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Sample records for alkylated polycyclic aromatic

  1. Alkyl polycyclic aromatic hydrocarbons emissions in diesel/biodiesel exhaust

    NASA Astrophysics Data System (ADS)

    Casal, Carina S.; Arbilla, Graciela; Corrêa, Sergio M.

    2014-10-01

    Polycyclic aromatic hydrocarbons (PAHs) are widely studied in environmental matrices, such as air, water, soil and sediment, because of their toxicity, mutagenicity and carcinogenicity. Because of these properties, the environmental agencies of developed countries have listed sixteen PAHs as priority pollutants. Few countries have limits for these compounds for ambient air, but they only limit emissions from stationary and mobile sources and occupational areas. There are several studies to specifically address the 16 priority PAHs and very little for the alkyl PAHs. These compounds are more abundant, more persistent and frequently more toxic than the non-alkylated PAHs, and the toxicity increases with the number of alkyl substitutions on the aromatic ring. In this study, a method was developed for the analysis of PAHs and alkyl PAHs by using a GC-MS and large injection volume injection coupled with program temperature vaporisation, which allows for limits of detection below 1.0 ng μL-1. Several variables were tested, such as the injection volume, injection velocity, injector initial temperature, duration of the solvent split and others. This method was evaluated in samples from particulate matter from the emissions of engines employing standard diesel, commercial diesel and biodiesel B20. Samples were collected on a dynamometer bench for a diesel engine cycle and the results ranged from 0.5 to 96.9 ng mL-1, indicating that diesel/biodiesel makes a significant contribution to the formation of PAHs and alkyl PAHs.

  2. Distributions of polycyclic aromatic hydrocarbons and alkylated polycyclic aromatic hydrocarbons in Osaka Bay, Japan.

    PubMed

    Miki, Shizuho; Uno, Seiichi; Ito, Kazuki; Koyama, Jiro; Tanaka, Hiroyuki

    2014-08-30

    Contaminations in sediments by polycyclic aromatic hydrocarbons (PAHs) and alkylated PAHs were investigated at 44 sites in Osaka Bay, Japan. Concentrations of total PAHs and alkylated PAHs were in the range 6.40-7800 ng/g dry weights and 13.7-1700 ng/g dry weights, respectively. The PAH concentrations tended to be higher along the shoreline in the vicinities of big ports, industrialized areas, and densely populated regions such as the cities of Osaka and Kobe. The major sources appeared to be pyrogenic or both pyrogenic and petrogenic at most of the sites. PAH concentrations were remarkably high at a site near Kobe, where the concentrations of dibenzo(a,h)anthracene and benzo(g,h,i)perylene exceeded the effects-range-medium concentration and eight PAHs were above the corresponding effects-range-low concentrations. Those PAHs may have been derived from the great fire associated with the large earthquake in 1995.

  3. EPR and DFT Study of the Polycyclic Aromatic Radical Cations from Friedel-Crafts Alkylation Reactions

    NASA Astrophysics Data System (ADS)

    Wang, Tao; Wu, An-an; Gao, Li-guo; Wang, Han-qing

    2009-02-01

    Electron paramagnetic resonance and electron-nuclear double resonance methods were used to study the polycyclic aromatic radical cations produced in a Friedel-Crafts alkylating system, with m-xylene, or p-xylene and alkyl chloride. The results indicate that the observed electron paramagnetic resonance spectra are due to polycyclic aromatic radicals formed from the parent hydrocarbons. It is suggested that benzyl halides produced in the Friedel-Crafts alkylation reactions undergo Scholl self-condensation to give polycyclic aromatic hydrocarbons, which are converted into corresponding polycyclic aromatic radical cations in the presence of AlCl3. The identification of observed two radicals 2,6-dimethylanthracene and 1,4,5,8-tetramethylanthracene were supported by density functional theory calculations using the B3LYP/6-31G(d,p)//B3LYP/6-31G(d) approach. The theoretical coupling constants support the experimental assignment of the observed radicals.

  4. Retention behavior of alkyl-substituted polycyclic aromatic sulfur heterocycles in reversed-phase liquid chromatography.

    PubMed

    Wilson, Walter B; Sander, Lane C; de Alda, Miren Lopez; Lee, Milton L; Wise, Stephen A

    2016-08-26

    Retention indices for 79 alkyl-substituted polycyclic aromatic sulfur heterocycles (PASHs) were determined by using reversed-phase liquid chromatography (LC) on a monomeric and polymeric octadecylsilane (C18) stationary phase. Molecular shape parameters [length, breadth, thickness (T), and length-to-breadth ratio (L/B)] were calculated for all the compounds studied. Based on separations of isomeric methylated polycyclic aromatic hydrocarbons on polymeric C18 phases, alkyl-substituted PASHs are expected to elute based on increasing L/B ratios. However, the correlation coefficients had a wide range of values from r=0.43 to r=0.93. Several structural features besides L/B ratios were identified to play an important role in the separation mechanism of PASHs on polymeric C18 phases. First, the location of the sulfur atom in a bay-like-region results in alkylated-PASHs being more retentive than non-bay-like-region alkylated-PASHs, and they elute later than expected based on L/B value. Second, the placement of the alkyl group in the k region of the structure resulted in a later elution than predicted by L/B. Third, highly nonplanar methyl-PASHs (i.e., 1-Me and 11-MeBbN12T) elute prior to the parent PASH (BbN12T).

  5. Physico-chemical properties and toxicity of alkylated polycyclic aromatic hydrocarbons.

    PubMed

    Kang, Hyun-Joong; Lee, So-Young; Kwon, Jung-Hwan

    2016-07-15

    Crude oil and refined petroleum products contain many polycyclic and heterocyclic aromatic hydrocarbons, in particular, alkylated PAHs. Although alkylated PAHs are found in significantly higher quantities than their corresponding unsubstituted PAHs, the most studies on the physico-chemical properties and toxicities of these compounds have been conducted on unsubstituted PAHs. In this study, we measured crucial physico-chemical properties (i.e., water solubility, partition coefficients between polydimethylsiloxane and water (KPDMSw), and partition coefficient between liposomes and water (Klipw)) of selected alkylated PAHs, and evaluated their toxicity using the luminescence inhibition of Aliivibrio fischeri and growth inhibition of Raphidocelis subcapitata. In general, the logarithms of these properties for alkylated PAHs showed good linear correlations with log Kow, as did those for unsubstituted PAHs. Changes in molecular symmetry on the introduction of alkyl groups on aromatic ring structure significantly altered water solubility. The inhibition of bacterial luminescence and algal growth by alkylated PAHs can be explained well by the baseline toxicity hypothesis, and good linear relationships between log Kow or log Klipw and log (1/EC50) were found.

  6. Polyethylene-water partitioning coefficients for parent- and alkylated-polycyclic aromatic hydrocarbons and polychlorinated biphenyls.

    PubMed

    Choi, Yongju; Cho, Yeo-Myoung; Luthy, Richard G

    2013-07-02

    We report polyethylene (PE)-water partitioning coefficients (K(PE)) for 17 parent-polycyclic aromatic hydrocarbons (PAHs), 22 alkylated-PAHs, 3 perdeuterated parent-PAHs, and 100 polychlorinated biphenyl (PCB) congeners or coeluting congener groups. The K(PE) values for compounds in the same homologue group are within 0.2 log units for alkylated-PAHs but span up to an order of magnitude for PCBs, due to the greater contribution of the position of the substituents (i.e., chlorines for PCBs and alkyl groups for alkylated-PAHs) to the molecular structure. The K(PE) values in deionized water for parent- and alkylated-PAHs show a good correlation with a regression model employing the number of aromatic carbons (C(AR)) and aliphatic carbons (C(AL)) in each compound: log K(PE) = -0.241 + 0.313 C(AR) + 0.461 C(AL). The regression model is useful for the assessment of freely dissolved aqueous concentrations of alkylated-PAHs, which comprise a significant fraction of the total in petroleum-derived PAHs and in some pyrogenic PAH mixtures. For PCBs, experimentally determined octanol-water partitioning coefficients are the best predictor of the K(PE) values among the molecular parameters studied. The effect of salinity up to 20 or 30 parts per thousand is found to be relatively insignificant on K(PE) values for PAHs or PCBs, respectively.

  7. Natural and bioremediated selective degradation of polycyclic aromatic alkyl isomers in oil-contaminated soils

    SciTech Connect

    Sauer, T.C.; McCarthy, K.; Uhler, A.; Porta, A.

    1995-12-31

    In studies where 2- to 6-ring polycyclic aromatic hydrocarbons (PAHs) are determined as part of characterizing released oil constituents in environmental samples, the changes in composition of PAHs from weathering (e.g., evaporation, dissolution) and biodegradation are most often represented by PAH alkyl homologue distributions. Concentrations of PAH alkyl groups are the sum of individual PAH isomers of similar carbon number; such as for C2-naphthalenes, the C2 alkyl group consists of dimethyl and ethyl substitutions on the parent naphthalene. In weathering and degradation studies, the changes in relative concentration of the individual isomers within an alkyl group are rarely reported. In a field study of oiled soils, the authors looked at the selective losses, for a period of a year, of individual PAH alkyl isomers that occur both naturally by weathering processes and through the use of bioremediation technology. Results showed that decreases in alkyl group concentrations were not always represented by similar losses of each isomer in the alkyl group, but were often due to the preferential or selective loss of certain isomers in the group.

  8. Transducer influence of polycyclic aromatic hydrocarbons (PAHs) on photoisomerisation of 1-alkyl-2-(arylazo)imidazoles

    NASA Astrophysics Data System (ADS)

    Gayen, Pallab; Sinha, Chittaranjan

    2013-03-01

    The UV light irradiation to a solution of 1-alkyl-2-(arylazo)imidazole (L) in toluene shows transformation of trans to cis configuration about sbnd Ndbnd Nsbnd bond. The rate of photo-isomerisation and quantum yields are influenced by internal parameters like - nature of substituents, coordination to metal ions, steric and electronic effect, protonation etc. and the external factors like solvent (polarity, viscosity, dipole moment etc.), presence of innocent (to be chemically noninteracting) and noninnocent (chemically interacting) ions or molecules. In this work the influence of polycyclic aromatic hydrocarbons (PAH) such as - napththalene, anthracene, phenanthrene, pyrene - an innocent system, on the photochromic efficiency of L has been examined. The PAHs are π-donor and may form a π-π continuum with L which can significantly affect the motional (vibration, rotation) properties of the analyte and hence the photochromic activity. The rate and quantum yield of trans-to-cis isomerisation of L decrease with increasing [PAH] and also with increasing number of the fused phenyl ring(s) in PAH. Thus the photoisomerisation follows the rate sequence: no PAH > napththalene > anthracene-phenanthrene > pyrene. The reverse change, cis-to-trans is very slow upon light irradiation while appreciably fast in thermal process at dark. The activation energy (Ea) also decreases with [PAH] and number of fused phenyl rings.

  9. Evaluation of the phototoxicity of unsubstituted and alkylated polycyclic aromatic hydrocarbons to mysid shrimp (Americamysis bahia): Validation of predictive models.

    PubMed

    Finch, Bryson E; Marzooghi, Solmaz; Toro, Dominic M Di; Stubblefield, William A

    2017-01-06

    Crude oils are composed of an assortment of hydrocarbons, some of which are polycyclic aromatic hydrocarbons (PAHs). Polycyclic aromatic hydrocarbons are of particular interest due to their narcotic and potential phototoxic effects. Several studies have examined the phototoxicity of individual PAHs and fresh and weathered crude oils, and several models have been developed to predict PAH toxicity. Fingerprint analyses of oils have shown that PAHs in crude oils are predominantly alkylated. However, current models for estimating PAH phototoxicity assume toxic equivalence between unsubstituted (i.e., parent) and alkyl-substituted compounds. This approach may be incorrect if substantial differences in toxic potency exist between unsubstituted and substituted PAHs. The objective of the present study was to examine the narcotic and photo-enhanced toxicity of commercially available unsubstituted and alkylated PAHs to mysid shrimp (Americamysis bahia). Data were used to validate predictive models of phototoxicity based on the highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gap approach and to develop relative effect potencies. Results demonstrated that photo-enhanced toxicity increased with increasing methylation and that phototoxic PAH potencies vary significantly among unsubstituted compounds. Overall, predictive models based on the HOMO-LUMO gap were relatively accurate in predicting phototoxicity for unsubstituted PAHs but are limited to qualitative assessments. Environ Toxicol Chem 2017;9999:1-7. © 2017 SETAC.

  10. Parent, Alkylated, and Sulfur/Oxygen-Containing Polycyclic Aromatic Hydrocarbons in Mainstream Smoke from 13 Brands of Chinese Cigarettes.

    PubMed

    Gao, Bo; Du, Xueqing; Wang, Xinming; Tang, Jianhui; Ding, Xiang; Zhang, Yanli; Bi, Xinhui; Zhang, Gan

    2015-08-04

    China has the world's largest population of smokers with serious health consequences, yet we know a very limited spectrum of hazardous chemicals in cigarette smoke even for carcinogenic polycyclic aromatic hydrocarbons (PAHs). Here, we chose 13 popular cigarette brands sold in China markets, collected particulate matters in mainstream smoke using filter pads and an automatic smoking machine, and analyzed 56 PAHs, including 31 parent, 18 alkylated, and 7 sulfur/oxygen-containing PAHs (S/O PAHs). The 56 PAHs in mainstream smoke totaled from 244.2 ± 28.5 to 10254.8 ± 481.5 ng cig(-1); parent, alkylated, and S/O PAHs shared 16-23%, 64-74%, and 6-18%, respectively. Benzo[a]pyrene (BaP) ranged 1.1-41.6 ng cig(-1), while BaP equivalent concentrations (BaPeq) ranged 3.6-120.2 ng cig(-1), but contributions to BaPeq by individual carcinogenic PAH species varied with cigarette brands. When these cigarette smoke source profiles were pooled together with those of other combustion ones available in the literature, we found that widely used diagnostic ratios of parent PAHs failed to distinguish cigarette smoke from other combustion sources, except that the ratio indeno[1,2,3-cd]pyrene/(indeno[1,2,3-cd]pyrene + benzo[g,h,i]perylene) can largely separate cigarette smoke from vehicular emissions and that the ratio of Retene/(Retene + chrysene) can further discriminate cigarette smoke from coal combustion when alkylated PAHs are involved.

  11. Polycyclic aromatic hydrocarbons (PAHs) and alkylated PAHs in the coastal seawater, surface sediment and oyster from Dalian, Northeast China.

    PubMed

    Hong, Wen-Jun; Jia, Hongliang; Li, Yi-Fan; Sun, Yeqing; Liu, Xianjie; Wang, Luo

    2016-06-01

    A total of 46 polycyclic aromatic hydrocarbons (PAHs, 21 parent and 25 alkylated) were determined in seawater, surface sediment and oyster from coastal area of Dalian, North China. The concentration of Σ46PAHs in seawater, sediment, and oyster were 136-621 ng/L, 172-4700 ng/g dry weight (dw) and 60.0-129 ng/g wet weight (ww) in winter, and 65.0-1130 ng/L, 71.1-1090 ng/g dw and 72.8-216 ng/g ww in summer, respectively. High PAH levels were found in industrial area both in winter and summer. Selected PAH levels in sediments were compared with Sediments Quality Guidelines (ERM-ERL, TEL-PEL indexes) for evaluation probable toxic effects on marine organism and the results indicate that surface sediment from all sampling sites have a low to medium ecotoxicological risk. Daily intake of PAHs via oyster as seafood by humans were estimated and the results indicated that oyster intake would not pose a health risk to humans even 30 days after a oil spill accident near by. Water-sediment exchange analysis showed that, both in winter and summer, the fluxes for most high molecular weight PAHs were from seawater to sediment, while for low molecular weight PAHs, an equilibrium was reached between seawater and sediment. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Monthly variation and vertical distribution of parent and alkyl polycyclic aromatic hydrocarbons in estuarine water column: Role of suspended particulate matter.

    PubMed

    Wang, Xiaowei; Yuan, Ke; Chen, Baowei; Lin, Li; Huang, Bensheng; Luan, Tiangang

    2016-09-01

    The distribution and interaction of parent and alkyl polycyclic aromatic hydrocarbons (EPA-34 PAHs) among the multiple phases were investigated in estuarine water column of Humen outlet over a 12-months period. The water column was divided into 5 vertical layers, and each layer included dissolved phase, large- and small-size suspended particular matter (SPM). Regarding to EPA-34 PAHs, alkyl homologues were abundant, especially in the dissolved phase and small-size SPM. Moreover, SPM contributed a large proportion of EPA-34 PAHs in the water column especially for the large-size SPM, which therefore play an important role for the transportation of these pollutants. The EPA-34 PAHs concentrations in water column during wet season were higher than those in the dry season due to the decreasing of KD values which were affected by TSS and salinity obviously. Generally, the EPA-34 PAHs concentrations in the water column increased with the increasing of water depth, most of the highest concentrations of EPA-34 PAHs were found in the near-bottom layer due to the rapid sinking of large-size SPM and sediment resuspension. Additionally, during the ebb-flood tide period, the EPA-34 PAHs concentrations in different phases of the water column fluctuated oppositely based on the effects of hydrodynamic conditions.

  13. Measurement and modeling of activated carbon performance for the sequestration of parent- and alkylated-polycyclic aromatic hydrocarbons in petroleum-impacted sediments.

    PubMed

    Choi, Yongju; Cho, Yeo-Myoung; Gala, William R; Luthy, Richard G

    2013-01-15

    We present a first comprehensive set of experiments that demonstrate the performance of activated carbon (AC) to reduce the availability of polycyclic aromatic hydrocarbons (PAHs) including alkylated-PAHs in petroleum-impacted sediments. The uptake in polyethylene samplers for total PAHs in a well-mixed sediment slurry was reduced up to 99% and 98% for petroleum-impacted sediments with oil contents of 1% and 2%, respectively, by treatment with 5% AC. The AC showed similar efficiency for parent-PAHs and a suite of alkylated-PAHs, which predominate over parent-PAHs in petroleum-impacted sediments. A mass transfer model was used to simulate the AC performance in a slurry phase with site-specific mass transfer parameters determined in this study. Comparison between the experimental data and simulation results suggested that dissolved organic matter and/or oil phase may have attenuated the AC performance by a factor of 5-6 for 75-300 μm AC with 5% dose at one month. The attenuation in AC performance became negligible with increase in AC-sediment slurry contact time to 12 months and with decrease in AC particle size. The results show the potential for AC amendment to sequester PAHs in petroleum-impacted sediments and the effect of contact time and AC particle size on the efficiency of the treatment.

  14. Accurate analysis of polycyclic aromatic hydrocarbons (PAHs) and alkylated PAHs homologs in crude oil for improving the gas chromatography/mass spectrometry performance.

    PubMed

    Zhao, Yue; Hong, Bo; Fan, Yuqing; Wen, Mei; Han, Xue

    2014-02-01

    The common gas chromatography/mass spectrometry (GC/MS) approaches such as selective ion monitoring (SIM) or single ion extraction (SIE) from full scan data produce the error (over- or underestimation) estimates for the high level alkylated polycyclic aromatic hydrocarbons (PAHs). In order to rectify the error, the alkylated PAHs in the crude oil samples are quantified by deeply investigating the existing full scan data of 1D GC/MS, instead of resuming with the complex and inaccessible equipments (multidimensional gas chromatography or mass spectrometry). The aim of this study is to provide the detailed qualitative and quantitative basis data (confirming ions, relative abundance, retention indices, and area counts) of the high level alkylated PAHs by a comprehensive three-step method: (1) the potential confirming ions per isomer are selected by exploring the multiple fragment patterns formation mechanism; (2) the reasonable confirming ions are estimated by comparing extracted ion chromatography (EIC) of the potential confirming ions; (3) after deconvolution, composite chromatograms of the reasonable confirming ions illustrate the basis data by assigning peaks for target PAHs definitively. The validation data, resulting concentrations and diagnostic ratios for each homolog are compared with those obtained from SIM. The experimental data demonstrate that significant inaccurate identifications and concentration estimates are obtained when SIM mode is used for C4 Naphthalene (C4 N), C3 Phenanthrene (C3 P), C4 Phenanthrene (C4 P), C3 Dibenzothiophene (C3 D), C3 Fluorene (C3 F), C2-4 Chrysene (C2-4 C) and C1 Fluoranthene (C1 Flt). This study evaluates the usefulness of the previous fragmentation patterns, and confirms compound presence by GC/MS using the different spectral deconvolution software. This approach is developed as a broad screen for environmental samples (including petrol, diesel fuel and coal tar), with only the crude oil results being presented here.

  15. Bioassay of polycyclic aromatic hydrocarbons

    SciTech Connect

    Van Kirk, E.A.

    1980-08-01

    A positive relationship was found between the photodynamic activity of 24 polycyclic aromatic hydrocarbons versus published results on the mutagenicity, carcinogenicity, and initiation of unscheduled DNA synthesis. Metabolic activation of benzo(a)pyrene resulted in detection of increased mutagenesis in Paramecium tetraurelia as found also in the Ames Salmonella assay. The utility of P. tetraurelia as a biological detector of hazardous polycyclic aromatic hydrocarbons is discussed.

  16. Solid-phase microextraction measurement of parent and alkyl polycyclic aromatic hydrocarbons in milliliter sediment pore water samples and determination of K(DOC) values.

    PubMed

    Hawthorne, Steven B; Grabanski, Carol B; Miller, David J; Kreitinger, Joseph P

    2005-04-15

    The U.S. Environmental Protection Agency (EPA) narcosis model for benthic organisms in polycyclic aromatic hydrocarbon (PAH) contaminated sediments requires the measurement of 18 parent PAHs and 16 groups of alkyl PAHs ("34" PAHs) in pore water with desired detection limits as low as nanograms per liter. Solid-phase microextraction (SPME) with gas chromatographic/mass spectrometric (GC/ MS) analysis can achieve such detection limits in small water samples, which greatly reduces the quantity of sediment pore water that has to be collected, shipped, stored, and prepared for analysis. Four sediments that ranged from urban background levels (50 mg/kg total "34" PAHs) to highly contaminated (10 000 mg/kg total PAHs) were used to develop SPME methodology for the "34" PAH determinations with only 1.5 mL of pore water per analysis. Pore water was obtained by centrifuging the wet sediment, and alum flocculation was used to remove colloids. Quantitative calibration was simplified by adding 15 two- to six-ring perdeuterated PAHs as internal standards to the water calibration standards and the pore water samples. Response factors for SPME followed by GC/MS were measured for 22 alkyl PAHs compared to their parent PAHs and used to calibrate for the 18 groups of alkyl PAHs. Dissolved organic carbon (DOC) ranging from 4 to 27 mg/L had no measurable effect on the freely dissolved concentrations of two- and three-ring PAHs. In contrast, 5-80% of the total dissolved four- to six-ring PAHs were associated with the DOC rather than being freely dissolved, corresponding to DOC/water partitioning coefficients (K(DOC)) with log K(DOC) values ranging from 4.1 (for fluoranthene) to 5.6 (for benzo[ghi]perylene). However, DOC-associated versus freely dissolved PAHs had no significant effect on the total "34" PAH concentrations or the sum of the "toxic units" (calculated bythe EPA protocol), since virtually all (86-99%) of the dissolved PAH concentrations and toxic units were contributed by two

  17. Contorted polycyclic aromatics.

    PubMed

    Ball, Melissa; Zhong, Yu; Wu, Ying; Schenck, Christine; Ng, Fay; Steigerwald, Michael; Xiao, Shengxiong; Nuckolls, Colin

    2015-02-17

    CONSPECTUS: This Account describes a body of research in the design, synthesis, and assembly of molecular materials made from strained polycyclic aromatic molecules. The strain in the molecular subunits severely distorts the aromatic molecules away from planarity. We coined the term "contorted aromatics" to describe this class of molecules. Using these molecules, we demonstrate that the curved pi-surfaces are useful as subunits to make self-assembled electronic materials. We have created and continue to study two broad classes of these "contorted aromatics": discs and ribbons. The figure that accompanies this conspectus displays the three-dimensional surfaces of a selection of these "contorted aromatics". The disc-shaped contorted molecules have well-defined conformations that create concave pi-surfaces. When these disc-shaped molecules are substituted with hydrocarbon side chains, they self-assemble into columnar superstructures. Depending on the hydrocarbon substitution, they form either liquid crystalline films or macroscopic cables. In both cases, the columnar structures are photoconductive and form p-type, hole- transporting materials in field effect transistor devices. This columnar motif is robust, allowing us to form monolayers of these columns attached to the surface of dielectrics such as silicon oxide. We use ultrathin point contacts made from individual single-walled carbon nanotubes that are separated by a few nanometers to probe the electronic properties of short stacks of a few contorted discs. We find that these materials have high mobility and can sense electron-deficient aromatic molecules. The concave surfaces of these disc-shaped contorted molecules form ideal receptors for the molecular recognition and assembly with spherical molecules such as fullerenes. These interfaces resemble ball-and-socket joints, where the fullerene nests itself in the concave surface of the contorted disc. The tightness of the binding between the two partners can be

  18. Polycyclic Aromatic Hydrocarbons

    NASA Technical Reports Server (NTRS)

    Salama, Farid

    2010-01-01

    Carbonaceous materials play an important role in space. Polycyclic Aromatic Hydrocarbons (PAHs) are a ubiquitous component of the carbonaceous materials. PAHs are the best-known candidates to account for the IR emission bands. They are also thought to be among the carriers of the diffuse interstellar absorption bands (DIBs). 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 is to reproduce in the laboratory the physical conditions that exist in the emission and absorption interstellar zones. The harsh physical conditions of the ISM -low temperature, collisionless, strong UV radiation fields- are simulated in the laboratory by associating a molecular beam with an ionizing discharge to generate a cold plasma expansion. PAH ions and radicals are formed from the neutral precursors in an isolated environment at low temperature and probed with high-sensitivity cavity ringdown spectroscopy in the NUV-NIR range. Carbon nanoparticles are also formed during the short residence time of the precursors in the plasma and are characterized with time-offlight mass spectrometry. These experiments provide unique information on the spectra of large carbonaceous molecules and ions in the gas phase that can now be directly compared to interstellar and circumstellar observations (IR emission bands, DIBs, extinction curve). These findings also hold great potential for understanding the formation process of interstellar carbonaceous grains. We will review recent progress in the experimental and theoretical studies of PAHs, compare the laboratory data with astronomical observations and discuss the global implications.

  19. Nanostructured alkyl carboxylic acid-based restricted access solvents: Application to the combined microextraction and cleanup of polycyclic aromatic hydrocarbons in mosses.

    PubMed

    Caballero-Casero, N; Çabuk, H; Martínez-Sagarra, G; Devesa, J A; Rubio, S

    2015-08-26

    Alkyl carboxylic acid-based nanostructured solvents, synthesized in mixtures of tetrahydrofuran (THF) and water through self-assembly and coacervation, were proved to behave as restricted access liquids. Both physical and chemical mechanisms were found responsible for exclusion of macromolecules such as proteins and polysaccharides. The potential of these solvents for extracting small molecules from complex solid samples, without interference from large biomolecules, was here evaluated. For this purpose, they were applied to the extraction of 14 priority polycyclic aromatic hydrocarbons (PAHs) from mosses prior to their separation by liquid chromatography and fluorescence detection (LC-FLD). Sample treatment involved the vortex shaking of 200 mg of moss with 200 μL of decanoic acid-based solvent for 5 min, subsequent centrifugation for 8 min and analysis of the extract by LC-FLD using external calibration. Proteins precipitated during extraction because of both the decrease of the dielectric constant of the solution caused by THF and the formation of macromolecular complexes with decanoic acid. Polysaccharides were not solubilized in the aqueous cavities of the solvent because of their size exclusion. In-house method validation was performed according to the recommendations of the European Commission Decision 202/657/EC. Method detection and quantification limits for the different PAHs were in the ranges 0.04-0.24 and 0.14-0.80 μg kg(-1), respectively. The method was applied to the determination of different moss species collected in both polluted and unpolluted sites in the South of Spain. Recoveries were within the range 71-110%. The results obtained show that solvents with restricted access properties have the potential to expand the scope of application of restricted access materials to areas other than biological fluids because of their suitability to combine analyte isolation and sample cleanup of solid samples in a single step. Copyright © 2015 Elsevier B

  20. The retention and distribution of parent, alkylated, and N/O/S-containing polycyclic aromatic hydrocarbons on the epidermal tissue of mangrove seedlings.

    PubMed

    Li, Ruilong; Tan, Huadong; Zhu, Yaxian; Zhang, Yong

    2017-07-01

    The polycyclic aromatic hydrocarbons (PAHs) located on the epidermal tissues showed distinctive toxic effects to root, while the retention and distribution of PAHs on mangrove seedlings poorly understood. Our results confirmed that the partition coefficients (Kf) of the PAHs retained on the epidermal tissue of mangrove roots, such as Kandelia obovata, Avicennia marina and Aegiceras corniculatum, were much higher than the Poaceae plants roots, for example wheat and maize (Wild et al., 2005). Moreover, to the parent and alkyl PAHs, a well negative correlation was observed between the surface polarity of these three species of mangrove root and the Kf values (p < 0.05). To the N/O/S containing PAHs, these relationships were not obviously due to existing of the π-π, n-π interactions and hydrogen bonding between the N/O/S-containing PAHs and epidermal tissues. The PAHs retained on these three species of mangrove root epidermal tissues formed larger clusters than that of on Poaceae plants, such as wheat and maize (Wild et al., 2005) due to the limitation of the suberization of the root exodermis and endodermis. After exposure of 30 d, rhizo- and endophytic bacteria degraded parts of the N/O/S-containing PAHs to medium-lifetime fluorescence substances. To our knowledge, this is the first time to assess the retention of PAHs on the epidermal tissue of mangrove root, which will improve our understanding of the root uptake PAHs process. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Polycyclic aromatic hydrocarbons (PAHs) and their derivatives (alkyl-PAHs, oxygenated-PAHs, nitrated-PAHs and azaarenes) in urban road dusts from Xi'an, Central China.

    PubMed

    Wei, Chong; Bandowe, Benjamin A Musa; Han, Yongming; Cao, Junji; Zhan, Changlin; Wilcke, Wolfgang

    2015-09-01

    Urban road dusts are carriers of polycyclic aromatic compounds (PACs) and are therefore considered to be a major source of contamination of other environmental compartments and a source of exposure to PACs for urban populations. We determined the occurrence, composition pattern and sources of several PACs (29 alkyl- and parent-PAHs, 15 oxygenated-PAHs (OPAHs), 4 azaarenes (AZAs), and 11 nitrated-PAHs (NPAHs)) in twenty urban road dusts and six suburban surface soils (0-5cm) from Xi'an, central China. The average concentrations of ∑29PAHs, ∑4AZAs, ∑15OPAHs, and ∑11NPAHs were 15767, 673, 4754, and 885 n gg(-1) in road dusts and 2067, 784, 854, and 118 ng g(-1) in surface soils, respectively. The concentrations of most individual PACs were higher in street dusts than suburban soils, particularly for PACs with molecular weight>192 g mol(-1). The enrichment factors of individual PACs were significantly positively correlated with log KOA and log KOW, indicating an increasing deposition and co-sorption of the PACs in urban dusts with decreasing volatility and increasing hydrophobicity. Significant correlations between the concentrations of individual and sum of PACs, carbon fractions (soot and char), and source-characteristic PACs (combustion-derived PAHs and retene, etc.), indicated that PAHs, OPAHs and AZAs were mostly directly emitted from combustion activities and had similar post-emission fates, but NPAHs were possibly more intensely photolyzed after deposition as well as being emitted from vehicle exhaust sources. The incremental lifetime cancer risk (ILCR) resulting from exposure to urban dust bound-PACs was higher than 10(-6), indicating a non-negligible cancer risk to residents of Xi'an.

  2. THE PHOTOTOXICITY OF POLYCYCLIC AROMATIC HYDROCARBONS

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) continues to be interested in developing methods for the detection of polycyclic aromatic hydrocarbons (PAHS) in the environment. Polycyclic aromatic hydrocarbons (PAHS) are common contaminants in our environment. Being major product...

  3. THE PHOTOTOXICITY OF POLYCYCLIC AROMATIC HYDROCARBONS

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) continues to be interested in developing methods for the detection of polycyclic aromatic hydrocarbons (PAHS) in the environment. Polycyclic aromatic hydrocarbons (PAHS) are common contaminants in our environment. Being major product...

  4. Overview of Polycyclic Aromatic Compounds (PAC).

    PubMed

    Achten, Christine; Andersson, Jan T

    2015-03-15

    The chemical group of polycyclic aromatic compounds (PAC), including the better-known subgroup of polycyclic aromatic hydrocarbons (PAH) and the heterocyclic aromatic compounds (NSO-PAC, heterocycles), comprise several thousand individual compounds. It is hard to find a comprehensive overview in the literature of these PACs that includes a substantial amount of relevant properties. Here an attempt is made to summarize the most studied but also some less well-known PACs. In addition to basic data such as recommended names, abbreviations, CAS numbers, molecular formulas, chemical structures, and exact mono-isotopic molecular weights, physico-chemical properties taken from the literature like boiling points, vapor pressures, water solubilities, Henry's Law constants, n-octanol-water partition coefficients (log KOW), and pKa are summarized. Selected toxicological data are listed indicating carcinogenic and mutagenic activity or effects on different organisms. PAC nomenclature is a complex topic, so suggestions for practical use are made. Regarding available data, estimated (instead of measured) values should be used with caution because considerable deviations from experimentally determined values can occur. For an enhanced understanding of the behavior of single PACs in comparison with each other, some of the properties mentioned above are plotted vs. the number of rings or the degree of alkylation. Also, some physico-chemical data are correlated with different functional groups as substituents of the PAHs. This article reveals that rather little is known about the less common PACs, e.g., higher molecular weight compounds, alkylated or otherwise substituted aromatics, for instance, keto-, oxo-, amino-, nitro-, cyano-PAHs, or some heterocyclic aromatic compounds, including their derivatives. It mirrors the limited state of knowledge about the variety of PACs that do not belong to the 16 EPA PAHs.

  5. Overview of Polycyclic Aromatic Compounds (PAC)

    PubMed Central

    Achten, Christine; Andersson, Jan T.

    2015-01-01

    The chemical group of polycyclic aromatic compounds (PAC), including the better-known subgroup of polycyclic aromatic hydrocarbons (PAH) and the heterocyclic aromatic compounds (NSO-PAC, heterocycles), comprise several thousand individual compounds. It is hard to find a comprehensive overview in the literature of these PACs that includes a substantial amount of relevant properties. Here an attempt is made to summarize the most studied but also some less well-known PACs. In addition to basic data such as recommended names, abbreviations, CAS numbers, molecular formulas, chemical structures, and exact mono-isotopic molecular weights, physico-chemical properties taken from the literature like boiling points, vapor pressures, water solubilities, Henry's Law constants, n-octanol-water partition coefficients (log KOW), and pKa are summarized. Selected toxicological data are listed indicating carcinogenic and mutagenic activity or effects on different organisms. PAC nomenclature is a complex topic, so suggestions for practical use are made. Regarding available data, estimated (instead of measured) values should be used with caution because considerable deviations from experimentally determined values can occur. For an enhanced understanding of the behavior of single PACs in comparison with each other, some of the properties mentioned above are plotted vs. the number of rings or the degree of alkylation. Also, some physico-chemical data are correlated with different functional groups as substituents of the PAHs. This article reveals that rather little is known about the less common PACs, e.g., higher molecular weight compounds, alkylated or otherwise substituted aromatics, for instance, keto-, oxo-, amino-, nitro-, cyano-PAHs, or some heterocyclic aromatic compounds, including their derivatives. It mirrors the limited state of knowledge about the variety of PACs that do not belong to the 16 EPA PAHs. PMID:26823644

  6. Hemimicelles of alkyl carboxylates chemisorbed onto magnetic nanoparticles: study and application to the extraction of carcinogenic polycyclic aromatic hydrocarbons in environmental water samples.

    PubMed

    Ballesteros-Gómez, Ana; Rubio, Soledad

    2009-11-01

    In this work, magnetic nanoparticles (MNPs) coated with hemimicelles of alkyl (C(10)-C(18)) carboxylates, which have traditionally been used to prepare ferrofluids for technological applications, were used for the first time to extract organic contaminants from environmental water samples. The nanoparticles were coated by following a simple, rapid procedure (30 min at 85 degrees C) that uses commercially available magnetite of 20-30 nm mean particle diameter. The strong chemical bonding between the surfactant and magnetite relative to the electrostatic forces involved in conventional hemimicelle-based sorbents precludes leaching of the surfactant and facilitates its reuse and the obtainment of surfactant-free extracts. Tetradecanoate hemimicelles were used here to extract carcinogenic polycyclic aromatic hydrocarbons (CPAHs) prior to analysis by liquid chromatography (using a C(18) Supelcosil LC-PAH column and a gradient elution program with water and acetonitrile) and fluorescence detection. The procedure involved stirring filtered aqueous samples (350 mL) with 200 mg of tetradecanoate-coated MNPs for 15 min, isolating the sorbent with a Nd-Fe-B magnet and eluting the CPAHs with a mixture of acetonitrile and tetrahydrofuran. The extraction efficiency was not influenced by salt concentrations up to 1 M and pH values over the range 2.5-9. The preconcentration factor was 116. No cleanup of the extracts was needed, and the method proved matrix-independent. The limits of quantitation thus obtained, 0.2-0.5 ng L(-1), meet the stringent water quality requirements established by the recently amended European Water Framework Directive 2000/60/EC and also the U.S. EPA for the determination of CPAHs in surface and ground waters. The proposed method was successfully applied to the determination of these pollutants in surface and ground environmental water samples collected from various places in southern Spain. Recoveries from samples spiked with CPAHs at concentrations of 1

  7. Alkylation of organic aromatic compounds

    DOEpatents

    Smith, Jr., Lawrence A.; Arganbright, Robert P.; Hearn, Dennis

    1993-01-01

    Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C.sub.2 to C.sub.10 olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80.degree. C. to 500.degree. C., using as the catalyst a mole sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene to about the mid point of the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms.

  8. Alkylation of organic aromatic compounds

    DOEpatents

    Smith, L.A. Jr.; Arganbright, R.P.; Hearn, D.

    1994-06-14

    Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C[sub 2] to C[sub 10] olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80 C to 500 C, using as the catalyst a molecular sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene below the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms. 1 fig.

  9. Alkylation of organic aromatic compounds

    DOEpatents

    Smith, L.A. Jr.; Arganbright, R.P.; Hearn, D.

    1993-09-07

    Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C[sub 2] to C[sub 10] olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80 C to 500 C, using as the catalyst a molecular sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene to about the mid point of the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms. 1 figures.

  10. Alkylation of organic aromatic compounds

    DOEpatents

    Smith, Jr., Lawrence A.

    1989-01-01

    Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C.sub.2 to C.sub.10 olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80.degree. C. to 500.degree. C., using as the catalyst a mole sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene below the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms.

  11. Alkylation of organic aromatic compounds

    DOEpatents

    Smith, L.A. Jr.

    1989-07-18

    Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C[sub 2] to C[sub 10] olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80 C to 500 C, using as the catalyst a mole sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene below the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms. 1 fig.

  12. Alkylation of organic aromatic compounds

    DOEpatents

    Smith, Jr., Lawrence A.; Arganbright, Robert P.; Hearn, Dennis

    1994-01-01

    Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C.sub.2 to C.sub.10 olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80.degree. C. to 500.degree. C., using as the catalyst a mole sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene below the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms.

  13. Alkylation of organic aromatic compounds

    DOEpatents

    Smith, L.A. Jr.; Arganbright, R.P.; Hearn, D.

    1993-01-05

    Aromatic compounds are alkylated in a combination reactor/distillation column comprising a vessel suitable for operating between 70 C and 500 C and from 0.5 to 20 atmospheres pressure; an inert distillation packing in the lower one-third of said vessel; solid acidic catalytic material such as zeolites or an acidic cation exchange resin supported in the middle one-third of said vessel; and inert distillation packing in the upper one-third of said vessel. A benzene inlet is located near the upper end of the vessel; an olefin inlet is juxtaposed with said solid acidic catalytic material; a bottoms outlet is positioned near the bottom of said vessel for removing said cumene and ethyl benzene; and an overhead outlet is placed at the top of said vessel for removing any unreacted benzene and olefin.

  14. Alkylation of organic aromatic compounds

    DOEpatents

    Smith, Jr., Lawrence A.; Arganbright, Robert P.; Hearn, Dennis

    1993-01-01

    Aromatic compounds are alkylated in a combination reactor/distillation column comprising a vessel suitable for operating between 70.degree. C. and 500.degree. C. and from 0.5 to 20 atmospheres pressure; an inert distillation packing in the lower one-third of said vessel; solid acidic catalytic material such as zeolites or an acidic cation exchange resin supported in the middle one-third of said vessel; and inert distillation packing in the upper one-third of said vessel. A benzene inlet is located near the upper end of the vessel; an olefin inlet is juxtaposed with said solid acidic catalytic material; a bottoms outlet is positioned near the bottom of said vessel for removing said cumene and ethyl benzene; and an overhead outlet is placed at the top of said vessel for removing any unreacted benzene and olefin.

  15. Polycyclic aromatic hydrocarbons in carcinogenesis.

    PubMed Central

    Warshawsky, D

    1999-01-01

    A symposium on "Polycyclic Aromatic Hydrocarbons (PAHs) in Carcinogenesis" was presented at the third International Congress of Pathophysiology held in Lathi, Finland, 28 June-3 July 1998. The congress was also sponsored by the International Union of Biological Sciences and the International Society of Free Radical Research. Institutional support for the symposium included the Electric Power Research Institute, National Center for Toxicological Research, and EPA/National Health and Environmental Effects Research Laboratory and the Office of Solid Waste and Emergency Response. The symposium focused on the sources, carcinogenicity, genotoxicity, and risk assessment of individual and mixtures of PAHs that are found in solid wastes, Superfund sites, and other hazardous waste sites. Based on the occurrence of PAHs at numerous Superfund sites and the significant data gaps on the toxic potential of certain PAHs, the information developed during this symposium would be of value in assessing health risks of these chemicals at Superfund and other hazardous waste sites. PMID:10090712

  16. Development and application of a simultaneous SPE-method for polycyclic aromatic hydrocarbons (PAHs), alkylated PAHs, heterocyclic PAHs (NSO-HET) and phenols in aqueous samples from German Rivers and the North Sea.

    PubMed

    Siemers, Anne-Kathrin; Mänz, Jan Sebastian; Palm, Wolf-Ulrich; Ruck, Wolfgang K L

    2015-03-01

    Polycyclic aromatic hydrocarbons (PAHs), heterocyclic PAHs (NSO-HETs), alkylated PAHs and phenols are known as the prevailing contaminants in groundwater at tar contaminated sites. Besides these local sources, the concentrations and the distribution in particular of NSO-HETs in environmental samples, such as rivers, have received notably less attention. To investigate their occurrence in river basins two sensitive analytical methods for the simultaneous extraction of 86 substances including NSO-HETs, classical EPA-PAHs, alkylated PAHs and phenols were developed: liquid-liquid extraction for the whole water phase and solid phase extraction for the dissolved water phase only. Solely GC-MS or additionally LC-MSMS for fractionated basic nitrogen heterocycles (N-HETs) were used for quantification. Limits of quantification were in the low ngL(-1) range. Concentrations were determined in 29 aqueous samples from 8 relatively large rivers located in Lower Saxony (Germany) and the North Sea. NSO-HETs had comparable or even higher sum concentrations than EPA-PAHs. N-HETs, especially acridine and quinolines with concentrations of up to 20ngL(-1) per substance, were predominant.

  17. Polycyclic Aromatic Hydrocarbons (PAHs) produced in the combustion of fatty acid alkyl esters from different feedstocks: Quantification, statistical analysis and mechanisms of formation.

    PubMed

    Llamas, Alberto; Al-Lal, Ana-María; García-Martínez, María-Jesús; Ortega, Marcelo F; Llamas, Juan F; Lapuerta, Magín; Canoira, Laureano

    2017-05-15

    Polycyclic Aromatic Hydrocarbons (PAHs) are pollutants of concern due to their carcinogenic and mutagenic activity. Their emissions are mainly related with the combustion or pyrolysis of the organic matter, such as in fossil fuels combustion. It is important to characterize PAHs in the combustions of biofuels due to their increasing importance in the actual energetic setting. There is a lot of research focused in PAHs emission due to the combustion in diesel engines; but only few of them have analyzed the effect of raw material and type of alcohol used in the transesterification process. Different raw materials (i.e. animal fat, palm, rapeseed, linseed, peanut, coconut, and soybean oils) have been used for obtaining FAME and FAEE. A method for measuring PAHs generated during combustion in a bomb calorimeter has been developed. Combustion was made at different oxygen pressures and the samples were taken from the bomb after each combustion. Samples were extracted and the PAHs amounts formed during combustion were analyzed by GC-MS. This research shows the statistical relationships among the 16 PAHs of concern, biodiesel composition and oxygen pressure during combustion.

  18. Birds and polycyclic aromatic hydrocarbons

    USGS Publications Warehouse

    Albers, P.H.

    2006-01-01

    Polycyclic aromatic hydrocarbons (PAH) are present throughout the global environment and are produced naturally and by activities of humans. Effects of PAH on birds have been determined by studies employing egg injection, egg immersion, egg shell application, single and multiple oral doses, subcutaneous injection, and chemical analysis of field-collected eggs and tissue. The four-to six-ring aromatic compounds are the most toxic to embryos, young birds, and adult birds. For embryos, effects include death, developmental abnormalities, and a variety of cellular and biochemical responses. For adult and young birds, effects include reduced egg production and hatching, increased clutch or brood abandonment, reduced growth, increased organweights, and a variety of biochemical responses. Trophic level accumulation is unlikely. Environmental exposure to PAH in areas of high human population or habitats affected by recent petroleum spills might be sufficient to adversely affect reproduction. Evidence of long-term effects of elevated concentrations of environmental PAH on bird populations is very limited and the mechanisms of effect are unclear.

  19. Infrared Spectra of Polycyclic Aromatic Hydrocarbons (PAHs)

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles W., Jr.; Bakes, E. L. O.

    2000-01-01

    We have computed the synthetic infrared spectra of some polycyclic aromatic hydrocarbons containing up to 54 carbon atoms. The species studied include ovalene, circumcoronene, dicoronylene, and hexabenzocoronene. We report spectra for anions, neutrals, cations, and multiply charged cations.

  20. Determination of polycyclic aromatic hydrocarbons, dibenzothiophene, and alkylated homologs in the lichen Hypogymnia physodes by gas chromatography using single quadrupole mass spectrometry and time-of-flight mass spectrometry.

    PubMed

    Studabaker, William B; Puckett, Keith J; Percy, Kevin E; Landis, Matthew S

    2017-04-07

    Development of the Athabasca Oil Sands Region in northeastern Alberta, Canada has contributed polycyclic aromatic hydrocarbons (PAHs) and polycyclic aromatic compounds (PACs), which include alkyl PAHs and dibenzothiophenes, to the regional environment. A new analytical method was developed for quantification of PAHs and PACs in the epiphytic lichen bioindicator species Hypogymnia physodes for use in the development of receptor models for attribution of PAH and PAC concentrations to anthropogenic and natural emission sources. Milled lichens were extracted with cyclohexane, and extracts were cleaned on silica gel using automated solid phase extraction techniques. Quantitative analysis was performed by gas chromatography with selected ion monitoring (GC-SIM-MS) for PAHs, and by GC with time-of-flight mass spectrometry (GC-TOF-MS) for PACs. PACs were quantitated in groups using representative reference compounds as calibration standards. Analytical detection limits were ≤2.5ngg(-1) for all individual compounds. Precision as measured by laboratory duplicates was variable; for individual analytes above 5ngg(-1) the mean absolute difference between duplicates was typically <20%. Selection of single-analyte markers for source attribution should include consideration of data quality indicators. Use of TOF-MS to spectrally characterize PAC group constituents identified significant challenges for the accurate quantitation of PACs with more than two carbons in their side chain(s). Total PAH concentrations in lichen samples ranged from 12 to 482ngg(-1). Total PACs in each sample varied from a fraction of total PAHs to more than four times total PAHs. Results of our analyses of H. physodes are compared with other studies using other species of lichens as PAH receptors and with passive monitoring data using polyurethane foam (PUF) samplers in the Athabasca Oil Sands Region (AOSR). This study presents the first analytical methodology developed for the determination of PACs in an

  1. PROTONATED POLYCYCLIC AROMATIC HYDROCARBONS REVISITED

    SciTech Connect

    Ricca, Alessandra; Bauschlicher, Charles W. Jr; Allamandola, Louis J. E-mail: Charles.W.Bauschlicher@nasa.gov

    2011-02-01

    We reconsider the contribution that singly protonated polycyclic aromatic hydrocarbons (PAHs; HPAH{sup +}s) might make to the Class A component of the 6.2 {mu}m interstellar emission feature in light of the recent experimental measurements of protonated naphthalene and coronene. Our calculations on the small HPAH{sup +}s have a band near 6.2 {mu}m, as found in experiment. While the larger HPAH{sup +}s still have emission near 6.2 {mu}m, the much larger intensity of the band near 6.3 {mu}m overwhelms the weaker band at 6.2 {mu}m, so that the 6.2 {mu}m band is barely visible. Since the large PAHs are more representative of those in the interstellar medium, our work suggests that large HPAH{sup +}s cannot be major contributors to the observed emission at 6.2 {mu}m (i.e., Class A species). Saturating large PAH cations with hydrogen atoms retains the 6.2 {mu}m Class A band position, but the rest of the spectrum is inconsistent with observed spectra.

  2. Polycyclic Aromatic Hydrocarbons with SPICA

    NASA Astrophysics Data System (ADS)

    Berné, O.; Joblin, C.; Mulas, G.; Tielens, A. G. G. M.; Goicoechea, J. R.

    2009-12-01

    Thanks to high sensitivity, high angular resolution and broad spectral coverage, SPICA will offer a unique opportunity to better characterize the nature of polycyclic aromatic hydrocarbons (PAHs) and very small grains (VSGs), to better use them as probes of astrophysical environments. The angular resolution will enable to probe the chemical frontiers in the evolution process from VSGs to neutral PAHs, to ionized PAHs and to "Grand-PAHs" in photodissotiation regions and HII regions, as a function of G0 /n (UV radiation field / density). High sensitivity will favor the detection of the far-IR skeletal emission bands of PAHs, which provide specific fingerprints and could lead to the identification of individual PAHs. This overall characterization will allow to use PAH and VSG populations as tracers of physical conditions in spatially resolved protoplanetary disks and nearby galaxies (using mid-IR instruments), and in high redshift galaxies (using the far-IR instrument), thanks to the broad spectral coverage SPICA provides. Based on our previous experience with ISO and Spitzer we discuss how these goals can be reached.

  3. A phosphine-mediated reaction of cyclic 1,2-diones and 3-alkyl allenoates: an efficient protocol for benzannulation applicable to the synthesis of polycyclic aromatic hydrocarbons.

    PubMed

    Jose, Anu; A J, Jayakrishnan; Vedhanarayanan, Balaraman; Menon, Rajeev S; Varughese, Sunil; Suresh, Eringathodi; Nair, Vijay

    2014-05-07

    A facile one-pot benzannulation strategy involving phosphine-3-alkyl allenoate zwitterions and cyclic 1,2-diones is described. The strategy is effectively utilized in the synthesis of fluoranthenes and benzo[a]aceanthrylenes with impressive photophysical properties. This is the first report on an intermolecular benzannulation using a 3-alkyl allenoate as a four carbon synthon.

  4. Pressurized liquid extraction using water/isopropanol coupled with solid-phase extraction cleanup for semivolatile organic compounds, polycyclic aromatic hydrocarbons (PAH), and alkylated PAH homolog groups in sediment

    USGS Publications Warehouse

    Burkhardt, M.R.; Zaugg, S.D.; Burbank, T.L.; Olson, M.C.; Iverson, J.L.

    2005-01-01

    Polycyclic aromatic hydrocarbons (PAH) are recognized as environmentally relevant for their potential adverse effects on human and ecosystem health. This paper describes a method to determine the distribution of PAH and alkylated homolog groups in sediment samples. Pressurized liquid extraction (PLE), coupled with solid-phase extraction (SPE) cleanup, was developed to decrease sample preparation time, to reduce solvent consumption, and to minimize background interferences for full-scan GC-MS analysis. Recoveries from spiked Ottawa sand, environmental stream sediment, and commercially available topsoil, fortified at 1.5-15 ??g per compound, averaged 94.6 ?? 7.8%, 90.7 ?? 5.8% and 92.8 ?? 12.8%, respectively. Initial method detection limits for single-component compounds ranged from 20 to 302 ??g/kg, based on 25 g samples. Results from 28 environmental sediment samples, excluding homologs, show 35 of 41 compounds (85.4%) were detected in at least one sample with concentrations ranging from 20 to 100,000 ??g/kg. The most frequently detected compound, 2,6-dimethylnaphthalene, was detected in 23 of the 28 (82%) environmental samples with a concentration ranging from 15 to 907 ??g/kg. The results from the 28 environmental sediment samples for the homolog series showed that 27 of 28 (96%) samples had at least one homolog series present at concentrations ranging from 20 to 89,000 ??g/kg. The most frequently detected homolog series, C2-alkylated naphthalene, was detected in 26 of the 28 (93%) environmental samples with a concentration ranging from 25 to 3900 ??g/kg. Results for a standard reference material using dichloromethane Soxhlet-based extraction also are compared. ?? 2005 Elsevier B.V. All rights reserved.

  5. Dihydrodiol dehydrogenase and polycyclic aromatic hydrocarbon metabolism

    SciTech Connect

    Smithgall, T.E.

    1986-01-01

    Carcinogenic activation of polycyclic aromatic hydrocarbons by microsomal monoxygenases proceeds through trans-dihydrodiol metabolites to diol-epoxide ultimate carcinogens. This thesis directly investigated the role of dihydrodiol dehydrogenase, a cytosolic NAD(P)-linked oxidoreductase, in the detoxification of polycyclic aromatic trans-dihydrodiols. A wide variety of non-K-region trans-dihydrodiols were synthesized and shown to be substrates for the homogeneous rat liver dehydrogenase, including several potent proximate carcinogens derived from 7,12-dimethylbenz(a)anthracene, 5-methylchrysene, and benzo(a)pyrene. Since microsomal activation of polycyclic aromatic hydrocarbons is highly stereospecific, the stereochemical course of enzymatic trans-dihydrodiol oxidation was monitored using circular dichroism spectropolarimetry. The major product formed from the dehydrogenase-catalyzed oxidation of the trans-1,2-dihydrodiol of naphthalene was characterized using UV, IR, NMR, and mass spectroscopy, and appears to be 4-hydroxy-1,2-naphthoquinone. Mass spectral analysis suggests that an analogous hydroxylated o-quinone is formed as the major product of benzo(a)pyrene-7,8-dihydrodiol oxidation. Enzymatic oxidation of trans-dihydrodiols was shown to be potently inhibited by all of the major classes of the nonsteroidal antiinflammatory drugs. Enhancement of trans-dihydrodiol proximate carcinogen oxidation may protect against possible adverse effects of the aspirin-like drugs, and help maintain the balance between activation and detoxification of polycyclic aromatic hydrocarbons.

  6. Polycyclic Aromatic Triptycenes: Oxygen Substitution Cyclization Strategies

    PubMed Central

    VanVeller, Brett; Schipper, Derek J.; Swager, Timothy M.

    2012-01-01

    The cyclization and planarization of polycyclic aromatic hydrocarbons with concomitant oxygen substitution was achieved through acid catalyzed transetherification and oxygen-radical reactions. The triptycene scaffold enforces proximity of the alcohol and arene reacting partners and confers significant rigidity to the resulting π system, expanding the tool set of iptycenes for materials applications. PMID:22510100

  7. Monitoring of vapor phase polycyclic aromatic hydrocarbons

    DOEpatents

    Vo-Dinh, Tuan; Hajaligol, Mohammad R.

    2004-06-01

    An apparatus for monitoring vapor phase polycyclic aromatic hydrocarbons in a high-temperature environment has an excitation source producing electromagnetic radiation, an optical path having an optical probe optically communicating the electromagnetic radiation received at a proximal end to a distal end, a spectrometer or polychromator, a detector, and a positioner coupled to the first optical path. The positioner can slidably move the distal end of the optical probe to maintain the distal end position with respect to an area of a material undergoing combustion. The emitted wavelength can be directed to a detector in a single optical probe 180.degree. backscattered configuration, in a dual optical probe 180.degree. backscattered configuration or in a dual optical probe 90.degree. side scattered configuration. The apparatus can be used to monitor an emitted wavelength of energy from a polycyclic aromatic hydrocarbon as it fluoresces in a high temperature environment.

  8. Polycyclic aromatic hydrocarbons in smoke particles from wood and duff burning

    NASA Astrophysics Data System (ADS)

    Tan, Yulin L.; Quanci, John F.; Borys, Randolf D.; Quanci, Martin J.

    Smoke particles from wood burning and duff burning were analysed for polycyclic aromatic hydrocarbons (PAH) by gas chromatography/mass spectrometry. PAH composition in smoke particles from wood burning was found to resemble those from other environmental samples, such as air particles and sediments where parental PAH are the predominant species. A catalytic combustor retrofitted on the wood-burning stove reduced the PAH concentrations significantly. The reduction was more pronounced for parental PAH than their alkylated homologs. Probably, the molecular configuration affects the catalytic efficiency. Smoke particles from duff burning contained a strikingly different PAH composition, with phenanthrene, alkylated phenanthrenes, alkylated cycolopenta( def)phenanthrene and dodecahydrochrysene as the predominant species.

  9. Characterization and analysis of polycyclic aromatic hydrocarbons

    SciTech Connect

    Breuer, G.M.; Smith, J.P.

    1984-01-01

    Sampling and analytical procedures were developed for determining the concentrations of polycyclic aromatic hydrocarbons in animal-exposure chambers during studies on exposure to diesel exhaust, coal dust, or mixtures of these two pollutants. Fluoranthene, pyrene, benzo(a)anthracene, chrysene, benzo(e)pyrene, benzo(k)fluoranthene, and benzo(a)pyrene were used as representative polycyclic aromatic hydrocarbons. High-pressure liquid chromatography with fluorescence detection was used for analysis. Coal-dust only samples revealed a broad, rising background in the chromatogram with small peaks superimposed corresponding to fluoranthene, pyrene, and benzo(a)anthracene, diesel exhaust only samples showed many peaks on a flat baseline including those corresponding to fluoranthene, pyrene, benzo(a)anthracene, benzo(k)fluoranthene, and benzo(a)pyrene. In general, no polynuclear aromatics were noted in the clean air samples. The authors note that relatively minor changes in air/fuel ratio, lubricant, fuel, and load may have substantial effects on very minor components of the exhaust emission.

  10. Cyclophanes containing large polycyclic aromatic hydrocarbons.

    PubMed

    Ghasemabadi, Parisa Ghods; Yao, Tieguang; Bodwell, Graham J

    2015-09-21

    Cyclophanes have been firmly entrenched as a distinct class of compounds for well over half a century. The two main factors that have kept this field of chemistry going so strongly for such a long time are tremendous structural diversity and the interesting behaviour that is often observed. Although a very large number cyclophanes has been reported, only a very small proportion of them contain polycyclic aromatic systems that can be thought of as "large", i.e. with ≥4 rings. This Review puts the spotlight on such cyclophanes, illuminating both the chemistry that was used to synthesize them and what was learned from studying them. Context for the main body is provided by the careful consideration of the anatomy of a cyclophane and the classification of general synthetic approaches. The subsequent sections cover eleven different PAHs and are organized primarily according to increasing size of the aromatic system, starting with pyrene (C16, the only large polycyclic aromatic system to have been incorporated into numerous cyclophanes) and ending with hexabenzo[bc,ef,hi,kl,no,qr]coronene (C42).

  11. Application of biotechnology for the biodegradation of polycyclic aromatic hydrocarbons

    SciTech Connect

    Cerniglia, C.E. )

    1989-01-01

    Polycyclic aromatic hydrocarbons (PAHs) and their alkyl and nitrated analogs are widely distributed in sediments and aquatic environments. Many PAHs have been shown to exhibit a large variety of biological activities. The goal of this research program are: 1. To isolate microorganisms from PAH-contaminated sediments which have the ability to metabolize and detoxify PAHs. 2. To determine the relationship between PAH structure and mineralization rates. 3. To determine whether differences in the physical, chemical and microbial characteristics of ecosystems predictably affect the disposition and persistence of PAHs in the environment. 4. To use multicomponent microcosms containing sediment and waste collected from chemically contaminated sites to determine the rate and extent of degradation of PAHs. Results of these studies in the biodegradation of PAHs will be presented.

  12. Alkyl Azides, Diazides, Haloazides and Bridged Polycyclic Diazides

    DTIC Science & Technology

    1991-05-16

    temperature. Most of the methyl ether was removed during this process. The ehtyl ether was distilled from the reaction mixture using a water aspirator into a...Street PROGRAM IPROJECT ITASK IWORK li1111? ArliiqIoh, VA 22217-5000 EILIMENT NO I NO. I oACCESSION P10) Alkyl Azides, Dlazides, laloazides and...REPRODUCE LEGIBLY. ALKYL AZIDES, DIAZIDES, HALOAZIDES AND BRIDGED POLYCYCLIC DIAZIDES Final REPORTe July 1, 1989-November 14, 1990 A6jd.%4gi0 F’or

  13. Petroleum and individual polycyclic aromatic hydrocarbons

    USGS Publications Warehouse

    Albers, Peter H.; Hoffman, David J.; Rattner, Barnett A.; Burton, G. Allen; Cairns, John

    1995-01-01

    Crude petroleum, refined-petroleum products, and individual polycyclic aromatic hydrocarbons (PAHs) contained within petroleum are found throughout the world. their presence has been detected in living and nonliving components of ecosystems. Petroleum can be an environmental hazard for wild animals and plants. Individual PAHs are also hazardous to wildlife, but they are most commonly associated with human illnesses. Because petroleum is a major environmental source of these PAHs, petroleum and PAHs are jointly presented in this chapter. Composition, sources, environmental fate, and toxic effects on all living components of aquatic and terrestrial environments are addessed.

  14. Bioremediation technologies for polycyclic aromatic hydrocarbon compounds

    SciTech Connect

    Alleman, B.C.; Leeson, A.

    1999-11-01

    Polycyclic aromatic hydrocarbon compounds (PAHs) are common and challenging contaminants that affect soil and sediments. Methods for treating PAHs have undergone change and refinement in the recent past, and this volume presents the latest trends in PAH remediation theory and practice. The papers in this volume cover topics ranging from the remediation of manufactured gas plant (MGP) sites to the remediation of sediments. The papers present lab and field studies, characterization studies, comparison studies, and descriptions of technologies ranging from composting to thermally enhanced bioremediation to fungal technologies and other innovative approaches.

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

    PubMed

    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 <20% for all analytes. The results obtained demonstrate that acenaphthene, fluorantene, phenanthrene, anthracene, fluoranthene and pyrene were found in all samples with a similar distribution, but different content when yogurts with low and high fats were compared.

  16. Interstellar Polycyclic Aromatic Compounds and Astrophysics

    NASA Technical Reports Server (NTRS)

    Hudgins, Douglas M.; DeVincenzi, Donald (Technical Monitor)

    2001-01-01

    Over the past fifteen years, thanks to significant, parallel advancements in observational, experimental, and theoretical techniques, tremendous strides have been made in our understanding of the role polycyclic aromatic compounds (PAC) in the interstellar medium (ISM). Twenty years ago, the notion of an abundant population of large, carbon rich molecules in the ISM was considered preposterous. Today, the unmistakable spectroscopic signatures of PAC - shockingly large molecules by previous interstellar chemistry standards - are recognized throughout the Universe. In this paper, we will examine the interstellar PAC model and its importance to astrophysics, including: (1) the evidence which led to inception of the model; (2) the ensuing laboratory and theoretical studies of the fundamental spectroscopic properties of PAC by which the model has been refined and extended; and (3) a few examples of how the model is being exploited to derive insight into the nature of the interstellar PAC population.

  17. Polycyclic aromatic hydrocarbons and cancer in man

    SciTech Connect

    Mastrangelo, G.; Marzia, V.; Fadda, E.

    1996-11-01

    Various substances and industrial processes, surrogates of exposure to polycyclic aromatic hydrocarbons (PAHs), are currently classified as human carcinogens. This paper reviews recent epidemiological studies reporting direct evidence of the carcinogenic effects of PAHs in occupationally exposed subjects. Risks of lung and bladder cancer were dose dependent when PAHs were measured quantitatively and truly nonexposed groups were chosen for comparison. These new findings suggest that the current threshold limit value of 0.2 mg/m{sup 3} of benzene soluble matter (which indicates PAH exposure) is unacceptable because, after 40 years of exposure, it involves a relative risk of 1.2-1.4 for lung cancer and 2.2 for bladder cancer. 33 refs., 2 tabs.

  18. Polycyclic Aromatic Hydrocarbons (by Ronald G. Harvey)

    NASA Astrophysics Data System (ADS)

    Murray, C. F.

    1998-11-01

    Ronald G. Harvey. Wiley, VCH: New York, 1997. 667 pp. ISBN 0-471-18608-2. $125. This text is a timely and welcome addition to the ever-growing literature on polycyclic aromatic hydrocarbon (PAH) chemistry and an essential addition to the chemist's library. It is the most comprehensive and complete account of the synthesis and chemical properties of polyarenes to date. The author has brought together, in one volume, detailed information on the physical and spectral properties, synthetic methods, chemical reactions, and molecular structures of a broad range of polyarenes, both alternant and nonalternant, and their substituted derivatives. (A total of 358 ring structures are covered, 233 of which are nonalternant PAH compounds.) The author does not deal with the environmental, medical, and biological aspects of polyarenes; thus, it may prove a disappointment to the environmental chemist.

  19. Interstellar Polycyclic Aromatic Compounds and Astrophysics

    NASA Technical Reports Server (NTRS)

    Hudgins, Douglas M.; DeVincenzi, Donald (Technical Monitor)

    2001-01-01

    Over the past fifteen years, thanks to significant, parallel advancements in observational, experimental, and theoretical techniques, tremendous strides have been made in our understanding of the role polycyclic aromatic compounds (PAC) in the interstellar medium (ISM). Twenty years ago, the notion of an abundant population of large, carbon rich molecules in the ISM was considered preposterous. Today, the unmistakable spectroscopic signatures of PAC - shockingly large molecules by previous interstellar chemistry standards - are recognized throughout the Universe. In this paper, we will examine the interstellar PAC model and its importance to astrophysics, including: (1) the evidence which led to inception of the model; (2) the ensuing laboratory and theoretical studies of the fundamental spectroscopic properties of PAC by which the model has been refined and extended; and (3) a few examples of how the model is being exploited to derive insight into the nature of the interstellar PAC population.

  20. Interstellar Polycyclic Aromatic Compounds and Astrophysics

    NASA Technical Reports Server (NTRS)

    Hodgins, Douglas M.; DeVincenzi, Donald (Technical Monitor)

    1999-01-01

    Polycyclic aromatic compounds (PACs), a class of organic molecules whose structures are characterized by the presence of two or more fused aromatic rings, have been the subject of astrophysical interest for nearly two decades. Large by interstellar standards (from as few as 20 to perhaps as many as several hundred atoms), it has been suggested that these species are among the most abundant interstellar molecules impacting a wide range of astrophysical phenomena including: the ubiquitous family of infrared emission bands observed in an ever-increasing assortment of astronomical objects; the subtle but rich array of discrete visible/near-infrared interstellar molecular absorption features known as the diffuse interstellar bands (DIBs); the broad near-infrared quasi-continuum observed in a number of nebulae known as excess red emission (ERE); the interstellar ultraviolet extinction curve and broad '2200 Angstrom bump'; the heating/cooling mechanisms of interstellar clouds. Nevertheless, until recently a lack of good-quality laboratory spectroscopic data on PACs under astrophysically relevant conditions (i.e. isolated, ionized molecules; ionized molecular clusters, etc.) has hindered critical evaluation and extension of this model

  1. PHOTOTOXICITY OF POLYCYCLIC AROMATIC HYDROCARBONS IN COASTAL GREAT LAKES WATERS

    EPA Science Inventory

    Photoinduced toxicity is the exacerbated toxicity of environmental contaminants by UV radiation. Photoinduced toxicity of polycyclic aromatic hydrocarbons (PAHs) has been well established in the laboratory for numerous aquatic species including larval fish. The contaminants sub-p...

  2. POLYCYCLIC AROMATIC HYDROCARBON (PAH) EXPOSURE OF 257 PRESCHOOL CHILDREN

    EPA Science Inventory

    We investigated the polycyclic aromatic hydrocarbon (PAH) exposure of 257 preschool children and their adult caregivers in their everyday environments. Participants were recruited randomly from eligible homes and daycare centers within six North Carolina (NC) and six Ohio (OH) c...

  3. ADSORPTION OF POLYCYCLIC AROMATIC HYDROCARBONS IN AGED HARBOR SEDIMENTS

    EPA Science Inventory

    Polycyclic aromatic hydrocarbons (PAHs) are a group of hydrophobic organic contaminants which have low aqueous solubilities and are common pollutants in harbor sediments. Adsorption and desorption isotherms for PAHs are conducted to study the abiotic sorption of PAHs in uncontami...

  4. PHOTOTOXICITY OF POLYCYCLIC AROMATIC HYDROCARBONS IN COASTAL GREAT LAKES WATERS

    EPA Science Inventory

    Photoinduced toxicity is the exacerbated toxicity of environmental contaminants by UV radiation. Photoinduced toxicity of polycyclic aromatic hydrocarbons (PAHs) has been well established in the laboratory for numerous aquatic species including larval fish. The contaminants sub-p...

  5. ADSORPTION OF POLYCYCLIC AROMATIC HYDROCARBONS IN AGED HARBOR SEDIMENTS

    EPA Science Inventory

    Polycyclic aromatic hydrocarbons (PAHs) are a group of hydrophobic organic contaminants which have low aqueous solubilities and are common pollutants in harbor sediments. Adsorption and desorption isotherms for PAHs are conducted to study the abiotic sorption of PAHs in uncontami...

  6. A combined EPR and DFT study of the overcrowded aromatic radical cations from Friedel-Crafts alkylation reactions

    NASA Astrophysics Data System (ADS)

    Wang, Tao; Tang, Fu Ming; Wu, Yi Fang

    2011-09-01

    Electron paramagnetic resonance and electron-nuclear double resonance methods were used to study the polycyclic aromatic radical cations produced in a Friedel-Crafts alkylating system, and the following radical cations were indentified: 3,6,11,14-tetramethyl dibenzo (a, c) triphylene and 2,6-dimethyl-9,10-di(p-methylbenzyl) anthracene radical cations. The results indicate that the observed electron paramagnetic resonance spectra are due to overcrowded polycyclic aromatic radical cations formed from the parent hydrocarbons. It is suggested that benzyl halides produced in the Friedel-Crafts alkylation reactions undergo Scholl condensation to give polycyclic aromatic hydrocarbons, which are converted into corresponding polycyclic aromatic radical cations in the presence of AlCl 3. We carried out the theoretical calculation of the isotropic 1H hyperfine coupling constants for studied both PAHs radical cations. The results indicate that the IEFPCM-DFT calculation at B3LYP level with 6-31++G(d,p), EPRII and EPRIII basis sets could well support the experimental hfcc assignment of the observed radicals. Optimized geometry indicates that the aromatic rings in both PAHs radical cations twisted significantly out of co-planarity.

