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1

Study of respirable suspended particulates and polycyclic aromatic hydrocarbons in indoor and outdoor air.  

PubMed

To study the concentration change of respirable suspended particulate (RSP) in indoor and outdoor air environment, a new portable sampler (AND-sampler) was made. The sampler could collect particles above 10 microns, 2 to 10 microns, and below 2 microns in aerodynamic diameter separately. The relationship between the airborne particulate concentration in indoor and outdoor air environment varied with the aerodynamic diameter of the particles. The concentration of RSP in indoor air environment increased in proportion to that in outdoor environment. Polycyclic aromatic hydrocarbons (PAH) concentration in airborne particulate also varies with the aerodynamic diameter of the particles. Fine particles below 2 microns in aerodynamic diameter contains high concentration of PAH. The PAH concentration in indoor air environment increases in proportion to that in outdoor air. PMID:1723546

Ando, M; Tamura, K

1991-01-01

2

Concentrations and sources of polycyclic aromatic hydrocarbons in indoor dust in China.  

PubMed

Indoor dust samples were collected across China in the winter of 2010 from 45 private domiciles and 36 public buildings. 16 polycyclic aromatic hydrocarbons (PAHs) were determined by GC-MS. Total concentrations of PAHs ranged from 1.00?g/g to 470?g/g with a mean value of 30.9?g/g. High-molecular weight (HMW) PAHs (4 to 6 rings) are the predominant PAHs found in indoor dust, accounting for 68% of the total PAH concentration in private domiciles, and 84.6% in public buildings. Traffic conditions and cooking methods were the two key factors controlling PAH levels, especially for coal combustion and vehicular traffic emission sources. A significant positive correlation was observed between PAH concentrations in indoor dust and based on location (latitude and longitude). The latitudinal distribution indicated a higher usage of coal for heating in Northern China than in Southern China. The longitudinal distribution indicated that the usage of oil and mineral fuels as well as economic development and population density increased from West China to East China. In addition, diagnostic ratios and principal component analysis (PCA) were used to explore source apportion, as indicated in both the pyrogenic and petrogenic sources of PAHs in indoor dust in China. Furthermore, the BaP equivalent was applied to assess the carcinogenic risk of PAHs, which also indicated that traffic emissions and coal combustion were the two major contributions to carcinogenic risk of PAHs in indoor dust in China. PMID:24602396

Qi, Hong; Li, Wen-Long; Zhu, Ning-Zheng; Ma, Wan-Li; Liu, Li-Yan; Zhang, Feng; Li, Yi-Fan

2014-09-01

3

[Study on size distribution of 8 polycylic aromatic hydrocarbons in airborne suspended particulates indoor and outdoor].  

PubMed

During Jan. 20-27, 1992, the size distribution of 8 polycyclic aromatic hydrocarbons (PAHs) in airborne suspended particulates in Tokyo, Japan was studied. The results showed that PAHs, 79.0%-94.5% in indoor air and 65.4%-90.4% in outdoor air, were associated with aerodynamic diameter less than 2.5 microns particles. The contents of these PAHs in indoor air were: pyrene (Py) 1.98, benzo (a) anthracene (BaA) 0.92, benzo (k) fluoranthene (BkF) 0.91, benzo (a) pyrene (BaP) 2.13, dibenzo (a,h) anthracene (dBahA) 0.30, benzo (b) chrysene (BbC) 0.15, benzo (g,h,i) perylene (BghiP) 2.56, dibenzo (a,e) pyrene (dBaeP) 0.23 ng/m3 and in outdoor air 3.93, 2.01, 1.41, 2.91, 0.40, 0.19, 3.65 and 0.30 ng/m3 respectively. The indoor/outdoor ratios for these PAHs ranged from 0.46 to 0.79. These PAHs contents were significantly correlative with one another and so were between the PAHs contents and the concentrations of airborne particulates both indoor and outdoor (the correlation coefficients ranged from 0.774 to 0.999). The PAHs contents (excluding Py) and the concentrations of airborne particulates between outdoor and indoor samples also correlated well with each other (correlation coefficients ranged from 0.821 to 0.944). PMID:7744392

Sun, C; Tanabe, K; Koyano, M; Yang, Z; Li, Y; Zhang, J

1994-12-01

4

IDENTIFICATION AND QUANTIFICATION OF NITROPOLYNUCLEAR AROMATIC HYDROCARBONS IN AMBIENT AND INDOOR AIR PARTICULATE SAMPLES  

EPA Science Inventory

Polynuclear aromatic hydrocarbons (PAH) and nitro-substituted polynuclear aromatic hydrocarbons (NO2-PAH) have been identified in organic extracts of ambient air particulate matter. Many of the identified PAH and NO2-PAH are potent carcinogens and/or mutagens. Therefore the deter...

5

Emission of oxygenated polycyclic aromatic hydrocarbons from indoor solid fuel combustion.  

PubMed

Indoor solid fuel combustion is a dominant source of polycyclic aromatic hydrocarbons (PAHs) and oxygenated PAHs (OPAHs) and the latter are believed to be more toxic than the former. However, there is limited quantitative information on the emissions of OPAHs from solid fuel combustion. In this study, emission factors of OPAHs (EF(OPAH)) for nine commonly used crop residues and five coals burnt in typical residential stoves widely used in rural China were measured under simulated kitchen conditions. The total EF(OPAH) ranged from 2.8 ± 0.2 to 8.1 ± 2.2 mg/kg for tested crop residues and from 0.043 to 71 mg/kg for various coals and 9-fluorenone was the most abundant specie. The EF(OPAH) for indoor crop residue burning were 1-2 orders of magnitude higher than those from open burning, and they were affected by fuel properties and combustion conditions, like moisture and combustion efficiency. For both crop residues and coals, significantly positive correlations were found between EFs for the individual OPAHs and the parent PAHs. An oxygenation rate, R(o), was defined as the ratio of the EFs between the oxygenated and parent PAH species to describe the formation potential of OPAHs. For the studied OPAH/PAH pairs, mean R(o) values were 0.16-0.89 for crop residues and 0.03-0.25 for coals. R(o) for crop residues burned in the cooking stove were much higher than those for open burning and much lower than those in ambient air, indicating the influence of secondary formation of OPAH and loss of PAHs. In comparison with parent PAHs, OPAHs showed a higher tendency to be associated with particulate matter (PM), especially fine PM, and the dominate size ranges were 0.7-2.1 ?m for crop residues and high caking coals and <0.7 ?m for the tested low caking briquettes. PMID:21375317

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

2011-04-15

6

EVALUATION OF SAMPLING AND ANALYTICAL METHODS FOR NICOTINE AND POLYNUCLEAR AROMATIC HYDROCARBON IN INDOOR AIR  

EPA Science Inventory

The objective of the project was to evaluate a potential collection medium, XAD-4 resin, for collecting nicotine and polynuclear aromatic hydrocarbon (PAH) and to determine whether one collection system and one analytical method will allow quantification of both compound classes ...

7

Polycyclic aromatic hydrocarbons and their derivatives in indoor and outdoor air in an eight-home study  

SciTech Connect

A pilot field study was performed in Columbus, Ohio during the winter of 1986-1987. The objectives were to determine the feasibility of the use of a newly developed quiet sampler in indoor air sampling for particles and semivolatile organic compounds (SVOCs), and to estimate the range of concentrations of polycyclic aromatic hydrocarbons (PAH), PAH derivatives, and nicotine in air in selected residences. Eight homes were chosen for sampling on the basis of these characteristics: electric/gas heat, electric/gas cookstove, and absence/presence of environmental tobaccos smoke (ETS). Fifteen PAH, five nitro-PAH, five oxygenated PAH, and three nitrogen heterocyclic compounds were determined. The sampler performed well and met all design expectations.

Chuang, J.C.; Mack, G.A.; Kuhlman, M.R.; Wilson, N.K.

1991-01-01

8

Polycyclic aromatic hydrocarbons in indoor air and environmental tobacco smoke measured with a new integrated organic vapor-particle sampler  

SciTech Connect

To avoid sampling artifacts, an integrated organic vapor-particle sampler (IOVPS) has been developed for polycyclic aromatic hydrocarbons (PAH). The ICIVPS is based on an XAD-4-coated annular denuder which strips gas phase species from the air stream before collection of particles on a filter. A second denuder downstream of the filter collects species desorbed ( blown off'') the particles during sampling. PAH are determined in extracts of both denuders and the filter. For indoor air with no combustion sources, the gas-phase concentrations of several semivolatile PAH measured with the IOVPS averaged about half of those found with a conventional filter-sorbent bed sampler. For envirorunental tobacco smoke the gas-phase concentrations of the same PAH from the IOVPS averaged 70% of those found with the sorbent bed sampler. Particulate-phase concentrations were correspondingly higher with the IOVPS, but measurable blow off' semivolatile PAH occurred.

Gundel, L.A.; Daisey, J.M.; Mahanama, K.R.R.; Lee, V.C. (Lawrence Berkeley Lab., CA (United States)); Stevens, R.K. (Environmental Protection Agency, Research Triangle Park, NC (United States). Atmospheric Research and Exposure Assessment Lab.)

1993-01-01

9

EVALUATION OF A METHOD FOR SAMPLING AND ANALYSIS OF NICOTINE AND POLYNUCLEAR AROMATIC HYDROCARBONS IN INDOOR AIR  

EPA Science Inventory

A study was performed to determine whether one sampling system and one analytical method can be used to measure both polynuclear aromatic hydrocarbons (PAH) and nicotine. he PAH collection efficiencies for both XAD-2 and XAD-4 adsorbents are very similar, but the nicotine collect...

10

Population inhalation exposure to polycyclic aromatic hydrocarbons and associated lung cancer risk in Beijing region: Contributions of indoor and outdoor sources and exposures  

NASA Astrophysics Data System (ADS)

Polycyclic aromatic hydrocarbons (PAHs) are among the most toxic air pollutants in China. Efforts in assessing population inhalation exposure to PAHs, and its contribution to lung cancer risk for Chinese residents, have been limited due to insufficient data on measured indoor concentrations. A mass-balance model to predict indoor PAH concentrations was developed, along with estimated exposures and attributable lung cancer risks for residents in the Beijing region in 2006, with a 2-stage Monte Carlo simulation framework. The exposures and risks were split into three parts, based on the sources and places of exposure, to estimate the contributions of indoor and outdoor PAH sources and exposures, in order to better understand the source and place pattern of PAH exposure. PAHs bring considerable lung cancer risk to the population of Beijing region. The population attributable fraction (PAF) of lung cancer for Beijing's overall population is 2.99% [95% confidence interval (CI): 1.71%-4.26%]. Median contribution of indoor exposure to outdoor-originated PAHs (OUT-in) is 78% (CI: 73%-81%) in the overall population, for 97% (CI: 94%-99%) of whom OUT-in is the largest contributor. Rural residents are facing considerable exposure to indoor-originated PAHs (IN-in), which dominates the total exposure in 12% (CI: 2%-24%) of the rural population. This model framework could be used in quantitative comparison of different interventions on exposure to PAHs as well as other airborne pollutants.

Zhou, Bin; Zhao, Bin

2012-12-01

11

Carcinogenic potential, levels and sources of polycyclic aromatic hydrocarbon mixtures in indoor and outdoor environments and their implications for air quality standards.  

PubMed

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, when recommending their respective guidelines for PAHs in outdoor air. The aim of this research is to compare the concentrations and relative abundance of individual PAH and their contribution to the overall carcinogenic potential of the PAH mixture in indoor and outdoor environments to assess the suitability of the UK air quality standard derived for outdoor air for use as a guideline for indoor environments. Samples were collected onto filters using active sampling in different indoor and outdoor microenvironments. The ratio of individual compounds to BaP, the BaP equivalent concentrations and the percentage contribution of each individual compound to the total carcinogenic potential of the PAH mixture were calculated. Mean concentrations were generally lower indoors (BaP=0.10 ng/m(3)) than outdoors (BaP=0.19 ng/m(3)), with the exception of indoor environments with wood burners (BaP=2.4 ng/m(3)) or ETS (BaP=0.6 ng/m(3)). The ratio of individual PAHs to BaP showed no significant differences between indoors (e.g. DahA/BaP=0.27) and outdoors (DahA/BaP=0.31). The relative contribution of BaP to the PAH overall carcinogenic potency is similar indoors (49%), outdoors (54%) and in the smelter environment (48%) used by EPAQS to derive the UK Air Quality Standard for ambient air. These results suggest the suitability of BaP as a marker for the carcinogenic potential of the PAH mixture irrespective of the environment. Despite small differences in PAH mixture composition indoors and outdoors, the level of protection afforded by the present EPAQS standard is likely to be similar whether it is applied to indoor or outdoor air. PMID:21146218

Delgado-Saborit, Juana Maria; Stark, Christopher; Harrison, Roy M

2011-02-01

12

Polycyclic aromatic hydrocarbons in indoor air and environmental tobacco smoke measured with a new integrated organic vapor-particle sampler. Revision  

SciTech Connect

To avoid sampling artifacts, an integrated organic vapor-particle sampler (IOVPS) has been developed for polycyclic aromatic hydrocarbons (PAH). The ICIVPS is based on an XAD-4-coated annular denuder which strips gas phase species from the air stream before collection of particles on a filter. A second denuder downstream of the filter collects species desorbed (``blown off``) the particles during sampling. PAH are determined in extracts of both denuders and the filter. For indoor air with no combustion sources, the gas-phase concentrations of several semivolatile PAH measured with the IOVPS averaged about half of those found with a conventional filter-sorbent bed sampler. For envirorunental tobacco smoke the gas-phase concentrations of the same PAH from the IOVPS averaged 70% of those found with the sorbent bed sampler. Particulate-phase concentrations were correspondingly higher with the IOVPS, but measurable ``blow off` semivolatile PAH occurred.

Gundel, L.A.; Daisey, J.M.; Mahanama, K.R.R.; Lee, V.C. [Lawrence Berkeley Lab., CA (United States); Stevens, R.K. [Environmental Protection Agency, Research Triangle Park, NC (United States). Atmospheric Research and Exposure Assessment Lab.

1993-01-01

13

Biodegradation of polycyclic aromatic hydrocarbons  

Microsoft Academic Search

The intent of this review is to provide an outline of the microbial degradation of polycyclic aromatic hydrocarbons. A catabolically diverse microbial community, consisting of bacteria, fungi and algae, metabolizes aromatic compounds. Molecular oxygen is essential for the initial hydroxylation of polycyclic aromatic hydrocarbons by microorganisms. In contrast to bacteria, filamentous fungi use hydroxylation as a prelude to detoxification rather

Carl E. Cerniglia

1992-01-01

14

A wintertime study of polycyclic aromatic hydrocarbons (PAHs) in indoor and outdoor air in a big student residence in Algiers, Algeria.  

PubMed

The wintertime concentrations and diel cycles of n-alkanes and polycyclic aromatic hydrocarbons (PAHs) associated to atmospheric particulate matter with aerodynamic diameter lesser than 10 ?m were determined at the biggest student residence in Algeria located in Bab-Ezzouar, 15 km southeast from Algiers city area. Samplings were carried out from December 2009 to March 2010, and organic compounds were characterized using gas chromatography coupled with mass spectrometric detection. Volatile PAHs were also monitored inside some student residence rooms in order to evaluate the impact of indoor air pollution to student health. For the sake of comparison, aerial concentrations of n-alkanes and PAHs were determined in parallel in the Oued Smar industrial zone and two suburban areas, all located in Algiers. Total concentrations recorded in CUB1 student residence ranged from 101 to 204 ng?m(-3) for n-alkanes and from 8 to 87 ng?m(-3) for PAHs. Diel cycles have shown that, while concentrations of n-alkanes peaked at morning and afternoon-evening and dropped at night, those of PAHs exhibited higher levels at morning and night and lower levels at afternoon-evening, likely due to the reactivity of some PAHs. As expected, the indoor levels of PAHs were larger than in the outdoor of the student residence and were of serious health concern. Overall, the concentrations of n-alkanes and PAHs were as high as those observed in the industrial zone and higher than the two suburban sites. PMID:23314704

Khedidji, Sidali; Ladji, Riad; Yassaa, Noureddine

2013-07-01

15

Effects of heating season on residential indoor and outdoor polycyclic aromatic hydrocarbons, black carbon, and particulate matter in an urban birth cohort  

NASA Astrophysics Data System (ADS)

Exposure to air pollutants has been associated with adverse health effects. However, analyses of the effects of season and ambient parameters such as ozone have not been fully conducted. Residential indoor and outdoor air levels of polycyclic aromatic hydrocarbons (PAH), black carbon (measured as absorption coefficient [Abs]), and fine particulate matter <2.5 ?m (PM) 2.5 were measured over two-weeks in a cohort of 5-6 year old children ( n = 334) living in New York City's Northern Manhattan and the Bronx between October 2005 and April 2010. The objectives were to: 1) characterize seasonal changes in indoor and outdoor levels and indoor/outdoor (I/O) ratios of PAH (gas + particulate phase; dichotomized into ? 8PAH semivolatile (MW 178-206), and ? 8PAH nonvolatile (MW 228-278)), Abs, and PM 2.5; and 2) assess the relationship between PAH and ozone. Results showed that heating compared to nonheating season was associated with greater ? 8PAH nonvolatile ( p < 0.001) and Abs ( p < 0.05), and lower levels of ? 8PAH semivolatile ( p < 0.001). In addition, the heating season was associated with lower I/O ratios of ? 8PAH nonvolatile and higher I/O ratios of ? 8PAH semivolatile ( p < 0.001) compared to the nonheating season. In outdoor air, ? 8PAH nonvolatile was correlated negatively with community-wide ozone concentration ( p < 0.001). Seasonal changes in emission sources, air exchanges, meteorological conditions and photochemical/chemical degradation reactions are discussed in relationship to the observed seasonal trends.

Jung, Kyung Hwa; Patel, Molini M.; Moors, Kathleen; Kinney, Patrick L.; Chillrud, Steven N.; Whyatt, Robin; Hoepner, Lori; Garfinkel, Robin; Yan, Beizhan; Ross, James; Camann, David; Perera, Frederica P.; Miller, Rachel L.

2010-11-01

16

Evaluation of sampling and analytical methods for nicotine and polynuclear aromatic hydrocarbon in indoor air. Final report, 1 February 1987-30 March 1987  

SciTech Connect

The objective of this project was to evaluate a potential collection medium, XAD-4 resin, for collecting nicotine and polynuclear aromatic hydrocarbon (PAH) and to determine whether one collection system and one analytical method will allow quantification of both compound classes in air. The extraction efficiency study was to determine the extraction method to quantitatively remove nicotine and PAH from XAD-4 resin. The results showed that a two-step Soxhlet extraction consisting of dichloromethane followed by ethyl acetate resulted in the best recoveries for both nicotine and PAH. In the sampling efficiency study, XAD-2 and XAD-4 resin were compared, in parallel, for collection of PAH and nicotine. Quartz fiber filters were placed upstream of both adsorbents to collect particles. Prior to sampling, both XAD-2 and XAD-4 traps were spiked with known amounts (2 microgram) of perdeuterated PAH and D3-nicotine. The experiments were performed with cigarette smoking and nonsmoking conditions. The spiked PAH were retained well in both adsorbents after exposure to more than 300 cu. m. of indoor air. The spiked XAD-4 resin gave higher recoveries for D3-nicotine than did the spiked XAD-2 resin. The collection efficiency for PAH for both adsorbents is very similar but higher levels of nicotine were collected on XAD-4 resin.

Chuang, J.C.; Kuhlman, M.R.; Hannan, S.W.; Bridges, C.

1987-11-01

17

Evaluation of exposure reduction to indoor air pollution in stove intervention projects in Peru by urinary biomonitoring of polycyclic aromatic hydrocarbon metabolites.  

PubMed

Burning biomass fuels such as wood on indoor open-pit stoves is common in developing regions. In such settings, exposure to harmful combustion products such as fine particulate matter (PM(2.5)), carbon monoxide (CO) and polycyclic aromatic hydrocarbons (PAHs) is of concern. We aimed to investigate if the replacement of open pit stoves by improved stoves equipped with a chimney would significantly reduce exposure to PAHs, PM(2.5) and CO. Two stove projects were evaluated in Peru. Program A was part of the Juntos National Program in which households built their own stoves using materials provided. In Program B, Barrick Gold Corporation hired a company to produce and install the stoves locally. A total of 30 and 27 homes participated in Program A and B, respectively. We collected personal and kitchen air samples, as well as morning urine samples from women tasked with cooking in the households before and after the installation of the improved stoves. Median levels of PM(2.5) and CO were significantly reduced in kitchen and personal air samples by 47-74% after the installation of the new stoves, while the median reduction of 10 urinary hydroxylate PAH metabolites (OH-PAHs) was 19%-52%. The observed OH-PAH concentration in this study was comparable or higher than the 95th percentile of the general U.S. population, even after the stove intervention, indicating a high overall exposure in this population. PMID:21524795

Li, Zheng; Sjödin, Andreas; Romanoff, Lovisa C; Horton, Kevin; Fitzgerald, Christopher L; Eppler, Adam; Aguilar-Villalobos, Manuel; Naeher, Luke P

2011-10-01

18

POLYCYCLIC AROMATIC HYDROCARBONS AND THEIR DERIVATIVES IN INDOOR AND OUTDOOR AIR IN AND EIGHT-HOME STUDY  

EPA Science Inventory

A pilot field study was performed in Columbus, Ohio during the winter of 1986/1987. he objectives were to determine the feasibility of the use of a newly developed quiet sampler in indoor air sampling for particles and semivolatile organic compounds (SVOCs), and to estimate the r...

19

Polycyclic Aromatic Hydrocarbon Structure Index.  

National Technical Information Service (NTIS)

The Structure Index presents a compilation of names, structures, and related data for 660 aromatic hydrocarbons. The publication consists of two parts: (1) chemical structures including ring numbering, name(s), Chemical Abstract Service (CAS) Registry num...

L. C. Sander S. A. Wise

1997-01-01

20

Polycyclic Aromatic Hydrocarbons  

NASA Technical Reports Server (NTRS)

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

Salama, Farid

2010-01-01

21

Exposure to halogenated hydrocarbons in the indoor environment.  

PubMed Central

The indoor environment has frequently been ignored as a significant source of exposure to air pollutants. To date there are a number of documented examples of levels of indoor air pollutants greatly exceeding those levels which commonly occur in the outdoor environment. Among these instances are airborne buildup of polynuclear aromatics and cadmium from cigarette smoke, lead from burning candles, and vinyl chloride from use of aerosols containing this substance as a propellant. These examples suggest that there may be additional sources of indoor air pollutants, particularly halogenated hydrocarbons from aerosol products, which have heretofore not been generally recognized as important. The present paper endeavors to review those instances where halogenated hydrocarbons in the indoor air environment may build up to concentrations of potential public health concern. These considerations may be especially relevant in future years as increasing efforts are being made to insulate buildings more efficiently as a means to conserve energy. The available data strongly suggest that halogenated hydrocarbons are an important class of air pollutants in the indoor environment and that their presence in the outdoor environment should also be carefully examined. In this regard, halogenated hydrocarbons in the outdoor environment may also contaminate indoor air spaces.

Bridbord, K; Brubaker, P E; Gay, B; French, J G

1975-01-01

22

AROMATIC HYDROCARBON DEGRADATION: A MOLECULAR APPROACH  

EPA Science Inventory

Aromatic hydrocarbons have a ubiquitous distribution in nature. he majority of these compounds are formed through the pyrolysis of organic matter. yrolysis at high temperatures leads to the information of unsubstituted polycyclic aromatic hydrocarbons (1). yrolysis at low tempera...

23

Carcinogenic potential, levels and sources of polycyclic aromatic hydrocarbon mixtures in indoor and outdoor environments and their implications for air quality standards  

Microsoft Academic Search

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, when recommending their respective guidelines for PAHs in outdoor air. The aim of this research is to compare the concentrations and relative abundance of individual PAH and

Juana Maria Delgado-Saborit; Christopher Stark; Roy M. Harrison

2011-01-01

24

Polycyclic Aromatic Hydrocarbon Structure Index  

NSDL National Science Digital Library

The Polycyclic Aromatic Hydrocarbon (PAH) Index, a special publication from the National Institute of Standards and Technology, provides the structures of a large number of PAHs. In addition to the structure, the Index lists other names for the compound, CAS number, molecular weight, length-to-breadth ratio, width, length, and thickness. Users can search the PAH Index via compound name and molecular weight, browse alphabetically, or scan cover to cover. An introduction to the Index is available in [.pdf] format.

Sander, Lane C.; Wise, Stephen A. (Stephen Albert), 1949-.

1997-01-01

25

Aromatic hydrocarbon degradation: A molecular approach  

SciTech Connect

Aromatic hydrocarbons have a ubiquitous distribution in nature. The majority of these compounds are formed through the pyrolysis of organic matter. Pyrolysis at high temperatures leads to the formation of unsubstituted polycyclic aromatic hydrocarbons. Pyrolysis at low temperatures, such as those at which crude petroleum is formed, leads to the formation of alkyl-substituted aromatic hydrocarbons. Many of these compounds are suspected carcinogens. Increased use of petrochemicals by modern society has increased the amount of aromatic hydrocarbons found in air and soil samples. It is not surprising then that due to the ubiquitous nature and increasing concentrations of aromatic hydrocarbons microorganisms can be found that have the ability to degrade these compounds. The varied mechanisms by which microorganisms utilize aromatic hydrocarbons as carbon and energy sources have been the focus of several reviews.

Zylstra, G.J.; Gibson, D.T.

1991-01-01

26

PHOTOREACTIVITY OF SELECTED AROMATIC HYDROCARBONS IN WATER  

EPA Science Inventory

Quantitative data concerning photoreactions of aromatic hydrocarbons were obtained in distilled water and several natural water samples. The reactions were studied at concentrations lower than the solubility limits of the aromatics, which in some cases were less than 1 microgram ...

27

Sedimentary polycyclic aromatic hydrocarbons: the historical record  

Microsoft Academic Search

Polycyclic aromatic hydrocarbons in three sections of a dated sediment core from Buzzards Bay, Massachusetts, have been analyzed by gas chromatographic mass spectrometry. This historical information suggests that sedimentary polycyclic aromatic hydrocarbons, at least at this location, result primarily from the anthropogenic combustion of fossil fuels.

R. A. Hites; R. E. LaFlamme; J. W. Farrington

1977-01-01

28

Birds and polycyclic aromatic hydrocarbons  

USGS Publications Warehouse

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.

Albers, P. H.

2006-01-01

29

Biological and environmental monitoring of exposure to airborne benzene and other aromatic hydrocarbons in Milan traffic wardens  

Microsoft Academic Search

Environmental and biological monitoring of airborne aromatic hydrocarbons has been performed in 20 policemen working as traffic wardens exposed to motor vehicle exhausts and in 19 peers employed as clerks. Airborne benzene toluene, ethylbenzene and xylene concentrations, measured during the workshift, resulted in significantly higher out door than indoor concentrations (benzene and related aromatic hydrocarbons mean values, respectively of 53

S. Fustinoni; M. Buratti; R. Giampiccolo; A. Colombi

1995-01-01

30

High temperature chemistry of aromatic hydrocarbons.  

National Technical Information Service (NTIS)

We have not only gained new insight into the mechanism and generality of Polycyclic Aromatic Hydrocarbon (PAH) thermal automerization reactions, we have also uncovered several new high temperature reactions and added a third dimension to our program by ap...

L. T. Scott

1991-01-01

31

Polycyclic Aromatic Hydrocarbon Analysis Round Robin Study.  

National Technical Information Service (NTIS)

The polycyclic aromatic hydrocarbon round robin study was conducted using an analytical procedure developed by IIT Research Institute. The method involves the fractionation of a representative diesel extract by high performance liquid chromatography (HPLC...

W. C. Eisenberg

1983-01-01

32

Infrared Spectra of Polycyclic Aromatic Hydrocarbons (PAHs)  

NASA Technical Reports Server (NTRS)

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

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

2000-01-01

33

Polycyclic aromatic hydrocarbons in gas and particulate phases of indoor environments influenced by tobacco smoke: Levels, phase distributions, and health risks  

NASA Astrophysics Data System (ADS)

As polycyclic aromatic hydrocarbons (PAHs) have a negative impact on human health due to their mutagenic and/or carcinogenic properties, the objective of this work was to study the influence of tobacco smoke on levels and phase distribution of PAHs and to evaluate the associated health risks. The air samples were collected at two homes; 18 PAHs (the 16 PAHs considered by U.S. EPA as priority pollutants, dibenzo[a,l]pyrene and benzo[j]fluoranthene) were determined in gas phase and associated with thoracic (PM 10) and respirable (PM 2.5) particles. At home influenced by tobacco smoke the total concentrations of 18 PAHs in air ranged from 28.3 to 106 ng m -3 (mean of 66.7 ± 25.4 ng m -3), ? PAHs being 95% higher than at the non-smoking one where the values ranged from 17.9 to 62.0 ng m -3 (mean of 34.5 ± 16.5 ng m -3). On average 74% and 78% of ? PAHs were present in gas phase at the smoking and non-smoking homes, respectively, demonstrating that adequate assessment of PAHs in air requires evaluation of PAHs in both gas and particulate phases. When influenced by tobacco smoke the health risks values were 3.5-3.6 times higher due to the exposure of PM 10. The values of lifetime lung cancer risks were 4.1 × 10 -3 and 1.7 × 10 -3 for the smoking and non-smoking homes, considerably exceeding the health-based guideline level at both homes also due to the contribution of outdoor traffic emissions. The results showed that evaluation of benzo[a]pyrene alone would probably underestimate the carcinogenic potential of the studied PAH mixtures; in total ten carcinogenic PAHs represented 36% and 32% of the gaseous ? PAHs and in particulate phase they accounted for 75% and 71% of ? PAHs at the smoking and non-smoking homes, respectively.

Castro, Dionísia; Slezakova, Klara; Delerue-Matos, Cristina; Alvim-Ferraz, Maria da Conceição; Morais, Simone; Pereira, Maria do Carmo

2011-04-01

34

Ethane to Aromatic Hydrocarbons: Past, Present, Future  

Microsoft Academic Search

Ranking high in the current challenges of catalysis, direct transformations of lower saturated hydrocarbons (alkanes) have been investigated for a long time. However, unsaturated hydrocarbons (e.g., aromatics and olefins) have always been the more important feedstocks to produce basic and intermediate chemicals because of their wide variety of possible reaction pathways. This article focuses on the conversion of one representative

ANKE HAGEN; FRANK ROESSNER

2000-01-01

35

Participant-Based Monitoring of Indoor and Outdoor Nitrogen Dioxide, Volatile Organic Compounds, and Polycyclic Aromatic Hydrocarbons among MICA-Air Households  

EPA Science Inventory

The Mechanistic Indicators of Childhood Asthma (MICA) study in Detroit, Michigan introduced a participant-based approach to reduce the resource burden associated with collection of indoor and outdoor residential air sampling data. A subset of participants designated as MICA-Air c...

36

Comparison of Polycyclic Aromatic Hydrocarbons and Nitropolycyclic Aromatic Hydrocarbons in Airborne and Automobile Exhaust Particulates  

Microsoft Academic Search

Polycyclic aromatic hydrocarbons (PAH) and nitropolycyclic aromatic hydrocarbons (NPAH) in airborne particulates collected simultaneously at downtown and suburban sites and in exhaust particulates from diesel and gasoline engine vehicles were determined. The mean concentrations of all compounds in the atmosphere were lower at the suburban site. The differences between the two sites were smaller in airborne particulates than in the

Kazuichi Hayakawa; Tsuyoshi Murahashi; Kazuhiko Akutsu; Tetsuo Kanda; Ning Tang; Hitoshi Kakimoto; Akira Toriba; Ryoichi Kizu

2000-01-01

37

Polycyclic Aromatic Hydrocarbons in Indoor Air and EnvironmentalTobacco Smoke Measured with a New Integrated Organic Vapor-ParticleSampler  

SciTech Connect

Sampling details. The novel aspect of the sampling equipment is the use of ground XAD-4 resin as a coating for annular denuders. Figure 1 shows a schematic diagram of one sampling configuration used for field testing the IOVPS in indoor air and ETS. Commercially available, single-channel glass denuders, 22 cm long, with a 1 mm annulus (University Research Glass, Carrboro, NC, USA were used with a Teflon- ) lined aluminum cyclone (cutoff 2.5 microns at 10 L mine ) preceding the first denuder. Three XAD-4-coated denuders were connected in series between the cyclone and a Teflon filter pack which contained a pre-extracted and pre-weighed Teflon-coated glass-fiber filter. (The three-denuder configuration was used for determining breakthrough of naphthalene and its methyl derivatives as a function of flow rate.) In some experiments, a coated denuder followed the filter pack. The parallel sorbent bed sampler used an aluminum open-face filter holder with a Teflon-coated glass-fiber filter, followed by a glass tube packed with 2.5 g cleaned XAD-4 resin. Flow rates, measured with a dry gas test meter, were 5, 10 and 20 L min-1 for field testing; sampling times varied from 3 to 22 hours. Indoor air with no combustion sources was sampled in an unoccupied room. Diluted sidestream smoke was sampled as a surrogate for ETS in an unventilated 20 m3 chamber at 5 L rnin-l for hour-long periods while a single-port smoking machine smoked 3 cigarettes. Ambient temperature varied between 22 and 26 C.

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

1993-01-01

38

Microbial Degradation of Aromatic Hydrocarbons in Marine Sediments.  

National Technical Information Service (NTIS)

This study examined how adsorption to marine sediments affects the bioavailability of aromatic hydrocarbons. Sediment slurries were used to study microbial mineralization of the aromatic hydrocarbons, phenanthrene and naphthalene, added at low concentrati...

J. F. Braddock Z. Richter

1998-01-01

39

STATUS ASSESSMENT OF TOXIC CHEMICALS: POLYNUCLEAR AROMATIC HYDROCARBONS  

EPA Science Inventory

This report identifies the origins, applications, environmental effects, and health effects of polynuclear aromatic hydrocarbons. Ways to reduce polynuclear aromatic hydrocarbons (PNA) emissions and problems associated with PNA derived effluents in the dye industry are discussed....

40

Detection of Polycyclic Aromatic Hydrocarbons (PAHs) in Human Breast Milk  

Microsoft Academic Search

Exposure to polycyclic aromatic hydrocarbons can result from numerous sources including dietary as well as environmental. Exposure to polycyclic aromatic hydrocarbons has been well-established through combustion sources, particularly coal-fired power plants, automobile and diesel exhaust emissions, and the burning of fossil fuels. In addition, exposure to polycyclic aromatic hydrocarbons occurs through the intake of tobacco smoke, both mainstream and sidestream,

S. Hunter; S. Myers; P. Radmacher; C. Eno

2010-01-01

41

On the aromatic stabilization of benzenoid hydrocarbons.  

PubMed

A general scheme for estimation of aromatic stabilization energies of benzenoid hydrocarbons based on selected topological features has been presented. The reactions have been applied to benzene, naphthalene, anthracene, phenanthrene, pyrene, tetracene, benz[a]anthracene, chrysene, [4]-helicene, anthanthrene and coronene. PMID:22962659

Ciesielski, Arkadiusz; Stepie?, Dorota K; Dobrowolski, Micha? A; Dobrzycki, ?ukasz; Cyra?ski, Micha? K

2012-10-18

42

Analysis of nitrated polycyclic aromatic hydrocarbons  

Microsoft Academic Search

Many nitrated polycyclic aromatic hydrocarbons (NPAH) that are present in low concentrations in the environment and in emission\\u000a sources have been shown to be mutagenic and\\/or carcinogenic. This paper reviews the current methods of analysis of these compounds\\u000a with the emphasis on NPAH measurements in ambient particulate matter samples.

Barbara Zielinska; Shar Samy

2006-01-01

43

Polynuclear aromatic hydrocarbons: Chemistry, characterization and carcinogenesis  

SciTech Connect

This book contains 75 selections. Some of the titles are: Polycyclic Aromatic Hydrocarbons in Cancer Research, Photolysis of PAH Absorbed on Silica Gel and Fly ASh, Phenotyping Cytochromes P-450 with Monoclonal Antibodies, Leaching of PAH from Industrial Wastes with Municipal Waste Leachate, and Determinants of the Potencies of Carcinogenic Mineral Oils.

Cooke, M.; Dennis, A.J.

1986-01-01

44

Dihydrodiol dehydrogenase and polycyclic aromatic hydrocarbon metabolism  

SciTech Connect

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.

Smithgall, T.E.

1986-01-01

45

Detoxification of polycyclic aromatic hydrocarbons by fungi  

Microsoft Academic Search

Summary The polycyclic aromatic hydrocarbons (PAHs) are a group of hazardous environmental pollutants, many of which are acutely toxic, mutagenic, or carcinogenic. A diverse group of fungi, includingAspergillus ochraceus, Cunninghamella elegans, Phanerochaete chrysosporium, Saccharomyces cerevisiae, andSyncephalastrum racemosum, have the ability to oxidize PAHs. The PAHs anthracene, benz[a]anthracene, benzo[a]pyrene, fluoranthene, fluorene, naphthalene, phenanthrene, and pyrene, as well as several methyl-, nitro-,

John B. Sutherland

1992-01-01

46

Arenium acid catalyzed deuteration of aromatic hydrocarbons.  

PubMed

The arenium acid [mesitylene-H](+) has been shown to be an extraordinarily active H/D exchange catalyst for the perdeuteration of polycyclic aromatic hydrocarbons. The reactions take place under ambient conditions in C6D6 as an inexpensive deuterium source. High isolated yields and excellent degrees of deuterium incorporation were achieved using the substrates p-terphenyl, fluoranthene, pyrene, triphenylene, and corannulene. PMID:23163918

Duttwyler, Simon; Butterfield, Anna M; Siegel, Jay S

2013-03-01

47

Polycyclic aromatic hydrocarbon emissions from motorcycles  

Microsoft Academic Search

Emissions of polycyclic aromatic hydrocarbons (PAHs, 2–7 ring) and regulated air pollutants (CO, HC, NOx, 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

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

2005-01-01

48

Polycyclic aromatic hydrocarbons in the diet  

Microsoft Academic Search

Polycyclic aromatic hydrocarbons (PAHs), of which benzo[a]pyrene is the most commonly studied and measured, are formed by the incomplete combustion of organic matter. They are widely distributed in the environment and human exposure to them is unavoidable. A number of them, such as benzo[a]pyrene, are carcinogenic and mutagenic, and they are widely believed to make a substantial contribution to the

David H Phillips

1999-01-01

49

Atmospheric polycyclic aromatic hydrocarbons in Seoul, Korea  

Microsoft Academic Search

Daily particulate- and vapor-phase polycyclic aromatic hydrocarbons (PAH) samples were collected at an urban site in Seoul, Korea, during five intensive sampling campaigns between October 1998 and December 1999. PAH samples collected on quartz fiber filters and PUF plugs were first extracted using dichloromethane with ultrasonication and supercritical fluid extraction methods, respectively, and then analyzed by GC\\/MSD\\/SIM. Seasonal trends in

Seung S. Park; Young J. Kim; Chang H. Kang

2002-01-01

50

Analysis of nitrated polynuclear aromatic hydrocarbons  

Microsoft Academic Search

A derivatization-gas chromatography\\/electron capture detector (GC\\/ECD) method has been developed for the measurement of trace nitrated polynuclear aromatic hydrocarbons (NPAHs) in air. The method involves first the derivatization of parent nitro-PAHs to their corresponding fluorinated derivatives, followed by GC\\/ECD analysis. The sensitivity of the method is an order of magnitude higher than those of direct GC\\/ECD analysis of NPAHs themselves.

Xu Jinhui; Frank S. C Lee

2001-01-01

51

Fungi growing on aromatic hydrocarbons: biotechnology's unexpected encounter with biohazard?  

Microsoft Academic Search

The biodegradation of aromatic hydrocarbons by fungi has traditionally been considered to be of a cometabolic nature. Recently, however, an increasing number of fungi isolated from air biofilters exposed to hydrocarbon-polluted gas streams have been shown to assimilate volatile aromatic hydrocarbons as the sole source of carbon and energy. The biosystematics, ecology, and metabolism of such fungi are reviewed here,

Richard Summerbell; G. Sybren de Hoog

2006-01-01

52

Polycyclic Aromatic Hydrocarbons in Soils and Recent Sediments  

Microsoft Academic Search

Soils and recent marine sediments contain a complex polycyclic aromatic hydrocarbon assemblage. There is a high degree of similarity in the molecular weight distribution of the many series of alkyl homologs of these aromatic hydrocarbons, and this distribution varies little over a wide range of depositional environments. The evidence suggests that these hydrocarbons are formed in natural fires, are dispersed

M. Blumer; W. W. Youngblood

1975-01-01

53

The Uptake of Aromatic and Branched Chain Hydrocarbons by Yeast.  

National Technical Information Service (NTIS)

Studies of the hydrocarbon utilizing yeasts, Candida maltosa and C. lipolytica, have shown that both were capable of reducing recoverable amounts of branched chain and aromatic hydrocarbons in a mixture of naphthalene, tetradecane, hexadecane, pristane (t...

S. A. Crow S. L. Bell D. G. Ahearn

1980-01-01

54

TRACE ANALYSIS FOR AROMATIC HYDROCARBONS IN NATURAL WATERS  

EPA Science Inventory

A method of trace analysis of volatile aromatic hydrocarbons in natural water is described. The method is based on sparging water samples with nitrogen, adsorption of hydrocarbons on activated charcoal, followed by desorption into carbon disulfide and gas chromatographic analysis...

55

THE UPTAKE OF AROMATIC AND BRANCHED CHAIN HYDROCARBONS BY YEAST  

EPA Science Inventory

Studies of the hydrocarbon utilizing yeasts, Candida maltosa and C. lipolytica, have shown that both were capable of reducing recoverable amounts of branched chain and aromatic hydrocarbons in a mixture of naphthalene, tetradecane, hexadecane, pristane (tetra-methylpentadecane). ...

56

QUANTITATIVE ANALYSIS OF POLYNUCLEAR AROMATIC HYDROCARBONS IN LIQUID FUELS  

EPA Science Inventory

Polynuclear aromatic hydrocarbons (PNAs), formed in combustion processes with liquid hydrocarbon fuels, contribute to mobile source exhaust emissions. Because correlation between PNA levels in automobile exhaust and pre-existent PNAs in fuel has been demonstrated in previous work...

