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Source apportionment of polycyclic aromatic hydrocarbons (PAHs) in surface sediments of the Rizhao coastal area (China) using diagnostic ratios and factor analysis with nonnegative constraints.  


In this study, sources of polycyclic aromatic hydrocarbons (PAHs) found in surface sediments of the Rizhao coastal area (China) were apportioned using diagnostic ratios and factor analysis with nonnegative constraints (FA-NNC). Bivariate plots of selected diagnostic ratios showed that the sources of PAHs identified in surface sediments seemed to be mixed sources dominated by petroleum-related. Literature PAH source profiles were modified based on the first-order degradation reaction in the atmosphere and sediments, and were considered as comparison for source identification. Five significant factors were determined with the diagnostic tools including coefficient of determination, cumulative percent variance and Exner function. By visually comparing PAH patterns and from the sum of squares of differences between modeled and modified literature PAH profiles, the potential sources were apportioned with the FA-NNC. The main contribution sources of PAHs originated from diesel engine (27.22%), followed by traffic emission (25.03%), gasoline engine (18.95%), coal power plant (14.77%) and coal residential (14.03%). Energy consumption was the predominant reason for PAH pollution in that region. PMID:22115615

Chen, Hai-yang; Teng, Yan-guo; Wang, Jin-sheng



Impact of oxidation and biodegradation on the most commonly used polycyclic aromatic hydrocarbon (PAH) diagnostic ratios: Implications for the source identifications.  


Based on the isomer stability during their formation, PAH diagnostic ratios have been extensively used to determine PAH contamination origin. Nevertheless, it is known that these isomers do not present the same physicochemical properties and that reactions occurring during the transport from an atmospheric source induce changes in the diagnostic ratios. Yet, little is known about reactions occurring in soils contaminated by other sources such as coal tar and coal. Innovative batch experiments of abiotic oxidation and microbial incubations were performed to discriminate independently the influence of these two major processes occurring in soils on the diagnostic ratios of major PAH sources. Three samples were studied, a coking plant soil and two major PAH sources in this soil, namely coal and coal tar. The combustion signature of the coking plant soil showed the major influence of coal tar in the soil sample composition. Some of these ratios were drastically affected by oxidation and biodegradation processes inducing a change in the source signature. The coal tar signature changed to petrogenic source after oxidation with the anthracene/(anthracene+phenanthrene) ratio. According to this ratio, the initial petrogenic signature of the coal changed to a combustion signature after the biodegradation experiment. PMID:24413049

Biache, Coralie; Mansuy-Huault, Laurence; Faure, Pierre



Century-long source apportionment of PAHs in Athabasca oil sands region lakes using diagnostic ratios and compound-specific carbon isotope signatures.  


Evaluating the impact that airborne contamination associated with Athabasca oil sands (AOS) mining operations has on the surrounding boreal forest ecosystem requires a rigorous approach to source discrimination. This study presents a century-long historical record of source apportionment of polycyclic aromatic hydrocarbons (PAHs) in dated sediments from two headwater lakes located approximately 40 and 55 km east from the main area of open pit mining activities. Concentrations of the 16 Environmental Protection Agency (EPA) priority PAHs in addition to retene, dibenzothiophene (DBT), and six alkylated groups were measured, and both PAH molecular diagnostic ratios and carbon isotopic signatures (?(13)C) of individual PAHs were used to differentiate natural from anthropogenic inputs. Although concentrations of PAHs in these lakes were low and below the Canadian Council of Ministers of the Environment (CCME) guidelines, diagnostic ratios pointed to an increasingly larger input of petroleum-derived (i.e., petrogenic) PAHs over the past 30 years concomitant with ?(13)C values progressively shifting to the value of unprocessed AOS bitumen. This petrogenic source is attributed to the deposition of bitumen in dust particles associated with wind erosion from open pit mines. PMID:23668471

Jautzy, Josué; Ahad, Jason M E; Gobeil, Charles; Savard, Martine M



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

NASA Astrophysics Data System (ADS)

Although polycyclic aromatic hydrocarbons (PAHs) are also of natural origin, in many regions their environmental concentrations have strongly increased due to human activities. These semivolatile organic compounds are generally formed during incomplete combustion. Other sources include volatilization from unburned petroleum or tire abrasion in road traffic. Among all pollutants PAHs pose the highest human health hazard in Europe (WHO, 2003). A multivariate statistical method, positive matrix factorization (PMF; Paatero, 1997), and diagnostic ratios of individual PAHs (e.g. Yunker et al., 2002) are used for PAH source identification in central Europe. To minimise confounding factors such as differences in volatility, water solubility, adsorption etc., diagnostic ratios should be restricted to PAHs of similar molecular mass (Readman et al., 1987). Furthermore, different reactivities are limiting. Nevertheless, the application of PAH diagnostic ratios is often inconclusive, because substance patterns (profiles) have not been reported for all sources and ranges for various sources overlap. The complete profiles are made use of by statistical methods such as factor analysis, UNMIX and PMF (Tauler et al., 2006). However, these methods can be unreliable, because of incomplete knowledge of source profiles and the analysis' sensitivity to the data distribution. A unique 12-year data set of concentrations of PAHs (16 individual substances, 2 phases, weekly) in air, measured at the regional observatory Košetice, Czech Republic, is examined, together with shorter time series from Leipzig (urban background) and Schwartenberg (subalpine mountain background), Germany. Also, retene and coronene as specific source markers measured in Košetice from 2006 on are included into the analysis. An extensive literature search on PAH emission profiles was conducted. This data set was accomplished by measurements at sites in the Zlínsko region, Czech Republic, which are strongly dominated by a single, well defined PAH source. By determination of the total PAH concentrations (sum of gas and particulate phases) the propagation of sampling artefacts related to PAH partitioning into statistical errors is avoided. The main results are: Major PAH source categories exhibit a significant seasonality, coronene as a marker for traffic (Bi et al., 2003) should be used with care. Long-term trends of the major PAH sources are insignificant. Literature: Bi X.H., Sheng G.Y., Peng P., Chen Y.J., Zhang Z.Q., Fu J.M., 2003. Distribution of particulate- and vapor-phase n-alkanes and polycyclic aromatic hydrocarbons in urban atmosphere of Guangzhou, China. Atmos. Environ. 37, 289-298. Paatero P. (1997): Least square formulation of robust non-negative factor analysis, Chemometrics Intelligent Lab. Systems 37, 23-35. Readman J.W., Mantoura R.F., Rhead M.M., 1987. A record of polycyclic aromatic hydrocarbon (PAH) pollution obtained from accreting sediments of the Tamar estuary, UK: evidence for non-equilibrium behaviour of PAH. Sci. Total Environ. 66, 73-94. Tauler R., Paatero P., Hopke P., Henry R.C., Spiegelman C., Park E.S., Poirot R.L., 2006. State of the art in methods and software for the identification, resolution and apportionment of contamination sources In: Summit on Environmental Modelling and Software (Proceedings of the iEMSs 3rd Biennial Meeting; Voinov A., Jakeman A.J., Rizzoli A.E., eds.), International Environmental Modelling and Software Society, Burlington, USA. WHO (2003) - World Health Organization: Health risks of persistent organic pollutants from long-range transboundary air pollution. WHO Regional Office for Europe, Copenhagen, 252 pp. Yunker M.B., Macdonald R.W., Vingarzan R., Mitchell R.H., Goyette D., Sylvestre S., 2002. PAHs in the Fraser River basin: a critical appraisal of PAH ratios as indicators of PAH source and composition. Org. Geochem. 33, 489-515.

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



Optimal sampling ratios in comparative diagnostic trials  

PubMed Central

Summary A subjective sampling ratio between the case and the control groups is not always an efficient choice to maximize the power or to minimize the total required sample size in comparative diagnostic trials.We derive explicit expressions for an optimal sampling ratio based on a common variance structure shared by several existing summary statistics of the receiver operating characteristic curve. We propose a two-stage procedure to estimate adaptively the optimal ratio without pilot data. We investigate the properties of the proposed method through theoretical proofs, extensive simulation studies and a real example in cancer diagnostic studies. PMID:24948841

Dong, Ting; Tang, Liansheng Larry; Rosenberger, William F.



[Compositions and diagnostic ratios of heavily degraded crude oil residues in contaminated soil in oilfields].  


The aims of this study were to determine the rate of degradation of crude oil in soil, to reveal the fingerprints of residual oil after long-term biodegradation, and to screen parameters for evaluation of the biodegradability residual oil. A total of 18 contaminated soil samples containing heavily degraded crude oil residuals from Daqing, Shengli and Baise oilfields were analyzed. More than 100 individual target compounds including straight-and branched-chain alkanes (n-alkanes, pristane and phytane), polycyclic aromatic hydrocarbons (PAHs), terpanes, steranes and triaromatic steranes (TAS) in residual oil were determined by gas chromatography-mass spectrometry (GC-MS). For all the soil samples, less than 10% and 30% of alkanes and PAHs remained in the residual oils relative to crude oils. Terpanes, steranes and TAS were found to be less biodegradable. Depletions decreased with increasing carbon number of n-alkanes. However, average depletions > 80% were found in n-alkanes with carbon numbers < 37. Average depletions were > 70% for 2-4 ring PAHs, while 5-6 ring PAHs were more resistant. Increase in alkylation level decreased depletion within homologues of naphthalene, phenanthrene, chrysene and Benzo[e] pyrene. GC-MS could only reveal less than 3% of the compounds of residual oils, which were mainly comprised of n-alkanes with carbon number > 20, alkylated naphthalenes and phenanthrenes, terpanes, steranes and TAS. Based on compositional characteristics of alkanes and PAHs in residual oils, 6 diagnostic ratios, which were ratios of susceptible compounds to resistant compounds or to the amounts residual oil, were proposed as the parameters for characterization of residual oils and determining the biodegradability of oils contaminated soils. PMID:22720589

Wang, Jian; Zhang, Xu; Li, Guang-He



Environmental stability of PAH source indices in pyrogenic tars  

SciTech Connect

Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental contaminants found in soil, sediments, and airborne particulates. The majority of PAHs found in modern soils and sediments arise from myriad anthropogenic petrogenic and pyrogenic sources. Tars and tar products such as creosote produced from the industrial pyrolysis of coal or oil at former manufactured gas plants (MGPs) or in coking retorts are viscous, oily substances that contain significant concentrations of PAH, usually in excess of 30% w/w. Pyrogenic tars and tar products have unique PAH patterns (source signatures) that are a function of their industrial production. Among pyrogenic materials, certain diagnostic ratios of environmentally recalcitrant 4-, 5- and 6-ring PAHs have been identified as useful environmental markers for tracking the signature of tars and petroleum in the environment. The use of selected PAH source ratios is based on the concept that PAHs with similar properties (i.e., molecular weight, partial pressure, solubility, partition coefficients, and biotic/abiotic degradation) will weather at similar rates in the environment thereby yielding stable ratios. The stability of more than 30 high molecular weight PAH ratios is evaluated during controlled studies of tar evaporation and aerobic biodegradation. The starting materials in these experiments consisted of relatively unweathered tars derived from coal and petroleum, respectively. The PAH ratios from these laboratory studies are compared to those measured in PAH residues found in tar-contaminated soils at a former MGP that operated with a carburetted water gas process.

Uhler, A.D.; Emsbo-Mattingly, S.D. [New Fields Environmental Forensics Practice, Rockland, MA (United States)



Seasonal attributes of urban soil PAHs of the Brahmaputra Valley.  


Polycyclic Aromatic Hydrocarbons (PAHs) are ubiquitous organic pollutants, which are both toxic and carcinogenic. In the present study seasonally collected composite soil samples of Guwahati city of the Brahmaputra Valley were analysed for of PAHs by HPLC column. Black carbon (BC) and organic carbon (OC) of soil samples were analysed by thermochemical oxidation method in a TOC analyzer. Mean concentrations of ?PAHs (USEPA 16) were found to be 5570168±7003, 9052±1292 and 19294±17827ngg(-1) during monsoon, pre- and post-monsoon seasons, respectively. Two- and 4-ring PAHs dominated and the 2-ring PAHs were particularly abundant during post-monsoon period. The carcinogenic potentials of PAHs were calculated as BaP equivalents, which was found to be maximum (1167.064ngBaPqg(-1)) at industrial site. Diagnostic ratios of marker species indicated for pyrogenic origins of PAHs. Sources were indentified and contribution of individual sources was quantified by multivariate hyphenated model - Principal Component Analysis-Multiple Linear Regression (PCA-MLR). Mobile sources like the vehicular traffic were found to have contributed ?63% to the PAHs load. The correlations of individual PAHs with BC or OC showed seasonal variations. High dependencies of PAHs on BC/OC ratios were found indicating that BC could be interfering with the association of PAHs and OC. However, such relationships showed seasonal bias and high positive dependencies were found during pre-monsoon period only. Strong relationships were found between PAHs and BC/OC during monsoon and post-monsoon seasons. PMID:25203734

Hussain, Karishma; Hoque, Raza Rafiqul



Diagnostic line ratios in the IC 1805 optical gas complex  

NASA Astrophysics Data System (ADS)

Large H II regions, with angular dimensions exceeding 10 pc, usually enclose numerous massive O-stars. Stellar winds from such stars are expected to play a sizeable role in the dynamical, morphological and chemical evolution of the targeted nebula. Kinematically, stellar winds remain hardly observable, i.e. the typical expansion velocities of wind-blown bubbles being often confused with other dynamical processes also regularly found H II regions. However, supersonic shock waves, developed by stellar winds, should favour shock excitation and leave a well-defined spectral signature in the ionized nebular content. In this work, the presence of stellar winds, observed through shock excitation, is investigated in the brightest portions of the Galactic IC 1805 nebula, a giant H II region encompassing at least 10 O-stars from main-sequence O9 to giant and supergiant O4. The use of the imaging Fourier transform spectrometer SpIOMM enabled the simultaneous acquisition of the spectral information associated with the H? ?6563 Å, [N II] ??6548, 6584 Å, and [S II] ??6716, 6731 Å ionic lines. Diagnostic diagrams, first introduced by Sabbadin and collaborators, were used to circumscribe portions of the nebula likely subject to shock excitation from other areas dominated by photoionization. The gas compression, expected from supersonic shocks, is investigated by comparing the pre- and post-shocked material's densities computed from the ? line ratio. The typical ? line ratio slightly exceeds the theoretical value of 3 expected in low-density regimes. To explain such behaviour, a scenario based on collisional de-excitations affecting the [N II] ?6548 Å line is proposed.

Lagrois, Dominic; Joncas, Gilles; Drissen, Laurent



The diagnostic odds ratio: a single indicator of test performance  

Microsoft Academic Search

Diagnostic testing can be used to discriminate subjects with a target disorder from subjects without it. Several indicators of diagnostic performance have been proposed, such as sensitivity and specificity. Using paired indicators can be a disadvantage in comparing the performance of competing tests, especially if one test does not outperform the other on both indicators. Here we propose the use

Afina S. Glas; Jeroen G. Lijmer; Martin H. Prins; Gouke J. Bonsel; Patrick M. M. Bossuyt



Sediment PAH: contrasting levels in the Caspian Sea and Anzali Wetland.  


A comparative study of 23 PAH congeners in sediment of the Caspian Sea coast and Anzali Wetland was conducted in 2010. Surface sediment was analyzed using chromatography and mass spectrometry. Total PAH concentrations ranged between 212 and 9009 ng g(-1) dw. Spatial distribution maps revealed that PAH levels were higher in the coastal areas of the Caspian Sea where oil related activities have been common since 1800's. Diagnostic ratios analysis indicated that PAHs largely originated from petrogenic processes. PAH toxicity level was assessed using sediment quality guidelines and toxic equivalent concentrations to determine toxic effects on marine organism. Based on these investigations, in our study areas, the probability of toxicity for benthic organisms is "low to medium". The toxic equivalent concentrations of carcinogenic PAHs varied between 11 and 231 ng TEQ/g; higher total toxic equivalent concentrations values were found in the coastal areas of the Caspian Sea. PMID:24910181

Yancheshmeh, Rokhsareh Azimi; Bakhtiari, Alireza Riyahi; Mortazavi, Samar; Savabieasfahani, Mozhgan



Application of Binary Diagnostic Ratios of Polycyclic Aromatic Hydrocarbons for Identification of Tsunami 2004 Backwash Sediments in Khao Lak, Thailand  

PubMed Central

Identification of Tsunami deposits has long been a controversial issue among geologists. Although there are many identification criteria based on the sedimentary characteristics of unequivocal Tsunami deposits, the concept still remains ambiguous. Apart from relying on some conventional geological, sedimentological, and geoscientific records, geologists need some alternative “proxies” to identify the existence of Tsunami backwash in core sediments. Polycyclic aromatic hydrocarbons (PAHs) are a class of very stable organic molecules, which can usually be presented as complex mixtures of several hundred congeners; one can assume that the “Tsunami backwash deposits” possess different fingerprints of PAHs apart from those of “typical marine sediments.” In this study, three-dimensional plots of PAH binary ratios successfully identify the Tsunami backwash deposits in comparison with those of global marine sediments. The applications of binary ratios of PAHs coupled with HCA are the basis for developing site-specific Tsunami deposit identification criteria that can be applied in paleotsunami deposits investigations. PMID:25170522



Biomonitoring airborne parent and alkylated three-ring PAHs in the Greater Cologne Conurbation I: temporal accumulation patterns.  


Polycyclic aromatic hydrocarbons (PAHs) comprise an important group of air pollutants, with three-ring components (PAH-3) often dominating. Spatiotemporal variation in atmospheric PAH-3 can be analyzed by biomonitoring but high vapour pressure and low octanol-air-partitioning of PAH-3 cause dynamic accumulation on plant surfaces. This study for the first time shows that PAH-3 exhibit systematic accumulation trends on pine needles of 3-48 months of exposure time at six sites in Germany. Correlation of needle exposure time with PAH-3 concentration was r(2)=0.83 for phenanthrene and methylphenanthrenes, r(2)=0.77 for cyclopenta[def]phenanthrene, r(2)=0.60 for dibenzothiophene, r(2)=0.57 for dimethylphenanthrenes and r(2)=0.32 for retene. Variations in PAH-3 for summer and winter collected needles emphasize vegetation-air-partitioning influence on cumulative PAH-3 loads. PAH-3 ratios calculated for needle cohorts indicate persistence of original PAH patterns thus demonstrating the source-diagnostic potential of pine needle biomonitoring, which is utilized in part II of this study where spatial distribution of PAH-3 is investigated and related to emission sources. PMID:19157663

Lehndorff, E; Schwark, L



Baseline distributions and sources of Polycyclic Aromatic Hydrocarbons (PAHs) in the surface sediments from the Prai and Malacca Rivers, Peninsular Malaysia.  


In this study, the surface sediments of the Malacca and Prai Rivers were analyzed to identify the distributions, and sources of Polycyclic Aromatic Hydrocarbons (PAHs). The total PAH concentrations varied from 716 to 1210 and 1102 to 7938 ng g(-1)dw in the sediments of the Malacca and Prai Rivers, respectively. The PAH concentrations can be classified as moderate and high level of pollution in the sediments of the Malacca and Prai Rivers, respectively. The comparison of PAHs with the Sediment Quality Guidelines (SQGs) indicates that the PAHs in the sediments of the Malacca and Prai Rivers may have the potential to cause adverse toxicity effects on the sampled ecosystems. The diagnostic ratios of individual PAHs indicate both petrogenic- and pyrogenic-origin PAHs with dominance of pyrogenic source in both rivers. These findings demonstrate that the environmental regulations in Malaysia have effectively reduced the input of petrogenic petroleum hydrocarbons into rivers. PMID:25173594

Keshavarzifard, Mehrzad; Zakaria, Mohamad Pauzi; Hwai, Tan Shau; Yusuff, Ferdius Ferdius Mohamat; Mustafa, Shuhaimi; Vaezzadeh, Vahab; Magam, Sami M; Masood, Najat; Alkhadher, Sadeq A A; Abootalebi-Jahromi, Fatemeh



Characterization of the size-distribution of aerosols and particle-bound content of oxygenated PAHs, PAHs, and n-alkanes in urban environments in Afghanistan  

NASA Astrophysics Data System (ADS)

Air pollution is a common problem in mega-cities in Asia, resulting in high levels of particulate matter (PM). In this study, 24 h samples of airborne particulate matter (PM 2.5 and PM 10) was collected for two weeks in urban locations in Kabul and Mazar-e Sharif, Afghanistan. The samples were analyzed for twenty n-alkanes, fifteen polycyclic aromatic hydrocarbons (PAHs) and eighteen oxygenated PAHs (oxy-PAHs). The results were compared to a reference location in Umeå, Sweden. The main objectives were: to characterize the organic fraction in PM 2.5, with focus on oxy-PAHs, PAHs and n-alkanes, assess relationships between compound groups, and investigate possible source categories. Mean PM 10, levels were 260 ?g m -3, and 334 ?g m -3 and mean PM 2.5 levels were 86 ?g/m 3and 68 ?g m -3 in Kabul and Mazar-e Sharif, respectively. The higher ratio of PM 2.5 to PM 10 in Kabul than Mazar-e Sharif or Umeå was reflected in the high number of small particles, as collected by a particle counter. Kabul and Mazar-e Sharif had high levels of PAHs and oxy-PAHs compared to Umeå and previously reported data from Western countries. Generally, the highest individual levels of oxy-PAHs were found for ketones (0.27-33 ng m -3), whereas the quinone levels were lower (0.027-3.1 ng m -3). High correlations ( r > 0.96) between PAHs and oxy-PAHs were found at both locations. Diagnostics for n-alkanes, such as the carbon preference index, and the most abundant species, Cmax, and the presence of unresolved complex mixture indicated a higher contribution from coal and petroleum sources in Kabul. Models generated by principal component analysis (PCA) and positive matrix factorization (PMF) both suggested separate sources for lower molecular weight n-alkanes and higher molecular weight n-alkanes. The PAHs and the oxy-PAHs were not separated in either the PCA or the PMF models, indicating that they had similar sources and are perhaps relatively unspecific as source markers. Nevertheless, the PAHs and oxy-PAHs were good markers for bad air quality in the urban locations in Afghanistan in comparison to data from Western countries. Based on the models and diagnostic ratios it is suggested that traffic and combustion of coal and biomass were the dominating sources of the high levels of particle-bound organic compounds.

Wingfors, Håkan; Hägglund, Lars; Magnusson, Roger



Spatial distribution, potential risk assessment, and source apportionment of polycyclic aromatic hydrocarbons (PAHs) in sediments of Lake Chaohu, China.  


Twenty-nine sediment samples were collected from Lake Chaohu, a shallow eutrophic lake in Eastern China, and were analyzed for 15 priority polycyclic aromatic hydrocarbons (PAHs) to determine the spatial distribution and exposure risks of PAHs. Three receptor models, the principal component analysis-multiple linear regression (PCA-MLR) model, the positive matrix factorization (PMF) model, and the Unmix model, were used in combination with the PAHs diagnostic ratios to investigate the potential source apportionment of PAHs. A clear gradient in the spatial distribution and the potential toxicity of PAHs was observed from west to east in the sediments of Lake Chaohu. ?15PAH concentrations and the TEQ were in the range of 80.82-30 365.01 ng g(-1) d.w. and 40.77-614.03, respectively. The highest values of the aforementioned variables were attributed to urban-industrial pollution sources in the west lake region, and the levels decreased away from the river inlets. The three different models yielded excellent correlation coefficients between the predicted and measured levels of the 15 PAH compounds. Similarly, source apportionment results were derived from the three receptor models and the PAH diagnostic ratios, suggesting that the highest contribution to the PAHs was from coal combustion and wood combustion, followed by vehicular emissions. The PMF model yielded the following contributions to the PAHs from gasoline combustion, diesel combustion, unburned petroleum emissions, and wood combustion: 34.49, 24.61, 16.11, 13.01, and 11.78 %, respectively. The PMF model produced more detailed source apportionment results for the PAHs than the PCA-MLR and Unmix models. PMID:24920262

Li, Chaocan; Huo, Shouliang; Yu, Zhiqiang; Xi, Beidou; Zeng, Xiangying; Wu, Fengchang



Polycyclic aromatic hydrocarbons (PAHs) in soils from a multi-industrial city, South Korea.  


We collected soil samples at 25 sites in Ulsan, Korea to investigate the levels, patterns, spatial distribution, and sources of polycyclic aromatic hydrocarbons (PAHs) in the summer 2010. The target compounds were the 16 US-EPA priority PAHs. For the source identification of PAHs, diagnostic ratios and the positive matrix factorization (PMF) model were used. The total concentrations of PAHs ranged from 65 ng/g to 12,000 ng/g (mean: 960 ng/g, median 330 ng/g). The levels and distribution of PAHs indicated that industrial areas were more polluted than rural and urban areas. The diagnostic ratios suggested that the soil samples were contaminated by pyrogenic sources and traffic emission. According to the result of PMF, four factors were identified: gasoline and heavy oil combustion (14%), diesel combustion (54%), coke oven (23%), and coal/biomass burning (9%). Therefore, it was concluded that vehicles and industrial complexes were major sources of PAHs in Ulsan. PMID:24011990

Kwon, Hye-Ok; Choi, Sung-Deuk



Spatial distribution and source apportionment of polycyclic aromatic hydrocarbons (PAHs) in Camphor (Cinnamomum camphora) tree bark from Southern Jiangsu, China.  


The concentrations and sources of polycyclic aromatic hydrocarbons (PAHs) were investigated in Camphor tree bark from Southern Jiangsu, China. Tree bark samples were collected in August 2012. The ?15PAHs concentrations were ranged from 6.18 to 1560 ng g(-1)dry weight (dw), with an average value of 407 ng g(-1)dw. Generally, the concentrations of PAHs in the suburban areas were the highest, followed by urban and rural areas. Principal component analysis and diagnostic ratios results showed that vehicle emission, biomass and coal combustion and industrial emission were the major sources of PAHs in tree bark from Southern Jiangsu. Good correlation was found between tree bark and polyurethane foam (PUF) samplers, indicating that both of them respond well to the gas-phase PAHs monitoring. PMID:24480428

Zhou, Li; Dong, Liang; Huang, Yeru; Shi, Shuangxin; Zhang, Lifei; Zhang, Xiulan; Yang, Wenlong; Li, Lingling



Revisited abundance diagnostics in quasars: Fe II/Mg II ratios  

E-print Network

Both the Fe II UV emission in the 2000- 3000 A region [Fe II (UV)] and resonance emission line complex of Mg II at 2800 A are prominent features in quasar spectra. The observed Fe II UV/ Mg II emission ratios have been proposed as means to measure the buildup of the Fe abundance relative to that of the alpha-elements C, N, O, Ne and Mg as a function of redshift. The current observed ratios show large scatter and no obvious dependence on redshift. Thus, it remains unresolved whether a dependence on redshift exists and whether the observed Fe II UV/ Mg II ratios represent a real nucleosynthesis diagnostic. We have used our new 830-level model atom for Fe+ in photoionization calculations, reproducing the physical conditions in the broad line regions of quasars. This modeling reveals that interpretations of high values of Fe II UV/ Mg II are sensitive not only to Fe and Mg abundance, but also to other factors such as microturbulence, density, and properties of the radiation field. We find that the Fe II UV/ Mg II ratio combined with Fe II (UV)/ Fe II (Optical) emission ratio, where Fe II (Optical) denotes Fe II emission in 4000 - 6000 A can be used as a reliable nucleosynthesis diagnostic for the Fe/Mg abundance ratios for the physical conditions relevant to the broad-line regions (BLRs) of quasars. This has extreme importance for quasar observations with the Hubble Space Telescope and also with the future James Webb Space Telescope.

E. Verner; F. Bruhweiler; D. Verner; S. Johansson; T. Gull




SciTech Connect

The dynamic timescales in the solar atmosphere are shorter than the ionization and recombination times of many ions used for line ratio diagnostics of the transition region and corona. The long ionization and recombination times for these ions imply that they can be found far from their equilibrium temperatures, and spectroscopic investigations require more care before being trusted in giving correct information on local quantities, such as density and temperature. By solving the full time-dependent rate equations for an oxygen model atom in the three-dimensional numerical model of the solar atmosphere generated by the Bifrost code, we are able to construct synthetic intensity maps and study the emergent emission. We investigate the method of electron density diagnostics through line ratio analysis of the O IV 140.1 nm to the 140.4 nm ratio, the assumptions made in carrying out the diagnostics, and the different interpretations of the electron density. The results show big discrepancies between emission in statistical equilibrium and emission where non-equilibrium (NEQ) ionization is treated. Deduced electron densities are up to an order of magnitude higher when NEQ effects are accounted for. The inferred electron density is found to be a weighted mean average electron density along the line of sight and has no relation to the temperature of emission. This study shows that numerical modeling is essential for electron density diagnostics and is a valuable tool when the ions used for such studies are expected to be out of ionization equilibrium. Though this study has been performed on the O IV ion, similar results are also expected for other transition region ions.

Olluri, K.; Gudiksen, B. V.; Hansteen, V. H., E-mail: [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, NO-0315 Oslo (Norway)



Distribution and Source Apportionment of Polycyclic Aromatic Hydrocarbons (PAHs) in Forest Soils from Urban to Rural Areas in the Pearl River Delta of Southern China  

PubMed Central

The upper layer of forest soils (0–20 cm depth) were collected from urban, suburban, and rural areas in the Pearl River Delta of Southern China to estimate the distribution and the possible sources of polycyclic aromatic hydrocarbons (PAHs). Total concentrations of PAHs in the forest soils decreased significantly along the urban–suburban–rural gradient, indicating the influence of anthropogenic emissions on the PAH distribution in forest soils. High and low molecular weight PAHs dominated in the urban and rural forest soils, respectively, implying the difference in emission sources between the areas. The values of PAH isomeric diagnostic ratios indicated that forest soil PAHs were mainly originated from traffic emissions, mixed sources and coal/wood combustion in the urban, suburban and rural areas, respectively. Principal component analysis revealed that traffic emissions, coal burning and residential biomass combustion were the three primary contributors to forest soil PAHs in the Pearl River Delta. Long range transportation of PAHs via atmosphere from urban area might also impact the PAHs distribution in the forest soils of rural area. PMID:24599040

Xiao, Yihua; Tong, Fuchun; Kuang, Yuanwen; Chen, Bufeng



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

NASA Astrophysics Data System (ADS)

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.