  7. First results from the oil sands passive air monitoring network for polycyclic aromatic compounds.

    PubMed

    Schuster, Jasmin K; Harner, Tom; Su, Ky; Mihele, Cristian; Eng, Anita

    2015-03-03

    Results are reported from an ongoing passive air monitoring study for polycyclic aromatic compounds (PACs) in the Athabasca oil sands region in Alberta, Canada. Polyurethane foam (PUF) disk passive air samplers were deployed for consecutive 2-month periods from November 2010 to June 2012 at 17 sites. Samples were analyzed for polycyclic aromatic hydrocarbons (PAHs), alkylated PAHs, dibenzothiophene and its alkylated derivatives (DBTs). Relative to parent PAHs, alkylated PAHs and DBTs are enriched in bitumen and therefore considered to be petrogenic markers. Concentrations in air were in the range 0.03-210 ng/m(3), 0.15-230 ng/m(3) and 0.01-61 ng/m(3) for ∑PAHs, ∑alkylated PAHs and ΣDBTs, respectively. An exponential decline of the PAC concentrations in air with distance from mining areas and related petrogenic sources was observed. The most significant exponential declines were for the alkylated PAHs and DBTs and attributed to their association with mining-related emissions and near-source deposition, due to their lower volatility and greater association with depositing particles. Seasonal trends in concentrations in air for PACs were not observed for any of the compound classes. However, a forest fire episode during April to July 2011 resulted in greatly elevated PAH levels at all passive sampling locations. Alkylated PAHs and DBTs were not elevated during the forest fire period, supporting their association with petrogenic sources. Based on the results of this study, an "Athabasca PAC profile" is proposed as a potential source marker for the oil sands region. The profile is characterized by ∑PAHs/∑Alkylated PAHs = ∼0.2 and ∑PAHs/∑DBTs = ∼5.

  8. Capillary electrochromatography. Analysis of polycyclic aromatic hydrocarbons

    SciTech Connect

    Yan, C.; Dadoo, R.; Zhao, H.; Zare, R.N.; Rakestraw, D.J.

    1995-07-01

    Electrochromatography is utilized to separate a mixture of 16 different polycyclic aromatic hydrocarbons (PAHs). Fused-silica capillary columns ranging in size from 50 to 150 {mu}m i.d. were packed (20-40-cm sections) with 3-{mu}m octadecylsilica particles. A potential of 15-30 kV is applied across the 30-50-cm total length capillary column to generate electroosmotic flow that carries the PAHs through the stationary phase. An intracavity-doubled argon ion laser operating at 257 nm is used to detect the PAHs by laser-induced fluorescence. Efficiencies up to 400 000 theoretical plates/m are obtained when detection is performed within the column packing and up to 150 000 theoretical plates/m when detection is performed following a frit (used to hold the packing). The reproducibility of the peak retention times is better than 2% (RSD). The limits of detection for individual PAHs range between 10{sup -17} and 10{sup -20} mol (10{sup -9}-10{sup -11} M), with a linear response spanning 4 orders of magnitude in concentration. 12 refs., 4 figs., 2 tabs.

  9. Polycyclic aromatic hydrocarbon molecules in astrophysics

    NASA Astrophysics Data System (ADS)

    Rastogi, Shantanu; Pathak, Amit; Maurya, Anju

    2013-06-01

    Polycyclic aromatic hydrocarbon (PAH) molecules are responsible for the mid-infrared emission features. Their ubiquitous presence in almost all types of astrophysical environments and related variations in their spectral profilesmake them an important tool to understand the physics and chemistry of the interstellar medium. The observed spectrum is generally a composite superposition of all different types of PAHs possible in the region. In the era of space telescopes the spectral richness of the emission features has enhanced their importance as probe and also the need to understand the variations with respect to PAH size, type and ionic state. Quantum computational studies of PAHs have proved useful in elucidating the profile variations and put constraints on the possible types of PAHs in different environments. The study of PAHs has also significantly contributed to the problems of diffuse interstellar bands (DIBs), UV extinction and understanding the chemistry of the formation of complex organics in space. The review highlights the results of various computational models for the understanding of infrared emission features, the PAH-DIB relation, formation of prebiotics and possible impact in the understanding of far-infrared features.

  10. Partition of polycyclic aromatic hydrocarbons on organobentonites from water.

    PubMed

    Chen, B L; Zhu, L Z

    2001-04-01

    A series of organobentonites synthesized by exchanging organic cation such as dodecyltri-methylammonium (DTMA), benzyldimethyltetradecylammonium (BDTDA), cetyltrimethyl-ammonium (CTMA), octodeyltrimethylammonium (OTMA) on bentonite. The optimal condition, properties and mechanisms for the organobentonites to sorb phenanthrene, anthracene, naphthalene, acenaphthene in water were investigated in detail. The partition behavior was determined for four polycyclic aromatic hydrocarbons (PAHs), such as naphthalene, phenanthrene, anthracene and acenaphthene, from water to a series of organobentonites. The interlayer spacings and organic carbon contents of organobentonites, removal rate and sorption capacities for organobentonites to treat phenanthrene, anthracene, naphthalene, acenaphthene were correlated to the length of alkyl chains and the amounts of cation surfactant exchanged on the bentonite. Phenanthrene, anthracene, naphthalene, and acenaphthene sorption to organobentonites were characterized by linear isotherms, indicating solute partition between water and the organic phase composed of the large alkyl functional groups of quaternary ammonium cations. PAHs distribution coefficients (Kd) between organobentonites and water were proportional to the organic carbon contents of organobentonites. However, the partition coefficients (Koc) were nearly constants for PAHs in the system of organobentonite-water. The Koc of phenanthrene, anthracene, naphthalene, acenaphthene were 2.621 x 10(5), 2.106 x 10(5), 2.247 x 10(4), 5.085 x 10(4), respectively. The means Koc values on the organobentonites are about ten to twenty times larger than the values on the soils/sediments, what is significant prerequisite for organobentonite to apply to remediation of pollution soil and groundwater. The sorption mechanism was also evaluated from octanol-water partition coefficients and aqueous solubility of PAHs. The correlations between 1gKoc and 1gKow, 1gKoc and 1gS for PAHs in the system of

  11. Bioavailability of polycyclic aromatic hydrocarbons in the North Sea

    SciTech Connect

    Utvik, T.I.R. . Environmental Section); Johnsen, S. )

    1999-06-15

    Semipermeable membrane devices (SPMDs) and blue mussels (Mytilus edulis) were used to determine the bioavailable fraction of polycyclic aromatic hydrocarbons (PAHs) from oil field produced water in the North Sea. The SPMDs and mussels were deployed at 5, 10, and 50 m depth; 100 and 300 m downstream the discharge point; and at a reference site 16 km away. In both SPMDs and mussels, the concentration of PAHs increased significantly toward the discharge point, with the strongest contribution from the lower molecular weight compounds (naphthalene, phenanthrene, dibenzothiophene, and their C1-C3 alkyl homologues). The relative increase in PAH concentration from the reference site to the site at 100 m was higher for mussels than for the SPMDs. The SPMDs reflect the water-soluble fraction of the PAHs, which is probably the most important route of exposure for organisms at lower trophic levels and presumably also the fraction available for uptake by a respiratory route. Residues in the mussels represent both the water-soluble and particle-bound fraction and give information about bioavailability of the PAHs for organisms at higher trophic levels. The results of this study suggest that both techniques give important information about the bioavailability of PAHs to marine organisms.

  12. An Evaluation of Polycyclic Aromatic Hydrocarbon Uptake into Polyethylene Samplers

    NASA Astrophysics Data System (ADS)

    Martynowych, D. J.; McDonough, C.; Lohmann, R.

    2013-12-01

    Polyethylene passive samplers (PEs) are simple reliable tools that have been widely used in the detection of hydrophobic organic compounds. Thick (>200μm or greater) PEs have important applications to specific sampling scenarios including biological assays, deployment on ships and aircraft (towing) and long term sampling, however little is known about their uptake kinetics. This study aimed to develop an accurate understanding of the uptake kinetics of these thick PEs. PE passive samplers of equal surface area, but differing thicknesses were co-deployed in the surface water and air of lower Narragansett Bay in 2013 to characterize differences in their uptake of polycyclic aromatic hydrocarbons (PAHs). PE samplers of approximately 50, 800, and 1600μm thicknesses were analyzed for 38 parent and alkylated PAHs, with replicate sampler reproducibility mostly within 25%. A number of smaller PAHs (typically those with a molecular weight less than 180) analyzed over a 4 week deployment equilibrated, while the larger molecules remained in the linear or curve linear uptake stages. Results from a second, 24 week deployment of 800μm and 1600μm samplers in surface waters suggest that all 38 compounds studied remained in the linear uptake stage. The PE-weight normalized concentration ratio of 1600μm to 800μm sampler fell below 1 for all analytes, implying equilibrium had not been established.

  13. 40 CFR 721.10058 - Reaction product of alkylphenol, aromatic cyclicamine, alkyl diglycidyl dibenzene, and...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Reaction product of alkylphenol... Reaction product of alkylphenol, aromatic cyclicamine, alkyl diglycidyl dibenzene, and formaldehyde... identified generically as reaction product of alkylphenol, aromatic cyclicamine, alkyl diglycidyl...

  14. 40 CFR 721.10058 - Reaction product of alkylphenol, aromatic cyclicamine, alkyl diglycidyl dibenzene, and...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Reaction product of alkylphenol... Reaction product of alkylphenol, aromatic cyclicamine, alkyl diglycidyl dibenzene, and formaldehyde... identified generically as reaction product of alkylphenol, aromatic cyclicamine, alkyl diglycidyl...

  15. 40 CFR 721.10058 - Reaction product of alkylphenol, aromatic cyclicamine, alkyl diglycidyl dibenzene, and...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Reaction product of alkylphenol... Reaction product of alkylphenol, aromatic cyclicamine, alkyl diglycidyl dibenzene, and formaldehyde... identified generically as reaction product of alkylphenol, aromatic cyclicamine, alkyl diglycidyl...

  16. 40 CFR 721.10058 - Reaction product of alkylphenol, aromatic cyclicamine, alkyl diglycidyl dibenzene, and...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Reaction product of alkylphenol... Reaction product of alkylphenol, aromatic cyclicamine, alkyl diglycidyl dibenzene, and formaldehyde... identified generically as reaction product of alkylphenol, aromatic cyclicamine, alkyl diglycidyl...

  17. 40 CFR 721.10058 - Reaction product of alkylphenol, aromatic cyclicamine, alkyl diglycidyl dibenzene, and...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Reaction product of alkylphenol... Reaction product of alkylphenol, aromatic cyclicamine, alkyl diglycidyl dibenzene, and formaldehyde... identified generically as reaction product of alkylphenol, aromatic cyclicamine, alkyl diglycidyl...

  18. Potential Metabolic Activation of a Representative C2-Alkylated Polycyclic Aromatic Hydrocarbon 6-Ethylchrysene Associated with the Deepwater Horizon Oil Spill in Human Hepatoma (HepG2) Cells

    PubMed Central

    2016-01-01

    Exposure to polycyclic aromatic hydrocarbons (PAHs) is the major human health hazard associated with the Deepwater Horizon oil spill. C2-Chrysenes are representative PAHs present in crude oil and could contaminate the food chain. We describe the metabolism of a C2-chrysene regioisomer, 6-ethylchrysene (6-EC), in human HepG2 cells. The structures of the metabolites were identified by HPLC-UV-fluorescence detection and LC-MS/MS. 6-EC-tetraol isomers were identified as signature metabolites of the diol-epoxide pathway. O-Monomethyl-O-monosulfonated-6-EC-catechol, its monohydroxy products, and N-acetyl-l-cysteine(NAC)-6-EC-ortho-quinone were discovered as signature metabolites of the ortho-quinone pathway. Potential dual metabolic activation of 6-EC involving the formation of bis-electrophiles, i.e., a mono-diol-epoxide and a mono-ortho-quinone within the same structure, bis-diol-epoxides, and bis-ortho-quinones was observed as well. The identification of 6-EC-tetraol, O-monomethyl-O-monosulfonated-6-EC-catechol, its monohydroxy products, and NAC-6-EC-ortho-quinone supports potential metabolic activation of 6-EC by P450 and AKR enzymes followed by metabolic detoxification of the ortho-quinone through interception of its redox cycling capability by catechol-O-methyltransferase and sulfotransferase enzymes. The tetraols and catechol conjugates could be used as biomarkers of human exposure to 6-EC resulting from oil spills. PMID:27054409

  19. Comparative analysis of polycyclic aromatic sulfur heterocycles isolated from four shale oils. [Polycyclic aromatic sulfur heterocycles; thiophenes

    SciTech Connect

    Willey, C.; Pelroy, R.; Stewart, D.

    1981-12-01

    This report describes the isolation of sulfur heterocycle fractions from four shale oils (Paraho, Geokinetics, Occidental, and Rio Blanco), the use of capillary column gas chromatography and mass spectrometry for the identification of individual mixture components, and a reverse (Ames) and forward mutation assay with Salmonella typhimurium to screen for possible health hazards. The major components of the Polycyclic Aromatic Sulfur Heterocycles (PASH) fractions for all four shale oils were found to be two- to three-ringed parent and alkylated thiophene compounds. In all cases the PASH fractions showed no more specific mutagenic response than the neutral PAC fractions from which they were isolated. The only mutagenic response which was detected in the PASH fractions was for the Rio Blanco shale oil and showed specific mutagenic response similar to the neutral PAC fraction from which it was isolated. Finally, the forward mutation 8-azaguanine test was apparently more sensitive than the Ames histidine reversion test in detecting mutagenic activity for the chemical fractions from the shale oils.

  20. Polycyclic Aromatic Hydrocarbons in Fine Particulate Matter ...

    EPA Pesticide Factsheets

    This study measured polycyclic aromatic hydrocarbon (PAH) composition in particulate matter emissions from residential cookstoves. A variety of fuel and cookstove combinations were examined, including: (i) liquid petroleum gas (LPG), (ii) kerosene in a wick stove, (iii) wood (10% and 30% moisture content on a wet basis) in a forced-draft fan stove, and (iv) wood in a natural-draft rocket cookstove. LPG combustion had the highest thermal efficiency (~57%) and the lowest PAH emissions per unit fuel energy, resulting in the lowest PAH emissions per useful energy delivered (MJd). The average benzo[a]pyrene (B[a]P) emission factor for LPG was 0.842 µg/MJd; the emission rate was 0.043 µg/min. The highest PAH emissions were from wood burning in the natural-draft stove (209-700 µg B[a]P/MJd). PAH emissions from kerosene were significantly lower than those from the wood burning in the natural-draft cookstove, but higher than those from LPG. It is expected that in rural regions where LPG and kerosene are unavailable or unaffordable, the forced-draft fan stove may be an alternative because its emission factor (5.17-8.07 µg B[a]P/MJd) and emission rate (0.52-0.57 µg/min) are similar to kerosene (5.36 µg B[a]P/MJd and 0.45 µg/min). Compared with wood combustion emissions, LPG stoves emit less total PAH emissions and less fractions of high molecular weight PAHs. Relatively large variations in PAH emissions from LPG call for additional future tests to identify the major

  1. From Interstellar Polycyclic Aromatic Hydrocarbons to Astrobiology

    NASA Astrophysics Data System (ADS)

    Hudgins, D.

    Tremendous strides have been made in our understanding of interstellar material over the past twenty years thanks to significant, parallel developments in observational astronomy and laboratory astrophysics. Before this time, the composition of interstellar dust was largely guessed-at, and the existence of large, gas phase, carbon rich molecules in the interstellar medium (ISM) considered impossible. Today, the telltale infrared spectral signature of polycyclic aromatic hydrocarbons (PAHs) and related materials is recognized at all stages of the lifecycle of interstellar matter and it is widely accepted that these species are both abundant and widespread throughout our galaxy and the universe. In the first part of this talk, we will review the spectroscopic evidence that forms the basis for the interstellar PAH model. We will then use this as a basis to explore how this model can be applied to track the chemical evolution of the PAH population as it is produced in the circumstellar outflows of dying stars, cycled through the various phases of the ISM, and finally incorporated into forming pla n e t a r y systems. Nevertheless, despite the fact that PAHs likely represent the single largest molecular reservoir of organic carbon in evolving planetary systems, they are not what would be considered "biogenic" molecules.Consequently, we will conclude by considering the likely chemical modifications that PAHs undergo under conditions that simulate those found in cold, dark interstellar clouds and evolving planetary systems. Special attention will be paid to the potential for transforming this rich repository of pre-biotic organic "ore" into materials of greater Astrobiological significance. For further information on the research activities of the Astrochemistry Laboratory at NASA Ames Research Center, visit our website at http://www.astrochemistry.org.

  2. Polycyclic aromatic hydrocarbon processing by cosmic rays

    NASA Astrophysics Data System (ADS)

    Micelotta, E. R.; Jones, A. P.; Tielens, A. G. G. M.

    2011-02-01

    Context. Cosmic rays are present in almost all phases of the ISM. Polycyclic aromatic hydrocarbons (PAHs) and cosmic rays represent an abundant and ubiquitous component of the interstellar medium. However, the interaction between them has never before been fully investigated. Aims: To study the effects of cosmic ray ion (H, He, CNO and Fe-Co-Ni) and electron bombardment of PAHs in galactic and extragalactic environments. Methods: We calculate the nuclear and electronic interactions for collisions between PAHs and cosmic ray ions and electrons with energies between 5 MeV/nucleon and 10 GeV, above the threshold for carbon atom loss, in normal galaxies, starburst galaxies and cooling flow galaxy clusters. Results: The timescale for PAH destruction by cosmic ray ions depends on the electronic excitation energy E0 and on the amount of energy available for dissociation. Small PAHs are destroyed faster, with He and the CNO group being the more effective projectiles. For electron collisions, the lifetime is independent of the PAH size and varies with the threshold energy T0. Conclusions: Cosmic rays process the PAHs in diffuse clouds, where the destruction due to interstellar shocks is less efficient. In the hot gas filling galactic halos, outflows of starburst galaxies and intra-cluster medium, PAH destruction is dominated by collisions with thermal ions and electrons, but this mechanism is ineffective if the molecules are in denser cloudlets and isolated from the hot gas. Cosmic rays can access the denser clouds and together with X-rays will set the lifetime of those protected PAHs. This limits the use of PAHs as a "dye" for tracing the presence of cold entrained material.

  3. Polycyclic aromatic hydrocarbon emissions from motorcycles

    NASA Astrophysics Data System (ADS)

    Yang, Hsi-Hsien; Hsieh, Lien-Te; Liu, Hsu-Chung; Mi, Hsiao-Hsuan

    Emissions of polycyclic aromatic hydrocarbons (PAHs, 2-7 ring) and regulated air pollutants (CO, HC, NO x, PM) from 2-stroke carburetor (2-Stk/Cb), 4-stroke carburetor (4-Stk/Cb) and 4-stroke fuel injection (4-Stk/FI) motorcycles were investigated by testing these vehicles on a chassis dynamometer. Exhaust samplings were carried out on diluted exhausts in a dilution tunnel connected to a constant volume sampling system. Measurements were performed on a standard driving cycle. The results reveal that low molecular weight PAHs (especially naphthalene) dominated in the exhaust gas. The averages of soluble organic fractions were 86.4%, 46.3% and 48.9% for the 2-Stk/Cb, 4-Stk/Cb and 4-Stk/FI motorcycles, respectively. PAH emissions are greater from cold-start driving than those from hot-start driving cycle for all these three kinds of motorcycles. Total PAH emission factors were 8320, 5990 and 3390 μg km -1 for the in-used 2-Stk/Cb, 4-Stk/Cb and 4-Stk/FI motorcycles, respectively. PAH emission factors were the largest for the 2-Stk/Cb motorcycles. Besides, the 2-Stk/Cb motorcycle had the largest total BaP equivalent emission factor of 10.8 μg km -1, indicating that the emission exhaust from the 2-Stk/Cb motorcycle was most carcinogenic. HC, PM and PAH emissions were the lowest for the 4-Stk/FI motorcycles. The correlation coefficient between CO and total PAH emissions for all the test motorcycles was 0.51, indicating that CO and PAH emissions are not highly correlated.

  4. [Some toxicological aspects of polycyclic aromatic hydrocarbons (PAHs) effects].

    PubMed

    Zasadowski, Arkadiusz; Wysocki, Adam

    2002-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants. They are found through environment in the air, in the soil, in water, in plants, and also in food. PAHs are formed during pyrolisis and the incomplete combustion of organic materials. PAHs can be man-made or occur naturally. They undergo metabolic activation after entering the mammalian cells to highly toxic reactive metabolite intermediates and can irreversibly damage cellular macromolecules (DNA, proteins, lipids). Polycyclic aromatic hydrocarbons represent a class of toxicological compounds which can create a variety of hazardous effects in vivo, including cytotoxicity, genotoxicity, immunotoxicity, teratogenicity and carcinogenesis described in present paper.

  5. Study of the origin of polycyclic aromatic hydrocarbons in water of Lake Baikal

    NASA Astrophysics Data System (ADS)

    Semenova, M. Yu.; Snytko, V. A.; Marinaite, I. I.

    2017-06-01

    The concentration of polycyclic aromatic hydrocarbons in the water of Lake Baikal is estimated. The published data on the composition of polycyclic aromatic hydrocarbons in industrial and communal emissions and in crude oils are analyzed. Anthropogenic sources of lake water contamination are revealed. It is concluded that polycyclic aromatic hydrocarbons enter the lake as a result of natural oil release.

  6. Dry deposition of polycyclic aromatic compounds to various land covers in the Athabasca oil sands region

    NASA Astrophysics Data System (ADS)

    Zhang, Leiming; Cheng, Irene; Wu, Zhiyong; Harner, Tom; Schuster, Jasmin; Charland, Jean-Pierre; Muir, Derek; Parnis, J. Mark

    2015-09-01

    A framework was developed to estimate dry deposition of polycyclic aromatic compounds (PACs), including 17 polycyclic aromatic hydrocarbons (PAHs), 21 alkylated PAHs, and 5 parent and alkylated dibenzothiophenes (DBTs), to various land covers surrounding three monitoring sites in the Athabasca oil sands region. Modeled dry deposition velocities for various gaseous PACs and over various land covers were mostly in the range of 0.01-0.5 cm s-1 with median and annual mean values between 0.08 and 0.24 cm s-1, comparable with literature values obtained from field studies. Annual dry deposition of the sum of PAHs was estimated to range from 330 to 560 μg m-2 over forested canopies surrounding the three sites and from 270 to 490 μg m-2 over grass and shrubs. The corresponding values are 3920-5380 and 2850-4920 μg m-2 for the sum of 21 alkylated PAHs, and are 230-1120 and 450-930 μg m-2 for the sum of 5 DBTs. The three monitoring sites are situated nearby the Athabasca River, and the direct annual atmospheric dry deposition to water surface was estimated to range from 350 to 500, 3170 to 4530, and 170 to 840 μg m-2 for PAHs, alkylated PAHs, and DBTs, respectively. Alkylated PAHs contributed 80% of the total dry and 60% of the total wet deposition budget, suggesting the importance of including this group of PAHs in the atmospheric deposition budget estimation for subsequent ecosystem impact studies.

  7. Closed-Shell Polycyclic Aromatic Hydrocarbon Cations: A New Category of Interstellar Polycyclic Aromatic Hydrocarbons

    NASA Technical Reports Server (NTRS)

    Hudgins, Douglas M.; Bauschlicher, Charles W., Jr.; Allamandola, Louis J.; DeVincenzi, Donald (Technical Monitor)

    2001-01-01

    Density functional theory has been employed to calculate the harmonic frequencies and intensities of a range of polycyclic aromatic hydrocarbon (PAH) cations that explore both size and electronic structure effects of the infrared spectroscopic properties of these species. The sample extends the size range of PAH species considered to more than 50 carbon atoms and includes several representatives from each of two heretofore unexplored categories of PAH cations: (1) fully benzenoid PAH cations whose carbon skeleton is composed of an odd number of carbon atoms (C(sub odd) PAHs); and (2) protonated PAH cations (HPAH+). Unlike the radical electronic structures of the PAH cations that have been the subject of previous theoretical and experimental work, the species in these two classes have a closed-shell electronic configuration. The calculated spectra of circumcoronene, C54H18 in both neutral and (radical) cationic form are also reported and compared with those of the other species. Overall, the C(sub odd) PAHs spectra are dominated by strong CC stretching modes near 1600 cm(exp -1) and display spectra that are remarkably insensitive to molecular size. The HPAH+ species evince a more complex spectrum consistent with the added contributions of aliphatic modes and their generally lower symmetry. Finally, for both classes of closed-shell cations, the intensity of the aromatic CH stretching modes is found to increase with molecular size far out of proportion with the number of CH groups, approaching a value more typical of neutral PAHs for the largest species studied.

  8. Closed-Shell Polycyclic Aromatic Hydrocarbon Cations: A New Category of Interstellar Polycyclic Aromatic Hydrocarbons

    NASA Technical Reports Server (NTRS)

    Hudgins, Douglas M.; Bauschlicher, Charles W., Jr.; Allamandola, Louis J.; DeVincenzi, Donald (Technical Monitor)

    2001-01-01

    Density functional theory has been employed to calculate the harmonic frequencies and intensities of a range of polycyclic aromatic hydrocarbon (PAH) cations that explore both size and electronic structure effects of the infrared spectroscopic properties of these species. The sample extends the size range of PAH species considered to more than 50 carbon atoms and includes several representatives from each of two heretofore unexplored categories of PAH cations: (1) fully benzenoid PAH cations whose carbon skeleton is composed of an odd number of carbon atoms (C(sub odd) PAHs); and (2) protonated PAH cations (HPAH+). Unlike the radical electronic structures of the PAH cations that have been the subject of previous theoretical and experimental work, the species in these two classes have a closed-shell electronic configuration. The calculated spectra of circumcoronene, C54H18 in both neutral and (radical) cationic form are also reported and compared with those of the other species. Overall, the C(sub odd) PAHs spectra are dominated by strong CC stretching modes near 1600 cm(exp -1) and display spectra that are remarkably insensitive to molecular size. The HPAH+ species evince a more complex spectrum consistent with the added contributions of aliphatic modes and their generally lower symmetry. Finally, for both classes of closed-shell cations, the intensity of the aromatic CH stretching modes is found to increase with molecular size far out of proportion with the number of CH groups, approaching a value more typical of neutral PAHs for the largest species studied.

  9. AROMATIC AND POLYCYCLIC AROMATIC HYDROCARBON FORMATION IN A LAMINAR PREMIXED N-BUTANE FLAME. (R825412)

    EPA Science Inventory

    Abstract

    Experimental and detailed chemical kinetic modeling work has been performed to investigate aromatic and polycyclic aromatic hydrocarbon (PAH) formation pathways in a premixed, rich, sooting, n-butane¯oxygen¯argon burner s...

  10. AROMATIC AND POLYCYCLIC AROMATIC HYDROCARBON FORMATION IN A LAMINAR PREMIXED N-BUTANE FLAME. (R825412)

    EPA Science Inventory

    Abstract

    Experimental and detailed chemical kinetic modeling work has been performed to investigate aromatic and polycyclic aromatic hydrocarbon (PAH) formation pathways in a premixed, rich, sooting, n-butane¯oxygen¯argon burner s...

  11. Microbial Degradation of Polycyclic Aromatic Hydrocarbons and Characterization of Bacteria

    NASA Astrophysics Data System (ADS)

    Tikilili, P. V.; Chirwa, E. M. N.

    2010-01-01

    Biodegradation of polycyclic aromatic hydrocarbons was studied. Naphthalene was used as a model compound to represent these compounds. Low initial concentrations of naphthalene in a range of 30-60 mg/L were completely degraded after incubation for 15 hrs by consortia from a landfill soil while consortia from minewater took more that 29 hrs to reach complete degradation.

  12. THE RATES OF POLYCYCLIC AROMATIC HYDROCARBON EMISSIONS FROM INCENSE BURNING

    EPA Science Inventory

    The paper presents the results of experiments performed to determine the amounts of gas- and particle-phase polycyclic aromatic hydrocarbons (PAHS) in incense smoke. Ten brands of incense, 3 of stick, 2 of joss stick, and one each of cone, smudge bundle, rope, powder, and rock, w...

  13. THE RATES OF POLYCYCLIC AROMATIC HYDROCARBON EMISSIONS FROM INCENSE BURNING

    EPA Science Inventory

    The paper presents the results of experiments performed to determine the amounts of gas- and particle-phase polycyclic aromatic hydrocarbons (PAHS) in incense smoke. Ten brands of incense, 3 of stick, 2 of joss stick, and one each of cone, smudge bundle, rope, powder, and rock, w...

  14. METHODOLOGY OF AMBIENT AIR MONITORING FOR POLYCYCLIC AROMATIC HYDROCARBONS

    EPA Science Inventory

    In the last decade, several studies of polycyclic aromatic hydrocarbons (PAH) in ambient air in the U.S. specifically investigated (1) the sampling efficiency of two sorbents for PAH in air: XAD-2 and polyurethane foam (PUP); (2) the storage stability of PAH on quartz fiber fil...

  15. METHODOLOGY OF AMBIENT AIR MONITORING FOR POLYCYCLIC AROMATIC HYDROCARBONS

    EPA Science Inventory

    In the last decade, several studies of polycyclic aromatic hydrocarbons (PAH) in ambient air in the U.S. specifically investigated (1) the sampling efficiency of two sorbents for PAH in air: XAD-2 and polyurethane foam (PUP); (2) the storage stability of PAH on quartz fiber fil...

  16. Modelling study of electron-beam polycyclic and nitro-polycyclic aromatic hydrocarbons treatment

    NASA Astrophysics Data System (ADS)

    Gerasimov, Gennady

    2007-01-01

    The efficiency of the electron-beam removal of harmful impurities from industrial flue gases was studied as applied to polycyclic and nitro-polycyclic aromatic hydrocarbons. The mathematical model of radiation-induced processes was proposed. The model includes aromatic molecules decomposition in gas-phase reactions, and their liquid-phase conversion in the aerosol droplets produced upon the binary volume condensation of water and sulfuric acid vapors. The presence of active species (atoms and radicals) in radiation zone and their reactions with aliphatic and aromatic hydrocarbons can result in an opposite effect: the formation of aromatic molecules and growth of their structure. Modelling study of such processes allows evaluating the efficiency of this purification technology at various initial conditions. Results of calculations are compared with available experimental data.

  17. Application of solid-phase microextraction to the determination of polycyclic aromatic sulfur heterocycles in Bohai Sea crude oils.

    PubMed

    Yang, Baijuan; Hou, Wei; Zhang, Kuiying; Wang, Xiaoru

    2013-08-01

    A simple and rapid solid-phase microextraction approach for the isolation of polycyclic aromatic sulfur heterocycles from the aromatic fraction of crude oil is described. 8-Hydroxyquinoline silica gel impregnated with palladium chloride was used as a sorbent material for extraction. Operational parameters of the extraction solvents have been evaluated and optimized. Benzothiophene, dibenzothiophene, and benzo[b]naphtho[1,2-d]thiophene and their C1-C4 alkyl derivatives were identified and quantified by GC-MS. Under optimum conditions, the limits of detection for benzothiophene, dibenzothiophene, and benzo[b]naphtho[1,2-d]thiophene were 0.277, 0.193, and 0.597 μg/g oil, respectively. The recoveries for the polycyclic aromatic sulfur heterocycles ranged from 81.5 to 92.1%, and the linear dynamic range was from 10 to 1000 ng/mL. The developed methodology was tested in the characterization of crude oil samples collected at the DY, SZ, ZH, and HC petroleum oil fields of the Bohai Sea. The results proved that SPE coupled with GC-MS is a promising tool for the quantitative analysis of polycyclic aromatic sulfur heterocycles in crude oils, especially for oil samples with low concentrations of polycyclic aromatic sulfur heterocycles.

  18. Effect of fluorine substitution on the aromaticity of polycyclic hydrocarbons.

    PubMed

    Kaipio, Mikko; Patzschke, Michael; Fliegl, Heike; Pichierri, Fabio; Sundholm, Dage

    2012-10-18

    The effect of fluorine substitution on the aromaticity of polycyclic hydrocarbons (PAH) is investigated. Magnetically induced current densities, current pathways, and current strengths, which can be used to assess molecular aromaticity, are calculated using the gauge-including magnetically induced current method (GIMIC). The degree of aromaticity of the individual rings is compared to those obtained using calculated nucleus-independent chemical shifts at the ring centers (NICS(0) and NICS(0)(zz)). Calculations of explicitly integrated current strengths for selected bonds show that the aromatic character of the investigated polycyclic hydrocarbons is weakened upon fluorination. In contrast, the NICS(0) values for the fluorinated benzenes increase noteworthy upon fluorination, predicting a strong strengthening of the aromatic character of the arene rings. The integrated current strengths also yield explicit current pathways for the studied molecules. The current pathways of the investigated linear polyacenes, pyrene, anthanthrene, coronene, ovalene, and phenanthro-ovalene are not significantly affected by fluorination. NISC(0) and NICS(0)(zz) calculations provide contradictory degrees of aromaticity of the fused individual ring. Obtained NICS values do not correlate with the current strengths circling around the individual rings.

  19. Experimental and modeling investigation of aromatic and polycyclic aromatic hydrocarbon formation in a premixed ethylene flame

    SciTech Connect

    Castaldi, M.J.; Marinov, N.M.; Melius, C.F.

    1996-02-01

    Experimental and detailed chemical kinetic modeling has been performed to investigate aromatic and polyaromatic hydrocarbon formation pathways in a rich, sooting, ethylene-oxygen-argon premixed flame. An atmospheric pressure, laminar flat flame operated at an equivalence ratio of 2.5 was used to acquire experimental data for model validation. Gas composition analysis was conducted by an on-line gas chromatograph/mass spectrometer (GC/MS) technique. Measurements were made in the flame and post-flame zone for a number of low molecular weight species, aliphatics, aromatics and polycyclic aromatic hydrocarbons (PAHs) ranging from two to five-aromatic fused rings. The modeling results show the key reaction sequences leading to aromatic and polycyclic aromatic hydrocarbon growth involve the combination of resonantly stabilized radicals. In particular, propargyl and 1-methylallenyl combination reactions lead to benzene and methyl substituted benzene formation, while polycyclic aromatics are formed from cyclopentadienyl radicals and fused rings that have a shared C{sub 5} side structure. Naphthalene production through the reaction step of cyclopentadienyl self-combination and phenanthrene formation from indenyl and cyclopentadienyl combination were shown to be important in the flame modeling study. The removal of phenyl by O{sub 2} leading to cyclopentadienyl formation is expected to play a pivotal role in the PAH or soot precursor growth process under fuel-rich oxidation conditions.

  20. Cobalt-Catalyzed Alkylation of Aromatic Amines by Alcohols.

    PubMed

    Rösler, Sina; Ertl, Michael; Irrgang, Torsten; Kempe, Rhett

    2015-12-07

    The implementation of inexpensive, Earth-abundant metals in typical noble-metal-mediated chemistry is a major goal in homogeneous catalysis. A sustainable or green reaction that has received a lot of attention in recent years and is preferentially catalyzed by Ir or Ru complexes is the alkylation of amines by alcohols. It is based on the borrowing hydrogen or hydrogen autotransfer concept. Herein, we report on the Co-catalyzed alkylation of aromatic amines by alcohols. The reaction proceeds under mild conditions, and selectively generates monoalkylated amines. The observed selectivity allows the synthesis of unsymmetrically substituted diamines. A novel Co complex stabilized by a PN5 P ligand catalyzes the reactions most efficiently. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Diesel particulate matter and polycyclic aromatic hydrocarbons in fire stations.

    PubMed

    Bott, Raymond C; Kirk, Katherine M; Logan, Michael B; Reid, Damien A

    2017-09-01

    Firefighters are known to be exposed to a wide variety of combustion products during operational and training firefighting activities. However, the potential for exposure to diesel exhaust emissions, recently classified as carcinogenic to humans by the International Agency for Research on Cancer, also exists within the fire station environment. In this study, concentrations of diesel particulate matter and polycyclic aromatic hydrocarbons have been measured in the engine bays, duty offices and dormitory areas of eight fire stations in Queensland, Australia. Operation of fire appliances and mechanical equipment during start of shift checks were found to contribute more strongly to overall engine bay diesel particulate matter concentrations than the number of fire appliance departures and returns. Polycyclic aromatic hydrocarbons were found to be transported further into fire station living environments than diesel particulate matter. This study highlights a number of potential strategies for reducing firefighter exposures to components of diesel engine exhaust in the fire station environment.

  2. Phylogenetic comparison of two polycyclic aromatic hydrocarbon-degrading mycobacteria.

    PubMed Central

    Govindaswami, M; Feldhake, D J; Kinkle, B K; Mindell, D P; Loper, J C

    1995-01-01

    Two mycobacterial strains previously isolated from fossil-fuel-contaminated environments and shown to degrade four- and/or five-ring polycyclic aromatic hydrocarbons were further characterized. The two strains, PYR-I and RJGII-135, had similar growth characteristics, colony morphologies, and scotochromogenic pigmentations. DNA amplification fingerprints obtained with total genomic DNA indicated some strain similarities but with several distinctly different bands. Moreover, phylogenetic analysis based upon essentially full-length 16S rRNA gene sequences separates the two strains as distinct species within the fast-growing group of mycobacteria. Although both strains are thermosensitive, strain PYR-I has the bulged U between positions 184 and 193 characteristic of thermotolerant mycobacteria. Both strains are of potential use for reintroduction into and bioremediation of polycyclic aromatic hydrocarbon-contaminated soils. PMID:7574631

  3. Direct photolysis of polycyclic aromatic hydrocarbons in drinking water sources.

    PubMed

    Sanches, S; Leitão, C; Penetra, A; Cardoso, V V; Ferreira, E; Benoliel, M J; Crespo, M T Barreto; Pereira, V J

    2011-09-15

    The widely used low pressure lamps were tested in terms of their efficiency to degrade polycyclic aromatic hydrocarbons listed as priority pollutants by the European Water Framework Directive and the U.S. Environmental Protection Agency, in water matrices with very different compositions (laboratory grade water, groundwater, and surface water). Using a UV fluence of 1500 mJ/cm(2), anthracene and benzo(a)pyrene were efficiently degraded, with much higher percent removals obtained when present in groundwater (83-93%) compared to surface water (36-48%). The removal percentages obtained for fluoranthene were lower and ranged from 13 to 54% in the different water matrices tested. Several parameters that influence the direct photolysis of polycyclic aromatic hydrocarbons were determined and their photolysis by-products were identified by mass spectrometry. The formation of photolysis by-products was found to be highly dependent on the source waters tested.

  4. Phylogenetic comparison of two polycyclic aromatic hydrogen-degrading mycobacteria

    SciTech Connect

    Govindaswami, M.; Loper, J.C.; Feldhake, D.J.

    1995-09-01

    Two mycobacterial strains previously isolated from fossil-fuel-contaminated environments and shown to degrade four- and/or five-ring polycyclic aromatic hydrocarbons were further characterized. The two strains, PYR-I and RJGII-135, had similar growth characteristics, colony morphologies, and scotochromogenic pigmentations. DNA amplification fringerprints obtained with total genomic DNA indicated some strain similarities but with several distinctly different bands. Moreover, phylogenetic analysis based upon essentially full-length 16S rRNA gene sequences separates the two strains as distinct species within the fast-growing group of mycobacteria. Although both strains are thermosensitive, strain PYR-I has the bulged U between positions 184 and 193 characteristic of thermotolerant mycobacteria. Both strains are of potential use for reintroduction into and bioremediation of polycyclic aromatic hydrocarbon-contaminated soils. 26 refs., 4 figs., 1 tab.

  5. Geochemical markers and polycyclic aromatic hydrocarbons in solvent extracts from diesel engine particulate matter.

    PubMed

    Fabiańska, Monika; Kozielska, Barbara; Bielaczyc, Piotr; Woodburn, Joseph; Konieczyński, Jan

    2016-04-01

    Exhaust particulate from compression ignition (CI) engines running on engine and chassis dynamometers was studied. Particulate dichloromethane extracts were qualitatively and quantitatively analyzed for polycyclic aromatic hydrocarbons (PAHs) and biomarkers by gas chromatography with flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS). PAH group profiles were made and the PAH group shares according to the number of rings (2 or 3; 4; 5 or more) as well as diagnostic indices were calculated. Values of geochemical ratios of selected biomarkers and alkyl aromatic hydrocarbons were compared with literature values. A geochemical interpretation was carried out using these values and biomarker and alkyl aromatic hydrocarbon distributions. It has been shown that geochemical features are unequivocally connected to the emission of fossil fuels and biofuels burned in CI engines. The effect of the exothermic combustion process is limited to low-molecular-weight compounds, which shows that the applied methodology permits source identification of PAHs coexisting in the particulate emitted.

  6. Dimerization of polycyclic aromatic hydrocarbons in soot nucleation.

    PubMed

    Zhang, Hong-Bo; You, Xiaoqing; Wang, Hongmiao; Law, Chung K

    2014-02-27

    A possible pathway of soot nucleation, in which localized π electrons play an important role in binding the polycyclic aromatic hydrocarbon (PAH) molecules having multiradical characteristics to form stable polymer molecules through covalent bonds, is studied using density functional and semiempirical methods. Results show that the number of covalent bonds formed in the dimerization of two identical PAHs is determined by the radical character, and the sites to form bonds are related to the aromaticity of individual six-membered ring structure. It is further shown that the binding energy of dimerization increases linearly with the diradical character in the range relevant to soot nucleation.

  7. THE INFRARED SPECTROSCOPY OF NEUTRAL POLYCYCLIC AROMATIC HYDROCARBON CLUSTERS

    SciTech Connect

    Ricca, Alessandra; Bauschlicher, Charles W. Jr.; Allamandola, Louis J. E-mail: Charles.W.Bauschlicher@nasa.gov

    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.

  8. Oxidation of polycyclic aromatic hydrocarbons under sulfate-reducing conditions

    USGS Publications Warehouse

    Coates, J.D.; Anderson, R.T.; Lovley, D.R.

    1996-01-01

    [14C]naphthalene and phenanthrene were oxidized to 14CO2 without a detectable lag under strict anaerobic conditions in sediments from San Diego Bay, San Diego, Calif., that were heavily contaminated with polycyclic aromatic hydrocarbons (PAHs) but not in less contaminated sediments. Sulfate reduction was necessary for PAH oxidation. These results suggest that the self-purification capacity of PAH-contaminated sulfate-reducing environments may be greater than previously recognized.

  9. Critically Evaluated Thermochemical Properties of Polycyclic Aromatic Hydrocarbons

    NASA Astrophysics Data System (ADS)

    Roux, María Victoria; Temprado, Manuel; Chickos, James S.; Nagano, Yatsuhisa

    2008-12-01

    Experimental thermochemical properties of benzene, toluene, and 63 polycyclic aromatic hydrocarbons, published within the period 1878-2008 (over 350 references), are reported. Available experimental data for the enthalpies of combustion used to calculate enthalpies of formation in the condensed state, combined with sublimation, vaporization, and fusion enthalpies, are critically evaluated. Whenever possible, recommended values for these thermochemical properties and for the enthalpies of formation in the gas state at T =298.15K are provided.

  10. Polycyclic aromatic hydrocarbons in cryogenic peat plateaus of northeastern Europe

    NASA Astrophysics Data System (ADS)

    Pastukhov, A. V.; Kaverin, D. A.; Gabov, D. N.

    2017-07-01

    The qualitative and quantitative composition of 14 polycyclic aromatic hydrocarbons (PAHs) in peat plateaus at the southern boundary of the permafrost zone in northeastern Europe, where degradation of permafrost occurs because of climate warming, has been studied by high-performance liquid chromatography in gradient mode. PAH concentrations vary from 150 to 3700 ng/g with their average content of about 1500 ± 1000 ng/g. The variation of data is primarily due to the large contribution of heavy PAHs.

  11. Current-voltage characteristics of a homologous series of polycyclic aromatic hydrocarbons.

    PubMed

    Böhme, Thilo; Simpson, Christopher D; Müllen, Klaus; Rabe, Jürgen P

    2007-01-01

    A novel alkyl-substituted polycyclic aromatic hydrocarbon (PAH) with D(2h) symmetry and 78 carbon atoms in the aromatic core (C78) was synthesized, thereby completing a homologous series of soluble PAH compounds with increasing size of the aromatic pi system (42, 60, and 78 carbon atoms). The optical band gaps were determined by UV/Vis and fluorescence spectroscopy in solution. Scanning tunneling microscopy (STM) and spectroscopy (STS) revealed diode-like current versus voltage (I-V) characteristics through individual aromatic cores in monolayers at the interface between the solution and the basal plane of graphite. The asymmetry of the current-voltage (I-V) characteristics increases with the increasing size of the aromatic core, and the concomitantly decreasing HOMO-LUMO gap. This is attributed to resonant tunneling through the HOMO of the adsorbed molecule, and an asymmetric position of the molecular species in the tunnel junction. Consistently, submolecularly resolved STM images at negative substrate bias are in good agreement with the calculated pattern for the electron densities of the HOMOs. The analysis provides the basis for tailoring rectification with a single molecule in an STM junction.

  12. Microbial degradation of petrochemical waste-polycyclic aromatic hydrocarbons.

    PubMed

    Fulekar, M H

    2017-01-01

    Petrochemical industry is one of the fastest growing industries. This industry has immense importance in the growth of economy and manufacture of large varieties of chemicals. The petrochemical industry is a hazardous group of industry generating hazardous waste containing organic and inorganic compounds. In spite of the present treatment process, the hazardous waste compounds are found untreated to the acceptable level and found discharged at soil-water environment resulting into the persistent organic-inorganic pollutant into the environment. The bioremediation will be the innovative techniques to remove the persistent pollutants in the environment. Petrochemical contaminated site was found to be a rich source of microbial consortium degrading polycyclic aromatic hydrocarbons. Indigenous microbial consortiums were identified and used for bioremediation of polycyclic aromatic hydrocarbons (naphthalene and anthracene) at the concentrations of 250, 500, and 750 ppm. The potential microorganism was also identified for naphthalene and anthracene, and their bioremediation was studied at varying concentrations. The bioremediation with consortium was found to be comparatively more effective than the potential microorganism used for bioremediation of each compound. Pseudomonas aeruginosa a potential organism was identified by 16S rRNA and further studied for the gene responsible for the PAH compounds. Indigenous microorganism as a consortium has been found effective and efficient source for remediation of organic compound-Polycyclic aromatic hydrocarbon and this will also be applicable to remediate the toxic compounds to clean up the environment.

  13. MODELING GALACTIC EXTINCTION WITH DUST AND 'REAL' POLYCYCLIC AROMATIC HYDROCARBONS

    SciTech Connect

    Mulas, Giacomo; Casu, Silvia; Cecchi-Pestellini, Cesare; Zonca, Alberto E-mail: silvia@oa-cagliari.inaf.it E-mail: azonca@oa-cagliari.inaf.it

    2013-07-01

    We investigate the remarkable apparent variety of galactic extinction curves by modeling extinction profiles with core-mantle grains and a collection of single polycyclic aromatic hydrocarbons. Our aim is to translate a synthetic description of dust into physically well-grounded building blocks through the analysis of a statistically relevant sample of different extinction curves. All different flavors of observed extinction curves, ranging from the average galactic extinction curve to virtually 'bumpless' profiles, can be described by the present model. We prove that a mixture of a relatively small number (54 species in 4 charge states each) of polycyclic aromatic hydrocarbons can reproduce the features of the extinction curve in the ultraviolet, dismissing an old objection to the contribution of polycyclic aromatic hydrocarbons to the interstellar extinction curve. Despite the large number of free parameters (at most the 54 Multiplication-Sign 4 column densities of each species in each ionization state included in the molecular ensemble plus the 9 parameters defining the physical properties of classical particles), we can strongly constrain some physically relevant properties such as the total number of C atoms in all species and the mean charge of the mixture. Such properties are found to be largely independent of the adopted dust model whose variation provides effects that are orthogonal to those brought about by the molecular component. Finally, the fitting procedure, together with some physical sense, suggests (but does not require) the presence of an additional component of chemically different very small carbonaceous grains.

  14. Composition, distribution, and characterization of polycyclic aromatic hydrocarbons in soil in Linfen, China

    SciTech Connect

    Fu, S.; Cheng, H.X.; Liu, Y.H.; Xia, X.J.; Xu, X.B.

    2009-02-15

    A total of 10 surface soil samples representing the entire area of Linfen City were collected and analyzed for the presence of 16 polycyclic aromatic hydrocarbons. The total polycyclic aromatic hydrocarbon concentration ranged from 1.1 to 63.7 {mu} g g{sup -1}. Analysis of the sources of contamination revealed that polycyclic aromatic hydrocarbons in the soil were derived from combustion sources. Specifically, the primary source of polycyclic aromatic hydrocarbons was coal combustion, but the samples were also effected to varying degrees by traffic emissions. Furthermore, increased levels of contamination were observed in northeast Linfen due to the distribution of industrial plants.

  15. 40 CFR 721.950 - Sodium salt of an alkylated, sulfonated aromatic (generic name).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., sulfonated aromatic (generic name). 721.950 Section 721.950 Protection of Environment ENVIRONMENTAL... Significant New Uses for Specific Chemical Substances § 721.950 Sodium salt of an alkylated, sulfonated... chemical substance identified generically as a sodium salt of an alkylated, sulfonated aromatic (PMN...

  16. 40 CFR 721.950 - Sodium salt of an alkylated, sulfonated aromatic (generic name).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., sulfonated aromatic (generic name). 721.950 Section 721.950 Protection of Environment ENVIRONMENTAL... Significant New Uses for Specific Chemical Substances § 721.950 Sodium salt of an alkylated, sulfonated... chemical substance identified generically as a sodium salt of an alkylated, sulfonated aromatic (PMN...

  17. Chemistry at the interior atoms of polycyclic aromatic hydrocarbons.

    PubMed

    Scott, Lawrence T

    2015-09-21

    For more than 150 years, chemical reactions that make new covalent bonds to polycyclic aromatic hydrocarbons (PAHs) have been confined almost exclusively to substitution and addition reactions on the perimeters of the compounds ("edge chemistry"). The "interior" atoms of PAHs, those belonging to three rings, almost never engage in new σ-bond-forming reactions. A compound with no edges, C60, was the first polycyclic carbon π-system observed to exhibit such reactivity. More recently, smaller subunits of C60, which we call geodesic polyarenes, have also been found to exhibit "fullerene-type chemistry" at their interior carbon atoms. These reactions are all reviewed together here for the first time. The review ends with speculation that σ-bond-forming reactions may also be observed someday even in certain planar, benzenoid PAHs, although no examples have yet been reported.

  18. Polycyclic aromatic hydrocarbons residues in sandstorm depositions in Beijing, China

    SciTech Connect

    Fu, S.; Li, K.; Xia, X.J.; Xu, X.B.

    2009-02-15

    This study was conducted to determine the concentration of 16 polycyclic aromatic hydrocarbons (PAHs) in sandstorm depositions in Beijing, China. The PAH concentrations in 13 samples collected in Beijing ranged from 0.18 to 3.52 {mu} g g{sup -1}. Analysis of the sources of contamination revealed that the PAHs were derived from a coal combustion source, although various effects of traffic emissions were also observed. Furthermore, the PAH levels in Beijing tended to be higher in the southeast. Finally, the Nemerow composite index revealed that the degree of pollution in the sandstorm depositions varied widely among sampling sites.

  19. Extraction Techniques for Polycyclic Aromatic Hydrocarbons in Soils

    PubMed Central

    Lau, E. V.; Gan, S.; Ng, H. K.

    2010-01-01

    This paper aims to provide a review of the analytical extraction techniques for polycyclic aromatic hydrocarbons (PAHs) in soils. The extraction technologies described here include Soxhlet extraction, ultrasonic and mechanical agitation, accelerated solvent extraction, supercritical and subcritical fluid extraction, microwave-assisted extraction, solid phase extraction and microextraction, thermal desorption and flash pyrolysis, as well as fluidised-bed extraction. The influencing factors in the extraction of PAHs from soil such as temperature, type of solvent, soil moisture, and other soil characteristics are also discussed. The paper concludes with a review of the models used to describe the kinetics of PAH desorption from soils during solvent extraction. PMID:20396670

  20. Microwave-assisted extraction of polycyclic aromatic compounds from coal.

    PubMed

    Kerst, M; Andersson, J T

    2001-08-01

    Microwave-assisted extraction (MAE) of polycyclic aromatic compounds (PACs) from coal is shown to give the same pattern of compounds as Soxhlet extraction. MAE requires only 10 mL solvent and 10 min extraction time whereas Soxhlet uses 200 mL and takes 24 h. Although the yields were lower, dichloromethane (DCM) was preferred to pyridine, N-methyl-2-pyrrolidone (NMP), and NMP with CS2 because the pattern of the PACs is shown to be independent of solvent and DCM is a much more convenient solvent to work with.

  1. Polycyclic aromatic hydrocarbons, tobacco smoke, and epigenetic remodeling in asthma

    PubMed Central

    Klingbeil, E. C.; Hew, K. M.; Nygaard, U. C.; Nadeau, K. C.

    2014-01-01

    Environmental determinants including aerosolized pollutants such as polycyclic aromatic hydrocarbons (PAHs) and tobacco smoke have been associated with exacerbation and increased incidence of asthma. The influence of aerosolized pollutants on the development of immune dysfunction in asthmatics has been suggested to be mediated through epigenetic remodeling. Genome accessibility and transcription are regulated primarily through DNA methylation, histone modification, and microRNA transcript silencing. Epigenetic remodeling has been shown in studies to be associated with Th2 polarization and associated cytokine and chemokine regulation in the development of asthma. This review will present evidence for the contribution of the aerosolized pollutants PAH and environmental tobacco smoke to epigenetic remodeling in asthma. PMID:24760221

  2. Temperature dependence of infrared bands produced by polycyclic aromatic hydrocarbons

    NASA Astrophysics Data System (ADS)

    Colangeli, L.; Mennella, V.; Bussoletti, E.

    1992-02-01

    The behavior of IR absorption bands with temperature has been examined systematically in the laboratory for three representative polycyclic aromatic hydrocarbon molecules: coronene, chrysene, and 1-methylcoronene. A careful description of both intensity and profile measured for most of the bands is reported. A tentative interpretation of the observed variations is given in terms of extra-molecular effects produced by the anharmonicity of the vibrational energy levels as a function of temperature. These new laboratory data provide an accurate description of the optical properties for representative molecules often used to account for the so-called unidentified infrared bands emitted by astronomical sources.

  3. Surfactant-mediated Biodegradation of Polycyclic Aromatic Hydrocarbons

    PubMed Central

    Li, Jing-Liang; Chen, Bing-Hung

    2009-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are toxic environmental pollutants that are known or suspected carcinogens or mutagens. Bioremediation has been used as a general way to eliminate them from the contaminated sites or aquifers, but their biodegradation is rather limited due to their low bioavailability because of their sparingly soluble nature. Surfactant-mediated biodegradation is a promising alternative. The presence of surfactants can increase the solubility of PAHs and hence potentially increase their bioavailability. However, inconclusive results have been reported on the effects of surfactant on the biodegradation of PAHs. In this work, surfactant-mediated biodegradation of PAHs is reviewed.

  4. Synthesis of condensed phases containing polycyclic aromatic hydrocarbons fullerenes and nanotubes

    DOEpatents

    Reilly, Peter T. A.

    2004-10-19

    The invention relates to methods for producing polycyclic aromatic hydrocarbons, fullerenes, and nanotubes, comprising: a. heating at least one carbon-containing material to form a condensed phase comprising at least one polycyclic aromatic hydrocarbon; b. collecting at least some of the condensed phase; c. reacting the condensed phase to form fullerenes and/or nanotubes.

  5. Examining spatial patterns in polycyclic aromatic compounds measured in stream macroinvertebrates near a small subarctic oil and gas operation.

    PubMed

    Korosi, J B; Eickmeyer, D C; Chin, K S; Palmer, M J; Kimpe, L E; Blais, J M

    2016-03-01

    The Cameron River runs through a small, remote petrochemical development in the Cameron Hills (Northwest Territories, Canada). In order to evaluate the exposure of aquatic biota to contaminants from oil and gas activities, we measured polycyclic aromatic compounds (PACs) in macroinvertebrates collected from sites and tributaries along the Cameron River, including upstream and downstream of the development, and sites located near drilled wells (developed). Macroinvertebrate tissue PAC burdens ranged from 0.2-2.8 μg g(-1) lipid for unsubstituted compounds, and from 4.2-63.2 μg g(-1) lipid for alkylated compounds, relatively low compared to similar studies from more industrialized regions in North America. There was no significant difference in tissue PAC burdens between upstream, downstream, or developed sites (p = 0.12), although alkyl PACs in five out of seven developed sites were higher than the regional average. Petrogenic PACs were dominant in most samples, including alkyl fluorines, alkyl phenanthrene/anthracenes, and alkyl dibenzothiophenes. Minimal changes in PAC composition in macroinvertebrate tissues were detected along the Cameron River, with the exception of the two sites furthest downstream that had high concentrations of C3-C4 naphthalene. Overall, our results suggest that oil and gas development in the Cameron Hills has not resulted in substantial increases in PAC bioaccumulation in stream macroinvertebrates, although the potential that alkyl naphthalenes are being transported downstream from the development warrants further attention.

  6. The formation of Polycyclic Aromatic Hydrocarbons in evolved circumstellar environments

    NASA Astrophysics Data System (ADS)

    Cherchneff, I.

    2011-03-01

    The formation of Polycyclic Aromatic Hydrocarbons in the circumstellar outflows of evolved stars is reviewed, with an emphasis on carbon stars on the Asymptotic Giant Branch. Evidence for PAHs present in their winds is provided by meteoritic studies and recent observations of the Unidentified Infrared bands. We detail the chemical processes leading to the closure of the first aromatic ring as well as the growth mechanisms leading to amorphous carbon grains. Existing studies on PAH formation in evolved stellar envelopes are reviewed and new results for the modelling of the inner wind of the archetype carbon star IRC+10216 are presented. Benzene, C6H6, forms close to the star, as well as water, H2O, as a result of non-equilibrium chemistry induced by the periodic passage of shocks. The growth process of aromatic rings may thus resemble that active in sooting flames due to the presence of radicals like hydroxyl, OH. Finally, we discuss possible formation processes for PAHs and aromatic compounds in the hydrogen-rich R CrB star, V854 Cen, and their implication for the carriers of the Red Emission and the Diffuse Interstellar Bands.

  7. Stereochemistry of bistricyclic aromatic enes and related polycyclic systems.

    PubMed

    Biedermann, P Ulrich; Agranat, Israel

    2014-01-01

    Bistricyclic aromatic enes (BAEs) and related polycyclic systems are a class of molecular materials that display a rich variety of conformations, dynamic stereochemistry and switchable chirality, color, and spectroscopic properties. This is due to the a subtle interplay of the inherent preference for planarity of aromatic systems and the competing necessity of non-planarity due to intramolecular overcrowding in the fjord regions built into the general molecular structure of BAEs. The conformational, dynamic, and spectroscopic properties may be designed and fine-tuned, e.g., by variation of the bridging groups X and Y, the overcrowding in the fjord regions, extensions of the aromatic system, or other modifications of the general BAE structure, based on the fundamental understanding of the structure-property relationships (SPR). The present review provides an analysis of the conformational spaces and the dynamic stereochemistry of overcrowded bistricyclic aromatic enes applying fundamental symmetry considerations. The symmetry analysis presented here allows deeper insight into the conformations, chirality, and the mechanisms of the dynamic stereochemistry, and will be instrumental in future computational studies.

  8. Consensus sediment quality guidelines for polycyclic aromatic hydrocarbon mixtures

    SciTech Connect

    Swartz, R.C.

    1999-04-01

    Sediment quality guidelines (SQGs) for polycyclic aromatic hydrocarbons (PAHs) have been derived from a variety of laboratory, field, and theoretical foundations. They include the screening level concentration, effects ranges-low and -median, equilibrium partitioning concentrations, apparent effects threshold, {Sigma}PAH model, and threshold and probable effects levels. The resolution of controversial differences among the PAH SQGs lies in an understanding of the effects of mixtures. Polycyclic aromatic hydrocarbons virtually always occur in field-collected sediment as a complex mixture of covarying compounds. When expressed as a mixture concentration, that is, total PAH (TPAH), the guidelines form three clusters that were intended in their original derivations to represent threshold (TEC = 290 {micro}g/g organic carbon [OC]), median (MEC = 1,800 {micro}g/g OC), and extreme (EEC = 10,000 {micro}g/g OC) effects concentrations. The TEC/MEC/EEC consensus guidelines provide a unifying synthesis of other SQGs, reflect causal rather than correlative effects, account for mixtures, and predict sediment toxicity and benthic community perturbations at sites of PAH contamination. The TEC offers the most useful SQG because PAH mixtures are unlikely to cause adverse effects on benthic ecosystems below the TEC.

  9. Thermochemical properties and phase behavior of halogenated polycyclic aromatic hydrocarbons.

    PubMed

    Fu, Jinxia; Suuberg, Eric M

    2012-03-01

    Knowledge of vapor pressure of organic pollutants is essential in predicting their fate and transport in the environment. In the present study, the vapor pressures of 12 halogenated polycyclic aromatic compounds (PACs), 9-chlorofluorene, 2,7-dichlorofluorene, 2-bromofluorene, 9-bromofluorene, 2,7-dibromofluorene, 2-bromoanthracene, 9-chlorophenanthrene, 9-bromophenanthrene, 9,10-dibromophenanthrene, 1-chloropyrene, 7-bromobenz[a]anthracene, and 6,12-dibromochrysene, were measured using the Knudsen effusion method over the temperature range of 301 to 464 K. Enthalpies and entropies of sublimation of these compounds were determined via application of the Clausius-Clapeyron equation. The data were also compared with earlier published literature values to study the influence of halogen substitution on vapor pressure of PACs. As expected, the halogen substitution decreases vapor pressure compared with parent compounds but does not necessarily increase the enthalpy of sublimation. Furthermore, the decrease of vapor pressure also depends on the substitution position and the substituted halogen, and the di-substitution of chlorine and/or bromine decreases the vapor pressure compared with single halogen-substituted polycyclic aromatic hydrocarbons. In addition, the enthalpy of fusion and melting temperature of these 12 PACs were determined using differential scanning calorimetry and melting point analysis.

  10. Atmospheric chlorinated polycyclic aromatic hydrocarbons in East Asia.

    PubMed

    Kakimoto, Kensaku; Nagayoshi, Haruna; Konishi, Yoshimasa; Kajimura, Keiji; Ohura, Takeshi; Hayakawa, Kazuichi; Toriba, Akira

    2014-09-01

    This study estimates atmospheric concentrations of chlorinated polycyclic aromatic hydrocarbons (ClPAHs) and polycyclic aromatic hydrocarbons (PAHs) in East Asia using a Gas Chromatograph with High Resolution Mass Spectrometer (GC-HRMS). ClPAHs are ubiquitously generated from PAHs through substitution, and some ClPAHs show higher aryl hydrocarbon receptor (AhR)-mediated activities than their parent PAHs. Atmospheric particles were collected using a high-volume air sampler equipped with a quartz-fiber filter. We determined the ClPAH concentrations of atmospheric particles collected in Japan (Sapporo, Sagamihara, Kanazawa, and Kitakyushu), Korea (Busan), and China (Beijing). The concentrations of ClPAHs were highest in the winter Beijing sample, where the total mean concentration was approximately 15-70 times higher than in the winter samples from Japan and Korea. The concentrations of Σ19ClPAHs and Σ9PAHs were significantly correlated in the Kanazawa and the Busan samples. This indicates that within those cities ClPAHs and PAHs share the same origin, implying direct chlorination of parent PAHs. Toxic equivalent concentrations (TEQs) of the total ClPAHs and PAHs were lowest in Kanazawa in the summer, reaching 1.18 and 2610fg-TEQm(-3) respectively, and highest in Beijing in the winter, reaching 627 and 4240000fg-TEQm(-3) respectively.

  11. Assessment of polycyclic aromatic hydrocarbons (PAHs) pollution in soil of suburban areas in Tianjin, China.

    PubMed

    Lv, Jungang; Shi, Rongguang; Cai, Yanming; Liu, Yong

    2010-07-01

    Soil contamination with polycyclic aromatic hydrocarbons is an increasing problem and has aroused more and more concern in many countries, including China. In this study, representative soil samples (n = 87) of suburban areas in Tianjin (Xiqing, Dongli, Jinnan, Beichen) were evaluated for 16 polycyclic aromatic hydrocarbons. Surface soil samples were air-dried and sieved. Microwave assisted extraction was used for polycyclic aromatic hydrocarbons preparation prior to analysis with gas chromatography-mass spectrometry. The total concentrations of tested polycyclic aromatic hydrocarbons in Xiqing, Dongli, Jinnan, Beichen ranged in 58.5-2,748.3, 36.1-6,734.7, 58.5-4,502.5, 29.7-852.5 ng/g and the averages of total concentration of polycyclic aromatic hydrocarbons were 600.5, 933.6, 640.8, 257.3 ng/g, respectively. Spatial variation of polycyclic aromatic hydrocarbons in soil was illustrated; Pollution status and comparison to other cities were also investigated. Serious polycyclic aromatic hydrocarbons soil pollution was found in Dongli district, on the contrary, Bap in most sites in Beichen did not exceed relative standards and most sites in Beichen should be classified as non-contaminated soil. Principal component analysis was used to identify the possible sources of different districts. It turned out that coal combustion still was the most important sources in three districts except Beichen. Coking, traffic, cooking, biomass combustion also accounted for polycyclic aromatic hydrocarbons pollution to certain extent in different districts. These data can be further used to assess the health risk associated with soils polluted with polycyclic aromatic hydrocarbons and help local government find proper way to reduce polycyclic aromatic hydrocarbons pollution in soils.

  12. Polycyclic Aromatic Hydrocarbons as Plausible Prebiotic Membrane Components

    NASA Astrophysics Data System (ADS)

    Groen, Joost; Deamer, David W.; Kros, Alexander; Ehrenfreund, Pascale

    2012-08-01

    Aromatic molecules delivered to the young Earth during the heavy bombardment phase in the early history of our solar system were likely to be among the most abundant and stable organic compounds available. The Aromatic World hypothesis suggests that aromatic molecules might function as container elements, energy transduction elements and templating genetic components for early life forms. To investigate the possible role of aromatic molecules as container elements, we incorporated different polycyclic aromatic hydrocarbons (PAH) in the membranes of fatty acid vesicles. The goal was to determine whether PAH could function as a stabilizing agent, similar to the role that cholesterol plays in membranes today. We studied vesicle size distribution, critical vesicle concentration and permeability of the bilayers using C6-C10 fatty acids mixed with amphiphilic PAH derivatives such as 1-hydroxypyrene, 9-anthracene carboxylic acid and 1,4 chrysene quinone. Dynamic Light Scattering (DLS) spectroscopy was used to measure the size distribution of vesicles and incorporation of PAH species was established by phase-contrast and epifluorescence microscopy. We employed conductimetric titration to determine the minimal concentration at which fatty acids could form stable vesicles in the presence of PAHs. We found that oxidized PAH derivatives can be incorporated into decanoic acid (DA) vesicle bilayers in mole ratios up to 1:10 (PAH:DA). Vesicle size distribution and critical vesicle concentration were largely unaffected by PAH incorporation, but 1-hydroxypyrene and 9-anthracene carboxylic acid lowered the permeability of fatty acid bilayers to small solutes up to 4-fold. These data represent the first indication of a cholesterol-like stabilizing effect of oxidized PAH derivatives in a simulated prebiotic membrane.

  13. Polycyclic aromatic hydrocarbons as plausible prebiotic membrane components.

    PubMed

    Groen, Joost; Deamer, David W; Kros, Alexander; Ehrenfreund, Pascale

    2012-08-01

    Aromatic molecules delivered to the young Earth during the heavy bombardment phase in the early history of our solar system were likely to be among the most abundant and stable organic compounds available. The Aromatic World hypothesis suggests that aromatic molecules might function as container elements, energy transduction elements and templating genetic components for early life forms. To investigate the possible role of aromatic molecules as container elements, we incorporated different polycyclic aromatic hydrocarbons (PAH) in the membranes of fatty acid vesicles. The goal was to determine whether PAH could function as a stabilizing agent, similar to the role that cholesterol plays in membranes today. We studied vesicle size distribution, critical vesicle concentration and permeability of the bilayers using C(6)-C(10) fatty acids mixed with amphiphilic PAH derivatives such as 1-hydroxypyrene, 9-anthracene carboxylic acid and 1,4 chrysene quinone. Dynamic Light Scattering (DLS) spectroscopy was used to measure the size distribution of vesicles and incorporation of PAH species was established by phase-contrast and epifluorescence microscopy. We employed conductimetric titration to determine the minimal concentration at which fatty acids could form stable vesicles in the presence of PAHs. We found that oxidized PAH derivatives can be incorporated into decanoic acid (DA) vesicle bilayers in mole ratios up to 1:10 (PAH:DA). Vesicle size distribution and critical vesicle concentration were largely unaffected by PAH incorporation, but 1-hydroxypyrene and 9-anthracene carboxylic acid lowered the permeability of fatty acid bilayers to small solutes up to 4-fold. These data represent the first indication of a cholesterol-like stabilizing effect of oxidized PAH derivatives in a simulated prebiotic membrane.

  14. Thermodiffusion of polycyclic aromatic hydrocarbons in binary mixtures

    NASA Astrophysics Data System (ADS)

    Hashmi, Sara M.; Senthilnathan, Sid; Firoozabadi, Abbas

    2016-11-01

    Thermodiffusion in liquid mixtures may explain some counter-intuitive but naturally occurring phenomena such as hydrocarbon reservoirs with heavier component(s) stratified on top of lighter ones. However, beyond benchmark systems, systematic measurements of thermodiffusion in binary organic mixtures are lacking. We use an optical beam deflection apparatus to simultaneously probe Fickian and thermal diffusion in binary solution mixtures of polycyclic aromatic hydrocarbons dissolved in alkanes, and measure both Fickian diffusion D and the Soret coefficient ST, and then obtain the thermodiffusion coefficient DT. In a series of nine binary mixtures, we vary both the size of the aromatic compound from two to four rings, as well as the length of the alkane chain from 6 to 16 carbons. To probe the effect of increasing ring size, we include a 6-ringed aromatic compound, coronene, and toluene as a solvent, due to the insolubility of coronene in alkanes. Our results suggest that Fickian diffusion increases with the inverse of solvent viscosity and also with decreasing molecular weight of the solute. While both of these trends match our intuition, the behavior of ST and DT is more complicated. We find that ST and DT increase with the solute molecular weight when the solvent is held fixed and that the impact of solute ring size is higher in shorter chain alkane solvents.

