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Sample records for aromatic hydrocarbon emissions

  1. Polycyclic aromatic hydrocarbon emissions from motorcycles

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  3. An Emission Inventory of Polycyclic Aromatic Hydrocarbons in China

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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...

  5. Emissions of polycyclic aromatic hydrocarbons from coking industries in China

    Institute of Scientific and Technical Information of China (English)

    Ling Mu; Lin Peng; Junji Cao; Qiusheng He; Fan Li; Jianqiang Zhang; Xiaofeng Liu

    2013-01-01

    This study set out to assess the characteristics of polycyclic aromatic hydrocarbon (PAH) emission from coking industries,with field samplings conducted at four typical coke plants.For each selected plant,stack flue gas samples were collected during processes that included charging coal into the ovens (CC),pushing coke (PC) and the combustion of coke-oven gas (CG).Sixteen individual PAHs on the US EPA priority list were analyzed by gas chromatography/mass spectrometry (GC/MS).Results showed that the total PAH concentrations in the flue gas ranged from 45.776 to 414.874 μg/m3,with the highest emission level for CC (359.545 μg/m3).The concentration of PAH emitted from the CC process in CP1 (stamp charging) was lower than that from CP3 and CP4 (top charging).Low-molecular-weight PAHs (i.e.,two-to three-ring PAHs) were predominant contributors to the total PAH contents,and Nap,AcPy,Flu,PhA,and AnT were found to be the most abundant ones.Total BaPeq concentrations for CC (2.248 iμg/m3) were higher than those for PC (1.838 μg/m3) and CG (1.082 μg/m3),and DbA was an important contributor to carcinogenic risk as BaP in emissions from coking processes.Particulate PAH accounted for more than 20% of the total BaPeq concentrations,which were significantly higher than the corresponding contributions to the total PAH mass concentration (5%).Both particulate and gaseous PAH should be taken into consideration when the potential toxicity risk of PAH pollution during coking processes is assessed.The mean total-PAH emission factors were 346.132 and 93.173 μg/kg for CC and PC,respectively.

  6. Estimated IR and phosphorescence emission fluxes for specific Polycyclic Aromatic Hydrocarbons in the Red Rectangle

    CERN Document Server

    Mulas, G; Joblin, C; Toublanc, D

    2005-01-01

    Following the tentative identification of the blue luminescence in the Red Rectangle by Vijh et al. (2005), we compute absolute fluxes for the vibrational IR emission and phosphorescence bands of three small polycyclic aromatic hydrocarbons. The calculated IR spectra are compared with available ISO observations. A subset of the emission bands are predicted to be observable using presently available facilities, and can be used for an immediate, independent, discriminating test on their alleged presence in this well-known astronomical object.

  7. Seasonal variation of polycyclic aromatic hydrocarbons (PAHs) emissions in China.

    Science.gov (United States)

    Zhang, Yanxu; Tao, Shu

    2008-12-01

    A regression model based on the provincial energy consumption data was developed to calculate the monthly proportions of residential energy consumption compared to the total year volume. This model was also validated by comparing with some survey and statistical data. With this model, a PAHs emission inventory with seasonal variation was developed. The seasonal variations of different sources in different regions of China and the spatial distribution of the major sources in different seasons were also achieved. The PAHs emissions were larger in the winter than in the summer, with a difference of about 1.3-folds between the months with the largest and the smallest emissions. Residential solid fuel combustion dominated the pattern of seasonal variation with the winter-time emissions as much as 1.6 times as that in the summer, while the emissions from wild fires and open fire straw burning was mainly concentrated during the spring and summer. PMID:18649978

  8. Seasonal variation of polycyclic aromatic hydrocarbons (PAHs) emissions in China

    International Nuclear Information System (INIS)

    A regression model based on the provincial energy consumption data was developed to calculate the monthly proportions of residential energy consumption compared to the total year volume. This model was also validated by comparing with some survey and statistical data. With this model, a PAHs emission inventory with seasonal variation was developed. The seasonal variations of different sources in different regions of China and the spatial distribution of the major sources in different seasons were also achieved. The PAHs emissions were larger in the winter than in the summer, with a difference of about 1.3-folds between the months with the largest and the smallest emissions. Residential solid fuel combustion dominated the pattern of seasonal variation with the winter-time emissions as much as 1.6 times as that in the summer, while the emissions from wild fires and open fire straw burning was mainly concentrated during the spring and summer. - The seasonal variation of the PAHs emission in China was examined with a regression model

  9. Emission factors of carbonaceous particulate matter and polycyclic aromatic hydrocarbons from residential solid fuel combustions

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Guofeng [Jiangsu Academy of Environmental Science, Nanjing (China). Inst. of Atmospheric Sciences

    2014-07-01

    Emission inventory is basic for the understanding of environmental behaviors and potential effects of compounds, however, current inventories are often associated with relatively high uncertainties. One important reason is the lack of emission factors, especially for the residential solid fuel combustion in developing countries. In the present study, emission factors of a group of pollutants including particulate matter, organic carbon, elemental carbon (sometimes known as black carbon) and polycyclic aromatic hydrocarbons were measured for a variety of residential solid fuels including coal, crop straw, wood, and biomass pellets in rural China. The study provided a large number of emission factors that can be further used in emission estimation. Composition profiles and isomer ratios were investigated and compared so as to be used in source apportionment. In addition, the present study identified and quantified the influence of factors like fuel moisture, volatile matter on emission performance.

  10. Characteristics of polycyclic aromatic hydrocarbon emissions of particles of various sizes from smoldering incense.

    Science.gov (United States)

    Yang, T T; Lin, T S; Wu, J J; Jhuang, F J

    2012-02-01

    Release of polycyclic aromatic hydrocarbons (PAHs) in particles of various sizes from smoldering incenses was determined. Among the three types of incense investigated, yielding the total PAH emission rate and factor ranges for PM0.25 were 2,139.7-6,595.6 ng/h and 1,762.2-8,094.9 ng/g, respectively. The PM0.25/PM2.5 ratio of total PAH emission factors and rates from smoldering three incenses was greater than 0.92. This study shows that total particle PAH emission rates and factors were mainly incenses. The benzo[a]pyrene accounted for 65.2%-68.0% of the total toxic equivalency emission factor of PM2.5 for the three incenses. Experimental results clearly indicate that the PAH emission rates and factors were influenced significantly by incense composition, including carbon and hydrogen content. The study concludes that smoldering incense with low atomic hydrogen/carbon ratios minimized the production of total polycyclic aromatic hydrocarbons of both PM2.5 and PM0.25.

  11. Random mixtures of polycyclic aromatic hydrocarbon spectra match interstellar infrared emission

    CERN Document Server

    Rosenberg, Marissa J F; Boersma, Christiaan

    2014-01-01

    The mid-infrared (IR; 5-15~$\\mu$m) spectrum of a wide variety of astronomical objects exhibits a set of broad emission features at 6.2, 7.7, 8.6, 11.3 and 12.7 $\\mu$m. About 30 years ago it was proposed that these signatures are due to emission from a family of UV heated nanometer-sized carbonaceous molecules known as polycyclic aromatic hydrocarbons (PAHs), causing them to be referred to as aromatic IR bands (AIBs). Today, the acceptance of the PAH model is far from settled, as the identification of a single PAH in space has not yet been successful and physically relevant theoretical models involving ``true'' PAH cross sections do not reproduce the AIBs in detail. In this paper, we use the NASA Ames PAH IR Spectroscopic Database, which contains over 500 quantum-computed spectra, in conjunction with a simple emission model, to show that the spectrum produced by any random mixture of at least 30 PAHs converges to the same 'kernel'-spectrum. This kernel-spectrum captures the essence of the PAH emission spectrum...

  12. Global atmospheric emission inventory of polycyclic aromatic hydrocarbons (PAHs) for 2004

    Science.gov (United States)

    Zhang, Yanxu; Tao, Shu

    The global atmospheric emissions of the 16 polycyclic aromatic hydrocarbons (PAHs) listed as the US EPA priority pollutants were estimated using reported emission activity and emission factor data for the reference year 2004. A database for emission factors was compiled, and their geometric means and frequency distributions applied for emission calculation and uncertainty analysis, respectively. The results for 37 countries were compared with other PAH emission inventories. It was estimated that the total global atmospheric emission of these 16 PAHs in 2004 was 520 giga grams per year (Gg y -1) with biofuel (56.7%), wildfire (17.0%) and consumer product usage (6.9%) as the major sources, and China (114 Gg y -1), India (90 Gg y -1) and United States (32 Gg y -1) were the top three countries with the highest PAH emissions. The PAH sources in the individual countries varied remarkably. For example, biofuel burning was the dominant PAH source in India, wildfire emissions were the dominant PAH source in Brazil, while consumer products were the major PAH emission source in the United States. In China, in addition to biomass combustion, coke ovens were a significant source of PAHs. Globally, benzo(a)pyrene accounted for 0.05% to 2.08% of the total PAH emission, with developing countries accounting for the higher percentages. The PAH emission density varied dramatically from 0.0013 kg km -2 y in the Falkland Islands to 360 kg km -2 y in Singapore with a global mean value of 3.98 kg km -2 y. The atmospheric emission of PAHs was positively correlated to the country's gross domestic product and negatively correlated with average income. Finally, a linear bivariate regression model was developed to explain the global PAH emission data.

  13. Evaluating emission levels of polycyclic aromatic hydrocarbons from organic materials by analytical pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Fabbri, Daniele; Vassura, Ivano [Laboratory of Chemistry, C.I.R.S.A., University of Bologna, via S. Alberto 163, I-48100 Ravenna (Italy)

    2006-03-01

    A procedure in off-line analytical pyrolysis was investigated for the rapid determination of polycyclic aromatic hydrocarbons (PAHs) evolved from thermal degradation of organic materials. Samples spiked with perdeuterated PAHs were pyrolysed at 1000{sup o}C for 60s by means of a resistively heated filament pyrolyser inserted into a glass chamber connected to a cartridge with a sorbent (XAD-2 resin). PAHs trapped onto the resin were extracted with dichloromethane and analysed by gas chromatography-mass spectrometry (GC-MS). The analytical performance of the overall procedure (precision, recovery, effect of experimental parameters) was evaluated by pyrolysing a bituminous coal certified reference material (CRM). Emission levels of naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, acenaphtylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene were determined for bituminous and anthracite coals, tyre, and cellulose. Despite some limitations, the method was adequate to the purpose of quantitatively measuring the tendency of various materials to release volatile PAHs upon heating. (author)

  14. Superconductivity in aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Kubozono, Yoshihiro, E-mail: kubozono@cc.okayama-u.ac.jp [Research Laboratory for Surface Science, Okayama University, Okayama 700-8530 (Japan); Research Center of New Functional Materials for Energy Production, Storage and Transport, Okayama University, Okayama 700-8530 (Japan); Japan Science and Technology Agency, ACT-C, Kawaguchi 332-0012 (Japan); Goto, Hidenori; Jabuchi, Taihei [Research Laboratory for Surface Science, Okayama University, Okayama 700-8530 (Japan); Yokoya, Takayoshi [Research Laboratory for Surface Science, Okayama University, Okayama 700-8530 (Japan); Research Center of New Functional Materials for Energy Production, Storage and Transport, Okayama University, Okayama 700-8530 (Japan); Kambe, Takashi [Department of Physics, Okayama University, Okayama 700-8530 (Japan); Sakai, Yusuke; Izumi, Masanari; Zheng, Lu; Hamao, Shino; Nguyen, Huyen L.T. [Research Laboratory for Surface Science, Okayama University, Okayama 700-8530 (Japan); Sakata, Masafumi; Kagayama, Tomoko; Shimizu, Katsuya [Center of Science and Technology under Extreme Conditions, Osaka University, Osaka 560-8531 (Japan)

    2015-07-15

    Highlights: • Aromatic superconductor is one of core research subjects in superconductivity. Superconductivity is observed in certain metal-doped aromatic hydrocarbons. Some serious problems to be solved exist for future advancement of the research. This article shows the present status of aromatic superconductors. - Abstract: ‘Aromatic hydrocarbon’ implies an organic molecule that satisfies the (4n + 2) π-electron rule and consists of benzene rings. Doping solid aromatic hydrocarbons with metals provides the superconductivity. The first discovery of such superconductivity was made for K-doped picene (K{sub x}picene, five benzene rings). Its superconducting transition temperatures (T{sub c}’s) were 7 and 18 K. Recently, we found a new superconducting K{sub x}picene phase with a T{sub c} as high as 14 K, so we now know that K{sub x}picene possesses multiple superconducting phases. Besides K{sub x}picene, we discovered new superconductors such as Rb{sub x}picene and Ca{sub x}picene. A most serious problem is that the shielding fraction is ⩽15% for K{sub x}picene and Rb{sub x}picene, and it is often ∼1% for other superconductors. Such low shielding fractions have made it difficult to determine the crystal structures of superconducting phases. Nevertheless, many research groups have expended a great deal of effort to make high quality hydrocarbon superconductors in the five years since the discovery of hydrocarbon superconductivity. At the present stage, superconductivity is observed in certain metal-doped aromatic hydrocarbons (picene, phenanthrene and dibenzopentacene), but the shielding fraction remains stubbornly low. The highest priority research area is to prepare aromatic superconductors with a high superconducting volume-fraction. Despite these difficulties, aromatic superconductivity is still a core research target and presents interesting and potentially breakthrough challenges, such as the positive pressure dependence of T{sub c} that is clearly

  15. Global atmospheric emissions and transport of polycyclic aromatic hydrocarbons: Evaluation of modeling and transboundary pollution

    Science.gov (United States)

    Shen, Huizhong; Tao, Shu

    2014-05-01

    Global atmospheric emissions of 16 polycyclic aromatic hydrocarbons (PAHs) from 69 major sources were estimated for a period from 1960 to 2030. Regression models and a technology split method were used to estimated country and time specific emission factors, resulting in a new estimate of PAH emission factor variation among different countries and over time. PAH emissions in 2007 were spatially resolved to 0.1° × 0.1° grids based on a newly developed global high-resolution fuel combustion inventory (PKU-FUEL-2007). MOZART-4 (The Model for Ozone and Related Chemical Tracers, version 4) was applied to simulate the global tropospheric transport of Benzo(a)pyrene, one of the high molecular weight carcinogenic PAHs, at a horizontal resolution of 1.875° (longitude) × 1.8947° (latitude). The reaction with OH radical, gas/particle partitioning, wet deposition, dry deposition, and dynamic soil/ocean-air exchange of PAHs were considered. The simulation was validated by observations at both background and non-background sites, including Alert site in Canadian High Arctic, EMEP sites in Europe, and other 254 urban/rural sites reported from literatures. Key factors effecting long-range transport of BaP were addressed, and transboundary pollution was discussed.

  16. Emission factors of polycyclic aromatic hydrocarbons from domestic coal combustion in China.

    Science.gov (United States)

    Geng, Chunmei; Chen, Jianhua; Yang, Xiaoyang; Ren, Lihong; Yin, Baohui; Liu, Xiaoyu; Bai, Zhipeng

    2014-01-01

    Domestic coal stove is widely used in China, especially for countryside during heating period of winter, and polycyclic aromatic hydrocarbons (PAHs) are important in flue gas of the stove. By using dilution tunnel system, samples of both gaseous and particulate phases from domestic coal combustion were collected and 18 PAH species were analyzed by GC-MS. The average emission factors of total 18 PAH species was 171.73 mg/kg, ranging from 140.75 to 229.11 mg/kg for bituminous coals, while was 93.98 mg/kg, ranging from 58.48 to 129.47 mg/kg for anthracite coals. PAHs in gaseous phases occupied 95% of the total of PAHs emission of coal combustion. In particulate phase, 3-ring and 4-ring PAHs were the main components, accounting for 80% of the total particulate PAHs. The total toxicity potency evaluated by benzo[a]pyrene-equivalent carcinogenic power, sum of 7 carcinogenic PAH components and 2,3,7,8-tetrachlorodibenzodioxin had a similar tendency. And as a result, the toxic potential of bituminous coal was higher than that of anthracite coal. Efficient emission control should be conducted to reduce PAH emissions in order to protect ecosystem and human health.

  17. Polycyclic aromatic hydrocarbon and mid-infrared continuum emission in a z > 4 submillimeter galaxy

    Energy Technology Data Exchange (ETDEWEB)

    Riechers, Dominik A. [Department of Astronomy, Cornell University, 220 Space Sciences Building, Ithaca, NY 14853 (United States); Pope, Alexandra [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Daddi, Emanuele; Elbaz, David [Laboratoire AIM, CEA/DSM-CNRS-Université Paris Diderot, Irfu/Service d' Astrophysique, CEA Saclay, Orme des Merisiers, F-91191 Gif-sur-Yvette Cedex (France); Armus, Lee; Chary, Ranga-Ram [Spitzer Science Center, California Institute of Technology, MC 220-6, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Carilli, Christopher L. [National Radio Astronomy Observatory, PO Box O, Socorro, NM 87801 (United States); Walter, Fabian; Hodge, Jacqueline [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Morrison, Glenn E. [Canada-France-Hawaii Telescope, 65-1238 Mamalahoa Hwy, Kamuela, HI 96743-8432 (United States); Dickinson, Mark [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Dannerbauer, Helmut, E-mail: dr@astro.cornell.edu [Institut für Astrophysik, Universität Wien, Türkenschanzstraße 17, A-1180 Wien (Austria)

    2014-05-01

    We report the detection of 6.2 μm polycyclic aromatic hydrocarbon (PAH) and rest-frame 4-7 μm continuum emission in the z = 4.055 submillimeter galaxy GN20, using the Infrared Spectrograph on board the Spitzer Space Telescope. This represents the first detection of PAH emission at z > 4. The strength of the PAH emission feature is consistent with a very high star formation rate of ∼1600 M {sub ☉} yr{sup –1}. We find that this intense starburst powers at least ∼1/3 of the faint underlying 6 μm continuum emission, with an additional, significant (and perhaps dominant) contribution due to a power-law-like hot dust source, which we interpret to likely be a faint, dust-obscured active galactic nucleus (AGN). The inferred 6 μm AGN continuum luminosity is consistent with a sensitive upper limit on the hard X-ray emission as measured by the Chandra X-Ray Observatory if the previously undetected AGN is Compton-thick. This is in agreement with the finding at optical/infrared wavelengths that the galaxy and its nucleus are heavily dust-obscured. Despite the strong power-law component enhancing the mid-infrared continuum emission, the intense starburst associated with the photon-dominated regions that give rise to the PAH emission appears to dominate the total energy output in the infrared. GN20 is one of the most luminous starburst galaxies known at any redshift, embedded in a rich protocluster of star-forming galaxies. This investigation provides an improved understanding of the energy sources that power such exceptional systems, which represent the extreme end of massive galaxy formation at early cosmic times.

  18. The Luminous Polycyclic Aromatic Hydrocarbon Emission Features: Applications to High Redshift Galaxies and Active Galactic Nuclei

    Science.gov (United States)

    Shipley, Heath V.

    2016-01-01

    For decades, significant work has been applied to calibrating emission from the ultra-violet, nebular emission lines, far-infrared, X-ray and radio as tracers of the star-formation rate (SFR) in distant galaxies. Understanding the exact rate of star-formation and how it evolves with time and galaxy mass has deep implications for how galaxies form. The co-evolution of star-formation and supermassive black hole (SMBH) accretion is one of the key problems in galaxy formation theory. But, many of these SFR indicators are influenced by SMBH accretion in galaxies and result in unreliable SFRs. Utilizing the luminous polycyclic aromatic hydrocarbon (PAH) emission features, I provide a new robust SFR calibration using the luminosity emitted from the PAHs at 6.2μm, 7.7μm and 11.3μm to solve this. The PAH features emit strongly in the mid-infrared (mid-IR; 5-25μm) mitigating dust extinction, containing on average 5-10% of the total IR luminosity in galaxies. I use a sample of 105 star-forming galaxies covering a range of total IR luminosity, LIR = L(8-1000μm) = 109 - 1012 L⊙ and redshift 0 blackhole accretion contemporaneously in a galaxy.

  19. Emission of polycyclic aromatic hydrocarbons and lead during Chinese mid-autumn festival.

    Science.gov (United States)

    Kuo, Chung-Yih; Lee, Hong-Shen; Lai, Jeang-Hung

    2006-07-31

    The emission factors of total particulate polycyclic aromatic hydrocarbons (PAHs), Benzo(a)pyrene (BaP), BaP-equivalent doses (BaP(eq)) and Pb for burning three kinds of charcoal were investigated in this study: fast-lighting charcoal, Taiwanese, and Indonesian charcoal (the latter two of which are not fast-lighting). Compared to the burning of Taiwanese and Indonesian charcoal, the burning of fast-lighting charcoal can emit much larger amounts of total PAHs, BaP(eq) and Pb into the atmosphere. The emission factors of total PAHs, BaP and BaP(eq) for broiling meat were noticeably higher than those for broiling vegetables and non-fish seafood. When using Indonesian charcoal to broil meat, the total emission factors of particulate PAHs and BaP were about 15.7 and 0.39 mg/kg, respectively. The total amounts of particulate PAHs and Pb emitted from cookouts during Mid-Autumn Festival were 2881 and 120 g, respectively. Total PAHs and BaP(eq) in PM(10) aerosols on Mid-Autumn Festival nights increased about 1.6 and 1.5 times, respectively, higher than those on non-festival nights. The mean concentration of Pb on the nights of Mid-Autumn Festival increases to about 2.8 times that of non-festival nights.

  20. Polycyclic aromatic hydrocarbon emissions from the combustion of alternative fuels in a gas turbine engine.

    Science.gov (United States)

    Christie, Simon; Raper, David; Lee, David S; Williams, Paul I; Rye, Lucas; Blakey, Simon; Wilson, Chris W; Lobo, Prem; Hagen, Donald; Whitefield, Philip D

    2012-06-01

    We report on the particulate-bound polycyclic aromatic hydrocarbons (PAH) in the exhaust of a test-bed gas turbine engine when powered by Jet A-1 aviation fuel and a number of alternative fuels: Sasol fully synthetic jet fuel (FSJF), Shell gas-to-liquid (GTL) kerosene, and Jet A-1/GTL 50:50 blended kerosene. The concentration of PAH compounds in the exhaust emissions vary greatly between fuels. Combustion of FSJF produces the greatest total concentration of PAH compounds while combustion of GTL produces the least. However, when PAHs in the exhaust sample are measured in terms of the regulatory marker compound benzo[a]pyrene, then all of the alternative fuels emit a lower concentration of PAH in comparison to Jet A-1. Emissions from the combustion of Jet A-1/GTL blended kerosene were found to have a disproportionately low concentration of PAHs and appear to inherit a greater proportion of the GTL emission characteristics than would be expected from volume fraction alone. The data imply the presence of a nonlinear relation between fuel blend composition and the emission of PAH compounds. For each of the fuels, the speciation of PAH compounds present in the exhaust emissions were found to be remarkably similar (R(2) = 0.94-0.62), and the results do provide evidence to support the premise that PAH speciation is to some extent indicative of the emission source. In contrast, no correlation was found between the PAH species present in the fuel with those subsequently emitted in the exhaust. The results strongly suggests that local air quality measured in terms of the particulate-bound PAH burden could be significantly improved by the use of GTL kerosene either blended with or in place of Jet A-1 kerosene.

  1. Characterization and concentrations of polycyclic aromatic hydrocarbons in emissions from different heating systems in Damascus, Syria.

    Science.gov (United States)

    Alkurdi, Farouk; Karabet, François; Dimashki, Marwan

    2014-04-01

    Traffic has long been recognized as the major contributor to polycyclic aromatic hydrocarbon (PAH) emissions to the urban atmosphere. Stationary combustion sources, including residential space heating systems, are also a major contributor to PAH emissions. The aim of this study was to determine the profile and concentration of PAHs in stack flue gas emissions from different kinds of space heaters in order to increase the understanding of the scale of the PAH pollution problem caused by this source. This study set out to first assess the characteristics of PAHs and their corresponding benzo[a]pyrene equivalent emissions from a few types of domestic heaters and central heating systems to the urban atmosphere. The study, enabled for the first time, the characterization of PAHs in stationary combustion sources in the city of Damascus, Syria. Nine different types of heating systems were selected with respect to age, design, and type of fuel burned. The concentrations of 15 individual PAH compounds in the stack flue gas were determined in the extracts of the collected samples using high-performance liquid chromatography system (HPLC) equipped with ultraviolet-visible and fluorescence detectors. In general, older domestic wood stoves caused considerably higher PAH emissions than modern domestic heaters burning diesel oil. The average concentration of ΣPAH (sum of 15 compounds) in emissions from all types of studied heating systems ranged between 43 ± 0.4 and 316 ± 1.4 μg/m(3). Values of total benzo[a]pyrene equivalent ranged between 0.61 and 15.41 μg/m(3).

  2. Indoor emission, dispersion and exposure of total particle-bound polycyclic aromatic hydrocarbons during cooking

    Science.gov (United States)

    Gao, Jun; Jian, Yating; Cao, Changsheng; Chen, Lei; Zhang, Xu

    2015-11-01

    Cooking processes highly contribute to indoor polycyclic aromatic hydrocarbon (PAH) pollution. High molecular weight and potentially carcinogenic PAHs are generally found attached to small particles, i.e., particulate phase PAHs (PPAHs). Due to the fact that indoor particle dynamics have been clear, describing the indoor dynamics of cooking-generated PPAHs within a specific time span is possible. This paper attempted to quantify the dynamic emission rate, simultaneous spatial dispersion and individual exposure of PPAHs using a cooking source. Experiments were conducted in a real-scale kitchen chamber to elucidate the time-resolved emission and effect of edible oil temperature and mass. Numerical simulations based on indoor particle dynamics were performed to obtain the spatial dispersion and individual inhalation intake of PPAHs under different emission and ventilation conditions. The present work examined the preheating cooking stage, at which edible oil is heated up to beyond its smoke point. The dynamic emission rate peak point occurred much earlier than the oil heating temperature. The total PPAH emission ranged from 2258 to 6578 ng upon heating 40-85 g of edible oil. The overall intake fraction by an individual within a period of 10 min, including 3 min for heating and 7 min for natural cooling, was generally ∼1/10,000. An important outcome of this work was that the overall intake fraction could be represented by multiplying the range hood escape efficiency by the inhalation-to-ventilation rate ratio, which would be no greater than the same ratio. The methodology and results of this work were extendible for the number-based assessment of PPAHs. This work is expected to help us understand the health risks due to inhalation exposure to cooking-generated PPAHs in the kitchen.

  3. Biomonitoring of polycyclic aromatic hydrocarbons from coke oven emissions and reproductive toxicity in nonsmoking workers.

    Science.gov (United States)

    Jeng, Hueiwang Anna; Pan, Chih-Hong; Lin, Wen-Yi; Wu, Ming-Tsang; Taylor, Steven; Chang-Chien, Guo-Ping; Zhou, Guodong; Diawara, Norou

    2013-01-15

    The objective of the cross-sectional study was to assess whether exposure to polycyclic aromatic hydrocarbons (PAHs) from coke oven emissions contributed to alteration of semen quality and sperm DNA integrity in nonsmoking workers. Nonsmoking coke oven workers from a steel plant in Taiwan served as the exposure groups (topside-oven workers for the high exposure group and side-oven workers for the low exposure group), and administrators and security personnel in the plant served as the control. An exposure assessment was conducted to determine both particulate and gaseous phase of PAH levels and urinary 1-hydroxypyrene (1-OHP) levels. Semen quality was analyzed according to WHO guidelines. DNA fragmentation and bulky DNA adducts were measured to assess sperm DNA integrity. There was no significant difference in sperm concentrations, vitality, and DNA fragmentation between the exposed group and the control. The high exposure group experienced significantly lower percentages of normal morphology as compared with the control (p=0.0001). Bulky DNA adducts were detected in the exposed group that were significant higher than the control (p=0.04). Exposure to PAHs from coke-oven emissions could contribute to increased levels of bulky DNA adducts in sperm. PMID:23314003

  4. POLYCYCLIC AROMATIC HYDROCARBON EMISSION IN SPITZER/IRS MAPS. I. CATALOG AND SIMPLE DIAGNOSTICS

    Energy Technology Data Exchange (ETDEWEB)

    Stock, D. J.; Choi, W. D.-Y.; Moya, L. G. V.; Otaguro, J. N.; Sorkhou, S.; Peeters, E. [Department of Physics and Astronomy, University of Western Ontario, London, ON, N6A 3K7 (Canada); Allamandola, L. J. [NASA Ames Research Center, MS 245-6, Moffett Field, CA 94035-0001 (United States); Tielens, A. G. G. M., E-mail: dstock4@uwo.ca [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA (Netherlands)

    2016-03-01

    We present a sample of resolved galactic H ii regions and photodissociation regions (PDRs) observed with the Spitzer infrared spectrograph in spectral mapping mode between the wavelengths of 5–15 μm. For each object we have spectral maps at a spatial resolution of ∼4″ in which we have measured all of the mid-infrared emission and absorption features. These include the polycyclic aromatic hydrocarbon (PAH) emission bands, primarily at 6.2, 7.7, 8.6, 11.2, and 12.7 μm, as well as the spectral emission lines of neon and sulfur and the absorption band caused by silicate dust at around 9.8 μm. In this work we describe the data in detail, including the data reduction and measurement strategies, and subsequently present the PAH emission band intensity correlations for each of the objects and the sample as a whole. We find that there are distinct differences between the sources in the sample, with two main groups: the first comprising the H ii regions and the second the reflection nebulae (RNe). Three sources—the reflection nebula NGC 7023, the Horsehead nebula PDR (an interface between the H ii region IC 434 and the Orion B molecular cloud), and M17—resist this categorization, with the Horsehead PDR points mimicking the RNe and the NGC 7023 fluxes displaying a unique bifurcated appearance in our correlation plots. These discrepancies seem to be due to the very low radiation field experienced by the Horsehead PDR and the very clean separation between the PDR environment and a diffuse environment in the NGC 7023 observations.

  5. Emission characteristics of polycyclic aromatic hydrocarbons from combustion of different residential coals in North China

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Wen X. [Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871 (China)], E-mail: wxliu@urban.pku.edu.cn; Dou Han; Wei, Zhi C.; Chang Biao; Qiu, Wei X.; Liu Yuan; Tao Shu [Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871 (China)

    2009-02-01

    Emission properties of polycyclic aromatic hydrocarbons (PAHs) from combustion of six residential coals in North China were investigated. The results indicated that, the total emission factors (EFs) for 15 PAH species in gaseous and particulate phases ranged from 52.8 to 1434.8 mg/kg with a decreasing sequence of local bituminous coals and anthracite coals, and honeycomb briquettes were largely dependent on the raw coals used to produce them. Particulate phase, dominated by median or high molecular weight components, made a major contribution (68.8% - 76.5%) to the total EFs for bituminous coals, while gaseous phase with principal low molecular weight species accounted for most (86.3% - 97.9%) of the total EFs for anthracite coals. The phase partitioning of PAH emission for honeycomb briquettes was similarly dependent on the crude coals. The total EFs, phase partitioning and component profiles of emitted PAHs were mainly influenced by the inner components of the studied coals. Burning mode and flue number on household coal-stoves also affected the emission characteristics by means of the oxygen supply. A sum of seven carcinogenic PAHs, benzo(a)pyrene(BaP)-equivalent carcinogenic power and total toxicity potency expressed in 2,3,7,8-tetrachlorodibenzo-dioxin(TCDD) toxic equivalence exhibited that bituminous coals and produced honeycomb briquettes had remarkably elevated values. Fluoranthene, benzo(b)fluoranthene, benzo(k)fluoranthene, chrysene and indeno(1,2,3-cd)pyrene from anthracite coals showed higher levels of BaP-based toxic equivalent factor, though the other toxicity indices were rather low for this type of coal.

  6. Emissions of polyciclic aromatic hydrocarbons and polyciclic carbonyl biphenils from electric arc furnaces

    Directory of Open Access Journals (Sweden)

    P. Gomes, J. F.

    2008-06-01

    Full Text Available This paper describes work done in order to determine the emissions of highly toxic organic micropollutants from electric arc furnaces used in the production of carbon steel from scrap. The study will be allowing to derive relationships between the levels of airborne micropollutants and the operational parameters of the production process so that an abatement of pollution could be achieved. By using the European standard method CEN 1948 for dioxin like compounds sampling and measurement, it was possible to determine the characteristic fingerprint of micropollutants such as polyciclic aromatic hydrocarbons (PAHs and polycyclic carbonyl biphenils (PCBs emitted by this particular stationary source.

    Este artículo contiene resultados del trabajo ejecutado para estudiar la determinación de las emisiones de los micropolutantes orgánicos muy tóxicos que se emiten por los hornos eléctricos de arco utilizados en la producción de acero. Este estudio inicial va a permitir relacionar las concentraciones de polutantes emitidos a la atmósfera con las condiciones de operación del horno eléctrico de arco. Utilizando el método normalizado CEN 1948 para captación y análisis de muestras de compuestos análogos a las dioxinas ha sido posible determinar el perfil característico de los micropolutantes tales como PAHs y PCBs emitidos por esta fuente.

  7. POLYCYCLIC AROMATIC HYDROCARBON EMISSION IN THE PROPLYD HST10: WHAT IS THE MECHANISM BEHIND PHOTOEVAPORATION?

    International Nuclear Information System (INIS)

    Proplyds are photodissociation-region-(PDR)-like cometary cocoons around young stars which are thought to originate through photoevaporation of the central protoplanetary disk by external UV radiation from the nearby OB stars. This Letter presents spatially resolved mid-infrared imaging and spectroscopy of the proplyd HST10 obtained with the Very Large Telescope/VISIR instrument. These observations allow us to detect polycyclic aromatic hydrocarbon (PAH) emission in the proplyd PDR and to study the general properties of PAHs in proplyds for the first time. We find that PAHs in HST10 are mostly neutral and at least 50 times less abundant than typical values found for the diffuse interstellar medium or the nearby Orion Bar. With such a low PAH abundance, photoelectric heating is significantly reduced. If this low abundance pertains also to the original disk material, gas heating rates could be too low to efficiently drive photoevaporation unless other processes can be identified. Alternatively, the model behind the formation of proplyds as evaporating disks may have to be revised.

  8. Polycyclic aromatic hydrocarbon (PAH) emission from co-firing municipal solid waste (MSW) and coal in a fluidized bed incinerator

    Energy Technology Data Exchange (ETDEWEB)

    You, X.F. [China United Engineering Corporation, Hangzhou (China)

    2008-07-01

    Polycyclic aromatic hydrocarbons (PAH) emissions from a commercial municipal solid waste incinerator (MSWI) were studied. A MSW-coal mixture and coal only were used as fuel for the fluidized bed incinerator. Seven sampling points were chosen according to the classified four PAH emission pathways: flue gas, residue, ash and water. The mixture of MSW and coal resulted in PAH emission more than that of coal only, and PAH emission increased with increasing MSW mass percentage. Calcium oxide (CaO) or calcium carbonate (CaCO{sub 3}) was added its it desulfurizer. PAH emission also changed with different desulfurizers because of their different influences on heat balance. The PAH toxic equivalent (TEQ) of all operating conditions was also examined, showing that total daily PAH emission from MSWI can be determined.

  9. Impact of using fishing boat fuel with high poly aromatic content on the emission of polycyclic aromatic hydrocarbons from the diesel engine

    Science.gov (United States)

    Lin, Yuan-Chung; Lee, Wen-Jhy; Li, Hsing-Wang; Chen, Chung-Ban; Fang, Guor-Cheng; Tsai, Perng-Jy

    Because of the fishery subsidy policy, the fishing boat fuel oil (FBFO) exemption from commodity taxes, business taxes and air pollution control fees, resulted in the price of FBFO was ˜50% lower than premium diesel fuel (PDF) in Taiwan. It is estimated that ˜650,000 kL FBFO was illegally used by traveling diesel-vehicles (TDVs) with a heavy-duty diesel engine (HDDE), which accounted for ˜16.3% of the total diesel fuel consumed by TDVs. In this study, sulfur, poly aromatic and total-aromatic contents in both FBFO and PDF were measured and compared. Exhaust emissions of polycyclic aromatic hydrocarbons (PAHs) and their carcinogenic potencies (BaP eq) from a HDDE under transient cycle testing for both FBFO and PDF were compared and discussed. Finally, the impact caused by the illegal use of FBFO on the air quality was examined. Results show that the mean sulfur-, poly aromatic and aromatic-contents in FBFO were 43.0, 3.89 and 1.04 times higher than that of PDF, respectively. Emission factors of total-PAHs and total-BaP eq obtained by utilizing FBFO were 51.5 and 0.235 mg L -1-Fuel, which were 3.41 and 5.82 times in magnitude higher than obtained by PDF, respectively. The estimated annual emissions of total-PAHs and total-BaP eq to the ambient environment due to the illegally used FBFO were 23.6 and 0.126 metric tons, respectively, which resulted in a 17.9% and a 25.0% increment of annual emissions from all mobile sources, respectively. These results indicated that the FBFO used illegally by TDVs had a significant impact on PAH emissions to the ambient environment.

  10. Production of alkyl aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Bonacci, J.C.; Billings, R.P.

    1975-01-30

    An improved method is claimed for producing aromatic hydrocarbons from a hydrocarbon charge containing aromatic hydrocarbons including benzene and C/sub 8/ alkyl aromatics and aliphatic hydrocarbons which charge is rich in such aromatic hydrocarbons and lean in aliphatic hydrocarbons boiling above about 220/sup 0/F by reason of conversion under severe conditions which comprises subjecting said charge to distillation conditions of temperature and pressure such that at least a portion of the benzene content of said fraction is separated as vapor from an alkyl aromatic fraction containing aliphatic hydrocarbons and the major portion of C/sub 8/ aromatics in said charge, reacting said alkyl aromatic fraction in the presence of hydrogen in contact with a catalyst containing type ZSM-5 zeolite, zeolite ZSM-12, zeolite ZSM-21 or zeolite beta in combination with a hydrogenation/dehydrogenation component at conversion conditions to convert aliphatic hydrocarbons to lower boiling material of five carbon atoms and lighter separable from aromatics by distillation including a temperature of about 500/sup 0/ to 1000/sup 0/F, a pressure of about 100 to about 600 pounds, a hydrogen to hydrocarbon mol ratio of 0.2 to 8 and weight hourly space velocity of 0.5 to 15, concurrently contacting a mixture of hydrogen and toluene with a disproportionation catalyst under reaction conditions to disproportionate said toluene, combining the effluents of said contacting steps, separating hydrogen from the combined effluents of said contacting steps, separating hydrogen from the combined effluents, recycling at least a portion of said separated hydrogen to said contacting steps, distilling the hydrocarbon residue from said separation step to recover therefrom at least toluene and mixed xylenes, and recycling at least a portion of said recovered toluene as feed to the disproportionation step aforesaid.

  11. Semi-Volatile and Particulate Polycyclic Aromatic Hydrocarbons inEnvironmental Tobacco Smoke: Cleanup, Speciation and EmissionsFactors

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-02-01

    Studies of phase distributions and emission factors for polycyclic aromatic hydrocarbons (PAH) in environmental tobacco smoke (ETS) require collection and analysis of very small samples. To achieve the necessary selectivity and sensitivity, a method has been devised and tested for extraction and cleanup of gas- and particulate-phase ETS samples. Gas-phase species were trapped by polymeric sorbents, and particles were trapped on filters. The samples were extracted with hot cyclohexane, concentrated and passed through silica solid-phase extraction columns for cleanup. After solvent change, the PAH were determined by high performance liquid chromatography with two programmed fluorescence detectors. PAH concentrations in 15-mg aliquots of National Institute of Standards and Technology Standard Reference Material SRM 1649 (Urban DustIOrganics) agreed well with published values. Relative precision at the 95% confidence level was 8% for SRM 1649 and 20% for replicate samples (5 mg) of ETS particles. Emission factors have been measured for a range of gas- and particulate-phase polycyclic aromatic hydrocarbons in ETS. The emission factors per cigarette were 13.0{+-}0.5 mg particulate matter, 11.2{+-}0.9 pg for gas-phase naphthalene and 74{+-}10 {micro}g for particulate benzo(a)pyrene.

  12. The ir emission features: Emission from PAH [Polycyclic Aromatic Hydrocarbons] molecules and amorphous carbon particles

    International Nuclear Information System (INIS)

    PAHs can have several forms in the interstellar medium. To assess the importance of each requires the availability of a collection of high quality, complete mid-ir interstellar emission spectra, a collection of laboratory spectra of PAH samples prepared under realistic conditions and a firm understanding of the microscopic emission mechanism. Given what we currently know about PAHs, the spectroscopic data suggests that there are at least two components which contribute to the interstellar emission spectrum: free molecule sized PAHs producing the narrow features and amorphous carbon particles (which are primarily made up of an irregular ''lattice'' of PAHs) contributing to the broad underlying components. An exact treatment of the ir fluorescence from highly vibrationally excited large molecules shows that species containing between 20 and 30 carbon atoms are responsible for the narrow features, although the spectra match more closely with the spectra of amorphous carbon particles. Since little is known about the spectroscopic properties of free PAHs and PAH clusters, much laboratory work is called for in conjunction with an observational program which focuses on the spatial characteristics of the spectra. In this way the distribution and evolution of carbon from molecule to particle can be traced. 38 refs., 9 figs

  13. Bioassay of polycyclic aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    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.

  14. Deuterated polycyclic aromatic hydrocarbons: Revisited

    CERN Document Server

    Doney, Kirstin D; Mori, Tamami; Onaka, Takashi; Tielens, A G G M

    2016-01-01

    The amount of deuterium locked up in polycyclic aromatic hydrocarbons (PAHs) has to date been an uncertain value. We present a near-infrared (NIR) spectroscopic survey of HII regions in the Milky Way, Large Magellanic Cloud (LMC), and Small Magellanic Cloud (SMC) obtained with AKARI, which aims to search for features indicative of deuterated PAHs (PAD or Dn-PAH) to better constrain the D/H ratio of PAHs. Fifty-three HII regions were observed in the NIR (2.5-5 {\\mu}m), using the Infrared Camera (IRC) on board the AKARI satellite. Through comparison of the observed spectra with a theoretical model of deuterated PAH vibrational modes, the aromatic and (a)symmetric aliphatic C-D stretch modes were identified. We see emission features between 4.4-4.8 {\\mu}m, which could be unambiguously attributed to deuterated PAHs in only six of the observed sources, all of which are located in the Milky Way. In all cases, the aromatic C-D stretching feature is weaker than the aliphatic C-D stretching feature, and, in the case o...

  15. Polycyclic aromatic hydrocarbons with SPICA

    CERN Document Server

    Berne, O; Mulas, G; Tielens, A G G M; Goicoechea, J R

    2009-01-01

    Thanks to high sensitivity and 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 G$_0$/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 SPIC...

  16. Particle- and gas-phase emissions of polycyclic aromatic hydrocarbons from two-stroke, 50-cm 3 mopeds

    Science.gov (United States)

    Spezzano, Pasquale; Picini, Paolo; Cataldi, Dario; Messale, Fabrizio; Manni, Claudio

    2008-06-01

    The emissions of gas- and particle-phase polycyclic aromatic hydrocarbons (PAHs) were evaluated in the exhaust of 10 mopeds (4 EURO-0, 4 EURO-1 and 2 EURO-2) equipped with two-stroke engines with displacement of 50 cm3. Sampling was performed on a dynamometer bench both during the "cold-start" and the "hot" phases of the ECE-47 driving cycle. Eighteen PAHs were quantified and total PAH emission factors (∑PAH) ranged from 1790 to 15,059 μg km-1. Expressed in benzo(a)pyrene equivalent (BaPeq), emission factors ranged 4.7-86.3 μg km-1. PAH emissions are reduced according to the legislation class: EURO-0>EURO-1>EURO-2. PAH emission factors were greater during the cold-start phase than the hot phase of the ECE-47 cycle. Results show that despite their small engine size, two-stroke mopeds can emit amounts of particulate PAHs comparable or even higher than PAH emissions reported elsewhere from gasoline- and diesel-powered passenger cars and light- and heavy-duty vehicles.

  17. Emissions of Polycyclic Aromatic Hydrocarbons from Natural Gas Extraction into Air.

    Science.gov (United States)

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

    2016-07-19

    Natural gas extraction, often referred to as "fracking", has increased rapidly in the United States in recent years. To address potential health impacts, passive air samplers were deployed in a rural community heavily affected by the natural gas boom. Samplers were analyzed for 62 polycyclic aromatic hydrocarbons (PAHs). Results were grouped based on distance from each sampler to the nearest active well. Levels of benzo[a]pyrene, phenanthrene, and carcinogenic potency of PAH mixtures were highest when samplers were closest to active wells. PAH levels closest to natural gas activity were comparable to levels previously reported in rural areas in winter. Sourcing ratios indicated that PAHs were predominantly petrogenic, suggesting that PAH levels were influenced by direct releases from the earth. Quantitative human health risk assessment estimated the excess lifetime cancer risks associated with exposure to the measured PAHs. At sites closest to active wells, the risk estimated for maximum residential exposure was 0.04 in a million, which is below the U.S. Environmental Protection Agency's acceptable risk level. Overall, risk estimates decreased 30% when comparing results from samplers closest to active wells to those farthest from them. This work suggests that natural gas extraction is contributing PAHs to the air, at levels that would not be expected to increase cancer risk. PMID:27400263

  18. Emissions of Polycyclic Aromatic Hydrocarbons from Natural Gas Extraction into Air.

    Science.gov (United States)

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

    2016-07-19

    Natural gas extraction, often referred to as "fracking", has increased rapidly in the United States in recent years. To address potential health impacts, passive air samplers were deployed in a rural community heavily affected by the natural gas boom. Samplers were analyzed for 62 polycyclic aromatic hydrocarbons (PAHs). Results were grouped based on distance from each sampler to the nearest active well. Levels of benzo[a]pyrene, phenanthrene, and carcinogenic potency of PAH mixtures were highest when samplers were closest to active wells. PAH levels closest to natural gas activity were comparable to levels previously reported in rural areas in winter. Sourcing ratios indicated that PAHs were predominantly petrogenic, suggesting that PAH levels were influenced by direct releases from the earth. Quantitative human health risk assessment estimated the excess lifetime cancer risks associated with exposure to the measured PAHs. At sites closest to active wells, the risk estimated for maximum residential exposure was 0.04 in a million, which is below the U.S. Environmental Protection Agency's acceptable risk level. Overall, risk estimates decreased 30% when comparing results from samplers closest to active wells to those farthest from them. This work suggests that natural gas extraction is contributing PAHs to the air, at levels that would not be expected to increase cancer risk.

  19. Effects of biodiesel on emissions of regulated air pollutants and polycyclic aromatic hydrocarbons under engine durability testing

    International Nuclear Information System (INIS)

    An 80,000-km durability test was performed on two engines using diesel and biodiesel (methyl ester of waste cooking oil) as fuel in order to examine emissions resulting from the use of biodiesel. The test biodiesel (B20) was blended with 80% diesel and 20% methyl ester derived from waste cooking oil. Emissions of regulated air pollutants, including CO, HC, NOx, particulate matter (PM) and polycyclic aromatic hydrocarbons (PAHs) were measured at 20,000-km intervals. The identical-model engines were installed on a standard dynamometer equipped with a dilution tunnel used to measure the pollutants. To simulate real-world driving conditions, emission measurements were made in accordance with the United States Environmental Protection Agency (USEPA) FTP transient cycle guidelines. At 0 km of the durability test, HC, CO and PM emission levels were lower for the B20 engine than those for diesel. After running for 20,000 km and longer, they were higher. However, the deterioration coefficients for these regulated air pollutants were not statistically higher than 1.0, implying that the emission factors do not increase significantly after 80,000 km of driving. Total (gaseous+particulate phase) PAH emission levels for both B20 and diesel decreased as the driving mileage accumulated. However, for the engine using B20 fuel, particulate PAH emissions increased as engine mileage increased. The average total PAH emission factors were 1097 and 1437 μg bhp h-1 for B20 and diesel, respectively. For B20, the benzo[a]pyrene equivalence emission factors were 0.77, 0.24, 0.20, 7.48, 5.43 and 14.1 μg bhp h-1 for 2-, 3-, 4-, 5-, 6-ringed and total PAHs. Results show that B20 use can reduce both PAH emission and its corresponding carcinogenic potency. (author)

  20. Characteristics of polycyclic aromatic hydrocarbons and their gas/particle partitioning from fugitive emissions in coke plants

    Science.gov (United States)

    Mu, Ling; Peng, Lin; Liu, Xiaofeng; Song, Chongfang; Bai, Huiling; Zhang, Jianqiang; Hu, Dongmei; He, Qiusheng; Li, Fan

    2014-02-01

    Coking is one of the most important emission sources of polycyclic aromatic hydrocarbons (PAHs) in China. However, there is little information available on the emission characteristics of PAHs from fugitive emission during coking, especially on the specific processes dominating the gas-particle partitioning of PAHs. In this study, emission characteristics and gas-particle partitioning of PAHs from fugitive emission in four typical coke plants (CPs) with different scales and techniques were investigated. The average concentrations of total PAHs from fugitive emission at CP2, CP3 and CP4 (stamp charging) were 146.98, 31.82, and 35.20 μg m-3, which were 13.38-, 2.90- and 3.20-fold higher, respectively, than those at CP1 (top charging, 10.98 μg m-3). Low molecular weight PAHs with 2-3 rings made up 75.3% of the total PAHs on average, and the contributions of particulate PAH to the total BaP equivalent concentrations (BaPeq) in each plant were significantly higher than the corresponding contributions to the total PAH mass concentrations. The calculated total BaPeq concentrations varied from 0.19 to 10.86 μg m-3 with an average of 3.14 μg m-3, and more efficient measures to control fugitive emission in coke plants should be employed to prevent or reduce the health risk to workers. Absorption into organic matter dominated the gas-particle partitioning for most of the PAHs including PhA, FluA, Chr, BbF, BkF and BaP, while adsorption on elemental carbon appeared to play a dominant role for AcPy, AcP and Flu.

  1. Characterization of polycyclic aromatic hydrocarbon emissions in the particulate phase from burning incenses with various atomic hydrogen/carbon ratios

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Tzu-Ting, E-mail: d89844001@ntu.edu.tw [Department of Environmental Engineering and Health, Yuanpei University, No. 306, Yuanpei St., Hsin Chu, 300, Taiwan (China); Lin, Shaw-Tao [Department of Applied Chemistry, Providence University, 200 Chung-Chi Rd., Salu Dist., Taichung City 43301, Taiwan (China); Lin, Tser-Sheng [Department of Safety, Health, and Environmental Engineering, National United University, 2 Lien Da, Maioli, 360, Taiwan (China); Hong, Wei-Lun [Department of Environmental Engineering and Health, Yuanpei University, No. 306, Yuanpei St., Hsin Chu, 300, Taiwan (China)

    2012-01-01

    Polycyclic aromatic hydrocarbons in the particulate phase generated from burning various incense was investigated by a gas chromatography/mass spectrometry. Among the used incenses, the atomic H/C ratio ranged from 0.51 to 1.69, yielding the emission factor ranges for total particulate mass and PAHs of 4.19-82.16 mg/g and 1.20-9.50 {mu}g/g, respectively. The atomic H/C ratio of the incense was the key factor affecting particulate mass and the PAHs emission factors. Both the maximum emission factor and the slowest burning rate appear at the H/C ratio of 1.57. The concentrations of the four-ring PAHs predominated and the major species among the 16 PAHs were fluoranthene, phenanthrene, pyrene, and chrysene for most incense types. The benzo[a]pyrene, benzo[a]anthracene, benzo[b]fluoranthene, and dibenzo[a,h]anthracene accounted for 87.08-93.47% of the total toxic equivalency emission factor. - Highlights: Black-Right-Pointing-Pointer The atomic H/C ratio of incense was the key factor affecting PAHs emission factors. Black-Right-Pointing-Pointer Burning incense with lower atomic H/C ratio minimized the production of total PAHs. Black-Right-Pointing-Pointer The BaP, BaA, BbF, and DBA accounted for 87.08-93.47% of the TEQ emission factor. Black-Right-Pointing-Pointer Special PAH ratios were regarded as characteristic ratios for burning incense.

  2. Emission factors and particulate matter size distribution of polycyclic aromatic hydrocarbons from residential coal combustions in rural Northern China

    Science.gov (United States)

    Shen, Guofeng; Wang, Wei; Yang, Yifeng; Zhu, Chen; Min, Yujia; Xue, Miao; Ding, Junnan; Li, Wei; Wang, Bin; Shen, Huizhong; Wang, Rong; Wang, Xilong; Tao, Shu

    2010-12-01

    Coal consumption is one important contributor to energy production, and is regarded as one of the most important sources of air pollutants that have considerable impacts on human health and climate change. Emissions of polycyclic aromatic hydrocarbons (PAHs) from coal combustion were studied in a typical stove. Emission factors (EFs) of 16 EPA priority PAHs from tested coals ranged from 6.25 ± 1.16 mg kg -1 (anthracite) to 253 ± 170 mg kg -1 (bituminous), with NAP and PHE dominated in gaseous and particulate phases, respectively. Size distributions of particulate phase PAHs from tested coals showed that they were mostly associated with particulate matter (PM) with size either between 0.7 and 2.1 μm or less than 0.4 μm (PM 0.4). In the latter category, not only were more PAHs present in PM 0.4, but also contained higher fractions of high molecular weight PAHs. Generally, there were more than 89% of total particulate phase PAHs associated with PM 2.5. Gas-particle partitioning of freshly emitted PAHs from residential coal combustions were thought to be mainly controlled by absorption rather than adsorption, which is similar to those from other sources. Besides, the influence of fuel properties and combustion conditions was further investigated by using stepwise regression analysis, which indicated that almost 57 ± 10% of total variations in PAH EFs can be accounted for by moisture and volatile matter content of coal in residential combustion.

  3. Probing the Ionization States of Polycyclic Aromatic Hydrocarbons via the 15-20 {\\mu}m Emission Bands

    CERN Document Server

    Shannon, M J; Peeters, E

    2015-01-01

    We report new correlations between ratios of band intensities of the 15-20 {\\mu}m emission bands of polycyclic aromatic hydrocarbons (PAHs) in a sample of fifty-seven sources observed with Spitzer/IRS. This sample includes Large Magellanic Cloud point sources from the SAGE-Spec survey, nearby galaxies from the SINGS survey, two Galactic ISM cirrus sources and the spectral maps of the Galactic reflection nebulae NGC 2023 and NGC 7023. We find that the 16.4, 17.4 and 17.8 {\\mu}m band intensities are inter-correlated in all environments. In NGC 2023 and NGC 7023 these bands also correlate with the 11.0 and 12.7 {\\mu}m band intensities. The 15.8 {\\mu}m band correlates only with the 15-20 {\\mu}m plateau and the 11.2 {\\mu}m emission. We examine the spatial morphology of these bands and introduce radial cuts. We find that these bands can be spatially organized into three sets: the 12.7, 16.4 and 17.8 {\\mu}m bands; the 11.2, 15.8 {\\mu}m bands and the 15-18 {\\mu}m plateau; and the 11.0 and 17.4 {\\mu}m bands. We also f...

  4. Biodegradation of Polycyclic Aromatic Hydrocarbons

    OpenAIRE

    DEMİR, İsmail; DEMİRBAĞ, Zihni

    1999-01-01

    Polycylic aromatic hydrocarbons (PAHs), such as petroleum and petroleum derivatives, are widespread organic pollutants entering the environment, chiefly, through oil spills and incomplete combustion of fossil fuels. Since most PAHs are persist in the environment for a long period of time and bioaccumulate, they cause environmental pollution and effect biological equilibrium dramatically. Biodegradation of some PAHs by microorganisms has been biochemically and genetically investigated. Ge...

  5. Generation rates and emission factors of particulate matter and particle-bound polycyclic aromatic hydrocarbons of incense sticks.

    Science.gov (United States)

    Lung, Shih-Chun Candice; Hu, Shu-Chuan

    2003-02-01

    The generation rates and emission factors of particulate matter and associated polycyclic aromatic hydrocarbons (PAHs) from incense burning were assessed in a laboratory setting. The differences among different segments of the same stick, among different sticks of the same kind of incense, and between two kinds of manually made Chih-Chen incense sticks (A and B) were evaluated. Joss sticks were burned inside a 44 cm long elutriator; personal environmental monitors fitted into the top of the elutriator were used to take PM2.5 and PM10 samples of incense smoke. Samples were analyzed for PAHs by gas chromatography-flame ionization Detector. It was found that particle and associated PAHs were generated approximately at 561 microg/min (geometric standard deviation (GSD) = 1.1) and 0.56 microg/min (GSD = 1.1) from Incense A, and at 661 microg/min (GSD = 1.7) and 0.46 microg/min (GSD = 1.3) from Incense B, respectively. One gram of Incense A emitted about 19.8 mg (GSD = 1.1) particulate matter and 17.1 microg (GSD = 1.2) particulate-phase PAHs, while one gram of Incense B produced around 43.6 mg (GSD = 1.1) of particles and 25.2 microg (GSD = 1.2) of particle-bound PAHs. There were significant differences in emissions between Incenses A and B, although they belong to the same class of incense. A 10-20% variability in emissions was observed in the main part of the manually produced stick, and a larger variation was found at both tips of the combustible part.

  6. Exhaust emissions of polycyclic aromatic hydrocarbons, n-alkanes and phenols from vehicles coming within different European classes

    Science.gov (United States)

    Perrone, Maria Grazia; Carbone, Claudio; Faedo, Davide; Ferrero, Luca; Maggioni, Angela; Sangiorgi, Giorgia; Bolzacchini, Ezio

    2014-01-01

    EU emission standards for vehicles do not include many particulate (PM) and gaseous species, despite their considerable impact on air pollution and health. Emission factors (EFs) were measured for unregulated species, i.e. polycyclic aromatic hydrocarbons (PAHs) and n-alkanes (ALKs) in the particle phase, and, for the first time, EFs for phenols in both particle and gas phases. Exhaust samples were collected under controlled operating conditions (chassis dynamometer tests) for in-service vehicles (private cars, PCs and light duty vehicles, LDVs) from different EURO classes. EFs of trace organics were highest for the old EURO 1 vehicles (the tested EURO 1 vehicles were without emission-control devices), and lowest for the more recent EURO 3 and 4 vehicles. ALKs (C20-C32) were the most abundant trace organic compounds found in PM vehicle exhaust, and their EF ranged between 2034 and 101 μg km-1 (Euro 1-4 LDVs). PM-phased phenols EFs were in the range 0.42-2.50 μg km-1, and 4-nitrophenol was the most abundant one. The highest EFs were measured for phenols in the gas phase (dominated by the presence of phenol) for gasoline EURO 1 (43.16 ± 9.99 μg km-1). Emissions of PAHs changed depending on the fuel used. The PAH EFs of diesel-driven PCs were 4-5 times higher than those of gasoline vehicles, with PAHs diesel exhaust being mainly enriched in low 4-ring PAHs (85%), while 5-6 ring PAHs were prevalent (55%) in gasoline vehicles. Results of source profiles from chassis dynamometer tests were compared with ambient data, and the traffic PAH source profile derived from a tunnel study (Milan) agreed with the estimated emissions from a mix of diesel and gasoline vehicles circulating in the same area. Moreover, the impact of EURO regulatory changes on exhaust emissions was calculated, and this made it possible to estimate the downward trend of PAH emissions in the Province of Milan in the period 2005-2020.

  7. Characterization of polycyclic aromatic hydrocarbons in fugitive PM10 emissions from an integrated iron and steel plant.

    Science.gov (United States)

    Khaparde, V V; Bhanarkar, A D; Majumdar, Deepanjan; Rao, C V Chalapati

    2016-08-15

    Fugitive emissions of PM10 (particles <10μm in diameter) and associated polycyclic aromatic hydrocarbons (PAHs) were monitored in the vicinity of coking unit, sintering unit, blast furnace and steel manufacturing unit in an integrated iron and steel plant situated in India. Concentrations of PM10, PM10-bound total PAHs, benzo (a) pyrene, carcinogenic PAHs and combustion PAHs were found to be highest around the sintering unit. Concentrations of 3-ring and 4-ring PAHs were recorded to be highest in the coking unit whereas 5-and 6-ring PAHs were found to be highest in other units. The following indicatory PAHs were identified: indeno (1,2,3-cd) pyrene, dibenzo (a,h) anthracene, benzo (k) fluoranthene in blast furnace unit; indeno (1,2,3-cd) pyrene, dibenzo (a,h) anthracene, chrysene in sintering unit; Anthracene, fluoranthene, chrysene in coking unit and acenaphthene, fluoranthene, fluorene in steel making unit. Total-BaP-TEQ (Total BaP toxic equivalent quotient) and BaP-MEQ (Total BaP mutagenic equivalent quotient) concentration levels ranged from 2.4 to 231.7ng/m(3) and 1.9 to 175.8ng/m(3), respectively. BaP and DbA (dibenzo (a,h) anthracene) contribution to total-BaP-TEQ was found to be the highest. PMID:27099996

  8. A New Star-Formation Rate Calibration from Polycyclic Aromatic Hydrocarbon Emission Features and Application to High Redshift Galaxies

    CERN Document Server

    Shipley, Heath V; Rieke, George H; Brown, Michael J I; Moustakas, John

    2016-01-01

    We calibrate the integrated luminosity from the polycyclic aromatic hydrocarbon (PAH) features at 6.2\\micron, 7.7\\micron\\ and 11.3\\micron\\ in galaxies as a measure of the star-formation rate (SFR). These features are strong (containing as much as 5-10\\% of the total infrared luminosity) and suffer minimal extinction. Our calibration uses \\spitzer\\ Infrared Spectrograph (IRS) measurements of 105 galaxies at $0 < z < 0.4$, infrared (IR) luminosities of $10^9 - 10^{12} \\lsol$, combined with other well-calibrated SFR indicators. The PAH luminosity correlates linearly with the SFR as measured by the extinction-corrected \\ha\\ luminosity over the range of luminosities in our calibration sample. The scatter is 0.14 dex comparable to that between SFRs derived from the \\paa\\ and extinction-corrected \\ha\\ emission lines, implying the PAH features may be as accurate a SFR indicator as hydrogen recombination lines. The PAH SFR relation depends on gas-phase metallicity, for which we supply an empirical correction for...

  9. Emission, distribution and toxicity of polycyclic aromatic hydrocarbons (PAHs) during municipal solid waste (MSW) and coal co-combustion.

    Science.gov (United States)

    Peng, Nana; Li, Yi; Liu, Zhengang; Liu, Tingting; Gai, Chao

    2016-09-15

    Emission and distribution characteristics of polycyclic aromatic hydrocarbons (PAHs) were investigated during municipal solid waste (MSW) and coal combustion alone and MSW/coal blend (MSW weight fraction of 25%) co-combustion within a temperature range of 500°C-900°C. The results showed that for all combustion experiments, flue gas occupied the highest proportion of total PAHs and fly ash contained more high-ring PAHs. Moreover, the 3- and 4-ring PAHs accounted for the majority of total PAHs and Ant or Phe had the highest concentrations. Compared to coal, MSW combustion generated high levels of total PAHs with the range of 111.28μg/g-10,047.22μg/g and had high toxicity equivalent value (TEQ). MSW/coal co-combustion generated the smallest amounts of total PAHs and had the lowest TEQ than MSW and coal combustion alone. Significant synergistic interactions occurred between MSW and coal during co-combustion and the interactions suppressed the formation of PAHs, especially hazardous high-ring PAHs and decreased the TEQ. The present study indicated that the reduction of the yield and toxicity of PAHs can be achieved by co-combustion of MSW and coal. PMID:27265733

  10. Polycyclic aromatic hydrocarbons, elemental and organic carbon emissions from tire-wear.

    Science.gov (United States)

    Aatmeeyata; Sharma, Mukesh

    2010-09-15

    Tire-wear is an important source of PAHs, elemental carbon (EC) and organic carbon (OC). The emissions of these pollutants have been studied in an experimental set-up, simulating a realistic road-tire interaction (summer tire-concrete road). The large particle non-exhaust emissions (LPNE; diameter greater than 10 microm) have been evaluated over 14,500 km run of the tire. An increasing linear trend with cumulative km run was observed for emissions of PAHs and carbon. Amongst PAHs in LPNE, pyrene has been observed to be the highest (30+/-4 mg kg(-1)) followed by benzo[ghi]perylene (17+/-2 mg kg(-1)). Different fractions of EC-OC for tire-wear have been analyzed, and unlike exhaust emissions, EC1 was observed to be 99% of EC whereas more than 70% of the OC was the high temperature carbon (OC3 and OC4). The overall emission factors (mass tire(-1) km(-1)) for PAHs, EC and OC from tire-wear are 378 ng tire(-1) km(-1), 1.46 mg tire(-1) km(-1) and 2.37 mg tire(-1) km(-1) for small cars. PMID:20624631

  11. Polycyclic Aromatic Hydrocarbon emission in Spitzer/IRS maps I: Catalog and simple diagnostics

    CERN Document Server

    Stock, D J; Moya, L G V; Otaguro, J N; Sorkhou, S; Allamandola, L J; Tielens, A G G M; Peeters, E

    2016-01-01

    We present a sample of resolved galactic HII regions and photodissociation regions (PDRs) observed with the Spitzer infrared spectrograph (IRS) in spectral mapping mode between the wavelengths of 5--15 $\\mu$m. For each object we have spectral maps at a spatial resolution of $\\sim$4" in which we have measured all of the mid-infrared emission and absorption features. These include the PAH emission bands, primarily at 6.2, 7.7, 8.6, 11.2 and 12.7 $\\mu$m, as well as the spectral emission lines of neon and sulfur and the absorption band caused by silicate dust at around 9.8 $\\mu$m. In this work we describe the data in detail, including the data reduction and measurement strategies, and subsequently present the PAH emission band intensity correlations for each of the objects and the sample as a whole. We find that there are distinct differences between the sources in the sample, with two main groups, the first comprising the HII regions and the second the reflection nebulae (RNe). Three sources, the reflection nebu...

  12. [Simulation Study of the Emission of Polycyclic Aromatic Hydrocarbons and Sugar Alcohols from Biomass Burning].