57

Potency Equivalency Factors for Some Polycyclic Aromatic Hydrocarbons and Polycyclic Aromatic Hydrocarbon Derivatives  

Microsoft Academic Search

Potency equivalency factors (PEFs) for cancer induction relative to benzo[a]pyrene have been derived for 21 polycyclic aromatic hydrocarbons (PAHs) and PAH derivatives based on a data preference scheme. PEFs have been derived only for PAHs with demonstrated carcinogenicity in bioassays. Cancer potency values and inhalation unit risks are presented for four additional carcinogenic PAHs based on expedited risk assessments conducted

J. F. Collins; J. P. Brown; G. V. Alexeeff; A. G. Salmon

1998-01-01

58

Recent Changes in Atmospheric Polycyclic Aromatic Hydrocarbons (PAHs) and Nitropolycyclic Aromatic Hydrocarbons (NPAHs) in Shenyang, China  

Microsoft Academic Search

Airborne particulates were collected in three size fractions by using Anderson low-volume air samplers in Shenyang, China, in winter and summer in 2007. Compared with data obtained in 2001 at the same sites, the total concentrations of nine polycyclic aromatic hydrocarbons (PAHs) in winter decreased by 67% at one site and decreased by 40% at the other site, while the

Ning Tang; Takahiro Tokuda; Akihiko Izzaki; Kenji Tamura; Ruonan Ji; Xuemei Zhang; Lijun Dong; Takayuki Kameda; Akira Toriba; Kazuichi Hayakawa

2011-01-01

59

Biomarkers of Exposure to Polycyclic Aromatic Hydrocarbons and Related Compounds  

Microsoft Academic Search

Polycyclic aromatic hydrocarbons (PAHs) and nitropolycyclic aromatic hydrocarbons (NPAHs) are widespread carcinogenic compounds that arise from occupational, environmental and dietary sources. The metabolites of PAHs and NPAHs in biological fluids have been investigated as potential biomarkers for assessing human exposure to them, and, particularly, urinary metabolites are the excelle nt candidates due to the non-invasiveness and convenience of collecting the

Akira Toriba; Kazuichi Hayakawa

2007-01-01

60

Mechanisms for polycyclic aromatic hydrocarbon degradation by ligninolytic fungi  

Microsoft Academic Search

Ligninolytic fungi accomplish the partial degradation of numerous aromatic organopollutants. Their ability to degrade polycyclic aromatic hydrocarbons (PAHs) is particularly interesting because eukaryotes were previously considered to be unable to cleave fused-ring aromatics. Recent results indicate that extracellular peroxidases of these fungi are responsible for the initial oxidation of PAHs. Fungal lignin peroxidases oxidize certain PAHs directly, whereas fungal manganese

Kenneth E. Hammel

1995-01-01

61

Considerations of Atmospheric Behaviors of Polycyclic Aromatic Hydrocarbons, Nitropolycyclic Aromatic Hydrocarbons and Inorganic Pollutants Based on Their Interrelationships  

Microsoft Academic Search

Airborne particulates were collected during the same periods in downtown Kanazawa, Sapporo and Tokyo and polycyclic aromatic hydrocarbons (PAHs) and nitropolycyclic aromatic hydrocarbons (NPAHs) were determined together with several heavy metal elements and water-soluble inorganic ions. The mean concentrations of metal elements and inorganic ions were the highest in Tokyo, followed by Sapporo and the lowest in Kanazawa both in

Hitoshi Kakimoto; Hitoshi Yokoe; Yutaka Matsumoto; Shigekatsu Sakai; Fumio Kanoh; Tsuyoshi Murahashi; Kazuhiko Akutsu; Akira Toriba; Ryoichi Kizu; Kazuichi Hayakawad

2001-01-01

62

Coumarin, Naphthalene, and Additional Polycyclic Aromatic Hydrocarbons  

NSDL National Science Digital Library

The featured molecules this month are drawn from two papers. The first, "One-Pot Synthesis of 7-Hydroxy-3-carboxycoumarin in Water", is a Green Chemistry feature by Fringuelli, Piermatti, and Pizzo. The three-dimensional versions of the molecules in the synthesis of the coumarin derivative are directly tied to the reaction scheme included in the paper, opening the possibility of showing large numbers of complex synthetic pathways in this manner.The second paper is "Determining the Carbon-Carbon Distance in an Organic Molecule with a Ruler" by Simoni, Tubino, and Ricchi. This article describes an experiment to determine the size of a naphthalene molecule, using an extension of classic experiments for determining molecular size and Avogadro's number. While the structure of naphthalene will come as no surprise to most students, the molecule collection also includes additional polycyclic aromatic hydrocarbons (PAHs) that can be used to introduce students to the environmental and health issues related to these molecules.

63

Analysis of nitrated polynuclear aromatic hydrocarbons.  

PubMed

A derivatization-gas chromatography/electron capture detector (GC/ECD) method has been developed for the measurement of trace nitrated polynuclear aromatic hydrocarbons (NPAHs) in air. The method involves first the derivatization of parent nitro-PAHs to their corresponding fluorinated derivatives, followed by GC/ECD analysis. The sensitivity of the method is an order of magnitude higher than those of direct GC/ECD analysis of NPAHs themselves. The method is simple and robust and thus ideally suited for the routine monitoring of NPAHs in air samples. The sensitivity and reproducibility of GC/negative ion chemical ionization MS (NICIMS) for the measurement of NPAHs after derivatization has been evaluated. The method has sensitivity comparable to GC/ECD, but is less reproducible in quantification. The method is therefore suitable for method validation and NPAHs peak confirmation rather than routine operations. PMID:11100923

Jinhui, X; Lee, F S

2001-01-01

64

Partially oxidized polycyclic aromatic hydrocarbons show an increased bioavailability and biodegradability  

Microsoft Academic Search

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, for instance, convert polycyclic aromatic hydrocarbons to more water soluble and bioavailable products. Polycyclic aromatic hydrocarbon metabolites were more

Rogier Meulenberg; Huub H. M Rijnaarts; Hans J Doddema; Jim A Field

1997-01-01

65

Degradation of polycyclic aromatic hydrocarbons by manganese peroxidase of Nematoloma frowardii  

Microsoft Academic Search

The degradation of polycyclic aromatic hydrocarbons by a manganese peroxidase crude preparation of Nematoloma frowardii was demonstrated for a mixture of eight different polycyclic aromatic hydrocarbons, and the five individual polycyclic aromatic hydrocarbons phenanthrene, anthracene, pyrene, fluoranthene, and benzo[a]pyrene. Oxidation of polycyclic aromatic hydrocarbons was enhanced by the addition of glutathione, a mediator substance, able to form reactive thiyl radicals.

Ute Sack; Martin Hofrichter; Wolfgang Fritsche

1997-01-01

66

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

Microsoft Academic Search

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 toluene from heptane by extraction with ionic liquids.Several ionic liquids are suitable for extraction of toluene from

G. Wytze Meindersma; André B. de Haan

2005-01-01

67

ORIGINS OF POLYCYCLIC AROMATIC HYDROCARBONS IN ESTUARINE SEDIMENTS  

EPA Science Inventory

In order to determine the origin of polycyclic aromatic hydrocarbons (PAHs) in sediments from Narragansett Bay, Rhode Island, the PAH assemblages from the sediments and from possible origin materials were analyzed by gas chromatographic and gas chromatographic-mass spectrometric ...

68

Infrared Spectroscopy of Matrix-Isolated Polycyclic Aromatic Hydrocarbon Cations.  

National Technical Information Service (NTIS)

Gaseous, ionized polycyclic aromatic hydrocarbons (PAHS) are thought to be responsible for a very common family of interstellar infrared emission bands. Here the near- and mid-infrared spectra of the cations of the five most thermodynamically favored PAHs...

D. M. Hudgins L. J. Allamandola

1995-01-01

69

Infrared Spectroscopy of Matrix-Isolated Polycyclic Aromatic Hydrocarbon Cations.  

National Technical Information Service (NTIS)

Gaseous, ionized polycyclic aromatic hydrocarbons (PAHs) are thought to be responsible for a very common family of interstellar infrared emission bands. Here the near- and mid-infrared spectra of the cations of the five most thermodynamically favored PAHs...

D. M. Hudgins L. J. Allamandola

1995-01-01

70

CONSTRUCTING MICROBIAL STRAINS FOR DEGRADATION OF HALOGENATED AROMATIC HYDROCARBONS  

EPA Science Inventory

The book chapter examines methods that have been used to isolate and to construct bacteria capable of growing aerobically with chlorinated aromatic compounds, including chlorinated hydrocarbons. It also describes some recent work in this area of research....

71

BIODEGRADATION OF POLYCYCLIC AROMATIC HYDROCARBONS BY PHANEROCHAETE CHRYSOSPORIUM  

EPA Science Inventory

The ability of the white rot fungus Phanerochaete chrysosporium to degrade polycyclic aromatic hydrocarbons (PAHS) that are present in anthracene oil (a distillation product obtained from coal tar) was demonstrated. nalysis by capillary gas chromatography and high-performance liq...

72

ENGINEERED ANTIBODIES FOR MONITORING OF POLYNUCLEAR AROMATIC HYDROCARBONS  

EPA Science Inventory

The objective of this multidisciplinary project is to use molecular biological techniques to derive a set of antibodies with useful affinities and selectivities for recovery and detection of polynuclear aromatic hydrocarbons (PAHs) in environmental and biological samples. The lon...

73

Polycyclic Aromatic Hydrocarbons and the Diffuse Interstellar Bands: A Survey.  

National Technical Information Service (NTIS)

We discuss the proposal relating the origin of some of the diffuse interstellar bands (DIBs) to neutral and ionized polycyclic aromatic hydrocarbons (PAHs) present in interstellar clouds. Laboratory spectra of several PAHs, isolated at low temperature in ...

F. Salama G. A. Galazutdinov J. Krelowski L. J. Allamandola F. A. Musaev

1999-01-01

74

Double photoionization of pyrene and other aromatic hydrocarbons  

NASA Astrophysics Data System (ADS)

We have measured the ratio of doubly to singly charged parent ions of pyrene, an aromatic hydrocarbon, for photon energies ranging from threshold to the carbon K edge. Monochromatized synchrotron radiation of the Synchrotron Radiation Center has been used in combination with an ion time-of-flight spectrometer for this investigation. We compared these results with our previous measurements on benzene, coronene and pyrrole. We will discuss differences and similarities in the double photoionization for these aromatic hydrocarbons.

Wehlitz, R.; Hartman, T.

2014-04-01

75

Determination of aromatic hydrocarbons in urban air of Rome  

Microsoft Academic Search

Aromatic hydrocarbons were measured in Rome during 1992–1993 by means a differential optical absorption spectrometer (DOAS) and an automatic gas chromatograph (VOC analyzer). The mean distribution of aromatic hydrocarbons was: benzene 12.6%, toluene 35.4%, and remaining species 42%. The mean yearly concentrations of toluene (128 and 138 ?g m?3) were 2–3 times higher than those of benzene (40 and 47

D. Brocco; R. Fratarcangeli; L. Lepore; M. Petricca; I. Ventrone

1997-01-01

76

Methane direct conversion to aromatic hydrocarbons at low reaction temperature  

Microsoft Academic Search

Conversion of pure methane and natural gas with different methane purity to aromatic hydrocarbons at. 773 and 873 K have been\\u000a investigated. Conversion of methane to aromatics under non-oxidizing conditions can be initiated by higher hydrocarbon mixtures\\u000a in the feed and, some special coke deposited on Mo\\/HZSM-5 catalyst at lower reaction temperature. Methane conversion of about\\u000a 10–20% is obtained at

Liliana B. Pierella; Linsheng Wang; Oscar A. Anunziata

1997-01-01

77

Determinants of polycyclic aromatic hydrocarbon levels in house dust  

PubMed Central

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

WHITEHEAD, TODD; METAYER, CATHERINE; GUNIER, ROBERT B.; WARD, MARY H.; NISHIOKA, MARCIA G.; BUFFLER, PATRICIA; RAPPAPORT, STEPHEN M.

2010-01-01

78

The molecular biology of environmental aromatic hydrocarbons  

SciTech Connect

The induction of mutations in living cells by polycyclic aromatic hydrocarbons (PAH) has been recognized for many years. Although the mechanism for this occurrence has been examined by numerous investigators, the precise nature and type of mutations induced is still unclear. Earlier investigations of DNA damage and repair were primarily examined by the random alkylation of bacterial and mammalian DNAs, in vivo, using a variety of different PAH agents. This procedure is still used today. Though informative, such studies have not offered any explanation of the mechanism by which PAH agents induce carcinogenesis. We have attempted to examine the repair of PAH-damaged DNA using small DNA oligomer constructs as targets for site-specific alkylation. DNA constructs containing a single BPDE alkylated site in each duplex strand were ligated into M13 RF DNA and used to transfect E. coli. Progeny M13 DNA was isolated from E. coli colonies grown on agar plates containing IPTG and Xgal. DNA sequence analysis of the isolated progeny M13 DNA, at the site of construct insertion, was found to contain large deletions and illegitimate recombinants. These sequence rearrangements occurred in either recA{sup +} or recA{sup -} host cells suggesting that SOS processing was not involved in the deletions and the recombinants observed. The mechanism by which BPDE induces illegitimate recombinants has not been resolved, however, it is possible that the closely spaced adducts activate the recombinant machinery in our DNA-damaged cells. 1 ref., 6 figs., 1 tab.

Weiss, S.B.

1989-12-01

79

Porphyrins fused with unactivated polycyclic aromatic hydrocarbons.  

PubMed

A systematic study of the preparation of porphyrins with extended conjugation by meso,?-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 ?,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,?-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 (?(max) = 730 nm), coronenyl (?(max) = 780 nm), pyrenyl (?(max) = 815 nm), and perylenyl (?(max) = 900 nm) annulated porphyrins. Despite being conjugated with unsubstituted fused PAHs, the ?,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 ?(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. PMID:22077105

Diev, Vyacheslav V; Schlenker, Cody W; Hanson, Kenneth; Zhong, Qiwen; Zimmerman, Jeramy D; Forrest, Stephen R; Thompson, Mark E

2012-01-01

80

Emission of polycyclic aromatic hydrocarbons in China  

SciTech Connect

Emission of 16 polycyclic aromatic hydrocarbons (PAHs) listed as U.S. Environmental Protection Agency (U.S. EPA) priority pollutants from major sources in China were compiled. Geographical distribution and temporal change of the PAH emission, as well as emission profiles, are discussed. It was estimated that the total PAH emission in China was 25,300 tons in 2003. The emission profile featured a relatively higher portion of high molecular weight (HMW) species with carcinogenic potential due to large contributions of domestic coal and coking industry. Among various sources, biomass burning, domestic coal combustion, and the coking industry contributed 60%, 20%, and 16% of the total emission, respectively. Total emission, emission density, emission intensity, and emission per capita showed geographical variations. In general, the southeastern provinces were characterized by higher emission density, while those in western and northern China featured higher emission intensity and population-normalized emission. Although energy consumption in China went up continuously during the past two decades, annual emission of PAHs fluctuated depending on the amount of domestic coal consumption, coke production, and the efficiency of energy utilization. 47 refs., 6 figs.

Shanshan Xu; Wenxin Liu; Shu Tao [Peking University, Beijing (China). Laboratory for Earth Surface Processes, College of Environmental Sciences

2006-02-01

81

Polynuclear aromatic hydrocarbons in the water environment*  

PubMed Central

Many polynuclear aromatic hydrocarbons (PAH) are known to be carcinogenic to animals and probably to man. This review is concerned with carcinogenic and non-carcinogenic PAH in the water environment, with emphasis on 3,4-benzpyrene (BP) because it is ubiquitous, is one of the most potent of the carcinogenic PAH and has been widely studied. Although PAH are formed in combustion and other high-temperature processes, there is also evidence for their endogenous formation in plants, which may explain their ubiquity therein. Although the solubility of these compounds in pure water is very low, they may be solubilized by such materials as detergents, or they may otherwise occur in aqueous solution associated with or adsorbed on to a variety of colloidal materials or biota, and thereby be transported through the water environment. A notable characteristic of PAH is their sensitivity to light. PAH have been found in industrial and municipal waste effluents, and occur in soils, ground waters and surface waters, and their sediments and biota. With the exception of filtration or sorption by activated carbon, conventional water treatment processes do not efficiently remove them, and they have been found in domestic water supplies. Because of the ubiquity of PAH in the environment, it is impossible to prevent completely man's exposure to them; nevertheless their surveillance should be continued and their concentrations in the environment should be reduced where practicable.

Andelman, Julian B.; Suess, Michael J.

1970-01-01

82

Strong Correlation Physics in Aromatic Hydrocarbon Superconductors  

NASA Astrophysics Data System (ADS)

We show, by means of ab-initio calculations, that electron-electron correlations play an important role in doped aromatic hydrocarbon superconductors, including potassium doped picene with Tc= 18K [1], coronene and phenanthrene [2]. For the case of picene the inclusion of exchange interactions by means of hybrid functionals reproduces the correct gap for the undoped compound and predicts an antiferromagnetic state for x=3, where superconductivity has been observed [3]. The latter finding is compatible with a sizable value of the correlation strength. The differences between the different compounds are analyzed and results of Dynamical Mean-Field Theory including both correlation effects and electron-phonon interactions are presented. Finally we discuss the consequences of strong correlations in an organic superconductor in relation to the properties of Cs3C60, in which electron correlations drive an antiferromagnetic state [4] but also lead to an enhancement of superconductivity [5]. 1. R. Mitsuhashi et al. Nature 464, 76 (2010)2. X.F. Wang et al, Nat. Comm. 2, 507 (2011)3. G. Giovannetti and M. Capone, Phys. Rev. B 83, 134508 (2011)4. Y. Takabayashi et al., Science 323, 1585 (2009)5. M. Capone et al. Rev. Mod. Phys. 81, 943 (2009

Capone, Massimo; Giovannetti, Gianluca

2012-02-01

83

Polycyclic aromatic hydrocarbons in the bakery chain.  

PubMed

The level of polycyclic aromatic hydrocarbons occurrence and the possibility of their formation in the bakery chain, its raw materials and final products, were examined. Experimental bread baking, with different baking temperatures, was performed in the Warsaw bakery, using cyclothermic deck ovens. PAHs determination was performed by high-pressure liquid chromatography with fluorescent and diode array detectors (HPLC-FLD/DAD) and confirmed by gas chromatography coupled with mass spectrometry (GC/MS). Total content of 19 PAHs in the grain, flour and bran varied from 1.07 to 3.65 ?g/kg and, in bread, from 1.59 to 13.6 ?g/kg depending on the part of bread and baking temperature. Based on the dough's contamination level and the influence of the baking temperature on the bread's PAHs content, it was confirmed that PAHs are formed during baking. Considering the results of the average dietary exposure to PAHs and the MOE (Margin of Exposure) analysis, it could be concluded that analysed bread and cereal products constitute little concern for consumer health. PMID:23768318

Ciecierska, M; Obiedzi?ski, M W

2013-11-01

84

Polycyclic aromatic hydrocarbons and olive pomace oil.  

PubMed

The occurrence of polycyclic aromatic hydrocarbons (PAHs) in five samples of olive pomace oil has been studied to determine the contamination degree of this type of oil and to evaluate if specific purification steps must be introduced during its manufacture. The PAHs present have been determined by gas chromatography-mass spectrometry. A high number of PAHs, with a wide range of molecular weights and in very high concentrations, have been found in four of the samples studied. A very high number of alkyl derivatives and, in many cases, in higher concentrations than their respective parent PAHs, have also been identified. One of the samples, however, presents a more reduced number of PAHs and in significantly lower concentrations than the others. These findings reveal that it is necessary to introduce adequate cleanup steps in the manufacturing process of olive pomace oil, which can give rise to oils with a relatively low content of PAHs. Some carcinogenic PAHs have also been identified, both unalkylated and alkylated. PMID:15053562

Guillén, María D; Sopelana, Patricia; Palencia, Gemma

2004-04-01

85

Mechanisms for polycyclic aromatic hydrocarbon degradation by ligninolytic fungi  

SciTech Connect

Ligninolytic fungi accomplish the partial degradation of numerous aromatic organopollutants. Their ability to degrade polycyclic aromatic hydrocarbons (PAHs) is particularly interesting because eukaryotes were previously considered to be unable to cleave fused-ring aromatics. Recent results indicate that extracellular peroxidases of these fungi are responsible for the initial oxidation of PAHs. Fungal lignin peroxidases oxidize certain PAHs directly, whereas fungal manganese peroxidases co-oxidize them indirectly during enzyme-mediated lipid peroxidation. 14 refs., 3 figs., 1 tab.

Hammel, K.E. [Dept. of Agriculture, Madison, WI (United States)

1995-06-01

86

Comparison of polycyclic aromatic hydrocarbons and nitropolycyclic aromatic hydrocarbons in airborne particulates collected in downtown and suburban Kanazawa, Japan  

Microsoft Academic Search

In this study, airborne particulates were collected at three sites, two in a downtown area and the other in a suburban area of Kanazawa, Japan in each season for 7 years. Two polycyclic aromatic hydrocarbons (PAHs), pyrene (Py) and benzo[a]pyrene (BaP) and four nitropolycyclic aromatic hydrocarbons (NPAHs), 1-nitropyrene (NP) and 1,3-, 1,6-, and 1,8-dinitropyrenes (DNP) were determined by high-performance liquid

Kazuichi Hayakawa; Ning Tang; Kazuhiko Akutsu; Tsuyoshi Murahashi; Hitoshi Kakimoto; Ryoichi Kizu; Akira Toriba

2002-01-01

87

Characteristics of Atmospheric Polycyclic Aromatic Hydrocarbons and Nitropolycyclic Aromatic Hydrocarbons in Hanoi-Vietnam, as a Typical Motorbike City  

Microsoft Academic Search

We investigated polycyclic aromatic hydrocarbons (PAHs) and nitropolycyclic aromatic hydrocarbons (NPAHs) in airborne particulates collected at two sites (I and T) in Hanoi city, a typical city where traffic jams were caused by many motorbikes. The mean total concentration of 10 PAHs having 4–6 rings at sites I and T ranged from 9.6–63.7 pmol m and from 24.8–41.9 pmol m,

PHAM CHAU THUY; TAKAYUKI KAMEDA; AKIRA TORIBA; NING TANG; KAZUICHI HAYAKAWA

2012-01-01

88

Aliphatic and aromatic hydrocarbons in coastal caspian Sea sediments  

Microsoft Academic Search

This investigation represents the first extensive study of the spatial distribution and sources of aliphatic (n-alkanes and unresolved complex mixture of fossil hydrocarbons) and polycyclic aromatic hydrocarbons (PAHs) in coastal sediments from the Caspian Sea. PAH concentrations, n-alkanes and biomarker profiles all suggested that there was limited petrogenic contamination in the shallow North Caspian Sea sediments, which are coarse with

Imma Tolosa; Stephen de Mora; Mohammad Reza Sheikholeslami; Jean-Pierre Villeneuve; Jean Bartocci; Chantal Cattini

2004-01-01

89

Rapid, microwave-assisted perdeuteration of polycyclic aromatic hydrocarbons.  

PubMed

A simple and convenient method for the perdeuteration of polycyclic aromatic hydrocarbons that does not require strong acid has been developed. Using commercially available reagents, the one-step procedure provides a new route to perdeuterated derivatives of both common and exotic polycyclic aromatic hydrocarbons. Microwave irradiation of the hydrocarbons in a solution of dimethylformamide-d7 containing potassium tert-butoxide affords rapid and essentially complete H/D exchange. For example, corannulene is converted to corannulene-d10 with >98% deuterium incorporation in just 1 h of microwave irradiation in a solution of t-BuOK/DMF-d7. PMID:23121393

Greene, Allison K; Scott, Lawrence T

2013-03-01

90

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

National Technical Information Service (NTIS)

Experimental and detailed chemical kinetic modeling has been performed to investigate aromatic and polyaromatic hydrocarbon formation pathways in a rich, sooting, ethylene-oxygen-argon premixed flame. An atmospheric pressure, laminar flat flame operated a...

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

1996-01-01

91

Polycyclic Aromatic Hydrocarbon Far-infrared Spectroscopy  

NASA Astrophysics Data System (ADS)

The far-IR characteristics of astrophysically relevant polycyclic aromatic hydrocarbons (PAHs) averaging in size around 100 carbon atoms have been studied using the theoretical spectra in the NASA Ames PAH IR Spectroscopic Database. These spectra were calculated using density functional theory. Selections of PAH species are made, grouped together by common characteristics or trends, such as size, shape, charge, and composition, and their far-IR spectra compared. The out-of-plane modes involving the entire molecule are explored in detail, astronomical relevance is assessed, and an observing strategy is discussed. It is shown that PAHs produce richer far-IR spectra with increasing size. PAHs also produce richer far-IR spectra with increasing number of irregularities. However, series of irregular-shaped PAHs with the same compact core have common "Jumping-Jack" modes that "pile up" at specific frequencies in their average spectrum. For the PAHs studied here, around 100 carbon atoms in size, this band falls near 50 ?m. PAH charge and nitrogen inclusion affect band intensities but have little effect on far-IR band positions. Detailed analysis of the two-dimensional, out-of-plane bending "drumhead" modes in the coronene and pyrene "families" and the one-dimensional, out-of-plane bending "bar" modes in the acene "family" show that these molecular vibrations can be treated as classical vibrating sheets and bars of graphene, respectively. The analysis also shows that the peak position of these modes is very sensitive to the area of the emitting PAH and does not depend on the particular geometry. Thus, these longest wavelength PAH bands could provide a unique handle on the size of the largest species in the interstellar PAH family. However, these bands are weak. Observing highly excited regions showing the mid-IR bands in which the emission from classical dust peaks at short wavelengths offers the best chance of detecting PAH emission in the far-IR. For these regions sensitivity is not an issue, spectral contrast is maximized and the PAH population is only comprised of highly stable, compact symmetric PAHs, such as the members of the pyrene and coronene "families" discussed in detail here.

Boersma, C.; Bauschlicher, C. W., Jr.; Ricca, A.; Mattioda, A. L.; Peeters, E.; Tielens, A. G. G. M.; Allamandola, L. J.

2011-03-01

92

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

NASA Technical Reports Server (NTRS)

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

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

2001-01-01

93

Fungi growing on aromatic hydrocarbons: biotechnology's unexpected encounter with biohazard?  

PubMed

The biodegradation of aromatic hydrocarbons by fungi has traditionally been considered to be of a cometabolic nature. Recently, however, an increasing number of fungi isolated from air biofilters exposed to hydrocarbon-polluted gas streams have been shown to assimilate volatile aromatic hydrocarbons as the sole source of carbon and energy. The biosystematics, ecology, and metabolism of such fungi are reviewed here, based in part on re-evaluation of a collection of published hydrocarbon-degrading isolates obtained from authors around the world. Incorrect or outdated identifications in original publications are corrected by ribosomal DNA sequence analysis. The data show that many volatile-hydrocarbon-degrading strains are closely related to, or in some cases clearly conspecific with, the very restricted number of human-pathogenic fungal species causing severe mycoses, especially neurological infections, in immunocompetent individuals. Neurochemistry features a distinctive array of phenolic and aliphatic compounds that are related to molecules involved in the metabolism of aromatic hydrocarbons. Hence, there may be physiological connections between hydrocarbon assimilation and certain patterns of mammalian infection. PMID:16438682

Prenafeta-Boldú, Francesc X; Summerbell, Richard; Sybren de Hoog, G

2006-01-01

94

SCREENING POLYNUCLEAR AROMATIC POLLUTANTS IN AMBIENT AND INDOOR AIR BY SYNCHRONOUS LUMINESCENCE  

EPA Science Inventory

Polynuclear aromatic (PNA) pollutants are of concern in indoor and outdoor air monitoring because many PNAs are carcinogenic in laboratory animal biotesting. For comprehensive exposure studies, which usually involve large population distributions and extended assessment periods (...

95

Comparative Molecular Analysis of Genes for Polycyclic Aromatic Hydrocarbon Degradation  

Microsoft Academic Search

\\u000a Aromatic hydrocarbons are found ubiquitously in nature. Their sources vary from biosynthesis de novo by organisms to abiotic reactions on naturally-occurring carbon deposits to chemical synthesis by man. It is generally accepted,\\u000a however, that the bulk of aromatic compounds found in the environment are not of biosynthetic origin but are produced through\\u000a the pyrolysis of organic materials such as the

Gerben J. Zylstra; Eungbin Kim; Anil K. Goyal

96

Micellar Extraction of Polycyclic Aromatic Hydrocarbons from Certified Marine Sediment  

Microsoft Academic Search

In the present study the extraction of polycyclic aromatic hydrocarbons from a certified marine sediment (SRM 1941a) with a micellar medium of polyoxyethylene 10 lauryl ether by micro-wave- and ultrasound-assisted method has been evaluated. The analysis of extracts has been carried out by HPLC with fluorimetric detection and wavelength programming. Hydrocarbons with more than three rings gave average recoveries of

Verónica Pino; Juan H. Ayala; Ana M. Afonso; Venerando González

2001-01-01

97

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

SciTech Connect

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

Castaldi, M.J.; Marinov, N.M.; Melius, C.F. [and others

1996-02-01

98

Effects of co-occurring aromatic hydrocarbons on degradation of individual polycyclic aromatic hydrocarbons in marine sediment slurries  

Microsoft Academic Search

Rates of polycyclic aromatic hydrocarbon (PAH) degradation and mineralization were influenced by preexposure to alternate PAHs and a monoaromatic hydrocarbon at relatively high (100 ppm) concentrations in organic-rich aerobic marine sediments. Prior exposure to three PAHs and benzene resulted in enhanced (¹⁴C)naphthalene mineralization, while (¹⁴C)anthracene mineralization was stimulated only by benzene and anthracene preexposure. Preexposure of sediment slurries to phenanthrene

J. E. Bauer; D. G. Capone

1988-01-01

99

EVALUATION OF SENSITIZED FLUORESCENCE FOR POLYNUCLEAR AROMATIC HYDROCARBON DETECTION  

EPA Science Inventory

The report gives results of an evaluation of a fluorescent spot test for detecting the presence of polynuclear aromatic hydrocarbons (PAHs) as a screening technique for samples to be analyzed by Gas Chromatography/Mass Spectrometry (GC/MS). The test is based on the phenomenon of ...

100

METHODOLOGY OF AMBIENT AIR MONITORING FOR POLYCYCLIC AROMATIC HYDROCARBONS  

EPA Science Inventory

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

101

AGRONOMIC OPTIMIZATION FOR PHYTOREMEDIATION OF POLYCYCLIC AROMATIC HYDROCARBONS  

EPA Science Inventory

Phytoremediation is a low-cost method of using plants to degrade, volatilize or sequester organic and metal pollutants that has been used in efforts to remediate sites contaminated with polycyclic aromatic hydrocarbon (PAH) refinery wastes. Non-native plant species aggressivel...

102

Polycyclic Aromatic Hydrocarbons in Maternal and Cord Blood Plasma  

Microsoft Academic Search

Polycyclic aromatic hydrocarbons (PAH) come from incomplete combustion of organic materials, including tobacco smoke. Some PAH are known to be mutagenic and carcinogenic and of concern for the fetus when women smoke during pregnancy. Known consequences of smoking during pregnancy include low birth weight (LBW) and preterm (PT) delivery. This study was designed to measure concentrations of 3 PAH: anthracene

Paula G. Radmacher; Stephen W. Looney; Steven R. Myers

2010-01-01

103

THE RATES OF POLYCYCLIC AROMATIC HYDROCARBON EMISSIONS FROM INCENSE BURNING  

EPA Science Inventory

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

104

Microbial Degradation of Polycyclic Aromatic Hydrocarbons and Characterization of Bacteria  

NASA Astrophysics Data System (ADS)

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.

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

2010-01-01

105

Polycyclic Aromatic Hydrocarbon Degrading Microorganisms in Great Lakes Sediments  

Microsoft Academic Search

Biodegradation is a chemical transformation process that may result in the decontamination of sediments. A criterion for the potential success of biode gradation is the ability of indigenous microorganisms to catabolize contaminants, such as polycyclic aromatic hydrocarbons (PAHs). The number of microorganisms displaying this ability may be influenced by the extent of their exposure to PAHs. In this study, microorganisms

Dan L. McNally; James R. Mihelcic; Donald R. Lueking

1998-01-01

106

Phase distribution of polynuclear aromatic hydrocarbons in ambient air  

Microsoft Academic Search

The determination of concentrations of polynuclear aromatic hydrocarbons (PAH) in ambient air is of considerable importance to characterization of air quality. While these compounds are often found to be associated with airborne particulate matter, many PAH have sufficiently high vapor pressures that appreciable fractions of their total concentrations occur in the vapor phase. This is especially true when sampling is

R. G. Lewis; R. W. Coutant; P. J. Callahan; J. C. Chuang

1988-01-01

107

Hydrogen Coverage of Interstellar PAHs (Polycyclic Aromatic Hydrocarbons).  

National Technical Information Service (NTIS)

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 d...

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

1986-01-01

108

Abiotic synthesis of polycyclic aromatic hydrocarbons on Mars  

Microsoft Academic Search

Thermochemical calculations of metastable equilibria are used to evaluate the stability of condensed polycyclic aromatic hydrocarbons (PAHs) in cooling thermal gases and hydrothermal fluids on ancient Mars, which are roughly similar to their terrestrial counterparts. The effects of temperature, pressure, the extent of PAH alkylation, and the relative stability of PAHs and alkanes are considered. Inhibition of methane and graphite

Mikhail Zolotov; Everett Shock

1999-01-01

109

Biodegradation of Aliphatic vs. Aromatic Hydrocarbons in Fertilized Arctic Soils  

Microsoft Academic Search

The objectives of this study were to (1) test a simple bioremediation treatment strategy in the Arctic and (2) examine the effect of fertilization on the degradation of aliphatic and aromatic hydrocarbons. The site is a coarse sand pad that once supported fuel storage tanks. Concentrations of diesel-range organics at the beginning of the study (July 1996) ranged from 250

Joan F. Braddock; James L. Walworth; Kathleen A. McCarthy

1999-01-01

110

Oxidation of polynuclear aromatic hydrocarbons in water. 1: Ozonation  

Microsoft Academic Search

The oxidation of three polynuclear aromatic hydrocarbons (PAHs), fluorene, phenanthrene, and acenaphthene, in aqueous solution with ozone has been studied. The influence of hydroxyl radical inhibitors, pH, ozone partial pressure, and temperature was investigated. All the PAHs studied show high oxidation rates with ozone. The ozonation of fluorene seems to be due to both direct and hydroxyl radical reactions while

Fernando J. Beltran; J. M. Encinar; J. Rivas; G. Ovejero

1995-01-01

111

Polycyclic aromatic hydrocarbons in Estonian soil: contamination and profiles  

Microsoft Academic Search

The distribution and accumulation of polycyclic aromatic hydrocarbons (PAH) in soil as well as PAH profiles have been investigated in areas with different anthropogenic pollution such as the city of Tallinn, the towns of Pärnu and Kohtla-Järve and some rural areas. PAH were identified in 147 soil samples (0–10 cm upper layer) collected in September 1996. The typical ? PAH

M Trapido

1999-01-01

112

Woodburning as a source of atmospheric polycyclic aromatic hydrocarbons  

Microsoft Academic Search

Airborne particulate matter containing polycyclic aromatic hydrocarbons derived from burning natural vegetation and paper products in a variety of ways was collected and analyzed by HPLC. Similar profiles of compounds resulted from most of the combustion sources that do not involve fossil fuels and that are likely to contribute to Sydney's atmospheric particulates. In addition, the profiles did not change

Diana J. Freeman; Frank C. R. Cattell

1990-01-01

113

Structure-biodegradability relationships of polycyclic aromatic hydrocarbons in soil  

Microsoft Academic Search

The potential of some polycyclic aromatic hydrocarbons (PAH) to be metabolized to mutagenic and\\/or carcinogenic compounds (Cerniglia 1984, Gibson & Subramanian 1984) has caused concern for environmental pollution by this class of residues. In industrialized countries, pollution by PAH is primarily associated with the processing, combustion and disposal of fossil fuels (Bartha & Bossert 1984, Hites& LaFlamme 1977), but low

Ingeborg D. Bossert; Richard Bartha

1986-01-01

114

Emission factors for polycyclic aromatic hydrocarbons from biomass burning  

Microsoft Academic Search

Emission factors for 19 polycyclic aromatic hydrocarbons were measured during wind tunnel simulations of open burning for agricultural and forest biomass fuels including cereal grasses, agricultural tree prunings, and fir and pine wood (slash). Yields of total PAH varied from 5 to 683 mg kg⁻¹ depending principally on burning conditions and to a lesser extent on fuel type. Barley straw

Bryan M. Jenkins; A. Daniel Jones; Scott Q. Turn; Robert B. Williams

1996-01-01

115

Consensus sediment quality guidelines for polycyclic aromatic hydrocarbon mixtures  

Microsoft Academic Search

Sediment quality guidelines (SQGs) for polycyclic aromatic hydrocarbons (PAHs) have been derived from a variety of laboratory, field, and theoretical foundations. They include the screening level concentration, effects ranges-low and -median, equilibrium partitioning concentrations, apparent effects threshold, ΣPAH model, and threshold and probable effects levels. The resolution of controversial differences among the PAH SQGs lies in an understanding of the

Richard C. Swartz

1999-01-01

116

Sources of polycyclic aromatic hydrocarbons to the Hudson River Airshed  

Microsoft Academic Search

Sources of polycyclic aromatic hydrocarbons (PAHs) to the Hudson River Estuary Airshed were investigated using positive matrix factorization (PMF). A three-city dataset was used to obtain common factor profiles. The contributions of each factor on each sampling day and site were then determined, and a sensitivity analysis was conducted. A stable eight-factor solution was identified. PMF was able to identify

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

2004-01-01

117

Pressurised liquid extraction of polycyclic aromatic hydrocarbons from contaminated soils  

Microsoft Academic Search

The reliability and efficiency of the pressurised liquid extraction technique (PLE) for extracting polycyclic aromatic hydrocarbons (PAHs) from contaminated soil has been investigated. Experimental design was used to study the influence of seven extraction variables (sample load, solvents used, solvent ratios, pressure, temperature, extraction time, and rinse volume). The results show that large sample loads in combination with small solvent

Staffan Lundstedt; Bert van Bavel; Peter Haglund; Mats Tysklind; Lars Öberg

2000-01-01

118

Enhanced Bioremediation of Polycyclic Aromatic Hydrocarbons by Environmentally Friendly Techniques  

Microsoft Academic Search

Polycyclic aromatic hydrocarbons (PAHs) are recognized as a worldwide environmental contamination problem because of their intrinsic chemical stability, high resistance to various transformation processes, and toxicity property. Because of the wide distribution of the PAHs in the environment, human exposure to the PAHs is likely to occur from dermal contact, ingestion of particles, inhalation of airborne dust, or bioaccumulation in

Huey-Min Hwang; Xiaoke Hu; Xueheng Zhao

2007-01-01

119

Distribution of polycyclic aromatic hydrocarbons in lime spray dryer ash  

Microsoft Academic Search

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

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

2005-01-01

120

Dermal Exposure to Polycyclic Aromatic Hydrocarbons among Road Pavers  

Microsoft Academic Search

Objectives: Dermal exposure to polycyclic aromatic hydrocarbons (PAHs) and the role of an industrial by-product, coal fly ash, on workers' PAH exposure were investigated during stone mastic asphalt (SMA) paving and remixing. Methods: PAH exposure was measured at eight sites during the laying of SMA containing coal fly ash or limestone (conventional SMA) as the filler. Six of the surveys

VIRPI VAANANEN; MERVI HAMEILA; PENTTI KALLIOKOSKI; ELINA NYKYRI; PIRJO HEIKKILA

2005-01-01

121

Development of a Fluorescence Polarization Immunoassay for Polycyclic Aromatic Hydrocarbons  

Microsoft Academic Search

A fluorescence polarization immunoassay for detection of polycyclic aromatic hydrocarbons (PAHs) was developed. Fluorescein?labeled tracers based on different PAHs were synthesized and studied in order to achieve a high sensitivity using both monoclonal and polyclonal antibodies. The application of different combinations of antibody tracer pairs allows to separately determine groups of small and large PAHs or to realize a class?specific

Irina Yu Goryacheva; Sergei A. Eremin; Ekaterina A. Shutaleva; Miloslav Suchanek; Reinhard Niessner; Dietmar Knopp

2007-01-01

122

Biodegradation of aromatic hydrocarbons by aquifer microorganisms under denitrifying conditions  

Microsoft Academic Search

A series of laboratory tests were conducted to evaluate whether denitrification would be a suitable alternative for biorestoration of an aquifer contaminated with JP-4 jet fuel. Microcosms were prepared from both uncontaminated and contaminated aquifer material from the site, in an anaerobic glovebox, amended with nitrate, nutrients, and aromatic hydrocarbons, and incubated under a nitrogen atmosphere at 12C. With uncontaminated

Stephen R. Hutchins; Guy W. Sewell; David A. Kovacs

1991-01-01

123

Analysis of polycyclic aromatic hydrocarbons in cooking oil fumes  

Microsoft Academic Search

Various samples of cooking oil fumes were analyzed to an effort to study the relationship between the high incidence of pulmonary adenocarcinoma in Chinese women and cooking oil fumes in the kitchen. Polycyclic aromatic hydrocarbons (PAHs) in samples of cooking oil fumes were extracted, chromatographed, and measured by fluorescence spectrophotometer. The samples included oil fumes from three commercial cooking oils

Li Shuguang; Pan Dinhua; Wang Guoxiong

2009-01-01

124

Analysis of Polycyclic Aromatic Hydrocarbons in Cooking Oil Fumes  

Microsoft Academic Search

Various samples of cooking oil fumes were analyzed to an effort to study the relationship between the high incidence of pulmonary adenocarcinoma in Chinese women and cooking oil fumes in the kitchen. Polycyclic aromatic hydrocarbons (PAHs) in samples of cooking oil fumes were extracted, chromatographed, and measured by fluorescence spectrophotometer. The samples included oil fumes from three commercial cooking oils

Li Shuguang; Pan Dinhua; Wang Guoxiong

1994-01-01

125

Biomonitoring of polycyclic aromatic hydrocarbons in human urine  

Microsoft Academic Search

Measurement of polycyclic aromatic hydrocarbons (PAH) metabolites in human urine is the method of choice to determine occupational and\\/or environmental exposure of an individual to PAH, in particular, when multiple routes of exposure have to be taken into account. Requirements for methods of biomonitoring PAH metabolites in urine are presented. Studies using 1-hydroxypyrene or phenanthrene metabolites including its phenols and

Jürgen Jacob; Albrecht Seidel

2002-01-01

126

Aromatic and polycyclic aromatic hydrocarbon formation in a laminar premixed n-butane flame  

SciTech Connect

Experimental and detailed chemical kinetic modeling work has been performed to investigate aromatic and polycyclic aromatic hydrocarbon (PAH) formation pathways in a premixed, rich, sooting, n-butane-oxygen-argon burner stabilized flame. An atmospheric pressure, laminar flat flame operated at an equivalence ratio of 2.6 was used to acquire experimental data for model validation. Gas composition analysis was conducted by an on-line gas chromatograph/mass spectrometer technique. Measurements were made in the main reaction and post-reaction zones for a number of low molecular weight species, aliphatics, aromatics, and polycyclic aromatic hydrocarbons (PAHs) ranging from two to five-fused aromatic rings. Reaction flux and sensitivity analysis were used to help identify the important reaction sequences leading to aromatic and PAH growth and destruction in the n-butane flame. Reaction flux analysis showed the propargyl recombination reaction was the dominant pathway to benzene formation. The consumption of propargyl by H atoms was shown to limit propargyl, benzene, and naphthalene formation in flames as exhibited by the large negative sensitivity coefficients. Naphthalene and phenanthrene production was shown to be plausibly formed through reactions involving resonantly stabilized cyclopentadienyl and indenyl radicals. Many of the low molecular weight aliphatics, combustion by-products, aromatics, branched aromatics, and PAHs were fairly well simulated by the model. Additional work is required to understand the formation mechanisms of phenyl acetylene, pyrene, and fluoranthene in the n-butane flame. 73 refs.

