov (United States)

    Lung, Shih-Chun Candice; Liu, Chun-Hu

    2015-01-01

    Polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs are ubiquitous in the environment. Some of them are probable carcinogens and some are source markers. This work presents an ultra-high performance liquid chromatography-atmospheric pressure photoionization-tandem mass spectrometry (UHPLC-APPI-MS/MS) method for simultaneous analysis of 20 PAHs and nine nitro-PAHs. These compounds are separated in 15 minutes in the positive mode and 11 minutes in the negative mode, one half of GC/MS analysis time. Two pairs of precursor/product ions are offered, which is essential for confirmation. This method separates and quantifies benzo[a]pyrene (the most toxic PAHs) and non-priority benzo[e]pyrene (isomers, little toxicity) to avoid overestimation of toxin levels, demonstrating its importance for health-related researches. With 0.5% 2,4-difluoroanisole in chlorobenzene as the dopant, limits of detection of PAHs except acenaphthylene and those of nitro-PAHs except 2-nitrofluoranthene are below 10 pg and 3 pg, respectively, mostly lower than or comparable to those reported using LC-related systems. The responses were linear over two orders of magnitude with fairly good accuracy and precision. Certified reference materials and real aerosol samples were analyzed to demonstrate its applicability. This fast, sensitive, and reliable method is the first UHPLC-APPI-MS/MS method capable of simultaneously analyzing 29 environmentally and toxicologically important PAHs and nitro-PAHs. PMID:26265155

  13. Emission characterization and δ"1"3C values of parent PAHs and nitro-PAHs in size-segregated particulate matters from coal-fired power plants

    International Nuclear Information System (INIS)

    Wang, Ruwei; Yousaf, Balal; Sun, Ruoyu; Zhang, Hong; Zhang, Jiamei; Liu, Guijian

    2016-01-01

    Highlights: • pPAHs and NPAHs were strongly associated with PM_1_–_2_._5 and PM_1 compared with PM_2_._5_–_1_0. • Combustion conditions and WFGD showed typical effects on PAH level and profile. • Diagnostic ratio of PAH was to indicative of emission sources to a certain degree. • δ"1"3C values of PAHs were useful for differentiating coal combustion source. • δ"1"3C values of PAHs were unable to differentiate coal-processing sources. - Abstract: The objective of this study was to characterize parent polycyclic aromatic hydrocarbons (pPAHs) and their nitrated derivatives (NPAHs) in coarse (PM_2_._5_–_1_0), intermediate (PM_1_–_2_._5) and fine (PM_1) particulate matters emitted from coal-fired power plants (CFPPs) in Huainan, China. The diagnostic ratios and the stable carbon isotopic approaches to characterize individual PAHs were applied in order to develop robust tools for tracing the origins of PAHs in different size-segregated particular matters (PMs) emitted CFPP coal combustion. The concentrations of PAH compounds in flue gas emissions varied greatly, depending on boiler types, operation and air pollution control device (APCD) conditions. Both pPAHs and NPAHs were strongly enriched in PM_1_–_2_._5 and PM_1. In contrary to low molecular weight (LMW) PAHs, high molecular weight (HMW) PAHs were more enriched in finer PMs. The PAH diagnostic ratios in size-segregated PMs are small at most cases, highlighting their potential application in tracing CFPP emitted PAHs attached to different sizes of PMs. Yet, substantial uncertainty still exists to directly apply PAH diagnostic ratios as emission tracers. Although the stable carbon isotopic composition of PAH molecular was useful in differentiating coal combustion emissions from other sources such as biomass combustion and vehicular exhausts, it was not feasible to differentiate isotopic fractionation processes such as low-temperature carbonization, high-temperature carbonization, gasification and

  14. Emission characterization and δ{sup 13}C values of parent PAHs and nitro-PAHs in size-segregated particulate matters from coal-fired power plants

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ruwei [CAS Key Laboratory of Crust-Mantle Materials and the Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026 (China); State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, The Chinese Academy of Sciences, Xi’an 710075 Shaanxi (China); Yousaf, Balal; Sun, Ruoyu [CAS Key Laboratory of Crust-Mantle Materials and the Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026 (China); Zhang, Hong [Anhui Department of Environmental Protection, Anhui Academy of Environmental Science, Hefei 230071 (China); Zhang, Jiamei [CAS Key Laboratory of Crust-Mantle Materials and the Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026 (China); Liu, Guijian, E-mail: lgj@ustc.edu.cn [CAS Key Laboratory of Crust-Mantle Materials and the Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026 (China); State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, The Chinese Academy of Sciences, Xi’an 710075 Shaanxi (China)

    2016-11-15

    Highlights: • pPAHs and NPAHs were strongly associated with PM{sub 1–2.5} and PM{sub 1} compared with PM{sub 2.5–10}. • Combustion conditions and WFGD showed typical effects on PAH level and profile. • Diagnostic ratio of PAH was to indicative of emission sources to a certain degree. • δ{sup 13}C values of PAHs were useful for differentiating coal combustion source. • δ{sup 13}C values of PAHs were unable to differentiate coal-processing sources. - Abstract: The objective of this study was to characterize parent polycyclic aromatic hydrocarbons (pPAHs) and their nitrated derivatives (NPAHs) in coarse (PM{sub 2.5–10}), intermediate (PM{sub 1–2.5}) and fine (PM{sub 1}) particulate matters emitted from coal-fired power plants (CFPPs) in Huainan, China. The diagnostic ratios and the stable carbon isotopic approaches to characterize individual PAHs were applied in order to develop robust tools for tracing the origins of PAHs in different size-segregated particular matters (PMs) emitted CFPP coal combustion. The concentrations of PAH compounds in flue gas emissions varied greatly, depending on boiler types, operation and air pollution control device (APCD) conditions. Both pPAHs and NPAHs were strongly enriched in PM{sub 1–2.5} and PM{sub 1}. In contrary to low molecular weight (LMW) PAHs, high molecular weight (HMW) PAHs were more enriched in finer PMs. The PAH diagnostic ratios in size-segregated PMs are small at most cases, highlighting their potential application in tracing CFPP emitted PAHs attached to different sizes of PMs. Yet, substantial uncertainty still exists to directly apply PAH diagnostic ratios as emission tracers. Although the stable carbon isotopic composition of PAH molecular was useful in differentiating coal combustion emissions from other sources such as biomass combustion and vehicular exhausts, it was not feasible to differentiate isotopic fractionation processes such as low-temperature carbonization, high

  15. Ability of natural attenuation and phytoremediation using maize (Zea mays L.) to decrease soil contents of polycyclic aromatic hydrocarbons (PAHs) derived from biomass fly ash in comparison with PAHs-spiked soil.

    Science.gov (United States)

    Košnář, Zdeněk; Mercl, Filip; Tlustoš, Pavel

    2018-05-30

    A 120-day pot experiment was conducted to compare the ability of natural attenuation and phytoremediation approaches to remove polycyclic aromatic hydrocarbons (PAHs) from soil amended with PAHs-contaminated biomass fly ash. The PAH removal from ash-treated soil was compared with PAHs-spiked soil. The removal of 16 individual PAHs from soil ranged between 4.8% and 87.8% within the experiment. The natural attenuation approach led to a negligible total PAH removal. The phytoremediation was the most efficient approach for PAH removal, while the highest removal was observed in the case of ash-treated soil. The content of low molecular weight (LMW) PAHs and the total PAHs in this treatment significantly decreased (P <.05) over the whole experiment by 47.6% and 29.4%, respectively. The tested level of PAH soil contamination (~1600 µg PAH/kg soil dry weight) had no adverse effects on maize growth as well on the biomass yield. In addition, the PAHs were detected only in maize roots and their bioaccumulation factors were significantly lower than 1 suggesting negligible PAH uptake from soil by maize roots. The results showed that PAHs of ash origin were similarly susceptible to removal as spiked PAHs. The presence of maize significantly boosted the PAH removal from soil and its aboveground biomass did not represent any environmental risk. Copyright © 2018 Elsevier Inc. All rights reserved.

  16. Decontamination of PAH polluted soils by fungi. Subproject: PAH degradation balance and testing of the extended laboratory process. Final report

    International Nuclear Information System (INIS)

    Martens, R.; Zadrazil, F.; Wolter, M.; Bahadir, M.

    1997-01-01

    The aim of the research project was first to select a fungus with a high potential for mineralization of polycyclic aromatic hydrocarbons (PAH) and a good ability to colonize different soils. The application of this fungus for a degradation of PAH in soil had to be tested. In a screening of 57 white rot fungi the fungus Pleurotus sp. Florida fulfilled these requirements best. In pure culture it was able to metabolize and mineralize highly condensed 4-6 ring PAH to a great extent. For instance, up to 50% of 14 C-pyrene or 39% of 14 C-benzo(a)pyrene was mineralized to 14 CO 2 within 15 weeks. If different carriers for 14 C-pyrene were used the mineralization correlated with the bioavailability, which was characterized by the desorption of the compound from the carriers with water. The mineralization of 14 C-pyrene, 14 C-benz(a)anthracene; 14 C-benzo(a)-pyrene and 14 C-dibenz(a, h)anthracene in native soils showed that a colonization with Pl. sp Florida inhibited the degradation of the less recalcitrant 14 C-pyrene by the indigenous soil microflora. However, the mineralization of the carcinogenic, very recalcitrant and high condensed 14 C-PAH was considerably supported by the fungus. Therefore this capabilities of the fungus could not be proven in a joint medium-scale soil experiment (0.8 m 3 soil) which had been conducted within a parmership with scientists in Jena and an industriell firm. Because of safety aspects only the low condensed less recalcitrant PAH could be applied in this experiment. (orig./MG) [de

  17. Excess Early Mortality in Schizophrenia

    DEFF Research Database (Denmark)

    Laursen, Thomas Munk; Nordentoft, Merete; Mortensen, Preben Bo

    2014-01-01

    Schizophrenia is often referred to as one of the most severe mental disorders, primarily because of the very high mortality rates of those with the disorder. This article reviews the literature on excess early mortality in persons with schizophrenia and suggests reasons for the high mortality...... as well as possible ways to reduce it. Persons with schizophrenia have an exceptionally short life expectancy. High mortality is found in all age groups, resulting in a life expectancy of approximately 20 years below that of the general population. Evidence suggests that persons with schizophrenia may...... not have seen the same improvement in life expectancy as the general population during the past decades. Thus, the mortality gap not only persists but may actually have increased. The most urgent research agenda concerns primary candidates for modifiable risk factors contributing to this excess mortality...

  18. Severe rhabdomyolysis after excessive bodybuilding.

    Science.gov (United States)

    Finsterer, J; Zuntner, G; Fuchs, M; Weinberger, A

    2007-12-01

    A 46-year-old male subject performed excessive physical exertion during 4-6 h in a studio for body builders during 5 days. He was not practicing sport prior to this training and denied the use of any aiding substances. Despite muscle aching already after 1 day, he continued the exercises. After the last day, he recognized tiredness and cessation of urine production. Two days after discontinuation of the training, a Herpes simplex infection occurred. Because of acute renal failure, he required hemodialysis. There were absent tendon reflexes and creatine kinase (CK) values up to 208 274 U/L (normal: <170 U/L). After 2 weeks, CK had almost normalized and, after 4 weeks, hemodialysis was discontinued. Excessive muscle training may result in severe, hemodialysis-dependent rhabdomyolysis. Triggering factors may be prior low fitness level, viral infection, or subclinical metabolic myopathy.

  19. Infrared study of seven possible compact H II regions

    International Nuclear Information System (INIS)

    Sibille, F.; Lunel, M.; Bergeat, J.

    1976-01-01

    We report observations of seven possible compact H II regions in the infrared with the hydrogen spectrum in order to derive extinction and emission measures. The emission measure is compared with available radio data. For two sources, agreement is found between radio and infrared data. Infrared excess is found in four sources, its origin is discussed. Two sources cannot be interpreted as compact H II regions. (orig.) [de

  20. Polycyclic Aromatic Hydrocarbons (PAHs) and their Bioaccessibility in Meat: a Tool for Assessing Human Cancer Risk.

    Science.gov (United States)

    Hamidi, Elliyana Nadia; Hajeb, Parvaneh; Selamat, Jinap; Abdull Razis, Ahmad Faizal

    2016-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are primarily formed as a result of thermal treatment of food, especially barbecuing or grilling. Contamination by PAHs is due to generation by direct pyrolysis of food nutrients and deposition from smoke produced through incomplete combustion of thermal agents. PAHs are ubiquitous compounds, well-known to be carcinogenic, which can reach the food in different ways. As an important human exposure pathway of contaminants, dietary intake of PAHs is of increasing concern for assessing cancer risk in the human body. In addition, the risks associated with consumption of barbecued meat may increase if consumers use cooking practices that enhance the concentrations of contaminants and their bioaccessibility. Since total PAHs always overestimate the actual amount that is available for absorption by the body, bioaccessibility of PAHs is to be preferred. Bioaccessibility of PAHs in food is the fraction of PAHs mobilized from food matrices during gastrointestinal digestion. An in vitro human digestion model was chosen for assessing the bioaccessibility of PAHs in food as it offers a simple, rapid, low cost alternative to human and animal studies; providing insights which may not be achievable in in vivo studies. Thus, this review aimed not only to provide an overview of general aspects of PAHs such as the formation, carcinogenicity, sources, occurrence, and factors affecting PAH concentrations, but also to enhance understanding of bioaccessibility assessment using an in vitro digestion model.

  1. Polynuclear aromatic hydrocarbons (PAHs) mediate cadmium toxicity to an emergent wetland species

    International Nuclear Information System (INIS)

    Zhang, Zhenhua; Rengel, Zed; Meney, Kathy; Pantelic, Ljiljana; Tomanovic, Radmila

    2011-01-01

    Growth and pollutant removal by emergent wetland plants may be influenced by interactions among mixed pollutants in constructed wetlands. A glasshouse experiment was conducted to investigate interactive effects of cadmium (Cd) x polynuclear aromatic hydrocarbons (PAHs) x plant treatments on growth of Juncus subsecundus, Cd and PAH removal from soil and the total number of microorganisms in soil. Growth and biomass of J. subsecundus were significantly influenced by interaction of Cd and PAHs, significantly decreasing with either Cd or PAH additions, but with the effect of Cd on plant growth being stronger than that of PAHs. The mixture of low Cd and low PAH lessened Cd toxicity to plants, resulting in improved plant growth and increased Cd accumulation in plant tissues, thus enhancing Cd removal by plants. The dissipation of PAHs in soils was significantly influenced by interactions of Cd, PAH and plant presence or absence. The total number of microorganisms in soils was significantly increased by the PAH additions. The interactive effect of Cd and PAHs on plant growth may be linked to the changes in the abundance of microorganisms in the rhizosphere, probably via a positive effect of PAH metabolites and/or phytohormones produced by microorganisms on plant growth.

  2. Spatial Distribution of Polycyclic Aromatic Hydrocarbon (PAH) Concentrations in Soils from Bursa, Turkey.

    Science.gov (United States)

    Karaca, Gizem

    2016-02-01

    The objectives of this study were to identify regional variations in soil polycyclic aromatic hydrocarbon (PAH) contamination in Bursa, Turkey, and to determine the distributions and sources of various PAH species and their possible sources. Surface soil samples were collected from 20 different locations. The PAH concentrations in soil samples were analyzed using gas chromatography-mass spectrometry (GC-MS). The total PAH concentrations (∑12 PAH) varied spatially between 8 and 4970 ng/g dry matter (DM). The highest concentrations were measured in soils taken from traffic+barbecue+ residential areas (4970 ng/g DM) and areas with cement (4382 ng/g DM) and iron-steel (4000 ng/g DM) factories. In addition, the amounts of ∑7 carcinogenic PAH ranged from 1 to 3684 ng/g DM, and between 5 and 74 % of the total PAHs consisted of such compounds. Overall, 4-ring PAH compounds (Fl, Pyr, BaA and Chr) were dominant in the soil samples, with 29-82 % of the ∑12 PAH consisting of 4-ring PAH compounds. The ∑12 BaPeq values ranged from 0.1 to 381.8 ng/g DM. Following an evaluation of the molecular diagnostic ratios, it was concluded that the PAH pollution in Bursa soil was related to pyrolytic sources; however, the impact of petrogenic sources should not be ignored.

  3. Interspecies and spatial trends in polycyclic aromatic hydrocarbons (PAHs) in Atlantic and Mediterranean pelagic seabirds

    International Nuclear Information System (INIS)

    Roscales, Jose L.; Gonzalez-Solis, Jacob; Calabuig, Pascual; Jimenez, Begona

    2011-01-01

    PAHs were analyzed in the liver of 5 species of pelagic seabirds (Procellariiformes) from the northeast Atlantic and the Mediterranean. The main objective was to assess the trophic and geographic trends of PAHs in seabirds to evaluate their suitability as bioindicators of chronic marine pollution by these compounds. Although higher levels of PAHs have been described in the Mediterranean compared to other oceanic regions, we did not find significant spatial patterns and observed only minor effects of the geographic origin on seabird PAHs. However, we found significant higher PAH levels in petrel compared to shearwater species, which could be related to differences in their exploitation of mesopelagic and epipelagic resources, respectively, and the vertical dynamic of PAHs in the water column. Overall, although this study enhances the need of multi-species approaches to show a more comprehensive evaluation of marine pollution, seabirds emerged as poor indicators of pelagic chronic PAH levels. - Highlights: → PAHs in pelagic seabirds show specific inter-species patterns related to trophic ecology. → Geographic origin shows a minor effect over PAH levels in pelagic seabirds. → Pelagic seabirds seem to be poor indicators of chronic PAH levels. - PAH levels in Atlantic and Mediterranean pelagic seabirds show specific inter-species patterns related to trophic ecology but a minor influence of their geographic origin.

  4. Mass balance-based regression modeling of PAHs accumulation in urban soils, role of urban development

    International Nuclear Information System (INIS)

    Peng, Chi; Wang, Meie; Chen, Weiping; Chang, Andrew C.

    2015-01-01

    We investigated the polycyclic aromatic hydrocarbons (PAHs) contents in 68 soils samples collected at housing developments that represent different length of development periods across Beijing. Based on the data, we derived a mass balanced mathematical model to simulate the dynamics of PAH accumulations in urban soils as affected by the urban developments. The key parameters were estimated by fitting the modified mass balance model to the data of PAH concentrations vs. building age of the sampling green area. The total PAH concentrations would increase from the baseline of 267 ng g −1 to 3631 ng g −1 during the period of 1978–2048. It showed that the dynamic changes in the rates of accumulations of light and heavy PAH species were related to the shifting of sources of fuels, combustion efficiencies, and amounts of energy consumed during the course of development. - Highlights: • Introduced a mass balance model for soil PAHs accumulation with urbanization. • Reconstructed the historical data of PAH accumulation in soil of Beijing, China. • The soil PAH concentrations would be doubled in the following 40 years. • The composition of PAH emissions were shifting to light PAH species. - Introduced a regression modeling approach to predict the changes of PAH concentrations in urban soil

  5. Watershed-scale modeling on the fate and transport of polycyclic aromatic hydrocarbons (PAHs)

    International Nuclear Information System (INIS)

    Ligaray, Mayzonee; Baek, Sang Soo; Kwon, Hye-Ok; Choi, Sung-Deuk; Cho, Kyung Hwa

    2016-01-01

    PAHs are potentially carcinogenic substances that are persistent in the environment. Increasing concentrations of PAHs were observed due to rapid urbanization, thus; monitoring PAHs concentrations is necessary. However, it is expensive to conduct intensive monitoring activities of a large number of PAHs. This study addressed this issue by developing a multimedia model coupled with a hydrological model (i.e., Soil and Water Assessment Tool (SWAT)) for Taehwa River (TR) watershed in Ulsan, the industrial capital of South Korea. The hydrologic module of the SWAT was calibrated, and further used to simulate the fate and transport of PAHs in soil and waterbody. The model demonstrated that the temporal or seasonal variation of PAHs in soil and waterbody can be well reproduced. Meanwhile, the spatial distribution of PAHs showed that urban areas in TR watershed have the highest PAH loadings compared to rural areas. Sensitivity analyses of the PAH soil and PAH water parameters were also able to determine the critical processes in TR watershed: degradation, deposition, volatilization, and wash off mechanism. We hope that this model will be able to aid the stakeholders in: regulating PAH concentrations emitted by various sources; and also apply the model to other Persistent Organic Pollutants (POPs).

  6. Watershed-scale modeling on the fate and transport of polycyclic aromatic hydrocarbons (PAHs)

    Energy Technology Data Exchange (ETDEWEB)

    Ligaray, Mayzonee; Baek, Sang Soo [School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology, UNIST-gil 50, Ulsan 44919 (Korea, Republic of); Kwon, Hye-Ok [Disaster Scientific Investigation Division, National Disaster Management Research Institute, 365 Jongga-ro Jung-gu, Ulsan 44538 (Korea, Republic of); Choi, Sung-Deuk, E-mail: sdchoi@unist.ac.kr [School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology, UNIST-gil 50, Ulsan 44919 (Korea, Republic of); Cho, Kyung Hwa, E-mail: khcho@unist.ac.kr [School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology, UNIST-gil 50, Ulsan 44919 (Korea, Republic of)

    2016-12-15

    PAHs are potentially carcinogenic substances that are persistent in the environment. Increasing concentrations of PAHs were observed due to rapid urbanization, thus; monitoring PAHs concentrations is necessary. However, it is expensive to conduct intensive monitoring activities of a large number of PAHs. This study addressed this issue by developing a multimedia model coupled with a hydrological model (i.e., Soil and Water Assessment Tool (SWAT)) for Taehwa River (TR) watershed in Ulsan, the industrial capital of South Korea. The hydrologic module of the SWAT was calibrated, and further used to simulate the fate and transport of PAHs in soil and waterbody. The model demonstrated that the temporal or seasonal variation of PAHs in soil and waterbody can be well reproduced. Meanwhile, the spatial distribution of PAHs showed that urban areas in TR watershed have the highest PAH loadings compared to rural areas. Sensitivity analyses of the PAH soil and PAH water parameters were also able to determine the critical processes in TR watershed: degradation, deposition, volatilization, and wash off mechanism. We hope that this model will be able to aid the stakeholders in: regulating PAH concentrations emitted by various sources; and also apply the model to other Persistent Organic Pollutants (POPs).

  7. Vegetative cover and PAHs accumulation in soils of urban green space

    International Nuclear Information System (INIS)

    Peng Chi; Ouyang Zhiyun; Wang Meie; Chen Weiping; Jiao Wentao

    2012-01-01

    We investigated how urban land uses influence soil accumulation of polycyclic aromatic hydrocarbons (PAHs) in the urban green spaces composed of different vegetative cover. How did soil properties, urbanization history, and population density affect the outcomes were also considered. Soils examined were obtained at 97 green spaces inside the Beijing metropolis. PAH contents of the soils were influenced most significantly by their proximity to point source of industries such as the coal combustion installations. Beyond the influence circle of industrial emissions, land use classifications had no significant effect on the extent of PAH accumulation in soils. Instead, the nature of vegetative covers affected PAH contents of the soils. Tree–shrub–herb and woodland settings trapped more airborne PAH and soils under these vegetative patterns accumulated more PAHs than those of the grassland. Urbanization history, population density and soil properties had no apparent impact on PAHs accumulations in soils of urban green space. - Highlights: ► Land use did not affect PAHs in soils except for areas adjacent to industrial sources. ► Tree–shrub–herb and woodland cover amass more PAHs in soils than grassland cover. ► Urban development and soil property factors had little effect on PAHs in soils. - Industrial emissions aside, vegetative cover is the dominant factor controlling accumulation of PAHs in urban green space soils.

  8. Polycyclic Aromatic Hydrocarbon (PAH Exposure and DNA Adduct Semi-Quantitation in Archived Human Tissues

    Directory of Open Access Journals (Sweden)

    M. Margaret Pratt

    2011-06-01

    Full Text Available Polycyclic aromatic hydrocarbons (PAHs are combustion products of organic materials, mixtures of which contain multiple known and probable human carcinogens. PAHs occur in indoor and outdoor air, as well as in char-broiled meats and fish. Human exposure to PAHs occurs by inhalation, ingestion and topical absorption, and subsequently formed metabolites are either rendered hydrophilic and excreted, or bioactivated and bound to cellular macromolecules. The formation of PAH-DNA adducts (DNA binding products, considered a necessary step in PAH-initiated carcinogenesis, has been widely studied in experimental models and has been documented in human tissues. This review describes immunohistochemistry (IHC studies, which reveal localization of PAH-DNA adducts in human tissues, and semi-quantify PAH-DNA adduct levels using the Automated Cellular Imaging System (ACIS. These studies have shown that PAH-DNA adducts concentrate in: basal and supra-basal epithelium of the esophagus, cervix and vulva; glandular epithelium of the prostate; and cytotrophoblast cells and syncitiotrophoblast knots of the placenta. The IHC photomicrographs reveal the ubiquitous nature of PAH-DNA adduct formation in human tissues as well as PAH-DNA adduct accumulation in specific, vulnerable, cell types. This semi-quantative method for PAH-DNA adduct measurement could potentially see widespread use in molecular epidemiology studies.

  9. Atmospheric polycyclic aromatic hydrocarbons (PAHs) in Asia: A review from 1999 to 2004

    International Nuclear Information System (INIS)

    Chang, K.-F.; Fang, G.-C.; Chen, J.-C.; Wu, Y.-S.

    2006-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are present in both gaseous and particulate phases. These compounds are considered to be atmospheric contaminants and are human carcinogens. Many studies have monitored atmospheric particulate and gaseous phases of PAH in Asia over the past 5 years. This work compares and discusses different sample collection, pretreatment and analytical methods. The main PAH sources are traffic exhausts (AcPy, FL, Flu, PA, Pyr, CHR, BeP) and industrial emissions (BaP, BaA, PER, BeP, COR, CYC). PAH concentrations are highest in areas of traffic, followed by the urban sites, and lowest in rural sites. Meteorological conditions, such as temperature, wind speed and humidity, strongly affect PAH concentrations at all sampling sites. This work elucidates the characteristics, sources and distribution, and the healthy impacts of atmospheric PAH species in Asia. - This work summarizes the characteristics, sources and distribution, and the healthy impacts of atmospheric PAH species in Asia

  10. Distribution and origin sources of Polycyclic Aromatic Hydrocarbons (PAHs) pollution in sediment of Sarawak coastal area

    International Nuclear Information System (INIS)

    Mohd Shuhaimi Elias; Abdul Khalik Wood; Zaleha Hashim; Mohd Suhaimi Hamzah; Shamsiah Abdul Rahman; Nazaratul Ashifa Abdullah Salim

    2010-01-01

    Alkyl and parent Polycyclic Aromatic Hydrocarbons (PAHs) compounds in marine sediment sample collected from ten locations along Sarawak coastal areas were extracted and analyzed by using gas chromatography-mass spectrometry. The source identification of PAH pollution in marine sediment of Sarawak coastal areas were identify by ratios technique of An/ An+phen, Fl/ Fl +Py, B[a]A/ (B[a]A+Chry) and total Methyl Phen/ Phen. The total alkyl and parent PAHs concentration varies from 36.5 - 277.4 ng/ g dry weight (d.w.) with a mean concentration of 138.2 ng/ g d.w. The ratio values of PAHs pollution in marine sediment of Sarawak coastal areas are clearly indicating the PAHs pollutions are originated from petroleum (petrogenic) and petroleum combustion (pyrolytic). However, the origin sources of PAHs pollution in a few stations were uncertain due to mixing sources of PAHs. (author)

  11. Enrichment behavior and transport mechanism of soil-bound PAHs during rainfall-runoff events.

    Science.gov (United States)

    Zheng, Yi; Luo, Xiaolin; Zhang, Wei; Wu, Bin; Han, Feng; Lin, Zhongrong; Wang, Xuejun

    2012-12-01

    Polycyclic Aromatic Hydrocarbons (PAHs) transported by surface runoff result in nonpoint source pollution and jeopardize aquatic ecosystems. The transport mechanism of PAHs during rainfall-runoff events has been rarely studied regarding pervious areas. An experimental system was setup to simulate the runoff pollution process on PAHs-contaminated soil. The enrichment behavior of soil-bound PAHs was investigated. The results show that soil organic matters (SOM), rather than clay particles, seem to be the main carrier of PAHs. The enrichment is highly conditioned on runoff and erosion processes, and its magnitude varies among PAH compounds. It is not feasible to build a simple and universal relationship between enrichment ratio and sediment discharge following the traditional enrichment theory. To estimate the flux of PAHs from pervious areas, soil erosion process has to be clearly understood, and both organic carbon content and composition of SOM should be factored into the calculation. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Influence of smoking parameters on the concentration of polycyclic aromatic hydrocarbons (PAHs) in Danish smoked fish

    DEFF Research Database (Denmark)

    Duedahl-Olesen, Lene; Christensen, J. H.; Højgård, A.

    2010-01-01

    were also tested in a pilot plant study with smoked trout as a model fish. In addition to confirming that increased combustion temperatures and usage of common alder in comparison with beech increased Sigma PAH25, it was also revealed that the PAH concentration decreased in the order fish skin >> outer......A new method for the analysis of 25 polycyclic aromatic hydrocarbon (PAH) compounds in fish was developed, validated, and used for the quantification of PAHs in 180 industrially smoked fish products. The method included pressurized liquid extraction, gel-permeation chromatography (Bio-beads S-X3...... smoking, and for other fish species direct smoking leads to higher sigma PAH25 than indirect smoking. Also, the usage of common alder increases the PAH contamination compared with beech. The effects of smoking time, combustion temperatures, and two types of smoke-generating material on the Sigma PAH25...

  13. Verification of excess defense material

    International Nuclear Information System (INIS)

    Fearey, B.L.; Pilat, J.F.; Eccleston, G.W.; Nicholas, N.J.; Tape, J.W.

    1997-01-01

    The international community in the post-Cold War period has expressed an interest in the International Atomic Energy Agency (IAEA) using its expertise in support of the arms control and disarmament process in unprecedented ways. The pledges of the US and Russian presidents to place excess defense materials under some type of international inspections raises the prospect of using IAEA safeguards approaches for monitoring excess materials, which include both classified and unclassified materials. Although the IAEA has suggested the need to address inspections of both types of materials, the most troublesome and potentially difficult problems involve approaches to the inspection of classified materials. The key issue for placing classified nuclear components and materials under IAEA safeguards is the conflict between these traditional IAEA materials accounting procedures and the US classification laws and nonproliferation policy designed to prevent the disclosure of critical weapon-design information. Possible verification approaches to classified excess defense materials could be based on item accountancy, attributes measurements, and containment and surveillance. Such approaches are not wholly new; in fact, they are quite well established for certain unclassified materials. Such concepts may be applicable to classified items, but the precise approaches have yet to be identified, fully tested, or evaluated for technical and political feasibility, or for their possible acceptability in an international inspection regime. Substantial work remains in these areas. This paper examines many of the challenges presented by international inspections of classified materials

  14. Excess water dynamics in hydrotalcite: QENS study

    Indian Academy of Sciences (India)

    dynamics of excess water in hydrotalcite sample with varied content of excess water are reported. Translational motion of excess water can be best described by random transla- tional jump diffusion model. The observed increase in translational diffusivity with increase in the amount of excess water is attributed to the ...

  15. 34 CFR 300.16 - Excess costs.

    Science.gov (United States)

    2010-07-01

    ... 34 Education 2 2010-07-01 2010-07-01 false Excess costs. 300.16 Section 300.16 Education... DISABILITIES General Definitions Used in This Part § 300.16 Excess costs. Excess costs means those costs that... for an example of how excess costs must be calculated.) (Authority: 20 U.S.C. 1401(8)) ...

  16. Infrared Heaters

    Science.gov (United States)

    1979-01-01

    The heating units shown in the accompanying photos are Panelbloc infrared heaters, energy savers which burn little fuel in relation to their effective heat output. Produced by Bettcher Manufacturing Corporation, Cleveland, Ohio, Panelblocs are applicable to industrial or other facilities which have ceilings more than 12 feet high, such as those pictured: at left the Bare Hills Tennis Club, Baltimore, Maryland and at right, CVA Lincoln- Mercury, Gaithersburg, Maryland. The heaters are mounted high above the floor and they radiate infrared energy downward. Panelblocs do not waste energy by warming the surrounding air. Instead, they beam invisible heat rays directly to objects which absorb the radiation- people, floors, machinery and other plant equipment. All these objects in turn re-radiate the energy to the air. A key element in the Panelbloc design is a coating applied to the aluminized steel outer surface of the heater. This coating must be corrosion resistant at high temperatures and it must have high "emissivity"-the ability of a surface to emit radiant energy. The Bettcher company formerly used a porcelain coating, but it caused a production problem. Bettcher did not have the capability to apply the material in its own plant, so the heaters had to be shipped out of state for porcelainizing, which entailed extra cost. Bettcher sought a coating which could meet the specifications yet be applied in its own facilities. The company asked The Knowledge Availability Systems Center, Pittsburgh, Pennsylvania, a NASA Industrial Applications Center (IAC), for a search of NASA's files

  17. Developmental exposure to a complex PAH mixture causes persistent behavioral effects in naive Fundulus heteroclitus (killifish) but not in a population of PAH-adapted killifish.

    Science.gov (United States)

    Brown, D R; Bailey, J M; Oliveri, A N; Levin, E D; Di Giulio, R T

    2016-01-01

    Acute exposures to some individual polycyclic aromatic hydrocarbons (PAHs) and complex PAH mixtures are known to cause cardiac malformations and edema in the developing fish embryo. However, the heart is not the only organ impacted by developmental PAH exposure. The developing brain is also affected, resulting in lasting behavioral dysfunction. While acute exposures to some PAHs are teratogenically lethal in fish, little is known about the later life consequences of early life, lower dose subteratogenic PAH exposures. We sought to determine and characterize the long-term behavioral consequences of subteratogenic developmental PAH mixture exposure in both naive killifish and PAH-adapted killifish using sediment pore water derived from the Atlantic Wood Industries Superfund Site. Killifish offspring were embryonically treated with two low-level PAH mixture dilutions of Elizabeth River sediment extract (ERSE) (TPAH 5.04 μg/L and 50.4 μg/L) at 24h post fertilization. Following exposure, killifish were raised to larval, juvenile, and adult life stages and subjected to a series of behavioral tests including: a locomotor activity test (4 days post-hatch), a sensorimotor response tap/habituation test (3 months post hatch), and a novel tank diving and exploration test (3months post hatch). Killifish were also monitored for survival at 1, 2, and 5 months over 5-month rearing period. Developmental PAH exposure caused short-term as well as persistent behavioral impairments in naive killifish. In contrast, the PAH-adapted killifish did not show behavioral alterations following PAH exposure. PAH mixture exposure caused increased mortality in reference killifish over time; yet, the PAH-adapted killifish, while demonstrating long-term rearing mortality, had no significant changes in mortality associated with ERSE exposure. This study demonstrated that early embryonic exposure to PAH-contaminated sediment pore water caused long-term locomotor and behavioral alterations in

  18. Comparing PAH availability from manufactured gas plant soils and sediments with chemical and biological tests. 1. PAH release during water desorption and supercritical carbon dioxide extraction.

    Science.gov (United States)

    Hawthorne, Steven B; Poppendieck, Dustin G; Grabanski, Carol B; Loehr, Raymond C

    2002-11-15

    Soil and sediment samples from oil gas (OG) and coal gas (CG) manufactured gas plant (MGP) sites were selected to represent a range of PAH concentrations (150-40,000 mg/kg) and sample matrix compositions. Samples varied from vegetated soils to lampblack soot and had carbon contents from 3 to 87 wt %. SFE desorption (120 min) and water/XAD2 desorption (120 days) curves were determined and fit with a simple two-site model to determine the rapid-released fraction (F) for PAHs ranging from naphthalene to benzo[ghi]perylene. F values varied greatly among the samples, from ca. 10% to >90% for the two- and three-ring PAHs and from <1% to ca. 50% for the five- and six-ring PAHs. Release rates did not correlate with sample matrix characteristics including PAH concentrations, elemental composition (C, H, N, S), or "hard" and "softs" organic carbon, indicating that PAH release cannot easily be estimated on the basis of sample matrix composition. Fvalues for CG site samples obtained with SFE and water desorption agreed well (linear correlation coefficient, r2 = 0.87, slope = 0.93), but SFE yielded higher F values for the OG samples. These behaviors were attributed to the stronger ability of carbon dioxide than water to desorb PAHs from the highly aromatic (hard) carbon of the OG matrixes, while carbon dioxide and water showed similar abilities to desorb PAHs from the more polar (soft) carbon of the CG samples. The combined SFE and water desorption approaches should improve the understanding of PAH sequestration and release from contaminated soils and sediments and provide the basis for subsequent studies using the same samples to compare PAH release with PAH availability to earthworms.