  15. Xenoestrogenic gene expression: structural features of active polycyclic aromatic hydrocarbons.

    PubMed

    Schultz, T Wayne; Sinks, Glendon D

    2002-04-01

    Estrogenicity was assessed using the Saccharomyces cerevisiae-based Lac-Z reporter assay and was reported as the logarithm of the inverse of the 50% molar beta-galactosidase activity (log[EC50(-1)]). In an effort to quantify the relationship between molecular structure of polycyclic aromatic hydrocarbons (PAHs) and estrogenic gene expression, a series of PAHs were evaluated. With noted exceptions, the results of these studies indicate that the initial two-dimensional structural warning for estrogenicity, the superpositioning of a hydroxylated aromatic system on the phenolic A-ring of 17-beta-estradiol, can be extended to the PAHs. This two-dimensional-alignment criterion correctly identified estrogenicity of 22 of the 29 PAHs evaluated. Moreover, the estrogenic potency of these compounds was directly related to the size of the hydrophobic backbone. The seven compounds classified incorrectly by this structural feature were either dihydroxylated naphthalenes or aromatic nitrogen-heterocyclic compounds; all such compounds were false positives. Results with dihydroxylated naphthalenes reveal derivatives that were nonestrogenic when superimposed on the phenolic A-ring of 17-beta-estradiol had the second hydroxyl group in the position of the C-ring or were catechol-like in structure. Structural alerts for nitrogen-heterocyclic compounds must take into account the position of the hydroxyl group and the in-ring nitrogen atom; compounds with the hydroxyl group and nitrogen atom involved with the same ring were observed to be nonactive.

  16. Secondary organic aerosol from polycyclic aromatic hydrocarbons in Southeast Texas

    NASA Astrophysics Data System (ADS)

    Zhang, Hongliang; Ying, Qi

    2012-08-01

    Recent chamber studies show that low-volatility gas phase precursors such as polycyclic aromatic hydrocarbons (PAHs) can be a significant source of secondary organic aerosol (SOA). In this work, formation of SOA from the photo-oxidation products of PAHs is added to the SOA modeling framework of the Community Multiscale Air Quality (CMAQ) model to determine the regional distribution of SOA products from PAHs (PAH-SOA) and the contributions from sources in Southeast Texas during the Texas Air Quality Study 2006 (TexAQS 2006). Results show that PAHs released from anthropogenic sources can produce SOA mass as much as 10% of that from the traditional light aromatics or approximately 4% of total anthropogenic SOA. In areas under the influence of wildfire emissions, the amount of PAH-SOA can be as much as 50% of the SOA from light aromatics. A source-oriented modeling framework is adopted to determine the major sources of PAH-SOA by tracking the emitted PAHs and their oxidation products in the gas and aerosol phases from different sources separately. Among the eight sources (vehicles, solvent utilization, residential wood, industries, natural gas combustion, coal combustion, wildfire and other sources) that are tracked in the model, wildfire, vehicles, solvent and industries are the major sources of PAH-SOA. Coal and natural gas combustion appear to be less important in terms of their contributions to PAH-SOA.

  17. Historical Profiles of Polycyclic Aromatic Hydrocarbons (PAHs) in Marine Sediment Cores from Northwest Spain.

    PubMed

    Pérez-Fernández, Begoña; Viñas, Lucía; Bargiela, Jesica

    2016-11-01

    The northwest coast of Spain is characterized by an irregular coastline rich in marine life and with the highest mussel production in Europe. Taking this into account, the characterization of the pollution levels and the sources involved appear necessary. Not only were parent Polycyclic Aromatic Hydrocarbons (PAHs) analysed but also their alkylated homologues. In total, 35 compounds were analyzed in 5 sediment cores. Sediments were collected using a box core dredge and extracted by (Pressurized Liquid Extraction) whilst the quantification of PAHs was performed using gas chromatography coupled to mass spectrometry (GC-MS). The total concentration detected varied from 49.6 to 2489 ng g(-1) dry weight (d.w.) of which parent PAHs ranged from 44.5 to 2254 ng g(-1) d.w. and alkylated PAHs varied from 5.04 to 317 ng g(-1) d.w. Temporal and spatial evolution were outlined and pollution sources were identified along with a possible correlation between this pollution and local history and industry. Most of the PAHs from the superficial samples have a biomass and coal combustion profile, and some specific, localized events are reflected in the total PAH concentration evolution. Moreover, the study of the deepest layers of the sampled cores provides a baseline to develop background concentration values that will help in future sediment quality assessment.

  18. Polar metabolites of polycyclic aromatic compounds from fungi are potential soil and groundwater contaminants.

    PubMed

    Boll, Esther S; Johnsen, Anders R; Christensen, Jan H

    2015-01-01

    This study investigated the sorption to soil of water-soluble metabolites from polycyclic aromatic compounds (PACs). The soil fungus Cunninghamella elegans was used to produce PAC metabolites from two un-substituted PACs (phenanthrene, pyrene), three alkyl-substituted PACs (2-methylnaphthalene, 1-methylphenanthrene, 1-methylpyrene), and one sulfur-containing heterocyclic PAC (dibenzothiophene). Fifty-eight metabolites were tentatively identified; metabolites from the un-substituted PACs were hydroxylated and sulfate conjugated, whereas metabolites from alkyl-substituted PACs were sulfate conjugated and either hydroxylated or oxidized to carboxylic acids at the methyl group. The metabolism of the sulfur-containing heterocyclic PAC resulted in sulfate conjugates. The sorption of the PAC metabolites to three soils was determined using a batch equilibrium method, and partition coefficients (Kd's) were calculated for fourteen representative metabolites. Sulfate conjugated metabolites displayed Kd's below 70 whereas the metabolites with both a sulfate and a carboxylic acid group had Kd's below 2.8. The low Kd's of water-soluble PAC metabolites indicate high mobility in soil and a potential for leaching to surface- and groundwaters. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Biocatalytic oxidation of polycyclic aromatic hydrocarbons by hemoglobin and hydrogen peroxide.

    PubMed

    Ortiz-Leon, M; Velasco, L; Vazquez-Duhalt, R

    1995-10-24

    Hemoglobin is able to oxidize polycyclic aromatic hydrocarbons, PAH's, in presence of hydrogen peroxide. Among 12 aromatic compounds tested, six were oxidized; anthracene, carbazole, dibenzothiophene, fluorene, 9-hexylanthracene and pyrene. The products were identified as aromatic ketones and sulfoxides. Effect of organic solvent concentration and hemoglobin stability were determined.

  20. Toxicological profile for polycyclic aromatic hydrocarbons. Final report

    SciTech Connect

    Not Available

    1990-12-01

    The ATSDR Toxicological Profile for Polycyclic Aromatic Hydrocarbons (PAHs): Acenaphthene, Acenaphthylene, Anthracene, Benzo(a)anthracene, Benzo(a)pyrene, Benzo(b)fluoranthene, Benzo(g,h,i)perylene, Benzo(k)fluoranthene, Chrysene, Dibenzo(a,h)anthracene, Fluoranthene, Fluorene, Indeno(1,2,3-cd)pyrene, Phenanthrene, Pyrene is intended to characterize succinctly the toxicological and health effects information for the substance. It identifies and reviews the key literature that describes the substance's toxicological properties. Other literature is presented but described in less detail. The profile begins with a public health statement, which describes in nontechnical language the substance's relevant toxicological properties. The adequacy of information to determine the substance's health effects is described. Research gaps in nontoxic and health effects information are described. Research gaps that are of significance to the protection of public health will be identified in a separate effort. The focus of the document is on health and toxicological information.

  1. Determination of polycyclic aromatic hydrocarbons in roasted coffee

    PubMed Central

    JIMENEZ, ANGELICA; ADISA, AFOLABI; WOODHAM, CARA; SALEH, MAHMOUD

    2016-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are suspected to be carcinogenic and mutagenic. This study describes the presence of PAHs in light, medium and dark roasted coffee including instant and decaffeinated brands. Total PAHs concentration was related to the degree of roasting with light roasted coffee showing the least and dark roasted coffee showing the highest level. Both instant and decaffeinated coffee brand showed lower levels of PAHs. Naphthalene, acenaphthylene, pyrene and chrysene were the most abundant individual isomers. The concentrations ranged from 0 to 561 ng g−1 for naphthalene, 0 to 512 ng g−1 for acenaphthylene, 60 to 459 ng g−1 for pyrene and 56 to 371 ng g−1 for chrysene. Thus, roasting conditions should be controlled to avoid the formation of PAHs due to their suspected carcinogenic and mutagenic properties. PMID:25190557

  2. Accumulation of polycyclic aromatic hydrocarbons in acid sensitive lakes

    SciTech Connect

    Furlong, E.T.; Cessar, L.R.; Hites, R.A. )

    1987-11-01

    Polycyclic aromatic hydrocarbon concentrations and fluxes were measured in {sup 210}Pb dated sediment cores taken from nine lakes in four regions identified as susceptible to acidification. Calculated PAH accumulations were compared with historic S emissions, accumulation of sedimentary S, and anthropogenic metal accumulations to determine if PAH could be used as an indicator of combustion-derived sulfate deposition. Comparisons between regions indicated that the Adirondacks have a significantly higher burden of PAH than do northern New England, the northern Great Lakes States, and northern Florida. This difference likely results from significant upwind PAH sources to the Adirondack lakes. Detailed investigation of the largest lake in the study set, Big Moose Lake, indicates that PAH may serve as conservative, combustion indicators in large lakes. In this lake, PAH fluxes and concentrations were significantly correlated with historical S emission rates. These data suggest that PAH measured in sediment cores from large lakes can serve as indicators of past combustion production deposition.

  3. Accumulation of polycyclic aromatic hydrocarbons in acid sensitive lakes

    NASA Astrophysics Data System (ADS)

    Furlong, Edward T.; Cessar, Linda Roll; Hites, Ronald A.

    1987-11-01

    Polycyclic aromatic hydrocarbon concentrations and fluxes were measured in 210Pb dated sediment cores taken from nine lakes in four regions identified as susceptible to acidification. Calculated PAH accumulations were compared with historic S emissions, accumulation of sedimentary S and anthropogenic metal accumulations to determine if PAH could be used as an indicator of combustion-derived sulfate deposition. Comparisons between regions indicated that the Adirondacks have a significantly higher burden of PAH than do northern New England, the northern Great Lakes States and northern Florida. This difference likely results from significant upwind PAH sources to the Adirondack lakes. Detailed investigation of the largest lake in the study set, Big Moose Lake, indicates that PAH may serve as conservative, combustion indicators in large lakes. In this lake, PAH fluxes and concentrations were significantly correlated with historical S emission rates. These data suggest that PAH measured in sediment cores from large lakes can serve as indicators of past combustion product deposition.

  4. Polycyclic Aromatic Hydrocarbons and the Diffuse Interstellar Bands: a Survey

    NASA Technical Reports Server (NTRS)

    Salama, F.; Galazutdinov, G. A.; Krelowski, J.; Allamandola, L. J.; Musaev, F. A.; DeVincenzi, Donald L. (Technical Monitor)

    1999-01-01

    We discuss the proposal relating the origin of some of the diffuse interstellar bands (DIBs) to neutral and ionized polycyclic aromatic hydrocarbons (PAHs) present in interstellar clouds. Laboratory spectra of several PAHs, isolated at low temperature in inert gas matrices, are compared with an extensive set of astronomical spectra of reddened, early type stars. From this comparison, it is concluded that PAN ions are good candidates to explain some of the DIBs. Unambiguous assignments are difficult, however, due to the shift in wavelengths and the band broadening induced in the laboratory spectra by the solid matrix. Definitive band assignments and, ultimately, the test of the of the proposal that PAH ions carry some of the DIB must await the availability of gas-phase measurements in the laboratory. The present assessment offers a guideline for future laboratory experiments by allowing the preselection of promising PAH molecules to be studied in jet expansions.

  5. Determination of polycyclic aromatic hydrocarbons in roasted coffee.

    PubMed

    Jimenez, Angelica; Adisa, Afolabi; Woodham, Cara; Saleh, Mahmoud

    2014-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are suspected to be carcinogenic and mutagenic. This study describes the presence of PAHs in light, medium and dark roasted coffee including instant and decaffeinated brands. Total PAHs concentration was related to the degree of roasting with light roasted coffee showing the least and dark roasted coffee showing the highest level. Both instant and decaffeinated coffee brand showed lower levels of PAHs. Naphthalene, acenaphthylene, pyrene and chrysene were the most abundant individual isomers. The concentrations ranged from 0 to 561 ng g(-1) for naphthalene, 0 to 512 ng g(-1) for acenaphthylene, 60 to 459 ng g(-1) for pyrene and 56 to 371 ng g(-1) for chrysene. Thus, roasting conditions should be controlled to avoid the formation of PAHs due to their suspected carcinogenic and mutagenic properties.

  6. Phototoxicity of polycyclic aromatic hydrocarbons at varying light intensities

    SciTech Connect

    Ankley, G.T.; Phipps, G.L.; Mattson, V.R.; Erickson, R.J.; Kosian, P.A.; Cox, J.S.; Sheedy, B.R.; Mount, D.R.

    1994-12-31

    Conceptual models suggest that the toxicity of photoactivated polycyclic aromatic hydrocarbons (PAHs) should be a function both of chemical (PAH) dose, and intensity of the ultraviolet (UV) light to which the organism is exposed (photon dose). However, there have been no systematic studies with aquatic organisms to quantify the relationship between PAH dose and UV intensity in producing phototoxicity. In these studies, oligochaetes (Lumbriculus variegatus) were exposed, via the water, to multiple concentrations of individual PAHs known to be photoactivated (fluoranthene, pyrene, anthracene), and then placed under UV light of three different intensities. The resultant phototoxicity clearly was a function both of PAH dose and light intensity. A joint toxicity model relating toxicity to PAH concentrations and light intensity will be presented.

  7. Polycyclic aromatic hydrocarbons in solid residues from waste incineration.

    PubMed

    Wheatley, A D; Sadhra, S

    2004-05-01

    Polycyclic aromatic hydrocarbons (PAH) levels in solid residues from clinical waste incineration were measured using HPLC with fluorescence detection. PAH mass emission rates and emission rates as a function of waste burned are also reported. For bottom ash, PAH levels and physical properties were found to be quite consistent. Levels of high molecular mass PAHs were comparable to levels previously reported in the literature when adjusted for differences in sample preparation techniques. However, levels of low molecular mass PAHs were considerably elevated in this study. Possible reasons for this finding include the composition of the waste, combustion conditions and methods of sample preparation. In contrast, no PAHs were found in fly ash, an unexpected finding which is probably attributable to matrix effects resulting from a surfeit of lime in the fly ash. Factors effecting the partitioning of PAHs and their environmental fate are also discussed.

  8. Polycyclic aromatic hydrocarbons - Primitive pigment systems in the prebiotic environment

    NASA Technical Reports Server (NTRS)

    Deamer, D. W.

    1992-01-01

    The chemical evolution of meteoritic organics in the primitive earth is examined experimentally with attention given to the photochemical effects of hydrocarbon/water mixtures. Also addressed are the generation of amphiphilic products by photochemical reactions and the transduction of light energy into potentially useful forms. Polycyclic aromatic hydrocarbons (PAHs) absorb light and exist in carbonaceous chondrites; PAHs are therefore examined as primitive pigments by means of salt solutions with pyrene, fluoranthene, and pyrene derivatives with hexadecane. The hexadecane undergoes photochemical oxidation and yields long-chain amphiphiles with oxygen supplied by water, and acid pH shifts also occur. PAHs are also tested in lipid bilayer membranes to examine light-energy transduction. Protons are found to accumulate within the membrane-bounded volume to form proton gradients, and this reaction is theorized to be a good model of primitive photochemical reactions that related to the transduction of light energy into useable forms.

  9. Polycyclic aromatic hydrocarbons in cereal products on the Turkish market.

    PubMed

    Kacmaz, Sibel

    2016-09-01

    The contamination level of four EU marker polycyclic aromatic hydrocarbons (PAHs) in some cereal-derived products was surveyed in this study. Thirty-eight samples, 20 bread and 18 breakfast cereals, were purchased from retail shops and local markets of East Black sea region in Turkey. The samples were analysed for four EU marker PAHs, using ultrasonic extraction, solid-phase extraction (SPE) clean up and stable-isotope dilution gas chromatography with mass-spectrometric (GC/MS) detection. The method was validated with the parameters linearity, accuracy, precision, limit of detection (LOD), limit of quantitation (LOQ) and uncertainty. Total content of the four PAHs in bread varied from 0.19 to 0.46 µg kg(-1) and in breakfast cereals from 0.10 to 0.87 µg kg(-1).

  10. Polycyclic aromatic hydrocarbons - Primitive pigment systems in the prebiotic environment

    NASA Technical Reports Server (NTRS)

    Deamer, D. W.

    1992-01-01

    The chemical evolution of meteoritic organics in the primitive earth is examined experimentally with attention given to the photochemical effects of hydrocarbon/water mixtures. Also addressed are the generation of amphiphilic products by photochemical reactions and the transduction of light energy into potentially useful forms. Polycyclic aromatic hydrocarbons (PAHs) absorb light and exist in carbonaceous chondrites; PAHs are therefore examined as primitive pigments by means of salt solutions with pyrene, fluoranthene, and pyrene derivatives with hexadecane. The hexadecane undergoes photochemical oxidation and yields long-chain amphiphiles with oxygen supplied by water, and acid pH shifts also occur. PAHs are also tested in lipid bilayer membranes to examine light-energy transduction. Protons are found to accumulate within the membrane-bounded volume to form proton gradients, and this reaction is theorized to be a good model of primitive photochemical reactions that related to the transduction of light energy into useable forms.

  11. Gas and Particulate Sampling of Airborne Polycyclic Aromatic Compounds

    SciTech Connect

    Lane, D.A.; Gundel, L.A.

    1995-10-01

    The denuder surfaces of the gas and particle (GAP) sampler (developed at the Atmospheric Environment Service of Environment Canada) have been modified by coating with XAD-4 resin, using techniques developed at Lawrence Berkeley National Laboratory (LBNL) for the lower capacity integrated organic vapor/particle sampler (IOVPS). The resulting high capacity integrated organic gas and particle sampler (IOGAPS) has been operated in ambient air at 16.7 L min{sup -1} for a 24-hour period in Berkeley, California, USA. Simultaneous measurements were made at the same collection rate with a conventional sampler that used a filter followed by two sorbent beds. Gas and particle partition measurements were determined for 13 polycyclic aromatic hydrocarbons (PAH) ranging from 2-ring to 6-ring species. The IOGAPS indicated a higher particle fraction of these compounds than did the conventional sampler, suggesting that the conventional sampler suffered from 'blow-off' losses from the particles collected on the filter.

  12. Simulated transport of polycyclic aromatic hydrocarbons in artificial streams

    SciTech Connect

    Bartell, S.M.; Landrum, P.F.; Giesy, J.P.; Leversee, G.J.

    1981-01-01

    A model was constructed to predict the pattern of flow and accumulation of three polycyclic aromatic hydrocarbons (PAH) (anthracene, naphthalene, and benzo(a)pyrene) in artificial streams located on the Savannah River Plant near Aiken, South Carolina. Predictions were based upon the premise that the fundamental chemistry of individual PAH contains useful information for predictive purposes. Model processes included volatilization, photolysis, sorption to sediments and particulates, and net accumulation by biota. Simulations of anthracene transport were compared to results of an experiment conducted in the streams. The model realistically predicted the concentration of dissolved anthracene through time and space. Photolytic degradation appeared to be a major pathway of anthracene flux from the streams.

  13. Polycyclic aromatic hydrocarbons' formation and occurrence in processed food.

    PubMed

    Singh, Lochan; Varshney, Jay G; Agarwal, Tripti

    2016-05-15

    Polycyclic aromatic hydrocarbons (PAHs) emerged as an important contaminant group in a gamut of processed food groups like dairy, nuts, herbs, beverages, meat products etc. Different cooking processes and processing techniques like roasting, barbecuing, grilling, smoking, heating, drying, baking, ohmic-infrared cooking etc. contribute towards its formation. The level of PAHs depends on factors like distance from heat source, fuel used, level of processing, cooking durations and methods, whereas processes like reuse, conching, concentration, crushing and storage enhance the amount of PAHs in some food items. This review paper provides insight into the impact of dietary intake of PAHs, its levels and formation mechanism in processed food items and possible interventions for prevention and reduction of the PAHs contamination. The gaps and future prospects have also been assessed.

  14. Accumulation of polycyclic aromatic hydrocarbons (PAHs) in an urban snowpack.

    PubMed

    Boom, A; Marsalek, J

    1988-08-01

    Accumulations of polycyclic aromatic hydrocarbons in a snowpack were studied in an industrial urban area with numerous anthropogenic sources of PAHs. Average PAH loadings stored in the snowpack were determined, plotted on a map of the study area, and arenal distribution approximated by isoloading contours. The loading contours exhibited a marked elongation in the direction of prevailing winds. The unit-area deposition rates observed in the study area exceeded the typical rates reported for other urban areas, and were the highest immediately downwind of a steel plant. PAH levels in snowmelt were well below the freshwater aquatic life toxicity criteria, but exceeded both the WHO drinking water standard and the U.S. EPA carcinogenic criteria at the 10(-5) risk level.

  15. Emission factors for polycyclic aromatic hydrocarbons from biomass burning

    SciTech Connect

    Jenkins, B.M.; Jones, A.D.; Turn, S.Q.; Williams, R.B.

    1996-08-01

    Emission factors for 19 polycyclic aromatic hydrocarbons were measured during wind tunnel simulations of open burning for agricultural and forest biomass fuels including cereal grasses, agricultural tree prunings, and fir and pine wood (slash). Yields of total PAH varied from 5 to 683 mg kg{sup -1} depending principally on burning conditions and to a lesser extent on fuel type. Barley straw and wheat straw loaded at 400-500 g m{sup -2} emitted much higher levels of PAH, including benzo[a]pyrene, than other cereal and wood fuel types burning under more robust conditions. As anticipated, total PAH emission rates increased with increasing particulate matter emission rates and with declining combustion efficiency. 20 refs., 2 figs., 6 tabs.

  16. Transport of Polycyclic Aromatic Hydrocarbons in Unsaturated Porous Media

    NASA Astrophysics Data System (ADS)

    Chahal, Maninder; Flury, Markus

    2016-04-01

    Polycyclic aromatic hydrocarbons (PAHs) are complex organic molecules containing 2 or more fused benzene rings. Being hydrophobic and non-polar, PAHs tend to partition to the organic matter in the soil from bulk aqueous phase. Though transport of these contaminants has been well studied in saturated environment, interactive mechanisms of these fluorescent compounds in unsaturated (identified by presence of air-water interface) porous media is still not well understood. We studied is the transport of fluoranthene in unsaturated porous media as facilitated by moving air-water interfaces. Confocal microscopy was used to visualize the interactions of fluoranthene particles in a glass channel packed with quartz glass beads. The packed glass channel was used to mimic a porous media and effects of an advancing and receding capillary fringe on the detachment of fluoranthene.

  17. Polycyclic aromatic hydrocarbon removal from water by natural fiber sorption.

    PubMed

    Khan, Eakalak; Khaodhir, Sutha; Rotwiron, Paritta

    2007-08-01

    The use of two natural sorbents, kapok and cattail fibers, were investigated for polycyclic aromatic hydrocarbon (PAH) removal from water. Naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, and fluoranthene were the PAHs studied. For comparative purposes, a commercial polyester fiber sorbent was included in the investigation. The PAH sorption and retention capabilities of the three fibers were determined through batch and continuous-flow experiments under non-competitive and competitive conditions. In the batch experiments, cattail fiber was the most effective sorbent. Kapok fiber provided the lowest PAH retention, while cattail fiber had slightly less PAH retention than polyester fiber. When two PAHs were present in the same system, a competitive effect on the much less hydrophobic PAH was observed. Similar results were obtained in the column experiments, except that polyester fiber performed much poorer on naphthalene. Cattail fiber is a promising sorbent for treating PAH-contaminated water, such as urban runoff.

  18. Sequential extraction of polycyclic aromatic hydrocarbons using subcritical water.

    PubMed

    Latawiec, Agnieszka E; Reid, Brian J

    2010-02-01

    A rapid sequential subcritical (superheated) water extraction method for polycyclic aromatic hydrocarbons (PAHs) in contaminated soil and sediment is presented. Decreasing the polarity of water by successive increase of the extraction temperature from 50 degrees C to 200 degrees C at the moderate pressure (10.3MPa) enabled selective, non-exhaustive extractions to be performed. Concurrent with increasing temperatures to 150 degrees C there was an increase in PAH extraction efficiencies. For the majority of determinations no significant differences between extractions at 150 degrees C and 200 degrees C were observed. Varied extraction efficiencies of PAHs at the same extraction conditions reflected dissimilarities between environmental matrices investigated. Selective subcritical water extraction of PAHs was proportional to their octanol-water partition coefficients. This technique may be applicable in evaluation of risks associated with PAH contaminated sites and in assessments of their bioremediation potential.

  19. Destruction and survival of polycyclic aromatic hydrocarbons in active galaxies

    NASA Technical Reports Server (NTRS)

    Voit, G. M.

    1992-01-01

    Infrared spectra of dusty galactic environments often contain emission features attributed to polycyclic aromatic hydrocarbons or PAHs, which can be considered to be very small grains or very large molecules. Although IR spectra of starburst galaxies almost always show these emission features, similar spectra of active galaxies are usually featureless. Even in those active galaxies that do exhibit PAH emission, the PAHs still appear to be eradicated from the nuclear region. This dichotomy suggests that PAHs are destroyed by the intense hard radiation field from an AGN. Laboratory experiments show that certain PAHs are, in fact, so effectively destroyed by individual EUV and X-ray photons that they cannot survive even at kiloparsec distances from active nuclei. Regions within active galaxies that do show PAH emission must therefore be shielded from the central X-ray source by a substantial column density of X-ray absorbing gas.

  20. Polycyclic aromatic hydrocarbons in sediments of China Sea.

    PubMed

    Li, Yanxia; Duan, Xiaoyong

    2015-10-01

    Increasing pollution pressures were placed in the coastal and estuarine ecosystems in China because of the elevated pollutants discharged from various sources. Polycyclic aromatic hydrocarbons (PAHs) in the environment were closely linked to human activities, which have been intensively studied for their geochemical interest as markers. In this review, the status of PAH contamination in China Sea was assessed by comprehensive reviews of the concentrations, sources, and fates of PAHs in sediments of China Sea. PAH concentrations in China Sea sediments decreased from north to south due to the higher emissions in North China. Atmosphere was probably the main carrier of PAHs in the north due to the higher contents of atmospheric fine particles and higher wind speeds. However, riverine inputs were probably the most important sources of PAHs in the coastal sediments of South China due to higher rainfall.

  1. Health risks of residential exposure to polycyclic aromatic hydrocarbons.

    PubMed

    Brender, Jean D; Pichette, Janet L; Suarez, Lucina; Hendricks, Katherine A; Holt, Mandy

    2003-02-01

    A disease prevalence study and follow-up health surveillance were conducted among residents of an African-American community situated at the site of a former creosote wood-treatment facility contaminated with polycyclic aromatic hydrocarbons. Household interviews were conducted among 214 residents living around the hazardous waste site (target population) and 212 comparison residents in a neighborhood 2.4 km away from the site. Target area residents reported a higher prevalence of skin rashes than comparison residents (relative risk [RR] = 5.7; 95% confidence interval [CI] = 3.0, 10.9). The prevalence of reported rashes increased with increasing levels of anthracene detected in yards (test for linear trend, p = 0.02). With adjustment for environmental worry, reports of chronic bronchitis and difficulties becoming pregnant did not differ significantly between target and comparison residents (p > 0.05).

  2. Heterogeneous ozonation kinetics of polycyclic aromatic hydrocarbons on organic films

    NASA Astrophysics Data System (ADS)

    Kahan, T. F.; Kwamena, N.-O. A.; Donaldson, D. J.

    The room temperature heterogeneous reaction rates of gas-phase ozone with naphthalene, anthracene, fluoranthene, phenanthrene, pyrene, and benzo[ a]pyrene were measured over a range of ozone concentrations from 3.5×10 14 to 2.3×10 16 molec. cm -3. The polycyclic aromatic hydrocarbons (PAHs) were dissolved in organic mixtures composed of octanol or decanol along with proxies for compounds known to be present in "urban grime" films. In all cases, the reaction kinetics were well-described by the Langmuir-Hinshelwood mechanism, which suggests a surface reaction. The adsorption of PAHs to the air-organic interface was confirmed by an adsorption isotherm of anthracene. The presence of the additional organic compounds generally did not affect the reaction rates; however, unsaturated species such as oleic acid and squalene reduced the observed rates significantly.

  3. Polycyclic aromatic hydrocarbons in dust emitted from stoker - fired boilers.

    PubMed

    Kozielska, B; Konieczynski, J

    2007-08-01

    In the present paper, results of investigations of Polycyclic Aromatic Hydrocarbons (PAHs) in granulometric fractions of dust, emitted from 9 hard coal fired mechanic stoker boilers, are presented. Exhaust gases were sampled with a Mark III dust sampler. Extracts derived from the dust fractions were analysed by using Gas Chromatography (GC). The 16 PAHs, total PAHs and equivalent benzo(a)pyrene (B(a)P) were determined. Results of measurements averaged over all examined boilers are presented as concentrations, contents and contributions of investigated hydrocarbons to particular standardised fractions of dust classified according to particle sizes. Distributions of PAHs and their profiles in the dust fractions were determined. The emission factors for B(a)P and Toxic Equivalent B(a)P (TE B(a)P) were determined and proved to be several times higher than for pulverised fuel fired boilers. In the emitted dust, 73% of the total PAHs most hazardous to human health are comprised in PM1.

  4. Assessment of honey contamination with polycyclic aromatic hydrocarbons.

    PubMed

    Ciemniak, Artur; Witczak, Agata; Mocek, Kamila

    2013-01-01

    The aim of this study was to assess honey contamination by polycyclic aromatic hydrocarbons. Six species of honey were examined, as well as rape blossom and soil from villages Pęczerzyno and Przybysław in West Pomerania, Poland. The instrumental analysis was performed using a HP 6890 gas chromatograph coupled to a HP 5973 mass spectrometer with selected ion monitoring (SIM). Quantification was done by gas chromatography-mass spectrometry (GC-MS) using perdeuterated internal standards. Both soil samples showed high levels of all 23 PAHs, whereas honey contained mostly non-carcinogenic PAHs of low molecular weight. The most contaminated honey from Pęczerzyno contained 0.24 μg kg-1 benzo[a]pyrene. Moreover, despite low contamination of honey, a positive correlation was found between PAH content in honey, blossom and soil.

  5. Polycyclic Aromatic Hydrocarbons in Mussels from a South American Estuary.

    PubMed

    Oliva, Ana L; Arias, Andrés H; Quintas, Pamela Y; Buzzi, Natalia S; Marcovecchio, Jorge E

    2017-03-18

    Bivalves, especially mussels, have been pointed as putative species to monitor polycyclic aromatic hydrocarbons (PAHs) in marine environment. After several environmental PAHs baseline reports, the present study was conducted to assess for the first time the levels of PAHs in native mussels (Brachidontes rodriguezii) collected from a critical industrialized estuary of Argentina. Under this objective, after an 18-month sampling period, 34 pools of mussels were assessed for 17 PAHs, including the 16 compounds prioritized by United States Environmental Protection Agency. By means of gas chromatography-mass spectrometry analysis, results showed total PAHs concentrations in mussel's tissue ranged from under laboratory detection limits to 482.4 ng/g dry weight. Mussel body burdens were dominated by lower molecular weight PAHs, such as phenanthrene, naphthalene, and pyrene, whereas the overall PAHs profile suggested the predominance of petrogenic sources. Finally, the potential ecotoxicological impact was evaluated by applying Environmental Assessment Criteria and benzo[a]pyrene toxic equivalent factors.

  6. Extraction of polycyclic aromatic hydrocarbons from spiked soil

    SciTech Connect

    Coover, M.P.; Sims, R.C.; Doucette, W.

    1987-11-01

    A homogenization method was evaluated for extracting polycyclic aromatic hydrocarbons (PAHs) from soils. Fifteen PAHs were spiked and recovered from 2 soils at concentrations ranging from 1 to 1000 micrograms/g, using the homogenization method and a Soxhlet extraction method. Each extraction method performed well in removing the 15 PAHs from both soils over a broad range of concentrations. In general, Soxhlet extraction yielded slightly but significantly (P less than 0.05) higher recoveries than did the homogenization method. The homogenization method, however, was easy to use, and the extraction step turnaround time was less than 15 min/sample. The method should be suitable for other applications requiring the extraction of hydrophobic organic compounds from soils.

  7. NMR shifts for polycyclic aromatic hydrocarbons from first-principles

    SciTech Connect

    Thonhauser, Timo; Ceresoli, Davide; Marzari, Nicola N.

    2009-09-03

    We present first-principles, density-functional theory calculations of the NMR chemical shifts for polycyclic aromatic hydrocarbons, starting with benzene and increasing sizes up to the one- and two-dimensional infinite limits of graphene ribbons and sheets. Our calculations are performed using a combination of the recently developed theory of orbital magnetization in solids, and a novel approach to NMR calculations where chemical shifts are obtained from the derivative of the orbital magnetization with respect to a microscopic, localized magnetic dipole. Using these methods we study on equal footing the 1H and 13C shifts in benzene, pyrene, coronene, in naphthalene, anthracene, naphthacene, and pentacene, and finally in graphene, graphite, and an infinite graphene ribbon. Our results show very good agreement with experiments and allow us to characterize the trends for the chemical shifts as a function of system size.

  8. Polycyclic Aromatic Hydrocarbons and Infrared Astrophysics with Spitzer

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

    Over the past fifteen years, thanks to significant, parallel advancements in observational, experimental, and theoretical techniques, tremendous strides have been made in our understanding of the role that carbon-rich plays in the interstellar medium (ISM). Twenty years ago, the possible existence of an abundant population of large, carbon-rich molecules in the ISM was unthinkable. Today, the unmistakable spectroscopic signatures of polycyclic aromatic hydrocarbons (PAHs) - shockingly large molecules by the standards of traditional interstellar chemistry -are recognized throughout the Universe. In this presentation, we will examine the current state of the interstellar PAH model and explore how this data, in conjunction with the unparalleled observational data provided by the Spitzer Space Telescope, can be used to draw ever-deeper insights into the physical and chemical natures of a wide range of astrophysical environments.

  9. In situ groundwater aeration of polycyclic aromatic hydrocarbons

    SciTech Connect

    Symons, B.D.; Linkenheil, R.; Pritchard, D.; Shanke, C.A.; Seep, D.

    1995-12-31

    At a former wood treating site in Minnesota, the feasibility of in situ groundwater aeration was investigated in a laboratory treatability setting, to evaluate biodegradability and optimal operation conditions of the site aquifer. After concluding that an aeration system would increase the dissolved oxygen concentrations in the groundwater enough to sustain microbial life, a field demonstration system was designed and installed. The system was operated for 1 year, during which groundwater quality at upgradient and downgradient wells was monitored to evaluate the system`s effectiveness. The groundwater aeration system successfully reduced groundwater polycyclic aromatic hydrocarbon (PAH) concentrations, especially naphthalene. Naphthalene concentrations were reduced from 1,319 {micro}g/L to below the laboratory detection limit of 0.5 {micro}g/L. Cumulative concentrations of other PAH compounds were reduced from 98 {micro}g/L to 23 {micro}g/L during the 1-year test.

  10. Polycyclic aromatic hydrocarbons in fuel-oil contaminated soils, Antarctica.

    PubMed

    Aislabie, J; Balks, M; Astori, N; Stevenson, G; Symons, R

    1999-12-01

    Where fuel oil spills have occurred on Antarctic soils polycyclic aromatic hydrocarbons (PAH) may accumulate. Surface and subsurface soil samples were collected from fuel spill sites up to 30 years old, and from nearby control sites, and analysed for the 16 PAHs on the USEPA priority pollutants list, as well as for two methyl substituted naphthalenes, 1-methylnaphthalene and 2-methylnaphthalene. PAH levels ranged from 41-8105 ng g-1 of dried soil in the samples from contaminated sites and were below detection limits in control site samples. PAH were detected in surface soils and had migrated to lower depths in the contaminated soil. The predominant PAH detected were naphthalene and its methyl derivatives.

  11. Metabolism of polycyclic aromatic hydrocarbons in the aquatic environment

    SciTech Connect

    Varanasi, U.

    1989-01-01

    During the past decade, knowledge of polycyclic aromatic hydrocarbons (PAH) in the aquatic environment has advanced substantially to encompass studies of bioavailability, metabolism, subsequent toxic effects, and their ecological consequences. In this book, recent advances in the areas of PAH biogeochemistry and bioaccumulation, microbial degradation, enzymes of activation and detoxication, metabolism of PAH, and laboratory and field studies on carcinogenic/toxic effects, are presented. Additionally, important similarities and differences in metabolism of PAH by aquatic and terrestrial organisms are discussed. These chapters also illustrate that although considerable progress has been made in certain areas of PAH metabolism in the aquatic environment, the field is relatively unexplored and many exciting possibilities exist for future investigations. Separate abstracts are included for 9 chapters in this book for inclusion in the appropriate data bases.

  12. Polycyclic Aromatic Hydrocarbons and Infrared Astrophysics with Spitzer

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

    Over the past fifteen years, thanks to significant, parallel advancements in observational, experimental, and theoretical techniques, tremendous strides have been made in our understanding of the role that carbon-rich plays in the interstellar medium (ISM). Twenty years ago, the possible existence of an abundant population of large, carbon-rich molecules in the ISM was unthinkable. Today, the unmistakable spectroscopic signatures of polycyclic aromatic hydrocarbons (PAHs) - shockingly large molecules by the standards of traditional interstellar chemistry -are recognized throughout the Universe. In this presentation, we will examine the current state of the interstellar PAH model and explore how this data, in conjunction with the unparalleled observational data provided by the Spitzer Space Telescope, can be used to draw ever-deeper insights into the physical and chemical natures of a wide range of astrophysical environments.

  13. Polycyclic Aromatic Aerosol Components: Chemical Analysis and Reactivity

    NASA Astrophysics Data System (ADS)

    Schauer, C.; Niessner, R.; Pöschl, U.

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants in the atmosphere and originate primarily from incomplete combustion of organic matter and fossil fuels. Their main sources are anthropogenic (e.g. vehicle emissions, domes- tic heating or tobacco smoke), and PAHs consisting of more than four fused aromatic rings reside mostly on combustion aerosol particles, where they can react with atmo- spheric trace gases like O3, NOx or OH radicals leading to a wide variety of partially oxidized and nitrated derivatives. Such chemical transformations can strongly affect the activity of the aerosol particles as condensation nuclei, their atmospheric residence times, and consequently their direct and indirect climatic effects. Moreover some poly- cyclic aromatic compounds (PACs = PAHs + derivatives) are known to have a high carcinogenic, mutagenic and allergenic potential, and are thus of major importance in air pollution control. Furthermore PACs can be used as well defined soot model sub- stances, since the basic structure of soot can be regarded as an agglomerate of highly polymerized PAC-layers. For the chemical analysis of polycyclic aromatic aerosol components a new analyti- cal method based on LC-APCI-MS has been developed, and a data base comprising PAHs, Oxy-PAHs and Nitro-PAHs has been established. Together with a GC-HRMS method it will be applied to identify and quantify PAHs and Nitro-PAHs in atmo- spheric aerosol samples, diesel exhaust particle samples and model soot samples from laboratory reaction kinetics and product studies. As reported before, the adsorption and surface reaction rate of ozone on soot and PAH-like particle surfaces is reduced by competitive adsorption of water vapor at low relative humidity (< 25 %). Recent results at higher relative humidities (ca. 50 %), however, indicate re-enhanced gas phase ozone loss, which may be due to absorbtion of ozone into an aqueous surface layer. The interaction of ozone and nitrogen

  14. CHEMISTRY OF OXIDATION OF POLYCYCLIC AROMATIC HYDROCARBONS BY SOIL PSEUDOMONADS

    PubMed Central

    Rogoff, Martin H.

    1962-01-01

    Rogoff, Martin H. (U.S. Bureau of Mines, Pittsburgh, Pa.). Oxidation of polycyclic aromatic hydrocarbons by soil pseudomonads. J. Bacteriol. 83:998–1004. 1962.—Substitution of phenanthrene by a methyl group at the 9-carbon blocks oxidation of the compound by a resting-cell suspension of a phenanthrene-grown soil pseudomonad. When 2-methylphenanthrene is provided, the oxidation rate is considerably higher; 3-methylphenanthrene is oxidized at a rate intermediate between the other two, even though the methyl group is attached to a carbon directly involved in ring splitting. Cells grown on naphthalene or anthracene oxidize phenanthrene at a much lower rate than cells grown with phenanthrene or 2-methylnaphthalene as the source of carbon. Naphthalene-grown cells also absorb less phenanthrene from aqueous solution than do their phenanthrene-grown counterparts. The data are in keeping with the hypothesis that polynuclear aromatic hydrocarbons attach to the relevant bacterial enzymes at carbon-carbon bonds of high electron density (K regions; localized double bonds), and that the ring-splitting reactions then occur at other bonds on the substrate molecule. The actual bond that undergoes fission is determined by the electronic and steric configurations of the enzyme-substrate complex. When linearly arranged aromatic compounds such as naphthalene or anthracene are attacked, attachment to an enzyme and ring splitting may take place on the same ring; angular aromatic compounds such as phenanthrene afford attachment to an enzyme at a bond in a ring other than the one containing the ring-splitting site. PMID:14493381

  15. A review of polycyclic aromatic hydrocarbons (PAHs) research progress in China based on CNKI database

    NASA Astrophysics Data System (ADS)

    Zhang, Zhao

    2017-03-01

    This article using the retroactive content analysis method summarizes the research progress of air polycyclic aromatic hydrocarbons during 1983 to 2016, and is based on the 72 search results about "Air Polycyclic Aromatic Hydrocarbons" in CNKI database. This article directly points out the study achievements and improvements about air polycyclic aromatic hydrocarbons from 4 aspects, the reviews of the studies of PAHs in a special stage, the studies on PAHs determination and analysis method, the studies on PAHs concentration in different places and the studies on the relationship between PAHs concentration in air and human health, respectively.

  16. Prenatal Exposure to Polycyclic Aromatic Hydrocarbons /Aromatics, BDNF and Child Development

    PubMed Central

    Perera, Frederica; Phillips, David H.; Wang, Ya; Roen, Emily; Herbstman, Julie; Rauh, Virginia; Wang, Shuang; Tang, Deliang

    2015-01-01

    Objectives Within a New York City (NYC) birth cohort, we assessed the associations between polycyclic aromatic hydrocarbon (PAH) and other aromatic DNA adducts and brain derived neurotrophic factor (BDNF) concentrations in umbilical cord blood, and neurodevelopment at age 2 years and whether BDNF is a mediator of the associations between PAH/aromatic-DNA adducts and neurodevelopment. Methods PAH/aromatic-DNA adduct concentrations in cord blood were measured in 505 children born to nonsmoking African-American and Dominican women residing in NYC, and a subset was assessed for neurodevelopment at 2 years using the Bayley Scales of Infant Development Mental Development Index (MDI). A spectrum of PAH/aromatic-DNA adducts was measured using the 32P-postlabeling assay; DNA adducts formed by benzo[a]pyrene (B[a]P), a representative PAH, were measured by High Performance Liquid Chromatography (HPLC)/fluorescence. BDNF mature protein in cord blood plasma was quantified by an ELISA. Multivariate regression analysis, adjusting for potential confounders, was conducted. Results PAH/aromatic-DNA adduct concentration measured by postlabeling was inversely associated with BDNF concentration (p=0.02) and with MDI scores at 2 years (p=0.04). BDNF level was positively associated with MDI scores (p=0.003). Restricting to subjects having all three measures (PAH/aromatic-DNA adducts by postlabeling, MDI, and BDNF), results were similar but attenuated (p=0.13, p=0.05, p=0.01, respectively). Associations between B[a]P-DNA adducts and BDNF and B[a]P-DNA adducts and MDI at age 2 years were not significant. At age 3 years, the positive association of BDNF with MDI was not observed. Conclusions The results at age 2 suggest that prenatal exposure to a spectrum of PAH/aromatic pollutants may adversely affect early neurodevelopment, in part by reducing BDNF levels during the fetal period. However, the same relationship was not seen at age 3. PMID:26301740

  17. Scavenging ratios of polycyclic aromatic compounds in rain and snow in the Athabasca oil sands region

    NASA Astrophysics Data System (ADS)

    Zhang, L.; Cheng, I.; Muir, D.; Charland, J.-P.

    2015-02-01

    The Athabasca oil sands industry in northern Alberta, Canada, is a possible source of polycyclic aromatic compounds (PACs). Monitored PACs, including polycyclic aromatic hydrocarbons (PAHs), alkylated PAHs, and dibenzothiophenes (DBTs), in precipitation and in air at three near-source sites in the Fort MacKay and Fort McMurray area during January 2011 to May 2012, were used to generate a database of scavenging ratios (Wt) for PACs scavenged by both snow and rain. Higher concentrations in precipitation and air were observed for alkylated PAHs and DBTs compared to the other PACs. The sums of the median precipitation concentrations over the period of data analyzed were 0.48 μ g L-1 for the 18 PAHs, 3.38 μ g L-1 for the 20 alkylated PAHs, and 0.94 μ g L-1 for the 5 DBTs. The sums of the median air concentrations for parent PAHs, alkylated PAHs, and DBTs were 8.37, 67.26, and 11.83 ng m-3, respectively. Median Wt over the measurement period were 6100 - 1.1 × 106 from snow scavenging and 350 - 2.3 × 105 from rain scavenging depending on the PAC species. Median Wt for parent PAHs were within the range of those observed at other urban and suburban locations, but Wt for acenaphthylene in snow samples were 2-7 times higher compared to other urban and suburban locations. Wt for some individual snow and rain samples exceeded literature values by a factor of 10. Wt for benzo(a)pyrene, dibenz(a,h)anthracene, and benzo(g,h,i)perylene in snow samples had reached 107, which is the maximum for PAH snow scavenging ratios reported in the literature. From the analysis of data subsets, Wt for particulate-phase dominant PACs were 14-20 times greater than gas-phase dominant PACs in snow samples and 7-20 times greater than gas-phase dominant PACs in rain samples. Wt from snow scavenging were ~ 9 times greater than from rain scavenging for particulate-phase dominant PACs and 4-9.6 times greater than from rain scavenging for gas-phase dominant PACs. Gas-particle fractions of each PAC

  18. The unique aromatic catabolic genes in sphingomonads degrading polycyclic aromatic hydrocarbons (PAHs).

    PubMed

    Pinyakong, Onruthai; Habe, Hiroshi; Omori, Toshio

    2003-02-01

    Many members of the sphingomonad genus isolated from different geological areas can degrade a wide variety of polycyclic aromatic hydrocarbons (PAHs) and related compounds. These sphingomonads such as Sphingobium yanoikuyae strain B1, Novosphingobium aromaticivorans strain F199, and Sphingobium sp. strain P2 have been found to possess a unique group of genes for aromatic degradation, which are distantly related with those in pseudomonads and other genera reported so far both in sequence homology and gene organization. Genes for aromatics degradation in these sphingomonads are complexly arranged; the genes necessary for one degradation pathway are scattered through several clusters. These aromatic catabolic gene clusters seem to be conserved among many other sphingomonads such as Sphingobium yanoikuyae strain Q1, Sphingomonas paucimobilis strain TNE12, S. paucimobilis strain EPA505, Sphingobium agrestis strain HV3, and Sphingomonas chungbukensis strain DJ77. Furthermore, some genes for naphthalenesulfonate degradation found in Sphingomonas xenophaga strain BN6 also share a high sequence homology with their homologues found in these sphingomonads. On the other hand, protocatechuic catabolic gene clusters found in fluorene-degrading Sphingomonas sp. strain LB126 appear to be more closely related with those previously found in lignin-degrading S. paucimobilis SYK-6 than the genes in this group of sphingomonads. This review summarizes the information on the distribution of these strains and relationships among their aromatic catabolic genes.

  19. Infrared Spectroscopy of Matrix-Isolated Polycyclic Aromatic Compounds and their Ions. 6; Polycyclic Aromatic Nitrogen Heterocycles

    NASA Technical Reports Server (NTRS)

    Mattioda, A. L.; Hudgins, Douglas M.; Bauschlicher, C. W., Jr.; Rosi, M.; Allamandola, L. J.; DeVincenzi, D. (Technical Monitor)

    2002-01-01

    The matrix-isolation technique has been employed to measure the mid-infrared spectra of several polycyclic aromatic nitrogen heterocycles in both neutral and cationic forms. The species studied include: 7,8 benzoquinoline (C13H9N); 2-azapyrene (C15H9N); 1- and 2-azabenz(a)anthracene (C17H11N); and 1-, 2-, and 4-azachrysene (also C17H11N). The experimentally measured band frequencies and intensities for each molecule are tabulated and compared with their theoretically calculated values computed using density functional theory at the B3LYP/4-31G level. The overall agreement between experiment and theory is quite good, in keeping with previous investigations involving the parent aromatic hydrocarbons. Several interesting spectroscopic trends are found to accompany nitrogen substitution into the aromatic framework of these compounds. First, for the neutral species, the nitrogen atom produces a significant increase in the total integrated infrared intensity across the 1600 - 1100/cm region and plays an essential role in the molecular vibration that underlies an uncharacteristically intense, discrete feature that is observed near 1400/cm in the spectra of 7,8 benzoquinoline, 1-azabenz(a)anthracene, and 4-azachrysene. The origin of this enhanced infrared activity and the nature of the new 1400/cm vibrational mode are explored. Finally, in contrast to the parent hydrocarbon species, these aromatic nitrogen heterocycles possess a significant permanent dipole moment. Consequently, these dipole moments and the rotational constants are reported for these species in their neutral and ionized forms.

  20. Large Abundances of Polycyclic Aromatic Hydrocarbons in Titan's Upper Atmosphere

    NASA Technical Reports Server (NTRS)

    Lopez-Puertas, M.; Dinelli, B. M.; Adriani, A.; Funke, B.; Garcia-Comas, M.; Moriconi, M. L.; D'Aversa, E.; Boersma, C.; Allamandola, L. J.

    2013-01-01

    In this paper, we analyze the strong unidentified emission near 3.28 micron in Titan's upper daytime atmosphere recently discovered by Dinelli et al.We have studied it by using the NASA Ames PAH IR Spectroscopic Database. The polycyclic aromatic hydrocarbons (PAHs), after absorbing UV solar radiation, are able to emit strongly near 3.3 micron. By using current models for the redistribution of the absorbed UV energy, we have explained the observed spectral feature and have derived the vertical distribution of PAH abundances in Titan's upper atmosphere. PAHs have been found to be present in large concentrations, about (2-3) × 10(exp 4) particles / cubic cm. The identified PAHs have 9-96 carbons, with a concentration-weighted average of 34 carbons. The mean mass is approx 430 u; the mean area is about 0.53 sq. nm; they are formed by 10-11 rings on average, and about one-third of them contain nitrogen atoms. Recently, benzene together with light aromatic species as well as small concentrations of heavy positive and negative ions have been detected in Titan's upper atmosphere. We suggest that the large concentrations of PAHs found here are the neutral counterpart of those positive and negative ions, which hence supports the theory that the origin of Titan main haze layer is located in the upper atmosphere.

  1. Nucleobases in Space: Laboratory Studies of Polycyclic Aromatic Nitrogen Heterocycles

    NASA Technical Reports Server (NTRS)

    Elsila, Jamie; Mattioda, Andy; Bernstein, Max; Sandford, Scott; Hudgins, Doug

    2005-01-01

    Polycyclic Aromatic Nitrogen Heterocycles (PANHs) are heterocyclic aromatics Le., PAHs with carbon atoms replaced by a nitrogen atom. These molecules have been detected in meteorite extracts, and in general these nitrogen heterocycles are of astrobiological interest since this class of molecules include nucleobases, basic components of our nucleic acids. These compounds are predicted to be present in the interstellar medium and in Titan tholin, but have received relatively little attention. We will present spectra and reactions of PANHs, frozen in solid H2O at 12 K, conditions germane to astronomical observations. In contrast to simple PAHs, that do not interact strongly with solid H2O, the nitrogen atoms in PANHs are potentially capable of hydrogen bonding with H20 changing their spectra, complicating their remote detection on the surfaces of icy bodies. Moreover, we have studied the photo-chemistry of these interesting compounds under astrophysical conditions and will use our lab studies to assess a potential interstellar heritage of these compounds in carbonaceous chondrites.

  2. Sorption of polycyclic aromatic hydrocarbons to polystyrene nanoplastic.

    PubMed

    Liu, Lijing; Fokkink, Remco; Koelmans, Albert A

    2016-07-01

    Microplastic has become an emerging contaminant of global concern. Bulk plastic can degrade to form smaller particles down to the nanoscale (<100 nm), which are referred to as nanoplastics. Because of their high surface area, nanoplastic may bind hydrophobic chemicals very effectively, increasing their hazard when such nanoplastics are taken up by biota. The present study reports distribution coefficients for sorption of polycyclic aromatic hydrocarbons (PAHs) to 70 nm polystyrene in freshwater, and PAH adsorption isotherms spanning environmentally realistic aqueous concentrations of 10(-5)  μg/L to 1 μg/L. Nanopolystyrene aggregate state was assessed using dynamic light scattering. The adsorption isotherms were nonlinear, and the distribution coefficients at the lower ends of the isotherms were very high, with values up to 10(9) L/kg. The high and nonlinear sorption was explained from π-π interactions between the planar PAHs and the surface of the aromatic polymer polystyrene and was higher than for micrometer-sized polystyrene. Reduction of nanopolystyrene aggregate sizes had no significant effect on sorption, which suggests that the PAHs could reach the sorption sites on the pristine nanoparticles regardless of the aggregation state. Pre-extraction of the nanopolystyrene with C18 polydimethylsiloxane decreased sorption of PAHs, which could be explained by removal of the most hydrophobic fraction of the nanopolystyrene. Environ Toxicol Chem 2016;35:1650-1655. © 2015 SETAC.

  3. POLYCYCLIC AROMATIC HYDROCARBON CLUSTERS AS SOURCES OF INTERSTELLAR INFRARED EMISSION

    SciTech Connect

    Roser, J. E.; Ricca, A.

    2015-03-10

    Polycyclic aromatic hydrocarbons (or PAHs) have been the subject of astrochemical research for several decades as principal sources of the interstellar aromatic infrared emission bands. PAH clusters could possibly contribute to these emission bands, but a lack of data on their infrared properties has made this hypothesis difficult to evaluate. Here we investigate homogeneous neutral PAH clusters by measuring the mid-infrared absorption spectra of the five nonlinear PAH molecules phenanthrene, chrysene, pyrene, perylene, and benzo[ghi]perylene within solid argon ice at a fixed temperature of 5 K. We attribute observed spectral shifts in their principal absorption bands as a function of argon/PAH ratio to clustering of the PAH molecules within the argon matrix. These shifts are related to the cluster structures forming in the matrix and the topology of the monomer PAH molecule. We predict that interstellar PAH molecules that are relatively large (no fewer than 50 carbon atoms per molecule) and compact will have clusters that contribute to the asymmetrically red-shaded profile of the interstellar 11.2 μm emission band.

  4. Polycyclic aromatic hydrocarbons (PAHs) in livers of California sea otters.

    PubMed

    Kannan, Kurunthachalam; Perrotta, Emily

    2008-03-01

    Concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) were measured in livers of 81 adult female sea otters collected along the California coast in 1992-2002. Concentrations of summation operatorPAHs in livers of sea otters were in the range of 588-17400ng/g lipid wt (mean: 3880ng/g, lipid wt). On a wet weight basis, the concentrations ranged from 17 to 1430ng/g (mean: 146ng/g). Overall, di- and tri-cyclic aromatic hydrocarbons, namely, naphthalene, fluorene, phenanthrene/anthracene, and acenaphthylene, were the predominant compounds found in the livers. Although petroleum-related sources appear to be the major contributors to PAH exposure in sea otters, exposure sources varied by geographical sub-regions. Dibenz[a,h]anthracene was found to comprise a significant proportion of the summation operatorPAH concentrations in sea otters from the northern sub-region of the study area. No significant difference existed in the concentrations of summation operatorPAHs among sea otters that died from infectious diseases, emaciation, and noninfectious causes. Concentrations of summation operatorPAHs in livers of sea otters decreased significantly from 1992 to 2002. Because of the rapid metabolism of PAHs in marine mammals such as sea otters, further studies examining the association of PAHs with health effects should determine hydroxylated metabolites in livers.

  5. Nucleobases in Space: Laboratory Studies of Polycyclic Aromatic Nitrogen Heterocycles

    NASA Technical Reports Server (NTRS)

    Elsila, Jamie; Mattioda, Andy; Bernstein, Max; Sandford, Scott; Hudgins, Doug

    2005-01-01

    Polycyclic Aromatic Nitrogen Heterocycles (PANHs) are heterocyclic aromatics Le., PAHs with carbon atoms replaced by a nitrogen atom. These molecules have been detected in meteorite extracts, and in general these nitrogen heterocycles are of astrobiological interest since this class of molecules include nucleobases, basic components of our nucleic acids. These compounds are predicted to be present in the interstellar medium and in Titan tholin, but have received relatively little attention. We will present spectra and reactions of PANHs, frozen in solid H2O at 12 K, conditions germane to astronomical observations. In contrast to simple PAHs, that do not interact strongly with solid H2O, the nitrogen atoms in PANHs are potentially capable of hydrogen bonding with H20 changing their spectra, complicating their remote detection on the surfaces of icy bodies. Moreover, we have studied the photo-chemistry of these interesting compounds under astrophysical conditions and will use our lab studies to assess a potential interstellar heritage of these compounds in carbonaceous chondrites.

  6. LARGE ABUNDANCES OF POLYCYCLIC AROMATIC HYDROCARBONS IN TITAN'S UPPER ATMOSPHERE

    SciTech Connect

    Lopez-Puertas, M.; Funke, B.; Garcia-Comas, M.; Dinelli, B. M.; Adriani, A.; D'Aversa, E.; Moriconi, M. L.; Boersma, C.; Allamandola, L. J.

    2013-06-20

    In this paper, we analyze the strong unidentified emission near 3.28 {mu}m in Titan's upper daytime atmosphere recently discovered by Dinelli et al. We have studied it by using the NASA Ames PAH IR Spectroscopic Database. The polycyclic aromatic hydrocarbons (PAHs), after absorbing UV solar radiation, are able to emit strongly near 3.3 {mu}m. By using current models for the redistribution of the absorbed UV energy, we have explained the observed spectral feature and have derived the vertical distribution of PAH abundances in Titan's upper atmosphere. PAHs have been found to be present in large concentrations, about (2-3) Multiplication-Sign 10{sup 4} particles cm{sup -3}. The identified PAHs have 9-96 carbons, with a concentration-weighted average of 34 carbons. The mean mass is {approx}430 u; the mean area is about 0.53 nm{sup 2}; they are formed by 10-11 rings on average, and about one-third of them contain nitrogen atoms. Recently, benzene together with light aromatic species as well as small concentrations of heavy positive and negative ions have been detected in Titan's upper atmosphere. We suggest that the large concentrations of PAHs found here are the neutral counterpart of those positive and negative ions, which hence supports the theory that the origin of Titan main haze layer is located in the upper atmosphere.

  7. Partition characteristics of polycyclic aromatic hydrocarbons on soils and sediments

    USGS Publications Warehouse

    Chiou, C.T.; Mcgroddy, S.E.; Kile, D.E.

    1998-01-01

    The partition behavior was determined for three polycyclic aromatic hydrocarbons (PAHs), i.e., naphthalene, phenanthrene, and pyrene, from water to a range of soil and sediment samples. The measured partition coefficients of the individual PAHs between soil/sediment organic matter (SOM) and water (i.e., K(oc) values) are relatively invariant either for the 'clean' (uncontaminated) soils or for the clean sediments; however, the mean K(oc) values on the sediments are about twice the values on the soils. This disparity is similar to the earlier observation for other nonpolar solutes and reflects the compositional differences between soil and sediment organic matters. No significant differences in K(oc) are observed between a clean coastal marine sediment and freshwater sediments. The coastal sediments that are significantly impacted by organic contaminants exhibit higher K(oc) values. At given K(ow) values (octanol-water), the PAHs exhibit much higher K(oc) values than other relatively nonpolar solutes (e.g., chlorinated hydrocarbons). This effect is shown to result from the enhanced partition of PAHs to SOM rather than from lower K(ow) values of PAHs at given supercooled liquid solute solubilities in water. The enhanced partition of PAHs over other nonpolar solutes in SOM provides an account of the markedly different correlations between log K(oc) and log K(ow) for PAHs and for other nonpolar solutes. The improved partition of PAHs in SOM stems apparently from the enhanced compatibility of their cohesive energy densities with those of the aromatic components in SOM. The approximate aromatic fraction in soil/sediment organic matter has been assessed by solid-state 13C-NMR spectroscopy.The partition behavior was determined for three polycyclic aromatic hydrocarbons (PAHs), i.e., naphthalene, phenanthrene, and pyrene, from water to a range of soil and sediment samples. The measured partition coefficients of the individual PAHs between soil/sediment organic matter (SOM

  8. Chemical Kinetics of Polycyclic Aromatic Hydrocarbons in Comet Impacts

    NASA Astrophysics Data System (ADS)

    Kress, M. E.; McKay, C.; Tielens, A. G.; Frenklach, M.

    2004-12-01

    Polycyclic aromatic hydrocarbons (PAHs) are stable, robust organic compounds that would have been an important constituent of the early atmospheres of terrestrial planets. These strongly-bound molecules readily absorb ultraviolet light and may play a role in aerosol formation. PAHs are one of the predominant carriers of carbon in interstellar space, after CO. They are common in carbonaceous chondrites, and quite likely in comets as well. Impacts of volatile-rich planetesimals such as carbonaceous chondrites and comets would have been common during the late stages of planet formation. Theoretical studies of impact chemistry typically assume that the chemical composition of the post-impact material is given by thermodynamic equilibrium at 2000 K. These calculations also typically ignore the formation of aromatic compounds because the closure of the first aromatic ring is kinetically inhibited, although thermodynamically favorable at the temperatures and pressures of an impact fireball. Do the PAHs present in a comet or asteroid survive impact? If so, how are these PAHs modified during impact? To address these questions, we model the chemical kinetics of PAH survival, formation, growth and destruction within a parameter space consisting of impact fireball cooling timescales, pressures, temperatures, C/O ratios and other factors. The chemistry of PAHs has been well studied under conditions present in plug flow reactors and sooting flames (P ≈ 1atm, T≥ 1000 K). We hope that our results will motivate more experimental investigation of reaction mechanisms and rate coefficients for a broader range of temperatures and pressures than those heretofore studied for industrial applications. This work has been supported by the NASA Astrobiology Institute's Virtual Planetary Laboratory and the Institute for Geophysics and Planetary Physics at Lawrence Livermore National Laboratory.

  9. Food heating and the formation of heterocyclic aromatic amine and polycyclic aromatic hydrocarbon mutagens/carcinogens.

    PubMed

    Knize, M G; Salmon, C P; Pais, P; Felton, J S

    1999-01-01

    Heterocyclic aromatic amines (HAA) and polycyclic aromatic hydrocarbons (PAH) are mutagens and animal carcinogens sometimes formed when foods are heated or processed. Determining their role in cancer etiology depends on comparing human exposures and determining any significant dose-related effects. Chemical analysis of foods shows that flame-grilling can form both PAH and HAA, and that frying forms predominantly HAA. With detection limits of about 0.1 ng/g, amounts found in commercially processed or restaurant foods range from 0.1 to 14 ng/g for HAA, and levels of PAH up to 1 ng/g in a liquid smoke flavoring. Laboratory fried samples have greater amounts of PAH, up to 38 ng/g in hamburgers, and high levels of HAA, over 300 ng/g, are measured in grilled chicken breast. Understanding the processing conditions that form PAH and HAA can lead to methods to greatly reduce their occurrence in processed foods.

  10. Inversion and rotation processes involving non-planar aromatic compounds catalyzed by extended polycyclic aromatic hydrocarbons

    NASA Astrophysics Data System (ADS)

    Karton, Amir

    2014-10-01

    Using accurate quantum chemical calculations, we show that extended planar polycyclic aromatic hydrocarbons (PAHs) can efficiently catalyze a range of chemical processes involving non-planar aromatic systems. These include (i) bowl-to-bowl inversion of curved PAHs (e.g. corannulene and sumanene), (ii) 'flip-flop' inversion of helicenes (e.g. benzo[c]phenanthrene), and (iii) rotation about the Phsbnd Ph bond in biphenyls. Non-covalent π-π interactions between the planar catalyst and the substrate stabilize the planar transition structures to a greater extent than they stabilize the non-planar reactants. These result in surprisingly large catalytic enhancements (namely, the reaction barrier heights are reduced by 21-63% of the uncatalyzed reaction barriers).

  11. Webinar Presentation: Prenatal Exposures to Polycyclic Aromatic Hydrocarbons (PAH) and Childhood Body Mass Index Trajectories

    EPA Pesticide Factsheets

    This presentation, Prenatal Exposures to Polycyclic Aromatic Hydrocarbons (PAH) and Childhood Body Mass Index Trajectories, was given at the NIEHS/EPA Children's Centers 2015 Webinar Series held on Feb. 11, 2015.

  12. Modeling the Role of Alkanes, Polycyclic Aromatic Hydrocarbons, and Their Oligomers in Secondary Organic Aerosol Formation

    EPA Science Inventory

    A computationally efficient method to treat secondary organic aerosol (SOA) from various length and structure alkanes as well as SOA from polycyclic aromatic hydrocarbons (PAHs) is implemented in the Community Multiscale Air Quality (CMAQ) model to predict aerosol concentrations ...

  13. ASSAYING PARTICLE-BOUND POLYCYCLIC AROMATIC HYDROCARBONS (PAH) FROM ARCHIVED PM2.5 FILTERS

    EPA Science Inventory

    Airborne particulate matter contains numerous organic species, including several polycyclic aromatic hydrocarbons (PAHs) that are known or suspected carcinogens. Existing methods for measuring airborne PAHs are complex and costly, primarily because they are designed to collect...

  14. MUTAGENICITY IN SALMONELLA OF SULFUR-CONTAINING POLYCYCLIC AROMATIC HETEROCYCLES AND THEIR DIHYDRODIOL DERIVATIVES

    EPA Science Inventory

    Polycyclic aromatic sulfur heterocycles (PASH) are common constituents of cigarette smoke, fossil fuel-derived materials, and their combustion byproducts. Many PASH are known mutagens and carcinogens. However, unlike their nonsulfur-containing counterparts, relatively little is k...

  15. Do lagoon area sediments act as traps for polycyclic aromatic hydrocarbons?

    PubMed

    Marini, Mauro; Frapiccini, Emanuela

    2014-09-01

    The coastal lagoons are vulnerable systems, located between the land and the sea, enriched by both marine and continental inputs and are among the most productive aquatic ecosystems. The purpose of this work is to understand the influence of the lagoon area sediments on the behaviour of polycyclic aromatic hydrocarbons, through the adsorption coefficient determination. In fact, the sorption of polycyclic aromatic hydrocarbons is an important process because it governs the fate, transport, bioavailability and toxicity of these compounds in sediments. It has been observed that the adsorption of polycyclic aromatic hydrocarbons in a transitional system is the outcome of different factors, such as their sources and physicochemical properties, salinity and sediment composition, hydrology and environmental conditions. The results showed that transitional areas contribute to the polycyclic aromatic hydrocarbon accumulation in the sediment turning it into a trap.

  16. Modeling the Role of Alkanes, Polycyclic Aromatic Hydrocarbons, and Their Oligomers in Secondary Organic Aerosol Formation

    EPA Science Inventory

    A computationally efficient method to treat secondary organic aerosol (SOA) from various length and structure alkanes as well as SOA from polycyclic aromatic hydrocarbons (PAHs) is implemented in the Community Multiscale Air Quality (CMAQ) model to predict aerosol concentrations ...

  17. Identification of persulfate oxidation products of polycyclic aromatic hydrocarbon during remediation of contaminated soil

    EPA Science Inventory

    The extent of PAH transformation, the formation and transformation of reaction byproducts during persulfate oxidation of polycyclic aromatic hydrocarbons (PAHs) in coking plant soil was investigated. Pre-oxidation analyses indicated that oxygen-containing PAHs (oxy-PAHs) existed ...

  18. Identification of persulfate oxidation products of polycyclic aromatic hydrocarbon during remediation of contaminated soil

    EPA Science Inventory

    The extent of PAH transformation, the formation and transformation of reaction byproducts during persulfate oxidation of polycyclic aromatic hydrocarbons (PAHs) in coking plant soil was investigated. Pre-oxidation analyses indicated that oxygen-containing PAHs (oxy-PAHs) existed ...

  19. PHOTOACTIVATION AND TOXICITY OF MIXTURES OF POLYCYCLIC AROMATIC HYDROCARBON COMPOUNDS IN MARINE SEDIMENT

    EPA Science Inventory

    The direct toxicity and photoinduced toxicity of sediment-associated acenaphthene, phenanthrene, fluoranthene, and pyrene were determined for the marine amphipod Rhepoxynius abronius. The four polycyclic aromatic hydrocarbons (PAHs) were spiked into sediment in a concentration se...

  20. STUDIES ON BIOREMEDIATION OF POLYCYCLIC AROMATIC HYDROCARBON-CONTAMINATED SEDIMENTS: BIOAVAILABILITY, BIODEGRADABILITY, AND TOXICITY ISSUES

    EPA Science Inventory

    The widespread contamination of aquatic sediments by polycyclic aromatic hydrocarbons (PAHs) has created a need for cost-effective bioremediation processes, on which the bioavailability and the toxicity of PAHs often have a significant impact. This research investigated the biode...

  1. MULTISUBSTRATE BIODEGRADATION KINETICS FOR BINARY AND COMPLEX MIXTURES OF POLYCYCLIC AROMATIC HYDROCARBONS

    EPA Science Inventory

    Biodegradation kinetics were studied for binary and complex mixtures of nine polycyclic aromatic hydrocarbons (PAHs): naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, 2-ethylnaphthalene, phenanthrene, anthracene, pyrene, fluorene and fluoranthene. Discrepancies between the ...