    Science.gov (United States)

    Huang, Shuai; Huang, Xin-yi; Wu, Shui-ping; Hu, Qing-hua; Chen, Xiao-qiu

    2015-10-01

    To measure the emission factors of PM2.5 and its associated PAHs and sugar alcohols, Chinese red pine stick and four crop straw including rice, wheat, corn and cotton were burned in a chamber. In addition, the kinetics of certain compounds were obtained through the irradiation of the glass filters with PM2.5 loading by 500 W mercury lamp. The emission factors of PM2.5 were ranged from (2.26 ± 0.60) g x kg(-1) (Chinese red pine stick) to (14.33 ± 5.26) g x kg(-1) (corn straw). Although the emission factors of the total 19 PAHs differed from (0.82 ± 0.21) mg x kg(-1) (Chinese red pine stick) to (11.14 ± 5.69) mg x kg(-1) (cotton straw), 4 ring PAHs showed predominance over other PAHs accounting for 51% - 71% except Chinese red pine in which retene was the predominant compound. The emission factors of 9 sugar alcohols were ranged from (52.34 ± 50.16) mg x kg(-1) (rice straw) to (238.81 ± 33.62) mg x kg(-1) (wheat straw) with levoglucosan accounting for 72% - 96% of the total sugar alcohols. Both the selected PAHs and levoglucosan associated with PM2.5 followed the first order kinetics. The photolysis kinetic coefficient of PAHs (ring number ≥ 4) was decreased with the increase of PAHs loading in filters. Two PAHs source characteristic ratios such as Flua/( Flua + Py) and IP/(IP + BgP) were relative stable during the irradiation. The photolysis kinetic coefficient of levoglucosan (0.004 5 min(-1)) was comparable to benzo[a]anthracene (0.004 1 - 0.005 0 min(-1)). PMID:26841587

  13. Diurnal variations of residential particulate wood burning emissions and their contribution to the concentration of Polycyclic Aromatic Hydrocarbons (PAHs

    Directory of Open Access Journals (Sweden)

    L. Poulain

    2011-04-01

    Full Text Available Residential wood burning is becoming an increasingly important cause of air quality problems since it has become a popular source of alternative energy to fossil fuel. In order to characterize the contribution of residential wood burning to local particle pollution a field campaign was organized at the village of Seiffen (Saxony, Germany. During this campaign, an Aerosol Mass Spectrometer (AMS was deployed in parallel to a PM1 high volume filter sampler. The AMS mass spectra were analyzed using Positive Matrix Factorization (PMF to obtain detailed information about the organic aerosol (OA. Biomass-burning organic aerosol (BBOA, Hydrocarbon-like organic aerosol (HOA, Low-volatility oxygenated organic aerosol (LV-OOA and Semi-volatile oxygenated organic aerosol (SV-OOA were identified. Additionally, Polycyclic Aromatic Hydrocarbons (PAH were measured by the AMS and short term events of extremely high PAH concentration compared to the mean PAH value were observed during the whole measurement period. A comparison with the results from PM1 filter samples showed that the BBOA factor and the AMS PAH are good indicators of the total concentration of the different monosaccharide anhydrides and PAH measured on the filter samples. Based on its correlation with CO and the low car traffic, the HOA factor was considered to be related to residential heating using liquid fuel. A clear impact of the week and weekend days on the diurnal profiles of the different OA components was observed. The weekdays were characterized by two maxima; a first one early in the morning and a stronger one in the evening; during the weekend days, the different OA components principally reached one maxima early in the afternoon. Finally, the PAH emitted directly from residential wood combustion was estimated to represent 1.5% of the total mass of BBOA factor and around 62% of the total PAH concentration measured at Seiffen. This result highlights the important

  14. Spatial and temporal variations and mobile source emissions of polycyclic aromatic hydrocarbons in Quito, Ecuador

    International Nuclear Information System (INIS)

    Motor vehicles are a major source of air pollution in Quito, Ecuador; however, little work has been done to characterize spatial and temporal variations in traffic-related pollutants, or to measure pollutants in vehicle emissions. We measured PAH continuously for one year at two residential sites in Quito, and PAH and traffic patterns for one week near a busy roadway. Morning rush-hour traffic and temperature inversions caused daily PAH maxima between 06:00 and 08:00. SO2, NOx, CO, and PM2.5 behaved similarly. At the residential sites PAH levels during inversions were 2-3-fold higher than during the afternoon, and 10-16-fold higher than 02:00-03:00 when levels were lowest. In contrast, at the near-roadway site, PAH concentrations were 3-6-fold higher than at the residential sites, and the effects of inversions were less pronounced. Cars and buses accounted for >95% of PAH at the near-roadway site. Near-roadway PAH concentrations were comparable to other polluted cities. - Atmospheric temperature inversions and proximity to roadways strongly influence potential human exposure to ambient airborne PAH in Quito, Ecuador

  15. Emissions of polycyclic aromatic hydrocarbons (PAHs) from the pyrolysis of scrap tires

    Science.gov (United States)

    Chen, Shui-Jen; Su, Hung-Bin; Chang, Juu-En; Lee, Wen-Jhy; Huang, Kuo-Lin; Hsieh, Lien-Te; Huang, Yi-Chu; Lin, Wen-Yinn; Lin, Chih-Chung

    This work investigated the PAHs generated in a waste-tire pyrolysis process and the PAHs removal by a wet scrubber (WSB) and a flare. IND, DBA, and BaP were found to dominate in the powders of scrap tires before the pyrolysis. The PAHs in the carbon blacks formed in the pyrolysis were mainly 2-, 3-, 6-, and 7-ring PAHs. Nap was the most predominant water-phase PAH in the WSB effluent. About 40% of the water-phase total-PAHs in the WSB effluent were contributed by nine carcinogenic PAHs. NaP, IND, and COR displayed higher mean gas- and particulate-phase concentrations than the other PAHs in the flare exhaust. The mean removal efficiencies of individual PAHs, total-PAHs, and high carcinogenic BaP+IND+DBA were 39.1-90.4%, 76.2%, and 84.9%, respectively for the WSB. For the flare, the mean removal efficiencies of gaseous, particulate, and combined (gaseous+particulate) total-PAHs were 59.8%, 91.2%, and 66.8%, respectively, whereas the removal efficiencies were 91.0%, 80.1%, and 89.1%, respectively for the total-BaPeq. However, the gaseous BaA displayed a negative mean removal efficiency. The total PAH emission rate and factor estimated for the scrap tire pyrolysis plant were 42.3 g d -1 and 4.00 mg kg-tire -1, respectively.

  16. Mobile Laboratory Measurements of Black Carbon and Polycyclic Aromatic Hydrocarbon Emissions in Mexico City: A New Method for Motor Vehicle Emission Inventory Calculations

    Science.gov (United States)

    Jiang, M.; Marr, L. C.; Dunlea, E.; Herndon, S.; Jayne, J.; Rogers, T.; Knighton, B.; Zavala, M.; Molina, L. T.; Molina, M. J.

    2004-12-01

    Aerosol black carbon (BC) and polycyclic aromatic hydrocarbons (PAHs) are two products of carbonaceous fuel combustion that are of major concern for urban air quality and global climate change. As part of the Mexico City Metropolitan Area field campaign in April 2003 (MCMA-2003), a mobile laboratory drove throughout the city and chased vehicles to measure pollutants in their exhaust emissions. The laboratory is a van designed and built by Aerodyne Research, Inc. and is equipped with a suite of gas and particle analyzers, including an aethalometer that measures BC and a photoemission aerosol sensor that measures particle-bound PAHs. The main goal of this research is to determine fuel-based emission factors, or the mass of BC and PAH emitted per volume of fuel burned, for Mexico City¡_s vehicle fleet. We can then calculate the megacity¡_s emission inventory of these compounds, which is important on both the urban and global scales. In previous analyses, the mobile laboratory has been used to target emissions from specific vehicles. While chasing events can be analyzed to obtain emission factors for specific vehicles, data from the entire time period while the lab is driving through the streets, whether chasing individual vehicles or not, can also provide valuable information about mobile source emissions. The laboratory continuously samples ambient air from an inlet at the front of the van, and it is always ¡°seeing¡± exhaust plumes from the vehicles around it. This ¡°macroscopic¡± approach that considers all vehicles on the road, similar to tunnel and remote sensing studies, complements the ¡°microscopic¡± approach that focuses on individual vehicles. We have developed a method that automatically identifies exhaust plumes and quantifies emission factors from data collected by the mobile lab. While 200 individual chasing events were identified during the field campaign, over 40,000 exhaust plume points were identified using the macroscopic approach. The

  17. Birds and polycyclic aromatic hydrocarbons

    Science.gov (United States)

    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.

  18. Volatilisation of aromatic hydrocarbons from soil

    DEFF Research Database (Denmark)

    Lindhardt, B.; Christensen, T.H.

    1996-01-01

    The non-steady-state fluxes of aromatic hydrocarbons were measured in the laboratory from the surface of soils contaminated with coal tar Four soil samples from a former gasworks site were used for the experiments. The fluxes were quantified for 11 selected compounds, 4 mono- and 7 polycyclic...... aromatic hydrocarbons, for a period of up to 8 or 16 days. The concentrations of the selected compounds in the soils were between 0.2 and 3,100 mu g/g. The study included the experimental determination of the distribution coefficient of the aromatic hydrocarbons between the sorbed phase and the water under...... saturated conditions. The determined distribution coefficients showed that the aromatic hydrocarbons were more strongly sorbed to the total organic carbon including the coal tar pitch - by a factor of 8 to 25 - than expected for natural organic matter. The fluxes were also estimated using an analytical...

  19. Polycyclic aromatic hydrocarbons and nitropolycyclic aromatic hydrocarbons in particulates emitted by motorcycles

    International Nuclear Information System (INIS)

    We determined eleven PAHs and four NPAHs in particulates and regulated pollutants (CO, CO2, HC, NOx, PM) exhausted from motorcycles to figure out the characteristics of motorcycle exhausts. Fluoranthene and pyrene accounted for more than 50% of the total detected PAHs. Among four detected NPAHs, 6-nitrochrysene and 7-nitrobenz[a]anthracene were the predominant NPAHs and were highly correlated relationship with their parent PAHs (R = 0.93 and 0.97, respectively). The PM and HC emissions tended to be close to the PAH emissions. NOx and NPAHs were negatively correlated. Despite their small engine size, motorcycles emitted much more PM and PAHs, showed stronger PAH-related carcinogenicity and indirect-acting mutagenicity, but weaker NPAH-related direct-acting mutagenic potency than automobiles. This is the first study to analyze both PAHs and NPAHs emitted by motorcycles, which could provide useful information to design the emission regulations and standards for motorcycles such as PM. -- Highlights: ► We characterized PAHs and NPAHs distribution in motorcycle exhausts. ► NPAHs concentrations were about three orders of magnitude lower than those of PAHs. ► We found larger amounts of PM and PAHs in exhaust of motorcycles than of automobiles. ► Motorcycles showed stronger PAH-related toxicity than automobiles. ► Motorcycles showed weaker NPAH-related direct-acting mutagenicity than automobiles. -- Control polycyclic aromatic hydrocarbons and nitropolycyclic aromatic hydrocarbon in particulates emitted by motorcycles due to their toxic potency

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

    Directory of Open Access Journals (Sweden)

    Jovčić Nataša S.

    2013-01-01

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

  1. Attributing risk burden of PM2.5-bound polycyclic aromatic hydrocarbons to major emission sources: Case study in Guangzhou, south China

    Science.gov (United States)

    Yu, Qingqing; Gao, Bo; Li, Guanghui; Zhang, Yanli; He, Quanfu; Deng, Wei; Huang, Zhonghui; Ding, Xiang; Hu, Qihou; Huang, Zuzhao; Wang, Yujun; Bi, Xinhui; Wang, Xinming

    2016-10-01

    Polycyclic aromatic hydrocarbons (PAHs) have attracted an increasing concern in China's megacities. However, rare information is available on the spatial and seasonal variations of inhalation cancer risk (ICR) due to PAH exposure and their relations to specific sources. In this study, year-round PM2.5 samples were collected from 2013 to 2014 by high-volume samplers at four sites (one urban, two rural and one roadside station) in Guangzhou in the highly industrialized and densely populated Pearl River Delta (PRD) region and analyzed for 26 polycyclic aromatic hydrocarbons (PAHs) together with molecular tracers including levoglucosan, hopanes and elemental carbon. Higher molecular weight PAHs (5-ring or above) accounted for 64.3-87.5% of total PAHs. Estimated annual averages of benzo(a)pyrene-equivalent carcinogenic potency (BaPeq) were 1.37, 2.31 and 1.56 ng/m3 at urban SZ, rural JL and rural WQS, respectively, much higher than that at the roadside station YJ in an urban street canyon. ICR of PAHs in wintertime reached 2.2 × 10-4, nearly 3 times that in summer; and cancer risk of PAHs was surprisingly higher at the rural site than at other sites. Source contributions by positive matrix factorization (PMF) in the aid of molecular tracers revealed that overall coal combustion and biomass burning altogether contributed 73.8% of total PAHs and 85.2% of BaPeq, and particularly in winter biomass burning became the most significant source of total PAHs and BaPeq (51.8% and 52.5%), followed by coal combustion (32.0% and 39.1%) and vehicle emission (16.2% and 8.4%). The findings of this work suggest that even in China's megacities like Guangzhou, limiting biomass burning may benefit PAHs pollution control and cancer risk reduction.

  2. On-road traffic emissions of polycyclic aromatic hydrocarbons and their oxy- and nitro- derivative compounds measured in road tunnel environments.

    Science.gov (United States)

    Keyte, Ian J; Albinet, Alexandre; Harrison, Roy M

    2016-10-01

    Vehicular emissions are a key source of polycyclic aromatic compounds (PACs), including polycyclic aromatic hydrocarbons (PAHs) and their oxygenated (OPAH) and nitrated (NPAH) derivatives, in the urban environment. Road tunnels are a useful environment for the characterisation of on-road vehicular emissions, providing a realistic traffic fleet and a lack of direct sunlight, chemical reactivity and non-traffic sources. In the present investigation the concentrations of selected PAHs, OPAHs and NPAHs have been measured in the Parc des Princes Tunnel in Paris (PdPT, France), and at the Queensway Road Tunnel and an urban background site in Birmingham (QT, U.K). A higher proportion of semi-volatile (3-4 ring) PAH, OPAH and NPAH compounds are associated with the particulate phase compared with samples from the ambient environment. A large (~85%) decline in total PAH concentrations is observed between 1992 and 2012 measurements in QT. This is attributed primarily to the introduction of catalytic converters in the U.K as well as increasingly stringent EU vehicle emissions legislation. In contrast, NPAH concentrations measured in 2012 are similar to those measured in 1996. This observation, in addition to an increased proportion of (Phe+Flt+Pyr) in the observed PAH burden in the tunnel, is attributed to the increased number of diesel passenger vehicles in the U.K during this period. Except for OPAHs, comparable PAH and NPAH concentrations are observed in both investigated tunnels (QT and PdP). Significant differences are shown for specific substances between PAC chemical profiles in relation with the national traffic fleet differences (33% diesel passenger cars in U.K. vs 69% in France and up to 80% taking into account all vehicle categories). The dominating and sole contribution of 1-Nitropyrene observed in the PdPT NPAH profile strengthens the promising use of this compound as a diesel exhaust marker for PM source apportionment studies. PMID:27312273

  3. On-road traffic emissions of polycyclic aromatic hydrocarbons and their oxy- and nitro- derivative compounds measured in road tunnel environments.

    Science.gov (United States)

    Keyte, Ian J; Albinet, Alexandre; Harrison, Roy M

    2016-10-01

    Vehicular emissions are a key source of polycyclic aromatic compounds (PACs), including polycyclic aromatic hydrocarbons (PAHs) and their oxygenated (OPAH) and nitrated (NPAH) derivatives, in the urban environment. Road tunnels are a useful environment for the characterisation of on-road vehicular emissions, providing a realistic traffic fleet and a lack of direct sunlight, chemical reactivity and non-traffic sources. In the present investigation the concentrations of selected PAHs, OPAHs and NPAHs have been measured in the Parc des Princes Tunnel in Paris (PdPT, France), and at the Queensway Road Tunnel and an urban background site in Birmingham (QT, U.K). A higher proportion of semi-volatile (3-4 ring) PAH, OPAH and NPAH compounds are associated with the particulate phase compared with samples from the ambient environment. A large (~85%) decline in total PAH concentrations is observed between 1992 and 2012 measurements in QT. This is attributed primarily to the introduction of catalytic converters in the U.K as well as increasingly stringent EU vehicle emissions legislation. In contrast, NPAH concentrations measured in 2012 are similar to those measured in 1996. This observation, in addition to an increased proportion of (Phe+Flt+Pyr) in the observed PAH burden in the tunnel, is attributed to the increased number of diesel passenger vehicles in the U.K during this period. Except for OPAHs, comparable PAH and NPAH concentrations are observed in both investigated tunnels (QT and PdP). Significant differences are shown for specific substances between PAC chemical profiles in relation with the national traffic fleet differences (33% diesel passenger cars in U.K. vs 69% in France and up to 80% taking into account all vehicle categories). The dominating and sole contribution of 1-Nitropyrene observed in the PdPT NPAH profile strengthens the promising use of this compound as a diesel exhaust marker for PM source apportionment studies.

  4. Environmental dependence of polycyclic aromatic hydrocarbon emission at z~0.8. Investigation by observing the RX J0152.7-1357 with AKARI

    CERN Document Server

    Murata, Kazumi; Tanaka, Masayuki; Matsuhara, Hideo; Kodama, Tadayuki

    2015-01-01

    We study the environmental dependence of the strength of polycyclic aromatic hydrocarbon (PAH) emission by AKARI observations of RX J0152.7-1357, a galaxy cluster at z=0.84. PAH emission reflects the physical conditions of galaxies and dominates 8 um luminosity (L8), which can directly be measured with the L15 band of AKARI. L8 to infrared luminosity (LIR) ratio is used as a tracer of the PAH strength. Both photometric and spectroscopic redshifts are applied to identify the cluster members. The L15-band-detected galaxies tend to reside in the outskirt of the cluster and have optically green colour, R-z'~ 1.2. We find no clear difference of the L8/LIR behaviour of galaxies in field and cluster environment. The L8/LIR of cluster galaxies decreases with specific-star-formation rate divided by that of main-sequence galaxies, and with LIR, consistent with the results for field galaxies. The relation between L8/LIR and LIR is between those at z=0 and z=2 in the literature. Our data also shows that starburst galaxie...

  5. Dihydrodiol dehydrogenase and polycyclic aromatic hydrocarbon metabolism

    Energy Technology Data Exchange (ETDEWEB)

    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. Variations in the Peak Position of the 6.2 micron Interstellar Emission Feature: A Tracer of N in the Interstellar Polycyclic Aromatic Hydrocarbon Population

    Science.gov (United States)

    Hudgins, Douglas M.; Bauschlicher, Charles W.; Allamandola, L. J.

    2005-01-01

    This paper presents the results of an investigation of the molecular characteristics that underlie the observed peak position and profile of the nominal 6.2 micron interstellar emission band generally attributed to the CC stretching vibrations of polycyclic aromatic hydrocarbons (PAHs). It begins with a summary of recent experimental and theoretical studies ofthe spectroscopic properties of large (>30 carbon atoms) PAH cations as they relate to this aspect of the astrophysical problem. It then continues with an examination of the spectroscopic properties of a number of PAH variants within the context of the interstellar 6.2 micron emission, beginning with a class of compounds known as polycyclic aromatic nitrogen heterocycles (PANHs; PAHs with one or more nitrogen atoms substituted into their carbon skeleton). In this regard, we summarize the results of recent relevant experimental studies involving a limited set of small PANHs and their cations and then report the results of a comprehensive computational study that extends that work to larger PANH cations including many nitrogen-substituted variants of coronene(+) (C24H12(+)), ovalene(+) (C32H14(+)), circumcoronene(+) (C54H18(+)), and circum-circumcoronene(+) (C96H24(+)). Finally, we report the results of more focused computational studies of selected representatives from a number of other classes of PAH variants that share one or more of the key attributes of the PANH species studied. These alternative classes of PAH variants include (1) oxygen- and silicon-substituted PAH cations; (2) PAH-metal ion complexes (metallocenes) involving the cosmically abundant elements magnesium and iron; and (3) large, asymmetric PAH cations. Overall, the studies reported here demonstrate that increasing PAH size alone is insuEcient to account for the position of the shortest wavelength interstellar 6.2 micron emission bands, as had been suggested by earlier studies. On the other hand, this work reveals that substitution of one or

  7. Characterization of polycyclic aromatic hydrocarbon emissions in the particulate and gas phase from smoldering mosquito coils containing various atomic hydrogen/carbon ratios

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Tzu-Ting, E-mail: d89844001@ntu.edu.tw [Department of Environmental Engineering and Health, Yuanpei University, No. 306, Yuanpei St., Hsin Chu 30015, Taiwan (China); Lin, Shaw-Tao [Department of Applied Chemistry, Providence University, No. 200 Chung-Chi Rd., Salu Dist., Taichung City 43301, Taiwan (China); Lin, Tser-Sheng [Department of Safety, Health, and Environmental Engineering, National United University, 2 Lien Da, Maioli 360, Taiwan (China); Chung, Hua-Yi [Department of Environmental Engineering and Health, Yuanpei University, No. 306, Yuanpei St., Hsin Chu 30015, Taiwan (China)

    2015-02-15

    The polycyclic aromatic hydrocarbon emissions in particulate and gas phases generated from smoldering mosquito coils containing various atomic H/C ratios were examined. Five types of mosquito coils were burned in a test chamber with a total airflow rate of 8.0 L/min at a constant relative humidity and temperature. The concentrations of individual PAHs were determined using the GC/MS technique. Among the used mosquito coils, the atomic H/C ratio ranged from 1.23 to 1.57, yielding total mass, gaseous, and particulate PAH emission factors of 28.17–78.72 mg/g, 26,139.80–35,932.98 and 5735.22–13,431.51 ng/g, respectively. The various partitions of PAHs in the gaseous and particulate phases were in the ranges, 70.26–83.70% and 16.30–29.74% for the utilized mosquito coils. The carcinogenic potency of PAH emissions in the particulate phase (203.82–797.76 ng/g) was approximately 6.92–25.08 times higher than that of the gaseous phase (26.27–36.07 ng/g). Based on the analyses of PAH emissions, mosquito coils containing the lowest H/C ratio, a low oxygen level, and additional additives (i.e., CaCO{sub 3}) are recommended for minimizing the production of total PAH emission factors and carcinogenic potency. - Highlights: • PAHs emissions are influenced by mosquito coils containing various atomic H/C ratios. • The PAHs generated by burning mosquito coils mainly occur in the gaseous phase. • Total TEQ emission factors of PAHs mainly consisted of the particulate phase (> 87%). • The BaP and BaA accounted for 71.13–77.28% of the total TEQ emission factors. • Special PAH ratios were regarded as characteristic ratios for burning mosquito coil.

  8. Identification and quantification of known polycyclic aromatic hydrocarbons and pesticides in complex mixtures using fluorescence excitation-emission matrices and parallel factor analysis.

    Science.gov (United States)

    Ferretto, Nicolas; Tedetti, Marc; Guigue, Catherine; Mounier, Stéphane; Redon, Roland; Goutx, Madeleine

    2014-07-01

    Polycyclic aromatic hydrocarbons (PAHs) and pesticides are among the most widespread organic contaminants in aquatic environments. Because of their aromatic structure, PAHs and pesticides have intrinsic fluorescence properties in the ultraviolet/blue spectral range. In this study, excitation-emission matrix (EEM) fluorescence spectroscopy and parallel factor (PARAFAC) analysis were used to characterise and discriminate fluorescence signatures of nine PAHs and three pesticides at the μg L(-1) level in the presence of humic substances (0.1-10 mgCL(-1)). These contaminants displayed a diversity of fluorescence signatures regarding spectral position (λEx: 220-335 nm, λEm: 310-414 nm), Stokes shift (39-169 nm) and number of peaks (1-8), with detection limits ranging from 0.02 to 1.29μgL(-1). The EEM/PARAFAC method applied to mixtures of PAHs with humic substances validated a seven-component model that included one humic-like fluorophore and six PAH-like fluorophores. The EEM/PARAFAC method applied to mixtures of pesticides with humic substances validated a six-component model that included one humic-like fluorophore and three pesticide-like fluorophores. The EEM/PARAFAC method adequately quantified most of the contaminants for humic substance concentrations not exceeding 2.5 mg CL(-1). The application of this method to natural (marine) samples was demonstrated through (1) the match between the Ex and Em spectra of PARAFAC components and the Ex and Em spectra of standard PAHs, and (2) the good linear correlations between the fluorescence intensities of PARAFAC components and the PAH concentrations determined by GC-MS.

  9. Calculated molecular properties of polycyclic aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Hites, R.A.; Simonsick, W.J. Jr.

    1987-01-01

    This volume contains a compilation of calculated molecular properties for 272 polycyclic aromatic hydrocarbons (PAH) and monomethylated PAH, listed in sequence according to their increasing molecular weight. The Chemical Abstracts Registry number is also included for easy reference. The molecular properties were calculated using the semiempirical MDCO method with geometric optimization. These parameters include the heats of formation, the frontier orbital energies, the electronic and nuclear energies, the dipole moment, and the net atomic charges on each atom. The shape parameter and the length/breadth ratio from the optimized geometries is also computed.

  10. Polycyclic aromatic hydrocarbons (PAHs) in exhaust emissions from diesel engines powered by rapeseed oil methylester and heated non-esterified rapeseed oil

    Science.gov (United States)

    Vojtisek-Lom, Michal; Czerwinski, Jan; Leníček, Jan; Sekyra, Milan; Topinka, Jan

    2012-12-01

    Polycyclic aromatic hydrocarbons (PAHs) of exhaust emissions were studied in four direct-injection turbocharged four-cylinder diesel engines, with power ratings of 90-136 kW. The engines were operated on biodiesel (B-100), a blend of 30% biodiesel in diesel fuel (B-30), and heated rapeseed oil (RO) in two independent laboratories. Diesel particle filters (DPF) and selective catalytic reduction (SCR) systems were used with B-30 and B-100. Concentrations of individual PAHs sampled in different substrates (quartz, borosilicate fiber and fluorocarbon membrane filters, polyurethane foam) were analyzed using different methods. Benzo[a]pyrene toxic equivalents (BaP TEQ) were calculated using different sets of toxic equivalency factors (TEF). Operation on B-100 without aftertreatment devices, compared to diesel fuel, yielded a mean reduction in PAHs of 73%, consistent across engines and among TEF used. A lower PAH reduction was obtained using B-30. The BaP TEQ reductions on DPF were 91-99% using B-100, for one non-catalyzed DPF, and over 99% in all other cases. The BaP TEQ for heated RO were higher than those for B-100 and one half lower to over twice as high as that of diesel fuel. B-100 and RO samples featured, compared to diesel fuel, a relatively high share of higher molecular weight PAH and a relatively low share of lighter PAHs. Using different sets of TEF or different detection methods did not consistently affect the observed effect of fuels on BaP TEQ. The compilation of multiple tests was helpful for discerning emerging patterns. The collection of milligrams of particulate matter per sample was generally needed for quantification of all individual PAHs.

  11. Spatial variations of the 3 micron emission features within UV-excited nebulae - Photochemical evolution of interstellar polycyclic aromatic hydrocarbons

    International Nuclear Information System (INIS)

    Spectra at 3 microns have been obtained at several positions in the Orion Bar region and in the nebula surrounding HD 44179. Weak emission features at 3.40, 3.46, 3.51, and 3.57 microns are prominent in the Orion Bar region. The 3.40- and 3.51-micron features increase in intensity relative to the dominant 3.29-micron feature. The spectrum obtained in the Red Rectangle region 5 arcsecs north of HD 44179 are similar to those in the Orion Bar, with a weak, broad 3.40-micron feature at the position of HD 44179. The spatial behavior of the weak emission features is explained in terms of hot bands of the CH stretch and overtones, and combination bands of other fundamental vibrations in simple PAHs. Based on the susceptibility of PAHs to destruction by the far UV fields in both regions, PAH sizes are estimated at 20-50 carbon atoms. 38 refs

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

    Science.gov (United States)

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

    2009-02-01

    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 microg g(-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. PMID:18773130

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

    Energy Technology Data Exchange (ETDEWEB)

    Fu, S.; Li, K.; Xia, X.J.; Xu, X.B. [Chinese Academy of Sciences, Beijing (China)

    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.

  14. Exposure to polycyclic aromatic hydrocarbons with special focus on cancer

    Directory of Open Access Journals (Sweden)

    Thamaraiselvan Rengarajan

    2015-03-01

    Full Text Available Polycyclic aromatic hydrocarbons (PAHs are a group of compounds consisting of two or more fused aromatic rings. Most of them are formed during incomplete combustion of organic materials such as wood and fossil fuels, petroleum products, and coal. The composition of PAH mixtures varies with the source and is also affected by selective weathering effects in the environment. PAHs are ubiquitous pollutants frequently found in a variety of environments such as fresh water and marine sediments, the atmosphere, and ice. Due to their widespread distribution, the environmental pollution due to PAHs has aroused global concern. Many PAHs and their epoxides are highly toxic, mutagenic and/or carcinogenic to microorganisms as well as to higher forms of life including humans. The main aim of this review is to provide contemporary information on PAH sources, route of exposure, worldwide emission rate, and adverse effects on humans, especially with reference to cancer.

  15. Environmental Behavior, Sources, and Effects of Chlorinated Polycyclic Aromatic Hydrocarbons

    Directory of Open Access Journals (Sweden)

    Takeshi Ohura

    2007-01-01

    Full Text Available The environmental sources and behaviors of chlorinated 2- to 5-ring polycyclic aromatic hydrocarbons (ClPAHs. ClPAHs are ubiquitous contaminants found in urban air, vehicle exhaust gas, snow, tap water, and sediments. The concentrations of ClPAHs in each of these environments are generally higher than those of dioxins but markedly lower than the concentrations of the parent compounds, PAHs. Environmental data and emission sources analysis for ClPAHs reveal that the dominant process of generation is by reaction of PAHs with chlorine in pyrosynthesis. This secondary reaction process also occurs in aquatic environments. Certain ClPAHs show greater toxicity, such as mutagenicity and aryl hydrocarbon receptor activity, than their corresponding parent PAHs. Investigation of the sources and environmental behavior of ClPAHs is of great importance in the assessment of human health risks.

  16. Structural Evolution of Interstellar Polycyclic Aromatic Hydrocarbons

    Science.gov (United States)

    Hammonds, Mark; Candian, Alessandra; Mori, Tamami; Usui, Fumihiko; Onaka, Takashi

    2015-08-01

    Polycyclic Aromatic Hydrocarbons (PAHs) are an important reservoir for molecular carbon in the interstellar medium (ISM), and investigations into their chemistry and behaviour may be important to the understanding of how carbon is processed from simple forms into complex prebiotic molecules such as those detected in chondritic meteorites. In this study, infrared astronomical data from AKARI and other observatories are used together with laboratory and theoretical data to study variations in the structure of emitting PAHs in interstellar environments using spectroscopic decomposition techniques and bands arising from carbon-hydrogen bond vibrations at wavelengths from 3 - 14 microns. Results and inferences are discussed in terms of the processing of large carbonaceous molecules in astrophysical environments.

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

    Science.gov (United States)

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

    2015-01-01

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

  18. The discovery of a new infrared emission feature at 1905 wavenumbers (5.25 microns) in the spectrum of BD + 30 deg 3639 and its relation to the polycyclic aromatic hydrocarbon model

    Science.gov (United States)

    Allamandola, L. J.; Bregman, J. D.; Sandford, S. A.; Tielens, A. G. G. M.; Witteborn, F. C.

    1989-01-01

    A new IR emission feature at 1905/cm (5.25 microns) has been discovered in the spectrum of BD + 30 deg 3639. This feature joins the family of well-known IR emission features at 3040, 2940, 1750, 1610, '1310', 1160, and 890/cm. The origin of this new feature is discussed and it is assigned to an overtone or combination band involving C-H bending modes of polycyclic aromatic hydrocarbons (PAHs). Laboratory work suggests that spectral studies of the 2000-1650/cm region may be very useful in elucidating the molecular structure of interstellar PAHs. The new feature, in conjunction with other recently discovered spectral structures, suggests that the narrow IR emission features originate in PAH molecules rather than large carbon grains.

  19. High atmosphere-ocean exchange of semivolatile aromatic hydrocarbons

    Science.gov (United States)

    González-Gaya, Belén; Fernández-Pinos, María-Carmen; Morales, Laura; Méjanelle, Laurence; Abad, Esteban; Piña, Benjamin; Duarte, Carlos M.; Jiménez, Begoña; Dachs, Jordi

    2016-06-01

    Polycyclic aromatic hydrocarbons, and other semivolatile aromatic-like compounds, are an important and ubiquitous fraction of organic matter in the environment. The occurrence of semivolatile aromatic hydrocarbons is due to anthropogenic sources such as incomplete combustion of fossil fuels or oil spills, and other biogenic sources. However, their global transport, fate and relevance for the carbon cycle have been poorly assessed, especially in terms of fluxes. Here we report a global assessment of the occurrence and atmosphere-ocean fluxes of 64 polycyclic aromatic hydrocarbons analysed in paired atmospheric and seawater samples from the tropical and subtropical Atlantic, Pacific and Indian oceans. The global atmospheric input of polycyclic aromatic hydrocarbons to the global ocean is estimated at 0.09 Tg per month, four times greater than the input from the Deepwater Horizon spill. Moreover, the environmental concentrations of total semivolatile aromatic-like compounds were 102-103 times higher than those of the targeted polycyclic aromatic hydrocarbons, with a relevant contribution of an aromatic unresolved complex mixture. These concentrations drive a large global deposition of carbon, estimated at 400 Tg C yr-1, around 15% of the oceanic CO2 uptake.

  20. High atmosphere–ocean exchange of semivolatile aromatic hydrocarbons

    KAUST Repository

    González-Gaya, Belén

    2016-05-16

    Polycyclic aromatic hydrocarbons, and other semivolatile aromatic-like compounds, are an important and ubiquitous fraction of organic matter in the environment. The occurrence of semivolatile aromatic hydrocarbons is due to anthropogenic sources such as incomplete combustion of fossil fuels or oil spills, and other biogenic sources. However, their global transport, fate and relevance for the carbon cycle have been poorly assessed, especially in terms of fluxes. Here we report a global assessment of the occurrence and atmosphere-ocean fluxes of 64 polycyclic aromatic hydrocarbons analysed in paired atmospheric and seawater samples from the tropical and subtropical Atlantic, Pacific and Indian oceans. The global atmospheric input of polycyclic aromatic hydrocarbons to the global ocean is estimated at 0.09 Tg per month, four times greater than the input from the Deepwater Horizon spill. Moreover, the environmental concentrations of total semivolatile aromatic-like compounds were 10 2 -10 3 times higher than those of the targeted polycyclic aromatic hydrocarbons, with a relevant contribution of an aromatic unresolved complex mixture. These concentrations drive a large global deposition of carbon, estimated at 400 Tg C yr -1, around 15% of the oceanic CO2 uptake. © 2016 Macmillan Publishers Limited.

  1. Environmental Remediation: Removal of polycyclic aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Nkansah, Marian Asantewah

    2012-11-15

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous persistent semi-volatile organic compounds. They are contaminants that are resistant to degradation and can remain in the environment for long periods due to their high degree of conjugation, and aromaticity. PAHs are present in industrial effluents as products of incomplete combustion processes of organic compounds. Petroleum, coal and shale oil contain extremely complex mixtures of these PAHs, and their transport and refining process can also result in the release of PAHs. It is therefore prudent that such effluents are treated before discharge into the environment. In this project, different approaches to the treatment of PAHs have been investigated. Hydrous pyrolysis has been explored as a potential technique for degrading PAHs in water using anthracene as a model compound. The experiments were performed under different conditions of temperature, substrate, redox systems and durations. The conditions include oxidising systems comprising pure water, hydrogen peroxide and Nafion-SiO2 solid catalyst in water; and reducing systems of formic acid and formic acid / Nafion-SiO2 / Pd-C catalysts to assess a range of reactivities. Products observed in GCMS analysis of the extract from the water phase include anthrone, anthraquinone, xanthone and multiple hydro-anthracene derivatives (Paper I). In addition a modified version of the Nafion-SiO2 solid catalyst in water oxidising system was tested; and reducing systems of formic acid and formic acid / Nafion-SiO2 / Pd-C catalysts were adopted for the conversion of a mixture of anthracene, fluorene and fluoranthene. The rate of conversion in the mixture was high as compared to that of only anthracene (Paper II). Also the use of LECA (Lightweight expanded clay aggregates) as an adsorbent (Paper III) for PAHs (phenanthrene, fluoranthene and pyrene) removal from water has been.(Author)

  2. Selection of ionic liquids for the extraction of aromatic hydrocarbons from aromatic/aliphatic mixtures

    NARCIS (Netherlands)

    Meindersma, G. Wytze; Podt, Anita (J.G.); Haan, de André B.

    2005-01-01

    The separation of aromatic hydrocarbons (benzene, toluene, ethyl benzene and xylenes) from C4 to C10 aliphatic hydrocarbon mixtures is challenging since these hydrocarbons have boiling points in a close range and several combinations form azeotropes. In this work, we investigated the separation of t

  3. Real-time measurements of particulate matter and polycyclic aromatic hydrocarbon emissions from stationary combustion sources used in oil and gas production

    International Nuclear Information System (INIS)

    Particulate matter emissions and some components of the particles were measured in the exhaust from combustion equipment used in oil and gas production operations near Bakersfield, California. The combustion sources included a 22.5 MW (electric) turbine generator, a 342-Bhp rich-burn spark ignition engine, and a 50 million Btu/h steam generator, all fired using natural gas. The particle components and measurement techniques were as follows: (1) Calcium, magnesium, sodium, silicon, and iron were measured using laser-induced breakdown spectroscopy (LIBS), (2) particle-bound polycyclic aromatic hydrocarbons (PAH) were detected using the charge produced by photoionization, (3) particles having sizes between 0.1 and 7.5 (micro)m were counted using an instrument based on light scattering, and (4) total particulate matter was measured according to US EPA Method 5. Not all of the methods were applied to all of the sources. Measurements were also made in the ambient air near the combustion air inlets to the units, for comparison with the concentrations in the exhaust, but the inlet and outlet measurements were not done simultaneously. Calcium, sodium, and silicon were found in the exhaust from the steam generator at concentrations similar to those in the ambient air near the inlet to the burner. Sodium and silicon were observed in the engine exhaust at levels a factor of four higher than their concentrations in the air. The principal metal observed in the engine exhaust was calcium, a component of the lubricating oil, at a concentration of 11.6 (micro)g/m3. The air entering the gas turbine is filtered, so the average concentrations of metals in the turbine exhaust under steady operating conditions were even lower than in the air. During start-up following a shut-down to wash the turbine, silicon and iron were the major species in the stack, at concentrations of 6.4 and 16.2 (micro)g/m3, respectively. A possible source of silicon is the water injected into the turbine for

  4. Porphyrins Fused with Unactivated Polycyclic Aromatic Hydrocarbons

    KAUST Repository

    Diev, Vyacheslav V.

    2012-01-06

    A systematic study of the preparation of porphyrins with extended conjugation by meso,β-fusion with polycyclic aromatic hydrocarbons (PAHs) is reported. The meso-positions of 5,15-unsubstituted porphyrins were readily functionalized with PAHs. Ring fusion using standard Scholl reaction conditions (FeCl 3, dichloromethane) occurs for perylene-substituted porphyrins to give a porphyrin β,meso annulated with perylene rings (0.7:1 ratio of syn and anti isomers). The naphthalene, pyrene, and coronene derivatives do not react under Scholl conditions but are fused using thermal cyclodehydrogenation at high temperatures, giving mixtures of syn and anti isomers of the meso,β-fused porphyrins. For pyrenyl-substituted porphyrins, a thermal method gives synthetically acceptable yields (>30%). Absorption spectra of the fused porphyrins undergo a progressive bathochromic shift in a series of naphthyl (λ max = 730 nm), coronenyl (λ max = 780 nm), pyrenyl (λ max = 815 nm), and perylenyl (λ max = 900 nm) annulated porphyrins. Despite being conjugated with unsubstituted fused PAHs, the β,meso-fused porphyrins are more soluble and processable than the parent nonfused precursors. Pyrenyl-fused porphyrins exhibit strong fluorescence in the near-infrared (NIR) spectral region, with a progressive improvement in luminescent efficiency (up to 13% with λ max = 829 nm) with increasing degree of fusion. Fused pyrenyl-porphyrins have been used as broadband absorption donor materials in photovoltaic cells, leading to devices that show comparatively high photovoltaic efficiencies. © 2011 American Chemical Society.

  5. Structure-reactivity correlation of diesel soot and characterization of polycyclic aromatic hydrocarbons and carbonyls in biofuel emissions; Struktur-Reaktivitaets-Korrelation von Dieselruss und Charakterisierung von PAHs und Carbonylen im Abgas von Biokraftstoffen

    Energy Technology Data Exchange (ETDEWEB)

    Knauer, Markus

    2009-12-29

    This work reports on the determination of the structure-reactivity correlation of soot using Raman microscopy (RM) and temperature programmed oxidation (TPO), as well as on changes in the emission level of polycyclic aromatic hydrocarbons (PAH) and carbonyls at the combustion of biofuels. To characterize the reactivity of soot the combustion behaviour of model- and diesel soot has been determined by means of TPO in the presence of oxygen. In this context, spark-discharge soot and graphite powder were applied as model substances, and EURO VI and IV diesel soot as real-diesel soots. The structure of soot samples was investigated by RM and structural changes during the TPO were observed. In order to make a statement about the changes in PAH and carbonyl compound emissions during combustion of biofuels, samples were taken at different engine testbenches. Fossil fuel, biodiesel and vegetable oil were used during this study, as well as fuel mixtures with different biofuel fractions.

  6. Polycyclic aromatic hydrocarbons in sediments of China Sea.

    Science.gov (United States)

    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.

  7. Emissions of particulate matter and associated polycyclic aromatic hydrocarbons from agricultural diesel engine fueled with degummed,deacidified mixed crude palm oil blends

    Institute of Scientific and Technical Information of China (English)

    Khamphe Phoungthong; Surajit Tekasakul; Perapong Tekasakul; Gumpon Prateepchaikul; Naret Jindapetch; Masami Furuuchi; Mitsuhiko Hata

    2013-01-01

    Mixed crude palm oil (MCPO),the mixture of palm fiber oil and palm kernel oil,has become of great interest as a renewable energy source.It can be easily extracted from whole dried palm fruits.In the present work,the degummed,deacidified MCPO was blended in petroleum diesel at portions of 30% and 40% by volume and then tested in agricultural diesel engines for long term usage.The particulates from the exhaust of the engines were collected every 500 hr using a four-stage cascade air sampler.The 50% cut-off aerodynamic diameters for the first three stages were 10,2.5 and 1 μm,while the last stage collected all particles smaller than 1 μm.Sixteen particle bounded polycyclic aromatic hydrocarbons (PAHs) were analyzed using a high performance liquid chromatography.The results indicated that the size distribution of particulate matter was in the accumulation mode and the pattern of total PAHs associated with fine-particles (< 1 μm) showed a dominance of larger molecular weight PAHs (4-6 aromatic rings),especially pyrene.The mass median diameter,PM and total PAH concentrations decreased when increasing the palm oil content,but increased when the running hours of the engine were increased.In addition,Commercial petroleum diesel (PB0) gave the highest value of carcinogenic potency equivalent (BaPeq) for all particle size ranges.As the palm oil was increased,the BaPeq decreased gradually.Therefore the degummed-deacidified MCPO blends are recommended for diesel substitute.

  8. Partition of polycyclic aromatic hydrocarbons on organobentonites

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A series of organobentonites synthesized by exchanging organiccation 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 Foundation item: 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 2.621x105, 2.106x105, 2.247x104,5.085x104, 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 lgKoc and 1gkow, 1gKoc and 1gS for PAHs in the system of water

  9. Novel β-cyclodextrin modified quantum dots as fluorescent probes for polycyclic aromatic hydrocarbons (PAHs)

    Institute of Scientific and Technical Information of China (English)

    Cui Ping Han; Hai Bing Li

    2008-01-01

    Water-soluble CdSe/ZnS quantum dots (QDs)were prepared via a simple sonochemical procedure using β-cyclodextrin (CD)as surface coating agent.The QDs displayed a sensitive emission enhancement for anthracene over other related polycyclic aromatic hydrocarbons,and the detection limit was around 1.6 × 10-8 mol/L.

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

    NARCIS (Netherlands)

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

    2010-01-01

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

  11. Critical analysis of the local aromaticity concept in polyaromatic hydrocarbons.

    Science.gov (United States)

    Bultinck, Patrick

    2007-01-01

    A large number of local aromaticity indices for the benzenoid rings in polyaromatic hydrocarbons is computed. The results are interpreted, supporting Clar's hypothesis, and mutual correlations are investigated. It is shown that there are good correlations between all indices that strictly allow comparing benzenoid character. Poor correlations are found with NICS. A rationale is offered, yielding the conclusion that NICS and ring current maps follow a fundamentally different path to local aromaticity. In this sense the lack of correlation is not due to a real multidimensional character of aromaticity but rather to confusion and vagueness of the aromaticity concept. PMID:17328438

  12. Exposure to polycyclic aromatic hydrocarbons with special focus on cancer

    Institute of Scientific and Technical Information of China (English)

    Thamaraiselvan; Rengarajan; Peramaiyan; Rajendran; Natarajan; Nandakumar; Boopathy; Lokeshkumar; Palaniswami; Rajendran; Ikuo; Nishigaki

    2015-01-01

    Polycyclie aromatic hydrocarbons(PAHs) are a group of compounds consisting of two or more fused aromatic rings.Most of them are formed during incomplete combustion of organic materials such as wood and fossil fuels,petroleum products,and coal.The composition of PAH mixtures varies with the source and is also affected by selective weathering effects in the environment.PAHs are ubiquitous pollutants frequently found in a variety of environments such as fresh water and marine sediments,the atmosphere,and ice.Due to their widespread distribution,the environmental pollution due to PAHs has aroused global concern.Many PAHs and their epoxides are highly toxic,mutagenic and/or carcinogenic to microorganisms as well as to higher forms of life including humans.The main aim of this review is to provide contemporary information on PAH sources,route of exposure,worldwide emission rate,and adverse effects on humans,especially with reference to cancer.

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

    International Nuclear Information System (INIS)

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

  14. Comments on Coulomb pairing in aromatic hydrocarbons

    CERN Document Server

    Huber, D L

    2013-01-01

    Recently reported anomalies in the double-photonionization spectra of aromatic molecules such as benzene, naphthalene, anthracene and coronene are attributed to Coulomb-pair resonances of pi electrons.

  15. Measurement of Aromatic-hydrocarbons With the DOAS Technique

    OpenAIRE

    Axelsson, H; Eilard, A.; Emanuelsson, A.; Galle, B.; Edner, Hans; Ragnarson, P; Kloo, H

    1995-01-01

    Long-path DOAS (differential optical absorption spectroscopy) in the ultraviolet spectral region has been shown to be applicable for low-concentration measurements of light aromatic hydrocarbons. However, because of spectral interferences among different aromatics as well as with oxygen, ozone, and sulfur dioxide, the application of the DOAS technique for this group of components is not without problems. This project includes a study of the differential absorption characteristics, between 250...

  16. High-resolution gas chromatographic analysis of polycyclic aromatic hydrocarbons and aliphatic hydrocarbons

    International Nuclear Information System (INIS)

    A study of the analysis by gas chromatography of aromatic polycyclic hydrocarbons and aliphatic hydrocarbons is presented. The separation has been carried out by glass and fused silica capillary column in two different polar stationary phases OV-1 and SE-54. The limitation and the advantages of the procedure are discussed in terms of separation, sensitivity and precision. (Author) 20 refs

  17. Polycyclic aromatic hydrocarbon formation under simulated coal seam pyrolysis conditions

    Institute of Scientific and Technical Information of China (English)

    Liu Shuqin; Wang Yuanyuan; Wang Caihong; Bao Pengcheng; Dang Jinli

    2011-01-01

    Coal seam pyrolysis occurs during coal seam fires and during underground coal gasification.This is an important source of polycyclic aromatic hydrocarbon (PAH) emission in China.Pyrolysis in a coal seam was simulated in a tubular furnace.The 16 US Environmental Protection Agency priority controlled PAHs were analyzed by HPLC.The effects of temperature,heating rate,pyrolysis atmosphere,and coal size were investigated.The results indicate that the 3-ring PAHs AcP and AcPy are the main species in the pyrolysis gas.The 2-ring NaP and the 4-ring Pyr are also of concern.Increasing temperature caused the total PAH yield to go through a minimum.The lowest value was obtained at the temperature of 600 ℃ Higher heating rates promote PAH formation,especially formation of the lower molecular weight PAHs.The typical heating rate in a coal seam,5 ℃/min,results in intermediate yields of PAHs.The total PAHs yield in an atmosphere of N2 is about 1.81 times that seen without added N2,which indicates that an air flow through the coal seam accelerates the formation of PAHs.An increase in coal particle size reduces the total PAHs emission but promotes the formation of 5- and 6-ring PAHs.

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

    Science.gov (United States)

    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.

  19. The discovery of a new infrared emission feature at 1905 wavenumbers (5.25 microns) in the spectrum of BD +30 degrees 3639 and its relation to the polycyclic aromatic hydrocarbon model

    Science.gov (United States)

    Allamandola, L. J.; Bregman, J. D.; Sandford, S. A.; Tielens, A. G.; Witteborn, F. C.; Wooden, D. H.; Rank, D.

    1989-01-01

    We have discovered a new IR emission feature at 1905 cm-1 (5.25 microns) in the spectrum of BD +30 degrees 3639. This feature joins the family of well-known IR emission features at 3040, 2940, 1750, 1610, "1310," 1160, and 890 cm-1 (3.3, 3.4, 5.7, 6.2, "7.7," 8.6, and 11.2 microns). The origin of this new feature is discussed and it is assigned to an overtone or combination band involving C-H bending modes of polycyclic aromatic hydrocarbons (PAHs). Laboratory work suggests that spectral studies of the 2000-1650 cm-1 (5.0-6.1 microns) region may be very useful in elucidating the molecular structure of interstellar PAHs. The new feature, in conjunction with other recently discovered spectral structure, suggests that the narrow IR emission features originate in PAH molecules rather than large carbon grains. Larger species are likely to be the source of the broad underlying "plateaus" seen in many of the spectra.

  20. Polycyclic’ Aromatic Hydrocarbon Induced Intracellular Signaling and Lymphocyte Apoptosis

    DEFF Research Database (Denmark)

    Schneider, Alexander M.

    The aryl hydrocarbon (dioxin) receptor (AhR) is a transcription factor possessing high affinity to potent environmental pollutants, polycyclic aromatic hydrocarbons (PAH) and related halogenated hydrocarbons (e.g. dioxins). Numerous research attribute toxicity of these compounds to the receptor...... novel mechanistic explanations for the toxicity of the known compounds. Another unanswered question of the AhR biochemistry is,” Which factors do control the AhP expression and activity?” Using fibroblast model, the role of a cell cycle in maintaining the AhR level was evaluated. The results...

  1. Bioavailability of Polycyclic Aromatic Hydrocarbons in Soils and Sediments

    NARCIS (Netherlands)

    Cuypers, M.P.

    2001-01-01

    Polycyclic aromatic hydrocarbons (PAHs) constitute a group of priority pollutants which are of increasing environmental concern because of their adverse effects on humans, animals, and plants. Soils and sediments generally serve as a sink for PAHs, which leads to the accumulation of PAHs at contamin

  2. Degradation of polynuclear aromatic hydrocarbons by two strains of Pseudomonas.

    Science.gov (United States)

    Nwinyi, Obinna C; Ajayi, Oluseyi O; Amund, Olukayode O

    2016-01-01

    The goal of this investigation was to isolate competent polynuclear aromatic hydrocarbons degraders that can utilize polynuclear aromatic hydrocarbons of former industrial sites at McDoel Switchyard in Bloomington, Indiana. Using conventional enrichment method based on soil slurry, we isolated, screened and purified two bacterial species strains PB1 and PB2. Applying the ribotyping technique using the 16S rRNA gene analysis, the strains were assigned to the genus Pseudomonas (Pseudomonas plecoglossicida strain PB1 and Pseudomonas sp. PB2). Both isolates showed promising metabolic capacity on pyrene sprayed MS agar plates during the preliminary investigations. Using time course studies in the liquid cultures at calculated concentrations 123, 64, 97 and 94ppm for naphthalene, chrysene, fluroanthene and pyrene, P. plecoglossicida strain PB1 and Pseudomonas sp. PB2 showed partial utilization of the polynuclear aromatic hydrocarbons. Naphthalene was degraded between 26% and 40%, chrysene 14% and 16%, fluroanthene 5% and 7%; pyrene 8% and 13% by P. plecoglossicida strain PB1 and Pseudomonas sp. PB2 respectively. Based on their growth profile, we developed a model R(2)=1 to predict the degradation rate of slow polynuclear aromatic hydrocarbon-degraders where all the necessary parameters are constant. From this investigation, we confirm that the former industrial site soil microbial communities may be explored for the biorestoration of the industrial site. PMID:27245129

  3. Polycyclic aromatic hydrocarbons in air samples of meat smokehouses

    DEFF Research Database (Denmark)

    Hansen, Åse Marie; Olsen, I L; Poulsen, O M

    1992-01-01

    In a screening programme nine Danish meat smokehouses were randomly selected for measurements on concentration of airborne polycyclic aromatic hydrocarbons (PAH). A total of 23 stationary air samples were collected during the entire working period of the kiln either above the kiln doors or approx...

  4. Extraction Techniques for Polycyclic Aromatic Hydrocarbons in Soils

    OpenAIRE

    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 ...

  5. Interactions of polyhalogeneted aromatic hydrocarbons with thyroid hormone metabolism.

    NARCIS (Netherlands)

    Schuur, A.G.

    1998-01-01

    This thesis deals with the possible interactions of polyhalogenated aromatic hydrocarbons and/or their metabolites with thyroid hormone metabolism. This chapter summarizes firstly the effects of thyroid hormone on the induction of biotransformation enzymes by PHAHs. Secondly, the results on the inhi

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

    DEFF Research Database (Denmark)

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

    2015-01-01

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

  7. Biotransformation of polycyclic aromatic hydrocarbons in marine polychaetes

    DEFF Research Database (Denmark)

    Jørgensen, Anne; Giessing, Anders; Rasmussen, Lene Juel;

    2008-01-01

    Deposit-feeding polychaetes constitute the dominant macrofauna in marine environments that tend to be depositional centers for organic matter and contaminants. Polychaetes are known to accumulate polycyclic aromatic hydrocarbons (PAHs) from both particulate and dissolved phases but less is known...

  8. Polycyclic aromatic hydrocarbons in soils around Guanting Reservoir, Beijing, China

    NARCIS (Netherlands)

    Jiao, W.T.; Lu, Y.L.; Wang, T.Y.; Li, J.; Han, Jingyi; Wang, G.; Hu, W.Y.

    2009-01-01

    The concentrations of 16 polycyclic aromatic hydrocarbons ( 16PAHs) were measured by gas chromatography equipped with a mass spectrometry detector (GC-MS) in 56 topsoil samples around Guanting Reservior (GTR), which is an important water source for Beijing. Low to medium levels of PAH contamination

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

    Science.gov (United States)

    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.

  10. Near Infrared Spectra of Large Polycyclic Aromatic Hydrocarbons.

    Science.gov (United States)

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

    The widespread, mid-IR interstellar emission features at 3.3, 6.2, 7.7, 8.6, and 11.2 microns are generally attributed to vibrationally excited polycyclic aromatic hydrocarbons (PAHs). Since these features typcially originate from radiation-rich regions, it has been generally thought that UV photons must dominate the interstellar excitation process since PAHs have very strong UV absorption bands. However, observations have shown that lower energy photons can also pump the emission (Aitken and Roche, Uchida and Sellgren), raising questions about the PAH model. Although it has long been known that larger PAHs should absorb at longer wavelengths (e.g. Schutte et. al., Salama et al., Li and Draine) data was not available for the isolated, neutral and ionized PAHs of sizes comparable to those thought responsible for the interstellar emission features. Here the matrix-isolated near-IR (NIR) spectra (from 0.7 to 2.5 microns) are presented for the anions and cations of PAHs ranging in size from C34H16 to C50H22. These molecules are characterized by strong absorption bands in this region, bands that can account for the emission of the interstellar features from UV poor regions. These NIR PAH transitions could also contribute to the extinction curve associated with the diffuse interstellar medium. For example, band overlap, as expected from a mixture of PAHs, can contribute to the continuum. Overlapping broad bands could lead to slight undulations in the continuum reminiscent of the Very Broad Structure (VBS, e.g. Hayes et al.). Furthermore, as previously pointed out, individual PAH bands may contribute to the diffuse interstellar band (DIB) spectrum (e.g. Romanini)

  11. In situ biodegradation potential of aromatic hydrocarbons in anaerobic groundwaters

    Science.gov (United States)

    Acton, D. W.; Barker, J. F.

    1992-04-01

    Three types of experiments were conducted to assess the potential for enhancing the in situ biodegradation of nine aromatic hydrocarbons in anaerobic, leachate-impacted aquifers at North Bay, Ontario, and at Canada Forces Base Borden. Laboratory micrososms containing authentic aquifer material and groundwater from the North Bay site were amended with nitrate and glucose. No significant losses of aromatic hydrocarbons were observed compared to unamended controls, over a period of 187 days. A total of eight in situ biodegradation columns were installed in the North Bay and Borden aquifers. Remedial additions included electron acceptors (nitrate and sulphate) and primary substrates (acetate, lactate and yeast extract). Six aromatic hydrocarbons [toluene, ethylbenzene, m-xylene, o-xylene, cumene and 1,2,4-trimethylbenzene ( 1,2,4-TMB)] were completely degraded in at least one in situ column at the North Bay site. Only toluene was degraded in the Borden aquifer. In all cases, aromatic hydrocarbon attenuation was attributed to biodegradation by methanogenic and fermentative bacteria. No evidence of aromatic hydrocarbon degradation was observed in columns remediated with nitrate or primary substrates. A continuous forced gradient injection experiment with sulphate addition was conducted at the North Bay site over a period of 51 days. The concentration of six aromatic hydrocarbons was monitored over time in the injection wells and at piezometer fences located 2, 5 and 10 m downgradient. All compounds except toluene reached injection concentration between 14 and 26 days after pumping began, and showed some evidence of selective retardation. Toluene broke through at a subdued concentration (˜ 50% of injection levels), and eventually declined to undetectable levels on day 43. This attenuation was attributed to adaptation and biodegradation by anaerobic bacteria. The results from these experiments indicate that considerable anaerobic biodegradation of aromatic hydrocarbons in

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

    International Nuclear Information System (INIS)

    Highlights: • Contamination of sediment by PAHs and alkylated PAHs was investigated in Osaka Bay. • The major sources appeared to be pyrogenic or both pyrogenic and petrogenic. • PAH concentrations were remarkably high at a site near Kobe. • PAHs in Kobe may have been derived from the fire associated with the earthquake. - Abstract: 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

  13. Growth of fungi on volatile aromatic hydrocarbons

    NARCIS (Netherlands)

    Prenafeta Boldú, F.X.

    2002-01-01

    The present study aimed the better understanding of the catabolism of monoaromatic hydrocarbons by fungi. This knowledge can be used to enhance the biodegradation of BTEX pollutants. Fungi with the capacity of using toluene as the sole source of carbon and energy were isolated by enriching environme

  14. Correlation between atmospheric polycyclic aromatic hydrocarbons exposure and urinary hydroxyl metabolites of polycyclic aromatic hydrocarbons in elderly population in Tianjin

    Institute of Scientific and Technical Information of China (English)

    秦晓蕾

    2013-01-01

    Objective To identify suitable hydroxyl polycyclic aromatic hydrocarbons(OH-PAHs) for co-evaluation of internal exposure level of PAHs by simultaneous determination of a variety of OH-PAHs in urine. Methods The 24-h individual particulate matter and morning urine

  15. 蚊香燃烧过程中多环芳烃的排放特征%EMISSION CHARACTERISTICS OF POLYCYCLIC AROMATIC HYDROCARBONS FROM MOSQUITO COIL BURNING

    Institute of Scientific and Technical Information of China (English)

    周宏仓; 宋园园; 陆建刚; 李红双; 蔡华侠; 赵晓莉

    2009-01-01

    对3种类型蚊香(有烟蚊香、微烟蚊香和无烟蚊香)原料、灰烬及烟气样品经索式提取、K-D浓缩和硅胶层析纯化后,采用GC-MS分析其US EPA推荐的16种优控多环芳烃的含量.结果表明,有烟蚊香和微烟蚊香烟气中多环劳烃总含量高于原料中的含量,无烟蚊香则相反.有烟蚊香和微烟蚊香原料以3环和4环多环芳烃为主,无烟蚊香原料以2环和3环多环芳烃为主,3种类型蚊香灰烬和烟气中多环芳烃均以2环、3环和4环化合物为主.通过对比蚊香燃烧前、后样品中多环芳烃的毒性,发现同原料相比,有烟蚊香燃烧后烟气中多环芳烃的毒性显著增加,而微烟蚊香和无烟蚊香则明显减少.%For the determination of 16 priority-controlled polycyclic aromatic hydrocarbons(PAHs) recommended by US EPA in raw material, ash and smoke of three types of mosquito coils (smoke mosquito coil, micro-smoke mosquito coil and smokeless mosquito coil) by GC-MS, the samples were extracted in a Soxhlet extractor, concentrated in a K-D apparatus, and separated in a silica gel clean-up column. The results show that the total PAHs contents in the smoke are higher than those in the raw material for smoke and micro-smoke mosquito coils, while the status reverse for smokeless mosquito coil PAHs in the raw material of smoke and micro-smoke mosquito coils are dominated by 3-ring and 4-ring PAHs, while 2-ring and 3-ring PAHs are predominant in the raw material of smokeless mosquito coil. Both the ash samples and smoke samples of three mosquito coils are dominated by 2-ring, 3-ring and 4-ring PAHs. By comparison of toxic parameters between smoke and raw material of mosquito coils, the toxic equivalent of PAHs in the smoke increases obviously for smoke mosquito coil, while the status reverse for micro-smoke and smokeless mosquito coils.

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

    Science.gov (United States)

    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.

  17. Polycyclic aromatic hydrocarbon in urban soil from Beijing, China

    Institute of Scientific and Technical Information of China (English)

    LI Xing-hong; MA Ling-ling; LIU Xiu-fen; FU Shan; CHENG Hang-xin; XU Xiao-bai

    2006-01-01

    Polycyclic aromatic hydrocarbons (EPA-PAHs) in the urban surface soils from Beijing were determined using gas chromatography and mass spectrometry (GC-MS). It is significantly complementary for understanding the PAHs pollution in soil of integrated Beijing city on the basis of the information known in the outskirts. The total concentration of 16 EPA-PAH was from 0.467 to 5.470 μg/g and was described by the contour map. Compound profiles presented that the 4-, 5- and 6-ring PAHs were major compositions. The correlation analysis showed that PAHs have the similar source in the most sampling sites and BaP might be considered as the indicator of PAHs. Characteristic ratios of anthracene (An)/(An+ phenanthrene (Phe)), fluoranthene (Flu)/(Flu+pyrene (Pyr)) and benzo[a]pyrene (BaP)/benzo[g,h,i]perylene (BghiP) indicated that the PAHs pollutants probably mainly originated from the coal combustion and it was not negligible from vehicular emission. The level of PAHs in our study area was compared with other studies.

  18. Analysis of aliphatic and aromatic hydrocarbons in particulate matter in Madrid urban area

    International Nuclear Information System (INIS)

    Levels of n-alkanes and polycyclic aromatic hydrocarbons have been measured in the air particulate matter during six months, from January to June of 1987, in an urban area of Madrid. The hydrocarbons were collected on glass fiber filters by high volumen sampling. The extraction was carried out by Sohxlet and ultrasonic techniques. The extracts were clean-up on silicagel fractionation and the chromatographic analysis was performed by capillary column gas chromatographic. Final results are discussed as well as the immission values related to the possible emission sources. (Author)

  19. Exposure of iron foundry workers to polycyclic aromatic hydrocarbons

    DEFF Research Database (Denmark)

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

    1994-01-01

    Exposure to polycyclic aromatic hydrocarbons (PAHs) in foundry workers has been evaluated by determination of benzo(a)pyrene-serum albumin adducts and urinary 1-hydroxypyrene. Benzo(a)pyrene binding to albumin and 1-hydroxypyrene were quantitatively measured by enzyme linked immunosorbent assay...... (ELISA) and reverse phase high performance liquid chromatography (HPLC), respectively. 70 male foundry workers and 68 matched controls were investigated. High and low exposure groups were defined from breathing zone hygienic samples, consisting of 16 PAH compounds in particulate and gaseous phase. Mean...... than in smoking and non-smoking controls (0 (0-0.022) and 0 (0-0.010) mumol/mol creatinine). Dose-response relations between total PAH, pyrene, carcinogenic PAHs, and 1-hydroxypyrene for smokers, and polycyclic aromatic hydrocarbons adsorbed to dust for non-smokers are suggested. Exposure to PAHs...

  20. Frozen Hydrocarbon Particles of Cometary Halos as Carriers of Unidentified Emissions

    Indian Academy of Sciences (India)

    Irakli Simonia

    2005-12-01

    The possible nature of unidentified cometary emissions is under discussion. We propose a new model of the ice particles in cometary halos as a mixture of frozen polycyclic aromatic hydrocarbons and acyclic hydrocarbons.We describe principal properties of frozen hydrocarbon particles (FHPs) and suggest interpreting some of the unidentified cometary emission lines as the photoluminescence of FHPs. The results of comparative analysis are present.

  1. Polycyclic aromatic hydrocarbons in some grounded coffee brands.

    Science.gov (United States)

    Grover, Inderpreet Singh; Sharma, Rashmi; Singh, Satnam; Pal, Bonamali

    2013-08-01

    Potentially toxic 16 priority polycyclic aromatic hydrocarbons (PAHs) were determined in four brands of grounded coffee. Four to 13 PAHs were detected. Concentrations of total PAHs in different brands of coffee samples were in the range of 831.7-1,589.7 μg/kg. Benzo[a]pyrene (2A: probable human carcinogen) was found in Nescafe Premium whereas naphthalene (2B: possible human carcinogen) was found in all the samples of coffee. PMID:23242460

  2. Occurrence of fungi degrading aromatic hydrocarbons in activated sludge biocenoses

    Directory of Open Access Journals (Sweden)

    Anna Grabińska-Łoniewska

    2014-08-01

    Full Text Available A set of 21 strains of yeast-like microorganisms isolated from biocenoses of aerobic and anaerobic wastewater treatment systems were assayed for their ability to utilize aromatic hydrocarbons as a sole C-source. Basing on the achieved results, the highly biochemically active strains for application in enhancing of wastewaters and exhaust gases purification as well as soil bioremediation were selected.

  3. THE INFRARED SPECTROSCOPY OF NEUTRAL POLYCYCLIC AROMATIC HYDROCARBON CLUSTERS

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-10-10

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

  4. Polycyclic aromatic hydrocarbon (PAH) occurrence and remediation methods

    OpenAIRE

    Henner, Pascale; Schiavon, Michel; Morel, Jean-Louis; Lichtfouse, Eric

    1997-01-01

    International audience Polycyclic aromatic hydrocarbons (PAHs) are potentially mutagenic and carcinogenic substances occurring at various concentrations in atmosphere, soils, waters and sediments. PAHs, inherited both from natural and anthropogenic processes, are persistent organic pollutants (POP) due to their chemical stability and biodegradation resistance. The increase of road transportation, and of industrial and agricultural activities has led to a notable build up of PAH amounts in ...