  19. Distribution of PAHs and the PAH-degrading bacteria in the deep-sea sediments of the high-latitude Arctic Ocean

    Science.gov (United States)

    Dong, C.; Bai, X.; Sheng, H.; Jiao, L.; Zhou, H.; Shao, Z.

    2015-04-01

    Polycyclic aromatic hydrocarbons (PAHs) are common organic pollutants that can be transferred long distances and tend to accumulate in marine sediments. However, less is known regarding the distribution of PAHs and their natural bioattenuation in the open sea, especially the Arctic Ocean. In this report, sediment samples were collected at four sites from the Chukchi Plateau to the Makarov Basin in the summer of 2010. PAH compositions and total concentrations were examined with GC-MS. The concentrations of 16 EPA-priority PAHs varied from 2.0 to 41.6 ng g-1 dry weight and decreased with sediment depth and movement from the southern to the northern sites. Among the targeted PAHs, phenanthrene was relatively abundant in all sediments. The 16S rRNA gene of the total environmental DNA was analyzed with Illumina high-throughput sequencing (IHTS) to determine the diversity of bacteria involved in PAH degradation in situ. The potential degraders including Cycloclasticus, Pseudomonas, Halomonas, Pseudoalteromonas, Marinomonas, Bacillus, Dietzia, Colwellia, Acinetobacter, Alcanivorax, Salinisphaera and Shewanella, with Dietzia as the most abundant, occurred in all sediment samples. Meanwhile, enrichment with PAHs was initiated onboard and transferred to the laboratory for further enrichment and to obtain the degrading consortia. Most of the abovementioned bacteria in addition to Hahella, Oleispira, Oceanobacter and Hyphomonas occurred alternately as predominant members in the enrichment cultures from different sediments based on IHTS and PCR-DGGE analysis. To reconfirm their role in PAH degradation, 40 different bacteria were isolated and characterized, among which Cycloclasticus Pseudomonas showed the best degradation capability under low temperatures. Taken together, PAHs and PAH-degrading bacteria were widespread in the deep-sea sediments of the Arctic Ocean. We propose that bacteria of Cycloclasticus, Pseudomonas, Pseudoalteromonas, Halomonas, Marinomonas and Dietzia may

  20. Evaluation of hydrophobicity in PAH-contaminated soils during phytoremediation

    International Nuclear Information System (INIS)

    Cofield, Naressa; Banks, M. Katherine; Schwab, A. Paul

    2007-01-01

    The impact of recalcitrant organic compounds on soil hydrophobicity was evaluated in contaminated soil from a manufactured gas plant site following 12 months of phytoremediation. Significant reduction in soil wetting and water retention was observed in contaminated soil compared to an uncontaminated control. Phytoremediation was effective at reducing total PAHs by 69% with corresponding changes in soil classification from extremely hydrophobic (initial sample) to moderately-strongly hydrophobic (planted) and hydrophilic-very hydrophilic (unplanted) after 12 months. The greatest reduction in soil hydrophobicity was observed in the unplanted, unfertilized treatments that had the lowest removal rate of PAHs. The presence of plants may contribute to hydrophobicity in contaminated soil. - The presence of recalcitrant hydrophobic organic pollutants may enhance soil hydrophobicity

  1. Heavy metals, PAHs and toxicity in stormwater wet detention ponds

    DEFF Research Database (Denmark)

    Wium-Andersen, Tove; Nielsen, Asbjørn Haaning; Hvitved-Jacobsen, Thorkild

    2011-01-01

    Concentrations of 6 different heavy metals and total Polycyclic Aromatic Hydrocarbons (PAH) were determined in stormwater runoff and in the pond water of two Danish wet detention ponds. The pond water samples were analyzed for toxic effects, using the algae Selenastrum capricornutum as a test...... organism. Stormwater and pond water from a catchment with light industry showed high levels of heavy metals, especially zinc and copper. The pond water showed high toxic effects and copper were found to be the main toxicant. Additionally, a large part of the copper was suspected to be complex bound......, reducing the potential toxicity of the metal. Another catchment (residential) produced stormwater and pond water with moderate concentration of heavy metals. The pond water occasionally showed toxic effects but no correlation between heavy metals and toxicity was identified. PAHs concentrations were...

  2. Excess electron transport in cryoobjects

    International Nuclear Information System (INIS)

    Eshchenko, D.G.; Storchak, V.G.; Brewer, J.H.; Cottrell, S.P.; Cox, S.F.J.

    2003-01-01

    Experimental results on excess electron transport in solid and liquid phases of Ne, Ar, and solid N 2 -Ar mixture are presented and compared with those for He. Muon spin relaxation technique in frequently switching electric fields was used to study the phenomenon of delayed muonium formation: excess electrons liberated in the μ + ionization track converge upon the positive muons and form Mu (μ + e - ) atoms. This process is shown to be crucially dependent upon the electron's interaction with its environment (i.e., whether it occupies the conduction band or becomes localized in a bubble of tens of angstroms in radius) and upon its mobility in these states. The characteristic lengths involved are 10 -6 -10 -4 cm, the characteristic times range from nanoseconds to tens microseconds. Such a microscopic length scale sometimes enables the electron spend its entire free lifetime in a state which may not be detected by conventional macroscopic techniques. The electron transport processes are compared in: liquid and solid helium (where electron is localized in buble); liquid and solid neon (where electrons are delocalized in solid and the coexistence of localized and delocalized electrons states was found in liquid recently); liquid and solid argon (where electrons are delocalized in both phases); orientational glass systems (solid N 2 -Ar mixtures), where our results suggest that electrons are localized in orientational glass. This scaling from light to heavy rare gases enables us to reveal new features of excess electron localization on microscopic scale. Analysis of the experimental data makes it possible to formulate the following tendency of the muon end-of-track structure in condensed rare gases. The muon-self track interaction changes from the isolated pair (muon plus the nearest track electron) in helium to multi-pair (muon in the vicinity of tens track electrons and positive ions) in argon

  3. Removal of Heavy Metals and PAH in Retention Basins

    DEFF Research Database (Denmark)

    Larsen, Torben; Neerup-Jensen, Ole

    2004-01-01

    Solid seperation in retention basins is strongly non-linear and depends significantly on the flow rate and the settling characteristics of the particles. Accordingly the calculation of the annual loads of pollutants from storm overflows including basins is rather complex and time consuming...... in order to calculate annual loads of pollutants from urban catchments. The study cover Cd, Cu, Ni, Pb, Zn and PAH....

  4. Distribution Pattern of Polyaromatic Hydrocarbons (PAHs) in Soils in ...

    African Journals Online (AJOL)

    Distribution Pattern of Polyaromatic Hydrocarbons (PAHs) in Soils in the Vicinity of Fuel Stations in Abraka, Nigeria. ... (0.00191mg.kg-1). Investigation also reveals that all tested samples are contaminated, with mean values ranging between 0.000207±0.00026mg.kg-1 and 0.002123±0.00303mg.kg-1. Similarly, spearmen's ...

  5. Reduction of Ferrrihydrite and Akaganeite by Shewanella alga (PAH93)

    Science.gov (United States)

    Jung, M.; Kim, Y.; Lee, Y.; Kwon, K.; Roh, Y.

    2009-12-01

    Shewanella species are capable of oxidizing diverse organic acids coupled to reducing Fe(III) (oxy)hydroxides to crystalline Fe(II)-containing phases such as magnetite, siderite, and vivianite. The objective of this study was to examine reduction of ferrihydrite and akaganeite as the electron acceptors using various organic acids as the electron donors by Shewanella alga (PAH93) isolated from Yeosu, South Korea. Microbial reduction of akaganeite (40 mM) and ferrihydrite (40 mM) was examined using acetate (10 mM), glucose (10 mM), and lactate (10 mM) as electron donors at room temperature. Ferrozine method was used to analyze both water soluble and HCl soluble Fe(II) concentrations during the microbial Fe(III) reduction. XRD and TEM-EDX analyses were used to characterize biominerals formed by PAH93. PAH93 was completely reduced ferrihydrite to Fe(II), which transformed as siderite (FeCO3). PAH93 was oxidized acetate, glucose, and lactate coupled to reducing akaganeite to magnetite or green rust. Microbial reduction of ferrihydrite resulted in higher soluble Fe(II) concentration (446 - 498 mg/L) than the reduction of akaganeite (255 - 284 mg/L) within 6 days of incubation. For 21 days of incubation, souble Fe(II) concentration during akaganeite reduction (945 - 1316 mg/L) was higher than ferrihydrite reduction (120 - 738 mg/L). It may be attributed to the differences of crystallinity of the iron minerals used for microbial iron reduction. This study indicates types of the electron acceptors, ferrihydrite and akaganeite, affect Fe(II) reduction rate and types of the biotransformed minerals.

  6. Heterogeneous ozonation reactions of PAHs and fatty acid methyl esters in biodiesel particulate matter

    Science.gov (United States)

    Kasumba, John; Holmén, Britt A.

    2018-02-01

    Numerous studies have examined the oxidation of PAHs found in diesel particulate matter (PM) by ozone, but no studies have investigated the ozone oxidation of biodiesel exhaust PM. Fatty acid methyl esters (FAMEs), found in high abundance in biodiesel PM, can potentially alter the kinetics of the reactions between atmospheric oxidants such as ozone and particle-phase PAHs. In this study, the heterogeneous reactivity of 16 EPA PAHs upon 24 h exposure to 0.4 ppm ozone in the presence (PAH + FAMES) and absence (PAH-only) of FAMEs was investigated at room temperature and 50% relative humidity. The ozone-reactivity of the PAHs detected in 20% biodiesel (B20) exhaust PM was also investigated. In the absence of FAMEs, the pseudo-first order ozone reaction rate constant, kO 3 , of PAHs varied from 0.086 ± 0.030 hr-1 (chrysene) to 0.184 ± 0.078 hr-1 (anthracene). In the presence of FAMEs, kO 3 of the PAHs varied between 0.013 ± 0.012 hr-1 (benzo[b]fluoranthene) and 0.168 ± 0.028 hr-1 (benzo[a]pyrene), and with the exception of benzo[a]pyrene, the kO 3 of PAHs were 1.2-8 times lower compared to those obtained during the PAH-only ozone exposure. Only one PAH, benzo[a]pyrene (BaP), did not show a significant change in kO3 with addition of FAMEs. Phenanthrene, fluoranthene, and pyrene, the only PAHs detected in the B20 PM, had kO 3 values about 4 times lower in B20 PM than those obtained when spiked PAHs-only were exposed to ozone. The kO 3 values of phenanthrene and fluoranthene in the B20 PM were 2 times higher than rates obtained when the PAH mix was exposed to ozone in the presence of the FAMEs. In contrast, pyrene's kO 3 in the B20 PM was about 2 times lower than that obtained for the PAH + FAMEs exposure. Observed differences in PAH behavior demonstrate individual PAH heterogeneous reactivity with gas-phase ozone is sensitive to PAH (vapor pressure, solubility/sorption to matrix components, chemical reactivity) as well as substrate properties (PAH and O3 diffusivity

  7. Infrared radiation

    International Nuclear Information System (INIS)

    Moss, C.E.; Ellis, R.J.; Murray, W.E.; Parr, W.H.

    1989-01-01

    All people are exposed to IR radiation from sunlight, artificial light and radiant heating. Exposures to IR are quantified by irradiance and radiant exposure to characterize biological effects on the skin and cornea. However, near-IR exposure to the retina requires knowledge of the radiance of the IR source. With most IR sources in everyday use the health risks are considered minimal; only in certain high radiant work environments are individuals exposed to excessive levels. The interaction of IR radiation with biological tissues is mainly thermal. IR radiation may augment the biological response to other agents. The major health hazards are thermal injury to the eye and skin, including corneal burns from far-IR, heat stress, and retinal and lenticular injury from near-IR radiation. 59 refs, 13 figs, 2 tabs

  8. Processes controlling PAH leaching from two industrial sites

    Energy Technology Data Exchange (ETDEWEB)

    Jouannin, F. [Lab. d' Analyse Environmental des Procedes et des Systemes Industrielles, INSA de Lyon, Villeurbanne (France); Barna, R. [Lab. d' Analyse Environmental des Procedes et des Systemes Industrielles, INSA de Lyon, Villeurbanne (France)]|[Centre Energetique Environnement, Ecole des Mines d' Albi, Albi (France); Vernus, E. [POLDEN, INSA de Lyon, Villeurbanne (France)

    2002-07-01

    The persistence of hydrophobic organic pollutants like PAHs in weathered contaminated soils is a major impediment to their successful remediation. This persistence is caused by slow desorption and/or dissolution processes, resulting in small release rates of contaminants and therefore low concentrations in groundwater (Grathwohl, 1998). Laboratory experiments to assess the PAHs release are realised in stirred batch or with traditional percolation column. These two kind of tests show their limits in different cases like particulate disagregation by stirring or in the difficulty to control the soil/solution contact time in column experiments. Consequently a new experimental procedure is proposed, in which the compacted immobile soil is in contact with the eluate recycled in an inner loop. Two different soils containing HAPs (high and low polluted) were tested according to the new procedure. Different extracting solutions have been used: demineralised water, NaN{sub 3} and CaCl{sub 2} solutions. A water/methanol mixture has also been used to increase pollutants release by increasing their solubility. This is a first step in the elaboration of an assessment methodology of the PAHs mobility in soils. (orig.)

  9. Extraction agents for the removal of polycyclic aromatic hydrocarbons (PAHs) from soil in soil washing technologies

    International Nuclear Information System (INIS)

    Lau, Ee Von; Gan, Suyin; Ng, Hoon Kiat; Poh, Phaik Eong

    2014-01-01

    Polycyclic aromatic hydrocarbons (PAHs) in soil have been recognised as a serious health and environmental issue due to their carcinogenic, mutagenic and teratogenic properties. One of the commonly employed soil remediation techniques to clean up such contamination is soil washing or solvent extraction. The main factor which governs the efficiency of this process is the solubility of PAHs in the extraction agent. Past field-scale soil washing treatments for PAH-contaminated soil have mainly employed organic solvents or water which is either toxic and costly or inefficient in removing higher molecular weight PAHs. Thus, the present article aims to provide a review and discussion of the alternative extraction agents that have been studied, including surfactants, biosurfactants, microemulsions, natural surfactants, cyclodextrins, vegetable oil and solution with solid phase particles. These extraction agents have been found to remove PAHs from soil at percentages ranging from 47 to 100% for various PAHs. -- Highlights: • The alternative and advancement in extraction agents to remove PAHs from soil using soil washing technology is summarised. • The soil regulations for PAH level in various countries are summarized for reference to researchers. • The concentration levels of PAHs in soil at present and the need for soil remediation is presented. -- The efficiency of the extraction agent plays a significant role in soil washing of PAH-contaminated soil

  10. [The mutation analysis of PAH gene and prenatal diagnosis in classical phenylketonuria family].

    Science.gov (United States)

    Yan, Yousheng; Hao, Shengju; Yao, Fengxia; Sun, Qingmei; Zheng, Lei; Zhang, Qinghua; Zhang, Chuan; Yang, Tao; Huang, Shangzhi

    2014-12-01

    To characterize the mutation spectrum of phenylalanine hydroxylase (PAH) gene and perform prenatal diagnosis for families with classical phenylketonuria. By stratified sequencing, mutations were detected in the exons and flaking introns of PAH gene of 44 families with classical phenylketonuria. 47 fetuses were diagnosed by combined sequencing with linkage analysis of three common short tandem repeats (STR) (PAH-STR, PAH-26 and PAH-32) in the PAH gene. Thirty-one types of mutations were identified. A total of 84 mutations were identified in 88 alleles (95.45%), in which the most common mutation have been R243Q (21.59%), EX6-96A>G (6.82%), IVS4-1G>A (5.86%) and IVS7+2T>A (5.86%). Most mutations were found in exons 3, 5, 6, 7, 11 and 12. The polymorphism information content (PIC) of these three STR markers was 0.71 (PAH-STR), 0.48 (PAH-26) and 0.40 (PAH-32), respectively. Prenatal diagnosis was performed successfully with the combined method in 47 fetuses of 44 classical phenylketonuria families. Among them, 11 (23.4%) were diagnosed as affected, 24 (51.1%) as carriers, and 12 (25.5%) as unaffected. Prenatal diagnosis can be achieved efficiently and accurately by stratified sequencing of PAH gene and linkage analysis of STR for classical phenylketonuria families.

  11. Biomonitoring seasonal variation of urban air polycyclic aromatic hydrocarbons (PAHs) using Ficus benghalensis leaves

    International Nuclear Information System (INIS)

    Prajapati, Santosh Kumar; Tripathi, B.D.

    2008-01-01

    Temporal and seasonal variations of polycyclic aromatic hydrocarbons (PAHs) concentrations in leaves of Ficus benghalensis were investigated in Varanasi city (India). Leaf samples were collected from six sites from urban area of Varanasi and from a control site. PAH extraction was done by sonication in dichloromethane-acetone and quantification by GC-MS. In January total leaf PAHs concentrations at all the urban sites were twice higher as compared to other season's viz. summer and rainy. In contrast, at the control site leaf PAHs concentrations showed lower values than urban sites. The maximum concentrations of total PAHs in winter were due to the medium molecular weight PAHs which increases with respect to both low and high molecular weight PAHs. The temporal variation of medium molecular weight PAHs was similar both at the urban and remote sites. These results support biomonitoring ability of Ficus benghalensis leaves to temporal variations in PAHs contamination. - Biomonitoring PAHs in atmosphere using F. benghalensis leaves for its temporal and seasonal variation is cost effective as well as easier

  12. The economic burden of pulmonary arterial hypertension (PAH) in the US on payers and patients.

    Science.gov (United States)

    Sikirica, Mirko; Iorga, Serban R; Bancroft, Tim; Potash, Jesse

    2014-12-24

    Pulmonary arterial hypertension (PAH) is a rare condition that can ultimately lead to right heart failure and death. In this study we estimated the health care costs and resource utilization associated with PAH in a large US managed care health plan. Subjects with claims-based evidence of PAH from 1/1/2004 to 6/30/2010 (identification period) were selected. To be included in the final PAH study sample, subjects were required to have ≥2 claims with a primary PH diagnosis; ≥2 claims with a PAH related-diagnosis (connective tissue diseases, congenital heart diseases, portal hypertension); and ≥1 claim with evidence of a PAH-indicated medication. The earliest date of a claim with evidence of PAH-indicated medication during the identification period was set as the index date. Health care costs and resource utilization were compared between an annualized baseline period and a 12 month follow-up period. 504 PAH subjects were selected for the final study cohort. Estimated average total health care costs were approximately 16% lower in the follow-up period compared to the baseline period (follow-up costs = $98,243 [SD = 110,615] vs. baseline costs = $116,681 [SD = 368,094], p PAH had substantively high health care costs. Medical costs appeared to decrease following PAH medication use, but with a concomitant increase in pharmacy costs.

  13. Current Approaches to the Treatment of Systemic-Sclerosis-Associated Pulmonary Arterial Hypertension (SSc-PAH).

    Science.gov (United States)

    Sobanski, Vincent; Launay, David; Hachulla, Eric; Humbert, Marc

    2016-02-01

    Pulmonary arterial hypertension (PAH) is a severe condition causing significant morbidity and mortality in patients with systemic sclerosis (SSc). Despite the use of specific treatments, SSc-PAH survival remains poorer than in idiopathic PAH (IPAH). Recent therapeutic advances in PAH show a lower magnitude of response in SSc-PAH and a higher risk of adverse events, as compared to IPAH. The multifaceted underlying mechanisms and the multisystem nature of SSc probably explain part of the worse outcomes in SSc-PAH compared to IPAH. This review describes the current management of SSc-PAH with an emphasis on the impact of the different organ involvements in the prognosis and treatment response. An earlier detection of PAH and a better characterization of the clinical phenotypes of SSc-PAH are warranted in clinical practice and future trials. Determinants of prognosis, surrogate markers of clinical improvement or worsening, and relevance of the common endpoints used in clinical trials should be evaluated in this specific population. A multidisciplinary approach in expert referral centers is mandatory for SSc-PAH management.

  14. Senyawa polisiklik aromatik hidrokarbon (PAH dalam air laut di Teluk Jakarta

    Directory of Open Access Journals (Sweden)

    Edward .

    2014-01-01

    Full Text Available Research on polycyclic aromatic hydrocarbons (pahs compound at Jakarta Bay seawater were carried out on July 2011. The objectives of this research were to measure the concentration of total polycyclic aromatic hydrocarbons (PAH compound, concentration of individual PAH compound, and to identify sources of PAH compound in seawater. PAH compound concentration was measured by Gas Chromatography (Gas Chromatography-Flame Ionization Detector and sources of polycyclic aromatic hydrocarbons compound were identified by diagnostic ratio analysis. The results show that the concentration of PAH compound in the middle of Jakarta Bay was higher compared to the west and the east. In the west and middle of Jakarta Bay, it is found that 11 PAH types, and 10 types in the east. Individual PAH compound dominated by high moleculer weight of PAH Benzo(aAnthracene, Chrysene, Benzo(bFluoranthene, Benzo(aPyrene, dan Indeno(123-cd Pyrene. The results of PAH compound ratio individual analysis showed that polycyclic aromatic hydrocarbons compound at Jakarta Bay seawater came from oil spill and incomplete combustion mixture of organic material such as wood, grass, fuel oil, and fuel industry combustion activity.

  15. Generation and distribution of PAHs in the process of medical waste incineration

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ying, E-mail: echochen327@163.com [School of Environment, Tsinghua University, Beijing 100084 (China); National Center of Solid Waste Management, Ministry of Environmental Protection, Beijing 100029 (China); Zhao, Rongzhi [Civil and Environmental Engineering School, University of Science and Technology Beijing, Beijing 100083 (China); Xue, Jun [National Center of Solid Waste Management, Ministry of Environmental Protection, Beijing 100029 (China); Li, Jinhui, E-mail: jinhui@tsinghua.edu.cn [State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084 (China)

    2013-05-15

    Highlights: ► PAHs generation and distribution features of medical waste incineration are studied. ► More PAHs were found in fly ash than that in bottom ash. ► The highest proportion of PAHs consisted of the seven most carcinogenic ones. ► Increase of free oxygen molecule and burning temperature promote PAHs degradation. ► There is a moderate positive correlation between total PCDD/Fs and total PAHs. - Abstract: After the deadly earthquake on May 12, 2008 in Wenchuan county of China, several different incineration approaches were used for medical waste disposal. This paper investigates the generation properties of polycyclic aromatic hydrocarbons (PAHs) during the incineration. Samples were collected from the bottom ash in an open burning slash site, surface soil at the open burning site, bottom ash from a simple incinerator, bottom ash generated from the municipal solid waste (MSW) incinerator used for medical waste disposal, and bottom ash and fly ash from an incinerator exclusively used for medical waste. The species of PAHs were analyzed, and the toxicity equivalency quantities (TEQs) of samples calculated. Analysis results indicate that the content of total PAHs in fly ash was 1.8 × 10{sup 3} times higher than that in bottom ash, and that the strongly carcinogenic PAHs with four or more rings accumulated sensitively in fly ash. The test results of samples gathered from open burning site demonstrate that Acenaphthylene (ACY), Acenaphthene (ACE), Fluorene (FLU), Phenanthrene (PHE), Anthracene (ANT) and other PAHs were inclined to migrate into surrounding environment along air and surface watershed corridors, while 4- to 6-ring PAHs accumulated more likely in soil. Being consistent with other studies, it has also been confirmed that increases in both free oxygen molecules and combustion temperatures could promote the decomposition of polycyclic PAHs. In addition, without the influence of combustion conditions, there is a positive correlation between

  16. Spatial and temporal distribution of polycyclic aromatic hydrocarbons (PAHs) in the atmosphere of Xiamen, China

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Jinping [Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021 (China); Guangdong Environmental Monitoring Centre, Guangzhou 510308 (China); Zhang, Fuwang; Xu, Lingling [Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021 (China); Graduate School of Chinese Academy of Sciences, Beijing 100049 (China); Chen, Jinsheng, E-mail: jschen@iue.ac.cn [Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021 (China); Xu, Ya [Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021 (China); Graduate School of Chinese Academy of Sciences, Beijing 100049 (China)

    2011-11-15

    An intensive sampling program was conducted from October 2008 to September 2009 at the five different environmental sites in Xiamen, Fujian Province, to study the spatial and temporal characteristics of Polycyclic Aromatic Hydrocarbons (PAHs) in the gaseous and particulate phase, respectively. The PAHs concentrations at different sites were quite distinct during four seasons. The average concentrations of PAHs in winter were about 8.4 times higher than those in spring, and the concentrations of background were 0.56 times lower than those of industrial area. In addition, the higher temperature in summer affected the particle/gas partitioning of PAHs and led to the higher concentrations of gaseous PAHs. Diagnostic ratios of PAHs, which were employed to indicate the primary sources of PAHs in Xiamen, showed that the traffic vehicle exhaust was the largest contributor and the primary source for PAHs in Xiamen, especially in urban area; while the stationary combustion processes, such as petrochemical factories and power plants, were mainly responsible for PAHs sources in the industrial areas. The health risk of PAHs in the particulate phase was higher than those of the gaseous phase at the five sampling sites. The average toxic equivalent (BaP{sub eq}) of the benzo[a]pyrene values for PAHs were 0.14, 0.32, 1.38 and 3.59 ng m{sup -3} in spring, summer, autumn and winter, respectively. Furthermore, the results of average BaP{sub eq} in all four seasons indicated that the health risks of particulate PAHs were higher than those of the gaseous PAHs at different sampling sites.

  17. Using slow-release permanganate candles to remediate PAH-contaminated water.

    Science.gov (United States)

    Rauscher, Lindy; Sakulthaew, Chainarong; Comfort, Steve

    2012-11-30

    Surface waters impacted by urban runoff in metropolitan areas are becoming increasingly contaminated with polycyclic aromatic hydrocarbons (PAHs). Slow-release oxidant candles (paraffin-KMnO(4)) are a relatively new technology being used to treat contaminated groundwater and could potentially be used to treat urban runoff. Given that these candles only release permanganate when submerged, the ephemeral nature of runoff events would influence when the permanganate is released for treating PAHs. Our objective was to determine if slow-release permanganate candles could be used to degrade and mineralize PAHs. Batch experiments quantified PAH degradation rates in the presence of the oxidant candles. Results showed most of the 16 PAHs tested were degraded within 2-4 h. Using (14)C-labled phenanthrene and benzo(a)pyrene, we demonstrated that the wax matrix of the candle initially adsorbs the PAH, but then releases the PAH back into solution as transformed, more water soluble products. While permanganate was unable to mineralize the PAHs (i.e., convert to CO(2)), we found that the permanganate-treated PAHs were much more biodegradable in soil microcosms. To test the concept of using candles to treat PAHs in multiple runoff events, we used a flow-through system where urban runoff water was pumped over a miniature candle in repetitive wet-dry, 24-h cycles. Results showed that the candle was robust in removing PAHs by repeatedly releasing permanganate and degrading the PAHs. These results provide proof-of-concept that permanganate candles could potentially provide a low-cost, low-maintenance approach to remediating PAH-contaminated water. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. Generation and distribution of PAHs in the process of medical waste incineration

    International Nuclear Information System (INIS)

    Chen, Ying; Zhao, Rongzhi; Xue, Jun; Li, Jinhui

    2013-01-01

    Highlights: ► PAHs generation and distribution features of medical waste incineration are studied. ► More PAHs were found in fly ash than that in bottom ash. ► The highest proportion of PAHs consisted of the seven most carcinogenic ones. ► Increase of free oxygen molecule and burning temperature promote PAHs degradation. ► There is a moderate positive correlation between total PCDD/Fs and total PAHs. - Abstract: After the deadly earthquake on May 12, 2008 in Wenchuan county of China, several different incineration approaches were used for medical waste disposal. This paper investigates the generation properties of polycyclic aromatic hydrocarbons (PAHs) during the incineration. Samples were collected from the bottom ash in an open burning slash site, surface soil at the open burning site, bottom ash from a simple incinerator, bottom ash generated from the municipal solid waste (MSW) incinerator used for medical waste disposal, and bottom ash and fly ash from an incinerator exclusively used for medical waste. The species of PAHs were analyzed, and the toxicity equivalency quantities (TEQs) of samples calculated. Analysis results indicate that the content of total PAHs in fly ash was 1.8 × 10 3 times higher than that in bottom ash, and that the strongly carcinogenic PAHs with four or more rings accumulated sensitively in fly ash. The test results of samples gathered from open burning site demonstrate that Acenaphthylene (ACY), Acenaphthene (ACE), Fluorene (FLU), Phenanthrene (PHE), Anthracene (ANT) and other PAHs were inclined to migrate into surrounding environment along air and surface watershed corridors, while 4- to 6-ring PAHs accumulated more likely in soil. Being consistent with other studies, it has also been confirmed that increases in both free oxygen molecules and combustion temperatures could promote the decomposition of polycyclic PAHs. In addition, without the influence of combustion conditions, there is a positive correlation between total

  19. Characteristics of PAHs from deep-frying and frying cooking fumes.

    Science.gov (United States)

    Yao, Zhiliang; Li, Jing; Wu, Bobo; Hao, Xuewei; Yin, Yong; Jiang, Xi

    2015-10-01

    Cooking fumes are an important indoor source of polycyclic aromatic hydrocarbons (PAHs). Because indoor pollution has a more substantial impact on human health than outdoor pollution, PAHs from cooking fumes have drawn considerable attention. In this study, 16 PAHs emitted through deep-frying and frying methods using rapeseed, soybean, peanut, and olive oil were examined under a laboratory fume hood. Controlled experiments were conducted to collect gas- and particulate-phase PAHs emitted from the cooking oil fumes, and PAH concentrations were quantified via high-performance liquid chromatography (HPLC). The results show that deep-frying methods generate more PAHs and benzo[a]pyrene (B[a]P) (1.3 and 10.9 times, respectively) because they consume greater volumes of edible oil and involve higher oil temperatures relative to those of frying methods. In addition, the total B[a]Peq concentration of deep-frying is 2.2-fold larger than that of frying. Regarding the four types of edible oils studied, rapeseed oil produced more PAH emission than the other three oil varieties. For all of the cooking tests, three- and four-ringed PAHs were the main PAH components regardless of the food and oil used. Concerning the PAH partition between gas and particulate phase, the gaseous compounds accounted for 59-96 % of the total. Meanwhile, the particulate fraction was richer of high molecular weight PAHs (five-six rings). Deep-frying and frying were confirmed as important sources of PAH pollution in internal environments. The results of this study provide additional insights into the polluting features of PAHs produced via cooking activities in indoor environments.

  20. Experimental increase in availability of a PAH complex organic contamination from an aged contaminated soil: Consequences on biodegradation

    International Nuclear Information System (INIS)

    Cébron, Aurélie; Faure, Pierre; Lorgeoux, Catherine; Ouvrard, Stéphanie; Leyval, Corinne

    2013-01-01

    Although high PAH content and detection of PAH-degraders, the PAH biodegradation is limited in aged-contaminated soils due to low PAH availability (i.e., 1%). Here, we tried to experimentally increase the soil PAH availability by keeping both soil properties and contamination composition. Organic extract was first removed and then re-incorporated in the raw soil as fresh contaminants. Though drastic, this procedure only allowed a 6-time increase in the PAH availability suggesting that the organic constituents more than ageing were responsible for low availability. In the re-contaminated soil, the mineralization rate was twice more important, the proportion of 5–6 cycles PAH was higher indicating a preferential degradation of lower molecular weight PAH. The extraction treatment induced bacterial and fungal community structures modifications, Pseudomonas and Fusarium solani species were favoured, and the relative quantity of fungi increased. In re-contaminated soil the percentage of PAH-dioxygenase gene increased, with 10 times more Gram negative representatives. -- Highlights: ► Re-incorporation of soil organic extract increased 6-times the PAH availability. ► Complexity of organic contamination is the main driver of PAH availability. ► Biodegradation of PAH with less than 5-cycles increased with increasing PAH availability. ► Pseudomonas and Fusarium species are favoured when PAH availability increased. -- More than ageing, the complexity of organic contamination is the main driver of PAH availability

  1. Excess electron transport in cryoobjects

    CERN Document Server

    Eshchenko, D G; Brewer, J H; Cottrell, S P; Cox, S F J

    2003-01-01

    Experimental results on excess electron transport in solid and liquid phases of Ne, Ar, and solid N sub 2 -Ar mixture are presented and compared with those for He. Muon spin relaxation technique in frequently switching electric fields was used to study the phenomenon of delayed muonium formation: excess electrons liberated in the mu sup + ionization track converge upon the positive muons and form Mu (mu sup + e sup -) atoms. This process is shown to be crucially dependent upon the electron's interaction with its environment (i.e., whether it occupies the conduction band or becomes localized in a bubble of tens of angstroms in radius) and upon its mobility in these states. The characteristic lengths involved are 10 sup - sup 6 -10 sup - sup 4 cm, the characteristic times range from nanoseconds to tens microseconds. Such a microscopic length scale sometimes enables the electron spend its entire free lifetime in a state which may not be detected by conventional macroscopic techniques. The electron transport proc...

  2. Biodiesel emissions profile in modern diesel vehicles. Part 2: Effect of biodiesel origin on carbonyl, PAH, nitro-PAH and oxy-PAH emissions.

    Science.gov (United States)

    Karavalakis, Georgios; Boutsika, Vasiliki; Stournas, Stamoulis; Bakeas, Evangelos

    2011-01-15

    In the present study, the effects of different biodiesel blends on the unregulated emissions of a Euro 4 compliant passenger car were examined. Two fresh and two oxidized biodiesel fuels of different source materials were blended with an ultra low sulphur automotive diesel fuel at proportions of 10, 20, and 30% v/v. Emission measurements were conducted on a chassis dynamometer with a constant volume sampling (CVS) technique, over the New European Driving Cycle (NEDC) and the Artemis driving cycles. The experimental results revealed that the addition of biodiesel led to important increases in most carbonyl compounds. Sharp increases were observed with the use of the oxidized biodiesel blends, especially those prepared from used frying oil methyl esters. Similar to carbonyl emissions, most PAH compounds increased with the addition of the oxidized biodiesel blends. It can be assumed that the presence of polymerization products and cyclic acids, along with the degree of unsaturation were the main factors that influenced carbonyl and PAH emissions profile. Copyright © 2010 Elsevier B.V. All rights reserved.

  3. Mobile sources of polycyclic aromatic hydrocarbons (PAH) and nitro-PAH: Results of samples collected in a roadway tunnel

    International Nuclear Information System (INIS)

    Benner, B.A. Jr.; Gordon, G.E.; Wise, S.A.