Marinov, N.M.; Pitz, W.J.; Westbrook, C.K. [Lawrence Livermore National Lab., CA (United States)] [Lawrence Livermore National Lab., CA (United States); Vincitore, A.M.; Castaldi, M.J.; Senkan, S.M. [Univ. of California, Los Angeles, CA (United States)] [Univ. of California, Los Angeles, CA (United States); Melius, C.F. [Sandia National Labs., Livermore, CA (United States)] [Sandia National Labs., Livermore, CA (United States)

1998-07-01

127

Analogs of solid nanoparticles as precursors of aromatic hydrocarbons  

NASA Astrophysics Data System (ADS)

Context. Aromatic =CH and C=C vibrational bands have been observed within shocked interstellar regions, indicating the presence of aromatic emission carriers such as PAHs, which may have been created from adjacent molecular cloud material by interaction with a shock front. Aims: We investigate the evolution of the aromatic =CH and C=C vibrational modes at 3.3 and 6.2 ?m wavelength in heated HAC materials, PAHs and mixed PAHs and HACs, respectively, aiming at an explanation of the evolution of carbonaceous dust grains in the shocked regions. Methods: Materials used in these analogs (HAC and PAH materials) were prepared by the laser ablation and the laser pyrolysis methods, respectively. The transmission electron microscopy (TEM) in high-resolution mode was used as an analytical technique to characterize the aromatic layers in HACs. Spectroscopic analysis was prformed in the mid-IR range. Results: A remarkable destruction of aliphatic structures in HACs has been observed with the thermal processing, while aromatic structures become dominating by increasing the diameters of the graphene layers. The aromatic bands at 3.3 and 6.2 ?m, observed in the laboratory spectra of PAHs and of the combination of the PAHs and HAC materials, are also clearly observed in the spectrum of the heated HACs. These bands agree with those of aromatic bands observed in astronomical observations. Conclusions: Aromatization of HACs could be a pre-stage in the decomposition process of hydrocarbons that form PAH-clusters in such hot interstellar medium.

Gadallah, K. A. K.; Mutschke, H.; Jäger, C.

2013-06-01

128

Effect of fluorine substitution on the aromaticity of polycyclic hydrocarbons.  

PubMed

The effect of fluorine substitution on the aromaticity of polycyclic hydrocarbons (PAH) is investigated. Magnetically induced current densities, current pathways, and current strengths, which can be used to assess molecular aromaticity, are calculated using the gauge-including magnetically induced current method (GIMIC). The degree of aromaticity of the individual rings is compared to those obtained using calculated nucleus-independent chemical shifts at the ring centers (NICS(0) and NICS(0)(zz)). Calculations of explicitly integrated current strengths for selected bonds show that the aromatic character of the investigated polycyclic hydrocarbons is weakened upon fluorination. In contrast, the NICS(0) values for the fluorinated benzenes increase noteworthy upon fluorination, predicting a strong strengthening of the aromatic character of the arene rings. The integrated current strengths also yield explicit current pathways for the studied molecules. The current pathways of the investigated linear polyacenes, pyrene, anthanthrene, coronene, ovalene, and phenanthro-ovalene are not significantly affected by fluorination. NISC(0) and NICS(0)(zz) calculations provide contradictory degrees of aromaticity of the fused individual ring. Obtained NICS values do not correlate with the current strengths circling around the individual rings. PMID:22994485

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

2012-10-18

129

Vibrational Spectra of Polycyclic Aromatic Hydrocarbons Under Pressure  

NASA Astrophysics Data System (ADS)

Polycyclic aromatic hydrocarbons are present in primitive meteorites, and hence their behavior under high-pressure conditions is relevant to carbon processing during planetary formation and accretion. Infrared and Raman spectra have been collected of the polycyclic aromatic hydrocarbons anthracene and pyrene under pressure, with the motivation being to understand how these two materials respond to compression, and ultimately how they form hydrogenated, dense, likely-amorphous carbon-rich materials at high pressures. Thus, our experiments are oriented towards providing data on the bonding within these materials to constrain their 300 K response to compression, and to provide a basis for comparison with shock data. Our infrared data on pyrene (which has four aromatic rings) under pressure show that most spectral features of low-pressure pyrene disappear above 18.0 GPa. The C-H bonding in this material becomes markedly disordered above ~2.0 GPa in the IR and ~3.0 GPa in the Raman. Most spectral features of low-pressure pyrene disappear above 10 GPa in the Raman spectra, in accord with previous studies. Our Raman data on anthracene (which has three aromatic rings) under pressure show that most spectral features disappear above 8.0 GPa and that the C-H bonding becomes markedly disordered above 6.0 GPa. Following decompression of anthracene from 10 GPa, most spectral features returned, including the C-H bands, which suggests that this material does not undergo an irreversible transformation up to this pressure. Comparison with prior work on benzene indicates that the onset of a high-density disordered material in aromatic hydrocarbons hinges on the number of rings present: fewer rings result in markedly greater stability on simple compression. This trend is likely associated with lower pressure onsets of strong intramolecular interactions in progressively larger aromatic hydrocarbons.

O'Bannon, E. F.; Williams, Q.

2013-12-01

130

Aromatic and Polycyclic Aromatic Hydrocarbon Formation in a Laminar Premixed n-Butane Flame  

Microsoft Academic Search

Experimental and detailed chemical kinetic modeling work has been performed to investigate aromatic and polycyclic aromatic hydrocarbon (PAH) formation pathways in a premixed, rich, sooting, n-butane–oxygen–argon burner stabilized flame. An atmospheric pressure, laminar flat flame operated at an equivalence ratio of 2.6 was used to acquire experimental data for model validation. Gas composition analysis was conducted by an on-line gas

Nick M Marinov; William J Pitz; Charles K Westbrook; Antonio M Vincitore; Marco J Castaldi; Selim M Senkan; Carl F Melius

1998-01-01

131

Growth of fungi on volatile aromatic hydrocarbons  

Microsoft Academic Search

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 environmental polluted soil and groundwater samples in solid state-like batches, air biofilters, and liquid

F. X. Prenafeta Boldú

2002-01-01

132

INDOOR AIR ASSESSMENT - INDOOR CONCENTRATIONS OF ENVIRONMENTAL CARCINOGENS  

EPA Science Inventory

In this report, indoor concentration data are presented for the following general categories of air pollutants: adon-222, environmental tobacco smoke (ETS), asbestos, gas phase organic compounds, formaldehyde, polycyclic aromatic hydrocarbons (PAN), pesticides, and inorganic comp...

133

Accumulation and release of petroleum-derived aromatic hydrocarbons by four species of marine animals  

Microsoft Academic Search

When exposed to oil-contaminated seawater, marine animals accumulate a wide variety of petroleum hydrocarbons in their tissues. Generally, the aromatic hydrocarbons are accumulated to a greater extent and are retained longer than the alkanes. In all species tested, accumulation of aromatic hydrocarbons appears to be dependent primarily on a partitioning of the hydrocarbons between the exposure water and the tissue

J. M. Neff; B. A. Cox; D. Dixit; J. W. Anderson

1976-01-01

134

Biodegradation of Aromatic Hydrocarbons in an Extremely Acidic Environment  

PubMed Central

The potential for biodegradation of aromatic hydrocarbons was evaluated in soil samples recovered along gradients of both contaminant levels and pH values existing downstream of a long-term coal pile storage basin. pH values for areas greatly impacted by runoff from the storage basin were 2.0. Even at such a reduced pH, the indigenous microbial community was metabolically active, showing the ability to oxidize more than 40% of the parent hydrocarbons, naphthalene and toluene, to carbon dioxide and water. Treatment of the soil samples with cycloheximide inhibited mineralization of the aromatic substrates. DNA hybridization analysis indicated that whole-community nucleic acids recovered from these samples did not hybridize with genes, such as nahA, nahG, nahH, todC1C2, and tomA, that encode common enzymes from neutrophilic bacteria. Since these data suggested that the degradation of aromatic compounds may involve a microbial consortium instead of individual acidophilic bacteria, experiments using microorganisms isolated from these samples were initiated. While no defined mixed cultures were able to evolve 14CO2 from labeled substrates in these mineralization experiments, an undefined mixed culture including a fungus, a yeast, and several bacteria successfully metabolized approximately 27% of supplied naphthalene after 1 week. This study shows that biodegradation of aromatic hydrocarbons can occur in environments with extremely low pH values.

Stapleton, Raymond D.; Savage, Dwayne C.; Sayler, Gary S.; Stacey, Gary

1998-01-01

135

Phototransformation of polycyclic aromatic hydrocarbons into stable, mutagenic components  

SciTech Connect

This report compares the mutagenicity of photochemical products produced by exposure of the polycyclic aromatic hydrocarbons benzo(a)pyrene and 9,10-dimethylanthracene or the aromatic amines 2-aminofluorene, 2-aminoanthracene and 2-aminonaphthalene to sunlight or to ultraviolet light (UVA). 2-Aminofluorene, giving the most active products, was further investigated with respect to the mechanism of photoactivation and the chemical identity of the photochemical products. Screening of HPLC resolved photochemical products demonstrated that the majority of the mutagenicity was localized to one peak - which co-chromatographed with 2-nitrofluorene.

Okinaka, R.T.; Nickols, J.W.; Whaley, T.W.; Strniste, G.F.

1983-01-01

136

Modeling of Aromatic and Polycyclic Aromatic Hydrocarbon Formation in Premixed Methane and Ethane Flames  

Microsoft Academic Search

Detailed chemical kinetic modeling has been performed to investigate aromatic and polyaromatic hydrocarbon formation pathways in rich, sooting, methane and ethane premixed flames. An atmospheric pressure, laminar flat flame operated at an equivalence ratio of 2.5 was used to acquire experimental data for model validation. Gas composition analysis was conducted by an on-line gas chromatograph \\/ mass spectrometer technique. Measurements

N. M. Marinov; W. J. Pitz; C. K. Westbrook; M. J. Castaldi; S. M. Senkan

1996-01-01

137

POLYCYCLIC AROMATIC HYDROCARBONS AND AROMATIC PLASTICISER MATERIALS IN THE SEAWATER OF ALEXANDRIA COASTAL AREA  

Microsoft Academic Search

Polycyclic aromatic hydrocarbons (PAHs), the real contaminants of petroleum, were detected in the surface seawater of Alexandria coastal area in winter and spring seasons of 1995. Their order of predominance, particularly for the individual components were principally due to the processes of input, transport and fluxes. Variation of PAHs was not following seasonal changes but it was slightly affected by

MOHAMED KAMAL Z. EL-DEEB; HOSNY I. EMARA

138

Preferential utilization of petroleum oil hydrocarbon components by microbial consortia reflects degradation pattern in aliphatic–aromatic hydrocarbon binary mixtures  

Microsoft Academic Search

In this study, the abilities of two microbial consortia (Y and F) to degrade aliphatic–aromatic hydrocarbon mixtures were\\u000a investigated. Y consortium preferentially degraded the aromatic hydrocarbon fractions in kerosene, while F consortium preferentially\\u000a degraded the aliphatic hydrocarbon fractions. Degradation experiments were performed under aerobic conditions in sealed bottles\\u000a containing liquid medium and n-octane or n-decane as representative aliphatic hydrocarbons or

Hernando Pactao Bacosa; Koichi Suto; Chihiro Inoue

2011-01-01

139

Direct photolysis of polycyclic aromatic hydrocarbons in drinking water sources.  

PubMed

The widely used low pressure lamps were tested in terms of their efficiency to degrade polycyclic aromatic hydrocarbons listed as priority pollutants by the European Water Framework Directive and the U.S. Environmental Protection Agency, in water matrices with very different compositions (laboratory grade water, groundwater, and surface water). Using a UV fluence of 1500 mJ/cm(2), anthracene and benzo(a)pyrene were efficiently degraded, with much higher percent removals obtained when present in groundwater (83-93%) compared to surface water (36-48%). The removal percentages obtained for fluoranthene were lower and ranged from 13 to 54% in the different water matrices tested. Several parameters that influence the direct photolysis of polycyclic aromatic hydrocarbons were determined and their photolysis by-products were identified by mass spectrometry. The formation of photolysis by-products was found to be highly dependent on the source waters tested. PMID:21784577

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

2011-09-15

140

Oxidation of polycyclic aromatic hydrocarbons under sulfate-reducing conditions  

USGS Publications Warehouse

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

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

1996-01-01

141

Polycyclic aromatic hydrocarbons in sediments of the Venice Lagoon  

Microsoft Academic Search

Three sediment cores were collected in the Venice Lagoon: two from mud flats (E, F) and one from the San Giuliano Canal (I1), which borders the industrial district. Samples were analysed for the 15 polycyclic aromatic hydrocarbons (PAHs) listed as priority pollutants by the U.S. EPA. Sediment chronologies were established using both 137Cs and 210Pb activity-depth profiles, and confirmed by

M. Frignani; L. G. Bellucci; M. Favotto; S. Albertazzi

2003-01-01

142

Bioaccumulation and biomagnification of polycyclic aromatic hydrocarbons in aquatic organisms  

Microsoft Academic Search

Uptake and degradation of polycyclic aromatic hydrocarbons were studied in a laboratory scale food chain consisting of Dunaliella tertiolecta (microalga), Mytilus galloprovincialis (mussel) and Dicentrarchus labrax (fish), in tanks supplied with open water flow. The toxicants, benzo(a)pyrene and 7,12-dimethyl benz(a)anthracene, were added and samples were taken every ten days. Bioaccumulation of toxicants in the food chain steps and the physiological

R. D'Adamo; S. Pelosi; P. Trotta; G. Sansone

1997-01-01

143

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

Microsoft Academic Search

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 (mean=394.2±580.7 ng g dry weight (d.w.)) was evident throughout the region. In addition, localised areas of high PAH

Wentao Jiao; Yonglong Lu; Tieyu Wang; Jing Li; Jingyi Han; Guang Wang; Wenyou Hu

2009-01-01

144

Direct arylation of polycyclic aromatic hydrocarbons through palladium catalysis.  

PubMed

We have discovered that the combination of Pd(OAc)(2)/o-chloranil can catalyze the direct C-H bond arylation of polycyclic aromatic hydrocarbons (PAHs) with arylboroxins that occurs selectively at the K-region. The sequential integration of Pd-catalyzed direct arylation of PAHs and FeCl(3)-mediated cyclodehydrogenation is effective in rapidly extending a parent PAH ?-system with high directionality. PMID:21699210

Mochida, Kenji; Kawasumi, Katsuaki; Segawa, Yasutomo; Itami, Kenichiro

2011-07-20

145

Origins of polycyclic aromatic hydrocarbons in estuarine sediments  

Microsoft Academic Search

In order to determine the origin of polycyclic aromatic hydrocarbons (PAHs) in sediments from Narragansett Bay, Rhode Island, the PAH assemblages from the sediments and from possible origin materials were analyzed by gas Chromatographic and gas chromatographic-mass spectrometric techniques. Analyses included determinations of: 1. (1) the relative content of non-alkylated PAH parent molecules i.e. parent compound distributions (PCDs); 2. (2)

James L. Lake; Curtis Norwood; Crandall Dimock; Robert Bowen

1979-01-01

146

Biodegradation of polycyclic aromatic hydrocarbons by a mixed culture  

Microsoft Academic Search

We investigated the potential biodegradation of polycyclic aromatic hydrocarbons (PAHs) by an aerobic mixed culture utilizing phenanthrene as its carbon source. Following a 3–5 h post-treatment lag phase, complete degradation of 5 mg\\/l phenanthrene occurred within 28 h (optimal conditions determined as 30°C and pH 7.0). Phenanthrene degradation was enhanced by the individual addition of yeast extract, acetate, glucose or

S. Y Yuan; S. H Wei; B. V Chang

2000-01-01

147

Electron energy loss spectra of polycyclic aromatic hydrocarbons  

NASA Technical Reports Server (NTRS)

A survey of the electron energy-loss spectroscopy is reported of gas-phase polycyclic aromatic hydrocarbon (PAH) molecules consisting of up to seven rings where the study is limited to the more thermodynamically stable pericondensed systems. The aim of this work is to obtain absorption profiles (proportional to the oscillator strengths) from the visible to the soft X-ray region near 30 eV.

Keller, John W.; Coplan, M. A.; Goruganthu, R.

1992-01-01

148

Polycyclic aromatic hydrocarbons in U. K. Urban air  

Microsoft Academic Search

Polycyclic aromatic hydrocarbon (PAH) data for the first two years (January 1991-December 1992) of a national urban air monitoring scheme in the U.K. are presented. Urban sample sites were operated in the cities of London, Manchester, and Cardiff and in the light industrial town of Stevenage. Both the particulate and vapor phases of 15 PAHs were sampled using high-volume air

Crispin J. Halsall; V. Burnett; K. S. Waterhouse; K. C. Jones; P. J. Coleman; B. J. Davis; P. Harding-Jones

1994-01-01

149

Vegetation-atmosphere partitioning of polycyclic aromatic hydrocarbons  

Microsoft Academic Search

The partitioning of polycyclic aromatic hydrocarbons (PAH) between vegetation and the atmosphere was studied throughout the growing season and under natural conditions. A vegetation-atmosphere partition coefficient (K[sub v]) was derived by analogy to partition coefficients for gas-particle partitioning and fish-water partitioning. K[sub v] is temperature dependent, and from this functional relationship we calculated PAH-vegetation binding energies. These energies were highly

Staci L. Simonich; Ronald A. Hites

1994-01-01

150

Oxidation of Polycyclic Aromatic Hydrocarbons under Sulfate-Reducing Conditions  

PubMed Central

[(sup14)C]naphthalene and phenanthrene were oxidized to (sup14)CO(inf2) without a detectable lag under strict anaerobic conditions in sediments from San Diego Bay, San Diego, Calif., that were heavily contaminated with polycyclic aromatic hydrocarbons (PAHs) but not in less contaminated sediments. Sulfate reduction was necessary for PAH oxidation. These results suggest that the self-purification capacity of PAH-contaminated sulfate-reducing environments may be greater than previously recognized.

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

1996-01-01

151

Photolysis of polycyclic aromatic hydrocarbons adsorbed on simulated atmospheric particulates  

Microsoft Academic Search

Fifteen polycyclic aromatic hydrocarbons (PAH) adsorbed on silica gel, alumina, fly ash, and carbon black were photolyzed in order to study their atmospheric fate. Photolytic half-lives for these particle-bound PAH were found to be highly dependent on the substrate to which they were adsorbed. On silica gel and alumina, PAH showed a wide range of photolytic half-lives, indicating a relationship

Thomas D. Behymer; Ronald A. Hites

1985-01-01

152

Role of radical cations in aromatic hydrocarbon carcinogenesis  

Microsoft Academic Search

Carcinogenic activation of polycyclic aromatic hydrocarbons (PAH) involves two main pathways: one-electron oxidation and monooxygenation. One-electron oxidation produces PAH radical cations, which can react with cellular nucleophiles. Results from biochemical and biological experiments indicate that only PAH with ionization potentials below ca. 7.35 eV can be metabolically activated by one-electron oxidation. In addition, the radical cations of carcinogenic PAH must

E. Cavalieri; E. Rogan

1985-01-01

153

Diversity and correlation of specific aromatic hydrocarbon biodegradation capabilities  

Microsoft Academic Search

This work investigated the biodegradation capabilitiesof indigenous microorganisms exposed to differentcombinations of aromatic hydrocarbons. Considerablediversity was found in the catabolic specificity of 55strains. Toluene was the most commonly degradedcompound, followed by p-xylene, m-xyleneand ethylbenzene. Strains capable of degradingo-xylene and benzene, which were theleast-frequently-degraded compounds, exhibited broaderbiodegradation capabilities. Kappa statistics showeda significant correlation between the abilities todegrade toluene and ethylbenzene, p-xylene

Nahide Gülensoy; Pedro J. J. Alvarez

1999-01-01

154

Diversity and correlation of specific aromatic hydrocarbon biodegradation capabilities  

Microsoft Academic Search

This work investigated the biodegradation capabilities of indigenous microorganisms exposed to different com- binations of aromatic hydrocarbons. Considerable diversity was found in the catabolic specificity of 55 strains. Toluene was the most commonly degraded compound, followed byp-xylene,m-xylene and ethylbenzene. Strains capable of degrading o-xylene and benzene, which were the least-frequently-degraded compounds, exhibited broader biodegradation capabilities. Kappa statistics showed a significant

Nahide Gülensoy; Pedro J. J. Alvarez

1999-01-01

155

Chromatographic methods for carcinogenic/mutagenic nitropolycyclic aromatic hydrocarbons.  

PubMed

Nitropolycyclic aromatic hydrocarbons (NPAHs), which are known to be carcinogenic and/or mutagenic, are considered to be one of the air pollutants that cause lung cancer. In the last two decades, a number of sensitive and selective methods have been developed for the determination of NPAHs and related compounds in environmental and biological samples. This paper describes the state of the art of the methods and applications. PMID:11002277

Hayakawa, K

2000-10-01

156

Quantification of nitrated polynuclear aromatic hydrocarbons in atmospheric particulate matter  

Microsoft Academic Search

A derivatization-GC\\/ECD analytical method has been developed. This method involves first the reduction of nitrated polynuclear aromatic hydrocarbons (NPAHs) to their corresponding amino-PAHs by NaBH4. This is followed by derivatization of the amino-PAHs with heptafluorobutyric anhydride (HFBA). Such derivatization provides a polyfluorinated tag to the NPAHs, which can then be detected and quantified at pg levels by GC\\/ECD. Using this

Xu Jinhui; Frank S. C Lee

2000-01-01

157

Reductive hydrogenation of polycyclic aromatic hydrocarbons catalyzed by metalloporphyrins  

Microsoft Academic Search

The hydrogenation of polycyclic aromatic hydrocarbons (PAHs) (naphthalene, anthracene, and phenanthrene) catalyzed by metalloporphyrins based on cobalt, nickel or iron was studied in aqueous solutions at room temperature and ambient pressure. Nickel porphyrin (P1) activated by nanosized zero-valent iron (nano-ZVI) and cobalt porphyrins (P2) and (P4) activated by titanium(III) citrate as the electron donor were demonstrated to be promising catalysts

Elza Nelkenbaum; Ishai Dror; Brian Berkowitz

2007-01-01

158

Critically Evaluated Thermochemical Properties of Polycyclic Aromatic Hydrocarbons  

NASA Astrophysics Data System (ADS)

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

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

2008-12-01

159

Modeling Galactic Extinction with Dust and "Real" Polycyclic Aromatic Hydrocarbons  

NASA Astrophysics Data System (ADS)

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 × 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.

Mulas, Giacomo; Zonca, Alberto; Casu, Silvia; Cecchi-Pestellini, Cesare

2013-07-01

160

QSARs for aromatic hydrocarbons at several trophic levels.  

PubMed

Quantitative structure-activity relationships (QSARs) with aromatic hydrocarbons were obtained. Biological response was measured by acute toxicity of several aquatic trophic levels. The chemicals assayed were benzene, toluene, ethylbenzene, o-xylene, m-xylene, p-xylene, isopropylbenzene, n-propylbenzene, and butylbenzene. Acute toxicity tests were carried out with Scenedesmus quadricauda, as representative of primary producers; Daphnia spinulata, a zooplanctonic cladoceran; Hyalella curvispina, a benthic macroinvertebrate; and Bryconamericus iheringii, an omnivorous native fish. The EC50 or LC50 was calculated from analytical determinations of aromatic hydrocarbons. Nonlinear regression analysis between the logarithm of the octanol-water partition coefficient (log Kow) of each compounds and the toxicity end points was performed. QSARs were positively related to increases in log Kow at all trophic levels. Intertaxonomic differences were found in comparisons of algae with animals and of invertebrates with vertebrates. We observed that these differences were not significant with a log Kow higher than 3 for all organisms. Aromatic hydrocarbons with log Kow values of less than 3 showed different toxicity responses, with algae more resistant than fish and invertebrates. We concluded that this was a result of the narcotic mode of action related to liposolubility and the ability of the compound to reach its target site in the cell. The bioconcentration factor (BCF) achieved to start nonpolar narcosis fell almost 1 order of magnitude below the BCF expected from the log Kow. Predicted critical body residues for nonpolar narcosis ranged between 2 and 1 mM. PMID:16528686

Di Marzio, Walter; Saenz, Maria Elena

2006-04-01

161

Occurrence of polycyclic aromatic hydrocarbons in smoked cheese.  

PubMed

The presence of polycyclic aromatic hydrocarbons (PAH) in smoked cheeses of different origin was studied. The samples were subjected to an initial extraction of fat and an alkaline treatment, extracted with cyclohexane, cleaned up by means of solid-phase extraction tubes, and analyzed by gas chromatography/mass spectrometry (GC/MS) operating in selective ion-monitoring mode (SIM). The results revealed the presence of numerous polycyclic aromatic hydrocarbons in the exterior zone of the samples, some of them with methyl groups. In all cases, the concentrations of compounds of low molecular weight were much higher than those of high molecular weight. Polycyclic aromatic hydrocarbons with varying degrees of carcinogenicity were identified, including benzo(a)pyrene in concentrations, which, although they did not exceed the limit established for this compound in the rind of ripened cheeses, do exceed the limit of 0.03 microg/kg fixed for other foods smoked with smoke flavorings. Significant differences in the number and concentration of PAH in smoked cheese also were observed from rind to interior, the rind being the most contaminated zone. PMID:15202639

Guillén, María D; Sopelana, Patricia

2004-03-01

162

Spectroscopic properties of polycyclic aromatic hydrocarbons (PAHs) and astrophysical implications.  

PubMed

PAHs (polycyclic aromatic hydrocarbons) are probably present as a mixture of neutral and ionized species and are responsible for the set of infrared emission bands in the 2-15 microns regions, which are observed in many different objects like reflection and planetary nebulae and external galaxies. PAHs are suggested to be the most abundant free organic molecules and ubiquitous in space. PAHs might also exist in the solid phase, included in interstellar ices in dense clouds. A complex aromatic network is expected on interstellar grains in the diffuse interstellar medium. The existence of an aromatic kerogen-like structure in carbonaceous meteorites and its similarity with interstellar spectra suggests a link between interstellar matter and primitive Solar System bodies. PMID:11541329

d'Hendecourt, L; Ehrenfreund, P

1997-01-01

163

EVALUATION OF SAMPLING AND ANALYTICAL METHODOLOGY FOR POLYNUCLEAR AROMATIC COMPOUNDS IN INDOOR AIR  

EPA Science Inventory

The objective of this project was to develop a generic sampling and analytical methodology to characterize the polynuclear aromatic hydrocarbon (PAH) concentrations in air within various microenvironments. The following three studies were performed: evaluation of analytical metho...

164

Fog processing of polycyclic aromatic hydrocarbons (PAH)  

NASA Astrophysics Data System (ADS)

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.

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

2010-07-01

165

Field Evaluation of Sampling and Analysis for Organic Pollutants in Indoor Air,  

National Technical Information Service (NTIS)

The objectives of the study were to determine the feasibility of the use of newly developed indoor air samplers in residential indoor air sampling and to evaluate methodology for characterization of the concentrations of polynuclear aromatic hydrocarbons ...

J. C. Chuang G. A. Mack J. W. Stockrahm S. W. Hannan C. Bridges

1988-01-01

166

Enzymatic and genetic profiles in environmental strains grown on polycyclic aromatic hydrocarbons  

Microsoft Academic Search

The possible generation of oxidative stress induced by aromatic hydrocarbon degradation suggests that ancillary enzyme activities\\u000a could facilitate the utilization of polycyclic aromatic hydrocarbons as sole carbon source. To investigate the metabolic profiles\\u000a of low molecular weight polycyclic aromatic hydrocarbon-degrading strains of Sphingobium chlorophenolicum, Rhodococcus\\u000a aetherovorans, Rhodococcus opacus and Mycobacterium smegmatis, the determination of the activity of putative detoxifying enzymes

Lucia Cavalca; Nicoletta Guerrieri; Milena Colombo; Silvia Pagani; Vincenza Andreoni

2007-01-01

167

Atmospheric chlorinated polycyclic aromatic hydrocarbons in East Asia.  

PubMed

This study estimates atmospheric concentrations of chlorinated polycyclic aromatic hydrocarbons (ClPAHs) and polycyclic aromatic hydrocarbons (PAHs) in East Asia using a Gas Chromatograph with High Resolution Mass Spectrometer (GC-HRMS). ClPAHs are ubiquitously generated from PAHs through substitution, and some ClPAHs show higher aryl hydrocarbon receptor (AhR)-mediated activities than their parent PAHs. Atmospheric particles were collected using a high-volume air sampler equipped with a quartz-fiber filter. We determined the ClPAH concentrations of atmospheric particles collected in Japan (Sapporo, Sagamihara, Kanazawa, and Kitakyushu), Korea (Busan), and China (Beijing). The concentrations of ClPAHs were highest in the winter Beijing sample, where the total mean concentration was approximately 15-70 times higher than in the winter samples from Japan and Korea. The concentrations of ?19ClPAHs and ?9PAHs were significantly correlated in the Kanazawa and the Busan samples. This indicates that within those cities ClPAHs and PAHs share the same origin, implying direct chlorination of parent PAHs. Toxic equivalent concentrations (TEQs) of the total ClPAHs and PAHs were lowest in Kanazawa in the summer, reaching 1.18 and 2610fg-TEQm(-3) respectively, and highest in Beijing in the winter, reaching 627 and 4240000fg-TEQm(-3) respectively. PMID:24997898

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

2014-09-01

168

Lymphocyte aromatic hydrocarbon responsiveness in acute leukemia of childhood  

SciTech Connect

Aryl hydrocarbon hydroxylase (AHH) activity and inducibility were examined in mitogen-stimulated cultured lymphocytes from children with acute leukemia in remission, with nonleukemic malignancies, and with no family or personal history of malignant disease. Neither morphological differences nor differences in mitogen responsivelness were observed among the three sources of cells studied. Levels of constitutive and dibenzanthracene-induced AHH activity were found to be similar among the three groups by analysis of variance. However, when results were analyzed in terms of inducibility ratios, it was found that cells from leukemic children were significantly less inducible (p < 0.005) than cells from unaffected children or children with nonleukemic malignancies. The reason for this difference became apparent when statistical criteria were employed for the phenotypic separation of individuals who were highly aromatic hydrocarbon responsive and minimally responsive. A significantly larger proportion (p < 0.001) of leukemic children than unaffected children or children with nonleukemic malignancy were found to be minimally aromatic hydrocarbon responsive. Moreover, in patients with acute lymphoblastic leukemia relapsing while on therapy, longer durations of the first remission were correlated (r = 0.63, p < 0.05) with the highly inducible AHH phenotype.

Blumer, J.L. (Rainbow Babies and Children's Hospital, Cleveland, OH); Dunn, R.; Esterhay, M.D.; Yamashita, T.S.; Gross, S.

1981-12-01

169

Abiotic synthesis of polycyclic aromatic hydrocarbons on Mars  

NASA Astrophysics Data System (ADS)

Thermochemical calculations of metastable equilibria are used to evaluate the stability of condensed polycyclic aromatic hydrocarbons (PAHs) in cooling thermal gases and hydrothermal fluids on ancient Mars, which are roughly similar to their terrestrial counterparts. The effects of temperature, pressure, the extent of PAH alkylation, and the relative stability of PAHs and alkanes are considered. Inhibition of methane and graphite formation favors synthesis of metastable mixtures of hydrocarbons from aqueous or gaseous CO, CO2, and H2 below 200°-300°C. High-temperature quenching of H2 and CO in volcanic and impact gases and dynamic hydrothermal fluids also favor the synthesis of hydrocarbons. In addition, an excess of CO in cooling systems relative to equilibrium makes the synthesis from CO and H2 more favorable energetically than from CO2 and H2. Both the CO-H2 reactions through Fischer-Tropsch (FT) type processes and the CO2-H2 reactions could be catalyzed by magnetite. Volcanic gases and hydrothermal fluids related to mafic and ultramafic magmas and rocks are more favorable for FT type synthesis than those associated with oxidized Fe2O3-bearing rocks and regolith. We conclude that PAHs and aliphatic hydrocarbons on Mars and Earth could be formed without the contribution of biogenic carbon. Some PAHs could be formed because of pyrolysis of other hydrocarbons formed earlier by the FT type synthesis or other processes. If the PAHs found in the ALH 84001 martian meteorite formed together with other hydrocarbons through FT type synthesis, it may be possible to bracket the temperature of the synthesis. The approach presented here can be generalized to study the synthesis of hydrocarbons in terrestrial volcanic and hydrothermal processes.

Zolotov, Mikhail; Shock, Everett

1999-06-01

170

The high-temperature oxidation of aromatic hydrocarbons  

NASA Technical Reports Server (NTRS)

Chemical mechanisms of the atmospheric pressure, high-temperature (875-1500 K) gas-phase oxidation of benzene, toluene, ethylbenzene, and propylbenzene are described and discussed. Oxidation trends evident from turbulent flow reactor experiments serve as the basis for the mechanisms of the oxidation of benzene and alkylated aromatics. The potential effects of very high temperatures and pressures on the chemistry of oxidation of aromatics are described. The oxidation of benzene and phenyl radical has been found to proceed in a stepwise C6-C5-C4 sequence. Species profiles obtained from flow-reactor experiments suggest that the oxidation of benzene and phenyl radical follows the generalized route via phenoxy, cyclopentadienyl and butadienyl radical. The oxidation of the C4 species branches into multiple pathways that yield copious amounts of ethylene and acetylene. Certain major trends are evident: the alkylated aromatics on initial attack either form styrene, benzyl radical or benzene. The styrene reacts further to produce a benzyl radical or benzene. The oxidation of an alkylated aromatic hydrocarbon appears eventually to reduce to the oxidation of either phenyl radical or benzene.

Brezinsky, K.

1986-01-01

171

Fluorescence quenching studies of nitrated polycyclic aromatic hydrocarbons.  

PubMed

The analysis of nitrated polycyclic aromatic hydrocarbons (NPAHs) is of great importance because of the mutagenicity and possible carcinogenic activity of these compounds, which are distributed widely in the environment. Nitro-substituents in aromatic compounds are known to quench fluorescence and NPAHs have no intrinsic fluorescence, but they can be determined using their quenching effects on other fluorophores. The quenching effects of several important NPAHs on 1,2,3,4- tetrahydro-1-naphthol,5,6,7,8-tetrahydro-1-naphthol,4-(2-hydroxy-4-sulfo-1-naphthylazo)-2-naphthalene carboxylic acid and 7-amino-4-methyl coumarin have been studied. The singlet emission of these fluorophores is efficiently quenched by all the NPAHs, the quenching following the Stern-Volmer relationship. Quenching constants and the limits of detection and linear ranges of the quenchers have been determined in each case: the limits of detection are ca 1?µm. PMID:20354970

Al-Kindy, Salma M Z; Miller, James N

2011-01-01

172

Stability of multiply charged clusters of polycyclic aromatic hydrocarbons  

NASA Astrophysics Data System (ADS)

The stability of multiply charged clusters of polycyclic aromatic hydrocarbons (PAHs) is theoretically investigated. We propose a new model (stacked structure model) for fragmentation of PAH clusters. The appearance size, a minimum cluster size such that the cluster remains stable when multiply ionized, is calculated by our new model as well as by the conventional liquid drop model. The appearance sizes for doubly charged clusters of anthracene and coronene calculated by the two models are found to be much smaller than those observed in the experiments. Possible reasons for the discrepancy are discussed.

Nakamura, Masato; Ichimura, Atsushi

2013-09-01

173

Polycyclic aromatic hydrocarbon-DNA adduct formation in prostate carcinogenesis  

PubMed Central

The evidence for polycyclic aromatic hydrocarbons (PAH) playing a role in prostate carcinogenesis comes mainly from associations between reported PAH exposures and prostate cancer in epidemiologic studies. Associations between prostate cancer and DNA repair genotypes and phenotypes have also been reported, lending further credence to a PAH-induced carcinogenesis pathway in prostate cancer. Recent work that demonstrates the human prostate has metabolic enzyme activity necessary for PAH activation and will form DNA adducts upon exposure to PAH further supports PAH carcinogenesis. We have demonstrated the presence of PAH-DNA adducts in prostate cancer cases, but further validation of this biomarker as a carcinogenic agent in human prostate is needed.

Rybicki, Benjamin A.; Nock, Nora L.; Savera, Adnan T.; Tang, Deliang; Rundle, Andrew

2006-01-01

174

Extraction Techniques for Polycyclic Aromatic Hydrocarbons in Soils  

PubMed Central

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.

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

2010-01-01

175

Fragmentation dynamics of excited ionized polycyclic aromatic hydrocarbons  

NASA Astrophysics Data System (ADS)

We have theoretically evaluated the fragmentation of excited and ionized polycyclic aromatic hydrocarbons (PAH) and clusters of PAHs. In particular the stability of neutral and positively charged coronene has been studied as a prototype of PAH. We present in this communication vertical and adiabatic ionization potentials with charge up to 6 and dissociation energies and fragmentation paths of several channels: H/H, H2, H+/H and H+/H+ loss. We present as well results corresponding to the fragmentation dynamics of singly-ionized clusters of pyrene.

Paris, C.; Silva, H., Jr.; Díaz-Tendero, S.; Rapacioli, M.; Spiegelman, F.; Martín, F.; Alcamí, M.

2014-04-01

176

Determination of polycyclic aromatic hydrocarbons in the lung  

Microsoft Academic Search

Polycyclie aromatic hydrocarbons (PAHs) accumulated in human lung samples from men (n = 236) and women (n = 128) were determined by high-performance liquid chromatography (HPLC) to examine their association with lung cancer. The mean values for benzo[a]pyrene (BaP), benzo[k]fluoranthene (BkF), and benzo[g,h,i]perylene (BghiP) in lungs (ng\\/g dry lung) of Japanese autopsied patients were 0.54, 0.44, and 0.87, respectively. The

Hiroshi Seto; Tomoko Ohkubo; Takako Kanoh; Morio Koike; Kyoji Nakamura; Yutaka Kawahara

1993-01-01

177

Anharmonicity and the interstellar polycyclic aromatic hydrocarbon infrared emission spectrum  

NASA Technical Reports Server (NTRS)

The hypothesis that interstellar infrared emission originates from vibrationally excited polycyclic aromatic hydrocarbons (PAHs) requires that emission can arise from all vibrational levels that are energetically accessible. Due to anharmonicity, the emission from the upper vibrational levels is shifted to longer wavelengths from that of the v = 1-0 transition. It is shown that structure in the 3-micron region is readily and quantitatively explained by emission from upper vibrational levels of excited PAHs that contain a maximum of 20-30 carbon atoms. The asymmetrical broadening of the 11.3-micron emission band may also be due to anharmonicity.

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

1987-01-01

178

Polycyclic aromatic hydrocarbons in soils of Vasilievsky Island (St. Petersburg)  

NASA Astrophysics Data System (ADS)

The composition and accumulation patterns of priority polycyclic aromatic hydrocarbons (PAHs) in soils of Vasilievsky Island in Saint Petersburg were studied. Concentrations of benzo[a]pyrene were found to exceed maximum permissible concentrations in all the samples, and the maximum recorded concentration exceeded the MPC by 50 times. Concentrations of other PAHs also exceeded the background values. The main soil pollutants were found to be fluoranthene, pyrene, benzo[b]fluoranthene, benzo[a]pyrene, and benzo[g, h, i] perylene, the part of which in the total content of PAHs was 65-80%.

Lodygin, E. D.; Chukov, S. N.; Beznosikov, V. A.; Gabov, D. N.

2008-12-01

179

Monocyclic Aromatic Hydrocarbons in Kathmandu During the Winter Season  

Microsoft Academic Search

Mixing ratios of seven monocyclic aromatic hydrocarbons, as well as NO2, SO2 and O3, were measured by long path differential optical absorption spectroscopy (DOAS) at a suburban site in Kathmandu, Nepal, during\\u000a Jan.–Feb. 2003. The results showed average benzene (3.9?±?1.8 ppbv), toluene (13.3?±?7.1 ppbv), and sum of xylene isomers\\u000a (42.2?±?15.7 ppbv) mixing ratios in Kathmandu. The xylenes concentrations were higher than in the

Yong Yu; Arnico Panday; Elke Hodson; Bo Galle; Ronald Prinn

2008-01-01

180

Polycyclic aromatic hydrocarbons and the diffuse interstellar bands  

NASA Technical Reports Server (NTRS)

This paper discusses some of the thermodynamic and spectroscopic properties of polycyclic aromatic hydrocarbons which make them attractive candidates as carriers of the Diffuse Interstellar Bands (DIBs). It is pointed out that, in the diffuse medium, many of these species will be partially hydrogenated and positively charged, and will absorb in the visible. The observed lineshapes and widths of the DIBs can be explained by rovibronic band contours and linebroadening due to internal conversion. Since little information is available concerning the spectroscopic properties of such species in the gas phase, a considerable amount of laboratory and theoretical work is needed.

Van Der Zwet, G. P.; Allamandola, L. J.

1985-01-01

181

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

PubMed

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

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

2009-02-01

182

Magnetic molecules created by hydrogenation of polycyclic aromatic hydrocarbons  

NASA Astrophysics Data System (ADS)

Present routes to produce magnetic organic-based materials adopt a common strategy: the use of magnetic species (atoms, polyradicals, etc.) as building blocks. We explore an alternative approach which consists of selective hydrogenation of polycyclic aromatic hydrocarbons. Self-consistent-field (SCF) (Hartree-Fock and density-functional theory) and multiconfigurational (configuration interaction with single- and double-excitation and multiconfigurational SCF) calculations on coronene and corannulene, both hexahydrogenated, show that the formation of stable high spin species is possible. The spin of the ground states is discussed in terms of Hund’s rule and Lieb’s theorem for bipartite lattices (alternant hydrocarbons in this case). This proposal opens a door to magnetism in the organic world.

Vergés, J. A.; Chiappe, G.; Louis, E.; Pastor-Abia, L.; Sanfabián, E.

2009-03-01

183

Polycyclic aromatic hydrocarbons - Primitive pigment systems in the prebiotic environment  

NASA Technical Reports Server (NTRS)

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.

Deamer, D. W.

1992-01-01

184

Effects of co-occurring aromatic hydrocarbons on degradation of individual polycyclic aromatic hydrocarbons in marine sediment slurries  

SciTech Connect

Rates of polycyclic aromatic hydrocarbon (PAH) degradation and mineralization were influenced by preexposure to alternate PAHs and a monoaromatic hydrocarbon at relatively high (100 ppm) concentrations in organic-rich aerobic marine sediments. Prior exposure to three PAHs and benzene resulted in enhanced (/sup 14/C)naphthalene mineralization, while (/sup 14/C)anthracene mineralization was stimulated only by benzene and anthracene preexposure. Preexposure of sediment slurries to phenanthrene stimulated the initial degradation of anthracene. Prior exposure to naphthalene stimulated the initial degradation of phenanthrene but had no effect on either the initial degradation of mineralization of anthracene. For those compounds which stimulated (/sup 14/C)anthracene of (/sup 14/C)naphthalene mineralization, longer preexposures (2 weeks) to alternative aromatic hydrocarbons resulted in an even greater stimulation response. Enrichment with individual PAHs followed by subsequent incubation with one or two PAHs showed no alteration in degradation patterns due to the simultaneous presence of PAHs. The evidence suggests that exposure of marine sediments to a particular PAH or benzene results in the enhanced ability of these sediments to subsequently degrade that PAH as well as certain other PAHs. The enhanced degradation of a particular PAH after sediments have been exposed to it may result from the selection and proliferation of specific microbial populations capable of degrading it.

Bauer, J.E.; Capone, D.G.