Agudelo-Castañeda, Dayana Milena; Teixeira, Elba Calesso



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


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 the respective area. Additionally, principal component regression indicated that SO2, NO2, PM10, CO, and solar radiation had positive correlation with PAHs concentrations, while O3, temperature, relative humidity, and wind speed were negatively correlated. PMID:23184127

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



PAHs (polycyclic aromatic hydrocarbons), nitro-PAHs, and hopane and sterane biomarkers in sediments of southern Lake Michigan, USA.  


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 ?PAH14 (sum of 14 compounds) ranged from 213 to 1,291 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 ?NPAH5 concentration ranged from 2.9 to 18.6 ng/g dw, and included carcinogenic compounds 1-nitropyrene and 6-nitrochrysene. ?Sterane6 and ?Hopane5 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 metrictons per year (t/yr) of ?PAH14, ?NPAH5, ?Sterane6 and ?Hopane5, 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 NPAH levels in sediments of Lake Michigan reveals several carcinogenic compounds at modest concentrations, and a need for further work to assess potential risks to aquatic organisms. PMID:24784742

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



Data handling of GC/MS signals for characterization of PAH sources in Northern Italy aerosols.  


The paper describes the characterization of polycyclic aromatic hydrocarbons (PAHs) in atmospheric aerosol samples using Gas Chromatography-Mass Spectrometry analysis. A data handling of GC/MS signals based on Experimental Autocovariance Function (EACVF) is described in order to directly characterize PAHs with a simple and reliable method suitable for processing large batches of samples. The method was successfully applied to 42 aerosol samples collected in different seasons (summer, fall and winter) in two locations in Northern Italy: Milan, a large urban area, and Oasi Le Bine, a rural site. The reliability of the EACVF results was verified by comparison with the values computed with the conventional GC/MS signal treatment and the data of independent studies. Two main emission sources were identified and described by PAH concentration profiles: the road traffic source (TR), characterized by high contributions of FLNT, PYR and CHR, and the residential combustion (COMB) mainly containing pyrogenic high molecular weight PAHs, i.e., CHR, BaP, BeP, BbF and BkF. In addition, some PAH diagnostic ratios were directly computed for the EACVF plot, to distinguish between traffic and combustion dominated emissions, i.e. the ratios CHR/BaP, PYR/BaP and PYR/BeP. PMID:24468371

Pietrogrande, M C; Perrone, M G; Sangiorgi, G; Ferrero, L; Bolzacchini, E



Isotopic 32S/33S ratio as a diagnostic of presolar grains from novae  

NASA Astrophysics Data System (ADS)

Measurements of sulphur isotopes in presolar grains can help to identify the astrophysical sites in which these grains were formed. A more precise thermonuclear rate of the 33S(p,?)34Cl reaction is required, however, to assess the diagnostic ability of sulphur isotopic ratios. We have studied the 33S(3He,d)34Cl proton-transfer reaction at 25 MeV using a high-resolution quadrupole-dipole-dipole-dipole magnetic spectrograph. Deuteron spectra were measured at ten scattering angles between 10° and 55°. Twenty-four levels in 34Cl over Ex=4.6-5.9 MeV were observed, including three levels for the first time. Proton spectroscopic factors were extracted for the first time for levels above the 33S + p threshold, spanning the energy range required for calculations of the thermonuclear 33S(p,?)34Cl rate in classical nova explosions. We have determined a new 33S(p,?)34Cl rate using a Monte Carlo method and have performed new hydrodynamic nova simulations to determine the impact on nova nucleosynthesis of remaining nuclear physics uncertainties in the reaction rate. We find that these uncertainties lead to a factor of ?5 variation in the 33S(p,?)34Cl rate over typical nova peak temperatures, and variation in the ejected nova yields of Ssbnd Ca isotopes by ?20%. In particular, the predicted 32S/33S ratio is 110-130 for the nova model considered, compared to 110-440 with previous rate uncertainties. As recent type II supernova models predict ratios of 130-200, the 32S/33S ratio may be used to distinguish between grains of nova and supernova origin.

Parikh, A.; Wimmer, K.; Faestermann, T.; Hertenberger, R.; José, J.; Wirth, H.-F.; Hinke, C.; Krücken, R.; Seiler, D.; Steiger, K.; Straub, K.



Isotopic 32S/33S ratio as a diagnostic of presolar grains from novae  

E-print Network

Measurements of sulphur isotopes in presolar grains can help to identify the astrophysical sites in which these grains were formed. A more precise thermonuclear rate of the 33S(p,gamma)34Cl reaction is required, however, to assess the diagnostic ability of sulphur isotopic ratios. We have studied the 33S(3He,d)34Cl proton-transfer reaction at 25 MeV using a high-resolution quadrupole-dipole-dipole-dipole magnetic spectrograph. Deuteron spectra were measured at ten scattering angles between 10 and 55 degrees. Twenty-four levels in 34Cl over Ex = 4.6 - 5.9 MeV were observed, including three levels for the first time. Proton spectroscopic factors were extracted for the first time for levels above the 33S+p threshold, spanning the energy range required for calculations of the thermonuclear 33S(p,gamma)34Cl rate in classical nova explosions. We have determined a new 33S(p,gamma)34Cl rate using a Monte Carlo method and have performed new hydrodynamic nova simulations to determine the impact on nova nucleosynthesis of remaining nuclear physics uncertainties in the reaction rate. We find that these uncertainties lead to a factor of less than 5 variation in the 33S(p,gamma)34Cl rate over typical nova peak temperatures, and variation in the ejected nova yields of S--Ca isotopes by less than 20%. In particular, the predicted 32S/33S ratio is 110 - 130 for the nova model considered, compared to 110 - 440 with previous rate uncertainties. As recent type II supernova models predict ratios of 130 - 200, the 32S/33S ratio may be used to distinguish between grains of nova and supernova origin.

A. Parikh; K. Wimmer; T. Faestermann; R. Hertenberger; J. Jose; H. -F. Wirth; C. Hinke; R. Krucken; D. Seiler; K. Steiger; K. Straub



FE-XIII Infrared / FE-XIV Green Line Ratio Diagnostics (P55)  

NASA Astrophysics Data System (ADS) We consider the first 27-level atomic model of Fe XIII (5.9 < log Te < 6.4 K) to estimate its ground level populations, taking account of electron as well as proton collisional excitations and de-excitations, radiative cascades, radiative excitations and de-excitations. Radiative cascade is important but the effect of dilution factor is negligible at higher electron densities. The 3 P1-3P0 and 3P2-3P1 transitions in the ground configuration 3s2 3p2 of Fe XIII result in two forbidden coronal emission lines in the infrared region, namely 10747 Å and 10798 Å., while the 5303 Å green line is formed in the 3s2 3p 2 2 ground configuration of Fe XIV as a result of P3 / 2 - P1 / 2 magnetic dipole transition. The line-widths of appropriate pair of forbidden coronal emission lines observed simultaneously can be useful diagnostic tool to deduce temperature and non-thermal velocity in the large scale coronal structures using intensity ratios of the lines as the temperature signature, instead of assuming ion temperature to be equal to the electron temperature. Since the line intensity ratios IG5303/IIR10747 and IG5303/IIR10798 have very week density dependence, they are ideal monitors of temperature mapping in the solar corona.

Srivastava, A. K.; et al.



Seasonal and site-specific variation in vapour and aerosol phase PAHs over Flanders (Belgium) and their relation with anthropogenic activities  

NASA Astrophysics Data System (ADS)

The concentrations of 16 US-EPA criteria polycyclic aromatic hydrocarbons (PAHs) were monitored during various seasons at six different cities/locations in the northern part of Belgium. Pressurized liquid extraction (PLE) was used for the fast recovery of PAHs from quartz fibre filters (QFFs) and polyurethane foams (PUFs) in less than 30 min with minimum solvent consumption prior to their analysis with high-performance liquid chromatography. The concentrations of PAHs varied significantly at the studied sites and showed relation to different anthropogenic activities, such as vehicular emission (diesel/gasoline), incinerator, petroleum/oil burning, coke production, and wood/coal combustion. The annual average PAH concentration ranged from 17 (at a rural site) to 114 ng m -3 (near a petroleum harbour and industry). Most of the human carcinogenic PAHs were found to be associated with suspended particulate matter, which forms around ˜55% of the total PAH levels in aerosols. Relatively higher concentrations of PAHs were detected in aerosol samples during winter compared with other seasons, whereas no clear seasonal trend was observed for the vapour phase PAHs. This fraction is likely to be more local in origin; hence, it can be used as a site-specific characteristic. The site-specific concentrations of individual PAHs were also used in diagnostic ratio evaluations and in principal component analysis to find their relation with various anthropogenic activities. These results show that the vehicular emission is a major source of PAHs in Flanders, although other anthropogenic sources, as above, have also an impact on the total PAH levels.

Ravindra, Khaiwal; Bencs, László; Wauters, Eric; de Hoog, Johan; Deutsch, Felix; Roekens, Edward; Bleux, Nico; Berghmans, Patrick; Van Grieken, René


Diagnostic Value of Elastography Using Acoustic Radiation Force Impulse Imaging and Strain Ratio for Breast Tumors  

PubMed Central

Purpose The aim of this study was to determine whether the combination of B-mode ultrasonography (BUS), acoustic radiation force impulse (ARFI) elastography, and strain ratio (SR) provides better diagnostic performance of breast lesion differentiation than BUS alone. Methods ARFI elastography and SR evaluations were performed on patients with 157 breast lesions diagnosed by BUS from June to September 2013. BUS images were classified according to the Breast Imaging-Reporting and Data System. ARFI elastography was performed using Virtual Touch™ tissue imaging (VTI) and Virtual Touch™ tissue quantification (VTQ). In VTI mode, we evaluated the color-mapped patterns of the breast lesion and surrounding tissue. The lesions were classified into five categories by elasticity score. In VTQ mode, each lesion was assessed using shear wave velocity (SWV) measurements. SR was calculated from the lesion and comparable lateral fatty tissue. We compared the diagnostic performance of BUS alone and the combination of BUS, ARFI elastography, and SR evaluations. Results Among the 157 lesions, 40 were malignant and 117 were benign. The mean elasticity score (3.7±1.0 vs. 1.6±0.8, p<0.01), SWV (4.23±1.09 m/sec vs. 2.22±0.88 m/sec, p<0.01), and SR (5.69±1.63 vs. 2.69±1.40, p<0.01) were significantly higher for malignant lesions than benign lesions. The results for BUS combined with ARFI elastography and SR values were 97.5% sensitivity, 92.3% specificity, 93.6% accuracy, a 79.6% positive predictive value (PPV), and a 99.1% negative predictive value. The combination of the 3 radiologic examinations yielded superior specificity, accuracy, and PPV compared to BUS alone (p<0.01 for each). Conclusion ARFI elastography and SR evaluations showed significantly different mean values for benign and malignant lesions. Moreover, these two modalities complemented BUS and improved the diagnostic performance of breast lesion detection. Therefore, ARFI elastography and SR evaluations can be used as complementary modalities to make more accurate breast lesion diagnoses. PMID:24744801

Kim, Yoon Seok; Park, Jung Gu; Kim, Beom Su; Lee, Chung Han



Indoor/outdoor relationships and diurnal/nocturnal variations in water-soluble ion and PAH concentrations in the atmospheric PM2.5 of a business office area in Jinan, a heavily polluted city in China  

NASA Astrophysics Data System (ADS)

Indoor/outdoor and diurnal/nocturnal variations in PM2.5 and associated water-soluble ions and polycyclic aromatic hydrocarbons (PAHs) were examined in a business office during the summer and autumn of 2010 in Jinan, China. Both indoor and outdoor PM2.5 levels were higher than the value recommended by the WHO, and outdoor sources were found to be the major contributors to indoor PM2.5. SO42-, NO3- and NH4+ were the dominant water-soluble ions in both indoor and outdoor particles. During daytime, NO3- mainly came from indoor sources, which was related to the temperature difference between the indoor and outdoor air. During daytime, the 15 monitored PAHs were all largely from indoor sources, while during nighttime, the 3 -4-ring PAHs were mainly generated indoors and the 5-6-ring PAHs predominantly came from the outdoor air. The diurnal/nocturnal variations of PAHs suggested that gas/particle partitioning driven by temperature makes a significant contribution to the variation in PAH concentrations. The diagnostic ratios revealed that biomass burning had an important contribution to outdoor PAH concentrations in autumn. The results of a risk assessment of PAH pollution suggested that indoor PAHs present more carcinogenic and mutagenic risks during daytime. Our results indicated that serious indoor air pollution in a business office presents a high health risk for workers.

Zhu, Yanhong; Yang, Lingxiao; Meng, Chuanping; Yuan, Qi; Yan, Chao; Dong, Can; Sui, Xiao; Yao, Lan; Yang, Fei; Lu, Yaling; Wang, Wenxing



Observation of Helical Structure by Imaging Diagnostics in a Low-Aspect-Ratio Reversed Field Pinch  

NASA Astrophysics Data System (ADS)

Study of helical structure has been in progress in shallow reversal reversed field pinch (RFP) plasmas in a low-aspect-ratio machine RELAX (R/a = 0.5 m/0.25 m, A = 2) by using visible light and soft-X-ray (SXR) imaging diagnostics. Simple helix and its toroidal rotation have been observed in tangential visible light images taken by a high-speed camera. Similar simple filament structures have also been observed in tangential images obtained by a pin-hole SXR camera assembled with Image-intensified charged coupled device (ICCD). The SXR experimental images have been compared with calculated tangential images using model profiles for emissivity to identify the plausible SXR emissivity profile. It has been found that a model profile of helical core having SXR emissivity 2--4 times higher than the background provides 2D SXR images in reasonable agreement with the experimental results. Time evolution of the SXR emissivity profile measured with a photodiode array has shown that the emissivity is the highest in the core region with a quasi-periodic oscillation of the peak position.

Onchi, Takumi; Ikezoe, Ryuya; Oki, Kensuke; Sanpei, Akio; Himura, Haruhiko; Masamune, Sadao; Nishino, Nobuhiro; Koguchi, Haruhisa



Backscatter factors and mass energy-absorption coefficient ratios for diagnostic radiology dosimetry  

NASA Astrophysics Data System (ADS)

Backscatter factors, B, and mass energy-absorption coefficient ratios, (?en/?)w, air, for the determination of the surface dose in diagnostic radiology were calculated using Monte Carlo simulations. The main purpose was to extend the range of available data to qualities used in modern x-ray techniques, particularly for interventional radiology. A comprehensive database for mono-energetic photons between 4 and 150 keV and different field sizes was created for a 15 cm thick water phantom. Backscattered spectra were calculated with the PENELOPE Monte Carlo system, scoring track-length fluence differential in energy with negligible statistical uncertainty; using the Monte Carlo computed spectra, B factors and (?en/?)w, air were then calculated numerically for each energy. Weighted averaging procedures were subsequently used to convolve incident clinical spectra with mono-energetic data. The method was benchmarked against full Monte Carlo calculations of incident clinical spectra obtaining differences within 0.3-0.6%. The technique used enables the calculation of B and (?en/?)w, air for any incident spectrum without further time-consuming Monte Carlo simulations. The adequacy of the extended dosimetry data to a broader range of clinical qualities than those currently available, while keeping consistency with existing data, was confirmed through detailed comparisons. Mono-energetic and spectra-averaged values were compared with published data, including those in ICRU Report 74 and IAEA TRS-457, finding average differences of 0.6%. Results are provided in comprehensive tables appropriated for clinical use. Additional qualities can easily be calculated using a designed GUI interface in conjunction with software to generate incident photon spectra.

Benmakhlouf, Hamza; Bouchard, Hugo; Fransson, Annette; Andreo, Pedro



Backscatter factors and mass energy-absorption coefficient ratios for diagnostic radiology dosimetry.  


Backscatter factors, B, and mass energy-absorption coefficient ratios, (?(en)/?)(w, air), for the determination of the surface dose in diagnostic radiology were calculated using Monte Carlo simulations. The main purpose was to extend the range of available data to qualities used in modern x-ray techniques, particularly for interventional radiology. A comprehensive database for mono-energetic photons between 4 and 150 keV and different field sizes was created for a 15 cm thick water phantom. Backscattered spectra were calculated with the PENELOPE Monte Carlo system, scoring track-length fluence differential in energy with negligible statistical uncertainty; using the Monte Carlo computed spectra, B factors and (?(en)/?)(w, air) were then calculated numerically for each energy. Weighted averaging procedures were subsequently used to convolve incident clinical spectra with mono-energetic data. The method was benchmarked against full Monte Carlo calculations of incident clinical spectra obtaining differences within 0.3-0.6%. The technique used enables the calculation of B and (?(en)/?)(w, air) for any incident spectrum without further time-consuming Monte Carlo simulations. The adequacy of the extended dosimetry data to a broader range of clinical qualities than those currently available, while keeping consistency with existing data, was confirmed through detailed comparisons. Mono-energetic and spectra-averaged values were compared with published data, including those in ICRU Report 74 and IAEA TRS-457, finding average differences of 0.6%. Results are provided in comprehensive tables appropriated for clinical use. Additional qualities can easily be calculated using a designed GUI interface in conjunction with software to generate incident photon spectra. PMID:22024474

Benmakhlouf, Hamza; Bouchard, Hugo; Fransson, Annette; Andreo, Pedro



Time trends in the levels and patterns of polycyclic aromatic hydrocarbons (PAHs) in pine bark, litter, and soil after a forest fire.  


Forest fires are known as an important natural source of polycyclic aromatic hydrocarbons (PAHs), but time trends of PAH levels and patterns in various environmental compartments after forest fires have not been thoroughly studied yet. In this study, 16 US-EPA priority PAHs were analyzed for pine bark, litter, and soil samples collected one, three, five, and seven months after a forest fire in Pohang, South Korea. At the first sampling event, the highest levels of ?16 PAHs were measured for the three types of samples (pine bark: 5,920 ng/g, litter: 1,540 ng/g, and soil: 133 ng/g). Thereafter, there were apparent decreasing trends in PAH levels; the control samples showed the lowest levels (pine bark: 124 ng/g, litter: 75 ng/g, and soil: 26 ng/g). The levels of PAHs in the litter and soil samples normalized by organic carbon (OC) fractions also showed decreasing trends, indicating a direct influence of the forest fire. Among the 16 target PAHs, naphthalene was a dominant compound for all types of samples. Light PAHs with 2-4 rings significantly contributed to the total concentration, and their contribution decreased in the course of time. Runoff by heavy precipitation, evaporation, and degradation of PAHs in the summer were probably the main reasons for the observed time trends. The results of principal component analysis (PCA) and diagnostic ratio also supported that the forest fire was indeed an important source of PAHs in the study area. PMID:23972323

Choi, Sung-Deuk



Using comprehensive GC?×?GC to study PAHs and n-alkanes associated with PM2.5 in urban atmosphere.  


Comprehensive two-dimensional gas chromatography (GC?×?GC) utilizing a flow modulator was applied to study particulate polycyclic aromatic hydrocarbons (PAHs) and n-alkanes in the urban atmosphere. Samples were collected onto quartz fiber filters using a PM2.5 sampler at Megacity Shanghai, China. Sample preparation included extraction into n-hexane-dichloromethane mixture and cleanup on silver-impregnated silica column. Analyses were performed well with GC?×?GC-FID and GC?×?GC-TOFMS equipment. Average particulate PAHs and n-alkane concentrations were in the range of 40-100 ng/m(3) and 120-500 pg/m(3), respectively. It is alarming to note that PAHs and n-alkane concentrations were increasing with urban PM2.5 values and exceeded the air quality standards in many sampling events. Among them, 2-ring, 3-ring, and 4-ring PAHs accounted for the majority of total PAHs, and C10-15 accounted for the majority of particulate n-alkanes. Potential sources of PAHs in PM2.5 were identified using the diagnostic ratios between PAHs. Local emission sources such as combustion from gasoline and diesel engines were the main contributors of particulate-associated PAHs, while long-range transport had minor contribution to the particulate PAHs. Additionally, we determined the overall carcinogenicity of the samples based on PAH concentrations by a dose addition model and found that the overall carcinogenicity during polluted period was obviously higher than during good air quality period. PMID:25345921

Xu, Tingting; Lv, Yan; Cheng, Tiantao; Li, Xiang



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)

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.

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



PAHs in decaying Quercus ilex leaf litter: mutual effects on litter decomposition and PAH dynamics.  


The investigation of the relationships between litter decomposition and polycyclic aromatic hydrocarbons (PAHs) is important to shed light not only on the effects of these pollutants on fundamental ecosystem processes, such as litter decomposition, but also on the degradation of these pollutants by soil microbial community. This allows to understand the effect of atmospheric PAH contamination on soil PAH content via litterfall. At this aim, we studied mass and PAH dynamics of Quercus ilex leaf litters collected from urban, industrial and remote sites, incubated in mesocosms under controlled conditions for 361d. The results highlighted a litter decomposition rate of leaves sampled in urban>industrial>remote sites; the faster decomposition of litter of the urban site is also related to the low C/N ratio of the leaves. The PAHs showed concentrations at the beginning of the incubation of 887, 650 and 143 ng g(-1)d.w., respectively in leaf litters from urban, industrial and remote sites. The PAHs in litter decreased along the time, with the same trend observed for mass litter, showing the highest decrease at 361 d for the urban leaf litter. Anyway, PAH dynamics in all the litters exhibited two phases of loss, separated by a PAH increase observed at 246 d and mainly linked to benzo[e]pyrene. PMID:25113181

De Nicola, F; Baldantoni, D; Alfani, A



Aryl hydrocarbon receptor mediated activities in road dust from a metropolitan area, Hanoi-Vietnam: contribution of polycyclic aromatic hydrocarbons (PAHs) and human risk assessment.  


Dioxin-Responsive Chemical-Activated LUciferase gene eXpression assay (DR-CALUX) was applied to assess the total toxic activity of the mixture of PAHs and related compounds as well as dioxin-related compounds in road dust from urban areas of Hanoi, Vietnam. Road dust from Hanoi contained significantly higher DR-CALUX activities (3 to 39, mean 20 ng CALUX-TEQ/g dw) than those from a rural site (2 to 13, mean 5 ng CALUX-TEQ/g dw). The total concentrations of 24 major PAHs (?24PAHs) in urban road dust (0.1 to 5.5, mean 2.5 ?g/g dw) were also 6 times higher than those in rural road dust (0.08 to 1.5, mean 0.4 ?g/g dw). Diagnostic ratios of PAHs indicated vehicular engine combustion as the major PAH emission source in both sites. PAHs accounted for 0.8 to 60% (mean 10%) and 2 to 76% (mean 20%) of the measured CALUX-TEQs in road dust for Hanoi the rural site, respectively. Benzo[b]-/benzo[k]fluoranthenes were the major TEQ contributors among PAHs, whereas DRCs contributed <0.1% to CALUX-TEQs for both rural and urban sites. These results suggest TEQ contribution of other aryl hydrocarbon receptor agonists in road dust. Significant PAH concentrations in urban dust indicated high mutagenic and carcinogenic potencies. Estimated results of incremental life time cancer risk (ILCR) indicated that Vietnamese populations, especially those in urban areas such as Hanoi, are potentially exposed to high cancer risk via both dust ingestion and dermal contact. This is the first study on the exposure risk of AhR agonists, including PAHs and DRCs, in urban road dust from a developing country using a combined bio-chemical analytical approach. PMID:24522011

Tuyen, Le Huu; Tue, Nguyen Minh; Suzuki, Go; Misaki, Kentaro; Viet, Pham Hung; Takahashi, Shin; Tanabe, Shinsuke



Conversion of the 6302 / 6301 Stokes V Line Ratio to the 5250 / 5247 Ratio for the Diagnostics of Quiet-Sun Magnetic Fields  

NASA Astrophysics Data System (ADS)

Observations in the "green" spectral lines Fe I 5247.06 and 5250.22 Å and in the "red" lines Fe I 6301.50 and 6302.50 Å are widely used to explore the properties of solar magnetic fields. The green line pair was introduced in 1973 as part of the line-ratio technique, which has been a powerful tool for investigations of intrinsic magnetic field properties at spatially unresolved scales (magnetic flux tubes with kG strengths). The red line pair has recently played a major role for magnetic-field diagnostics due to the large amount of high-quality data provided by the Hinode space observatory. These red lines however differ not only in the values of their Landé factors, but also in their line-formation properties, with the consequence that the magnetic-field information in their line ratio gets tangled up with thermodynamic effects. In contrast, as the green Fe I 5247.06 and 5250.22 Å lines differ only in their Landé factors, the magnetic field effects become cleanly separated from the thermodynamics, which allows the intrinsic magnetic field parameters to be extracted without ambiguties. The red and green line-ratio values are however statistically correlated. By determining the statistical regression function that relates them, it becomes possible to convert the "contaminated" and ambiguous red line ratio into the green line ratio, with which a reliable direct interpretation in terms of intrinsic field strengths is possible. To determine how the two line ratios are related we have made Stokesmeter observations in these four spectral lines with two solar instruments equipped with high-precision spectropolarimeters, ZIMPOL-3 at IRSOL (Locarno, Switzerland), and the STOP telescope at the Sayan Solar Observatory (Irkutsk, Russia). Most of the obtained results are based on IRSOL observations of quiet-sun magnetic fields. In the case of STOP the full-disk magnetograms of large-scale solar magnetic fields are analyzed. A major advantage at IRSOL is the possibility to observe the green and red line pairs simultaneously on the same CCD chip. We have determined how the two line ratios decrease with increasing Stokes V amplitude and increase with increasing distance from disk center. The relation that allows us to convert the observed values for the red line ratio into the corresponding values for the green line ratio has been found and given in analytical form.

Demidov, M. L.; Stenflo, J. O.; Bianda, M.; Ramelli, R.



Limitations of the Odds Ratio in Gauging the Performance of a Diagnostic, Prognostic, or Screening Marker  

Microsoft Academic Search

A marker strongly associated with outcome (or disease) is often assumed to be effective for classifying persons according to their current or future outcome. However, for this assumption to be true, the associated odds ratio must be of a magnitude rarely seen in epidemiologic studies. In this paper, an illustration of the relation between odds ratios and receiver operating characteristic

Margaret Sullivan Pepe; Holly Janes; Gary Longton; Wendy Leisenring; Polly Newcomb



Spatial and temporal variation of freely dissolved PAHs in an urban river undergoing Superfund remediation  

PubMed Central

Urban rivers with a history of industrial use can exhibit spatial and temporal variations in contaminant concentrations that may significantly affect risk evaluations and even the assessment of remediation efforts. Concentrations of 15 biologically available priority pollutant polycyclic aromatic hydrocarbons (PAHs) were measured over five years along 18.5 miles of the lower Willamette River using passive sampling devices and HPLC. The study area includes the Portland Harbor Superfund megasite with several PAH sources including remediation operations for coal tar at RM 6.3 west and an additional Superfund site, McCormick and Baxter, at RM 7 east consisting largely of creosote contamination. Study results show that organoclay capping at the McCormick and Baxter Superfund Site reduced PAHs from a pre-cap average of 440 ± 422 ng/L to 8 ± 3 ng/L post-capping. Results also reveal that dredging of submerged coal tar nearly tripled nearby freely dissolved PAH concentrations. For apportioning sources, fluoranthene/ pyrene and phenanthrene/anthracene diagnostic ratios from passive sampling devices were established for creosote and coal tar contamination and compared to published sediment values. PMID:19174872

Sower, GJ; Anderson, K.A.



Occurrence, distribution, sources and toxic potential of polycyclic aromatic hydrocarbons (PAHs) in surface soils from the Kumasi Metropolis, Ghana.  


As a developing country, the economic and population growth rates in Ghana over the past few years have seen a tremendous increase. The growing rate of industrialization is gradually leading to contamination and deterioration of the environment and pollution is likely to reach disturbing levels. Surface soil samples were collected randomly from 36 communities in the Kumasi Metropolis, Ghana, to determine the concentrations, distribution, sources and toxic potential of emission of polycyclic aromatic hydrocarbons (PAHs) since no such comprehensive study had been conducted. The mean concentration of total PAHs in the surface soils in each community ranged from 14.78 at Ahinsan to 2084 ng/g dry weight at Adum with an average of 442.5 ± 527.2 ng/g dry weight. Diagnostic ratios and chemical mass balance models of the results showed that PAHs in surface soil samples from the study area were mainly from fuel combustion. Carcinogenic potency of PAH load from the city centre was approximately 150 times higher as compared to a pristine site, Kwame Nkrumah University of Science and Technology's Botanical Garden. BaP, a human carcinogen, contributed 70% of the total PAHs toxicity level from the city centre of Kumasi. PMID:25108249

Bortey-Sam, Nesta; Ikenaka, Yoshinori; Nakayama, Shouta M M; Akoto, Osei; Yohannes, Yared Beyene; Baidoo, Elvis; Mizukawa, Hazuki; Ishizuka, Mayumi



PAH-profiles in sediment cores from the Baltic Sea.  