    1987-01-01

    A recent review article emphasized the need for further characterizations of the carbonaceous fraction of mobile source emissions, particularly with the impending removal of lead alkyl octane boosters and bromine-containing lead scavengers from regular leaded gasolines. The lead and bromine emitted from the combustion of these fuels have been used as tracers of mobile source emissions for a number of years. Single vehicle emission studies have shed light on the relationship between engine operating parameters and the chemical characteristics of the emissions but they are not suitable for use in source apportionment studies which require emission data from a large number of different vehicles. Air particulate samples collected near a busy highway or in a roadway tunnel would be more appropriate for use in estimating the mobile source contribution of organic compounds to a region. Suspended particle samples collected in a heavily-travelled roadway tunnel (Baltimore Harbor Tunnel, Baltimore, Maryland) were characterized for polycyclic aromatic hydrocarbons (PAH) and some nitro-PAH by gas and liquid chromatographic techniques. These samples included those collected on Teflon filters and on glass fiber filters for investigating any differences in samples collected on an inert (Teflon) and more reactive (glass-fiber) medium. All samples collected on Teflon were backed-up with polyurethane foam plugs (PUF) which trapped any inherent vapor-phase PAH as well as any compounds ''blown-off'' the particles during collection

  4. Using slow-release permanganate candles to remediate PAH-contaminated water

    Energy Technology Data Exchange (ETDEWEB)

    Rauscher, Lindy, E-mail: purplerauscher@neb.rr.com [School of Natural Resources, University of Nebraska, Lincoln, NE 68583-0915 (United States); Sakulthaew, Chainarong, E-mail: chainarong@huskers.unl.edu [School of Natural Resources, University of Nebraska, Lincoln, NE 68583-0915 (United States); Department of Veterinary Technology, Kasetsart University, Bangkok 10900 (Thailand); Comfort, Steve, E-mail: scomfort1@unl.edu [School of Natural Resources, University of Nebraska, Lincoln, NE 68583-0915 (United States)

    2012-11-30

    Highlights: Black-Right-Pointing-Pointer We quantified the efficacy of slow-release permanganate-paraffin candles to degrade and mineralize PAHs. Black-Right-Pointing-Pointer {sup 14}C-labeled PAHs were used to quantify both adsorption and transformation. Black-Right-Pointing-Pointer Permanganate-treated PAHs were more biodegradable in soil microcosms. Black-Right-Pointing-Pointer A flow-through candle system was used to quantify PAH removal in urban runoff. - Abstract: Surface waters impacted by urban runoff in metropolitan areas are becoming increasingly contaminated with polycyclic aromatic hydrocarbons (PAHs). Slow-release oxidant candles (paraffin-KMnO{sub 4}) are a relatively new technology being used to treat contaminated groundwater and could potentially be used to treat urban runoff. Given that these candles only release permanganate when submerged, the ephemeral nature of runoff events would influence when the permanganate is released for treating PAHs. Our objective was to determine if slow-release permanganate candles could be used to degrade and mineralize PAHs. Batch experiments quantified PAH degradation rates in the presence of the oxidant candles. Results showed most of the 16 PAHs tested were degraded within 2-4 h. Using {sup 14}C-labled phenanthrene and benzo(a)pyrene, we demonstrated that the wax matrix of the candle initially adsorbs the PAH, but then releases the PAH back into solution as transformed, more water soluble products. While permanganate was unable to mineralize the PAHs (i.e., convert to CO{sub 2}), we found that the permanganate-treated PAHs were much more biodegradable in soil microcosms. To test the concept of using candles to treat PAHs in multiple runoff events, we used a flow-through system where urban runoff water was pumped over a miniature candle in repetitive wet-dry, 24-h cycles. Results showed that the candle was robust in removing PAHs by repeatedly releasing permanganate and degrading the PAHs. These results provide

  5. Using slow-release permanganate candles to remediate PAH-contaminated water

    International Nuclear Information System (INIS)

    Rauscher, Lindy; Sakulthaew, Chainarong; Comfort, Steve

    2012-01-01

    Highlights: ► We quantified the efficacy of slow-release permanganate-paraffin candles to degrade and mineralize PAHs. ► 14 C-labeled PAHs were used to quantify both adsorption and transformation. ► Permanganate-treated PAHs were more biodegradable in soil microcosms. ► A flow-through candle system was used to quantify PAH removal in urban runoff. - Abstract: Surface waters impacted by urban runoff in metropolitan areas are becoming increasingly contaminated with polycyclic aromatic hydrocarbons (PAHs). Slow-release oxidant candles (paraffin–KMnO 4 ) are a relatively new technology being used to treat contaminated groundwater and could potentially be used to treat urban runoff. Given that these candles only release permanganate when submerged, the ephemeral nature of runoff events would influence when the permanganate is released for treating PAHs. Our objective was to determine if slow-release permanganate candles could be used to degrade and mineralize PAHs. Batch experiments quantified PAH degradation rates in the presence of the oxidant candles. Results showed most of the 16 PAHs tested were degraded within 2–4 h. Using 14 C-labled phenanthrene and benzo(a)pyrene, we demonstrated that the wax matrix of the candle initially adsorbs the PAH, but then releases the PAH back into solution as transformed, more water soluble products. While permanganate was unable to mineralize the PAHs (i.e., convert to CO 2 ), we found that the permanganate-treated PAHs were much more biodegradable in soil microcosms. To test the concept of using candles to treat PAHs in multiple runoff events, we used a flow-through system where urban runoff water was pumped over a miniature candle in repetitive wet–dry, 24-h cycles. Results showed that the candle was robust in removing PAHs by repeatedly releasing permanganate and degrading the PAHs. These results provide proof-of-concept that permanganate candles could potentially provide a low-cost, low-maintenance approach to

  6. Infrared galaxies in the IRAS minisurvey

    Science.gov (United States)

    Soifer, B. T.; Neugebauer, G.; Rowan-Robinson, M.; Clegg, P. E.; Emerson, J. P.; Houck, J. R.; De Jong, T.; Aumann, H. H.; Beichman, C. A.; Boggess, N.

    1984-01-01

    A total of 86 galaxies have been detected at 60 microns in the high galactic latitude portion of the IRAS minisurvey. The surface density of detected galaxies with flux densities greater than 0.5 Jy is 0.25 sq deg. Virtually all the galaxies detected are spiral galaxies and have an infrared to blue luminosity ratio ranging from 50 to 0.5. For the infrared-selected sample, no obvious correlation exists between infrared excess and color temperature. The infrared flux from 10 to 100 microns contributes approximately 5 percent of the blue luminosity for galaxies in the magnitude range 14 less than m(pg) less than 18 mag. The fraction of interacting galaxies is between one-eighth and one-fourth of the sample.

  7. The Role of Human Aldo-Keto Reductases (AKRs in the Metabolic Activation and Detoxication of Polycyclic Aromatic Hydrocarbons: Interconversion of PAH-catechols and PAH o-Quinones

    Directory of Open Access Journals (Sweden)

    Li eZhang

    2012-11-01

    Full Text Available Polycyclic aromatic hydrocarbons (PAH are ubiquitous environmental pollutants. They are procarcinogens requiring metabolic activation to elicit their deleterious effects. Aldo-keto reductases (AKR catalyze the oxidation of proximate carcinogenic PAH trans-dihydrodiols to yield electrophilic and redox-active PAH o-quiniones. AKRs are also found to be capable of reducing PAH o-quinones to form PAH catechols. The interconversion of o-quinones and catechols results in the redox cycling of PAH o-quinones to give rise to the generation of reactive oxygen species and subsequent oxidative DNA damage. On the other hand, PAH catechols can be intercepted through phase II metabolism by which PAH o-quinones could be detoxified and eliminated. The aim of the present review is to summarize the role of human AKRs in the metabolic activation/detoxication of PAH and the relevance of phase II conjugation reactions to human lung carcinogenesis.

  8. 1-hydroxypyrene as a biomarker of PAH exposure in the marine invertebrates N. diversicolor

    DEFF Research Database (Denmark)

    Tairova, Zhanna; Giessing, Anders; Hansen, Rikke

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous, persistent and toxic contaminants in the marine environment. Uptake of PAHs by marine deposit-feeding invertebrates can be determined by screening for PAH-derived metabolites. Methods for detection and quantification of PAH metabolites may...... invertebrates is on the other hand practically non-existing. The present study investigated formation of pyrene metabolites in the marine polychaete Nereis diversicolor, with special attention given to the detection of 1-hydroxypyrene. 1-hydroxypyrene was identified in tissues of Nereis diversicolor exposed...... this context the usefulness of SFS for identification and quantification was explored. Considering the complex composition of environmental PAH pollution, before the 1-hydoxypyrene in tissues of exposed marine invertebrates can be regarded as a suitable biomarker for assessing total PAH exposure...

  9. Phytoremediation of polycyclic aromatic hydrocarbons (PAH) by cv. Crioula: A Brazilian alfalfa cultivar.

    Science.gov (United States)

    Alves, Wilber S; Manoel, Evelin A; Santos, Noemi S; Nunes, Rosane O; Domiciano, Giselli C; Soares, Marcia R

    2018-07-03

    This work aimed to evaluate the phytoremediation capacity of the alfalfa cultivar Crioula in soils contaminated with polycyclic aromatic hydrocarbons (PAHs), primary pollutants with mutagenic and carcinogenic potential. Alfalfa was grown from seed for 40 days on soil amended with anthracene, pyrene, and phenanthrene. Soil and plant tissue was collected for biometric assay, dry mass analysis, and PAH analysis by liquid chromatography. Increased total PAH concentration was associated with decreases in plant biomass, height, and internode length. The Crioula cultivar had a satisfactory phytoremediation effect, reducing total PAH concentration (300 ppm) in the experimental soil by 85% in 20 days, and by more than 95% in 40 days. The PAH showed a tendency to be removed in the temporal order: phenanthrene before pyrene before anthracene, and the removal ratio was influenced by the initial soil concentration of each PAH.

  10. PAH dissipation in a contaminated river sediment under oxic and anoxic conditions

    International Nuclear Information System (INIS)

    Quantin, C.; Joner, E.J.; Portal, J.M.; Berthelin, J.

    2005-01-01

    A batch experiment was conducted to compare PAH degradation in a polluted river sediment under aerobic and anaerobic conditions, and to investigate whether input of fresh organic material (cellulose) could enhance such degradation. All measurements were checked against abiotic control treatments to exclude artifacts of sample preparation and non-biological processes like aging. Three- and four-ring PAHs could be degraded by the indigenous microbial community under aerobic conditions, but anaerobic metabolism based on iron and sulphate reduction was not coupled with PAH degradation of even the simplest 3-ring compounds like phenanthrene. Cellulose addition stimulated both aerobic and anaerobic respiration, but had no effect on PAH dissipation. We conclude that natural attenuation of PAHs in polluted river sediments under anaerobic conditions is exceedingly slow. Dredging and biodegradation on land under aerobic conditions would be required to safely remediate and restore polluted sites. - Natural attenuation of PAHs under anaerobic conditions is exceedingly slow

  11. Source identification of Polycyclic Aromatic Hydrocarbons (PAHs in the urban environment of İstanbul

    Directory of Open Access Journals (Sweden)

    Günay Kural

    2018-04-01

    Full Text Available In this study, İstanbul-Tuzla Region atmosphere is selected as the working area because of this region contains shipyards and shipyard-related side product industries. To examine the PAHs as atmospheric inputs, 46 ambient air samples were collected in Tuzla region of Istanbul, Turkey at 2010. The sample collection was carried out as monthly. Additionally, the volume of the air was drawn and meteorological data recorded. The PAH concentrations were classified as hot and cold season samples. Due to the particle-bond character of PAHs and condensation in cold, the high concentrations were encountered in winter months. Monthly average total PAH concentrations fluctuated between 7.4 ng m-3 (in March-0.05 ng m-3 (in August. The concentrations of total PAHs in cold season were almost hundred times higher than those in hot season. The fossil fuel (gasoline and diesel fuel combustion was found to be the main source of PAHs.

  12. Study of PAH emission from the solid fuels combustion in residential furnaces

    International Nuclear Information System (INIS)

    Kakareka, Sergey V.; Kukharchyk, Tamara I.; Khomich, Valery S.

    2005-01-01

    The procedure for and results of a test study of polycyclic aromatic hydrocarbon (PAH) emission from a few types of solid fuels combustion in residential furnaces of various designs typical for Belarus are discussed. Greatest levels of PAH emission were detected from domestic wastes and wood waste combustion. Lowest levels of PAH emission are from peat briquette combustion. It was found that PAH concentration in off-gases from firewood combustion also varies significantly depending on the type of wood: the highest values of PAH are typical for waste gases from birch firewood combustion in comparison with pine firewood combustion. Draft PAH emission factors are proposed with intended application for emission inventory of such installations

  13. Distribution and Source of Sedimentary Polycyclic Aromatic Hydrocarbon (PAHs in River Sediment of Jakarta

    Directory of Open Access Journals (Sweden)

    Rinawati Rinawati

    2017-11-01

    Full Text Available In this study, the distribution and source identification of sedimentary PAHs from 13 rivers running through Jakarta City were investigated. Freeze-dried sediment samples were extracted by pressurized fluid extraction and purified by two-step of column chromatography. PAHs were identified and quantified by gas chromatography-mass spectrometry (GC-MS. High concentrations of PAHs, ranging from 1992 to 17635 ng/g-dw, were observed at all sampling locations. Ratios of alkylated PAHs to parent PAHs exhibited both petrogenic and pyrogenic signatures with predominantly petrogenic inputs. High hopanne concentrations (4238-40375 ng/g dry sediment supported the petrogenic input to Jakarta’s rivers. The high concentration of PAHs is indicator for organic micropollutant in the aquatic urban environment in Jakarta that may have the potential to cause adverse effect to the environment.

  14. Bacteria from wheat and cucurbit plant roots metabolize PAHs and aromatic root exudates: Implications for rhizodegradation.

    Science.gov (United States)

    Ely, Cairn S; Smets, Barth F

    2017-10-03

    The chemical interaction between plants and bacteria in the root zone can lead to soil decontamination. Bacteria that degrade polycyclic aromatic hydrocarbons (PAHs) have been isolated from the rhizospheres of plant species with varied biological traits; however, it is not known what phytochemicals promote contaminant degradation. One monocot and two dicotyledon plants were grown in PAH-contaminated soil from a manufactured gas plant (MGP) site. A phytotoxicity assay confirmed greater soil decontamination in rhizospheres when compared to bulk soil controls. Bacteria were isolated from plant roots (rhizobacteria) and selected for growth on anthracene and chrysene on PAH-amended plates. Rhizosphere isolates metabolized 3- and 4-ring PAHs and PAH catabolic intermediates in liquid incubations. Aromatic root exudate compounds, namely flavonoids and simple phenols, were also substrates for isolated rhizobacteria. In particular, the phenolic compounds-morin, caffeic acid, and protocatechuic acid-appear to be linked to bacterial degradation of 3- and 4-ring PAHs in the rhizosphere.

  15. Polycyclic aromatic hydrocarbon (PAH) contamination in the sediments of east coast peninsular Malaysia

    International Nuclear Information System (INIS)

    Mohd Suhaimi Elias; Abdul Khalik Wood; Zaleha Hashim; Wee Boon Siong; Mohd Suhaimi Hamzah; Shamsiah Abdul Rahman; Nazaratul Ashifa Abdullah Salim; Ariffin Talib

    2007-01-01

    The polycyclic hydrocarbons (PAHs) are pollutants of concern due to their persistent in the marine ecosystem, thus its can cause long-term adverse effect to the marine life. In this study the concentrations of PAHs in east coast Peninsular Malaysia sediments were determined. About ten stations along the east coast of the coastal area were selected to collect sediments sample using grab sampler. The PAHs from the sediment samples were soxhlet extracted using mixture of hexane and dichloromethane (DCM). Fractionation was done using the silica-alumina column. About 17 compounds of the PAHs were determined using the Gas Chromatography-Mass Spectrometer (GCMS model QP5050A). The Σ PAHs was found in the range between 0.26 μg/ g to 0.59 μg/ g dry weight. The data from the study signified that the main source of PAHs in the sediment of the east coast peninsular Malaysia is originated from the pyrolytic source. (author)

  16. Formation of nitro-PAHs from the heterogeneous reaction of ambient particle-bound PAHs with NO3/N2O5

    Science.gov (United States)

    Zimmermann, K.; Jariyasopit, N.; Simonich, S. L.; Atkinson, R.; Arey, J.

    2012-12-01

    Polycyclic aromatic hydrocarbons (PAHs) and their nitrated derivatives (nitro-PAHs) have been shown to be mutagenic in bacterial and mammalian assays and are classified as probable human carcinogens. Semi-volatile PAHs partition between the gas and particulate phases, depending on their liquid-phase vapor pressures and ambient temperatures. These PAHs have been extensively measured in ambient particulate matter and can ultimately undergo long-range transport from source regions (e.g., China to the western USA) (1). During transport these particle-bound PAHs may undergo reaction with NO3/N2O5 to form nitro-PAH derivatives. Previous studies of heterogeneous nitration of PAHs have used particles composed of graphite, diesel soot, and wood smoke (2-4). This study investigates the heterogeneous formation of nitro-PAHs from ambient particle-bound PAHs from Beijing, China and sites located within the Los Angeles air basin. These ambient particle samples, along with filters coated with isotopically labeled PAHs, were exposed to a mix of NO2/NO3/N2O5 in a 7000 L Teflon chamber, with analysis focused on the heterogeneous formation of molecular weight 247 and 273 nitro-PAHs. The heterogeneous formation of certain nitro-PAHs (including1-nitropyrene and 1- and 2-nitrotriphenylene) was observed for some, but not all, ambient samples. Formation of nitro-PAHs typically formed through gas-phase reactions (2-nitrofluoranthene and 2-nitropyrene) was not observed. The effect of particle age and local photochemical conditions during sampling on the degree of nitration in environmental chamber reactions, as well as ambient implications, will be presented. 1. Primbs, T.; Simonich, S.; Schmedding, D.; Wilson, G.; Jaffe, D.; Takami, A.; Kato, S.; Hatakeyama, S.; Kajii, Y. Environ. Sci. Technol. 2007, 41, 3551-3558. 2. Esteve, W.; Budzinski, H.; Villenave, E. Atmospheric Environment 2004, 38, 6063-6072. 3. Nguyen, M.; Bedjanian, Y.; Guilloteau, A. Journal of Atmospheric Chemistry 2009, 62

  17. Estimating the contributions of mobile sources of PAH to urban air using real-time PAH monitoring.

    Science.gov (United States)

    Dunbar, J C; Lin, C I; Vergucht, I; Wong, J; Duran, J L

    2001-11-12

    Motor vehicles are a significant source of airborne polycyclic aromatic hydrocarbons (PAH) in many urban areas. Traditional approaches used in determining the relative contributions of individual vehicle types to the total amount of PAH in air have been based on the analysis of integrated samples of airborne particles and gases for the presence of chemical tracers indicative of the vehicles from which the chemicals derived. As an alternative, we have used a photoelectric aerosol sensor (PAS) capable of measuring PAH levels in real-time in the emissions plumes from motor vehicles. We placed the PAS near a traffic-light in Kenmore Square, a busy crossroads in downtown Boston (MA, USA). A video camera co-located at the site recorded the vehicles passing the sensor, and this record was correlated with the PAS data. During a 5-day monitoring period (approximately 59 h) in the summer of 1998, over 34,000 motor vehicles were counted and classified and over 24,000 PAS readings were recorded (frequency = 1/8.6 s). The composition of the vehicle population was 94% passenger vehicles, 1.4% buses, 2.6% small trucks, 1.3% medium trucks, 0.35% large trucks, and 0.45% garbage and construction trucks. In analyzing the PAS data, it was assumed that the highest PAS measurements--those that exceeded the 95% critical level of the 5-min moving average of all the PAS measurements--were indicative of primary vehicular emissions. We found that approximately 46% of the mass of particle-bound PAH (i.e. approximately 46% of the integrated area under the PAS signal vs. time plots) was attributable to primary emissions from motor vehicles passing the sensor. Of this, 35-61% was attributable to passenger vehicles (cars, pickup trucks, and sports utility vehicles) and 39-65% was attributable to non-passenger vehicles [buses (14-23%), small trucks (12-20%), medium trucks (8.4-14%), large trucks (2.9-4.8%) and garbage and construction trucks (1.9-3.2%)]. Our results suggest that on a per vehicle

  18. Biomonitoring of PAHs by using Quercus ilex leaves: Source diagnostic and toxicity assessment

    Science.gov (United States)

    De Nicola, Flavia; Claudia, Lancellotti; MariaVittoria, Prati; Giulia, Maisto; Anna, Alfani

    2011-03-01

    Quercus ilex L. leaves were sampled at nineteen urban sites and two remote sites in order to evaluate PAH contamination degree. One-, two- and three-year-old leaves were collected and leaf lipid content was measured to investigate the influence of leaf age and lipids in PAH accumulation. Some PAH diagnostic ratios, such as Ant/Ant + Phen, Flt/Flt + Pyr, B[a]A/B[a]A + Crys and IP/IP + B[g,h,i]P, were calculated. The results suggest that Q. ilex leaves are effective biomonitors of PAH air contamination: in fact, a great PAH accumulation in leaves from the urban areas, until 30-time higher compared to those from the remote sites, has been observed. At each site, the similar total PAH concentrations in leaves of different age, probably due to a canopy effect, indicate an ability of all leaf age classes to monitor local PAH concentrations in air, remarking practical implications for air biomonitoring. The findings suggest that PAH adsorption in Q. ilex leaves does not result limited by leaf lipid content. Moreover, this study demonstrates the source-diagnostic potential of Q. ilex leaves, because, in particular, the Flt/Flt + Pyr and IP/IP + B[g,h,i]P ratios indicate vehicular traffic as the main source of PAHs in the urban areas and wood combustion in the remote areas. Moreover, to distinguish biomass combustion source, a promising tracer PAH as DB[a,h]A could be used. The high contribution of DB[a,h]A to total PAH concentrations at the remote sites determines a high carcinogenic potential in this area, similar to that calculated for the urban area where the carcinogenic PAH concentrations in absolute values are often higher.

  19. Response of microbial activities and diversity to PAHs contamination at coal tar contaminated land

    Science.gov (United States)

    Zhao, Xiaohui; Sun, Yujiao; Ding, Aizhong; Zhang, Dan; Zhang, Dayi

    2015-04-01

    Coal tar is one of the most hazardous and concerned organic pollutants and the main hazards are polycyclic aromatic hydrocarbons (PAHs). The indigenous microorganisms in soils are capable to degrade PAHs, with essential roles in biochemical process for PAHs natural attenuation. This study investigated 48 soil samples (from 8 depths of 6 boreholes) in Beijing coking and chemistry plant (China) and revealed the correlation between PAHs contamination, soil enzyme activities and microbial community structure, by 16S rRNA denaturing gradient gel electrophoresis (DGGE). At the site, the key contaminants were identified as naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene and anthracene, and the total PAHs concentration ranged from 0.1 to 923.9 mg/kg dry soil. The total PAHs contamination level was positively correlated (pcatalase activities (0.554-6.230 mL 0.02 M KMnO4/g•h) and dehydrogenase activities (1.9-30.4 TF μg/g•h soil), showing the significant response of microbial population and degrading functions to the organic contamination in soils. The PAHs contamination stimulated the PAHs degrading microbes and promoted their biochemical roles in situ. The positive relationship between bacteria count and dehydrogenase activities (p<0.05) suggested the dominancy of PAHs degrading bacteria in the microbial community. More interestingly, the microbial community deterioration was uncovered via the decline of microbial biodiversity (richness from 16S rRNA DGGE) against total PAHs concentration (p<0.05). Our research described the spatial profiles of PAHs contamination and soil microbial functions at the PAHs heavily contaminated sites, offering deeper understanding on the roles of indigenous microbial community in natural attenuation process.

  20. Influence of the sunflower rhizosphere on the biodegradation of PAHs in soil

    OpenAIRE

    Tejeda Agredano, M. C.; Gallego, Sara; Vila, Joaquim; Ortega Calvo, J. J.; Cantos, Manuel

    2013-01-01

    Reduced bioavailability to soil microorganisms is probably the most limiting factor in the bioremediation of polycyclic aromatic hydrocarbons PAH-polluted soils. We used sunflowers planted in pots containing soil to determine the influence of the rhizosphere on the ability of soil microbiota to reduce PAH levels. The concentration of total PAHs decreased by 93% in 90 days when the contaminated soil was cultivated with sunflowers, representing an improvement of 16% compared to contaminated soi...

  1. A Mid-Infrared Search for Kardashev Civilizations

    Science.gov (United States)

    Sigurdsson, Steinn; Wright, J.; Griffith, R.; Povich, M. S.

    2014-01-01

    We are using the WISE all-sky Source Catalog to search for and put upper limits on the existence of extraterrestrial civilizations with large energy supplies. Any galaxy-spanning (Type III) civilization with an energy supply of more than about one percent of its stellar luminosity will have detectable mid-infrared excess, and nearby (extended) galaxies with civilizations with supplies more than about 80% of their stellar luminosity will be well-distinguished from nearly all natural sources in WISE color-color space. Mid-infrared spectra, far-infrared photometry, and radio emission from CO can all be used to distinguish extraterrestrial mid-infrared radiation from dust.

  2. Planck early results. XVII. Origin of the submillimetre excess dust emission in the Magellanic Clouds

    DEFF Research Database (Denmark)

    Lähteenmäki, A.; Poutanen, T.; Natoli, P.

    2011-01-01

    The integrated spectral energy distributions (SED) of the Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC) appear significantly flatter than expected from dust models based on their far-infrared and radio emission. The still unexplained origin of this millimetre excess is investigate...

  3. 34 CFR 668.166 - Excess cash.

    Science.gov (United States)

    2010-07-01

    ... the Secretary for the costs the Secretary incurred in providing that excess cash to the institution... 34 Education 3 2010-07-01 2010-07-01 false Excess cash. 668.166 Section 668.166 Education..., DEPARTMENT OF EDUCATION STUDENT ASSISTANCE GENERAL PROVISIONS Cash Management § 668.166 Excess cash. (a...

  4. 10 CFR 904.10 - Excess energy.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Excess energy. 904.10 Section 904.10 Energy DEPARTMENT OF ENERGY GENERAL REGULATIONS FOR THE CHARGES FOR THE SALE OF POWER FROM THE BOULDER CANYON PROJECT Power Marketing § 904.10 Excess energy. (a) If excess Energy is determined by the United States to be available...

  5. 7 CFR 985.56 - Excess oil.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Excess oil. 985.56 Section 985.56 Agriculture... HANDLING OF SPEARMINT OIL PRODUCED IN THE FAR WEST Order Regulating Handling Volume Limitations § 985.56 Excess oil. Oil of any class in excess of a producer's applicable annual allotment shall be identified as...

  6. Relationship between polycyclic aromatic hydrocarbons (PAHs) and particle size in dated core sediments in Lake Lianhuan, Northeast China

    International Nuclear Information System (INIS)

    Sun, Li; Zang, Shuying

    2013-01-01

    Atmospheric particle associated with pyrogenic polycyclic aromatic hydrocarbons (PAHs) poses serious threats to human health by inhalation exposure, especially in semiarid areas. Hence, the distributions of PAHs and particle size in two core sediments collected from Lake Lianhuan, Northeast China were studied. The sediments were dated radiometrically, and particle size distribution and PAH concentration were evaluated and potential human health risk was assessed. From 1980 to 2007, the dominant PAHs in the two cores were 2- and 3-ring PAHs, and the concentrations of 3–6 ring PAHs gradually increased from the early 1990s. Diagnostic ratios indicated that pyrogenic PAHs were the main sources of PAHs which changed over time from combustions of wood and coal to liquid fossil fuel sources. Fine particles ( 125 μm were found. Future research should focus on the seven carcinogenic pyrogenic PAHs due to a rapidly increasing trend since 1995 based on the assessment of toxic equivalency factors. - Highlights: • PAHs and particle size in core sediments were used to evaluate the role of eolian particles in delivering pyrogenic PAHs. • Changes of PAH sources closely followed local historical socioeconomic development since 1980s. • Changes of particulate sources from eolian to lacustrine reflected the evolving history of the lake. • Significant correlations between pyrogenic PAHs and eolian particles indicated potential risk from inhalation exposure. • Petroleum source PAHs are likely to stick to coarse particles and accumulate in lake sediments by surface runoff

  7. THE INFRARED SPECTROSCOPY OF POLYCYCLIC AROMATIC HYDROCARBONS WITH FIVE- AND SEVEN-MEMBERED FUSED RING DEFECTS

    International Nuclear Information System (INIS)

    Ricca, Alessandra; Bauschlicher, Charles W. Jr; Allamandola, Louis J.

    2011-01-01

    Polycyclic aromatic hydrocarbon (PAH) growth and destruction are thought to proceed via the occasional incorporation of five- and seven-membered fused ring defects in the hexagonal carbon skeleton. Using density functional theory, this paper investigates the effect such five- and seven-membered fused ring defects have on the infrared spectra of ovalene, circumovalene, and circumcircumovalene. The defects make only small changes to the overall infrared (IR) spectra, both in the mid-IR and in the far-IR, of these species. In addition to small shifts in the positions of the bands between the PAHs with and without defects, the most common effect of the defects is to increase the number of bands. Except for an anion with the Stone-Wales defect, all of the species studied have the C-C stretching band at 6.3 μm or at longer wavelengths, the position in Classes B and C astronomical PAH spectra. In the case of the Stone-Wales anion, the band falls at 6.20 μm, suggesting that further study of defects is probably worthwhile, as some PAHs with defects might be important in those sources (Class A) that show a C-C stretching band that falls near 6.2 μm.

  8. Mid-Infrared Silicate Dust Features in Seyfert 1 Spectra

    Science.gov (United States)

    Thompson, Grant D.; Levenson, N. A.; Sirocky, M. M.; Uddin, S.

    2007-12-01

    Silicate dust emission dominates the mid-infrared spectra of galaxies, and the dust produces two spectral features, at 10 and 18 μm. These features' strengths (in emission or absorption) and peak wavelengths reveal the geometry of the dust distribution, and they are sensitive to the dust composition. We examine mid-infrared spectra of 32 Seyfert 1 active galactic nuclei (AGN), observed with the Infrared Spectrograph aboard the Spitzer Space Telescope. In the spectra, we typically find the shorter-wavelength feature in emission, at an average peak wavelength of 10.0 μm, although it is known historically as the "9.7 μm" feature. In addition, peak wavelength increases with feature strength. The 10 and 18 μm feature strengths together are sensitive to the dust geometry surrounding the central heating engine. Numerical calculations of radiative transfer distinguish between clumpy and smooth distributions, and we find that the surroundings of these AGN (the obscuring "tori" of unified AGN schemes) are clumpy. Polycyclic aromatic hydrocarbon (PAH) features are associated with star formation, and we find strong PAH emission (luminosity ≥ 1042 erg/s) in only four sources, three of which show independent evidence for starbursts. We will explore the effects of luminosity on dust geometry and chemistry in a comparison sample of quasars. We acknowledge work supported by the NSF under grant number 0237291.

  9. Dissipation of polycyclic aromatic hydrocarbons (PAHs) in the rhizosphere: Synthesis through meta-analysis

    International Nuclear Information System (INIS)

    Ma Bin; He Yan; Chen Huaihai; Xu Jianming; Rengel, Zed

    2010-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are widespread and persistent organic pollutants with high carcinogenic effect and toxicity; their behavior and fate in the soil-plant system have been widely investigated. In the present paper, meta-analysis was used to explore the interaction between plant growth and dissipation of PAHs in soil based on the large body of published literature. Plants have a promoting effect on PAH dissipation in soils. There was no difference in PAH dissipation between soils contaminated with single and mixed PAHs. However, plants had a more obvious effect on PAH dissipation in freshly-spiked soils than in long-term field-polluted soils. Additionally, a positive effect of the number of microbial populations capable of degrading PAHs was observed in the rhizosphere compared with the bulk soil. Our meta-analysis established the importance of the rhizosphere effect on PAH dissipation in variety of the soil-plant systems. - The meta-analysis provides the first quantitative evidence of the positive effect of rhizosphere processes on PAH dissipation.

  10. PAHs pollution from traffic sources in air of Hangzhou, China: trend and influencing factors.

    Science.gov (United States)

    Zhu, Li-Zhong; Wang, Jing

    2005-01-01

    PAHs pollution in air of arterial roads was investigated from October 1998 to October 2001 in Hangzhou, China. The results showed that sigma10 PAHs was 13-36 microg/m3, among which, BaP, a strong carcinogenic kind ranged from 0.034 microg/m3 to 0.12 microg/m3. PAHs pollutions in four seasons were winter > autumn > spring-summer. The annual averages of sigmaPAHs concentration were 25 microg/m3 for 1999, 28 microg/m3 for 2000, and 29 microg/m3 for 2001, respectively. Leaded gasoline was banned in December 1998 in Hangzhou, thus comparative measurements with PAHs in leaded and lead-free gasoline powered motor exhausts made it certain that the use of lead-free gasoline leaded to a heavier PAHs pollution in roadside air from December, 1998, in China, and sigmaPAHs in air samples after the lead-banning were more than twice of that in samples before the action. For the large contribution of vehicle discharge to air pollution in roadside, further research was performed to suggest the factors influencing PAHs distribution in vehicle exhaust in order to control air pollution effectively. Compared to gasoline engines, emissions from diesel engines were less toxic, although they might produce more PAHs. Of the same vehicular and oil type, automobiles of longer mileages produced more toxic PAHs. PAHs distributions in the vehicular exhausts were related to the oil type. Large difference was found in the abundance of 3-, 5- and 6-ring PAHs between exhausts from gasoline and diesel oil engines. Diesel oil engines produced relative lighter PAHs such as NAPH, ACEN, FLUOR, while gasoline engines emitted heavier kinds such as BkF, IN and BP. The automobile produced more PAHs with the increase of mileage especially FLUR, PY, BaP, BP. Some significant ratios for traffic source in Hangzhou such as PHEN/AN, FLUR/PY, IN/BP were 0.50-4.3, 0.58-7.4, 0.51-1.5, respectively. A source fingerprint for vehicle exhausts of a mixture of vehicle and oil types in the city district for light

  11. Effects of profession on urinary PAH metabolite levels in the US population.

    Science.gov (United States)

    Liu, Bian; Jia, Chunrong

    2016-01-01

    Although exposure to polycyclic aromatic hydrocarbons (PAHs) is common in both environmental and occupational settings, few studies have compared PAH exposure among people with different professions. The purpose of this study was to investigate the variations in recent PAH exposure among different occupational groups over time using national representative samples. The study population consisted of 4162 participants from the 2001 to 2008 National Health and Nutrition Examination Survey, who had both urinary PAH metabolites and occupational information. Four corresponding monohydroxy-PAH urine metabolites: naphthalene (NAP), fluorene (FLUO), phenanthrene (PHEN), and pyrene (PYR) among seven broad occupational groups were analyzed using weighted linear regression models, adjusting for creatinine levels, sociodemographic factors, smoking status, and sampling season. The overall geometric mean concentrations of NAP, FLUO, PHEN, and PYR were 6927, 477, 335, and 87 ng/L, respectively. All four PAH metabolites were elevated in the "extractive, construction, and repair (ECR)" group, with 21-42 % higher concentrations than those in the reference group of "management." Similar trends were seen in the "operators, fabricators, and laborers (OFL)" group for FLUO, PHEN, and PYR. In addition, both "service" and "support" groups had elevated FLUO. Significant (p PAH exposure. Heterogeneous distributions of urinary PAH metabolites among people with different job categories exist at the population level. The upward temporal trends in NAP and PYR warrant reduction in PAH exposure, especially among those with OFL and ECR occupations.

  12. Impact of soil organic matter on the distribution of polycyclic aromatic hydrocarbons (PAHs) in soils

    International Nuclear Information System (INIS)

    Yang, Y.; Zhang, N.; Xue, M.; Tao, S.

    2010-01-01

    The knowledge on the distribution of hydrophobic organic contaminants in soils can provide better understanding for their fate in the environment. In the present study, the n-butanol extraction and humic fractionation were applied to investigate the impact of SOM on the distribution of polycyclic aromatic hydrocarbons (PAHs). The results indicated that 80.5%-94.8% of the target PAHs could be extracted by n-butanol and 63.1%-94.6% of PAHs were associated with fulvic acid (FA). Concentrations of un-extracted PAHs increased significantly with the increasing soil organic matter (SOM), however, such an association was absent for the extractable fractions. The results suggested that the sequestration played a critical role in the accumulation of PAHs in soils. SOM also retarded the diffusion of PAHs into the humin fractions. It implied that sequestration in SOM was critical for PAH distribution in soils, while the properties of PAH compounds also had great influences. - Soil organic matter played an important role in the distribution of PAHs in soils through sequestration.

