Occupational PAH exposures during prescribed pile burns.

PubMed

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

2008-08-01

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

Occupational PAH Exposures during Prescribed Pile Burns

PubMed Central

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

2008-01-01

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

Laboratory Astrochemistry: Interstellar PAH Analogs

NASA Technical Reports Server (NTRS)

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

2000-01-01

Polycyclic aromatic hydrocarbons (PAHs) are now considered to be an important and ubiquitous component of the organic material in space. PAHs are found in a large variety of extraterrestrial materials such as interplanetary dust particles (IDPs) and meteoritic materials. PAHs are also good candidates to account for the infrared emission bands (UIRs) and the diffuse interstellar optical absorption bands (DIBs) detected in various regions of the interstellar medium. The recent observations made with the Infrared Space Observatory (ISO) have confirmed the ubiquitous nature of the UIR bands and their carriers. PAHs are though to form through chemical reactions in the outflow from carbon-rich stars in a process similar to soot formation. Once injected in the interstellar medium, PAHs are further processed by the interstellar radiation field, interstellar shocks and energetic particles. A major, dedicated, laboratory effort has been undertaken over the past years to measure the physical and chemical characteristics of these complex molecules and their ions under experimental conditions that mimic the interstellar conditions. These measurements require collision-free conditions where the molecules and ions are cold and chemically isolated. The spectroscopy of PAHs under controlled conditions represents an essential diagnostic tool to study the evolution of extraterrestrial PAHs. The Astrochemistry Laboratory program will be discussed through its multiple aspects: objectives, approach and techniques adopted, adaptability to the nature of the problem(s), results and implications for astronomy as well as for molecular spectroscopy. A review of the data generated through laboratory simulations of space environments and the role these data have played in our current understanding of the properties of interstellar PAHs will be presented. The discussion will also introduce the newest generation of laboratory experiments that are currently being developed in order to provide a

Pavement Sealcoat, PAHs, and the Environment

NASA Astrophysics Data System (ADS)

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

2011-12-01

Recent research by the USGS has identified coal-tar-based pavement sealants as a major source of polycyclic aromatic hydrocarbons (PAHs) to the environment. Coal-tar-based sealcoat is commonly used to coat parking lots and driveways and is typically is 20-35 percent coal tar pitch, a known human carcinogen. Several PAHs are suspected mutagens, carcinogens, and (or) teratogens. In the central and eastern U.S. where the coal-tar-based sealants dominate use, sum-PAH concentration in dust particles from sealcoated pavement is about 1,000 times higher than in the western U.S. where the asphalt-based formulation is prevalent. Source apportionment modeling indicates that particles from sealcoated pavement are contributing the majority of the PAHs to recent lake sediment in 35 U.S. urban lakes and are the primary cause of upward trends in PAHs in many of these lakes. Mobile particles from parking lots with coal-tar-based sealcoat are tracked indoors, resulting in elevated PAH concentrations in house dust. In a recently completed study, volatilization fluxes of PAHs from sealcoated pavement were estimated to be about 60 times fluxes from unsealed pavement. Using a wide variety of methods, the author and colleagues have shown that coal-tar-based sealcoat is a major source of PAHs to the urban environment and might pose risks to aquatic life and human health.

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

NASA Astrophysics Data System (ADS)

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

2015-04-01

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

Performance of PAHs emission from bituminous coal combustion.

PubMed

Yan, Jian-Hua; You, Xiao-Fang; Li, Xiao-Dong; Ni, Ming-Jiang; Yin, Xue-Feng; Cen, Ke-Fa

2004-12-01

Carcinogenic and mutagenic polycyclic aromatic hydrocarbons (PAHs) generated in coal combustion have caused great environmental health concern. Seventeen PAHs (16 high priority PAHs recommended by USEPA plus Benzo[e]pyrene) present in five raw bituminous coals and released during bituminous coal combustion were studied. The effects of combustion temperature, gas atmosphere, and chlorine content of raw coal on PAHs formation were investigated. Two additives (copper and cupric oxide) were added when the coal was burned. The results indicated that significant quantities of PAHs were produced from incomplete combustion of coal pyrolysis products at high temperature, and that temperature is an important causative factor of PAHs formation. PAHs concentrations decrease with the increase of chlorine content in oxygen or in nitrogen atmosphere. Copper and cupric oxide additives can promote PAHs formation (especially the multi-ring PAHs) during coal combustion.

Urban sprawl leaves its PAH signature

USGS Publications Warehouse

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

2000-01-01

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

Do 16 Polycyclic Aromatic Hydrocarbons Represent PAH Air Toxicity?

PubMed Central

Samburova, Vera; Zielinska, Barbara; Khlystov, Andrey

2017-01-01

Estimation of carcinogenic potency based on analysis of 16 polycyclic aromatic hydrocarbons (PAHs) ranked by U.S. Environmental Protection Agency (EPA) is the most popular approach within scientific and environmental air quality management communities. The majority of PAH monitoring projects have been focused on particle-bound PAHs, ignoring the contribution of gas-phase PAHs to the toxicity of PAH mixtures in air samples. In this study, we analyzed the results of 13 projects in which 88 PAHs in both gas and particle phases were collected from different sources (biomass burning, mining operation, and vehicle emissions), as well as in urban air. The aim was to investigate whether 16 particle-bound U.S. EPA priority PAHs adequately represented health risks of inhalation exposure to atmospheric PAH mixtures. PAH concentrations were converted to benzo(a)pyrene-equivalent (BaPeq) toxicity using the toxic equivalency factor (TEF) approach. TEFs of PAH compounds for which such data is not available were estimated using TEFs of close isomers. Total BaPeq toxicities (∑88BaPeq) of gas- and particle-phase PAHs were compared with BaPeq toxicities calculated for the 16 particle-phase EPA PAH (∑16EPABaPeq). The results showed that 16 EPA particle-bound PAHs underrepresented the carcinogenic potency on average by 85.6% relative to the total (gas and particle) BaPeq toxicity of 88 PAHs. Gas-phase PAHs, like methylnaphthalenes, may contribute up to 30% of ∑88BaPeq. Accounting for other individual non-EPA PAHs (i.e., benzo(e)pyrene) and gas-phase PAHs (i.e., naphthalene, 1- and 2-methylnaphthalene) will make the risk assessment of PAH-containing air samples significantly more accurate. PMID:29051449

Do 16 Polycyclic Aromatic Hydrocarbons Represent PAH Air Toxicity?

PubMed

Samburova, Vera; Zielinska, Barbara; Khlystov, Andrey

2017-08-15

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

PAH Spectroscopy: Past, Present and Future

NASA Technical Reports Server (NTRS)

Mattioda, Andrew

2016-01-01

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

Polycyclic aromatic hydrocarbons (PAHs) and their derivatives (oxygenated-PAHs, nitrated-PAHs and azaarenes) in size-fractionated particles emitted in an urban road tunnel

NASA Astrophysics Data System (ADS)

Alves, C. A.; Vicente, A. M. P.; Gomes, J.; Nunes, T.; Duarte, M.; Bandowe, B. A. M.

2016-11-01

A sampling campaign of size segregated particulate matter (PM0.5, PM0.5-1, PM1-2.5 and PM2.5-10) was carried out at two sites, one in a road tunnel (Braga, Portugal) and another at an urban background location in the neighbourhood. Particle-bound polycyclic aromatic compounds were extracted with organic solvents and analysed by gas chromatography-mass spectrometry. Twenty six parent and alkyl-polycyclic aromatic hydrocarbons (PAHs), 4 azaarenes (AZAs), 15 nitrated and 15 oxygenated derivatives (NPAHs and OPAHs) were analysed. On average, submicron particles (PM1) in the tunnel comprised 93, 91, 96 and 71% of the total PAHs, OPAHs, NPAHs and AZAs mass in PM10, respectively. Tunnel to outdoor PAH concentration ratios between 10 and 14 reveal the strong contribution of fresh exhaust emissions to the PM loads. The dominant PAHs in the tunnel were pyrene, retene and benzo[ghi]perylene, accounting for 20, 17 and 8% of the total PAH levels in PM10, respectively. Isomer ratios indicated the importance of unburnt fuel as a significant PAH source. The only NPAH consistently present in all samples was 5-nitroacenaphthene. Indanone and 1,8-naphthalic anhydride were the most abundant OPAHs, accounting for 25 and 17% of the total concentrations of this organic class, respectively. Other abundant OPAHs were 1,4-naphthoquinone, 9-fluorenone, 1,2-acenaphthylenequinone and 7H-benz[de]anthracene-7-one. Individual emission factors (μg veh- 1 km- 1) were estimated and compared with those obtained in other tunnel studies.

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

NASA Astrophysics Data System (ADS)

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

2012-12-01

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

Mapping PAH sizes in NGC 7023 with SOFIA

NASA Astrophysics Data System (ADS)

Croiset, B. A.; Candian, A.; Berné, O.; Tielens, A. G. G. M.

2016-05-01

Context. NGC 7023 is a well-studied reflection nebula, which shows strong emission from polycyclic aromatic hydrocarbon (PAH) molecules in the form of aromatic infrared bands (AIBs). The spectral variations of the AIBs in this region are connected to the chemical evolution of the PAH molecules which, in turn, depends on the local physical conditions. Aims: Our goal is to map PAH sizes in NGC 7023 with respect to the location of the star. We focus on the north west (NW) photo-dissociation region (PDR) and the south PDR of NGC 7023 to understand the photochemical evolution of PAHs, using size as a proxy. Methods: We use the unique capabilities of the Stratospheric Observatory for Infrared Astronomy (SOFIA) to observe a 3.2' × 3.4' region of NGC 7023 at wavelengths that we observe with high spatial resolution (2.7'') at 3.3 and 11.2 μm. We compare the SOFIA images with existing images of the PAH emission at 8.0 μm (Spitzer), emission from evaporating very small grains (eVSG) extracted from Spitzer-IRS spectral cubes, the extended red emission (Hubble Space Telescope and Canadian French Hawaiian Telescope), and H2 (2.12 μm). We create maps of the 11.2/3.3 μm ratio to probe the morphology of the PAH size distribution and the 8.0/11.2 μm ratio to probe the PAH ionization. We make use of an emission model and of vibrational spectra from the NASA Ames PAH database to translate the 11.2/3.3 μm ratio to PAH sizes. Results: The 11.2/3.3 μm ratio map shows the smallest PAH concentrate on the PDR surface (H2 and extended red emission) in the NW and south PDR. We estimated that PAHs in the NW PDR bear, on average, a number of carbon atoms (Nc) of ~70 in the PDR cavity and ~50 at the PDR surface. In the entire nebula, the results reveal a factor of 2 variation in the size of the PAH. We relate these size variations to several models for the evolution of the PAH families when they traverse from the molecular cloud to the PDR. Conclusions: The high-resolution PAH size map

Molecular Spectroscopy in Astrophysics: Interstellar PAHs

NASA Technical Reports Server (NTRS)

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

2000-01-01

Polycyclic aromatic hydrocarbons (PAHs) are now considered to be an important and ubiquitous component of the organic material in space. PAHs are found in a large variety of extraterrestrial materials such as interplanetary dust particles (IDPs) and meteoritic materials. PAHs are also good candidates to account for the infrared emission bands (UIRs) and the diffuse interstellar optical absorption bands (DIBs) detected in various regions of the interstellar medium. The recent observations made with the Infrared Space Observatory (ISO) have confirmed the ubiquitous nature of the UIR bands and their carriers. PAHs are thought to form through chemical reactions in the outflow from carbon-rich stars in a process similar to soot formation. Once injected in the interstellar medium, PAHs are further processed by the interstellar radiation field, interstellar shocks and energetic particles. A long-term laboratory effort has been undertaken to measure the physical and chemical characteristics of these carbon molecules and their ions under experimental conditions that mimic the interstellar conditions. These measurements require collision-free conditions where the molecules and ions are cold and chemically isolated. The spectroscopy of PAHs under controlled conditions represents an essential diagnostic tool to study the evolution of extraterrestrial PAHs. The laboratory results will be discussed as well as the implications for astronomy and for molecular spectroscopy. A review of the data generated through laboratory simulations of space environments and the role these data have played in our current understanding of the properties of interstellar PAHs will be presented. We will also present the new generation of laboratory experiments that are currently being developed in order to provide a closer simulation of space environments and a better support to space missions.

Variation in PAH patterns in road runoff.

PubMed

Aryal, Rupak; Furumai, Hiroaki; Nakajima, Fumiyuki; Beecham, Simon

2013-01-01

Twelve particle-bound polycyclic aromatic hydrocarbons (PAHs) were measured in the first flush regime of road runoff during nine events in Winterthur in Switzerland. The total PAH contents ranged from 17 to 62 μg/g. The PAH patterns measured at different time intervals during the first flush periods were very similar within each event irrespective of variation in suspended solids (SS) concentration within the first flush regime. However, the PAH patterns were different from event to event. This indicates that the environment plays an important role in PAH accumulation in SS. A toxicity identification evaluation approach using a toxicity equivalency factor (TEF) was applied to compare toxicities in the different events. The TEFs were found to be between 8 and 33 μg TEQ g(-1) (TEQ: toxic equivalent concentration). In some cases, two events having similar total PAH contents showed two fold toxicity differences.

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

NASA Astrophysics Data System (ADS)

Boersma, Christiaan

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

Interstellar PAH Emission in the 11-14 micron Region: New Insights and a Tracer of Ionized PAHs

NASA Technical Reports Server (NTRS)

Hudgins, Douglas M.; Allamandola, Louis J.; Mead, Susan (Technical Monitor)

1999-01-01

The Ames infrared spectral database of isolated, neutral and ionized polycyclic aromatic hydrocarbons (PAHs) shows that aromatic CH out-of-plane bending frequencies are significantly shifted upon ionization. For non-adjacent and doubly-adjacent CH groups, the shift is pronounced and consistently toward higher frequencies. The non-adjacent modes are blueshifted by an average of 27 per cm and the doubly-adjacent modes by an average of 17 per cm. For triply- and quadruply-adjacent CH out-of-plane modes the ionization shifts are more erratic and typically more modest. As a result of these ionization shifts, both the non-adjacent and doubly-adjacent CH out-of-plane modes move out of the regions classically associated with their respective vibrations in neutral PAHs. The doubly-adjacent modes of ionized PAHs tend to fall into the frequency range traditionally associated with the non-adjacent modes, while the non-adjacent modes are shifted to frequencies above those normally attributed to out-of-plane bending vibrations. Consequently, the origin of the interstellar infrared emission feature near 11.2 microns, traditionally attributed to the out-of-plane bending of non-adjacent CH groups on PAHs is rendered ambiguous. Instead, this feature likely reflects contributions from both non-adjacent CH units in neutral PAHs and doubly-adjacent CH units in PAH cations, the dominant charge state in the most energetic emission regions. This greatly relieves the structural constraints placed on the interstellar PAH population by the dominance of the 11.2 micron band in this region and eliminates the necessity to invoke extensive dehydrogenation of the emitting species. Furthermore, these results indicate that the emission between 926 and 904 per cm (10.8 and 11.1 microns) observed in many sources can be unambiguously attributed to the non-adjacent CH out-of-plane bending modes of moderately-sized (fewer than 50 carbon atom) PAH cations making this emission an unequivocal tracer of

Laboratory Studies of Interstellar PAH Analogs

NASA Technical Reports Server (NTRS)

Salama, Farid; DeVincenzi, Donald (Technical Monitor)

2000-01-01

Polycyclic aromatic hydrocarbons (PAHs) are now considered to be an important and ubiquitous component of the organic material in space. PAHs are found in a large variety of extraterrestrial materials such as interplanetary dust particles (IDPs) and meteoritic materials. PAHs are also good candidates to account for the infrared emission bands (UIRs) and the diffuse interstellar optical absorption bands (DIBs) detected in various regions of the interstellar medium. The recent observations made with the Infrared Space Observatory (ISO) have confirmed the ubiquitous nature of the UIR bands and their carriers. PAHs are though to form through chemical reactions in the outflow from carbon-rich stars in a process similar to soot formation. Once injected in the interstellar medium, PAHs are further processed by the interstellar radiation field, interstellar shocks and energetic particles. A major, dedicated, laboratory effort has been undertaken over the past years to measure the physical and chemical characteristics of these complex molecules and their ions under experimental conditions that mimic the interstellar conditions. These measurements require collision-free conditions where the molecules and ions are cold and chemically isolated. The spectroscopy of PAHs under controlled conditions represents an essential diagnostic tool to study the evolution of extraterrestrial PAHs. The Astrochemistry Laboratory program will be discussed through its multiple aspects: objectives, approach and techniques adopted, adaptability to the nature of the problem(s), results and implications for astronomy as well as for molecular spectroscopy. A review of the data generated through laboratory simulations of space environments and the role these data have played in our current understanding of the properties of interstellar PAHs will be presented. The discussion will also introduce the newest generation of laboratory experiments that are currently being developed in order to provide a

PAHs in polystyrene food contact materials: An unintended consequence.

PubMed

Li, Si-Qi; Ni, Hong-Gang; Zeng, Hui

2017-12-31

Eight low-ring PAHs were detected in 21 polystyrene (PS) food contact materials (FCMs) samples while high-ring PAHs (>4 rings) were not found. This is because the reaction pathway for formation of high-ring PAHs consists of more steps than it does for low-high PAHs. The concentrations of Σ 8 PAH were from 18.9±5.16ng/g for product colorless fruit fork to 476±52.0ng/g for foam instant noodle container. These data were far beyond levels of PAHs in other plastics. Of the eight PAHs detected, Phe had the highest average concentration, followed by Nap. These two PAHs collectively accounted for over 80% of the Σ 8 PAH concentrations in all PS FCMs. Levels of Σ 8 PAH in expanded PS FCMs were higher than those in extruded ones due to utilization of foaming agent. The concentrations of Σ 8 PAH were lower in colorless PS FCMs than in colored ones. Auxochromes and chromophores contributed to the change of short-chain hydrocarbons to aromatic hydrocarbon. Simulated migration values of PAHs from PS FCMs to food varied widely. The migration value of Σ 8 PAH with maximum probability was below 10ng/g, which the maximum tolerated migration level for substance according to the European Union standards. However, higher migration values were possible and the potential health risk should still be concerned because the simulated migration displayed a log-normal distribution. Furthermore, water was used as food simulant would always lead to an underestimate of PAHs migration to real daily food, and then lead to an underestimate of risk. Copyright © 2017 Elsevier B.V. All rights reserved.

Infrared spectra of interstellar deuteronated PAHs

NASA Astrophysics Data System (ADS)

Buragohain, Mridusmita; Pathak, Amit; Sarre, Peter

2015-08-01

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

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

PubMed

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

2016-10-01

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

Changes in PAH levels during production of rapeseed oil.

PubMed

Cejpek, K; Hajslová, J; Kocourek, V; Tomaniová, M; Cmolík, J

1998-07-01

The influence of technological operations during rapeseed oil production on polycyclic aromatic hydrocarbon (PAH) concentrations in by-products, intermediate and final oils was evaluated. The decrease of light PAHs, benz(a)anthracene and benzo(a)pyrene during processing of crude oil to the deodorized product was significant at the 95% confidence interval in most batches analysed. Deodorization and alkali-refining were the steps contributing most to the PAH decrease. The relationship between PAH levels in rapeseed (and consequently in refined oil) and the duration of storage period was studied. The contamination of raw material processed a short time after harvesting was significantly higher than that of the rapeseed stored in silos for several months. Analyses of rapeseed samples, which were re-purified in the laboratory, revealed that solid particles, which contaminate rapeseed during harvesting, initial treatment, transport and storage, contributed to PAH contamination to the extent of 36% (light PAHs) to 64% (heavy PAHs) on average. Further experiments demonstrated that PAHs in re-purified rapeseed were concentrated in the cuticular layer, because they were removed well from the whole seeds by simple rinsing with organic solvent in an ultrasonic bath without losses of rapeseed oil. Alternative expressions of total PAH contamination (e.g. various PAH groups and/or differently defined B(a)P toxic equivalents) are discussed and their effect on drawing conclusions about PAH elimination rate has been demonstrated.

Correlations between PAH bioavailability, degrading bacteria, and soil characteristics during PAH biodegradation in five diffusely contaminated dissimilar soils.

PubMed

Crampon, M; Bureau, F; Akpa-Vinceslas, M; Bodilis, J; Machour, N; Le Derf, F; Portet-Koltalo, F

2014-01-01

The natural biodegradation of seven polycyclic aromatic hydrocarbons (PAHs) by native microorganisms was studied in five soils from Normandy (France) from diffusely polluted areas, which can also pose a problem in terms of surfaces and amounts of contaminated soils. Bioavailability tests using cyclodextrin-based extractions were performed. The natural degradation of low molecular weight (LMW) PAHs was not strongly correlated to their bioavailability due to their sorption to geosorbents. Conversely, the very low degradation of high molecular weight (HMW) PAHs was partly correlated to their poor availability, due to their sorption on complexes of organic matter and kaolinites or smectites. A principal component analysis allowed us to distinguish between the respective degradation behaviors of LMW and HMW PAHs. LMW PAHs were degraded in less than 2-3 months and were strongly influenced by the relative percentage of phenanthrene-degrading bacteria over total bacteria in soils. HMW PAHs were not significantly degraded, not only because they were less bioavailable but also because of a lack of degrading microorganisms. Benzo[a]pyrene stood apart since it was partly degraded in acidic soils, probably because of a catabolic cooperation between bacteria and fungi.

Comparison of spatial and temporal variations in p-PAH, BC, and p-PAH/BC ratio in six US counties

NASA Astrophysics Data System (ADS)

Han, Inkyu; Ramos-Bonilla, Juan P.; Rule, Ana M.; Mihalic, Jana N.; Polyak, Lisa M.; Breysse, Patrick N.; Geyh, Alison S.

2011-12-01

An ambient air monitoring campaign was performed in six counties (Sacramento, CA; Maricopa, AZ; Anoka, MN; Jefferson, KY; Harris, TX; and Pinellas, FL) between January 2008 and September 2009. The purpose of this paper is to compare the spatial and temporal variability of black carbon (BC) and particle-bound polycyclic aromatic hydrocarbons (p-PAHs), across these counties using continuous monitoring instruments - an Aethalometer and a Photoelectric Aerosol Sensor reporting in units of μg m -3 and fA, respectively. We explored temporal trends in these measurements to assess the potential impact of local combustion sources on air quality. Median BC concentrations ranged from 0.13 to 0.53 μg m -3; and median p-PAH values ranged from 0.31 to 4.18 fA. Hourly BC and p-PAH were elevated during morning rush hour and rapidly decreased later in the morning. Nighttime increases in BC and p-PAH were also observed in most counties. Diurnal patterns of BC and p-PAH were different on weekdays compared to weekends. Profiles of hourly ratios of p-PAH/BC in combination with meteorological data can provide insight into potential sources across the sites. Hourly ratios of p-PAH/BC which peaked during early morning and late afternoon hours suggest a dominating contribution of motor vehicle sources in four of the six counties. In two counties, hourly ratios remained elevated for several hours after rush hour and did not show a distinctive peak suggesting additional sources of BC and p-PAH. Such profiles were seen in both Jefferson KY and Harris TX, and may be attributed to coal combustion, petro-chemical industry and shipping activities, respectively. These results suggest that measurements of BC and p-PAH, combined with meteorological information and emission data are potentially useful to identify combustion sources impacting air quality. More research combining BC and p-PAH measurements with detailed source apportionment data is needed to more fully evaluate the utility of these

Infrared fluorescence from PAHs in the laboratory

NASA Technical Reports Server (NTRS)

Cherchneff, Isabelle; Barker, John R.

1989-01-01

Several celestial objects, including UV rich regions of planetary and reflection nebulae, stars, H II regions, and extragalactic sources, are characterized by the unidentified infrared emission bands (UIR bands). A few years ago, it was proposed that polycyclic aromatic hydrocarbon species (PAHs) are responsible for most of the UIR bands. This hypothesis is based on a spectrum analysis of the observed features. Comparisons of observed IR spectra with lab absorption spectra of PAHs support the PAH hypothesis. An example spectrum is represented, where the Orion Bar 3.3 micron spectrum is compared with the absorption frequencies of the PAHs Chrysene, Pyrene, and Coronene. The laser excited 3.3 micron emission spectrum is presented from a gas phase PAH (azulen). The infrared fluorescence theory (IRF) is briefly explained, followed by a description of the experimental apparatus, a report of the results, and discussion.

Degradation of polycyclic aromatic hydrocarbons (PAHs) during Sphagnum litters decay.

PubMed

Wang, Zucheng; Liu, Shasha; Bu, Zhao-Jun; Wang, Shengzhong

2018-04-28

The dynamics of polycyclic aromatic hydrocarbon (PAH) degradation in Sphagnum litters and the decomposition of the litters were investigated. PAH concentration decreased to approximately half of the initial concentration as Sphagnum litters decayed. The initial PAH concentration was 489.2 ± 72.2 ng g -1 , and the concentration after 120 days of incubation was 233.0 ± 5.8 ng g -1 . The different PAH compositions changed concentrations at different times. The low-molecular-weight (LMW) and high-molecular-weight (HMW) PAHs started to be degraded after incubation and after 40 days of incubation, respectively. PAH concentrations in the Sphagnum litters correlated with the total organic carbon (TOC) content (p < 0.05), indicating that PAHs were associated with the TOC of the Sphagnum litters and were degraded as organic matter decayed. The positive relationship between LMW PAH concentration and the soluble carbohydrate content (p < 0.05) indicated that LMW PAHs and the readily decomposed organic carbon fractions were cometabolized, or that LMW PAHs were mainly absorbed by soluble carbohydrate. The weak negative correlation between fulvic acid (FA) and PAH concentrations (p < 0.1) indicated that FA may enhance PAH degradation. Redundancy analysis suggested that the contents of both soluble carbohydrate and cellulose significantly affected the changes in PAH concentrations (p < 0.05), and that FA content and C/N ratios may also contribute to the changes in PAH concentrations (p < 0.1). However, the polyphenol that was related to microbial activities was not associated with changes in PAH concentrations. These results suggested that litter quality is more important than microbial activities in PAH degradation in Sphagnum litters.

PAHs (Polycyclic Aromatic Hydrocarbons), Nitro-PAHs, Hopanes and Steranes Biomarkers in Sediments of Southern Lake Michigan, USA

PubMed Central

Huang, Lei; Chernyak, Sergei M.; Batterman, Stuart A.

2014-01-01

PAHs in the Great Lakes basin are of concern due to their toxicity and persistence in bottom sediments. Their nitro derivatives, nitro-PAHs (NPAHs), which can have stronger carcinogenic and mutagenic activity than parent PAHs, may follow similar transport routes and also are accumulated in sediments. Limited information exists regarding the current distribution, trends and loadings of these compounds, especially NPAHs, in Lake Michigan sediments. This study characterizes PAHs, NPAHs, and biomarkers steranes and hopanes in surface sediments collected at 24 offshore sites in southern Lake Michigan. The ΣPAH14 (sum of 14 compounds) ranged from 213 to 1291 ng/g dry weight (dw) across the sites, levels that are 2 to 10 times lower than those reported 20 to 30 years earlier. Compared to consensus-based sediment quality guidelines, PAH concentrations suggest very low risk to benthic organisms. The ΣNPAH5 concentration ranged from 2.9 to 18.6 ng/g dw, and included carcinogenic compounds 1-nitropyrene and 6-nitrochrysene. ΣSterane6 and ΣHopane5 concentrations ranged from 6.2 to 36 and 98 to 355 ng/g dw, respectively. Based on these concentrations, Lake Michigan is approximately receiving 11, 0.16, 0.25 and 3.6 metric tons per year (t/yr) of ΣPAH14, ΣNPAH5, ΣSterane6 and ΣHopane5, respectively. Maps of OC-adjusted concentrations display that concentrations decline with increasing off-shore distance. The major sources of PAHs and NPAHs are pyrogenic in nature, based on diagnostic ratios. Using chemical mass balance models, sources were apportioned to emissions from diesel engines (56±18%), coal power plants (27±14%), coal-tar pavement sealants (16±11%), and coke ovens (7±12%). The biomarkers identify a combination of petrogenic and biogenic sources, with the southern end of the lake more impacted by petroleum. This first report of NPAHs levels in sediments of Lake Michigan reveals several carcinogenic compounds at modest concentrations, and a need for further work

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

PubMed

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

2016-11-15

The objective of this study was to characterize parent polycyclic aromatic hydrocarbons (pPAHs) and their nitrated derivatives (NPAHs) in coarse (PM2.5-10), intermediate (PM1-2.5) and fine (PM1) particulate matters emitted from coal-fired power plants (CFPPs) in Huainan, China. The diagnostic ratios and the stable carbon isotopic approaches to characterize individual PAHs were applied in order to develop robust tools for tracing the origins of PAHs in different size-segregated particular matters (PMs) emitted CFPP coal combustion. The concentrations of PAH compounds in flue gas emissions varied greatly, depending on boiler types, operation and air pollution control device (APCD) conditions. Both pPAHs and NPAHs were strongly enriched in PM1-2.5 and PM1. In contrary to low molecular weight (LMW) PAHs, high molecular weight (HMW) PAHs were more enriched in finer PMs. The PAH diagnostic ratios in size-segregated PMs are small at most cases, highlighting their potential application in tracing CFPP emitted PAHs attached to different sizes of PMs. Yet, substantial uncertainty still exists to directly apply PAH diagnostic ratios as emission tracers. Although the stable carbon isotopic composition of PAH molecular was useful in differentiating coal combustion emissions from other sources such as biomass combustion and vehicular exhausts, it was not feasible to differentiate isotopic fractionation processes such as low-temperature carbonization, high-temperature carbonization, gasification and combustion. Copyright © 2016 Elsevier B.V. All rights reserved.

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

PubMed

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

2016-06-01

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

Development of the Pulmonary Arterial Hypertension-Symptoms and Impact (PAH-SYMPACT®) questionnaire: a new patient-reported outcome instrument for PAH.

PubMed

McCollister, Deborah; Shaffer, Shannon; Badesch, David B; Filusch, Arthur; Hunsche, Elke; Schüler, René; Wiklund, Ingela; Peacock, Andrew

2016-06-14

Regulators and clinical experts increasingly recognize the importance of incorporating patient-reported outcomes (PROs) in clinical studies of therapies for pulmonary arterial hypertension (PAH). No PAH-specific instruments have been developed to date in accordance with the 2009 FDA guidance for the development of PROs as endpoints in clinical trials. A qualitative research study was conducted to develop a new instrument assessing PAH symptoms and their impacts following the FDA PRO guidance. A cross-sectional study was conducted at 5 centers in the US in symptomatic PAH patients aged 18-80 years. Concept elicitation was based on 5 focus group discussions, after which saturation of emergent concepts was reached. A PRO instrument for PAH symptoms and their impacts was drafted. To assess the appropriateness of items, instructions, response options, and recall periods, 2 rounds of one-on-one cognitive interviews were conducted, with instrument revisions following each round. Additional interviews tested the usability of an electronic version (ePRO). PRO development considered input from an international Steering Committee, and translatability and lexibility assessments. Focus groups comprised 25 patients (5 per group); 20 additional patients participated in cognitive interviews (10 per round); and 10 participated in usability interviews. Participants had a mean ± SD age of 53.1 ± 15.8 years, were predominantly female (93 %), and were diverse in race/ethnicity, WHO functional class (FC I/II: 56 %, III/IV: 44 %), and PAH etiology (idiopathic: 56 %, familial: 2 %, associated: 42 %). The draft PRO instrument (PAH-SYMPACT®) was found to be clear, comprehensive, and relevant to PAH patients in cognitive interviews. Items were organized in a draft conceptual framework with 16 symptom items in 4 domains (respiratory symptoms, tiredness, cardiovascular symptoms, other symptoms) and 25 impact items in 5 domains (physical activities, daily activities, social

[PAH exposure in asphalt workers].

PubMed

Garattini, Siria; Sarnico, Michela; Benvenuti, Alessandra; Barbieri, P G

2010-01-01

There has been interest in evaluating the potential carcinogenicity of bitumen fumes in asphalt workers since the 1960's. The IARC classified air-refined bitumens as possible human carcinogens, while coal-tar fumes were classified as known carcinogens. Occupational/environmental PAH exposure can be measured by several urinary markers. Urinary 1-OHP has become the most commonly used biological marker of PAH exposure in asphalt workers. The aim of this study was to assess asphalt workers' exposure levels by monitoring 1-OHP urinary excretion and compare this data with those of non-occupationally exposed subjects. We investigated three groups of asphalt workers: 100 in summer 2007, 29 in winter 2007, and 148 during summer 2008 and compared 1-OHP urinary concentrations using Kruskall-Wallis test. Median 1-OHP urinary concentrations during the three biomonitoring sampling periods were 0.65, 0.17 and 0.53 microg/g creatinine respectively. There was a significant difference in 1-OHP values between the three groups (p < 0.001). our study showed that PAH exposure of asphalt workers' is higher than that observed in the general population and in workers in urban areas. Our results suggest that PAH exposure in the three groups studied is not sufficiently kept under control by the use of personal protective equipment and that biomonitoring is useful in evaluating PAH exposure and for risk assessment. Regulations need to be enforced for workers exposed to cancer risk, such as the register of workers exposed to carcinogens.

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

PubMed Central

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

2012-01-01

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

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

PubMed

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

2015-10-01

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

Global time trends in PAH emissions from motor vehicles

NASA Astrophysics Data System (ADS)

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

2011-04-01

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

Biodegradation of PAHs in Soil: Influence of Initial PAHs Concentration

NASA Astrophysics Data System (ADS)

Kamil, N. A. F. M.; Talib, S. A.

2016-07-01

Most studies on biodegradation of Polycyclic Aromatic Hydrocarbons (PAHs) evaluate the effect of initial PAHs concentration in liquid medium. There are limited studies on evaluation in solid medium such as contaminated soil. This study investigated the potential of the bacteria, Corynebacterium urealyticum isolated from municipal sludge in degrading phenanthrene contaminated soil in different phenanthrene concentration. Batch experiments were conducted over 20 days in reactors containing artificially contaminated phenanthrene soil at different concentration inoculated with a bacterial culture. This study established the optimum condition for phenanthrene degradation by the bacteria under nonindigenous condition at 500 mg/kg of initial phenanthrene concentration. High initial concentration required longer duration for biodegradation process compared to low initial concentration. The bacteria can survive for three days for all initial phenanthrene concentrations.

Uptake of PAHs by cabbage root and leaf in vegetable plots near a large coking manufacturer and associations with PAHs in cabbage core.

PubMed

Xiong, GuanNan; Zhang, YunHui; Duan, YongHong; Cai, ChuanYang; Wang, Xin; Li, JingYa; Tao, Shu; Liu, WenXin

2017-08-01

Samples of ambient air (including gaseous and particulate phases), dust fall, surface soil, rhizosphere soil, core (edible part), outer leaf, and root of cabbage from eight vegetable plots near a large coking manufacturer were collected during the harvest period. Concentrations, compositions, and distributions of parent PAHs in different samples were determined. Our results indicated that most of the parent PAHs in air occurred in the gaseous phase, dominated by low molecular weight (LMW) species with two to three rings. Specific isomeric ratios and principal component analysis were employed to preliminarily identify the local sources of parent PAHs emitted. The main emission sources of parent PAHs could be apportioned as a mixture of coal combustion, coking production, and traffic tailing gas. PAH components with two to four rings were prevailing in dust fall, surface soil, and rhizosphere soil. Concentrations of PAHs in surface soil exhibited a significant positive correlation with topsoil TOC fractions. Compositional profiles in outer leaf and core of cabbage, dominated by LMW species, were similar to those in the local air. Overall, the order of parent PAH concentration in cabbage was outer leaf > root > core. Partial correlation analysis and multivariate linear stepwise regression revealed that PAH concentrations in cabbage core were closely associated with PAHs present both in root and in outer leaf, namely, affected by adsorption, then absorption, and translocation of PAHs from rhizosphere soil and ambient air, respectively.

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

PubMed

Wang, Ruwei; Liu, Guijian; Zhang, Jiamei

2015-12-15

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

[Polycyclic aromatic hydrocarbons (PAHs) in herbs and fruit teas].

PubMed

Ciemniak, Artur

2005-01-01

Polycyclic aromatic hydrocarbons (PAHs) of which benzo[a]pyrene is the most commonly studied and measured, are fused - ring aromatic compounds formed in both natural and man made processes and are found widely distributed throughout the human environment. PAHs occur as contaminants in different food categories and beverages including water, vegetables, fruit, cereals, oils and fats, barbecued and smoked meat. The sources of PAHs in food are predominantly from environmental pollution and food processing. PAHs emissions from automobile traffic and industry activities were show to influence the PAHs levels in vegetables and fruits. The present study was carried out to determine levels of 16 basic PAHs in herbs and fruit teas. The method was based on the hexane extraction and cleaned up by florisil cartridge. The extracts were analysed by GC-MS. The levels of total PAHs varied from 48,27 microg/kg (hibiscus tea) to 1703 microg/kg (green tea). The highest level of BaP was found in lime tea (74,2 microg/kg).

Polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs and related environmental compounds: biological markers of exposure and effects.

PubMed Central

Talaska, G; Underwood, P; Maier, A; Lewtas, J; Rothman, N; Jaeger, M

1996-01-01

Lung cancer caused by polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs and related environmental agents is a major problem in industrialized nations. The high case-fatality rate of the disease, even with the best supportive treatment, underscores the importance of primary lung cancer prevention. Development of biomarkers of exposure and effects to PAHs and related compounds is now underway and includes measurement of urinary metabolites of specific PAHs as well as detection of protein and DNA adducts as indicators of effective dose. Validation of these markers in terms of total environmental dose requires that concurrent measures of air levels and potential dermal exposure be made. In addition, the interrelationships between PAH biomarkers must be determined, particularly when levels of the marker in surrogate molecules (e.g., protein) or markers from surrogate tissues (e.g., lymphocyte DNA) are used to assess the risk to the target organ, the lung. Two approaches to biomarker studies will be reviewed in this article: the progress made using blood lymphocytes as surrogates for lung tissues and the progress made developing noninvasive markers of carcinogen-DNA adduct levels in lung-derived cells available in bronchial-alveolar lavage and in sputum. Data are presented from studies in which exfoliated urothelial cells were used as a surrogate tissue to assess exposure to human urinary bladder carcinogens in occupational groups. PMID:8933032

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

PubMed

Rauscher, Lindy; Sakulthaew, Chainarong; Comfort, Steve

2012-11-30

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

[Characterization of PAHs in fly ashes from coke production].

PubMed

Mu, Ling; Peng, Lin; Liu, Xiao-Feng; Bai, Hui-Ling; Zhang, Jian-Qiang

2013-03-01

In order to investigate the characteristics of polycyclic aromatic hydrocarbons (PAHs) in ashes from coking, PAHs in ashes from three coke production plants were analyzed with GC-MS, and the distribution characteristics of PAHs and potential toxicity risk were discussed. The sum of 16 EPA prior PAHs varied from 8.17 x 10(2) to 5.17 x 10(3) microg x g(-1). PAH contents from the coke oven (stamp charging) with the height of 3.2 m were two times higher than those from the one (top charging) with the height of 6.0 m, and PAHs in ashes from coal charging were significantly higher than those from coke pushing in the same plant. Four-ring and five-ring PAHs were the dominant species in ashes from coking and the sum of them accounted for more than 80.00% of total PAHs. Chrysene (Chr), benzo [a] anthracene (BaA) and benzo [b] fluoranthene (BbF) were abundant in all ash samples. The content of total BaP-based toxic equivalency (BaPeq) ranged from 1.64 x 10(2) to 9.57 x 10(2) microg x g(-1). From the carcinogenic point of view, besides benzo [a] pyrene (BaP), dibenz [a,h] anthracene (DbA) contributed most to the overall toxicity of PAHs, followed by BaA and BbF. BaPeq concentration from coal charging was 5.21-fold higher than that from coke pushing, indicating that different reuse ways should be considered based on their specific toxicity profiles of PAHs.

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

USGS Publications Warehouse

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

2012-01-01

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

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

PubMed Central

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

2015-01-01

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

PAH in the laboratory and interstellar space

NASA Technical Reports Server (NTRS)

Wdowiak, Thomas J.; Flickinger, Gregory C.; Boyd, David A.

1989-01-01

The theory that polycyclic aromatic hydrocarbons (PAHs) are a constituent of the interstellar medium, and a source of the IR emission bands at 3.3, 6.2, 7.7, 8.6, and 11.3 microns is being studied using PAH containing acid insoluble residue of the Orgueil CI meteorite and coal tar. FTIR spectra of Orgueil PAH material that has undergone thermal treatment, and a solvent insoluble fraction of coal tar that has been exposed to hydrogen plasma are presented. The UV excided luminescence spectrum of a solvent soluble coal tar film is also shown. Comparison of the lab measurements with observations appears to support the interstellar PAH theory, and shows the process of dehydrogenation expected to take place in the interstellar medium.

Degradation of polycyclic aromatic hydrocarbons (PAHs) by a mixed culture and its component pure cultures, obtained from PAH-contaminated soil.

PubMed

Trzesicka-Mlynarz, D; Ward, O P

1995-06-01

A mixed culture, isolated from soil contaminated with polycyclic aromatic hydrocarbons (PAHs), grew on and degraded fluoranthene in aqueous media supplemented with glucose, yeast extract, and peptone. Increased complex nitrogen levels in the medium promoted bacterial growth and a greater extent of fluoranthene degradation. Amendment of the media with high glucose levels also diminished specific fluoranthene degradation. The mixed culture was capable of degrading a range of other PAHs, including benzo[a]pyrene, anthracene, phenanthrene, acenaphthene, and fluorene. The mixed culture contained four predominant isolates, all of which were Gram-negative rods, three of which were identified as Pseudomonas putida, Flavobacterium sp., and Pseudomonas aeruginosa. Better degradation of a defined PAH mixture was observed with the mixed culture than with individual isolates. A reconstituted culture, prepared by combining the four individual isolates, manifested a similar PAH biodegradation performance to the original mixed culture. When compared with the mixed culture, individual isolates exhibited a relatively good capacity to remove more water-soluble PAHs (acenaphthene, fluorene, phenanthrene, fluoranthene). In contrast, removal of less water-soluble PAHs (anthracene and pyrene) was low or negligible with isolated cultures compared with the mixed culture.

PAH Formation in O-rich Evolved Stars

NASA Astrophysics Data System (ADS)

Guzman-Ramirez, L.; Lagadec, E.; Jones, D.; Zijlstra, A. A.; Gesicki, K.

2015-08-01

Polycyclic aromatic hydrocarbons (PAHs) have been observed in O-rich planetary nebulae. This combination of oxygen-rich and carbon-rich material, known as dual-dust or mixed chemistry, is not expected to be seen around these objects. We recently proposed that PAHs could be formed from the photodissociation of CO in dense tori. Using VISIR/VLT, we spatially resolved the emission of the PAH bands and ionised emission from the [S IV] line, confirming the presence of dense central tori in all the observed O-rich objects. Furthermore, we show that for most of the objects, PAHs are located at the outer edge of these dense/compact tori, while the ionised material is mostly present in the inner parts, consistent with our hypothesis for the formation of PAHs in these systems. The presence of a dense torus has been strongly associated with the action of a central binary star and, as such, the rich chemistry seen in these regions may also be related to the formation of exoplanets in post-common-envelope binary systems.

Quantification of polycyclic aromatic hydrocarbons (PAHs) in human hair by HPLC with fluorescence detection: a biological monitoring method to evaluate the exposure to PAHs.

PubMed

Toriba, Akira; Kuramae, Yayoi; Chetiyanukornkul, Thaneeya; Kizu, Ryoichi; Makino, Tsunehisa; Nakazawa, Hiroyuki; Hayakawa, Kazuichi

2003-01-01

A high-performance liquid chromatographic (HPLC) method with fluorescence detection was developed for the quantification of polycyclic aromatic hydrocarbons (PAHs) in human hair. Fifteen kinds of PAHs classified as priority pollutants by the US EPA were quantified with four perdeuterated PAHs as internal standards. After 50 mg hair samples were washed with n-hexane to remove external contamination of PAHs, the samples were digested in 2.5 M sodium hydroxide. The digests were extracted with n-hexane and then analyzed by HPLC. Eleven kinds of PAHs were identified in hair samples of 20 subjects, and 10 kinds of PAHs were eventually quantified using the internal standards. For anthracene, chrysene and benzo[k]fluoranthene, significant differences were observed between smokers and non-smokers. Although benzo[b]fluoranthene, dibenz[a,h]anthracene, benzo[ghi]perylene and indeno[1,2,3-cd]pyrene were observed in the particulates of indoor and outdoor air, they were not detected in all hair samples. The analysis of PAHs in human hair should be useful as a new biomarker to evaluate the exposure to PAHs.

PAH volatilization following application of coal-tar-based pavement sealant

USGS Publications Warehouse

Van Metre, Peter C.; Majewski, Michael S.; Mahler, Barbara J.; Foreman, William T.; Braun, Christopher L.; Wilson, Jennifer T.; Burbank, Teresa L.

2012-01-01

Coal-tar-based pavement sealants, a major source of PAHs to urban water bodies, have recently been identified as a source of volatile PAHs to the atmosphere. We tracked the volatilization of PAHs for 1 year after application of a coal-tar-based pavement sealant by measuring gas-phase PAH concentrations above the pavement surface and solid-phase PAH concentrations in sealant scraped from the surface. Gas-phase concentrations at two heights (0.03 and 1.28 m) and wind speed were used to estimate volatilization flux. The sum of the concentrations of eight frequently detected PAHs (ΣPAH8) in the 0.03-m sample 1.6 h after application (297,000 ng m-3) was about 5000 times greater than that previously reported for the same height above unsealed parking lots (66 ng m-3). Flux at 1.6 h after application was estimated at 45,000 μg m-2 h-1 and decreased rapidly during the 45 days after application to 160 μg m-2 h-1. Loss of PAHs from the adhered sealant also was rapid, with about a 50% decrease in solid-phase ΣPAH8 concentration over the 45 days after application. There was general agreement, given the uncertainties, in the estimated mass of ΣPAH8 lost to the atmosphere on the basis of air sampling (2–3 g m-2) and adhered sealant sampling (6 g m-2) during the first 16 days after application, translating to a loss to the atmosphere of one-quarter to one-half of the PAHs in the sealcoat product. Combining the estimated mass of ΣPAH8 released to the atmosphere with a national-use estimate of coal-tar-based sealant suggests that PAH emissions from new coal-tar-based sealcoat applications each year (~1000 Mg) are larger than annual vehicle emissions of PAHs for the United States.

Decontamination of soils containing PAHs by electroremediation: a review.

PubMed

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

2010-05-15

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

PAH emissions from coal combustion and waste incineration.

PubMed

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

2016-11-15

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

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

PubMed

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

2016-01-01

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

Physical model for the photo-induced toxicity of polycyclic aromatic hydrocarbons (PAHs)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Greenburg, B.M.; Krylov, S.N.; Huang, H.D.

1994-12-31

A model for photo-induced toxicity of PAHs to duckweed was developed. Growth inhibition was described by photochemical reactions between PAHs and a hypothetical group of biomolecules (given the notation G) which are required for growth of the plants. Light activation of PAHs was considered in a two compartment system (water and leaves). The reaction scheme includes: photooxidation of PAHs, partitioning of PAHs into leaves, triplet formation of intact PAHs, photosensitization reactions that consume G, and reaction between photooxidized PAHs and G. The assumptions used in the model are: the rate of PAH photooxidation is slower than the rate of assimilation,more » PAH content in solution is approximately constant over the length of the toxicity test, the fluence rate of actinic radiation is lower in the leaves than in solution, the toxicity of intact PAHs with G in the absence of light is negligible, and the reaction of photooxidized PAHs with G does not require light. The authors then analyzed a series of differential equations that described toxicity. The result was an expression for growth inhibition as a function of the initial concentration of the PAH, the spectral distribution of the light source, the absorption spectrum of the PAH, the quantum yield for formation of triplet state PAH, and the rate of photo-oxidation of the PAH. The expression also includes two complex constants that can be solved by a least squares analysis of the empirical data for growth inhibition. Thus, the model allows a prediction of PAH photo-induced toxicity using only physical parameters of PAHs.« less

Interstellar PAH emission in the 11-14 micron region: new insights from laboratory data and a tracer of ionized PAHs

NASA Technical Reports Server (NTRS)

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

1999-01-01

The Ames infrared spectral database of isolated, neutral and ionized polycyclic aromatic hydrocarbons (PAHS) shows that aromatic CH out-of-plane bending frequencies are significantly shifted upon ionization. For solo- and duet-CH groups, the shift is pronounced and consistently toward higher frequencies. The solo-CH modes are blueshifted by an average of 27 cm-1 and the duet-CH modes by an average of 17 cm-1. For trio- and quartet-CH groups, the ionization shifts of the out-of-plane modes are more erratic and typically more modest. As a result of these ionization shifts, the solo-CH out-of-plane modes move out of the region classically associated with these vibrations in neutral PAHS, falling instead at frequencies well above those normally attributed to out-of-plane bending, vibrations of any type. In addition, for the compact PAHs studied, the duet-CH out-of-plane modes are shifted into the frequency range traditionally associated with the solo-CH modes. These results refine our understanding of the origin of the dominant interstellar infrared emission feature near 11.2 microns, whose envelope has traditionally been attributed only to the out-of-plane bending of solo-CH groups on PAHS, and provide a natural explanation for the puzzling emission feature near 11.0 microns within the framework of the PAH model. Specifically, the prevalent but variable long-wavelength wing or shoulder that is often observed near 11.4 microns likely reflects the contributions of duet-CH units in PAH cations. Also, these results indicate that the emission between 926 and 904 cm-1 (10.8 and 11.1 microns) observed in many sources can be unambiguously attributed to the out-of-plane wagging, of solo-CH units in moderately sized (fewer than 50 carbon atom) PAH cations, making this emission an unequivocal tracer of ionized interstellar PAHS.

Phytoavailability and mechanism of bound PAH residues in filed contaminated soils.

PubMed

Gao, Yanzheng; Hu, Xiaojie; Zhou, Ziyuan; Zhang, Wei; Wang, Yize; Sun, Bingqing

2017-03-01

Understanding the phytoavailability of bound residues of polycyclic aromatic hydrocarbons (PAHs) in soils is essential to assessing their environmental fate and risks. This study investigated the release and plant uptake of bound PAH residues (reference to parent compounds) in field contaminated soils after the removal of extractable PAH fractions. Plant pot experiments were performed in a greenhouse using ryegrass (Lolium multiflorum Lam.) to examine the phytoavailablility of bound PAH residues, and microcosm incubation experiments with and without the addition of artificial root exudates (AREs) or oxalic acid were conducted to examine the effect of root exudates on the release of bound PAH residues. PAH accumulation in the ryegrass after a 50-day growth period indicated that bound PAH residues were significantly phytoavailable. The extractable fractions, including the desorbing and non-desorbing fractions, dominated the total PAH concentrations in vegetated soils after 50 days, indicating the transfer of bound PAH residues to the extractable fractions. This transfer was facilitated by root exudates. The addition of AREs and oxalic acid to test soils enhanced the release of bound PAH residues into their extractable fractions, resulting in enhanced phytoavailability of bound PAH residues in soils. This study provided important information regarding environmental fate and risks of bound PAH residues in soils. Copyright © 2016 Elsevier Ltd. All rights reserved.

Environmental and individual PAH exposures near rural natural gas extraction.

PubMed

Paulik, L Blair; Hobbie, Kevin A; Rohlman, Diana; Smith, Brian W; Scott, Richard P; Kincl, Laurel; Haynes, Erin N; Anderson, Kim A

2018-05-29

Natural gas extraction (NGE) has expanded rapidly in the United States in recent years. Despite concerns, there is little information about the effects of NGE on air quality or personal exposures of people living or working nearby. Recent research suggests NGE emits polycyclic aromatic hydrocarbons (PAHs) into air. This study used low-density polyethylene passive samplers to measure concentrations of PAHs in air near active (n = 3) and proposed (n = 2) NGE sites. At each site, two concentric rings of air samplers were placed around the active or proposed well pad location. Silicone wristbands were used to assess personal PAH exposures of participants (n = 19) living or working near the sampling sites. All samples were analyzed for 62 PAHs using GC-MS/MS, and point sources were estimated using the fluoranthene/pyrene isomer ratio. ∑PAH was significantly higher in air at active NGE sites (Wilcoxon rank sum test, p < 0.01). PAHs in air were also more petrogenic (petroleum-derived) at active NGE sites. This suggests that PAH mixtures at active NGE sites may have been affected by direct emissions from petroleum sources at these sites. ∑PAH was also significantly higher in wristbands from participants who had active NGE wells on their properties than from participants who did not (Wilcoxon rank sum test, p < 0.005). There was a significant positive correlation between ∑PAH in participants' wristbands and ∑PAH in air measured closest to participants' homes or workplaces (simple linear regression, p < 0.0001). These findings suggest that living or working near an active NGE well may increase personal PAH exposure. This work also supports the utility of the silicone wristband to assess personal PAH exposure. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

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

PubMed

Ciemniak, Artur; Witczak, Agata

2010-01-01

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

Gas chromatographic retention behavior of polycyclic aromatic hydrocarbons (PAHs) and alkyl-substituted PAHs on two stationary phases of different selectivity.

PubMed

Nalin, Federica; Sander, Lane C; Wilson, Walter B; Wise, Stephen A

2018-01-01

Retention indices (I) for 45 polycyclic aromatic hydrocarbons (PAHs) and 63 methyl-substituted PAHs were determined by gas chromatography - mass spectrometry (GC-MS) using two different stationary phases: a Rxi-PAH phase (a "higher phenyl-content stationary phase") and a 50% (mole fraction) liquid crystalline dimethylpolysiloxane phase. Retention data were obtained for parent PAHs from molecular mass (MM) 128 g/mol (naphthalene) to 328 g/mol (benzo[c]picene) and for 12 sets of methyl-PAHs (methylfluorenes, methylanthracenes, methylphenanthrenes, methylfluoranthenes, methylpyrenes, methylbenz[a]anthracenes, methylbenzo[c]phenanthrenes, methylchrysenes, methyltriphenylenes, methylbenzo[a]pyrenes, methylperylenes, and methylpicenes). Molecular shape descriptors such as length-to-breath ratio (L/B) and thickness (T) were determined for all the PAHs studied. Correlation between I and L/B ratio was evaluated for both stationary phases with a better correlation observed for the 50% liquid crystalline phase (correlation coefficients ranging from 0.22 to 1.00). Graphical Abstract GC separation of six methylchrysene isomers (m/z 242) on two different stationary phases: 50 % phenyl-like methylpolysiloxane phase and 50 % liquid crystalline phase. Retention indices (I) are plotted as a function of L/B for both phases. The data marker numbers identify each isomer based on methyl-substitution position.

PAH and OPAH Flux during the Deepwater Horizon Incident

PubMed Central

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

2016-01-01

Passive sampling devices were used to measure air vapor and water dissolved phase concentrations of 33 polycyclic aromatic hydrocarbons (PAHs) and 22 oxygenated PAHs (OPAHs) at four Gulf of Mexico coastal sites prior to, during and after shoreline oiling from the Deepwater Horizon oil spill (DWH). Measurements were taken at each site over a 13 month period, and flux across the water-air boundary was determined. This is the first report of vapor phase and diffusive flux of both PAHs and OPAHs during the DWH. Vapor phase sum PAH and OPAH concentrations ranged between 6.6 and 210 ng/m3 and 0.02 and 34 ng/m3 respectively. PAH and OPAH concentrations in air exhibited different spatial and temporal trends than in water, and air-water flux of 13 individual PAHs was shown to be at least partially influenced by the DWH incident. The largest PAH volatilizations occurred at the sites in Alabama and Mississippi at nominal rates of 56,000 and 42,000 ng/m2/day in the summer. Naphthalene was the PAH with the highest observed volatilization rate of 52,000 ng/m2/day in June 2010. This work represents additional evidence of the DWH incident contributing to air contamination, and provides one of the first quantitative air-water chemical flux determinations with passive sampling technology. PMID:27391856

Spectroscopy of PAHs with carbon side chains

NASA Astrophysics Data System (ADS)

Rouille, G.; Steglich, M.; Carpentier, Y.; Huisken, F.; Henning, T.

2011-05-01

The presence of polycyclic aromatic hydrocarbons (PAHs) in space has been inferred ever since sp ecific infrared emission bands were interpreted as their collective fingerprint. In parallel, it has been admitted that the famous diffuse interstellar bands (DIBs), which are absorption features observed in the visible wavelength range, are bands belonging to the electronic spectra of free-flying interstellar molecules yet to be identified. As neutral PAHs of medium and large sizes exhibit absorption bands in the range where the DIBs are found, these molecules, which also fulfill other criteria, have been proposed as potential carriers. Studies of small PAHs in solutions have shown that adding an ethynyl side chain (--CCH) to their structure causes their electronic transitions to shift toward longer wavelengths. This fact, added to the observations of interstellar polyynyl radicals, motivated our current research project on PAHs carrying polyynyl side chains. In a first stage, we are measuring the electronic spectra of small PAHs and of their ethynyl and butadiynyl (--CCCCH) derivatives at cryogenic temperatures in rare gas matrices. Then, measurements will be carried out in supersonic jets, providing us with spectra obtained under conditions relevant to the study of free-flying interstellar molecules. The results of IR absorption measurements will be included in our set of new data. As a complement to our laboratory study on the substituted PAHs, quantum chemical calculations are carried out to interprete and simulate their IR and vibronic spectra. We use the density functional theory approach and its time-dependent extension for calculating the electronic ground states and the electronically excited states, respectively. Through the analysis of the new data, it will be determined whether PAHs carrying polyynyl side chains can play a role in interstellar phenomena. The latest results of this on-going project will be presented.