  2. MUTAGENICITY IN SALMONELLA OF SULFUR-CONTAINING POLYCYCLIC AROMATIC HETEROCYCLES AND THEIR DIHYDRODIOL DERIVATIVES

    EPA Science Inventory

    Polycyclic aromatic sulfur heterocycles (PASH) are common constituents of cigarette smoke, fossil fuel-derived materials, and their combustion byproducts. Many PASH are known mutagens and carcinogens. However, unlike their nonsulfur-containing counterparts, relatively little is k...

  3. ASSAYING PARTICLE-BOUND POLYCYCLIC AROMATIC HYDROCARBONS (PAH) FROM ARCHIVED PM2.5 FILTERS

    EPA Science Inventory

    Airborne particulate matter contains numerous organic species, including several polycyclic aromatic hydrocarbons (PAHs) that are known or suspected carcinogens. Existing methods for measuring airborne PAHs are complex and costly, primarily because they are designed to collect...

  4. PHOTOACTIVATION AND TOXICITY OF MIXTURES OF POLYCYCLIC AROMATIC HYDROCARBON COMPOUNDS IN MARINE SEDIMENT

    EPA Science Inventory

    The direct toxicity and photoinduced toxicity of sediment-associated acenaphthene, phenanthrene, fluoranthene, and pyrene were determined for the marine amphipod Rhepoxynius abronius. The four polycyclic aromatic hydrocarbons (PAHs) were spiked into sediment in a concentration se...

  5. COMPUTATIONAL METHODS FOR STUDYING THE INTERACTION BETWEEN POLYCYCLIC AROMATIC HYDROCARBONS AND BIOLOGICAL MACROMOLECULES

    EPA Science Inventory

    Computational Methods for Studying the Interaction between Polycyclic Aromatic Hydrocarbons and Biological Macromolecules .

    The mechanisms for the processes that result in significant biological activity of PAHs depend on the interaction of these molecules or their metabol...

  6. STUDIES ON BIOREMEDIATION OF POLYCYCLIC AROMATIC HYDROCARBON-CONTAMINATED SEDIMENTS: BIOAVAILABILITY, BIODEGRADABILITY, AND TOXICITY ISSUES

    EPA Science Inventory

    The widespread contamination of aquatic sediments by polycyclic aromatic hydrocarbons (PAHs) has created a need for cost-effective bioremediation processes, on which the bioavailability and the toxicity of PAHs often have a significant impact. This research investigated the biode...

  7. MULTISUBSTRATE BIODEGRADATION KINETICS FOR BINARY AND COMPLEX MIXTURES OF POLYCYCLIC AROMATIC HYDROCARBONS

    EPA Science Inventory

    Biodegradation kinetics were studied for binary and complex mixtures of nine polycyclic aromatic hydrocarbons (PAHs): naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, 2-ethylnaphthalene, phenanthrene, anthracene, pyrene, fluorene and fluoranthene. Discrepancies between the ...

  8. COMPUTATIONAL METHODS FOR STUDYING THE INTERACTION BETWEEN POLYCYCLIC AROMATIC HYDROCARBONS AND BIOLOGICAL MACROMOLECULES

    EPA Science Inventory

    Computational Methods for Studying the Interaction between Polycyclic Aromatic Hydrocarbons and Biological Macromolecules .

    The mechanisms for the processes that result in significant biological activity of PAHs depend on the interaction of these molecules or their metabol...

  9. DIGESTIVE BIOAVAILABILITY TO A DEPOSIT FEDDER (ARENICOLA MARINA) OF POLYCYCLIC AROMATIC HYDROCARBONS ASSOCIATED WITH ANTHRPOGENIC PARTICLES

    EPA Science Inventory

    Marine sediments around urban areas serve as catch basins for anthropogenic particles containing polycyclic aromatic hydrocarbons (PAHs). Using incubations with gut fluids extracted from a deposit-feeding polychaete (Arenicola marina), we determined the digestive bioavailability ...

  10. Molecular cloning of novel genes for polycyclic aromatic hydrocarbon degradation from Commamonas testosteroni GZ39

    SciTech Connect

    Goyal, A.K.; Zylstra, G.J.

    1996-01-01

    The mechanisms by which bacteria degrade simple polycyclic aromatic compounds have been studied for some time. The genes for the initial steps in the degradation of maphthalene have been cloned from many different Pseudomonas stains. This study was undertaken to investigate the diversity of genes involved in phenanthrene degradation and to identify novel organisms and genes for polycyclic aromatic hydrocarbon degradations. 53 refs., 5 figs., 1 tab.

  11. Alkyl and Aromatic Amines as Digestive Ripening/Size Focusing Agents for Gold Nanoparticles

    PubMed Central

    Sun, Yijun; Jose, Deepa; Sorensen, Christopher; Klabunde, Kenneth J.

    2013-01-01

    Both long chain alkyl thiols and alkyl amines behave as size focusing agents for gold nanoparticles, a process that is under thermodynamic control. However, amines do not oxidize surface gold atoms while thiols do oxidize surface gold to gold(I) with evolution of hydrogen gas. Therefore, alkyl amines participate in digestive ripening by a different mechanism. The efficiency of alkyl amines for this process is described and compared, and ultimate gold particle size differences are discussed. Reported herein is a detailed investigation of alkyl chain lengths for alkyl amines, aromatic amines (aniline), and unusually reactive amines (2-phenylethyl amine). Also, two methods of preparation of the crude gold nanoparticles were employed: gold ion reduction/inverse micelle vs. metal vaporization (Solvated Metal Atom Dispersion—SMAD).

  12. Emission of polycyclic aromatic hydrocarbons from gasohol and ethanol vehicles

    NASA Astrophysics Data System (ADS)

    de Abrantes, Rui; Vicente de Assunção, João; Pesquero, Célia Regina; Bruns, Roy Edward; Nóbrega, Raimundo Paiva

    The exhaust emission of the polycyclic aromatic hydrocarbons (PAHs) considered toxic to human health were investigated on two spark ignition light duty vehicles, one being gasohol (Gasohol, in Brazil, is the generic denomination for mixtures of pure gasoline plus 20-25% of anhydrous ethyl alcohol fuel (AEAF).)-fuelled and the other a flexible-fuel vehicle fuelled with hydrated ethanol. The influence of fuel type and quality, aged lubricant oil type and use of fuel additives on the formation of these compounds was tested using standardized tests identical to US FTP-75 cycle. PAH sampling and chemical analysis followed the basic recommendations of method TO-13 (United States. Environmental Protection Agency, 1999. Compendium Method TO-13A - Determination of polycyclic Aromatic hydrocarbons (PAH) in Ambient Air Using Gas Chromatography/Mass Spectrometry (CG/MS). Center for environmental research information, Cincinnati, p. 78), with the necessary modification for this particular application. Results showed that the total PAH emission factor varied from 41.9 μg km -1 to 612 μg km -1 in the gasohol vehicle, and from 11.7 μg km -1 to 27.4 μg km -1 in the ethanol-fuelled vehicle, a significant difference in favor of the ethanol vehicle. Generally, emission of light molecular weight PAHs was predominant, while high molecular weights PAHs were not detected. In terms of benzo( a)pyrene toxicity equivalence, emission factors varied from 0.00984 μg TEQ km -1 to 4.61 μg TEQ km -1 for the gasohol vehicle and from 0.0117 μg TEQ km -1 to 0.0218 μg TEQ km -1 in the ethanol vehicle. For the gasohol vehicle, results showed that the use of fuel additive causes a significant increase in the emission of naphthalene and phenanthrene at a confidence level of 90% or higher; the use of rubber solvent on gasohol showed a reduction in the emission of naphthalene and phenanthrene at the same confidence level; the use of synthetic oil instead of mineral oil also contributed

  13. The Photochemistry of Polycyclic Aromatic Hydrocarbons (PAHs) in Water Ice

    NASA Astrophysics Data System (ADS)

    Allamandola, L. J.; Bouwman, J.; Cuppen, H.; Gudipati, M. S.; Linnartz, H.

    2009-12-01

    Polycyclic aromatic hydrocarbons (PAHs) and related aromatic materials are present in virtually all phases of the interstellar medium. In dense clouds, they condense out of the gas and become part of the water-rich mixed molecular ices that are a major component of the dust in dense molecular clouds. PAHs are also likely to be frozen on icy Solar System objects. Although the UV radiative processing of simple mixed molecular ices has been studied for nearly 30 years, research into the in-situ photochemistry of PAH containing ices has only recently begun. This paper will review some of that work. The vacuum ultraviolet (VUV) photochemistry of the PAHs naphthalene, pyrene, 4-methylpyrene and quatterylene in water ice at 10 to 30 K will be summarized. In all cases, the neutral parent PAH is readily and efficiently (>70%) converted to the radical cation (PAH+) form upon exposure to VUV radiation. These PAH cations remain trapped and stabilized within the ice to remarkably high temperatures as the ice is warmed to the sublimation point. To understand the chemical processes and kinetics during photolysis we carried out a systematic study on several PAH/H2O ices. A new apparatus was developed which permits tracking the in-situ behavior of the parent PAH and its photoproducts as a function of ice temperature and time with sub-second responsivity. Ice temperature determines the dominant reaction routes while photolysis duration processes the ice. The ability to measure spectra simultaneously with photolysis and with sub-second time resolution permits kinetic studies previously inaccessible and provides new insights into the processes occurring within the ice during photolysis. These studies show that PAHs may well play important but overlooked roles in cosmic ice chemistry and physics, whether they are in the Solar System or near star forming regions in dense clouds.

  14. Polycyclic aromatic hydrocarbons and fatal ischemic heart disease

    SciTech Connect

    Burstyn, I.; Kromhout, H.; Partanen, T.; Svane, O.; Langard, S.; Ahrens, W.; Kauppinen, T.; Stucker, I.; Shaham, J.; Heederik, D.; Ferro, G.; Heikkila, P.; Hooiveld, M.; Johansen, C.; Randem, B.G.; Boffetta, P.

    2005-11-01

    Several toxicologic and epidemiologic studies have produced evidence that occupational exposure to polycyclic aromatic hydrocarbons (PAH) is a risk factor for ischemic heart disease (IHD). However, a clear exposure-response relation has not been demonstrated. We studied a relation between exposure to PAH and mortality from IHD (418 cases) in a cohort of 12,367 male asphalt workers from Denmark, Finland, France, Germany, Israel, The Netherlands and Norway. Exposures to benzo(a)pyrene were assessed quantitatively using measurement-driven exposure models. Exposure to coal tar was assessed in a semiquantitative manner on the basis of information supplied by company representatives. We carried out sensitivity analyses to assess potential confounding by tobacco smoking. Both cumulative and average exposure indices for benzo(a)pyrene were positively associated with mortality from IHD. The highest relative risk for fatal IHD was observed for average benzo(a)pyrene exposures of 273 ng/m{sup 3} or higher, for which the relative risk was 1.64(95% confidence interval = 1.13-2.38). Similar results were obtained for coal tar exposure. Sensitivity analysis indicated that even in a realistic scenario of confounding by smoking, we would observe approximately 20% to 40% excess risk in IHD in the highest PAH-exposure categories. Our results lend support to the hypothesis that occupational PAH exposure causes fatal IHD and demonstrate a consistent exposure-response relation for this association.

  15. Occupational exposure to Polycyclic Aromatic Hydrocarbons in wood dust

    NASA Astrophysics Data System (ADS)

    Huynh, C. K.; Schüpfer, P.; Boiteux, P.

    2009-02-01

    Sino-nasal cancer (SNC) represents approximately 3% of Oto-Rhino-Laryngology (ORL) cancers. Adenocarcinoma SNC is an acknowledged occupational disease affecting certain specialized workers such as joiners and cabinetmakers. The high proportion of woodworkers contracting a SNC, subjected to an estimated risk 50 to 100 times higher than that affecting the general population, has suggested various study paths to possible causes such as tannin in hardwood, formaldehyde in plywood and benzo(a)pyrene produced by wood when overheated by cutting tools. It is acknowledged that tannin does not cause cancer to workers exposed to tea dust. Apart from being an irritant, formaldehyde is also classified as carcinogenic. The path involving carcinogenic Polycyclic Aromatic Hydrocarbons (PAHs) emitted by overheated wood is attractive. In this study, we measured the particle size and PAHs content in dust emitted by the processing of wood in an experimental chamber, and in field situation. Quantification of 16 PAHs is carried out by capillary GC-ion trap Mass Spectrometric analysis (GC-MS). The materials tested are rough fir tree, oak, impregnated polyurethane (PU) oak. The wood dust contains carcinogenic PAHs at the level of μg.g-1 or ppm. During sanding operations, the PU varnish-impregnated wood produces 100 times more PAHs in dust than the unfinished wood.

  16. Polycyclic aromatic hydrocarbon (PAH) ecotoxicology in marine ecosystems.

    PubMed

    Hylland, Ketil

    2006-01-08

    Low levels of oil and hence polycyclic aromatic hydrocarbons (PAHs) are naturally present in the marine environment, although levels have increased significantly following human extraction and use of oil and gas. Other major anthropogenic sources of PAHs include smelters, the use of fossil fuels in general, and various methods of waste disposal, especially incineration. There are two major sources for PAHs to marine ecosystems in Norway: the inshore smelter industry, and offshore oil and gas production activities. A distinction is generally made between petrogenic (oil-derived) and pyrogenic (combustion-derived) PAHs. Although petrogenic PAHs appear to be bioavailable to a large extent, pyrogenic PAHs are often associated with soot particles and less available for uptake into organisms. There is extensive evidence linking sediment-associated PAHs to induction of phase-I enzymes, development of DNA adducts, and eventually neoplastic lesions in fish. Most studies have focused on high-molecular-weight, carcinogenic PAHs such as benzo[a]pyrene. It is less clear how two- and three-ring PAHs affect fish, and there is even experimental evidence to indicate that these chemicals may inhibit some components of the phase I system rather than produce induction. There is a need for increased research efforts to clarify biological effects of two- and three-ring PAHs, PAH mixtures, and adaptation processes in marine ecosystems.

  17. Some carcinogenic polycyclic aromatic hydrocarbons by photoacoustic spectroscopy

    NASA Astrophysics Data System (ADS)

    Garg, R. K.; Kumar, Pardeep; Ram, R. S.; Zaidi, Zahid H.

    1999-12-01

    Polycyclic aromatic hydrocarbons (PAHs) have attracted spectroscopists, astrophysicts and environmentalist because of their importance in our day to day life. It is well known that epoxides are produced during the metabolism of PAHs and have the requisite chemical reactivity to qualify them for the role as an ultimate carcinogenic form of PAHs. Several carcinogenic PAHs such as 3.4-benzopyrene, 1.2,3.4-dibenzopyrene, 3.4,9.10- dibenzopyrene etc. are found to be present in tobacco smoke and among air pollutants. Although PAH molecules are being studied for last several years by using conventional spectroscopy but no systematic attempt has been made to study non-radiative transitions. In our laboratory, we have studied many PAH molecules by a non-destructive technique with unique capability and sensitivity, known as Photoacoustic (PA) spectroscopy. PA spectroscopy is an analytical and research tool to get information about non-radiative transitions and singlet-triplet electronic transitions, where the conventional spectroscopic technique fails. The study of electronic transitions of some carcinogenic molecules are reported using PA and optical absorption spectra in boric acid glass in the region 250 - 400 nm. The electronic transitions of these molecules observed experimentally, have been interpreted using the optimized geometries and CNDO/S-CI method. A good agreement is found between the experimental and calculated results. Assignments of observed electronic transitions are made on the basis of singlet-triplet electronic transitions. Vibrations attached to these electronic transitions are attributed to the ground state vibrational modes.

  18. Superconductivity in an Alkali Doped Polycyclic Aromatic Hydrocarbon, Picene

    NASA Astrophysics Data System (ADS)

    Tokumoto, Madoka; Shimizu, Fumihiko; Hata, Yoshiaki; Sawai, Shinya; Han, Jing; Inoue, Katsuya

    2010-03-01

    The effect of carrier doping into polycyclic aromatic hydrocarbons, including perylene and pentacene, has been extensively studied.[1] As a result of halogen or alkali metal doping, a drastic increase in electrical conductivity was observed. However, superconductivity has not been reported except the one by Sch"on et al.[2] Recently, Kubozono reported that one of them, i.e. picene (C22H14) showed superconductivity at 20 K by doping with potassium.[3] We anticipate that it will lead to surprising findings of hidden organic molecular superconductors. In this presentation, we will report on the characterization of superconducting properties of alkali doped picene. Instead of ordinary vapor phase alkali metal doping, we employ thermal decomposition of alkali azides, i.e. AN3 where A = K, Rb. We followed the doping procedure of thermal decomposition applied to fullerene C60.[4] A systematic variation of the superconducting transition temperature and fraction are studied as a function of alkali metal composition. [1] H. Akamatu, H. Inokuchi, and Y. Matsunaga, Nature 173 (1954) 168. [2] J. H. Sch"on, Ch. Kloc & B. Batlogg, Nature 406 (2000) 702; retraction, Nature 422 (2003) 93. [3] R. Mitsuhashi, Y. Kubozono et al.: private communication. [4] M. Tokumoto, et al. , J. Phys. Chem. Solids, 54 (1993) 1667.

  19. Smoking increases carcinogenic polycyclic aromatic hydrocarbons in human lung tissue.

    PubMed

    Goldman, R; Enewold, L; Pellizzari, E; Beach, J B; Bowman, E D; Krishnan, S S; Shields, P G

    2001-09-01

    Tobacco smoke is a major source of human exposure to polycyclic aromatic hydrocarbons (PAHs). The concentration of PAHs in lung tissue would reflect an individual's dose, and its variation could perhaps reflect cancer risk. Eleven PAHs were measured in 70 lung tissue samples from cancer-free autopsy donors by gas chromatography-mass spectrometry. There were 37 smokers and 33 nonsmokers as estimated by serum cotinine concentration. The sum of PAH concentrations was higher in smokers (P = 0.01), and there was a dose-response relationship for greater smoking (P < 0.01). Smoking increased the concentration of five PAHs including benzo(a)pyrene, which increased approximately 2-fold. The risk for increasing carcinogenic PAHs (odds ratio, 8.20; 95% confidence interval, 2.39-28.09) was 3-fold compared with noncarcinogenic PAHs (odds ratio, 2.61; 95% confidence interval, 0.75-9.12). A higher concentration of PAHs was detected in the lung tissue of males, although the estimated smoking was similar in males and females. Race was not associated with PAH concentrations overall, but PAH concentrations appeared to be higher in African-American males than in any other group. Age was weakly correlated with an increase in fluoranthene and pyrene. The measurement of PAHs in human lung tissue can be used to estimate the actual dose to the target organ.

  20. Polycyclic aromatic hydrocarbons in milk powders marketed in Uruguay.

    PubMed

    García Londoño, Víctor Alonso; Reynoso, Cora Marcela; Resnik, Silvia

    2017-12-01

    Polycyclic aromatic hydrocarbons (PAHs) occurrence in forty-four samples of milk powder, marketed in Uruguay, was determined. A high-performance liquid chromatography (HPLC) method was applied with fluorescence detector (FLD) and UV-VIS diodes array detector (DAD). Milk powder was fortified with PAHs at three levels producing average recovery higher than 78.6% for all levels. The highest concentration of benzo(a)pyrene (BaP) was 2.85 μg kg(-1) in milk powder. Contamination of samples expressed as the sum of 16 analysed PAHs varied between 5.77 and 427.28 μg kg(-1) and as PAH4 (BaP, chrysene, benzo(a)anthracene and benzo(b)fluoranthene) was between below LOD and 11.54 μg kg(-1). Only one sample exceeded the maximum limit for BaP, but 84% of the commercial milk powders did not comply with the European Union maximum limit for PAH4.

  1. Tailoring Colors by O Annulation of Polycyclic Aromatic Hydrocarbons

    PubMed Central

    Miletić, Tanja; Fermi, Andrea; Orfanos, Ioannis; Avramopoulos, Aggelos; De Leo, Federica; Demitri, Nicola; Bergamini, Giacomo; Ceroni, Paola; Papadopoulos, Manthos G.; Couris, Stelios

    2017-01-01

    Abstract The synthesis of O‐doped polyaromatic hydro‐ carbons in which two polycyclic aromatic hydrocarbon sub units are bridged through one or two O atoms has been achieved. This includes high‐yield ring‐closure key steps that, depending on the reaction conditions, result in the formation of furanyl or pyranopyranyl linkages through intramolecular C−O bond formation. Comprehensive photophysical measurements in solution showed that these compounds have exceptionally high emission yields and tunable absorption properties throughout the UV/Vis spectral region. Electrochemical investigations showed that in all cases O annulation increases the electron‐donor capabilities by raising the HOMO energy level, whereas the LUMO energy level is less affected. Moreover, third‐order nonlinear optical (NLO) measurements on solutions or thin films containing the dyes showed very good values of the second hyperpolarizability. Importantly, poly(methyl methacrylate) films containing the pyranopyranyl derivatives exhibited weak linear absorption and NLO absorption compared to the nonlinearity and NLO refraction, respectively, and thus revealed them to be exceptional organic materials for photonic devices. PMID:27897357

  2. Plant bioindicators for polycyclic aromatic hydrocarbon toxicity in aquatic microcosms

    SciTech Connect

    Gensemer, R.W.; Solomon, K.R.; Day, K.E.; Hodson, P.V.; Servos, M.R.; Greenberg, B.M.

    1994-12-31

    Plant bioindicators are being developed to assess the effects of polycyclic aromatic hydrocarbons (PAHs) in experimental aquatic ecosystems. The approach is to develop and test biomarker assays that are specifically predictive of ecological events at the population and/or community levels of organization in artificial aquatic microcosms. PAH mixtures were introduced into a series of aquatic microcosms using the wood preservative creosote as a PAH source. The authors applied creosote at five dosage levels designed to simulate conductions observed at highly contaminated sites. The growth and biomass of phytoplankton, periphyton, and macrophytes were then measured throughout the growing season, and compared to one or more biomarker assays used to detect PAH contamination. Preliminary results using fluorescence induction on aquatic macrophytes suggest that PAHs can significantly inhibit photosynthesis at even modest concentrations 1--4 hours after exposure. This assay thus is not only a sensitive indicator of PAH exposure, but may also describe mechanisms of PAH toxicity that ultimately reduce biomass or population growth for aquatic plants in these microcosms.

  3. DUSTY WINDS: EXTRAPLANAR POLYCYCLIC AROMATIC HYDROCARBON FEATURES OF NEARBY GALAXIES

    SciTech Connect

    McCormick, Alexander; Veilleux, Sylvain; Rupke, David S. N. E-mail: veilleux@astro.umd.edu

    2013-09-10

    Recent observations have shown the presence of dust and molecular material in galactic winds, but relatively little is known about the distribution of these outflow components. To shed some light on this issue, we have used IRAC images from the Spitzer Space Telescope archive to investigate polycyclic aromatic hydrocarbon (PAH) emission from a sample of 16 local galaxies with known winds. Our focus on nearby sources (median distance 8.6 Mpc) has revealed detailed PAH structure in the winds and allowed us to measure extraplanar PAH emission. We have identified extraplanar PAH features on scales of {approx}0.8-6.0 kpc. We find a nearly linear correlation between the amount of extraplanar PAH emission and the total infrared flux, a proxy for star formation activity in the disk. Our results also indicate a correlation between the height of extraplanar PAH emission and star formation rate surface density, which supports the idea of a surface density threshold on the energy or momentum injection rate for producing detectable extraplanar wind material.

  4. Risk assessment of polycyclic aromatic hydrocarbons in aquatic ecosystems.

    PubMed

    Wu, Bing; Zhang, Rui; Cheng, Shu-Pei; Ford, Timothy; Li, Ai-Min; Zhang, Xu-Xiang

    2011-07-01

    A probability risk assessment of anthracene, benzo(a)pyrene, chrysene, fluorene, phenanthrene and pyrene was carried out to examine the ecological risk of these six polycyclic aromatic hydrocarbons (PAHs) in aquatic ecosystems in China. The literature on PAH concentrations in surface water in China was collected to evaluate the environmental exposure concentrations (EEC). The 10th percentile of predicted no observed effect concentration (PNEC(10%)) of PAHs, calculated according to the data from the USEPA AQUIRE database and regulatory reviews, was applied as the toxicity assessment endpoint. The ratio of EEC and PNEC(10%), expressed as a risk quotient (RQ), was used to characterize the risk value. Bootstrapping method and Monte Carlo simulation were utilized to calculate the distribution of EEC, PNEC(10%), RQ and associated uncertainties. Risk assessment showed that reliable maximum RQs of anthracene, benzo(a)pyrene, chrysene, fluorene and phenanthrene were in the range of 0.064-0.755, lower than the acceptable value of 1. However, the reliable maximum RQ of pyrene was 1.39, indicating its potential ecological risk. Notwithstanding the uncertainty, these results suggest that the aquatic ecosystems with high PAH concentrations might pose potential ecological risks, and concerted efforts are required to ensure that surface water is protected.

  5. Mild extractability and bioavailability of polycyclic aromatic hydrocarbons in soil

    SciTech Connect

    Tang, J.; Alexander, M.

    1999-12-01

    A study was conducted to determine the relationship between bioavailability of unaged and aged polycyclic aromatic hydrocarbons (PAHs) in soil and the amounts detected by mild solvent extraction. More aged than unaged anthracene remained in Lima loam following introduction of earthworms (Eisenia foetida), a mixed culture containing anthracene-degrading microorganisms, or earthworms or wheat after bacterial biodegradation of the compound. Aging decreased the percentage of anthracene recovered by mild extraction with n-butanol from soil following introduction of earthworms, growth of wheat, biodegradation by bacteria, or when maintained sterile. Biodegradation resulted in a marked decrease in the percentage of aged and unaged anthracene recovered from soil by mild extraction with n-butanol or ethyl acetate. Aging of fluoranthene and pyrene decreased the amount removed by mild extraction with n-butanol, ethyl acetate, and propanol. The uptake of aged and unaged anthracene, fluoranthene, and pyrene by earthworms was correlated with the amounts recovered from soil by mild extraction with n-butanol, propanol, and ethyl acetate. The retention of aged and unaged anthracene by wheat and barley was correlated with the amounts recovered from soil by the same procedure. The authors suggest that mild extraction with organic solvents can be used to predict the bioavailability of PAHs in soil.

  6. Infrared Spectroscopy of Matrix-Isolated Polycyclic Aromatic Hydrocarbon Cations

    NASA Technical Reports Server (NTRS)

    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. Here the near- and mid-infrared spectra of the cations of the five most thermodynamically favored PAHs up to coronene: phenanthrene, pyrene, benzo(e)pyrene, benzo-(ghi)perylene, and coronene, are presented to test this hypothesis. For those molecules that have been studied previously (pyrene, pyrene-d(sub 10), and coronene), band positions and relative intensities are in agreement. In all of these cases we report additional features. Absolute integrated absorbance values are given for the phenanthrene, perdeuteriophenanthrene, pyrene, benzo(ghi]perylene, and coronene cations. With the exception of coronene, the cation bands corresponding to the CC modes are typically 2-5 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 that are an order of magnitude stronger than those of the neutral species, and the CH out-of-plane bends produce bands that are 5-20 times weaker than those of the neutral species. This behavior is similar to that found in most other PAH cations studied to date. The astronomical implications of these PAH cation spectra are also discussed.

  7. Surface motility of polycyclic aromatic hydrocarbon (PAH)-degrading mycobacteria.

    PubMed

    Fredslund, Line; Sniegowski, Kristel; Wick, Lukas Y; Jacobsen, Carsten S; De Mot, René; Springael, Dirk

    2008-05-01

    Surface motility of the polycyclic aromatic hydrocarbon (PAH)-degrading Mycobacterium gilvum VM552 was tested on agar and agarose plates prepared with varying amounts of gelling agents in the presence and absence of phenanthrene. Extensive spreading, originating from the point of inoculation, was observed on the surfaces of plates prepared with up to 0.3% agar and up to 0.6% agarose. The spreading velocities were 15.8 mm d(-1) on 0.3% agar and 19.5 mm d(-1) on 0.3% agarose plates. No evidence was found of accelerated or directed surface motility towards PAH crystals. The morphology of spreading M. gilvum VM552 colonies depended on both the carbon source and the type and concentration of the gelling agent. In 0.3% agar plates, M. gilvum VM552 cells were organized in 1-2-mm-wide branches of 1-5 cm length, while on agarose they slid as a homogenous monolayer across the surface. Microscopic inspection of the colonies on agar surfaces suggested that formation of branches was the combined effect of: (i) cell division and growth at the tip of a branch; (ii) propulsion of cells from the mature basal parts of a branch towards the tip; and (iii) physiologically induced reduced friction between cells and agar. Similar surface migration patterns were observed for the anthracene-degrading M. frederiksbergense LB501T.

  8. Atmospheric transport and outflow of polycyclic aromatic hydrocarbons from China

    SciTech Connect

    Chang Lang; Shu Tao; Wenxin Liu; Yanxu Zhang; Staci Simonich

    2008-07-15

    A potential receptor influence function (PRIF) model, based on air mass forward trajectory calculations, was applied to simulate the atmospheric transport and outflow of polycyclic aromatic hydrocarbons (PAHs) emitted from China. With a 10 day atmospheric transport time, most neighboring countries and regions, as well as remote regions, were influenced by PAH emissions from China. Of the total annual PAH emission of 114 Gg, 92.7% remained within the boundary of mainland China. The geographic distribution of PRIFs within China was similar to the geographic distribution of the source regions, with high values in the North China Plain, Sichuan Basin, Shanxi, and Guizhou province. The Tarim basin and Sichuan basin had unfavorable meteorological conditions for PAH outflow. Of the PAH outflow from China (8092 tons or 7.1% of the total annual PAH emission), approximately 69.9% (5655 tons) reached no further than the offshore environment of mainland China and the South China Sea. Approximate 227, 71, 746, and 131 tons PAHs reached North Korea, South Korea, Russia-Mongolia region, and Japan, respectively, 2-4 days after the emission. Only 1.4 tons PAHs reached North America after more than 9 days. Interannual variation in the eastward PAH outflow was positively correlated to cold episodes of El Nino/Southern Oscillation. However, trans-Pacific atmospheric transport of PAHs from China was correlated to Pacific North America index (PNA) which is associated with the strength and position of westerly winds. 38 refs., 4 figs.

  9. Determinants of polycyclic aromatic hydrocarbon levels in house dust.

    PubMed

    Whitehead, Todd; Metayer, Catherine; Gunier, Robert B; Ward, Mary H; Nishioka, Marcia G; Buffler, Patricia; Rappaport, Stephen M

    2011-01-01

    Estimation of human exposures to polycyclic aromatic hydrocarbons (PAHs) is often desired for the epidemiological studies of cancer. One way to obtain information about indoor levels of PAHs is to measure these chemicals in house dust. In this study, we evaluated the predictive value of self-reported and geographic data for estimating measured levels of nine PAHs in house dust from 583 households in the Northern California Childhood Leukemia Study (NCCLS). Using multivariable linear regression models, we evaluated the effects on house-dust PAH concentrations from the following covariates: residential heating sources, smoking habits, house characteristics, and outdoor emission sources. House dust was collected from 2001 to 2007, using both high-volume surface samplers and household vacuum cleaners, and was analyzed for nine PAHs using gas chromatography-mass spectrometry. All nine PAHs were detected in more than 93% of dust samples, with median concentrations ranging from 14 to 94 ng/g dust. Statistically significant effects on PAH concentrations in house dust were found for gas heating, outdoor PAH concentrations, and residence age. Yet, the optimal regression model only explained 15% of the variation in PAH levels in house dust. As self-reported data and outdoor PAH sources were only marginally predictive of observed PAH levels, we recommend that PAH concentrations be measured directly in dust samples for use in epidemiological studies.

  10. Stochastic atomistic simulation of polycyclic aromatic hydrocarbon growth in combustion.

    PubMed

    Lai, Jason Y W; Elvati, Paolo; Violi, Angela

    2014-05-07

    Nanoparticles formed in gas phase environments, such as combustion, have an important impact on society both as engineering components and hazardous pollutants. A new software package, the Stochastic Nanoparticle Simulator (SNAPS) was developed, applying a stochastic chemical kinetics methodology, to computationally investigate the growth of nanoparticle precursors through trajectories of chemical reactions. SNAPS was applied to characterize the growth of polycyclic aromatic hydrocarbons (PAHs), important precursors of carbonaceous nanoparticles and soot, in a premixed laminar benzene flame, using a concurrently developed PAH growth chemical reaction mechanism, as well as an existing benzene oxidation mechanism. Simulations of PAH ensembles successfully predicted existing experimentally measured data and provided novel insight into chemical composition and reaction pathways. The most commonly observed PAH isomers in simulations showed the importance of 5-membered rings, which contrasts with traditionally assumed compositions involving primarily pericondensed 6-membered rings. In addition, the chemical growth of PAHs involved complex sequences of highly reversible reactions, rather than relatively direct routes of additions and ring closures. Furthermore, the most common reactions involved 5-membered rings, suggesting their importance to PAH growth. The framework developed in this work will facilitate future investigation of particle inception and soot formation and will benefit engineering of novel combustion technologies to mitigate harmful emissions.

  11. Fullerenes, fulleranes and polycyclic aromatic hydrocarbons in the Allende meteorite

    NASA Technical Reports Server (NTRS)

    Becker, L.; Bunch, T. E.

    1997-01-01

    In this paper, we confirm our earlier observations of fullerenes (C60 and C70) in the Allende meteorite (Becker et al., 1994a, 1995). Fullerene C60 was also detected in two separate C-rich (approximately 0.5-1.0%) dark inclusions (Heymann et al., 1987) that were hand picked from the Allende sample. The amounts of C60 detected were approximately 5 and approximately 10 ppb, respectively, which is considerably less than what was detected in the Allende 15/21 sample (approximately 100 ppb; Becker et al., 1994a, 1995). This suggests that fullerenes are heterogeneously distributed in the meteorite. In addition, we present evidence for fulleranes, (C60Hx), detected in separate samples by laser desorption (reflectron) time-of-flight (TOF) mass spectrometry (LDMS). The LDMS spectra for the Allende extracts were remarkably similar to the spectra generated for the synthetic fullerane mixtures. Several fullerane products were synthesized using a Rh catalyst (Becker et al., 1993a) and separated using high-performance liquid chromatography (HPLC). Polycyclic aromatic hydrocarbons (PAHs) were also observed ppm levels) that included benzofluoranthene and corannulene, a cup-shaped molecule that has been proposed as a precursor molecule to the formation of fullerenes in the gas phase (Pope et al., 1993).

  12. Dusty Winds: Extraplanar Polycyclic Aromatic Hydrocarbon Features of Nearby Galaxies

    NASA Astrophysics Data System (ADS)

    McCormick, Alexander; Veilleux, Sylvain; Rupke, David S. N.

    2013-09-01

    Recent observations have shown the presence of dust and molecular material in galactic winds, but relatively little is known about the distribution of these outflow components. To shed some light on this issue, we have used IRAC images from the Spitzer Space Telescope archive to investigate polycyclic aromatic hydrocarbon (PAH) emission from a sample of 16 local galaxies with known winds. Our focus on nearby sources (median distance 8.6 Mpc) has revealed detailed PAH structure in the winds and allowed us to measure extraplanar PAH emission. We have identified extraplanar PAH features on scales of ~0.8-6.0 kpc. We find a nearly linear correlation between the amount of extraplanar PAH emission and the total infrared flux, a proxy for star formation activity in the disk. Our results also indicate a correlation between the height of extraplanar PAH emission and star formation rate surface density, which supports the idea of a surface density threshold on the energy or momentum injection rate for producing detectable extraplanar wind material.

  13. Formation History of Polycyclic Aromatic Hydrocarbons in Galaxies

    NASA Astrophysics Data System (ADS)

    Seok, J. Y.; Hirashita, H.; Asano, R.

    Polycyclic aromatic hydrocarbons (PAHs) are one of the major dust components in the interstellar medium (ISM). We present our model calculations for the PAH abundance in the ISM on a galaxy-evolution timescale. We consider shattering of carbonaceous dust grains as the formation mechanism of PAHs while the PAH abundance is reduced by coagulation onto dust grains, destruction by supernova shocks, and injection into star formation. We implement these processes in an one-zone chemical evolution model to obtain the evolution of the PAH abundance in a galaxy. We find that PAH formation becomes accelerated at a certain metallicity at which shattering becomes efficient. For PAH destruction, while supernova shock is a primary mechanism in the metal-poor environment, coagulation is dominant in the metal-rich environment. We compare the calculated PAH abundances with the observed abundances in galaxies with a wide metallicity range. Our models reproduce both the low PAH abundance in low metallicity galaxies and the metallicity-dependence of the PAH abundance in high-metallicity galaxies. We conclude that the observational trend can be explained by shattering of carbonaceous grains being the source of PAHs in the ISM.

  14. Remediation of Polycyclic Aromatic Hydrocarbons in Soil Using Cosolvent Flushing

    NASA Astrophysics Data System (ADS)

    Birak, P. S.; Hauswirth, S.; Miller, C. T.

    2010-12-01

    The ability of cosolvents to increase the solubility of hydrophobic organic contaminants has been well documented in the literature; however, few studies have examined its effectiveness with respect to field contaminated media. In this work, we examine the use of methanol flushing as a possible in-situ remediation technology using an aged, tar-contaminated field soil from a former manufactured gas plant containing polycyclic aromatic hydrocarbons (PAHs). For 15 PAHs, batch experiments were used to determine the change in the equilibrium partitioning coefficient with cosolvent fraction based on a log-linear cosolvency model. Column experiments were conducted to examine the removal of PAHs using methanol solutions as a function of pore volumes flushed. Experiments were conducted in a 25-cm long glass column. Effluent concentrations were determined for PAHs. Methanol concentrations in effluent samples were also determined. A numerical model with coupled flow and transport equations was used to predict effluent concentrations of methanol and PAHs. During cosolvent flushing with 95% methanol solutions, approximately 80% of the total PAH mass was removed in the first four pore volumes. The remaining mass in the column appeared to be mass transfer limited, particularly for the low molecular weight PAHs.

  15. Investigation of polycyclic aromatic hydrocarbons from coal gasification.

    PubMed

    Zhou, Hong-cang; Jin, Bao-sheng; Zhong, Zhao-ping; Huang, Ya-ji; Xiao, Rui; Li, Da-ji

    2005-01-01

    The hazardous organic pollutants generated from coal gasification, such as polycyclic aromatic hydrocarbons(PAHs), are highly mutagenic and carcinogenic. More researchers have paid particular attention to them. Using air and steam as gasification medium, the experiments of three kinds of coals were carried out in a bench-scale atmospheric fluidized bed gasifier. The contents of the 16 PAHs specified by US EPA in raw coal, slag, bag house coke, cyclone coke and gas were measured by HPLC to study the contents of PAHs in raw coal and the effects of the inherent characters of coals on the formation and release of PAHs in coal gasification. The experimental results showed that the distributions of PAHs in the gasified products are similar to raw coals and the total-PAHs content in coal gasification is higher than in raw coal(except Coal C). The total-PAHs contents increase and then decrease with the rise of fixed carbon and sulfur of coal while there has an opposite variation when volatile matters content increase. The quantities of PAHs reduce with the increase of ash content or the drop of heating value during coal gasification.

  16. Polycyclic aromatic hydrocarbons from wood pyrolyis in charcoal production furnaces.

    PubMed

    Barbosa, Joyce Mara dos Santos; Ré-Poppi, Nilva; Santiago-Silva, Mary

    2006-07-01

    Polycyclic aromatic hydrocarbons (PAH) were measured in smoke samples from wood carbonization during charcoal production, in both particulate matter (PM) and gaseous phases. Samples were acquired using a medium-volume air sampler at 1.5 m distance from the furnace. Particle-bound PAH were collected on Fluoropore polytetrafluoroethylene filters and gas-phase PAH were collected into sorbent tubes with XAD-2 resin. PAH were extracted with dichloromethane-methanol and analyzed using gas chromatography-mass spectrometry. The results showed total emission from the furnace of 26 microg/m3 for the 16 PAH and 2.8 microg/m3 for the 10 genotoxic PAH (from fluoranthene to benzo[g,h,i]perylene). High emission of 16 PAH in the first 8 h of wood carbonization was detected (64 microg/m3; 56% of the total emission). Associated with PM, 11% of the total emission of 16 PAH (in both phases) and 60% of 10 genotoxic PAH were found. Relative ratios (for example, [Phe]/[Phe]+[Ant]) for the PAH of the same molecular weight were obtained and compared with the published data. The concentrations of benzo[a]pyrene equivalent (BaP(eq)) were estimated using the list of toxic equivalent factors suggested by . The values of 0.30 and 0.06 mg/m3 were obtained for the total concentrations of BaP(eq) in PM and gaseous phase, respectively.

  17. Polycyclic Aromatic Hydrocarbons in drinking water of Tehran, Iran.

    PubMed

    Karyab, Hamid; Yunesian, Masud; Nasseri, Simin; Mahvi, Amir Hosein; Ahmadkhaniha, Reza; Rastkari, Noushin; Nabizadeh, Ramin

    2013-08-05

    Distribution and seasonal variation of sixteen priority polycyclic aromatic hydrocarbons (PAHs) were investigated in the drinking water of Tehran, the capital of Iran. Detected single and total PAHs concentrations were in the range of 2.01-38.96 and 32.45-733.10 ng/L, respectively, which were quite high compared to the values recorded in other areas of the world. The average occurrence of PAHs with high molecular weights was 79.55%; for example, chrysene occurred in 60.6% of the samples, with a maximum concentration of 438.96 ng/L. In addition, mean carcinogen to non-carcinogen PAHs ratio was 63.84. Although the concentration of benzo[a]pyrene, as an indicator of water pollution to PAHs, was lower than the guideline value proposed by World Health Organization (WHO) as well as that of Iranian National Drinking Water Standards for all of the samples, the obtained results indicated that carcinogen PAHs present in the drinking water of Tehran can cause threats to human health.

  18. Fugacity analysis of polycyclic aromatic hydrocarbons between microplastics and seawater

    NASA Astrophysics Data System (ADS)

    Lee, Hwang; Chang, Sein; Kim, Seung-Kyu; Kwon, Jung-Hwan

    2017-01-01

    Recently, the accumulation of plastic debris in the marine environment has become a great concern worldwide. Although plastics are biologically and chemically inert, plastic debris has been suspected of causing adverse effects on ecosystems due to the increase in reactivity by size reduction and/or micropollutants associated with plastics. Because of the high sorption capacity of microplastics toward organic micropollutants, it is suspected that microplastics may play roles in the distribution and fate of micropollutants. In order to quantitatively evaluate the "net flow" of environmental contaminants in water-plastic-organism systems, a fugacity analysis was conducted using concentrations of polycyclic aromatic hydrocarbons (PAHs) in open oceans and in polyethylene as a representative material of plastic debris. Ratio of fugacity in polyethylene to that in seawater showed a decreasing trend with increasing partition coefficient between polyethylene and seawater (KPE/sw). This indicates that phase equilibrium between polyethylene and seawater is not attained for higher molecular weight PAHs. Disequilibrium of high molecular weight PAHs suggests that transfer from seawater to plastic debris is thermodynamically driven and the role of plastic debris as a vector to transfer them to living organisms would be minimal. However, additives may slowly migrate from plastics into the environment causing potentially serious effects on ecosystems.

  19. Molecular Spectroscopy in Astrophysics: The Case of Polycyclic Aromatic Hydrocarbons

    NASA Technical Reports Server (NTRS)

    Salama, Farid; DeVincent, Donald L. (Technical Monitor)

    2000-01-01

    The role of molecular spectroscopy in astrophysics and astrochemistry is discussed in the context of the study of large, complex, carbon-bearing molecules, namely, Polycyclic Aromatic Hydrocarbons or PAHs. These molecular species are now thought to be widespread in the interstellar medium in their neutral and ionized forms. Identifying the carriers responsible for unidentified interstellar spectral bands will allow to derive important information on cosmic elemental abundances as well as information on the physical conditions (density, temperature) reigning in specific interstellar environments. These, in turn, are key elements for a correct understanding of the energetic mechanisms that govern the origin and the evolution of the interstellar medium. A multidisciplinary approach - combining astronomical observations with laboratory simulations and theoretical modeling - is required to address these complex issues. Laboratory spectra of several PAHs, isolated at low temperature in inert gas matrices or seeded in a supersonic jet expansion, are discussed here and compared to the astronomical spectra of reddened, early type, stars. The electronic spectroscopy of PAHs in the ultraviolet, visible, and near-infrared domains is reviewed and an assessment of the potential contribution of PAHs to the interstellar extinction in the ultraviolet and in the visible is discussed.

  20. Polycyclic aromatic hydrocarbons in household dust near diesel transport routes.

    PubMed

    Kuo, Chung-Yih; Chen, Heng-Chun; Cheng, Fang-Ching; Huang, Li-Ru; Chien, Po-Shan; Wang, Jing-Ya

    2012-02-01

    A river-dredging project has been undertaken in Nantou, Taiwan. A large number of diesel vehicles carrying gravel and sand shuttle back and forth on the main roads. Ten stations along major thoroughfares were selected as the exposure sites for testing, while a small village located about 9 km from a main traffic route was selected as the control site. Levels of household dust loading at the exposure sites (60.3 mg/m(2)) were significantly higher than those at the control site (38.2 mg/m(2)). The loading (μg/m(2)) of t-PAHs (total polycyclic aromatic hydrocarbons) in the household dust at the exposure sites was significantly higher (P < 0.05) than was the case at the control site. The diagnostic ratios of PAHs showed that diesel emissions were the dominant source of PAHs at the exposure sites. The lack of a significant correlation between the concentrations of Fe and t-PAHs suggested that the t-PAHs in household dust might come from diverse sources. However, a significant correlation (P = 0.003) between the concentrations of Mo and t-PAHs implied that the most of the t-PAHs in the household dust might have resulted from diesel emissions. The lifetime cancer risks of BaP(eq) from household dust exposure were markedly higher than those resulting from inhalation exposure. © Springer Science+Business Media B.V. 2011

  1. Polycyclic aromatic hydrocarbon ions and the diffuse interstellar bands

    NASA Technical Reports Server (NTRS)

    Salama, F.; Allamandola, L. J.

    1995-01-01

    Neutral naphthalene (C10H8), phenanthrene (C14H10), and pyrene (C16H10) absorb strongly in the ultraviolet and may contribute to the extinction curve. High abundances are required to produce detectable structures. The cations of these Polycyclic Aromatic Hydrocarbons (PAHs) absorb in the visible. C10H8(+) has 12 discrete absorption bands which fall between 6800 and 5000 A. The strongest band at 6741 A falls close to the weak 6742 A diffuse interstellar band (DIB). Five other weaker bands also match DIBs. The possibility that C10H8(+) is responsible for some of the DIBs can be tested by searching for new DIBS at 6520, 6151, and 5965 A, other moderately strong naphthalene cation band positions. If C10H8(+) is indeed responsible for the 6742 A feature, it accounts for 0.3% of the cosmic carbon. The spectrum of C16H10(+) is dominated by a strong band at 4435 A in an Ar matrix and 4395 A in a Ne matrix, a position which falls very close to the strongest DIB, that at 4430 A. If C16H10(+), or a closely related pyrene-like ion is indeed responsible for the 4430 A feature, it accounts for 0.2% of the cosmic carbon. We also report an intense, very broad UV-to-visible continuum which is associated with both ions and could explain how PAHs convert interstellar UV and visible radiation into IR.

  2. Polycyclic Aromatic Hydrocarbon Ionization Energy Lowering in Water Ices

    NASA Technical Reports Server (NTRS)

    Gudipati, Murthy S.; Allamandola, Louis J.

    2004-01-01

    In studying various interstellar and solar system ice analogs, we have recently found that upon vacuum ultraviolet photolysis, polycyclic aromatic hydrocarbons (PAHs) frozen in water ice at low temperatures are easily ionized and indefinitely stabilized as trapped ions (Gudipati; Gudipati & Allamandola). Here we report the first experimental study that shows that PAH ionization energy is significantly lowered in PAH/H2O ices, in agreement with recent theoretical work (Woon & Park). The ionization energy (IE) of the PAH studied here, quaterrylene (C40H20, IE = 6.11 eV), is lowered by up to 2.11 eV in water ice. PAH ionization energy reduction in low-temperature water ice substantially expands the astronomical regions in which trapped ions and electrons may be important. This reduction in ionization energy should also hold for other types of trapped species in waterrich interstellar, circumstellar, and solar system ices. Subject headings: ISM: clouds - methods: laboratory - molecular processes - radiation mechanisms: nonthermal -ultraviolet: ISM - ultraviolet: solar system

  3. Cardiac Autonomic Dysfunction from Occupational Exposure to Polycyclic Aromatic Hydrocarbons

    PubMed Central

    Lee, Mi-Sun; Magari, Shannon; Christiani, David C.

    2013-01-01

    Objectives Polycyclic aromatic hydrocarbons (PAHs) exposures have been associated with cardiopulmonary mortality and cardiovascular events. This study investigated the association between a biological marker of PAHs exposure, assessed by urinary 1-hydroxypyrene (1-OHP), and heart rate variability (HRV) in an occupational cohort of boilermakers. Methods Continuous 24-hour monitoring of the ambulatory electrocardiogram (ECG) and pre and post shift urinary 1-OHP were repeated over extended periods of the work week. Mixed effects models were fit for the 5-minute standard deviation of normal-to-normal intervals (SDNN) in relation to urinary 1-OHP levels pre and post workshift on the day they wore the monitor, controlling for potential confounders. Results We found a significant decrease in 5-min SDNN during work of −13.6% (95% confidence interval, −17.2% to −9.8%) for every standard deviation (0.53 microgram/gram [μg/g] creatinine) increase in the next-morning pre-shift 1-OHP levels. The magnitude of reduction in 5-min SDNN were largest during the late night period after work and increased with every standard deviation (0.46 μg/g creatinine) increase in post-shift 1-OHP levels. Conclusion This is the first report providing evidence that occupational exposure to PAHs is associated with altered cardiac autonomic function. Acute exposure to PAHs may be an important predictor of cardiovascular disease risk in the work environment. PMID:21172795

  4. A critical review of polycyclic aromatic hydrocarbon phototoxicity models.

    PubMed

    Marzooghi, Solmaz; Di Toro, Dominic M

    2016-12-24

    Polycyclic aromatic hydrocarbons (PAHs) are known to exhibit photo-induced toxicity. Hundreds to thousands of PAH parent and substituted compounds are found in the environment, and developing a predictive model applicable to a wide variety of PAHs and organisms is a necessary precursor to environmental risk assessments. There has been evolutionary progress in phototoxicity modeling since 1977. In the present study, a comprehensive review of the models developed to predict phototoxicity of PAHs is presented. The contributions of each of the models to the state of the art are discussed. The models are compared in terms of their scope of applicability to different organisms, PAHs, endpoints (median lethal time and median lethal concentration), and light conditions. The current state of the science that accounts for the key elements of phototoxicity modeling, including the differences in species sensitivity, the partitioning of PAHs into the target lipid of the organisms, and light absorption by the chemicals, as well as light exposure time and conditions, is discussed. In addition, the remaining issues that need to be addressed are explored: the effect of time-varying exposures to light and PAH concentrations, and the lack of a mechanistic understanding that can explain the failure of the Bunsen-Roscoe law of reciprocity. Environ Toxicol Chem 2016;9999:1-11. © 2016 SETAC.

  5. Fugacity analysis of polycyclic aromatic hydrocarbons between microplastics and seawater

    NASA Astrophysics Data System (ADS)

    Lee, Hwang; Chang, Sein; Kim, Seung-Kyu; Kwon, Jung-Hwan

    2017-03-01

    Recently, the accumulation of plastic debris in the marine environment has become a great concern worldwide. Although plastics are biologically and chemically inert, plastic debris has been suspected of causing adverse effects on ecosystems due to the increase in reactivity by size reduction and/or micropollutants associated with plastics. Because of the high sorption capacity of microplastics toward organic micropollutants, it is suspected that microplastics may play roles in the distribution and fate of micropollutants. In order to quantitatively evaluate the "net flow" of environmental contaminants in water-plastic-organism systems, a fugacity analysis was conducted using concentrations of polycyclic aromatic hydrocarbons (PAHs) in open oceans and in polyethylene as a representative material of plastic debris. Ratio of fugacity in polyethylene to that in seawater showed a decreasing trend with increasing partition coefficient between polyethylene and seawater (KPE/sw). This indicates that phase equilibrium between polyethylene and seawater is not attained for higher molecular weight PAHs. Disequilibrium of high molecular weight PAHs suggests that transfer from seawater to plastic debris is thermodynamically driven and the role of plastic debris as a vector to transfer them to living organisms would be minimal. However, additives may slowly migrate from plastics into the environment causing potentially serious effects on ecosystems.

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

    PubMed

    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.

  7. Polycyclic Aromatic Hydrocarbons Transformations in an Urban Fog

    NASA Astrophysics Data System (ADS)

    Valsaraj, K.; Wornat, M. J.; Chen, J.; Ehrenhauser, F.

    2010-07-01

    Polycyclic aromatic hydrocarbons (PAHs) are generated from incomplete combustion of fuels, coal-fired power plants and other anthropogenic activities. These are ubiquitous in all environments, especially the atmosphere. PAHs generally are found in the gaseous form and associated with the particles in the atmosphere. They are also found in the atmospheric water present in the form of fog, mist, rain, snow and ice. Particles (aerosols) in the atmosphere invariably contain a thin film of water which tends to have a high affinity for the adsorption of gaseous PAHs. Molecular dynamic simulations clearly show that the air-water interface is a preferable surface for adsorption of large molecular weight PAHs and atmospheric oxidants (e.g., O3, OH, 1O2, NO3). Thus, photochemical transformation of adsorbed PAHs in fog droplets is a possibility in the atmosphere. This could lead to the formation of water-soluble oxy-PAHs which are potential precursors for secondary organic aerosols (SOAs). Field work in Baton Rouge and Houston combined with laboratory work in thin film reactors have shown that this hypothesis is substantially correct. Field data on fog and aerosols (pre- and post-fog) will be enumerated. Laboratory work and their implications will be summarized. The thin film surface environment resulted in enhanced reaction kinetics compared to bulk phase kinetics. The influence of surface reactions on the product compositions is evaluated by performing experiments with different film thicknesses.

  8. Genotoxicity of model and complex mixtures of polycyclic aromatic hydrocarbons

    SciTech Connect

    Donnelly, K.C.; Phillips, T.D.; Onufrock, A.M.; Collie, S.L.; Huebner, H.J.; Washburn, K.S.

    1996-12-31

    Polycyclic aromatic hydrocarbons (PAHs) are one of the most ubiquitous classes of environmental carcinogens; however, limited information is available to describe their potential genotoxic interactions. This manuscript reports on the interactions of PAHs in complex mixtures as determined in microbial mutagenicity assays. Samples analyzed included separate 2-, 3-, and 4-ring PAH individual model fractions (IMFs) constructed to simulate the composition of a model coal tar. These were tested individually and in various combinations, including a reconstituted model fraction (RMF) composed of all three IMFs. A solvent extract of coal tar and a benzo(a)pyrene-amended extract of coal tar were also tested. The maximum mutagenic response of 1,089 revertants was induced by the RMF at a dose of 90 {micro}g/plate with metabolic activation. At the four lowest dose levels, the response observed in the RMF sample was increased when compared to the 4-ring-IMF sample alone. However, the response observed with the RMF sample at the highest dose tested was less than was observed in the 4-ring-IMF sample tested independently. When IMF samples were combined or mixed with individual chemicals, some inhibition was observed. These data indicate that mixtures of PAHs can exhibit a variety of mutagenic interactions controlled by both the metabolism of the PAHs and by their concentration in the mixture.

  9. Polycyclic aromatic hydrocarbons: levels and phase distributions in preschool microenvironment.

    PubMed

    Oliveira, M; Slezakova, K; Delerue-Matos, C; Pereira, M C; Morais, S

    2015-10-01

    This work aims to characterize levels and phase distribution of polycyclic aromatic hydrocarbons (PAHs) in indoor air of preschool environment and to assess the impact of outdoor PAH emissions to indoor environment. Gaseous and particulate (PM1 and PM(2.5)) PAHs (16 USEPA priority pollutants, plus dibenzo[a,l]pyrene, and benzo[j]fluoranthene) were concurrently sampled indoors and outdoors in one urban preschool located in north of Portugal for 35 days. The total concentration of 18 PAHs (ΣPAHs) in indoor air ranged from 19.5 to 82.0 ng/m(3) ; gaseous compounds (range of 14.1-66.1 ng/m(3)) accounted for 85% ΣPAHs. Particulate PAHs (range 0.7-15.9 ng/m(3)) were predominantly associated with PM1 (76% particulate ΣPAHs) with 5-ring PAHs being the most abundant. Mean indoor/outdoor ratios (I/O) of individual PAHs indicated that outdoor emissions significantly contributed to PAH indoors; emissions from motor vehicles and fuel burning were the major sources. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  10. Polycyclic aromatic hydrocarbon adsorption on selected solid particulate matter fractions

    NASA Astrophysics Data System (ADS)

    Bozek, Frantisek; Huzlik, Jiri; Pawelczyk, Adam; Hoza, Ignac; Naplavova, Magdalena; Jedlicka, Jiri

    2016-02-01

    This article is directed to evaluating the proportion of polycyclic aromatic hydrocarbons (PAHs) captured on particulate matter (PM) classified as PM2.5-10 and PM2.5, i.e. particulate matter of aerodynamic diameter 2.5-10 μm and 2.5 μm. During three week-long and one 2-day campaigns, 22 paired air samples were taken in parallel of PM10 and PM2.5 fractions inside the Mrázovka tunnel in Prague, Czech Republic. Following sample preparation, concentrations of individual PAHs were determined using gas chromatography combined with mass spectrometry. Concentrations of individual pairs of each PAH were tested by the nonparametric method using Spearman's rank correlation coefficient. At significance level p < 0.01, it was demonstrated that all individual PAHs, including their totals, were bound to the PM2.5 fraction. Exceptions were seen in the cases of acenaphthylene, acenaphthene, and indeno[1,2,3-cd]pyrene, the concentrations of which fluctuated around the detection limit, where increased measurement error can be expected.

  11. Polycyclic Aromatic Hydrocarbons in drinking water of Tehran, Iran

    PubMed Central

    2013-01-01

    Distribution and seasonal variation of sixteen priority polycyclic aromatic hydrocarbons (PAHs) were investigated in the drinking water of Tehran, the capital of Iran. Detected single and total PAHs concentrations were in the range of 2.01-38.96 and 32.45-733.10 ng/L, respectively, which were quite high compared to the values recorded in other areas of the world. The average occurrence of PAHs with high molecular weights was 79.55%; for example, chrysene occurred in 60.6% of the samples, with a maximum concentration of 438.96 ng/L. In addition, mean carcinogen to non-carcinogen PAHs ratio was 63.84. Although the concentration of benzo[a]pyrene, as an indicator of water pollution to PAHs, was lower than the guideline value proposed by World Health Organization (WHO) as well as that of Iranian National Drinking Water Standards for all of the samples, the obtained results indicated that carcinogen PAHs present in the drinking water of Tehran can cause threats to human health. PMID:24499505

  12. Polycyclic aromatic hydrocarbons and pesticides in milk powder.

    PubMed

    Dobrinas, Simona; Soceanu, Alina; Popescu, Viorica; Coatu, Valentina

    2016-05-01

    This Research Communication reports analysis of 37 compounds comprising polycyclic aromatic hydrocarbons (PAHs), organochlorine and organophosphate pesticides (OCPS and OPPS) in milk powder (one brand each of commercial infant formulae, follow-on formulae and baby formulae purchased from a local supermarket in Romania). The selected analytes were investigated using gas chromatography-mass spectrometry (GC-MS), gas chromatography with electron capture detector (GC-ECD) and gas chromatography with thermionic sensitive detection (GC-TSD). The estimated limits of detection for most target analytes were in the μg/kg level (range 0·001-0·320 µg/kg). The purpose of the study was to determine the selected analytes, to assess the exposure of babies and infants and to produce data for comparison with tolerable limits according to the European Union Regulations. In most of the samples the organochlorine pesticides values were under the limit of detection. Exceptions were heptachlor epoxide and endosulfan sulphate, the last of which was found in all analysed samples at low concentrations. We also found detectable levels of ethoprophos, parathion-methyl, chlorpyrifos, prothiofos, guthion, disulfoton and fenchlorphos in most of the analysed samples. Benzo[a]pyrene, which is used as an indicator for the presence of PAHs, was not detected in selected samples. The low level of exposure to contaminants indicates that there are no health risks for the infants and babies that consume this brand of milk powder formulae.

  13. Sources of polycyclic aromatic hydrocarbons to the Hudson River Airshed

    NASA Astrophysics Data System (ADS)

    Lee, Jong Hoon; Gigliotti, Cari L.; Offenberg, John H.; Eisenreich, Steven J.; Turpin, Barbara J.

    2004-11-01

    Sources of polycyclic aromatic hydrocarbons (PAHs) to the Hudson River Estuary Airshed were investigated using positive matrix factorization (PMF). A three-city dataset was used to obtain common factor profiles. The contributions of each factor on each sampling day and site were then determined, and a sensitivity analysis was conducted. A stable eight-factor solution was identified. PMF was able to identify a factor associated with air-surface exchange. This factor contains low-molecular weight PAHs and was a dominant contributor to the measured PAHs concentrations. Factors linked to motor vehicle use (diesel and gasoline vehicle emissions and evaporative/uncombusted petroleum) and natural gas combustion were also major contributors. Motor vehicle combustion and oil combustion factors were the predominant contributors to particle-phase PAHs, while natural gas combustion, air-surface exchange, and evaporative/uncombusted petroleum factors made substantial contributions to gas-phase PAH concentrations. In contrast to fine particulate matter (PM2.5), which is dominated by regional transport, spatial variations in PAH concentrations suggest that PAH concentrations in the Hudson River Estuary Airshed are dominated by sources within the New York-New Jersey urban-industrial complex.

  14. Polycyclic Aromatic Hydrocarbons as Star Formation Rate Indicators

    NASA Astrophysics Data System (ADS)

    Calzetti, D.

    2011-03-01

    As images and spectra from ISO and Spitzer have provided increasingly higher-fidelity representations of the mid-infrared (MIR) and Polycyclic Aromatic Hydrocarbon (PAH) emission from galaxies and galactic and extra-galactic regions, more systematic efforts have been devoted to establishing whether the emission in this wavelength region can be used as a reliable star formation rate indicator. This has also been in response to the extensive surveys of distant galaxies that have accumulated during the cold phase of the Spitzer Space Telescope. Results so far have been somewhat contradictory, reflecting the complex nature of the PAHs and of the mid-infrared-emitting dust in general. The two main problems faced when attempting to define a star formation rate indicator based on the mid-infrared emission from galaxies and star-forming regions are: (1) the strong dependence of the PAH emission on metallicity; (2) the heating of the PAH dust by evolved stellar populations unrelated to the current star formation. I review the status of the field, with a specific focus on these two problems, and will try to quantify the impact of each on calibrations of the mid-infrared emission as a star formation rate indicator.

  15. Polycyclic aromatic hydrocarbons and metals in snow along a highway.

    PubMed

    Reinosdotter, K; Viklander, M; Malmqvist, P A

    2006-01-01

    Snow quality and its variations due to distance from the road were studied. Also, how the snow quality changes over time during the melting period was discussed. Snow samples were collected at three occasions during the winter of 2004. The samples were taken along a highway in the Luleå region, Sweden, with an average daily traffic load of 9200 vehicles. Snow samples were taken perpendicular to the road and at different distances. The snow samples were analysed for metals and polycyclic aromatic hydrocarbons (PAH). Also, weather parameters such as temperature, precipitation, and wind speed and wind direction were measured. The highest total metal and PAH concentrations were found at the sample site closest to the road and at the end of the season. Before the melting period started, 42-57% of the total amount of metals and PAH were found in the first 1 m of the snow pack. This information could be valuable when one is discussing how to achieve sustainable snow-handling management.

  16. Outflow of polycyclic aromatic hydrocarbons from Guangdong, southern China.

    PubMed

    Lang, Chang; Tao, Shu; Zhang, Gang; Fu, Jiamo; Simonich, Staci

    2007-12-15

    The atmospheric outflow of polycyclic aromatic hydrocarbons (PAHs) from Guangdong, China, a region of high PAH emission, was modeled using a potential receptor influence function (PRIF) probabilistic model which was based on a spatially resolved PAH inventory and air mass forward-trajectory calculations. Photochemical degradation and deposition (dry and wet) of PAHs during atmospheric transport were taken into consideration. On average, 48% of the PAHs (by mass) remained in the atmosphere for a transport period of 5 days, staying within the boundary of the source region. The medium molecular weight PAHs (four rings) were predicted to travel longer distances in the atmosphere than the low (three rings) or high molecular weight PAHs (five rings) because they are less photodegradable than the lower molecular weight, gas-phase PAHs and less likelyto undergo wet and dry depositions than the higher molecular weight, particulate phase PAHs. Under the strong influence of the East Asian monsoons in winter, the predominant outflow pattern of PAHs from Guangdong was to the South China Sea and Southeast Asian countries. In summer, PAHs were transported primarily to northern mainland China. Under particular weather conditions in winter, the PAH-containing air masses were lifted by cold fronts or convection and transported toward the Pacific Ocean by westerly winds. In addition to the distinct seasonality in PAH dispersion and outflow, interannual long-term variation in the outflow is likely influenced by El Niño and southern oscillation.

  17. Bioaccessibility of polycyclic aromatic hydrocarbons: relevance to toxicity and carcinogenesis

    PubMed Central

    Harris, Kelly L; Banks, Leah D; Mantey, Jane A; Huderson, Ashley C; Ramesh, Aramandla

    2014-01-01

    Introduction Bioaccessibility is a growing area of research in the field of risk assessment. As polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants, they are the toxicants of focus to establish cancer risks in humans. Orally ingested PAHs also cause toxicity and even affect the pharmacokinetic behavior of some therapeutic agents. Toward this end, bioaccessibility is being used as a tool to assess the risk of PAHs via dietary exposures. Areas covered This review covers some in vitro bioaccessibility models for PAHs that have been used for the past one-and-a-half decade. This review also considers the factors that influence bioaccessibility and debates the merits and limitations of using a bioaccessibility concept for estimating risk from ingestion of PAH-contaminated soil and food. Finally, the authors discuss the implications of bioaccessibility for PAH-induced toxicity and cancers in the context of risk assessment. Expert opinion So far, much of the focus on PAH bioaccessibility is centered on soil as a preferential matrix. However, ingestion of PAHs through diet far exceeds the amount accidentally ingested through soil. Therefore, bioaccessibility could be exploited as a tool to assess the relative risk of various dietary ingredients tainted with PAHs. While bioaccessibility is a promising approach for assessing PAH risk arising from various types of contaminated soils, none of the models proposed appears to be valid. Bioaccessibility values, derived from in vitro studies, still require validation from in vivo studies. PMID:23898780

  18. Atmospheric polycyclic aromatic hydrocarbons: Source attribution, emission factors and regulation

    NASA Astrophysics Data System (ADS)

    Ravindra, Khaiwal; Sokhi, Ranjeet; Van Grieken, René

    There is an increasing concern about the occurrence of polycyclic aromatic hydrocarbons (PAHs) in the environment as they are ubiquitous in ambient air and some of them are among the strongest known carcinogens. PAHs and their derivatives are produced by the incomplete combustion of organic material arising, partly, from natural combustion such as forest and volcanic eruption, but with the majority due to anthropogenic emissions. The PAH concentration varies significantly in various rural and urban environments and is mainly influenced by vehicular and domestic emissions. The review serves as a database to identify and characterize the emission sources of PAHs and hence various approaches including diagnostic ratio (DR) and principal component analysis (PCA) are discussed in detail. These approaches allow individual PAHs to be associated with their origin sources. The factors that effect PAH emission and estimated emission rate are also discussed in this paper. Although the levels of low molecular weight PAHs are high in vapor phase, most of the probable human carcinogenic PAHs are found to be associated with particulate matter, especially in fine mode particles in ambient air. Many countries have proposed a non-mandatory concentration limit for PAHs, whereas the health risk studies conducted in relation to PAH exposure, urge that these pollutants should be given a high priority when considering air quality management and reduction of impacts.

  19. Vibrational spectroscopic study of vinyl substituted polycyclic aromatic hydrocarbons.

    PubMed

    Maurya, Anju; Rastogi, Shantanu

    2015-12-05

    The mid infrared emission features observed in various astrophysical sources are attributed to polycyclic aromatic hydrocarbon (PAH) molecules. The models of emission spectra from a collection of PAHs show uncertainty in matching the 6.2 μm feature. This indicates the need to consider a larger variety of PAHs and PAH derivatives. Chemical pathways towards formation of PAHs in the astrophysical environments involve vinyl substituted PAHs as intermediate products. Vibrational spectroscopic study of vinyl-PAHs is reported in the present work. The vinyl group is substituted at similar positions in eight different PAHs. The obtained optimized structures show that vinyl substitution at 2 position in acenes gives planar geometry, while all other vinyl-PAHs are non-planar. Infrared spectra is simulated for neutrals as well as for cations. The results are compared with the spectra of corresponding plain PAHs and analyzed for possible match with astrophysical observations. New features, due to vinyl group in the composite spectra, identified at 6.64, 6.92, 7.27, 8.77 and 10.35 μm fall close to some sub features of the observed emission spectra. The paper provides data that may be used in the emission models particularly along proto planetary nebulae type cool objects. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Distribution of polycyclic aromatic hydrocarbons in coke plant wastewater.

    PubMed

    Burmistrz, Piotr; Burmistrz, Michał

    2013-01-01

    The subject of examinations presented in this paper is the distribution of polycyclic aromatic hydrocarbons (PAHs) between solid and liquid phases in samples of raw wastewater and wastewater after treatment. The content of 16 PAHs according to the US EPA was determined in the samples of coke plant wastewater from the Zdzieszowice Coke Plant, Poland. The samples contained raw wastewater, wastewater after physico-chemical treatment as well as after biological treatment. The ΣPHA16 content varied between 255.050 μg L(-1) and 311.907 μg L(-1) in raw wastewater and between 0.940 and 4.465 μg L(-1) in wastewater after full treatment. Investigation of the distribution of PAHs showed that 71-84% of these compounds is adsorbed on the surface of suspended solids and 16-29% is dissolved in water. Distribution of individual PAHs and ΣPHA16 between solid phase and liquid phase was described with the use of statistically significant, linear equations. The calculated values of the partitioning coefficient Kp changed from 0.99 to 7.90 for naphthalene in samples containing mineral-organic suspension and acenaphthylene in samples with biological activated sludge, respectively.