  13. Molecular and stable carbon isotopic characterization of PAH contaminants at McMurdo Station, Antarctica

    International Nuclear Information System (INIS)

    Kim, Moonkoo . E-mail moonkoo.kim@wmich.edu; Kennicutt, Mahlon C.; Qian Yaorong

    2006-01-01

    The molecular and stable carbon isotopic compositions of contaminant polycyclic aromatic hydrocarbons (PAHs) at McMurdo Station, Antarctica were analyzed in samples collected from land and sub-tidal area. PAHs in the study areas were characterized by high amounts of naphthalene and alkylated naphthalenes from petroleum products introduced by human activities in the area. Principal component analysis (PCA) of PAH composition data identified multiple sources of PAH contamination in the study area. Compositional assignments of origins were confirmed using compound specific stable carbon isotopic analysis

  14. Assessment of polycyclic aromatic hydrocarbons (PAHs) in mussels (Mytilus galloprovincialis) of Prince Islands, Marmara Sea.

    Science.gov (United States)

    Balcıoğlu, Esra Billur

    2016-08-15

    In this study, PAH analyses have been conducted on indigenous mussels. Mussel samples (Mytilus galloprovincialis) have been collected from seven stations of Prince Islands during September 2015. Concentrations of total determined PAHs (sum of 16 compounds) ranged between 664 and 9083ngg(-1). The origin of PAHs has been found to be pyrolytic according to the PHE/ANT and FA/PYR ratios in Büyükada. For other islands, PAH origins have been observed as pyrolytic and petrogenic together according to the PHE/ANT, FA/PYR and BaA/CHR ratios. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Pollution by polycyclic aromatic hydrocarbons (PAH's) in sediments and organisms from Salina Cruz Port, Oaxaca, Mexico

    International Nuclear Information System (INIS)

    Botello, A.V.; Villanueva, S.; Diaz, G.; Pica, Y.

    1995-01-01

    The presence and levels of polycyclic aromatic hydrocarbons (PAH's) in [sediments and biota from the Port of Salina Cruz, Oaxaca; were evaluated by means of gas capillary chromatography using columns of high resolution. The results show a seasonal variability of the PAH's concentrations in sediments being higher in the port area and lower in oceanic sediments. The increase of the PAH's levels in Crassostrea iridiscens and Penaeus stylirostris is important and related to the bioaccumulation process. The presence of PAH's conformed by 4 y 5 benzene rings in these species must be noted specially because they have carcinogenic properties and their effects on the local fisheries should be considered. (Author)

  16. Cell size dependence of additive versus synergetic effects of UV radiation and PAHs on oceanic phytoplankton

    International Nuclear Information System (INIS)

    Echeveste, Pedro; Agusti, Susana; Dachs, Jordi

    2011-01-01

    Polycyclic Aromatic Hydrocarbons' (PAHs) toxicity is enhanced by the presence of ultraviolet radiation (UVR), which levels have arisen due to the thinning of the ozone layer. In this study, PAHs' phototoxicity for natural marine phytoplankton was tested. Different concentrations of a mixture of 16 PAHs were added to natural phytoplankton communities from the Mediterranean Sea, Atlantic, Arctic and Southern Oceans and exposed to natural sunlight received in situ, including treatments where the UVR bands were removed. PAHs' toxicity was observed for all the phytoplankton groups studied in all the waters and treatments tested, but only for the pico-sized group a synergetic effect of the mixture and UVR was observed (p = 0.009). When comparing phototoxicity in phytoplankton from oligotrophic and eutrophic waters, synergy was only observed at the oligotrophic communities (p = 0.02) where pico-sized phytoplankton dominated. The degree of sensitivity was related to the trophic degree, decreasing as Chlorophyll a concentration increased. - Highlights: → The smallest picocyanobacteria were the most sensitive to PAHs and UVR. → PAHs-UVR synergism for the picophytoplankton and the oligotrophic communities. → PAHs-UVR additivity for the nanophytoplankton and the eutrophic communities. → An irradiance threshold is suggested to determine the joint action of UVR and PAHs. - Cell size and UVR levels determine additive/synergetic effects of PAHs and UVR to oceanic phytoplankton.

  17. Comparative survey of PAHs incidence in Portuguese traditional meat and blood sausages.

    Science.gov (United States)

    Roseiro, L C; Gomes, A; Patarata, L; Santos, C

    2012-06-01

    Sixteen polycyclic aromatic hydrocarbons (PAHs) in representative traditional sausages produced in "Trás-os-Montes" and "Alentejo", were determined. Light PAHs represented similar overall contents in both regions and showed close decreasing order patterns (ACY, PHE, FLR and NAP), irrespective of the product type considered. Amongst the carcinogenic/mutagenic PAHs analyzed (PAH8), both regions also had greater contents associated to BaA and CHR, with slightly higher values for the former compound in "Alentejo" and, oppositely, for the later in "Trás-os-Montes". However, their quantitative comparison showed that the general mean total PAH content found in "Trás-os-Montes" was almost 3-fold higher than in similar products from "Alentejo" and this factor was about 8-fold superior when the PAH8 and PAH4 indicators were compared, expressing benzo[a]pyrene toxic equivalencies (BaPE), 15 times (total mean toxicity), 34 times (PAH8) and 9 times (PAH4) higher. In general terms, the mean BaP content of all analyzed samples from "Alentejo" was 0.41 μg kg(-1). Differently that value in "Trás-os-Montes" reached 3.57 μg kg(-1), expressing concerning average contents of 5.35, 5.87 and 4.51 μg kg(-1) in Chouriço de Carne, Moura and Salpicão sausages, respectively. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Evolution of bacterial community during bioremediation of PAHs in a coal tar contaminated soil

    Energy Technology Data Exchange (ETDEWEB)

    Lors, C.; Ryngaert, A.; Perie, F.; Diels, L.; Damidot, D. [University of Lille, Lille (France)

    2010-11-15

    The monitoring of a windrow treatment applied to soil contaminated by mostly 2, 3- and 4-ring PAHs produced by coal tar distillation was performed by following the evolution of both PAH concentration and the bacterial community. Total and PAH-degrading bacterial community structures were followed by 165 rRNA PCR-DGGE in parallel with quantification by bacterial counts and 16 PAH measurements. Six months of biological treatment led to a strong decrease in 2-, 3- and 4-ring PAH concentrations (98, 97 and 82%, respectively). This result was associated with the activity of bacterial PAH-degraders belonging mainly to the Gamma proteobacteria, in particular the Enterobacteria and Pseudomonas genera which were detected over the course of the treatment. This group was considered to be a good bioindicator to determine the potential PAH biodegradation of contaminated soil. Conversely other species like the Beta proteobacteria were detected after 3 months when 2-, 3- and 4-ring PAHs were almost completely degraded. Thus presence of the Beta proteobacteria group could be considered a good candidate indicator to estimate the endpoint of biotreatment of this type of PAH contaminated soil.

  19. Levels and patterns of polycyclic aromatic hydrocarbons (PAHs) in soils after forest fires in South Korea.

    Science.gov (United States)

    Kim, Eun Jung; Choi, Sung-Deuk; Chang, Yoon-Seok

    2011-11-01

    To investigate the influence of biomass burning on the levels of polycyclic aromatic hydrocarbons (PAHs) in soils, temporal trends and profiles of 16 US Environmental Protection Agency priority PAHs were studied in soil and ash samples collected 1, 5, and 9 months after forest fires in South Korea. The levels of PAHs in the burnt soils 1 month after the forest fires (mean, 1,200 ng/g dry weight) were comparable with those of contaminated urban soils. However, 5 and 9 months after the forest fires, these levels decreased considerably to those of general forest soils (206 and 302 ng/g, respectively). The burnt soils and ash were characterized by higher levels of light PAHs with two to four rings, reflecting direct emissions from biomass burning. Five and 9 months after the forest fires, the presence of naphthalene decreased considerably, which indicates that light PAHs were rapidly volatilized or degraded from the burnt soils. The temporal trend and pattern of PAHs clearly suggests that soils in the forest-fire region can be contaminated by PAHs directly emitted from biomass burning. However, the fire-affected soils can return to the pre-fire conditions over time through the washout and wind dissipation of the ash with high content of PAHs as well as vaporization or degradation of light PAHs.

  20. Laboratory determination of the infrared band strengths of pyrene frozen in water ice: Implications for the composition of interstellar ices

    Energy Technology Data Exchange (ETDEWEB)

    Hardegree-Ullman, E. E. [New York Center for Astrobiology and Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180 (United States); Gudipati, M. S.; Werner, M. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Boogert, A. C. A. [Infrared Processing and Analysis Center, Mail Code 100-22, California Institute of Technology, Pasadena, CA 91125 (United States); Lignell, H. [Department of Chemistry, University of California Irvine, Irvine, CA 92697-2025 (United States); Allamandola, L. J. [Space Science Division, Mail Stop 245-6, NASA Ames Research Center, Moffett Field, CA 94035 (United States); Stapelfeldt, K. R., E-mail: hardee@rpi.edu, E-mail: gudipati@jpl.nasa.gov [NASA Goddard Space Flight Center, Exoplanets and Stellar Astrophysics Laboratory, Code 667, Greenbelt, MD 20771 (United States)

    2014-04-01

    Broad infrared emission features (e.g., at 3.3, 6.2, 7.7, 8.6, and 11.3 μm) from the gas phase interstellar medium have long been attributed to polycyclic aromatic hydrocarbons (PAHs). A significant portion (10%-20%) of the Milky Way's carbon reservoir is locked in PAH molecules, which makes their characterization integral to our understanding of astrochemistry. In molecular clouds and the dense envelopes and disks of young stellar objects (YSOs), PAHs are expected to be frozen in the icy mantles of dust grains where they should reveal themselves through infrared absorption. To facilitate the search for frozen interstellar PAHs, laboratory experiments were conducted to determine the positions and strengths of the bands of pyrene mixed with H{sub 2}O and D{sub 2}O ices. The D{sub 2}O mixtures are used to measure pyrene bands that are masked by the strong bands of H{sub 2}O, leading to the first laboratory determination of the band strength for the CH stretching mode of pyrene in water ice near 3.25 μm. Our infrared band strengths were normalized to experimentally determined ultraviolet band strengths, and we find that they are generally ∼50% larger than those reported by Bouwman et al. based on theoretical strengths. These improved band strengths were used to reexamine YSO spectra published by Boogert et al. to estimate the contribution of frozen PAHs to absorption in the 5-8 μm spectral region, taking into account the strength of the 3.25 μm CH stretching mode. It is found that frozen neutral PAHs contain 5%-9% of the cosmic carbon budget and account for 2%-9% of the unidentified absorption in the 5-8 μm region.

  1. Multi-wavelength study of infrared galaxies

    International Nuclear Information System (INIS)

    Marcillac, Delphine

    2005-01-01

    This thesis deals with a panchromatic study of luminous infrared galaxies (LIRGs) detected at 15 microns by ISOCAM (camera aboard ISO) and at 24 microns by MIPS (camera aboard the recently launched Spitzer satellite). These galaxies are today considered to be the Rosetta Stone of galaxy evolution since they are found to be far more numerous at high redshift and it is thought that a large part of stars seen in the local universe are born in such phases. The first part of this thesis presents a new study dedicated to dust emission of distant LIRGs in the mid-infrared range. Their dust emission has been compared to those of a local sample of LIRGs in addition to the prediction of several spectral energy distributions (SEDs) built on data available in the local universe. It has been shown that distant and local LIRGs present similar mid infrared spectral energy distribution: similar PAH bumps are detected in both local and distant LIRGs, however distant LIRGs show evidence of a stronger silicate absorption at 10 microns associated silicate grains. It also shows that distant LIRG mid infrared emission can be used together with local SEDs in order to estimate the total infrared luminosity. The second part of this thesis is dedicated to the burst of star formation and to the recent star formation history of these galaxies, which is responsible for the dust emission. This study was done thanks to a combination of high resolution spectra (R=2000 in the rest frame) obtained at VLT/FORS2 and the stellar population synthesis models called GALAXEV (Bruzual and Charlot, 2003). It has been shown that the burst of star formation has a duration of about 0.1 Gyear. About 10 % of the stellar content is formed during this burst of star formation. (author) [fr

  2. Heavy metal effects on the biodegradation of fluorene by Sphingobacterium sp. KM-02 isolated from PAHs-contaminated mine soil

    Science.gov (United States)

    Nam, I.; Chon, C.; Jung, K.; Kim, J.

    2012-12-01

    Polycyclic aromatic hydrocarbon compounds (PAHs) are widely distributed in the environment and occur ubiquitously in fossil fuels as well as in products of incomplete combustion and are known to be strongly toxic, often with carcinogenic and mutagenic properties. Fluorene is one of the 16 PAHs included in the list of priority pollutants of the Environmental Protection Agency. The fluorene-degrading bacterial strain Sphingobacterium sp. KM-02 was isolated from PAHs-contaminated soil near an abandoned mine impacted area by selective enrichment techniques. Fluorene added to the Sphingobacterium sp. KM-02 culture as sole carbon and energy source was 78.4% removed within 120 h. A fluorene degradation pathway is tentatively proposed based on mass spectrometric identification of the metabolic intermediates 9-fluorenone, 4-hydroxy-9-fluorenone, and 8-hydroxy-3,4-benzocoumarin. Further the ability of Sphingobacterium sp. KM-02 to bioremediate 100 mg/kg fluorene in mine soil was examined by composting under laboratory conditions. Treatment of microcosm soil with the strain KM-02 for 20 days resulted in a 65.6% reduction in total amounts. These results demonstrate that Sphingobacterium sp. KM-02 could potentially be used in the bioremediation of fluorene from contaminated soil. Mine impacted area comprises considerable amounts of heavy metals such as cadmium, lead, mercury, arsenic, and copper. Although some of these metals are necessary for biological life, excessive quantities often result in the inhibition of essential biological reactions via numerous pathways. A number of reports collectively show that various metals, such as Al, Co, Ni, Cu, Zn, Pb, and Hg at a range of concentrations have adverse effects on the degradation of organic compounds. However, at present there is only limited information on the effect of individual heavy metals on the biological degradation of polyaromatic hydrocarbons (PAHs) including fluorene. Moreover, heavy metal effects were not

  3. Comparing PAH availability from manufactured gas plant soils and sediments with chemical and biological tests. 1. PAH release during water desorption and supercritical carbon dioxide extraction

    Energy Technology Data Exchange (ETDEWEB)

    Hawthorne, S.B.; Poppendieck, D.G.; Grabanski, C.B.; Loehr, R.C. [University of North Dakota, Grand Forks, ND (US). Energy and Environmental Research Center

    2002-11-15

    Soil and sediment samples from OG (oil gas) and CG (coal gas) manufactured gas plant (MGP) sites in the United States that had been closed for about 50 years were selected to represent a range of PAH concentrations and sample matrix compositions. Samples varied from vegetated soils to lampblack soot and had carbon contents from 3 to 87 wt%. Supercritical carbon dioxide, SFE desorption and water/XAD{sub 2} desorption curves were determined and fit with a simple two-site model to determine the rapid-released fraction (F) for PAHs ranging from naphthalene to benzo-(ghi)perylene. F values varied greatly among the samples. Release rates did not correlate with sample matrix characteristics including PAH concentrations, elemental composition or 'hard' and 'soft' organic carbon, indicating that PAH release cannot easily be estimated on the basis of sample matrix composition. F values for CG site samples obtained with SFE and water desorption agreed well but SFE yielded higher F values for the OG samples. These behaviors were attributed to the stronger ability of carbon dioxide than water to desorb PAHs from the highly aromatic (hard) carbon of the OG matrixes, while carbon dioxide and water showed similar abilities to desorb PAHs from the more polar (soft) carbon of the CG samples. The combined SFE and water desorption approaches should improve the understanding of PAH sequestration and release from contaminated soils and sediments and provide the basis for subsequent studies, using the same samples to compare PAH release with PAH availability to earthworms. 46 refs., 4 figs., 4 tabs.

  4. PAH (Polycyclic Aromatic Hydrocarbon) bioaccumulation and PAHs/shell weight index in Ruditapes philippinarum (Adams & Reeve, 1850) from the Vallona lagoon (northern Adriatic Sea, NE Italy).

    Science.gov (United States)

    Cacciatore, Federica; Bernarello, Valentina; Boscolo Brusà, Rossella; Sesta, Giulio; Franceschini, Gianluca; Maggi, Chiara; Gabellini, Massimo; Lamberti, Clauda Virno

    2018-02-01

    The Vallona lagoon is a transitional area located in the Po River delta (NE, ITALY) traditionally exploited for Manila clam (Ruditapes philippinarum) farming. During 2007-2008, a pipeline was buried in the middle of the lagoon to connect an off-shore structure to facilities on land. PAH levels were monitored in Manila clams and sediments before, during and after the pipeline construction to assess the impact of the activities through the pattern of distribution of the PAH compounds. PAH bioaccumulation in clams displayed seasonal fluctuations with higher levels in autumnal and wintry surveys than in spring-summer. Principal component analysis applied to PAHs in clams highlighted a petrogenic input during ante operam period and a pyrolytic origin during the burying activities. On the contrary, sediment PAH concentrations resulted quite similar both among sites and periods. Biota-Sediment-Accumulation-Factor values also confirmed that sediments were not the major source of PAH pollution for clams in this study. The welfare of clams was examined through two physiological indices (condition index and survival in air) to check the effects of the activities on a commercial resource. Both physiological indices exhibited seasonal variations connected to natural endogenous and exogenous factors; however survival in air was the most sensitive index in highlighting the effects of the pipeline burying activities. Finally, to ensure that PAH bioavailability assessment was not affected by seasonal variation of soft tissues of molluscs, PAHs/shell weight index was applied. Higher levels of this index were observed before and during the burying activities, whilst, after that, values significantly lowered. Moreover, the normalization enabled us to highlight the PAH uptake from clams in some particular periods and to compare different populations in a long-term biomonitoring program with data obtained from different periods of the year. Copyright © 2017 Elsevier Inc. All rights

  5. Effect of Warfarin Treatment on Survival of Patients With Pulmonary Arterial Hypertension (PAH) in the Registry to Evaluate Early and Long-Term PAH Disease Management (REVEAL).

    Science.gov (United States)

    Preston, Ioana R; Roberts, Kari E; Miller, Dave P; Sen, Ginny P; Selej, Mona; Benton, Wade W; Hill, Nicholas S; Farber, Harrison W

    2015-12-22

    Long-term anticoagulation is recommended in idiopathic pulmonary arterial hypertension (IPAH). In contrast, limited data support anticoagulation in pulmonary arterial hypertension (PAH) associated with systemic sclerosis (SSc-PAH). We assessed the effect of warfarin anticoagulation on survival in IPAH and SSc-PAH patients enrolled in Registry to Evaluate Early and Long-term PAH Disease Management (REVEAL), a longitudinal registry of group I PAH. Patients who initiated warfarin on study (n=187) were matched 1:1 with patients never on warfarin, by enrollment site, etiology, and diagnosis status. Descriptive analyses were conducted to compare warfarin users and nonusers by etiology. Survival analyses with and without risk adjustment were performed from the time of warfarin initiation or a corresponding quarterly update in matched pairs to avoid immortal time bias. Time-varying covariate models were used as sensitivity analyses. Mean warfarin treatment was 1 year; mean international normalized ratios were 1.9 (IPAH) and 2.0 (SSc-PAH). Two-thirds of patients initiating warfarin discontinued treatment before the last study assessment. There was no survival difference with warfarin in IPAH patients (adjusted hazard ratio, 1.37; P=0.21) or in SSc-PAH patients (adjusted hazard ratio, 1.60; P=0.15) in comparison with matched controls. However, SSc-PAH patients receiving warfarin within the previous year (hazard ratio, 1.57; P=0.031) or any time postbaseline (hazard ratio, 1.49; P=0.046) had increased mortality in comparison with warfarin-naïve patients. No significant survival advantage was observed in IPAH patients who started warfarin. In SSc-PAH patients, long-term warfarin was associated with poorer survival than in patients not receiving warfarin, even after adjusting for confounders. URL: http://www.clinicaltrials.gov. Unique identifier: NCT00370214. © 2015 The Authors.

  6. THE INFRARED SPECTRUM OF PROTONATED OVALENE IN SOLID PARA-HYDROGEN AND ITS POSSIBLE CONTRIBUTION TO INTERSTELLAR UNIDENTIFIED INFRARED EMISSION

    Energy Technology Data Exchange (ETDEWEB)

    Tsuge, Masashi; Bahou, Mohammed; Lee, Yuan-Pern [Department of Applied Chemistry and Institute of Molecular Sciences, National Chiao Tung University, 1001, Ta-Hsueh Road, Hsinchu 30010, Taiwan (China); Wu, Yu-Jong [National Synchrotron Radiation Research Center, 101, Hsin-Ann Road, Hsinchu 30076, Taiwan (China); Allamandola, Louis, E-mail: tsuge@nctu.edu.tw, E-mail: yplee@mail.nctu.edu.tw [The Astrophysics and Astrochemistry Laboratory, NASA Ames Research Center, Moffett Field, CA 94035 (United States)

    2016-07-10

    The mid-infrared emission from galactic objects, including reflection nebulae, planetary nebulae, proto-planetary nebulae, molecular clouds, etc, as well as external galaxies, is dominated by the unidentified infrared (UIR) emission bands. Large protonated polycyclic aromatic hydrocarbons (H{sup +}PAHs) were proposed as possible carriers, but no spectrum of an H{sup +}PAH has been shown to exactly match the UIR bands. Here, we report the IR spectrum of protonated ovalene (7-C{sub 32}H{sub 15} {sup +}) measured in a para -hydrogen ( p -H{sub 2}) matrix at 3.2 K, generated by bombarding a mixture of ovalene and p -H{sub 2} with electrons during matrix deposition. Spectral assignments were made based on the expected chemistry and on the spectra simulated with the wavenumbers and infrared intensities predicted with the B3PW91/6-311++G(2d,2p) method. The close resemblance of the observed spectral pattern to that of the UIR bands suggests that protonated ovalene may contribute to the UIR emission, particularly from objects that emit Class A spectra, such as the IRIS reflection nebula, NGC 7023.

  7. Pristine Arctic: Background mapping of PAHs, PAH metabolites and inorganic trace elements in the North-Atlantic Arctic and sub-Arctic coastal environment

    Energy Technology Data Exchange (ETDEWEB)

    Jörundsdóttir, Hrönn Ólína, E-mail: hronn.o.jorundsdottir@matis.is [Matis Ltd., Icelandic Food and Biotech R and D, Vinlandsleid 12, 113 Reykjavik (Iceland); Jensen, Sophie [Matis Ltd., Icelandic Food and Biotech R and D, Vinlandsleid 12, 113 Reykjavik (Iceland); Hylland, Ketil; Holth, Tor Fredrik [Department of Biosciences, University of Oslo, P.O. Box 1066 Blindern, N-0316 Oslo (Norway); Gunnlaugsdóttir, Helga [Matis Ltd., Icelandic Food and Biotech R and D, Vinlandsleid 12, 113 Reykjavik (Iceland); Svavarsson, Jörundur [University of Iceland, Department of Life and Environmental Sciences, Askja - Natural Science Building, Sturlugata 7, 101 Reykjavík (Iceland); Ólafsdóttir, Ásdís [The University of Iceland´s Research Centre in Sudurnes, Gardvegi 1, 245 Sandgerdi (Iceland); El-Taliawy, Haitham [Matis Ltd., Icelandic Food and Biotech R and D, Vinlandsleid 12, 113 Reykjavik (Iceland); Rigét, Frank; Strand, Jakob [Department of Bioscience, Arctic Research Centre, Aarhus University, Frederiksborgvej 399, PO Box 358, DK-4000 Roskilde (Denmark); Nyberg, Elisabeth; Bignert, Anders [Swedish Museum of Natural History, P.O. Box 50007, 104 05 Stockholm (Sweden); Hoydal, Katrin S. [The Faroese Environment Agency, Traðagøta 38, P.O. Box 2048, FO-165 Argir, the Faroe Islands (Faroe Islands); Halldórsson, Halldór Pálmar [The University of Iceland´s Research Centre in Sudurnes, Gardvegi 1, 245 Sandgerdi (Iceland)

    2014-09-15

    As the ice cap of the Arctic diminishes due to global warming, the polar sailing route will be open larger parts of the year. These changes are likely to increase the pollution load on the pristine Arctic due to large vessel traffic from specific contaminant groups, such as polycyclic aromatic hydrocarbons (PAHs). A well-documented baseline for PAH concentrations in the biota in the remote regions of the Nordic Seas and the sub-Arctic is currently limited, but will be vital in order to assess future changes in PAH contamination in the region. Blue mussels (Mytilus edulis) were collected from remote sites in Greenland, Iceland, the Faroe Islands, Norway and Sweden as well as from urban sites in the same countries for comparison. Cod (Gadus morhua) was caught north of Iceland and along the Norwegian coast. Sixteen priority PAH congeners and the inorganic trace elements arsenic, cadmium, mercury and lead were analysed in the blue mussel samples as well as PAH metabolites in cod bile. Σ{sub 16}PAHs ranged from 28 ng/g dry weight (d.w.) (Álftafjörður, NW Iceland) to 480 ng/g d.w. (Ísafjörður, NW Iceland). Mussel samples from Mjóifjörður, East Iceland and Maarmorilik, West Greenland, contained elevated levels of Σ{sub 16}PAHs, 370 and 280 ng/g d.w., respectively. Levels of inorganic trace elements varied with highest levels of arsenic in mussels from Ísafjörður, Iceland (79 ng/g d.w.), cadmium in mussels from Mjóifjörður, Iceland (4.3 ng/g d.w.), mercury in mussels from Sørenfjorden, Norway (0.23 ng/g d.w.) and lead in mussels from Maarmorilik, Greenland (21 ng/g d.w.). 1-OH-pyrene was only found above limits of quantification (0.5 ng/mL) in samples from the Norwegian coast, ranging between 44 and 140 ng/ml bile. Generally, PAH levels were low in mussels from the remote sites investigated in the study, which indicates limited current effect on the environment. - Highlights: • Low levels of PAHs in blue mussels from remote areas of the Arctic. • Low

  8. Microbial degradation of polycyclic aromatic hydrocarbons (PAHs). Pt. 1

    International Nuclear Information System (INIS)

    Eichler, B.; Bryniok, D.; Vorbeck, C.; Lutz, M.; Ackermann, B.; Freier-Schroeder, D.; Knackmuss, H.J.

    1992-01-01

    Productive degradation of the higher molecular PAHs benz(a)anthracene (four rings), benzo(a)pyrene and benzo(k)fluoranthene (five rings) through pure bacterial cultures is demonstrated in this paper for the first time. Consequently, a degradation potential for lower and higher molecular polycyclic aromatics up to five rings exists both in the ground of the fromer coking site and in the ground of the former gas works of Stuttgart. Further samples from contaminated soils, coking waste water and sediments showed similar results. This suggests that the bacterial flora present in the soil itself can be successfully used to clean up contaminated ground. (orig.) [de

  9. UV action spectroscopy of protonated PAH derivatives. Methyl substituted quinolines

    DEFF Research Database (Denmark)

    Klærke, Benedikte; Holm, Anne; Andersen, Lars Henrik

    2011-01-01

    using the electrostatic storage ring ELISA, an electrospray ion source and 3 ns UV laser pulses. Results. It is shown that the absorption profile is both redshifted and broadened when moving the methyl group from the heterocycle containing nitrogen to the homoatomic ring. The absorption profiles......Aims. We investigate the production of molecular photofragments upon UV excitation of PAH derivatives, relevant for the interstellar medium. Methods. The action absorption spectra of protonated gas-phase methyl-substituted quinolines (CH3−C9H7NH+) have been recorded in the 215–338 nm spectral range...

  10. Phytoextraction of excess soil phosphorus

    International Nuclear Information System (INIS)

    Sharma, Nilesh C.; Starnes, Daniel L.; Sahi, Shivendra V.

    2007-01-01

    In the search for a suitable plant to be used in P phytoremediation, several species belonging to legume, vegetable and herb crops were grown in P-enriched soils, and screened for P accumulation potentials. A large variation in P concentrations of different plant species was observed. Some vegetable species such as cucumber (Cucumis sativus) and yellow squash (Cucurbita pepo var. melopepo) were identified as potential P accumulators with >1% (dry weight) P in their shoots. These plants also displayed a satisfactory biomass accumulation while growing on a high concentration of soil P. The elevated activities of phosphomonoesterase and phytase were observed when plants were grown in P-enriched soils, this possibly contributing to high P acquisition in these species. Sunflower plants also demonstrated an increased shoot P accumulation. This study shows that the phytoextraction of phosphorus can be effective using appropriate plant species. - Crop plants such as cucumber, squash and sunflower accumulate phosphorus and thus can be used in the phytoextraction of excess phosphorus from soils

  11. Phytoextraction of excess soil phosphorus

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Nilesh C. [Department of Biology, Western Kentucky University, 1906 College Heights Boulevard 11080, Bowling Green, KY 42101-1080 (United States); Starnes, Daniel L. [Department of Biology, Western Kentucky University, 1906 College Heights Boulevard 11080, Bowling Green, KY 42101-1080 (United States); Sahi, Shivendra V. [Department of Biology, Western Kentucky University, 1906 College Heights Boulevard 11080, Bowling Green, KY 42101-1080 (United States)]. E-mail: shiv.sahi@wku.edu

    2007-03-15

    In the search for a suitable plant to be used in P phytoremediation, several species belonging to legume, vegetable and herb crops were grown in P-enriched soils, and screened for P accumulation potentials. A large variation in P concentrations of different plant species was observed. Some vegetable species such as cucumber (Cucumis sativus) and yellow squash (Cucurbita pepo var. melopepo) were identified as potential P accumulators with >1% (dry weight) P in their shoots. These plants also displayed a satisfactory biomass accumulation while growing on a high concentration of soil P. The elevated activities of phosphomonoesterase and phytase were observed when plants were grown in P-enriched soils, this possibly contributing to high P acquisition in these species. Sunflower plants also demonstrated an increased shoot P accumulation. This study shows that the phytoextraction of phosphorus can be effective using appropriate plant species. - Crop plants such as cucumber, squash and sunflower accumulate phosphorus and thus can be used in the phytoextraction of excess phosphorus from soils.

  12. Leaching of PAHs from agricultural soils treated with oil shale combustion ash: an experimental study.

    Science.gov (United States)

    Jefimova, Jekaterina; Adamson, Jasper; Reinik, Janek; Irha, Natalya

    2016-10-01

    The present study focuses on the fate of polycyclic aromatic hydrocarbons (PAHs) in soils amended with oil shale ash (OSA). Leachability studies to assess the release of PAHs to the environment are essential before the application of OSA in agriculture. A quantitative estimation of the leaching of PAHs from two types of soil and two types of OSA was undertaken in this study. Two leaching approaches were chosen: (1) a traditional one step leaching scheme and (2) a leaching scheme with pretreatment, i.e.., incubation of the material in wet conditions imitating the field conditions, followed by a traditional leaching procedure keeping the total amount of water constant. The total amount of PAHs leached from soil/OSA mixtures was in the range of 15 to 48 μg/kg. The amount of total PAHs leached was higher for the incubation method, compared to the traditional leaching method, particularly for Podzolic Gleysols soil. This suggests that for the incubation method, the content of organic matter and clay minerals of the soil influence the fate of PAHs more strongly compared to the traditional leaching scheme. The amount of PAHs leached from OSA samples is higher than from soil/OSA mixtures, which suggests soils to inhibit the release of PAHs. Calculated amount of PAHs from experimental soil and OSA leaching experiments differed considerably from real values. Thus, it is not possible to estimate the amount of PAHs leached from soil/OSA mixtures based on the knowledge of the amount of PAHs leached from soil and OSA samples separately.

  13. Compositional effects on PAH and soot formation in counterflow diffusion flames of gasoline surrogate fuels

    KAUST Repository

    Park, Sungwoo

    2017-02-05

    Gasoline surrogate fuels are widely used to understand the fundamental combustion properties of complex refinery gasoline fuels. In this study, the compositional effects on polycyclic aromatic hydrocarbons (PAHs) and soot formation were investigated experimentally for gasoline surrogate mixtures comprising n-heptane, iso-octane, and toluene in counterflow diffusion flames. A comprehensive kinetic model for the gasoline surrogate mixtures was developed to accurately predict the fuel oxidation along with the formation of PAHs and soot in flames. This combined model was first tested against ignition delay times and laminar burning velocities data. The proposed model for the formation and growth of PAHs up to coronene (C24H12) was based on previous studies and was tested against existing and present new experimental data. Additionally, in the accompanied soot model, PAHs with sizes larger than (including) pyrene were used for the inception of soot particles, followed by particle coagulations and PAH condensation/chemical reactions on soot surfaces. The major pathways for the formation of PAHs were also identified for the surrogate mixtures. The model accurately captures the synergistic PAH formation characteristics observed experimentally for n-heptane/toluene and iso-octane/toluene binary mixtures. Furthermore, the present experimental and modeling results also elucidated different trends in the formation of larger PAHs and soot between binary n-heptane/iso-octane and ternary n-heptane/iso-octane/toluene mixtures. Propargyl radicals (C3H3) were shown to be important in the formation and growth of PAHs for n-heptane/iso-octane mixtures when the iso-octane concentration increased; however, reactions involving benzyl radicals (C6H5CH2) played a significant role in the formation of PAHs for n-heptane/iso-octane/toluene mixtures. These results indicated that the formation of PAHs and subsequently soot was strongly affected by the composition of gasoline surrogate mixtures.

  14. Source seasonality of polycyclic aromatic hydrocarbons (PAHs) in a subtropical city, Guangzhou, South China.

    Science.gov (United States)

    Li, J; Zhang, G; Li, X D; Qi, S H; Liu, G Q; Peng, X Z

    2006-02-15

    Mega-cities are large sources of air pollution on a regional base. Differences in energy structures, geographical settings and regional climate features lead to a large variety of air pollution sources from place to place. To understand the seasonality of air pollution sources is critical to precise emission inventories and a sound protection of human health. Based on a year-round dataset, the sources of PAHs in the air of Guangzhou were drawn by principal factor analysis (PCA) in combination with diagnostic ratios, and the seasonality of these sources were analyzed by PCA/MLR (multiple linear regressions) and discussed. The average total gaseous and particulate PAHs concentrations were 313 and 23.7 ng m(-3), respectively, with a higher concentration of vapor PAHs in summer and particulate PAHs in winter. In addition to vehicle exhaust, which contributed 69% of the particulate PAHs, coal combustion was still an important source and contributed 31% of the particulate PAHs. Relatively constant contribution from coal combustion was found through the year, implying that coal combustion in power plants was not a seasonally dependent source. Evaporation from contaminated ground may be an important source of light PAHs in summer, providing an average contribution of 68% to the total PAHs in this study. By comparing the PAH concentrations and meteorological parameters, we found that higher concentrations of particulate PAHs in winter resulted from enhanced vehicle exhaust under low temperature and accumulation of pollutants under decreased boundary layer, slower wind speed, and long-term dryness conditions. It is suggested that the typical subtropical monsoon climate in South China, cool and dry in winter, hot and humid in summer, may play a key role in controlling the source seasonality (by enhancing vehicle exhaust in winter, ground evaporation in summer), and hence the ambient concentrations of PAHs in the air.

  15. Characteristics of PAHs in farmland soil and rainfall runoff in Tianjin, China.

    Science.gov (United States)

    Shi, Rongguang; Xu, Mengmeng; Liu, Aifeng; Tian, Yong; Zhao, Zongshan

    2017-10-14

    Rainfall runoff can remove certain amounts of pollutants from contaminated farmland soil and result in a decline in water quality. However, the leaching behaviors of polycyclic aromatic hydrocarbons (PAHs) with rainfall have been rarely reported due to wide variations in the soil compositions, rainfall conditions, and sources of soil PAHs in complex farmland ecosystems. In this paper, the levels, spatial distributions, and composition profiles of PAHs in 30 farmland soil samples and 49 rainfall-runoff samples from the Tianjin region in 2012 were studied to investigate their leaching behaviors caused by rainfall runoff. The contents of the Σ 16 PAHs ranged from 58.53 to 3137.90 μg/kg in the soil and 146.58 to 3636.59 μg/L in the runoff. In total, most of the soil sampling sites (23 of 30) were contaminated, and biomass and petroleum combustion were proposed as the main sources of the soil PAHs. Both the spatial distributions of the soil and the runoff PAHs show a decreasing trend moving away from the downtown, which suggested that the leaching behaviors of PAHs in a larger region during rainfall may be mainly affected by the compounds themselves. In addition, 4- and 5-ring PAHs are the dominant components in farmland soil and 3- and 4-ring PAHs dominate the runoff. Comparisons of the PAH pairs and enrichment ratios showed that acenaphthylene, acenaphthene, benzo[a]anthracene, chrysene, and fluoranthene were more easily transferred into water systems from soil than benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[ghi]perylene, and indeno[123-cd]pyrene, which indicated that PAHs with low molecular weight are preferentially dissolved due to their higher solubility compared to those with high molecular weight.