  5. Interactions of polyhalogeneted aromatic hydrocarbons with thyroid hormone metabolism.

    OpenAIRE

    Schuur, A.G.

    1998-01-01

    This thesis deals with the possible interactions of polyhalogenated aromatic hydrocarbons and/or their metabolites with thyroid hormone metabolism. This chapter summarizes firstly the effects of thyroid hormone on the induction of biotransformation enzymes by PHAHs. Secondly, the results on the inhibition of thyroid hormone sulfation by hydroxylated metabolites of PHAH are summarized. Some conclusions and remarks on the overall implications of the results are given at the end of this chapter....

  6. Fog processing of polycyclic aromatic hydrocarbons (PAH)

    Science.gov (United States)

    Wang, Y.; Khadapkar, K.; Ehrenhauser, F. S.; Hutchings, J. W.; Wornat, M. J.; Valsaraj, K. T.; Herckes, P.

    2010-07-01

    Polyaromatic hydrocarbons (PAHs) are a class of organic species of concern for environmental and human health. The present work will present initial finding of a comprehensive study on the fate of PAHs in multiphase fog/cloud systems and across consecutive fog/smog cycles. Field observations were conducted in Fresno, CA in Winter 2010. Simultaneous measurements of gas phase, aerosol and fog PAH allowed to gain insights on the partitioning of PAH in a multiphase fog system. Partitioning results as well as temporal evolution of PAH concentrations across different phases will be discussed. Select known degradation products (oxy-PAH) from the processing of PAHs were also analyzed in the fog systems, although frequently their concentrations were close to or below detection limits, even in the polluted urban study setting. The field observations are complemented by laboratory investigations on the reactivity of PAH in fog systems, both heterogeneously and in the aqueous phase. Heterogeneously a novel reactor design is being tested to simulate fog systems and allow for repeat fog/smog cycles. A separate series of measurements investigated the processing of PAH in the aqueous phase in a solar simulator set-up.

  7. Laboratory studies of polycyclic aromatic hydrocarbons: the search for interstellar candidates

    CERN Document Server

    Joblin, C; Simon, A; Mulas, G

    2009-01-01

    Polycyclic Aromatic Hydrocarbons (PAHs) are considered as a major constituent of interstellar dust. They have been proposed as the carriers of the Aromatic Infrared Bands (AIBs) observed in emission in the mid-IR. They likely have a significant contribution to various features of the extinction curve such as the 220 nm bump,the far-UV rise and the diffuse interstellar bands. Emission bands are also expected in the far-IR, which are better fingerprints of molecular identity than the AIBs. They will be searched for with the Herschel Space Observatory. Rotational emission is also expected in the mm range for those molecules which carry significant dipole moments. Despite spectroscopic studies in the laboratory, no individual PAH species could be identified. This emphasises the need for an investigation on where interstellar PAHs come from and how they evolve due to environmental conditions: ionisation and dissociation upon UV irradiation, interactions with electrons, gas and dust. There is also evidence for PAH ...

  8. DISTRIBUTION AND CHARACTERIZATION OF POLYCYCLIC AROMATIC HYDROCARBON COMPOUNDS IN AIRBORNE PARTICULATES OF EAST ASIA

    Institute of Scientific and Technical Information of China (English)

    Yan Liu; Libin Liu; Jin-Ming Lin; Ning Tang; Kazuichi Hayakawa

    2006-01-01

    A review is presented on the distribution and characterization of polycyclic aromatic hydrocarbons (PAHs)and their derivatives, including nitro-PAHs and hydro-PAHs, on atmospheric particulates of East Asia. Generally, PAH compounds with two or three aromatic rings are released mainly into the gas phase, while those containing three or more aromatic rings are associated with particulate matter (PM) emission. Particle-associated PAHs are primarily adsorbed on fine particles, and little associated with coarse particles. Investigation into the concentration level of PAHs in different areas can serve not only to reflect the pollutant status and sources but also to lead to the formulation of control strategies.The results of the present study show that China has more severe PAH pollution than such East Asian countries as Japan and Korea.

  9. Estimation and characterization of polycyclic aromatic hydrocarbons from magnesium metallurgy facilities in China.

    Science.gov (United States)

    Nie, Zhiqiang; Yang, Yufei; Tang, Zhenwu; Liu, Feng; Wang, Qi; Huang, Qifei

    2014-11-01

    Field monitoring was conducted to develop a polycyclic aromatic hydrocarbon (PAH) emission inventory for the magnesium (Mg) metallurgy industry in China. PAH emissions in stack gas and fly/bottom ash samples from different smelting units of a typical Mg smelter were measured and compared. Large variations of concentrations, congener patterns, and emission factors of PAHs during the oxidation and reduction stages in the Mg smelter were observed. The measured average emission factor (166,487 μg/t Mg) was significantly higher than those of other industrial sources. Annual emission from Mg metallurgy in 2012 in China was estimated at 116 kg (514 g BaPeq) for PAHs. The results of this study suggest that PAH emission from Mg industries should be considered by local government agencies. These data may be helpful for understanding PAH levels produced by the Mg industry and in developing a PAH inventory.

  10. Novel Approach for Evaluating Secondary Organic Aerosol from Aromatic Hydrocarbons: SOA Yield and Chemical Composition

    Science.gov (United States)

    Li, Lijie; Tang, Ping; Nakao, Shunsuke; Qi, Li; Kacarab, Mary; Cocker, David

    2016-04-01

    Aromatic hydrocarbons account for 20%-30% of urban atmospheric VOCs and are major contributors to anthropogenic secondary organic aerosol (SOA). However, prediction of SOA from aromatic hydrocarbons as a function of structure, NOx concentration, and OH radical levels remains elusive. Innovative SOA yield and chemical composition evaluation approaches are developed here to investigate SOA formation from aromatic hydrocarbons. SOA yield is redefined in this work by adjusting the molecular weight of all aromatic precursors to the molecular weight of benzene (Yield'= Yieldi×(MWi/MWBenzene); i: aromatic hydrocarbon precursor). Further, SOA elemental ratio is calculated on an aromatic ring basis rather than the classic mole basis. Unified and unique characteristics in SOA formed from aromatic hydrocarbons with different alkyl groups (varying in carbon number and location on aromatic ring) are explored by revisiting fifteen years of UC Riverside/CE-CERT environmental chamber data on 129 experiments from 17 aromatic precursors at urban region relevant low NOx conditions (HC:NO 11.1-171 ppbC:ppb). Traditionally, SOA mass yield of benzene is much greater than that of other aromatic species. However, when adjusting for molecular weight, a similar yield is found across the 17 different aromatic precursors. More importantly, four oxygens per aromatic ring are observed in the resulting SOA regardless of the alkyl substitutes attached to the ring, which majorly affect H/C ratio in SOA. Therefore, resulting SOA bulk composition from aromatic hydrocarbons can be predicted as C6+nH6+2nO4 (n: alkyl substitute carbon number). Further, the dominating role of the aromatic ring carbons is confirmed by studying the chemical composition of SOA formed from the photooxidation of an aromatic hydrocarbon with a 13C isotopically labeled alkyl carbon. Overall, this study unveils the similarity in SOA formation from aromatic hydrocarbons enhancing the understanding of SOA formation from

  11. The formation of polycyclic aromatic hydrocarbons in evolved circumstellar environments

    CERN Document Server

    Cherchneff, Isabelle

    2010-01-01

    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-...

  12. Turn-On Fluorogenic and Chromogenic Detection of Small Aromatic Hydrocarbon Vapors by a Porous Supramolecular Host.

    Science.gov (United States)

    Hatanaka, Sou; Ono, Toshikazu; Hisaeda, Yoshiio

    2016-07-18

    Benzene, toluene, ethylbenzene, the isomers of xylene, and trimethylbenzene are harmful volatile organic compounds and pose risks to human health and the environment. However, there are currently no effective chemosensors for vapors of these compounds. A porous supramolecular host for turn-on fluorogenic and chromogenic detection of the vapors of small aromatic hydrocarbons is presented. The host was constructed from a naphthalenediimide derivative that was supramolecularly connected to tris(pentafluorophenyl)borane. The amorphous powder form of the host allowed for effective accommodation of vapors of small aromatic hydrocarbons, resulting in a guest-dependent fluorescence emission. Increases in the fluorescence yield of 76-, 46-, and 37-fold were observed with toluene, benzene, and m-xylene, respectively. Negligible responses were obtained with common organic solvents. This simple supramolecular host could be applied as a useful sensor of small aromatic hydrocarbon vapors. PMID:27224939

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

    Science.gov (United States)

    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. PMID:26728284

  14. Extraction Techniques for Polycyclic Aromatic Hydrocarbons in Soils

    Directory of Open Access Journals (Sweden)

    E. V. Lau

    2010-01-01

    Full Text Available 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.

  15. Polycylcic Aromatic Hydrocarbons (PAH's) in dense cloud chemistry

    OpenAIRE

    Wakelam, Valentine; Herbst, Eric

    2008-01-01

    Accepted to ApJ Virtually all detailed gas-phase models of the chemistry of dense interstellar clouds exclude polycyclic aromatic hydrocarbons (PAH's). This omission is unfortunate because from the few studies that have been done on the subject, it is known that the inclusion of PAH's can affect the gas-phase chemistry strongly. We have added PAH's to our network to determine the role they play in the chemistry of cold dense cores. In the models presented here, we include radiative attachm...

  16. Failure of hydrogenation in protecting polycyclic aromatic hydrocarbons from fragmentation

    CERN Document Server

    Gatchell, Michael; de Ruette, Nathalie; Chen, Tao; Giacomozzi, Linda; Nascimento, Rodrigo F; Wolf, Michael; Anderson, Emma K; Delaunay, Rudy; Viziano, Violaine; Rousseau, Patrick; Adoui, Lamri; Huber, Bernd A; Schmidt, Henning T; Zettergren, Henning; Cederquist, Henrik

    2015-01-01

    A recent study of soft X-ray absorption in native and hydrogenated coronene cations, C$_{24}$H$_{12+m}^+$ $m=0-7$, led to the conclusion that additional hydrogen atoms protect (interstellar) Polycyclic Aromatic Hydrocarbon (PAH) molecules from fragmentation [Reitsma et al., Phys. Rev. Lett. 113, 053002 (2014)]. The present experiment with collisions between fast (30-200 eV) He atoms and pyrene (C$_{16}$H$_{10+m}^+$, $m=0$, 6, and 16) and simulations without reference to the excitation method suggests the opposite. We find that the absolute carbon-backbone fragmentation cross section does not decrease but increases with the degree of hydrogenation for pyrene molecules.

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

    Science.gov (United States)

    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.

  18. Emission of polycyclic aromatic hydrocarbons (PAHs and benzene, toluene, ethylbenzene and xylene (BTEX from the furan moulding sands with addition of the reclaim

    Directory of Open Access Journals (Sweden)

    M. Holtzer

    2014-10-01

    Full Text Available In this paper, the results of decomposition of a moulding sand with furfuryl resin also on a quartz matrix and with additions of a reclaimed material, under industrial conditions, are presented. Investigations of the gases emission in the test foundry plant were performed according to the original method developed in the Faculty of Foundry Engineering, AGH UST. The dependence of the emitted PAHs and BTEX group substances and ignition losses on the reclaim fraction in a moulding sand are of a linear character of a very high correlation coefficient R2. On the bases of the derived equations, it is possible to determine the amount of the emitted hazardous substances from the moulding sand containing the known fraction of the reclaim.

  19. The Origins of Polycyclic Aromatic Hydrocarbons: Are They Everywhere?

    Science.gov (United States)

    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

  20. Thermal neutron cross-section libraries for aromatic hydrocarbons

    Science.gov (United States)

    Cantargi, F.; Granada, J. R.

    2010-08-01

    Solid phases of aromatic hydrocarbons, such as benzene, toluene, mesitylene and a 3:2 mixture by volume of mesitylene and toluene, were studied as potential moderator materials for a cold neutron source. Existing information on the (lattice) translational and rotational modes of the different molecular species was used to produce generalized frequency spectra; the latter included the internal vibrational modes which in turn involved the analysis of the weights of the different modes. Cross-section libraries were generated in ENDF and ACE formats for hydrogen bounded in those materials at several temperatures, and were used in Monte Carlo calculations to analyze their neutron production compared with standard cryogenic materials like liquid hydrogen and solid methane, the best moderators in terms of cold neutron production. In particular, cross-section libraries were generated at 20 K, which is a typical operating temperature for the majority of the existing cold neutron sources. It was found that those aromatic hydrocarbons produce neutron spectra which are slightly warmer than that of solid methane while presenting a high resistance to radiation, conforming in this way a new and advantageous alternative to traditional moderator materials.

  1. Characterization of polycyclic aromatic hydrocarbons from the diesel engine by adding light cycle oil to premium diesel fuel.

    Science.gov (United States)

    Lin, Yuan-Chung; Lee, Wen-Jhy; Chen, Chung-Bang

    2006-06-01

    Diesel fuels governed by U.S. regulations are based on the index of the total aromatic contents. Three diesel fuels, containing various fractions of light cycle oil (LCO) and various sulfur, total polyaromatic, and total aromatic contents, were used in a heavy-duty diesel engine (HDDE) under transient cycle test to assess the feasibility of using current indices in managing the emissions of polycyclic aromatic hydrocarbons (PAHs) from HDDE. The mean sulfur content in LCO is 20.8 times as much as that of premium diesel fuel (PDF). The mean total polyaromatic content in LCO is 28.7 times as much as that of PDF, and the mean total aromatic content in LCO is 2.53 times as much as that of PDF. The total polyaromatic hydrocarbon emission factors in the exhaust from the diesel engine, as determined using PDF L3.5 (3.5% LCO and 96.5% PDF), L7.5 (7.5% LCO and 92.5% PDF), and L15 (15% LCO and 85% PDF) were 14.3, 25.8, 44, and 101 mg L(-1), respectively. The total benzo(a)pyrene equivalent (BaPeq) emission factors in the exhaust from PDF, L3.5, L7.5, and L15 were 0.0402, 0.121, 0.219, and 0.548 mg L(-1), respectively. Results indicated that using L3.5 instead of PDF will result in an 80.4% and a 201% increase of emission for total PAHs and total BaPeq, respectively. The relationships between the total polyaromatic hydrocarbon emission factor and the two emission control indices, including fuel polyaromatic content and fuel aromatic content, suggest that both indices could be used feasibly to regulate total PAH emissions. These results strongly suggest that LCO used in the traveling diesel vehicles significantly influences PAH emissions.

  2. Interstellar polycyclic aromatic hydrocarbons and carbon in interplanetary dust particles and meteorites

    Science.gov (United States)

    Allamandola, L. J.; Sandford, S. A.; Wopenka, B.

    1987-01-01

    Raman spectra of interplanetary dust particles (IDPs) and meteorites containing material similar to polycyclic aromatic hydrocarbons (PAHs) show features that are similar in position and relative strength to interstellar IR emission features attributable to vibrational transitions in free molecular-sized PAHs. In addition, these spectra sometimes show red photoluminescence that has elsewhere been attributed to PAHs, and a part of the carbonaceous phase in IDPs and meteorites contain a degree of deuterium enrichment anticipated in small, free PAHs that are exposed to ISM UV radiation. These observations suggest that some of the IDPs' carbonaceous material may have been produced in circumstellar dust shells, and only slightly modified in interstellar space.

  3. Characteristics of wintertime polycyclic aromatic hydrocarbon assemblage in aerosol of the Southern Adriatic

    Science.gov (United States)

    Jovanović, V. Ž.; Pfendt, P. A.; Filipović, A. J.

    2007-09-01

    Features of polycyclic aromatic hydrocarbon (PAH) assemblage in aerosol samples collected from the atmosphere of Herceg Novi during the winter months of two successive years were studied. The results showed almost the same concentration profiles of identified PAHs for samples from the two periods analyzed, generally suggesting a similar origin. Diagnostic ratios indicated combustion of wood and coal, emissions from petrol and diesel engines, and dust resuspension as sources that predominantly contributed to the atmospheric PAH concentrations. Statistical analysis, principal component analysis (PCA) in particular, allowed us to identify the impact of meteorological parameters on PAH abundance.

  4. Emissions of hydrocarbons from combustion of biofuels

    International Nuclear Information System (INIS)

    Evaluations and measurements of emissions of hydrocarbons from power plants with a capacity exceeding 1 MW using biofuels (wood fuels and peat) have been studied in order to identify and quantify the emissions of incompletely combusted hydrocarbons. The influence of the type of fuel and the combustion technology applied were also studied, using literature references. The report summarizes monitoring results from a number of plants using biofuels. The reported emissions from the different plants can not be compared as they are relatively few and the test results have been obtained under various conditions using different methods of testing and analysis. The methods used are often poorly documented in the studied reports. Few investigations of emissions of hydrocarbons from plants in the range of 1 to 10 MW have been carried out. The plant and the technology used are important factors determining the amount and type of emissions of hydrocarbons. Larger temporary emissions can occur during start up, operational disturbances or when using fuel of inhomogeneous quality. In order to minimize the emissions the combustion process must be efficiently controlled, and a fuel of a hohogeneous quality must be used. The report also summarizes sampling and analysis methods used for monitoring emissions of hydrocarbons. (29 refs., 17 figs.)

  5. Partially oxidized polycyclic aromatic hydrocarbons show an increased bioavailability and biodegradability.

    NARCIS (Netherlands)

    Meulenberg, R.; Rijnaarts, H.H.M.; Doddema, H.J.; Field, J.A.

    1997-01-01

    Polycyclic aromatic hydrocarbons have a low water solubility and tend to adsorb on soil particles, which both result in slow bioremediation processes. Many microorganisms, known for their ability to degrade polycyclic aromatic hydrocarbons, only partially oxidize these compounds. White rot fungi, fo

  6. Polycyclic Aromatic Hydrocarbons: Are They a Problem in Processed Oil Shales?

    OpenAIRE

    Maase, David L.; Adams, V. Dean

    1983-01-01

    Organic residues from processed oil shales were characterisized with specific attention to polycyclic aromatic hydrocarbons (PAH). Oil shale development in the White River Basin (Utah and Colorado) was projected and hydrological and geological parameters pertinent to estimations of polycyclic aromatic hydrocarbons (PAH) flux were focused. Oil shale samples from the Union B, Paraho, and Tosco II processes were extr...

  7. Effect of fuel composition on poly aromatic hydrocarbons in particulate matter from DI diesel engine; Particulate chu no PAH ni oyobosu nenryo sosei no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, S.; Tatani, T.; Yoshida, H.; Takizawa, H.; Miyoshi, K.; Ikebe, H. [COSMO Research Institute, Tokyo (Japan)

    1997-10-01

    The effect of fuel composition on poly aromatic hydrocarbons (PAH) in particulate matter from DI diesel engine was investigated by using deeply desulfurized fuel and model fuel which properties are not interrelated. It was found that the deeply desulfurized fuel have effect on reducing PAH emissions. Furthermore, it was suggested that poly aromatics in the fuel affect PAH emissions and the influence of tri-aromatics in the fuel was promoted by the coexistence of mono-aromatics or naphthene. PAH formation scheme from each fuel component was proposed by chemical thermodynamic data. 4 refs., 8 figs., 3 tabs.

  8. 我国8种市售蚊香燃烧烟气中多环芳烃的排放特征%Emission Characteristics of Polycyclic Aromatic Hydrocarbons in the Smoke from Eight Mosquito Coils in Chinese Market

    Institute of Scientific and Technical Information of China (English)

    周宏仓; 宋园园; 陆建刚; 李红双; 马嫣; 蔡华侠; 赵晓莉

    2009-01-01

    利用GC-MS对8种具有代表性的市售蚊香燃烧烟气中16种列入美国环境保护署(US EPA)优先控制的多环芳烃(PAHs)进行分析. 结果表明:有烟蚊香烟气中16种优先控制的PAHs均有检出(6号蚊香除外),排放因子较大的化合物主要有萘、苊、二氢苊、菲和荧蒽;无烟蚊香烟气中仅检出10~11种,排放因子最大的化合物是菲,其次为萘;各种蚊香烟气中PAHs均以2~3环化合物为主,约占排放量的83.3%~98.0%. 同无烟蚊香相比,有烟蚊香烟气中PAHs的排放量较大,毒性也较高. 根据烟气中PAHs排放因子估算出一盘蚊香燃烧后烟气中苯并[a]芘排放量相当于燃烧4支香烟,PAHs排放量相当于燃烧8支香烟;蚊香燃烧后室内空气中ρ(PAHs)高达 1 486.60ng/m~3,其中ρ(苯并[a]芘)为8.07ng/m~3,超过其 (GB/T18883─2002)中的日均限值.%The GC-MS technique was applied to analyze 16 US EPA-recommend priority-controlled polycyclic aromatic hydrocarbons (PAHs) from the smoke of eight mosquito coils in Chinese market. The results showed that all 16 priority-controlled PAHs were detected in the smoke of all smoking mosquito coils with the exception of coil No.6. The emissions were characterized by the predominance of Nap, AcPy, AcP, Phe and FluA. Only 10-11 PAHs were detected in the smoke from smokeless mosquito coils, with the main contributors including Phe and NaP. Among all the coils, the concentration distribution of PAHs was dominated by 2-ringed and 3-ringed PAHs, accounting for about 83.3%-98.0%. It can be seen that the amount of total PAHs emission and total toxic equivalent of PAHs in the smoke from smoking mosquito coils is much higher than that from smokeless mosquito coils. Based on emission factors in the smoke, burning one mosquito coil would release the same amount of BaP as burning 4 cigarettes, and the total amount of PAHs emission from burning one mosquito coil would be as high as that released from burning 8 cigarettes

  9. Role of methyl group number on SOA formation from monocyclic aromatic hydrocarbons photooxidation under low-NOx conditions

    OpenAIRE

    Li, L.; Tang, P.; Nakao, S.; Chen, C.-L.; Cocker III, D. R.

    2016-01-01

    Substitution of methyl groups onto the aromatic ring determines the secondary organic aerosol (SOA) formation from the monocyclic aromatic hydrocarbon precursor (SOA yield and chemical composition). This study links the number of methyl groups on the aromatic ring to SOA formation from monocyclic aromatic hydrocarbons photooxidation under low-NOx conditions (HC/NO  >  10 ppbC : ppb). Monocyclic aromatic hydrocarbons with increasing numbers of methyl groups are systemat...

  10. Formation History of Polycyclic Aromatic Hydrocarbons in Galaxies

    CERN Document Server

    Seok, Ji Yeon; Asano, Ryosuke S

    2014-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are some of the major dust components in the interstellar medium (ISM). We present our evolution models for the abundance of PAHs in the ISM on a galaxy-evolution timescale. We consider shattering of carbonaceous dust grains in interstellar turbulence as the formation mechanism of PAHs while the PAH abundance can be reduced by coagulation onto dust grains, destruction by supernova shocks, and incorporation into stars. We implement these processes in a one-zone chemical evolution model to obtain the evolution of the PAH abundance in a galaxy. We find that PAH formation becomes accelerated above certain metallicity where shattering becomes efficient. For PAH destruction, while supernova shock is the primary mechanism in the metal-poor environment, coagulation is dominant in the metal-rich environment. We compare the evolution of the PAH abundances in our models with observed abundances in galaxies with a wide metallicity range. Our models reproduce both the paucity of PAH...

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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. PMID:26776034

  13. [Polycyclic aromatic hydrocarbons (PAH) in cereal breakfast products].

    Science.gov (United States)

    Ciemniak, Artur; Chrachol, Lucyna

    2008-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants formed by incomplete combustion (pyrolysis) of several organic materials. PAHs occur as complex mixtures, never as individual components. They are chemically stable and highly lipophilic in nature and occur as contaminants in different food categories: vegetables, fruit, cereals, oils and fats, especially barbecued and smoked food. The present study was carried out to determine 16 PAHs in cereal products: musli, corn, oats and barley flakes, and crunchy. The analytical procedure was based on alkaline digestion, extraction with n-hexane and cleaned up in a florisil cartridge. Chromatographic separation was performed using gas chromatography (HP 6890) coupled to mass spectrometry (HP 5973). The levels of PAHs in most samples were generally low and excepting one sample of bred varied between 4.2 to 169 microg/kg. Benzo[a]pyrene, was detected in all samples, at level 0.02 microg/kg to 16 microg/kg. PMID:19143427

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

    Science.gov (United States)

    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). PMID:26986946

  15. A Shape-Persistent Cryptand for Capturing Polycyclic Aromatic Hydrocarbons.

    Science.gov (United States)

    Zhang, Rui-Feng; Hu, Wen-Jing; Liu, Yahu A; Zhao, Xiao-Li; Li, Jiu-Sheng; Jiang, Biao; Wen, Ke

    2016-07-01

    A shape-persistent cryptand 1, containing two face-to-face oriented electron-deficient 2,4,6-triphenyl-1,3,5-triazine units separated by approximately 7 Å, and bridged by two rigid 1,8-naphthyridine linkers and a pentaethylene oxide loop, is created for capturing polycyclic aromatic hydrocarbons. Cryptand 1 formed 1:1 complexes with PAH guest molecules, such as phenanthrene (6), anthracene (7), pyrene (8), triphenylene (9), and tetraphene (10). The single-crystal structure of complex 6⊂1 revealed that 6 was included in the cavity of 1 via face-to-face π···π stacking interactions. Soaking crystalline 1 in a toluene solution of anthracene resulted in anthracene from the toluene solution being picked up by the crystalline solid of 1. PMID:27258531

  16. Removal of high-molecular weight polycyclic aromatic hydrocarbons

    Directory of Open Access Journals (Sweden)

    Ulrich Vasconcelos

    2011-01-01

    Full Text Available Alternatives for the removal of high-molecular weight polycyclic aromatic hydrocarbons (HWM-PAH from soil were tested by adding fertilizer or glycerol, as well as the combination of both. Experiments were carried out for 60 days in reactors containing a HWM-PAH-contaminated soil (8030 μg kg-1, accompanied by pH monitoring, humidity control and quantification of total heterotrophic bacteria and total fungus. Fertilizer addition removed 41.6% of HWM-PAH. Fertilizer and glycerol in combination removed 46.2%. When glycerol was added individually, degradation reached 50.4%. Glycerol also promoted the increase of degradation rate during the first 30 days suggesting the HMW-PAH removal occurred through cometabolic pathways.

  17. Magnetic instability and pair binding in aromatic hydrocarbon superconductors

    Science.gov (United States)

    Huang, Zhongbing; Zhang, Chao; Lin, Hai-Qing

    2012-01-01

    Understanding magnetism and electron correlation in many unconventional superconductors is essential to explore mechanism of superconductivity. In this work, we perform a systematic numerical study of the magnetic and pair binding properties in recently discovered polycyclic aromatic hydrocarbon (PAH) superconductors including alkali-metal-doped picene, coronene, phenanthrene, and dibenzopentacene. The π-electrons on the carbon atoms of a single molecule are modelled by the one-orbital Hubbard model, and the energy difference between carbon atoms with and without hydrogen bonds is taking into account. We demonstrate that the spin polarized ground state is realized for charged molecules in the physical parameter regions, which provides a reasonable explanation of local spins observed in PAHs. In alkali-metal-doped dibenzopentacene, our results show that electron correlation may produce an effective attraction between electrons for the charged molecule with one or three added electrons. PMID:23213358

  18. Modeling the fate of polynuclear aromatic hydrocarbons in the rhizosphere

    International Nuclear Information System (INIS)

    Polynuclear aromatic hydrocarbons (PAHs) are major contaminants associated with wastes from manufactured gas plants, wood treating operations, and petroleum refining; they are potentially carcinogenic and mutagenic. It has been known that vegetation can enhance the rate and extent of degradation of PAHs in contaminated soil. Plant roots release exudates capable of supplying carbon and energy to microflora for degrading PAHs. It has also been well established that the population of microorganisms in the rhizosphere is significantly greater than that in the non-vegetated soil; these microorganisms are apparently responsible for the enhanced biodegradation of PAHs. A model has been derived for describing the rate of disappearance of a non-aqueous phase contaminant in the rhizosphere, which takes into account dissolution, adsorption, desorption and biodegradation of the contaminant, without neglecting the size distribution of the organic-phase droplets; the rate of biodegradation is expressed in terms of the Monod kinetics. The model is validated with the available experimental data for pyrene

  19. Study on Aromatization of C6 Aliphatic Hydrocarbons on ZRP Zeolite Catalyst

    Institute of Scientific and Technical Information of China (English)

    Wang Yongjun; Xie Chaogang

    2004-01-01

    The performance of ZRP zeolite catalysts for aromatization of C6 aliphatic hydrocarbons was investigated in a pulsed microreactor. The influence of metal modified ZRP zeolites on aromatization reaction was also studied, coupled with comparison of aromatization tendencies of olefins, paraffins and paraffins with different degrees of chain branching. Test results had shown that the lower the silicon/aluminum ratio in the ZRP zeolite, the higher the aromatization reactivity of aliphatic hydrocarbons. Modification of ZRP zeolite by zinc and its zinc content had apparent impact on the yield and distribution of aromatics. The aromatization tendency of olefins was apparently better than paraffins, while the aromatization tendency of monomethyl paraffins was better than that of straight-chain paraffins with the exception of dimethyl paraffins, which had worse aromatization tendency because of their steric hindrance.

  20. Sorption of polycyclic aromatic hydrocarbons to polystyrene nanoplastic.

    Science.gov (United States)

    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.

  1. Accumulation of Trace Metals, Petroleum Hydrocarbons, and Polycyclic Aromatic Hydrocarbons in Marine Copepods from the Arabian Gulf

    OpenAIRE

    El-Din, N.M. Nour; Abdel-Moati, M. A. R.

    2001-01-01

    In this study, zooplankton samples were collected from the coastal waters of Qatar during winter and summer 1998 to assess the impact of growing industrialization on the bioaccumulation of trace metals, total petroleum hydrocarbons (TPHCs) and polycyclic aromatic hydrocarbons (PAHs) in copepods, the dominant zooplankton group and main food for fish in the Arabian Gulf.

  2. Biodegradation of polycyclic aromatic hydrocarbons by arbuscular mycorrhizal leek plants

    Energy Technology Data Exchange (ETDEWEB)

    Liu, A.; Dalpe, Y. [Agriculture Canada, Ottawa, ON (Canada). Grain and Oilseeds Branch

    2005-07-01

    A study was conducted to examine the response of arbuscular mycorrhizal fungi (AMF) on the degradation of polycyclic aromatic hydrocarbon (PAH), nutrient uptake, and leek growth under greenhouse conditions. This experiment included 3 mycorrhizal treatments, 2 microorganism treatments, 2 PAH chemicals, and 4 concentrations of PAHs. Plant growth was greatly reduced by the addition of anthracene or phenanthrene in soil, whereas mycorrhizal inoculation not only increased plant growth, but also enhanced uptake of nitrogen and phosphorus. PAH concentrations in soil was lowered through the inoculation of two different strains of the species G. intraradices and G. versiforme. In 12 weeks of pot cultures, anthracene and phenanthrene concentrations decreased for all 3 PAH levels tested. However, the reduced amount of phenanthrene in soil was greater than that of anthracene. The addition of a soil microorganism extract into pot cultures accelerated the PAH degradation. The inoculation of AMF in a hydrocarbon contaminated soil was shown to enhance PAHs soil decontamination. It was concluded that a soil colonized with AMF can not only improve plant growth but can also stimulate soil microflora abundance and diversity. AMF may therefore directly influence PAH soil decontamination through plant growth enhancement.

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

    Science.gov (United States)

    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.

  4. The C--H Stretching Features at 3.2--3.5 Micrometer of Polycyclic Aromatic Hydrocarbons with Aliphatic Sidegroups

    CERN Document Server

    Yang, Xuejuan; Glaser, Rainer; Zhong, Jianxin

    2016-01-01

    The so-called unidentified infrared emission (UIE) features at 3.3, 6.2, 7.7, 8.6, and 11.3 micrometer are ubiquitously seen in a wide variety of astrophysical regions. The UIE features are characteristic of the stretching and bending vibrations of aromatic hydrocarbon materials, e.g., polycyclic aromatic hydrocarbon (PAH) molecules. The 3.3 micrometer aromatic C--H stretching feature is often accompanied by a weaker feature at 3.4 micrometer. The latter 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 micrometer aromatic C--H feature to that of the 3.4 micrometer aliphatic C--H feature allows one to estimate the aliphatic fraction of the UIE carriers, provided that the intrinsic oscillator strengths of the 3.3 micrometer aromatic C--H stretch (A3.3) and the 3.4 micrometer aliphatic C--H stretch (A3.4) are known. While previous studies on the aliphatic fraction of the UIE carriers were mostly based on the A3.4...

  5. Application of thermal desorption to the development of a gas chromatographic/mass spectrometric method for the determination of toluene, chlorinated aromatic hydrocarbons, and 2,3,7,8-tetrachlorodibenzo-p-dioxin in combustion emissions.

    Science.gov (United States)

    Donaldson, John D; Grimes, Susan M; Mehta, Lina; Jafari, Ahmad J

    2003-01-01

    A fast and accurate analytical method, which uses commercially available adsorbents (Tenax TA, Carbotrap B and C, and Carbosieve S-III), was developed for the sampling and determination of aromatic hydrocarbons, chloroaromatic compounds, and 2,3,7,8-tetrachlorodibenzo-p-dioxin. The breakthrough volume data show that Carbotrap C has a good capacity for compounds of high molecular weight, whereas Carbosieve S-III and Tenax TA are efficient for volatile compounds. The organic components are thermally desorbed and transferred to a gas chromatograph/mass spectrometer. Importantly, thermal desorption avoids conventional solvent extraction procedures and also allows reuse of adsorbent tubes. Preliminary results for recovery of analytes from tubes packed with single adsorbent prove that a single-adsorbent bed is not capable of sampling a wide range of compounds. The best method to obtain the desired collection and desorption properties is to use adsorbent tubes containing several different materials. The results of optimization studies are summarized. PMID:12607738

  6. Determination of Polycyclic Aromatic Hydrocarbons in Automobile Exhaust by Means of High-Performance Liquid Chromatography with Fluorescence Detection

    DEFF Research Database (Denmark)

    Nielsen, Tom

    1979-01-01

    A chromatographic method has been developed and applied to the determination of polycyclic aromatic hydrocarbons (PAHs) in particulate matter in automobile exhaust, in petrols, and in crankcase oils. The PAHs were purified from other organic compounds by thin-layer chromatography, separated by high-performance...... liquid chromatography, and measured by means of on-line fluorescence detection. The identities of the PAHs were verified by comparing the emission spectra obtained by a stop-flow technique with those of standard PAHs...

  7. Inclusion of poly-aromatic hydrocarbon (PAH) molecules in a functionalized layered double hydroxide

    Indian Academy of Sciences (India)

    L Mohanambe; S Vasudevan

    2006-01-01

    The internal surface of an Mg-Al layered double hydroxide has been functionalized by anchoring carboxy-methyl derivatized -cyclodextrin cavities to the gallery walls. Neutral polyaromatic hydrocarbon (PAH) molecules have been included within the functionalized solid by driving the hydrophobic aromatic molecules from a polar solvent into the less polar interior of the anchored cyclodextrin cavities by a partitioning process. The optical (absorption and emission) properties of the PAH molecules included within the functionalized Mg-Al layered double hydroxide solid are similar to that of dilute solutions of the PAH in non-polar solvents. The unique feature of these hybrid materials is that they are thermally stable over a wide temperature range with their emission properties practically unaltered.

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

    Science.gov (United States)

    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

  9. Molecular catalytic hydrogenation of aromatic hydrocarbons and hydrotreating of coal liquids.

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Shiyong; Stock, L.M.

    1996-05-01

    This report presents the results of research on the development of new catalytic pathways for the hydrogenation of multiring aromatic hydrocarbons and the hydrotreating of coal liquids at The University of Chicago under DOE Contract No. DE-AC22-91PC91056. The work, which is described in three parts, is primarily concerned with the research on the development of new catalytic systems for the hydrogenation of aromatic hydrocarbons and for the improvement of the quality of coal liquids by the addition of dihydrogen. Part A discusses the activation of dihydrogen by very basic molecular reagents to form adducts that can facilitate the reduction of multiring aromatic hydrocarbons. Part B examines the hydrotreating of coal liquids catalyzed by the same base-activated dihydrogen complexes. Part C concerns studies of molecular organometallic catalysts for the hydrogenation of monocyclic aromatic hydrocarbons under mild conditions.

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

    Science.gov (United States)

    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 ...

  11. MONITORING POLYNUCLEAR AROMATIC HYDROCARBONS IN SEDIMENT POREWATER BY SPMD

    Institute of Scientific and Technical Information of China (English)

    朱亚先; 张勇; 庄一廷; Ka-FaiPoon; MichaelH.W.Lam; 洪华生; RudolfS.S.Wu

    2001-01-01

    A new mimic biological Semi-permeable Membrane Device (SPMD) introduced for sampling organic pollutants yielded satisfactory results when it was frrst used as a passive sampler to concentrate and determine 16 kinds of polynuclear aromatic hydrocarbons (PAHs) by means of capillary GC on an HP 5890 GC-FID in coastal sediment perewater. The concentration of PAHs in sediment porewater for naphthalene(N), acenaphthlene(AL), acenaphthene (AE), fluorene (F), phenaphthene(P), anthracene(A), fluoranthene(FA), pyrene(Py), benzo[a]anthracene(B[a]A), chrysene(Chr), benzo[b] fluor- anthene(B[b]F), benzo[k]fluoranthene(B[k]F), benzo[a]pyrene(B[a]P),indeno[1,2,3,-cd]-Pyrene(I[123]P), dibenz[a,h]anthracene(D[ab]A) and benzo[g,h,i] perylene(B[ghi]P) were:50.36, under detection limits(UD), 18.19, 8.41, 8.40, 1.44, UD, 8.01, 524.15, 168.47, 50.13,123.66, 63.48, 27.40, 82.04 and 58,81 ng/L, respectively.

  12. Polycyclic Aromatic Hydrocarbon Ionization Energy Lowering in Water Ices

    Science.gov (United States)

    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

  13. Fibrous adsorbent for removal of aqueous aromatic hydrocarbons.

    Science.gov (United States)

    Jung, Yong-Jun; Kiso, Yoshiaki; Oguchi, Tatsuo; Yamada, Toshiro; Takagi, Hiroo; Nishimura, Kazuyuki

    2007-01-01

    Bundles of a strongly hydrophobic fibrous material (p-phenylene-2,6-benzobisoxazole; PBO; Zylon) were employed as an adsorbent for the removal of aqueous aromatic compounds, because the PBO fibers are too rigid to be woven and did not entrap suspended solids. The removal performance for nine kinds of polyaromatic hydrocarbons (PAHs) and di-(2-ethylhexyl) phthalate (DEHP) was evaluated. PAHs and DEHP at initial concentrations of 50 microg L(-1) were removed at 72.5-99.9% and ca. 95%, respectively, although the removal efficiencies were affected by the phase ratio (fiber weight/solution volume). The logarithm of the partition coefficient (log K) for planar PAHs was linearly correlated with the logarithm of the n-octanol/water partition coefficient (log P), but nonplanar PAHs, such as cis-stilbene, p-terphenyl, and o-terphenyl, showed significantly lower adsorption performance. The adsorbed PAHs were not desorbed effectively with CH3CN, CH2Cl2, and toluene. On the other hand, DEHP was effectively desorbed with methanol.

  14. Polycyclic aromatic hydrocarbons in Dalian soils: distribution and toxicity assessment

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Z.; Chen, J.W.; Yang, P.; Qiao, X.L.; Tian, F. [Dalian University of Technology, Dalian (China). Dept. of Environmental Science & Technology

    2007-07-01

    Concentrations of 15 polycyclic aromatic hydrocarbons (PAHs) were measured in surface soils collected from Dalian, China, for examination of distributions and composition profiles and their potential toxicity. The sum of 15 PAHs ({Sigma} PAHs) ranged from 190 to 8595 ng g{sup -1} dry weight, and showed an apparent urban-suburban-rural gradient in both {Sigma} PAHs and composition profiles. Using hierarchical cluster analysis (HCA), the sampling sites were grouped into four clusters corresponding to traffic area, park/residential area, suburban and rural areas. The ratios of naphthalene (Nap) and fluorene (Fl) versus fluoranthene (Flu), pyrene (Pyr) and indeno(1,2,3-cd) pyrene (InP) in the four clusters provided evidence of local distillation. The diagnostic ratios indicated the prevalent PAH sources were petroleum combustion and coal combustion in Dalian, and a cross plot of diagnostic ratios distinguished the urban samples from suburban and rural ones. Toxic potency assessment of soil PAHs presented a good relationship with benzo(a) pyrene (BaP) levels, toxic equivalent concentrations based on BaP (TEQ(BaP)) and dioxin-like toxic equivalent concentrations (TEQ(TCDD)). The study highlights that BaP is a good indicator for assessing the potential toxicity of PAHs, and presents a promising toxicity assessment method for soil PAHs.

  15. Solubilization and biodegradation of polycyclic aromatic hydrocarbons in microemulsions

    Energy Technology Data Exchange (ETDEWEB)

    Wong, J.W.C.; Zhao, Z.Y.; Yang, J.; Wong, S.Y. [Hong Kong Baptist Univ., Hong Kong (China). Sino-Forest Applied Research Centre for Pearl River Delta Environment, Dept. of Biology

    2009-07-01

    This study investigated the feasibility of using microemulsions to enhance the biodegradation of polycyclic aromatic hydrocarbons (PAHs). Microemulsions are commonly used in soil washing as a means of enhancing the solubility of hydrophobic pollutants. The microemulsions were composed of Tween-80, 1-pentanol and linseed oil. Phenanthrene (PHE) was dissolved in dichloromethane and added to a glass vial. Microemulsions were added separately to the vials. A high performance liquid chromatograph (HPLC) was used to determine PHE concentrations. The vials were inoculated with an isolated PAH degradative bacterium Bacillus subtilis B-UM. Soil collected from abandoned shipyards in Hong Kong were then spiked with the mixtures and aged for 3 months. One way analysis of variance (ANOVA) analyses were conducted. Results of the study showed that a microemulsion composed of 0.4 Tween-80, 0.1 per cent 1-pentanol, and 0.05 linseed oil effectively enhanced the biodegradation of PHE in the aqueous phase. It was concluded that microemulsions can be used to remediate soils contaminated by PAHs. 26 refs., 2 tabs., 4 figs.

  16. Polycyclic aromatic hydrocarbons and pesticides in soil of Vojvodina

    Directory of Open Access Journals (Sweden)

    Pucarević Mira M.

    2004-01-01

    Full Text Available The paper deals with several groups of compounds that represent the most frequent pollutants of soil in the world. The paper also reviews results of long-term studies conducted at the Institute of Field and Vegetable Crops in Novi Sad on the residues of pesticides and polycyclic aromatic hydrocarbons (PAHs in the soil of the Vojvodina Province. The analyzed samples have been found to contain residues of persistent pesticides and their metabolites lindane and its metabolites 6,20 μg/kg, alachlor 3,56 μg/kg, aldrin 2,3 μg/kg, heptachlor epoxide 0,99 μg/kg, chlordane 3,82 μg/kg, DDT and its metabolites 10,77 μg/kg, dieldrin 2,04 μg/kg, endrin 3,57 μg/kg and endrin aldehyde 1,36 μg/kg. Soil samples from Novi Sad municipality contained 53,69 μg/kg of DDT and its metabolites. The values of atrazine ranged from 0,0005 to 0,8 mg/kg. The values of PAHs were 6,64 mg/kg in industrial soil, 4,93 mg/kg in agricultural soil, and 4,55 mg/kg and 5,48 mg/kg in the Novi Sad municipality. The lowest value, 0.83 mg/kg, was found for nonagricultural/nonindustrial soils.

  17. Polycyclic aromatic hydrocarbons and pesticides in milk powder.

    Science.gov (United States)

    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. PMID:27210498

  18. Some carcinogenic polycyclic aromatic hydrocarbons by photoacoustic spectroscopy

    Science.gov (United States)

    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.

  19. Fibrous adsorbent for removal of aqueous aromatic hydrocarbons.

    Science.gov (United States)

    Jung, Yong-Jun; Kiso, Yoshiaki; Oguchi, Tatsuo; Yamada, Toshiro; Takagi, Hiroo; Nishimura, Kazuyuki

    2007-01-01

    Bundles of a strongly hydrophobic fibrous material (p-phenylene-2,6-benzobisoxazole; PBO; Zylon) were employed as an adsorbent for the removal of aqueous aromatic compounds, because the PBO fibers are too rigid to be woven and did not entrap suspended solids. The removal performance for nine kinds of polyaromatic hydrocarbons (PAHs) and di-(2-ethylhexyl) phthalate (DEHP) was evaluated. PAHs and DEHP at initial concentrations of 50 microg L(-1) were removed at 72.5-99.9% and ca. 95%, respectively, although the removal efficiencies were affected by the phase ratio (fiber weight/solution volume). The logarithm of the partition coefficient (log K) for planar PAHs was linearly correlated with the logarithm of the n-octanol/water partition coefficient (log P), but nonplanar PAHs, such as cis-stilbene, p-terphenyl, and o-terphenyl, showed significantly lower adsorption performance. The adsorbed PAHs were not desorbed effectively with CH3CN, CH2Cl2, and toluene. On the other hand, DEHP was effectively desorbed with methanol. PMID:17585293

  20. Polycyclic aromatic hydrocarbons in Italian preserved food products in oil.

    Science.gov (United States)

    Sannino, Anna

    2016-06-01

    A method based on gas chromatography/ tandem mass spectrometry was used to assess levels of 16 EU priority polycyclic aromatic hydrocarbons (PAHs) in 48 preserved food products in oil including foods such as vegetables in oil, fish in oil and oil-based sauces obtained from the Italian market. The benzo[a]pyrene concentrations ranged from <0.04 to 0.40 µg kg(-1), and 72.9% of the samples showed detectable levels of this compound. The highest contamination level was observed for chrysene with three additional PAHs (benzo[a]anthracene, benzo[b]fluoranthene and benzo[c]fluorene) giving mean values higher than the mean value for benzo[a]pyrene. Chrysene was detected in all the samples at concentrations ranging from 0.07 to 1.80 µg kg(-1) (median 0.31 µg kg(-1)). The contamination expressed as PAH4 (sum of benzo(a)pyrene, chrysene, benzo(a)anthracene and benzo(b)fluoranthene), for which the maximum tolerable limit has been set by Commission Regulation (EU) No. 835/2011, varied between 0.10 and 2.94 µg kg(-1). PMID:26886159

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

    Science.gov (United States)

    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. PMID:26820781

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

    Science.gov (United States)

    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).

  3. Anharmonicity and infrared bands of Polycyclic Aromatic Hydrocarbon (PAH) molecules

    Science.gov (United States)

    Petrignani, Annemieke; Maltseva, Elena; Candian, Alessandra; Mackie, Cameron; Huang, Xinchuan; Lee, Timothy J.; Tielens, Alexander; Oomens, Jos; Buma, Wybren Jan

    2015-08-01

    We present a systematic laboratory study of the CH stretching region in Polycyclic Aromatic Hydrocarbon (PAH) molecules of different shapes and sizes to investigate anharmonic behaviour and address the reliability of the never-validated but universally accepted scaling factors employed in astronomical PAH models. At the same time, new anharmonic theoretical quantum chemistry studies have been performed with the software program Spectro using our experimental data as benchmark. We performed mass and conformational-resolved, high-resolution spectroscopy of cold (~10K) linear and compact PAH molecules starting with naphthalene (C10H8) in the 3-µm CH stretching region. Surprisingly, the measured infrared spectra show many more strong modes than expected. Measurements of the deuterated counterparts demonstrate that these bands are the result of Fermi Resonances. First comparisons with harmonic and anharmonic DFT calculations using Gaussian 09 show that both approximations are not able to reproduce in detail the observed molecular reality. The improved anharmonic calculations performed with Spectro now include the effects of Fermi resonances and have been applied to PAHs for the first time. The analysis of the experimental data is greatly aided by these new theoretical quantum chemistry studies. Preliminary assignments are presented, aided by comparison between the observed rotational contour and the symmetry of candidate bands.

  4. Multiphoton ionization mass spectrometry of nitrated polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Tang, Yuanyuan; Imasaka, Tomoko; Yamamoto, Shigekazu; Imasaka, Totaro

    2015-08-01

    In order to suppress the fragmentation and improve the sensitivity for determination of nitrated polycyclic aromatic hydrocarbons (NPAHs), the mechanism of multiphoton ionization was studied for the following representative NPAHs, 9-nitroanthracene, 3-nitrofluoranthene, and 1-nitropyrene. The analytes were extracted from the PM2.5 on the sampling filter ultrasonically, and were measured using gas chromatography/multiphoton ionization/time-of-flight mass spectrometry with a femtosecond tunable laser in the range from 267 to 405 nm. As a result, a molecular ion was observed as the major ion and fragmentation was suppressed at wavelengths longer than 345 nm. Furthermore, the detection limit measured at 345 nm was measured to be the subpicogram level. The organic compounds were extracted from a 2.19 mg sample of particulate matter 2.5 (PM2.5), and the extract was subjected to multiphoton ionization mass spectrometry after gas chromatograph separation. The background signals were drastically suppressed at 345 nm, and the target NPAHs, including 9-nitroanthracene and 1-nitropyrene, were detected, and their concentrations were determined to be 5 and 3 pg/m(3), respectively. PMID:26048831

  5. Photoinduced toxicity of sediment-bound polycyclic aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Greenberg, B.M.; Duxbury, C.L.; Marwood, C.A.; Huang, X.D.; Dixon, D.G. [Univ. of Waterloo, Ontario (Canada)

    1994-12-31

    Polycyclic aromatic hydrocarbons (PAHs) are known to be both mutagenic and toxic. Light, in particular UV irradiation, increases their toxicity. Since aquatic plants cannot avoid PAHs or light, they are at risk. However, the major loadings of PAHs are in sediment. In this study the authors examined the assimilation of both intact and photomodified labelled PAHs bound to a surrogate, sediment (sand) by the higher aquatic plant Lemna gibba L. G-3. They found that simulated solar radiation significantly promoted the release of PAHs from sand and their assimilation by Lemna, although assimilation from the solid phase was slower than for chemicals placed directly into the aqueous medium. Toxicity of PAHs bound to sand was then measured by exposing plants to the sand-chemical composite for 8 d. Plants were exposed to both visible and SSR light conditions during this period, and toxicity was measured as inhibition of growth, inhibition of photosynthesis (chlorophyll fluorescence induction) and chlorosis. All three endpoints indicated that PAHs bound to a sediment phase can express phototoxicity and that the effects are most strongly promoted by the UV region of the solar spectrum. The authors have now extended this work to probe the effects of UV-B and PAHs on chloroplast development, with the finding that both stresses inhibit development of the photosynthetic apparatus.

  6. Separation and analysis of aromatic hydrocarbons from two Chinese coals

    Institute of Scientific and Technical Information of China (English)

    DING Ming-jie; LI Wen-dian; XIE Rui-lun; ZONG Ying; CAI Ke-ying; PENG Yao-li; ZONG Zhi-min; XIE Rui-lun; WEI Xian-yong

    2008-01-01

    Separation and analysis of aromatic hydrocarbons (AHs) from coals is of considerable significance for both fuel and non-fuel use of the coals. In present work two Chinese bituminous coals were selected for separation of AHs by ultrasonic extraction with CS2 followed by column chromatography using hexane as eluent. A series of AHs were separated from the two coals and analyzed by GC/MS. FTIR was employed to characterize the raw coals and the extracted residues. The results of GC/MS analysis show that the separated AHs are mono- to tetracyclic arenes, among which the principle AHs are alkyl naphthalenes and phenanthrenes. Obvious differences in the composition and the structure of AHs exist between the two coals, i.e., the AHs from Tongting coal tend to be higher rings compared to those from Pingshuo coal both from the variety and from the abundance of the AHs. FFIR analysis shows that the raw and extracted coals are similar in terms of functional groups, suggesting that the composition and structure of CS extract, especially the AHs, from coals can be used to interpret the coal structure to some extent.

  7. Eisenia fetida increased removal of polycyclic aromatic hydrocarbons from soil

    International Nuclear Information System (INIS)

    The removal of phenanthrene, anthracene and benzo(a)pyrene added at three different concentrations was investigated with or without earthworms (Eisenia fetida) within 11 weeks. Average anthracene removal by the autochthonous micro-organisms was 23%, 77% for phenanthrene and 13% for benzo(a)pyrene, while it was 51% for anthracene, 47% for benzo(a)pyrene and 100% for phenanthrene in soil with earthworms. At 50 and 100 mg phenanthrene kg-1 E. fetida survival was 91% and 83%, but at 150 mg kg-1 all died within 15 days. Survival of E. fetida in soil amended with anthracene ≤1000 mg kg-1 and benzo(a)pyrene ≤150 mg kg-1 was higher than 80% and without weight loss compared to the untreated soil. Only small amounts of PAHs were detected in the earthworms. It was concluded that E. fetida has the potential to remove large amounts of PAHs from soil, but more work is necessary to elucidate the mechanisms involved. - Addition of earthworms, Eisenia fetida, accelara removal of polycyclic aromatic hydrocarbons from soil

  8. Threshold Energies for Single Carbon Knockout from Polycyclic Aromatic Hydrocarbons

    CERN Document Server

    Stockett, M H; Chen, T; de Ruette, N; Giacomozzi, L; Wolf, M; Schmidt, H T; Zettergren, H; Cederquist, H

    2015-01-01

    We have measured absolute cross sections for ultrafast (fs) single-carbon knockout from Polycyclic Aromatic Hydrocarbon (PAH) cations as functions of He-PAH center-of-mass collision energy in the range 10-200 eV. Classical Molecular Dynamics (MD) simulations cover this range and extend up to 10$^5$ eV. The shapes of the knockout cross sections are well described by a simple analytical expression yielding experimental and MD threshold energies of $E_{th}^{Exp}=32.5\\pm 0.4$ eV and $E_{th}^{MD}=41.0\\pm 0.3$ eV, respectively. These are the first measurements of knockout threshold energies for molecules isolated \\emph{in vacuo}. We further deduce semi-empirical (SE) and MD displacement energies --- \\emph{i.e.} the energy transfers to the PAH molecules at the threshold energies for knockout --- of $T_{disp}^{SE}=23.3\\pm 0.3$ eV and $T_{disp}^{MD}=27.0\\pm 0.3$ eV. The semi-empirical results compare favorably with measured displacement energies for graphene $T_{disp}=23.6$ eV [Meyer \\emph{et al.} Phys. Rev Lett. \\tex...

  9. Investigation of polycyclic aromatic hydrocarbons from coal gasification

    Institute of Scientific and Technical Information of China (English)

    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.

  10. Occupational exposure to Polycyclic Aromatic Hydrocarbons in wood dust

    Science.gov (United States)

    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.

  11. Occupational exposure to Polycyclic Aromatic Hydrocarbons in wood dust

    Energy Technology Data Exchange (ETDEWEB)

    Huynh, C K; Schuepfer, P; Boiteux, P, E-mail: chuynh@hospvd.c [Institute for Work and Health, rue du Bugnon 21, CH-1005 Lausanne (Switzerland)

    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 mug.g{sup -1} or ppm. During sanding operations, the PU varnish-impregnated wood produces 100 times more PAHs in dust than the unfinished wood.

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

    Energy Technology Data Exchange (ETDEWEB)

    Ping Sun; Panuwat Taerakul; Linda K. Weavers; Harold W. Walker [Ohio State University, Columbus, OH (United States). Department of Civil and Environmental Engineering and Geodetic Science

    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.

  13. Source and deposition of polycyclic aromatic hydrocarbons to Shanghai, China

    Institute of Scientific and Technical Information of China (English)

    Lili Yan; Xiang Li; Jianmin Chen; Xinjun Wang; Jianfei Du; Lin Ma

    2012-01-01

    Despite recent efforts to investigate the distribution and fate of polycyclic aromatic hydrocarbons (PAHs) in air,water,and soil,very little is known about their temporal change in wet deposition.As a result of increased attention to public health,a large-scale survey on the deposition flux and distribution of PAH contamination in rainwater was urgently conducted in Shanghai,China.In this study,163 rainwater samples were collected from six sites,and 15 PAH compounds were detected by the use of a simple solid phase microextraction (SPME) technique coupled with gas chromatography-mass spectrometry.The dominant PAH species monitored were naphthalene,phenanthrene,anthracene,and fluoranthene.The concentration of total PAHs per event was between 74 and 980 ng/L,with an average value of 481 ng/L,which is at the high end of worldwide figures.The annual deposition flux of PAHs in rainwater was estimated to be 4148 kg/yr in the Shanghai area,suggesting rainfall as a major possible pathway for removing PAHs from the atmosphere.Diagnostic analysis by the ratios of An/178 and F1/F1+Py suggested that combustion of grass,wood,and coal was the major contributor to PAHs in the Shanghai region.Back trajectory analysis also indicated that the pollutant sources could be from the southern part of China.

  14. Polycyclic aromatic hydrocarbons in Dalian soils: distribution and toxicity assessment.

    Science.gov (United States)

    Wang, Zhen; Chen, Jingwen; Yang, Ping; Qiao, Xianliang; Tian, Fulin

    2007-02-01

    Concentrations of 15 polycyclic aromatic hydrocarbons (PAHs) were measured in surface soils collected from Dalian, China, for examination of distributions and composition profiles and their potential toxicity. The sum of 15 PAHs (SigmaPAHs) ranged from 190 to 8595 ng g(-1) dry weight, and showed an apparent urban-suburban-rural gradient in both SigmaPAHs and composition profiles. Using hierarchical cluster analysis (HCA), the sampling sites were grouped into four clusters corresponding to traffic area, park/residential area, suburban and rural areas. The ratios of naphthalene (Nap) and fluorene (Fl) versus fluoranthene (Flu), pyrene (Pyr) and indeno(1,2,3-cd)pyrene (InP) in the four clusters provided evidence of local distillation. The diagnostic ratios indicated the prevalent PAH sources were petroleum combustion and coal combustion in Dalian, and a cross plot of diagnostic ratios distinguished the urban samples from suburban and rural ones. Toxic potency assessment of soil PAHs presented a good relationship with benzo(a)pyrene (BaP) levels, toxic equivalent concentrations based on BaP (TEQ(BaP)) and dioxin-like toxic equivalent concentrations (TEQ(TCDD)). The study highlights that BaP is a good indicator for assessing the potential toxicity of PAHs, and presents a promising toxicity assessment method for soil PAHs. PMID:17285163

  15. Polycylcic Aromatic Hydrocarbons (PAH's) in dense cloud chemistry

    CERN Document Server

    Wakelam, Valentine

    2008-01-01

    Virtually all detailed gas-phase models of the chemistry of dense interstellar clouds exclude polycyclic aromatic hydrocarbons (PAH's). This omission is unfortunate because from the few studies that have been done on the subject, it is known that the inclusion of PAH's can affect the gas-phase chemistry strongly. We have added PAH's to our network to determine the role they play in the chemistry of cold dense cores. In the models presented here, we include radiative attachment to form PAH-, mutual neutralization between PAH anions and small positively-charged ions, and photodetachment. We also test the sensitivity of our results to changes in the size and abundance of the PAH's. Our results confirm that the inclusion of PAH's changes many of the calculated abundances of smaller species considerably. In TMC-1, the general agreement with observations is significantly improved contrary to L134N. This may indicate a difference in PAH properties between the two regions. With the inclusion of PAH's in dense cloud c...

  16. Polycyclic aromatic hydrocarbons in insular and coastal soils of the Russian Arctic

    Science.gov (United States)

    Abakumov, E. V.; Tomashunas, V. M.; Lodygin, E. D.; Gabov, D. N.; Sokolov, V. T.; Krylenkov, V. A.; Kirtsideli, I. Yu.

    2015-12-01

    The content and individual component compositions of polycyclic aromatic hydrocarbons in polar soils of the Russian Arctic sector have been studied. The contamination of soils near research stations is identified from the expansion of the range of individual polycyclic aromatic hydrocarbons, the abrupt increase in the content of heavy fractions, and the accumulation of benzo[ a]pyrene. Along with heavy hydrocarbons, light hydrocarbons (which are not only natural compounds, but also components of organic pollutants) are also accumulated in the contaminated soils. Heavy polycyclic aromatic hydrocarbons are usually of technogenic origin and can serve as markers of anthropogenic impact in such areas as Cape Sterligov, Cape Chelyuskin, and the Izvestii TsIK Islands. The content of benzo[ a]pyrene, the most hazardous organic toxicant, appreciably increases in soils around the stations, especially compared to the control; however, the level of MPC is exceeded only for the soils of Cape Chelyuskin.

  17. Magnetic graphene oxide as adsorbent for the determination of polycyclic aromatic hydrocarbon metabolites in human urine.

    Science.gov (United States)

    Zhu, Linli; Xu, Hui

    2014-09-01

    Detection of monohydroxy polycyclic aromatic hydrocarbons metabolites in urine is an advisable and valid method to assess human environmental exposure to polycyclic aromatic hydrocarbons. In this work, novel Fe3O4/graphene oxide composites were prepared and their application in the magnetic solid-phase extraction of monohydroxy polycyclic aromatic hydrocarbons in urine was investigated by coupling with liquid chromatography and mass spectrometry. In the hybrid material, superparamagnetic Fe3O4 nanoparticles provide fast separation to simplify the analytical process and graphene oxide provides a large functional surface for the adsorption. The prepared magnetic nanocomposites were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and vibrating sample magnetometry. The experimental conditions were optimized systematically. Under the optimal conditions, the recoveries of these compounds were in the range of 98.3-125.2%, the relative standard deviations ranged between 6.8 and 15.5%, and the limits of detection were in the range of 0.01-0.15 ng/mL. The simple, quick, and affordable method was successfully used in the analysis of human urinary monohydroxy polycyclic aromatic hydrocarbons in two different cities. The results indicated that the monohydroxy polycyclic aromatic hydrocarbons level in human urine can provide useful information for environmental exposure to polycyclic aromatic hydrocarbons.

  18. Putting corannulene in its place. Reactivity studies comparing corannulene with other aromatic hydrocarbons.

    Science.gov (United States)

    George, Stephen R D; Frith, Thomas D H; Thomas, Donald S; Harper, Jason B

    2015-09-14

    A series of aromatic hydrocarbons were investigated so as to compare the reactivity of corannulene with planar aromatic hydrocarbons. Corannulene was found to be more reactive than benzene, naphthalene and triphenylene to Friedel-Crafts acylation whilst electrophilic aromatic bromination was also used to confirm that triphenylene was less reactive than corannulene and that pyrene, perylene and acenaphthene were more so. The stabilisation of a neighbouring carbocation by the various aromatic systems was investigated through consideration of the rates of methanolysis of a series of benzylic alcohols. The reactivity series was found to parallel that observed for the electrophilic aromatic substitutions and both series are supported by computational studies. As such, a reactivity scale was devised that showed that corannulene was less reactive than would be expected for an aromatic planar species of similar pi electron count. PMID:26220565

  19. CHARACTERIZING THE INFRARED SPECTRA OF SMALL, NEUTRAL, FULLY DEHYDROGENATED POLYCYCLIC AROMATIC HYDROCARBONS

    Energy Technology Data Exchange (ETDEWEB)

    Mackie, C. J.; Peeters, E.; Cami, J. [Department of Physics and Astronomy, University of Western Ontario, London, ON N6A 3K7 (Canada); Bauschlicher, C. W. Jr., E-mail: mackie@strw.leidenuniv.nl [NASA Ames Research Center, MS 245-6, Moffett Field, CA 94035 (United States)

    2015-02-01

    We present the results of a computational study to investigate the infrared spectroscopic properties of a large number of polycyclic aromatic hydrocarbon (PAH) molecules and their fully dehydrogenated counterparts. We constructed a database of fully optimized geometries for PAHs that is complete for eight or fewer fused benzene rings, thus containing 1550 PAHs and 805 fully dehydrogenated aromatics. A large fraction of the species in our database have clearly non-planar or curved geometries. For each species, we determined the frequencies and intensities of their normal modes using density functional theory calculations. Whereas most PAH spectra are fairly similar, the spectra of fully dehydrogenated aromatics are much more diverse. Nevertheless, these fully dehydrogenated species show characteristic emission features at 5.2 μm, 5.5 μm, and 10.6 μm; at longer wavelengths, there is a forest of emission features in the 16-30 μm range that appears as a structured continuum, but with a clear peak centered around 19 μm. We searched for these features in Spitzer-IRS spectra of various positions in the reflection nebula NGC 7023. We find a weak emission feature at 10.68 μm in all positions except that closest to the central star. We also find evidence for a weak 19 μm feature at all positions that is not likely due to C{sub 60}. We interpret these features as tentative evidence for the presence of a small population of fully dehydrogenated PAHs, and discuss our results in the framework of PAH photolysis and the formation of fullerenes.

  20. Quantitative determination of hydroxy polycylic aromatic hydrocarbons as a biomarker of exposure to carcinogenic polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Woudneh, Million B; Benskin, Jonathan P; Grace, Richard; Hamilton, M Coreen; Magee, Brian H; Hoeger, Glenn C; Forsberg, Norman D; Cosgrove, John R

    2016-07-01

    A high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS) method was developed for quantitative analysis of hydroxy polycyclic aromatic hydrocarbons (OH-PAHs). Four hydroxy metabolites of known and suspected carcinogenic PAHs (benzo[a]pyrene (B[a]P), benz[a]anthracene (B[a]A), and chrysene (CRY)) were selected as suitable biomarkers of PAH exposure and associated risks to human health. The analytical method included enzymatic deconjugation, liquid - liquid extraction, followed by derivatization with methyl-N-(trimethylsilyl) trifluoroacetamide and instrumental analysis. Photo-induced oxidation of target analytes - which has plagued previously published methods - was controlled by a combination of minimizing exposure to light, employing an antioxidant (2-mercaptoethanol) and utilizing a nitrogen atmosphere. Stability investigations also indicated that conjugated forms of the analytes are more stable than the non-conjugated forms. Accuracy and precision of the method were 77.4-101% (<4.9% RSD) in synthetic urine and 92.3-117% (<15% RSD) in human urine, respectively. Method detection limits, determined using eight replicates of low-level spiked human urine, ranged from 13 to 24pg/mL. The method was successfully applied for analysis of a pooled human urine sample and 78 mouse urine samples collected from mice fed with PAH-contaminated diets. In mouse urine, greater than 94% of each analyte was present in its conjugated form. PMID:27266337

  1. Polycyclic Aromatic Hydrocarbons as Plausible Prebiotic Membrane Components

    OpenAIRE

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

    2012-01-01

    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 p...

