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Sample records for aromatic hydrocarbons indoor

  1. Source apportionment of polycyclic aromatic hydrocarbons and their derivatives in indoor air

    SciTech Connect

    Ray, B.; Mitra, S.

    1996-12-31

    The average person spends more than 80% of his time indoors, thus analysis of the sources of airborne pollutants in indoor air is an important issue. In this paper, we use factor analysis and multiple regression to identify and apportion the different sources of select indoor polycyclic aromatic hydrocarbons (PAHs), their derivatives, and nicotine in indoor air, using data gathered in eight homes in Columbus, OH during the winter of 1986/1987. These homes had different indoor PAH sources, namely, environmental tobacco smoke, gas cooking/heating, and electrical cooking stoves. We find that, of all the sources, environmental tobacco smoke appears to have the greatest impact on the total indoor PAH concentrations. In smokers` homes, more than 87% of the total PAH is due to this source. Background sources are the largest contributor to PAHs in nonsmokers` homes. Very little PAH can be attributed to gas or electric appliances in the home. 16 refs., 3 tabs.

  2. The contribution of traffic to indoor concentrations of polycyclic aromatic hydrocarbons.

    PubMed

    Dubowsky, S D; Wallace, L A; Buckley, T J

    1999-01-01

    A photoelectric aerosol sensor (PAS) was used to measure real-time indoor concentrations of polycyclic aromatic hydrocarbons (PAHs) at three residences. Semi-quantitative measurements of total indoor particle-bound PAH and temperature were collected continuously every minute for approximately 2 weeks at each location. The purpose of this study was to examine the effect of traffic on indoor concentrations of PAHs. This was accomplished by collecting indoor measurements at an urban, semi-urban, and suburban residential location with varying levels of, and proximity to, traffic. Since the homes were occupied, the effects of cooking, the dominant indoor source, were also examined among the three nonsmoking households. The results indicate that traffic was the main outdoor source of PAH concentrations measured indoors for all locations. In fact, a significant (p<0.001) traffic-related trend in weekday PAH concentration was detected with a geometric mean concentration at the urban location (31 ng/m3) nearly two times that at the semi-urban location (19 ng/m3) and over three times larger than the suburban location (8.0 ng/m3), once adjusted for indoor sources. Hourly average concentration profiles also revealed weekday rush hour peaks of PAHs at all locations. No pronounced peaks and significantly lower concentrations (10, 10, and 4.9 ng/m3) were seen during the weekends for all locations i.e., the urban, semi-urban and suburban locations, respectively. Indoor sources including frying/sautéing, broiling, and candle-burning were characterized by peak concentration, duration of PAH elevation, and potential dose. This analysis suggests that cooking, and especially frying/sautéing, may be an important source of indoor PAH concentrations. PMID:10489156

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

    PubMed

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

    2014-09-01

    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 μg/g to 470 μg/g with a mean value of 30.9 μg/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

  4. Patterns and sources of polycyclic aromatic hydrocarbons and their derivatives in indoor air

    NASA Astrophysics Data System (ADS)

    Mitra, Somenath; Ray, Bonnie

    Select polycyclic aromatic hydrocarbons (PAHs), their derivatives, and nicotine were measured in eight homes in Columbus, Ohio, during the winter of 1986/1987 by Chuang et al. (1988, Technical Report EPA/600/4-28/028, U.S. EPA). These homes had different indoor PAH sources, namely, environmental tobacco smoke, gas cooking/heating, and electrical cooking stoves. We use a combination of correlation analysis, factor analysis and multiple regression to identify and apportion the different sources of PAHs. We find that, of all the sources, environmental tobacco smoke appears to have the greatest impact on the total indoor PAH concentrations. In smokers' homes, more than 87% of the total PAH is due to this source. Background sources are the largest contributor to PAHs in nonsmokers' homes. We also study the source apportionment of total extractable organic material (EOM) measured in the homes. In smokers' homes, EOM can be attributed mainly to environmental tobacco smoke (49%) and background sources (42%).

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

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

  6. 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...

  7. Emission of Oxygenated Polycyclic Aromatic Hydrocarbons from Indoor Solid Fuel Combustion

    PubMed Central

    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.

    2011-01-01

    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 (EFOPAH) 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 EFOPAH ranged from 2.80.2 to 8.12.2 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 EFOPAH 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, Ro, 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 Ro values were 0.16 ~ 0.89 for crop residues and 0.03 ~ 0.25 for coals. Ro 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

  8. Residual indoor contamination from world trade center rubble fires as indicated by polycyclic aromatic hydrocarbon profiles.

    PubMed

    Pleil, Joachim D; Funk, William E; Rappaport, Stephen M

    2006-02-15

    The catastrophic destruction of the World Trade Center (WTC) on Sept. 11, 2001 (9/11) created an immense dust cloud followed by fires that emitted smoke and soot into the air of New York City (NYC) well into December. Outdoor pollutant levels in lower Manhattan returned to urban background levels after about 200 days as the fires were put out and the debris cleanup was completed. However, particulate matter (PM) from the original collapse and fires also penetrated into commercial and residential buildings. This has created public concern because WTC dust is thought to cause adverse pulmonary symptoms including "WTC cough" and reduced lung capacity. Additionally, some recent studies have suggested a possible link between exposure to WTC contamination and other adverse health effects. Distinguishing between normal urban pollutant infiltration and residual WTC dust remaining in interior spaces is difficult; efforts are underway to develop such discriminator methods. Some progress has been made in identifying WTC dust by the content of fibers believed to be associated with the initial building collapse. There are also contaminants created by the fires that burned for 100 days in the debris piles of the building rubble. Using WTC ambient air samples, we have developed indicators for fire related PM based on the relative amounts of specific particle bound polycyclic aromatic hydrocarbons (PAHs) and the mass fraction of PAHs per mass of PM. These two parameters are combined, and we show a graphical method for discriminating between fire sources and urban particulate sources as applied to samples of settled dusts. We found that our PAHs based discriminator method can distinguish fire source contributions to WTC related particulate matter and dusts. Other major building fires or large open burn events could have similar PAHs characteristics. We found that random samples collected approximately 3.5 years after the WTC event from occupied indoor spaces (primarily residential) in the New York area are not statistically distinguishable from contemporary city background. PMID:16572771

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

    PubMed

    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

    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 μm for crop residues and high caking coals and <0.7 μm for the tested low caking briquettes. PMID:21375317

  10. Aromatic hydrocarbons in the atmospheric environment - Part II: univariate and multivariate analysis and case studies of indoor concentrations

    NASA Astrophysics Data System (ADS)

    Ilgen, Elke; Levsen, Karsten; Angerer, Jürgen; Schneider, Peter; Heinrich, Joachim; Wichmann, H.-Erich

    The concentrations of the aromatic hydrocarbons benzene, toluene, ethylbenzene and the isomeric xylenes (BTEX) have been determined in the indoor air of 115 private non-smoker homes (˜380 individual rooms) situated in areas with an extreme traffic situation, i.e. in city streets (street canyons) with high traffic density and in rural areas with hardly any traffic at all. The influence of the traffic on the indoor concentration was apparent in the high traffic area. In order to identify other factors influencing the BTEX concentrations, the data and additional questionnaires were analyzed by univariate and multivariate analysis. The analysis was supplemented by some case studies. It is shown that meteorology (the seasons), the type of room (e.g. living room versus bedroom), the ventilation and, in particular, garages in the house strongly influence the indoor concentration of BTEX. Thus, the indoor BTEX level is significantly higher in winter than in summer. Moreover, garages with a connecting door to the living quarters lead to high indoor concentrations of aromatic hydrocarbons in these rooms. In addition, the storage of solvents and hobby materials, and also the presence of smoking guests increase the BTEX level. If rooms are directly heated by coal or wood, the BTEX level is higher compared to the use of gas heating. Surprisingly, no correlation was found between the building materials used and the BTEX level. Case studies were carried out for two homes with an integrated garage (and a connecting door to the living rooms) and for seven homes where redecoration work was carried out during sampling. In both instances, a pronounced increase was observed in the BTEX concentration.

  11. Spatiotemporal analysis and human exposure assessment on polycyclic aromatic hydrocarbons in indoor air, settled house dust, and diet: A review.

    PubMed

    Ma, Yuning; Harrad, Stuart

    2015-11-01

    This review summarizes the published literature on the presence of polycyclic aromatic hydrocarbons (PAH) in indoor air, settled house dust, and food, and highlights geographical and temporal trends in indoor PAH contamination. In both indoor air and dust, ΣPAH concentrations in North America have decreased over the past 30 years with a halving time of 6.7±1.9years in indoor air and 5.0±2.3 years in indoor dust. In contrast, indoor PAH concentrations in Asia have remained steady. Concentrations of ΣPAH in indoor air are significantly (p<0.01) higher in Asia than North America. In studies recording both vapor and particulate phases, the global average concentration in indoor air of ΣPAH excluding naphthalene is between 7 and 14,300 ng/m(3). Over a similar period, the average ΣPAH concentration in house dust ranges between 127 to 115,817ng/g. Indoor/outdoor ratios of atmospheric concentrations of ΣPAH have declined globally with a half-life of 6.3±2.3 years. While indoor/outdoor ratios for benzo[a]pyrene toxicity equivalents (BaPeq) declined in North America with a half-life of 12.2±3.2 years, no significant decline was observed when data from all regions were considered. Comparison of the global database, revealed that I/O ratios for ΣPAH (average=4.3±1.3), exceeded significantly those of BaPeq (average=1.7±0.4) in the same samples. The significant decline in global I/O ratios suggests that indoor sources of PAH have been controlled more effectively than outdoor sources. Moreover, the significantly higher I/O ratios for ΣPAH compared to BaPeq, imply that indoor sources of PAH emit proportionally more of the less carcinogenic PAH than outdoor sources. Dietary exposure to PAH ranges from 137 to 55,000 ng/day. Definitive spatiotemporal trends in dietary exposure were precluded due to relatively small number of relevant studies. However, although reported in only one study, PAH concentrations in Chinese diets exceeded those in diet from other parts of the world, a pattern consistent with the spatial trends observed for concentrations of PAH in indoor air. Evaluation of human exposure to ΣPAH via inhalation, dust and diet ingestion, suggests that while intake via diet and inhalation exceeds that via dust ingestion; all three pathways contribute and merit continued assessment. PMID:26197059

  12. Source Attribution of Personal Exposure to Airborne Polycyclic Aromatic Hydrocarbon Mixture Using Concurrent Personal, Indoor, and Outdoor Measurements

    PubMed Central

    Choi, Hyunok; Spengler, John

    2014-01-01

    Objectives Relative importance of multiple indoor and outdoor venues on personal exposure concentrations to pro-carcinogenic polycyclic aromatic hydrocarbons (c-PAHs) remains poorly understood. This is particularly challenging because many c-PAHs share sources and occur as a complex mixture. Accurate and precise apportionment of personal exposure according to exposure venues could aid in understanding of human health effects due to given source. Here, we partitioned indoor and personal exposure concentrations to seven c-PAHs and pyrene according to the indoor- and outdoor- origins. Methods A simultaneous, integrated monitoring of personal, indoor and outdoor concentrations of nine PAHs was conducted in 75 homes for a consecutive 48-hour period across a two-year period in Kraków, Poland. Due to few known indoor sources for chrysene, we used this PAH species as a tracer for infiltration of outdoor PAHs. Personal and indoor concentrations of seven c-PAHs and pyrene were apportioned to home indoor, non-home indoor and outdoor origin. Results Using Chrysenein / Chryseneout as proxy for an infiltration factor, Finf, infiltrated PAHs of outdoor origin are overall higher in concentration than those emitted from the indoor origin. Average contribution by the outdoor sources on B[a]A, B[b]F, and B[k]F were 92%, 79%, and 78% across all seasons. In contrast, in homes where a household members smoked, average contribution by the outdoor sources on B[ghi]P, B[a]P, D[ah]A, and IP were lower (i.e., 67%, 65%, 67%, and 66%, respectively). Season-averaged contribution by the outdoor sources on personal exposure to B[a]A, B[b]F, and B[k]F were 92%, 74%, and 77%, respectively. On the other hand, season-averaged home indoor source contribution on personal exposure to B[a]A, B[b]F, and B[k]F were estimated at 6%, 15%, and 19%, respectively. Similar contributions by season-averaged home indoor sources on personal exposure were estimated at 28% for B[ghi]P, 31% for B[a]P, 25% for D[ah]A, and 28% for IP. Conclusion Of the seven c-PAHs, B[a]A, B[b]F, and B[k]F are enriched in indoor and personal exposure concentrations from the outdoor coal-combustion. B[ghi]P, B[a]P, D[a,h]A, and IP, PAHs with some of the highest carcinogenic and mutagenic potencies, are considerably enriched by cigarette smoke in addition to the outdoor sources. PMID:24316321

  13. Polycyclic Aromatic Hydrocarbons (PAHs) in Indoor Dusts of Guizhou, Southwest of China: Status, Sources and Potential Human Health Risk

    PubMed Central

    Li, Baizhan

    2015-01-01

    Polycyclic aromatic hydrocarbons (PAHs) were analyzed for 136 indoor dust samples collected from Guizhou province, southwest of China. The ∑18PAHs concentrations ranged from 2.18 μg•g-1 to 14.20 μg•g-1 with the mean value of 6.78 μg•g-1. The highest Σ18PAHs concentration was found in dust samples from orefields, followed by city, town and village. Moreover, the mean concentration of Σ18PAHs in indoor dust was at least 10% higher than that of outdoors. The 4–6 rings PAHs, contributing more than 70% of ∑18PAHs, were the dominant species. PAHs ratios, principal component analysis with multiple linear regression (PCA-MLR) and hierarchical clustering analysis (HCA) were applied to evaluate the possible sources. Two major origins of PAHs in indoor dust were identified as vehicle emissions and coal combustion. The mean incremental lifetime cancer risk (ILCR) due to human exposure to indoor dust PAHs in city, town, village and orefield of Guizhou province, China was 6.14×10−6, 5.00×10−6, 3.08×10−6, 6.02×10−6 for children and 5.92×10−6, 4.83×10−6, 2.97×10−6, 5.81×10−6 for adults, respectively. PMID:25719362

  14. [Indoor air pollution with polycyclic aromatic hydrocarbons caused by polycyclic aromatic hydrocarbon containing parquet floor adhesives. Report of current status for evaluating and dealing with this "new chronic pollution" of indoor air].

    PubMed

    Heudorf, U

    1999-11-01

    In 1997 so far unknown indoor contaminations were detected in a flat of former American Forces living quarters in Frankfurt/Main, Germany. Household dust samples were found to be contaminated with polycyclic aromatic hydrocarbons (PAH), respectively with benzo(a)pyrene (BaP), due to the use of a coal tar pitch parquet glue that had been standard building practice in Germany up to the 'sixties. To assess the amount of exposure, the local Health Services department organised analyses of PAH metabolites in the urine of children below 6 years of age considered to be at risk for oral exposure to BaP in household dust while playing on the floor. In addition the local Health Services informed all ministeries concerned of the problem. During the following months several meetings on this topic were held by experts in the respective spheres and recommendations for redeveloping indoor sites were outlined. In almost 3,000 analyses of samples of household dust and parquet glue and about 1,200 urine analyses for PAH-metabolites in Frankfurt/Main no correlation was seen between the BaP levels in parquet glue and the BaP levels in household dust samples, as well as with interual exposure. Recommendations for further action were made in view of the importance of the composition of parquet flooring for possible indoor contamination. PMID:10628085

  15. Characterization of particulate and vapor phase polycyclic aromatic hydrocarbons in indoor and outdoor air of primary schools

    NASA Astrophysics Data System (ADS)

    Krugly, Edvinas; Martuzevicius, Dainius; Sidaraviciute, Ruta; Ciuzas, Darius; Prasauskas, Tadas; Kauneliene, Violeta; Stasiulaitiene, Inga; Kliucininkas, Linas

    2014-01-01

    The indoor air of schools is considered as one of the most important factors affecting the health of children. The aim of the presented research was to characterize polycyclic aromatic hydrocarbons (PAHs) in indoor and outdoor air of schools. The sampling campaign was conducted during the heating season of 2011/2012. Five primary schools from various urban settings in the city of Kaunas, Lithuania. 150 daily samples of particulate and vapor phases were collected during the sampling period. The ultrasonic extractions followed by the gas chromatography and mass spectroscopy (GS/MS) analyses were used for the determination of PAHs. The concentration of total PAHs in the PM2.5 fraction ranged from 20.3 to 131.1 ng m-3, while total suspended particles (TSP) fraction contained from 19.9 to 80.3 ng m-3 of total PAHs. The vapor phase concentration of PAHs ranged from 67.2 to 372.5 ng m-3. The most abundant PAH in both phases was naphthalene. In order to define sources of indoor and outdoor PAHs several source apportionment methods were applied. The analysis revealed that emissions from motor vehicles and fuel burning for heating purposes were the major sources of PAHs in the city of Kaunas.

  16. Evaluation of methods for simultaneous collection and determination of nicotine and polynuclear aromatic hydrocarbons in indoor air

    SciTech Connect

    Chuang, J.C.; Kuhlman, M.R. ); Wilson, N.K. )

    1990-05-01

    A study was performed to determine whether one sampling system and one analytical method can be used to collect and measure both polynuclear aromatic hydrocarbons (PAHs) and nicotine. PAH collection efficiencies for both XAD-2 and XAD-4 adsorbents were very similar, but nicotine collection efficiency was greater for XAD-4. Spiked perdeuterated PAHs were retained well in both adsorbents after exposure to more than 300 m{sup 3} of air. A two-step Soxhlet extraction, dichloromethane followed by ethyl acetate, was used to remove nicotine and PAHs from XAD-4. The extract was analyzed by positive chemical ionization or electron impact gas chromatography/mass spectrometry (GC/MS) to determine nicotine and PAHs. It is shown that one sampling system (quartz fiber filter and XAD-4 in series) and one analytical method (Soxhlet extraction and GC/MS) can be used for both nicotine and PAHs in indoor.

  17. Evaluation of methods for simultaneous collection and determination of nicotine and polynuclear aromatic hydrocarbons in indoor air

    SciTech Connect

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

    1990-01-01

    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. The PAH collection efficiencies for both XAD-2 and XAD-4 adsorbents are very similar, but the nicotine collection efficiency was greater for XAD-4. The spiked perdeuterated PAH were retained well in both adsorbents after exposure to more than 300 cu m of air. A two-step Soxhlet extraction, dichloromethane followed by ethylacetate, was used to remove nicotine and PAH from XAD-4. The extract was analyzed by positive chemical ionization or electron impact gas chromatography/mass spectrometry (GC/MS) to determine nicotine and PAH. It is shown that one sampling system (quartz fiber filter and XAD-4 in series) and one analytical method (Soxhlet extraction and GC/MS) can be used to measure both nicotine and PAH in indoor air.

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

    SciTech Connect

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

    1991-01-01

    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.

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

    SciTech Connect

    Gundel, L.A.; Daisey, J.M.; Mahanama, K.R.R.; Lee, V.C. ); Stevens, R.K. . Atmospheric Research and Exposure Assessment Lab.)

    1993-01-01

    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.

  20. 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...

  1. Concentrations, particle-size distributions, and indoor/outdoor differences of polycyclic aromatic hydrocarbons (PAHs) in a middle school classroom in Xi'an, China.

    PubMed

    Xu, Hongmei; Guinot, Benjamin; Niu, Xinyi; Cao, Junji; Ho, Kin Fai; Zhao, Zhuohui; Ho, Steven Sai Hang; Liu, Suixin

    2015-10-01

    Polycyclic aromatic hydrocarbons (PAHs) attached to particulate matter can affect respiratory health, especially the health of children, but information on the air quality in schools is generally lacking. This study investigated the PAH concentrations in a naturally ventilated classroom in Xi'an, China, from 16 to 31 May 2012. Particulate PAH concentrations were measured for samples collected on five-stage cascade impactors deployed inside the classroom and outside. PM2.5-bound PAH concentrations were 53.2 ng m(-3) indoors and 72.9 ng m(-3) outdoors. PAHs attached to very fine particles (VFPs) accounted for ~70% of the total PAHs. The PAH concentrations indoors were affected by the students' activities, cleaning, and smoking, while outdoors, the main sources were motor vehicle emissions and contaminated road dust. Particle-bound PAHs infiltrated the classroom through open windows, but the activities of the students and staff were also associated with an increase of PAHs attached to particles larger than 1.0 µm, most likely through resuspension. Cycles in the sources led to PAH concentrations 2-3 times higher on weekdays compared to weekends, both indoors and outdoors. PAH toxicity risks inside the classroom were substantially lower than those outdoors, and the highest risks were associated with VFPs. PMID:25537162

  2. Participant-based monitoring of indoor and outdoor nitrogen dioxide, volatile organic compounds, and polycyclic aromatic hydrocarbons among MICA-Air households

    NASA Astrophysics Data System (ADS)

    Johnson, Markey M.; Williams, Ron; Fan, Zhihua; Lin, Lin; Hudgens, Edward; Gallagher, Jane; Vette, Alan; Neas, Lucas; Özkaynak, Halûk

    2010-12-01

    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 conducted indoor and outdoor residential sampling of nitrogen dioxide (NO 2), volatile organic compounds (VOCs), and polycyclic aromatic hydrocarbons (PAHs). This participant-based methodology was subsequently adapted for use in the Vanguard phase of the U.S. National Children's Study. The current paper examines residential indoor and outdoor concentrations of these pollutant species among health study participants in Detroit, Michigan. Pollutants measured under MICA-Air agreed well with other studies and continuous monitoring data collected in Detroit. For example, NO 2 and BTEX concentrations reported for other Detroit area monitoring were generally within 10-15% of indoor and outdoor concentrations measured in MICA-Air households. Outdoor NO 2 concentrations were typically higher than indoor NO 2 concentration among MICA-Air homes, with a median indoor/outdoor (I/O) ratio of 0.6 in homes that were not impacted by environmental tobacco smoke (ETS) during air sampling. Indoor concentrations generally exceeded outdoor concentrations for VOC and PAH species measured among non-ETS homes in the study. I/O ratios for BTEX species (benzene, toluene, ethylbenzene, and m/p- and o-xylene) ranged from 1.2 for benzene to 3.1 for toluene. Outdoor NO 2 concentrations were approximately 4.5 ppb higher on weekdays versus weekends. As expected, I/O ratios pollutants were generally higher for homes impacted by ETS. These findings suggest that participant-based air sampling can provide a cost-effective alternative to technician-based approaches for assessing indoor and outdoor residential air pollution in community health studies. We also introduced a technique for estimating daily concentrations at each home by weighting 2- and 7-day integrated concentrations using continuous measurements from regulatory monitoring sites. This approach may be applied to estimate short-term daily or hourly pollutant concentrations in future health studies.

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

    SciTech Connect

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

    1993-01-01

    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.

  4. Emissions of parent, nitrated, and oxygenated polycyclic aromatic hydrocarbons from indoor corn straw burning in normal and controlled combustion conditions

    PubMed Central

    Shen, Guofeng; Xue, Miao; Wei, Siye; Chen, Yuanchen; Wang, Bin; Wang, Rong; Lv, Yan; Shen, Huizhong; Li, Wei; Zhang, Yanyan; Huang, Ye; Chen, Han; Wei, Wen; Zhao, Qiuyue; Li, Bin; Wu, Haisuo; Tao, Shu

    2014-01-01

    Emission factors (EFs) of parent polycyclic aromatic (pPAHs), nitrated PAHs (nPAHs), and oxygenated PAHs (oPAHs) were measured for indoor corn straw burned in a cooking brick stove in both normal and controlled burning conditions. EFs of total 28 pPAHs, 6 nPAHs and 4 oPAHs were 7.9±3.4, 6.5±1.6×10-3, and 6.1±1.4×10-1 mg/kg, respectively. By controlling the burning conditions, it was found that the influence of fuel charge size on EFs of the pPAHs and derivatives was insignificant. Measured EFs increased significantly in a fast burning mainly because of the oxygen deficient atmosphere formed in the stove chamber with a small volume. In both restricted and enhance air supply conditions, EFs of pPAHs, nPAHs and oPAHs were significantly higher than those measured in normal burning conditions. Though EFs varied in different burning conditions, the composition profiles and calculated isomer ratios were similar without significant differences. The results from the stepwise regression model showed that fuel burning rate, air supply amount, and modified combustion efficiency were three most significant influencing factors, explaining 72-85% of the total variations. PMID:24494494

  5. Effects of Heating Season on Residential Indoor and Outdoor Polycyclic Aromatic Hydrocarbons, Black Carbon, and Particulate Matter in an Urban Birth Cohort

    PubMed Central

    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.

    2010-01-01

    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 μm (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 Σ8PAHsemivolatile (MW 178–206), and Σ8PAHnonvolatile (MW 228–278)), Abs, and PM2.5; and 2) assess the relationship between PAH and ozone. Results showed that heating compared to nonheating season was associated with greater Σ8PAHnonvolatile (p<0.001) and Abs (p<0.05), and lower levels of Σ8PAHsemivolatile (p<0.001). In addition, the heating season was associated with lower I/O ratios of Σ8PAHnonvolatile and higher I/O ratios of Σ8PAHsemivolatile (p<0.001) compared to the nonheating season. In outdoor air, Σ8PAHnonvolatile 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. PMID:20938487

  6. Effects of Floor Level and Building Type on Residential Levels of Outdoor and Indoor Polycyclic Aromatic Hydrocarbons, Black Carbon, and Particulate Matter in New York City.

    PubMed

    Jung, Kyung Hwa; Bernabé, Kerlly; Moors, Kathleen; Yan, Beizhan; Chillrud, Steven N; Whyatt, Robin; Camann, David; Kinney, Patrick L; Perera, Frederica P; Miller, Rachel L

    2011-05-16

    Consideration of the relationship between residential floor level and concentration of traffic-related airborne pollutants may predict individual residential exposure among inner city dwellers more accurately. Our objective was to characterize the vertical gradient of residential levels of polycyclic aromatic hydrocarbons (PAH; dichotomized into Σ(8)PAH(semivolatile) (MW 178-206), and Σ(8)PAH(nonvolatile) (MW 228-278), black carbon (BC), PM(2.5) (particulate matter) by floor level (FL), season and building type. We hypothesize that PAH, BC and PM(2.5) concentrations may decrease with higher FL and the vertical gradients of these compounds would be affected by heating season and building type. PAH, BC and PM(2.5) were measured over a two-week period outdoor and indoor of the residences of a cohort of 5-6 year old children (n = 339) living in New York City's Northern Manhattan and the Bronx. Airborne-pollutant levels were analyzed by three categorized FL groups (0-2nd, 3rd-5th, and 6th-32nd FL) and two building types (low-rise versus high-rise apartment building). Indoor Σ(8)PAH(nonvolatile) and BC levels declined with increasing FL. During the nonheating season, the median outdoor Σ(8)PAH(nonvolatile,) but not Σ(8)PAH(semivolatile), level at 6th-2nd FL was 1.5-2 times lower than levels measured at lower FL. Similarly, outdoor and indoor BC concentrations at 6th-32nd FL were significantly lower than those at lower FL only during the nonheating season (p < 0.05). In addition, living in a low-rise building was associated significantly with higher levels of Σ(8)PAH(nonvolatile) and BC. These results suggest that young inner city children may be exposed to varying levels of air pollutants depending on their FL, season, and building type. PMID:21886868

  7. Personal and indoor exposure to PM₂.₅ and polycyclic aromatic hydrocarbons in the southern highlands of Tanzania: a pilot-scale study.

    PubMed

    Titcombe, Mari E; Simcik, Matt

    2011-09-01

    Personal and indoor exposure to PM(2.5) and polycyclic aromatic hydrocarbons (PAHs) were measured in households in the Njombe district of Tanzania. Cooking is conducted indoors in this region due to its high elevation, cool climate, and heavy seasonal rainfall. Kitchens are often poorly ventilated, resulting in high exposures to combustion-related pollutants. Sampling sites were selected to represent typical cooking practices across regional socio-economic divisions. These include the use of open wood fires, charcoal, a mix of charcoal and kerosene, and liquid petroleum gas (LPG) for cooking fuels. PM(2.5) average personal exposure was 14 μg/m(3) (±3, n = 3) for LPG, 88 μg/m(3) (±42, n = 3) for kerosene/charcoal mix, 588 μg/m(3) (±347, n = 3) for charcoal alone, and 1574 μg/m(3) (±287, n = 3) for open wood fires. Total PAH average personal exposures were less than 1 ng/m(3) (±1, n = 3) for LPG, 57 ng/m(3) (±16, n = 3) for kerosene/charcoal mix, 334 ng/m(3) (±57, n = 3) for charcoal alone, and 5040 ng/m(3) (±909, n = 3) for open wood fires. Benzo[a]pyrene equivalent exposures for US EPA's priority PAH pollutants were 0 for LPG, 8 ng/m(3) for kerosene/charcoal mix, 44 ng/m(3) for charcoal, and 767 ng/m(3) for open wood fire. Inhalable pollutants are present at unacceptably high levels, exceeding indoor air quality standards for all but LPG fuels. Relative results provide an exposure profile for rural East Africa and support the feasibility of conducting a larger scale smoke exposure campaign in the region. The use of "fuel efficient" wood stoves for the reduction of PM(2.5) and PAH exposure was measured in a local secondary school. Proper use of "fuel efficient" wood stoves reduced personal and indoor exposure to measured pollutants by more than 90%, supporting further investigation into the applicability of this technology to significantly improve indoor air quality. PMID:21136289

  8. Estimating individual-level exposure to airborne polycyclic aromatic hydrocarbons throughout the gestational period based on personal, indoor, and outdoor monitoring

    SciTech Connect

    Choi, H.; Perera, F.; Pac, A.; Wang, L.; Flak, E.; Mroz, E.; Jacek, R.; Chai-Onn, T.; Jedrychowski, W.; Masters, E.; Camann, D.; Spengler, J.

    2008-11-15

    Current understanding on health effects of long-term polycyclic aromatic hydrocarbon (PAH) exposure is limited by lack of data on time-varying nature of the pollutants at an individual level. In a cohort of pregnant women in Krakow, Poland, we examined the contribution of temporal, spatial, and behavioral factors to prenatal exposure to airborne PAHs within each trimester and developed a predictive model of PAH exposure over the entire gestational period. The observed personal, indoor, and outdoor B(a)P levels we observed in Krakow far exceed the recommended Swedish guideline value for B(a)P of 0.1 ng/m{sup 3}. Based on simultaneously monitored levels, the outdoor PAH level alone accounts for 93% of total variability in personal exposure during the heating season. Living near the Krakow bus depot, a crossroad, and the city, center and time spent outdoors or commuting were not associated with higher personal exposure. During the nonheating season only, a 1-hr increase in environmental tobacco smoke (ETS) exposure was associated with a 10-16% increase in personal exposure to the nine measured PAHs. A 1{degree}C decrease in ambient temperature was associated with a 3-5% increase in exposure to benz(a)anthracene, benzo(k)fluoranthene, and dibenz(a,h)anthracene, after accounting for the outdoor concentration. A random effects model demonstrated that mean personal exposure at a given gestational period depends on the season, residence location, and ETS. Considering that most women reported spending < 3 hr/day outdoors, most women in the study were exposed to outdoor-originating PAHs within the indoor setting. Cross-sectional, longitudinal monitoring supplemented with questionnaire data allowed development of a gestation-length model of individual-level exposure with high precision and validity.

  9. 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

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

    1987-11-01

    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.

  10. Bioassay of polycyclic aromatic hydrocarbons

    SciTech Connect

    Van Kirk, E.A.

    1980-08-01

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

  11. Polycyclic Aromatic Hydrocarbons

    NASA Technical Reports Server (NTRS)

    Salama, Farid

    2010-01-01

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

  12. Indoor-outdoor levels of size segregated particulate matter and mono/polycyclic aromatic hydrocarbons among urban areas using solid fuels for heating

    NASA Astrophysics Data System (ADS)

    Kliucininkas, Linas; Krugly, Edvinas; Stasiulaitiene, Inga; Radziuniene, Inga; Prasauskas, Tadas; Jonusas, Arunas; Kauneliene, Violeta; Martuzevicius, Dainius

    2014-11-01

    Emissions from the fuel combustion in the energy production are causes of concern due to associated health risks, but little information is available on the impact of residential fuel burning on indoor air quality, where most of the human exposure occurs. In this complex study, concentrations of size-segregated particulate matter (PM), monocyclic and polycyclic aromatic compounds (MAHs and PAHs) at indoor and outdoor sites in six urban homes in the city of Kaunas, Lithuania, were determined over winter and summer sampling campaigns, specifically targeting the impact of the local fuel burning to the indoor air quality. PM levels observed in Kaunas during winter measurement campaign were higher compared to those in many other European settlements utilizing biomass for energy production. The particle size distribution analysis revealed that the major part of the PM mass in winter period consisted of fine particles (PM2.5). Both MAH and PAH levels were higher in winter. The indoor to outdoor ratios (I/O) of MAHs and PAHs revealed specific patterns depending on the presence of emissions sources indoors. Irrespectively of the season, I/O values were <1, suggesting that in case of the absence of an indoor pollution, the dominant source of organic compounds was from the outdoor environment. In homes with no PAH source inside, the I/O ratio equalled ranged from 0.05 to 0.36, suggesting the penetrated portion of outdoor combustion particles to the indoor air.

  13. THE PHOTOTOXICITY OF POLYCYCLIC AROMATIC HYDROCARBONS

    EPA Science Inventory

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

  14. Deuterated polycyclic aromatic hydrocarbons: Revisited

    NASA Astrophysics Data System (ADS)

    Doney, K. D.; Candian, A.; Mori, T.; Onaka, T.; Tielens, A. G. G. M.

    2016-02-01

    Aims: The amount of deuterium locked up in polycyclic aromatic hydrocarbons (PAHs) has to date been an uncertain value. We present a near-infrared (NIR) spectroscopic survey of Hii regions in the Milky Way, Large Magellanic Cloud, and Small Magellanic Cloud obtained with AKARI, which aims to search for features indicative of deuterated PAHs (PAD or Dn-PAH) to better constrain the D/H ratio of PAHs. Methods: Fifty-three Hii regions were observed in the NIR (2.5-5 μm), using the Infrared Camera (IRC) on board the AKARI satellite. Through comparison of the observed spectra with a theoretical model of deuterated PAH vibrational modes, the aromatic and (a)symmetric aliphatic C-D stretch modes were identified. Results: We see emission features between 4.4-4.8 μm, which could be unambiguously attributed to deuterated PAHs in only six of the observed sources, all of which are located in the Milky Way. In all cases, the aromatic C-D stretching feature is weaker than the aliphatic C-D stretching feature, and, in the case of M17b, this feature is not observed at all. Based on the weak or absent PAD features in most of the observed spectra, it is suggested that the mechanism for PAH deuteration in the ISM is uncommon.

  15. Deuterated Interstellar Polycyclic Aromatic Hydrocarbons

    NASA Astrophysics Data System (ADS)

    Peeters, E.; Allamandola, L. J.; Bauschlicher, C. W., Jr.; Hudgins, D. M.; Sandford, S. A.; Tielens, A. G. G. M.

    2004-03-01

    We report infrared spectral evidence of deuterated interstellar polycyclic aromatic hydrocarbons (PAHs). Two bands are detected in the infrared emission from the ionization bar in Orion at 4.4 and 4.65 μm. The one at 4.65 μm is present at the 4.4 σ level, while the one at 4.4 μm is more tentative, with a σ equal to 1.9. An emission band at 4.65 μm is also detected in the infrared emission from M17 by Verstraete and coworkers at the 4.4 σ level. These wavelengths are highly characteristic of CD stretching modes of deuterated PAHs and fall in a featureless region of the interstellar spectrum. The IR spectroscopic properties of deuterated PAHs are summarized, and an estimate of the deuterium fractionation between the aromatic and aliphatic carbons associated with the PAHs is given. High deuterium fractionation is implied; this is discussed in terms of interstellar PAH fractionation mechanisms. Based on observations made with ISO, an ESA project with instruments funded by ESA member states (especially the principal investigator countries: France, Germany, the Netherlands, and the United Kingdom), with the participation of ISAS and NASA.

  16. Birds and polycyclic aromatic hydrocarbons

    USGS Publications Warehouse

    Albers, P.H.

    2006-01-01

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

  17. Polynuclear aromatic hydrocarbons for fullerene synthesis in flames

    DOEpatents

    Alford, J. Michael; Diener, Michael D.

    2006-12-19

    This invention provides improved methods for combustion synthesis of carbon nanomaterials, including fullerenes, employing multiple-ring aromatic hydrocarbon fuels selected for high carbon conversion to extractable fullerenes. The multiple-ring aromatic hydrocarbon fuels include those that contain polynuclear aromatic hydrocarbons. More specifically, multiple-ring aromatic hydrocarbon fuels contain a substantial amount of indene, methylnapthalenes or mixtures thereof. Coal tar and petroleum distillate fractions provide low cost hydrocarbon fuels containing polynuclear aromatic hydrocarbons, including without limitation, indene, methylnapthalenes or mixtures thereof.

  18. Infrared Spectra of Polycyclic Aromatic Hydrocarbons (PAHs)

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

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

  19. Reaction of monosubstituted aromatic hydrocarbons with styrene

    SciTech Connect

    Grushin, A.I.; Grigor'ev, V.V.; Prokof'ev, K.V.; Kozlova, N.M.

    1986-03-20

    1,1-Phenylarylethanes were obtained by the reaction of styrene with some monosubstituted aromatic hydrocarbons in the presence of titanium tetrachloride. It was established that electron-donating substituents have an effect on the yield of the arylalkylation products.

  20. PROTONATED POLYCYCLIC AROMATIC HYDROCARBONS REVISITED

    SciTech Connect

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

    2011-02-01

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

  1. 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)

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

    2011-04-01

    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.

  2. Bicyclic aromatic hydrocarbons of Kuwait gas oil

    SciTech Connect

    Ijam, M.J.; Al-Qatami, S.Y.; Arif, S.F. )

    1990-08-01

    For several decades removal of aromatics from crude oil fractions has been practiced in oil refining to produce fuels and lubricants of lower aromatic content and hence of improved quality. These aromatics are suitable raw materials for the manufacture of aromatic solvents, aromatic process oils, high octane gasoline, and as basic materials for making detergents, perfumes and dyes. A study for the UV and IR spectra of the aromatic hydrocarbons showed them to consist mainly of bi-, tri-, tetra-, and penta-substituted benzene, bicyclic and tricyclic compounds. Detailed studies have been reported of molecular structure and substituent effects have been reported on the retention characteristics of aromatic hydrocarbons on alumina, silica and various chemically bonded silicas containing {minus}C{sub 18}, {minus}NH{sub 2}, {minus}R(NH){sub 2}, {minus}CN, RCN, and phenyl-mercuric acetate for compound class (ring-numbered) high performance liquid chromatography separation. With the aid of a Finnegan type 9612-4000 GC/MS apparatus, the mixture of neutral + basic aromatic hydrocarbons was qualitatively identified and revealed the presence of more than 112 peaks. The neutral + basic aromatic hydrocarbons consist mainly of: 3.68% monoaromatics (C{sub 3} - C{sub 6} alkyl benzenes), 52.81% bicycloaromatics (C{sub 0} - C{sub 4} alkylnaphthalenes), 6.20% tricycloaromatics (C{sub 0} - C{sub 4} alkyl phenanthrenes), and 37.32% nonhydrocarbons aromatic compounds. The components in major HPLC peaks corresponding to bicycloaromatics were further separated into small groups (3-4 components in each) by HPLC using an ODS-reverse phase-C{sub 18} column. To separate a single component from the mixture is a difficult problem. The individual compounds in the separated fractions were identified by GC/MS (Hewlett Packard 5993 system).

  3. 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...

  4. Polycyclic aromatic hydrocarbon selected galaxies

    NASA Astrophysics Data System (ADS)

    Haas, M.; Leipski, C.; Siebenmorgen, R.; Meusinger, H.; Drass, H.; Chini, R.

    2009-11-01

    Context: This is the fourth in a series of papers based on the ISOCAM Parallel Survey at 6.7 μm. While the first three papers have been devoted to active galactic nuclei (AGN), here we report on emission-line galaxies without AGN signatures in their optical spectra. Aims: Polycyclic aromatic hydrocarbon (PAH) emission has been found in both starbursts and modestly starforming galaxies, but the relation between starforming activity and PAH luminosity is still a matter of debate. The different correlation degrees could be caused by the variety of optical and far-infrared sample selection criteria. In order to obtain a census of the typical properties of PAH emitting galaxies, we here study moderately distant galaxies which have been selected by their PAH emission. Methods: Combining the ISOCAM Parallel Survey at 6.7 μm with 2MASS we have colour-selected a sample of 120 candidates for strong PAH emission. We obtained optical and mid-infrared spectra of 75 and 19 sources, respectively, and analysed IRAS-ADDSCANs and available Spitzer 3.6-160 μm photometry. Results: The Spitzer mid-infrared spectra exhibit clear PAH features and corroborate that our photometric selection criteria trace the PAH emission of galaxies fairly well. The optical spectra show emission lines, at median redshift z ˜ 0.1, as well as Hδ and Ca II absorption, indicating ongoing starformation as well as post-starbursts. The mid- and far-infrared spectral energy distributions (SEDs) provide evidence for a broad range of far-infrared (FIR) luminosities (109 L⊙-2 × 1012 L⊙), but in general the dust is colder (T ⪉ 25 K, β=2) than for starburst galaxies like M 82 (T ≈ 40 K). For most galaxies the monocromatic luminosity (ν \\cdot Lν) peaks at about equal height at optical, 6.7 μm (PAH) and FIR wavelengths. In about 15% of the sources the FIR luminosity exceeds the optical and PAH energy output by about a factor 5-10 despite the cool dust temperature; in these galaxies a large dust mass of 108-109 M⊙ is inferred. Conclusions: At moderate distance (z ˜ 0.1), PAH selected galaxies turn out to be a quite heterogeneous population of dust-rich, partly infrared-luminous galaxies but mostly cool with a range of post-starburst signatures and starforming activity which appears to be rather modest relative to the entire gas content (derived from the dust mass and assuming a standard gas/dust ratio). Our results on PAH selected galaxies question the often expressed interpretation that the majority of high redshift galaxies detected in 15 and 24 μm surveys are dominated by powerful ongoing starbursts with high starforming efficiency. Tables 1-3 are only available in electronic form at http://www.aanda.org

  5. On the aromatic stabilization of benzenoid hydrocarbons.

    PubMed

    Ciesielski, Arkadiusz; Stepień, Dorota K; Dobrowolski, Michał A; Dobrzycki, Łukasz; Cyrański, Michał K

    2012-10-18

    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

  6. 40 CFR 721.10258 - Aromatic hydrocarbon (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Aromatic hydrocarbon (generic). 721... Substances § 721.10258 Aromatic hydrocarbon (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as aromatic hydrocarbon (PMN...

  7. 40 CFR 721.10258 - Aromatic hydrocarbon (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Aromatic hydrocarbon (generic). 721... Substances § 721.10258 Aromatic hydrocarbon (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as aromatic hydrocarbon (PMN...

  8. 40 CFR 721.10259 - Halogenated aromatic hydrocarbon (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Halogenated aromatic hydrocarbon... Specific Chemical Substances § 721.10259 Halogenated aromatic hydrocarbon (generic). (a) Chemical substance... halogenated aromatic hydrocarbon (PMN P-09-540) is subject to reporting under this section for the...

  9. 40 CFR 721.10258 - Aromatic hydrocarbon (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Aromatic hydrocarbon (generic). 721... Substances § 721.10258 Aromatic hydrocarbon (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as aromatic hydrocarbon (PMN...

  10. 40 CFR 721.10259 - Halogenated aromatic hydrocarbon (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Halogenated aromatic hydrocarbon... Specific Chemical Substances § 721.10259 Halogenated aromatic hydrocarbon (generic). (a) Chemical substance... halogenated aromatic hydrocarbon (PMN P-09-540) is subject to reporting under this section for the...

  11. 40 CFR 721.10259 - Halogenated aromatic hydrocarbon (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Halogenated aromatic hydrocarbon... Specific Chemical Substances § 721.10259 Halogenated aromatic hydrocarbon (generic). (a) Chemical substance... halogenated aromatic hydrocarbon (PMN P-09-540) is subject to reporting under this section for the...

  12. Carbon fibers from aromatic hydrocarbons

    SciTech Connect

    Mochida, Isao; Yoon, S.H.; Korai, Yozo; Kanno, Koichi; Sakai, Yukio; Komatsu, Makoto

    1995-02-01

    Carbon filter is widely used as a lightweight and high-strength material for composite structures. Its uses are expected to expand in the next century. Currently the best precursor for making these fibers is polyacrylonitrile (PAN). This is a relatively expensive feedstock. Carbon fibers also have been made starting with so-called mesophase pitch fractions derived from low-cost hydrocarbons such as petroleum residuum. But these fibers suffer from low mechanical strength. In the past few years, significant advances have been made in understanding the mechanism of formation of mesophase pitch, which may lead to improved performance for carbon fibers and other specialty carbons. This article introduces such advances, based principally on the authors` recent results.

  13. Monitoring of vapor phase polycyclic aromatic hydrocarbons

    DOEpatents

    Vo-Dinh, Tuan; Hajaligol, Mohammad R.

    2004-06-01

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

  14. 40 CFR 721.10676 - Aromatic hydrocarbon mixture (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Aromatic hydrocarbon mixture (generic... Specific Chemical Substances § 721.10676 Aromatic hydrocarbon mixture (generic). (a) Chemical substance and... hydrocarbon mixture (PMN P-12-551) is subject to reporting under this section for the significant new...

  15. 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...

  16. 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). ...

  17. 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...

  18. Polycyclic aromatic hydrocarbons for organic photovoltaics

    NASA Astrophysics Data System (ADS)

    Wong, Wallace W.

    2011-12-01

    Hexa-peri-hexabenzocoronene (HBC) is a disc-shaped polycyclic aromatic hydrocarbon with remarkable self-association properties. Solution processable alkyl substituted HBC compounds often exhibit discotic liquid crystalline behavior and have been shown to carry charges efficiently in bulk. In recent years, fluorenyl HBC (FHBC) compounds have emerged as promising materials for organic photovoltaics. The fluorene substituent imparts solution processability while maintaining good charge transport characteristics. Power conversion efficiency close to 3% has been reported for organic solar cell devices containing FHBC materials.

  19. Halogenated polycyclic aromatic hydrocarbons in the environment.

    PubMed

    Sun, Jian-Lin; Zeng, Hui; Ni, Hong-Gang

    2013-02-01

    Halogenated polycyclic aromatic hydrocarbons (HPAHs) have been reported to occur in air, sediment, fly ash, and biota samples. This review summarized current existing data on the environmental occurrence, behavior, physicochemical properties, emission sources, and toxic equivalents of HPAHs. Firstly, the physicochemical properties of HPAHs were summarized. Then, an overview of environmental occurrence of HPAHs in ambient matrices including biological samples was reviewed. Meanwhile, the emission sources and possible formation mechanisms of HPAHs were discussed. Apart from that, the aryl hydrocarbon receptor (AhR)-mediated activities were summarized, which indicated that the position and number of halogen atoms on the parent PAHs molecule were important determinant factors affecting the AhR-mediated activity of individual HPAHs congeners. Finally, some research recommendations on HPAHs were given. PMID:23182112

  20. Laboratory Investigation of Organic Aerosol Formation from Aromatic Hydrocarbons

    DOE R&D Accomplishments Database

    Molina, Luisa T.; Molina, Mario J.; Zhang, Renyi

    2006-08-23

    Our work for this DOE funded project includes: (1) measurements of the kinetics and mechanism of the gas-phase oxidation reactions of the aromatic hydrocarbons initiated by OH; (2) measurements of aerosol formation from the aromatic hydrocarbons; and (3) theoretical studies to elucidate the OH-toluene reaction mechanism using quantum-chemical and rate theories.

  1. Continuous removal of polynuclear aromatics from hydrocarbon recycle oil

    SciTech Connect

    Bosserman, P.J.; Taniguchi, V.T.

    1992-06-23

    This patent describes an oil refining process. It comprises forming a liquid capable of solubilizing aromatic compounds having at least about 5 fused aromatic rings; and catalytically hydrocracking a hydrocarbon feedstock by: contacting the feedstock in a hydrocracking zone with added hydrogen and a hydrocracking zone with added hydrogen and a hydrocracking catalyst at a temperature and pressure sufficient to give a substantial conversion to lower boiling products; and condensing a hydrocarbon effluent from the hydrocracking zone and separating the condensed effluent into (AA) a low boiling hydrocarbon product and (BB) an unconverted hydrocarbon oil containing one or more fused polynuclear aromatic compounds.