  16. Monitoring PAH contamination in water: Comparison of biological and physico-chemical tools

    International Nuclear Information System (INIS)

    Bourgeault, A.; Gourlay-Francé, C.

    2013-01-01

    The suitability of biological methods and chemical-based passive samplers to determine exposure to PAHs was tested by deploying zebra mussels and SPMDs along the Seine River over 11 months. The concentration of 13 PAHs was analyzed every month in both water and mussels. The sum of the PAH concentrations in mussels, initially at 299 ng g dry wt −1 , reached 2654, 3972 and 3727 ng g −1 at the end of exposure in the three sampling points taken through the river. The respective SPMD-available concentrations of TPAHs reached 9, 52 and 34 ng L −1 . Results showed seasonal variations of total PAH concentrations in the mussels, characterized by a decrease during spawning. The non-achievement of steady state concentration that was observed in mussels may be accounted for by the temporal variation of environmental concentrations. Thus, a bioaccumulation model based on kinetic rather than simple equilibrium partitioning was found to be more appropriate to describe PAH content in mussels. Moreover, biodynamic kinetic modeling proved useful to better understand the uptake and loss processes of pyrene. It clearly shows that these processes are markedly influenced by the biological state of the zebra mussels. The most realistic hypothesis is that the temporal variation of the biodynamic parameters may originate from a decrease of the mussels' metabolization of PAHs during spawning. Since SPMD passive samplers cannot integrate such biological factors, they are poor predictors of PAH bioavailability in mussels. - Highlights: • PAH contamination was monitored by deploying mussels and SPMDs over 11 months along the Seine River. • 5–6 ring PAHs which could not be quantified in spot samples, were measured in SPMDs. • PAH concentrations in the mussels decreased during spawning. • Temporal variation of bioaccumulated PAH may originate from a decrease of the mussels' metabolism during spawning. • Biodynamic model was allowed to explain the bioaccumulation

  17. Compositional effects on PAH and soot formation in counterflow diffusion flames of gasoline surrogate fuels

    KAUST Repository

    Park, Sungwoo; Wang, Yu; Chung, Suk-Ho; Sarathy, Mani

    2017-01-01

    Gasoline surrogate fuels are widely used to understand the fundamental combustion properties of complex refinery gasoline fuels. In this study, the compositional effects on polycyclic aromatic hydrocarbons (PAHs) and soot formation were investigated experimentally for gasoline surrogate mixtures comprising n-heptane, iso-octane, and toluene in counterflow diffusion flames. A comprehensive kinetic model for the gasoline surrogate mixtures was developed to accurately predict the fuel oxidation along with the formation of PAHs and soot in flames. This combined model was first tested against ignition delay times and laminar burning velocities data. The proposed model for the formation and growth of PAHs up to coronene (C24H12) was based on previous studies and was tested against existing and present new experimental data. Additionally, in the accompanied soot model, PAHs with sizes larger than (including) pyrene were used for the inception of soot particles, followed by particle coagulations and PAH condensation/chemical reactions on soot surfaces. The major pathways for the formation of PAHs were also identified for the surrogate mixtures. The model accurately captures the synergistic PAH formation characteristics observed experimentally for n-heptane/toluene and iso-octane/toluene binary mixtures. Furthermore, the present experimental and modeling results also elucidated different trends in the formation of larger PAHs and soot between binary n-heptane/iso-octane and ternary n-heptane/iso-octane/toluene mixtures. Propargyl radicals (C3H3) were shown to be important in the formation and growth of PAHs for n-heptane/iso-octane mixtures when the iso-octane concentration increased; however, reactions involving benzyl radicals (C6H5CH2) played a significant role in the formation of PAHs for n-heptane/iso-octane/toluene mixtures. These results indicated that the formation of PAHs and subsequently soot was strongly affected by the composition of gasoline surrogate mixtures.

  18. Effect of a cationic surfactant on the volatilization of PAHs from soil.

    Science.gov (United States)

    Lu, Li; Zhu, Lizhong

    2012-06-01

    Cationic surfactants are common in soils because of their use in daily cosmetic and cleaning products, and their use as a soil amendment for the mitigation and remediation of organic contaminated soils has been proposed. Such surfactant may affect the transfer and fate of organic contaminants in the environment. This study investigated the effect of a cationic surfactant, dodecylpyridinium bromide (DDPB), on the volatilization of polycyclic aromatic hydrocarbons (PAHs) from a paddy soil. The volatilization of PAHs from moist soil amended with different concentrations of DDPB was tested in an open system. The specific effects of DDPB on the liquid-vapor and solid-vapor equilibriums of PAHs were separately investigated in closed systems by headspace analysis. DDPB affects both liquid-vapor and solid-vapor processes of PAHs in soil. At DDPB concentrations below the critical micelle concentration (CMC), movement of PAHs from the bulk solution to the gas-liquid interface appeared to be facilitated by interaction between PAHs and the surfactant monomers adsorbed at the gas-liquid interface, promoting the volatilization of PAHs from solution. However, when DDPB was greater than the CMC, volatilization was inhibited due to the solubilization of PAHs by micelles. On the other hand, the formation of sorbed surfactant significantly inhibited the solid-vapor volatilization of PAHs. The overall effect of the two simultaneous effects of DDPB on liquid-vapor and solid-vapor processes was a decreased volatilization loss of PAHs from soil. Inhibition of PAH volatilization was more significant for the soil with a lower moisture content.

  19. Association of plasma IL-6 and Hsp70 with HRV at different levels of PAHs metabolites.

    Directory of Open Access Journals (Sweden)

    Jian Ye

    Full Text Available Exposure to polycyclic aromatic hydrocarbons (PAHs is associated with reduced heart rate variability (HRV, a strong predictor of cardiovascular diseases, but the mechanism is not well understood.We hypothesized that PAHs might induce systemic inflammation and stress response, contributing to altered cardiac autonomic function.HRV indices were measured using a 3-channel digital Holter monitor in 800 coke oven workers. Plasma levels of interleukin-6 (IL-6 and heat shock protein 70 (Hsp70 were determined using ELISA. Twelve urinary PAHs metabolites (OH-PAHs were measured by gas chromatography-mass spectrometry.We found that significant dose-dependent relationships between four urinary OH-PAHs and IL-6 (all Ptrend<0.05; and an increase in quartiles of IL-6 was significantly associated with a decrease in total power (TP and low frequency (LF (Ptrend = 0.014 and 0.006, respectively. In particular, elevated IL-6 was associated in a dose-dependent manner with decreased TP and LF in the high-PAHs metabolites groups (all Ptrend<0.05, but not in the low-PAHs metabolites groups. No significant association between Hsp70 and HRV in total population was found after multivariate adjustment. However, increased Hsp70 was significantly associated with elevated standard deviation of NN intervals (SDNN, TP and LF in the low-PAHs metabolites groups (all Ptrend<0.05. We also observed that both IL-6 and Hsp70 significantly interacted with multiple PAHs metabolites in relation to HRV.In coke oven workers, increased IL-6 was associated with a dose-response decreased HRV in the high-PAHs metabolites groups, whereas increase of Hsp70 can result in significant dose-related increase in HRV in the low-PAHs metabolites groups.

  20. Monitoring PAH contamination in water: Comparison of biological and physico-chemical tools

    Energy Technology Data Exchange (ETDEWEB)

    Bourgeault, A., E-mail: bourgeault@ensil.unilim.fr; Gourlay-Francé, C.

    2013-06-01

    The suitability of biological methods and chemical-based passive samplers to determine exposure to PAHs was tested by deploying zebra mussels and SPMDs along the Seine River over 11 months. The concentration of 13 PAHs was analyzed every month in both water and mussels. The sum of the PAH concentrations in mussels, initially at 299 ng g{sub dry} {sub wt}{sup −1}, reached 2654, 3972 and 3727 ng g{sup −1} at the end of exposure in the three sampling points taken through the river. The respective SPMD-available concentrations of TPAHs reached 9, 52 and 34 ng L{sup −1}. Results showed seasonal variations of total PAH concentrations in the mussels, characterized by a decrease during spawning. The non-achievement of steady state concentration that was observed in mussels may be accounted for by the temporal variation of environmental concentrations. Thus, a bioaccumulation model based on kinetic rather than simple equilibrium partitioning was found to be more appropriate to describe PAH content in mussels. Moreover, biodynamic kinetic modeling proved useful to better understand the uptake and loss processes of pyrene. It clearly shows that these processes are markedly influenced by the biological state of the zebra mussels. The most realistic hypothesis is that the temporal variation of the biodynamic parameters may originate from a decrease of the mussels' metabolization of PAHs during spawning. Since SPMD passive samplers cannot integrate such biological factors, they are poor predictors of PAH bioavailability in mussels. - Highlights: • PAH contamination was monitored by deploying mussels and SPMDs over 11 months along the Seine River. • 5–6 ring PAHs which could not be quantified in spot samples, were measured in SPMDs. • PAH concentrations in the mussels decreased during spawning. • Temporal variation of bioaccumulated PAH may originate from a decrease of the mussels' metabolism during spawning. • Biodynamic model was allowed to explain

  1. Atmospheric versus biological sources of polycyclic aromatic hydrocarbons (PAHs) in a tropical rain forest environment

    International Nuclear Information System (INIS)

    Krauss, Martin; Wilcke, Wolfgang; Martius, Christopher; Bandeira, Adelmar G.; Garcia, Marcos V.B.; Amelung, Wulf

    2005-01-01

    To distinguish between pyrogenic and biological sources of PAHs in a tropical rain forest near Manaus, Brazil, we determined the concentrations of 21 PAHs in leaves, bark, twigs, and stem wood of forest trees, dead wood, mineral topsoil, litter layer, air, and Nasutitermes termite nest compartments. Naphthalene (NAPH) was the most abundant PAH with concentrations of 35 ng m -3 in air (>85% of the Σ21PAHs concentration), up to 1000 μg kg -1 in plants (>90%), 477 μg kg -1 in litter (>90%), 32 μg kg -1 in topsoil (>90%), and 160 μg kg -1 (>55%) in termite nests. In plants, the concentrations of PAHs in general decreased in the order leaves > bark > twigs > stem wood. The concentrations of most low-molecular weight PAHs in leaves and bark were near equilibrium with air, but those of NAPH were up to 50 times higher. Thus, the atmosphere seemed to be the major source of all PAHs in plants except for NAPH. Additionally, phenanthrene (PHEN) had elevated concentrations in bark and twigs of Vismia cayennensis trees (12-60 μg kg -1 ), which might have produced PHEN. In the mineral soil, perylene (PERY) was more abundant than in the litter layer, probably because of in situ biological production. Nasutitermes nests had the highest concentrations of most PAHs in exterior compartments (on average 8 and 15 μg kg -1 compared to -1 in interior parts) and high PERY concentrations in all compartments (12-86 μg kg -1 ), indicating an in situ production of PERY in the nests. Our results demonstrate that the deposition of pyrolytic PAHs from the atmosphere controls the concentrations of most PAHs. However, the occurrence of NAPH, PHEN, and PERY in plants, termite nests, and soils at elevated concentrations supports the assumption of their biological origin. - Evidence of non-pyrolytic, biogenic production of PAHs is provided

  2. Enhanced bioremediation of PAH-contaminated soil by immobilized bacteria with plant residue and biochar as carriers

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Baoliang; Yuan, Miaoxin; Qian, Linbo [Zhejiang Univ., Hangzhou (China). Dept. of Environmental Science; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou (China)

    2012-10-15

    Polycyclic aromatic hydrocarbons (PAHs) are largely accumulated in soils in China. The immobilized-microorganism technique (IMT) is a potential approach for abating soil contamination with PAHs. However, few studies about the application of IMT to contaminated soil remediation were reported. Due to recalcitrance to decomposition, biochar application to soil may enhance soil carbon sequestration, but few studies on the application of biochars to remediation of contaminated soil were reported. In this study, we illustrated enhanced bioremediation of soil having a long history of PAH contamination by IMT using plant residues and biochars as carriers. Two PAH-degrading bacteria, Pseudomonas putida and an unidentified indigenous bacterium, were selected for IMT. The extractability and biodegradation of 15 PAHs in solution and an actual PAH-contaminated soil amended with immobilized-bacteria materials were investigated under different incubation periods. The effects of carriers and the molecular weight of PAHs on bioremediation efficiency were determined to illustrate their different bio-dissipation mechanisms of PAHs in soil. The IMT can considerably enhance the removal of PAHs. Carriers impose different effects on PAH bio-dissipation by amended soil with immobilized-bacteria, which can directly degrade the carrier-associated PAHs. The removal of PAHs from soil depended on PAH molecular weight and carrier types. Enhanced bio-dissipation by IMT was much stronger for 4- and 5-ring PAHs than for 3- and 6-ring ones in soil. Only P400 biochar-immobilized bacteria enhanced bio-dissipation of all PAHs in contaminated soil after a 90-day incubation. Biochar can promote bioremediation of contaminated soil as microbial carriers of IMT. It is vital to select an appropriate biochar as an immobilized carrier to stimulate biodegradation. It is feasible to use adsorption carriers with high sorptive capabilities to concentrate PAHs as well as microorganisms and thereby enhance

  3. Supplementary measurements for air monitoring under NOVANA - Benzene and PAH; Supplerende maalinger til luftovervaagning under NOVANA - benzen og PAH

    Energy Technology Data Exchange (ETDEWEB)

    Ellermann, T.; Klenoe Noejgaard, J.; Bossi, R.

    2011-10-15

    The report presents results from a project carried out for the Danish Environmental Protection Agency. The aim of the project was to carry out several measuring campaigns in order to be able to better assess the monitoring needs for PAH and benzene in relation to EU's air quality directives. The results show that the mean concentrations of benzene are almost at the same level in Denmark's four largest cities, and that the concentrations are both below the threshold value (5mug/m3) as well as below the lower assessment threshold (2mug/m3). The report presents a method for objectively estimation the benzene concentration based on measurements of CO. The method can be applied to fulfil the monitoring need for benzene in those zones where no measurements of benzene are made. Measurements of PAH, especially benzo(a)pyrene, have been made during 12 months in the period 2010-2011 in an area with many wood burning furnaces are used (the town Jyllinge). The concentrations of benzo(a)pyrene in Jyllinge is almost three times higher than in the street H.C. Andersens Boulevard in Copenhagen. The concentrations of benzo(a)pyrene in Jylllinge are 0,6 ng/m3, which corresponds to the upper assessment threshold (0,6 ng/m3) and is 40% below the measuring value (1 ng/m3). On this basis, there is a need for re-evaluating the monitoring of PAH in the sub-programme for air under NOVANA. Measurements of PM{sub 10} showed that the levels in the towns Jyllinge, Lille Valby/Risoe and at the H.C. Oersted Institute in Copenhagen are all at about 20-22 mug/m3. (LN)

  4. Biomonitoring airborne parent and alkylated three-ring PAHs in the Greater Cologne Conurbation I: Temporal accumulation patterns

    International Nuclear Information System (INIS)

    Lehndorff, E.; Schwark, L.

    2009-01-01

    Polycyclic aromatic hydrocarbons (PAHs) comprise an important group of air pollutants, with three-ring components (PAH-3) often dominating. Spatiotemporal variation in atmospheric PAH-3 can be analyzed by biomonitoring but high vapour pressure and low octanol-air-partitioning of PAH-3 cause dynamic accumulation on plant surfaces. This study for the first time shows that PAH-3 exhibit systematic accumulation trends on pine needles of 3-48 months of exposure time at six sites in Germany. Correlation of needle exposure time with PAH-3 concentration was r 2 = 0.83 for phenanthrene and methylphenanthrenes, r 2 = 0.77 for cyclopenta[def]phenanthrene, r 2 = 0.60 for dibenzothiophene, r 2 = 0.57 for dimethylphenanthrenes and r 2 = 0.32 for retene. Variations in PAH-3 for summer and winter collected needles emphasize vegetation-air-partitioning influence on cumulative PAH-3 loads. PAH-3 ratios calculated for needle cohorts indicate persistence of original PAH patterns thus demonstrating the source-diagnostic potential of pine needle biomonitoring, which is utilized in part II of this study where spatial distribution of PAH-3 is investigated and related to emission sources. - Accumulation of volatile three-ring PAHs on pine needles was found to be systematic over a period of 50 months thus qualifying PAHs for regional air quality studies

  5. PAH clearance after renal ischemia and reperfusion is a function of impaired expression of basolateral Oat1 and Oat3.

    Science.gov (United States)

    Bischoff, Ariane; Bucher, Michael; Gekle, Michael; Sauvant, Christoph

    2014-02-01

    Determination of renal plasma flow (RPF) by para-aminohippurate (PAH) clearance leads to gross underestimation of this respective parameter due to impaired renal extraction of PAH after renal ischemia and reperfusion injury. However, no mechanistic explanation for this phenomenon is available. Based on our own previous studies we hypothesized that this may be due to impairment of expression of the basolateral rate limiting organic anion transporters Oat1 and Oat3. Thus, we investigated this phenomenon in a rat model of renal ischemia and reperfusion by determining PAH clearance, PAH extraction, PAH net secretion, and the expression of rOat1 and rOat3. PAH extraction was seriously impaired after ischemia and reperfusion which led to a threefold underestimation of RPF when PAH extraction ratio was not considered. PAH extraction directly correlated with the expression of basolateral Oat1 and Oat3. Tubular PAH secretion directly correlated with PAH extraction. Consequently, our data offer an explanation for impaired renal PAH extraction by reduced expression of the rate limiting basolateral organic anion transporters Oat1 and Oat3. Moreover, we show that determination of PAH net secretion is suitable to correct PAH clearance for impaired extraction after ischemia and reperfusion in order to get valid results for RPF.

  6. Biomonitoring airborne parent and alkylated three-ring PAHs in the Greater Cologne Conurbation I: Temporal accumulation patterns

    Energy Technology Data Exchange (ETDEWEB)

    Lehndorff, E. [Department of Geology and Mineralogy, University of Cologne, Zuelpicher Str. 49a, 50674 Cologne (Germany); Schwark, L. [Department of Geology and Mineralogy, University of Cologne, Zuelpicher Str. 49a, 50674 Cologne (Germany); Institute of Geosciences, Kiel University, Ludewig-Meyn-Str. 10, 24118 Kiel (Germany)], E-mail: ls@gpi.uni-kiel.de

    2009-04-15

    Polycyclic aromatic hydrocarbons (PAHs) comprise an important group of air pollutants, with three-ring components (PAH-3) often dominating. Spatiotemporal variation in atmospheric PAH-3 can be analyzed by biomonitoring but high vapour pressure and low octanol-air-partitioning of PAH-3 cause dynamic accumulation on plant surfaces. This study for the first time shows that PAH-3 exhibit systematic accumulation trends on pine needles of 3-48 months of exposure time at six sites in Germany. Correlation of needle exposure time with PAH-3 concentration was r{sup 2} = 0.83 for phenanthrene and methylphenanthrenes, r{sup 2} = 0.77 for cyclopenta[def]phenanthrene, r{sup 2} = 0.60 for dibenzothiophene, r{sup 2} = 0.57 for dimethylphenanthrenes and r{sup 2} = 0.32 for retene. Variations in PAH-3 for summer and winter collected needles emphasize vegetation-air-partitioning influence on cumulative PAH-3 loads. PAH-3 ratios calculated for needle cohorts indicate persistence of original PAH patterns thus demonstrating the source-diagnostic potential of pine needle biomonitoring, which is utilized in part II of this study where spatial distribution of PAH-3 is investigated and related to emission sources. - Accumulation of volatile three-ring PAHs on pine needles was found to be systematic over a period of 50 months thus qualifying PAHs for regional air quality studies.

  7. Dry Deposition of Polycyclic Aromatic Hydrocarbons (PAHs) at a Suburban Site in Beijing, China

    Science.gov (United States)

    Zhang, Xincheng; Wang, Weiyu; Zhu, Xianlei

    2017-04-01

    A great amount of polycyclic aromatic hydrocarbons (PAHs) have been generated by industrial production, waste incineration and landfill, traffic and road dust etc. They are emitted into atmosphere and afterwards enter into water body and soil through deposition, resulting in wide distribution of PAHs in environment. However, the dry deposition of PAHs from atmosphere has not been well studied, especially in the aspects of its characteristics, environmental and health effects, sources and mechanism. This study measured PAHs dry deposition in the northwest suburban area of Beijing. Dry deposition samples (i.e. dustfall samples) were collected at the sampling site located in China University of Petroleum - Beijing in 2012-2016. And PAHs in the samples were determined by GC/MS. The dry deposition flux of 16 US EPA priority PAHsPAH16) was 2.58 μg/(m^2·d), which was lower than those in other regions of North China. Its seasonal variability was more significant than annual variability (p spring > autumn > summer. The amount of ΣPAH16 removed from the atmosphere by dry deposition process accounted for only 1.2% of their emissions, indicating that the atmosphere self-purification capacity was quite limited and emission reduction measures would play a key role in controlling PAHs air pollution. However, PAHs dry deposition would deteriorate soil quality since the content of ΣPAH16 in dustfall was 1-2 orders of magnitude higher than that in soil in the same area. Dermal exposure resulting from PAHs dry deposition was not the major route. The sources of PAHs dry deposition varied with seasons. The profile and specific ratios of PAHs showed that in winter, domestic coal combustion was the main source of PAHs with the contribution up to 77%; in spring and summer, the impact of coal combustion decreased and the contribution of vehicle exhaust increased to 30% - 45%; in fall, in addition to coal combustion and vehicle exhaust, the impact of biomass burning was observed

  8. Androgen excess: Investigations and management.

    Science.gov (United States)

    Lizneva, Daria; Gavrilova-Jordan, Larisa; Walker, Walidah; Azziz, Ricardo

    2016-11-01

    Androgen excess (AE) is a key feature of polycystic ovary syndrome (PCOS) and results in, or contributes to, the clinical phenotype of these patients. Although AE will contribute to the ovulatory and menstrual dysfunction of these patients, the most recognizable sign of AE includes hirsutism, acne, and androgenic alopecia or female pattern hair loss (FPHL). Evaluation includes not only scoring facial and body terminal hair growth using the modified Ferriman-Gallwey method but also recording and possibly scoring acne and alopecia. Moreover, assessment of biochemical hyperandrogenism is necessary, particularly in patients with unclear or absent hirsutism, and will include assessing total and free testosterone (T), and possibly dehydroepiandrosterone sulfate (DHEAS) and androstenedione, although these latter contribute limitedly to the diagnosis. Assessment of T requires use of the highest quality assays available, generally radioimmunoassays with extraction and chromatography or mass spectrometry preceded by liquid or gas chromatography. Management of clinical hyperandrogenism involves primarily either androgen suppression, with a hormonal combination contraceptive, or androgen blockade, as with an androgen receptor blocker or a 5α-reductase inhibitor, or a combination of the two. Medical treatment should be combined with cosmetic treatment including topical eflornithine hydrochloride and short-term (shaving, chemical depilation, plucking, threading, waxing, and bleaching) and long-term (electrolysis, laser therapy, and intense pulse light therapy) cosmetic treatments. Generally, acne responds to therapy relatively rapidly, whereas hirsutism is slower to respond, with improvements observed as early as 3 months, but routinely only after 6 or 8 months of therapy. Finally, FPHL is the slowest to respond to therapy, if it will at all, and it may take 12 to 18 months of therapy for an observable response. Copyright © 2016. Published by Elsevier Ltd.

  9. Natural organic matter to enhance electrokinetic transport of PAH

    Energy Technology Data Exchange (ETDEWEB)

    Suer, P.; Joensson, S.; Allard, B. [Man-Technology-Environment Research Centre, Oerebro Univ. (Sweden)

    2001-07-01

    The remediation of contaminated soil can be enhanced with natural organic matter (NOM) as a complexing agent for pollutants. NOM has both hydrophobic and acidic properties, so that it is charged and thus subject to electroremediation. At the same time many contaminants have a high affinity for organic matter. Organic matter was produced in situ in an electric field or added in solute form. The resulting dissolved organic matter was transported towards the cathode, probably by cationic colloids. Produced dissolved organic matter included high molecular weight molecules near the cathode, at the site of pH buffering. Pyrene and phenanthrene were likewise transported towards the cathode. Movement was small but distinctive in 2-day experiments. Clay influence the soil/water distribution of the PAH but no effect on the total transport could be discerned. The presence of solid organic matter in the soil removed all PAH from the water phase, even though the concentration of organic matter in the water phase was high as well. (orig.)

  10. Development of the Pulmonary Arterial Hypertension-Symptoms and Impact (PAH-SYMPACT®) questionnaire: a new patient-reported outcome instrument for PAH.

    Science.gov (United States)

    McCollister, Deborah; Shaffer, Shannon; Badesch, David B; Filusch, Arthur; Hunsche, Elke; Schüler, René; Wiklund, Ingela; Peacock, Andrew

    2016-06-14

    Regulators and clinical experts increasingly recognize the importance of incorporating patient-reported outcomes (PROs) in clinical studies of therapies for pulmonary arterial hypertension (PAH). No PAH-specific instruments have been developed to date in accordance with the 2009 FDA guidance for the development of PROs as endpoints in clinical trials. A qualitative research study was conducted to develop a new instrument assessing PAH symptoms and their impacts following the FDA PRO guidance. A cross-sectional study was conducted at 5 centers in the US in symptomatic PAH patients aged 18-80 years. Concept elicitation was based on 5 focus group discussions, after which saturation of emergent concepts was reached. A PRO instrument for PAH symptoms and their impacts was drafted. To assess the appropriateness of items, instructions, response options, and recall periods, 2 rounds of one-on-one cognitive interviews were conducted, with instrument revisions following each round. Additional interviews tested the usability of an electronic version (ePRO). PRO development considered input from an international Steering Committee, and translatability and lexibility assessments. Focus groups comprised 25 patients (5 per group); 20 additional patients participated in cognitive interviews (10 per round); and 10 participated in usability interviews. Participants had a mean ± SD age of 53.1 ± 15.8 years, were predominantly female (93 %), and were diverse in race/ethnicity, WHO functional class (FC I/II: 56 %, III/IV: 44 %), and PAH etiology (idiopathic: 56 %, familial: 2 %, associated: 42 %). The draft PRO instrument (PAH-SYMPACT®) was found to be clear, comprehensive, and relevant to PAH patients in cognitive interviews. Items were organized in a draft conceptual framework with 16 symptom items in 4 domains (respiratory symptoms, tiredness, cardiovascular symptoms, other symptoms) and 25 impact items in 5 domains (physical activities, daily activities, social

  11. Development of methods for determination of PAH based on measured CO-content; Metodutveckling foer indirekt bestaemning av PAH-halt utgaaende fraan maett momentan CO-halt

    Energy Technology Data Exchange (ETDEWEB)

    Ingman, Rolf; Schuster, Robert [AaF Energikonsult Stockholm AB, Stockholm (Sweden)

    2001-02-01

    The aim of the project 'Development of methods for determination of PAH based on measured CO-content' is to investigate the possibility to develop a method for continuous optimisation of NO{sub x}-emissions by decreased air ratio, without significant increase of polyaromatic hydrocarbons such as PAH. The general idea has been to find a indirect online method to predict the emissions of heavier hydrocarbons by: - creating a correlation between the content of CO and PAH, - controlling the air ratio by the CO-content, and - integrating the calculated PAH-content from CO-content. Today many boilers are operated with a low air ratio to minimise the NO{sub x} content and the NO{sub x}-fee. A low ratio increases the risk of high CO contents in the flue gas as well as increased contents of VOC and PAH. Other boilers are operated with high air ratios in order to minimise the CO content, which in some cases will result in unnecessary high NO{sub x} emissions. One of the main difficulties in optimising the air ratio to the most environmental friendly level is the lack of a suitable and well proven PAH instrument. There are today no available instruments for instantaneous and continuous measurement of PAH. PAH is normally measured as an average value during a period of at least one hour. It is not possible to detect short peaks. The development of the CO-method has been based on data from a CFB-boiler in Korsta in Sundsvall (Vaermeforskrapport 541). The data shows a clear correlation between THC and CO. The correlation seems to be mostly dependent of moisture content and load. The development presented in the report shows that it is possible to find a method to predict the PAH content from the CO-content in the flue gas. The next phase aims to improve and implement the method, by measurements and adaptation in a plant. The practical use of the method is as a tool to optimise the emission of CO, NO{sub x}, THC and PAH and/or to predict the PAH-emission during

  12. Source characterisation and distribution of selected PCBs, PAHs and alkyl PAHs in sediments from the Klip and Jukskei Rivers, South Africa.

    Science.gov (United States)

    Rimayi, Cornelius; Chimuka, Luke; Odusanya, David; de Boer, Jacob; Weiss, Jana M

    2017-07-01

    A study of the distribution of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) utilising 16 priority PAHs, benzo(e)pyrene, perylene, 19 alkylated PAHs and 31 ortho substituted PCBs in South Africa is presented. It was aimed to (a) deduce characteristic contamination patterns for both PCBs and PAHs and (b) provide the first comprehensive dataset for establishment of source characterisation of PCBs and PAHs. This is in line with new South African legislation on mandatory monitoring of PCB and PAH emissions. Bar charts, principal component analysis (PCA) and biplots were utilised to identify signature contamination patterns and distribution of PCBs and PAHs within the Jukskei and Klip Rivers. Sediments from the Jukskei and Klip River catchments both showed distinct contamination signatures for hexa to nonachlorinated PCBs, characteristic of contamination by Aroclor 1254 and 1260 technical mixtures. PCB signature patterns in order of abundance were 138 > 180 > 206 > 153 > 187 > 149 and 138 > 153 > 180 > 149 > 187 > 110 > 170 for the Jukskei and Klip River sediments, respectively. The upstream Alberton point had the highest Σ31 PCB and Σ (parent+alkyl) PAH concentrations in the Klip River of 61 and 6000 μg kg -1 dry weight (dw), respectively. In the Jukskei River, the upstream Marlboro point had the highest Σ31 PCB concentration of 19 μg kg -1 dw and the N14 site recorded the highest Σ (parent+alkyl) PAH concentration of 2750 μg kg -1 dw. PAH concentrations in both the Jukskei and Klip Rivers were significantly higher than the PCB concentrations. Fluoranthene, phenanthrene and pyrene were found in the highest concentrations in both the Jukskei and Klip River sediments. Both the Jukskei and Klip River sediments showed trends of a mixed pyrogenic-petrogenic PAH source contamination.

  13. Coal-tar-based pavement sealcoat, polycyclic aromatic Hydrocarbons (PAHs), and environmental health

    Science.gov (United States)

    Mahler, B.J.; Van Metre, P.C.

    2011-01-01

    Studies by the U.S. Geological Survey (USGS) have identified coal-tar-based sealcoat-the black, viscous liquid sprayed or painted on asphalt pavement such as parking lots-as a major source of polycyclic aromatic hydrocarbon (PAH) contamination in urban areas for large parts of the Nation. Several PAHs are suspected human carcinogens and are toxic to aquatic life.

  14. Investigation of the release of PAHs from artificially contaminated sediments using cyclolipopeptidic biosurfactants.

    Science.gov (United States)

    Portet-Koltalo, F; Ammami, M T; Benamar, A; Wang, H; Le Derf, F; Duclairoir-Poc, C

    2013-10-15

    Polycyclic aromatic hydrocarbons (PAHs) can be preponderant in contaminated sediments and understanding how they are sorbed in the different mineral and organic fractions of the sediment is critical for effective removal strategies. For this purpose, a mixture of seven PAHs was studied at the sediment/water interface and sorption isotherms were obtained. The influence of various factors on the sorption behavior of PAHs was evaluated, such as the nature of minerals, pH, ionic strength and amount of organic matter. Afterwards, the release of PAHs from the sediment by surfactants was investigated. The effectiveness of sodium dodecyl sulfate (SDS) was compared to natural biosurfactants, of cyclolipopeptidic type (amphisin and viscosin-like mixture), produced by two Pseudomonas fluorescens strains. The desorption of PAHs (from naphthalene to pyrene), from the highly retentive kaolinite fraction, could be favored by adding SDS or amphisin, but viscosin-like biosurfactants were only effective for 2-3 ring PAHs desorption (naphthalene to phenanthrene). Moreover, while SDS favors the release of all the target PAHs from a model sediment containing organic matter, the two biosurfactants tested were only effective to desorb the lowest molecular weight PAHs (naphthalene to fluorene). Copyright © 2013 Elsevier B.V. All rights reserved.

  15. 1-Hydroxypyrene as a biomarker of PAH exposure in the marine polychaete Nereis diversicolor

    DEFF Research Database (Denmark)

    Tairova, Zhanna; Giessing, Anders; Hansen, Rikke

    2009-01-01

    The possibility of using the pyrene metabolite I-hydroxypyrene as a biomarker of polycyclic aromatic hydrocarbons (PAHs) exposure was investigated by exposure of the marine polychaete Nereis diversicolor to several PAHs in the laboratory. Animals were exposed to pyrene alone and to five different...

  16. Remediation technologies for treatment of PAH contaminated soil and strategies to enhance process efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, J.; Alcantara, M. T.; Pazos, M.; Longo, M. A.; Sanroman, M. A.

    2009-07-01

    The presence of carcinogenic polycyclic aromatic hydrocarbons (PAHs) in soils poses a potential threat to human health. The removal of these contaminants presents a challenge to scientists and engineers. PAHs are characterized by their palpable hydrophobic nature. Consequently, these species tend to be adsorbed on solid particulates, especially on the organic fraction of the solids. (Author)

  17. Remediation technologies for treatment of PAH contaminated soil and strategies to enhance process efficiency

    International Nuclear Information System (INIS)

    Gomez, J.; Alcantara, M. T.; Pazos, M.; Longo, M. A.; Sanroman, M. A.

    2009-01-01

    The presence of carcinogenic polycyclic aromatic hydrocarbons (PAHs) in soils poses a potential threat to human health. The removal of these contaminants presents a challenge to scientists and engineers. PAHs are characterized by their palpable hydrophobic nature. Consequently, these species tend to be adsorbed on solid particulates, especially on the organic fraction of the solids. (Author)

  18. Increased zooplankton PAH concentrations across hydrographic fronts in the East China Sea.

    Science.gov (United States)

    Hung, Chin-Chang; Ko, Fung-Chi; Gong, Gwo-Ching; Chen, Kuo-Shu; Wu, Jian-Ming; Chiang, Hsin-Lun; Peng, Sen-Chueh; Santschi, Peter H

    2014-06-15

    The Changjiang has transported large quantities of polycyclic aromatic hydrocarbons (PAHs) to the East China Sea (ECS), but information of these pollutants in zooplankton is limited. To understand PAHs pollution in zooplankton in the ECS, total concentrations of PAHs in zooplankton from surface waters were measured. Values of PAHs ranged from 2 to 3500 ng m(-3) in the ECS, with highest PAHs levels located at the salinity front between the Changjiang Diluted Water (CDW) and the mid-shelf waters. In contrast, concentrations of zooplankton PAHs in the mid-shelf and outer-shelf waters were significantly lower (2-23 ng m(-3)) than those in the CDW. These results demonstrate that PAHs are conspicuously accumulated in zooplankton at the salinity front between the CDW and the mid-shelf waters. These higher levels of PAHs in zooplankton at the salinity front may be further biomagnified in marine organisms of higher trophic levels through their feeding activities. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  19. Occurrence of Nitro-PAH in the Atmosphere in a Rural Area

    DEFF Research Database (Denmark)

    Nielsen, Tom; Seitz, B.; Ramdahl, T.