  2. NATO Advanced Research and CNRS Workshop on Polycyclic Aromatic Hydrocarbons and Astrophysics

    CERN Document Server

    d’Hendecourt, L; Boccara, N

    1987-01-01

    The near Infra-Red emission of the Interstellar Medium is a very puzzling subject. In the brightest regions, where spectroscopic observa­ tions are possible from the ground, several bands (3.3 - 3.4 - 6.2 - 7.7 - 8.6 - 11.3 ~m) have been observed since 1973. The absence of satisfying explanation was so obvious that they were called "Unidenti­ fied IR Emission Bands". The puzzle still increased when were known the first results of the general IR sky survey made by the satellite IRAS. On a large scale, the near IR emission of the Interstellar medium was expected to be very small but it was observed to be about one third of the total IR emission for our own galaxy ..• The situation has moved in 1984 when it was suggested that a class of stable organic molecules, the Polycyclic Aromatic Hydrocarbons (PAH's) could be at the origin of this near IR emission. Initially based on the required refractory character of particules that should be heated to high temperature without subliming, this hypothesis leads to a s...

  3. Aliphatic and aromatic hydrocarbons in Candiota coal samples: novel series of bicyclic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, A.C.M.L.; Loureiro, M.R.B.; Cardoso, J.N. [Universidade Federal do Rio de Janeiro, Rio de Janeiro (Brazil). Inst. de Quimica

    1999-07-01

    Gas chromatography - mass spectrometry was used to analyse aliphatic and aromatic fractions obtained from nine samples taken from two different seams of five boreholes in the Candiota coalfield (Lower Permian). The occurrence of certain tetracyclic diterpenoids among the aliphatic hydrocarbons, and the tricyclic diterpenoids simonellite and retene in the aromatic hydrocarbon concentrates, suggest an important input from conifers to the sedimentary biomass. This may explain the origin of a novel series of saturated and aromatic bicyclic compounds detected in the extracts which may be structurally related to the same precursor, possibly a conifer resin-derived tricyclic diterpenoid.

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

    International Nuclear Information System (INIS)

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

  5. Estimation of cytogenetic risk among coke oven workers exposed to polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Sureshkumar, Shanmugam; Balachandar, Vellingiri; Devi, Subramaniam Mohana; Arun, Meyyazhagan; Karthickkumar, Alagamuthu; Balamuralikrishnan, Balasubramanian; Sankar, Kathannan; Mustaqahamed, Shafi Ahammed Khan; Dharwadkar, Shanwaz N; Sasikala, Keshavarao; Cho, Ssang-Goo

    2013-01-01

    Polycyclic aromatic hydrocarbons (PAHs) result from the incomplete combustion of natural or synthetic organic materials. The working environment at a coke plant can negatively affect the employed workers who were exposed to coke oven emissions containing PAHs, which formed and released into the environment by the process of pyrolysis of coke. This study aims to analyze the relationship between the exposure of PAHs and the risk of genetic damages such as chromosomal alteration (CA), micronucleus (MN), and DNA damage (PCR-RFLP) in peripheral blood lymphocytes of 27 coke oven workers and equal number of control subjects. The exposed subjects and controls were divided into two groups based on their age (group Icoke oven workers under risk should be monitored for adverse effects of the any long-term exposure. PMID:24040626

  6. Sorption characteristics of polycyclic aromatic hydrocarbons in aluminum smelter residues.

    Science.gov (United States)

    Breedveld, Gijs D; Pelletier, Emilien; St Louis, Richard; Cornelissen, Gerard

    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 infinitesink 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 (-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.

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

    Science.gov (United States)

    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 (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. POLYCYCLIC AROMATIC HYDROCARBONS AND THE DIFFUSE INTERSTELLAR BANDS: A SURVEY

    International Nuclear Information System (INIS)

    We discuss the proposal of relating the origin of some of the diffuse interstellar absorption bands (DIBs) to neutral polycyclic aromatic hydrocarbons (PAHs) present in translucent interstellar clouds. An assessment of ionized PAHs will be examined in a future report. The spectra of several cold, isolated gas-phase PAHs have been measured in the laboratory under experimental conditions that mimic the interstellar conditions and are compared with an extensive set of astronomical spectra of reddened, early-type stars. This comparison provides-for the first time-accurate upper limits for the abundances of specific PAH molecules along specific lines of sight, something not attainable from IR observations alone. The comparison of these unique laboratory data with high-resolution, high signal-to-noise ratio spectra leads to two major findings: (1) a finding specific to the individual molecules that were probed in this study and, which leads to the clear and unambiguous conclusion that the abundance of these specific neutral PAHs must be very low in the individual translucent interstellar clouds that were probed in this survey (PAH features remain below the level of detection) and, (2) a general finding that neutral PAHs exhibit intrinsic band profiles that are similar to the profile of the narrow DIBs indicating that the carriers of the narrow DIBs must have close molecular structure and characteristics. This study is the first quantitative survey of neutral PAHs in the optical range and it opens the way for unambiguous quantitative searches of PAHs in a variety of interstellar and circumstellar environments.

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

    Directory of Open Access Journals (Sweden)

    Evin Danisman Bruschweiler

    2012-10-01

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

  10. PM₂.₅-bound polycyclic aromatic hydrocarbons in an area of Rio de Janeiro, Brazil impacted by emissions of light-duty vehicles fueled by ethanol-blended gasoline.

    Science.gov (United States)

    Oliveira, Rafael Lopes; Loyola, Josiane; Minho, Alan Silva; Quiterio, Simone Lorena; de Almeida Azevedo, Débora; Arbilla, Graciela

    2014-12-01

    The aim of this study was to characterize the PM2.5-bound polycyclic aromatic hydrocarbon (PAH) concentrations and their diagnostic ratios in an area impacted by light-duty vehicles fueled by neat ethanol and ethanol-blended gasoline. Samples were collected using a high-volume sampler, extracted, and analyzed for all 16 EPA-priority PAHs using gas chromatography/mass spectrometry (GC/MS) following the EPA 3550B Method. The most abundant PAHs were benzo[g,h,i]perylene, benzo[b]fluoranthene, benzo[a]pyrene and indeno[1,2,3-c,d]pyrene. The total mean concentration was 3.80 ± 2.88 ng m(-3), and the contribution of carcinogenic species was 58 ± 16 % of the total PAHs. The cumulative health hazard from the PAH mixture was determined, and the carcinogenic equivalents and mutagenic equivalents were 0.80 ± 0.82 and 1.17 ± 1.04 ng m(-3), respectively. Diagnostic ratios and normalized ratios were calculated for the individual samples.

  11. Hydrocarbons emissions from Cerro Prieto Geothermal Power Plant, Mexico

    Science.gov (United States)

    Navarro, Karina; Navarro-González, Rafael; de la Rosa, José; Peralta, Oscar; Castro, Telma; Imaz, Mireya

    2014-05-01

    One of the most important environmental issues related to the use of geothermal fluids to generate electricity is the emission of non-condensable gases to the atmosphere. Mexico has one of the largest geothermal plants in the world. The facility is located at Cerro Prieto, Baja California, roughly 30 km south of Mexicali and the international boundary between Mexico and United States. The Cerro Prieto power plant has 13 units grouped on four individual powerhouses. Gas samples from 9 units of the four powerhouses were collected during 4 campaigns conducted in May-July, 2010, February, 2012, December, 2012, and May, 2013. Gas samples from the stacks were collected in 1000 ml Pyrex round flasks with Teflon stopcocks, and analyzed by gas chromatography-mass spectrometry. Methane was the most abundant aliphatic hydrocarbon, with a concentration that ranged from less than 1% up to 3.5% of the total gas mixture. Normal alkanes represented the second most abundant species, and displayed a decreasing abundance with increasing carbon number in the homologous series. Isoalkanes were also present as isobutane and isopentane. Cycloalkanes occurring as cyclopentane and cyclohexane, were detected only at trace level. Unsaturated hydrocarbons (alkenes and alkynes) were not detected. Benzene was detected at levels ranging from less than 1% up to 3.4% of the total gas mixture. Other aromatic hydrocarbons detected were toluene, and xylenes, and were present at lower concentrations (

  12. Polycyclic aromatic hydrocarbons in atmospheric particles in the metropolitan area of Porto Alegre, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Dallarosa, J.B.; Monego, J.G.; Teixeira, E.C.; Stefens, J.L.; Wiegand, F. [Fundacao Estadual de Protecao Ambiental, Porto Alegre (Brazil)

    2005-03-01

    The aim of the present study is to identify and quantify the main sources of polycyclic aromatic hydrocarbons (PAHs) associated with aerosols (PM10) collected at three different sampling stations: 8 degrees Distrito, CEASA and Charqueadas. The samples were collected between November 2001 and November 2002, and the concentrations of 16 major PAHs were determined according to EPA. The filters containing particulate matter were extracted with dichloromethane in Soxhlet and the extracts were later analysed in a gaseous chromatograph coupled to a mass spectrometer (GS/MS). The average concentrations of PAHs ranged between 0.04 and 2.30ng m{sup -3}. The analysis of principal components was applied to the chemical and meteorological variables in order to facilitate the identification of sources of PAHs emission into the atmospheric particulate. The study identified the following sources of PAHs: vehicular emissions, such as diesel oil, petrol, alcohol, and kerosene; industrial emissions, like lubricating oils; emissions from hospital waste burning, and coal burning at power plants.

  13. POLYCYCLIC AROMATIC HYDROCARBON PROCESSING IN THE BLAST WAVE OF THE SUPERNOVA REMNANT N132D

    Energy Technology Data Exchange (ETDEWEB)

    Tappe, A. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS-72, Cambridge, MA 02138 (United States); Rho, J. [SOFIA Science Mission Operations/USRA, NASA Ames Research Center, MS 211-3, Moffett Field, CA 94035 (United States); Boersma, C. [NASA Ames Research Center, MS 245-6, Moffett Field, CA 94035 (United States); Micelotta, E. R., E-mail: atappe@cfa.harvard.edu [Department of Physics and Astronomy, Western University, 1151 Richmond Street, London, Ontario N6A 3K7 (Canada)

    2012-08-01

    We present Spitzer Infrared Spectrograph 14-36 {mu}m mapping observations of the supernova remnant N132D in the Large Magellanic Cloud. This study focuses on the processing of polycyclic aromatic hydrocarbons (PAHs) that we previously identified in the southern blast wave. The mid-infrared spectra show strong continuum emission from shock-heated dust and a unique, nearly featureless plateau in the 15-20 {mu}m region, which we attribute to PAH molecules. The typical PAH emission bands observed in the surrounding interstellar medium ahead of the blast wave disappear, which indicates shock processing of PAH molecules. The PAH plateau appears most strongly at the outer edge of the blast wave and coincides with diffuse X-ray emission that precedes the brightest X-ray and optical filaments. This suggests that PAH molecules in the surrounding medium are swept up and processed in the hot gas of the blast wave shock, where they survive the harsh conditions long enough to be detected. We also observe a broad emission feature at 20 {mu}m appearing with the PAH plateau. We speculate that this feature is either due to FeO dust grains or connected to the processing of PAHs in the supernova blast wave shock.

  14. POLYCYCLIC AROMATIC HYDROCARBON PROCESSING IN THE BLAST WAVE OF THE SUPERNOVA REMNANT N132D

    International Nuclear Information System (INIS)

    We present Spitzer Infrared Spectrograph 14-36 μm mapping observations of the supernova remnant N132D in the Large Magellanic Cloud. This study focuses on the processing of polycyclic aromatic hydrocarbons (PAHs) that we previously identified in the southern blast wave. The mid-infrared spectra show strong continuum emission from shock-heated dust and a unique, nearly featureless plateau in the 15-20 μm region, which we attribute to PAH molecules. The typical PAH emission bands observed in the surrounding interstellar medium ahead of the blast wave disappear, which indicates shock processing of PAH molecules. The PAH plateau appears most strongly at the outer edge of the blast wave and coincides with diffuse X-ray emission that precedes the brightest X-ray and optical filaments. This suggests that PAH molecules in the surrounding medium are swept up and processed in the hot gas of the blast wave shock, where they survive the harsh conditions long enough to be detected. We also observe a broad emission feature at 20 μm appearing with the PAH plateau. We speculate that this feature is either due to FeO dust grains or connected to the processing of PAHs in the supernova blast wave shock.

  15. Characteristics, toxicity, and source apportionment of polycylic aromatic hydrocarbons (PAHs) in road dust of Ulsan, Korea

    Energy Technology Data Exchange (ETDEWEB)

    Dong, T.T.T.; Lee, B.K. [University of Ulsan, Ulsan (Republic of Korea). Dept. of Civil & Environmental Engineering

    2009-03-15

    This study identified concentrations, molecular distributions, toxicities, and sources of polycyclic aromatic hydrocarbons (PAHs) in road dust from different areas of Ulsan, the largest industrial city in Korea. The total PAH concentrations in industrial areas were dependent on industrial emissions and vehicular exhaust, while those in urban areas were mainly dependent on traffic density, sampling site location, and accumulation of pollutants or road dust. The PAH concentration of each particle size group increased with decreasing particle size. This may be because of the higher surface area available for deposition or coating of PAHs in road dust with smaller particle sizes. The molecular distributions of PAHs among the sites in the petrochemical area and heavy traffic area were similar because of the similarities in their emission sources. The toxic equivalent concentrations (TEQs) of PAHs in the road dust ranged from 0.93 {mu}g/g to 16.74 {mu}g/g in industrial areas and from 4.37 {mu}g/g to 68.84 {mu}g/g in urban areas. The correlation coefficient of total PAH concentration and TEQ in urban areas was 0.98, which was much higher than that in industrial areas where it was 0.75. Principal component analysis showed that PAHs in road dust from Ulsan originate from four main sources: diesel vehicular emissions, oil combustion, gasoline vehicular emissions, and coal combustion.

  16. Characteristics, toxicity, and source apportionment of polycylic aromatic hydrocarbons (PAHs) in road dust of Ulsan, Korea.

    Science.gov (United States)

    Dong, Trang T T; Lee, Byeong-Kyu

    2009-03-01

    This study identified concentrations, molecular distributions, toxicities, and sources of polycylic aromatic hydrocarbons (PAHs) in road dust from different areas of Ulsan, the largest industrial city in Korea. The total PAH concentrations in industrial areas were dependent on industrial emissions and vehicular exhaust, while those in urban areas were mainly dependent on traffic density, sampling site location, and accumulation of pollutants or road dust. The PAH concentration of each particle size group increased with decreasing particle size. This may be because of the higher surface area available for deposition or coating of PAHs in road dust with smaller particle sizes. The molecular distributions of PAHs among the sites in the petrochemical area and heavy traffic area were similar because of the similarities in their emission sources. The toxic equivalent concentrations (TEQs) of PAHs in the road dust ranged from 0.93 microg/g to 16.74 microg/g in industrial areas and from 4.37 microg/g to 68.84 microg/g in urban areas. The correlation coefficient of total PAH concentration and TEQ in urban areas was 0.98, which was much higher than that in industrial areas where it was 0.75. Principal component analysis showed that PAHs in road dust from Ulsan originate from four main sources: diesel vehicular emissions, oil combustion, gasoline vehicular emissions, and coal combustion. PMID:19103459

  17. Rush-hour aromatic and chlorinated hydrocarbons in selected subway stations of Shanghai, China

    Institute of Scientific and Technical Information of China (English)

    Yanli Zhang; Chunlei Li; Xinming Wang; Hai Guo; Yanli Feng; Jianmin Chen

    2012-01-01

    Air samples were collected simultaneously at platform,mezzanine and outdoor in five typical stations of subway system in Shanghai,China using stainless steel canisters and analyzed by gas chromatography-mass selective detector (GC-MSD) after cryogenic preconcentration.Benzene,toluene,ethylbenzene and xylenes (BTEX) at the platforms and mezzanines inside the stations averaged (10.3± 2.1),(38.7 ± 9.0),(19.4 ± 10.1) and (30.0 ± 11.1) μg/m3,respectively; while trichloroethylene (TrCE),tetrachloroethylene (TeCE)and para-dichlorobenzene (pDCB),vinyl chloride and carbon tetrachloride were the most abundant chlorinated hydrocarbons inside the stations with average levels of (3.6 ± 1.3),(1.3 ± 0.5),(4.1 ± 1.1),(2.2 ± 1.1) and (1.2 ± 0.3) μg/m3,respectively.Mean levels of major aromatic and chlorinated hydrocarbons were higher indoor (platforms and mezzanines) than outdoor with average indoor/outdoor (I/O)ratios of 1.1-9.5,whereas no significant indoor/outdoor differences were found except for benzene and TrCE.The highly significant mutual correlations (p < 0.01) for BTEX between indoor and outdoor and their significant correlation (p < 0.05) with methyl tert-butyl ether (MTBE),a marker of traffic-related emission without other indoor and outdoor sources,indicated that BTEX were introduced into the subway stations from indoor/outdoor air exchange and traffic emission should be their dominant source.TrCE and pDCB were mainly from indoor emission and TeCE might have both indoor emission sources and contribution from outdoor air,especially in the mezzanines.

  18. Rush-hour aromatic and chlorinated hydrocarbons in selected subway stations of Shanghai, China.

    Science.gov (United States)

    Zhang, Yanli; Li, Chunlei; Wang, Xinming; Guo, Hai; Feng, Yanli; Chen, Jianmin

    2012-01-01

    Air samples were collected simultaneously at platform, mezzanine and outdoor in five typical stations of subway system in Shanghai, China using stainless steel canisters and analyzed by gas chromatography-mass selective detector (GC-MSD) after cryogenic preconcentration. Benzene, toluene, ethylbenzene and xylenes (BTEX) at the platforms and mezzanines inside the stations averaged (10.3 +/- 2.1), (38.7 +/- 9.0), (19.4 +/- 10.1) and (30.0 +/- 11.1) microg/m3, respectively; while trichloroethylene (TrCE), tetrachloroethylene (TeCE) and para-dichlorobenzene (pDCB), vinyl chloride and carbon tetrachloride were the most abundant chlorinated hydrocarbons inside the stations with average levels of (3.6 +/- 1.3), (1.3 +/- 0.5), (4.1 +/- 1.1), (2.2 +/- 1.1) and (1.2 +/- 0.3) microg/m3, respectively. Mean levels of major aromatic and chlorinated hydrocarbons were higher indoor (platforms and mezzanines) than outdoor with average indoor/outdoor (I/O) ratios of 1.1-9.5, whereas no significant indoor/outdoor differences were found except for benzene and TrCE. The highly significant mutual correlations (p tert-butyl ether (MTBE), a marker of traffic-related emission without other indoor and outdoor sources, indicated that BTEX were introduced into the subway stations from indoor/outdoor air exchange and traffic emission should be their dominant source. TrCE and pDCB were mainly from indoor emission and TeCE might have both indoor emission sources and contribution from outdoor air, especially in the mezzanines. PMID:22783624

  19. Emissions of non-methane hydrocarbons from cars in China

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    This study investigated the exhaust emission of non-methane hydrocarbons(NMHCs) from cars in China at the Beijing driving cycle on the chassis dynamometer.The emission factor average of NMHCs was 0.9 g/km,which was over twice that from the Australian car fleet and 2-4 times that of the American car emission in the 1990s-2000s.The emission profile of Beijing cars showed higher fractions of aromatics and C4?C7 HCs,and lower percentages of C2?C3 HCs,compared with those of the US car fleet.The average ratio of benzene/toluene for cars tested was 0.5,the average benzene/toluene/ethyl benzene/xylenes(BTEX) ratios were 1/2.2/0.1/1.8,which were consistent with those of the Tanyugou tunnel located in the suburb of Beijing.α-pinene and β-pinene were detected from the exhaust gas on dynamometer for the first time,and had likely similar exhaust emission characteristics with C2?C3 HCs and styrene,giving an evidence that air pinenes may be related to human activities.Isoprene was also detected directly.These observations suggest that the procedure regarding pinenes and isoprene as coming from biologic sources of VOCs in the atmosphere should be applied with great care,especially in the core of the big city like Beijing.The specific reactivity of NMHCs was higher than that of cars of US,and the specific reactivity of volatile aromatic compounds was higher than that of the US SPECIATE database.

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

    Science.gov (United States)

    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%.

  1. POLYCYCLIC AROMATIC HYDROCARBON CONTAMINATION LEVELS IN COLLECTED SAMPLES FROM VICINITY OF A HIGHWAY

    Directory of Open Access Journals (Sweden)

    S. V. Samimi ، R. Akbari Rad ، F. Ghanizadeh

    2009-01-01

    Full Text Available Tehran as the biggest city of Iran with a population of more than 10 millions has potentially high pollutant exposures of gas oil and gasoline combustion from vehicles that are commuting in the highways every day. The vehicle exhausts contain polycyclic aromatic hydrocarbons, which are produced by incomplete combustion and can be directly deposited in the environment. In the present study, the presence of polycyclic aromatic hydrocarbons contamination in the collected samples of a western highway in Tehran was investigated. The studied location was a busy highway in Tehran. High performance liquid chromatography equipped with florescence detector was used for determination of polycyclic aromatic hydrocarbons concentrations in the studied samples. Total concentration of the ten studied polycyclic aromatic hydrocarbons compounds ranged from 11107 to 24342 ng/g dry weight in the dust samples and increased from 164 to 2886 ng/g dry weight in the soil samples taken from 300 m and middle of the highway, respectively. Also the average of Σ PAHs was 1759 ng/L in the water samples of pools in parks near the highway. The obtained results indicated that polycyclic aromatic hydrocarbons contamination levels were very high in the vicinity of the highway.

  2. Bioremediation of Mixtures of High Molecular Weight Polycyclic Aromatic Hydrocarbons

    Science.gov (United States)

    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

  3. Aromatic hydrocarbons in the atmospheric environment. Part III: personal monitoring

    Science.gov (United States)

    Ilgen, E.; Levsen, K.; Angerer, J.; Schneider, P.; Heinrich, J.; Wichmann, H.-E.

    As part of a larger study, personal sampling of the aromatic hydrocarbons benzene, toluene, ethylbenzene and the isomeric xylenes (BTEX) was carried out by 55 nonsmoking volunteers for a period of 14 days. Thirty-nine persons lived in a rural area near Hannover (Germany) with hardly any traffic at all, while 16 persons lived in a high-traffic city street in Hannover. The personal exposure level of the persons in the rural area (some commuting to Hannover) was: 2.9, 24.8, 2.4 and 7.7 μg m -3 for benzene, toluene, ethylbenzene and the sum of xylenes, respectively, while the corresponding data for the high traffic city streets were 4.0, 22.2, 2.8 and 9.7 μg m -3 (geometric means). Four microenvironments have been monitored which contribute to the total exposure to BTEX, i.e. the home, the outdoor air, the workplace and the car cabin. The most important microenvironment for non-working persons is the private home. The concentration of most BTEX in the private home is almost equal to the personal exposure level, demonstrating that the indoor pollution in the home makes by far the highest contribution to the total exposure. For working people (mostly office workers), the workplace is the second most important microenvironment contributing to the total BTEX exposure. Taking all working persons into consideration (independent of the location of their private home) the personal exposure level is higher by a factor of 1.2-1.4 than that of the workplace (for toluene this factor is 2.2). As already found by others, very high BTEX concentrations may be found in car cabins, in particular, if the engine is gasoline-driven. In the cabin of 44 cars in the rural/urban area average benzene concentrations (geometric mean) of 12/14 μg m -3 and a maximum value of ˜550 μg m -3 were found. On average, the participating volunteers drove their car for 45 min day -1 (i.e. 3% of the day). Nevertheless, the car cabin constitutes about 10% of the total benzene exposure. Refueling of the

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-09-30

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

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

    International Nuclear Information System (INIS)

    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, H2O, CO2 (aerobic) or CH4 (anaerobic) and rate of biodegradation depends on pH, temperature, oxygen, microbial population, degree of acclimation, accessibility of nutrients, chemical structure of the compound, cellular transport properties, and chemical partitioning in growth medium. A number of bacterial species are known to degrade PAHs and most of them are isolated from contaminated soil or sediments. Pseudomonas aeruginosa, Pseudomons fluoresens, Mycobacterium spp., Haemophilus spp., Rhodococcus spp., Paenibacillus spp. are some of the commonly studied PAH-degrading bacteria. Lignolytic fungi too have the property of PAH degradation. Phanerochaete chrysosporium, Bjerkandera adusta, and Pleurotus ostreatus are the common PAH-degrading fungi. Enzymes involved in the degradation of PAHs are oxygenase, dehydrogenase and lignolytic enzymes. Fungal lignolytic enzymes are lignin peroxidase, laccase, and manganese peroxidase. They are extracellular and catalyze radical formation by oxidation to destabilize bonds in a molecule. The biodegradation of PAHs has been observed under both aerobic and anaerobic conditions and the rate can be

  6. Polycyclic aromatic hydrocarbons in the South American environment.

    Science.gov (United States)

    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

  7. Polycyclic aromatic hydrocarbons in the South American environment.

    Science.gov (United States)

    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

  8. A novel cloud-point extraction process for preconcentrating selected polycyclic aromatic hydrocarbons in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Bai, D.; Li, J.; Chen, S.B.; Chen, B.-H. [National University of Singapore (Singapore). Dept. of Chemical and Environmental Engineering

    2001-10-01

    Polycyclic aromatic hydrocarbons (PAHs) released in such processes as incomplete coal combustion and during the disposal of coal tar, are subject to strict emission controls in which the determination of PAHs has to be addressed. PAHs have low aqueous solubility which necessitates preconcentration prior to the analytical determination of PAHs. A novel but simple cloud-point extraction (CPE) process is developed to preconcentrate the trace of selected polycyclic aromatic hydrocarbons (PAHs) with the use of the readily biodegradable nonionic surfactant of secondary ethyoxylated alcohol Tergitol 15-S-7 as extractant. The concentrations of PAHs, mixtures of naphthalene and phenanthrene as well as pyrene in the spiked samples were determined with the new CPE process at ambient temperature (23{degree}C) followed by high performance liquid chromatography (HPLC) with fluorescence detection. More than 80% of phenanthrene and pyrene, respectively, and 96% of naphthalene initially present in the aqueous solutions with concentrations near or below their aqueous solubilities were recovered using this new CPE process. Importantly Tergitol 15-S-7 does not give any fluorometric signal to interfere with fluorescence detection of PAHs in the UV range. No special washing step is, thus, required to remove surfactant before HPLC analyses. Different experimental conditions were studied. The optimum conditions for the preconcentration and determination of these selected PAHs at ambient temperature have been established as the following: (1) 3 wt% surfactant; (2) addition of 0.5 M Na{sub 2}SO{sub 4}; (3) 10 min for equilibration time; and (4) 3000 rpm for centrifugal speed with duration of 10 min. 50 refs., 7 figs.

  9. Occurrence and transformation of tricyclic aromatic hydrocarbons in low rank coals

    Energy Technology Data Exchange (ETDEWEB)

    Hazai, I.; Alexander, G. (Hungarian Academy of Sciences, Budapest (Hungary). Research Laboratory for Inorganic Chemistry)

    1991-08-01

    Aromatic components of extracts obtained from four low rank coal samples were investigated by gas chromatography-mass spectrometry. A number of compounds were observed for the first time. The tricyclic aromatic hydrocarbons were investigated in detail. They show close similarities in structure to those reported to be formed in laboratory dehydrogenation experiments. The co-occurrence of molecules in the same samples containing additional unsaturation as well as the aromatic ring(s), offers strong support for the hypothesis of progressive aromatization of diterpenoids. A hypothetical diagenetic pathway is proposed to explain the generation of many of the compounds present. In the pathway the following reactions were considered: aromatization (i.e. dehydrogenation), elimination of substituents, methyl shift, isomerization and side chain shortening of fully aromatized species. 40 refs., 5 figs., 2 tabs.

  10. On the Aliphatic versus Aromatic Content of the Carriers of the "Unidentified" Infrared Emission Features

    CERN Document Server

    Yang, Xuejuan; Li, Aigen; Zhong, Jianxin

    2016-01-01

    Although it is generally accepted that the so-called "unidentified" infrared emission (UIE) features at 3.3, 6.2, 7.7, 8.6, and 11.3 micrometer are characteristic of the stretching and bending vibrations of aromatic hydrocarbon materials, the exact nature of their carriers remains unknown: whether they are free-flying, predominantly aromatic gas-phase molecules, or amorphous solids with a mixed aromatic/aliphatic composition are being debated. Recently, the 3.3 and 3.4 micrometer features which are commonly respectively attributed to aromatic and aliphatic C-H stretches have been used to place an upper limit of ~2\\% on the aliphatic fraction of the UIE carriers (i.e. the number of C atoms in aliphatic chains to that in aromatic rings). Here we further explore the aliphatic versus aromatic content of the UIE carriers by examining the ratio of the observed intensity of the 6.2 micrometer aromatic C-C feature (I6.2) to that of the 6.85 micrometer aliphatic C-H deformation feature (I6.85). To derive the intrinsic...

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

    Science.gov (United States)

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

    2010-01-01

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

  12. Factors affecting spatial variation of polycyclic aromatic hydrocarbons in surface soils in North China Plain.

    Science.gov (United States)

    Wang, Xilong; Zuo, Qian; Duan, Yonghong; Liu, Wenxin; Cao, Jun; Tao, Shu

    2012-10-01

    The spatial variation in concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) in surface soils in the North China Plain and the influential factors were examined in the present study. High concentrations of the sum of 16 PAHs (∑PAH(16) ) appeared in cities and their surrounding areas. Emissions and soil organic carbon (SOC) content significantly regulated spatial differentiation of PAH contamination in soils in the study area. Compared with emissions, concentrations of individual and total PAHs in soils were more closely controlled by the SOC content. Furthermore, concentrations of PAH species with lower molecular weight (e.g., two- or three-ring) in surface soils were more strongly correlated with the SOC content in comparison with those of higher molecular weight (e.g., five- or six-ring), mainly because of their higher saturated vapor pressure, thus higher mobility. The spatial variation of PAH species in soils in the North China Plain tended to be larger with increasing benzene ring numbers, and the difference in physicochemical properties of PAH species determined their distinct spatial distribution characteristics. The present study highlights the relative importance of emissions and SOC content in spatial variation of PAHs and the dependence of the spatial distribution characteristics of PAH species in surface soils on their physicochemical properties at a regional scale. Results of the present work are helpful for regional risk assessment of the contaminants tested. PMID:22847656

  13. Gas-Phase Polycyclic Aromatic Hydrocarbons in Absorption toward Protostellar Sources?

    Science.gov (United States)

    Bregman, Jesse D.; Temi, Pasquale

    2001-06-01

    One of the major criticisms of identifying the infrared emission bands with polycyclic aromatic hydrocarbon (PAH) molecules has been the lack of a match between laboratory spectra of individual PAHs and the emission features. Part of the difficulty arises from the complexity of modeling the emission mechanism with an a priori unknown mixture of ionized and neutral PAHs. A direct comparison between laboratory spectra of PAHs and astronomical sources is possible for absorption spectra. However, because of poor atmospheric transmission, ground-based spectra of the PAH absorption band in the C-H stretch region are too noisy to make a detailed comparison with laboratory spectra. In this paper we show that ISO Short Wavelength Spectrometer spectra of a few protostars that show a 3.25 μm absorption band can be well matched by laboratory absorption spectra of a mixture of isolated PAHs. Based on observations with ISO, an ESA project with instruments funded by ESA member states (especially the PI countries: France, Germany, the Netherlands, and the United Kingdom), with the participation of ISAS and NASA.

  14. Source apportionment of polycyclic aromatic hydrocarbons in the Dahuofang Reservoir, Northeast China.

    Science.gov (United States)

    Lin, Tian; Qin, Yanwen; Zheng, Binghui; Li, Yuanyuan; Chen, Ying; Guo, Zhigang

    2013-01-01

    Polycyclic aromatic hydrocarbons (PAHs) in 24 surface sediments from the Dahuofang Reservoir (DHF), the largest man-made lake in Northeast China, were measured. The results showed that the concentrations of 16 US EPA priority PAHs in the sediments ranged from 323 to 912 ng/g dry weight with a mean concentration of 592 ± 139 ng/g. The PAH source contributions were estimated based on positive matrix factorization model. The coal combustion contributed to 31 % of the measured PAHs, followed by residential emissions (22%), biomass burning (21%), and traffic-related emissions (10%). Pyrogenic sources contributed ~84% of anthropogenic PAHs to the sediments, indicating that energy consumption release was a predominant contribution of PAH pollution in DHF. Compared with the results from the urban atmospheric PAHs in the region, there was a low contribution from traffic-related emissions in the sediments possibly due to the low mobility of the traffic-related derived 5+6-ring PAHs and their rapid deposition close to the urban area. PMID:22454050

  15. Dust and Polycyclic Aromatic Hydrocarbon in the Pre-Transitional Disk around HD 169142

    CERN Document Server

    Seok, Ji Yeon

    2015-01-01

    The pre-transitional disk around the Herbig Ae star HD 169142 shows a complex structure of possible ongoing planet formation in dust thermal emission from the near infrared (IR) to millimeter wavelength range. Also, a distinct set of broad emission features at 3.3, 6.2, 7.7, 8.6, 11.3, and 12.7 $\\mu$m, commonly attributed to polycyclic aromatic hydrocarbons (PAHs), are detected prominently in the HD 169142 disk. We model the spectral energy distribution (SED) as well as the PAH emission features of the HD 169142 disk simultaneously with porous dust and astronomical-PAHs taking into account the spatially resolved disk structure. Our porous dust model consisting of three distinct components that are primarily concentrated in the inner ring, middle ring, and outer disk, respectively, provides an excellent fit to the entire SED, and the PAH model closely reproduces the observed PAH features. The accretion of ice mantles onto porous dust aggregates occurs between ~16 AU and 60 AU, which overlaps with the spatial e...

  16. Spatiotemporal patterns and source implications of aromatic hydrocarbons at six rural sites across China's developed coastal regions

    Science.gov (United States)

    Zhang, Zhou; Zhang, Yanli; Wang, Xinming; Lü, Sujun; Huang, Zhonghui; Huang, Xinyu; Yang, Weiqiang; Wang, Yuesi; Zhang, Qiang

    2016-06-01

    Aromatic hydrocarbons are important anthropogenic precursors of tropospheric ozone and secondary organic aerosols. Here we measured ambient aromatic hydrocarbons from March 2012 to February 2014 at six rural sites in China's developed coastal regions. On average, benzene (B) comprised > 50% of total benzene (B), toluene (T), ethylbenzene (E), and xylenes (X) (BTEX) at sites in the Northeast China Plain (NECP) or in the North China Plain (NCP), whereas T, E, and X accounted for > 77% of total BTEX at sites in the Yangtze River Delta (YRD) and the Pearl River Delta in the south. BTEX at the northern sites was significantly correlated (p tetrachloroethylene, an industrial emission tracer. The B/CO emission ratios from measurement agreed within a factor of 2 with that of a previous widely used emission inventory of China, but the T/CO ratio at the NECP site and the o-X/CO ratio at the NCP site were 29% and 38% of that in the inventory, respectively; the E/CO and X/CO ratios at the YRD site were 3.2-3.5 fold that in the emission inventory.

  17. Evaluation of ginkgo as a biomonitor of airborne polycyclic aromatic hydrocarbons

    Science.gov (United States)

    Murakami, Michio; Abe, Maho; Kakumoto, Yoriko; Kawano, Hiromi; Fukasawa, Hiroko; Saha, Mahua; Takada, Hideshige

    2012-07-01

    The utility of ginkgo leaves as biomonitors of airborne polycyclic aromatic hydrocarbons (PAHs) was evaluated. We investigated PAH concentrations among tree species, the effect of variations in leaf position in a tree, tissue distributions, correlations between ginkgo leaves and air, and seasonal variations. Among the five species examined (Ginkgo biloba L., Zelkova serrata Makino, Liriodendron tulipifera L., Prunus yedoensis Matsum, and Magnolia kobus DC.), ginkgo accumulated the greatest amount of PAHs from roadside air. Most PAHs (˜80%) were accumulated in the wax fraction, and most of the remainder (17%) penetrated the inner tissues of the leaves. PAH concentrations in ginkgo leaves decreased with increasing height and distance from the road, reflecting the derivation of PAHs from vehicle emissions. Seasonal time-series sampling showed that PAH concentrations in ginkgo leaves increased with time, attributable to the effects of temperature and accumulation through long-term exposure. Concentrations in ginkgo leaves collected from various roads showed a strong and significant correlation with those in air collected by a high-volume air sampler (r2 = 0.68, P Ginkgo leaf data clearly showed a dramatic decrease in the ratio of low-molecular-weight (LMW) PAHs to high-molecular-weight PAHs from 2001 or 2002 to 2006, indicating that on-road diesel emission regulations effectively reduced LMW PAH concentrations in air.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-07-01

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

  19. Anthropogenic input of polycyclic aromatic hydrocarbons into five lakes in Western China

    Energy Technology Data Exchange (ETDEWEB)

    Guo Jianyang [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China); Wu Fengchang, E-mail: wufengchang@vip.skleg.c [State Environmental Protection Key Laboratory for Lake Pollution Control, Research Center of Lake Eco-Environment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China); Luo Xiaojun [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Liang Zhang [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China); State Environmental Protection Key Laboratory for Lake Pollution Control, Research Center of Lake Eco-Environment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Liao Haiqing [State Environmental Protection Key Laboratory for Lake Pollution Control, Research Center of Lake Eco-Environment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Zhang Runyu; Li Wen [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China); Zhao Xiaoli [State Environmental Protection Key Laboratory for Lake Pollution Control, Research Center of Lake Eco-Environment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Chen Shejun; Mai Bixian [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China)

    2010-06-15

    The temporal distribution of polycyclic aromatic hydrocarbons (PAHs) was examined in dated sediments from five lakes in Western China. The surficial concentrations of seven carcinogenic PAHs (BaA, Chyr, BbF, BkF, BaP, DBA and INP, hereafter denoted as PAH{sub 7}) were highly site-specific. The SIGMAPAH{sub 7} concentrations generally increased from the deep layers to surface sediments. The temporal trends of SIGMAPAH{sub 7} concentrations were clearly different from those reported in developed countries. From 1950s to 1980s, which PAHs started to decrease in developed countries, is the right period that PAHs started to increase rapidly in Western China. The fluxes and mass inventories suggest that the PAH{sub 7} input over the past three decades was much more rapidly than it was before the 1980s. Source identification indicates that the PAHs were primarily from biomass burning and domestic coal combustion, and increasing vehicular and/or industrial coal combustion emission was also found. - The present manuscript provides critical information for comprehensive understanding of the temporal trends of PAHs in lake sediments from Western China and the global PAHs emission.

  20. Impact of maritime traffic on polycyclic aromatic hydrocarbons, metals and particulate matter in Venice air.

    Science.gov (United States)

    Gregoris, Elena; Barbaro, Elena; Morabito, Elisa; Toscano, Giuseppa; Donateo, Antonio; Cesari, Daniela; Contini, Daniele; Gambaro, Andrea

    2016-04-01

    Harbours are important hubs for economic growth in both tourism and commercial activities. They are also an environmental burden being a source of atmospheric pollution often localized near cities and industrial complexes. The aim of this study is to quantify the relative contribution of maritime traffic and harbour activities to atmospheric pollutant concentration in the Venice lagoon. The impact of ship traffic was quantified on various pollutants that are not directly included in the current European legislation for shipping emission reduction: (i) gaseous and particulate PAHs; (ii) metals in PM10; and (iii) PM10 and PM2.5. All contributions were correlated with the tonnage of ships during the sampling periods and results were used to evaluate the impact of the European Directive 2005/33/EC on air quality in Venice comparing measurements taken before and after the application of the Directive (year 2010). The outcomes suggest that legislation on ship traffic, which focused on the issue of the emissions of sulphur oxides, could be an efficient method also to reduce the impact of shipping on primary particulate matter concentration; on the other hand, we did not observe a significant reduction in the contribution of ship traffic and harbour activities to particulate PAHs and metals. Graphical abstract Impact of maritime traffic on polycyclic aromatic hydrocarbons, metals and particulate matter and evaluation of the effect of an European Directive on air quality in Venice. PMID:26681325

  1. Elements and polycyclic aromatic hydrocarbons in exhaust particles emitted by light-duty vehicles.

    Science.gov (United States)

    Alves, Célia A; Barbosa, Cátia; Rocha, Sónia; Calvo, Ana; Nunes, Teresa; Cerqueira, Mário; Pio, Casimiro; Karanasiou, Angeliki; Querol, Xavier

    2015-08-01

    The main purpose of this work was to evaluate the chemical composition of particulate matter (PM) emitted by eight different light-duty vehicles. Exhaust samples from petrol and diesel cars (Euro 3 to Euro 5) were collected in a chassis dynamometer facility. To simulate the real-world driving conditions, three ARTEMIS cycles were followed: road, to simulate a fluid traffic flow and urban with hot and cold starts, to simulate driving conditions in cities. Samples were analysed for the water-soluble ions, for the elemental composition and for polycyclic aromatic hydrocarbons (PAHs), respectively, by ion chromatography, inductively coupled plasma atomic emission spectroscopy (ICP-AES), inductively coupled plasma mass spectrometry (ICP-MS) and gas chromatography-mass spectrometry (GC-MS). Nitrate and phosphate were the major water-soluble ions in the exhaust particles emitted from diesel and petrol vehicles, respectively. The amount of material emitted is affected by the vehicle age. For vehicles ≥Euro 4, most elements were below the detection limits. Sodium, with emission factors in the ranges 23.5-62.4 and 78.2-227μg km(-1), for petrol and diesel Euro 3 vehicles, respectively, was the major element. The emission factors of metallic elements indicated that diesel vehicles release three to five times more than petrol automobiles. Element emissions under urban cycles are higher than those found for on-road driving, being three or four times higher, for petrol vehicles, and two or three times, for diesel vehicles. The difference between cycles is mainly due to the high emissions for the urban cycle with hot start-up. As registered for elements, most of the PAH emissions for vehicles ≥Euro 4 were also below the detection limits. Regardless of the vehicle models or driving cycles, the two- to four-ring PAHs were always dominant. Naphthalene, with emission factors up to 925 μg km(-1), was always the most abundant PAH. The relative cancer risk associated with

  2. Probing the role of polycyclic aromatic hydrocarbons in the photoelectric heating within photodissociation regions

    NARCIS (Netherlands)

    Okada, Y.; Pilleri, P.; Berne, O.; Ossenkopf, V.; Fuente, A.; Goicoechea, J. R.; Joblin, C.; Kramer, C.; Roellig, M.; Teyssier, D.; van der Tak, F. F. S.

    2013-01-01

    Aims. We observationally investigate the relation between the photoelectric heating efficiency in photodissociation regions (PDRs) and the charge of polycyclic aromatic hydrocarbons (PAHs), which are considered to play a key role in photoelectric heating. Methods. Using PACS onboard Herschel, we obs

  3. 多环芳烃的加氢裂化%Hydrocracking of polycyclic aromatic hydrocarbons

    Institute of Scientific and Technical Information of China (English)

    张全信; 刘希尧

    2001-01-01

    This paper reviews the progress on the catalysts, reaction network and reaction mechanism for hydrocracking of polycyclic aromatic hydrocarbons in recent years.%本文综述了近年来多环芳烃加氢裂化反应催化剂、反应网络及反应机理等方面的研究进展。

  4. Weathering and toxicity of marine sediments contaminated with oils and polycyclic aromatic hydrocarbons

    NARCIS (Netherlands)

    Jonker, M.T.O.; Sinke, A.; Brils, J.M.; Murk, A.J.; Koelmans, A.A.

    2006-01-01

    Many sediments are contaminated with mixtures of oil residues and polycyclic aromatic hydrocarbons (PAHs), but little is known about the toxicity of such mixtures to sediment-dwelling organisms and the change in toxicity on weathering. In the present study, we investigated the effects of a seminatur

  5. Longitudinal study of excretion of metabolites of polycyclic aromatic hydrocarbons in urine from two psoriatic patients

    DEFF Research Database (Denmark)

    Hansen, Åse Marie; Poulsen, O M; Menné, T

    1993-01-01

    Coal tar, which is widely used in the treatment of patients with atopic dermatitis, chronic eczema, and psoriasis, contains a large amount of polycyclic aromatic hydrocarbons (PAH). Some of the PAH compounds are known either to be carcinogenic or to potentiate the effects of other carcinogenic...

  6. Gas-phase infrared spectra of cationized nitrogen-substituted polycyclic aromatic hydrocarbons

    NARCIS (Netherlands)

    Galué, Alvaro; Pirali, O.; Oomens, J.

    2010-01-01

    Gas-phase infrared spectra of several ionized nitrogen substituted polycyclic aromatic hydrocarbons (PANHs) have been recorded in the 600-1600 cm(-1) region via IR multiple-photon dissociation (IRMPD) spectroscopy. The UV photoionized PANH ions are trapped and isolated in a quadrupole ion trap where

  7. Gas-phase infrared spectra of cationized nitrogen-substituted polycyclic aromatic hydrocarbons

    NARCIS (Netherlands)

    H.A. Galué; O. Pirali; J. Oomens

    2010-01-01

    Gas-phase infrared spectra of several ionized nitrogen substituted polycyclic aromatic hydrocarbons (PANHs) have been recorded in the 600-1600 cm-1 region via IR multiple-photon dissociation (IRMPD) spectroscopy. The UV photoionized PANH ions are trapped and isolated in a quadrupole ion trap where t

  8. Availabiltiy and leaching of polycyclic aromatic hydrocarbons: Controlling processes and comparison of testing methods

    NARCIS (Netherlands)

    Roskam, G.; Comans, R.N.J.

    2009-01-01

    We have studied the availability and leaching of polycyclic aromatic hydrocarbons (PAHs) from two contaminated materials, a tar-containing asphalt granulate (¿16 US-EPA PAHs 3412 mg/kg) and gasworks soil (¿PAHs 900 mg/kg), by comparing results from three typical types of leaching tests: a column, se

  9. Extraction of polycyclic aromatic hydrocarbons from soot and sediment : solvent selection and implications for sorption mechanism

    NARCIS (Netherlands)

    Jonker, M.T.O.; Koelmans, A.A.

    2002-01-01

    Soot contains high levels of toxic compounds such as polycyclic aromatic hydrocarbons (PAHs). Extraction of PAHs from soot for quantitative analysis is difficult because the compounds are extremely tightly bound to the sorbent matrix. This study was designed to investigate the effect of solvent type

  10. Development of analytical methods for polycyclic aromatic hydrocarbons (PAHs) in airborne particulates:A review

    Institute of Scientific and Technical Information of China (English)

    LIU Li-bin; LIU Yan; LIN Jin-ming; TANG Ning; HAYAKAWA Kazuichi; MAEDA Tsuneaki

    2007-01-01

    In the present work,the different sample collection, pretreatment and analytical methods for polycyclic aromatic hydrocarbons (PAHs) in airborne particulates is systematacially reviewed, and the applications of these pretreatment and analytical methods for PAHs are compared in detail. Some comments on the future expectation are also presented.

  11. Polycyclic aromatic hydrocarbons and dust in regions of massive star formation

    NARCIS (Netherlands)

    Peeters, Els

    2002-01-01

    Polycyclic Aromatic Hydrocarbons (PAHs) are known on earth as a large family of tarry materials naturally present in for example coal and crude oil. In addition, they are also formed in the combustion of all sorts of carbonaceous fuels and hence are found in auto exhaust, cigarette smoke, candle soo

  12. Gas phase adiabatic electron affinities of cyclopenta-fused polycyclic aromatic hydrocarbons

    NARCIS (Netherlands)

    Todorov, P.D.; Koper, C.; van Lenthe, J.H.; Jenneskens, L.W.

    2008-01-01

    The B3LYP/DZP++ adiabatic electron affinity (AEA) of nine (non)-alternant polycyclic aromatic hydrocarbons are reported and discussed. Calculations became feasible for molecules this size by projecting out the near-linearly dependent part of the one-electron basis. Non-alternant PAH consisting of an

  13. Polycyclic aromatic hydrocarbon ionization as a tracer of gas flows through protoplanetary disk gaps

    NARCIS (Netherlands)

    K.M. Maaskant; M. Min; L.B.F.M. Waters; A.G.G.M. Tielens

    2014-01-01

    Context. Planet-forming disks of gas and dust around young stars contain polycyclic aromatic hydrocarbons (PAHs). Aims. We aim to characterize how the charge state of PAHs can be used as a probe of flows of gas through protoplanetary gaps. In this context, our goal is to understand the PAH spectra o

  14. Effect of three polycyclic aromatic hydrocarbons on nodulation of Rhizobium tropici CIAT 899 on Phaseolus vulgaris

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Paredes, Y.; Ferrera-Cerrato, R.; Alarcon, A.

    2009-07-01

    Polycyclic aromatic hydrocarbons (PAH) are ubiquitous organic pollutants that are considered toxic and carcinogenic compounds to living organisms. There us scarce information about the effect of PAH on symbiotic systems such as Azolla-Anabaena, arbuscular mycorrhizal fungi-plants, or legume-rhizobia. (Author)

  15. Supercooled liquid vapour pressures and related thermodynamic properties of polycyclic aromatic hydrocarbons determined by gas chromatography

    NARCIS (Netherlands)

    J.J.H. Haftka; J.R. Parsons; H.A.J. Govers

    2006-01-01

    A gas chromatographic method using Kovats retention indices has been applied to determine the liquid vapour pressure (P-i), enthalpy of vaporization (Delta H-i) and difference in heat capacity between gas and liquid phase (Delta C-i) for a group of polycyclic aromatic hydrocarbons (PAHs). This group

  16. COMPARATIVE STUDIES OF THE EFFECT OF POLYCYCLIC AROMATIC HYDROCARBON GEOMETRY ON THE HYDROLYSIS OF DIOL EPOXIDES

    Science.gov (United States)

    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...

  17. [Retrieval of monocyclic aromatic hydrocarbons with differential optical absorption spectroscopy].

    Science.gov (United States)

    Xie, Pin-Hua; Fu, Qiang; Liu, Jian-Guo; Liu, Wen-Qing; Qin, Min; Li, Ang; Liu, Shi-Sheng; Wei, Qing-Nong

    2006-09-01

    Differential optical absorption spectroscopy (DOAS) technique has been used to measure trace gases in the atmosphere by their strongly structured absorption of radiation in the UV and visible spectral range, e. g. SO2, NO2, O3 etc. However, unlike the absorption spectra of SO2 and NO2, the analysis of aromatic compounds is difficult and strongly suffers from the cross interference of other absorbers (Herzberg bands of oxygen, ozone and sulfur dioxide), especially with relatively low concentrations of aromatic compounds in the atmosphere. In the present paper, the DOAS evaluation of aromatic compounds was performed by nonlinear least square fit with two interpolated oxygen optical density spectra at different path lengths and reference spectra of ozone at different temperature and SO2 cross section to correct the interference from absorbers of O2, O3 and SO2. The measurement of toluene, benzene, (m, p, o) xylene and phenol with a DOAS system showed that DOAS method is suitable for monocyclic aromatic compounds monitoring in the atmosphere. PMID:17112022

  18. Differences of diurnal variations of some aliphatic and polycyclic aromatic hydrocarbons concentrations in aerosol of the urban area of Madrid

    International Nuclear Information System (INIS)

    A study on daily concentration changes of polycyclic aromatic and aliphatic hydrocarbons (PAH's and AH's), was carried out in aerosols sampled in the Ciudad Universitaria of Madrid. Samples were taken at morning and night during February and June, for short sampling times, on glass fiber filters in Hi-Vol samplers, and then extracted ultrasonically with cyclohexane. Analysis were performed by HRGC with fused-silica capillary columns. The variable traffic rate, and the strong influence during winter periods of domestic heating are characteristic of this place. The aim of this work was to evaluate diurnal and seasonal variations of selected AH and PAH in the urban area of Madrid, by using descriptive parameters, such as total concentrations of AH and PAH, characteristic profiles and predominance carbon index. From these results, it has been tried to identify emission sources of the studied hydrocarbons. (Author). 10 refs

  19. Biodegradation of Various Aromatic Compounds by Enriched Bacterial Cultures: Part A-Monocyclic and Polycyclic Aromatic Hydrocarbons.

    Science.gov (United States)

    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.

  20. Non-covalent Interactions of Graphene with Polycyclic Aromatic Hydrocarbons

    NARCIS (Netherlands)

    Zygouri, Panagiota; Potsi, Georgia; Mouzourakis, Eleftherios; Spyrou, Konstantinos; Gournis, Dimitrios; Rudolf, Petra

    2015-01-01

    In this mini review we discuss the interactions of polyaromatic hydrocarbons (PAHs) with graphene and the experimental approaches developed so far to create novel graphene/PAH hybrids and composite systems. The utilization of these systems in electrical, biomedical and polymer-reinforcement applicat

  1. Adsorption of polar aromatic hydrocarbons on synthetic calcite

    DEFF Research Database (Denmark)

    Madsen, Lene; Grahl-Madsen, Laila; Grøn, Christian;

    1996-01-01

    The wettability of hydrocarbon reservoirs depends on how and to what extent the organic compounds are adsorbed onto the surfaces of calcite, quartz and clay. A model system of synthetic call cite, cyclohexane and the three probe molecules: benzoic acid, benzyl alcohol and benzylamine, have been...

  2. Degradation of benzene and other aromatic hydrocarbons by anaerobic bacteria

    NARCIS (Netherlands)

    Weelink, S.A.B.

    2008-01-01

    Accidental spills, industrial discharges and gasoline leakage from underground storage tanks have resulted in serious pollution of the environment with monoaromatic hydrocarbons, such as benzene, toluene, ethylbenzene and xylene (so-called BTEX). High concentrations of BTEX have been detected in soi

  3. Polycyclic aromatic hydrocarbons in atmospheric depositions around the Venice Lagoon

    OpenAIRE

    Rossini, Paolo; Matteucci, Gabriele; Raccanelli, Stefano; Favotto, Maurizio; Guerzoni, Stefano; Gattolin, Massimo

    2007-01-01

    Studies have revealed the potential risks to which human health and ecosystems are exposed in the Venice Lagoon, due to the atmospheric deposition of persistent pollutants such as trace metals and organic compounds. A total of 77 atmospheric bulk deposition samples were collected monthly from April 2002 to December 2004, from three sites located in the cities of Mestre and Venice, and inside the industrial area of Porto Marghera. Samples were analyzed by HRGC/HRMS for polycyclic aromatic hydr...

  4. Aromatic Hydrocarbons: Degrading Bacteria in the Desert Soil of Kuwait

    International Nuclear Information System (INIS)

    Soil samples of different levels of oil pollutants were collected from Kuwait's Burgan Oil Field, near an oil lake. The samples represented, highly polluted (8.0% w/w), moderately polluted (2.1%-3.4%) and slightly polluted (2.1%-3.4%) and slightly polluted (0.5- 0.8%). The aromatic fractions of the collected samples were in the range of (0.21-2.57g/100g) soil. (GC) analysis of the aromatic fractions of the resolution of the different individual (PAHs) revealed the presence of (16) different (PAHs) resolved from the aromatic fraction of the highly polluted sample (S3). (15), (14) and (13) individual (PAHs) were identified soil samples (S5), (S2) and (S1, S4, S6) respectively. The most frequent (PAH) was indeno (1, 2, 3-c, d) pyrene (22.5%-45.11%) followed chrysene (13.6%-19.48%). Eight carcinogenic (PAHs) were resolved from the aromatic fractions of the polluted samples. Total carcinogenic (PAHs) recorded in this study were in this study were in the range of (11.53) (forS4) - (510.98) (for S3) ppm. The counts of (CFU) of aromatic degraders (AD) were in the range of (3x10) - (110x 10) (CFU/g) soil (with a percent of (2.2%-69.6%)). The results show that, higher counts of (AD) were recorded from a highly polluted sample (S3), followed by the moderately polluted samples; total of (51) bacteria, that gave presumptive positive biodegradation activities, were isolated and identified (45.1%) of them were isolated and identified. (45.1%) of them were isolated from the highly polluted sample (S3). Total of (13) different species were identified of which Micrococcus luteus was more frequent (23.5) followed by Bacillus licheniformis (19.6%) and Bacillus subtilis (11.8%). The three Pseudomonas species collectively were presented by (11.8%). Five different species proved to be of good activities, they are: Bacillus brevis, Bacillus lichenoformis, Pseudomonas aeruginosa, Pseudomonas stutzeri and Pseudomonas flourescens. The ability of five species and their mixture was

  5. Polycyclic aromatic hydrocarbons from rural household biomass burning in a typical Chinese village

    Institute of Scientific and Technical Information of China (English)

    WANG HaiLin; ZHUANG YaHui; HAO ZhengPing; CAO MeiQiu; ZHONG JinXian; WANG XiaoKe; NGUYEN Thi Kim Oanh

    2008-01-01

    Biomass energy sources are still popular in the rural areas of developing countries for cooking and space heating. Since the incomplete combustion of agricultural residues in home-made ranges might lead to both outdoor and indoor air pollution and cause potential health threat to the rural population,we monitored the ambient levels of 16 US EPA priority polycyclic aromatic hydrocarbons (PAHs) at a typical rural site. Ambient particulate PAH samples (PM2.5 and PM10) were taken during both cooking and non-cooking periods. Source emission monitoring was also conducted for both improved and traditional cooking stoves used in the area. Ambient PAHs had a significant increase during the cooking periods and varied from 72.1 to 554.4 ng/m3. The highest total PAH levels were found during the supper cooking time,in which five- and six-ring species accounted for a large proportion. The observed PAH levels during cooking periods at this rural site were even higher than those in urban areas. A good correlation was found between the benzo[a]pyrene level and the total PAH concentration (r=0.98),making benzo[a]pyrene a potential molecular marker for PAH pollution in the rural areas,where biomass burning is typical. The profiles of the particulate PAHs in both ambient air and source emissions showed a high proportion of high molecular-mass PAHs. In addition,emission factors of 16 PAHs from an improved household stove were found to be significantly lower than those from traditional stoves used in China and in other Asian countries.

  6. Polycyclic aromatic hydrocarbons from rural household biomass burning in a typical Chinese village

    Institute of Scientific and Technical Information of China (English)

    NGUYEN; Thi; Kim; Oanh

    2008-01-01

    Biomass energy sources are still popular in the rural areas of developing countries for cooking and space heating. Since the incomplete combustion of agricultural residues in home-made ranges might lead to both outdoor and indoor air pollution and cause potential health threat to the rural population, we monitored the ambient levels of 16 US EPA priority polycyclic aromatic hydrocarbons (PAHs) at a typical rural site. Ambient particulate PAH samples (PM2.5 and PM10) were taken during both cooking and non-cooking periods. Source emission monitoring was also conducted for both improved and tra- ditional cooking stoves used in the area. Ambient PAHs had a significant increase during the cooking periods and varied from 72.1 to 554.4 ng/m3. The highest total PAH levels were found during the supper cooking time, in which five- and six-ring species accounted for a large proportion. The observed PAH levels during cooking periods at this rural site were even higher than those in urban areas. A good correlation was found between the benzo[a]pyrene level and the total PAH concentration (r=0.98), making benzo[a]pyrene a potential molecular marker for PAH pollution in the rural areas, where bio- mass burning is typical. The profiles of the particulate PAHs in both ambient air and source emissions showed a high proportion of high molecular-mass PAHs. In addition, emission factors of 16 PAHs from an improved household stove were found to be significantly lower than those from traditional stoves used in China and in other Asian countries.

  7. Level, potential sources of polycyclic aromatic hydrocarbons (PAHs) in particulate matter (PM10) in Naples

    Science.gov (United States)

    Di Vaio, Paola; Cocozziello, Beatrice; Corvino, Angela; Fiorino, Ferdinando; Frecentese, Francesco; Magli, Elisa; Onorati, Giuseppe; Saccone, Irene; Santagada, Vincenzo; Settimo, Gaetano; Severino, Beatrice; Perissutti, Elisa

    2016-03-01

    In Naples, particulate matter PM10 associated with polycyclic aromatic hydrocarbons (PAHs) in ambient air were determined in urban background (NA01) and urban traffic (NA02) sites. The principal objective of the study was to determine the concentration and distribution of PAHs in PM10 for identification of their possible sources (through diagnostic ratio - DR and principal component analysis - PCA) and an estimation of the human health risk (from exposure to airborne TEQ). Airborne PM10 samples were collected on quartz filters using a Low Volume Sampler (LVS) for 24 h with seasonal samples (autumn, winter, spring and summer) of about 15 days each between October 2012 and July 2013. The PM10 mass was gravimetrically determined. The PM10 levels, in all seasons, were significantly higher (P agents, (i.e Benzo[a]Pyrene, Indeno[1,2,3-cd]Pyrene, Benzo[b]Fluoranthene, Benzo[k]Fluoranthene and Benzo[g,h,i]Perylene), had a large contribution (∼50-55%) of total PAHs concentration in PM10 in two sites and in each of the campaigns. Diagnostic ratio analysis and PCA suggested a substantial contributions from traffic emission with minimal influence from coal combustion and natural gas emissions. In particular diesel vehicular emissions were the major source of PAHs at the studied sites. The use of Toxicity Equivalence Quantity (TEQ) concentration provide a better estimation of carcinogenicity activities; health risk to adults and children associated with PAHs inhalation was assessed by taking into account the lifetime average daily dose and corresponding incremental lifetime cancer risk (ILCR). The ILCR was within the acceptable range (10-6-10-4), indicating a low health risk to residents in these areas.

  8. Nitro Polycyclic Aromatic Hydrocarbons in Particulate Matter Emitted by the Combustion of Diesel and Biodiesel

    Science.gov (United States)

    Valle-Hernández, B. L.; Amador-Muñoz, O.; Jazcilevich, A. D.; Santos-Medina, G. L.; Hernández-Lopéz, E.; Villalobos-Pietrini, R.

    2013-05-01

    The rapid population growth in large urban areas, has resulted in a precipitous increase in the consumption of fossil fuels, mainly by the transport sector, diesel vehicles are a significant source of air pollution by particulate matter emissions, damaging the population health, because of the size and composition of these particles, as they may contain carcinogenic organic compounds such as polycyclic aromatic hydrocarbons and their derivatives, nitro-PAH. This study focused on analysis of nitro-PAH contained in particles emitted from diesel engines fuelled with biodiesel blends (B5, B10 and B16.67) to different driving cycles (rpm and torque), and to compare their concentrations with emissions from current diesel. A diesel truck engine was used in the laboratory for collect particulate mass emitted directly from the exhaust. Mass of particles and nitro-PAH were determined by gas chromatography-mass spectrometry using negative chemical ionization. No reduction was observed in the particles mass per second by using biodiesel relative to diesel (p > 0.1). Seven nitro-PAH were observed in samples: 1-nitronaphthalene, 2-nitronaphthalene, 9-nitroanthracene, 3-nitrophenanthrene, 1,8-dinitronaphthalene, 1-nitropyrene and 1,6-dinitropyrene. 1-nitropyrene showed the highest mass concentration in diesel and in all blends of biodiesel, followed by 3-nitrophenanthrene. Emissions reduction in biodiesel combustion with respect to diesel combustion were observed for 1-nitropyrene: 50 %, in all blends (B5, B10 and B16.67) and for 3-nitrophenanthrene: 55 % in B5, 72 % in B10 and 64 % in B16.67.

  9. Novel Approach for Evaluating Secondary Organic Aerosol from Aromatic Hydrocarbons: Unified Method for Predicting Aerosol Composition and Formation.

    Science.gov (United States)

    Li, Lijie; Tang, Ping; Nakao, Shunsuke; Kacarab, Mary; Cocker, David R

    2016-06-21

    Innovative secondary organic aerosol (SOA) composition analysis methods normalizing aerosol yield and chemical composition on an aromatic ring basis are developed and utilized to explore aerosol formation from oxidation of aromatic hydrocarbons. SOA yield and chemical composition are revisited using 15 years of University of California, Riverside/CE-CERT environmental chamber data on 17 aromatic hydrocarbons with HC:NO ranging from 11.1 to 171 ppbC:ppb. SOA yield is redefined in this work by normalizing the molecular weight of all aromatic precursors to the molecular weight of the aromatic ring [Formula: see text], where i is the aromatic hydrocarbon precursor. The yield normalization process demonstrates that the amount of aromatic rings present is a more significant driver of aerosol formation than the vapor pressure of the precursor aromatic. Yield normalization also provided a basis to evaluate isomer impacts on SOA formation. Further, SOA elemental composition is explored relative to the aromatic ring rather than on a classical mole basis. Generally, four oxygens per aromatic ring are observed in SOA, regardless of the alkyl substitutes attached to the ring. Besides the observed SOA oxygen to ring ratio (O/R ∼ 4), a hydrogen to ring ratio (H/R) of 6 + 2n is observed, where n is the number of nonaromatic carbons. Normalization of yield and composition to the aromatic ring clearly demonstrates the greater significance of aromatic ring carbons compared with alkyl carbon substituents in determining SOA formation and composition. PMID:27177154

  10. Degradation of benzene and other aromatic hydrocarbons by anaerobic bacteria

    OpenAIRE

    Weelink, S.A.B.

    2008-01-01

    Accidental spills, industrial discharges and gasoline leakage from underground storage tanks have resulted in serious pollution of the environment with monoaromatic hydrocarbons, such as benzene, toluene, ethylbenzene and xylene (so-called BTEX). High concentrations of BTEX have been detected in soils, sediments and groundwater. The mobility and toxicity of the BTEX compounds are of major concern. In situ bioremediation of BTEX by using naturally occurring microorganisms or introduced microor...

  11. Polycyclic Aromatic Hydrocarbon Residues in Serum Samples of Autopsied Individuals from Tennessee

    Directory of Open Access Journals (Sweden)

    Aramandla Ramesh

    2014-12-01

    Full Text Available This study reports the concentrations of Polycyclic Aromatic Hydrocarbons (PAHs in human blood sera samples (n = 650 obtained at autopsy from individuals who died of drug abuse, alcohol toxicity, homicide, suicide and other unknown causes. The analyzed samples from decedents revealed the presence of PAHs of which B(aP was the most predominant one, followed by benzo(bfluoranthene and benzo(kfluoranthene. The other PAHs detected sporadically and measured were benzo(g,h,iperylene, acenaphthene, anthracene, phenanthrene, and fluoranthene The mean concentrations of PAHs were greater in the twenties to fifties age groups compared to others. The PAH residue levels detected were high in African Americans compared to Caucasians, Asians, and Hispanics. It appears that environmental exposure, dietary intake and in some cases occupational exposure may have contributed to the PAH body burden. While the PAH residue concentrations measured fall within the range of those reported for healthy adults elsewhere, in isolated cases, the concentrations detected were high, calling the need for a reduction in PAH emissions and human biomonitoring studies for purposes of risk assessment.

  12. The Role of Polycyclic Aromatic Hydrocarbons in Ultraviolet Extinction. I. Probing small molecular PAHs

    CERN Document Server

    Clayton, G C; Witt, A N; Allamandola, L J; Martin, P G; Salama, F; Snow, T P; Whittet, D C B; Wolff, M J; Smith, T L; Clayton, Geoffrey C.; Gordon, Karl D.; Witt, Adolf N.; Martin, Peter G.; Wolff, Michael J.; Smith, Tracy L.