  2. Simplified determination of polycyclic aromatic hydrocarbons.

    PubMed

    Avery, M J; Richard, J J; Junk, G A

    1984-01-01

    Accurate quantitative analysis for selected polycyclic aromatic hydrocarbons present on urban dust can be obtained by using a simple procedure consisting of sonic-probe extraction with cyclohexane; clean-up with Florisil((R))-XAD-4((R)), and measurement by high-resolution gas chromatography with flame-ionization detection (HRGC/FID). The analysis can be further simplified by eliminating the clean-up step if HRGC/electron-impact mass-spectrometry (MS) is available. Both the FID and MS methods give results consistent with those obtained by standard procedures. The direct HRGC/MS procedure, combined with chemical ionization, can also be applied to the determination of polycyclic organic materials present in solvent-refined coal, shale oil and crude oil. PMID:18963526

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

    PubMed

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

    2015-01-01

    The concentrations and distributions of major polycyclic aromatic hydrocarbons (PAHs) were determined in 20 kinds of yogurt specimens collected from Italian supermarkets using reversed phase high-performance liquid chromatography equipped with fluorescence detection. The method was validated by determination of recovery percentages, precision (repeatability) and sensitivity (limits of detection) with yogurt samples fortified at 0.25, 0.5 and 1 µg/kg concentration levels. The recovery of 13 PAHs, with the exception of naphthalene and acenaphthene, ranged from 61% to 130% and from 60% to 97% at all the levels for yogurts with low (0.1%) and high (3.9%) fat content, respectively. The method is repeatable with relative standard deviation values <20% for all analytes. The results obtained demonstrate that acenaphthene, fluorantene, phenanthrene, anthracene, fluoranthene and pyrene were found in all samples with a similar distribution, but different content when yogurts with low and high fats were compared. PMID:25257517

  4. Polycyclic aromatic hydrocarbons and cancer in man

    SciTech Connect

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

    1996-11-01

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

  5. Assessing indoor air exposures using passive sampling with bioanalytical methods for estrogenicity and aryl hydrocarbon receptor activity

    PubMed Central

    Macova, Miroslava; Leusch, Frederic; Bartkow, Michael E.; Hawker, Darryl W.; Zhao, Bin; Denison, Michael S.; Mueller, Jochen F.

    2010-01-01

    Passive air sampling was undertaken using polyurethane foam passive air samplers at three types of locations, including indoors (six offices) at buildings in the central business district (CBD) and at a private suburban home (indoor and outdoor) located 9 km from the CBD in Brisbane, Queensland, Australia. Estrogenic (E-SCREEN—MCF7-BOS) and aryl hydrocarbon receptor (AhR) (CAFLUX— H4G1.1c2) activity were assessed for samples collected from each of these locations. The samples were tested either as crude extracts (“untreated”) or were subjected to H2SO4 silica gel (“treated”) for each location in order to determine whether chemicals, which are not resistant to this treatment like polycyclic aromatic hydrocarbons, potentially account for the observed activity. In most cases, H2SO4 treatment resulted in a statistically significant reduction of potency for both endpoints, suggesting that chemicals less resistant to treatment may be responsible for much of the detected biological activity in these locations. Estrogenic potency measurements (<0.22–185 pg m−3) were highest in the indoor offices, followed by the indoor suburban home and finally the outdoor suburban home (which was not estrogenic). Total AhR activity for crude extracts (1.3–10 pg m−3) however was highest for the outdoor suburban home site. Levels of polycyclic aromatic hydrocarbons were monitored indoors and outdoors at the suburban home. At that location, polycyclic aromatic hydrocarbon air concentrations were on average approximately two times higher outdoor than indoor, while AhR potency was five times higher outdoor than indoor. No significant correlation was found between the estrogenic and AhR activity (P=0.88) for the sites in this study. PMID:19430962

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

    EPA Science Inventory

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

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

    EPA Science Inventory

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

  8. ADSORPTION OF POLYCYCLIC AROMATIC HYDROCARBONS IN AGED HARBOR SEDIMENTS

    EPA Science Inventory

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

  9. 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...

  10. Provisional Guidance for Quantitative Risk Assessment of Polycyclic Aromatic Hydrocarbons

    EPA Science Inventory

    Polycyclic Aromatic Hydrocarbons (PAHs) are products of incomplete combustion of organic materials; sources are, thus, widespread,including cigarette smoke, municipal waste incineration, wood stove emissions, coal conversion, energy production form fossil fuels, and automobile an...

  11. Polycyclic aromatic hydrocarbons and childhood asthma.

    PubMed

    Karimi, Parisa; Peters, Kamau O; Bidad, Katayoon; Strickland, Paul T

    2015-02-01

    Asthma is the most common chronic illness in children living in developed countries and the leading cause of childhood hospitalization and school absenteeism. Prevalence rates of asthma are increasing and show disparities across gender, geographic regions, and ethnic/racial groups. Common risk factors for developing childhood asthma include exposure to tobacco smoke, previous allergic reactions, a family history of asthma, allergic rhinitis or eczema, living in an urban environment, obesity and lack of physical exercise, severe lower respiratory tract infections, and male gender. Asthma exacerbation in children can be triggered by a variety of factors, including allergens (e.g., pollen, dust mites, and animal dander), viral and bacterial infections, exercise, and exposure to airway irritants. Recent studies have shown that exposure to polycyclic aromatic hydrocarbons (PAHs), a major component of fine particulate matter from combustion sources, is also associated with onset of asthma, and increasing asthmatic symptoms. In this paper, we review sources of childhood PAH exposure and the association between airborne PAH exposure and childhood asthma prevalence and exacerbation. PMID:25600297

  12. Polycyclic aromatic hydrocarbon molecules in astrophysics

    NASA Astrophysics Data System (ADS)

    Rastogi, Shantanu; Pathak, Amit; Maurya, Anju

    2013-06-01

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

  13. Ultrasonic degradation of polycyclic aromatic hydrocarbons

    SciTech Connect

    Park, J.K.; Yen, T.F.

    1995-12-31

    Trace amounts of the polycyclic aromatic hydrocarbons (PAHs) present in the environment are of concern due to their hazardous nature. Conventional processes for degrading PAH are time consuming and inefficient, and they require costly equipment; furthermore, they contribute to other problems. Ultrasound can provide the highly energetic hydrogen atom and hydroxyl radicals, whose reactivity accounts for the destruction of organic solutes, in a very short time. The degradation mechanisms and the degradation efficiency for 1-methylnaphthalene, anthracene, phenanthrene, pyrene, 1,12-benzoperylene, and coronene, in dilute organic solvent-water solutions, were studied under ultrasound on a laboratory scale. The extent of degradation is followed by ultraviolet (UV)-visible spectrometry. The effects of additional agents, such as hydrogen peroxide, sodium borohydride, and dissolved gas, were investigated. The catalytic effects of ferrous chloride and nickel chloride were investigated. A total of 70 to 83% of PAH was degraded as a result of the additional agents and 2 hours of ultrasound. The higher percentage of degradation was caused by the greater abundance of free radicals, especially hydroxyl, for cleavage. However, with the catalysts, the added PAH degradation efficiency was not significant.

  14. Polycyclic aromatic hydrocarbons in the bakery chain.

    PubMed

    Ciecierska, M; Obiedziński, M W

    2013-11-01

    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 μg/kg and, in bread, from 1.59 to 13.6 μg/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

  15. Overtone emission from interstellar polycyclic aromatic hydrocarbons

    NASA Astrophysics Data System (ADS)

    Duley, W. W.

    1994-07-01

    The origin of 3.40 micrometers, 3.51 micrometers, and other emission lines that accompany the 3.28 micrometers feature observed in many nebulae is discussed. The assignment of 3.40 and 3.51 micrometers emission to 2 to 1 and 3 to 2 transitions, respectively, of the fundamental CH stretch in relatively small polycyclic aromatic hydrocarbon (PAH) molecules is shown to be plausible even in the absence of 2 to 0 1.67 micrometers overtone emission if the emitters (1) have a center of symmetry and (2) are in the gas phase. An analysis of electric-dipole-allowed transitions in such molecules shows that, while the 1.67 micrometers 2 to 0 overtone is forbidden, overtones of other fundamentals should occur in this spectral region, but not generally at 1.67 micrometers. The 3 to 0 overtone of the fundamental CH stretch is allowed and would occur at lambda = 1.1325 micrometers (8830 cm-1. An emission feature at this wavelength may be present in spectra of NGC 7027 and BD +30 deg. 3639.

  16. Polynuclear aromatic hydrocarbons in the water environment*

    PubMed Central

    Andelman, Julian B.; Suess, Michael J.

    1970-01-01

    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. PMID:4100719

  17. Emission of polycyclic aromatic hydrocarbons in China

    SciTech Connect

    Shanshan Xu; Wenxin Liu; Shu Tao

    2006-02-01

    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.

  18. Dependence of the extractability of aromatic hydrocarbons on their structure

    SciTech Connect

    Yanbukhtina, R.A.; Semenov, L.V.; Gaile, A.A.; Li, I.F.

    1988-08-10

    Liquid extraction is widely used in industry for extracting aromatic hydrocarbons from reforming catalyzates and hydrorefined pyrocondensates, and for purification of components which worsen the operating properties of fuels and oils from kerosene-gas oil and oil fractions of petroleum. The maximum distribution coefficients of arenes of different structure were determined in extraction from mixtures with n-tetradecane by acetonitrile (AN), previously proposed for purification of aromatic impurities from liquid paraffins, for a more complete study of the effect of the structure of aromatic hydrocarbons on their extractability. The conditions and results of one-stage extraction are reported. The concentration of arenes in the equilibrium phases was determined spectrophotometrically. The results obtained on the relative extractability of hydrocarbons can be used in selecting the key components in processes of extraction separation of different types of hydrocarbon raw material.

  19. In vitro toxicity of polycyclic aromatic hydrocarbons and halogenated aromatic hydrocarbons to cetacean cells and tissues

    SciTech Connect

    Carvan, M.J. III.

    1993-01-01

    Cetaceans bioaccumulate high aromatic hydrocarbon tissue residues, and elevated levels of PCB residues in tissues are proposed to have occurred concurrently with recent epizootic deaths of dolphins. The objectives of this study were: (1) to develop and characterize an epithelial cell line derived from dolphin tissues, (2) to investigate the effects of hydrocarbon pollutants on those cells, and (3) to analyze the toxicity of hydrocarbon pollutants on cetacean tissues in vitro. An epithelial cell line, Carvan dolphin kidney (CDK), isolated from a spontaneously aborted female bottlenose dolphin, Tursiops truncatus, grew rapidly. These cells were neither transformed nor immortal. Velocity sedimentation analysis showed CDK cells contained nuclear aryl hydrocarbon receptor, suggestive of cytochrome P450 inducibility. BaP inhibited mitosis in CDK cells in a dose-dependent manner. Data indicate that CDK cells metabolize BaP, that BaP metabolites bind to cellular DNA initiating unscheduled DNA synthesis, and that the inhibition of cytochrome P450 metabolism decrease the BaP-associated inhibition of mitosis in dolphin cells. The data also suggest that TCDD acts synergistically to increase the levels of DNA damage by the procarcinogen BaP. Cetacean liver microsomes was isolated and evaluated for the presence of cytochrome P450 proteins by SDS-PAGE, apparent minimum molecular weight determination, and immunoblot analysis. P450 activity was induced in cetacean tissue samples and CDK cells by exposure in vitro to one of several cytochrome P450-inducing chemicals. The data suggest that cetacean tissues and cells can be utilized to study the in vitro induction of cytochrome P450, resultant metabolism of xenobiotic contaminants, and the subsequent cellular and molecular responses. However, the identity of specific P450 isozymes involved in this process will remain undetermined until monoclonal antibodies that recognize cetacean P450s can be generated.

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

    EPA Science Inventory

    Abstract

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

  1. Polycyclic Aromatic Hydrocarbon Far-infrared Spectroscopy

    NASA Astrophysics Data System (ADS)

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

    2011-03-01

    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 μm. 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.

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

    PubMed

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

    2014-08-30

    Contaminations in sediments by polycyclic aromatic hydrocarbons (PAHs) and alkylated PAHs were investigated at 44 sites in Osaka Bay, Japan. Concentrations of total PAHs and alkylated PAHs were in the range 6.40-7800 ng/g dry weights and 13.7-1700 ng/g dry weights, respectively. The PAH concentrations tended to be higher along the shoreline in the vicinities of big ports, industrialized areas, and densely populated regions such as the cities of Osaka and Kobe. The major sources appeared to be pyrogenic or both pyrogenic and petrogenic at most of the sites. PAH concentrations were remarkably high at a site near Kobe, where the concentrations of dibenzo(a,h)anthracene and benzo(g,h,i)perylene exceeded the effects-range-medium concentration and eight PAHs were above the corresponding effects-range-low concentrations. Those PAHs may have been derived from the great fire associated with the large earthquake in 1995. PMID:24775067

  3. Environmental Behaviors and Toxicities of Polycyclic Aromatic Hydrocarbons and Nitropolycyclic Aromatic Hydrocarbons.

    PubMed

    Hayakawa, Kazuichi

    2016-01-01

    Airborne particulate matter (PM) has been collected at four cities in Japan starting in the late 1990s, at five or more major cities in China, Korea and Russia starting in 2001 and at the Noto Peninsula starting in 2004. Nine polycyclic aromatic hydrocarbons (PAHs) and eleven nitropolycyclic aromatic hydrocarbons (NPAHs) were determined by HPLC with fluorescence and chemiluminescence detections, respectively. Annual concentrations of PAHs and NPAHs were in the order, China>Russia≫Korea=Japan, with seasonal change (winter>summer). During the observation period, concentrations of PAHs and NPAHs in Japanese cities significantly decreased but the increases in the PAH concentration were observed in Chinese and Russian cities. Concentrations of PAHs and NPAHs were higher in the Northern China than those in the Southern China. At the Noto peninsula, which is in the main path of winter northwest winds and a year-round jet stream that blow from the Asian continent to Japan, the concentrations were high in winter and low in summer every year. A cluster analysis and back trajectory analysis indicated that PAHs and NPAHs were long-range transported from Northeastern China, where coal burning systems such as coal-heating boilers are considered to be the major contributors of PAHs and NPAHs. A dramatic change in atmospheric concentrations of PAHs and NPAHs in East Asia suggests the rapid and large change of PM2.5 pollution in East Asia. Considering the adverse health effects of PM2.5, continuous monitoring of atmospheric PAHs and NPAHs is necessary in this area. PMID:26833435

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

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

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

  5. Exposure to polycyclic aromatic hydrocarbons among Dutch children.

    PubMed Central

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

    1996-01-01

    We determined the urinary 1-hydroxypyrene (1-HP) concentration and the creatinine-adjusted 1-HP concentration in 644 randomly selected Dutch children, aged 1-6 years and living in five areas with roughly different levels of polycyclic aromatic hydrocarbons (PAHs) in soil and ambient air. The presence of other factors that might influence the exposure to PAHs was studied using a questionnaire. To evaluate the reliability of a single urinary 1-HP determination, measurements were repeated after 3 weeks for approximately 200 children. The mean urinary 1-HP content of the total study population was 2.06 nmol/l. This varied from 1.58 nmol/l in the reference area (Flevoland) to 2.71 nmol/l in the valley of the Geul. Only indoor sources of PAHs showed a small, positive association with urinary 1-HP. The urinary 1-HP concentrations of children from the valley of the Geul were higher (p < 0.01) and those of children from a suburb of Amsterdam were lower (p < 0.01) than those of children from the reference area. The possible ambient environment-related differences were probably too small to be detected in the variations of the intake of PAHs from the daily diet. The reliability of a single 1-HP measurement was low. Similar results were obtained with the creatinine-adjusted data. In one neighborhood built on coal-mine tailings, the urinary 1-HP content in children was weakly but positively associated with the PAH content in the upper soil layer of the garden of their homes. However, this association was not found for the children from the other neighborhood built on coal-mine tailings and with similar PAH levels in soil. PMID:8743441

  6. Manufacture of aromatic hydrocarbons from coal hydrogenation products

    SciTech Connect

    A.S. Maloletnev; M.A. Gyul'malieva

    2007-08-15

    The manufacture of aromatic hydrocarbons from coal distillates was experimentally studied. A flow chart for the production of benzene, ethylbenzene, toluene, and xylenes was designed, which comprised the hydrogen treatment of the total wide-cut (or preliminarily dephenolized) fraction with FBP 425{sup o}C; fractional distillation of the hydrotreated products into IBP-60, 60-180, 180-300, and 300-425{sup o}C fractions; the hydro-cracking of middle fractions for increasing the yield of gasoline fractions whenever necessary; the catalytic reform of the fractions with bp up to 180{sup o}C; and the extraction of aromatic hydrocarbons.

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

    PubMed

    Zasadowski, Arkadiusz; Wysocki, Adam

    2002-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants. They are found through environment in the air, in the soil, in water, in plants, and also in food. PAHs are formed during pyrolisis and the incomplete combustion of organic materials. PAHs can be man-made or occur naturally. They undergo metabolic activation after entering the mammalian cells to highly toxic reactive metabolite intermediates and can irreversibly damage cellular macromolecules (DNA, proteins, lipids). Polycyclic aromatic hydrocarbons represent a class of toxicological compounds which can create a variety of hazardous effects in vivo, including cytotoxicity, genotoxicity, immunotoxicity, teratogenicity and carcinogenesis described in present paper. PMID:12053482

  8. Polycyclic aromatic hydrocarbon oxidation during prostaglandin biosynthesis

    SciTech Connect

    Marnett, L.J.

    1981-08-10

    Polycyclic hydrocarbons and other xenobiotics are cooxygenated during the oxidative metabolism of polyunsaturated fatty acids. The products of polycyclic hydrocarbon cooxygenation depend upon the hydrocarbon but they appear to be formed by radical (or electron transfer) mechanisms. The cooxygenations are hydroperoxide-dependent oxidations catalyzed by peroxidases and may be triggered by enzymes which biosynthesize fatty acid hydroperoxides. Prostaglandin endoperoxide synthetase is the principal hydroperoxide-generating system which has been studied to date. The extent to which polyunsaturated fatty acid-dependent cooxygenation operates in vivo is uncertain but preliminary studies suggest it does occur.

  9. Determination of the aromatic hydrocarbon to total hydrocarbon ratio of mineral oil in commercial lubricants.

    PubMed

    Uematsu, Yoko; Suzuki, Kumi; Ogimoto, Mami

    2016-03-01

    A method was developed to determine the aromatic hydrocarbon to total hydrocarbon ratio of mineral oil in commercial lubricants; a survey was also conducted of commercial lubricants. Hydrocarbons in lubricants were separated from the matrix components of lubricants using a silica gel solid phase extraction (SPE) column. Normal-phase liquid chromatography (NPLC) coupled with an evaporative light-scattering detector (ELSD) was used to determine the aromatic hydrocarbon to total hydrocarbon ratio. Size exclusion chromatography (SEC) coupled with a diode array detector (DAD) and a refractive index detector (RID) was used to estimate carbon numbers and the presence of aromatic hydrocarbons, which supplemented the results obtained by NPLC/ELSD. Aromatic hydrocarbons were not detected in 12 lubricants specified for use for incidental food contact, but were detected in 13 out of 22 lubricants non-specified for incidental food contact at a ratio up to 18%. They were also detected in 10 out of 12 lubricants collected at food factories at a ratio up to 13%. The centre carbon numbers of hydrocarbons in commercial lubricants were estimated to be between C16 and C50. PMID:26730677

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

    SciTech Connect

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

    1996-02-01

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

  11. 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...

  12. 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...

  13. COHERENT ANTI-STOKES RAMAN SPECTROSCOPY OF POLYCYCLIC AROMATIC HYDROCARBONS

    EPA Science Inventory

    Coherent anti-Stokes Raman spectroscopy (CARS) was used to obtain Raman spectra of thirteen polycyclic aromatic hydrocarbons (PAHs) composed of between three and seven fused rings. The compounds were pumped in the resonance and preresonance regions to obtain the sensitivity neces...

  14. 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...

  15. Bioaccumulation of polycyclic aromatic hydrocarbons and metals in estuarine organisms

    SciTech Connect

    Not Available

    1989-01-01

    This standard makes use of four marine species, two fish and two shellfish, in a study to determine the bioavailability of two polycyclic aromatic hydrocarbons (PAHs) and two metals artificially incorporated in the sediment, and the metabolism and pharmacokinetics of the PAHs after uptake from the sediment or from food.

  16. Polycyclic aromatic hydrocarbons in workplace atmospheres: Occurrence and determination

    SciTech Connect

    Bjorseth, A.; Becher, G.

    1986-01-01

    This book examines the occupational health hazards imposed by polycyclic aromatic hydrocarbons (PAH). Topics considered include: PAH as occupational carcinogens; mode of formation; physical and chemical properties of PAH; sources and exposure; sampling of PAH in work atmospheres; analytical methods for airborne PAH; biological monitoring of PAH exposure; PAH in different workplace atmospheres; PAH profiles and proxy methods; and methods of analysis.

  17. Ambient aromatic hydrocarbon measurements at Welgegund, South Africa

    NASA Astrophysics Data System (ADS)

    Jaars, K.; Beukes, J. P.; van Zyl, P. G.; Venter, A. D.; Josipovic, M.; Pienaar, J. J.; Vakkari, V.; Aaltonen, H.; Laakso, H.; Kulmala, M.; Tiitta, P.; Guenther, A.; Hellén, H.; Laakso, L.; Hakola, H.

    2014-07-01

    Aromatic hydrocarbons are associated with direct adverse human health effects and can have negative impacts on ecosystems due to their toxicity, as well as indirect negative effects through the formation of tropospheric ozone and secondary organic aerosol, which affect human health, crop production and regional climate. Measurements of aromatic hydrocarbons were conducted at the Welgegund measurement station (South Africa), which is considered to be a regionally representative background site. However, the site is occasionally impacted by plumes from major anthropogenic source regions in the interior of South Africa, which include the western Bushveld Igneous Complex (e.g. platinum, base metal and ferrochrome smelters), the eastern Bushveld Igneous Complex (platinum and ferrochrome smelters), the Johannesburg-Pretoria metropolitan conurbation (> 10 million people), the Vaal Triangle (e.g. petrochemical and pyrometallurgical industries), the Mpumalanga Highveld (e.g. coal-fired power plants and petrochemical industry) and also a region of anticyclonic recirculation of air mass over the interior of South Africa. The aromatic hydrocarbon measurements were conducted with an automated sampler on Tenax-TA and Carbopack-B adsorbent tubes with heated inlet for 1 year. Samples were collected twice a week for 2 h during daytime and 2 h during night-time. A thermal desorption unit, connected to a gas chromatograph and a mass selective detector was used for sample preparation and analysis. Results indicated that the monthly median (mean) total aromatic hydrocarbon concentrations ranged between 0.01 (0.011) and 3.1 (3.2) ppb. Benzene levels did not exceed the local air quality standard limit, i.e. annual mean of 1.6 ppb. Toluene was the most abundant compound, with an annual median (mean) concentration of 0.63 (0.89) ppb. No statistically significant differences in the concentrations measured during daytime and night-time were found, and no distinct seasonal patterns were observed. Air mass back trajectory analysis indicated that the lack of seasonal cycles could be attributed to patterns determining the origin of the air masses sampled. Aromatic hydrocarbon concentrations were in general significantly higher in air masses that passed over anthropogenically impacted regions. Inter-compound correlations and ratios gave some indications of the possible sources of the different aromatic hydrocarbons in the source regions defined in the paper. The highest contribution of aromatic hydrocarbon concentrations to ozone formation potential was also observed in plumes passing over anthropogenically impacted regions.

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

    NASA Astrophysics Data System (ADS)

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

    1992-04-01

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

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

    SciTech Connect

    Marinov, N.M.; Pitz, W.J.; Westbrook, C.K.; Vincitore, A.M.; Castaldi, M.J.; Senkan, S.M.; Melius, C.F.

    1998-07-01

    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.

  20. Biodegradation of aliphatic vs. aromatic hydrocarbons in fertilized arctic soils

    USGS Publications Warehouse

    Braddock, J.F.

    1999-01-01

    A study was carried out to test a simple bioremediation treatment strategy in the Arctic and analyze the influence of fertilization the degradation of aliphatic and aromatic hydrocarbons, e.g., pristine, n-tetradecane, n-pentadecane, 2-methylnaphthalene, naphthalene, and acenaphthalene. The site was a coarse sand pad that once supported fuel storage tanks. Diesel-range organics concentrations were 250-860 mg/kg soil at the beginning of the study. Replicate field plots treated with fertilizer yielded final concentrations of 0, 50, 100, or 200 mg N/kg soil. Soil pH and soil-water potentials decreased due to fertilizer application. The addition of fertilizer considerably increased soil respiration potentials, but not the populations of microorganisms measured. Fertilizer addition also led to ??? 50% loss of measured aliphatic and aromatic hydrocarbons in surface and subsurface soils. For fertilized plots, hydrocarbon loss was not associated with the quantity of fertilizer added. Losses of aliphatic hydrocarbons were ascribed to biotic processes, while losses of aromatic hydrocarbons were due to biotic and abiotic processes.

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

    PubMed

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

    2012-10-18

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

  2. SOLUBILITY BEHAVIOR OF THREE AROMATIC HYDROCARBONS IN DISTILLED WATER AND NATURAL SEAWATER

    EPA Science Inventory

    The solubilities of three aromatic hydrocarbons were determined at 25 C. in natural seawater and distilled water. Saturation was achieved by equilibration of water and an excess of hydrocarbon by mechanical agitation. All three hydrocarbons, toluene, acenaphthene, and pyrene, wer...

  3. Hydrocarbon analogues of boron clusters--planarity, aromaticity and antiaromaticity.

    PubMed

    Zhai, Hua-Jin; Kiran, Boggavarapu; Li, Jun; Wang, Lai-Sheng

    2003-12-01

    An interesting feature of elemental boron and boron compounds is the occurrence of highly symmetric icosahedral clusters. The rich chemistry of boron is also dominated by three-dimensional cage structures. Despite its proximity to carbon in the periodic table, elemental boron clusters have been scarcely studied experimentally and their structures and chemical bonding have not been fully elucidated. Here we report experimental and theoretical evidence that small boron clusters prefer planar structures and exhibit aromaticity and antiaromaticity according to the Hückel rules, akin to planar hydrocarbons. Aromatic boron clusters possess more circular shapes whereas antiaromatic boron clusters are elongated, analogous to structural distortions of antiaromatic hydrocarbons. The planar boron clusters are thus the only series of molecules other than the hydrocarbons to exhibit size-dependent aromatic and antiaromatic behaviour and represent a new dimension of boron chemistry. The stable aromatic boron clusters may exhibit similar chemistries to that of benzene, such as forming sandwich-type metal compounds. PMID:14608377

  4. Metabolic Pathways for Degradation of Aromatic Hydrocarbons by Bacteria.

    PubMed

    Ladino-Orjuela, Guillermo; Gomes, Eleni; da Silva, Roberto; Salt, Christopher; Parsons, John R

    2016-01-01

    The aim of this review was to build an updated collection of information focused on the mechanisms and elements involved in metabolic pathways of aromatic hydrocarbons by bacteria. Enzymes as an expression of the genetic load and the type of electron acceptor available, as an environmental factor, were highlighted. In general, the review showed that both aerobic routes and anaerobic routes for the degradation of aromatic hydrocarbons are divided into two pathways. The first, named the upper pathways, entails the route from the original compound to central intermediate compounds still containing the aromatic ring but with the benzene nucleus chemically destabilized. The second, named the lower pathway, begins with ring de-aromatization and subsequent cleavage, resulting in metabolites that can be used by bacteria in the production of biomass. Under anaerobic conditions the five mechanisms of activation of the benzene ring described show the diversity of chemical reactions that can take place. Obtaining carbon and energy from an aromatic hydrocarbon molecule is a process that exhibits the high complexity level of the metabolic apparatus of anaerobic microorganisms. The ability of these bacteria to express enzymes that catalyze reactions, known only in non-biological conditions, using final electron acceptors with a low redox potential, is a most interesting topic. The discovery of phylogenetic and functional characteristics of cultivable and noncultivable hydrocarbon degrading bacteria has been made possible by improvements in molecular research techniques such as SIP (stable isotope probing) tracing the incorporation of (13)C, (15)N and (18)O into nucleic acids and proteins. Since many metabolic pathways in which enzyme and metabolite participants are still unknown, much new research is required. Therefore, it will surely allow enhancing the known and future applications in practice. PMID:26613990

  5. Ambient aromatic hydrocarbon measurements at Welgegund, South Africa

    NASA Astrophysics Data System (ADS)

    Jaars, K.; Beukes, J. P.; van Zyl, P. G.; Venter, A. D.; Josipovic, M.; Pienaar, J. J.; Vakkari, V.; Aaltonen, H.; Laakso, H.; Kulmala, M.; Tiitta, P.; Guenther, A.; Hellén, H.; Laakso, L.; Hakola, H.

    2014-02-01

    Aromatic hydrocarbons are associated with direct adverse human health effects and can have negative impacts on ecosystems due to their toxicity, as well as indirect negative effects through the formation of tropospheric ozone and secondary organic aerosol that affect human health, crop production and regional climate. Measurements were conducted at the Welgegund measurement station (South Africa) that is considered to be a regionally representative background site. However, the site is occasionally impacted by plumes from major anthropogenic source regions in the interior of South Africa, which include the western Bushveld Igneous Complex (e.g. platinum, base metal and ferrochrome smelters), the eastern Bushveld Igneous Complex (platinum and ferrochrome smelters), the Johannesburg-Pretoria metropolitan conurbation (>10 million people), the Vaal Triangle (e.g. petrochemical and pyrometallurgical industries), the Mpumalanga Highveld (e.g. coal-fired power plants and petrochemical industry) and also a region of anti-cyclonic recirculation of air mass over the interior of South Africa. The aromatic hydrocarbon measurements were conducted with an automated sampler on Tenax-TA and Carbopack-B adsorbent tubes with heated inlet for one year. Samples were collected twice a week for two hours during daytime and two hours during night-time. A thermal desorption unit, connected to a gas chromatograph and a mass selective detector was used for sample preparation and analysis. Results indicated that the monthly median total aromatic hydrocarbon concentrations ranged between 0.01 to 3.1 ppb. Benzene levels did not exceed local air quality standards. Toluene was the most abundant species, with an annual median concentration of 0.63 ppb. No statistically significant differences in the concentrations measured during daytime and night-time were found and no distinct seasonal patterns were observed. Air mass back trajectory analysis proved that the lack of seasonal cycles could be attributed to patterns determining the origin of the air masses sampled. Aromatic hydrocarbon concentrations were in general significantly higher in air masses that passed over anthropocentrically impacted regions. Interspecies correlations and ratios gave some indications of the possible sources for the different aromatic hydrocarbons in the source regions defined in the paper. The highest contribution of aromatic hydrocarbon concentrations to ozone formation potential was also observed in plumes passing over anthropocentrically impacted regions.

  6. Ambient aromatic hydrocarbon measurements at Welgegund, South Africa

    SciTech Connect

    Jaars, K.; Beukes, J. P.; van Zyl, P. G.; Venter, A. D.; Josipovic, M.; Pienaar, J. J.; Vakkari, Ville; Aaltonen, H.; Laakso, H.; Kulmala, M.; Tiitta, P.; Guenther, Alex B.; Hellen, H.; Laakso, L.; Hakola, H.

    2014-07-11

    Aromatic hydrocarbons are associated with direct adverse human health effects and can have negative impacts on ecosystems due to their toxicity, as well as indirect negative effects through the formation of tropospheric ozone and secondary organic aerosol that affect human health, crop production and regional climate. Measurements were conducted at the Welgegund measurement station (South Africa) that is considered to be a regionally representative background site. However, the site is occasionally impacted by plumes from major anthropogenic source regions in the interior of South Africa, which include the western Bushveld Igneous Complex (e.g. platinum, base metal and ferrochrome smelters), the eastern Bushveld Igneous Complex (platinum and ferrochrome smelters), the Johannesburg-Pretoria metropolitan conurbation (>10 million people), the Vaal Triangle (e.g. petrochemical and industries), the Mpumalanga Highveld (e.g. coal-fired power plants and petrochemical industry) and also a region of anti-cyclonic recirculation of air mass over the interior of South Africa. The aromatic hydrocarbon measurements were conducted with an automated sampler on Tenax-TA and Carbopack-B adsorbent tubes with heated inlet for one year. Samples were collected twice a week for two hours during daytime and two hours 1 during night-time. A thermal desorption unit, connected to a gas chromatograph and a mass 2 selective detector was used for sample preparation and analysis. Results indicated that the 3 monthly median total aromatic hydrocarbon concentrations ranged between 0.01 to 3.1 ppb. 4 Benzene levels did not exceed local air quality standards. Toluene was the most abundant 5 species, with an annual median concentration of 0.63 ppb. No statistically significant 6 differences in the concentrations measured during daytime and night-time were found and no distinct seasonal patterns were observed. Air mass back trajectory analysis proved that the lack of seasonal cycles could be attributed to patterns determining the origin of the air masses sampled. Aromatic hydrocarbon concentrations were in general significantly higher in air masses that passed over anthropocentrically impacted regions. Interspecies correlations and ratios gave some indications of the possible sources for the different aromatic hydrocarbons in the source regions defined in the paper. The highest contribution of aromatic hydrocarbon concentrations to ozone formation potential was also observed in plumes passing over anthropocentrically impacted regions.

  7. Spectrally Dominant Aromatic Hydrocarbon Compounds on Titan (Invited)

    NASA Astrophysics Data System (ADS)

    Clark, R. N.; Pearson, N.; Brown, R. H.; Cruikshank, D. P.; Barnes, J. W.; Jaumann, R.; Soderblom, L. A.; Rodriguez, S.; Le Mouélic, S.; Lunine, J. I.; Sotin, C.; Baines, K. H.; Buratti, B. J.; Nicholson, P. D.; Nelson, R.; Stephan, K.

    2010-12-01

    The surface composition of Titan is still shrouded in mystery. While some compounds have been identified and mapped on Titan's surface, like liquid ethane + methane lakes, and benzene, the compounds responsible for the main spectral properties have remained elusive (Clark et al, 2010, JGR in press). Titan's surface is seen in the near infrared in only a few spectral windows, near 0.94, 1.1, 1.3, 1.6, 2.0, 2.68-2.78, and 4.9-5.1 microns in the Cassini Visual and Infrared Mapping Spectrometer (VIMS) spectral range. The apparent reflectance in these windows generally decreases with increasing wavelength except the 2.7 and 5-micron windows which are similar in level. The decrease has led researchers to infer a number of compounds, responsible for the observed decreasing spectral shape; the most common being water ice. But ice is incompatible with the 2.78/2.68 micron I/F ratio. Many organic compounds have absorptions not seen on Titan, eliminating them as possible major components at the surface. In a broad survey of the reflectance properties of organic compounds we have found that the closest spectral matches to the Titan spectrum is best explained by abundant aromatic hydrocarbons Aromatic hydrocarbons are compatible with all the ratios of reflectances observed through the atmospheric windows, including the 2.68 and 2.78 micron windows. Clark et al. (2010) found a 5.01-micron absorption in some Titan spectra but could not identify a compound. We find that the polycyclic aromatic hydrocarbon (PAH) coronene, consisting of 6 benzene rings matches that feature. Coronene is also a naturally occurring mineral on Earth, known as karpatite. Combinations of PAHs such as coronene, phenanthene (C14H12), pentacene (C22H14) and other aromatic hydrocarbons like indole (C8H7N) match the overall spectral structure of Titan spectra, Further, subtle changes in spectral diversity shown by Clark et al. in the 5-micron window can be explained by variations in the relative abundances of the aromatic hydrocarbons. Indole has a 1.5 micron band that can explain the feature observed in DISR spectra of Titan's surface. Titan's surface seems dominated by aromatic hydrocarbon.

  8. Polycyclic aromatic hydrocarbons in Saccoglossus kowalewskyi (Agassiz)

    NASA Astrophysics Data System (ADS)

    Carey, D. A.; Farrington, J. W.

    1989-08-01

    Hydrocarbon extracts were analyzed from Saccoglossus kowalewskyi, a deposit-feeding enteropneust worm, and from surface sediments from Cape Cod, MA. Worms were held in experimental aquaria in sieved sediments and flowing seawater for four months and then fed sediments mixed with creosote, lampblack or clean sediment for two weeks as analogues of sediments containing degraded oil and pyrogenic compounds. Worms from all treatments contained polyaromatic hydrocarbons (PAHs) in amounts and composition that indicate that the worms were contaminated with weathered No. 2 fuel oil before our experimental treatment and that the contamination persisted for four months in clean conditions. The contamination was not detected in the clean sediments used in the experiment. The worms accumulated steroid transformation products in greater abundance than the odd chain n-alkanes that dominated the sediment extractions. This may indicate selective assimilation of algal detritus and microbial products over salt marsh detritus. Worms, actively feeding during the experiment, contained 1-3 × 10 -6 g g -1 dry weight of unknown brominated compounds which were not detected in the sediments. These compounds are similar to bromopyrroles found elsewhere in enteropneusts, polychaetes and bacteria and may cause substantial interference in analyses for some industrial pollutants.

  9. Phenalenyl-based open-shell polycyclic aromatic hydrocarbons.

    PubMed

    Kubo, Takashi

    2015-02-01

    The phenalenyl radical is a polycyclic aromatic hydrocarbon (PAH) radical. Owing to its widely distributed spin structure, phenalenyl is relatively stable compared to other hydrocarbon radicals and has been studied from the viewpoint of its application to electroconductive and magnetic materials. In addition, a strong intermolecular spin-spin coupling nature is another feature of phenalenyl. This account summarizes my studies so far into PAH radicals containing the phenalenyl scaffold in terms of their amphoteric redox properties and singlet biradical character, which strongly rely on the characteristic electronic structure, that is, non-bonding character and sixfold symmetry of a singly occupied molecular orbital of the phenalenyl radical. PMID:25345729

  10. Biogenic Contributions to Aromatic Hydrocarbon Production over Continental North America

    NASA Astrophysics Data System (ADS)

    Sive, B. C.; Russo, R.; Zhou, Y.; Swarthout, R.; Hart, A.

    2011-12-01

    A comprehensive suite of temporally and vertically resolved volatile organic compound (VOC) measurements were conducted at the Boulder Atmospheric Observatory (BAO) in Erie, Colorado from 18 February to 13 March 2011 as part of the Nitrogen, Aerosol Composition, and Halogens on a Tall Tower (NACHTT) campaign. Specifically, this work investigates and quantifies the contribution of monoterpene oxidation to the secondary production of aromatic hydrocarbons and secondary organic aerosol (SOA) precursor gases. To date, this area of research has been largely unexplored; however, recent results from laboratory experiments have suggested that biogenic VOC (BVOC) oxidation should be considered as an important source of aromatic hydrocarbons, especially in rural and remote environments. The VOC measurements conducted during the NACHTT campaign provide diurnally and vertically resolved speciated monoterpene data over mid-latitude North America. New insight on biogenic emissions, their subsequent chemical transformations and influences on oxidant cycling will be explored.

  11. Incremental aerosol reactivity: Application to aromatic and biogenic hydrocarbons

    SciTech Connect

    Griffin, R.J.; Cocker, D.R. III; Seinfeld, J.H. )

    1999-07-15

    The concept of incremental aerosol reactivity is introduced, and the incremental aerosol reactivities of a number of important anthropogenic and biogenic hydrocarbons are investigated for four ambient scenarios. The incremental aerosol reactivity, defined as a change in the secondary organic aerosol mass produced (in [micro]g m[sup [minus]3]) per unit change of parent organic reacted (in ppb), is a measure of the aerosol-forming capability of a given parent organic in a prescribed mixture of other organic compounds. The base-case scenario is a mixture of both aromatic and biogenic organics. Reactivity values depend on the choice of the initial organic mixture, so cases are also examined in which all biogenic hydrocarbon concentrations are set to zero and all aromatic concentrations are set to zero. The influence of additional organic aerosol is also investigated.

  12. Scavenging of polycyclic aromatic hydrocarbons from the atmosphere

    NASA Astrophysics Data System (ADS)

    Skrdlikova, L.; Kohoutek, J.; Klánová, J.

    2009-04-01

    Scavenging of polycyclic aromatic hydrocarbons from the atmosphere Lenka Škrdlíková, Jiří Kohoutek, Jana Klánová An important process affecting a fate of persistent organic pollutants in the environment is their wet removal from the atmosphere. An efficiency of the wet deposition depends on the properties of compounds, their partitioning between the gas and particulate phases, type of precipitation and meteorological conditions. Atmospheric concentrations of polycyclic aromatic hydrocarbons (PAHs) were measured in the gas and particle phases prior and after the precipitation event. During the precipitation, snow or rain was sampled by a wet sampler and the particle-bound fraction was separated from the dissolved fraction. Scavenging coefficients were determined as a ratio of the air and rain concentrations. Significant differences in the efficiency of scavenging processes were found between the snow and rain precipitations under specific meteorological situation. Keywords - scavenging, precipitation, scavenging coefficient, partitioning

  13. THE INFRARED SPECTROSCOPY OF NEUTRAL POLYCYCLIC AROMATIC HYDROCARBON CLUSTERS

    SciTech Connect

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

    2013-10-10

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

  14. Polycyclic aromatic hydrocarbons in some grounded coffee brands.

    PubMed

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

    2013-08-01

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

  15. Electron energy loss spectra of polycyclic aromatic hydrocarbons

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

    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.

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

    USGS Publications Warehouse

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

    1996-01-01

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

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

    PubMed

    d'Hendecourt, L; Ehrenfreund, P

    1997-01-01

    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

  18. Ambient air pollution by aromatic hydrocarbons in Algiers

    NASA Astrophysics Data System (ADS)

    Kerbachi, Rabah; Boughedaoui, Ménouèr; Bounoua, Lahouari; Keddam, Malika

    The analysis of the C 6-C 16 semi-volatile organic compounds reveals the presence of numerous aromatic hydrocarbons in the ambient air of Algiers. Three representative sites were chosen for sample collection at roadside, urban background and semi-rural areas. The following major monocyclic aromatic hydrocarbons were found: benzene, toluene, ethylbenzene, ( m, p)- and o-xylene, also referred to as BTEX. Near the road traffic, benzene and toluene mean concentrations were 27 and 39 μg m -3, respectively, with benzene concentration values higher than 40 μg m -3 often observed. At the urban site, the benzene concentration often exceeds the European regulatory limit of 10 μg m -3 while the compositional ratios of toluene to benzene and ( m- p) xylene to ethylbenzene are within the typical range of values observed in urban atmospheres worldwide. The seasonal variation indicates a decrease in concentration during summer of the reactive o-xylene compound. It is suggested that Algiers' source of high-level air pollution by aromatic hydrocarbons is related to car traffic emissions.

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

    SciTech Connect

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

    2013-07-01

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

  20. QSARs for aromatic hydrocarbons at several trophic levels.

    PubMed

    Di Marzio, Walter; Saenz, Maria Elena

    2006-04-01

    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

  1. Selective conversion of aromatic hydrocarbons to fine chemical intermediates

    SciTech Connect

    Zong, Z.; Zhang, W.; Jiang, Q.; Wei, X.

    1997-12-31

    The use of aromatic hydrocarbons derived from coal liquids including coal tar is an important process for nonfuel utilization of coal. Many fine chemical intermediates, which can be used to synthesize dyes, agricultural chemicals, medicines, paints, engineering plastics and so on, can be obtained by the addition and conversion of some functional groups on aromatic rings. Therefore, selective conversion of aromatic hydrocarbons to fine chemical intermediates has been paid great attention. Selective photobromination, dehydrogenation and oxidation of some arenes and hydrolysis of the resulting bromomethylarenes were investigated. The results show that under nitrogen atmosphere, side-chain methyl groups on the aromatic ring can be brominated selectively with visible light and N-bromosuccinimide (NBS) in benzene at room temperature. Fluorene and {alpha},{omega}-diphenylalkanes are also photobrominated, whereas tetralin and 9,10-dihydrophenanthrene are mainly dehydrogenated under the same reaction condition. Acenaphthene and 9,10-dihydroanthracene are first dehydrogenated and then photobrominated. The resulting bromomethylarenes can be converted to the corresponding hydroxymethylarenes in alkaline or acidic aqueous solutions. Under an oxygen atmosphere, methylarenes are converted to carboxylic arenes with visible light and NBS in benzene at room temperature. The related reaction mechanisms are discussed.

  2. Lymphocyte aromatic hydrocarbon responsiveness in acute leukemia of childhood

    SciTech Connect

    Blumer, J.L.; Dunn, R.; Esterhay, M.D.; Yamashita, T.S.; Gross, S.

    1981-12-01

    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.

  3. The high-temperature oxidation of aromatic hydrocarbons

    NASA Technical Reports Server (NTRS)

    Brezinsky, K.

    1986-01-01

    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.

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

    SciTech Connect

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

    2009-02-15

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

  5. Metabolism of nitropolycyclic aromatic hydrocarbons by human intestinal microflora

    SciTech Connect

    Cerniglia, C.E.; Howard, P.C.; Fu, P.P.; Franklin, W.

    1984-08-30

    Anaerobic bacterial suspensions from human and rat feces and intestinal contents, and pure cultures of anaerobic bacteria metabolized 1-nitropyrene and 6-nitrobenzo(a)pyrene to 1-aminopyrene and 6-aminobenzo(a)pyrene, respectively. The metabolites were isolated by reversed-phase high performance liquid chromatography and identified by comparison of their chromatographic and mass spectral properties with those of authentic compounds. The results suggest that anaerobic intestinal bacteria could play a significant role in the metabolism of potentially carcinogenic nitropolycyclic aromatic hydrocarbons. 28 references, 4 figures, 1 table.

  6. Synthesis of polycyclic aromatic hydrocarbons in He nanodroplets

    NASA Astrophysics Data System (ADS)

    Gschliesser, D.; Ferreira da Silva, F.; Bartl, P.; Denifl, S.; Scheier, P.

    2012-11-01

    Here we report the first mass spectrometric study of the synthesis of larger polycyclic aromatic hydrocarbon molecules (PAHs) out of weakly bound triphenylene agglomerates in cold helium droplets upon electron ionization. A highly abundant single reaction product is observed which indicates an extremely efficient and selective process. We propose that the synthesis of large molecules like fullerenes in interstellar clouds may proceed via similar reactions. Future work on different PAHs like benz[a]anthracene or chrysene will give more insight into this fascinating synthesis process.

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

    SciTech Connect

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

    2009-02-15

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

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

    PubMed Central

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

    2014-01-01

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

  9. Extraction Techniques for Polycyclic Aromatic Hydrocarbons in Soils

    PubMed Central

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

    2010-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Deamer, D. W.

    1992-01-01

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

  11. Polynuclear aromatic hydrocarbons in oyster tissue around three coastal marinas

    SciTech Connect

    Marcus, J.M.; Stokes, T.P.

    1985-12-01

    Marinas present the potential for introduction of various pollutants into the surrounding waters such as coliform bacteria, primary pathogens, heavy metals, and petroleum hydrocarbons. Little data have been presented specifically addressing the effects of recreational marinas on petroleum hydrocarbon levels or, for that matter, other constituent levels in oysters near those marinas. In order to obtain such data, a comprehensive assessment of water and oyster quality around three coastal marinas was conducted by the South Carolina Department of Health and Environmental control (SCDHEC) during 1983. Polynuclear aromatic hydrocarbons (PAH) were selected as the petroleum hydrocarbon fraction of interest since they are mainly of pyrogenic origin; have been shown to be the most toxic/carcinogenic fraction of oil; have been shown to affect the respiration and heart rates of mussels; and have been shown to be linked to neoplasia in clams and proliferative disorders in mussels. C. virginica was chosen as the mollusc of interest because of its widespread distribution in the estuaries of South Carolina, its importance as an economic and recreational resource, and its suitability as a sentinel organism for monitoring coastal pollution.

  12. Polycyclic Aromatic Hydrocarbons as Plausible Prebiotic Membrane Components

    NASA Astrophysics Data System (ADS)

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

    2012-08-01

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

  13. Polycyclic aromatic hydrocarbons as plausible prebiotic membrane components.

    PubMed

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

    2012-08-01

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

  14. Relative rates of coke formation from hydrocarbons in steam cracking of naphtha: 3. Aromatic hydrocarbons

    SciTech Connect

    Kopinke, F. . Section of Remediation Research); Zimmermann, G. ); Reyniers, G.C.; Froment, G.F. )

    1993-11-01

    Relative rate constants of coke formation (k) from 18 aromatic hydrocarbons during steam cracking of naphtha at 810 C were determined by application of [sup 14]C-labeled compounds. Benzene is a poor coke precursor (k = 0.3), whereas polycyclic structures like acenaphthylene, anthracene, and chrysene have a high coking potential in the pyrolysis reactor (k = 4.5--6) as well as in the TLE section (k = 12--30). The relation between structure and coke formation rate of aromatic hydrocarbons can be interpreted on the basis of their reactivity in radical reactions. Constituents of the fuel fraction ([ge] C[sub 9]) derived from nonaromatic feed components are more efficient in the TLE fouling than those stemming from benzene derivatives.

  15. Formation of polycyclic aromatic hydrocarbons in circumstellar envelopes

    NASA Technical Reports Server (NTRS)

    Frenklach, Michael; Feigelson, Eric D.

    1989-01-01

    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.

  16. Secondary organic aerosol formation from the oxidation of polycyclic aromatic hydrocarbons with two aromatic rings

    NASA Astrophysics Data System (ADS)

    Shakya, K. M.; Griffin, R. J.