    1984-01-01

    -(a)pyrene have been identied in samples of airborne particulate matter. Furthermore, 8-nitrofluoranthene has been tentatively identified. The amounts of mononitro-PAH are one to two orders of magnitude lower than the most common carcinogenic PAH, as e.g. benzo(a)pyrene. Filter effects have been studied, 9...

  20. A directional passive air sampler for monitoring polycyclic aromatic hydrocarbons (PAHs) in air mass

    International Nuclear Information System (INIS)

    Tao, S.; Liu, Y.N.; Lang, C.; Wang, W.T.; Yuan, H.S.; Zhang, D.Y.; Qiu, W.X.; Liu, J.M.; Liu, Z.G.; Liu, S.Z.; Yi, R.; Ji, M.; Liu, X.X.

    2008-01-01

    A passive air sampler was developed for collecting polycyclic aromatic hydrocarbons (PAHs) in air mass from various directions. The airflow velocity within the sampler was assessed for its responses to ambient wind speed and direction. The sampler was examined for trapped particles, evaluated quantitatively for influence of airflow velocity and temperature on PAH uptake, examined for PAH uptake kinetics, calibrated against active sampling, and finally tested in the field. The airflow volume passing the sampler was linearly proportional to ambient wind speed and sensitive to wind direction. The uptake rate for an individual PAH was a function of airflow velocity, temperature and the octanol-air partitioning coefficient of the PAH. For all PAHs with more than two rings, the passive sampler operated in a linear uptake phase for three weeks. Different PAH concentrations were obtained in air masses from different directions in the field test. - A novel directional passive air sampler was developed and tested for monitoring PAHs in air masses from different directions

  1. Mechanism-Based Classification of PAH Mixtures to Predict Carcinogenic Potential.

    Science.gov (United States)

    Tilton, Susan C; Siddens, Lisbeth K; Krueger, Sharon K; Larkin, Andrew J; Löhr, Christiane V; Williams, David E; Baird, William M; Waters, Katrina M

    2015-07-01

    We have previously shown that relative potency factors and DNA adduct measurements are inadequate for predicting carcinogenicity of certain polycyclic aromatic hydrocarbons (PAHs) and PAH mixtures, particularly those that function through alternate pathways or exhibit greater promotional activity compared to benzo[a]pyrene (BaP). Therefore, we developed a pathway-based approach for classification of tumor outcome after dermal exposure to PAH/mixtures. FVB/N mice were exposed to dibenzo[def,p]chrysene (DBC), BaP, or environmental PAH mixtures (Mix 1-3) following a 2-stage initiation/promotion skin tumor protocol. Resulting tumor incidence could be categorized by carcinogenic potency as DBC > BaP = Mix2 = Mix3 > Mix1 = Control, based on statistical significance. Gene expression profiles measured in skin of mice collected 12 h post-initiation were compared with tumor outcome for identification of short-term bioactivity profiles. A Bayesian integration model was utilized to identify biological pathways predictive of PAH carcinogenic potential during initiation. Integration of probability matrices from four enriched pathways (P PAH mixtures. These data further provide a 'source-to-outcome' model that could be used to predict PAH interactions during tumorigenesis and provide an example of how mode-of-action-based risk assessment could be employed for environmental PAH mixtures. © The Author 2015. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  2. MANAGEMENT OF PAH-IMPACTED SITES VIA IN SITU CHEMICAL CONTAINMENT AND MONITORING

    Science.gov (United States)

    On a world-wide basis the magnitude of environmental contamination problems involving polycyclic aromatic hydrocarbon (PAHs) is unmatched by any other group of organic chemicals. Despite the recognized limitations to PAH biodegradation (e.g., intrinsic chemical stability of the h...

  3. Polycyclic aromatic hydrocarbons (PAH) formation from the pyrolysis of different municipal solid waste fractions.

    Science.gov (United States)

    Zhou, Hui; Wu, Chunfei; Onwudili, Jude A; Meng, Aihong; Zhang, Yanguo; Williams, Paul T

    2015-02-01

    The formation of 2-4 ring polycyclic aromatic hydrocarbons (PAH) from the pyrolysis of nine different municipal solid waste fractions (xylan, cellulose, lignin, pectin, starch, polyethylene (PE), polystyrene (PS), polyvinyl chloride (PVC), and polyethylene terephthalate (PET)) were investigated in a fixed bed furnace at 800 °C. The mass distribution of pyrolysis was also reported. The results showed that PS generated the most total PAH, followed by PVC, PET, and lignin. More PAH were detected from the pyrolysis of plastics than the pyrolysis of biomass. In the biomass group, lignin generated more PAH than others. Naphthalene was the most abundant PAH, and the amount of 1-methynaphthalene and 2-methynaphthalene was also notable. Phenanthrene and fluorene were the most abundant 3-ring PAH, while benzo[a]anthracene and chrysene were notable in the tar of PS, PVC, and PET. 2-ring PAH dominated all tar samples, and varied from 40 wt.% to 70 wt.%. For PS, PET and lignin, PAH may be generated directly from the aromatic structure of the feedstock. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Remarkably constant PAH concentrations in Swiss soils over the last 30 years.

    Science.gov (United States)

    Gubler, Andreas; Wächter, Daniel; Blum, Franziska; Bucheli, Thomas D

    2015-10-01

    Although polycyclic aromatic hydrocarbons (PAH) are of concern due to their carcinogenic, mutagenic, and teratogenic properties and their ubiquitous occurrence in environmental compartments, only few studies assessed the temporal evolutions of PAH contents of soils over extended time periods. The Swiss Soil Monitoring Network NABO runs long-term monitoring sites resampled every five years since the 1980s. In the present study, soil (0-20 cm) samples collected from 1985 through 2013 at 25 selected monitoring sites were analysed for the 16 priority PAH according to the U.S. EPA and five PAH marker substances. We observed divergent trends for light PAH, such as naphthalene and phenanthrene, compared with heavy PAH, such as benzo[a]pyrene and benzo[ghi]perylene. Whereas the former showed decreasing concentrations since the late 1980s, no significant trends were found for the latter. Furthermore, the analyses showed that naphthalene contents decreased most strongly at rural sites featuring low population densities, while phenanthrene contents generally decreased most strongly at semi-rural sites. The deviating evolutions of light and heavy PAH were mainly attributed to their differing physico-chemical properties. Temporal evolutions in soils contradict emission inventory data suggesting PAH emissions to decline since the 1980s.

  5. Coal-tar-based parking lot sealcoat: An unrecognized source of PAH to settled house dust

    Science.gov (United States)

    Mahler, B.J.; Van Metre, P.C.; Wilson, J.T.; Musgrove, M.; Burbank, T.L.; Ennis, T.E.; Bashara, T.J.

    2010-01-01

    Despite much speculation, the principal factors controlling concentrations of polycyclic aromatic hydrocarbons (PAH) in settled house dust (SHD) have not yet been identified. In response to recent reports that dust from pavement with coaltar-based sealcoat contains extremely high concentrations of PAH, we measured PAH in SHD from 23 apartments and in dust from their associated parking lots, one-half of which had coal-tar-based sealcoat (CT). The median concentration of total PAH (T-PAH) in dust from CT parking lots (4760 ??g/g, n = 11) was 530 times higher than that from parking lots with other pavement surface types (asphalt-based sealcoat, unsealed asphalt, concrete [median 9.0 ??g/g, n = 12]). T-PAH in SHD from apartments with CT parking lots (median 129 ??g/g) was 25 times higher than that in SHD from apartments with parking lots with other pavement surface types (median 5.1 ??g/g). Presence or absence of CT on a parking lot explained 48% of the variance in log-transformed T-PAH in SHD. Urban land-use intensity near the residence also had a significant but weaker relation to T-PAH. No other variables tested, including carpeting, frequency of vacuuming, and indoor burning, were significant. ?? 2010 American Chemical Society.

  6. Coal-tar-based sealcoated pavement: a major PAH source to urban stream sediments.

    Science.gov (United States)

    Witter, Amy E; Nguyen, Minh H; Baidar, Sunil; Sak, Peter B

    2014-02-01

    We used land-use analysis, PAH concentrations and assemblages, and multivariate statistics to identify sediment PAH sources in a small (~1303 km(2)) urbanizing watershed located in South-Central, Pennsylvania, USA. A geographic information system (GIS) was employed to quantify land-use features that may serve as PAH sources. Urban PAH concentrations were three times higher than rural levels, and were significantly and highly correlated with combined residential/commercial/industrial land use. Principal components analysis (PCA) was used to group sediments with similar PAH assemblages, and correlation analysis compared PAH sediment assemblages to common PAH sources. The strongest correlations were observed between rural sediments (n = 7) and coke-oven emissions sources (r = 0.69-0.78, n = 5), and between urban sediments (n = 22) and coal-tar-based sealcoat dust (r = 0.94, n = 47) suggesting that coal-tar-based sealcoat is an important urban PAH source in this watershed linked to residential and commercial/industrial land use. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Polycyclic Aromatic Hydrocarbons (PAH) in Danish Smoked Fish and Meat Products

    DEFF Research Database (Denmark)

    Duedahl-Olesen, Lene; White, S.; Binderup, Mona-Lise

    2006-01-01

    Twenty seven PAH were detected in 45 selected smoked food samples produced in Denmark, including mackerel, herring, trout, small sausages, salami, and bacon. The sum of PAH in smoked meat products ranged from 24 mu g/kg for salami to 64 mu g/kg in bacon, while those in fish products ranged from 2...

  8. Source apportionment of polycyclic aromatic hydrocarbons (PAHs) in sediments from Khuzestan province, Iran

    DEFF Research Database (Denmark)

    Lübeck, Josephine; Poulsen, Kristoffer Gulmark; Knudsen, Sofie B.

    2016-01-01

    of polycyclic aromatic hydrocarbon (PAH) pollution. A four-component principal component analysis (PCA) model was obtained. While principal component 1 (PC1) was related to the total concentration of PAHs, the remaining PCs described three distinct sources: PC2 and PC3 collectively differentiate between...

  9. FATE OF PAH COMPOUNDS IN TWO SOIL TYPES: INFLUENCE OF VOLATILIZATION, ABIOTIC LOSS, AND BIOLOGICAL ACTIVITY

    Science.gov (United States)

    The fate of 14 polycyclic aromatic hydrocarbon (PAH) compounds was evaluated with regard to interphase transfer potential and mechanisms of treatment in soil under unsaturated conditions. Volatilization and abiotic and biotic fate of the PAHs were determined using two soils not p...

  10. Health implications of PAH release from coated cast iron drinking water distribution systems in The Netherlands.

    Science.gov (United States)

    Blokker, E J Mirjam; van de Ven, Bianca M; de Jongh, Cindy M; Slaats, P G G Nellie

    2013-05-01

    Coal tar and bitumen have been historically used to coat the insides of cast iron drinking water mains. Polycyclic aromatic hydrocarbons (PAHs) may leach from these coatings into the drinking water and form a potential health risk for humans. We estimated the potential human cancer risk from PAHs in coated cast iron water mains. In a Dutch nationwide study, we collected drinking water samples at 120 locations over a period of 17 days under various operational conditions, such as undisturbed operation, during flushing of pipes, and after a mains repair, and analyzed these samples for PAHs. We then estimated the health risk associated with an exposure scenario over a lifetime. During flushing, PAH levels frequently exceeded drinking water quality standards; after flushing, these levels dropped rapidly. After the repair of cast iron water mains, PAH levels exceeded the drinking water standards for up to 40 days in some locations. The estimated margin of exposure for PAH exposure through drinking water was > 10,000 for all 120 measurement locations, which suggests that PAH exposure through drinking water is of low concern for consumer health. However, factors that differ among water systems, such as the use of chlorination for disinfection, may influence PAH levels in other locations.

  11. Origin and Distribution of PAHs in Ambient Particulate Samples at High Mountain Region in Southern China

    Directory of Open Access Journals (Sweden)

    Peng-hui Li

    2015-01-01

    Full Text Available To understand the deposition and transport of PAHs in southern China, a measurement campaign was conducted at a high-elevation site (the summit of Mount Heng, 1269 m A.S.L. from April 4 to May 31, 2009, and a total of 39 total suspended particulate samples were collected for measurement of PAH concentrations. The observed particulate-bound PAHs concentrations ranged from 1.63 to 29.83 ng/m3, with a mean concentration of 6.03 ng/m3. BbF, FLA, and PYR were the predominant compounds. Good correlations were found between individual PAHs and meteorological parameters such as atmospheric pressure, relative humidity, and ambient temperature. The backward trajectory analysis suggested that particulate samples measured at the Mount Heng region were predominantly associated with the air masses from southern China, while the air masses transported over northern and northwestern China had relative higher PAHs concentrations. Based on the diagnostic ratios and factor analysis, vehicular emission, coal combustion, industry emission, and unburned fossil fuels were suggested to be the PAHs sources at Mount Heng site. However, the reactivity and degradation of individual PAHs could influence the results of PAH source profiles, which deserves further investigations in the future.

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

    Science.gov (United States)

    Karaca, Gizem; Tasdemir, Yucel

    2013-01-01

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

  13. Effect of pyrolysis temperatures on freely dissolved polycyclic aromatic hydrocarbon (PAH) concentrations in sewage sludge-derived biochars.

    Science.gov (United States)

    Zielińska, Anna; Oleszczuk, Patryk

    2016-06-01

    The aim of this study was to evaluate the effect of sewage sludge pyrolysis on freely dissolved (Cfree) polycyclic aromatic hydrocarbon (PAH) contents in biochars. Four sewage sludges with varying properties and PAH contents were pyrolysed at temperatures of 500 °C, 600 °C or 700 °C. Cfree PAH contents were determined using polyoxymethylene (POM). The contents of Cfree PAHs in the sludges ranged from 262 to 294 ng L(-1). Sewage sludge-derived biochars have from 2.3- to 3.4-times lower Cfree PAH contents comparing to corresponding sewage sludges. The Cfree PAH contents in the biochars ranged between 81 ng L(-1) and 126 ng L(-1). As regards agricultural use of biochar, the lower contents of Cfree PAHs in the biochars compared to the sewage sludges makes biochar a safer material than sewage sludge in terms of PAH contents. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Bioremediation mechanisms of combined pollution of PAHs and heavy metals by bacteria and fungi: A mini review.

    Science.gov (United States)

    Liu, Shao-Heng; Zeng, Guang-Ming; Niu, Qiu-Ya; Liu, Yang; Zhou, Lu; Jiang, Lu-Hua; Tan, Xiao-Fei; Xu, Piao; Zhang, Chen; Cheng, Min

    2017-01-01

    In recent years, knowledge in regard to bioremediation of combined pollution of polycyclic aromatic hydrocarbons (PAHs) and heavy metals by bacteria and fungi has been widely developed. This paper reviews the species of bacteria and fungi which can tackle with various types of PAHs and heavy metals entering into environment simultaneously or successively. Microbial activity, pollutants bioavailability and environmental factors (e.g. pH, temperature, low molecular weight organic acids and humic acids) can all affect the bioremediation of PAHs and heavy metals. Moreover, this paper summarizes the remediation mechanisms of PAHs and heavy metals by microbes via elucidating the interaction mechanisms of heavy metals with heavy metals, PAHs/PAHs metabolites with PAHs and PAHs with heavy metals. Based on the above reviews, this paper also discusses the potential research needs for this field. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. PAH volatilization following application of coal-tar-based pavement sealant

    Science.gov (United States)

    Van Metre, Peter C.; Majewski, Michael S.; Mahler, Barbara J.; Foreman, William T.; Braun, Christopher L.; Wilson, Jennifer T.; Burbank, Teresa L.

    2012-01-01

    Coal-tar-based pavement sealants, a major source of PAHs to urban water bodies, have recently been identified as a source of volatile PAHs to the atmosphere. We tracked the volatilization of PAHs for 1 year after application of a coal-tar-based pavement sealant by measuring gas-phase PAH concentrations above the pavement surface and solid-phase PAH concentrations in sealant scraped from the surface. Gas-phase concentrations at two heights (0.03 and 1.28 m) and wind speed were used to estimate volatilization flux. The sum of the concentrations of eight frequently detected PAHsPAH8) in the 0.03-m sample 1.6 h after application (297,000 ng m-3) was about 5000 times greater than that previously reported for the same height above unsealed parking lots (66 ng m-3). Flux at 1.6 h after application was estimated at 45,000 μg m-2 h-1 and decreased rapidly during the 45 days after application to 160 μg m-2 h-1. Loss of PAHs from the adhered sealant also was rapid, with about a 50% decrease in solid-phase ΣPAH8 concentration over the 45 days after application. There was general agreement, given the uncertainties, in the estimated mass of ΣPAH8 lost to the atmosphere on the basis of air sampling (2–3 g m-2) and adhered sealant sampling (6 g m-2) during the first 16 days after application, translating to a loss to the atmosphere of one-quarter to one-half of the PAHs in the sealcoat product. Combining the estimated mass of ΣPAH8 released to the atmosphere with a national-use estimate of coal-tar-based sealant suggests that PAH emissions from new coal-tar-based sealcoat applications each year (~1000 Mg) are larger than annual vehicle emissions of PAHs for the United States.

  16. Current state of knowledge in microbial degradation of polycyclic aromatic hydrocarbons (PAHs: a review

    Directory of Open Access Journals (Sweden)

    Debajyoti Ghosal

    2016-08-01

    Full Text Available Polycyclic aromatic hydrocarbons (PAHs include a group of organic priority pollutants of critical environmental and public health concern due to their toxic, genotoxic, mutagenic and/or carcinogenic properties and their ubiquitous occurrence as well as recalcitrance. The increased awareness of their various adverse effects on ecosystem and human health has led to a dramatic increase in research aimed towards removing PAHs from the environment. PAHs may undergo adsorption, volatilization, photolysis, and chemical oxidation, although transformation by microorganisms is the major neutralization process of PAH-contaminated sites in an ecologically accepted manner. Microbial degradation of PAHs depends on various environmental conditions, such as nutrients, number and kind of the microorganisms, nature as well as chemical property of the PAH being degraded. A wide variety of bacterial, fungal and algal species have the potential to degrade/transform PAHs, among which bacteria and fungi mediated degradation has been studied most extensively. In last few decades microbial community analysis, biochemical pathway for PAHs degradation, gene organization, enzyme system, genetic regulation for PAH degradation have been explored in great detail. Although, xenobiotic-degrading microorganisms have incredible potential to restore contaminated environments inexpensively yet effectively, but new advancements are required to make such microbes effective and more powerful in removing those compounds, which were once thought to be recalcitrant. Recent analytical chemistry and genetic engineering tools might help to improve the efficiency of degradation of PAHs by microorganisms, and minimize uncertainties of successful bioremediation. However, appropriate implementation of the potential of naturally occurring microorganisms for field bioremediation could be considerably enhanced by optimizing certain factors such as bioavailability, adsorption and mass transfer of

  17. Impact of electrochemical treatment of soil washing solution on PAH degradation efficiency and soil respirometry

    International Nuclear Information System (INIS)

    Mousset, Emmanuel; Huguenot, David; Hullebusch, Eric D. van; Oturan, Nihal; Guibaud, Gilles; Esposito, Giovanni; Oturan, Mehmet A.

    2016-01-01

    The remediation of a genuinely PAH-contaminated soil was performed, for the first time, through a new and complete investigation, including PAH extraction followed by advanced oxidation treatment of the washing solution and its recirculation, and an analysis of the impact of the PAH extraction on soil respirometry. The study has been performed on the remediation of genuine PAH-contaminated soil, in the following three steps: (i) PAH extraction with soil washing (SW) techniques, (ii) PAH degradation with an electro-Fenton (EF) process, and (iii) recirculation of the partially oxidized effluent for another SW cycle. The following criteria were monitored during the successive washing cycles: PAH extraction efficiency, PAH oxidation rates and yields, extracting agent recovery, soil microbial activity, and pH of soil. Two representative extracting agents were compared: hydroxypropyl-beta-cyclodextrin (HPCD) and a non-ionic surfactant, Tween"® 80. Six PAH with different numbers of rings were monitored: acenaphthene (ACE), phenanthrene (PHE), fluoranthene (FLA), pyrene (PYR), benzo(a)pyrene (BaP), and benzo(g,h,i)perylene (BghiP). Tween"® 80 showed much better PAH extraction efficiency (after several SW cycles) than HPCD, regardless of the number of washing cycles. Based on successive SW experiments, a new mathematical relation taking into account the soil/water partition coefficient (Kd*) was established, and could predict the amount of each PAH extracted by the surfactant with a good correlation with experimental results (R"2 > 0.975). More HPCD was recovered (89%) than Tween"® 80 (79%), while the monitored pollutants were completely degraded (>99%) after 4 h and 8 h, respectively. Even after being washed with partially oxidized solutions, the Tween"® 80 solutions extracted significantly more PAH than HPCD and promoted better soil microbial activity, with higher oxygen consumption rates. Moreover, neither the oxidation by-products nor the acidic media (p

  18. Current State of Knowledge in Microbial Degradation of Polycyclic Aromatic Hydrocarbons (PAHs): A Review

    Science.gov (United States)

    Ghosal, Debajyoti; Ghosh, Shreya; Dutta, Tapan K.; Ahn, Youngho

    2016-01-01

    Polycyclic aromatic hydrocarbons (PAHs) include a group of organic priority pollutants of critical environmental and public health concern due to their toxic, genotoxic, mutagenic and/or carcinogenic properties and their ubiquitous occurrence as well as recalcitrance. The increased awareness of their various adverse effects on ecosystem and human health has led to a dramatic increase in research aimed toward removing PAHs from the environment. PAHs may undergo adsorption, volatilization, photolysis, and chemical oxidation, although transformation by microorganisms is the major neutralization process of PAH-contaminated sites in an ecologically accepted manner. Microbial degradation of PAHs depends on various environmental conditions, such as nutrients, number and kind of the microorganisms, nature as well as chemical property of the PAH being degraded. A wide variety of bacterial, fungal and algal species have the potential to degrade/transform PAHs, among which bacteria and fungi mediated degradation has been studied most extensively. In last few decades microbial community analysis, biochemical pathway for PAHs degradation, gene organization, enzyme system, genetic regulation for PAH degradation have been explored in great detail. Although, xenobiotic-degrading microorganisms have incredible potential to restore contaminated environments inexpensively yet effectively, but new advancements are required to make such microbes effective and more powerful in removing those compounds, which were once thought to be recalcitrant. Recent analytical chemistry and genetic engineering tools might help to improve the efficiency of degradation of PAHs by microorganisms, and minimize uncertainties of successful bioremediation. However, appropriate implementation of the potential of naturally occurring microorganisms for field bioremediation could be considerably enhanced by optimizing certain factors such as bioavailability, adsorption and mass transfer of PAHs. The main

  19. Source apportionment of atmospheric polycyclic aromatic hydrocarbons (PAHs) in Palm Beach County, Florida.

    Science.gov (United States)

    Afshar-Mohajer, Nima; Wilson, Christina; Wu, Chang-Yu; Stormer, James E

    2016-04-01

    Due to concerns about adverse health effects associated with inhalation of atmospheric polycyclic aromatic hydrocarbons (PAHs), 30 ambient air samples were obtained at an air quality monitoring station in Palm Beach County, Florida, from March 2013 to March 2014. The ambient PAH concentration measurements and fractional emission rates of known sources were incorporated into a chemical mass balance model, CMB8.2, developed by EPA, to apportion contributions of three major PAH sources including preharvest sugarcane burning, mobile vehicles, and wildland fires. Strong association between the number of benzene rings and source contribution was found, and mobile vehicles were identified to be the prevailing source (contribution≥56%) for the observed PAHs concentration with lower molecular weights (four or fewer benzene rings) throughout the year. Preharvest sugarcane burning was the primary contributing source for PAHs with relatively higher molecular weights (five or more benzene rings) during the sugarcane burning season (from October to May of the next year). Source contribution of wildland fires varied among PAH compounds but was consistently lower than for sugarcane burning during the sugarcane harvest season. Determining the major sources responsible for ground-level PAHs serves as a tool to improving management strategies for PAH emitting sources and a step toward better protection of the health of residents in terms of exposure to PAHs. The results obtain insight into temporal dominance of PAH polluting sources for those residential areas located near sugarcane burning facilities and have implications beyond Palm Beach County, in areas with high concerns of PAHs and their linked sources. Source apportionment of atmospheric polycyclic hydrocarbons (PAHs) in Palm Beach County, Florida, meant to estimate contributions of major sources in PAH concentrations measured at Belle Glade City of Palm Beach County. Number of benzene rings was found to be the key parameter

  20. Excess cash holdings and shareholder value

    OpenAIRE

    Lee, Edward; Powell, Ronan

    2011-01-01

    We examine the determinants of corporate cash holdings in Australia and the impact on shareholder wealth of holding excess cash. Our results show that a trade-off model best explains the level of a firm’s cash holdings in Australia. We find that 'transitory' excess cash firms earn significantly higher risk-adjusted returns compared to 'persistent' excess cash firms, suggesting that the market penalises firms that hoard cash. The marginal value of cash also declines with larger cash balances, ...

  1. APPLICATION OF FENTON’S REAGENT ON REMEDIATION OF POLYCYCLIC AROMATIC HYDROCARBONs (PAHs IN SPIKED SOIL

    Directory of Open Access Journals (Sweden)

    Nursiah La Nafie

    2010-06-01

    Full Text Available Problem associated with Polycyclic Aromatic Hydrocarbons (PAHs contaminated site in environmental media have received increasing attention. To resolve such problems, innovative in situ methods are urgently required. This work investigated the feasibility of using Fenton's Reagent to remediate PAHs in spiked soil. PAHs were spiked into soil to simulate contaminated soil. Fenton's Reagent (H2O2 + Fe2+ and surfactant were very efficient in destruction of PAHs including naphthalene, anthracene, fluoranthene, pyrene, and benzo(apyrene from spiked soil. It was indicated by the fact that more than 96% of PAHs were degraded in the solution and the spiked soil.   Keywords: Environmental, Fenton's Reagent, Polycyclic Aromatic Hydrocarbons, and Spiked soil.

  2. Assessing PAH removal from clayey soil by means of electro-osmosis and electrodialysis

    DEFF Research Database (Denmark)

    Lima, Ana T.; Ottosen, Lisbeth M.; Heister, Katja

    2012-01-01

    Polycyclic aromatic hydrocarbons (PAH) are persistent and toxic contaminants which are difficult to remove from fine porous material like clayey soils. The present work aims at studying two electroremediation techniques for the removal of PAHs from a spiked natural silt soil from Saudi Arabia...... and a silty loam soil from The Netherlands which has been exposed to tar contamination for over 100years. The two techniques at focus are electro-osmosis and electrodialysis. The latter is applied for the first time for the removal of PAH. The efficiency of the techniques is studied using these two soils......, having been subjected to different PAH contact times.Two surfactants were used: the non-ionic surfactant Tween 80 and anionic surfactant sodium dodecyl sulphate (SDS) to aid desorption of PAHs from the soil. Results show a large discrepancy in the removal rates between spiked soil and long-term field...

  3. PAH Metabolites in Bile of European Eel (Anguilla anguilla) from Morocco.

    Science.gov (United States)

    Wariaghli, Fatima; Kammann, Ulrike; Hanel, Reinhold; Yahyaoui, Ahmed

    2015-12-01

    Environmental pollution of fish with organic contaminants is a topic of rising attention in Morocco. Polycyclic aromatic hydrocarbons (PAH) are prominent organic contaminants which are rapidly metabolized in fish. Their metabolites are accumulated in the bile fluid and can be used to assess PAH exposure. The two PAH metabolites 1-hydroxypyrene and 1-hydroxyphenanthrene were quantified in European eels (Anguilla anguilla) from two Moroccan river systems by high-performance liquid chromatography with fluorescence detection. Mean values ranged from 52 to 210 ng/mL 1-hydroxypyrene and from 61 to 73 ng/mL 1-hydroxyphenanthrene. The overall concentrations of PAH metabolites in eel from Morocco appeared moderate compared to eel from European rivers and coastal sites. The present study provides first information on concentrations of PAH metabolites in fish from Morocco.

  4. Review of the quantification techniques for polycyclic aromatic hydrocarbons (PAHs) in food products.

    Science.gov (United States)

    Bansal, Vasudha; Kumar, Pawan; Kwon, Eilhann E; Kim, Ki-Hyun

    2017-10-13

    There is a growing need for accurate detection of trace-level PAHs in food products due to the numerous detrimental effects caused by their contamination (e.g., toxicity, carcinogenicity, and teratogenicity). This review aims to discuss the up-to-date knowledge on the measurement techniques available for PAHs contained in food or its related products. This article aims to provide a comprehensive outline on the measurement techniques of PAHs in food to help reduce their deleterious impacts on human health based on the accurate quantification. The main part of this review is dedicated to the opportunities and practical options for the treatment of various food samples and for accurate quantification of PAHs contained in those samples. Basic information regarding all available analytical measurement techniques for PAHs in food samples is also evaluated with respect to their performance in terms of quality assurance.

  5. The infrared emission bands. III. Southern IRAS sources.

    Science.gov (United States)

    Cohen, M; Tielens, A G; Bregman, J; Witteborn, F C; Rank, D M; Allamandola, L J; Wooden, D H; de Muizon, M

    1989-06-01

    We present airborne 5-8 micrometers spectra of southern IRAS sources which reveal strong polycyclic aromatic hydrocarbon (PAH) emission features. The good correlation between the bands, in particular the dominant 6.2 and "7.7" micrometers features, strongly imply a common carrier, reinforcing the PAH hypothesis. However, small but detectable spectral variations exist. Planetaries have a distinctly different ratio of I(6.2)/I(7.7) than other nebulae, accompanied by a redward shift in the actual wavelength of the "7.7" micrometers peak. Further, we have detected a new feature, previously predicted from laboratory spectra of PAH molecules, at 5.2 micrometers in many of these sources. Spectra of two rare [WC 10] planetary nebular nuclei indicate a very prominent plateau of emission, linking the 6.2 and 7.7 micrometers bands. Several of our sources show definite evidence for emission structure between 14 and 23 micrometers in their IRAS Low-Resolution Spectral Atlas spectra: we attribute this structure to PAH bands. too. We have defined the "generic" spectrum of emission bands relating the mean intensities of each band to that of the strongest, near 7.7 micrometers. We have added three more planetary or protoplanetary nebulae to our correlation between 7.7 micrometers band intensity and nebular gas phase C/O ratio, namely NGC 6302, HR 4049, and the highly carbon-rich [WC 10] nucleus, CPD--56 degrees 8032. For the latter we have determined a ratio for C/O of approximately 4.8 from IUE observations. The good correlation between the intensity ratio of the "7.7" micrometers feature relative to the far-infrared dust continuum and nebular C/O also supports a carbonaceous carrier for these emission features.

  6. Syndromes associated with nutritional deficiency and excess.

    Science.gov (United States)

    Jen, Melinda; Yan, Albert C

    2010-01-01

    Normal functioning of the human body requires a balance between nutritional intake and metabolism, and imbalances manifest as nutritional deficiencies or excess. Nutritional deficiency states are associated with social factors (war, poverty, famine, and food fads), medical illnesses with malabsorption (such as Crohn disease, cystic fibrosis, and after bariatric surgery), psychiatric illnesses (eating disorders, autism, alcoholism), and medications. Nutritional excess states result from inadvertent or intentional excessive intake. Cutaneous manifestations of nutritional imbalance can herald other systemic manifestations. This contribution discusses nutritional deficiency and excess syndromes with cutaneous manifestations of particular interest to clinical dermatologists. Copyright © 2010. Published by Elsevier Inc.

  7. Evidences for balancing selection from PAH-BglII and PAH-EcoRI polymorphisms in Isfahan population

    Directory of Open Access Journals (Sweden)

    Zahra Fazeli Attar

    2010-01-01

    Full Text Available Two polymorphic markers including BglII and EcoRI, were identified at intron 1 and intron 5 of PAH gene. In order to test whether these polymorphisms are behaving as neutral alleles or are being subjected to selective pressures in Isfahan population, 110 individuals were genotyped by PCR-RFLP. The Arlequin input file was prepared by use of phase-known haplotype data and Neutrality tests (Tajima D test and Fu’s Fs test were done using Arlequin program. 42 individuals were found heterozygous for both polymorphisms whose haplotype phase remained unknown. The BglII-EcoRI haplotype phase was known only at 68 individuals who were used for preparation of input file. Tajima's D value and Fs value at Isfahan population were 1.7 and 1.02, respectively. Positive values of Fs and D>0 indicated that these polymorphisms are under selection pressure at Isfahan population. Although these polymorphisms were in the non-coding region of PAH gene, but these were not neutral alleles and positive values of these tests provided evidence for balancing selection of these polymorphisms at Isfahan population. The results of this study could improve our understanding of evolutionary history and structure of Isfahan population.

  8. Polycyclic aromatic hydrocarbons (PAHs) biodegradation potential and diversity of microbial consortia enriched from tsunami sediments in Miyagi, Japan

    Energy Technology Data Exchange (ETDEWEB)

    Bacosa, Hernando Pactao, E-mail: hernando.bacosa@utexas.edu [Graduate School of Environmental Studies, Tohoku University, Aoba 6-6-20, Aramaki, Aoba-ku, Sendai 980-8579 (Japan); Marine Science Institute, The University of Texas at Austin, 750 Channel View Drive, Port Aransas, TX 78373 (United States); Inoue, Chihiro [Graduate School of Environmental Studies, Tohoku University, Aoba 6-6-20, Aramaki, Aoba-ku, Sendai 980-8579 (Japan)

    2015-02-11

    Highlights: • Most bacterial consortia from tsunami sediment degraded PAH mixture and pyrene. • The consortia were dominated by known and unknown PAHs-degrading bacteria. • Dokdonella clone is a potential new species and PAH degrader from tsunami sediment. • PAH-RHDα is better than nidA gene for estimating pyrene-degraders in the consortia. • First report on the PAH degradation and PAH-degrading bacteria from tsunami sediment. - Abstract: The Great East Japan Earthquake caused tsunamis and resulted in widespread damage to human life and infrastructure. The disaster also resulted in contamination of the environment by chemicals such as polycyclic aromatic hydrocarbons (PAHs). This study was conducted to investigate the degradation potential and describe the PAH-degrading microbial communities from tsunami sediments in Miyagi, Japan. PAH-degrading bacteria were cultured by enrichment using PAH mixture or pyrene alone as carbon and energy sources. Among the ten consortia tested for PAH mixture, seven completely degraded fluorene and more than 95% of phenanthrene in 10 days, while only four consortia partially degraded pyrene. Six consortia partially degraded pyrene as a single substrate. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) revealed that each sample was dominated by unique microbial populations, regardless of sampling location. The consortia were dominated by known PAHs degraders including Sphingomonas, Pseudomonas, and Sphingobium; and previously unknown degraders such as Dokdonella and Luteimonas. A potentially novel and PAH-degrading Dokdonella was detected for the first time. PAH-ring hydroxylating dioxygenase (PAH-RHDα) gene was shown to be more effective than nidA in estimating pyrene-degrading bacteria in the enriched consortia. The consortia obtained in this study are potential candidates for remediation of PAHs contaminated soils.

  9. Monitoring of polycyclic aromatic hydrocarbons (PAH) in food supplements containing botanicals and other ingredients on the Dutch market.