    2003-01-01

    We have obtained new STIS/HST spectra to search for structure in the ultraviolet interstellar extinction curve, with particular emphasis on a search for absorption features produced by polycyclic aromatic hydrocarbons (PAHs). The presence of these molecules in the interstellar medium has been postulated to explain the infrared emission features seen in the 3-13 $\\mu$m spectra of numerous sources. UV spectra are uniquely capable of identifying specific PAH molecules. We obtained high S/N UV spectra of stars which are significantly more reddened than those observed in previous studies. These data put limits on the role of small (30-50 carbon atoms) PAHs in UV extinction and call for further observations to probe the role of larger PAHs. PAHs are of importance because of their ubiquity and high abundance inferred from the infrared data and also because they may link the molecular and dust phases of the interstellar medium. A presence or absence of ultraviolet absorption bands due to PAHs could be a definitive te...

  13. Polycyclic aromatic hydrocarbon in rain and street runoff in Amman, Jordan

    Institute of Scientific and Technical Information of China (English)

    Anwar. G. Jiries; Helmi. H. Hussein; Jutta Lintelmann

    2003-01-01

    Concentrations of polycyclic aromatic hydrocarbons(PAHs) were determined in the rain and street runoff samples from two sites in the vicinity of Amman City during the pluvial period 1999-2000. The results showed that elevated levels of PAHs were detected in the city center(site 1 ) than the residential area(site 2) and that the levels were higher in street runoff than rain samples of the same sites.The highest concentration of PAHs in both street runoff and rain samples were observed in the first rainy month( November 1999) which indicated a wash out effect of PAHs originating from vehicular emission accumulated during the long dry summer season before sampling. Within the investigated cold winter seasons, fluctuations in PAHs concentration were observed. The variation was attributed to the fossil combustion for heating purposes and to intervals between rainfalls: as the longer the intervals between rains were, the higher the PAH concentration were.Removal of PAHs from the atmosphere through precipitation over the investigated period varied with time and places depending on the amount of rainfall where higher rainfall removed higher amount of PAHs from the atmosphere. The amount of PAHs washed out through precipitation was estimated to be around 14.8 mg/m2 and 21.1 mg/m2 for sites 1 and 2 respectively.

  14. Polycyclic aromatic hydrocarbon ionization as a tracer of gas flows through protoplanetary disk gaps

    CERN Document Server

    Maaskant, K M; Waters, L B F M; Tielens, A G G M

    2014-01-01

    Planet-forming disks of gas and dust around young stars contain polycyclic aromatic hydrocarbons (PAHs). We aim to characterize how the charge state of PAHs can be used as a probe of flows of gas through protoplanetary gaps. In this context, our goal is to understand the PAH spectra of four transitional disks. In addition, we want to explain the observed correlation between PAH ionization (traced by the 6.2/11.3 feature ratio) and the disk mass (traced by the 1.3 mm luminosity). We implement a model to calculate the charge state of PAHs in the radiative transfer code MCMax. The emission spectra and ionization balance are calculated. A benchmark modeling grid is presented that shows how PAH ionization and luminosity behave as a function of star and disk properties. The PAH ionization is most sensitive to ultraviolet (UV) radiation and the electron density. In optically thick disks, where the UV field is low and the electron density is high, PAHs are predominantly neutral. Ionized PAHs trace low-density optical...

  15. Assessing Photoinduced Toxicity of Polycyclic Aromatic Hydrocarbons in an Urbanized Estuary

    Directory of Open Access Journals (Sweden)

    S.P. Walker

    2004-12-01

    Full Text Available Increases in contaminants associated with urban sprawl are a particular concern in the rapidly developing coastal areas of the southeastern United States. Polycyclic aromatic hydrocarbons (PAHs are contaminants associated with vehicle emissions and runoff from impervious surfaces. Increased vehicular traffic and more impervious surfaces lead to an increased loading of PAHs into coastal estuarine systems. The phototoxic effect of PAH-contaminated sediments on a sediment-dwelling meiobenthic copepod, Amphiascus tenuiremis, was estimated in Murrells Inlet, a small, high-salinity estuary with moderate urbanization located in Georgetown and Horry Counties, South Carolina, USA. Field-determined solar ultraviolet radiation (UV and UV extinction coefficients were incorporated into laboratory toxicity experiments, and a model was developed to predict areas of specific hazard to A. tenuiremis in the estuary. The model incorporated laboratory toxicity data, UV extinction coefficients, and historical sediment chemistry and bathymetric data within a spatial model of sedimentary areas of the estuary. The model predicted that approximately 8–16% of the total creek habitat suitable for meiobenthic copepods is at risk to photoinduced PAH toxicity. This area is in the northern, more developed part of Murrells Inlet.

  16. Characterization of particulate polycyclic aromatic hydrocarbons in an urban atmosphere of central-southern Spain.

    Science.gov (United States)

    Villanueva, Florentina; Tapia, Araceli; Cabañas, Beatriz; Martínez, Ernesto; Albaladejo, José

    2015-12-01

    Over 1-year period, 13 polycyclic aromatic hydrocarbons (PAHs) associated with particulate matter PM10 have been monitored for the first time in the atmosphere of Ciudad Real, situated at the central-southern Spain. PM10-bound PAHs were collected using a high-volume sampler from autumn 2012 to summer 2013 and were analyzed by HPLC with fluorescence detector. The most abundant PAHs were pyrene, chrysene, benzo[b]fluoranthene, dibenzo[a,h]anthracene and benzo[g,h,i]perylene. The ∑PAH concentrations in Ciudad Real were 888, 368, 259 and 382 pg m(-3) for winter, spring, summer and autumn seasons, respectively. The diurnal variation of PAH was also investigated presenting the highest concentrations during the evening (19:00-23:00). Benzo[a]pyrene concentrations ranged from 2.4 to 110 pg m(-3), these values are lower than the target value proposed by the European legislation, 1 ng m(-3). Diagnostic ratios were used to identify potential sources of PAHs. Results suggest that vehicle emissions are the major source of identified PAHs, with a higher contribution of diesel engines although other anthropogenic sources could also have an impact on the PAH levels. PMID:26201660

  17. Geochemical distribution of polycyclic aromatic hydrocarbons in soils and sediments of El-Tabbin, Egypt.

    Science.gov (United States)

    Havelcová, Martina; Melegy, Ahmed; Rapant, Stanislav

    2014-01-01

    Polycyclic aromatic hydrocarbons (PAHs) were extracted from 30 samples (24 soils and 6 stream sediments) collected in El-Tabbin area in the southern part of Greater Cairo, Egypt. Isopleth maps of PAHs clarified the regional variability and identified the most affected regions in the area suffering from high pollution. The total PAH concentrations were 53.4-5558.0 ng g(-1) in the sample extracts. The highest values were found in a soil sample near a coke factory, with the highest concentration of single PAHs, which were 1064.8 ng g(-1) of fluoranthene and 1286.4 ng g(-1) of phenanthrene. The calculated ratios and indexes allowed to elucidate origin of the organic compounds and to identify emission sources. The overall molecular patterns are signatures of pyrolysis of fossil fuels and biomass. Petrogenic contamination was recognised in the sediment samples due to petroleum products deliveries from ships. Also perylene was prominent especially in samples of the River Nile sediments as a diagenetic product of fungi. Other detailed information on petrogenic sources was provided by analysis of alkanes and calculation of alkane ratios. PMID:24053943

  18. Characterization and distribution of polycyclic aromatic hydrocarbon in sediments of Haihe River, Tianjin, China

    Institute of Scientific and Technical Information of China (English)

    JIANG Bin; ZHENG Hai-long; HUANG Guo-qiang; DING Hui; LI Xin-gang; SUO Hong-tu; LI Rui

    2007-01-01

    In this study sediment samples were collected from 13 sites of Haihe River in Tianjin City,China,sixteen of priority polycyclic aromatic hydrocarbons(PAHs)listed in USEPA were analyzed by means of GC-MS.The total concentrations of PAH ranged from 774.81 to 255371.91 ng/g dw,and two to four rings of PAHs were dominant in sediment samples.Molecular ratios,such as phenanthrene/anthracene.fluoranthene/pyrene and low-molecular-weight PAH/high-molecular-weight PAH,were used to study the possible sources of pollution.It indicated a mixed pattem of parolytic and petrogenic inputs of PAHs in sediments in Haihe River.The petrogenic PAHs may be mainly derived from the leakage of refined products,e.g.,gasoline,diesel fuel and fuel oil vehicle traffics or gas stations from urban area.The pyrolytic PAHs might be from the discharge of industrial wastewater and the emission of atmospheric particles from petrochemical factories.In addition.the levels of PAHs in the urban and industrial areas are far beyond the values reported from other rivers and marine systems reported.This situation may be due to polluted discharging from some petrochemical industrial manufactories and worse traffiC conditions in Tianjin.

  19. Polycyclic Aromatic Hydrocarbons in Agricultural Soils of the Southern Subtropics, China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The contributions of persistent organic pollutants (POPs) from the subtropical regions of China to pollution of the global environment have been paid great attention; however, little is known about the state of POPs in agricultural ecosystems within these regions of China. This study primarily revealed the state of the contamination and distribution of polycyclic aromatic hydrocarbons (PAH) in agricultural soils in the subtropical regions. 115 surface soils (0-20 cm)were sampled in the breadbaskets of these regions. The concentrations and types of PAH were determined using gas chromatography linked to mass spectrometry (GC-MS). The total PAH concentrations ranged from 22.1 to 1256.9 ng g-1, with a mean of 318.2 ± 148.2 ng g-1. In general terms, the current PAH concentrations were lower than most PAH levels reported in a number of investigations from different countries and regions. PAH isomer ratios indicated that pyrolytic origins, such as fossil fuel combustion related to vehicle tail gas and industrial emissions, were the dominant sources of PAH in the southern subtropical areas of China. Although PAH concentrations decreased with decreasing pollution, population, and traffic density, to a great extent PAH compositions were similar throughout subtropical soils,with naphthalene, phenanthrene, fluoranthene, and benzo(b)fluoranthene being dominant.

  20. Human Health Risk Assessment of 16 Priority Polycyclic Aromatic Hydrocarbons in Soils of Chattanooga, Tennessee, USA.

    Science.gov (United States)

    Hussar, Erika; Richards, Sean; Lin, Zhi-Qing; Dixon, Robert P; Johnson, Kevin A

    2012-11-01

    South Chattanooga has been home to foundries, coke furnaces, chemical, wood preserving, tanning and textile plants for over 100 years. Most of the industries were in place before any significant development of residential property in the area. During the 1950s and 1960s, however, the government purchased inexpensive property and constructed public housing projects in South Chattanooga. Many neighborhoods that surround the Chattanooga Creek were previous dumping grounds for industry. Polycyclic aromatic hydrocarbons (PAHs) comprised the largest component of the dumping and airborne industrial emissions. To address the human exposure to these PAHs, a broad study of South Chattanooga soil contaminant concentrations was conducted on 20 sites across the city. Sixteen priority pollutant PAHs were quantified at two depths (0-10cm and 10-20cm) and compared against reference site soils, as well as to soils from industrially-impacted areas in Germany, China, and the US. From these data, the probability that people would encounter levels exceeding EPA Residential Preliminary Remediation Goals (PRG) was calculated. Results indicate that South Chattanooga soils have relatively high concentrations of total PAHs, specifically Benzo[a]pyrene (B[a]P). These high concentrations of B[a]P were somewhat ubiquitous in South Chattanooga. Indeed, there is a high probability (88%) of encountering soil in South Chattanooga that exceeds the EPA PRG for B[a]P. However, there is a low probability (15%) of encountering a site with ∑PAHs exceeding EPA PRG guidelines. PMID:23243323

  1. Investigation of sources of atmospheric polycyclic aromatic hydrocarbons at Mount Lushan in southern China

    Science.gov (United States)

    Li, Haiyan; Wang, Yan; Li, Hongli; Zhu, Chen; Mao, Huiting; Yang, Minmin; Wang, Ruixia; Wang, Wenxing

    2016-03-01

    Gaseous and particulate samples of polycyclic aromatic hydrocarbons (PAHs) were collected at the summit of Mount Lushan (29.58°N, 115.98°E, 1165 m asl) in southern China from August to September of 2011 and March to May of 2012 except special meteorological conditions such as rainy or very foggy days. The concentration of PAHs in total (gaseous and particulate PAHs) ranged from 15.79 to 160.53 ng m-3 (mean 41.67 ng m-3). Observed logarithmic values of particulate mass fraction (log θ) and partitioning coefficient (log Kp) were all higher than values calculated by the three gas-particle partitioning models, presenting higher fraction of particulate PAHs, indicating continual contribution of gaseous PAHs to particulate PAHs concentrations during long-range transport of air masses. Identified potential source regions using potential source contribution function analysis suggested significant contributions of emissions from coking, thermal power, and steel plants. The sources of PAHs levels at Mount Lushan that were identified using positive matrix factorization included diesel vehicles (43%), coal-fired boiler combustion (33%), coke oven source (17%), and incineration source (7%).

  2. Influence of traffic conditions on polycyclic aromatic hydrocarbon abundance in street dust.

    Science.gov (United States)

    Xiang, Li; Li, Yingxia; Yang, Zhifeng; Shi, Jianghong

    2010-01-01

    Polycyclic aromatic hydrocarbon (PAH) concentrations were quantified in sieved street dusts from eight sampling sites with different traffic conditions in Beijing. The parent diagnostic ratio test and multi-regression analysis were used to identify the different PAH pollution sources. Results showed that more than 93% of the cumulative 16 priority pollutant PAHs (Sigma 16EPA-PAH) load was present in street dust with a diameter less than 300 microm across all the sampling sites. The concentration of Sigma 4-6 ring PAHs was 93 to 284% higher than that of Sigma 2-3 ring PAHs for most of the sites except the cycle lane site, indicating the dominance of pyrogenic inputs in street dusts at these sites. Cooking oil is an important PAH source in street dusts for all the sampling sites. Tire debris and vehicle emissions were also identified as significant contributors to the PAH loading in the heavy traffic zone, vehicle parking areas, the frequent brake usage zone, and the construction area.

  3. Role of traffic in atmospheric accumulation of heavy metals and polycyclic aromatic hydrocarbons

    Science.gov (United States)

    Gunawardena, Janaka; Egodawatta, Prasanna; Ayoko, Godwin A.; Goonetilleke, Ashantha

    2012-07-01

    Traffic related emissions have been recognised as one of the main sources of air pollutants. In the research study discussed in this paper, variability of atmospheric total suspended particulate matter (TSP), polycyclic aromatic hydrocarbons (PAH) and heavy metal (HM) concentrations with traffic and land use characteristics during weekdays and weekends were investigated. Data required for the study were collected from a range of sampling sites to ensure a wide mix of traffic and land use characteristics. The analysis undertaken confirmed that zinc has the highest concentration in the atmospheric phase during weekends as well as weekdays. Although the use of leaded gasoline was discontinued a decade ago, lead was the second most commonly detected heavy metal. This is attributed to the association of previously generated lead with roadside soil and re-suspension to the atmosphere. Soil related particles are the primary source of TSP and manganese to the atmosphere. The analysis further revealed that traffic sources are dominant in gas phase PAHs compared to the other sources during weekdays. Land use related sources become important contributors to atmospheric PAHs during weekends when traffic sources are at their minimal levels.

  4. Evidence from SOFIA Imaging of Polycyclic Aromatic Hydrocarbon Formation along a Recent Outflow in NGC 7027

    Science.gov (United States)

    Lau, Ryan M.; Werner, Michael W.; Sahai, Raghvendra; Ressler, Michael E.

    2016-06-01

    We report spatially resolved (FWHM ~ 3.8 - 4.6'') mid-IR imaging observations of the planetary nebula (PN) NGC 7027 taken with the 2.5-m telescope aboard the Stratospheric Observatory for Infrared Astronomy (SOFIA). Images of NGC 7027 were acquired at 6.3, 6.6, 11.1, 19.7, 24.2, 33.6, and 37.1 μm using the Faint Object Infrared Camera for the SOFIA Telescope (FORCAST). The observations reveal emission from Polycyclic Aromatic Hydrocarbon (PAH) and warm dust (TD ~ 90 K) from the ionized inner edge of the molecular envelope surrounding the central star of the planetary nebula (CSPN). The DustEM code was used to fit the spectral energy distribution of fluxes obtained by FORCAST and the archival infrared spectrum of NGC 7027 acquired by the Short Wavelength Spectrometer (SWS) on the Infrared Space Observatory (ISO). Best-fit dust models reveal a total dust mass of ~6 × 10-3 M⊙, where carbonaceous large (a = 1.5 μm) and very small (a ~ 12 Å) grains, and PAHs (3.1 Å photo-dissociation region (PDR) and molecular envelope.

  5. Anthropogenic input of polycyclic aromatic hydrocarbons into five lakes in Western China

    Energy Technology Data Exchange (ETDEWEB)

    Guo, J.Y.; Wu, F.C.; Luo, X.J.; Liang, Z.; Liao, H.Q.; Zhang, R.Y.; Li, W.; Zhao, X.L.; Chen, S.J.; Mai, B.X. [Chinese Research Institute of Environmental Science, Beijing (China)

    2010-06-15

    The temporal distribution of polycyclic aromatic hydrocarbons (PAHs) was examined in dated sediments from five lakes in Western China. The surficial concentrations of seven carcinogenic PAHs (BaA, Chyr, BbF, BkF, BaP, DBA and INP, hereafter denoted as PAH(7)) were highly site-specific. The {Sigma}PAH(7) concentrations generally increased from the deep layers to surface sediments. The temporal trends of {Sigma} PAH(7) concentrations were clearly different from those reported in developed countries. From 1950s to 19805, which PAHs started to decrease in developed countries, is the right period that PAHs started to increase rapidly in Western China. The fluxes and mass inventories suggest that the PAH(7) input over the past three decades was much more rapidly than it was before the 1980s. Source identification indicates that the PAHs were primarily from biomass burning and domestic coal combustion, and increasing vehicular and/or industrial coal combustion emission was also found.

  6. Evidence from SOFIA Imaging of Polycyclic Aromatic Hydrocarbon Formation along a Recent Outflow in NGC 7027

    CERN Document Server

    Lau, R M; Sahai, R; Ressler, M E

    2016-01-01

    We report spatially resolved (FWHM$\\sim3.8-4.6"$) mid-IR imaging observations of the planetary nebula (PN) NGC 7027 taken with the 2.5-m telescope aboard the Stratospheric Observatory for Infrared Astronomy (SOFIA). Images of NGC 7027 were acquired at 6.3, 6.6, 11.1, 19.7, 24.2, 33.6, and 37.1 $\\mu\\mathrm{m}$ using the Faint Object Infrared Camera for the SOFIA Telescope (FORCAST).The observations reveal emission from Polycyclic Aromatic Hydrocarbon (PAH) and warm dust ($T_D\\sim90$ K) from the illuminated inner edge of the molecular envelope surrounding the ionized gas and central star. The DustEM code was used to fit the spectral energy distribution of fluxes obtained by FORCAST and the archival infrared spectrum of NGC 7027 acquired by the Short Wavelength Spectrometer (SWS) on the Infrared Space Observatory (ISO). Best-fit dust models provide a total dust mass of $5.8^{+2.3}_{-2.6}\\times10^{-3}$ $\\mathrm{M}_\\odot$, where carbonaceous large ($a=1.5$ $\\mu$m) and very small ($a \\sim12\\AA$) grains, and PAHs ($...

  7. Estrogenic Activity of Mineral Oil Aromatic Hydrocarbons Used in Printing Inks.

    Directory of Open Access Journals (Sweden)

    Patrick Tarnow

    Full Text Available The majority of printing inks are based on mineral oils (MOs which contain complex mixtures of saturated and aromatic hydrocarbons. Consumer exposure to these oils occurs either through direct skin contacts or, more frequently, as a result of MO migration into the contents of food packaging that was made from recycled newspaper. Despite this ubiquitous and frequent exposure little is known about the potential toxicological effects, particularly with regard to the aromatic MO fractions. From a toxicological point of view the huge amount of alkylated and unsubstituted compounds therein is reason for concern as they can harbor genotoxicants as well as potential endocrine disruptors. The aim of this study was to assess both the genotoxic and estrogenic potential of MOs used in printing inks. Mineral oils with various aromatic hydrocarbon contents were tested using a battery of in vitro assays selected to address various endpoints such as estrogen-dependent cell proliferation, activation of estrogen receptor α or transcriptional induction of estrogenic target genes. In addition, the comet assay has been applied to test for genotoxicity. Out of 15 MOs tested, 10 were found to potentially act as xenoestrogens. For most of the oils the effects were clearly triggered by constituents of the aromatic hydrocarbon fraction. From 5 oils tested in the comet assay, 2 showed slight genotoxicity. Altogether it appears that MOs used in printing inks are potential endocrine disruptors and should thus be assessed carefully to what extent they might contribute to the total estrogenic burden in humans.

  8. Polycyclic aromatic hydrocarbons and molecular hydrogen in oxygen-rich planetary nebulae: the case of NGC6720

    CERN Document Server

    Cox, N L J; Berne, O; Cernicharo, J; Joblin, C

    2015-01-01

    Evolved stars are primary sources for the formation of polycyclic aromatic hydrocarbons (PAHs) and dust grains. Their circumstellar chemistry is usually designated as either oxygen-rich or carbon-rich, although dual-dust chemistry objects, whose infrared spectra reveal both silicate- and carbon-dust features, are also known. The exact origin and nature of this dual-dust chemistry is not yet understood. Spitzer-IRS mid-infrared spectroscopic imaging of the nearby, oxygen-rich planetary nebula NGC6720 reveals the presence of the 11.3 micron aromatic (PAH) emission band. It is attributed to emission from neutral PAHs, since no band is observed in the 7 to 8 micron range. The spatial distribution of PAHs is found to closely follow that of the warm clumpy molecular hydrogen emission. Emission from both neutral PAHs and warm H2 is likely to arise from photo-dissociation regions associated with dense knots that are located within the main ring. The presence of PAHs together with the previously derived high abundance...

  9. Fingerprints of polycyclic aromatic hydrocarbons (PAHs) in infrared absorption spectroscopy

    Science.gov (United States)

    Tommasini, Matteo; Lucotti, Andrea; Alfè, Michela; Ciajolo, Anna; Zerbi, Giuseppe

    2016-01-01

    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.

  10. Source Identification of Polycyclic Aromatic Hydrocarbons by Diagnostic Ratios and Positive Matrix Factorization

    Science.gov (United States)

    Dvorska, A.; Jarkovsky, J.; Lammel, G.; Klanova, J.

    2009-04-01

    Although polycyclic aromatic hydrocarbons (PAHs) are also of natural origin, in many regions their environmental concentrations have strongly increased due to human activities. These semivolatile organic compounds are generally formed during incomplete combustion. Other sources include volatilization from unburned petroleum or tire abrasion in road traffic. Among all pollutants PAHs pose the highest human health hazard in Europe (WHO, 2003). A multivariate statistical method, positive matrix factorization (PMF; Paatero, 1997), and diagnostic ratios of individual PAHs (e.g. Yunker et al., 2002) are used for PAH source identification in central Europe. To minimise confounding factors such as differences in volatility, water solubility, adsorption etc., diagnostic ratios should be restricted to PAHs of similar molecular mass (Readman et al., 1987). Furthermore, different reactivities are limiting. Nevertheless, the application of PAH diagnostic ratios is often inconclusive, because substance patterns (profiles) have not been reported for all sources and ranges for various sources overlap. The complete profiles are made use of by statistical methods such as factor analysis, UNMIX and PMF (Tauler et al., 2006). However, these methods can be unreliable, because of incomplete knowledge of source profiles and the analysis' sensitivity to the data distribution. A unique 12-year data set of concentrations of PAHs (16 individual substances, 2 phases, weekly) in air, measured at the regional observatory Košetice, Czech Republic, is examined, together with shorter time series from Leipzig (urban background) and Schwartenberg (subalpine mountain background), Germany. Also, retene and coronene as specific source markers measured in Košetice from 2006 on are included into the analysis. An extensive literature search on PAH emission profiles was conducted. This data set was accomplished by measurements at sites in the Zlínsko region, Czech Republic, which are strongly dominated

  11. The Dose–Response Decrease in Heart Rate Variability: Any Association with the Metabolites of Polycyclic Aromatic Hydrocarbons in Coke Oven Workers?

    OpenAIRE

    Xiaohai Li; Yingying Feng; Huaxin Deng; Wangzhen Zhang; Dan Kuang; Qifei Deng; Xiayun Dai; Dafeng Lin; Suli Huang; Lili Xin; Yunfeng He; Kun Huang; Meian He; Huan Guo; Xiaomin Zhang

    2012-01-01

    BACKGROUND: Air pollution has been associated with an increased risk of cardiopulmonary mortality and decreased heart rate variability (HRV). However, it is unclear whether coke oven emissions (COEs) and polycyclic aromatic hydrocarbons (PAHs) are associated with HRV. OBJECTIVES: Our goal in the present study was to investigate the association of exposure to COEs and the urinary metabolite profiles of PAHs with HRV of coke oven workers. METHODS: We measured benzene soluble matter, carbon mono...

  12. Reconstructing historical trends of polycyclic aromatic hydrocarbon deposition in a remote area of Spain using herbarium moss material

    Science.gov (United States)

    Foan, L.; Sablayrolles, C.; Elustondo, D.; Lasheras, E.; González, L.; Ederra, A.; Simon, V.; Santamaría, J. M.

    2010-08-01

    Herbarium mosses from 1879-1881, 1973-1975 and 2006-2007 were used to investigate the historical changes of atmospheric deposition of polycyclic aromatic hydrocarbons (PAHs) at a remote site in Northern Spain. Natural abundance of nitrogen and carbon isotopes was also measured in order to assess the evolution of emissions from anthropogenic sources. Nitrogen and PAH concentrations as well as δ 13C and δ 15N ratios were significantly higher in 19th century samples compared to present century samples. Moreover, PAH distribution varied over the centuries, with the trend towards enrichment in light PAHs. The carbon, nitrogen and PAH concentrations measured in the mosses tally with the historical evolution of anthropogenic emissions in the area, mainly influenced by changes in economic activities, domestic heating and road traffic density. Mosses provided by herbaria seem to offer the possibility of studying long-term temporal evolution of atmospheric PAH deposition.

  13. Analysis of diesel particulate: influence of air-fuel ratio and fuel composition on polycyclic aromatic hydrocarbon content

    Energy Technology Data Exchange (ETDEWEB)

    Lombaert, K.; le Moyne, L.; Maleissye, Tardieu de [Universite Pierre et Marie Curie, Lab. de Mecanique Physique, Saint Cyr l' Ecole (France); Amouroux, J. [Ecole Nationale Superieure de Chimie, Lab. de Genie des Procedes Plasmas, Paris (France)

    2002-06-01

    Polycyclic aromatic hydrocarbons (PAH) are pollutants produced during the combustion process and are considered as soot precursors. PAH emissions are not presently regulated although they may have dangerous effects on human health. A comparison is presented here of the influence of engine parameters (air-fuel ratio and brake mean effective pressure) on the composition of particulates. The effects of a water-fuel emulsion on PAH (commonly examined in large engines) are also studied in a 1.9 L commonrail diesel engine: 13 per cent of water added to the fuel decreases the PAH concentration in diesel soot by half. The PAH emissions during cold-start of an automotive diesel engine are also presented. (Author)

  14. Mechanistic studies on the OH-initiated atmospheric oxidation of selected aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Nehr, Sascha

    2012-07-01

    Benzene, toluene, the xylenes, and the trimethylbenzenes are among the most abundant aromatic trace constituents of the atmosphere mainly originating from anthropogenic sources. The OH-initiated atmospheric photo-oxidation of aromatic hydrocarbons is the predominant removal process resulting in the formation of O{sub 3} and secondary organic aerosol. Therefore, aromatics are important trace constituents regarding air pollution in urban environments. Our understanding of aromatic photo-oxidation processes is far from being complete. This work presents novel approaches for the investigation of OH-initiated atmospheric degradation mechanisms of aromatic hydrocarbons. Firstly, pulsed kinetic studies were performed to investigate the prompt HO{sub 2} formation from OH+ aromatic hydrocarbon reactions under ambient conditions. For these studies, the existing OH reactivity instrument, based on the flash photolysis/laser-induced fluorescence (FP/LIF) technique, was extended to the detection of HO{sub 2} radicals. The experimental design allows for the determination of HO{sub 2} formation yields and kinetics. Results of the pulsed kinetic experiments complement previous product studies and help to reduce uncertainties regarding the primary oxidation steps. Secondly, experiments with aromatic hydrocarbons were performed under atmospheric conditions in the outdoor atmosphere simulation chamber SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction chamber) located at Forschungszentrum Juelich. The experiments were aimed at the evaluation of up-to-date aromatic degradation schemes of the Master Chemical Mechanism (MCMv3.2). The unique combination of analytical instruments operated at SAPHIR allows for a detailed investigation of HO{sub x} and NO{sub x} budgets and for the determination of primary phenolic oxidation product yields. MCMv3.2 deficiencies were identified and most likely originate from shortcomings in the mechanistic representation of ring

  15. On the aliphatic versus aromatic content of the carriers of the `unidentified' infrared emission features

    Science.gov (United States)

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

    2016-10-01

    Although it is generally accepted that the unidentified infrared emission (UIE) features at 3.3, 6.2, 7.7, 8.6, and 11.3 μm are characteristic of the stretching and bending vibrations of aromatic hydrocarbon materials, the exact nature of their carriers remains unknown: whether they are free-flying, predominantly aromatic gas-phase molecules, or amorphous solids with a mixed aromatic/aliphatic composition are being debated. Recently, the 3.3 and 3.4 μm features which are commonly respectively attributed to aromatic and aliphatic C-H stretches have been used to place an upper limit of ˜2 per cent on the aliphatic fraction of the UIE carriers (i.e. the number of C atoms in aliphatic chains to that in aromatic rings). Here we further explore the aliphatic versus aromatic content of the UIE carriers by examining the ratio of the observed intensity of the 6.2 μm aromatic C-C feature (I6.2) to that of the 6.85 μm aliphatic C-H deformation feature (I6.85). To derive the intrinsic oscillator strengths of the 6.2 μm stretch (A6.2) and the 6.85 μm deformation (A6.85), we employ density functional theory to compute the vibrational spectra of seven methylated polycyclic aromatic hydrocarbon molecules and their cations. By comparing I6.85/I6.2 with A6.85/A6.2, we derive the fraction of C atoms in methyl(ene) aliphatic form to be at most ˜10 per cent, confirming the earlier finding that the UIE emitters are predominantly aromatic. We have also computed the intrinsic strength of the 7.25 μm feature (A7.25), another aliphatic C-H deformation band. We find that A6.85 appreciably exceeds A7.25. This explains why the 6.85 μm feature is more frequently detected in space than the 7.25 μm feature.

  16. THE ABUNDANCES OF HYDROCARBON FUNCTIONAL GROUPS IN THE INTERSTELLAR MEDIUM INFERRED FROM LABORATORY SPECTRA OF HYDROGENATED AND METHYLATED POLYCYCLIC AROMATIC HYDROCARBONS

    Energy Technology Data Exchange (ETDEWEB)

    Steglich, M.; Jäger, C.; Huisken, F. [Laboratory Astrophysics Group of the Max Planck Institute for Astronomy at the Friedrich Schiller University Jena, Institute of Solid State Physics, Helmholtzweg 3, D-07743 Jena (Germany); Friedrich, M.; Plass, W. [Institute of Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Humboldtstraße 8, D-07743 Jena (Germany); Räder, H.-J.; Müllen, K. [Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz (Germany); Henning, Th., E-mail: M.Steglich@web.de [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany)

    2013-10-01

    Infrared (IR) absorption spectra of individual polycyclic aromatic hydrocarbons (PAHs) containing methyl (-CH{sub 3}), methylene (CH{sub 2}), or diamond-like CH groups and IR spectra of mixtures of methylated and hydrogenated PAHs prepared by gas-phase condensation were measured at room temperature (as grains in pellets) and at low temperature (isolated in Ne matrices). In addition, the PAH blends were subjected to an in-depth molecular structure analysis by means of high-performance liquid chromatography, nuclear magnetic resonance spectroscopy, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Supported by calculations at the density functional theory level, the laboratory results were applied to analyze in detail the aliphatic absorption complex of the diffuse interstellar medium at 3.4 μm and to determine the abundances of hydrocarbon functional groups. Assuming that the PAHs are mainly locked in grains, aliphatic CH {sub x} groups (x = 1, 2, 3) would contribute approximately in equal quantities to the 3.4 μm feature (N {sub CHx}/N {sub H} ≈ 10{sup –5}-2 × 10{sup –5}). The abundances, however, may be two to four times lower if a major contribution to the 3.4 μm feature comes from molecules in the gas phase. Aromatic ≅CH groups seem to be almost absent from some lines of sight, but can be nearly as abundant as each of the aliphatic components in other directions (N{sub ≅CH}/N {sub H} ∼< 2 × 10{sup –5}; upper value for grains). Due to comparatively low binding energies, astronomical IR emission sources do not display such heavy excess hydrogenation. At best, especially in protoplanetary nebulae, CH{sub 2} groups bound to aromatic molecules, i.e., excess hydrogens on the molecular periphery only, can survive the presence of a nearby star.

  17. Evaluating the Effects of Aromatics Content in Gasoline on Gaseous and Particulate Matter Emissions from SI-PFI and SIDI Vehicles.

    Science.gov (United States)

    Karavalakis, Georgios; Short, Daniel; Vu, Diep; Russell, Robert; Hajbabaei, Maryam; Asa-Awuku, Akua; Durbin, Thomas D

    2015-06-01

    We assessed the emissions response of a fleet of seven light-duty gasoline vehicles for gasoline fuel aromatic content while operating over the LA92 driving cycle. The test fleet consisted of model year 2012 vehicles equipped with spark-ignition (SI) and either port fuel injection (PFI) or direct injection (DI) technology. Three gasoline fuels were blended to meet a range of total aromatics targets (15%, 25%, and 35% by volume) while holding other fuel properties relatively constant within specified ranges, and a fourth fuel was formulated to meet a 35% by volume total aromatics target but with a higher octane number. Our results showed statistically significant increases in carbon monoxide, nonmethane hydrocarbon, particulate matter (PM) mass, particle number, and black carbon emissions with increasing aromatics content for all seven vehicles tested. Only one vehicle showed a statistically significant increase in total hydrocarbon emissions. The monoaromatic hydrocarbon species that were evaluated showed increases with increasing aromatic content in the fuel. Changes in fuel composition had no statistically significant effect on the emissions of nitrogen oxides (NOx), formaldehyde, or acetaldehyde. A good correlation was also found between the PM index and PM mass and number emissions for all vehicle/fuel combinations with the total aromatics group being a significant contributor to the total PM index followed by naphthalenes and indenes.

  18. Monitoring of polycyclic aromatic hydrocarbons in seafoods from Lake Timsah.

    Science.gov (United States)

    Mostafa, Gamal A

    2002-03-01

    Concentrations of polycyclic aromatic hydrpcarvons (PAHs) in some seafoods caught from Lake Timsah were determined. The tested samples were tilapia fish (Oreochromis aureus), crabs (Portuns pelagicus), bivalves (Venerupis decussata), clams (Strombus tricornis) and gastropods (Munes Sp.). Where these seafoods are locally and favorite consumed foods in the area around the lake (Ismailia governorate). Results showed that crabs contained significantly higher concentrations of both total and carcinogenic PAHs ranging from 1318.6 to 3767.4 and 1230.3 to 3442.2 microg kg(-1), respectively. Meanwhile, clams contained significantly lower levels with mean value of 28.4 microg kg(-1) for total and 24.4 microg kg(-1) for carcinogenic PAHs. The most frequently detected PAHs in the tested samples were indeno(1,2,3-cd)pyrene followed by benzo(a)pyrene, dibenzo(a,h)anthracene, and benzo(b)fluoranthene which are characterized as carcinogenic compounds. PMID:11970818

  19. Impact and uncertainty of a traffic management intervention: Population exposure to polycyclic aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Vardoulakis, Sotiris [Public and Environmental Health Research Unit, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT (United Kingdom)], E-mail: sotiris.vardoulakis@lshtm.ac.uk; Chalabi, Zaid; Fletcher, Tony; Grundy, Chris [Public and Environmental Health Research Unit, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT (United Kingdom); Leonardi, Giovanni S. [Centre for Radiation, Chemical, and Environmental Hazards, Health Protection Agency, Chilton, Didcot, Oxfordshire OX11 0RQ (United Kingdom)

    2008-05-15

    In urban areas, road traffic is a major source of carcinogenic polycyclic aromatic hydrocarbons (PAH), thus any changes in traffic patterns are expected to affect PAH concentrations in ambient air. Exposure to PAH and other traffic-related air pollutants has often been quantified in a deterministic manner that disregards the various sources of uncertainty in the modelling systems used. In this study, we developed a generic method for handling uncertainty in population exposure models. The method was applied to quantify the uncertainty in population exposure to benzo[a]pyrene (BaP) before and after the implementation of a traffic management intervention. This intervention would affect the movement of vehicles in the studied area and consequently alter traffic emissions, pollutant concentrations and population exposure. Several models, including an emission calculator, a dispersion model and a Geographic Information System were used to quantify the impact of the traffic management intervention. We established four exposure zones defined by distance of residence postcode centroids from major road or intersection. A stochastic method was used to quantify the uncertainty in the population exposure model. The method characterises uncertainty using probability measures and propagates it applying Monte Carlo analysis. The overall model predicted that the traffic management scheme would lead to a minor reduction in mean population exposure to BaP in the studied area. However, the uncertainty associated with the exposure estimates was much larger than this reduction. The proposed method is generic and provides realistic estimates of population exposure to traffic-related pollutants, as well as characterises the uncertainty in these estimates. This method can be used within a decision support tool to evaluate the impact of alternative traffic management policies.

  20. Global fate and distribution of polycyclic aromatic hydrocarbons emitted from Europe and Russia

    Science.gov (United States)

    Sehili, Aissa M.; Lammel, Gerhard

    The long-range atmospheric transport (LRT) of polycyclic aromatic hydrocarbons (PAHs) is not fully understood and has hardly been addressed by model studies. By model experiments the LRT of PAH emissions into air from Europe and Russia is studied testing several scenarios of gas-particle partitioning and degradability by reaction with ozone and the hydroxyl and nitrate radicals for two PAHs, benzo[a]pyrene (BAP) and fluoranthene (FLT). The model used is the atmosphere general circulation model ECHAM5 with a dynamic modal aerosol sub-model, HAM, ozone and sulfur species chemistry and bidirectional mass exchange on 2D marine (ocean surface mixed layer) and terrestrial surfaces (top soil layer and vegetation surfaces). After 5 years the substances are found to be mostly distributed to the soil compartment (64-97% as the global mean, varying with substance and season), which after 10 years is still filling; 1-5% are found in air and 2-33% in ocean. It is found that the lifetime and vertical distribution of the substances in the atmosphere and the LRT potential are all significantly influenced by the partitioning and degradation scenario. The total environmental burden is higher when sorption to organic matter and black carbon are considered to determine gas-particle partitioning rather than adsorption to the surface of particulate matter. The effect is +20% for BAP but sevenfold for FLT. Concentrations in Arctic air are mostly underestimated by the model, which is partly explained by emissions not considered in the simulation. The comparison shows, however, that degradation of the sorbed BAP and FLT molecules should be significantly slower than the respective gaseous molecules and that absorptive partitioning is necessary to explain the LRT potential of FLT.

  1. Impact and uncertainty of a traffic management intervention: Population exposure to polycyclic aromatic hydrocarbons

    International Nuclear Information System (INIS)

    In urban areas, road traffic is a major source of carcinogenic polycyclic aromatic hydrocarbons (PAH), thus any changes in traffic patterns are expected to affect PAH concentrations in ambient air. Exposure to PAH and other traffic-related air pollutants has often been quantified in a deterministic manner that disregards the various sources of uncertainty in the modelling systems used. In this study, we developed a generic method for handling uncertainty in population exposure models. The method was applied to quantify the uncertainty in population exposure to benzo[a]pyrene (BaP) before and after the implementation of a traffic management intervention. This intervention would affect the movement of vehicles in the studied area and consequently alter traffic emissions, pollutant concentrations and population exposure. Several models, including an emission calculator, a dispersion model and a Geographic Information System were used to quantify the impact of the traffic management intervention. We established four exposure zones defined by distance of residence postcode centroids from major road or intersection. A stochastic method was used to quantify the uncertainty in the population exposure model. The method characterises uncertainty using probability measures and propagates it applying Monte Carlo analysis. The overall model predicted that the traffic management scheme would lead to a minor reduction in mean population exposure to BaP in the studied area. However, the uncertainty associated with the exposure estimates was much larger than this reduction. The proposed method is generic and provides realistic estimates of population exposure to traffic-related pollutants, as well as characterises the uncertainty in these estimates. This method can be used within a decision support tool to evaluate the impact of alternative traffic management policies

  2. Polycyclic aromatic hydrocarbons (PAHs in the atmospheres of two French alpine valleys: sources and temporal patterns

    Directory of Open Access Journals (Sweden)

    N. Marchand

    2004-01-01

    Full Text Available Alpine valleys represent some of the most important crossroads for international heavy-duty traffic in Europe, but the full impact of this traffic on air quality is not known due to a lack of data concerning these complex systems. As part of the program "Pollution des Vallées Alpines" (POVA, we performed two sampling surveys of polycyclic aromatic hydrocarbons (PAHs in two sensitive valleys: the Chamonix and Maurienne Valleys, between France and Italy. Sampling campaigns were performed during the summer of 2000 and the winter of 2001, with both periods taking place during the closure of the "Tunnel du Mont-Blanc". The first objective of this paper is to describe the relations between PAH concentrations, external parameters (sampling site localization, meteorological parameters, sources, and aerosol characteristics, including its carbonaceous fraction (OC and EC. The second objective is to study the capacity of PAH profiles to accurately distinguish the different emission sources. Temporal evolution of the relative concentration of an individual PAH (CHR and the PAH groups BghiP+COR and BbF+BkF is studied in order to differentiate wood combustion, gasoline, and diesel emissions, respectively. The results show that the total particulate PAH concentrations were higher in the Chamonix valley during both seasons, despite the cessation of international traffic. Seasonal cycles, with higher concentrations in winter, are also stronger in this valley. During winter, particulate PAH concentration can reach very high levels (up to 155 ng.m-3 in this valley during cold anticyclonic periods. The examination of sources shows the impact during summer of heavy-duty traffic in the Maurienne valley and of gasoline vehicles in the Chamonix valley. During winter, Chamonix is characterized by the strong influence of wood combustion in residential fireplaces, even if the temporal evolution of specific PAH ratios are difficult to interpret. Information on sources

  3. IUPAC-NIST Solubility Data Series. 101. Alcohols + Hydrocarbons + Water Part 3. C1-C3 Alcohols + Aromatic Hydrocarbons

    Science.gov (United States)

    Oracz, Paweł; Góral, Marian; Wiśniewska-Gocłowska, Barbara; Shaw, David G.; Mączyński, Andrzej

    2016-09-01

    The mutual solubilities and related liquid-liquid equilibria for 11 ternary systems of C1-C3 alcohols with aromatic hydrocarbons and water are exhaustively and critically reviewed. Reports of experimental determination of solubility that appeared in the primary literature prior to the end of 2012 are compiled. For nine systems, sufficient data are available (two or more independent determinations) to allow critical evaluation. All new data are expressed as mass percent and mole fraction as well as the originally reported units. In addition to the standard evaluation criteria used throughout the Solubility Data Series, an additional criterion was used for each of the evaluated systems. These systems include one binary miscibility gap in the hydrocarbon + water subsystem. The binary tie lines were compared with the recommended values published previously.

  4. Polycyclic aromatic hydrocarbons affect survival and development of common snapping turtle (Chelydra serpentina) embryos and hatchlings

    Energy Technology Data Exchange (ETDEWEB)

    Van Meter, Robin J. [School of Environmental Science, Engineering, and Policy and Department of Bioscience and Biotechnology, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104 (United States)]. E-mail: robinjvanmeter@yahoo.com; Spotila, James R. [School of Environmental Science, Engineering, and Policy and Department of Bioscience and Biotechnology, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104 (United States)]. E-mail: spotiljr@drexel.edu; Avery, Harold W. [School of Environmental Science, Engineering, and Policy and Department of Bioscience and Biotechnology, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104 (United States)]. E-mail: Haltort@aol.com

    2006-08-15

    Polycyclic aromatic hydrocarbons (PAHs) are toxic compounds found in the John Heinz National Wildlife Refuge in Philadelphia, Pennsylvania. We assessed the impact of PAHs and crude oil on snapping turtle development and behavior by exposing snapping turtle eggs from the Refuge and from three clean reference sites to individual PAHs or a crude oil mixture at stage 9 of embryonic development. Exposure to PAHs had a significant effect on survival rates in embryos from one clean reference site, but not in embryos from the other sites. There was a positive linear relationship between level of exposure to PAHs and severity of deformities in embryos collected from two of the clean reference sites. Neither righting response nor upper temperature tolerance (critical thermal maximum, CTM) of snapping turtle hatchlings with no or minor deformities was significantly affected by exposure to PAHs. - Exposure to polycyclic aromatic hydrocarbons on the egg reduces survival of snapping turtle embryos and causes developmental abnormalities.

  5. Thyroid hormone binding proteins as novel targets for hydroxylated polyhalogenated aromatic hydrocarbons (PHAHs): possible implications for toxicity.

    NARCIS (Netherlands)

    Lans, M.C.

    1995-01-01

    Some toxic effects caused by polyhalogenated aromatic hydrocarbons (PHAHs) develop through alterations in the reproductive and thyroid hormone regulatory systems, thereby affecting (brain) development, reproduction and behaviour of several species (Stone, 1995, Birnbaum, 1994, for review: Brouwer et

  6. FORMATION OF POLYCYCLIC AROMATIC HYDROCARBONS AND THEIR GROWTH TO SOOT -A REVIEW OF CHEMICAL REACTION PATHWAYS. (R824970)

    Science.gov (United States)

    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...

  7. Enumeration and phylogenetic analysis of polycyclic aromatic hydrocarbon-degrading marine bacteria from Puget sound sediments.

    OpenAIRE

    Geiselbrecht, A D; Herwig, R P; Deming, J. W.; Staley, J T

    1996-01-01

    Naphthalene- and phenanthrene-degrading bacteria in Puget Sound sediments were enumerated by most-probable-number enumeration procedures. Sediments from a creosote-contaminated Environmental Protection Agency Superfund Site (Eagle Harbor) contained from 10(4) to 10(7) polycyclic aromatic hydrocarbon (PAH)-degrading bacteria g (dry weight) of sediment-1, whereas the concentration at an uncontaminated site ranged from 10(3) to 10(4) g of sediment(-1). Isolates of PAH-degrading bacteria were obt...

  8. Polycyclic Aromatic Hydrocarbon Degradation by a New Marine Bacterium, Neptunomonas naphthovorans gen. nov., sp. nov.

    OpenAIRE

    Hedlund, Brian P.; Geiselbrecht, Allison D.; Bair, Timothy J.; Staley, James T.

    1999-01-01

    Two strains of bacteria were isolated from creosote-contaminated Puget Sound sediment based on their ability to utilize naphthalene as a sole carbon and energy source. When incubated with a polycyclic aromatic hydrocarbon (PAH) compound in artificial seawater, each strain also degraded 2-methylnaphthalene and 1-methylnaphthalene; in addition, one strain, NAG-2N-113, degraded 2,6-dimethylnaphthalene and phenanthrene. Acenaphthene was not degraded when it was used as a sole carbon source but wa...

  9. Genotoxicity in child populations exposed to Polycyclic Aromatic Hydrocarbons (PAHs) in the air from Tabasco, Mexico

    OpenAIRE

    Gamboa, Aldeco R.; Rodríguez T. Gamboa; Bravo, Alvarez H.; Wegman P. Ostrosky

    2008-01-01

    The economy of the state of Tabasco is based on oil extraction. However, this imposes major effects to the environment and communities. Examples are the Polycyclic Aromatic Hydrocarbons (PAHs) that may be found in the soil, water and sediment of the region. Their volatility makes them available to living beings and results in genotoxic activity. The purpose of this study was to quantify the levels of PAHs in the air at several points in the state, and to analyze their relationship with possib...

  10. Sexual maturation in relation to polychlorinated aromatic hydrocarbons: Sharpe and Skakkebaek's hypothesis revisited

    OpenAIRE

    Den Hond, Elly; Roels, Harry A.; Hoppenbrouwers, Karel; Nawrot, Tim; Thijs, Lutgarde; Vandermeulen, Corinne; Winneke, Gerhard; Vanderschueren, Dirk; Staessen, Jan A.

    2002-01-01

    Polychlorinated aromatic hydrocarbons (PCAHs) have been described as endocrine disruptors in animals and in accidentally or occupationally exposed humans. In the present study we examined the effect of moderate exposure to PCAHs on sexual maturation. Two hundred adolescents (mean age, 17.4 years) who resided in two polluted suburbs and a rural control area in Flanders (Belgium) participated. We measured the serum concentration of polychlorinated biphenyl (PCB) congeners 138, 153, and 180 and ...

  11. Molecular comparison of cultivable protozoa from a pristine and a polycyclic aromatic hydrocarbon polluted site

    OpenAIRE

    Lara, Enrique; Berney, Cédric; Ekelund, Flemming; Harms, Hauke; Chatzinotas, Antonis

    2010-01-01

    We compared the abundance and diversity of cultivable protozoa (flagellates and amoebae) in a polycyclic aromatic hydrocarbon (PAH) polluted soil and an unpolluted control, by isolating and cultivating clonal strains. The number of cultivable protozoa was higher in the polluted soil; however, the polluted soil displayed an impoverished community, dominated by certain taxa, such as Acanthamoeba sp. We isolated a total of 31 protozoan strains to characterize them morphologically and by 18S rRNA...

  12. On-line DACC-HPLC analysis of polycyclic aromatic hydrocarbons in edible oils

    OpenAIRE

    Neđeral, Sandra; Pukec, Dragutin; Škevin, Dubravka; Kraljić, Klara; Obranović, Marko; Zrinjan, Petra

    2014-01-01

    In this work an HPLC method for determination of polycyclic aromatic hydrocarbons (PAH) in edible oils on a DACC (donor-acceptor complex chromatography) column coupled with an on-line HPLC system with fluorescent detection. Method was used to determine the content of individual PAHs in the refined sunflower oil, virgin olive oil, cold pressed pumpkin seed oil, dark sesame oil and pumpkin seed oil produced with roasting obtained from domestic market. Calibration and validation were conducted f...

  13. Determination of polycyclic aromatic hydrocarbons in water using an electrochemical DNA biosensor

    OpenAIRE

    R Manaffar; B Sehatnia; R Sabzi; Ehsani, A.

    2015-01-01

    Background and Objectives: Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental contaminants in aquatic environments. These contaminants are generated through oil spills, manufactory processes, and industrial wastes or naturally through the incomplete combustion of coal, oil, gas, and wood waste. Most of these compounds are noted as carcinogenic and mutagenic. Therefore, detection of these pollutants by a sensitive and inexpensive method is very important. Materials and Method...

  14. Exposure to Polycyclic Aromatic Hydrocarbons, Plasma Cytokines, and Heart Rate Variability

    OpenAIRE

    Binyao Yang; Qifei Deng; Wangzhen Zhang; Yingying Feng; Xiayun Dai; Wei Feng; Xiaosheng He; Suli Huang; Xiao Zhang; Xiaohai Li; Dafeng Lin; Meian He; Huan Guo; Huizhen Sun; Jing Yuan

    2016-01-01

    Epidemiological studies have suggested associations between polycyclic aromatic hydrocarbons (PAHs) and heart rate variability (HRV). However, the roles of plasma cytokines in these associations are limited. In discovery stage of this study, we used Human Cytokine Antibody Arrays to examine differences in the concentrations of 280 plasma cytokines between 8 coke-oven workers and 16 community residents. We identified 19 cytokines with significant different expression (fold change ≥2 or ≤−2, an...

  15. Estimation of individual dermal and respiratory uptake of polycyclic aromatic hydrocarbons in 12 coke oven workers.

    OpenAIRE

    VanRooij, J G; Bodelier-Bade, M M; Jongeneelen, F.J.

    1993-01-01

    Twelve workers from a coke plant in The Netherlands participated in an intensive skin monitoring programme combined with personal air sampling and biological monitoring during five consecutive eight hour workshifts. The purpose of the study was to make a quantitative assessment of both the dermal and respiratory intake of polycyclic aromatic hydrocarbons (PAHs). Pyrene was used as a marker compound for both dermal and respiratory exposure to PAHs. The biological measure for the internal expos...

  16. Biological monitoring of polycyclic aromatic hydrocarbon exposure in a highly polluted area of Poland.

    OpenAIRE

    Ovrebø, S; Fjeldstad, P E; Grzybowska, E; Kure, E H; Chorazy, M; Haugen, A

    1995-01-01

    Air pollution in Poland and particularly in Silesia is among the worst in Europe. Many coal mines and coke oven plants are located in this area, representing a major source of carcinogenic polycyclic aromatic hydrocarbons (PAHs). We quantitated the PAH exposure level in air samples using personal sampling devices, collected urine samples from the same individuals, and measured 1-hydroxypyrene with high performance liquid chromatography. Samples were collected twice, once in February and once ...

  17. DNA adducts as a measure of lung cancer risk in humans exposed to polycyclic aromatic hydrocarbons.

    OpenAIRE

    Kriek, E; van Schooten, F.J.; Hillebrand, M J; van Leeuwen, F E; Den Engelse, L; De Looff, A J; Dijkmans, A P

    1993-01-01

    Workers in the coking, foundry, and aluminum industry can be exposed to high concentrations of polycyclic aromatic hydrocarbons (PAHs) and are at increased risk for lung cancer, as are cigarette smokers. In recent years several studies on workers in the foundry and coking industries have been reported. In these studies, white blood cell(WBC) DNA was used for analysis of PAH-DNA adducts. Theoretically, DNA adduct formation is a more relevant biological parameter for assessing exposure risk tha...

  18. Lung cancer mortality and exposure to polycyclic aromatic hydrocarbons in British coke oven workers

    OpenAIRE

    Miller, Brian G.; Doust, Emma; Cherrie, John W.; Hurley, J Fintan

    2013-01-01

    Background Workers on coke oven plants may be exposed to potentially carcinogenic polycyclic aromatic hydrocarbons (PAHs), particularly during work on the ovens tops. Two cohorts, employees of National Smokeless Fuels (NSF) and the British Steel Corporation (BSC) totalling more than 6,600 British coke plant workers employed in 1967, had been followed up to mid-1987 for mortality. Previous analyses suggested an excess in lung cancer risk of around 25%, or less when compared with Social Class I...

  19. Pollution of Flooded Arable Soils with Heavy Metals and Polycyclic Aromatic Hydrocarbons (PAHs)

    OpenAIRE

    Ciesielczuk, Tomasz; Kusza, Grzegorz; Poluszyńska, Joanna; Kochanowska, Katarzyna

    2014-01-01

    Soils that are exposed to floodwaters because of shallow groundwater and periodical wetlands are, to a large extent, exposed to contamination by organic and inorganic compounds. These are mainly compounds that have drifted along with the inflow of heavily laden floodwater and are produced within the soil profile by the anaerobic transformation of organic matter. Heavy metals and polycyclic aromatic hydrocarbon (PAH) compounds are absorbed by the soil of the floodwaters, and moving in the soil...

  20. Structural Vector Description and Estimation of Normal Boiling Points for 66 Aromatic Hydrocarbons

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A molecular vector-type descriptor containing 6 variables is used to describe the structure of aromatic hydrocarbons (AHs) and relate to normal boiling points (bp) of AHs. The correlation coefficient (R) between the estimated bp and experimental bp is 0.9988 and the root mean square error (RMS) is 7.907° C for 66 AHs. The RMS obtained by cross-validation is 9.131° C, which implies the relationship model having good prediction ability.

  1. Tailoring ZSM-5 Zeolites for the Fast Pyrolysis of Biomass to Aromatic Hydrocarbons

    DEFF Research Database (Denmark)

    Hoff, Thomas C.; Gardner, David W.; Thilakaratne, Rajeeva;

    2016-01-01

    The production of aromatic hydrocarbons from cellulose by zeolite-catalyzed fast pyrolysis involves a complex reaction network sensitive to the zeolite structure, crystallinity, elemental composition, porosity, and acidity. The interplay of these parameters under the reaction conditions represent...... a major roadblock that has hampered significant improvement in catalyst design for over a decade. Here, we studied commercial and laboratory-synthesized ZSM-5 zeolites and combined data from 10 complementary characterization techniques in an attempt to identify parameters common to high...

  2. Detection and characterization of human serum antibodies to polycyclic aromatic hydrocarbon diol-epoxide DNA adducts.

    OpenAIRE

    Newman, M J; Light, B A; Weston, A; Tollurud, D; Clark, J L; Mann, D L; Blackmon, J P; Harris, C C

    1988-01-01

    The presence of serum antibodies to the diol-epoxide DNA adducts of representative polycyclic aromatic hydrocarbons (PAH), chrysene, benz[a]anthracene and benzo[a]pyrene, was determined by ELISA using serum samples obtained from normal healthy individuals. Antibodies that reacted against PAH adducted-DNA, but not against PAH-adducted protein, were found in the serum of approximately 40% of the test individuals. Specificity analysis of the antibodies demonstrated that serological cross-reactio...

  3. Polycyclic Aromatic Hydrocarbons Identification and Source Discrimination in Rural Soil of the Northern Persian Gulf Coast

    OpenAIRE

    Fatemeh Valizadeh-kakhki; Mohamad Pauzi Zakaria; Ahmad Zaharin Aris; Syaizwan Zahmir Zulkifli; Mehdi Mohammadi; Hasan Tajik

    2014-01-01

    Due to strategic situation of the Persian Gulf, identifying the petroleum pollution level and source is an important issue. Therefore, this paper enhanced fingerprinting method of applying biomarkers Polycyclic Aromatic Hydrocarbons (PAHs) in identifying source and distribution of oil spills of the exposed areas. 10 soil samples collected from the northern coasts of the Persian Gulf along three provinces in the south of Iran. PAH concentrations in the soil ranged from 42.76 to 5596.49 ng.g-1....

  4. Assessment of the bioavailability and phytotoxicity of sediment spiked with polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    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. PMID:26490893

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

    Energy Technology Data Exchange (ETDEWEB)

    Mulas, Giacomo; Casu, Silvia; Cecchi-Pestellini, Cesare [INAF-Osservatorio Astronomico di Cagliari, Strada n.54, Loc. Poggio dei Pini, I-09012 Capoterra (Italy); Zonca, Alberto, E-mail: gmulas@oa-cagliari.inaf.it, E-mail: silvia@oa-cagliari.inaf.it, E-mail: ccp@oa-cagliari.inaf.it, E-mail: azonca@oa-cagliari.inaf.it [Dipartimento di Fisica, Universita di Cagliari, Strada Prov.le Monserrato-Sestu Km 0.700, I-09042 Monserrato (Italy)

    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.

  6. Soil sealing degree as factor influencing urban soil contamination with polycyclic aromatic hydrocarbons (PAHs

    Directory of Open Access Journals (Sweden)

    Mendyk Łukasz

    2016-03-01

    Full Text Available The objective of the study was to determine role of soil sealing degree as the factor influencing soil contamination with polycyclic aromatic hydrocarbons (PAHs. The study area included four sampling sites located within the administrative boundaries of the Toruń city, Poland. Sampling procedure involved preparing soil pits representing three examples of soil sealing at each site: non-sealed soil as a control one (I and two degrees of soil sealing: semi-pervious surface (II and totally impervious surface (III. Together with basic properties defined with standard procedures (particle size distribution, pH, LOI, content of carbonates content of selected PAHs was determined by dichloromethane extraction using gas chromatography with mass spectrometric detection (GC-MS. Obtained results show that urban soils in the city of Toruń are contaminated with polycyclic aromatic hydrocarbons. Soil sealing degree has a strong influence on the soil contamination with polycyclic aromatic hydrocarbons. Totally sealed soils are better preserved from atmospheric pollution including PAHs. Combustion of grass/wood/coal was the main source of determined PAHs content in examined soils.

  7. Impact of molecular structure on secondary organic aerosol formation from aromatic hydrocarbon photooxidation under low-NOx conditions

    Science.gov (United States)

    Li, Lijie; Tang, Ping; Nakao, Shunsuke; Cocker, David R., III

    2016-08-01

    The molecular structure of volatile organic compounds determines their oxidation pathway, directly impacting secondary organic aerosol (SOA) formation. This study comprehensively investigates the impact of molecular structure on SOA formation from the photooxidation of 12 different eight- to nine-carbon aromatic hydrocarbons under low-NOx conditions. The effects of the alkyl substitute number, location, carbon chain length and branching structure on the photooxidation of aromatic hydrocarbons are demonstrated by analyzing SOA yield, chemical composition and physical properties. Aromatic hydrocarbons, categorized into five groups, show a yield order of ortho (o-xylene and o-ethyltoluene) > one substitute (ethylbenzene, propylbenzene and isopropylbenzene) > meta (m-xylene and m-ethyltoluene) > three substitute (trimethylbenzenes) > para (p-xylene and p-ethyltoluene). SOA yields of aromatic hydrocarbon photooxidation do not monotonically decrease when increasing alkyl substitute number. The ortho position promotes SOA formation while the para position suppresses aromatic oxidation and SOA formation. Observed SOA chemical composition and volatility confirm that higher yield is associated with further oxidation. SOA chemical composition also suggests that aromatic oxidation increases with increasing alkyl substitute chain length and branching structure. Further, carbon dilution conjecture developed by Li et al. (2016) is extended in this study to serve as a standard method to determine the extent of oxidation of an alkyl-substituted aromatic hydrocarbon.

  8. Draft Genome Sequence of Pseudomonas sp. Strain 10-1B, a Polycyclic Aromatic Hydrocarbon Degrader in Contaminated Soil

    OpenAIRE

    Bello-Akinosho, Maryam; Adeleke, Rasheed; Swanevelder, Dirk; Thantsha, Mapitsi

    2015-01-01

    Pseudomonas sp. strain 10-1B was isolated from artificially polluted soil after selective enrichment. Its draft genome consists of several predicted genes that are involved in the hydroxylation of the aromatic ring, which is the rate-limiting step in the biodegradation of polycyclic aromatic hydrocarbons.

  9. Aliphatic and aromatic hydrocarbons in particulate fallout of Alexandria, Egypt: Sources and implications

    Energy Technology Data Exchange (ETDEWEB)

    Aboul-Kassim, T.A.T.; Simoneit, B.R.T. [Oregon State Univ., Corvallis, OR (United States)

    1995-10-01

    Particulate fallout samples (PFS) were collected in Alexandria, and their aliphatic and aromatic hydrocarbon compositions were determined both quantitatively and qualitatively to characterize the homologous and biomarker compounds in terms of their original sources. The results show that all samples contain aliphatic hydrocarbons, including n-alkanes, UCM, isoprenoids, tri- and tetracyclic terpanes, hopanes, and steranes/diasteranes. The main source of these compounds is from petrochemical contamination with trace input of terrestrial higher plant wax. In addition, polycyclic aromatic hydrocarbons, which are considered to be combustion products from fossil fuels such as petroleum, are also widely distributed in all samples. Multivariate statistical analysis, including extended Q-mode factor analysis and linear programming technique, was performed in order to reduce the hydrocarbon data set into a meaningful number of end members (sources). This analysis indicates that there are two significant end members explaining 90% of the total variation among the samples and confirming petrochemical (79.6%), and thermogenic/pyrolytic (10.4%) sources in the PFS model. 65 refs., 7 figs., 4 tabs.

  10. Potential of non-ligninolytic fungi in bioremediation of chlorinated and polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Marco-Urrea, Ernest; García-Romera, Inmaculada; Aranda, Elisabet

    2015-12-25

    In previous decades, white-rot fungi as bioremediation agents have been the subjects of scientific research due to the potential use of their unspecific oxidative enzymes. However, some non-white-rot fungi, mainly belonging to the Ascomycota and Zygomycota phylum, have demonstrated their potential in the enzymatic transformation of environmental pollutants, thus overcoming some of the limitations observed in white-rot fungi with respect to growth in neutral pH, resistance to adverse conditions and the capacity to surpass autochthonous microorganisms. Despite their presence in so many soil and water environments, little information exists on the enzymatic mechanisms and degradation pathways involved in the transformation of hydrocarbons by these fungi. This review describes the bioremediation potential of non-ligninolytic fungi with respect to chlorinated hydrocarbons and polycyclic aromatic hydrocarbons (PAHs) and also shows known conversion pathways and the prospects for future research.

  11. Formation of Polycyclic Aromatic Hydrocarbons and Nitrogen Containing Polycyclic Aromatic Compounds in Titan's Atmosphere, the Interstellar Medium and Combustion

    Science.gov (United States)

    Landera, Alexander

    2013-12-01

    Several different mechanisms leading to the formation of (substituted) naphthalene and azanaphthalenes were examined using theoretical quantum chemical calculations. As a result, a series of novel synthetic routes to Polycyclic Aromatic Hydrocarbons (PAHs) and Nitrogen Containing Polycyclic Aromatic Compounds (N-PACs) have been proposed. On Earth, these aromatic compounds originate from incomplete combustion and are released into our environment, where they are known to be major pollutants, often with carcinogenic properties. In the atmosphere of a Saturn's moon Titan, these PAH and N-PACs are believed to play a critical role in organic haze formation, as well as acting as chemical precursors to biologically relevant molecules. The theoretical calculations were performed by employing the ab initio G3(MP2,CC)/B3LYP/6-311G** method to effectively probe the Potential Energy Surfaces (PES) relevant to the PAH and N-PAC formation. Following the construction of the PES, Rice-Ramsperger-Kassel-Markus (RRKM) theory was used to evaluate all unimolecular rate constants as a function of collision energy under single-collision conditions. Branching ratios were then evaluated by solving phenomenological rate expressions for the various product concentrations. The most viable pathways to PAH and N-PAC formation were found to be those where the initial attack by the ethynyl (C2H) or cyano (CN) radical toward a unsaturated hydrocarbon molecule led to the formation of an intermediate which could not effectively lose a hydrogen atom. It is not until ring cyclization has occurred, that hydrogen elimination leads to a closed shell product. By quenching the possibility of the initial hydrogen atom elimination, one of the most competitive processes preventing the PAH or N-PAC formation was avoided, and the PAH or N-PAC formation was allowed to proceed. It is concluded that these considerations should be taken into account when attempting to explore any other potential routes towards

  12. Compilation of a source profile database for hydrocarbon and OVOC emissions in China

    Science.gov (United States)

    Mo, Ziwei; Shao, Min; Lu, Sihua

    2016-10-01

    Source profiles are essential for quantifying the role of volatile organic compound (VOC) emissions in air pollution. This study compiled a database of VOC source profiles in China, with 75 species drawn from five major categories: transportation, solvent use, biomass burning, fossil fuel burning, and industrial processes. Source profiles were updated for diesel vehicles, biomass burning, and residential coal burning by measuring both hydrocarbons and oxygenated VOCs (OVOCs), while other source profiles were derived from the available literature. The OVOCs contributed 53.8% of total VOCs in the profiles of heavy - duty diesel vehicle exhaust and 12.4%-46.3% in biomass and residential coal burning, which indicated the importance of primary OVOCs emissions from combustion-related sources. Taking the national emission inventory from 2008 as an example, we established an approach for assigning source profiles to develop a speciation-specific VOC and OVOC emission inventory. The results showed that aromatics contributed 30% of the total 26 Tg VOCs, followed by alkanes (24%), alkenes (19%) and OVOCs (12%). Aromatics (7.9 Tg) were much higher than in previous results (1.1 Tg and 3.4 Tg), while OVOCs (3.1 Tg) were comparable with the 3.3 Tg and 4.3 Tg reported in studies using profiles from the US. The current emission inventories were built based on emission factors from non-methane hydrocarbon measurements, and therefore the proportions from OVOC emissions was neglected, leading to up to 30% underestimation of total VOC emissions. As a result, there is a need to deploy appropriate emission factors and source profiles that include OVOC measurements to reduce the uncertainty of estimated emissions and chemical reactivity potential.