    2007-12-01

    Polycyclic aromatic hydrocarbons (PAHs) are products of incomplete combustion and are ubiquitous in the environment. In the atmosphere, gas-phase reactions of PAHs with two aromatic rings with hydroxyl radicals (OH) lead to products that partition to the aerosol phase, forming secondary organic aerosol (SOA). The main objective of this study is to quantify the conversion of gas-phase PAHs with two aromatic rings into particle-phase species through the SOA yield. Eight experiments were conducted on each of the following PAHs: naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, acenaphthalene, acenaphthylene, and fluorene. Experiments were performed in a 9-m3 Teflon chamber, at an initial hydrocarbon to nitric oxide ratio of approximately five, and using hydrogen peroxide as the OH source. The experiments were initiated by illuminating germicidal lamps to drive photochemical reactions and were terminated when the SOA formation reached a plateau. During the experiments, PAH mixing ratios, aerosol particle size distributions and number concentrations, oxides of nitrogen mixing ratios, and ozone mixing ratios were monitored by a gas chromatograph with a flame ionization detector, a scanning mobility particle sizer spectrometer, a chemiluminescence analyzer, and a photometric analyzer, respectively. Results indicate SOA yields ranging from 0.02 to 0.12 over an organic aerosol mass concentration range of 2 to 15 μ g m-3. Peak aerosol mode diameters were in the range of 60 to 80 nm. An attempt to determine the relationship between yields and PAH structure will be made.

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

    USGS Publications Warehouse

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

    1998-01-01

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

  18. Polycyclic aromatic hydrocarbons in clams Ruditapes decussatus (Linnaeus, 1758).

    PubMed

    Barreira, Luísa A; Mudge, Stephen M; Bebianno, Maria J

    2007-02-01

    The concentration of sixteen individual polycyclic aromatic hydrocarbons (PAHs) was measured in the clam Ruditapes decussatus whole soft tissues from several places of the Ria Formosa lagoon (Portugal). Total PAH (tPAH) concentrations were higher in the summer (August) and winter (January) than in the other months and the distribution pattern of the individual PAHs was generally dominated by the 4 aromatic ring PAHs, followed by the 2 + 3 aromatic rings PAHs. Benzo[a]anthracene and acenaphthene were the most representative PAHs of the two fractions. Principal components analysis (PCA) revealed that, in the Ria Formosa, seasonal variations are more important than spatial variations, due to changes in PAH source. These sources ranged from petrogenic to pyrolytic or a mixture of both. The origin of clam PAHs was also assessed by partial least squares (PLS) analysis using nineteen different PAH signatures, taken from the literature. It was possible to identify boat traffic, especially in the summer, as one of the most relevant PAH sources to the Ria Formosa. The influence of boat traffic was revealed by several signatures including diesel soot, oil and weathered oil and a mixture of different individual PAHs usually found in harbour sediments. Other relevant sources included combustion of organic matter such as forest fires and diverse domestic activities, occurring mainly in the summer. Most of the clams were considered safe for human consumption, except for some point samples, which presented unusually high PAH concentrations, suggesting the need for a regular survey of PAHs in clam tissues. PMID:17285162

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

    NASA Astrophysics Data System (ADS)

    Zhang, Hongliang; Ying, Qi

    2012-08-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2004-09-01

    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.

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

    DOEpatents

    Reilly, Peter T. A.

    2004-10-19

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

    Substitution of methyl groups onto the aromatic ring determines the SOA formation from the aromatic hydrocarbon precursor. This study links the number of methyl groups on the aromatic ring to SOA formation from aromatic hydrocarbons photooxidation under low NOx conditions (HC / NO > 10 ppb C : ppb). Aromatic hydrocarbons with increasing numbers of methyl groups are systematically studied. SOA formation from pentamethylbenzene and hexamethylbenzene are reported for the first time. A decreasing SOA yield with increasing number of methyl groups is observed. Linear trends are found in both f44 vs. f43 and O / C vs. H / C for SOA from aromatic hydrocarbons with zero to six methyl groups. An SOA oxidation state predictive method based on benzene is used to examine the effect of added methyl groups on aromatic oxidation under low NOx conditions. Further, the impact of methyl group number on density and volatility of SOA from aromatic hydrocarbons is explored. Finally, a mechanism for methyl group impact on SOA formation is suggested. Overall, this work suggests as more methyl groups are attached on the aromatic ring, SOA products from these aromatic hydrocarbons become less oxidized per mass/carbon.

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

    PubMed

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

    1999-01-01

    Heterocyclic aromatic amines (HAA) and polycyclic aromatic hydrocarbons (PAH) are mutagens and animal carcinogens sometimes formed when foods are heated or processed. Determining their role in cancer etiology depends on comparing human exposures and determining any significant dose-related effects. Chemical analysis of foods shows that flame-grilling can form both PAH and HAA, and that frying forms predominantly HAA. With detection limits of about 0.1 ng/g, amounts found in commercially processed or restaurant foods range from 0.1 to 14 ng/g for HAA, and levels of PAH up to 1 ng/g in a liquid smoke flavoring. Laboratory fried samples have greater amounts of PAH, up to 38 ng/g in hamburgers, and high levels of HAA, over 300 ng/g, are measured in grilled chicken breast. Understanding the processing conditions that form PAH and HAA can lead to methods to greatly reduce their occurrence in processed foods. PMID:10335376

  4. CHEMICAL INDUCTION OF TUMORS IN OYSTERS BY A MIXTURE OF AROMATIC AND CHLORINATED HYDROCARBONS, AMINES, AND METALS

    EPA Science Inventory

    Tumors were induced in eastern oysters (Crassotrea virginica) by a mixture f aromatic hydrocarbons, an aromatic amine, polychlori-nated biphenyls, chlorinated hydrocarbons, a nitrosoamine and heavy metals. idney and nteric tumors developed in oysters following exposure to a mixtu...

  5. Isolation and screening of black fungi as degraders of volatile aromatic hydrocarbons.

    PubMed

    Isola, Daniela; Selbmann, Laura; de Hoog, G Sybren; Fenice, Massimiliano; Onofri, Silvano; Prenafeta-Boldú, Francesc X; Zucconi, Laura

    2013-06-01

    Black fungi reported as degraders of volatile aromatic compounds were isolated from hydrocarbon-polluted sites and indoor environments. Several of the species encountered are known opportunistic pathogens or are closely related to pathogenic species causing severe mycoses, among which are neurological infections in immunocompetent individuals. Given the scale of the problem of environmental pollution and the phylogenetic relation of aromate-degrading black fungi with pathogenic siblings, it is of great interest to select strains able to mineralize these substrates efficiently without any risk for public health. Fifty-six black strains were obtained from human-made environments rich in hydrocarbons (gasoline car tanks, washing machine soap dispensers) after enrichment with some phenolic intermediates of toluene and styrene fungal metabolism. Based on ITS sequencing identification, the majority of the obtained isolates were members of the genus Exophiala. Exophiala xenobiotica was found to be the dominant black yeast present in the car gasoline tanks. A higher biodiversity, with three Exophiala species, was found in soap dispensers of washing machines. Strains obtained were screened using a 2,6-dichlorophenol-indophenol (DCPIP) assay, optimized for black fungi, to assess their potential ability to degrade toluene. Seven out of twenty strains tested were able to use toluene as carbon source. PMID:23475324

  6. Polycyclic aromatic hydrocarbons in the soils of Moscow

    NASA Astrophysics Data System (ADS)

    Belinskaya, E. A.; Zykova, G. V.; Semenov, S. Yu.; Finakov, G. G.

    2015-06-01

    The contents of polycyclic aromatic hydrocarbons (PAHs) in soil samples taken in the city of Moscow have been determined. A sixfold excess of the maximum permissible concentration (MPC) for benzo[ a]pyrene has been found in 66% of the studied samples; an excess of the European standard for benzo[ a]pyrene has been observed in 31% of the samples. The found weight fraction of benzo[ a]pyrene in soil samples varies in the range of 10-740 μg/kg. The content of the ecotoxicant in the soil increases from west to east. The total concentrations of 10 indicative PAH compounds in the soils of Moscow are usually lower than the European standard. An excess of the European standard by 2-6 times has been noted in the Southeastern, Eastern, and Central administrative districts of Moscow, with separate sites of high contamination up to 6118 μg/kg.

  7. [Exposure to polycyclic aromatic hydrocarbons (PAH) in rubber forming industry].

    PubMed

    Cirla, P E; Martinotti, I; Mossini, E; Tieghi, S; Antoniazzi, E; Galli, L; Pavesi, D; Fustinoni, S; Campo, L; Fo, V; Cirla, A M

    2007-01-01

    Among various chemical agents present at the workplaces in the rubber industry, a particular attention was adressed to the Polycyclic Aromatic Hydrocarbons (PAH) contained in oil and carbon black, but some questions regarding level of exposure are also controversially discussed. The literature reports that PAH may have irritant effects; moreover some of these have been recognized as probably or possibly carcinogenic to human by the International Agency for Research on Cancer, the European Union, and other institutions. In Lombardy, a study aimed to evaluate the occupational exposure in Benzo[b]fluorantene the rubber forming industry was planned during last two years. The results of environmental air monitoring (the 16 most relevant, according to the American Environmental Protection Agency, EPA) and biological monitoring (urinary 1-hydroxypyrene excretion) show that PAH exposure in these workers is not higher than that observed in other study regarding low level and acceptable exposure. PMID:18409687

  8. Adsorption and STM imaging of polycyclic aromatic hydrocarbons on graphene

    NASA Astrophysics Data System (ADS)

    Dappe, Y. J.; Andersen, M.; Balog, R.; Hornekær, L.; Bouju, X.

    2015-01-01

    The structural characterization of polycyclic aromatic hydrocarbon molecules adsorbed on graphene is of fundamental importance in view of the use of graphene or graphene nanoribbons for electronic applications. Before reaching this point, one has to determine the structure of the adsorbed molecules. Here, we study the case of benzene, coronene, and hexabenzocoronene on a graphene layer. First, the adsorption properties of single molecules are calculated using first-principles calculations at the level of density functional theory. We benefit from a recent scheme, particularly adapted for weakly adsorbed molecules, allowing us to precisely calculate the van der Waals contribution. Then, scanning tunneling microscopy (STM) is used to produce images of self-assembled molecules comparing different theoretical approaches to experimental observations. Finally, we consider the imaging of isolated molecules, and we show how the STM tip influences the molecule position by soft mechanical interaction during the scanning process.

  9. Shock-Induced Chemical Reactions of Polycyclic Aromatic Hydrocarbons

    NASA Astrophysics Data System (ADS)

    Elert, Mark; Zybin, Sergey; Revell, Shannon; White, Carter

    2006-03-01

    Polycyclic aromatic hydrocarbons (PAHs) have been found in the atmospheres of Jupiter and Titan, and also in meteorites, interplanetary dust, and circumstellar graphite grains. The ubiquity of these complex organic structures and their stability under extreme conditions make them a significant factor in discussions of brebiotic chemistry in the solar system. To study the shock-induced chemistry of PAHs under conditions appropriate for astrophysical impacts, molecular dynamics simulations have been carried out for solid naphthalene and anthracene using a reactive empirical potential. The major reaction channels for these two closely related compounds were found to be substantially different. Product distributions were also found to depend strongly on the orientation of the PAH crystal relative to the shock propagation direction.

  10. Palladium-catalyzed pentannulation of polycyclic aromatic hydrocarbons.

    PubMed

    Lütke Eversloh, Christian; Avlasevich, Yuri; Li, Chen; Müllen, Klaus

    2011-11-01

    We present a new and versatile one-step synthesis of a series of small molecular chromophores based on cyclopentannulated polycyclic aromatic hydrocarbons (PAH). Easily available pyrene, anthracene, and perylene bromides serve as starting materials for the reactions. The formation of the five-membered ring is achieved by the straightforward palladium(0)-catalyzed carbannulation with various substituted acetylenes. This approach is applicable either to single or multiple annulation procedures leading to hitherto inaccessible PAH topologies. According to the resulting products of the diverse reactions, a mechanistic explanation is proposed. UV/Vis absorption as well as cyclovoltammetric measurements were performed for characterization demonstrating the value of this annulation technique. Optical absorptions of up to 780 nm and absorption coefficients ranging from 8000 to 34,000 M(-1) cm(-1) were detected. PMID:21956345

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

    NASA Astrophysics Data System (ADS)

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

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

  12. Simulated transport of polycyclic aromatic hydrocarbons in artificial streams

    SciTech Connect

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

    1981-01-01

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

  13. Determination of polycyclic aromatic hydrocarbons in roasted coffee.

    PubMed

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

    2014-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Gatchell, M.; Stockett, M. H.; de Ruette, N.; Chen, T.; Giacomozzi, L.; Nascimento, R. F.; Wolf, M.; Anderson, E. K.; Delaunay, R.; Vizcaino, V.; Rousseau, P.; Adoui, L.; Huber, B. A.; Schmidt, H. T.; Zettergren, H.; Cederquist, H.

    2015-11-01

    A recent study of soft x-ray absorption in native and hydrogenated coronene cations, C24H12+m +m =0 -7 , led to the conclusion that additional hydrogen atoms protect (interstellar) polycyclic aromatic hydrocarbon (PAH) molecules from fragmentation [Reitsma et al., Phys. Rev. Lett. 113, 053002 (2014), 10.1103/PhysRevLett.113.053002]. The present experiment with collisions between fast (30-200 eV) He atoms and pyrene (C16H10+m + , m =0 , 6, and 16) and simulations without reference to the excitation method suggests the opposite. We find that the absolute carbon-backbone fragmentation cross section does not decrease but increases with the degree of hydrogenation for pyrene molecules.

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

    NASA Technical Reports Server (NTRS)

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

    1999-01-01

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

  16. INFRARED SPECTRA OF ISOLATED PROTONATED POLYCYCLIC AROMATIC HYDROCARBON MOLECULES

    SciTech Connect

    Knorke, Harald; Langer, Judith; Dopfer, Otto; Oomens, Jos

    2009-11-20

    Gas-phase infrared (IR) spectra of larger protonated polycyclic aromatic hydrocarbon molecules, H{sup +}PAH, have been recorded for the first time. The ions are generated by electrospray ionization and spectroscopically assayed by IR multiple-photon dissociation (IRMPD) spectroscopy in a Fourier transform ion cyclotron resonance mass spectrometer using a free electron laser. IRMPD spectra of protonated anthracene, tetracene, pentacene, and coronene are presented and compared to calculated IR spectra. Comparison of the laboratory IR spectra to an astronomical spectrum of the unidentified IR emission (UIR) bands obtained in a highly ionized region of the interstellar medium provides for the first time compelling spectroscopic support for the recent hypothesis that H{sup +}PAHs contribute as carriers of the UIR bands.

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

    SciTech Connect

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

    2009-09-03

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

  18. Phototoxicity of polycyclic aromatic hydrocarbons at varying light intensities

    SciTech Connect

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

    1994-12-31

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

  19. Magnetic instability and pair binding in aromatic hydrocarbon superconductors.

    PubMed

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

    2012-01-01

    Understanding magnetism and electron correlation in many unconventional superconductors is essential to explore mechanism of superconductivity. In this work, we perform a systematic numerical study of the magnetic and pair binding properties in recently discovered polycyclic aromatic hydrocarbon (PAH) superconductors including alkali-metal-doped picene, coronene, phenanthrene, and dibenzopentacene. The π-electrons on the carbon atoms of a single molecule are modelled by the one-orbital Hubbard model, and the energy difference [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

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

    PubMed

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

    2016-05-15

    Polycyclic aromatic hydrocarbons (PAHs) emerged as an important contaminant group in a gamut of processed food groups like dairy, nuts, herbs, beverages, meat products etc. Different cooking processes and processing techniques like roasting, barbecuing, grilling, smoking, heating, drying, baking, ohmic-infrared cooking etc. contribute towards its formation. The level of PAHs depends on factors like distance from heat source, fuel used, level of processing, cooking durations and methods, whereas processes like reuse, conching, concentration, crushing and storage enhance the amount of PAHs in some food items. This review paper provides insight into the impact of dietary intake of PAHs, its levels and formation mechanism in processed food items and possible interventions for prevention and reduction of the PAHs contamination. The gaps and future prospects have also been assessed. PMID:26776034

  1. Polynuclear aromatic hydrocarbons (PAHs) in fish from the Arabian Gulf

    SciTech Connect

    DouAbdul, A.A.Z.; Abaychi, J.K.; Al-Edanee, T.E.; Ghani, A.A.; Al-Saad, H.T.

    1987-03-01

    Emphasis has been placed upon the identification and qualification of compounds with potential adverse health effects on humans. Prominent among this group are polynuclear aromatic hydrocarbons (PAHs), several of which are known or suspected carcinogens. PAHs enter the marine environment from a variety of sources including petroleum pollution, industrial and domestic effluents, atmospheric particles, and biosynthesis by plants and microorganisms. Although one-third of the world's oil is produced around the Arabian Gulf, no detailed analysis have been conducted to determine PAHs in this region. Nevertheless, numerous investigations have shown the ability of marine organisms including fish to accumulation PAHs from solution or dispersion in seawater. When fish are harvested, a human health hazard may result. In the present communication, high performance liquid chromatography (HPLC) was used to identify and measure sixteen PAHs priority pollutants issued by US Environmental Protection Agency (EPA) in fourteen species of commercially significant fish from the NW Arabian Gulf.

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

    NASA Technical Reports Server (NTRS)

    Voit, G. M.

    1992-01-01

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

  3. Polycyclic Aromatic Hydrocarbons and Infrared Astrophysics with Spitzer

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

  4. Carcinogenic classification of polycyclic aromatic hydrocarbons through theoretical descriptors

    NASA Astrophysics Data System (ADS)

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

    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.

  5. Theoretical properties of polycyclic aromatic hydrocarbon clusters of astrophysical interest

    NASA Astrophysics Data System (ADS)

    Rapacioli, M.; Joblin, C.; Calvo, F.; Spiegelman, F.; Parneix, P.

    Polycyclic Aromatic Hydrocarbons (PAHs) have been proposed as the carriers of the aromatic infrared bands observed in many places of the interstellar medium. However the main difficulty faced by the PAH model is the identification of individual species. We have analyzed spectro-imagery data obtained with the camera CAM on board of the Infrared Space Observatory, applying the singular value decomposition method. This work (Rapacioli et al. (2005)) strongly suggests that PAHs are produced by photoevaporation of very small carbonaceous grains which could be PAH clusters. This result motivated the following theoretical work. We have performed a parallel tempering Monte Carlo search of the structures with lowest energy of PAH clusters ranging from two to thirty molecules (Rapacioli et al. (2005b)). We found evidence that stacking the PAH molecules generally yields the most stable structures. After some critical size, one-dimensional pattern is replaced by two and three-dimensional growth, again with small stacks as the building block. The collision of a PAH molecule with a PAH cluster has been studied. The resulting excited cluster can loose one or more molecules or relax through infrared emission. The competition between the IR emission rate and the evaporation rate calculated with a statistical method allows to characterize the astrophysical environments that are favourable to the PAH clusters growth.

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

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

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

    SciTech Connect

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

    2013-06-20

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

  9. Biodegradation of aromatic hydrocarbons by aquifer microorganisms under denitrifying conditions

    SciTech Connect

    Hutchins, S.R.; Sewell, G.W.; Kovacs, D.A.; Smith, G.A.

    1991-01-01

    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 uncontaminated and contaminated aquifer material, amended with nitrate, nutrients, and aromatic hydrocarbons, and incubated under a nitrogen atmosphere at 12 C. With uncontaminated core material, there was no observable lag period prior to removal of toluene whereas 30 days was required before biodegradation commenced for xylenes, ethylbenzene, and 1,2,4-trimethylbenzene. An identical test with contaminated aquifer material exhibited not only much longer lag periods but decreased rates of biodegradation; benzene, ethylbenzene, and o-xylene were not significantly degraded within the 6-month time period even though active denitrification occurred at this time. First-order biodegradation rate constants ranged from 0.016 to 0.38/day for uncontaminated core material and from 0.022 to 0.067/day for contaminated core material. Tests with individual compounds in uncontaminated core indicated that benzene and m-xylene inhibited the basal rate of denitrification. These data demonstrate that several aromatic compounds are degraded under denitrifying conditions, but rates of biodegradation may be lower in material contaminated with JP-4 jet fuel.

  10. Biodegradation of aromatic hydrocarbons by aquifer microorganisms under denitrifying conditions

    SciTech Connect

    Hutchins, S.R.; Sewell, G.W.; Smith, G.A. ); Kovacs, D.A. )

    1991-01-01

    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 core material, there was no observable lag period prior to removal of toluene whereas 30 days was required before biodegradation commenced for xylenes, ethylbenzene, and 1,2,4-trimethylbenzene. An identical test with contaminated aquifer material exhibited not only much longer lag periods but decreased rates of biodegradation; benzene, ethylbenzene, and o-xylene were not significantly degraded within the 6-month time period even though active denitrification occurred at this time. First-order biodegradation rate constants ranged from 0.016 to 0.38 day{sup {minus}1} for uncontaminated core material and from 0.022 to 0.067 day{sup {minus}1} for contaminated core material. Tests with individual compounds in uncontaminated core indicated that benzene and m-xylene inhibited the basal rate of denitrification. These data demonstrate that several aromatic compounds can be degraded under denitrifying conditions, but rates of biodegradation may be lower in material contaminated with JP-4 jet fuel.

  11. Thermochemical Properties and Phase Behavior of Halogenated Polycyclic Aromatic Hydrocarbons

    PubMed Central

    Suuberg, Eric M.

    2013-01-01

    Knowledge of vapor pressure of organic pollutants is essential in predicting their fate and transport in the environment. In the present study, the vapor pressures of 12 halogenated polycyclic aromatic compounds (PACs), i.e. 9-chlorofluorene, 2,7-dichlorofluorene, 2-bromofluorene, 9-bromofluorene, 2,7-dibromofluorene, 2-bromoanthracene, 9-chlorophenanthrene, 9-bromophenanthrene, 9,10-dibromophenanthrene, 1-chloropyrene, 7-bromobenz[a]anthracene and 6,12-dibromochrysene, were measured using the Knudsen effusion method over the temperature range of 301 to 464 K. Enthalpies and entropies of sublimation of these compounds were determined via application of the Clausius–Clapeyron equation. The data were also compared with earlier published literature values to study the influence of halogen substitution on vapor pressure of PACs. As expected, the halogen substitution decreases vapor pressure compared to parent compounds, but does not necessarily increase the enthalpy of sublimation. Moreover, the decrease of vapor pressure also depends on the substitution position and the substituted halogen, and the di-substitution of chlorine and/or bromine decreases the vapor pressure compared to single halogen substituted polycyclic aromatic hydrocarbons. Additionally, the enthalpy of fusion and melting temperature of these 12 PACs were determined using differential scanning calorimetry and melting point analysis. PMID:22139714

  12. Chemical Kinetics of Polycyclic Aromatic Hydrocarbons in Comet Impacts

    NASA Astrophysics Data System (ADS)

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

    2004-12-01

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

  13. Autothermal reforming of aliphatic and aromatic hydrocarbon liquids

    NASA Technical Reports Server (NTRS)

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

    1983-01-01

    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.

  14. Effect of bioremediation on polycyclic aromatic hydrocarbon residues in soil

    SciTech Connect

    Wang, Xiaoping; Yu, Xiaobing; Bartha, R. )

    1990-07-01

    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.

  15. Polycyclic aromatic hydrocarbons and cytochrome P450 in HIV pathogenesis

    PubMed Central

    Rao, P. S. S.; Kumar, Santosh

    2015-01-01

    High prevalence of cigarette smoking in HIV patients is associated with increased HIV pathogenesis and disease progression. While the effect of smoking on the occurrence of lung cancer has been studied extensively, the association between smoking and HIV pathogenesis is poorly studied. We have recently shown the possible role of cytochrome P450 (CYP) in smoking/nicotine-mediated viral replication. In this review, we focus on the potential role of CYP pathway in polycyclic aromatic hydrocarbons (PAH), important constituents of cigarette smoke, mediated HIV pathogenesis. More specifically, we will discuss the role of CYP1A1 and CYP1B1, which are the major PAH-activating CYP enzymes. Our results have shown that treatment with cigarette smoke condensate (CSC) increases viral replication in HIV-infected macrophages. CSC contains PAH, which are known to be activated by CYP1A1 and CYP1B1 into procarcinogens/toxic metabolites. The expression of these CYPs is regulated by aryl hydrocarbon receptors (AHR), the cellular target of PAH, and an important player in various diseases including cancer. We propose that PAH/AHR-mediated CYP pathway is a novel target to develop new interventions for HIV positive smokers. PMID:26082767

  16. Reduction of Aromatic Hydrocarbons by Zero-Valent Iron and Palladium Catalyst

    SciTech Connect

    Kim, Young-Hun; Shin, Won Sik; Ko, Seok-Oh; Kim, Myung-Chul

    2004-03-31

    Permeable reactive barrier (PRB) is an alternative technology for soil and groundwater remediation. Zero valent iron, which is the most popular PRB material, is only applicable to halogenated aliphatic organics and some heavy metals. The objective of this study was to investigate reductive dechlorination of halogenated compounds and reduction of non-halogenated aromatic hydrocarbons using zero valent metals (ZVMs) and catalysts as reactive materials for PRBs. A group of small aromatic hydrocarbons such as monochlorophenols, phenol and benzene were readily reduced with palladium catalyst and zero valent iron. Poly-aromatic hydrocarbons (PAHs) were also tested with the catalysts and zero valent metal combinations. The aromatic rings were reduced and partly reduced PAHs were found as the daughter compounds. The current study demonstrates reduction of aromatic compounds by ZVMs and modified catalysts and implicates that PRB is applicable not only for halogenated organic compounds but nonhalogenated aromatic compounds such as PAHs.

  17. ExBox: a polycyclic aromatic hydrocarbon scavenger.

    PubMed

    Barnes, Jonathan C; Juríček, 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

    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 π-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 π-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

  18. Polycyclic aromatic hydrocarbons in the atmospheres of Titan and Jupiter.

    PubMed

    Sagan, C; Khare, B N; Thompson, W R; McDonald, G D; Wing, M R; Bada, J L; Vo-Dinh, T; Arakawa, E T

    1993-09-01

    Polycyclic aromatic hydrocarbons (PAHs) are important components of the interstellar medium and carbonaceous chondrites, but have never been identified in the reducing atmospheres of the outer solar system. Incompletely characterized complex organic solids (tholins) produced by irradiating simulated Titan atmospheres reproduce well the observed UV/visible/IR optical constants of the Titan stratospheric haze. Titan tholin and a tholin generated in a crude simulation of the atmosphere of Jupiter are examined by two-step laser desorption/multiphoton ionization mass spectrometry. A range of two- to four-ring PAHs, some with one to four alkylation sites are identified, with net abundance approximately 10(-4) g g-1 (grams per gram) of tholins produced. Synchronous fluorescence techniques confirm this detection. Titan tholins have proportionately more one- and two-ring PAHs than do Jupiter tholins, which in turn have more four-ring and larger PAHs. The four-ringed PAH chrysene, prominent in some discussions of interstellar grains, is found in Jupiter tholins. Solid state 13C NMR spectroscopy suggests approximately equal to 25% of the total C in both tholins is tied up in aromatic and/or aliphatic alkenes. IR spectra indicate an upper limit in both tholins of approximately equal to 6% by mass in benzenes, heterocyclics, and PAHs with more than four rings. Condensed PAHs may contribute at most approximately 10% to the observed detached limb haze layers on Titan. As with interstellar PAHs, the synthesis route of planetary PAHs is likely to be via acetylene addition reactions. PMID:11539501

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

    NASA Astrophysics Data System (ADS)

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

    The exhaust emission of the polycyclic aromatic hydrocarbons (PAHs) considered toxic to human health were investigated on two spark ignition light duty vehicles, one being gasohol (Gasohol, in Brazil, is the generic denomination for mixtures of pure gasoline plus 20-25% of anhydrous ethyl alcohol fuel (AEAF).)-fuelled and the other a flexible-fuel vehicle fuelled with hydrated ethanol. The influence of fuel type and quality, aged lubricant oil type and use of fuel additives on the formation of these compounds was tested using standardized tests identical to US FTP-75 cycle. PAH sampling and chemical analysis followed the basic recommendations of method TO-13 (United States. Environmental Protection Agency, 1999. Compendium Method TO-13A - Determination of polycyclic Aromatic hydrocarbons (PAH) in Ambient Air Using Gas Chromatography/Mass Spectrometry (CG/MS). Center for environmental research information, Cincinnati, p. 78), with the necessary modification for this particular application. Results showed that the total PAH emission factor varied from 41.9 μg km -1 to 612 μg km -1 in the gasohol vehicle, and from 11.7 μg km -1 to 27.4 μg km -1 in the ethanol-fuelled vehicle, a significant difference in favor of the ethanol vehicle. Generally, emission of light molecular weight PAHs was predominant, while high molecular weights PAHs were not detected. In terms of benzo( a)pyrene toxicity equivalence, emission factors varied from 0.00984 μg TEQ km -1 to 4.61 μg TEQ km -1 for the gasohol vehicle and from 0.0117 μg TEQ km -1 to 0.0218 μg TEQ km -1 in the ethanol vehicle. For the gasohol vehicle, results showed that the use of fuel additive causes a significant increase in the emission of naphthalene and phenanthrene at a confidence level of 90% or higher; the use of rubber solvent on gasohol showed a reduction in the emission of naphthalene and phenanthrene at the same confidence level; the use of synthetic oil instead of mineral oil also contributed significantly to a decrease in the emission of naphthalene and fluorene. In relation to the ethanol vehicle, the same factors were tested and showed no statistically significant influence on PAH emission.

  20. Polycyclic Aromatic Hydrocarbons: From Metabolism to Lung Cancer

    PubMed Central

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

    2015-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

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

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

    EPA Science Inventory

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

  3. 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 ...

  4. 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...

  5. 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 ...

  6. 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...

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

    EPA Science Inventory

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

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

  8. QSARS FOR PREDICTING REDUCTIVE TRANSFORMATION RATE CONSTANTS OF HALOGENATED AROMATIC HYDROCARBONS IN ANOXIC SEDIMENT SYSTEMS

    EPA Science Inventory

    Quantitative structure-activity relationships (QSARs) are developed relating initial and final pseudo-first-order disappearance rate constants of 45 halogenated aromatic hydrocarbons in anoxic sediments to four readily available molecular descriptors: the carbon-halogen bond stre...

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

    EPA Science Inventory

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

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

    EPA Science Inventory

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

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

    SciTech Connect

    Yang, Shiyong; Stock, L.M.

    1996-05-01

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

  12. 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 ...

  13. 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...

  14. Assessment of vascular function in Mexican women exposed to polycyclic aromatic hydrocarbons from wood smoke.

    PubMed

    Ruiz-Vera, Tania; Pruneda-Álvarez, Lucia G; Ochoa-Martínez, Ángeles C; Ramírez-GarcíaLuna, José L; Pierdant-Pérez, Mauricio; Gordillo-Moscoso, Antonio A; Pérez-Vázquez, Francisco J; Pérez-Maldonado, Iván N

    2015-09-01

    The use of solid fuels for cooking and heating is likely to be the largest source of indoor air pollution on a global scale; these fuels emit substantial amounts of toxic pollutants such as polycyclic aromatic hydrocarbons (PAHs) when used in simple cooking stoves (such as open "three-stone" fires). Moreover, indoor air pollution from biomass fuels is considered an important risk factor for human health. The aim of this study was to evaluate the relationship between exposure to PAHs from wood smoke and vascular dysfunction; in a group of Mexican women that use biomass combustion as their main energy source inside their homes. We used 1-hydroxypyrene (1-OHP) as an exposure biomarker to PAHs and it was assessed using high performance liquid chromatography. The endothelium-dependent vasodilation was assessed through a vascular reactivity compression test performed with a pneumatic cuff under visualization of the brachial artery using high resolution ultrasonography (HRU). Assessment of the carotid intima-media thickness (CIMT) was used as an atherosclerosis biomarker (also assessed using HRU); and clinical parameters such as anthropometry, blood pressure, glucose, triglycerides, total cholesterol, HDL cholesterol, LDL cholesterol, among others were also evaluated. The mean concentration of urinary 1-OHP found in exposed women was 0.46±0.32μmol/mol Cr (range: 0.086-1.23μmol/mol Cr). Moreover, vascular dysfunction (diminished endothelium dependent vasodilation) was found in 45% of the women participating in the study. Association between vascular function and 1-OHP levels was found to be significant through a logistic regression analysis (p=0.034; r(2)=0.1329). Furthermore, no association between CIMT and clinical parameters, urinary 1-OHP levels or vascular dysfunction was found. Therefore, with the information obtained in this study, we advocate for the need to implement programs to reduce the risk of exposure to PAHs in communities that use biomass fuels as a main energy source. PMID:26276550

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

    SciTech Connect

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

    1994-06-01

    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.

  16. Polycyclic aromatic hydrocarbons: Primitive pigment systems in the prebiotic environment

    NASA Astrophysics Data System (ADS)

    Deamer, D. W.

    Polycyclic aromatic hydrocarbons (PAH) in the form of polymerized derivatives represent over 90% of the organic material of carbonaceous chondrites. It now appears likely that there was substantial survival of the organic content of meteoritic and cometary infall during late accretion, so that PAH would presumably be major components of the organic inventory present on the prebiotic Earth. An important question relative to chemical evolution and energy transduction is the nature of pigments which could be available to make light energy available to the earliest cellular forms of life. PAH and their derivatives all absorb light in the near UV and blue wavelengths, and are candidates for primitive pigments. We have explored this possibility in a model system consisting of mixtures of pyrene, fluoranthene and pyrene derivatives with hexadecane, dispersed in dilute salt solutions. Upon illumination, photochemical oxidation of the hexadecane occurs, with long-chain amphiphiles such as 2-hexadecanone and 2-hexadecanol as products. Because the reaction proceeds under strictly anaerobic conditions, the source of oxygen is apparently water. We also observed acid pH shifts during illumination. Photochemical production of hydrogen ion is significant, in that chemiosmotic proton gradients across membranes are used by all contemporary cells as a source of energy for ATP synthesis and nutrient transport. To test whether the protons could be used to transduce light energy into a useful form, PAH derivatives were included in lipid bilayer membranes (liposomes). Upon illumination, protons (or acidic products) were produced and accumulated inside the vesicles, so that substantial pH gradients were established across the membranes, acid inside. We conclude that PAH dissolved in aliphatic hydrocarbons absorb light energy and use it to oxidize the hydrocarbon to long-chain amphiphilic molecules. The oxidation is accompanied by release of protons. If PAH derivatives are included in the bilayer membrane of lipid vesicles, protons accumulate within the membrane-bounded volumes to form proton gradients. This system provides a useful model of a primitive photochemical reaction in which light energy is transduced into potentially useable forms.

  17. Localization of deposited polycyclic aromatic hydrocarbons in leaves of Plantago.

    PubMed

    Bakker, M I; Koerselman, J W; Tolls, J; Kollöffel, C

    2001-05-01

    After deposition to foliage, polycyclic aromatic hydrocarbons (PAHs) may remain on the leaf surface, accumulate in the cuticular wax, or diffuse into the remaining interior of the plant. In a field study, the location of deposited PAHs in the leaves of two Plantago species was determined. To this aim, leaves of Plantago major and Plantago media were divided into three fractions. First, the leaves were washed (wash-off fraction), then cuticular wax was extracted (wax fraction). Finally, the remaining leaf material was extracted (interior fraction). The presence of PAHs could be demonstrated in all three fractions. For both plants, the distribution of PAHs over the three fractions changed with molecular weight (mol wt) of the PAHs. The wash-off fraction increased with increasing molecular weight, likely because high molecular-weight PAHs occur predominantly bound to particles, which can be readily washed off from the leaves. In contrast, the amount of PAHs detected in the interior of the leaves decreased with increasing molecular weight. This can be explained by a slow desorption of the PAHs from the particles and a low diffusion rate of the larger molecules. This study shows that washing reduces the amount of high molecular-weight PAHs on plant surfaces. Therefore, washing of leafy vegetables is important to minimize human dietary intake of PAHs. PMID:11337876

  18. Aromatized arborane/fernane hydrocarbons as biomarkers for cordaites

    NASA Astrophysics Data System (ADS)

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

    2006-12-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2016-02-01

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

  20. Polycyclic aromatic hydrocarbon biodegradation by a mixed bacterial culture

    SciTech Connect

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

    1995-12-31

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

  1. Role of iron catalyst on hydroconversion of aromatic hydrocarbons

    SciTech Connect

    Ogata, E.; Horie, Kazuyuki; Wei, Xain-Yong

    1995-12-31

    A symposium on iron-based catalysts for coal liquefaction was held at the 205th ACS National Meeting, and some of the papers have been published in Energy & Fuels. Reviews of the development of catalysts for coal liquefaction were also published in Journal of the Japan institute of Energy, and Ozaki reviewed the results of the studies of upgrading residual oils by means of thermal cracking and coking under reduced pressures, catalytic cracking over nickel ores and iron oxides, and hydrodesulfurization, as well as hydrodemetallization. We reported that catalysis of metallic iron and iron-sulfide catalysts were affected by the S/Fe ratio; the activity increased with pyrrhotite formation and the activity was accelerated by the presence of excess sulfur. Activity of pyrite FeS{sub 2} for phenanthrene hydrogenation and activity of natural ground pyrites for cow liquefaction decreased with storage under air. On the other hand, the NEDOL process for a coal liquefaction pilot plant of 150 t/d which is one of the national projects in Japan, will use pyrites as one of the catalysts for the first-stage because FeS{sub 2} has high activity and is low in price. In this paper, we describe in detail the role of iron catalysts in hydroconversion of aromatic hydrocarbons.

  2. Investigation of polycyclic aromatic hydrocarbons from coal gasification.

    PubMed

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

    2005-01-01

    The hazardous organic pollutants generated from coal gasification, such as polycyclic aromatic hydrocarbons(PAHs), are highly mutagenic and carcinogenic. More researchers have paid particular attention to them. Using air and steam as gasification medium, the experiments of three kinds of coals were carried out in a bench-scale atmospheric fluidized bed gasifier. The contents of the 16 PAHs specified by US EPA in raw coal, slag, bag house coke, cyclone coke and gas were measured by HPLC to study the contents of PAHs in raw coal and the effects of the inherent characters of coals on the formation and release of PAHs in coal gasification. The experimental results showed that the distributions of PAHs in the gasified products are similar to raw coals and the total-PAHs content in coal gasification is higher than in raw coal(except Coal C). The total-PAHs contents increase and then decrease with the rise of fixed carbon and sulfur of coal while there has an opposite variation when volatile matters content increase. The quantities of PAHs reduce with the increase of ash content or the drop of heating value during coal gasification. PMID:15900777

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

    PubMed

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

    2014-12-01

    Thermal decompositions of polycyclic aromatic hydrocarbon (PAH) oxyradicals on various surface sites including five-membered ring, free-edge, zigzag, and armchair have been systematically investigated by using ab initio density functional theory B3LYP/6-311+G(d,p) basis set. The calculation based on Hckel theory indicates that PAHs (3H-cydopenta[a]anthracene oxyradical) with oxyradicals on a five-membered ring site have high chemical reactivity. The rate coefficients of PAH oxyradical decomposition were evaluated by using Rice-Ramsperger-Kassel-Marcus theory and solving the master equations in the temperature range of 1500-2500 K and the pressure range of 0.1-10 atm. The kinetic calculations revealed that the rate coefficients of PAH oxyradical decomposition are temperature-, pressure-, and surface site-dependent, and the oxyradical on a five-membered ring is easier to decompose than that on a six-membered ring. Four-membered rings were found in decomposition of the five-membered ring, and a new reaction channel of PAH evolution involving four-membered rings is recommended. PMID:25386793

  4. Photoinduced toxicity of sediment-bound polycyclic aromatic hydrocarbons

    SciTech Connect

    Greenberg, B.M.; Duxbury, C.L.; Marwood, C.A.; Huang, X.D.; Dixon, D.G.

    1994-12-31

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

  5. Bioavailability of polycyclic aromatic hydrocarbons in the North Sea

    SciTech Connect

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

    1999-06-15

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

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

    SciTech Connect

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

    1994-12-31

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

  7. Aromatic hydrocarbons emissions in diesel and biodiesel exhaust

    NASA Astrophysics Data System (ADS)

    Corrêa, Sérgio Machado; Arbilla, Graciela

    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.

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

    PubMed

    Burmistrz, Piotr; Burmistrz, Michał

    2013-01-01

    The subject of examinations presented in this paper is the distribution of polycyclic aromatic hydrocarbons (PAHs) between solid and liquid phases in samples of raw wastewater and wastewater after treatment. The content of 16 PAHs according to the US EPA was determined in the samples of coke plant wastewater from the Zdzieszowice Coke Plant, Poland. The samples contained raw wastewater, wastewater after physico-chemical treatment as well as after biological treatment. The ΣPHA16 content varied between 255.050 μg L(-1) and 311.907 μg L(-1) in raw wastewater and between 0.940 and 4.465 μg L(-1) in wastewater after full treatment. Investigation of the distribution of PAHs showed that 71-84% of these compounds is adsorbed on the surface of suspended solids and 16-29% is dissolved in water. Distribution of individual PAHs and ΣPHA16 between solid phase and liquid phase was described with the use of statistically significant, linear equations. The calculated values of the partitioning coefficient Kp changed from 0.99 to 7.90 for naphthalene in samples containing mineral-organic suspension and acenaphthylene in samples with biological activated sludge, respectively. PMID:24334890

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

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

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

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

    PubMed

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

    2016-06-01

    The relationship between polycyclic aromatic hydrocarbons (PAHs) and hypertension remains a subject of debate. The aims of this study were to determine an association of concentrations of PAHs in housewives' hair with hypertension risk and the modification effect of single nucleotide polymorphisms (SNPs) related to Phase I metabolism of PAHs. We recruited 405 women for a cross-sectional study in Shanxi Province, China, including 170 with hypertension (the case group) and 235 without hypertension (the control group). We analyzed 26 individual PAHs in hair samples and the SNPs of the genes including cytochrome P450, family 1, subfamily A, polypeptide 1 (CYP1A1), CYP1A2, CYP1B1 and CYP2E1. Our results showed that seven PAHs in hair samples were measured with detection rate >70%. Only acenaphthylene was found to be associated with an increased risk of hypertension with adjustment for the potential confounders following Bonferroni correction, whereas others not. No SNPs of the concerned genes were found to be associated with the risk of hypertension. A multiple interaction effect of PAHs in housewives' hair and SNPs on hypertension risk was not observed. It was concluded that PAHs tended to contribute to the formation of hypertension. PMID:27023119

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

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

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

  12. Accumulation and cycling of polycyclic aromatic hydrocarbons in zooplankton.

    PubMed

    Berrojalbiz, Naiara; Lacorte, Silvia; Calbet, Albert; Saiz, Enric; Barata, Carlos; Dachs, Jordi

    2009-04-01

    Planktonic food webs play an important role driving the environmental fate of persistent organic pollutants, and POP accumulation in phytoplankton has been previously studied for its importance as a first step in the aquatic food webs. However, little is known about the accumulation and cycling of organic pollutants between zooplankton and water. The present study shows the results of laboratory experiments on the bioconcentration (by passive uptake) of polycyclic aromatic hydrocarbons in phytoplankton (Rhodomonas salina) and accumulation in copepods (Paracartia(acartia) granm), by ingestion and diffusion. Both bioconcentration (BCF) and bioaccumulation (BAF) factors show significant correlation with the octanol-water partition coefficient (Kow) for phytoplankton and zooplankton. The BCF values for phytoplankton were 2 orders of magnitude higher than those for copepods. The analysis of fecal pellets shows that elimination by defecation is mainly significant for PAHs taken up from ingested phytoplankton but not due to passive uptake. However, the dominant elimination mechanisms are by far metabolism and diffusive depuration. Indeed, the mass balance suggests that metabolism of PAHs by copepods is a significant process that could play a role in the fate of PAHs in the water column. Uptake, depuration, eggestion, and ingestion rates increased with hydrophobicity of the chemical, while the metabolism rate was slightly higher for the less hydrophobic compounds. Passive partitioning dominated the accumulation of POPs in zooplankton. The derivation of all the uptake and loss rate constants for PAHs opens the doorto future modeling studies of the role of zooplankton in PAH cycling in the marine environment. PMID:19452877

  13. Polycyclic Aromatic Hydrocarbon Ionization Energy Lowering in Water Ices

    NASA Technical Reports Server (NTRS)

    Gudipati, Murthy S.; Allamandola, Louis J.

    2004-01-01

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

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

    PubMed

    Sannino, Anna

    2016-06-01

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

  15. Atmospheric concentrations of polycyclic aromatic hydrocarbons during chimney sweeping.

    PubMed Central

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

    1989-01-01

    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. PMID:2765421

  16. Biodegradation of polycyclic aromatic hydrocarbons in rhizosphere soil

    SciTech Connect

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

    1995-12-31

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

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

    PubMed

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

    2012-01-01

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

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

    PubMed Central

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

    2013-01-01

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

  19. Polycyclic aromatic hydrocarbons in frying oils and snacks.

    PubMed

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

    2006-01-01

    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

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

    PubMed

    Maurya, Anju; Rastogi, Shantanu

    2015-12-01

    The mid infrared emission features observed in various astrophysical sources are attributed to polycyclic aromatic hydrocarbon (PAH) molecules. The models of emission spectra from a collection of PAHs show uncertainty in matching the 6.2 μm feature. This indicates the need to consider a larger variety of PAHs and PAH derivatives. Chemical pathways towards formation of PAHs in the astrophysical environments involve vinyl substituted PAHs as intermediate products. Vibrational spectroscopic study of vinyl-PAHs is reported in the present work. The vinyl group is substituted at similar positions in eight different PAHs. The obtained optimized structures show that vinyl substitution at 2 position in acenes gives planar geometry, while all other vinyl-PAHs are non-planar. Infrared spectra is simulated for neutrals as well as for cations. The results are compared with the spectra of corresponding plain PAHs and analyzed for possible match with astrophysical observations. New features, due to vinyl group in the composite spectra, identified at 6.64, 6.92, 7.27, 8.77 and 10.35 μm fall close to some sub features of the observed emission spectra. The paper provides data that may be used in the emission models particularly along proto planetary nebulae type cool objects. PMID:26117194

  1. Coarse-graining the structure of polycyclic aromatic hydrocarbons clusters.

    PubMed

    Hernández-Rojas, J; Calvo, F; Wales, D J

    2016-05-18

    Clusters of polycyclic aromatic hydrocarbons (PAHs) are essential components of soot and may concentrate a significant fraction of carbon matter in the interstellar medium. In this contribution, coarse-grained potentials are parameterized using all-atom reference data to model PAH molecules, such as coronene (C24H12) or circumcoronene (C54H18), and their aggregates. Low-energy structures of pure coronene or circumcoronene clusters obtained using basin-hopping global optimization are found to agree with atomistic results, and consist of finite 1D columnar motifs, sometimes juxtaposed in larger clusters. The structures are only weakly perturbed when quadrupolar interactions are included. π-Stacking also dominates in binary coronene/circumcoronene aggregates, although intriguing motifs are predicted in which one or more molecules are sandwiched between the other PAH species. The coarse-grained model is also extended to account for interaction with a flat graphitic substrate. In this case, binding is stronger with the substrate than with other molecules, and the PAHs are predicted to arrange into a flat triangular monolayer. PMID:27055581

  2. Polynuclear Aromatic Hydrocarbons Concentrations in Char-Broiled Meat Suya

    NASA Astrophysics Data System (ADS)

    Duke, Okoro; Albert, Ikolo O.

    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 μg kg-1), EF2 (113.83< ±7.93 μg kg-1), WR3 (115.14< ±7.77 μg kg-1), WR4 (81.95< ±6.76 μg kg-1). Benzo(a)pyrene, which is often used as a reference indicator for PNAs carcinogenicity, was determined at levels above 5 μg 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.

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

    NASA Technical Reports Server (NTRS)

    Becker, L.; Bunch, T. E.

    1997-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

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

  6. Some carcinogenic polycyclic aromatic hydrocarbons by photoacoustic spectroscopy

    NASA Astrophysics Data System (ADS)

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

    1999-12-01

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

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

    PubMed

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

    2010-12-01

    Coal-tar based sealcoat has been identified as a source of polycyclic aromatic hydrocarbons (PAHs) in the environment. This study measured the long-term release of PAHs in parking lot runoff and found that the presence of coal tar sealant increased the mass of PAHs released in runoff by over an order of magnitude. PAH concentrations in stormwater from two coal tar sealed parking lots and one unsealed parking lot (control) were monitored over a two-year period. The measured flow volume and concentrations were used to calculate a mass of 9.8-10.8 kg total Σ16 PAHs per hectare exported in stormwater runoff from the two sealed parking lots and 0.34 kg total Σ16 PAHs per hectare from the unsealed control. The study also measured sediment PAH concentration changes in a receiving drainage and found that even partial coverage of a drainage area by coal tar sealant resulted in measurable increases in PAH sediment concentrations; PAH concentrations in sediment in a stormwater swale receiving runoff from both sealed and unsealed lots increased near the outfall from less than 4 mg/kg prior to sealing to 95.7 mg/kg after sealing. Compound ratio plots and principal components analysis were examined and were able to clearly differentiate between pre- and postsealant samples. PMID:21047119

  8. FT-IR spectroscopic studies of polycyclic aromatic hydrocarbons

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

    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.