  1. Particle-bound polycyclic aromatic hydrocarbon concentrations in transportation microenvironments

    NASA Astrophysics Data System (ADS)

    Houston, Douglas; Wu, Jun; Yang, Dongwoo; Jaimes, Guillermo

    2013-06-01

    This study is one of the first case studies to characterize the exposure of urban residents to traffic-related air pollution across locations and transportation microenvironments during everyday activities. Twenty-four adult residents of Boyle Heights, a neighborhood near downtown Los Angeles, carried a portable air pollution monitor and a Global Positioning Systems (GPS) tracking device for a total of 96 days. We found significant spatial and temporal variation in the particle-bound polycyclic aromatic hydrocarbon (pPAH) concentrations in transportation microenvironments. Average pPAH concentrations were higher while walking outdoors (190 ng m-3) compared to traveling in private passenger vehicles (138-155 ng m-3) or traveling in public transportation (61-124 ng m-3). Although travel comprised 5% of participant days, it was associated with 27% of overall daily pPAH exposure. Regression models explained 40-55% of the variation in daily average pPAH concentrations, and 40-44% of the variation in 1-min interval concentrations. Important factors included time spent traveling, travel speed, meteorological and nearby land use factors, time of day, and proximity to roadways. Although future research is needed to develop stronger predictive models, our study demonstrates portable tracking devices can provide a more complete, diurnal characterization of air pollution exposures for urban populations.

  2. Absorption Spectroscopy of Polycyclic Aromatic Hydrocarbons under Interstellar Conditions

    NASA Technical Reports Server (NTRS)

    Stone, Bradley M.

    1996-01-01

    The presence and importance of polycyclic aromatic hydrocarbons (PAHs, a large family of organic compounds containing carbon and hydrogen) in the interstellar medium has already been well established. The Astrochemistry Laboratory at NASA Ames Research Center (under the direction of Louis Allamandola and Scott Sandford) has been the center of pioneering work in performing spectroscopy on these molecules under simulated interstellar conditions, and consequently in the identification of these species in the interstellar medium by comparison to astronomically obtained spectra. My project this summer was twofold: (1) We planned on obtaining absorption spectra of a number of PAHs and their cations in cold (4K) Ne matrices. The purpose of these experiments was to increase the number of different PAHs for which laboratory spectra have been obtained under these simulated interstellar conditions; and (2) I was to continue the planning and design of a new laser facility that is being established in the Astrochemistry laboratory. The laser-based experimental set-up will greatly enhance our capability in examining this astrophysically important class of compounds.

  3. Isoxazolidinyl polycyclic aromatic hydrocarbons as DNA-intercalating antitumor agents.

    PubMed

    Rescifina, Antonio; Chiacchio, Ugo; Corsaro, Antonino; Piperno, Anna; Romeo, Roberto

    2011-01-01

    The second generation and an isosteric series of isoxazolidinyl polycyclic aromatic hydrocarbons, as DNA-intercalator agents designed to act on remotely implanted tumors, have been synthesized in good yields according to the 1,3-dipolar cycloaddition methodology. The structure of the obtained cycloadducts has been determined by NOE experiments and supported by computational studies at PM3 level. The utility of this new template in the synthesis of structures designed to capitalize on its intercalative properties has been examined. All the obtained compounds have been tested for their in vitro cytotoxic activity and the most potent of them showed an IC(50) of 9 μM upon the human lung cancer (A-549) cell and a binding constant, for the intercalation with calf thymus DNA, of 9.6 × 10(4) M(-1). Biological and docking studies showed that these compounds complex exclusively by intercalation between base pairs, approaching the DNA from its minor groove, with a neat selectivity for the AT or GC nucleobases. Copyright © 2010 Elsevier Masson SAS. All rights reserved.

  4. Novel isoxazole polycyclic aromatic hydrocarbons as DNA-intercalating agents.

    PubMed

    Rescifina, Antonio; Varrica, Maria Giulia; Carnovale, Caterina; Romeo, Giovanni; Chiacchio, Ugo

    2012-05-01

    The third generation of isoxazole polycyclic aromatic hydrocarbons, acting as DNA-intercalator agents and possessing the binding constants in the range 10(4)-10(5) M(-1), in order to easily diffuse targeting remotely implanted tumors, has been synthesized in good yields according to the 1,3-dipolar cycloaddition methodology. The structure of the obtained cycloadducts has been determined by NOE experiments and supported by computational studies at PM3 level. All the obtained compounds have been tested for their in vitro cytotoxic activity and the most potent of them, (3RS,5SR)-2-benzyl-N,N-dimethyl-3-(pyren-1-yl)isoxazolidine-5-carboxamide (7d), showed an IC(50) of 4 μM upon the human lung cancer (A-549) cells. Moreover, compound 7d showed binding constant for the intercalation with calf thymus DNA, poly-d(AT)(2) and poly-d(GC)(2) of 1.7 × 10(5) M(-1), 1.6 × 10(5) M(-1) and 0.3 × 10(5) M(-1), respectively. Biological and docking studies showed that, in vitro, these compounds complex by intercalation between base pairs, approaching the DNA from its minor groove with a preference for the AT nucleobases pairs. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  5. New insights into thermal decomposition of polycyclic aromatic hydrocarbon oxyradicals.

    PubMed

    Liu, Peng; Lin, He; Yang, Yang; Shao, Can; Gu, Chen; Huang, Zhen

    2014-12-04

    Thermal decompositions of polycyclic aromatic hydrocarbon (PAH) oxyradicals on various surface sites including five-membered ring, free-edge, zigzag, and armchair have been systematically investigated by using ab initio density functional theory B3LYP/6-311+G(d,p) basis set. The calculation based on Hückel theory indicates that PAHs (3H-cydopenta[a]anthracene oxyradical) with oxyradicals on a five-membered ring site have high chemical reactivity. The rate coefficients of PAH oxyradical decomposition were evaluated by using Rice-Ramsperger-Kassel-Marcus theory and solving the master equations in the temperature range of 1500-2500 K and the pressure range of 0.1-10 atm. The kinetic calculations revealed that the rate coefficients of PAH oxyradical decomposition are temperature-, pressure-, and surface site-dependent, and the oxyradical on a five-membered ring is easier to decompose than that on a six-membered ring. Four-membered rings were found in decomposition of the five-membered ring, and a new reaction channel of PAH evolution involving four-membered rings is recommended.

  6. Polycyclic aromatic hydrocarbons in stormwater runoff from sealcoated pavements.

    PubMed

    Watts, Alison W; Ballestero, Thomas P; Roseen, Robert M; Houle, James P

    2010-12-01

    Coal-tar based sealcoat has been identified as a source of polycyclic aromatic hydrocarbons (PAHs) in the environment. This study measured the long-term release of PAHs in parking lot runoff and found that the presence of coal tar sealant increased the mass of PAHs released in runoff by over an order of magnitude. PAH concentrations in stormwater from two coal tar sealed parking lots and one unsealed parking lot (control) were monitored over a two-year period. The measured flow volume and concentrations were used to calculate a mass of 9.8-10.8 kg total Σ16 PAHs per hectare exported in stormwater runoff from the two sealed parking lots and 0.34 kg total Σ16 PAHs per hectare from the unsealed control. The study also measured sediment PAH concentration changes in a receiving drainage and found that even partial coverage of a drainage area by coal tar sealant resulted in measurable increases in PAH sediment concentrations; PAH concentrations in sediment in a stormwater swale receiving runoff from both sealed and unsealed lots increased near the outfall from less than 4 mg/kg prior to sealing to 95.7 mg/kg after sealing. Compound ratio plots and principal components analysis were examined and were able to clearly differentiate between pre- and postsealant samples.

  7. Fullerenes, fulleranes and polycyclic aromatic hydrocarbons in the Allende meteorite

    NASA Technical Reports Server (NTRS)

    Becker, L.; Bunch, T. E.

    1997-01-01

    In this paper, we confirm our earlier observations of fullerenes (C60 and C70) in the Allende meteorite (Becker et al., 1994a, 1995). Fullerene C60 was also detected in two separate C-rich (approximately 0.5-1.0%) dark inclusions (Heymann et al., 1987) that were hand picked from the Allende sample. The amounts of C60 detected were approximately 5 and approximately 10 ppb, respectively, which is considerably less than what was detected in the Allende 15/21 sample (approximately 100 ppb; Becker et al., 1994a, 1995). This suggests that fullerenes are heterogeneously distributed in the meteorite. In addition, we present evidence for fulleranes, (C60Hx), detected in separate samples by laser desorption (reflectron) time-of-flight (TOF) mass spectrometry (LDMS). The LDMS spectra for the Allende extracts were remarkably similar to the spectra generated for the synthetic fullerane mixtures. Several fullerane products were synthesized using a Rh catalyst (Becker et al., 1993a) and separated using high-performance liquid chromatography (HPLC). Polycyclic aromatic hydrocarbons (PAHs) were also observed ppm levels) that included benzofluoranthene and corannulene, a cup-shaped molecule that has been proposed as a precursor molecule to the formation of fullerenes in the gas phase (Pope et al., 1993).

  8. Identifying risk sources of air contamination by polycyclic aromatic hydrocarbons.

    PubMed

    Huzlik, Jiri; Bozek, Frantisek; Pawelczyk, Adam; Licbinsky, Roman; Naplavova, Magdalena; Pondelicek, Michael

    2017-09-01

    This article is directed to determining concentrations of polycyclic aromatic hydrocarbons (PAHs), which are sorbed to solid particles in the air. Pollution sources were identified on the basis of the ratio of benzo[ghi]perylene (BghiPe) to benzo[a]pyrene (BaP). Because various important information is lost by determining the simple ratio of concentrations, least squares linear regression (classic ordinary least squares regression), reduced major axis, orthogonal regression, and Kendall-Theil robust diagnostics were utilized for identification. Statistical evaluation using all aforementioned methods demonstrated different ratios of the monitored PAHs in the intervals examined during warmer and colder periods. Analogous outputs were provided by comparing gradients of the emission factors acquired from the measured concentrations of BghiPe and BaP in motor vehicle exhaust gases. Based on these outputs, it was possible plausibly to state that the influence of burning organic fuels in heating stoves is prevalent in colder periods whereas in warmer periods transport was the exclusive source because other sources of PAH emissions were not found in the examined locations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Polycyclic aromatic hydrocarbon ions and the diffuse interstellar bands

    NASA Technical Reports Server (NTRS)

    Salama, F.; Allamandola, L. J.

    1995-01-01

    Neutral naphthalene (C10H8), phenanthrene (C14H10), and pyrene (C16H10) absorb strongly in the ultraviolet and may contribute to the extinction curve. High abundances are required to produce detectable structures. The cations of these Polycyclic Aromatic Hydrocarbons (PAHs) absorb in the visible. C10H8(+) has 12 discrete absorption bands which fall between 6800 and 5000 A. The strongest band at 6741 A falls close to the weak 6742 A diffuse interstellar band (DIB). Five other weaker bands also match DIBs. The possibility that C10H8(+) is responsible for some of the DIBs can be tested by searching for new DIBS at 6520, 6151, and 5965 A, other moderately strong naphthalene cation band positions. If C10H8(+) is indeed responsible for the 6742 A feature, it accounts for 0.3% of the cosmic carbon. The spectrum of C16H10(+) is dominated by a strong band at 4435 A in an Ar matrix and 4395 A in a Ne matrix, a position which falls very close to the strongest DIB, that at 4430 A. If C16H10(+), or a closely related pyrene-like ion is indeed responsible for the 4430 A feature, it accounts for 0.2% of the cosmic carbon. We also report an intense, very broad UV-to-visible continuum which is associated with both ions and could explain how PAHs convert interstellar UV and visible radiation into IR.

  10. Measurement of polycyclic aromatic hydrocarbon (PAHs) in interplanetary dust particles

    NASA Technical Reports Server (NTRS)

    Clemett, S. J.; Maechling, C. R.; Zare, R. N.; Swan, P. D.; Walker, R. M.

    1993-01-01

    We report here the first definitive measurements of specific organic molecules (polycyclic aromatic hydrocarbons (PAH's)) in interplanetary dust particles (IDP's). An improved version of the microbeam-two-step laser mass spectrometer was used for the analysis. Two IDP's gave similar mass spectra showing an abundance of PAH's. Control samples, including particles of probable terrestrial origin from the same stratospheric collector, gave either null results or quite different spectra. We conclude that the PAH's are probably indigenous to the IDP's and are not terrestrial contaminants. The instrument used to study the particles is a two-step laser mass spectrometer. Constituent neutral molecules of the sample are first desorbed with a pulsed infrared laser beam focussed to 40 micrometers. In the second step, PAH's in the desorbed plume are preferentially ionized by a pulsed UV laser beam. Resulting ions produced by resonant absorption are extracted into a reflectron time-of-flight mass spectrometer. This instrument has high spatial resolution, high ion transmission, unlimited mass range, and multichannel detection of all ion masses from a single laser shot.

  11. Polycyclic aromatic hydrocarbons (PAHs) removal by sorption: A review.

    PubMed

    Lamichhane, Shanti; Bal Krishna, K C; Sarukkalige, Ranjan

    2016-04-01

    Polycyclic aromatic hydrocarbons (PAHs) are organic micro pollutants which are persistent compounds in the environment due to their hydrophobic nature. Concerns over their adverse effects in human health and environment have resulted in extensive studies on various types of PAHs removal methods. Sorption is one of the widely used methods as PAHs possess a great sorptive ability into the solid media and their low aqueous solubility property. Several adsorbent media such as activated carbon, biochar, modified clay minerals have been largely used to remove PAHs from aqueous solution and to immobilise PAHs in the contaminated soils. According to the past studies, very high removal efficiency could be achieved using the adsorbents such as removal efficiency of activated carbon, biochar and modified clay mineral were 100%, 98.6% and >99%, respectively. PAHs removal efficiency or adsorption/absorption capacity largely depends on several parameters such as particle size of the adsorbent, pH, temperature, solubility, salinity including the production process of adsorbents. Although many studies have been carried out to remove PAHs using the sorption process, the findings have not been consolidated which potentially hinder to get the correct information for future study and to design the sorption method to remove PAHs. Therefore, this paper summarized the adsorbent media which have been used to remove PAHs especially from aqueous solutions including the factor affecting the sorption process reported in 142 literature published between 1934 and 2015.

  12. Association of polycyclic aromatic hydrocarbons in housewives' hair with hypertension.

    PubMed

    Wang, Bin; Li, Zhiwen; Ma, Yiqiu; Qiu, Xinghua; Ren, Aiguo

    2016-06-01

    The relationship between polycyclic aromatic hydrocarbons (PAHs) and hypertension remains a subject of debate. The aims of this study were to determine an association of concentrations of PAHs in housewives' hair with hypertension risk and the modification effect of single nucleotide polymorphisms (SNPs) related to Phase I metabolism of PAHs. We recruited 405 women for a cross-sectional study in Shanxi Province, China, including 170 with hypertension (the case group) and 235 without hypertension (the control group). We analyzed 26 individual PAHs in hair samples and the SNPs of the genes including cytochrome P450, family 1, subfamily A, polypeptide 1 (CYP1A1), CYP1A2, CYP1B1 and CYP2E1. Our results showed that seven PAHs in hair samples were measured with detection rate >70%. Only acenaphthylene was found to be associated with an increased risk of hypertension with adjustment for the potential confounders following Bonferroni correction, whereas others not. No SNPs of the concerned genes were found to be associated with the risk of hypertension. A multiple interaction effect of PAHs in housewives' hair and SNPs on hypertension risk was not observed. It was concluded that PAHs tended to contribute to the formation of hypertension.

  13. Measurement of polycyclic aromatic hydrocarbon (PAHs) in interplanetary dust particles

    NASA Technical Reports Server (NTRS)

    Clemett, S. J.; Maechling, C. R.; Zare, R. N.; Swan, P. D.; Walker, R. M.

    1993-01-01

    We report here the first definitive measurements of specific organic molecules (polycyclic aromatic hydrocarbons (PAH's)) in interplanetary dust particles (IDP's). An improved version of the microbeam-two-step laser mass spectrometer was used for the analysis. Two IDP's gave similar mass spectra showing an abundance of PAH's. Control samples, including particles of probable terrestrial origin from the same stratospheric collector, gave either null results or quite different spectra. We conclude that the PAH's are probably indigenous to the IDP's and are not terrestrial contaminants. The instrument used to study the particles is a two-step laser mass spectrometer. Constituent neutral molecules of the sample are first desorbed with a pulsed infrared laser beam focussed to 40 micrometers. In the second step, PAH's in the desorbed plume are preferentially ionized by a pulsed UV laser beam. Resulting ions produced by resonant absorption are extracted into a reflectron time-of-flight mass spectrometer. This instrument has high spatial resolution, high ion transmission, unlimited mass range, and multichannel detection of all ion masses from a single laser shot.

  14. Enhancement of polycyclic aromatic hydrocarbon biodegradation in the rhizosphere

    SciTech Connect

    Kim, S.C.; Banks, M.K.; Schwab, A.P.

    1994-12-31

    Polycyclic aromatic hydrocarbons (PAHs) are a class of potentially hazardous chemicals that exhibit toxic, mutagenic or carcinogenic properties. Microbial degradation is the major route through which PAHs are removed from contaminated environments although other mechanisms such as volatilization, leaching and photodegradation may also be effective. The rhizosphere contains a diversity of microorganisms that contribute to plant health and soil homeostasis. Recent studies indicate that microorganisms in the rhizosphere can degrade toxicants of concern to human health and the environment. The increased density and diversity of rhizosphere microflora may be an important factor for enhanced microbial degradation of PAHs. The objective of this study is to evaluate degradation of a number of different PAHs in rhizosphere and non-rhizosphere soil. It has been shown that the biodegradation rates of PAHs increase as the number of PAH rings decrease, but there is little information about the biodegradation in rhizosphere soil. The study will provide results from a microcosm experiment designed to evaluate degradation of PAHs in rhizosphere and non-rhizosphere. Also, kinetic models will be developed to represent data collected.

  15. Diversity of metabolic capacities among strains degrading polycyclic aromatic hydrocarbons

    SciTech Connect

    Bouchez, M.; Besnaienou, B.; Blanchet, D.; Vandecasteele, J.P.

    1995-12-31

    Strains of Pseudomonas and Rhodococcus genera were isolated for their capacity to use, as a sole carbon and energy source, one of the following polycyclic aromatic hydrocarbons (PAHs): naphthalene (NAP), fluorene (FLU), phenanthrene (PHE), anthracene (ANT), fluoranthene (FLT), and pyrene (PYR). The range of PAHs supporting growth of these pure strains was usually restricted, but several other hydrocarbons were used by Rhodococcus sp. All strains could grow on simple organic acids. Maximal specific growth rates ({mu}{sub max}) of all strains on their PAH growth substrates were determined by respirometry. No clear relationships between {mu}{sub max} values and the molecular weight or water solubility of PAHs were apparent, but Pseudomonas sp. exhibited the highest {mu}{sub max} values. Carbon balances for PAH biodegradation were established. Differences between strains were observed, but high mineralization rates and low production of soluble metabolites were obtained for all PAHs. Bacterial biomass represented 16% to 35% of the carbon consumed. Strain diversity was also apparent in the interactions observed in the degradation of a mixture of two PAHs by individual strains, which often involved inhibition of PAH substrate degradation, with or without cometabolization of the second PAH.

  16. Biodegradation of polycyclic aromatic hydrocarbons in rhizosphere soil

    SciTech Connect

    Schwab, A.P.; Banks, M.K.; Arunachalam, M.

    1995-12-31

    Increased contaminant biodegradation in soil in the presence of plants has been demonstrated for several classes of organic compounds. Although enhanced dissipation of polycyclic aromatic hydrocarbons (PAHs) was observed previously in the rhizosphere of several plant species, the mechanism of this effect has not been assessed. A laboratory experiment was conducted to test the importance of cometabolism and the presence of common rhizosphere organic acids on the loss of PAHs (pyrene and phenanthrene) from soil. The role of cometabolism in the mineralization of pyrene was tested by observing the impact of adding phenanthrene to soil containing {sup 14}C-pyrene and observing the effects on {sup 14}CO{sub 2} generation. Adding phenanthrene apparently induced cometabolism of pyrene, particularly in the presence of organic acids. In a subsequent experiment, mineralization of pyrene to {sup 14}CO{sub 2} was significantly greater in soil from the rhizospheres of warm-season grasses, sorghum (Sorghum bicolor L.) and bermuda grass (Cynodon dactylon L.), compared to soil from alfalfa (Medicago sativa L.), which did not differ from sterilized control soil. A highly branched, fine root system appears to be more effective in enhancing biodegradation than taproots, and the presence of organic acids increases rates of PAH mineralization.

  17. Polycyclic aromatic hydrocarbon biodegradation by a mixed bacterial culture

    SciTech Connect

    Dreyer, G.; Koenig, J.; Ringpfeil, M.

    1995-12-31

    Biodegradation of polycyclic aromatic hydrocarbons (PAHs), which are a complex mixture of organic compounds, was demonstrated using a bacterial mixed culture selected from a contaminated site by the BIOPRACT GmbH. The investigations were carried out in a laboratory fermenter using emulsified tar oil as the substrate to determine the following: (1) concentration of the single PAH and of the sum of PAHs relative to fermentation time, (2) carbon dioxide (CO{sub 2}) and oxygen (O{sub 2}) content in the outflowing air during fermentation, (3) chemical oxygen demand (COD) of the broth, and (4) toxicity of the broth before and after fermentation according to the bioluminescence test (DIN 38412, part 34/1). The results of this model experiment indicated that the investigated mixed culture is able to effectively metabolize the PAHs contained in tar oil, including the higher condensed compounds such as benzo(a)pyrene. In the first 8 days of fermentation, the PAH sum decreased to below 5% of the starting concentration connected with a five-fold reduction of the toxic effect on Vibrio fischeri. The PAH degradation rate correlated with the rate of COD decrease, the rate of evolving CO{sub 2}, and the consumption of O{sub 2}.

  18. Methanogenic biodegradation of two-ringed polycyclic aromatic hydrocarbons.

    PubMed

    Berdugo-Clavijo, Carolina; Dong, Xiaoli; Soh, Jung; Sensen, Christoph W; Gieg, Lisa M

    2012-07-01

    Polycyclic aromatic hydrocarbons (PAH) are widespread in methane-rich subsurface environments, such as oil reservoirs and fuel-contaminated aquifers; however, little is known about the biodegradation of these compounds under methanogenic conditions. To assess the metabolism of PAH in the absence of electron acceptors, a crude oil-degrading methanogenic enrichment culture was tested for the ability to biodegrade naphthalene, 1-methylnaphthalene (1-MN), 2-methylnaphthalene (2-MN), and 2, 6-dimethylnaphthalene (2, 6-diMN). When methane was measured as an indicator of metabolism, nearly 400 μmol of methane was produced in the 2-MN- and 2, 6-diMN-amended cultures relative to substrate-unamended controls, which is close to the amount of methane stoichiometrically predicted based on the amount of substrate added (51-56 μmol). In contrast, no substantial methane was produced in the naphthalene- and 1-MN-amended enrichments. In time course experiments, metabolite analysis of enrichments containing 2-MN and 2, 6-diMN revealed the formation of 2-naphthoic acid and 6-methyl-2-naphthoic acid, respectively. Microbial community analysis by 454 pyrosequencing revealed that these PAH-utilizing enrichments were dominated by archaeal members most closely affiliated with Methanosaeta and Methanoculleus species and bacterial members most closely related to the Clostridiaceae, suggesting that these organisms play an important role in the methanogenic metabolism of the substituted naphthalenes in these cultures.

  19. Magnetic Beads-based Bioelectrochemical Immunoassay of Polycyclic Aromatic Hydrocarbons

    SciTech Connect

    Lin, Ying-Ying; Liu, Guodong; Wai, Chien M.; Lin, Yuehe

    2007-07-01

    A simple, rapid, and sensitive bioelectrochemical immunoassay method based on magnetic beads (MBs) has been developed to detect polycyclic aromatic hydrocarbons (PAHs). The principle of this bioassay is based on a direct competitive enzyme-linked immunosorbent assay using PAH-antibody-coated MBs and horseradish peroxidase (HRP)-labeled PAH (HRP-PAH). A magnetic process platform was used to mix and shake the samples during the immunoreactions and to separate free and unbound reagents after the liquid-phase competitive immunoreaction among PAH-antibody-coated MBs, PAH analyte, and HRP-PAH. After a complete immunoassay, the HRP tracers attached to MBs were transferred to a substrate solution containing 3, 3´, 5, 5´- tetramethylbenzidine (TMB) and hydrogen peroxide (H2O2) for electrochemical detection. The voltammetric characteristics of the substrate were investigated, and the reduction peak current of TMB was used to quantify the concentration of PAH. The different parameters, including the amount of HRP-PAH conjugates, the enzyme catalytic reaction time, and the pH of the supporting electrolyte that governs the analytical performance of the immunoassay have been studied in detail and optimized. The detection limit of 50 pg mL-1 was obtained under optimum experimental conditions. The performance of this bioelectrochemical magnetic immunoassay was successfully evaluated with tap water spiked with PAHs, indicating that this convenient and sensitive technique offers great promise for decentralized environmental applications.

  20. Reptilian exposure to polycyclic aromatic hydrocarbons and associated effects.

    PubMed

    Zychowski, Gregory V; Godard-Codding, Céline A J

    2017-01-01

    Reptiles are an underrepresented taxon in ecotoxicological literature, and the means by which toxicants play a role in population declines are only partially understood. Among the contaminants of interest for reptiles are polycyclic aromatic hydrocarbons (PAHs), a class of organic compounds that is already a concern for numerous other taxa. The objectives of the present review are to summarize the existing literature on reptilian exposure to PAHs and synthesize general conclusions, to identify knowledge gaps within this niche of research, and to suggest future directions for research. Results confirm a relative scarcity of information on reptilian exposure to PAHs, although research continues to grow, particularly after significant contamination events. The orders Testudines and Squamata are better represented than the orders Crocodilia and Rhynchocephalia. For the taxonomic orders with relevant literature (all but Rhynchocephalia), some species are more frequently represented than others. Few studies establish solid cause-effect relationships after reptilian exposure to PAHs, and many more studies are suggestive of effect or increased risk of effect. Despite the scarcity of information in this area, researchers have already employed a wide variety of approaches to address PAH-related questions for reptiles, including molecular techniques, modeling, and field surveys. As more research is completed, a thoughtful interpretation of available and emerging data is necessary to make the most effective use of this information. Environ Toxicol Chem 2017;36:25-35. © 2016 SETAC. © 2016 SETAC.

  1. Distribution of polycyclic aromatic hydrocarbons in lime spray dryer ash

    SciTech Connect

    Ping Sun; Panuwat Taerakul; Linda K. Weavers; Harold W. Walker

    2005-10-01

    Four lime spray dryer (LSD) ash samples were collected from a spreader stoker boiler and measured for their concentrations of 16 U.S. EPA specified polycyclic aromatic hydrocarbons (PAHs). Results showed that the total measured PAH concentration correlated with the organic carbon content of the LSD ash. Each LSD ash sample was then separated using a 140 mesh sieve into two fractions: a carbon-enriched fraction ({gt}140 mesh) and a lime-enriched fraction ({lt}140 mesh). Unburned carbon was further separated from the carbon-enriched fraction with a lithiumheteropolytungstate (LST) solution. PAH measurements on these different fractions showed that unburned carbon had the highest PAH concentrations followed by the carbon-enriched fraction, indicating that PAHs were primarily associated with the carbonaceous material in LSD ash. However, detectable levels of PAHs were also found in the lime-enriched fraction, suggesting that the fine spray of slaked lime may sorb PAH compounds from the flue gas in the LSD process. 37 refs., 5 figs., 4 tabs.

  2. Doped polycyclic aromatic hydrocarbons as building blocks for nanoelectronics: a theoretical study.

    PubMed

    Dral, Pavlo O; Kivala, Milan; Clark, Timothy

    2013-03-01

    Density functional theory (DFT) and semiempirical UHF natural orbital configuration interaction (UNO-CI) calculations are used to investigate the effect of heteroatom substitution at the central position of a model polycyclic aromatic hydrocarbon. The effects of the substitution on structure, strain, electronic and spectral properties, and aromaticity of the compounds are discussed.

  3. Scavenging ratio of polycyclic aromatic compounds in rain and snow at the Athabasca oil sands region

    NASA Astrophysics Data System (ADS)

    Zhang, L.; Cheng, I.; Muir, D.; Charland, J.-P.

    2014-07-01

    Athabasca oil sands industry in northern Alberta, Canada is a possible source of polycyclic aromatic compounds (PACs). Monitored PACs, including polycyclic aromatic hydrocarbons (PAHs), alkylated PAHs, and dibenzothiophenes, in precipitation and in air at three near-source sites in the Fort MacKay and Fort McMurray area during May 2011 to August 2012 were analyzed to generate a database of scavenging (or washout) ratios (Wt) for PACs scavenged by both snow and rain. Median precipitation and air concentrations of parent PAHs over the May 2011 to August 2012 period ranged from 0.3-184.9 (chrysene) ng L-1 and 0.01-3.9 (naphthalene) ng m-3, respectively, which were comparable to literature values. Higher concentrations in precipitation and air were observed for alkylated PAHs and dibenzothiophenes. The median precipitation and air concentrations were 11.3-646.7 (C3-fluoranthene/pyrene) ng L-1 and 0.21-16.9 (C3-naphthalene) ng m-3, respectively, for alkylated PAHs, and 8.5-530.5 (C4-dibenzothiophene) ng L-1 and 0.13-6.6 (C2-dibenzothiophene) ng m-3 for dibenzothiophenes and their alkylated derivatives. Median Wt over the measurement period were 6100-1.1 × 106 from snow scavenging and 350-2.3 × 105 from rain scavenging depending on the PAC species. Median Wt for parent PAHs were within the range of those observed at other urban and suburban locations. But Wt for acenaphthylene in snow samples was 2-7 times higher. Some individual snow and rain samples exceeded literature values by a factor of 10. Wt for benzo(a)pyrene, dibenz(a,h)anthracene, and benzo(g,h,i)perylene in snow samples had reached 107, which is the maximum for PAH snow scavenging ratios reported in literature. From the analysis of data subsets, Wt for particulate-phase dominant PACs were 14-20 times greater than gas-phase dominant PACs in snow samples and 7-20 times greater than gas-phase dominant PACs in rain samples. Wt from snow scavenging was ∼9 times greater than rain scavenging for particulate

  4. Inhibitory effects of polycyclic aromatic hydrocarbons (PAHs) on photosynthetic performance are not related to their aromaticity.

    PubMed

    Jajoo, Anjana; Mekala, Nageswara Rao; Tomar, Rupal Singh; Grieco, Michele; Tikkanen, Mikko; Aro, Eva-Mari

    2014-08-01

    Polycyclic aromatic hydrocarbons (PAHs) are very toxic and highly persistent environmental pollutants which accumulate in soil and affect growth of the plants adversely. This study aims to investigate inhibitory effects of 3 major PAH particularly on photosynthetic processes in Arabidopsis thaliana grown in soil treated with PAH. The 3 PAH chosen differ from each other in aromaticity (number of rings) comprising their structure (2 rings: naphthalene, 3 rings: anthracene and 4 rings: pyrene). Several growth parameters and Chlorophyll a fluorescence was monitored in PAH treated plants. BN-PAGe analysis was done in order to get information about change in the protein conformation. PAH treatment led to increased value of Fo which collaborated with increase in the amount of free LHC as seen through BN-Page analysis. Thus PAH were found to inhibit PS II photochemistry and caused distinct change in pigment composition. However the results led us to infer that 3-ring anthracence is more inhibitory as compared to 2-ring naphthalene and 4-ring pyrene. This indicates that aromaticity of PAH is unrelated to their response on photosynthetic processes.

  5. The Exobiological Role of Interstellar Polycyclic Aromatic Hydrocarbons and Ices

    NASA Technical Reports Server (NTRS)

    Hudgins, Douglas M.; DeVincenzi, Donald (Technical Monitor)

    2002-01-01

    Tremendous strides have been made in our understanding of interstellar material over the past twenty years thanks to significant, parallel developments in observational astronomy and laboratory astrophysics. Before this time, the composition of interstellar dust was largely guessed-at, the presence of ices in interstellar clouds ignored, and the notion that large, gas phase, carbon rich molecules might be abundant and widespread throughout the interstellar medium (ISM) considered impossible. Today, the composition of dust in the ISM is reasonably well constrained to micron-sized cold refractory materials comprised of amorphous and crystalline silicates mixed with an amorphous carbonaceous material containing aromatic structural units and short, branched aliphatic chains. Shrouded within the protective confines of cold, opaque molecular clouds--the birthplace of stars and planets--these cold dust particles secrete mantles of mixed molecular ices whose compositions are also well constrained. Finally, amidst the molecular inventory of these ice mantles are likely to be found polycyclic aromatic hydrocarbons (PAHs), shockingly large molecules by the standards of interstellar chemistry, the telltale infrared spectral signature of which is now recognized throughout the Universe. In the first part of this talk, we will review the spectroscopic evidence that forms the basis for the currently accepted abundance and ubiquity of PANs in the ISM. We will then look at a few specific examples which illustrate how experimental and theoretical data can be applied to interpret the interstellar spectra and track how the PAN population evolves as it passes from its formation site in the circumstellar outflows of dying stars, through the various phases of the ISM, and into forniing planetary systems. Nevertheless, despite the fact that PANs likely represent the single largest molecular reservoir of organic carbon in evolving planetary systems, they are not what would be considered

  6. The Exobiological Role of Interstellar Polycyclic Aromatic Hydrocarbons and Ices

    NASA Technical Reports Server (NTRS)

    Hudgins, Douglas M.; DeVincenzi, Donald (Technical Monitor)

    2002-01-01

    Tremendous strides have been made in our understanding of interstellar material over the past twenty years thanks to significant, parallel developments in observational astronomy and laboratory astrophysics. Before this time, the composition of interstellar dust was largely guessed-at, the presence of ices in interstellar clouds ignored, and the notion that large, gas phase, carbon rich molecules might be abundant and widespread throughout the interstellar medium (ISM) considered impossible. Today, the composition of dust in the ISM is reasonably well constrained to micron-sized cold refractory materials comprised of amorphous and crystalline silicates mixed with an amorphous carbonaceous material containing aromatic structural units and short, branched aliphatic chains. Shrouded within the protective confines of cold, opaque molecular clouds--the birthplace of stars and planets--these cold dust particles secrete mantles of mixed molecular ices whose compositions are also well constrained. Finally, amidst the molecular inventory of these ice mantles are likely to be found polycyclic aromatic hydrocarbons (PAHs), shockingly large molecules by the standards of interstellar chemistry, the telltale infrared spectral signature of which is now recognized throughout the Universe. In the first part of this talk, we will review the spectroscopic evidence that forms the basis for the currently accepted abundance and ubiquity of PANs in the ISM. We will then look at a few specific examples which illustrate how experimental and theoretical data can be applied to interpret the interstellar spectra and track how the PAN population evolves as it passes from its formation site in the circumstellar outflows of dying stars, through the various phases of the ISM, and into forniing planetary systems. Nevertheless, despite the fact that PANs likely represent the single largest molecular reservoir of organic carbon in evolving planetary systems, they are not what would be considered

  7. Asymmetric Intramolecular Alkylation of Chiral Aromatic Imines via Catalytic C-H Bond Activation

    SciTech Connect

    Watzke, Anja; Wilson, Rebecca; O'Malley, Steven; Bergman, Robert; Ellman, Jonathan

    2007-04-16

    The asymmetric intramolecular alkylation of chiral aromatic aldimines, in which differentially substituted alkenes are tethered meta to the imine, was investigated. High enantioselectivities were obtained for imines prepared from aminoindane derivatives, which function as directing groups for the rhodium-catalyzed C-H bond activation. Initial demonstration of catalytic asymmetric intramolecular alkylation also was achieved by employing a sterically hindered achiral imine substrate and catalytic amounts of a chiral amine.

  8. Origin of polycyclic aromatic hydrocarbons in lake sediments of the Mackenzie Delta.

    PubMed

    Headley, John V; Marsh, Philip; Akre, Christine J; Peru, Kerry M; Lesack, Lance

    2002-08-01

    The concentrations and distribution of polycyclic aromatic hydrocarbons (PAHs) were assessed in sediment cores from among 14 lakes from three regions comprising a transect across the central Mackenzie Delta. PAHs were consistently found in the lake sediments, with parent concentrations in the 20-200 ng/g range. Concentrations were generally independent of depth in the sediment cores and this pattern was similar among the 3 regions of the delta. Concentrations increased in a westerly direction among the regions. For some lakes, the concentration of PAHs decreased with decreasing flooding frequency, and decreasing sedimentation rates. For the latter, maximum concentrations occurred at shallower depths within the sediment cores as flooding frequency among the lakes decreased. The distributions of C0-C4 alkylated 2- and 3- ring PAHs were consistent with a petrogenic origin, while the corresponding distribution of 4-ring PAHs appears to be more consistent with a biogenic or pyrogenic origin. Based on relative contributions to the overall PAH budget, a petrogenic source appears to be dominant. However, the pyrene/fluoranthene ratio is more consistent with a source derived from peat. The alkylated PAH profiles are inconsistent with those in the Athabasca River system, and supports a previously published hypothesis that the contribution of PAHs from the Athabasca oil sands to the lower Mackenzie River is minimal. A double ratio plot of chrysene vs dibenzothiophene, diagnostic of weathering, suggests most weathering occurred before the sediments were deposited in the lakes, while a double ratio plot of dibenzothiophene vs phenanthrene suggests a common source of PAHs across the delta, despite differing water sources from east to west across the delta. PAH inputs to the delta appear to mirror sediment inputs documented in previous work, where high sediment input from the Mackenzie mainstem during high floods dominates the delta sediment influx and masks any influence of the

  9. Source- and region-specific distribution of polycyclic aromatic hydrocarbons in sediments from Jinhae Bay, Korea.

    PubMed

    Yim, Un Hyuk; Hong, Sang Hee; Ha, Sung Yong; Han, Gi Myung; An, Joon Geon; Kim, Nam Sook; Lim, Dhong-Il; Choi, Hyun-Woo; Shim, Won Joon

    2014-02-01

    This study surveyed polycyclic aromatic hydrocarbons (PAHs) at 80 sites in sediment from Jinhae Bay, which consists of Masan Bay (MSB), Haengam Bay (HAB), Bay Proper (JBP), Wonmoon Bay (WMB), and Gohyun Bay (GHB). Levels of the EPA 16 priority PAHs, 5 groups of alkylated PAH homologues and 2 biogenic PAHs were determined. Total PAHs (sum of all target PAHs) ranged from 37.0 ng/g to 3,110 ng/g with a mean of 339 ng/g. WMB had the highest concentration (473 ± 665 ng/g: average ± standard deviation) followed by GHB (214 ± 141 ng/g), MSB (175 ± 358 ng/g), JBP (133 ± 86.0 ng/g) and HAB (118 ± 129 ng/g). A tiered-source identification approach using the pyrogenic index, PAH isomer ratios and alkylated PAH double ratios found that both pyrogenic and petrogenic PAHs were dominant, and identified three different source- and region-specific groups. Input pathway tracers, such as butyltins, nonylphenols and dibenzothiophenes, were used to track the main input pathways. A shipyard and urban runoff were identified as the major input pathways of PAHs into GHB, and urban runoff was identified as a major pathway into MSB and WMB. Used crankcase oil, diesel exhaust, tyre debris and asphalt were considered to be the dominant PAH sources in urban runoff. Several PAH compounds exceeded the interim marine sediment quality guidelines for the protection of aquatic environments, among which dibenz[a,h]anthracene exceeded the guidelines in 16% of surveyed sites. Current PAH levels in MSB indicated an improving situation following the implementation of a total pollutant load management system (TPLMS); this is in accordance with other studies. WMB was recognised as an area of concern within this bay, suggesting the update of the TPLMS in this region.

  10. Quantification of Twenty-one Metabolites of Methylnaphthalenes and Polycyclic Aromatic Hydrocarbons in Human Urine

    PubMed Central

    Li, Zheng; Romanoff, Lovisa C.; Trinidad, Debra A.; Pittman, Erin N.; Hilton, Donald; Hubbard, Kendra; Carmichael, Hasan; Parker, Jonathan; Calafat, Antonia M.; Sjödin, Andreas

    2015-01-01

    Polycyclic aromatic hydrocarbons (PAHs) and their alkylated derivatives, such as methylnaphthalenes (MeNs), are harmful pollutants ubiquitously present in the environment. Exposure to PAHs has been linked to a variety of adverse health effects and outcomes, including cancer. Alkyl PAHs have been proposed as petrogenic source indicators because of their relatively high abundance in unburned petroleum products. We report a method to quantify 11 urinary methyl naphthols (Me-OHNs), metabolites of 1- and 2-methylnaphthalenes, and 10 monohydroxy PAH metabolites (OH-PAHs), using automated liquid-liquid extraction and isotope dilution gas chromatography tandem mass spectrometry (GC-MS/MS). After spiking urine (1 mL) with 13C-labeled internal standards, the conjugated target analytes were hydrolyzed enzymatically in the presence of ascorbic acid. Then, their free species were preconcentrated into 20% toluene in pentane, derivatized and quantified by GC-MS/MS. The 11 Me-OHNs eluted as 6 distinct chromatographic peaks, each representing 1–3 isomers. Method detection limits were 1.0–41 pg/mL and the coefficients of variance in quality control materials were 4.7–19%. The method was used to analyze two National Institute of Standards and Technology’s Standard Reference Materials and samples from 30 smokers and 30 non-smokers. Geometric mean concentrations were on average 37 (Me-OHNs) and 9.0 (OH-PAHs) fold higher in smokers than in non-smokers. These findings support the usefulness of Me-OHNs as potential biomarkers of non-occupational exposure to MeNs and sources containing MeNs. PMID:24714969

  11. Historical record and sources of polycyclic aromatic hydrocarbons in core sediments from the Yangtze Estuary, China.

    PubMed

    Liu, M; Baugh, P J; Hutchinson, S M; Yu, L; Xu, S

    2000-11-01

    Polycyclic aromatic hydrocarbons (PAHs) in a sediment core taken from intertidal flat in the Yangtze Estuary were determined by gas chromatography-mass spectrometry. The results indicate that the total concentration of PAHs ranged from 0.08 to 11.74 microg/g. The concentration levels of total and individual PAHs changed dramatically with depth. The concentrations of PAHs were relatively high above 35 cm depth and remained constantly low below this depth. The historical record of PAHs in the core shows subsurface maximum (one or more peak values), followed by decreased levels to the surface and with depth. And, PAH sediment record in the core profile is in agreement with historically sewage discharge events during the 1980s to 1990s. The distribution of target molecule acenephthene, the fluoranthene/pyrene ratio, the proportion of 2-3-ring and 4-5-ring PAHs, and alkylated naphthalene to parent naphthalene in the core profile show that the sources in this area are characterized by petroleum-derived PAH contamination (mainly sewage discharge and the river runoff) and the incorporation of atmospheric inputs. Studies indicate the PAH profile pattern in this site in comparison with other regions appear to reflect its particular local position (near the sewage outlet). Moreover, physico-chemical conditions and sedimentation rate as well as biodegradation also affect the PAH concentration levels in the core sediments.

  12. Impact of vegetation on sedimentary organic matter composition and polycyclic aromatic hydrocarbon attenuation.

    PubMed

    Gregory, Samuel T; Shea, Damian; Guthrie-Nichols, Elizabeth

    2005-07-15

    Results from natural and engineered phytoremediation systems provide strong evidencethatvegetated soils mitigate polycyclic aromatic hydrocarbon (PAH) contamination. However, the mechanisms by which PAH mitigation occurs and the impact of plant organic matter on PAH attenuation remain unclear. This study assessed the impact of plant organic matter on PAH attenuation in labile and refractory sediments fractions from a petroleum distillate waste pit that has naturally revegetated. Samples were collected in distinct zones of barren and vegetated areas to assess changes to organic matter composition and PAH content as vegetation colonized and became established in the waste pit. Sediments were fractionated into bulk sediment and humin fractions and analyzed for organic matter composition by isotope ratio mass spectrometry (delta (13)C), 13C nuclear magnetic resonance (13C NMR), delta 14C AMS (accelerator mass spectrometry), and percent organic carbon (%TOC). Gas chromatography mass spectrometry (GC/ MS) of lipid extracts of SOM fractions provided data for PAH distribution histograms, compound weathering ratios, and alkylated and nonalkylated PAH concentrations. Inputs of biogenic plant carbon, PAH weathering, and declines in PAH concentrations are most evidentfor vegetated SOM fractions, particularly humin fractions. Sequestered PAH metabolites were also observed in vegetated humin. These results show that plant organic matter does impact PAH attenuation in both labile and refractory fractions of petroleum distillate waste.

  13. Distribution and sources of polycyclic aromatic hydrocarbon (PAH) in marine environment of China

    NASA Astrophysics Data System (ADS)

    Zheng, Jinshu; Richardson, Bruce J.; Shouming, O.; Zheng, Jianhua

    2004-06-01

    Polycyclic aromatic hydrocarbons (PAHs) are potentially carcinogenic and mutagenic compounds that have raised considerable environmental concern. The highest concentrations of PAHs in the coastal sediment samples in China was 5.8 11.0μg/g (dry weight) in the core from the Huangpu River, Shanghai. The second highest concentration of PAHs was 4.42μg/g (dry weight) in surface sediment of Victoria Harbour in Hong Kong, and 5.73μg/g (dry weight) in sediment of Jiaozhou Bay, Qingdao City. The low concentrations of PAHs were always in the sediments far away from industrial zones and cities, and ranged from 0.10 to 0.30μg/g (dry weight). Several environmental parameters are considered for the identification of sources of PAHs in marine environment. High proportion of naphthalene, low molecular weight PAHs and alkylated PAHs, plus high ratio of phenanthrene to anthracene (>15) and low ratio of fluoranthene to pyrene (<1) suggested a petrogenic source. According to these parameters, the Changjiang (Yangtze) River estuary of Shanghai, Jiaozhou Bay of Qingdao City, Zhujiang (Pearl) River mouth, Jiulong River mouth and most of Hong Kong coastal waters were heavily contaminated by PAHs from petrogenic sources. However, PAHs in rural coastal areas were dominated by pyrolytic origin PAHs. This review clearly showed that oil pollution and incomplete combustion of oil, coal and biomass are the main reason for PAHs anormalies in the study areas.

  14. Biomonitoring potentials of polycyclic aromatic hydrocarbons (PAHs) by higher plants from an oil exploration site, Nigeria.

    PubMed

    Sojinu, O Samuel; Sonibare, Oluwadayo O; Ekundayo, O; Zeng, Eddy Y

    2010-12-15

    Higher plants sampled from a moderately polluted exploration site were analyzed with gas chromatography-mass spectrometry to determine the occurrence and sources of polycyclic aromatic hydrocarbons (PAHs). The concentrations of the sum of 28 target PAHs (designated as Σ(28)PAH) in the leaves of higher plant samples ranged from 365 to 2870 μg/kg with an average of 1430 μg/kg. The majority of the target compounds were detected except 9,10-diphenyl anthracene and dibenzo(a,h)anthracene, which were below the detection limits in most plant samples. In addition, the concentrations of the 2- and 3-ring PAHs, especially naphthalene and its alkylated derivatives, were generally higher than the 4-, 5- and 6-ring PAHs. Based on the results obtained in the present study, higher plants, especially non-woody annual and perennial plants could serve as good phytoremediators for a PAHs polluted sites. Copyright © 2010 Elsevier B.V. All rights reserved.

  15. Effects of oil pipeline explosion on ambient particulate matter and their associated polycyclic aromatic hydrocarbons.

    PubMed

    Zhao, Yue; Cao, Lixin; Zhou, Qing; Que, Qiming

    2015-01-01

    Effects of the oil pipeline explosion on PM(2.5)-associated polycyclic aromatic hydrocarbons (PAHs) and their substituted (alkylated, nitrated, oxygenated, hydroxyl and chlorinated) derivatives are assessed near the accident scene of Qingdao, China. Compared with those in TSP-PM(2.5), gaseous phase, burn residue and unburned crude oil, eighty-nine PAHs in PM(2.5) are identified and quantified to investigate the composition, temporal and spatial distribution, and sources. The concentrations of PM(2.5)-associated parent PAHs increase approximately seven times from the non-explosion samples to the explosion samples (mean ± standard deviation: 112 ± 2 vs 764 ± 15 ng/m(3)), while some substituted products (nitro- and oxy-) increase by two orders of magnitude (3117 ± 156 pg/m(3) vs 740 ± 37 ng/m(3)). The toxicity evaluation indicates the BaP equivalent concentrations (based on the US EPA's toxicity factors) in PM(2.5) are much higher than those in the other phases, especially for a long duration after the tragic accident.

  16. Polycyclic aromatic hydrocarbons (PAHs) in starfish body and bottom sediments in Mohang Harbor (Taean), South Korea.

    PubMed

    Kim, Chang Joon; Hong, Gi Hoon; Kim, Hye Eun; Yang, Dong Beom

    2014-07-01

    The concentrations of 27 polycyclic aromatic hydrocarbons (PAHs) were determined in bottom sediments and starfish from Mohang Harbor (MH) in Taean peninsula, South Korea. In December 2007, crude oil washed ashore from the M/V Hebei Spirit and was subsequently cleaned up within a few months of the incident. The ecological risk, bioaccumulation factor (BAF), and composition of the 27 PAHs were examined. The PAH concentrations in the bottom sediment ranged from 24 to 366 μg/kg dried weight, and the ecological risk was determined as minimal (mERL-Q < 1). Total PAH concentrations in Asterina pectinifera (inside seawall) and Asterias amurensis (outside seawall) were 1,226 and 1,477 μg/kg dry weight (d.w.), respectively. The total BAFs (∑BAF) for A. amurensis was 3.8 times higher than that of A. pectinifera, and the PAH concentrations of 5-6 log K OW were highest in the two starfish species. Further, PAH fingerprint analysis (nine alkyl-substituted PAHs fraction, low molecular weight (LMW)/high molecular weight (HMW), Phe/Ant, and Flu/Pyr), and principal component analysis (PCA) based on three crude oil samples from the M/V Hebei Spirit showed no remaining influence of crude oil.

  17. Effect of interface fertilization on biodegradation of polycyclic aromatic hydrocarbons present in nonaqueous-phase liquids.

    PubMed

    Tejeda-Agredano, M C; Gallego, S; Niqui-Arroyo, J L; Vila, J; Grifoll, M; Ortega-Calvo, J J

    2011-02-01

    The main goal of this study was to use an oleophilic biostimulant (S-200) to target possible nutritional limitations for biodegradation of polycyclic aromatic hydrocarbons (PAHs) at the interface between nonaqueous-phase liquids (NAPLs) and the water phase. Biodegradation of PAHs present in fuel-containing NAPLs was slow and followed zero-order kinetics, indicating bioavailability restrictions. The biostimulant enhanced the biodegradation, producing logistic (S-shaped) kinetics and 10-fold increases in the rate of mineralization of phenanthrene, fluoranthene, and pyrene. Chemical analysis of residual fuel oil also evidenced an enhanced biodegradation of the alkyl-PAHs and n-alkanes. The enhancement was not the result of an increase in the rate of partitioning of PAHs into the aqueous phase, nor was it caused by the compensation of any nutritional deficiency in the medium. We suggest that biodegradation of PAH by bacteria attached to NAPLs can be limited by nutrient availability due to the simultaneous consumption of NAPL components, but this limitation can be overcome by interface fertilization.

  18. Polycyclic aromatic hydrocarbon contamination in marine sediments near Kitimat, British Columbia

    SciTech Connect

    Simpson, C.D.; Harrington, C.F.; Cullen, W.R.; Bright, D.A.; Reimer, K.J.

    1998-11-01

    Polycyclic aromatic hydrocarbons (PAHs), like many other hydrophobic organic contaminants, are rapidly sorbed to particles and incorporated within sediments in aquatic systems. The PAH composition within the sediments reflects the source(s) from which the PAHs were derived. However, the ``source signature`` may be altered by postdepositional weathering or biodegradation. In the present study, variation in PAH composition was investigated in size-fractionated sediments and depth-fractionated sediments collected from a Canadian fjord contaminated with aluminum smelter derived PAHs. Multivariate analyses of PAH compositional data consistently showed that different sampling sites could be discriminated on the basis of their PAH composition, but smaller versus larger size fractions within a site could not. The composition of unsubstituted and alkyl-substituted PAHs in a sediment core primarily showed changes with depth that were attributable to enhancement of anthropogenic inputs in the upper core segments. No trends with sediment depth, associated with compound-specific weathering or biotransformation, were noted in the composition of anthropogenically generated PAHs. This may indicate a limited chemical and biological availability of the aluminum smelter derived PAHs.

  19. QSARs for photo-induced toxicity of polycyclic aromatic hydrocarbons (PAHs)

    SciTech Connect

    Mekenyan, O.; Call, D.; Ankley, G.; Veith, G.

    1994-12-31

    Photo-induced toxicity of polycyclic aromatic hydrocarbons (PAHs) was found to be a result of competing internal and external factors which interact to produce a complex, multilinear relationship between toxicity and chemical structure. The relationship between molecular electronic structure and photo-dynamic effects was studied in both ground and excited states. A measure of the energy required for an electron to be elevated from the highest occupied molecular orbital (HOMO) to the lowest unoccupied molecular orbital (LUMO), or HOMO-LUMO gap, provided a useful ground state index to explain the persistence, light absorption, and eventual photo-induced toxicity of PAHs to Daphnia magna. The derived QSARs clearly distinguished photo-induced toxicity differences between pairs of structurally similar PAHs, such as phenanthrene and anthracene, benzo[a]anthracene and tetracene, etc. Those PAHs exhibiting photo-induced toxicity were consistently within a specific HOMO-LUMO gap range. The relationship between the excited state electronic parameters and toxicity was also studied. Significant correlations were found with the measured energies of singlet and triplet states from spectroscopic data. An investigation of the effect of substituent additions on photo-induced acute toxicity of parent PAHs revealed that alkyl and hydroxy moieties did not significantly reduce the HOMO-LUMO gap of the parent PAHs. Nitro, alkene and chloro substituents cause gap reductions, whereby certain derivatives of parent chemicals that were close to the ``toxic region`` of the electronic gap could become phototoxic with such additions.

  20. The carriers of the unidentified infrared emission features: Clues from polycyclic aromatic hydrocarbons with aliphatic sidegroups

    NASA Astrophysics Data System (ADS)

    Yang, X. J.; Glaser, R.; Li, Aigen; Zhong, J. X.

    2017-04-01

    The unidentified infrared emission (UIE) features at 3.3, 6.2, 7.7, 8.6, 11.3 and 12.7 μ m are ubiquitously seen in a wide variety of astrophysical regions in the Milky Way and nearby galaxies as well as distant galaxies at redshifts z ≳ 4. The UIE features are characteristic of the stretching and bending vibrations of aromatic hydrocarbon materials. The 3.3 μ m feature which results from the C-H stretching vibration in aromatic species is often accompanied by a weaker feature at 3.4 μ m. The 3.4 μ m feature is often thought to result from the C-H stretch of aliphatic groups attached to the aromatic systems. The ratio of the observed intensity of the 3.3 μ m aromatic C-H feature (I3.3) to that of the 3.4 μ m aliphatic C-H feature (I3.4) allows one to estimate the aliphatic fraction (e.g., NC, aliph/NC, arom, the number of C atoms in aliphatic units to that in aromatic rings) of the carriers of the UIE features, provided that the intrinsic oscillator strengths (per chemical bond) of the 3.3 μ m aromatic C-H stretch (A3.3) and the 3.4 μ m aliphatic C-H stretch (A3.4) are known. In this review we summarize the computational results on A3.3 and A3.4 and their implications for the aromaticity and aliphaticity of the UIE carriers. We use density functional theory and second-order perturbation theory to derive A3.3 and A3.4 from the infrared vibrational spectra of seven polycyclic aromatic hydrocarbon (PAH) molecules with various aliphatic substituents (e.g., methyl-, dimethyl-, ethyl-, propyl-, butyl-PAHs, and PAHs with unsaturated alkyl chains). The mean band strengths of the aromatic (A3.3) and aliphatic (A3.4) C-H stretches are derived and then employed to estimate the aliphatic fraction of the carriers of the UIE features by comparing the ratio of the intrinsic band strength of the two stretches (A3.4/A3.3) with the ratio of the observed intensities (I3.4/I3.3). We conclude that the UIE emitters are predominantly aromatic, as revealed by the observationally

  1. Infrared Spectroscopy of Matrix-Isolated Polycyclic Aromatic Nitrogen Heterocycles (PANHs)

    NASA Technical Reports Server (NTRS)

    Mattioda, A. L.; Hudgins, D. M.; Bauschlicher, C. W.; Allamandola, L. J.; Biemesderfer, C. D.; Rosi, M.

    2002-01-01

    The mid-infrared spectra of the nitrogen-containing heterocyclic polycyclic aromatic compounds 1-azabenz[a]-anthracene; 2-azabenz[a]anthracene; 1-azachrysene; 2-azachrysene; 4-azachrysene; 2-azapyrene, and 7,8 benzoquinoline in their neutral and cation forms were investigated. The spectra of these species isolated in an argon matrix have been measured. Band frequencies and intensities were tabulated and these data compared with spectra computed using density functional theory at the B3LYP level. The overall agreement between experiment and theory is quite good, in keeping with earlier results on homonuclear polycyclic aromatic hydrocarbons. The differences between the spectral properties of nitrogen bearing aromatics and non-substituted, neutral polycyclic aromatic hydrocarbons will be discussed.

  2. Distribution and Attenuation of Polycyclic Aromatic Hydrocarbons in Gulf of Mexico Seawater from the Deepwater Horizon Oil Accident.

    PubMed

    Boehm, Paul D; Murray, Karen J; Cook, Linda L

    2016-01-19

    The extended duration of the oil release from the Deepwater Horizon accident (April 20-July 15, 2010) triggered a need to characterize environmental exposures in four dimensions through sampling and tracking the changes in distributions, concentrations, and compositions of oil and total polycyclic aromatic hydrocarbons (TPAH) in the Gulf of Mexico over time and space. More than 11,000 water samples were collected offshore during more than 100 cruises and were measured for 50 parent and alkylated polycyclic aromatic hydrocarbons (PAHs). Elevated concentrations (greater than 1 ppb) of TPAH were largely limited to an area within about 20 km of the wellhead in the subsurface deepwaters at 1000-1200 m depth to the southwest of the wellhead and in the top 3 m underlying the surface oil. Concentrations decreased with distance and time, and changes in the PAH composition indicate that these changes were due to differential solubilization, photodegradation, evaporation, and/or biodegradation of individual PAH compounds. These limited areas of elevated PAH concentrations disappeared within weeks after the release was stopped.

  3. Selective Fluorescence Detection of Polycyclic AromaticHydrocarbons in Environmental Tobacco Smoke and Other AirborneParticles

    SciTech Connect

    Mahanama, K.R.R.; Gundel, L.A.; Daisey, J.M.

    1992-11-01

    An analytical method is described for the simultaneous quantitation of polycyclic aromatic hydrocarbons [pAHs] and alkylderivatives [alkyl-PAHs] in 'real world' samples using microbore reversed-phase high performance liquid chromatography in conjunction with two programmable fluorescence detectors. Sensitivity and selectivity were enhanced by analyzing PAHs under their optimum fluorescence wavelengths. The accuracy of the analytical method was evaluated by determination of PAHs in 5 mg of standard reference material SRM 1649. The method was also successfilly employed to analyze major parent PAHs and some alkyl-PAHs from environmental tobacco smoke [ETS] with a sample size of 2 mg using class-selective fluorescence wavelengths. Some alkyl-PAHs were tentatively identified even in the absence of standard compounds. Coeluting pairs were identified and analyzed by careful selection of excitation and emission wavelengths for each compound. Identities of the signals were confirmed by comparing both the retention behavior and the peak-height ratios at two or more different excitation and emission wavelength combinations.

  4. Predicting bioavailability of sediment polycyclic aromatic hydrocarbons to Hyalella azteca using equilibrium partitioning, supercritical fluid extraction, and pore water concentrations.

    PubMed

    Hawthorne, Steven B; Azzolina, Nicholas A; Neuhauser, Edward F; Kreitinger, Joseph P

    2007-09-01

    Polycyclic aromatic hydrocarbon (PAH) bioavailability to Hyalella azteca was determined in 97 sediments from six former manufactured-gas plants and two aluminum smelter sites. Measurements of Soxhlet extractable, rapidly released based on mild supercritical fluid extraction, and pore water dissolved concentrations of 18 parent and 16 groups of alkyl PAHs (PAH34) were used to predict 28 daysurvival based on equilibrium partitioning and hydrocarbon narcosis models. Total PAH concentrations had little relationship to toxicity. Amphipods survived in sediments with PAH34 concentrations as high as 2990 microg/g, while sediments as low as 2.4 microg/g of PAH34 resulted in significant mortality. Equilibrium partitioning using either total extractable or rapidly released concentrations significantly improved predictions. However, pore water PAH34 concentrations were best for predicting amphipod survival and correctly classified toxic and nontoxic sediment samples with an overall model efficiency of 90%. Alkyl PAHs accounted for 80% of the toxicity, demonstrating that careful measurement of the 16 alkyl clusters in pore water is required. Regression analysis of the pore water PAH34 data from 97 field sediments against amphipod survival resulted in a mean 50% lethal residue value of 33 micromol/g of lipid, consistent with 32 micromol/g of lipid for fluoranthene determined by others in controlled laboratory conditions, thus demonstrating the applicability of EPA's hydrocarbon narcosis model when using pore water PAH34 concentrations.

  5. Trace level determination of polycyclic aromatic hydrocarbons in river water with automated pretreatment HPLC.

    PubMed

    Watabe, Yoshiyuki; Kubo, Takuya; Tanigawa, Tetsuya; Hayakawa, Yoshihiro; Otsuka, Koji; Hosoya, Ken

    2013-03-01

    A novel on-line pretreatment pump-injection HPLC system for polycyclic aromatic hydrocarbons is proposed. We report novel pump-injection HPLC-based on-line SPE with a specially designed pretreatment column for the determination of trace amounts of chemical substances in surface water. Polycyclic aromatic hydrocarbons are well known for strong carcinogenicity and thus a severe concentration control is required for drinking water and/or river water, which is the main resource of tap water. We found it possible to detect ng/L levels of polycyclic aromatic hydrocarbons by using pump-injection column switching HPLC with fluorescence detection. To avoid the phenomenon, in which polycyclic aromatic hydrocarbons can be often adsorbed on the surface of flow lines of HPLC by their highly hydrophobicity especially resin-made parts in sample delivery pump, we employed "autodilution" device that provides reliable recovery and repeatability. Additionally, real water samples were collected and then the spiked polycyclic aromatic hydrocarbons were determined at ng/L levels.

  6. Optimization and determination of polycyclic aromatic hydrocarbons in biochar-based fertilizers.

    PubMed

    Chen, Ping; Zhou, Hui; Gan, Jay; Sun, Mingxing; Shang, Guofeng; Liu, Liang; Shen, Guoqing

    2015-03-01

    The agronomic benefit of biochar has attracted widespread attention to biochar-based fertilizers. However, the inevitable presence of polycyclic aromatic hydrocarbons in biochar is a matter of concern because of the health and ecological risks of these compounds. The strong adsorption of polycyclic aromatic hydrocarbons to biochar complicates their analysis and extraction from biochar-based fertilizers. In this study, we optimized and validated a method for determining the 16 priority polycyclic aromatic hydrocarbons in biochar-based fertilizers. Results showed that accelerated solvent extraction exhibited high extraction efficiency. Based on a Box-Behnken design with a triplicate central point, accelerated solvent extraction was used under the following optimal operational conditions: extraction temperature of 78°C, extraction time of 17 min, and two static cycles. The optimized method was validated by assessing the linearity of analysis, limit of detection, limit of quantification, recovery, and application to real samples. The results showed that the 16 polycyclic aromatic hydrocarbons exhibited good linearity, with a correlation coefficient of 0.996. The limits of detection varied between 0.001 (phenanthrene) and 0.021 mg/g (benzo[ghi]perylene), and the limits of quantification varied between 0.004 (phenanthrene) and 0.069 mg/g (benzo[ghi]perylene). The relative recoveries of the 16 polycyclic aromatic hydrocarbons were 70.26-102.99%. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Simulation of polycyclic aromatic hydrocarbons transport in multimedia

    SciTech Connect

    Chen, L.; Chu, C.J.

    1999-07-01

    Many studies have indicated that the threat from toxic air pollutants such as VOCs comes not through inhalation by humans while the pollutants are in a gaseous state but through absorption when the pollutants are in a solid state such as in an aerosol or particulate form. Pollutants such as Polycyclic Aromatic Hydrocarbons (PAHs) usually exist in a semi-volatile state. To assess the risk of the PAHs, one needs to estimate the dose of the pollutants to which a human would be exposed through various pathways. In this study, the authors modified a Spatial Multimedia Compartmental Model (SMCM) originally developed by UCLA Professor Cohen to predict the PAHs distribution among multimedia such as air, water, soil and sediment in the Taipei metropolitan area. Three PAHs were considered in this study. They are Benzo(a)pyrene, Pyrene and Chrysene. When PAHs are emitted into atmosphere, physical and chemical mechanisms may redistribute the PAHs among multimedia. Five cases of PAHs distribution in multimedia were simulated: (1) PAHs distribution in a dry condition, (2) PAHs distribution when there are different dry deposition velocities, (3) PAHs distribution under a single rainfall event, (4) PAHs distribution when there are different soil properties, (5) PAHs distribution under a random rainfall case. The simulation results are concluded: (1) In the dry case, the PAHs accumulate mostly in soil and air compartments, (2) Different dry depositing velocities will affect the PAHs distribution among compartments. (3) Different soil properties affect the PAHs concentration in the soil and sediment compartments, (4) The soil PAHs concentrations usually increase for those PAHs with a high solid/gas ratio. (5) The random rainfall only affects the PAHs concentration in the soil.

  8. Tracing Star Formation Around Quasars With Polycyclic Aromatic Hydrocarbons

    NASA Astrophysics Data System (ADS)

    Bilton, Lawrence Edward

    2016-09-01

    The feedback processes linking quasar activity to galaxy stellar mass growth are not well understood. If star formation is closely causally linked to black hole accretion, one may expect star formation confined to nuclear regions rather than extended over several kpc scales. Since Polycyclic Aromatic Hydrocarbon (PAH) emission features are widely used as tracers of stellar formation, it is, therefore, possible to use PAH emission detected around QSOs to help resolve this question. PAH data from a sample of 63 QSOs procured from the Spitzer Space Telescope’s Infrared Spectrograph (IRS) is used, employing the Spectroscopic Modelling Analysis and Reduction Tool’s (SMART) Advanced Optimal (AdOpt) extraction routines. A composite spectrum was also produced to help determine the average conditions and compositions of star forming regions. It is found, from our high redshift (>1) sample of QSOs, there is a marginally significant extended star formation on average of 34 scales. At low redshift, the median extension after deconvolving the instrumental point spread function is 3.2 , potentially showing evolutionary variations in star formation activity. However, limitations of the spatial resolving power constrain the ability to make any absolute conclusive remarks. It is also found that the QSO/AGN composite has more neutral PAHs than the starbursting and the main sequence galaxies, consistent with the AGN having no contribution to heating the PAH emission, and also consistent with the average PAH emission found on scales (i.e. not confined to the nuclear regions). A tentative detection of water vapour emission from the gravitationally lensed Einstein Cross quasar, QSO J2237+0305, is also presented suggesting a strong molecular outflow possibly driven by the active nucleus.

  9. Photolysis of polycyclic aromatic hydrocarbons adsorbed on fly ash

    SciTech Connect

    Behymer, T.D.

    1987-01-01

    Polycyclic aromatic hydrocarbons (PAH) are formed by the combustion of almost any fuel under oxygen-deficient conditions. Previous laboratory studies have found that many PAH degrade with lifetimes as short as a few hours; however, studies of marine and lacustrine sediments, the ultimate sinks of PAH, have shown relative abundances of PAH which are similar to those in combustion sources; this suggests that PAH are stable in the atmosphere. Eighteen PAH adsorbed on carbon black and fifteen coal fly ashes of varying physical and chemical composition were photolyzed in order to study their atmospheric fate. Photolytic half-lives for these particle-bound PAH were found to be highly dependent on the substrate onto which they were adsorbed. On low-carbon fly ash, PAH showed a wide range of half-lives, indicating a relationship between PAH structure and photochemical reactivity. However, PAH on carbon black and fly ashes with a high-carbon content, show similar half-lives for most PAH including reactive PAH such as anthracene and benzo(a)pyrene. This indicates a photolytic process that is independent of structure and dependent on the physical and chemical nature of the fly ash. Surprisingly, no other parameter accounts for observed PAH reactivity. Substrate characteristics such as surface area, porosity, particle size, surface pH, and iron content have all been suggested to influence the rate of PAH degradation. However, these parameters, measured for substrates studied in this thesis, do not correlate with PAH reactivity. Because carbon black and high-carbon fly ashes stabilize reactive PAH, it is these substrates which would facilitate the transport of PAH from combustion sources through the atmosphere to ultimate sinks.

  10. Efficient polycyclic aromatic hydrocarbons dihydroxylation in direct micellar systems.

    PubMed

    Randazzo, D; Berti, D; Briganti, F; Baglioni, P; Scozzafava, A; Di Gennaro, P; Galli, E; Bestetti, G

    2001-08-05

    Optimization of whole-cell bioconversion of the polycyclic aromatic hydrocarbons (PAHs) anthracene, phenanthrene, and naphthalene to the enantiomerically pure corresponding cis-dihydroxydihydro derivatives by the Escherichia coli JM109 (pPS1778) recombinant strain, carrying the naphthalene dioxygenase and corresponding regulatory genes cloned from Pseudomonas fluorescens N3, in micellar systems, is presented. We show that direct microemulsion systems, where a nonionic surfactant such as 1.5% (v/v) Triton X-100 plus 0.6% to 1.0% (v/v) selected oils are able to solubilize the PAHs tested at relatively high concentrations (initial concentrations in the reaction medium > or =10 mM for naphthalene and phenanthrene and > or =2 mM for anthracene), and allow for more efficient substrate bioconversion. These media, while not affecting bacteria viability and performance, provide increased efficiency and final product yields (100% for naphthalene, >30% for anthracene, >60% for phenanthrene). The phase behavior of the direct microemulsion systems for the different substrates and oils utilized was monitored as a function of their volume fraction by light scattering experiments, and related to the bioconversion results. For anthracene and phenanthrene, the dihydroxylated products have an inhibitory effect on the conversion reactions, thus hindering complete turnover of the substrates. We ascertain that such inhibition is reversible because removal of the products formed allowed the process to start over at rates comparable to initial rates. To allow for complete conversion of the PAHs tested a stepwise or continuous separation of the product formed from the micellar reaction environment is being developed. Copyright 2001 John Wiley & Sons, Inc.