To document the historical input the PAH-profiles of sediment cores in two different basins of the Baltic Sea, the Gotland Basin (GB) and Arkona Basin (AB), were analysed by means of GC-MS. 35 PAHs were quantified in all samples, and additionally, several marker PAHs, like Cyclopenta[cd]phenanthrene (CCP) for combustion processes and retene for terrigenous input, were quantified in selected samples. The preindustrial sediments (older than 200-250 years) in the GB core illustrate concentrations <100 ng PAH15 g(-1) d.w. Calculated PAH-ratios indicated combustion processes as the main sources for both basins. The Perylene concentrations within the sediment cores decrease with increasing depth, along with an increase in relative percentage, indicating slow diagenetic processes. The preservation and enrichment of the introduced PAHs was more pronounced in the GB core. PMID:12146840

Ricking, M; Schulz, H M



Diagnostics of the molecular component of photon-dominated regions with mechanical heating. II. Line intensities and ratios  

NASA Astrophysics Data System (ADS)

CO observations in active galactic nuclei and starbursts reveal high kinetic temperatures. Those environments are thought to be very turbulent due to dynamic phenomena, such as outflows and high supernova rates. We investigate the effect of mechanical heating on atomic fine-structure and molecular lines and on their ratios. We try to use those ratios as a diagnostic to constrain the amount of mechanical heating in an object and also study its significance on estimating the H2 mass. Equilibrium photodissociation models (PDRs hereafter) were used to compute the thermal and chemical balance for the clouds. The equilibria were solved for numerically using the optimized version of the Leiden PDR-XDR code. Large velocity-gradient calculations were done as post-processing on the output of the PDR models using RADEX. High-J CO line ratios are very sensitive to mechanical heating (?mech hereafter). These emission becomes at least one order of magnitude brighter in clouds with n ~ 105 cm-3 and a star formation rate of 1 M? yr-1 (corresponding to ?mech = 2 × 10-19 erg cm-3 s-1). The emission of low-J CO lines is not as sensitive to ?mech, but they do become brighter in response to ?mech. Generally, for all of the lines we considered, ?mech increases excitation temperatures and decreases the optical depth at the line centre. Hence line ratios are also affected, strongly in some cases. Ratios involving HCN are a good diagnostic for ?mech, where the HCN(1-0)/CO(1-0) increases from 0.06 to 0.25, and the HCN(1-0)/HCO+(1-0) increase from 0.15 to 0.5 for amounts of ?mech that are equivalent to 5% of the surface heating rate. Both ratios increase to more than 1 for higher ?mech, as opposed to being much less than unity in pure PDRs. The first major conclusion is that low-J to high-J intensity ratios will yield a good estimate of the mechanical heating rate (as opposed to only low-J ratios). The second one is that the mechanical heating rate should be taken into account when determing AV or, equivalently, NH, and consequently the cloud mass. Ignoring ?mech will also lead to large errors in density and radiation field estimates. Appendices are available in electronic form at http://www.aanda.orgThe data used to generate all the grids are only available at the CDS via anonymous ftp to ( or via

Kazandjian, M. V.; Meijerink, R.; Pelupessy, I.; Israel, F. P.; Spaans, M.



Occurrence and source apportionment of PAHs in highly vulnerable karst system.  


The concentration and spatial distribution of polycyclic aromatic hydrocarbons (PAHs) in topsoil, groundwater and groundwater suspended solids (SS) at Guozhuang karst water system of northern China were investigated. The total concentration of PAHs ranged from 622 to 87,880 ng/g dry weight in topsoil, from 4739 to 59,314 ng/g dry weight in SS, and from 2137 to 9037 ng/L in groundwater, with mean values of 17,174 ng/g, 11,990 ng/g and 5020 ng/L, respectively. High concentrations of PAHs were mainly observed in the coal mining industrial area and the discharge area. The composition of PAHs indicated that low molecular weight PAHs were predominant in groundwater samples, the content of medium molecular weight PAHs was elevated in SS, and carcinogenic high molecular weight PAHs were frequently detected in topsoil. The high contents of low-medium molecular weight PAHs in groundwater and SS suggested relatively recent local sources of PAHs that were transported into the aquifer via leakage of contaminated surface water and/or infiltration of PAH-containing precipitation. The results of evaluating sources of PAHs using ratios of specific PAH compounds showed that PAHs mainly originated from coal and wood combustion. Furthermore, five sources were identified by positive matrix factorization (PMF) model, and the contribution to the total loadings of groundwater PAHs were: 2% for unburnt oil, 32% for coal combustion, 22% for vehicle emission, 27% for biomass combustion and 18% for coke production, respectively. Furthermore, strong correlations of total PAHs with total organic carbon (TOC) in topsoil indicated co-emission of PAHs and TOC. Poor correlations of PAHs with dissolved organic carbon (DOC) in groundwater indicated that other factors exert stronger influences. Therefore, PAHs might have posed a major threat to the quality of potable groundwater in Guozhuang karst water system. PMID:24852613

Shao, Yixian; Wang, Yanxin; Xu, Xiaoqing; Wu, Xiao; Jiang, Zhou; He, Shanshan; Qian, Kun



Possible evidence of destroying small PAH particles by radiation from AGNs  

NASA Astrophysics Data System (ADS)

The issue of destroying small polycyclic aromatic hydrocarbon (PAH) particles by radiation from AGNs is examined through optical narrow-emission line ratios of a sample of type II AGNs. We find that narrow-line ratios [OI]?6300/H? and [SII]?6716, ?6731/H? have prominent correlations with the PAH 11.3/7.7 ratio in our selected sample of AGNs. Because of the marginal (and in some cases no) dependence of the PAH ratio on the gas metallicity, a possible explanation for the correlations is the destruction of small PAH particles by the hard ionizing field associated with the AGNs.

Feng, Qi-Chen; Wang, Jing; Wei, Jian-Yan



Neutron spectroscopy as a fuel ion ratio diagnostic: Lessons from JET and prospects for ITER  

SciTech Connect

The determination of the fuel ion ratio n{sub t}/n{sub d} in ITER is required at a precision of 20%, time resolution of 100 ms, spatial resolution of a/10, and over a range of 0.016 keV and for n{sub T}/n{sub D}<0.6. A crucial issue is the signal-to-background situation in the measurement of the weak 2.5 MeV emission from DD reactions in the presence of a background of scattered 14 MeV DT neutrons. Important experimental input and corroboration for this assessment are presented from the time-of-flight neutron spectrometer at JET where the presence of a strong component of backscattered neutrons is observed. Neutron emission components on ITER due to beam-thermal and tritium-tritium reactions can further enhance the prospects for NES.

Ericsson, G.; Conroy, S.; Gatu Johnson, M.; Andersson Sunden, E.; Cecconello, M.; Eriksson, J.; Hellesen, C.; Sangaroon, S.; Weiszflog, M. [Department of Physics and Astronomy, Uppsala University (EURATOM-VR Association), SE-75120 Uppsala (Sweden); Collaboration: JET EFDA Contributors



Laboratory Spectroscopy of PAHs  

NASA Astrophysics Data System (ADS)

Spectroscopic investigations of PAHs have been conducted for many years, commencing with solid and solution studies and more recently including gas phase characterisation of a broad range of different species. Through the development of new, efficient methods of production and more sensitive spectroscopic techniques, fresh data are becoming available for not only neutral species, but also for radicals, ions and clusters.

Pino, T.; Féraud, G.; Bréchignac, Ph.; Bieske, E. J.; Schmidt, T. W.



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


The common gas chromatography/mass spectrometry (GC/MS) approaches such as selective ion monitoring (SIM) or single ion extraction (SIE) from full scan data produce the error (over- or underestimation) estimates for the high level alkylated polycyclic aromatic hydrocarbons (PAHs). In order to rectify the error, the alkylated PAHs in the crude oil samples are quantified by deeply investigating the existing full scan data of 1D GC/MS, instead of resuming with the complex and inaccessible equipments (multidimensional gas chromatography or mass spectrometry). The aim of this study is to provide the detailed qualitative and quantitative basis data (confirming ions, relative abundance, retention indices, and area counts) of the high level alkylated PAHs by a comprehensive three-step method: (1) the potential confirming ions per isomer are selected by exploring the multiple fragment patterns formation mechanism; (2) the reasonable confirming ions are estimated by comparing extracted ion chromatography (EIC) of the potential confirming ions; (3) after deconvolution, composite chromatograms of the reasonable confirming ions illustrate the basis data by assigning peaks for target PAHs definitively. The validation data, resulting concentrations and diagnostic ratios for each homolog are compared with those obtained from SIM. The experimental data demonstrate that significant inaccurate identifications and concentration estimates are obtained when SIM mode is used for C4 Naphthalene (C4 N), C3 Phenanthrene (C3 P), C4 Phenanthrene (C4 P), C3 Dibenzothiophene (C3 D), C3 Fluorene (C3 F), C2-4 Chrysene (C2-4 C) and C1 Fluoranthene (C1 Flt). This study evaluates the usefulness of the previous fragmentation patterns, and confirms compound presence by GC/MS using the different spectral deconvolution software. This approach is developed as a broad screen for environmental samples (including petrol, diesel fuel and coal tar), with only the crude oil results being presented here. PMID:24229786

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



Environmental aspects of PAH biodegradation.  


Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants, some of which are on the US Environmental Protection Agency priority pollutant list. Consequently, timely clean-up of contaminated sites is important. The lower-mol-wt PAHs are amenable to bioremediation; however, higher-mol-wt PAHs seem to be recalcitrant to microbial degradation. The rates of biodegradation of PAHs are highly variable and are dependent not only on PAH structure, but also on the physicochemical parameters of the site as well as the number and types of microorganisms present. PAHs sorb to organic matter in soils and sediments, and the rate of their desorption strongly influences the rate at which microorganisms can degrade the pollutants. Much of the current PAH research focuses on techniques to enhance the bioavailability and, therefore, the degradation rates of PAHs at polluted sites. Degradation products of PAHs are, however, not necessarily less toxic than the parent compounds. Therefore, toxicity assays need to be incorporated into the procedures used to monitor the effectiveness of PAH bioremediation. In addition, this article highlights areas of PAH research that require further investigation. PMID:7486983

Shuttleworth, K L; Cerniglia, C E



Assessing risks to adults and preschool children posed by PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) during a biomass burning episode in Northern Thailand.  


To investigate the potential cancer risk resulting from biomass burning, polycyclic aromatic hydrocarbons (PAHs) bound to fine particles (PM2.5) were assessed in nine administrative northern provinces (NNP) of Thailand, before (N-I) and after (N-II) a haze episode. The average values of ?3,4-ring PAHs and B[a]PEquivalent concentrations in world urban cities were significantly (p<0.05) much higher than those in samples collected from northern provinces during both sampling periods. Application of diagnostic binary ratios of PAHs underlined the predominant contribution of vehicular exhaust to PM2.5-bound PAH levels in NNP areas, even in the middle of the agricultural waste burning period. The proximity of N-I and N-II values in three-dimensional (3D) principal component analysis (PCA) plots also supports this conclusion. Although the excess cancer risk in NNP areas is much lower than those of other urban area and industrialized cities, there are nevertheless some concerns relating to adverse health impacts on preschool children due to non-dietary exposure to PAHs in home environments. PMID:25506906

Pongpiachan, Siwatt; Tipmanee, Danai; Khumsup, Chukkapong; Kittikoon, Itthipon; Hirunyatrakul, Phoosak



Line Ratio Diagnostics Along the Disc of Two Edge-on Lenticular Galaxies, NGC 4710 and NGC 5866  

NASA Astrophysics Data System (ADS)

We present interferometric observations of a multitude of CO lines and dense gas tracers in two nearby edge-on lenticular galaxies, NGC~4710 and NGC~5866. 12CO(1-0), 12CO(2-1), 13CO(1-0), 13CO(2-1), HCN(1-0), HCO+(1-0), HNC(1-0) ad HNCO(4-3) were detected in both galaxies. The detections of HNC(1-0) and HNCO(4-3) are presenting here for the first time in these early-types. Our observations reveal that the CO gas is much more extended compared with the dense gas tracers which are generally centrally concentrated except HCN(1-0) which was also detected in the outskirts of NGC~5866. The unique X-shape (two-component velocity distributions indicating nuclear disc and inner ring) position-velocity diagram (PVD) of these barred edge-on galaxies allows us to study integrated line intensity ratios as a function projected radius along the velocity components. We study the gas physical conditions of two-component molecular ISM, i.e. one traced by CO and one traced by HCN, HCO+, HNC and HNCO, in each velocity component separately seen on the PVD by performing line ratio diagnostics in three complementary ways. In the nuclear disc, the CO gas is gravitationally unstable, optically thinner, hotter and dense gas fraction is higher, while in the inner ring the gas is more settled, optically thick, colder and the dense gas fraction is lower. We also compare the line ratios to that obtained in the nucleus of other lenticular, spiral, seyfert, starburst and peculiar galaxies as well as that obtained in the GMCs of some other spirals/starbursts. We found that the gas in the nuclear discs of NGC~4710 and NGC~5866 has line ratios similar to that in the center of starburst galaxies while the gas in the inner rings show some differences. We finally perform non-LTE radiative transfer code to the two-component ISM using a multitude of tracers. The model results, which are agree with the empirical results, indicate that there is a factor of 2 difference in the density of the gas traced by CO and the one traced by high density tracers in the nuclear disc but average kinetic temperature is similar, while the gas in the inner ring is relatively colder and less dense compared with the gas in the nuclear disc.

Topal, Selcuk



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

NASA Astrophysics Data System (ADS)

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 11.0?g/g (dry weight) in the core from the Huangpu River, Shanghai. The second highest concentration of PAHs was 4.42?g/g (dry weight) in surface sediment of Victoria Harbour in Hong Kong, and 5.73?g/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 0.30?g/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.

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



Biodegradation and adsorption of C1- and C2-phenanthrenes and C1- and C2-dibenzothiophenes in the presence of clay minerals: effect on forensic diagnostic ratios.  


The impact of modified montmorillonites on adsorption and biodegradation of crude oil C1-phenanthrenes, C1-dibenzothiophenes, C2-phenanthrenes and C2-dibenzothiophenes was investigated in aqueous clay/oil microcosm experiments with a hydrocarbon degrading microorganism community. Consequently, the effect on C1-dibenzothiophenes/C1-phenanthrenes, C2-dibenzothiophenes/C2-phenanthrenes, 2+3-methyldibenzothiophene/4-methyldibenzothiophene and 1-methyldibenzothiophene/4-methyldibenzothiophene ratios commonly used as diagnostic ratios for oil forensic studies was evaluated. The clay mineral samples were treated to produce acid activated montmorillonite, organomontmorillonite and homoionic montmorillonite which were used in this study. The different clay minerals (modified and unmodified) showed varied degrees of biodegradation and adsorption of the C1-phenanthrenes, C1-dibenzothiophenes, C2-phenanthrenes and C2-dibenzothiophenes. The study indicated that as opposed to biodegradation, adsorption has no effect on the diagnostic ratios. Among the diagnostic ratios reviewed, only C2-dibenzothiophenes/C2-phenanthrenes ratio was neither affected by adsorption nor biodegradation making this ratio very useful in forensic studies of oil spills and oil-oil correlation. PMID:24275986

Ugochukwu, Uzochukwu C; Head, Ian M; Manning, David A C



PAHs in Comets: An Overview  

E-print Network

Polycyclic aromatic hydrocarbon (PAH) molecules, ubiquitously seen in the interstellar medium (ISM) of our own and external galaxies, might have been incorporated into comets if they are formed from relatively unprocessed interstellar matter. The detection of PAHs in comets would be an important link between the ISM and comets. This review compiles our current knowledge on cometary PAHs, based on ground-based and space-borne observations of infrared vibrational and ultraviolet fluorescence spectra of comets, and laboratory analysis of interplanetary dust particles possibly of cometary origin and cometary samples returned to Earth by the Stardust spacecraft. The latter provided the most unambiguous evidence for the presence of PAHs in cometary nuclei.

Aigen Li



The distribution and origin of PAHs over the Asian marginal seas, the Indian, and the Pacific Oceans: Implications for outflows from Asia and Africa  

NASA Astrophysics Data System (ADS)

samples were collected aboard the R/V Dayang Yihao from 8 January to 7 August 2007 to investigate the geographical distribution of polycyclic aromatic hydrocarbons (PAHs) over oceans and to assess their continental origins. The highest concentrations were found over the marginal seas in Asia, especially the East and South China Seas, indicating that China is a top source of emissions into the marine atmosphere in the areas monitored on this cruise. PAH concentrations over the west oceanic region in the South Indian Ocean were noticeably higher than in other areas of the Indian Ocean, most likely because air masses from Africa, the Arabian Sea, and the Bay of Bengal exert a negative impact on those regions through long-range atmospheric transport. The PAH isomer ratio values varied over the oceans that were impacted by continental sources but remained relatively uniform over most of the remote oceans. Using diagnostic ratio analysis, we found PAHs emitted from China were mainly associated with biomass/coal burning. The measurements of levoglucosan were consistent with the results mentioned above. The western part of the South Indian Ocean atmosphere was likely affected by wildfire emissions from Africa, while the northern part was by petroleum combustion, biofuel, and wildfire burning, because the winter monsoon most likely carries aerosol from the Arabian Peninsula and India across the equator. Using the monthly images of fire activity and aerosol optical depth, it can be confirmed biomass burning from Africa can significantly influence the aerosol over the Indian Ocean.

Liu, Junwen; Xu, Yue; Li, Jun; Liu, Di; Tian, Chongguo; Chaemfa, Chakra; Zhang, Gan



PAHs in PM2.5 in Zhengzhou: concentration, carcinogenic risk analysis, and source apportionment.  


Ambient air samples were collected at two different locations between 2011 and 2012 in Zhengzhou, China in order to assess the concentration level, health risks, as well as the sources of polycyclic aromatic hydrocarbons (PAHs) in particulate matter (PM2.5). The mean annual levels of PM2.5 observed at industry site and residential site were 172?±?121 and 160?±?72 ?g m(-3), respectively, which were about five times the annual value of proposed PM2.5 standard (35 ?g m(-3)) in China. The PM2.5 in all daily samples (n?=?47) exceeds the proposed PM2.5 standard in China (75 ?g m(-3)) at both industrial and residential sites. Seasonal variations of PM2.5 showed a clear trend of winter?>?autumn?>?spring?>?summer at both sites. The total concentrations of 16 PM2.5-associated PAHs ranged from 61?±?51 to 431?±?281 and 38?±?25 to 254?±?189 ng m(-3), with mean value of 176?±?233 and 111?±?146 ng m(-3) at industry and residential sites, respectively. The major species were fluoranthene, pyrene, chrysene, benzo[b]fluoranthene and benzo[k]fluoranthene, and the concentration levels of PAHs in PM2.5 were higher in winter than those of other seasons at both sites. The annual mean values of toxicity equivalency concentrations of ?16PAHs in PM2.5 were 22.8 and 13.5 ng m(-3) in industry and residential area, respectively. In this study, the risk level of adult citizens through inhalation exposure to PAHs was calculated. The average estimates of lifetime inhalation cancer risks were approximately 8.9?×?10(-7) and 6.3?×?10(-7) for industry and residential sites, respectively. The main sources of 16 PAHs from both diagnostic ratios and principle component analysis identified as vehicular emissions and coal combustion. PMID:25060861

Wang, Jia; Geng, Ning Bo; Xu, Yi Fei; Zhang, Wen Ding; Tang, Xiao Yan; Zhang, Rui Qin



Compound Specific Radiocarbon Analysis (CSRA) Of Polycyclic Aromatic Hydrocarbons(PAHs) in Fine Organic Aerosols From Residential Area Of Suburb Tokyo  

NASA Astrophysics Data System (ADS)

Atmospheric polycyclic aromatic hydrocarbons (PAHs) originate mostly from incomplete combustion of carbon-based fuels. Amongst atmospheric contaminants, PAHs account for most (35-82 percent) of the total mutagenic activity of ambient aerosols. Hence, reduction of air pollution by PAHs is essential for an effective air quality control, which requires reliable source apportionment. Recently developed preparative capillary GC system and microscale 14C analysis made CSRA applicable to environmental samples. The 5730 yr half-life of 14C makes it an ideal tracer for identifying combustion products derived from fossil fuels (14C-free) vs. those from modern biomass (contemporary 14C). In the present study we performed radiocarbon analysis of PAHs in fine particulate aerosols (PM10 and PM1.1) from a residential area in suburb Tokyo, to apportion their origin between fossil and biomass combustion. Acquisition of source information for size segregated aerosols (i.e., PM1.1) from 14C measurement was of special interest as particles with diameter of 1?m or less are known to be able to remain suspended in air for weeks and penetrate into the deepest part of the respiratory system. Total PAHs concentrations (sum of 38 compounds with 3-6 aromatic rings) ranged 0.94-3.25 ng/m3 for PM10 and 0.69-2.68 ng/m3 for PM1.1 samples. Observation of relatively small amount of retene (0.2-0.4 percent of total PAHs) indicates some contribution from wood (Gymnosperm) combustion. Diagnostic isomer pair ratios of PAHs (i.e., 1,7-/2,6-dimethylphenanthrene, fluoranthene/pyrene and indeno [1,2,3-cd]pyrene/benzo[ghi]perylene) indicated mixed contributions both from petroleum and wood/coal combustion sources. Also the ratios implied that the latter source become relatively important in winter than the rest of the year for both PM10 and PM1.1 samples, which coincides with seasonal trend of retene proportion. The source information obtained from 14C analyses will be compared and discussed against that from diagnostic isomer pair ratios.

Kumata, H.; Uchida, M.; Sakuma, E.; Fujiwara, K.; Yoneda, M.; Shibata, Y.



Isotopic Differences Between PAH Isomers in Murchison  

NASA Astrophysics Data System (ADS)

Previous studies using compound-specific isotope analysis of aromatic fractions from the Orgueil and Murchison carbonaceous chondrites suggested that there may be variations in delta^13C values between different PAH (1). Although the Orgueil meteorite was found to be too heavily contaminated with terrestrial PAH to be of any value, strong evidence that the PAH in Murchison were indigenous came from their relatively heavy isotope compositions of between -8 and -11o/oo. Aromatic fractions were isolated from two new samples of Murchison using solvent extraction followed by column chromatography on silica gel. The compounds were tentantively identified using GCMS and positive confirmation obtained for some by running authentic standards. The carbon isotope compositions of individual PAH were measured by isotope ratio monitoring-GCMS (irm-GCMS) on a Finnigan-MAT Delta S/GC. The most striking feature in the distribution of PAH in Murchison is the overwhelming predominace of phenanthrene, fluoranthene, and pyrene, with the latter two compounds being the most abundant. Anthracene is present at about 50 times less than phenanthrene with most other higher molecular weight PAH present in similar or smaller quantities. The isotopic compositions of parental PAH (no side chains) are listed in the table. The carbon isotope compositions range from -6 to -22o/oo. The range is similar to the isotopic compositions observed in stepped combustion of Murchison macromolecular material where the bulk delta^13C is -17o/oo. In general the higher molecular weight PAH appear to be isotopically lighter; however, at first sight there is no systematic trend. For instance both phenanthrene and fluorathene have similar delta^13C values, as do pyrene and benzo(j)fluoranthene. However, there are apparently systematic differences between some isomers; for example, anthracene is 6.5o/oo heavier that phenanthrene, fluoranthene is 7o/oo heavier than pyrene, and benzo(j)fluoranthene is 7o/oo heavier than benzo(e)pyrene. A decrease in delta^13C with increasing number of aromatic rings would be consistent with an origin for the higher homologues by condensation reactions with each closure of a benzene ring resulting in a step down in delta^13C, assuming a kinetic isotope effect during the condensation reaction. The differences in isotope composition of PAH in Murchison may represent two distinct populations synthesized at different locations, e.g., on the parent body vs. in the solar nebula. The systematic difference of 7o/oo between isomers may provide one clue. Addition of benzene rings to fluoranthene and pyrene, the most abundant PAH, from a common source would preserve an isotopic difference between isomers containing a S-membered ring and those without as is seen with benzo(e)pyrene and benzo(j)fluoranthene. Compound...............Molecular^13C (o/oo)PDB Phenanthrene...........178................-7.5 Anthracene.............178................-13.1 Fluoranthene...........202................-S.9 Pyrene.................202................-13.1 Chrysene+Triphenylene..228................-14.5 Benzo(ghi)fluoranthene.226................-14.2 Benzo(e)pyrene.........252................-22.3 Benzo(j)fluoranthene...252................-15.4 References 1. Gilmour et al. (1991) Meteoritics, 26, 337-338

Gilmour, I.; Pillinger, C.



Source identification of polycyclic aromatic hydrocarbons (PAHs) in sediment samples from the northern part of the Persian Gulf, Iran.  


Samples of surface sediments from the Iranian coast of the Persian Gulf were examined to determine the levels and sources of 15 polycyclic aromatic hydrocarbons (PAHs). Samples were collected from 30 sampling sites and analyzed for PAHs by gas chromatography-mass spectrometry (GC-MS). Total concentrations of PAHs ranged from 93 to 4,077 ng g(-1) dry weight. The PAH composition from 30 sampling sites was dominated by four-ring PAH compounds. Molecular indices based on the ratios of PAH concentrations were used to differentiate PAHs from pyrolitic to petrogenic and mixed origins. The results suggested that the main sources of PAHs in sediments from the studied region were mixed pyrolitic and petrogenic. Furthermore, benthic organisms in most of the investigated areas were not at ecotoxicological risk, according to the results from the effects range low (ERL)/effects range median (ERM) techniques suggested by the US Sediment Quality Guidelines (SQGs). PMID:25023748

Mirza, Roozbeh; Mohammadi, Mehdi; Faghiri, Iraj; Abedi, Ehsan; Fakhri, Ali; Azimi, Ali; Zahed, Mohammad Ali



Significance of Indirect Deposition on Wintertime PAH Concentrations in an Urban Northern California Creek  

PubMed Central

Abstract To investigate the main inputs and sources of polycyclic aromatic hydrocarbons (PAHs) into surface water, stream and precipitation samples were collected along an urban tributary to the Sacramento River, California. Dissolved, particulate, and colloid-bound PAHs were monitored four times between October 2004 and March 2005. The total PAH concentrations ranged from 192 to 3784?ng/L in surface water and from 77 to 236?ng/L in precipitation. Naphthalene, phenanthrene, pyrene, and benzo[g,h,i]perylene were the most abundant compounds in both rain and surface water. Surface water had truly dissolved PAH concentrations between 18 and 48?ng/L and precipitation had similar values (15–66?ng/L). PAHs larger than four rings were seldom found in the dissolved phase. Colloid-associated PAHs accounted for 4–25% of the total PAHs in rain, while they contributed only 0.1–6% to the total surface water PAHs. Indirect deposition (i.e., washoff of atmospheric particles previously deposited to land) of PAHs into surface water is likely a more significant input pathway for total PAHs than direct dry or wet deposition during the wet season in California's Mediterranean climate. During the sampling period, there was not an obvious seasonal variation in dissolved PAH concentrations of surface water despite an enormous wintertime increase in the total aqueous concentrations. Particulate matter carried by stormwater runoff was the major source of PAHs in surface water in the early rainy season; this material likely represents a combination of indirect atmospheric inputs and other non-atmospheric anthropogenic inputs (e.g., oil leaks and spills). Selected PAH ratios indicate that observed PAHs in rainwater came from pyrogenic sources and those in surface water had more complicated and variable origins. PMID:20485462

Kim, Daekyun; Young, Thomas M.



Removing PAH`s with cells on fibers  

SciTech Connect

There are over 1,500 sites contaminated with polycyclic aromatic hydrocarbons from coal gas plants. White rot fungi degrade PAH`s in soil, but the problem is to supply oxygen needed for growth of the fungus. When old cardboard boxes are buried with the fungus, oxygen is entrapped in the corrugations. A method for growing the fungus quickly is also described. Pseudomonade also degrade PAH and several strains of this bacterium have been grown on fibers. The fibers have high area, and when Celite is entrapped in the fibers, more area is provided.

Clyde, R. [Clyde Engineering, New Orleans, LA (United States)



Particle size distribution of n-alkanes and polycyclic aromatic hydrocarbons (PAHS) in urban and industrial aerosol of Algiers, Algeria.  


The distribution of ambient air n-alkanes and polycyclic aromatic hydrocarbons (PAHs) associated to particles with aerodynamic diameters lesser than 10 ?m (PM(10)) into six fractions (five stages and a backup filter) was studied for the first time in Algeria. Investigation took place during September of 2007 at an urban and industrial site of Algiers. Size-resolved samples (<0.49, 0.49-0.95, 0.95-1.5, 1.5-3.0, 3.0-7.2, and 7.2-10 ?m) were concurrently collected at the two sampling sites using five-stage high-volume cascade impactors. Most of n-alkanes (~72 %) and PAHs (~90 %) were associated with fine particles ? 1.5 ?m in both urban and industrial atmosphere. In both cases, the n-alkane contents exhibited bimodal or weakly bimodal distribution peaking at the 0.95-1.5-?m size range within the fine mode and at 7.3-10 ?m in the coarse mode. Low molecular weight PAHs displayed bimodal patterns peaking at 0.49-0.95 and 7.3-10 ?m, while high molecular weight PAHs exhibited mono-modal distribution with maximum in the <0.49-?m fraction. While the mass mean diameter of total n-alkanes in the urban and industrial sites was 0.70 and 0.84 ?m, respectively, it did not exceed 0.49 ?m for PAHs. Carbon preference index (~1.1), wax% (10.1-12.8), and the diagnostic ratios for PAHs all revealed that vehicular emission was the major source of these organic compounds in PM(10) during the study periods and that the contribution of epicuticular waxes emitted by terrestrial plants was minor. According to benzo[a]pyrene-equivalent carcinogenic power rates, ca. 90 % of overall PAH toxicity across PM(10) was found in particles ? 0.95 ?m in diameter which could induce adverse health effects to the population living in these areas. PMID:23982823

Ladji, R; Yassaa, N; Balducci, C; Cecinato, A



Characterization of PAHs within PM 10 fraction for ashes from coke production, iron smelt, heating station and power plant stacks in Liaoning Province, China  

NASA Astrophysics Data System (ADS)

Polycyclic aromatic hydrocarbons within PM 10 fraction of ashes from two coke production plants, one iron smelt plant, one heating station and one power plant were analyzed with GC-MS technique in 2009. The sum of 17 selected PAHs varied from 290.20 to 7055.72 ?g/g and the amounts of carcinogenic PAHs were between 140.33 and 3345.46 ?g/g. The most toxic ash was from the coke production plants and then from the iron smelt plant, coal-fired power plant and heating station according to BaP-based toxic equivalent factor (BaPeq) and BaP-based equivalent carcinogenic power (BaPE). PAHs profile of the iron smelt ash was significantly different from others with coefficient of divergence value higher than 0.40. Indicatory PAHs for coke production plants, heating station and coal-fired power plant were mainly 3-ring species such as Acy, Fl and Ace. While for iron smelt plant, they were Chr and BbF. Diagnostic ratios including Ant/(Ant + Phe), Flu/(Flu + Pyr), BaA/Chr, BbF/BkF, Ind/BghiP, IND/(IND + BghiP), BaP/BghiP, BaP/COR, Pyr/BaP, BaA/(BaA + Chr), BaA/BaP and BaP/(BaP + Chr) were calculated which were mostly different from other stacks for the iron smelt plant.