PAH formation in carbon-rich circumstellar envelopes

NASA Technical Reports Server (NTRS)

Feigelson, Eric D.; Frenklach, Michael

1989-01-01

While there is growing observational evidence that some fraction of interstellar carbon is in polycyclic aromatic hydrocarbons (PAH's), the mechanisms by which these molecules might be formed have not been extensively studied. A detailed investigation of PAH production in the outflowing molecular envelopes of carbon-rich red giant star is presented. The gasphase kinetics of a chemical reaction mechanism developed to study soot production in hydrocarbon flames is modified to apply in circumstellar environments. It was found that astrophysically significant quantities of PAH's can be formed in carbon star envelopes provided the gas is sufficiently dense and resides for a long time in the temperature range of 900 to 1100 k. The precise yield of PAH's is very sensitive to astronomical parameters of the envelope (e.g., mass loss rate, outflow velocity, and acetylene abundance) and certain poorly determined chemical reaction rates.

The PAH Emission Characteristics of the Reflection Nebula NGC 2023

NASA Astrophysics Data System (ADS)

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

2017-02-01

We present 5-20 μm spectral maps of the reflection nebula NGC 2023 obtained with the Infrared Spectrograph SL and SH modes on board the Spitzer Space Telescope, which reveal emission from polycyclic aromatic hydrocarbons (PAHs), C60, and H2 superposed on a dust continuum. We show that several PAH emission bands correlate with each other and exhibit distinct spatial distributions that reveal a spatial sequence with distance from the illuminating star. We explore the distinct morphology of the 6.2, 7.7, and 8.6 μm PAH bands and find that at least two spatially distinct components contribute to the 7-9 μm PAH emission in NGC 2023. We report that the PAH features behave independently of the underlying plateaus. We present spectra of compact, oval PAHs ranging in size from C66 to C210, determined computationally using density functional theory, and we investigate trends in the band positions and relative intensities as a function of PAH size, charge, and geometry. Based on the NASA Ames PAH database, we discuss the 7-9 μm components in terms of band assignments and relative intensities. We assign the plateau emission to very small grains with possible contributions from PAH clusters and identify components in the 7-9 μm emission that likely originate in these structures. Based on the assignments and the observed spatial sequence, we discuss the photochemical evolution of the interstellar PAH family as the PAHs are more and more exposed to the radiation field of the central star in the evaporative flows associated with the Photo-Dissociation Regions in NGC 2023.

Interstellar PAH Analogs in the Laboratory: Comparison with Astronomical Data

NASA Technical Reports Server (NTRS)

Salama, Farid

2005-01-01

Polycyclic Aromatic Hydrocarbons (PAHs) are an important and ubiquitous component of carbon-bearing materials in space. PAHs are the best-known candidates to account for the IR emission bands (UIR bands) and PAH spectral features are now being used as new probes of the ISM. PAHs are also thought to be among the carriers of the diffuse interstellar absorption bands (DIBs). In the model dealing with the interstellar spectral features, PAHs are present as a mixture of radicals, ions and neutral species. PAH ionization states reflect the ionization balance of the medium while PAH size, composition, and structure reflect the energetic and chemical history of the medium. A major challenge for laboratory astrophysics is to reproduce (in a realistic way) the physical conditions that exist in the emission and/or absorption interstellar zones. An extensive laboratory program has been developed at NASA Ames to assess the physical and chemical properties of PAHs in such environments and to describe how they influence the radiation and energy balance in space and the interstellar chemistry. In particular, laboratory experiments provide measurements of the spectral characteristics of interstellar PAH analogs from the ultraviolet and visible range to the infrared range for comparison with astronomical data. This paper will focus on the recent progress made in the laboratory to measure the direct absorption spectra of neutral and ionized PAHs in the near-UV and visible range. Intrinsic band profiles and band positions of cold gas-phase PAHs can now be measured with high-sensitivity spectroscopy and directly compared to the astronomical data. Preliminary conclusions from the comparison of the laboratory data with astronomical observations will also be presented.

Comparative Developmental Toxicity of Environmentally Relevant Oxygenated PAHs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knecht, Andrea; Goodale, Britton; Truong, Lisa

2013-09-01

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants in urban air, dust and in the soil of most industrial coal gassification, coal burning, coke production and wood preservation sites (Howsam and Jones 1998). It is widely recognized that PAHs pose risks to human health,having been associated with increased risks of systemic inflammation (Delfino et al. 2010), cardiopulmonary mortality (Lee et al. 2011; Lewtas 2007) and lung cancer mortality (Grant 2009; Hoshuyama et al. 2006). The potential risks may be especially acute for the developing fetus and infant where PAH exposures have been linked to low birth weight, intrauterine growth retardation, in-uteromore » mortality and lower intelligence (Dejmek et al. 1999; Dejmek et al. 2000; Perera et al. 1999; Perera et al. 2009; Perera et al. 2006; Perera et al. 1998; Wu et al. 2010). Despite the more than two decades of intensive study devoted to parent PAHs, they are only part of the hazard spectrum from PAH contamination.« less

LABORATORY PHOTO-CHEMISTRY OF PAHS: IONIZATION VERSUS FRAGMENTATION

PubMed Central

Zhen, Junfeng; Castellanos, Pablo; Paardekooper, Daniel M.; Ligterink, Niels; Linnartz, Harold; Nahon, Laurent; Joblin, Christine; Tielens, Alexander G. G. M.

2015-01-01

Interstellar Polycyclic Aromatic Hydrocarbons (PAH) are expected to be strongly processed by Vacuum Ultra-Violet (VUV) photons. Here, we report experimental studies on the ionization and fragmentation of coronene (C24H12), ovalene (C32H14) and hexa-peri-hexabenzocoronene (HBC; C42H18) cations by exposure to synchrotron radiation in the range of 8–40 eV. The results show that for small PAH cations such as coronene, fragmentation (H-loss) is more important than ionization. However, as the size increases, ionization becomes more and more important and for the HBC cation, ionization dominates. These results are discussed and it is concluded that, for large PAHs, fragmentation only becomes important when the photon energy has reached the highest ionization potential accessible. This implies that PAHs are even more photo-stable than previously thought. The implications of this experimental study for the photo-chemical evolution of PAHs in the interstellar medium (ISM) are briefly discussed. PMID:26688710

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

NASA Astrophysics Data System (ADS)

Zhang, Guizhai; Diao, Youjiang

2018-06-01

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

Composition and Integrity of PAHs, Nitro-PAHs, Hopanes and Steranes In Diesel Exhaust Particulate Matter.

PubMed

Huang, Lei; Bohac, Stanislav V; Chernyak, Sergei M; Batterman, Stuart A

2013-08-01

Diesel exhaust particulate matter contains many semivolatile organic compounds (SVOCs) of environmental and health significance. This study investigates the composition, emission rates, and integrity of 25 SVOCs, including polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs (NPAHs), and diesel biomarkers hopanes and steranes. Diesel engine particulate matter (PM), generated using an engine test bench, three engine conditions, and ultra-low sulfur diesel (ULSD), was collected on borosilicate glass fiber filters. Under high engine load, the PM emission rate was 0.102 g/kWh, and emission rate of ΣPAHs (10 compounds), ΣNPAHs (6 compounds), Σhopanes (2 compounds), and Σsteranes (2 compounds) were 2.52, 0.351, 0.02 ~ 2 and 1μg/kWh, respectively. Storage losses were evaluated for three cases: conditioning filters in clean air at 25 °C and 33% relative humidity (RH) for 24 h; storing filter samples (without extraction) wrapped in aluminum foil at 4 °C for up to one month; and storing filter extracts in glass vials capped with Teflon crimp seals at 4 °C for up to six months. After conditioning filters for 24 h, 30% of the more volatile PAHs were lost, but lower volatility NPAHs, hopanes and steranes showed negligible changes. Storing wrapped filters and extracts at 4 °C for up to one month did not lead to significant losses, but storing extracts for five months led to significant losses of PAHs and NPAHs; hopanes and steranes demonstrated greater integrity. These results suggest that even relatively brief filter conditioning periods, needed for gravimetric measurements of PM mass, and extended storage of filter extracts can lead to underestimates of SVOC concentrations. Thus, SVOC sampling and analysis protocols should utilize stringent criteria and performance checks to identify and limit possible biases occurring during filter and extract processing.

Composition and Integrity of PAHs, Nitro-PAHs, Hopanes and Steranes In Diesel Exhaust Particulate Matter

PubMed Central

Huang, Lei; Bohac, Stanislav V.; Chernyak, Sergei M.; Batterman, Stuart A.

2013-01-01

Diesel exhaust particulate matter contains many semivolatile organic compounds (SVOCs) of environmental and health significance. This study investigates the composition, emission rates, and integrity of 25 SVOCs, including polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs (NPAHs), and diesel biomarkers hopanes and steranes. Diesel engine particulate matter (PM), generated using an engine test bench, three engine conditions, and ultra-low sulfur diesel (ULSD), was collected on borosilicate glass fiber filters. Under high engine load, the PM emission rate was 0.102 g/kWh, and emission rate of ΣPAHs (10 compounds), ΣNPAHs (6 compounds), Σhopanes (2 compounds), and Σsteranes (2 compounds) were 2.52, 0.351, 0.02 ~ 2 and 1μg/kWh, respectively. Storage losses were evaluated for three cases: conditioning filters in clean air at 25 °C and 33% relative humidity (RH) for 24 h; storing filter samples (without extraction) wrapped in aluminum foil at 4 °C for up to one month; and storing filter extracts in glass vials capped with Teflon crimp seals at 4 °C for up to six months. After conditioning filters for 24 h, 30% of the more volatile PAHs were lost, but lower volatility NPAHs, hopanes and steranes showed negligible changes. Storing wrapped filters and extracts at 4 °C for up to one month did not lead to significant losses, but storing extracts for five months led to significant losses of PAHs and NPAHs; hopanes and steranes demonstrated greater integrity. These results suggest that even relatively brief filter conditioning periods, needed for gravimetric measurements of PM mass, and extended storage of filter extracts can lead to underestimates of SVOC concentrations. Thus, SVOC sampling and analysis protocols should utilize stringent criteria and performance checks to identify and limit possible biases occurring during filter and extract processing. PMID:24363468

Cloud deposition of PAHs at Mount Lushan in southern China.

PubMed

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

2015-09-01

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

The PAH Emission Characteristics of the Reflection Nebula NGC 2023

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

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

Grafted cellulose for PAHs removal present in industrial discharge waters

NASA Astrophysics Data System (ADS)

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

2014-05-01

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

Recombination Rates of Electrons with Interstellar PAH Molecules

NASA Technical Reports Server (NTRS)

Ballester, Jorge (Cartographer)

1996-01-01

The goal of this project is to develop a general model for the recombination of electrons with PAH molecules in an interstellar environment. The model is being developed such that it can be applied to a small number of families of PAHs without reference to specific molecular structures. Special attention will be focused on modeling the approximately circular compact PAHs in a way that only depends on the number of carbon atoms.

Polycyclic aromatic hydrocarbons (PAHs) from coal combustion: emissions, analysis, and toxicology.

PubMed

Liu, Guijian; Niu, Zhiyuan; Van Niekerk, Daniel; Xue, Jian; Zheng, Liugen

2008-01-01

Coal may become more important as an energy source in the 21st century, and coal contains large quantities of organic and inorganic matter. When coal burns chemical and physical changes take place, and many toxic compounds are formed and emitted. Polycyclic aromatic hydrocarbons (PAHs) are among those compounds formed and are considered to pose potential health hazards because some PAHs are known carcinogens. Based on their toxicology, 16 PAHs are considered as priority pollutants by the USEPA. More attention must be given to the various methods of extraction and analysis of PAH from coal or coal products to accurately explain and determine the species of PAHs. The influences of the extraction time, solvents, and methods for PAH identification are important. In the future, more methods and influences will be studied more carefully and widely. PAHs are environmental pollutants, are highly lipid soluble, and can be absorbed by the lungs, gut, and skin of mammals because they are associated with fine particles from coal combustion. More attention is being given to PAHs because of their carcinogenic and mutagenic action. We suggest that when using a coal stove indoors, a chimney should be used; the particles and gas containing PAHs should be released outdoors to reduce the health hazard, especially in Southwest China. During coal utilization processes, such as coal combustion and pyrolysis, PAHs released may be divided into two categories according to their formation pathways: one pathway is derived from complex chemical reactions and the other is from free PAHs transferred from the original coal. The formation and emission of PAHs is a complex physical and chemical process that has received considerable attention in recent years. It is suggested that the formation mechanisms of PAHs will be an increasingly important topic for researchers to find methods for controlling emissions during coal combustion.

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

PubMed

Košnář, Zdeněk; Mercl, Filip; Tlustoš, Pavel

2018-05-30

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

The Occurrence of 16 EPA PAHs in Food – A Review

PubMed Central

Zelinkova, Zuzana; Wenzl, Thomas

2015-01-01

Occurrence and toxicity of polycyclic aromatic hydrocarbons (PAHs) have been extensively studied in countries all over the world. PAHs generally occur in complex mixtures which may consist of hundreds of compounds. The U.S. Environmental Protection Agency (EPA) proposed in the 1970 to monitor a set of 16 PAHs which are frequently found in environmental samples. This article reviews the suitability of the 16 EPA PAHs for the assessment of potential health threats to humans stemming from the exposure to PAHs by food ingestion. It presents details on analysis methods, the occurrence of PAHs in food, regulatory aspects, and related risk management approaches. In addition, consideration is given to newer evaluations of the toxicity of PAHs and the requirements for risk assessment and management stemming from them. PMID:26681897

Solubilization, Solution Equilibria, and Biodegradation of PAH's under Thermophilic Conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Viamajala, S.; Peyton, B. M.; Richards, L. A.

Biodegradation rates of PAHs are typically low at mesophilic conditions and it is believed that the kinetics of degradation is controlled by PAH solubility and mass transfer rates. Solubility tests were performed on phenanthrene, fluorene and fluoranthene at 20 C, 40 C and 60 C and, as expected, a significant increase in the equilibrium solubility concentration and of the rate of dissolution of these polycyclic aromatic hydrocarbons (PAHs) was observed with increasing temperature. A first-order model was used to describe the PAH dissolution kinetics and the thermodynamic property changes associated with the dissolution process (enthalpy, entropy and Gibb's free energymore » of solution) were evaluated. Further, other relevant thermodynamic properties for these PAHs, including the activity coefficients at infinite dilution, Henry's law constants and octanol-water partition coefficients, were calculated in the temperature range 20-60 C. In parallel with the dissolution studies, three thermophilic Geobacilli were isolated from compost that grew on phenanthrene at 60 C and degraded the PAH more rapidly than other reported mesophiles. Our results show that while solubilization rates of PAHs are significantly enhanced at elevated temperatures, the biodegradation of PAHs under thermophilic conditions is likely mass transfer limited due to enhanced degradation rates.« less

Imaging of the PAH Emission Bands in the Orion Bar

NASA Technical Reports Server (NTRS)

Bregman, Jesse; Harker, David; Rank, David; Temi, Pasqiale; Morrison, David (Technical Monitor)

1994-01-01

The infrared spectrum of many planetary nebulae, HII regions, galactic nuclei, reflection nebulae, and WC stars are dominated by a set of narrow and broad features which for many years were called the "unidentified infrared bands". These bands have been attributed to several carbon-rich molecular species which all contain only carbon and hydrogen atoms, and fall into the class of PAH molecules or are conglomerates of PAH skeletons. If these bands are from PAHs, then PAHs contain 1-10% of the interstellar carbon, making them the most abundant molecular species in the interstellar medium after CO. From ground based telescopes, we have studied the emission bands assigned to C-H bond vibrations in PAHs (3.3, 11.3 microns) in the Orion Bar region, and showed that their distribution and intensities are consistent with a quantitative PAH model. We have recently obtained spectral images of the Orion Bar from the KAO at 6.2 and 7.7 microns using a 128 x 128 Si:Ga array camera in order to study the C-C modes of the PAH molecules. We will show these new data along with our existing C-H mode data set, and make a quantitative comparison of the data with the existing PAH model.

Are urinary PAHs biomarkers of controlled exposure to diesel exhaust?

PubMed Central

Lu, Sixin S.; Sobus, Jon R.; Sallsten, Gerd; Albin, Maria; Pleil, Joachim D.; Gudmundsson, Anders; Madden, Michael C.; Strandberg, Bo; Wierzbicka, Aneta; Rappaport, Stephen M.

2016-01-01

Urinary polycyclic aromatic hydrocarbons (PAHs) were evaluated as possible biomarkers of exposure to diesel exhaust (DE) in two controlled-chamber studies. We report levels of 14 PAHs from 28 subjects in urine that were collected before, immediately after and the morning after exposure. Using linear mixed-effects models, we tested for effects of DE exposure and several covariates (time, age, gender and urinary creatinine) on urinary PAH levels. DE exposures did not significantly alter urinary PAH levels. We conclude that urinary PAHs are not promising biomarkers of short-term exposures to DE in the range of 106–276 μg/m3. PMID:24754404

PAH Emission in the Orion Bar

NASA Technical Reports Server (NTRS)

Bregman, Jesse; Sloan, G. C.

1996-01-01

The emission from polycyclic aromatic hydrocarbons (PAH's) in the Orion Bar region is investigated using a combination of narrow-band imaging and long-slit spectroscopy. The goal was to study how the strength of the PAH bands vary with spatial position in this edge-on photo-dissociation region. The specific focus here is how these variations constrain the carrier of the 3.4 micron band.

Surface water polycyclic aromatic hydrocarbons (PAH) in urban areas of Nanjing, China.

PubMed

Wang, Chunhui; Zhou, Shenglu; Wu, Shaohua; Song, Jing; Shi, Yaxing; Li, Baojie; Chen, Hao

2017-10-01

The concentration, sources and environmental risks of polycyclic aromatic hydrocarbons (PAHs) in surface water in urban areas of Nanjing were investigated. The range of ∑ 16 PAHs concentration is between 4,076 and 29,455 ng/L, with a mean of 17,212 ng/L. The composition of PAHs indicated that 2- and 3-ring PAHs have the highest proportion in all PAHs, while the 5- and 6-ring PAHs were the least in proportion. By diagnostic ratio analysis, combustion and petroleum were a mixture input that contributed to the water PAH in urban areas of Nanjing. Positive matrix factorization quantitatively identified four factors, including coke oven, coal combustion, oil source, and vehicle emission, as the main sources. Toxic equivalency factors of BaP (BaP eq ) evaluate the environmental risks of PAHs and indicate the PAH concentration in surface water in urban areas of Nanjing had been polluted and might cause potential environmental risks. Therefore, the PAH contamination in surface water in urban areas of Nanjing should draw considerable attention.

LABORATORY PHOTO-CHEMISTRY OF PAHs: IONIZATION VERSUS FRAGMENTATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhen, Junfeng; Castellanos, Pablo; Ligterink, Niels

2015-05-01

Interstellar polycyclic aromatic hydrocarbons (PAHs) are expected to be strongly processed by vacuum ultraviolet photons. Here, we report experimental studies on the ionization and fragmentation of coronene (C{sub 24}H{sub 12}), ovalene (C{sub 32}H{sub 14}) and hexa-peri-hexabenzocoronene (HBC; C{sub 42}H{sub 18}) cations by exposure to synchrotron radiation in the range of 8–40 eV. The results show that for small PAH cations such as coronene, fragmentation (H-loss) is more important than ionization. However, as the size increases, ionization becomes more and more important and for the HBC cation, ionization dominates. These results are discussed and it is concluded that, for large PAHs,more » fragmentation only becomes important when the photon energy has reached the highest ionization potential accessible. This implies that PAHs are even more photo-stable than previously thought. The implications of this experimental study for the photo-chemical evolution of PAHs in the interstellar medium are briefly discussed.« less

Biochar accelerates PAHs biodegradation in petroleum-polluted soil by biostimulation strategy.

PubMed

Kong, Lulu; Gao, Yuanyuan; Zhou, Qixing; Zhao, Xuyang; Sun, Zhongwei

2018-02-05

Sawdust and wheat straw biochars prepared at 300°C and 500°C were applied to petroleum-polluted soil for an 84-day incubation to estimate their effectiveness on polycyclic aromatic hydrocarbons (PAHs) removal. Biochars alone were most effective at reducing PAHs contents. However, adding biochar to soils in company with NaN 3 solution resulted in a decreasing trend in terms of PAHs removal, which was even lower than treatment CK without biochar. Moreover, it was discovered by PCR-DGGE files and sequencing analysis that the predominant bacterial diversity slightly decreased but the abundance of some specific taxa, including PAHs degraders, was promoted with biochar input. These results highlighted the potential of biochar application on accelerating PAHs biodegradation, which could be attributed to the properties of biochars that benefit for making the amended soil a better habitat for microbes. The impacts of biochar preparation and pollutants nature on PAHs removal were also determined. Significant reduction in the PAHs contents was detected when adding biochar prepared at a high temperature (500°C), while the feedstocks of biochar showed little effect on PAHs removal. Due to the high hydrophobicity of aromatic rings, high-molecular weight PAHs were found much more resistant to microbial degradation in comparison with low-molecular weight PAHs. Copyright © 2017 Elsevier B.V. All rights reserved.

Environmental distribution of PAHs in pine needles, soils, and sediments.

PubMed

Navarro-Ortega, Alícia; Ratola, Nuno; Hildebrandt, Alain; Alves, Arminda; Lacorte, Sílvia; Barceló, Damià

2012-03-01

The content of 16 polycyclic aromatic hydrocarbons (PAHs) was determined in 60 samples from three environmental matrices (soils, sediments, and pine needles) in an effort to assess their distribution on a river basin scale. A sampling campaign was carried out in 2006, selecting urban, industrial, and agricultural sampling sites along the northeast of Spain. Techniques used included pressurized liquid extraction and solid-liquid ultrasonic extraction followed by gas chromatography-electron impact ionization mass spectrometry. The mean total PAHs concentrations were 290 < 613 < 1,628 ng/g (dry weight) in pine needles, soil, and sediments, respectively. There is a good correspondence between the total concentration of soils and pine needles, as opposed to the levels between sediments and pine needles. The high concentrations found in some Pinus halepensis samples may reflect a superior uptake potential of this species in comparison to the others studied. The three matrices present a very different PAH distribution pattern, with pine needles showing a predominance of the lighter (2-, 3-, and 4-ring) PAHs, whereas 5- and 6-ring PAHs are the most abundant in soils. Sediments display a more heterogeneous pattern, with contributions of all the PAHs but different distribution depending on the site, suggesting a wider range of input sources. Established PAH molecular ratios and principal component analysis were used to identify the origins and profiles of PAHs. While sediments showed a wide range attributed to historical inputs, soils and pine needles confirmed the compartmentalization of the PAHs, with lighter airborne PAHs accumulated in pine needles and heavier ones in soils. It can be suggested that the monitoring of several matrices is a strong tool to elucidate the contamination sources and accumulation patterns of PAHs. However, given the influence of the matrix type on this assessment, the information should be considered complementary, yet allowing a more

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

PubMed

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

2002-11-15

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

Evidence for the Presence of Hn-PAHs in Post AGB Stars

NASA Technical Reports Server (NTRS)

Materese, Christopher K.; Bregman, Jesse D.; Sandford, Scott A.

2017-01-01

Polycyclic aromatic hydrocarbons (PAHs) are believed to be ubiquitous in space therefore represent an important class of molecules for the field of astrochemistry. PAHs are relatively stable under interstellar conditions, account for a significant fraction of the known Universe's molecular carbon inventory, and are believed responsible for numerous telltale interstellar infrared emission bands. PAHs can be subdivided into numerous classes, one of which is Hydrogenated PAHs (Hn-PAHs). Hn-PAHs are multi-ringed partially aromatic compounds with excess hydrogenation, leading to a partial disruption of the aromatic system. The infrared spectra of these compounds produce telltale signatures that make them distinct from ordinary aromatic or aliphatic molecules (or a mixture of both). Hn-PAHs may be an important subclass of PAHs that could explain the spectra of some astronomical objects with anomalously large 3.4 micron features. The 3.4 micron feature observed in these objects may be associated with the aliphatic C-H stretching vibrations of the excess hydrogen. If this presumption is correct, we also expect to observe methylene scissoring modes at 6.9 microns. We have recently conducted a series of follow-up observations to compliment our laboratory experiments into the properties of Hn-PAHs. Here we present our laboratory and observational results in support of the hypothesis that Hn-PAHs are a viable candidate molecule as the emission source for numerous post-asymptotic giant branch objects with abnormally large 3.4 micron features.

Dissolved oxygen saturation controls PAH biodegradation in freshwater estuary sediments.

PubMed

Boyd, T J; Montgomery, M T; Steele, J K; Pohlman, J W; Reatherford, S R; Spargo, B J; Smith, D C

2005-02-01

Polycyclic aromatic hydrocarbons (PAHs) are common contaminants in terrestrial and aquatic environments and can represent a significant constituent of the carbon pool in coastal sediments. We report here the results of an 18-month seasonal study of PAH biodegradation and heterotrophic bacterial production and their controlling biogeochemical factors from 186 sediment samples taken in a tidally influenced freshwater estuary. For each sampling event, measurements were averaged from 25-45 stations covering approximately 250 km(2). There was a clear relationship between bacterial production and ambient temperature, but none between production and bottom water dissolved oxygen (DO) % saturation or PAH concentrations. In contrast with other studies, we found no effect of temperature on the biodegradation of naphthalene, phenanthrene, or fluoranthene. PAH mineralization correlated with bottom water DO saturation above 70% (r(2) > 0.99). These results suggest that the proportional utilization of PAH carbon to natural organic carbon is as much as three orders of magnitude higher during cooler months, when water temperatures are lower and DO % saturation is higher. Infusion of cooler, well-oxygenated water to the water column overlying contaminated sediments during the summer months may stimulate PAH metabolism preferentially over non-PAH organic matter.

PAH concentrations simulated with the AURAMS-PAH chemical transport model over Canada and the USA

NASA Astrophysics Data System (ADS)

Galarneau, E.; Makar, P. A.; Zheng, Q.; Narayan, J.; Zhang, J.; Moran, M. D.; Bari, M. A.; Pathela, S.; Chen, A.; Chlumsky, R.

2014-04-01

The offline Eulerian AURAMS (A Unified Regional Air quality Modelling System) chemical transport model was adapted to simulate airborne concentrations of seven PAHs (polycyclic aromatic hydrocarbons): phenanthrene, anthracene, fluoranthene, pyrene, benz[a]anthracene, chrysene + triphenylene, and benzo[a]pyrene. The model was then run for the year 2002 with hourly output on a grid covering southern Canada and the continental USA with 42 km horizontal grid spacing. Model predictions were compared to ~5000 24 h-average PAH measurements from 45 sites, most of which were located in urban or industrial areas. Eight of the measurement sites also provided data on particle/gas partitioning which had been modelled using two alternative schemes. This is the first known regional modelling study for PAHs over a North American domain and the first modelling study at any scale to compare alternative particle/gas partitioning schemes against paired field measurements. The goal of the study was to provide output concentration maps of use to assessing human inhalation exposure to PAHs in ambient air. Annual average modelled total (gas + particle) concentrations were statistically indistinguishable from measured values for fluoranthene, pyrene and benz[a]anthracene whereas the model underestimated concentrations of phenanthrene, anthracene and chrysene + triphenylene. Significance for benzo[a]pyrene performance was close to the statistical threshold and depended on the particle/gas partitioning scheme employed. On a day-to-day basis, the model simulated total PAH concentrations to the correct order of magnitude the majority of the time. The model showed seasonal differences in prediction quality for volatile species which suggests that a missing emission source such as air-surface exchange should be included in future versions. Model performance differed substantially between measurement locations and the limited available evidence suggests that the model's spatial resolution was too

Nitration of particle-associated PAHs and their derivatives (nitro-, oxy-, and hydroxy-PAHs) with NO 3 radicals

NASA Astrophysics Data System (ADS)

Zhang, Yang; Yang, Bo; Gan, Jie; Liu, Changgeng; Shu, Xi; Shu, Jinian

2011-05-01

The heterogeneous reactions of typical polycyclic aromatic hydrocarbons (PAHs) and their derivatives (nitro-, oxy-, and hydroxy-PAHs) adsorbed on azelaic acid particles with NO 3 radicals are investigated using a flow-tube reactor coupled to a vacuum ultraviolet photoionization aerosol time-of-flight mass spectrometer (VUV-ATOFMS). The mono-nitro-, di-nitro-, and poly-nitro-products from successive nitro-substitution reactions of PAHs and their derivatives are observed in real time with VUV-ATOFMS. 9-Nitroanthracene, anthraquinone, anthrone, 9,10-dinitroanthracene, 2-, 4-, and 9-nitrophenanthrene, 1-nitropyrene, 1,3-, 1,6-, and 1,8-dinitropyrene, 7-nitrobenzo[ a]anthracene, and benzo[ a]anthracene-7,12-dione are identified by GC/MS analysis of the reaction products of PAHs and their derivatives coated on the inner bottom surface of the conical flasks with NO 3 radicals. Other oxygenated products are tentatively assigned. 1-Nitropyrene is the only mono-nitrated product detected in the reaction of surface-bound pyrene with gas-phase NO 3 radicals. This phenomenon is different from what has been observed in previous studies of the gas-phase pyrene nitration, showing that 2-nitropyrene is the sole nitration product. The experimental results may reveal the discrepancies between the heterogeneous and homogeneous nitrations of pyrene.

Response of PAH-degrading genes to PAH bioavailability in the overlying water, suspended sediment, and deposited sediment of the Yangtze River.

PubMed

Xia, Xinghui; Xia, Na; Lai, Yunjia; Dong, Jianwei; Zhao, Pujun; Zhu, Baotong; Li, Zhihuang; Ye, Wan; Yuan, Yue; Huang, Junxiong

2015-06-01

The degrading genes of hydrophobic organic compounds (HOCs) serve as indicators of in situ HOC degradation potential, and the existing forms and bioavailability of HOCs might influence the distribution of HOC-degrading genes in natural waters. However, little research has been conducted to study the relationship between them. In the present study, nahAc and nidA genes, which act as biomarkers for naphthalene- and pyrene-degrading bacteria, were selected as model genotypes to investigate the response of polycyclic aromatic hydrocarbon (PAH)-degrading genes to PAH bioavailability in the overlying water, suspended sediment (SPS), and deposited sediment of the Yangtze River. The freely dissolved concentration, typically used to reflect HOC bioavailability, and total dissolved, as well as sorbed concentrations of PAHs were determined. Phylogenetic analysis showed that all the PAH-ring hydroxylating dioxygenase gene sequences of Gram-negative bacteria (PAH-RHD[GN]) were closely related to nahAc, nagAc, nidA, and uncultured PAH-RHD genes. The PAH-RHD[GN] gene diversity as well as nahAc and nidA gene copy numbers decreased in the following order: deposited sediment>SPS>overlying water. The nahAc and nidA gene abundance was not significantly correlated with environmental parameters but was significantly correlated with the bioavailable existing forms of naphthalene and pyrene in the three phases. The nahAc gene copy numbers in the overlying water and deposited sediment were positively correlated with freely dissolved naphthalene concentrations in the overlying and pore water phases, respectively, and so were nidA gene copy numbers. This study suggests that the distribution and abundance of HOC-degrading bacterial population depend on the HOC bioavailability in aquatic environments. Copyright © 2015 Elsevier Ltd. All rights reserved.

Annual variability of PAH concentrations in the Potomac River watershed

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maher, I.L.; Foster, G.D.

1995-12-31

Dynamics of organic contaminant transport in a large river system is influenced by annual variability in organic contaminant concentrations. Surface runoff and groundwater input control the flow of river waters. They are also the two major inputs of contaminants to river waters. The annual variability of contaminant concentrations in rivers may or may not represent similar trends to the flow changes of river waters. The purpose of the research is to define the annual variability in concentrations of polycyclic aromatic hydrocarbons (PAH) in riverine environment. To accomplish this, from March 1992 to March 1995 samples of Potomac River water weremore » collected monthly or bimonthly downstream of the Chesapeake Bay fall line (Chain Bridge) during base flow and main storm flow hydrologic conditions. Concentrations of selected PAHs were measured in the dissolved phase and the particulate phase via GC/MS. The study of the annual variability of PAH concentrations will be performed through comparisons of PAH concentrations seasonally, annually, and through study of PAH concentration river discharge dependency and rainfall dependency. For selected PAHs monthly and annual loadings will be estimated based on their measured concentrations and average daily river discharge. The monthly loadings of selected PAHs will be compared by seasons and annually.« less

Polycyclic aromatic hydrocarbons (PAHs) in atmospheric PM2.5 and PM10 at a coal-based industrial city: Implication for PAH control at industrial agglomeration regions, China

NASA Astrophysics Data System (ADS)

Wu, Di; Wang, Zongshuang; Chen, Jianhua; Kong, Shaofei; Fu, Xiao; Deng, Hongbing; Shao, Guofan; Wu, Gang

2014-11-01

Eighteen polycyclic aromatic hydrocarbons (PAHs) in PM2.5 and PM10 are identified and quantified at five sites of E'erduosi in 2005 by GC-MS. Total PAH concentrations in PM2.5 and PM10 are in the ranges of 0.58-145.01 ng m- 3 and 5.80-180.32 ng m- 3 for the five sites, decreasing as coal-chemical base site (ZGE) > heavy industrial site (QPJ) > residential site with heavy traffic (DS) > suburban site surrounded by grassland (HJQ) > background site (QGN) for both PM2.5 and PM10. PAH concentrations in the coal-chemical base site are 250 and 31.1 times of those in the background site. Flu, Pyr, Chr, BbF, BeP, IND and BghiP are abundant for the coal-chemical base site, totally accounting for 75% of the PAH concentrations. 4, 5 and 6 rings PAHs are dominant, accounting for 88.9-94.2% and 90.5-94.1% of PAHs in PM2.5 and PM10, respectively. Combustion-derived PAH concentrations cover 42%-84% and 75%-82% of PAHs in PM2.5 and PM10, indicating large amounts of combustion sources existed for them in E'erduosi. PAH compositions between PM2.5 and PM10 are quite different from each other for sites with few human activities (HJQ and QGN) by coefficient of divergence analysis. Results obtained from principal component analysis and diagnostic ratios indicate that coal combustion, vehicle emission, wood combustion and industrial processes are the main sources for PAHs in E'erduosi. According to BaP equivalent concentration, the potential health risk of PAHs in PM2.5 at the two industrial sites ZGE and QPJ are 537 and 460 times of those for the background site. And they are 4.3 and 3.7 times of those for the residential site. The potential PAH pollution in particles at other industrial agglomeration regions that occurred in China in recent years should be paid attention by the local government.

PAH concentrations simulated with the AURAMS-PAH chemical transport model over Canada and the USA

NASA Astrophysics Data System (ADS)

Galarneau, E.; Makar, P. A.; Zheng, Q.; Narayan, J.; Zhang, J.; Moran, M. D.; Bari, M. A.; Pathela, S.; Chen, A.; Chlumsky, R.

2013-07-01

The off-line Eulerian AURAMS chemical transport model was adapted to simulate the atmospheric fate of seven PAHs: phenanthrene, anthracene, fluoranthene, pyrene, benz[a]anthracene, chrysene + triphenylene, and benzo[a]pyrene. The model was then run for the year 2002 with hourly output on a~grid covering southern Canada and the continental USA with 42 km horizontal grid spacing. Model predictions were compared to ~ 5000 24 h average PAH measurements from 45 sites, eight of which also provided data on particle/gas partitioning which had been modelled using two alternative schemes. This is the first known regional modelling study for PAHs over a North American domain and the first modelling study at any scale to compare alternative particle/gas partitioning schemes against paired field measurements. Annual average modelled total (gas + particle) concentrations were statistically indistinguishable from measured values for fluoranthene, pyrene and benz[a]anthracene whereas the model underestimated concentrations of phenanthrene, anthracene and chrysene + triphenylene. Significance for benzo[a]pyrene performance was close to the statistical threshold and depended on the particle/gas partitioning scheme employed. On a day-to-day basis, the model simulated total PAH concentrations to the correct order of magnitude the majority of the time. Model performance differed substantially between measurement locations and the limited available evidence suggests that the model spatial resolution was too coarse to capture the distribution of concentrations in densely populated areas. A more detailed analysis of the factors influencing modelled particle/gas partitioning is warranted based on the findings in this study.

Toxicity and photoactivation of PAH mixtures in marine sediment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Swartz, R.; Ferraro, S.; Lamberson, J.

1995-12-31

The toxicity and toxicological photoactivation of mixtures of sediment-associated fluoranthene, phenanthrene, pyrene, and acenaphthene were determined using standard 10 d sediment toxicity tests with the marine amphipod, Rhepoxynius abronius. The four PAHs were spiked into sediment in a concentration series of either single compounds or an equitoxic mixture. Spiked sediment was stored at 4 C for 28 d before testing. Toxicity tests were conducted under fluorescent lighting. Survivors after 10 d in PAH-contaminated sediment were exposed for 1 h to UV light in the absence of sediment and then tested for their ability to bury in clean sediment. The 10more » d LC50s for single PAHs were 3.3, 2.2, 2.8, and 2.3 mg/g oc for fluoranthene, phenanthrene, pyrene, and acenaphthene, respectively. These LC50s were used to calculate the sum of toxic units ({Sigma}TU) of the four PAHs in the equitoxic mixture treatments. The {Sigma}TU LC50 was then calculated for the mixture treatments. If the toxicological interaction of the four PAHs in the mixture was additive, the {Sigma}TU LC50 should equal 1.0. The observed {Sigma}TU LC50 in the mixture was 1.55, indicating the interaction was slightly less than additive. UV enhancement of toxic effects of individual PAHs was correctly predicted by photophysical properties, i.e. pyrene and fluoranthene were photoactivated and phenanthrene and acenaphthene were not. UV effects in the mixture of four PAHs can be explained by the photoactivation of pyrene and fluoranthene alone.« less

PAH Emission From ULIRGs: Evidence For Unusual Grain Properties?

NASA Astrophysics Data System (ADS)

Marshall, Jason A.; Armus, L.; Spoon, H. W. W.

2007-12-01

The tremendous power emerging from ultraluminous infrared galaxies (ULIRGs) is driven both by high levels of star-formation activity and AGN-related accretion. Observations of star-forming regions in the Milky Way and external star-forming galaxies provide evidence that the first of these energy generation mechanisms often also gives rise to emission from PAH molecules in the form of characteristic mid-IR features. Given the composite nature of ULIRGs, it is not surprising that many also exhibit significant emission from PAHs. Perhaps more surprising, however, is that some ULIRGs believed to be powered primarily by AGNs also show emission from PAHs, although typically at lower levels relative to their total dust output. To investigate the nature of the PAH emission from galaxies powered either by star-formation or AGN accretion alone, as well as emission from composite systems such as ULIRGs powered by both mechanisms, we present a detailed study of the PAH emission spectra from galaxies of each type. We use the CAFE spectral energy distribution decomposition software we have developed to derive and extinction correct the spectra of PAH emission from a sample of 100 galaxies with Spitzer/IRS observations, and use the results of this analysis to calculate the ratios of the various mid-IR PAH feature luminosities. In particular, we investigate to what extent these relative feature strengths vary as a function of the optical classification of galaxies, and we inquire into whether or not the derived feature strength ratios provide evidence for unusual grain properties in the extreme conditions within ULIRGs.

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

NASA Astrophysics Data System (ADS)

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

2017-12-01

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous group of organic pollutants, some of which are known to be toxic, and/or carcinogenic to humans. The major source of these PAHs into the northern Gulf of Mexico (NGOM) are Mississippi River discharge, coastal erosion, atmospheric deposition, and numerous natural oil seeps and spills. In addition to these background source of PAHs, the Deepwater Horizon (DWH) oil spill in 2010 added 21,000 tons of PAHs into the NGOM water. In this study, we measured PAHs distribution and accumulation rates in coastal sediments near the Mississippi River mouth in 2011 and 2015 to understand the effect of DWH oil spill in PAHs accumulation in coastal sediments. Sediment cores were collected and sliced at 1 cm interval to measure PAHs concentration, and to estimate 210Pb-based sedimentation and the PAHs' accumulation rates. The results showed that the sediment deposition rates in this region varied between 0.5 to 0.9 cm/yr. The results also showed that the concentration of total PAHs (ΣPAH43) and their accumulation rates vary between 68 - 100 ng g-1 and 7 - 160 ng cm-2 yr-1, respectively. While the PAHs accumulation rate in coastal sediment varied over the years, there is no significant variation in PAHs accumulation rate before and after the DWH oil spill.

Primary sources and toxicity of PAHs in Milwaukee-area streambed sediment

USGS Publications Warehouse

Baldwin, Austin K.; Corsi, Steven R.; Lutz, Michelle A.; Ingersoll, Christopher G.; Dorman, Rebecca A.; Magruder, Christopher; Magruder, Matthew

2017-01-01

High concentrations of polycyclic aromatic hydrocarbons (PAHs) in streams can be a significant stressor to aquatic organisms. To understand the likely sources and toxicity of PAHs in Milwaukee-area streams, streambed sediment samples from 40 sites and parking lot dust samples from 6 sites were analyzed for 38 parent PAHs and 25 alkylated PAHs. Diagnostic ratios, profile correlations, principal components analysis, source-receptor modeling, and mass fractions analysis were used to identify potential PAH sources to streambed sediment samples, and land-use analysis was used to relate streambed sediment PAH concentrations to different urban-related land uses. On the basis of this multiple lines-of-evidence approach, coal-tar pavement sealant was indicated as the primary source of PAHs in a majority of streambed sediment samples, contributing an estimated 77% of total PAHs to samples, on average. Comparison to the Probable Effect Concentrations and (or) the Equilibrium Partitioning Sediment Benchmark indicates that 78% of stream sediment samples are likely to cause adverse effects to benthic organisms. Laboratory toxicity tests on a 16-sample subset of the streambed sites using the amphipod Hyalella azteca (28-day) and the midge Chironomus dilutus (10-day) measured significant reductions in one or more biological endpoints, including survival, in 75% of samples, with H. azteca more responsive than C. dilutus.

Co-formation and co-release of genotoxic PAHs, alkyl-PAHs and soot nanoparticles from gasoline direct injection vehicles

NASA Astrophysics Data System (ADS)

Muñoz, Maria; Haag, Regula; Honegger, Peter; Zeyer, Kerstin; Mohn, Joachim; Comte, Pierre; Czerwinski, Jan; Heeb, Norbert V.

2018-04-01

Gasoline direct injection (GDI) vehicles quickly replace traditional port-fuel injection (PFI) vehicles in Europe reaching about 50 million vehicles on roads in 2020. GDI vehicles release large numbers of soot nanoparticles similar to conventional diesel vehicles without particle filters. These exhausts will increasingly affect air quality in European cities. We hypothesized that such particles are released together with polycyclic aromatic hydrocarbons (PAHs) formed under the same combustion conditions. Emission data of a fleet of 7 GDI vehicles (1.2-1.8 L) including Euro-3,-4,-5 and -6 technologies revealed substantial particle emissions on average of 2.5 × 1012 particles km-1 in the cold worldwide harmonized light vehicle test cycle (cWLTC), the future European legislative driving cycle. Particle emissions increased 2-3 orders of magnitude during acceleration like CO, indicating that transient driving produces fuel-rich conditions with intense particle formation. For comparison, an Euro-5 diesel vehicle (1.6 L) equipped with a particle filter released 3.9 × 1010 particles km-1 (cWLTC), clearly within the Euro-5/6 limit value of 6.0 × 1011 particles km-1 and 64-fold below the GDI fleet average. PAH and alkyl-PAH emissions of the GDI vehicles also exceeded those of the diesel vehicle. Mean GDI emissions of 2-, 3-, 4-, 5- and 6-ring PAHs in the cWLTC were 240, 44, 5.8, 0.5 and 0.4 μg km-1, those of the diesel vehicle were only 8.8, 7.1, 8.6, 0.02 and 0.02 μg km-1, respectively. Thus mean PAH emissions of the GDI fleet were 2 orders of magnitude higher than the bench mark diesel vehicle. A comparison of the toxicity equivalent concentrations (TEQ) in the cWLTC of the GDI fleet and the diesel vehicle revealed that GDI vehicles released 200-1700 ng TEQ m-3 genotoxic PAHs, being 6-40 times higher than the diesel vehicle with 45 ng TEQ km-1. The co-release of genotoxic PAHs adsorbed on numerous soot nanoparticles is critical due to the Trojan horse effect

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

PubMed

Bansal, Vasudha; Kim, Ki-Hyun

2015-11-01

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

A spatial approach to environmental risk assessment of PAH contamination.

PubMed

Bengtsson, Göran; Törneman, Niklas

2009-01-01

The extent of remediation of contaminated industrial sites depends on spatial heterogeneity of contaminant concentration and spatially explicit risk characterization. We used sequential Gaussian simulation (SGS) and indicator kriging (IK) to describe the spatial distribution of polycyclic aromatic hydrocarbons (PAHs), pH, electric conductivity, particle aggregate distribution, water holding capacity, and total organic carbon, and quantitative relations among them, in a creosote polluted soil in southern Sweden. The geostatistical analyses were combined with risk analyses, in which the total toxic equivalent concentration of the PAH mixture was calculated from the soil concentrations of individual PAHs and compared with ecotoxicological effect concentrations and regulatory threshold values in block sizes of 1.8 x 1.8 m. Most PAHs were spatially autocorrelated and appeared in several hot spots. The risk calculated by SGS was more confined to specific hot spot areas than the risk calculated by IK, and 40-50% of the site had PAH concentrations exceeding the threshold values with a probability of 80% and higher. The toxic equivalent concentration of the PAH mixture was dependent on the spatial distribution of organic carbon, showing the importance of assessing risk by a combination of measurements of PAH and organic carbon concentrations. Essentially, the same risk distribution pattern was maintained when Monte Carlo simulations were used for implementation of risk in larger (5 x 5 m), economically more feasible remediation blocks, but a smaller area became of great concern for remediation when the simulations included PAH partitioning to two separate sources, creosote and natural, of organic matter, rather than one general.

A Systematic Review of Paradoxical Adipose Hyperplasia (PAH) Post-Cryolipolysis.

PubMed

Ho, Derek; Jagdeo, Jared

2017-01-01

Body sculpting, or body contouring, is among the fastest growing areas in cosmetic dermatology. Cryolipolysis, or "fat freezing," was FDA-cleared (CoolSculpting System, ZELTIQ Aesthetics, Pleasanton, CA) initially in 2010 for fat removal of the anks, and subsequently received FDA-clearance for other anatomical locations. Over the past several years, there have been increasing published reports and physician discussion regarding paradoxical adipose hyperplasia (PAH) post-cryolipolysis, previously identified as a "rare" adverse effect. To review published reports of PAH post-cryolipolysis, expand on previously proposed hypothesis of PAH, and provide rec- ommendations for prevention and treatment of PAH. On July 26, 2016, we systematically searched the computerized medical bibliographic databases PubMed, EMBASE, Web of Science, and CINAHL with the search term "cryolipolysis." A total of 314 records were returned from our search terms and 10 records were found to be suitable for our review. We identi- ed a total of 16 cases of PAH post-cryolipolysis in the published literature. Based upon the published literature, we identi ed that the current incidence of PAH may be higher than previously re- ported. Although the pathoetiology of PAH is currently unknown, we hypothesize that some adipocytes may be "naturally selected" for survival due to their inherent tolerance to cryolipolysis. We believe that while cryolipolysis is an effective non-invasive treatment option for body contouring, physicians and patients should be aware of PAH as a potential adverse effect and treatment options. J Drugs Dermatol. 2017;16(1):62-67..

On the driving force of PAH production

NASA Technical Reports Server (NTRS)

Frenklach, Michael

1989-01-01

The kinetic factors affecting the production of polycyclic aromatic hydrocarbons (PAH) in high-temperature pyrolysis and combustion environments are analyzed. A lumped kinetic model representing polymerization-type growth by one irreversible step and two reversible steps is considered. It is shown that at high temperatures, PAH growth is controlled by the superequilibrium of hydrogen atoms; at low temperatures and low H2 concentrations, the PAH growth rate is proportional to the rate of the H-abstraction of a hydrogen atom from aromatic molecules; while at low temperatures and high H2 concentrations, it is controlled by the thermodynamics of the H-abstraction and the kinetics of acetylene addition to aromatic radicals. The presence of oxygen mainly affects the small-molecule reactions during the induction period.

PAH (Polycyclic Aromatic Hydrocarbon) bioaccumulation and PAHs/shell weight index in Ruditapes philippinarum (Adams & Reeve, 1850) from the Vallona lagoon (northern Adriatic Sea, NE Italy).

PubMed

Cacciatore, Federica; Bernarello, Valentina; Boscolo Brusà, Rossella; Sesta, Giulio; Franceschini, Gianluca; Maggi, Chiara; Gabellini, Massimo; Lamberti, Clauda Virno

2018-02-01

The Vallona lagoon is a transitional area located in the Po River delta (NE, ITALY) traditionally exploited for Manila clam (Ruditapes philippinarum) farming. During 2007-2008, a pipeline was buried in the middle of the lagoon to connect an off-shore structure to facilities on land. PAH levels were monitored in Manila clams and sediments before, during and after the pipeline construction to assess the impact of the activities through the pattern of distribution of the PAH compounds. PAH bioaccumulation in clams displayed seasonal fluctuations with higher levels in autumnal and wintry surveys than in spring-summer. Principal component analysis applied to PAHs in clams highlighted a petrogenic input during ante operam period and a pyrolytic origin during the burying activities. On the contrary, sediment PAH concentrations resulted quite similar both among sites and periods. Biota-Sediment-Accumulation-Factor values also confirmed that sediments were not the major source of PAH pollution for clams in this study. The welfare of clams was examined through two physiological indices (condition index and survival in air) to check the effects of the activities on a commercial resource. Both physiological indices exhibited seasonal variations connected to natural endogenous and exogenous factors; however survival in air was the most sensitive index in highlighting the effects of the pipeline burying activities. Finally, to ensure that PAH bioavailability assessment was not affected by seasonal variation of soft tissues of molluscs, PAHs/shell weight index was applied. Higher levels of this index were observed before and during the burying activities, whilst, after that, values significantly lowered. Moreover, the normalization enabled us to highlight the PAH uptake from clams in some particular periods and to compare different populations in a long-term biomonitoring program with data obtained from different periods of the year. Copyright © 2017 Elsevier Inc. All rights

Effect of a cationic surfactant on the volatilization of PAHs from soil.

PubMed

Lu, Li; Zhu, Lizhong

2012-06-01

Cationic surfactants are common in soils because of their use in daily cosmetic and cleaning products, and their use as a soil amendment for the mitigation and remediation of organic contaminated soils has been proposed. Such surfactant may affect the transfer and fate of organic contaminants in the environment. This study investigated the effect of a cationic surfactant, dodecylpyridinium bromide (DDPB), on the volatilization of polycyclic aromatic hydrocarbons (PAHs) from a paddy soil. The volatilization of PAHs from moist soil amended with different concentrations of DDPB was tested in an open system. The specific effects of DDPB on the liquid-vapor and solid-vapor equilibriums of PAHs were separately investigated in closed systems by headspace analysis. DDPB affects both liquid-vapor and solid-vapor processes of PAHs in soil. At DDPB concentrations below the critical micelle concentration (CMC), movement of PAHs from the bulk solution to the gas-liquid interface appeared to be facilitated by interaction between PAHs and the surfactant monomers adsorbed at the gas-liquid interface, promoting the volatilization of PAHs from solution. However, when DDPB was greater than the CMC, volatilization was inhibited due to the solubilization of PAHs by micelles. On the other hand, the formation of sorbed surfactant significantly inhibited the solid-vapor volatilization of PAHs. The overall effect of the two simultaneous effects of DDPB on liquid-vapor and solid-vapor processes was a decreased volatilization loss of PAHs from soil. Inhibition of PAH volatilization was more significant for the soil with a lower moisture content.

Polycyclic aromatic hydrocarbon (PAH) emissions from a coal-fired pilot FBC system.

PubMed

Liu, K; Han, W; Pan, W P; Riley, J T

2001-06-29

Due to the extensive amount of data suggesting the hazards of these compounds, 16 polycyclic aromatic hydrocarbons (PAHs) are on the Environmental Protection Agency (EPA) Priority Pollutant List. Emissions of these PAHs in the flue gas from the combustion of four coals were measured during four 1000h combustion runs using the 0.1MW heat-input (MWth) bench-scale fluidized bed combustor (FBC). An on-line sampling system was designed for the 16 PAHs, which consisted of a glass wool filter, condenser, glass fiber filter, Teflon filter, and a Tenax trap. The filters and Tenax were extracted by methylene chloride and hexane, respectively, followed by GC/MS analysis using the selective ion monitoring (SIM) mode. In this project, the effects of operating parameters, limestone addition, chlorine content in the coal, and Ca/S molar ratio on the emissions of PAHs were studied. The results indicated that the emissions of PAHs in an FBC system are primarily dependent on the combustion temperature and excess air ratio. The injection of secondary air with high velocity in the freeboard effectively reduces PAH emissions. The addition of extra limestone can promote the formation of PAHs in the FBC system. Chlorine in the coal can possibly lead to large benzene ring PAH formation during combustion. The total PAH emission increases with an increase in the sulfur content of coal. Incomplete combustion results in PAHs with four or more benzene rings. High efficiency combustion results in PAHs with two or three benzene rings.

Yeast Pah1p Phosphatidate Phosphatase Is Regulated by Proteasome-mediated Degradation*

PubMed Central

Pascual, Florencia; Hsieh, Lu-Sheng; Soto-Cardalda, Aníbal; Carman, George M.

2014-01-01

Yeast PAH1-encoded phosphatidate phosphatase is the enzyme responsible for the production of the diacylglycerol used for the synthesis of triacylglycerol that accumulates in the stationary phase of growth. Paradoxically, the growth phase-mediated inductions of PAH1 and phosphatidate phosphatase activity do not correlate with the amount of Pah1p; enzyme abundance declined in a growth phase-dependent manner. Pah1p from exponential phase cells was a relatively stable protein, and its abundance was not affected by incubation with an extract from stationary phase cells. Recombinant Pah1p was degraded upon incubation with the 100,000 × g pellet fraction of stationary phase cells, although the enzyme was stable when incubated with the same fraction of exponential phase cells. MG132, an inhibitor of proteasome function, prevented degradation of the recombinant enzyme. Endogenously expressed and plasmid-mediated overexpressed levels of Pah1p were more abundant in the stationary phase of cells treated with MG132. Pah1p was stabilized in mutants with impaired proteasome (rpn4Δ, blm10Δ, ump1Δ, and pre1 pre2) and ubiquitination (hrd1Δ, ubc4Δ, ubc7Δ, ubc8Δ, and doa4Δ) functions. The pre1 pre2 mutations that eliminate nearly all chymotrypsin-like activity of the 20 S proteasome had the greatest stabilizing effect on enzyme levels. Taken together, these results supported the conclusion that Pah1p is subject to proteasome-mediated degradation in the stationary phase. That Pah1p abundance was stabilized in pah1Δ mutant cells expressing catalytically inactive forms of Pah1p and dgk1Δ mutant cells with induced expression of DGK1-encoded diacylglycerol kinase indicated that alteration in phosphatidate and/or diacylglycerol levels might be the signal that triggers Pah1p degradation. PMID:24563465

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Ying, E-mail: echochen327@163.com; National Center of Solid Waste Management, Ministry of Environmental Protection, Beijing 100029; Zhao, Rongzhi

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

Characteristics and survival of adult Swedish PAH and CTEPH patients 2000-2014.

PubMed

Rådegran, Göran; Kjellström, Barbro; Ekmehag, Björn; Larsen, Flemming; Rundqvist, Bengt; Blomquist, Sofia Berg; Gustafsson, Carola; Hesselstrand, Roger; Karlsson, Monica; Kornhall, Björn; Nisell, Magnus; Persson, Liselotte; Ryftenius, Henrik; Selin, Maria; Ullman, Bengt; Wall, Kent; Wikström, Gerhard; Willehadson, Maria; Jansson, Kjell

2016-08-01

The Swedish Pulmonary Arterial Hypertension Register (SPAHR) is an open continuous register, including pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) patients from 2000 and onwards. We hereby launch the first data from SPAHR, defining baseline characteristics and survival of Swedish PAH and CTEPH patients. Incident PAH and CTEPH patients 2008-2014 from all seven Swedish PAH-centres were specifically reviewed. There were 457 PAH (median age: 67 years, 64% female) and 183 CTEPH (median age: 70 years, 50% female) patients, whereof 77 and 81%, respectively, were in functional class III-IV at diagnosis. Systemic hypertension, diabetes, ischaemic heart disease and atrial fibrillation were common comorbidities, particularly in those >65 years. One-, 3- and 5-year survival was 85%, 71% and 59% for PAH patients. Corresponding numbers for CTEPH patients with versus without pulmonary endarterectomy were 96%, 89% and 86% versus 91%, 75% and 69%, respectively. In 2014, the incidence of IPAH/HPAH, associated PAH and CTEPH was 5, 3 and 2 per million inhabitants and year, and the prevalence was 25, 24 and 19 per million inhabitants. The majority of the PAH and CTEPH patients were diagnosed at age >65 years, in functional class III-IV, and exhibiting several comorbidities. PAH survival in SPAHR was similar to other registers.