  11. Estimation of Chronic Personal Exposure to Airborne Polycyclic Aromatic Hydrocarbons

    PubMed Central

    Choi, Hyunok; Zdeb, Michael; Perera, Frederica; Spengler, John

    2015-01-01

    Background Polycyclic aromatic hydrocarbons (PAH) exposure from solid fuel burning represents an important public health issue for the majority of the global population. Yet, understanding of individual-level exposures remains limited. Objectives To develop regionally adaptable chronic personal exposure model to pro-carcinogenic PAH (c-PAH) for the population in Kraków, Poland. Methods We checked the assumption of spatial uniformity in eight c-PAH using the coefficients of divergence (COD), a marker of absolute concentration differences. Upon successful validation, we developed personal exposure models for eight pro-carcinogenic PAH by integrating individual-level data with area-level meteorological or pollutant data. We checked the resulting model for accuracy and precision against home outdoor monitoring data. Results During winter, COD of 0.1 for Kraków suggest overall spatial uniformity in the ambient concentration of the eight c-PAH. The three models that we developed were associated with index of agreement approximately equal to 0.9, root mean square error < 2.6 ng/m3, and 90th percentile of absolute difference ≤ 4 ng/m3 for the predicted and the observed concentrations for eight pro-carcinogenic PAH. Conclusions Inexpensive and logistically feasible information could be used to estimate chronic personal exposure to PAH profiles, in lieu of costly and labor-intensive personal air monitoring at wide scale. At the same time, thorough validation through direct personal monitoring and assumption checking are critical for successful model development. PMID:25965038

  12. [Desorption of polycyclic aromatic hydrocarbons in soils assisted by SPMD].

    PubMed

    Sun, Hong-Wen; Huo, Chong; Wang, Cui-Ping

    2007-08-01

    In order to develop a new method to study the desorption and bioavailability of hydrophobic organic chemicals (HOCs) in soils, a method using semi-permeable membrane device (SPMD) to study desorption of HOCs in soils has been set up, and assisted desorption of polycyclic aromatic hydrocarbons (PAHs), phenanthrene(PHE), pyrene(PYE), and benzo[a] pyrene (B[a]PYE) in three different kinds of soils was studied using SPMD. The results show that SPMD is a good measurement to study the desorption and bioavailability of HOCs in soils. SPMD assisted desorption of PAHs is highly dependent on the properties of the soils and the chemicals. PHE and PYE desorption percentages increase with the reduction of the content of soil organic matter (SOM), so that the desorption of the two chemicals increases from 56.45% and 48.28% to almost 100% when SOM content was reduced from 18.68% to 0.3%. However, clay has a significant holding effect on B[a]PYE, and PYE desorption is only 66.97% in Soil 3 with SOM of 0.3% and clay content of 39.05%. There is a great variety in the desorption among the different PAHs. With the reduction of SOM content and the elevation of contamination concentration, the difference between PHE and PYE decreases gradually, while B[a]PYE exhibits a significant difference from them. This could be attributed to the high lipophilicity and large molecular size of B[a]PYE, which make the molecule of B[a]PYE to be more easier to be held in the nanopores of clay and the dense region of SOM.

  13. Human Colon Microbiota Transform Polycyclic Aromatic Hydrocarbons to Estrogenic Metabolites

    PubMed Central

    Van de Wiele, Tom; Vanhaecke, Lynn; Boeckaert, Charlotte; Peru, Kerry; Headley, John; Verstraete, Willy; Siciliano, Steven

    2005-01-01

    Ingestion is an important exposure route for polycyclic aromatic hydrocarbons (PAHs) to enter the human body. Although the formation of hazardous PAH metabolites by human biotransformation enzymes is well documented, nothing is known about the PAH transformation potency of human intestinal microbiota. Using a gastrointestinal simulator, we show that human intestinal microbiota can also bioactivate PAHs, more in particular to estrogenic metabolites. PAH compounds are not estrogenic, and indeed, stomach and small intestine digestions of 62.5 nmol naphthalene, phenanthrene, pyrene, and benzo(a)pyrene showed no estrogenic effects in the human estrogen receptor bioassay. In contrast, colon digests of these PAH compounds displayed estrogenicity, equivalent to 0.31, 2.14, 2.70, and 1.48 nmol 17α-ethynylestradiol (EE2), respectively. Inactivating the colon microbiota eliminated these estrogenic effects. Liquid chromatography–mass spectrometry analysis confirmed the microbial PAH transformation by the detection of PAH metabolites 1-hydroxypyrene and 7-hydroxybenzo(a)pyrene in colon digests of pyrene and benzo(a)pyrene. Furthermore, we show that colon digests of a PAH-contaminated soil (simulated ingestion dose of 5 g/day) displayed estrogenic activity equivalent to 0.58 nmol EE2, whereas stomach or small intestine digests did not. Although the matrix in which PAHs are ingested may result in lower exposure concentrations in the gut, our results imply that the PAH bioactivation potency of colon microbiota is not eliminated by the presence of soil. Moreover, because PAH toxicity is also linked to estrogenicity of the compounds, the PAH bioactivation potency of colon microbiota suggests that current risk assessment may underestimate the risk from ingested PAHs. PMID:15626640

  14. Polycyclic Aromatic Hydrocarbons and digestive tract cancers - a perspective

    PubMed Central

    Diggs, Deacqunita L.; Huderson, Ashley C.; Harris, Kelly L.; Myers, Jeremy N.; Banks, Leah D.; Rekhadevi, Perumalla V.; Niaz, Mohammad S.; Ramesh, Aramandla

    2011-01-01

    Cancers of the colon are most common in the Western world. In majority of these cases, there is no familial history and sporadic gene damage seems to play an important role in the development of tumors in the colon. Studies have shown that environmental factors, especially diet, play an important role in susceptibility to GI tract cancers. Consequently, environmental chemicals that contaminate food or diet during its preparation becomes important in the development of GI cancers. Polycyclic aromatic hydrocarbons (PAHs) are one such family of ubiquitous environmental toxicants. These pollutants enter the human body through consumption of contaminated food, drinking water, inhalation of cigarette smoke, automobile exhausts, and contaminated air from occupational settings. Among these pathways, dietary intake of PAHs constitutes a major source of exposure in humans. Although many reviews and books on PAHs and their ability to cause toxicity and breast or lung cancer have been published, aspects on contribution of diet, smoking and other factors towards development of digestive tract cancers and strategies to assess risk from exposure to PAHs have received much less attention. This review, therefore, focuses on dietary intake of PAHs in humans, animal models, and cell cultures used for GI cancer studies along with epidemiological findings. Bioavailability and biotransformation processes, which influence the disposition of PAHs in body and the underlying causative mechanisms of GI cancers, are also discussed. The existing data gaps and scope for future studies is also emphasized. This information is expected to stimulate research on mechanisms of sporadic GI cancers caused by exposure to environmental carcinogens. PMID:22107166

  15. Background'' soil concentration of polycyclic aromatic hydrocarbons from Burlington, Vermont

    SciTech Connect

    Parker, R.L.; Sparks, M.K. )

    1993-03-01

    Polycyclic Aromatic Hydrocarbons (PAH's) were identified in soils from waterfront industrial land in Burlington prior to conversion to a park. PAH's ranged from 2,457 to 16,005 ppb. As a result, this area was placed on the Vt. DEC list of active'' hazardous sites. The few studies available regarding background concentrations of PAH's (i.e. ATSDR, 1990), suggested that the waterfront PAH values were low for urban soils. To provide a context for evaluating the waterfront PAH concentrations, a background study of soils in the City of Burlington was conducted. Twelve composite soil samples were collected from within a 1-mile radius of the proposed park; an area that encompasses a large portion of the City. To correlate PAH concentrations with land-uses, three samples were collected from each of four zones: industrial, mixed commercial-residential, residential and recreational. Samples (and one field blank) were analyzed via EPA method 8100. Total PAH's from the study ranged from 105.7 to 122,035 ppb. The minimum value was from a baseball field; the maximum value from a residential lawn. The arithmetic mean for the Burlington study was 19,380 ppb (compared to 10,530 ppb for the waterfront). The background'' values indicate that the waterfront park soils are below the study background'' mean. It is difficult to assess the origin of the elevated PAH values because of the numerous contributors of environmental PAH. One common element that appears to characterize soils with the highest background'' PAH values is linkage to recent or historic building fires. In many instances building combustion may be a dominant local source of soil PAH's.

  16. Polycyclic aromatic hydrocarbons in mountain soils of the subtropical Atlantic.

    PubMed

    Ribes, A; Grimalt, J O; Torres García, C J; Cuevas, E

    2003-01-01

    Surface soil samples from various altitudes on Tenerife Island, ranging from sea level up to 3400 m above mean sea level, were analyzed to study the distribution of 26 polycyclic aromatic hydrocarbons (PAHs) in a remote subtropical area. The stable atmospheric conditions in this island define three vertically stratified layers: marine boundary, trade-wind inversion, and free troposphere. Total PAH concentrations, 1.9 to 6000 microg/kg dry wt., were high when compared with those in tropical areas and in a similar range to those in temperate areas. In the marine boundary layer, fluoranthene (Fla), pyrene (Pyr), benz [a]anthracene (BaA), and chrysene (C + T) were largely dominant. The predominance of Fla over Pyr may reflect photo-oxidative processes during atmospheric transport, although coal combustion inputs cannot be excluded. The PAHs found in higher concentration in the soils from the inversion layer were benzo[b + j]fluoranthene (BbjF) + benzo[k]fluoranthene (BkF) > benzo[e]pyrene (BeP) approximately indeno[1,2, 3-cd]pyrene (Ind) > benzo[a]pyrene (BaP) approximately benzo[ghi]perylene (Bghi) > coronene (Cor) approximately dibenz[a,h]anthracene (Dib), reflecting that high temperatures and insolation prevent the accumulation of PAHs more volatile than BbjF in significant amounts. These climatic conditions involve a process of standardization that prevents the identification of specific PAH sources such as traffic, forest fires, or industrial inputs. Only soils with high total organic carbon (TOC) (e.g., 10-30%) preserve the more volatile compounds such as phenanthrene (Phe), methylphenanthrenes (MPhe), dimethylphenanthrenes (DMPhe), and retene (Ret). However, no relation between PAHs and soil TOC and black carbon (BC) was found. The specific PAH distributions of the free tropospheric region suggest a direct input from pyrolytic processes related to the volcanic emission of gases in Teide.

  17. Dry deposition of polycyclic aromatic hydrocarbons in ambient air

    SciTech Connect

    Sheu, H.L.; Lee, W.J.; Su, C.C.; Chao, H.R.; Fan, Y.C.

    1996-12-01

    Dry deposition and air sampling were undertaken, simultaneously, in the ambient air of an urban site and a petrochemical-industry (PCI) plant by using several dry deposition plates and PS-1 samplers from January to May 1994 in southern Taiwan. The dry deposition plate with a smooth surface was always pointed into the wind. Twenty-one polycyclic aromatic hydrocarbons (PAHs) were analyzed by a gas chromatography/mass spectrometer (GC/MSD). The dry deposition flux of total-PAHs in urban and PCI sites averaged 166 and 211 {micro}g/m{sup 2}{center_dot}d, respectively. In general, the PAH dry deposition flux increased with increases in the PAH concentration in the ambient air. The PAH pattern of dry deposition flux in both urban and PCI sites were similar to the pattern measured by the filter of the PS-1 sampler and completely different from the PAH pattern in the gas phase. The higher molecular weight PAHs have higher dry deposition velocities. This is due to the fact that higher molecular weight PAHs primarily associated with the particle phase are deposited mostly by gravitational settling, while the gas phase PAHs were between 0.001 and 0.010 cm/s, only the lower molecular-weight PAHs--Nap and AcPy--had a significant fraction of dry deposition flux contributed by the gas phase. All the remaining higher molecular-weight PAHs had more than 94.5% of their dry deposition flux resulting from the particle phase. This is due to the fact that higher molecular weight PAHs have a greater fraction in the particle phase and the dry deposition velocities of particulates are much higher than those of the gas phase.

  18. Polycyclic Aromatic Hydrocarbons in Residential Dust: Sources of Variability

    PubMed Central

    Metayer, Catherine; Petreas, Myrto; Does, Monique; Buffler, Patricia A.; Rappaport, Stephen M.

    2013-01-01

    Background: There is interest in using residential dust to estimate human exposure to environmental contaminants. Objectives: We aimed to characterize the sources of variability for polycyclic aromatic hydrocarbons (PAHs) in residential dust and provide guidance for investigators who plan to use residential dust to assess exposure to PAHs. Methods: We collected repeat dust samples from 293 households in the Northern California Childhood Leukemia Study during two sampling rounds (from 2001 through 2007 and during 2010) using household vacuum cleaners, and measured 12 PAHs using gas chromatography–mass spectrometry. We used a random- and a mixed-effects model for each PAH to apportion observed variance into four components and to identify sources of variability. Results: Median concentrations for individual PAHs ranged from 10 to 190 ng/g of dust. For each PAH, total variance was apportioned into regional variability (1–9%), intraregional between-household variability (24–48%), within-household variability over time (41–57%), and within-sample analytical variability (2–33%). Regional differences in PAH dust levels were associated with estimated ambient air concentrations of PAH. Intraregional differences between households were associated with the residential construction date and the smoking habits of residents. For some PAHs, a decreasing time trend explained a modest fraction of the within-household variability; however, most of the within-household variability was unaccounted for by our mixed-effects models. Within-household differences between sampling rounds were largest when the interval between dust sample collections was at least 6 years in duration. Conclusions: Our findings indicate that it may be feasible to use residential dust for retrospective assessment of PAH exposures in studies of health effects. PMID:23461863

  19. Characterization of polycyclic aromatic hydrocarbons in fog-rain events.

    PubMed

    Li, Xiang; Li, Pengfei; Yan, Lili; Chen, Jianmin; Cheng, Tiantao; Xu, Shifen

    2011-11-01

    Atmospheric polycyclic aromatic hydrocarbons (PAHs) mainly originate from incomplete combustion or pyrolysis of materials containing carbon and hydrogen. They exist in gas and particle phases, as well as dissolved or suspended in precipitation (fog or rain). Current studies in atmospheric PAHs are predominantly focused on fog and rainwater samples. Some sampling difficulties are associated with fog samples. This study presented the first observation of the characteristics of PAHs in fog samples using a solid phase microextraction (SPME) technique. Eighteen fog samples were collected during ten fog events from March to December 2009 in the Shanghai area. PAHs were extracted by SPME and analyzed by gas chromatography-mass spectrometry (GC-MS). As the compounds were partially soluble in water, with solubility decreasing with increasing molecular weight, low molecular weight (LMW) PAH compounds were universally found in the fog water samples. Naphthalene (NaP), phenanthrene (Phe), anthracene (Ant) and fluoranthene (Flo) were dominant compounds in fog water. The total PAH concentration in fog water ranged from 0.03 to 6.67 μg L(-1) (mean of 1.06 μg L(-1)), and was much higher in winter than in summer. The concentration of PAHs in fog or rain water decreased after undergoing a pre-rain or pre-fog wash. The average concentration of PAHs was higher in fog than in rain. Diagnostic ratio analysis suggested that petroleum and combustion were the dominant contributors to PAHs in urban Shanghai. Backward trajectories were calculated to determine the origin of the air masses, showing that air masses were mostly from the northeast territory.

  20. Polycyclic aromatic hydrocarbons: from metabolism to lung cancer.

    PubMed

    Moorthy, Bhagavatula; Chu, Chun; Carlin, Danielle J

    2015-05-01

    Excessive exposure to polycyclic aromatic hydrocarbons (PAHs) often results in lung cancer, a disease with the highest cancer mortality in the United States. After entry into the lung, PAHs induce phase I metabolic enzymes such as cytochrome P450 (CYP) monooxygenases, i.e. CYP1A1/2 and 1B1, and phase II enzymes such as glutathione S-transferases, UDP glucuronyl transferases, NADPH quinone oxidoreductases (NQOs), aldo-keto reductases (AKRs), and epoxide hydrolases (EHs), via the aryl hydrocarbon receptor (AhR)-dependent and independent pathways. Humans can also be exposed to PAHs through diet, via consumption of charcoal broiled foods. Metabolism of PAHs through the CYP1A1/1B1/EH pathway, CYP peroxidase pathway, and AKR pathway leads to the formation of the active carcinogens diol-epoxides, radical cations, and o-quinones. These reactive metabolites produce DNA adducts, resulting in DNA mutations, alteration of gene expression profiles, and tumorigenesis. Mutations in xenobiotic metabolic enzymes, as well as polymorphisms of tumor suppressor genes (e.g. p53) and/or genes involved in gene expression (e.g. X-ray repair cross-complementing proteins), are associated with lung cancer susceptibility in human populations from different ethnicities, gender, and age groups. Although various metabolic activation/inactivation pathways, AhR signaling, and genetic susceptibilities contribute to lung cancer, the precise points at which PAHs induce tumor initiation remain unknown. The goal of this review is to provide a current state-of-the-science of the mechanisms of human lung carcinogenesis mediated by PAHs, the experimental approaches used to study this complex class of compounds, and future directions for research of these compounds.

  1. Intraperitoneal mesotheliomas induced in mice by a polycyclic aromatic hydrocarbon

    SciTech Connect

    Rice, J.M.; Anderson, L.M. ); Kovatch, R.M. )

    1989-01-01

    Female mice of 6 strains (C3H/HeN, BALB/c, C57BL/6N, DBA/2, NIH Swiss, and AKR/N) were given the polycyclic aromatic hydrocarbon carcinogen 3-methylcholanthrene (MC) intragastrically in olive oil at a dose of 20 mg/kg, weekly for 12 wk. Half were pretreated 24 h before each MC administration with intraperitoneal {beta}-naphthoflavone ({beta}-NF, 150 mg/kg in olive oil), a noncarinogenic inducer of certain cytochrome P-450 isozymes. Remaining mice were given olive oil prior to MC in the same fashion, or {beta}-NF in olive oil or olive oil alone without subsequent exposure to MC. All mice were killed when moribund or 13 mo after the start of treatment. Most of the mice, irrespective of treatment, exhibited signs of peritoneal injury, including inflammation, necrosis, granuloma formation, and mineralization. Mice of some of the strains also presented peritoneal mesotheliomas, in addition to a variety of other tumors. {beta}-NF pretreatment reduced the frequency of mesotheliomas: there was only one definite mesothelioma in any of the {beta}-NF-MC groups, in a C3H/He mouse. Most of the measotheliomas were mixed fibro-mesothelial type, sometimes with papillary epithelial excrescences. They typically grew in a botryoid pattern within the peritoneal cavity, coating the abdominal organs and sometimes actively invading these organs and the diaphragm. Some lesions exhibited pleomorphism, prominent giant cells, and frequent mitoses. In addition, several lesions consisting of severe mesothelial hyperplasia associated with tissue necrosis and inflammation were considered as possible early stages of mesothelioma development. It was postulated that peritoneal injury imposed by repeated intraperitoneal injection of oil acted as an enhancing factor for mesothelioma induction by MC.

  2. Infrared Spectroscopy of Polycyclic Aromatic Hydrocarbon Cations. 3; The Members

    NASA Technical Reports Server (NTRS)

    Hudgins, D. M.; Allamandola, L. J.; Wittebon, Fred C. (Technical Monitor)

    1994-01-01

    In spite of the fact that the infrared spectroscopic properties of only a few isolated ionized polycyclic aromatic hydrocarbons (PAHs) are known, gaseous, ionized PAHs are thought to be responsible for a very common family of infrared interstellar emission bands. In order to provide a data base to test this hypothesis and, if borne out, to use this emission band family as a probe of many different interstellar environments, we are carrying out a thorough study of the infrared spectroscopic properties of neutral and ionized PAHs in argon matrices. Here we present the near and mid-infrared spectra of the cations of the five most thermodynamically favored PAHs up to coronene: phenanthrene, pyrene, benzo[e]pyrene, benzo[ghilperylene, and coronene. The properties of naphthalene, the first member of the series, are given elsewhere. The spectra of perdeuterated phenanthrene and pyrene are also reported. For those molecules which have been previously studied (pyrene, d(10)-pyrene, and coronene), band positions and relative intensities are in agreement. In all cases we report additional features. Absolute integrated absorbance values are given for the phenanthrene, perdeutero-phenanthrene, pyrene, benzo[ghi]perylene, and coronene cations. With the exception of coronene,the cation bands corresponding to the CC modes are typically 2-5 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 5-20 times weaker than in the neutral species. This behavior is similar to that found in most other PAH cations studied to date. The astronomical implications of these PAH cation spectra are also discussed.

  3. Polycyclic aromatic hydrocarbon ecotoxicity data for developing soil quality criteria.

    PubMed

    Jensen, John; Sverdrup, Line E

    2003-01-01

    With the overall perspective of calculating soil quality criteria (SQC) for the group of polycyclic aromatic hydrocarbons (PAHs), the existing ecotoxicity data for the soil compartment have been reviewed. The majority of data useful in the context of deriving SQC are of recent origin. Soil quality criteria are considered valuable tools for assessing the environmental risk of contamination, as they may give guidance on concentration limits for various chemicals to protect the function and structure of ecosystems. Soil quality criteria for soil-dwelling species were calculated using various assumptions and two internationally accepted methods, i.e., application of assessment factors and species sensitivity distributions, respectively. It was suggested to derive ecotoxicological soil quality criteria, which focus on the lower molecular weight PAHs, i.e., those with log Kow values lower than 5.5 or 6; this is the log Kow range where a cutoff in toxicity for terrestrial species is expected for narcotic substances. Predicted values from the two methods were similar. Calculations showed that, for four individual PAHs of three or four rings, SQC fall in the range of 1.0 and 2.5 mg kg(-1). However, as no individual PAH is fond alone it is suggested to use a sum criterion for a group of PAHs instead. The different possibilities to calculate such a sum criterion are discussed. Based on toxicity data presented here and the average abundance of different PAHs in nearly 1000 Danish soil samples, an ecotoxicological soil quality criterion of 25 mg kg(-1) dry weight for the sum of the eight PAHs acenaphthene, fluorene, anthracene, phenanthrene, pyrene, fluoranthene, benz[a]anthracene, and chrysene is suggested.

  4. Fluorescence Spectroscopy of Gas-phase Polycyclic Aromatic Hydrocarbons

    NASA Technical Reports Server (NTRS)

    Thomas, J. D.; Witt, A. N.

    2006-01-01

    The purpose of this investigation was to produce fluorescence spectra of polycyclic aromatic hydrocarbon (PAH) molecules in the gas-phase for comparison with blue luminescence (BL) emission observed in astrophysical sources Vijh et al. (2004, 2005a,b). The BL occurs roughly from 350 to 450 nm, with a sharp peak near 380 nm. PAHs with three to four rings, e.g. anthracene and pyrene, were found to produce luminescence in the appropriate spectral region, based on existing studies. Relatively few studies of the gas-phase fluorescence of PAHs exist; those that do exist have dealt primarily with the same samples commonly available for purchase such as pyrene and anthracene. In an attempt to understand the chemistry of the nebular environment we also obtained several nitrogen substituted PAHs from our colleagues at NASA Ames. In order to simulate the astrophysical environment we also took spectra by heating the PAHs in a flame. The flame environment counteracts the formation of eximers and permits the spectroscopy of free-flying neutral molecules. Experiments with coal tar demonstrate that fluorescence spectroscopy reveals primarily the presence of the smallest molecules, which are most abundant and which possess the highest fluorescence efficiencies. One gas-phase PAH that seems to fit the BL spectrum most closely is phenanthridine. In view of the results from the spectroscopy of coal tar, a compound containing a mixture of PAHs ranging from small to very large PAH molecules, we can not preclude the presence of larger PAHs in interstellar sources exhibiting BL.

  5. Human colon microbiota transform polycyclic aromatic hydrocarbons to estrogenic metabolites.

    PubMed

    Van de Wiele, Tom; Vanhaecke, Lynn; Boeckaert, Charlotte; Peru, Kerry; Headley, John; Verstraete, Willy; Siciliano, Steven

    2005-01-01

    Ingestion is an important exposure route for polycyclic aromatic hydrocarbons (PAHs) to enter the human body. Although the formation of hazardous PAH metabolites by human biotransformation enzymes is well documented, nothing is known about the PAH transformation potency of human intestinal microbiota. Using a gastrointestinal simulator, we show that human intestinal microbiota can also bioactivate PAHs, more in particular to estrogenic metabolites. PAH compounds are not estrogenic, and indeed, stomach and small intestine digestions of 62.5 nmol naphthalene, phenanthrene, pyrene, and benzo(a)pyrene showed no estrogenic effects in the human estrogen receptor bioassay. In contrast, colon digests of these PAH compounds displayed estrogenicity, equivalent to 0.31, 2.14, 2.70, and 1.48 nmol 17alpha-ethynylestradiol (EE2), respectively. Inactivating the colon microbiota eliminated these estrogenic effects. Liquid chromatography-mass spectrometry analysis confirmed the microbial PAH transformation by the detection of PAH metabolites 1-hydroxypyrene and 7-hydroxybenzo(a)pyrene in colon digests of pyrene and benzo(a)pyrene. Furthermore, we show that colon digests of a PAH-contaminated soil (simulated ingestion dose of 5 g/day) displayed estrogenic activity equivalent to 0.58 nmol EE2, whereas stomach or small intestine digests did not. Although the matrix in which PAHs are ingested may result in lower exposure concentrations in the gut, our results imply that the PAH bioactivation potency of colon microbiota is not eliminated by the presence of soil. Moreover, because PAH toxicity is also linked to estrogenicity of the compounds, the PAH bioactivation potency of colon microbiota suggests that current risk assessment may underestimate the risk from ingested PAHs.

  6. Identification and discrimination of polycyclic aromatic hydrocarbons using Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Cloutis, Edward; Szymanski, Paul; Applin, Daniel; Goltz, Douglas

    2016-08-01

    Polycyclic aromatic hydrocarbons (PAHs) are widely present throughout the Solar System and beyond. They have been implicated as a contributor to unidentified infrared emission bands in the interstellar medium, comprise a substantial portion of the insoluble organic matter in carbonaceous chondrites, are expected stable components of organic matter on Mars, and are present in a wide range of terrestrial hydrocarbons and as components of biomolecules. However, PAH structures can be very complicated, making their identification challenging. Raman spectroscopy is known to be especially sensitive to the highly polarizable C-C and C=C bonds found in PAHs, and therefore, can be a powerful tool for PAH structural and compositional elucidation. This study examined Raman spectra of 48 different PAHs to determine the degree to which Raman spectroscopy could be used to uniquely identify different species, factors that control the positions of major Raman peaks, the degree to which induced fluorescence affects the intensity of Raman peaks, its usefulness for PAH discrimination, and the effects of varying excitation wavelength on some PAH Raman spectra. It was found that the arrangement and composition of phenyl (benzene) rings, and the type and position of functional groups can greatly affect fluorescence, positions and intensities of Raman peaks associated with the PAH backbone, and the introduction of new Raman peaks. Among the functional groups found on many of the PAHs that were analyzed, only a few Raman peaks corresponding to the molecular vibrations of these groups could be clearly distinguished. Comparison of the PAH Raman spectra that were acquired with both 532 and 785 nm excitation found that the longer wavelength resulted in reduced fluorescence, consistent with previous studies.

  7. Polycyclic aromatic hydrocarbons and heavy metals in Kostrena coastal area.

    PubMed

    Linsak, Dijana Tomić; Linsak, Zeljko; Besić, Denis; Vojcić, Nina; Telezar, Mirna; Coklo, Miran; Susnić, Sasa; Mićović, Vladimir

    2011-12-01

    The aim of this study was to determine pollution by polycyclic aromatic hydrocarbons (PAH) and heavy metals in seawater and sediment in Kostrena coastal area, as well as their toxicity using bioluminescence based tests. Total PAH concentration in seawater ranged 1.7-155.3 ng/L. The share of carcinogenetic PAH was relatively high, ranging 22-48.3%. Nickel concentrations in seawater were beyond detection limits (< 0.1 microg/L), vanadium concentrations ranged 0.66-1.96 microg/L, chrome concentrations were beyond detection limits, and copper concentrations were also beyond detection limits or extremely low (up to 0.32 microg/L). EC50 values in seawater ranged 23.80-90.90 ng/L. Correlation between total PAH concentration and toxicity of seawater showed strong connection between them (r = 0.9579). Total PAH concentration in marine sediment ranged 58.02-1116 microg/kg dry weight (d.w.). The share of carcinogenetic PAH was extremely high ranging 10-53%. Nickel concentrations in marine sediment ranged 8-24 mg/kg d.w., vanadium concentrations ranged 24-42 mg/kg d.w., chrome concentrations ranged 11-19 mg/kg d.w., and copper concentrations ranged 7-25 mg/kg d.w. EC50 values in marine sediment ranged 818-4596 microg/kg d.w. Correlation between total PAH concentration and toxicity of marine sediment showed weak connection between them (r = 0.2590). Previous studies of seawater samples from areas of the Adriatic sea under the direct influence of oil industry did not include concentrations of heavy metals, which makes our study the first to present such comprehensive results. Our results point out the need for further evaluations and following of marine environment pollution and its consequences on living organisms and marine ecosystem in whole.

  8. Exposure to polycyclic aromatic hydrocarbons among Dutch children.

    PubMed

    van Wijnen, J H; Slob, R; Jongmans-Liedekerken, G; van de Weerdt, R H; Woudenberg, F

    1996-05-01

    We determined the urinary 1-hydroxypyrene (1-HP) concentration and the creatinine-adjusted 1-HP concentration in 644 randomly selected Dutch children, aged 1-6 years and living in five areas with roughly different levels of polycyclic aromatic hydrocarbons (PAHs) in soil and ambient air. The presence of other factors that might influence the exposure to PAHs was studied using a questionnaire. To evaluate the reliability of a single urinary 1-HP determination, measurements were repeated after 3 weeks for approximately 200 children. The mean urinary 1-HP content of the total study population was 2.06 nmol/l. This varied from 1.58 nmol/l in the reference area (Flevoland) to 2.71 nmol/l in the valley of the Geul. Only indoor sources of PAHs showed a small, positive association with urinary 1-HP. The urinary 1-HP concentrations of children from the valley of the Geul were higher (p < 0.01) and those of children from a suburb of Amsterdam were lower (p < 0.01) than those of children from the reference area. The possible ambient environment-related differences were probably too small to be detected in the variations of the intake of PAHs from the daily diet. The reliability of a single 1-HP measurement was low. Similar results were obtained with the creatinine-adjusted data. In one neighborhood built on coal-mine tailings, the urinary 1-HP content in children was weakly but positively associated with the PAH content in the upper soil layer of the garden of their homes. However, this association was not found for the children from the other neighborhood built on coal-mine tailings and with similar PAH levels in soil.

  9. Sorption of polycyclic aromatic hydrocarbons (PAHs) on glass surfaces.

    PubMed

    Qian, Yuan; Posch, Tjorben; Schmidt, Torsten C

    2011-02-01

    Sorption of polycyclic aromatic hydrocarbons (PAHs) to glass commonly used in laboratories was studied. Sorption coefficients (Kd) of five selected PAHs to borosilicate glass surfaces were measured using column chromatography. A linear relationship between log Kd and the corresponding water solubility of the subcooled liquid (log Sw) of the investigated PAHs was observed. Based on the determined sorption coefficients our data revealed that mass loss caused by sorption on glass walls strongly depends on the ratio of solution volume to contacted surface area (V/S). The influence of solution chemistry such as ionic strength, solution pH, presence of cosolvent, and the influence of temperature on the sorption process were investigated. In the presence of ionic strength, sorption coefficients concurrently increased but less than a factor of 2 up to 0.005 M calcium chloride concentration. However, further increasing ionic strength had no influence on Kd. The cosolvent reduced sorption at a concentration of methanol in water above 0.5% (v/v); however, for benzo[a]pyrene even with 10% (v/v) methanol the mass loss would be still higher than 10% (with a V/S ratio less than 0.25). Significant effects of the solution pH and temperature were not observed. These results suggest that van der Waal's forces dominate the sorption process. In the analysis of highly hydrophobic PAHs in aqueous samples, mass loss due to sorption on glass walls should be accounted for in the final result if untreated glass is used. The presented relationship between log Kd and log Sw may help to decide if such a correction is necessary. Furthermore, the frequently used silanization of glass surfaces may not be sufficient to suppress sorption for large PAHs.

  10. Dissociation of polycyclic aromatic hydrocarbons: molecular dynamics studies

    NASA Astrophysics Data System (ADS)

    Simon, A.; Rapacioli, M.; Rouaut, G.; Trinquier, G.; Gadéa, F. X.

    2017-03-01

    We present dynamical studies of the dissociation of polycyclic aromatic hydrocarbon (PAH) radical cations in their ground electronic states with significant internal energy. Molecular dynamics simulations are performed, the electronic structure being described on-the-fly at the self-consistent-charge density functional-based tight binding (SCC-DFTB) level of theory. The SCC-DFTB approach is first benchmarked against DFT results. Extensive simulations are achieved for naphthalene , pyrene and coronene at several energies. Such studies enable one to derive significant trends on branching ratios, kinetics, structures and hints on the formation mechanism of the ejected neutral fragments. In particular, dependence of branching ratios on PAH size and energy were retrieved. The losses of H and C2H2 (recognized as the ethyne molecule) were identified as major dissociation channels. The H/C2H2 ratio was found to increase with PAH size and to decrease with energy. For , which is the most interesting PAH from the astrophysical point of view, the loss of H was found as the quasi-only channel for an internal energy of 30 eV. Overall, in line with experimental trends, decreasing the internal energy or increasing the PAH size will favour the hydrogen loss channels with respect to carbonaceous fragments. This article is part of the themed issue 'Theoretical and computational studies of non-equilibrium and non-statistical dynamics in the gas phase, in the condensed phase and at interfaces'.

  11. Ambient polycyclic aromatic hydrocarbons and pulmonary function in children

    PubMed Central

    Padula, Amy M.; Balmes, John R.; Eisen, Ellen A.; Mann, Jennifer; Noth, Elizabeth M.; Lurmann, Frederick W.; Pratt, Boriana; Tager, Ira B.; Nadeau, Kari; Hammond, S. Katharine

    2014-01-01

    Few studies have examined the relationship between ambient polycyclic aromatic hydrocarbons (PAHs) and pulmonary function in children. Major sources include vehicular emissions, home heating, wildland fires, agricultural burning, and power plants. PAHs are an important component of fine particulate matter that has been linked to respiratory health. This cross-sectional study examines the relationship between estimated individual exposures to the sum of PAHs with 4, 5, or 6 rings (PAH456) and pulmonary function tests (forced expiratory volume in one second (FEV1) and forced expiratory flow between 25% and 75% of vital capacity) in asthmatic and non-asthmatic children. We applied land-use regression to estimate individual exposures to ambient PAHs for averaging periods ranging from 1 week to 1 year. We used linear regression to estimate the relationship between exposure to PAH456 with pre- and postbronchodilator pulmonary function tests in children in Fresno, California (N =297). Among non-asthmatics, there was a statistically significant association between PAH456 during the previous 3 months, 6 months, and 1 year and postbronchodilator FEV1. The magnitude of the association increased with the length of the averaging period ranging from 60 to 110 ml decrease in FEV1 for each 1 ng/m3 increase in PAH456. There were no associations with PAH456 observed among asthmatic children. We identified an association between annual PAHs and chronic pulmonary function in children without asthma. Additional studies are needed to further explore the association between exposure to PAHs and pulmonary function, especially with regard to differential effects between asthmatic and non-asthmatic children. PMID:24938508

  12. Polycyclic aromatic hydrocarbons in surface sediments of the Jialu River.

    PubMed

    Fu, Jie; Sheng, Sheng; Wen, Teng; Zhang, Zhi-Ming; Wang, Qing; Hu, Qiu-Xiang; Li, Qing-Shan; An, Shu-Qing; Zhu, Hai-Liang

    2011-07-01

    The Jialu River, an important branch of the Huaihe River in China, was seriously polluted because of rapid economic growth and urbanization. In order to evaluate the potential for serious environmental consequences as a result of anthropogenic contamination, the distribution of polycyclic aromatic hydrocarbons (PAHs) has been investigated in surface sediment samples collected in connection with field surveys of 19 sites along the Jialu River. The total concentration of the 16 USEPA priority PAHs ranged from 466.0 to 2605.6 ng/g dry weight with a mean concentration of 1363.2 ng/g. Sediment samples with the highest PAH concentrations were from the upper reaches of the river, where Zhengzhou City is located; the PAH levels in the middle and lower reaches were relatively low. According to the observed molecular indices, PAHs originated largely from the high-temperature pyrolytic process. According to the numerical effect-based sediment quality guidelines (SQGs) of the United States, the levels of PAHs in the Jialu River should not exert adverse biological effects. The total benzo[a]pyrene toxicity equivalent (TEQ) values calculated for samples varied from 50.4 to 312.8 ng/g dry weight with an average of 167.4 ng/g. The relationships between PAHs and environmental factors, including chemical properties of sediments, water quality, aquatic organisms, hydrological conditions, and anthropogenic activities, are also discussed. PAHs exerted a potential negative impact on the benthos. Settlement percentage, population density and industrial GDP per capita had a significant influence on the distribution of PAHs.

  13. Generation of polycyclic aromatic hydrocarbons (PAHs) during woodworking operations

    PubMed Central

    Bruschweiler, Evin D.; Danuser, Brigitta; Huynh, Cong Khanh; Wild, Pascal; Schupfer, Patrick; Vernez, David; Boiteux, Philippe; Hopf, Nancy B.

    2012-01-01

    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 wood working operations, PAH 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 three 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 personal sampler device during wood working operations. We measured 21 PAH concentrations in wood dust samples by capillary gas chromatography-ion trap mass spectrometry (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 PAH exposures were between 37.5–119.8 ng m−3 during wood working operations. Our results suggest that PAH exposures are present during woodworking operations and hence could play a role in the mechanism of cancer induction related to wood dust exposure. PMID:23087908

  14. Polycyclic Aromatic Hydrocarbons: From Metabolism to Lung Cancer

    PubMed Central

    Moorthy, Bhagavatula; Chu, Chun; Carlin, Danielle J.

    2015-01-01

    Excessive exposure to polycyclic aromatic hydrocarbons (PAHs) often results in lung cancer, a disease with the highest cancer mortality in the United States. After entry into the lung, PAHs induce phase I metabolic enzymes such as cytochrome P450 (CYP) monooxygenases, i.e. CYP1A1/2 and 1B1, and phase II enzymes such as glutathione S-transferases, UDP glucuronyl transferases, NADPH quinone oxidoreductases (NQOs), aldo-keto reductases (AKRs), and epoxide hydrolases (EHs), via the aryl hydrocarbon receptor (AhR)-dependent and independent pathways. Humans can also be exposed to PAHs through diet, via consumption of charcoal broiled foods. Metabolism of PAHs through the CYP1A1/1B1/EH pathway, CYP peroxidase pathway, and AKR pathway leads to the formation of the active carcinogens diol-epoxides, radical cations, and o-quinones. These reactive metabolites produce DNA adducts, resulting in DNA mutations, alteration of gene expression profiles, and tumorigenesis. Mutations in xenobiotic metabolic enzymes, as well as polymorphisms of tumor suppressor genes (e.g. p53) and/or genes involved in gene expression (e.g. X-ray repair cross-complementing proteins), are associated with lung cancer susceptibility in human populations from different ethnicities, gender, and age groups. Although various metabolic activation/inactivation pathways, AhR signaling, and genetic susceptibilities contribute to lung cancer, the precise points at which PAHs induce tumor initiation remain unknown. The goal of this review is to provide a current state-of-the-science of the mechanisms of human lung carcinogenesis mediated by PAHs, the experimental approaches used to study this complex class of compounds, and future directions for research of these compounds. PMID:25911656

  15. Polycyclic aromatic hydrocarbons and digestive tract cancers: a perspective.

    PubMed

    Diggs, Deacqunita L; Huderson, Ashley C; Harris, Kelly L; Myers, Jeremy N; Banks, Leah D; Rekhadevi, Perumalla V; Niaz, Mohammad S; Ramesh, Aramandla

    2011-10-01

    Cancers of the colon are most common in the Western world. In majority of these cases, there is no familial history and sporadic gene damage seems to play an important role in the development of tumors in the colon. Studies have shown that environmental factors, especially diet, play an important role in susceptibility to gastrointestinal (GI) tract cancers. Consequently, environmental chemicals that contaminate food or diet during preparation become important in the development of GI cancers. Polycyclic aromatic hydrocarbons (PAHs) are one such family of ubiquitous environmental toxicants. These pollutants enter the human body through consumption of contaminated food, drinking water, inhalation of cigarette smoke, automobile exhausts, and contaminated air from occupational settings. Among these pathways, dietary intake of PAHs constitutes a major source of exposure in humans. Although many reviews and books on PAHs and their ability to cause toxicity and breast or lung cancer have been published, aspects on contribution of diet, smoking and other factors toward development of digestive tract cancers, and strategies to assess risk from exposure to PAHs have received much less attention. This review, therefore, focuses on dietary intake of PAHs in humans, animal models, and cell cultures used for GI cancer studies along with epidemiological findings. Bioavailability and biotransformation processes, which influence the disposition of PAHs in body and the underlying causative mechanisms of GI cancers, are also discussed. The existing data gaps and scope for future studies is also emphasized. This information is expected to stimulate research on mechanisms of sporadic GI cancers caused by exposure to environmental carcinogens.

  16. Phototoxic target lipid model of single polycyclic aromatic hydrocarbons.

    PubMed

    Marzooghi, Solmaz; Finch, Bryson E; Stubblefield, William A; Dmitrenko, Olga; Neal, Sharon L; Di Toro, Dominic M

    2017-04-01

    A phototoxic target lipid model (PTLM) is developed to predict phototoxicity of individual polycyclic aromatic hydrocarbons (PAHs) measured either as median lethal concentration (LC50) or median lethal time (LT50) for a 50% toxic response. The model is able to account for the differences in the physical/chemical properties of PAHs, test species sensitivities, and variations in light source characteristics, intensity, and length of exposure. The PTLM is based on the narcotic target lipid model (NTLM) of PAHs. Both models rely on the assumption that mortality occurs when the toxicant concentration in the target lipid of the organism reaches a threshold concentration. The PTLM is applied to observed LC50s and LT50s for 20 individual PAHs, 15 test species-including arthropods, fishes, amphibians, annelids, mollusks, and algae-exposed to simulated solar and various UV light sources, for exposure times varying from less than 1 h to 100 h, a total of 333 observations. The LC50 concentrations range from less than 0.1 µg/L to greater that 10(4)  µg/L. The model has 2 fitting parameters that are constant and apply to all PAHs and organisms. The root mean square errors of prediction for log(LC50) and log(LT50) are 0.473 and 0.382, respectively. The results indicate that the PTLM can predict the phototoxicity of single PAHs over a wide range of exposure conditions and to organisms with a wide range of sensitivities. Environ Toxicol Chem 2017;36:926-937. © 2016 SETAC. © 2016 SETAC.

  17. Infrared Spectroscopy of Polycyclic Aromatic Hydrocarbon Cations. 3; The Members

    NASA Technical Reports Server (NTRS)

    Hudgins, D. M.; Allamandola, L. J.; Wittebon, Fred C. (Technical Monitor)

    1994-01-01

    In spite of the fact that the infrared spectroscopic properties of only a few isolated ionized polycyclic aromatic hydrocarbons (PAHs) are known, gaseous, ionized PAHs are thought to be responsible for a very common family of infrared interstellar emission bands. In order to provide a data base to test this hypothesis and, if borne out, to use this emission band family as a probe of many different interstellar environments, we are carrying out a thorough study of the infrared spectroscopic properties of neutral and ionized PAHs in argon matrices. Here we present the near and mid-infrared spectra of the cations of the five most thermodynamically favored PAHs up to coronene: phenanthrene, pyrene, benzo[e]pyrene, benzo[ghilperylene, and coronene. The properties of naphthalene, the first member of the series, are given elsewhere. The spectra of perdeuterated phenanthrene and pyrene are also reported. For those molecules which have been previously studied (pyrene, d(10)-pyrene, and coronene), band positions and relative intensities are in agreement. In all cases we report additional features. Absolute integrated absorbance values are given for the phenanthrene, perdeutero-phenanthrene, pyrene, benzo[ghi]perylene, and coronene cations. With the exception of coronene,the cation bands corresponding to the CC modes are typically 2-5 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 5-20 times weaker than in the neutral species. This behavior is similar to that found in most other PAH cations studied to date. The astronomical implications of these PAH cation spectra are also discussed.

  18. Ambient polycyclic aromatic hydrocarbons and pulmonary function in children.

    PubMed

    Padula, Amy M; Balmes, John R; Eisen, Ellen A; Mann, Jennifer; Noth, Elizabeth M; Lurmann, Frederick W; Pratt, Boriana; Tager, Ira B; Nadeau, Kari; Hammond, S Katharine

    2015-05-01

    Few studies have examined the relationship between ambient polycyclic aromatic hydrocarbons (PAHs) and pulmonary function in children. Major sources include vehicular emissions, home heating, wildland fires, agricultural burning, and power plants. PAHs are an important component of fine particulate matter that has been linked to respiratory health. This cross-sectional study examines the relationship between estimated individual exposures to the sum of PAHs with 4, 5, or 6 rings (PAH456) and pulmonary function tests (forced expiratory volume in one second (FEV1) and forced expiratory flow between 25% and 75% of vital capacity) in asthmatic and non-asthmatic children. We applied land-use regression to estimate individual exposures to ambient PAHs for averaging periods ranging from 1 week to 1 year. We used linear regression to estimate the relationship between exposure to PAH456 with pre- and postbronchodilator pulmonary function tests in children in Fresno, California (N=297). Among non-asthmatics, there was a statistically significant association between PAH456 during the previous 3 months, 6 months, and 1 year and postbronchodilator FEV1. The magnitude of the association increased with the length of the averaging period ranging from 60 to 110 ml decrease in FEV1 for each 1 ng/m(3) increase in PAH456. There were no associations with PAH456 observed among asthmatic children. We identified an association between annual PAHs and chronic pulmonary function in children without asthma. Additional studies are needed to further explore the association between exposure to PAHs and pulmonary function, especially with regard to differential effects between asthmatic and non-asthmatic children.

  19. STRONG POLYCYCLIC AROMATIC HYDROCARBON EMISSION FROM z {approx} 2 ULIRGs

    SciTech Connect

    Desai, Vandana; Soifer, B. T.; Melbourne, Jason; Dey, Arjun; Brand, Kate; Brodwin, Mark; Jannuzi, Buell T.; Le Floc'h, Emeric; Armus, Lee; Teplitz, Harry; Brown, Michael J. I.; Houck, James R.; Weedman, Daniel W.; Ashby, Matthew L. N.; Huang Jiasheng; Smith, Howard A.; Willner, Steve P.; Gonzalez, Anthony

    2009-08-01

    Using the Infrared Spectrograph on board the Spitzer Space Telescope, we present low-resolution (64 < {lambda}/{delta}{lambda} < 124), mid-infrared (20-38 {mu}m) spectra of 23 high-redshift ULIRGs detected in the Booetes field of the NOAO Deep Wide-Field Survey. All of the sources were selected to have (1) f {sub {nu}}(24 {mu}m)>0.5 mJy; (2) R - [24]>14 Vega mag; and (3) a prominent rest frame 1.6 {mu}m stellar photospheric feature redshifted into Spitzer's 3-8 {mu}m IRAC bands. Of these, 20 show emission from polycyclic aromatic hydrocarbons (PAHs), usually interpreted as signatures of star formation. The PAH features indicate redshifts in the range 1.5 < z < 3.0, with a mean of (z) = 1.96 and a dispersion of 0.30. Based on local templates, these sources have extremely large infrared luminosities, comparable to that of submillimeter galaxies. Our results confirm previous indications that the rest-frame 1.6 {mu}m stellar bump can be efficiently used to select highly obscured star-forming galaxies at z {approx} 2, and that the fraction of starburst-dominated ULIRGs increases to faint 24 {mu}m flux densities. Using local templates, we find that the observed narrow redshift distribution is due to the fact that the 24 {mu}m detectability of PAH-rich sources peaks sharply at z = 1.9. We can analogously use observed spectral energy distributions to explain the broader redshift distribution of Spitzer-detected ULIRGs that are dominated by an active galactic nucleus (AGN). Finally, we conclude that z {approx} 2 sources with a detectable 1.6 {mu}m stellar opacity feature lack sufficient AGN emission to veil the 7.7 {mu}m PAH band.

  20. Sorption characteristics of polycyclic aromatic hydrocarbons in aluminum smelter residues

    SciTech Connect

    Gijs D. Breedveld; Emilien Pelletier; Richard St. Louis; Gerard Cornelissen

    2007-04-01

    High temperature carbon oxidation in primary aluminum smelters results in the release of polycyclic aromatic hydrocarbons (PAH) into the environment. The main source of PAH are the anodes, which are composed of petroleum coke (black carbon, BC) and coal tar pitch. To elucidate the dominant carbonaceous phase controlling the environmental fate of PAH in aluminum smelter residues (coke BC and/or coal tar), the sorptive behavior of PAHs has been determined, using passive samplers and infinite-sink desorption methods. Samples directly from the wet scrubber were studied as well as ones from an adjacent 20-year old storage lagoon and roof dust from the smelter. Carbon-normalized distribution coefficients of native PAHs were 2 orders of magnitude higher than expected based on amorphous organic carbon (AOC)/water partitioning, which is in the same order of magnitude as reported literature values for soots and charcoals. Sorption isotherms of laboratory-spiked deuterated phenanthrene showed strong (about 100 times stronger than AOC) but nonetheless linear sorption in both fresh and aged aluminum smelter residues. The absence of nonlinear behavior typical for adsorption to BC indicates that PAH sorption in aluminum smelter residues is dominated by absorption into the semi-solid coal tar pitch matrix. Desorption experiments using Tenax showed that fresh smelter residues had a relatively large rapidly desorbing fraction of PAH (35-50%), whereas this fraction was strongly reduced (11-16%) in the lagoon and roof dust material. Weathering of the coal tar residue and/or redistribution of PAH between coal tar and BC phases could explain the reduced availability in aged samples. 38 refs., 5 figs., 1 tab.

  1. High levels of carcinogenic polycyclic aromatic hydrocarbons in mate drinks.

    PubMed

    Kamangar, Farin; Schantz, Michele M; Abnet, Christian C; Fagundes, Renato B; Dawsey, Sanford M

    2008-05-01

    Drinking mate has been associated with cancers of the esophagus, oropharynx, larynx, lung, kidney, and bladder. We conducted this study to determine whether drinking mate could lead to substantial exposure to polycyclic aromatic hydrocarbons (PAH), including known carcinogens, such as benzo[a]pyrene. The concentrations of 21 individual PAHs were measured in dry leaves of eight commercial brands of yerba mate and in infusions made with hot (80 degrees C) or cold (5 degrees C) water. Measurements were done using gas chromatography/mass spectrometry, with deuterated PAHs as the surrogates. Infusions were made by adding water to the leaves, removing the resulting infusion after 5 min, and then adding more water to the remaining leaves. This process was repeated 12 times for each infusion temperature. The total concentrations of the 21 PAHs in different brands of yerba mate ranged from 536 to 2,906 ng/g dry leaves. Benzo[a]pyrene concentrations ranged from 8.03 to 53.3 ng/g dry leaves. For the mate infusions prepared using hot water and brand 1, 37% (1,092 of 2,906 ng) of the total measured PAHs and 50% (25.1 of 50 ng) of the benzo[a]pyrene content were released into the 12 infusions. Similar results were obtained for other hot and cold infusions. Very high concentrations of carcinogenic PAHs were found in yerba mate leaves and in hot and cold mate infusions. Our results support the hypothesis that the carcinogenicity of mate may be related to its PAH content.

  2. Exposure to polycyclic aromatic hydrocarbons among Dutch children

    SciTech Connect

    Wijnen, J.H. van; Slob, R.; Jongmans-Liedekerken, G.

    1996-05-01

    We determined the urinary 1-hydroxypyrene (1-HP) concentration and the creatinine-adjusted 1-HP concentration in 644 randomly selected Dutch children, aged 1-6 years and living in five areas with roughly different levels of polycyclic aromatic hydrocarbons (PAHs) in soil and ambient air. The presence of other factors that might influence the exposure to PAHs was studied using a questionnaire. To evaluate the reliability of a single urinary 1-HP determination, measurements were repeated after 3 weeks for approximately 200 children. The mean urinary 1-HP content of the total study population was 2.06 nmol/1. This varied from 1.58 nmol/l in the reference area (Flevoland) to 2.71 nmol/l in the valley of the Geul. Only indoor sources of PAHs showed a small, positive association with urinary 1-HP. The urinary 1-HP concentrations of children from the valley of the Geul were higher (p<0.01) and those of children from a suburb of Amsterdam were lower (p<0.01) than those of children from the reference area. The possible ambient environment-related differences were probably too small to be detected in the variations of the intake of PAHs from the daily diet. The reliability of a single 1-HP measurement was low. Similar results were obtained with the creatinine-adjusted data. In one neighborhood built on coal-mine tailings, the urinary 1-HP content in children was weakly but positively associated with the PAH content in the upper soil layer of the garden of their homes. However, this association was not found for the children from the other neighborhood built on coal-mine tailings and with similar PAH levels in soil. 25 refs., 4 tabs.

  3. Oil spill off the coast of Guimaras Island, Philippines: Distributions and changes of polycyclic aromatic hydrocarbons in shellfish.

    PubMed

    Uno, Seiichi; Kokushi, Emiko; Añasco, Nathaniel C; Iwai, Takenori; Ito, Kazuki; Koyama, Jiro

    2017-04-08

    The sinking of the Solar 1 tanker caused serious heavy oil pollution around Guimaras Island, Philippines. In the present study, variations of parent polycyclic aromatic hydrocarbons (PAHs) and alkylated PAHs (alkPAHs) in some shellfish were investigated around Guimaras Island and other small islands from 3months to 5years after the spill. The total PAHs and alkPAHs in shellfish were detected in high concentrations at 448 and 33,666ng/g dry weight, respectively, in November 2006. The concentrations of alkPAHs gradually decreased, while the parent PAHs in shellfish degraded more slowly than the alkPAHs, which was likely due to the persistent characteristics of PAHs. The risks based on European Union regulations were insignificant in 2008, but total PAHs in shellfish were still over 8 times higher at the investigated sites in November 2011 than that before the oil spill. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Use of the semipermeable membrane device (SPMD) to sample polycyclic aromatic hydrocarbon pollution in a lotic system

    USGS Publications Warehouse

    Lebo, Jon A.; Zajicek, James L.; Orazio, Carl E.; Petty, Jimmie D.; Huckins, James; Douglas, Ernest H.

    1996-01-01

    Relative concentrations of aqueous polycyclic aromatic hydrocarbons (PAH) were investigated in an urban creek. Samples were obtained at five sites within a 600-m segment of the creek that is critical habitat for an endangered species of fish. The sampling technique entailed immersion of semipermeable membrane devices (SPMDs) in the water for intervals as long as 64 d. SPMDs are passive, in situ, integrative samplers of bioavailable (truly dissolved) PAH and other hydrophobic organic contaminants. Two point sources of PAH to the 600-m segment of the creek were differentiated. Aqueous concentrations were found to wane dramatically over the relatively short section of the creek between the point sources. All samples were almost devoid of alkyl-substituted PAH, indicating that the ultimate sources were probably of pyrogenic nature.

  5. Ab initio calculation of through-space magnetic shielding of linear polycyclic aromatic hydrocarbons (acenes): extent of aromaticity.

    PubMed

    Martin, Ned H; Caldwell, Brian W; Carlson, Katie P; Teague, Matthew R

    2009-02-01

    GIAO-HF within Gaussian 03 was employed to compute the NMR isotropic shielding values of a diatomic hydrogen probe above a series of acenes (linear polycyclic aromatic hydrocarbons). Subtraction of the isotropic shielding of diatomic hydrogen by itself allowed the determination of computed through-space proton NMR shielding increment surfaces for these systems. Shielding was observed above the center of each aromatic ring, but the magnitude of calculated shielding above each ring center depends on the number of fused benzenoid rings. The computed shielding increments above each ring center were correlated to other measures of extent of aromaticity, including geometric, energetic, and magnetic measurements.

  6. 40 CFR 721.3845 - Alkyl substituted aromatic glycidyl ether (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... as alkyl substituted aromatic glycidyl ether (PMN P-97-661) is subject to reporting under this.... Requirements as specified in § 721.80(q). (iv) Release to water. Requirements as specified in § 721.90 (a)(1... in § 721.125 (a), (b), (c),(d),(e), (f), (g), (h),(i), and (k) are applicable to manufacturers...

  7. Fusing porphyrins with polycyclic aromatic hydrocarbons and heterocycles for optoelectronic applications

    DOEpatents

    Thompson, Mark E.; Diev, Viacheslav; Hanson, Kenneth; Forrest, Stephen R.

    2015-08-18

    A compound that can be used as a donor material in organic photovoltaic devices comprising a non-activated porphyrin fused with one or more non-activated polycyclic aromatic rings or one or more non-activated heterocyclic rings can be obtained by a thermal fusion process. The compounds can include structures of Formula I: ##STR00001## By heating the reaction mixture of non-activated porphyrins with non-activated polycyclic aromatic rings or heterocyclic rings to a fusion temperature and holding for a predetermined time, fusion of one or more polycyclic rings or heterocyclic rings to the non-activated porphyrin core in meso,.beta. fashion is achieved resulting in hybrid structures containing a distorted porphyrin ring with annulated aromatic rings. The porphyrin core can be olygoporphyrins.

  8. Risk assessment of occupational exposure to polycyclic aromatic hydrocarbons by means of urinary1-hydroxypyrene.

    PubMed

    Maina, Giovanni; Manzari, Marco; Palmas, Antonio; Passini, Valter; Filon, Francesca Larese

    2007-02-01

    Polycyclic aromatic hydrocarbons have mutagenic and carcinogenic properties and some of them are classified as probable or possible human carcinogens. Aim of this study was to evaluate the genotoxic risk in workers exposed to diesel exaust. Environmental and biological monitoring exposure to polycyclic aromatic hydrocarbons was carried out on fifty-two workers exposed to diesel exhaust. Urinary 1-hydroxypyrene was employed as a biomarker of internal dose. Significant urinary 1-hydroxypyrene differences between smokers and non-smokers were found. Twenty per cent of urinary 1-hydroxypyrene values exceeded benchmark level for genotoxic effect, while the results of environmental monitoring excluded the existence of exposure to polycyclic aromatic hydrocarbons. In the absence of greater knowledge about the relationship between urinary 1-hydroxypyrene and genotoxic effects under the conditions of very low exposure, extreme caution is recommended when this biomarker of internal dose is employed as an indicator of genotoxic risk.

  9. Absorption of nitro-polycyclic aromatic hydrocarbons by biomembrane models: effect of the medium lipophilicity.

    PubMed

    Castelli, Francesco; Micieli, Dorotea; Ottimo, Sara; Minniti, Zelica; Sarpietro, Maria Grazia; Librando, Vito

    2008-10-01

    To demonstrate the relationship between the structure of nitro-polycyclic aromatic hydrocarbons and their effect on biomembranes, we have investigated the influence of three structurally different nitro-polycyclic aromatic hydrocarbons, 2-nitrofluorene, 2,7-dinitrofluorene and 3-nitrofluoranthene, on the thermotropic behavior of dimyristoylphosphatidylcholine multilamellar vesicles, used as biomembrane models, by means of differential scanning calorimetry. The obtained results indicate that the studied nitro-polycyclic aromatic hydrocarbons affected the thermotropic behavior of multilamellar vesicles to various extents, modifying the pretransition and the main phase transition peaks and shifting them to lower temperatures. The effect of the aqueous and lipophilic medium on the absorption process of these compounds by the biomembrane models has been also investigated revealing that the process is hindered by the aqueous medium but strongly allowed by the lipophilic medium.

  10. Polycyclic aromatic hydrocarbons profiles of spent drilling fluids deposited at Emu-Uno, Delta State, Nigeria.

    PubMed

    Iwegbue, Chukwujindu M A

    2011-10-01

    The concentrations and profiles of polycyclic aromatic hydrocarbons were determined in spent drilling fluid deposited at Emu-Uno, Delta State of Nigeria. The total concentrations of polycyclic aromatic hydrocarbons in the spent drilling fluid deposits ranged between 40 and 770 μg kg(-1). The PAHs profile were predominantly 2- and 3-rings with acenaphthalene, phenanthrene, fluorene being the predominant PAHs. The prevalence of 2- and 3-rings PAHs in the spent drilling fluid deposits indicate contamination of the drilling fluids with crude oil during drilling. Incorporation of spent drilling fluids into the soil has serious implication for soil, surface water and groundwater quality.

  11. Remediation of polycyclic aromatic hydrocarbons. (Latest citations from Pollution abstracts). Published Search

    SciTech Connect

    1995-10-01

    The bibliography contains citations concerning the removal of polycyclic aromatic hydrocarbons from contaminated soil or water. The chemical or biological processes that destroy these contaminants or reduce their toxicity are discussed. Techniques include treatments used in above-ground reactors or in situ detoxification of contaminated sites. The citations examine the relationship between the chemical structure of polycyclic aromatic hydrocarbons and rate of decomposition; selection of the most effective microorganisms for biological degradation; and factors which can accelerate or inhibit degradation.(Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  12. Remediation of polycyclic aromatic hydrocarbons. (Latest citations from Pollution Abstracts). Published Search

    SciTech Connect

    1995-03-01

    The bibliography contains citations concerning the removal of polycyclic aromatic hydrocarbons from contaminated soil or water. The chemical or biological processes that destroy these contaminants or reduce their toxicity are discussed. Techniques include treatments used in above-ground reactors or in situ detoxification of contaminated sites. The citations examine the relationship between the chemical structure of polycyclic aromatic hydrocarbons and rate of decomposition; selection of the most effective microorganisms for biological degradation; and factors which can accelerate or inhibit degradation. (Contains a minimum of 108 citations and includes a subject term index and title list.)

  13. Remediation of polycyclic aromatic hydrocarbons. (Latest citations from Pollution Abstracts). Published Search

    SciTech Connect

    1996-12-01

    The bibliography contains citations concerning the removal of polycyclic aromatic hydrocarbons from contaminated soil or water. The chemical or biological processes that destroy these contaminants or reduce their toxicity are discussed. Techniques include treatments used in above-ground reactors or in situ detoxification of contaminated sites. The citations examine the relationship between the chemical structure of polycyclic aromatic hydrocarbons and rate of decomposition; selection of the most effective microorganisms for biological degradation; and factors which can accelerate or inhibit degradation.(Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  14. Remediation of polycyclic aromatic hydrocarbons. (Ltest citations from Pollution abstracts). Published Search

    SciTech Connect

    Not Available

    1994-07-01

    The bibliography contains citations concerning the removal of polycyclic aromatic hydrocarbons from contaminated soil or water. The chemical or biological processes that destroy these contaminants or reduce their toxicity are discussed. Techniques include treatments used in above-ground reactors or in situ detoxification of contaminated sites. The citations examine the relationship between the chemical structure of polycyclic aromatic hydrocarbons and rate of decomposition; selection of the most effective microorganisms for biological degradation; and factors which can accelerate or inhibit degradation. (Contains a minimum of 82 citations and includes a subject term index and title list.)

  15. Remediation of polycyclic aromatic hydrocarbons. (Latest citations from Pollution abstracts). Published Search

    SciTech Connect

    1997-12-01

    The bibliography contains citations concerning the removal of polycyclic aromatic hydrocarbons from contaminated soil or water. The chemical or biological processes that destroy these contaminants or reduce their toxicity are discussed. Techniques include treatments used in above-ground reactors or in situ detoxification of contaminated sites. The citations examine the relationship between the chemical structure of polycyclic aromatic hydrocarbons and rate of decomposition; selection of the most effective microorganisms for biological degradation; and factors which can accelerate or inhibit degradation.(Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  16. Determination of polycyclic aromatic hydrocarbons in dry tea

    PubMed Central

    ADISA, AFOLABI; JIMENEZ, ANGELICA; WOODHAM, CARA; ANTHONY, KEVIN; NGUYEN, THAO; SALEH, MAHMOUD A.

    2016-01-01

    Twenty-eight different tea samples sold in the United States were evaluated using high-performance liquid chromatography (HPLC) with fluorescence detection (FLD) for their contamination with polycyclic aromatic hydrocarbons (PAHs). Many PAHs exhibit carcinogenic, mutagenic, and teratogenic properties and have been related to several kinds of cancer in man and experimental animals. The presence of PAHs in environmental samples such as water, sediments, and particulate air has been extensively studied, but food samples have received little attention. Eighteen PAHs congeners were analyzed, with percentage recovery higher than 85%. Contamination expressed as the sum of the 18 analyzed PAHs was between 101 and 1337 μg/kg on dry mass and the average contents in all of the 28 examined samples was 300 μg/kg on dry mass. Seven of the congeners were found in all samples with wide ranges of concentrations as follows: fluorene (7–48 μg/kg), anthracene (1–31 μg/kg), pyrene (1–970 μg/kg), benzo(a)anthracene (1–18 μg/kg) chrysene (17–365 μg/kg), benzo(a)pyrene (1–29 μg/kg), and indeno(1,2,3-cd)pyrene (4–119 μg/kg). The two most toxic congeners benzo(a)pyrene and dibenzo(a,h)anthracene were found at high concentrations only in Earl Grey Twinnings, Earl Grey Harney& Sons Fine Teas, and Chai Ultra Spice Black Tea Twinnings. Six PAH congeners are considered as suspected carcinogens (U.S.EPA), formed the basis of the estimation of the toxic equivalent (TEQ), Chai Ultra-Spice Black Tea Twinnings had the highest TEQ (110.9) followed by two grey tea samples, Earl Grey Harney & Sons Fine Tea (57.7) and Earl Grey Twinnings (54.5). Decaffeinated grey teas had the lowest TEQs, decaffeinated Earl Grey Bigelow (9.4) and Green Tea Honey Lemon Decaffeinated Lipton (9.6). PMID:26065515

  17. Bioremediation of Mixtures of High Molecular Weight Polycyclic Aromatic Hydrocarbons

    NASA Astrophysics Data System (ADS)

    Xu, H.; Wu, J.; Shi, X.; Sun, Y.

    2014-12-01

    Although bioremediation has been considered as one of the most promising means to remove polycyclic aromatic hydrocarbons (PAHs) from polluted environments, the efficacy of PAHs bioremediation still remains challenged, especially for high molecular weight PAHs (HMW PAHs) and their mixtures. This study was focused on (a) isolation and characterization of pure strain and mixed microbial communities able to degrade HMW PAHs and (b) further evaluation of the ability of the isolated microbes to degrade HMW PAHs mixtures in the absence and presence of indigenous flora. Fluoranthene, benzo[b]fluoranthene and pyrene were selected as the representative HMW PAHs in this study. A pure bacterial strain, identified as Herbaspirillum chlorophenolicum FA1, was isolated from activated sludge. A mixed bacterial community designated as consortium-4 was isolated from petroleum contaminated soils, containing Pseudomonas sp. FbP1、Enterobacter sp. FbP2、Hydrogenophaga sp. FbP3 and Luteolibacter pohnpeiensis. FbP4. To our knowledge, this is the first study to demonstrate that bacterial strains of Herbaspirillum chlorophenolicum FA1 and Luteolibacter pohnpeiensis. FbP4 can also degrade fluoranthene, benzo[b]fluoranthene and pyrene. Experiment results showed that both strain FA1 and consortium-4 could degrade fluoranthene, benzo[b]fluoranthene and pyrene within a wide range of temperature, pH and initial PAHs concentration. Degradation of HMW PAHs mixtures (binary and ternary) demonstrated the interactive effects that can alter the rate and extent of biodegradation within a mixture. The presence of indigenous flora was found to either increase or decrease the degradation of HMW PAHs, suggesting possible synergistic or competition effects. Biodegradation kinetics of HMW PAHs for sole substrates, binary and ternary systems was evaluated, with the purpose to better characterize and compare the biodegradation process of individual HMW PAH and mixtures of HMW PAHs. Results of this study

  18. An Emission Inventory of Polycyclic Aromatic Hydrocarbons in China

    NASA Astrophysics Data System (ADS)

    Mu, Xilong; Zhu, Xianlei; Wang, Xuesong

    2015-04-01

    Polycyclic Aromatic Hydrocarbons (PAHs) are among the most dangerous compounds due to their high carcinogenic and mutagenic character. Emission inventory provides the primary data to account for the sources of ambient PAHs and server as a necessary database for effective PAHs pollution control. China is experiencing fast economic growth and large energy consumption, which might result in a large amount of PAHs anthropogenic emissions. Therefore, based on the previous studies and combined recently field emission measurements as well as socio-economic activity data, the development of a nationwide PAHs emission inventory is needed. In this work, the emission inventory of 16 PAHs listed as U.S. Environmental Protection Agency priority pollutants in China in the year 2012 is compiled. The emission amounts of PAHs were estimated as annual rates of emission-related activities multiplied by respective emission factors. The activities such as fuel consumption, including fossil fuel and biofuel, and socio-economic statistics were obtained from yearbook released by Chinese central government and/or provincial governments, as well as related industry reports. Emission factors were derived from the related literature. Recently reported emission factors from local measurements were used. The total emissions of PAHs were 120611 ton in 2012. In China, PAHs were emitted predominantly from domestic combustion of coal and biofuel, coking industry and motor vehicles, accounting for 72% of the total amount. PAHs emission profiles were significantly different between China and the other countries. The emission profile in China featured a relatively higher portion of high molecular weight species with carcinogenic potential due to large contributions of domestic combustion and coking industry. Domestic combustion of straw, coal and firewood emitted 19464 ton, 8831 ton, and 5062 ton of PAHs, respectively, which were much higher than those in other countries. Emission per capita showed

  19. Mitochondrial DNA Copy Number and Exposure to Polycyclic Aromatic Hydrocarbons

    PubMed Central

    Pavanello, Sofia; Dioni, Laura; Hoxha, Mirjam; Fedeli, Ugo; Mielzynska-Švach, Danuta; Baccarelli, Andrea A.

    2013-01-01

    Background Increased mitochondrial DNA copy number (mtDNAcn) is a biological response to mtDNA damage and dysfunction predictive of lung cancer risk. Polycyclic aromatic hydrocarbons (PAHs) are established lung carcinogens and may cause mitochondrial toxicity. Whether PAH exposure and PAH-related nuclear DNA (nDNA) genotoxic effects are linked with increased mtDNAcn has never been evaluated. Methods We investigated the effect of chronic exposure to PAHs on mtDNAcn in peripheral blood lymphocytes (PBLs) of 46 Polish male non-current smoking cokeoven workers and 44 matched controls, who were part of a group of 94 study individuals examined in our previous work. Subjects PAH exposure and genetic alterations were characterized through measures of internal dose (urinary 1-pyrenol), target dose [anti-benzo[a]pyrene diolepoxide (anti-BPDE)-DNA adduct], genetic instability (micronuclei, MN and telomere length [TL]) and DNA methylation [p53 promoter] in PBLs. mtDNAcn (MT/S) was measured using a validated real-time PCR method. Results Workers with PAH exposure above the median value (>3 µmol 1-pyrenol/mol creatinine) showed higher mtDNAcn [geometric means (GM) of 1.06 (unadjusted) and 1.07 (age-adjusted)] compared to controls [GM 0.89 (unadjusted); 0.89 (age-adjusted)] (p=0.029 and 0.016), as well as higher levels of genetic and chromosomal [i.e. anti-BPDE-DNA adducts (p<0.001), MN (p<0.001) and TL (p=0.053)] and epigenetic [i.e., p53 gene-specific promoter methylation (p<0.001)] alterations in the nDNA. In the whole study population, unadjusted and age-adjusted mtDNAcn was positively correlated with 1-pyrenol (p=0.043 and 0.032) and anti-BPDE-DNA adducts (p=0.046 and 0.049). Conclusions PAH exposure and PAH-related nDNA genotoxicity are associated with increased mtDNAcn. Impact The present study is suggestive of potential roles of mtDNAcn in PAH-induced carcinogenesis. PMID:23885040

  20. Radiation and chemical studies of carcinogens, polycyclic aromatic hydrocarbons

    SciTech Connect

    Chen, Chiachieh.