1988-07-01

185

Polycyclic aromatic hydrocarbons as plausible prebiotic membrane components.  

PubMed

Aromatic molecules delivered to the young Earth during the heavy bombardment phase in the early history of our solar system were likely to be among the most abundant and stable organic compounds available. The Aromatic World hypothesis suggests that aromatic molecules might function as container elements, energy transduction elements and templating genetic components for early life forms. To investigate the possible role of aromatic molecules as container elements, we incorporated different polycyclic aromatic hydrocarbons (PAH) in the membranes of fatty acid vesicles. The goal was to determine whether PAH could function as a stabilizing agent, similar to the role that cholesterol plays in membranes today. We studied vesicle size distribution, critical vesicle concentration and permeability of the bilayers using C(6)-C(10) fatty acids mixed with amphiphilic PAH derivatives such as 1-hydroxypyrene, 9-anthracene carboxylic acid and 1,4 chrysene quinone. Dynamic Light Scattering (DLS) spectroscopy was used to measure the size distribution of vesicles and incorporation of PAH species was established by phase-contrast and epifluorescence microscopy. We employed conductimetric titration to determine the minimal concentration at which fatty acids could form stable vesicles in the presence of PAHs. We found that oxidized PAH derivatives can be incorporated into decanoic acid (DA) vesicle bilayers in mole ratios up to 1:10 (PAH:DA). Vesicle size distribution and critical vesicle concentration were largely unaffected by PAH incorporation, but 1-hydroxypyrene and 9-anthracene carboxylic acid lowered the permeability of fatty acid bilayers to small solutes up to 4-fold. These data represent the first indication of a cholesterol-like stabilizing effect of oxidized PAH derivatives in a simulated prebiotic membrane. PMID:22798228

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

2012-08-01

186

Polycyclic Aromatic Hydrocarbons as Plausible Prebiotic Membrane Components  

NASA Astrophysics Data System (ADS)

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

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

2012-08-01

187

Exploratory study of particle-bound polycyclic aromatic hydrocarbons in different environments of Mexico City  

NASA Astrophysics Data System (ADS)

Several studies regarding particulate matter in air pollution have been performed in Mexico City, but none have focused on environment exposure to particle-bound polycyclic aromatic hydrocarbons (PPAH), which are related to the occurrence of cardiopulmonary diseases and mortality. On this account, this study presents measurements of personal exposure to PPAH in different outdoor and indoor environments, as well as along roadways in Mexico City. The measurements were done with portable sensors based on photoelectric charging and diffusion charging to determine the PPAH concentrations and the joint active surface of all particles, respectively. The use of these two sensors in parallel is a useful tool to qualitatively identify the major sources and to describe the physical and chemical characteristics of the particles. The highest exposures were found in ambient air near traffic sources, mainly at sites with great influence of diesel vehicles, such as urban transfer bus stations. Roadway measurements showed that Mexican PPAH pollution levels are between those in large cities in Europe and USA. For indoor environments such as residences, shopping centers, restaurants and hospitality venues, it was found that secondhand smoke is the major contributor, however badly calibrated pilot stoves, inefficient ventilation and faulty air-conditioning systems can be additional sources of PPAH.

Velasco, Erik; Siegmann, Philip; Siegmann, Hans C.

188

MTBE and aromatic hydrocarbons in North Carolina stormwater runoff.  

PubMed

A total of 249 stormwater samples were collected from 46 different sampling locations in North Carolina over an approximate 1-year period and analyzed to identify land use types where fuel oxygenates and aromatic hydrocarbons may be present in higher concentrations and at greater frequency. Samples were analyzed by gas chromatography-mass spectrometry in ion selective mode to achieve a quantitation limit of 0.05 microg/l. m-,p-Xylene and toluene were detected in over half of all samples analyzed, followed by MTBE: o-xylene: 1,3,5-trimethylbenzene: ethylbenzene; and 1,2,4-trimethylbenzene. Benzene, DIPE, TAME and 1,2,3-trimethylbenzene were detected in < 10% of the samples analyzed. Median contaminant concentrations (when detected) varied from 0.07 microg/l for ethylbenzene to 0.11 microg/l for toluene. All of the locations with significantly higher contaminant concentrations were associated with direct runoff from a gas station or discharge of contaminated groundwater from a former leaking underground storage tank. For all of the aromatic hydrocarbons, the maximum observed contaminant concentrations were over an order of magnitude lower than current drinking water standards. PMID:11996377

Borden, Robert C; Black, David C; McBlief, Kathleen V

2002-01-01

189

Formation of polycyclic aromatic hydrocarbons in circumstellar envelopes  

NASA Technical Reports Server (NTRS)

Production of polycyclic aromatic hydrocarbons in carbon-rich circumstellar envelopes was investigated using a kinetic approach. A detailed chemical reaction mechanism of gas-phase PAH formation and growth, containing approximately 100 reactions of 40 species, was numerically solved under the physical conditions expected in cool stellar winds. The chemistry is based on studies of soot production in hydrocarbon pyrolysis and combustion. Several first-ring and second-ring cyclization processes were considered. A linear lumping algorithm was used to describe PAH growth beyond the second aromatic ring. PAH production using this mechanism was examined with respect to a grid of idealized constant velocity stellar winds as well as several published astrophysical models. The basic result is that the onset of PAH production in the interstellar envelopes is predicted to occur within the temperature interval of 1100 to 900 K. The absolute amounts of the PAHs formed, however, are very sensitive to a number of parameters, both chemical and astrophysical, whose values are not accurately known. Astrophysically meaningful quantities of PAHs require particularly dense and slow stellar winds and high initial acetylene abundance. It is suggested that most of the PAHs may be produced in a relatively small fraction of carbon-rich red giants.

Frenklach, Michael; Feigelson, Eric D.

1989-01-01

190

Partition characteristics of polycyclic aromatic hydrocarbons on soils and sediments  

USGS Publications Warehouse

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

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

1998-01-01

191

Polycyclic aromatic hydrocarbons: are they a problem in processed oil shales. [254 references  

Microsoft Academic Search

Organic residues from processed oil shales were characterized 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 extracted by

D. L. Maase; V. D. Adams

1983-01-01

192

UV resonance Raman characterization of polycyclic aromatic hydrocarbons in coal liquid distillates  

SciTech Connect

Ultraviolet resonance Raman spectroscopy has been used to characterize the polycyclic aromatic hydrocarbon composition of a series of distillates of coal-derived liquids. The UV Raman spectra easily monitor changes in the polycyclic aromatic hydrocarbon composition as a function of distillation temperature. Specific species, such as pyrene, can be determined by judicious choice of excitation wavelength.

Rumelfanger, R.; Asher, S.A.; Perry, M.B.

1988-02-01

193

Aromatic Hydrocarbons in Generator Shale Resin (Aromaticheskie Uglevodorody v Generatornoi Slantsevoi Smole).  

National Technical Information Service (NTIS)

The group composition and content of aromatic hydrocarbons of shale oil generator resin which boil at temperatures above 300C have been determined previously and the aromatic hydrocarbons of this resin have been analyzed in more detail in other works. In ...

L. Lakhe O. Eizen

1971-01-01

194

Polycyclic aromatic hydrocarbons and nitropolycyclic aromatic hydrocarbons in urban air particulates and their relationship to emission sources in the Pan–Japan Sea countries  

Microsoft Academic Search

Airborne particulates were collected in seven cities in the Pan–Japan Sea countries, Shenyang (China), Vladivostok (Russia), Seoul (South Korea), Kitakyushu, Kanazawa, Tokyo and Sapporo (Japan), in winter and summer from 1997 to 2002. In addition, particulates from domestic coal-burning heaters and diesel engine automobiles were collected in Shenyang and Kanazawa, respectively. Nine polycyclic aromatic hydrocarbons (PAHs) and four nitropolycyclic aromatic

Ning Tang; Tetsuyuki Hattori; Rina Taga; Kazuhiko Igarashi; Xiaoyang Yang; Kenji Tamura; Hitoshi Kakimoto; Vasiliy F. Mishukov; Akira Toriba; Ryoichi Kizu; Kazuichi Hayakawa

2005-01-01

195

Repeated exposure to polycyclic aromatic hydrocarbons and asthma: effect of seroatopy  

PubMed Central

Background Exposure to traffic-related air pollutants, including polycyclic aromatic hydrocarbons (PAHs), can induce asthma. However, the effects of early repeated PAH exposure over time on different asthma phenotypes have not been examined. Objective To assess associations between repeated PAH exposure, measured from prenatal personal and residential indoor monitors in children's homes, and asthma in an inner-city cohort. Methods Prenatal exposure was assessed by personal air monitoring during 48 hours and exposure at 5 to 6 years of age by 2-week residential monitoring in the Columbia Center for Children's Environmental Health cohort. PAH was dichotomized into pyrene (representative semivolatile PAH) and the sum of 8 nonvolatile PAHs. High exposure to each was defined as measures above the median at both repeated time points. Asthma and wheeze were determined by validated questionnaires at ages 5 to 6 years. Children with specific IgE levels greater than 0.35 IU/mL to any of 5 indoor allergens were considered seroatopic. Results Among all 354 children, repeated high exposure to pyrene was associated with asthma (odds ratio [OR], 1.90; 95% confidence interval [CI], 1.13-3.20). Among 242 nonatopic children, but not those sensitized to indoor allergens (n = 87) or with elevated total IgE levels (n = 171), high pyrene levels were associated positively with asthma (OR, 2.89; 95% CI, 1.77-5.69), asthma medication use (OR, 2.28; 95% CI, 1.13-4.59), and emergency department visits for asthma (OR, 2.43; 95% CI, 1.20-4.91). Associations between the levels of the 8 nonvolatile PAHs and asthma were not observed, even when stratifying by seroatopy. Conclusion Nonatopic children may be more susceptible to the respiratory consequences of early pyrene exposures.

Jung, Kyung Hwa; Yan, Beizhan; Moors, Kathleen; Chillrud, Steven N.; Perzanowski, Matthew S.; Whyatt, Robin M.; Hoepner, Lori; Goldstein, Inge; Zhang, Bingzhi; Camann, David; Kinney, Patrick L.; Perera, Frederica P.; Miller, Rachel L.

2012-01-01

196

Formation of polycyclic aromatic hydrocarbons in an atmospheric pressure ethylene diffusion flame  

Microsoft Academic Search

The microstructure of an atmospheric pressure, counterflow, sooting, flat, laminar ethylene diffusion flame has been studied experimentally by withdrawing samples from within the flame using a heated quartz microprobe coupled to an online gas chromatograph\\/mass spectrometer (GC\\/MS). The identities and absolute concentrations of about 60 major, minor, and trace species, including aromatics, substituted aromatics, and polycyclic aromatic hydrocarbons (PAH) have

Nesrin Olten; Selim Senkan

1999-01-01

197

Assessment of Total Aromatic Hydrocarbons, Aliphatic and Polycyclic Aromatic Hydrocarbons in Surface Sediment and Fish from the Gulf of Tunis (Tunisia)  

Microsoft Academic Search

This investigation represents the extensive study of the spatial distribution and sources of hydrocarbons in the Gulf of Tunis. Sediments and fish were sampled within the open sea of the Gulf of Tunis during August 2004. All samples were extracted with organic solvents, separated by silica\\/alumina column chromatography, and analyzed by spectrofluorometry for the determination of total aromatic hydrocarbons (TAH)

Nadia Mzoughi; Lassaad Chouba; Gaëtane Lespes

2010-01-01

198

Magnetic instability and pair binding in aromatic hydrocarbon superconductors.  

PubMed

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 ?-electrons on the carbon atoms of a single molecule are modelled by the one-orbital Hubbard model, and the energy difference [Formula: see text] 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

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

2012-01-01

199

High-energy chemical processes: Laser irradiation of aromatic hydrocarbons  

SciTech Connect

Recent studies of the high-energy photochemical degradation of polycyclic aromatic hydrocarbons (PAHs) in solution have furthered our fundamental understanding of the way in which radiation interacts with matter. A new comprehensive mechanism that unifies many of the seemingly contradictory observations in radiation and photochemistry has been proposed on basis of evidence gathered using specialized techniques such as transient optical spectroscopy and transient dc conductivity. The PAH molecules were activated by two-photon ionization, and behavior of the transient ions were monitored as a function of photon energy. It was found that a greater percentage of ions retain sufficient energy to decompose when higher energy light was used. When these cations decompose they leave a trail of products that establish a ``high-energy`` decomposition pathway that involves proton transfer from the ion, a mechanism hitherto not considered in photoionization processes.

Trifunac, A.D.; Liu, A.D.; Loffredo, D.M.

1994-03-01

200

NMR shifts for polycyclic aromatic hydrocarbons from first-principles  

SciTech Connect

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

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

2009-09-03

201

Destruction and survival of polycyclic aromatic hydrocarbons in active galaxies  

NASA Technical Reports Server (NTRS)

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

Voit, G. M.

1992-01-01

202

Carcinogenic classification of polycyclic aromatic hydrocarbons through theoretical descriptors  

NASA Astrophysics Data System (ADS)

Polycyclic aromatic hydrocarbons (PAHs) constitute an important family of molecules capable of inducing chemical carcinogenesis. In this work we report a comparative structure-activity relationship (SAR) study for 81 PAHs using different methodologies. The recently developed electronic indices methodology (EIM) with quantum descriptors obtained from different semiempirical methods (AM1, PM3, and PM5) was contrasted against more standard pattern recognition methods (PRMs), principal component analysis (PCA), hierarchical cluster analysis (HCA), Kth nearest neighbor (KNN), soft independent modeling of class analogies (SIMCA), and neural networks (NN). Our results show that PRMs validate the statistical value of electronic parameters derived from EIM analysis and their ability to identify active compounds. EIM outperformed more standard SAR methodologies and does not appear to be significantly Hamiltonian-dependent.

Troche, Karla S.; Braga, Scheila F.; Coluci, Vitor R.; Galvão, Douglas S.

203

Magnetic instability and pair binding in aromatic hydrocarbon superconductors  

NASA Astrophysics Data System (ADS)

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 ?-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.

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

2012-12-01

204

Determination of polycyclic aromatic hydrocarbons in Athens atmosphere.  

PubMed

Concentrations of total suspended particulates (TSP), benzene soluble fraction (BSF) and polycyclic aromatic hydrocarbons (PAH) have been determined in ambient air from four different sites in Athens, situated in urban, semi-industrial and industrial areas. GLC analysis has been applied for the determination of PAH, while the CGC/MS technique was used in order to confirm the obtained results. The same PAH pattern was observed for all stations. The identified PAH have been fluoranthene (FLA), pyrene (PYR), benzo(a)anthracene (BaA), chrysene (CHR), benzo(b)fluoranthene (BbF), benzo(k)fluoranthene (BkF), benzo(a)pyrene (BaP), benzo(e)pyrene (BeP) and benzo(ghi)perylene (B(ghi)P). The concentrations of individual PAH ranged from traces to 33 ng m-3 (e.g. same or lower comparing to other large cities). The higher values of PAH were found during adverse meteorological conditions. PMID:3557795

Viras, L G; Siskos, P A; Stephanou, E

1987-01-01

205

Polycyclic aromatic hydrocarbon removal from water by natural fiber sorption.  

PubMed

The use of two natural sorbents, kapok and cattail fibers, were investigated for polycyclic aromatic hydrocarbon (PAH) removal from water. Naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, and fluoranthene were the PAHs studied. For comparative purposes, a commercial polyester fiber sorbent was included in the investigation. The PAH sorption and retention capabilities of the three fibers were determined through batch and continuous-flow experiments under non-competitive and competitive conditions. In the batch experiments, cattail fiber was the most effective sorbent. Kapok fiber provided the lowest PAH retention, while cattail fiber had slightly less PAH retention than polyester fiber. When two PAHs were present in the same system, a competitive effect on the much less hydrophobic PAH was observed. Similar results were obtained in the column experiments, except that polyester fiber performed much poorer on naphthalene. Cattail fiber is a promising sorbent for treating PAH-contaminated water, such as urban runoff. PMID:17824537

Khan, Eakalak; Khaodhir, Sutha; Rotwiron, Paritta

2007-08-01

206

Polycyclic Aromatic Hydrocarbons and Infrared Astrophysics with Spitzer  

NASA Technical Reports Server (NTRS)

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

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

2004-01-01

207

Amperometric Immunosensors for screening of Polycyclic Aromatic Hydrocarbons in water  

NASA Astrophysics Data System (ADS)

An amperometric immunosensor with low limit detection was developed for the screening of polycyclic aromatic hydrocarbons (PAHs) in water. The system was based on detecting the specific substance using an immunological reaction by measuring the chemical responses to specific antibodies. An integrated biochip with a three electrode system was fabricated. Gold was used as the working electrode with platinum was used as the counter electrode. A modified Ag/AgCl reference electrode was employed to enhance the stability of the immunosensors. Indirect competition enzyme-linked immunosorbent assay (ELISA) was carried out within the electrode using alkaline phosphatase (AP) as the labelled-enzyme. The system shows acceptable reproducibility and good stability. The immunosensor exhibited a wide linear response to PAHs. A limit of detection for this sensor was in the range of 1 to 10 ng ml-1 in aqueous sample.

Ahmad, A.; Paschero, A.; Moore, E.

2011-08-01

208

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

SciTech Connect

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

Lopez-Puertas, M.; Funke, B.; Garcia-Comas, M. [Instituto de Astrofisica de Andalucia (CSIC), E-18080 Granada (Spain); Dinelli, B. M. [ISAC-CNR, I-40129 Bologna (Italy); Adriani, A.; D'Aversa, E. [IAPS-INAF, I-00133 Rome (Italy); Moriconi, M. L. [ISAC-CNR, I-00133 Rome (Italy); Boersma, C.; Allamandola, L. J., E-mail: puertas@iaa.es [NASA Ames Research Center, Moffett Field, CA 94035-1000 (United States)

2013-06-20

209

Chemical Kinetics of Polycyclic Aromatic Hydrocarbons in Comet Impacts  

NASA Astrophysics Data System (ADS)

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

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

2004-12-01

210

Autothermal reforming of aliphatic and aromatic hydrocarbon liquids  

NASA Technical Reports Server (NTRS)

Results are presented from a study of the autothermal reforming of paraffins and aromatics over nickel catalysts. The trials were performed to examine the carbon products that appear when steam is passed over hydrocarbon liquids to form H2-rich gases, i.e., the autothermal process (ATR). Attention was given to n-hexane, n-tetradecane, benzene, and benzene solutions of naphthalene with reactant preheat to 1000-1150 F. The carbon-formation limit was sought as a function of the steam-to-carbon and oxygen to carbon molar ratios at constant pressure and the preheat temperatures. The catalyst bed was examined after each trial to identify the locations and types of carbon formed using SEM, thermal gravimetric analysis, and X ray diffraction techniques. The hydrocarbon fuels each had a separate temperature and reaction profile, as well as carbon formation characteristics. No carbon formation was observed in the upper layer of the reactor bed, while both gas phase and surface-grown deposits were present in the lower part. The results are concluded of use in the study of No. 2 fuel oil for ATR feedstock.

Flytzani-Stephanopoulos, M.; Voecks, G. E.

1983-01-01

211

Effect of bioremediation on polycyclic aromatic hydrocarbon residues in soil  

SciTech Connect

Soil contamination (60 mg/g of soil) by a diesel oil (DO) spill was simulated in outdoor lysimeter units and the effect of bioremediation treatment consisting of liming, fertilization, and tilling on the persistence of polycyclic aromatic hydrocarbon (PAH) components of DO was measured. After solvent extraction from soil and class separation on silica gel, PAH components were identified and partially quantified by GC-ITD analysis. Residual mutagenicity and acute toxicity of the contaminated soil was also assessed by Ames and Microtox tests. Bioremediation treatment, while increasing the rate of total hydrocarbon degradation, had an even greater effect on PAH persistence, almost completely eliminating these compounds in 12 weeks. Without bioremediation, 12.5-32.5% of the higher molecular weight PAH were still present at 12 weeks. Mutagenicity and toxicity tests corroborated the above results. After substantial initial mutagenicity and toxicity, the contaminated soil approached the background level of uncontaminated soil after 12 weeks of bioremediation. Detoxification was complete in 20 weeks.

Wang, Xiaoping; Yu, Xiaobing; Bartha, R. (Rutgers, The State Univ. of New Jersey, New Brunswick (USA))

1990-07-01

212

Aliphatic and polycyclic aromatic hydrocarbons in the surface sediments from the Eastern Aegean: assessment and source recognition of petroleum hydrocarbons  

Microsoft Academic Search

Materials and methods  Aliphatic and polycyclic aromatic hydrocarbons (PAHs) were determined in surficial sediments from the Aegean Sea in the Eastern\\u000a Mediterranean in 2008.\\u000a \\u000a \\u000a \\u000a \\u000a Results  Total aliphatic hydrocarbons (n-C12 to n-C35) ranged from 330 to 2,660 ng g-1 dry weight (dwt), while aromatics (19 PAHs) varied between 73.5 and 2,170 ng g-1 dwt. Total concentrations of both aliphatic hydrocarbons and PAHs ranged

L. Tolga Gonul; Filiz Kucuksezgin

213

ExBox: a polycyclic aromatic hydrocarbon scavenger.  

PubMed

A template-directed protocol, which capitalizes on donor-acceptor interactions, is employed to synthesize a semi-rigid cyclophane (ExBox(4+)) that adopts a box-like geometry and is comprised of ?-electron-poor 1,4-phenylene-bridged ("extended") bipyridinium units (ExBIPY(2+)). ExBox(4+) functions as a high-affinity scavenger of an array of different polycyclic aromatic hydrocarbons (PAHs), ranging from two to seven fused rings, as a result of its large, accommodating cavity (approximately 3.5 Å in width and 11.2 Å in length when considering the van der Waals radii) and its ability to form strong non-covalent bonding interactions with ?-electron-rich PAHs in either organic or aqueous media. In all, 11 PAH guests were observed to form inclusion complexes with ExBox(4+), with coronene being the largest included guest. Single-crystal X-ray diffraction data for the 11 inclusion complexes ExBox(4+)?PAH as well as UV/vis spectroscopic data for 10 of the complexes provide evidence of the promiscuity of ExBox(4+) for the various PAHs. Nuclear magnetic resonance spectroscopy and isothermal titration calorimetric analyses of 10 of the inclusion complexes are employed to further characterize the host-guest interactions in solution and determine the degree with which ExBox(4+) binds each PAH compound. As a proof-of-concept, a batch of crude oil from Saudi Arabia was subjected to extraction with the water-soluble form of the PAH receptor, ExBox·4Cl, resulting in the isolation of different aromatic compounds after ExBox·4Cl was regenerated. PMID:22928610

Barnes, Jonathan C; Jurí?ek, Michal; Strutt, Nathan L; Frasconi, Marco; Sampath, Srinivasan; Giesener, Marc A; McGrier, Psaras L; Bruns, Carson J; Stern, Charlotte L; Sarjeant, Amy A; Stoddart, J Fraser

2013-01-01

214

Direct Determination of the Phase Distributions of Semi-VolatilePolycyclic Aromatic Hydrocarbons Using Annular Denuders  

SciTech Connect

An annular denuder-based sampler, here called the integrated organic vapor/particle sampler (IOVPS), has been developed for direct determination of both gas and particulate semi-volatile organic species. The IOVPS uses a cyclone inlet for removal of particles greater than 2.5 micrometers from the airstream, followed by two or three sandblasted glass annular denuders coated with ground particles of an adsorbent resin. The denuders trap the gas phase species of interest before the airstream passes through a filter and a backup denuder. Extracts of the denuders and filters are analyzed for the semi-volatile species of interest. The IOVPS has been tested and validated for sampling semi-volatile polycyclic aromatic hydrocarbons (PAH) in indoor laboratory room air and environmental tobacco smoke (ETS). Ground XAD-4 was the adsorbent for these initial studies. Gas- and particulate-phase concentrations of semi-volatile PAH are presented for these two environments. The new sampler provides the means for directly determining phase distributions of PAH and other classes of semi-volatile organic species, rather than by difference or by techniques that are subject to large positive and negative artifacts. For example, the results obtained with the IOVPS indicate that the volatilization artifact ('blow-off') from particulate PAH collected in indoor laboratory room air with a conventional filter-sorbent bed sampler at face velocity of 33 cm sec-1 led to three-fold underestimation of the particulate fractions of phenanthrene, pyrene and chrysene. Phase distributions for PAH in ETS are also reported here.

Gundel, L.A.; Lee, V.C.; Mahanama, K.R.R.; Stevens, R.K.; Daisey,J.M.

1994-06-01

215

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

EPA Science Inventory

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

216

Chemical Characterization of Polynuclear Aromatic Hydrocarbon Degradation Products from Sampling Artifacts.  

National Technical Information Service (NTIS)

The objective of the study was to characterize the polar components, mainly polynuclear aromatic hydrocarbon (PAH) derivatives, in air samples and to determine whether these compounds are from sampling artifacts or from the sampled air. A literature surve...

J. C. Chuang S. W. Hannan L. E. Slivon

1987-01-01

217

Microbial Degradation of Polycyclic Aromatic Hydrocarbons under Denitrification Conditions in Soil-Water Suspensions: Final Report.  

National Technical Information Service (NTIS)

The microbial degradation of polycyclic aromatic hydrocarbons (PAH) under different redox conditions was examined for soil-water suspensions, with particular emphasis on microbial degradation under denitrification conditions. Batch microbial degradation t...

J. R. Mihelcic R. G. Luthy

1988-01-01

218

Degradation of Selected Polycyclic Aromatic Hydrocarbons in Coastal Sediments: Importance of Microbes and Polychaete Worms.  

National Technical Information Service (NTIS)

Rates of degradation of polycyclic aromatic hydrocarbons (PAH) were examined after addition of crude oil enriched with anthracene, fluoranthene, benz(a)anthracene, and benzo(a)pyrene to coastal sediments in a laboratory (20 degrees) flowing seawater syste...

W. S. Gardner R. F. Lee K. Tenore L. Smith

1978-01-01

219

Biostabilization of Polycyclic Aromatic Hydrocarbons (PAHs) Under Denitrification Conditions in Sediments.  

National Technical Information Service (NTIS)

Carnegie Mellon University and Stanford University investigated the anaerobic biodegradation of polycyclic aromatic hydrocarbons (PAHs) in contaminated sediments under bioslurry denitrifying conditions. Samples from sediment bioslurry tests and toxicity b...

J. T. Bushey I. Ahn U. Ghosh R. G. Luthy T. Mahajan

2000-01-01

220

CHEMICAL ACTIVATION OF NON-MUTAGENIC NITRATED POLYCYCLIC AROMATIC HYDROCARBONS TO MUTAGENS  

EPA Science Inventory

Nitrated polycyclic aromatic hydrocarbons, including carcinogens, may be non-mutagenic in microorganisms because bacterial nitroreductases are unable to reduce their nitro function to proximate mutagenic hydroxylamines. The reduction of the nitro moiety can be accomplished chemic...

221

COMPUTER AUTOMATED EVALUATION OF MUTAGENICITY AND CARCINOGENICITY OF SELECTED POLYCYCLIC AROMATIC HYDROCARBONS  

EPA Science Inventory

The mechanisms by which polycyclic aromatic hydrocarbons (PAHs) induce mutations and cancer have been the subject of considerable attention for several years. arious theoretical and experimental models have been advanced the effects of structural variations on mutagenicity and ca...

222

ANALYSIS OF POLYNUCLEAR AROMATIC HYDROCARBONS IN PARTICULATE MATTER BY LUMINESCENCE TECHNIQUES  

EPA Science Inventory

Fluorescence, phosphorescence, and heavy-metal activated room temperature phosphorescence spectra were obtained for ten polycyclic aromatic hydrocarbon (PAH) reference compounds individually and in mixtures on quartz plates and particulate matter. The results indicate that multic...

223

INDUCTION OF NUCLEAR ANOMALIES IN GASTROINTESTINAL TRACT BY POLYCYCLIC AROMATIC HYDROCARBONS  

EPA Science Inventory

A selective list of polycyclic aromatic hydrocarbons (PAH) with varied carcinogenic and mutagenic potencies, which are identified as common contaminants at superfund clean up sites and neighboring ground water, are investigated for their ability to induce nuclear anomalies (NA) i...

224

Separation and Determination of Hydroxy-Functional Polycyclic Aromatic Hydrocarbons in Coal Liquefaction Materials.  

National Technical Information Service (NTIS)

Recently, an integrated multiple-stage chromatographic method was reported for reducing the chemical complexity of neutral polycyclic aromatic hydrocarbons (PAH) coal liquid isolates by sequentially using distillation, adsorption chromatography and revers...

R. B. Lucke D. W. Later E. K. Chess

1985-01-01

225

Polycyclic Aromatic Hydrocarbon-DNAAdducts in Human Lung and Cancer Susceptibility Genes  

Microsoft Academic Search

Molecular dosimetry for polycyclic aromatic hydrocarbon-DNA ad- ducts, genetic predisposition to cancer, and their interrelationships are under study in numerous laboratories. This report describes a modified •¿?\\

P. G. Shields; E. D. Bowman; A. M. Harrington; V. T. Doan; A. Weston

226

THE PHOTOTOXOICITY OF POLYCYCLIC AROMATIC HYDROCARBONS: A THEORETICAL STUDY OF EXCITED STATES AND CORRELATION TO EXPERIMENT  

EPA Science Inventory

Investigators using models to determine the phototoxic effects of sunlight on polycyclic aromatic hydrocarbons (PAHS) have invoked the excited states of the molecule as important in elucidating the mechanism of these reactions. Energies of actual excited states were calculated fo...

227

THE PHOTOTOXOICITY OF POLYCYCLIC AROMATIC HYDROCARBONS: A THEORETICAL STUDY OF EXCITED STATES AND CORRELATION TO EXPERIMENT  

EPA Science Inventory

Investigators using models to determine the phototoxic effects of sunlight on polycyclic aromatic hydrocarbons (PAHS) have invoked the excited states of the molecule as important in elucidating the mechanism of these reactions. Energies of actual excited states were calcu...

228

Evidence for the extraterrestrial origin of polycyclic aromatic hydrocarbons in the Martian meteorite ALH84001.  

PubMed

Possible sources of terrestrial contamination are considered for the observation of polycyclic aromatic hydrocarbons (PAHs) in the Martian meteorite ALH84001. Contamination is concluded to be negligible. PMID:9809015

Clemett, S J; Dulay, M T; Gillette, J S; Chillier, X D; Mahajan, T B; Zare, R N

1998-01-01

229

Modeling electron and energy transfer processes in collisions between ions and Polycyclic Aromatic Hydrocarbon molecules  

NASA Astrophysics Data System (ADS)

In this work we study collisions between ions and Polycyclic Aromatic Hydrocarbons with the aid of a novel over-the-barrier model and well-established models for nuclear and electronic stopping processes.

Chen, Tao; Alexander, John; Forsberg, Björn; Pettersson, Alf; Gatchell, Michael; Cederquist, Henrik; Zettergren, Henning

2014-04-01

230

Identification and Atmospheric Reactions of Polar Products of Selected Aromatic Hydrocarbons.  

National Technical Information Service (NTIS)

During this experimental program, we have used the facilities and expertise available at the Air Pollution Research Center, University of California, Riverside, to investigate the atmospheric chemistry of selected aromatic hydrocarbons found in California...

2006-01-01

231

METHODOLOGY FOR DETERMINATION OF POLYCYCLIC AROMATIC HYDROCARBONS AND OTHER SEMIVOLATILE ORGANIC COMPOUNDS IN HOUSE DUST  

EPA Science Inventory

Analytical methods were validated to determine polycyclic aromatic hydrocarbons (PAH) and other semivolatile organic compounds in house dust. e also examined the storage stability of three potential markers (solanesol, nicotine, and continine) for particulate-phase environmental ...

232

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

EPA Science Inventory

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

233

EPA (ENVIONMENTAL PROTECTION AGENCY) METHOD STUDY 20, METHOD 610--PNA'S (POLYNUCLEAR AROMATIC HYDROCARBONS)  

EPA Science Inventory

Sixteen laboratories participated in an interlaboratory study conducted to provide precision and accuracy statements for the proposed EPA Method 610 for 16 selected polynuclear aromatic hydrocarbons(PNA's) which may be present in municipal and industrial aqueous discharges. Metho...

234

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

PubMed

The coastal lagoons are vulnerable systems, located between the land and the sea, enriched by both marine and continental inputs and are among the most productive aquatic ecosystems. The purpose of this work is to understand the influence of the lagoon area sediments on the behaviour of polycyclic aromatic hydrocarbons, through the adsorption coefficient determination. In fact, the sorption of polycyclic aromatic hydrocarbons is an important process because it governs the fate, transport, bioavailability and toxicity of these compounds in sediments. It has been observed that the adsorption of polycyclic aromatic hydrocarbons in a transitional system is the outcome of different factors, such as their sources and physicochemical properties, salinity and sediment composition, hydrology and environmental conditions. The results showed that transitional areas contribute to the polycyclic aromatic hydrocarbon accumulation in the sediment turning it into a trap. PMID:24997903

Marini, Mauro; Frapiccini, Emanuela

2014-09-01

235

Cytotoxicity in Human Skin Fibroblasts Induced by Photoactivated Polycyclic Aromatic Hydrocarbons.  

National Technical Information Service (NTIS)

Polycyclic aromatic hydrocarbons (PAH) require chemical modification in order to exert their mutagenic/carcinogenic activity on biological systems. The mode of activation which has been most extensively studied involves enzyme-catalyzed oxidation reaction...

G. F. Strniste R. J. Brake

1980-01-01

236

Public Health Impacts of Secondary Particulate Formation from Aromatic Hydrocarbons in Gasoline  

EPA Science Inventory

Background: Aromatic hydrocarbons emitted from gasoline-powered vehicles contribute to the formation of secondary organic aerosol (SOA), which increases the atmospheric mass concentration of fine particles (PM2.5). Here we estimate the public health burden associated w...

237

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

EPA Science Inventory

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

238

EVALUATION OF POLYURETHANE FOAM CARTRIDGES FOR MEASUREMENT OF POLYNUCLEAR AROMATIC HYDROCARBONS IN AIR  

EPA Science Inventory

The objective of this project was to evaluate polyurethane foam (PUF) cartridges as collection media for quantification of vapor phase polynuclear aromatic hydrocarbons (PAHs) in air. Two cleanup methods for PUF cartridges--compression rinsing and combined compression rinsing and...

239

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

EPA Science Inventory

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

240

Extraction and Determination of Selected Polycyclic Aromatic Hydrocarbons in Plant Tissues.  

National Technical Information Service (NTIS)

A procedure has been developed for analysis of plant material for polycyclic aromatic hydrocarbons (PAHs). Sonication is used to extract the PAHs from homogenized plant material into acetonitrile and then the PAHs are partitioned into pentane. The pentane...

J. T. Coates A. W. Elzerman A. W. Garrison

1986-01-01

241

The Exobiological Role of Interstellar Polycyclic Aromatic Hydrocarbons and Ices  

NASA Technical Reports Server (NTRS)

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 "biogenic" molecules. Although interesting from a chemical and astrophysical standpoint, in the absence of a mechanism by which this population can be dislodged from the precipitous thermodynamic well afforded by their extensive aromatic networks, they are of little Astrobiological significance. Consequently, for the remainder of the talk, we will consider the photochemical evolution of PANS under conditions similar to those found in the ISM and in proto-planetary systems with an eye toward means by which this rich repository of pre-biotic organic "ore" might be converted into materials of greater importance to Astrobiology.

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

2002-01-01

242

Complications with remediation strategies involving the biodegradation and detoxification of recalcitrant contaminant aromatic hydrocarbons  

Microsoft Academic Search

Environmentally persistent aromatic hydrocarbons known as unresolved complex mixtures (UCMs) derived from crude oil can be accumulated by, and elicit toxicological responses in, marine organisms (e.g. mussels, Mytilus edulis). Comprehensive two-dimensional gas chromatography time-of-flight mass-spectrometry (GC×GC–ToF-MS) previously revealed that these UCMs included highly branched alkylated aromatic hydrocarbons. Here, the effects of biodegradation on the toxicity and chemical composition of an

Max Frenzel; Alan Scarlett; Steven J. Rowland; Tamara S. Galloway; Sara K. Burton; Hilary M. Lappin-Scott; Andy M. Booth

2010-01-01

243

The aromatic hydrocarbon receptor, transcription, and endocrine aspects of dioxin action  

Microsoft Academic Search

The widespread and persistent environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin elicits adaptive and adverse biological responses by inducing changes in gene transcription. Some of dioxin's effect reflect disruption of endocrine homeostatis. The aromatic hydrocarbon receptor protein, together with its heterodimerization partner, the aromatic hydrocarbon receptor nuclear translocator protein, mediates dioxin action. There are notable similarities between the mechanism of dioxin action and the

Steven T. Okino; James P. Whitlock

2000-01-01

244

Characterization of the Aromatic Hydrocarbon Receptor Gene and Its Expression in Atlantic Tomcod  

Microsoft Academic Search

Cytochrome P4501A1 (CYP1A1) mRNA is not inducible in Atlantic tomcod from the Hudson River that are treated with halogenated aromatic hydrocarbons (HAHs). In contrast, CYP1A1 mRNA is inducible in Hudson River tomcod that are treated with polycyclic aromatic hydrocarbons (PAHs) and in tomcod that are collected from cleaner rivers and treated with HAHs or PAHs. We hypothesize that CYP1A1 transcription

Nirmal K. Roy; Isaac Wirgin

1997-01-01

245

Electrochemiluminescence Determination of Nitro Polycyclic-Aromatic Hydrocarbons Using HPLC Separation  

Microsoft Academic Search

Summary In order to analyse nitro-polycyclic aromatic hydrocarbons (NPAHs), the NPAHs were reduced to amino-polycyclic aromatic hydrocarbons (APAHs), separated by HPLC and monitored with electrochemiluminescence detection (ECL). Based on a post-column reaction with bis(2,4,6-trichlorophenyl) oxalate, the ECL observations of APAHs were performed in hydrogen peroxide solution, which was electrogenerated from an electrolysis flow cell equipped with a reticulated vitreous carbon

X. Chen; M. J. Li; C. Q. Yi; Y. Tao; X. R. Wang

2003-01-01

246

Aliphatic and Aromatic Hydrocarbons in Sediments of Santos and Cananéia, SP, Brazil  

Microsoft Academic Search

Sediment samples from Santos and Cananéia, São Paulo Brazil were analysed by GC–FID and GC–MS for aliphatic and aromatic hydrocarbons in order to gather information on the degree of contamination by oil and other biogenic contributions. Concentrations of total n-alkanes in Santos varied from 1.05 to 4.29?gg?1 and aromatic hydrocarbons from 0.08 to 42.39?gg?1. In Cananéia total n-alkanes varied from

Fernando Noboru Nishigima; Rolf Roland Weber; Márcia Caruso B??cego

2001-01-01

247

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

PubMed Central

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

Pratt, M. Margaret; John, Kaarthik; MacLean, Allan B.; Afework, Senait; Phillips, David H.; Poirier, Miriam C.

2011-01-01

248

Atmospheric concentrations of polycyclic aromatic hydrocarbons during chimney sweeping.  

PubMed Central

Air sampled from the breathing zone of chimney sweeps during "dirty work" and soot samples were analysed for polycyclic aromatic hydrocarbons (PAH). A total of 20 PAH were quantified by gas chromatography-mass spectrometry in 115 air samples and 18 soot samples. These included benzo(b)fluoranthene, benzo(a)pyrene (BaP), chrysene, dibenz(a,h)anthracene, and indeno (1,2,3-cd)pyrene, all of which are animal carcinogens. The summed atmospheric concentration of these compounds depended on the type of fuel used and averaged 2.27 micrograms/m3 for oil fuel. If a mixture of oil and solid fuel was used the concentration was 5.06 micrograms/m3; pure solid fuel heating yielded 5.08 micrograms/m3. The air concentrations of BaP were 0.36, 0.83, and 0.82 micrograms/m3 respectively. The soot samples recovered after using the three different fuel types were 10.50, 109.10, and 51.25 mg BaP/kg. The maximum total concentrations of the five carcinogenic PAH were 243.70, 691.06, and 213.94 mg/kg respectively. The time weighted, shift mean concentrations of 0.02 to 0.21 micrograms/m3 benzo(a)pyrene obtained on 11 days form the basis for the industrial medical estimation of risk.

Knecht, U; Bolm-Audorff, U; Woitowitz, H J

1989-01-01

249

DUSTY WINDS: EXTRAPLANAR POLYCYCLIC AROMATIC HYDROCARBON FEATURES OF NEARBY GALAXIES  

SciTech Connect

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

McCormick, Alexander; Veilleux, Sylvain [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Rupke, David S. N., E-mail: alexm@astro.umd.edu, E-mail: veilleux@astro.umd.edu, E-mail: rupked@rhodes.edu [Rhodes College, 2000 North Parkway, Memphis, TN 38112 (United States)

2013-09-10

250

Aromatized arborane/fernane hydrocarbons as biomarkers for cordaites  

NASA Astrophysics Data System (ADS)

Previous palaeobotanical and palynological studies on coals from Euramerican Pennsylvanian (? Late Carboniferous) coal basins indicate a major change in coal-swamp floras, especially at the Westphalian Stephanian (?Kasimovian Gzhelian, according to Geological Time Scale 2004) boundary. A flora dominated by arborescent lycophytes was replaced by a vegetation dominated by marattialean tree ferns in various Euramerican coal basins. Earlier combined palynological and organic geochemical studies on Westphalian/Stephanian coals and shales from the Saar-Nahe Basin (Germany) revealed that the distribution of aromatized arborane/fernane hydrocarbons in solvent extracts reflects the increasing importance of seed plants, especially cordaites (extinct group of gymnosperms), conifers and pteridosperms. However, the biological source of the precursor molecules could not be specified. To clarify if the arborane/fernane derivatives MATH, MAPH, DAPH 1, and DAPH 2 in Westphalian/Stephanian coals can be assigned to one of the three potential source plant groups, we analyzed coals, sediments and fossil plant remains from different Euramerican locations with respect to their biomarker composition and stable carbon isotopic composition. Thereby, stable carbon isotopic ratios showed only insignificant variations between Westphalian and Stephanian samples and proved to be an unsuitable tool to describe floral changes during the Westphalian/Stephanian of the Saar-Nahe Basin. In contrast, we were able to show for the first time that MATH, MAPH, DAPH 1 and DAPH 2 are prominent constituents only in extracts of cordaitean macrofossils and can therefore be regarded as biomarkers for this group of gymnosperms.

Auras, Stefan; Wilde, Volker; Scheffler, Kay; Hoernes, Stephan; Kerp, Hans; Püttmann, Wilhelm

2006-12-01

251

Occupational exposure to Polycyclic Aromatic Hydrocarbons in wood dust  

NASA Astrophysics Data System (ADS)

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

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

2009-02-01

252

Novel isoxazole polycyclic aromatic hydrocarbons as DNA-intercalating agents.  