  13. SPATIAL ANALYSIS OF THE POLYCYCLIC AROMATIC HYDROCARBON FEATURES SOUTHEAST OF THE ORION BAR

    Energy Technology Data Exchange (ETDEWEB)

    Boersma, C.; Rubin, R. H.; Allamandola, L. J., E-mail: Christiaan.Boersma@nasa.gov [NASA Ames Research Center, MS 245-6, Moffett Field, CA 94035-1000 (United States)

    2012-07-10

    Polycyclic aromatic hydrocarbon (PAH) and dust emission features between 10 and 37 {mu}m, observed with Spitzer at 11 positions southeast of the Bright Bar (BB) in Orion, are analyzed and connected to atomic and H{sub 2} lines reported earlier. Variations at these positions indicate changes in local conditions and materials sampled. The major findings are: (1) PAH erosion and destruction are important from the BB out to about 5'. (2) The ionized PAH fraction, inferred from the 11.0 {mu}m PAH band, increases from the BB out to 6.'5. This counterintuitive behavior is linked to PAH dehydrogenation. (3) The '11.2' {mu}m PAH band profile shifts from class A{sub 11.2} to A(B){sub 11.2} between 9' and 10', indicating these lines-of-sight probe a different environment, likely shielded molecular cloud material. (4) The different spatial behavior of the PAH bands and the 10-15 {mu}m plateau supports the view that the plateau originates in a separate carrier. (5) The fullerene/PAH band strength ratio decreases out to about 7', increases between 9' and 10' and drops at 12'. The first region is where PAHs are dehydrogenated and eroded whereas the second, shielded zone, is where the '11.2' {mu}m profile shifts and PAH erosion is unlikely. This suggests fullerenes are intimately mixed with PAHs in shielded regions. Taken together, the observations suggest three different regimes are sampled: (1) the H II region-photodissociation region (PDR) interface directly southeast of the BB, (2) shielded molecular cloud material farther out, and (3) the H II region-PDR interface seen limb brightened at the outermost position.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-07-20

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

  15. Determination of polycyclic aromatic hydrocarbons in urban street dust: implications for human health.

    Science.gov (United States)

    Lorenzi, Damien; Entwistle, Jane A; Cave, Mark; Dean, John R

    2011-05-01

    The determination of sixteen polycyclic aromatic hydrocarbons in urban street dust has been done. Samples were collected from 12 sampling locations in a city centre location (Newcastle upon Tyne, north east England) and extracted using in situ pressurised fluid extraction followed by gas chromatography mass spectrometry. From the results it was possible to identify three groups, with respect to PAH concentration, with PAH contents ranging between 0.6-2.3 mg kg(-1), 15.6-22.5 mg kg(-1) and 36.1-46.0 mg kg(-1). The total PAH content of samples from these sampling sites has been compared to 22 urban locations around the world; comparable levels were found in these samples compared to the other cities around the world. The potential source of PAHs has been investigated by investigating the proportion of pyrogenic and petrogenic material in urban street dust using specific individual PAH ratios. The results indicate that the PAH content of urban street dust from the chosen sites are more likely to be due to pyrogenic sources i.e. vehicle exhaust emissions. The particle size fractions (PAHs in three selected sampling sites was investigated. In two of the selected sites the PAH content was independent of particle size whereas in sampling site 10 elevated PAH levels are noted in the PAHs was assessed in terms of a mean daily intake (based on an ingestion rate of 100 mg d(-1)). It was found that all 4-6 membered ring PAHs had concentrations in excess of the mean daily intake thereby reflecting a potential health risk, particularly in the smallest size particle fractions.

  16. Polycyclic aromatic hydrocarbons in urban street dust and surface soil: comparisons of concentration, profile, and source.

    Science.gov (United States)

    Wang, De-Gao; Yang, Meng; Jia, Hong-Liang; Zhou, Lei; Li, Yi-Fan

    2009-02-01

    Street dust and surface soil samples in urban areas of Dalian, a coastal city in Liaoning Province, China, were collected and analyzed for 25 polycyclic aromatic hydrocarbons (PAHs). The concentrations, distribution, and sources of PAHs in dust and soil were determined. The concentrations of total PAHs in street dust ranged between 1890 and 17,070 ng/g (dry weight), with an average of 7460 ng/g, whereas the concentrations of total PAHs in surface soil varied greatly, from 650 to 28,900 ng/g, with a mean value of 6440 ng/g. Statistical paired t-test confirmed that total PAH concentrations have no significant difference between street dust and surface soil. Mean PAH concentrations in two type samples were much higher at industrial sites than at business/residential or garden sites. PAHs were dominated by higher molecular weight PAH (4- to 6-ring) homologues, which accounted for about 73% and 72% of total PAHs in street dust and surface soil, respectively. Principal component analysis was used in source apportionment of PAHs in dust and soil. Pyrogenic and petrogenic sources contributed 70% and 22.4% of total PAHs in street dusts, and fossil fuel (coal and petroleum) and biomass combustion accounted for 64.4% and 5.6% of total PAHs in pyrogenic sources, respectively. In surface soil, total PAHs were dominated by pyrogenic sources. The diagnostic ratios of benz[a]anthracene/chrysene confirmed that PAHs in street dust and surface soil of a Dalian urban zone might come mostly from the emission of local sources.

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

    Science.gov (United States)

    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. PMID:17579898

  18. Laser Induced Fluorescence Spectroscopy of Neutral and Ionized Polycyclic Aromatic Hydrocarbons in a Cosmic Simulation Chamber

    Science.gov (United States)

    Bejaoui, Salma; Salama, Farid

    2015-08-01

    Polycyclic aromatic hydrocarbon (PAH) molecules are considered the best carriers to account for the ubiquitous infrared emission bands. PAHs have also been proposed as candidates to explain the diffuse interstellar bands (DIBs), a series of absorption features seen on the interstellar extinction curve and are plausible carriers for the extended red emission (ERE), a photoluminescent process associated with a wide variety of interstellar environments. Extensive efforts have been devoted over the past two decades to characterize the physical and chemical properties of PAH molecules and ions in space. Absorption spectra of PAH molecules and ions trapped in solid matrices have been compared to the DIBs [1, 2]. Absorption spectra of several cold, isolated gas-phase PAHs have also been measured under experimental conditions that mimic the interstellar conditions [see 3 for a review]. The purpose of this study is to provide a new dimension to the existing spectroscopic database of neutral and single ionized PAHs that is largely based on absorption spectra by adding emission spectroscopy data. The measurements are based on the laser-induced fluorescence (LIF) technique [4] and are performed with the Pulsed Discharge Nozzle (PDN) of the COSmIC laboratory facility at NASA Ames laboratory. The PDN generates plasma in a free supersonic jet expansion to simulate the physical and the chemical conditions in interstellar environments. We focus, here, on the fluorescence spectra of large neutral PAHs and their cations where there is a lack of fluorescence spectroscopy data. The astronomical implications of the data (e.g., ERE) are examinedReferences[1] F. Salama, E. Bakes, L.J. Allamandola, A.G.G.M. Tielens, Astrophys. J., 458 (1996) p.621[2] F. Salama, The ISO Revolution, EDP Sciences, Les Ulis, France (1999) p.65[3] Salama F., In Organic Matter in Space, IAU Symposium 251, Kwok & Sandford Eds.Cambridge University Press,4, S251,(2008), p. 357 (2008) and references therein.[4

  19. Measurements and source apportionment of particle-associated polycyclic aromatic hydrocarbons in ambient air in Riyadh, Saudi Arabia

    Science.gov (United States)

    Bian, Qijing; Alharbi, Badr; Collett, Jeffrey; Kreidenweis, Sonia; Pasha, Mohammad J.

    2016-07-01

    Ambient air samples were obtained in Riyadh, the capital and largest city of Saudi Arabia, during two measurement campaigns spanning September 2011 to September 2012. Sixteen particle-phase polycyclic aromatic hydrocarbons (PAH) were quantified in 167 samples. Pyrene and fluoranthene were the most abundant PAH, with average of 3.37 ± 14.01 ng m-3 and 8.00 ± 44.09 ng m-3, respectively. A dominant contribution from low molecular weight (LMW) PAH (MW oil combustion emissions dominated total PAH concentrations, accounting for on average 96%, likely due to widespread use of oil fuels in energy production (power plants and industries). Our results demonstrate the significant influence of petroleum product production and consumption on particulate-phase PAH concentrations in Riyadh, but also point to the importance of traffic and solid fuel burning, including coke burning and seasonal biomass burning, especially as they contribute to the ambient levels of HMW PAH.

  20. Application of the cubic-plus-association (CPA) equation of state to complex mixtures with aromatic hydrocarbons

    DEFF Research Database (Denmark)

    Folas, Georgios; Kontogeorgis, Georgios; Michelsen, Michael Locht;

    2006-01-01

    The cubic-plus-association (CPA) equation of state is applied to phase equilibria of mixtures containing alcohols, glycols, water, and aromatic or olefinic hydrocarbons. Previously, CPA has been successfully used for mixtures containing various associating compounds (alcohols, glycols, amines......, organic acids, and water) and aliphatic hydrocarbons. We show in this work that the model can be satisfactorily extended to complex vapor-liquid-liquid equilibria with aromatic or olefinic hydrocarbons. The solvation between aromatics/olefinics and polar compounds is accounted for. This is particularly...... important for mixtures containing water and glycols, but less so for mixtures with alcohols. For water/hydrocarbons, a single binary interaction parameter which accounts for the solvation is fitted to the experimental liquid-liquid equilibria (LLE) data. The interaction parameter of the physical term...

  1. Biodegradation Of Polycyclic Aromatic Hydrocarbons In Petroleum Oil Contaminating The Environment

    International Nuclear Information System (INIS)

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants in urban atmospheres (Chen et al., 2013). PAHs enter the environment via incomplete combustion of fossil fuels and accidental leakage of petroleum products, and as components of products such as creosote (Muckian et al., 2009). Due to PAHs carcinogenic activity, they have been included in the European Union (EU) and the Environmental Protection Agency (EPA) priority pollutant lists. Human exposure to PAHs occurs in three ways, inhalation, dermal contact and consumption of contaminated foods, which account for 88-98% of such contamination; in other words, diet is the major source of human exposure to these contaminants (Rey-Salgueiro et al., 2008). Both the World Health Organization and the UK Expert Panel on Air Quality Standards (EPAQS) have considered benzo(a)pyrene (BaP) as a marker of the carcinogenic potency of the polycyclic aromatic hydrocarbons (PAH) mixture (Delgado-Saborit et al., 2011). Polycyclic aromatic and heavier aliphatic hydrocarbons, which have a stable recalcitrant molecular structure, exhibit high hydrophobicity and low aqueous solubility, are not readily removed from soil through leaching and volatilization (Brassington et al., 2007). The hydrophobicity of PAHs limits desorption to the aqueous phase (Donlon et al., 2002). Six main ways of dissipation, i.e. disappearance, are recognized in the environment: volatilization, photooxidation, Aim of the Work chemical oxidation, sorption, leaching and biodegradation. Microbial degradation is considered to be the main process involved in the dissipation of PAH (Yuan et al., 2002). Thus, more and more research interests are turning to the biodegradation of PAHs. Some microorganisms can utilize PAHs as a source of carbon and energy so that PAHs can be degraded to carbon dioxide and water, or transformed to other nontoxic or low-toxic substances (Perelo, 2010). Compared with other physical and chemical methods such as combustion

  2. C-H and N-H bond dissociation energies of small aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Barckholtz, C.; Barckholtz, T.A.; Hadad, C.M.

    1999-01-27

    A survey of computational methods was undertaken to calculate the homolytic bond dissociation energies (BDEs) of the C-H and N-H bonds in monocyclic aromatic molecules that are representative of the functionalities present in coal. These include six-membered rings (benzene, pyridine, pyridazine, pyrimidine, pyrazine) and five-membered rings (furan, thiophene, pyrrole, oxazole). By comparison of the calculated C-H BDEs with the available experimental values for these aromatic molecules, the B3LYP/6-31G(d) level of theory was selected to calculate the BDEs of polycyclic aromatic hydrocarbons (PAHs), including carbonaceous PAHs (naphthalene, anthracene, pyrene, coronene) and heteroatomic PAHs (benzofuran, benzothiophene, indole, benzoxazole, quinoline, isoquinoline, dibenzofuran, carbazole). The cleavage of a C-H or a N-H bond generates a {sigma} radical that is, in general, localized at the site from which the hydrogen atom was removed. However, delocalization of the unpaired electron results in {approximately} 7 kcal {center{underscore}dot} mol{sup {minus}1} stabilization of the radical with respect to the formation of phenyl when the C-H bond is adjacent to a nitrogen atom in the azabenzenes. Radicals from five-membered rings are {approximately} 6 kcal {center{underscore}dot} mol{sup {minus}1} less stable than those formed from six-membered rings due to both localization of the spin density and geometric factors. The location of the heteroatoms in the aromatic ring affects the C-H bond strengths more significantly than does the size of the aromatic network. Therefore, in general, the monocyclic aromatic molecules can be used to predict the C-H BDE of the large PAHs within 1 kcal {center{underscore}dot} mol{sup {minus}1}.

  3. Distribution and Geochemical Implication of Aromatic Hydrocarbons across the Meishan Permian-Triassic Boundary

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Aromatic compounds extracted from sedimentary rocks can reflect environmental conditions, organic sources and maturity. The aromatics, identified in association with mass extinction in particular, would provide a signature assisting our understanding of the causes of the biotic crisis. Aromatic hydrocarbons were fractionated from the total lipid extracts of 37 samples taken from the Permian Triassic boundary (beds 23 to 34) of section B at Meishan(煤山),Zhejiang(浙江)Province in South China. These aromatics were analyzed by using gas chromatography-mass spectrometry (GC-MS). Main compounds identified include naphthalene, phenanthrenes, fluorene, dibenzothiophene, dibenzofuran, fluoranthene, pyrene and some of their methyl homologues. The indices of methyl phenanthrene distribution fraction indicate the comparable maturity (within the oil window, 0.7% - 1.0% of the mean vitrinite reflectance) of the organic matter throughout the whole profile analyzed. The ratio of dibenzothiophene to phenanthrene (DBT/PHN) varies generally at a comparable pace with lithology. Significantly,a gradual decrease of this ratio was observed within bed 24 limestone, which is probably due to the variation of sedimentary environment. This change is in line with the drop in the carbon isotope composition of carbonate, the loss of the Changhsingian reef ecosystem, and the decrease of cyanobacteria abundance within the bacteria population. The coincidence of these records suggests a close relation between the biotic crisis and marine environmental conditions, and these records clearly show the onset of the biotic crisis prior to event bed 25.

  4. Understanding the Reactivity of Planar Polycyclic Aromatic Hydrocarbons: Towards the Graphene Limit.

    Science.gov (United States)

    García-Rodeja, Yago; Solà, Miquel; Fernández, Israel

    2016-07-18

    The Diels-Alder reactivity of maleic anhydride towards the bay regions of planar polycyclic aromatic hydrocarbons was explored computationally in the DFT framework. The process becomes more and more exothermic and the associated activation barriers become lower and lower when the size of the system increases. This enhanced reactivity follows an exponential behavior that reaches its maximum for systems having 18-20 benzenoid rings in their structures. This peculiar behavior was analyzed in detail by using the activation strain model of reactivity in combination with energy decomposition analysis. The influence of the change in the aromaticity of the polycyclic compound during the process on the respective activation barriers was also studied. PMID:27304921

  5. Polycyclic aromatic hydrocarbon composition in soils and sediments of high altitude lakes

    Energy Technology Data Exchange (ETDEWEB)

    Grimalt, Joan O.; Drooge, Barend L. van; Ribes, Alejandra; Fernandez, Pilar; Appleby, Peter

    2004-09-01

    Polycyclic aromatic hydrocarbons (PAH) in lake sediments and nearby soils of two European high mountain regions, Pyrenees and Tatra, have been studied. Similar mixtures of parent PAH were observed in all cases, indicating predominance of airborne transported combustion products. Nevertheless, the composition of these atmospherically long-range transported PAH was better preserved in the superficial layers of soils than sediments. This difference points to significant PAH degradation process, e.g. during lake water column transport, before accumulation in the latter. Post-depositional transformation was also different in both types of environmental compartments. Thus, lake sediments exhibit higher preservation of the more labile PAH involving lower degree of post-depositional oxidation. However, they also show the formation of major amounts of perylene by diagenetic transformation in the deep sections. This compound is not formed in soils where downcore enrichments of phenanthrene are observed, probably as a consequence of diagenetic aromatization of diterpenoids.

  6. Global modeling of secondary organic aerosol formation from aromatic hydrocarbons: high- vs low-yield pathways

    Directory of Open Access Journals (Sweden)

    D. K. Henze

    2007-10-01

    Full Text Available Formation of SOA from the aromatic species toluene, xylene, and, for the first time, benzene, is added to a global chemical transport model. A simple mechanism is presented that accounts for competition between low and high-yield pathways of SOA formation, wherein secondary gas-phase products react further with either nitrogen oxide (NO or hydroperoxy radical (HO2 to yield semi- or non-volatile products, respectively. Aromatic species yield more SOA when they react with OH in regions where the [NO]/[HO2] ratios are lower. The SOA yield thus depends upon the distribution of aromatic emissions, with biomass burning emissions being in areas with lower [NO]/[HO2] ratios, and the reactivity of the aromatic with respect to OH, as a lower initial reactivity allows transport away from industrial source regions, where [NO]/[HO2] ratios are higher, to more remote regions, where this ratio is lower and, hence, the ultimate yield of SOA is higher. As a result, benzene is estimated to be the most important aromatic species with regards to formation of SOA, with a total production nearly equal that of toluene and xylene combined. In total, while only 39% percent of the aromatic species react via the low-NOx pathway, 72% of the aromatic SOA is formed via this mechanism. Predicted SOA concentrations from aromatics in the Eastern United States and Eastern Europe are actually largest during the summer, when the [NO]/[HO2] ratio is lower. Global production of SOA from aromatic sources is estimated at 3.5 Tg/yr, resulting in a global burden of 0.08 Tg, twice as large as previous estimates. The contribution of these largely anthropogenic sources to global SOA is still small relative to biogenic sources, which are estimated to comprise 90% of the global SOA burden, about half of which comes from isoprene. Compared to recent observations, it would appear there are additional pathways beyond those

  7. Magnetic ionic liquids as non-conventional extraction solvents for the determination of polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    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. PMID:27506350

  8. Occupational exposure to polycyclic aromatic hydrocarbons in airborne particulate matter: validation and application of a gas chromatography-mass spectrometry analytical method.

    Science.gov (United States)

    Fioretti, Marzia; Catrambone, Tamara; Gordiani, Andrea; Cabella, Renato

    2010-12-01

    This study concerns the validation of an analytical method for the measurement of occupational exposure to trace levels of polycyclic aromatic hydrocarbons (PAHs) in airborne particulate matter (APM). Personal exposure to selected PAHs of five workers occupationally exposed to urban pollution in Rome, Italy, was evaluated. The samples were collected over 10 days evenly distributed during winter and summer of 2008. Polycyclic aromatic hydrocarbons were collected by a sampling pump and trapped in polytetrafluoroethylene filters; ultrasonic extraction was applied to extract PAH species from the matrix with toluene, and the concentrated extract was quantitatively analyzed by GC/MS. The analytical method was optimized and validated using a standard reference material of urban dust (SRM 1649a). Detection limits ranged from 0.8 ng per sample for indeno [1,2,3-cd] pyrene to 20.4 ng for sample for anthracene. Experimental results of the 50 personal samples collected showed that phenanthrene was the predominant polycyclic aromatic hydrocarbon [95% CI (32.42-41.13 ng m(-3))]; the highest benzo[a]pyrene concentration was 2.58 ng m(-3), approximately 2-fold higher than European annual target values (1 ng m(-3)). Seasonal variations of personal exposure to selected PAHs suggested higher emissions and reduced atmospheric reactivity of PAH compounds in winter. The analytical method was a suitable procedure for the determination of 13 of the 16 priority PAHs in APM personal samples and can be considered a useful tool to evaluate occupational exposure to low PAH levels.

  9. Removal of polycyclic aromatic hydrocarbons from aqueous solution using plant residue materials as a biosorbent

    Energy Technology Data Exchange (ETDEWEB)

    Chen Baoliang, E-mail: blchen@zju.edu.cn [Department of Environmental Science, Zhejiang University, Hangzhou, Zhejiang 310028 (China); Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Zhejiang University, Hangzhou, Zhejiang 310028 (China); Yuan Miaoxin; Liu Hao [Department of Environmental Science, Zhejiang University, Hangzhou, Zhejiang 310028 (China); Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Zhejiang University, Hangzhou, Zhejiang 310028 (China)

    2011-04-15

    Graphical abstract: The structure-effect relationship provides a reference to select and modify plant residues as a biosorbent with high efficiency to tackle organic pollutants. Research highlights: {yields} Polycyclic aromatic hydrocarbons are effectively removed by plant residues. {yields} Biosorption mechanism of plant residues to abate PAHs is a partitioning process. {yields} Partition coefficients are negatively related with sugar contents of biosorbent. {yields} The aromatic component and K{sub ow} exhibit positive effects on biosorption. {yields} The structure-effect relationship guides plant residue using as a biosorbent. - Abstract: To elucidate biosorption mechanism and removal efficiency of plant residues as a biosorbent to abate polycyclic aromatic hydrocarbons (PAHs) in wastewater, sorption of PAHs onto wood chips (WC), ryegrass roots (RR), orange peels (OP), bamboo leaves (BL), and pine needles (PN) were investigated. The structural characterization of the biosorbents was analyzed by elemental composition, BET-N{sub 2} surface area, and Fourier transform infrared spectroscopy. PAHs sorption to the selected biosorbents were compared and correlated with their structures. Biosorption isotherms fit well with Freundlich equation and the mechanism was dominated by partition process. The magnitude of phenanthrene partition coefficients (K{sub d}) followed the order of PN > BL > OP > RR > WC, ranged from 2484 {+-} 24.24 to 5306 {+-} 92.49 L/kg. Except the WC sample, the K{sub d} values were negatively correlated with sugar content, polar index [(N + O)/C] of the biosorbents, while the aromatic component exhibited positive effects. For a given biosorbent of bamboo leaves, the carbon-normalized partition coefficients (K{sub oc}) were linearly correlated with octanol-water partition coefficients (K{sub ow}) of PAHs, i.e., log K{sub oc} = 1.16 log K{sub ow} - 1.21. The structure-effect relationship provides a reference to select and modify plant residues as a

  10. Assessment of concentration, bioaccumulation and sources of polycyclic aromatic hydrocarbons in zooplankton of Chabahar Bay.

    Science.gov (United States)

    Ziyaadini, Morteza; Mehdinia, Ali; Khaleghi, Leila; Nassiri, Mahmoud

    2016-06-15

    The amounts and sources of polycyclic aromatic hydrocarbons (PAHs) and their bioaccumulation factors (BAFs) in the zooplankton community of Chabahar Bay were investigated. The highest amounts of total PAHs (tPAHs) in the water and zooplankton samples were 62.2ngL(-1) and 1478.6ngg(-1) dry weights, in near the Shahid Beheshti Port and desalination, respectively. The greatest amount of BAF (51,780) was obtained in the entry of Bay, and it was related to the phenanthrene accumulation. Using molecular ratio, the results showed that the major input source of PAH compounds in zooplankton of Chabahar Bay was pyrolytic (fuel) source. PMID:26944700

  11. Occurrence and sources of particulate nitro-polycyclic aromatic hydrocarbons in ambient air in Denmark

    DEFF Research Database (Denmark)

    Feilberg, A.; Poulsen, M.W.B.; Nielsen, T.;

    2001-01-01

    The occurrence of selected nitro-polycyclic aromatic hydrocarbons (nitro-PAHs) associated with atmospheric particulate matter has been investigated at an urban site and at a semi-rural site. For this purpose an analysis method based on gas chromatography and tandem ion trap mass spectrometry has...... been developed and applied. The nitro-PAK levels have been compared with levels of other air pollutants including unsubstituted PAHs, inorganic gases and particulate matter, as well as with meteorological parameters. Correlations and concentration ratios suggest that the dominant source of 9...

  12. Exposures to Particulate Matter and Polycyclic Aromatic Hydrocarbons and Oxidative Stress in Schoolchildren

    OpenAIRE

    Bae, Sanghyuk; Pan, Xiao-Chuan; Kim, Su-Young; Park, Kwangsik; Kim, Yoon-Hee; Kim, Ho; Hong, Yun-Chul

    2009-01-01

    Background Air pollution is known to contribute to respiratory and cardiovascular mortality and morbidity. Oxidative stress has been suggested as one of the main mechanisms for these effects on health. Objective The aim of this study was to analyze the effects of exposure to particulate matter (PM) with aerodynamic diameters ≤ 10 μm (PM10) and ≤ 2.5 μm (PM2.5) and polycyclic aromatic hydrocarbons (PAHs) on urinary malondialdehyde (MDA) levels in schoolchildren. Methods The study population co...

  13. Polycyclic aromatic hydrocarbons fingerprints in the Pichavaram mangrove-estuarine sediments, southeastern India

    OpenAIRE

    Ranjan, Rajesh Kumar; Routh, Joyanto; Ramanathan, A.L.; Klump, J. Val

    2012-01-01

    The sources and historical deposition of 16 polycyclic aromatic hydrocarbons (PAHs) were investigated in dated sediment cores from the Pichavaram mangrove–estuarine complex. The ΣPAH flux in mangrove and estuarine sediments was 0.064 ± 0.031 μg/cm2/yr and 0.043 ± 0.020 μg/cm2/yr, respectively. The PAH flux in sediments increased up-core, coinciding with rapid urbanization since the 1970s. The flux showed a decrease in recent years (since 1990), coinciding with less riverine discharge, and per...

  14. Structures and electronic properties of thin-films of polycyclic aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Natsume, Yutaka [Asahi-Kasei Corporation, 2-1 Samejima, Fuji, Shizuoka (Japan)], E-mail: natsume.yc@om.asahi-kasei.co.jp; Minakata, Takashi; Aoyagi, Takeshi [Asahi-Kasei Corporation, 2-1 Samejima, Fuji, Shizuoka (Japan)

    2009-03-02

    We report the fabrication and characterization of organic thin-film transistors (TFTs) using several polycyclic aromatic hydrocarbons (PAHs). Pentacene, ovalene, dibenzocoronene and hexabenzocoronene were deposited as organic semiconductors on silicon wafers with gold electrodes as the bottom-contact configuration of the TFTs. The pentacene TFT showed the highest field-effect mobility of more than 0.1 cm{sup 2}/Vs in comparison with the other PAHs. The results clarified that the high field-effect mobility of the pentacene thin film is due to large grain size and intrinsic electronic properties.

  15. Polycyclic aromatic hydrocarbons and the Oak Ridge National Laboratory's experimental coal program: minimizing the hazards

    Energy Technology Data Exchange (ETDEWEB)

    Forrester, R.C. III; Cochran, H.D.; Bolton, N.E.

    1977-01-01

    Many processing techniques for the liquefaction or gasification of coal are being developed at the Oak Ridge National Laboratory and elsewhere. Although different in many other respects, all coal conversion processes produce a liquid effluent comprising a complex mixture of hydrocarbons. Such mixtures invariably contain significant amounts of polycyclic, aromatic compounds, some of which are known to be highly active carcinogens. The underlying philosophy that has been adopted for the protection of personnel involved in experimental coal processing operations is defined, and procedures that have been instituted to govern the conduct of such experimental work and handling of associated coal-derived liquids are detailed.

  16. Polycyclic aromatic hydrocarbons (PAH) and polychlorinated biphenyls (PCB) in urban soils of Greater London, UK

    OpenAIRE

    Vane, Christopher H.; Kim, Alexander W.; Beriro, Darren J.; Cave, Mark R.; Knights, Katherine; Moss-Hayes, Vicky; Nathanail, Paul C.

    2014-01-01

    Surface soils from a 19 km2 area in east London, UK were analysed for polycyclic aromatic hydrocarbons (PAH) and polychlorinated biphenyls (PCB) (n = 76). ∑16 PAH ranged from 4 to 67 mg/kg (mean, 18 mg/kg) and ∑50 PAH ranged from 6 to 88 mg/kg (mean, 25 mg/kg). ∑7 PCB ranged from 1 to 750 μg/kg (mean, 22 μg/kg) and ∑tri-hepta PCB ranged 9 to 2600 μg/kg (mean, 120 μg/kg). Compared to other international cities concentrations were similar for PAH but higher for PCB. Normal background concentrat...

  17. Contamination of soils in the urbanized areas of Belarus with polycyclic aromatic hydrocarbons

    Science.gov (United States)

    Kukharchyk, T. I.; Khomich, V. S.; Kakareka, S. V.; Kurman, P. V.; Kozyrenko, M. I.

    2013-02-01

    The content of polycyclic aromatic hydrocarbons (PAHs) in the soils of urbanized areas, including the impact zones of Belarus, were studied. The concentrations of 16 PAHs in the soils were determined for individual and high-rise building zones, forests, and forest parks of Belarus. The levels of the PAH accumulation in the soils of different industrial enterprises and boiler stations were analyzed. Possible sources of soil contamination with PAHs were considered, and the structure of the PAHs in the soils was shown. The levels of the soil contamination were determined from the regulated parameters for individual compounds and the sum of 16 PAHs.

  18. Aromatic hydrocarbon pathology in fish following a large spill into the Nemadji River, Wisconsin, USA

    Science.gov (United States)

    Caldwell, C.A.

    1997-01-01

    On June 30, 1992, a train accident resulted in a rail car releasing 114,000 L of a complex mixture of aromatic hydrocarbons into the Nemadji River, a tributary of Lake Superior near Superior, Wisconsin (Table 1). Although the majority of the spilled material evaporated, damage to aquatic life was extensive. Several thousand fishes were killed and an inestimable number were exposed to low concentrations (kidney were examined for histopathology. Blood was collected to determine the severity of liver damage reflected by the presence of the serum enzymes (aspartate aminotransferase, alanine aminotransferase, and d - glutamyl transferase).

  19. A review on polycyclic aromatic hydrocarbons: Source, environmental impact, effect on human health and

    Directory of Open Access Journals (Sweden)

    Hussein I. Abdel-Shafy

    2016-03-01

    The aim of this review is to discuss PAHs impact on the environmental and the magnitude of the human health risks posed by such substances. They also contain important information on concentrations, burdens and fate of polycyclic aromatic hydrocarbons (PAHs in the atmosphere. The main anthropogenic sources of PAHs and their effect on the concentrations of these compounds in air are discussed. The fate of PAHs in the air, their persistence and the main mechanisms of their losses are presented. Health hazards associated with PAH air pollution are stressed.

  20. Humoral immunosuppression in men exposed to polycyclic aromatic hydrocarbons and related carcinogens in polluted environments.

    OpenAIRE

    Szczeklik, A; Szczeklik, J; Galuszka, Z; Musial, J; Kolarzyk, E; Targosz, D

    1994-01-01

    We evaluated humoral immunity by measuring IgG, IgA, IgM, and IgE concentrations in 274 male workers in an iron foundry in Cracow, Poland. There were two groups: 199 coke oven workers and 76 cold-rolling mill workers. The groups were similar with respect to age, length of work (average 15 years), and smoking habits. Exposure to polycyclic aromatic hydrocarbons (PAHs), assessed by personal and area monitoring, ranged from 0.2 to 50 micrograms/m3 benzo[a]pyrene in coke plant workers and was of ...

  1. Characterization and source apportionment of polycyclic aromatic hydrocarbons (PAHs) in Sediments from the Bohai Sea, China

    Science.gov (United States)

    Liu, Jihua; Hu, Ningjing; Shi, Xuefa

    2015-04-01

    Characterization and source apportionment of polycyclic aromatic hydrocarbons (PAHs) in Sediments from the Bohai Sea, China Liu Jihua, Hu Ningjing, Shi Xuefa First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, China Polycyclic aromatic hydrocarbons (PAHs) are a class of ubiquitous organic contaminants in the environment. Indeed, 16 PAH compounds have been listed as priority pollutants by the United States Environmental Protection Agency and the European Union because of their potential toxicity to humans and ecosystems. As POPs are released or escape into the environment, their global accumulation in marine sediments generates a complex balance between inputs and outputs. Furthermore, PAHs in coastal sediments can serve as effective tracers of materials transport from land-to-sea (Fang et al., 2009). Hence, investigations of PAHs in sediments can provide useful information for further understanding of environmental processes and material transport. In this study, sixteen polycyclic aromatic hydrocarbons (PAHs) were extracted from a total of 112 surface sediment samples collected across the entire territory of the Bohai Sea. The detectable concentrations of PAHs ranged from 97.2 to 300.7 ng/g across all samples, indicating low contamination levels of PAHs compared with reported values for other coastal sediments in China and developed countries. The highest concentrations were found within three belts in the vicinity of Luan River Estuary-Qinhuangdao Harbor, the Cao River Estuary-Bohai Sea Center, and north of the Yellow River Estuary. The distribution patterns of PAHs and source identification implied that PAH contamination in the Bohai Sea mainly originates from offshore oil exploration, sewage discharge from rivers and shipping activities. Further Principal components analysis (PCA)/multivariate linear regression (MLR) analysis suggested that the contributions of spilled oil products (petrogenic), coal combustion and traffic

  2. Oxygen-containing polycyclic aromatic hydrocarbons (OPAHs) and their parent-PAHs in soil

    OpenAIRE

    Bandowe, Benjamin Acham Musa

    2010-01-01

    In spite of the higher toxicity of oxygen-containing polycyclic aromatic hydrocarbons (OPAHs) than of their parent-PAHs, there are only a few studies of the concentrations, composition pattern, sources and fate of OPAHs in soil, the presumably major environmental sink of OPAHs. This is related to the fact that there are only few available methods to measure OPAHs together with PAHs in soil. rnThe objectives of my thesis were to (i) develop a GC/MS-based method to measure OPAHs and their paren...

  3. Distribution and Risk Assessment of Polycyclic Aromatic Hydrocarbons in Vegetables Grown in Pakistan

    OpenAIRE

    Ashraf, Mohammad W.; Syed Iqleem H. Taqvi; Solangi, Amber R.; Qureshi, Umair A.

    2013-01-01

    Distribution and risk assessment of eight priority polycyclic aromatic hydrocarbons (PAHs) contents have been examined in different varieties of vegetables grown in Pakistan. The results showed that the total PAH contents were higher for root vegetables like potato and carrot (~13 μg/kg) and relatively lower for turnip (10.9 μg/kg), respectively while for the fruit vegetables, all the peels were found to be more contaminated than cores. The ratio of total PAH concentrations in peels with resp...

  4. Dermal uptake of polycyclic aromatic hydrocarbons after hairwash with coal-tar shampoo

    Energy Technology Data Exchange (ETDEWEB)

    Schooten, F.-J. van; Moonen, E.J.C.; Rhijnsburger, E.; Agen, B. van; Thijssen, H.H.W.; Kleinjans, J.C.S. [University of Limburg, Maastricht (Netherlands). Dept. of Health Risk Analysis and Toxicology

    1994-11-26

    Describes an experiment to assess the dermal uptake of polycyclic aromatic hydrocarbons (PAHs) after hairwashing with coal tar antidandruff shampoo. The urinary excretion of 1-hydroxypyrene (1-OH-P), a PAH metabolile was used to assess internal dose of PAH. A single use of coal tar shampoo resulted in increased 1-OH-P excretion in all members of the experimental group compared with the control group using a non-coal tar antidandruff shampoo. It is suggested that repeated use of coal tar shampoo would result in a high internal dose of carcinogenic PAH. 5 refs., 1 fig.

  5. Determination of basic azaarenes and polynuclear aromatic hydrocarbons in airborne particulate matter by gas chromatography

    DEFF Research Database (Denmark)

    Nielsen, Torben; Clausen, Peraxel; Jensen, Finn Palmgren

    1986-01-01

    phase (adjusted to pH 14 with potassium hydroxide) with dichloromethane, and determined by capillary gas chromatography (g.c.) with a nitrogen-sensitive detector. The PAH in the toluene phase are isolated by means of semipreparative high-performance liquid chromatography and liquid-liquid extraction......Polynuclear aromatic hydrocarbons (PAH) and their nitrogen analogs, basic azaarenes, are extracted from samples of airborne particulate matter by toluene with ultrasonic treatment. The basic azaarenes are extracted from the toluene phase with phosphoric acid, re-extracted from the phosphoric acid...

  6. A DFT-based toxicity QSAR study of aromatic hydrocarbons to Vibrio fischeri: Consideration of aqueous freely dissolved concentration.

    Science.gov (United States)

    Wang, Ying; Yang, Xianhai; Wang, Juying; Cong, Yi; Mu, Jingli; Jin, Fei

    2016-05-01

    In the present study, quantitative structure-activity relationship (QSAR) techniques based on toxicity mechanism and density functional theory (DFT) descriptors were adopted to develop predictive models for the toxicity of alkylated and parent aromatic hydrocarbons to Vibrio fischeri. The acute toxicity data of 17 aromatic hydrocarbons from both literature and our experimental results were used to construct QSAR models by partial least squares (PLS) analysis. With consideration of the toxicity process, the partition of aromatic hydrocarbons between water phase and lipid phase and their interaction with the target biomolecule, the optimal QSAR model was obtained by introducing aqueous freely dissolved concentration. The high statistical values of R(2) (0.956) and Q(CUM)(2) (0.942) indicated that the model has good goodness-of-fit, robustness and internal predictive power. The average molecular polarizability (α) and several selected thermodynamic parameters reflecting the intermolecular interactions played important roles in the partition of aromatic hydrocarbons between the water phase and biomembrane. Energy of the highest occupied molecular orbital (E(HOMO)) was the most influential descriptor which dominated the toxicity of aromatic hydrocarbons through the electron-transfer reaction with biomolecules. The results demonstrated that the adoption of freely dissolved concentration instead of nominal concentration was a beneficial attempt for toxicity QSAR modeling of hydrophobic organic chemicals. PMID:26812082

  7. Calculation of emissions into rivers in Germany using the MONERIS model. Nutrients, heavy metals and polycyclic aromatic hydrocarbons; Berechnung von Stoffeintraegen in die Fliessgewaesser Deutschlands mit dem Modell MONERIS. Naehrstoffe, Schwermetalle und Polyzyklische aromatische Kohlenwasserstoffe

    Energy Technology Data Exchange (ETDEWEB)

    Fuchs, Stephan; Scherer, Ulrike; Wander, Ramona [Karlsruher Institut fuer Technologie, Karlsruhe (Germany). Inst. fuer Wasser und Gewaesserentwicklung; Behrendt, Horst; Venohr, Markus; Optiz, Dieter [Leibniz-Institut fuer Gewaesseroekologie und Binnenfischerei im Forschungsverbund Berlin e.V., Berlin (Germany); Hillenbrand, Thomas; Marscheider-Weidemann, Frank; Goetz, Thomas [Fraunhofer-Institut fuer System- und Innovationsforschung, Karlsruhe (Germany)

    2010-09-15

    The aim of both projects was a methodological development of the MONERIS model to quantify emissions from point and diffuse sources into Germany's surface waters. Both projects are based on consistent sub-basins and the according basic data as well as homogenous calculation algorithms that are adapted to the specifications of each substance group. The research encompasses Germany's large river basins as well as their catchment areas outside Germany and in total covers an area of 650,000 km{sup 2}. This was divided into 3456 analytical units (2759 of those in Germany), the average catchment areas being 190 km{sup 2} (135 km{sup 2} in Germany). All input data was collected and preprocessed with the highest spatial and temporal resolution possible based on the detailed topology. The modelling was performed in individual annual steps for the period between 1983-2005. For the evaluation of the temporal trends the data was aggregated for the periods 1983-1987 (''1985''), 1993-1997 (''1995''), 1998-2002 (''2000'') and 2003-2005 (''2005'') to soften the impact of hydrological influences. The basic data and model results for all sub-basins, years and substance groups of both projects were merged into one database. Additionally, a web-based graphical user interface was developed to visualise the emissions for any area aggregation can be visualised. The completion of both projects delivered for the first time ever homogenous instruments that can identify the most important sources and contamination hotspots for different relevant substance groups in larger river basins which can then serve as a basis for further analyses to achieve efficient measures to reduce pollution. (orig.)

  8. Global distribution and Gas-particle Partitioning of Polycyclic Aromatic Hydrocarbons - a Modelling Study

    Science.gov (United States)

    Lammel, G.; Sehili, A. M.

    2009-04-01

    Polycyclic aromatic hydrocarbons (PAHs) are emitted in all combustion processes. Some undergo re-volatilisation (multi-hopping). Little is known about degradation pathways and the processes determining gas-particle partitioning (Lohmann & Lammel, 2004). Distribution and fate have no been studied on the global scale so far (except for emissions in Europe and Russia; Sehili & Lammel, 2007). Anthracene (ANT), fluoranthene (FLT) and benzo[a]pyrene (BAP) have been studied under present-day climate and each 3 scenarios of atmospheric degradation and gas-particle partitioning using an atmospheric general circulation model with embedded dynamic aerosol submodel, ECHAM-HAM (Stier et al., 2005) and re-volatilization from ground compartments (Semeena et al., 2006). 10 years were simulated with a time-step of 30 min and 2.8°x2.8° and 19 levels. Emissions were compiled based on emission factors in 27 major types of combustion technologies, scaled to 141 combustion technologies and their global distribution as of 1996 (1°x1°) according to fuel type and the PM1 emission factor (Bond et al., 2004). The emissions were entried uniformly throughout the entire simulation time. Scenarios tested: AD = adsorption (according to the Junge empirical relationship; Pankow, 1987), OB = absorption in organic matter and adsorption to soot (Lohmann & Lammel, 2004) without and DP = with degradation in the atmospheric particulate phase. Gas-particle partitioning in air influences drastically the atmospheric cycling, total environmental fate (e.g. compartmental distributions) and the long-range transport potential (LRTP) of the substances studied. The LRTP is mostly regional. Comparison with observed levels indicate that degradation in the particulate phase must be slower than in the gas-phase. Furthermore, the levels of semivolatile PAHs (ANT and FLT) at high latitudes and a European mid latitude site cannot be explained by partitioning due to adsorption alone, but point to both absorption into

  9. Distribution and fate of aliphatic and aromatic hydrocarbons in Antarctic fauna and environment

    Science.gov (United States)

    Platt, H. M.; Mackie, P. R.

    1980-03-01

    With the depletion of oil resources in more accessible areas, those of remote regions are being considered or indeed are now being exploited. In many of these regions, especially the polar ones, little is known of the effects such exploitation will have on the environment. But it is known that the ecosystems are often subject to great stress by natural climatic conditions and additional burdens imposed by man may have catastrophic environmental effects. South Georgia, a sub-Antarctic island, has a history of industrial activity mainly concerned with whaling operations that peaked around 1925-1935 but has since declined to virtually nothing. Studies of the ecology of the area provided a unique opportunity to assess the long-term effects that such activities had on the ecosystem. Off the whaling stations a considerable amount of waste material, including fuel oil, was released into the bays and inevitably some of this material was deposited in the sediments. Chemical evidence in the form of both paraffinic and aromatic hydrocarbons still persists in the sediments. The implications of this persistence in relation to the possible influence of the low temperature conditions are discussed. The superficial sediments, marine biota and terrestrial plants, which since 1965 have returned virtually to a pristine state, contain hydrocarbons essentially similar to unpolluted areas around the coast of Britain. Relatively high levels of carcinogenic/mutagenic polynuclear aromatic hydrocarbons in surface sediments suggests a world-wide background of abiogenic hydrocarbons probably disseminated by airborne transport. This appears to indicate that contamination reaches even remote parts of the world in relatively undiminished quantities.

  10. Analysis of aromatic hydrocarbons in overburden from coal mines: Assessment of the environmental impact

    International Nuclear Information System (INIS)

    Bituminous coals are known to contain significant amounts of petroleum-like hydrocarbons trapped in the pore system of the macromolecular network. With increasing thermal stress acting upon coals under the particular conditions in their deposits, the relative amount of volatile aromatic hydrocarbons within the trapped bitumen increases until the coal reaches the rank of medium-volatile bituminous coals. Coking coals particularly are rich in compounds such as benzene, biphenyl, naphthalene, and their alkylated derivatives. Potential hazardous environmental impact of these hydrocarbons has to be considered when mining or reclaiming overburden because approximately 10% overburden material related to coal mining is coal. Exposure to long-term weathering destroys the pore system of coals, which might result in a release of highly volatile bituminous coal constituents into the atmosphere. This view is supported by analyses of coals present in overburden material. In the present study, the on-line combination of thermodesorption coupled to gas chromatography and mass spectrometry is shown to be an appropriate tool for the detection and quantitation of hydrocarbons of a wide boiling temperature range present in solid sample material. The method is preferentially suitable for the analysis of highly volatile constituents such as benzene, toluene, and xylenes, which are not quantitatively analyzed using conventional solvent-extraction methods

  11. Oil and gas potential assessment for coal measure source rocks on absolute concentration of n-alkanes and aromatic hydrocarbons

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Absolute concentration of normal alkanes(n-alkanes) and aromatic hydrocarbons in bitumen extracted from source rocks in the period of thermodegradation from Turpan-Hami Basin suggests that aromatic hydrocarbons are dominant in coal and carbargilite while n-alkanes are dominant in mudstones. Bulkrock analysis and gas chromatograph/mass spectrum(GC-MS) of source rocks shows aromatic hydrocarbons are dominant in total ion chromatograms(TIC) of samples with poor perhydrous macerals while n-alkanes are dominant in TICs of samples with abundant perhydrous macerals. The identification of oil-prone and gas prone property based on GC-MS of bitumen "A" together with bulkrock analysis indicates that source rocks from Shengbei area are more oil-prone while source rocks from Qiudong and Xiaocaohu areas are more gas-prone,coinciding with the distribution of oil and gas reservoirs in Taibei Sag. Ratios used to identify oil-prone and gas-prone property for source rocks from Turpan Basin are proposed:n-alkanes >110 μg·mg-1,aromatics <15 μg·mg-1,and n-alkanes/aromatics >8 for oil-prone source rock bitumen while n-alkanes<82 μg·mg-1,aromatics >40 μg·mg-1,and n-alkanes/aromatics <1.5 for gas-prone source rock bitumen.

  12. Subway construction activity influence on polycyclic aromatic hydrocarbons in fine particles: Comparison with a background mountainous site

    Science.gov (United States)

    Kong, Shaofei; Li, Xuxu; Li, Qi; Yin, Yan; Li, Li; Chen, Kui; Liu, Dantong; Yuan, Liang; Pang, Xiaobing

    2015-07-01

    Intensive construction activities worsened the surrounding atmospheric environment in China. Eighteen polycyclic aromatic hydrocarbons (PAHs) in fine particles (PM2.5) were collected at a subway construction site (SC) of Nanjing and compared with a regional background mountainous site (BM) to examine the influence of anthropogenic activities on concentrations, sources and health risks of PAHs. Average PAH concentrations at SC were higher than BM at a factor of about 5.9. All PAH species at SC were higher than BM, with the SC/BM ratios ranging from 1.3 (NaP) to 10.3 (BaP). PAH profiles differed for the two sites. The SC site had higher mass fractions of PAHs from coal combustion and vehicle emission, while the BM site held higher mass percentages of PAHs from long-range transported wood combustion and industrial activities. Lower temperature at BM may lead to the higher mass percentages of low ring PAHs. Coal combustion, traffic emissions and biomass burning were the common sources for PAHs at both SC and BM. Construction workers were exposed to higher BaPeq concentrations, nearly ten times of the background site and their lifetime cancer risk reached to 0.6 per 1,000,000 exposed worker, owing to the influence of coal combustion, vehicle emission and industrial activities at the surroundings of SC.

  13. Daytime resolved analysis of polycyclic aromatic hydrocarbons in urban aerosol samples - impact of sources and meteorological conditions.

    Science.gov (United States)

    Sklorz, Martin; Schnelle-Kreis, Jürgen; Liu, Yongbo; Orasche, Jürgen; Zimmermann, Ralf

    2007-03-01

    Urban aerosol was collected in a summer and a winter campaign for 7 and 3 days, respectively. Low volume samples were taken with a time resolution of 160 min using a filter/sorption cartridge system extended by an ozone scrubber. Concentrations of mainly particle associated polycyclic aromatic hydrocarbons (PAH) and oxidised PAH (O-PAH) were determined by gas chromatography/high resolution mass spectrometry. The sampling site was located in the city centre of Augsburg, Germany, near major roads with high traffic volume. The daily concentrations and profiles were mainly governed by local emissions from traffic and domestic heating, as well as by the meteorological conditions. During the winter campaign, concentrations were more than 10 fold higher than during the summer campaign. Highest concentrations were found concurrent with low boundary layer heights and low wind speeds. Significant diurnal variation of the PAH profiles was observed. Enhanced influences of traffic related PAH on the PAH profiles were evident during daytime in summer, whereas emissions from hot water generation and domestic heating were obvious during the night time of both seasons. A general idea about the global meteorological situation was acquired using back trajectory calculations (NOAA ARL HYSPLIT4). Due to high local emissions in combination with low air exchange during the two sampling campaigns, effects of mesoscale transport were not clearly observable.

  14. Aliphatic and polycyclic aromatic hydrocarbons in sediments of the Slovenian coastal area (Gulf of Trieste, northern Adriatic).

    Science.gov (United States)

    Bajt, Oliver

    2012-12-01

    The distribution and sources of aliphatic and polycyclic aromatic hydrocarbons (PAH) were determined in sediments at seven sites around the Slovenian coastal area. The potential toxicological significance was also assessed using biological thresholds. The results of the analyses showed higher concentrations of hydrocarbons in the Port of Koper and in the Marina of Portoroz. The influence of pollution was also evident in rather higher concentrations of hydrocarbons in the surrounding area in the Bays of Koper and Piran. Concentrations of hydrocarbons decrease toward the central part of the Gulf of Trieste. The major component of the aliphatic fraction was the unresolved complex mixture. Concentrations of the total resolved aliphatic hydrocarbons were in a range from 689 to 3,164 ng g(-1). Concentrations of the total PAHs were between 330 and 1,173 ng g(-1). Polycyclic aromatic hydrocarbons are primarily of pyrolytic origin with some smaller contributions of the petrogenic, while the aliphatic are mostly of petrogenic origin with significant amounts of biogenic derived compounds of terrestrial and marine origin. Strong evidence of the diagenetic origin of perylene in the investigated area was also found. Quite a good linear relationship between PAH concentration and TOC and between aliphatic hydrocarbon concentrations and TOC was observed. The principal component analysis showed differences between the nearshore and offshore sites. In general, the investigated area is moderately contaminated by hydrocarbons. Concentrations of PAHs, hydrocarbons of high concern, are below the levels (effects range low and the effects range median) associated with adverse biological effects. PMID:22270593

  15. Evaluation of ambient air concentrations of polycyclic aromatic hydrocarbons in Germany from 1990 to 1998.

    Science.gov (United States)

    Fertmann, Regina; Tesseraux, Irene; Schümann, Michael; Neus, Hermann

    2002-03-01

    All available polycyclic aromatic hydrocarbon (PAH) concentration data in ambient air obtained over the past 10 years in Germany were evaluated to clarify whether it is justified to use benzo(a)pyrene (BaP) as a marker compound for the total PAH exposure. The data basis comprises annual mean concentrations from 1990 to 1998 supplied by the emission protection authorities of the federal states with additional information on the region, year and site of measurement. The data are very heterogeneous with respect to sample size, the number of individual PAHs analyzed, place of origin and year. Nine of 25 individual compounds with sufficient sample size (74German reunion and time characterize the distributive patterns, e.g., from 1991 to 1997, a significant decrease in BaP could be determined based on the data from North Rhine-Westphalia (1991, N=51, median 1.6 ng/m(3); 1997, N=45, median 0.7 ng/m(3); P

  16. Understanding Polycyclic Aromatic Hydrocarbon transfers at the catchment scale combining chemical and fallout radionuclides analyses

    Science.gov (United States)

    Gateuille, David; Evrard, Olivier; Lefevre, Irène; Moreau-Guigon, Elodie; Alliot, fabrice; Chevreuil, Marc; Mouchel, Jean-Marie

    2013-04-01

    Contamination of river water and sediment constitutes a major environmental issue for industrialized countries. Polycyclic Aromatic Hydrocarbons (PAHs) are a group of persistent organic pollutants characterized by two or more fused rings. In recent years, studies dealing with PAHs have grown in number. Some PAHs present indeed a high risk for environment and human health because of their carcinogenic and mutagenic properties. However, most of these studies focused on measuring PAH concentration in the different compartments of the environment (air, soil, sediment, water, etc.) In this context, there remains a lack of understanding regarding the various processes responsible for PAH transfers from one environmental compartment to another. Our study aims to quantify PAHs transfers at the catchment scale by combining chemical analysis with gamma spectrometry. Air, soil, river water and sediment samples (n=820) were collected in two upstream sub-catchments of the Seine River basin (France) during one year. Chemical analyses were carried out to determine PAHs concentrations in all samples. Furthermore, measurement of fallout radionuclides (Beryllium-7, Lead-210, Caesium-137) in both rainfall and river sediment provided a way to discriminate between freshly eroded sediment vs. resuspension of older material that previously deposited on the riverbed. This information is crucial to estimate PAH residence time and transfer velocities in the Seine River basin. The results show that the PAH behaviour varies from one subcatchment to the next. PAH transfers depend indeed on both the characteristics of the catchment (e.g. topography, presence of drained cropland in catchments) and the local anthropogenic pressures. A significant increase in atmospheric deposition of PAHs is observed during winter due to a larger number of sources (household heating). The 14-month study has also highlighted the seasonal variations of PAH fluxes, which are mainly related to the hydrological

  17. Evaluation of methods for predicting the toxicity of polycyclic aromatic hydrocarbon mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Reeves, W.; Barhoumi, R.; Burghardt, R.C. [and others] [Texas A & M University, College Station, TX (USA). Dept. of Veterinary Anatomy and Public Health and Department of Civil Engineering

    2001-04-15

    Risk assessments of polycyclic aromatic hydrocarbon mixtures are hindered by a lack of reliable information on the potency of both mixtures and their individual components. This paper examines methods for approximating the toxicity of polycyclic aromatic hydrocarbon (PAH) mixtures. PAHs were isolated from a coal tar and then separated by ring number using HPLC. Five fractions (A-E) were generated, each possessing a unique composition and expected potency. The toxicity of each fraction was measured in the Salmonella/mutagenicity assay and the Chick Embryo Screening Test (CHEST). Their abilities to induce ethoxyresorufin-O-deethylase and to inhibit gap junction intercellular communication in rat liver Clone 9 cells were also measured. In the Salmonella/mutagenicity assay, fractions were predicted to have potencies in the order C {gt} E {gt} B {gt} A. Toxic equivalency factors (TEFs) for fractions A-E were in the order E {ge} D {gt} C {gt} B {gt} A. TEF values were 20 652, 20 929, 441, 306 and 74.1 {mu}g of BaP equiv/g, respectively. A lack of agreement between assay-predicted potencies and chemical analysis-predicted potencies was observed with other assays and other methods of calculation. The results demonstrate the limitations of using a single method to predict the toxicity of a complex PAH mixture. 41 refs., 2 figs., 3 tabs.

  18. Polycyclic Aromatic Hydrocarbons (PAHs) in urban atmospheric particulate of NCR, Delhi, India

    Science.gov (United States)

    Sonwani, Saurabh; Amreen, Hassan; Khillare, P. S.

    2016-07-01

    The present study identifies the particulate Polycyclic Aromatic hydrocarbons (PAHs) and their sources in ambient atmosphere of Delhi, India. PM10 (aerodynamic diameter, ≤10 μm) samples were collected weekly at two residential areas from July 2013 to January 2014. First sampling site was located in centre of the city, while other was at city's background (located in South-East direction of the Delhi). PM10 was collected on Whatman GF/A (8"x10") glass fibre filters using High-Volume sampler having a constant flow rate of 1.10 m3/min. A total of 55 samples, 27 from city centre and 28 from background site were collected during sampling period, covering two different seasons. The samples were analysed for determination of 16 Polycyclic Aromatic Hydrocarbons by using High Performance Liquid Chromatography (HPLC) system (Waters, USA). A source apportionment study using Molecular Diagnostic Ratio (MDR) and Principal Component Analysis (PCA) were conducted for both sampling sites in order to identify the potential PAHs sources in Delhi. MDR was used for the preliminary identification of sources and PCA was used for further confirmation of the PAH sources at both the sites in Delhi. Results indicated towards traffic and coal combustion related sources as dominant contributors of urban atmospheric PAHs in Delhi.

  19. Combined effect of urinary monohydroxylated polycyclic aromatic hydrocarbons and impaired lung function on diabetes.

    Science.gov (United States)

    Hou, Jian; Sun, Huizhen; Xiao, Lili; Zhou, Yun; Yin, Wenjun; Xu, Tian; Cheng, Juan; Chen, Weihong; Yuan, Jing

    2016-07-01

    Associations of type 2 diabetes with exposure to polycyclic aromatic hydrocarbons and reduced lung function have been reported. The aim of the present study was to investigate effect of reduced lung function and exposure to background PAHs on diabetes. A total of 2730 individuals were drawn from the Wuhan-Zhuhai (WHZH) Cohort Study (n=3053). Participants completed physical examination, measurement of lung function and urinary monohydroxylated polycyclic aromatic hydrocarbons (OH-PAHs). Risk factors for type 2 diabetes were identified by multiple logistic regression analysis, and the presence of additive interaction between levels of urinary OH-PAHs and lower lung function was evaluated by calculation of the relative excess risk due to interaction (RERI) and attributable proportion due to interaction (AP). Urinary OH-PAHs levels was positively associated with type 2 diabetes among individuals with impaired lung function (pFEV1, odd ratio (OR): 0.664, 95% confidence interval (CI): 0.491-0.900) and forced vital capacity (FVC, OR: 0.693, 95% CI: 0.537-0.893) were negatively associated with diabetes among individuals. Additive interaction of higher urinary levels of OH-PAHs and lower FVC (RERI: 0.679, 95% CI: 0.120-1.238); AP: 0.427, 95% CI: 0.072-0.782) was associated with diabetes. Exposure to background PAHs was related to diabetes among individuals with lower lung function. Urinary levels of OH-PAHs and reduced lung function had an additive effect on diabetes. PMID:27136672

  20. Sequential accelerated solvent extraction of polycyclic aromatic hydrocarbons with different solvents: performance and implication.

    Science.gov (United States)

    Ma, Xiaoxuan; Ran, Yong; Gong, Jian; Chen, Diyun

    2010-01-01

    Sixteen USEPA priority polycyclic aromatic hydrocarbons (PAHs) extracted by Soxhlet extraction (S-PAHs) with dichloromethane and routine accelerated solvent extraction (A-PAHs) with 1:1 toluene/methanol, respectively, were investigated in 24 soil samples from two cities in the center of the Pearl River Delta, South China. Polycyclic aromatic hydrocarbons, methylphenanthrene and perylene, in two soils, two sediments, and an immature oil shale were also sequentially extracted by accelerated solvent extraction (ASE) with each of four different organic solvents for three times. The A-PAHs' concentrations are 2.41 times the S-PAHs' concentrations. For sequential three ASEs, PAHs in the first extract account for 56 to 67% of their total concentrations in the sequential three extractions and toluene displays the best extraction performance among the four solvents. Diagnostic ratios of PAHs in Soxhlet extraction, routine ASE, and sequential ASE with each solvent for a given sample are very similar, suggesting their identical petrogenic and pyrogenic sources in the soils and sediments. But the PAH ratios for the shale have an obvious petrogenic origin. The perylene/5-ring PAH ratios indicate a diagenetic source, especially in the shale and sediments. The correlation analysis shows that A-PAHs/S-PAHs is better associated with the contents of total organic carbon (TOC) than those of black carbon (BC). The above results indicate the significant petrogenic origin of PAHs and the important effect of organic matter on their extraction and distribution in the investigated field soils/sediments. PMID:21284305

  1. Brine-induced advection of dissolved aromatic hydrocarbons to arctic bottom waters

    International Nuclear Information System (INIS)

    Extruded brine, generated during sea ice formation in nearshore arctic waters, will sink to the bottom and can form a stable bottom boundary layer. This layer can persist for periods of up to 4-6 months. Limited quantities of dissolved aromatic hydrocarbons resulting from a spill of crude oil or refined petroleum distillate products during periods of ice growth can be transported as conservative components to the benthos with sinking brine. Once incorporated into the stable bottom boundary layer, these aromatic components are no longer subject to loss by evaporative processes, and they only can be diluted by ultimately mixing with uncontaminated water masses, a process that proceeds slowly throughout the ice-covered period. This mechanism for the transport of dissolved hydrocarbons has been demonstrated through a laboratory test-tank simulation and a chemical/physical oceanographic field program conducted in the Chukchi Sea near Pt. Frankline, AK (March 1985). The results are pertinent to shallow nearshore oil and gas exploration, development, production, and transportation activities in high latitude marine systems

  2. Oxidation of polycyclic aromatic hydrocarbons using partially purified laccase from residual compost of agaricus bisporus

    Energy Technology Data Exchange (ETDEWEB)

    Mayolo-Deloisa, K. [Center for Biotechnology Research, Autonomous University of Morelos State, Cuernavaca, Morelos (Mexico); Center for Biotechnology-FEMSA, Monterrey Institute of Technology, Campus Monterrey, Monterrey (Mexico); Machin-Ramirez, C. [Center for Biotechnology Research, Autonomous University of Morelos State, Cuernavaca, Morelos (Mexico); Faculty of Chemical Sciences and Engineering, Autonomous University of Morelos State, Cuernavaca, Morelos (Mexico); Rito-Palomares, M. [Center for Biotechnology-FEMSA, Monterrey Institute of Technology, Campus Monterrey, Monterrey (Mexico); Trejo-Hernandez, M.R. [Center for Biotechnology Research, Autonomous University of Morelos State, Cuernavaca, Morelos (Mexico)

    2011-08-15

    Laccase partially purified from residual compost of Agaricus bisporus by an aqueous two-phase system (Lac ATPS) was used in degrading polycyclic aromatic hydrocarbons: fluorene (Flu), phenanthrene (Phe), anthracene (Ant), benzo[a]pyrene (BaP), and benzo[a]anthracene (BaA). The capacity of the enzyme to oxidize polyaromatic compounds was compared to that of the crude laccase extract (CE). After treatment of 72 h, Lac ATPS and CE were not capable of oxidizing Flu and Phe, while Ant, BaP, and BaA were oxidized, resulting in percentages of oxidation of 11.2 {+-} 1, 26 {+-} 2, and 11.7 {+-} 4 % with CE, respectively. When Lac ATPS was used, the following percentages of oxidation were obtained: 11.4 {+-} 3 % for Ant, 34 {+-} 0.1 % for BaP, and 13.6 {+-} 2 % for BaA. The results reported here demonstrate the potential application of Lac ATPS for the oxidation of polycyclic aromatic hydrocarbons. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Assessment of atmospheric distribution of polychlorinated biphenyls and polycyclic aromatic hydrocarbons using polyparameter model

    Directory of Open Access Journals (Sweden)

    Turk-Sekulić Maja M.

    2011-01-01

    Full Text Available Results of partial or total destruction of industrial plants, military targets, infrastructure, uncontrolled fires and explosions during the conflict period from 1991 to 1999, at the area of Western Balkans, were large amounts of hazardous organic matter that have been generated and emitted in the environment. In order to assess gas/particle partition of seven EPA polychlorinated biphenyls and sixteen EPA polycyclic aromatic hydrocarbons, twenty air samples have been collected at six urban, industrial and highly contaminated localities in Vojvodina. Hi-Vol methodology has been used for collecting ambiental air samples, that simultaneously collects gaseous and particulate phase with polyurethane foam filters (PUF and glass fiber filters (GFF. PUF and GFF filters have been analyzed, and concentration levels of gaseous PCBs and PAHs molecules in gaseous and particulate phase were obtained, converted and expressed through fraction of individual compounds sorbed onto particulate phase of the sample, in total detected quantity. Experimentally gained gas/particle partitioning values of PCBs and PAHs molecules have been compared with PP-LFER model estimated values. Significant deviation has been noticed during comparative analysis of estimated polyparameter model values for complete set of seven PCBs congeners. Much better agreement of experimental and estimated values is for polycyclic aromatic hydrocarbons, especially for molecules with four rings. These results are in a good correlation with literature data where polyparameter model has been used for predicting gas/particle partition of studied group of organic molecules.

  4. Differential scanning calorimetry method for purity determination: A case study on polycyclic aromatic hydrocarbons and chloramphenicol

    Energy Technology Data Exchange (ETDEWEB)

    Kestens, V., E-mail: vikram.KESTENS@ec.europa.eu [European Commission - Joint Research Centre, Institute for Reference Materials and Measurements (IRMM), Retieseweg 111, 2440 Geel (Belgium); Zeleny, R.; Auclair, G.; Held, A.; Roebben, G.; Linsinger, T.P.J. [European Commission - Joint Research Centre, Institute for Reference Materials and Measurements (IRMM), Retieseweg 111, 2440 Geel (Belgium)

    2011-09-20

    Highlights: {yields} Purity assessment of polycyclic aromatic hydrocarbons and chloramphenicol by DSC. {yields} DSC results compared with traditional purity methods. {yields} Different methods give different results, multiple method approach recommended. {yields} DSC sensitive to impurities that have similar structures as main component. - Abstract: In this study the validity and suitability of differential scanning calorimetry (DSC) to determine the purity of selected polycyclic aromatic hydrocarbons and chloramphenicol has been investigated. The study materials were two candidate certified reference materials (CRMs), 6-methylchrysene and benzo[a]pyrene, and two different batches of commercially available highly pure chloramphenicol. The DSC results were compared with those obtained by other methods, namely gas and liquid chromatography with mass spectrometric detection, liquid chromatography with diode array detection, and quantitative nuclear magnetic resonance. The purity results obtained by these different analytical methods confirm the well-known challenges of comparing results of different method-defined measurands. In comparison with other methods, DSC has a much narrower working range. This limits the applicability of DSC as purity determination method, for instance during the assignment of the purity value of a CRM. Nevertheless, this study showed that DSC can be a powerful technique to detect impurities that are structurally very similar to the main purity component. From this point of view, and because of its good repeatability, DSC can be considered as a valuable technique to investigate the homogeneity and stability of candidate purity CRMs.