    Science.gov (United States)

    Martena, M J; Grutters, M M P; De Groot, H N; Konings, E J M; Rietjens, I M C M

    2011-01-01

    Food supplements can contain polycyclic aromatic hydrocarbons (PAH). The European Food Safety Authority (EFSA) has defined 16 priority PAH that are both genotoxic and carcinogenic and identified eight priority PAH (PAH8) or four of these (PAH4) as good indicators of the toxicity and occurrence of PAH in food. The current study aimed to determine benzo[a]pyrene and other EFSA priority PAH in different categories of food supplements containing botanicals and other ingredients. From 2003 to 2008, benzo[a]pyrene exceeded the limit of quantification (LOQ) in 553 (44%) of 1258 supplements with a lower-bound mean of 3.37 µg kg(-1). In 2008 and 2009, benzo[a]pyrene and 12 other EFSA priority PAH were determined in 333 food supplements. Benzo[a]pyrene exceeded the LOQ in 210 (63%) food supplements with a lower-bound mean of 5.26 µg kg(-1). Lower-bound mean levels for PAH4 and PAH8(-indeno[1,2,3-cd]pyrene) were 33.5 and 40.5 µg kg(-1), respectively. Supplements containing resveratrol, Ginkgo biloba, St. John's wort and propolis showed relatively high PAH4 levels in 2008 and 2009. Before 2008, supplements with these ingredients and also dong quai, green tea or valerian contained relatively high benzo[a]pyrene levels. On average, PAH4 intake resulting from food supplement use will be at the lower end of the range of contributions of main food groups to PAH4 exposure, although individual food supplements can contribute significantly to PAH4 exposure. Regular control of EFSA indicator PAH levels in food supplements may prove a way forward to reduce further the intake of PAH from food.

  10. Effect of single and mixed polycyclic aromatic hydrocarbon contamination on plant biomass yield and PAH dissipation during phytoremediation.

    Science.gov (United States)

    Afegbua, Seniyat Larai; Batty, Lesley Claire

    2018-04-27

    Polycyclic aromatic hydrocarbon (PAH)-contaminated sites have a mixture of PAH of varying concentration which may affect PAH dissipation differently to contamination with a single PAH. In this study, pot experiments investigated the impact of PAH contamination on Medicago sativa, Lolium perenne, and Festuca arundinacea biomass and PAH dissipation from soils spiked with phenanthrene (Phe), fluoranthene (Flu), and benzo[a]pyrene (B[a]P) in single and mixed treatments. Stimulatory or inhibitory effects of PAH contamination on plant biomass yields were not different for the single and mixed PAH treatments. Results showed significant effect of PAH treatments on plant growth with an increased root biomass yield for F. arundinacea in the Phe (175%) and Flu (86%) treatments and a root biomass decrease in the mixed treatment (4%). The mean residual PAHs in the planted treatments and unplanted control for the single treatments were not significantly different. B[a]P dissipation was enhanced for single and mixed treatments (71-72%) with F. arundinacea compared to the unplanted control (24-50%). On the other hand, B[a]P dissipation was inhibited with L. perenne (6%) in the single treatment and M. sativa (11%) and L. perenne (29%) in the mixed treatment. Abiotic processes had greater contribution to PAH dissipation compared to rhizodegradation in both treatments. In most cases, a stimulatory effect of PAH contamination on plant biomass yield without an enhancement of PAH dissipation was observed. Plant species among other factors affect the relative contribution of PAH dissipation mechanisms during phytoremediation. These factors determine the effectiveness and suitability of phytoremediation as a remedial strategy for PAH-contaminated sites. Further studies on impact of PAH contamination, plant selection, and rhizosphere activities on soil microbial community structure and remediation outcome are required.

  11. Polycyclic aromatic hydrocarbons (PAHs) biodegradation potential and diversity of microbial consortia enriched from tsunami sediments in Miyagi, Japan

    International Nuclear Information System (INIS)

    Bacosa, Hernando Pactao; Inoue, Chihiro

    2015-01-01

    Highlights: • Most bacterial consortia from tsunami sediment degraded PAH mixture and pyrene. • The consortia were dominated by known and unknown PAHs-degrading bacteria. • Dokdonella clone is a potential new species and PAH degrader from tsunami sediment. • PAH-RHDα is better than nidA gene for estimating pyrene-degraders in the consortia. • First report on the PAH degradation and PAH-degrading bacteria from tsunami sediment. - Abstract: The Great East Japan Earthquake caused tsunamis and resulted in widespread damage to human life and infrastructure. The disaster also resulted in contamination of the environment by chemicals such as polycyclic aromatic hydrocarbons (PAHs). This study was conducted to investigate the degradation potential and describe the PAH-degrading microbial communities from tsunami sediments in Miyagi, Japan. PAH-degrading bacteria were cultured by enrichment using PAH mixture or pyrene alone as carbon and energy sources. Among the ten consortia tested for PAH mixture, seven completely degraded fluorene and more than 95% of phenanthrene in 10 days, while only four consortia partially degraded pyrene. Six consortia partially degraded pyrene as a single substrate. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) revealed that each sample was dominated by unique microbial populations, regardless of sampling location. The consortia were dominated by known PAHs degraders including Sphingomonas, Pseudomonas, and Sphingobium; and previously unknown degraders such as Dokdonella and Luteimonas. A potentially novel and PAH-degrading Dokdonella was detected for the first time. PAH-ring hydroxylating dioxygenase (PAH-RHDα) gene was shown to be more effective than nidA in estimating pyrene-degrading bacteria in the enriched consortia. The consortia obtained in this study are potential candidates for remediation of PAHs contaminated soils

  12. Vertical distributions of PAHs in the sediments of four lakes in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Fukushima, Takehiko; Watanabe, Seigo; Kamiya, Koichi [Tsukuba Univ., Ibaraki (Japan). Graduate School of Life and Environment; Ozaki, Noriatsu [Hiroshima Univ., Higashihiroshima (Japan). Graduate School of Engineering

    2012-12-15

    Purpose: The purpose of this study was to elucidate historical trends, spatial variations, and the sources of polycyclic aromatic hydrocarbons (PAHs) pollution in several Japanese lakes. Materials and methods: The vertical distributions of PAHs in the core samples of sediments taken at several points in lakes Kasumigaura, Suwa, Kizaki, and Shinji were determined using a gas chromatograph equipped with a mass selective detector and combined with chronological information and the physical/elemental properties of the sediment. Results and discussion: Seventeen related compounds (congeners) typically had concentration peaks at sediment depths corresponding to the 1960s to 1970s. In Lake Shinji and one bay of Lake Kasumigaura, there was a tendency for PAH concentrations to increase downstream; in contrast, another bay of Lake Kasumigaura showed the reverse trend. During big flood events, the fluxes of PAHs increased due to large inputs of particulate matter, although PAH concentrations were reduced. For the four study lakes and other similar lakes, PAH concentrations of surface sediments were approximately proportional to population densities in the respective watersheds, while the total input of PAHs to the lakes were correlated with their population and watershed area. The source apportionment analysis using isomer ratios for the congener profiles indicated that the principal sources of the PAHs in the lake sediments were gasoline and/or diesel engine exhausts and biomass burning. Conclusions: The observed concentration peaks showed a deterioration of the chemical quality of atmospheric conditions around 1960-1970 and a recent tendency for their amelioration. Between-lake differences suggest that the influence of human activity in the watersheds influences sediment PAH concentrations. The PAH sources were identified to be of pyrogenic origin. (orig.)

  13. Rapid collection, detection, and assessment of environmental polycyclic aromatic hydrocarbons (PAHs)

    International Nuclear Information System (INIS)

    Johnson, T.; Huckins, J.; Petty, J.; Butorin, A.

    1995-01-01

    PAHs, an important class of environmental chemical contaminants found primarily in petroleum and coal products, frequently are the most numerous and ubiquitous organic pollutants recovered in sediment residues. PAHs are considered hazardous in water and soil because many are acutely toxic and have the potential for genotoxic activity. Selected EPA priority pollutants (2, 3, 4, and 5-ring PAHs) and complex PAH mixtures (crude oil, gasoline, and recycled motor oil) were collected and concentrated from water and sediment with semipermeable polymeric membrane devices (SPMDs) that contain a thin film of triolein. Analytes were extracted from the SPMDs by dialysis in hexane or directly by rinsing with acetone DMSO, concentrated in the carrier solvent DMSO, and detected with the luminescent bacterial assays Microtox reg-sign and Mutatox reg-sign. High SPMD-water concentration factors of PAHs appeared to correspond closely to the occurrence of PAHs in sediments previously reported in the literature; for example, pyrene had the highest SPMD concentration factor and was the most commonly found PAH in sediment residues. Mutatox reg-sign with rat hepatic S9 activation detected all PAHs tested. The PAH's molecular weight and number of rings appeared to directly influence acute toxicity (EC50, microg/mL); for example, two-ring naphthalene had an EC50 value of 0.78 whereas five-ring benzo(a)pyrene had an EC50 value of 15.0, about a twenty-fold difference, Microtox reg-sign and Mutatox reg-sign, in combination with SPMDs were able to rapidly (< 24h) assess the bioavailability, toxicity, and genotoxicity of these environmental PAHs

  14. PAH emissions from old and new types of domestic hot water boilers.

    Science.gov (United States)

    Horak, Jiri; Kubonova, Lenka; Krpec, Kamil; Hopan, Frantisek; Kubesa, Petr; Motyka, Oldrich; Laciok, Vendula; Dej, Milan; Ochodek, Tadeas; Placha, Daniela

    2017-06-01

    Five different domestic heating boilers (automatic, over-fire, with down-draft combustion and gasification) and three types of fuel (lignite, wood and mixed fuel) were examined in 25 combustion tests and correlated with the emissions of particulate matter (PM), carbon monoxide (CO), total organic carbon (TOC) and 12 polycyclic aromatic hydrocarbons (PAHs with MW = 178-278 g/mol) focusing on particle phase. However, the distribution of 12 PAHs in gas phase was considered as well due to the presence mainly of lighter PAHs in gas phase. The PAHs, as well as the CO and TOC, are the indicators of incomplete combustion, and in this study PAH emission increased significantly with increasing emissions of CO and TOC. The PAHs were mainly detected on PM 2.5 , their contents were increasing linearly with increasing PM 2.5 emissions. The highest emission factors of PAHs were measured for boilers of old construction, such as over-fire boiler (5.8-929 mg/kg) and boiler with down-draft combustion (3.1-54.1 mg/kg). Modern types of boilers produced much lower emissions of PAHs, in particular, automatic boiler (0.3-3.3 mg/kg) and gasification boilers (0.2-6.7 mg/kg). In general, the inefficient combustion at reduced output of boilers generated 1.4-17.7 times more emissions of PAHs than the combustion at nominal output of boilers. It is recommended to operate boilers at nominal output with sufficient air supply and to use the proper fuel to minimise PAHs emissions from domestic heating appliances. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. MAGNETIC GRAIN TRAPPING AND THE HOT EXCESSES AROUND EARLY-TYPE STARS

    Energy Technology Data Exchange (ETDEWEB)

    Rieke, G. H.; Gáspár, András; Ballering, N. P., E-mail: grieke@as.arizona.edu, E-mail: agaspar@as.arizona.edu, E-mail: ballerin@email.arizona.edu [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States)

    2016-01-10

    A significant fraction of main sequence stars observed interferometrically in the near-infrared have slightly extended components that have been attributed to very hot dust. To match the spectrum appears to require the presence of large numbers of very small (<200 nm in radius) dust grains. However, particularly for the hotter stars, it has been unclear how such grains can be retained close to the star against radiation pressure force. We find that the expected weak stellar magnetic fields are sufficient to trap nm-sized dust grains in epicyclic orbits for a few weeks or longer, sufficient to account for the hot excess emission. Our models provide a natural explanation for the requirement that the hot excess dust grains be smaller than 200 nm. They also suggest that magnetic trapping is more effective for rapidly rotating stars, consistent with the average vsini measurements of stars with hot excesses being larger (at ∼2σ) than those for stars without such excesses.

  16. CHARACTERIZING THE INFRARED SPECTRA OF SMALL, NEUTRAL, FULLY DEHYDROGENATED POLYCYCLIC AROMATIC HYDROCARBONS

    Energy Technology Data Exchange (ETDEWEB)

    Mackie, C. J.; Peeters, E.; Cami, J. [Department of Physics and Astronomy, University of Western Ontario, London, ON N6A 3K7 (Canada); Bauschlicher, C. W. Jr., E-mail: mackie@strw.leidenuniv.nl [NASA Ames Research Center, MS 245-6, Moffett Field, CA 94035 (United States)

    2015-02-01

    We present the results of a computational study to investigate the infrared spectroscopic properties of a large number of polycyclic aromatic hydrocarbon (PAH) molecules and their fully dehydrogenated counterparts. We constructed a database of fully optimized geometries for PAHs that is complete for eight or fewer fused benzene rings, thus containing 1550 PAHs and 805 fully dehydrogenated aromatics. A large fraction of the species in our database have clearly non-planar or curved geometries. For each species, we determined the frequencies and intensities of their normal modes using density functional theory calculations. Whereas most PAH spectra are fairly similar, the spectra of fully dehydrogenated aromatics are much more diverse. Nevertheless, these fully dehydrogenated species show characteristic emission features at 5.2 μm, 5.5 μm, and 10.6 μm; at longer wavelengths, there is a forest of emission features in the 16-30 μm range that appears as a structured continuum, but with a clear peak centered around 19 μm. We searched for these features in Spitzer-IRS spectra of various positions in the reflection nebula NGC 7023. We find a weak emission feature at 10.68 μm in all positions except that closest to the central star. We also find evidence for a weak 19 μm feature at all positions that is not likely due to C{sub 60}. We interpret these features as tentative evidence for the presence of a small population of fully dehydrogenated PAHs, and discuss our results in the framework of PAH photolysis and the formation of fullerenes.

  17. Developmental toxicity of PAH mixtures in fish early life stages. Part II: adverse effects in Japanese medaka.

    Science.gov (United States)

    Le Bihanic, Florane; Clérandeau, Christelle; Le Menach, Karyn; Morin, Bénédicte; Budzinski, Hélène; Cousin, Xavier; Cachot, Jérôme

    2014-12-01

    In aquatic environments, polycyclic aromatic hydrocarbons (PAHs) mostly occur as complex mixtures, for which risk assessment remains problematic. To better understand the effects of PAH mixture toxicity on fish early life stages, this study compared the developmental toxicity of three PAH complex mixtures. These mixtures were extracted from a PAH-contaminated sediment (Seine estuary, France) and two oils (Arabian Light and Erika). For each fraction, artificial sediment was spiked at three different environmental concentrations roughly equivalent to 0.5, 4, and 10 μg total PAH g(-1) dw. Japanese medaka embryos were incubated on these PAH-spiked sediments throughout their development, right up until hatching. Several endpoints were recorded at different developmental stages, including acute endpoints, morphological abnormalities, larvae locomotion, and genotoxicity (comet and micronucleus assays). The three PAH fractions delayed hatching, induced developmental abnormalities, disrupted larvae swimming activity, and damaged DNA at environmental concentrations. Differences in toxicity levels, likely related to differences in PAH proportions, were highlighted between fractions. The Arabian Light and Erika petrogenic fractions, containing a high proportion of alkylated PAHs and low molecular weight PAHs, were more toxic to Japanese medaka early life stages than the pyrolytic fraction. This was not supported by the toxic equivalency approach, which appeared unsuitable for assessing the toxicity of the three PAH fractions to fish early life stages. This study highlights the potential risks posed by environmental mixtures of alkylated and low molecular weight PAHs to early stages of fish development.

  18. C2D spitzer-IRS spectra of disks around T tauri stars : II. PAH emission features

    NARCIS (Netherlands)

    Geers, V. C.; Augereau, J. -C; Pontoppidan, K. M.; Dullemond, C. P.; Visser, R.; Kessler-Silacci, J. E.; Evans, N. J.; van Dishoeck, E. F.; Blake, G. A.; Boogert, A. C. A.; Lahuis, F.; Merin, B.

    Aims. We search for Polycyclic Aromatic Hydrocarbon (PAH) features towards young low-mass (T Tauri) stars and compare them with surveys of intermediate mass (Herbig Ae/Be) stars. The presence and strength of the PAH features are interpreted with disk radiative transfer models exploring the PAH

  19. Deciphering the roles of Arabidopsis LPCAT and PAH in phosphatidylcholine homeostasis and pathway coordination for chloroplast lipid synthesis.

    Science.gov (United States)

    Wang, Liping; Kazachkov, Michael; Shen, Wenyun; Bai, Mei; Wu, Hong; Zou, Jitao

    2014-12-01

    Phosphatidylcholine (PC) is a key intermediate in the metabolic network of glycerolipid biosynthesis. Lysophosphatidylcholine acyltransferase (LPCAT) and phosphatidic acid phosphatase (PAH) are two key enzymes of PC homeostasis. We report that LPCAT activity is markedly induced in the Arabidopsis pah mutant. The quadruple pah lpcat mutant, with dual defects in PAH and LPCAT, had a level of lysophosphatidylcholine (LPC) that was much higher than that in the lpcat mutants and a PC content that was higher than that in the pah mutant. Comparative molecular profile analysis of monogalactosyldiacylglycerol and digalactosyldiacylglycerol revealed that both the pah and pah lpcat mutants had increased proportions of 34:6 from the prokaryotic pathway despite differing levels of LPCAT activity. We show that a decreased representation of the C16:0 C18:2 diacylglycerol moiety in PC was a shared feature of pah and pah lpcat, and that this change in PC metabolic profile correlated with the increased prokaryotic contribution to chloroplast lipid synthesis. We detected increased PC deacylation in the pah lpcat mutant that was attributable at least in part to the induced phospholipases. Increased LPC generation was also evident in the pah mutant, but the phospholipases were not induced, raising the possibility that PC deacylation is mediated by the reverse reaction of LPCAT. We discuss possible roles of LPCAT and PAH in PC turnover that impacts lipid pathway coordination for chloroplast lipid synthesis. © 2014 National Research Council Canada. The Plant Journal © 2014 Society For Experimental Biology and John Wiley & Sons.

  20. A method to simultaneously determining the reduction in PAH dissolved concentrations and bioaccessibility in carbon amended soils

    DEFF Research Database (Denmark)

    Marchal, Geoffrey; Smith, Kilian E. C.; Rein, Arno

    In order to investigate the potential of different soil amendments (activated charcoal (AC), charcoal (biochar), compost) to sorb PAHs and their effect on bioaccessibility and biodegradation of PAHs in soil, a method was developed that can determine simultaneously the changes in PAH dissolved...

  1. Infrared observations of the eclipsing millisecond pulsar 1957 + 20

    International Nuclear Information System (INIS)

    Eales, S.A.; Becklin, E.E.; Zuckerman, B.

    1990-01-01

    We have taken 2.2-μm images, over the entire range of orbital phase, of the eclipsing millisecond pulsar 1957 + 20. We show that the 2.2-μm flux from the pulsar system is variable, and that the infrared light curve is similar to the optical light curve. Four additional images at 1.2 μm show that there is a possible infrared excess from the system. (author)

  2. Accumulation of metabolites during bacterial degradation of PAH-mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Vila, J.; Lopez, Z.; Bauza, J.I. [Universitat de Barcelona (Spain). Department de Microbiologia; Minguillon, C. [Parc Cientific de Barcelona (ES). Institut de Recerca de Barcelona (IRB-PCB); Grifoll, M.

    2003-07-01

    In a previous work we identified a number of metabolites accumulated during growth in pyrene by Mycobacterium sp. AP1, and proposed a metabolic pathway for pyrene utilization. In order to confirm and complete this pathway we have isolated and identified the pyrene-degrading strains Mycobacterium sp. PGP2, CP1 and CP2. During growth on pyrene, strains AP1, PGP2, CP1 and CP2 accumulated 4,5-cis-pyrene-dihydrodiol, 4,5-phenanthrene dicarboxylic acid, 4-phenanthrene carboxylic acid, 3,4-dihydroxy-3-hydrophenanthrene-4-carboxylic acid, phthalic acid, and 6,6'-dihydroxy-2,2'-biphenyl dicarboxylic acid. Strains AP1, PGP2, CP1 and CP2 also grew on fluoranthene accumulating acenaphthenone, naphthalene-1,8-dicarboxylic acid, 9-fluorenone-1-carboxylic acid, Z-9-carboxymethylenefluorene-1-carboxylic acid and benzene-1,2,3-tricarboxylic acid. Similar metabolites were produced during growth onf fluoranthene by the Gram-positive strains CFt2 and CFt6, isolated by their capability of using this PAH as a sole source of carbon and energy. These fluoranthene-degrading strains also accumulated cis-1,9a-dihydroxy-1-hydrofluorene-9-one-8-carboxylic acid. In addition to pyrene and fluoranthene, all pyrene-degrading utilized phenanthrene as a sole source of carbon and energy, while the fluoranthene-degrading strains were unable to utilize pyrene or phenanthrene. Mycobacterium sp. AP1 acted on a wide range of PAHs, accumulating aromatic dicarboxylic acids, hydroxyacids, and ketones resulting from dioxygenation and ortho-cleavage, dioxygenation and meta-cleavage, and monooxygenation reactions. In cultures of strains AP1 and CP1 with a defined PAH-mixture only 20% removal of the parent compounds was observed. Analysis of acidic extracts showed the accumulation of the anticipated aromatic acids, suggesting that accumulation of acidic compounds could prevent further degradation of the mixture. Those results led us to isolation of strains DF11 and OH3, able to grow on the selected

  3. Infrared Observations of FS CMa Stars

    Science.gov (United States)

    Sitko, Michael L.; Russell, R. W.; Lynch, D. K.; Grady, C. A.; Hammel, H. B.; Beerman, L. C.; Day, A. N.; Huelsman, D.; Rudy, R. J.; Brafford, S. M.; Halbedel, E. M.

    2009-01-01

    A subset of non-supergiant B[e] stars has recently been recognized as forming a fairly unique class of objects with very strong emission lines, infrared excesses, and locations not associated with star formation. The exact evolutionary state of these stars, named for the prototype FS CMa, is uncertain, and they have often been classified as isolated Herbig AeBe stars. We present infrared observations of two of these stars, HD 45677 (FS CMa), HD 50138 (MWC 158), and the candidate FS CMa star HD 190073 (V1295 Aql) that span over a decade in time. All three exhibit an emission band at 10 microns due to amorphous silicates, confirming that much (if not all) of the infrared excess is due to dust. HD 50138 is found to exhibit 20% variability between 3-13 microns that resembles that found in pre-main sequence systems (HD 163296 and HD 31648). HD 45677, despite large changes at visual wavelengths, has remained relatively stable in the infrared. To date, no significant changes have been observed in HD 190073. This work is supported in part by NASA Origins of Solar Systems grant NAG5-9475, NASA Astrophysics Data Program contract NNH05CD30C, and the Independent Research and Development program at The Aerospace Corporation.

  4. Feldspar, Infrared Stimulated Luminescence

    DEFF Research Database (Denmark)

    Jain, Mayank

    2014-01-01

    This entry primarily concerns the characteristics and the origins of infrared-stimulated luminescence in feldspars.......This entry primarily concerns the characteristics and the origins of infrared-stimulated luminescence in feldspars....

  5. Bladder calculus presenting as excessive masturbation.

    Science.gov (United States)

    De Alwis, A C D; Senaratne, A M R D; De Silva, S M P D; Rodrigo, V S D

    2006-09-01

    Masturbation in childhood is a normal behaviour which most commonly begins at 2 months of age, and peaks at 4 years and in adolescence. However excessive masturbation causes anxiety in parents. We describe a boy with a bladder calculus presenting as excessive masturbation.

  6. Measuring excess capital capacity in agricultural production

    NARCIS (Netherlands)

    Zhengfei, G.; Kumbhakar, S.C.; Myers, R.J.; Oude Lansink, A.G.J.M.

    2009-01-01

    We introduce the concept "excess capital capacity" and employ a stochastic input requirement frontier to measure excess capital capacity in agricultural production. We also propose a two-step estimation method that allows endogenous regressors in stochastic frontier models. The first step uses

  7. The excessively crying infant : etiology and treatment

    NARCIS (Netherlands)

    Akhnikh, S.; Engelberts, A.C.; Sleuwen, B.E. van; Hoir, M.P. L’; Benninga, M.A.

    2014-01-01

    Excessive crying, often described as infantile colic, is the cause of 10% to 20% of all early pediatrician visits of infants aged 2 weeks to 3 months. Although usually benign and selflimiting, excessive crying is associated with parental exhaustion and stress. However, and underlying organic cause

  8. Part B Excess Cost Quick Reference Document

    Science.gov (United States)

    Ball, Wayne; Beridon, Virginia; Hamre, Kent; Morse, Amanda

    2011-01-01

    This Quick Reference Document has been prepared by the Regional Resource Center Program ARRA/Fiscal Priority Team to aid RRCP State Liaisons and other (Technical Assistance) TA providers in understanding the general context of state questions surrounding excess cost. As a "first-stop" for TA providers in investigating excess cost…

  9. Removal of Heavy Metals and PAH in Highway Detention Ponds

    DEFF Research Database (Denmark)

    Bentzen, Thomas Ruby; Larsen, Torben; Thorndahl, Søren Liedtke

    2005-01-01

    , which has been designed according to standard design criteria for several decades. The study will focus on heavy metals (Cd, Cr, Cu, Pb and Zn) and polyaromatic hydrocarbons (PAH). The long-term simulation of input of flow and pollution to the ponds will be a hind cast based on time series of historical......The paper presents some of the first results from a study of the removal of pollutants in highway detention ponds in Denmark. The objective of the study is to set up a procedure for long-term modelling of discharges of pollutants to the environment from the many Danish highway detention ponds...... rainfalls. The modelling will take place in a special version of the MIKE URBAN. The modelling is calibrated and validated on measurements from selected highway catchments. The removal of pollutants in the ponds is studied by local measurements in combination with CFD modelling using the MIKE 21 and MIKE 3...

  10. Remediation of PAH-contaminated soil using Achromobacter sp

    International Nuclear Information System (INIS)

    Cutright, T.J.; Lee, S.

    1994-01-01

    Several technologies have the potential to effectively remediate soil contaminated with polycyclic aromatic hydrocarbons (PAHs): solvent extraction, coal-oil agloflotation, supercritical extraction, and bioremediation. Due to the cost effectiveness and in-situ treatment capabilities of bioremediation, studies were conducted to determine the efficiency of Achromobacter sp. to remediate an industrial contaminated soil sample. Specifically, the use of three different mineral salt solutions in conjunction with the Achromobacter sp. was investigated. The molecular identification of the contaminants and their respective levels after remediation were determined using a Hewlett-Packard 1050 HPLC. Preliminary results show a 92% remediation for the use of two of the mineral salt solutions after 20 days' treatment. After 8 weeks, the remediation efficiency reached 99%. Bioremediation was also critically compared to the other potential remediation technologies

  11. Extragalactic infrared astronomy

    International Nuclear Information System (INIS)

    Gondhalekar, P.M.

    1985-05-01

    The paper concerns the field of Extragalactic Infrared Astronomy, discussed at the Fourth RAL Workshop on Astronomy and Astrophysics. Fifteen papers were presented on infrared emission from extragalactic objects. Both ground-(and aircraft-) based and IRAS infrared data were reviewed. The topics covered star formation in galaxies, active galactic nuclei and cosmology. (U.K.)

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

    Science.gov (United States)

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

    2018-03-01

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

  13. Accumulation of policyclic aromatic hydrocarbons (PAHs) in surface litter and soils in four forests in the United States

    Science.gov (United States)

    Obrist, D.; Perlinger, J. A.; Zielinska, B.

    2014-12-01

    Polycyclic aromatic hydrocarbons (PAHs) are toxic environmental pollutants originating from the incomplete combustion of organic material, both from natural or anthropogenic sources. Once emitted, they can be transported across thousands of kilometers impacting remote environments. Here, we characterize the distribution of 23 PAHs and 9 oxygenated PAHs (Σ32PAH) in litter and soils in four remote forests in the United States. Concentrations of Σ32PAH in fresh surface litter (Oi layers) showed very low levels in three of the four forests (mixed coniferous forest in Maine, deciduous blue oak forest in California, and a coniferous forest in Washington State), with PAHs levels much lower than those reported in previous studies from Europe. The analysis showed that PAHs represented a mix of regional background sources. Highest PAH levels were observed in a coniferous forest floor in Florida, attributable to frequent prescribed burning of understory vegetation at this site, and supported by high contributions of retene (>7%; compared to atmospheric deposition. Within mineral soils, Σ32PAH:OC ratios increased with depth (Ah horizons: 750±198 ng g-1; B horizons: 1,202±97 ng g-1), indicating that vertical transfer in mineral soils leads to significant accumulation of PAH in subsoils. ΣPAH:OC increases observed in deeper soil layers may be attributed to slower mineralization rates of PAHs compared to OC, plus vertical transport as indicated by preferential enrichment of PAHs with low Kow (i.e., more water-soluble PAHs). Finally, percentage of potentially biologically produced PAH (Σ Naph+Phen+Pery) were low and consistent across the litter/soil horizons, suggesting that biological production is minor or absent at our sites.

  14. Polycyclic aromatic hydrocarbons (PAHs), their transfer into and dislocation within soil; Eintraege von polyzyklischen aromatischen Kohlenwasserstoffen (PAH) und ihre Verlagerung im Boden

    Energy Technology Data Exchange (ETDEWEB)

    Duerbeck, H W; Niehaus, R; Mueller, U; Bueker, I [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Angewandte Physikalische Chemie

    1998-12-31

    In order to assess the terrestrial hazard potential of polycyclic aromatic hydrocarbons (PAHs), it is vital to investigate their nuisance concentrations and deposition to soil and plants as well as their dislocation in soil. This was the object of the first part of the research programme ``Locational evaluation of chemical soil pollution``, conducted by the national research institutions. It was headed ``Analysis of exposure`` and comprised the following individual contributions: 1. Integrated long-term measurements of polycyclic aromatic hydrocarbons in soil air at ground level (FZJ), 2. Determination of PAH nuisance concentrations at the Scheyern experimental station as well as at the motorway by-passing Munich to the east (A 99), near Kirchheim (GSF), 3. Investigations regarding PAH exposure via the air pathway and inclusion of acquired data in substance flows made up for the east-German dry zone (Bad Lauchstaedt), (UFZ), 4. Simulation of PAH concentration and deposition in south-western Germany (FZK). (orig./SR) [Deutsch] Zur Abschaetzung des Gefaehrdungspotentials von Polycyclischen Aromatischen Kohlenwasserstoffen (PAK) im terrestrischen Bereich sind daher Untersuchungen ueber die Immissionskonzentrationen und die Deposition auf Boeden und Pflanzen sowie ueber ihre Verlagerung im Boden von essentieller Bedeutung. Die Bearbeitung dieser Thematik erfolgte im Teilbereich I `Eintragsanalyse` des AGF-Programms `Standortgerechte Bewertung chemischer Bodenbelastungen` mit folgenden Einzelbeitraegen: 1. Integrierende Langzeitmessung von Polycyclischen Aromatischen Kohlenwasserstoffen in bodennaher Luft, (FZJ) 2. Bestimmung der PAH-Immissionskonzentrationen am Versuchsgut Scheyern sowie an der oestlichen Autobahnumgehung von Muenchen (A 99) bei Kirchheim, (GSF) 3. Untersuchungen zum Eintrag von PAH ueber den Luftpfad und Einbeziehung der Daten in Stoffkreislaeufe im Mitteldeutschen Trockengebiet (Bad Lauchstaedt), (UFZ) 4. Simulation der PAH-Konzentration und

  15. Response of PAH-degrading genes to PAH bioavailability in the overlying water, suspended sediment, and deposited sediment of the Yangtze River.

    Science.gov (United States)

    Xia, Xinghui; Xia, Na; Lai, Yunjia; Dong, Jianwei; Zhao, Pujun; Zhu, Baotong; Li, Zhihuang; Ye, Wan; Yuan, Yue; Huang, Junxiong

    2015-06-01

    The degrading genes of hydrophobic organic compounds (HOCs) serve as indicators of in situ HOC degradation potential, and the existing forms and bioavailability of HOCs might influence the distribution of HOC-degrading genes in natural waters. However, little research has been conducted to study the relationship between them. In the present study, nahAc and nidA genes, which act as biomarkers for naphthalene- and pyrene-degrading bacteria, were selected as model genotypes to investigate the response of polycyclic aromatic hydrocarbon (PAH)-degrading genes to PAH bioavailability in the overlying water, suspended sediment (SPS), and deposited sediment of the Yangtze River. The freely dissolved concentration, typically used to reflect HOC bioavailability, and total dissolved, as well as sorbed concentrations of PAHs were determined. Phylogenetic analysis showed that all the PAH-ring hydroxylating dioxygenase gene sequences of Gram-negative bacteria (PAH-RHD[GN]) were closely related to nahAc, nagAc, nidA, and uncultured PAH-RHD genes. The PAH-RHD[GN] gene diversity as well as nahAc and nidA gene copy numbers decreased in the following order: deposited sediment>SPS>overlying water. The nahAc and nidA gene abundance was not significantly correlated with environmental parameters but was significantly correlated with the bioavailable existing forms of naphthalene and pyrene in the three phases. The nahAc gene copy numbers in the overlying water and deposited sediment were positively correlated with freely dissolved naphthalene concentrations in the overlying and pore water phases, respectively, and so were nidA gene copy numbers. This study suggests that the distribution and abundance of HOC-degrading bacterial population depend on the HOC bioavailability in aquatic environments. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Polycyclic aromatic hydrocarbons (PAHs), their transfer into and dislocation within soil; Eintraege von polyzyklischen aromatischen Kohlenwasserstoffen (PAH) und ihre Verlagerung im Boden

    Energy Technology Data Exchange (ETDEWEB)

    Duerbeck, H.W.; Niehaus, R.; Mueller, U.; Bueker, I. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Angewandte Physikalische Chemie

    1997-12-31

    In order to assess the terrestrial hazard potential of polycyclic aromatic hydrocarbons (PAHs), it is vital to investigate their nuisance concentrations and deposition to soil and plants as well as their dislocation in soil. This was the object of the first part of the research programme ``Locational evaluation of chemical soil pollution``, conducted by the national research institutions. It was headed ``Analysis of exposure`` and comprised the following individual contributions: 1. Integrated long-term measurements of polycyclic aromatic hydrocarbons in soil air at ground level (FZJ), 2. Determination of PAH nuisance concentrations at the Scheyern experimental station as well as at the motorway by-passing Munich to the east (A 99), near Kirchheim (GSF), 3. Investigations regarding PAH exposure via the air pathway and inclusion of acquired data in substance flows made up for the east-German dry zone (Bad Lauchstaedt), (UFZ), 4. Simulation of PAH concentration and deposition in south-western Germany (FZK). (orig./SR) [Deutsch] Zur Abschaetzung des Gefaehrdungspotentials von Polycyclischen Aromatischen Kohlenwasserstoffen (PAK) im terrestrischen Bereich sind daher Untersuchungen ueber die Immissionskonzentrationen und die Deposition auf Boeden und Pflanzen sowie ueber ihre Verlagerung im Boden von essentieller Bedeutung. Die Bearbeitung dieser Thematik erfolgte im Teilbereich I `Eintragsanalyse` des AGF-Programms `Standortgerechte Bewertung chemischer Bodenbelastungen` mit folgenden Einzelbeitraegen: 1. Integrierende Langzeitmessung von Polycyclischen Aromatischen Kohlenwasserstoffen in bodennaher Luft, (FZJ) 2. Bestimmung der PAH-Immissionskonzentrationen am Versuchsgut Scheyern sowie an der oestlichen Autobahnumgehung von Muenchen (A 99) bei Kirchheim, (GSF) 3. Untersuchungen zum Eintrag von PAH ueber den Luftpfad und Einbeziehung der Daten in Stoffkreislaeufe im Mitteldeutschen Trockengebiet (Bad Lauchstaedt), (UFZ) 4. Simulation der PAH-Konzentration und

  17. Use of compound-specific stable carbon isotope ratio measurements of asphaltene-bound polycyclic aromatic hydrocarbons (PAHs) as a novel aid to source apportionment of environmental PAHs

    Energy Technology Data Exchange (ETDEWEB)

    C. Sun; C. Snape; M. Cooper; W. Ivwurie [University of Nottingham, Nottingham (United Kingdom). Nottingham Energy & Fuel Centre

    2005-07-01

    In this study, the PAHs from hydropyrolysis of asphaltenes from different primary sources (e.g. crude oil, low and high temperature coal tars) were characterized by their molecular distributions and {sup 13}C/{sup 12}C isotope ratios. It was found that for all oil samples, the molecular and isotopic profiles for their asphaltene-derived PAHs are both similar to those observed for their contained free aromatics, with {sup 13}C-isotopic values varying from -25 to -27{per_thousand} for the Nigerian and -27 to -30{per_thousand} for North Sea oil samples. For low and high temperature coal tar samples, however, similar molecular but different isotopic profiles were observed for their asphaltene-bound PAHs. The free aromatics are significantly isotopically lighter (by nearly -3{per_thousand}) than their asphaltene-derived counterparts having isotopic values typically between -22 and -23{per_thousand} for all coal tar samples examined, and this leads to a larger isotopic difference of up to 7{per_thousand} between the two sources of PAHs than that already observed between their free aromatics (3{per_thousand}). Applying these results to samples previously examined in an area where unambiguous source apportionment could not be conducted for the PAHs due to likely biodegradation, it was found that the bound PAHs released from the asphaltenes recovered from the soil samples in this area are extremely similar to low temperature tar as the source, in terms of their both molecular (highly alkylated) and isotopic profiles. The free PAHs are much less alkyl substituted confirming that the aromatics detected in this area have been subjected to intensiveenvironmental degradation with alkylated aromatic constituents being preferentially removed from their initial matrix.