Enhanced PM10 bounded PAHs from shipping emissions

NASA Astrophysics Data System (ADS)

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

2015-05-01

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

Pore Water PAH Transport in Amended Sediment Caps

NASA Astrophysics Data System (ADS)

Gidley, P. T.; Kwon, S.; Ghosh, U.

2009-05-01

Capping is a common remediation strategy for contaminated sediments that creates a physical barrier between contaminated sediments and the water column. Diffusive flux of contaminants through a sediment cap is small. However, under certain hydrodynamic conditions such as groundwater potential and tidal pumping, groundwater advection can accelerate contaminant transport. Hydrophobic organic contaminants such as polycyclic aromatic hydrocarbons (PAHs) could be transported through the cap under advective conditions. To better understand PAH migration under these conditions, physical models of sediment caps were evaluated in the laboratory through direct measurement of pore water using solid phase micro-extraction with gas chromatography and mass spectrometry. Contaminated sediment and capping material was obtained from an existing Superfund site that was capped at Eagle Harbor, Washington. A PAH dissolution model linked to an advection-dispersion equation with retardation using published organic carbon-water partitioning coefficients (Koc) was compared to measured PAHs in the sediment and cap porewater of the physical model.

Accumulation of polycyclic aromatic hydrocarbons (PAHs) and oxygenated PAHs (OPAHs) in organic and mineral soil horizons from four U.S. remote forests.

PubMed

Obrist, Daniel; Zielinska, Barbara; Perlinger, Judith A

2015-09-01

We characterized distributions of 23 polycyclic aromatic hydrocarbons (Σ23PAH) and nine oxygenated PAHs (Σ9OPAH) in four remote forests. We observed highest Σ23PAH and Σ9OPAH concentrations in a coniferous forest in Florida, particularly in organic layers which we attributed to frequent prescribed burning. Across sites, Σ23PAH and Σ9OPAH concentrations strongly increased from surface to humidified organic layers (+1626%) where concentrations reached up to 584 ng g(-1). Concentrations in mineral soils were lower (average 37 ± 8 ng g(-1)); but when standardized per unit organic carbon (OC), PAH/OC and OPAH/OC ratios were at or above levels observed in organic layers. Accumulation in litter and soils (i.e., enrichment factors with depth) negatively correlated with octanol-water partition coefficients (Kow) and therefore was linked to water solubility of compounds. Concentrations of Σ9OPAHs ranged from 6 ± 6 ng g(-1) to 39 ± 25 ng g(-1) in organic layers, and from 3 ± 1 ng g(-1) to 11 ± 3 ng g(-1) in mineral soils, and were significantly and positively correlated to Σ23PAHs concentrations (r(2) of 0.90) across sites and horizons. While OPAH concentrations generally decreased from organic layers to mineral soil horizons, OPAH/OC ratios increased more strongly with depth compared to PAHs, in particular for anthrone, anthraquinone, fluorenone, and acenaphthenequinone. The strong vertical accumulation of OPAH relative to OC was exponentially and negatively correlated to C/N ratios (r(2)=0.67), a measure that often is used for tissue age. In fact, C/N ratios alone explained two-thirds of the variability in OPAH/OC ratios suggesting particularly high retention, sorption, and persistency of OPAHs in old, decomposed carbon fractions. Copyright © 2015 Elsevier Ltd. All rights reserved.

Biodegradation of PAHs and PCBs in soils and sludges

USGS Publications Warehouse

Liu, L.; Tindall, J.A.; Friedel, M.J.

2007-01-01

Results from a multi-year, pilot-scale land treatment project for PAHs and PCBs biodegradation were evaluated. A mathematical model, capable of describing sorption, sequestration, and biodegradation in soil/water systems, is applied to interpret the efficacy of a sequential active-passive biotreatment process of organic chemicals on remediation sites. To account for the recalcitrance of PAHs and PCBs in soils and sludges during long-term biotreatment, this model comprises a kinetic equation for organic chemical intraparticle sequestration process. Model responses were verified by comparison to measurements of biodegradation of PAHs and PCBs in land treatment units; a favorable match was found between them. Model simulations were performed to predict on-going biodegradation behavior of PAHs and PCBs in land treatment units. Simulation results indicate that complete biostabilization will be achieved when the concentration of reversibly sorbed chemical (S RA) reduces to undetectable levels, with a certain amount of irreversibly sequestrated residual chemical (S IA) remaining within the soil particle solid phase. The residual fraction (S IA) tends to lose its original chemical and biological activity, and hence, is much less available, toxic, and mobile than the "free" compounds. Therefore, little or no PAHs and PCBs will leach from the treatment site and constitutes no threat to human health or the environment. Biotreatment of PAHs and PCBs can be terminated accordingly. Results from the pilot-scale testing data and model calculations also suggest that a significant fraction (10-30%) of high-molecular-weight PAHs and PCBs could be sequestrated and become unavailable for biodegradation. Bioavailability (large K d , i.e., slow desorption rate) is the key factor limiting the PAHs degradation. However, both bioavailability and bioactivity (K in Monod kinetics, i.e., number of microbes, nutrients, and electron acceptor, etc.) regulate PCBs biodegradation. The sequential

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

PubMed

Karaca, Gizem

2016-02-01

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

Mechanism-based classification of PAH mixtures to predict carcinogenic potential

DOE PAGES

Tilton, Susan C.; Siddens, Lisbeth K.; Krueger, Sharon K.; ...

2015-04-22

We have previously shown that relative potency factors and DNA adduct measurements are inadequate for predicting carcinogenicity of certain polycyclic aromatic hydrocarbons (PAHs) and PAH mixtures, particularly those that function through alternate pathways or exhibit greater promotional activity compared to benzo[ a]pyrene (BaP). Therefore, we developed a pathway based approach for classification of tumor outcome after dermal exposure to PAH/mixtures. FVB/N mice were exposed to dibenzo[ def,p]chrysene (DBC), BaP or environmental PAH mixtures (Mix 1-3) following a two-stage initiation/promotion skin tumor protocol. Resulting tumor incidence could be categorized by carcinogenic potency as DBC>>BaP=Mix2=Mix3>Mix1=Control, based on statistical significance. Gene expression profilesmore » measured in skin of mice collected 12 h post-initiation were compared to tumor outcome for identification of short-term bioactivity profiles. A Bayesian integration model was utilized to identify biological pathways predictive of PAH carcinogenic potential during initiation. Integration of probability matrices from four enriched pathways (p<0.05) for DNA damage, apoptosis, response to chemical stimulus and interferon gamma signaling resulted in the highest classification accuracy with leave-one-out cross validation. This pathway-driven approach was successfully utilized to distinguish early regulatory events during initiation prognostic for tumor outcome and provides proof-of-concept for using short-term initiation studies to classify carcinogenic potential of environmental PAH mixtures. As a result, these data further provide a ‘source-to outcome’ model that could be used to predict PAH interactions during tumorigenesis and provide an example of how mode-of-action based risk assessment could be employed for environmental PAH mixtures.« less

Incidence of real-world automotive parent and halogenated PAH in urban atmosphere.

PubMed

Gao, Pan-Pan; Zhao, Yi-Bo; Ni, Hong-Gang

2018-06-01

This study reports results from a tunnel experiment impact of real-world traffic-related particle and gas parent and halogenated polycyclic aromatic hydrocarbons (PAHs and HPAHs) on urban air. The traffic related emission characteristics and subsequent environmental behavior of these compounds were investigated. To understand the significance of real-world transport emissions to the urban air, traffic-related mass emissions of PAHs and HPAHs were estimated based on measured emission factors. According to our results, PAHs and HPAHs emissions via particulate phase were greater than those via gaseous phase; particles in 2.1-3.3 μm size fraction, have the major contribution to particulate PAHs and HPAHs emissions. Over all, contribution of traffic-related emission of PAHs (only ∼3% of the total PAHs emission in China) is an overstated source of PAHs pollution in China. Actually, exhaust pipe emission contributed much less than the total traffic-related emission of pollutants. Copyright © 2018 Elsevier Ltd. All rights reserved.

The Charge State of Polycyclic Aromatic Hydrocarbons Across Reflection Nebulae: PAH Charge Balance and Calibration

NASA Astrophysics Data System (ADS)

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

2016-11-01

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

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boersma, C.; Bregman, J.; Allamandola, L. J., E-mail: Christiaan.Boersma@nasa.gov

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

Effect of Warfarin Treatment on Survival of Patients With Pulmonary Arterial Hypertension (PAH) in the Registry to Evaluate Early and Long-Term PAH Disease Management (REVEAL)

PubMed Central

Preston, Ioana R.; Roberts, Kari E.; Miller, Dave P.; Sen, Ginny P.; Selej, Mona; Benton, Wade W.; Hill, Nicholas S.

2015-01-01

Background— Long-term anticoagulation is recommended in idiopathic pulmonary arterial hypertension (IPAH). In contrast, limited data support anticoagulation in pulmonary arterial hypertension (PAH) associated with systemic sclerosis (SSc-PAH). We assessed the effect of warfarin anticoagulation on survival in IPAH and SSc-PAH patients enrolled in Registry to Evaluate Early and Long-term PAH Disease Management (REVEAL), a longitudinal registry of group I PAH. Methods and Results— Patients who initiated warfarin on study (n=187) were matched 1:1 with patients never on warfarin, by enrollment site, etiology, and diagnosis status. Descriptive analyses were conducted to compare warfarin users and nonusers by etiology. Survival analyses with and without risk adjustment were performed from the time of warfarin initiation or a corresponding quarterly update in matched pairs to avoid immortal time bias. Time-varying covariate models were used as sensitivity analyses. Mean warfarin treatment was 1 year; mean international normalized ratios were 1.9 (IPAH) and 2.0 (SSc-PAH). Two-thirds of patients initiating warfarin discontinued treatment before the last study assessment. There was no survival difference with warfarin in IPAH patients (adjusted hazard ratio, 1.37; P=0.21) or in SSc-PAH patients (adjusted hazard ratio, 1.60; P=0.15) in comparison with matched controls. However, SSc-PAH patients receiving warfarin within the previous year (hazard ratio, 1.57; P=0.031) or any time postbaseline (hazard ratio, 1.49; P=0.046) had increased mortality in comparison with warfarin-naïve patients. Conclusions— No significant survival advantage was observed in IPAH patients who started warfarin. In SSc-PAH patients, long-term warfarin was associated with poorer survival than in patients not receiving warfarin, even after adjusting for confounders. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT00370214. PMID:26510696

Effect of Warfarin Treatment on Survival of Patients With Pulmonary Arterial Hypertension (PAH) in the Registry to Evaluate Early and Long-Term PAH Disease Management (REVEAL).

PubMed

Preston, Ioana R; Roberts, Kari E; Miller, Dave P; Sen, Ginny P; Selej, Mona; Benton, Wade W; Hill, Nicholas S; Farber, Harrison W

2015-12-22

Long-term anticoagulation is recommended in idiopathic pulmonary arterial hypertension (IPAH). In contrast, limited data support anticoagulation in pulmonary arterial hypertension (PAH) associated with systemic sclerosis (SSc-PAH). We assessed the effect of warfarin anticoagulation on survival in IPAH and SSc-PAH patients enrolled in Registry to Evaluate Early and Long-term PAH Disease Management (REVEAL), a longitudinal registry of group I PAH. Patients who initiated warfarin on study (n=187) were matched 1:1 with patients never on warfarin, by enrollment site, etiology, and diagnosis status. Descriptive analyses were conducted to compare warfarin users and nonusers by etiology. Survival analyses with and without risk adjustment were performed from the time of warfarin initiation or a corresponding quarterly update in matched pairs to avoid immortal time bias. Time-varying covariate models were used as sensitivity analyses. Mean warfarin treatment was 1 year; mean international normalized ratios were 1.9 (IPAH) and 2.0 (SSc-PAH). Two-thirds of patients initiating warfarin discontinued treatment before the last study assessment. There was no survival difference with warfarin in IPAH patients (adjusted hazard ratio, 1.37; P=0.21) or in SSc-PAH patients (adjusted hazard ratio, 1.60; P=0.15) in comparison with matched controls. However, SSc-PAH patients receiving warfarin within the previous year (hazard ratio, 1.57; P=0.031) or any time postbaseline (hazard ratio, 1.49; P=0.046) had increased mortality in comparison with warfarin-naïve patients. No significant survival advantage was observed in IPAH patients who started warfarin. In SSc-PAH patients, long-term warfarin was associated with poorer survival than in patients not receiving warfarin, even after adjusting for confounders. URL: http://www.clinicaltrials.gov. Unique identifier: NCT00370214. © 2015 The Authors.

Characteristics of PAHs in farmland soil and rainfall runoff in Tianjin, China.

PubMed

Shi, Rongguang; Xu, Mengmeng; Liu, Aifeng; Tian, Yong; Zhao, Zongshan

2017-10-14

Rainfall runoff can remove certain amounts of pollutants from contaminated farmland soil and result in a decline in water quality. However, the leaching behaviors of polycyclic aromatic hydrocarbons (PAHs) with rainfall have been rarely reported due to wide variations in the soil compositions, rainfall conditions, and sources of soil PAHs in complex farmland ecosystems. In this paper, the levels, spatial distributions, and composition profiles of PAHs in 30 farmland soil samples and 49 rainfall-runoff samples from the Tianjin region in 2012 were studied to investigate their leaching behaviors caused by rainfall runoff. The contents of the Σ 16 PAHs ranged from 58.53 to 3137.90 μg/kg in the soil and 146.58 to 3636.59 μg/L in the runoff. In total, most of the soil sampling sites (23 of 30) were contaminated, and biomass and petroleum combustion were proposed as the main sources of the soil PAHs. Both the spatial distributions of the soil and the runoff PAHs show a decreasing trend moving away from the downtown, which suggested that the leaching behaviors of PAHs in a larger region during rainfall may be mainly affected by the compounds themselves. In addition, 4- and 5-ring PAHs are the dominant components in farmland soil and 3- and 4-ring PAHs dominate the runoff. Comparisons of the PAH pairs and enrichment ratios showed that acenaphthylene, acenaphthene, benzo[a]anthracene, chrysene, and fluoranthene were more easily transferred into water systems from soil than benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[ghi]perylene, and indeno[123-cd]pyrene, which indicated that PAHs with low molecular weight are preferentially dissolved due to their higher solubility compared to those with high molecular weight.

Air-water exchange of PAHs and OPAHs at a superfund mega-site.

PubMed

Tidwell, Lane G; Blair Paulik, L; Anderson, Kim A

2017-12-15

Chemical fate is a concern at environmentally contaminated sites, but characterizing that fate can be difficult. Identifying and quantifying the movement of chemicals at the air-water interface are important steps in characterizing chemical fate. Superfund sites are often suspected sources of air pollution due to legacy sediment and water contamination. A quantitative assessment of polycyclic aromatic hydrocarbons (PAHs) and oxygenated PAH (OPAHs) diffusive flux in a river system that contains a Superfund Mega-site, and passes through residential, urban and agricultural land, has not been reported before. Here, passive sampling devices (PSDs) were used to measure 60 polycyclic aromatic hydrocarbons (PAHs) and 22 oxygenated PAH (OPAHs) in air and water. From these concentrations the magnitude and direction of contaminant flux between these two compartments was calculated. The magnitude of PAH flux was greater at sites near or within the Superfund Mega-site than outside of the Superfund Mega-site. The largest net individual PAH deposition at a single site was naphthalene at a rate of -14,200 (±5780) (ng/m 2 )/day. The estimated one-year total flux of phenanthrene was -7.9×10 5 (ng/m 2 )/year. Human health risk associated with inhalation of vapor phase PAHs and dermal exposure to PAHs in water were assessed by calculating benzo[a]pyrene equivalent concentrations. Excess lifetime cancer risk estimates show potential increased risk associated with exposure to PAHs at sites within and in close proximity to the Superfund Mega-site. Specifically, estimated excess lifetime cancer risk associated with dermal exposure and inhalation of PAHs was above 1 in 1 million within the Superfund Mega-site. The predominant depositional flux profile observed in this study suggests that the river water in this Superfund site is largely a sink for airborne PAHs, rather than a source. Copyright © 2017 Elsevier B.V. All rights reserved.

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

PubMed

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

2014-02-01

We used land-use analysis, PAH concentrations and assemblages, and multivariate statistics to identify sediment PAH sources in a small (~1303 km(2)) urbanizing watershed located in South-Central, Pennsylvania, USA. A geographic information system (GIS) was employed to quantify land-use features that may serve as PAH sources. Urban PAH concentrations were three times higher than rural levels, and were significantly and highly correlated with combined residential/commercial/industrial land use. Principal components analysis (PCA) was used to group sediments with similar PAH assemblages, and correlation analysis compared PAH sediment assemblages to common PAH sources. The strongest correlations were observed between rural sediments (n = 7) and coke-oven emissions sources (r = 0.69-0.78, n = 5), and between urban sediments (n = 22) and coal-tar-based sealcoat dust (r = 0.94, n = 47) suggesting that coal-tar-based sealcoat is an important urban PAH source in this watershed linked to residential and commercial/industrial land use. Copyright © 2013 Elsevier Ltd. All rights reserved.

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

NASA Astrophysics Data System (ADS)

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

2004-06-01

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

Observational Evidence Linking Interstellar UV Absorption to PAH Molecules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blasberger, Avi; Behar, Ehud; Perets, Hagai B.

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

Observational Evidence Linking Interstellar UV Absorption to PAH Molecules

NASA Astrophysics Data System (ADS)

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

2017-02-01

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

BIODEGRADATION OF SEDIMENT-BOUND PAHS IN FIELD-CONTAMINATED SEDIMENT

EPA Science Inventory

The biodegradation of polycyclic aromatic hydrocarbons (PAHs) has been reported to occur under aerobic, sulfate reducing, and denitrifying conditions. PAHs present in contaminated sites, however, are known for their persistence. Most published studies were conducted in systems wh...

The UV to Near-IR Optical Properties of PAHs: A Semi-Empirical Model

NASA Technical Reports Server (NTRS)

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

2005-01-01

Interstellar Polycyclic Aromatic Hydrocarbon (PAH) infrared emission features represent an important and unique diagnostic tool of the chemical and physical conditions throughout the universe. However, one challenge facing the widely accepted PAH emission model has been the detection of infrared features in regions of low UV flux. Utilizing recently published laboratory Near Infrared VIR) PAH ion absorption data measured in our laboratory, we build upon previous models for PAH ion absorption in the UV-Vis to extrapolate a new model which incorporates PAH ion absorption in the NIR. This model provides a basis for comparing the relative energy absorption of PAH ions in the UV-Vis and NIR regions for a wide variety of stellar types. This model demonstrates that the radiation from late-type stars can pump the mid-IR PAH features.

Mechanism-Based Classification of PAH Mixtures to Predict Carcinogenic Potential.

PubMed

Tilton, Susan C; Siddens, Lisbeth K; Krueger, Sharon K; Larkin, Andrew J; Löhr, Christiane V; Williams, David E; Baird, William M; Waters, Katrina M

2015-07-01

We have previously shown that relative potency factors and DNA adduct measurements are inadequate for predicting carcinogenicity of certain polycyclic aromatic hydrocarbons (PAHs) and PAH mixtures, particularly those that function through alternate pathways or exhibit greater promotional activity compared to benzo[a]pyrene (BaP). Therefore, we developed a pathway-based approach for classification of tumor outcome after dermal exposure to PAH/mixtures. FVB/N mice were exposed to dibenzo[def,p]chrysene (DBC), BaP, or environmental PAH mixtures (Mix 1-3) following a 2-stage initiation/promotion skin tumor protocol. Resulting tumor incidence could be categorized by carcinogenic potency as DBC > BaP = Mix2 = Mix3 > Mix1 = Control, based on statistical significance. Gene expression profiles measured in skin of mice collected 12 h post-initiation were compared with tumor outcome for identification of short-term bioactivity profiles. A Bayesian integration model was utilized to identify biological pathways predictive of PAH carcinogenic potential during initiation. Integration of probability matrices from four enriched pathways (P < .05) for DNA damage, apoptosis, response to chemical stimulus, and interferon gamma signaling resulted in the highest classification accuracy with leave-one-out cross validation. This pathway-driven approach was successfully utilized to distinguish early regulatory events during initiation prognostic for tumor outcome and provides proof-of-concept for using short-term initiation studies to classify carcinogenic potential of environmental PAH mixtures. These data further provide a 'source-to-outcome' model that could be used to predict PAH interactions during tumorigenesis and provide an example of how mode-of-action-based risk assessment could be employed for environmental PAH mixtures. © The Author 2015. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

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

PubMed

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

2016-02-01

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

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

NASA Astrophysics Data System (ADS)

Kasumba, John; Holmén, Britt A.

2018-02-01

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

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Hui; Energy Research Institute, University of Leeds, Leeds LS2 9JT; Wu, Chunfei, E-mail: c.wu@leeds.ac.uk

2015-02-15

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

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

PubMed

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

2015-04-21

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

Impact of natural gas extraction on Pah levels in ambient air

PubMed Central

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

2015-01-01

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

Deuterium Enrichment of PAHs by VUV Irradiation of Interstellar Ices

NASA Technical Reports Server (NTRS)

Bernstein, Max P.; Sandford, Scott A.; Allamandola, Louis J.; Gillette, J. Seb; Zare, Richard N.; DeVincenzi, Donald (Technical Monitor)

1998-01-01

Laboratory results demonstrate that polycyclic aromatic hydrocarbons (PAHs) rapidly exchange their hydrogen atoms with those of nearby molecules when they are frozen into low-temperature ices and exposed to vacuum ultraviolet radiation. As a result, PAHs quickly become deuterium-enriched when VUV irradiated in D-containing ices. This mechanism has important consequences for several astrophysical issues owing to the ubiquitous nature of PAHs in the interstellar medium. For example, this process may explain the deuterium enrichments found in PAHs in meteorites and interplanetary dust particles. These results also provide general predictions about the molecular siting of the deuterium on aromatic materials in meteorites if this process produced a significant fraction of their D-enrichment.

Airborne Measurements of atmospheric PAH's across Europe

NASA Astrophysics Data System (ADS)

Davison, B.; Jaward, F.; Jones, K.; Lee, R.

2003-04-01

Atmospheric measurements of PAHs were taken aboard the DRL Falcon 20 during May 2001. A sampling system was designed to work aboard this aircraft platform. Particulate PAHs were collected on a glass fiber filter (GFF) with their gaseous component concentrated on a polyurethane foam sheets located behind the filter. Typically sampling volumes of between 20-50m^3 were collected which equated to a collection time of about 30minutes. In this way the distance travelled was kept within an acceptable level, about 60 nautical miles. The average concentrations of the data set for phenanthrene was 450 pg m-3 while values for many of the heavier PAH marker compounds used in the UK such as benzo(a)pyrene, diben(ah)anthracene were below the detection limits on all flights. The results will be discussed with consideration of location, altitude and airmass trajectory.

BIOAVAILABILITY OF PAHS FROM PYROGENIC AND PETROGENIC SOURCES MEASURED USING GLASS FISH

EPA Science Inventory

Geochemical evidence indicates PAHs associated with pyrogenic sources behave differently than PAHs from petrogenic sources. There is also some evidence and supposition that PAHs from pyrogenic and petrogenic sources demonstrate differing bioavailability. In this study, we evaluat...

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

PubMed

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

2014-12-01

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

Emission and atmospheric transport of particulate PAHs in Northeast Asia.

PubMed

Inomata, Yayoi; Kajino, Mizuo; Sato, Keiichi; Ohara, Toshimasa; Kurokawa, Jun-Ichi; Ueda, Hiromasa; Tang, Ning; Hayakawa, Kazuichi; Ohizumi, Tsuyoshi; Akimoto, Hajime

2012-05-01

The emission, concentration levels, and transboundary transport of particulate polycyclic aromatic hydrocarbons (PAHs) in Northeast Asia were investigated using particulate PAH measurements, the newly developed emission inventory (Regional Emission inventory in ASia for Persistent Organic Pollutants version, REAS-POP), and the chemical transport model (Regional Air Quality Model ver2 for POPs version, RAQM2-POP). The simulated concentrations of the nine particulate PAHs agreed well with the measured concentrations, and the results firmly established the efficacy of REAS/RAQM2-POP. It was found that the PAH concentrations in Beijing (China, source region), which were emitted predominantly from domestic coal, domestic biofuel, and other transformations of coal (including coke production), were approximately 2 orders of magnitude greater than those monitored at Noto (Japan, leeward region). In Noto, the PAH concentrations showed seasonal variations; the PAH concentrations were high from winter to spring due to contributions from domestic coal, domestic biofuel, and other transformations of coal, and low in summer. In summer, these contribution were decrease, instead, other sources, such as the on-road mobile source, were relatively increased compared with those in winter. These seasonal variations were due to seasonal variations in emissions from China, as well as transboundary transport across the Asian continent associated with meteorological conditions. © 2012 American Chemical Society

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

NASA Technical Reports Server (NTRS)

Hudgins, Douglas M.

2005-01-01

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

PAH Metabolites in Bile of European Eel (Anguilla anguilla) from Morocco.

PubMed

Wariaghli, Fatima; Kammann, Ulrike; Hanel, Reinhold; Yahyaoui, Ahmed

2015-12-01

Environmental pollution of fish with organic contaminants is a topic of rising attention in Morocco. Polycyclic aromatic hydrocarbons (PAH) are prominent organic contaminants which are rapidly metabolized in fish. Their metabolites are accumulated in the bile fluid and can be used to assess PAH exposure. The two PAH metabolites 1-hydroxypyrene and 1-hydroxyphenanthrene were quantified in European eels (Anguilla anguilla) from two Moroccan river systems by high-performance liquid chromatography with fluorescence detection. Mean values ranged from 52 to 210 ng/mL 1-hydroxypyrene and from 61 to 73 ng/mL 1-hydroxyphenanthrene. The overall concentrations of PAH metabolites in eel from Morocco appeared moderate compared to eel from European rivers and coastal sites. The present study provides first information on concentrations of PAH metabolites in fish from Morocco.

PAH emissions from old and new types of domestic hot water boilers.

PubMed

Horak, Jiri; Kubonova, Lenka; Krpec, Kamil; Hopan, Frantisek; Kubesa, Petr; Motyka, Oldrich; Laciok, Vendula; Dej, Milan; Ochodek, Tadeas; Placha, Daniela

2017-06-01

Five different domestic heating boilers (automatic, over-fire, with down-draft combustion and gasification) and three types of fuel (lignite, wood and mixed fuel) were examined in 25 combustion tests and correlated with the emissions of particulate matter (PM), carbon monoxide (CO), total organic carbon (TOC) and 12 polycyclic aromatic hydrocarbons (PAHs with MW = 178-278 g/mol) focusing on particle phase. However, the distribution of 12 PAHs in gas phase was considered as well due to the presence mainly of lighter PAHs in gas phase. The PAHs, as well as the CO and TOC, are the indicators of incomplete combustion, and in this study PAH emission increased significantly with increasing emissions of CO and TOC. The PAHs were mainly detected on PM 2.5 , their contents were increasing linearly with increasing PM 2.5 emissions. The highest emission factors of PAHs were measured for boilers of old construction, such as over-fire boiler (5.8-929 mg/kg) and boiler with down-draft combustion (3.1-54.1 mg/kg). Modern types of boilers produced much lower emissions of PAHs, in particular, automatic boiler (0.3-3.3 mg/kg) and gasification boilers (0.2-6.7 mg/kg). In general, the inefficient combustion at reduced output of boilers generated 1.4-17.7 times more emissions of PAHs than the combustion at nominal output of boilers. It is recommended to operate boilers at nominal output with sufficient air supply and to use the proper fuel to minimise PAHs emissions from domestic heating appliances. Copyright © 2017 Elsevier Ltd. All rights reserved.

Spectroscopy of neutral and ionized PAHs. From laboratory studies to astronomical observations

NASA Technical Reports Server (NTRS)

Salama, Farid

2005-01-01

Polycyclic Aromatic Hydrocarbons (PAHs) are an important and ubiquitous component of carbon-bearing materials in space. PAHs are the best-known candidates to account for the IR emission bands (UIR bands) and PAH spectral features are now being used as new probes of the ISM. PAHs are also thought to be among the carriers of the diffuse interstellar absorption bands (DIBs). In the model dealing with the interstellar spectral features, PAHs are present as a mixture of radicals, ions and neutral species. PAH ionization states reflect the ionization balance of the medium while PAH size, composition, and structure reflect the energetic and chemical history of the medium. A major challenge for laboratory astrochemistry is to reproduce (in a realistic way) the physical conditions that are associated with the emission and absorption interstellar zones. An extensive laboratory program has been developed at NASA Ames to assess the physical and chemical properties of PAHs in such environments and to describe how they influence the radiation and energy balance in space and the interstellar chemistry. PAHs, neutrals and ions, are expanded through a pulsed discharge nozzle (PDN) and probed with high-sensitivity cavity ringdown spectroscopy (CRDS). These laboratory experiments provide unique information on the spectra of free, cold large carbon molecules and ions in the gas phase from the ultraviolet and visible range to the near-infrared range. Intrinsic band profiles and band positions of cold gas-phase PAHs can now be measured with high-sensitivity spectroscopy and directly compared to the astronomical data. Preliminary conclusions from the comparison of the laboratory data with astronomical observations of interstellar and circumstellar environments will also be discussed.

Comparative survey of PAHs incidence in Portuguese traditional meat and blood sausages.

PubMed

Roseiro, L C; Gomes, A; Patarata, L; Santos, C

2012-06-01

Sixteen polycyclic aromatic hydrocarbons (PAHs) in representative traditional sausages produced in "Trás-os-Montes" and "Alentejo", were determined. Light PAHs represented similar overall contents in both regions and showed close decreasing order patterns (ACY, PHE, FLR and NAP), irrespective of the product type considered. Amongst the carcinogenic/mutagenic PAHs analyzed (PAH8), both regions also had greater contents associated to BaA and CHR, with slightly higher values for the former compound in "Alentejo" and, oppositely, for the later in "Trás-os-Montes". However, their quantitative comparison showed that the general mean total PAH content found in "Trás-os-Montes" was almost 3-fold higher than in similar products from "Alentejo" and this factor was about 8-fold superior when the PAH8 and PAH4 indicators were compared, expressing benzo[a]pyrene toxic equivalencies (BaPE), 15 times (total mean toxicity), 34 times (PAH8) and 9 times (PAH4) higher. In general terms, the mean BaP content of all analyzed samples from "Alentejo" was 0.41 μg kg(-1). Differently that value in "Trás-os-Montes" reached 3.57 μg kg(-1), expressing concerning average contents of 5.35, 5.87 and 4.51 μg kg(-1) in Chouriço de Carne, Moura and Salpicão sausages, respectively. Copyright © 2012 Elsevier Ltd. All rights reserved.

Remarkably constant PAH concentrations in Swiss soils over the last 30 years.

PubMed

Gubler, Andreas; Wächter, Daniel; Blum, Franziska; Bucheli, Thomas D

2015-10-01

Although polycyclic aromatic hydrocarbons (PAH) are of concern due to their carcinogenic, mutagenic, and teratogenic properties and their ubiquitous occurrence in environmental compartments, only few studies assessed the temporal evolutions of PAH contents of soils over extended time periods. The Swiss Soil Monitoring Network NABO runs long-term monitoring sites resampled every five years since the 1980s. In the present study, soil (0-20 cm) samples collected from 1985 through 2013 at 25 selected monitoring sites were analysed for the 16 priority PAH according to the U.S. EPA and five PAH marker substances. We observed divergent trends for light PAH, such as naphthalene and phenanthrene, compared with heavy PAH, such as benzo[a]pyrene and benzo[ghi]perylene. Whereas the former showed decreasing concentrations since the late 1980s, no significant trends were found for the latter. Furthermore, the analyses showed that naphthalene contents decreased most strongly at rural sites featuring low population densities, while phenanthrene contents generally decreased most strongly at semi-rural sites. The deviating evolutions of light and heavy PAH were mainly attributed to their differing physico-chemical properties. Temporal evolutions in soils contradict emission inventory data suggesting PAH emissions to decline since the 1980s.

Distribution, partition and removal of polycyclic aromatic hydrocarbons (PAHs) during coking wastewater treatment processes.

PubMed

Zhang, Wanhui; Wei, Chaohai; An, Guanfeng

2015-05-01

In this study, we report the performance of a full-scale conventional activated sludge (A-O1-O2) treatment in eliminating polycyclic aromatic hydrocarbons (PAHs). Both aqueous and solid phases along with the coking wastewater treatment processes were analyzed for the presence of 18 PAHs. It was found that the target compounds occurred widely in raw coking wastewater, treated effluent and sludge samples. In the coking wastewater treatment system, 4-5 ring PAHs were the dominant compounds, while 4 rings PAHs predominated in the sludge samples. Over 98% of the PAH removal was achieved in the coking wastewater treatment plant (WWTP), with the total concentration of PAHs being 21.3 ± 1.9 μg L(-1) in the final effluent. During the coking wastewater treatment processes, the association of the lower molecular weight PAH with suspended solids was generally less than 60%, while the association of higher molecular weight PAHs was greater than 90%. High distribution efficiencies (Kdp and Kds) were found, suggesting that adsorption was the potential removal pathway of PAHs. Finally, the mass balances of PAHs in various stages of the coking WWTP were obtained, and the results indicated that adsorption to sludge was the main removal pathway for PAHs in the coking wastewater treatment processes.

Dry Deposition of Polycyclic Aromatic Hydrocarbons (PAHs) at a Suburban Site in Beijing, China

NASA Astrophysics Data System (ADS)

Zhang, Xincheng; Wang, Weiyu; Zhu, Xianlei

2017-04-01

A great amount of polycyclic aromatic hydrocarbons (PAHs) have been generated by industrial production, waste incineration and landfill, traffic and road dust etc. They are emitted into atmosphere and afterwards enter into water body and soil through deposition, resulting in wide distribution of PAHs in environment. However, the dry deposition of PAHs from atmosphere has not been well studied, especially in the aspects of its characteristics, environmental and health effects, sources and mechanism. This study measured PAHs dry deposition in the northwest suburban area of Beijing. Dry deposition samples (i.e. dustfall samples) were collected at the sampling site located in China University of Petroleum - Beijing in 2012-2016. And PAHs in the samples were determined by GC/MS. The dry deposition flux of 16 US EPA priority PAHs (ΣPAH16) was 2.58 μg/(m^2·d), which was lower than those in other regions of North China. Its seasonal variability was more significant than annual variability (p<0.05) and the seasonal pattern was winter > spring > autumn > summer. The amount of ΣPAH16 removed from the atmosphere by dry deposition process accounted for only 1.2% of their emissions, indicating that the atmosphere self-purification capacity was quite limited and emission reduction measures would play a key role in controlling PAHs air pollution. However, PAHs dry deposition would deteriorate soil quality since the content of ΣPAH16 in dustfall was 1-2 orders of magnitude higher than that in soil in the same area. Dermal exposure resulting from PAHs dry deposition was not the major route. The sources of PAHs dry deposition varied with seasons. The profile and specific ratios of PAHs showed that in winter, domestic coal combustion was the main source of PAHs with the contribution up to 77%; in spring and summer, the impact of coal combustion decreased and the contribution of vehicle exhaust increased to 30% - 45%; in fall, in addition to coal combustion and vehicle exhaust

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

NASA Astrophysics Data System (ADS)

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

2011-03-01

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

Source apportionment of elevated wintertime PAHs by compound-specific radiocarbon analysis

NASA Astrophysics Data System (ADS)

Sheesley, R. J.; Kruså, M.; Krecl, P.; Johansson, C.; Gustafsson, Ã.-.

2009-05-01

Natural abundance radiocarbon analysis facilitates distinct source apportionment between contemporary biomass/biofuel (14C "alive") versus fossil fuel (14C "dead") combustion. Here, the first compound-specific radiocarbon analysis (CSRA) of atmospheric polycyclic aromatic hydrocarbons (PAHs) was demonstrated for a set of samples collected in Lycksele, Sweden a small town with frequent episodes of severe atmospheric pollution in the winter. Renewed interest in using residential wood combustion (RWC) means that this type of seasonal pollution is of increasing concern in many areas. Five individual/paired PAH isolates from three pooled fortnight-long filter collections were analyzed by CSRA: phenanthrene, fluoranthene, pyrene, benzo[b+k]fluoranthene and indeno[cd]pyrene plus benzo[ghi]perylene; phenanthrene was the only compound also analyzed in the gas phase. The measured Δ14C for PAHs spanned from -138.3‰ to 58.0‰. A simple isotopic mass balance model was applied to estimate the fraction biomass (fbiomass) contribution, which was constrained to 71-87% for the individual PAHs. Indeno[cd]pyrene plus benzo[ghi]perylene had an fbiomass of 71%, while fluoranthene and phenanthrene (gas phase) had the highest biomass contribution at 87%. The total organic carbon (TOC, defined as carbon remaining after removal of inorganic carbon) fbiomass was estimated to be 77%, which falls within the range for PAHs. This CSRA data of atmospheric PAHs established that RWC is the dominating source of atmospheric PAHs to this region of the boreal zone with some variations among RWC contributions to specific PAHs.

Particle-scale measurement of PAH aqueous equilibrium partitioning in impacted sediments.

PubMed

Ghosh, Upal; Hawthorne, Steven B

2010-02-15

This research investigated the particle-scale processes that control aqueous equilibrium partitioning of PAHs in manufactured gas plant (MGP) site sediments. Dominant particle types in impacted sediments (sand, wood, coal/coke, and pitch) were physically separated under a microscope for equilibrium assessments. Solid-phase microextraction (SPME) combined with selected ion monitoring GC/MS and perdeuterated PAH internal standards were used to determine freely dissolved PAH concentrations in small (0.1-1 mL) water samples at concentrations as low as microg/L (for lower molecular weight PAHs) to ng/L (for higher molecular weight PAHs). For every particle class the initial release of PAHs into the aqueous phase was rapid, and an apparent equilibrium was reached in a matter of days. The average ratio of aqueous total PAH concentration for pitch vs coal/coke particles for eight sediment samples was 20. Thus, sediments that had aged in the field for many decades were not at equilibrium and were still going through a slow process of contaminant mass transfer between the different particle types. A possible consequence of this slow aging process is further lowering of the activity of the chemical as mass transfer is achieved to new sorption sites with time. This study also found that the presence of black carbon even at the level of (1)/(3) of sediment organic carbon does not necessarily imply a BC-dominated sorption behavior, rather source pitch particles if present may dominate PAH partitioning. To our knowledge this is the first report of equilibrium partitioning assessment conducted at the sediment particle scale.

Importance of organic amendment characteristics on bioremediation of PAH-contaminated soil.

PubMed

Lukić, B; Huguenot, D; Panico, A; Fabbricino, M; van Hullebusch, E D; Esposito, G

2016-08-01

This study investigates the importance of the organic matter characteristics of several organic amendments (i.e., buffalo manure, food and kitchen waste, fruit and vegetables waste, and activated sewage sludge) and their influence in the bioremediation of a polycyclic aromatic hydrocarbons (PAH)-contaminated soil. The removal of low molecular weights (LMW) and high molecular weights (HMW) PAHs was monitored in four bioremediation reactors and used as an indicator of the role of organic amendments in contaminant removal. The total initial concentration of LMW PAHs was 234 mg kg(-1) soil (dry weight), while the amount for HMW PAHs was 422 mg kg(-1) soil (dry weight). Monitoring of operational parameters and chemical analysis was performed during 20 weeks. The concentrations of LMW PAH residues in soil were significantly lower in reactors that displayed a mesophilic phase, i.e., 11 and 15 %, compared to reactors that displayed a thermophilic phase, i.e., 29 and 31 %. Residual HMW PAHs were up to five times higher compared to residual LMW PAHs, depending on the reactor. This demonstrated that the amount of added organic matter and macronutrients such as nitrogen and phosphorus, the biochemical organic compound classes (mostly soluble fraction and proteins), and the operational temperature are important factors affecting the overall efficiency of bioremediation. On that basis, this study shows that characterization of biochemical families could contribute to a better understanding of the effects of organic amendments and clarify their different efficiency during a bioremediation process of PAH-contaminated soil.

Host Pah1p phosphatidate phosphatase limits viral replication by regulating phospholipid synthesis

PubMed Central

Zhang, Zhenlu; He, Guijuan; Catanzaro, Nicholas; Wu, Zujian; Xie, Lianhui

2018-01-01

Replication of positive-strand RNA viruses [(+)RNA viruses] takes place in membrane-bound viral replication complexes (VRCs). Formation of VRCs requires virus-mediated manipulation of cellular lipid synthesis. Here, we report significantly enhanced brome mosaic virus (BMV) replication and much improved cell growth in yeast cells lacking PAH1 (pah1Δ), the sole yeast ortholog of human LIPIN genes. PAH1 encodes Pah1p (phosphatidic acid phosphohydrolase), which converts phosphatidate (PA) to diacylglycerol that is subsequently used for the synthesis of the storage lipid triacylglycerol. Inactivation of Pah1p leads to altered lipid composition, including high levels of PA, total phospholipids, ergosterol ester, and free fatty acids, as well as expansion of the nuclear membrane. In pah1Δ cells, BMV replication protein 1a and double-stranded RNA localized to the extended nuclear membrane, there was a significant increase in the number of VRCs formed, and BMV genomic replication increased by 2-fold compared to wild-type cells. In another yeast mutant that lacks both PAH1 and DGK1 (encodes diacylglycerol kinase converting diacylglycerol to PA), which has a normal nuclear membrane but maintains similar lipid compositional changes as in pah1Δ cells, BMV replicated as efficiently as in pah1Δ cells, suggesting that the altered lipid composition was responsible for the enhanced BMV replication. We further showed that increased levels of total phospholipids play an important role because the enhanced BMV replication required active synthesis of phosphatidylcholine, the major membrane phospholipid. Moreover, overexpression of a phosphatidylcholine synthesis gene (CHO2) promoted BMV replication. Conversely, overexpression of PAH1 or plant PAH1 orthologs inhibited BMV replication in yeast or Nicotiana benthamiana plants. Competing with its host for limited resources, BMV inhibited host growth, which was markedly alleviated in pah1Δ cells. Our work suggests that Pah1p promotes

Source apportionment of atmospheric polycyclic aromatic hydrocarbons (PAHs) in Palm Beach County, Florida.

PubMed

Afshar-Mohajer, Nima; Wilson, Christina; Wu, Chang-Yu; Stormer, James E

2016-04-01

Due to concerns about adverse health effects associated with inhalation of atmospheric polycyclic aromatic hydrocarbons (PAHs), 30 ambient air samples were obtained at an air quality monitoring station in Palm Beach County, Florida, from March 2013 to March 2014. The ambient PAH concentration measurements and fractional emission rates of known sources were incorporated into a chemical mass balance model, CMB8.2, developed by EPA, to apportion contributions of three major PAH sources including preharvest sugarcane burning, mobile vehicles, and wildland fires. Strong association between the number of benzene rings and source contribution was found, and mobile vehicles were identified to be the prevailing source (contribution≥56%) for the observed PAHs concentration with lower molecular weights (four or fewer benzene rings) throughout the year. Preharvest sugarcane burning was the primary contributing source for PAHs with relatively higher molecular weights (five or more benzene rings) during the sugarcane burning season (from October to May of the next year). Source contribution of wildland fires varied among PAH compounds but was consistently lower than for sugarcane burning during the sugarcane harvest season. Determining the major sources responsible for ground-level PAHs serves as a tool to improving management strategies for PAH emitting sources and a step toward better protection of the health of residents in terms of exposure to PAHs. The results obtain insight into temporal dominance of PAH polluting sources for those residential areas located near sugarcane burning facilities and have implications beyond Palm Beach County, in areas with high concerns of PAHs and their linked sources. Source apportionment of atmospheric polycyclic hydrocarbons (PAHs) in Palm Beach County, Florida, meant to estimate contributions of major sources in PAH concentrations measured at Belle Glade City of Palm Beach County. Number of benzene rings was found to be the key parameter

Systematic developmental neurotoxicity assessment of a representative PAH Superfund mixture using zebrafish

DOE PAGES

Geier, Mitra C.; James Minick, D.; Truong, Lisa; ...

2018-04-01

Superfund sites often consist of complex mixtures of polycyclic aromatic hydrocarbons (PAHs). It is widely recognized that PAHs pose risks to human and environmental health, but the risks posed by exposure to PAH mixtures are unclear. Here, we constructed an environmentally relevant PAH mixture with the top 10 most prevalent PAHs (SM10) from a Superfund site derived from environmental passive sampling data. Using the zebrafish model, we measured body burden at 48 hours post fertilization (hpf) and evaluated the developmental and neurotoxicity of SM10 and the 10 individual constituents at 24 hours post fertilization (hpf) and 5 days post fertilizationmore » (dpf). Zebrafish embryos were exposed from 6 to 120 hpf to (1) the SM10 mixture, (2) a variety of individual PAHs: pyrene, fluoranthene, retene, benzo[a]anthracene, chrysene, naphthalene, acenaphthene, phenanthrene, fluorene, and 2-methylnaphthalene. We demonstrated that SM10 and only 3 of the individual PAHs were developmentally toxic. Subsequently, we constructed and exposed developing zebrafish to two sub-mixtures: SM3 (comprised of 3 of the developmentally toxicity PAHs) and SM7 (7 non-developmentally toxic PAHs). We found that the SM3 toxicity profile was similar to SM10, and SM7 unexpectedly elicited developmental toxicity unlike that seen with its individual components. The results demonstrated that the overall developmental toxicity in the mixtures could be explained using the general concentration addition model. To determine if exposures activated the AHR pathway, spatial expression of CYP1A was evaluated in the 10 individual PAHs and the 3 mixtures at 5 dpf. Results showed activation of AHR in the liver and vasculature for the mixtures and some individual PAHs. Embryos exposed to SM10 during development and raised in chemical-free water into adulthood exhibited decreased learning and responses to startle stimulus indicating that developmental SM10 exposures affect neurobehavior. Collectively, these

Systematic developmental neurotoxicity assessment of a representative PAH Superfund mixture using zebrafish.

PubMed

Geier, Mitra C; James Minick, D; Truong, Lisa; Tilton, Susan; Pande, Paritosh; Anderson, Kim A; Teeguardan, Justin; Tanguay, Robert L

2018-04-06

Superfund sites often consist of complex mixtures of polycyclic aromatic hydrocarbons (PAHs). It is widely recognized that PAHs pose risks to human and environmental health, but the risks posed by exposure to PAH mixtures are unclear. We constructed an environmentally relevant PAH mixture with the top 10 most prevalent PAHs (SM10) from a Superfund site derived from environmental passive sampling data. Using the zebrafish model, we measured body burden at 48 hours post fertilization (hpf) and evaluated the developmental and neurotoxicity of SM10 and the 10 individual constituents at 24 hours post fertilization (hpf) and 5 days post fertilization (dpf). Zebrafish embryos were exposed from 6 to 120 hpf to (1) the SM10 mixture, (2) a variety of individual PAHs: pyrene, fluoranthene, retene, benzo[a]anthracene, chrysene, naphthalene, acenaphthene, phenanthrene, fluorene, and 2-methylnaphthalene. We demonstrated that SM10 and only 3 of the individual PAHs were developmentally toxic. Subsequently, we constructed and exposed developing zebrafish to two sub-mixtures: SM3 (comprised of 3 of the developmentally toxicity PAHs) and SM7 (7 non-developmentally toxic PAHs). We found that the SM3 toxicity profile was similar to SM10, and SM7 unexpectedly elicited developmental toxicity unlike that seen with its individual components. The results demonstrated that the overall developmental toxicity in the mixtures could be explained using the general concentration addition model. To determine if exposures activated the AHR pathway, spatial expression of CYP1A was evaluated in the 10 individual PAHs and the 3 mixtures at 5 dpf. Results showed activation of AHR in the liver and vasculature for the mixtures and some individual PAHs. Embryos exposed to SM10 during development and raised in chemical-free water into adulthood exhibited decreased learning and responses to startle stimulus indicating that developmental SM10 exposures affect neurobehavior. Collectively, these

Systematic developmental neurotoxicity assessment of a representative PAH Superfund mixture using zebrafish

DOE Office of Scientific and Technical Information (OSTI.GOV)

Geier, Mitra C.; James Minick, D.; Truong, Lisa

Superfund sites often consist of complex mixtures of polycyclic aromatic hydrocarbons (PAHs). It is widely recognized that PAHs pose risks to human and environmental health, but the risks posed by exposure to PAH mixtures are unclear. Here, we constructed an environmentally relevant PAH mixture with the top 10 most prevalent PAHs (SM10) from a Superfund site derived from environmental passive sampling data. Using the zebrafish model, we measured body burden at 48 hours post fertilization (hpf) and evaluated the developmental and neurotoxicity of SM10 and the 10 individual constituents at 24 hours post fertilization (hpf) and 5 days post fertilizationmore » (dpf). Zebrafish embryos were exposed from 6 to 120 hpf to (1) the SM10 mixture, (2) a variety of individual PAHs: pyrene, fluoranthene, retene, benzo[a]anthracene, chrysene, naphthalene, acenaphthene, phenanthrene, fluorene, and 2-methylnaphthalene. We demonstrated that SM10 and only 3 of the individual PAHs were developmentally toxic. Subsequently, we constructed and exposed developing zebrafish to two sub-mixtures: SM3 (comprised of 3 of the developmentally toxicity PAHs) and SM7 (7 non-developmentally toxic PAHs). We found that the SM3 toxicity profile was similar to SM10, and SM7 unexpectedly elicited developmental toxicity unlike that seen with its individual components. The results demonstrated that the overall developmental toxicity in the mixtures could be explained using the general concentration addition model. To determine if exposures activated the AHR pathway, spatial expression of CYP1A was evaluated in the 10 individual PAHs and the 3 mixtures at 5 dpf. Results showed activation of AHR in the liver and vasculature for the mixtures and some individual PAHs. Embryos exposed to SM10 during development and raised in chemical-free water into adulthood exhibited decreased learning and responses to startle stimulus indicating that developmental SM10 exposures affect neurobehavior. Collectively, these

The Infrared Spectra of Polycyclic Aromatic Hydrocarbons with Excess Peripheral H Atoms (Hn-PAHs) and their Relation to the 3.4 and 6.9 µm PAH Emission Features

PubMed Central

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

2015-01-01

Polycyclic aromatic hydrocarbons (PAHs) are likely responsible for the family of infrared emission features seen in a wide variety of astrophysical environments. A potentially important subclass of these materials are PAHs whose edges contain excess H atoms (Hn-PAHs). This type of compound may be present in space, but it has been difficult to assess this possibility because of a lack of suitable laboratory spectra to assist with analysis of astronomical data. We present 4000-500 cm−1 (2.5–20 µm) infrared spectra of 23 Hn-PAHs and related molecules isolated in argon matrices under conditions suitable for interpretation of astronomical data. Spectra of molecules with mixed aromatic and aliphatic domains show characteristics that distinguish them from fully aromatic PAH equivalents. Two major changes occur as PAHs become more hydrogenated: (1) aromatic C-H stretching bands near 3.3 µm weaken and are replaced with stronger aliphatic bands near 3.4 µm, and (2) aromatic C-H out-of-plane bending mode bands in the 11–15 µm region shift and weaken concurrent with growth of a strong aliphatic -CH2-deformation mode near 6.9 µm. Implications for interpreting astronomical spectra are discussed with emphasis on the 3.4 and 6.9 µm features. Laboratory data is compared with emission spectra from IRAS 21282+5050, an object with normal PAH emission features, and IRAS 22272+5435 and IRAS 0496+3429, two protoplanetary nebulae with abnormally large 3.4 µm features. We show that ‘normal’ PAH emission objects contain relatively few Hn-PAHs in their emitter populations, but less evolved protoplanetary nebulae may contain significant abundances of these molecules. PMID:26435553

PAHs sensitivity of picophytoplankton populations in the Red Sea.

PubMed

Kottuparambil, Sreejith; Agusti, Susana

2018-04-25

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

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

PubMed

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

2009-07-15

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

AN OVERVIEW OF PARTITIONING AND BIOAVAILABILITY OF PAHS IN SEDIMENTS AND SOILS

EPA Science Inventory

Understanding and predicting any adverse effects of PAHs depends on generating a reliable measure or estimate of how much PAH is available for uptake. Simply knowing the total amount of PAH in soil, water or sediment is insufficient for determining whether or not these compounds ...

Excited State Trends in Bidirectionally Expanded Closed-Shell PAH and PANH Anions

PubMed Central

Moore, Megan M.; Lee, Timothy J.

2018-01-01

Some anions are known to exhibit excited states independent of external forces such as dipole moments and induced polarizabilities. Such states exist simply as a result of the stabilization of valence accepting orbitals whereby the binding energy of the extra electron is greater than the valence excitation energy. Closed-shell anions are interesting candidates for such transitions since their ground-state, spin-paired nature makes the anions more stable from the beginning. Consequently, this work shows the point beyond which deprotonated, closed-shell polycyclic aromatic hydrocarbons (PAHs) and those PAHs containing nitrogen heteroatoms (PANHs) will exhibit valence excited states. This behavior has already been demonstrated in some PANHs and for anistropically-extended PAHs. This work establishes a general trend for PAHs/PANHs of arbitrary size and directional extension, whether in one dimension or two. Once seven six-membered rings make up a PAH/PANH, valence excited states are present. For most classes of PAHs/PANHs, this number is closer to four. Even though most of these excited states are weak absorbers, the sheer number of PAHs present in various astronomical environments should make them significant contributors to astronomical spectra. PMID:27585793

PAH dissipation in spiked soil: impacts of bioavailability, microbial activity, and trees.

PubMed

Mueller, Kevin E; Shann, Jodi R

2006-08-01

While trees have demonstrated potential in phytoremediation of several organic contaminants, little is known regarding their ability to impact the common soil contaminant PAHs. Several species of native North American trees were planted in soil artificially contaminated with three PAHs. Plant biomass, PAH dissipation, and microbial mineralization were monitored over the course of one year and environmental conditions were allowed to follow typical seasonal patterns. PAH dissipation and mineralization were not affected by planting. Extensive and rapid loss of PAHs was observed and attributed to high bioavailability and microbial activity in all treatments. The rate of this loss may have masked any significant planting effects. Anthracene was found to be more recalcitrant than pyrene or phenanthrene. Parallel soil aging studies indicated that sequestration to soil components was minimal. Contrary to common inferences in literature, amendment with decaying fine roots inhibited PAH degradation by the soil microbial community. Seasonal variation in environmental factors and rhizosphere dynamics may have also reduced or negated the effect of planting and should be taken into account in future phytoremediation trials. The unique root traits of trees may pose a challenge to traditional thought regarding PAH dissipation in the rhizosphere of plants.

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

PubMed

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

2012-12-01

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

Source apportionment of elevated wintertime PAHs by compound-specific radiocarbon analysis

NASA Astrophysics Data System (ADS)

Sheesley, R. J.; Kruså, M.; Krecl, P.; Johansson, C.; Gustafsson, Ã.-.

2008-12-01

Natural abundance radiocarbon analysis facilitates distinct source apportionment between contemporary biomass/biofuel (14C "alive") versus fossil fuel (14C "dead") combustion. Here, the first compound-specific radiocarbon analysis (CSRA) of atmospheric polycylic aromatic hydrocarbons (PAHs) was demonstrated for a set of samples collected in Lycksele, Sweden a small town with frequent episodes of severe atmospheric pollution in the winter. Renewed interest in residential wood combustion means than this type of seasonal pollution is of increasing concern in many areas. Five individual/paired PAH isolates from three pooled fortnight-long filter collections were analyzed by CSRA: phenanthrene, fluoranthene, pyrene, benzo[b+k]fluoranthene and indeno[cd]pyrene plus benzo[ghi]perylene; phenanthrene was the only compound also analyzed in the gas phase. The measured Δ14C for PAHs spanned from -138.3‰ to 58.0‰. A simple isotopic mass balance model was applied to estimate the fraction biomass (fbiomass) contribution that was constrained to a range of 71% for indeno[cd]pyrene+benzo[ghi]perylene to 87% for the gas phase phenanthrene and particulate fluoranthene, respectively. Indeno[cd]pyrene plus benzo[ghi]perylene, known to be enhanced in gasoline-powered motor vehicle exhaust compared to diesel exhaust, had the lowest contribution of biomass combustion of the measured PAHs by 9%. The total organic carbon (TOC, defined as carbon remaining after removal of inorganic carbon) fbiomass was estimated to be 77%, which falls within the range for PAHs. This CSRA data of atmospheric PAHs demonstrate the non-uniformity of biomass combustion contribution to different PAHs even in a location with limited local emission sources and illustrates that regulatory efforts would not evenly reduce all PAHs.

Polycyclic aromatic hydrocarbons and PAH-related DNA adducts.

PubMed

Ewa, Błaszczyk; Danuta, Mielżyńska-Švach

2017-08-01

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

PAHs in leachates from thermal power plant wastes and ash-based construction materials.

PubMed

Irha, Natalya; Reinik, Janek; Jefimova, Jekaterina; Koroljova, Arina; Raado, Lembi-Merike; Hain, Tiina; Uibu, Mai; Kuusik, Rein

2015-08-01

The focus of the current study is to characterise the leaching behaviour of polycyclic aromatic hydrocarbons (PAHs) from oil shale ashes (OSAs) of pulverised firing (PF) and circulating fluidised-bed (CFB) boilers from Estonian Thermal Power Plant (Estonia) as well as from mortars and concrete based on OSAs. The target substances were 16 PAHs from the EPA priority pollutant list. OSA samples and OSA-based mortars were tested for leaching, according to European standard EN 12457-2 (2002). European standard CEN/TC 15862(2012) for monolithic matter was used for OSA-based concrete. Water extracts were analysed by GC-MS for the concentration of PAHs. Naphthalene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene and pyrene were detected. Still, the release of PAHs was below the threshold limit value for inert waste. The amount of the finest fraction (particle size <0.045 mm), the content of the Al-Si glass phase and the surface characteristics were the main factors, which could affect the accessibility of PAHs for leaching. The mobility of PAHs from OSA of CFB and PF boilers was 20.2 and 9.9%, respectively. Hardening of OSA-based materials did not lead to the immobilisation of soluble PAHs. Release of PAHs from the monolith samples did not exceed 0.5 μg/m(2). In terms of leaching of PAHs, OSA is safe to be used for construction purposes.