PubMed

The third generation of isoxazole polycyclic aromatic hydrocarbons, acting as DNA-intercalator agents and possessing the binding constants in the range 10(4)-10(5) M(-1), in order to easily diffuse targeting remotely implanted tumors, has been synthesized in good yields according to the 1,3-dipolar cycloaddition methodology. The structure of the obtained cycloadducts has been determined by NOE experiments and supported by computational studies at PM3 level. All the obtained compounds have been tested for their in vitro cytotoxic activity and the most potent of them, (3RS,5SR)-2-benzyl-N,N-dimethyl-3-(pyren-1-yl)isoxazolidine-5-carboxamide (7d), showed an IC(50) of 4 ?M upon the human lung cancer (A-549) cells. Moreover, compound 7d showed binding constant for the intercalation with calf thymus DNA, poly-d(AT)(2) and poly-d(GC)(2) of 1.7 × 10(5) M(-1), 1.6 × 10(5) M(-1) and 0.3 × 10(5) M(-1), respectively. Biological and docking studies showed that, in vitro, these compounds complex by intercalation between base pairs, approaching the DNA from its minor groove with a preference for the AT nucleobases pairs. PMID:22405647

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

2012-05-01

253

Oxidation of polynuclear aromatic hydrocarbons in water. 1: Ozonation  

SciTech Connect

The oxidation of three polynuclear aromatic hydrocarbons (PAHs), fluorene, phenanthrene, and acenaphthene, in aqueous solution with ozone has been studied. The influence of hydroxyl radical inhibitors, pH, ozone partial pressure, and temperature was investigated. All the PAHs studied show high oxidation rates with ozone. The ozonation of fluorene seems to be due to both direct and hydroxyl radical reactions while for the rest of the PAHs the ozonation develops only through direct reactions with ozone. Rate constants for the direct reaction between these PAHs and ozone have also been calculated. The reactivity with ozone goes in the following order: fluorene < phenanthrene < acenaphthene. The contribution of radical reactions represents more than 90% in the ozonation of fluorene in most cases except in the presence of hydroxyl radical inhibitors. In a standard agitated reactor the kinetic regime of the absorption of ozone corresponds to a slow reaction in the case of fluorene and phenanthrene and to a fast reaction in the case of acenaphthene.

Beltran, F.J.; Encinar, J.M.; Rivas, J. [Univ. de Extremadura, Badajoz (Spain). Dept. de Ingenieria Quimica y Energetica; Ovejero, G. [Univ. Complutense, Madrid (Spain). Dept. de Ingenieria Quimica

1995-05-01

254

Adsorption and absorption of polycyclic aromatic hydrocarbons to rice roots.  

PubMed

Rice roots and surrounding air, soil and water samples were collected for polycyclic aromatic hydrocarbon (PAH) analysis. The rice roots were separated into lateral roots and nodal roots, and the PAH concentration in the former was found to be higher than that in the latter. In addition, root physiological characteristics including root biotic mass, root lipid content and specific surface area are also discussed. When normalizing the total, adsorption and absorption PAH fractions on a dry root weight basis to root biomass, root lipid, and surface area bases respectively, the differences between PAHs in the two types of roots diminished by 2 to 3 times on average. Results from sequential extraction indicated that PAHs were more easily absorbed by interior rice roots than adsorbed on the surface. In addition, more than 60% of total PAHs accumulated in root tissue for both lateral and nodal roots. However, the results were highly related to the solvent used, extraction time and methodology. Correlation analysis between bioconcentration factors (root over environment) and K(OA), K(OW) showed water to be more significant for PAH adsorption in rice roots than other environmental media. PMID:17182157

Jiao, X C; Xu, F L; Dawson, R; Chen, S H; Tao, S

2007-07-01

255

Particle-bound polycyclic aromatic hydrocarbon concentrations in transportation microenvironments  

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

256

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

NASA Technical Reports Server (NTRS)

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

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

1993-01-01

257

FT-IR spectroscopic studies of polycyclic aromatic hydrocarbons  

NASA Technical Reports Server (NTRS)

Proper assessment of the hypothesis which correlates polycyclic aromatic hydrocarbons (PAHs) with the unidentified infrared emission bands requires additional experimental laboratory data. In order to address this need, thermal infrared emission studies were performed on a subset of PAHs suggested to be of astrophysical importance. It was proposed that infrared emission from interstellar PAHs occurs following absorption of an ultraviolet photon. Since energy transfer to the ground electronic state can be rapid for a species in which intersystem crossing is negligible, the emission spectrum may be viewed as resulting from an equilibrium vibrational temperature (Leger and d'Hendecourt, 1987). This has been the basis for using infrared absorption spectra to calculate the corresponding emission spectra at various temperatures. These calculations were made using room temperature infrared absorption coefficients instead of those at the temperature of interest because of the latter's unavailability. The present studies are designed to address the differences between the calculated and experimental thermal emission spectra and to provide information which will be useful in future ultraviolet induced infrared fluorescence studies. The emission spectra have been obtained for temperatures up to 825K using an emission cell designed to mount against an external port of an FT-IR spectrometer. These spectra provide information concerning relative band intensities and peak positions which is unavailable from previous calculations.

Salisbury, D. W.; Allen, J. E., Jr.; Donn, B.; Moore, W. J.; Khanna, R. K.

1990-01-01

258

Determination of polycyclic aromatic hydrocarbons in the lung.  

PubMed

Polycyclic aromatic hydrocarbons (PAHs) accumulated in human lung samples from men (n = 236) and women (n = 128) were determined by high-performance liquid chromatography (HPLC) to examine their association with lung cancer. The mean values for benzo[a]pyrene (BaP), benzo[k]fluoranthene (BkF), and benzo[g,h,i]perylene (BghiP) in lungs (ng/g dry lung) of Japanese autopsied patients were 0.54, 0.44, and 0.87, respectively. The modal values were 0.3, 0.3 and 0.5, respectively. Each of the PAH concentrations was highly correlated with the others (r > 0.83). PAH concentrations in the lungs showed age-related increases with low correlation-coefficient values. BaP, BkF and BghiP concentrations in lungs of various subgroups were in the following order: male > female; and lung cancer > all cancers > non-cancer among male not female group. Only BghiP concentration in the lungs of the male smoker group is significantly higher (P < 0.10) than that of the male non-smoker group. Even among non-smoker groups, PAH concentrations in the lungs of male group were significantly higher than those of female group. In the male population, excess exposure to PAHs together with fine carbon particles, such as tobacco smoke or diesel exhaust, correlated with increased prevalence of lung cancer. PMID:8507106

Seto, H; Ohkubo, T; Kanoh, T; Koike, M; Nakamura, K; Kawahara, Y

1993-05-01

259

Role of radical cations in aromatic hydrocarbon carcinogenesis  

SciTech Connect

Carcinogenic activation of polycyclic aromatic hydrocarbons (PAH) involves two main pathways: one-electron oxidation and monooxygenation. One-electron oxidation produces PAH radical cations, which can react with cellular nucleophiles. Results from biochemical and biological experiments indicate that only PAH with ionization potentials below ca. 7.35 eV can be metabolically activated by one-electron oxidation. In addition, the radical cations of carcinogenic PAH must have relatively high charge localization to react effectively with macromolecules in target cells. Metabolic formation of PAH quinones proceeds through radical cation intermediates. Binding of benzo(a)pyrene (BP) to mouse skin DNA occurs predominantly at C-6, the position of highest charge localization in the BP radical cation, and binding of 6-methylBP to DNA in mouse skin yields a major adduct with the 6-methyl group bound to the 2-amino group of deoxyguanosine. Studies of carcinogenicity by direct application of PAH to rat mammary gland indicate that only PAH with ionization potentials low enough for activation by one-electron oxidation produce tumors in this target tissue. These constitute some of the results which provide evidence for the involvement of one-electron oxidation in PAH carcinogenesis. 78 references.

Cavalieri, E.; Rogan, E.

1985-12-01

260

Infrared Spectroscopy of Matrix-Isolated Polycyclic Aromatic Hydrocarbon Cations  

NASA Technical Reports Server (NTRS)

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

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

1995-01-01

261

Depletion of gaseous polycyclic aromatic hydrocarbons by a forest canopy  

NASA Astrophysics Data System (ADS)

Rapid uptake of gaseous polycyclic aromatic hydrocarbons (PAHs) by a forest canopy was observed at Borden in Southern Ontario, Canada during bud break in early spring 2003. High volume air samples were taken on 12 individual days at three different heights (44.4, 29.1, and 16.7 m) on a scaffolding tower and on the forest floor below the canopy (1.5 m). Concentrations of PAHs were positively correlated to ambient temperature, resulting from relatively warm and polluted air masses passing over the Eastern United States and Toronto prior to arriving at the sampling site. An analysis of vertical profiles and gas/particle partitioning of the PAHs showed that gaseous PAHs established a concentration gradient with height, whereas levels of particulate PAHs were relatively uniform, implying that only the uptake of gaseous PAHs by the forest canopy was sufficiently rapid to be observed. Specifically, the gaseous concentrations of intermediate PAHs, such as phenanthrene, anthracene, and pyrene, during budburst and leaf emergence were reduced within and above the canopy. When a gradient was observed, the percentage of PAHs on particles increased at the elevations experiencing a decrease in gas phase concentrations. The uptake of intermediate PAHs by the canopy also led to significant differences in gaseous PAH composition with height. These results are the most direct evidence yet of the filter effect of forest canopies for gaseous PAHs in early spring. PAH deposition fluxes and dry gaseous deposition velocities to the forest canopy were estimated from the concentration gradients.

Choi, S.-D.; Li, H.; Su, Y.; Gevao, B.; Harner, T.; Staebler, R. M.; Wania, F.

2008-02-01

262

Depletion of gaseous polycyclic aromatic hydrocarbons by a forest canopy  

NASA Astrophysics Data System (ADS)

Rapid uptake of gaseous polycyclic aromatic hydrocarbons (PAHs) by a forest canopy was observed at Borden in Southern Ontario, Canada during bud break in early spring 2003. High volume air samples were taken on 12 individual days at three different heights (44.4, 29.1, and 16.7 m) on a scaffolding tower and on the forest floor below the canopy (1.5 m). Concentrations of PAHs were positively correlated to ambient temperature, resulting from relatively warm and polluted air masses passing over the Eastern United States and Toronto prior to arriving at the sampling site. An analysis of vertical profiles and gas/particle partitioning of the PAHs showed that gaseous PAHs established a concentration gradient with height, whereas levels of particulate PAHs were relatively uniform, implying that only the uptake of gaseous PAHs by the forest canopy was sufficiently rapid to be observed. Specifically, the gaseous concentrations of intermediate PAHs, such as phenanthrene, anthracene, and pyrene, during budburst and leaf emergence were reduced within and above the canopy. When a gradient was observed, the percentage of PAHs on particles increased at the elevations experiencing a decrease in gas phase concentrations. The uptake of intermediate PAHs by the canopy also led to significant differences in gaseous PAH composition with height. These results are the most direct evidence yet of the filter effect of forest canopies for gaseous PAHs in early spring. PAH deposition fluxes and dry gaseous deposition velocities to the forest canopy were estimated from the concentration gradients.

Choi, S.-D.; Staebler, R. M.; Li, H.; Su, Y.; Gevao, B.; Harner, T.; Wania, F.

2008-07-01

263

Fullerenes, fulleranes and polycyclic aromatic hydrocarbons in the Allende meteorite  

NASA Technical Reports Server (NTRS)

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).

Becker, L.; Bunch, T. E.

1997-01-01

264

Aromatic hydrocarbons emissions in diesel and biodiesel exhaust  

NASA Astrophysics Data System (ADS)

Regulated emissions of biodiesel blends are reasonably well documented in several works, non-regulated emissions, on the contrary, lack research. In this work, mono- and polycyclic aromatic hydrocarbons (MAHs and PAHs, respectively) emission tests were performed with a heavy-duty diesel engine, fueled with pure diesel (D) and biodiesel blends (v/v) of 2% (B2), 5% (B5) and 20% (B20%). The main objective of this study is to investigate the effect of the biodiesel addition on the emission profile of MAHs and PAHs. The tests were conducted using a six cylinder heavy-duty engine, typical of the Brazilian fleet of urban buses, in a steady-state condition under 1500 rpm. The PAHs were sampled with Teflon filters and XAD-2 cartridges and were identified by gaseous chromatograph coupled to a mass spectrometer (GC/MS) and quantified by flame ionization detection (GC/FID). The MAHs were sampled with active charcoal cartridges and analyzed by GC/FID. Both MAHs and PAHs filters and cartridges were extracted with dichloromethane in an ultrasonic bath. Ten PAHs and eight MAHs were identified and the average reduction of MAHs was 4.2% (B5), 8.2% (B5), and 21.1% (B20). The average reduction for PAHs was 2.7% (B2), 6.3% (B5), and 17.2% (B20). However, some PAHs and MAHs emissions increased because of/due to the biodiesel blends like phenanthrene, ethyl benzene, and trimethyl benzenes.

Corrêa, Sérgio Machado; Arbilla, Graciela

265

Polynuclear Aromatic Hydrocarbons Concentrations in Char-Broiled Meat Suya  

NASA Astrophysics Data System (ADS)

Polynuclear aromatic hydrocarbons (PNAs) concentrations in char-broiled meat suya have been determined in samples obtained from four different selling points in Warri Metropolis of Nigeria. The sixteen EPA priority PNAs were detected using Gas Chromatography and Flame Ionization Detector. Concentrations of total PNAs determined in the four sampling points were: EF1 (134.82< ±8.53 ?g kg-1), EF2 (113.83< ±7.93 ?g kg-1), WR3 (115.14< ±7.77 ?g kg-1), WR4 (81.95< ±6.76 ?g kg-1). Benzo(a)pyrene, which is often used as a reference indicator for PNAs carcinogenicity, was determined at levels above 5 ?g kg-1 recommended as maximum limit by Commission of European Communities for smoked meat and smoked meat products. It was however, observed that the 2-3 rings PNAs including naphthalene, fluorene, acenaphthylene, acenaphthene, phenanthrene and anthracene were more abundant owing to their high percentage composition in the matrix of the charbroiled meat. Although the levels observed for benzo(a)pyrene in the beef suya exceeded standard guidelines of European Commission, it may take the diet to consist of frequent consumption of barbecued meat before a significant contributions of PNAs contaminant to the human system can be thoroughly assessed.

Duke, Okoro; Albert, Ikolo O.

266

Engineered Antibodies for Monitoring of Polynuclear Aromatic Hydrocarbons  

SciTech Connect

Polynuclear aromatic hydrocarbons (PAHs) are a large class of structurally similar pollutants. Rapid, inexpensive, and high-throughput methods to identify and monitor PAHs are needed in several DOE focus areas, including human and ecosystem health effects, risk and exposure assessment, decontamination and decommissioning, and remediation. DOE has sponsored and participated in several demonstration projects in which commercial immunoassay kits proved useful and cost-effective for detection of PAHs and other pollutants. The emerging generation of sensors and residue recovery methods will require panels of antibodies with relatively subtle differences in cross-reactivity. This project is based on the premise that genetic engineering should be much more successful than conventional polyclonal and monoclonal antibody methods for developing these antibody panels. One objective of this project has been to define the structural basis and mechanisms by which antibodies bind and cross-react with various PAHs. A second objective has been to use this information to produce recombinant antibodies with improved performance in analytical procedures that DOE can use. A third objective has been development of PAH residue recovery and cleanup methods that will be compatible with immunoassays, and make instrumental analysis faster, more accurate, and less expensive.

Karu; Alexander E.; Roberts, Victoria A.; Li, Qing X.

2000-03-06

267

Magnetic Beads-based Bioelectrochemical Immunoassay of Polycyclic Aromatic Hydrocarbons  

SciTech Connect

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

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

2007-07-01

268

Detector for particulate polycyclic aromatic hydrocarbons in water.  

PubMed

It is estimated that most polycyclic aromatic hydrocarbons (PAHs) in environmental water are not dissolved but rather in particulate form. Nevertheless, the currently available optical detectors are not suited for proper sampling of solid PAHs. A new setup for direct sampling and quantification of suspended particulate PAHs in water is suggested. It is based on a polymeric film that has the capability of dissolving PAH particulates, coupled to a traditional laser-induced fluorescence probe. Kinetics and performance of two sampling modes have been studied: bulk sampling, by immersing the probe into the water, and surface sampling, by laying the film on the water surface. The latter method has proved to be more sensitive; however, it is diffusion-limited. Linear calibration plots have provided quantification over a wide concentration range with detection limits in the ppb range (these could be improved by using a modified probe). The effects due to other particulates in water have been studied and only little interferences have been observed. The possibility of analysis of PAH mixtures has been addressed and it has been concluded that multivariate analysis is needed. PMID:15789244

Levinson, Jane; Sluszny, Chanan; Yasman, Yakov; Bulatov, Valery; Schechter, Israel

2005-04-01

269

Cardiac Autonomic Dysfunction from Occupational Exposure to Polycyclic Aromatic Hydrocarbons  

PubMed Central

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

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

2013-01-01

270

Polycyclic Aromatic Hydrocarbon Ionization Energy Lowering in Water Ices  

NASA Technical Reports Server (NTRS)

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

Gudipati, Murthy S.; Allamandola, Louis J.

2004-01-01

271

Polycyclic aromatic hydrocarbons in frying oils and snacks.  

PubMed

The high incidence of lung cancer observed among Chinese women has been associated with exposure to fumes from cooking oil. Polycyclic aromatic hydrocarbons (PAHs) are a class of potentially mutagenic substances emitted from cooking oils heated at high temperatures. The objective of this study was to investigate whether deep frying with different oils under different conditions leads to the development of PAHs either in the oil or in the fried product (snacks). PAH analysis was carried out with solid-phase extraction followed by reverse-phase high-performance liquid chromatography and spectrofluorometric detection. Different oils were used to fry chips and extruded snacks in different industrial plants (continuous frying) at temperatures between 170 and 205 degrees C, and peanut oil was used to fry French fries and fish (discontinuous frying) at temperatures between 160 and 185 degrees C. No appreciable differences in PAH load was observed in the same oil before and after frying. Both before and after frying, the benzo[a]pyrene concentration in oils ranged from trace to 0.7 ppb. All the analyzed samples, including oils from fried snacks, had benzo[a]pyrene concentrations well below the 2 ppb limit recently proposed by the European Community. PMID:16416919

Purcaro, Giorgia; Navas, José A; Guardiola, Francesc; Conte, Lanfranco S; Moret, Sabrina

2006-01-01

272

Accumulation of mutagenic polycyclic aromatic hydrocarbons in biological sludge  

SciTech Connect

Research was conducted to study the lipophilic accumulation of mutagenic polycyclic aromatic hydrocarbons (PAH) in biological sludge produced during activated sludge treatment of fixed-bed coal-gasification wastewater. The activated sludge system was viewed as a two phase chemical system to model the PAH accumulation process, and PAH distribution in this system was quantified by an equilibrium distribution coefficient. A general equation was next developed from thermodynamic principles to predict a sludge lipid-gasifier wastewater distribution coefficient for any PAH of interest. Determination of the required parameters for this equation involved the use of a modified version of the UNIFAC method for calculating activity coefficients. PAH absorption isotherms for biological sludge in gasifier wastewater were determined by running a series of equilibrium absorption experiments. The results of these experiments indicated that the predictive equation accurately estimated distribution coefficients for most of the PAH tested. A bench scale activated sludge system treating gasifier wastewater was then operated to gather further data on PAH absorption.

Moretti, C.J.

1984-01-01

273

Distribution of polycyclic aromatic hydrocarbons in lime spray dryer ash  

SciTech Connect

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.

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

274

Polycyclic aromatic hydrocarbons and the diffuse interstellar bands: a survey.  

PubMed

We discuss the proposal relating the origin of some of the diffuse interstellar bands (DIBs) to neutral and ionized polycyclic aromatic hydrocarbons (PAHs) present in interstellar clouds. Laboratory spectra of several PAHs, isolated at low temperature in inert gas matrices, are compared with the spectra of five reddened early-type stars selected from an extensive set of astronomical spectra. From this comparison, it is concluded that PAH ions are good candidates to explain some of the DIBS. Unambiguous assignments are difficult, however, because of the shift in wavelengths and the band broadening induced in the laboratory spectra by the solid matrix. This situation is illustrated by a comparison with the gas-phase spectra made available recently for two PAH ions. Definitive band assignments and, ultimately, the test of the proposal that PAH ions carry some of the DIBs must await the availability of a larger set of gas-phase measurements in the laboratory. The present assessment offers a guideline for future laboratory experiments by allowing the preselection of promising PAH molecules to be studied in jet expansions. PMID:11543306

Salama, F; Galazutdinov, G A; Krelowski, J; Allamandola, L J; Musaev, F A

1999-11-20

275

Polycyclic aromatic hydrocarbon (PAH) ecotoxicology in marine ecosystems.  

PubMed

Low levels of oil and hence polycyclic aromatic hydrocarbons (PAHs) are naturally present in the marine environment, although levels have increased significantly following human extraction and use of oil and gas. Other major anthropogenic sources of PAHs include smelters, the use of fossil fuels in general, and various methods of waste disposal, especially incineration. There are two major sources for PAHs to marine ecosystems in Norway: the inshore smelter industry, and offshore oil and gas production activities. A distinction is generally made between petrogenic (oil-derived) and pyrogenic (combustion-derived) PAHs. Although petrogenic PAHs appear to be bioavailable to a large extent, pyrogenic PAHs are often associated with soot particles and less available for uptake into organisms. There is extensive evidence linking sediment-associated PAHs to induction of phase-I enzymes, development of DNA adducts, and eventually neoplastic lesions in fish. Most studies have focused on high-molecular-weight, carcinogenic PAHs such as benzo[a]pyrene. It is less clear how two- and three-ring PAHs affect fish, and there is even experimental evidence to indicate that these chemicals may inhibit some components of the phase I system rather than produce induction. There is a need for increased research efforts to clarify biological effects of two- and three-ring PAHs, PAH mixtures, and adaptation processes in marine ecosystems. PMID:16291565

Hylland, Ketil

2006-01-01

276

Polycyclic aromatic hydrocarbon (PAH) emissions from charcoal grilling  

NASA Astrophysics Data System (ADS)

The emission of polycyclic aromatic hydrocarbons (PAH) was quantitated in the smoke from the grilling of meat using hardwood charcoal as fuel in a table grill set. Smoke samples were collected with an ice-cooled condenser and subsequently cleaned up employing both open column- and high performance-liquid chromatography techniques. Using a PAH standard mixture, 23 PAH were identified in the smoke using gas chromatography-mass spectrometry. Emission levels of PAH ranged from several tens of ?g kg -1 meat for some 3- and 4-ringed PAH, to sub ?g kg -1 meat levels for the 5- and 6-ringed PAH (sum of PAH approximately 0.1 mg kg -1 meat), originating from a 10 min grilling of 0.33 kg minced lean pork. The major source of PAH emitted to the local air environment from charcoal grilling is from the combustion of the charcoal itself. The amount of PAH emitted from charcoal grilling in Sweden, time period June to August, is estimated to approximately 2 kg which is a minor source to the total emissions of PAH to the environment. However, relatively large peak exposures of PAH can be expected in a more local environment, e.g. during household grilling.

Dyremark, Anders; Westerholm, Roger; Övervik, Eva; Gustavsson, Jan-Åke

277

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

PubMed

Occupational exposures to wood dust have been associated with an elevated risk of sinonasal cancer (SNC). Wood dust is recognized as a human carcinogen but the specific cancer causative agent remains unknown. One possible explanation is a co-exposure to; wood dust and polycyclic aromatic hydrocarbons (PAHs). PAHs could be generated during incomplete combustion of wood due to heat created by use of power tools. To determine if PAHs are generated from wood during common wood working operations, PAH concentrations in wood dust samples collected in an experimental chamber operated under controlled conditions were analyzed. In addition, personal air samples from workers exposed to wood dust (n = 30) were collected. Wood dust was generated using three different power tools: vibrating sander, belt sander, and saw; and six wood materials: fir, Medium Density Fiberboard (MDF), beech, mahogany, oak and wood melamine. Monitoring of wood workers was carried out by means of personal sampler device during wood working operations. We measured 21 PAH concentrations in wood dust samples by capillary gas chromatography-ion trap mass spectrometry (GC-MS). Total PAH concentrations in wood dust varied greatly (0.24-7.95 ppm) with the lowest being in MDF dust and the highest in wood melamine dust. Personal PAH exposures were between 37.5-119.8 ng m(-3) during wood working operations. Our results suggest that PAH exposures are present during woodworking operations and hence could play a role in the mechanism of cancer induction related to wood dust exposure. PMID:23087908

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

2012-01-01

278

Bioavailability of polycyclic aromatic hydrocarbons in the North Sea  

SciTech Connect

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

Utvik, T.I.R. (Norsk Hydro E and P Operations, Bergen (Norway). Environmental Section); Johnsen, S. (Statoil R and D Centre, Trondheim (Norway))

1999-06-15

279

Method of upgrading oils containing hydroxyaromatic hydrocarbon compounds to highly aromatic gasoline  

DOEpatents

The present invention is a multi-stepped method of converting an oil which is produced by various biomass and coal conversion processes and contains primarily single and multiple ring hydroxyaromatic hydrocarbon compounds to highly aromatic gasoline. The single and multiple ring hydroxyaromatic hydrocarbon compounds in a raw oil material are first deoxygenated to produce a deoxygenated oil material containing single and multiple ring aromatic compounds. Then, water is removed from the deoxygenated oil material. The next step is distillation to remove the single ring aromatic compouns as gasoline. In the third step, the multiple ring aromatics remaining in the deoxygenated oil material are cracked in the presence of hydrogen to produce a cracked oil material containing single ring aromatic compounds. Finally, the cracked oil material is then distilled to remove the single ring aromatics as gasoline.

Baker, Eddie G. (Richland, WA); Elliott, Douglas C. (Richland, WA)

1993-01-01

280

Source identification of aromatic hydrocarbons in sediments using GC\\/MS  

Microsoft Academic Search

A method that may distinguish between input of polycyclic aromatic hydrocarbons (PAH) from petroleum and combustion sources is demonstrated on sediment samples. Selected series of aromatics (unsubstituted compounds and their Câ-Câ alkyl homologues) are quantified by computerized GC\\/MS. The alkyl homologue distribution (AHD) within each series and the sum of components in each series relative to the sum of all

S. Sporstoel; Nina Gjos; Rainer G. Lichtenthaler; Kay O. Gustavsen; Kjell Urdal; Froydis Oreld; J. Skel

1983-01-01

281

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

Microsoft Academic Search

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

ANIL K. GOYAL; G. J. Zylstra

1996-01-01

282

Biodegradation of High-Molecular-Weight Polycyclic Aromatic Hydrocarbons by Bacteria  

Microsoft Academic Search

Interest in the biodegradation mechanisms and environ- mental fate of polycyclic aromatic hydrocarbons (PAHs) is prompted by their ubiquitous distribution and their potentially deleterious effects on human health. PAHs constitute a large and diverse class of organic compounds and are generally de- scribed as molecules which consist of three or more fused aromatic rings in various structural configurations (5). The

ROBERT A. KANALY; SHIGEAKI HARAYAMA

2000-01-01

283

Polycyclic aromatic hydrocarbons in the environment: homologous series in soils and recent marine sediments  

Microsoft Academic Search

Soils and recent marine sediments contain a complex polycyclic aromatic hydrocarbon assemblage. The many series of alkylhomologs have a similar molecular weight distribution, and it varies little over a wide range of depositional environments. It is suggested that these hydrocarbons are formed in natural fires, are dispersed and mixed by air transport and eventually deposited into surface sediments. The analytical,

W. W. Youngblood; M. Blumer

1975-01-01

284

Chlorinated and polycyclic aromatic hydrocarbons in riverine and estuarine sediments from Pearl River Delta, China  

Microsoft Academic Search

Spatial distribution of chlorinated hydrocarbons [chlorinated pesticides (CPs) and polychlorinated biphenyls (PCBs)] and polycyclic aromatic hydrocarbons (PAHs) was measured in riverine and estuarine sediment samples from Pearl River Delta, China, collected in 1997. Concentrations of CPs of the riverine sediment samples range from 12 to 158 ng\\/g, dry weight, while those of PCBs range from 11 to 486 ng\\/g. The

Bi-Xian Mai; Jia-Mo Fu; Guo-Ying Sheng; Yue-Hui Kang; Zheng Lin; Gan Zhang; Yu-Shuan Min; Eddy Y. Zeng

2002-01-01

285

Atmospheric concentrations of saturated and aromatic hydrocarbons around a Greek oil refinery  

Microsoft Academic Search

Petroleum refineries are large industrial installations that are responsible for the emission of several pollutants into the atmosphere. Hydrocarbons are among the most important air pollutants that are emitted by petroleum refineries, since they are involved in almost every refinery process. The ambient air concentrations of many saturated and aromatic hydrocarbons were measured in several sites around an oil refinery,

P. D. Kalabokas; J. Hatzianestis; J. G. Bartzis; P. Papagiannakopoulos

2001-01-01

286

Influence of humic substances on the formation of chlorinated polycyclic aromatic hydrocarbons during chlorination of polycyclic aromatic hydrocarbon polluted water  

SciTech Connect

Chlorinated polycyclic aromatic hydrocarbons (PAH) are present at nanogram per liter levels in lake water. Some of these compounds are known to be mutagenic in the Ames Salmonella test. The PAH compounds fluorene, anthracene, fluoranthene, and benzo(a)pyrene were dissolved in lake water with low humus content and in humus water with 9.17 mg of total organic carbon/L, followed by sodium hypochlorite chlorination at different concentrations. Reaction of PAH and formation of chlorinated PAH were measured by cyclohexane extraction of the samples 3 days after chlorination and gas chromatography/mass spectrometry analyses of the extracts. The PAH-chlorine reaction was found to be dependent upon the concentration of free active chlorine in the water, and the presence of humic substances was found to affect the formation of chlorinated PAH. Chlorinated PAH were formed in the lake water samples of fluoranthene and benzo(a)pyrene, but no chlorinated PAH were detected in the presence of humic substances.

Johnsen, S.; Gribbestad, I.S.

1988-08-01

287

Vapor pressures and enthalpies of sublimation of polycyclic aromatic hydrocarbons and their derivatives  

SciTech Connect

The vapor pressures of a series of polycyclic aromatic hydrocarbons (PAH) and heteroatom-containing PAH have been measured using the Knudsen effusion technique. Aromatic hydrocarbons examined included anthracene, phenanthrene, pyrene, 2,3-benzofluorene, naphthacene, perylene, pentacene, and coronene. Heteroatomic aromatic species examined included phenanthridine, perinaphthenone, 3-hydroxy-1-phenalen-1-one, benz[g]isoquinoline-5,10-dione, 1,2-benzodiphenylene sulfide, 1-hydroxypyrene, and 6,11-dihydroxy-5,12-naphthacenedione. The measurements were all made in the solid sublimation regime, and enthalpies of sublimation were calculated from the Clausius-Clapeyron equation.

Oja, V.; Suuberg, E.M. [Brown Univ., Providence, RI (United States). Div. of Engineering] [Brown Univ., Providence, RI (United States). Div. of Engineering

1998-05-01

288

Aromatic hydrocarbon optrodes for groundwater monitoring applications. Final report, September 1988-February 1990  

SciTech Connect

Research documented in this report produced a fiber-optic sensor utilizing a porous optical waveguide. This offered the advantage of improved sensitivity and specificity by impregnating fiber with a chemical indicator whose optical transmission properties change in the presence of aromatic species. The concept was adequately demonstrated the laboratory and a prototype optrode was developed which was sensitive for aromatic hydrocarbons to 50 ppb. The basic concept was proven. Fiber-optic sensor, Groundwater monitoring, Aromatic hydrocarbon optrodes, Porous glass xylene sensor, Chemical sensors, Evanescent fiber-optic sensor.

Tabacco, M.B.

1993-12-01

289

Real-time monitoring of polycyclic aromatic hydrocarbons and respirable suspended particles from environmental tobacco smoke in a home  

SciTech Connect

Real-time measurement of polycyclic aromatic hydrocarbons (PAH) on fine particles was evaluated in a home with environmental tobacco smoke (ETS) as a source. Respirable suspended particles (RSP) were also monitored. Comparison of PAH and RSP concentrations from these experiments suggests: (1) the PAH concentrations for the two types of cigarettes--a regular Marlboro filter cigarette and a University of Kentucky reference cigarette No. 2R1--were similar, but the RSP concentrations were different; (2) concentrations from the real-time PAH monitor were linearly related to RSP concentrations; (3) the slopes of the regression lines between PAH and RSP differed for the two types of cigarettes. The real-time PAH monitor appears to be a useful tool for evaluating mathematical models to predict the concentration time series in indoor microenvironments.

Ott, W.; Wilson, N.K.; Klepeis, N.; Switzer, P.

1994-01-01

290

Uptake, metabolism and discharge of polycyclic aromatic hydrocarbons by marine fish  

Microsoft Academic Search

The uptake, metabolism and discharge of two polycyclic aromatic hydrocarbons, 14C-naphthalene and 3H-3,4-benzopyrene, were studied in 3 species of marine fish (mudsucker or sand goby, Gillichthys mirabilis; sculpin, Oligocottus maculosus; sand dab, Citharichthys stigmaeus). The path of hydrocarbons through the fish included entrance through the gills, metabolism by the liver, transfer of hydrocarbons and their metabolites to the bile, and,

R. F. Lee; R. Sauerheber; G. H. Dobbs

1972-01-01

291

Fluorescence Spectroscopy of Gas-phase Polycyclic Aromatic Hydrocarbons  

NASA Astrophysics Data System (ADS)

The purpose of this investigation was to produce fluorescence spectra of polycyclic aromatic hydrocarbon (PAH) molecules in the gas-phase for comparison with blue luminescence (BL) emission observed in astrophysical sources te{ref2,ref3,ref4}. The BL occurs roughly from 350 to 450 nm, with a sharp peak near 380 nm. PAHs with three to four rings, e.g. anthracene and pyrene, were found to produce luminescence in the appropriate spectral region, based on existing studies. Relatively few studies of the gas-phase fluorescence of PAHs exist; those that do exist have dealt primarily with the same samples commonly available for purchase such as pyrene and anthracene. In an attempt to understand the chemistry of the nebular environment we also obtained several nitrogen substituted PAHs from our colleagues at NASA Ames. In order to simulate the astrophysical environment we also took spectra by heating the PAHs in a flame. The flame environment counteracts the formation of eximers and permits the spectroscopy of free-flying neutral molecules. Experiments with coal tar demonstrate that fluorescence spectroscopy reveals primarily the presence of the smallest molecules, which are most abundant and which possess the highest fluorescence efficiencies. One gas-phase PAH that seems to fit the BL spectrum most closely is phenanthridine. In view of the results from the spectroscopy of coal tar, a compound containing a mixture of PAHs ranging from small to very large PAH molecules, we can not preclude the presence of larger PAHs in interstellar sources exhibiting BL.

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

292

STRONG POLYCYCLIC AROMATIC HYDROCARBON EMISSION FROM z {approx} 2 ULIRGs  

SciTech Connect

Using the Infrared Spectrograph on board the Spitzer Space Telescope, we present low-resolution (64 < {lambda}/{delta}{lambda} < 124), mid-infrared (20-38 {mu}m) spectra of 23 high-redshift ULIRGs detected in the Booetes field of the NOAO Deep Wide-Field Survey. All of the sources were selected to have (1) f {sub {nu}}(24 {mu}m)>0.5 mJy; (2) R - [24]>14 Vega mag; and (3) a prominent rest frame 1.6 {mu}m stellar photospheric feature redshifted into Spitzer's 3-8 {mu}m IRAC bands. Of these, 20 show emission from polycyclic aromatic hydrocarbons (PAHs), usually interpreted as signatures of star formation. The PAH features indicate redshifts in the range 1.5 < z < 3.0, with a mean of (z) = 1.96 and a dispersion of 0.30. Based on local templates, these sources have extremely large infrared luminosities, comparable to that of submillimeter galaxies. Our results confirm previous indications that the rest-frame 1.6 {mu}m stellar bump can be efficiently used to select highly obscured star-forming galaxies at z {approx} 2, and that the fraction of starburst-dominated ULIRGs increases to faint 24 {mu}m flux densities. Using local templates, we find that the observed narrow redshift distribution is due to the fact that the 24 {mu}m detectability of PAH-rich sources peaks sharply at z = 1.9. We can analogously use observed spectral energy distributions to explain the broader redshift distribution of Spitzer-detected ULIRGs that are dominated by an active galactic nucleus (AGN). Finally, we conclude that z {approx} 2 sources with a detectable 1.6 {mu}m stellar opacity feature lack sufficient AGN emission to veil the 7.7 {mu}m PAH band.

Desai, Vandana; Soifer, B. T.; Melbourne, Jason [Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Dey, Arjun; Brand, Kate; Brodwin, Mark; Jannuzi, Buell T. [National Optical Astronomy Observatory, Tucson, AZ 85726-6732 (United States); Le Floc'h, Emeric [Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States); Armus, Lee; Teplitz, Harry [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); Brown, Michael J. I. [School of Physics, Monash University, Clayton, Victoria 3800 (Australia); Houck, James R.; Weedman, Daniel W. [Astronomy Department, Cornell University, Ithaca, NY 14853 (United States); Ashby, Matthew L. N.; Huang Jiasheng; Smith, Howard A.; Willner, Steve P. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Gonzalez, Anthony [Department of Astronomy, University of Florida, Gainesville, FL 32611-2055 (United States)

2009-08-01

293

Engineered antibodies for monitoring of polynuclear aromatic hydrocarbons  

SciTech Connect

'The long-term goal of this project is to develop antibodies and antibody-based methods for detection and recovery of polynuclear aromatic hydrocarbons (PAHs) and PAH adducts that are potential biomarkers in environmental and biological samples. The inherent cross-reactivity will be exploited by pattern recognition methods. Dr. Karu''s laboratory uses new haptens representing key PAHs to derive recombinant Fab (rFab) and single-chain Fv (scFv) antibodies from hybridoma lines and combinatorial phage display libraries. Computational models of the haptens and combining sites made by Dr. Roberts''s group are used to guide antibody engineering by mutagenesis. Dr. Li''s laboratory develops enzyme immunoassays (EIAs), sensors, and immunoaffinity methods that make use of the novel haptens and antibodies for practical analytical applications in support of DOE''s mission. This report summarizes work completed in one and one-half years of a 3-year project, with close collaboration between the three research groups. Dr. Alexander Karu''s laboratory: the authors proceeded with the two strategies described in the original proposal. Site-directed mutagenesis was used to correct differences in the rFab N-terminal amino acids that were introduced by the degenerate PCR primers used for gene amplification. The binding constants of the rFabs with the corrected sequences will be compared with those of the parent MAbs, and should be very similar. The 4D5 and 10C10 heavy and light chain sequences are being moved to the pCOMB3H phagemid vector to facilitate selection of new engineered mutants.'

Karu, A.E. [Univ. of California, Berkeley, CA (US); Roberts, V.A. [Scripps Research Inst., La Jolla, CA (US); Li, Q.X. [Univ. of Hawaii, Honolulu, HI (US)

1998-06-01

294

Polycyclic Aromatic Hydrocarbons in Residential Dust: Sources of Variability  

PubMed Central

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

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

2013-01-01

295

Neurotoxicity of polycyclic aromatic hydrocarbons and simple chemical mixtures.  

PubMed

Polycyclic aromatic hydrocarbons (PAHs) are a major class of environmental pollutants. These chemicals are the products of incomplete combustion and are present in every compartment of the environment. While the carcinogenic potential of these chemicals has been investigated in numerous studies, very little is known about the potential of these chemicals to produce damage to neural cells. The objective of this study was to investigate the toxicity of several model PAHs and binary mixtures of these chemicals in neural cells. Chemicals tested included benzo[a]pyrene (BaP), chrysene, anthracene, and pentachlorophenol (PCP). Four end points, including amino acid incorporation, total protein, total cell count, and viable cells (trypan dye exclusion), were measured in SY5Y human neuroblastoma cells and C6 rat glioma cells. The most sensitive measure of PAH toxicity in neural cells was amino acid incorporation into proteins. BaP was the most toxic of all PAHs tested, and anthracene failed to produce a toxic response at any concentration tested. Without metabolic activation, BaP induced a significant cytotoxic response at a concentration of 30 microM. With activation (0.25% S9), BaP induced a response at concentration levels of 3 microM and 30 microM. Minimal toxicity was observed with chrysene at the highest concentration tested, and anthracene failed to produce a toxic response at any concentration tested. With mixtures of PAHs the majority of samples induced additive responses. The minimum concentration required to induce a significant response was reduced for the mixture of chrysene and BaP when compared to BaP alone. In addition, PCP appeared to increase the inhibition of acetylcholinesterase by mipafox. The data suggest that PAHs are capable of producing damage to neural cells only at concentrations that are near their solubility limits. PMID:12825237

Tang, Y; Donnelly, K C; Tiffany-Castiglioni, E; Mumtaz, M M

2003-05-23

296

Formation history of polycyclic aromatic hydrocarbons in galaxies  

NASA Astrophysics Data System (ADS)

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 time-scale. 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 on to 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 detection in low-metallicity galaxies and the metallicity dependence of the PAH abundance in high-metallicity galaxies. The strong metallicity dependence of PAH abundance appears as a result of the strong metallicity dependence of the dust mass increase by the accretion of metals on to dust grains, which are eventually shattered into PAHs. We conclude that the observational trend of the PAH abundance can be a natural consequence of shattering of carbonaceous grains being the source of PAHs. To establish our scenario of PAH formation, observational evidence of PAH formation by shattering would be crucial.

Seok, Ji Yeon; Hirashita, Hiroyuki; Asano, Ryosuke S.

2014-04-01

297

Degradation and transformation of polycyclic aromatic hydrocarbons in soil systems  

SciTech Connect

Biodegradation of fourteen polycyclic aromatic hydrocarbon (PAH) compounds in two soils was studied by measuring parent compound disappearance and volatilization emission losses of these compounds from soil samples. Degradation kinetic rates using a first-order model were calculated as half-lives. Mean degradation half-lives corrected for volatilization varied from two days for two-ring PHAs to 59 days for three-ring PHAs to more than 300 days for PHAs with more than three rings. Volatilization corrected degradation of two-and three-ring PAH compounds in soil samples poisoned by 2% HgCl/sub 2/ was small but significant (p < 0.05). No significant degradation from poisoned soil was found for the PAH compound with more than three rings. RITZE (the Enhanced Regulatory and Investigative Treatment Zone) model was used to evaluate the treatment and leaching potential of PAH compounds in soil systems. All 12 PAH compounds evaluated were significantly assimilated in the soil system and no significant leaching of these compounds to ground water was predicted. Transformation of 7,12-dimethylbenz(a)anthracene was studied in a nonacclimated sandy loam soil at low and neutral pH soil conditions. Soil extracts containing transformation products were separated into three fractions based on HPLC retention time (polarity). Highly polar transformation products of 7,12-dimethylbenz(a)anthracene demonstrated a negative mutagenic response with the Ames mutagenicity assay, strain TA-100, for both low and neutral pH soils. Moderate and low polar fractions, however, induced mutagenicity for both soil samples with mutagenic ratios similar to those of the parent compound. Mutagenic responses for the metabolites formed from low and neutral pH soil were not different. Similar microbial distributions in the two pH soils contributed to this result.

Park, K.

1987-01-01

298

Near Infrared Spectra of Large Polycyclic Aromatic Hydrocarbons.  

NASA Astrophysics Data System (ADS)

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)

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

299

Polycyclic aromatic hydrocarbons in mountain soils of the subtropical Atlantic.  