Kong, Shaofei; Shi, Jianwu; Lu, Bing; Qiu, Weiguang; Zhang, Baosheng; Peng, Yue; Zhang, Bowen; Bai, Zhipeng



Vertical distribution and source identification of polycyclic aromatic hydrocarbons (PAHs) in southwest of the Caspian Sea: most petrogenic events during the late Little Ice Age.  


In this study, 75 samples of two (210)Pb-dated cores from the southwest of the Caspian Sea were analysed for 30 compounds of polycyclic aromatic hydrocarbons (PAHs). The TPAH29 flux of the last six centuries ranged from 16.3 to 177.3 and 22.3 to 426.2 ng cm(-2)y(-1) in the Rezvanshahr and Anzali core sediments, respectively. Prior to 1840, four distinct maxima in PAH fluxes (61-426.2 ng cm(-2)y(-1)) with a low weathered petrogenic pattern were found in each of the core sediments. Simultaneity of distinct peaks of PAH fluxes before 1840 and Caspian Sea level high-stands during the Little Ice Age (LIA), revealed the high importance of this phenomenon in washing and transport of land-based oil pollution into the Caspian Sea. An overall increase in some diagnostic ratios (Flu/202, IP/276 and BaA/228), especially after 1940, indicated increase of pyrogenic PAHs as a result of industrial development in the catchment area. PMID:25131419

Varnosfaderany, Mohammad Nemati; Bakhtiari, Alireza Riyahi; Gu, Zhaoyan; Chu, Guoqiang



Perspective on Ecotoxicology of PAHs to Fish  

Microsoft Academic Search

This article provides a perspective on recent research on the effects of PAHs on fish. Fish are visible members of aquatic communities that are vulnerable to PAH contamination. The ecotoxicology of fish and PAHs can be complex. Fish are a diverse group that can have complicated life cycles and behavior and can be exposed to PAH-contaminated sediments and water by

Dennis T. Logan



PAH and metal mixtures in New Orleans soils and sediments.  


The purpose of this study is to determine the degree of PAH contamination and the association of PAHs with inorganic substances in soils and sediments of New Orleans. Bonnet Carré Spillway (BCS) (n = 5) provides modern baseline data, while urban soil samples (CTY) (n = 27) and sediment samples from Bayou St. John (BSJ) (n = 11) provide experimental data for New Orleans. Soil samples were collected from the top 2.5 cm of the surface, air-dried, and sieved (2 mm). Sediments samples were collected with a Wildco-Ekman bottom dredge, air-dried and finely ground. Accelerated solvent extraction (ASE) was used to release PAHs from the samples and analysis was conducted with gas chromatography-mass spectrometry (GC-MS). Metals were extracted using a 5:1 ratio of 1 mol/L nitric acid (room temperature) for soil and sediment samples, shaken for 2 h, centrifuged (1000 x g for 15 min) and filtered. Metal analysis was done by inductively coupled plasma-atomic emission spectrometry (ICP-AES). Mann-Whitney tests show PAH differences (P < 0.001). Ranking of total PAHs is, BSJ sediments (10.3 mg/kg) > CTY soils (3.7 mg/kg) > BCS alluvium (0.28 mg/kg). The sum of the metals are similar for BSJ sediments (698 mg/kg) and CTY soils (679 mg/kg) and significantly lower for BCS (189 mg/kg). Manganese of these samples is similar for each site. For paired samples, Pearson Product Moment Correlation tests reveal that many PAHs are strongly associated with each other at all locations. For BCS alluvium and BSJ sediments, total PAHs are not significantly associated with total metals. For CTY, most pairs of metals are significantly associated, and total soil PAHs are strongly associated with total soil metals (correlation 0.78, P = 4.9 x 10(-4)). The linear model, total soil PAH = 136.3 + 6.25 (total soil metals) forms the basis for a predicted PAH map of New Orleans. Previous empirical research demonstrates an association between soil lead and children's lead exposure. This study indicates that PAHs are part of the soil mixture of accumulated substances and by-products of industrial society that presents exposure potential in cities. PMID:11778953

Mielke, H W; Wang, G; Gonzales, C R; Le, B; Quach, V N; Mielke, P W



Distribution of PAHs in tissues of wetland plants and the surrounding sediments in the Chongming wetland, Shanghai, China.  


Polycyclic aromatic hydrocarbons (PAHs) concentrations were determined in sediments and three types of wetland plants collected from the intertidal flats in the Chongming wetland. The concentration of total PAHs in sediments ranged from 38.7 to 136.2 ngg(-1). Surface sediment concentrations were higher in regions with plant cover than in bare regions. Rhizome-layer sediments (56.8-102.4 ngg(-1)) contained less PAHs than surface sediments (0-5 cm). Concentrations of PAHs in plant tissues ranged from 51.9 to 181.2 ngg(-1), with highest concentrations in the leaves of Scirpus. Most of the PAHs in the leaves and other plant tissues were low molecular weight compounds (LMW, 2-4 rings), and a similar distribution pattern of PAHs in different types of plants was also observed. Source analysis indicated that plants and sediments both came from pyrogenic sources, but plants had additional petroleum contamination. The low ratio of benzo[a]anthracene over chrysene suggests that the wetland PAHs came mainly from long-distance atmospheric transportation. Significant bioaccumulation of PAHs from the sediments into plants was not observed for high molecular weight PAHs (HMW, 5-6 rings) in Chongming wetland. The small RCFs (root concentration factor from sediments) for HMW PAHs and large RCFs for LMW PAHs suggested that roots accumulated LMW PAHs selectively from sediments in Chongming wetland. PMID:22578517

Wang, Zucheng; Liu, Zhanfei; Yang, Yi; Li, Tao; Liu, Min



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

NASA Astrophysics Data System (ADS)

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.

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



Updated listing of haplotypes at the human phenylalanine hydroxylase (PAH) locus  

SciTech Connect

Analysis of mutant PAH chromosomes has identified approximately 60 different single-base substitutions and deletions within the PAH locus. Nearly all of these molecular lesions are in strong linkage disequilibrium with specific RFLP haplotypes in different ethnic populations. Thus, haplotype analysis is not only useful for diagnostic purposes but is proving to be a valuable tool in population genetic studies of the origin and spread of phenylketonuria alleles in human populations. PCR-based methods have been developed to detect six of the eight polymorphic restriction sites used for determination of RFLP haplotypes at the PAH locus. A table of the proposed expanded haplotypes is given.

Eisensmith, R.C.; Woo, S.L.C. (Baylor College of Medicine, Houston, TX (United States))



Characteristics of the PAH emissions from the incineration of livestock wastes with/without APCD.  


This study was conducted on two batch-type livestock waste incinerators, including the one with an air-pollution control device (APCD)-one wet scrubber (WSB) and the other without APCD for the disposal of livestock wastes. The concentration and composition of 21 individual polycyclic aromatic hydrocarbons (PAHs) in the stack flue gas (gas and particle phases), bottom ash, and effluent of WSB were determined. Stack flue gas samples were collected by a PAH stack-sampling system. Twenty-one individual PAHs were analyzed by a gas chromatography/mass spectrometer (GC/MS). Due to the low combustion temperature, a remarkable and significant increase in the total-PAH concentration of emission from the stack with APCD was observed when compared with the case without APCD. Measured total-PAH emission factors were 285 and 2.86 mg/kg waste for the incineration with and without APCD, respectively, while BaP (the most carcinogenic PAH) emission factors were 0.79 and 0.12 mg/kg waste for the incineration with and without APCD. The total-PAH output/input mass ratios averaged 0.011 and 0.004 with and without APCD, respectively. The result reveals that the PAH content in the auxiliary fuel during the incinerating process could affect the emission of PAH. PMID:12504163

Chen, Shui-Jen; Hsieh, Lien-Te; Chiu, Shui-Chi



PAH composition and potential sources for sediment samples from the Beaufort and Barents Seas  

SciTech Connect

Sediment grabs and cores have been analyzed for parent and alkyl PAHs (polycyclic aromatic hydrocarbons) and time horizons have been determined using radionuclide distributions. PAH concentrations are significantly higher (2 to 20 times) in the Mackenzie River and the Beaufort Sea than in sediment from the Barents Sea. Concentrations exhibit little change between the Mackenzie River and shelf, but decrease slightly at the shelf edge. Barents Sea sediments have the highest concentrations in the southeast (near the major rivers), are slightly lower in the north and west of the sea, and are lowest near Novaya Zemlya. In most cases there is little change in PAH composition between surface layers and deeper sediments (10--20 cm) that contain no detectable bomb radionuclides. PAH profiles and principal components analysis (PCA) clearly distinguish PAH sources for the Arctic. Barents Sea sediments are most similar to Arctic atmospheric aerosols in their PAH molecular-mass ratios and PCA projections. Samples from the west and north sides of the Barents Sea are consistent with a petroleum source, while samples from other areas have combustion sources. Anthropogenic combustion inputs are particularly important in the southern Barents Sea, whereas natural inputs are important to the Beaufort Sea. The uniformity and the relatively high concentration of Beaufort Sea PAHs reflects a river dominated input of natural PAHs which tends to overwhelm any anthropogenic sources. Despite the greater anthropogenic influence in the Barents Sea, PAH concentrations in Barents Sea sediments are generally lower than in Beaufort Sea sediments.

Yunker, M.B.; Macdonald, R.W.; Snowdon, L.R.; Smith, J.N.



Determination of polycyclic aromatic hydrocarbons (PAHs) in shrimp.  


A simple and rapid method for determining polycyclic aromatic hydrocarbons (PAHs) in shrimp is described. For sample preparation, the quick and simple QuEChERS procedure was used. Reverse-phase chromatography using an octadecyl silica (C18) column and water/acetonitrile gradient elution was used to separate analyte mixtures. After separation, PAHs were detected using liquid chromatography-tandem mass spectrometry (LC-MS/MS) equipped with the atmospheric pressure photoionization (PhotoSpray APPI) source operating in the positive-ion mode. In this methodology, all 16 common PAHs were used and toluene served as a charged dopant to efficiently ionize analyte molecules through secondary reactions. Spikes were performed at 0.2 and 1 ?g/g with and without primary and secondary amine (PSA) sorbent cleanup. Recoveries of PAHs were good, with ion ratios that agreed well between the spikes and standards. Without cleanup at 0.2 ?g/mL, seven compounds had relatively low recovery (49-69%) and one compound, naphthalene, had a somewhat high recovery of 129%. At 1 ?g/mL without cleanup, only three compounds had slightly lower recovery (66-67%). When PSA cleanup was performed, all PAH recoveries were within 75-125% at both spike levels. PMID:21062062

Smoker, Michael; Tran, Kevin; Smith, Robert E



Recent Progress in DIB Research: Survey of PAHS and DIBS  

NASA Technical Reports Server (NTRS)

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.

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



Empirical derivation of the reference region for computing diagnostic sensitive fluorodeoxyglucose ratios in Alzheimer's disease based on the ADNI sample,  

E-print Network

fluorodeoxyglucose ratios in Alzheimer's disease based on the ADNI sample, Jerod M. Rasmussen a, , Anita Lakatos a , Steven G. Potkin a for the Alzheimer's Disease Neuroimaging Initiative a Department of Psychiatry on the dataset collected by the Alzheimer's Disease Neuroimaging Initiative (ADNI) study. Candidate reference

Kruggel, Frithjof


Atmospheric carbon diooxide mixing ratios from the NOAA Climate Monitoring and Diagnostics Laboratory cooperative flask sampling network, 1967-1993  

SciTech Connect

This data report documents monthly atmospheric CO{sub 2} mixing ratios and measurements obtained by analyzing individual flask air samples for the NOAA/CMDL global cooperative flask sampling network. Measurements include land-based sampling sites and shipboard measurements covering 14 latitude bands in the Pacific Ocean and South China Sea. Analysis of the NOAA/CMDL flask CO{sub 2} database shows a long-term increase in atmospheric CO{sub 2} mixing ratios since the late 1960s. This report describes how the samples are collected and analyzed and how the data are processed, defines limitations, and restrictions of the data, describes the contents and format of the data files, and provides tabular listings of the monthly carbon dioxide records.

Conway, T.J.; Tans, P.P. [National Oceanic and Atmospheric Administration, Boulder, CO (United States); BBoden, T.A. [Oak Ridge National Lab., TN (United States)



Empirical derivation of the reference region for computing diagnostic sensitive ¹?fluorodeoxyglucose ratios in Alzheimer's disease based on the ADNI sample.  


Careful selection of the reference region for non-quantitative positron emission tomography (PET) analyses is critically important for Region of Interest (ROI) data analyses. We introduce an empirical method of deriving the most suitable reference region for computing neurodegeneration sensitive (18)fluorodeoxyglucose (FDG) PET ratios based on the dataset collected by the Alzheimer's Disease Neuroimaging Initiative (ADNI) study. Candidate reference regions are selected based on a heat map of the difference in coefficients of variation (COVs) of FDG ratios over time for each of the Automatic Anatomical Labeling (AAL) atlas regions normalized by all other AAL regions. Visual inspection of the heat map suggests that the portion of the cerebellum and vermis superior to the horizontal fissure is the most sensitive reference region. Analyses of FDG ratio data show increases in significance on the order of ten-fold when using the superior portion of the cerebellum as compared with the traditionally used full cerebellum. The approach to reference region selection in this paper can be generalized to other radiopharmaceuticals and radioligands as well as to other disorders where brain changes over time are hypothesized and longitudinal data is available. Based on the empirical evidence presented in this study, we demonstrate the usefulness of the COV heat map method and conclude that intensity normalization based on the superior portion of the cerebellum may be most sensitive to measuring change when performing longitudinal analyses of FDG-PET ratios as well as group comparisons in Alzheimer's disease. This article is part of a Special Issue entitled: Imaging Brain Aging and Neurodegenerative disease. PMID:21958592

Rasmussen, Jerod M; Lakatos, Anita; van Erp, Theo G M; Kruggel, Frithjof; Keator, David B; Fallon, James T; Macciardi, Fabio; Potkin, Steven G



Diagnostic accuracy of the urinary albumin: creatinine ratio determined by the CLINITEK Microalbumin and DCA 2000+ for the rule-out of albuminuria in chronic kidney disease.  


An increased urinary albumin excretion (albuminuria) is an established test for the early detection of renal disease and is also recognized as a risk factor for cardiovascular disease and mortality in a number of clinical settings. There is an established body of data which shows that a random urinary albumin:creatinine ratio (ACR) based on a random urine sample correlates well with 24-hour urinary albumin excretion measurement. However, there is little data to show whether specific point-of-care testing devices can be used to rule-in or rule-out increased urinary albumin excretion in comparison to a 24-hour urinary albumin excretion measurement. This study evaluated the ability to rule-in or rule-out albuminuria in a cohort of patients attending a renal outpatient clinic, using the urinary ACR determined by the CLINITEK Microalbumin (Siemens Healthcare Diagnostics Inc., Deerfield, US) a semi-quantitative strip test, and by the DCA 2000+ (Siemens Healthcare Diagnostics Inc.) a quantitative cassette based test using 3 random urine samples collected within a 24-hour period compared to 24-hour urinary albumin measurement. The CLINITEK system was shown to be a reliable test for ruling out increased urinary albumin excretion with negative likelihood ratios less than 0.05 above the 24-hour urinary albumin excretion rate of 30 mg/24 h (threshold for microalbuminuria), and less than 0.01 above the albumin excretion rate of 100 mg/24 h. The DCA 2000+ system demonstrated similar performance as a rule-out test, with likelihood ratios of less than 0.02 at 24-hour albumin excretion rates above 30 mg/24 h. Both the CLINITEK and DCA 2000+ systems could be used to rule-out increased urinary albumin excretion at the albumin excretion cut-off rate of 30 mg/24 h in this cohort of patients. PMID:18834870

Guy, Mark; Newall, Ronald; Borzomato, Joanna; Kalra, Philip A; Price, Christopher




Microsoft Academic Search

This review gives a short introduction in the origin, occurrence and detection of polycyclic aromatic hydrocarbons (PAHs). Emphasis lies on immunochemical detection methods for PAH compounds, such as ELISA, RIA, fluoroimmunosensors, QCM immunosensors and electrochemical immunosensors, but also on immunosorbents and commercial immunoassay kits for PAHs. Possibilities and limitations of these methods compared to standard methods, such as HPLC and

Karsten A. Fähnrich; Miloslav Pravda; George G. Guilbault



Protective role of fine silts for PAH in a former industrial soil.  


An original combined organic geochemistry and soil science approach was used to elucidate PAH availability controlling factors in a multi-contaminated industrial soil. Water granulodensimetric fractionation was applied to obtain five water-stable material fractions. These were characterized by elemental, molecular and mineral analysis, and microscopic observations. Among the different fractions, fine silts distinguished themselves by higher carbon and nitrogen contents, lower C/N ratio, an enrichment in total PAH and especially high molecular weight compounds, a coal tar signature and the lowest PAH availability. This fine silt fraction seemed to play a protective role for PAH that might be explained by its size and/or its specific reactivity. The mineral phases present in this fraction were proposed to explain the protection of organic matter. This led to a specific molecular signature of OM, having higher sorption properties both processes (sorption and mineral-bound protection) resulting in a lower PAH availability. PMID:23665618

Pernot, Audrey; Ouvrard, Stéphanie; Leglize, Pierre; Faure, Pierre



Thermodynamic driving forces for PAH isomerization and growth during thermal treatment of polluted soils.  


For a limiting case of thermodynamic equilibrium, the importance of two classes of thermal chemical reactions that modify the structure and bioactivity of polycyclic aromatic hydrocarbons (PAH) was assessed computationally. These reactions are molecular weight (MW) growth by acetylene addition, and intramolecular rearrangement (isomerization). Temperatures (300-1100 degrees C), and the chemical environment (C(2)H(2)/H(2) molar ratios) were selected for relevancy to thermal treatment of PAH-contaminated soils under oxygen-free conditions. Molecular mechanics methods [MM3(92)] were used to compute thermochemical properties for calculation of equilibrium constants, i.e., heats of formation, standard entropies, and heat capacities for 30 PAH with empirical formulae C(14)H(10), C(16)H(10), C(18)H(10), C(18)H(12), C(20)H(10), and C(20)H(12). Included were 11 PAH containing only six-membered rings and 19 PAH containing both five- and six-membered rings. For each of these PAH the calculations predict that with increasing temperature, isomerization increases the "complexity" of the PAH mixture, i.e., the relative abundance of each PAH isomer in the mixture other than the most stable isomer, increases. Isomerization also partially transforms non-mutagens to mutagens, e.g., pyrene and benzo[e]pyrene to fluoranthene and benzo[a]pyrene, respectively, and partially converts cyclopenta[c, d]pyrene (CPEP) and chrysene, both human cell mutagens, to one and three additional human cell mutagens, respectively. Acetylene addition transforms the non-mutagens phenanthrene and pyrene to the mutagens triphenylene and CPEP, respectively. Some of the predicted PAH have been observed elsewhere among the products of aromatics pyrolysis. This study elucidates PAH reactivity for comparison with measurements, and identifies PAH reactions to be monitored and avoided in soil thermal decontamination and other waste remediation processes. PMID:11040395

Pope, C J; Peters, W A; Howard, J B



Compact point-detection fluorescence spectroscopy system for quantifying intrinsic fluorescence redox ratio in brain cancer diagnostics  

PubMed Central

We report the development of a compact point-detection fluorescence spectroscopy system and two data analysis methods to quantify the intrinsic fluorescence redox ratio and diagnose brain cancer in an orthotopic brain tumor rat model. Our system employs one compact cw diode laser (407 nm) to excite two primary endogenous fluorophores, reduced nicotinamide adenine dinucleotide, and flavin adenine dinucleotide. The spectra were first analyzed using a spectral filtering modulation method developed previously to derive the intrinsic fluorescence redox ratio, which has the advantages of insensitivty to optical coupling and rapid data acquisition and analysis. This method represents a convenient and rapid alternative for achieving intrinsic fluorescence-based redox measurements as compared to those complicated model-based methods. It is worth noting that the method can also extract total hemoglobin concentration at the same time but only if the emission path length of fluorescence light, which depends on the illumination and collection geometry of the optical probe, is long enough so that the effect of absorption on fluorescence intensity due to hemoglobin is significant. Then a multivariate method was used to statistically classify normal tissues and tumors. Although the first method offers quantitative tissue metabolism information, the second method provides high overall classification accuracy. The two methods provide complementary capabilities for understanding cancer development and noninvasively diagnosing brain cancer. The results of our study suggest that this portable system can be potentially used to demarcate the elusive boundary between a brain tumor and the surrounding normal tissue during surgical resection. PMID:21456877

Liu, Quan; Grant, Gerald; Li, Jianjun; Zhang, Yan; Hu, Fangyao; Li, Shuqin; Wilson, Christy; Chen, Kui; Bigner, Darell; Vo-Dinh, Tuan



Compact point-detection fluorescence spectroscopy system for quantifying intrinsic fluorescence redox ratio in brain cancer diagnostics  

NASA Astrophysics Data System (ADS)

We report the development of a compact point-detection fluorescence spectroscopy system and two data analysis methods to quantify the intrinsic fluorescence redox ratio and diagnose brain cancer in an orthotopic brain tumor rat model. Our system employs one compact cw diode laser (407 nm) to excite two primary endogenous fluorophores, reduced nicotinamide adenine dinucleotide, and flavin adenine dinucleotide. The spectra were first analyzed using a spectral filtering modulation method developed previously to derive the intrinsic fluorescence redox ratio, which has the advantages of insensitivty to optical coupling and rapid data acquisition and analysis. This method represents a convenient and rapid alternative for achieving intrinsic fluorescence-based redox measurements as compared to those complicated model-based methods. It is worth noting that the method can also extract total hemoglobin concentration at the same time but only if the emission path length of fluorescence light, which depends on the illumination and collection geometry of the optical probe, is long enough so that the effect of absorption on fluorescence intensity due to hemoglobin is significant. Then a multivariate method was used to statistically classify normal tissues and tumors. Although the first method offers quantitative tissue metabolism information, the second method provides high overall classification accuracy. The two methods provide complementary capabilities for understanding cancer development and noninvasively diagnosing brain cancer. The results of our study suggest that this portable system can be potentially used to demarcate the elusive boundary between a brain tumor and the surrounding normal tissue during surgical resection.

Liu, Quan; Grant, Gerald; Li, Jianjun; Zhang, Yan; Hu, Fangyao; Li, Shuqin; Wilson, Christy; Chen, Kui; Bigner, Darell; Vo-Dinh, Tuan



Biota: sediment partitioning of aluminium smelter related PAHs and pulp mill related diterpenes by intertidal clams at Kitimat, British Columbia.  


The question of polycyclic aromatic hydrocarbon (PAH) bioavailability and its relationship to specific PAH sources with different PAH binding characteristics is an important one, because bioavailability drives PAH accumulation in biota and ultimately the biochemical responses to the PAH contaminants. The industrial harbour at Kitimat (British Columbia, Canada) provides an ideal location to study the bioavailability and bioaccumulation of sediment hydrocarbons to low trophic level biota. Samples of soft shell clams (Mya arenaria) and intertidal sediment collected from multiple sites over six years at various distances from an aluminium smelter and a pulp and paper mill were analysed for 106 PAHs, plant diterpenes and other aromatic fraction hydrocarbons. Interpretation using PAH source ratios and multivariate data analysis reveals six principal hydrocarbon sources: PAHs in coke, pitch and emissions from anode combustion from the aluminium smelter, vascular plant terpenes and aromatised terpenes from the pulp and paper mill, petroleum PAHs from shipping and other anthropogenic activities and PAHs from natural plant detritus. Harbour sediments predominantly contain either pitch or pyrogenic PAHs from the smelter, while clams predominantly contain plant derived PAHs and diterpenes from the adjacent pulp mill. PAHs from the smelter have low bioavailability to clams (Biota-Sediment Accumulation Factors; BSAFs <1 for pitch and coke; <10 for anode combustion, decreasing to ?0.1 for the mass 300 and 302 PAHs), possibly due to binding to pitch or soot carbon matrices. Decreases in PAH isomer ratios between sediments and clams likely reflect a combination of variation in uptake kinetics of petroleum PAHs and compound specific metabolism, with the importance of petroleum PAHs decreasing with increasing molecular weight. Plant derived compounds exhibit little natural bioaccumulation at reference sites, but unsaturated and aromatised diterpenes released from resins by industrial pulping processes are readily accumulated by the clams (BSAFs >500). Thus while most of the smelter associated PAHs in sediments may not be bioavailable to benthic organisms, the plant terpenes (including retene, totarol, ferruginol, manool, dehydroabietane and other plant terpenes that form the chemical defence mechanism of conifers) released by pulp mills are bioavailable and possess demonstrated toxic properties. The large scale release of plant terpenes by some of the many pulp mills located in British Columbia and elsewhere represents a largely undocumented risk to aquatic biota. PMID:21788067

Yunker, Mark B; Lachmuth, Cara L; Cretney, Walter J; Fowler, Brian R; Dangerfield, Neil; White, Linda; Ross, Peter S



The diagnostic significance of the immunoglobulin A to M and A to total ratios in the pancreatoduodenal fluid of patients with benign and malignant pancreatic diseases.  


Immunoglobulins A, M and G in the pancreato-duodenal fluid (PDF) of 35 pancreatic disease-free individuals and 48 patients with chronic pancreatitis (25), hypersecretory disorders (10), renal transplanted (4) and with pancreatic cancer (9), were determined by a single radial immunodiffusion method. Although a trend of immunoglobulin hypersecretion in benign diseases and hyposecretion in malignancies was present, individual levels of Ig-A and Ig-M differed statistically only between cancer and other groups. Calculating the ratios of Ig-A to Ig-M (A/M) and Ig-A to total immunoglobulin contents (A/T) in the PDF of patients with chronic pancreatitis or cancer, however, a significantly higher or lower ratio, respectively, was found compared to control group. Differences in A/M ratios could not be detected between patients with benign diseases, but were constantly present when these patients were compared to pancreatic cancer. The underlying mechanism(s) of the disturbed immunosecretory system in pancreatic diseases remains speculative. Nevertheless, immunoglobulin measurements in the PDF of patients with pancreatic diseases offer a simple diagnostic aid in clinical differentiation of pancreatic pathology. PMID:356594

Bramis, J P; Messer, J; Nacchiero, M; Dreiling, D A



Polycyclic aromatic hydrocarbons (PAHs) in the mariculture zones of China's northern Yellow Sea.  


Polycyclic aromatic hydrocarbons (PAHs) were detected in water and sediment samples collected from three mariculture zones in China's northern Yellow Sea. In these samples, total PAH concentrations ranged from 110.8 ng/L to 997.2 ng/L and 142.2 ng/gdry weight (dw) to 750.2 ng/gdw, respectively. The log KOC values of the various PAH compounds examined in this study increased with the log KOW values, which is consistent with the prediction regarding PAH behavior in the environment. However, these KOC values were lower than the predicted values as a result of the effects of organic matters, which were abundant in the mariculture water. The isomeric ratios of the PAHs in sediment indicated that the source of the PAHs in the mariculture zones were mainly pyrolytic. The TEQ(carc) values of PAHs ranged from 7 ng TEQ/gdw to 92 ng TEQ/gdw, and only a few samples met the safe criterion with respect to individual PAH concentrations. PMID:24952456

Zong, Humin; Ma, Xindong; Na, Guangshui; Huo, Chuanlin; Yuan, Xiutang; Zhang, Zhifeng



Source apportionment of PAHs using Unmix model for Yantai costal surface sediments, China.  


16 Polycyclic aromatic hydrocarbons (PAHs) in 20 surface sediments from Yantai offshore area were measured. The total PAHs concentrations varied from 450.0 to 4,299.0 ng/g, with a mean of 2,492.9 ng/g. The high molecular weight (HMW) PAHs were most abundant and the ratio ranged from 54.9 % to 81.6 % in all sampling stations, indicating that pyrogenic sources were a predominant contribution to PAHs pollution. The source contributions of PAHs were estimated based on the EPA Unmix 6.0 receptor model. The data were well simulated due to a high correlation coefficient between predicted and measured PAHs concentration (R(2) = 0.99). A mixed source of coal combustion and traffic pollution contributed to 38.9 % of the measured PAHs, followed by diesel emission (38.8 %) and a mixed source of biomass combustion and gasoline engine emissions (22.3 %). The current findings further validated that Unmix model could be applied to apportion the sources of PAHs in sediments. PMID:24292847

Lang, Yin-Hai; Yang, Wei



Hybrid time dependent/independent solution for the He I line ratio temperature and density diagnostic for a thermal helium beam with applications in the scrape-off layer-edge regions in tokamaks  

SciTech Connect

Spectroscopic studies of line emission intensities and ratios offer an attractive option in the development of non-invasive plasma diagnostics. Evaluating ratios of selected He I line emission profiles from the singlet and triplet neutral helium spin systems allows for simultaneous measurement of electron density (n{sub e}) and temperature (T{sub e}) profiles. Typically, this powerful diagnostic tool is limited by the relatively long relaxation times of the {sup 3}S metastable term of helium that populates the triplet spin system, and on which electron temperature sensitive lines are based. By developing a time dependent analytical solution, we model the time evolution of the two spin systems. We present a hybrid time dependent/independent line ratio solution that improves the range of application of this diagnostic technique in the scrape-off layer (SOL) and edge plasma regions when comparing it against the current equilibrium line ratio helium model used at TEXTOR.