Anaerobic biodegradation of PAHs in mangrove sediment with amendment of NaHCO3.

PubMed

Li, Chun-Hua; Wong, Yuk-Shan; Wang, Hong-Yuan; Tam, Nora Fung-Yee

2015-04-01

Mangrove sediment is unique in chemical and biological properties. Many of them suffer polycyclic aromatic hydrocarbon (PAH) contamination. However, the study on PAH biological remediation for mangrove sediment is deficient. Enriched PAH-degrading microbial consortium and electron acceptor amendment are considered as two effective measures. Compared to other electron acceptors, the study on CO2, which is used by methanogens, is still seldom. This study investigated the effect of NaHCO3 amendment on the anaerobic biodegradation of four mixed PAHs, namely fluorene (Fl), phenanthrene (Phe), fluoranthene (Flua) and pyrene (Pyr), with or without enriched PAH-degrading microbial consortium in mangrove sediment slurry. The trends of various parameters, including PAH concentrations, microbial population size, electron-transport system activities, electron acceptor and anaerobic gas production were monitored. The results revealed that the inoculation of enriched PAH-degrading consortium had a significant effect with half lives shortened by 7-13 days for 3-ring PAHs and 11-24 days for 4-ring PAHs. While NaHCO3 amendment did not have a significant effect on the biodegradation of PAHs and other parameters, except that CO2 gas in the headspace of experimental flasks was increased. One of the possible reasons is that mangrove sediment contains high concentrations of other electron acceptors which are easier to be utilized by anaerobic bacteria, the other one is that the anaerobes in mangrove sediment can produce enough CO2 gas even without adding NaHCO3. Copyright © 2015. Published by Elsevier B.V.

Sources and potential health risk of gas phase PAHs in Hexi Corridor, Northwest China.

PubMed

Mao, Xiaoxuan; Yu, Zhousuo; Ding, Zhongyuan; Huang, Tao; Ma, Jianmin; Zhang, Gan; Li, Jun; Gao, Hong

2016-02-01

Gas phase polycyclic aromatic hydrocarbons (PAHs) in Hexi Corridor, Northwest China were determined during heating and non-heating seasons, respectively, using passive air samplers. Polyurethane foam (PUF) disks were chosen as the sampling medium. Fifteen PAHs out of the 16 PAHs classified by the United States Environmental Protection Agency (U.S. EPA) were detected in this field sampling investigation. The atmospheric levels of sampled PAHs were higher at urban sites than that at rural sites among 14 sampling sites and increased during heating season. The highest concentration (11.34 ng m(-3)) was observed in Lanzhou during the heating season, the capital and largest industrial city of Gansu Province. PAH contamination in air was dominated by three aromatic ring congeners. Possible sources of PAHs were apportioned using PAH species ratios and the principle component analysis (PCA) combined with a multiple linear regression (MLR) method. Fossil fuel consumption was identified to be the predominant source of PAHs over Hexi Corridor, accounting for 43 % of the concentration of total (15) PAHs. Backward and forward trajectory and cluster analysis were also carried out to identify potential origins of PAHs monitored at several urban and rural sites. Lung cancer risk of local residents to gas phase PAHs via inhalation exposure throughout the province was found to be around a critical value of the lung cancer risk level at 10(-6) recommended by the U.S. EPA risk assessment guideline.

Current State of Knowledge in Microbial Degradation of Polycyclic Aromatic Hydrocarbons (PAHs): A Review

PubMed Central

Ghosal, Debajyoti; Ghosh, Shreya; Dutta, Tapan K.; Ahn, Youngho

2016-01-01

Polycyclic aromatic hydrocarbons (PAHs) include a group of organic priority pollutants of critical environmental and public health concern due to their toxic, genotoxic, mutagenic and/or carcinogenic properties and their ubiquitous occurrence as well as recalcitrance. The increased awareness of their various adverse effects on ecosystem and human health has led to a dramatic increase in research aimed toward removing PAHs from the environment. PAHs may undergo adsorption, volatilization, photolysis, and chemical oxidation, although transformation by microorganisms is the major neutralization process of PAH-contaminated sites in an ecologically accepted manner. Microbial degradation of PAHs depends on various environmental conditions, such as nutrients, number and kind of the microorganisms, nature as well as chemical property of the PAH being degraded. A wide variety of bacterial, fungal and algal species have the potential to degrade/transform PAHs, among which bacteria and fungi mediated degradation has been studied most extensively. In last few decades microbial community analysis, biochemical pathway for PAHs degradation, gene organization, enzyme system, genetic regulation for PAH degradation have been explored in great detail. Although, xenobiotic-degrading microorganisms have incredible potential to restore contaminated environments inexpensively yet effectively, but new advancements are required to make such microbes effective and more powerful in removing those compounds, which were once thought to be recalcitrant. Recent analytical chemistry and genetic engineering tools might help to improve the efficiency of degradation of PAHs by microorganisms, and minimize uncertainties of successful bioremediation. However, appropriate implementation of the potential of naturally occurring microorganisms for field bioremediation could be considerably enhanced by optimizing certain factors such as bioavailability, adsorption and mass transfer of PAHs. The main

Phototransformation rate constants of PAHs associated with soot particles.

PubMed

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

2013-01-15

Photodegradation is a key process governing the residence time and fate of polycyclic aromatic hydrocarbons (PAHs) in particles, both in the atmosphere and after deposition. We have measured photodegradation rate constants of PAHs in bulk deposits of soot particles illuminated with simulated sunlight. The photodegradation rate constants at the surface (k(p)(0)), the effective diffusion coefficients (D(eff)), and the light penetration depths (z(0.5)) for PAHs on soot layers of variable thickness were determined by fitting experimental data with a model of coupled photolysis and diffusion. The overall disappearance rates of irradiated low molecular weight PAHs (with 2-3 rings) on soot particles were influenced by fast photodegradation and fast diffusion kinetics, while those of high molecular weight PAHs (with 4 or more rings) were apparently controlled by either the combination of slow photodegradation and slow diffusion kinetics or by very slow diffusion kinetics alone. The value of z(0.5) is more sensitive to the soot layer thickness than the k(p)(0) value. As the thickness of the soot layer increases, the z(0.5) values increase, but the k(p)(0) values are almost constant. The effective diffusion coefficients calculated from dark experiments are generally higher than those from the model fitting method for illumination experiments. Due to the correlation between k(p)(0) and z(0.5) in thinner layers, D(eff) should be estimated by an independent method for better accuracy. Despite some limitations of the model used in this study, the fitted parameters were useful for describing empirical results of photodegradation of soot-associated PAHs. Copyright © 2012 Elsevier B.V. All rights reserved.

Phototransformation Rate Constants of PAHs Associated with Soot Particles

PubMed Central

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

2013-01-01

Photodegradation is a key process governing the residence time and fate of polycyclic aromatic hydrocarbons (PAHs) in particles, both in the atmosphere and after deposition. We have measured photodegradation rate constants of PAHs in bulk deposits of soot particles illuminated with simulated sunlight. The photodegradation rate constants at the surface (k0p), the effective diffusion coefficients (Deff), and the light penetration depths (z0.5) for PAHs on soot layers of variable thickness were determined by fitting experimental data with a model of coupled photolysis and diffusion. The overall disappearance rates of irradiated low molecular weight PAHs (with 2-3 rings) on soot particles were influenced by fast photodegradation and fast diffusion kinetics, while those of high molecular weight PAHs (with 4 or more rings) were apparently controlled by either the combination of slow photodegradation and slow diffusion kinetics or by very slow diffusion kinetics alone. The value of z0.5 is more sensitive to the soot layer thickness than the k0p value. As the thickness of the soot layer increases, the z0.5 values increase, but the k0p values are almost constant. The effective diffusion coefficients calculated from dark experiments are generally higher than those from the model fitting method for illumination experiments. Due to the correlation between k0p and z0.5 in thinner layers, Deff should be estimated by an independent method for better accuracy. Despite some limitations of the model used in this study, the fitted parameters were useful for describing empirical results of photodegradation of soot-associated PAHs. PMID:23247292

Global time trends in PAH emissions from motor vehicles

PubMed Central

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

2013-01-01

Emission from motor vehicles is the most important source of polycyclic aromatic hydrocarbons (PAHs) in urban areas. Emission factors of individual PAHs for motor vehicles reported in the literature varied 4 to 5 orders of magnitude, leading to high uncertainty in emission inventory. In this study, key factors affecting emission factors of PAHs (EFPAH) for motor vehicles were evaluated quantitatively based on thousands of EFPAH measured in 16 countries for over 50 years. The result was used to develop a global emission inventory of PAHs from motor vehicles. It was found that country and vehicle model year are the most important factors affecting EFPAH, which can be quantified using a monovariate regression model with per capita gross domestic production (purchasing power parity) as a sole independent variable. On average, 29% of variation in log-transformed EFPAH could be explained by the model, which was equivalent to 90% reduction in overall uncertainty on arithmetic scale. The model was used to predict EFPAH and subsequently PAH emissions from motor vehicles for various countries in the world during a period from 1971 to 2030. It was estimated that the global emission reached its peak value of approximate 101 Gg in 1978 and decreased afterwards due to emission control in developed countries. The annual emission picked up again since 1990 owing to accelerated energy consumption in China and other developing countries. With more and more rigid control measures taken in the developing world, global emission of PAHs is currently passing its second peak. It was predicted that the emission would decrease from 77 Gg in 2010 to 42 Gg in 2030. PMID:24198716

[Internal Exposure Levels of PAHs of Primary School Students in Guangzhou].

PubMed

Su, Hui; Zhao, Bo; Zhang, Su-kun; Liu, Shan; Ren, Ming-zhong; Li, Jie; Shi, Xiao-xia

2015-12-01

In order to investigate the internal exposure levels of polycyclic aromatic hydrocarbons (PAHs) in primary school students of Guangzhou, the research collected urine of 78 and 86 primary school students from two primary schools in the summer of 2014, one school located in the ordinary residential area and the other in the industrial area. The contents of 10 kinds of OH-PAHs were tested by the rapid liquid chromatography coupled to triple quadruple tandem mass spectrometry. The results showed that the concentrations of total OH-PAHs in primary school students in the residential zone ranged from 0.83 µmol · mol⁻¹ to 80.63 µmol · mol⁻¹, while those in industrial area ranged from 1.06 µmol · mol⁻¹ to 72.47 µmol · mol⁻¹. The geometric average concentrations were 6.18 µmol · mol⁻¹ and 6.47 µmol · mol⁻¹, respectively, and there was no statistical significance between them (P > 0.05). Comparison of the exposure levels of different components of PAHs in the two areas found that all the OH-PAHs had no significant difference except for the levels of 1- OHP (P < 0.05). We should also pay attention to the higher exposure levels of PAHs in both areas when compared with other researches. In addition, the OH-PAHs in primary school students in the ordinary residential area had a good correlation between 0. 511 and 0.928 (P < 0.01), whereas there was no correlation between 1-OHP and 2-OHN, 1-OHN in the primary school students in the industrial area and other OH-PAHs had relatively weak correlation ranging from 0.338 to 0.855 (P < 0.01). This difference might indicate different pollution sources of PAHs in different functional areas, which was relatively single in the residential area, while the industrial area was polluted by multiple sources of industrial enterprises and logistics transportation emissions.

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

PubMed

Liu, Bian; Jia, Chunrong

2016-01-01

Although exposure to polycyclic aromatic hydrocarbons (PAHs) is common in both environmental and occupational settings, few studies have compared PAH exposure among people with different professions. The purpose of this study was to investigate the variations in recent PAH exposure among different occupational groups over time using national representative samples. The study population consisted of 4162 participants from the 2001 to 2008 National Health and Nutrition Examination Survey, who had both urinary PAH metabolites and occupational information. Four corresponding monohydroxy-PAH urine metabolites: naphthalene (NAP), fluorene (FLUO), phenanthrene (PHEN), and pyrene (PYR) among seven broad occupational groups were analyzed using weighted linear regression models, adjusting for creatinine levels, sociodemographic factors, smoking status, and sampling season. The overall geometric mean concentrations of NAP, FLUO, PHEN, and PYR were 6927, 477, 335, and 87 ng/L, respectively. All four PAH metabolites were elevated in the "extractive, construction, and repair (ECR)" group, with 21-42 % higher concentrations than those in the reference group of "management." Similar trends were seen in the "operators, fabricators, and laborers (OFL)" group for FLUO, PHEN, and PYR. In addition, both "service" and "support" groups had elevated FLUO. Significant (p < 0.001) upward temporal trends were seen in NAP and PYR, with an approximately 6-17 % annual increase, and FLUO and PHEN remained relatively stable. Race and socioeconomic status show independent effects on PAH exposure. Heterogeneous distributions of urinary PAH metabolites among people with different job categories exist at the population level. The upward temporal trends in NAP and PYR warrant reduction in PAH exposure, especially among those with OFL and ECR occupations.

25 years monitoring of PAHs and petroleum hydrocarbons biodegradation in soil.

PubMed

Harmsen, Joop; Rietra, René P J J

2018-05-10

Biodegradation of polycyclic aromatic hydrocarbons (PAHs) and total petroleum hydrocarbons (TPH) in sediment and soil has been monitored on seven experimental fields during periods up to 25 years. With this unique dataset, we investigated long-term very slow biodegradation under field conditions. . The data show that three biodegradation rates can be distinguished for PAHs: 1) rapid degradation during the first year, 2) slow degradation during the following 6 years and 3), subject of this paper, a very slow degradation after 7 years until at least 25 years. Beside 2-, 3- and 4-ring PAHs, also 5- and 6-ring PAHs (aromatic rings) were degraded, all at the same rate during very slow degradation. In the period of very slow degradation, 6% yr -1 of the PAHs present were removed in five fields and 2% yr -1 in two other fields, while in the same period no very slow degradation of TPH could be observed. The remaining petroleum hydrocarbons were high boiling and non-toxic. Using the calculated degradation rates and the independently measured bioavailability of the PAHs (Tenax-method), the PAHs degradation curves of all seven monitored fields could be modelled. Applying the model and data obtained with the Tenax-method for fresh contaminated material, results of long-term biodegradation can be predicted, which can support the use of bioremediation in order to obtain a legally acceptable residual concentration. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Simulation of atmospheric PAH emissions from diesel engines.

PubMed

Durán, A; de Lucas, A; Carmona, M; Ballesteros, R

2001-08-01

Simulation of atmospheric PAH emissions in a typical European passenger car diesel engine at steady conditions or under a certification cycle is made using in-house software. It is based on neural fitting of experimental data from eight different fuels tested under five operating steady conditions (reproducing modes of the European transient urban/extraurban certification cycle). The software allows the determination of PAH emissions as a function of the fuel composition parameters (aromatic content, cetane index, gross heat power, nitrogen and sulphur content) and operation conditions (torque and engine speed). The mathematical model reproduces experimental data with a maximum error of 20%. This tool is very useful, since changes in parameters can be made without experimental cost and the trend in modifications in PAH emissions is immediately obvious.

UV-visible spectroscopy of PAHs and PAHNs in supersonic jet. Astrophysical Implications

NASA Astrophysics Data System (ADS)

Salma, Bejaoui; Salama, Farid

2017-06-01

Polycyclic Aromatic Hydrocarbon (PAHs) molecules are attracting much attention of the astrophysical and astrochemical communities since they are ubiquitous presence in space and could survive in the harsh interstellar medium (ISM). They are proposed as plausible carriers of the still unassigned diffuse interstellar bands (DIBs) for more than two decades now. The so-called PAH - DIB proposal has been based on the abundance of PAHs in the ISM and their stability against the photo and thermo dissociation. Nitrogen is one of the most abundant elements after hydrogen, helium, and carbon [1]. PANHs exhibit spectral features similar to PAHs and may also contribute to unidentified spectral bands.To prove PAHs-DIBs hypothesis, laboratory absorption spectra of aromatic under astrophysical relevant conditions are of crucial importance to compare with the observed DIBs spectra. The most challenging task is to reproduce as closely as technically possible, the physical and chemical conditions that are present in space. Interstellar PAHs are expected to be present as free, cold, neutral molecules and/or charged species [2]. In our laboratory, comparable conditions are achieved using an excellent platform developed in NASA Ames. Our cosmic simulation chamber (COSmIC) allow the measurements of gas phase spectra of neutral and ionized interstellar PAHs analogs by associating a molecular beam with an ionizing discharge to generate a cold plasma expansion (˜ 100 K) [3]. Our approach to assign PAH as carriers of some DIBs is record the electronic spectra of cold PAHs in gas phase and systematic search for a possible correspondence in astronomical DIBs spectra. We report in this work UV-visible absorption spectra of neutral PAHs and PAHNs using the cavity ring down spectroscopy (CRDS) technique. We discuss the effect of the substitution of C-H bond(s) by a nitrogen atom(s) in spectroscopic features of PAHs and their astrophysical application.[1] L. Spitzer, 1978, Physical processes in

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

PAH effects on meio- and microbial benthic communities strongly depend on bioavailability.

PubMed

Lindgren, J Fredrik; Hassellöv, Ida-Maja; Dahllöf, Ingela

2014-01-01

The effects of anthropogenic pollutants in dissimilar habitats can vary depending on differences in bioavailability. The factors determining bioavailability are not yet fully understood. This study was performed to evaluate whether analysis of total PAH concentrations in sediments is a satisfactory measurement to indicate environmental effects or if bioavailability is needed to be taken into account. We have here performed a 60-day experiment, where nominal PAH concentrations of 1,300 μg/kg sediment were added to three different marine sediments. Meiofaunal and microbial communities were analyzed for alterations in community response at 30 and 60 days. Results showed that bioavailability of PAHs varied between the three different sediments. Nonetheless, the petroleum addition gave rise to significant negative effects on all three sediments at both time points. The two direct measurements of toxicity on the microbial community, potential nitrification and denitrification, displayed a lower effect of the PAH addition in the muddy sediment at both time points, compared to the other two sediment types. No effects were seen in the analysis of meiofaunal community structure. Measurements of PAH bioavailability in the three sediment types concurred with the results from the microbial community, revealing a lower bioavailability in the muddy sediment compared to the other two sediment types, 34% compared to sandy and 18% compared to organic at day 0. At day 60 it was 61% lower compared to sandy and 20% lower compared to organic. The negative effects of the PAH addition on the microbial nitrogen cycle were in six out of eight cases best correlated to the amount of alkylated bioavailable PAH in the sediments, and thus microbial nitrogen cycle is a possible good indicator for assessing PAH-induced stress. The results presented here have implications for risk analysis studies of petroleum-contaminated marine sediments; consequently, sediment characteristics and its effects on

The effect of sewage sludge fertilization on the concentration of PAHs in urban soils.

PubMed

Wołejko, Elżbieta; Wydro, Urszula; Jabłońska-Trypuć, Agata; Butarewicz, Andrzej; Łoboda, Tadeusz

2018-01-01

This paper analyses sources of sixteen PAHs - polycyclic aromatic hydrocarbons in urbanized areas by using selected diagnostic ratios. Simultaneously, an attempt was made to determine how sewage sludge changes PAHs content in urbanized areas soils. In the experiment three lawns along the main roads in Bialystok with different traffic intensity, three doses of sewage sludge and two years of study were considered. There was no effect of fertilization with sewage sludge on the sum of 16 PAHs in urban soil samples, nevertheless, the sum of 16 PAHs was reduced from 2.6 in 2011 to 2.3 mg/kg in 2012. Among 16 tested PAHs compounds, benzo[a]pyrene was the most dominant compound in samples collected in both years - about 15% of all PAHs. The results suggest that application of sludge into the soil did not influence the concentration of 2-3-ring, 4-ring and 5-6-ring PAHs. For the objects fertilized with a dose 150.0 Mg/ha, of sludge the total sum of potentially carcinogenic PAHs in the urban soil lowered by approximately 68% in comparison with the control plots. PAHs contamination of the urban soil samples resulted from the influence of coal, petroleum and biomass combustion. Moreover, PAHs can enter soil via at mospheric deposition. Copyright © 2017 Elsevier Ltd. All rights reserved.

Bioremediation of poly-aromatic hydrocarbon (PAH)-contaminated soil by composting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Loick, N.; Hobbs, P.J.; Hale, M.D.C.

2009-07-01

This paper presents a comprehensive and critical review of research on different co-composting approaches to bioremediate hydrocarbon contaminated soil, organisms that have been found to degrade PAHs, and PAH breakdown products. Advantages and limitations of using certain groups of organisms and recommended areas of further research effort are identified. Studies investigating the use of composting techniques to treat contaminated soil are broad ranging and differ in many respects, which makes comparison of the different approaches very difficult. Many studies have investigated the use of specific bio-additives in the form of bacteria or fungi with the aim of accelerating contaminant removal;more » however, few have employed microbial consortia containing organisms from both kingdoms despite knowledge suggesting synergistic relationships exist between them in contaminant removal. Recommendations suggest that further studies should attempt to systemize the investigations of composting approaches to bio-remediate PAH-contaminated soil, to focus on harnessing the biodegradative capacity of both bacteria and fungi to create a cooperative environment for PAH degradation, and to further investigate the array of PAHs that can be lost during the composting process by either leaching or volatilization.« less

Removing PAHs from urban runoff water by combining ozonation and carbon nano-onions.

PubMed

Sakulthaew, Chainarong; Comfort, Steve D; Chokejaroenrat, Chanat; Li, Xu; Harris, Clifford E

2015-12-01

Ozone (O3) is a chemical oxidant capable of transforming polycyclic aromatic hydrocarbons (PAHs) in urban runoff within minutes but complete oxidation to CO2 can take days to weeks. We developed and tested a flow-through system that used ozone to quickly transform PAHs in a runoff stream and then removed the ozone-transformed PAHs via adsorption to carbon nano-onions (CNOs). To quantify the efficacy of this approach, (14)C-labeled phenanthrene and benzo(a)pyrene, as well as a mixture of 16 unlabeled PAHs were used as test compounds. These PAHs were pumped from a reservoir into a flow-through reactor that continuously ozonated the solution. Outflow from the reactor then went to a chamber that contained CNOs to adsorb the ozone-transformed PAHs and allowed clean water to pass. By adding a microbial consortium to the CNOs following adsorption, we observed that bacteria were able to degrade the adsorbed products and release more soluble, biodegradable products back into solution. Control treatments confirmed that parent PAH structures (i.e., non-ozonated) were not biologically degraded following CNO adsorption and that O3-transformed PAHs were not released from the CNOs in the absence of bacteria. These results support the combined use of ozone, carbon nano-onions with subsequent biological degradation as a means of removing PAHs from urban runoff or a commercial waste stream. Copyright © 2015 Elsevier Ltd. All rights reserved.

Endocrine disrupting potential of PAHs and their alkylated analogues associated with oil spills.

PubMed

Lee, Sangwoo; Hong, Seongjin; Liu, Xiaoshan; Kim, Cheolmin; Jung, Dawoon; Yim, Un Hyuk; Shim, Won Joon; Khim, Jong Seong; Giesy, John P; Choi, Kyungho

2017-09-20

Polycyclic aromatic hydrocarbons (PAHs) and alkylated PAHs are known to be major toxic contaminants in spills of petroleum hydrocarbons (oil). Spilled oil undergoes weathering and over time, PAHs go through a series of compositional changes. PAHs can disrupt endocrine functions, and the type of functions affected and associated potencies vary with the type and alkylation status of PAH. In this study, the potential of five major PAHs of crude oil, i.e., naphthalene, fluorene, dibenzothiophene, phenanthrene, and chrysene, and their alkylated analogues (n = 25), to disrupt endocrine functions was evaluated by use of MVLN-luc and H295R cell lines. In the MVLN-luc bioassay, seven estrogen receptor (ER) agonists were detected among 30 tested PAHs. The greatest ER-mediated potency was observed for 1-methylchrysene (101.4%), followed by phenanthrene and its alkylated analogues (range of %-E2max from 1.6% to 47.3%). In the H295R bioassay, significantly greater syntheses of steroid hormones were observed for 20 PAHs. For major PAHs and their alkylated analogues, disruption of steroidogenesis appeared to be more significant than ER-mediated effects. The number and locations of alkyl-moieties alone could not explain differences in the types or the potencies of toxicities. This observation shows that disruption of endocrine functions by some constituents of oil spills could be underestimated if only parent compounds are considered in assessments of hazard and risk.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Yong; Kwok, Sun, E-mail: zhangy96@hku.hk, E-mail: sunkwok@hku.hk

2015-01-01

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

Enhanced arsenic uptake and polycyclic aromatic hydrocarbon (PAH)-dissipation using Pteris vittata L. and a PAH-degrading bacterium.

PubMed

Sun, Lu; Zhu, Ganghui; Liao, Xiaoyong

2018-05-15

This study examined the effects of P. vittata and a polycyclic aromatic hydrocarbon (PAH)-degrading bacterium (Alcaligenes sp.) on arsenic (As) uptake and phenanthrene dissipation. Bacterial inoculation substantially increased As accumulation in plants by 27.8% (frond) and 27.5% (root) at 60d, respectively, compared with the non-inoculated treatment, although temporal change of As translocation and reduction in plants was observed. Bacterial inoculation positively affected plants by improving growth, nutrition and antioxidative activities, and helped to modify soil As availability to the plants, which may benefit in plant tolerance and As accumulation. Plant and bacteria association enhanced phenanthrene dissipation from the soil, with the highest dissipation rate of 96.4% at 60d in the rhizosphere, which might be associated with enhanced bacterial population and activity inspired by the growth of plant. The result reveals that combination of P. vittata and PAH-degrading bacteria can promote As accumulation and phenanthrene dissipation, and can be exploited as a promising strategy for As and PAH co-contamination remediation. Copyright © 2017 Elsevier B.V. All rights reserved.

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

PubMed

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

2018-07-03

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

The IR emission features - Emission from PAH molecules and amorphous carbon particles

NASA Technical Reports Server (NTRS)

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

1987-01-01

Given the current understanding of polycyclic aromatic hydrocarbons (PAHs), the spectroscopic data suggest that are at least two components which contribute to the interstellar emission spectrum: (1) free molecule-sized PAHs producing the narrow features and (2) amorphous carbon particles (which are primarily composed of an irregular 'lattice' of PAHs) contributing to the broad underlying components. An exact treatment of the IR fluorescence from highly vibrationally excited large molecules demonstrates that species containing between 20 and 30 carbon atoms are responsible for the narrow features, although the spectra match more closely with the spectra of amorphous carbon particles. It is concluded that, since little is known about the spectroscopic properties of free PAHs and PAH clusters, much laboratory work is required along with an observational program focusing on the spatial characteristics of the spectra.

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

NASA Astrophysics Data System (ADS)

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

2015-04-01

Coal tar is one of the most hazardous and concerned organic pollutants and the main hazards are polycyclic aromatic hydrocarbons (PAHs). The indigenous microorganisms in soils are capable to degrade PAHs, with essential roles in biochemical process for PAHs natural attenuation. This study investigated 48 soil samples (from 8 depths of 6 boreholes) in Beijing coking and chemistry plant (China) and revealed the correlation between PAHs contamination, soil enzyme activities and microbial community structure, by 16S rRNA denaturing gradient gel electrophoresis (DGGE). At the site, the key contaminants were identified as naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene and anthracene, and the total PAHs concentration ranged from 0.1 to 923.9 mg/kg dry soil. The total PAHs contamination level was positively correlated (p<0.05) with the bacteria count (0.9×107-14.2×107 CFU/mL), catalase activities (0.554-6.230 mL 0.02 M KMnO4/g•h) and dehydrogenase activities (1.9-30.4 TF μg/g•h soil), showing the significant response of microbial population and degrading functions to the organic contamination in soils. The PAHs contamination stimulated the PAHs degrading microbes and promoted their biochemical roles in situ. The positive relationship between bacteria count and dehydrogenase activities (p<0.05) suggested the dominancy of PAHs degrading bacteria in the microbial community. More interestingly, the microbial community deterioration was uncovered via the decline of microbial biodiversity (richness from 16S rRNA DGGE) against total PAHs concentration (p<0.05). Our research described the spatial profiles of PAHs contamination and soil microbial functions at the PAHs heavily contaminated sites, offering deeper understanding on the roles of indigenous microbial community in natural attenuation process.

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

PubMed

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

2015-02-01

The formation of 2-4 ring polycyclic aromatic hydrocarbons (PAH) from the pyrolysis of nine different municipal solid waste fractions (xylan, cellulose, lignin, pectin, starch, polyethylene (PE), polystyrene (PS), polyvinyl chloride (PVC), and polyethylene terephthalate (PET)) were investigated in a fixed bed furnace at 800 °C. The mass distribution of pyrolysis was also reported. The results showed that PS generated the most total PAH, followed by PVC, PET, and lignin. More PAH were detected from the pyrolysis of plastics than the pyrolysis of biomass. In the biomass group, lignin generated more PAH than others. Naphthalene was the most abundant PAH, and the amount of 1-methynaphthalene and 2-methynaphthalene was also notable. Phenanthrene and fluorene were the most abundant 3-ring PAH, while benzo[a]anthracene and chrysene were notable in the tar of PS, PVC, and PET. 2-ring PAH dominated all tar samples, and varied from 40 wt.% to 70 wt.%. For PS, PET and lignin, PAH may be generated directly from the aromatic structure of the feedstock. Copyright © 2014 Elsevier Ltd. All rights reserved.

ASSESSING RISKS FROM PHOTOACTIVATED TOXICITY OF PAHS TO AQUATIC ORGANISMS

EPA Science Inventory

Polycyclic aromatic hydrocarbons (PAHs) are one of the most ubiquitous classes of environmental contaminants. Although most PAHs are toxic only at concentrations large enough to cause narcosis, the toxicity of some can be greatly enhanced through mechanisms that involve molecul...

Energy sources of polycyclic aromatic hydrocarbons. [Carcinogenicity of PAHs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guerin, M. R.

1977-01-01

Combustion is the predominant end-process by which fossil fuels are converted to energy. Combustion, particularly when inefficient, is also the primary technological source of polycyclic aromatic hydrocarbons (PAHs) released into the environment. The need for liquid fuels to supply the transportation industry and for nonpolluting fuels for heat and power generation provide the incentive to commercialize processes to convert coal to substitute natural gas and oil. These processes represent a potentially massive new source of environmental PAHs. Insuring an adequate supply of energy with minimum impact on the environment and on health is one of the most important, urgent, andmore » challenging goals currently facing science and technology. Polycyclic aromatic hydrocarbon related carcinogenesis is among the most important of possible occupational- and environmental-health impacts of much of the current and projected national energy base. An understanding of the relationship of polycyclic aromatic hydrocarbons (PAHs) to human cancer and a continued surveillance of energy sources for PAH content are necessary to minimize this impact.« less

Hydrogenation and dehydrogenation of interstellar PAHs: Spectral characteristics and H2 formation

NASA Astrophysics Data System (ADS)

Andrews, H.; Candian, A.; Tielens, A. G. G. M.

2016-10-01

Context. We have modelled the abundance distribution and IR emission of the first 3 members of the coronene family in the north-west photodissociation region of the well-studied reflection nebulae NGC 7023. Aims: Our aim was 3-fold: I) analyze the distribution of abundances; (II) examine the spectral footprints from the hydrogenation state of polycyclic aromatic hydrocarbons (PAHs); and (III) assess the role of PAHs in the formation of H2 in photodissociation regions. Methods: To model the physical conditions inside the cloud, we used the Meudon PDR Code, and we gave this as input to our kinetic model. We used specific molecular properties for each PAH, based on the latest data available at the present time. We considered the loss of an H atom or an H2 molecule as multiphoton processes, and we worked under the premise that PAHs with extra H atoms can form H2 through an Eley-Rideal abstraction mechanism. Results: In terms of abundances, we can distinguish clear differences with PAH size. The smallest PAH, coronene (C24H12), is found to be easily destroyed down to the complete loss of all of its H atoms. The largest species circumcircumcoronene (C96H24), is found in its normal hydrogenated state. The intermediate size molecule, circumcoronene (C54H18), shows an intermediate behaviour with respect to the other two, where partial dehydrogenation is observed inside the cloud. Regarding spectral variations, we find that the emission spectra in NGC 7023 are dominated by the variation in the ionization of the dominant hydrogenation state of each species at each point inside the cloud. It is difficult to "catch" the effect of dehydrogenation in the emitted PAH spectra since, for any conditions, only PAHs within a narrow size range will be susceptible to dehydrogenation, being quickly stripped off of all H atoms (and may isomerize to cages or fullerenes). The 3 μm region is the most sensitive one towards the hydrogenation level of PAHs. Conclusions: Based on our results, we

Experimental Electronic Spectroscopy of Two PAHs: Naphthalene and 2-METHYL Naphthalene

NASA Astrophysics Data System (ADS)

Friha, H.; Feraud, G.; Pino, T.; Brechignac, Ph.; Parneix, P.; Dhaoudi, Z.; Jaidane, N.; Galila, H.; Troy, T.; Schmidt, T.

2011-06-01

The presence of polycyclic aromatic hydrocarbons (PAHs) in the interstellar medium (ISM) was suggested in the mid-80's. Since then, their important role in the physico-chemical evolution of the ISM has been confirmed. Interstellar PAHs have been in particular proposed as possible carriers of some Diffuse Interstellar Bands (DIBs). These absorption bands are seen in the spectra of reddened stars from the visible to the near infrared and constitute a major astrophysical issue. Our purpose is to obtain electronic spectra of gas phase PAHs which will be used to probe their participation to the interstellar extinction curve from the visible (DIBs) to the UV (bump). For this goal PAHs cations represent an excellent set of target species. A new way of forming PAH+-Ar_n clusters cations has been implemented in the experimental set-up 'ICARE' at ISMO (Orsay) giving us the capability to measure the electronic spectra of cold PAH cations in the gas phase through the "Ar tagging" trick. Two molecules have been investigated in this way: naphthalene (C_1_0H_8) and 2- methyl naphthalene (C_1_1H_1_0). Clusters of naphthalene and (or 2-methyl-naphthalene) with Ar atoms are first formed in a supersonic jet, before being hit by a 281 nm laser beam which photo-ionizes the clusters which are then injected in a molecular beam through a skimmer. A tunable laser beam crossing downstream photo-dissociates the cations. The bare PAH fragments are detected using a Time-Of-Flight spectrometer while scanning the visible laser wavelength from 470 to 690 nm.

Withdrawal of long-term epoprostenol therapy in pulmonary arterial hypertension (PAH).

PubMed

Calcaianu, George; Calcaianu, Mihaela; Canuet, Matthieu; Enache, Irina; Kessler, Romain

2017-01-01

Once initiated for pulmonary arterial hypertension (PAH), epoprostenol treatment usually needs to be delivered for an indefinite duration. It is possible that some participants could be transitioned from epoprostenol to oral therapies. We retrospectively evaluated eight PAH participants transitioned from epoprostenol to PAH oral drugs. The criteria for epoprostenol withdrawal were: (1) persistent improvement of clinic and hemodynamic status; (2) stable dose of epoprostenol for the last three months; and (3) the participant's preference for oral therapy after evaluation of risk-benefit. We evaluated the clinical, functional, and hemodynamic status at baseline, at withdrawal, and after the transition to oral PAH therapy. The transition was completed in all eight participants. Four participants had a complete successful transition (CT) with a stable clinical and hemodynamic course and four participants had a partial successful transition (PT) remaining stable clinically, with a mild hemodynamic worsening, but without need to re-initiate epoprostenol therapy. The four CT participants were treated with epoprostenol for a shorter period of time (CT group: 35 ± 30 versus PT group: 79 ± 49 months, P = 0.08). Mean epoprostenol dosage was lower in the CT group (CT group: 15 ± 1.5 ng/kg/min versus PT group: 24 ± 11 ng/kg/min, P = 0.09). Safe withdrawal of epoprostenol treatment and transition to oral PAH therapy was possible in a small and highly selected group of participants. The majority of these participants had a porto-pulmonary PAH or PAH associated to HIV infection.

PAH air pollution at a Portuguese urban area: carcinogenic risks and sources identification.

PubMed

Slezakova, K; Pires, J C M; Castro, D; Alvim-Ferraz, M C M; Delerue-Matos, C; Morais, S; Pereira, M C

2013-06-01

This study aimed to characterize air pollution and the associated carcinogenic risks of polycyclic aromatic hydrocarbon (PAHs) at an urban site, to identify possible emission sources of PAHs using several statistical methodologies, and to analyze the influence of other air pollutants and meteorological variables on PAH concentrations.The air quality and meteorological data were collected in Oporto, the second largest city of Portugal. Eighteen PAHs (the 16 PAHs considered by United States Environment Protection Agency (USEPA) as priority pollutants, dibenzo[a,l]pyrene, and benzo[j]fluoranthene) were collected daily for 24 h in air (gas phase and in particles) during 40 consecutive days in November and December 2008 by constant low-flow samplers and using polytetrafluoroethylene (PTFE) membrane filters for particulate (PM10 and PM2.5 bound) PAHs and pre-cleaned polyurethane foam plugs for gaseous compounds. The other monitored air pollutants were SO2, PM10, NO2, CO, and O3; the meteorological variables were temperature, relative humidity, wind speed, total precipitation, and solar radiation. Benzo[a]pyrene reached a mean concentration of 2.02 ng m(-3), surpassing the EU annual limit value. The target carcinogenic risks were equal than the health-based guideline level set by USEPA (10(-6)) at the studied site, with the cancer risks of eight PAHs reaching senior levels of 9.98 × 10(-7) in PM10 and 1.06 × 10(-6) in air. The applied statistical methods, correlation matrix, cluster analysis, and principal component analysis, were in agreement in the grouping of the PAHs. The groups were formed according to their chemical structure (number of rings), phase distribution, and emission sources. PAH diagnostic ratios were also calculated to evaluate the main emission sources. Diesel vehicular emissions were the major source of PAHs at the studied site. Besides that source, emissions from residential heating and oil refinery were identified to contribute to PAH levels at

PAHs molecules and heating of the interstellar gas

NASA Technical Reports Server (NTRS)

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

1989-01-01

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

Priority PAHs in orthodox black tea during manufacturing process.

PubMed

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

2013-08-01

Orthodox black tea is obtained from fresh leaves followed by withering, rolling, fermentation and drying. The presence of 16 priority polycyclic aromatic hydrocarbons (PAHs) was studied in fresh leaves and at various stages of manufacturing. Benzo(a)pyrene (2A: probable human carcinogen) was found in dried tea leaves only whereas, naphthalene (2B: probable human carcinogen) was present during all the stages of manufacturing. Dry tea leaves showed higher content of total 16 PAHs (∑PAHs) about 3 and 211 times than present in withered and dried leaves, respectively. Chrysene, benzo[g,h,i]perylene, indendo[1,2,3-c,d]pyrene, dibenzo[a,h]pyrene and benzo[a]antracene were not found during manufacturing stages of tea.

PHOTOINDUCED TOXICITY OF PAHS AND ALKYLATED PAHS TO A MARINE INFAUNAL AMPHIPOD (RHEPOXYNIUS ABRONIUS)

EPA Science Inventory

The marine infaunal amphipod Rhepoxynius abronius was exposed in standard 10-day toxicity tests to sediments contaminated with parent or alkylated PAHs. After exposures, mortalities (LC50 values) and the ability to rebury in control sediment (EC50 values) were determined. Survivo...

Excretion of polycyclic aromatic hydrocarbon metabolites (OH-PAHs) in cattle urine in Ghana.

PubMed

Bortey-Sam, Nesta; Ikenaka, Yoshinori; Akoto, Osei; Nakayama, Shouta M M; Marfo, Jemima; Saengtienchai, Aksorn; Mizukawa, Hazuki; Ishizuka, Mayumi

2016-11-01

Previous studies of polycyclic aromatic hydrocarbons (PAHs) in particulate matter, soils and livers of wild rats indicated that the city centre of Kumasi, Ghana has been severely polluted with high cancer potency. Cattle urine were therefore collected from Kumasi (urban) and Offinso (rural), Ghana: to determine concentrations of urinary PAH metabolites (OH-PAHs); and find their association with sex; and to estimate exposure of cattle to PAHs from the different sites. From the results, geometric mean concentrations (adjusted by specific gravity), GM SG , showed that 2-OHNaphthalene (2-OHNap) was the most abundant OH-PAH in cattle urine from all study sites, and naphthalene-containing-mothballs might have contributed significantly to the levels. There was no significant difference between urinary OH-PAHs concentrations in cattle from urban and rural sites except for 2-OHPhe and 4-OHPhe, and similar to urban areas, rural sites could also be polluted with PAHs. GM SG of 2-OHNap in cattle urine in Kokote (21.9 ± 6.51 ng/mL; a rural area), was significantly higher compared to the other sites followed by Oforikrom (4.15 ± 4.37 ng/mL; urban). The GM SG concentration (ng/mL) of the sum of OH-PAHs decreased in the order, Kokote (44.7) > Oforikrom (7.87) > Saboa (6.98) > Santasi (6.68) > and Twumasen Estate (5.23). The high concentrations of urinary 2-OHNap, 2-3-OHFlu, 2-OHPhe, 3-OHPhe and 4-OHPhe in Kokote indicated high PAHs exposure to cattle in this area or different/specific source of PAHs exposure. GM SG of 2-OHNap was significantly higher in male cattle compared to females while 1-9-OHPhe was significantly higher in females. Copyright © 2016. Published by Elsevier Ltd.

A statistical approach to develop a detailed soot growth model using PAH characteristics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raj, Abhijeet; Celnik, Matthew; Shirley, Raphael

A detailed PAH growth model is developed, which is solved using a kinetic Monte Carlo algorithm. The model describes the structure and growth of planar PAH molecules, and is referred to as the kinetic Monte Carlo-aromatic site (KMC-ARS) model. A detailed PAH growth mechanism based on reactions at radical sites available in the literature, and additional reactions obtained from quantum chemistry calculations are used to model the PAH growth processes. New rates for the reactions involved in the cyclodehydrogenation process for the formation of 6-member rings on PAHs are calculated in this work based on density functional theory simulations. Themore » KMC-ARS model is validated by comparing experimentally observed ensembles on PAHs with the computed ensembles for a C{sub 2}H{sub 2} and a C{sub 6}H{sub 6} flame at different heights above the burner. The motivation for this model is the development of a detailed soot particle population balance model which describes the evolution of an ensemble of soot particles based on their PAH structure. However, at present incorporating such a detailed model into a population balance is computationally unfeasible. Therefore, a simpler model referred to as the site-counting model has been developed, which replaces the structural information of the PAH molecules by their functional groups augmented with statistical closure expressions. This closure is obtained from the KMC-ARS model, which is used to develop correlations and statistics in different flame environments which describe such PAH structural information. These correlations and statistics are implemented in the site-counting model, and results from the site-counting model and the KMC-ARS model are in good agreement. Additionally the effect of steric hindrance in large PAH structures is investigated and correlations for sites unavailable for reaction are presented. (author)« less

Are Urinary PAHs Biomarkers of Controlled Exposure to Diesel Exhaust?

EPA Science Inventory

Urinary polycyclic aromatic hydrocarbons (PAHs) were evaluated as possible biomarkers of exposure to diesel exhaust (DE) in two controlled-chamber studies. We report levels of 14 PAHs from 28 subjects in urine that were collected before, immediately after and the morning after ex...

Microbial communities to mitigate contamination of PAHs in soil--possibilities and challenges: a review.

PubMed

Fernández-Luqueño, F; Valenzuela-Encinas, C; Marsch, R; Martínez-Suárez, C; Vázquez-Núñez, E; Dendooven, L

2011-01-01

Although highly diverse and specialized prokaryotic and eukaryotic microbial communities in soil degrade polycyclic aromatic hydrocarbons (PAHs), most of these are removed slowly. This review will discuss the biotechnological possibilities to increase the microbial dissipation of PAHs from soil as well as the main biological and biotechnological challenges. Microorganism provides effective and economically feasible solutions for soil cleanup and restoration. However, when the PAHs contamination is greater than the microbial ability to dissipate them, then applying genetically modified microorganisms might help to remove the contaminant. Nevertheless, it is necessary to have a more holistic review of the different individual reactions that are simultaneously taking place in a microbial cell and of the interactions microorganism-microorganism, microorganism-plant, microorganism-soil, and microorganisms-PAHs. Elucidating the function of genes from the PAHs-polluted soil and the study in pure cultures of isolated PAHs-degrading organisms as well as the generation of microorganisms in the laboratory that will accelerate the dissipation of PAHs and their safe application in situ have not been studied extensively. There is a latent environmental risk when genetically engineered microorganisms are used to remedy PAHs-contaminated soil.

Source characterization and exposure modeling of gas-phase polycyclic aromatic hydrocarbon (PAH) concentrations in Southern California

NASA Astrophysics Data System (ADS)

Masri, Shahir; Li, Lianfa; Dang, Andy; Chung, Judith H.; Chen, Jiu-Chiuan; Fan, Zhi-Hua (Tina); Wu, Jun

2018-03-01

Airborne exposures to polycyclic aromatic hydrocarbons (PAHs) are associated with adverse health outcomes. Because personal air measurements of PAHs are labor intensive and costly, spatial PAH exposure models are useful for epidemiological studies. However, few studies provide adequate spatial coverage to reflect intra-urban variability of ambient PAHs. In this study, we collected 39-40 weekly gas-phase PAH samples in southern California twice in summer and twice in winter, 2009, in order to characterize PAH source contributions and develop spatial models that can estimate gas-phase PAH concentrations at a high resolution. A spatial mixed regression model was constructed, including such variables as roadway, traffic, land-use, vegetation index, commercial cooking facilities, meteorology, and population density. Cross validation of the model resulted in an R2 of 0.66 for summer and 0.77 for winter. Results showed higher total PAH concentrations in winter. Pyrogenic sources, such as fossil fuels and diesel exhaust, were the most dominant contributors to total PAHs. PAH sources varied by season, with a higher fossil fuel and wood burning contribution in winter. Spatial autocorrelation accounted for a substantial amount of the variance in total PAH concentrations for both winter (56%) and summer (19%). In summer, other key variables explaining the variance included meteorological factors (9%), population density (15%), and roadway length (21%). In winter, the variance was also explained by traffic density (16%). In this study, source characterization confirmed the dominance of traffic and other fossil fuel sources to total measured gas-phase PAH concentrations while a spatial exposure model identified key predictors of PAH concentrations. Gas-phase PAH source characterization and exposure estimation is of high utility to epidemiologist and policy makers interested in understanding the health impacts of gas-phase PAHs and strategies to reduce emissions.

Photochemistry of Polycyclic Aromatic Hydrocarbons in Cosmic Water Ice: The Role of PAH Ionization and Concentration

NASA Astrophysics Data System (ADS)

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

2015-01-01

Infrared spectroscopic studies of ultraviolet (UV) irradiated, water-rich, cosmic ice analogs containing small polycyclic aromatic hydrocarbons (PAHs) are described. The irradiation studies of anthracene:H2O, pyrene:H2O, and benzo[ghi]perylene:H2O ices (14 K) at various concentrations reported by Bouwman et al. are extended. While aromatic alcohols and ketones have been reported in residues after irradiated PAH:H2O ices were warmed to 270 K, it was not known if they formed during ice irradiation or during warm-up when reactants interact as H2O sublimes. Recent work has shown that they form in low temperature ice. Using DFT computed IR spectra to identify photoproducts and PAH cations, we tentatively identify the production of specific alcohols [PAH(OH) n ] and quinones [PAH(O) n ] for all PAH:H2O ices considered here. Little evidence is found for hydrogenation at 14 K, consistent with the findings of Gudipati & Yang. Addition of O and OH to the parent PAH is the dominant photochemical reaction, but PAH erosion to smaller PAHs (producing CO2 and H2CO) is also important. DFT spectra are used to assess the contribution of PAH-related species to interstellar absorption features from 5 to 9 μm. The case is made that PAH cations are important contributors to the C2 component and PAH(OH) n and PAH(O) n to the C5 component described by Boogert et al. Thus, interstellar ices should contain neutral and ionized PAHs, alcohols, ketones and quinones at the ~2%-4% level relative to H2O. PAHs, their photoproducts, and ion-mediated processes should therefore be considered when modeling interstellar ice processes.

Source Characterization and Exposure Modeling of Gas-Phase Polycyclic Aromatic Hydrocarbon (PAH) Concentrations in Southern California.

PubMed

Masri, Shahir; Li, Lianfa; Dang, Andy; Chung, Judith H; Chen, Jiu-Chiuan; Fan, Zhi-Hua Tina; Wu, Jun

2018-03-01

Airborne exposures to polycyclic aromatic hydrocarbons (PAHs) are associated with adverse health outcomes. Because personal air measurements of PAHs are labor intensive and costly, spatial PAH exposure models are useful for epidemiological studies. However, few studies provide adequate spatial coverage to reflect intra-urban variability of ambient PAHs. In this study, we collected 39-40 weekly gas-phase PAH samples in southern California twice in summer and twice in winter, 2009, in order to characterize PAH source contributions and develop spatial models that can estimate gas-phase PAH concentrations at a high resolution. A spatial mixed regression model was constructed, including such variables as roadway, traffic, land-use, vegetation index, commercial cooking facilities, meteorology, and population density. Cross validation of the model resulted in an R 2 of 0.66 for summer and 0.77 for winter. Results showed higher total PAH concentrations in winter. Pyrogenic sources, such as fossil fuels and diesel exhaust, were the most dominant contributors to total PAHs. PAH sources varied by season, with a higher fossil fuel and wood burning contribution in winter. Spatial autocorrelation accounted for a substantial amount of the variance in total PAH concentrations for both winter (56%) and summer (19%). In summer, other key variables explaining the variance included meteorological factors (9%), population density (15%), and roadway length (21%). In winter, the variance was also explained by traffic density (16%). In this study, source characterization confirmed the dominance of traffic and other fossil fuel sources to total measured gas-phase PAH concentrations while a spatial exposure model identified key predictors of PAH concentrations. Gas-phase PAH source characterization and exposure estimation is of high utility to epidemiologist and policy makers interested in understanding the health impacts of gas-phase PAHs and strategies to reduce emissions.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cook, Amanda M.; Mattioda, Andrew L.; Roser, Joseph

2015-01-20

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

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

NASA Astrophysics Data System (ADS)

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

2014-08-01

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

Formation of nitro-PAHs from the heterogeneous reaction of ambient particle-bound PAHs with N2O5/NO3/NO2

PubMed Central

Zimmermann, Kathryn; Jariyasopit, Narumol; Massey Simonich, Staci L.; Tao, Shu; Atkinson, Roger; Arey, Janet

2014-01-01

Reactions of ambient particles collected from four sites within the Los Angeles, CA air basin and Beijing, China with a mixture of N2O5, NO2, and NO3 radicals were studied in an environmental chamber at ambient pressure and temperature. Exposures in the chamber system resulted in the degradation of particle-bound PAHs and formation of molecular weight (mw) 247 nitropyrenes (NPYs) and nitrofluoranthenes (NFLs), mw 273 nitrotriphenylenes (NTPs), nitrobenz[a]anthracenes (NBaAs), and nitrochrysene (NCHR), and mw 297 nitrobenzo[a]pyrene (NBaP). The distinct isomer distributions resulting from exposure of filter-adsorbed deuterated fluoranthene to N2O5/NO3/NO2 and that collected from the chamber gas-phase suggest that formation of NFLs in ambient particles did not occur by NO3 radical-initiated reaction, but from reaction of N2O5, presumably subsequent to its surface adsorption. Accordingly, isomers known to result from gas-phase radical-initiated reactions of parent PAHs, such as 2-NFL and 2- and 4-NPY, were not enhanced from the exposure of ambient particulate matter to N2O5/NO3/NO2. The reactivity of ambient particles toward nitration by N2O5/NO3/NO2, defined by relative 1-NPY formation, varied significantly, with the relative amounts of freshly emitted particles versus aged particles (particles that had undergone atmospheric chemical processing) affecting the reactivity of particle-bound PAHs toward heterogeneous nitration. Analyses of unexposed ambient samples suggested that, in nighttime samples where NO3 radical-initiated chemistry had occurred, heterogeneous formation of 1-NPY on ambient particles may have contributed to the ambient 1-NPY concentrations at downwind receptor sites. These results, together with observations that 2-NFL is consistently the dominant particle-bound nitro-PAH measured in ambient atmospheres, suggest that for PAHs that exist in both the gas- and particle-phase, the heterogeneous formation of particle-bound nitro-PAHs is a minor formation

The anharmonic quartic force field infrared spectra of hydrogenated and methylated PAHs.

PubMed

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

2018-01-03

Polycyclic aromatic hydrocarbons (PAHs) have been shown to be ubiquitous in a large variety of distinct astrophysical environments and are therefore of great interest to astronomers. The majority of these findings are based on theoretically predicted spectra, which make use of scaled DFT harmonic frequencies for band positions and the double harmonic approximation for intensities. However, these approximations have been shown to fail at predicting high-resolution gas-phase infrared spectra accurately, especially in the CH-stretching region (2950-3150 cm -1 , 3 μm). This is particularly worrying for the subset of hydrogenated or methylated PAHs to which astronomers attribute the observed non-aromatic features that appear in the CH-stretching region of spectral observations of the interstellar medium (ISM). In our previous work, we presented the anharmonic theoretical spectra of three linear PAHs and five non-linear PAHs, demonstrating the importance of including anharmonicities into theoretical calculations. In this work we extend these techniques to two methylated PAHs (9-methylanthracene, and 9,10-dimethylanthracene) and four hydrogenated PAHs (9,10-dihydroanthracene, 9,10-dihydrophenanthrene, 1,2,3,4-tetrahydronaphthalene, and 1,2,3,6,7,8-hexahydropyrene) in order to better understand the aliphatic IR features of substituted PAHs. The theoretical spectra are compared with the spectra obtained under matrix isolation low-temperature conditions for the full vibrational fundamental range and under high-resolution, low-temperature gas-phase conditions for the CH-stretching region. Excellent agreement is observed between the theoretical and high-resolution experimental spectra with a deviation of 0.00% ± 0.17%, and changes to the spectra of PAHs upon methylation and hydrogenated are tracked accurately and explained.

Contribution of PAHs from coal-tar pavement sealcoat and other sources to 40 U.S. lakes

USGS Publications Warehouse

Van Metre, Peter C.; Mahler, Barbara J.

2010-01-01

Contamination of urban lakes and streams by polycyclic aromatic hydrocarbons (PAHs) has increased in the United States during the past 40 years. We evaluated sources of PAHs in post-1990 sediments in cores from 40 lakes in urban areas across the United States using a contaminant mass-balance receptor model and including as a potential source coal-tar-based (CT) sealcoat, a recently recognized source of urban PAH. Other PAH sources considered included several coal- and vehicle-related sources, wood combustion, and fuel-oil combustion. The four best modeling scenarios all indicate CT sealcoat is the largest PAH source when averaged across all 40 lakes, contributing about one-half of PAH in sediment, followed by vehicle-related sources and coal combustion. PAH concentrations in the lakes were highly correlated with PAH loading from CT sealcoat (Spearman's rho=0.98), and the mean proportional PAH profile for the 40 lakes was highly correlated with the PAH profile for dust from CT-sealed pavement (r=0.95). PAH concentrations and mass and fractional loading from CT sealcoat were significantly greater in the central and eastern United States than in the western United States, reflecting regional differences in use of different sealcoat product types. The model was used to calculate temporal trends in PAH source contributions during the last 40 to 100 years to eight of the 40 lakes. In seven of the lakes, CT sealcoat has been the largest source of PAHs since the 1960s, and in six of those lakes PAH trends are upward. Traffic is the largest source to the eighth lake, located in southern California where use of CT sealcoat is rare.

Determination of oxygen, nitrogen, and sulfur-containing polycyclic aromatic hydrocarbons (PAHs) in urban stream sediments.