  5. Retention mechanism for polycyclic aromatic hydrocarbons in reversed-phase liquid chromatography with monomeric stationary phases.

    Science.gov (United States)

    Rafferty, Jake L; Siepmann, J Ilja; Schure, Mark R

    2011-12-23

    Reversed-phase liquid chromatography (RPLC) is the foremost technique for the separation of analytes that have very similar chemical functionalities, but differ only in their molecular shape. This ability is crucial in the analysis of various mixtures with environmental and biological importance including polycyclic aromatic hydrocarbons (PAHs) and steroids. A large amount of effort has been devoted to studying this phenomenon experimentally, but a detailed molecular-level description remains lacking. To provide some insight on the mechanism of shape selectivity in RPLC, particle-based simulations were carried out for stationary phases and chromatographic parameters that closely mimic those in an experimental study by Sentell and Dorsey [J. Chromatogr. 461 (1989) 193]. The retention of aromatic hydrocarbons ranging in size from benzene to the isomeric PAHs of the formula C(18)H(12) was examined for model RPLC systems consisting of monomeric dimethyl octadecylsilane (ODS) stationary phases with surface coverages ranging from 1.6 to 4.2 μmol/m(2) (i.e., stationary phases yielding low to intermediate shape selectivity) in contact with a 67/33 mol% acetonitrile/water mobile phase. The simulations show that the stationary phase acts as a very heterogeneous environment where analytes with different shapes prefer different spatial regions with specific local bonding environments of the ODS chains. However, these favorable retentive regions cannot be described as pre-existing cavities because the chain conformation in these local stationary phase regions adapts to accommodate the analytes.

  6. Questioning the existence of superconducting potassium doped phases for aromatic hydrocarbons

    Science.gov (United States)

    Heguri, Satoshi; Kobayashi, Mototada; Tanigaki, Katsumi

    2015-07-01

    Superconductivity in aromatic hydrocarbons doped with potassium (K) such as K3 [picene (PCN)] and K3 [phenanthrene (PHN)] is found for only armchair-type polycyclic aromatic hydrocarbon. In this paper the thermodynamics of the reaction processes of PHN or anthracene (AN, zigzag type) with K was studied using differential scanning calorimetry and x-ray diffraction. We show that PHN decomposes during the reaction, triggered by hydrogen abstraction, to give metal hydride KH and unknown amorphous. No stable doped phases exist in Kx(PHN ) with stoichiometries of x =1 -3 . However, in the case of AN, a stable doped phase forms. We claim that PHN, which has been reported to be energetically more stable in the ground state than AN by first principle calculations, is unstable upon doping. We also suggest that the superconductivity in K3(PCN ) is due to the misinterpretation of experimental data, which actually arises from ferromagnetic impurities. We have never detected the superconductivity above 2 K in these compounds. The superconductivity in both Kx(PHN ) and Kx(PCN ) is concluded to be highly questionable.

  7. Risk of human exposure to polycyclic aromatic hydrocarbons: A case study in Beijing, China

    International Nuclear Information System (INIS)

    Polycyclic aromatic hydrocarbons (PAHs) can cause adverse effects on human health. The relative contributions of their two major intake routes (diet and inhalation) to population PAH exposure are still unclear. We modeled the contributions of diet and inhalation to the overall PAH exposure of the population of Beijing in China, and assessed their human incremental lifetime cancer risks (ILCR) using a Mont Carlo simulation approach. The results showed that diet accounted for about 85% of low-molecular-weight PAH (L-PAH) exposure, while inhalation accounted for approximately 57% of high-molecular-weight PAH (H-PAH) exposure of the Beijing population. Meat and cereals were the main contributors to dietary PAH exposure. Both gaseous- and particulate-phase PAHs contributed to L-PAH exposure through inhalation, whereas exposure to H-PAHs was mostly from the particulate-phase. To reduce the cancer incidence of the Beijing population, more attention should be given to inhaled particulate-phase PAHs with considerable carcinogenic potential. - Highlights: • We modeled the contributions of diet and inhalation to population PAH exposure. • Diet contributed 85% of population exposure to low molecular-weight PAHs. • Inhalation contributed 57% of population exposure to high molecular-weight PAHs. • The PAH exposure level with body-weight adjustment decreased with age increasing. • The population cancer risk of PAH exposure is lower than the serious risk level. - The exposure of the Beijing population to carcinogenic polycyclic aromatic hydrocarbons was mainly from inhaled particulate matter

  8. Polycyclic aromatic hydrocarbons in Recent lake sediments—I. Compounds having anthropogenic origins

    Science.gov (United States)

    Wakeham, Stuart G.; Schaffner, Christian; Giger, Walter

    1980-03-01

    Polycyclic aromatic hydrocarbons (PAH) in sediment cores from Lake Lucerne, Lake Zürich, and Greifensee, Switzerland, and Lake Washington, northwest U.S.A., have been isolated, identified and quantified by glass capillary gas chromatography and gas chromatography/mass spectrometry. Surface sediment layers are greatly enriched in PAH—up to 40 times—compared to deeper layers. In addition, concentration increases in upper sediments generally correspond to increasing industrialization and urbanization in the catchment basins of the lakes. Few PAH could be detected in pre-industrial revolution sediments, indicating that background levels for most PAH in aquatic sediments are extremely low. These results are consistent with an anthropogenic source for most of the aromatic hydrocarbons present in the modern sediments. A comparison of PAH distributions in the sediments and in possible source materials shows that urban runoff of street dust may be the most important PAH input to these lacustrine sediments. There is evidence that a significant contribution to the PAH content of street dust comes from material associated with asphalt.

  9. City air pollution of polycyclic aromatic hydrocarbons and other mutagens: occurrence, sources and health effects

    DEFF Research Database (Denmark)

    Nielsen, T.; Ejsing Jørgensen, Hans; Larsen, J.C.;

    1996-01-01

    The presence of polycyclic aromatic hydrocarbons (PAH), mutagens and other air pollutants was investigated in a busy street in central Copenhagen and in a park area adjacent to the street. The winter concentration of benzo(a)pyrene was 4.4+/-1.2 ng/m(3) in the street air and 1.4+/-0.6 ng/m(3) in ...... was estimated to be 40%. Four different approaches to evaluate the health effects are discussed. The direct effect of PAH air pollution, and other mutagens, is considered to be a maximum of five lung cancer cases each year out of one million people.......The presence of polycyclic aromatic hydrocarbons (PAH), mutagens and other air pollutants was investigated in a busy street in central Copenhagen and in a park area adjacent to the street. The winter concentration of benzo(a)pyrene was 4.4+/-1.2 ng/m(3) in the street air and 1.4+/-0.6 ng/m(3...

  10. Formation and emission of large furans and oxygenated hydrocarbons from flames.

    Science.gov (United States)

    Johansson, K Olof; Dillstrom, Tyler; Monti, Matteo; El Gabaly, Farid; Campbell, Matthew F; Schrader, Paul E; Popolan-Vaida, Denisia M; Richards-Henderson, Nicole K; Wilson, Kevin R; Violi, Angela; Michelsen, Hope A

    2016-07-26

    Many oxygenated hydrocarbon species formed during combustion, such as furans, are highly toxic and detrimental to human health and the environment. These species may also increase the hygroscopicity of soot and strongly influence the effects of soot on regional and global climate. However, large furans and associated oxygenated species have not previously been observed in flames, and their formation mechanism and interplay with polycyclic aromatic hydrocarbons (PAHs) are poorly understood. We report on a synergistic computational and experimental effort that elucidates the formation of oxygen-embedded compounds, such as furans and other oxygenated hydrocarbons, during the combustion of hydrocarbon fuels. We used ab initio and probabilistic computational techniques to identify low-barrier reaction mechanisms for the formation of large furans and other oxygenated hydrocarbons. We used vacuum-UV photoionization aerosol mass spectrometry and X-ray photoelectron spectroscopy to confirm these predictions. We show that furans are produced in the high-temperature regions of hydrocarbon flames, where they remarkably survive and become the main functional group of oxygenates that incorporate into incipient soot. In controlled flame studies, we discovered ∼100 oxygenated species previously unaccounted for. We found that large alcohols and enols act as precursors to furans, leading to incorporation of oxygen into the carbon skeletons of PAHs. Our results depart dramatically from the crude chemistry of carbon- and oxygen-containing molecules previously considered in hydrocarbon formation and oxidation models and spearhead the emerging understanding of the oxidation chemistry that is critical, for example, to control emissions of toxic and carcinogenic combustion by-products, which also greatly affect global warming. PMID:27410045

  11. Contamination of Runoff Water at Gdańsk Airport (Poland) by Polycyclic Aromatic Hydrocarbons (PAHs) and Polychlorinated Biphenyls (PCBs)

    OpenAIRE

    Jacek Namieśnik; Anna Maria Sulej; Żaneta Polkowska

    2011-01-01

    Airport runoff can contain high concentrations of various pollutants, in particular polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), the environmental levels of which have to be monitored. Airport runoff water samples, collected at the Gdańsk-Rębiechowo Airport from 2008 to 2009, were analysed for PAHs and PCBs by gas chromatography. The aromatic fractions were separated by liquid-liquid extraction and analysed by GC/MS. Total PAH concentrations were 295–6,758 ng/...

  12. Kekulé-based Valence Bond Model.Ⅱ. Diels-Alder Reactivity of Polycyclic Aromatic Hydrocarbons

    Institute of Scientific and Technical Information of China (English)

    MA,Jing(马晶); LI,Shu-Hua(黎书华); JIANG,Yuan-Sheng(江元生)

    2002-01-01

    The Kekule-based valence bond ( VB ) method was employed to study the ground state properties of 52 polycyclic aromatic hydrocarbons. The reactivity indices defined upon our VB calculations were demonstrated to be capable of quantitatively interpreting the secnd order rate constants of the Diels-Alder reactions. The qualitative trends of the reactivities of many homologous series can be also explained based on the local aromaticity index defined in this work.

  13. Functional Gene Markers for Fumarate-Adding and Dearomatizing Key Enzymes in Anaerobic Aromatic Hydrocarbon Degradation in Terrestrial Environments.

    Science.gov (United States)

    von Netzer, Frederick; Kuntze, Kevin; Vogt, Carsten; Richnow, Hans H; Boll, Matthias; Lueders, Tillmann

    2016-01-01

    Anaerobic degradation is a key process in many environments either naturally or anthropogenically exposed to petroleum hydrocarbons. Considerable advances into the biochemistry and physiology of selected anaerobic degraders have been achieved over the last decades, especially for the degradation of aromatic hydrocarbons. However, researchers have only recently begun to explore the ecology of complex anaerobic hydrocarbon degrader communities directly in their natural habitats, as well as in complex laboratory systems using tools of molecular biology. These approaches have mainly been facilitated by the establishment of a suite of targeted marker gene assays, allowing for rapid and directed insights into the diversity as well as the identity of intrinsic degrader populations and degradation potentials established at hydrocarbon-impacted sites. These are based on genes encoding either peripheral or central key enzymes in aromatic compound breakdown, such as fumarate-adding benzylsuccinate synthases or dearomatizing aryl-coenzyme A reductases, or on aromatic ring-cleaving hydrolases. Here, we review recent advances in this field, explain the different detection methodologies applied, and discuss how the detection of site-specific catabolic gene markers has improved the understanding of processes at contaminated sites. Functional marker gene-based strategies may be vital for the development of a more elaborate population-based assessment and prediction of aromatic degradation potentials in hydrocarbon-impacted environments. PMID:26959523

  14. Biodegradation of polycyclic aromatic hydrocarbons by Trichoderma species: a mini review.

    Science.gov (United States)

    Zafra, German; Cortés-Espinosa, Diana V

    2015-12-01

    Fungi belonging to Trichoderma genus are ascomycetes found in soils worldwide. Trichoderma has been studied in relation to diverse biotechnological applications and are known as successful colonizers of their common habitats. Members of this genus have been well described as effective biocontrol organisms through the production of secondary metabolites with potential applications as new antibiotics. Even though members of Trichoderma are commonly used for the commercial production of lytic enzymes, as a biological control agent, and also in the food industry, their use in xenobiotic biodegradation is limited. Trichoderma stands out as a genus with a great range of substrate utilization, a high production of antimicrobial compounds, and its ability for environmental opportunism. In this review, we focused on the recent advances in the research of Trichoderma species as potent and efficient aromatic hydrocarbon-degrading organisms, as well as aimed to provide insight into its potential role in the bioremediation of soils contaminated with heavy hydrocarbons. Several Trichoderma species are associated with the ability to metabolize a variety of both high and low molecular weight polycyclic aromatic hydrocarbons (PAHs) such as naphthalene, phenanthrene, chrysene, pyrene, and benzo[a]pyrene. PAH-degrading species include Trichoderma hamatum, Trichoderma harzianum, Trichoderma reesei, Trichoderma koningii, Trichoderma viride, Trichoderma virens, and Trichoderma asperellum using alternate enzyme systems commonly seen in other organisms, such as multicooper laccases, peroxidases, and ring-cleavage dioxygenases. Within these species, T. asperellum stands out as a versatile organism with remarkable degrading abilities, high tolerance, and a remarkable potential to be used as a remediation agent in polluted soils.

  15. Biodegradation of polycyclic aromatic hydrocarbons by Trichoderma species: a mini review.

    Science.gov (United States)

    Zafra, German; Cortés-Espinosa, Diana V

    2015-12-01

    Fungi belonging to Trichoderma genus are ascomycetes found in soils worldwide. Trichoderma has been studied in relation to diverse biotechnological applications and are known as successful colonizers of their common habitats. Members of this genus have been well described as effective biocontrol organisms through the production of secondary metabolites with potential applications as new antibiotics. Even though members of Trichoderma are commonly used for the commercial production of lytic enzymes, as a biological control agent, and also in the food industry, their use in xenobiotic biodegradation is limited. Trichoderma stands out as a genus with a great range of substrate utilization, a high production of antimicrobial compounds, and its ability for environmental opportunism. In this review, we focused on the recent advances in the research of Trichoderma species as potent and efficient aromatic hydrocarbon-degrading organisms, as well as aimed to provide insight into its potential role in the bioremediation of soils contaminated with heavy hydrocarbons. Several Trichoderma species are associated with the ability to metabolize a variety of both high and low molecular weight polycyclic aromatic hydrocarbons (PAHs) such as naphthalene, phenanthrene, chrysene, pyrene, and benzo[a]pyrene. PAH-degrading species include Trichoderma hamatum, Trichoderma harzianum, Trichoderma reesei, Trichoderma koningii, Trichoderma viride, Trichoderma virens, and Trichoderma asperellum using alternate enzyme systems commonly seen in other organisms, such as multicooper laccases, peroxidases, and ring-cleavage dioxygenases. Within these species, T. asperellum stands out as a versatile organism with remarkable degrading abilities, high tolerance, and a remarkable potential to be used as a remediation agent in polluted soils. PMID:26498812

  16. Size-distribution of airborne polycyclic aromatic hydrocarbons and other organic source markers in the surroundings of a cement plant powered with alternative fuels.

    Science.gov (United States)

    Sánchez-Soberón, Francisco; van Drooge, Barend L; Rovira, Joaquim; Grimalt, Joan O; Nadal, Martí; Domingo, José L; Schuhmacher, Marta

    2016-04-15

    The distributions of polycyclic aromatic hydrocarbons (PAHs) and molecular tracer organic compounds for biomass combustion, traffic emissions, soil dust, and secondary aerosol processing have been studied in three fractions of ambient air particulate matter (PM10, 2.5, and 1) collected in the vicinity of a cement plant. PAH concentrations were used to estimate the carcinogenic risks in humans. Combustion related compounds, including PAHs, and those from secondary aerosol processing, predominated in the finest (PMlaw. Exposure and inhalation carcinogenic risks from total PAHs were below the EPA threshold of acceptable risk (1·10(-6)). PMID:26859698

  17. Comparison of three different in vitro mutation assays used for the investigation of cytochrome P450-mediated mutagenicity of nitro-polycyclic aromatic hydrocarbons

    NARCIS (Netherlands)

    Kappers, W.A.; Och, F.M.M. van; Groene, E.M. de; Horbach, G.J.

    2000-01-01

    Three different in vitro mutation assays were used to investigate the involvement of cytochrome P450 enzymes in the activation of the nitro- polycyclic aromatic hydrocarbons (nitroPAHs) 1-nitropyrene and 2- nitrofluorene and their reduced metabolites amino-polycyclic aromatic hydrocarbons (aminoPAHs

  18. 33 CFR 157.132 - Cargo tanks: Hydrocarbon vapor emissions.

    Science.gov (United States)

    2010-07-01

    ... SECURITY (CONTINUED) POLLUTION RULES FOR THE PROTECTION OF THE MARINE ENVIRONMENT RELATING TO TANK VESSELS CARRYING OIL IN BULK Crude Oil Washing (COW) System on Tank Vessels Design, Equipment, and Installation § 157.132 Cargo tanks: Hydrocarbon vapor emissions. Each tank vessel having a COW system under §...

  19. {Polycyclic aromatic hydrocarbons (PAHs) and aliphatic hydrocarbons in gas and particle phases in two sites of Mexico: MILAGRO project}

    Science.gov (United States)

    Amador-Muñoz, O.; Villalobos-Pietrini, R.; Castro, T.; Gaspariano-Larino, R.

    2009-04-01

    Aliphatic hydrocarbons are markers of anthropogenic and biogenic emission sources1; meanwhile PAHs are generated by incomplete combustion sources2. The last ones are important compounds due to their carcinogenic and mutagenic properties3,4. The aim of this study was to identify and quantify aliphatic hydrocarbons and PAHs in gas and particles phases of the atmospheric aerosol and to determine the day and night time behavior during the MILAGRO (Megacity Initiative: Local Global and Research Observations) campaign. The gas phase was collected on polyurethane foam, while particles less than 2.5 m (PM2.5) were collected on glass fiber filters covered with Teflon (TIGF, pallflex) of 8x10 in. Samplings were carried out with a high volume sampler (Tisch) with a flow of 1.13 m3 min-1 at two sites: Instituto Mexicano del Petróleo (T0) and Tecamac (T1) located at North and Northeast of Mexico City, respectively during day (7:00 am-7:00 pm) and night time (7:00 pm-7:00 am) from 1 to 29 of March, 2006. Ninteen PAHs and 23 aliphatic hydrocarbons from n-C13H28 to n-C35H72 were analyzed by gas chromatography coupled to mass spectrometry in impact mode. The samples were spiked with deuterads PAHs and aliphatics hydrocarbons before ultrasound extraction. Medians comparisons were made with Mann-Whitney U test. PAHs with molecular weight (MW) less than 228 g mol-1 were distributed in the gas phase, in both sites. Higher concentrations of PAHs ≥ 228 g mol-1 in PM2.5, were observed during night period (p

  20. Source apportionment of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in ambient air of an industrial region in Turkey

    Science.gov (United States)

    Aydin, Yagmur Meltem; Kara, Melik; Dumanoglu, Yetkin; Odabasi, Mustafa; Elbir, Tolga

    2014-11-01

    Source apportionment is generally applied to a time series of data collected at a single site. However, in a complex airshed containing several different sources, it may be helpful to collect samples from multiple sites to ensure that some of them have low contributions from specific sources, thus the boundaries can be properly defined. Ambient air polycyclic aromatic hydrocarbon (PAH) and polychlorinated biphenyls (PCB) samples (n = 160) were collected at 40 sites during four seasons (summer, fall, winter, and spring) between July 2009 and April 2010 in the heavily industrialized Aliaga region in Turkey to investigate their spatial, seasonal variations and to identify possible PAH and PCB sources. The newest version of EPA PMF (V5.0) having the capability of handling multiple site data was used for source apportionment. Five PAH sources were identified as biomass and coal combustion, iron-steel production, unburned crude oil and petroleum products, and diesel and gasoline exhaust emissions with contributions of 40, 27, 27, 3, and 3%, respectively. The sources of PCBs were identified as iron-steel production (consisting of steel-making and ship breaking activities), coal and wood combustion, and evaporative emissions from technical PCB mixtures with contributions of 57, 31, and 12%, respectively.

  1. Investigation of fixed wavelength fluorescence results for biliary metabolites of polycyclic aromatic hydrocarbons formed in Atlantic cod (Gadus morhua).

    Science.gov (United States)

    Pampanin, Daniela M; Kemppainen, Eeva K; Skogland, Karianne; Jørgensen, Kåre B; Sydnes, Magne O

    2016-02-01

    Fixed wavelength fluorescence (FF) and synchronous fluorescence scanning (SFS) of fish bile are commonly used methods to analyze for exposure to polycyclic aromatic hydrocarbons (PAHs) from petrogenic and pyrogenic sources. A range of conjugated oxidation products from petrogenic PAHs are normally accumulated in the bile. Therefore their detection is important. In the present study, phenanthrene and naphthalene metabolites, formed in vivo in Atlantic cod (Gadus morhua), were used to study the response of these compounds in both FF and SFS analyses. The selected synthetic metabolites were (-)-(1R,2R)-1,2-dihydrophenanthrene-1,2-diol and (-)-(1R,2R)-1,2-dihydronaphthalene-1,2-diol. The study findings showed that the recommended excitation and emission wavelengths for FF analysis do not comprise the maximum emission wavelengths for these metabolites, providing an incorrect estimation of the PAH exposure. A method developed in our laboratory for the synthesis of (-)-(1R,2R)-1,2-dihydrophenanthrene-1,2-diol is also described. PMID:26492423

  2. A novel approach for apportionment between primary and secondary sources of airborne nitrated polycyclic aromatic hydrocarbons (NPAHs)

    Science.gov (United States)

    Lin, Yan; Qiu, Xinghua; Ma, Yiqiu; Wang, Junxia; Wu, Yusheng; Zeng, Limin; Hu, Min; Zhu, Tong; Zhu, Yifang

    2016-08-01

    Nitrated polycyclic aromatic hydrocarbons (NPAHs) are strong environmental mutagens and carcinogens originating from both primary emissions and secondary reactions in the atmosphere. The sources and the toxicity of different NPAH species could vary greatly; therefore a specie-specific source apportionment is essential to evaluate their health risks and to formulate controlling regulations. However, few studies have reported source apportionment of NPAHs species to date. In this study, we developed an easy-to-perform method for the apportionment of primary versus secondary sources of airborne NPAHs based on the relationship between NPAHs and NO2. After log-transformation of both NPAHs and NO2 concentrations, a slope of β between these two variables was obtained by the linear regression. When β is significantly smaller than 1, it indicates primary emissions while β significantly greater than 1 suggests secondary formation. We have validated this method with data previously collected in Beijing. A good correlation, with R value of 0.57, was observed between results produced by this new method and by Positive Matrix Factorization (PMF). The correlation could be further improved (R = 0.71) if the gas/particle partition of NPAHs is taken into consideration. This developed method enables the source apportionment for individual NPAHs species and could be used to validate the results of other receptor models.

  3. [Study on degradation of polycyclic aromatic hydrocarbons (PAHs) with different additional carbon sources in aged contaminated soil].

    Science.gov (United States)

    Yin, Chun-Qin; Jiang, Xin; Wang, Fang; Wang, Cong-Ying

    2012-02-01

    This study was conducted with different additional carbon sources (such as: glucose, DL-malic acid, citrate, urea and ammonium acetate) to elucidate the degradation of polycyclic aromatic hydrocarbons (PAHs) in aged contaminated soil under an indoor simulation experiment. The results showed that the quantity of CO2 emission in different additional carbon sources treatments was obviously much more than that of check treatment in the first week, and the quantity of CO2 emission in DL-malic acid treatment was the largest. The average CO2 production decreased in an order urea > glucose approximately citrate approximately DL-malic acid approximately ammonium acetate > check. Meanwhile, the amount of volatized PAHs in applied carbon sources treatments was significantly less than that in check treatment. The amount of three volatized PAHs decreased in an order phenanthrene > fluoranthene > benzo(b)fluoranthene. Compared with the check treatment, the average degradation rates of the three PAHs were significantly augmented in the supplied carbon sources treatments, in which rates of the three PAHs were much higher in DL-malic acid and urea treatments than those in other treatments. The largest proportion of residual was benzo(b)fluoranthene (from 72% to 81%) among three PAHs compounds, followed by fluoranthene (from 53% to 70% ) and phenanthrene (from 27% to 44%).

  4. Source apportionment of the carcinogenic potential of polycyclic aromatic hydrocarbons (PAH) associated to airborne PM10 by a PMF model.

    Science.gov (United States)

    Callén, M S; Iturmendi, A; López, J M; Mastral, A M

    2014-02-01

    In order to perform a study of the carcinogenic potential of polycyclic aromatic hydrocarbons (PAH), benzo(a)pyrene equivalent (BaP-eq) concentration was calculated and modelled by a receptor model based on positive matrix factorization (PMF). Nineteen PAH associated to airborne PM10 of Zaragoza, Spain, were quantified during the sampling period 2001-2009 and used as potential variables by the PMF model. Afterwards, multiple linear regression analysis was used to quantify the potential sources of BaP-eq. Five sources were obtained as the optimal solution and vehicular emission was identified as the main carcinogenic source (35 %) followed by heavy-duty vehicles (28 %), light-oil combustion (18 %), natural gas (10 %) and coal combustion (9 %). Two of the most prevailing directions contributing to this carcinogenic character were the NE and N directions associated with a highway, industrial parks and a paper factory. The lifetime lung cancer risk exceeded the unit risk of 8.7 x 10(-5) per ng/m(3) BaP in both winter and autumn seasons and the most contributing source was the vehicular emission factor becoming an important issue in control strategies. PMID:24022101

  5. Methylated and unsubstituted polycyclic aromatic hydrocarbons in street dust from Vietnam and India: occurrence, distribution and in vitro toxicity evaluation.

    Science.gov (United States)

    Tuyen, Le Huu; Tue, Nguyen Minh; Takahashi, Shin; Suzuki, Go; Viet, Pham Hung; Subramanian, Annamalai; Bulbule, Kesav A; Parthasarathy, Peethambaram; Ramanathan, Alagappan; Tanabe, Shinsuke

    2014-11-01

    Methylated polycyclic aromatic hydrocarbons (MePAHs), unsubstituted PAHs and AhR-mediated activities were determined in street dust collected from Vietnam and India using a combined approach of chemical analysis and in vitro reporter gene assay. MePAHs and PAHs diagnostic ratios indicated that the main sources of MePAHs in Vietnam were pyrogenic emissions, whereas in India there were mixed sources of pyrogenic and petrogenic emissions. AhR-mediated activities determined by using DR-CALUX assay were observed in urban street dust at mean 40, 29 and 20 ng CALUX-TEQ/g dw for Hanoi, Bangalore and New Delhi, respectively. MePAHs and PAHs contributed only 5% or less to AhR-mediated activity in street dust, indicating the occurrence of unknown AhR agonists. The principal contributors to Theoretical-TEQs among target compounds were methyl benz[a]anthracene, benzo[b]- and benzo[k]fluoranthene. The present study indicates importance of MePAHs in evaluation of toxic risk related to AhR-mediated activity in urban polluted areas.

  6. Dispersion modeling of polycyclic aromatic hydrocarbons from combustion of biomass and fossil fuels and production of coke in Tianjin, China.

    Science.gov (United States)

    Tao, Shu; Li, Xinrong; Yang, Yu; Coveney, Raymond M; Lu, Xiaoxia; Chen, Haitao; Shen, Weiran

    2006-08-01

    A USEPA, procedure, ISCLT3 (Industrial Source Complex Long-Term), was applied to model the spatial distribution of polycyclic aromatic hydrocarbons (PAHs) emitted from various sources including coal, petroleum, natural gas, and biomass into the atmosphere of Tianjin, China. Benzo[a]pyrene equivalent concentrations (BaPeq) were calculated for risk assessment. Model results were provisionally validated for concentrations and profiles based on the observed data at two monitoring stations. The dominant emission sources in the area were domestic coal combustion, coke production, and biomass burning. Mainly because of the difference in the emission heights, the contributions of various sources to the average concentrations at receptors differ from proportions emitted. The shares of domestic coal increased from approximately 43% at the sources to 56% at the receptors, while the contributions of coking industry decreased from approximately 23% at the sources to 7% at the receptors. The spatial distributions of gaseous and particulate PAHs were similar, with higher concentrations occurring within urban districts because of domestic coal combustion. With relatively smaller contributions, the other minor sources had limited influences on the overall spatial distribution. The calculated average BaPeq value in air was 2.54 +/- 2.87 ng/m3 on an annual basis. Although only 2.3% of the area in Tianjin exceeded the national standard of 10 ng/m3, 41% of the entire population lives within this area.

  7. Does glucose enhance the formation of nitrogen containing polycyclic aromatic compounds and polycyclic aromatic hydrocarbons in the pyrolysis of proline?

    Energy Technology Data Exchange (ETDEWEB)

    Phillip F. Britt; A.C. Buchanan; Clyde V. Owens, Jr.; J. Todd Skeen [Oak Ridge National Laboratory, Oak Ridge, TN (United States). Chemical and Analytical Sciences Division

    2004-08-01

    The gas-phase pyrolysis of proline, glucose, 1-((2{prime}-carboxy)pyrrolidinyl)-1-deoxy-D-fructose (the proline Amadori compound), and a 1:1 mixture by weight of proline and glucose was investigated at high temperatures (600-840{sup o}C) and short residence time (i.e. 1.0 s) in an inert atmosphere to determine if glucose or Maillard reaction products enhance the formation of nitrogen containing polycyclic aromatic compounds (N-PACs) and polycyclic aromatic hydrocarbons (PAHs) in the pyrolysis of proline. To study the gas-phase formation of N-PACs and PAHs, the substrates were sublimed into the pyrolysis furnace at 460{sup o}C. Thermogravimetric analysis showed that glucose, the proline/glucose mixture, and the proline Amadori compound undergo solid-state decomposition reactions before subliming. Thus, the substrates were pyrolyzed in two stages: at 460{sup o}C during the sublimation and at 600-840{sup o}C. At 800{sup o}C with a residence time of 1.0 s, proline produced low yields of N-PACs, such as quinoline, isoquinoline, indole, acridine, and carbazole, and PAHs, such as phenanthrene, pyrene, benz(a)anthracene, benzofluoranthene isomers, and benzo(a)pyrene. Increasing the temperature and residence time increased the yield of these products. Under similar pyrolysis conditions, the proline Amadori compound produced 2-8 fold more N-PACs and PAHs than proline. A 1:1 mixture of proline and glucose produced a similar slate of pyrolysis products as the proline Amadori compound, but it is unclear whether the proline Amadori compound was an intermediate in the reaction. In general, the proline Amadori compound produced a higher yield of N-PACs and PAHs than the proline/glucose mixture, but glucose clearly enhances the low temperature gas-phase formation of N-PACs and PAHs from the pyrolysis of proline. 56 refs., 10 figs., 3 tabs.

  8. Understanding Polycyclic Aromatic Hydrocarbon transfers at the catchment scale combining chemical and fallout radionuclide analyses

    Science.gov (United States)

    Gateuille, D.; Evrard, O.; Lefevre, I.; Moreau-Guigon, E.; Alliot, F.; Chevreuil, M.; Mouchel, J.-M.

    2012-04-01

    Reducing environmental contamination constitutes a major challenge for industrialized countries. Furthermore, in the European Union, Water Framework Directive (WFD; Directive 2000/60/EC) requires that the member state water bodies reach good ecological and chemical status by 2015. Polycyclic Aromatic Hydrocarbons (PAHs) are a group of persistent organic pollutants considered as priority pollutants because of their mutagenic and carcinogenic properties. They are mostly emitted by human activities such as household heating or road traffic. Although emissions have decreased during the last decades, a large amount of PAHs have been released into the atmosphere for the last two centuries. In recent years, studies dealing with PAHs have grown in number but most of them were restricted to the measurement of PAHs concentrations in the different compartments of the environment (air, soil, sediment, water, etc.). In this context, there remains a lack of knowledge about the transfers and, consequently, about the persistence of these compounds in the environment. This question is particularly acute in the Seine River basin where very high concentrations in PAHs are reported in sediment, thereby compromising the achievement of the good chemical status required by WFD. Our study aims to quantify PAHs transfers at the catchment scale by combining chemical analysis with gamma spectrometry. Atmospheric fallout, soil, river water and sediment samples were collected in two upstream sub-catchments of the Seine River basin during one year. Chemical analyses, restricted to 15 of the 16 PAHs selected by the US Environmental Protection Agency (USEPA), were carried out to determine PAHs concentrations in all samples. Contamination spectra were used to outline the potential origin of pollution. Measurement of fallout radionuclides (Beryllium-7, Lead-210, Caesium-137) in both rainfall and river sediment provided a way to discriminate between freshly eroded sediment vs. material that

  9. Study of the interaction between water and hydrogen sulfide with polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Cabaleiro-Lago, Enrique M; Carrazana-García, Jorge A; Rodríguez-Otero, Jesús

    2009-06-21

    A computational study has been carried out for determining the characteristics of the interaction between one water and hydrogen sulfide molecule with a series of polycyclic aromatic hydrocarbons of increasing size, namely, benzene, anthracene, triphenylene, coronene, circumcoronene, and dicircumcoronene. Potential energy curves were calculated for structures where H(2)X (X=O,S) molecule is located over the central six-membered ring with its hydrogen atoms pointing toward to (mode A) or away from (mode B) the hydrocarbon. The accuracy of different methods has been tested against the results of coupled cluster calculations extrapolated to basis set limit for the smaller hydrocarbons. The spin component scaled MP2 (SCS-MP2) method and a density functional theory method empirically corrected for dispersion (DFT-D) reproduce fairly well the results of high level calculations and therefore were employed for studying the larger systems, though DFT-D seems to underestimate the interaction in hydrogen sulfide clusters. Water complexes in mode A have interaction energies that hardly change with the size of the hydrocarbon due to compensation between the increase in the correlation contribution to the interaction energy and the increase in the repulsive character of the Hartree-Fock energy. For all the other clusters studied, there is a continuous increase in the intensity of the interaction as the size of the hydrocarbon increases, suggesting already converged values for circumcoronene. The interaction energy for water clusters extrapolated to an infinite number of carbon atoms amounts to -13.0 and -15.8 kJ/mol with SCS-MP2 and DFT-D, respectively. Hydrogen sulfide interacts more strongly than water with the hydrocarbons studied, leading to a limiting value of -21.7 kJ/mol with the SCS-MP2 method. Also, complexes in mode B are less stable than the corresponding A structures, with interaction energies amounting to -8.2 and -18.2 kJ/mol for water and hydrogen sulfide

  10. Distribution of Polycyclic aromatic hydrocarbons between water, sediment and common eels (Anguilla angillae) in the urban stretch of Tevere River

    International Nuclear Information System (INIS)

    The research has focused the attention on the occurrence of polycyclic aromatic hydrocarbons (PAHs) in water, sediment and common eels (Angilla anguillae) in the urban area of Tevere River. These compounds can derived from point (E.g.oil spill) or non-point (e.g. atmospheric deposition) sources and are one of the most widespread organic pollutants. (Author)

  11. Analysis of polycyclic aromatic hydrocarbons. I. Determination by gas chromatography with glass and fused solica capillary columns

    International Nuclear Information System (INIS)

    A study of the analysis by gas chromatography of aromatic polycyclic hydrocarbons is presented. The separation has been carried out by glass and fused silice capillary column. The limitations and the advantages of the procedure are discussed in terms of separation efficiency, sensitivity and precision. (author). 3 figs., 17 refs

  12. Analysis of polycyclic aromatic hydrocarbons I. Determination by gas chromatography with glass and fused silica capillary columns

    International Nuclear Information System (INIS)

    A study of the analysis by gas chromatography of aromatic polycyclic hydrocarbons is presented. The separation has been carried out by glass and fused silica capillary column. The limitations and the advantages of the procedure are discussed in terms of separation efficiency, sensitivity and precision. (Author) 17 refs

  13. Repair of DNA damage induced by anthanthrene, a polycyclic aromatic hydrocarbon (PAH) without bay or fjord regions

    DEFF Research Database (Denmark)

    Madsen, Claus Desler; Johannessen, Christian; Rasmussen, Lene Juel

    2009-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are environmental pollutants, formed during incomplete burning of coal, oil and gas. Several PAHs have carcinogenic and mutagenic potencies, but these compounds must be activated in order to exert their mutagenic effects. One of the principal pathways...

  14. Breast cancer and urinary biomarkers of polycyclic aromatic hydrocarbon and oxidative stress in the Shanghai Women’s Health Study

    OpenAIRE

    Lee, Kyoung-Ho; Shu, Xiao-Ou; Gao, Yu-Tang; Ji, Bu-Tian; YANG, Gong; Blair, Aaron; Rothman, Nathaniel; Zheng, Wei; Chow, Wong-Ho; Kang, Daehee

    2010-01-01

    Polycyclic aromatic hydrocarbon (PAH) exposures and oxidative stress from such and other exposures have been associated with breast cancer in some studies. To further evaluate the role of PAH metabolites and oxidative stress on the development of breast cancer, we conducted a nested case-control study in the Shanghai Women’s Health Study (SWHS).

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

    NARCIS (Netherlands)

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

    2011-01-01

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

  16. Novel magnetic nanoparticles coated by benzene- and β-cyclodextrin-bearing dextran, and the sorption of polycyclic aromatic hydrocarbon

    DEFF Research Database (Denmark)

    Cho, Eunae; Tahir, Muhammad Nazir; Min Choi, Jae;

    2015-01-01

    , the potential for removing polycyclic aromatic hydrocarbons such as phenanthrene and pyrene by sorption onto the nanomaterials was assessed. In the sorption, pi-stacking interactions of the benzene-derivatized dextran and host–guest chemistry of the β-cyclodextrin-derivatized dextran were considered...

  17. The occupational exposure of dermatology nurses to polycyclic aromatic hydrocarbons - evaluating the effectiveness of better skin protection.

    NARCIS (Netherlands)

    Scheepers, P.T.J.; Houtum, J.L.M. van; Anzion, R.B.M.; Champmartin, C.; Hertsenberg, S.; Bos, R.P.; Valk, P. van der

    2009-01-01

    OBJECTIVES: We studied the uptake of polycyclic aromatic hydrocarbons (PAH) in nurses who apply ointments containing coal tar to patients and investigated the effectiveness of skin protection methods. METHODS: We determined gas-phase PAH on XAD-2 and particle-associated PAH on filters. We also used

  18. Theory and application of landfarming to remediate polycyclic aromatic hydrocarbons and mineral oil-contaminated sediments: beneficial reuse

    NARCIS (Netherlands)

    Harmsen, J.; Rulkens, W.H.; Sims, R.C.; Rijtema, P.E.; Zweers, A.J.

    2007-01-01

    When applying landfarming for the remediation of contaminated soil and sediment, a fraction of the soil-bound contaminant is rapidly degraded; however, a residual concentration may remain, which slowly degrades. Degradation of polycyclic aromatic hydrocarbons (PAHs) and mineral oil can be described

  19. Impact of polychlorinated biphenyl and polycyclic aromatic hydrocarbon sequestration in sediment on bioaccumulation in aquatic food webs

    NARCIS (Netherlands)

    Moermond, C.T.A.; Roessink, I.; Jonker, M.T.O.; Meijer, T.; Koelmans, A.A.

    2007-01-01

    It is not clear whether sequestration or aging of organic chemicals like polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) limits accumulation in higher levels of aquatic food chains. Therefore, the effect of aging on accumulation was studied in 1-m3 model ecosystems that

  20. THE PENALIZED OPTIMAL EXPERIMENTAL DESIGN: THE PRECISE ESTIMATION OF AN INTERACTION THRESHOLD IN A MIXTURE OF EIGHTEEN POLYHALOGENATED AROMATIC HYDROCARBONS.

    Science.gov (United States)

    Crofton et al. (EHP, 2005) conducted a study of 18 polyhalogenated aromatic hydrocarbons (PHAHs) on serum total thyroxine (T4). Young female Long-Evans rats were dosed with the 18 single agents or a fixed-ratio mixture, and serum total T4 was measured via radioimmunoassay. The i...

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

    DEFF Research Database (Denmark)

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

    2010-01-01

    smoking, and for other fish species direct smoking leads to higher sigma PAH25 than indirect smoking. Also, the usage of common alder increases the PAH contamination compared with beech. The effects of smoking time, combustion temperatures, and two types of smoke-generating material on the Sigma PAH25......A new method for the analysis of 25 polycyclic aromatic hydrocarbon (PAH) compounds in fish was developed, validated, and used for the quantification of PAHs in 180 industrially smoked fish products. The method included pressurized liquid extraction, gel-permeation chromatography (Bio-beads S-X3...... concentrations were obtained for indirectly smoked trout (26 mu g kg-1). Principal component analysis was used to correlate processing parameters to PAH concentrations and to identify the effects of these parameters. The analysis showed that for salmon hot-smoking conditions lead to higher sigma PAH25 than cold...

  2. Microbial degradation of street dust polycyclic aromatic hydrocarbons in microcosms simulating diffuse pollution of urban soil

    DEFF Research Database (Denmark)

    Johnsen, Anders R; de Lipthay, Julia R; Sørensen, Søren J;

    2006-01-01

    Diffuse pollution with polycyclic aromatic hydrocarbons (PAHs) of topsoil in urban regions has caused increasing concerns in recent years. We simulated diffuse pollution of soil in microcosms by spiking sandy topsoil (A-horizon) and coarse, mineral subsoil (C-horizon) with street dust (PM63......) isolated from municipal street sweepings from central Copenhagen. The microbial communities adapted to PAH degradation in microcosms spiked with street dust in both A-horizon and C-horizon soils, in spite of low PAH-concentrations. The increased potential for PAH degradation was demonstrated on several...... levels: by slowly diminishing PAH-concentrations, increased mineralization of 14C-PAHs, increasing numbers of PAH degraders and increased prevalence of nah and pdo1 PAH degradation genes, i.e. the microbial communities quickly adapted to PAH degradation. Three- and 4-ring PAHs from the street dust were...

  3. Overview of established and emerging treatment technologies for polycyclic aromatic hydrocarbons at wood preserving facilities

    International Nuclear Information System (INIS)

    The contamination of soil and groundwater by polycyclic aromatic hydrocarbons (PAHs) is common to wood preserving facilities and manufactured gas plants. Since the inception of RCRA and CERCLA, much attention has been focused upon the remediation of both active and defunct wood preserving facilities. The experiences gleaned from the use of proven technologies, and more importantly, the lessons being learned in the trials of emerging technologies on creosote-derived PAH clean-ups at wood preserving sites, should have direct bearing on the clean-up of similar contaminants at MGP sites. In this paper, a review of several remedial actions using waste removal/disposal, on-site incineration, and bioremediation will be presented. Additionally, emerging technologies for the treatment of PAH-contaminated soil and water will be reviewed. Lastly, recent information on risk assessment results for creosote sites and treated PAH waste will be discussed

  4. Source apportionment of polycyclic aromatic hydrocarbons (PAHs) in sediments from Khuzestan province, Iran

    DEFF Research Database (Denmark)

    Lübeck, Josephine; Poulsen, Kristoffer Gulmark; Knudsen, Sofie B.;

    2016-01-01

    Khuzestan, Iran is heavily industrialised with petrochemical and refinery companies. Herein, sediment and soil samples were collected from Hendijan coast, Khore Mosa and Arvandroud River. The CHEMSIC (CHEmometric analysis of Selected Ion Chromatograms) method was used to assign the main sources...... of polycyclic aromatic hydrocarbon (PAH) pollution. A four-component principal component analysis (PCA) model was obtained. While principal component 1 (PC1) was related to the total concentration of PAHs, the remaining PCs described three distinct sources: PC2 and PC3 collectively differentiate between...... weathered petrogenic and pyrogenic, and PC4 is indicative for a diagenetic input. The sources of PAHs in the Arvandroud River were mainly relatively fresh oil with some samples corresponding to a weathered oil input. Further, perylene (indicator for diagenetic source) was identified. Samples from Khore Mosa...

  5. Role of volcanic dust in the atmospheric transport and deposition of polycyclic aromatic hydrocarbons and mercury.

    Science.gov (United States)

    Stracquadanio, Milena; Dinelli, Enrico; Trombini, Claudio

    2003-12-01

    The role of volcanic ash as scavenger of atmospheric pollutants, in their transport and final deposition to the ground is examined. Attention is focused on polycyclic aromatic hydrocarbons (PAHs) and on particulate mercury (Hgp). The ash-fall deposits studied belong to the 2001 and 2002 eruptive activity of Mount Etna, Southern Italy, and were investigated at three (2001) and four (2002) sites downwind of the major tephra dispersal pattern. The dry deposition of mercury and PAHs was determined, and, in particular, a downward flux to the ground of PAHs (approximately 7.29 microg m(-2) per day) and mercury (750 ng m(-2) per day) was estimated in Catania from October 26 to October 28, 2002. Finally, evidence on the anthropogenic origin of PAHs scavenged from the troposphere by volcanic ash is supported by the analysis of PAH compositions in granulometrically homogeneous fractions.

  6. Biotransformation of the polycyclic aromatic hydrocarbon pyrene in the marine polychaete Nereis virens

    DEFF Research Database (Denmark)

    Jørgensen, Anne; Glessing, Anders M B; Rasmussen, Lene Juel;

    2005-01-01

    In vivo and in vitro biotransformation of the polycyclic aromatic hydrocarbon (PAH) pyrene was investigated in the marine polychaete Nereis virens. Assays were designed to characterize phase I and II enzymes isolated from gut tissue. High-pressure liquid chromatography measurement of 1......-hydroxypyrene, pyrene-1-glucuronide, pyrene-1-sulfate, and pyrene-1-glucoside appeared to be a sensitive method for estimating the activity of pyrene hydroxylase, glucuronosyl transferase, and sulfotransferase. Total pyrene in gut tissue after a 5-d exposure to 10 microg/g dry weight pyrene constituted 65....... Apparent kinetic parameters for pyrene hydroxylase activity were changed after induction with pyrene. Induced worms showed increased Vmax(a)) and decreased Km(a) compared to noninduced worms, indicating that the relative amount of the cytochrome P450 enzyme(s) responsible for pyrene hydroxylation...

  7. Polycyclic aromatic hydrocarbons alter the structure of oceanic and oligotrophic microbial food webs

    KAUST Repository

    Cerezo, Maria Isabel

    2015-11-01

    One way organic pollutants reach remote oceanic regions is by atmospheric transport. During the Malaspina-2010 expedition, across the Atlantic, Indian, and Pacific Oceans, we analyzed the polycyclic aromatic hydrocarbon (PAH) effects on oceanic microbial food webs. We performed perturbation experiments adding PAHs to classic dilution experiments. The phytoplankton growth rates were reduced by more than 5 times, being Prochlorococcus spp. the most affected. 62% of the experiments showed a reduction in the grazing rates due to the presence of PAHs. For the remaining experiments, grazing usually increased likely due to cascading effects. We identified changes in the slope of the relation between the growth rate and the dilution fraction induced by the pollutants, moving from no grazing to V-shape, or to negative slope, indicative of grazing increase by cascade effects and alterations of the grazers\\' activity structure. Our perturbation experiments indicate that PAHs could influence the structure oceanic food-webs structure.

  8. Variability of Biological Degradation of Aromatic Hydrocarbons in an Aerobic Aquifer Determined by Laboratory Batch Experiments

    DEFF Research Database (Denmark)

    Nielsen, Per Henning; Christensen, Thomas Højlund

    1994-01-01

    The biological aerobic degradation of 7 aromatic hydrocarbons (benzene, toluene, o-xylene, p-dichlorobenzene, o-dichlorobenzene, naphthalene and biphenyl) was studied for 149 days in replicate laboratory batch experiments with groundwater and sediment from 8 localities representing a 15 m × 30 m...... section of an aerobic aquifer. Compared to biologically deactivated control experiments all compounds were biologically degraded. Degradation curves were very reproducible for some compounds (benzene, toluene, o-xylene, o-dichlorobenzene and p-dichlorobenzene) and less reproducible for other (naphthalene...... and biphenyl). Based on observed length of lag phases, length of the degradation periods and percent degradation, the variation among the 8 localities appears to be modest. However, detailed examination of the degradation rates revealed statistically significant variation among localities for benzene, toluene...

  9. [Assessment of exposure to cancerogenic aromatic hydrocarbon during controlled-access highways management activities].

    Science.gov (United States)

    Martinotti, I; Cirla, A M; Cottica, D; Cirla, P E

    2011-01-01

    The purpose of this study was an integrated assessment of exposure to benzene and Polycyclic Aromatic Hydrocarbons (PAH) in 29 workers employed to manage a controlled-access highways. A campaign was performed in summertime by environmental monitoring (active and passive airborne personal sampler), as well as by biological monitoring (urine samples of the beginning and of the end of daily shift, baseline after two days of vacation). The measured environmental levels did not differ from background environmental concentrations found in a metropolitan area (i.e. benzo[a]pyrene < 1 ng/m3; benzene < 5 mcg/m3), and the results of biological monitoring were in agreement and were compatible with extra-professional habits of the investigated subjects (1-hydroxipyrene 50-990 ng/g creatinine; unmetabolized benzene 15-2010 ng/I; t-t muconic acid < 4-222 mcg/g creatinine).

  10. Trapping of polycyclic aromatic hydrocarbons by amphiphilic cyclodextrin functionalized polypropylene nonwovens

    DEFF Research Database (Denmark)

    Lumholdt, Ludmilla; Nielsen, Ronnie Bo Højstrup; Larsen, Kim Lambertsen

    Recently, there has been an augmented focus on the increasing amount of pesticides, drug residues and endocrine disruptors present in waste and drinking water1. These pollutants represent a challenge in water purification since they may be hazardous to human health even in low doses2. Cyclodextrins...... of the textile fibers. In this study we present the ability of amphiphilic CD coated polypropylene nonwovens to trap 8 different polycyclic aromatic hydrocarbons/endocrine disruptors from aqueous solutions thus demonstrating the potential of using the amphiphilic cyclodextrins for water purification....... (CDs) are known to be able to form inclusion complexes with a large range of the unwanted pollutantse.g. 3 but in order to utilise this ability to purify water, the CDs must be immobilised on a surface, for instance, a membrane filter. We have developed a simple and fast method...

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

    International Nuclear Information System (INIS)

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

  12. Use of antioxidant enzymes of clam Ruditapes philippinarum as biomarker to polycyclic aromatic hydrocarbon pollution

    Science.gov (United States)

    Zhu, Lin; Tang, Xuexi; Wang, Ying; Sui, Yadong; Xiao, Hui

    2016-03-01

    The typical organic pollutant polycyclic aromatic hydrocarbon (PAH) anthracene was selected as a contaminant to investigate its effects on the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) in the clam Ruditapes philippinarum. The results show that SOD, CAT and GSH-Px had diff erent induction and inhibition reactions to anthracene stress, and that three diff erent organs in R. philippinarum (visceral mass, muscle tissue and mantle) had diff erent sensitivities to anthracene stress. This study suggest that SOD activities of the visceral mass, CAT activitities of the mantle and the visceral mass, and GSH-Px activity of the muscle tissue could be used as sensitive indicators of anthracene stress in R. philippinarum.

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

    Science.gov (United States)

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

    2014-01-01

    Polycyclic aromatic hydrocarbons (PAHs) in soil have been recognised as a serious health and environmental issue due to their carcinogenic, mutagenic and teratogenic properties. One of the commonly employed soil remediation techniques to clean up such contamination is soil washing or solvent extraction. The main factor which governs the efficiency of this process is the solubility of PAHs in the extraction agent. Past field-scale soil washing treatments for PAH-contaminated soil have mainly employed organic solvents or water which is either toxic and costly or inefficient in removing higher molecular weight PAHs. Thus, the present article aims to provide a review and discussion of the alternative extraction agents that have been studied, including surfactants, biosurfactants, microemulsions, natural surfactants, cyclodextrins, vegetable oil and solution with solid phase particles. These extraction agents have been found to remove PAHs from soil at percentages ranging from 47 to 100% for various PAHs. PMID:24100092

  14. Study on Removing Trace Olefins in Aromatic Hydrocarbons with HPMo-loaded Y Zeolites

    Institute of Scientific and Technical Information of China (English)

    Jiang Zhenghong; Zeng Haiping; Shi Li

    2008-01-01

    HPMo-loaded Y-zeolites were prepared for the removal of trace olefins from aromatic hydrocarbons.The temperature of calcination and the proportion of phospho-molybdic acid in the catalyst were studied. The catalytic activity for olefins removal and the service life of the catalyst were tested in a fixed bed microreactor. The results showed that the catalyst containing 3% phospho-molybdic acid, which was calcined at 550℃,demonstrated the best activity for olefins removal. The catalyst could be regenerated and could perform still very well. Catalyst characterization was performed by XRD and measured by pyridine-FTIR spectrometry. The test results indicated that the activity of the catalyst was related with the effect of acid concentration and acid strength. Besides, the deactivation of the catalyst was associated with the formation of coke deposits and the deactivated catalyst could recover its activity by oxidation with air under a proper temperature.

  15. Qualitative TLC determination of some polycyclic aromatic hydrocarbons in sugar-beet

    Directory of Open Access Journals (Sweden)

    BILJANA D. SKRBIC

    2005-10-01

    Full Text Available The presence of polycyclic or polynuclear aromatic hydrocarbons (PAHs were investigated in sugar-beet from a local sugar factory in the district of Vojvodina. The sugar-beet was cultivated on areas near roads with intensive traffic. The procedure for the preparation and determination of these compounds included saponification of the sample, several liquid–liquid extraction systems and a silica gel column clean-up. The purified sample solution was analysed by thin layer chromatography (TLC on silica gel with cyclohexane as the developing solvent. Benzo(bfluoranthene and benzo(aanthracene and/or benzo(apyrene were detected at concentrations greater than the allowed limits in food.

  16. Enhanced diffusion of polycyclic aromatic hydrocarbons in artificial and natural aqueous solutions

    DEFF Research Database (Denmark)

    Mayer, Philipp; Fernqvist, M.M.; Christensen, P.S.;

    2007-01-01

    Uptake of hydrophobic organic compounds into organisms is often limited by the diffusive transport through a thin boundary layer. Therefore, a microscale diffusion technique was applied to determine the diffusive mass transfer of 12 polycyclic aromatic hydrocarbons through water, air, surfactant...... solutions, humic acid solutions, aqueous soil and horse manure extracts, digestive fluid of a deposit-feeding worm, and root exudates from willow plants. In most cases the diffusive mass transfer of PAHs was much higher through the tested media than through water, and the enhancement factors increased...... with increasing hydrophobicity of the PAHs. The diffusive flux of benzo[a]pyrene was for instance enhanced 74 times through gut fluid of a deposit-feeding worm when compared to water. These findings demonstrate that a wide variety of dissolved organic carbon (DOC) at environmental levels can enhance diffusive...

  17. On-line database of the spectral properties of polycyclic aromatic hydrocarbons

    CERN Document Server

    Malloci, G; Mulas, G; 10.1016/j.chemphys.2007.01.001

    2009-01-01

    We present an on-line database of computed molecular properties for a large sample of polycyclic aromatic hydrocarbons (PAHs) in four charge states: -1, 0, +1, and +2. At present our database includes 40 molecules ranging in size from naphthalene and azulene (C10H8) up to circumovalene (C66H20). We performed our calculations in the framework of the density functional theory (DFT) and the time-dependent DFT to obtain the most relevant molecular parameters needed for astrophysical applications. For each molecule in the sample, our database presents in a uniform way the energetic, rotational, vibrational, and electronic properties. It is freely accessible on the web at http://astrochemistry.ca.astro.it/database/ and http://www.cesr.fr/~joblin/database/.

  18. Polycyclic aromatic hydrocarbons in blood related to lower body mass in common loons.

    Science.gov (United States)

    Paruk, James D; Adams, Evan M; Uher-Koch, Hannah; Kovach, Kristin A; Long, Darwin; Perkins, Christopher; Schoch, Nina; Evers, David C

    2016-09-15

    We captured 93 wintering adult and subadult Common Loons (Gavia immer) in coastal Louisiana from 2011 to 2015 following the Deepwater Horizon oil spill. We tested blood samples for exposure to polycyclic aromatic hydrocarbons (PAHs) and measured physiological variables including hematocrit, hemoglobin and total blood protein. PAH concentrations in loon blood differed from year to year and by age class. High PAH concentrations were significantly related to lower body masses in both adult and subadult birds and higher serum protein levels in adults only. PAH concentrations had marginal relations with both hematocrit and hemoglobin levels. The types of PAHs detected also underwent a major shift over time. The PAHs detected in 2011, 2012, and 2015 were primarily low molecular weight (three carbon rings); however, in 2013, most detected PAHs were high molecular weight (four carbon rings). It is unclear what events led to the increase in PAH concentrations and the shift in type of PAHs over time. PMID:27177142

  19. Polycyclic aromatic hydrocarbons and total extractable particulate organic matter in the Arctic aerosol

    International Nuclear Information System (INIS)

    Samples of total suspended particulate matter were collected in March and August 1979 at Barrow, Alaska, a remote site in the Arctic. Ambient concentrations of extractable particulate organic matter (POM), of polycyclic aromatic hydrocarbons (PAH) and of 210Pb were determined. The samples were also examined by optical and scanning electron microscopy. Average concentrations of POM and PAH were similar to those reported for other remote sites in the northern hemisphere, but the concentrations were considerably higher in March than in August. The presence of fly ash in the samples collected during the March sampling period, as well as seasonal differences in the concentrations of the organic species and 210Pb and in meteorology indicate that the principal source of POM and PAH was fossil fuel combustion in the mid-latitudes during the March sampling period. (author)

  20. Compost-mediated removal of polycyclic aromatic hydrocarbons from contaminated soil.

    Science.gov (United States)

    Sasek, V; Bhatt, M; Cajthaml, T; Malachová, K; Lednická, D

    2003-04-01

    Compost-assisted remediation of a manufactured-gas plant soil contaminated with polycyclic aromatic hydrocarbons (PAHs) was performed in thermally insulated composting chamber using mushroom compost consisting wheat straw, chicken manure, and gypsum. The degradation of individual PAHs was in range of 20-60% at the end of 54 days of composting followed by further increase of PAH removal (37-80%) after another 100 days of maturation. Both chemical analysis of the contaminated soil for PAHs and ecotoxicity tests on bioluminescent bacteria, earthworms, and plant seeds were performed before and after the composting. After the composting, inhibition of bioluminescence decreased, whereas no significant change in toxicity was observed for earthworm survival and seed germination. Using bacterial culture of Escherichia coli K12 genotoxicity tests were performed on samples taken from different parts of the composting pile; after the composting the decrease in genotoxicity was observed only in the sample taken from upper part of the composted pile.

  1. Application of random forests method to predict the retention indices of some polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Goudarzi, N; Shahsavani, D; Emadi-Gandaghi, F; Chamjangali, M Arab

    2014-03-14

    In this work, a quantitative structure-retention relationship (QSRR) investigation was carried out based on the new method of random forests (RF) for prediction of the retention indices (RIs) of some polycyclic aromatic hydrocarbon (PAH) compounds. The RIs of these compounds were calculated using the theoretical descriptors generated from their molecular structures. Effects of the important parameters affecting the ability of the RF prediction power such as the number of trees (nt) and the number of randomly selected variables to split each node (m) were investigated. Optimization of these parameters showed that in the point m=70, nt=460, the RF method can give the best results. Also, performance of the RF model was compared with that of the artificial neural network (ANN) and multiple linear regression (MLR) techniques. The results obtained show the relative superiority of the RF method over the MLR and ANN ones.

  2. Correlation of levels of volatile versus carcinogenic particulate polycyclic aromatic hydrocarbons in air samples from smokehouses

    DEFF Research Database (Denmark)

    Hansen, Åse Marie; Poulsen, O M; Christensen, J M

    1991-01-01

    In the present study, data on the concentration of polycyclic aromatic hydrocarbons (PAH) in air samples from fish smokehouses (Nordholm et al. 1986) and meat smokehouses (Hansen et al. submitted for publication) were used to analyze the extent to which six different volatile PAH compounds could...... carcinogenic PAH compounds in air samples from smokehouses, whereas fluoranthene and pyrene displayed the highest specificity. However, when the applicability of the six markers was tested on air samples from iron foundries, only naphthalene and pyrene were useful as markers for the carcinogenic compounds...... function as markers for the total concentration of six different carcinogenic particulate PAH compounds. Although a significant positive correlation was observed between the concentration of each of six volatile compounds and the total concentration of carcinogenic PAH compounds, a particularly good...

  3. Epigenetic modulation of Chlorella (Chlorella vulgaris) on exposure to polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Yang, Mihi; Youn, Je-In; Kim, Seung Joon; Park, Jong Y

    2015-11-01

    DNA methylation in promoter region can be a new chemopreventive marker against polycyclic aromatic hydrocarbons (PAHs). We performed a randomized, double blind and cross-over trial (N=12 healthy females) to evaluate chlorella (Chlorella vulgaris)-induced epigenetic modulation on exposure to PAHs. The subjects consumed 4 tablets of placebo or chlorella supplement (total chlorophyll ≈ 8.3mg/tablet) three times a day before meals for 2 weeks. When the subjects consumed chlorella, status of global hypermethylation (5-methylcytosine) was reduced, compared to placebo (p=0.04). However, DNA methylation at the DNMT1 or NQO1 was not modified by chlorella. We observed the reduced levels of urinary 1-hydroxypyrene (1-OHP), a typical metabolite of PAHs, by chlorella intake (pchlorella-induced changes in global hypermethylation and urinary 1-OHP (pchlorella works for PAH-detoxification through the epigenetic modulation, the interference of ADME of PAHs and the interaction of mechanisms.

  4. Heavy metals and polycyclic aromatic hydrocarbons in surface sediments of Karoon River, Khuzestan Province, Iran.

    Science.gov (United States)

    Keshavarzi, Behnam; Mokhtarzadeh, Zeinab; Moore, Farid; Rastegari Mehr, Meisam; Lahijanzadeh, Ahmadreza; Rostami, Soqra; Kaabi, Helena

    2015-12-01

    Karoon is the longest river in Iran and provides water for industries located along its banks, such as metal, petrochemical, and oil industries. It is also the source of drinking water for cities such as Ahwas, Abadan, and Khorramshahr. In this study, 34 and 18 surface sediment samples were collected and analyzed for heavy metals (Al, As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) and polycyclic aromatic hydrocarbons (PAHs). The measured concentrations of heavy metals were compared with US EPA sediment quality guidelines, and the results showed that Cu concentration was above the threshold effect level (TEL) in 65.67% of the samples and Hg concentration was above the effect range median (ERM) in some samples. The results revealed that Hg was severely enriched (5 factory and Abadan petrochemical complex. Principal component analysis and cluster analysis also revealed the relationships between the studied parameters and identified their probable sources. PMID:26233736

  5. Extraction of polycyclic aromatic hydrocarbons from smoked fish using pressurized liquid extraction with integrated fat removal

    DEFF Research Database (Denmark)

    Lund, Mette; Duedahl-Olesen, Lene; Christensen, Jan H.

    2009-01-01

    extraction with fat retention in one single analytical step. The PLE parameters: type of fat retainer, flush volume, solvent composition, fat-to-fat retainer ratio (FFR), and the dimensions of the extraction cells were the most important factors for obtaining fat-free extracts with high recoveries of PAHs. A...... 100 mL extraction cell filled with 18 g activated silica gel, dichloromethane:hexane (15:85, v/v) as extraction solvent, FFR of 0.025 and 100% flush volume was the best analytical setup for integrated extraction and fat retention. The one-step procedure provided a more rapid and cost......Quantification of polycyclic aromatic hydrocarbons (PAHs) in smoked fish products often requires multiple clean-up steps to remove fat and other compounds that may interfere with the chemical analysis. We present a novel pressurized liquid extraction (PLE) method that integrates exhaustive...

  6. THE INFRARED SPECTRA OF POLYCYCLIC AROMATIC HYDROCARBONS WITH SOME OR ALL HYDROGEN ATOMS REMOVED

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-10-20

    The loss of one hydrogen from C{sub 96}H{sub 24} does not significantly affect the infrared spectra of the neutral, cation, or anion. Excluding a very weak C-C stretching band at 5.1 μm, the loss of two adjacent duo hydrogens does not significantly affect the spectra compared with the parent. Removing all of the hydrogen atoms significantly increases the intensity of the new C-C stretching band, and, for the cation, shifts it to a longer (5.2 μm) wavelength. Observations show a feature near 5.25 μm, which has been attributed to overtone and combination bands from polycyclic aromatic hydrocarbons (PAHs). This current work suggests that dehydrogenated PAHs might also contribute to this band, but its weakness implies that fully dehydrogenated cationic or dicationic species are very rare.

  7. Problems in the fingerprints based polycyclic aromatic hydrocarbons source apportionment analysis and a practical solution.

    Science.gov (United States)

    Zou, Yonghong; Wang, Lixia; Christensen, Erik R

    2015-10-01

    This work intended to explain the challenges of the fingerprints based source apportionment method for polycyclic aromatic hydrocarbons (PAH) in the aquatic environment, and to illustrate a practical and robust solution. The PAH data detected in the sediment cores from the Illinois River provide the basis of this study. Principal component analysis (PCA) separates PAH compounds into two groups reflecting their possible airborne transport patterns; but it is not able to suggest specific sources. Not all positive matrix factorization (PMF) determined sources are distinguishable due to the variability of source fingerprints. However, they constitute useful suggestions for inputs for a Bayesian chemical mass balance (CMB) analysis. The Bayesian CMB analysis takes into account the measurement errors as well as the variations of source fingerprints, and provides a credible source apportionment. Major PAH sources for Illinois River sediments are traffic (35%), coke oven (24%), coal combustion (18%), and wood combustion (14%). PMID:26208321

  8. Distribution and sources of polycyclic aromatic hydrocarbons (PAHs) in street dust from the Tokyo Metropolitan area.

    Science.gov (United States)

    Takada, H; Onda, T; Harada, M; Ogura, N

    1991-09-01

    Molecular distributions of polycyclic aromatic hydrocarbons (PAHs) in street dust samples collected from the Tokyo Metropolitan area were determined by capillary gas chromatography following HPLC fractionation. Three- to six-ring PAHs and sulfur-heterocyclics were detected. PAHs in the dusts were dominated by three and four unsubstituted ring systems with significant amounts of their alkyl homologues. PAHs were widely distributed in the streets, with concentrations (sigma COMB) of a few microgram/g dust. Automobile exhaust, asphalt, gasoline fuel, diesel fuel, tyre particles, automobile crankcase oils, and atmospheric fallout were also analysed. The PAH profile, especially the relative abundance of alkyl-PAHs and sulfur-containing heterocyclics, indicated that PAHs in the street dusts from roads carrying heavy traffic are mainly derived from automobile exhausts; dusts from residential areas have a more significant contribution from atmospheric fallout.