    1989-01-01

    Radiation and polycyclic aromatic hydrocarbons (PAH's) are environmental pollutants. 3MC effectively neutralized the lethality of C3H mouse 10T1/2 cells resulting from B(a)P or DMBA. PAH binding to macromolecules increased linearly with exposure, but DNA-adducts saturated with exposure. 3MC or {alpha}NF appreciably reduced the formation of DNA adducts due to B(a)P or DMBA. The reductions in DNA-adduct formation did not result from a reduction in the induction of AHH. By using DNA adducts as chemical dose, and plotting the DMBA survival curve as a function of DMBA-DNA adducts, the curve was an exponential curve. A similar application with B(a)P-DNA adduct showed the survival curve as a shoulder followed by an exponential region. When 10T1/2 cells were treated with X-radiation and a PAH, the nontoxic compounds and B(a)P did not show any significant effect on X-ray survival curve. However, the damage due to DMBA was found to be additive to X-ray damage. The latter property of DMBA was lost when cells were cotreated with 3MC and DMBA presumably because damage to DNA due to DMBA alone was suppressed. Thus, the combined action is complex. DMBA produced damage in 10T1/2 cells that added to radiation damage. Although a nontoxic PAH could neutralize the effect of a toxic PAH, the former were not able to mitigate the lethal effects of radiation. Operationally, the latter results suggested that a nontoxic PAH could cancel out the effect of a toxic one because it inhibited the formation of the DNA damage with which radiation damage could interact rather than because the nontoxic PAH removed the radiation damage with which the PAH could interact. It showed that at least 4 hours were required for DMBA to affect the sublethal radiation damage repair, a period long enough for a large fraction of the latter damage to have been lost.

  1. The Origins of Polycyclic Aromatic Hydrocarbons: Are They Everywhere?

    NASA Technical Reports Server (NTRS)

    Allamandola, L. J.; Morrison, David (Technical Monitor)

    1994-01-01

    During the past 15 years considerable progress in observational techniques has been achieved in the middle-infrared region (5000-500 per centimeter, 2-20 micron), the region where most diagnostic molecular vibrations occur. Spectra of many different astronomical infrared sources, some deeply embedded in dark molecular clouds and others at their edges, are now available. These spectra provide a powerful probe, not only for the identification of interstellar molecules in both the gas and solid phases, but also of the physical and chemical conditions which prevail in these two very different domains. The two lectures will focus on the evidence that polycyclic aromatic hydrocarbons (PAHs) are an important, ubiquitous and abundant interstellar species. PAHs are. extremely stable species which can range in size from a few angstroms across to several hundred angstroms (PAHs are also the building blocks of amorphous carbon particles). This identification rests on the suggestive agreement between the laboratory spectra of PAHs with a set of IR emission bands which emanate from many different sources where ultraviolet starlight impinges on a "dusty" region. The picture is that individual PAHs are first pumped into highly vibrationally excited states and relax by fluorescence at their fundamental vibrational frequencies. That PAHs are a ubiquitous interstellar component has serious ramifications in other spectral regions as well, including the strong extinction in the ultraviolet, and the classic visible diffuse interstellar bands discovered more than 50 years ago (but unexplained to this day) The first part of the course will focus on the interpretation of astronomical spectra. The second lecture will start by showing how recent laboratory data on PAHs taken under realistic interstellar conditions has con borated the PAH hypothesis and led to great insight into the conditions in the PAH containing regions. This lecture will end by reviewing the ever-increasing evidence for

  2. Ecotoxicity of a polycyclic aromatic hydrocarbon (PAH)-contaminated soil.

    PubMed

    Eom, I C; Rast, C; Veber, A M; Vasseur, P

    2007-06-01

    Soil samples from a former cokery site polluted with polycyclic aromatic hydrocarbons (PAHs) were assessed for their toxicity to terrestrial and aquatic organisms and for their mutagenicity. The total concentration of the 16 PAHs listed as priority pollutants by the US Environmental Protection Agency (US-EPA) was 2634+/-241 mg/kgdw in soil samples. The toxicity of water-extractable pollutants from the contaminated soil samples was evaluated using acute (Vibrio fischeri; Microtox test, Daphnia magna) and chronic (Pseudokirchneriella subcapitata, Ceriodaphnia dubia) bioassays and the EC values were expressed as percentage water extract in the test media (v/v). Algal growth (EC50-3d=2.4+/-0.2% of the water extracts) and reproduction of C. dubia (EC50-7d=4.3+/-0.6%) were the most severely affected, compared to bacterial luminescence (EC50-30 min=12+/-3%) and daphnid viability (EC50-48 h=30+/-3%). The Ames and Mutatox tests indicated mutagenicity of water extracts, while no response was found with the umu test. The toxicity of the soil samples was assessed on the survival and reproduction of earthworms (Eisenia fetida) and collembolae (Folsomia candida), and on the germination and growth of higher plants (Lactuca sativa L.: lettuce and Brassica chinensis J.: Chinese cabbage). The EC50 values were expressed as percentage contaminated soil in ISO soil test medium (weight per weight-w/w) and indicated severe effects on reproduction of the collembola F. candida (EC50-28 d=5.7%) and the earthworm E. fetida (EC50-28 d=18% and EC50-56 d=8%, based on cocoon and juvenile production, respectively). Survival of collembolae was already affected at a low concentration of the contaminated soil (EC50-28 d=11%). The viability of juvenile earthworms was inhibited at much lower concentrations of the cokery soil (EC50-14 d=28%) than the viability of adults (EC50-14 d=74%). Only plant growth was inhibited (EC50-17d=26%) while germination was not. Chemical analyses of water extracts allowed

  3. The environmental fate of polycyclic aromatic hydrocarbons associated with particles

    NASA Astrophysics Data System (ADS)

    Kim, Daekyun

    This study focused on the transport and distribution in the environment, the phototransformation, and the source identification of particle-associated polycyclic aromatic hydrocarbons (PAHs). To investigate the main inputs and sources of PAHs, particulate, dissolved, and colloid-bound PAHs in stream and precipitation samples collected along an urban tributary were monitored between October 2004 and March 2005. Particulate matter carried by stormwater runoff was the major source of PAHs in surface water in the early rainy season. Indirect deposition of PAHs into surface water is likely a more significant input pathway for total PAHs than direct dry or wet deposition during the wet season. Selected PAH ratios indicate that observed PAHs in rainwater came from pyrogenic sources and those in surface water had more complicated and variable origins. To examine possible changes in the PAH profiles caused by environmental aging, soot particles were exposed to simulated sunlight and disappearance rates of PAHs were determined. An obvious two-phase disappearance was observed for naphthalene, acenaphthylene, acenaphthene, and fluorene, while phenanthrene and anthracene exhibited this behavior for all but the highest soot loading. The first phase loss occurred within 3-10 hours is 5-40 times faster than the second phase loss. Only single mode of disappearance, however, was observed for the higher molecular weight PAHs with 4-6 rings. Sources of PAHs from surface waters and sediments should be determined by considering the potential influence of aging on any diagnostic method. Due to differences in disappearance rates of individual PAHs, prolonged exposure to sunlight could change the interpretation of characteristic PAH ratios. The apparent disappearance rates of PAHs on soot are governed by photodegradation and diffusion kinetics. The effective diffusion coefficients, the photodegradation rate constants, and the light penetration depth for fluorene, phenanthrene, and

  4. New biomarkers of occupational exposure to polycyclic aromatic hydrocarbons.

    PubMed

    Seidel, Albrecht; Spickenheuer, Anne; Straif, Kurt; Rihs, Hans-Peter; Marczynski, Boleslaw; Scherenberg, Michael; Dettbarn, Gerhard; Angerer, Jürgen; Wilhelm, Michael; Brüning, Thomas; Jacob, Jürgen; Pesch, Beate

    2008-01-01

    Polycyclic aromatic hydrocarbons (PAH) are metabolized in a complex manner. Although biological activity is associated with diol-epoxide formation, phenolic metabolites have predominantly been used in human biomonitoring. In this study monohydroxylated and new metabolites were characterized as biomarkers for occupational PAH exposure. In 97 male workers, personal exposure to 16 airborne PAH compounds was measured during shift. In postshift urine, 1-hydroxypyrene and 1,6- and 1,8-dihydroxypyrene (1-OHP, DiOHP) were determined as metabolites of pyrene (P), and the sum of 1-, 2-, 3-, 4-, and 9-hydroxyphenanthrenes (OHPHE), and PHE-dihydrodiols (PHED) as metabolites of phenanthrene (PHE). The referent group comprised 21 nonsmoking construction workers. Median (interquartile range) shift concentrations of airborne P and PHE were 1.46 (0.62-4.05 microg/m(3)) and 10.9 (3.69-23.77 microg/m(3)), respectively. The corresponding parameters were 3.86 (2.08-7.44) microg/g creatinine (crn) for 1-OHP, 0.66 (0.17-1.65) microg/g crn for DiOHP, 11.44 (5.21-34.76) microg/g crn for OHPHE, and 12.28 (3.3-97.76) microg/g crn for PHED in PAH-exposed workers. The median levels of 1-OHP and OHPHE were 0.09 (0.08-0.17 microg/m(3)) and 0.59 (0.45-1.39 microg/m(3)), respectively, in the referents. PHE correlated significantly with OHPHE and PHED, and P with 1-OHP but not with DiOHP. Under a doubling of PHE, OHPHE increased by a factor of 1.56 and PHED by 1.57. With a doubling of P, 1-OHP rose by 1.31 and DiOHP by 1.27. P is predominantly metabolized into 1-OHP, whereas PHE is metabolized equally into OHPHE and PHED. Thus metabolites of PHE were found as reliable biomarkers for PAH exposure.

  5. The Origins of Polycyclic Aromatic Hydrocarbons: Are They Everywhere?

    NASA Technical Reports Server (NTRS)

    Allamandola, L. J.; Morrison, David (Technical Monitor)

    1994-01-01

    During the past 15 years considerable progress in observational techniques has been achieved in the middle-infrared region (5000-500 per centimeter, 2-20 micron), the region where most diagnostic molecular vibrations occur. Spectra of many different astronomical infrared sources, some deeply embedded in dark molecular clouds and others at their edges, are now available. These spectra provide a powerful probe, not only for the identification of interstellar molecules in both the gas and solid phases, but also of the physical and chemical conditions which prevail in these two very different domains. The two lectures will focus on the evidence that polycyclic aromatic hydrocarbons (PAHs) are an important, ubiquitous and abundant interstellar species. PAHs are. extremely stable species which can range in size from a few angstroms across to several hundred angstroms (PAHs are also the building blocks of amorphous carbon particles). This identification rests on the suggestive agreement between the laboratory spectra of PAHs with a set of IR emission bands which emanate from many different sources where ultraviolet starlight impinges on a "dusty" region. The picture is that individual PAHs are first pumped into highly vibrationally excited states and relax by fluorescence at their fundamental vibrational frequencies. That PAHs are a ubiquitous interstellar component has serious ramifications in other spectral regions as well, including the strong extinction in the ultraviolet, and the classic visible diffuse interstellar bands discovered more than 50 years ago (but unexplained to this day) The first part of the course will focus on the interpretation of astronomical spectra. The second lecture will start by showing how recent laboratory data on PAHs taken under realistic interstellar conditions has con borated the PAH hypothesis and led to great insight into the conditions in the PAH containing regions. This lecture will end by reviewing the ever-increasing evidence for

  6. Sorption of polycyclic aromatic hydrocarbons by aquia aquifer materials

    SciTech Connect

    Ostazeski, S.A.

    1992-01-01

    The sorption of three polycyclic aromatic hydrocarbons (PAHs) by Aquia Aquifer materials was investigated. Laboratory studies were conducted to generate equilibrium isotherm data using batch shake techniques. Six aquifer materials, with f[sub oc] values ranging from 0.0002 to 0.0089 were used. The influence of the solution phase conditions of pH, ionic strength, and cosolvent on sorption was investigated. Sorption isotherms could be described by the linear form of the Freundlich relationship. The sorption partition coefficients (K[sub d]) for sorption from aqueous solution were greater than predicted by an f[sub oc] basis alone. The K[sub d]s obtained for pyrene and phenanthrene were significantly related to f[sub oc] SA[sup [minus]1] (SA = specific surface area). This was not the case K[sub d] values obtained for naphthalene sorption. The solution phase conditions of pH and ionic strength were found to have a significant effect on the sorption of PAHs by aquifer materials. The effect of solution phase pH on the sorption of individual PAHs by aquifer materials was seen to be a concave up curve with a minimum about a pH of 7. The data obtained from ionic strength experiments indicated maximum sorption occurs at NaCl molar concentration of zero. The data is not well represented by a modified Setchenow relationship, but suggest that the sorptive capacity of the aquifer material may be modified by changes in the sorbent organic carbon. The isotherms generated for sorption of PAHs from methanol/water solution were found to be linear. The (K[sub d]) values were consistent with predictions made on the basis of sorbent f[sub oc] at low volume fractions of methanol. For all solutes and sorbents studied deviations from the predicted occurred as the volume fraction of methanol increased. These results suggest conformational changes in the sorbent f[sub oc] occur with varying solution phase conditions.

  7. Fate of polycyclic aromatic hydrocarbons during composting of oily sludge.

    PubMed

    Kriipsalu, M; Marques, M; Hogland, W; Nammari, D R

    2008-01-01

    In order to assess the effectiveness of aerobic degradation with emphasis on the 16 U.S. EPA priority polycyclic aromatic hydrocarbons (PAH), oily sludge generated by a dissolved air flotation flocculation unit of a wastewater treatment plant in a petroleum refinery was amended with remediated oil-contaminated soil and non-mature garden waste compost 40:40:20 (wet weight) respectively. About 21 t of the mixture with a top-layer formed by 30 cm of remediated soil was treated in a 28 m3 air-forced reactor. The PAH concentration was monitored for 370 days. In the top-layer, a reduction of 88 % of the total extractable PAH was measured at day 62 and a final reduction of 93% at day 370. In the mixture, a reduction of 72% in total PAH was measured at day 62, followed by fluctuation in concentration with a final measured reduction of 53% at day 370. The analysis of individual PAH in the mixture suggested that volatilization and biodegradation are the main mechanisms responsible for the reduction of 2 ring PAH and 3-4 ring PAH, respectively. Fluctuation of 5-6 ring PAH concentrations with increase observed at the end of the period might result from a combination of the following: (i) sequestration of large PAH in the organic matrix (reducing bioavailability, biodegradability and eventually, extractability) and desorption as composting progresses; (ii) heterogeneous distribution of the stable large PAH in the mixture, thus affecting sampling. It was concluded that one-time composting in static-aerated biopiles with organic amendments as the sole strategy to treat oily sludge is very effective in reducing the content of 2-4 ring PAH, but it is not effective in reducing the content of 5-6 ring PAHs, even after a relatively long time span (370 d). The concentrations measured in the remediated soil that formed the top layer after 62 days of composting suggests that further relevant reduction of residual PAH (89% of total PAH and 69% of 5-6 ring PAH) can be obtained if the

  8. Polycyclic aromatic hydrocarbons in US and Swedish smokeless tobacco products

    PubMed Central

    2013-01-01

    Background Debate about the health implications of using smokeless tobacco products (STPs) has prompted considerable interest in characterising their levels of toxic and carcinogenic components. In the present study seventy smokeless tobacco products from the US and Sweden, categorized as chewing tobacco, dry and moist snuff, hard and soft pellets, plug, and loose and portion snus, were analysed for twenty one polycyclic aromatic hydrocarbons (PAHs). The tested brands represented 80-90% of the 2008 market share for the major STP categories in these two countries. Results There were significant differences in the total and individual PAH concentrations in the different styles of product. Substantially higher levels of total PAHs (10–60 fold) were found in moist and dry snuff and soft pellets than in the other smokeless tobacco styles. The individual PAH concentrations followed the same patterns as total PAHs except for naphthalene, for which the highest concentrations were found in snus and moist snuff. Good correlations were obtained between benzo[a]pyrene (B[a]P) and all the other PAHs except naphthalene, 1-methylnaphthalene and 2-methylnaphthalene, providing evidence for the first time that it can be used as a good marker for PAHs in STPs. Results were generally in good agreement with two previous studies of PAHs in STPs, except for naphthalene for which significantly lower concentrations were found than previously reported. Analysis of the ratios of different PAHs confirmed that the use of fire-cured tobaccos in the snuffs and soft pellet were the major source of PAHs in these product styles, and provided, for the first time, some indications as to the source of PAHs in the other STP styles, including petrogenic and other combustion sources. Conclusions This study confirms the presence of PAHs in STPs, and identifies substantial differences between the levels in different STP categories. Since previous studies of naphthalene concentrations in STPs differed so

  9. Development of a flow-injection fluorescence method for estimation of total polycyclic aromatic compounds in asphalt fumes.

    PubMed

    Neumeister, Charles E; Olsen, Larry D; Dollberg, Donald D

    2003-01-01

    Traditionally, measurements of specific polycyclic aromatic compounds (PACs) have been attempted as an estimate of asphalt fume exposure. However, asphalt fumes contain numerous alkyl substituted PACs, including PACs containing heteroatoms of nitrogen, oxygen, and sulfur. Many of these compounds coelute precluding the resolution of the individual compounds resulting in ambiguous data. Moreover, many researchers believe that some observed health hazards are associated with PACs overall and not just a few select PACs. Therefore, NIOSH method 5800 was developed to evaluate total PACs as a chemical class in asphalt fumes. Asphalt fume samples were collected on a poly(tetrafluoroethylene) filter backed by an XAD-2 sorbent tube. The samples were extracted with hexane; then, a cyano-solid-phase-extraction column was used to remove the polar compounds while the aliphatic and aromatic compounds were eluted with hexane. An equal volume of dimethyl sulfoxide (DMSO) was added to the hexane extract, causing the aromatic compounds to partition into the DMSO, thus isolating the PACs. The PACs were then analyzed for fluorescence using a flow-injection method with two fluorescence detectors. Wavelength settings for the first detector (254-nm excitation, 370-nm emission) emphasized the 2- to 4-ring PACs that may cause eye and respiratory tract irritation. Wavelength settings of the second detector (254-nm excitation, 400-nm emission) emphasized the 4- and higher-ring PACs that are often mutagenic and possibly carcinogenic.

  10. Oil droplet fouling and differential toxicokinetics of polycyclic aromatic hydrocarbons in embryos of Atlantic haddock and cod

    PubMed Central

    Sørhus, Elin; Nordtug, Trond; Incardona, John P.; Linbo, Tiffany L.; Giovanetti, Laura; Karlsen, Ørjan; Meier, Sonnich

    2017-01-01

    The impact of crude oil pollution on early life stages (ELS) of fish, including larvae and embryos, has received considerable attention in recent years. Of the organic components present in crude oil, polycyclic aromatic hydrocarbons (PAHs) are considered the main class of compounds responsible for toxic effects in marine organisms. Although evidence suggests that they are more toxic, alkylated PAHs remain much less studied than their unsubstituted congeners. Recently, it was established that embryos of Atlantic haddock (Melanogrammus aeglefinus) are particularly sensitive to dispersed crude oil, and it was hypothesized that this was caused by direct interaction with crude oil droplets, which adhered to the chorion of exposed embryos. Such a phenomenon would increase the potential for uptake of less water-soluble compounds, including alkylated PAHs. In the current study, we compared the uptake of parent and alkylated PAHs in Atlantic cod (Gadus morhua) and haddock embryos exposed to dispersed crude oil at a range of environmentally relevant concentrations (10–600 μg oil/liter seawater). Although the species are biologically very similar, the cod chorion does not become fouled with oil droplets, even when the two species are exposed to dispersions of crude oil droplets under similar conditions. A close correlation between the degree of fouling and toxicological response (heart defects, craniofacial malformation) was observed. Oil droplet fouling in haddock led to both quantitative and qualitative differences in PAH uptake. Finally, kinetic data on a large suite of PAHs showed differential elimination, suggesting differential metabolism of unsubstituted versus alkylated compounds. PMID:28678887

  11. Environmental Behaviors and Toxicities of Polycyclic Aromatic Hydrocarbons and Nitropolycyclic Aromatic Hydrocarbons.

    PubMed

    Hayakawa, Kazuichi

    2016-01-01

    Airborne particulate matter (PM) has been collected at four cities in Japan starting in the late 1990s, at five or more major cities in China, Korea and Russia starting in 2001 and at the Noto Peninsula starting in 2004. Nine polycyclic aromatic hydrocarbons (PAHs) and eleven nitropolycyclic aromatic hydrocarbons (NPAHs) were determined by HPLC with fluorescence and chemiluminescence detections, respectively. Annual concentrations of PAHs and NPAHs were in the order, China>Russia≫Korea=Japan, with seasonal change (winter>summer). During the observation period, concentrations of PAHs and NPAHs in Japanese cities significantly decreased but the increases in the PAH concentration were observed in Chinese and Russian cities. Concentrations of PAHs and NPAHs were higher in the Northern China than those in the Southern China. At the Noto peninsula, which is in the main path of winter northwest winds and a year-round jet stream that blow from the Asian continent to Japan, the concentrations were high in winter and low in summer every year. A cluster analysis and back trajectory analysis indicated that PAHs and NPAHs were long-range transported from Northeastern China, where coal burning systems such as coal-heating boilers are considered to be the major contributors of PAHs and NPAHs. A dramatic change in atmospheric concentrations of PAHs and NPAHs in East Asia suggests the rapid and large change of PM2.5 pollution in East Asia. Considering the adverse health effects of PM2.5, continuous monitoring of atmospheric PAHs and NPAHs is necessary in this area.

  12. Recent analytical methods for atmospheric polycyclic aromatic hydrocarbons and their derivatives.

    PubMed

    Hayakawa, Kazuichi; Tang, Ning; Toriba, Akira

    2017-01-01

    Polycyclic aromatic hydrocarbons (PAHs) and nitropolycyclic aromatic hydrocarbons (NPAHs) are ubiquitous environmental pollutants. Moreover, some oxidative metabolites of these pollutants, such as hydroxylated and epoxide PAHs, cause endocrine disruption or produce reactive oxygen species. These compounds have become a large concern from the viewpoint of particulate matter (PM2.5 ) pollution. This report deals with recent studies concerning analytical methods for PAHs, NPAHs and related compounds in atmospheric and biological samples.

  13. Polycyclic aromatic hydrocarbons in Australian coals. III. Structural elucidation by proton nuclear magnetic resonance spectroscopy

    SciTech Connect

    Chaffee, A.L.; Fookes, C.J.R.

    1988-01-01

    The molecular structures of a number of tetra- and pentacyclic aromatic hydrocarbons present in extracts of Victorian brown coal have been unambiguously established by /sup 1/H-NMR. The determined structures support the hypothesis that these polycyclic aromatic hydrocarbons (PAHs) are diagenetically derived from triterpenoid precursors based on the oleanane, ursane and lupane skeletons. The occurrence of diastereoisomerism in these PAHs has been revealed for the first time and the diastereomeric configurations of one pair of triaromatic compounds (XI and XII) defined.

  14. Polycyclic aromatic hydrocarbons in ocean sediments from the North Pacific to the Arctic Ocean.

    PubMed

    Ma, Yuxin; Halsall, Crispin J; Xie, Zhiyong; Koetke, Danijela; Mi, Wenying; Ebinghaus, Ralf; Gao, Guoping

    2017-08-01

    Eighteen polycyclic aromatic hydrocarbons (PAHs) were measured in surficial sediments along a marine transect from the North Pacific into the Arctic Ocean. The highest average Σ18PAHs concentrations were observed along the continental slope of the Canada Basin in the Arctic (68.3 ± 8.5 ng g(-1) dw), followed by sediments in the Chukchi Sea shelf (49.7 ± 21.2 ng g(-1) dw) and Bering Sea (39.5 ± 11.3 ng g(-1) dw), while the Bering Strait (16.8 ± 7.1 ng g(-1) dw) and Central Arctic Ocean sediments (13.1 ± 9.6 ng g(-1) dw) had relatively lower average concentrations. The use of principal components analysis with multiple linear regression (PCA/MLR) indicated that on average oil related or petrogenic sources contributed ∼42% of the measured PAHs in the sediments and marked by higher concentrations of two methylnaphthalenes over the non-alkylated parent PAH, naphthalene. Wood and coal combustion contributed ∼32%, and high temperature pyrogenic sources contributing ∼26%. Petrogenic sources, such as oil seeps, allochthonous coal and coastally eroded material such as terrigenous sediments particularly affected the Chukchi Sea shelf and slope of the Canada Basin, while biomass and coal combustion sources appeared to have greater influence in the central Arctic Ocean, possibly due to the effects of episodic summertime forest fires. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Polycyclic aromatic compounds as anticancer agents: synthesis and biological evaluation of methoxy dibenzofluorene derivatives

    PubMed Central

    Becker, Frederick F.; Banik, Bimal K.

    2014-01-01

    Synthesis of a new methoxy dibenzofluorene through alkylation, cyclodehydration and aromatization in a one-pot operation is achieved for the first time. Using this hydrocarbon, a few derivatives are prepared through aromatic nitration, catalytic hydrogenation, coupling reaction with a side chain and reduction. The benzylic position of this hydrocarbon with the side chain is oxidized and reduced. Some of these derivatives have demonstrated excellent antitumor activities in vitro. This study confirms antitumor activity depends on the structures of the molecules. PMID:25136549

  16. Characterization of polycyclic aromatic compounds in diesel exhaust particulate extract responsible for aryl hydrocarbon receptor activity

    NASA Astrophysics Data System (ADS)

    Soontjens, Carol D.; Holmberg, Kristina; Westerholm, Roger N.; Rafter, Joseph J.

    Chemical fractions of a model diesel exhaust particulate extract, notably the fraction containing polycyclic aromatic hydrocarbons (PAH) (Fraction II), mono-nitro PAH (Fraction III), and dinitro-PAH (Fraction IV) have been shown to displace binding of 2,3,7,8-tetrachloro[1,6-[ 3H

  17. Removal of crude oil polycyclic aromatic hydrocarbons via organoclay-microbe-oil interactions.

    PubMed

    Ugochukwu, Uzochukwu C; Fialips, Claire I

    2017-05-01

    Clay minerals are quite vital in biogeochemical processes but the effect of organo-clays in the microbial degradation of crude oil polycyclic aromatic hydrocarbons is not well understood. The role of organo-saponite and organo-montmorillonite in comparison with the unmodified clays in crude oil polycyclic aromatic hydrocarbons (PAHs) removal via adsorption and biodegradation was studied by carrying out microcosm experiments in aqueous clay/oil systems with a hydrocarbon degrading microbial community that is predominantly alcanivorax spp. Montmorillonite and saponite samples were treated with didecyldimethylammonium bromide to produce organo-montmorillonite and organo-saponite used in this study. Obtained results indicate that clays with high cation exchange capacity (CEC) such as montmorillonite produced organo-clay (organomontmorillonite) that was not stimulatory to biodegradation of crude oil polycyclic aromatic compounds, especially the low molecular weight (LMW) ones, such as dimethylnaphthalenes. It is suggested that interaction between the organic phase of the organo-clay and the crude oil PAHs which is hydrophobic in nature must have reduced the availability of the polycyclic aromatic hydrocarbons for biodegradation. Organo-saponite did not enhance the microbial degradation of dimethylnaphthalenes but enhanced the biodegradation of some other PAHs such as phenanthrene. The unmodified montmorillonite enhanced the microbial degradation of the PAHs and is most likely to have done so as a result of its high surface area that allows the accumulation of microbes and nutrients enhancing their contact. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. EFFECT OF IRRADIANCE SPECTRA ON THE PHOTOINDUCED TOXICITY OF THREE POLYCYCLIC AROMATIC HYDROCARBONS

    EPA Science Inventory

    Photoinduced toxicity of polycyclic aromatic hydrocarbons (PAHs) is dependent on the concentration of compounds present and the dose of light received. Of the light present, only those wavelengths absorbed by the compound have the potential to initiate the photochemical events un...

  19. Polycyclic aromatic hydrocarbon hazards to fish, wildlife, and invertebrates: a synoptic review

    SciTech Connect

    Eisler, R.

    1987-05-01

    The report synthesizes technical literature on ecological and toxicological aspects of polycyclic aromatic hydrocarbons (PAH) in the environment, with special reference to fisheries and wildlife resources. Subtopics include: chemical properties, sources, and fate; background concentrations in biological and nonbiological samples; toxic and sublethal effects of PAH to flora and fauna; proposed criteria and research needs for the protection of sensitive, nonhuman organisms.

  20. Role of sooty mold fungi in degradation of polycycllic aromatic hydrocarbons (PAHS) in soil

    Treesearch

    Venera A. Jouraeva; David L. Johnson; John P. Hassett; David J. Nowak; Natalia A. Shipunova; Dana Barbarossa

    2006-01-01

    The focus of this research was on elucidation of the role of deciduous tree ecosystems in accumulation of fine-particle-associated polycyclic aromatic hydrocarbons (PAHs) and heavy metals on leaves of deciduous trees. The studied species were Tilia x euchlora (frequently infested by sooty mold fungi) and Pyrus calleryana (...

  1. SOLAR RADIATION DOSE AND PHOTOTOXICITY OF POLYCYCLIC AROMATIC HYDROCARBONS: A CASE STUDY

    EPA Science Inventory

    The toxicity of polycyclic aromatic hydrocarbons increases by as much as three orders of magnitude in the presence of solar radiation. The risk of this photoactive toxicity is thus based on both tissue concentrations of potentially photo activated compounds and the levels of subs...

  2. COMPARATIVE STUDIES OF THE EFFECT OF POLYCYCLIC AROMATIC HYDROCARBON GEOMETRY ON THE HYDROLYSIS OF DIOL EPOXIDES

    EPA Science Inventory

    Comparative studies of the effect of polycyclic aromatic hydrocarbon geometry on the hydrolysis of diol epoxides

    The interaction of the diol epoxides (DEs) of both planar and non-planar PAHs with water have been examined using quantum mechanical and molecular dynamics. Th...

  3. THE PHOTOTOXOICITY OF POLYCYCLIC AROMATIC HYDROCARBONS: A THEORETICAL STUDY OF EXCITED STATES AND CORRELATION TO EXPERIMENT

    EPA Science Inventory



    Investigators using models to determine the phototoxic effects of sunlight on polycyclic aromatic hydrocarbons (PAHS) have invoked the excited states of the molecule as important in elucidating the mechanism of these reactions. Energies of actual excited states were calcu...

  4. Sources and deposition of polycyclic aromatic hydrocarbons to western US national parks

    EPA Science Inventory

    Seasonal snowpack, lichens, and lake sediment cores were collected from fourteen lake catchments in eight western U.S. National Parks and analyzed for sixteen polycyclic aromatic hydrocarbons (PAHs) to determine their current and historical deposition, as well as to identify thei...

  5. PERSONAL EXPOSURES TO POLYCYCLIC AROMATIC HYDROCARBONS ASSOCIATED WITH THE NHEXAS PILOT

    EPA Science Inventory

    Personal exposure monitoring for select polycyclic aromatic hydrocarbons (PAHs) was performed as part of the National Human Exposure Assessment Survey (NHEXAS) Pilot Study in Baltimore, MD. Twenty-four hour PM10 sample collections (~5.7 m3) were performed using personal envi...

  6. Toxicity of polycyclic aromatic hydrocarbons. (Latest citations from Pollution abstracts). Published Search

    SciTech Connect

    1995-07-01

    The bibliography contains citations concerning the toxicity and biochemical effects of aromatic polycyclic hydrocarbons. Citations discuss air, water, soil, and sediment pollution and control. Topics include vehicle emissions and control, pollutant pathways, carcinogens and mutagenic activity, and photoinduced toxicity. Food contamination, environmental monitoring, and soil contamination along highways are examined. (Contains 50-250 citations and includes a subject term index and title list.)

  7. Coal-tar-based pavement sealcoat, polycyclic aromatic Hydrocarbons (PAHs), and environmental health

    USGS Publications Warehouse

    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.

  8. PERSONAL EXPOSURE TO FINE PARTICLE POLYCYCLIC AROMATIC HYDROCARBONS: OUTDOOR SOURCE TRACERS

    EPA Science Inventory


    The most carcinogenic and toxic polycyclic aromatic hydrocarbons (PAH) are the 4-5 ring PAH found preferentially adsorbed to the fine particles (<2.54u in urban ambient air and personal air. Personal exposure to the carcinogenic particle bound PAH is also highly correlated ...

  9. Fluorescence, Absorption, and Excitation Spectra of Polycyclic Aromatic Hydrocarbons as a Tool for Quantitative Analysis

    ERIC Educational Resources Information Center

    Rivera-Figueroa, A. M.; Ramazan, K. A.; Finlayson-Pitts, B. J.

    2004-01-01

    A quantitative and qualitative study of the interplay between absorption, fluorescence, and excitation spectra of pollutants called polycyclic aromatic hydrocarbons (PAHs) is conducted. The study of five PAH displays the correlation of the above-mentioned properties along with the associated molecular changes.

  10. Moss as bio-indicators of human exposure to polycyclic aromatic hydrocarbons in Portland, OR

    Treesearch

    Geoffrey H. Donovan; Sarah E. Jovan; Demetrios Gatziolis; Vicente J. Monleon

    2015-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are a class of air pollutants linked to a wide range of adverse health outcomes, including asthma, cancers, cardiovascular disease, and fetal growth impairment. PAHs are emitted by combustion of organic matter (e.g. fossil fuels, plant biomass) and can accumulate in plant and animal tissues over time. Compared to criteria...

  11. New SERS Substrates For Polycyclic Aromatic Hydrocarbon (PAH) Detection: Towards Quantitative SERS Sensors For Environmental Analysis

    SciTech Connect

    Peron, O.; Rinnert, E.; Compere, C.; Toury, T.; Lamy de la Chapelle, M.

    2010-08-06

    In the investigation of chemical pollutions, such as PAHs (Polycyclic Aromatic Hydrocarbons) at low concentration in aqueous medium, surface-enhanced Raman scattering (SERS) stands for an alternative to the inherent low cross-section of normal Raman scattering. Indeed, SERS is a very sensitive spectroscopic technique due to the excitation of the surface plasmon modes of the nanostructured metallic film.

  12. PERSONAL EXPOSURES TO POLYCYCLIC AROMATIC HYDROCARBONS ASSOCIATED WITH THE NHEXAS PILOT

    EPA Science Inventory

    Personal exposure monitoring for select polycyclic aromatic hydrocarbons (PAHs) was performed as part of the National Human Exposure Assessment Survey (NHEXAS) Pilot Study in Baltimore, MD. Twenty-four hour PM10 sample collections (~5.7 m3) were performed using personal envi...

  13. "Super-Reducing" Photocatalysis: Consecutive Energy and Electron Transfers with Polycyclic Aromatic Hydrocarbons.

    PubMed

    Brasholz, Malte

    2017-08-21

    Donation welcome: Recent developments in visible-light photocatalysis allow the utilization of increasingly negative reduction potentials. Successive energy and electron transfer with polycyclic aromatic hydrocarbons enables the catalytic formation of strongly reducing arene radical anions, classical stoichiometric reagents for one-electron reduction in organic synthesis. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. POLYCYCLIC AROMATIC HYDROCARBON FORMATION IN OPPOSED FLOW DIFFUSION FLAMES OF ETHANE. (R825412)

    EPA Science Inventory

    Abstract

    The effect of fuel-side carbon density on the levels of polycyclic aromatic hydrocarbon (PAH) formation in atmospheric pressure, opposed flow, ethane diffusion flames has been studied using heated micro-probe sampling and gas chromatography/mass spectrometry (...

  15. Determination of polycyclic aromatic hydrocarbons in biochar and biochar amended soil

    USDA-ARS?s Scientific Manuscript database

    A method for the determination of the 16 USEPA polycyclic aromatic hydrocarbons (PAHs) in biochar and soil amended with biochar was developed. Samples were Soxhlet extracted with acetone:cyclohexane 1:1, and PAHs were analysed by GC-MS after silica gel clean-up. In a comparative study based on reflu...

  16. THE EFFECT OF IRRADIANCE SPECTRA ON THE PHOTOACTIVATED TOXICITY OF THREE POLYCYCLIC AROMATIC HYDROCARBONS

    EPA Science Inventory

    Photoinduced toxicity of polycyclic aromatic hydrocarbons (PAHs) is dependent on the concentration of compounds present and the dose of light recieved. Of the light present, only those wavelengths absorbed by the compound have the potential to initiate the photochemical events un...

  17. Toxicity of aromatic polycyclic hydrocarbons. (Latest citations from the Life Sciences Collection database). Published Search

    SciTech Connect

    Not Available

    1994-11-01

    The bibliography contains citations concerning the toxicity and biochemical effects of aromatic polycyclic hydrocarbons. Topics include effects on metabolism and liver activity, cellular responses, binding characteristics, and the occurrence and path of the compounds in food chains. Bioaccumulation studies in specific areas, and isolation and detection techniques are also considered. (Contains 250 citations and includes a subject term index and title list.)

  18. Toxicity of aromatic polycyclic hydrocarbons. (Latest citations from the Life Sciences Collection database). Published Search

    SciTech Connect

    Not Available

    1993-11-01

    The bibliography contains citations concerning the toxicity and biochemical effects of aromatic polycyclic hydrocarbons. Topics include effects on metabolism and liver activity, cellular responses, binding characteristics, and the occurrence and path of the compounds in food chains. Bioaccumulation studies in specific areas, and isolation and detection techniques are also considered. (Contains 250 citations and includes a subject term index and title list.)

  19. COMPARATIVE STUDIES OF THE EFFECT OF POLYCYCLIC AROMATIC HYDROCARBON GEOMETRY ON THE HYDROLYSIS OF DIOL EPOXIDES

    EPA Science Inventory

    Comparative studies of the effect of polycyclic aromatic hydrocarbon geometry on the hydrolysis of diol epoxides

    The interaction of the diol epoxides (DEs) of both planar and non-planar PAHs with water have been examined using quantum mechanical and molecular dynamics. Th...

  20. Polycyclic aromatic hydrocarbon migration from creosote-treated railway ties into ballast and adjacent wetlands

    Treesearch

    Kenneth M. Brooks

    2004-01-01

    Occasionally, creosote-treated railroad ties need to be replaced, sometimes in sensitive environments such as wetlands. To help determine if this is detrimental to the surrounding environment, more information is needed on the extent and pattern of creosote, or more specifically polycyclic aromatic hydrocarbon (PAH), migration from railroad ties and what effects this...

  1. THE PHOTOTOXOICITY OF POLYCYCLIC AROMATIC HYDROCARBONS: A THEORETICAL STUDY OF EXCITED STATES AND CORRELATION TO EXPERIMENT

    EPA Science Inventory



    Investigators using models to determine the phototoxic effects of sunlight on polycyclic aromatic hydrocarbons (PAHS) have invoked the excited states of the molecule as important in elucidating the mechanism of these reactions. Energies of actual excited states were calcu...

  2. Fluorescence, Absorption, and Excitation Spectra of Polycyclic Aromatic Hydrocarbons as a Tool for Quantitative Analysis

    ERIC Educational Resources Information Center

    Rivera-Figueroa, A. M.; Ramazan, K. A.; Finlayson-Pitts, B. J.

    2004-01-01

    A quantitative and qualitative study of the interplay between absorption, fluorescence, and excitation spectra of pollutants called polycyclic aromatic hydrocarbons (PAHs) is conducted. The study of five PAH displays the correlation of the above-mentioned properties along with the associated molecular changes.

  3. Particle in a Disk: A Spectroscopic and Computational Laboratory Exercise Studying the Polycyclic Aromatic Hydrocarbon Corannulene

    ERIC Educational Resources Information Center

    Frey, E. Ramsey; Sygula, Andrzej; Hammer, Nathan I.

    2014-01-01

    This laboratory exercise introduces undergraduate chemistry majors to the spectroscopic and theoretical study of the polycyclic aromatic hydrocarbon (PAH), corannulene. Students explore the spectroscopic properties of corannulene using UV-vis and Raman vibrational spectroscopies. They compare their experimental results to simulated vibrational…

  4. Sources and deposition of polycyclic aromatic hydrocarbons to western US national parks

    EPA Science Inventory

    Seasonal snowpack, lichens, and lake sediment cores were collected from fourteen lake catchments in eight western U.S. National Parks and analyzed for sixteen polycyclic aromatic hydrocarbons (PAHs) to determine their current and historical deposition, as well as to identify thei...

  5. POLYCYCLIC AROMATIC HYDROCARBON BIODEGRADATION AS A FUNCTION OF OXYGEN TENSION IN CONTAMINATED SOIL

    EPA Science Inventory

    Laboratory tests were conducted to determine the effect of soil gas oxygen concentration on the degradation and mineralization of spiked 14C-pyrene and nonspiked 16 priority pollutant polycyclic aromatic hydrocarbons (PAH) present in the soil. The soil used for the evaluation was...

  6. Particle in a Disk: A Spectroscopic and Computational Laboratory Exercise Studying the Polycyclic Aromatic Hydrocarbon Corannulene

    ERIC Educational Resources Information Center

    Frey, E. Ramsey; Sygula, Andrzej; Hammer, Nathan I.

    2014-01-01

    This laboratory exercise introduces undergraduate chemistry majors to the spectroscopic and theoretical study of the polycyclic aromatic hydrocarbon (PAH), corannulene. Students explore the spectroscopic properties of corannulene using UV-vis and Raman vibrational spectroscopies. They compare their experimental results to simulated vibrational…

  7. Enumeration and phylogenetic analysis of polycyclic aromatic hydrocarbon-degrading marine bacteria from Puget Sound sediments

    SciTech Connect

    Geiselbrecht, A.D.; Herwig, R.P.; Deming, J.W.; Staley, J.T.

    1996-09-01

    Polycyclic aromatic hydrocarbons (PAHs) are primarily released into the environment through anthropomorphic sources. PAH degradation has been known to occur in marine sediments. This paper describes the enumeration, isolation, and preliminary characterization of PAH-degrading strains from Puget Sound sediments. 38 refs., 3 figs., 3 tabs.

  8. Bacterial biodegradation of polycyclic aromatic hydrocarbons (PAH) and potential effects of surfactants on PAH bioavailability

    SciTech Connect

    Aitken, M.D.; Grimberg, S.J.; Nagel, J.; Nagel, R.D.; Stringfellow, W.T.

    1996-02-01

    The purposes of this project were to evaluate whether indigenous microorganisms from polycyclic aromatic hydrocarbons (PAH)-contaminated soils produce surfactants (biosurfactants) as a means of enhancing the bioavailability of PAH; to improve the understanding of the general physiology of a diverse group of PAH-degrading bacteria; and to study in general how surfactants influence the biodegradation of hydrophobic chemicals.

  9. POLYCYCLIC AROMATIC HYDROCARBON BIODEGRADATION AS A FUNCTION OF OXYGEN TENSION IN CONTAMINATED SOIL

    EPA Science Inventory

    Laboratory tests were conducted to determine the effect of soil gas oxygen concentration on the degradation and mineralization of spiked 14C-pyrene and nonspiked 16 priority pollutant polycyclic aromatic hydrocarbons (PAH) present in the soil. The soil used for the evaluation was...

  10. EFFECT OF IRRADIANCE SPECTRA ON THE PHOTOINDUCED TOXICITY OF THREE POLYCYCLIC AROMATIC HYDROCARBONS

    EPA Science Inventory

    Photoinduced toxicity of polycyclic aromatic hydrocarbons (PAHs) is dependent on the concentration of compounds present and the dose of light received. Of the light present, only those wavelengths absorbed by the compound have the potential to initiate the photochemical events un...

  11. THE EFFECT OF IRRADIANCE SPECTRA ON THE PHOTOACTIVATED TOXICITY OF THREE POLYCYCLIC AROMATIC HYDROCARBONS

    EPA Science Inventory

    Photoinduced toxicity of polycyclic aromatic hydrocarbons (PAHs) is dependent on the concentration of compounds present and the dose of light recieved. Of the light present, only those wavelengths absorbed by the compound have the potential to initiate the photochemical events un...

  12. Sediment porewater partitioning of polycyclic aromatic hydrocarbons in three cores from Boston Harbor, Massachusetts

    USGS Publications Warehouse

    Mcgroddy, S.E.; Farrington, J.W.

    1995-01-01

    Polycyclic aromatic hydrocarbon (PAH) concentrations were measured in sediments and porewaters isolated from three cores from Boston Harbor, MA. Measured porewater PAH concentrations were significantly lower than the concentrations predicted by two- and three-phase equilibrium partitioning models. We hypothesize that only a fraction of the measured sediment PAH concentrations was available to partition rapidly into sediment porewaters. ?? 1995 American Chemical Society.

  13. Occupational exposure to aromatic hydrocarbons and polycyclic aromatic hydrocarbons at a coke plant.

    PubMed

    Bieniek, Grażyna; Łusiak, Agnieszka

    2012-08-01

    The objective of this study was to assess the external exposure to aromatic hydrocarbons (AHs) and polycyclic aromatic hydrocarbons (PAHs) of coke-oven workers and by-product workers at a coke plant in Poland. The content of benzene, toluene, xylene, and naphthalene in a gaseous phase and the content of dibenzo[a,h]anthracene, benz[a]anthracene, anthracene, benzo[a]pyrene, benzo[b]fluoranthene, benzo[k]fluoranthene, benz[ghi]perylene, chrysene, and indeno[1,2,3-c,d]pyrene in a particulate phase of coke plant workers were measured in the workers mentioned above. A toxic equivalency factor BaP(eq) was used to estimate human health risk associated with respiratory exposure to PAHs. Time-weighted values of the exposure to AHs in the coke plant were as follows: benzene (range 0.01-2.71 mg m(-3)), toluene (0.01-1.73 mg m(-3)), xylene (0.01-0.78 mg m(-3)), naphthalene (6.0-6079 μg m(-3)), and the concentrations of hydrocarbons did not exceed the exposure limits. The results for particle-bound PAHs were equal to 1.96 μg m(-3) for B(a)P, 0.73 μg m(-3) for DBA, 3.23 μg m(-3) for BaA, 4.35 μg m(-3) for BbF, 3.02 μg m(-3) for BkF, 4.54 μg m(-3) for IND, 4.32 μg m(-3) for CHR, and 0.73 μg m(-3) for Ant. The results of personal air measurements (median values of the sum of nine carcinogenic PAHs) were 2.115 μg m(-3) (coke-oven workers, n = 207), 0.326 μg m(-3) (coke by-product workers, n = 33), and 0.653 μg m(-3) (total area workers, n = 38). The benzo[a]pyrene equivalent concentrations (BaP(eq)) of 10 PAHs were 1.33, 0.183, and 0.284 μg m(-3), respectively. We found out that coke plant workers are simultaneously exposed to a mixture of aromatic and polycyclic hydrocarbons present in the breathing zone air. Exposure levels are significantly influenced by job categories. Coke by-product workers are significantly more exposed to benzene, toluene, and xylene and less to PAHs. Coke-oven workers are mainly exposed to PAHs. Coke-oven workplaces (top side, coke side, and

  14. Applications of electrochemically-modulated liquid chromatography (EMLC): Separations of aromatic amino acids and polycyclic aromatic hydrocarbons

    SciTech Connect

    Deng, Li

    1998-03-27

    The research in this thesis explores the separation capabilities of a new technique termed electrochemically-modulated liquid chromatography (EMLC). The thesis begins with a general introduction section which provides a literature review of this technique as well as a brief background discussion of the two research projects in each of the next two chapters. The two papers which follow investigate the application of EMLC to the separation of a mixture of aromatic amino acids and of a mixture of polycyclic aromatic hydrocarbons (PAHs). The last section presents general conclusions and summarizes the thesis. References are compiled in the reference section of each chapter. The two papers have been removed for separate processing.

  15. Airborne Exposures to Polycyclic Aromatic Compounds Among Workers in Asphalt Roofing Manufacturing Facilities.

    PubMed

    Trumbore, David C; Osborn, Linda V; Johnson, Kathleen A; Fayerweather, William E

    2015-01-01

    We studied exposure of 151 workers to polycyclic aromatic compounds and asphalt emissions during the manufacturing of asphalt roofing products-including 64 workers from 10 asphalt plants producing oxidized, straight-run, cutback, and wax- or polymer-modified asphalts, and 87 workers from 11 roofing plants producing asphalt shingles and granulated roll roofing. The facilities were located throughout the United States and used asphalt from many refiners and crude oils. This article helps fill a gap in exposure data for asphalt roofing manufacturing workers by using a fluorescence technique that targets biologically active 4-6 ring polycyclic aromatic compounds and is strongly correlated with carcinogenic activity in animal studies. Worker exposures to polycyclic aromatic compounds were compared between manufacturing plants, at different temperatures and using different raw materials, and to important external benchmarks. High levels of fine limestone particulate in the plant air during roofing manufacturing increased polycyclic aromatic compound exposure, resulting in the hypothesis that the particulate brought adsorbed polycyclic aromatic compounds to the worker breathing zone. Elevated asphalt temperatures increased exposures during the pouring of asphalt. Co-exposures in these workplaces which act as confounders for both the measurement of total organic matter and fluorescence were detected and their influence discussed. Exposures to polycyclic aromatic compounds in asphalt roofing manufacturing facilities were lower than or similar to those reported in hot-mix paving application studies, and much below those reported in studies of hot application of built-up roofing asphalt. These relatively low exposures in manufacturing are primarily attributed to air emission controls in the facilities, and the relatively moderate temperatures, compared to built-up roofing, used in these facilities for oxidized asphalt. The exposure to polycyclic aromatic compounds was a very

  16. Polycyclic aromatic hydrocarbons in the South American environment.

    PubMed

    Barra, Ricardo; Castillo, Caroline; Torres, Joao Paulo Machado

    2007-01-01

    Pollution of the environment with polycyclic aromatic hydrocarbons (PAHs) should be a global concern, especially in urbanized areas. In South American countries, where notable increase in urban populations has been observed in the past few years, reliable information about the pollution status of these urban environments is not always easily accessible, and therefore an effort to collect updated information is required. This review attempts to contribute by analyzing the existing information regarding environmental levels of PAHs in some South American countries. A regional trend for environmental PAH information is an uneven contribution, because some countries, such as Bolivia, Peru, Paraguay, and Ecuador, have reported no information at all in the scientific literature, reflecting to a certain extent the different patterns of economic, technical, and scientific development. PAH air monitoring is one of the areas that has received the most attention during the last few years, mainly in Brazil, Chile, and Argentina, where data represent a few geographical areas within the region. PAH levels in air from some urban areas in Argentina, Brazil, and Chile, considered moderate to high (100-1000ng/m3), are probably among the highest values reported in the open literature. Urbanization, vehicle pollution, and wood fires are the principal contributors to the high reported levels. In more temperate areas, a clear distinction is observed between summer and winter levels. PAH monitoring in soils is very limited within the region, with few data available, and most information indicates widespread pollution. In Brazil, values for many representative ecosystems were found. In Chile, data from forestry and agricultural areas indicate in general low concentrations, in spite of a relatively high detection frequency. Pollution levels in soils are highly dependent on their closeness to PAH sources and certain cultural practices (agricultural burnings, forest fires, etc.). Water PAH

  17. Polycyclic Aromatic Hydrocarbons in an industrialized urban area

    NASA Astrophysics Data System (ADS)

    Cachada, A.; Pereira, R.; Ferreira da Silva, E.; Duarte, A. C.

    2009-04-01

    Urbanization, agricultural intensification and industrialization are contributing to erosion, local and diffuse contamination and sealing of soil surfaces, resulting in soil quality degradation. Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in urban environments and considered good markers of anthropogenic activities such as traffic, industry, domestic heating and agriculture. Although they are subject to biodegradation and photodegradation, once in the soil, they tend to bind to the soil organic fraction. Estarreja is a small coastal town in the Northwestern Portuguese coast, with a close relation with the lagoon of Aveiro which supports a variety of biotopes (channels, islands with vegetation, mudflats, salt marshes and agricultural fields) of important ecological value. It supports an intensive and diversified agriculture, a variety of heavy and light industries and a population of about half a million people which is dependent on this resource. This is a very industrialized area, due to its five decades of chemical industry. This study aims to assess the impact of the urbanization and of the chemical industry in PAHs distribution. The survey and sampling method were based on pre-interpreted maps, aerial photographs, and directly checked in the field, in order to get an overall characterization of the area. Topsoils were collected from 34 sites, considering different land uses. Five land uses were chosen: ornamental gardens, parks, roadsides, forest and agricultural. Parameters such as soil pH (ISO method 10390:1994), total C, N, H, S percentages (microanalyser LECO, CNHS-932), organic matter (LOI at 430°), particle size distribution (Micromeritics® Sedigraph 5100), cation exchange capacity and exchangeable bases, were determined in order to have a general characterization of soil. Determination of the 16 EPA PAHs in soils was performed by GC/MS after a Soxhlet extraction and an alumina clean-up of extracts. Procedure blanks, duplicates and reference

  18. Peat fires as source of polycyclic aromatic hydrocarbons in soils

    NASA Astrophysics Data System (ADS)

    Tsibart, Anna

    2013-04-01

    Polycyclic aromatic hydrocarbons (PAHs) arrive from pyrogenic sources including volcanism and the combustion of oil products and plant materials. The production of PAHs during the combustion of plant materials was considered in a number of publications, but their results were mainly obtained in laboratory experiments. Insufficient data are available on the hightemperature production of PAHs in environmental objects. For example, natural fires are frequently related to the PAH sources in landscapes, but very little factual data are available on this topic. On Polistovskii reserve (Russia, Pskov region) the soil series were separated depending on the damage to the plants; these series included soils of plots subjected to fires of different intensities, as well as soils of the background plots. The series of organic and organomineral soils significantly differed in their PAH distributions. In this series, the concentration of PAHs in the upper horizons of the peat soils little varied or slightly decreased, but their accumulation occurred at a depth of 5-10 or 10-20 cm in the soils after the fires. For example, in the series of high moor soils, the content of PAHs in the upper horizons remained almost constant; significant differences were observed in the subsurface horizons: from 2 ng/g in the background soil to 70 ng/g after the fire. In the upper horizons of the oligotrophic peat soils under pine forests, the total PAH content also varied only slightly. At the same time, the content of PAHs in the soil series increased from 15 to 90 ng/g with the increasing pyrogenic damage to the plot. No clear trends of the PAH accumulation were recorded in the organomineral soils. The content of PAHs in the soddy-podzolic soil subjected to fire slightly decreased (from 20 to 10 ng/g) compared to the less damaged soil. In peat fires, the access of oxygen to the fire zone is lower than in forest fires. The oxygen deficit acts as a factor of the organic fragments recombination and

  19. Distribution of polycyclic aromatic hydrocarbons in soils and terrestrial biota after a spill of crude oil in Trecate, Italy.

    PubMed

    Brandt, Charles A; Becker, James M; Porta, Augusto

    2002-08-01

    Ecological and human health exposures from soil-based petroleum-derived contaminants commonly are estimated by using soil-to-biota transfer factors that usually are based on octanol-water partitioning. Few studies of biota have been conducted in relation to spills of crude oils in terrestrial environments. After a large blowout of crude oil in northern Italy in 1994, the distribution of polycyclic aromatic hydrocarbons (PAHs) was examined over time and space in soils, uncultivated wild vegetation, insects, mice, and frogs in the area. Within two years of the blowout, PAH concentrations declined to background levels over much of the area where initial concentrations were within an order of magnitude above background, but had not declined to background in areas where starting concentrations exceeded background by two orders of magnitude. Octanol-water partitioning and extent of alkylation explained much of the variance in uptake of PAHs by plants and animals. The PAHs with lower octanol-water partition coefficients (K(ow)s) and higher-alkylated PAHs had higher biota-soil accumulation factors (BSAFs) than did high-K(ow) and unalkylated forms. The BSAFs for PAHs with higher K(ow)s were very low for plants, but much higher for animals, with frogs accumulating more of these compounds than other species.

  20. Analysis of polycyclic aromatic hydrocarbons using desorption atmospheric pressure chemical ionization coupled to a portable mass spectrometer.

    PubMed

    Jjunju, Fred P M; Maher, Simon; Li, Anyin; Badu-Tawiah, Abraham K; Taylor, Stephen; Cooks, R Graham

    2015-02-01

    Desorption atmospheric pressure chemical ionization (DAPCI) is implemented on a portable mass spectrometer and applied to the direct detection of polycyclic aromatic hydrocarbons (PAHs) and alkyl substituted benzenes. The presence of these compounds in the environment poses a significant threat to the health of both humans and wildlife because of their carcinogenic, toxic, and mutagenic properties. As such, instant detection outside of the laboratory is of particular importance to allow in-situ measurement at the source. Using a rapid, high throughput, miniature, handheld mass spectrometer, several alkyl substituted benzenes and PAHs (i.e., 1,2,3,5-tetramethylbenzene, pentamethylbenzene, hexamethylbenzene, fluoranthene, anthracene, benzo[k]fluoranthene, dibenz[a,h]anthracene, acenaphthene, indeno[1,2,3-c,d]pyrene, 9-ethylfluorene, and 1-benzyl-3-methyl-naphthalene) were identified and characterized using tandem mass spectrometry (MS/MS) from ambient surfaces, in the open air. This method can provide almost instantaneous information while minimizing sample preparation, which is advantageous in terms of both cost and simplicity of analysis. This MS-based technique is applicable to a wide range of environmental organic molecules.

  1. A wintertime investigation of atmospheric deposition of metals and polycyclic aromatic hydrocarbons in the Athabasca Oil Sands Region, Canada.

    PubMed

    Bari, M A; Kindzierski, W B; Cho, S

    2014-07-01

    With planned expansion of oil sands facilities, there is interest in being able to characterize the magnitude and extent of deposition of metals and polycyclic aromatic hydrocarbons (PAH) in the Athabasca Oil Sands Region (AOSR) of Alberta. A study was undertaken using a bulk collection system to characterize wintertime atmospheric deposition of selected inorganic and organic contaminants in the AOSR. The study was carried out from January to March 2012 at two sampling sites near (within a 20 km circle of oil sands development) and two sampling sites distant (>45 km) to oil sands development. Triplicate bulk samplers were used to estimate precision of the method at one distant site. Monthly deposition samples were analyzed for 36 metals, ultra-low mercury, and 25 PAHs (including alkylated, and parent PAH). At the two sites located within 20 km of oil sands development, 3-month wintertime integrated deposition for some priority metals, alkylated and parent PAH were higher compared to distant sites. Deposition fluxes of metals and PAH were compared to other available bulk deposition studies worldwide. Median bulk measurement uncertainties of metals and both PAH classes were 26% and within ±15%, respectively suggesting that the bulk sampling method is a potential alternative for obtaining future direct measures of wintertime metals and PAH deposition at locations without access to power in the AOSR.

  2. Determination of chlorinated polycyclic aromatic hydrocarbons in water by solid-phase extraction coupled with gas chromatography and mass spectrometry.

    PubMed

    Wang, Xianli; Kang, Haiyan; Wu, Junfeng

    2016-05-01

    Given the potential risks of chlorinated polycyclic aromatic hydrocarbons, the analysis of their presence in water is very urgent. We have developed a novel procedure for determining chlorinated polycyclic aromatic hydrocarbons in water based on solid-phase extraction coupled with gas chromatography and mass spectrometry. The extraction parameters of solid-phase extraction were optimized in detail. Under the optimal conditions, the proposed method showed wide linear ranges (1.0-1000 ng/L) with correlation coefficients ranging from 0.9952 to 0.9998. The limits of detection and the limits of quantification were in the range of 0.015-0.591 and 0.045-1.502 ng/L, respectively. Recoveries ranged from 82.5 to 102.6% with relative standard deviations below 9.2%. The obtained method was applied successfully to the determination of chlorinated polycyclic aromatic hydrocarbons in real water samples. Most of the chlorinated polycyclic aromatic hydrocarbons were detected and 1-monochloropyrene was predominant in the studied water samples. This is the first report of chlorinated polycyclic aromatic hydrocarbons in water samples in China. The toxic equivalency quotients of chlorinated polycyclic aromatic hydrocarbons in the studied tap water were 9.95 ng the toxic equivalency quotient m(-3) . 9,10-Dichloroanthracene and 1-monochloropyrene accounted for the majority of the total toxic equivalency quotients of chlorinated polycyclic aromatic hydrocarbons in tap water.

  3. Occurrence and concentrations of polycyclic aromatic hydrocarbons in semipermeable membrane devices and clams in three urban streams of the Dallas-Fort Worth Metropolitan Area, Texas

    USGS Publications Warehouse

    Moring, J.B.; Rose, D.R.

    1997-01-01

    Semipermeable membrane devices (SPMDs) and Asiatic clams, Corbicula fluminea (MuLLER), were deployed at stream sites in the Dallas-Fort Worth Metropolitan Area to assess the presence of bioavailable, dissolved polycyclic aromatic hydrocarbons (PAHs). Twenty-four PAHs were detected in SPMDs, 20 of which occurred at all sites. Only three PAHs were detected in the co-deployed clams. Throughout all sites, non-alkylated PAHs were found at greater levels in SPMDs than alkylated forms. Nine of 16 Priority Pollutant PAHs were detected in SPMDs. Estimated concentrations of PAHs in water were generally two to three orders of magnitude less than standard minimum analytical reporting levels; however, for bent (a) anthracene, benzo (a) pyrene, and chrysene, estimated concentrations in water exceeded the U.S. Environmental Protection Agency's human health criteria for these carcinogens in water and aquatic organisms.

  4. UV irradiation of polycyclic aromatic hydrocarbons in ices: production of alcohols, quinones, and ethers

    NASA Technical Reports Server (NTRS)

    Bernstein, M. P.; Sandford, S. A.; Allamandola, L. J.; Gillette, J. S.; Clemett, S. J.; Zare, R. N.

    1999-01-01

    Polycyclic aromatic hydrocarbons (PAHs) in water ice were exposed to ultraviolet (UV) radiation under astrophysical conditions, and the products were analyzed by infrared spectroscopy and mass spectrometry. Peripheral carbon atoms were oxidized, producing aromatic alcohols, ketones, and ethers, and reduced, producing partially hydrogenated aromatic hydrocarbons, molecules that account for the interstellar 3.4-micrometer emission feature. These classes of compounds are all present in carbonaceous meteorites. Hydrogen and deuterium atoms exchange readily between the PAHs and the ice, which may explain the deuterium enrichments found in certain meteoritic molecules. This work has important implications for extraterrestrial organics in biogenesis.

  5. Vapor pressures and enthalpies of sublimation of polycyclic aromatic hydrocarbons and their derivatives

    SciTech Connect

    Oja, V.; Suuberg, E.M.

    1998-05-01

    The vapor pressures of a series of polycyclic aromatic hydrocarbons (PAH) and heteroatom-containing PAH have been measured using the Knudsen effusion technique. Aromatic hydrocarbons examined included anthracene, phenanthrene, pyrene, 2,3-benzofluorene, naphthacene, perylene, pentacene, and coronene. Heteroatomic aromatic species examined included phenanthridine, perinaphthenone, 3-hydroxy-1-phenalen-1-one, benz[g]isoquinoline-5,10-dione, 1,2-benzodiphenylene sulfide, 1-hydroxypyrene, and 6,11-dihydroxy-5,12-naphthacenedione. The measurements were all made in the solid sublimation regime, and enthalpies of sublimation were calculated from the Clausius-Clapeyron equation.

  6. Source characterization of polycyclic aromatic hydrocarbons by using their molecular indices: an overview of possibilities.

    PubMed

    Stogiannidis, Efstathios; Laane, Remi

    2015-01-01

    In recent decades. an exponential increase in the concentration of anthropogenic Polycyclic Aromatic Hydrocarbons (PAHs; see Table I for a li st of PAH abbreviations) has been observed worldwide. Regulators need to know the sources if concentrations are to be reduced and appropriate remediation measures taken. "Source characterization of PAHs" involves linking these contaminants to their sources. Scientists place PAH sources into three classes: pyrogenic, petrogenic. and natural. In this review. we investigate the possibility of using PAH molecular ratios individually or in combination for the purpose of deducing the petrogenic or pyrogenic origin of the contamination in sediments. We do this by reviewing the characteristic PAH patterns of the sources and by taking into account the fate of PAHs in the aquatic environment. Many PAH indicators have been developed for the purpose of discriminating different PAH sources. In Table 4 we summarize the applicability of different PAH ratios and threshold values. The analysis of two- to four-ringed alkylated PAH soilers the possibility to distinguish two or more single sources or categories of pollution in greater detail. For example. the FLO/PYO. the PPI. and PO/AO ratios can be used to discriminate between pyrogenic and petrogcnic sources of contamination. When petrogenic contamination is suspected. chrysenes. PAHs lighter than CO. and in particular. alkylated PAHs can usually be of use. For unburned coal PAHs. The methylphenanthrenic ratios (MP!s). the 1-D I/4- DI. and BbF/BkF are promising, since they are sometimes correlated with vitrinite rellectance (coal ranks). Alkylphenanthrenes can be used to detect biomass combustion. Higher molecular weight parent and alkylated PAHs are appropriate for pyrogenic discriminations. When PAH indices are coupled with discriminant analysis techniques such as PMF (positive matrix factorization),the origin of multiple sources in even the most complex environments can be traced and

  7. High molecular weight polycyclic aromatic hydrocarbons in hydrothermal petroleums - indicators of high temperatures and water washing

    SciTech Connect

    Simoneit, B.R.T.; Fetzer, J.C.

    1995-06-01

    Hydrothermal petroleums from active sedimented oceanic spreading axes contain polycyclic aromatic hydrocarbons (PAH) as characteristic components of their rapid high temperature genesis. The unsubstituted PAH dominate over their alkyl-substituted homologs and occur at high concentrations relative to the aliphatic components, which distinguishes hydrothermal petroleums from conventional reservoir petroleums. Some of the samples contain PAH with higher molecular weights than coronene (M.W. 300) and here we describe the structures and distributions of these PAH in typical examples of petroleums from Guaymas Basin, Escanaba Trough and Middle Valley. Some of the aromatic fractions (F2) show PAH of up to nine rings [e.g., dibenzo-(e,ghi)perylene, benzo(a)coronene, benzo(pqr)naphtho(8,1,2-bcd)perylene, naphtho(8,1,2-abc)coronene]. Fraction 3 in some of these samples has ovalene, a condensed ten-ring PAH. These PAH are the most thermodynamically stable structures for each ring number, and are most likely indicative of a one-ring build-up mechanism. The samples also contain a few specific PAHs [e.g., the seven-ring PAH dibenzo(cd,lm)perylene] which are not members of this stable class. Its formation mechanism must be very specific through the condensation of a pair of the three-ring phenalene radicals or through the Scholl-condensation of pyrene to a nine-ring PAH with its subsequent hydrogenation and cracking down to dibenzo(cd,lm)-perylene. This is the first report of the occurrence of heavy PAH (M.W. >300) in geological samples. They are concentrated in the bitumens by removal of the lower molecular weight PAH due to mixing during hydrothermal fluid/oil transport and selective deposition/solidification of the heavy ends at the seabed with concurrent loss of the more water soluble and lower weight products to the ambient seawater. Additional post-depositional reworking by hot fluids and biodegradation further enhance the enrichment of the heavy PAH.

  8. Release of polycyclic aromatic compounds into a Mediterranean creek (Catalonia, NE Spain) after a forest fire.

    PubMed

    Vila-Escalé, M; Vegas-Vilarrúbia, T; Prat, N

    2007-05-01

    Wildfires produce polycyclic aromatic compounds (PACs), among which polycyclic aromatic hydrocarbons (PAHs) are of environmental concern. After a fire affecting a Mediterranean creek, we studied the distribution and short-term permanence of PACs and of 16 priority PAH pollutants in the aquatic environment. PACs were traced through absorbance and fluorescence emissions and organic carbon concentrations. PAHs were analysed by gas chromatography. High TOC/DOC concentrations and fluorescence/absorbance values reflected abnormal inputs of fire-induced aromatic compounds. Their concentrations decreased gradually but showed sporadic peaks after precipitation. Fifteen months later, values still surpassed background levels. Initially concentrations of individual and total PAH species of the dissolved, particulate and sediment phases were increased. Then they fluctuated with new PAH inputs related with runoff, leaching and soil erosion following precipitation events. All PAH concentrations approached background levels 15 months after the fire, and never reached values of toxicological concern. However, some bioaccumulation may have occurred.

  9. Microbial community structure of a heavy fuel oil-degrading marine consortium: linking microbial dynamics with polycyclic aromatic hydrocarbon utilization.

    PubMed

    Vila, Joaquim; María Nieto, José; Mertens, Jelle; Springael, Dirk; Grifoll, Magdalena

    2010-08-01

    A marine microbial consortium obtained from a beach contaminated by the Prestige oil spill proved highly efficient in removing the different hydrocarbon families present in this heavy fuel oil. Seawater cultures showed a complete removal of all the linear and branched alkanes, an extensive attack on three to five-ring polycyclic aromatic hydrocarbons [PAHs; including anthracene, fluoranthene, pyrene, benzo(a)anthracene, chrysene, and benzo(a)pyrene] (30-100%), and a considerable depletion of their alkyl derivatives. Community dynamics analysis revealed that Alcanivorax species, known alkane degraders, predominated in the initial stages. This was followed by an increase in Alphaproteobacteria (i.e. Maricaulis, Roseovarius), which coincided with the depletion of low molecular PAHs. Finally, these were succeeded by Gammaproteobacteria (mainly Marinobacter and Methylophaga), which were involved in the degradation of the high molecular-weight PAHs. The role of these populations in the removal of the specific components was confirmed by the analysis of subcultures established using the aliphatic or the aromatic fraction of the fuel oil, or single PAHs, as carbon sources. The genus Marinobacter seemed to play a major role in the degradation of a variety of hydrocarbons, as several members of this group were isolated from the different enrichment cultures and grew on plates with hexadecane or single PAHs as sole carbon sources.