PubMed

Witter, Amy E; Nguyen, Minh H

2016-02-01

Recent studies indicate that PAH transformation products such as ketone or quinone-substituted PAHs (OPAHs) are potent aryl hydrocarbon receptor (AhR) activators that elicit toxicological effects independent of those observed for PAHs. Here, we measured eight OPAHs, two sulfur-containing (SPAH), one oxygen-containing (DBF), and one nitrogen-containing (CARB) heterocyclic PAHs (i.e. ΣONS-PAHs = OPAH8 + SPAH + DBF + CARB) in 35 stream sediments collected from a small (∼1303 km(2)) urban watershed located in south-central Pennsylvania, USA. Combined ΣONS-PAH concentrations ranged from 59 to 1897 μg kg(-1) (mean = 568 μg kg(-1); median = 425 μg kg(-1)) and were 2.4 times higher in urban versus rural areas, suggesting that activities taking place on urban land serve as a source of ΣONS-PAHs to sediments. To evaluate urban land use metrics that might explain these data, Spearman rank correlation analyses was used to evaluate the degree of association between ΣONS-PAH concentrations and urban land-use/land-cover metrics along an urban-rural transect at two spatial scales (500-m and 1000-m upstream). Combined ΣONS-PAH concentrations showed highly significant (p < 0.0001) correlations with ΣPAH19, residential and commercial/industrial land use (RESCI), and combined state and local road miles (MILES), suggesting that ΣONS-PAHs originate from similar sources as PAHs. To evaluate OPAH sources, a subset of ΣONS-PAHs for which reference assemblages exist, an average OPAH fractional assemblage for urban sediments was derived using agglomerative hierarchal cluster (AHC) analysis, and compared to published OPAH source profiles. Urban sediments from the Condoguinet Creek (n = 21) showed highly significant correlations with urban particulate matter (X(2) = 0.05, r = 0.91, p = 0.0047), suggesting that urban particulate matter is an important OPAH source to sediments in this watershed. Results suggest the inclusion of ΣONS-PAH measurements

Radiation Processing of Polycyclic Aromatic Hydrocarbons (PAHs) in Space: ICEE PoC

NASA Technical Reports Server (NTRS)

Mattioda, Andrew; Cruz-Diaz, Gustavo; Barnhardt, Michael; Ging, Andrew; Schneider, Todd; Vaughn, Jason; Quigley, Emmett; Phillips, Brandon

2017-01-01

Small Polycyclic Aromatic Hydrocarbon molecules or PAHs (<30 carbon atoms) have been identified in comets, meteorites, asteroids, and interplanetary dust particles in our Solar System, while PAHs in the Interstellar Medium (ISM) tend to be much larger, usually between 50 to 100 carbon atoms in size. The cause of the size disparity between PAHs found in the ISM and Solar System as well as their influence on Solar System organics is not yet understood. Two chemical evolutionary paths have been proposed to explain the inventory of solar system organics. In one the prebiotic material was formed from the radiation induced modification of large pre-solar carbon-bearing species (e.g. ISM PAHs). The second path suggests that Solar System prebiotic matter is the result of bottom-up synthesis from small reactive molecules after the Solar System was formed. In this second scenario very few ISM PAHs survived the harsh pre-solar radiation as aromatic structures. ICEE PoC (ICEE Proof of Concept) investigated factors impacting the chemical evolution of large PAHs irradiated under conditions similar to the proto-solar nebula. Likewise ICEE PoC will refine the technical parameters of the proposed ICEE (Institute for Carbon Evolution Experiment) laboratory.

PAHs in corn grains submitted to drying with firewood.

PubMed

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

2017-01-15

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

Polycyclic aromatic hydrocarbon (PAH)-phase associations in Washington coastal sediment

NASA Astrophysics Data System (ADS)

Prahl, Fredrick G.; Carpenter, Roy

1983-06-01

Polycyclic aromatic (PAH) and aliphatic hydrocarbon compositions, organic carbon, nitrogen and lignin contents were determined in whole, unfractionated sediment from the Washington continental shelf and in discrete sediment fractions separated by particle size and density. At least 20 to 25% of perylene and PAH derived from pyrolytic processes and 50% of the retene measured in whole sediment are contained within organic C- and lignin-rich panicles of density ≤ 1.9 g/cc. These particles, which include primarily vascular plant remains and bits of charcoal, comprise less than 1% of the total sediment weight. In contrast, a series of methylated phenanthrene homologs, possibly of fossil origin, are concentrated in some component of the more dense, lithic matrix of the sediment. Equilibrium models of PAH sorption/desorption from aqueous phase onto small particles of high surface area do not appear applicable to the behavior of the major PAH types identified in this aquatic environment.

Concentration, sources and risk assessment of PAHs in bottom sediments.

PubMed

Baran, Agnieszka; Tarnawski, Marek; Urbański, Krzysztof; Klimkowicz-Pawlas, Agnieszka; Spałek, Iwona

2017-10-01

The aims of the study were to investigate the concentration, sources and ecological risk of PAHs (polycyclic aromatic hydrocarbons) in bottom sediments collected from nine reservoirs located in south-eastern Poland. The concentration of ∑PAHs in sediments ranged from 150 to 33,900 μg kg -1 . The total PAH concentration in the bottom sediments was arranged in the following order: Rybnik > Rzeszów > Brzóza Królewska > Brzóza Stadnicka > Besko > Chechło > Ożanna > Głuchów > Narożniki. BAP was the major compound in sediments from the Besko, Brzóza Stadnicka and Rzeszów reservoirs; FLT in the sediments from the Rybnik, Narożniki, Ożanna and Brzóza Królewska reservoirs; and FLN from the Głuchów and Chechło reservoirs. The major inputs of PAHs were of pyrolytic origin. However, petrogenic sources of PAHs occurred especially in the Chechło and Głuchów reservoirs. The ecological risk assessment indicated that non-adverse effects on the benthic fauna may occur for sediments from the Głuchów, Narozniki and Ożanna reservoirs, while slightly adverse effects were found for sediments from the Brzóza Królewska, Besko, Brzóza Stadnicka and Chechło reservoirs. The other sediments showed moderate (Rzeszów reservoirs) and strong effect (Rybnik reservoir) on biological communities. Individual PAHs such as NAP, PHE, FLT, PYR, BAA, CHR and BAP in sediments from the Rybnik reservoir and BAP in sediments from the Rzeszów reservoirs indicated a higher possibility of occurrence of an adverse ecological effect. PCA analysis found slight difference between the reservoirs in the profile of variable PAHs. Only the sediments from the Rybnik and Chechło reservoirs differ considerably from this grouping.

Environmental polycyclic aromatic hydrocarbon (PAH) exposure and DNA damage in Mexican children.

PubMed

Sánchez-Guerra, Marco; Pelallo-Martínez, Nadia; Díaz-Barriga, Fernando; Rothenberg, Stephen J; Hernández-Cadena, Leticia; Faugeron, Sylvain; Oropeza-Hernández, Luis F; Guaderrama-Díaz, Margarita; Quintanilla-Vega, Betzabet

2012-02-18

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants presenting a public health risk, particularly to children, a vulnerable population. PAHs have genotoxic and carcinogenic properties, which depend on their metabolism. Many enzymes involved in PAH metabolism, including CYP1A1, CYP1B1, GSTM and GSTT are polymorphic, which may modulate the activation/deactivation of these compounds. We evaluated PAH exposure and DNA damage in children living in the vicinity of the main petrochemical complex located in the Gulf of Mexico, and explored the modulation by genetic polymorphisms of PAH excretion and related DNA damage. The participants (n=82) were children aged 6-10y attending schools near the industrial area. Urinary 1-hydroxypyrene (1-OHP; a biomarker of PAH exposure) was determined by reverse-phase-HPLC; DNA damage by the comet assay (Olive Tail Moment (OTM) parameter); CYP1A1*2C and CYP1B1*3 polymorphisms by real time-PCR; and GSTM1*0 and GSTT1*0 by multiplex PCR. The median value of 1-OHP was 0.37μmol/mol creatinine; 59% of children had higher 1-OHP concentrations than those reported in environmentally exposed adults (0.24μmol/mol creatinine). A stratified analysis showed increased DNA damage in children with 1-OHP concentrations greater than the median value. We observed higher 1-OHP concentrations in children with CYP1A1*2C or GSTM1*0 polymorphisms, and a positive influence of CYP1A1*2C on OTM values in children with the highest PAH exposure. The data indicate that children living in the surroundings of petrochemical industrial areas are exposed to high PAH levels, contributing to DNA damage and suggesting an increased health risk; furthermore, data suggest that polymorphisms affecting activation enzymes may modulate PAH metabolism and toxicity. Copyright © 2012 Elsevier B.V. All rights reserved.

Biotechnological procedures to select white rot fungi for the degradation of PAHs.

PubMed

Lee, Hwanhwi; Jang, Yeongseon; Choi, Yong-Seok; Kim, Min-Ji; Lee, Jaejung; Lee, Hanbyul; Hong, Joo-Hyun; Lee, Young Min; Kim, Gyu-Hyeok; Kim, Jae-Jin

2014-02-01

White rot fungi are essential in forest ecology and are deeply involved in wood decomposition and the biodegradation of various xenobiotics. The fungal ligninolytic enzymes involved in these processes have recently become the focus of much attention for their possible biotechnological applications. Successful bioremediation requires the selection of species with desirable characteristics. In this study, 150 taxonomically and physiologically diverse white rot fungi, including 55 species, were investigated for their performance in a variety of biotechnological procedures, such as dye decolorization, gallic acid reaction, ligninolytic enzymes, and tolerance to four PAHs, phenanthrene, anthracene, fluoranthene, and pyrene. Among these fungi, six isolates showed the highest (>90%) tolerance to both individual PAH and mixed PAHs. And six isolates oxidized gallic acid with dark brown color and they rapidly decolorized RBBR within ten days. These fungi revealed various profiles when evaluated for their biotechnological performance to compare the capability of degradation of PAHs between two groups selected. As the results demonstrated the six best species selected from gallic acid more greatly degraded four PAHs than the other isolates selected via tolerance test. It provided that gallic acid reaction test can be performed to rank the fungi by their ability to degrade the PAHs. Most of all, Peniophora incarnata KUC8836 and Phlebia brevispora KUC9033 significantly degraded the four PAHs and can be considered prime candidates for the degradation of xenobiotic compounds in environmental settings. Copyright © 2013 Elsevier B.V. All rights reserved.

Leaching of PAHs from agricultural soils treated with oil shale combustion ash: an experimental study.

PubMed

Jefimova, Jekaterina; Adamson, Jasper; Reinik, Janek; Irha, Natalya

2016-10-01

The present study focuses on the fate of polycyclic aromatic hydrocarbons (PAHs) in soils amended with oil shale ash (OSA). Leachability studies to assess the release of PAHs to the environment are essential before the application of OSA in agriculture. A quantitative estimation of the leaching of PAHs from two types of soil and two types of OSA was undertaken in this study. Two leaching approaches were chosen: (1) a traditional one step leaching scheme and (2) a leaching scheme with pretreatment, i.e.., incubation of the material in wet conditions imitating the field conditions, followed by a traditional leaching procedure keeping the total amount of water constant. The total amount of PAHs leached from soil/OSA mixtures was in the range of 15 to 48 μg/kg. The amount of total PAHs leached was higher for the incubation method, compared to the traditional leaching method, particularly for Podzolic Gleysols soil. This suggests that for the incubation method, the content of organic matter and clay minerals of the soil influence the fate of PAHs more strongly compared to the traditional leaching scheme. The amount of PAHs leached from OSA samples is higher than from soil/OSA mixtures, which suggests soils to inhibit the release of PAHs. Calculated amount of PAHs from experimental soil and OSA leaching experiments differed considerably from real values. Thus, it is not possible to estimate the amount of PAHs leached from soil/OSA mixtures based on the knowledge of the amount of PAHs leached from soil and OSA samples separately.

Analysis of a PAH-degrading bacterial population in subsurface sediments on the Mid-Atlantic Ridge

NASA Astrophysics Data System (ADS)

Shao, Zongze; Cui, Zhisong; Dong, Chunming; Lai, Qiliang; Chen, Liang

2010-05-01

Little is known about the types and concentrations of polycyclic aromatic hydrocarbons (PAHs) existing in the deep-sea subsurface environment, which is believed to be cold, oligothrophic and of high static pressure. PAHs in the upper layers of the water column are unavoidably subjected to degradation while they are deposited to the sea floor and become embedded in the deep-sea sediment. In this report, a high concentration of PAHs was discovered in the sediment 2.7 m beneath the bottom surface at a water depth of 3962 m on the Mid-Atlantic Ridge (MAR). The total concentration of PAHs was 445 ng (g dry wt sediment) -1. Among the seven detected PAHs, the concentrations of phenanthrene (222 ng g -1) and fluorene (79 ng g -1) were relatively high. In addition, PAH-degrading bacteria were found within the sediments. As in a previously detected site on the MAR, in the PAH-enriched region of this site, a bacterium of the genus Cycloclasticus was found to be the predominant isolate detected by PCR-DGGE analysis. In addition, bacteria of the Halomonas, Marinobacter, Alcanivorax, Thalassospira and Maricaulis genera, were also included in the PAH-degrading community. In summary, a high concentration of PAHs was detected in the subsurface of the deep-sea sediment, and once again, the Cycloclasticus bacterium was confirmed to be a ubiquitous marine PAH degrader even in the subsurface marine environment. Considering the abundance of PAHs therein, biodegradation is thus thought to be inactive, probably because of the low temperature, limited oxygen and/or limited nutrients.

Temporal variability of Polycyclic Aromatic Hydrocarbons (PAHs) in a receptor site of the Puebla-Tlaxcala Valley

NASA Astrophysics Data System (ADS)

Padilla, Z. V.; Torres, R.; Ruiz Suarez, L.; Molina, L. T.

2013-05-01

This contribution documents the presence and possible origin of PAHs, their temporal concentration patterns and correlations with other air pollutants in the so-called Puebla-Tlaxcala valley. This valley is located to the east of the Mexico City Metropolitan Area and is a very populated region which suffers of air pollution problems. Emission sources of PAHs include open burning, industrial boilers, automobiles and trucks, but vehicle emissions vary significantly depending on the use of: fuel, engine type and catalytic converter. An important emission source in the Puebla-Tlaxcala region is wood burning for cooking. Therefore, it is expected to have contributions of PAHS from this type of sources. PAHs measurements were performed in an air pollution semi-rural receptor site (Chipilo) southwest the City of Puebla, using an aerosol photoelectric sensor (PAS 2000 CE) to measure the concentration of PAHs and a diffuser charger (DC 2000 CE) to evaluate the active surface (DC) of the particles. The measuring period included March and April of 2012 during the ozne season in central Mexico. The use of these two sensors in parallel has been identified as a fingerprint technique to identify different types of particles from several combustion processes and is a useful tool to identify quantitatively the major source of emissions, as well as to describe thephysical and chemical characteristics of the particles. Correlations between PAHs and DC, with NOx and CO, together with an analysis of atmospheric transport may approximate the possible origin of these particles. The coefficient PAHs / DC associated with backward trajectory analysis represents a tool to identify potential areas of emission. The correlation between PAHs and NOx emissions reflects association with diesel combustion, while the correlation between PAHs and CO, the combustion of gasoline. The results show that vehicle emissions are the major source of PAHs with an associated increase in the concentration of

NHEXAS PHASE I MARYLAND STUDY--PAHS IN AIR ANALYTICAL RESULTS

EPA Science Inventory

The PAHs in Air data set contains analytical results for measurements of up to 11 PAHs in 127 air samples over 51 households. Twenty-four-hour samples were taken over a one-week period using a continuous pump and solenoid apparatus pumping a standardized air volume through an UR...

Polycyclic aromatic hydrocarbons (PAHs) in the water column and sediment core of Deep Bay, South China

NASA Astrophysics Data System (ADS)

Qiu, Yao-Wen; Zhang, Gan; Liu, Guo-Qing; Guo, Ling-Li; Li, Xiang-Dong; Wai, Onyx

2009-06-01

The levels of 15 polycyclic aromatic hydrocarbons (PAHs) were determined in seawater, suspended particulate matter (SPM), surface sediment and core sediment samples of Deep Bay, South China. The average concentrations Σ 15PAHs were 69.4 ± 24.7 ng l -1 in seawater, 429.1 ± 231.8 ng g -1 in SPM, and 353.8 ± 128.1 ng g -1 dry weight in surface sediment, respectively. Higher PAH concentrations were observed in SPM than in surface sediment. Temporal trend of PAH concentrations in core sediment generally increased from 1948 to 2004, with higher concentrations in top than in sub-surface, implying a stronger recent input of PAHs owing to the rapid economic development in Shenzhen. Compared with historical data, the PAH levels in surface sediment has increased, and this was further confirmed by the increasing trend of PAHs in the core sediment. Phenanthrene, fluoranthene and pyrene dominated in the PAH composition pattern profiles in the Bay. Compositional pattern analysis suggested that PAHs in the Deep Bay were derived from both pyrogenic and petrogenic sources, and diesel oil leakage, river runoff and air deposition may serve as important pathways for PAHs input to the Bay. Significant positive correlations between partition coefficient in surface sediment to that in water ( KOC) of PAH and their octanol/water partition coefficients ( KOW) were observed, suggesting that KOC of PAHs in sediment/water of Deep Bay may be predicted by the corresponding KOW.

High Voltage Electrochemiluminescence (ECL) as a New Method for Detection of PAH During Screening for PAH-Degrading Microbial Consortia.

PubMed

Staninska, Justyna; Szczepaniak, Zuzanna; Staninski, Krzysztof; Czarny, Jakub; Piotrowska-Cyplik, Agnieszka; Nowak, Jacek; Marecik, Roman; Chrzanowski, Łukasz; Cyplik, Paweł

The search for new bacterial consortia capable of removing PAH from the environment is associated with the need to employ novel, simple, and economically efficient detection methods. A fluorimetric method (FL) as well as high voltage electrochemiluminescence (ECL) on a modified surface of an aluminum electrode were used in order to determine the changes in the concentrations of PAH in the studied aqueous solutions. The ECL signal (the spectrum and emission intensity for a given wavelength) was determined with the use of an apparatus operating in single photon counting mode. The dependency of ECL and FL intensity on the concentration of naphthalene, phenanthrene, and pyrene was linear in the studied concentration range. The biodegradation kinetics of the particular PAH compounds was determined on the basis of the obtained spectroscopic determinations. It has been established that the half-life of naphthalene, phenanthrene, and pyrene at initial concentrations of 50 mg/l (beyond the solubility limit) reached 41, 75, and 130 h, accordingly. Additionally, the possibility of using ECL for rapid determination of the soluble fraction of PAH directly in the aqueous medium has been confirmed. Metagenomic analysis of the gene encoding 16S rRNA was conducted on the basis of V4 hypervariable region of the 16S rRNA gene and allowed to identify 198 species of bacteria that create the S4consortium. The consortium was dominated by Gammaproteobacteria (78.82 %), Flavobacteria (9.25 %), Betaproteobacteria (7.68 %), Sphingobacteria (3.76 %), Alphaproteobacteria (0.42 %), Clostridia (0.04 %), and Bacilli (0.03 %).

Recent Progress in DIB Research: Survey of PAHS and DIBS

NASA Technical Reports Server (NTRS)

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

2013-01-01

The spectra of several neutral and ionized PAHs isolated in the gas phase at low temperature have been measured in the laboratory under experimental conditions that mimic interstellar conditions and are compared with an extensive set of astronomical spectra of reddened, early type stars [1, 2]. The comparisons of astronomical and laboratory data provide upper limits for the abundances of specific neutral PAH molecules and ions along specific lines-of-sight. Something that is not attainable from infrared observations alone. We present the characteristics of the laboratory facility (COSmIC) that was developed for this study and discuss the findings resulting from the comparison of these unique laboratory data with high resolution, high S/N ratio astronomical observations. COSmIC combines a supersonic free jet expansion with discharge plasma and high-sensitivity cavity ringdown spectroscopy and provides experimental conditions that closely mimic the interstellar conditions. The column densities of the individual neutral PAH molecules and ions probed in these surveys are derived from the comparison of these unique laboratory data with high resolution, high S/N ratio astronomical observations. The comparisons of astronomical and laboratory data lead to clear and unambiguous conclusions regarding the expected abundances for PAHs of various sizes and charge states in the interstellar environments probed in the surveys. Band profile comparisons between laboratory and astronomical spectra lead to information regarding the molecular structures and characteristics associated with the DIB carriers in the corresponding lines-of-sight. These quantitative surveys of neutral and ionized PAHs in the optical range open the way for unambiguous quantitative searches of PAHs and complex organics in a variety of interstellar and circumstellar environments.

Polycyclic aromatic hydrocarbons (PAHs) in atmospheric dustfall from the industrial corridor in Hubei Province, Central China.

PubMed

Zhang, Jiaquan; Qu, Chengkai; Qi, Shihua; Cao, Junji; Zhan, Changlin; Xing, Xinli; Xiao, Yulun; Zheng, Jingru; Xiao, Wensheng

2015-10-01

Thirty atmospheric dustfall samples collected from an industrial corridor in Hubei Province, central China, were analyzed for 16 USEPA priority polycyclic aromatic hydrocarbons (PAHs) to investigate their concentrations, spatial distributions, sources, and health risks. Total PAH concentrations (ΣPAHs) ranged from 1.72 to 13.17 µg/g and averaged 4.91 µg/g. High molecular weight (4-5 rings) PAHs averaged 59.67% of the ΣPAHs. Individual PAH concentrations were not significantly correlated with total organic carbon, possibly due to the semi-continuous inputs from anthropogenic sources. Source identification studies suggest that the PAHs were mainly from motor vehicles and biomass/coal combustion. The incremental lifetime cancer risks associated with exposure to PAHs in the dustfall ranged from 10(-4) to 10(-6); these indicate potentially serious carcinogenic risks for exposed populations in the industrial corridor.

Accumulation, Allocation, and Risk Assessment of Polycyclic Aromatic Hydrocarbons (PAHs) in Soil-Brassica chinensis System

PubMed Central

Zhang, Juan; Fan, Shukai; Du, Xiaoming; Yang, Juncheng; Wang, Wenyan; Hou, Hong

2015-01-01

Farmland soil and leafy vegetables accumulate more polycyclic aromatic hydrocarbons (PAHs) in suburban sites. In this study, 13 sampling areas were selected from vegetable fields in the outskirts of Xi’an, the largest city in northwestern China. The similarity of PAH composition in soil and vegetation was investigated through principal components analysis and redundancy analysis (RDA), rather than discrimination of PAH congeners from various sources. The toxic equivalent quantity of PAHs in soil ranged from 7 to 202 μg/kg d.w., with an average of 41 μg/kg d.w., which exceeded the agricultural/horticultural soil acceptance criteria for New Zealand. However, the cancer risk level posed by combined direct ingestion, dermal contact, inhalation of soil particles, and inhalation of surface soil vapor met the rigorous international criteria (1×10−6). The concentration of total PAHs was (1052±73) μg/kg d.w. in vegetation (mean±standard error). The cancer risks posed by ingestion of vegetation ranged from 2×10−5 to 2×10−4 with an average of 1.66×10−4, which was higher than international excess lifetime risk limits for carcinogens (1×10−4). The geochemical indices indicated that the PAHs in soil and vegetables were mainly from vehicle and crude oil combustion. Both the total PAHs in vegetation and bioconcentration factor for total PAHs (the ratio of total PAHs in vegetation to total PAHs in soil) increased with increasing pH as well as decreasing sand in soil. The total variation in distribution of PAHs in vegetation explained by those in soil reached 98% in RDA, which was statistically significant based on Monte Carlo permutation. Common pollution source and notable effects of soil contamination on vegetation would result in highly similar distribution of PAHs in soil and vegetation. PMID:25679782

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

PubMed

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

2001-11-12

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

Impacts of estuarine mixing on vertical dispersion of polycyclic aromatic hydrocarbons (PAHs) in a tide-dominated estuary.

PubMed

Liu, Feng; Hu, Shuai; Guo, Xiaojuan; Niu, Lixia; Cai, Huayang; Yang, Qingshu

2018-06-01

To examine the impacts of estuarine mixing on the dispersion of polycyclic aromatic hydrocarbons (PAHs), seasonal variations in the vertical distribution of dissolved PAHs in the Humen River mouth of the Pearl River Estuary, which is a tide-dominated estuary, were thoroughly examined. An analysis of the vertical distribution of the concentration, composition and sources of PAHs indicates enhanced mixing of PAHs in January relative to June, which is strongly related to seasonal variations in the magnitude of estuarine mixing. Furthermore, the vertical distribution of PAHs initially indicated an increase and then a decrease from the surface layer to the bottom layer. In general, estuarine mixing promotes the vertical dispersion of PAHs, causing a more even PAHs distribution, while salinity stratification can trap PAHs, resulting in higher PAHs concentrations. Our study indicates that salinity variability stimulates significant dynamic effects regarding the dispersion of PAHs within estuarine environments. Copyright © 2018 Elsevier Ltd. All rights reserved.

Particulate polycyclic aromatic hydrocarbons (PAH) in the atmosphere of Bizerte city, Tunisia.

PubMed

Ben Hassine, S; Hammami, B; Ben Ameur, W; El Megdiche, Y; Barhoumi, B; Driss, M R

2014-09-01

The particle-phase concentrations of polycyclic aromatic hydrocarbons (PAH) were determined in 13 air samples collected in an urban area of Bizerte (Tunisia) during 2009-2010. Atmospheric particulate samples were extracted by ultrasonic bath and analyzed by high-performance liquid chromatography with fluorescence detection. PAH were found in all the analyzed air samples and the most abundant compounds were pyrene, fluoranthene, benzo[g,h,i]perylene, benzo[b]fluoranthene, chrysene and benzo[a]pyrene. ∑14-PAH concentrations ranging from 9.38 to 44.81 ng m(-3) with mean value of 25.39 ng m(-3). PAH diagnostic ratio source analysis revealed gasoline and diesel vehicular emissions as major sources. The mean total benzo[a]pyrene toxicity equivalent calculated for samples was 3.66 ng m(-3) and the mean contribution of the carcinogenic potency of benzo[a]pyrene was determined to be 55.8 %. Concentrations of particulate PAH in Bizerte city atmosphere were approximately eight times greater than sampled at a nearby rural site.

PAH Interactions with Soil and Effects on Bioaccessibility and Bioavailability to Humans

DTIC Science & Technology

2017-02-01

FINAL REPORT PAH Interactions with Soil and Effects on Bioaccessibility and Bioavailability to Humans SERDP Project ER-1743 FEBRUARY...COVERED (From - To) 2010-2017 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER W912HQ-10-C-0010 PAH Interactions with Soil and Effects on Bioaccessibility...assessments and remedial decisions to focus research where it can be most effective ; Task 2) Develop an understanding of the mechanisms by which PAHs

Relation Between PAHs and Coal-Tar-Based Pavement Sealant in Urban Environments (Invited)

NASA Astrophysics Data System (ADS)

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

2010-12-01

Since 2003, coal-tar-based sealant products have come under increased scrutiny as a source of PAHs in urban environments. Sealant (or sealcoat) is the black, shiny substance often applied to asphalt pavement, in particular parking lots and driveways, for esthetic and maintenance purposes. Coal-tar-based sealant, one of the two primary pavement sealant types on the market, typically is 20-35 percent coal-tar pitch, a known carcinogen that is more than 50 percent polycyclic aromatic hydrocarbons (PAHs). The PAH content of the coal-tar-based sealant product is about 1,000 times that of a similar, asphalt-based product, on average. This difference is reflected in regional differences in sealant use and PAH concentrations in pavement dust. In the central and eastern U.S., where the coal-tar-based formulation is prevalent, ΣPAH in mobile particles from sealed pavement have been shown to be about 1,000 times higher than in the western U.S., where the asphalt-based formulation is prevalent (the median ΣPAH concentrations are 2,200 mg/kg in the central and eastern U.S. and 2.1 mg/kg in the western U.S.). Source apportionment modeling indicates that, in the central and eastern U.S., particles from sealed pavement are contributing the majority of the PAHs in recently deposited (post-1990) lake sediment, with implications for ecological health, and that coal-tar-based sealant is the primary cause of upward trends in PAHs in U.S. urban lakes. From the standpoint of human health, research indicates that mobile particles from parking lots with coal-tar-based sealant are tracked indoors, resulting in elevated PAH concentrations in house dust. Coal-tar-based sealcoat being applied to an asphalt parking lot at the University of Texas Pickle Research Center.

Destruction of PAHs by X-Rays in circumnuclear regions of AGNs

NASA Astrophysics Data System (ADS)

Monfredini, T.; Wolff, W.; Boechat-Roberty, H. M.; Sales, D. A.; Pastoriza, M. G.

2017-07-01

Emission bands associated with PAH molecules are observed in the direction of some classes of AGNs like Seyfert 2, LINERs and obscured quasars (e.g. Kaneda et al., 2008, Sansigre et al., 2008 and Sales et al. 2013). The molecular stability in these environments suggest the presence of very dense gas (˜ 1023-24 cm-2) to shield the cloud of PAHs against X-ray radiation (Voit, 1992, Tielens, 2011, Sales et al., 2013). We examined the photochemistry of simple PAHs: naphtalene (C10H8), anthracene (C14H10), methyl-anthracene (C15H12) and pyrene (C16H10) at the photon energies of 275 eV, 310 eV, 1900 eV and 2500 eV in order to apply the findings at the AGN scenario. The absolute single and double photoionization and photodissociation cross sections were determined for each molecule at each energy. Their ionization and destruction induced by X-rays were examined in the conditions of the circumnuclear region of NGC 1808, a Seyfert 2 galaxy, where PAH emission was detected at 26 pc from the central object (Sales et al., 2013). It was verified the higher photostability of PAHs without functional groups attached. At higher photon energies, the results suggest a higher production yield of double charged PAHs in comparision with the single charged ones (e.g., 2 × higher for double ionized naphtalene at 2500 eV). The production of double charged molecules increase with the size of the molecules. We also discuss a minimum formation rate of PAH to balance the photodestruction rate and maintain a minimum density for their detection (e.g. 4,0× 10-7 M⊙ year-1 for a column density NH of 1023 cm-2 at 26 pc).

Assessment of PAHs levels in some fish and seafood from different coastal waters in the Niger Delta.

PubMed

Nwaichi, E O; Ntorgbo, S A

2016-01-01

Levels of sixteen polycyclic aromatic hydrocarbons (PAHs) in 30 edible tissues of selected frequently-consumed fish and seafood collected from three coastal waters of Niger Delta, namely, Sime, Kporghor and Iko were investigated in 2014. Gas chromatographic analysis were employed for PAHs determination. Observed mean PAHs levels in the samples ranged from below detection limit (BD) of analytical instrument to 22.400 ± 0.050 μg kg -1 wet wt. in Littorina littorea, BD to 87.400 ± 0.030 μg kg -1 wet wt. in Crassostrea virginica and from BD to 171.000 ± 0.430 μg kg -1 wet wt. in Periophthalmus koeleuteri. The highest average concentration of 171.000 ± 0.430 μg kg -1 wet wt. was recorded for Indeno [1,2,3-cd]pyrene from Sime water. High molecular weight PAHs (HMW-PAHs) were generally predominant compared to low molecular weight PAHs (LMW-PAHs). The LMW- PAH/HMW-PAH ratio was <1 for all species, indicating anthropogenic origin of PAHs in the coastal waters of Niger Delta environment. Moreover, the study of the PAHs fingerprints, using specific ratios, suggests the predominance of a pyrolytic origin for observed PAHs.

[Health risk assessment of coke oven PAHs emissions].

PubMed

Bo, Xin; Wang, Gang; Wen, Rou; Zhao, Chun-Li; Wu, Tie; Li, Shi-Bei

2014-07-01

Polycyclic aromatic hydrocarbons (PAHs) produced by coke oven are with strong toxicity and carcinogenicity. Taken typical coke oven of iron and steel enterprises as the case study, the dispersion and migration of 13 kinds of PAHs emitted from coke oven were analyzed using AERMOD dispersion model, the carcinogenic and non-carcinogenic risks at the receptors within the modeling domain were evaluated using BREEZE Risk Analyst and the Human Health Risk Assessment Protocol for Hazardous Waste Combustion (HHRAP) was followed, the health risks caused by PAHs emission from coke oven were quantitatively evaluated. The results indicated that attention should be paid to the non-carcinogenic risk of naphthalene emission (the maximum value was 0.97). The carcinogenic risks of each single pollutant were all below 1.0E-06, while the maximum value of total carcinogenic risk was 2.65E-06, which may have some influence on the health of local residents.

Impact of Inoculation Protocols, Salinity, and pH on the Degradation of Polycyclic Aromatic Hydrocarbons (PAHs) and Survival of PAH-Degrading Bacteria Introduced into Soil

PubMed Central

Kästner, Matthias; Breuer-Jammali, Maren; Mahro, Bernd

1998-01-01

Degradation of polycyclic aromatic hydrocarbons (PAHs) and survival of bacteria in soil was investigated by applying different inoculation protocols. The soil was inoculated with Sphingomonas paucimobilis BA 2 and strain BP 9, which are able to degrade anthracene and pyrene, respectively. CFU of soil bacteria and of the introduced bacteria were monitored in native and sterilized soil at different pHs. Introduction with mineral medium inhibited PAH degradation by the autochthonous microflora and by the strains tested. After introduction with water (without increase of the pore water salinity), no inhibition of the autochthonous microflora was observed and both strains exhibited PAH degradation. PMID:9435090

ASSESSING THE BIOAVAILABILITY OF PAHS IN FIELD-CONTAMINATED SEDIMENT USING XAD-2 ASSISTED DESORPTION

EPA Science Inventory

In the bioremediation of soils/sediments contaminated with polycyclic aromatic hydrocarbons (PAHs) it is imperative to determine the fraction of the PAHs that is amenable to remediation. For example, what fraction of the PAHs is available to the indigenous microorganisms, i.e. bi...

Aliphatic and polycyclic aromatic hydrocarbons (PAHs) in soils of the northwest Qinling Mountains: Patterns, potential risk and an appraisal of the PAH ratios to infer their source.

PubMed

Liu, Yanhong; Wu, Yingqin; Xia, Yanqing; Lei, Tianzhu; Tian, Chuntao; Hou, Xiaohuan

2017-03-21

Surface soils from the tourist areas of the northwest Qinling Mountains were analyzed to determine the concentrations, probable sources and potential risks of hydrocarbons. Concentrations of aliphatic and aromatic hydrocarbons ranged from 4.18 to 3240 ng g -1 and 0.0462 to 101 ng g -1 dry weight, respectively. The extent of soil contamination by hydrocarbons was generally typified by unpolluted to slightly polluted levels. The incremental lifetime cancer risks (ILCRs) for exposure to soil-borne PAHs indicated complete safety for tourists. Early diagenesis of natural products, bacteria activities and petroleum were the three main sources of aliphatic hydrocarbons, while the transport of air pollutants from pyrolytic processes was the main origin of PAHs. Because the photochemical reaction of PAHs in the atmosphere would produce lower ratios for Ant/(Ant + Phe), BaA/(BaA + Chr) and IcdP/(IcdP + BghiP), but a higher ratio for Fla/(Fla + Pyr), the source classification highly depended on the diagnostic ratios chosen. The plot of ΣCOM/Σ 13 PAH vs. ΣLMW/ΣHMW PAH provide additional information to distinguish the origins of PAHs, and it showed a cluster of pyrogenic sources except for sample JFS-8. Four sources were resolved by principal component analysis: (1) a low temperature pyrogenic process related to the use of fossil fuel and biomass, such as charcoal, straw and wood, which contributes 63.1% of the measured PAHs; (2) the potential contribution of diagenetic processes, contributing 18.4%; (3) traffic emissions, contributing 9.27%; and (4) bioconversion/bacterial action, contributing 5.82%. Additionally, there was a good exponential relationship (r 2 = 0.969) between the natural n-alkanes ratio (NAR) and carbon preference index for C 23 -C 35 (CPI 23-35 ) for all samples, which is of great use for the determination of the origins of aliphatic hydrocarbon.

Origins and fates of PAHs in the coastal marine environment off San Diego (California)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zeng, E.Y.; Yu, C.C.; Vista, C.L.

1995-12-31

The main inputs of anthropogenic hydrocarbons to the coastal marine environment off San Diego include the Point Lama wastewater outfall (City of San Diego), Tijuana River (crossing the boarder between the US and Mexico) and several storm drains along the coastline and in San Diego Bay, inadvertent spills, and aerial deposition. Samples collected (in January and June 1994) from the Point Loma wastewater effluent, Tijuana River runoff, and microlayer, sediment trap, and surface sediment at several locations adjacent to the Point Loma outfall, entrance of Tijuana River into the ocean, and San Diego Bay (near the San Diego International Airport)more » were analyzed to determine the origins and fates of PAHs in the coastal marine environment. Alkyl homologue distributions (AHDS) for naphthalene indicated a mainly petrogenic origin for low molecular-weight PAHs in the effluent, water column particle, and sediment near the outfall. Parent compound distributions (PCDS) for PAHs with molecular weights 178, 202, 228, 252, 276, and 278 showed combustion-related inputs in the water column particle and sediment, especially for mid to high molecular-weight PAHs. PAHs with molecular weight equal to or higher than 252 were not detected in the effluent. The compositions of PAHs were substantially different in the effluent particulates and filtrates, implying a great deal about the fates of PAHs from the outfall and their bioaccumulation by organisms. PAHs detected in Tijuana River runoff had similar AHDs and PCDs to those of the Point Loma outfall effluent. AHDs in the San Diego Bay sediment exhibited marked seasonal variation; low molecular-weight PAHs were significantly combustion-related in January and more petrogenic in June. Microlayer samples generally contained dominant combustion-generated PAHs. The impact of the wastewater outfall discharge on the nearby water column and sediment appeared compromised by other non-point source inputs.« less

VUV photo-processing of PAH cations: quantitative study on the ionization versus fragmentation processes

PubMed Central

Zhen, Junfeng; Castillo, Sarah Rodriguez; Joblin, Christine; Mulas, Giacomo; Sabbah, Hassan; Giuliani, Alexandre; Nahon, Laurent; Martin, Serge; Champeaux, Jean-Philippe; Mayer, Paul M.

2016-01-01

Interstellar polycyclic aromatic hydrocarbons (PAHs) are strongly affected by the absorption of vacuum ultraviolet (VUV) photons in the interstellar medium (ISM), yet the branching ratio between ionization and fragmentation is poorly studied. This is crucial for the stability and charge state of PAHs in the ISM in different environments, affecting in turn the chemistry, the energy balance, and the contribution of PAHs to the extinction and emission curves. We studied the interaction of PAH cations with VUV photons in the 7 – 20 eV range from the synchrotron SOLEIL beamline, DESIRS. We recorded by action spectroscopy the relative intensities of photo-fragmentation and photo-ionization for a set of eight PAH cations ranging in size from 14 to 24 carbon atoms, with different structures. At photon energies below ~13.6 eV fragmentation dominates for the smaller species, while for larger species ionization is immediately competitive after the second ionization potential (IP). At higher photon energies, all species behave similarly, the ionization yield gradually increases, leveling off between 0.8 and 0.9 at ~18 eV. Among isomers, PAH structure appears to mainly affect the fragmentation cross section, but not the ionization cross section. We also measured the second IP for all species and the third IP for two of them, all are in good agreement with theoretical ones confirming that PAH cations can be further ionized in the diffuse ISM. Determining actual PAH dication abundances in the ISM will require detailed modeling. Our measured photo-ionization yields for several PAH cations provide a necessary ingredient for such models. PMID:27212712

VUV photo-processing of PAH cations: quantitative study on the ionization versus fragmentation processes.

PubMed

Zhen, Junfeng; Castillo, Sarah Rodriguez; Joblin, Christine; Mulas, Giacomo; Sabbah, Hassan; Giuliani, Alexandre; Nahon, Laurent; Martin, Serge; Champeaux, Jean-Philippe; Mayer, Paul M

2016-05-10

Interstellar polycyclic aromatic hydrocarbons (PAHs) are strongly affected by the absorption of vacuum ultraviolet (VUV) photons in the interstellar medium (ISM), yet the branching ratio between ionization and fragmentation is poorly studied. This is crucial for the stability and charge state of PAHs in the ISM in different environments, affecting in turn the chemistry, the energy balance, and the contribution of PAHs to the extinction and emission curves. We studied the interaction of PAH cations with VUV photons in the 7 - 20 eV range from the synchrotron SOLEIL beamline, DESIRS. We recorded by action spectroscopy the relative intensities of photo-fragmentation and photo-ionization for a set of eight PAH cations ranging in size from 14 to 24 carbon atoms, with different structures. At photon energies below ~13.6 eV fragmentation dominates for the smaller species, while for larger species ionization is immediately competitive after the second ionization potential (IP). At higher photon energies, all species behave similarly, the ionization yield gradually increases, leveling off between 0.8 and 0.9 at ~18 eV. Among isomers, PAH structure appears to mainly affect the fragmentation cross section, but not the ionization cross section. We also measured the second IP for all species and the third IP for two of them, all are in good agreement with theoretical ones confirming that PAH cations can be further ionized in the diffuse ISM. Determining actual PAH dication abundances in the ISM will require detailed modeling. Our measured photo-ionization yields for several PAH cations provide a necessary ingredient for such models.

Concentrations of Polycyclic Aromatic Hydrocarbons (PAHs) in Urban Stormwater, Madison, Wisconsin, 2005-08

USGS Publications Warehouse

Selbig, William R.

2009-01-01

Concentrations of 18 PAH compounds were characterized from six urban source areas (parking lots, feeder street, collector street, arterial street, rooftop, and strip mall) around Madison, Wisconsin. Parking lots were categorized into those that were or were not sealed. On average, chrysene, fluoranthene, and pyrene were the dominant PAH compounds in all urban stormwater samples. Geometric mean concentrations for most individual PAH compounds were significantly greater for a parking lot that was sealed than for lots that were not sealed. Results from this study are consistent with similar studies that measured PAH concentrations in urban stormwater samples in Marquette, Mich., and Madison, Wis.

Atmospheric deposition of polycyclic aromatic hydrocarbons (PAHs) in Shanghai: the spatio-temporal variation and source identification

NASA Astrophysics Data System (ADS)

Cheng, Chen; Bi, Chunjuan; Wang, Dongqi; Yu, Zhongjie; Chen, Zhenlou

2018-03-01

This study investigated the dry and wet deposition fluxes of atmospheric polycyclic aromatic hydrocarbons (PAHs) in Shanghai, China. The flux sources were traced based on composition and spatio-temporal variation. The results show that wet deposition concentrations of PAHs ranged from 0.07 to 0.67 mg·L-1 and were correlated with temperature ( P<0.05). Dry deposition of PAHs concentrations ranged from 3.60-92.15 mg·L-1 and were higher in winter and spring than in summer and autumn. The annual PAH average fluxes were 0.631 mg·m-2·d-1 and 4.06 mg·m-2·d-1 for wet and dry deposition, respectively. The highest wet deposition of PAH fluxes was observed in summer, while dry deposition fluxes were higher in winter and spring. Atmospheric PAHs were deposited as dry deposition in spring and winter, yet wet deposition was the dominant pathway during summer. Total atmospheric PAH fluxes were higher in the northern areas than in the southern areas of Shanghai, and were also observed to be higher in winter and spring. Annual deposition of atmospheric PAHs was about 10.8 t in across all of Shanghai. Wet deposition of PAHs was primarily composed of two, three, or four rings, while dry deposition of PAHs was composed of four, five, or six rings. The atmospheric PAHs, composed of four, five, or six rings, primarily existed in the form of particulates. Coal combustion and vehicle emissions were the dominant sources of PAH in the observed area of downtown Shanghai. In suburban areas, industrial pollution, from sources such as coke oven, incinerator, and oil fired power plant, was as significant as vehicle emissions in contributing to the deposition of PAHs.

PAH sorption mechanism and partitioning behavior in lampblack-impacted soils from former oil-gas plant sites.

PubMed

Hong, Lei; Ghosh, Upal; Mahajan, Tania; Zare, Richard N; Luthy, Richard G

2003-08-15

This study assessed polycyclic aromatic hydrocarbon (PAH) association and aqueous partitioning in lampblack-impacted field soils from five sites in California that formerly housed oil-gas process operations. Lampblack is the solid residue resulting from the decomposition of crude oil at high temperatures in the gas-making operation and is coated or impregnated with oil gasification byproducts, among which PAHs are the compounds of the greatest regulatory concern. A suite of complementary measurements investigated the character of lampblack particles and PAH location and the associated effects on PAH partitioning between lampblack and water. PAH analyses on both whole samples and density-separated components demonstrated that 81-100% of PAHs in the lampblack-impacted soils was associated with lampblack particles. FTIR, 13C NMR, and SEM analyses showed that oil-gas lampblack solids comprise primarily aromatic carbon with soot-like structures. A free-phase aromatic oil may be present in some of the lampblack soils containing high PAH concentrations. Comparable long-term aqueous partitioning measurements were obtained with an air-bridge technique and with a centrifugation/alum flocculation procedure. Large solid/water partition coefficient (Kd) values were observed in samples exhibiting lower PAH and oil levels, whereas smaller Kd values were measured in lampblack samples containing high PAH levels. The former result is in agreement with an oil-soot partitioning model, and the latter is in agreement with a coal tar-water partitioning model. Lampblack containing high PAH levels appears to exhaust the sorption capacity of the soot-carbon, creating a free aromatic oil phase that exhibits partitioning behavior similar to PAHs in coal tar. This study improves mechanistic understanding of PAH sorption on aged lampblack residuals at former oil-gas sites and provides a framework for mechanistic assessment of PAH leaching potential and risk from such site materials.

Review of the quantification techniques for polycyclic aromatic hydrocarbons (PAHs) in food products.

PubMed

Bansal, Vasudha; Kumar, Pawan; Kwon, Eilhann E; Kim, Ki-Hyun

2017-10-13

There is a growing need for accurate detection of trace-level PAHs in food products due to the numerous detrimental effects caused by their contamination (e.g., toxicity, carcinogenicity, and teratogenicity). This review aims to discuss the up-to-date knowledge on the measurement techniques available for PAHs contained in food or its related products. This article aims to provide a comprehensive outline on the measurement techniques of PAHs in food to help reduce their deleterious impacts on human health based on the accurate quantification. The main part of this review is dedicated to the opportunities and practical options for the treatment of various food samples and for accurate quantification of PAHs contained in those samples. Basic information regarding all available analytical measurement techniques for PAHs in food samples is also evaluated with respect to their performance in terms of quality assurance.

Uptake of PAHs into polyoxymethylene and application to oil-soot (lampblack)-impacted soil samples.

PubMed

Hong, Lei; Luthy, Richard G

2008-05-01

Polyoxymethylene (POM) is a polymeric material used increasingly in passive sampling of hydrophobic organic contaminants such as PAHs and PCBs in soils and sediments. In this study, we examined the sorption behavior of 12 PAH compounds to POM and observed linear isotherms spanning two orders of magnitude of aqueous concentrations. Uptake kinetic studies performed in batch systems for up to 54 d with two different volume ratios of POM-to-aqueous phase were evaluated with coupled diffusion and mass transfer models to simulate the movement of PAHs during the uptake process and to assess the physicochemical properties and experimental conditions that control uptake rates. Diffusion coefficients of PAHs in POM were estimated to be well correlated with diffusants' molecular weights as D(POM) proportional, variant(MW)(-3), descending from 2.3 x 10(-10) cm(2) s(-1) for naphthalene to 7.0 x 10(-11) cm(2) s(-1) for pyrene. The uptake rates for PAHs with log K(ow)<5.8 were controlled by the POM phase and the hydrophobicity of PAH compounds. For more hydrophobic PAH compounds, the aqueous boundary layer played an increasingly important role in determining the overall mass transfer rate. The POM partitioning technique was demonstrated to agree well with two other procedures for measuring PAH soil-water distribution coefficients in oil-soot (lampblack) containing soil samples.

[Ex-situ remediation of PAHs contaminated site by successive methyl-beta-cyclodextrin enhanced soil washing].

PubMed

Sun, Ming-Ming; Teng, Ying; Luo, Yong-Ming; Li, Zhen-Gao; Jia, Zhong-Jun; Zhang, Man-Yun

2013-06-01

Polycyclic aromatic hydrocarbon (PAH) polluted sites caused by abandoned coking plants have attracted great attentions. This study investigated the feasibility of using methyl-beta-cyclodextrin (MCD) solution to enhance ex situ soil washing for extracting PAHs. Treatment with elevated temperature (50 degrees C) in combination with ultrasonication (35 kHz, 30 min) at 100 g x L(-1) was effective. It was found that 96.7% +/- 2.4% of 3-ring PAH, 89.7% +/- 3.2% of 4-ring PAH, 76.3% +/- 2.2% of 5 (+6)-ring PAH and 91.3% +/- 3.1% of total PAHs were removed from soil after five successive washing cycles. The desorption kinetics of PAHs from contaminated soil was determined before and after successive washings. The 400 h Tenax extraction of PAHs from soil was decreasing gradually with increasing washing times. Furthermore, the F(r), F(sl), k(r), k(sl) and k(vl) were significantly lower than those of CK (P < 0.01). Therefore, considering the removal efficiency and potential environmental risk after soil )ashing, successive washing three times was selected as a reasonable parameter. These results have practical implications for site risk assessment and cleanup strategies.

Exposure Assessment of Polycyclic Aromatic Hydrocarbon (PAHs) in Childcare Centers of Muang, Nakhon Ratchasima

NASA Astrophysics Data System (ADS)

Jitlada, C.; Pentamwa, P.

2018-03-01

This study aims to characterize airborne polycyclic aromatic hydrocarbons (PAHs) as of particulate and vapor phases variation. The samples were collected from the childcare centers where divided into urban and rural areas in Nakhon Ratchasima Province of Thailand. The airborne samples were collected from five childcare centers during the dry season in the year 2017. The PAHs species were determined by the gas chromatography and mass spectroscopy (GS/MS) method. Results show that the total concentrations of PAHs were higher than vapor phase that both similar in urban area and rural area. The dominant PAHs compounds of both urban and rural areas were benzo(a)pyrene, benzo(a,h)anthracene and indeno(1,2,3-cd)pyrene, respectively. Furthermore, the concentrations of PAHs in municipality (urban) childcare centers were higher than rural childcare centers area of Nakhon Ratchasima province. The risks associated with exposure to PAHs were evaluated using the TEF approach. The estimated value of lifetime lung cancer risks children in urban were significantly (p < 0.05) 2 times of children in rural, thus demonstrating that exposure to PAHs at levels found at urban site may be cause potential health risks.

Occurrence and distribution of Polycyclic aromatic hydrocarbons (PAHs) in seawater, sediments and corals from Hainan Island, China.

PubMed

Xiang, Nan; Jiang, Chunxia; Yang, Tinghan; Li, Ping; Wang, Haihua; Xie, Yanli; Li, Sennan; Zhou, Hailong; Diao, Xiaoping

2018-05-15

The levels of 16 US EPA priority polycyclic aromatic hydrocarbons (PAHs) were investigated in corals, ambient seawater and sediments of Hainan Island, China, using gas chromatography - mass spectrometry (GC-MS). The total PAHs (∑PAHs) concentrations ranged from 273.79 to 407.82ng/L in seawater. Besides, the concentrations of ∑PAHs in corals 333.88-727.03ng/g dw) were markedly (P < 0.05) higher than ambient sediments 67.29-196.99ng/g dw), demonstrating the bioaccumulation ability of PAHs by corals. The highest concentration of ∑PAHs was detected at site S2 in Pavona decussate, which also bore the highest ∑PAHs levels in both seawater and sediments. The massive corals were more enriched with PAHs than the branching corals. Although 2 and 3-ring PAHs were predominant and accounted for 69.27-80.46% of the ∑PAHs in corals and ambient environment, the levels of high molecular weight (HMW) PAHs (4-6 ring) in corals also demonstrated their potential dangers for corals and organisms around coral reefs. Biota-sediment accumulation factor (BSAF) refers to an index of the pollutant absorbed by aquatic organisms from the surrounding sediments. The poor correlation between log BSAF and log K ow (hydrophobicity) indicated that PAHs in corals maybe not bioaccumulate from the ambient sediments but through pathways like absorbing from seawater, symbiosis, and feeding. Based on our data, long-term ecological monitoring in typical coral reef ecosystems combined with ecotoxicological tests of PAHs on corals is necessary to determine the impacts of PAHs on coral reefs. Copyright © 2018 Elsevier Inc. All rights reserved.

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.

Occurrence and Risk Assessment of PAHs in Surface Sediments from Western Arctic and Subarctic Oceans

PubMed Central

Lin, Yan; Cai, Minggang; Zhang, Jingjing; Zhang, Yuanbiao; Kuang, Weiming; Liu, Lin; Huang, Peng; Ke, Hongwei

2018-01-01

In the fourth Chinese National Arctic Research Expedition (from July to September, 2010), 14 surface sediment samples were collected from the Bering Sea, Chukchi Sea, and Canadian Basin to examine the spatial distributions, potential sources, as well as ecological and health risk assessment of polycyclic aromatic hydrocarbons (PAHs). The ∑PAH (refers to the sum of 16 priority PAHs) concentration range from 27.66 ng/g to 167.48 ng/g (dry weight, d.w.). Additionally, the concentrations of ∑PAH were highest in the margin edges of the Canadian Basin, which may originate from coal combustion with an accumulation of Canadian point sources and river runoff due to the surface ocean currents. The lowest levels occurred in the northern of Canadian Basin, and the levels of ∑PAH in the Chukchi Sea were slightly higher than those in the Being Sea. Three isomer ratios of PAHs (Phenanthrene/Anthracene, BaA/(BaA+Chy), and LMW/HMW) were used to investigate the potential sources of PAHs, which showed the main source of combustion combined with weaker petroleum contribution. Compared with four sediment quality guidelines, the concentrations of PAH are much lower, indicating a low potential ecological risk. All TEQPAH also showed a low risk to human health. Our study revealed the important role of the ocean current on the redistribution of PAHs in the Arctic. PMID:29649142

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

NASA Astrophysics Data System (ADS)

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

2014-02-01

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

MEASURING AIRBORNE PAHS FROM THE NEW YORK WORLD TRADE CENTER DISASTER

EPA Science Inventory

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in ambient air, are suspected human carcinogens, and have been linked to genotoxic and mutagenic effects. Although there are no specific monitoring programs for PAHs in ambient air in the United States, there is a national...

Multivariate analysis of mixed contaminants (PAHs and heavy metals) at manufactured gas plant site soils.

PubMed

Thavamani, Palanisami; Megharaj, Mallavarapu; Naidu, Ravi

2012-06-01

Principal component analysis (PCA) was used to provide an overview of the distribution pattern of polycyclic aromatic hydrocarbons (PAHs) and heavy metals in former manufactured gas plant (MGP) site soils. PCA is the powerful multivariate method to identify the patterns in data and expressing their similarities and differences. Ten PAHs (naphthalene, acenapthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, chrysene, benzo[a]pyrene) and four toxic heavy metals - lead (Pb), cadmium (Cd), chromium (Cr) and zinc (Zn) - were detected in the site soils. PAH contamination was contributed equally by both low and high molecular weight PAHs. PCA was performed using the varimax rotation method in SPSS, 17.0. Two principal components accounting for 91.7% of the total variance was retained using scree test. Principle component 1 (PC1) substantially explained the dominance of PAH contamination in the MGP site soils. All PAHs, except anthracene, were positively correlated in PC1. There was a common thread in high molecular weight PAHs loadings, where the loadings were inversely proportional to the hydrophobicity and molecular weight of individual PAHs. Anthracene, which was less correlated with other individual PAHs, deviated well from the origin which can be ascribed to its lower toxicity and different origin than its isomer phenanthrene. Among the four major heavy metals studied in MGP sites, Pb, Cd and Cr were negatively correlated in PC1 but showed strong positive correlation in principle component 2 (PC2). Although metals may not have originated directly from gaswork processes, the correlation between PAHs and metals suggests that the materials used in these sites may have contributed to high concentrations of Pb, Cd, Cr and Zn. Thus, multivariate analysis helped to identify the sources of PAHs, heavy metals and their association in MGP site, and thereby better characterise the site risk, which would not be possible if one uses chemical analysis

Bioremediation of polyaromatic hydrocarbons (PAHs) using rhizosphere technology

PubMed Central

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

2015-01-01

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

The 11.2 μm emission of PAHs in astrophysical objects

NASA Astrophysics Data System (ADS)

Candian, A.; Sarre, P. J.

2015-04-01

The 11.2-μm emission band belongs to the family of the `unidentified' infrared emission bands seen in many astronomical environments. In this work, we present a theoretical interpretation of the band characteristics and profile variation for a number of astrophysical sources in which the carriers are subject to a range of physical conditions. The results of Density Functional Theory calculations for the solo out-of-plane vibrational bending modes of large polycyclic aromatic hydrocarbon (PAH) molecules are used as input for a detailed emission model which includes the temperature and mass dependence of PAH band wavelength, and a PAH mass distribution that varies with object. Comparison of the model with astronomical spectra indicates that the 11.2-μm band asymmetry and profile variation can be explained principally in terms of the mass distribution of neutral PAHs with a small contribution from anharmonic effects.

Remediation of PAH-contaminated soil by the combination of tall fescue, arbuscular mycorrhizal fungus and epigeic earthworms.

PubMed

Lu, Yan-Fei; Lu, Mang

2015-03-21

A 120-day experiment was performed to investigate the effect of a multi-component bioremediation system consisting of tall fescue (Festuca arundinacea), arbuscular mycorrhizal fungus (AMF) (Glomus caledoniun L.), and epigeic earthworms (Eisenia foetida) for cleaning up polycyclic aromatic hydrocarbons (PAHs)-contaminated soil. Inoculation with AMF and/or earthworms increased plant yield and PAH accumulation in plants. However, PAH uptake by tall fescue accounted for a negligible portion of soil PAH removal. Mycorrhizal tall fescue significantly enhanced PAH dissipation, PAH degrader density and polyphenol oxidase activity in soil. The highest PAH dissipation (93.4%) was observed in the combination treatment: i.e., AMF+earthworms+tall fescue, in which the soil PAH concentration decreased from an initial value of 620 to 41 mg kg(-1) in 120 days. This concentration is below the threshold level required for Chinese soil PAH quality (45 mg kg(-1) dry weight) for residential use. Copyright © 2014 Elsevier B.V. All rights reserved.

Impact of electrochemical treatment of soil washing solution on PAH degradation efficiency and soil respirometry.