  9. Occupational exposure to Polycyclic Aromatic Hydrocarbons in wood dust

    NASA Astrophysics Data System (ADS)

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

    2009-02-01

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

  10. Chemical Kinetics of Polycyclic Aromatic Hydrocarbons in Protoplanetary Disks

    NASA Astrophysics Data System (ADS)

    Kress, Monika; Tran, T.; Chiar, J.; Tielens, A. G. G. M.

    2012-05-01

    Polycyclic aromatic hydrocarbons (PAHs) comprise about 10% of the carbon in the interstellar medium. There is evidence of modification of PAHs in protoplanetary disks. What happens to these molecules as they are incorporated into protoplanetary disks? We address this question by investigating the chemical kinetics of PAHs in the disk environment. Kress et al. (2010) investigated the chemical behavior of PAHs at temperatures from 1000 to 2000 K at a pressure of 1e-6 bar, and proposed the concept of the 'soot line', analogous to the 'snow line' in the solar nebula. Inside of the soot line, PAHs are irreversibly destroyed via thermally-driven reactions. We will extend this study to more realistic disk conditions and timescales. In a related project (see poster by Tran, Chiar, et al.), we are investigating the differences in the PAH physical characteristics in quiescent dense clouds versus the environment around embedded protostars. Together, these studies will help us understand (1) the fate of interstellar PAHs in planet-forming disks and (2) the relationship between interstellar and solar system PAHs. We also will investigate the soot line in disks around sub-solar mass stars (e.g. M dwarfs). This work has been supported by the NASA Astrobiology Institute's Virtual Planetary Laboratory (PI: V. Meadows) and the NASA/EPOESS program (PI: C. Phillips).

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

    PubMed Central

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

    2014-01-01

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

  12. Pollutants in Hong Kong soils: polycyclic aromatic hydrocarbons.

    PubMed

    Chung, M K; Hu, R; Cheung, K C; Wong, M H

    2007-03-01

    An extensive soil survey was carried out to study the polycyclic aromatic hydrocarbon (PAH) contaminations in 138 soil samples collected throughout Hong Kong. Results demonstrated that there were low levels of PAH contaminations (median of summation operator 16US EPA PAHs=140 microg kg(-1)) for all land uses (urban park, greening area, country park, rural area, restored landfill, agricultural farmland, orchard farm, crematorium, industrial and near highway area). However, localized hotspots were identified with summation operator 16PAH concentrations as high as 19,500 microg kg(-1) in one urban park. These findings were also confirmed by multivariate analysis. Comparison of PAH profiles showed a widespread domination of its 4-ring member. The major contribution was vehicular emissions from petroleum, and however at the hotspots, the improper disposal of used motor oils. In general, the pollution levels for all the land uses were below the recommended values for residential and general purposes stated in soil quality guidelines such as Netherlands and Denmark except certain identified hotspots. The potential health hazards imposed by these hotspots were alarming, and their existence (3 out of 138 samples) suggested that sole monitoring of atmospheric PAHs may not adequately address the hidden risks to human in urban city. PMID:17109918

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

    PubMed

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

    2016-04-01

    Polycyclic aromatic hydrocarbons (PAHs) are organic micro pollutants which are persistent compounds in the environment due to their hydrophobic nature. Concerns over their adverse effects in human health and environment have resulted in extensive studies on various types of PAHs removal methods. Sorption is one of the widely used methods as PAHs possess a great sorptive ability into the solid media and their low aqueous solubility property. Several adsorbent media such as activated carbon, biochar, modified clay minerals have been largely used to remove PAHs from aqueous solution and to immobilise PAHs in the contaminated soils. According to the past studies, very high removal efficiency could be achieved using the adsorbents such as removal efficiency of activated carbon, biochar and modified clay mineral were 100%, 98.6% and >99%, respectively. PAHs removal efficiency or adsorption/absorption capacity largely depends on several parameters such as particle size of the adsorbent, pH, temperature, solubility, salinity including the production process of adsorbents. Although many studies have been carried out to remove PAHs using the sorption process, the findings have not been consolidated which potentially hinder to get the correct information for future study and to design the sorption method to remove PAHs. Therefore, this paper summarized the adsorbent media which have been used to remove PAHs especially from aqueous solutions including the factor affecting the sorption process reported in 142 literature published between 1934 and 2015. PMID:26820781

  14. Polycyclic aromatic hydrocarbons and fatal ischemic heart disease

    SciTech Connect

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

    2005-11-01

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

  15. Fibrous adsorbent for removal of aqueous aromatic hydrocarbons.

    PubMed

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

    2007-01-01

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

  16. Oxidation of polynuclear aromatic hydrocarbons in water. 1: Ozonation

    SciTech Connect

    Beltran, F.J.; Encinar, J.M.; Rivas, J.; Ovejero, G.

    1995-05-01

    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.

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

    SciTech Connect

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

    2013-09-10

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

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

    PubMed

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

    2007-12-15

    The atmospheric outflow of polycyclic aromatic hydrocarbons (PAHs) from Guangdong, China, a region of high PAH emission, was modeled using a potential receptor influence function (PRIF) probabilistic model which was based on a spatially resolved PAH inventory and air mass forward-trajectory calculations. Photochemical degradation and deposition (dry and wet) of PAHs during atmospheric transport were taken into consideration. On average, 48% of the PAHs (by mass) remained in the atmosphere for a transport period of 5 days, staying within the boundary of the source region. The medium molecular weight PAHs (four rings) were predicted to travel longer distances in the atmosphere than the low (three rings) or high molecular weight PAHs (five rings) because they are less photodegradable than the lower molecular weight, gas-phase PAHs and less likelyto undergo wet and dry depositions than the higher molecular weight, particulate phase PAHs. Under the strong influence of the East Asian monsoons in winter, the predominant outflow pattern of PAHs from Guangdong was to the South China Sea and Southeast Asian countries. In summer, PAHs were transported primarily to northern mainland China. Under particular weather conditions in winter, the PAH-containing air masses were lifted by cold fronts or convection and transported toward the Pacific Ocean by westerly winds. In addition to the distinct seasonality in PAH dispersion and outflow, interannual long-term variation in the outflow is likely influenced by El Nio and southern oscillation. PMID:18200865

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

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

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

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

    SciTech Connect

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

    2005-10-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-06-01

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

  2. Polycyclic aromatic hydrocarbon emissions from joss paper furnaces

    NASA Astrophysics Data System (ADS)

    Yang, Hsi-Hsien; Jung, Ray-Chen; Wang, Ya-Fen; Hsieh, Lien-Te

    The emissions of polycyclic aromatic hydrocarbons (PAHs) were quantified for two joss paper furnaces burning two kinds of joss papers (recycled paper made and virgin bamboo made). A cyclone and a wet scrubber were installed in series on one of the two furnaces. Particulate and gaseous PAHs were collected with a sampling system meeting the criteria of U.S. EPA Modified Method 5. Twenty-one species of PAH were analyzed by GC/MS. Individual PAH emission factors vary from less than 1 mg kg -1 fuel to several tens of mg kg -1 fuel. The total (sum of 21 compounds) and the carcinogenic PAH (benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, indeno[1,2,3,-cd]pyrene, dibenz[a,h]anthracene) emission factors were not statistically different for the two furnaces and averaged 71.0 and 3.2 mg kg -1, respectively. The PAH profiles showed a predominance of naphthalene (58.1%), phenanthrene (11.7%) and fluorene (7.5%). Of the two joss papers examined, bamboo-made joss paper showed less emission in both particulate and gaseous PAHs. For particulate and gaseous PAHs, the removal efficiencies of total PAHs by the air pollution control devices were 42.5% and 11.7%, respectively. PAH emission factors in high airflow conditions were generally lower than those in low airflow condition.

  3. Absorption Spectroscopy of Polycyclic Aromatic Hydrocarbons under Interstellar Conditions

    NASA Technical Reports Server (NTRS)

    Stone, Bradley M.

    1996-01-01

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

  4. Polycyclic aromatic hydrocarbon ions and the diffuse interstellar bands

    NASA Technical Reports Server (NTRS)

    Salama, F.; Allamandola, L. J.

    1995-01-01

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

  5. Photochlorination of Polycyclic Aromatic Hydrocarbons in Acidic Brine Solution.

    PubMed

    Ohura, Takeshi; Miwa, Makoto

    2016-04-01

    The potential for the formation of chlorinated polycyclic aromatic hydrocarbons via photochlorination of PAHs has been investigated in milli-Q water/synthetic water containing NaCl and PAHs with either UV or visible light. The photochlorination of pyrene occurred under acidic conditions in the presence of both UV and visible light, resulting in 1-chloropyrene as the main product. Benzo[a]pyrene yielded 6-chlorobenzo[a]pyrene following visible light irradiation; however the reaction was dependent upon solution pH. The photochlorination of PAHs was proposed to proceed via a consecutive reaction model. The rate constants associated with the photochlorination and photodecay processes were determined with the observed and theoretical values displaying similar trends, whereas the observed values were approximately 50-1000 times lower than the theoretical values. The lower observed values could be due to undergo photodecay rather than photochlorination of PAHs. Therefore, as photochlorination of PAHs appears to be significantly affected by solution pH, this information may allow for minimizing the impact on the environment. PMID:26728279

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

    PubMed

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

    2008-07-15

    A potential receptor influence function (PRIF) model, based on air mass forward trajectory calculations, was applied to simulate the atmospheric transport and outflow of polycyclic aromatic hydrocarbons (PAHs) emitted from China. With a 10 day atmospheric transport time, most neighboring countries and regions, as well as remote regions, were influenced by PAH emissions from China. Of the total annual PAH emission of 114 Gg, 92.7% remained within the boundary of mainland China. The geographic distribution of PRIFs within China was similar to the geographic distribution of the source regions, with high values in the North China Plain, Sichuan Basin, Shanxi, and Guizhou province. The Tarim basin and Sichuan basin had unfavorable meteorological conditions for PAH outflow. Of the PAH outflow from China (8092 tons or 7.1% of the total annual PAH emission), approximately 69.9% (5655 tons) reached no further than the offshore environment of mainland China and the South China Sea. Approximate 227, 71, 746, and 131 tons PAHs reached North Korea, South Korea, Russia-Mongolia region, and Japan, respectively, 2-4 days after the emission. Only 1.4 tons PAHs reached North America after more than 9 days. Interannual variation in the eastward PAH outflow was positively correlated to cold episodes of El Niño/Southern Oscillation. However, trans-Pacific atmospheric transport of PAHs from China was correlated to Pacific North America index (PNA) which is associated with the strength and position of westerly winds. PMID:18754369

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

    SciTech Connect

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

    2008-07-15

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

  8. Bacterial oxidation of the polycyclic aromatic hydrocarbons acenaphthene and acenaphthylene.

    PubMed Central

    Schocken, M J; Gibson, D T

    1984-01-01

    A Beijerinckia sp. and a mutant strain, Beijerinckia sp. strain B8/36, were shown to cooxidize the polycyclic aromatic hydrocarbons acenaphthene and acenaphthylene. Both organisms oxidized acenaphthene to the same spectrum of metabolites, which included 1-acenaphthenol, 1-acenaphthenone, 1,2-acenaphthenediol, acenaphthenequinone, and a compound that was tentatively identified as 1,2-dihydroxyacenaphthylene. In contrast, acenaphthylene was oxidized to acenaphthenequinone and the compound tentatively identified as 1,2-dihydroxyacenaphthylene by the wild-type strain of Beijerinckia. Both of these products were also formed when the organism was incubated with synthetic cis-1,2-acenaphthenediol. A metabolite identified as cis-1,2-acenaphthenediol was formed from acenaphthylene by the mutant Beijerinckia sp. strain B8/36. Cell extracts prepared from the wild-type Beijerinckia strain contain a constitutive pyridine nucleotide-dependent dehydrogenase which can oxidize 1-acenaphthenol and 9-fluorenol. The results indicate that although acenaphthene and acenaphthylene are both oxidized to acenaphthenequinone, the pathways leading to the formation of this end product are different. PMID:6089663

  9. Separation of {sup 32}P-postlabeled DNA adducts of polycyclic aromatic hydrocarbons and nitrated polycyclic aromatic hydrocarbons by HPLC

    SciTech Connect

    King, L.C.; Gallagher, J.E.; Lewtas, J.; George, M.

    1994-07-01

    The {sup 32}P-postlabeling assay, thin-layer chromatography, and reverse-phase high-pressure liquid chromatography (HPLC) were used to separate DNA adducts formed from 10 polycyclic aromatic hydrocarbons (PAHs) and 6 nitrated polycyclic aromatic hydrocarbons (NO{sub 2}-PAHs). The PAHs included benzo[j]fluoranthene, benzo[k]fluoranthene, indeno[1,2,3-cd]pyrene, benzo[a]pyrene, chrysene, 6-methylchrysene, 5-methylchrysene, and benz[a]anthracene. The NO{sub 2}-PAHs included 1-nitropyrene, 2-nitrofluoranthene, 3-nitrofluoranthene, 1,6-dinitropyrene, 1,3-dinitropyrene, and 1,8-dinitropyrene. Separation of seven of the major PAH-DNA adducts was achieved by an initial PAH HPLC gradient system. The major NO{sub 2}-PAH-DNA adducts were not all separated from each other using the initial PAH HPLC gradient but were clearly separated from the PAH-DNA adducts. A second NO{sub 2}-PAH HPLC gradient system was developed to separate NO{sub 2}-PAH-DNA adducts following one-dimensional TLC and HPLC analysis. HPLC profiles of NO{sub 2}-PAH-DNA adducts were compared using both adduct enhancement versions of the {sup 32}P-postlabeling assay to evaluate the use of this technique on HPLC to screen for the presence of NO{sub 2}-PAH-DNA adducts. To demonstrate the application of these separation methods to a complex mixture of DNA adducts, the chromatographic mobilities of the {sup 32}P-postlabeled DNA adduct standards (PAHs and NO{sub 2}-PAHs) were compared with those produced by a complex mixture of polycyclic organic matter (POM) extracted from diesel emission particles. The diesel-derived adducts did not elute with the identical retention time of any of the PAH or NO{sub 2}-PAH standards used in this study. HPLC analyses of the NO{sub 2}-PAH-derived adducts (butanol extracted) revealed the presence of multiple DNA adducts.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  11. Levels of Polycyclic Aromatic Hydrocarbons in Maternal Serum and Risk of Neural Tube Defects in Offspring

    PubMed Central

    2015-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants, and have been reported to be a risk factor for human neural tube defects (NTDs). We investigated the relationship between PAH concentrations in maternal serum and NTD risk in offspring using a case-control study design, and explored the link between PAH concentrations to household energy usage characteristics and life styles. One hundred and seventeen women who had NTD-affected pregnancies (cases) and 121 women who delivered healthy infants (controls) were recruited in Northern China. Maternal blood samples were collected at pregnancy termination or at delivery. Twenty-seven PAHs were measured by gas chromatography–mass spectrometry. The concentrations of 13 individual PAHs detected were significantly higher in the cases than in the controls. Clear dose–response relationships between concentrations of most individual PAHs and the risk of total NTDs or subtypes were observed, even when potential covariates were adjusted for. High-molecular-weight PAHs (H-PAHs) showed higher risk than low-molecular-weight PAHs (L-PAHs). No associations between PAH concentrations and indoor life styles and energy usage characteristics were observed. It was concluded that maternal exposure to PAHs was associated with an increased risk of NTDs, and H-PAHs overall posed a higher risk for NTDs than L-PAHs. PMID:25488567

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

    PubMed Central

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

    2011-01-01

    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. PMID:21845152

  13. Exposure to polycyclic aromatic hydrocarbons and assessment of potential risks in preschool children.

    PubMed

    Oliveira, Marta; Slezakova, Klara; Delerue-Matos, Cristina; Pereira, Maria do Carmo; Morais, Simone

    2015-09-01

    As children represent one of the most vulnerable groups in society, more information concerning their exposure to health hazardous air pollutants in school environments is necessary. Polycyclic aromatic hydrocarbons (PAHs) have been identified as priority air pollutants due to their mutagenic and carcinogenic properties that strongly affect human health. Thus, this work aims to characterize levels of 18 selected PAHs in preschool environment, and to estimate exposure and assess the respective risks for 3-5-year-old children (in comparison with adults). Gaseous PAHs (mean of 44.5 ± 12.3 ng m(-3)) accounted for 87% of the total concentration (ΣPAHs) with 3-ringed compounds being the most abundant (66% of gaseous ΣPAHs). PAHs with 5 rings were the most abundant ones in the particulate phase (PM; mean of 6.89 ± 2.85 ng m(-3)) being predominantly found in PM1 (78% particulate ΣPAHs). Overall child exposures to PAHs were not significantly different between older children (4-5 years old) and younger ones (3 years old). Total carcinogenic risks due to particulate-bound PAHs indoors were higher than outdoor ones. The estimated cancer risks of both preschool children and the staff were lower than the United States Environmental Protection Agency (USEPA) threshold of 10(-6) but slightly higher than WHO-based guideline. PMID:25943510

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

    DOEpatents

    Baker, Eddie G.; Elliott, Douglas C.

    1993-01-01

    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.

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

    DOEpatents

    Baker, E.G.; Elliott, D.C.

    1993-01-19

    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 compounds 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.

  16. Aryl hydrocarbon receptor expression is associated with a family history of upper gastrointestinal tract cancer in a high-risk population exposed to aromatic hydrocarbons

    SciTech Connect

    Roth, M.J.; Wei, W.Q.; Baer, J.; Abnet, C.C.; Wang, G.Q.; Sternberg, L.R.; Warner, A.C.; Johnson, L.L.; Lu, N.; Giffen, C.A.; Dawsey, S.M.; Qiao, Y.L.; Cherry, J.

    2009-09-15

    Polycyclic aromatic hydrocarbon (PAH) exposure is a risk factor for esophageal squamous cell carcinoma, and PAHs are ligands of the aryl hydrocarbon receptor (AhR). This study measured the expression of AhR and related genes in frozen esophageal cell samples from patients exposed to different levels of indoor air pollution, who did or did not have high-grade squamous dysplasia and who did or did not have a family history of upper gastrointestinal tract (UGI) cancer. 147 samples were evaluated, including 23 (16%) from patients with high-grade dysplasia and 48 (33%) from patients without dysplasia who heated their homes with coal, without a chimney (a 'high' indoor air pollution group), and 27 (18%) from patients with high-grade dysplasia and 49 (33%) from patients without dysplasia who did not heat their homes at all (a 'low' indoor air pollution group). Sixty-four (44%) had a family history of UGI cancer. RNA was extracted and quantitative PCR analysis was done. AhR gene expression was detectable in 85 (58%) of the samples and was >9-fold higher in those with a family history of UGI cancer (median expression (interquartile range), -1,964 (-18,000, -610) versus -18,000 (-18,000, -1036); P = 0.02, Wilcoxon rank-sum test). Heating status, dysplasia category, age, gender, and smoking were not associated with AhR expression (linear regression; all P values {ge} 0.1). AhR expression was higher in patients with a family history of UGI cancer. Such individuals may be more susceptible to the deleterious effects of PAH exposure, including PAH-induced cancer.

  17. Polycyclic aromatic hydrocarbons in the atmosphere of Shanghai, China.

    PubMed

    Chen, Yingjun; Feng, Yanli; Xiong, Shengchun; Liu, Dongyan; Wang, Gang; Sheng, Guoying; Fu, Jiamo

    2011-01-01

    Shanghai is the largest industrial and commercial city in China, and its air quality has been concerned for several years. However, scarce study had been made on the seasonal levels of atmospheric polycyclic aromatic hydrocarbons (PAHs), together with their gas-particle partitioning and potential emission sources. Based on an intensive sampling campaign at urban and suburban areas in Shanghai during four seasons of 2005-2006, this study presented the measurement of PAH concentrations in both particulate and gaseous phases, as well as seasonal and spatial variability. The results showed that the annual PAH levels (gas + particle) were 167 ± 109 ng m⁻³ at the urban site and 216 ± 86.5 ng m⁻³ at the suburban site. Gaseous PAHs (>70%) dominated the total PAH mass at both sites, while particulate PAHs contributed more than 90% of the toxic power according to benzo(a)pyrene-equivalent carcinogenic parameter. Different seasonal trend of PAH concentrations was observed between the two sites, and it may be explained by complicated factors such as sampling heights, local/regional emission sources, and climatic conditions. The gas-particle partitioning of PAHs in all samples was calculated, and strong linear correlations between log K (p) and log P(L)° were observed, with shallower slopes (m(r)) at the suburban site than the urban one and in warm season than the cold months, indicating the different equilibrium conditions of PAHs in spatial and seasonal scales in Shanghai. The slope (m(r) = - 0.96) and correlation coefficient (R² = 0.81) for four-ring PAHs were closest to theoretical equilibrium conditions among compounds with various aromatic rings. Finally, the potential PAH sources were estimated based on principal factor analysis with multiple linear regressions. Ground volatilization dominated the PAH pollutions at both sites, while vehicles and coal consumption were the other main emission sources, which totally contributed 32.0% (suburban) to 49.2% (urban) of PAH mass in Shanghai atmosphere. The effects of wood and biomass burning were also detected, but their contributions to PAHs were negligible. PMID:20145995

  18. 40 CFR Table 2c to Subpart E of... - Reactivity Factors for Aromatic Hydrocarbon Solvent Mixtures

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 6 2013-07-01 2013-07-01 false Reactivity Factors for Aromatic Hydrocarbon Solvent Mixtures 2C Table 2C to Subpart E of Part 59 Protection of Environment ENVIRONMENTAL... Hydrocarbon Solvent Mixtures Bin Boiling range(degrees F) Criteria Reactivityfactor (g O3/g VOC) 21...

  19. 40 CFR Table 2c to Subpart E of... - Reactivity Factors for Aromatic Hydrocarbon Solvent Mixtures

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 6 2014-07-01 2014-07-01 false Reactivity Factors for Aromatic Hydrocarbon Solvent Mixtures 2C Table 2C to Subpart E of Part 59 Protection of Environment ENVIRONMENTAL... Hydrocarbon Solvent Mixtures Bin Boiling range(degrees F) Criteria Reactivityfactor (g O3/g VOC) 21...

  20. 40 CFR Table 2c to Subpart E of... - Reactivity Factors for Aromatic Hydrocarbon Solvent Mixtures

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 6 2012-07-01 2012-07-01 false Reactivity Factors for Aromatic Hydrocarbon Solvent Mixtures 2C Table 2C to Subpart E of Part 59 Protection of Environment ENVIRONMENTAL... Hydrocarbon Solvent Mixtures Bin Boiling range(degrees F) Criteria Reactivityfactor (g O3/g VOC) 21...

  1. UV irradiation of polycyclic aromatic hydrocarbons in ices: production of alcohols, quinones, and ethers

    NASA Technical Reports Server (NTRS)

    Bernstein, M. P.; Sandford, S. A.; Allamandola, L. J.; Gillette, J. S.; Clemett, S. J.; Zare, R. N.

    1999-01-01

    Polycyclic aromatic hydrocarbons (PAHs) in water ice were exposed to ultraviolet (UV) radiation under astrophysical conditions, and the products were analyzed by infrared spectroscopy and mass spectrometry. Peripheral carbon atoms were oxidized, producing aromatic alcohols, ketones, and ethers, and reduced, producing partially hydrogenated aromatic hydrocarbons, molecules that account for the interstellar 3.4-micrometer emission feature. These classes of compounds are all present in carbonaceous meteorites. Hydrogen and deuterium atoms exchange readily between the PAHs and the ice, which may explain the deuterium enrichments found in certain meteoritic molecules. This work has important implications for extraterrestrial organics in biogenesis.

  2. Biotransformation of chlorobenzene and aromatic hydrocarbons under denitrifying conditions. Final report

    SciTech Connect

    Bouwer, E.J.; Trizinsky, M.A.

    1993-12-01

    Aromatic hydrocarbons are common contaminants in surface water and ground water supplies. Objectives of this research were to improve our understanding of the environmental fate of chlorobenzene (CB) and aromatic hydrocarbons under denitrifying conditions and to assess the extent to which nitrate can enhance bioremediation in contaminated soils and ground water. CB and toluene (TOL) biodegradation under denitrifying conditions was measured in a series of aqueous batch experiments in which CB or TOL was the sole aromatic substrate. The positive biotransformations of CB and TOL under denitrification suggest that injection of nitrate into a region of subsurface contamination could result in a successful bioremediation.

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

    SciTech Connect

    Oja, V.; Suuberg, E.M.

    1998-05-01

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

  4. Assessment of population exposure to Polycyclic Aromatic Hydrocarbons (PAHs) using integrated models and evaluation of uncertainties

    NASA Astrophysics Data System (ADS)

    Gariazzo, Claudio; Lamberti, Mafalda; Hänninen, Otto; Silibello, Camillo; Pelliccioni, Armando; Porta, Daniela; Cecinato, Angelo; Gherardi, Monica; Forastiere, Francesco

    2015-01-01

    Polycyclic Aromatic Hydrocarbons (PAHs) are considered among the most dangerous air pollutants due to their carcinogenic and mutagenic characteristics. Populations living in urban area are exposed to these pollutants because of their proximity to the emission sources. However, the spatial and temporal characteristics of PAHs concentrations in such areas are not well known. An integrated modeling approach is here presented to estimate exposure to PAHs content in PM2.5 of children and elderly people living in the city of Rome, Italy. It is based on a microenvironment approach in which exposure is estimated by accounting for PAHs concentrations experienced by the target population in the most visited living environments. The model uses data provided by the EU LIFE + EXPAH project: indoor/outdoor PAHs concentrations collected in homes, schools, cars, buses and offices to derive PAHs infiltration factors for the specific environments; time activity to identify daytime profiles of the target population and information on the prevailing living environments; ambient PAHs concentration fields. The latter have been obtained by integrating Chemical Transport Model (CTM) results with measurements collected by the EXPAH project. Uncertainties in the estimation of PAHs exposure has been evaluated by applying a Monte Carlo statistical approach using probability density function based on observed exposure parameters. Results were calculated for one year (June 2011-May 2012). The downtown area was found to be the most contaminated one with concentrations up to 2 ± 1 and 0.6 ± 0.2 ng/m3, on an annual basis, respectively for ∑4PAHs (e.g. B[a]P, B[b]F, B[k]F and indeno(1,2,3-cd)pyrene) and B[a]P. Results do not exhibit significant differences on ∑4PAHs exposure between children and elderly people, mainly due to the prevalence of indoor microenvironments in the time activity data, and to the little difference in the indoor/outdoor infiltration. Seasonality was identified as an important factor contributing to the overall exposure. The higher PAHs emissions during the heating period determine a greater exposure during winter. Homes have been identified as the microenvironments that most contribute to PAHs exposure followed by schools.

  5. Carcinogenic activity of polycyclic aromatic hydrocarbons bounded on particle fraction.

    PubMed

    Jakovljević, Ivana; Pehnec, Gordana; Vadjić, Vladimira; Šišović, Anica; Davila, Silvije; Bešlić, Ivan

    2015-10-01

    Polycyclic aromatic hydrocarbons (PAHs) originate from a variety of natural and industrial processes. In this paper, concentrations of nine PAHs in PM10 particle fraction were measured concurrently at four different sites (rural, urban residential, urban traffic, and residential-industrial) in continental Croatia. Measurements at all of the four sites showed much higher average concentrations for all of the PAHs in the winter period. The highest winter average values were measured at the industrial site and the lowest at the rural and the urban residential site. In the summer, the highest average values were also measured in the industrial area, except for benzo(ghi)perylene and indeno(1,2,3-cd)pyrene, which showed the highest average values in the rural area. Factor analysis has been applied to PAH concentrations to identify their potential sources. Extracted factors have been interpreted on basis of previous studies and weather conditions. The diagnostic ratios calculated in this study indicated mixed sources at all of the sites. The contribution of gasoline and diesel from traffic was significant at all of the sites except for the urban industrial. In the winter, potential PAH sources also arose from wood combustion. The industrial site differed from the other sites with the highest influence of diesel sources and refinery during the summer months. The contribution of BaP in total carcinogenic activity exceeded 50 % in both seasons at all of the measured sites, which suggests that BaP could be suitable as a marker of the carcinogenic potential of a PAH mixture. PMID:26050151

  6. Engineered antibodies for monitoring of polynuclear aromatic hydrocarbons

    SciTech Connect

    Karu, A.E.; Roberts, V.A.; Li, Q.X.

    1998-06-01

    '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.'

  7. Analysis of polycyclic aromatic hydrocarbons in cooking oil fumes.

    PubMed

    Li, S; Pan, D; Wang, G

    1994-01-01

    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 and fumes from three catering shops. All samples contained benzo(a)pyrene (BaP) and dibenzo (a,h)anthracene (DBahA). In addition, the concentration of DBahA was 5.7 to 22.8 times higher than that of BaP in the fume samples. Concentrations of BaP and DBahA were, respectively, 0.463 and 5.736 micrograms/g in refined vegetable oil, 0.341 and 3.725 micrograms/g in soybean oil, and 0.305 and 4.565 micrograms/g in vegetable oil. Investigation of PAH concentrations at three catering shops showed that the level of BaP at a Youtiao (deep-fried twisted dough sticks) shop was 4.18 micrograms/100 m3, 2.28 micrograms/100 m3 at a Seqenma (candied fritters) workshop, and 0.49 micrograms/100 m3 at a kitchen of a restaurant; concentrations of DBahA were 33.80, 14.41, and 3.03 micrograms/100 m3, respectively. The high concentration of carcinogens, such as BaP and DBahA, in cooking oil fumes might help explain why Chinese women, who spend more time exposed to cooking oil fumes than men, have a high incidence of pulmonary adenocarcinoma. PMID:8161241

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

    PubMed

    Jensen, John; Sverdrup, Line E

    2003-01-01

    With the overall perspective of calculating soil quality criteria (SQC) for the group of polycyclic aromatic hydrocarbons (PAHs), the existing ecotoxicity data for the soil compartment have been reviewed. The majority of data useful in the context of deriving SQC are of recent origin. Soil quality criteria are considered valuable tools for assessing the environmental risk of contamination, as they may give guidance on concentration limits for various chemicals to protect the function and structure of ecosystems. Soil quality criteria for soil-dwelling species were calculated using various assumptions and two internationally accepted methods, i.e., application of assessment factors and species sensitivity distributions, respectively. It was suggested to derive ecotoxicological soil quality criteria, which focus on the lower molecular weight PAHs, i.e., those with log Kow values lower than 5.5 or 6; this is the log Kow range where a cutoff in toxicity for terrestrial species is expected for narcotic substances. Predicted values from the two methods were similar. Calculations showed that, for four individual PAHs of three or four rings, SQC fall in the range of 1.0 and 2.5 mg kg(-1). However, as no individual PAH is fond alone it is suggested to use a sum criterion for a group of PAHs instead. The different possibilities to calculate such a sum criterion are discussed. Based on toxicity data presented here and the average abundance of different PAHs in nearly 1000 Danish soil samples, an ecotoxicological soil quality criterion of 25 mg kg(-1) dry weight for the sum of the eight PAHs acenaphthene, fluorene, anthracene, phenanthrene, pyrene, fluoranthene, benz[a]anthracene, and chrysene is suggested. PMID:15366584

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

    SciTech Connect

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

    1989-01-01

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

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

    SciTech Connect

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

    1993-03-01

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

  11. Ambient polycyclic aromatic hydrocarbons and pulmonary function in children.

    PubMed

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

    2015-05-01

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

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

    PubMed Central

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

    2011-01-01

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

  13. Polycyclic Aromatic Hydrocarbon Emission within Lyα Blobs

    NASA Astrophysics Data System (ADS)

    Colbert, James W.; Scarlata, Claudia; Teplitz, Harry; Francis, Paul; Palunas, Povilas; Williger, Gerard M.; Woodgate, Bruce

    2011-02-01

    We present Spitzer observations of Lyα blobs (LABs) at z = 2.38-3.09. The mid-infrared ratios (4.5 μm/8 μm and 8 μm/24 μm) indicate that ~60% of LAB infrared counterparts are cool, consistent with their infrared output being dominated by star formation and not active galactic nuclei (AGNs). The rest have a substantial hot dust component that one would expect from an AGN or an extreme starburst. Comparing the mid-infrared to submillimeter fluxes (~850 μm or rest-frame far-infrared) also indicates that a large percentage (~2/3) of the LAB counterparts have total bolometric energy output dominated by star formation, although the number of sources with submillimeter detections or meaningful upper limits remains small (~10). We obtained Infrared Spectrograph (IRS) spectra of six infrared-bright sources associated with LABs. Four of these sources have measurable polycyclic aromatic hydrocarbon (PAH) emission features, indicative of significant star formation, while the remaining two show a featureless continuum, indicative of infrared energy output completely dominated by an AGN. Two of the counterparts with PAHs are mixed sources, with PAH line-to-continuum ratios and PAH equivalent widths indicative of large energy contributions from both star formation and AGN. Most of the LAB infrared counterparts have large stellar masses, around 1011 M sun. There is a weak trend of mass upper limit with the Lyα luminosity of the host blob, particularly after the most likely AGN contaminants are removed. The range in likely energy sources for the LABs found in this and previous studies suggests that there is no single source of power that is producing all the known LABs.

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

    SciTech Connect

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

    2007-04-01

    High temperature carbon oxidation in primary aluminum smelters results in the release of polycyclic aromatic hydrocarbons (PAH) into the environment. The main source of PAH are the anodes, which are composed of petroleum coke (black carbon, BC) and coal tar pitch. To elucidate the dominant carbonaceous phase controlling the environmental fate of PAH in aluminum smelter residues (coke BC and/or coal tar), the sorptive behavior of PAHs has been determined, using passive samplers and infinite-sink desorption methods. Samples directly from the wet scrubber were studied as well as ones from an adjacent 20-year old storage lagoon and roof dust from the smelter. Carbon-normalized distribution coefficients of native PAHs were 2 orders of magnitude higher than expected based on amorphous organic carbon (AOC)/water partitioning, which is in the same order of magnitude as reported literature values for soots and charcoals. Sorption isotherms of laboratory-spiked deuterated phenanthrene showed strong (about 100 times stronger than AOC) but nonetheless linear sorption in both fresh and aged aluminum smelter residues. The absence of nonlinear behavior typical for adsorption to BC indicates that PAH sorption in aluminum smelter residues is dominated by absorption into the semi-solid coal tar pitch matrix. Desorption experiments using Tenax showed that fresh smelter residues had a relatively large rapidly desorbing fraction of PAH (35-50%), whereas this fraction was strongly reduced (11-16%) in the lagoon and roof dust material. Weathering of the coal tar residue and/or redistribution of PAH between coal tar and BC phases could explain the reduced availability in aged samples. 38 refs., 5 figs., 1 tab.

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

    PubMed Central

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

    2012-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

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

    PubMed Central

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

    2013-01-01

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

  18. Factors associated with human exposures to polycyclic aromatic hydrocarbons

    SciTech Connect

    Lioy, P.J.; Greenberg, A. )

    1990-03-01

    The number and quantities of PAH emitted and accumulated within various environmental media require the development and application of new methods for determining the major routes of exposure to individual and selected compounds. From research that has been conducted on airborne BaP and other selected PAH it appears that they can accumulate indoors as well as outdoors. Smoking seems to be a major contributor for direct and passive inhalation, but the role of cooking and wood burning related to indoor emissions needs to be investigated further. The available data indicate that many PAH will be distributed between both particles and the gas phase. Therefore, new techniques for simultaneously sampling PAH in both phases are required for the indoor environment and personal monitoring studies. These will increase our understanding of the distribution of each component and increase the accuracy of exposure and risk assessments conducted for Total PAH. A strategy (THEES) has been developed for the measurement of BaP exposure from multiple pathways. It should be extended to other PAH, which will assist in quantifying the significance of indoor air related exposures. The inhalation exposures could be derived from indoor combustion sources, penetration of outdoor air indoors, and personal activities, such as cooking and smoking. The reactivity of PAH requires further investigation, since it appears that a number of nitro-PAH will be produced. Some of the resulting compounds will need to be factored into PAH exposure assessments.

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

    NASA Astrophysics Data System (ADS)

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

    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.

  20. Hydrocarbon group type analyzer system for the rapid determination of saturates, olefins, and aromatics in hydrocarbon distillate products

    SciTech Connect

    Hayes, P.C. Jr.; Anderson, S.D.

    1986-10-01

    A dielectric constant (DC) detector for high-performance liquid chromatography (HPLC) is the basis of a rapid and accurate hydrocarbon group type analysis. This novel method can determine saturates, olefins, and total aromatics in hydrocarbon liquids with distillation end points (ASTM D 2887) of at least 400 /sup 0/C. The HPLC separation is achieved by using a single, olefin-selective column, a backflush valve, and Freon 123 as the mobile phase. The DC detector ensures a genuine uniformity of response (less than 2.5% relative standard deviation) for each hydrocarbon group type independent of the carbon number distribution of the sample. Unity response factors are sufficient. On the basis of complex solutions of hydrocarbon standards, the accuracy for each structural group type is within 1% absolute. The chromatographic limit of detection is less than 0.5 vol % (800 ng) for the last eluting hydrocarbon group, i.e., the olefins.

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

    PubMed

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

    2015-03-01

    The agronomic benefit of biochar has attracted widespread attention to biochar-based fertilizers. However, the inevitable presence of polycyclic aromatic hydrocarbons in biochar is a matter of concern because of the health and ecological risks of these compounds. The strong adsorption of polycyclic aromatic hydrocarbons to biochar complicates their analysis and extraction from biochar-based fertilizers. In this study, we optimized and validated a method for determining the 16 priority polycyclic aromatic hydrocarbons in biochar-based fertilizers. Results showed that accelerated solvent extraction exhibited high extraction efficiency. Based on a Box-Behnken design with a triplicate central point, accelerated solvent extraction was used under the following optimal operational conditions: extraction temperature of 78°C, extraction time of 17 min, and two static cycles. The optimized method was validated by assessing the linearity of analysis, limit of detection, limit of quantification, recovery, and application to real samples. The results showed that the 16 polycyclic aromatic hydrocarbons exhibited good linearity, with a correlation coefficient of 0.996. The limits of detection varied between 0.001 (phenanthrene) and 0.021 mg/g (benzo[ghi]perylene), and the limits of quantification varied between 0.004 (phenanthrene) and 0.069 mg/g (benzo[ghi]perylene). The relative recoveries of the 16 polycyclic aromatic hydrocarbons were 70.26-102.99%. PMID:25546393

  2. Determination of polycyclic aromatic hydrocarbons in dry tea

    PubMed Central

    ADISA, AFOLABI; JIMENEZ, ANGELICA; WOODHAM, CARA; ANTHONY, KEVIN; NGUYEN, THAO; SALEH, MAHMOUD A.

    2016-01-01

    Twenty-eight different tea samples sold in the United States were evaluated using high-performance liquid chromatography (HPLC) with fluorescence detection (FLD) for their contamination with polycyclic aromatic hydrocarbons (PAHs). Many PAHs exhibit carcinogenic, mutagenic, and teratogenic properties and have been related to several kinds of cancer in man and experimental animals. The presence of PAHs in environmental samples such as water, sediments, and particulate air has been extensively studied, but food samples have received little attention. Eighteen PAHs congeners were analyzed, with percentage recovery higher than 85%. Contamination expressed as the sum of the 18 analyzed PAHs was between 101 and 1337 μg/kg on dry mass and the average contents in all of the 28 examined samples was 300 μg/kg on dry mass. Seven of the congeners were found in all samples with wide ranges of concentrations as follows: fluorene (7–48 μg/kg), anthracene (1–31 μg/kg), pyrene (1–970 μg/kg), benzo(a)anthracene (1–18 μg/kg) chrysene (17–365 μg/kg), benzo(a)pyrene (1–29 μg/kg), and indeno(1,2,3-cd)pyrene (4–119 μg/kg). The two most toxic congeners benzo(a)pyrene and dibenzo(a,h)anthracene were found at high concentrations only in Earl Grey Twinnings, Earl Grey Harney& Sons Fine Teas, and Chai Ultra Spice Black Tea Twinnings. Six PAH congeners are considered as suspected carcinogens (U.S.EPA), formed the basis of the estimation of the toxic equivalent (TEQ), Chai Ultra-Spice Black Tea Twinnings had the highest TEQ (110.9) followed by two grey tea samples, Earl Grey Harney & Sons Fine Tea (57.7) and Earl Grey Twinnings (54.5). Decaffeinated grey teas had the lowest TEQs, decaffeinated Earl Grey Bigelow (9.4) and Green Tea Honey Lemon Decaffeinated Lipton (9.6). PMID:26065515

  3. An Emission Inventory of Polycyclic Aromatic Hydrocarbons in China

    NASA Astrophysics Data System (ADS)

    Mu, Xilong; Zhu, Xianlei; Wang, Xuesong

    2015-04-01

    Polycyclic Aromatic Hydrocarbons (PAHs) are among the most dangerous compounds due to their high carcinogenic and mutagenic character. Emission inventory provides the primary data to account for the sources of ambient PAHs and server as a necessary database for effective PAHs pollution control. China is experiencing fast economic growth and large energy consumption, which might result in a large amount of PAHs anthropogenic emissions. Therefore, based on the previous studies and combined recently field emission measurements as well as socio-economic activity data, the development of a nationwide PAHs emission inventory is needed. In this work, the emission inventory of 16 PAHs listed as U.S. Environmental Protection Agency priority pollutants in China in the year 2012 is compiled. The emission amounts of PAHs were estimated as annual rates of emission-related activities multiplied by respective emission factors. The activities such as fuel consumption, including fossil fuel and biofuel, and socio-economic statistics were obtained from yearbook released by Chinese central government and/or provincial governments, as well as related industry reports. Emission factors were derived from the related literature. Recently reported emission factors from local measurements were used. The total emissions of PAHs were 120611 ton in 2012. In China, PAHs were emitted predominantly from domestic combustion of coal and biofuel, coking industry and motor vehicles, accounting for 72% of the total amount. PAHs emission profiles were significantly different between China and the other countries. The emission profile in China featured a relatively higher portion of high molecular weight species with carcinogenic potential due to large contributions of domestic combustion and coking industry. Domestic combustion of straw, coal and firewood emitted 19464 ton, 8831 ton, and 5062 ton of PAHs, respectively, which were much higher than those in other countries. Emission per capita showed geographical variations. In general, the southeastern provinces of China were characterized by higher emission per capita. The PAHs emissions were higher in the winter than those in the summer. In the following work, the above emission inventory will be used as an input to Chemical Transport Model to simulate the ambient PAHs concentrations in China, and the uncertainty of the inventory will be assessed based on the comparisons between simulated concentrations and available observations. Acknowledgement This work was financially supported by the Natural Science Foundation of China (Grant No. 41175102). Corresponding author: Xuesong Wang

  4. Ecotoxicity of a polycyclic aromatic hydrocarbon (PAH)-contaminated soil.

    PubMed

    Eom, I C; Rast, C; Veber, A M; Vasseur, P

    2007-06-01

    Soil samples from a former cokery site polluted with polycyclic aromatic hydrocarbons (PAHs) were assessed for their toxicity to terrestrial and aquatic organisms and for their mutagenicity. The total concentration of the 16 PAHs listed as priority pollutants by the US Environmental Protection Agency (US-EPA) was 2634+/-241 mg/kgdw in soil samples. The toxicity of water-extractable pollutants from the contaminated soil samples was evaluated using acute (Vibrio fischeri; Microtox test, Daphnia magna) and chronic (Pseudokirchneriella subcapitata, Ceriodaphnia dubia) bioassays and the EC values were expressed as percentage water extract in the test media (v/v). Algal growth (EC50-3d=2.4+/-0.2% of the water extracts) and reproduction of C. dubia (EC50-7d=4.3+/-0.6%) were the most severely affected, compared to bacterial luminescence (EC50-30 min=12+/-3%) and daphnid viability (EC50-48 h=30+/-3%). The Ames and Mutatox tests indicated mutagenicity of water extracts, while no response was found with the umu test. The toxicity of the soil samples was assessed on the survival and reproduction of earthworms (Eisenia fetida) and collembolae (Folsomia candida), and on the germination and growth of higher plants (Lactuca sativa L.: lettuce and Brassica chinensis J.: Chinese cabbage). The EC50 values were expressed as percentage contaminated soil in ISO soil test medium (weight per weight-w/w) and indicated severe effects on reproduction of the collembola F. candida (EC50-28 d=5.7%) and the earthworm E. fetida (EC50-28 d=18% and EC50-56 d=8%, based on cocoon and juvenile production, respectively). Survival of collembolae was already affected at a low concentration of the contaminated soil (EC50-28 d=11%). The viability of juvenile earthworms was inhibited at much lower concentrations of the cokery soil (EC50-14 d=28%) than the viability of adults (EC50-14 d=74%). Only plant growth was inhibited (EC50-17d=26%) while germination was not. Chemical analyses of water extracts allowed us to identify inorganic water-extractable pollutants as responsible for toxicity on aquatic species, especially copper for effects on D. magna and C. dubia. The soil toxicity on collembolae and earthworms could be explained by 4 PAH congeners-fluorene, phenanthrene, pyrene, and fluoranthene. Yet, toxicity of the cokery soil as a whole was much lower than toxicity that could be deduced from the concentration of each congener in spiked soils, indicating that pollutants in the soil became less bioavailable with ageing. PMID:17382389

  5. Intermediates in the Formation of Aromatics in Hydrocarbon Combustion

    NASA Technical Reports Server (NTRS)

    Walch, Stephen P.; Langhoff, S. R. (Technical Monitor)

    1994-01-01

    The formation of the first benzene ring is believed to be the rate limiting step in soot formation. Two different mechanisms have been proposed for formation of cyclic C6 species. The first involves the reaction of two acetylenes to give CH2CHCCH (vinyl acetylene), the loss of a H to give CHCHCCH (n-C41-13) or CH2CCCH (iso-C4H3), and addition of another acetylene to n-C4H3, followed by ring closure to give phenyl radical. Miller and Melius argue that only n-C4H3 leads to phenyl radical and since iso-C4H3 is more stable than n-C4H3 this mechanism is unlikely. An alternative mechanism proposed by them is formation of benzene from the dimerization of two CH2CCH (propargyl) radicals (formed by the reaction of singlet methylene with C2H2). We report reaction pathways and accurate energetics (from CASSCF/internally contracted CI calculations) for the reactions of CH(pi-2) and CH2-1 with acetylene, the reaction of vinylidene with acetylene, and the reaction of n-C4H3 and iso-C4H3 with acetylene. These calculations identify two new reactive intermediates CHCHCH ( a A"-2 ground state in Cs symmetry; spin coupling is a doublet from three singly occupied orbitals) and CHCCH (B-3 ground state in C2 symmetry) from the reaction of CH with acetylene. These species dimerize with no barrier to form benzene and para-benzyne, respectively. CHCCH is proposed as a reactive intermediate which can add to benzene to give higher polynuclear aromatic hydrocarbons or fullerenes. The addition of a C3H2 unit releases two C-C bond energies and thus the resulting addition product contains sufficient energy to break several CH bonds leading to a reduction in the H to C ratio as the cluster size increases. It is found that iso-C4H3 adds to acetylene to initially give a fulvene radical but that this species rearranges to phenyl radical. Thus, the reaction of acetylene with iso-C4H3 does lead to phenyl radical and the cyclization pathway may also contribute to formation of the initial benzene ring.

  6. DNA adducts and carcinogenicity of nitro-polycyclic aromatic hydrocarbons

    SciTech Connect

    Fu, P.P.; Herreno-Saenz, D.; Von Tungeln, L.S.

    1994-10-01

    We have been interested in the structure-activity relationships of nitro-polycyclic aromatic hydrocarbons (nitro-PAHs), and have focused on the correlation of structural and electronic features with biological activities, including mutagenicity and tumorigenicity. In our studies, we have emphasized 1-, 2-, 3-, and 6-nitrobenzo[a]pyrenes (nitro-B[a]Ps) and related compounds, all of which are derived from the potent carcinogen benzo[a]pyrene. While 1-, 2-, and 3-nitro-B[a]P are potent mutagens in Salmonella, 6-nitro-B[a]P is a weak mutagen. In vitro metabolism of 1- and 3-nitro-B[a]P has been found to generate multiple pathways for mutagenic activation. The formation of the corresponding trans-7,8-dihydrodiols and 7,8,9,10-tetrahydrotetrols suggests that 1- and 3-nitro-B[a]P trans-7,8-diol-anti-9, 10--epoxides are ultimate metabolites of the parent nitro-B[a]Ps. We have isolated a DNA adduct from the reaction between 3-nitro-B[a]P trans-7,8-diol-anti-9, 10-epoxide and calf thymus DNA, and identified it as 10-(deoxyguanosin-N{sup 2}-yl)-7,8,9-trihydroxy-7,8,9,10-tetrahydro-3-nitro-B[a]P. The same adduct was identified from in vitro metabolism of [{sup 3}H]3-nitro-B[a]P by rat liver microsomes in the presence of calf thymus DNA. A DNA adduct of 3-nitro-B[a]P formed from reaction of N-hydroxy-3-amino-B[a]P, prepared in situ with calf thymus DNA was also isolated. This adduct was identified as 6-(deoxyguanosin-N{sup 2}-yl)-3-amino-B[a]P. The same adduct was obtained from incubating DNA with 3-nitro-B[a]P in the presence of the mammalian nitroreductase, xanthine oxidase, and hypoxanthine. 48 refs., 6 figs., 1 tab.