Munoz Burgos, J. M. [Oak Ridge Institute for Science Education, Oak Ridge, Tennessee 37830 (United States); Schmitz, O. [Institute fuer Energieforschung-Plasmaphysik, Forschungszentrum Juelich, Association EURATOM-FZJ, Trilateral Euregio Cluster, D-52425 Juelich (Germany); Loch, S. D.; Ballance, C. P. [Physics Department, Auburn University, Auburn, Alabama 36849 (United States)



Hybrid time dependent/independent solution for the He I line ratio temperature and density diagnostic for a thermal helium beam with applications in the scrape-off layer-edge regions in tokamaks  

NASA Astrophysics Data System (ADS)

Spectroscopic studies of line emission intensities and ratios offer an attractive option in the development of non-invasive plasma diagnostics. Evaluating ratios of selected He I line emission profiles from the singlet and triplet neutral helium spin systems allows for simultaneous measurement of electron density (ne) and temperature (Te) profiles. Typically, this powerful diagnostic tool is limited by the relatively long relaxation times of the 3S metastable term of helium that populates the triplet spin system, and on which electron temperature sensitive lines are based. By developing a time dependent analytical solution, we model the time evolution of the two spin systems. We present a hybrid time dependent/independent line ratio solution that improves the range of application of this diagnostic technique in the scrape-off layer (SOL) and edge plasma regions when comparing it against the current equilibrium line ratio helium model used at TEXTOR.

Muñoz Burgos, J. M.; Schmitz, O.; Loch, S. D.; Ballance, C. P.



Biodegradation of PAH`s in sediment-slurry processes  

SciTech Connect

The focus of this research was to examine biodegradation of polynuclear aromatic hydrocarbons (PAHs) in lab scale slurry reactors. The studies summarized in this paper focused on the rate and extent of contaminant release from the sediments, oxygen demand of anaerobic sediments, and the rate and extent of PAH biodegradation achieved. Mass balances were used in all cases. The studies identified several factors which may influence the design or operation of bioreactors used for sediment remediation. Mixing had the greatest effect on the rate and extent of contaminant release; solids loading and aeration had little or no effect in mixed reactors. In unmixed reactors, aerated systems showed faster rates of contaminant release than unaerated systems, indicating that the aeration process itself provides some degree of mixing. The maximum extent of mineralization appeared to be reached within five days in mixed systems; significantly lower mineralization was seen in reactors with insufficient mixing.

Hughes, J.B.; Beckles, D.; Chandra, S. [Rice Univ., Houston, TX (United States)] [and others



Occupational PAH Exposures during Prescribed Pile Burns  

PubMed Central

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 ?g 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 ?g 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

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



PAH emission from the industrial boilers.  


Polycyclic aromatic hydrocarbons (PAHs) emitted from 25 industrial boilers were investigated. The fuels used for these 25 boilers included 21 heavy oil, two diesel, a co-combustion of heavy oil and natural gas (HO+NG) and a co-combustion of coke oven gas and blast furnace gas (COG+BFG) boilers. PAH samples from the stack flue gas (gas and particle phases) of these 25 boilers were collected by using a PAH stack sampling system. Twenty one individual PAHs were analyzed primarily by a gas chromatography/mass spectrometer (GC/MS). Total-PAH concentration in the flue gas of 83 measured data for these 25 boiler stacks ranged between 29.0 and 4250 microg/m(3) and averaged 488 microg/m(3). The average of PAH-homologue mass (F%) counted for the total-PAH mass was 54.7%, 9.47% and 15.3% for the 2-ring, 3-ring and 4-ring PAHs, respectively. The PAHs in the stack flue gas were dominant in the lower molecular weight PAHs. The emission factors (EFs) of total-PAHs were 13,300, 2920, 2880 and 208 microg/kg-fuel for the heavy oil, diesel, HO+NG and COG+BFG fueled-boiler, respectively. Nap was the most predominant PAH occurring in the stack flue gas. In addition, the EF of 21 individual PAHs in heavy-oil boiler were almost the highest among the four various fueled-boilers except for those of FL and BkF in the diesel boiler. Furthermore, the EF of total-PAHs or BaP for heavy oil were both one order of magnitude higher than that for the diesel-fueled boiler. PMID:10502602

Li, C; Mi, H; Lee, W; You, W; Wang, Y



Distribution, sources and potential toxicological significance of polycyclic aromatic hydrocarbons (PAHs) in surface soils of the Yellow River Delta, China.  


PAH concentrations of 61 surface soil samples collected from the Yellow River Delta (YRD), China were measured to determine occurrence levels, sources, and potential toxicological significance of PAHs. The total concentrations of ?PAHs ranged from 27 to 753 ng/g d.w., with a mean of 118±132 ng/g. The highest concentrations was found in the mid-southern part of the YRD (753 ng/g), which was associated with the oil exploration. The ratios indicated that the PAHs throughout the YRD were mostly of pyrogenic origin; while various sites in mid-southern part in the region were derived mainly from the petrogenic sources. Multivariate statistical analyses supported that the PAHs in surface soils of the YRD were principally from the coal and biomass combustion, petroleum spills, and/or vehicular emissions. The toxic assessment suggested that the PAHs in soils were at low potential of ecotoxicological contamination level for the YRD. PMID:24801799

Yuan, Hongming; Li, Tiegang; Ding, Xigui; Zhao, Guangming; Ye, Siyuan



Evaluating potential non-point source loading of PAHs from contaminated soils: A fugacity-based modeling approach.  


Soils contaminated by Polycyclic Aromatic Hydrocarbons (PAHs) are subject to significant non-point source (NPS) pollution during rainfall events. Recent studies revealed that the classic enrichment ratio (ER) approach may not be applicable to PAHs. This study developed a model to estimate the ER of PAHs which innovatively applies the fugacity concept. The ER model has been validated with experimental data, which suggested that the transport of PAHs not only depends on their physicochemical properties, but on the sediment composition and how the composition evolves during the event. The modeling uncertainty was systematically examined, and found to be highly compound-dependent. Based on the ER model, a strategy was proposed to practically evaluate the potential NPS loading of PAHs in watersheds with heterogeneous soils. The study results have important implications to modeling and managing the NPS pollution of PAHs (or other chemicals alike) at a watershed scale. PMID:25282126

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



The hydrogen coverage of interstellar PAHs  

NASA Technical Reports Server (NTRS)

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

Barker, J. R.; Cohen, M.; Tielens, Alexander G. G. M.; Allamandola, Louis J.; Barker, J. R.; Barker, J. R.



Head-to-head comparison of basal stenosis resistance index, instantaneous wave-free ratio, and fractional flow reserve: diagnostic accuracy for stenosis-specific myocardial ischaemia.  


Aims: We sought to compare the diagnostic accuracy of basal stenosis resistance index (BSR), instantaneous wave-free ratio (iFR) and fractional flow reserve (FFR) for stenosis-specific myocardial ischaemia identified by means of a combined reference standard of myocardial perfusion scintigraphy and the hyperaemic stenosis resistance index. Methods and results: BSR and FFR were determined for 299 coronary stenoses, iFR was determined for 85 coronary stenoses (iFR cohort). The discriminative value for stenosis-specific myocardial ischaemia was compared by means of the area under the receiver operating characteristic (ROC) curves (AUC). Classification agreement with the reference standard was determined according to ROC curve-derived ischaemic cut-off values, as well as according to clinical cut-off values, equivalent to the 0.80 FFR cut-off. Across all stenoses, the discriminative value of BSR and FFR was equivalent (AUC: 0.90 and 0.91, respectively, p=0.46). In the iFR cohort, the discriminative value was equivalent for BSR, iFR, and FFR (AUC: 0.88, 0.84, and 0.88, respectively; p?0.20 for all). At both ischaemic as well as clinical cut-off values, classification agreement with the reference standard was equivalent for BSR and FFR across all stenoses, as well as for BSR, iFR, and FFR in the iFR cohort. Conclusions: BSR, iFR, and FFR have equivalent diagnostic accuracy for the detection of ischaemia-generating coronary stenoses. PMID:25169594

van de Hoef, Tim P; Meuwissen, Martijn; Escaned, Javier; Sen, Sayan; Petraco, Ricardo; van Lavieren, Martijn A; Echavarria-Pinto, Mauro; Nolte, Froukje; Nijjer, Sukhjinder; Chamuleau, Steven A J; Voskuil, Michiel; van Eck-Smit, Berthe L F; Verberne, Hein J; Henriques, José P S; Koch, Karel T; de Winter, Robbert J; Spaan, Jos A E; Siebes, Maria; Tijssen, Jan G P; Davies, Justin E; Piek, Jan J



A source mixing model to apportion PAHs from coal tar and asphalt binders in street pavements and urban aquatic sediments.  


Present-day and more than 30 years old road and footpath pavements from Auckland, New Zealand were analysed for PAHs to test the hypothesis that coal tar based pavement binders contribute to unusually high PAH concentrations in adjacent stream and estuarine sediments. Total PAH (?(28)PAH) concentrations in the dichloromethane-soluble fraction ("binder"), comprising 5-10% of pavement mass, were as high as 200,000 mgkg(-1) (10,000 mgkg(-1) in binder+aggregate). Older and deeper pavement layers were strongly pyrogenic, whereas pavement layers from recently sealed roads had a more petrogenic composition and more than 1000 times lower ?(28)PAH concentrations. Source identification analysis using three PAH isomer ratio pairs (benz(a)anthracene/(benz(a)anthracene+chrysene); benzo(a)pyrene/(benzo(a)pyrene+benzo(e)pyrene); and indeno(1,2,3-cd)pyrene/(indeno(1,2,3-cd)pyrene+benzo(g,h,i)perylene) revealed low PAH (bitumen) pavements to have consistently lower isomer ratios than high PAH (coal tar) samples. Moreover, pavement data for one isomer ratio (e.g. benzo(a)pyrene/(benzo(a)pyrene+benzo(e)pyrene) were highly correlated with those of another isomer ratio (e.g. benz(a)anthracene/(benz(a)anthracene+chrysene) and were bounded at their lower and higher extremes by the characteristics of pure bitumen and coal tar, respectively, suggesting that PAH composition of a given pavement sample could be accounted for by conservative mixing between coal tar and bitumen as source materials. A concentration-weighted mixing model, with coal tar and bitumen as source materials, explained more than 80% of the variance in isomer ratios and enveloped the entire PAH compositional and concentration range encountered. PAH composition and concentrations in adjacent stream sediments (> 15 mgkg(-1) dry weight) were consistent with diluted coal tar material as a principal PAH source. Due to the very high PAH concentrations of coal tar, a coal tar content of as little as 0.01% of total sediment mass can account for more than 90% of PAH concentrations in adjacent stream sediments. PMID:20843538

Ahrens, Michael J; Depree, Craig V



Toxicity evaluation of PAH mixtures using Microtox  

SciTech Connect

Polycyclic aromatic hydrocarbons (PAH) are produced from both natural and anthropogenic combustion processes. PAHs are known to be toxic and carcinogenic, are prevalent at many hazardous waste sites, and pose a potential risk to both ecological and human health. To date, few researchers have assessed the toxicity of polycyclic aromatic hydrocarbon (PAH) mixtures. The toxicity of chrysene, anthracene, pyrene, phenanthrene, fluoranthrene, acenaphthene, fluorene, and naphthalene were evaluated using Microtox, and acute toxicity assay that uses bioluminescent bacteria, Photobacterium phosphoreum, to measure toxicity. In this study, the toxicities of 2, 3, and 4 ring PAHs were determined for individual compounds. Synergistic or additive effects of PAH mixtures was assessed by comparing the toxicity of mixtures with that of pure compounds. Each PAH or mixture was evaluated at their respective water solubility concentrations, For individual PAHs tested, the toxicity of PAHs is inversely related to water solubility. Mixtures of two and three PAHs with disparate water solubilities resulted in synergistic interactions. Antagonistic interactions, a decrease in toxicity, were observed for mixtures of similar water solubilities.

Thompkins, J.; Guthrie, E.; Pfaender, F. [Univ. of North Carolina, Chapel Hill, NC (United States)



PAHs concentration and toxicity in organic solvent extracts of atmospheric particulate matter and sea sediments.  


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 ?g(-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. PMID:22797225

Ozaki, Noriatsu; Takeuchi, Shin-ya; Kojima, Keisuke; Kindaichi, Tomonori; Komatsu, Toshiko; Fukushima, Takehiko



Bacterial biodegradation of polycyclic aromatic hydrocarbons (PAH) and potential effects of surfactants on PAH bioavailability  

SciTech Connect

The purposes of this project were to evaluate whether indigenous microorganisms from polycyclic aromatic hydrocarbons (PAH)-contaminated soils produce surfactants (biosurfactants) as a means of enhancing the bioavailability of PAH; to improve the understanding of the general physiology of a diverse group of PAH-degrading bacteria; and to study in general how surfactants influence the biodegradation of hydrophobic chemicals.

Aitken, M.D.; Grimberg, S.J.; Nagel, J.; Nagel, R.D.; Stringfellow, W.T.



Polycyclic aromatic compounds (PAHs and oxygenated PAHs) and trace metals in fish species from Ghana (West Africa): bioaccumulation and health risk assessment.  


We report the concentrations of 28 PAHs, 15 oxygenated PAHs (OPAHs) and 11 trace metals/metalloids (As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Se, and Zn) in muscle and gut+gill tissues of demersal fishes (Drapane africana, Cynoglossus senegalensis and Pomadasys peroteti) from three locations along the coast of the Gulf of Guinea (Ghana). The concentrations of ?28PAHs in muscle tissues averaged 192ngg(-1) dw (range: 71-481ngg(-1) dw) and were not statistically different between locations. The concentrations of ?28 PAHs were higher in guts+gills than in muscles. The PAH composition pattern was dominated by low molecular weight compounds (naphthalene, alkyl-naphthalenes and phenanthrene). All fish tissues had benzo[a]pyrene concentrations lower than the EU limit for food safety. Excess cancer risk from consumption of some fish was higher than the guideline value of 1×10(-6). The concentrations of ?15 OPAHs in fish muscles averaged 422ngg(-1) dw (range: 28-1715ngg(-1)dw). The ?15 OPAHs/?16 US-EPA PAHs concentration ratio was >1 in 68% of the fish muscles and 100% of guts+gills. The log-transformed concentrations of PAHs and OPAHs in muscles, guts+gills were significantly (p<0.05) correlated with their octanol-water partitioning coefficients, strongly suggesting that equilibrium partitioning from water/sediment into fish tissue was the main mechanism of bioaccumulation. The trace metal concentrations in the fish tissues were in the medium range when compared to fish from other parts of the world. The concentrations of some trace metals (Cd, Cu, Fe, Mn, Zn) were higher in guts+gills than in muscle tissues. The target hazard quotients for metals were<1 and did not indicate a danger to the local population. We conclude that the health risk arising from the consumption of the studied fish (due to their PAHs and trace metals content) is minimal. PMID:24486971

Bandowe, Benjamin A Musa; Bigalke, Moritz; Boamah, Linda; Nyarko, Elvis; Saalia, Firibu Kwesi; Wilcke, Wolfgang



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

NASA Astrophysics Data System (ADS)

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 PAHs in the morning, when there is more vehicular traffic. The time series of PAHs also exhibit synchronized peaks of PAHs and DC that correspond to hours of traffic which shows the relationship of PAHs with DC. However, correlations of PAHs with DC show a relatively strong scattering suggesting that aerosols are a mixture of particles of different sources and different ages. Throughout the day is observed the aging of primary combustion particles due to the secondary aerosols coating. This coating may prolong the life time of the PAHs in the atmosphere. Also occurs a decrease in the ratio PAHs / DC during the day. Low ratios indicate the abundance of large particles, whereas high ratios indicate abundance dominated by small particle emissions from diesel engines. The resulting correlations show a significant linear trend evolution of PAHs with NOx, indicating that the PAHs are associated with the combustion of diesel, and a linear trend of PAHs with DC for each type of aerosol combustion, while the correlation of PAHs with CO results in an exponential trend which implies that PAHs are related to the combustion of diesel.

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



Spectroscopy and Narrow Band Imaging of PAHs in HII regions and Planetary Nebulae using FLITECAM  

NASA Astrophysics Data System (ADS)

FLITECAM, the first light test camera being developed for NASA's SOFIA aircraft has been used successfully on the Shane 120 inch telescope at Lick Observatory on six occasions, most recently to commission the grism spectroscopy mode. Utilizing 3 direct-ruled KRS-5 grisms, this mode provides R 1700 spectroscopy in 9 bands from 1-5 microns for a 1 arcsec slit (2.4 pixels). One of the spectral bands covers the 3.3 micron PAH emission feature. Although difficult to observe from the ground, we have used this emission feature to survey a sample of young and proto-planetary nebulae, carbon stars, and HII regions. On extended sources we also used FLITECAM's wide-field imaging mode to construct narrow-band images centered on and near the 3.3 micron PAH feature. These maps were then used to position FLITECAM's 1 x 60 arcsecond slit on the most prominent areas of PAH emission. The planetary nebulae surveyed with FLITECAM were selected from lists of IRAS and ISO targets. All the selected nebulae have C/O ratios larger than 1, and several targets were known to exhibit PAH emission at longer wavelengths. NGC 7027, a young and highly energetic planetary nebula exhibits the strongest 3.3 micron PAH emission in our survey, as well as strong atomic line emission. Our current sample of 21 PNs shows 12 with PAH emission. None of the carbon stars in our survey showed either PAH or atomic line emission. Narrow band images of the star-forming regions S106, the Orion bar and NGC 1333 reveal clumps of PAH emission. In S106 and Orion the position of peak PAH emission is clearly offset from the position of peak Brackett-Gamma emission by several arcseconds. E. Smith is funded by a NASA GSRP fellowship. Funding for FLITECAM is provided by USRA and UCLA.

Smith, E. C. D.; McLean, I. S.



Removal of PAHs from highly contaminated soils found at prior manufactured gas operations.  


Removal of PAHs from highly contaminated soil found at a manufactured gas site was evaluated using solvent washing with mixed solvents. The following solvents were considered as water miscible co-solvents in mixed solvents: ethanol, 2-propanol, acetone, and 1-pentanol. In batch solvent extraction of soil, ethanol and 2-propanol were selected as primary components of mixed solvents in addition to 1-pentanol. Using ternary solutions containing either ethanol or 2-propanol with a volume fraction of 1-pentanol ranging from 5 to 25% and a water volume fraction ranging from 5 to 30%, ethanol was more effective than 2-propanol in extracting PAHs from soil. A solvent mixture of 5% 1-pentanol, 10% water and 85% ethanol was selected as the extraction solvent. Using a 1g:4ml soil:solvent extraction ratio, extraction kinetics showed that from 65 to 90% of the extractable PAHs were removed within an hour of contact between soil and solvent. Using this 1g:4ml extraction ratio, PAHs were removed in a three-stage cross-current solvent washing process where the same batch of soil was extracted with clean solvent for 1h in each stage. PAH removals in three-stage cross-current solvent washing were comparable to PAH removals obtained with Soxhlet extraction. PMID:11080576

Khodadoust, A P; Bagchi, R; Suidan, M T; Brenner, R C; Sellers, N G



Polycyclic aromatic hydrocarbons (PAHs) and carbonyl compounds in urban atmosphere of Hong Kong  

NASA Astrophysics Data System (ADS)

Polycyclic aromatic hydrocarbons (PAHs) and carbonyls compounds are becoming a major component of atmospheric toxic air pollutants (TAPs) in Hong Kong. Many studies in Hong Kong show that traffic emission is one of the most significant contributors in urban area of Hong Kong. A twelve months monitoring program for PAHs and carbonyl compounds started on 10 April 1999 including a two weeks intensive sampling in winter had been performed at a roadside urban station at Hong Kong Polytechnic University in order to determine the monthly and seasonal variations of PAHs and carbonyl concentrations. The objective of this study is to characterize the roadside concentrations of selected TAPs (PAHs and carbonyl compounds) and to compare with the long-term compliance monitoring data acquired by Hong Kong Environmental Protection Department (EPD). Monthly variations, seasonal variations and winter/summer ratios at the monitoring station are discussed.

Lee, S. C.; Ho, K. F.; Chan, L. Y.; Zielinska, Barbara; Chow, Judith C.



EPA Science Inventory

PAHs in the Lake Michigan Aquatic Ecosystem. Fernandez, JD*, Burkhard, LP, Cook, PM, Nichols, JW, Mid-Continent Ecology Division, U.S. EPA, Duluth MN. In this study, we are investigating the accumulation of PAHs in the Lake Michigan food web. Focusing on EPA's 16 "Priority Po...


Pavement Sealcoat, PAHs, and the Environment  

NASA Astrophysics Data System (ADS)

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.

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



Desorption of polycyclic aromatic hydrocarbons (PAH`s) from calcite and quartz sediments to seawater  

SciTech Connect

Polycyclic aromatic hydrocarbons (PAH`s) are ubiquitous hydrophobic organic pollutants in the marine environment. Many of the PAM`s are classified as possible carcinogens or mutagens, therefore they are of considerable concern to human and environmental health. The highest concentrations are found in coastal regions due to anthropogenic activities including oil spills, tanker operations, incomplete fossil fuel combustion and runoff. The sources and distribution of PAM`s in sediments are fairly well known, while the fate and transport of PAH`s in the marine environment are less known. Desorption is an important factor influencing the fate and transport of hydrophobic molecules at the seawater/sediment interface. The desorption of PAH`s from contaminated marine sediments to the water column/pore water affects the availability of the pollutant to biota. The sorption of PAH`s is determined in part by the organic carbon content of the sediments. The presence of dissolved organic carbon (DOC) in the water column may also influence sorption of hydrophobic molecules. DOC may play an important role in the fate and transport of PAH`s in coastal regions where DOC concentrations are highest. This study presents the results of the desorption of nine PAHs from sediments to seawater. Factors observed included carbon content of sediments, sediment mineralogy, fulvic acid addition to seawater and dissolved organic carbon in seawater.

Sutton, P.L.; Van Vleet, E.S. [Univ. of South Florida, St. Petersburg, FL (United States)



Cut-Off Values of Visceral Fat Area and Waist-to-Height Ratio: Diagnostic Criteria for Obesity-Related Disorders in Korean Children and Adolescents  

PubMed Central

Purpose The aim of this study was to study the appropriate cut-off value of visceral fat area (VFA) and waist-to-height ratio (WTHR) which increase the risk of obesity-related disorders and to validate the diagnostic criteria of abdominal obesity and metabolic syndrome in Korean children and adolescents. Materials and Methods A total 314 subjects (131 boys and 183 girls) were included in this study. The subjects were selected from Korean children and adolescents who visited three University hospitals in Seoul and Uijeongbu from January 1999 to December 2009. All patients underwent computed tomography to measure VFA. Results The cut-off value of VFA associated with an increase risk of obesity-related disorder, according to the receiver operating characteristics curve, was 68.57 cm2 (sensitivity 59.8%, specificity 76.6%, p=0.01) for age between 10 to 15 years, and 71.10 cm2 (sensitivity 72.3%, specificity 76.5%, p<0.001) for age between 16 to 18 years. By simple regression analysis, the WTHR corresponding to a VFA of 68.57 cm2 was 0.54 for boys and 0.61 for girls, and the WTHR corresponding to a VFA of 71.10 cm2 was 0.51 for boys and 0.56 for girls (p=0.004 for boys, p<0.001 for girls). Conclusion Based on the results of this study, VFA which increases the risk of obesity-related disorders was 68.57 cm2 and the WTHR corresponding to this VFA was 0.54 for boys and 0.61 for girls age between 10-15 years, 71.70 cm2 and the WTHR 0.51 for boys and 0.56 for girls age between 16-18 years. For appropriate diagnostic criteria of abdominal obesity and obesity-related disorders in Korean children and adolescents, further studies are required. PMID:22187238

Lee, Kang-Kon; Park, Hye-Soon



Infrared fluorescence from PAHs in the laboratory  

NASA Technical Reports Server (NTRS)

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.

Cherchneff, Isabelle; Barker, John R.



Are PAH molecules the carriers of Unidentified Infrared Emission bands?  

NASA Astrophysics Data System (ADS)

Polycyclic aromatic hydrocarbon (PAH) molecules are widely considered as 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 result 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 suggest that a general match between astronomical spectra and those of PAH mixtures does not necessarily provide definitive support for the PAH hypothesis.

Kwok, Sun; Zhang, Yong



PAHs and nitrated PAHs in air of five European countries determined using SPMDs as passive samplers  

NASA Astrophysics Data System (ADS)

The gas phase polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs in the atmosphere of five European countries (Austria, the Czech Republic, Poland, Slovakia and Sweden) were measured simultaneously during two 21-day passive sampling campaigns using semipermeable membrane devices (SPMDs). SPMD samplers, consisting of a pair of SPMDs covered by a metal umbrella, were deployed at 40 locations ranging from remote and rural to urban and industrial, at a similar time during each of the two sampling campaigns (autumn 1999, except in Poland, winter 1999, and summer 2000). The total amounts of PAHs and nitro-PAHs found in the SPMDs ranged between 5.0-1.2×10 3 and 1.1×10 -3-4.0 ng SPMD -1 day -1, respectively. The measured environmental sampling conditions were similar between sites and, thus, the variations in the SPMD data reflected the spatial differences in gas phase concentrations of nitro-PAHs and PAHs within and between countries. The gas phase concentrations of nitro-PAHs and PAHs found in East Europe (Slovakia, the Czech Republic and Poland 1999) were 10 times higher than those measured in Sweden, Austria and Poland in 2000. In each country, the levels of PAHs and nitro-PAHs differed by one-three orders of magnitudes amongst sampling sites. The highest within-country spatial differences were found in Poland where levels of PAHs and nitro-PAHs were about one and two orders of magnitudes, respectively, higher in winter 1999 than in summer 2000, probably due to increasing emissions of coal combustion for residential heating. Differences in PAH-patterns between sites were visualized by the multivariate projection method, principal component analysis (PCA). However, no specific source patterns were found, probably since imissions rather than emissions were measured, so the PAHs detected at many sites originated from multiple sources.

Söderström, Hanna; Hajšlová, Jana; Kocourek, Vladimir; Siegmund, Barbara; Kocan, Anton; Obiedzinski, Mieczys?aw W.; Tysklind, Mats; Bergqvist, Per-Anders


Theoretical evaluation of PAH dication properties  

NASA Astrophysics Data System (ADS)

Aims:We present a systematic, theoretical study of 40 polycyclic aromatic hydrocarbon dications (PAHs++) containing up to 66 carbon atoms. Methods: We performed our calculations using well-established quantum-chemical techniques in the framework of (i) the density functional theory (DFT) to obtain the electronic ground-state properties and of (ii) the time-dependent DFT (TD-DFT) to evaluate the excited-state properties. Results: For each PAH++ considered, we computed the absolute visible-UV photo-absorption cross-section up to about 30 eV. We also evaluated their vibrational properties and compared them to those of the corresponding neutral and singly-ionised species. We estimated the adiabatic and vertical second ionisation energy ? I through total energy differences. Conclusions: .The ? I values obtained fall in the energy range 8-13 eV, confirming that PAHs could reach the doubly-ionised state in HI regions. The total integrated IR absorption cross-sections show a marked increase upon ionisation, being on the average about two and five times larger for PAHs++ than for PAHs+ and PAHs, respectively. The visible-UV photo-absorption cross-sections for the 0, +1 and +2 charge-states show comparable features but PAHs++ are found to absorb slightly less than their parent neutral and singly ionised species between ~7 and ~12 eV. Combining these pieces of information, we found that PAHs++ should actually be stabler against photodissociation than PAHs and PAHs^+, if dissociation thresholds are nearly unchanged by ionisation. Appendix A is only available in electronic form at

Malloci, G.; Joblin, C.; Mulas, G.



[Diagnostic accuracy].  


Clinical decision making while making a diagnosis is based on pre-test probability evaluation, a decision whether further tests are needed, and post-test probability evaluation based on test results. The add value of the test is the increase in probability, which depends on its diagnostic accuracy. Some measures of diagnostic accuracy are sensitivity, specificity, positive predictive value, negative predictive value, likelihood ratio, area under the curve, Youden index, and diagnostic odds ratio. ROC curve is the most efficient way of graphic description of the relationship between sensitivity and specificity. Diagnostic accuracy of a test is evaluated in a cross-sectional study on a group of individuals subjected simultaneously to the index test and the gold standard. All parameters of diagnostic accuracy are very sensitive to the study design, therefore it is of utmost importance to perform and write a study to adhere to the proposed STARD standards. This lecture gives an insight into the basics of biostatistical terminology from the field of diagnostic accuracy. PMID:16526310

Simundi?, Ana-Maria



Biomonitoring airborne parent and alkylated three-ring PAHs in the Greater Cologne Conurbation II: regional distribution patterns.  


The spatial distribution of an important air pollutant class, three-ring polycyclic aromatic hydrocarbons and their derivatives (PAH-3), has been monitored for the Greater Cologne Conurbation (GCC) using pine needle as passive samplers. The GCC comprises one of the most heavily populated, trafficked, and industrialized regions in Germany. Here, 71 locations covering 3600 km(2) were sampled and, for the first time, isopleths maps constructed to investigate the regional variability in PAH-3 concentration and composition. The highest PAH-3 loads on needles (1000-1500 ng g(-1)) were detected downwind of three lignite fuelled power plants, followed by Cologne City (600-700 ng g(-1)) and smaller towns (400-600 ng g(-1)), whereas rural and forest regions yielded PAH-3 loads of 60-300 ng g(-1). PAH-3 ratios facilitated source reconciliation, with high dibenzothiophene versus retene values indicating lignite combustion and high 9/(9+1)-methylphenanthrene ratios depicting traffic emissions in inner cities. PAH-3 ratios depended on topography and outlined the heavily industrialized Rhine Valley, demonstrating atmospheric dispersal of PAH-3. PMID:19157662

Lehndorff, E; Schwark, L



Influence and interactions of multi-factors on the bioavailability of PAHs in compost amended contaminated soils.  