PubMed

Surface soil samples from various altitudes on Tenerife Island, ranging from sea level up to 3400 m above mean sea level, were analyzed to study the distribution of 26 polycyclic aromatic hydrocarbons (PAHs) in a remote subtropical area. The stable atmospheric conditions in this island define three vertically stratified layers: marine boundary, trade-wind inversion, and free troposphere. Total PAH concentrations, 1.9 to 6000 microg/kg dry wt., were high when compared with those in tropical areas and in a similar range to those in temperate areas. In the marine boundary layer, fluoranthene (Fla), pyrene (Pyr), benz [a]anthracene (BaA), and chrysene (C + T) were largely dominant. The predominance of Fla over Pyr may reflect photo-oxidative processes during atmospheric transport, although coal combustion inputs cannot be excluded. The PAHs found in higher concentration in the soils from the inversion layer were benzo[b + j]fluoranthene (BbjF) + benzo[k]fluoranthene (BkF) > benzo[e]pyrene (BeP) approximately indeno[1,2, 3-cd]pyrene (Ind) > benzo[a]pyrene (BaP) approximately benzo[ghi]perylene (Bghi) > coronene (Cor) approximately dibenz[a,h]anthracene (Dib), reflecting that high temperatures and insolation prevent the accumulation of PAHs more volatile than BbjF in significant amounts. These climatic conditions involve a process of standardization that prevents the identification of specific PAH sources such as traffic, forest fires, or industrial inputs. Only soils with high total organic carbon (TOC) (e.g., 10-30%) preserve the more volatile compounds such as phenanthrene (Phe), methylphenanthrenes (MPhe), dimethylphenanthrenes (DMPhe), and retene (Ret). However, no relation between PAHs and soil TOC and black carbon (BC) was found. The specific PAH distributions of the free tropospheric region suggest a direct input from pyrolytic processes related to the volcanic emission of gases in Teide. PMID:12809298

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

2003-01-01

300

Sorption characteristics of polycyclic aromatic hydrocarbons in aluminum smelter residues.  

PubMed

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. PMID:17438813

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

2007-04-01

301

Temperature-Dependent Chemical-Specific Emission Rates of Aromatics and Polyaromatic Hydrocarbons (PAHs) in Bitumen Fume  

Microsoft Academic Search

Chemical-specific emission rates for simple aromatic and polycyclic aromatic hydrocarbon compounds (PAHs) from bitumens during hot mix asphalt (HMA) production and placement activities were evaluated using a headspace gas chromatography method. Temperature-dependent headspace concentrations of the EPA listed aromatic and polycyclic aromatic compounds were measured in the laboratory using headspace gas chromatographs equipped with a variety of detectors. The methodology

Clifford R. Lange; Mary Stroup-Gardiner

2007-01-01

302

Nitrated polycyclic aromatic hydrocarbons and azaarenes induce cytochrome P4501A in a fish hepatoma cell line  

Microsoft Academic Search

Nitrated polycyclic aromatic hydrocarbons (NPAH) and N-heterocyclic aromatic hydrocarbons (azaarenes) are as ubiquitous in the environment as their parent polycyclic aromatic hydrocarbon (PAH) compounds, although concentrations are commonly lower. Some of the NPAH and azaarenes are carcinogenic in mammals. Little is known, however, about their carcinogenicity and cytochrome P4501A (CYP1A) induction potency in fish. In this study, CYP1A induction potencies,

K. Fent; D. K. J. Jung

2000-01-01

303

Atmospheric concentrations of saturated and aromatic hydrocarbons around a Greek oil refinery  

NASA Astrophysics Data System (ADS)

Petroleum refineries are large industrial installations that are responsible for the emission of several pollutants into the atmosphere. Hydrocarbons are among the most important air pollutants that are emitted by petroleum refineries, since they are involved in almost every refinery process. The ambient air concentrations of many saturated and aromatic hydrocarbons were measured in several sites around an oil refinery, near the city of Corinth in Greece, during 1997. At the same time several meteorological parameters were also recorded. The seasonal, diurnal and spatial variations of the ambient air concentrations of these hydrocarbons were investigated and analyzed. An estimation of the contribution of the refinery to the measured atmospheric levels of hydrocarbons was also performed. The ambient air mixing ratios of the saturated and aromatic hydrocarbons in a large area outside the refinery were generally low, in ppbv range, much lower than the ambient air quality standards or the ambient air concentrations in the two largest urban centers in Greece, Athens and Thessaloniki.

Kalabokas, P. D.; Hatzianestis, J.; Bartzis, J. G.; Papagiannakopoulos, P.

304

Potentiometric online detection of aromatic hydrocarbons in aqueous phase using carbon nanotube-based sensors.  

PubMed

Surfaces made of entangled networks of single-walled carbon nanotubes (SWCNTs) display a strong adsorption affinity for aromatic hydrocarbons. Adsorption of these compounds onto the walls of SWCNTs changes the electrical characteristics of the SWCNT-solution interface. Using these features, we have developed a potentiometric sensor to detect neutral aromatic species. Specifically, we can detect online aromatic hydrocarbons in industrial coolant water. Our chromatographic results confirm the adsorption of toluene onto the walls of carbon nanotubes, and our impedance spectroscopy data show the change in the double layer capacitance of the carbon nanotube-solution interface upon addition of toluene, thus confirming the proposed sensing mechanism. The sensor showed a toluene concentration dependent EMF response that follows the shape of an adsorption isotherm and displayed an immediate response to the presence of toluene with a detection limit of 2.1 ppm. The sensor does not respond to other nonaromatic hydrocarbons that may coexist with aromatic hydrocarbons in water. It shows a qualitative sensitivity and selectivity of 100% and 83%, respectively, which confirms its ability to detect aromatic hydrocarbons in aqueous solutions. The sensor showed an excellent ability to immediately detect the presence of toluene in actual coolant water. Its operational characteristics, including its fast response, low cost, portability, and easy use in online industrial applications, improve those of current chromatographic or spectroscopic techniques. PMID:20809625

Washe, Alemayehu P; Macho, Santiago; Crespo, Gastón A; Rius, F Xavier

2010-10-01

305

Chemical degradation of substituted aromatic hydrocarbon compounds in soil/sediment systems: Progress report  

SciTech Connect

This project addresses the fate of organic contaminants in soil and sediment systems. The project is directed towards understanding some of the chemical pathways by which energy-related organic compounds may be oxidized in soils and sediments as a result of redox reaction with oxide minerals. Chemical degradation pathways may be an important mechanism for remediation of contaminated soils/sediments in the absence of microbial degradation. This project complements another research investigation which is investigating microbial degradation of unsubstituted polycyclic aromatic hydrocarbon compounds in different redox environments. The project is studying the chemical reactions of nitrogen-containing aromatic hydrocarbons with iron and manganese oxides. These oxides are likely to be the most prevalent oxidizing agents in soils and sediments in the absence of molecular oxygen and microbial activity. Previous screening studies in this laboratory have shown that unsubstituted PAH (e.g, naphthalene) are non-reactive with respect to redox reactions with manganese oxide, while hydroxy- and nitrogen-substituted aromatic hydrocarbon compounds undergo redox reaction with manganese oxide. The laboratory work for the near future will focus on understanding the reaction mechanisms of nitrogen-substituted aromatic hydrocarbon compounds with manganese oxide. The results of the study are expected to be useful in helping to develop basic knowledge on the fate and transport of aromatic hydrocarbon contaminants in subsurface environments.

Shanmuganantha, S.; Luthy, R.G.

1987-05-01

306

Applications of electrochemically-modulated liquid chromatography (EMLC): Separations of aromatic amino acids and polycyclic aromatic hydrocarbons  

SciTech Connect

The research in this thesis explores the separation capabilities of a new technique termed electrochemically-modulated liquid chromatography (EMLC). The thesis begins with a general introduction section which provides a literature review of this technique as well as a brief background discussion of the two research projects in each of the next two chapters. The two papers which follow investigate the application of EMLC to the separation of a mixture of aromatic amino acids and of a mixture of polycyclic aromatic hydrocarbons (PAHs). The last section presents general conclusions and summarizes the thesis. References are compiled in the reference section of each chapter. The two papers have been removed for separate processing.

Deng, L.

1998-03-27

307

Biodegradation aspects of polycyclic aromatic hydrocarbons (PAHs): a review.  

PubMed

PAHs are aromatic hydrocarbons with two or more fused benzene rings with natural as well as anthropogenic sources. They are widely distributed environmental contaminants that have detrimental biological effects, toxicity, mutagenecity and carcinogenicity. Due to their ubiquitous occurrence, recalcitrance, bioaccumulation potential and carcinogenic activity, the PAHs have gathered significant environmental concern. Although PAH may undergo adsorption, volatilization, photolysis, and chemical degradation, microbial degradation is the major degradation process. PAH degradation depends on the environmental conditions, number and type of the microorganisms, nature and chemical structure of the chemical compound being degraded. They are biodegraded/biotransformed into less complex metabolites, and through mineralization into inorganic minerals, H(2)O, CO(2) (aerobic) or CH(4) (anaerobic) and rate of biodegradation depends on pH, temperature, oxygen, microbial population, degree of acclimation, accessibility of nutrients, chemical structure of the compound, cellular transport properties, and chemical partitioning in growth medium. A number of bacterial species are known to degrade PAHs and most of them are isolated from contaminated soil or sediments. Pseudomonas aeruginosa, Pseudomons fluoresens, Mycobacterium spp., Haemophilus spp., Rhodococcus spp., Paenibacillus spp. are some of the commonly studied PAH-degrading bacteria. Lignolytic fungi too have the property of PAH degradation. Phanerochaete chrysosporium, Bjerkandera adusta, and Pleurotus ostreatus are the common PAH-degrading fungi. Enzymes involved in the degradation of PAHs are oxygenase, dehydrogenase and lignolytic enzymes. Fungal lignolytic enzymes are lignin peroxidase, laccase, and manganese peroxidase. They are extracellular and catalyze radical formation by oxidation to destabilize bonds in a molecule. The biodegradation of PAHs has been observed under both aerobic and anaerobic conditions and the rate can be enhanced by physical/chemical pretreatment of contaminated soil. Addition of biosurfactant-producing bacteria and light oils can increase the bioavailability of PAHs and metabolic potential of the bacterial community. The supplementation of contaminated soils with compost materials can also enhance biodegradation without long-term accumulation of extractable polar and more available intermediates. Wetlands, too, have found an application in PAH removal from wastewater. The intensive biological activities in such an ecosystem lead to a high rate of autotrophic and heterotrophic processes. Aquatic weeds Typha spp. and Scirpus lacustris have been used in horizontal-vertical macrophyte based wetlands to treat PAHs. An integrated approach of physical, chemical, and biological degradation may be adopted to get synergistically enhanced removal rates and to treat/remediate the contaminated sites in an ecologically favorable process. PMID:19442441

Haritash, A K; Kaushik, C P

2009-09-30

308

The Origins of Polycyclic Aromatic Hydrocarbons: Are They Everywhere?  

NASA Technical Reports Server (NTRS)

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 interstellar PAHs in meteorites and interplanetary dust particles. This in conjunction with the recent suggestion that PAHs are abundant in Jupiter's atmosphere will make the point that "PAHs are Everywhere".

Allamandola, L. J.; Morrison, David (Technical Monitor)

1994-01-01

309

Exposure of firefighters to particulates and polycyclic aromatic hydrocarbons.  

PubMed

Firefighting continues to be among the most hazardous yet least studied occupations in terms of exposures and their relationship to occupational disease. Exposures are complex, involving mixtures of particles and chemicals such as polycyclic aromatic hydrocarbons (PAHs). Adverse health effects associated with these agents include elevated incidences of coronary heart disease and several cancers. PAHs have been detected at fire scenes, and in the firehouse rest area and kitchen, routinely adjoining the truck bay, and where firefighters spend a major part of each shift. An academic-community partnership was developed with the Cincinnati Fire Department with the goal of understanding active firefighters' airborne and dermal PAH exposure. PAHs were measured in air and particulates, and number and mass concentrations, respectively, of submicron (0.02-1 ?m) and PM2.5 (2.5 ?m diameter and less) particles during overhaul events in two firehouses and a University of Cincinnati administrative facility as a comparison location. During overhaul firefighters evaluate partially combusted materials for re-ignition after fire extinguishment and commonly remove Self-Contained Breathing Apparatus (SCBA). Face and neck wipes were also collected at a domestic fire scene. Overhaul air samples had higher mean concentrations of PM2.5 and submicron particles than those collected in the firehouse, principally in the truck bay and kitchen. Among the 17 PAHs analyzed, only naphthalene and acenaphthylene were generally detectable. Naphthalene was present in 7 out of 8 overhaul activities, in 2 out of 3 firehouse (kitchen and truck bay) samples, and in none collected from the control site. In firefighter face and neck wipes a greater number of PAHs were found, several of which have carcinogenic activity, such as benzofluoranthene, an agent also found in overhaul air samples. Although the concentration for naphthalene, and all other individual PAHs, was very low, the potential simultaneous exposure to multiple chemicals even in small quantities in combination with high ultrafine particle exposure deserves further study. It is recommended that personal respiratory and skin protection be worn throughout the overhaul process. PMID:24512044

Baxter, C Stuart; Hoffman, Joseph D; Knipp, Michael J; Reponen, Tiina; Haynes, Erin N

2014-07-01

310

Polycyclic aromatic hydrocarbons in US and Swedish smokeless tobacco products  

PubMed Central

Background Debate about the health implications of using smokeless tobacco products (STPs) has prompted considerable interest in characterising their levels of toxic and carcinogenic components. In the present study seventy smokeless tobacco products from the US and Sweden, categorized as chewing tobacco, dry and moist snuff, hard and soft pellets, plug, and loose and portion snus, were analysed for twenty one polycyclic aromatic hydrocarbons (PAHs). The tested brands represented 80-90% of the 2008 market share for the major STP categories in these two countries. Results There were significant differences in the total and individual PAH concentrations in the different styles of product. Substantially higher levels of total PAHs (10–60 fold) were found in moist and dry snuff and soft pellets than in the other smokeless tobacco styles. The individual PAH concentrations followed the same patterns as total PAHs except for naphthalene, for which the highest concentrations were found in snus and moist snuff. Good correlations were obtained between benzo[a]pyrene (B[a]P) and all the other PAHs except naphthalene, 1-methylnaphthalene and 2-methylnaphthalene, providing evidence for the first time that it can be used as a good marker for PAHs in STPs. Results were generally in good agreement with two previous studies of PAHs in STPs, except for naphthalene for which significantly lower concentrations were found than previously reported. Analysis of the ratios of different PAHs confirmed that the use of fire-cured tobaccos in the snuffs and soft pellet were the major source of PAHs in these product styles, and provided, for the first time, some indications as to the source of PAHs in the other STP styles, including petrogenic and other combustion sources. Conclusions This study confirms the presence of PAHs in STPs, and identifies substantial differences between the levels in different STP categories. Since previous studies of naphthalene concentrations in STPs differed so markedly from those found in this study, it is recommended that further work on PAH determination is undertaken to investigate the source of this discrepancy.

2013-01-01

311

Polycyclic aromatic hydrocarbons in the South American environment.  

PubMed

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 levels are rarely reported in the scientific literature for South American countries. Few data were available, even though many regulatory agencies perform routine analysis of hydrocarbons in waters. No information was found specifically related to PAH compounds, which could indicate generally low PAH levels in waters. Regional PAH information for sediments also indicates higher levels. Overall, as observed for water, sediment data indicate a complex situation in densely populated areas affected by urban-industrial inputs where high PAH levels are found. In contrast, in remote areas a typical profile of diagenetic PAHs dominates. Concentrations are greatly variable and are principally related to several highly contaminated sites in Argentina and Brazil (hot spots) with levels four to five orders of magnitude higher. Even though PAHs have carcinogenic properties, little attention has been paid to the analysis of aquatic organisms except in the case of bivalves. As observed for other environmental receptors, the regional data distribution is uneven and is heavily centered in coastal environments and in a few countries (Argentina, Brazil, Chile, and Peru). The most comprehensive PAH monitoring program in the South American coastal environment is the Mussel Watch. Baseline PAH concentrations range from 200 to 700 microg kg(-1) lipids in unpolluted sites; from 1,000 to 3,000 microg kg(-1) in moderately contaminated sites; and from 4,000 to 13,000 microg/kg lipids in the most affected bivalves that come from areas of Río de la Plata (Argentine side), Recife (Brazil), and Punta Arenas (Chile). Critical data gaps exist with respect to PAH analysis in biota, including humans, in foodstuffs, and subsequent effects. Considering the high levels reported in the air compartment, risk assessment procedures in highly populated areas need to be performed. Additionally, few countries within the region have information on PAH levels. In these countries, this type of analysis needs to be performed, and the laboratory capacity needs to be built to assure the accomplishment of these

Barra, Ricardo; Castillo, Caroline; Torres, Joao Paulo Machado

2007-01-01

312

Distribution of pesticides and polycyclic aromatic hydrocarbons in house dust as a function of particle size.  

PubMed

House dust is a repository for environmental pollutants that may accumulate indoors from both internal and external sources over long periods of time. Dust and tracked-in soil accumulate most efficiently in carpets, and the pollutants associated with dust and soil may present an exposure risk to infants and toddlers, who spend significant portions of their time in contact with or in close proximity to the floor and who engage in frequent mouthing activities. The availability of carpet dust for exposure by transfer to the skin or by suspension into the air depends on particle size. In this study, a large sample of residential house dust was obtained from a commercial cleaning service whose clients were homeowners residing in the Raleigh-Durham-Chapel Hill (Research Triangle) area of North Carolina. The composite dust was separated into seven size fractions ranging from < 4 to 500 microm in diameter, and each fraction was analyzed for 28 pesticides and 10 polycyclic aromatic hydrocarbons (PAHs). Over 20% of the fractionated dust sample consisted of particles < 25 microm in diameter. Fourteen pesticides and all 10 of the target PAHs were detected in one or more of the seven size-fractionated samples. Sample concentrations reported range from 0.02 to 22 microg/g; the synthetic pyrethroids cis- and trans-permethrin were the most abundant pesticide residue. The concentrations of nearly all of the target analytes increased gradually with decreasing particle size for the larger particles, then increased dramatically for the two smallest particle sizes (4-25 microm and < 4 microm). PMID:10464072

Lewis, R G; Fortune, C R; Willis, R D; Camann, D E; Antley, J T

1999-09-01

313

Predictors of personal polycyclic aromatic hydrocarbon exposures among pregnant minority women in New York City.  

PubMed Central

As part of a multiyear birth-cohort study examining the roles of pre- and postnatal environmental exposures on developmental deficits and asthma among children, we measured personal exposures to polycyclic aromatic hydrocarbons (PAHs) among 348 pregnant women in northern Manhattan and the South Bronx, New York. Nonsmoking African-American or Dominican women were identified and recruited into the study. During the third trimester of pregnancy, each subject wore a personal air monitor for 48 hr to determine exposure levels to nine PAH compounds. In this study, we examined levels of exposures to PAHs and tested for associations with potential predictor variables collected from questionnaires addressing socioeconomic factors and day-to-day activities during pregnancy as well as activities and environmental exposures during the 48-hr monitoring period. Reliable personal monitoring data for women who did not smoke during the monitoring period were available for 344 of 348 subjects. Mean PAH concentrations ranged from 0.06 ng/m3 for dibenz[a,h]anthracene to 4.1 ng/m3 for pyrene; mean benzo[a]pyrene concentration was 0.50 ng/m3. As found in previous studies, concentrations of most PAHs were higher in winter than in summer. Multiple linear regression analysis revealed associations between personal PAH exposures and several questionnaire variables, including time spent outdoors, residential heating, and indoor burning of incense. This is the largest study to date characterizing personal exposures to PAHs, a ubiquitous class of carcinogenic air contaminants in urban environments, and is unique in its focus on pregnant minority women.

Tonne, Cathryn C; Whyatt, Robin M; Camann, David E; Perera, Frederica P; Kinney, Patrick L

2004-01-01

314

Distribution of pesticides and polycyclic aromatic hydrocarbons in house dust as a function of particle size.  

PubMed Central

House dust is a repository for environmental pollutants that may accumulate indoors from both internal and external sources over long periods of time. Dust and tracked-in soil accumulate most efficiently in carpets, and the pollutants associated with dust and soil may present an exposure risk to infants and toddlers, who spend significant portions of their time in contact with or in close proximity to the floor and who engage in frequent mouthing activities. The availability of carpet dust for exposure by transfer to the skin or by suspension into the air depends on particle size. In this study, a large sample of residential house dust was obtained from a commercial cleaning service whose clients were homeowners residing in the Raleigh-Durham-Chapel Hill (Research Triangle) area of North Carolina. The composite dust was separated into seven size fractions ranging from < 4 to 500 microm in diameter, and each fraction was analyzed for 28 pesticides and 10 polycyclic aromatic hydrocarbons (PAHs). Over 20% of the fractionated dust sample consisted of particles < 25 microm in diameter. Fourteen pesticides and all 10 of the target PAHs were detected in one or more of the seven size-fractionated samples. Sample concentrations reported range from 0.02 to 22 microg/g; the synthetic pyrethroids cis- and trans-permethrin were the most abundant pesticide residue. The concentrations of nearly all of the target analytes increased gradually with decreasing particle size for the larger particles, then increased dramatically for the two smallest particle sizes (4-25 microm and < 4 microm). Images Figure 1 Figure 2 Figure 3 Figure 4

Lewis, R G; Fortune, C R; Willis, R D; Camann, D E; Antley, J T

1999-01-01

315

Risk assessment of inhalation exposure to Particulate Polycyclic Aromatic Hydrocarbons in school children  

NASA Astrophysics Data System (ADS)

Polycyclic aromatic hydrocarbons (PAHs) associated with the inhalable fraction of particulate matter were determined for one year (2009-10) at an urban site located in proximity of industrial and heavy traffic roads in Delhi, India. PM10 (aerodynamic diameter ?10 ?m) levels were ~11.6 times the World Health Organization standard. Vehicular (59.5%) and coal combustion (40.5%) sources accounted for the high levels of PAHs (range 38.1 ng m-3 - 217.3 ng m-3) with four and five ring PAHs having ~80 % contribution. Atmospheric distribution of total PAHs were heavily influenced (~75%) by the carcinogenic species and the B[a]P equivalent concentrations, through both TEF and MEF approach, exhibited highest exposure risks during winter. Extremely high daily inhalation exposure of PAHs was observed during winter (439.43 ng day-1) followed by monsoon (232.59 ng day-1) and summer (171.08 ng day-1). Daily inhalation exposure of PAHs to school children during a day exhibited the trend: school hours>commuting to school>resting period, in all the seasons. Vehicular source contributions to daily PAH levels were significantly correlated (r=0.94, p<0.001) with the daily inhalation exposure level of school children. It is important to note that health hazards posed by vehicular pollution are born disproportionately by children attending certain schools based on the location of the school. Interestingly, since India is a tropical country, most of the buildings are naturally ventilated and their air exchange rates are higher than heating, ventilation, and air conditioning (HVAC)-equipped buildings, resulting into a significant impact of outdoor air on indoor air quality. In the apparent absence of any indoor PAH sources, outdoor concentrations and in turn air exchange rates (that are specific for infiltration and natural ventilation pathways) play a key role in assessing PAH exposure. A conservative estimate of ~11 excess cancer cases in children during childhood and ~ 652 cases for a lifetime inhalation exposure of PAHs at the observed concentration have been calculated in Delhi.

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

2013-12-01

316

Analysis of Atmospheric Polycyclic Aromatic Hydrocarbons and Nitropolycyclic Aromatic Hydrocarbons in Gas\\/Particle Phases Separately Collected by a High-volume Air Sampler Equipped with a Column Packed with XAD-4 Resin  

Microsoft Academic Search

We developed a sampler for collecting atmospheric polycyclic aromatic hydrocarbons (PAHs) and nitropoly- cyclic aromatic hydrocarbons (NPAHs) by attaching a glass column packed with XAD-4 resin to the gas sampling port of a high-volume air sampler equipped with a filter. When the upper and bottom layers of the column were packed with 64 g and 32 g of XAD-4 resin,

Yuki Araki; Ning Tang; Michihiro Ohno; Takayuki Kameda; Akira Toriba; Kazuichi Hayakawaa

2009-01-01

317

Formation mechanism of polycyclic aromatic hydrocarbons beyond the second aromatic ring.  

PubMed

The formation mechanism of polycyclic aromatic hydrocarbons (PAH) with three fused aromatic rings starting from naphthalene has been studied using accurate ab initio G3(MP2,CC)//B3LYP/6-311G** calculations followed by the kinetic analysis of various reaction pathways and computations of relative product yields. The results reveal new insights into the classical hydrogen abstraction-C2H2 addition (HACA) scheme of PAH growth. The HACA mechanism has been shown to produce mostly cyclopentafused PAHs instead of PAHs with six-member rings only, in contrast to the generally accepted view on this mechanism. Considering naphthalene as the initial reactant, the HACA-type synthesis of higher PAHs with all six-member rings, anthracene and phenanthrene, accounts only for 3-6% of the total product yield at temperatures relevant to combustion (1000-2000 K), whereas cyclopentafused PAHs, including acenaphthalene (41-48%), 4-ethynylacenaphthalene (?14%), 3-ethynylacenaphthalene (?7.5%), 1-methylene-1H-cyclopenta[b]naphthalene (?6%), and 3-methylene-3H-cyclopenta[a]naphthalene (?5%), account for another ?75%. It has been shown that acetylene addition to the radical site adjacent to the bay region in naphthalene (as in 1-naphthyl radical) or other similar PAH with a bay region is highly unlikely to be followed by the addition of a second acetylene molecule; alternatively, the bay region closure with a buildup of a new five-member ring occurs. Acetylene addition to a nonbay carbon atom (as in 2-naphthyl radical) can be followed by the second acetylene addition only at T < 1000 K, producing anthracene and phenanthrene. However, at temperatures relevant to combustion, such pathways give negligible contributions to the total product yield, whereas the dominant reaction product, 2-ethynylnaphthalene, is formed by simple hydrogen atom elimination from the attached ethenyl group. An additional six-member ring buildup may occur only after intermolecular hydrogen abstraction from ethynyl-substituted PAH (2-ethynylnaphthalene), in particular, from the carbon atoms adjacent to the existing ethynyl (C2H) fragment, followed by C2H2 addition producing adducts with two ethynyl C2H and ethenyl C2H2 groups next to each other, which then undergo a fast six-member ring closure. Nevertheless, this process has been shown to be relatively minor (?25%), whereas the major process is a five-member ring closure involving the same C2H and C2H2 groups and leading to a cyclopentafused PAH molecule. Although the computed product yields show a good agreement with experimentally observed concentrations of acenaphthalene and anthracene in various aliphatic and aromatic flames, the yield of phenanthrene, which exhibits an order of magnitude higher concentration than anthracene both in combustion flames and environmental mixtures, via the considered pathways is significantly underpredicted. This result points at the possible existence of another mechanism responsible for the formation of phenanthrene and other all-six-member-ring PAHs. The overall kinetic scheme for the HACA buildup process leading to various three-ring PAHs (both with six-member rings only and cyclopentafused) from naphthalene, which can be included in flame kinetic models, has been constructed, with rate constants for all individual reaction steps provided. PMID:23672431

Kislov, V V; Sadovnikov, A I; Mebel, A M

2013-06-13

318

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

SciTech Connect

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

Goyal, A.K.; Zylstra, G.J. [Rutgers Univ., New Brunswick, NJ (United States)

1996-01-01

319

Genomic analysis of polycyclic aromatic hydrocarbon degradation in Mycobacterium vanbaalenii PYR-1  

Microsoft Academic Search

Mycobacterium vanbaalenii PYR-1 is well known for its ability to degrade a wide range of high-molecular-weight (HMW) polycyclic aromatic hydrocarbons\\u000a (PAHs). The genome of this bacterium has recently been sequenced, allowing us to gain insights into the molecular basis for\\u000a the degradation of PAHs. The 6.5 Mb genome of PYR-1 contains 194 chromosomally encoded genes likely associated with degradation\\u000a of aromatic

Seong-Jae Kim; Ohgew Kweon; Richard C. Jones; Ricky D. Edmondson; Carl E. Cerniglia

2008-01-01

320

Molecular characterization of dioxygenases from polycyclic aromatic hydrocarbon-degrading Mycobacterium spp  

Microsoft Academic Search

Polycyclic aromatic hydrocarbon (PAH)-degrading genes nidA and nidB that encode the ? and ? subunits of the aromatic ring-hydroxylating dioxygenase have been cloned and sequenced from Mycobacterium vanbaalenii PYR-1 [Khan et al., Appl. Environ Microbiol. 67 (2001) 3577–3585]. In this study, the presence of nidA and nidB in 12 other Mycobacterium or Rhodococcus strains was investigated. Initially, all strains were

Barbara Brezna; Ashraf A. Khan; Carl E. Cerniglia

2003-01-01

321

A novel integrative technique for locating and monitoring polynuclear aromatic hydrocarbon discharges to the aquatic environment  

SciTech Connect

A simple integrative technique for locating and monitoring polynuclear aromatic hydrogen discharges to aquatic environments is described. The technique involves anchoring artificial substrates cut from a commercial oil-adsorbant cloth (3M Co.) near suspected sources of contamination. Analytical methodology involves mild ethanolic extraction and liquid-liquid partitioning to isolate a polynuclear aromatic hydrocarbon containing fraction that is amenable to analysis by high-pressure liquid chromatography.

Black, J.J.; Hart, T.F. Jr.; Black, P.J.

1982-05-01

322

Indirect- and direct-acting mutagenicity of diesel, coal and wood burning-derived particulates and contribution of polycyclic aromatic hydrocarbons and nitropolycyclic aromatic hydrocarbons.  

PubMed

Particulates exhausted from two types of diesel engines (DEPs), burning-derived particulates from three types of coal (CBPs) and burning-derived particulates from three types of wood (WBPs) were separated into four fractions by silica-gel column chromatography using n-hexane, n-hexane-dichloromethane (3:1, v/v), dichloromethane and methanol, as the corresponding eluents. The indirect-acting mutagenicity of each fraction was assayed by the Ames test using the Salmonella typhimurium TA100 strain with S9 mix and the direct-acting mutagenicity was assayed using the S. typhimurium TA98 strain without S9 mix. The polycyclic aromatic hydrocarbons (PAHs) and nitropolycyclic aromatic hydrocarbons (NPAHs) of each fraction were determined by high-performance liquid chromatography (HPLC). Both direct- and indirect-acting of mutagenicities were the highest in samples of DEPs. The contributions of PAHs in samples of WBPs and NPAHs in DEPs were the largest, respectively. PMID:19896557

Yang, Xiao-Yang; Igarashi, Kazuhiko; Tang, Ning; Lin, Jin-Ming; Wang, Wei; Kameda, Takayuki; Toriba, Akira; Hayakawa, Kazuichi

2010-01-01

323

Biodegradation of volatile aromatic hydrocarbons by native soil and groundwater microorganisms: Microcosm studies  

SciTech Connect

The goal of this project was twofold: to develop and test strategies for enhancing the microbial degradation of hydrocarbon contaminants in subsurface soil and groundwater, and to understand why and under what conditions these strategies can be successful. The work deals primarily with what are generally considered the highest priority contaminants, from a toxicological point of view, in a typical hydrocarbon remediation site -- the aromatic fraction, including benzene and related compounds. The work involved the determination of the relative degradation rates of aromatic, as well as several nonaromatic constituents, in conjunction with an analysis of the effect of oxygen concentration and with an extensive microbiological characterization.

Rai, D.N.; Dasch, J.M.; Gibson, T.L.; Ang, C.C.; Abdul, A.S.

1994-05-01

324

Supercritical carbon dioxide extraction of polychlorinated biphenyls, polycyclic aromatic hydrocarbons, heteroatom-containing polycyclic aromatic hydrocarbons, and n-alkanes from polyurethane foam sorbents  

Microsoft Academic Search

Supercritical fluid extraction (SFE) with COâ is a rapid alternative to liquid solvent extraction for the recovery of organic air pollutants collected on polyurethane foam (PUF) sorbent plugs. Quantitative recovery (> 95%) of polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs) ranging from naphthalene to perylene, several heteroatom-containing PAHs, and n-alkanes ranging from Cââ to Cââ was achieved with 10-20 min

Steven B. Hawthorne; Mark S. Krieger; David J. Miller

1989-01-01

325

Source determination of polynuclear aromatic hydrocarbons in water and sediment of a creek in the Niger Delta region  

Microsoft Academic Search

Polynuclear aromatic hydrocarbons in surface water and sediment of Ekpan Creek of the Warri River were determined with GC Perkin-Elmer\\/Clarius 500. Compositional patterns of the PAHs were used to distinguish their sources in the aquatic system. The three diagnostic selected concentration ratios of polynuclear aromatic hydrocarbon isomer pairs confirmed that the PAHs concentrations in sediment of Ekpan Creek were from

Okoro Duke

326

Polycyclic Aromatic Hydrocarbons and Hopane in Malacca Coastal Water: 130 Years of Evidence for Their Land-Based Sources  

Microsoft Academic Search

Massive development over the past century has led to environmental oil-related pollution around the Malaysian city of Malacca. To characterize the concentration, sources, and origins of polycyclic aromatic hydrocarbons in Malacca’s coastal water in the Strait of Malacca, sediment cores from near shore and offshore were collected and analyzed. The highest concentration of total polycyclic aromatic hydrocarbons (PAHs) in the

Mahyar Sakari; Mohamad Pauzi Zakaria; Che Abd Rahim Mohamed; Nordin Haj Lajis; Mohd Harun Abdullah; Azadeh Shahbazi

2011-01-01

327

BN-Dibenzo[a,o]picenes: analogues of an unknown polycyclic aromatic hydrocarbon.  

PubMed

Reflecting on synthetic pinnacles: Whereas the parent hydrocarbon is not readily accessible, several examples of BN substituted-dibenzo[a,o]picenes can be prepared in two steps from known starting materials. These non-linear heptacene analogues are water-stable materials. Their preparation utilizes a potentially general method for preparing extended BN analogues of difficult-to-synthesize polycyclic aromatic hydrocarbon frameworks. PMID:23897598

Neue, Benedikt; Araneda, Juan F; Piers, Warren E; Parvez, Masood

2013-09-16

328

Peat fires as source of polycyclic aromatic hydrocarbons in soils  

NASA Astrophysics Data System (ADS)

Polycyclic aromatic hydrocarbons (PAHs) arrive from pyrogenic sources including volcanism and the combustion of oil products and plant materials. The production of PAHs during the combustion of plant materials was considered in a number of publications, but their results were mainly obtained in laboratory experiments. Insufficient data are available on the hightemperature production of PAHs in environmental objects. For example, natural fires are frequently related to the PAH sources in landscapes, but very little factual data are available on this topic. On Polistovskii reserve (Russia, Pskov region) the soil series were separated depending on the damage to the plants; these series included soils of plots subjected to fires of different intensities, as well as soils of the background plots. The series of organic and organomineral soils significantly differed in their PAH distributions. In this series, the concentration of PAHs in the upper horizons of the peat soils little varied or slightly decreased, but their accumulation occurred at a depth of 5-10 or 10-20 cm in the soils after the fires. For example, in the series of high moor soils, the content of PAHs in the upper horizons remained almost constant; significant differences were observed in the subsurface horizons: from 2 ng/g in the background soil to 70 ng/g after the fire. In the upper horizons of the oligotrophic peat soils under pine forests, the total PAH content also varied only slightly. At the same time, the content of PAHs in the soil series increased from 15 to 90 ng/g with the increasing pyrogenic damage to the plot. No clear trends of the PAH accumulation were recorded in the organomineral soils. The content of PAHs in the soddy-podzolic soil subjected to fire slightly decreased (from 20 to 10 ng/g) compared to the less damaged soil. In peat fires, the access of oxygen to the fire zone is lower than in forest fires. The oxygen deficit acts as a factor of the organic fragments recombination and PAH production; therefore, larger amounts of PAHs are formed in peat fires. In addition, the peat fires occur directly in the soil layer; therefore, larger amounts of the resulting polyarenes remain in the soils of the fire sites. PAHs also can be formed at the heating of organic matter on the areas adjacent to the fire sites. After the combustion of peat in fires, phenanthrene, chrysene, benz[a]pyrene, and tetraphene accumulate in soils. This is mainly the group of 4-nuclear compounds with the participation of 3-nuclear phenanthrene and 5-nuclear benz[a]pyrene. The formation of high-molecular weight compounds like benz[a]pyrene and, in some places, benzo[ghi]perylene is possible during smoldering under a low oxygen supply.

Tsibart, Anna

2013-04-01

329

Polycyclic Aromatic Hydrocarbons in an industrialized urban area  

NASA Astrophysics Data System (ADS)

Urbanization, agricultural intensification and industrialization are contributing to erosion, local and diffuse contamination and sealing of soil surfaces, resulting in soil quality degradation. Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in urban environments and considered good markers of anthropogenic activities such as traffic, industry, domestic heating and agriculture. Although they are subject to biodegradation and photodegradation, once in the soil, they tend to bind to the soil organic fraction. Estarreja is a small coastal town in the Northwestern Portuguese coast, with a close relation with the lagoon of Aveiro which supports a variety of biotopes (channels, islands with vegetation, mudflats, salt marshes and agricultural fields) of important ecological value. It supports an intensive and diversified agriculture, a variety of heavy and light industries and a population of about half a million people which is dependent on this resource. This is a very industrialized area, due to its five decades of chemical industry. This study aims to assess the impact of the urbanization and of the chemical industry in PAHs distribution. The survey and sampling method were based on pre-interpreted maps, aerial photographs, and directly checked in the field, in order to get an overall characterization of the area. Topsoils were collected from 34 sites, considering different land uses. Five land uses were chosen: ornamental gardens, parks, roadsides, forest and agricultural. Parameters such as soil pH (ISO method 10390:1994), total C, N, H, S percentages (microanalyser LECO, CNHS-932), organic matter (LOI at 430°), particle size distribution (Micromeritics® Sedigraph 5100), cation exchange capacity and exchangeable bases, were determined in order to have a general characterization of soil. Determination of the 16 EPA PAHs in soils was performed by GC/MS after a Soxhlet extraction and an alumina clean-up of extracts. Procedure blanks, duplicates and reference material were used in each extraction batch for quality control assessment. In what concerns the general parameters, Estarreja soils were characterized as slightly acid, with a median pHCaCl2 of 5.15, ranging from 3.12 and 6.88. The content in organic matter observed was relatively high, with a median of 4.6% and ranging from 1.8 to 45%. The median concentration of PAHs was 98 µg kg-1, ranging from 27 to 2,016 µg kg-1. The former value was found in an agricultural area and, together with another agricultural soil (with 1121 µgPAHs/kg), were considered heavily contaminated according to the classification given by Maliszewska-Kordybach. Moreover, eight samples were classified as weakly contaminated (PAHs between 200 and 600 µg/kg) and the remaining ones were not contaminated. The relative abundance of individual PAHs in Estarreja soils was evaluated, being the most abundant Fluoranthene and Pyrene followed by Benzo(b)fluoranthene, Phenanthrene and Crysene. These PAHs are the ones usually associated with the combustion of fossil fuel and other burnable materials, being this composition is typical for topsoil of European industrialized countries. Geostatistical methods were used to show the spatial variability of contaminants and the probability of exceeding the risk-based standards. The plots of concentration of PAHs on GIS highlight areas where the highest elements concentrations occur and the land use associated. These soil maps assemble important information for decision-making, allowing identifying possible sources of contamination, assess the suitability of soil to its use and to contribute for land use planning in accordance to soil characteristics. Acknowledgements: This work was supported by the Portuguese Foundation for Science and Technology (SFRH/BD/38418/2007) and by CESAM

Cachada, A.; Pereira, R.; Ferreira da Silva, E.; Duarte, A. C.

2009-04-01

330

Health Hazard Evaluation Report: HETA-2010-0156-3196, December 2013. Evaluation of Dermal Exposure to Polycyclic Aromatic Hydrocarbons in Fire Fighters.  

National Technical Information Service (NTIS)

The Health Hazard Evaluation Program carried out a study at a fire service training facility to assess exposures to airborne polycyclic aromatic hydrocarbons (PAHs) and other aromatic hydrocarbons. The purpose was to learn whether these substances pass th...

C. Mueller C. Striley D. Evans D. Sammons G. P. Horn J. Eisenberg J. Pleil J. Snawder K. W. Fent M. Stiegel S. Robertson V. Kochenderfer

2013-01-01

331

Identification and Comparative Genotoxicity of Polycyclic Aromatic Hydrocarbons and Related Nitrogen-Containing Heteroatomic Species in Products from Coal Liquefaction Processes.  

National Technical Information Service (NTIS)

A series of process distillation cuts from a solvent refined coal process were separated into polycyclic aromatic hydrocarbons (PAH) and nitrogen-containing polycyclic aromatic hydrocarbons (N-PAC) chemical classes and the fractions tested for biological ...

D. W. Later R. A. Pelroy D. D. Mahlum C. W. Wright M. L. Lee

1983-01-01

332

Aromatic hydrocarbons as indicators of origin and maturation for light oils from Panyu lower uplift in Pearl River Mouth basin  

Microsoft Academic Search

Aromatic fractions of six light oils and two source rock samples from Panyu (??) lower uplift of Pearl River Mouth basin were\\u000a analyzed using GC-MS (gas chromatography-mass spectrometric) technique. Thirteen aromatic series of hydrocarbons detected\\u000a such as biphenyls, naphthalenes, phenanthrenes, dibenzothiophenes (more than two hundred aromatic hydrocarbon compounds) were\\u000a used to analyze the origin and maturity of the light oils.