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

    NASA Astrophysics Data System (ADS)

    Xu, H.; Wu, J.; Shi, X.; Sun, Y.

    2014-12-01

    Although bioremediation has been considered as one of the most promising means to remove polycyclic aromatic hydrocarbons (PAHs) from polluted environments, the efficacy of PAHs bioremediation still remains challenged, especially for high molecular weight PAHs (HMW PAHs) and their mixtures. This study was focused on (a) isolation and characterization of pure strain and mixed microbial communities able to degrade HMW PAHs and (b) further evaluation of the ability of the isolated microbes to degrade HMW PAHs mixtures in the absence and presence of indigenous flora. Fluoranthene, benzo[b]fluoranthene and pyrene were selected as the representative HMW PAHs in this study. A pure bacterial strain, identified as Herbaspirillum chlorophenolicum FA1, was isolated from activated sludge. A mixed bacterial community designated as consortium-4 was isolated from petroleum contaminated soils, containing Pseudomonas sp. FbP1、Enterobacter sp. FbP2、Hydrogenophaga sp. FbP3 and Luteolibacter pohnpeiensis. FbP4. To our knowledge, this is the first study to demonstrate that bacterial strains of Herbaspirillum chlorophenolicum FA1 and Luteolibacter pohnpeiensis. FbP4 can also degrade fluoranthene, benzo[b]fluoranthene and pyrene. Experiment results showed that both strain FA1 and consortium-4 could degrade fluoranthene, benzo[b]fluoranthene and pyrene within a wide range of temperature, pH and initial PAHs concentration. Degradation of HMW PAHs mixtures (binary and ternary) demonstrated the interactive effects that can alter the rate and extent of biodegradation within a mixture. The presence of indigenous flora was found to either increase or decrease the degradation of HMW PAHs, suggesting possible synergistic or competition effects. Biodegradation kinetics of HMW PAHs for sole substrates, binary and ternary systems was evaluated, with the purpose to better characterize and compare the biodegradation process of individual HMW PAH and mixtures of HMW PAHs. Results of this study could advance our understanding of HMW PAHs biodegradation and help to develop successful bioremediation strategies. This work was supported by the National Natural Science Foundation of China (41102148), and the Specialized Research Fund for the Doctoral Program of Higher Education of China (20110091120063).

  8. Exposure of Firefighters to Particulates and Polycyclic Aromatic Hydrocarbons

    PubMed Central

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

    2015-01-01

    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 μm) and PM2.5 (2.5 μm 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

  9. Emission of polycyclic aromatic hydrocarbons from medical waste incinerators

    NASA Astrophysics Data System (ADS)

    Lee, Wen-Jhy; Liow, Ming-Chu; Tsai, Perng-Jy; Hsieh, Lien-Te

    This study was conducted on two batch-type medical waste incinerators (MWIs), including the one with a mechanical grate (MG-MWI) and the other with a fixed grate (FG-MWI) for the disposal of general medical waste and special medical waste, respectively. Both incinerators shared the same air-pollution control devices which were installed in series, including one electrostatic precipitator (ESP) and one wet scrubber (WSB). In addition to the investigated emissions of polycyclic aromatic hydrocarbons (PAHs) from both types of MWIs, the PAH removal efficiencies of air-pollution control devices were also included. In this study, the GC/MS technique was used to analyze the concentrations of 21 PAH species contained in the stack flue gas, ESP fly ash, WSB effluent, and incinerating ash. Results show that total-PAHs (i.e., the sum of 21 PAH species) in stack flue gas were dominated by LM-PAHs (i.e., two- to three-ringed PAHs), but in incinerating ash, ESP fly ash and WSB effluent we found that they were dominated by MM-PAHs (i.e., four-ringed PAHs) and HM-PAHs (i.e., five- to seven-ringed PAHs) for both types of MWIs. The above results due to air-pollution control devices used in both types of MWIs had much higher removal efficiencies on both MM-PAHs and HM-PAHs (>78%) than on LM-PAHs (<5%). The emission factors of total-PAHs for MG-MWI (=252,000 μg/kg-waste) were lower than FG-MWI (=856,000 μg/kg-waste), which was probably due to more complete combustion involved in the combustion process of the former than the latter. Nevertheless, the above two emission factors were found consistently higher than the only municipal waste incinerator that was located in the same city (=871 μg/kg-waste, respectively). The above results warrant the need for seeking better technologies for disposing medical waste in the future.

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

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

    During the past 15 years considerable progress in observational techniques has been achieved in the middle-infrared region (5000-500 per centimeter, 2-20 micron), the region where most diagnostic molecular vibrations occur. Spectra of many different astronomical infrared sources, some deeply embedded in dark molecular clouds and others at their edges, are now available. These spectra provide a powerful probe, not only for the identification of interstellar molecules in both the gas and solid phases, but also of the physical and chemical conditions which prevail in these two very different domains. The two lectures will focus on the evidence that polycyclic aromatic hydrocarbons (PAHs) are an important, ubiquitous and abundant interstellar species. PAHs are. extremely stable species which can range in size from a few angstroms across to several hundred angstroms (PAHs are also the building blocks of amorphous carbon particles). This identification rests on the suggestive agreement between the laboratory spectra of PAHs with a set of IR emission bands which emanate from many different sources where ultraviolet starlight impinges on a "dusty" region. The picture is that individual PAHs are first pumped into highly vibrationally excited states and relax by fluorescence at their fundamental vibrational frequencies. That PAHs are a ubiquitous interstellar component has serious ramifications in other spectral regions as well, including the strong extinction in the ultraviolet, and the classic visible diffuse interstellar bands discovered more than 50 years ago (but unexplained to this day) The first part of the course will focus on the interpretation of astronomical spectra. The second lecture will start by showing how recent laboratory data on PAHs taken under realistic interstellar conditions has con borated the PAH hypothesis and led to great insight into the conditions in the PAH containing regions. This lecture will end by reviewing the ever-increasing evidence for 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".

  11. Polycyclic aromatic hydrocarbons in the South American environment.

    PubMed

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

    2007-01-01

    Pollution of the environment with polycyclic aromatic hydrocarbons (PAHs) should be a global concern, especially in urbanized areas. In South American countries, where notable increase in urban populations has been observed in the past few years, reliable information about the pollution status of these urban environments is not always easily accessible, and therefore an effort to collect updated information is required. This review attempts to contribute by analyzing the existing information regarding environmental levels of PAHs in some South American countries. A regional trend for environmental PAH information is an uneven contribution, because some countries, such as Bolivia, Peru, Paraguay, and Ecuador, have reported no information at all in the scientific literature, reflecting to a certain extent the different patterns of economic, technical, and scientific development. PAH air monitoring is one of the areas that has received the most attention during the last few years, mainly in Brazil, Chile, and Argentina, where data represent a few geographical areas within the region. PAH levels in air from some urban areas in Argentina, Brazil, and Chile, considered moderate to high (100-1000ng/m3), are probably among the highest values reported in the open literature. Urbanization, vehicle pollution, and wood fires are the principal contributors to the high reported levels. In more temperate areas, a clear distinction is observed between summer and winter levels. PAH monitoring in soils is very limited within the region, with few data available, and most information indicates widespread pollution. In Brazil, values for many representative ecosystems were found. In Chile, data from forestry and agricultural areas indicate in general low concentrations, in spite of a relatively high detection frequency. Pollution levels in soils are highly dependent on their closeness to PAH sources and certain cultural practices (agricultural burnings, forest fires, etc.). Water PAH 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 objectives. PMID:17708070

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

    SciTech Connect

    Deng, L.

    1998-03-27

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

  13. Combined ozonation and biodegradation for remediation of mixtures of polycyclic aromatic hydrocarbons in soil.

    PubMed

    Nam, K; Kukor, J J

    2000-01-01

    A study was conducted to investigate the feasibility of a combined treatment (i.e., ozonation and biodegradation) to overcome the inherent bacterial bioavailability limitation, and hence bioremediation limitation, of polycyclic aromatic hydrocarbons in soil. Ozonation was very efficient in the removal of naphthalene, fluorene, phenanthrene, and anthracene, but not for pyrene, chrysene, and benzo(a)pyrene from soil freshly spiked with the hydrocarbons. A similar result was obtained from coal tar-contaminated soil. Elimination of polycyclic aromatic hydrocarbons increased appreciably in sand containing 0.03% organic carbon, indicating the adverse effect of organic carbon on the efficiency of ozone treatment. In spiked and coal tar-contaminated soils, ozonation followed by biodegradation significantly increased the degradation of various polycyclic aromatic hydrocarbons including chrysene and benzo(a)pyrene which were not degraded by the test bacterial consortium alone. In particular, the effect of the combined treatment was more pronounced in coal tar-contaminated soil than in sterile soil spiked with hydrocarbons, probably due to the augmented biological activity of the introduced consortium. The results suggest that a combined treatment including ozonation and biodegradation may be a promising bioremediation technology in soil contaminated with mixtures of polycyclic aromatic hydrocarbons such as former manufactured gas plant sites. PMID:11194968

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

    PubMed

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

    2013-06-13

    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

  15. Production of aromatic hydrocarbons through catalytic pyrolysis of 5-Hydroxymethylfurfural from biomass.

    PubMed

    Zhao, Yan; Pan, Tao; Zuo, Yong; Guo, Qing-Xiang; Fu, Yao

    2013-11-01

    Catalytic pyrolysis of 5-Hydroxymethylfurfural (HMF) was conducted on a fixed bed reactor at atmospheric pressure. HMF could be converted into aromatic hydrocarbons through catalytic pyrolysis. The catalysts and reaction conditions were both critical in maximizing the aromatic hydrocarbons selectivity. Four catalysts, β-zeolite, HZSM-5, Ga/HZSM and In/HZSM were tested in this study. HZSM-5 (Si/Al=50) was found to be the most effective catalyst in both reactivity and selectivity among these catalysts. Under the reaction temperature of 600 °C, the highest carbon yield of 48.99% of aromatic hydrocarbons was achieved from catalytic pyrolysis HMF with HZSM-5 (Si/Al=50) as catalyst. Moreover, the HZSM-5 (Si/Al=50) catalyst was recycled for five times without shown deactivation of the catalyst. PMID:23994304

  16. Analysis of Intervention Strategies for Inhalation Exposure to Polycyclic Aromatic Hydrocarbons and Associated Lung Cancer Risk Based on a Monte Carlo Population Exposure Assessment Model

    PubMed Central

    Zhou, Bin; Zhao, Bin

    2014-01-01

    It is difficult to evaluate and compare interventions for reducing exposure to air pollutants, including polycyclic aromatic hydrocarbons (PAHs), a widely found air pollutant in both indoor and outdoor air. This study presents the first application of the Monte Carlo population exposure assessment model to quantify the effects of different intervention strategies on inhalation exposure to PAHs and the associated lung cancer risk. The method was applied to the population in Beijing, China, in the year 2006. Several intervention strategies were designed and studied, including atmospheric cleaning, smoking prohibition indoors, use of clean fuel for cooking, enhancing ventilation while cooking and use of indoor cleaners. Their performances were quantified by population attributable fraction (PAF) and potential impact fraction (PIF) of lung cancer risk, and the changes in indoor PAH concentrations and annual inhalation doses were also calculated and compared. The results showed that atmospheric cleaning and use of indoor cleaners were the two most effective interventions. The sensitivity analysis showed that several input parameters had major influence on the modeled PAH inhalation exposure and the rankings of different interventions. The ranking was reasonably robust for the remaining majority of parameters. The method itself can be extended to other pollutants and in different places. It enables the quantitative comparison of different intervention strategies and would benefit intervention design and relevant policy making. PMID:24416436

  17. Analysis of intervention strategies for inhalation exposure to polycyclic aromatic hydrocarbons and associated lung cancer risk based on a Monte Carlo population exposure assessment model.

    PubMed

    Zhou, Bin; Zhao, Bin

    2014-01-01

    It is difficult to evaluate and compare interventions for reducing exposure to air pollutants, including polycyclic aromatic hydrocarbons (PAHs), a widely found air pollutant in both indoor and outdoor air. This study presents the first application of the Monte Carlo population exposure assessment model to quantify the effects of different intervention strategies on inhalation exposure to PAHs and the associated lung cancer risk. The method was applied to the population in Beijing, China, in the year 2006. Several intervention strategies were designed and studied, including atmospheric cleaning, smoking prohibition indoors, use of clean fuel for cooking, enhancing ventilation while cooking and use of indoor cleaners. Their performances were quantified by population attributable fraction (PAF) and potential impact fraction (PIF) of lung cancer risk, and the changes in indoor PAH concentrations and annual inhalation doses were also calculated and compared. The results showed that atmospheric cleaning and use of indoor cleaners were the two most effective interventions. The sensitivity analysis showed that several input parameters had major influence on the modeled PAH inhalation exposure and the rankings of different interventions. The ranking was reasonably robust for the remaining majority of parameters. The method itself can be extended to other pollutants and in different places. It enables the quantitative comparison of different intervention strategies and would benefit intervention design and relevant policy making. PMID:24416436

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

    PubMed Central

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

    2004-01-01

    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. PMID:15121521

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

    PubMed Central

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

    1999-01-01

    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 PMID:10464072

  20. Early-Life Exposure to Polycyclic Aromatic Hydrocarbons and ADHD Behavior Problems

    PubMed Central

    Perera, Frederica P.; Chang, Hsin-wen; Tang, Deliang; Roen, Emily L.; Herbstman, Julie; Margolis, Amy; Huang, Tzu-Jung; Miller, Rachel L.; Wang, Shuang; Rauh, Virginia

    2014-01-01

    Importance Polycyclic aromatic hydrocarbons are widespread urban air pollutants from combustion of fossil fuel and other organic material shown previously to be neurotoxic. Objective In a prospective cohort study, we evaluated the relationship between Attention Deficit Hyperactivity Disorder behavior problems and prenatal polycyclic aromatic hydrocarbon exposure, adjusting for postnatal exposure. Materials and Methods Children of nonsmoking African-American and Dominican women in New York City were followed from in utero to 9 years. Prenatal polycyclic aromatic hydrocarbon exposure was estimated by levels of polycyclic aromatic hydrocarbon- DNA adducts in maternal and cord blood collected at delivery. Postnatal exposure was estimated by the concentration of urinary polycyclic aromatic hydrocarbon metabolites at ages 3 or 5. Attention Deficit Hyperactivity Disorder behavior problems were assessed using the Child Behavior Checklist and the Conners Parent Rating Scale- Revised. Results High prenatal adduct exposure, measured by elevated maternal adducts was significantly associated with all Conners Parent Rating Scale-Revised subscales when the raw scores were analyzed continuously (N = 233). After dichotomizing at the threshold for moderately to markedly atypical symptoms, high maternal adducts were significantly associated with the Conners Parent Rating Scale-Revised DSM-IV Inattentive (OR = 5.06, 95% CI [1.43, 17.93]) and DSM-IV Total (OR = 3.37, 95% CI [1.10, 10.34]) subscales. High maternal adducts were positivity associated with the DSM-oriented Attention Deficit/Hyperactivity Problems scale on the Child Behavior Checklist, albeit not significant. In the smaller sample with cord adducts, the associations between outcomes and high cord adduct exposure were not statistically significant (N = 162). Conclusion The results suggest that exposure to polycyclic aromatic hydrocarbons encountered in New York City air may play a role in childhood Attention Deficit Hyperactivity Disorder behavior problems. PMID:25372862

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    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 μm) 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.

  2. Heterogeneous Reactions of Polycyclic Aromatic Hydrocarbons on Atmospheric and Terrestrial Surfaces

    NASA Astrophysics Data System (ADS)

    Simonich, S. L.

    2014-12-01

    The heterogeneous reactions of five higher molecular weight polycyclic aromatic hydrocarbons (PAHs), benzo[a]pyrene-d12 (BaP-d12), benzo(k)fluoranthene-d12 (BkF-d12), benzo[g,h,i]perylene-d12 (BghiP-d12), dibenzo(a,i)pyrene-d14 (DBaiP-d14), and dibenzo[a,l]pyrene (DalP), with NO2, NO3/N2O5, O3, and OH radicals were investigated in a 7000 L indoor Teflon chamber. Quartz fiber filters (QFF) were used as the reaction surface and substrate and the analyses of parent PAHs and Nitro-PAH (NPAH) products was conducted using electron impact gas chromatographic mass spectrometry (GC/MS) and negative chemical ionization GC/MS. In parallel to the laboratory experiments, a theoretical study was conducted to assist in determining the formation of NPAH isomers based on the OH-radical initiated reaction. The thermodynamic stability of OH-PAH intermediates was used to indicate the position of highest electron density and the most stable NPAH products were synthesized to confirm their identity. NO2 and NO3/N2O5 were the most effective oxidizing agents in transforming PAHs deposited on filters to NPAHs, under the experimental conditions. Reaction of BaP-d12, BkF-d12 and BghiP-d12 resulted in the formation of several mono-nitro PAH isomer product, while the reaction of DalP and DaiP-d14 resulted in the formation of only one mono-nitro PAH isomer product. The direct-acting mutagenicity of the products increased the most after NO3/N2O5 exposure, particularly for BkF-d12 in which the formation of dinitro- PAHs was observed. In addition, the degradation of particulate matter (PM)-bound PAHs by heterogeneous reaction with OH radicals, O3, NO3/N2O5 was also studied. Ambient PM samples collected from Beijing, China and Riverside, California were exposed in an indoor chamber under simulated trans-Pacific atmospheric transport conditions and the formation of NPAHs was studied. NPAHs were most effectively formed during the NO3/N2O5 exposure and, for all exposures, there was no significant formation of 2-nitrofluoranthene or 2-nitropyrene, suggesting that heterogeneous reactions predominated. The importance of this research with respect to atmospheric long-range transport of PM-bound PAHs and heterogeneous reaction of PAHs on terrestrial surfaces will be discussed.

  3. Non-linear, cata-Condensed, Polycyclic Aromatic Hydrocarbon Materials: A Generic Approach and Physical Properties.

    PubMed

    Haire, Barnaby T; Heard, Kane W J; Little, Mark S; Parry, Adam V S; Raftery, James; Quayle, Peter; Yeates, Stephen G

    2015-07-01

    A generic approach to the regiospecific synthesis of halogenated polycyclic aromatics is made possible by the one- or two-directional benzannulation reactions of readily available (ortho-allylaryl)trichloroacetates (the "BHQ" reaction). Palladium-catalysed cross-coupling reactions of the so-formed haloaromatics enable the synthesis of functionalised polycyclic aromatic hydrocarbons (PAHs) with surgical precision. Overall, this new methodology enables the facile mining of chemical space in search of new electronic functional materials. PMID:26059760

  4. Non-linear, cata-Condensed, Polycyclic Aromatic Hydrocarbon Materials: A Generic Approach and Physical Properties

    PubMed Central

    Haire, Barnaby T; Heard, Kane W J; Little, Mark S; Parry, Adam V S; Raftery, James; Quayle, Peter; Yeates, Stephen G

    2015-01-01

    A generic approach to the regiospecific synthesis of halogenated polycyclic aromatics is made possible by the one- or two-directional benzannulation reactions of readily available (ortho-allylaryl)trichloroacetates (the “BHQ” reaction). Palladium-catalysed cross-coupling reactions of the so-formed haloaromatics enable the synthesis of functionalised polycyclic aromatic hydrocarbons (PAHs) with surgical precision. Overall, this new methodology enables the facile mining of chemical space in search of new electronic functional materials. PMID:26059760

  5. Determination of total and polycyclic aromatic hydrocarbons in aviation jet fuel.

    PubMed

    Bernabei, M; Reda, R; Galiero, R; Bocchinfuso, G

    2003-01-24

    The aviation jet fuel widely used in turbine engine aircraft is manufactured from straight-run kerosene. The combustion quality of jet fuel is largely related to the hydrocarbon composition of the fuel itself; paraffins have better burning properties than aromatic compounds, especially naphthalenes and light polycyclic aromatic hydrocarbons (PAHs), which are characterised as soot and smoke producers. For this reason the burning quality of fuel is generally measured as smoke fermation. This evaluation is carried out with UV spectrophotometric determination of total naphthalene hydrocarbons and a chromatographic analysis to determine the total aromatic compounds. These methods can be considered insufficient to evaluate the human health impact of these compounds due to their inability to measure trace (ppm) amounts of each aromatic hyrcarbon and each PAH in accordance with limitations imposed because of their toxicological properties. In this paper two analytical methods are presented. Both are based on a gas chromatographic technique with a mass detector operating in be selected ion monitoring mode. The first method was able to determine more than 60 aromatic hydrocarbons in a fuel sample in a 35-min chromatographic run, while the second was able to carry out the analysis of more than 30 PAHs in a 40-min chromatographic run. The linearity and sensitivity of the methods in measuring these analytes at trace levels are described. PMID:12580487

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

    SciTech Connect

    1995-10-01

    The bibliography contains citations concerning the removal of polycyclic aromatic hydrocarbons from contaminated soil or water. The chemical or biological processes that destroy these contaminants or reduce their toxicity are discussed. Techniques include treatments used in above-ground reactors or in situ detoxification of contaminated sites. The citations examine the relationship between the chemical structure of polycyclic aromatic hydrocarbons and rate of decomposition; selection of the most effective microorganisms for biological degradation; and factors which can accelerate or inhibit degradation.(Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  7. Shakedown operation of group of units for aromatic hydrocarbon production at the Novopolotsk petroleum refinery

    SciTech Connect

    Rudkovskii, A.D.; Chesnovitskii, K.G.; Koroleva, M.I.; Sulimov, A.D.; Teteruk, V.G.

    1983-03-01

    This article describes how technical xylene and C/sub 9/ aromatic hydrocarbons are produced in catalytic reformers operated in conjunction with diethylene glycol extraction units. In the operation of the unit, the greatest difficulties were encountered in purification of the p-xylene, owing to frequent mechanical failures of the equipment of the pulsed columns due to hydraulic shock and unstable operation under the process conditions required to obtain a product with a purity above 99%. As a result of the successful shakedown operations of individual aromatic hydrocarbons, the yields of commercial products (ethylbenzene, p-xylene, o-xylene, pseudocumene) have amounted to 76.9% of the technical xylene feed.

  8. Polycyclic Aromatic Hydrocarbons in an industrialized urban area

    NASA Astrophysics Data System (ADS)

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

    2009-04-01

    Urbanization, agricultural intensification and industrialization are contributing to erosion, local and diffuse contamination and sealing of soil surfaces, resulting in soil quality degradation. Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in urban environments and considered good markers of anthropogenic activities such as traffic, industry, domestic heating and agriculture. Although they are subject to biodegradation and photodegradation, once in the soil, they tend to bind to the soil organic fraction. Estarreja is a small coastal town in the Northwestern Portuguese coast, with a close relation with the lagoon of Aveiro which supports a variety of biotopes (channels, islands with vegetation, mudflats, salt marshes and agricultural fields) of important ecological value. It supports an intensive and diversified agriculture, a variety of heavy and light industries and a population of about half a million people which is dependent on this resource. This is a very industrialized area, due to its five decades of chemical industry. This study aims to assess the impact of the urbanization and of the chemical industry in PAHs distribution. The survey and sampling method were based on pre-interpreted maps, aerial photographs, and directly checked in the field, in order to get an overall characterization of the area. Topsoils were collected from 34 sites, considering different land uses. Five land uses were chosen: ornamental gardens, parks, roadsides, forest and agricultural. Parameters such as soil pH (ISO method 10390:1994), total C, N, H, S percentages (microanalyser LECO, CNHS-932), organic matter (LOI at 430°), particle size distribution (Micromeritics® Sedigraph 5100), cation exchange capacity and exchangeable bases, were determined in order to have a general characterization of soil. Determination of the 16 EPA PAHs in soils was performed by GC/MS after a Soxhlet extraction and an alumina clean-up of extracts. Procedure blanks, duplicates and reference 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

  9. Peat fires as source of polycyclic aromatic hydrocarbons in soils

    NASA Astrophysics Data System (ADS)

    Tsibart, Anna

    2013-04-01

    Polycyclic aromatic hydrocarbons (PAHs) arrive from pyrogenic sources including volcanism and the combustion of oil products and plant materials. The production of PAHs during the combustion of plant materials was considered in a number of publications, but their results were mainly obtained in laboratory experiments. Insufficient data are available on the hightemperature production of PAHs in environmental objects. For example, natural fires are frequently related to the PAH sources in landscapes, but very little factual data are available on this topic. On Polistovskii reserve (Russia, Pskov region) the soil series were separated depending on the damage to the plants; these series included soils of plots subjected to fires of different intensities, as well as soils of the background plots. The series of organic and organomineral soils significantly differed in their PAH distributions. In this series, the concentration of PAHs in the upper horizons of the peat soils little varied or slightly decreased, but their accumulation occurred at a depth of 5-10 or 10-20 cm in the soils after the fires. For example, in the series of high moor soils, the content of PAHs in the upper horizons remained almost constant; significant differences were observed in the subsurface horizons: from 2 ng/g in the background soil to 70 ng/g after the fire. In the upper horizons of the oligotrophic peat soils under pine forests, the total PAH content also varied only slightly. At the same time, the content of PAHs in the soil series increased from 15 to 90 ng/g with the increasing pyrogenic damage to the plot. No clear trends of the PAH accumulation were recorded in the organomineral soils. The content of PAHs in the soddy-podzolic soil subjected to fire slightly decreased (from 20 to 10 ng/g) compared to the less damaged soil. In peat fires, the access of oxygen to the fire zone is lower than in forest fires. The oxygen deficit acts as a factor of the organic fragments recombination and 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.

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

    NASA Astrophysics Data System (ADS)

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

    2016-02-01

    Substitution of methyl groups onto the aromatic ring determines the secondary organic aerosol (SOA) formation from the monocyclic aromatic hydrocarbon precursor (SOA yield and chemical composition). This study links the number of methyl groups on the aromatic ring to SOA formation from monocyclic aromatic hydrocarbons photooxidation under low-NOx conditions (HC/NO > 10 ppbC : ppb). Monocyclic aromatic hydrocarbons with increasing numbers of methyl groups are systematically studied. SOA formation from pentamethylbenzene and hexamethylbenzene are reported for the first time. A decreasing SOA yield with increasing number of methyl groups is observed. Linear trends are found in both f44 vs. f43 and O / C vs. H / C for SOA from monocyclic aromatic hydrocarbons with zero to six methyl groups. An SOA oxidation state predictive method based on benzene is used to examine the effect of added methyl groups on aromatic oxidation under low-NOx conditions. Further, the impact of methyl group number on density and volatility of SOA from monocyclic aromatic hydrocarbons is explored. Finally, a mechanism for methyl group impact on SOA formation is suggested. Overall, this work suggests that, as more methyl groups are attached on the aromatic ring, SOA products from these monocyclic aromatic hydrocarbons become less oxidized per mass/carbon on the basis of SOA yield or chemical composition.

  11. Surface enhanced Raman spectroscopy of polycyclic aromatic hydrocarbons and molecular asphaltenes

    NASA Astrophysics Data System (ADS)

    Andrews, A. Ballard; Wang, Dongxing; Marzec, Katarzyna M.; Mullins, Oliver C.; Crozier, Kenneth B.

    2015-01-01

    We describe, for the first time to the best of our knowledge, the acquisition of surface enhanced Raman spectra (SERS) of asphaltenes. SERS is an especially sensitive probe for aromatic carbon making it ideal to investigate the enigmatic polycyclic aromatic hydrocarbons (PAHs) of asphaltenes, the heaviest, most aromatic components of crude oil. SERS spectra of a known PAH model compound and of asphaltene samples are compared to density functional theory (DFT) calculations of PAH structures. This combination of experimental and theoretical methods represents an advance in the characterization of asphaltenes and other complex mixtures.

  12. Oxidative decomposition of aromatic hydrocarbons by electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Han, Do-Hung; Stuchinskaya, Tatiana; Won, Yang-Soo; Park, Wan-Sik; Lim, Jae-Kyong

    2003-05-01

    Decomposition of aromatic volatile organic compounds (VOCs) under electron beam irradiation was studied in order to examine the kinetics of the process, to characterize the reaction product distribution and to develop a process of waste gas control technology. Toluene, ethylbenzene, o-, m-, p-xylenes and chlorobenzene were used as target materials. The experiments were carried out at doses ranging from 0.5 to 10 kGy, using a flow reactor utilized under electron beam irradiation. Maximum degrees of decomposition carried out at 10 kGy in air environment were 55-65% for “non-chlorinated” aromatic VOC and 85% for chlorobenzene. It was found that a combination of aromatic pollutants with chlorobenzene would considerably increase the degradation value up to nearly 50% compared to the same compounds in the absence of chlorine groups. Based on our experimental observation, the degradation mechanism of the aromatic compounds combined with chloro-compound suggests that a chlorine radical, formed from EB irradiation, induces a chain reaction, resulting in an accelerating oxidative destruction of aromatic VOCs.

  13. Aromatic hydrocarbons of mineral oil origin in foods: method for determining the total concentration and first results.

    PubMed

    Biedermann, Maurus; Fiselier, Katell; Grob, Koni

    2009-10-14

    An online normal phase high-performance liquid chromatography (HPLC)-gas chromatography (GC)-flame ionization detection (FID) method was developed for the determination of the total concentration of the aromatic hydrocarbons of mineral oil origin with up to at least five rings in edible oils and other foods. For some samples, the olefins in the food matrix were epoxidized to increase their polarity and remove them from the fraction of the aromatic hydrocarbons. This reaction was carefully optimized, because also some aromatics tend to react. To reach a detection limit of around 1 mg kg(-1) in edible oils, an off-line enrichment was introduced. Some foods contained elevated concentrations of white paraffin oils (free of aromatics), but the majority of the mineral oils detected in foods were of technical grade with 20-30% aromatic hydrocarbons. Many foods contained mineral aromatic hydrocarbons in excess of 1 mg kg(-1). PMID:19728727

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

    PubMed

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

    2006-09-01

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

  15. Coal-tar-based pavement sealcoat, polycyclic aromatic Hydrocarbons (PAHs), and environmental health

    USGS Publications Warehouse

    Mahler, B.J.; Van Metre, P.C.

    2011-01-01

    Studies by the U.S. Geological Survey (USGS) have identified coal-tar-based sealcoat-the black, viscous liquid sprayed or painted on asphalt pavement such as parking lots-as a major source of polycyclic aromatic hydrocarbon (PAH) contamination in urban areas for large parts of the Nation. Several PAHs are suspected human carcinogens and are toxic to aquatic life.

  16. Examination of Apollo 17 surface fines for porphyrins and aromatic hydrocarbons

    NASA Technical Reports Server (NTRS)

    Rho, J. H.

    1974-01-01

    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.

  17. Particle in a Disk: A Spectroscopic and Computational Laboratory Exercise Studying the Polycyclic Aromatic Hydrocarbon Corannulene

    ERIC Educational Resources Information Center

    Frey, E. Ramsey; Sygula, Andrzej; Hammer, Nathan I.

    2014-01-01

    This laboratory exercise introduces undergraduate chemistry majors to the spectroscopic and theoretical study of the polycyclic aromatic hydrocarbon (PAH), corannulene. Students explore the spectroscopic properties of corannulene using UV-vis and Raman vibrational spectroscopies. They compare their experimental results to simulated vibrational

  18. 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 ...

  19. Determination of polycyclic aromatic hydrocarbons in biochar and biochar amended soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A method for the determination of the 16 USEPA polycyclic aromatic hydrocarbons (PAHs) in biochar and soil amended with biochar was developed. Samples were Soxhlet extracted with acetone:cyclohexane 1:1, and PAHs were analysed by GC-MS after silica gel clean-up. In a comparative study based on reflu...

  20. Degradation and utilization of polycyclic aromatic hydrocarbons by indigenous soil bacteria

    SciTech Connect

    Stetzenbach, L.D.A.

    1986-01-01

    The persistence of industrially derived polycyclic aromatic hydrocarbons in the subsurface may be significantly affected by the metabolism of soil bacteria. This study was conducted to determine the ability of indigenous soil bacteria to decrease the concentration of four polycyclic aromatic hydrocarbons (naphthalene, fluorene, anthracene, and pyrene) and to utilize the compounds as a substrate for growth. Soil cores from petroleum contaminated and noncontaminated sites contained 10/sup 5/-10/sup 7/ viable microorganisms per gram dryweight of soil. Gram negative rod-shaped bacteria predominated. Decreases in the concentration of the four polycyclic aromatic hydrocarbons were observed during incubation with bacterial isolates in aqueous suspension by the use of high performance liquid chromatography. Corresponding increases in bacterial numbers indicated utilization of the compounds as a carbon source. Soil samples from the contaminated sites contained greater numbers of bacteria utilizing anthracene and pyrene than soil samples from uncontaminated sites. Degradation rates of the four polycyclic aromatic hydrocarbons were related to the compound, its concentration, and the bacterium. Biodegradation of pyrene was positively correlated with the presence of oxygen. Pyrene was biodegraded by an Acinetobacter sp. under aerobic conditions but not under anaerobic or microaerophilic conditions. Studies with radiolabeled /sup 14/C-anthracene demonstrated utilization of the labeled carbon as a source of carbon by viable bacterial cells in aqueous suspension. Incorporation of /sup 14/C into cellular biomass however was not observed during incubation of /sup 14/C-anthracene in soil.

  1. 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...

  2. 75 FR 8937 - Development of a Relative Potency Factor (RPF) Approach for Polycyclic Aromatic Hydrocarbon (PAH...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-26

    ... AGENCY Development of a Relative Potency Factor (RPF) Approach for Polycyclic Aromatic Hydrocarbon (PAH... for the external review draft document titled, ``Development of a Relative Potency Factor (RPF... developing human health assessments for inclusion in the IRIS database. The purpose of the listening...

  3. POLYCYCLIC AROMATIC HYDROCARBON FORMATION IN OPPOSED FLOW DIFFUSION FLAMES OF ETHANE. (R825412)

    EPA Science Inventory

    Abstract

    The effect of fuel-side carbon density on the levels of polycyclic aromatic hydrocarbon (PAH) formation in atmospheric pressure, opposed flow, ethane diffusion flames has been studied using heated micro-probe sampling and gas chromatography/mass spectrometry (...

  4. CHEMISTRY OF SECONDARY ORGANIC AEROSOL FORMATION FROM THE OXIDATION OF AROMATIC HYDROCARBONS

    EPA Science Inventory

    The experimental data obtained in this project will include reaction rate constants, product branching ratios, and yields of gas-phase and particle-phase products and SOA from OH radical-initiated reactions of aromatic hydrocarbons. These data will be used by atmospheric model...

  5. Empirical modeling of soot formation in shock-tube pyrolysis of aromatic hydrocarbons

    NASA Technical Reports Server (NTRS)

    Frenklach, M.; Clary, D. W.; Matula, R. A.

    1986-01-01

    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.

  6. 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...

  7. Production of aromatic hydrocarbons via catalytic pyrolysis of biomass over fe-modified HZSM-5 zeolites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Iron modified HZSM-5 catalysts were prepared by partial ion exchange of NH4ZSM-5 with Fe (II) at three different loadings (1.4, 2.8 and 4.2 wt%), and their effectiveness for producing aromatic hydrocarbons from cellulose, cellobiose, lignin and switchgrass by catalytic pyrolysis were screened using ...

  8. Fluorescence, Absorption, and Excitation Spectra of Polycyclic Aromatic Hydrocarbons as a Tool for Quantitative Analysis

    ERIC Educational Resources Information Center

    Rivera-Figueroa, A. M.; Ramazan, K. A.; Finlayson-Pitts, B. J.

    2004-01-01

    A quantitative and qualitative study of the interplay between absorption, fluorescence, and excitation spectra of pollutants called polycyclic aromatic hydrocarbons (PAHs) is conducted. The study of five PAH displays the correlation of the above-mentioned properties along with the associated molecular changes.

  9. 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 ...

  10. POLYCYCLIC AROMATIC HYDROCARBONS AND PHENOLICS IN FERROUS AND NON-FERROUS WASTE FOUNDRY SANDS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A total of 43 sets of waste sand were collected from ferrous and non-ferrous foundries in the eastern United States. The concentration of organic compounds known as polycyclic aromatic hydrocarbons (PAHs) and phenolics were determined. These compounds are known to be toxic to humans. Since there ...

  11. Toxicity of aromatic polycyclic hydrocarbons. (Latest citations from the Life Sciences Collection database). Published Search

    SciTech Connect

    Not Available

    1993-11-01

    The bibliography contains citations concerning the toxicity and biochemical effects of aromatic polycyclic hydrocarbons. Topics include effects on metabolism and liver activity, cellular responses, binding characteristics, and the occurrence and path of the compounds in food chains. Bioaccumulation studies in specific areas, and isolation and detection techniques are also considered. (Contains 250 citations and includes a subject term index and title list.)

  12. Toxicity of aromatic polycyclic hydrocarbons. (Latest citations from the Life Sciences Collection data base). Published Search

    SciTech Connect

    Not Available

    1992-05-01

    The bibliography contains citations concerning the toxicity and biochemical effects of aromatic polycyclic hydrocarbons. Topics include effects on metabolism and liver activity, cellular responses, binding characteristics, and the occurrence and path of the compounds in food chains. Bioaccumulation studies in specific areas, and isolation and detection techniques are also considered. (Contains 250 citations and includes a subject term index and title list.)

  13. 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...

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 40 CFR Table 2c to Subpart E of... - Reactivity Factors for Aromatic Hydrocarbon Solvent Mixtures

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 5 2011-07-01 2011-07-01 false Reactivity Factors for Aromatic Hydrocarbon Solvent Mixtures 2C Table 2C to Subpart E of Part 59 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL VOLATILE ORGANIC COMPOUND EMISSION...

  20. 40 CFR Table 2c to Subpart E of... - Reactivity Factors for Aromatic Hydrocarbon Solvent Mixtures

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 5 2010-07-01 2010-07-01 false Reactivity Factors for Aromatic Hydrocarbon Solvent Mixtures 2C Table 2C to Subpart E of Part 59 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL VOLATILE ORGANIC COMPOUND EMISSION...

  1. CHARACTERIZATION OF EMISSIONS OF PAH'S (POLYNUCLEAR AROMATIC HYDROCARBON) FROM RESIDENTIAL COAL-FIRED SPACE HEATERS

    EPA Science Inventory

    The paper gives results of a joint emissions testing and analysis program--the U.S. EPA and the State of Vermont--to determine polynuclear aromatic hydrocarbon (PAH), particulate, sulfur dioxide (SO2), and carbon monoxide (CO) emissions from two coal-fired residential space heate...

  2. Genome Sequence of Sphingobium yanoikuyae B1, a Polycyclic Aromatic Hydrocarbon-Degrading Strain

    PubMed Central

    Zhao, Qiang; Wang, Wei; Peng, Huasong; Zhang, Xuehong

    2015-01-01

    Sphingobium yanoikuyae B1 can utilize biphenyl, naphthalene, phenanthrene, toluene, and m-/p-xylene as sole sources of carbon and energy. Here, we present a 5.2-Mb assembly of its genome. An analysis of the genome can provide insights into the mechanisms of polycyclic aromatic hydrocarbon (PAH) degradation and potentially aid in bioremediation applications. PMID:25657282

  3. 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...

  4. Genome Sequence of Rhodococcus opacus Strain R7, a Biodegrader of Mono- and Polycyclic Aromatic Hydrocarbons

    PubMed Central

    Zampolli, J.; Presti, I.; Cappelletti, M.; D’Ursi, P.; Orro, A.; Mezzelani, A.; Milanesi, L.

    2014-01-01

    Rhodococcus opacus strain R7 (CIP107348) degrades several mono- and polycyclic aromatic hydrocarbons. Here, we present the high-quality draft genome sequence of strain R7, consisting of 10,118,052 bp, with a G+C content of 67.0%, 9,602 protein-coding genes, and 62 RNAs genes. PMID:25146139

  5. CALCULATION OF ELECTRON AFFINITIES OF POLYCYCLIC AROMATIC HYDROCARBONS AND SOVATION ENERGIES OF THEIR ANIONS

    EPA Science Inventory

    Electron affinities (EAs) and free energies for electron attachment have been calculated for 42 polynuclear aromatic hydrocarbons and related molecules by a variety of theoretical models, including Koopmans' theorem methods and the L1E method from differences in energy between th...

  6. Particle in a Disk: A Spectroscopic and Computational Laboratory Exercise Studying the Polycyclic Aromatic Hydrocarbon Corannulene

    ERIC Educational Resources Information Center

    Frey, E. Ramsey; Sygula, Andrzej; Hammer, Nathan I.

    2014-01-01

    This laboratory exercise introduces undergraduate chemistry majors to the spectroscopic and theoretical study of the polycyclic aromatic hydrocarbon (PAH), corannulene. Students explore the spectroscopic properties of corannulene using UV-vis and Raman vibrational spectroscopies. They compare their experimental results to simulated vibrational…

  7. SELECTIVE ENUMERATION OF AROMATIC AND ALIPHATIC HYDROCARBON DEGRADING BACTERIA BY A MOST-PROBABLE-NUMBER PROCEDURE

    EPA Science Inventory

    A most-portable-number (MPN) procedure was developed to separately enumerate aliphatic and aromatic hydrocarbon degrading bacteria, because most of the currently available methods are unable to distinguish between these two groups. Separate 96-well microtiter plates are used to ...

  8. 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...

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

    SciTech Connect

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

    1996-09-01

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

  10. 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 ...

  11. Immunological disorders associated with polychlorinated biphenyls and related halogenated aromatic hydrocarbon compounds

    USGS Publications Warehouse

    Noguchi, G.E.

    1998-01-01

    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.

  12. 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....

  13. ANALYSIS OF POLYCYCLIC AROMATIC HYDROCARBONS BY ION TRAP TANDEM MASS SPECTROMETRY

    EPA Science Inventory

    An ion-trap mass spectrometer with a wave board and tandem mass spectrometry software was used to analyze gas chromatographically separated polycyclic aromatic hydrocarbons (PAHs) by using collision-induced dissociation (CID). The nonresonant (multiple collision) mode was used to...

  14. 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...

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

    SciTech Connect

    Peron, O.; Rinnert, E.; Compere, C.; Toury, T.; Lamy de la Chapelle, M.

    2010-08-06

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

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

    USGS Publications Warehouse

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

    1995-01-01

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

  17. PERSONAL EXPOSURE TO FINE PARTICLE POLYCYCLIC AROMATIC HYDROCARBONS: OUTDOOR SOURCE TRACERS

    EPA Science Inventory


    The most carcinogenic and toxic polycyclic aromatic hydrocarbons (PAH) are the 4-5 ring PAH found preferentially adsorbed to the fine particles (<2.54u in urban ambient air and personal air. Personal exposure to the carcinogenic particle bound PAH is also highly correlated ...

  18. 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 ...

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

    PubMed

    Oberoi, Akashdeep Singh; Philip, Ligy; Bhallamudi, S Murty

    2015-08-01

    Present study focused on the screening of bacterial consortium for biodegradation of monocyclic aromatic hydrocarbon (MAH) and polycyclic aromatic hydrocarbons (PAHs). Target compounds in the present study were naphthalene, acenaphthene, phenanthrene (PAHs), and benzene (MAH). Microbial consortia enriched with the above target compounds were used in screening experiments. Naphthalene-enriched consortium was found to be the most efficient consortium, based on its substrate degradation rate and its ability to degrade other aromatic pollutants with significantly high efficiency. Substrate degradation rate with naphthalene-enriched culture followed the order benzene > naphthalene > acenaphthene > phenanthrene. Chryseobacterium and Rhodobacter were discerned as the predominant species in naphthalene-enriched culture. They are closely associated to the type strain Chryseobacterium arthrosphaerae and Rhodobacter maris, respectively. Single substrate biodegradation studies with naphthalene (PAH) and benzene (MAH) were carried out using naphthalene-enriched microbial consortium (NAPH). Phenol and 2-hydroxybenzaldehyde were identified as the predominant intermediates during benzene and naphthalene degradation, respectively. Biodegradation of toluene, ethyl benzene, xylene, phenol, and indole by NAPH was also investigated. Monod inhibition model was able to simulate biodegradation kinetics for benzene, whereas multiple substrate biodegradation model was able to simulate biodegradation kinetics for naphthalene. PMID:26054614

  20. Dermal exposure to jet fuel suppresses delayed-type hypersensitivity: a critical role for aromatic hydrocarbons.

    PubMed

    Ramos, Gerardo; Limon-Flores, Alberto Yairh; Ullrich, Stephen E

    2007-12-01

    Dermal exposure to military (JP-8) and/or commercial (Jet-A) jet fuel suppresses cell-mediated immune reactions. Immune regulatory cytokines and biological modifiers, including platelet activating factor (PAF), prostaglandin E(2), and interleukin-10, have been implicated in the pathway of events leading to immune suppression. It is estimated that approximately 260 different hydrocarbons are found in jet fuel, and the exact identity of the active immunotoxic agent(s) is unknown. The recent availability of synthetic jet fuel (S-8), which is refined from natural gas, and is devoid of aromatic hydrocarbons, made it feasible to design experiments to address this problem. Here we tested the hypothesis that the aromatic hydrocarbons present in jet fuel are responsible for immune suppression. We report that applying S-8 to the skin of mice does not upregulate the expression of epidermal cyclooxygenase-2 (COX-2) nor does it induce immune suppression. Adding back a cocktail of seven of the most prevalent aromatic hydrocarbons found in jet fuel (benzene, toluene, ethylbenzene, xylene, 1,2,4-trimethlybenzene, cyclohexylbenzene, and dimethylnaphthalene) to S-8 upregulated epidermal COX-2 expression and suppressed a delayed-type hypersensitivity (DTH) reaction. Injecting PAF receptor antagonists, or a selective cycloozygenase-2 inhibitor into mice treated with S-8 supplemented with the aromatic cocktail, blocked suppression of DTH, similar to data previously reported using JP-8. These findings identify the aromatic hydrocarbons found in jet fuel as the agents responsible for suppressing DTH, in part by the upregulation of COX-2, and the production of immune regulatory factors and cytokines. PMID:17890764

  1. Effect of three aromatic hydrocarbons on respiration and heart rates of the mussel, mytilus californianus

    SciTech Connect

    Sabourin, T.D.; Tullis, R.E.

    1981-06-01

    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.

  2. Simulated non-contact atomic force microscopy for polycyclic aromatic hydrocarbons

    NASA Astrophysics Data System (ADS)

    Chelikowsky, James; Kim, Minjung

    2014-03-01

    Theoretical simulations of non-contact atomic force microscopy (AFM) play an important role in analyzing measured images. Recent non-contact AFM studies on polycyclic aromatic hydrocarbons have achieved atomic resolution that is not observed in other imaging techniques such as scanning tunneling microscopy. In particular, AFM images for these hydrocarbons have resolved bond orders of individual carbon-carbon bonds. Here we present simulated AFM images for several polycyclic aromatic hydrocarbons and explain the role of molecular functionalized AFM tips. Our work is based on solving the electronic structure problem using real space pseudopotentials constructed within density functional theory. Our work is supported by the DOE under DOE/DE-FG02-06ER46286. Computational resources were provided by NERSC and XSEDE.

  3. 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...

  4. Aromatic hydrocarbons associated with brines from geopressured wells

    SciTech Connect

    Not Available

    1992-09-01

    The various operational wells were sampled on a monthly basis for the yield of the cryocondensate hydrocarbons. The total cryocondensate concentration as well as the concentrations in the brine and the gas after passing the separator system are summarized. The total cryocondensate yield is displayed.

  5. 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 310380 nm ultraviolet light. Triethylamine was utilized for extraction of PAH compounds from motor oil...

  6. Mutagenic and carcinogenic significance and the possible induction of lung cancer by nitro aromatic hydrocarbons in particulate pollutants.