Compost amendment to contaminated soils is a potential approach for waste recycling and soil remediation. The relative importance and interactions of multiple factors on PAH bioavailability in soils were investigated using conjoint analysis and five-way analysis of variance. Results indicated that soil type and contact time were the two most significant factors influencing the PAH bioavailability in amended soils. The other two factors (compost type and ratio of compost addition) were less important but their interactions with other factors were significant. Specifically the 4-factor interactions showed that compost addition stimulated the degradation of high molecular PAHs at the initial stage (3 month) by enhancing the competitive sorption within PAH groups. Such findings suggest that a realistic decision-making towards hydrocarbon bioavailability assessment should consider interactions among various factors. Further to this, this study demonstrated that compost amendment can enhance the removal of recalcitrant hydrocarbons such as PAHs in contaminated soils. PMID:24875869

Wu, Guozhong; Li, Xingang; Kechavarzi, Cédric; Sakrabani, Ruben; Sui, Hong; Coulon, Frédéric



Determining air-water exchange, spatial and temporal trends of freely dissolved PAHs in an urban estuary using passive polyethylene samplers.  


Passive polyethylene (PE) samplers were deployed at six locations within Narragansett Bay (RI, USA) to determine sources and trends of freely dissolved and gas-phase polycyclic aromatic hydrocarbons (PAHs) from May to November 2006. Freely dissolved aqueous concentrations of PAHs were dominated by fluoranthene, pyrene, and phenanthrene, at concentrations ranging from tens to thousands of pg/L. These were also the dominant PAHs in the gas phase, at hundreds to thousands of pg/m3. All stations mostly followed the same temporal trends, with highest concentrations (up to 7300 pg/L for sum PAHs) during the second of 11 deployments, coinciding with a major rainstorm. Strong correlations of sum PAHs with river flows and wastewater treatment plant discharges highlighted the importance of rainfall in mobilizing PAHs from a combination of runoff and atmospheric washout. PAH concentrations declined through consecutive deployments III to V, which could be explained by an exponential decay due to flushing with cleaner ocean water during tides. The estimated residence time (tres) of the PAH pulse was 24 days, close to an earlier estimate of tres of 26 days for freshwater in the Bay. Air-water exchange gradients indicated net volatilization of most PAHs closest to Providence. Further south in the Bay, gradients had changed to mostly net uptake of the more volatile PAHs, but net volatilization for the less volatile PAHs. Based on characteristic PAH ratios, freely dissolved PAHs at most sites originated from the combustion of fossil fuels; only two sites were at times affected by fuel spill-derived PAHs. PMID:21351793

Lohmann, Rainer; Dapsis, Meredith; Morgan, Eric J; Dekany, Victoria; Luey, Pamela J



Distribution patterns and sources of metals and PAHs in an intensely urbanized area: The Acerra-Pomigliano-Marigliano conurbation (Italy)  

NASA Astrophysics Data System (ADS)

The main objective of the URGE (URban GEochemistry) project is to define, map and interpretate the geochemical baseline patterns of potentially harmful elements and compounds in the soils of 12 european urban areas using shared procedures for both sampling and analytical techniques. In Italy, in the framework of the URGE project, the north-eastern sector of the Napoli metropolitan area, namely the Acerra-Pomigliano-Marigliano conurbation, has undergone a geochemical characterization based on 145 soil samples collected over an area of 90 sq km. This area has been selected on the basis of the results obtained from previous regional studies [1, 2, 3] and because of the presence on its territory of an historical industrial settlement (formerly devoted to plastic materials and synthetic fibres production) which was partly dismantled and party converted to a power plant fuelled by palm oil. Furthermore, in March 2009 also an incinerator came into operation in the northern sector of the study area. The main objective of the study carried out for the Acerra-Pomigliano-Marigliano conurbation was to define the local geochemical baselines for both 53 elements (among which the toxic ones) and some organic compounds, including PAHs and OCPs. The study also aimed at supporting epidemiological researches at local scale and at establishing a record of the actual environmental conditions to evaluate the future impact of the incinerator on both the territory and the public health. Results obtained showed that Pb, Zn and V exceed the trigger limits established by the Italian Environmental law (D.Lgs. 152/2006) especially in correspondence with the most densely populated areas of the conurbation and where the traffic load is higher (Road junctions and fast lanes). Furthermore, most of the soils collected in the surroundings of the urbanized areas resulted to be generally enriched in Cu, Co, Cd, Be, Ni and P suggesting the presence of a relevant influence on their chemistry of an agricultural intensive land use. PAHs distribution pattern showed anomalous values across the whole study area. Especially, Benzo[a]pyrene values exceeds the trigger limits established by the Italian Environmental law (D.Lgs. 152/2006) in most of the analyzed soils and the diagnostic ratios calculated among several PAHs compounds suggested that the biomass burning in the rural sector of the study area could be a relevant source of pollution. The palm oil fuelled power plant in the northern sector of Acerra could not be excluded as a source of PAHs in the environment. [1] Albanese et al (2007) JGE 93, 21-34. [2] Cicchella et al (2008) GEEA 8 (1), 19-29. [3] De Vivo et al (2006) Aracne Editrice, Roma. 324 pp.

Albanese, Stefano; Lima, Annamaria; Rezza, Carmela; Ferullo, Giampiero; De Vivo, Benedetto; Chen, Wei; Qi, Shihua



Composition, sources, and potential toxicology of polycyclic aromatic hydrocarbons (PAHs) in agricultural soils in Liaoning, People's Republic of China.  


Surface soil (0-20 cm) samples (n?=?143) were collected from vegetable, maize, and paddy farmland used for commercial crops in Liaoning, China. Sixteen priority polycyclic aromatic hydrocarbons (PAHs) listed in US Environmental Protection Agency were analyzed by high-performance liquid chromatography using a fluorescence detector. The soil concentrations of the 16 PAH ranged from 50 to 3,309 ng/g with a mean of 388 ng/g. The highest concentration of total PAHs found in soil of the vegetable farmland was 448 ng/g in average, followed by maize and paddy with total PAHs of 391 and 331 ng/g, respectively. Generally, the low molecular weight PAHs were more predominant than the high molecular weight PAHs in most of the soils. The evaluation of soil PAH contamination based on the Canadian criterion indicated that only naphthalene, phenanthrene, and pyrene were over the target values in several sampling sites. Isomer pair ratios and principal component analysis indicated that biomass and coal combustion were the main sources of PAHs in this area. And the average value of total B[a]Peq concentration in vegetable soils was higher than paddy and maize soils. We suggest that biomass burning should be abolished and commercial farming should be carried out far from the highways to ensure the safety of food products derived from commercial farming. PMID:22707148

Cao, Xiu Feng; Liu, Miao; Song, Yu Fang; Ackland, M Leigh



Polycyclic aromatic hydrocarbons (PAHs) in sea sediments of the Turkish Mediterranean coast, composition and sources.  


The concentrations of polycyclic aromatic hydrocarbons (PAHs) were determined in 25 surface sediment samples from five sites located at Oludeniz Lagoon of the Turkish Mediterranean coast. The total concentration of the PAHs (1.85?±?1.39 mg/kg) was lower than the sediments from highly urbanized areas, while it was comparable with the sediments from similar locations. Acenaphthene and chrysene were dominant ones with the concentrations of 0.620 and 0.515 mg/kg, respectively. The isomeric ratios indicated that combustion is the predominant source of PAHs in the sediments. Factor analysis solution supports the same finding with three major factors accounting for 71.7 % of the variability in the data. Factor 1 with 43.4 % of the total variance identified as a pyrogenic source (coal combustion; 4 rings PAH and traffic related pollution; 5-6 rings PAHs). Factor 2 (explains 39 % of the total variance) represents PAHs originating from traffic, and factor 3 (explains 12 % of the total variance) represents petrogenic source. Our results suggest that combustion of fossil fuels affects most of the points, followed by combustion of biomass and human activity. PMID:25280504

Tuncel, Semra G; Topal, Tansel



Sedimentary records of PAHs in a sediment core from tidal flat of Haizhou Bay, China.  


The concentrations and depositional fluxes of polycyclic aromatic hydrocarbons (PAHs) were investigated in a dated sediment core collected from a tidal flat in Haizhou Bay, China. The USEPA's 16 priority PAH concentrations ranged from 72.51 ng g(-1) dw in 1969 to 805.21 ng g(-1) dw in 2010, while the deposition fluxes were in the range of 102.36-861.02 ng cm(-2) yr(-1). The PAH concentrations and fluxes changed dramatically with depth, suggesting changes in energy usage and corresponding closely with the historical economic development of eastern China. The levels of PAHs slightly increased from the late 1970s, following China's "Reform and Open" policy of 1978; however, a drastic increase in the concentration of PAHs observed in 1990 was indicative of the rapid growth in coal and petroleum incomplete combustion byproducts, which was associated with the increase in economic development in this area. Furthermore, isomer ratio analysis and principle component analysis revealed the main anthropogenic pyrolytic source that causes PAH contamination in the coastal sediment. PMID:23500827

Zhang, Rui; Zhang, Fan; Zhang, Tian-Cheng



Occurrence, distribution, environmental risk assessment and source apportionment of polycyclic aromatic hydrocarbons (PAHs) in water and sediments of the Liaohe River Basin, China.  


The occurrence and distribution of polycyclic aromatic hydrocarbons (PAHs) were investigated in water and sediments in Liaohe River Basin. The total PAH concentrations ranged from 111.9 to 2,931.6 ng/L in water and from 92.2 to 295,635.2 ng/g dry weight (dw) in sediments. The PAHs in water were dominated by 2-, 3- and 4-ring PAHs, which accounted for 42.8 %, 39.4 % and 14.2 % of the total PAHs, respectively, while in sediment PAHs were dominated by 3-, 4- and 5-ring PAHs, which accounted for 26.5 %, 44.2 % and 17.4 % of the total PAHs, respectively. The benzo[a]pyrene equivalents for water samples showed that in 37 out of 50 sites the values were greater than the national standard, and the environmental risk assessment indicated that high environmental risk of PAHs existed in sediments. Using the molecular ratio method for the source identification it was concluded that PAHs were determined to be from mixed sources (petroleum and combustion) in Liaohe River system and combustion sources in Daliao River system. PMID:25323038

Bai, Yangwei; Meng, Wei; Xu, Jian; Zhang, Yuan; Guo, Changsheng; Lv, Jiapei; Wan, Jun



Properties of Polycyclic Aromatic Hydrocarbons in the Northwest Photon Dominated Region of NGC 7023. II. Traditional PAH Analysis Using k-means as a Visualization Tool  

NASA Astrophysics Data System (ADS)

Polycyclic aromatic hydrocarbon (PAH) emission in the Spitzer-IRS spectral map of the northwest photon dominated region (PDR) in NGC 7023 is analyzed using the "traditional" approach in which the PAH bands and plateaus between 5.2-19.5 ?m are isolated by subtracting the underlying continuum and removing H2 emission lines. The spectra are organized into seven spectroscopic bins by using k-means clustering. Each cluster corresponds to, and reveals, a morphological zone within NGC 7023. The zones self-organize parallel to the well-defined PDR front that coincides with an increase in intensity of the H2 emission lines. PAH band profiles and integrated strengths are measured, classified, and mapped. The morphological zones revealed by the k-means clustering provides deeper insight into the conditions that drive variations in band strength ratios and evolution of the PAH population that otherwise would be lost. For example, certain band-band relations are bifurcated, revealing two limiting cases; one associated with the PDR, the other with the diffuse medium. Traditionally, PAH band strength ratios are used to gain insight into the properties of the emitting PAH population, i.e., charge, size, structure, and composition. Insights inferred from this work are compared and contrasted to those from Boersma et al. (first paper in this series), where the PAH emission in NGC 7023 is decomposed exclusively using the PAH spectra and tools made available through the NASA Ames PAH IR Spectroscopic Database.

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



PAHs and the Chemistry of the ISM  

NASA Astrophysics Data System (ADS)

This review describes five categories of the reactions of polycyclic aromatic hydrocarbons, including photochemistry, electron attachment/detachment, recombination processes, radical reactions, and ion-neutral chemistry. For each class of reaction, an overview of the studies and their general results are presented, as well as references to the literature. The thermochemistry of PAHs and relevant species is described, including bond dissociation energies, ionization energies, electron affinities, basicities, acidities, and the interrelationships of these quantities. Modeling of the chemistry of PAHs and their ions is discussed for both diffuse and dark clouds. The role of PAH cations in the catalytic formation of molecular hydrogen is considered. Finally, this review concludes with a discussion of current challenges in the chemical characterization of PAHs, and a perspective for future studies.

Bierbaum, V. M.; Le Page, V.; Snow, T. P.



Amphibian responses to photoinduced toxicity of PAHs  

SciTech Connect

Amphibians are essential components of many ecosystems, yet little information exists on their sensitivity to environmental stressors. Recent evidence shows amphibian diversity is declining. Others have suggested this decline is a result of increasing ultraviolet (UV) light levels. Polycyclic aromatic hydrocarbons (PAHs) are widespread pollutants in the aquatic environment and their toxicity is increased in the presence of UV light. Embryos of two frogs (Rana pipiens and Xenopus laevis) were exposed to a PAH, fluoranthene, to evaluate amphibian responses to this common contaminant in the presence of sunlight. Hatching rate and development were measured in field and laboratory exposures at multiple concentrations and varying UV intensities. Hatching rate was relatively unaffected, while newly hatched larvae were sensitive to low (ug/L) concentrations. Response was related to both PAH concentration and UV intensity. Results suggest that PAH contamination in the aquatic environment may contribute to declines in amphibian populations.

Hatch, A.C.; Burton, G.A. Jr. [Wright State Univ., Dayton, OH (United States). Biological Sciences Dept.



PAH in the laboratory and interstellar space  

NASA Technical Reports Server (NTRS)

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.

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




EPA Science Inventory

Personal exposures to airborne particulate polycyclic aromatic hydrocarbons (PAHs) were studied in several populations in the US, Japan, and Czech Republic. Personal exposure monitors, developed for human exposure biomonitoring studies were used to collect fine particles (...


PAHs in soils: Sorption versus degradation - elucidation of rate-limiting processes  

NASA Astrophysics Data System (ADS)

Polycyclic aromatic hydrocarbons (PAHs) belong to the class of persistent organic pollutants, and are of special interest due to their ubiquituous distribution in the environment at relatively high concentrations. Subsequent to their emmission into the environment through incomplete combustion processes of natural and anthropogenic sources (e.g. vulcano eruptions, forest fires, industry, traffic), PAHs can be transported over long distances. Following atmospheric deposition they accumulate in particular in top-soils and have been found to be stable over long periods of time (decades to centuries). Based on that this study targets on the elucidation of the long-term PAH-fate in top-soils by means of degradation experiments under well-controlled laboratory conditions with well mixed batch experiments at a water to solids ratio 10:1. From a rural site in the Black Forest Mountains, Germany, top-soil samples were taken, which contains approximately 7-8 mg ?18 PAHs per kg soil. This soil was sieved through 2 mm to sort out stones, roots- and leaf-parts and homogenised afterwards. Within the first month of incubation a depletion of native PAHs were observed. However, an exhaustive sequential extraction using accelerated solvent extraction with 3 cycles of acteone and 4 cycles of toluene (100 bar pressure, 10 min static time, 100°C and 150°C respectively) revealed a reduced extractability of PAHs subsequent to incubation. In order to stimulate PAH degradation a second experiment with a higher water to solid ratio (1000:1) was carried out, and phenanthrene was spiked to the water phase of this set up. Results revealed a reduction of phenanthrene concentration more likely to be due to sorption rather than degradation. The set up was changed to aqueous soil solutions without soil in the batch and spiked again with phenanthrene. Degradation of phenanthrene occurred within 10 days in these batches. The experiments show that the microorganisms present in the Black Forest soil are capable to degrade PAHs. Nevertheless strong sorption and high organic carbon content in this soil prevent these microorganisms from degrading the native PAHs. The results were implemented into a mass balance model considering both, sorption and degradation. The calculations were conducted with first order rate constant ? taken from the non-soil-containing experiment, and revealed a half-life of phenanthrene up to almost one century. Keywords: PAH, degradation, sorption

Herklotz, Ilka; Gocht, Tilman; Grathwohl, Peter



PAH Emission in the Orion Bar  

NASA Technical Reports Server (NTRS)

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.

Bregman, Jesse; Sloan, G. C.



PAH emission from the industrial boilers  

Microsoft Academic Search

Polycyclic aromatic hydrocarbons (PAHs) emitted from 25 industrial boilers were investigated. The fuels used for these 25 boilers included 21 heavy oil, two diesel, a co-combustion of heavy oil and natural gas (HO+NG) and a co-combustion of coke oven gas and blast furnace gas (COG+BFG) boilers. PAH samples from the stack flue gas (gas and particle phases) of these 25

Chun-Teh Li; Hsiao-Hsuan Mi; Wen-Jhy Lee; Wen-Chun You; Ya-Fen Wang



An Investigation into PAH Destruction in Nearby Supernova Remnants, North Polar Spur and Cygnus Loop  

NASA Astrophysics Data System (ADS)

Our goal in conducting this research was to look at the polycyclic aromatic hydrocarbon (PAH)/large dust grain emission intensity ratio in nearby supernova remnants to find evidence for selective PAH destruction by hot gas and high velocity shock waves within these regions, as predicted by the models of Arendt et al. (2010) and Micelotta et al. (2010a,b). Two supernova remnants were studied- the North Polar Spur (NPS) and the Cygnus Loop. The data for PAHs were obtained from the WISE W3 12 micron all-sky map processed by Meisner & Finkbeiner (2014), and the data for the larger grains come from the IRAS 100 micron all-sky map processed by Schlegel, Finkbeiner & Davis (1998). After obtaining a control PAH/large grain intensity ratio of ~2.8 (DN/px)/(MJy/sr) from two high latitude clouds, MBM 30 and MBM 32, we found that the intensity ratios across the NPS and Cygnus Loop were not far off- ~2.7 (DN/px)/(MJy/sr) and ~3.1 (DN/px)/(MJy/sr), respectively- showing no evidence of selective large-scale PAH destruction in supernova remnants. The individual intensities for both PAHs and large grains do decrease inside the Cygnus Loop, however, suggesting a decrease in abundances of both grain types, which could mean total dust grain destruction with the normal ratios coming from foreground and background dust located in the line of sight of the remnant. In addition, temperature and E(B-V) measurements taken from calibrated IRAS images show that while the dust column density increases in the Eastern Veil of the Cygnus Loop, the dust temperature reaches a local maximum, indicating the heating of large grains by interaction with the hot gas in the remnant. The PAH/large grain ratio in the Eastern Veil does decrease and could be indicative of currently ongoing active grain destruction there, with the PAHs being destroyed on a more rapid timescale than the large grains.We are grateful for financial support from the NSF REU Program grant to the Department of Physics & Astronomy at the University of Toledo.

Burkhart, Sarah M.; Witt, Adolf N.



Spitzer Mid-Infrared Spectroscopy of Infrared Luminous Galaxies at z~2 III: Far-IR to Radio Properties and Optical Spectral Diagnostics  

E-print Network

We present the far-IR, millimeter, and radio photometry as well as optical and near-IR spectroscopy of a sample of 48 z~1-3 Spitzer-selected ULIRGs with IRS mid-IR spectra. Our goals are to compute their bolometric emission, and to determine both the presence and relative strength of their AGN and starburst components. We find that strong-PAH sources tend to have higher 160um and 1.2mm fluxes than weak-PAH sources. The depth of the 9.7um silicate feature does not affect MAMBO detectability. We fit the far-IR SEDs of our sample and find an average ~7x10^{12}Lsun for our z>1.5 sources. Spectral decomposition suggests that strong-PAH sources typically have ~20-30% AGN fractions. Weak-PAH sources by contrast tend to have >~70% AGN fractions, with a few sources having comparable contributions of AGN and starbursts. The optical line diagnostics support the presence of AGN in the bulk of the weak-PAH sources. With one exception, our sources are narrow-line sources, show no obvious correspondence between the optical extinction and the silicate feature depth, and, in two cases, show evidence for outflows. Radio AGN are present in both strong-PAH and weak-PAH sources. This is supported by our sample's far-IR-to-radio ratios (q) being consistently below the average value of 2.34 for local star-forming galaxies. We use survival analysis to include the lower-limits given by the radio-undetected sources, arriving at =2.07+/-0.01 for our z>1.5 sample. In total, radio and, where available, optical line diagnostics support the presence of AGN in 57% of the z>1.5 sources, independent of IR-based diagnostics. For higher-z sources, the AGN luminosities alone are estimated to be >10^{12}Lsun, which, supported by the [OIII] luminosities, implies that the bulk of our sources host obscured quasars.

Anna Sajina; Lin Yan; Dieter Lutz; Aaron Steffen; George Helou; Minh Huynh; David Frayer; Philip Choi; Linda Tacconi; Kalliopi Dasyra



Decision Making for Borderline Cases in Pass/Fail Clinical Anatomy Courses: The Practical Value of the Standard Error of Measurement and Likelihood Ratio in a Diagnostic Test  

ERIC Educational Resources Information Center

Several studies have shown that the standard error of measurement (SEM) can be used as an additional “safety net” to reduce the frequency of false-positive or false-negative student grading classifications. Practical examinations in clinical anatomy are often used as diagnostic tests to admit students to course final examinations. The aim of this…

Severo, Milton; Silva-Pereira, Fernanda; Ferreira, Maria Amelia



Emissions of gas- and particle-phase polycyclic aromatic hydrocarbons (PAHs) in the Shing Mun Tunnel, Hong Kong  

NASA Astrophysics Data System (ADS)

Real-world vehicle emission factors for seventeen gas and particulate polycyclic aromatic hydrocarbons (PAHs) were quantified in the Shing Mun Tunnel, Hong Kong during summer and winter 2003. Naphthalene, acenaphthylene, and acenaphthene were the most abundant gas PAHs while fluoranthene and pyrene were the most abundant in the particle phase. Most (98%) of the gas PAHs consisted of two- and three-aromatic rings whereas most of the particle-phase PAHs were in four- (˜60%) and five-ring (˜17%) for fresh exhaust emissions. Average emission factors for the gas- and particle PAHs were 950-2564 ?g veh -1 km -1 and 22-354 ?g veh -1 km -1, respectively. Good correlations were found between diesel markers (fluoranthene and pyrene; 0.85) and gasoline markers (benzo[ghi]perylene and indeno[1,2,3-cd]pyrene; 0.96). Higher PAH emission factors were associated with a higher fraction of diesel-fueled vehicles (DV) passing through the tunnel. Separate emission factors were determined from diesel and non-diesel exhaust by the regression intercept method. The average PAH emission factor (i.e., sum of gas and particle phases) from DV (3085 ± 1058 ?g veh -1 km -1) was ˜5 times higher than that from non-diesel-fueled vehicles (NDV, 566 ± 428 ?g veh -1 km -1). Ratios of DV to NDV emission factors were high for diesel markers (>24); and low for gasoline markers (<0.4).

Ho, K. F.; Ho, Steven Sai Hang; Lee, S. C.; Cheng, Y.; Chow, Judith C.; Watson, John G.; Louie, P. K. K.; Tian, Linwei



Sedimentary record of PAHs in the Barigui River and its relation to the socioeconomic development of Curitiba, Brazil.  


Concentrations of polycyclic aromatic hydrocarbons (PAHs) were determined in a sediment core collected from the Barigui River, in Curitiba, South Brazil. The USEPA's 16 priority PAH concentrations ranged from 39ng g(-1) to 2350ng g(-1) of dry sediment over a period that corresponds temporally to between ca. 1855 and 2011. The concentrations and patterns of PAH distribution changed over this time period and may be associated with several episodes in the Curitiba's history. Two major PAHs concentration peaks occurred in approximately 1910 and 1970, which might reflect population increases due to immigration programs in the 1890s and the sudden economic development that occurred in Brazil from 1960 to 1980, "The Economic Miracle Period", respectively. Isomeric ratios revealed that the PAHs had predominantly pyrolytic sources. The population, number of highways and electric energy consumption of Curitiba, as indices of socioeconomic development, were positively correlated with PAH deposition in the sediment core from 1855 to 1970, indicating the influence of socioeconomic development on the environmental load of sedimentary PAHs. PMID:24636886

Machado, Karina S; Figueira, Rubens C L; Côcco, Lilian C; Froehner, Sandro; Fernandes, Cristovão V S; Ferreira, Paulo A L



Emissions of PAHs from indoor crop residue burning in a typical rural stove: Emission factors, size distributions and gas-particle partitioning  

PubMed Central

Indoor combustion of crop residues for cooking or heating is one of the most important emission sources of polycyclic aromatic hydrocarbons (PAHs) in developing countries. However, data on PAH emission factors (EFs) for burning crop residues indoor, particularly those measured in field were scarce, leading to large uncertainties in the emission inventories. In this study, EFs of PAHs for nine commonly used crop residues burnt in a typical Chinese rural cooking stove were measured in simulated kitchen. The measured EFs of total PAHs averaged at 63 ± 37 mg/kg, ranging from 27 to 142 mg/kg, which were higher than those measured in chamber experiments, implying that the laboratory experiment based emission and risk assessment should be carefully reviewed. EFs of gaseous and particulate phase PAHs were 27 ± 13 and 35 ± 23 mg/kg, respectively. Composition profiles and isomer ratios of emitted PAHs were characterized. Stepwise regressions found that modified combustion efficiency and fuel moisture were the most important factors affecting the emissions. 80 ± 6 % of PAHs were associated with PM2.5 and the mass percentage of PAHs in fine particles increased as the molecular weight increased. For freshly emitted PAHs, absorption into organic carbon, rather than adsorption, dominated the gas-particle partitioning. PMID:21247097

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



Vertical distribution of polycyclic aromatic hydrocarbons (PAHs) in Hunpu wastewater-irrigated area in northeast China under different land use patterns.  


The concentrations of polycyclic aromatic hydrocarbons (PAHs) were determined in groundwater and soil profiles from upland field and paddy field in the Hunpu wastewater-irrigated area of northeast China. In the study area, the peak concentrations of total PAHs were within or just below the topsoil, and the contents decline with depth at various trend verified by the Spearman's rank correlation test. The total PAH concentrations in upland soil layers ranged from 46.8 to 2,373.0 microg/kg (dry wt.), while the concentrations in paddy soil layers ranged from 23.1 to 1,179.1 microg/kg (dry wt.). The 16 priority PAHs were all detected in the analyzed soil samples, and naphthalene (Nap), phenanthrene (Phe), fluoranthene (Fla), chrysene (Chr), and benzo[a]pyrene (Bap) were selected for further study in terms of their vertical distributions. The concentrations of both total and individual PAHs in upland soil were generally higher than those in the corresponding layers of paddy soil. The concentrations of total and individual PAH were notably different between the corresponding horizons in upland and paddy soil were probably attribute to the different sources and properties of the PAHs and soil; different methods of soil tillage and plant growing. Special PAH compound ratios, such as phenanthrene/anthracene, fluoranthene/pyrene, LMW/HMW, and parent PAH ratios (Ant/178, Fla/202, BaA/228, and Ilp/276) were used to identify the source of soil PAHs. The data suggests that the possible sources of PAHs in the Hunpu wastewater-irrigation area are the incomplete combustion of coal, petroleum and crude oil, automobile exhausts. These sources lead to pollution of the soil and groundwater by wet/dry deposition and vertical downward migration. PMID:17899417

Xiao, Ru; Du, Xiaoming; He, Xiaozhen; Zhang, Yuejin; Yi, Zhihua; Li, Fasheng



Evaluation of PAH contamination in soil treated with solid by-products from shale pyrolysis.  


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 ?g 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. PMID:25399121

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



Abundances of Neutral and Ionized PAH Along The Lines-of-Sight of Diffuse and Translucent Interstellar Clouds  

NASA Technical Reports Server (NTRS)

The spectra of neutral and ionized PAHs isolated in the gas phase at low temperature have been measured in the laboratory under conditions that mimic interstellar conditions and are compared with a set of astronomical spectra of reddened, early type stars. The comparisons of astronomical and laboratory data provide upper limits for the abundances of neutral PAH molecules and ions along specific lines-of-sight. Something that is not attainable from infrared observations. We present the characteristics of the laboratory facility (COSmIC) that was developed for this study and discuss the findings resulting from the comparison of the laboratory data with high resolution, high S/N ratio astronomical observations. COSmIC combines a supersonic jet expansion with discharge plasma and cavity ringdown spectroscopy and provides experimental conditions that closely mimic the interstellar conditions. The column densities of the individual PAH molecules and ions probed in these surveys are derived from the comparison of the laboratory data with high resolution, high S/N ratio astronomical observations. The comparisons of astronomical and laboratory data lead to clear conclusions regarding the expected abundances for PAHs 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 quantitative searches of PAHs and complex organics in a variety of interstellar and circumstellar environments.

Salama, Farid; Galazutdinov, Gazinur; Krewloski, Jacek; Biennier, Ludovic; Beletsky, Yuri; Song, In-Ok



Polycyclic aromatic hydrocarbons (PAHs) in indoor dust matter of Palermo (Italy) area: Extraction, GC-MS analysis, distribution and sources  

NASA Astrophysics Data System (ADS)

Studies on indoor pollution are important since people spend more than 80% of their time indoor environments. In this work the method for PAHs analysis in indoor dust (used as passive sampler) and the results relative to samples collected in the area of Palermo are reported. Dust samples for analysis were collected from 45 indoor environments. Total PAHs concentrations in indoor dusts ranged from 36 to 34 453 ?g kg -1 d.w. To correlate indoor and outdoor pollution we analyze, also, the particulate matter and PAHs levels samples collected in four stations. The percentage measured in indoor dusts results more low than that found outside. The values of isomeric ratios for the different samples were used to individuate the predominant PAHs sources.

Mannino, Maria Rosaria; Orecchio, Santino



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...