  9. [Limit values for polycyclic aromatic hydrocarbons in soil of children's playgrounds--basic criteria and recommendations].

    Science.gov (United States)

    Roscher, E; Liebl, B; Schwegler, U; Schmied, R; Kerscher, G

    1996-01-01

    Elevated concentrations of polycyclic aromatic hydrocarbons (PAK) are often found in the soil of former waste disposal sites, industrial areas, etc. It is desirable and useful to determine orientation values to facilitate and unify the evaluation of contaminations under the aspects of present or planned uses of an area, health protection and decision-making on remedial measures. In the present paper we wish to draw attention to, and discuss problems resulting from, particular characteristics of PAK, e.g. the toxicological property "complete carcinogens" or the necessity of taking into account oral, inhalative and dermal exposure of children on a playground. Based on the discussion, orientation values for benzo[a]pyrene and PAK ("normal" pattern) of 0.5 mg/kg soil and 5 mg/kg soil, respectively, are recommended for top soil of vegetation-free playgrounds. In comparison, deductions carried out by other working groups are presented.

  10. A 25-year record of polycyclic aromatic hydrocarbons in soils amended with sewage sludges

    DEFF Research Database (Denmark)

    Lichtfouse, Eric; Sappin-Didier, Valérie; Denaix, Laurence;

    2005-01-01

    We studied polycyclic aromatic hydrocarbons (PAHs) in crop soils amended with 1000 tonnes dry weight of sewage sludges per 10,000 m(2) from 1974 to 1992, then after sludges addition from 1993 to 1999. The absence of variations of total PAHs levels of control soils, averaging at 123 mu g/Kg, shows...... the absence of horizontal contamination. During sludges addition, the total PAHs levels in amended soils increased from 232 to 402 mu g/Kg. Seven years after sludges addition, it decreased to 275 mu g/Kg, which is still more than twice the levels of control soils. This finding shows that sludges PAHs...... are preserved in crop soils for long periods of time, on a human scale....

  11. The phototoxicity of polycyclic aromatic hydrocarbons: a theoretical study of excited states and correlation to experiment.

    Science.gov (United States)

    Betowski, Leon D; Enlow, Mark; Riddick, Lee

    2002-06-01

    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 calculated for ten PAHs by several ab initio methods. The main method used for these calculations was the Configuration Interaction approach, modeling excited states as combinations of single substitutions out of the Hartree-Fock ground state. These calculations correlate well with both experimentally measured singlet and triplet state energies and also previous HOMO-LUMO gap energies that approximate the singlet state energies. The excited state calculations then correlate well with general models of photo-induced toxicity based for the PAHs.

  12. Analysis of carcinogenic Polycyclic Aromatic Hydrocarbons (PAHS): an overview of modern electroanalytical techniques and their applications.

    Science.gov (United States)

    Şentürk, Zühre

    2013-02-01

    A number of Polycyclic Aromatic Hydrocarbons (PAHs) have been shown to be toxicants, and induce carcinogenic and immunotoxic effects. Since PAHs are often present in low concentrations and it may be difficult to determine them in complex matrices, it is therefore essential to use powerful analytical tools to separate and identify the analyses in the samples. In this paper, initially, a short description of the principles, instrumentation, and use of common extraction and analytical techniques for PAH pollutants and their metabolites will be made in light of the previously reported works and major reviews. Special attention will be given to the use of modern polarographic and voltammetric techniques on the mercury and different types of solid electrodes, together with their some practical applications. The main drawbacks and limitations of these methods will also be discussed.

  13. Distribution and sources of polycyclic aromatic hydrocarbons (PAHs) in street dust from the Tokyo Metropolitan area.

    Science.gov (United States)

    Takada, H; Onda, T; Harada, M; Ogura, N

    1991-09-01

    Molecular distributions of polycyclic aromatic hydrocarbons (PAHs) in street dust samples collected from the Tokyo Metropolitan area were determined by capillary gas chromatography following HPLC fractionation. Three- to six-ring PAHs and sulfur-heterocyclics were detected. PAHs in the dusts were dominated by three and four unsubstituted ring systems with significant amounts of their alkyl homologues. PAHs were widely distributed in the streets, with concentrations (sigma COMB) of a few microgram/g dust. Automobile exhaust, asphalt, gasoline fuel, diesel fuel, tyre particles, automobile crankcase oils, and atmospheric fallout were also analysed. The PAH profile, especially the relative abundance of alkyl-PAHs and sulfur-containing heterocyclics, indicated that PAHs in the street dusts from roads carrying heavy traffic are mainly derived from automobile exhausts; dusts from residential areas have a more significant contribution from atmospheric fallout. PMID:1785054

  14. [Symptoms of atopy in persons exposed to chronic immunosuppression of polycyclic aromatic hydrocarbons].

    Science.gov (United States)

    Szczeklik, J; Kowalczyk, E; Gałuszka, Z

    1995-01-01

    The frequency of the atopy symptoms was estimated in 126 coke oven workers chronically exposed to polycyclic aromatic hydrocarbons (PAHs). The assessment was based on questionnaire, point skin tests with the allergens of dust, feathers, mould grass as well as on the measurements of total blood serum IgE concentration. The control group was consisted of 75 men, workers of cold rolling mill division where the environmental conditions were much better. It was observed that positive questionnaire data and positive skin tests were significantly less frequent in men exposed to PAHs. The men serum IgE values were not statistically different in both group workers although in coke oven workers the tendency to higher IgE values was observed. It is rather suggested that more useful method might be the measurement of specific serum IgE.

  15. Cyclodextrin-promoted Diels Alder reactions of a polycyclic aromatic hydrocarbon under mild reaction conditions

    Science.gov (United States)

    Chaudhuri, Sauradip; Phelan, Tyler; Levine, Mindy

    2015-01-01

    Reported herein is the effect of cyclodextrins on the rates of aqueous Diels Alder reactions of 9-anthracenemethanol with a variety of N-substituted maleimides. These reactions occurred under mild reaction conditions (aqueous solvent, 40 °C), and were most efficient for the reaction of N-cyclohexylmaleimide with a methyl-β-cyclodextrin additive (94% conversion in 24 hours). These results can be explained on the basis of a model wherein the cyclodextrins bind the hydrophobic substituents on the maleimides and activate the dienophile via electronic modulation of the maleimide double bond. The results reported herein represent a new mechanism for cyclodextrin-promoted Diels Alder reactions, and have significant potential applications in the development of other cyclodextrin-promoted organic transformations. Moreover, the ability to deplanarize polycyclic aromatic hydrocarbons (PAHs) under mild conditions, as demonstrated herein, has significant applications for PAH detoxification. PMID:26692588

  16. High-resolution IR absorption spectroscopy of polycyclic aromatic hydrocarbons: the realm of anharmonicity

    CERN Document Server

    Maltseva, Elena; Candian, Alessandra; Mackie, Cameron J; Huang, Xinchuan; Lee, Timothy J; Tielens, Alexander G G M; Oomens, Jos; Buma, Wybren Jan

    2015-01-01

    We report on an experimental and theoretical investigation of the importance of anharmonicity in the 3 micron CH stretching region of Polycyclic Aromatic Hydrocarbon (PAH) molecules. We present mass-resolved, high-resolution spectra of the gas-phase cold (~4K) linear PAH molecules naphthalene, anthracene, and tetracene. The measured IR spectra show a surprisingly high number of strong vibrational bands. For naphthalene, the observed bands are well separated and limited by the rotational contour, revealing the band symmetries. Comparisons are made to the harmonic and anharmonic approaches of the widely used Gaussian software. We also present calculated spectra of these acenes using the computational program SPECTRO, providing anharmonic predictions enhanced with a Fermi-resonance treatment that utilises intensity redistribution. We demonstrate that the anharmonicity of the investigated acenes is strong, dominated by Fermi resonances between the fundamental and double combination modes, with triple combination ...

  17. Development and certification of a coal fly ash certified reference material for selected polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Cao, X; Xu, X; Cui, W; Xi, Z

    2001-08-01

    The development and certification of a coal fly ash certified reference material (CRM) for polycyclic aromatic hydrocarbons (PAH) is described; this is the first natural matrix CRM for organic environmental analysis in China. The homogeneity and stability of this material have been tested by HPLC. The concentrations of several PAH were determined by use of two independent, different methods--solvent extraction-HPLC analysis with UV detection coupled with fluorescence detection (FLD) and solvent extraction, isolation with a silica column, and GC analysis with flame ionization detection (FID). Five certified values were determined: phenanthrene 7.1 +/- 2.6 microg g(-1), anthracene 2.0 +/- 0.8 microg g(-1), fluoranthene 7.4 +/- 1.9 microg g(-1), pyrene 7 +/- 2 microg g(-1), and benzo[a]pyrene 1.3 +/- 0.3 microg g(-1). Reference values for several other PAH are also suggested. PMID:11583083

  18. Diterpanes, triterpanes, steranes, and aromatic hydrocarbons in natural bitumens and pyrolysates from different humic coals

    Science.gov (United States)

    Lu, Shan-Tan; Kaplan, Isaac R.

    1992-07-01

    Data are presented on the distribution of diterpanes, triterpanes, steranes, and aromatic hydrocarbons in the natural bitumens extracted from unheated coals identified as Rocky Mountain coal (RMC), Australian Gippsland Latrobe Eocene coal (GEC), Australian Gippsland Latrobe Cretaceous coal (GCC), and Texas Wilcox lignite (WL), as well as from pyrolysates obtained from heating of these coals. It was found that pentacyclic triterpanes are dominant in GEC, GCC, and WL, whereas diterpanes strongly predominate in the bitumen of RMC, indicating that resin is a more important constituent of RMC than of the other coals and that it releases the diterpenoids at an early stage of diagenesis. It was also found that the composition of diterpanes is different among these coals and that the distributions of sterane and triterpane in the natural bitumen of coals are very different from those of pyrolysates.

  19. Artificial neural network for modeling the extraction of aromatic hydrocarbons from lube oil cuts

    Energy Technology Data Exchange (ETDEWEB)

    Mehrkesh, A.H.; Hajimirzaee, S. [Islamic Azad University, Majlesi Branch, Isfahan (Iran, Islamic Republic of); Hatamipour, M.S.; Tavakoli, T. [Department of Chemical Engineering, University of Isfahan, Isfahan (Iran, Islamic Republic of)

    2011-03-15

    An artificial neural network (ANN) approach was used to obtain a simulation model to predict the rotating disc contactor (RDC) performance during the extraction of aromatic hydrocarbons from lube oil cuts, to produce a lubricating base oil using furfural as solvent. The field data used for training the ANN model was obtained from a lubricating oil production company. The input parameters of the ANN model were the volumetric flow rates of feed and solvent, the temperatures of feed and solvent, and the disc rotation rate. The output parameters were the volumetric flow rate of the raffinate phase and the extraction yield. In this study, a feed-forward multi-layer perceptron neural network was successfully used to demonstrate the complex relationship between the mentioned input and output parameters. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Toxicity assessment of polycyclic aromatic hydrocarbons in sediments from European high mountain lakes.

    Science.gov (United States)

    Quiroz, Roberto; Grimalt, Joan O; Fernández, Pilar

    2010-05-01

    Sediment quality guidelines and toxic equivalent factors have been used for assessment of the toxicity of sedimentary long-range atmospherically transported polycyclic aromatic hydrocarbons (PAHs) to the organisms living in high mountain European lakes. This method has provided indices that are consistent with experimental studies evaluating in situ sedimentary estrogenic activity or physiological response to AhR binding in fish from the same lakes. All examined lakes in north, central, west, northeast and southeast European mountains have shown sedimentary PAH concentrations that are above thresholds of no effect but only those situated in the southeast lakes district exhibited concentrations above the indices of probable effects. These mountains, Tatras, are also those having PAH concentrations of highest activity for AhR binding. Chrysene+triphenylene, dibenz[a]anthracene, benzo[k]fluoranthene and indeno[1,2,3-cd]pyrene are the main compounds responsible for the observed toxic effects.

  1. A molecular dynamics study on slow ion interactions with the polycyclic aromatic hydrocarbon molecule anthracene

    International Nuclear Information System (INIS)

    Atomic collisions with polycyclic aromatic hydrocarbon (PAH) molecules are astrophysically particularly relevant for collision energies of less than 1 keV. In this regime, the interaction dynamics are dominated by elastic interactions. We have employed a molecular dynamics simulation based on analytical interaction potentials to model the interaction of low energy hydrogen and helium projectiles with isolated anthracene (C14H10) molecules. This approach allows for a very detailed investigation of the elastic interaction dynamics on an event by event basis. From the simulation data the threshold projectile kinetic energies above which direct C atom knock out sets in were determined. Anthracene differential energy transfer cross sections and total (dissociation) cross sections were computed for a wide range of projectile kinetic energies. The obtained results are interpreted in the context of PAH destruction in astrophysical environments.

  2. Sedimentary record of polycyclic aromatic hydrocarbons in Lake Erhai,Southwest China

    Institute of Scientific and Technical Information of China (English)

    Jianyang Guo; Zhang Liang; Haiqing Liao; Zhi Tang; Xiaoli Zhao; Fengchang Wu

    2011-01-01

    The temporal distribution of polycyclic aromatic hydrocarbons (PAHs) was investigated in a sediment core from Lake Erhal in Southwest China using gas-chromatography/mass spectrometry (GC/MS) method.The total organic carbon (TOC) normalized total PAHs concentrations (sum of US Environmental Protection Agency proposed 16 priority PAHs) ranged from 31.9 to 269 μg/g dry weight (dw),and were characterized by a slowly increasing stage in the deeper sediments and a sharp increasing stage in the upper sediments.The PAHs in the sediments were dominated by low molecular weight (LMW) PAHs,suggesting that the primary source of PAHs was low- and moderate temperature combustion processes.However,both the significant increase in high molecular weight (HMW) PAHs in the upper sediments and the vertical profile of diagnostic ratios pointed out a change in the sources of PAHs from low-temperature combustion to high-temperature combustion.The ecotoxicological assessment based on consensus-based sediment quality guidelines implied that potential adverse biological impacts were possible for benzo(ghi)perylenelene and most LMW PAHs.In addition,the total BaP equivalent quotient of seven carcinogenic polycyclic aromatic hydrocarbons (BaA,CHr,BbF,BkF,BaP,DBA and INP) was 106.1 ng/g,according to the toxic equivalency factors.Although there was no great biological impact associated with the HMW PAlls,great attention should be paid to these PAH components based on their rapid increase in the upper sediments.

  3. [Improving Agricultural Safety of Soils Contaminated with Polycyclic Aromatic Hydrocarbons by In Situ Bioremediation].

    Science.gov (United States)

    Jiao, Hai-huan; Pan, Jian-gang; Xu, Shena-jun; Bai, Zhi-hui; Wang, Dong; Huang, Zhan-bin

    2015-08-01

    In order to reduce the risk of enrichment of polycyclic aromatic hydrocarbons (PAHs) in crops, reduce the potential hazards of food-sourced PAHs to human and increase the agricultural safety of PAHs contaminated soils, the bio-augmented removal of polycyclic aromatic hydrocarbons (PAHs) was investigated through in situ remediation by introducing Rhodobacter sphaeroides (RS) into the agricultural soil contaminated by PAHs. The 50-times diluted RS was sprayed on leaf surface (in area B) or irrigated to roots (in area D). The treatment of spraying water of the equal amount was taken as the control (A) and the wheat field without any treatment as the blank (CK). Treatments were conducted since wheat seeding. Soil and wheat samples were collected in the mature period to analyze the changes of community structure of the soil microorganisms and the concentration of PAHs in soils and investigate the strengthening and restoration effects of RS on PAHs contaminated soils. Compared to the CK Area, the areas B and D revealed that the variation ratio of phospholipid fatty acids (PLFAs) that were the biomarker of soil microorganisms was 29.6%, and the ratio of total PAHs removed was increased 1.59 times and 1.68 times, respectively. The dry weight of wheat grain of 50 spikes was increased by 8.95% and 12.5%, respectively, and the enrichment factor of total PAHs was decreased by 58.9% and 62.2% respectively in the wheat grains. All the results suggested that RS reduced enrichment of PAHs in wheat grains and increased wheat yield, which had great exploitation and utilization potentiality in repairing and improving the agricultural safety of the soils contaminated with PHAs.

  4. Enhanced dissipation of polycyclic aromatic hydrocarbons in the presence of fresh plant residues and their extracts

    International Nuclear Information System (INIS)

    The feasibility of using fresh plant residues and their extracts to stimulate the bio-dissipation of polycyclic aromatic hydrocarbons (PAHs) were highlighted. Wood chip, bamboo leave, orange peel and their water-extractable organic matter (WEOM) were chosen as amendment materials. Effect of WEOM on bio-dissipation (bioaccumulation and biodegradation) of phenanthrene and pyrene from water by two bacteria were investigated. Orange peel extract demonstrated the highest efficiency for stimulating PAHs removal by bacterium B1 (Pseudomonas putida), while bamboo leave extract was the best one to enhance PAHs bio-dissipation by bacterium B2 (unidentified bacterium isolated from PAHs-contaminated soil). Amended the actual contaminated soil with 1% plant residues, PAHs dissipation were increased by 15–20%, 20–39%, 14–24%, 12–23% and 17–26%, respectively, for 2-, 3-, 4-, 5- and 6-ring PAHs via stimulating indigenous microbial degradation activity. Bamboo leave exhibited the most effective one to stimulate dissipation of PAHs in contaminated soil. - Graphical abstract: Enhanced bio-dissipation of 15 PAHs in soil amended with fresh plant residues of wood chip (WC), orange peel (OP), and bamboo leave (BL). The individual symbol of AC, EC and BC is the abiotic sterile control, evaporation control and blank control. Highlights: ► The addition of fresh plant extracts significantly enhance PAHs bio-dissipation from water. ► Bioaccumulation and biodegradation contribute to the bio-dissipation of PAHs in solution. ► The added fresh plant residues promotes 15 PAHs dissipation in PAHs-contaminated soil. ► Stimulating indigenous microbial degradation activity contributes to PAHs dissipation. ► Bamboo leave exhibits the most effective one to stimulate dissipation of PAHs in soil. - It is feasible to amend fresh plant residues and their extracts to stimulate the bio-dissipation of polycyclic aromatic hydrocarbons in the contaminated environment.

  5. Biodiesel presence in the source zone hinders aromatic hydrocarbons attenuation in a B20-contaminated groundwater

    Science.gov (United States)

    Ramos, Débora Toledo; Lazzarin, Helen Simone Chiaranda; Alvarez, Pedro J. J.; Vogel, Timothy M.; Fernandes, Marilda; do Rosário, Mário; Corseuil, Henry Xavier

    2016-10-01

    The behavior of biodiesel blend spills have received limited attention in spite of the increasing and widespread introduction of biodiesel to the transportation fuel matrix. In this work, a controlled field release of biodiesel B20 (100 L of 20:80 v/v soybean biodiesel and diesel) was monitored over 6.2 years to assess the behavior and natural attenuation of constituents of major concern (e.g., BTEX (benzene, toluene, ethyl-benzene and xylenes) and PAHs (polycyclic aromatic hydrocarbons)) in a sandy aquifer material. Biodiesel was preferentially biodegraded compared to diesel aromatic compounds with a concomitant increase in acetate, methane (near saturation limit (≈ 22 mg L- 1)) and dissolved BTEX and PAH concentrations in the source zone during the first 1.5 to 2.0 years after the release. Benzene and benzo(a)pyrene concentrations remained above regulatory limits in the source zone until the end of the experiment (6.2 years after the release). Compared to a previous adjacent 100-L release of ethanol-amended gasoline, biodiesel/diesel blend release resulted in a shorter BTEX plume, but with higher residual dissolved hydrocarbon concentrations near the source zone. This was attributed to greater persistence of viscous (and less mobile) biodiesel than the highly-soluble and mobile ethanol in the source zone. This persistence of biodiesel/diesel NAPL at the source zone slowed BTEX and PAH biodegradation (by the establishment of an anaerobic zone) but reduced the plume length by reducing mobility. This is the first field study to assess biodiesel/diesel blend (B20) behavior in groundwater and its effects on the biodegradation and plume length of priority groundwater pollutants.

  6. Removal of polycyclic aromatic hydrocarbons from organic solvents by ashes wastes

    International Nuclear Information System (INIS)

    Polycyclic aromatic hydrocarbons (PAHs) can be formed during the refinery processes of crude petroleum. Their removal is of great importance. The same happens with other organic solvents used for the extraction of PAHs (hexane, acetonitrile...), which can be polluted with PAHs. Kinetic and equilibrium batch sorption tests were used to investigate the effect of wood ashes wastes as compared to activated carbon on the sorption of three representative PAHs from n-hexane and acetonitrile. Mussel shell ashes were discarded for batch sorption experiments because they were the only ashes containing PAHs. The equilibrium time was reached at 16 h. Physical sorption caused by the aromatic nature of the compounds was the main mechanism that governed the PAHs removal process. Our investigation revealed that wood ashes obtained at lower temperature (300 deg. C) did not show any PAHs sorption, while ashes obtained at higher temperature (>500 deg. C) have adsorbent sites readily available for the PAH molecules. An increase in the molecular weight of PAHs has a strong effect on sorption wood ashes wastes. As low the wood ashes particle size as high the sorption of PAHs, as a result of differences in adsorbent sites. The performance of wood ash wastes vs. activated carbon to remove 10 PAHs from organic solvents is competitive in price, and a good way for waste disposal.

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

    Science.gov (United States)

    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.

  8. Polycyclic Aromatic Hydrocarbons and Breast Cancer: A Review of the Literature.

    Science.gov (United States)

    Korsh, Jessica; Shen, Allison; Aliano, Kristen; Davenport, Thomas

    2015-10-01

    Polycyclic aromatic hydrocarbons (PAHs) exist and persist in the atmosphere due to the incomplete combustion of fossil fuels, and are established human carcinogens. The influence of PAHs on the development of breast cancer, the most commonly diagnosed cancer in women worldwide, remains unclear. As established risk factors only account for approximately 41% of the breast cancer cases in the USA, researchers have sought to uncover environmental factors involved in breast cancer development. The breasts are particularly susceptible to aromatic carcinogenesis, and the implementation of biomarkers has provided promising insights regarding PAH-DNA adducts in breast cancer. The use of biomarkers measuring PAH-DNA adducts assesses exposure to eliminate the bias inherent in self-reporting measures in case-control studies investigating the link between PAHs and cancer. Adduct levels reflect exposure dose as well as how the body responds to this exposure, which is partially attributable to genetic variability. Evidence suggests that exposure to PAHs has a causational effect on breast cancer in humans, yet this interaction is not clearly understood. In vitro and animal-based studies have consistently revealed that exposure to PAHs deleteriously affects breast tissue, but there is no definitive link between these compounds and breast cancer. PMID:26688678

  9. Tumour-promoting activity of polycyclic aromatic hydrocarbons and their oxygenated or nitrated derivatives.

    Science.gov (United States)

    Misaki, Kentaro; Takamura-Enya, Takeji; Ogawa, Hideoki; Takamori, Kenji; Yanagida, Mitsuaki

    2016-03-01

    Various types of polycyclic aromatic compounds (PACs) in diesel exhaust particles are thought to contribute to carcinogenesis in mammals. Although the carcinogenicity, mutagenicity and tumour-initiating activity of these compounds have been evaluated, their tumour-promoting activity is unclear. In the present study, to determine the tumour-inducing activity of PACs, including previously known mutagenic compounds in atmospheric environments, a transformation assay for promoting activity mediated by the release of contact inhibition was conducted for six polycyclic aromatic hydrocarbons (PAHs), seven oxygenated PAHs (oxy-PAHs) and seven nitrated PAHs (nitro-PAHs) using mouse embryonic fibroblast cells transfected with the v-Ha-ras gene (Bhas 42 cells). Of these, two PAHs [benzo[k]fluoranthene (B[k]FA) and benzo[b]fluoranthene (B[b]FA)], one oxy-PAH [6H-benzo[cd]pyren-6-one (BPO)] and two nitro-PAHs (3-nitro-7H-benz[de]anthracen-7-one and 6-nitrochrysene) were found to exhibit particularly powerful tumour-promoting activity (≥10 foci following exposure to BPO). Further, an HO-1 antioxidant response activation was observed following exposure to B[k]FA, B[b]FA and BPO, suggesting that the induction of tumour-promoting activity in these compounds is correlated with the dysfunction of signal transduction via AhR-mediated responses and/or oxidative stress responses.

  10. High-Resolution IR Absorption Spectroscopy of Polycyclic Aromatic Hydrocarbons: The Realm of Anharmonicity

    Science.gov (United States)

    Maltseva, Elena; Petrignani, Annemieke; Candian, Alessandra; Mackie, Cameron J.; Huang, Xinchuan; Lee, Timothy J.; Tielens, Alexander G. G. M.; Oomens, Jos; Buma, Wybren Jan

    2016-01-01

    We report on an experimental and theoretical investigation of the importance of anharmonicity in the 3 micrometers CH stretching region of Polycyclic Aromatic Hydrocarbon (PAH) molecules. We present mass-resolved, high-resolution spectra of the gas-phase cold ((is) approximately 4K) linear PAH molecules naphthalene, anthracene, and tetracene. The measured IR spectra show a surprisingly high number of strong vibrational bands. For naphthalene, the observed bands are well separated and limited by the rotational contour, revealing the band symmetries. Comparisons are made to the harmonic and anharmonic approaches of the widely used Gaussian software. We also present calculated spectra of these acenes using the computational program SPECTRO, providing anharmonic predictions enhanced with a Fermi-resonance treatment that utilizes intensity redistribution. We demonstrate that the anharmonicity of the investigated acenes is strong, dominated by Fermi resonances between the fundamental and double combination modes, with triple combination bands as possible candidates to resolve remaining discrepancies. The anharmonic spectra as calculated with SPECTRO lead to predictions of the main modes that fall within 0.5% of the experimental frequencies. The implications for the Aromatic Infrared Bands, specifically the 3-m band are discussed.

  11. Polycyclic aromatic hydrocarbons in sediments and mussels of the western Mediterranean Sea

    Energy Technology Data Exchange (ETDEWEB)

    Baumard, P.; Budzinski, H.; Garrigues, P. [Univ. Bordeaux I, Talence (France)

    1998-05-01

    The distribution of polycyclic aromatic hydrocarbons (PAHs) has been investigated in superficial sediments and mussels (Mytilus galloprovincialis) of the western Mediterranean sea. The analyses were performed by gas chromatography coupled to mass spectrometry (GC-MS). The PAH concentrations ranged from 1 to 20,500 ng/g in the sediments. Different molecular indices allowed differentiation between the different pollutant sources. On the French coast, PAHs originated mainly from incomplete combustion of organic matter (pyrolytic origin), whereas for some sites in Corsica and Sardinia an overimposition of petrogenic PAHs occurred. The mussel PAH concentrations ranged from 25 to 390 ng/g. The total and individual PAH bioaccumulation factors were calculated. The correlation between sediment and mussel PAH content was discussed in terms of bioavailability. It was possible to distinguish different absorption routes for the xenobiotics according to their physicochemical properties. Because the mussel distribution of phenanthrene and anthracene seems to be governed by their water solubility, these compounds were probably mainly absorbed as the water-dissolved form, whereas the heavier molecular weight PAHs (more than four aromatic rings), whose sediment and mussel concentrations are correlated with higher correlation coefficients than for phenanthrene and anthracene, were probably mainly absorbed as adsorbed on particles. Furthermore, a possible preferential biotransformation of benzo[a]pyrene over benzo[e]pyrene is discussed.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-02-15

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

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

    Science.gov (United States)

    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. PMID:27037474

  14. Phototoxicity of individual polycyclic aromatic hydrocarbons and petroleum to marine invertebrate larvae and juveniles

    International Nuclear Information System (INIS)

    Phototoxicity resulting from photoactivated polycyclic aromatic hydrocarbons (PAHs) has been reported in the literature for a variety of freshwater organisms. The magnitude of increase in PAH toxicity often exceeds a factor of 100. In the marine environment phototoxicity to marine organisms has not been reported for individual or complex mixtures of PAHs. In this study, larvae and juveniles of the bivalve, Mulinia lateralis, and juveniles of the mysid shrimp, Mysidopsis bahia, were exposed to individual known phototoxic PAHs (anthracene, fluoranthene, pyrene), as well as the water-accommodated fractions of several petroleum products (Fuel Oil number-sign 2, Arabian Light Crude, Prudhoe Bay Crude, Fuel Oil number-sign 6) containing PAHs. Phototoxicity of individual PAHs was 12 to >50,000 times that of conventional toxicity. Three of the petroleum products demonstrated phototoxicity while the lightest product, Fuel Oil number-sign 2, was not phototoxic at the concentrations tested. The phototoxicity of petroleum products appears to be dependent on the composition and concentrations of phototoxic PAHs present: lighter oils have fewer multiple aromatic ring, phototoxic compounds while heavier oils have higher levels of these types of molecules. This study shows that phototoxicity can occur in marine waters to marine species. Further, the occurrence of oil in marine waters presents the additional risk of phototoxicity not routinely assessed for during oil spills

  15. Release behavior and formation mechanism of polycyclic aromatic hydrocarbons during coal pyrolysis.

    Science.gov (United States)

    Gao, Meiqi; Wang, Yulong; Dong, Jie; Li, Fan; Xie, Kechang

    2016-09-01

    Polycyclic aromatic hydrocarbons (PAHs) are major environmental pollutants. They have attracted considerable attention due to their severe potential carcinogenic, mutagenic and genotoxic effects on human health. In this study, five different rank coals from China were pyrolyzed using pyro-probe CDS 5250 and the release behavior of 16 PAHs under different pyrolysis conditions were studied by Gas Chromatography-Mass Spectrometer (GC-MS). The structural characteristics of the five coals were determined by Cross-Polarization/Magic Angle Spinning Carbon-13 Nuclear Magnetic Resonance (CP/MAS (13)C NMR) spectroscopy, and then the factors influencing the formation of PAHs during coal pyrolysis were discussed together with the coal structural data. It was shown that the amount of PAHs generated during coal pyrolysis was largely related to coal rank and followed the order of medium metamorphic coal > low metamorphic coal > high metamorphic coal. The amount of total PAHs varied as the temperature was increased from 400 °C to 1200 °C, which showed a trend of first increasing and then decreasing, with the maximum value at 800 °C. Moreover, the species of PAHs released varied with pyrolysis temperatures. When the temperature was lower than 800 °C, the small ring PAHs were the most abundant, while the proportion of heavy rings increased at higher temperature. The results indicate that the formation of PAHs during coal pyrolysis depends on the structure of the coal. The species and amounts of PAHs generated during coal pyrolysis are closely related to the contents of protonated aromatic carbons and bridging ring junction aromatic carbons present in the coal structure. PMID:27239965

  16. Release behavior and formation mechanism of polycyclic aromatic hydrocarbons during coal pyrolysis.

    Science.gov (United States)

    Gao, Meiqi; Wang, Yulong; Dong, Jie; Li, Fan; Xie, Kechang

    2016-09-01

    Polycyclic aromatic hydrocarbons (PAHs) are major environmental pollutants. They have attracted considerable attention due to their severe potential carcinogenic, mutagenic and genotoxic effects on human health. In this study, five different rank coals from China were pyrolyzed using pyro-probe CDS 5250 and the release behavior of 16 PAHs under different pyrolysis conditions were studied by Gas Chromatography-Mass Spectrometer (GC-MS). The structural characteristics of the five coals were determined by Cross-Polarization/Magic Angle Spinning Carbon-13 Nuclear Magnetic Resonance (CP/MAS (13)C NMR) spectroscopy, and then the factors influencing the formation of PAHs during coal pyrolysis were discussed together with the coal structural data. It was shown that the amount of PAHs generated during coal pyrolysis was largely related to coal rank and followed the order of medium metamorphic coal > low metamorphic coal > high metamorphic coal. The amount of total PAHs varied as the temperature was increased from 400 °C to 1200 °C, which showed a trend of first increasing and then decreasing, with the maximum value at 800 °C. Moreover, the species of PAHs released varied with pyrolysis temperatures. When the temperature was lower than 800 °C, the small ring PAHs were the most abundant, while the proportion of heavy rings increased at higher temperature. The results indicate that the formation of PAHs during coal pyrolysis depends on the structure of the coal. The species and amounts of PAHs generated during coal pyrolysis are closely related to the contents of protonated aromatic carbons and bridging ring junction aromatic carbons present in the coal structure.

  17. Determining produced water originating polycyclic aromatic hydrocarbons in North Sea waters: comparison of sampling techniques

    International Nuclear Information System (INIS)

    A field study was carried out in the Norwegian sector of the North Sea during May and June 1997. The purpose was to measure the concentration of produced water originating polycyclic aromatic hydrocarbons (PAH) in seawater and to compare different sampling techniques for use in future monitoring programs. Three methods were used for direct water sampling: (1) in situ large volume sampling of particulate and dissolved hydrocarbons onto filters and XAD resins, (2) solid phase extraction (SPE) using polystyrene-divinylbenzene disks, (3) whole bulk water sampling. In addition, sampling by semi-permeable membrane devices (SPMDs) and blue mussels (Mytilus edulis) was used to obtain a 4 weeks average of the concentration of the target compounds in seawater. The samples were processed and analysed by GC-MS for determination of PAH concentrations. The measured concentrations were generally found to be low, and in many cases below the limits of detection. The comparison of sampling techniques showed that blue mussels and SPMDs are suitable for measuring PAH in both near-and far-field seawater. In situ large volume water sampling was also suitable for a wide range of PAH concentrations, but this technique was limited by high break-through of the low-molecular weight compounds, such as naphthalenes. The small sampling volumes limited the SPE and whole water sampling techniques, resulting in potential detection limit problems These grab-sampling techniques may, however, be suitable for monitoring in the near-field areas around the platforms. (Author)

  18. LABORATORY INVESTIGATIONS OF POLYCYCLIC AROMATIC HYDROCARBON FORMATION AND DESTRUCTION IN THE CIRCUMSTELLAR OUTFLOWS OF CARBON STARS

    Energy Technology Data Exchange (ETDEWEB)

    Contreras, Cesar S.; Salama, Farid, E-mail: cesar.contreras@nasa.gov, E-mail: Farid.Salama@nasa.gov [Space Science and Astrobiology Division, NASA-Ames Research Center, Moffett Field, CA 94035 (United States)

    2013-09-15

    The formation and destruction mechanisms of interstellar dust analogs formed from a variety of polycyclic aromatic hydrocarbon (PAH) and hydrocarbon molecular precursors are studied in the laboratory. We used the newly developed facility COSmIC, which simulates interstellar and circumstellar environments, to investigate both PAHs and species that include the cosmically abundant atoms O, N, and S. The species generated in a discharge plasma are detected, monitored, and characterized in situ using highly sensitive techniques that provide both spectral and ion mass information. We report here the first series of measurements obtained in these experiments which focus on the characterization of the most efficient molecular precursors in the chemical pathways that eventually lead to the formation of carbonaceous grains in the stellar envelopes of carbon stars. We compare and discuss the relative efficiencies of the various molecular precursors that lead to the formation of the building blocks of carbon grains. We discuss the most probable molecular precursors in terms of size and structure and the implications for the expected growth and destruction processes of interstellar carbonaceous dust.

  19. Does chemically dispersing crude oil increase the exposure of fish to polynuclear aromatic hydrocarbons (PAH)?

    Energy Technology Data Exchange (ETDEWEB)

    Ramachandran, S.D.; Khan, C.W.; Hodson, P.V. [Queen' s Univ., Kingston, ON (Canada). Dept. of Biology; Lee, K. [Department of Fisheries and Oceans, Dartmouth, NS (Canada). Bedford Inst. of Oceanography

    2002-07-01

    Dispersants or surfactants are often used to clean up oil spills on water to minimize the impact of oil pollution. Their use as an oil spill countermeasure, however, is controversial because the risk of ecological effects depends on whether the dispersant increases or decreases the exposure of aquatic species to the toxic components of oil. This study involved the measurement of CYP1A induction and bile metabolites of polycyclic aromatic hydrocarbons (PAH) in trout exposed to Corexit 9500 dispersant, water accommodated fractions, and chemically enhanced water accommodated fractions of 3 crude oils. The objective was to see if fish are exposed to more PAH in dispersed oil compared to equivalent amounts of water accommodated fraction. Preliminary results indicated 10 times higher induction in fish exposed to chemically enhanced water accommodated fraction compared to water accommodated fractions. The dispersed oil in water had higher concentrations of alkylated PAH compared to the water accommodated fraction. As hydrocarbon concentrations increased, the trend for medaka embryos was first to hatch earlier, then have mild edema, followed by severe edema and finally mortality.

  20. Assessing the Ecological Risk of Polycyclic Aromatic Hydrocarbons in Sediments at Langkawi Island, Malaysia

    Directory of Open Access Journals (Sweden)

    Essam Nasher

    2013-01-01

    Full Text Available Tourism-related activities such as the heavy use of boats for transportation are a significant source of petroleum hydrocarbons that may harm the ecosystem of Langkawi Island. The contamination and toxicity levels of polycyclic aromatic hydrocarbon (PAH in the sediments of Langkawi were evaluated using sediment quality guidelines (SQGs and toxic equivalent factors. Ten samples were collected from jetties and fish farms around the island in December 2010. A gas chromatography/flame ionization detector (GC/FID was used to analyse the 18 PAHs. The concentration of total PAHs was found to range from 869 ± 00 to 1637 ± 20 ng g−1 with a mean concentration of 1167.00 ± 24 ng g−1, lower than the SQG effects range-low (3442 ng g−1. The results indicated that PAHs may not cause acute biological damage. Diagnostic ratios and principal component analysis suggested that the PAHs were likely to originate from pyrogenic and petrogenic sources. The toxic equivalent concentrations of the PAHs ranged from 76.3 to 177 ng TEQ/g d.w., which is lower compared to similar studies. The results of mean effects range-median quotient of the PAHs were lower than 0.1, which indicate an 11% probability of toxicity effect. Hence, the sampling sites were determined to be the low-priority sites.

  1. Assessing the ecological risk of polycyclic aromatic hydrocarbons in sediments at Langkawi Island, Malaysia.

    Science.gov (United States)

    Nasher, Essam; Heng, Lee Yook; Zakaria, Zuriati; Surif, Salmijah

    2013-01-01

    Tourism-related activities such as the heavy use of boats for transportation are a significant source of petroleum hydrocarbons that may harm the ecosystem of Langkawi Island. The contamination and toxicity levels of polycyclic aromatic hydrocarbon (PAH) in the sediments of Langkawi were evaluated using sediment quality guidelines (SQGs) and toxic equivalent factors. Ten samples were collected from jetties and fish farms around the island in December 2010. A gas chromatography/flame ionization detector (GC/FID) was used to analyse the 18 PAHs. The concentration of total PAHs was found to range from 869 ± 00 to 1637 ± 20 ng g⁻¹ with a mean concentration of 1167.00 ± 24 ng g⁻¹, lower than the SQG effects range-low (3442 ng g⁻¹). The results indicated that PAHs may not cause acute biological damage. Diagnostic ratios and principal component analysis suggested that the PAHs were likely to originate from pyrogenic and petrogenic sources. The toxic equivalent concentrations of the PAHs ranged from 76.3 to 177 ng TEQ/g d.w., which is lower compared to similar studies. The results of mean effects range-median quotient of the PAHs were lower than 0.1, which indicate an 11% probability of toxicity effect. Hence, the sampling sites were determined to be the low-priority sites. PMID:24163633

  2. LABORATORY INVESTIGATIONS OF POLYCYCLIC AROMATIC HYDROCARBON FORMATION AND DESTRUCTION IN THE CIRCUMSTELLAR OUTFLOWS OF CARBON STARS

    International Nuclear Information System (INIS)

    The formation and destruction mechanisms of interstellar dust analogs formed from a variety of polycyclic aromatic hydrocarbon (PAH) and hydrocarbon molecular precursors are studied in the laboratory. We used the newly developed facility COSmIC, which simulates interstellar and circumstellar environments, to investigate both PAHs and species that include the cosmically abundant atoms O, N, and S. The species generated in a discharge plasma are detected, monitored, and characterized in situ using highly sensitive techniques that provide both spectral and ion mass information. We report here the first series of measurements obtained in these experiments which focus on the characterization of the most efficient molecular precursors in the chemical pathways that eventually lead to the formation of carbonaceous grains in the stellar envelopes of carbon stars. We compare and discuss the relative efficiencies of the various molecular precursors that lead to the formation of the building blocks of carbon grains. We discuss the most probable molecular precursors in terms of size and structure and the implications for the expected growth and destruction processes of interstellar carbonaceous dust

  3. Human health risk due to consumption of vegetables contaminated with carcinogenic polycyclic aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Sardar [Chinese Academy of Sciences, Xiamen (China). Inst. of Urban Environment; Peshawar Univ. (Pakistan). Dept. of Environmental Science; Cao, Qing [Chinese Academy of Sciences, Beijing (China). Research Center for Eco-Environemntal Sciences

    2012-02-15

    Polycyclic aromatic hydrocarbons (PAH) are persistent, toxic, and carcinogenic contaminants present in soil ecosystem globally. These pollutants are gradually accumulating in wastewater-irrigated soils and lead to the contamination of vegetables. Food chain contamination with PAH is considered as one of the major pathways for human exposure. This study was aimed to investigate the concentrations of PAH in soils and vegetables collected from wastewater-irrigated fields from metropolitan areas of Beijing, China. Origin of PAH, daily intake, and health risks of PAH through consumption of contaminated vegetables were studied. Soil samples were collected from the upper horizon (0-20 cm) of both wastewater-irrigated and reference sites and sieved (<2 mm mesh) and then followed by freeze-drying at -50 C and 123 {+-} 2 Pa. Standing vegetables were also collected from the same sites used for soil sampling and divided into roots and shoots, thoroughly washed with deionized water, and freeze-dried. PAH were extracted using the Soxhlet method with 200 mL DCM for 24 h, and the extracts were cleaned with silica adsorption chromatography prepared with silica gel, alumina, and capped with anhydrous sodium. The final concentrated extracts (soil and vegetable) were analyzed using gas chromatography-mass spectrometry (Agilent 6890). Bioaccumulation factors, daily intake of PAH, and carcinogenicity of PAH were calculated by different statistical equations. Results indicate that the soils and grown vegetables were contaminated with all possible carcinogenic PAH (declared by USEPA 2002) except indeno[1,2,3-c,d]pyrene. The highest concentration (242.9 {mu}g kg{sup -1}) was found for benzo(k)fluoranthene (BkF), while lowest (79.12 {mu}g kg{sup -1}) for benzo[a]pyrene (BaP). The emission sources of PAH were both pyrogenic and petrogenic in nature. However, the total concentrations of PAH were lower than the permissible limits set by different countries like Canada, Denmark and Germany

  4. Polycyclic aromatic hydrocarbons (PAHs) in atmospheric PM2.5 around 2013 Asian Youth Games period in Nanjing

    Science.gov (United States)

    Li, Xuxu; Kong, Shaofei; Yin, Yan; Li, Li; Yuan, Liang; Li, Qi; Xiao, Hui; Chen, Kui

    2016-06-01

    Eighteen polycyclic aromatic hydrocarbons (PAHs) in PM2.5 collected near the Nanjing Olympic Sports Center across the Asian Youth Games (AYG) period (from August 2 to August 28, 2013) were analyzed using GC-MS. Their levels, sources and health risks to human were discussed. Results showed that the total concentrations of PAHs in PM2.5 were 9.43, 7.21 and 8.83 ng m- 3 for pre- (August 3-15), during- (August 16-24) and post- (August 25-28) AYG periods, respectively. They were dominated by 5-ring and 6-ring PAHs. Total PAHs concentrations in PM2.5 during AYG period decreased by 24%, when compared with those for pre-AYG period. For combustion-derived PAHs and carcinogenic PAHs, they decreased by 26% and 21%, respectively. It implied that the pollution control measures implemented during the AYG can effectively reduce the emission of PAHs from various sources. The poor correlations between PAHs and meteorological parameters also favored that the variations of PAHs were raised by the changes of emission sources. Diagnostic ratios and principal component analysis revealed that vehicle emission and coal combustion were the predominant contributors, with minimal effects from biomass burning and petroleum. The health risks for human exposed to PAHs in PM2.5 were quantitatively assessed by BaP equivalent concentration (BaPeq) and the incremental lifetime cancer risk (ILCR). The estimated ILCR value of PAHs during the AYG periods decreased by 23% and 27% for children and adults when compared with those for the pre-AYG, respectively. It indicated that the pollution control measures reduced the risks of PAHs to sportsmen or human gathered around the Olympic Sport Center.

  5. Source Contribution Analysis of Surface Particulate Polycyclic Aromatic Hydrocarbon Concentrations in Northeastern Asia by Source-receptor Relationships

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-11-01

    We analyzed the sourceereceptor relationships for particulate polycyclic aromatic hydrocarbon (PAH) concentrations in northeastern Asia using an aerosol chemical transport model. The model successfully simulated the observed concentrations. In Beijing (China) benzo[a]pyren (BaP) concentrations are due to emissions from its own domain. In Noto, Oki and Tsushima (Japan), transboundary transport from northern China (>40°N, 40-60%) and central China (30-40°N, 10-40%) largely influences BaP concentrations from winter to spring, whereas the relative contribution from central China is dominant (90%) in Hedo. In the summer, the contribution from Japanese domestic sources increases (40-80%) at the 4 sites. Contributions from Japan and Russia are additional source of BaP over the northwestern Pacific Ocean in summer. The contribution rates for the concentrations from each domain are different among PAH species depending on their particulate phase oxidation rates. Reaction with O3 on particulate surfaces may be an important component of the PAH oxidation processes.

  6. The source apportionment of polycyclic aromatic hydrocarbons (PAHs) in the topsoil in Xiaodian sewage irrigation area, North of China.

    Science.gov (United States)

    Li, Jia-Le; Wang, Yan-Xin; Zhang, Cai-Xiang; Dong, Yi-Hui; Du, Bin; Liao, Xiao-Ping

    2014-12-01

    31 topsoil samples were collected by grid method in Xiaodian sewage irrigation area, Taiyuan City, North of China. The concentrations of 16 kinds of polycyclic aromatic hydrocarbons (PAHs) were determined by gas chromatograph coupled with mass spectrum. Generally speaking, the distribution order of PAHs in the area is: those with five and six rings > those with four rings > those with two and three rings. Source apportionment shows a significant zonation of the source of PAHs: the civil coal pollution occurred in the north part, the local and far factory pollution happened in the middle area and the mixed pollution sources from coal and wood combustion, automotive emission, presented in the south area. The distribution of PAHs has a definite relationship with the sewage water flow and soil adsorption. The related coefficient between PAHs and physicochemical property showed there was a negative correlation between pH, silt, clay and PAHs while there was a positive correlation between total organic carbon, sand and PAHs. PMID:25139034

  7. Assessment of polycyclic aromatic hydrocarbons (PAHs) contamination in surface soil of coal stockpile sites in South Kalimantan, Indonesia.

    Science.gov (United States)

    Mizwar, Andy; Priatmadi, Bambang Joko; Abdi, Chairul; Trihadiningrum, Yulinah

    2016-03-01

    Concentrations, spatial distribution, and sources of 16 polycyclic aromatic hydrocarbons (PAHs), listed as priority pollutants by the United States Environmental Protection Agency (USEPA), were investigated in surface soils of three different coal stockpile, agricultural, and residential sites in South Kalimantan Province, Indonesia. Total PAHs concentration ranged from 4.69 to 22.67 mg kg(-1)-dw. PAHs concentrations in soil of coal stockpile sites were higher than those in agricultural and residential soil. A complex of petrogenic origin and pyrolytic sources was found within the study area, as suggested by the isomeric ratios of PAHs. The results of principal component analysis and multiple linear regressions (PCA/MLR) showed that three sources contributed to the PAHs in the study area, including biomass and coal combustion (48.46%), raw coal (35.49%), and vehicular emission (16.05%). The high value of total benzo[a]pyrene equivalent concentration (B[a]Peq) suggests that local residents are exposed to a high carcinogenic potential.

  8. Size distributions of polycyclic aromatic hydrocarbons in urban atmosphere: sorption mechanism and source contributions to respiratory deposition

    Science.gov (United States)

    Lv, Yan; Li, Xiang; Xu, Ting Ting; Cheng, Tian Tao; Yang, Xin; Chen, Jian Min; Iinuma, Yoshiteru; Herrmann, Hartmut

    2016-03-01

    In order to better understand the particle size distribution of polycyclic aromatic hydrocarbons (PAHs) and their source contribution to human respiratory system, size-resolved PAHs have been studied in ambient aerosols at a megacity Shanghai site during a 1-year period (2012-2013). The results showed the PAHs had a bimodal distribution with one mode peak in the fine-particle size range (0.4-2.1 µm) and another mode peak in the coarse-particle size range (3.3-9.0 µm). Along with the increase in ring number of PAHs, the intensity of the fine-mode peak increased, while the coarse-mode peak decreased. Plotting of log(PAH / PM) against log(Dp) showed that all slope values were above -1, suggesting that multiple mechanisms (adsorption and absorption) controlled the particle size distribution of PAHs. The total deposition flux of PAHs in the respiratory tract was calculated as being 8.8 ± 2.0 ng h-1. The highest lifetime cancer risk (LCR) was estimated at 1.5 × 10-6, which exceeded the unit risk of 10-6. The LCR values presented here were mainly influenced by accumulation mode PAHs which came from biomass burning (24 %), coal combustion (25 %), and vehicular emission (27 %). The present study provides us with a mechanistic understanding of the particle size distribution of PAHs and their transport in the human respiratory system, which can help develop better source control strategies.

  9. Sources and environmental processes of polycyclic aromatic hydrocarbons and mercury along a southern slope of the Central Himalayas, Nepal.

    Science.gov (United States)

    Pokhrel, Balram; Gong, Ping; Wang, Xiaoping; Gao, Shaopeng; Wang, Chuanfei; Yao, Tandong

    2016-07-01

    Semi-volatile pollutants can undergo long-range atmospheric transport from low-altitude source regions to high-altitude regions and then accumulate in surface matrices (soil and plants). The Himalayas is the highest mountain range worldwide, but there have been limited studies on the source, transport, and deposition of polycyclic aromatic hydrocarbons (PAHs) and mercury (Hg) in the region. In this study, atmospheric PAHs, and the PAHs and Hg in soil and foliage were determined along a transect on a southern slope of the Himalayas, Nepal. The study showed anthropogenic emissions of PAHs and Hg occurred in the lowland areas of Nepal, and upslope transport to the high-altitude regions happened for both pollutants. During the upslope transport, forest filter effect and snow scavenging may be the important factors that enhance the deposition of PAHs, contributing to the negative pattern between concentrations of PAHs and altitudes. On the contrary, more Hg accumulated in the high Himalayas, relating to the enhanced deposition in the high altitude caused by the higher input from upper atmosphere. Graphical abstract Distribution and environmental processes of PAHs and Hg along the southern slope of Himalayan mountain. PMID:27032636

  10. Rotation-vibration interactions in the spectra of polycyclic aromatic hydrocarbons: Quinoline as a test-case species.

    Science.gov (United States)

    Pirali, O; Kisiel, Z; Goubet, M; Gruet, S; Martin-Drumel, M A; Cuisset, A; Hindle, F; Mouret, G

    2015-03-14

    Polycyclic aromatic hydrocarbons (PAHs) are highly relevant for astrophysics as possible, though controversial, carriers of the unidentified infrared emission bands that are observed in a number of different astronomical objects. In support of radio-astronomical observations, high resolution laboratory spectroscopy has already provided the rotational spectra in the vibrational ground state of several molecules of this type, although the rotational study of their dense infrared (IR) bands has only recently become possible using a limited number of experimental set-ups. To date, all of the rotationally resolved data have concerned unperturbed spectra. We presently report the results of a high resolution study of the three lowest vibrational states of quinoline C9H7N, an N-bearing naphthalene derivative. While the pure rotational ground state spectrum of quinoline is unperturbed, severe complications appear in the spectra of the ν45 and ν44 vibrational modes (located at about 168 cm(-1) and 178 cm(-1), respectively). In order to study these effects in detail, we employed three different and complementary experimental techniques: Fourier-transform microwave spectroscopy, millimeter-wave spectroscopy, and Fourier-transform far-infrared spectroscopy with a synchrotron radiation source. Due to the high density of states in the IR spectra of molecules as large as PAHs, perturbations in the rotational spectra of excited states should be ubiquitous. Our study identifies for the first time this effect and provides some insights into an appropriate treatment of such perturbations. PMID:25770543

  11. Concentration level and distribution of polycyclic aromatic hydrocarbons in soil and grass around Mt.Qomolangma,China

    Institute of Scientific and Technical Information of China (English)

    WANG XiaoPing; YAO TanDong; CONG ZhiYuan; YAN XinLiang; KANG ShiChang; ZHANG Yong

    2007-01-01

    High mountains may serve as a condenser for persistent organic pollutants.In the present study,soil and grass samples from Mt.Qomolangma region,China were collected from 4600 to 5620 m a.s.l and were analyzed for polycyclic aromatic hydrocarbons (PAHs) to determine if they are concentrated at colder,more elevated sites and to evaluate their possible resources and fractionation.The total PAHs Concentration in soil samples was<600 ng g-1,the critical value to differentiate PAHs levels in remote and urban regions.This implied the PAHs levels at Mt.Qomolangma are relatively low and what one might expect in such a remote region of the world.These low values may represent a soil background for mid-latitude Northern Hemisphere soils away from the direct influence of an anthropogenic source.As for the distribution pattern,the low molecular weight PAHs were prone to accumulate at higher altitude,while the high molecular weight PAHs inversely related or unrelated with elevation.Based on high concentration of phenanthrene at elevated sample site and the ratios of individual PAHs,we deduced that home-heating combustion and vehicle emission may result in the constitution trait of PAHs in this mountain region.Monsoon traveling over India,Pakistan and other countries with dense population may carry contaminant to Mt.Qomolangma region.

  12. Unravelling airborne polycyclic aromatic hydrocarbons (PAHs in southern China using tree-rings of 100-yr old Pinus Kwangtungensis

    Directory of Open Access Journals (Sweden)

    L. B. Huang

    2011-10-01

    Full Text Available Reliable perennial biomonitoring of airborne polycyclic aromatic hydrocarbons (PAHs is urgently necessary to detect long-term impacts of anthropogenic emission, in response to industrial policies and combustion technology adoption. One hundred records of airborne PAHs were novelly demonstrated by analyzing the tree-rings of Kwangtung pine (Pinus kwangtungensis formed from 1883 to 2007 at Naling Mountains of southern China. The total concentrations of PAHs (∑PAHs detected in the tree xylem did not progressively increase against the time. Temporal increase of high molecular-weight PAHs (HMW-PAHs coincided well to the historical-socioeconomic status in China, suggesting HMW-PAHs in old trees growing at high mountains were more indicative of regionally historical changes in airborne PAHs compared with ∑PAHs. Compositional analysis indicated airborne PAHs absorbed and accumulated in tree tissues were pyrogenic origination. Principal component analysis revealed PAHs inputs were quite historically diversiform and unevenly distributed in the atmosphere of Nanling Mountains of southern China. Dendroanalysis of old trees grown at geographically sink locations could be a useful biomonitoring technique for unravelling historical changes in PAHs composition and intensity in the atmosphere, in relation to regional industrial development and fuel consumptions.

  13. Far-Infrared Spectroscopy of Cationic Polycyclic Aromatic Hydrocarbons: Zero Kinetic Energy Photoelectron Spectroscopy of Pentacene Vaporized from Laser Desorption

    CERN Document Server

    Zhang, J; Pei, L; Kong, W; Li, Aigen

    2012-01-01

    The distinctive set of infrared (IR) emission bands at 3.3, 6.2, 7.7, 8.6, and 11.3{\\mu}m are ubiquitously seen in a wide variety of astrophysical environments. They are generally attributed to polycyclic aromatic hydrocarbon (PAH) molecules. However, not a single PAH species has yet been identified in space, as the mid-IR vibrational bands are mostly representative of functional groups and thus do not allow one to fingerprint individual PAH molecules. In contrast, the far-IR (FIR) bands are sensitive to the skeletal characteristics of a molecule, hence they are important for chemical identification of unknown species. With an aim to offer laboratory astrophysical data for the Herschel Space Observatory, Stratospheric Observatory for Infrared Astronomy, and similar future space missions, in this work we report neutral and cation FIR spectroscopy of pentacene (C_22H_14), a five-ring PAH molecule. We report three IR active modes of cationic pentacene at 53.3, 84.8, and 266{\\mu}m that may be detectable by space ...

  14. Far infrared (terahertz) spectroscopy of a series of polycyclic aromatic hydrocarbons and application to structure interpretation of asphaltenes and related compounds

    Science.gov (United States)

    Cataldo, Franco; Angelini, Giancarlo; García-Hernández, D. A.; Manchado, Arturo

    2013-07-01

    A series of 33 different polycyclic aromatic hydrocarbons (PAHs) were studied by far infrared spectroscopy (terahertz spectroscopy) in the spectral range comprised between 600 and 50 cm-1. In addition to common PAHs like naphthalene, anthracene, phenanthrene, fluoranthene, picene, pyrene, benzo[α]pyrene, and perylene, also quite unusual PAHs were studied like tetracene, pentacene, acenaphtene, acenaphtylene, triphenylene, and decacyclene. A series of alkylated naphthalenes and anthracenes were studied as well as methypyrene. Partially or totally hydrogenated PAHs were also object of the present investigation, ranging from tetrahydronaphthalene (tetralin) to decahydronaphthalene (decalin), 9,10-dihydroanthracene, 9,10-dihydrophenanthrene, hexahydropyrene, and dodecahydrotriphenylene. Finally, the large and quite rare PAHs coronene, quaterrylene, hexabenzocoronene, and dicoronylene were studied by far infrared spectroscopy. The resulting reference spectra were used in the interpretation of the chemical structure of asphaltenes (as extracted from a heavy petroleum fraction and from bitumen), the chemical structures of other petroleum fractions known as DAE (distillate aromatic extract) and RAE (residual aromatic extract), and a possible interpretation of components of the chemical structure of anthracite coal. Asphaltenes, heavy petroleum fractions, and coal were proposed as model compounds for the interpretation of the emission spectra of certain proto-planetary nebulae (PPNe) with a good matching in the mid infrared between the band pattern of the PPNe emission spectra and the spectra of these oil fractions or coal. Although this study was finalized in an astrochemical context, it may find application also in the petroleum and coal chemistry.

  15. Far infrared (terahertz) spectroscopy of a series of polycyclic aromatic hydrocarbons and application to structure interpretation of asphaltenes and related compounds.

    Science.gov (United States)

    Cataldo, Franco; Angelini, Giancarlo; García-Hernández, D Aníbal; Manchado, Arturo

    2013-07-01

    A series of 33 different polycyclic aromatic hydrocarbons (PAHs) were studied by far infrared spectroscopy (terahertz spectroscopy) in the spectral range comprised between 600 and 50 cm(-1). In addition to common PAHs like naphthalene, anthracene, phenanthrene, fluoranthene, picene, pyrene, benzo[α]pyrene, and perylene, also quite unusual PAHs were studied like tetracene, pentacene, acenaphtene, acenaphtylene, triphenylene, and decacyclene. A series of alkylated naphthalenes and anthracenes were studied as well as methypyrene. Partially or totally hydrogenated PAHs were also object of the present investigation, ranging from tetrahydronaphthalene (tetralin) to decahydronaphthalene (decalin), 9,10-dihydroanthracene, 9,10-dihydrophenanthrene, hexahydropyrene, and dodecahydrotriphenylene. Finally, the large and quite rare PAHs coronene, quaterrylene, hexabenzocoronene, and dicoronylene were studied by far infrared spectroscopy. The resulting reference spectra were used in the interpretation of the chemical structure of asphaltenes (as extracted from a heavy petroleum fraction and from bitumen), the chemical structures of other petroleum fractions known as DAE (distillate aromatic extract) and RAE (residual aromatic extract), and a possible interpretation of components of the chemical structure of anthracite coal. Asphaltenes, heavy petroleum fractions, and coal were proposed as model compounds for the interpretation of the emission spectra of certain proto-planetary nebulae (PPNe) with a good matching in the mid infrared between the band pattern of the PPNe emission spectra and the spectra of these oil fractions or coal. Although this study was finalized in an astrochemical context, it may find application also in the petroleum and coal chemistry.

  16. Effects of methyl group on aromatic hydrocarbons on the nanostructures and oxidative reactivity of combustion-generated soot

    KAUST Repository

    Guerrero Peña, Gerardo D.J.

    2016-07-23

    The substituted and unsubstituted aromatic hydrocarbons, present in transportation fuels such as gasoline and diesel, are thought to be responsible for most of the soot particles produced during their combustion. However, the effects of the substituted alkyl groups on the aromatic hydrocarbons on their sooting tendencies, and on the physical and chemical properties of soot produced from them are not well understood. In this work, the effect of the presence of methyl groups on aromatic hydrocarbons on their sooting propensity, and on the oxidative reactivity, morphology, and chemical composition of soot generated from them in diffusion flames is studied using benzene, toluene, and m-xylene as fuels. Several experimental techniques including high resolution transmission electron microscopy and X-ray diffraction are used to identify the morphological changes in soot, whereas the elemental and thermo-gravimetric analyses, electron energy loss spectroscopy, and Fourier transform infrared spectroscopy are used to study the changes in its chemical properties and reactivity. The activation energies for soot oxidation are calculated at different conversion levels, and a trend in the reactivity of soots from benzene, toluene and m-xylene is reported. It is observed that the sizes of primary particles and graphene-like sheets, and the concentrations of aliphatics and oxygenated groups in soot particles decreased with the addition of methyl group(s) on the aromatic ring. The physicochemical changes in soot are found to support the oxidative reactivity trends. © 2016 The Combustion Institute

  17. Piston ring lubrication and hydrocarbon emissions from internal combustion engines

    Energy Technology Data Exchange (ETDEWEB)

    Froelund, K.

    1997-11-01

    Is it the intention with this project to improve the existing hydrocarbon emission model at the Institute by combining it with a model for predicting the piston ring lubrication. The piston ring lubrication model should be experimentally verified to ensure the validity of the model. The following items were the objectives of the current study: Develop a piston ring lubrication model. This implies the development of a ring-pack gas flow model; Examine the response of the piston ring lubrication model to changing engineer conditions. Especially, it would be interesting to look at the engine warm-up phase since this is the phase where the engine-out emissions are highest and where the commonly used three way catalyst is not capable of converting the engine-out emissions, thereby leading the engine-out emissions directly out in to the environment with the exhaust gases; In order to verify the piston ring lubrication model the lubricant distribution on the cylinder liner should be investigated experimentally. Here again it would be of great interesting to look at the engine warm-up phase; The piston ring lubrication model should be adjusted for application together with the new hydrocarbon emission model for SI-engines at the Institute in order to increase the accuracy of the latter; The piston ring lubrication model could be used for describing the transport of PAH`s in diesel engines. (EG)

  18. Field effect transistors based on polycyclic aromatic hydrocarbons for the detection and classification of volatile organic compounds.

    Science.gov (United States)

    Bayn, Alona; Feng, Xinliang; Müllen, Klaus; Haick, Hossam

    2013-04-24

    We show that polycyclic aromatic hydrocarbon (PAH) based field effect transistor (FET) arrays can serve as excellent chemical sensors for the detection of volatile organic compounds (VOCs) under confounding humidity conditions. Using these sensors, w/o complementary pattern recognition methods, we study the ability of PAH-FET(s) to: (i) discriminate between aromatic and non-aromatic VOCs; (ii) distinguish polar and non-polar non-aromatic compounds; and to (iii) identify specific VOCs within the subgroups (i.e., aromatic compounds, polar non-aromatic compounds, non-polar non-aromatic compounds). We further study the effect of water vapor on the sensor array's discriminative ability and derive patterns that are stable when exposed to different constant values of background humidity. Patterns based on different independent electronic features from an array of PAH-FETs may bring us one step closer to creating a unique fingerprint for individual VOCs in real-world applications in atmospheres with varying levels of humidity.

  19. Effect of the Structure of Cations and Anions of Ionic Liquids on Separation of Aromatics from Hydrocarbon Mixtures

    Institute of Scientific and Technical Information of China (English)

    Liu Yansheng; Zhang Zhongxin; Zhang Guofu; Liu Zhichang; Hu Yufeng; Shi Quan; Ji Dejun

    2006-01-01

    The effects of the structure of typical cations and anions of ionic liquids on the separation of benzene and toluene from aromatic/paraffin mixtures were studied. The results showed that the corresponding separation factors were considerably larger than those of the traditional solvents (Benzene+Hexane+sulfolane), and that the ionic liquids could be used as novel solvents for the separation of aromatics from hydrocarbon mixtures. The key parameters governing the ability of ionic liquids for separating aromatics from hydrocarbon sources were investigated. It was found that the effectiveness of the ionic liquids, based on the same anion, changed in the cation order of [BIqu]+< [BPy]+< [BMIM]+. The selectivity of the ionic liquid toward aromatics decreased apparently with the increasing length of the substituted alkyl chain of its cationic head ring. The separation factors, based on the same cation, changed in the anion order of [Tf2N]-<[PF6]-<[BF4]-<[C2H5SO4]-. The solubilities of the aromatics were greater in the ionic liquids based on the former three anions than that in the ionic liquids involving [C2H5SO4]-.

  20. From Interstellar Polycyclic Aromatic Hydrocarbons and Ice to the Origin of Life

    Science.gov (United States)

    Allamandola, Louis

    2004-01-01

    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. Twenty years ago the composition of interstellar dust was largely guessed at, the concept of ices in dense molecular clouds ignored, and the notion of large, abundant, gas phase, carbon rich molecules widespread throughout the interstellar medium (ISM) considered impossible. Today the composition of dust in the diffuse ISM is reasonably well constrained to cold refractory materials comprised of amorphous and crystalline silicates mixed with an amorphous carbonaceous material containing aromatic structural units and short, branched aliphatic chains. In the dense ISM, the birthplace of stars and planets, these cold dust particles are coated with mixed molecular ices whose composition is very well constrained. Lastly, the signature of carbon-rich polycyclic aromatic hydrocarbons (PAHs), shockingly large molecules by early interstellar chemistry standards, is widespread throughout the Universe. The first part of this talk will describe how infrared studies of interstellar space, combined with laboratory simulations, have revealed the composition of interstellar ices (the building blocks of comets) and the high abundance and nature of interstellar PAHs. The laboratory database has now enabled us to gain insight into the identities, abundances, and physical state of many interstellar materials. Within a dense molecular cloud, and especially in the presolar nebula, the materials frozen into the interstellar/precometary ices are photoprocessed by ultraviolet light and produce more complex molecules. The remainder of the presentation will focus on the photochemical evolution of these materials and the possible role of these compounds on the to the carbonaceous components of micrometeorites, they are likely to have been important sources of complex materials on the early