  18. The ir emission features: Emission from PAH (Polycyclic Aromatic Hydrocarbons) molecules and amorphous carbon particles

    Energy Technology Data Exchange (ETDEWEB)

    Allamandola, L.J.; Tielens, A.G.G.M.; Barker, J.R.

    1986-01-01

    PAHs can have several forms in the interstellar medium. To assess the importance of each requires the availability of a collection of high quality, complete mid-ir interstellar emission spectra, a collection of laboratory spectra of PAH samples prepared under realistic conditions and a firm understanding of the microscopic emission mechanism. Given what we currently know about PAHs, the spectroscopic data suggests that there are at least two components which contribute to the interstellar emission spectrum: free molecule sized PAHs producing the narrow features and amorphous carbon particles (which are primarily made up of an irregular ''lattice'' of PAHs) contributing to the broad underlying components. An exact treatment of the ir fluorescence from highly vibrationally excited large molecules shows that species containing between 20 and 30 carbon atoms are responsible for the narrow features, although the spectra match more closely with the spectra of amorphous carbon particles. Since little is known about the spectroscopic properties of free PAHs and PAH clusters, much laboratory work is called for in conjunction with an observational program which focuses on the spatial characteristics of the spectra. In this way the distribution and evolution of carbon from molecule to particle can be traced. 38 refs., 9 figs.

  19. Long-term assessment of natural attenuation: statistical approach on soils with aged PAH contamination.

    Science.gov (United States)

    Ouvrard, Stéphanie; Chenot, Elodie-Denise; Masfaraud, Jean-François; Schwartz, Christophe

    2013-07-01

    Natural attenuation processes valorization for PAH-contaminated soil remediation has gained increasing interest from site owners. A misunderstanding of this method and a small amount of data available does not encourage its development. However, monitored natural attenuation (MNA) offers a valuable, cheaper and environmentally friendly alternative to more classical options such as physico-chemical treatments (e.g., chemical oxidation, thermal desorption). The present work proposes the results obtained during a long-term natural attenuation assessment of historically contaminated industrial soils under real climatic conditions. This study was performed after a 10 year natural attenuation period on 60 off-ground lysimeters filled with contaminated soils from different former industrial sites (coking industry, manufactured gas plants) whose initial concentration of PAH varied between 380 and 2,077 mg kg(-1). The analysed parameters included leached water characterization, soil PAH concentrations, evaluation of vegetation cover quality and quantity. Results showed a good efficiency of the PAH dissipation and limited transfer of contaminants to the environment. It also highlighted the importance of the fine soil fractions in controlling PAH reactivity. PAH dissipation through water leaching was limited and did not present a significant risk for the environment. This PAH water concentration appeared however as a good indicator of overall dissipation rate, thereby illustrating the importance of pollutant availability in predicting its degradation potential.

  20. PAHs underfoot: Contaminated dust from coal-tar sealcoated pavement is widespread in the United States

    Science.gov (United States)

    Van Metre, P.C.; Mahler, B.J.; Wilson, J.T.

    2009-01-01

    We reported in 2005 that runoff from parking lots treated with coal-tar-based sealcoat was a major source of polycyclic aromatic hydrocarbons (PAHs) to streams in Austin, Texas. Here we present new data from nine U. S. cities that show nationwide patterns in concentrations of PAHs associated with sealcoat Dust was swept from parking lots in six cities in the central and eastern U. S., where coal-tar-based sealcoat dominates use, and three cities in the western U. S., where asphalt-based sealcoat dominates use. For six central and eastern cities, median ?? PAH concentrations in dust from sealcoated and unsealcoated pavement are 2200 and 27 mg/kg, respectively. For three western cities, median ?? PAH concentrations in dust from sealcoated and unsealcoated pavement are similar and very low (2. 1 and 0. 8 mg/kg, respectively). Lakes in the central and eastern cities where pavement was sampled have bottom sediments with higher PAH concentrations than do those in the western cities relative to degree of urbanization. Bottom-sediment PAH assemblages are similar to those of sealcoated pavement dust regionally, implicating coal-tar-based sealcoat as a PAH source to the central and eastern lakes. Concentrations of benzo[a]pyrene in dust from coal-tar sealcoated pavement and adjacent soils greatly exceed generic soil screening levels, suggesting that research on human-health risk is warranted.

  1. Incidence of real-world automotive parent and halogenated PAH in urban atmosphere.

    Science.gov (United States)

    Gao, Pan-Pan; Zhao, Yi-Bo; Ni, Hong-Gang

    2018-06-01

    This study reports results from a tunnel experiment impact of real-world traffic-related particle and gas parent and halogenated polycyclic aromatic hydrocarbons (PAHs and HPAHs) on urban air. The traffic related emission characteristics and subsequent environmental behavior of these compounds were investigated. To understand the significance of real-world transport emissions to the urban air, traffic-related mass emissions of PAHs and HPAHs were estimated based on measured emission factors. According to our results, PAHs and HPAHs emissions via particulate phase were greater than those via gaseous phase; particles in 2.1-3.3 μm size fraction, have the major contribution to particulate PAHs and HPAHs emissions. Over all, contribution of traffic-related emission of PAHs (only ∼3% of the total PAHs emission in China) is an overstated source of PAHs pollution in China. Actually, exhaust pipe emission contributed much less than the total traffic-related emission of pollutants. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. Mutation Analysis in Classical Phenylketonuria Patients Followed by Detecting Haplotypes Linked to Some PAH Mutations.

    Science.gov (United States)

    Dehghanian, Fatemeh; Silawi, Mohammad; Tabei, Seyed M B

    2017-02-01

    Deficiency of phenylalanine hydroxylase (PAH) enzyme and elevation of phenylalanine in body fluids cause phenylketonuria (PKU). The gold standard for confirming PKU and PAH deficiency is detecting causal mutations by direct sequencing of the coding exons and splicing involved sequences of the PAH gene. Furthermore, haplotype analysis could be considered as an auxiliary approach for detecting PKU causative mutations before direct sequencing of the PAH gene by making comparisons between prior detected mutation linked-haplotypes and new PKU case haplotypes with undetermined mutations. In this study, 13 unrelated classical PKU patients took part in the study detecting causative mutations. Mutations were identified by polymerase chain reaction (PCR) and direct sequencing in all patients. After that, haplotype analysis was performed by studying VNTR and PAHSTR markers (linked genetic markers of the PAH gene) through application of PCR and capillary electrophoresis (CE). Mutation analysis was performed successfully and the detected mutations were as follows: c.782G>A, c.754C>T, c.842C>G, c.113-115delTCT, c.688G>A, and c.696A>G. Additionally, PAHSTR/VNTR haplotypes were detected to discover haplotypes linked to each mutation. Mutation detection is the best approach for confirming PAH enzyme deficiency in PKU patients. Due to the relatively large size of the PAH gene and high cost of the direct sequencing in developing countries, haplotype analysis could be used before DNA sequencing and mutation detection for a faster and cheaper way via identifying probable mutated exons.

  3. Human mesenchymal stem cell osteoblast differentiation, ECM deposition, and biomineralization on PAH/PAA polyelectrolyte multilayers.

    Science.gov (United States)

    Pattabhi, Sudhakara Rao; Lehaf, Ali M; Schlenoff, Joseph B; Keller, Thomas C S

    2015-05-01

    Polyelectrolyte multilayer (PEMU) coatings built layer by layer with alternating pairs of polyelectrolytes can be tuned to improve cell interactions with surfaces and may be useful as biocompatible coatings to improve fixation between implants and tissues. Here, we show that human mesenchymal stromal cells (hMSCs) induced with bone differentiation medium (BDM) to become osteoblasts biomineralize crosslinked PEMUs built with the polycation poly(allylamine hydrochloride) (PAH) and the polyanion poly(acrylic acid) (PAA). Degrees of hMSC osteoblast differentiation and surface biomineralization on the smooth PAH-terminated PEMUs (PAH-PEMUs) and microstructured PAA-terminated PEMUs (PAA-PEMUs) reflect differences in cell-deposited extracellular matrix (ECM). BDM-induced hMSCs expressed higher levels of the early osteoblast differentiation marker alkaline phosphatase and collagen 1 (COL1) sooner on PAA-PEMUs than on PAH-PEMUs. Cells on both types of PEMUs proceeded to express the later stage osteoblast differentiation marker bone sialoprotein (BSP), but the BDM-induced cells organized a more amorphous Collagen I and denser BSP localization on PAA-PEMUs than on PAH-PEMUs. These ECM properties correlated with greater biomineralization on the PAA-PEMUs than on PAH-PEMUs. Together, these results confirm the suitability of PAH/PAA PEMUs as a substrate for hMSC osteogenesis and highlight the importance of substrate effects on ECM organization and BSP presentation on biomineralization. © 2014 Wiley Periodicals, Inc.

  4. The ir emission features: Emission from PAH [Polycyclic Aromatic Hydrocarbons] molecules and amorphous carbon particles

    International Nuclear Information System (INIS)

    Allamandola, L.J.; Tielens, A.G.G.M.; Barker, J.R.

    1986-01-01

    PAHs can have several forms in the interstellar medium. To assess the importance of each requires the availability of a collection of high quality, complete mid-ir interstellar emission spectra, a collection of laboratory spectra of PAH samples prepared under realistic conditions and a firm understanding of the microscopic emission mechanism. Given what we currently know about PAHs, the spectroscopic data suggests that there are at least two components which contribute to the interstellar emission spectrum: free molecule sized PAHs producing the narrow features and amorphous carbon particles (which are primarily made up of an irregular ''lattice'' of PAHs) contributing to the broad underlying components. An exact treatment of the ir fluorescence from highly vibrationally excited large molecules shows that species containing between 20 and 30 carbon atoms are responsible for the narrow features, although the spectra match more closely with the spectra of amorphous carbon particles. Since little is known about the spectroscopic properties of free PAHs and PAH clusters, much laboratory work is called for in conjunction with an observational program which focuses on the spatial characteristics of the spectra. In this way the distribution and evolution of carbon from molecule to particle can be traced. 38 refs., 9 figs

  5. Treatment of PAH-contaminated soil using cement-activated persulfate.

    Science.gov (United States)

    Ma, Fujun; Zhang, Qian; Wu, Bin; Peng, Changsheng; Li, Ning; Li, Fasheng; Gu, Qingbao

    2018-01-01

    In this study, a novel method for the treatment of polycyclic aromatic hydrocarbon -contaminated soil using cement-activated persulfate was developed. The removal of PAHs in soil rose with increasing initial persulfate concentration, initial Portland cement (PC) concentration, and oxidation reaction time. At an initial persulfate and PC concentration of 19.20 mmol/kg and 10% of soil weight and a reaction time of 2 h, the removal rate of PAHs reached 57.3%. Residual PAHs were mainly adsorbed within the soil granules and thus became less available. The mechanism of PC facilitating the oxidation reaction was that PC addition can increase the pH and temperature of the system. When the soil was stabilized/solidified by 10% of PC, the leaching concentration of PAHs and TOC was significantly higher than that leached from untreated soil. Persulfate oxidation decreased the leaching concentration of PAHs but increased the leaching concentration of TOC in solidification/stabilization products. The addition of activated carbon can decrease the leaching concentrations of both PAHs and TOC. Freeze-thaw durability tests revealed that the leachability of PAHs was not affected by freeze-thaw cycles. The unconfined compressive strength (UCS) of treated soil samples after 12 freeze-thaw cycles was only 49.0% of that curing for 52 days, but the UCS was still > 1 MPa. The treated soil samples can resist disintegration during the process of freeze-thaw cycles.

  6. Prediction of HS Soderberg plant PAH emissions from a laboratory evaluation of a pitch

    Energy Technology Data Exchange (ETDEWEB)

    Castonguay, L.; Mirtchi, A. A.; Proulx, A. L.; Savard, G.; Simard, E.; Steward, N.; Tremblay, C. [Alcan International Ltd., Arvida Research and Development Centre, Jonquiere, PQ (Canada)

    1998-12-31

    The presence of certain polycyclic aromatic hydrocarbons (PAHs) in coal tar pitch has been identified as a possible limit to the long-term viability of horizontal stud (HS) Soderberg technology, a technology of importance in the aluminum industry. This paper presents the results of a comparative study of pitch PAH content and HS Soderberg cell emissions. Laboratory results are compared with plant emissions for two regular and low PAH pitches with the same softening points. The results indicate the existence of a correlation between pitch PAH content and cell emission, which is valid for regular tar pitches, low tar pitches, as well as for hybrid pitches. These findings make it possible to predict the quantity and distribution of HS Soderberg cell PAH emissions from the analysis of PAHs in the pitch. The results also justify the conclusion that the emission of genotoxic compounds from pitch in the HS Soderberg technology can be decreased by using a pitch with low PAH content. 4 refs., 5 tabs., 5 figs.

  7. Growth and Destruction of PAH Molecules in Reactions with Carbon Atoms

    Energy Technology Data Exchange (ETDEWEB)

    Krasnokutski, Serge A.; Huisken, Friedrich; Jäger, Cornelia; Henning, Thomas [Laboratory Astrophysics Group of the Max Planck Institute for Astronomy at the Friedrich Schiller University Jena, Helmholtzweg 3, D-07743 Jena (Germany)

    2017-02-10

    A very high abundance of atomic carbon in the interstellar medium (ISM), and the high reactivity of these species toward different hydrocarbon molecules including benzene, raise questions regarding the stability of polycyclic aromatic hydrocarbon (PAH) molecules in space. To test the efficiency of destruction of PAH molecules via reactions with atomic carbon, we performed a set of laboratory and computational studies of the reactions of naphthalene, anthracene, and coronene molecules with carbon atoms in the ground state. The reactions were investigated in liquid helium droplets at T = 0.37 K and by quantum chemical computations. Our studies suggest that all small and all large catacondensed PAHs react barrierlessly with atomic carbon, and therefore should be efficiently destroyed by such reactions in a broad temperature range. At the same time, large compact pericondensed PAHs should be more inert toward such a reaction. In addition, taking into account their higher photostability, much higher abundances of pericondensed PAHs should be expected in various astrophysical environments. The barrierless reactions between carbon atoms and small PAHs also suggest that, in the ISM, these reactions could lead to the bottom-up formation of PAH molecules.

  8. Hot gas cleaning in power stations by using electron beam technology. Influence on PAH emissions

    International Nuclear Information System (INIS)

    Callen, M.S.; de la Cruz, M.T.; Mastral, A.M.; Murillo, R.; Marinov, S.; Stefanova, M.

    2007-01-01

    The Electron Beam Technology (EBT), proven treatment for SO 2 and NO x removal, is applied to different power stations as a hot gas cleaning system. In this paper, an assessment of this technique installed in a Bulgarian power station on organic emissions is analyzed. The Polycyclic Aromatic Hydrocarbons (PAH) content, not only emitted in the gas phase but also trapped in the solid phase, has been carried out before and after the irradiation. The main aim has been to know whether the EBT affects organic emissions, like PAH, as it happens with inorganic pollutants, like SO 2 and NO x , studying EBT effects from an organic environmental point of view. The PAH quantification was performed by using a very sensitive analytical technique, gas chromatography with mass spectrometry mass spectrometry detection (GC-MS-MS). Results showed that PAH are influenced by the EBT showing a reduction of the most volatile PAH in the gas phase. With regard to the solid by-products obtained after the irradiation, fertilizers, similar PAH concentration to the fly ashes produced when no irradiation is applied were found. These fertilizers were considered like unpolluted soils being adequate for agriculture applications with PAH concentrations below the target value set up by the Dutch government. (author)

  9. Exposure Assessment of Polycyclic Aromatic Hydrocarbon (PAHs) in Childcare Centers of Muang, Nakhon Ratchasima

    Science.gov (United States)

    Jitlada, C.; Pentamwa, P.

    2018-03-01

    This study aims to characterize airborne polycyclic aromatic hydrocarbons (PAHs) as of particulate and vapor phases variation. The samples were collected from the childcare centers where divided into urban and rural areas in Nakhon Ratchasima Province of Thailand. The airborne samples were collected from five childcare centers during the dry season in the year 2017. The PAHs species were determined by the gas chromatography and mass spectroscopy (GS/MS) method. Results show that the total concentrations of PAHs were higher than vapor phase that both similar in urban area and rural area. The dominant PAHs compounds of both urban and rural areas were benzo(a)pyrene, benzo(a,h)anthracene and indeno(1,2,3-cd)pyrene, respectively. Furthermore, the concentrations of PAHs in municipality (urban) childcare centers were higher than rural childcare centers area of Nakhon Ratchasima province. The risks associated with exposure to PAHs were evaluated using the TEF approach. The estimated value of lifetime lung cancer risks children in urban were significantly (p < 0.05) 2 times of children in rural, thus demonstrating that exposure to PAHs at levels found at urban site may be cause potential health risks.

  10. Significance of population centers as sources of gaseous and dissolved PAHs in the lower Great Lakes.

    Science.gov (United States)

    McDonough, Carrie A; Khairy, Mohammed A; Muir, Derek C G; Lohmann, Rainer

    2014-07-15

    Polyethylene passive samplers (PEs) were used to measure concentrations of gaseous and dissolved polycyclic aromatic hydrocarbons (PAHs) in the air and water throughout the lower Great Lakes during summer and fall of 2011. Atmospheric Σ15PAH concentrations ranged from 2.1 ng/m3 in Cape Vincent (NY) to 76.4 ng/m3 in downtown Cleveland (OH). Aqueous Σ18PAH concentrations ranged from 2.4 ng/L at an offshore Lake Erie site to 30.4 ng/L in Sheffield Lake (OH). Gaseous PAH concentrations correlated strongly with population within 3-40 km of the sampling site depending on the compound considered, suggesting that urban centers are a primary source of gaseous PAHs (except retene) in the lower Great Lakes region. The significance of distant population (within 20 km) versus local population (within 3 km) increased with subcooled liquid vapor pressure. Most dissolved aqueous PAHs did not correlate significantly with population, nor were they consistently related to river discharge, wastewater effluents, or precipitation. Air-water exchange calculations implied that diffusive exchange was a source of phenanthrene to surface waters, while acenaphthylene volatilized out of the lakes. Comparison of air-water fluxes with temperature suggested that the significance of urban centers as sources of dissolved PAHs via diffusive exchange may decrease in warmer months.

  11. Assessing PAH removal from clayey soil by means of electro-osmosis and electrodialysis

    KAUST Repository

    Lima, Ana T.

    2012-10-01

    Polycyclic aromatic hydrocarbons (PAH) are persistent and toxic contaminants which are difficult to remove from fine porous material like clayey soils. The present work aims at studying two electroremediation techniques for the removal of PAHs from a spiked natural silt soil from Saudi Arabia and a silty loam soil from The Netherlands which has been exposed to tar contamination for over 100. years. The two techniques at focus are electro-osmosis and electrodialysis. The latter is applied for the first time for the removal of PAH. The efficiency of the techniques is studied using these two soils, having been subjected to different PAH contact times. Two surfactants were used: the non-ionic surfactant Tween 80 and anionic surfactant sodium dodecyl sulphate (SDS) to aid desorption of PAHs from the soil. Results show a large discrepancy in the removal rates between spiked soil and long-term field contaminated soil, as expected. In spiked soil, electro-osmosis achieves up to 85% while electrodialysis accomplishes 68% PAH removal. In field contaminated soil, electro-osmosis results in 35% PAH removal whereas electrodialysis results in 79%. Short recommendations are derived for the up-scale of the two techniques. © 2012.

  12. Bimonthly assessment of PAH content in wild mussels from the Spanish Atlantic Coast

    Directory of Open Access Journals (Sweden)

    Juan Antonio Campillo

    2014-06-01

    Full Text Available During 2013-14 wild mussels were bimonthly sampled in five stations along the Spanish Atlantic coast in order to assess any temporal variation in the concentration of parent PAHs. The sampling stations selected (Oia, Raxó, Mera, Avilés and Pedreña included both polluted and unpolluted sites and tried to reflect the different situations in the area (coastal and more estuarine waters. The samples were shipped to the lab and three homogenates from each site were prepared and frozen until analysis. 13 parent PAHs were quantified using HPLC with fluorescence detection. In general, the highest concentrations were found in the January-March sampling, during the pre-spawning period. PAHs contents were related to mussel biochemical composition, mainly carbohydrates and lipids, and to mussel reproductive stage. In general the 4-ring PAHs is the most abundant group of PAHs. The input of the HMW PAHs (4-5 rings to the total PAH burden generally increases in the winter months probably due to both different sources in that season (building heatings and the remobilization of sediments.

  13. Chemical-assisted phytoremediation of CD-PAHs contaminated soils using Solanum nigrum L.

    Science.gov (United States)

    Yang, Chuanjie; Zhou, Qixing; Wei, Shuhe; Hu, Yahu; Bao, Yanyu

    2011-09-01

    A well-characterized cadmium (Cd) hyperaccumulating plant Solanum nigrum was grown in Cd and polycyclic aromatic hydrocarbons (PAHs) co-contaminated soil that was repeatedly amended with chemicals, including EDTA, cysteine (CY), salicylic acid (Sa), and Tween 80 (TW80), to test individual and combined treatment effects on phytoremediation of Cd-PAHs contaminated soils. Plant growth was negatively affected by exogenous chemicals except for EDTA. S. nigrum could accumulate Cd in tissues without assistant chemicals, while there was no visible effect on the degradation of PAHs. Cysteine had significant effects on phytoextraction of Cd and the highest metal extraction ratio (1.27%) was observed in 0.9 mmol/kg CY treatment. Both salicylic acid and Tween 80 had stimulative effects on the degradation of PAHs and there was the maximal degradation rate (52.6%) of total PAHs while 0.9 mmol/kg Sa was applied. Furthermore, the combined treatment T(0.1EDTA+0.9CY+0.5TW80) and T(0.5EDTA+0.9CY+03Sa) could not only increase the accumulation of Cd in plant tissues, but also promote the degradation of PAHs. These results indicated that S. nigrum might be effective in phytoextracting Cd and enhancing the biodegradation of PAHs in the co-contaminated soils with assistant chemicals.

  14. Assessing PAH removal from clayey soil by means of electro-osmosis and electrodialysis

    KAUST Repository

    Lima, Ana T.; Ottosen, Lisbeth M.; Heister, Katja; Loch, J.P. Gustav

    2012-01-01

    Polycyclic aromatic hydrocarbons (PAH) are persistent and toxic contaminants which are difficult to remove from fine porous material like clayey soils. The present work aims at studying two electroremediation techniques for the removal of PAHs from a spiked natural silt soil from Saudi Arabia and a silty loam soil from The Netherlands which has been exposed to tar contamination for over 100. years. The two techniques at focus are electro-osmosis and electrodialysis. The latter is applied for the first time for the removal of PAH. The efficiency of the techniques is studied using these two soils, having been subjected to different PAH contact times. Two surfactants were used: the non-ionic surfactant Tween 80 and anionic surfactant sodium dodecyl sulphate (SDS) to aid desorption of PAHs from the soil. Results show a large discrepancy in the removal rates between spiked soil and long-term field contaminated soil, as expected. In spiked soil, electro-osmosis achieves up to 85% while electrodialysis accomplishes 68% PAH removal. In field contaminated soil, electro-osmosis results in 35% PAH removal whereas electrodialysis results in 79%. Short recommendations are derived for the up-scale of the two techniques. © 2012.

  15. PAHs in leachates from thermal power plant wastes and ash-based construction materials.

    Science.gov (United States)

    Irha, Natalya; Reinik, Janek; Jefimova, Jekaterina; Koroljova, Arina; Raado, Lembi-Merike; Hain, Tiina; Uibu, Mai; Kuusik, Rein

    2015-08-01

    The focus of the current study is to characterise the leaching behaviour of polycyclic aromatic hydrocarbons (PAHs) from oil shale ashes (OSAs) of pulverised firing (PF) and circulating fluidised-bed (CFB) boilers from Estonian Thermal Power Plant (Estonia) as well as from mortars and concrete based on OSAs. The target substances were 16 PAHs from the EPA priority pollutant list. OSA samples and OSA-based mortars were tested for leaching, according to European standard EN 12457-2 (2002). European standard CEN/TC 15862(2012) for monolithic matter was used for OSA-based concrete. Water extracts were analysed by GC-MS for the concentration of PAHs. Naphthalene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene and pyrene were detected. Still, the release of PAHs was below the threshold limit value for inert waste. The amount of the finest fraction (particle size materials did not lead to the immobilisation of soluble PAHs. Release of PAHs from the monolith samples did not exceed 0.5 μg/m(2). In terms of leaching of PAHs, OSA is safe to be used for construction purposes.

  16. Polycyclic aromatic hydrocarbons (PAHs in the atmospheres of two French alpine valleys: sources and temporal patterns

    Directory of Open Access Journals (Sweden)

    N. Marchand

    2004-01-01

    Full Text Available Alpine valleys represent some of the most important crossroads for international heavy-duty traffic in Europe, but the full impact of this traffic on air quality is not known due to a lack of data concerning these complex systems. As part of the program "Pollution des Vallées Alpines" (POVA, we performed two sampling surveys of polycyclic aromatic hydrocarbons (PAHs in two sensitive valleys: the Chamonix and Maurienne Valleys, between France and Italy. Sampling campaigns were performed during the summer of 2000 and the winter of 2001, with both periods taking place during the closure of the "Tunnel du Mont-Blanc". The first objective of this paper is to describe the relations between PAH concentrations, external parameters (sampling site localization, meteorological parameters, sources, and aerosol characteristics, including its carbonaceous fraction (OC and EC. The second objective is to study the capacity of PAH profiles to accurately distinguish the different emission sources. Temporal evolution of the relative concentration of an individual PAH (CHR and the PAH groups BghiP+COR and BbF+BkF is studied in order to differentiate wood combustion, gasoline, and diesel emissions, respectively. The results show that the total particulate PAH concentrations were higher in the Chamonix valley during both seasons, despite the cessation of international traffic. Seasonal cycles, with higher concentrations in winter, are also stronger in this valley. During winter, particulate PAH concentration can reach very high levels (up to 155 ng.m-3 in this valley during cold anticyclonic periods. The examination of sources shows the impact during summer of heavy-duty traffic in the Maurienne valley and of gasoline vehicles in the Chamonix valley. During winter, Chamonix is characterized by the strong influence of wood combustion in residential fireplaces, even if the temporal evolution of specific PAH ratios are difficult to interpret. Information on sources

  17. Biodegradation of PAHs in petroleum-contaminated soil using tamarind leaves as microbial inoculums

    Directory of Open Access Journals (Sweden)

    Kanchana Juntongjin

    2007-03-01

    Full Text Available Petroleum-contaminated soil contains various hazardous materials such as aromatic hydrocarbons and polycyclic aromatic hydrocarbons (PAHs. This study focused on PAHs since they are potentially toxic,mutagenic, and carcinogenic. Bioremediation of PAHs was carried out by adding tamarind leaf inoculums into petroleum-contaminated soil. Tamarind and other leguminous leaves have been reported to containedseveral PAH-degrading microorganisms. To minimize the amount of leaves added, the preparation of tamarind leaf inoculums was developed by incubating tamarind leaves with a sub-sample of contaminated soil for 49 days. After that, the efficiency of tamarind leaf inoculums was tested with two soil samplescollected from a navy dockyard and railway station in Samutprakarn and Bangkok, respectively. These soil samples had different levels of petroleum contamination. Bioaugmentation treatment was carried out bymixing contaminated soil with the inoculum at the ratio of 9:1. For navy dockyard soil, the concentration of phenanthrene was decreased gradually and reached the undetectable concentration within 56 days in theinoculated soil; meanwhile 70-80% of fluoranthene and pyrene were remained at the end of treatment. For railway station soil, which had lower petroleum contamination, PAH degradation was more rapid, forexample, the concentration of phenanthrene was below detection limit after 28 days. Besides PAHs, the amounts of several hydrocarbons were also reduced after treatment. At the same time, numerousphenanthrene-degrading bacteria, which were used as representatives of PAH degraders, could be observed in both inoculated soils. However, higher numbers of bacteria were found in railway station soil, whichcorresponded with the lower amount of PAHs and higher amount of soil nutrients. The results showed that inoculum prepared from tamarind leaves could be used to degrade PAHs as well as clean-up petroleum contaminated soil.

  18. Exchangeable cations-mediated photodegradation of polycyclic aromatic hydrocarbons (PAHs) on smectite surface under visible light

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Hanzhong, E-mail: jiahz@ms.xjb.ac.cn [Laboratory of Environmental Sciences and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011 (China); Li, Li [Laboratory of Environmental Sciences and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011 (China); Chen, Hongxia; Zhao, Yue [Laboratory of Environmental Sciences and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011 (China); School of Geology and Mining Engineering, Xinjiang University, Urumqi 830046 (China); Li, Xiyou [Laboratory of Environmental Sciences and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011 (China); Wang, Chuanyi, E-mail: cywang@ms.xjb.ac.cn [Laboratory of Environmental Sciences and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011 (China)

    2015-04-28

    Graphical abstract: Roles of exchangeable cations in PAHs photodegradation on clay surafces under visible light. - Highlights: • Photolysis rate are strongly dependent on the type of cations on clay surface. • The strength of “cation–π” interactions governs the photodegradation rate of PAHs. • Several exchangeable cations could cause a shift in the absorption spectrum of PAHs. • Exchangeable cations influence the type and amount of reactive intermediates. - Abstract: Clay minerals saturated with different exchangeable cations are expected to play various roles in photodegradation of polycyclic aromatic hydrocarbons (PAHs) via direct and/or indirect pathways on clay surfaces. In the present study, anthracene and phenanthrene were selected as molecule probes to investigate the roles of exchangeable cations on their photodegradation under visible light irradiation. For five types of cation-modified smectite clays, the photodegradation rate of anthracene and phenanthrene follows the order: Fe{sup 3+} > Al{sup 3+} > Cu{sup 2+} >> Ca{sup 2+} > K{sup +} > Na{sup +}, which is consistent with the binding energy of cation–π interactions between PAHs and exchangeable cations. The result suggests that PAHs photolysis rate depends on cation–π interactions on clay surfaces. Meanwhile, the deposition of anthracene at the Na{sup +}-smectite and K{sup +}-smectite surface favors solar light absorption, resulting in enhanced direct photodecomposition of PAHs. On the other hand, smectite clays saturated with Fe{sup 3+}, Al{sup 3+}, and Cu{sup 2+} are highly photoreactive and can act as potential catalysts giving rise to oxidative radicals such as O{sub 2}{sup −}· , which initiate the transformation of PAHs. The present work provides valuable insights into understanding the transformation and fate of PAHs in the natural soil environment and sheds light on the development of technologies for contaminated land remediation.

  19. VUV photo-processing of PAH cations: quantitative study on the ionization versus fragmentation processes

    Science.gov (United States)

    Zhen, Junfeng; Castillo, Sarah Rodriguez; Joblin, Christine; Mulas, Giacomo; Sabbah, Hassan; Giuliani, Alexandre; Nahon, Laurent; Martin, Serge; Champeaux, Jean-Philippe; Mayer, Paul M.

    2016-01-01

    Interstellar polycyclic aromatic hydrocarbons (PAHs) are strongly affected by the absorption of vacuum ultraviolet (VUV) photons in the interstellar medium (ISM), yet the branching ratio between ionization and fragmentation is poorly studied. This is crucial for the stability and charge state of PAHs in the ISM in different environments, affecting in turn the chemistry, the energy balance, and the contribution of PAHs to the extinction and emission curves. We studied the interaction of PAH cations with VUV photons in the 7 – 20 eV range from the synchrotron SOLEIL beamline, DESIRS. We recorded by action spectroscopy the relative intensities of photo-fragmentation and photo-ionization for a set of eight PAH cations ranging in size from 14 to 24 carbon atoms, with different structures. At photon energies below ~13.6 eV fragmentation dominates for the smaller species, while for larger species ionization is immediately competitive after the second ionization potential (IP). At higher photon energies, all species behave similarly, the ionization yield gradually increases, leveling off between 0.8 and 0.9 at ~18 eV. Among isomers, PAH structure appears to mainly affect the fragmentation cross section, but not the ionization cross section. We also measured the second IP for all species and the third IP for two of them, all are in good agreement with theoretical ones confirming that PAH cations can be further ionized in the diffuse ISM. Determining actual PAH dication abundances in the ISM will require detailed modeling. Our measured photo-ionization yields for several PAH cations provide a necessary ingredient for such models. PMID:27212712

  20. Interactions between selected PAHs and the microbial community in rhizosphere of a paddy soil.

    Science.gov (United States)

    Su, Yu H; Yang, Xue Y

    2009-01-15

    This study investigated the interaction of three polycyclic aromatic hydrocarbons (PAHs), i.e., naphthalene (NAP), phenanthrene (PHN), and pyrene (PYR), with the microbial community in the rhizosphere of a paddy soil and the influence of the rice (Oryza sativa) rhizosphere on the microbial community structure. A range of initial NAP, PHN and PYR levels in soil (50-200, 18-72, and 6.6-26.6 mg kg(-1), respectively) were prepared and the soil samples were then aged for 4 months (to yield PAH concentrations at 1.02-1.42, 1.32-4.77, and 2.98-18.5 mg kg(-)(1), respectively) before the soil samples were planted with rice seedlings. The microbial phospholipid-fatty-acid (PLFA) patterns in PAH-contaminated soils were analyzed to elucidate the changes of the microbial biomass and community composition. Results indicated that at the applied concentrations the PAHs were not toxic to rice seedlings, as evidenced by no growth inhibition during the 8-week planting period. However, the microbial biomass, as revealed by PLFAs, decreased significantly with increasing PAH concentration in both rhizospheric and non-rhizospheric soils. The PAHs in soils were obviously toxic to microorganisms, and the toxicity of PHN was greater than PYR due likely to the higher PHN bioavailability. Total PLFAs in rhizospheric soils were profoundly higher than those in non-rhizospheric soils, suggesting that the inhibitive effect of PAHs on microbial activities was alleviated by the rice roots. The principal component analysis (PCA) of the PLFA signatures revealed pronounced changes in PLFA pattern in rhizospheric and non-rhizospheric soils with or without spiked PAHs. Using the PLFA patterns as a biomarker, it was found that Gram-positive bacteria were more sensitive to PAHs than Gram-negative bacteria, and the rhizosphere of rice roots stimulated the growth of aerobic bacteria.

  1. Evaluation of polyurethane foam passive air sampler (PUF) as a tool for occupational PAH measurements.

    Science.gov (United States)

    Strandberg, Bo; Julander, Anneli; Sjöström, Mattias; Lewné, Marie; Koca Akdeva, Hatice; Bigert, Carolina

    2018-01-01

    Routine monitoring of workplace exposure to polycyclic aromatic hydrocarbons (PAHs) is performed mainly via active sampling. However, active samplers have several drawbacks and, in some cases, may even be unusable. Polyurethane foam (PUF) as personal passive air samplers constitute good alternatives for PAH monitoring in occupational air (8 h). However, PUFs must be further tested to reliably yield detectable levels of PAHs in short exposure times (1-3 h) and under extreme occupational conditions. Therefore, we compared the personal exposure monitoring performance of a passive PUF sampler with that of an active ai