Exposure and Kinetics of Polycyclic Aromatic Hydrocarbons (PAHs) in Cigarette Smokers  

PubMed Central

Study objectives were (1) to investigate the selectivity of polycyclic aromatic hydrocarbon (PAH) metabolites for tobacco smoke exposure, and (2) to determine half-lives of PAH metabolites in smokers. There were 622 participants from the United States (US) and Poland, and of these 70% were smokers. All subjects provided spot urine samples and 125 smokers provided blood samples. Urinary PAH metabolite half-lives were determined in 8 smokers. In controlled hospital studies of 18 smokers, the associations between various measures of nicotine intake and urinary excretion of PAH metabolites were investigated. Plasma nicotine was measured by GC. LC-MS/MS was used to measure the plasma levels of cotinine and trans-3?-hydroxycotinine, and urine levels of nicotine and its metabolites, total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and PAH metabolites (2-naphthol, 1-, 2- and 3-hydroxyfluorenes, 1-, 2-, 3-, and 4-hydroxyphenanthrenes, and 1-hydroxypyrene). Regardless of smoking status, PAH metabolite excretion was higher in Polish subjects than in US subjects (p-values<0.001). 1-Hydroxyfluorene exhibited the greatest difference between smokers and non-smokers, with a 5-fold difference in Polish subjects and a 25-fold difference in US subjects, followed by 3- and 2-hydroxyfluorenes, 2-naphthol and 1-hydroxypyrene. The differences for hydroxyphenanthrenes were small or non-significant. 1-Hydroxyfluorene had the highest correlation with urine nicotine equivalents (r=0.77) and urine NNAL (r=0.64). While the half-lives of PAH metabolites were <10 h in smokers, 1-hydroxyfluorene had the largest ratio of initial to terminal urine concentration (58.4±38.6, mean±SD) after smoking. Receiver Operating Characteristic (ROC) analysis of PAHs among Polish and US subjects further showed that hydroxyfluorenes are most highly discriminative of smokers from nonsmokers followed by 2-naphthol and 1-hydroxypyrene. In conclusion, hydroxyfluorenes, particularly 1-hydroxyfluorene, and 2-naphthol are more selective of tobacco smoke than 1-hydroxypyrene and hydroxyphenanthrenes. Characterization of hydroxyfluorene and 2-naphthol metabolites in urine may improve the characterization of PAHs from tobacco smoke and related disease risks among smokers and nonsmokers. PMID:22428611

St. Helen, Gideon; Goniewicz, Maciej L.; Dempsey, Delia; Wilson, Margaret; Jacob, Peyton; Benowitz, Neal L



Post 17th-century changes of European PAH emissions recorded in high-altitude Alpine snow and ice.  


The occurrence of organic pollutants in European Alpine snow/ice has been reconstructed over the past three centuries using a new online extraction method for polycyclic aromatic hydrocarbons (PAH) followed by liquid chromatographic determination. The meltwater flow from a continuous ice core melting system was split into two aliquots, with one aliquot directed to an inductively coupled plasma quadrupole mass spectrometer for continuous trace elements determinations and the second introduced into a solid phase C18 (SPE) cartridge for semicontinuous PAH extraction. The depth resolution for PAH extractions ranged from 40 to 70 cm, and corresponds to 0.7-5 years per sample. The concentrations of 11 PAH were determined in dated snow/ice samples to reconstruct the atmospheric concentration of these compounds in Europe for the last 300 years. The PAH pattern is dominated by phenanthrene (Phe), fluoranthene (Fla), and pyrene (Pyr), which represent 60-80% of the total PAH mass. Before 1875 the sum of PAH concentration (SigmaPAH) was very low with total mean concentrations less than 2 ng/kg and 0.08 ng/kg for the heavier compounds (SigmaPAH*, more than four aromatic rings). During the first phase of the industrial revolution (1770-1830) the PAH deposition showed a weak increase which became much greater from the start of the second phase of the industrial revolution at the end of 19th Century. In the 1920s, economic recession in Europe decreased PAH emissions until the 1930s when they increased again and reached a maximum concentration of 32 ng/kg from 1945 to 1955. From 1955 to 1975 the PAH concentrations decreased significantly, reflecting improvements in emission controls especially from major point sources, while from 1975 to 2003 they rose to levels equivalent to those in 1910. The Fla/(Fla+Pyr) ratio is often used for source assignment and here indicates an increase in the relative contribution of gasoline and diesel combustion with respect to coal and wood burning from 1860 to the 1980s. This trend was reversed during the last two decades. PMID:20392089

Gabrieli, Jacopo; Vallelonga, Paul; Cozzi, Giulio; Gabrielli, Paolo; Gambaro, Andrea; Sigl, Michael; Decet, Fabio; Schwikowski, Margit; Gäggeler, Heinz; Boutron, Claude; Cescon, Paolo; Barbante, Carlo




EPA Science Inventory

Soils with known history of exposure to polycyclic aromatic hydrocarbons (PAHS) were collected from Norway, Germany and the United States and screened for the presence of PAH-degrading bacteria. urified PAH-degrading isolates were characterized by fatty acid profile analysis (GC-...


Analysis of polyaromatic hydrocarbons (PAHs) using cyclodextrin and micellar chemistries  

SciTech Connect

Much of our recent work has focused on the interaction of polyaromatic hydrocarbons (PAHs) with cyclodextrins (CDxs). These interactions are in the form of guest/host complexes where the PAHs serve as guests and the CDxs serve as hosts. This talk will describe the recent developments in our laboratory of cyclodextrins for improved analysis of PAHs.

Warner, I.M.; Zung, J.B.; Blyshak, L. (Emory Univ., Atlanta, GA (USA))



Rapid persulfate oxidation predicts PAH bioavailability in soils and sediments  

Microsoft Academic Search

Persulfate oxidation was validated as a method to predict polycyclic aromatic hydrocarbon (PAH) bioavailability in soils and sediments. It was demonstrated for 14 field contaminated soils and sediments that residual PAH concentrations after a short (3 h) persulfate oxidation correspond well to residual PAH concentrations after 21 days of biodegradation. Persulfate oxidation of samples that had first been subjected to

Chiel Cuypers; Tim Grotenhuis; Jan Joziasse; Wim Rulkens



Assessment of PAH Levels in Atmospheric Particulates from  

E-print Network

. Toxic equivalent values were similar for both sets of samples (0.29-0.30 ng BaP TEQ/m 3 ). High molecular weight PAHs exhibited a tri-modal distribution at molecular weight PAHs were associated with the summer months, while higher molecular weight PAHs were



Microsoft Academic Search

The present work describes a coke oven soil treatability study by landfarming, conducted on-site in a field scale facility covering 100 m. The soil contamination was mainly due to high concentrations of polynuclear aromatic hydrocarbons (PAHs) up to 1140 mg\\/Kg dry weight (?EPA). Along the treatment process the soil was characterised at the chemical, microbiological and ecotoxicological levels. After 3

Ana Picado; Anabela Nogueira; Lina Baeta-Hall; Elsa Mendonça; Maria de Fátima Rodrigues; Maria do Céu Sàágua; Aida Martins; Ana Maria Anselmo



Sedimentary transport and fate of polycyclic aromatic hydrocarbons (PAH) from managed burning of moorland vegetation on a blanket peat, South Yorkshire, UK.  


This study reports the concentrations of 18 polycyclic aromatic hydrocarbons (PAH) from managed burning of moorland vegetation and compares them to PAH in catchment vegetation, underlying peats, head water suspended sediment (HSS), stream water and reservoir sediment cores. Total PAH ranged from 203 to 11,112 ?g/kg in the blanket peats, 101-290 ?g/kg in the fresh moorland vegetation, 4186 ?g/kg at the burnt site, 17,439 ?g/kg in the HSS, 56 ng/L in the stream water and 987 to 7346 ?g/kg in the reservoir sediments. No total or individual PAH concentrations exceeded the published sediment quality guidelines. The perylene content of selected moorland vegetation (sphagnum, heather and bilberry) ranged from 10 to 18% as compared to only 2% for the sediment hosted PAH. A comparison of whole and <250 ?m fractions from the burnt surface layer revealed a near threefold increase in PAH concentration in the fine fraction and a change in the PAH distribution such that naphthalene>phenanthrene>2-methylnaphthalene. Elevated total PAH contents were observed close to the blanket peat sediment surface (0-10 cm) and then declined at greater depths. The high PAH content of the HSS was attributed to the high sorption capacity of the organic-rich particles (TOC 25.8% (wt/wt)). The distribution of individual PAH in reservoir cores and HSS was consistent and the results of the principal component analysis and isomeric ratios suggest mainly pyrolytic inputs, from either vegetation burning and coal combustion. A comparison of the reservoir core PAH profiles shows that the source(s) have remained largely unchanged since the reservoir construction in 1929A.D. reflecting consistent moorland management practices. PMID:23416203

Vane, Christopher H; Rawlins, Barry G; Kim, Alexander W; Moss-Hayes, Vicky; Kendrick, Christopher P; Leng, Melanie J



Conserved themes in target recognition by the PAH1 and PAH2 domains of the Sin3 transcriptional corepressor.  


The recruitment of chromatin-modifying coregulator complexes by transcription factors to specific sites of the genome constitutes an important step in many eukaryotic transcriptional regulatory pathways. The histone deacetylase-associated Sin3 corepressor complex is recruited by a large and diverse array of transcription factors through direct interactions with the N-terminal PAH domains of Sin3. Here, we describe the solution structures of the mSin3A PAH1 domain in the apo form and when bound to SAP25, a component of the corepressor complex. Unlike the apo-mSin3A PAH2 domain, the apo-PAH1 domain is conformationally pure and is largely, but not completely, folded. Portions of the interacting segments of both mSin3A PAH1 and SAP25 undergo folding upon complex formation. SAP25 binds through an amphipathic helix to a predominantly hydrophobic cleft on the surface of PAH1. Remarkably, the orientation of the helix is reversed compared to that adopted by NRSF, a transcription factor unrelated to SAP25, upon binding to the mSin3B PAH1 domain. The reversal in helical orientations is correlated with a reversal in the underlying PAH1-interaction motifs, echoing a theme previously described for the mSin3A PAH2 domain. The definition of these so-called type I and type II PAH1-interaction motifs has allowed us to predict the precise location of these motifs within previously experimentally characterized PAH1 binders. Finally, we explore the specificity determinants of protein-protein interactions involving the PAH1 and PAH2 domains. These studies reveal that even conservative replacements of PAH2 residues with equivalent PAH1 residues are sufficient to alter the affinity and specificity of these protein-protein interactions dramatically. PMID:18089292

Sahu, Sarata C; Swanson, Kurt A; Kang, Richard S; Huang, Kai; Brubaker, Kurt; Ratcliff, Kathleen; Radhakrishnan, Ishwar



Rapid persulfate oxidation predicts PAH bioavailability in soils and sediments  

SciTech Connect

Persulfate oxidation was validated as a method to predict polycyclic aromatic hydrocarbon (PAH) bioavailability in soils and sediments. It was demonstrated for 14 field contaminated soils and sediments that residual PAH concentrations after a short (3 h) persulfate oxidation correspond well to residual PAH concentrations after 21 days of biodegradation. Persulfate oxidation of samples that had first been subjected to biodegradation yielded only limited additional PAH oxidation. This implies that oxidation and biodegradation removed approximately the same PAH fraction. Persulfate oxidation thus provides a good and rapid method for the prediction of PAH bioavailability. Thermogravimetric analysis of oxidized and untreated samples showed that persulfate oxidation primarily affected expanded organic matter. The results indicate that this expanded organic matter contained mainly readily bioavailable PAHs.

Cuypers, C.; Grotenhuis, T.; Joziasse, J.; Rulkens, W.



Diagnostic utility of CD4%:CD8 low% T-lymphocyte ratio to differentiate feline immunodeficiency virus (FIV)-infected from FIV-vaccinated cats.  


Antibody testing based on individual risk assessments is recommended to determine feline immunodeficiency virus (FIV) status, but ELISA and Western blot tests cannot distinguish between anti-FIV antibodies produced in response to natural infection and those produced in response to FIV vaccination. The aim of this cross-sectional study was to test the hypothesis that FIV-infected cats could be differentiated from FIV-vaccinated uninfected cats using lymphocyte subset results, specifically the CD4%:CD8(low)% T-lymphocyte ratio. Comparisons of the CD4%:CD8(low)% T-lymphocyte ratio were made among the following four groups: Group 1 - FIV-infected cats (n=61; FIV-antibody positive by ELISA and FIV PCR positive); Group 2 - FIV-uninfected cats (n=96; FIV-antibody negative by ELISA); Group 3 - FIV-vaccinated uninfected cats (n=31; FIV-antibody negative by ELISA before being vaccinated against FIV, after which they tested FIV ELISA positive); and Group 4 - FIV-uninfected but under chronic/active antigenic stimulation (n=16; FIV-antibody negative by ELISA; all had active clinical signs of either upper respiratory tract disease or gingival disease for ? 21 days). The median CD4%:CD8(low)% T-lymphocyte ratio was lower in Group 1 (1.39) than in each of the other three groups (Group 2 - 9.77, Group 3 - 9.72, Group 4 - 5.64; P<0.05). The CD4%:CD8(low)% T-lymphocyte ratio was also the most effective discriminator between FIV-infected cats and the other three groups, and areas under ROC curves ranged from 0.91 (compared with Group 4) to 0.96 (compared with Group 3). CD4%:CD8(low)% shows promise as an effective test to differentiate between FIV-infected cats and FIV-vaccinated uninfected cats. PMID:24559863

Litster, Annette; Lin, Jui-Ming; Nichols, Jamieson; Weng, Hsin-Yi



13CO2/12CO2 ratio analysis in exhaled air by lead-salt tunable diode lasers for noninvasive diagnostics in gastroenterology  

NASA Astrophysics Data System (ADS)

An analyzer of 13CO2/12CO2 ratio in exhaled air based on lead-salt tunable diode lasers is presented. High accuracy of the carbon isotope ratio detection in exhaled carbon dioxide was achieved with help of very simple optical schematics. It was based on the use of MBE laser diodes operating in pulse mode and on recording the resonance CO2 absorption at 4.2 micrometers . Special fast acquisition electronics and software were applied for spectral data collection and processing. Developed laser system was tested in a clinical train aimed to assessment eradication efficiency in therapy of gastritis associated with Helicobacter pylori infection. Data on the 13C-urea breath test used for P.pylori detection and obtained with tunable diode lasers in the course of the trail was compared with the results of Mass-Spectroscopy analysis and histology observations. The analyzer can be used also for 13CO2/12CO2 ratio detection in exhalation to perform gastroenterology breath test based on using other compounds labeled with stable isotopes.

Stepanov, Eugene V.; Zyrianov, Pavel V.; Miliaev, Valerii A.; Selivanov, Yurii G.; Chizhevskii, Eugene G.; Os'kina, Svetlana; Ivashkin, Vladimir T.; Nikitina, Elena I.




PubMed Central

The present study examines concentrations and risks of polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs (NPAHs), steranes, and hopanes in lake trout collected in Lake Michigan. A total of 74 fish were collected in 2 seasons at 3 offshore sites. The total PAH concentration (?9PAH) in whole fish ranged from 223 pg/g to 1704 pg/g wet weight, and PAH concentrations and profiles were similar across season, site, and sex. The total NPAH (?9NPAH) concentrations ranged from 0.2 pg/g to 31 pg/g wet weight, and carcinogenic compounds, including 1-nitropyrene and 6-nitrochrysene, were detected. In the fall, NPAH concentrations were low at the Illinois site (0.2–0.5 pg/g wet wt), and site profiles differed considerably; in the spring, concentrations and profiles were similar across sites, possibly reflecting changes in fish behavior. In the fall, the total sterane (?5Sterane) and total hopane (?2Hopane) levels reached 808 pg/g and 141 pg/g wet weight, respectively, but concentrations in the spring were 10 times lower. Concentrations in eggs (fall only) were on the same order of magnitude as those in whole fish. These results demonstrate the presence of target semivolatile organic compounds in a top predator fish, and are consistent with PAH biodilution observed previously. Using the available toxicity information for PAHs and NPAHs, the expected cancer risk from consumption of lake trout sampled are low. However, NPAHs contributed a significant portion of the toxic equivalencies in some samples. The present study provides the first measurements of NPAHs in freshwater fish, and results suggest that additional assessment is warranted. PMID:24764175

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



A novel approach to investigating indoor/outdoor pollution links: Combined magnetic and PAH measurements  

NASA Astrophysics Data System (ADS)

In a preliminary study, paired indoor and outdoor air sampling was conducted at three locations around the city of Lancaster, UK to examine the influence of combustion sources on air quality by measuring particulate concentrations, particulate magnetic properties and polyaromatic hydrocarbons (PAHs). With one exception (an indoor suburban air sample), outdoor air samples had higher total suspended particulates (TSP), particle-bound PAH concentrations and magnetic remanence (IRM) values. IRM values were highest for the week-day, outdoor city centre samples and then declined in the sequence: Sunday, city centre > suburban/residential > Lancaster University campus. These data indicate traffic as the major particle-bound PAH, particulates and magnetic source, particularly as sampling was conducted during July in the absence of any space heating. The indoor air samples revealed a wide variation in pollutant concentrations, characterised by higher vapour levels of 2-3 ring PAHs, variable TSP concentrations and variable but generally low IRMs. The differences in PAH concentrations, TSP and IRMs between outdoor and indoor environments indicate limited ingress of outdoor air pollutants to the indoor environment in this study. Our combined PAH and magnetic data identify specific and distinctive indoor pollution signals for each of our sampled sites, reflecting distinct sources. One site, the suburban house, has anomalously high IRM, TSP and particle-bound PAHs. A possible source for these is a cast-iron, wood-burning stove (even though not lit). The city centre indoor site is characterised by high TSP and very low IRMs but high values of the magnetic ratio of anhysteretic remanence:saturation remanence, indicative of ultrafine (sub-micrometre) magnetic grain sizes. The source for this city centre indoor signature is unidentified but may reflect the occupant smoking and/or lighting candles. The indoor campus sample was affected by loss-on-ignition procedures carried out in a teaching laboratory. The combined PAH and magnetic analyses thus provide a sensitive and discriminatory means of identifying outdoor, traffic-derived pollution, and of discriminating between different types of indoor pollution.

Halsall, C. J.; Maher, B. A.; Karloukovski, V. V.; Shah, P.; Watkins, S. J.


Polycyclic aromatic hydrocarbons (PAHs) in yogurt samples.  


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

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



[PAH Cations as Viable Carriers of DIBs  

NASA Technical Reports Server (NTRS)

This report is intended to fill in the blanks in NASA's file system for our lab astro study of molecular ions of astrophysical interest. In order to give NASA what it needs for its files, I attach below the text of the section from our recent proposal to continue this work, in which we describe progress to date, including a large number of publications. Our initial studies were focused on PAH cations, which appear to be viable candidates as the carriers of the DIBs, an idea that has been supported by laboratory spectroscopy of PAH cations in inert matrices. Beginning with the simplest aromatic (benzene; C6H6) and moving progressively to larger species (naphthalene, C10OH8; pyrene, C16H10; and most recently chrysene, C18H12), we have been able to derive rate coefficients for reactions with neutral spices that are abundant in the diffuse interstellar medium.

Snow, Ted



Carbon in The Universe: PAHs and Clusters  

NASA Technical Reports Server (NTRS)

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.

Saykally, Richard J.



Sorption and chemical transformation of PAHs on coal fly ash  

SciTech Connect

The objective of this research is to characterize the interactions of coal fly ash with polycyclic aromatic hydrocarbons (PAHs) and their derivatives, and to understand the influence of the surface properties of coal ash (and other atmospheric particles) on the chemical transformations of polycyclic aromatic compounds. Studies to be carried out in this project include: (1) Fractionation of heterogeneous coal fly ash samples into different particle types varying in size and chemical composition (carbonaceous, mineral-magnetic, and mineral nonmagnetic); (2) Measurement of the rates of chemical transformation of PAHs and PAH derivatives (especially nitro-PAHs) and the manner in which the rates of such processes are influenced by the chemical and physical properties of coal fly ash particles; (3) Chromatographic and spectroscopic studies of the nature of the interactions of coal fly ash particles with PAHs and PAH derivatives; (4) Characterization of the fractal nature of fly ash particles (via surface area measurements) and the relationships of surface roughness'' of fly ash particles to the chemical behavior of PAHs sorbed on coal ash particles; (5) Identification of the major products of chemical transformation of PAHs on coal ash particles, and examination of any effects that may exist of the nature of the coal ash surface on the identities of PAH transformation products; and (6) Studies of the influence of other sorbed species on the chemical behavior of PAHs and PAH derivatives on fly ash surfaces. PAHs are deposited, under controlled laboratory conditions, onto coal ash surfaces from the vapor phase, in order to mimic the processes by which PAHs are deposited onto particulate matter in the atmosphere.

Mamantov, G.; Wehry, E.L.



A Novel Approach to the Detection and Characterization of PAH Cations and PAH-Photoproducts  

NASA Astrophysics Data System (ADS)

Cationic polycyclic aromatic hydrocarbons (PAHs) are attractive candidates for the Diffuse Interstellar Bands, but to date not a single PAH species has been identified on the basis of a spectral agreement. This indicates either that the molecular diversity is very large or that the candidates that have been considered are not the correct ones. In particular, small/medium-sized PAH cations are submitted to photodissociation under UV photons from stars. Therefore it is of interest to characterize the spectroscopic properties of key breakdown products. Furthermore, these studies should be performed under conditions that mimic those found in interstellar space, which leads to additional experimental difficulties. We describe the approach we are developing with the PIRENEA set-up and present results on the 1-Methylpyrene cation and photo-derived species. Experimental measurements are guided by calculations based on density functional theory.

Kokkin, D. L.; Simon, A.; Marshall, C.; Bonnamy, A.; Joblin, C.



Efficacy of in-situ for the remediation of PAH contaminated soils  

Microsoft Academic Search

Polycyclic aromatic hydrocarbons (PAHs) are of environmental concern because many PAHs are either carcinogens or potential carcinogens. Petroleum products are a major source of PAHs. The occurrence of PAH contamination is widespread and novel treatment technologies for the remediation of contaminated soils are necessary.Ozone has been found to be extremely useful for the degradation of PAHs in soils. For these

Susan J. Masten; Simon H. R. Davies



Evaluation of an exposure assay to measure uptake of sediment PAH by fish.  


The ecological risks of polynuclear aromatic hydrocarbons (PAH) in aquatic sediments will vary with both toxicity and bioavailability to aquatic biota. While there are standardized protocols to test the acute toxicity of sediment-borne compounds to aquatic invertebrates, there are none for assessing bioavailability to fish. We found that sediment-borne PAH caused an exposure-dependent induction of cytochrome P450 (CYP1A) enzymes in rainbow trout (Oncorhynchus mykiss) fingerlings exposed in semi-static 96 h bioassays, as shown by increased activity of ethoxyresorufin-o-deethylase (EROD). Assuming that PAH are taken up by trout due to partitioning from organic and inorganic constituents of sediments, we tested the effect of different test variables on bioaccumulation using induction as an index of exposure. EROD activity increased with exposure of fish to increasing volumes of sediments containing PAH, i.e., with increasing ratios of sediment to water. Uptake of single compounds from sandy sediments did not differ from uptake from clay or low organic (7% LOI - loss on ignition) sediments, but decreased when organic content was very high (58% LOI). Maximum induction was observed within 24 h of exposure and at 7.5 degrees C relative to 15, 22, or 28 degrees C. Storage and handling techniques had minor effects on sediment EROD induction potency. Absolute EROD activity was greater in white sucker (Catostomus commersoni) a benthic species, than in trout, a pelagic species. However, when basal (negative control) activity was accounted for, there was no difference in response between the species. Together, these experiments provide a basis for developing a standard protocol to test the bioavailability to fish of sediment-borne PAH. PMID:16779608

Fragoso, Nuno M; Hodson, Peter V; Zambon, Silvia



Warm Dust and Spatially Variable PAH Emission in the Dwarf Starburst Galaxy NGC 1705  

E-print Network

We present Spitzer observations of the dwarf starburst galaxy NGC 1705 obtained as part of SINGS. The galaxy morphology is very different shortward and longward of ~5 microns: short-wavelength imaging shows an underlying red stellar population, with the central super star cluster (SSC) dominating the luminosity; longer-wavelength data reveals warm dust emission arising from two off-nuclear regions offset by ~250 pc from the SSC. These regions show little extinction at optical wavelengths. The galaxy has a relatively low global dust mass (~2E5 solar masses, implying a global dust-to-gas mass ratio ~2--4 times lower than the Milky Way average). The off-nuclear dust emission appears to be powered by photons from the same stellar population responsible for the excitation of the observed H Alpha emission; these photons are unassociated with the SSC (though a contribution from embedded sources to the IR luminosity of the off-nuclear regions cannot be ruled out). Low-resolution IRS spectroscopy shows moderate-strength PAH emission in the 11.3 micron band in the eastern peak; no PAH emission is detected in the SSC or the western dust emission complex. There is significant diffuse 8 micron emission after scaling and subtracting shorter wavelength data; the spatially variable PAH emission strengths revealed by the IRS data suggest caution in the interpretation of diffuse 8 micron emission as arising from PAH carriers alone. The metallicity of NGC 1705 falls at the transition level of 35% solar found by Engelbracht and collaborators; the fact that a system at this metallicity shows spatially variable PAH emission demonstrates the complexity of interpreting diffuse 8 micron emission. A radio continuum non-detection, NGC 1705 deviates significantly from the canonical far-IR vs. radio correlation. (Abridged)

John M. Cannon; John-David T. Smith; Fabian Walter; George J. Bendo; Daniela Calzetti; Daniel A. Dale; Bruce T. Draine; Charles W. Engelbracht; Karl D. Gordon; George Helou; Robert C. Kennicutt, Jr.; Claus Leitherer; Lee Armus; Brent A. Buckalew; David J. Hollenbach; Thomas H. Jarrett; Aigen Li; Martin J. Meyer; Eric J. Murphy; Michael W. Regan; George H. Rieke; Marcia J. Rieke; Helene Roussel; Kartik Sheth; Michele D. Thornley



[SiPAH]+ pi-Complexes in the Interstellar Medium  

E-print Network

We investigate the presence of silicon atoms adsorbed on the surface of interstellar polycyclic aromatic hydrocarbons (PAHs) to form SiPAH pi-complexes. We use quantum chemistry calculations to obtain structural, thermodynamic and mid-IR properties of neutral and cationic SiPAH complexes. The binding energy was found to be at least 1.5 eV for [SiPAH]+ complexes whereas it is roughly 0.5 eV for their neutral counterparts. From the spectral analysis of the calculated IR spectra, we found that the coordination of silicon to PAH+ does not strongly affect the intensities of the PAH+ spectra, but systematically introduces blueshifts of the C-C in-plane and the C-H out-of-plane bands. The thermodynamic data calculated for [SiPAH]+ complexes show that these species are stable and can be easily formed by radiative association of Si+ and PAH species that are known to be abundant in photodissociation regions. Their mid-IR fingerprints show features induced by the coordination of silicon that could account for (i) the blueshifted position of the 6.2 micron AIB and (ii) the presence of satellite bands observed on the blue side of the 6.2 and 11.2 micron AIBs. From such an assignment, we can deduce that typically 1% of the cosmic silicon appears to be attached to PAHs.

B. Joalland; A. Simon; C. J. Marsden; C. Joblin



PAH metabolites in European eels (Anguilla anguilla) as indicators of PAH exposure: different methodological approaches.  


Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants of aquatic environments derived from pyrogenic and petrogenic sources. In fish, as in other vertebrates, PAHs are rapidly metabolized. However, the metabolites have been proven to induce multiple deleterious effects in fish. The concentrations of biliary polycyclic aromatic hydrocarbon metabolites in eels (Anguilla anguilla) caught in Polish waters were measured. The main objectives of the study were to provide information on the levels of PAH metabolites in eels inhabiting Polish waters and to discuss which methodological approach is appropriate for assessing PAH exposure in aquatic ecosystems. The non-normalized median concentration of 1-OH Pyr and 1-OH Phe measured in eels from Polish waters ranged from 11 to 1642 ng ml(-1) bile and from 83 to 929 ng ml(-1) bile, respectively, depending on the sampling site. Data normalization in relation to bile pigment content reduced inter-site variation, and the normalized median concentrations of 1-OH Pyr and 1-OH Phe ranged from 0.44 to 20.24 ng A(-1)380 and from 1.58 to 11.11 ng A(-1)380, respectively. Our study indicated that results were more consistent for the two species sampled in the same area (eel examined in the current study and flounder examined in our previous study) when the fluorescence response of diluted bile samples was compared than when concentrations of 1-OH Pyr determined with the mean of HPLC were compared. PMID:25064716

Szlinder-Richert, J; Nermer, T; Szatkowska, U




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...


Determination of urinary metabolites of polycyclic aromatic hydrocarbons (PAH) for the risk assessment of PAH-exposed workers  

Microsoft Academic Search

A method for the simultaneous determination of urinary phenanthrene, fluoranthene, pyrene, chrysene and benzo[a]pyrene metabolites has been developed for individual risk assessment at polycyclic aromatic hydrocarbon (PAH)-burdened workplaces.\\u000a The concentration of urinary metabolites as a measure for individual PAH exposure takes account not only of PAH masses resorbed\\u000a by the respiratory tract but also those incorporated percutaneously. The method allows

G. Grimmer; J. Jacob; G. Dettbarn; K.-W. Naujack



Chemical characteristic and toxicity assessment of particle associated PAHs for the short-term anthropogenic activity event: During the Chinese New Year's Festival in 2013.  