    PubMed Central

    Tokiwa, H; Sera, N; Nakashima, A; Nakashima, K; Nakanishi, Y; Shigematu, N

    1994-01-01

    Studies of genotoxicity and carcinogenicity of nitro aromatic hydrocarbons focus on their high mutagenicity for bacteria and mammalian cells. Nitrobenzo[a]pyrenes (NBPs) and related nitroazaarenes also are extraordinarily mutagenic. 3-Nitro-6-azabenzo[a]pyren-N-oxide was found to be a more potent mutagen than 1,8-dinitropyrene. Mutagenicity of NBPs was associated with the position of substitution of the nitro function when nitrogen dioxide (NO2) was substituted at the third position on the benzo[a]pyrene (BP) structure, as in 3,6-dinitrobenzo[a]pyrene but not in 1,6-diNBP. The NBPs were reduced by a rat liver postmitochondrial fraction to nitroso- and subsequently to amino-derivatives. Therefore, tumoral action in rats was induced at significant levels by subcutaneous injection of 3,6-diNBP, but no tumors were observed in rats given 1,6-diNBP. Carcinogenic nitropyrenes were detected in the resected lung of a patient with lung cancer. It is suggested that the presence of nitropyrenes and the resulting tumor were due to exposure to by-products of combustion of heavy oil. The patient was a nonsmoker and farmer who had bred chickens for 40 years. He used heavy oil for heating the chicken house. Similarly, a group of Chinese people at high risk of developing lung cancer was selected to determine the initiator of lung cancer. Lung cancers were obtained from six Chinese female nonsmokers who were living in Fuyuan County, China. Polycyclic aromatic hydrocarbons were detected in resected lung specimens; they were benzo[k]fluoranthene, BP, benzo[g,h,i]perylene, and pyrene. These cases were associated with exposure to soot from combustion of coal usually used for heating and cooking indoors. PMID:7821284

  7. Air pollution in southern California museums: Indoor and outdoor levels of nitrogen dioxide, peroxyacetyl nitrate, nitric acid, and chlorinated hydrocarbons

    SciTech Connect

    Hisham, M.W.M.; Grosjean, D. )

    1991-05-01

    A survey of the air pollutants nitrogen dioxide, peroxyacetyl nitrate, methylchloroform, tetrachlorethylene, and nitric acid has been carried out at nine Southern California museums. Highest indoor levels were 120 ppb for NO{sub 2} 14 ppb for PAN, 10 ppb for nitric acid, and more than 12 and 30 ppb for Cl{sub 2}C{double bond}CCl{sub 2} and CH{sub 3}CCl{sub 3}, respectively. At all but one museum, indoor concentrations of NO{sub 2}, PAN, and nitric acid were comparable to outdoor levels and closely followed outdoor air exchange. At six of the nine institutions surveyed, indoor levels of chlorinated hydrocarbons were higher than outdoor concentrations, thus pointing to indoor sources. At museums lacking air conditioning (HVAC) systems, indoor levels of air pollutants were essentially identical with outdoor ones. At institutions with HVAC, levels of NO{sub 2}, PAN, chlorinated hydrocarbons, and the corresponding indoor/outdoor ratios were high and indicated only modest removal by the HVAC system. Of the three museums equipped with HVAC and chemical filtration, only one yielded low indoor pollutant concentrations and low indoor/outdoor ratios.

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

    PubMed

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

    2016-01-01

    We have analyzed a set of 51 PAHs whose structures have been hypothesized from mass spectrometry data collected on samples extracted from carbon particles of combustion origin. We have obtained relationships between infrared absorption signals in the fingerprint region (mid-IR) and the chemical structures of PAHs, thus proving the potential of IR spectroscopy for the characterization of the molecular structure of aromatic combustion products. The results obtained here for the spectroscopic characterization of PAHs can be also of interest in Materials Science and Astrophysics. PMID:26208268

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

    NASA Astrophysics Data System (ADS)

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

    2016-01-01

    We have analyzed a set of 51 PAHs whose structures have been hypothesized from mass spectrometry data collected on samples extracted from carbon particles of combustion origin. We have obtained relationships between infrared absorption signals in the fingerprint region (mid-IR) and the chemical structures of PAHs, thus proving the potential of IR spectroscopy for the characterization of the molecular structure of aromatic combustion products. The results obtained here for the spectroscopic characterization of PAHs can be also of interest in Materials Science and Astrophysics.

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

    PubMed

    Tarnow, Patrick; Hutzler, Christoph; Grabiger, Stefan; Schön, Karsten; Tralau, Tewes; Luch, Andreas

    2016-01-01

    The majority of printing inks are based on mineral oils (MOs) which contain complex mixtures of saturated and aromatic hydrocarbons. Consumer exposure to these oils occurs either through direct skin contacts or, more frequently, as a result of MO migration into the contents of food packaging that was made from recycled newspaper. Despite this ubiquitous and frequent exposure little is known about the potential toxicological effects, particularly with regard to the aromatic MO fractions. From a toxicological point of view the huge amount of alkylated and unsubstituted compounds therein is reason for concern as they can harbor genotoxicants as well as potential endocrine disruptors. The aim of this study was to assess both the genotoxic and estrogenic potential of MOs used in printing inks. Mineral oils with various aromatic hydrocarbon contents were tested using a battery of in vitro assays selected to address various endpoints such as estrogen-dependent cell proliferation, activation of estrogen receptor α or transcriptional induction of estrogenic target genes. In addition, the comet assay has been applied to test for genotoxicity. Out of 15 MOs tested, 10 were found to potentially act as xenoestrogens. For most of the oils the effects were clearly triggered by constituents of the aromatic hydrocarbon fraction. From 5 oils tested in the comet assay, 2 showed slight genotoxicity. Altogether it appears that MOs used in printing inks are potential endocrine disruptors and should thus be assessed carefully to what extent they might contribute to the total estrogenic burden in humans. PMID:26771904

  11. Microbial metabolism of polycyclic aromatic hydrocarbons: isolation and characterization of a pyrene-degrading bacterium.

    PubMed Central

    Heitkamp, M A; Franklin, W; Cerniglia, C E

    1988-01-01

    Microbiological analyses of sediments located near a point source for petrogenic chemicals resulted in the isolation of a pyrene-mineralizing bacterium. This isolate was identified as a Mycobacterium sp. on the basis of its cellular and colony morphology, gram-positive and strong acid-fast reactions, diagnostic biochemical tests, 66.6% G + C content of the DNA, and high-molecular-weight mycolic acids (C58 to C64). The mycobacterium mineralized pyrene when grown in a mineral salts medium supplemented with nutrients but was unable to utilize pyrene as a sole source of carbon and energy. The mycobacterium grew well at 24 and 30 degrees C and minimally at 35 degrees C. No growth was observed at 5 or 42 degrees C. The mycobacterium grew well at salt concentrations up to 4%. Pyrene-induced Mycobacterium cultures mineralized 5% of the pyrene after 6 h and reached a maximum of 48% mineralization within 72 h. Treatment of induced and noninduced cultures with chloramphenicol showed that pyrene-degrading enzymes were inducible in this Mycobacterium sp. This bacterium could also mineralize other polycyclic aromatic hydrocarbons and alkyl- and nitro-substituted polycyclic aromatic hydrocarbons including naphthalene, phenanthrene, fluoranthene, 3-methylcholanthrene, 1-nitropyrene, and 6-nitrochrysene. This is the first report of a bacterium able to extensively mineralize pyrene and other polycyclic aromatic hydrocarbons containing four aromatic rings. Images PMID:3202633

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

    PubMed Central

    Tarnow, Patrick; Hutzler, Christoph; Grabiger, Stefan; Schön, Karsten; Tralau, Tewes; Luch, Andreas

    2016-01-01

    The majority of printing inks are based on mineral oils (MOs) which contain complex mixtures of saturated and aromatic hydrocarbons. Consumer exposure to these oils occurs either through direct skin contacts or, more frequently, as a result of MO migration into the contents of food packaging that was made from recycled newspaper. Despite this ubiquitous and frequent exposure little is known about the potential toxicological effects, particularly with regard to the aromatic MO fractions. From a toxicological point of view the huge amount of alkylated and unsubstituted compounds therein is reason for concern as they can harbor genotoxicants as well as potential endocrine disruptors. The aim of this study was to assess both the genotoxic and estrogenic potential of MOs used in printing inks. Mineral oils with various aromatic hydrocarbon contents were tested using a battery of in vitro assays selected to address various endpoints such as estrogen-dependent cell proliferation, activation of estrogen receptor α or transcriptional induction of estrogenic target genes. In addition, the comet assay has been applied to test for genotoxicity. Out of 15 MOs tested, 10 were found to potentially act as xenoestrogens. For most of the oils the effects were clearly triggered by constituents of the aromatic hydrocarbon fraction. From 5 oils tested in the comet assay, 2 showed slight genotoxicity. Altogether it appears that MOs used in printing inks are potential endocrine disruptors and should thus be assessed carefully to what extent they might contribute to the total estrogenic burden in humans. PMID:26771904

  13. Polycyclic aromatic hydrocarbons physically intercalate into duplex regions of denatured DNA

    SciTech Connect

    Wolfe, A.; Shimer, G.H. Jr.; Meehan, T.

    1987-10-06

    The authors have investigated the physical binding of pyrene and benzo(a)pyrene derivatives to denatured DNA. These compounds exhibit a red shift in their absorbance spectra of 9 nm when bound to denatured calf thymus DNA, compared to a shift of 10 nm when binding occurs to native DNA. Fluorescence from the hydrocarbons is severely quenched when bound to both native and denatured DNA. Increasing sodium ion concentration decreases binding of neutral polycyclic aromatic hydrocarbons to native DNA and increases binding to denatured DNA. The direct relationship between binding to denatured DNA and salt concentration appears to be a general property of neutral polycyclic aromatic hydrocarbons. Absorption measurements at 260 nm were used to determine the duplex content of denatured DNA. When calculated on the basis of duplex binding sites, equilibrium constants for binding of 7,8,9,10-tetrahydroxy-7,8,9,10-tetrahydrobenzo(a)pyrene to denatured DNA are an order of magnitude larger than for binding to native DNA. The effect of salt on the binding constant was used to calculate the sodium ion release per bound ligand, which was 0.36 for both native and denatured DNA. Increasing salt concentration increases the duplex content of denatured DNA, and it appears that physical binding of polycyclic aromatic hydrocarbons consists of intercalation into these sites.

  14. Aromatic hydrocarbons associated with brines from geopressured wells

    SciTech Connect

    Keeley, D.F.; Meriwether, J.R.

    1991-01-01

    The measurement of the basic physical chemical properties of the components of brine produced in the US DOE geopressured wells is necessary to provide the fundamental data necessary for understanding the mechanisms by which constituents of petroleum migrate and are partitioned into different phases in various geologic strata. The cryocondensate materials, which we sample, are present in the geopressured brines of all the wells observed to date. These materials are a complex mixture of aromatic compounds ranging in complexity from benzene to highly substituted anthracenes. While data is available for room temperature and for solutions of pure water, there is little earlier information on these compounds in solutions of higher salinity and at elevated temperatures. Our work extended the basic solubility data for benzene and toluene (two of the major aromatic constituents of the geopressured brine) to higher sodium chloride concentrations. The techniques we have developed during the course of this work allows us to make solubility measurements with precision and to make major contributions to the basic literature. It is important to realize that reliable data on these fundamental quantities comes only with great attention to detail and an insistence on consistency and reproducibility. To determine the solubility of one compound at one set of conditions requires the manual injection of a minimum of 45 samples into a gas chromatograph and an analysis of each chromatogram. 10 figs., 10 tabs.

  15. Public health impacts of secondary particulate formation from aromatic hydrocarbons in gasoline

    PubMed Central

    2013-01-01

    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 with exposures to the subset of PM2.5 that originates from vehicle emissions of aromatics under business as usual conditions. Methods The PM2.5 contribution from gasoline aromatics is estimated using the Community Multiscale Air Quality (CMAQ) modeling system and the results are compared to ambient measurements from the literature. Marginal PM2.5 annualized concentration changes are used to calculate premature mortalities using concentration-response functions, with a value of mortality reduction approach used to monetize the social cost of mortality impacts. Morbidity impacts are qualitatively discussed. Results Modeled aromatic SOA concentrations from CMAQ fall short of ambient measurements by approximately a factor of two nationwide, with strong regional differences. After accounting for this model bias, the estimated public health impacts from exposure to PM2.5 originating from aromatic hydrocarbons in gasoline lead to a central estimate of approximately 3800 predicted premature mortalities nationwide, with estimates ranging from 1800 to over 4700 depending on the specific concentration-response function used. These impacts are associated with total social costs of $28.2B, and range from $13.6B to $34.9B in 2006$. Conclusions These preliminary quantitative estimates indicate particulates from vehicular emissions of aromatic hydrocarbons demonstrate a nontrivial public health burden. The results provide a baseline from which to evaluate potential public health impacts of changes in gasoline composition. PMID:23425393

  16. A comparison of the biodegradation of aromatic hydrocarbons in three different systems

    SciTech Connect

    Kagi, R.I.; Fisher, S.J.; Alexander, R.

    1996-10-01

    In three case studies, the circumstances in which petroleum hydrocarbon biodegradation took place were markedly different. (1) Two reservoir-biodegraded oils from the Barrow Sub-basin. (2) Petroleum hydrocarbons from a condensate which had seeped into a mangrove creek bed. (3) Hydrocarbons in sediments exposed to drilling discharges from an off-shore petroleum platform. For each case, the progress of biodegradation of the aromatic hydrocarbons was studied in detail using GC-MS and GC-FTIR, so that the susceptibility to biodegradation of individual methylated naphthalenes and alkylphenanthrenes could be established. Striking similarities were observed in the progress of biodegradation in the three different environments, especially with the alkylnaphthalenes. One particularly prominent feature of all three systems was that 1,6 dimethyl substituted naphthalenes are more susceptible than other isomers. These similarities raise interesting questions about the mechanisms of biodegradation in these three systems.

  17. Phase and size distributions of polycyclic aromatic hydrocarbons in environmental tobacco smoke

    SciTech Connect

    Gundel, L.A.; Daisey, J.M.; Hering, S.V.

    1995-12-31

    Phase and size distributions of polycyclic aromatic hydrocarbons (PAH) influence lung dosimetry for environmental tobacco smoke (ETS). Gas-phase components of ETS, especially water-soluble species, deposit more efficiently than particles, but they deposit in the upper airways of the human respiratory system where they can be cleared quickly. Typical ETS particles of 0.1 to 0.5 {mu}m diameter are not deposited as efficiently as gases, but they penetrate deeply into the lung and are cleared more slowly than water-soluble gas-phase components. Although the dosimetry of organic compounds in the particulate phase depends on their particle-size distribution, very little data is available for specific chemical classes such as PAH in ETS. Even less is known about the dynamic behavior of the size distribution of PAH in ETS as the smoke is diluted and aged in indoor environments. Previous studies suggest that evaporation of compounds with high volatility will dry out sidestream cigarette smoke as it is diluted into a room, and this effect will decrease the PAH concentration in smaller particles more than the bigger particles. Larger particles may also accumulate PAH by condensation of species with higher boiling points. Two new tools have been developed recently to measure the phase and size distributions of PAH, and they have been used here to investigate the dynamic behavior of simulated ETS at two temperatures (18.3 and 25.1 {degrees}C). Phase distributions of PAH have been measured in simulated ETS (diluted sidestream smoke) using the new annular denuder-based Integrated Organic Vapor-Particle sampler (IOVPS). Simultaneously, the size distributions of particulate PAH have been determined with a new microslot impactor, the Size-Segregated Environmental Tobacco Smoke Sampler (SSETS) that has cutpoints at 0.10, 0.38, 0.48, 1.7 and 3.5 {mu}m. The IOVPS and SSETS operated in an environmental chamber (20 m{sup 3}) to sample PAH over two 45-min intervals.

  18. Blockade of the aryl hydrocarbon receptor pathway triggered by dioxin, polycyclic aromatic hydrocarbons and cigarette smoke by Phellinus linteus.

    PubMed

    Mukai, Mai; Kasai, Ayumi; Hiramatsu, Nobuhiko; Hayakawa, Kunihiro; Okamura, Maro; Tagawa, Yasuhiro; Yao, Jian; Nakamura, Tomoyuki; Kitamura, Masanori

    2008-10-01

    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

  19. Polycyclic aromatic hydrocarbon degradation of phytoplankton-associated Arenibacter spp. and description of Arenibacter algicola sp. nov., an aromatic hydrocarbon-degrading bacterium.

    PubMed

    Gutierrez, Tony; Rhodes, Glenn; Mishamandani, Sara; Berry, David; Whitman, William B; Nichols, Peter D; Semple, Kirk T; Aitken, Michael D

    2014-01-01

    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 TG409(T)) exhibited >99% sequence identity to three type strains of this genus. On the basis of phenotypic and genotypic characteristics, strain TG409(T) 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 TG409(T) 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. PMID:24212584

  20. Polycyclic Aromatic Hydrocarbon Degradation of Phytoplankton-Associated Arenibacter spp. and Description of Arenibacter algicola sp. nov., an Aromatic Hydrocarbon-Degrading Bacterium

    PubMed Central

    Rhodes, Glenn; Mishamandani, Sara; Berry, David; Whitman, William B.; Nichols, Peter D.; Semple, Kirk T.; Aitken, Michael D.

    2014-01-01

    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. PMID:24212584

  1. Origin of Organic Globules in Meteorites: Laboratory Simulation Using Aromatic Hydrocarbons

    NASA Astrophysics Data System (ADS)

    Saito, Midori; Kimura, Yuki

    2009-10-01

    Analogs of organic hollow globules, which have been found in carbonaceous chondrite meteorites and interplanetary dust particles, were synthesized in our laboratory from benzene and anthracene using plasma. Our results suggest that organic globules could be made from aromatic rings in circumstellar envelopes around evolved stars. The hollow interior could be formed by coagulation of vacancies, formed by electronic excitation and/or knock-out of carbon atoms following irradiation by plasma particles such as protons and He+ ions. This experimental result suggests that organic globules are possibly the final products in the evolution of carbonaceous matter from acetylene and benzene to polycyclic aromatic hydrocarbons in ejecta gas from evolved stars.

  2. Investigation of aromatic hydrocarbons as impurities in dimethyl formamide and their luminescene determination

    SciTech Connect

    Kozlova, G.G.; Botin'eva, A.M.; Vasilevskaya, L.N.

    1986-09-01

    The authors considered the presence of aromatic hydrocarbons with condensed rings as impurities of dimethyl formanide (DMF). This paper studies the structures of impurities and the possibility of their determination using luminescence methods. Luminescence spectra of impurities in DMF and model systems were taken in benzene and in pruified DMF. It is shown that high-boiling substances (aromatic compounds with alkylbenzene, naphthalene, and anthracene groups) are impurities in DMF. Their functional group composition has been studied and a luminescence procedure for fast routine identification of naphthalene and anthracene in DMF as well as a procedure of naphthalene determination in DMF are proposed.

  3. Atmospheric chemistry of gas-phase polycyclic aromatic hydrocarbons: formation of atmospheric mutagens.

    PubMed Central

    Atkinson, R; Arey, J

    1994-01-01

    The atmospheric chemistry of the 2- to 4-ring polycyclic aromatic hydrocarbons (PAH), which exist mainly in the gas phase in the atmosphere, is discussed. The dominant loss process for the gas-phase PAH is by reaction with the hydroxyl radical, resulting in calculated lifetimes in the atmosphere of generally less than one day. The hydroxyl (OH) radical-initiated reactions and nitrate (NO3) radical-initiated reactions often lead to the formation of mutagenic nitro-PAH and other nitropolycyclic aromatic compounds, including nitrodibenzopyranones. These atmospheric reactions have a significant effect on ambient mutagenic activity, indicating that health risk assessments of combustion emissions should include atmospheric transformation products. PMID:7821285

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

    PubMed

    Mostafa, Gamal A

    2002-03-01

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

  5. Aromatic hydrocarbons associated with brines from geopressured wells

    SciTech Connect

    Keeley, D.F.; Meriwether, J.R.

    1989-01-01

    The measurement of basic physical chemical properties of the brine components produced in the US DOE geopressured wells it necessary to provide the fundamental data necessary for an understanding of the mechanisms by which constituents of petroleum migrate and are partitioned into different phases in various geologic strata. The cryocondensate materials, which we sample, are present in the geopressured brines of all the wells observed to date. These materials are a complex mixture of aromatic compounds ranging in complexity from benzene to alkyl substituted anthracenes. This progress report includes articles published in the open literature from the data and findings of this project. Topics include the solubility and thermodynamic distribution coefficients. To accomplish these measurements of solubility and distribution coefficients, new techniques and new equipment were developed and were also published as journal articles.

  6. Polycyclic aromatic hydrocarbon formation in carbon-rich stellar envelopes

    NASA Technical Reports Server (NTRS)

    Cherchneff, Isabelle; Barker, John R.; Tielens, Alexander G. G. M.

    1992-01-01

    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.

  7. Biogeochemistry of aromatic and saturated hydrocarbons in a rocky intertidal marine community in the Strait of Juan de Fuca

    SciTech Connect

    Clark, R.C. Jr.

    1983-01-01

    Seasonal distributions of aromatic and saturated hydrocarbons were determined in important members of a rocky intertidal marine community remote from known sources of petroleum input. Nine major species were sampled quarterly for four years at Freshwater Bay, west of Port Angeles on the Strait of Juan de Fuca. More than seventy physical and chemical parameters were obtained for use in evaluating seasonal, annual, and interspecies trends. A simplified food chain study using /sup 3/H-naphthalane added to a seawater-phytoplankton-herbivore-carnivore system demonstrated the transfer of an aromatic petroleum-type hydrocarbon from seawater to organisms typically found in a stable rocky intertidal community. The phytoplankton and herbivore showed a biomagnification of /sup 3/H-naphthalene in the food chain, but the carnivore did not, possibly due to metabolism of the labelled aromatic hydrocarbon and subsequent discharge of water-soluble radioactive products. These studies suggest that aromatic hydrocarbons may be good indicators of short-term petroleum contamination only in species without enzymatic detoxification pathways. Saturated hydrocarbons tend to be better longer-term indicators. Saturated hydrocarbons do not show statistically significant seasonal variations. While organisms displayed some seasonal variations in aromatic hydrocarbons, no universally consistent relationship between seasonal patterns in different organisms was observed. When exposed to spilled oil, organisms similar to Freshwater Bay populations took up different amounts of petroleum hydrocarbons according to type of oil, spill location, duration, and intensity of exposure.

  8. Air monitoring of aromatic hydrocarbons during automobile spray painting for developing change schedule of respirator cartridges

    PubMed Central

    2014-01-01

    In the absence of End of Service Life Indicator (ESLI), a cartridge change schedule should be established for ensuring that cartridges are changed before their end of service life. Factors effecting service life of cartridges were evaluated, including the amount of atmospheric contamination with aromatic hydrocarbon vapors in the workplace, temperature, and relative humidity of the air. A new change schedule was established based on comparing the results of air monitoring and workplace conditions, laboratory experiment, and the NIOSH MultiVapor software. Spray painters were being exposed to aromatic hydrocarbons in a range exceeding occupational exposure limits. The cartridge change schedule was not effective and could no longer provide adequate protection against organic contaminants for sprayers. Change schedules for respirator cartridges should be reduced from 16–24 hours to 4 hours. NIOSH’s service life software program could be applied to developing cartridge change schedules. PMID:24468234

  9. Validation of an in vitro normal rainbow trout hepatocyte bioassay for halogenated aromatic hydrocarbons

    SciTech Connect

    Hayden, J.; Goudey, J.S.; Balch, G.

    1995-12-31

    The validity of in vitro cell culture models for the measurement of halogenated aromatic hydrocarbons (HAH) toxicity or the prediction of potential toxicity depends upon the ability of the mode reflect in vivo toxicity. HAH toxicity is directly related to the affinity for the aromatic hydrocarbon receptor (AhR) which controls cytochrome P45 activity. In the bioassay characterized, normal rainbow trout hepatocyte monolayer cultures (RTL-WI) are employed to measure the modulation of cytochrome P450 monooxygenase activity, using the ethoxyresorufin-O-deethylase (EROD) assay, following the exposure to betanaphthaflavone (BNF) and environmental samples for varying times. Data from this single plate hepatocyte study are compared with liver microsomal EROD activity from rainbow trout exposed to the same samples in vivo.

  10. Air monitoring of aromatic hydrocarbons during automobile spray painting for developing change schedule of respirator cartridges.

    PubMed

    Jahangiri, Mehdi; Adl, Javad; Shahtaheri, Seyed Jamaleddin; Kakooe, Hossein; Rahimi Forushani, Abbas; Ganjali, Mohammad Reza

    2014-01-01

    In the absence of End of Service Life Indicator (ESLI), a cartridge change schedule should be established for ensuring that cartridges are changed before their end of service life. Factors effecting service life of cartridges were evaluated, including the amount of atmospheric contamination with aromatic hydrocarbon vapors in the workplace, temperature, and relative humidity of the air. A new change schedule was established based on comparing the results of air monitoring and workplace conditions, laboratory experiment, and the NIOSH MultiVapor software. Spray painters were being exposed to aromatic hydrocarbons in a range exceeding occupational exposure limits. The cartridge change schedule was not effective and could no longer provide adequate protection against organic contaminants for sprayers. Change schedules for respirator cartridges should be reduced from 16-24 hours to 4 hours. NIOSH's service life software program could be applied to developing cartridge change schedules. PMID:24468234

  11. Study of Graphene Formed in the Atmosphere of Vapors of Aromatic Hydrocarbons

    NASA Astrophysics Data System (ADS)

    Baitimbetova, B. A.; Vermenichev, B. M.; Ryabikin, Yu. A.; Mansurov, Z. A.; Abdikasova, A. A.

    2015-07-01

    For the first time graphene structures are obtained by reactive magnetron sputtering with the graphite cathode in vapors of one of the representatives of the wide class of aromatic hydrocarbons - naphthalene. The carbon grid of the molecular structure of aromatic hydrocarbons coincides with the graphene of the carbon grid. The paper presents the technique of obtaining graphene and results of investigations of its structural peculiarities by methods of Raman light scattering spectroscopy, electron paramagnetic resonance, and atomic force microscopy. Graphene peaks with the vibrational mode (2D-zone) at a frequency of ~2728 cm-1 are identified by the method of Raman spectroscopy. Results of investigations by the method of atomic force microscopy confirm the formation of graphene sheets and carbon nanotubes. Results of investigations are presented and discussed.

  12. Renal cancer risk and occupational exposure to polycyclic aromatic hydrocarbons and plastics

    PubMed Central

    Karami, Sara; Boffetta, Paolo; Brennan, Paul; Stewart, Patricia A.; Zaridze, David; Matveev, Vsevolod; Janout, Vladimir; Kollarova, Helena; Bencko, Vladimir; Navratilova, Marie; Szeszenia-Dabrowska, Neonila; Mates, Dana; Gromiec, Jan P.; Sobotka, Roman; Chow, Wong-Ho; Rothman, Nathaniel; Moore, Lee E.

    2011-01-01

    Objective To investigate whether occupational exposure to polycyclic aromatic hydrocarbons and certain plastic monomers increased renal cell carcinomas (RCC) risk. Methods Unconditional logistic regression was used to calculate RCC risk in relation to exposure. Results No association between RCC risk and having ever been occupationally exposed to any polycyclic aromatic hydrocarbons or plastics was observed. Duration of exposure and average exposure also showed no association with risk. Suggestive positive associations between RCC risk and cumulative exposure to styrene (P-trend = 0.02) and acrylonitrile (P-trend = 0.06) were found. Cumulative exposure to petroleum/gasoline engine emissions was inversely associated with risk (P-trend = 0.02). Conclusions Results indicate a possible association between occupational styrene and acrylonitrile exposure and RCC risk. Additional studies are needed to replicate findings, as this is the first time these associations have been reported and they may be due to chance. PMID:21270648

  13. Characterization of subsurface polycyclic aromatic hydrocarbons at the Deepwater Horizon site

    NASA Astrophysics Data System (ADS)

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

    2010-10-01

    Here, we report the initial observations of distributions of polycyclic aromatic hydrocarbons (PAH) in subsurface waters near the Deepwater Horizon oil well site (also referred to as the Macondo, Mississippi Canyon Block 252 or MC252 well). Profiles of in situ fluorescence and beam attenuation conducted during 9-16 May 2010 were characterized by distinct peaks at depths greater than 1000 m, with highest intensities close to the wellhead and decreasing intensities with increasing distance from the wellhead. Gas chromatography/mass spectrometry (GC/MS) analyses of water samples coinciding with the deep fluorescence and beam attenuation anomalies confirmed the presence of polycyclic aromatic hydrocarbons (PAH) at concentrations reaching 189 ?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.

  14. Secondary Aerosol Formation from Oxidation of Aromatics Hydrocarbons by Cl atoms

    NASA Astrophysics Data System (ADS)

    Cai, X.; Griffin, R.

    2006-12-01

    Aerosol Formation From the Oxidation of Aromatic Hydrocarbons by Chlorine Atmospheric secondary organic aerosol (SOA) affects regional and global air quality. The formation mechanisms of SOA via the oxidation of volatile organic compounds by hydroxyl radicals, ozone, and nitrate radicals have been studied intensively during the last decade. Chlorine atoms (Cl) also have been hypothesized to be effective oxidants in marine and industrially influenced areas. Recent work by the authors has indicated that significant amounts of SOA are formed from the oxidation of monoterpenes by Cl. Aromatic hydrocarbons are important for generation of both SOA and ozone in urban areas because of their large emission rates and high reactivity. The goal of this work was to quantify the SOA formation potentials of two representative aromatic hydrocarbons through laboratory chamber experiments in which oxidation was initiated by Cl. The system constructed for this study includes an experimental chamber, a gas chromatograph for quantification of aromatic mixing ratios, a Scanning Mobility Particle Spectrometer to measure SOA size distributions, a zero air generator, and an illuminating system. The model aromatic hydrocarbons chosen for this study are toluene and m-xylene. Aerosol yields are estimated based on measured aerosol volume concentration, the concentration of consumed hydrocarbon, and estimation of wall loss of the newly formed aerosol. Toluene and m-xylene exhibit similar SOA yields from the oxidation initiated by Cl. The toluene SOA yield from Cl-initiated oxidation, however, depends on the ratio between the mixing ratios of the initial chlorine source and toluene in the chamber. For toluene experiments with higher such ratios, SOA yields vary from 0.05 to 0.079 for generated aerosol ranging from 4.2 to12.0 micrograms per cubic meter. In the lower ratio experiments, SOA yields are from 0.033 to 0.064, corresponding to generated aerosol from 3.0 to 11.0 micrograms per cubic meter. The m-xylene SOA yield ranges from 0.04 to 0.08 for aerosol in the range of 4.0 to 12.0 micrograms per cubic meter. These yields are generally comparable to those from photooxidation. In marine and industrial areas, SOA formation from the Cl- initiated oxidation of the studied common aromatics is likely to be most important in the early morning.

  15. 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...

  16. 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...

  17. 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...

  18. IMPORTANCE OF MATERNAL TRANSFER OF THE PHOTOREACTIVE POLYCYCLIC AROMATIC HYDROCARBON FLUORANTHENE FROM BENTHIC ADULT BIVALVES TO THEIR PELAGIC LARVAE

    EPA Science Inventory

    Laboratory experiments were conducted to determine if maternal transfer of polycyclic aromatic hydrocarbons (PAHs) from benthic adult bivalves could result in phototoxicity to their pelagic larvae when exposed to ultraviolet light (UV). In these experiments, adult bivalves were e...

  19. CROSS-INDUCTION OF PYRENE AND PHENANTHRENE IN MYCOBACTERIUM SP. ISOLATED FROM POLYCYCLIC AROMATIC HYDROCARBON CONTAMINATED RIVER SEDIMENTS

    EPA Science Inventory

    A polycyclic aromatic hydrocarbon (PAH)-degrading culture enriched from contaminated river sediments and a Mycobacterium sp. isolated from the enrichment were tested to investigate the possible synergistic and antagonistic interactions affecting the degradation of pyrene in the p...

  20. 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...

  1. Household air pollution and personal exposure risk of polycyclic aromatic hydrocarbons among rural residents in Shanxi, China.

    PubMed

    Chen, Y; Shen, G; Huang, Y; Zhang, Y; Han, Y; Wang, R; Shen, H; Su, S; Lin, N; Zhu, D; Pei, L; Zheng, X; Wu, J; Wang, X; Liu, W; Wong, M; Tao, S

    2016-04-01

    Polycyclic aromatic hydrocarbons (PAHs) are a group of pollutants of widespread concerns. Gaseous and size-segregated particulate-phase PAHs were collected in indoor and outdoor air in rural households. Personal exposure was measured and compared to the ingestion exposure. The average concentrations of 28 parent PAHs and benzo(a)pyrene (BaP) were 9000 ± 8390 and 131 ± 236 ng/m(3) for kitchen, 2590 ± 2270 and 43 ± 95 ng/m(3) for living room, and 2800 ± 3890 and 1.6 ± 0.7 ng/m(3) for outdoor air, respectively. The mass percent of high molecular weight (HMW) compounds with 5-6 rings contributed 1.3% to total 28 parent PAHs. Relatively higher fractions of HMW PAHs were found in indoor air compared to outdoor air. Majorities of particle-bound PAHs were found in the finest PM0.25 , and the highest levels of fine PM0.25 -bound PAHs were in the kitchen using peat and wood as energy sources. The 24-h personal PAH exposure concentration was 2100 ± 1300 ng/m(3) . Considering energies, exposures to those using wood were the highest. The PAH inhalation exposure comprised up to about 30% in total PAH exposure through food ingestion and inhalation, and the population attributable fraction (PAF) for lung cancer in the region was 0.85%. The risks for inhaled and ingested intakes of PAHs were 1.0 × 10(-5) and 1.1 × 10(-5) , respectively. PMID:25808453

  2. Synergism in the desorption of polycyclic aromatic hydrocarbons from soil models by mixed surfactant solutions.

    PubMed

    Sales, Pablo S; Fernández, Mariana A

    2016-05-01

    This study investigates the effect of a mixed surfactant system on the desorption of polycyclic aromatic hydrocarbons (PAHs) from soil model systems. The interaction of a non-ionic surfactant, Tween 80, and an anionic one, sodium laurate, forming mixed micelles, produces several beneficial effects, including reduction of adsorption onto solid of the non-ionic surfactant, decrease in the precipitation of the fatty acid salt, and synergism to solubilize PAHs from solids compared with individual surfactants. PMID:26873826

  3. Phototoxicity of non-carcinogenic polycyclic aromatic hydrocarbons in aquatic organisms

    SciTech Connect

    Kagan, J.; Kagan, E.D.; Kagan, I.A.; Kagan, P.A.; Quigley, S.

    1985-01-01

    Anthracene, fluoranthene, and pyrene are phototoxic in Daphnia magna, Artemia salina, first instar larvae of Aedes aegypti, late embryonic forms of Rana pipiens, and fish (Pimephales promelas). Since polycyclic aromatic hydrocarbons are generated in the combustion processes held responsible for the damages of acid rain, and they are introduced into the environment through other means as well, the high phototoxicity of the major pollutants, which are not carcinogenic, suggests that greater attention must be given to their environmental significance.

  4. Mass spectrometric study of secondary organic aerosol formed from the photo-oxidation of aromatic hydrocarbons

    NASA Astrophysics Data System (ADS)

    Sato, Kei; Takami, Akinori; Isozaki, Tasuku; Hikida, Toshihide; Shimono, Akio; Imamura, Takashi

    2010-03-01

    From measurements by an Aerodyne Aerosol Mass Spectrometer (AMS), secondary organic aerosol (SOA) formed in laboratory chambers is believed to be less oxidized than well-oxidized ambient organic aerosol (OA). However, the mass spectrum of SOA formed from the photo-oxidation of aromatic hydrocarbons has not been sufficiently studied by using AMS though these reactions are potential sources of urban SOA. In this study, we studied SOA formed from the photo-oxidation of seven aromatic hydrocarbons by using Time-of-Flight AMS. Strong mass signals from SOA were found at m/ z 43 (m43) and 44 (m44) in all the experiments. The m44 to total organic aerosol mass ratio (m44/OA) increased with irradiation time. For example, the m44/OA ratio increased from 10.6% to 13.3% during irradiation for 11 h in an experiment with toluene. The average m44/OA ratios were determined to be 5.8-17.1% for all the experiments. The m44/OA decreased and the m43/OA increased with increasing number of alkyl substituents of precursor aromatic hydrocarbons. This is because low-reactive ketones are preferentially produced rather than aldehydes with increasing number of alkyl substituents. The m44/OA ratios of the benzene and monoalkylbenzene oxidation were 12.2-17.1% and were close to those of well-oxidized ambient OA. These findings are consistent with the hypothesis that the photo-oxidation of aromatic hydrocarbons is a potential source of urban SOA. In addition to oxygenated organic compounds, organic nitrogen oxides were also shown to be present in SOA by high-resolution mass spectra.

  5. Complete genome of Martelella sp. AD-3, a moderately halophilic polycyclic aromatic hydrocarbons-degrading bacterium.

    PubMed

    Cui, Changzheng; Li, Zhijie; Qian, Jiangchao; Shi, Jie; Huang, Ling; Tang, Hongzhi; Chen, Xin; Lin, Kuangfei; Xu, Ping; Liu, Yongdi

    2016-05-10

    Martelella sp. strain AD-3, a moderate halophilic bacterium, was isolated from a petroleum-contaminated soil with high salinity in China. Here, we report the complete genome of strain AD-3, which contains one circular chromosome and two circular plasmids. An array of genes related to metabolism of polycyclic aromatic hydrocarbons and halophilic mechanism in this bacterium was identified by the whole genome analysis. PMID:26988395

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

    SciTech Connect

    Not Available

    1994-06-01

    The bibliography contains citations concerning the toxicity and biochemical effects of aromatic polycyclic hydrocarbons. Topics include effects on metabolism and liver activity, cellular responses, binding characteristics, and the occurrence and path of the compounds in food chains. Bioaccumulation studies in specific areas, and isolation and detection techniques are also considered. (Contains a minimum of 242 citations and includes a subject term index and title list.)

  7. Removal of polynuclear aromatic hydrocarbons from primary aluminum air pollution control scrubber wastewater

    SciTech Connect

    Dempsey, C.R.; Dostal, K.A.; Osantowski, R.A.

    1984-05-01

    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 the PAH's to 10 micrograms/l and evaluating the use of benzo(a)pyrene as an indicator for the removal of all PAH's.

  8. Average daily respiratory intake of polycyclic aromatic hydrocarbons in ambient air determined by capillary gas chromatography

    SciTech Connect

    Matsumoto, H.; Kashimoto, T.

    1985-01-01

    High-performance liquid chromatography (HPLC) is well used for the quantitative analysis of polycyclic aromatic hydrocarbons (PAH) in environmental samples with high sensitivity. However, it has a lower separation efficiency in comparison with capillary gas chromatography (GC). This paper describes the comparison of the GC method with the HPLC method by measuring the PAH in air particulate matter; and average daily respiratory intake (ADI) of them in ambient air by man is presented here.

  9. Degradation of Polycyclic Aromatic Hydrocarbons by a Newly Discovered Enteric Bacterium, Leclercia adecarboxylata

    PubMed Central

    Sarma, Priyangshu Manab; Bhattacharya, Dhruva; Krishnan, S.; Lal, Banwari

    2004-01-01

    A bacterial strain, PS4040, capable of degrading polycyclic aromatic hydrocarbons for use as the sole carbon source was isolated from oily-sludge-contaminated soil. The 16S rRNA gene showed 98.8% homology to that of Leclercia adecarboxylata. Comparative molecular typing with the clinical strain of L. adecarboxylata revealed that there were few comigrating and few distinct amplimers among them. PMID:15128584

  10. Degradation of polycyclic aromatic hydrocarbons by a newly discovered enteric bacterium, Leclercia adecarboxylata.

    PubMed

    Sarma, Priyangshu Manab; Bhattacharya, Dhruva; Krishnan, S; Lal, Banwari

    2004-05-01

    A bacterial strain, PS4040, capable of degrading polycyclic aromatic hydrocarbons for use as the sole carbon source was isolated from oily-sludge-contaminated soil. The 16S rRNA gene showed 98.8% homology to that of Leclercia adecarboxylata. Comparative molecular typing with the clinical strain of L. adecarboxylata revealed that there were few comigrating and few distinct amplimers among them. PMID:15128584

  11. A method of calculating the thermophysical parameters of liquid aromatic hydrocarbons

    SciTech Connect

    Mustafeev, R.A.; Gabulov, D.M.; Musaev, T.P.; Tagiev, S.I.

    1986-05-01

    Wide use is made of heat-transfer processes in advanced technology and in the chemical industry involving substances with largely unexamined thermophysical parameters. This paper proposes general formulas for the temperature dependence of the thermal conductivity, specific heat, density, surface tension, and latent heat of evaporation for certain aromatic hydrocarbons at atmospheric pressure. Results are presented for toluene, p-Xylene, m-Xylene, o-Xylene, ethylbenzene, and benzene.

  12. High mass carbon clusters from aromatic hydrocarbons observed by laser mass spectrometry

    SciTech Connect

    Lineman, D.N.; Somayajula, K.V.; Sharkey, A.G.; Hercules, D.M. )

    1989-06-29

    Laser time-of-flight mass spectra of polycyclic aromatic hydrocarbons showing positive ions, even-numbered carbon clusters to C{sub 584}{sup +} are reported. Negative ion spectra show clusters through C{sub 200}{sup {minus}}. Four different clustering regions are observed, depending upon laser focus conditions. Laser irradiance plays a key role. Greatly enhanced abundance of C{sub 60}{sup +} reported by others using graphite and other sources of carbon is not observed.

  13. Observational aspects of polycyclic aromatic hydrocarbon charging in the Interstellar Medium

    NASA Technical Reports Server (NTRS)

    Bakes, E. L. O.; Tielens, Alexander G. G. M.

    1995-01-01

    We have investigated the charging processes which affect small carbonaceous dust grains and polycyclic aromatic hydrocarbons (PAH's). Because of their high abundance, interstellar PAH molecules can dominate the charge balance of the interstellar medium (ISM), which controls the heating and cooling interstellar gas and interstellar chemistry. We present the results of our model, which compare well with observations and suggest further applications to both laboratory measurements and data obtainable from the KAO.

  14. Polycyclic Aromatic Hydrocarbon Metabolic Network in Mycobacterium vanbaaleniiPYR-1 ?

    PubMed Central

    Kweon, Ohgew; Kim, Seong-Jae; Holland, Ricky D.; Chen, Hongyan; Kim, Dae-Wi; Gao, Yuan; Yu, Li-Rong; Baek, Songjoon; Baek, Dong-Heon; Ahn, Hongsik; Cerniglia, Carl E.

    2011-01-01

    This study investigated a metabolic network (MN) from Mycobacterium vanbaaleniiPYR-1 for polycyclic aromatic hydrocarbons (PAHs) from the perspective of structure, behavior, and evolution, in which multilayer omics data are integrated. Initially, we utilized a high-throughput proteomic analysis to assess the protein expression response of M. vanbaaleniiPYR-1 to seven different aromatic compounds. A total of 3,431 proteins (57.38% of the genome-predicted proteins) were identified, which included 160 proteins that seemed to be involved in the degradation of aromatic hydrocarbons. Based on the proteomic data and the previous metabolic, biochemical, physiological, and genomic information, we reconstructed an experiment-based system-level PAH-MN. The structure of PAH-MN, with 183 metabolic compounds and 224 chemical reactions, has a typical scale-free nature. The behavior and evolution of the PAH-MN reveals a hierarchical modularity with funnel effects in structure/function and intimate association with evolutionary modules of the functional modules, which are the ring cleavage process (RCP), side chain process (SCP), and central aromatic process (CAP). The 189 commonly upregulated proteins in all aromatic hydrocarbon treatments provide insights into the global adaptation to facilitate the PAH metabolism. Taken together, the findings of our study provide the hierarchical viewpoint from genes/proteins/metabolites to the network via functional modules of the PAH-MN equipped with the engineering-driven approaches of modularization and rationalization, which may expand our understanding of the metabolic potential of M. vanbaaleniiPYR-1 for bioremediation applications. PMID:21725022

  15. Source identification of aromatic hydrocarbons in sediments using GC/MS

    SciTech Connect

    Sporstoel, S.; Gjos, N.; Lichtenthaler, R.G.; Gustavsen, K.O.; Urdal, K.; Oreld, F.; Skel, J.

    1983-01-01

    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 C/sub 1/-C/sub 3/ 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 components measured (relative amount of each aromatic series (RAA)) are graphically visualized. In combination these parameters give a first-order indication of the PAH source. Pyrene/fluoranthene AHD series appear to be especially sensitive as an indicator for detecting PAH from combustion sources. Interestingly the dibenzothiophene AHD series does not discriminate between crude oil and soot samples. The method is demonstrated on sediments from the North Sea and from Norwegian and Swedish fjords.

  16. Deuterium enrichment of polycyclic aromatic hydrocarbons by photochemically induced exchange with deuterium-rich cosmic ices

    NASA Technical Reports Server (NTRS)

    Sandford, S. A.; Bernstein, M. P.; Allamandola, L. J.; Gillette, J. S.; Zare, R. N.

    2000-01-01

    The polycyclic aromatic hydrocarbon (PAH) coronene (C24H12) frozen in D2O ice in a ratio of less than 1 part in 500 rapidly exchanges its hydrogen atoms with the deuterium in the ice at interstellar temperatures and pressures when exposed to ultraviolet radiation. Exchange occurs via three different chemical processes: D atom addition, D atom exchange at oxidized edge sites, and D atom exchange at aromatic edge sites. Observed exchange rates for coronene (C24H12)-D2O and d12-coronene (C24D12)-H2O isotopic substitution experiments show that PAHs in interstellar ices could easily attain the D/H levels observed in meteorites. These results may have important consequences for the abundance of deuterium observed in aromatic materials in the interstellar medium and in meteorites. These exchange mechanisms produce deuteration in characteristic molecular locations on the PAHs that may distinguish them from previously postulated processes for D enrichment of PAHs.

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

    PubMed

    Rončević, Srđan; Spasojević, Jelena; Maletić, Snežana; Jazić, Jelena Molnar; Isakovski, Marijana Kragulj; Agbaba, Jasmina; Grgić, Marko; Dalmacija, Božo

    2016-02-01

    Large amounts of sediment are dredged globally every year. This sediment is often contaminated with low concentrations of metals, polycyclic aromatic hydrocarbons, pesticides and other organic pollutants. Some of this sediment is disposed of on land, creating a need for risk assessment of the sediment disposal method, to minimize the degradation of environmental quality and prevent risks to human health. Evaluating the available fractions of certain polycyclic aromatic hydrocarbons is very important, as in the presence of various organisms, they are believed to be easily subject to the processes of bioaccumulation, biosorption and transformation. In order to determine the applicability of applying these methods for the evaluation of pollutant bioavailability in sediments, the desorption kinetics from the sediment of various polycyclic aromatic hydrocarbons in the presence of Tenax and XAD4 were examined over the course of 216 h. Changes in the PAH concentrations in dredged sediments using five different seed plants during a short time of period (10 days) were also followed. Using chemical extraction techniques with Tenax and XAD4, a time of around 24 h is enough to achieve equilibrium for all four PAHs. Results showed good agreement between the seed accumulation and PAH extraction methods with both agents. If we compare the two extraction techniques, XAD4 gave better results for phenanthrene, pyrene and benzo(a)pyrene, and Tenax gave better results for chrysene. PMID:26490893

  18. Optimizing catalysis conditions to decrease aromatic hydrocarbons and increase alkanes for improving jet biofuel quality.

    PubMed

    Cheng, Jun; Li, Tao; Huang, Rui; Zhou, Junhu; Cen, Kefa

    2014-04-01

    To produce quality jet biofuel with high amount of alkanes and low amount of aromatic hydrocarbons, two zeolites of HY and HZSM-5 supporting Ni and Mo were used as catalysts to convert soybean oil into jet fuel. Zeolite HY exhibited higher jet range alkane selectivity (40.3%) and lower jet range aromatic hydrocarbon selectivity (23.8%) than zeolite HZSM-5 (13.8% and 58.9%). When reaction temperature increased from 330 to 390°C, yield of jet fuel over Ni-Mo/HY catalyst at 4 MPa hydrogen pressure increased from 0% to 49.1% due to the shift of reaction pathway from oligomerization to cracking reaction. Further increase of reaction temperature from 390 to 410°C resulted in increased yield of jet range aromatic hydrocarbons from 18.7% to 30%, which decreased jet fuel quality. A high yield of jet fuel (48.2%) was obtained at 1 MPa low hydrogen pressure over Ni (8 wt.%)-Mo (12 wt.%)/HY catalyst. PMID:24656484

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

    PubMed

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

    2016-04-01

    Exhaust particulate from compression ignition (CI) engines running on engine and chassis dynamometers was studied. Particulate dichloromethane extracts were qualitatively and quantitatively analyzed for polycyclic aromatic hydrocarbons (PAHs) and biomarkers by gas chromatography with flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS). PAH group profiles were made and the PAH group shares according to the number of rings (2 or 3; 4; 5 or more) as well as diagnostic indices were calculated. Values of geochemical ratios of selected biomarkers and alkyl aromatic hydrocarbons were compared with literature values. A geochemical interpretation was carried out using these values and biomarker and alkyl aromatic hydrocarbon distributions. It has been shown that geochemical features are unequivocally connected to the emission of fossil fuels and biofuels burned in CI engines. The effect of the exothermic combustion process is limited to low-molecular-weight compounds, which shows that the applied methodology permits source identification of PAHs coexisting in the particulate emitted. PMID:26728284

  20. [Halogenated polycyclic aromatic hydrocarbons in surface sediments of Maozhou River, Shenzhen].