  10. Stability of polycyclic aromatic compounds in polyurethane foam-type passive air samplers upon O3 exposure

    NASA Astrophysics Data System (ADS)

    Jariyasopit, Narumol; Liu, Yongchun; Liggio, John; Harner, Tom

    2015-11-01

    Stability of polycyclic aromatic compounds (PACs) in polyurethane foam (PUF) disks upon O3 exposure was studied in a flow tube. A wide range of PACs was evaluated by spiking PUF disks with PACs and exposing to O3 at concentrations that were equivalent to two months exposure, a typical deployment period for these passive air samplers. Ambient concentrations of O3 (∼50 ppb) at 0% and 50% relative humidity (RH) were applied. At 0% RH, 23 of 68 PACs yielded more than 50% loss after exposure. The mean percent loss was 30% with perylene and 9,10-dimethylanthracene the most reactive polycyclic aromatic hydrocarbons (PAHs) and alkylated PAHs, respectively. At 50% RH, 77% of the studied PACs was stable upon O3 exposure (PACexposed/PACunexposed > 0.7). The mean percent loss was 17% and only 7 of 68 PACs yielded greater than 50% loss. In general, the reactivity of most of the PACs decreased at higher RH, except for the reactive PAHs (acenaphthylene, 2,3-dimethylanthracene, 9,10-dimethylanthracene, dibenzothiophene, and 2-methyldibenzothiophene) which demonstrated lower RH dependence. The experimental conditions in this study represent a worst case scenario for the stability of PACs sorbed to PUF. In reality, the sampling of PACs in ambient air represents an 'aged' component of PACs where the most reactive species have already partially been removed. Also, PACs in ambient air will be associated with the particle phase to varying extents that will help to enhance their stability. Therefore, under regular operating conditions, over a 2-month exposure, we expect a minimal error in the measurement of total concentration of PACs in air using the PUF disk passive sampler.

  11. Nitrated polycyclic aromatic hydrocarbons in urban air particles

    SciTech Connect

    Ramdahl, T.; Becher, G.; Bjorseth, A.

    1982-12-01

    The organic extract of urban air particles from St. Louis, MO, was fractionated by high-performance liquid chromatography. The moderately polar fraction was characterized by gas chromatography-electron impact and methane negative ion chemical ionization mass spectrometry. The compounds identified in the sample included nitronaphthalene, 9-nitroanthracene, 3-nitrofluoranthene, 1-nitropyrene, arenecarbonitriles, and several polycyclic ketones, quinones, and anhydrides. These studies represent the first mass spectrometric evidence of nitroaromatics in urban air particles.

  12. Production of alkyl-aromatics from light oxygenates over zeolite catalysts for bio-oil refining

    NASA Astrophysics Data System (ADS)

    Hoang, Trung Q.

    in aromatic yield. Further improvement of aromatization and catalyst lifetime was also found with ZnHZSM-5 wherein the Zn evidently modifies the acidity. These model compound results show that the optimized use of zeolites for production of alkyl aromatics from light oxygenates at mild conditions may be effective for bio-oil refining.

  13. IMPORTANCE OF MATERNAL TRANSFER OF THE PHOTOREACTIVE POLYCYCLIC AROMATIC HYDROCARBON FLUORANTHENE FROM BENTHIC ADULT BIVALVES TO THEIR PELAGIC LARVAE

    EPA Science Inventory

    Laboratory experiments were conducted to determine if maternal transfer of polycyclic aromatic hydrocarbons (PAHs) from benthic adult bivalves could result in phototoxicity to their pelagic larvae when exposed to ultraviolet light (UV). In these experiments, adult bivalves were e...

  14. COMPARISON OF IMMUNOASSAY AND GAS CHROMATOGRAPHY/MASS SPECTROMETRY FOR MEASUREMENT OF POLYCYCLIC AROMATIC HYDROCARBONS IN CONTAMINATED SOIL

    EPA Science Inventory

    Polycyclic aromatic hydrocarbons (PAHs) are frequently encountered in the environment and may pose health concerns due to their carcinogenicity. A commercial enzyme-linked immunosorbent assay (ELISA), was evaluated as a screening method for monitoring PAHs at contaminated site...

  15. CROSS-INDUCTION OF PYRENE AND PHENANTHRENE IN MYCOBACTERIUM SP. ISOLATED FROM POLYCYCLIC AROMATIC HYDROCARBON CONTAMINATED RIVER SEDIMENTS

    EPA Science Inventory

    A polycyclic aromatic hydrocarbon (PAH)-degrading culture enriched from contaminated river sediments and a Mycobacterium sp. isolated from the enrichment were tested to investigate the possible synergistic and antagonistic interactions affecting the degradation of pyrene in the p...

  16. FORMATION OF POLYCYCLIC AROMATIC HYDROCARBONS AND THEIR GROWTH TO SOOT -A REVIEW OF CHEMICAL REACTION PATHWAYS. (R824970)

    EPA Science Inventory

    The generation by combustion processes of airborne species of current health concern such as polycyclic aromatic hydrocarbons (PAH) and soot particles necessitates a detailed understanding of chemical reaction pathways responsible for their formation. The present review discus...

  17. FORMATION OF POLYCYCLIC AROMATIC HYDROCARBONS AND THEIR GROWTH TO SOOT -A REVIEW OF CHEMICAL REACTION PATHWAYS. (R824970)

    EPA Science Inventory

    The generation by combustion processes of airborne species of current health concern such as polycyclic aromatic hydrocarbons (PAH) and soot particles necessitates a detailed understanding of chemical reaction pathways responsible for their formation. The present review discus...

  18. PHOTOACTIVATED POLYCYCLIC AROMATIC HYDROCARBON TOXICITY IN MEDAKA (ORYZIAS LATIPES) EMBRYOS: RELEVANCE TO ENVIRONMENTAL RISK IN CONTAMINATED SITES

    EPA Science Inventory

    The hazard for photoactivated toxicity of polycyclic aromatic hydrocarbons (PAHs) has been clearly demonstrated; however, to our knowledge, the risk in contaminated systems has not been characterized. To address this question, a median lethal dose (LD50) for fluoranthene photoa...

  19. IMPORTANCE OF MATERNAL TRANSFER OF THE PHOTOREACTIVE POLYCYCLIC AROMATIC HYDROCARBON FLUORANTHENE FROM BENTHIC ADULT BIVALVES TO THEIR PELAGIC LARVAE

    EPA Science Inventory

    Laboratory experiments were conducted to determine if maternal transfer of polycyclic aromatic hydrocarbons (PAHs) from benthic adult bivalves could result in phototoxicity to their pelagic larvae when exposed to ultraviolet light (UV). In these experiments, adult bivalves were e...

  20. IMPORTANCE OF BLACK CARBON IN DISTRIBUTION AND BIOACCUMULATION MODELS OF POLYCYCLIC AROMATIC HYDROCARBONS IN CONTAMINATED MARINE SEDIMENTS

    EPA Science Inventory

    The roles and relative importance of nonpyrogenic organic carbon (NPOC) and black carbon (BC) as binding phases of polycyclic aromatic hydrocarbons (PAHs) were assessed by their ability to estimate pore water concentrations and biological uptake in various marine sediments. Sedim...

  1. PHOTOACTIVATED POLYCYCLIC AROMATIC HYDROCARBON TOXICITY IN MEDAKA (ORYZIAS LATIPES) EMBRYOS: RELEVANCE TO ENVIRONMENTAL RISK IN CONTAMINATED SITES

    EPA Science Inventory

    The hazard for photoactivated toxicity of polycyclic aromatic hydrocarbons (PAHs) has been clearly demonstrated; however, to our knowledge, the risk in contaminated systems has not been characterized. To address this question, a median lethal dose (LD50) for fluoranthene photoa...

  2. Polycyclic Aromatic Hydrocarbons in Fine Particulate Matter Emitted from Burning Kerosene, Liquid Petroleum Gas, and Wood Fuels in Household Cookstoves

    EPA Science Inventory

    This study measured polycyclic aromatic hydrocarbon (PAH) composition in particulate matter emissions from residential cookstoves. A variety of fuel and cookstove combinations were examined, including: (i) liquid petroleum gas (LPG), (ii) kerosene in a wick stove, (iii) wood (10%...

  3. COMPARISON OF IMMUNOASSAY AND GAS CHROMATOGRAPHY/MASS SPECTROMETRY FOR MEASUREMENT OF POLYCYCLIC AROMATIC HYDROCARBONS IN CONTAMINATED SOIL

    EPA Science Inventory

    Polycyclic aromatic hydrocarbons (PAHs) are frequently encountered in the environment and may pose health concerns due to their carcinogenicity. A commercial enzyme-linked immunosorbent assay (ELISA), was evaluated as a screening method for monitoring PAHs at contaminated site...

  4. CROSS-INDUCTION OF PYRENE AND PHENANTHRENE IN MYCOBACTERIUM SP. ISOLATED FROM POLYCYCLIC AROMATIC HYDROCARBON CONTAMINATED RIVER SEDIMENTS

    EPA Science Inventory

    A polycyclic aromatic hydrocarbon (PAH)-degrading culture enriched from contaminated river sediments and a Mycobacterium sp. isolated from the enrichment were tested to investigate the possible synergistic and antagonistic interactions affecting the degradation of pyrene in the p...

  5. Δg: The new aromaticity index based on g-factor calculation applied for polycyclic benzene rings

    NASA Astrophysics Data System (ADS)

    Ucun, Fatih; Tokatlı, Ahmet

    2015-02-01

    In this work, the aromaticity of polycyclic benzene rings was evaluated by the calculation of g-factor for a hydrogen placed perpendicularly at geometrical center of related ring plane at a distance of 1.2 Å. The results have compared with the other commonly used aromatic indices, such as HOMA, NICSs, PDI, FLU, MCI, CTED and, generally been found to be in agreement with them. So, it was proposed that the calculation of the average g-factor as Δg could be applied to study the aromaticity of polycyclic benzene rings without any restriction in the number of benzene rings as a new magnetic-based aromaticity index.

  6. Measurement of total polycyclic aromatic hydrocarbon concentrations in sediments and toxic units used for estimating risk to benthic invertebrates at manufactured gas plant sites.

    PubMed

    Hawthorne, Steven B; Miller, David J; Kreitinger, Joseph P

    2006-01-01

    The U.S. Environmental Protection Agency's (U.S. EPA) narcosis model requires the measurement of 18 parent and 16 groups of alkyl polycyclic aromatic hydrocarbons (PAHs) (so-called 34 PAHs) in sediments to calculate the number of PAH toxic units (TU) available to benthic organisms. If data for the 34 PAHs are not available, the U.S. EPA proposes estimating the risk by multiplying the TU for 13 parent PAHs by 11.5 (95% confidence interval) based on data from 488 sediments. This estimate is overly conservative for PAHs from pyrogenic manufactured gas plant (MGP) processes based on the analysis of 45 sediments from six sites. Parent PAHs contributed approximately 40% of the total concentrations and TU for MGP sediments. In contrast, parent PAHs from diesel fuel and petroleum crude oil contributed only 2 and 1%, respectively, of the PAH concentrations and TU, compared to approximately 98 to 99% contributed by the alkyl PAHs. Statistical comparison of the TU based on the measured 34 alkyl and parent PAHs and those based on only 13 parent PAHs demonstrated that a factor of 4.2 (rather than 11.5) is sufficient to estimate total TU within a 95% confidence level for MGP sites. Similarly, measurement of parent PAHs is sufficient to accurately estimate the total 34 alkyl and parent PAH concentrations for MGP-impacted sediments.

  7. [Effects of smoking on the concentrations of urinary 10 metabolites of polycyclic aromatic hydrocarbons in coke oven workers].

    PubMed

    He, Yun-feng; Zhang, Wang-zhen; Kuang, Dan; Deng, Hua-xin; Li, Xiao-hai; Lin, Da-feng; Deng, Qi-fei; Huang, Kun; Wu, Tang-chun

    2012-12-01

    To explore the effects of smoking on urinary 10 metabolites of polycyclic aromatic hydrocarbons (PAHs) in the coke oven workers. Occupational health examination was performed on 1401 coke oven workers in one coking plant, their urine were collected respectively. The concentrations of the ten monohydroxy polycyclic aromatic hydrocarbons in urine were detected by gas chromatography/mass spectrometry. The 1401 workers were divided into four groups, namely control, adjunct workplaces, bottom and side, top group according to their workplaces and the different concentrations of PAHs in the environment. The concentrations of the ten monohydroxy polycyclic aromatic hydrocarbons between smokers and nonsmokers in each workplace group were compared using analysis of covariance, respectively. The levels of concentrations of the sixteen polycyclic aromatic hydrocarbons we detected at control were significantly higher than those at other areas (P < 0.05). Comparing the ten monohydroxy polycyclic aromatic hydrocarbons levels between smokers and nonsmokers, the levels of 1-hydroxynaphthalene and 2-hydroxynaphthalene among smokers were higher than nonsmokers with statistically significance in control, adjunct workplaces, bottom and side and top groups (P < 0.05). However, the levels of 1-hydroxypyrene had no statistically significant differences between the four areas. Urinary 1-hydroxynaphthalene and 2-hydroxynaphthalene may be used as biomarkers for the impact of smoking on monohydroxy polycyclic aromatic hydrocarbons in the coke oven workers.

  8. Renal cancer risk and occupational exposure to polycyclic aromatic hydrocarbons and plastics

    PubMed Central

    Karami, Sara; Boffetta, Paolo; Brennan, Paul; Stewart, Patricia A.; Zaridze, David; Matveev, Vsevolod; Janout, Vladimir; Kollarova, Helena; Bencko, Vladimir; Navratilova, Marie; Szeszenia-Dabrowska, Neonila; Mates, Dana; Gromiec, Jan P.; Sobotka, Roman; Chow, Wong-Ho; Rothman, Nathaniel; Moore, Lee E.

    2011-01-01

    Objective To investigate whether occupational exposure to polycyclic aromatic hydrocarbons and certain plastic monomers increased renal cell carcinomas (RCC) risk. Methods Unconditional logistic regression was used to calculate RCC risk in relation to exposure. Results No association between RCC risk and having ever been occupationally exposed to any polycyclic aromatic hydrocarbons or plastics was observed. Duration of exposure and average exposure also showed no association with risk. Suggestive positive associations between RCC risk and cumulative exposure to styrene (P-trend = 0.02) and acrylonitrile (P-trend = 0.06) were found. Cumulative exposure to petroleum/gasoline engine emissions was inversely associated with risk (P-trend = 0.02). Conclusions Results indicate a possible association between occupational styrene and acrylonitrile exposure and RCC risk. Additional studies are needed to replicate findings, as this is the first time these associations have been reported and they may be due to chance. PMID:21270648

  9. Characterization of subsurface polycyclic aromatic hydrocarbons at the Deepwater Horizon site

    NASA Astrophysics Data System (ADS)

    Diercks, Arne-R.; Highsmith, Raymond C.; Asper, Vernon L.; Joung, DongJoo; Zhou, Zhengzhen; Guo, Laodong; Shiller, Alan M.; Joye, Samantha B.; Teske, Andreas P.; Guinasso, Norman; Wade, Terry L.; Lohrenz, Steven E.

    2010-10-01

    Here, we report the initial observations of distributions of polycyclic aromatic hydrocarbons (PAH) in subsurface waters near the Deepwater Horizon oil well site (also referred to as the Macondo, Mississippi Canyon Block 252 or MC252 well). Profiles of in situ fluorescence and beam attenuation conducted during 9-16 May 2010 were characterized by distinct peaks at depths greater than 1000 m, with highest intensities close to the wellhead and decreasing intensities with increasing distance from the wellhead. Gas chromatography/mass spectrometry (GC/MS) analyses of water samples coinciding with the deep fluorescence and beam attenuation anomalies confirmed the presence of polycyclic aromatic hydrocarbons (PAH) at concentrations reaching 189 μg L-1 (ppb). Subsurface exposure to PAH at levels considered to be toxic to marine organisms would have occurred in discrete depth layers between 1000 and 1400 m in the region southwest of the wellhead site and extending at least as far as 13 km.

  10. PRESSURE EFFECTS IN POLYCYCLIC AROMATIC NITROGENATED HETEROCYCLES (PANHs): DIAGNOSTIC QUALITIES AND COSMOBAROMETRY POTENTIAL

    SciTech Connect

    Montgomery, Wren; Sephton, Mark A.

    2016-03-01

    The influence of polycyclic aromatic nitrogen heterocycles (PANHs), which have been suggested as contributors to the interstellar IR emission bands, on interstellar emission features is difficult to constrain because their infrared characteristics are strongly similar to those for polycyclic aromatic hydrocarbons (PAHs). One possible solution is to seek a means of visualizing the presence of PANHs that provides information that is distinct from that for PAHs. Although PANHs and PAHs have similar infrared characteristics in many settings, this relationship may not be universally maintained. We have used in situ high-pressure synchrotron-source Fourier transform infrared spectroscopy to determine that the responses of two representative molecules, acridine and anthracene, differ at high pressures (>ca. 1 GPa). Because there are a number of high-pressure environments that can be remotely observed by infrared spectroscopy, they represent a potential to glimpse the distribution of PANHs across the cosmos.

  11. Pressure Effects in Polycyclic Aromatic Nitrogenated Heterocycles (PANHs): Diagnostic Qualities and Cosmobarometry Potential

    NASA Astrophysics Data System (ADS)

    Montgomery, Wren; Sephton, Mark A.

    2016-03-01

    The influence of polycyclic aromatic nitrogen heterocycles (PANHs), which have been suggested as contributors to the interstellar IR emission bands, on interstellar emission features is difficult to constrain because their infrared characteristics are strongly similar to those for polycyclic aromatic hydrocarbons (PAHs). One possible solution is to seek a means of visualizing the presence of PANHs that provides information that is distinct from that for PAHs. Although PANHs and PAHs have similar infrared characteristics in many settings, this relationship may not be universally maintained. We have used in situ high-pressure synchrotron-source Fourier transform infrared spectroscopy to determine that the responses of two representative molecules, acridine and anthracene, differ at high pressures (>ca. 1 GPa). Because there are a number of high-pressure environments that can be remotely observed by infrared spectroscopy, they represent a potential to glimpse the distribution of PANHs across the cosmos.

  12. Soot formation from polycyclic aromatics. Technical progress report, September 1, 1980-February 28, 1981

    SciTech Connect

    Frenklach, M.

    1981-03-01

    The initial phase of this study has been focused on determining the accuracy of the absolute values of soot conversion and the reliability of the experimental techniques employed to determine soot formation from polycyclic aromatics in various shock tube experiments. The LSU experimental results have demonstrated consistency between the present observations and results reported by other research groups, thus eliminating the controversies suggested by a number of researchers. Analysis of the preliminary experimental data has resulted in the postulation of a new conceptual mechanistic model for soot formation from polycyclic aromatics. Preliminary analysis using the model offers an explanation of various experimental trends. Additional work with this conceptual model may subsequently lead to a more systematic approach for determination and classification of the soot formation data.

  13. Factors affecting elimination of polycyclic aromatic hydrocarbons from traditional smoked common carp meat

    NASA Astrophysics Data System (ADS)

    Babić, J.; Vidaković, S.; Škaljac, S.; Kartalović, B.; Ljubojević, D.; Ćirković, M.; Teodorović, V.

    2017-09-01

    Smoking techniques have been progressively improved and different procedures have been developed in different regions for treating fish. In these times, the technology is mainly used for enrichment of fish with specific taste and odour, to extend the shelf-life of these perishable products and appearance required widely on the market. A lot of chemical contaminants such as polycyclic aromatic hydrocarbons (PAHs) are formed during the combustion of fuel in the smoking process. PAHs are a group of compounds that have been the subject of great concern in the recent years due to their toxic, mutagenic and/or carcinogenic potentials to humans. These fact can have a significant impact on the acceptance of these products by consumers. In this review article, the objective is to describe factors affecting elimination of polycyclic aromatic hydrocarbons from traditional smoked common carp meat.

  14. NMR solution structures of adducts derived from the binding of polycyclic aromatic diol epoxides to DNA

    SciTech Connect

    Cosman, M.; Patel, D.J.; Hingerty, B.E.; Amin, S.; Broyde, S.; Geacintov, N.E.

    1995-12-31

    Site-specifically modified oligonucleotides were derived from the reactions of stereoisomeric polycyclic aromatic diol epoxide metabolite model compounds with oligonucleotides of defined base composition and sequence. The NMR solution structures of ten different adducts studied so far are briefly described, and it is shown that stereochemical factors and the nature of the oligonucleotide context of the complementary strands, exert a powerful influence on the conformational features of these adducts.

  15. Geochemistry of polycyclic aromatic hydrocarbons in Columbia River and Washington coastal sediments

    SciTech Connect

    Prahl, F.G.

    1982-01-20

    A field investigation was conducted to determine the origins, dispersal pathways and fates of polycyclic aromatic hydrocarbons (PAH) in a river-influenced coastal marine environment. Complete PAH characterizations were combined with analyses of aliphatic hydrocarbons, organic carbon and nitrogen, lignin, lead-210 and several other parameters to clarify the geochemistry of this class of compounds in the Columbia River basin and the southern Washington continental shelf and slope. 94 references, 18 figures, 24 tables.

  16. Shape-persistent elliptic macrocycles composed of polycyclic aromatic hydrocarbons: synthesis and photophysical properties.

    PubMed

    Liu, Wen-Jun; Zhou, Yan; Zhou, Qi-Feng; Ma, Yuguo; Pei, Jian

    2008-06-05

    Bimolecular coupling/unimolecular cyclization strategies, including McMurry- and Glaser-type homocoupling reactions, were utilized to synthesize two shape-persistent elliptic macrocycles, which consist of polycyclic aromatic hydrocarbon units. The identity and purity of both macrocycles MC1 and MC2 were verified by 1H and 13C NMR, elemental analysis, as well as MALDI-TOF MS. The photophysical properties of MC1 and MC2 in dilute solution were also investigated.

  17. Synergism in the desorption of polycyclic aromatic hydrocarbons from soil models by mixed surfactant solutions.

    PubMed

    Sales, Pablo S; Fernández, Mariana A

    2016-05-01

    This study investigates the effect of a mixed surfactant system on the desorption of polycyclic aromatic hydrocarbons (PAHs) from soil model systems. The interaction of a non-ionic surfactant, Tween 80, and an anionic one, sodium laurate, forming mixed micelles, produces several beneficial effects, including reduction of adsorption onto solid of the non-ionic surfactant, decrease in the precipitation of the fatty acid salt, and synergism to solubilize PAHs from solids compared with individual surfactants.

  18. Degradation of Polycyclic Aromatic Hydrocarbons by a Newly Discovered Enteric Bacterium, Leclercia adecarboxylata

    PubMed Central

    Sarma, Priyangshu Manab; Bhattacharya, Dhruva; Krishnan, S.; Lal, Banwari

    2004-01-01

    A bacterial strain, PS4040, capable of degrading polycyclic aromatic hydrocarbons for use as the sole carbon source was isolated from oily-sludge-contaminated soil. The 16S rRNA gene showed 98.8% homology to that of Leclercia adecarboxylata. Comparative molecular typing with the clinical strain of L. adecarboxylata revealed that there were few comigrating and few distinct amplimers among them. PMID:15128584

  19. Phototoxicity of non-carcinogenic polycyclic aromatic hydrocarbons in aquatic organisms

    SciTech Connect

    Kagan, J.; Kagan, E.D.; Kagan, I.A.; Kagan, P.A.; Quigley, S.

    1985-01-01

    Anthracene, fluoranthene, and pyrene are phototoxic in Daphnia magna, Artemia salina, first instar larvae of Aedes aegypti, late embryonic forms of Rana pipiens, and fish (Pimephales promelas). Since polycyclic aromatic hydrocarbons are generated in the combustion processes held responsible for the damages of acid rain, and they are introduced into the environment through other means as well, the high phototoxicity of the major pollutants, which are not carcinogenic, suggests that greater attention must be given to their environmental significance.

  20. [Distribution of various polycyclic aromatic hydrocarbons in reservoir water of Estonia].

    PubMed

    Veldre, I A; Itra, A R; Paal'me, L P; Urbas, E R

    1985-01-01

    The paper presents experimental data on different polycyclic aromatic hydrocarbons (PAH) in water, bottom sediments and algae as well as evidence available in literature on their content in exhausts of automobiles, oil shale industry and power station. Attempts are made to reveal differences in sources of the environment pollution with allowance for different PAH/benzo(a)pyrene percentage ratio, but as the PAH ratios are relatively similar in different pollution sources this attempt was a failure.

  1. Toxicity of aromatic polycyclic hydrocarbons. (Latest citations from the Life Sciences Collection database). Published Search

    SciTech Connect

    1997-04-01

    The bibliography contains citations concerning the toxicity and biochemical effects of aromatic polycyclic hydrocarbons. Topics include effects on metabolism and liver activity, cellular responses, binding characteristics, and the occurrence and path of the compounds in food chains. Bioaccumulation studies in specific areas, and isolation and detection techniques are also considered. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  2. Toxicity of polycyclic aromatic hydrocarbons. (Latest citations from Pollution abstracts). Published Search

    SciTech Connect

    Not Available

    1994-06-01

    The bibliography contains citations concerning the toxicity and biochemical effects of aromatic polycyclic hydrocarbons. Topics include effects on metabolism and liver activity, cellular responses, binding characteristics, and the occurrence and path of the compounds in food chains. Bioaccumulation studies in specific areas, and isolation and detection techniques are also considered. (Contains a minimum of 242 citations and includes a subject term index and title list.)

  3. Toxicity of aromatic polycyclic hydrocarbons. (Latest citations from the Life Sciences Collection database). Published Search

    SciTech Connect

    1995-12-01

    The bibliography contains citations concerning the toxicity and biochemical effects of aromatic polycyclic hydrocarbons. Topics include effects on metabolism and liver activity, cellular responses, binding characteristics, and the occurrence and path of the compounds in food chains. Bioaccumulation studies in specific areas, and isolation and detection techniques are also considered. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  4. Fingerprint of polycyclic aromatic hydrocarbons in two populations of southern sea lions (Otaria flavescens).

    PubMed

    Marsili, L; Fossi, M C; Casini, S; Savelli, C; Jimenez, B; Junin, M; Castello, H

    1997-02-01

    The fingerprint of 14 polycyclic aromatic hydrocarbons (PAHs) was investigated in biopsy, fur, blood, liver and faeces of live and dead specimens of two Argentinian population of southern sea lion (Otaria flavescens). One colony lives in Mar del Plata harbour which is particularly polluted with petroleum, the second (control) colony lives at Punta Bermeja (Patagonia). The highest concentrations of the five carcinogenic PAHs were found in the Mar del Plata sea lions.

  5. The possible existence of interstellar Polycyclic Aromatic Hydrocarbons (PAHs) in collected interplanetary dust particles

    NASA Technical Reports Server (NTRS)

    Sandford, S. A.

    1986-01-01

    Extraterrestrial dust particles which are 3 to 50 microns in size are routinely collected in the stratosphere and are now available for general laboratory study. These grains represent true Interplanetary Dust Particles (IDPs). Issues associated with the carbon containing components of IDPs which occur in a variety of physical forms, including amorphous mantles and matrix materials, are addressed. The observed properties of the hydrocarbon phase in IDPs are compared with those expected for polycyclic aromatic hydrocarbons (PAHs).

  6. Biosurfactant production by a soil Pseudomonas strain growing on polycyclic aromatic hydrocarbons

    SciTech Connect

    Deziel, E.; Paquette, G.; Villemur, R.; Lepine, F.

    1996-06-01

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants occurring mostly as a result of fossil fuel combustion and as by-products of industrial activities. The bioremediation of soils contaminated with PAHs is limited by the poor availability of dyrophobic contaminants to microorganisms. Surfactants can help. Recent studies indicate that addition of surfactants can enhance hydrocarbon biodegradation. This study examines whether production of surfactants by PAH-metabolizing microorganisms is part of their strategy for growing on such poorly available substrates.

  7. Emission characteristics of polycyclic aromatic hydrocarbons and nitro-polycyclic aromatic hydrocarbons from diesel trucks based on on-road measurements

    NASA Astrophysics Data System (ADS)

    Cao, Xinyue; Hao, Xuewei; Shen, Xianbao; Jiang, Xi; Wu, Bobo; Yao, Zhiliang

    2017-01-01

    Polycyclic aromatic hydrocarbon (PAH) and nitro-polycyclic aromatic hydrocarbon (NPAH) emissions from 18 diesel trucks of different sizes and with different emission standards were tested in Beijing using a portable emission measurement system (PEMS). Both the gaseous- and particulate-phase PAHs and NPAHs were quantified by high-performance liquid chromatography (HPLC) in the laboratory. The emission factors (EFs) of the total PAHs from light-duty diesel trucks (LDDTs), medium-duty diesel trucks (MDDTs) and heavy-duty diesel trucks (HDDTs) were 82229.11 ± 41906.06, 52867.43 ± 18946.47 and 93837.35 ± 32193.14 μg/km, respectively, much higher than the respective values of total NPAHs from their counterpart vehicles. The gaseous phase had an important contribution to the total PAHs and NPAHs, with a share rate of approximately 69% and 97% on average, respectively. The driving cycle had important impacts on the emissions of PAHs and NPAHs, especially for LDDTs and HDDTs. Higher emissions of PAHs and NPAHs were detected on non-highway roads compared to that on highways for these two types of vehicles. Compared to the results of different studies, the difference in the EFs of PAHs and NPAHs can reach several orders of magnitudes, which would introduce errors in the development of an emission inventory of PAHs and NPAHs.

  8. Distribution and origins of polycyclic aromatic hydrocarbons (PAHs) in riverine, estuarine, and marine sediments in Thailand.

    PubMed

    Boonyatumanond, Ruchaya; Wattayakorn, Gullaya; Togo, Ayako; Takada, Hideshige

    2006-08-01

    To assess the status of polycyclic aromatic hydrocarbon (PAH) contamination in coastal and riverine environments in Thailand, we collected 42 surface sediment samples from canals, a river, an estuary, and coastal areas in Thailand in 2003 and analyzed them for PAHs with 3-7 benzene rings by gas chromatography-mass spectrometry (GC-MS). The total concentration of PAHs ranged from 6 to 8399 ng/g dry weight. The average total PAH concentrations were 2290+/-2556 ng/g dry weight (n=8) in canals, 263+/-174 (n=11) in the river, 179+/-222 (n=9) in the estuary, and 50+/-56 (n=14) in coastal areas. Comparison of the concentration range with a worldwide survey of sedimentary PAH concentrations ranked PAH contamination in Thai sediments as low to moderate. The ratio of the sum of methylphenanthrenes to phenanthrene (MP/P ratio) allows discrimination of PAH sources between petrogenic (>2) and pyrogenic (<0.5) origins. Sediments from urban canals in Bangkok showed the highest PAH concentrations and petrogenic signatures (MP/P=1.84+/-0.98 [n=6] in canal sediments) with abundant alkylated PAHs, indicating major sources of petrogenic PAHs in the city. To identify the sources of the petrogenic inputs in Thailand, we analyzed triterpanes, biomarkers of petroleum pollution, in the sediment samples and in potential source materials. Hopane profiles were remarkably uniform throughout the nation, suggesting a diffuse single source (e.g. automobiles). Molecular profiles of hopanes and PAHs in sediments from the urban canals were similar to those in street dust, indicating that street dust is one of the major sources of petrogenic PAHs in the urban area. On the other hand, low levels of PAHs (approximately 50 ng/g) with a pyrogenic signature (MP/P ratio approximately 0.5) were widely recorded in remote areas of the coast and the Chao Phraya River. These pyrogenic PAHs may be atmospherically transported throughout the nation. Middle and lower reaches of the Chao Phraya River, the river

  9. [Halogenated polycyclic aromatic hydrocarbons in surface sediments of Maozhou River, Shenzhen].

    PubMed

    Sun, Jian-Lin; Ni, Hong-Gang; Ding, Chao; Zeng, Hui

    2012-09-01

    Surface sediments collected from the Maozhou River watershed in Shenzhen were analyzed for the concentration levels and spatial distribution characteristics of halogenated polycyclic aromatic hydrocarbons (HPAHs) using GC-MS. Total concentrations of three chlorinated polycyclic aromatic hydrocarbons (ClPAHs) and six brominated polycyclic aromatic hydrocarbons (BrPAHs) of concern ranged from 3.00 to 301 ng x g(-1) and 7.52 to 285 ng x g(-1), respectively. Source appointments indicated that the HPAHs in these surface sediments were mainly derived from waste incineration, fossil fuel combustion, vehicle emission, and burning of crop straw, accounting for 40%, 20.5% 11.9%, and 11.7% of the total loading, respectively. Additionally, the toxic equivalency quotients (TEQ) of total ClPAHs and BrPAHs ranged from 7.95 to 38.1 pg x g(-1) and 38.1 to 105 pg x g(-1) respectively. Finally, the relationships between the HPAHs levels and different land use types were examined. Results indicated that the levels of HPAHs in surface sediments showed a decreasing trend after the first increase to the peak with the density of industrial land, but inversely proportional to the density of agricultural land.

  10. Processing of atmospheric polycyclic aromatic hydrocarbons by fog in an urban environment.

    PubMed

    Ehrenhauser, Franz S; Khadapkar, Kalindi; Wang, Youliang; Hutchings, James W; Delhomme, Olivier; Kommalapati, Raghava R; Herckes, Pierre; Wornat, Mary J; Valsaraj, Kalliat T

    2012-10-26

    Polycyclic aromatic hydrocarbons (PAH) are ubiquitous pollutants in the atmosphere, predominantly known for their toxicity. Although there has been substantial work on the atmospheric degradation of PAH, little is known about how the presence of atmospheric droplets (e.g., a fog cloud) affects the fate of PAH. In order to assess the processing of PAH and their corresponding oxidation products during a fog event, two field-sampling campaigns in Fresno, CA and Davis, CA were conducted. The simultaneous evaluation of concentrations of the PAH and oxygenated polycyclic aromatic compounds (OPAC) in the gas phase, particulate matter and fog water droplets before, during and after fog allows for the characterization of transformative and transport processes in a fog cloud. By tracking the ratio of OPAC to PAH in the individual atmospheric phases, two major polycyclic aromatic compounds-processing pathways can be identified: (i) the dissolution of OPAC from particulate matter and (ii) the uptake and oxidation of PAH in the fog water droplets. Wet deposition steadily decreases the pollutant concentration in the fog cloud droplets during a fog event; however, uptake and concentration via evaporative water loss upon the dissipation of a fog cloud cause an increase in the atmospheric pollutant concentration.

  11. Assessment of the bioavailability and phytotoxicity of sediment spiked with polycyclic aromatic hydrocarbons.

    PubMed

    Rončević, Srđan; Spasojević, Jelena; Maletić, Snežana; Jazić, Jelena Molnar; Isakovski, Marijana Kragulj; Agbaba, Jasmina; Grgić, Marko; Dalmacija, Božo

    2016-02-01

    Large amounts of sediment are dredged globally every year. This sediment is often contaminated with low concentrations of metals, polycyclic aromatic hydrocarbons, pesticides and other organic pollutants. Some of this sediment is disposed of on land, creating a need for risk assessment of the sediment disposal method, to minimize the degradation of environmental quality and prevent risks to human health. Evaluating the available fractions of certain polycyclic aromatic hydrocarbons is very important, as in the presence of various organisms, they are believed to be easily subject to the processes of bioaccumulation, biosorption and transformation. In order to determine the applicability of applying these methods for the evaluation of pollutant bioavailability in sediments, the desorption kinetics from the sediment of various polycyclic aromatic hydrocarbons in the presence of Tenax and XAD4 were examined over the course of 216 h. Changes in the PAH concentrations in dredged sediments using five different seed plants during a short time of period (10 days) were also followed. Using chemical extraction techniques with Tenax and XAD4, a time of around 24 h is enough to achieve equilibrium for all four PAHs. Results showed good agreement between the seed accumulation and PAH extraction methods with both agents. If we compare the two extraction techniques, XAD4 gave better results for phenanthrene, pyrene and benzo(a)pyrene, and Tenax gave better results for chrysene.

  12. Polycyclic aromatic hydrocarbons and heavy metals in the Cispata Bay, Colombia: A marine tropical ecosystem.

    PubMed

    Burgos-Núñez, Saudith; Navarro-Frómeta, Amado; Marrugo-Negrete, José; Enamorado-Montes, Germán; Urango-Cárdenas, Iván

    2017-07-15

    The concentrations of polycyclic aromatic hydrocarbons and heavy metals were evaluated in shallow sediments, water, fish and seabird samples from the Cispata Bay, Colombia. The heavy metals concentrations in the sediment was in the following order: Cu>Pb>Hg>Cd. The heavy metal concentration was different (p<0.05) in juvenile and adult birds. High concentrations of mercury were registered in the seabird (10.19±4.99mgkg(-1)) and fish (0.67μgg(-1)) samples. The total concentration of polycyclic aromatic hydrocarbons ranged from 7.0-41ngg(-1) in sediment, 0.03-0.34ngmL(-1) in water samples, 53.24ngg(-1) in fish, and 66ngg(-1) in seabirds. The high concentrations of heavy metals in seabirds may be explained by their feeding habits. The presence of polycyclic aromatic hydrocarbons in the Cispata Bay may be due to hydrocarbon spills during oil transport at the nearby oil port. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Aromatic compound glucosides, alkyl glucoside and glucide from the fruit of anise.

    PubMed

    Fujimatu, Eiko; Ishikawa, Toru; Kitajima, Junichi

    2003-07-01

    From the polar portion of the methanolic extract of the fruit of anise (Pimpinella anisum L.), which has been used as a spice and medicine since antiquity, four aromatic compound glucosides, an alkyl glucoside and a glucide were isolated together with 24 known compounds. The structures of the new compounds were clarified as (E)-3-hydroxyanethole beta-D-glucopyranoside, (E)-1'-(2-hydroxy-5-methoxyphenyl)propane beta-D-glucopyranoside, 3-hydroxyestragole beta-D-glucopyranoside, methyl syringate 4-O-beta-D-glucopyranoside, hexane-1,5-diol 1-O-beta-D-glucopyranoside and 1-deoxy-L-erythritol 3-O-beta-D-glucopyranoside by spectral investigation.

  14. Selective and Serial Suzuki–Miyaura Reactions of Polychlorinated Aromatics with Alkyl Pinacol Boronic Esters

    PubMed Central

    2016-01-01

    Among cross-coupling reactions, the Suzuki–Miyaura transformation stands out because of its practical advantages, including the commercial availability and low toxicity of the required reagents, mild reaction conditions, and functional group compatibility. Nevertheless, few conditions can be used to cross-couple alkyl boronic acids or esters with aryl halides, especially 2-pyridyl halides. Herein, we describe two novel Suzuki–Miyaura protocols that enable selective conversion of polychlorinated aromatics, with a focus on reactions to convert 2,6-dichloropyridines to 2-chloro-6-alkylpyridines or 2-aryl-6-alkylpyridines. PMID:27537216

  15. Combined effects of prenatal polycyclic aromatic hydrocarbons and material hardship on child IQ.

    PubMed

    Vishnevetsky, Julia; Tang, Deliang; Chang, Hsin-Wen; Roen, Emily L; Wang, Ya; Rauh, Virginia; Wang, Shuang; Miller, Rachel L; Herbstman, Julie; Perera, Frederica P

    2015-01-01

    Polycyclic aromatic hydrocarbons are common carcinogenic and neurotoxic urban air pollutants. Toxic exposures, including air pollution, are disproportionately high in communities of color and frequently co-occur with chronic economic deprivation. We examined whether the association between child IQ and prenatal exposure to polycyclic aromatic hydrocarbons differed between groups of children whose mothers reported high vs. low material hardship during their pregnancy and through child age 5. We tested statistical interactions between hardships and polycyclic aromatic hydrocarbons, as measured by DNA adducts in cord blood, to determine whether material hardship exacerbated the association between adducts and IQ scores. Prospective cohort. Participants were recruited from 1998 to 2006 and followed from gestation through age 7 years. Urban community (New York City) A community-based sample of 276 minority urban youth EXPOSURE MEASURE: Polycyclic aromatic hydrocarbon-DNA adducts in cord blood as an individual biomarker of prenatal polycyclic aromatic hydrocarbon exposure. Maternal material hardship self-reported prenatally and at multiple timepoints through early childhood. Child IQ at 7 years assessed using the Wechsler Intelligence Scale for Children. Significant inverse effects of high cord PAH-DNA adducts on full scale IQ, perceptual reasoning and working memory scores were observed in the groups whose mothers reported a high level of material hardship during pregnancy or recurring high hardship into the child's early years, and not in those without reported high hardship. Significant interactions were observed between high cord adducts and prenatal hardship on working memory scores (β = -8.07, 95% CI (-14.48, -1.66)) and between high cord adducts and recurrent material hardship (β = -9.82, 95% CI (-16.22, -3.42)). The findings add to other evidence that socioeconomic disadvantage can increase the adverse effects of toxic physical "stressors" like air pollutants

  16. Fingerprints of polycyclic aromatic hydrocarbons (PAHs) in infrared absorption spectroscopy.

    PubMed

    Tommasini, Matteo; Lucotti, Andrea; Alfè, Michela; Ciajolo, Anna; Zerbi, Giuseppe

    2016-01-05

    We have analyzed a set of 51 PAHs whose structures have been hypothesized from mass spectrometry data collected on samples extracted from carbon particles of combustion origin. We have obtained relationships between infrared absorption signals in the fingerprint region (mid-IR) and the chemical structures of PAHs, thus proving the potential of IR spectroscopy for the characterization of the molecular structure of aromatic combustion products. The results obtained here for the spectroscopic characterization of PAHs can be also of interest in Materials Science and Astrophysics.

  17. THE EFFECTS OF EQUIVALENCE RATIO ON THE FORMATION OF POLYCYCLIC AROMATIC HYDROCARBONS AND SOOT IN PREMIXED ETHANE FLAMES. (R825412)

    EPA Science Inventory

    Abstract

    The formation of polycyclic aromatic hydrocarbons (PAH) and soot has been investigated in atmospheric-pressure, laminar, ethane/oxygen/argon premixed flames as a function of mixture equivalence ratio. Mole fraction profiles of major products, trace aromatics, ...

  18. THE EFFECTS OF EQUIVALENCE RATIO ON THE FORMATION OF POLYCYCLIC AROMATIC HYDROCARBONS AND SOOT IN PREMIXED ETHANE FLAMES. (R825412)

    EPA Science Inventory

    Abstract

    The formation of polycyclic aromatic hydrocarbons (PAH) and soot has been investigated in atmospheric-pressure, laminar, ethane/oxygen/argon premixed flames as a function of mixture equivalence ratio. Mole fraction profiles of major products, trace aromatics, ...

  19. (234)Th as a tracer of vertical transport of polycyclic aromatic hydrocarbons in the northern Gulf of Mexico.

    PubMed

    Adhikari, Puspa L; Maiti, Kanchan; Bosu, Somiddho; Jones, Patrick R

    2016-06-15

    Particle-mediated vertical flux of polycyclic aromatic hydrocarbons (PAHs) plays an important role in their removal from upper oceans and sets a limit on the amount delivered to the deep-sea sediments. In this study, we applied a one-dimensional steady-state (234)Th scavenging model to estimate vertical flux of PAHs in the northern Gulf of Mexico and compared them with sediment trap based flux estimates. The (234)Th-based ∑PAH43 fluxes were 6.7±1.0μgm(-2)d(-1) and 3.7±0.6μgm(-2)d(-1) while sediment trap-based fluxes were 4.0±0.6μgm(-2)d(-1) and 4.5±0.7μgm(-2)d(-1) at 150m and 250m, respectively. Alkylated homologues contributed to 80% of the total PAH fluxes which is in contrary to other regions where combustion derived parent PAHs dominate the fluxes. The results indicate that the (238)U-(234)Th disequilibria can be an effective tracer of particulate PAH fluxes in upper mesopelagic zones and can provide flux estimates with high spatial coverage needed to quantify their long term fate and transport in the marine systems.

  20. Identification and quantification of biomarkers and polycyclic aromatic hydrocarbons (PAHs) in an aged mixed contaminated site: from source to soil.

    PubMed

    Kao, Nien-Hsin; Su, Ming-Chien; Fan, Jheng-Rong; Chung, Ying-Yung

    2015-05-01

    The sources of the spill and the contaminated soils of an aged oil spill contaminated site with unknown mixed pollutants were investigated by using a set of developed forensic chemical procedures which include analysis of oil products, site investigation, gas chromatography/mass spectrometry (GC/MS) screening, biomarker identification, and finally, the confirmation of pollutants. Adamantanes (17 compounds), 10 bicyclic sesquiterpanes, 6 newly detected compounds, 16 polycyclic aromatic hydrocarbons, and 10 alkylated naphthalenes compounds in several gasoline, diesel oil samples, and contaminated soil samples were examined and quantified. GC/MS method, retention indices, relative response factors, and diagnostic ratio were used to identify and quantify pollutant compounds. The study revealed the key factors for distinguishing among gasoline and diesel oil products in the market, created a new set of retention indices for 10 bicyclic sesquiterpane compounds, and discovered 6 quantifiable compounds in analysis of fresh oil products. The suggested diagnostic ratios for BSs and the new compounds in the analysis of the biomarker show the differences among diesel products, link between the source of pollutants with contaminated soil, and the recognition of the signs of an aged spill, and the indications of weathering effects.

  1. Partitioning of polycyclic aromatic hydrocarbons between water and particles compared to bioaccumulation in mussels: a harbour case.

    PubMed

    Hellou, Jocelyne; Steller, Sean; Leonard, Jim; Langille, Morgan A; Tremblay, Diane

    2005-03-01

    Water and particles from three sites located in Halifax Harbour, near and further away from combined municipal sewage effluents (CMSE) were analysed for parental and alkylated polycyclic aromatic hydrocarbons (par and alkPAH). Bioavailability of PAH was compared for inter-tidal mussels collected at the same sites in April and November. The PAH fingerprint determined over 9 sampling times covering a period of 19 months differed more between phases (water and particles) and seasons, than between sites. In the spring, more alkPAH associated with diesel and gasoline were detected in the soluble phase, along with more bioaccumulation of alkPAH in inter-tidal mussels. A broader number of parPAH were detected in mussels collected in the fall. The mean sum of dissolved alkPAH concentrations was higher in water at the site closer to raw CMSE than at the other two sites and particles of that site. However, lowest bioconcentration factors (BCF) were determined in mussels of this more contaminated site. Similar biota-particle accumulation factors (BPAF) were determined for parPAH in mussels from the three sites, all lower than the BCF of alkPAH. The study indicates that sewage treatment plants will reduce the amount of parPAH especially larger than fluoranthene and pyrene from being deposited in the harbour; that alk naphthalenes and fluorenes present in water will continue to be discharged; that the disturbance of sediments can make particle-bound PAH available to mussels.

  2. Increase in polycyclic aromatic hydrocarbon (PAH) emissions due to briquetting: A challenge to the coal briquetting policy.

    PubMed

    Chen, Yingjun; Zhi, Guorui; Feng, Yanli; Chongguo Tian; Bi, Xinhui; Li, Jun; Zhang, Gan

    2015-09-01

    Both China and UNEP recommend replacing raw coal chunks with coal briquettes in household sector as clean coal technology (CCT), which has been confirmed by the decreased emissions of particulate matter and black carbon. However, the clean effect has never been systematically checked by other pollutants like polycyclic aromatic hydrocarbons (PAHs). In this study, 5 coals with different geological maturities were processed as both chunks and briquettes and burned in 3 typical coal stoves for the measurement of emission factors (EFs) of particle-bound PAHs. It was found that the EFs of 16 parent PAHs, 26 nitrated PAHs, 6 oxygenated PAHs, and 8 alkylated PAHs for coal briquettes were 6.90 ± 7.89, 0.04 ± 0.03, 0.65 ± 0.40, and 72.78 ± 18.23 mg/kg, respectively, which were approximately 3.1, 3.7, 1.9, and 171 times those for coal chunks, respectively. Such significant increases in PAH emissions increased human health risk and challenged the policy of CCT.

  3. Deuterium enrichment of polycyclic aromatic hydrocarbons by photochemically induced exchange with deuterium-rich cosmic ices

    NASA Technical Reports Server (NTRS)

    Sandford, S. A.; Bernstein, M. P.; Allamandola, L. J.; Gillette, J. S.; Zare, R. N.

    2000-01-01

    The polycyclic aromatic hydrocarbon (PAH) coronene (C24H12) frozen in D2O ice in a ratio of less than 1 part in 500 rapidly exchanges its hydrogen atoms with the deuterium in the ice at interstellar temperatures and pressures when exposed to ultraviolet radiation. Exchange occurs via three different chemical processes: D atom addition, D atom exchange at oxidized edge sites, and D atom exchange at aromatic edge sites. Observed exchange rates for coronene (C24H12)-D2O and d12-coronene (C24D12)-H2O isotopic substitution experiments show that PAHs in interstellar ices could easily attain the D/H levels observed in meteorites. These results may have important consequences for the abundance of deuterium observed in aromatic materials in the interstellar medium and in meteorites. These exchange mechanisms produce deuteration in characteristic molecular locations on the PAHs that may distinguish them from previously postulated processes for D enrichment of PAHs.

  4. Deuterium enrichment of polycyclic aromatic hydrocarbons by photochemically induced exchange with deuterium-rich cosmic ices

    NASA Technical Reports Server (NTRS)

    Sandford, S. A.; Bernstein, M. P.; Allamandola, L. J.; Gillette, J. S.; Zare, R. N.

    2000-01-01

    The polycyclic aromatic hydrocarbon (PAH) coronene (C24H12) frozen in D2O ice in a ratio of less than 1 part in 500 rapidly exchanges its hydrogen atoms with the deuterium in the ice at interstellar temperatures and pressures when exposed to ultraviolet radiation. Exchange occurs via three different chemical processes: D atom addition, D atom exchange at oxidized edge sites, and D atom exchange at aromatic edge sites. Observed exchange rates for coronene (C24H12)-D2O and d12-coronene (C24D12)-H2O isotopic substitution experiments show that PAHs in interstellar ices could easily attain the D/H levels observed in meteorites. These results may have important consequences for the abundance of deuterium observed in aromatic materials in the interstellar medium and in meteorites. These exchange mechanisms produce deuteration in characteristic molecular locations on the PAHs that may distinguish them from previously postulated processes for D enrichment of PAHs.

  5. Polycyclic aromatic hydrocarbons in the atmospheres of Titan and Jupiter

    NASA Technical Reports Server (NTRS)

    Sagan, Carl; Khare, B. N.; Thompson, W. R.; Mcdonald, G. D.; Wing, Michael R.; Bada, Jeffrey L.; Vo-Dinh, Tuan; Arakawa, E. T.

    1993-01-01

    PAHs are important components of the interstellar medium and carbonaceous chondrites, but have never been identified in the reducing atmospheres of the outer solar system. Incompletely characterized complex organic solids (tholins) produced by irradiating simulated Titan atmospheres reproduce well the observed UV/visible/IR optical constants of the Titan stratospheric haze. Titan tholin and a tholin generated in a crude simulation of the atmosphere of Jupiter are examined by two-step laser desorption/multiphoton ionization mass spectrometry. A range of two- to four-ring PAHs, some with one to four alkylation sites, are identified, with a net abundance of about 0.0001 g/g (grams per gram) of tholins produced. Synchronous fluorescence techniques confirm this detection. Titan tholins have proportionately more one- and two-ring PAHs than do Jupiter tholins, which in turn have more four-ring and larger PAHs. The four-ringed PAH chrysene, prominent in some discussions of interstellar grains, is found in Jupiter tholins.

  6. Polycyclic aromatic hydrocarbons in the atmospheres of Titan and Jupiter

    NASA Technical Reports Server (NTRS)

    Sagan, Carl; Khare, B. N.; Thompson, W. R.; Mcdonald, G. D.; Wing, Michael R.; Bada, Jeffrey L.; Vo-Dinh, Tuan; Arakawa, E. T.

    1993-01-01

    PAHs are important components of the interstellar medium and carbonaceous chondrites, but have never been identified in the reducing atmospheres of the outer solar system. Incompletely characterized complex organic solids (tholins) produced by irradiating simulated Titan atmospheres reproduce well the observed UV/visible/IR optical constants of the Titan stratospheric haze. Titan tholin and a tholin generated in a crude simulation of the atmosphere of Jupiter are examined by two-step laser desorption/multiphoton ionization mass spectrometry. A range of two- to four-ring PAHs, some with one to four alkylation sites, are identified, with a net abundance of about 0.0001 g/g (grams per gram) of tholins produced. Synchronous fluorescence techniques confirm this detection. Titan tholins have proportionately more one- and two-ring PAHs than do Jupiter tholins, which in turn have more four-ring and larger PAHs. The four-ringed PAH chrysene, prominent in some discussions of interstellar grains, is found in Jupiter tholins.

  7. Infrared spectra of protonated polycyclic aromatic hydrocarbon molecules: Azulene

    NASA Astrophysics Data System (ADS)

    Zhao, Dawei; Langer, Judith; Oomens, Jos; Dopfer, Otto

    2009-11-01

    The infrared (IR) spectrum of protonated azulene (AzuH+, C10H9+) has been measured in the fingerprint range (600-1800 cm-1) by means of IR multiple photon dissociation (IRMPD) spectroscopy in a Fourier transform ion cyclotron resonance mass spectrometer equipped with an electrospray ionization source using a free electron laser. The potential energy surface of AzuH+ has been characterized at the B3LYP/6-311G∗∗ level in order to determine the global and local minima and the corresponding transition states for interconversion. The energies of the local and global minima, the dissociation energies for the lowest-energy fragmentation pathways, and the proton affinity have been evaluated at the CBS-QB3 level. Comparison with calculated linear IR absorption spectra supports the assignment of the IRMPD spectrum to C4-protonated AzuH+, the most stable of the six distinguishable C-protonated AzuH+ isomers. Comparison between Azu and C4-AzuH+ reveals the effects of protonation on the geometry, vibrational properties, and the charge distribution of these fundamental aromatic molecules. Calculations at the MP2 level indicate that this technique is not suitable to predict reliable IR spectra for this type of carbocations even for relatively large basis sets. The IRMPD spectrum of protonated azulene is compared to that of isomeric protonated naphthalene and to an astronomical spectrum of the unidentified IR emission bands.

  8. Polycyclic aromatic hydrocarbons in rock oysters: a baseline study.

    PubMed

    Kagi, R; Alexander, R; Cumbers, M

    1985-01-01

    Coral-rock oysters were collected in September 1982 from six locations in the area of Mermaid Sound in North-Western Australia. Analysis was carried out by digestion of the samples, followed by solvent extraction and analysis of the extracts using HPLC-UVF and GC-MS. The levels of two- and three-ring aromatics ranged from very low for the site outside Mermaid Sound and for one site within the Sound, to low for the four other sites within the Sound. The PAH values at the latter four sites are attributed to occasional petroleum release episodes related to small boat activities and large-scale salt and iron ore shipping and general cargo activities of the Port of Dampier. The levels of PAHs with four or more rings were found to be low or very low at all sites; in fact, in most cases values measured for specific PAHs were below the limits of detection of even the very sensitive methods used in this study. Samples from sites within Mermaid Sound closest to the town and port of Dampier showed noticeably higher levels than those from outside; the present study does not allow the source of the PAHs to be determined. It is interesting to note, however, that the parent PAHs appear to form a greater proportion of the total PAH assemblage in these cases, indicating contributions from material which has been subjected to high temperature processing prior to release into the Sound.

  9. Effect of interlayer cations of montmorillonite on the biodegradation and adsorption of crude oil polycyclic aromatic compounds.

    PubMed

    Ugochukwu, Uzochukwu C; Manning, David A C; Fialips, Claire I

    2014-09-01

    Cation exchange capacity, surface acidity and specific surface area are surface properties of clay minerals that make them act as catalysts or supports in most biogeochemical processes hence making them play important roles in environmental control. However, the role of homoionic clay minerals during the biodegradation of polycyclic aromatic compounds is not well reported. In this study, the effect of interlayer cations of montmorillonites in the removal of some crude oil polycyclic aromatic compounds during biodegradation was investigated in aqueous clay/oil microcosm experiments with a hydrocarbon degrading microorganism community. The homoionic montmorillonites were prepared via cation exchange reactions by treating the unmodified montmorillonite with the relevant metallic chloride. The study indicated that potassium-montmorillonite and zinc-montmorillonite did not enhance the biodegradation of the polycyclic aromatic hydrocarbons whereas calcium-montmorillonite, and ferric-montmorillonite enhanced their biodegradation significantly. Adsorption of polycyclic aromatic hydrocarbons was significant during biodegradation with potassium- and zinc-montmorillonite where there was about 45% removal of the polycyclic aromatic compounds by adsorption in the experimental microcosm containing 5:1 ratio (w/w) of clay to oil.

  10. Biotransformation of nitro-polycyclic aromatic compounds by vegetable and fruit cell extracts*

    PubMed Central

    Xie, Bo; Yang, Jun; Yang, Qing

    2012-01-01

    Extracts from various vegetables and fruits were investigated for their abilities to reduce nitro-polycyclic aromatic hydrocarbons (NPAHs). The extracts from grape and onion exhibited an interesting selectivity, yielding corresponding hydroxylamines or amines as major products under mild conditions of 30 °C and pH 7.0. Grape extracts reduced the 4-nitro-1,8-naphthalic anhydride with the highest conversion rate (>99%) and the highest ratio of hydroxylamine to amine (95:5). In contrast, the onion extracts reduced 4-nitro-1,8-naphthalic anhydride with a conversion rate of 94% and a ratio of hydroxylamine to amine of 8:92. The thiol-reducing agent, β-mercaptoethanol, and metal cations, Ca2+ and Mg2+, greatly increased the reductive efficiency. This work provides an alternative strategy for biotransformation of nitro-polycyclic compounds. PMID:22467365

  11. Enzymatic and genetic profiles in environmental strains grown on polycyclic aromatic hydrocarbons.

    PubMed

    Cavalca, Lucia; Guerrieri, Nicoletta; Colombo, Milena; Pagani, Silvia; Andreoni, Vincenza

    2007-05-01

    The possible generation of oxidative stress induced by aromatic hydrocarbon degradation suggests that ancillary enzyme activities could facilitate the utilization of polycyclic aromatic hydrocarbons as sole carbon source. To investigate the metabolic profiles of low molecular weight polycyclic aromatic hydrocarbon-degrading strains of Sphingobium chlorophenolicum, Rhodococcus aetherovorans, Rhodococcus opacus and Mycobacterium smegmatis, the determination of the activity of putative detoxifying enzymes (rhodanese-like and glutathione S-transferase proteins) was combined with genetic analyses. All the studied strains were able to utilize phenanthrene or naphthalene. Glutathione S-transferase activity was found in S. chlorophenolicum strains grown on phenanthrene and it was related to the presence of the bphK gene, since modulation of glutathione S-transferase activity by phenanthrene paralleled the induction of glutathione S-transferase transcript in the S. chlorophenolicum strains. No glutathione S-transferase activity was detectable in R. aetherovorans, R. opacus and in M. smegmatis strains. All strains showed 3-mercaptopyruvate:cyanide sulfurtransferase activity. A rhodanese-like SseA protein was immunodetected in R. aetherovorans, R. opacus and in M. smegmatis strains, where increase of 3-mercaptopyruvate:cyanide sulfurtransferase activity was significantly induced by growth on phenanthrene.

  12. Localized enrichment of polycyclic aromatic hydrocarbons in soil, spruce needles, and lake sediments linked to in-situ bitumen extraction near Cold Lake, Alberta.

    PubMed

    Korosi, J B; Irvine, G; Skierszkan, E K; Doyle, J R; Kimpe, L E; Janvier, J; Blais, J M

    2013-11-01

    The extraction of bitumen from the Alberta oil sands using in-situ technologies is expanding at a rapid rate; however, investigations into the environmental impacts of oil sands development have focused on surface mining in the Athabasca region. We measured polycyclic aromatic hydrocarbons (PAH) in soils, spruce needles, and lake sediment cores in the Cold Lake oil sands region to provide a historical and spatial perspective on PAH contamination related to in-situ extraction activities. A pronounced increase in PAH concentrations was recorded in one of two study lakes (Hilda Lake) corresponding to the onset of commercial bitumen production in ~1985. Distance from extraction rigs was not an important predictor of PAH concentrations in soils, although two samples located near installations were elevated in alkyl PAHs. Evidence of localized PAH contamination in Hilda Lake and two soil samples suggests that continued environmental monitoring is justified to assess PAH contamination as development intensifies.

  13. Pyrolysis-gas chromatography-mass spectrometry with electron-ionization or resonance-enhanced-multi-photon-ionization for characterization of polycyclic aromatic hydrocarbons in the Baltic Sea.

    PubMed

    Otto, Stefan; Streibel, Thorsten; Erdmann, Sabrina; Klingbeil, Sophie; Schulz-Bull, Detlef; Zimmermann, Ralf

    2015-10-15

    Polycyclic aromatic hydrocarbons (PAH), as a part of dissolved organic matter (DOM), are environmental pollutants of the marine compartment. This study investigates the origin of PAH, which is supposed to derive mainly from anthropogenic activities, and their alteration along the salinity gradient of the Baltic Sea. Pyrolysis in combination with gas chromatography and two mass selective detectors in one measurement cycle are utilized as a tool for an efficient trace analysis of such complex samples, by which it is possible to detect degradation products of high molecular structures. Along the north-south transect of the Baltic Sea a slightly rising trend for PAH is visible. Their concentration profiles correspond to the ship traffic as a known anthropogenic source, underlined by the value of special isomer ratios such as phenanthrene and anthracene (0.31-0.45) or pyrene and fluoranthene (0.44-0.53). The detection of naphthalene and the distribution of its alkylated representatives support this statement.

  14. Biodegradation of Various Aromatic Compounds by Enriched Bacterial Cultures: Part A-Monocyclic and Polycyclic Aromatic Hydrocarbons.

    PubMed

    Oberoi, Akashdeep Singh; Philip, Ligy; Bhallamudi, S Murty

    2015-08-01

    Present study focused on the screening of bacterial consortium for biodegradation of monocyclic aromatic hydrocarbon (MAH) and polycyclic aromatic hydrocarbons (PAHs). Target compounds in the present study were naphthalene, acenaphthene, phenanthrene (PAHs), and benzene (MAH). Microbial consortia enriched with the above target compounds were used in screening experiments. Naphthalene-enriched consortium was found to be the most efficient consortium, based on its substrate degradation rate and its ability to degrade other aromatic pollutants with significantly high efficiency. Substrate degradation rate with naphthalene-enriched culture followed the order benzene > naphthalene > acenaphthene > phenanthrene. Chryseobacterium and Rhodobacter were discerned as the predominant species in naphthalene-enriched culture. They are closely associated to the type strain Chryseobacterium arthrosphaerae and Rhodobacter maris, respectively. Single substrate biodegradation studies with naphthalene (PAH) and benzene (MAH) were carried out using naphthalene-enriched microbial consortium (NAPH). Phenol and 2-hydroxybenzaldehyde were identified as the predominant intermediates during benzene and naphthalene degradation, respectively. Biodegradation of toluene, ethyl benzene, xylene, phenol, and indole by NAPH was also investigated. Monod inhibition model was able to simulate biodegradation kinetics for benzene, whereas multiple substrate biodegradation model was able to simulate biodegradation kinetics for naphthalene.

  15. Determination of total and polycyclic aromatic hydrocarbons in aviation jet fuel.

    PubMed

    Bernabei, M; Reda, R; Galiero, R; Bocchinfuso, G

    2003-01-24

    The aviation jet fuel widely used in turbine engine aircraft is manufactured from straight-run kerosene. The combustion quality of jet fuel is largely related to the hydrocarbon composition of the fuel itself; paraffins have better burning properties than aromatic compounds, especially naphthalenes and light polycyclic aromatic hydrocarbons (PAHs), which are characterised as soot and smoke producers. For this reason the burning quality of fuel is generally measured as smoke fermation. This evaluation is carried out with UV spectrophotometric determination of total naphthalene hydrocarbons and a chromatographic analysis to determine the total aromatic compounds. These methods can be considered insufficient to evaluate the human health impact of these compounds due to their inability to measure trace (ppm) amounts of each aromatic hyrcarbon and each PAH in accordance with limitations imposed because of their toxicological properties. In this paper two analytical methods are presented. Both are based on a gas chromatographic technique with a mass detector operating in be selected ion monitoring mode. The first method was able to determine more than 60 aromatic hydrocarbons in a fuel sample in a 35-min chromatographic run, while the second was able to carry out the analysis of more than 30 PAHs in a 40-min chromatographic run. The linearity and sensitivity of the methods in measuring these analytes at trace levels are described.

  16. Biodegradation aspects of polycyclic aromatic hydrocarbons (PAHs): a review.

    PubMed

    Haritash, A K; Kaushik, C P

    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(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

  17. Magnetic ionic liquids as non-conventional extraction solvents for the determination of polycyclic aromatic hydrocarbons.

    PubMed

    Trujillo-Rodríguez, María J; Nacham, Omprakash; Clark, Kevin D; Pino, Verónica; Anderson, Jared L; Ayala, Juan H; Afonso, Ana M

    2016-08-31

    This work describes the applicability of magnetic ionic liquids (MILs) in the analytical determination of a group of heavy polycyclic aromatic hydrocarbons. Three different MILs, namely, benzyltrioctylammonium bromotrichloroferrate (III) (MIL A), methoxybenzyltrioctylammonium bromotrichloroferrate (III) (MIL B), and 1,12-di(3-benzylbenzimidazolium) dodecane bis[(trifluoromethyl)sulfonyl)]imide bromotrichloroferrate (III) (MIL C), were designed to exhibit hydrophobic properties, and their performance examined in a microextraction method for hydrophobic analytes. The magnet-assisted approach with these MILs was performed in combination with high performance liquid chromatography and fluorescence detection. The study of the extraction performance showed that MIL A was the most suitable solvent for the extraction of polycyclic aromatic hydrocarbons and under optimum conditions the fast extraction step required ∼20 μL of MIL A for 10 mL of aqueous sample, 24 mmol L(-1) NaOH, high ionic strength content of NaCl (25% (w/v)), 500 μL of acetone as dispersive solvent, and 5 min of vortex. The desorption step required the aid of an external magnetic field with a strong NdFeB magnet (the separation requires few seconds), two back-extraction steps for polycyclic aromatic hydrocarbons retained in the MIL droplet with n-hexane, evaporation and reconstitution with acetonitrile. The overall method presented limits of detection down to 5 ng L(-1), relative recoveries ranging from 91.5 to 119%, and inter-day reproducibility values (expressed as relative standard derivation) lower than 16.4% for a spiked level of 0.4 μg L(-1) (n = 9). The method was also applied for the analysis of real samples, including tap water, wastewater, and tea infusion.

  18. Speciation of atmospheric polycyclic aromatic hydrocarbons (PAHs) present during fog time collected submicron particles.

    PubMed

    Singh, Dharmendra Kumar; Sharma, Swati; Habib, Gazala; Gupta, Tarun

    2015-08-01

    Airborne submicron particles (PM1) were collected using PM1 sampler during the fog-dominated days (December 2013-January 2014). PM1 values varied between 58.12 μg/m(3) and 198.75 μg/m(3), and average mass concentration was 162.33 ± 38.25 μg/m(3) while total average concentration of particle-associated polycyclic aromatic hydrocarbon (PAHs) determined was 616.31 ± 30.31 ng/m(3). This is a signal for an alarming high pollution level at this site situated in the Indo-Gangetic Plain (IGP). PAHs were extracted from filters using toluene and acetonitrile. Quantitative measurements of polycyclic aromatic hydrocarbons (PAHs) were carried out using the high performance liquid chromatography (HPLC) technique. The extracts were analyzed for 16 target polycyclic aromatic hydrocarbons (PAHs) including carcinogenic compound benzo(a)pyrene (19.86 ± 38.98 ng/m(3)). Fluoranthene, benzo(a)anthracene, anthracene, and fluorene were the predominant compounds found in the samples collected during foggy days. Based on number of rings, four-ring PAH compounds had maximum contribution (43%) in this fog time collected submicron particles followed by three-ring (21%), five-ring (20%), six-ring (13%), and two-ring (3%), respectively. In winter and foggy days, wood and coal combustion and biomass burning also significantly contribute to the PAH levels. However, diagnostic ratio suggests diesel emissions as the prime source of PAHs at this sampling site.

  19. Alkane, terpene and polycyclic aromatic hydrocarbon geochemistry of the Mackenzie River and Mackenzie shelf: Riverine contributions to Beaufort Sea coastal sediment

    NASA Astrophysics Data System (ADS)

    Yunker, Mark B.; Macdonald, Robie W.; Cretney, Walter J.; Fowler, Brian R.; McLaughlin, Fiona A.

    1993-07-01

    To study the largest source of river sediment to the Arctic Ocean, we have collected suspended particulates from the Mackenzie River in all seasons and sediments from the Mackenzie shelf between the river mouth and the shelf edge. These samples have been analyzed for alkanes, triterpenes and polycyclic aromatic hydrocarbons (PAHs). We found that naturally occurring hydrocarbons predominate in the river and on the shelf. These hydrocarbons include biogenic alkanes and triterpenes with a higher plant/peat origin, diagenetic PAHs from peat and plant detritus, petrogenic alkanes, triterpenes and PAHs from oil seeps and/or bitumens and combustion PAHs that are likely relict in peat deposits. Because these components vary independently, the season is found to strongly influence the concentration and composition of hydrocarbons in the Mackenzie River. While essentially the same pattern of alkanes, diagenetic hopanes and alkyl PAHs is observed in all river and most shelf sediment samples, alkane and triterpene concentration variations are strongly linked to the relative amount of higher plant/peat material. Polycyclic aromatic hydrocarbon molecular-mass profiles also appear to be tied primarily to varying proportions of peat, with an additional petrogenic component which is most likely associated with lithic material mobilized by the Mackenzie River at freshet. Consistent with the general lack of alkyl PAHs in peat, the higher PAHs found in the river are probably derived from forest and tundra fires. A few anthropogenic/pyrogenic compounds are manifest only at the shelf edge, probably due to a weakening of the river influence. We take this observation of pyrogenic PAHs and the pronounced source differences between two sediment samples collected at the shelf edge as evidence of a transition from dominance by the Mackenzie River to the geochemistry prevalent in Arctic regions far removed from major rivers.

  20. Spectral studies of polycyclic aromatic hydrocarbon interaction with human blood plasma

    NASA Astrophysics Data System (ADS)

    Melnikov, A. G.; Pravdin, A. B.; Kochubey, V. I.; Melnikov, G. V.

    2006-08-01

    Analysis of fluorescence spectra of polycyclic aromatic hydrocarbons in human blood plasma and human serum albumin solution allowed one to conclude that pyrene and also anthracene are predominantly distributed in the hydrophobic micro-phase of blood plasma proteins. In the solution of human blood plasma containing pyrene the nonmonotonic dependence of both the intensity of pyrene fluorescence and the index of polarity on the concentration of sodium dodecylsulfate added was observed. This should be connected with the reconstruction of the structure of protein globule under the surfactant action and cannot be explained only by the solubilization of pyrene in sodium dodecylsulfate micelles.