PubMed

Mousset, Emmanuel; Huguenot, David; van Hullebusch, Eric D; Oturan, Nihal; Guibaud, Gilles; Esposito, Giovanni; Oturan, Mehmet A

2016-04-01

The remediation of a genuinely PAH-contaminated soil was performed, for the first time, through a new and complete investigation, including PAH extraction followed by advanced oxidation treatment of the washing solution and its recirculation, and an analysis of the impact of the PAH extraction on soil respirometry. The study has been performed on the remediation of genuine PAH-contaminated soil, in the following three steps: (i) PAH extraction with soil washing (SW) techniques, (ii) PAH degradation with an electro-Fenton (EF) process, and (iii) recirculation of the partially oxidized effluent for another SW cycle. The following criteria were monitored during the successive washing cycles: PAH extraction efficiency, PAH oxidation rates and yields, extracting agent recovery, soil microbial activity, and pH of soil. Two representative extracting agents were compared: hydroxypropyl-beta-cyclodextrin (HPCD) and a non-ionic surfactant, Tween(®) 80. Six PAH with different numbers of rings were monitored: acenaphthene (ACE), phenanthrene (PHE), fluoranthene (FLA), pyrene (PYR), benzo(a)pyrene (BaP), and benzo(g,h,i)perylene (BghiP). Tween(®) 80 showed much better PAH extraction efficiency (after several SW cycles) than HPCD, regardless of the number of washing cycles. Based on successive SW experiments, a new mathematical relation taking into account the soil/water partition coefficient (Kd*) was established, and could predict the amount of each PAH extracted by the surfactant with a good correlation with experimental results (R(2) > 0.975). More HPCD was recovered (89%) than Tween(®) 80 (79%), while the monitored pollutants were completely degraded (>99%) after 4 h and 8 h, respectively. Even after being washed with partially oxidized solutions, the Tween(®) 80 solutions extracted significantly more PAH than HPCD and promoted better soil microbial activity, with higher oxygen consumption rates. Moreover, neither the oxidation by-products nor the acidic media (p

Enhanced phytoremediation of soils contaminated with PAHs by arbuscular mycorrhiza and rhizobium.

PubMed

Ren, Cheng-Gang; Kong, Cun-Cui; Bian, Bian; Liu, Wei; Li, Yan; Luo, Yong-Ming; Xie, Zhi-Hong

2017-09-02

Greenhouse experiment was conducted to evaluate the potential effectiveness of a legume (Sesbania cannabina), arbuscular mycorrhizal fungi (AMF) (Glomus mosseae), and rhizobia (Ensifer sp.) symbiosis for remediation of Polycyclic aromatic hydrocarbons (PAHs) in spiked soil. AMF and rhizobia had a beneficial impact on each other in the triple symbiosis. AMF and/or rhizobia significantly increased plant biomass and PAHs accumulation in plants. The highest PAHs dissipation was observed in plant + AMF + rhizobia treated soil, in which >97 and 85-87% of phenanthrene and pyrene, respectively, had been degraded, whereas 81-85 and 72-75% had been degraded in plant-treated soil. During the experiment, a relatively large amount of water-soluble phenolic compounds was detected in soils of AMF and/or rhizobia treatment. It matches well with the high microbial activity and soil enzymes activity. These results suggest that the mutual interactions in the triple symbiosis enhanced PAHs degradation via stimulating both microbial development and soil enzyme activity. The mutual interactions between rhizobia and AMF help to improve phytoremediation efficiency of PAHs by S. cannabina.

Predicting toxicity to Hyalella azteca in pyrogenic-impacted sediments-Do we need to analyze for all 34 PAHs?

PubMed

Geiger, Stephen C; Azzolina, Nicholas A; Nakles, David V; Hawthorne, Steven B

2016-07-01

Polycyclic aromatic hydrocarbons (PAHs) are major drivers of risk at many urban and/or industrialized sediment sites. The US Environmental Protection Agency (USEPA) currently recommends using measurements of 18 parent + 16 groups of alkylated PAHs (PAH-34) to assess the potential for sediment-bound PAHs to impact benthic organisms at these sites. ASTM Method D7363-13 was developed to directly measure low-level sediment porewater PAH concentrations. These concentrations are then compared to ambient water criteria (final chronic values [FCVs]) to assess the potential for impact to benthic organisms. The interlaboratory validation study that was used to finalize ASTM D7363-13 was developed using 24 of the 2-, 3-, and 4-ring PAHs (PAH-24) that are included in the USEPA PAH-34 analyte list. However, it is the responsibility of the user of ASTM Method D7363 to establish a test method to quantify the remaining 10 higher molecular weight PAHs that make up PAH-34. These higher molecular weight PAHs exhibit extremely low saturation solubilities that make their detection difficult in porewater, which has proven difficult to implement in a contract laboratory setting. As a result, commercial laboratories are hesitant to conduct the method on the entire PAH-34 analyte list. This article presents a statistical comparison of the ability of the PAH-24 and PAH-34 porewater results to predict survival of the freshwater amphipod Hyalella azteca, using the original 269 sediment samples used to gain ASTM D7363 Method approval. The statistical analysis shows that the PAH-24 are statistically indistinguishable from the PAH-34 for predicting toxicity. These results indicate that the analysis of freely dissolved porewater PAH-24 is sufficient for making risk-based decisions based on benthic invertebrate toxicity (survival and growth). This reduced target analyte list should result in a cost-saving for stakeholders and broader implementation of the method at PAH-impacted sediment sites

The influence of sunlight and oxidative treatment on measured PAH concentrations in biochar.

PubMed

Khalid, Fathima N M; Klarup, Doug

2015-09-01

The concentration changes of 18 different polycyclic aromatic hydrocarbons (PAHs) in two different biochars were assessed after (1) chemical oxidative treatment with a solution of H2O2 and Na2S2O8, (2) exposure to sunlight with intermittent wetting, and (3) exposure to sunlight with intermittent wetting after mixing in ZnO and Na2S2O8. Chemical oxidative treatment of biochars derived from gasified wood biochar and a gasified wood/Arundo donax mixture led to decreases in six-ring PAHs, but overall significant increases in measured PAH concentration sums for both biochars (from 225 ± 7 to 312 ± 18 μg g(-1) for wood-derived and 165 ± 3 to 244 ± 7 μg g(-1) for mixture-derived). Sunlight exposure of the mixture-derived biochar led to increases in some three- and four-ring PAHs, but overall decreases in summed PAH concentrations (165 ± 3 to 60 ± 1 μg g(-1) with wetting only and 165 ± 3 to 41 ± 4 μg g(-1) when Na2S2O8 and ZnO were included). The mass losses in the sunlight-exposed samples primarily were due to losses of low molar mass (two-ring) PAHs, though high molar mass (five- and six-ring) PAH concentrations also decreased. This result implies sun and rain exposure to biochar, prior to agricultural application, will help reduce potential PAH soil contamination from the biochar.

A survey for PAH emission in H II regions, planetary and proto-planetary nebulae

NASA Technical Reports Server (NTRS)

Demuizon, M.; Cox, P.; Lequeux, J.

1989-01-01

The results of a systematic investigation of polycyclic aromatic hydrocarbon (PAH) emission in H II regions, planetary nebulae (PN), and proto-planetary nebulae (PNN), are reported. Data is obtained from the low resolution spectra (LRS) of IRAS. The results show that: PAHs are formed in carbon rich objects; and PAH emission is ubiquitous in general interstellar medium and requires the presence of ultraviolet photons, in planetary and proto-planetary nebulae, PAH emission is seen only where an ionizing flux is present and in carbon rich objects.

Sources, fate, and effects of PAHs in shallow water environments: a review with special reference to small watercraft

USGS Publications Warehouse

Albers, P.H.; Kennish, Michael J.

2002-01-01

Polycyclic aromatic hydrocarbons (PAHs) are aromatic hydrocarbons with two to seven fused carbon (benzene) rings that can have substituted groups attached. Shallow coastal, estuarine, lake, and river environments receive PAHs from treated wastewater, stormwater runoff, petroleum spills and natural seeps, recreational and commercial boats, natural fires, volcanoes, and atmospheric deposition of combustion products. Abiotic degradation of PAHs is caused by photooxidation, photolysis in water, and chemical oxidation. Many aquatic microbes, plants, and animals can metabolize and excrete ingested PAHs; accumulation is associated with poor metabolic capabilities, high lipid content, and activity patterns or distributions that coincide with high concentrations of PAHs. Resistance to biological transformation increases with increasing number of carbon rings. Four- to seven-ring PAHs are the most difficult to metabolize and the most likely to accumulate in sediments. Disturbance by boating activity of sediments, shorelines, and the surface microlayer of water causes water column re-entry of recently deposited or concentrated PAHs. Residence time for PAHs in undisturbed sediment exceeds several decades. Toxicity of PAHs causes lethal and sublethal effects in plants and animals, whereas some substituted PAHs and metabolites of some PAHs cause mutations, developmental malformations, tumors, and cancer. Environmental concentrations of PAHs in water are usually several orders of magnitude below levels that are acutely toxic, but concentrations can be much higher in sediment. The best evidence for a link between environmental PAHs and induction of cancerous neoplasms is for demersal fish in areas with high concentrations of PAHs in the sediment.

VUV PHOTO-PROCESSING OF PAH CATIONS: QUANTITATIVE STUDY ON THE IONIZATION VERSUS FRAGMENTATION PROCESSES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhen, Junfeng; Castillo, Sarah Rodriguez; Joblin, Christine

2016-05-10

Interstellar polycyclic aromatic hydrocarbons (PAHs) are strongly affected by the absorption of vacuum ultraviolet (VUV) photons in the interstellar medium (ISM), yet the branching ratio between ionization and fragmentation is poorly studied. This is crucial for the stability and charge state of PAHs in the ISM in different environments, affecting in turn the chemistry, the energy balance, and the contribution of PAHs to the extinction and emission curves. We studied the interaction of PAH cations with VUV photons in the 7–20 eV range from the synchrotron SOLEIL beamline, DESIRS. We recorded by action spectroscopy the relative intensities of photo-fragmentation andmore » photo-ionization for a set of eight PAH cations ranging in size from 14 to 24 carbon atoms, with different structures. At photon energies below ∼13.6 eV fragmentation dominates for the smaller species, while for larger species ionization is immediately competitive after the second ionization potential (IP). At higher photon energies all species behave similarly; the ionization yield gradually increases, leveling off between 0.8 and 0.9 at ∼18 eV. Among isomers, PAH structure appears to mainly affect the fragmentation cross section but not the ionization cross section. We also measured the second IP for all species and the third IP for two of them; all are in good agreement with theoretical ones, confirming that PAH cations can be further ionized in the diffuse ISM. Determining actual PAH dication abundances in the ISM will require detailed modeling. Our measured photo-ionization yields for several PAH cations provide a necessary ingredient for such models.« less

Seasonal changes, identification and source apportionment of PAH in PM1.0

NASA Astrophysics Data System (ADS)

Agudelo-Castañeda, Dayana Milena; Teixeira, Elba Calesso

2014-10-01

The objective of this research was to evaluate the seasonal variation of PAHs in PM1.0, as well as to identify and quantify the contributions of each source profile using the PMF receptor model. PM1.0 samples were collected on PTFE filters from August 2011 to July 2013 in the Metropolitan Area of Porto Alegre, Rio Grande do Sul, Brazil. The samples were extracted using the EPA method TO-13A and 16 Polycyclic Aromatic Hydrocarbons (PAHs) were analyzed using a gaseous chromatograph coupled with a mass spectrometer (GC-MS). Also, the data discussed in this study were analyzed to identify the relations of the PAHs concentrations with NOx, NO, O3 and meteorological parameters (temperature, solar radiation, wind speed, relative humidity). The results showed that in winter, concentrations of total PAHs were significantly higher than in summer, thus showing their seasonal variation. The identification of emission sources by applying diagnostic ratios confirmed that PAHs in the study area originate from mobile sources, especially, from diesel and gasoline emissions. The analysis by PMF receptor model showed the contribution of these two main sources of emissions, too, followed by coal combustion, incomplete combustion/unburned petroleum and wood combustion. The toxic equivalent factors were calculated to characterize the risk of cancer from PAH exposure to PM1.0 samples, and BaP and DahA dominated BaPeq levels.

Developmental toxicity of PAH mixtures in fish early life stages. Part II: adverse effects in Japanese medaka.

PubMed

Le Bihanic, Florane; Clérandeau, Christelle; Le Menach, Karyn; Morin, Bénédicte; Budzinski, Hélène; Cousin, Xavier; Cachot, Jérôme

2014-12-01

In aquatic environments, polycyclic aromatic hydrocarbons (PAHs) mostly occur as complex mixtures, for which risk assessment remains problematic. To better understand the effects of PAH mixture toxicity on fish early life stages, this study compared the developmental toxicity of three PAH complex mixtures. These mixtures were extracted from a PAH-contaminated sediment (Seine estuary, France) and two oils (Arabian Light and Erika). For each fraction, artificial sediment was spiked at three different environmental concentrations roughly equivalent to 0.5, 4, and 10 μg total PAH g(-1) dw. Japanese medaka embryos were incubated on these PAH-spiked sediments throughout their development, right up until hatching. Several endpoints were recorded at different developmental stages, including acute endpoints, morphological abnormalities, larvae locomotion, and genotoxicity (comet and micronucleus assays). The three PAH fractions delayed hatching, induced developmental abnormalities, disrupted larvae swimming activity, and damaged DNA at environmental concentrations. Differences in toxicity levels, likely related to differences in PAH proportions, were highlighted between fractions. The Arabian Light and Erika petrogenic fractions, containing a high proportion of alkylated PAHs and low molecular weight PAHs, were more toxic to Japanese medaka early life stages than the pyrolytic fraction. This was not supported by the toxic equivalency approach, which appeared unsuitable for assessing the toxicity of the three PAH fractions to fish early life stages. This study highlights the potential risks posed by environmental mixtures of alkylated and low molecular weight PAHs to early stages of fish development.

Isolation and characterization of bacteria capable of degrading polycyclic aromatic hydrocarbons (PAHs) and organophosphorus pesticides from PAH-contaminated soil in Hilo, Hawaii.

PubMed

Seo, Jong-Su; Keum, Young-Soo; Harada, Renee M; Li, Qing X

2007-07-11

Nineteen bacterial strains were isolated from petroleum-contaminated soil in Hilo, HI, and characterized by two different spray-plated methods, turbidity test in liquid medium, and 16S rRNA gene sequence analysis. Analysis of the soil showed 13 polycyclic aromatic hydrocarbons (PAHs) in a range from 0.6 to 30 mg/kg of dry weight each and 12 PAH metabolites. Five distinct bacterial strains (C3, C4, P1-1, JS14, and JS19b1) selected from preliminary plating and turbidity tests were further tested for PAH degradation through single PAH degradation assay. Strains C3, C4, and P1-1 degraded phenanthrene (40 mg/L) completely during 7 days of incubation. Strain JS14 degraded fluoranthene (40 mg/L) completely during 10 days of incubation. Strain JS19b1 degraded 100% of phenanthrene (40 mg/L) in 7 days, 77% of fluorene (40 mg/L) in 14 days, 97% of fluoranthene (40 mg/L) in 10 days, and 100% of pyrene (40 mg/L) in 14 days. Turbidity tests showed that strains P1-1, JS14, and JS19b1 utilized several organophosphorus pesticides as growth substrate. P1-1 can degrade carbofenothion, chlorfenvinphos, diazinon, fonofos, and pirimiphos-methyl. JS14 can transform chlorfenvinphos and diazinon. JS19b1 can break down diazinon, pirimiphos-methyl, and temephos.

Bioremediation mechanisms of combined pollution of PAHs and heavy metals by bacteria and fungi: A mini review.

PubMed

Liu, Shao-Heng; Zeng, Guang-Ming; Niu, Qiu-Ya; Liu, Yang; Zhou, Lu; Jiang, Lu-Hua; Tan, Xiao-Fei; Xu, Piao; Zhang, Chen; Cheng, Min

2017-01-01

In recent years, knowledge in regard to bioremediation of combined pollution of polycyclic aromatic hydrocarbons (PAHs) and heavy metals by bacteria and fungi has been widely developed. This paper reviews the species of bacteria and fungi which can tackle with various types of PAHs and heavy metals entering into environment simultaneously or successively. Microbial activity, pollutants bioavailability and environmental factors (e.g. pH, temperature, low molecular weight organic acids and humic acids) can all affect the bioremediation of PAHs and heavy metals. Moreover, this paper summarizes the remediation mechanisms of PAHs and heavy metals by microbes via elucidating the interaction mechanisms of heavy metals with heavy metals, PAHs/PAHs metabolites with PAHs and PAHs with heavy metals. Based on the above reviews, this paper also discusses the potential research needs for this field. Copyright © 2016 Elsevier Ltd. All rights reserved.

Photochemical degradation of hydroxy PAHs in ice: Implications for the polar areas.

PubMed

Ge, Linke; Li, Jun; Na, Guangshui; Chen, Chang-Er; Huo, Cheng; Zhang, Peng; Yao, Ziwei

2016-07-01

Hydroxyl polycyclic aromatic hydrocarbons (OH-PAHs) are derived from hydroxylated PAHs as contaminants of emerging concern. They are ubiquitous in the aqueous and atmospheric environments and may exist in the polar snow and ice, which urges new insights into their environmental transformation, especially in ice. In present study the simulated-solar (λ > 290 nm) photodegradation kinetics, products and pathways of four OH-PAHs (9-Hydroxyfluorene, 2-Hydroxyfluorene, 1-Hydroxypyrene and 9-Hydroxyphenanthrene) in ice were investigated, and the corresponding implications for the polar areas were explored. It was found that the kinetics followed the pseudo-first-order kinetics with the photolysis quantum yields (Φs) ranging from 7.48 × 10(-3) (1-Hydroxypyrene) to 4.16 × 10(-2) (2-Hydroxyfluorene). These 4 OH-PAHs were proposed to undergo photoinduced hydroxylation, resulting in multiple hydroxylated intermediates, particularly for 9-Hydroxyfluorene. Extrapolation of the lab data to the real environment is expected to provide a reasonable estimate of OH-PAH photolytic half-lives (t1/2,E) in mid-summer of the polar areas. The estimated t1/2,E values ranged from 0.08 h for 1-OHPyr in the Arctic to 54.27 h for 9-OHFl in the Antarctic. In consideration of the lower temperature and less microorganisms in polar areas, the photodegradation can be a key factor in determining the fate of OH-PAHs in sunlit surface snow/ice. To the best of our knowledge, this is the first report on the photodegradation of OH-PAHs in polar areas. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

PubMed

Martena, M J; Grutters, M M P; De Groot, H N; Konings, E J M; Rietjens, I M C M

2011-01-01

Food supplements can contain polycyclic aromatic hydrocarbons (PAH). The European Food Safety Authority (EFSA) has defined 16 priority PAH that are both genotoxic and carcinogenic and identified eight priority PAH (PAH8) or four of these (PAH4) as good indicators of the toxicity and occurrence of PAH in food. The current study aimed to determine benzo[a]pyrene and other EFSA priority PAH in different categories of food supplements containing botanicals and other ingredients. From 2003 to 2008, benzo[a]pyrene exceeded the limit of quantification (LOQ) in 553 (44%) of 1258 supplements with a lower-bound mean of 3.37 µg kg(-1). In 2008 and 2009, benzo[a]pyrene and 12 other EFSA priority PAH were determined in 333 food supplements. Benzo[a]pyrene exceeded the LOQ in 210 (63%) food supplements with a lower-bound mean of 5.26 µg kg(-1). Lower-bound mean levels for PAH4 and PAH8(-indeno[1,2,3-cd]pyrene) were 33.5 and 40.5 µg kg(-1), respectively. Supplements containing resveratrol, Ginkgo biloba, St. John's wort and propolis showed relatively high PAH4 levels in 2008 and 2009. Before 2008, supplements with these ingredients and also dong quai, green tea or valerian contained relatively high benzo[a]pyrene levels. On average, PAH4 intake resulting from food supplement use will be at the lower end of the range of contributions of main food groups to PAH4 exposure, although individual food supplements can contribute significantly to PAH4 exposure. Regular control of EFSA indicator PAH levels in food supplements may prove a way forward to reduce further the intake of PAH from food.

Effect of single and mixed polycyclic aromatic hydrocarbon contamination on plant biomass yield and PAH dissipation during phytoremediation.

PubMed

Afegbua, Seniyat Larai; Batty, Lesley Claire

2018-04-27

Polycyclic aromatic hydrocarbon (PAH)-contaminated sites have a mixture of PAH of varying concentration which may affect PAH dissipation differently to contamination with a single PAH. In this study, pot experiments investigated the impact of PAH contamination on Medicago sativa, Lolium perenne, and Festuca arundinacea biomass and PAH dissipation from soils spiked with phenanthrene (Phe), fluoranthene (Flu), and benzo[a]pyrene (B[a]P) in single and mixed treatments. Stimulatory or inhibitory effects of PAH contamination on plant biomass yields were not different for the single and mixed PAH treatments. Results showed significant effect of PAH treatments on plant growth with an increased root biomass yield for F. arundinacea in the Phe (175%) and Flu (86%) treatments and a root biomass decrease in the mixed treatment (4%). The mean residual PAHs in the planted treatments and unplanted control for the single treatments were not significantly different. B[a]P dissipation was enhanced for single and mixed treatments (71-72%) with F. arundinacea compared to the unplanted control (24-50%). On the other hand, B[a]P dissipation was inhibited with L. perenne (6%) in the single treatment and M. sativa (11%) and L. perenne (29%) in the mixed treatment. Abiotic processes had greater contribution to PAH dissipation compared to rhizodegradation in both treatments. In most cases, a stimulatory effect of PAH contamination on plant biomass yield without an enhancement of PAH dissipation was observed. Plant species among other factors affect the relative contribution of PAH dissipation mechanisms during phytoremediation. These factors determine the effectiveness and suitability of phytoremediation as a remedial strategy for PAH-contaminated sites. Further studies on impact of PAH contamination, plant selection, and rhizosphere activities on soil microbial community structure and remediation outcome are required.

Biliary PAH metabolites and the hepatosomatic index of brown bullheads from Lake Erie tributaries

USGS Publications Warehouse

Yang, X.; Baumann, P.C.

2006-01-01

In studies designed to investigate the environmental exposure of fish in Lake Erie tributaries, a benthic fish, the brown bullhead (Ameiurus nebulosus), was collected from the industrially contaminated Detroit River, Ottawa River, Black River, Cuyahoga River-harbor and -upstream, Ashtabula River, Buffalo River, and Niagara River, and the non-industrialized Old Woman Creek during 1997-2000. Biliary benzo[a]pyrene (B[a]P)- and naphthalene (NAPH)-type metabolites and the hepatosomatic index (HSI) were measured in fish and compared between different sites. Fish from all of the contaminated sites except Niagara River had significantly higher concentrations of both types of polycyclic aromatic hydrocarbon (PAH) metabolites than fish from the Old Woman Creek. Concentrations of PAH metabolites in bile of fish were positively associated with concentrations of PAHs in sediments, supporting the use of bile metabolites as a measure of PAH exposure. Relatively low concentrations of PAHs detected in fish bile and sediments of the Niagara River, which had undergone extensive remediation, suggested a lowered PAH exposure for fish at this site. No apparent trend was observed in HSI between the industrialized and non-industrialized sites. This study demonstrates that biliary PAH metabolites are an effective indicator of exposure of fish to PAHs. However, because factors other than contamination could also affect the liver size of wild fish, HSI alone may be not a reliable biomarker for assessing contaminant stress. ?? 2005 Elsevier Ltd. All rights reserved.

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

NASA Technical Reports Server (NTRS)

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

2010-01-01

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

Coal-Tar-Based Parking Lot Sealcoat: An Unrecognized Source of PAH to Settled House Dust

PubMed Central

2010-01-01

Despite much speculation, the principal factors controlling concentrations of polycyclic aromatic hydrocarbons (PAH) in settled house dust (SHD) have not yet been identified. In response to recent reports that dust from pavement with coal-tar-based sealcoat contains extremely high concentrations of PAH, we measured PAH in SHD from 23 apartments and in dust from their associated parking lots, one-half of which had coal-tar-based sealcoat (CT). The median concentration of total PAH (T-PAH) in dust from CT parking lots (4760 μg/g, n = 11) was 530 times higher than that from parking lots with other pavement surface types (asphalt-based sealcoat, unsealed asphalt, concrete [median 9.0 μg/g, n = 12]). T-PAH in SHD from apartments with CT parking lots (median 129 μg/g) was 25 times higher than that in SHD from apartments with parking lots with other pavement surface types (median 5.1 μg/g). Presence or absence of CT on a parking lot explained 48% of the variance in log-transformed T-PAH in SHD. Urban land-use intensity near the residence also had a significant but weaker relation to T-PAH. No other variables tested, including carpeting, frequency of vacuuming, and indoor burning, were significant. PMID:20063893

Comparison of PAH Biodegradation and Desorption Kinetics During Bioremediation of Aged Petroleum Hydrocarbon Contaminated Soils

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huesemann, Michael H.; Hausmann, Tom S.; Fortman, Timothy J.

It is commonly assumed that mass-transfer limitations are the cause for slow and incomplete biodegradation of PAHs in aged soils. In order to test this hypothesis, the biodegradation rate and the abiotic release rate were measured and compared for selected PAHs in three different soils. It was found that PAH biodegradation was not mass-transfer limited during slurry bioremediation of an aged loamy soil. By contrast, PAH biodegradation rates were much larger than abiotic release rates in kaolinite clay indicating that sorbed-phase PAHs can apparently be biodegraded directly from mineral surfaces without prior desorption or dissolution into the aqueous phase. Amore » comparison of PAH biodegradation rates and abiotic release rates at termination of the slurry bioremediation treatment revealed that abiotic release rates are much larger than the respective biodegradation rates. In addition, it was found that the number of hydrocarbon degraders decreased by four orders of magnitude during the bioremediation treatment. It can therefore be concluded that the slow and incomplete biodegradation of PAHs is not caused by mass-transfer limitations but rather by microbial factors. Consequently, the residual PAHs that remain after extensive bioremediation treatment are still bioavailable and for that reason could pose a greater risk to environmental receptors than previously thought.« less

Coal-tar-based parking lot sealcoat: An unrecognized source of PAH to settled house dust

USGS Publications Warehouse

Mahler, B.J.; Van Metre, P.C.; Wilson, J.T.; Musgrove, M.; Burbank, T.L.; Ennis, T.E.; Bashara, T.J.

2010-01-01

Despite much speculation, the principal factors controlling concentrations of polycyclic aromatic hydrocarbons (PAH) in settled house dust (SHD) have not yet been identified. In response to recent reports that dust from pavement with coaltar-based sealcoat contains extremely high concentrations of PAH, we measured PAH in SHD from 23 apartments and in dust from their associated parking lots, one-half of which had coal-tar-based sealcoat (CT). The median concentration of total PAH (T-PAH) in dust from CT parking lots (4760 ??g/g, n = 11) was 530 times higher than that from parking lots with other pavement surface types (asphalt-based sealcoat, unsealed asphalt, concrete [median 9.0 ??g/g, n = 12]). T-PAH in SHD from apartments with CT parking lots (median 129 ??g/g) was 25 times higher than that in SHD from apartments with parking lots with other pavement surface types (median 5.1 ??g/g). Presence or absence of CT on a parking lot explained 48% of the variance in log-transformed T-PAH in SHD. Urban land-use intensity near the residence also had a significant but weaker relation to T-PAH. No other variables tested, including carpeting, frequency of vacuuming, and indoor burning, were significant. ?? 2010 American Chemical Society.

Analyses of polycyclic aromatic hydrocarbon (PAH) and chiral-PAH analogues-methyl-β-cyclodextrin guest-host inclusion complexes by fluorescence spectrophotometry and multivariate regression analysis.

PubMed

Greene, LaVana; Elzey, Brianda; Franklin, Mariah; Fakayode, Sayo O

2017-03-05

The negative health impact of polycyclic aromatic hydrocarbons (PAHs) and differences in pharmacological activity of enantiomers of chiral molecules in humans highlights the need for analysis of PAHs and their chiral analogue molecules in humans. Herein, the first use of cyclodextrin guest-host inclusion complexation, fluorescence spectrophotometry, and chemometric approach to PAH (anthracene) and chiral-PAH analogue derivatives (1-(9-anthryl)-2,2,2-triflouroethanol (TFE)) analyses are reported. The binding constants (K b ), stoichiometry (n), and thermodynamic properties (Gibbs free energy (ΔG), enthalpy (ΔH), and entropy (ΔS)) of anthracene and enantiomers of TFE-methyl-β-cyclodextrin (Me-β-CD) guest-host complexes were also determined. Chemometric partial-least-square (PLS) regression analysis of emission spectra data of Me-β-CD-guest-host inclusion complexes was used for the determination of anthracene and TFE enantiomer concentrations in Me-β-CD-guest-host inclusion complex samples. The values of calculated K b and negative ΔG suggest the thermodynamic favorability of anthracene-Me-β-CD and enantiomeric of TFE-Me-β-CD inclusion complexation reactions. However, anthracene-Me-β-CD and enantiomer TFE-Me-β-CD inclusion complexations showed notable differences in the binding affinity behaviors and thermodynamic properties. The PLS regression analysis resulted in square-correlation-coefficients of 0.997530 or better and a low LOD of 3.81×10 -7 M for anthracene and 3.48×10 -8 M for TFE enantiomers at physiological conditions. Most importantly, PLS regression accurately determined the anthracene and TFE enantiomer concentrations with an average low error of 2.31% for anthracene, 4.44% for R-TFE and 3.60% for S-TFE. The results of the study are highly significant because of its high sensitivity and accuracy for analysis of PAH and chiral PAH analogue derivatives without the need of an expensive chiral column, enantiomeric resolution, or use of a polarized

PAH phototoxicity: Identification of sensitive marine infaunal crustaceans and the effects of alkylation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boese, B.; Swartz, R.; Lamberson, J.

1995-12-31

The toxicity of some polycyclic aromatic hydrocarbons (PAHs) has been shown to be greatly enhanced in the presence of UV light. The objectives of the research were to: (1) test for PAH phototoxicity using seven marine infaunal crustacean species, (2) determine if the sensitivity to PAH phototoxicity was related to their potential exposure to sunlight in nature, and (3) determine if alkylation alters PAH phototoxicity. The first objective was accomplished by exposing test species to fluoranthene in 4-day, water-only bioassays. Survivors of the tests were then exposed to UV light in an exposure chamber for one hour. The differences betweenmore » EC50s (the ability to bury in sediment) before and after UV exposure were used to access phototoxicity. The results indicated that species having the greatest potential for natural exposure to sunlight were the least sensitive UV-enhanced fluoranthene toxicity. The amphipod, Rhepoxynius abronius, which in nature has the least potential for exposure to sunlight among the organisms tested, was the most sensitive. Rhepoxynius abronius was subsequently used in a series of tests to determine if alkylation of PAHs alters phototoxicity. This was done by conducting standard 10-day sediment bioassay using alkylated and unalkylated PAHs. As in the water-only tests, EC{sub 50}s were determined before and after UV light exposures. The results indicated that alkylation of PAHs, in general, did not alter phototoxicity.« less

Improved source apportionment of PAHs and Pb by integrating Pb stable isotopes and positive matrix factorization application (PAHs): A historical record case study from the northern South China Sea.

PubMed

Cai, Minggang; Lin, Yan; Chen, Meng; Yang, Weifeng; Du, Huihong; Xu, Ye; Cheng, Shayen; Xu, Fangjian; Hong, Jiajun; Chen, Mian; Ke, Hongwei

2017-12-31

To obtain the historical changes of pyrogenic sources, integrated source apportionment methods, which include PAH compositions, diagnostic ratios (DRs), Pb isotopic ratios, and positive matrix factorization (PMF) model, were developed and applied in sediments of the northern South China Sea. These methods provided a gradually clear picture of energy structural change. Spatially, Σ 15 PAH (11.3 to 95.5ng/g) and Pb (10.2 to 74.6μg/g) generally exhibited decreasing concentration gradient offshore; while the highest levels of PAHs and Pb were observed near the southern Taiwan Strait, which may be induced by accumulation of different fluvial input. Historical records of pollutants followed closely with the economic development of China, with fast growth of Σ 15 PAH and Pb occurring since the 1980s and 1990s, respectively. The phasing-out of leaded gasoline in China was captured with a sharp decrease of Pb after the mid-1990s. PAHs and Pb correlated well with TOC and clay content for core sediments, which was not observed for surface sediments. There was an up-core increase of high molecular PAH proportions. Coal and biomass burning were then qualitatively identified as the major sources of PAHs with DRs. Furthermore, shift toward less radiogenic signatures of Pb isotopic ratios after 1900 revealed the start and growing importance of industrial sources. Finally, a greater separation and quantification of various input was achieved by a three-factor PMF model, which made it clear that biomass burning, coal combustion, and vehicle emissions accounted for 40±20%, 41±13%, and 19±12% of PAHs through the core. Biomass and coal combustion acted as major sources before 2000, while contributions from vehicle emission soared thereafter. The integrated multi-methodologies here improved the source apportionment by reducing biases with a step-down and cross-validation perspective, which could be similarly applied to other aquatic systems. Copyright © 2017 Elsevier B.V. All

Polycyclic aromatic hydrocarbons (PAHs) associated with PM2.5 within boundary layer: Cloud/fog and regional transport.

PubMed

Yang, Minmin; Wang, Yan; Li, Hongli; Li, Tao; Nie, Xiaoling; Cao, Fangfang; Yang, Fengchun; Wang, Zhe; Wang, Tao; Qie, Guanghao; Jin, Tong; Du, Lili; Wang, Wenxing

2018-06-15

A study of PM 2.5 -associated PAHs analysis at Mount Lushan (1165m) was conducted to investigate the distributions of PAHs in PM 2.5 and influences of cloud/fog. The main purpose was to quantify the main emission sources of PAHs and estimate regional transport effects within the boundary layer. Mount Lushan is located between the boundary layer and troposphere, which is an ideal site for atmosphere transport investigation. The concentrations of PAHs in PM 2.5 were analyzed with GC-MS. The results showed that the volume concentration was 6.98ng/m 3 with a range from 1.47 to 25.17ng/m 3 and PAHs mass were 160.24μg/g (from 63.86 to 427.97μg/g) during the sampling time at Mount Lushan. The dominant compounds are BbF, Pyr and BP. In terms of aromatic-ring PAHs distributions, 4-6-ring PAHs are predominant, indicating that the high-ring PAHs tend to contribute more than low-ring PAHs in particulates. Due to frequent cloud/fog days at Mount Lushan, PAHs concentrations in the PM 2.5 were determined before and after cloud/fog weather. The results demonstrated that the cloud/fog and rain conditions cause lower PAHs levels. Regression analysis was used for studying the relationship of PAHs distributions with meteorological conditions like temperature, humidity and wind. The results showed that the temperature and wind speed were inversely related with PAHs concentration but humidity had no significant relationship. Furthermore, backward trajectories and PCA combined with DR (diagnostic ratio analysis) were employed to identify the influences of regional transport and main emission sources. The results revealed that PAHs in PM 2.5 were mainly affected by regional transport with the main emissions by mobile vehicle and steel industry, which contributed about 56.0% to the total PAHs in the area of Mount Lushan. In addition, backward trajectories revealed that the dominant air masses were from the northwest accounting for about one third of total PAHs. Copyright © 2018

Lung cancer risk from PAHs emitted from biomass combustion.

PubMed

Sarigiannis, Dimosthenis Α; Karakitsios, Spyros P; Zikopoulos, Dimitrios; Nikolaki, Spyridoula; Kermenidou, Marianthi

2015-02-01

This study deals with the assessment of the cancer risk attributable to PAH exposure, attributable to the increased use of biomass for space heating in Greece in the winter of 2012-2013. Three fractions of particulates (PM1, PM2.5 and PM10) were measured in two sampling sites (urban/residential and traffic-influenced) followed by chemical analysis of 19 PAHs and levoglucosan (used as a biomarker tracer). PAH-induced lung cancer risk was estimated by a comprehensive methodology that incorporated human respiratory tract deposition modelling in order to estimate the toxic equivalent concentration (TEQ) at each target tissue. This allowed us to further differentiate internal exposure and risk by age groups. Results showed that all PM fractions are higher in Greece during the cold months of the year, mainly due to biomass use for space heating. PAH and levoglucosan levels were highly correlated, indicating that particles emitted from biomass combustion are more toxic than PM emitted from other sources. The estimated lung cancer risk was non-negligible for residents close to the urban background monitoring site. Higher risk was estimated for infants and children, due to the higher bodyweight normalized dose and the human respiratory tract (HRT) physiology. HRT structure and physiology in youngsters favor deposition of particles that are smaller and more toxic per unit mass. In all cases, the estimated risk (5.7E-07 and 1.4E-06 for the urban background site and 1.4E-07 to 5.0E-07 for the traffic site) was lower to the one estimated by the conventional methodology (2.8E-06 and 9.7E-07 for the urban background and the traffic site respectively) that is based on Inhalation Unit Risk; the latter assumes that all PAHs adsorbed on particles are taken up by humans. With the methodology proposed herein, the estimated risk presents a 5-7 times difference between the two sampling sites (depending on the age group). These differences could not have been identified had we relied only

PAHs in Indian diet: Assessing the cancer risk.

PubMed

Singh, Lochan; Agarwal, Tripti

2018-07-01

Food products such as bread, biscuits, tea, coffee, oils, chocolates, grapes, pepper and fishes belonging to different categories represent a significant part of everyday diet in India and other countries having variable cooking techniques. In this study, we evaluated cancer risks of long term exposure to polycyclic aromatic hydrocarbons (PAHs) through consumption of these products for eight societal groups in India. Total concentrations of PAHs in these products from India ranged from 0.18 to 61967 μg kg -1 and the cancer risk values for the eight sections of Indian population ranged between 7.63E-10 to 5.05E+00, indicating product specific distribution of risk from non-significant to significant levels. Cereals, vegetables and decoctions contributed majorly to cancer risk and the most susceptible group identified was children. The spread of risk estimates followed Burr and Exponential distributions. To the best of our knowledge, this is the first study to develop information on the health risk faced by Indian population through dietary PAHs. Copyright © 2018 Elsevier Ltd. All rights reserved.

Characterization and source apportionment of PAHs from a highly urbanized river sediments based on land use analysis.

PubMed

Huang, Yanping; Liu, Min; Wang, Ruiqi; Khan, Saira Khalil; Gao, Dengzhou; Zhang, Yazhou

2017-10-01

The city-scale land use/land cover change derived by urbanization on the fates of PAHs is of great concerns recently. This study evaluated spatiotemporal variations and sources of PAHs from a highly urbanized river sediments in the Huangpu River, Shanghai. Results indicated that the concentrations of PAHs in the sediments varied greatly across locations and seasons. The concentration of Σ 16 PAHs in the dry season were 6 times higher than that in wet season. The mainstream and midstream of the Huangpu River were identified as the hotspots in both dry and wet seasons. However, 4-ring PAH compounds were dominated, contributing 42.41% ± 6.81% and 44.70 ± 7.73% in the dry and wet seasons, respectively. Multivariate statistical and land use analysis suggested that the main sources of PAHs derived from the cultivation, traffic and commercial activities. Buffer radii (<750 m) area with cultivated land, road/street and transportation and commercial and business facilities contributed significantly the PAHs in the sediment of the Huangpu River. Population density was also an important variable regulating the PAHs concentrations less than 750 m in the wet season. Risk assessment results revealed that the PAHs toxicity in the sediments was higher in dry season than in wet season. Overall, severe land use changes caused by rapid urbanization can contribute more amount of PAHs emission and complicated sources of PAHs, thus provide insights into the importance of land use types in indicating PAHs source. Copyright © 2017 Elsevier Ltd. All rights reserved.

Aerobic Bioremediation of PAH Contaminated Soil Results in Increased Genotoxicity and Developmental Toxicity.

PubMed

Chibwe, Leah; Geier, Mitra C; Nakamura, Jun; Tanguay, Robert L; Aitken, Michael D; Simonich, Staci L Massey

2015-12-01

The formation of more polar and toxic polycyclic aromatic hydrocarbon (PAH) transformation products is one of the concerns associated with the bioremediation of PAH-contaminated soils. Soil contaminated with coal tar (prebioremediation) from a former manufactured gas plant (MGP) site was treated in a laboratory scale bioreactor (postbioremediation) and extracted using pressurized liquid extraction. The soil extracts were fractionated, based on polarity, and analyzed for 88 PAHs (unsubstituted, oxygenated, nitrated, and heterocyclic PAHs). The PAH concentrations in the soil tested, postbioremediation, were lower than their regulatory maximum allowable concentrations (MACs), with the exception of the higher molecular weight PAHs (BaA, BkF, BbF, BaP, and IcdP), most of which did not undergo significant biodegradation. The soil extract fractions were tested for genotoxicity using the DT40 chicken lymphocyte bioassay and developmental toxicity using the embryonic zebrafish (Danio rerio) bioassay. A statistically significant increase in genotoxicity was measured in the unfractionated soil extract, as well as in four polar soil extract fractions, postbioremediation (p < 0.05). In addition, a statistically significant increase in developmental toxicity was measured in one polar soil extract fraction, postbioremediation (p < 0.05). A series of morphological abnormalities, including peculiar caudal fin malformations and hyperpigmentation in the tail, were measured in several soil extract fractions in embryonic zebrafish, both pre- and postbioremediation. The increased toxicity measured postbioremediation is not likely due to the 88 PAHs measured in this study (including quinones), because most were not present in the toxic polar fractions and/or because their concentrations did not increase postbioremediation. However, the increased toxicity measured postbioremediation is likely due to hydroxylated and carboxylated transformation products of the 3- and 4-ring PAHs (PHE, 1

Aerobic Bioremediation of PAH Contaminated Soil Results in Increased Genotoxicity and Developmental Toxicity

PubMed Central

Chibwe, Leah; Geier, Mitra C.; Nakamura, Jun; Tanguay, Robert L.; Aitken, Michael D.; Simonich, Staci L. Massey

2015-01-01

The formation of more polar and toxic polycyclic aromatic hydrocarbon (PAH) transformation products is one of the concerns associated with the bioremediation of PAH-contaminated soils. Soil contaminated with coal tar (pre-bioremediation) from a former manufactured gas plant (MGP) site was treated in a laboratory scale bioreactor (post-bioremediation) and extracted using pressurized liquid extraction. The soil extracts were fractionated, based on polarity, and analyzed for 88 PAHs (unsubstituted, oxygenated, nitrated, and heterocyclic PAHs). The PAH concentrations in the soil tested, post-bioremediation, were lower than their regulatory maximum allowable concentrations (MACs), with the exception of the higher molecular weight PAHs (BaA, BkF, BbF, BaP, and IcdP), most of which did not undergo significant biodegradation. The soil extract fractions were tested for genotoxicity using the DT40 chicken lymphocyte bioassay and developmental to xicity using the embryonic zebrafish (Danio rerio) bioassay. A statistically significant increase in genotoxicity was measured in the unfractionated soil extract, as well as in four polar soil extract fractions, post-bioremediation (p < 0.05). In addition, a statistically significant increase in developmental toxicity was measured in one polar soil extract fraction, post-bioremediation (p < 0.05). A series of morphological abnormalities, including peculiar caudal fin malformations and hyperpigmentation in the tail, were measured in several soil extract fractions in embryonic zebrafish, both pre- and post-bioremediation. The increased toxicity measured post-bioremediation is not likely due to the 88 PAHs measured in this study (including quinones), because most were not present in the toxic polar fractions and/or because their concentrations did not increase post-bioremediation. However, the increased toxicity measured post-bioremediation is likely due to hydroxylated and carboxylated transformation products of the 3- and 4-ring PAHs

Enhanced biodegradation of PAHs in historically contaminated soil by M. gilvum inoculated biochar.

PubMed

Xiong, Bijing; Zhang, Youchi; Hou, Yanwei; Arp, Hans Peter H; Reid, Brian J; Cai, Chao

2017-09-01

The inoculation of rice straw biochar with PAH-degrading Mycobacterium gilvum (1.27 × 10 11  ± 1.24 × 10 10  cell g -1 ), and the subsequent amendment of this composite material to PAHs contaminated (677 mg kg -1 ) coke plant soil, was conducted in order to investigate if would enhance PAHs biodegradation in soils. The microbe-biochar composite showed superior degradation capacity for phenanthrene, fluoranthene and pyrene. Phenanthrene loss in the microbe-biochar composite, free cell alone and biochar alone treatments was, respectively, 62.6 ± 3.2%, 47.3 ± 4.1% and non-significant (P > 0.05); whereas for fluoranthene loss it was 52.1 ± 2.3%; non-significant (P > 0.05) and non-significant (P > 0.05); and for pyrene loss it was 62.1 ± 0.9%; 19.7 ± 6.5% and 13.5 ± 2.8%. It was hypothesized that the improved remediation was underpinned by i) biochar enhanced mass transfer of PAHs from the soil to the carbonaceous biochar "sink", and ii) the subsequent degradation of the PAHs by the immobilized M. gilvum. To test this mechanism, a surfactant (Brij 30; 20 mg g -1 soil), was added to impede PAHs mass transfer to biochar and sorption. The surfactant increased solution phase PAH concentrations and significantly (P < 0.05) reduced PAH degradation in the biochar immobilized M. gilvum treatments; indicating the enhanced degradation occurred between the immobilized M. gilvum and biochar sorbed PAHs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Sedimentary records of polycyclic aromatic hydrocarbons (PAHs) in remote lakes across the Tibetan Plateau.

PubMed

Yang, Ruiqiang; Xie, Ting; Li, An; Yang, Handong; Turner, Simon; Wu, Guangjian; Jing, Chuanyong

2016-07-01

Sediment cores from five lakes across the Tibetan Plateau were used as natural archives to study the time trends of polycyclic aromatic hydrocarbons (PAHs). The depositional flux of PAHs generally showed an increasing trend from the deeper layers towards the upper layer sediments. The fluxes of PAHs were low with little variability before the 1950s, and then gradually increased to the late 1980s, with a faster increasing rate after the 1990s. This temporal pattern is clearly different compared with those remote lakes across the European mountains when PAHs started to decrease during the period 1960s-1980s. The difference of the temporal trend was attributed to differences in the economic development stages and energy structure between these regions. PAHs are dominated by the lighter 2&3-ring homologues with the averaged percentage over 87%, while it is notable that the percentage of heavier 4-6 ring PAHs generally increased in recent years, which suggests the contribution of local high-temperature combustion sources becoming more predominant. Copyright © 2016 Elsevier Ltd. All rights reserved.

Spatial distribution and temporal trends of polycyclic aromatic hydrocarbons (PAHs) in water and sediment from Songhua River, China.

PubMed

Zhao, Xuesong; Ding, Jing; You, Hong

2014-02-01

The spatial and temporal distributions of polycyclic aromatic hydrocarbons (PAHs) in the Songhua River, Harbin, China, were investigated. Seventy-seven samples, 42 water and 35 sediment samples, were collected in April and October of 2007 and January of 2008. The concentrations of total PAHs in water ranged from 163.54 to 2,746.25 ng/L with the average value of 934.62 ng/L, which were predominated by 2- and 3-ring PAHs. The concentrations of total 16 PAHs in sediment ranged from 68.25 to 654.15 ng/g dw with the average value of 234.15 ng/g dw, which were predominated by 4-, 5- and 6-ring PAHs. Statistical analysis of the PAH concentrations shown that the highest concentrations of the total PAHs were found during rainy season (October of 2007) and the lowest during snowy season (January of 2008). Ratios of specific PAH compounds, including fluoranthene/(fluoranthene + pyrene) (Flu/(Flu + Pyr)) and phenanthrene/(phenanthrene + anthracene) (An/(Ant + PhA)), were calculated to evaluate the possible sources of PAH contaminations. These ratios reflected pyrolytic inputs of PAHs in Songhua River water and a mixed pattern of pyrolytic and petrogenic inputs of PAHs in the Songhua River sediments. Ecotoxicological risk levels calculated for PAHs suggested that there were individual PAHs, which can less frequently cause biological impairment in some samples, but no samples had constituents that may frequently cause biological impairment. Total toxic benzo[a]pyrene equivalent of ΣcPAHs varied from 10.03 to 29.7 ng/g dw and from 0.36 to 1.92 ng/g dw for total toxic tetrachlorodibenzo-p-dioxin equivalent. The level of PAHs indicated a low toxicological risk to this area.

Genetic study of the PAH locus in the Iranian population: familial gene mutations and minihaplotypes.

PubMed

Razipour, Masoumeh; Alavinejad, Elaheh; Sajedi, Seyede Zahra; Talebi, Saeed; Entezam, Mona; Mohajer, Neda; Kazemi-Sefat, Golnaz-Ensieh; Gharesouran, Jalal; Setoodeh, Aria; Mohaddes Ardebili, Seyyed Mojtaba; Keramatipour, Mohammad

2017-10-01

Phenylketonuria (PKU), one of the most common inborn errors of amino acid metabolism, is caused by mutations in the phenylalanine hydroxylase (PAH) gene (PAH). PKU has wide allelic heterogeneity, and over 600 different disease-causing mutations in PAH have been detected to date. Up to now, there have been no reports on the minihaplotype (VNTR/STR) analysis of PAH locus in the Iranian population. The aims of the present study were to determine PAH mutations and minihaplotypes in Iranian families with PAH deficiency and to investigate the correlation between them. A total of 81 Iranian families with PAH deficiency were examined using PCR-sequencing of all 13 PAH exons and their flanking intron regions to identify sequence variations. Fragment analysis of the PAH minihaplotypes was performed by capillary electrophoresis for 59 families. In our study, 33 different mutations were found accounting for 95% of the total mutant alleles. The majority of these mutations (72%) were distributed across exons 7, 11, 2 and their flanking intronic regions. Mutation c.1066-11G > A was the most common with a frequency of 20.37%. The less frequent mutations, p.Arg261Gln (8%), p.Arg243Ter (7.4%), p.Leu48Ser (7.4%), p.Lys363Asnfs*37 (6.79%), c.969 + 5G > A (6.17%), p.Pro281Leu (5.56), c.168 + 5G > C (5.56), and p.Arg261Ter (4.94) together comprised about 52% of all mutant alleles. In this study, a total of seventeen PAH gene minihaplotypes were detected, six of which associated exclusively with particular mutations. Our findings indicate a broad PAH mutation spectrum in the Iranian population, which is consistent with previous studies reporting a wide range of PAH mutations, most likely due to ethnic heterogeneity. High prevalence of c.1066-11G > A mutation linked to minihaplotype 7/250 among both Iranian and Mediterranean populations is indicative of historical and geographical links between them. Also, strong association between particular mutations and minihaplotypes

Carbon in The Universe: PAHs and Clusters

NASA Technical Reports Server (NTRS)

Saykally, Richard J.

1997-01-01

Following the initial demonstration of this new technique (Science 265 1686 (1994)) and its application to a series of neutral PAHs which have been proposed as condidates for the UIRs (Nature 380, 227 (1996)), we have concentrated on two major aspects of this project. 1. Developing a detailed model for infrared emission spectra of a collection of highly excited PAH molecules, in which experimental bandshapes and temperature-dependent redshifts are used in conjunction with ab initio vibrational frequencies and intensities to simulate the UIR bands. This shows that a collection of nine different cations (as large as ovalene) reproduce the UIR features better than do a collection of the corresponding neutrals, but a detailed match with the UIRs is not obtained. 2. Construction of SPIRES apparatus for the study of PAH ion emission spectra. The design of this experiment is shown and described. Unfortunately a disasterous accident occurred just as we were preparing to start the testing of the ion apparatus. A vacuum implosion occurred, destroying the liquid He cooled monochromator. It has taken us nearly one full year to reconstruct this, and we arc only now in the final testing of the new system. We expect to try the ion experiments by the end of summer.

Systemic Exposure to PAHs and Benzene in Firefighters Suppressing Controlled Structure Fires

PubMed Central

Fent, Kenneth W.; Eisenberg, Judith; Snawder, John; Sammons, Deborah; Pleil, Joachim D.; Stiegel, Matthew A.; Mueller, Charles; Horn, Gavin P.; Dalton, James

2014-01-01

Turnout gear provides protection against dermal exposure to contaminants during firefighting; however, the level of protection is unknown. We explored the dermal contribution to the systemic dose of polycyclic aromatic hydrocarbons (PAHs) and other aromatic hydrocarbons in firefighters during suppression and overhaul of controlled structure burns. The study was organized into two rounds, three controlled burns per round, and five firefighters per burn. The firefighters wore new or laundered turnout gear tested before each burn to ensure lack of PAH contamination. To ensure that any increase in systemic PAH levels after the burn was the result of dermal rather than inhalation exposure, the firefighters did not remove their self-contained breathing apparatus until overhaul was completed and they were >30 m upwind from the burn structure. Specimens were collected before and at intervals after the burn for biomarker analysis. Urine was analyzed for phenanthrene equivalents using enzyme-linked immunosorbent assay and a benzene metabolite (s-phenylmercapturic acid) using liquid chromatography/tandem mass spectrometry; both were adjusted by creatinine. Exhaled breath collected on thermal desorption tubes was analyzed for PAHs and other aromatic hydrocarbons using gas chromatography/mass spectrometry. We collected personal air samples during the burn and skin wipe samples (corn oil medium) on several body sites before and after the burn. The air and wipe samples were analyzed for PAHs using a liquid chromatography with photodiode array detection. We explored possible changes in external exposures or biomarkers over time and the relationships between these variables using non-parametric sign tests and Spearman tests, respectively. We found significantly elevated (P < 0.05) post-exposure breath concentrations of benzene compared with pre-exposure concentrations for both rounds. We also found significantly elevated post-exposure levels of PAHs on the neck compared with pre

Polycyclic Aromatic Hydrocarbons (PAHs) in inland aquatic ecosystems: Perils and remedies through biosensors and bioremediation.

PubMed

Behera, Bijay Kumar; Das, Abhishek; Sarkar, Dhruba Jyoti; Weerathunge, Pabudi; Parida, Pranaya Kumar; Das, Basanta Kumar; Thavamani, Palanisami; Ramanathan, Rajesh; Bansal, Vipul

2018-05-25

Polycyclic Aromatic Hydrocarbons (PAHs) are among the most ubiquitous environmental pollutants of high global concern. PAHs belong to a diverse family of hydrocarbons with over one hundred compounds known, each containing at least two aromatic rings in their structure. Due to hydrophobic nature, PAHs tend to accumulate in the aquatic sediments, leading to bioaccumulation and elevated concentrations over time. In addition to their well-manifested mutagenic and carcinogenic effects in humans, they pose severe detrimental effects to aquatic life. The high eco-toxicity of PAHs has attracted a number of reviews, each dealing specifically with individual aspects of this global pollutant. However, efficient management of PAHs warrants a holistic approach that combines a thorough understanding of their physico-chemical properties, modes of environmental distribution and bioaccumulation, efficient detection, and bioremediation strategies. Currently, there is a lack of a comprehensive study that amalgamates all these aspects together. The current review, for the first time, overcomes this constraint, through providing a high level comprehensive understanding of the complexities faced during PAH management, while also recommending future directions through potentially viable solutions. Importantly, effective management of PAHs strongly relies upon reliable detection tools, which are currently non-existent, or at the very best inefficient, and therefore have a strong prospect of future development. Notably, the currently available biosensor technologies for PAH monitoring have not so far been compiled together, and therefore a significant focus of this article is on biosensor technologies that are critical for timely detection and efficient management of PAHs. This review is focussed on inland aquatic ecosystems with an emphasis on fish biodiversity, as fish remains a major source of food and livelihood for a large proportion of the global population. This thought provoking

Construction of PAH-degrading mixed microbial consortia by induced selection in soil.

PubMed

Zafra, German; Absalón, Ángel E; Anducho-Reyes, Miguel Ángel; Fernandez, Francisco J; Cortés-Espinosa, Diana V

2017-04-01

Bioremediation of polycyclic aromatic hydrocarbons (PAHs)-contaminated soils through the biostimulation and bioaugmentation processes can be a strategy for the clean-up of oil spills and environmental accidents. In this work, an induced microbial selection method using PAH-polluted soils was successfully used to construct two microbial consortia exhibiting high degradation levels of low and high molecular weight PAHs. Six fungal and seven bacterial native strains were used to construct mixed consortia with the ability to tolerate high amounts of phenanthrene (Phe), pyrene (Pyr) and benzo(a)pyrene (BaP) and utilize these compounds as a sole carbon source. In addition, we used two engineered PAH-degrading fungal strains producing heterologous ligninolytic enzymes. After a previous selection using microbial antagonism tests, the selection was performed in microcosm systems and monitored using PCR-DGGE, CO 2 evolution and PAH quantitation. The resulting consortia (i.e., C1 and C2) were able to degrade up to 92% of Phe, 64% of Pyr and 65% of BaP out of 1000 mg kg -1 of a mixture of Phe, Pyr and BaP (1:1:1) after a two-week incubation. The results indicate that constructed microbial consortia have high potential for soil bioremediation by bioaugmentation and biostimulation and may be effective for the treatment of sites polluted with PAHs due to their elevated tolerance to aromatic compounds, their capacity to utilize them as energy source. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of pyrolysis temperatures on freely dissolved polycyclic aromatic hydrocarbon (PAH) concentrations in sewage sludge-derived biochars.

PubMed

Zielińska, Anna; Oleszczuk, Patryk

2016-06-01

The aim of this study was to evaluate the effect of sewage sludge pyrolysis on freely dissolved (Cfree) polycyclic aromatic hydrocarbon (PAH) contents in biochars. Four sewage sludges with varying properties and PAH contents were pyrolysed at temperatures of 500 °C, 600 °C or 700 °C. Cfree PAH contents were determined using polyoxymethylene (POM). The contents of Cfree PAHs in the sludges ranged from 262 to 294 ng L(-1). Sewage sludge-derived biochars have from 2.3- to 3.4-times lower Cfree PAH contents comparing to corresponding sewage sludges. The Cfree PAH contents in the biochars ranged between 81 ng L(-1) and 126 ng L(-1). As regards agricultural use of biochar, the lower contents of Cfree PAHs in the biochars compared to the sewage sludges makes biochar a safer material than sewage sludge in terms of PAH contents. Copyright © 2016 Elsevier Ltd. All rights reserved.