    PubMed

    Sun, Jian-Lin; Ni, Hong-Gang; Ding, Chao; Zeng, Hui

    2012-09-01

    Surface sediments collected from the Maozhou River watershed in Shenzhen were analyzed for the concentration levels and spatial distribution characteristics of halogenated polycyclic aromatic hydrocarbons (HPAHs) using GC-MS. Total concentrations of three chlorinated polycyclic aromatic hydrocarbons (ClPAHs) and six brominated polycyclic aromatic hydrocarbons (BrPAHs) of concern ranged from 3.00 to 301 ng x g(-1) and 7.52 to 285 ng x g(-1), respectively. Source appointments indicated that the HPAHs in these surface sediments were mainly derived from waste incineration, fossil fuel combustion, vehicle emission, and burning of crop straw, accounting for 40%, 20.5% 11.9%, and 11.7% of the total loading, respectively. Additionally, the toxic equivalency quotients (TEQ) of total ClPAHs and BrPAHs ranged from 7.95 to 38.1 pg x g(-1) and 38.1 to 105 pg x g(-1) respectively. Finally, the relationships between the HPAHs levels and different land use types were examined. Results indicated that the levels of HPAHs in surface sediments showed a decreasing trend after the first increase to the peak with the density of industrial land, but inversely proportional to the density of agricultural land. PMID:23243864

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

    PubMed

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

    2010-09-01

    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 (GCxGC-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 aromatic UCM hydrocarbon fraction isolated from Tia Juana Pesado (TJP) crude oil were examined. 48h exposure of mussels to the aromatic hydrocarbon fraction (F2) resulted in tissue concentrations of 900microgg(-1) (dry wt.) and approximately 45% decrease in clearance rate. Over 90% of the hydrocarbon burden corresponded to an UCM. Following a 5day recovery period, GCxGC-ToF-MS analysis of the tissues indicated depuration of most accumulated hydrocarbons and clearance rates returned to those observed in controls. To assess the potential of biodegradation to reduce UCM toxicity, TJP F2 was exposed to bacteria isolated from Whitley Bay, UK, for 46days. Mussels exposed to the undegraded TJP F2 from the abiotic control exhibited a reduction in clearance rate comparable with values for the pure crude oil TJP F2. Clearance rates of mussels exposed to biodegraded TJP F2 were statistically similar to seawater controls, suggesting biodegradation had reduced the TJP F2 toxicity. GCxGC-ToF-MS analysis revealed the same compound groups in the tissue of mussels exposed to pure TJP F2, undegraded TJP F2 and biodegraded TJP F2 samples; however >300 fewer compounds were observed in the biodegraded (954 compounds) compared to the undegraded TJP F2 (1261). The compound distributions were markedly different, possibly accounting for the decrease in toxicity. Extraction and analysis of pelleted bacterial cell material revealed that a significant proportion of the TJP F2 had adsorbed onto the cells. Thus extreme care must be taken in interpreting biodegradation data from recalcitrant UCM hydrocarbons. PMID:20542318

  2. The effect of strain rate on polycyclic aromatic hydrocarbon (PAH) formation in acetylene diffusion flames

    SciTech Connect

    Yamamoto, Manabu; Duan, Shici; Senkan, Selim

    2007-11-15

    Acetylene is a ubiquitous combustion intermediate that is also believed to be the major precursor for aromatic, polycyclic aromatic hydrocarbon (PAH), and soot formation in both hydrocarbon and halogenated hydrocarbon flames. However, in spite of its important role as a flame intermediate, the detailed chemical structures of acetylene diffusion flames have not been studied in the past. Here the detailed chemical structures of counterflow diffusion flames of acetylene at strain rates of 37.7 and 50.3 s{sup -1} are presented. Both flames possessed the same carbon density of 0.37 g/L corresponding to an acetylene mole fraction of 0.375 in argon on the fuel side, and an oxygen mole fraction of 0.22 in argon on the oxidizer side. Concentration profiles of a large number of major, minor, and trace species, including a wide spectrum of aromatics and PAH, have been determined by direct sampling from flames using a heated quartz microprobe coupled to an online gas chromatograph/mass selective detector (GC/MSD). Temperature profiles were made using a thermocouple and the rapid insertion technique. Although the major species concentrations were nearly the same in the two flames, the mole fraction profiles of trace combustion by-products were significantly lower in the higher-strain-rate flame, by nearly two orders of magnitude for PAH. These comparative results provide new information on the trace chemistries of acetylene flames and should be useful for the development and validation of detailed chemical kinetic mechanisms describing the formation of toxic by-products in the combustion of hydrocarbons and halogenated hydrocarbons. (author)

  3. Remediation of a chlorinated aromatic hydrocarbon in water by photoelectrocatalysis.

    PubMed

    Nissen, Silke; Alexander, Bruce D; Dawood, Ilyas; Tillotson, Martin; Wells, Richard P K; Macphee, Donald E; Killham, Kenneth

    2009-01-01

    Photoelectrocatalysis driven by visible light offers a new and potentially powerful technology for the remediation of water contaminated by organo-xenobiotics. In this study, the performance of a visible light-driven photoelectrocatalytic (PEC) batch reactor, applying a tungsten trioxide (WO(3)) photoelectrode, to degrade the model pollutant 2,4-dichlorophenol (2,4-DCP) was monitored both by toxicological assessment (biosensing) and chemical analysis. The bacterial biosensor used to assess the presence of toxicity of the parent molecule and its breakdown products was a multicopy plasmid lux-marked E. coli HB101 pUCD607. The bacterial biosensor traced the removal of 2,4-DCP, and in some case, its toxicity response suggests the identification of transient toxic intermediates. The loss of the parent molecule, 2,4-DCP determined by HPLC, corresponded to the recorded photocurrents. Photoelectrocatalysis offers considerable potential for the remediation of chlorinated hydrocarbons, and that the biosensor based toxicity results identified likely compatibility of this technology with conventional, biological wastewater treatment. PMID:18789564

  4. Evaluation of field methods for estimating exposure of children in low-income families to polycyclic aromatic hydrocarbons

    SciTech Connect

    Wilson, N.K.; Chuang, J.C.; Lyu, C.

    1996-12-31

    Children in low-income families may have higher exposures to polycyclic aromatic hydrocarbons (PAH) and related compounds than children in higher-income families. These higher exposures could result from the location of their homes, nearer to industrial sites and traffic; from poorer diet; from environmental tobacco smoke; or other causes. The study was designed to evaluate methods and estimate the range of total exposures of low-income children to PAH through various pathways. Nonsmoking participants with preschool children, incomes at or below the official US poverty level, and space heating in their homes were recruited. The PAH concentrations were measured in the household indoor and outdoor air, house dust, and yard soil, and in the diet of both an adult and a preschool child living in the home. An initial study in two homes and an additional study of nine homes, four urban and five rural, during the heating season were completed. The problems and successes encountered in the recruitment process and selected results of the heating season measurements are summarized in the paper.

  5. Polycyclic aromatic hydrocarbons in deposited bedroom dust collected from Xinxiang, a fast developing city in North China.

    PubMed

    Yang, Zhong-Zhi; Li, Yong-Fang; Fan, Jing

    2015-01-01

    To investigate the contamination levels of polycyclic aromatic hydrocarbons (PAHs) in the indoor environment, 16 PAHs were measured in 20 deposited bedroom dust (DBD) samples collected from four residential areas in Xinxiang City. The total PAH concentrations (∑PAHs, defined as the sum of 16 PAHs) in 20 DBD samples ranged from 1.47 to 21.8 μg/g dry weight. PAH ratios indicated that main sources of PAHs in most DBD samples were coal, grasses, and wood combustion. Correlation analysis showed that there were no significant positive correlations between ∑PAH concentrations in DBD and the number of family members or duration of residence. Analysis using the t test revealed that tobacco smoke was a source of PAHs in DBD and that an unattached kitchen may be a significant influencing factor related to PAHs in DBD collected from residential areas in Xinxiang City. Our results showed that the kitchen exhaust fan or hood had no significant influence on total PAHs in DBD, and there was no significant difference in ∑PAH concentrations in DBD in homes which used liquefied petroleum gas and those which used natural gas. PMID:25404542

  6. Spatial and Temporal Trends of Polycyclic Aromatic Hydrocarbons and Other Traffic-Related Airborne Pollutants in New York City

    PubMed Central

    NARVEZ, RAFAEL F.; HOEPNER, LORI; CHILLRUD, STEVEN N.; YAN, BEIZHAN; GARFINKEL, ROBIN; WHYATT, ROBIN; CAMANN, DAVID; PERERA, FREDERICA P.; KINNEY, PATRICK L.; MILLER, RACHEL L.

    2008-01-01

    Traffic-related air pollutants have been associated with adverse health effects. We hypothesized that exposure to polycyclic aromatic hydrocarbons (PAHs), elemental carbon (EC, diesel indicator), particulate matter (PM2.5), and a suite of metals declined from 1998 to 2006 in NYC due to policy interventions. PAH levels from personal monitoring of pregnant mothers participating in the Columbias Center for Childrens Environmental Health birth cohort study, and EC, PM2.5, and metal data from five New York State Department of Environmental Conservation stationary monitors were compared across sites and over time (19982006). Univariate analysis showed a decrease in personal PAHs exposures from 1998 to 2006 (p < 0.0001). After controlling for environmental tobacco smoke, indoor heat, and cooking, year of personal monitoring remained a predictor of decline in ?8PAHs (? = ?0.269, p < 0.001). Linear trend analysis also suggested that PM2.5 declined (p = 0.09). Concentrations of EC and most metals measured by stationary site monitors, as measured by ANOVA, did not decline. Across stationary sites, levels of airborne EC and metals varied considerably. By contrast PM2.5 levels were highly intercorrelated (values ranged from 0.725 to 0.922, p < 0.01). Further policy initiatives targeting traffic-related air pollutants may be needed for a greater impact on public health. PMID:18939566

  7. THE EFFECTS OF EQUIVALENCE RATIO ON THE FORMATION OF POLYCYCLIC AROMATIC HYDROCARBONS AND SOOT IN PREMIXED ETHANE FLAMES. (R825412)

    EPA Science Inventory

    Abstract

    The formation of polycyclic aromatic hydrocarbons (PAH) and soot has been investigated in atmospheric-pressure, laminar, ethane/oxygen/argon premixed flames as a function of mixture equivalence ratio. Mole fraction profiles of major products, trace aromatics, ...

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

    NASA Astrophysics Data System (ADS)

    Landera, Alexander

    2013-12-01

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

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

    PubMed

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

    2015-12-25

    In previous decades, white-rot fungi as bioremediation agents have been the subjects of scientific research due to the potential use of their unspecific oxidative enzymes. However, some non-white-rot fungi, mainly belonging to the Ascomycota and Zygomycota phylum, have demonstrated their potential in the enzymatic transformation of environmental pollutants, thus overcoming some of the limitations observed in white-rot fungi with respect to growth in neutral pH, resistance to adverse conditions and the capacity to surpass autochthonous microorganisms. Despite their presence in so many soil and water environments, little information exists on the enzymatic mechanisms and degradation pathways involved in the transformation of hydrocarbons by these fungi. This review describes the bioremediation potential of non-ligninolytic fungi with respect to chlorinated hydrocarbons and polycyclic aromatic hydrocarbons (PAHs) and also shows known conversion pathways and the prospects for future research. PMID:25681797

  10. Environmental degradation of polluting aromatic and aliphatic hydrocarbons: a case study.

    PubMed

    Osuji, Leo C; Ozioma, Achugasim

    2007-03-01

    Oil extracts of Ukpeliede spill samples from Niger Delta (Nigeria) were analyzed by gas chromatography. The amount of polycyclic aromatic hydrocarbons (PAHs), especially the lower-molecular-weight naphthene, fluorine, phenathrene, pyrene, and benzo[a]anthracene, decreased within the sampling intervals of 2 months and 5 months. There was a predominance of three-to-six-ring PAHs over the two-ring PAHs. There was marked disappearance of n-C8 to n-C11 hydrocarbon fractions and the acyclic isoprenoids (pristane and phytane). The depletion of these molecules within the two sampling intervals suggests the possible attenuation of hydrocarbons as a result of the environmental modification within the set interval. PMID:17372944

  11. Combined Effects of Prenatal Polycyclic Aromatic Hydrocarbons and Material Hardship on Child IQ

    PubMed Central

    Vishnevetsky, Julia; Tang, Deliang; Chang, Hsin-Wen; Roen, Emily L.; Wang, Ya; Rauh, Virginia; Wang, Shuang; Miller, Rachel L.; Herbstman, Julie; Perera, Frederica P.

    2015-01-01

    Importance Polycyclic aromatic hydrocarbons are common carcinogenic and neurotoxic urban air pollutants. Toxic exposures, including air pollution, are disproportionately high in communities of color and frequently co-occur with chronic economic deprivation. Objectives We examined whether the association between child IQ and prenatal exposure to polycyclic aromatic hydrocarbons differed between groups of children whose mothers reported high vs. low material hardship during their pregnancy and through child age 5. We tested statistical interactions between hardships and polycyclic aromatic hydrocarbons, as measured by DNA adducts in cord blood, to determine whether material hardship exacerbated the association between adducts and IQ scores. Design Prospective cohort. Participants were recruited from 1998 to 2006 and followed from gestation through age 7 years. Setting Urban community (New York City) Participants A community-based sample of 276 minority urban youth Exposure measure Polycyclic aromatic hydrocarbon-DNA adducts in cord blood as an individual biomarker of prenatal polycyclic aromatic hydrocarbon exposure. Maternal material hardship self-reported prenatally and at multiple timepoints through early childhood. Main outcome measure Child IQ at 7 years assessed using the Wechsler Intelligence Scale for Children. Results Significant inverse effects of high cord PAH-DNA adducts on full scale IQ, perceptual reasoning and working memory scores were observed in the groups whose mothers reported a high level of material hardship during pregnancy or recurring high hardship into the child’s early years, and not in those without reported high hardship. Significant interactions were observed between high cord adducts and prenatal hardship on working memory scores (β=−8.07, 95% CI (−14.48, −1.66) and between high cord adducts and recurrent material hardship (β=−9.82, 95% CI (−16.22, −3.42). Conclusion The findings add to other evidence that socioeconomic disadvantage can increase the adverse effects of toxic physical “stressors” like air pollutants. Observed associations between high cord adducts and reduced IQ were significant only among the group of children whose mothers reported high material hardship. These results indicate the need for a multifaceted approach to prevention. PMID:25912623

  12. The effect of aromatization on the isotopic compositions of hydrocarbons during early diagenesis

    NASA Technical Reports Server (NTRS)

    Freeman, K. H.; Boreham, C. J.; Summons, R. E.; Hayes, J. M.

    1994-01-01

    Polycyclic aromatic hydrocarbons with varying degrees of aromatization were isolated from the Eocene Messel Shale (Rheingraben, Germany). The high abundances of these compounds and their structural resemblances to cyclic triterpenoid lipids are consistent with derivation from microbial rather than thermal processes. Compounds structurally related to oleanane contain from five to nine double bonds; those within a series of aromatized hopanoids contain from three to nine. All are products of diagenetic reactions that remove hydrogen or methyl groups, and, in several cases, break carbon-carbon bonds to open rings. Aromatized products are on average depleted in 13C relative to possible precursors by l.2% (range: l.5% enrichment to 4% depletion, n = 9). The dependence of 13C content on the number of double bonds is not, however, statistically significant and it must be concluded that there is no strong evidence for isotopic fractionation accompanying diagenetic aromatization. Isotopic differences between series (structures related to ursane, des-A-ursane, des-A-lupane, des-A-arborane, and possibly, des-A-gammacerane are present) are much greater, indicating that 13C contents are controlled primarily by source effects. Fractionations due to chromatographic isotope effects during HPLC ranged from 0.1 to 2.8%.

  13. Release of bound aromatic hydrocarbons from late Archean and Mesoproterozoic kerogens via hydropyrolysis

    NASA Astrophysics Data System (ADS)

    Brocks, Jochen J.; Love, Gordon D.; Snape, Colin E.; Logan, Graham A.; Summons, Roger E.; Buick, Roger

    2003-04-01

    Hydrogen-lean kerogens (atomic H/C<0.4) isolated from the 2.5-billion-year-old (Ga) Mt. McRae Shale, Hamersley Group, at Tom Price, Western Australia, were studied via hydropyrolysis, a continuous-flow technique that degrades organic matter in a stream of high-pressure hydrogen assisted by a dispersed Mo catalyst. The hydropyrolysates yielded predominantly phenanthrene and pyrene, and higher polyaromatic hydrocarbons and alkylated homologues were generated in low relative concentrations. Saturated hydrocarbons were not detected. The molecular and carbon isotopic compositions of the hydropyrolysates are very similar to aromatic hydrocarbons obtained by solvent extraction of the host rocks. Because molecular structures covalently attached to kerogen are unaffected by contamination, this indicates that both the bound and extractable aromatic fractions are syngenetic with the host rocks. Therefore, the results of the hydropyrolysis experiments provide compelling evidence for preserved bitumen of Archean age. The very high proportion of nonalkylated polyaromatic hydrocarbons in the hydropyrolysates is consistent with hydrothermal dehydrogenation of the kerogen, and a marked concentration difference of pyrene in rock extracts and hydropyrolysates might be explained by hydrothermal redistribution of the bitumen. The kerogen and bitumen composition is therefore consistent with models suggesting a hydrothermal origin for the giant iron ore deposits at Mt. Tom Price. Comparison of the Archean samples with hydropyrolysates from immature Mesoproterozoic kerogens from the Roper Group, McArthur Basin, Northern Territory, and with pyrolysis experiments on Proterozoic kerogens in the literature suggests that Precambrian kerogens are frequently highly aromatic and lipid-poor regardless of their degree of thermal preservation.

  14. Nitro-polycyclic aromatic hydrocarbons and polycyclic aromatic hydrocarbons in particulate matter in an urban area of a tropical region: Ho Chi Minh City, Vietnam

    NASA Astrophysics Data System (ADS)

    Hien, To Thi; Thanh, Le Tu; Kameda, Takayuki; Takenaka, Norimichi; Bandow, Hiroshi

    Urban air pollution in many cities of the developing world in Asia, particularly in Vietnam, is increasing significantly. Atmospheric particulate matter pollution is dangerous to the health of millions of people and is a particular concern. In this study, two nitro-polycyclic aromatic hydrocarbons (nitro-PAHs), 1-nitropyrene (1-NP) and 2-nitrofluoranthene (2-NF) and several polycyclic aromatic hydrocarbons (PAHs)—highly carcinogenic and mutagenic compounds—were quantified in particulate matter (PM) collected at three ambient air sites (VNU, ITTE and DOSTE) in an urban area of Ho Chi Minh City, Vietnam, between January 2005 and March 2006. The DOSTE site was close to ground level on a street with a high traffic density. 2-NF was more abundant than 1-NP at all sampling sites. Concentrations of 1-NP and PAHs at the traffic site (DOSTE) were higher than those at the other sites (VNU and ITTE). The daytime/nighttime distribution of 2-NF and the 2-NF/1-NP ratios were used to evaluate the gas-phase formation of 2-NF and its formation route. The average ratios of 2-NF/1-NP at the VNU and ITTE sites were much higher than those at the DOSTE site, suggesting that the gas-phase reactions are an important source of 2-NF in the ambient air. The higher nighttime concentration of 2-NF observed at the VNU and ITTE sites and the converse result observed for the traffic site indicates that an NO 3 radical-initiated reaction is the dominant route for 2-NF formation in ambient air, while the majority of 2-NF at the traffic site may be attributed to OH radical-initiated reactions.

  15. Evaluation of matrix solid-phase dispersion extraction for the determination of polycyclic aromatic hydrocarbons in household dust with the aid of experimental design and response surface methodology.

    PubMed

    Christopoulou, Ourania D; Sakkas, Vasilios A; Albanis, Triantafyllos A

    2012-12-01

    A simple, fast, and inexpensive procedure for sample preparation based on matrix solid-phase dispersion was developed for the determination of Environmental Protection Agency 16 priority polycyclic aromatic hydrocarbons in indoor dust samples. Parameters that affect the extraction efficiency such as type of dispersant, elution solvent, and solvent volume were evaluated and optimized with the aid of experimental design and response surface methodology. Analysis was performed by HPLC coupled with UV-Vis diode array detector (UV-DAD). For verification, a GC coupled with a mass spectrometer in SIM mode was also applied. Recoveries obtained were from 53 to 120% for all target analytes with detection limits ranging from 0.2 to 10 ng/g and 0.2 to 2 ng/g for LC-UV-DAD and GC-MS, respectively. The optimized method was used for the analysis of 11 household dust samples collected from private houses. PMID:23125095

  16. Combination processing of pyrolysis naphtha to obtain aromatic hydrocarbons and high-octane gasolines

    SciTech Connect

    Guseinova, A.D.; Asker-Zade, S.M.; Mubarak, A.R.M.

    1994-07-01

    In the pyrolysis of hydrocarbon feedstocks, production of the desired monomer - ethylene - is accompanied by the formation of pyrolysis naphtha, which has a high content of benzene (30%) and hence is processed solely for benzene recovery. In view of the increased demand for automotive gasolines, this processing scheme is extremely illogical. One of the possible means for rational utilization of pyrolysis naphtha is the combined production of high-octane unleaded gasolines and aromatic hydrocarbons, mainly benzene. With such a scheme, the pyrolysis naphtha and the fractions segregated from the naphtha can be processed separately. Another problem that requires a fast solution is the production of ecologically clean modified gasolines. The production and use of leaded gasolines are being phased out universally, in the interest of improving environmental health. For the improvement of octane number, tetraethyllead is being replaced by oxygen-containing compounds, mainly methyl tert-butyl ether and methyl tert-amyl ether. These oxygenates are used at concentrations of 2.0-2.7% in the gasoline. The content of aromatic hydrocarbons (particularly benzene) is limited to 1%. In this article we will describe an optimal scheme for processing pyrolysis naphtha, yielding benzene and AI-93 high-quality unleaded gasoline.

  17. Reaction Dynamics in Astrochemistry: Low-Temperature Pathways to Polycyclic Aromatic Hydrocarbons in the Interstellar Medium

    NASA Astrophysics Data System (ADS)

    Kaiser, Ralf I.; Parker, Dorian S. N.; Mebel, Alexander M.

    2015-04-01

    Bimolecular reactions of phenyl-type radicals with the C4 and C5 hydrocarbons vinylacetylene and (methyl-substituted) 1,3-butadiene have been found to synthesize polycyclic aromatic hydrocarbons (PAHs) with naphthalene and 1,4-dihydronaphthalene cores in exoergic and entrance barrierless reactions under single-collision conditions. The reaction mechanism involves the initial formation of a van der Waals complex and addition of a phenyl-type radical to the C1 position of a vinyl-type group through a submerged barrier. Investigations suggest that in the hydrocarbon reactant, the vinyl-type group must be in conjugation with a -C≡CH or -HC=CH2 group to form a resonantly stabilized free radical intermediate, which eventually isomerizes to a cyclic intermediate followed by hydrogen loss and aromatization (PAH formation). The vinylacetylene-mediated formation of PAHs might be expanded to more complex PAHs, such as anthracene and phenanthrene, in cold molecular clouds via barrierless reactions involving phenyl-type radicals, such as naphthyl, which cannot be accounted for by the classical hydrogen abstraction-acetylene addition mechanism.

  18. Reaction dynamics in astrochemistry: low-temperature pathways to polycyclic aromatic hydrocarbons in the interstellar medium.

    PubMed

    Kaiser, Ralf I; Parker, Dorian S N; Mebel, Alexander M

    2015-04-01

    Bimolecular reactions of phenyl-type radicals with the C4 and C5 hydrocarbons vinylacetylene and (methyl-substituted) 1,3-butadiene have been found to synthesize polycyclic aromatic hydrocarbons (PAHs) with naphthalene and 1,4-dihydronaphthalene cores in exoergic and entrance barrierless reactions under single-collision conditions. The reaction mechanism involves the initial formation of a van der Waals complex and addition of a phenyl-type radical to the C1 position of a vinyl-type group through a submerged barrier. Investigations suggest that in the hydrocarbon reactant, the vinyl-type group must be in conjugation with a -C≡CH or -HC=CH2 group to form a resonantly stabilized free radical intermediate, which eventually isomerizes to a cyclic intermediate followed by hydrogen loss and aromatization (PAH formation). The vinylacetylene-mediated formation of PAHs might be expanded to more complex PAHs, such as anthracene and phenanthrene, in cold molecular clouds via barrierless reactions involving phenyl-type radicals, such as naphthyl, which cannot be accounted for by the classical hydrogen abstraction-acetylene addition mechanism. PMID:25422849

  19. Docosahexaenoic acid regulates gene expression in HUVEC cells treated with polycyclic aromatic hydrocarbons.

    PubMed

    Gdula-Argasi?ska, Joanna; Czepiel, Jacek; Toto?-?ura?ska, Justyna; Jurczyszyn, Artur; Perucki, William; Wo?kow, Pawe?

    2015-07-16

    The molecular mechanism of inflammation and carcinogenesis induced by exposure of polycyclic aromatic hydrocarbons (PAHs) is not clearly understood. Our study was undertaken due to the strong pro-carcinogenic potential and reactivity of PAH-metabolites, as well as the susceptibility of polyunsaturated fatty acids to oxidation. The aim of this study was to evaluate the pro- or anti-inflammatory impact of n-3 docosahexaenoic acid on human primary umbilical vein endothelial cells (HUVEC) exposed to polycyclic aromatic hydrocarbons. We analysed the influence of docosahexaenoic acid (DHA) and/or PAHs supplementation on the fatty acid profile of cell membranes, on cyclooxygenase-2 (COX-2), aryl hydrocarbon receptor (AHR), and glutathione S transferase Mu1 (GSTM1) protein expression as well as on the prostaglandin synthase 2 (PTGS2), AHR, GSTM1, PLA2G4A, and cytochrome P450 CYP1A1 gene expression. We observed that COX-2 and AHR protein expression was increased while GSTM1 expression was decreased in cells exposed to DHA and PAHs. Docosahexaenoic acid down-regulated CYP1A1 and up-regulated the AHR and PTGS2 genes. Our findings suggested that DHA contributes significantly to alleviate the harmful effects caused by PAHs in endothelial cells. Moreover, these results suggest that a diet rich in n-3 fatty acids is helpful to reduce the harmful effects of PAHs exposure on human living in heavily polluted areas. PMID:25956473

  20. Reflectance spectroscopy (350-2500 nm) of solid-state polycyclic aromatic hydrocarbons (PAHs)

    NASA Astrophysics Data System (ADS)

    Izawa, M. R. M.; Applin, D. M.; Norman, L.; Cloutis, E. A.

    2014-07-01

    Polycyclic aromatic hydrocarbons (PAHs) are organic compounds based on fused aromatic rings, and are formed in a variety of astrophysical, solar nebula and planetary processes. Polycyclic aromatic hydrocarbons are known or suspected to occur in a wide variety of planetary settings including icy satellites, Titan’s hazes, carbonaceous meteorites, comet nuclei, ring particles; and terrestrial organic-rich lithologies such as coals, asphaltites, and bituminous sands. Relatively few measurements of the visible and near-infrared spectra of PAHs exist, yet this wavelength region (350-2500 nm) is widely used for remote sensing. This study presents detailed analyses of the 350-2500 nm reflectance spectra of 47 fine-grained powders of different high-purity solid-state PAHs. Spectral properties of PAHs change with variations in the number and connectivity of linked aromatic rings and the presence and type of side-groups and heterocycles. PAH spectra are characterized by three strong features near ∼880 nm, ∼1145 nm, and ∼1687 nm due to overtones of νCH fundamental stretching vibrations. Some PAHs are amenable to remote detection due to the presence of diagnostic spectral features, including: Nsbnd H stretching overtones at 1490-1515 nm in NH- and NH2-bearing PAHs, aliphatic or saturated bond Csbnd H overtone vibrations at ∼1180-1280 nm and ∼1700-1860 nm; a broad asymmetric feature between ∼1450 nm and ∼1900 nm due to Osbnd H stretching overtones in aromatic alcohols, Csbnd H and Cdbnd O combinations near ∼2000-2010 nm and ∼2060-2270 nm in acetyl and carboxyl-bearing PAHs. Other substituents such as sulphonyl, thioether ether and carboxyl heterocycles, or cyano, nitrate, and aromatic side groups, do not produce well-resolved diagnostic spectral features but do cause shifts in the positions of the aromatic Csbnd H vibrational overtone features. Fluorescence is commonly suppressed by the presence of heterocycles, side-groups and in many non-alternant PAHs. The spectral characteristics of PAHs offer the potential, under suitable circumstances, for remote characterization of the classes of PAH present and in some cases, identification of particular heterocyclic or side-group substituents.

  1. A Theoretical Study on the Vibrational Spectra of Polycyclic Aromatic Hydrocarbon Molecules with Aliphatic Sidegroups

    NASA Astrophysics Data System (ADS)

    Sadjadi, SeyedAbdolreza; Zhang, Yong; Kwok, Sun

    2015-03-01

    The role of aliphatic side groups in the formation of astronomical unidentified infrared emission (UIE) features is investigated by applying the density functional theory to a series of molecules with mixed aliphatic-aromatic structures. The effects of introducing various aliphatic groups to a fixed polycyclic aromatic hydrocarbon (PAH) core (ovalene) are studied. Simulated spectra for each molecule are produced by applying a Drude profile at T = 500 K while the molecule is kept at its electronic ground state. The vibrational normal modes are classified using a semi-quantitative method. This allows us to separate the aromatic and aliphatic vibrations, and therefore provides clues to what types of vibrations are responsible for the emissions bands at different wavelengths. We find that many of the UIE bands are not pure aromatic vibrational bands but may represent coupled vibrational modes. The effects of aliphatic groups on the formation of the 8 μm plateau are quantitatively determined. The vibrational motions of methyl (-CH3) and methylene (-CH2 -) groups can cause the merging of the vibrational bands of the parent PAH and the forming of broad features. These results suggest that aliphatic structures can play an important role in the UIE phenomenon.

  2. Friction of iron lubricated with aliphatic and aromatic hydrocarbons and halogenated analogs

    NASA Technical Reports Server (NTRS)

    Buckley, D. H.

    1976-01-01

    The influence of oxygen and various organic molecules on the reduction of the friction of an iron (011) single crystal surface was investigated. A comparison was made between aliphatic and aromatic structures, all of which contained six carbon atoms, and among various halogen atoms. Results of the investigation indicate that hexane and benzene give similar friction coefficients over a range of loads except at very light loads. At light loads, the friction decreased with an increase in the load where the halogens fluorine and chlorine are incorporated into the benzene molecular structure; however, over the same load range when bromine and iodine were present, the friction was relatively unchanged. The aliphatic compound chlorohexane exhibited lower friction coefficients than the aromatic structure chlorobenzene at very light loads. With the brominated benzene structures, however, friction was essentially the same. Oxygen was more effective in reducing friction than were the simple hydrocarbons.

  3. POLYCYCLIC AROMATIC HYDROCARBONS WITH ARMCHAIR EDGES AND THE 12.7 μm BAND

    SciTech Connect

    Candian, A.; Tielens, A. G. G. M.; Sarre, P. J.

    2014-08-10

    In this Letter, we report the results of density functional theory calculations on medium-sized neutral polycyclic aromatic hydrocarbon (PAH) molecules with armchair edges. These PAH molecules possess strong C-H stretching and bending modes around 3 μm and in the fingerprint region (10-15 μm), and also strong ring deformation modes around 12.7 μm. Perusal of the entries in the NASA Ames PAHs Database shows that ring deformation modes of PAHs are common, although generally weak. Therefore, we propose that armchair PAHs with N{sub C} > 65 are responsible for the 12.7 μm aromatic infrared band in H II regions and discuss the astrophysical implications in the context of the PAH life cycle.

  4. ORIGIN OF ORGANIC GLOBULES IN METEORITES: LABORATORY SIMULATION USING AROMATIC HYDROCARBONS

    SciTech Connect

    Saito, Midori; Kimura, Yuki

    2009-10-01

    Analogs of organic hollow globules, which have been found in carbonaceous chondrite meteorites and interplanetary dust particles, were synthesized in our laboratory from benzene and anthracene using plasma. Our results suggest that organic globules could be made from aromatic rings in circumstellar envelopes around evolved stars. The hollow interior could be formed by coagulation of vacancies, formed by electronic excitation and/or knock-out of carbon atoms following irradiation by plasma particles such as protons and He{sup +} ions. This experimental result suggests that organic globules are possibly the final products in the evolution of carbonaceous matter from acetylene and benzene to polycyclic aromatic hydrocarbons in ejecta gas from evolved stars.

  5. Promising approaches towards biotransformation of polycyclic aromatic hydrocarbons with Ascomycota fungi.

    PubMed

    Aranda, Elisabet

    2016-04-01

    The bioremediation of hazardous aromatic pollutants such as polycyclic aromatic hydrocarbons (PAHs) has been extensively studied in recent decades, including the potential use of different phyla of fungi for this purpose. Molecular technologies are starting to reveal that the real players in polluted environments are mainly represented by the phylum Ascomycota and the subphylum Mucoromycotina and, to a lesser extent, the phylum Basidiomycota. Paradoxically, despite their key involvement, these groups of fungi are often treated as a black box, and their potential roles in the transformation of xenobiotics and catabolic pathways remain poorly understood. The complex intracellular metabolism seems to play a major role in the ability of these fungi to transform or remove PAHs, and their associated enzymes are encoded in the xenome. Functional genomics offers novel information about this enzymatic system, which is widely distributed among all phyla. PMID:26722717

  6. Speciation of atmospheric polycyclic aromatic hydrocarbons (PAHs) present during fog time collected submicron particles.

    PubMed

    Singh, Dharmendra Kumar; Sharma, Swati; Habib, Gazala; Gupta, Tarun

    2015-08-01

    Airborne submicron particles (PM1) were collected using PM1 sampler during the fog-dominated days (December 2013-January 2014). PM1 values varied between 58.12 μg/m(3) and 198.75 μg/m(3), and average mass concentration was 162.33 ± 38.25 μg/m(3) while total average concentration of particle-associated polycyclic aromatic hydrocarbon (PAHs) determined was 616.31 ± 30.31 ng/m(3). This is a signal for an alarming high pollution level at this site situated in the Indo-Gangetic Plain (IGP). PAHs were extracted from filters using toluene and acetonitrile. Quantitative measurements of polycyclic aromatic hydrocarbons (PAHs) were carried out using the high performance liquid chromatography (HPLC) technique. The extracts were analyzed for 16 target polycyclic aromatic hydrocarbons (PAHs) including carcinogenic compound benzo(a)pyrene (19.86 ± 38.98 ng/m(3)). Fluoranthene, benzo(a)anthracene, anthracene, and fluorene were the predominant compounds found in the samples collected during foggy days. Based on number of rings, four-ring PAH compounds had maximum contribution (43%) in this fog time collected submicron particles followed by three-ring (21%), five-ring (20%), six-ring (13%), and two-ring (3%), respectively. In winter and foggy days, wood and coal combustion and biomass burning also significantly contribute to the PAH levels. However, diagnostic ratio suggests diesel emissions as the prime source of PAHs at this sampling site. PMID:25903173

  7. Carbon and Hydrogen Stable Isotope Fractionation Associated with the Aerobic and Anaerobic Degradation of Saturated and Alkylated Aromatic Hydrocarbons.

    PubMed

    Musat, Florin; Vogt, Carsten; Richnow, Hans H

    2016-01-01

    Saturated hydrocarbons (alkanes) and alkylated aromatic hydrocarbons are abundant environmental compounds. Hydrocarbons are primarily removed from the environment by biodegradation, a process usually associated with moderate carbon and significant hydrogen isotope fractionation allowing monitoring of biodegradation processes in the environment. Here, we review the carbon and hydrogen stable isotope fractionation associated with the cleavage of C-H bonds at alkyl chains of hydrocarbons. Propane, n-butane and ethylbenzene were used as model components for alkyl moieties of aliphatic and aromatic hydrocarbons with emphasis on the cleavage of the C-H bond without the involvement of molecular oxygen. The carbon and hydrogen isotope fractionation factors were further used to explore the diagnostic potential for characterizing the mode of bond cleavage under oxic and anoxic conditions. x039B; factors, calculated to correlate carbon and hydrogen fractionation, allowed to distinguish between aerobic and anaerobic biodegradation processes in the environment. PMID:26959878

  8. Interrelationship of Pyrogenic Polycyclic Aromatic Hydrocarbon (PAH) Contamination in Different Environmental Media

    PubMed Central

    Kim, Seung-Kyu; Lee, Dong Soo; Shim, Won Joon; Yim, Un Hyuk; Shin, Yong-Seung

    2009-01-01

    Interrelationships between pyrogenic polycyclic aromatic hydrocarbons (PAHs) were assessed in air, soil, water, sediment, and tree leaves by using multi-media monitoring data. Concurrent concentration measurements were taken bimonthly for a year for the multi-media at urban and suburban sites. PAH level correlations between air and other media were observed at the urban site but were less clear at the suburban site. Considering a closer PAHs distribution/fate characteristics to soil than suspended solids, contamination in sediment seemed to be governed primarily by that in soil. The partitioning of PAHs in waters could be better accounted for by sorption onto black carbon and dissolved organic carbon. PMID:22303141

  9. Analysis of polycyclic aromatic hydrocarbons in air particulate matter from a light industrialized urban area

    SciTech Connect

    Cretney, J.R.; Lee, H.K.; Wright, G.J.; Swallow, W.H.; Taylor, M.C.

    1985-05-01

    Levels of polycyclic aromatic hydrocarbons (PAH) have been measured in the air particulate matter (APM) of a lightly industrialized urban area in which the main sources of PAH are domestic fires and automobiles. The PAH were analyzed by glass capillary gas chromatography combined with mass spectrometry. Statistical analysis of the results using 26 PAH allows the relative contribution of the two sources to be estimated and shows that during periods of heavy pollution (APM > 100 ..mu..g m/sup -3/) domestic fires are the main contributors. A simpler ratio, ln (1 + (benzofluoranthenes)/(total PAH)) - ln (1 + (benzo(ghi)perylene)/(total PAH)), gives similar discrimination.

  10. Palladium-catalyzed oxidative carbonylation for the synthesis of polycyclic aromatic hydrocarbons (PAHs).

    PubMed

    Ji, Fanghua; Li, Xianwei; Wu, Wanqing; Jiang, Huanfeng

    2014-11-21

    A direct and facile palladium-catalyzed C-H bond oxidative carbonylation reaction and oxidative cyclization for the synthesis of polycyclic aromatic hydrocarbons (PAHs) is reported herein. The intramolecular cyclocarbonylation, through C-H activation and C-C, C-O bond formations under mild conditions, proceeds smoothly with good functional group tolerance in high to excellent yields. The intramolecular palladium-catalyzed direct oxidative C-H bond functionalization for the C-O bond formation is also demonstrated, which provides an efficient approach for the construction of various PAHs. PMID:25353393

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

    NASA Astrophysics Data System (ADS)

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

    1987-07-01

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

  12. [Extraction characteristics of sequential accelerated solvent extraction for polycyclic aromatic hydrocarbons in environmental mediums].

    PubMed

    Ma, Xiao-xuan; Ran, Yong

    2009-12-01

    Polycyclic aromatic hydrocarbons (PAHs) in two soils, two sediments and an shale from the Pearl River Delta were extracted by sequential accelerated solvent extraction (ASE) with each of four different organic solvents for three times. PAHs in the first extract accounts for more than half of their total contents, and toluene displays the best extraction performance among the four employed solvents. For a given sample the source diagnostic ratios of PAHs in sequential ASE with each solvent are very similar, suggesting the validity of those ratios in source judgement by different extraction methods. PMID:20187409

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

    SciTech Connect

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

    2010-01-20

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

  14. Qsars for photoinduced toxicity: 1. acute lethality of polycyclic aromatic hydrocarbons to daphnia magna'

    SciTech Connect

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

    1994-01-01

    Research with a variety of aquatic species has shown that while polycyclic aromatic hydrocarbons (PAHs) are generally not acutely toxic in conventional laboratory tests, many are extremely toxic in the presence of sunlight. In an effort to develop a model for predicting which PAHs may exhibit photo-induced toxicity, Newsted and Giesy (1987) reported a parabolic relationship between the toxicity and the energy of the triplet state of a variety of PAHs. The authors have reexamined these data and propose a more mechanistic explanation for the prediction of photo-induced PAH toxicity. They sought a molecular descriptor which could be computed from structure rather than measured empirically.

  15. Characterization and source apportionment of polycyclic aromatic hydrocarbons (PAHs) in Sediments from the Bohai Sea, China

    NASA Astrophysics Data System (ADS)

    Liu, Jihua; Hu, Ningjing; Shi, Xuefa

    2015-04-01

    Characterization and source apportionment of polycyclic aromatic hydrocarbons (PAHs) in Sediments from the Bohai Sea, China Liu Jihua, Hu Ningjing, Shi Xuefa First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, China Polycyclic aromatic hydrocarbons (PAHs) are a class of ubiquitous organic contaminants in the environment. Indeed, 16 PAH compounds have been listed as priority pollutants by the United States Environmental Protection Agency and the European Union because of their potential toxicity to humans and ecosystems. As POPs are released or escape into the environment, their global accumulation in marine sediments generates a complex balance between inputs and outputs. Furthermore, PAHs in coastal sediments can serve as effective tracers of materials transport from land-to-sea (Fang et al., 2009). Hence, investigations of PAHs in sediments can provide useful information for further understanding of environmental processes and material transport. In this study, sixteen polycyclic aromatic hydrocarbons (PAHs) were extracted from a total of 112 surface sediment samples collected across the entire territory of the Bohai Sea. The detectable concentrations of PAHs ranged from 97.2 to 300.7 ng/g across all samples, indicating low contamination levels of PAHs compared with reported values for other coastal sediments in China and developed countries. The highest concentrations were found within three belts in the vicinity of Luan River Estuary-Qinhuangdao Harbor, the Cao River Estuary-Bohai Sea Center, and north of the Yellow River Estuary. The distribution patterns of PAHs and source identification implied that PAH contamination in the Bohai Sea mainly originates from offshore oil exploration, sewage discharge from rivers and shipping activities. Further Principal components analysis (PCA)/multivariate linear regression (MLR) analysis suggested that the contributions of spilled oil products (petrogenic), coal combustion and traffic-related pollution were 39, 38 and 23%, respectively. Pyrogenic sources (coal combustion and traffic-related pollution) contributed 61% of anthropogenic PAHs to sediments, which indicates that energy consumption is a predominant factor in PAH pollution in the Bohai Sea. Acknowledgements: This work was jointly supported by National Science Fund, China (Grant No.40806025), the State Oceanic Administration, China (Grant No. 201105003, 908-02-02-05, and GY02-2009G19). References Fang MD, Chang WK, Lee CL, Liu JT (2009) The use of polycyclic aromatic hydrocarbons as a particulate tracer in the water column Kaoping submarine canyon. J Mar Syst 76: 457-467.

  16. A three-step process to facilitate the annulation of polycyclic aromatic hydrocarbons.

    PubMed

    Martin, Sara E; Streeter, Matthew D; Jones, Laurel L; Klepfer, Matthew S; Atmatzidis, Kyriakos; Wille, Kristen D; Harrison, Sean A; Hoegg, Edward D; Sheridan, Heather M; Kramer, Stephanie; Parrish, Damon A; Amick, Aaron W

    2014-09-01

    A new efficient three-step process to annulate polycyclic aromatic hydrocarbons (PAHs) has been developed, providing access to PAHs with saturated rings that under current chemical methods would be difficult to produce in an efficient manner. This method relies on a palladium-catalyzed cross-coupling reaction of various brominated PAHs with cyclohexanone to yield α-arylated ketones, which are converted to regiospecific vinyl triflates and cyclized by a palladium-catalyzed intramolecular arene-vinyl triflate coupling to produce PAHs with incorporated saturated rings or "tetrahydroindeno-annulated" PAHs. PMID:25137354

  17. Role of Spin-Triplet Polycyclic Aromatic Hydrocarbons in Soot Surface Growth.

    PubMed

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

    2015-02-01

    Using density functional theory, a possible pathway of soot surface growth is studied in the low-temperature, postflame region in which spin-triplet polycyclic aromatic hydrocarbon (PAH) molecules with a small singlet-triplet energy gap react with unsaturated aliphatics such as acetylene via the carbon-addition-hydrogen-migration (CAHM) reaction. Results show that a PAH-core-aliphatic-shell structure is formed and the mass growth rate of this triplet soot surface growth reaction is one order of magnitude larger than that of the surface hydrogen-abstraction-carbon-addition (HACA) reaction at temperatures below 1500 K. PMID:26261966

  18. Evidence that Polycyclic Aromatic Hydrocarbons in Two Carbonaceous Chondrites Predate Parent-Body Formation

    NASA Technical Reports Server (NTRS)

    Plows, F. L.; Elsila, J. E.; Zare, R. N.; Buseck, P. R.

    2003-01-01

    Organic material in meteorites provides insight into the cosmochemistry of the early solar system. The distribution of polycyclic aromatic hydrocarbons (PAHs) in the Allende and Murchison carbonaceous chondrites was investigated using spatially resolved microprobe laser-desorption laser-ionization mass spectrometry. Sharp chemical gradients of PAHs are associated with specific meteorite features. The ratios of various PAH intensities relative to the smallest PAH, naphthalene, are nearly constant across the sample. These findings suggest a common origin for PAHs dating prior to or contemporary with the formation of the parent body, consistent with proposed interstellar formation mechanisms.

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

    NASA Astrophysics Data System (ADS)

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

    2007-09-01

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

  20. Molecular biology of environmental aromatic hydrocarbons. Progress report, January 1-June 31, 1981

    SciTech Connect

    Weiss, S.B.

    1981-07-01

    We have been examining the molecular biology of activated polycyclic aromatic hydrocarbons (PAH) in several different ways, using different biochemical systems. The projects involving these systems are as follows: (I) The binding of benzo(a)pyrene-7,8-dihydrodiol to phage DNA; (II) the binding of PAH-epoxide derivatives to single- and double-stranded 0X174 DNA and its effect on viral DNA infectivity; (III) the fate of benzo(a)pyrene adducts on SV40 DNA in infected monkey kidney cells; (IV) the effect of PAH derivatives on RNA transcription; and (V) the effects of anti-BPDE on tRNA aminoacyl charging and protein synthesis.

  1. Contamination of soils in the urbanized areas of Belarus with polycyclic aromatic hydrocarbons

    NASA Astrophysics Data System (ADS)

    Kukharchyk, T. I.; Khomich, V. S.; Kakareka, S. V.; Kurman, P. V.; Kozyrenko, M. I.

    2013-02-01

    The content of polycyclic aromatic hydrocarbons (PAHs) in the soils of urbanized areas, including the impact zones of Belarus, were studied. The concentrations of 16 PAHs in the soils were determined for individual and high-rise building zones, forests, and forest parks of Belarus. The levels of the PAH accumulation in the soils of different industrial enterprises and boiler stations were analyzed. Possible sources of soil contamination with PAHs were considered, and the structure of the PAHs in the soils was shown. The levels of the soil contamination were determined from the regulated parameters for individual compounds and the sum of 16 PAHs.

  2. Measurement of particulate phase polycyclic aromatic hydrocarbon (PAHs) around a petroleum refinery.

    PubMed

    Rao, Padma S; Ansari, M Faiyaz; Pipalatkar, P; Kumar, A; Nema, P; Devotta, S

    2008-02-01

    A study on concentrations of ambient particulates viz. total suspended particulate matters (TSP), respirable suspended particulate matter (RSPM) and polycyclic aromatic hydrocarbons (PAH) were carried out at six sites around the Asia's largest, 12 MMTPA, petroleum refinery in west coast of India. PAH concentrations are correlated with each other in these sites, suggesting that they have related sources and sinks. The present article discusses the monitoring aspects such as sample collection, pretreatment and analytical methods and compares the monitored levels for assessing the source receptor distribution pattern. The main sources of RSPM and PAHs in urban air are automobile exhaust (CPCB, Polycyclic aromatic hydrocarbons (PAHs) in air and their effects on human health. " http://www.cpcb.nic.in/ph/ch21103.htm ", 2003; Manuel et al., Environmental Science and Technology, 13: 227-231, 2004) and industrial emissions like petroleum refinery (Vo-Dinh, Chemical analysis of polycyclic aromatic hydrocarbons, Wiley: New York, 1989; Wagrowaski and Hites, Environmental Science and Technology, 31: 279-282, 1997). Polycyclic aromatic hydrocarbons (PAH) are ubiquitous constituents of urban airborne particulate mostly generated by anthropogenic activities (Li et al., Environmental Science and Technology, 37:1958-2965, 2003; Thorsen et al., Environmental Science and Technology, 38: 2029-2037, 2004; Ohura et al., Environmental Science and Technology, 32: 450-455, 2004) and some of them are of major health concern mainly due to their well-known carcinogenic and mutagenic properties (Soclo et al., Marine Pollution Bulletin, 40: 387-396, 2000; Chen et al., Environment International, 28: 659-668, 2003; Larsen and Baker, Environmental Science and Technology, 32: 450-455, 2003). Limited information is available on PAHs contributions from refineries to ambient air. Hence this study would not only create a database but also provide necessary inputs towards dose-response relationship for fixing standards. Also, since it acts as precursor to green house gas, the data would be useful for climate change assessments. The objective of this article is to find out the concentration of PAHs in particulate matter around petroleum refinery and compare with their concentrations in major Indian urban centers. PMID:17562207

  3. Determination of polyphenylarenes and polynuclear aromatic hydrocarbons by reversed phase HPLC

    SciTech Connect

    Spitzer, T.