Xiaowen Guo; Sheng He

2009-01-01

333

Oxidation of polycyclic aromatic hydrocarbons by fungal isolates from an oil contaminated refinery soil  

Microsoft Academic Search

Background and Objective  Indigenous soil microorganisms are used for the biodegradation of petroleum hydrocarbons in oily waste residues from the petroleum\\u000a refining industry. The objective of this investigation was to determine the potential of indigenous strains of fungi in soil\\u000a contaminated with petroleum hydrocarbons to bio-degrade polycyclic aromatic hydrocarbons (PAH).\\u000a \\u000a \\u000a \\u000a Materials and Methods  Twenty one fungal strains were isolated from a soil

Zhongming Zheng; Jeffrey P. Obbard

2003-01-01

334

Vertical fluxes of aromatic and aliphatic hydrocarbons in the Northwestern Mediterranean Sea  

Microsoft Academic Search

Aliphatic and aromatic hydrocarbon fluxes were measured in time series sediment trap samples at 200m and at 1000m depths in the open Northwestern Mediterranean Sea, from December 2000 to July 2002. Averaged fluxes of n-alkanes, UCM and T-PAH35 were 2.96±2.60?gm?2d?1, 64±60?gm?2d?1 and 0.68±0.59?gm?2d?1, respectively. Molecular compositions of both hydrocarbon classes showed a contamination in petrogenic hydrocarbons well above the background

Rémi Deyme; Ioanna Bouloubassi; Marie-Hélène Taphanel-Valt; Juan-Carlos Miquel; Anne Lorre; Jean-Claude Marty; Laurence Méjanelle

2011-01-01

335

Enumeration and characterization of the soil microflora from hydrocarbon-contaminated soil sites able to mineralize polycyclic aromatic hydrocarbons (PAH)  

Microsoft Academic Search

The use of a plate screening technique allowed the direct isolation and quantification of polycylic aromatic hydrocarbon (PAH)-degrading bacteria from different soil sites. Bacteria that were able to grow on anthracene, phenanthrene, fluoranthene or pyrene as a sole carbon source were found with numbers between 103 and 105 colony-forming units (cfu)\\/g of soil dry weight, but only in samples that

M. Kästner; M. Breuer-Jammali; B. Mahro

1994-01-01

336

Hydrogen solubility in a chemical hydrogen storage medium, aromatic hydrocarbon, cyclic hydrocarbon, and their mixture for fuel cell systems  

Microsoft Academic Search

A synthetic type apparatus was designed to measure hydrogen solubility in four pure aromatic or cyclic hydrocarbons, benzene, cyclohexane, toluene, and methylcyclohexane, and two equimolar binary mixtures, benzene + cyclohexane, and methylcyclohexane + toluene. The experimental temperature was 303.15K, and the pressure range from 0.887 to 4.827MPa. The hydrogen solubility increased linearly with the pressure following the Henry's law. The

Tomoya Tsuji; Yoshiko Shinya; Toshihiko Hiaki; Naotsugu Itoh

2005-01-01

337

Isolation, characterization of Rhodococcus sp. P14 capable of degrading high-molecular-weight polycyclic aromatic hydrocarbons and aliphatic hydrocarbons  

Microsoft Academic Search

Rhodococcus sp. P14 was isolated from crude oil-contaminated sediments. This strain was capable of utilizing three to five rings polycyclic aromatic hydrocarbons (PAHs) including phenanthrene (Phe), pyrene (Pyr), and benzo[a]pyrene (BaP) as a sole carbon and energy source. After cultivated with 50mg\\/L of each PAH, strain P14 removed 43% Phe, 34% Pyr and 30% BaP in 30 d. Four different

Xiaohui Song; Yan Xu; Gangmin Li; Ying Zhang; Tongwang Huang; Zhong Hu

2011-01-01

338

COMPARISON OF QUANTUM MECHANICAL METHODS TO COMPUTE THE BIOLOGICALLY RELEVANT REACTIVITIES OF CYCLOPENTA POLYCYCLIC AROMATIC HYDROCARBONS  

EPA Science Inventory

In computational studies to understand the interaction of polycyclic aromatic hydrocarbons (PAHS) with biomolecular systems, the semi-empirical method AM1 has been used to determine the geometry of the PAH, its metabolites and relevant intermediates. umber of studies have shown t...

339

Characterization of subsurface polycyclic aromatic hydrocarbons at the Deepwater Horizon site  

Microsoft Academic Search

Here, we report the initial observations of distributions of polycyclic aromatic hydrocarbons (PAH) in subsurface waters near the Deepwater Horizon oil well site (also referred to as the Macondo, Mississippi Canyon Block 252 or MC252 well). Profiles of in situ fluorescence and beam attenuation conducted during 9-16 May 2010 were characterized by distinct peaks at depths greater than 1000 m,

Arne-R. Diercks; Raymond C. Highsmith; Vernon L. Asper; DongJoo Joung; Zhengzhen Zhou; Laodong Guo; Alan M. Shiller; Samantha B. Joye; Andreas P. Teske; Norman Guinasso; Terry L. Wade; Steven E. Lohrenz

2010-01-01

340

APPLICATION OF EPA METHOD 610 TO THE ANALYSIS OF POLYNUCLEAR AROMATIC HYDROCARBONS IN LEACHATE SAMPLES  

EPA Science Inventory

This report summarizes the results of a spiking study performed on a sanitary landfill leachate matrix. Fifteen polynuclear aromatic hydrocarbons (PNAs) were dosed into the landfill leachate and analyzed using EPA Method 610. The results show that the PNAs containing two, three, ...

341

Polycyclic Aromatic Hydrocarbon-Induced Cytotoxicity in Cultured Rat Sertoli Cells Involves Differential Apoptotic Response  

Microsoft Academic Search

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous and persistent environmental contami- nants. Some PAHs are carcinogens and may affect the male reproductive system. Therefore, we exposed cultured rat Sertoli cells to a variety of PAHs to determine possible direct toxic effects on the cells of the seminiferous epithelium. Sertoli cells were chosen because they support germ cell development and maintain spermatogenesis.

Samir S. Raychoudhury; Dana Kubinski

2002-01-01

342

Characterization of polycyclic aromatic compounds in diesel exhaust particulate extract responsible for aryl hydrocarbon receptor activity  

NASA Astrophysics Data System (ADS)

Chemical fractions of a model diesel exhaust particulate extract, notably the fraction containing polycyclic aromatic hydrocarbons (PAH) (Fraction II), mono-nitro PAH (Fraction III), and dinitro-PAH (Fraction IV) have been shown to displace binding of 2,3,7,8-tetrachloro[1,6-[ 3H

Soontjens, Carol D.; Holmberg, Kristina; Westerholm, Roger N.; Rafter, Joseph J.

343

Development of a catabolically significant genetic probe for polycyclic aromatic hydrocarbon-degrading Mycobacteria in soil  

Microsoft Academic Search

A gene probe for the detection of polycyclic aromatic hydrocarbon (PAH) induced nidB and nidA dioxygenase genes has been designed from Mycobacteria JLS, KMS, and MCS. The probe detects a catabolic gene involved in the initial steps of PAH biodegradation in mycobacteria. The gene probe is comprised of three PCR primer sets designed to detect the genes that code for

Kevin Hall; Charles D. Miller; Darwin L. Sorensen; Anne J. Anderson; Ronald C. Sims

2005-01-01

344

Genotypic and phenotypic responses of a riverine microbial community to polycyclic aromatic hydrocarbon contamination  

Microsoft Academic Search

The phenotypic and genotypic adaptation of a freshwater sedimentary microbial community to elevated levels of polycyclic aromatic hydrocarbons (PAHs) was determined by using an integrated biomolecular approach. Central to the approach was the use of phospholipid fatty acid (PLFA) profiles to characterize the microbial community structure and nucleic acid analysis to quantify the frequency of degradative genes. The study site

DONALD E. LANGWORTHY; R. H. Findlay; R. D. Stapleton; G. S. Sayler

1998-01-01

345

Toxicity of polycyclic aromatic hydrocarbons. (Latest citations from Pollution abstracts). Published Search  

SciTech Connect

The bibliography contains citations concerning the toxicity and biochemical effects of aromatic polycyclic hydrocarbons. Citations discuss air, water, soil, and sediment pollution and control. Topics include vehicle emissions and control, pollutant pathways, carcinogens and mutagenic activity, and photoinduced toxicity. Food contamination, environmental monitoring, and soil contamination along highways are examined. (Contains 50-250 citations and includes a subject term index and title list.)

NONE

1995-07-01

346

Distribution, sources and potential toxicological significance of polycyclic aromatic hydrocarbons (PAHs) in Taihu Lake sediments, China  

Microsoft Academic Search

Taihu Lake is one of the largest freshwater lakes in China. The lake is very shallow with a mean depth of 1.9 m and an area of 2428 km2. This is the first time that polycyclic aromatic hydrocarbon concentrations in the surface sediments of Taihu Lake have been analyzed. A distinctive spatial distribution of PAHs was observed. Sediments from Lake

Qu Wenchuan; Mike Dickman; Fan Chengxin; Wang Sumin; Su Chenwei; Zhang Lu; Zou Huixian

2002-01-01

347

Interaction of multiply charged ions with isolated polycyclic aromatic hydrocarbon molecules  

NASA Astrophysics Data System (ADS)

The interaction of multiply charged ions (He2+, O3+, and Xe20+, v <= 0.6 a.u.) with gas phase pericondensed polycyclic aromatic hydrocarbon (PAH) molecules (pyrene and coronene) was studied. Positively charged ionic products were analyzed with a linear time-of-flight mass spectrometer.

?awicki, A.; Capron, M.; Maisonny, R.; Maclot, S.; Lattouf, E.; Méry, A.; Rangama, J.; Holm, A. I. S.; Zettergren, H.; Seitz, F.; Johansson, H. A. B.; Rosén, S.; Schmidt, H. T.; Cederquist, H.; Manil, B.; Adoui, L.; Rousseau, P.; Huber, B. A.

2012-11-01

348

Field comparison of polyurethane foam and XAD-2 resin for air sampling for polynuclear aromatic hydrocarbons  

Microsoft Academic Search

A study of the sampling efficiency for polynuclear aromatic hydrocarbons (PAH) in air of two adsorbents, XAD-2 resin and polyurethane foam (PUF), was performed under summer and winter ambient conditions. Two aspects were investigated: (1) collection efficiency for ambient PAH vapor and (2) retention efficiency for native and perdeuteriated PAH spiked onto the adsorbents before sampling. The XAD-2 resin had

Jane C. Chuang; Steve W. Hannan; Nancy K. Wilson

1987-01-01

349

ELECTRON AFFINITIES OF POLYNUCLEAR AROMATIC HYDROCARBONS AND NEGATIVE ION CHEMICAL IONIZATION SENSITIVITIES  

EPA Science Inventory

Negative-ion chemical-ionization mass spectrometry (NICI MS) has the potential to be a very useful technique in identifying various polycyclic aromatic hydrocarbons (PAHs) in soil and sediment samples. Some PAHs give much stronger signals under NICI MS conditions than others. On ...

350

EPOXIDE RING OPENING AND RELATED REACTIVITIES OF CYCLOPENTAL POLYCYCLIC AROMATIC HYDROCARBONS: QUANTUM MECHANICAL STUDIES  

EPA Science Inventory

For a series of cyclopenta-polynuclear aromatic hydrocarbons, epoxidated in the cyclopenta ring, semi-empirical AM1 calculations, and single point ab initio calculations using the 3-21g split valence basis set, have been performed for the each carbocation that might be formed by ...

351

Health risk assessment for traffic policemen exposed to polycyclic aromatic hydrocarbons (PAHs) in Tianjin, China  

Microsoft Academic Search

In China, traffic policemen have to stand for several hours a day at the road intersections with high vehicle flows. To assess their exposure to airborne carcinogenic polycyclic aromatic hydrocarbons (PAHs) during their working time, a preliminary study was conducted to measure the personal exposure level to PAHs. And a probabilistic incremental lifetime cancer risk (ILCR) model together with the

Yandi Hu; Zhipeng Bai; Liwen Zhang; Xue Wang; Li Zhang; Qingchan Yu; Tan Zhu

2007-01-01

352

Minimal clean-up and rapid determination of polycyclic aromatic hydrocarbons in instant coffee  

Microsoft Academic Search

The essential aim of this work is the development of a simple, fast, quantitative and economic method for polycyclic aromatic hydrocarbons (PAHs) potentially generated by roasting coffee beans, which is the most important process in the coffee industry for the development of the characteristic flavour of the bean mix. The PAHs were chosen because they differed in the number of

Mercedes Sonia Garc??a-Falcón; Beatriz Cancho-Grande; Jesús Simal-Gándara

2005-01-01

353

Diversity of ndo Genes in Mangrove Sediments Exposed to Different Sources of Polycyclic Aromatic Hydrocarbon Pollution  

Microsoft Academic Search

Polycyclic aromatic hydrocarbon (PAH) pollutants originating from oil spills and wood and fuel combustion are pollutants which are among the major threats to mangrove ecosystems. In this study, the composition and relative abundance in the sediment bacterial communities of naphthalene dioxygenase (ndo) genes which are important for bacterial adaptation to environmental PAH contamination were investigated. Three urban mangrove sites which

Newton C. Marcial Gomes; Ludmila R. Borges; Rodolfo Paranhos; Fernando N. Pinto; Ellen Krogerrecklenfort; Leda C. S. Mendonca-Hagler; Kornelia Smalla

2007-01-01

354

Polycyclic aromatic hydrocarbons in water and sediment of the Baltic Sea  

Microsoft Academic Search

Between 1992 and 1994, the distribution of 15 polycyclic aromatic hydrocarbons (PAHs) was investigated in seawater and surface sediments of the Baltic Sea. The analysis of PAHs in seawater is very difficult due to the low concentration. High separation capability is required. A method for analysing very low concentrations of PAHs is presented. The method is based on the high-performance

G. Witt

1995-01-01

355

Characterization of a Polycyclic Aromatic Hydrocarbon–Degrading Microbial Consortium from a Petrochemical Sludge Landfarming Site  

Microsoft Academic Search

Anthracene, phenanthrene, and pyrene are polycyclic aromatic hydrocarbon (PAHs) that display both mutagenic and carcinogenic properties. They are recalcitrant to microbial degradation in soil and water due to their complex molecular structure and low solubility in water. This study presents the characterization of an efficient PAH (anthracene, phenanthrene, and pyrene)-degrading microbial consortium, isolated from a petrochemical sludge landfarming site. Soil

Rodrigo J. S. Jacques; Benedict C. Okeke; Fatima M. Bento; Maria C. R. Peralba; Flávio A. O. Camargo

2007-01-01

356

Comparative studies on lignin and polycyclic aromatic hydrocarbons degradation by basidiomycetes fungi  

Microsoft Academic Search

A total of 130 wild basidiomycetes fungi were collected and identified. The polycyclic aromatic hydrocarbons (PAHs) degradation by the potential Phellinus sp., Polyporus sulphureus (in liquid state fermentation (LSF), solid state fermentation (SSF), in soil) and lignin biodegradation were compared with those of a bacterial isolate and their corresponding cocultures. The PAHs degradation was higher in LSF and the efficiency

A. Arun; M. Eyini

2011-01-01

357

Products from the Incomplete Metabolism of Pyrene by Polycyclic Aromatic Hydrocarbon-Degrading Bacteria  

Microsoft Academic Search

Pyrene is a regulated pollutant at sites contaminated with polycyclic aromatic hydrocarbons (PAH). It is mineralized by some bacteria but is also transformed to nonmineral products by a variety of other PAH- degrading bacteria. We examined the formation of such products by four bacterial strains and identified and further characterized the most apparently significant of these metabolites. Pseudomonas stutzeri strain

CHIKOMA KAZUNGA; MICHAEL D. AITKEN

2000-01-01

358

Numerical and Genetic Analysis of Polycyclic Aromatic Hydrocarbon-Degrading Mycobacteria  

Microsoft Academic Search

Ability to degrade high molecular weight polycyclic aromatic hydrocarbons (PAHs) has been found in diverse species of fast-growing mycobacteria. This study included several PAH-degrading mycobacteria from heavily contaminated sites and an uncontaminated humus soil in the Natural Park, Schwäbische Alb, Germany. The numerical analysis with a total of 131 tests showed that isolates from humus soil and contaminated sites had

Yong-Hak Kim; Karl-H. Engesser; Carl E. Cerniglia

2005-01-01

359

Enumeration and phylogenetic analysis of polycyclic aromatic hydrocarbon-degrading marine bacteria from Puget Sound sediments  

Microsoft Academic Search

Polycyclic aromatic hydrocarbons (PAHs) are primarily released into the environment through anthropomorphic sources. PAH degradation has been known to occur in marine sediments. This paper describes the enumeration, isolation, and preliminary characterization of PAH-degrading strains from Puget Sound sediments. 38 refs., 3 figs., 3 tabs.

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

1996-01-01

360

Enrichment, Isolation, and Phylogenetic Identification of Polycyclic Aromatic Hydrocarbon-Degrading Bacteria from Elizabeth River Sediments  

Microsoft Academic Search

The diversity of indigenous bacteria in sediments from several sites in the Elizabeth River (Virginia) able to degrade multiple polycyclic aromatic hydrocarbons (PAHs) was investigated by the use of classical selective enrichment and molecular analyses. Enrichment cultures containing naphthalene, phenan- threne, fluoranthene, or pyrene as a sole carbon and energy source were monitored by denaturing gradient gel electrophoresis (DGGE) to

Edward J. Hilyard; Joanne M. Jones-Meehan; Barry J. Spargo; Russell T. Hill

2008-01-01

361

Products from the incomplete metabolism of pyrene by polycyclic aromatic hydrocarbon-degrading bacteria  

Microsoft Academic Search

Pyrene is a regulated pollutant at sites contaminated with polycyclic aromatic hydrocarbons (PAH). It is mineralized by some bacteria but is also transformed to nonmineral products by a variety of other PAH-degrading bacteria. The authors examined the formation of such products by four bacterial strains and identified and further characterized the most apparently significant of these metabolites. Pseudomonas stutzeri strain

C. Kazunga; M. D. Aitken

2000-01-01

362

A MOLECULAR MODELING ANALYSIS OF POLYCYCLIC AROMATIC HYDROCARBON BIODEGRADATION BY NAPHTHALENE DIOXYGENASE  

Microsoft Academic Search

A theoretical analysis was performed to examine the role of naphthalene dioxygenase (NDO) enzymes in determining differences in biodegradability and biodegradation rates of two- to four-ring polycyclic aromatic hydrocarbons (PAHs) via oxy- genation and desaturation reactions. Investigation of the thermodynamics of PAH biodegradation reactions catalyzed by NDO revealed that enthalpies of reaction can explain reaction patterns or regioselectivity of the

Kristine H. Wammer; Catherine A. Peters

2006-01-01

363

Determination of polycyclic aromatic hydrocarbons in alcoholic drinks and the identification of their potential sources  

Microsoft Academic Search

Some polycyclic aromatic hydrocarbons (PAHs), particularly those with a high molecular mass, have been classified as probably being carcinogenic to humans by the International Agency for Research on Cancer (IARC). The significance of the determination of PAHs is reflected by the special attention the European Union is paying to regulating their maximum allowed levels in various types of foodstuffs. Like

M. S. García-Falcón; J. Simal-Gándara

2005-01-01

364

MEASUREMENTS OF POLYCYCLIC AROMATIC HYDROCARBONS IN AMBIENT AIR PARTICULATES IN NORTHERN NEW ENGLAND  

EPA Science Inventory

The paper gives results of measuring polycyclic aromatic hydrocarbons (PAHs) in ambient air particulates in Northern New England. Standard high-volume filter samples of ambient-air particulates were collected during several heating seasons in a semi-rural village, a rural area, a...

365

Evidence for polynuclear aromatic hydrocarbons in the diet of bottom-feeding fish  

Microsoft Academic Search

Among environmental pollutants, polynuclear aromatic hydrocarbons (PAH) are of interest because of their widespread occurrence and the human carcinogenicity of their metabolic products. Most PAH are relatively water insoluble and ultimately are deposited in sediments. In localized areas of eastern Lake Erie, sediments have been shown to have high concentrations of PAH. As a part of an ongoing research on

A. E. Maccubbin; P. Black; L. Trzeciak; J. J. Black

1985-01-01

366

Photoinduced toxicity of the polycyclic aromatic hydrocarbon, fluoranthene, on the coral, Porites divaricata  

Microsoft Academic Search

The synergistic effect of ultraviolet radiation (UVR) and a polycyclic aromatic hydrocarbon (PAH) was tested on the coral Poritesdivaricata. Small branches were incubated in different concentrations of fluoranthene followed by exposure to ecologically relevant levels of natural solar radiation, with and without UVR. Exposure to the highest concentration of fluoranthene (60 ? g L) resulted in decreased photochemical efficiency of

María Del Carmen GuzmáN Martínez; Patricia Ramírez Romero; Anastazia T. Banaszak

2007-01-01

367

Effect of irradiance spectra on the photoinduced toxicity of three polycyclic aromatic hydrocarbons  

Microsoft Academic Search

Photoinduced toxicity of polycyclic aromatic hydrocarbons (PAHs) is dependent on the concentration of compounds present and the dose of light received. Of the light present, only those wavelengths absorbed by the compound have the potential to initiate the photochemical events underlying phototoxicity. This suggests that variation in light spectra present in natural waters, arising from variation in dissolved organic carbon

S. A. Diamond; D. R. Mount; L. P. Burkhard; G. T. Ankley; E. A. Makynen; E. N. Leonard

2000-01-01

368

PEER CONSULTATION WORKSHOP ON APPROACHES TO POLYCYCLIC AROMATIC HYDROCARBON (PAH) HEALTH ASSESSMENT  

EPA Science Inventory

U.S. EPA's Integrated Risk Information System (IRIS) Program has initiated a health assessment for polycylic aromatic hydrocarbon (PAH) mixtures. Currently, the IRIS database contains entries developed in the early 1990s for 15 non-methylated PAHs with three or more rings. These...

369

Biological and abiotic losses of polynuclear aromatic hydrocarbons (PAHs) from soils freshly amended with sewage sludge  

Microsoft Academic Search

Sewage sludge containing typical indigenous concentrations of polynuclear aromatic hydrocarbons (PAHs) was applied to several different soils in glass microcosms. Biologically active and sterilized soils were monitored for PAH content over a period of approximately 205 d. Agricultural soils with and without previous exposure to sewage sludge were tested, together with a forest soil and a soil from a major

S. R. Wild; K. C. Jones

1993-01-01

370

PERSONAL EXPOSURES TO POLYCYCLIC AROMATIC HYDROCARBONS ASSOCIATED WITH THE NHEXAS PILOT  

EPA Science Inventory

Personal exposure monitoring for select polycyclic aromatic hydrocarbons (PAHs) was performed as part of the National Human Exposure Assessment Survey (NHEXAS) Pilot Study in Baltimore, MD. Twenty-four hour PM10 sample collections (~5.7 m3) were performed using personal envi...

371

Cancer risk from occupational and environmental exposure to polycyclic aromatic hydrocarbons  

Microsoft Academic Search

Epidemiologic evidence on the relationship between polycyclic aromatic hydrocarbons (PAH) and cancer is reviewed. High occupational exposure to PAHs occurs in several industries and occupations. Covered here are aluminum production, coal gasification, coke production, iron and steel foundries, tar distillation, shale oil extraction, wood impregnation, roofing, road paving, carbon black production, carbon electrode production, chimney sweeping, and calcium carbide production.

Paolo Boffetta; Nadia Jourenkova; Per Gustavsson

1997-01-01

372

Anaerobic Degradation of Polycyclic Aromatic Hydrocarbons and Alkanes in Petroleum-Contaminated Marine Harbor Sediments  

Microsoft Academic Search

Although polycyclic aromatic hydrocarbons (PAHs) have usually been found to persist under strict anaer- obic conditions, in a previous study an unusual site was found in San Diego Bay in which two PAHs, naphthalene and phenanthrene, were oxidized to carbon dioxide under sulfate-reducing conditions. Further investigations with these sediments revealed that methylnaphthalene, fluorene, and fluoranthene were also anaerobically oxidized to

JOHN D. COATES; JOAN WOODWARD; JON ALLEN; PAUL PHILP; DEREK R. LOVLEY

1997-01-01

373

Polycyclic Aromatic Hydrocarbons in Surface Sediments Around England and Wales, and Their Possible Biological Significance  

Microsoft Academic Search

Concentrations of polycyclic aromatic hydrocarbons (PAH) were determined in sediments taken at offshore, coastal and estuarine sites around the UK during the period 1993–1996. In all, 99 samples were taken from 80 locations, including 48 of the stations established under the UK National Monitoring Programme. Fifteen individual parent PAH compounds were determined using a method incorporating an ultrasonication extraction step,

R. J. Woodhead; R. J. Law; P. Matthiessen

1999-01-01

374

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

Microsoft Academic Search

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

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

1993-01-01

375

Sedimentary record of anthropogenic and biogenic polycyclic aromatic hydrocarbons in San Francisco Bay, California  

Microsoft Academic Search

Dated sediment cores collected from Richardson and San Pablo Bays in San Francisco Bay were used to reconstruct a history of polycyclic aromatic hydrocarbon (PAH) contamination. The sedimentary record of PAHs in Richardson Bay shows that anthropogenic inputs have increased since the turn of the century, presumably as a result of increasing urbanization and industrialization around the Bay Area. Concentrations

Wilfred E. Pereira; Frances D. Hostettler; Samuel N. Luoma; Alexander van Geen; Christopher C. Fuller; Roberto J. Anima

1999-01-01

376

Urban runoff as a source of polycyclic aromatic hydrocarbons to coastal waters  

Microsoft Academic Search

Urban runoff samples collected from four storm drains, each serving a different land use, were analyzed for selected polycyclic aromatic hydrocarbons (PAHs) by gas chromatography. The PAH concentrations varied widely during the history of each storm and appeared to be most concentrated in first or second flushes. Higher molecular weight PAHs were mostly found associated with the particulates and were

Eva J. Hoffman; Gary L. Mills; James S. Latimer; James G. Quinn

1984-01-01

377

One-electron oxidation in the degradation of creosote polycyclic aromatic hydrocarbons by Phanerochaete chrysoporium  

Microsoft Academic Search

The abilities of whole cultures of Phanerochaete chrysosporium and P. chrysosporium manganese peroxidase-mediated lipid peroxidation reactions to degrade the polycyclic aromatic hydrocarbons (PAHs) found in creosote were studied. The disappearance of 12 three- to six-ring PAHs occurred in both systems. Both in vivo and in vitro, the disappearance of all PAHs was found to be very strongly correlated with ionization

Bill W. Bogan; R. T. Lamar

1995-01-01

378

Dissipation of 3–6-ring polycyclic aromatic hydrocarbons in the rhizosphere of ryegrass  

Microsoft Academic Search

Plants may contribute to the biodegradation of polycyclic aromatic hydrocarbons (PAHs) in contaminated soils. Different mechanisms have been proposed, such as an increase in microbial numbers, but are not clearly elucidated. This study investigates the dissipation of a mixture of eight PAHs, ranging from 3 to 6 rings, in the rhizosphere of ryegrass (Lolium perenne L.). Two pot experiments were

P Binet; J. M Portal; C Leyval

2000-01-01

379

Dry deposition of particulate polychlorinated biphenyls and polycyclic aromatic hydrocarbons to Lake Michigan  

Microsoft Academic Search

Dry deposition was collected from November 1993 to October 1995 at multiple sites within the Lake Michigan basin to estimate fluxes of particulate polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) as part of the Lake Michigan Mass Balance Study (LMMBS). Samples were also collected during the Atmospheric Exchange over Lakes and Oceans (AEOLOS) project to estimate fluxes to coastal

Thomas P. Franz; Steven J. Eisenreich; Thomas M. Holsen

1998-01-01

380

New SERS Substrates For Polycyclic Aromatic Hydrocarbon (PAH) Detection: Towards Quantitative SERS Sensors For Environmental Analysis  

SciTech Connect

In the investigation of chemical pollutions, such as PAHs (Polycyclic Aromatic Hydrocarbons) at low concentration in aqueous medium, surface-enhanced Raman scattering (SERS) stands for an alternative to the inherent low cross-section of normal Raman scattering. Indeed, SERS is a very sensitive spectroscopic technique due to the excitation of the surface plasmon modes of the nanostructured metallic film.

Peron, O. [Service Interfaces et Capteurs, Departement Recherches et Developpements Technologiques, IFREMER, BP70, 29280 Plouzane (France); Laboratoire de Nanotechnologie et d'instrumentation Optique, Institut Charles Delaunay, FRE 2848, Universite de technologie de Troyes, 12 rue Marie Curie, 10010 Troyes (France); Rinnert, E.; Compere, C. [Service Interfaces et Capteurs, Departement Recherches et Developpements Technologiques, IFREMER, BP70, 29280 Plouzane (France); Toury, T. [Laboratoire de Nanotechnologie et d'instrumentation Optique, Institut Charles Delaunay, FRE 2848, Universite de technologie de Troyes, 12 rue Marie Curie, 10010 Troyes (France); Lamy de la Chapelle, M. [Laboratoire CSPBAT (FRE 3043), UFR SMBH, Universite Paris XIII, 74 rue Marcel Cachin, 93017 Bobigny (France)

2010-08-06

381

Sediment porewater partitioning of polycyclic aromatic hydrocarbons in three cores from Boston Harbor, Massachusetts  

USGS Publications Warehouse

Polycyclic aromatic hydrocarbon (PAH) concentrations were measured in sediments and porewaters isolated from three cores from Boston Harbor, MA. Measured porewater PAH concentrations were significantly lower than the concentrations predicted by two- and three-phase equilibrium partitioning models. We hypothesize that only a fraction of the measured sediment PAH concentrations was available to partition rapidly into sediment porewaters. ?? 1995 American Chemical Society.

Mcgroddy, S. E.; Farrington, J. W.

1995-01-01

382

Influence of ultraviolet light on the toxicity of sediments contaminated with polycyclic aromatic hydrocarbons  

Microsoft Academic Search

Standard 10-d toxicity tests were conducted with freshwater benthic invertebrates using sediments containing a range of concentrations of polycyclic aromatic hydrocarbons (PAHs). The assays were performed both under normal laboratory fluorescent light and ultraviolet (UV) light, which mimicked wavelengths present in sunlight, at about 10% of ambient solar intensity. In sediments with elevated PAH concentrations, tests conducted with UV light

Gerald T. Ankley; Scott A. Collyard; Philip D. Monson; Patricia A. Kosian

1994-01-01

383

Microbial degradation of polycyclic aromatic hydrocarbons: effect of substrate availability on bacterial growth kinetics  

Microsoft Academic Search

It is demonstrated that bacterial growth on crystalline or adsorbed polycyclic aromatic hydrocarbons can result in a linear increase in biomass concentration. A simple mathematical approach is presented, showing that under these circumstances mass transfer from the solid phase to the liquid phase is rate-limiting for growth.

F. Volkering; A. M. Breure; A. Sterkenburg; J. G. van Andel

1992-01-01

384

Effects of aqueous chemistry on the binding of polycyclic aromatic hydrocarbons by dissolved humic materials  

Microsoft Academic Search

The influence of solution chemistry on the binding of three polycyclic aromatic hydrocarbons (PAHs) by well-characterized humic material (Suwannee River humic and fulvic acid) was examined by using fluorescence quenching techniques. The experiments show that binding is complete within 3 min and that the fluorescence of PAH compounds associated with the humic substances is fully quenched as evidenced by quantum

Mark A. Schlautman; James J. Morgan

1993-01-01

385

A review of atmospheric polycyclic aromatic hydrocarbons: Sources, fate and behavior  

Microsoft Academic Search

A review has been written to assess the sources, fate and behavior of polycyclic aromatic hydrocarbons (PAH) in the atmosphere. PAH are formed mainly by anthropogenic processes, especially the combustion of organic fuels. PAH concentration in air will reflect the location of source emitters, with high concentrations corresponding with urban and industrial areas. PAH are however ubiquitous contaminants of the

S. O. Baek; R. A. Field; M. E. Goldstone; P. W. Kirk; J. N. Lester; R. Perry

1991-01-01

386

Ambient and biological monitoring of cokeoven workers: determinants of the internal dose of polycyclic aromatic hydrocarbons  

Microsoft Academic Search

Polycyclic aromatic hydrocarbons (PAH) were measured in the breathing zone air of 56 battery workers at two cokeovens during three consecutive days. The concentration of total PAH ranged up to 186 micrograms\\/m3. Preshift and end of shift urine samples were collected to determine 1-hydroxypyrene, a metabolite of pyrene. Control urine samples were available from 44 workers in the shipping yard

F J Jongeneelen; F E van Leeuwen; S Oosterink; R B Anzion; F van der Loop; R P Bos; H G van Veen

1990-01-01

387

Bioconcentration of polycyclic aromatic hydrocarbons in vegetables grown in an industrial area  

Microsoft Academic Search

The polycyclic aromatic hydrocarbon (PAH) content was determined in the inner tissue of various vegetable species and their growing environment (soil and atmosphere) in the greater industrial area of Thessaloniki, northern Greece. The lower molecular weight compounds dominated in both vegetable leaves and roots. Statistical analysis of variance showed that species and season are the factors that significantly affect PAH

A. M. Kipopoulou; E. Manoli; C. Samara

1999-01-01

388

Characterization of polycyclic aromatic hydrocarbons in motor vehicle fuels and exhaust emissions  

Microsoft Academic Search

Motor vehicles are a significant source of polycyclic aromatic hydrocarbon (PAH) emissions. Improved understanding of the relationship between fuel composition and PAH emissions is needed to determine whether fuel reformulation is a viable approach for reducing PAH emissions. PAH concentrations were quantified in gasoline and diesel fuel samples collected in summer 1997 in northern California. Naphthalene was the predominant PAH

Linsey C. Marr; Thomas W. Kirchstetter; Robert A. Harley; S. K. Hammond; A. H. Miguel

1999-01-01

389

Polycyclic aromatic hydrocarbons in soil and air: statistical analysis and classification by the SIMCA method  

Microsoft Academic Search

Soil samples from 12 locations in Norway have been analyzed for 9 polycyclic aromatic hydrocarbons (PAH). The same unsubstituted PAH have been determined in air samples collected near an aluminum reduction plant. Analysis by high-resolution gas chromatography-mass spectroscopy in the selected ion mode showed concentrations in soil ranging from less than 1 ppb (detection limit) to 993 ppb for individual

Nils B. Vogt; Frode Brakstad; Karin Thrane; Svein Nordenson; Jostein Krane; Eli Aamot; Knut Kolset; Kim Esbensen; Eiliv Steinnes

1987-01-01

390

Kinetics of urea adduct formation in the presence of aromatic hydrocarbons  

Microsoft Academic Search

Here, we are reporting on studies of the influence of aromatic hydrocarbons on adduct formation, with a view toward establishing the relationship between their adsorption interaction and their inhibiting properties. In forming the adducts we used n-heptadecane as the starting material; the urea was crystalline material in \\

é. L. Borovneva; A. N. Belousov; A. G. Martynenko; R. A. Martirosov

1979-01-01

391

Black Carbon in Marine Sediments: Quantification and Implications for the Sorption of Polycyclic Aromatic Hydrocarbons.  

National Technical Information Service (NTIS)

Sorption is a key factor in determining the fate of polycyclic aromatic hydrocarbons (PAHs) in the environment. Here, PAH sorption is proposed as the sum of two mechanisms: absorption into a biogenic, organic carbon (OC) fraction and adsorption onto a com...

A. Accardi-Dey

2003-01-01

392

EXTRACTION AND DETERMINATION OF SELECTED POLYCYCLIC AROMATIC HYDROCARBONS IN PLANT TISSUES  

EPA Science Inventory

A procedure has been developed for analysis of plant material for polycyclic aromatic hydrocarbons (PAHs). Sonication is used to extract the PAHs from homogenized plant material into acetonitrile and then the PAHs are partitioned into pentane. The pentane extract is fractionated ...

393

METHOD DEVELOPMENT AND MONITORING OF POLYNUCLEAR AROMATIC HYDROCARBONS IN SELECTED U.S. WATERS  

EPA Science Inventory

A method for concentration of trace quantities of the six representatives of polynuclear aromatic hydrocarbon (PAH) family has been developed and successfully applied to PAH monitoring in finished and raw waters. PAH are collected by passing water through polyurethane foam plugs....

394

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

EPA Science Inventory

Comparative studies of the effect of polycyclic aromatic hydrocarbon geometry on the hydrolysis of diol epoxides The interaction of the diol epoxides (DEs) of both planar and non-planar PAHs with water have been examined using quantum mechanical and molecular dynamics. Th...

395

Immunological disorders associated with polychlorinated biphenyls and related halogenated aromatic hydrocarbon compounds  

USGS Publications Warehouse

This review characterizes immunological disorders in fish associated with the widespread environmental contaminants, polychlorinated biphenyls (PCBs), and related halogenated aromatic hydrocarbons (HAHs). Special attention is devoted to comparing the sensitivity of fish species, identifying sensitive immunological endpoints and postulating mechanisms of action.

Noguchi, G. E.

1998-01-01

396

Characterization of polycyclic aromatic hydrocarbons (PAHs) on lime spray dryer (LSD) ash using different extraction methods  

Microsoft Academic Search

In this study, traditional Soxhlet, automatic Soxhlet and ultrasonic extraction techniques were employed to determine the speciation and concentration of polycyclic aromatic hydrocarbons (PAHs) on lime spray dryer (LSD) ash samples collected from the baghouse of a spreader stoker boiler. To test the efficiencies of different extraction methods, LSD ash samples were doped with a mixture of 16 US EPA

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

2006-01-01

397

Occurrence of Polycyclic Aromatic Hydrocarbons in Artisanal Palmero Cheese Smoked with Two Types of Vegetable Matter  

Microsoft Academic Search

Palmero cheese is a fresh smoked cheese from the Isle of Palma (Canary Islands), manufactured with goat's milk. To guarantee its safety, the occurrence of polycy- clic aromatic hydrocarbons (PAH) in artisanal Palmero cheese smoked with 2 types of vegetable matter (almond shells and dry prickly pear) was studied. The determi- nation of PAH includes extraction and clean-up steps, followed

M. D. Guillén; G. Palencia; P. Sopelana; M. L. Ibargoitia

2007-01-01

398

Measurement of Short and Long-Term Toxicity of Polycyclic Aromatic Hydrocarbons Using Luminescent Bacteria  

Microsoft Academic Search

Growing concern over environmental contamination has stimulated rigorous efforts to establish reliable biological monitoring assays. Methodology was developed for measuring photoinduced short- and long-term toxicity of an important group of contaminants, polycyclic aromatic hydrocarbons (PAHs), using the luminescent bacterium Vibrio fischeri. The toxicity of most PAHs can be greatly enhanced on exposure of a living organism and\\/or the chemicals to

Yousef S. El-Alawi; Brendan J. McConkey; D. George Dixon; Bruce M. Greenberg

2002-01-01

399

FATES AND BIOLOGICAL EFFECTS OF POLYCYCLIC AROMATIC HYDROCARBONS IN AQUATIC SYSTEMS  

EPA Science Inventory

This research project was conducted to test the hypothesis that fates of polycyclic aromatic hydrocarbons (PAH) in ecosystems can be predicted by mechanistic simulation models based on easily measured properties of the compounds in this homologous series. To accomplish this goal ...

400

Empirical modeling of soot formation in shock-tube pyrolysis of aromatic hydrocarbons  

NASA Technical Reports Server (NTRS)

A method for empirical modeling of soot formation during shock-tube pyrolysis of aromatic hydrocarbons is developed. The method is demonstrated using data obtained in pyrolysis of argon-diluted mixtures of toluene behind reflected shock waves. The developed model is in good agreement with experiment.

Frenklach, M.; Clary, D. W.; Matula, R. A.

1986-01-01

401

Measurement of Polycyclic Aromatic Hydrocarbons in Diesel Exhaust Gas by a Part Flow Process.  

National Technical Information Service (NTIS)

A new process for the quantitative analysis of polycyclic aromatic hydrocarbons is described in this report, where the samples are collected by extracting a part flow from the diluted exhaust gas. The important advantage of this method is that apart from ...

A. Hartung J. Kraft J. Schulze H. Hartwig K. H. Lies

1981-01-01

402

Examination of Apollo 17 surface fines for porphyrins and aromatic hydrocarbons  

NASA Technical Reports Server (NTRS)

An Apollo 17 surface fines sample 75081,78, collected from Station 5, was extracted and examined fluorometrically. No porphyrins were found with fluorometric methods capable of detecting 2 times 10 to the minus 14th moles/g of Ni-mesoporphyrin IX in the sample. Also aromatic hydrocarbons were undetected.

Rho, J. H.

1974-01-01

403

Dioxins, furans and polycyclic aromatic hydrocarbons emissions from a hospital and cemetery waste incinerator  

Microsoft Academic Search

An experimental campaign was carried out on a hospital and cemetery waste incineration plant in order to assess the emissions of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polycyclic aromatic hydrocarbons (PAHs). Raw gases were sampled in the afterburning chamber, using a specifically designed device, after the heat recovery section and at the stack. Samples of slags from the combustion

Giuseppe Mininni; Andrea Sbrilli; Camilla Maria Braguglia; Ettore Guerriero; Dario Marani; Mauro Rotatori

2007-01-01

404

Growth characteristics of polycyclic aromatic hydrocarbons in dimethyl ether diffusion flame  

Microsoft Academic Search

The growth characteristics of polycyclic aromatic hydrocarbons (PAHs) in laminar dimethyl ether (DME) diffusion flame were investigated experimentally, and we assumed that the growth of PAHs within the flame was predominantly due to methyl addition\\/cyclization (MAC) mechanism. Methane and propane laminar diffusion flames were also investigated for comparison, and their PAHs growth characteristics had been explained by reactions concerning acetylene

Kazuhiro Hayashida; Toshio Mogi; Kenji Amagai; Masataka Arai

2011-01-01

405

HIGH PURITY PNA HYDROCARBONS AND OTHER AROMATIC COMPOUNDS. SYNTHESIS AND PURIFICATION  

EPA Science Inventory

The synthesis and/or purification of a group of polynuclear aromatic (PNA) hydrocarbons, commonly found as pollutants in the environment, are described. The steps used in a given synthesis, the experiments carried out, and a presentation of some instrumental data obtained in esta...

406

Phototoxicity of individual polycyclic aromatic hydrocarbons and petroleum to marine invertebrate larvae and juveniles  

Microsoft Academic Search

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

Marguerite C. Pelletier; Robert M. Burgess; Kay T. Ho; Anne Kuhn; Richard A. McKinney; Stephan A. Ryba

1997-01-01

407

Modeling of nitro-polycyclic aromatic hydrocarbon formation and decay in the atmosphere  

Microsoft Academic Search

A reaction mechanism of polycyclic aromatic hydrocarbons (PAH) and nitro-PAH (NPAH) in the gas and particle phase in the atmosphere has been further evaluated and modified using outdoor smog chamber experimental results. Diesel exhaust emissions were added to a 190 m3 outdoor smog chamber and permitted to age under conditions of daylight and darkness. A sampling train consisting of an

Zhihua Fan; Danhua Chen; Parag Birla; Richard M. Kamens

1995-01-01

408

Sampling precautions for the measurement of nitrated polycyclic aromatic hydrocarbons in ambient air  

Microsoft Academic Search

Because of the toxicity of polycyclic aromatic hydrocarbons (PAHs) and of their oxidation products, such as nitrated and oxygenated PAHs (NPAHs and OPAHs), the determination of their concentrations is of great interest in terms of atmospheric pollution control. Then, normalisation of sampling procedures appears essential. In this context, this paper presents a comparison of particulate PAH, OPAH and NPAH concentrations

A. Albinet; E. Leoz-Garziandia; H. Budzinski; E. ViIlenave

2007-01-01

409

Atmospheric concentrations of polycyclic aromatic hydrocarbons and selected nitrated derivatives in Greater Cairo, Egypt  

Microsoft Academic Search

Polycyclic aromatic hydrocarbons (PAHs) and selected nitrated derivatives (NPAHs) in air were determined at two sites, El Dokki (a traffic site) and El Teppen (an industrial site) in Greater Cairo, Egypt, during the winter and summer seasons. The sites were selected to represent areas with different activities of Greater Cairo. The concentrations of fifteen PAHs having two to six rings

Hossam F. Nassar; Ning Tang; Takayuki Kameda; Akira Toriba; Mamdouh I. Khoder; Kazuichi Hayakawa

2011-01-01

410

ADSORPTION AND RECOVERY OF NITRATED POLYCYCLIC AROMATIC HYDROCARBONS ON HYBRID SURFACTANT EXPANDED ZIRCONIUM-PHOSPHATE  

Microsoft Academic Search

This paper focuses on the removal of nitro substituted polycyclic aromatic hydrocarbon compounds (NPAHs) from water using low cost synthesized zirconium phosphate mesoporous materials. These materials are lamellar type incorporating n-alkyl-(n = 12 and n = 16) trimethylamonium bromide molecules with different concentrations. For comparison of their performance as adsorbents and in the recovery of NPAH, their results were compared

M. Algarra; M. V. Jiménez; F. G. Sánchez; J. Soto; J. J. Jiménez; Joaquim C. G. Esteves da Silva

2009-01-01

411

Photoinduced Toxicity to Lake Erie Phytoplankton Assemblages from Intact and Photomodified Polycyclic Aromatic Hydrocarbons  

Microsoft Academic Search

Pulse amplitude modulated (PAM) chlorophyll-a fluorescence is a simple, rapid technique for measuring photosynthetic efficiency in plants and algae that could be a useful biomarker of toxicity in the aquatic environment. PAM Chlorophyll fluorescence was used to detect inhibition of photosynthesis in natural assemblages of Lake Erie phytoplankton incubated with both intact and photomodified polycyclic aromatic hydrocarbons. The maximum efficiency

Christopher A. Marwood; Ralph E. H. Smith; Murray N. Charlton; Keith R. Solomon; Bruce M. Greenberg

2003-01-01

412

Toxicity of aromatic polycyclic hydrocarbons. (Latest citations from the Life Sciences Collection database). Published Search  

SciTech Connect

The bibliography contains citations concerning the toxicity and biochemical effects of aromatic polycyclic hydrocarbons. Topics include effects on metabolism and liver activity, cellular responses, binding characteristics, and the occurrence and path of the compounds in food chains. Bioaccumulation studies in specific areas, and isolation and detection techniques are also considered. (Contains 250 citations and includes a subject term index and title list.)