Desorption and Bioavailability of PAHs in Contaminated Soil Subjected to Long-Term In Situ Biostimulation

PubMed Central

Richardson, Stephen D.; Aitken, Michael D.

2011-01-01

The distribution and potential bioavailability of polycyclic aromatic hydrocarbons (PAHs) in soil from a former manufactured-gas plant (MGP) site were examined before and after long-term biostimulation under simulated in situ conditions. Treated soil was collected from the oxygenated zones of two continuous-flow columns, one subjected to biostimulation and the other serving as a control, and separated into low- and high-density fractions. In the original soil, over 50% of the total PAH mass was associated with lower-density particles, which comprised < 2% of the total soil mass. However, desorbable fractions of PAHs were much lower in the low-density material than in the high-density material. After over 500 d of biostimulation, significant removal of total PAHs occurred in both the high- and low-density materials (77% and 53%, respectively), with three- and four-ring PAHs accounting for the majority of the observed mass loss. Total PAHs that desorbed over a 28-d period were substantially lower in treated soil from the biostimulated column than in the original soil for both the high-density material (23 versus 63%) and low-density material (5 versus 20%). The fast-desorbing fractions quantified by a two-site desorption model ranged from 0.1 to 0.5 for most PAHs in the original soil but were essentially zero in the biostimulated soil. The fast-desorbing fractions in the original soil underestimated the extent of PAH biodegradation observed in the biostimulated column, and thus was not a good predictor of PAH bioavailability after long-term, simulated in situ biostimulation. PMID:21932296

Sources of sedimentary PAHs in tropical Asian waters: differentiation between pyrogenic and petrogenic sources by alkyl homolog abundance.

PubMed

Saha, Mahua; Togo, Ayako; Mizukawa, Kaoruko; Murakami, Michio; Takada, Hideshige; Zakaria, Mohamad P; Chiem, Nguyen H; Tuyen, Bui Cach; Prudente, Maricar; Boonyatumanond, Ruchaya; Sarkar, Santosh Kumar; Bhattacharya, Badal; Mishra, Pravakar; Tana, Touch Seang

2009-02-01

We collected surface sediment samples from 174 locations in India, Indonesia, Malaysia, Thailand, Vietnam, Cambodia, Laos, and the Philippines and analyzed them for polycyclic aromatic hydrocarbons (PAHs) and hopanes. PAHs were widely distributed in the sediments, with comparatively higher concentrations in urban areas (Sigma PAHs: approximately 1000 to approximately 100,000 ng/g-dry) than in rural areas ( approximately 10 to approximately 100g-dry), indicating large sources of PAHs in urban areas. To distinguish petrogenic and pyrogenic sources of PAHs, we calculated the ratios of alkyl PAHs to parent PAHs: methylphenanthrenes to phenanthrene (MP/P), methylpyrenes+methylfluoranthenes to pyrene+fluoranthene (MPy/Py), and methylchrysenes+methylbenz[a]anthracenes to chrysene+benz[a]anthracene (MC/C). Analysis of source materials (crude oil, automobile exhaust, and coal and wood combustion products) gave thresholds of MP/P=0.4, MPy/Py=0.5, and MC/C=1.0 for exclusive combustion origin. All the combustion product samples had the ratios of alkyl PAHs to parent PAHs below these threshold values. Contributions of petrogenic and pyrogenic sources to the sedimentary PAHs were uneven among the homologs: the phenanthrene series had a greater petrogenic contribution, whereas the chrysene series had a greater pyrogenic contribution. All the Indian sediments showed a strong pyrogenic signature with MP/P approximately 0.5, MPy/Py approximately 0.1, and MC/C approximately 0.2, together with depletion of hopanes indicating intensive inputs of combustion products of coal and/or wood, probably due to the heavy dependence on these fuels as sources of energy. In contrast, sedimentary PAHs from all other tropical Asian cities were abundant in alkylated PAHs with MP/P approximately 1-4, MPy/Py approximately 0.3-1, and MC/C approximately 0.2-1.0, suggesting a ubiquitous input of petrogenic PAHs. Petrogenic contributions to PAH homologs varied among the countries: largest in Malaysia

Diffusive flux of PAHs across sediment-water and water-air interfaces at urban superfund sites.

PubMed

Minick, D James; Anderson, Kim A

2017-09-01

Superfund sites may be a source of polycyclic aromatic hydrocarbons (PAHs) to the surrounding environment. These sites can also act as PAH sinks from present-day anthropogenic activities, especially in urban locations. Understanding PAH transport across environmental compartments helps to define the relative contributions of these sources and is therefore important for informing remedial and management decisions. In the present study, paired passive samplers were co-deployed at sediment-water and water-air interfaces within the Portland Harbor Superfund Site and the McCormick and Baxter Superfund Site. These sites, located along the Willamette River (Portland, OR, USA), have PAH contamination from both legacy and modern sources. Diffusive flux calculations indicate that the Willamette River acts predominantly as a sink for low molecular weight PAHs from both the sediment and the air. The sediment was also predominantly a source of 4- and 5-ring PAHs to the river, and the river was a source of these same PAHs to the air, indicating that legacy pollution may be contributing to PAH exposure for residents of the Portland urban center. At the remediated McCormick and Baxter Superfund Site, flux measurements highlight locations within the sand and rock sediment cap where contaminant breakthrough is occurring. Environ Toxicol Chem 2017;36:2281-2289. © 2017 SETAC. © 2017 SETAC.

PAH chemistry at eV internal energies. 1. H-shifted isomers

NASA Astrophysics Data System (ADS)

Trinquier, Georges; Simon, Aude; Rapacioli, Mathias; Gadéa, Florent Xavier

2017-06-01

The PAH family of organic compounds (polycyclic aromatic hydrocarbons), involved in several fields of chemistry, has received particular attention in astrochemistry, where their vibrational spectroscopy, thermodynamics, dynamics, and fragmentation properties are now abundantly documented. This survey aims at drawing trends for low spin-multiplicity surfaces of PAHs bearing internal energies in the range 1-10 eV. It addresses some typical alternatives to the ground-state regular structures of PAHs, making explicit possible intramolecular rearrangements leading to high-lying minima. These isomerisations should be taken into consideration when addressing PAH processing in astrophysical conditions. The first part of this double-entry study focuses on the hydrogen-shifted forms, which bear both a carbene center and a saturated carbon. It rests upon DFT calculations mainly performed on two emblematic PAH representatives, coronene and pyrene, in their neutral and mono- and multi-cationic states. Systematically searched for in neutral species, these H-shifted minima are lying 4-5 eV above the regular all-conjugated forms, and are separated by barriers of about 1 eV. General hydrogen-shifting is found to be easier for cationic species as the relative energies of their H-shifted minima are 1-1.5 eV lower than those for neutral species. As much as possible, classical knowledge and concepts of organic chemistry such as aromaticity and Clar's rules are invoked for result interpretation.

Levels and patterns of polycyclic aromatic hydrocarbons (PAHs) in soils after forest fires in South Korea.

PubMed

Kim, Eun Jung; Choi, Sung-Deuk; Chang, Yoon-Seok

2011-11-01

To investigate the influence of biomass burning on the levels of polycyclic aromatic hydrocarbons (PAHs) in soils, temporal trends and profiles of 16 US Environmental Protection Agency priority PAHs were studied in soil and ash samples collected 1, 5, and 9 months after forest fires in South Korea. The levels of PAHs in the burnt soils 1 month after the forest fires (mean, 1,200 ng/g dry weight) were comparable with those of contaminated urban soils. However, 5 and 9 months after the forest fires, these levels decreased considerably to those of general forest soils (206 and 302 ng/g, respectively). The burnt soils and ash were characterized by higher levels of light PAHs with two to four rings, reflecting direct emissions from biomass burning. Five and 9 months after the forest fires, the presence of naphthalene decreased considerably, which indicates that light PAHs were rapidly volatilized or degraded from the burnt soils. The temporal trend and pattern of PAHs clearly suggests that soils in the forest-fire region can be contaminated by PAHs directly emitted from biomass burning. However, the fire-affected soils can return to the pre-fire conditions over time through the washout and wind dissipation of the ash with high content of PAHs as well as vaporization or degradation of light PAHs.

Polycyclic aromatic hydrocarbons (PAHs) in atmospheric PM2.5 around 2013 Asian Youth Games period in Nanjing

NASA Astrophysics Data System (ADS)

Li, Xuxu; Kong, Shaofei; Yin, Yan; Li, Li; Yuan, Liang; Li, Qi; Xiao, Hui; Chen, Kui

2016-06-01

Eighteen polycyclic aromatic hydrocarbons (PAHs) in PM2.5 collected near the Nanjing Olympic Sports Center across the Asian Youth Games (AYG) period (from August 2 to August 28, 2013) were analyzed using GC-MS. Their levels, sources and health risks to human were discussed. Results showed that the total concentrations of PAHs in PM2.5 were 9.43, 7.21 and 8.83 ng m- 3 for pre- (August 3-15), during- (August 16-24) and post- (August 25-28) AYG periods, respectively. They were dominated by 5-ring and 6-ring PAHs. Total PAHs concentrations in PM2.5 during AYG period decreased by 24%, when compared with those for pre-AYG period. For combustion-derived PAHs and carcinogenic PAHs, they decreased by 26% and 21%, respectively. It implied that the pollution control measures implemented during the AYG can effectively reduce the emission of PAHs from various sources. The poor correlations between PAHs and meteorological parameters also favored that the variations of PAHs were raised by the changes of emission sources. Diagnostic ratios and principal component analysis revealed that vehicle emission and coal combustion were the predominant contributors, with minimal effects from biomass burning and petroleum. The health risks for human exposed to PAHs in PM2.5 were quantitatively assessed by BaP equivalent concentration (BaPeq) and the incremental lifetime cancer risk (ILCR). The estimated ILCR value of PAHs during the AYG periods decreased by 23% and 27% for children and adults when compared with those for the pre-AYG, respectively. It indicated that the pollution control measures reduced the risks of PAHs to sportsmen or human gathered around the Olympic Sport Center.

Characterization of a Microbial Consortium for the Bioremoval of Polycyclic Aromatic Hydrocarbons (PAHs) in Water

PubMed Central

Blanco-Enríquez, Esmeralda G.; Zavala-Díaz de la Serna, Francisco Javier; Peralta-Pérez, María del Rosario; Ballinas-Casarrubias, Lourdes; Salmerón, Iván; Rubio-Arias, Héctor; Rocha-Gutiérrez, Beatriz A.

2018-01-01

Pollution of freshwater ecosystems from polycyclic aromatic hydrocarbons (PAHs) is a global concern. The US Environmental Protection Agency (EPA) has included the PAHs pyrene, phenanthrene, and naphthalene among the 16 priority compounds of special concern for their toxicological effects. The aim of this study was to adapt and characterize a microbial consortium from ore waste with the potential to remove these three PAHs from water. This microbial consortium was exposed to the target PAHs at levels of 5, 10, 20, 50, and 100 mg L−1 for 14 days. PAH bioremoval was measured using the analytical technique of solid phase microextraction, followed by gas chromatography mass spectrometry (SPME-GC/MS). The results revealed that up to 90% of the target PAHs can be removed from water after 14 days at a concentration level of 100 mg L−1. The predominant group of microorganisms identified at the phylum taxonomic level were the Proteobacteria, while the Actinobacteria were the predominant subgroup. The removal of phenanthrene, naphthalene, and pyrene predominantly occurred in specimens of genera Stenotrophomonas, Williamsia, and Chitinophagaceae, respectively. This study demonstrates that the use of specific microorganisms is an alternative method of reducing PAH levels in water. PMID:29757264

Association of plasma IL-6 and Hsp70 with HRV at different levels of PAHs metabolites.

PubMed

Ye, Jian; Zhu, Rui; He, Xiaosheng; Feng, Yingying; Yang, Liangle; Zhu, Xiaoyan; Deng, Qifei; Wu, Tangchun; Zhang, Xiaomin

2014-01-01

Exposure to polycyclic aromatic hydrocarbons (PAHs) is associated with reduced heart rate variability (HRV), a strong predictor of cardiovascular diseases, but the mechanism is not well understood. We hypothesized that PAHs might induce systemic inflammation and stress response, contributing to altered cardiac autonomic function. HRV indices were measured using a 3-channel digital Holter monitor in 800 coke oven workers. Plasma levels of interleukin-6 (IL-6) and heat shock protein 70 (Hsp70) were determined using ELISA. Twelve urinary PAHs metabolites (OH-PAHs) were measured by gas chromatography-mass spectrometry. We found that significant dose-dependent relationships between four urinary OH-PAHs and IL-6 (all Ptrend<0.05); and an increase in quartiles of IL-6 was significantly associated with a decrease in total power (TP) and low frequency (LF) (Ptrend = 0.014 and 0.006, respectively). In particular, elevated IL-6 was associated in a dose-dependent manner with decreased TP and LF in the high-PAHs metabolites groups (all Ptrend<0.05), but not in the low-PAHs metabolites groups. No significant association between Hsp70 and HRV in total population was found after multivariate adjustment. However, increased Hsp70 was significantly associated with elevated standard deviation of NN intervals (SDNN), TP and LF in the low-PAHs metabolites groups (all Ptrend<0.05). We also observed that both IL-6 and Hsp70 significantly interacted with multiple PAHs metabolites in relation to HRV. In coke oven workers, increased IL-6 was associated with a dose-response decreased HRV in the high-PAHs metabolites groups, whereas increase of Hsp70 can result in significant dose-related increase in HRV in the low-PAHs metabolites groups.

Association of Plasma IL-6 and Hsp70 with HRV at Different Levels of PAHs Metabolites

PubMed Central

He, Xiaosheng; Feng, Yingying; Yang, Liangle; Zhu, Xiaoyan; Deng, Qifei; Wu, Tangchun; Zhang, Xiaomin

2014-01-01

Background Exposure to polycyclic aromatic hydrocarbons (PAHs) is associated with reduced heart rate variability (HRV), a strong predictor of cardiovascular diseases, but the mechanism is not well understood. Objectives We hypothesized that PAHs might induce systemic inflammation and stress response, contributing to altered cardiac autonomic function. Methods HRV indices were measured using a 3-channel digital Holter monitor in 800 coke oven workers. Plasma levels of interleukin-6 (IL-6) and heat shock protein 70 (Hsp70) were determined using ELISA. Twelve urinary PAHs metabolites (OH-PAHs) were measured by gas chromatography-mass spectrometry. Results We found that significant dose-dependent relationships between four urinary OH-PAHs and IL-6 (all P trend<0.05); and an increase in quartiles of IL-6 was significantly associated with a decrease in total power (TP) and low frequency (LF) (P trend = 0.014 and 0.006, respectively). In particular, elevated IL-6 was associated in a dose-dependent manner with decreased TP and LF in the high-PAHs metabolites groups (all P trend<0.05), but not in the low-PAHs metabolites groups. No significant association between Hsp70 and HRV in total population was found after multivariate adjustment. However, increased Hsp70 was significantly associated with elevated standard deviation of NN intervals (SDNN), TP and LF in the low-PAHs metabolites groups (all P trend<0.05). We also observed that both IL-6 and Hsp70 significantly interacted with multiple PAHs metabolites in relation to HRV. Conclusions In coke oven workers, increased IL-6 was associated with a dose-response decreased HRV in the high-PAHs metabolites groups, whereas increase of Hsp70 can result in significant dose-related increase in HRV in the low-PAHs metabolites groups. PMID:24722336

Long-term assessment of natural attenuation: statistical approach on soils with aged PAH contamination.

PubMed

Ouvrard, Stéphanie; Chenot, Elodie-Denise; Masfaraud, Jean-François; Schwartz, Christophe

2013-07-01

Natural attenuation processes valorization for PAH-contaminated soil remediation has gained increasing interest from site owners. A misunderstanding of this method and a small amount of data available does not encourage its development. However, monitored natural attenuation (MNA) offers a valuable, cheaper and environmentally friendly alternative to more classical options such as physico-chemical treatments (e.g., chemical oxidation, thermal desorption). The present work proposes the results obtained during a long-term natural attenuation assessment of historically contaminated industrial soils under real climatic conditions. This study was performed after a 10 year natural attenuation period on 60 off-ground lysimeters filled with contaminated soils from different former industrial sites (coking industry, manufactured gas plants) whose initial concentration of PAH varied between 380 and 2,077 mg kg(-1). The analysed parameters included leached water characterization, soil PAH concentrations, evaluation of vegetation cover quality and quantity. Results showed a good efficiency of the PAH dissipation and limited transfer of contaminants to the environment. It also highlighted the importance of the fine soil fractions in controlling PAH reactivity. PAH dissipation through water leaching was limited and did not present a significant risk for the environment. This PAH water concentration appeared however as a good indicator of overall dissipation rate, thereby illustrating the importance of pollutant availability in predicting its degradation potential.

Detoxification of polycyclic aromatic hydrocarbons (PAHs) in Arabidopsis thaliana involves a putative flavonol synthase.

PubMed

Hernández-Vega, Juan C; Cady, Brian; Kayanja, Gilbert; Mauriello, Anthony; Cervantes, Natalie; Gillespie, Andrea; Lavia, Lisa; Trujillo, Joshua; Alkio, Merianne; Colón-Carmona, Adán

2017-01-05

Polycyclic aromatic hydrocarbons (PAHs) are environmental contaminants with cytotoxic, teratogenic and carcinogenic properties. Bioremediation studies with bacteria have led to the identification of dioxygenases (DOXs) in the first step to degrade these recalcitrant compounds. In this study, we characterized the role of the Arabidopsis thaliana AT5G05600, a putative DOX of the flavonol synthase family, in the transformation of PAHs. Phenotypic analysis of loss-of-function mutant lines showed that these plant lines were less sensitive to the toxic effects of phenanthrene, suggesting possible roles of this gene in PAH degradation in vivo. Interestingly, these mutant lines showed less accumulation of H 2 O 2 after PAH exposure. Transgenic lines over-expressing At5g05600 showed a hypersensitive response and more oxidative stress after phenanthrene treatments. Moreover, fluorescence spectra results of biochemical assays with the recombinant His-tagged protein AT5G05600 detected chemical modifications of phenanthrene. Taken together, these results support the hypothesis that AT5G05600 is involved in the catabolism of PAHs and the accumulation of toxic intermediates during PAH biotransformation in plants. This research represents the first step in the design of transgenic plants with the potential to degrade PAHs, leading to the development of vigorous plant varieties that can reduce the levels of these pollutants in the environment. Copyright © 2016 Elsevier B.V. All rights reserved.

MANAGEMENT OF PAH-IMPACTED SITES VIA IN SITU CHEMICAL CONTAINMENT AND MONITORING

EPA Science Inventory

On a world-wide basis the magnitude of environmental contamination problems involving polycyclic aromatic hydrocarbon (PAHs) is unmatched by any other group of organic chemicals. Despite the recognized limitations to PAH biodegradation (e.g., intrinsic chemical stability of the h...

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

NASA Technical Reports Server (NTRS)

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

2013-01-01

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

Immobilization of fungal laccase onto a nonionic surfactant-modified clay material: application to PAH degradation.

PubMed

Chang, Yi-Tang; Lee, Jiunn-Fwu; Liu, Keng-Hua; Liao, Yi-Fen; Yang, Vivian

2016-03-01

Nonionic surfactant-modified clay is a useful absorbent material that effectively removes hydrophobic organic compounds from soil/groundwater. We developed a novel material by applying an immobilized fungal laccase onto nonionic surfactant-modified clay. Low-water-solubility polycyclic aromatic hydrocarbons (PAHs) (naphthalene/phenanthrene) were degraded in the presence of this bioactive material. PAH degradation by free laccase was higher than degradation by immobilized laccase when the surfactant concentration was allowed to form micelles. PAH degradation by immobilized laccase on TX-100-modified clay was higher than on Brij35-modified clay. Strong laccase degradation of PAH can be maintained by adding surfactant monomers or micelles. The physical adsorption of nonionic surfactants onto clay plays an important role in PAH degradation by laccase, which can be explained by the structure and molecular interactions of the surfactant with the clay and enzyme. A system where laccase is immobilized onto TX-100-monomer-modified clay is a good candidate bioactive material for in situ PAHs bioremediation.

PAHs behavior in surface water and groundwater of the Yellow River estuary: Evidence from isotopes and hydrochemistry.

PubMed

Li, Jing; Li, Fadong; Liu, Qiang

2017-07-01

Large-scale irrigation projects have impacted the regional surface-groundwater interactions in the North China Plain (NCP). Given this concern, the aim of this study is to evaluate levels of PAH pollution, identify the sources of the PAHs, analyze the influence of surface-groundwater interactions on PAH distribution, and propose urgent management strategies for PAHs in China's agricultural areas. PAH concentrations, hydrochemical indicators and stable isotopic compositions (δ 18 O and δ 2 H) were determined for surface water (SW) and groundwater (GW) samples. PAHs concentrations in surface water and groundwater varied from 11.84 to 393.12 ng/L and 8.51-402.84 ng/L, respectively, indicating mild pollution. The seasonal variations showed the following trend: PAHs in surface water at the low-water phase > PAHs in groundwater at the low-water phase > PAHs in surface water at the high-water phase > PAHs in groundwater at the high-water phase. Hydrochemical and δ 18 O value of most groundwater samples distributed between the Yellow River and seawater. The mean value of mixture ratio of the Yellow River water recharge to the groundwater was 65%, few anomalous sites can reach to 90%. Surface-groundwater interactions influence the spatial distribution of PAHs in the study area. In light of the ongoing serious pollution, management practices for source control, improved control technologies, and the construction of a monitoring network to warn of increased risk are urgently needed. Copyright © 2017 Elsevier Ltd. All rights reserved.

PAH distribution and mass fluxes in the Three Gorges Reservoir after impoundment of the Three Gorges Dam.

PubMed

Deyerling, Dominik; Wang, Jingxian; Hu, Wei; Westrich, Bernhard; Peng, Chengrong; Bi, Yonghong; Henkelmann, Bernhard; Schramm, Karl-Werner

2014-09-01

Mass fluxes of polycyclic aromatic hydrocarbons (PAHs) were calculated for the Three Gorges Reservoir (TGR) in China, based on concentration and discharge data from the Yangtze River. Virtual Organisms (VOs) have been applied during four campaigns in 2008, 2009 (twice) and 2011 at sampling sites distributed from Chongqing to Maoping. The total PAH mass fluxes ranged from 110 to 2,160 mg s(-1). Highest loads were determined at Chongqing with a decreasing trend towards Maoping in all four sampling campaigns. PAH remediation capacity of the TGR was found to be high as the mass flux reduced by more than half from upstream to downstream. Responsible processes are thought to be adsorption of PAH to suspended particles, dilution and degradation. Furthermore, the dependence of PAH concentration upon water depth was investigated at Maoping in front of the Three Gorges Dam. Although considerable differences could be revealed, there was no trend observable. Sampling of water with self-packed filter cartridges confirmed more homogenous PAH depth distribution. Moreover, PAH content of suspended particles was estimated from water concentrations gathered by VOs based on a water-particle separation model and subsequently compared to PAH concentration measured in water and in filter cartridges. It could be shown that the modeled data predicts the concentration caused by particle-bound PAHs to be about 6 times lower than PAHs dissolved in water. Besides, the model estimates the proportions of 5- and 6-ring PAHs being higher than in water phase. Copyright © 2014 Elsevier B.V. All rights reserved.

In-situ Phytoremediation of PAH and PCB Contaminated Marine Sediments with Eelgrass (Zostera marina)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huesemann, Michael H.; Hausmann, Tom S.; Fortman, Timothy J.

In view of the fact that there are presently no cost-effective in-situ treatment technologies for contaminated sediments, a 60 week long phytoremediation feasibility study was conducted in seawater-supplied outdoor ponds to determine whether eelgrass (Zostera marina) is capable of removing polynuclear aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) from submerged marine sediments. It was determined that all PAHs and PCBs, independent of the number of aromatic rings and degree of chlorination, respectively, were removed to a much larger extent in planted sediments compared to unplanted controls. After 60 weeks of treatment, the concentration of total PAHs decreased by 73% inmore » planted sediments but only 25% in unplanted controls. Similarly, total PCBs declined by 60% in the presence of plants while none were removed in the unplanted sediment. Overall, PAH and PCB biodegradation was greatest in the sediment layer that contained most of the eelgrass roots. Abiotic desorption tests conducted at week 32 confirmed that the phytoremediation process was not controlled by mass-transfer or bioavailability limitations since all PAHs and PCBs desorbed rapidly and to a large extent from the sediment. PAHs were detected in both roots and shoots, with root and shoot bioaccumulation factors for total PAHs amounting to approximately 3 and 1, respectively, after 60 weeks of phytoremediation treatment. Similarly, the root bioccumulation factor for total PCBs was around 4, while no PCBs were detected in the eelgrass leaves at the end of the experiment. The total mass fraction of PAHs and PCBs absorbed and translocated by plant biomass during the 60 week period was insignificant, amounting to less than 0.5% of the total mass of PAHs and PCBs which was initially present in the sediment. Finally, the number of total heterotrophic bacteria and hydrocarbon degraders was slightly but not statistically significantly greater in planted sediments than in unplanted

Altered Lipid Synthesis by Lack of Yeast Pah1 Phosphatidate Phosphatase Reduces Chronological Life Span*

PubMed Central

Park, Yeonhee; Han, Gil-Soo; Mileykovskaya, Eugenia; Garrett, Teresa A.; Carman, George M.

2015-01-01

In Saccharomyces cerevisiae, Pah1 phosphatidate phosphatase, which catalyzes the dephosphorylation of phosphatidate to yield diacylglycerol, plays a crucial role in the synthesis of the storage lipid triacylglycerol. This evolutionarily conserved enzyme also plays a negative regulatory role in controlling de novo membrane phospholipid synthesis through its consumption of phosphatidate. We found that the pah1Δ mutant was defective in the utilization of non-fermentable carbon sources but not in oxidative phosphorylation; the mutant did not exhibit major changes in oxygen consumption rate, mitochondrial membrane potential, F1F0-ATP synthase activity, or gross mitochondrial morphology. The pah1Δ mutant contained an almost normal complement of major mitochondrial phospholipids with some alterations in molecular species. Although oxidative phosphorylation was not compromised in the pah1Δ mutant, the cellular levels of ATP in quiescent cells were reduced by 2-fold, inversely correlating with a 4-fold increase in membrane phospholipids. In addition, the quiescent pah1Δ mutant cells had 3-fold higher levels of mitochondrial superoxide and cellular lipid hydroperoxides, had reduced activities of superoxide dismutase 2 and catalase, and were hypersensitive to hydrogen peroxide. Consequently, the pah1Δ mutant had a shortened chronological life span. In addition, the loss of Tsa1 thioredoxin peroxidase caused a synthetic growth defect with the pah1Δ mutation. The shortened chronological life span of the pah1Δ mutant along with its growth defect on non-fermentable carbon sources and hypersensitivity to hydrogen peroxide was suppressed by the loss of Dgk1 diacylglycerol kinase, indicating that the underpinning of pah1Δ mutant defects was the excess synthesis of membrane phospholipids. PMID:26338708

Evaluation of polyurethane foam passive air sampler (PUF) as a tool for occupational PAH measurements.

PubMed

Strandberg, Bo; Julander, Anneli; Sjöström, Mattias; Lewné, Marie; Koca Akdeva, Hatice; Bigert, Carolina

2018-01-01

Routine monitoring of workplace exposure to polycyclic aromatic hydrocarbons (PAHs) is performed mainly via active sampling. However, active samplers have several drawbacks and, in some cases, may even be unusable. Polyurethane foam (PUF) as personal passive air samplers constitute good alternatives for PAH monitoring in occupational air (8 h). However, PUFs must be further tested to reliably yield detectable levels of PAHs in short exposure times (1-3 h) and under extreme occupational conditions. Therefore, we compared the personal exposure monitoring performance of a passive PUF sampler with that of an active air sampler and determined the corresponding uptake rates (Rs). These rates were then used to estimate the occupational exposure of firefighters and police forensic specialists to 32 PAHs. The work environments studied were heavily contaminated by PAHs with (for example) benzo(a)pyrene ranging from 0.2 to 56 ng m -3 , as measured via active sampling. We show that, even after short exposure times, PUF can reliably accumulate both gaseous and particle-bound PAHs. The Rs-values are almost independent of variables such as the concentration and the wind speed. Therefore, by using the Rs-values (2.0-20 m 3 day -1 ), the air concentrations can be estimated within a factor of two for gaseous PAHs and a factor of 10 for particulate PAHs. With very short sampling times (1 h), our method can serve as a (i) simple and user-friendly semi-quantitative screening tool for estimating and tracking point sources of PAH in micro-environments and (ii) complement to the traditional active pumping methods. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Laboratory spectroscopy and astronomical significance of the fully-benzenoid PAH triphenylene and its cation

NASA Astrophysics Data System (ADS)

Kofman, V.; Sarre, P. J.; Hibbins, R. E.; ten Kate, I. L.; Linnartz, H.

2017-06-01

Triphenylene (C18H12) is a highly symmetric polycyclic aromatic hydrocarbon (PAH) molecule with a 'fully-benzenoid' electronic structure. This confers a high chemical stability compared with PAHs of similar size. Although numerous infrared and UV-vis experimental spectroscopic and theoretical studies of a wide range PAHs in an astrophysical context have been conducted, triphenylene and its radical cation have received almost no attention. There exists a huge body of spectroscopic evidence for neutral and ionised PAHs in astrophysical sources, obtained principally through detection of infrared emission features that are characteristic of PAHs as a chemical class. However, it has so far not proved possible to identify spectroscopically a single isolated PAH in space, although PAHs including triphenylene have been detected mass spectrometrically in meteorites. In this work we focus on recording laboratory electronic spectra of neutral and ionised triphenylene between 220 and 780 nm, trapped in H2O ice and solid argon at 12 K. The studies are motivated by the potential for spectroscopic astronomical detection of electronic absorption spectra of PAHs in ice mantles on interstellar grains as discussed by Linnartz (2014), and were performed also in a cold Ar matrix to provide guidance as to whether triphenylene (particularly in its singly positively ionised form) could be a viable candidate for any of the unidentified diffuse interstellar absorption bands. Based on the argon-matrix experimental results, comparison is made with previously unpublished astronomical spectra near 400 nm which contain broad interstellar absorption features consistent with the predictions from the laboratory matrix spectra, thus providing motivation for the recording of gas-phase electronic spectra of the internally cold triphenylene cation.

Polycyclic aromatic hydrocarbons (PAHs) in water from three estuaries of China: Distribution, seasonal variations and ecological risk assessment.

PubMed

Yan, Jinxia; Liu, Jingling; Shi, Xuan; You, Xiaoguang; Cao, Zhiguo

2016-08-15

The distribution, seasonal variations and ecological risk assessment of polycyclic aromatic hydrocarbons (PAHs) in water from three estuaries in Hai River Basin of China, which has been suffering from different anthropogenic pressures, were investigated. In three estuaries, the average concentration of ΣPAHs was the lowest in Luan River estuary, followed by Hai River estuary, and the highest in Zhangweixin River estuary. There were significant seasonal variations in ΣPAHs, the concentrations of ΣPAHs were higher in November than in May and August. The composition profiles of PAHs in different sites were significantly different, and illustrated seasonal variations. Generally, 2-ring (Nap) and 3-ring PAHs (Acp, Fl and Phe) were the most abundant components at most sampling sites in three estuaries. The PAHs in three estuaries were mainly originated from pyrogenic sources. A method based on toxic equivalency factors (TEFs) and risk quotient (RQ) was proposed to assess the ecological risk of ΣPAHs, with the ecological risk of individual PAHs being considered separately. The results showed that the ecological risks caused by ΣPAHs were high in Hai River estuary and Zhangweixin River estuary, and moderate in Luan River estuary. The mean values of ecological risk in August were lower than those in November. The contributions of individual PAHs to ecological risk were different in May, August and November. 3-ring and 4-ring PAHs accounted for much more ecological risk than 2-ring, 5-ring and 6-ring, although the contributions of 5-ring and 6-ring to ecological risk were higher than these to PAHs concentrations. Copyright © 2016 Elsevier Ltd. All rights reserved.

Contamination of polycyclic aromatic hydrocarbons (PAHs) in surface sediments and plants of mangrove swamps in Shenzhen, China.

PubMed

Li, Fenglan; Zeng, Xiaokang; Yang, Junda; Zhou, Kai; Zan, Qijie; Lei, Anping; Tam, Nora F Y

2014-08-30

The concentrations of 16 individual and total polycyclic aromatic hydrocarbons (∑PAHs) in sediments, roots and leaves of three mangrove swamps in Shenzhen, China, namely Futian, Baguang and Waterlands, were determined. The mean concentration of ∑PAHs in Futian (4480 ng g(-1)) was significantly higher than that in Baguang (1262 ng g(-1)) and Waterlands (2711 ng g(-1)). Among the 16 PAHs, the concentration of naphthalene was the highest. Based on the ratios of phenanthrene/anthracene and fluoranthene/pyrene, PAHs in Futian and Waterlands came from petrogenic and pyrolytic sources, while Baguang was mainly from pyrolytic. More PAHs were accumulated in leaves, as reflected by its higher mean concentration of ∑PAHs (3697 ng g(-1)) and bioconcentration factor of PAHs (BCF) (>1.5) than that in roots. The BCF values in plants collected from Futian were significantly higher than that from Waterlands. These results indicated that more attention should be paid to the PAH contamination in Futian. Copyright © 2014 Elsevier Ltd. All rights reserved.

Paleolimnological evidence of variations in deposition of atmosphere-borne Polycyclic Aromatic Hydrocarbons (PAHs) in Ireland.

PubMed

O'Dwyer, B; Taylor, D

2009-11-01

Polycyclic Aromatic Hydrocarbons (PAHs) are ubiquitous in the environment and are produced by both natural and anthropogenic processes, principally from the incomplete combustion of organic matter. Levels of emissions of PAHs from the combustion of fossil fuels have increased rapidly over the last ca. 200 years. As PAHs have detrimental environmental and human health impacts, assessing spatial and temporal variations in environmental loadings has become a pressing issue in many industrialised and industrializing countries. The current paper reports spatial and temporal variations in levels of atmospheric deposition of PAHs recorded in sediment cores from three lakes in Ireland, the locations of which were selected on the basis of known geographic differences in the deposition of atmospheric pollutants. Thirteen PAH compounds were analysed for in samples of lake sediment that were assumed to represent contemporary/recent and historical (possibly reference) levels of deposition. A third sample was selected from each core on the basis of measured levels of spheroidal carbonaceous particles, which are regarded as a direct indicator of depositions from the industrial-level combustion of fossil fuels. Chronological control was provided by the (210)Pb dating technique which also allowed for the calculation of PAH flux. For the most part, and when compared with the limited published data, measured levels of PAH depositions were relatively low. However, levels of deposition of PAHs in the west of Ireland are higher now than previously, which is in contrast to a general trend of decreasing levels in Europe.

PAH mutation spectrum and correlation with PKU manifestation in north Jiangsu province population.

PubMed

Wang, Zhen-Wen; Jiang, Shi-Wen; Zhou, Bao-Cheng

2018-02-01

Phenylketonuria (PKU) is a common autosomal recessive disorder of phenylalanine metabolism and mainly results a deficiency of phenylalanine hydroxylase gene (PAH). The incidence of various PAH mutations have race and ethnicity differences. We report a spectrum of PAH mutations complied from 35 PKU children who are all Chinese Han population from north Jiangsu in this study. All 13 exons and their flanking intron sequences of PAH were determined by Ion Torrent PGM™ sequencing. The relationship of genotype and phenotype was analyzed based on the sum of the arbitrary value (AV) values of the two alleles. We identified 61 mutations, with a frequency of 87.14%, among 70 alleles of 35 patients. The most prevalent mutations were R243Q (26.23%), R241C (9.84%) and V399V (8.20%). Furthermore, the consistency between prediction of the biochemical phenotype and the observed phenotype was 81.25%, with the highest consistency observed in classic PKU (87.50%). A significant correlation was found between pretreatment levels of phenylalanine and AV sum (r = -0.87, P < 0.05). Finally, our study constructs PAH mutation spectrum by next generation sequencing (NGS), and reveals that the PAH genotypes and biochemical phenotypes were significantly correlated. These offers facilitate the provision of appropriate genetic counseling for PKU patients. Copyright © 2017. Published by Elsevier Taiwan.

Regional modelling of polycyclic aromatic hydrocarbons: WRF-Chem-PAH model development and East Asia case studies

NASA Astrophysics Data System (ADS)

Mu, Qing; Lammel, Gerhard; Gencarelli, Christian N.; Hedgecock, Ian M.; Chen, Ying; Přibylová, Petra; Teich, Monique; Zhang, Yuxuan; Zheng, Guangjie; van Pinxteren, Dominik; Zhang, Qiang; Herrmann, Hartmut; Shiraiwa, Manabu; Spichtinger, Peter; Su, Hang; Pöschl, Ulrich; Cheng, Yafang

2017-10-01

Polycyclic aromatic hydrocarbons (PAHs) are hazardous pollutants, with increasing emissions in pace with economic development in East Asia, but their distribution and fate in the atmosphere are not yet well understood. We extended the regional atmospheric chemistry model WRF-Chem (Weather Research Forecast model with Chemistry module) to comprehensively study the atmospheric distribution and the fate of low-concentration, slowly degrading semivolatile compounds. The WRF-Chem-PAH model reflects the state-of-the-art understanding of current PAHs studies with several new or updated features. It was applied for PAHs covering a wide range of volatility and hydrophobicity, i.e. phenanthrene, chrysene and benzo[a]pyrene, in East Asia. Temporally highly resolved PAH concentrations and particulate mass fractions were evaluated against observations. The WRF-Chem-PAH model is able to reasonably well simulate the concentration levels and particulate mass fractions of PAHs near the sources and at a remote outflow region of East Asia, in high spatial and temporal resolutions. Sensitivity study shows that the heterogeneous reaction with ozone and the homogeneous reaction with the nitrate radical significantly influence the fate and distributions of PAHs. The methods to implement new species and to correct the transport problems can be applied to other newly implemented species in WRF-Chem.

PAH contamination in soils adjacent to a coal-transporting facility in Tapin district, south Kalimantan, Indonesia.

PubMed

Mizwar, Andy; Trihadiningrum, Yulinah

2015-07-01

This study was undertaken to determine the level of 16 polycyclic aromatic hydrocarbon (PAH), listed as priority pollutants by the United States Environmental Protection Agency (USEPA), in surface soils around a coal-transporting facility in the western part of South Kalimantan, Indonesia. Three composite soil samples were collected from a coal stockpile, coal-hauling road, and coal port. Identification and quantification of PAH was performed by gas chromatography-mass spectrometry. The total content of 16 USEPA-PAH ranged from 11.79 to 55.30 mg/kg with arithmetic mean value of 33.14 mg/kg and median of 32.33 mg/kg. The 16 USEPA-PAH measured levels were found to be greater compared with most of the literature values. The levels of high molecular-weight PAH (5- and 6-ring) were dominant and formed 67.77-80.69 % of the total 16 USEPA-PAH The most abundant of individual PAH are indeno[1,2,3-cd] pyrene and benzo[a]pyrene with concentration ranges of 2.11-20.56 and 1.59-17.84 mg/kg, respectively. The degree of PAH contamination and subsequent toxicity assessment suggest that the soils of the study area are highly contaminated and pose a potential health risk to humans.

Health implications of PAH release from coated cast iron drinking water distribution systems in The Netherlands.

PubMed

Blokker, E J Mirjam; van de Ven, Bianca M; de Jongh, Cindy M; Slaats, P G G Nellie

2013-05-01

Coal tar and bitumen have been historically used to coat the insides of cast iron drinking water mains. Polycyclic aromatic hydrocarbons (PAHs) may leach from these coatings into the drinking water and form a potential health risk for humans. We estimated the potential human cancer risk from PAHs in coated cast iron water mains. In a Dutch nationwide study, we collected drinking water samples at 120 locations over a period of 17 days under various operational conditions, such as undisturbed operation, during flushing of pipes, and after a mains repair, and analyzed these samples for PAHs. We then estimated the health risk associated with an exposure scenario over a lifetime. During flushing, PAH levels frequently exceeded drinking water quality standards; after flushing, these levels dropped rapidly. After the repair of cast iron water mains, PAH levels exceeded the drinking water standards for up to 40 days in some locations. The estimated margin of exposure for PAH exposure through drinking water was > 10,000 for all 120 measurement locations, which suggests that PAH exposure through drinking water is of low concern for consumer health. However, factors that differ among water systems, such as the use of chlorination for disinfection, may influence PAH levels in other locations.

Health Implications of PAH Release from Coated Cast Iron Drinking Water Distribution Systems in the Netherlands

PubMed Central

van de Ven, Bianca M.; de Jongh, Cindy M.

2013-01-01

Background: Coal tar and bitumen have been historically used to coat the insides of cast iron drinking water mains. Polycyclic aromatic hydrocarbons (PAHs) may leach from these coatings into the drinking water and form a potential health risk for humans. Objective: We estimated the potential human cancer risk from PAHs in coated cast iron water mains. Method: In a Dutch nationwide study, we collected drinking water samples at 120 locations over a period of 17 days under various operational conditions, such as undisturbed operation, during flushing of pipes, and after a mains repair, and analyzed these samples for PAHs. We then estimated the health risk associated with an exposure scenario over a lifetime. Results: During flushing, PAH levels frequently exceeded drinking water quality standards; after flushing, these levels dropped rapidly. After the repair of cast iron water mains, PAH levels exceeded the drinking water standards for up to 40 days in some locations. Conclusions: The estimated margin of exposure for PAH exposure through drinking water was > 10,000 for all 120 measurement locations, which suggests that PAH exposure through drinking water is of low concern for consumer health. However, factors that differ among water systems, such as the use of chlorination for disinfection, may influence PAH levels in other locations. PMID:23425894

Removal of polycyclic aromatic hydrocarbons (PAHs) from industrial sludges in the ambient air conditions: automotive industry.

PubMed

Karaca, Gizem; Tasdemir, Yucel

2013-01-01

Removal of polycyclic aromatic hydrocarbons (PAHs) existed in automotive industry treatment sludge was examined by considering the effects of temperature, UV, titanium dioxide (TiO2) and diethyl amine (DEA) in different dosages (i.e., 5% and 20%) in this study. Application of TiO2 and DEA to the sludge samples in ambient environment was studied. Ten PAH (Σ10 PAH) compounds were targeted and their average value in the sludge was found to be 4480 ± 1450 ng/g dry matter (DM). Total PAH content of the sludge was reduced by 25% in the ambient air environment. Meteorological conditions, atmospheric deposition, evaporation and sunlight irradiation played an effective role in the variations in PAH levels during the tests carried out in ambient air environment. Moreover, it was observed that when the ring numbers of PAHs increased, their removal rates also increased. Total PAH level did not change with the addition of 5% DEA and only 10% decreased with 5% TiO2 addition. PAH removal ratios were 8% and 32% when DEA (20%) and TiO2 (20%) were added, respectively. It was concluded that DEA was a weak photo-sensitizer yet TiO2 was effective only at 20% dosage.

Deciphering the roles of Arabidopsis LPCAT and PAH in phosphatidylcholine homeostasis and pathway coordination for chloroplast lipid synthesis.

PubMed

Wang, Liping; Kazachkov, Michael; Shen, Wenyun; Bai, Mei; Wu, Hong; Zou, Jitao

2014-12-01

Phosphatidylcholine (PC) is a key intermediate in the metabolic network of glycerolipid biosynthesis. Lysophosphatidylcholine acyltransferase (LPCAT) and phosphatidic acid phosphatase (PAH) are two key enzymes of PC homeostasis. We report that LPCAT activity is markedly induced in the Arabidopsis pah mutant. The quadruple pah lpcat mutant, with dual defects in PAH and LPCAT, had a level of lysophosphatidylcholine (LPC) that was much higher than that in the lpcat mutants and a PC content that was higher than that in the pah mutant. Comparative molecular profile analysis of monogalactosyldiacylglycerol and digalactosyldiacylglycerol revealed that both the pah and pah lpcat mutants had increased proportions of 34:6 from the prokaryotic pathway despite differing levels of LPCAT activity. We show that a decreased representation of the C16:0 C18:2 diacylglycerol moiety in PC was a shared feature of pah and pah lpcat, and that this change in PC metabolic profile correlated with the increased prokaryotic contribution to chloroplast lipid synthesis. We detected increased PC deacylation in the pah lpcat mutant that was attributable at least in part to the induced phospholipases. Increased LPC generation was also evident in the pah mutant, but the phospholipases were not induced, raising the possibility that PC deacylation is mediated by the reverse reaction of LPCAT. We discuss possible roles of LPCAT and PAH in PC turnover that impacts lipid pathway coordination for chloroplast lipid synthesis. © 2014 National Research Council Canada. The Plant Journal © 2014 Society For Experimental Biology and John Wiley & Sons.

Efficiency of butyl rubber sorbent to remove the PAH toxicity.

PubMed

Okay, O S; Özdemir, P; Yakan, S D

2011-01-01

Large amounts of polycyclic aromatic hydrocarbons (PAHs) have been released to the marine environment as a result of oil spills and from other sources including wastewaters, surface runoff, industrial processes, atmospheric deposition, biosynthesis, and natural events such as forest fires. PAHs have been known to affect a variety of biological processes and can be potent cell mutagens/carcinogens and toxic. In this study, PAH toxicity removal was investigated by using a novel macroporous butyl rubber (BR) sorbent. To find out the toxicity removal efficiency of the sorbents, the toxicity tests with Vibrio fisheri (luminescence bacteria) and Phaeodactylum tricornutum (marine algae) were applied to the acenaphthene (Ace) and phenanthrene (Phen) solutions in seawater (Ace: 500- 1000 μg/L; Phen; 100-1000 μg/L) before and after sorbent applications. Additionally, lysosomal stability and filtration rate biomarker techniques were applied to the mussels (Mytilus galloprovincialis) exposed to 1000 μg/L Phen solution and bioaccumulation was measured. The results showed that the toxicity of the PAH solutions decreased 50-100 percent depending on the concentration of the solutions and organisms. Phaeodactylum was found as the most sensitive organism to Phen and Ace. Since the application of BR sorbent removed the Phen from the solution, the bioaccumulated Phen amount in the mussels decreased accordingly.

Levels, trends and health concerns of atmospheric PAHs in Europe

NASA Astrophysics Data System (ADS)

Garrido, Adrián; Jiménez-Guerrero, Pedro; Ratola, Nuno

2014-12-01

Changes in climate can affect the concentration patterns of polycyclic aromatic hydrocarbons (PAHs) by altering the dispersion (wind speed, mixing layer height, convective fronts), deposition by precipitation, dry deposition, photochemistry, natural emissions and background concentrations. This means the evolution trends of these pollutants have to be studied under a multi-scale perspective, allowing the establishment of transport patterns and distribution of PAHs. In this sense, this work tries to unveil the atmospheric behaviour of these pollutants using temporal data series collected in different stations from the European Monitoring and Evaluation Programme (EMEP) air sampling network. These sites are thought to avoid the direct influence of emitting areas (background stations), allowing the study of long-range transport effects, intra- and trans-annual variability, relationships between concentrations patterns and meteorological variables and latitudinal gradients of PAH levels in Europe. Overall, a typical high concentration pattern was found for the colder months (and an opposite behaviour is found for summertime). Negative trends were detected over high latitudes, for instance, in Svalbard (Norway), whereas for the United Kingdom the pattern is the inverse. Also, negative latitudinal gradients were observed in 4 of the 15 PAHs studied. Finally, air quality parameters revealed concern over human health issues, given the recent increase of BaP levels in Europe.

PAHs content of sewage sludge in Europe and its use as soil fertilizer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suciu, Nicoleta A., E-mail: nicoleta.suciu@unicatt.it; Lamastra, Lucrezia; Trevisan, Marco

2015-07-15

Highlights: • Sewage sludge contamination by PAHs may restrict its use as soil fertilizer. • Long term data concerning sewage sludge contamination by PAHs is lacking. • Literature review for EU countries and monitoring data for Italy is presented. • Focus PEARL model was used to simulate B(a)Pyr, the most toxic PAH, fate in soil. • The simulated B(a)Pyr soil concentration was much lower than its LOEC for soil organisms. - Abstract: The European Commission has been planning limits for organic pollutants in sewage sludge for 14 years; however no legislation has been implemented. This is mainly due to lackmore » of data on sewage sludge contamination by organic pollutants, and possible negative effects to the environment. However, waste management has become an acute problem in many countries. Management options require extensive waste characterization, since many of them may contain compounds which could be harmful to the ecosystem, such as heavy metals, organic pollutants. The present study aims to show the true European position, regarding the polycyclic aromatic hydrocarbons (PAHs) content of sewage sludge, by comparing the Italian PAHs content with European Union countries, and at assessing the suitability of sewage sludge as soil fertilizer. The FOCUS Pearl model was used to estimate the concentration of benzo [a] pyrene (B(a)Pyr), the most toxic PAH in soil, and its exposure to organisms was then evaluated. The simulated B(a)Pyr and PAHs, expressed as B(a)Pyr, concentrations in soil were much lower than the B(a)Pyr’s most conservative lowest observable effect concentration (LOEC) for soil organisms. Furthermore, the results obtained indicate that it is more appropriate to apply 5 t ha{sup −1} sewage sludge annually than 15 t ha{sup −1} triennially. Results suggest, the EU maximum recommended limit of 6 mg kg{sup −1} PAHs in sewage sludge, should be conservative enough to avoid groundwater contamination and negative effects on soil organisms.« less

Systemic exposure to PAHs and benzene in firefighters suppressing controlled structure fires.

PubMed

Fent, Kenneth W; Eisenberg, Judith; Snawder, John; Sammons, Deborah; Pleil, Joachim D; Stiegel, Matthew A; Mueller, Charles; Horn, Gavin P; Dalton, James

2014-08-01

Turnout gear provides protection against dermal exposure to contaminants during firefighting; however, the level of protection is unknown. We explored the dermal contribution to the systemic dose of polycyclic aromatic hydrocarbons (PAHs) and other aromatic hydrocarbons in firefighters during suppression and overhaul of controlled structure burns. The study was organized into two rounds, three controlled burns per round, and five firefighters per burn. The firefighters wore new or laundered turnout gear tested before each burn to ensure lack of PAH contamination. To ensure that any increase in systemic PAH levels after the burn was the result of dermal rather than inhalation exposure, the firefighters did not remove their self-contained breathing apparatus until overhaul was completed and they were >30 m upwind from the burn structure. Specimens were collected before and at intervals after the burn for biomarker analysis. Urine was analyzed for phenanthrene equivalents using enzyme-linked immunosorbent assay and a benzene metabolite (s-phenylmercapturic acid) using liquid chromatography/tandem mass spectrometry; both were adjusted by creatinine. Exhaled breath collected on thermal desorption tubes was analyzed for PAHs and other aromatic hydrocarbons using gas chromatography/mass spectrometry. We collected personal air samples during the burn and skin wipe samples (corn oil medium) on several body sites before and after the burn. The air and wipe samples were analyzed for PAHs using a liquid chromatography with photodiode array detection. We explored possible changes in external exposures or biomarkers over time and the relationships between these variables using non-parametric sign tests and Spearman tests, respectively. We found significantly elevated (P < 0.05) post-exposure breath concentrations of benzene compared with pre-exposure concentrations for both rounds. We also found significantly elevated post-exposure levels of PAHs on the neck compared with pre

Characteristics of PAH tar oil contaminated soils-Black particles, resins and implications for treatment strategies.

PubMed

Trellu, Clément; Miltner, Anja; Gallo, Rosita; Huguenot, David; van Hullebusch, Eric D; Esposito, Giovanni; Oturan, Mehmet A; Kästner, Matthias

2017-04-05

Tar oil contamination is a major environmental concern due to health impacts of polycyclic aromatic hydrocarbons (PAH) and the difficulty of reaching acceptable remediation end-points. Six tar oil-contaminated soils with different industrial histories were compared to investigate contamination characteristics by black particles. Here we provide a simple method tested on 6 soils to visualize and identify large amounts of black particles (BP) as either solid aggregates of resinified and weathered tar oil or various wood/coke/coal-like materials derived from the contamination history. These materials contain 2-10 times higher PAH concentrations than the average soil and were dominantly found in the sand fraction containing 42-86% of the total PAH. The PAH contamination in the different granulometric fractions was directly proportional to the respective total organic carbon content, since the PAH were associated to the carbonaceous particulate materials. Significantly lower (bio)availability of PAH associated to these carbonaceous phases is widely recognized, thus limiting the efficiency of remediation techniques. We provide a conceptual model of the limited mass transfer of PAH from resinated tar oil phases to the water phase and emphasize the options to physically separate BP based on their lower bulk density and slower settling velocity. Copyright © 2017 Elsevier B.V. All rights reserved.

Relationship between the water-exchangeable fraction of PAH and the organic matter composition of sediments.

PubMed

Belles, Angel; Alary, Claire; Mamindy-Pajany, Yannick; Abriak, Nor-Edine

2016-12-01

The sorption of PAH on 12 different sediments was investigated and was correlated to their corresponding organic matter (OM) content and quality. For this purpose, the OM was precisely characterized using thermal analysis consisting in the successive combustion and quantification of the increasingly thermostable fractions of the OM. Simultaneously, the water-exchangeable fraction of the sorbed PAH defined as the amount of PAH freely exchanged between the water and the sediment (by opposition to the PAH harshly sorbed to the sediments particles) was determined using a passive sampler methodology recently developed. The water concentrations, when the sediment-water system is equilibrated, were also assessed which allows the determination of the sediment-water distribution coefficients without artifacts introduced by the non water-exchangeable fraction of PAH. Hence, the present study provides the distribution coefficients of PAH between the water and 4 different OM fractions combusted at a specific temperature range. The calculated distribution coefficients demonstrate that the sedimentary OM combusted at the intermediate temperature range (between 300 °C and 450 °C) drives the reversible sorption of PAH while the inferred sorption to the OM combusted at a lower and higher temperature range does not dominate the partitioning process. Copyright © 2016 Elsevier Ltd. All rights reserved.

Biochar reduces the bioaccumulation of PAHs from soil to carrot (Daucus carota L.) in the rhizosphere: A mechanism study.

PubMed

Ni, Ni; Song, Yang; Shi, Renyong; Liu, Zongtang; Bian, Yongrong; Wang, Fang; Yang, Xinglun; Gu, Chenggang; Jiang, Xin

2017-12-01

The aim of this study was to reveal the mechanisms on how biochar reduces bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) in tuberous vegetables. Corn straw-derived biochar pyrolyzed at 300°C (CB300) or bamboo-derived biochar pyrolyzed at 700°C (BB700) was amended into PAH-contaminated soil planted with carrot (Daucus carota L.). After 150days, 2% CB300 or 2% BB700 amendments significantly reduced the bioaccumulation of PAHs in carrot root (p<0.05), especially for high-molecular-weight PAHs. In the non-rhizosphere, either CB300 or BB700 suppressed PAH dissipation and decreased the bioavailability via adsorption processes. Compared to the control, the total concentration of PAHs in the rhizosphere was higher in the 2% BB700 treatment but the bioavailable concentration was lower. This indicates that BB700 decreased the bioavailability of PAHs primarily via immobilization (adsorption processes). By contrast, the total and bioavailable PAH concentrations were both lower in the 2% CB300 treatment than those in the control. The abundance of bacteria such as Arthrobacter and Flavobacterium and the total number of genes playing important roles in microbial PAH degradation processes increased significantly (p<0.05), which were likely responsible for the rapid dissipation of PAHs in the 2% CB300 treatment in the rhizosphere. These results indicate that CB300 decreased the PAH bioavailability primarily via increasing degradation of PAHs by indigenous microorganisms. The two biochars both showed better effectiveness at reducing the bioavailability of high-molecular-weight PAHs than the low-molecular-weight PAHs in the rhizosphere. Therefore, the mechanisms on how biochar reduces the PAH uptake into carrot are dependent on the type of biochar (e.g., pyrolysis temperature and feedstock) and root presence. Copyright © 2017 Elsevier B.V. All rights reserved.

Is received dose from ingested soil independent of soil PAH concentrations?-Animal model results.

PubMed

Peters, Rachel E; James, Kyle; Cave, Mark; Wickstrom, Mark; Siciliano, Steven D

2016-09-01

Polycyclic aromatic hydrocarbon (PAH) bioavailability from ingested soils will vary between soils; however, the nature of this variation is not well characterized. A juvenile swine model was used to link external exposure to internal benzo[a]pyrene (BaP) and anthracene exposure following oral PAH ingestion of 27 different impacted site soils, soots, or spiked artificial soils. Internal exposure of BaP and anthracene, represented by area under the plasma-time curve, did not relate to soil concentration in impacted site soils, but did relate in spiked artificial soil. Point of departure modeling identified soil PAH concentrations greater than 1900 mg kg(-1) as the point where area under the curve becomes proportional to external dose. A BaP internal exposure below 1900 mg kg(-1) had an upper 95% confidence interval estimate of 33% of external exposure. Weak relationships between soil:simulated gastrointestinal fluid PAH partitioning and area under the curve values suggest that differences in internal PAH exposure between soils may not be dominated by differences in PAH partitioning. The data seem to best support exposure assessment assuming constant internal PAH exposure below soil concentrations of 1900 mg kg(-1) . However, because constant internal exposure would challenge several existing paradigms, a bioavailability estimate of 33% of the external exposure is suggested as a likely workable solution. Environ Toxicol Chem 2016;35:2261-2269. © 2016 SETAC. © 2016 SETAC.