    1987-01-01

    Standard mixtures of polycyclic compounds are analyzed by reversed phase microcapillary liquid chromatography. Acetonitrile/water and acetonitrile/THF/water are employed as stationary phases, and capacity ratios are reported. Polyphenylarenes can be distinguished from polynuclear aromatic hydrocarbons by a large shift in capacity ratios when changing the mobile phase. The shift in capacity ratios is most significant from 1,3,5-triphenylbenzene, which is demonstrated by a gradient elution. The influence of THF and water on retention behaviour of solutes is described.

  4. A DFT-based toxicity QSAR study of aromatic hydrocarbons to Vibrio fischeri: Consideration of aqueous freely dissolved concentration.

    PubMed

    Wang, Ying; Yang, Xianhai; Wang, Juying; Cong, Yi; Mu, Jingli; Jin, Fei

    2016-05-01

    In the present study, quantitative structure-activity relationship (QSAR) techniques based on toxicity mechanism and density functional theory (DFT) descriptors were adopted to develop predictive models for the toxicity of alkylated and parent aromatic hydrocarbons to Vibrio fischeri. The acute toxicity data of 17 aromatic hydrocarbons from both literature and our experimental results were used to construct QSAR models by partial least squares (PLS) analysis. With consideration of the toxicity process, the partition of aromatic hydrocarbons between water phase and lipid phase and their interaction with the target biomolecule, the optimal QSAR model was obtained by introducing aqueous freely dissolved concentration. The high statistical values of R(2) (0.956) and QCUM(2) (0.942) indicated that the model has good goodness-of-fit, robustness and internal predictive power. The average molecular polarizability (α) and several selected thermodynamic parameters reflecting the intermolecular interactions played important roles in the partition of aromatic hydrocarbons between the water phase and biomembrane. Energy of the highest occupied molecular orbital (EHOMO) was the most influential descriptor which dominated the toxicity of aromatic hydrocarbons through the electron-transfer reaction with biomolecules. The results demonstrated that the adoption of freely dissolved concentration instead of nominal concentration was a beneficial attempt for toxicity QSAR modeling of hydrophobic organic chemicals. PMID:26812082

  5. Effect of petroleum aromatic hydrocarbons on monogeneids parasitizing Atlantic cod, Gadus morhua L

    SciTech Connect

    Khan, R.A.; Kiceniuk, J.W.

    1988-07-01

    Fish gills appear to be more susceptible than other tissues to toxicants. The latter include petroleum aromatic hydrocarbons, which can induce lesions characterized by excessive mucus secretion, hyperplasia, fusion of secondary gill lamellae and capillary dilation. Fish are also natural hosts to several species of ectoparasites, especially monogeneans which live among the gill filaments. A previous study on the interrelation of water quality, gill parasites and gill pathology provided evidence that fish living in habitats degraded by pollutants such as Biscayne Bay, Florida, were heavily infested with monogeneids especially when gill lesions were severe. Atlantic cod, Gadus morhua, are hosts to monogeneans. The authors reported previously that crude oil fractions induced gill lesions in cod and also affected some gastrointestinal parasites. In the light of these reports, a study was undertaken to ascertain whether any relationship existed between gill lesions and gill parasites in cod following chronic exposure to petroleum hydrocarbons.

  6. Coating Polycyclic Aromatic Hydrocarbon Cations with Helium Clusters: Snowballs and Slush.

    PubMed

    Calvo, Florent

    2015-06-11

    The classical and quantum structures of cationic polycyclic aromatic hydrocarbon molecules (benzene, pyrene, coronene, and circumcoronene) coated by helium atoms have been theoretically investigated using a variety of computational methods. Classical shell filling, as determined from global optimization, is generally found to proceed by epitaxial additions on the graphitic surfaces before peripheral closure. From the quantum mechanical perspective provided by path-integral molecular dynamics simulations, vibrational delocalization is found to generally decrease the size of this first solvation shell, but also to give rise to a variety of situations in which the helium atoms are more or less localized depending on their environment, with strong finite size effects depending both on the hydrocarbon cation and the number of coating helium atoms. While the graphitic planes tend to bind helium sufficiently to give rise to snowball precursors, the peripheral regions are less dense and more delocalized, not as liquid as the outer layers but within an intermediate slushy character. PMID:25482143

  7. Distribution and sources of polycyclic aromatic hydrocarbons in Cilician Basin shelf sediments (NE Mediterranean).

    PubMed

    Kucuksezgin, Filiz; Pazi, Idil; Gonul, L Tolga; Duman, Muhammet

    2013-06-15

    This study corresponds to preliminary work representing an initial assessment for spatial distribution of polycyclic aromatic hydrocarbons (PAHs) in the Cilician Basin coastal sediments. The concentrations of PAHs in shelf sediments were determined from the three different regions of Cilician Basin (Eastern Mediterranean) in 2011. Concentrations of PAHs were low 5.43-271 ng g(-1) with respect to other coastal sediments in the Mediterranean and these results could be compared with concentrations found in open sea areas. PAH composed mainly of pyrolytic four and five-ring compounds. An abundance of high molecular weight PAHs indicated that atmospheric particles and urban aerosols are the major input route of hydrocarbons in the Cilician and Lattakia Basins. PAH levels were assessed in accordance with numerical Sediment Quality Guideline (SQG) of the USEPA. The results showed that no samples exceeded biological thresholds to pose biological impairments. PMID:23465576

  8. Distribution and fate of aliphatic and aromatic hydrocarbons in Antarctic fauna and environment

    NASA Astrophysics Data System (ADS)

    Platt, H. M.; Mackie, P. R.

    1980-03-01

    With the depletion of oil resources in more accessible areas, those of remote regions are being considered or indeed are now being exploited. In many of these regions, especially the polar ones, little is known of the effects such exploitation will have on the environment. But it is known that the ecosystems are often subject to great stress by natural climatic conditions and additional burdens imposed by man may have catastrophic environmental effects. South Georgia, a sub-Antarctic island, has a history of industrial activity mainly concerned with whaling operations that peaked around 1925-1935 but has since declined to virtually nothing. Studies of the ecology of the area provided a unique opportunity to assess the long-term effects that such activities had on the ecosystem. Off the whaling stations a considerable amount of waste material, including fuel oil, was released into the bays and inevitably some of this material was deposited in the sediments. Chemical evidence in the form of both paraffinic and aromatic hydrocarbons still persists in the sediments. The implications of this persistence in relation to the possible influence of the low temperature conditions are discussed. The superficial sediments, marine biota and terrestrial plants, which since 1965 have returned virtually to a pristine state, contain hydrocarbons essentially similar to unpolluted areas around the coast of Britain. Relatively high levels of carcinogenic/mutagenic polynuclear aromatic hydrocarbons in surface sediments suggests a world-wide background of abiogenic hydrocarbons probably disseminated by airborne transport. This appears to indicate that contamination reaches even remote parts of the world in relatively undiminished quantities.

  9. Chemical reactivity of aromatic hydrocarbons and operational degradation of organic light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Kondakov, Denis Y.; Brown, Christopher T.; Pawlik, Thomas D.; Jarikov, Viktor V.

    2010-01-01

    We report the study of the chemical reactivity of representative hydrocarbon organic light-emitting diode (OLED) materials—fully aromatic derivatives of anthracene and tetracene in the OLED environment. In addition to the participation in free-radical chemistry initiated by homolytic bond dissociation reactions of arylamines, the hydrocarbons appear to initiate and undergo dehydrogenation reactions following the electronic excitation caused by the recombination of charge carriers or by the absorption of a photon. A chemical product of the intramolecular dehydrogenation reaction, cyclization, was identified in photoexcited films of representative anthracene derivative and detected in electrically degraded OLEDs utilizing this material in the emissive layer. Other analogous intra- and intermolecular dehydrogenation reactions initiated by the excited states of hydrocarbons are also expected to occur in operating OLEDs. The stepwise transfers of hydrogen atoms or ions to neighboring molecules are likely to yield, at least in part, neutral or ionic forms of performance-damaging species—nonradiative recombination centers and luminescence quenchers. A comparison of the luminescence losses and quantities of the identified degradation product in OLEDs and photoexcited films suggests that the dehydrogenation mechanism plays a minor but not negligible part in the operational degradation of modern OLEDs utilizing hydrocarbons as emissive layer hosts.

  10. Formation of soot from polycyclic aromatic hydrocarbons as well as fullerenes and carbon nanotubes in the combustion of hydrocarbon

    NASA Astrophysics Data System (ADS)

    Mansurov, Z. A.

    2011-01-01

    The eightieth anniversary of Academician, Lenin Prize Winner Rem Ivanovich Soloukhin is an important event for the scientific association of investigators of combustion and detonation processes. R. I. Soloukhin has developed original gasdynamic laser systems based on the selective thermal excitation and mixing in a supersonic flow: efficient high-power gas-flow lasers of convective type with electric excitation and chemical lasers initiated by an electron beam. He proposed methods of measuring the rapidly changing pressure, density, temperature, and other parameters of processes occurring in shock waves. Deputy Editor-in-Chief of the Journal "Fizika Goreniya Vzryva," Professor at Novosibirsk University R. I. Soloukhin trained a Pleiad of Doctors and Candidates of Sciences. His fundamental investigations form the basis for the development of new directions in the physics of combustion and explosion. In the present article, recent works on soot formation in the combustion of hydrocarbons are reviewed. The phenomenology, kinetics, and mechanism of soot formation, the influence of different factors on the formation of polycyclic aromatic hydrocarbons, fullerenes, carbon nanotubes, and soot, low-temperature cold-flame soot formation, the combustion in an electric field, and the paramagnetism of soot particles were considered from the environmental standpoint.

  11. Field evaluation of sampling and analysis for organic pollutants in indoor air. Project summary

    SciTech Connect

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

    1988-09-01

    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 (PAH), PAH derivatives, and nicotine in residential air.

  12. FIELD EVALUATION OF SAMPLING AND ANALYSIS FOR ORGANIC POLLUTANTS IN INDOOR AIR

    EPA Science Inventory

    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 (PAH), PAH derivatives, a...

  13. Identification and quantification of seven fused aromatic rings C26H14peri-condensed benzenoid polycyclic aromatic hydrocarbons in a complex mixture of polycyclic aromatic hydrocarbons from coal tar.

    PubMed

    Oña-Ruales, Jorge O; Ruiz-Morales, Yosadara; Wise, Stephen A

    2016-04-15

    A methodology for the characterization of groups of polycyclic aromatic hydrocarbons (PAHs) using a combination of normal phase liquid chromatography with ultraviolet-visible spectroscopy (NPLC/UV-vis) and gas chromatography with mass spectrometry (GC/MS) was used for the identification and quantification of seven fused aromatic rings C26H14peri-condensed benzenoid polycyclic aromatic hydrocarbons, PAHs, in standard reference material (SRM) 1597a, complex mixture of PAHs from coal tar. The NPLC/UV-vis isolated the fractions based on the number of aromatic carbons and the GC/MS allowed the identification and quantification of five of the nine C26H14 PAH isomers; naphtho[1,2,3,4-ghi]perylene, dibenzo[b,ghi]perylene, dibenzo[b,pqr]perylene, naphtho[8,1,2-bcd]perylene, and dibenzo[cd,lm]perylene using a retention time comparison with authentic reference standards. For the other four benzenoid isomers with no available reference standards the following two approaches were used. First, the annellation theory was used to achieve the potential identification of benzo[qr]naphtho[3,2,1,8-defg]chrysene, and second, the elution distribution in the GC fractions was used to support the potential identification of benzo[qr]naphtho[3,2,1,8-defg]chrysene and to reach the tentative identifications of dibenzo[a,ghi]perylene, naphtho[7,8,1,2,3-pqrst]pentaphene, and anthra[2,1,9,8-opqra]naphthacene. It is the first time that naphtho[1,2,3,4-ghi]perylene, dibenzo[b,ghi]perylene, dibenzo[b,pqr]perylene, naphtho[8,1,2-bcd]perylene, and dibenzo[cd,lm]perylene are quantified, and the first time that benzo[qr]naphtho[3,2,1,8-defg]chrysene is potentially identified, in any sample, in any context. PMID:26976350

  14. Regression models to estimate the total concentration of polycyclic aromatic hydrocarbon metabolites in urine.

    PubMed

    Jain, Ram B

    2016-03-01

    Polycyclic aromatic hydrocarbons (PAH) are potentially mutagenic and carcinogenic and as such their exposure is of serious concern. Regression models to estimate the total concentration of polycyclic aromatic hydrocarbon metabolites (?PAH) in urine were developed. Using data from National Health and Nutrition Examination Survey for the years 2003-2008 and 2011-2012, regression models were developed to estimate ?PAH in urine. The performance of the fitted models were computed by comparing percent predicted values located between 0 and 5%, 5-10%, 15-20% and >20% of the observed values. While data for 2003-2008 were used to fit the regression models, the data for 2011-2012 were solely used to evaluate the performance of the fitted models. R(2) of the fitted model was 94.7%. About 46% of the predicted values for the 2003-2008 data and over 48% of the predicted values for the 2011-2012 data were found to be between 0 and 10% of the observed values. In order to use these models, in addition to age, gender, and smoking status, and optionally race/ethnicity, the knowledge of the levels of only 1-hydroxynaphthalene, 2-hydroxynaphthalene, and 9-hydroxyfluorene is necessary. Models that optionally require the knowledge of the levels of urine creatinine were also developed. PMID:26735733

  15. Questioning the existence of superconducting potassium doped phases for aromatic hydrocarbons

    NASA Astrophysics Data System (ADS)

    Heguri, Satoshi; Kobayashi, Mototada; Tanigaki, Katsumi

    2015-07-01

    Superconductivity in aromatic hydrocarbons doped with potassium (K) such as K3 [picene (PCN)] and K3 [phenanthrene (PHN)] is found for only armchair-type polycyclic aromatic hydrocarbon. In this paper the thermodynamics of the reaction processes of PHN or anthracene (AN, zigzag type) with K was studied using differential scanning calorimetry and x-ray diffraction. We show that PHN decomposes during the reaction, triggered by hydrogen abstraction, to give metal hydride KH and unknown amorphous. No stable doped phases exist in Kx(PHN ) with stoichiometries of x =1 -3 . However, in the case of AN, a stable doped phase forms. We claim that PHN, which has been reported to be energetically more stable in the ground state than AN by first principle calculations, is unstable upon doping. We also suggest that the superconductivity in K3(PCN ) is due to the misinterpretation of experimental data, which actually arises from ferromagnetic impurities. We have never detected the superconductivity above 2 K in these compounds. The superconductivity in both Kx(PHN ) and Kx(PCN ) is concluded to be highly questionable.

  16. Sequential accelerated solvent extraction of polycyclic aromatic hydrocarbons with different solvents: performance and implication.

    PubMed

    Ma, Xiaoxuan; Ran, Yong; Gong, Jian; Chen, Diyun

    2010-01-01

    Sixteen USEPA priority polycyclic aromatic hydrocarbons (PAHs) extracted by Soxhlet extraction (S-PAHs) with dichloromethane and routine accelerated solvent extraction (A-PAHs) with 1:1 toluene/methanol, respectively, were investigated in 24 soil samples from two cities in the center of the Pearl River Delta, South China. Polycyclic aromatic hydrocarbons, methylphenanthrene and perylene, in two soils, two sediments, and an immature oil shale were also sequentially extracted by accelerated solvent extraction (ASE) with each of four different organic solvents for three times. The A-PAHs' concentrations are 2.41 times the S-PAHs' concentrations. For sequential three ASEs, PAHs in the first extract account for 56 to 67% of their total concentrations in the sequential three extractions and toluene displays the best extraction performance among the four solvents. Diagnostic ratios of PAHs in Soxhlet extraction, routine ASE, and sequential ASE with each solvent for a given sample are very similar, suggesting their identical petrogenic and pyrogenic sources in the soils and sediments. But the PAH ratios for the shale have an obvious petrogenic origin. The perylene/5-ring PAH ratios indicate a diagenetic source, especially in the shale and sediments. The correlation analysis shows that A-PAHs/S-PAHs is better associated with the contents of total organic carbon (TOC) than those of black carbon (BC). The above results indicate the significant petrogenic origin of PAHs and the important effect of organic matter on their extraction and distribution in the investigated field soils/sediments. PMID:21284305

  17. Fate of Soil Organic Carbon and Polycyclic Aromatic Hydrocarbons in a Vineyard Soil Treated with Biochar.

    PubMed

    Rombolà, Alessandro G; Meredith, Will; Snape, Colin E; Baronti, Silvia; Genesio, Lorenzo; Vaccari, Francesco Primo; Miglietta, Franco; Fabbri, Daniele

    2015-09-15

    The effect of biochar addition on the levels of black carbon (BC) and polcyclic aromatic hydrocarbons (PAHs) in a vineyard soil in central Italy was investigated within a two year period. Hydropyrolysis (HyPy) was used to determine the contents of BC (BCHyPy) in the amended and control soils, while the hydrocarbon composition of the semi-labile (non-BCHyPy) fraction released by HyPy was determined by gas chromatography-mass spectrometry, together with the solvent-extractable PAHs. The concentrations of these three polycyclic aromatic carbon reservoirs changed and impacted differently the soil organic carbon over the period of the trial. The addition of biochar (33 ton dry biochar ha(-1)) gave rise to a sharp increase in soil organic carbon, which could be accounted for by an increase in BCHyPy. Over time, the concentration of BCHyPy decreased significantly from 36 to 23 mg g(-1) and as a carbon percentage from 79% to 61%. No clear time trends were observed for the non-BCHyPy PAHs varying from 39 to 34 μg g(-1) in treated soils, not significantly different from control soils. However, the concentrations of extractable PAHs increased markedly in the amended soils and decreased with time from 153 to 78 ng g(-1) remaining always higher than those in untreated soil. The extent of the BCHyPy loss was more compatible with physical rather than chemical processes. PMID:26263378

  18. [Temporal distribution, sources, and risk assessment of polycyclic aromatic hydrocarbons in sediment core from Miyun reservoir].

    PubMed

    Guo, Jian-yang; Liao, Hai-qing; Han, Mei; Li, Wen; Zhang, Run-yu; Wang, Jing; Wu, Feng-chang

    2010-03-01

    The temporal distribution of polycyclic aromatic hydrocarbons (PAHs) was measured in sediment core from Miyun reservoir, and the possible sources and the potential risk assessment also have been identified. The aim of the present work is to understand the temporal trend of PAHs in Miyun reservoir recently. The concentrations of sigma PAH16 in sediment ranged from 618.5 ng/g to 1087.9 ng/g, and roughly, increased continuously from the bottom (16 cm under the surface) to the surface sediment. The PAHs in sediment core were mainly composed of phenanthrene and fluorene. The concentrations of phenanthrene and fluorene in sediment core were 236.1-417.9 ng/g and 91-130.8 ng/g, respectively. Both of them accounted for 47.2%-58.1% of the sigma PAH16 in sediments. Nevertheless, high-rings aromatic hydrocarbons (5-6 rings) were increased steadily in recent years. PAHs compositional profile indicated that the main source of PAHs was originated from the combustion of coal and biomass. However, the vertical profiles of Flu/Flu + Pyr and INP/INP + BghiP ratios suggested that the vehicles emission was increased very recently. Risk assessment suggested that PAHs in sediment from Miyun reservoir was no significant biological impairment, and low toxicological risk of PAHs was found up to now. PMID:20358818

  19. Chemistry of polycyclic aromatic hydrocarbons formation from phenyl radical pyrolysis and reaction of phenyl and acetylene.

    PubMed

    Comandini, A; Malewicki, T; Brezinsky, K

    2012-03-15

    An experimental investigation of phenyl radical pyrolysis and the phenyl radical + acetylene reaction has been performed to clarify the role of different reaction mechanisms involved in the formation and growth of polycyclic aromatic hydrocarbons (PAHs) serving as precursors for soot formation. Experiments were conducted using GC/GC-MS diagnostics coupled to the high-pressure single-pulse shock tube present at the University of Illinois at Chicago. For the first time, comprehensive speciation of the major stable products, including small hydrocarbons and large PAH intermediates, was obtained over a wide range of pressures (25-60 atm) and temperatures (900-1800 K) which encompass the typical conditions in modern combustion devices. The experimental results were used to validate a comprehensive chemical kinetic model which provides relevant information on the chemistry associated with the formation of PAH compounds. In particular, the modeling results indicate that the o-benzyne chemistry is a key factor in the formation of multi-ring intermediates in phenyl radical pyrolysis. On the other hand, the PAHs from the phenyl + acetylene reaction are formed mainly through recombination between single-ring aromatics and through the hydrogen abstraction/acetylene addition mechanism. Polymerization is the common dominant process at high temperature conditions. PMID:22339468

  20. Semivolatile and particulate polycyclic aromatic hydrocarbons in environmental tobacco smoke. Cleanup, speciation, and emission factors

    SciTech Connect

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

    1995-06-01

    Studies of phase distributions and emission factors for polycyclic aromatic hydrocarbons (PAH) in environmental tobacco smoke (ETS) require collection and analysis of very small samples. To achieve the necessary selectivity and sensitivity, a method has been devised and tested for extraction and cleanup of gas- and particulate-phase ETS samples. Gas-phase species were trapped by polymeric sorbents, and particles were trapped on filters. The samples were extracted with hot cyclohexane, concentrated, and passed through silica solid-phase extraction columns for cleanup. After solvent change, the PAH were determined by high-performance liquid chromatography with two programmed fluorescence detectors. PAH concentrations in 15-mg aliquots of National Institute of Standards and Technology Standard Reference Material (SRM) 1649 (urban dust/organics) agreed well with published values. Relative precision at the 95% confidence level was 8% for SRM 1649 and 20% for replicate samples (5-mg) of ETS particles. Emission factors have been measured for a range of gas- and particulate-phase polycyclic aromatic hydrocarbons in ETS. The emission factors per cigarette were 13.0 {+-} 0.5 mg of particulate matter, 11.2 + 0.9 {mu}g for gas-phase napthalene, and 74 {+-} 10 ng for particulate benzo[a]pyrene. 21 refs., 5 figs., 7 tabs.

  1. Brine-induced advection of dissolved aromatic hydrocarbons to arctic bottom waters

    SciTech Connect

    Payne, J.R. ); Hachmeister, L.E. ); McNabb, G.D. Jr. ); Smith, G.S. ); Manen, C.A. ); Sharpe, H.E.

    1991-05-01

    Extruded brine, generated during sea ice formation in nearshore arctic waters, will sink to the bottom and can form a stable bottom boundary layer. This layer can persist for periods of up to 4-6 months. Limited quantities of dissolved aromatic hydrocarbons resulting from a spill of crude oil or refined petroleum distillate products during periods of ice growth can be transported as conservative components to the benthos with sinking brine. Once incorporated into the stable bottom boundary layer, these aromatic components are no longer subject to loss by evaporative processes, and they only can be diluted by ultimately mixing with uncontaminated water masses, a process that proceeds slowly throughout the ice-covered period. This mechanism for the transport of dissolved hydrocarbons has been demonstrated through a laboratory test-tank simulation and a chemical/physical oceanographic field program conducted in the Chukchi Sea near Pt. Frankline, AK (March 1985). The results are pertinent to shallow nearshore oil and gas exploration, development, production, and transportation activities in high latitude marine systems.

  2. Polycyclic aromatic hydrocarbon exhaust emissions from different reformulated diesel fuels and engine operating conditions

    NASA Astrophysics Data System (ADS)

    Borrás, Esther; Tortajada-Genaro, Luis A.; Vázquez, Monica; Zielinska, Barbara

    2009-12-01

    The study of light-duty diesel engine exhaust emissions is important due to their impact on atmospheric chemistry and air pollution. In this study, both the gas and the particulate phase of fuel exhaust were analyzed to investigate the effects of diesel reformulation and engine operating parameters. The research was focused on polycyclic aromatic hydrocarbon (PAH) compounds on particulate phase due to their high toxicity. These were analyzed using a gas chromatography-mass spectrometry (GC-MS) methodology. Although PAH profiles changed for diesel fuels with low-sulfur content and different percentages of aromatic hydrocarbons (5-25%), no significant differences for total PAH concentrations were detected. However, rape oil methyl ester biodiesel showed a greater number of PAH compounds, but in lower concentrations (close to 50%) than the reformulated diesel fuels. In addition, four engine operating conditions were evaluated, and the results showed that, during cold start, higher concentrations were observed for high molecular weight PAHs than during idling cycle and that the acceleration cycles provided higher concentrations than the steady-state conditions. Correlations between particulate PAHs and gas phase products were also observed. The emission of PAH compounds from the incomplete combustion of diesel fuel depended greatly on the source of the fuel and the driving patterns.

  3. Monohydroxylated polycyclic aromatic hydrocarbons influence spicule formation in the early development of sea urchins (Hemicentrotus pulcherrimus).

    PubMed

    Suzuki, Nobuo; Ogiso, Shouzo; Yachiguchi, Koji; Kawabe, Kimi; Makino, Fumiya; Toriba, Akira; Kiyomoto, Masato; Sekiguchi, Toshio; Tabuchi, Yoshiaki; Kondo, Takashi; Kitamura, Kei-ichiro; Hong, Chun-Sang; Srivastav, Ajai K; Oshima, Yuji; Hattori, Atsuhiko; Hayakawa, Kazuichi

    2015-05-01

    We previously demonstrated that monohydroxylated polycyclic aromatic hydrocarbons (OHPAHs), which are metabolites of polycyclic aromatic hydrocarbons (PAHs), act on calcified tissue and suppress osteoblastic and osteoclastic activity in the scales of teleost fish. The compounds may possibly influence other calcified tissues. Thus, the present study noted the calcified spicules in sea urchins and examined the effect of both PAHs and OHPAHs on spicule formation during the embryogenesis of sea urchins. After fertilization, benz[a]anthracene (BaA) and 4-hydroxybenz[a]anthracene (4-OHBaA) were added to seawater at concentrations of 10(-8) and 10(-7) M and kept at 18 °C. The influence of the compound was given at the time of the pluteus larva. At this stage, the length of the spicule was significantly suppressed by 4-OHBaA (10(-8) and 10(-7) M). BaA (10(-7) M) decreased the length of the spicule significantly, while the length did not change with BaA (10(-8) M). The expression of mRNAs (spicule matrix protein and transcription factors) in the 4-OHBaA (10(-7) M)-treated embryos was more strongly inhibited than were those in the BaA (10(-7) M)-treated embryos. This is the first study to demonstrate that OHPAHs suppress spicule formation in sea urchins. PMID:25737366

  4. Polycyclic aromatic hydrocarbon-DNA adducts and the CYP1A1 restriction fragment length polymorphism

    SciTech Connect

    Shields, P.G.; Bowman, E.D.; Weston, A.; Harris, C.C.; Sugimura, H.; Caporaso, N.E.; Petruzzelli, S.F. ); Trump, B.F. )

    1992-11-01

    Human cancer risk assessment at a genetic level involves the investigation of carcinogen metabolism and DNA adduct formation. Wide interindividual differences in metabolism result in different DNA adduct levels. For this and other reasons, many laboratories have considered DNA adducts to be a measure of the biologically effective dose of a carcinogen. Techniques for studying DNA adducts using chemically specific assays are becoming available. A modification of the [sup 32]P-postlabeling assay for polycyclic aromatic hydrocarbon DNA adducts described here provides potential improvements in quantification. DNA adducts, however, reflect only recent exposure to carcinogens; in contrast, genetic testing for metabolic capacity indicates the extent to which carcinogens can be activated and exert genotoxic effects. Such studies may reflect both separate and integrated risk factors together with DNA adduct levels. A recently described restriction fragment length polymorphism for the CYP1A1, which codes for the cytochrome P450 enzyme primarily responsible for the metabolic activation of carcinogenic polycyclic aromatic hydrocarbons, has been found to be associated with lung cancer risk in a Japanese population. In a subset of individuals enrolled in a US lung cancer case-control study, no association with lung cancer was found. 17 refs., 3 figs.

  5. Study of the adsorption of aromatic hydrocarbons by marine sediments. Final report

    SciTech Connect

    Henrichs, S.M.; Luoma, M.; Smith, S.

    1997-08-01

    Three aromatic hydrocarbons--benzene, naphthalene, and phenanthrene--were rapidly and strongly adsorbed by intertidal sediments from Jakolof Bay, lower Cook Inlet. Adsorption of phenanthrene was more than twice that of naphthalene and benzene. Adsorption was not completely, rapidly reversible by suspension of the sediment in clean seawater. Longer adsorption reaction times led to decreased desorption, except for benzene. All sites for adsorption on the sediment surface appeared to be equivalent, and availability of adsorption sites did not limit adsorption over the concentration range studied. Adsorption coefficients for phenanthrene varied among sediment samples by as much as a factor of 3. This variability was not correlated with sediment organic carbon content, indicating that organic matter was not solely responsible for the adsorption properties of these sediments. The bioavailability of phenanthrene was decreased by adsorption to sediment. Combined with the finding that adsorption is not completely reversible, these results indicate that adsorption could contribute to the persistence of aromatic hydrocarbons in lower Cook Inlet sediments.

  6. Petroleum alteration by thermochemical sulfate reduction - A comprehensive molecular study of aromatic hydrocarbons and polar compounds

    NASA Astrophysics Data System (ADS)

    Walters, Clifford C.; Wang, Frank C.; Qian, Kuangnan; Wu, Chunping; Mennito, Anthony S.; Wei, Zhibin

    2015-03-01

    Thermochemical sulfate reduction (TSR) alters petroleum composition as it proceeds towards the complete oxidation of hydrocarbons to CO2. The effects of TSR on the molecular and isotopic composition of volatile species are well known; however, the non-volatile higher molecular weight aromatic and polar species have not been well documented. To address this deficiency, a suite of onshore Gulf coast oils and condensates generated from and accumulating in Smackover carbonates was assembled to include samples that experienced varying levels of TSR alteration and in reservoir thermal cracking. The entire molecular composition of aromatic hydrocarbons and NSO species were characterized and semi-quantified using comprehensive GC × GC (FID and CSD) and APPI-FTICR-MS. The concentration of thiadiamondoids is a reliable indicator of the extent of TSR alteration. Once generated by TSR, thiadiamondoids remain thermally stable in all but the most extreme reservoir temperatures (>180 °C). Hydrocarbon concentrations and distributions are influenced by thermal cracking and TSR. With increasing TSR alteration, oils become enriched in monoaromatic hydrocarbons and the distribution of high molecular weight aromatic hydrocarbons shifts towards more condensed species with a decrease in the number of alkyl carbons. Organosulfur compounds are created by the TSR process. In addition to the increase in benzothiophenes and dibenzothiophenes noted in previous studies, TSR generates condensed species containing one or more sulfur atoms that likely are composed of a single or multiple thiophenic cores. We hypothesize that these species are generated from the partial oxidation of PAHs and dealkylation reactions, followed by sulfur incorporation and condensation reactions. The organosulfur species remaining in the TSR altered oils are "proto-solid bitumen" moieties that upon further condensation, oxidation or sulfur incorporation result in highly sulfur enriched solid bitumen, which is chemically distinct from pyrobitumen formed by thermal cracking reactions. Although TSR involves the oxidation of hydrocarbons to CO2, prior studies of TSR-altered oils have not identified intermediate products. Using NESI-FTIRC-MS, the presence and distribution of oxygenated species become evident. All oils possess minor amounts of O2 and O4 species, presumable mono- and di-naphthenic acids originating from the source. As TSR progresses, the distribution of oxygenated species shifts towards increasing species with higher oxygen content, up to O8. Similar trends are observed for the SOx species. We hypothesize that these are partially oxidized condensed hydrocarbons and that these species are likely formed by the reaction proposed by Püttmann et al. (1989) for the oxidation of PAHs associated with Kupferschiefer mineralization, whereby hydrocarbons with aryl-aryl bonds incorporate sulfur to form thiophenic species. The rate of TSR is influenced by reservoir temperature and the presence of H2S. Typically, high reservoir temperatures (>140 °C) are needed for extensive TSR alteration to occur. Oil from the Gin Creek Field appears to have received a charge of H2S, presumably from TSR alteration of a down dip reservoir, which has accelerated the TSR reaction within a relatively cold reservoir (∼109 °C). This condition has allowed for the generation and preservation of abundant sulfur containing species that would be thermally cracked at higher temperatures.

  7. Polycyclic aromatic hydrocarbons inhibit the activity of acetylcholinesterase purified from electric eel.

    PubMed

    Kang, J J; Fang, H W

    1997-09-18

    Polycyclic aromatic hydrocarbons (PAHs) are formed during the incomplete combustion of fossil fuels, wood and municipal waste incineration, from internal combustion engines, and from various food cooking operations and are common environmental contaminants which have been detected in surface waters, sediments, soils, plants, and both rural and urban air. In this study, we have shown that, for the first time, in vitro addition of PAHs dose-dependently inhibited the activity of acetylcholinesterase purified from electric eel in a competitive manner. The PAHs containing 3 or higher aromatic rings showed the highest inhibitory effect with the IC50 values between 2 and 6 ppm. Among the PAHs tested, chrysene and pyrene exhibit the highest and lowest potency with IC50 values of 2. 40+/-0.04 and 5.22+/-0.38 ppm, respectively. PAHs with lower number of aromatic rings, such as naphthalene, acenaphthylene and fluorene, and oxygenated PAHs, such as anthraquinone and xanthone, showed no or slight inhibition of the acetylcholinesterase activity. PMID:9299514

  8. Polycyclic aromatic hydrocarbon (PAH) formation from benzyl radicals: a reaction kinetics study.

    PubMed

    Sinha, Sourab; Raj, Abhijeet

    2016-03-01

    The role of resonantly stabilized radicals such as propargyl, cyclopentadienyl and benzyl in the formation of aromatic hydrocarbons such as benzene and naphthalene in the high temperature environments has been long known. In this work, the possibility of benzyl recombination to form three-ring aromatics, phenanthrene and anthracene, is explored. A reaction mechanism for it is developed, where reaction energetics are calculated using density functional theory (B3LYP functional with 6-311++G(d,p) basis set) and CBS-QB3, while temperature-dependent reaction kinetics are evaluated using transition state theory. The mechanism begins with barrierless formation of bibenzyl from two benzyl radicals with the release of 283.2 kJ mol(-1) of reaction energy. The further reactions involve H-abstraction by a H atom, H-desorption, H-migration, and ring closure to gain aromaticity. Through mechanism and rate of production analyses, the important reactions leading to phenanthrene and anthracene formation are determined. Phenanthrene is found to be the major product at high temperatures. Premixed laminar flame simulations are carried out by including the proposed reactions for phenanthrene formation from benzyl radicals and compared to experimentally observed species profiles to understand their effects on species concentrations. PMID:26923612

  9. Aliphatic and aromatic hydrocarbons in different sized aerosols over the Mediterranean Sea: Occurrence and origin

    NASA Astrophysics Data System (ADS)

    Sicre, M. A.; Marty, J. C.; Saliot, A.; Aparicio, X.; Grimalt, J.; Albaiges, J.

    Marine aerosols were collected using a five-stage cascade impactor during the PHYCEMED II cruise in the Western Mediterranean Sea (October 1983). Their composition in aliphatic and aromatic hydrocarbons (HCs) was analyzed, representing the first time that concentrations of polynuclear aromatic HCs (PAH) are reported in relation to particle size for aerosols of remote marine areas. The HC concentrations were found to be dependent on the origin of the air masses. They were higher for air coming from North European countries than for air originating in the Atlantic and the South of Spain. The concentrations range between 7 and 14 ng m -3for n-alkanes and between 0.2 and 0.4 ng m -3for total PAH. Based on molecular criteria, several sources for these HCs have been identified: continental higher plant waxes, petroleum and pyrolysis (namely coal combustion and vehicular exhausts). Mass medium equivalent diameters (MMED) for the naturally derived n-alkanes are in the 1.79-2.53 μm range, indicating an origin related with the emission of large particles from higher plant waxes or from soil dusts. In contrast, MMED for the anthropogenic HCs, both aliphatic and aromatic, are smaller than the micron, suggesting initial emission of PAH through pyrolytic processes in the vapor phase followed by condensation onto larger sub-μm particles.

  10. Aromatic hydrocarbons, diamonds, and fullerenes in interstellar space: puzzles to be solved by laboratory and theoretical astrochemistry.

    PubMed

    Sellgren, K

    2001-03-15

    New research is presented, and previous research is reviewed, on the emission and absorption of interstellar aromatic hydrocarbons. Emission from aromatic hydrocarbons dominates the mid-infrared emission of many galaxies, including our own Milky Way galaxy. Only recently have aromatic hydrocarbons been observed in absorption in the interstellar medium, along lines of sight with high column densities of interstellar gas and dust. Much work on interstellar aromatics has been carried out, with astronomical observations and laboratory and theoretical astrochemistry. In many cases, the predictions of laboratory and theoretical work are confirmed by astronomical observations but, in other cases, clear discrepancies exist that provide problems to be solved by a combination of astronomical observations, laboratory studies, and theoretical studies. The emphasis of this paper will be on current outstanding puzzles concerning aromatic hydrocarbons that require further laboratory and theoretical astrochemistry to resolve. This paper will also touch on related topics where laboratory and theoretical astrochemistry studies are needed to explain astrophysical observations, such as a possible absorption feature due to interstellar 'diamonds' and the search for fullerenes in space. PMID:11345243

  11. Determination of C6-C10 aromatic hydrocarbons in water by purge-and-trap capillary gas chromatography

    USGS Publications Warehouse

    Eganhouse, R.P.; Dorsey, T.F.; Phinney, C.S.; Westcott, A.M.

    1993-01-01

    A method is described for the determination of the C6-C10 aromatic hydrocarbons in water based on purge-and-trap capillary gas chromatography with flame ionization and mass spectrometric detection. Retention time data and 70 eV mass spectra were obtained for benzene and all 35 C7-C10 aromatic hydrocarbons. With optimized chromatographic conditions and mass spectrometric detection, benzene and 33 of the 35 alkylbenzenes can be identified and measured in a 45-min run. Use of a flame ionization detector permits the simultaneous determination of benzene and 26 alkylbenzenes.

  12. Analysis of the impregnation of ZnO:Mn2+ nanoparticles on cigarette filters for trapping polycyclic aromatic hydrocarbons (PAHs)

    NASA Astrophysics Data System (ADS)

    Estrada-Izquierdo, Irma; Sánchez-Espindola, Esther; Uribe-Hernández, Raúl; Ramón-Gallegos, Eva

    2012-10-01

    Each cigarette can generate 1149 ng of a mixture of 14 polycyclic aromatic hydrocarbons, of which there are a lot of information about its harmful effects on the environment and human health, they are considered mutagenic, teratogenic and carcinogenic. In this paper we tested ZnO:Mn2+ nanoparticles, attached to the filters of cigarettes. The first results showed that the filtration system was able to catch the Benzo(a)pyrene contained in cigarette smoke; but more tests are needed to quantify the efficiency with greater accuracy over other polycyclic aromatic hydrocarbons.

  13. Glutathione S-transferase-encoding gene as a potential probe for environmental bacterial isolates capable of degrading polycyclic aromatic hydrocarbons.

    PubMed Central

    Lloyd-Jones, G; Lau, P C

    1997-01-01

    Homologs of the glutathione S-transferase (GST)-encoding gene were identified in a collection of aromatic hydrocarbon-degrading Sphingomonas spp. isolated from New Zealand, Antarctica, and the United States by using PCR primers designed from the GST-encoding gene of Sphingomonas paucimobilis EPA505. Sequence analysis of PCR fragments generated from these isolates and of the GST gene amplified from DNA extracted from polycyclic aromatic hydrocarbon (PAH)-contaminated soil revealed a high degree of conservation, which may make the GST-encoding gene a potentially useful marker for PAH-degrading bacteria. PMID:9251217

  14. Biodegradation of polycyclic aromatic hydrocarbons by Trichoderma species: a mini review.

    PubMed

    Zafra, German; Cortés-Espinosa, Diana V

    2015-12-01

    Fungi belonging to Trichoderma genus are ascomycetes found in soils worldwide. Trichoderma has been studied in relation to diverse biotechnological applications and are known as successful colonizers of their common habitats. Members of this genus have been well described as effective biocontrol organisms through the production of secondary metabolites with potential applications as new antibiotics. Even though members of Trichoderma are commonly used for the commercial production of lytic enzymes, as a biological control agent, and also in the food industry, their use in xenobiotic biodegradation is limited. Trichoderma stands out as a genus with a great range of substrate utilization, a high production of antimicrobial compounds, and its ability for environmental opportunism. In this review, we focused on the recent advances in the research of Trichoderma species as potent and efficient aromatic hydrocarbon-degrading organisms, as well as aimed to provide insight into its potential role in the bioremediation of soils contaminated with heavy hydrocarbons. Several Trichoderma species are associated with the ability to metabolize a variety of both high and low molecular weight polycyclic aromatic hydrocarbons (PAHs) such as naphthalene, phenanthrene, chrysene, pyrene, and benzo[a]pyrene. PAH-degrading species include Trichoderma hamatum, Trichoderma harzianum, Trichoderma reesei, Trichoderma koningii, Trichoderma viride, Trichoderma virens, and Trichoderma asperellum using alternate enzyme systems commonly seen in other organisms, such as multicooper laccases, peroxidases, and ring-cleavage dioxygenases. Within these species, T. asperellum stands out as a versatile organism with remarkable degrading abilities, high tolerance, and a remarkable potential to be used as a remediation agent in polluted soils. PMID:26498812

  15. Polycyclic aromatic hydrocarbon exposure in household air pollution from solid fuel combustion among the female population of Xuanwei and Fuyuan counties, China.

    PubMed

    Downward, George S; Hu, Wei; Rothman, Nat; Reiss, Boris; Wu, Guoping; Wei, Fusheng; Chapman, Robert S; Portengen, Lutzen; Qing, Lan; Vermeulen, Roel

    2014-12-16

    Exposure to polycyclic aromatic hydrocarbons (PAHs) from burning "smoky" (bituminous) coal has been implicated as a cause of the high lung cancer incidence in the counties of Xuanwei and Fuyuan, China. Little is known about variations in PAH exposure from throughout the region nor how fuel source and stove design affects exposure. Indoor and personal PAH exposure resulting from solid fuel combustion in Xuanwei and Fuyuan was investigated using repeated 24 h particle bound and gas-phase PAH measurements, which were collected from 163 female residents of Xuanwei and Fuyuan. 549 particle bound (283 indoor and 266 personal) and 193 gas phase (all personal) PAH measurements were collected. Mixed effect models indicated that PAH exposure was up to 6 times higher when burning smoky coal than smokeless coal and varied by up to a factor of 3 between different smoky coal geographic sources. PAH measurements from unventilated firepits were up to 5 times that of ventilated stoves. Exposure also varied between different room sizes and season of measurement. These findings indicate that PAH exposure is modulated by a variety of factors, including fuel type, coal source, and stove design. These findings may provide valuable insight into potential causes of lung cancer in the area. PMID:25393345

  16. Polycyclic Aromatic Hydrocarbon Exposure in Household Air Pollution from Solid Fuel Combustion among the Female Population of Xuanwei and Fuyuan Counties, China

    PubMed Central

    2015-01-01

    Exposure to polycyclic aromatic hydrocarbons (PAHs) from burning “smoky” (bituminous) coal has been implicated as a cause of the high lung cancer incidence in the counties of Xuanwei and Fuyuan, China. Little is known about variations in PAH exposure from throughout the region nor how fuel source and stove design affects exposure. Indoor and personal PAH exposure resulting from solid fuel combustion in Xuanwei and Fuyuan was investigated using repeated 24 h particle bound and gas-phase PAH measurements, which were collected from 163 female residents of Xuanwei and Fuyuan. 549 particle bound (283 indoor and 266 personal) and 193 gas phase (all personal) PAH measurements were collected. Mixed effect models indicated that PAH exposure was up to 6 times higher when burning smoky coal than smokeless coal and varied by up to a factor of 3 between different smoky coal geographic sources. PAH measurements from unventilated firepits were up to 5 times that of ventilated stoves. Exposure also varied between different room sizes and season of measurement. These findings indicate that PAH exposure is modulated by a variety of factors, including fuel type, coal source, and stove design. These findings may provide valuable insight into potential causes of lung cancer in the area. PMID:25393345

  17. Aliphatic and polycyclic aromatic hydrocarbons in Gulf of Trieste sediments (northern Adriatic): potential impacts of maritime traffic.

    PubMed

    Bajt, Oliver

    2014-09-01

    The Gulf of Trieste (northern Adriatic) is one of the most urbanized and industrialized areas in the northern Adriatic, with intense maritime traffic experienced at multiple ports. The impact of maritime traffic on contamination by hydrocarbons in this area was assessed. Concentrations of hydrocarbons were higher near the expected contamination sources and still elevated in the adjacent offshore areas. Aliphatic hydrocarbons were mainly of petrogenic origin, with some contribution of biogenic origin. A continuous contamination by aliphatic hydrocarbons and degradation processes were hypothesized. Concentrations of total polycyclic aromatic hydrocarbons (PAH) were generally greater near the contamination sources. Compared to the prevailing pyrolytic origin, the petrogenic PAH origin seemed to be less important, but not negligible. Results revealed that intensive maritime traffic is a probable source of contamination by hydrocarbons in the investigated area, which is largely limited to areas near the contamination sources. PMID:24997612

  18. Polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and chlorinated pesticides in background air in central Europe - investigating parameters affecting wet scavenging of polycyclic aromatic hydrocarbons

    NASA Astrophysics Data System (ADS)

    Shahpoury, P.; Lammel, G.; Holubová Šmejkalová, A.; Klánová, J.; Přibylová, P.; Váňa, M.

    2014-10-01

    Concentrations of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and chlorinated pesticides (CPs) were measured in air and precipitation at a background site in central Europe. Σ PAH concentrations in air and rainwater ranged from 0.7 to 327.9 ng m-3 and below analytical method detection limit (< MDL) to 2.1 × 103 ng L-1. The concentrations of PCBs and CPs in rainwater were < MDL. Σ PCB and Σ CP concentrations in air ranged from < MDL to 44.6 and < MDL to 351.7 pg m-3, respectively. The potential relationships between PAH wet scavenging and particulate matter and rainwater properties were investigated. The concentrations of ionic species in particulate matter and rainwater were significantly correlated, highlighting the importance of particle scavenging process. Overall, higher scavenging efficiencies were found for relatively less volatile PAHs, underlining the effect of analyte gas-particle partitioning on scavenging process. The PAH wet scavenging was more effective when the concentrations of ionic species were high. In addition, the elemental and organic carbon contents of the particulate matter were found to influence the PAH scavenging.

  19. Polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and chlorinated pesticides in background air in central Europe - investigating parameters affecting wet scavenging of polycyclic aromatic hydrocarbons

    NASA Astrophysics Data System (ADS)

    Shahpoury, P.; Lammel, G.; Holubová Šmejkalová, A.; Klánová, J.; Přibylová, P.; Váňa, M.

    2015-02-01

    Concentrations of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and chlorinated pesticides (CPs) were measured in air and precipitation at a background site in central Europe. ∑ PAH concentrations in air and rainwater ranged from 0.7 to 327.9 ng m-3 and below limit of quantification (< LOQ) to 2.1 × 103 ng L-1. The concentrations of PCBs and CPs in rainwater were < LOQ. ∑ PCB and ∑ CP concentrations in air ranged from < LOQ to 44.6 and < LOQ to 351.7 pg m-3, respectively. The potential relationships between PAH wet scavenging and particulate matter and rainwater properties were investigated. The concentrations of ionic species in particulate matter and rainwater were significantly correlated, highlighting the importance of particle scavenging process. Overall, higher scavenging efficiencies were found for relatively less volatile PAHs, underlining the effect of analyte gas-particle partitioning on scavenging process. The particulate matter removal by rain, and consequently PAH wet scavenging, was more effective when the concentrations of ionic species were high. In addition, the elemental and organic carbon contents of the particulate matter were found to influence the PAH scavenging.

  20. THE EFFECT OF ROUTE OF ADMINISTRATION OF POLYCYCLIC AROMATIC HYDROCARBONS ON DNA ADDUCTION AND CYTOGENETIC DAMAGE IN PERIPHERAL BLOOD LYMPHOCYTES OF MICE AND RATS

    EPA Science Inventory

    The effect of route of administration of polycyclic aromatic hydrocarbons on DNA adduction and cytogenetic damage in peripheral blood lymphocytes of mice and rats

    Experiments were designed to investigate how the route of exposure to polycyclic
    aromatic hydrocarbons (PA...