Not Available

1993-11-01

413

Toxicity of aromatic polycyclic hydrocarbons. (Latest citations from the Life Sciences Collection data base). Published Search  

SciTech Connect

The bibliography contains citations concerning the toxicity and biochemical effects of aromatic polycyclic hydrocarbons. Topics include effects on metabolism and liver activity, cellular responses, binding characteristics, and the occurrence and path of the compounds in food chains. Bioaccumulation studies in specific areas, and isolation and detection techniques are also considered. (Contains 250 citations and includes a subject term index and title list.)

Not Available

1992-05-01

414

Toxicity of aromatic polycyclic hydrocarbons. (Latest citations from the Life Sciences Collection database). Published Search  

SciTech Connect

The bibliography contains citations concerning the toxicity and biochemical effects of aromatic polycyclic hydrocarbons. Topics include effects on metabolism and liver activity, cellular responses, binding characteristics, and the occurrence and path of the compounds in food chains. Bioaccumulation studies in specific areas, and isolation and detection techniques are also considered. (Contains 250 citations and includes a subject term index and title list.)

Not Available

1994-11-01

415

Distribution of Petroleum and Aromatic Hydrocarbons at a Former Crude Oil and Natural Gas Production Facility  

Microsoft Academic Search

Site characterization and remediation activities were performed at a former crude oil and natural gas production facility prior to redevelopment of the site. Field activities included delineation, excavation and segregation of approximately 1,250,000 m of soil impacted by total petroleum hydrocarbons (TPH) and the aromatic volatile organic compounds (VOCs) benzene, toluene, ethylbenzene, and xylenes (hereafter, collectively referred to as BTEX).

D. A. Soukup; A. L. Ulery; Steve Jones

2007-01-01

416

DEGRADATION OF POLYNUCLEAR AROMATIC HYDROCARBONS UNDER BENCH-SCALE COMPOST CONDITIONS  

EPA Science Inventory

The relationship between biomass growth and degradation of polynuclear aromatic hydrocarbons (PAHs) in soil, and subsequent toxicity reduction, was evaluated in 10 in-vessel, bench-scale compost units. Field soil was aquired from the Reilly Tar and Chemical Company Superfund site...

417

Polycyclic aromatic hydrocarbon burden in ambient air in selected Niger Delta communities in Nigeria  

Microsoft Academic Search

The Niger Delta area in Nigeria has major oil producing and refining centers that characterized enormous industrial activities, especially in the petroleum sector. These industrial processes release different kinds of atmospheric pollutants, of which there is paucity of information on their levels and health implications. The objective of this study was to determine the ambient levels of polycyclic aromatic hydrocarbons

G. R. E. E. Ana; M. K. C. Sridhar; G. O. Emerole

2012-01-01

418

Fluorescence, Absorption, and Excitation Spectra of Polycyclic Aromatic Hydrocarbons as a Tool for Quantitative Analysis  

ERIC Educational Resources Information Center

A quantitative and qualitative study of the interplay between absorption, fluorescence, and excitation spectra of pollutants called polycyclic aromatic hydrocarbons (PAHs) is conducted. The study of five PAH displays the correlation of the above-mentioned properties along with the associated molecular changes.

Rivera-Figueroa, A. M.; Ramazan, K. A.; Finlayson-Pitts, B. J.

2004-01-01

419

REMOVAL OF POLYNUCLEAR AROMATIC HYDROCARBONS FROM PRIMARY ALUMINUM AIR POLLUTION CONTROL SCRUBBER WASTEWATER  

EPA Science Inventory

A pilot-scale study was conducted at a primary aluminum plant to evaluate the removal of benzo(a)pyrene and other polynuclear aromatic hydrocarbons (PAH's) from potline scrubber wastewater. Specific objectives included determining the need for granular activated carbon to remove ...

420

Exposure to polycyclic aromatic hydrocarbons (PAHs), mutagenic aldehydes and particulate matter during pan frying of beefsteak  

Microsoft Academic Search

ObjectivesCooking with gas or electric stoves produces fumes, especially during frying, that contain a range of harmful and potentially mutagenic compounds as well as high levels of fine and ultrafine particles. The aim of this study was to see if polycyclic aromatic hydrocarbons (PAHs) and higher mutagenic aldehydes which were collected in the breathing zone of the cook, could be

Ann Kristin Sjaastad; Rikke Bramming Jørgensen; Kristin Svendsen

2010-01-01

421

Coal-tar-based pavement sealcoat, polycyclic aromatic Hydrocarbons (PAHs), and environmental health  

USGS Publications Warehouse

Studies by the U.S. Geological Survey (USGS) have identified coal-tar-based sealcoat-the black, viscous liquid sprayed or painted on asphalt pavement such as parking lots-as a major source of polycyclic aromatic hydrocarbon (PAH) contamination in urban areas for large parts of the Nation. Several PAHs are suspected human carcinogens and are toxic to aquatic life.

Mahler, B.J.; Van Metre, P.C.

2011-01-01

422

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

Microsoft Academic Search

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

Robin J. Van Meter; James R. Spotila; Harold W. Avery

2006-01-01

423

FIELD COMPARISON OF POLYURETHANE FOAM AND XAD-2 RESIN FOR AIR SAMPLING FOR POLYNUCLEAR AROMATIC HYDROCARBONS  

EPA Science Inventory

A study of the sampling efficiency of two adsorbents, XAD-2 resin and polyurethane foam (PUF), for polynuclear aromatic hydrocarbons (PAH) in air, was performed under summer and winter ambient conditions. Two aspects were investigated: the collection efficiency for ambient PAH va...

424

EVALUATION OF HVS3 SAMPLER FOR SAMPLING POLYCYCLIC AROMATIC HYDROCARBONS AND POLYCHLORINATED BIPHENYLS  

EPA Science Inventory

A study was conducted to determine whether the High Volume Small Surface Sampler (HVS3) can quantitatively collect polycyclic aromatic hydrocarbons (PAH) will polychlorinated biphenyls (PCB) adsorbed onto house dust from nine houses in Seattle, Washington. In two of the houses, a...

425

Habitat function of agricultural soils as affected by heavy metals and polycyclic aromatic hydrocarbons contamination  

Microsoft Academic Search

Ecotoxic activity of soils polluted with polycyclic aromatic hydrocarbon (PAH) and heavy metals (HM) was evaluated in pot and laboratory experiments. Plants and soil microorganisms were chosen as test organisms and six different soil materials were used in the study. The applied levels of HM and PAH were aimed to reflect environmental conditions in the “worst case” situation. Zn2+, Pb2+

Barbara Maliszewska-Kordybach; Bo?ena Smreczak

2003-01-01

426

POLYCYCLIC AROMATIC HYDROCARBON BIODEGRADATION AS A FUNCTION OF OXYGEN TENSION IN CONTAMINATED SOIL  

EPA Science Inventory

Laboratory tests were conducted to determine the effect of soil gas oxygen concentration on the degradation and mineralization of spiked 14C-pyrene and nonspiked 16 priority pollutant polycyclic aromatic hydrocarbons (PAH) present in the soil. The soil used for the evaluation was...

427

THE EFFECT OF IRRADIANCE SPECTRA ON THE PHOTOACTIVATED TOXICITY OF THREE POLYCYCLIC AROMATIC HYDROCARBONS  

EPA Science Inventory

Photoinduced toxicity of polycyclic aromatic hydrocarbons (PAHs) is dependent on the concentration of compounds present and the dose of light recieved. Of the light present, only those wavelengths absorbed by the compound have the potential to initiate the photochemical events un...

428

EFFECT OF IRRADIANCE SPECTRA ON THE PHOTOINDUCED TOXICITY OF THREE POLYCYCLIC AROMATIC HYDROCARBONS  

EPA Science Inventory

Photoinduced toxicity of polycyclic aromatic hydrocarbons (PAHs) is dependent on the concentration of compounds present and the dose of light received. Of the light present, only those wavelengths absorbed by the compound have the potential to initiate the photochemical events un...

429

Spatial and temporal variability of particulate polycyclic aromatic hydrocarbons in Mexico City  

Microsoft Academic Search

As part of the Megacities Initiative: Local and Global Research Observations (MILAGRO) study in the Mexico City Metropolitan Area in March 2006, we mea- sured particulate polycyclic aromatic hydrocarbons (PAHs) and other gaseous species and particulate properties, includ- ing light absorbing carbon or effective black carbon (BC), at six locations throughout the city. The measurements were intended to support the

D. A. Thornhill; B. de Foy; S. C. Herndon; T. B. Onasch; E. C. Wood; M. Zavala; L. T. Molina; J. S. Gaffney; N. A. Marley; L. C. Marr

2008-01-01

430

Biodegradation of polycyclic aromatic hydrocarbons in sediments from the Daliao River watershed, China  

Microsoft Academic Search

The Daliao River, as an important water system in Northeast China, was reported to be heavily polluted by polycyclic aromatic hydrocarbons (PAHs). Aerobic biodegradations of four selected PAHs (naphthalene, phenanthrene, fluorene and anthracene) alone or in their mixture in river sediments from the Daliao River water systems were studied in microcosm systems. Effects of additional carbon source, inorganic nitrogen and

Xiangchun QUAN; Qian TANG; Mengchang HE; Zhifeng YANG; Chunye LIN; Wei GUO

2009-01-01

431

Phototoxic response of Lumbriculus variegatus to sediments contaminated by polycyclic aromatic hydrocarbons  

Microsoft Academic Search

The toxicity of certain polycyclic aromatic hydrocarbons (PAHs) to aquatic organisms can be greatly increased upon exposure of the organisms to ultraviolet (UV) radiation present in sunlight. The phenomenon of photoactivation of PAHs had received some attention in the laboratory; however, evaluation of the photoinduced toxicity of PAHs in field settings has been limited. In these studies, in situ chambers

Philip D. Monson; Gerald T. Ankley; Patricia A. Kosian

1995-01-01

432

Additive Toxicity of Binary Mixtures of Phototoxic Polycyclic Aromatic Hydrocarbons to the Oligochaete Lumbriculus variegatus  

Microsoft Academic Search

Toxicity of some polycyclic aromatic hydrocarbons (PAHs) can increase by an order of magnitude, or more, in the presence of solar ultraviolet (UV) radiation. In the environment, PAHs exist as complex mixtures, which generally would include multiple PAHs that could cause photoinduced toxicity. Hence, to accurately predict the potential ecological risk of phototoxic PAHs, it is critical to understand their

Russell J. Erickson; Gerald T. Ankley; David L. DeFoe; Patricia A. Kosian; Elizabeth A. Makynen

1999-01-01

433

Polycyclic aromatic hydrocarbons in soil and plant samples from the vicinity of an oil refinery  

Microsoft Academic Search

Soil samples, and samples of leaves of Plantago major (great plantain) and grass (mixed species) were collected from the vicinity of an oil refinery in Zelzate, Belgium, and analysed for seven polycyclic aromatic hydrocarbons (PAHs). The samples from the site adjacent to the refinery (site 1) contained very high total PAH-concentrations: namely 300, 8 and 2 ?g\\/g dry wt. for

Martine I. Bakker; Berta Casado; Judith W. Koerselman; Johannes Tolls; Chris Kollöffel

2000-01-01

434

Polycyclic Aromatic Hydrocarbons in stalagmites: Occurrence and use for analyzing past environments  

Microsoft Academic Search

This article presents a preliminary investigation into the value of Polycyclic Aromatic Hydrocarbons (PAHs) as markers for interpreting past environments in karst areas. We analyzed a core sample representing the last 400 years' growth from a massive stalagmite in the Chevaline Cave (Vercors, France), together with the soil overlying the karst directly above the stalagmite. During the last millennium, this area

Yves Perrette; Jérôme Poulenard; Abdel-Ilah Saber; Bernard Fanget; Sylvie Guittonneau; Bassam Ghaleb; Sandrine Garaudee

2008-01-01

435

Influence of volatility on the collection of polycyclic aromatic hydrocarbon vapors with polyurethane foam  

Microsoft Academic Search

Polycyclic aromatic hydrocarbon (PAH) vapor penetration through thin sections of polyurethane foam (PUF) was studied to determine the relationships between sample breakthrough, PAH vapor pressure, and total air volume. Frontal chromatographic movement of fluorene, phenanthrene, anthracene, and pyrene vapors through a PUF bed at high volume airflow was examined. From these fronts, the thickness of foam corresponding to 50% breakthrough

Feng You; Terry F. Bidleman

1984-01-01

436

Locally Aromatic Polycyclic Hydrocarbons as Potential Carriers of Infrared Emission Features  

NASA Astrophysics Data System (ADS)

We report B-LYP/6-31G* and B3-LYP/6-31G* density functional theory calculations on a set of polycyclic hydrocarbons, ranging in size from C19H22 to C36H32, combining aromatic (unsaturated) and aliphatic (saturated, sp3-hybridized carbon) ring systems. These locally aromatic polycyclic hydrocarbons (LAPHs), generally exhibiting large deviations from planarity, may be considered as intermediate structures between polycyclic aromatic hydrocarbons (PAHs) and nanodiamonds. Calculated infrared vibrational frequencies are found to be similar to those observed experimentally in spectra of hydrogenated amorphous carbon (HAC) and other carbonaceous solids. In the C-H stretching region (~3.1-3.6 ?m) these species are characterized by strong absorption/emission within both the aliphatic and aromatic C-H bands. They also show spectral features associated with tertiary C-H. Similar features are evident in calculated spectra of the corresponding ions, which we have characterized in some cases. Ionization results in the particular enhancement of a spectral feature typically seen at ~6.4 ?m, in the aromatic C-C stretching region. In keeping with previous experimental and theoretical studies on the spectra of neutral and cationic PAHs, we find that the influence of ionization on the relative intensities of C-C and C-H stretching features is much greater than the influence of molecular structure. We suggest that LAPHs may be significant contributors to emission in Type B unidentified infrared emission sources.

Petrie, Simon; Stranger, Robert; Duley, Walter W.

2003-09-01

437

Monocyclic aromatic hydrocarbons measured by differential optical absorption spectroscopy in urban areas (China)  

NASA Astrophysics Data System (ADS)

Monocyclic aromatic hydrocarbons are regarded as one of the most important classes of hydrocarbons in the atmosphere since they are a potential risk for human health and play a key role for photochemical smog formation. Differential Optical Absorption Spectroscopy (DOAS) has been widely used for many trace gases monitoring in the atmosphere however he analysis of aromatic compounds is difficult and the spectral structures from interfering absorbers (e.g. O2) should be very careful to separate correctly. This paper describes a spectral evaluation technique of aromatic compounds from DOAS measurement and summarizes the results of field measurements of benzene toluene xylene (BTX) in Chinese cities Beijing (2000) Shanghai (2001) and Hefei (2002). High concentrations of BTX were observed in Beijing and Shanghai whereas low concentrations in Hefei. This study will provide useful information to help understanding air pollution and atmospheric chemistry processes in urban areas ofChina and thereby contributes towards an improved pollution control strategy in Chinese cities.

Xie, Pinhua; Liu, Wenqing; Liu, Cheng; Yu, Yong; Volkerman, Rainer; Fu, Qiang; Mettendorf, Kai U.; Platt, Ulrich

2005-05-01

438

Environmental assessment of aromatic hydrocarbons-contaminated sediments of the Mexican Salina Cuz Bay.  

PubMed

Concentrations of total aromatic hydrocarbons and extractable organic matter in the water column and sediment were determined in samples collected in the course of the last 20 years from the Salina Cruz Harbor, México, to assess the degree of organic contamination. In sediments, organic compounds accumulate in shallow areas mostly associated with extractable organic matter and fine fractions. Calculated geocumulation index and enrichment factors suggest that contamination could be derived from anthropogenic activities attributed to harbor and ship scrapping activities, as well as transboundary source. Concentration of total aromatic hydrocarbons (as chrysene equivalents) ranged from 0.01 to 534 microg l(-1) in water, and from 0.10 to 2,160 microg g(-1) in sediments. Total aromatic concentration of 5 microg g(-1) is proposed as background concentration. PMID:17295107

González-Macías, C; Schifter, I; Lluch-Cota, D B; Méndez-Rodríguez, L; Hernández-Vázquez, S

2007-10-01

439

SPITZER'S VIEW ON AROMATIC AND ALIPHATIC HYDROCARBON EMISSION IN HERBIG Ae STARS  

SciTech Connect

The chemistry of astronomical hydrocarbons, responsible for the well-known infrared emission features detected in a wide variety of targets, remains enigmatic. Here we focus on the group of young intermediate-mass Herbig Ae stars. We have analyzed the aliphatic and polycyclic aromatic hydrocarbon (PAH) emission features in the infrared spectra of a sample of 53 Herbig Ae stars, obtained with the Infrared Spectrograph aboard the Spitzer Space Telescope. We confirm that the PAH-to-stellar luminosity ratio is higher in targets with a flared dust disk. However, a few sources with a flattened dust disk still show relatively strong PAH emission. Since PAH molecules trace the gas disk, this indicates that gas disks may still be flared, while the dust disk has settled due to grain growth. There are indications that the strength of the 11.3 {mu}m feature also depends on dust disk structure, with flattened disks being less bright in this feature. We confirm that the CC bond features at 6.2 and 7.8 {mu}m shift to redder wavelengths with decreasing stellar effective temperature. Moreover, we show that this redshift is accompanied by a relative increase of aliphatic CH emission and a decrease of the aromatic 8.6 {mu}m CH feature strength. Cool stars in our sample are surrounded by hydrocarbons with a high aliphatic/aromatic CH ratio and a low aromatic CH/CC ratio, and vice versa for the hot stars. We conclude that, while the overall hydrocarbon emission strength depends on the dust disk's geometry, the relative differences seen in the IR emission features in disks around Herbig Ae stars are mainly due to chemical differences of the hydrocarbon molecules induced by the stellar UV field. Strong UV flux reduces the aliphatic component and emphasizes the spectral signature of the aromatic molecules in the IR spectra.

Acke, B.; Waters, L. B. F. M. [Instituut voor Sterrenkunde, K.U. Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium); Bouwman, J.; Juhasz, A.; Henning, Th. [Max-Planck-Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany); Van den Ancker, M. E. [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching (Germany); Meeus, G. [Departamento de Fisica Teorica C-XV, Universidad Autonoma de Madrid, 28049 Madrid (Spain); Tielens, A. G. G. M., E-mail: bram@ster.kuleuven.b [Leiden Observatory, P.O. Box 9513, NL-2300 RA Leiden (Netherlands)

2010-07-20

440

Effect of three aromatic hydrocarbons on respiration and heart rates of the mussel, mytilus californianus  

SciTech Connect

The effects of petroleum derivatives on morality of marine invertebrates is now well established. Aromatics are considered to be the most toxic of all oil fractions. Recent studies of marine invertebrates have focused mainly upon respiration, locomotion, and growth. The filter feeding marine bivalves have received primary attention due to their proximity to coastal oil spills, importance in human food consumption and possible role in petroleum hydrocarbon bioconcentration. If these organisms are to be used as monitors in the future, then it is important to learn something of how quickly the bivalve responds metabolically to changes in ambient levels of petroleum hydrocarbons. Respiration and heart activity reveal a great deal of information concerning the physiological state of the bivalve. We report measrements of these two variables in the mussel, Mytilus californianus (Conrad), under conditions of exposure to, and recovery from, three aromatic hydrocarbons.

Sabourin, T.D.; Tullis, R.E.

1981-06-01

441

HETEROGENEOUS PHOTOCATALYTIC DECOMPOSITION OF POLY- AROMATIC HYDROCARBONS OVER TITANIUM DIOXIDE  

EPA Science Inventory

The photocatalytic degradation of a mixture of 16 polyaromatic hydrocarbons (PAHs) was investigated in aqueous suspensions of high surface area TiO2 illuminated with 310?380 nm ultraviolet light. Triethylamine was utilized for extraction of PAH compounds from motor oil...

442

Aromatic as well as aliphatic hydrocarbon solvent axonopathy.  

PubMed

Superfund sites that contain mixtures of aromatic and aliphatic solvents represent an undefined health hazard. After prolonged exposure to relatively high levels of certain aliphatic solvents (e.g. n-hexane, 2-hexanone), humans and animals develop a dose-dependent neurodegeneration that occurs clinically as a symmetrical peripheral neuropathy. This is triggered by the action of 2,5-hexanedione (1,2-diacetylethane), a 1,4-diketone (gamma-diketone) metabolite that targets proteins required for the maintenance of neuronal (and testicular Sertoli cell) integrity. Certain aromatic solvents (1,2-diethylbenzene, 1,2,4-triethylbenzene) cause electrophysiological changes consistent with sensorimotor neuropathy in rodents, but the underlying mechanisms and pathogenesis are unclear. Our recent studies show that the o-diacetyl derivative and likely metabolite of 1,2-diethylbenzene, 1,2-diacetylbenzene, behaves as a neurotoxic (aromatic) gamma-diketone of high neurotoxic potency. Rats treated with 1,2-diacetylbenzene develop limb weakness associated with proximal, neurofilament-filled giant axonal swellings comparable to those seen in animals treated with the potent 3,4-dimethyl derivative of 2,5-hexanedione. The blue chromogen induced by treatment with 1,2-diacetylbenzene is under study as a possible urinary biomarker of exposure to aromatic solvents (e.g. 1,2-diethylbenzene, tetralin) with neurotoxic potential. Development and validation of sensitive new biomarkers, especially for non-cancer endpoints, will aid in assessing the health risk associated with exposure to hazardous substances at Superfund sites. PMID:12018006

Spencer, Peter S; Kim, Min Sun; Sabri, Mohammad I

2002-03-01

443

Measurements of Methylglyoxal and Aromatic Hydrocarbons during 06 MILAGRO Campaign  

Microsoft Academic Search

Methylglyoxal (CH3COCHO) is produced in the atmosphere from photochemical oxidation of volatile organic compounds (VOCs). Oxidation of anthropogenic aromatics (toluene, xylenes, or trimethylbenzenes) and biogenic isoprene leads to a significant production of methylglyoxal in the urban and regional atmospheres. For example, the molar molecular yield of methylglyoxal is about 0.9 from 1,3,5-trimethylbenzene oxidation and 0.4 to 0.16 for toluene oxidation.

E. Fortner; J. Zheng; R. Zhang; L. Molina

2007-01-01

444

Stabilization of bound polycyclic aromatic hydrocarbons by a pi-cation interaction.  

PubMed

Proteins can use aromatic side-chains to stabilize bound cationic ligands through cation-pi interactions. Here, we report the first example of the reciprocal process, termed pi-cation, in which a cationic protein side-chain stabilizes a neutral aromatic ligand. Site-directed mutagenesis revealed that an arginine side-chain located in the deep binding pocket of a monoclonal antibody (4D5) is essential for binding the neutral polynuclear aromatic hydrocarbon benzo[a]pyrene. This Arg was very likely selected for in the primary response, further underscoring the importance of the pi-cation interaction for ligand binding, which should be considered in protein analysis and design when ligands include aromatic groups. PMID:10986127

Pellequer, J L; Zhao, B; Kao, H I; Bell, C W; Li, K; Li, Q X; Karu, A E; Roberts, V A

2000-09-22

445

Aliphatic and polycyclic aromatic hydrocarbons in Black Sea sediments  

Microsoft Academic Search

Concentrations of aliphatic hydrocarbons (AHC) in sediments of the Black Sea ranged from 153,000 ng g?1 dw near the mouth of the Danube River to about 10,000 ng g?1 dw in abyssal plain sediments. Compound distributions were dominated by long-chain n-alkanes except at the Danube station where a significant petrogenic component with an unresolved complex mixture was also present. Polycyclic

Stuart G. Wakeham

1996-01-01

446

Blockade of the aryl hydrocarbon receptor pathway triggered by dioxin, polycyclic aromatic hydrocarbons and cigarette smoke by Phellinus linteus.  

PubMed

Environmental pollutants including halogenated and polycyclic aromatic hydrocarbons activate the aryl hydrocarbon receptor (AhR) and thereby cause a wide range of pathological changes. Development of AhR antagonists will be useful for prevention and treatment of diseases related to AhR activation. Towards this end, we aimed in the present study at seeking for potential inhibitors of the AhR pathway in mycelial extracts using the dioxin responsive element-based sensing via secreted alkaline phosphatase (DRESSA). Through the screening of 13 mycelia, extracts prepared from Phellinus linteus, Cordyceps militaris and Hericium erinaceum inhibited activation of AhR by 2,3,7,8-tetrachlorodibenzo-p-dioxin, benzo[a]pyrene or 3-methylcholanthrene. Subsequent studies revealed that only Phellinus linteus suppressed activation of AhR and AhR-dependent gene expression triggered by all of these agonists. Cigarette smoke is known to contain a number of halogenated and polycyclic aromatic hydrocarbons. We found that Phellinus linteus has the potential to block activation of AhR and AhR-dependent gene expression triggered by cigarette smoke. Furthermore, the inhibitory effect of Phellinus linteus on the AhR pathway was independent of; 1) depression of AhR or AhR nuclear translocator, and 2) induction of AhR repressor. We conclude that Phellinus linteus contains potent inhibitor(s) of AhR activation and may be useful for prevention of pathologies associated with aberrant activation of AhR. PMID:18827349

Mukai, Mai; Kasai, Ayumi; Hiramatsu, Nobuhiko; Hayakawa, Kunihiro; Okamura, Maro; Tagawa, Yasuhiro; Yao, Jian; Nakamura, Tomoyuki; Kitamura, Masanori

2008-10-01

447

Polycyclic Aromatic Hydrocarbon Degradation of Phytoplankton-Associated Arenibacter spp. and Description of Arenibacter algicola sp. nov., an Aromatic Hydrocarbon-Degrading Bacterium  

PubMed Central

Pyrosequencing of the bacterial community associated with a cosmopolitan marine diatom during enrichment with crude oil revealed several Arenibacter phylotypes, of which one (OTU-202) had become significantly enriched by the oil. Since members of the genus Arenibacter have not been previously shown to degrade hydrocarbons, we attempted to isolate a representative strain of this genus in order to directly investigate its hydrocarbon-degrading potential. Based on 16S rRNA sequencing, one isolate (designated strain TG409T) exhibited >99% sequence identity to three type strains of this genus. On the basis of phenotypic and genotypic characteristics, strain TG409T represents a novel species in the genus Arenibacter, for which the name Arenibacter algicola sp. nov. is proposed. We reveal for the first time that polycyclic aromatic hydrocarbon (PAH) degradation is a shared phenotype among members of this genus, indicating that it could be used as a taxonomic marker for this genus. Kinetic data for PAH mineralization rates showed that naphthalene was preferred to phenanthrene, and its mineralization was significantly enhanced in the presence of glass wool (a surrogate for diatom cell surfaces). During enrichment on hydrocarbons, strain TG409T emulsified n-tetradecane and crude oil, and cells were found to be preferentially attached to oil droplets, indicating an ability by the strain to express cell surface amphiphilic substances (biosurfactants or bioemulsifiers) as a possible strategy to increase the bioavailability of hydrocarbons. This work adds to our growing knowledge on the diversity of bacterial genera in the ocean contributing to the degradation of oil contaminants and of hydrocarbon-degrading bacteria found living in association with marine eukaryotic phytoplankton.

Rhodes, Glenn; Mishamandani, Sara; Berry, David; Whitman, William B.; Nichols, Peter D.; Semple, Kirk T.; Aitken, Michael D.

2014-01-01

448

Detection of aromatic hydrocarbons in the atmosphere at ppt levels  

NASA Astrophysics Data System (ADS)

A new method has been described and evaluated which will detect ppt levels of hydrocarbons in the atmosphere. An automatic GC was used with a concentrator and a photoionization detector to measure benzene, toluene and xylene. The values obtained in the Boston, MA area were in good agreement with the literature value. The BTX data were compared with simultaneous CO 2 data and some interesting features were observed. Good correlation was obtained with simultaneous CO 2 data during rush hour traffic and no correlation during the early morning hours when the BTX values would rise while the CO 2 values decreased to their ambient levels of 350 ppm.

Whalen, M.; Driscoll, J. N.; Wood, C. D.

449

Determination of low concentrations of aromatic hydrocarbons in multicomponent mixtures with iso-octane and n-heptane  

NASA Astrophysics Data System (ADS)

We have experimentally studied the absorption spectra of hydrocarbon mixtures based on n-heptane and isooctane with small (1%-2%) additions of aromatic hydrocarbons (benzene, toluene, xylene). The study was conducted in the region of the first overtones of the vibrational spectra for the hydrocarbon groups CH3, CH2, CH. We show that four-component modeling of the absorption spectrum of the hydrocarbon mixture and minimization of the deviation of the model spectrum from the experimental spectrum allow us to separately determine the content of the aromatic additives for concentrations from 1%.

Vesnin, V. L.; Muradov, V. G.

2011-11-01

450

Polycyclic aromatic hydrocarbon formation in carbon-rich stellar envelopes  

NASA Technical Reports Server (NTRS)

A detailed chemical kinetic scheme is applied to stellar envelope profiles of gas density and temperature profiles in order to study the formation of PAH molecules in carbon-rich stellar outflows. Chemical concentration profiles are calculated for several envelope models by integrating the coupled continuity equations that include spherically expanding flows from an inner boundary at the shock formation radius. The influence of the 'inverse greenhouse' effect experienced by small PAHs is investigated and shown to increase the PAH yield by many orders of magnitude. It is shown that the route through propargyl radicals could be an important channel to produce benzene. PAH formation yields are found to be extremely sensitive to gas density and temperature and are much smaller than values inferred from the observed dust content of late-type carbon-rich stellar envelopes. It is therefore unlikely that aromatic molecules are generated in the stellar outflow itself.

Cherchneff, Isabelle; Barker, John R.; Tielens, Alexander G. G. M.

1992-01-01

451

TRENDS OF POLYCYCLIC AROMATIC HYDROCARBON LEVELS AND MUTAGENICITY IN SANTIAGO'S INHALABLE AIRBORNE PARTICLES IN THE PERIOD 1992-1996.  

EPA Science Inventory

Abstract Trends of polycyclic aromatic hydrocarbons (PAHs) for 1992-1996 (cold season) and their mutagenic activity were investigated in organic extracts from the Santiago. Chile. inhalable particles (PM10). The highest PAH concentrations were observed in 1992 and decline...

452

BROMO- AND BROMOCHLORO-POLYNUCLEAR AROMATIC HYDROCARBONS, DIOXINS AND DIBENZOFURANS IN MUNICIPAL INCINERATOR FLY ASH (JOURNAL VERSION)  

EPA Science Inventory

A fly ash sample found to contain polychlorinated dioxins and dibenzofurans was analyzed for brominated analytes. Bromochloro-polynuclear aromatic hydrocarbons, dioxins and dibenzofurans, as well as bromo PAH were found in ppt to ppb concentrations. Analytical results were confir...

453

IMPORTANCE OF BLACK CARBON IN DISTRIBUTION AND BIOACCUMULATION MODELS OF POLYCYCLIC AROMATIC HYDROCARBONS IN CONTAMINATED MARINE SEDIMENTS  

EPA Science Inventory

The roles and relative importance of nonpyrogenic organic carbon (NPOC) and black carbon (BC) as binding phases of polycyclic aromatic hydrocarbons (PAHs) were assessed by their ability to estimate pore water concentrations and biological uptake in various marine sediments. Sedim...

454

SYNTHESIS AND BIOLOGICAL ACTIVITY OF CYCLOPENTA EPOXIDES OF PAH (POLYCYCLIC AROMATIC HYDROCARBONS) CONTAINING PERIPHERALLY FUSED CYCLOPENTA RINGS  

EPA Science Inventory

Polycyclic aromatic hydrocarbons (PAH) containing peripherally fused cyclopenta rings have been identified in soots from many different combustion sources. Metabolism and mutagenicity studies have been reported on the series of four cyclopenta-fused isomers derived from benzanthr...

455

PILOT-SCALE SUBCRITICAL WATER REMEDIATION OF POLYCYCLIC AROMATIC HYDROCARBON- AND PESTICIDE-CONTAMINATED SOIL. (R825394)  

EPA Science Inventory

Subcritical water (hot water under enough pressure to maintain the liquid state) was used to remove polycyclic aromatic hydrocarbons (PAHs) and pesticides from highly contaminated soils. Laboratory-scale (8 g of soil) experiments were used to determine conditions f...

456

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

EPA Science Inventory

The generation by combustion processes of airborne species of current health concern such as polycyclic aromatic hydrocarbons (PAH) and soot particles necessitates a detailed understanding of chemical reaction pathways responsible for their formation. The present review discus...

457

PHOTOACTIVATED POLYCYCLIC AROMATIC HYDROCARBON TOXICITY IN MEDAKA (ORYZIAS LATIPES) EMBRYOS: RELEVANCE TO ENVIRONMENTAL RISK IN CONTAMINATED SITES  

EPA Science Inventory

The hazard for photoactivated toxicity of polycyclic aromatic hydrocarbons (PAHs) has been clearly demonstrated; however, to our knowledge, the risk in contaminated systems has not been characterized. To address this question, a median lethal dose (LD50) for fluoranthene photoa...

458

Determination of Semivolatile Organic Compounds and Polycyclic Aromatic Hydrocarbons in Solids by Gas Chromatography/Mass Spectrometry.  

National Technical Information Service (NTIS)

A method for the determination of 38 polycyclic aromatic hydrocarbons (PAHs) and semivolatile organic compounds in solid samples is described. Samples are extracted using a pressurized solvent extraction system. The compounds of interest are extracted fro...

S. D. Zaugg M. R. Burkhardt T. L. Burbank M. C. Olson J. L. Iverson M. P. Schroeder

2006-01-01

459

COMPARISON OF IMMUNOASSAY AND GAS CHROMATOGRAPHY/MASS SPECTROMETRY FOR MEASUREMENT OF POLYCYCLIC AROMATIC HYDROCARBONS IN CONTAMINATED SOIL  

EPA Science Inventory

Polycyclic aromatic hydrocarbons (PAHs) are frequently encountered in the environment and may pose health concerns due to their carcinogenicity. A commercial enzyme-linked immunosorbent assay (ELISA), was evaluated as a screening method for monitoring PAHs at contaminated site...

460

AVAILABILITY OF PCBS (POLYCHLORINATED BIPHENYLS) AND PAHS (POLYCYCLIC AROMATIC HYDROCARBONS) TO 'MYTILUJ EDULIS' FROM ARTIFICIALLY RESUSPENDED SEDIMENTS  

EPA Science Inventory

Estuarine sediment containing high levels of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) was resuspended into a flowing seawater system. Analysis of the dissolved and particulate phases in the exposure tank indicated a release of some low molecula...

461

Characterization of subsurface polycyclic aromatic hydrocarbons at the Deepwater Horizon site  

NASA Astrophysics Data System (ADS)

Here, we report the initial observations of distributions of polycyclic aromatic hydrocarbons (PAH) in subsurface waters near the Deepwater Horizon oil well site (also referred to as the Macondo, Mississippi Canyon Block 252 or MC252 well). Profiles of in situ fluorescence and beam attenuation conducted during 9-16 May 2010 were characterized by distinct peaks at depths greater than 1000 m, with highest intensities close to the wellhead and decreasing intensities with increasing distance from the wellhead. Gas chromatography/mass spectrometry (GC/MS) analyses of water samples coinciding with the deep fluorescence and beam attenuation anomalies confirmed the presence of polycyclic aromatic hydrocarbons (PAH) at concentrations reaching 189 ?g L-1 (ppb). Subsurface exposure to PAH at levels considered to be toxic to marine organisms would have occurred in discrete depth layers between 1000 and 1400 m in the region southwest of the wellhead site and extending at least as far as 13 km.

Diercks, Arne-R.; Highsmith, Raymond C.; Asper, Vernon L.; Joung, DongJoo; Zhou, Zhengzhen; Guo, Laodong; Shiller, Alan M.; Joye, Samantha B.; Teske, Andreas P.; Guinasso, Norman; Wade, Terry L.; Lohrenz, Steven E.

2010-10-01

462

Renal cancer risk and occupational exposure to polycyclic aromatic hydrocarbons and plastics  

PubMed Central

Objective To investigate whether occupational exposure to polycyclic aromatic hydrocarbons and certain plastic monomers increased renal cell carcinomas (RCC) risk. Methods Unconditional logistic regression was used to calculate RCC risk in relation to exposure. Results No association between RCC risk and having ever been occupationally exposed to any polycyclic aromatic hydrocarbons or plastics was observed. Duration of exposure and average exposure also showed no association with risk. Suggestive positive associations between RCC risk and cumulative exposure to styrene (P-trend = 0.02) and acrylonitrile (P-trend = 0.06) were found. Cumulative exposure to petroleum/gasoline engine emissions was inversely associated with risk (P-trend = 0.02). Conclusions Results indicate a possible association between occupational styrene and acrylonitrile exposure and RCC risk. Additional studies are needed to replicate findings, as this is the first time these associations have been reported and they may be due to chance.

Karami, Sara; Boffetta, Paolo; Brennan, Paul; Stewart, Patricia A.; Zaridze, David; Matveev, Vsevolod; Janout, Vladimir; Kollarova, Helena; Bencko, Vladimir; Navratilova, Marie; Szeszenia-Dabrowska, Neonila; Mates, Dana; Gromiec, Jan P.; Sobotka, Roman; Chow, Wong-Ho; Rothman, Nathaniel; Moore, Lee E.

2011-01-01

463

Production of aromatic hydrocarbons through catalytic pyrolysis of ?-valerolactone from biomass.  

PubMed

In the present study, ?-valerolactone (GVL) is firstly reported to be converted into aromatic hydrocarbons through catalytic pyrolysis. The catalysts and reaction conditions are both critical in maximizing the hydrocarbon selectivity. Four zeolites, i.e. MCM-41, ?-zeolite, ZSM-5 and HZSM-5 were tested in this work, among which HZSM-5 (Si/Al=25) was found to be the most effective catalyst in both reactivity and selectivity. Under the reaction temperature of 500 °C, the highest carbon yield of 56.71% of aromatics was achieved from GVL with HZSM-5 (Si/Al=25) as catalyst. Moreover, the HZSM-5 catalyst was recycled for five times without significant decrease in product selectivity. PMID:22507905

Zhao, Yan; Fu, Yao; Guo, Qing-Xiang

2012-06-01

464

Solubility of organic compounds in nonaqueous systems; Polycyclic aromatic hydrocarbons in benzene  

SciTech Connect

The present paper deals with the evaluation of some widely used models used to calculate activity coefficients and the assumptions for the ideal solubility for some polycyclic aromatic hydrocarbons in benzene. The results show that, for ideal solubility, {Delta}C{sub p} {approx} 0 is a better approximation than {Delta}C{sub p} {approx} {Delta}S{sub f}. The values obtained for the entropic activity coefficients are similar from both UNIFAC and Flory-Huggins theories. The residual activity coefficients calculated from Scatchard-Hildebrand theory and UNIFAC are, however, very different. The combination of Flory-Huggins and Scatchard-Hildebrand theories gives better predictions for the solubility of polycyclic aromatic hydrocarbons in benzene than does UNIFAC theory.

Mishra, D.S.; Yalkowsky, S.H. (Dept. of Pharmaceutical Sciences, College of Pharmacy, Univ. of Arizona, Tuscon, AZ (US))

1990-11-01

465

Hydrogen transfer reaction in polycyclic aromatic hydrocarbon radicals.  

PubMed

Density functional theory calculations have been successfully applied to investigate the formation of hydrocarbon radicals and hydrogen transfer pathways related to the chemical vapor infiltration process based on model molecules of phenanthrene, anthra[2,1,9,8-opqra]tetracene, dibenzo[a,ghi]perylene, benzo[uv]naphtho[2,1,8,7-defg]pentaphene, and dibenzo[bc,ef]ovalene. The hydrogen transfer reaction rate constants are calculated within the framework of the Rice-Ramsperger-Kassel-Marcus theory and the transition state theory by use of the density functional theory calculation results as input. From these calculations, it is concluded that the hydrogen transfer reaction between two bay sites can happen almost spontaneously with energy barrier as low as about 4.0 kcal mol(-1), and the hydrogen transfer reactions between two armchair sites possess lower energy barrier than those between two zigzag sites. PMID:24893119

Liu, Huiting; Yan, Liuming; Yue, Baohua; Li, Aijun

2014-06-26

466

Assessment of polycyclic aromatic hydrocarbon input to urban wetlands in relation to adjacent land use  

Microsoft Academic Search

The relationship between polycyclic aromatic hydrocarbons (PAHs) in wetland surface sediments and adjacent land use was assessed in the Elizabeth River, VA, an urbanized sub-estuary of the Chesapeake Bay. Significant differences (p<0.05) in surface sediment PAH concentration between sites indicated adjacent land use had a substantial influence on PAH concentration in wetland sediments. Wetlands adjacent to parking lots and petroleum

K. L. Kimbrough; R. M. Dickhut

2006-01-01

467

Black carbon and polycyclic aromatic hydrocarbons (PAHs) in surface sediments of China’s marginal seas  

Microsoft Academic Search

This study investigates the distribution of black carbon (BC) and its correlation with total polycyclic aromatic hydrocarbons\\u000a (?PAH) in the surface sediments of China’s marginal seas. BC content ranges from <0.10 to 2.45 mg\\/g dw (grams dry weight)\\u000a in the sediments studied, and varied among the different coastal regions. The Bohai Bay sediments had the highest BC contents\\u000a (average 2.18

Yanju Kang; Xuchen Wang; Minhan Dai; Huan Feng; Anchun Li; Qian Song

2009-01-01

468

Altered Tissue Levels of Vitamin a by Selected Polycyclic Aromatic Hydrocarbons (PAHs)  

Microsoft Academic Search

The purpose of this study was to determine the effects of certain polycyclic aromatic hydrocarbons (PAHs) of known carcinogenic potential on rat tissue levels of retinol and retinyl esters. Male Sprague-Dawley rats fed a vitamin A-adequate diet (1.3 mg of retinyl palmitate\\/kg) for 30 days were intraperitoneally administered three injections of one of the following four PAHs: carcinogenic 3-methylcholanthrene (MC),

Li-Chuan Chen; Isabelle Berberian; Howard P. Glauert; Larry W. Robertson; Ching K. Chow

1994-01-01