Long term observations of PM2.5-associated PAHs: Comparisons between normal and episode days

NASA Astrophysics Data System (ADS)

Wang, Jia; Li, Xiao; Jiang, Nan; Zhang, Wenkai; Zhang, Ruiqin; Tang, Xiaoyan

2015-03-01

The pollution characteristic of fine particular matter (PM2.5) and associated polycyclic aromatic hydrocarbons (PAHs) are currently drawing a great deal of interest because of their influence on environment and health. In this study, PM2.5 was collected from 2011 to 2013 (n = 188) in a suburban area of Zhengzhou, China. 16-PAHs were analyzed to determine the concentration, seasonal variation and potential sources during normal days and episode events. The total mass of 16 PAHs and PM2.5 were in the range of 7-961 ng m-3 and 55-697 μg m-3, with a 3-year average of 174 ng m-3 and 194 μg m-3 respectively. Winter is most polluted for both PM2.5 and PAHs. Average PAH and PM2.5 concentrations during three episode events are 454 ng m-3 and 453 μg m-3, respectively, much higher than values during normal days (299 ng m-3 and 180 μg m-3, respectively). Ratios of Σ16PAH/PM2.5 varied with seasons and concentrations of PM2.5, but showed a negative correlation with PM2.5 concentrations during episode events. The dominant components of PAHs are Benzo[b]fluoranthene, Chrysene, Fluoranthene, and Benzo[k]fluoranthene, Benz[a]anthracene, Pyrene, Indeno(1,2,3-cd)pyrene and their total concentrations vary from 27 to 342 ng m-3, accounting for 58-82% (average = 73%) of 16 PAHs. The Benzo[a]pyrene (Bap) concentration obtained was 9.4 ng m-3 (3-year average), exceeding nearly one order of magnitude of ambient air BaP standard (annual average: 1.0 ng m-3) in China. Diagnose ratios and Positive Matrix Factorization results show that coal combustion, vehicles, coking plant, and biomass burning are main sources for PAHs in this area. The high concentrations of PM2.5 and PAHs, especially during episode events, reflected a potential health problem for nearby public and the necessity of air pollution control for both stationary and mobile sources.

Emission characteristics for gaseous- and size-segregated particulate PAHs in coal combustion flue gas from circulating fluidized bed (CFB) boiler.

PubMed

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

2018-07-01

The partitioning behavior of polycyclic aromatic hydrocarbons (PAHs) between gaseous and particulate phases from coal-fired power plants (CFPPs) is critically important to predict PAH removal by dust control devices. In this study, 16 US-EPA priority PAHs in gaseous and size-segregated particulate phases at the inlet and outlet of the fabric filter unit (FFs) of a circulating fluidized bed (CFB) boiler were analyzed. The partitioning mechanisms of PAHs between gaseous and particulate phases and in particles of different size classes were investigated. We found that the removal efficiencies of PAHs are 45.59% and 70.67-89.06% for gaseous and particulate phases, respectively. The gaseous phase mainly contains low molecular weight (LMW) PAHs (2- and 3-ring PAHs), which is quite different from the particulate phase that mainly contains medium and high molecular weight (MMW and HMW) PAHs (4- to 6-ring PAHs). The fractions of LMW PAHs show a declining trend with the decrease of particle size. The gas-particle partitioning of PAHs is primarily controlled by organic carbon absorption, in addition, it has a clear dependence on the particle sizes. Plot of log (TPAH/PM) against logD p shows that all slope values were below -1, suggesting that PAHs were mainly adsorbed to particulates. The adsorption effect of PAHs in size-segregated PMs for HMW PAHs is more evident than LMW PAHs. The particle size distributions (PSDs) of individual PAHs show that most of PAHs exhibit bi-model structures, with one mode peaking in the accumulation size range (2.1-1.1 μm) and another mode peaking in coarse size range (5.8-4.7 μm). The intensities of these two peaks vary in function of ring number of PAHs, which is likely attributed to Kelvin effect that the less volatile HMW PAH species preferentially condense onto the finer particulates. The emission factor of PAHs was calculated as 3.53 mg/kg of coal burned, with overall mean EF PAH of 0.55 and 2.98 mg/kg for gaseous and particulate

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

PubMed

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

2016-09-15

Emission and distribution characteristics of polycyclic aromatic hydrocarbons (PAHs) were investigated during municipal solid waste (MSW) and coal combustion alone and MSW/coal blend (MSW weight fraction of 25%) co-combustion within a temperature range of 500°C-900°C. The results showed that for all combustion experiments, flue gas occupied the highest proportion of total PAHs and fly ash contained more high-ring PAHs. Moreover, the 3- and 4-ring PAHs accounted for the majority of total PAHs and Ant or Phe had the highest concentrations. Compared to coal, MSW combustion generated high levels of total PAHs with the range of 111.28μg/g-10,047.22μg/g and had high toxicity equivalent value (TEQ). MSW/coal co-combustion generated the smallest amounts of total PAHs and had the lowest TEQ than MSW and coal combustion alone. Significant synergistic interactions occurred between MSW and coal during co-combustion and the interactions suppressed the formation of PAHs, especially hazardous high-ring PAHs and decreased the TEQ. The present study indicated that the reduction of the yield and toxicity of PAHs can be achieved by co-combustion of MSW and coal. Copyright © 2016 Elsevier B.V. All rights reserved.

The diversity of PAH-degrading bacteria in a deep-sea water column above the Southwest Indian Ridge.

PubMed

Yuan, Jun; Lai, Qiliang; Sun, Fengqin; Zheng, Tianling; Shao, Zongze

2015-01-01

The bacteria involved in organic pollutant degradation in pelagic deep-sea environments are largely unknown. In this report, the diversity of polycyclic aromatic hydrocarbon (PAH)-degrading bacteria was analyzed in deep-sea water on the Southwest Indian Ridge (SWIR). After enrichment with a PAH mixture (phenanthrene, anthracene, fluoranthene, and pyrene), nine bacterial consortia were obtained from depths of 3946-4746 m. While the consortia degraded all four PAHs when supplied in a mixture, when PAHs were tested individually, only phenanthrene supported growth. Thus, degradation of the PAH mixture reflected a cometabolism of anthracene, fluoranthene, and pyrene with phenanthrene. Further, both culture-dependent and independent methods revealed many new bacteria involved in PAH degradation. Specifically, the alpha and gamma subclasses of Proteobacteria were confirmed as the major groups within the communities. Additionally, Actinobacteria, the CFB group and Firmicutes were detected. Denaturing Gradient Gel Electrophoresis (DGGE) analysis showed that bacteria closely affiliated with Alcanivorax, Novosphingobium, and Rhodovulum occurred most frequently in different PAH-degrading consortia. By using general heterotrophic media, 51 bacteria were isolated from the consortia and of these 34 grew with the PAH mixture as a sole carbon source. Of these, isolates most closely related to Alterierythrobacter, Citricella, Erythrobacter, Idiomarina, Lutibacterium, Maricaulis, Marinobacter, Martelella, Pseudidiomarina, Rhodobacter, Roseovarius, Salipiger, Sphingopyxis, and Stappia were found to be PAH degraders. To the best of our knowledge, this is the first time these bacteria have been identified in this context. In summary, this report revealed significant diversity among the PAH-degrading bacteria in the deep-sea water column. These bacteria may play a role in PAH removal in deep-sea environments.

The diversity of PAH-degrading bacteria in a deep-sea water column above the Southwest Indian Ridge

PubMed Central

Yuan, Jun; Lai, Qiliang; Sun, Fengqin; Zheng, Tianling; Shao, Zongze

2015-01-01

The bacteria involved in organic pollutant degradation in pelagic deep-sea environments are largely unknown. In this report, the diversity of polycyclic aromatic hydrocarbon (PAH)-degrading bacteria was analyzed in deep-sea water on the Southwest Indian Ridge (SWIR). After enrichment with a PAH mixture (phenanthrene, anthracene, fluoranthene, and pyrene), nine bacterial consortia were obtained from depths of 3946–4746 m. While the consortia degraded all four PAHs when supplied in a mixture, when PAHs were tested individually, only phenanthrene supported growth. Thus, degradation of the PAH mixture reflected a cometabolism of anthracene, fluoranthene, and pyrene with phenanthrene. Further, both culture-dependent and independent methods revealed many new bacteria involved in PAH degradation. Specifically, the alpha and gamma subclasses of Proteobacteria were confirmed as the major groups within the communities. Additionally, Actinobacteria, the CFB group and Firmicutes were detected. Denaturing Gradient Gel Electrophoresis (DGGE) analysis showed that bacteria closely affiliated with Alcanivorax, Novosphingobium, and Rhodovulum occurred most frequently in different PAH-degrading consortia. By using general heterotrophic media, 51 bacteria were isolated from the consortia and of these 34 grew with the PAH mixture as a sole carbon source. Of these, isolates most closely related to Alterierythrobacter, Citricella, Erythrobacter, Idiomarina, Lutibacterium, Maricaulis, Marinobacter, Martelella, Pseudidiomarina, Rhodobacter, Roseovarius, Salipiger, Sphingopyxis, and Stappia were found to be PAH degraders. To the best of our knowledge, this is the first time these bacteria have been identified in this context. In summary, this report revealed significant diversity among the PAH-degrading bacteria in the deep-sea water column. These bacteria may play a role in PAH removal in deep-sea environments. PMID:26379634

Black tattoos entail substantial uptake of genotoxicpolycyclic aromatic hydrocarbons (PAH) in human skin and regional lymph nodes.

PubMed

Lehner, Karin; Santarelli, Francesco; Vasold, Rudolf; Penning, Randolph; Sidoroff, Alexis; König, Burkhard; Landthaler, Michael; Bäumler, Wolfgang

2014-01-01

Hundreds of millions of people worldwide have tattoos, which predominantly contain black inks consisting of soot products like Carbon Black or polycyclic aromatic hydrocarbons (PAH). We recently found up to 200 μg/g of PAH in commercial black inks. After skin tattooing, a substantial part of the ink and PAH should be transported to other anatomical sites like the regional lymph nodes. To allow a first estimation of health risk, we aimed to extract and quantify the amount of PAH in black tattooed skin and the regional lymph nodes of pre-existing tattoos. Firstly, we established an extraction method by using HPLC-DAD technology that enables the quantification of PAH concentrations in human tissue. After that, 16 specimens of human tattooed skin and corresponding regional lymph nodes were included in the study. All skin specimen and lymph nodes appeared deep black. The specimens were digested and tested for 20 different PAH at the same time.PAH were found in twelve of the 16 tattooed skin specimens and in eleven regional lymph nodes. The PAH concentration ranged from 0.1-0.6 μg/cm2 in the tattooed skin and 0.1-11.8 μg/g in the lymph nodes. Two major conclusions can be drawn from the present results. Firstly, PAH in black inks stay partially in skin or can be found in the regional lymph nodes. Secondly, the major part of tattooed PAH had disappeared from skin or might be found in other organs than skin and lymph nodes. Thus, beside inhalation and ingestion, tattooing has proven to be an additional, direct and effective route of PAH uptake into the human body.

PAH clearance after renal ischemia and reperfusion is a function of impaired expression of basolateral Oat1 and Oat3.

PubMed

Bischoff, Ariane; Bucher, Michael; Gekle, Michael; Sauvant, Christoph

2014-02-01

Determination of renal plasma flow (RPF) by para-aminohippurate (PAH) clearance leads to gross underestimation of this respective parameter due to impaired renal extraction of PAH after renal ischemia and reperfusion injury. However, no mechanistic explanation for this phenomenon is available. Based on our own previous studies we hypothesized that this may be due to impairment of expression of the basolateral rate limiting organic anion transporters Oat1 and Oat3. Thus, we investigated this phenomenon in a rat model of renal ischemia and reperfusion by determining PAH clearance, PAH extraction, PAH net secretion, and the expression of rOat1 and rOat3. PAH extraction was seriously impaired after ischemia and reperfusion which led to a threefold underestimation of RPF when PAH extraction ratio was not considered. PAH extraction directly correlated with the expression of basolateral Oat1 and Oat3. Tubular PAH secretion directly correlated with PAH extraction. Consequently, our data offer an explanation for impaired renal PAH extraction by reduced expression of the rate limiting basolateral organic anion transporters Oat1 and Oat3. Moreover, we show that determination of PAH net secretion is suitable to correct PAH clearance for impaired extraction after ischemia and reperfusion in order to get valid results for RPF.

Effect of copper chloride on the emissions of PCDD/Fs and PAHs from PVC combustion.

PubMed

Wang, Dongli; Xu, Xiaobai; Zheng, Minghui; Chiu, Chung H

2002-09-01

The influences of temperature, air flow and the amount of copper chloride upon the types and amount of the toxic emissions such as polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) and polycyclic aromatic hydrocarbons (PAHs) during combustion of polyvinyl chloride (PVC) were investigated. The mechanism concerning the effect of temperature and copper chloride on the PCDD/Fs and PAHs formation was discussed. The results shown that without copper chloride, trace amounts of PCDD/Fs and large amounts of PAHs were found in the emissions from the pure PVC combustion under various combustion conditions. The addition of copper chloride enhanced PCDD/Fs formation, but it seems that the formation of PAHs decreased with increasing amount of copper chloride, and greater total amount of PAHs were produced at the higher temperature under our experimental conditions.

LINKING EXPOSURE AND DOSIMETRY TO RISK FROM PHOTO-ACTIVATED TOXICITY OF PAHS

EPA Science Inventory

Hazard from photo-activation of PAHs has been well documented in aquatic organisms. Far less certain is the degree to which risk actually occurs in the field. One of the key difficulties in understanding this risk lies in quantifying exposure/dosimetry for both PAHs and UV radiat...

Urinary polycyclic aromatic hydrocarbons as a biomarker of exposure to PAHs in air: a pilot study among pregnant women.

PubMed

Nethery, Elizabeth; Wheeler, Amanda J; Fisher, Mandy; Sjödin, Andreas; Li, Zheng; Romanoff, Lovisa C; Foster, Warren; Arbuckle, Tye E

2012-01-01

Recent studies have linked increased polycyclic aromatic hydrocarbons (PAHs) in air and adverse fetal health outcomes. Urinary PAH metabolites are of interest for exposure assessment if they can predict PAHs in air. We investigated exposure to PAHs by collecting air and urine samples among pregnant women pre-selected as living in "high" (downtown and close to steel mills, n=9) and "low" (suburban, n=10) exposure areas. We analyzed first-morning urine voids from all 3 trimesters of pregnancy for urinary PAH metabolites and compared these to personal air PAH/PM(2.5)/NO(2)/NO(X) samples collected in the 3rd trimester. We also evaluated activities and home characteristics, geographic indicators and outdoor central site PM(2.5)/NO(2)/NO(X) (all trimesters). Personal air exposures to the lighter molecular weight (MW) PAHs were linked to indoor sources (candles and incense), whereas the heavier PAHs were related to outdoor sources. Geometric means of all personal air measurements were higher in the "high" exposure group. We suggest that centrally monitored heavier MW PAHs could be used to predict personal exposures for heavier PAHs only. Urine metabolites were only directly correlated with their parent air PAHs for phenanthrene (Pearson's r=0.31-0.45) and fluorene (r=0.37-0.58). Predictive models suggest that specific metabolites (3-hydroyxyfluorene and 3-hydroxyphenanthrene) may be related to their parent air PAH exposures. The metabolite 2-hydroxynaphthalene was linked to smoking and the metabolite 1-hydroxypyrene was linked to dietary exposures. For researchers interested in predicting exposure to airborne lighter MW PAHs using urinary PAH metabolites, we propose that hydroxyfluorene and hydroxyphenanthrene metabolites be considered.

Role of CYP1B1 in PAH-DNA adduct formation and breast cancer risk

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goth-Goldstein, Regine; Russell, Marion L.; Muller, A.P.

2010-04-01

This study investigated the hypothesis that increased exposure to polycyclic aromatic hydrocarbons (PAHs) increases breast cancer risk. PAHs are products of incomplete burning of organic matter and are present in cigarette smoke, ambient air, drinking water, and diet. PAHs require metabolic transformation to bind to DNA, causing DNA adducts, which can lead to mutations and are thought to be an important pre-cancer marker. In breast tissue, PAHs appear to be metabolized to their cancer-causing form primarily by the cytochrome P450 enzyme CYP1B1. Because the genotoxic impact of PAH depends on their metabolism, we hypothesized that high CYP1B1 enzyme levels resultmore » in increased formation of PAH-DNA adducts in breast tissue, leading to increased development of breast cancer. We have investigated molecular mechanisms of the relationship between PAH exposure, CYP1B1 expression and breast cancer risk in a clinic-based case-control study. We collected histologically normal breast tissue from 56 women (43 cases and 13 controls) undergoing breast surgery and analyzed these specimens for CYP1B1 genotype, PAH-DNA adducts and CYP1B1 gene expression. We did not detect any difference in aromatic DNA adduct levels of cases and controls, only between smokers and non-smokers. CYP1B1 transcript levels were slightly lower in controls than cases, but the difference was not statistically significant. We found no correlation between the levels of CYP1B1 expression and DNA adducts. If CYP1B1 has any role in breast cancer etiology it might be through its metabolism of estrogen rather than its metabolism of PAHs. However, due to the lack of statistical power these results should be interpreted with caution.« less

Effect of land use activities on PAH contamination in urban soils of Rawalpindi and Islamabad, Pakistan.

PubMed

Ud Din, Ikhtiar; Rashid, Audil; Mahmood, Tariq; Khalid, Azeem

2013-10-01

Urbanization can increase the vulnerability of soils to various types of contamination. Increased contamination of urban soils with polycyclic aromatic hydrocarbon (PAH) could relate to increased number of petrol pump stations and mechanical workshops-a phenomenon that needs to be constantly monitored. This study was undertaken to explore the soil PAH levels in Rawalpindi and Islamabad urban areas in relation to land use activities. Composite soil samples from petrol pump stations and mechanical workshops (n = 32) areas were evaluated for five PAHs--naphthalene, phenanthrene, pyrene, benzo[a]pyrene, and indeno(1,2,3-cd)pyrene-and compared with control area locations with minimum petroleum-related activity (n = 16). Surface samples up to 3 cm depth were collected and extraction of analytes was carried out using n-hexane and dichloromethane. Prior to running the samples, standards (100 μg ml(-1)) were run on HPLC to optimize signal to noise ratio using acetonitrile as mobile phase at a flow rate of 1.25 ml/min at 40 °C. Significant differences between petrol pump stations and mechanical workshop areas were observed for individual PAH as well as with control area soil samples. Naphthalene was found to be the most abundant PAH in soil, ranging from 2.47 to 24.36 mg kg(-1). Correlation between the benzo[a]pyrene (BaP) level in soil and the total PAH concentration (r = 0.82, P < 0.0001) revealed that BaP can be used as a potential marker for PAH pollution. A clear segregation between petrogenic and pyrogenic sources of contamination was observed when low molecular weight PAHs detected in soil was plotted against high molecular weight PAHs. The former source comprised lubricants and used engine oil found at mechanical workshops, whereas the latter could be mostly attributed to vehicular emission at petrol pumps. The results indicate that PAH contamination in urban areas of Rawalpindi and Islamabad has direct relevance with land use for petroleum

Evaluation of PAH contamination in soil treated with solid by-products from shale pyrolysis.

PubMed

Nicolini, Jaqueline; Khan, Muhammad Y; Matsui, M; Côcco, Lílian C; Yamamoto, Carlos I; Lopes, Wilson A; de Andrade, Jailson B; Pillon, Clenio N; Arizaga, Gregorio G Carbajal; Mangrich, Antonio S

2015-01-01

The aim of this work was to evaluate the concentrations of polycyclic aromatic hydrocarbons (PAHs) in soils to which solid shale materials (SSMs) were added as soil conditioners. The SSMs were derived from the Petrosix pyrolysis process developed by Petrobras (Brazil). An improved ultrasonic agitation method was used to extract the PAHs from the solid samples (soils amended with SSMs), and the concentrations of the compounds were determined by gas chromatography coupled to mass spectrometry (GC-MS). The procedure provided satisfactory recoveries, detection limits, and quantification limits. The two-, three-, and four-ring PAHs were most prevalent, and the highest concentration was obtained for phenanthrene (978 ± 19 μg kg(-1) in a pyrolyzed shale sample). The use of phenanthrene/anthracene and fluoranthene/pyrene ratios revealed that the PAHs were derived from petrogenic rather than pyrogenic sources. The measured PAH concentrations did not exceed national or international limit values, suggesting that the use of SSMs as soil conditioners should not cause environmental damage.

Identification of petroleum hydrocarbons using a reduced number of PAHs selected by Procrustes rotation.

PubMed

Fernández-Varela, R; Andrade, J M; Muniategui, S; Prada, D; Ramírez-Villalobos, F

2010-04-01

Identifying petroleum-related products released into the environment is a complex and difficult task. To achieve this, polycyclic aromatic hydrocarbons (PAHs) are of outstanding importance nowadays. Despite traditional quantitative fingerprinting uses straightforward univariate statistical analyses to differentiate among oils and to assess their sources, a multivariate strategy based on Procrustes rotation (PR) was applied in this paper. The aim of PR is to select a reduced subset of PAHs still capable of performing a satisfactory identification of petroleum-related hydrocarbons. PR selected two subsets of three (C(2)-naphthalene, C(2)-dibenzothiophene and C(2)-phenanthrene) and five (C(1)-decahidronaphthalene, naphthalene, C(2)-phenanthrene, C(3)-phenanthrene and C(2)-fluoranthene) PAHs for each of the two datasets studied here. The classification abilities of each subset of PAHs were tested using principal components analysis, hierarchical cluster analysis and Kohonen neural networks and it was demonstrated that they unraveled the same patterns as the overall set of PAHs. (c) 2009 Elsevier Ltd. All rights reserved.

Presence of PAHs in milk of industrial farms from Tizayuca, Hidalgo, Mexico.

PubMed

Gutiérrez, Rey; Vega, Salvador; Ortiz, Rutilio; Pérez, José Jesús; Schettino, Beatriz

2015-01-01

The objective of this study was to determine the concentrations of polycyclic aromatic hydrocarbons (PAHs) in cow's milk from industrial farms that are located near an industrial park in Hidalgo, Mexico. It was found that the concentrations of PAHs in the raw milk of cattle from industrial farms have increased in recent years. Composite samples were collected between 2008 and 2010 and analysis carried out according to 8100 EPA procedures and analyzed by gas chromatography with FID detection. The results show that combustion PAHs were mostly Ace, Acy, and Fla (0.25, 0.32, and 0.22 µg g(-1), respectively). Diagnostic ratios were used to show that the probable sources were grass and fuel combustion. The sum of concentrations of 16 individual PAHs did not breach permissible levels in milk (25 µg g(-1) according to the United States EPA), indicating a limited health risk to animals and humans in the study area. The industrial park has adequate pollutant emission regulations.

Impacts of UV radiation and photomodification on the toxicity of PAHs to the higher plant Lemna gibba (duckweed)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiaodong Huang; Dixon, D.G.; Greenberg, B.M.

1993-06-01

The toxicity of polycyclic aromatic hydrocarbons (PAHs) can be enhanced by both biotic and abiotic processes. This is exemplified by light, which, by virtue of the extensive [pi]-orbital systems of PAHs, can be a major factor in PAH toxicity. Light activation of PAHs is known to occur via photosensitization reactions and potentially by photomodification of the chemicals to more toxic species. To examine the modes of PAH action in the light and determine if the photomodified compounds are hazardous, the authors investigated the photoinduced toxicity of anthracene, phenanthrene and benzo[a]pyrene to the aquatic higher plant Lemna gibba (a duckweed). Toxicitymore » end points were inhibition of growth and extent of chlorosis. Light did indeed activated the phytotoxicity of PAHs, with UV radiation more effective than visible light. Dose-response curves based on chemical concentration and light intensity revealed the order of phytotoxic strength to be anthracene > phenanthrene > benzo[a]pyrene. To explore whether photomodified PAHs were contributing to toxicity, the chemicals were irradiated before toxicity testing. The rates of photomodification of the three PAHs were rapid, and the relative velocities were coincident with the order of toxic strength. Furthermore, the photomodified PAHs were more hazardous to Lemna than the intact compounds. Because interpretations of the potential impacts of PAHs in the environment are based mostly on measurements of the structurally intact chemicals, the severity of PAH hazards is possibly underestimated.« less

Appraisement, source apportionment and health risk of polycyclic aromatic hydrocarbons (PAHs) in vehicle-wash wastewater, Pakistan.

PubMed

Qamar, Zahir; Khan, Sardar; Khan, Anwarzeb; Aamir, Muhammad; Nawab, Javed; Waqas, Muhammad

2017-12-15

Vehicle-wash wastewater (VWW) contains elevated concentrations of different petrochemicals including polycyclic aromatic hydrocarbons (PAHs), a carcinogenic group of organic compounds. This study investigates the discharge of PAHs present in the untreated wastewater of vehicle-wash stations (VWS) located in district Peshawar, Pakistan. The data obtained was being novel with the detection of 16 USEPA PAHs (both individuals and total) and compared with earlier studies and international standards. The ∑16PAHs in wastewater from light vehicle-wash stations (LVWS) and heavy vehicle-wash stations (HVWS) ranged from 245-429μg/l and 957-1582μg/l, respectively. A significant difference (p<0.01) was observed in PAHs discharged from LVWS and HVWS. The projected ∑16PAHs discharge from both HVWS (92% of total generated PAHs) and LVWS (8%) was about 5109.9 g per annum. According to PAH diagnostic ratios, PAHs were both petrogenic (chrysene/benz(a)anthracene, low molecular weight/high molecular weight) and pyrogenic (phenanthrene/anthracene, fluoranthene/pyrene, fluoranthene/fluoranthene+pyrene) in origin. The highest toxic equivalent quotient (TEQ) value was shown by benzo(a)pyrene (21.6μg/l) followed by dibenz(ah)anthracene (9.81μg/l) in wastewater from HVWS. However, in LVWS the case was reversed with highest value (7.54μg/l) for dibenz(ah)anthracene followed by benzo(a)pyrene (3.54μg/l). The lowest TEQ value was indicated for phenanthrene (0.007μg/l) in wastewater of LVWS, while pyrene showed the lowest value (0.007μg/l) in wastewater of HVWS. The results indicated that VWS contribute significant amount of PAHs each year, which is of great concern regarding water quality, ecological and human health risk. This is the first systematic and comprehensive research related with generation of PAHs load per day, week, month and annum from VWS, their source apportionment and health effects in Pakistan. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of Substrate Character on Heterogeneous Ozone Reaction Rate with Individual PAHs and Their Reaction Mixtures

NASA Astrophysics Data System (ADS)

Holmen, B. A.; Stevens, T.

2009-12-01

Vehicle exhaust contains many unregulated chemical compounds that are harmful to human health and the natural environment, including polycyclic aromatic hydrocarbons (PAH), a class of organic compounds derived from fuel combustion that can be carcinogenic and mutagenic. PAHs have been quantified in vehicle-derived ultrafine particles (Dp<100nm), which are more toxic than larger particles and are linked to adverse health problems, including respiratory and cardiac disease. Once emitted into the atmosphere, particle-bound PAHs can undergo “aging” reactions with oxidants, such as ozone, to form more polar species. These polar reaction products include species such as quinones that can be more toxic than the parent PAH compounds. Here, 0.4ppm ozone was reacted over a 24-hour period with the 16 EPA priority PAHs plus coronene adsorbed to (i) a quartz fiber filter and (ii) NIST diesel PM. The difference in the PAH/O3 heterogeneous reaction rate resulting from the two substrates will be discussed. The experiments were completed by spiking a known PAH mixture to the solid, reacting the samples with gas-phase ozone, and determining both PAH loss over time and products formed, using thermal-desorption gas chromatography / mass spectrometry (TD-GC/MS). The individual PAHs anthracene, phenanthrene, and fluorene, adsorbed to a QFF were also separately reacted with 0.4 ppm ozone. A volatilization control and the collection of volatilized PAHs using a Tenax-packed thermal desorption vial completed the mass balance and aided determination parent-product relationships. Heterogeneous reaction products analyzed directly without derivatization indicate the formation of 9,10-anthracenedione, 9H-fluoren-9-one, and (1,1’-biphenyl)-2,2’-dicarboxaldehyde from the reaction of ozone with the PAH mix on a QFF, but only 9,10-anthracenedione was detected for the diesel PM reaction. The implications of these results for aging of diesel particulate in urban environments will be discussed.

Real-time monitoring of particles, PAH, and CO in an occupied townhouse.

PubMed

Wallace, L

2000-01-01

Beginning in October 1996, indoor and sometimes outdoor air at an occupied house in a suburban area of Virginia has been monitored continuously for particles, PAH, and CO. Two Climet monitors have been used to count particles in six size ranges between 0.3 and > 10 microns, with 1-minute averages being collected every 5 minutes. Two Ecochem PAH monitors have been used to sample for particle-bound PAHs once every minute. Also, two Langan CO monitor-data loggers have measured CO once each minute while logging the PAH data. Two Aethalometers measure black carbon. A single Scanning Mobility Particle Sizer (SMPS) measures ultrafine particles. The pairs of monitors are set up either to provide an indoor/outdoor or an upstairs office/downstairs kitchen comparison. Air exchange is occasionally measured using a Bruel & Kjaer 1302 SF6 monitor, as a parameter necessary for estimating deposition rates for particles and PAH. Results from the first 16 months of monitoring (approximately 10 M observations) include: neighborhood woodburning and morning rush hour traffic are the most important sources of PAH and black carbon outdoors; candles, matches, incense, and frying, sauteeing, broiling, deep-frying, and stir-frying are additional important indoor sources of PM. One citronella candle was an extremely powerful PAH source. Neither woodburning nor vehicles appears to be an important source of particles indoors, but frying, grilling, and sauteeing are extremely strong indoor sources, together with combustion events such as use of matches and candles. Physical movement was an important source of coarse but not fine particles. Use of the gas stove for extended periods of time led to increased CO concentrations--vehicles and woodburning were relatively minor sources in comparison. The gas oven, gas burners, and electric toaster oven were important sources of ultrafine particles (< 0.1 micron). A source-proximity effect was noted with the kitchen monitor reading two to five times

Metal-tolerant PAH-degrading bacteria: development of suitable test medium and effect of cadmium and its availability on PAH biodegradation.

PubMed

Thavamani, Palanisami; Megharaj, Mallavarapu; Naidu, Ravi

2015-06-01

The use of metal-tolerant polyaromatic hydrocarbon (PAH)-degrading bacteria is viable for mitigating metal inhibition of organic compound biodegradation in the remediation of mixed contaminated sites. Many microbial growth media used for toxicity testing contain high concentrations of metal-binding components such as phosphates that can reduce solution-phase metal concentrations thereby underestimate the real toxicity. In this study, we isolated two PAHs-degrading bacterial consortia from long-term mixed contaminated soils. We have developed a new mineral medium by optimising the concentrations of medium components to allow the bacterial growth and at the same time maintain high bioavailable metal (Cd(2+) as a model metal) in the medium. This medium has more than 60 % Cd as Cd(2+) at pH 6.5 as measured by an ion selective electrode and visual MINTEQ model. The Cd-tolerant patterns of the consortia were tested and minimum inhibitory concentration (MIC) derived. The consortium-5 had the highest MIC of 5 mg l(-1) Cd followed by consortium-9. Both cultures were able to completely metabolise 200 mg l(-1) phenanthrene in less than 4 days in the presence of 5 mg l(-1) Cd. The isolated metal-tolerant PAH-degrading bacterial cultures have great potential for bioremediation of mixed contaminated soils.

In situ modeling of PAH dynamics in agricultural soils amended with composts using the "VSOIL" platform

NASA Astrophysics Data System (ADS)

Brimo, Khaled; Ouvrard, Stéphanie; Houot, Sabine; Lafolie, François; Deschamps, Marjolaine; Benoit, Pierre; Garnier, Patricia

2017-04-01

Numerous studies have shown the presence of organic pollutants (OPs) in composts. Compost application in agricultural soil generates flux of OPs and among them polycyclic aromatic hydrocarbons (PAHs). A potential accumulation of PAHs in soils from successive compost applications could imply risks to environment. To explore and design scenarios that help land managers in their impact evaluations when composts are added in soils, there is a need to a new generation of models built from multi-modules that mimic the whole interactions between the different processes describing OP dynamic in soil. Our work is based on the implementation of an interdisciplinary global model for PAHs in soil by coupling modules describing the major physical, biochemical and biological processes influencing the fate of PAHs in soil, with modules that simulate water transfer, heat transfer, solute transport, and organic matter transformation under climatic conditions. The coupling is being facilitated by the «VSOIL» modeling platform. The steps of our modelling study are the following: 1) calibrate the field model using parameters previously estimated in laboratory completed with field data on a short period, 2) test the simulations using field experimental data, 3) build scenarios to explore the impact of PAHs accumulation in a long term (40 years). Our results show that the model can adequately predict the fate of PAHs in soil and can contribute to clarify some of unexplored aspects regarding the behavior of PAHs in soil like their mineralization and stabilization. Scenarios that predict the dynamic of PAHs in soil at long terms show a low PAH accumulation in soil after 40 years due to a high sequestration of the PAH in soils that is slightly higher for municipal solid waste composts than for green waste sludge composts.

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...

Distribution, sources and ecological risk assessment of PAHs in surface sediments from the Luan River Estuary, China.

PubMed

Zhang, Daolai; Liu, Jinqing; Jiang, Xuejun; Cao, Ke; Yin, Ping; Zhang, Xunhua

2016-01-15

The distribution, sources and risk assessment of 16 polycyclic aromatic hydrocarbons (PAHs) of surface sediments in the Luan River Estuary, China, have been investigated in the research. The results indicated that the total concentrations of 16 PAHs in surface sediments of the Luan River Estuary ranged from 5.1 to 545.1 ng g(-1)dw with a mean value of 120.8 ng g(-1)dw, which is relatively low in comparison with other estuaries around the world. The PAHs in the study area were mainly originated from pyrogenic sources. Besides, PAHs may be contaminated by petrogenic PAHs as indicated by the selected ratios of PAHs, the 2-tailed Pearson correlation analysis and principal components analysis at different sites. The result of the ecological risk assessment shows little negative effect for most individual PAHs in surface sediments of the Luan River Estuary, China. Copyright © 2015 Elsevier Ltd. All rights reserved.

Environmental exposure to polycyclic aromatic hydrocarbons (PAHs): The correlation with and impact on reproductive hormones in umbilical cord serum.

PubMed

Yin, Shanshan; Tang, Mengling; Chen, Fangfang; Li, Tianle; Liu, Weiping

2017-01-01

Polycyclic aromatic hydrocarbons (PAHs) are a type of ubiquitous pollutant with the potential ability to cause endocrine disruption that would have an adverse health impact on the general population. To assess the maternal exposure to PAHs in neonates and evaluate the possible impact of PAHs on reproductive hormone levels, the concentration of PAHs and reproductive hormone levels in the umbilical cord serum of 98 mother-infant pairs in the Shengsi Islands were investigated. The median concentration of total PAHs was determined to be 164 (Inter-Quartile Range, IQR 93.6-267) ng g -1 lipid, and 68% of the PAHs were lower-molecule congeners. The highest level was found for pyrene (PYR) and naphthalene (NAP), which contributed 54.6% of all the PAHs present in the samples. The exposure to PAHs negatively affected estradiol (E2) and Anti-Mullerian hormones (AMH) and positively affected FSH in the umbilical cord serum. The result expanded the database of the human burden of PAHs and suggested that PAHs can act as a type of Endocrine-Disrupting Chemical (EDC). These results may help to understand the complex pathways involved in disorders of human reproductive health associated with prenatal exposure to PAHs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Transboundary movement of polycyclic aromatic hydrocarbons (PAHs) in the Kuroshio Sphere of the western Pacific Ocean

NASA Astrophysics Data System (ADS)

Huang, Hu-Ching; Lee, Chon-Lin; Lai, Chin-Hsing; Fang, Meng-Der; Lai, I.-Chien

2012-07-01

Atmospheric PAHs in the Kuroshio Sphere of southern Taiwan were measured and characterized using samples collected simultaneously at four sites from February to October in 2007. Higher PAH concentrations occurred in winter (range 2.41 ± 1.85 to 40.8 ± 6.97 ng m-3) and autumn (range 1.21 ± 0.32 to 65.1 ± 57.4 ng m-3) than in summer (range 0.87 ± 0.36 to 17.7 ± 2.88 ng m-3). Comparison of the total PAH concentrations from the four sampling sites showed that the total PAH concentrations from the Kaohsiung urban site (KHU) were 1.7-4.4 times higher than those from the Kaohsiung coastal site (KHC), 3.6-26 times those from a rural coastal site (Kenting, KT), and 16.9-53.8 times those from an offshore island site (Lanyu, LY). The PAH compositional pattern, diagnostic ratios and principal component analysis indicated that the major sources of PAHs in the study area can be classified into three categories. The first is vehicular sources from local traffic, the second is natural soils, and the third is industrial activities including coke ovens and incinerator emissions. The results from back trajectories also demonstrated that atmospheric PAHs were produced by local sources but were also influenced by transboundary movement of terrestrial pollutants. The characteristics and sources of atmospheric PAHs identified in this study provide useful information for estimating the effects and transportation of PAHs in the Kuroshio Sphere.

Long-Term Monitoring of PAH Contamination in Sediment and Recovery After the Hebei Spirit Oil Spill.

PubMed

Kim, Moonkoo; Jung, Jee-Hyun; Ha, Sung Yong; An, Joon Geon; Shim, Won Joon; Yim, Un Hyuk

2017-07-01

Approximately 10,900 t of crude oil was released 10 km off the west coast of Korea after the collision between the oil tanker Hebei Spirit and a barge carrying a crane in December 2007. To assess the areal extent and temporal trends of PAH contamination, 428 sediment samples were collected from December 2007 through May 2015 for PAH analysis. Sedimentary PAH concentrations measured immediately after the spill ranged from 3.2 to 71,200 ng g -1 , with a mean of 3800 ng g -1 . Increases in PAH concentrations were observed at stations 7-23, which were heavily oiled due to tidal currents and northwesterly wind that transported the spilled oil to these locations. Mean and maximum PAH concentrations decreased drastically from 3800 to 88.5 and 71,200 to 1700 ng g -1 , respectively, 4 months after the spill. PAH concentrations highly fluctuated until September 2008 and then decreased slowly to background levels. Reduction rate was much faster at the sandy beaches (k = 0.016) than in the muddy sites (k = 0.001). In muddy sediments, low attenuation due to low flushing rate in the mostly anaerobic sediment possibly contributed the persistence of PAHs. By May 2015 (~7.5 years after the spill), mean and maximum PAH concentrations decreased by 54 and 481 times, respectively, compared with the peak concentrations. The sedimentary PAH concentrations in the monitoring area have returned to regional background levels.

The Sin3p PAH Domains Provide Separate Functions Repressing Meiotic Gene Transcription in Saccharomyces cerevisiae ▿

PubMed Central

Mallory, Michael J.; Law, Michael J.; Buckingham, Lela E.; Strich, Randy

2010-01-01

Meiotic genes in budding yeast are repressed during vegetative growth but are transiently induced during specific stages of meiosis. Sin3p represses the early meiotic gene (EMG) by bridging the DNA binding protein Ume6p to the histone deacetylase Rpd3p. Sin3p contains four paired amphipathic helix (PAH) domains, one of which (PAH3) is required for repressing several genes expressed during mitotic cell division. This report examines the roles of the PAH domains in mediating EMG repression during mitotic cell division and following meiotic induction. PAH2 and PAH3 are required for mitotic EMG repression, while electrophoretic mobility shift assays indicate that only PAH2 is required for stable Ume6p-promoter interaction. Unlike mitotic repression, reestablishing EMG repression following transient meiotic induction requires PAH3 and PAH4. In addition, the role of Sin3p in reestablishing repression is expanded to include additional loci that it does not control during vegetative growth. These findings indicate that mitotic and postinduction EMG repressions are mediated by two separate systems that utilize different Sin3p domains. PMID:20971827

Comparison of PAHs uptake by selected Monocotyledones and Dicotyledones from municipal and industrial sewage sludge.

PubMed

Gworek, Barbara; Klimczak, Katarzyna; Kijeńska, Marta; Gozdowski, Dariusz

2016-10-01

The study was focused on two goals: (i) the confirmation of the existence of a general relation between the content of polycyclic aromatic hydrocarbons (PAHs) in sewage sludge and in plants growing in it, regardless of the type and content of sewage sludge, and (ii) if so, the answer to the question whether the uptake of PAHs by plants depends on their type. To realize the set aims, the contents of PAHs in four differentiated plant species were measured, two belonging to the Monocotyledones and two belonging to Dicotyledones group, growing in municipal and industrial sewage sludge in two locations. All the investigations were carried out during the period of 3 years. The results clearly demonstrated that the uptake of PAHs by a plant depended on polyaromatic hydrocarbon concentration in the sewage sludge. The relation between accumulation coefficient of PAHs in plant material vs. the content of PAH in sewage sludge was of exponential character. The results indicate that in case of four- and five-ring PAHs, the root uptake mechanism from soil solution occurs, regardless of the type and origin of sewage sludge and the type of plant. For three-ring PAHs, we can assume for Monocotyledones that the root uptake mechanism occurs because we observe a significant correlation between the content of fluorene, phenanthrene, and anthracene in plant material and in the sewage sludge. For Dicotyledones, the correlation is insignificant, and in this case probably two mechanisms occur-the uptake by roots and by leaves.

PAHs concentration and toxicity in organic solvent extracts of atmospheric particulate matter and sea sediments.

PubMed

Ozaki, Noriatsu; Takeuchi, Shin-ya; Kojima, Keisuke; Kindaichi, Tomonori; Komatsu, Toshiko; Fukushima, Takehiko

2012-01-01

The concentration of polycyclic aromatic hydrocarbons (PAHs) and the toxicity to marine bacteria (Vibrio fischeri) were measured for the organic solvent extracts of sea sediments collected from an urban watershed area (Hiroshima Bay) of Japan and compared with the concentrations and toxicity of atmospheric particulate matter (PM). In atmospheric PM, the PAHs concentration was highest in fine particulate matter (FPM) collected during cold seasons. The concentrations of sea sediments were 0.01-0.001 times those of atmospheric PM. 1/EC50 was 1-10 L g(-1) PM for atmospheric PM and 0.1-1 L g(-1) dry solids for sea sediments. These results imply that toxic substances from atmospheric PM are diluted several tens or hundreds of times in sea sediments. The ratio of the 1/EC50 to PAHs concentration ((1/EC50)/16PAHs) was stable for all sea sediments (0.1-1 L μg(-1) 16PAHs) and was the same order of magnitude as that of FPM and coarse particulate matter (CPM). The ratio of sediments collected from the west was more similar to that of CPM while that from the east was more similar to FPM, possibly because of hydraulic differences among water bodies. The PAHs concentration pattern analyses (principal component analysis and isomer ratio analysis) were conducted and the results showed that the PAHs pattern in sea sediments was quite different to that of FPM and CPM. Comparison with previously conducted PAHs analyses suggested that biomass burning residues comprised a major portion of these other sources.

Distribution, sources, and potential toxicological significance of PAHs in drinking water sources within the Pearl River Delta.

PubMed

An, Taicheng; Qiao, Meng; Li, Guiying; Sun, Hongwei; Zeng, Xiangying; Fu, Jiamo

2011-05-01

The Pearl River Delta (PRD) region is one of the most population-dense areas in China. The safety of its drinking source water is essential to human health. Polycyclic aromatic hydrocarbons (PAHs) have attracted attention from the scientific community and the general public due to their toxicity and wide distribution in the global environment. In this work, PAHs pollution levels from the drinking source water in nine main cities within the PRD were investigated. ∑15 PAHs concentrations during the wet season varied from 32.0 to 754.8 ng L(-1) in the dissolved phase, and from 13.4 to 3017.8 ng L(-1) in the particulate phase. During the dry season, dissolved PAHs ranged from 48.1 to 113.6 ng L(-1), and particulate PAHs from 8.6 to 69.6 ng L(-1). Overall, ∑15 PAHs concentrations were extremely high in the XC and ZHQ stations during the wet season in 2008 and 2009. In most sites, PAHs originated from mixed sources. Hazard ratios based on non-cancerous and cancerous risks were extremely higher in XC compared with the others during the wet season, though they were much less than 1. Nevertheless, risks caused by the combined toxicity of ∑15 PAHs and other organics should be seriously considered. PAHs toxic equivalent quantities ranged from 0.508 to 177.077 ng L(-1).

Electrochemistry coupled to (LC-)MS for the simulation of oxidative biotransformation reactions of PAHs.

PubMed

Wigger, Tina; Seidel, Albrecht; Karst, Uwe

2017-06-01

Electrochemistry coupled to liquid chromatography and mass spectrometry was used for simulating the biological and environmental fate of polycyclic aromatic hydrocarbons (PAHs) as well as for studying the PAH degradation behavior during electrochemical remediation. Pyrene and benzo[a]pyrene were selected as model compounds and oxidized within an electrochemical thin-layer cell equipped with boron-doped diamond electrode. At potentials of 1.2 and 1.6 V vs. Pd/H 2 , quinones were found to be the major oxidation products for both investigated PAHs. These quinones belong to a large group of PAH derivatives referred to as oxygenated PAHs, which have gained increasing attention in recent years due to their high abundance in the environment and their significant toxicity. Separation of oxidation products allowed the identification of two pyrene quinone and three benzo[a]pyrene quinone isomers, all of which are known to be formed via photooxidation and during mammalian metabolism. The good correlation between electrochemically generated PAH quinones and those formed in natural processes was also confirmed by UV irradiation experiments and microsomal incubations. At potentials higher than 2.0 V, further degradation of the initial oxidation products was observed which highlights the capability of electrochemistry to be used as remediation technique. Copyright © 2017 Elsevier Ltd. All rights reserved.

Source identification and ecological impact evaluation of PAHs in urban river sediments: A case study in Taiwan.

PubMed

Tu, Y T; Ou, J H; Tsang, D C W; Dong, C D; Chen, C W; Kao, C M

2018-03-01

The Love River and Ho-Jin River, two major urban rivers in Kaohsiung City, Taiwan, are moderately to heavily polluted because different types of improperly treated wastewaters are discharged into the rivers. In this study, sediment and river water samples were collected from two rivers to investigate the river water quality and accumulation of polycyclic aromatic hydrocarbons (PAHs) in sediments. The spatial distribution, composition, and source appointment of PAHs of the sediments were examined. The impacts of PAHs on ecological system were assessed using toxic equivalence quotient (TEQ) of potentially carcinogenic PAHs (TEQ carc ) and sediment quality guidelines. The average PAHs concentrations ranged from 2161 ng/g in Love River sediment to 160 ng/g in Ho-Jin River sediment. This could be due to the fact that Love River Basin had much higher population density and pyrolytic activities. High-ring PAHs (4-6 rings) contributed to 59-90% of the total PAHs concentrations. Benzo(a)pyrene (BaP) had the highest toxic equivalence quotient (up to 188 ng TEQ/g). Moreover, the downstream sediments contained higher TEQ of total TPHs than midstream and upstream sediment samples. The PAHs were adsorbed onto the fine particles with high organic content. Results from diagnostic ratio analyses indicate that the PAHs in two urban river sediments might originate from oil/coal combustion, traffic-related emissions, and waste combustion (pyrogenic activities). Future pollution prevention and management should target the various industries, incinerators, and transportation emission in this region to reduce the PAHs pollution. Copyright © 2017 Elsevier Ltd. All rights reserved.

Concentration, composition and sources of PAHs in the coastal sediments of the exclusive economic zone (EEZ) of Qatar, Arabian Gulf.

PubMed

Soliman, Y S; Al Ansari, E M S; Wade, T L

2014-08-30

Surface sediments were collected from sixteen locations in order to assess levels and sources of polycyclic aromatic hydrocarbons (PAHs) in sediments of Qatar exclusive economic zone (EEZ). Samples were analyzed for 16 parent PAHs, 18 alkyl homologs and for dibenzothiophenes. Total PAHs concentration (∑PAHs) ranged from 2.6 ng g(-1) to 1025 ng g(-1). The highest PAHs concentrations were in sediments in and adjacent to harbors. Alkylated PAHs predominated most of the sampling locations reaching up to 80% in offshore locations. Parent PAHs and parent high molecular weight PAHs dominated location adjacent to industrial activities and urban areas. The origin of PAHs sources to the sediments was elucidated using ternary plot, indices, and molecular ratios of specific compounds such as (Ant/Phe+Ant), (Flt/Flt+Pyr). PAHs inputs to most coastal sites consisted of mixture of petroleum and combustion derived sources. However, inputs to the offshore sediments were mainly of petroleum origin. Copyright © 2014 Elsevier Ltd. All rights reserved.

Degradation of polycyclic aromatic hydrocarbons (PAHs) present in used motor oil and implications for urban runoff quality

NASA Astrophysics Data System (ADS)

Ferreira, M.; Stenstrom, M. K.; Lau, S.

2013-12-01

Polycyclic aromatic hydrocarbons (PAHs) are common organic pollutants of urban stormwater runoff due to atmospheric deposition, vehicle-related discharges, and coal tar pavement sealants. The US EPA lists sixteen PAHs as priority pollutants and seven of those are potential carcinogenic compounds. Due to their molecular structure, PAHs tend to attach to particles that will subsequently be deposited as sediments in waterways. This study focuses on the degradation of PAHs present in used motor oil. Four experimental setups were used to simulate volatilization and photooxidation in the degradation of sixteen PAHs as observed for up to 54 days. The volatilization-only experiment showed substantial reduction only in the concentration of Napthalene (Nap). However, photooxidation-only was more efficient in degrading PAHs. In this process, substantial reduction in the concentrations of Nap, Acenapthene (Anthe), Anthracene (ANT), Fluoranthene (FLT), Pyrene (PYR), Benz[a]anthracene (BaA), Benzo[a]pyrene (BaP), Indeno[1,2,3,cd]pyrene (INP), and Benz[g,h,i]perylene (BghiP) were observed as early as five days. The two volatilization-photooxidation experiments exhibited substantial reduction in the concentrations of Fluorene (FLU), Chrysene (CHR) and Benzo[b]fluoranthene (BbF), in addition to the PAHs reduced by photooxidation-only. Phenanthrene (PHE), Fluoranthene (FLT), and Benzo[b]fluoranthene (BbF) only exhibited substantial decreased concentrations after 20 days in the volatilization-photooxidation experiment. One PAH, acenapthylene (Anthy), was not detected in the original sample of used motor oil. The highest degradations were observed in the combined volatilization-photooxidation experiment. In regions with infrequent rainfall, such as Southern California, molecules of PAHs attached to highway particles will have time to undergo degradation prior to transport. Therefore, PAHs may be present in lower concentrations in highway runoff in dry climates than in rainy climates

Black Tattoos Entail Substantial Uptake of Genotoxicpolycyclic Aromatic Hydrocarbons (PAH) in Human Skin and Regional Lymph Nodes

PubMed Central

Lehner, Karin; Santarelli, Francesco; Vasold, Rudolf; Penning, Randolph; Sidoroff, Alexis; König, Burkhard; Landthaler, Michael; Bäumler, Wolfgang

2014-01-01

Hundreds of millions of people worldwide have tattoos, which predominantly contain black inks consisting of soot products like Carbon Black or polycyclic aromatic hydrocarbons (PAH). We recently found up to 200 μg/g of PAH in commercial black inks. After skin tattooing, a substantial part of the ink and PAH should be transported to other anatomical sites like the regional lymph nodes. To allow a first estimation of health risk, we aimed to extract and quantify the amount of PAH in black tattooed skin and the regional lymph nodes of pre-existing tattoos. Firstly, we established an extraction method by using HPLC – DAD technology that enables the quantification of PAH concentrations in human tissue. After that, 16 specimens of human tattooed skin and corresponding regional lymph nodes were included in the study. All skin specimen and lymph nodes appeared deep black. The specimens were digested and tested for 20 different PAH at the same time.PAH were found in twelve of the 16 tattooed skin specimens and in eleven regional lymph nodes. The PAH concentration ranged from 0.1–0.6 μg/cm2 in the tattooed skin and 0.1–11.8 μg/g in the lymph nodes. Two major conclusions can be drawn from the present results. Firstly, PAH in black inks stay partially in skin or can be found in the regional lymph nodes. Secondly, the major part of tattooed PAH had disappeared from skin or might be found in other organs than skin and lymph nodes. Thus, beside inhalation and ingestion, tattooing has proven to be an additional, direct and effective route of PAH uptake into the human body. PMID:24670978

Assessment of polycyclic aromatic hydrocarbons (PAHs) in mussels (Mytilus galloprovincialis) of Prince Islands, Marmara Sea.

PubMed

Balcıoğlu, Esra Billur

2016-08-15

In this study, PAH analyses have been conducted on indigenous mussels. Mussel samples (Mytilus galloprovincialis) have been collected from seven stations of Prince Islands during September 2015. Concentrations of total determined PAHs (sum of 16 compounds) ranged between 664 and 9083ngg(-1). The origin of PAHs has been found to be pyrolytic according to the PHE/ANT and FA/PYR ratios in Büyükada. For other islands, PAH origins have been observed as pyrolytic and petrogenic together according to the PHE/ANT, FA/PYR and BaA/CHR ratios. Copyright © 2016 Elsevier Ltd. All rights reserved.

Anxiety, Depression, and Health-Related QOL in Patients Diagnosed with PAH or CTEPH.

PubMed

Pfeuffer, Elena; Krannich, Holger; Halank, Michael; Wilkens, Heinrike; Kolb, Philipp; Jany, Berthold; Held, Matthias

2017-12-01

Pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) are life-threatening diseases with a high burden of symptoms. Although depression, anxiety, and reduced health related quality of life (HRQOL) have also been reported, a comparative analysis which explores these traits and their underlying factors was lacking. A retrospective analysis of depression, anxiety, and health related QOL was conducted using a Hospital anxiety and depression scale (HADS) as well as the SF-36 HRQOL questionnaire. Results from these tools were compared with haemodynamic and functional parameters in 70 PAH and 23 CTEPH outpatients from a German tertiary care center specializing in pulmonary hypertension. Although HRQOL was reduced in both cohorts of patients, individuals diagnosed with CTEPH scored lower in nearly all SF-36 parameters. Significance was noted in both "mental health" (p = 0.01) and "mental component summary score" (MCS) (p = 0.02). Depression was also more frequent in patients with CTEPH (56%) than in patients with PAH (30%), (p = 0.03). Overall, depression and anxiety correlated with most SF-36 scales in both PAH and CTEPH. In CTEPH, depression also correlated with the Borg Dyspnea Scale (r = 0.44, p = 0.01). These patients also had significantly lower pCO 2 levels than the PAH cohort reflecting more severe ventilation/perfusion mismatch. All other haemodynamic and functional parameters did not differ across the groups. While both cohorts of patients suffer from a reduced HRQOL as well as depression and anxiety, decreases in mental health parameters are more pronounced in the CTEPH cohort. This suggests a strong effort to improve early detection, especially in dyspneic patients with classical risk factors for CTEPH and PAH and argues for mental illness interventions alongside routine clinical care provided to patients diagnosed with PAH or CTEPH.

Persistent activation of DNA damage signaling in response to complex mixtures of PAHs in air particulate matter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jarvis, Ian W.H., E-mail: Ian.Jarvis@ki.se; Bergvall, Christoffer, E-mail: Christoffer.Bergvall@anchem.su.se; Bottai, Matteo, E-mail: Matteo.Bottai@ki.se

2013-02-01

Complex mixtures of polycyclic aromatic hydrocarbons (PAHs) are present in air particulate matter (PM) and have been associated with many adverse human health effects including cancer and respiratory disease. However, due to their complexity, the risk of exposure to mixtures is difficult to estimate. In the present study the effects of binary mixtures of benzo[a]pyrene (BP) and dibenzo[a,l]pyrene (DBP) and complex mixtures of PAHs in urban air PM extracts on DNA damage signaling was investigated. Applying a statistical model to the data we observed a more than additive response for binary mixtures of BP and DBP on activation of DNAmore » damage signaling. Persistent activation of checkpoint kinase 1 (Chk1) was observed at significantly lower BP equivalent concentrations in air PM extracts than BP alone. Activation of DNA damage signaling was also more persistent in air PM fractions containing PAHs with more than four aromatic rings suggesting larger PAHs contribute a greater risk to human health. Altogether our data suggests that human health risk assessment based on additivity such as toxicity equivalency factor scales may significantly underestimate the risk of exposure to complex mixtures of PAHs. The data confirms our previous findings with PAH-contaminated soil (Niziolek-Kierecka et al., 2012) and suggests a possible role for Chk1 Ser317 phosphorylation as a biological marker for future analyses of complex mixtures of PAHs. -- Highlights: ► Benzo[a]pyrene (BP), dibenzo[a,l]pyrene (DBP) and air PM PAH extracts were compared. ► Binary mixture of BP and DBP induced a more than additive DNA damage response. ► Air PM PAH extracts were more potent than toxicity equivalency factor estimates. ► Larger PAHs (> 4 rings) contribute more to the genotoxicity of PAHs in air PM. ► Chk1 is a sensitive marker for persistent activation of DNA damage signaling from PAH mixtures.« less