PM10 and PM2.5 samples were simultaneously collected during a period which covered the Chinese New Year's (CNY) Festival. The concentrations of particulate matter (PM) and 16 polycyclic aromatic hydrocarbons (PAHs) were measured. The possible source contributions and toxicity risks were estimated for Festival and non-Festival periods. According to the diagnostic ratios and Multilinear Engine 2 (ME2), three sources were identified and their contributions were calculated: vehicle emission (48.97% for PM10, 53.56% for PM2.5), biomass & coal combustion (36.83% for PM10, 28.76% for PM2.5), and cook emission (22.29% for PM10, 27.23% for PM2.5). An interesting result was found: although the PAHs are not directly from the fireworks display, they were still indirectly influenced by biomass combustion which is affiliated with the fireworks display. Additionally, toxicity risks of different sources were estimated by Multilinear Engine 2-BaP equivalent (ME2-BaPE): vehicle emission (54.01% for PM10, 55.42% for PM2.5), cook emission (25.59% for PM10, 29.05% for PM2.5), and biomass & coal combustion source (20.90% for PM10, 14.28% for PM2.5). It is worth to be noticed that the toxicity contribution of cook emission was considerable in Festival period. The findings can provide useful information to protect the urban human health, as well as develop the effective air control strategies in special short-term anthropogenic activity event. PMID:24632060

Shi, Guo-Liang; Liu, Gui-Rong; Tian, Ying-Ze; Zhou, Xiao-Yu; Peng, Xing; Feng, Yin-Chang



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

PubMed Central

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 ?PAHs (10 compounds), ?NPAHs (6 compounds), ?hopanes (2 compounds), and ?steranes (2 compounds) were 2.52, 0.351, 0.02 ~ 2 and 1?g/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

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



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


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 ?PAHs (10 compounds), ?NPAHs (6 compounds), ?hopanes (2 compounds), and ?steranes (2 compounds) were 2.52, 0.351, 0.02 ~ 2 and 1?g/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

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



Infrared Emission from Interstellar Dust. IV. The Silicate-Graphite-PAH Model in the Post-Spitzer Era  

E-print Network

Infrared (IR) emission spectra are calculated for dust composed of mixtures of amorphous silicate and graphitic grains, including varying amounts of polycyclic aromatic hydrocarbon (PAH) particles. The models are constrained to reproduce the average Milky Way extinction curve. The calculations include the effects of single-photon heating. Updated IR absorption properties for the PAHs are presented, that are consistent with observed emission spectra, including those newly obtained by Spitzer Space Telescope. We find a size distribution for the PAHs that results in emission band ratios consistent with observed spectra of the Milky Way and other galaxies. Emission spectra are presented for various intensities of the illuminating starlight. We calculate how the efficiency of emission into different IR bands depends on PAH size; the strong 7.7um emission feature is produced mainly by PAH particles containing Umin. We present graphical procedures using IRAC and MIPS photometry to estimate qpah, Umin, and gamma, the fraction f_PDR of the dust luminosity coming from photodissociation regions with U>100, and the total dust mass Mdust.

B. T. Draine; Aigen Li



PAH refractory index as a source discriminant of hydrocarbon input from crude oil and coal in Prince William Sound, Alaska  

USGS Publications Warehouse

Geochemical correlation and differentiation of hydrocarbons from crude oils and coals is difficult. The complex mixture of the hydrocarbon constituents and the dynamic nature of these constituents in the environment as they weather contribute to this difficulty A new parameter, the polycyclic aromatic hydrocarbon (PAH) refractory index, is defined here to help in this correlation. The PAH refractory index is a ratio of two of the most refractory constituents of most crude oils, namely triaromatic steranes and monomethylchrysenes. These are among the most persistent compounds in oil after deposition in the environment and thus retain reliably the signature of the original petroleum input. This index is utilized in Prince William Sound (PWS) to differentiate three different oils, as well as to provide evidence that coal, not oil, is the dominant source of the PAHs which are prominent constituents of marine sediments from PWS and the Gulf of Alaska.Geochemical correlation and differentiation of hydrocarbons from crude oils and coals is difficult. The complex mixture of the hydrocarbon constituents and the dynamic nature of these constituents in the environment as they weather contribute to this difficulty. A new parameter, the polycyclic aromatic hydrocarbon (PAH) refractory index, is defined here to help in this correlation. The PAH refractory index is a ratio of two of the most refractory constituents of most crude oils, namely triaromatic steranes and monomethylchrysenes. These are among the most persistent compounds in oil after deposition in the environment and thus retain reliably the signature of the original petroleum input. This index is utilized in Prince William Sound (PWS) to differentiate three different oils, as well as to provide evidence that coal, not oil, is the dominant source of the PAHs which are prominent constituents of marine sediments from PWS and the Gulf of Alaska.

Hostettler, F.D.; Rosenbauer, R.J.; Kvenvolden, K.A.




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...


Lipid-content-normalized polycyclic aromatic hydrocarbons (PAHs) in the xylem of conifers can indicate historical changes in regional airborne PAHs.  


The temporal variation of polycyclic aromatic hydrocarbons (PAHs) concentrations as well as the lipid content in the xylem of Masson pine trees sampled from the same site were determined and compared with the days of haze occurrence and with the historical PAHs reported in sedimentary cores. The patterns of the lipid content as well as the PAH concentrations based on the xylem dry weight (PAHs-DW) decreased from the heartwood to the sapwood. The trajectories of PAHs normalized by xylem lipid content (PAHs-LC) coincided well with the number of haze-occurred days and were partly similar with the historical changes in airborne PAHs recorded in the sedimentary cores. The results indicated that PAHs-LC in the xylem of conifers might reliably reflect the historical changes in airborne PAHs at a regional scale. The species-specificity should be addressed in the utility and application of dendrochemical monitoring on historical and comparative studies of airborne PAHs. PMID:25299794

Kuang, Yuan-Wen; Li, Jiong; Hou, En-Qing



PAHs in Stockholm window films: Evaluation of the utility of window film content as indicator of PAHs in urban air  

NASA Astrophysics Data System (ADS)

The thin organic film that builds up on the exterior surface of windows has been proposed as a ubiquitously available passive sampler for semi-volatile organic contaminants (SOCs) in urban air. Readily available school windows were sampled in Stockholm city centre and suburban locations in both winter and summer season to evaluate the putative usefulness of this matrix for assessing the integrated load of urban air pollution by polycyclic aromatic hydrocarbons (PAHs). The window-area normalised concentrations indicated more PAH contamination in the winter than in the summer in both the city centre and suburban locations, with highest concentrations in the city centre in the winter (?PAH 43 451-467 ng m -2). However, normalising the PAH load to the amount of fatty window film, as measured by extractable organic matter (EOM), gave a more homogeneous picture with the EOM-normalised PAH load being inseparable both between summer and winter and between city centre and suburban locations. To evaluate the possibility of quantitatively employing urban window films as a means to provide predicted environmental concentrations of PAHs in air (PEC air), window film-air partition coefficients of PAHs were estimated using a set of coupled linear free energy relationships and physico-chemical properties of PAHs. Assuming dynamic equilibria between PAHs in air and dissolved in the window film, the obtained PEC air from the window films were consistently overestimating the urban vapour-phase PAH concentrations by factors 4-135. This discrepancy is quantitatively consistent with a strong and overwhelming association with black carbon aerosol particles accumulated in the window film. For SOCs that have a lower tendency to associate with black carbon, bulk window film concentrations may work better than for PAHs to estimate their vapour-phase concentrations in urban air.

Unger, Maria; Gustafsson, Örjan


Organic mulch biowall for PAH contaminated groundwater remediation  

Microsoft Academic Search

Organic mulch was used as an alternative supporting material in permeable, biological, barrier walls to prevent migration of PAHs. Three types of organic mulch, cypress bark (C), hardwood bark (H) and pine bark nuggets (P) were selected as potential media to capture pollutants or to support PAH-degrading microorganisms. Among the media, the hardwood mulch was selected for biowall testing. To

Youngwoo Seo; Am Jang; Paul L. Bishop



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

SciTech Connect

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 energy 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.

Viamajala, S.; Peyton, B. M.; Richards, L. A.; Petersen, J. N.




EPA Science Inventory

The Replicates/PAH database contains the analytical results of PAH concentrations in replicate samples. The samples were analyzed as part of the QA/QC protocols of the NHEXAS project. The class of analytes consist of 24 seperate compounds including the BAP series. The NHEXAS p...


Profile variations of the 3 to 12 micron PAH features  

Microsoft Academic Search

We present 3--12 micron ISO-SWS spectra of a sample of reflection nebulae, HII regions, YSOs, evolved stars and galaxies that show strong unidentified infrared bands, commonly attributed to Polycyclic Aromatic Hydrocarbons (PAHs). The main PAH emission features in this wavelength region show large variations in profile and peak position. Furthermore, the observed pronounced contrast in the spectral variations for the

E. Peeters; B. van Diedenhoven; C. van Kerckhoven; S. Hony; A. G. G. M. Tielens; L. J. Allamandola; D. M. Hudgins; C. W. Bauschlicher



Imaging of the PAH Emission Bands in the Orion Bar  

NASA Technical Reports Server (NTRS)

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.

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



Polycyclic aromatic hydrocarbons (PAHs) in indoor emission from decorative candles  

NASA Astrophysics Data System (ADS)

This study investigates PAHs indoor emissions from burning decorative candle in an indoor environment because emissions from burning wax in home have rarely been addressed. A total of 12 air samples were collected during the entire burning period of the decorative candles. Particulate and gaseous PAHs emissions were simultaneously measured by passing effluent through a filter (to collect particulate-phase PAHs), a cold trap and ORBO 43 tubes (to capture gaseous-phase PAHs). Analysis involved ultrasound extraction, followed by gas chromatography-mass spectrometry (GC-MS). The measured total PAHs concentration (particulate + aqueous phase + gas phases) for the candles, reported as mass of PAHs emitted/mass of candle burning, was between 2.3 and 49.8 ?g kg -1 and mean 15 ?g kg -1. Considering the volume of sampled air, the concentrations of total PAHs ranged from 7 ng m -3 to 267 ng m -3. Concentrations of B[ a]P emitted by candles ranged from 0.1 to 7.5 ng m -3, while total carcinogenic PAHs, expressed as B[a] eq, ranged from 0.2 to 10.7 ng m -3. The values of all the isomeric indices calculated in this research are in good agreement to literature data for emissions from high temperature processes.

Orecchio, Santino



Comparative Developmental Toxicity of Environmentally Relevant Oxygenated PAHs  

SciTech Connect

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-utero 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.

Knecht, Andrea; Goodale, Britton; Truong, Lisa; Simonich, Michael; Swanson, Annika; Matzke, Melissa M.; Anderson, Kim A.; Waters, Katrina M.; Tanguay, Robert



Laboratory Spectroscopy of Protonated PAH Molecules Relevant For Interstellar Chemistry  

NASA Astrophysics Data System (ADS)

In this contribution, we summarize the recent progress made in recording laboratory infrared (IR) spectra of protonated polycyclic aromatic hydrocarbon molecules (H+PAH) in the gas phase. The IR spectra of a large variety of H+PAH species ranging from benzene to coronene have been obtained by various variants of photodissociation spectroscopy. The employed techniques include single-photon IR photodissociation (IRPD) of tagged H+PAH ions and IR multiple-photon dissociation (IRMPD) of bare H+PAH ions. The comparison of the laboratory IR spectra with astronomical spectra supports the hypothesis that H+PAH ions are possible carriers of the unidentified IR emission (UIR) bands. Moreover, the spectra provide detailed information about the geometric and electronic structure as well as the chemical reactivity and stability of these fundamental hydrocarbon ions.

Dopfer, O.



On the Viability of the PAH Model as an Explanation of the Unidentified Infrared Emission Features  

NASA Astrophysics Data System (ADS)

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 for the PAH hypothesis.

Zhang, Yong; Kwok, Sun



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

NASA Astrophysics Data System (ADS)

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

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



Polycyclic Aromatic Hydrocarbon (PAH) and Oxygenated PAH (OPAH) Air-Water Exchange during the Deepwater Horizon Oil Spill.  


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 flux of both PAHs and OPAHs during the DWH. Vapor phase sum PAH and OPAH concentrations ranged between 1 and 24 ng/m(3) and 0.3 and 27 ng/m(3), respectively. PAH and OPAH concentrations in air exhibited different spatial and temporal trends than in water, and air-water flux of 13 individual PAHs were strongly associated with the DWH incident. The largest PAH volatilizations occurred at the sites in Alabama and Mississippi in the summer, each nominally 10?000 ng/m(2)/day. Acenaphthene was the PAH with the highest observed volatilization rate of 6800 ng/m(2)/day in September 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:25412353

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



Modelling the physical and chemical evolution of PAHs and PAH-related species in astrophysical environments  

NASA Astrophysics Data System (ADS)

An active carbon chemistry is observed at the border of photo-dissociation regions (PDRs), involving small hydrocarbons, polycyclic aromatic hydrocarbon (PAH) macromolecules and evaporating very small grains (VSGs). In this context, we aim at quantifying the physical and chemical evolution of PAHs (hydrogenation and charge states, aggregation, and complexation with heavy atoms) as a function of the local physical conditions (radiation field, temperature, density, abundances of atomic and molecular hydrogen, electrons and heavy atoms). We have developed a numerical model that follows the time dependency of the abundance and internal energy of each species. In this paper, we use this model to calculate the hydrogenation and charge states of coronene C24H12 as an interstellar PAH prototype. We take advantage of recent results on photodissociation and reaction rates and provide guidelines for future laboratory studies. Reaction rates of coronene-derived radical cations with H and H2 are found to be sufficiently constrained by experiments, whereas the absence of experimental data for neutral species is critical.

Montillaud, J.; Joblin, C.; Toublanc, D.



Infrared absorption and emission characteristics of interstellar PAHs  

NASA Technical Reports Server (NTRS)

The mid-infrared interstellar emission spectrum with features at 3.28, 6.2, 7.7, 8.7 and 11.3 microns is discussed in terms of the Polycyclic Aromatic Hydrocarbon (PAH) hypothesis, which is based on the suggestive, but inconclusive comparison between the interstellar emission spectrum with the infrared absorption and Raman spectra of a few PAHs. The fundamental vibrations of PAHs and PAH-like species which determine the IR and Raman properties are discussed. Interstellar IR band emission is due to relaxation from highly vibrationally excited PAHs excited by ultraviolet photons. The excitation/emission process is described and the IR fluorescence from one PAH, chrysene, is traced. Generally, there is sufficient energy to populate several vibrational levels in each mode. Molecular vibrational potentials are anharmonic and emission from these higher levels will fall at lower frequencies and produce weak features to the red of the stronger fundamentals. This process is also described and can account for some spectroscopic details of the interstellar emission spectra previously unexplained. Analysis of the interstellar spectrum shows that PAHs contain between 20 and 30 carbon atoms are responsible for the emission.

Barker, J. R.; Allamandola, Louis J.; Tielens, Alexander G. G. M.; Barker, J. R.; Barker, J. R.



Dust Masses, PAH Abundances, and Starlight Intensities in the SINGS Galaxy Sample  

E-print Network

Physical dust models are presented for 65 galaxies in the SINGS survey that are strongly detected in the four IRAC bands and three MIPS bands. For each galaxy we estimate (1) the total dust mass, (2) the fraction of the dust mass contributed by PAHs, and (3) the intensity of the starlight heating the dust grains. We find that spiral galaxies have dust properties resembling the dust in the local region of the Milky Way, with similar dust-to-gas ratio, and similar PAH abundance. The observed SEDs, including galaxies with SCUBA photometry, can be reproduced by dust models that do not require "cold" (T8.1, grains contain a substantial fraction of interstellar Mg, Si and Fe. Galaxies with A_O8.1 have a median q_PAH=3.55%. The derived dust masses favor a value X_CO approx 4e20 cm^{-2}(K kms)^{-1} for the CO to H_2 conversion factor. Except for some starbursting systems (Mrk33, Tolo89, NGC3049), dust in the diffuse ISM dominates the IR power.

B. T. Draine; D. A. Dale; G. Bendo; K. D. Gordon; J. D. T. Smith; L. Armus; C. W. Engelbracht; G. Helou; R. C. Kennicutt; A. Li; H. Roussel; F. Walter; D. Calzetti; J. Moustakas; E. J. Murphy; G. H. Rieke; C. Bot; D. J. Hollenbach; K. Sheth; H. I. Teplitz



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

NASA Astrophysics Data System (ADS)

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 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.

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



Integrated diagnostics  

NASA Technical Reports Server (NTRS)

Recently completed projects in which advanced diagnostic concepts were explored and/or demonstrated are summarized. The projects begin with the design of integrated diagnostics for the Army's new gas turbine engines, and advance to the application of integrated diagnostics to other aircraft subsystems. Finally, a recent project is discussed which ties together subsystem fault monitoring and diagnostics with a more complete picture of flight domain knowledge.

Hunthausen, Roger J.



Laboratory Investigations of the Formation of Superhydrogenated PAHs  

NASA Astrophysics Data System (ADS)

We present experimental investigations of the formation of superhydrogenated polycyclic aromatic hydrocarbons (PAHs) through exposure of neutral PAHs to atomic hydrogen. Post irradiation thermal desorption measurements demonstrate that it is possible to form superhydrogenated coronene molecules with surprisingly high numbers of additional H atoms. We observe species with in excess of 20 additional H atoms, approaching the fully hydrogenated limit, perhydrocoronene. Scanning tunneling microscopy (STM) measurements provide insight into the changes to the electronic structure of the coronene species as a result of the hydrogenation process. Submolecular structure observed in the STM images indicates that a range of different sites on the coronene molecule are hydrogenated. The formation of PAHs with such high degrees of superhydrogenation may have important implications for molecular hydrogen formation in the ISM. Recent density functional theory calculations1 have indicated the efficient formation of H2 through a combination of hydrogenation and abstraction reactions involving neutral PAHs and their superhydrogenated forms. Although previous measurements by Menella2 have demonstrated the efficiency of both H addition and subsequent abstraction reactions involving a complex aromatic carbon grain mimic, the measurements reported here provide the first direct observation of neutral PAH superhydrogenation by H atom addition. The role played by PAHs in H2 formation is suggested by observations of a correlation between H2 and PAHs abundances in photodissociation regions3. Routes to H2 involving PAH cations have been investigated by several groups4-6 and the role played by anions has also been considered7. The present work demonstrates that neutral PAHs may also provide a formation route for this most important of interstellar molecules.

Thrower, J.; Friis, E.; Jorgensen, B.; Nilsson, L.; Baouche, S.; Balog, R.; Cassidy, A.; Hornekae, L.



Modeling the PAH Emission Spectra of Protoplanetary and Debris Disks  

NASA Astrophysics Data System (ADS)

The 3.3, 6.2, 7.7, 8.6 and 11.3 micron emission features of polycyclic aromatic hydrocarbon (PAH) molecules have been detected in protoplanetary disks around Herbig Ae/Be stars and T Tauri stars and in debris disks around main-sequence stars. PAHs play an important role in the thermal budget and chemistry of the gas in the disk, by providing photoelectrons for heating the gas and large surface areas for chemical reactions. Stochastically heated by a single UV/visible photon, the PAH emission is spatially more extended than large grains and therefore, the disks can be more easily resolved at the PAH emission bands. We propose to model the PAH emission spectra of protoplanetary and debris disks obtained by Spitzer and ISO. We will first calculate the temperature probability distribution functions dP/dT for both neutral and ionized PAHs of a wide range of sizes, at a wide range of radial distances (from the central star) in disks illuminated by stars of a wide range of spectral types. By modeling the PAH emission of dust disks, we will be able (1) to derive the abundance, size and spatial distributions of PAHs; (2) to derive the PAH photoelectric heating rates which dominate the gas heating in the disk surface layers; and (3) to see how the abundance and properties of the PAHs vary among disks at different evolutionary stages and illuminated by stars of different parameters (e.g. luminosity, spectral type). This program will create a web-based ``library'' of the temperature distribution functions dP/dT of PAHs (and their emission spectra and photoelectric heating rates) as a function of size, charge state, and radial distance in disks illuminated by stars of different spectral types. This library, a useful tool for interpreting the PAH emission features of dust disks obtained by Spitzer and for understanding the disk chemistry, will be made publicly available by April 2007 via the WWW at

Li, Aigen; Lunine, J. I.



Maturation of Rb+ and PAH accumulation by rabbit anterior uvea and choroid plexus  

SciTech Connect

In vitro accumulation of radioactive para-aminohippuric acid (/sup 3/H-PAH) and rubidium (/sup 86/Rb+) by the anterior uvea, ciliary processes, and the choroid plexus was evaluated in tissues from newborn and various aged rabbits. Accumulation of PAH was present in the anterior uvea at 1 day of age (tissue to media ratio, T/M, of 2.1 +/- 0.2) and remained at this level for the first 14 days of life. Accumulation did not rise to adult levels until 21 days of age (T/M 5.5 +/- 0.6). Rubidium accumulation in the anterior uvea, a measure of Na+, K+-pump activity, was higher than adult values 6 hr after birth (T/M25.2 +/- 0.9). Activity remained elevated through day 28 and did not fall to adult levels until day 60 (T/M 13.4 +/- 0.6). Accumulation studies on isolated ciliary processes were similar to those obtained from anterior uveal tissue. Daily subcutaneous injections of penicillin (300,000 units/kg/day) for 1 week had no effect on anterior uvea PAH accumulation (penicillin T/M was 1.7 +/- 0.1 and saline control T/M was 2.0 +/- 0.2). Accumulation of either /sup 3/H-PAH or /sup 86/Rb+ by the choroid plexus was present 1 day after birth in amounts that were similar to adult values and did not change during the 90 days of testing.

Krupin, T.; Fritz, C.; Becker, B.



PAH fluxes to Siskiwit revisted: trends in fluxes and sources of pyrogenic PAH and perylene constrained via radiocarbon analysis.  


Trends in concentrations and radiocarbon content of pyrogenic PAHs and perylene were determined 20 years after a previous study by Mcveety and Hites (1988). Pyrogenic PAH fluxes to sediments were observed to continue to decrease over the period from 1980 to 2000 at this remote site in contrast to observations in more urban areas. Radiocarbon analysis of pyrogenic PAHs showed a 50% decrease in the proportion of pyrogenic PAH derived from fossil fuel combustion over the past 50 years, consistent with decreasing emissions from regional coal-fired power-generating plants. Fluxes of pyrogenic PAHs related to biomass burning were consistent over this same period and found to exceed fossil fuel sources in the most recent samples. Fluxes of biomass-derived pyrogenic PAHs were similar in magnitude to total pyrogenic PAH fluxes in early 1900, suggesting that these fluxes may represent wildfire inputs. Not only did perylene concentrations in these sediments increase with depth as previously observed but also concentrations from the same sedimentary layers analyzed 20 years previously showed large increases in perylene concentrations. Radiocarbon analysis of perylene indicated that 70-85% of perylene observed in the deeper sediments could be explained by production from total organic carbon. PMID:23582045

Slater, G F; Benson, A A; Marvin, C; Muir, D




SciTech Connect

We use mid-infrared (MIR) spectroscopy from the Spitzer Infrared Spectrograph to study the nature of star-formation and supermassive black hole accretion for a sample of 65 IR-luminous galaxies at 0.02 < z < 0.6 with F(24 {mu}m) > 1.2 mJy. The MIR spectra cover wavelengths 5-38 {mu}m, spanning the polycyclic aromatic hydrocarbon (PAH) features and important atomic diagnostic lines. Our sample of galaxies corresponds to a range of total IR luminosity, L{sub IR} = L(8-1000 {mu}m) = 10{sup 10}-10{sup 12} L{sub Sun} (median L{sub IR} of 3.0 Multiplication-Sign 10{sup 11} L{sub Sun }). We divide our sample into a subsample of galaxies with Spitzer Infrared Array Camera 3.6-8.0 {mu}m colors indicative of warm dust heated by an active galactic nucleus (AGN; IRAGN) and those galaxies whose colors indicate star-formation processes (non-IRAGN). Compared to the non-IRAGN, the IRAGN show smaller PAH emission equivalent widths, which we attribute to an increase in mid-IR continuum from the AGN. We find that in both the IRAGN and star-forming samples, the luminosity in the PAH features correlates strongly with [Ne II] {lambda}12.8 {mu}m emission line, from which we conclude that the PAH luminosity directly traces the instantaneous star-formation rate (SFR) in both the IRAGN and star-forming galaxies. We compare the ratio of PAH luminosity to the total IR luminosity, and we show that for most IRAGN star-formation accounts for 10%-50% of the total IR luminosity. We also find no measurable difference between the PAH luminosity ratios of L{sub 11.3}/L{sub 7.7} and L{sub 6.2}/L{sub 7.7} for the IRAGN and non-IRAGN, suggesting that AGN do not significantly excite or destroy PAH molecules on galaxy-wide scales. Interestingly, a small subset of galaxies (8 of 65 galaxies) show a strong excess of [O IV] {lambda}25.9 {mu}m emission compared to their PAH emission, which indicates the presence of heavily-obscured AGN, including 3 galaxies that are not otherwise selected as IRAGN. The low PAH emission and low [Ne II] emission of the IRAGN and [O IV]-excess objects imply the IR luminosity of these objects is dominated by processes associated with the AGN. Because these galaxies lie in the ''green valley'' of the optical color-magnitude relation and have low implied SFRs, we argue their hosts have declining SFRs and these objects will transition to the red sequence unless some process restarts their star-formation.

Shipley, Heath V.; Papovich, Casey [George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, and Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843-4242 (United States); Rieke, George H.; Jannuzi, Buell T.; Weiner, Benjamin [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85719 (United States); Dey, Arjun [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ, 85719 (United States); Moustakas, John, E-mail: [Department of Physics and Astronomy, Siena College, Loudonville, NY 12211 (United States)



Effect of the site of infusion of para-aminohippuric acid (PAH) on portal blood flow  

E-print Network

Effect of the site of infusion of para-aminohippuric acid (PAH) on portal blood flow LM Zeoula C-308) suggested that mixing of PAH in portal blood could be improved by infusing PAH simultaneously via a ruminal of the PAH infusion site in different animals such that the infusion site effect may have been biased

Paris-Sud XI, Université de


Deuterium Enrichment of PAHs by VUV Irradiation of Interstellar Ices  

NASA Technical Reports Server (NTRS)

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.

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



Effects of PAHs on the feeding activity of tubificid worms  

SciTech Connect

Sediment collected from a clean site in LA was sieved through a 125{mu}m screen and contaminated with individual PAHs (pyrene, phenanthrene and dibenzofuran) at increasing concentrations using spiking procedure and with a mixture of the 3 PAHs at a single concentration by shell coating. Feeding activity was estimated by defecation rate. Groups of 15 worms were assigned to defecation chambers in 4 replicates per treatment. Feces were collected daily for 10 days, filtered through a 8{mu}m membrane filter and dry weight measured. Results obtained with phenanthrene and mixture of 3 PAHs indicate that PHA bulk concentration of 100 mg/dry kg and higher significantly reduce tubificid ingestion of sediment. Total recovery to control levels occurred when worms exposed to high concentration of PAH were transferred to clean sediment. Total OC was determined to be 3.2 %.

Lotufo, G.R. [Louisiana State Univ., Baton Rouge, LA (United States)



Biodegradability of select polycyclic aromatic hydrocarbon (pah) mixtures  

E-print Network

observed in binary and ternary mixtures require a multisubstrate model to account for simultaneous degradation of substrates. However, developing models that account for sequential degradation may be useful in scenarios where PAHs may not be competitive...

Desai, Anuradha M.



Gas/particle partitioning of n-alkanes, PAHs and oxygenated PAHs in urban Denver  

NASA Astrophysics Data System (ADS)

In this study, a medium volume sampler equipped with quartz fiber filters (QFFs) and a polyurethane foam (PUF)/XAD-4/PUF sandwich (PXP) was used to collect semi-volatile organic compounds (SVOCs) in both gaseous and particle (PM2.5) phases. A backup QFF (bQFF) was used to evaluate possible sampling artifact of particulate organics due to vapor-phase adsorption. A series of n-alkanes (molecular weight: 170-562) and PAHs (128-300), and two oxy-PAHs (acenaphthenone, 168; fluorenone, 180) were measured. Breakthrough experiments demonstrated that the PXP could collect all gas-phase target compounds with high efficiency, even the low molecular weight (MW) species (e.g., naphthalene). Comparing species concentrations across different sampling matrices encountered at the Denver, Colorado field site, the light n-alkanes (MW < 282) and PAHs (MW < 192) were mostly distributed into the gas phase; while those heavy n-alkanes (MW > 324) and PAHs (MW > 202) were primarily in the particle phase (Average temperature, 12.5 ± 10.1 °C). Log values of measured gas/particle (G/P) partitioning coefficients (Kmp,OM) of selected SVOCs (docosane, tricosane, fluoranthene, pyrene, acenaphthenone and fluorenone) were linearly regressed to those of theoretically-based partitioning coefficients (Ktp,OM) for comparison. Prior to Kmp,OM calculation, the gas- and particle-phase concentrations of SVOCs were corrected following two different approaches based on bQFF measurements. The first approach assumed that the bQFF associated SVOCs were from the adsorption of gaseous SVOCs (positive artifact); the second approach assumed equal contributions from positive and negative (organics evaporated from top QFF and adsorbed by bQFF) artifacts. Under both corrections, significant correlations (p < 0.05) were observed between log Kmp,OM and log Ktp,OM for the six selected SVOCs, suggesting that the predicted G/P partitioning can reasonably capture the measured G/P partitioning behavior. The large deviations (1-2 orders of magnitudes) between Kmp,OM and Ktp,OM for acenaphthenone and fluorenone might be caused by the assumption of ideality (activity coefficient = 1) and the over prediction of vapor pressures (for Ktp,OM calculation). Negative correlations were observed between regression residuals of log Kmp,OM vs. log Ktp,OM and relative humidity, which might be attributed to the use of a constant activity coefficient and the possibility of phase separation.

Xie, Mingjie; Hannigan, Michael P.; Barsanti, Kelley C.



Do Small, Neutral PAHs Survive in the ISM?  

NASA Astrophysics Data System (ADS)

Polycyclic aromatic hydrocarbon (PAH) molecules are ubiqutous in the universe. They reveal themselves primarily through emission features in the near- and mid-IR, commonly referred to as aromatic emission features (AEF) or the unidentified infrared (UIR) bands. We discovered the presence of small 3-4 ringed, neutral PAHs in the Red Rectangle (RR) through their blue fluorescence (Vijh et al. 2004; Vijh et al. 2005). The central star in the RR is in an active dust producing stage and these small PAHs are just being formed in the gas. Do these small PAHs survive under harsh interstellar conditions? Are the AEFs primarily due to larger PAHs? To answer these questions we have obtained long slit spectra of different reflection nebulae and star forming regions, where the temperatures of the illuminating stars cover a range from ˜ 9000 - 25000 K. We will present results that establish the presence or absence of blue fluorescence from small, neutral PAHs as a function of the local radiation field density. This research is funded by the NSF grant AST 0307307 to the University of Toledo. \\textbf{References} Vijh, U.P., Witt, A. N., & Gordon, K. D. 2004, ApJ, 606, L68 Vijh, U.P., Witt, A. N., & Gordon, K. D. 2005, ApJ (in press)

Vijh, U. P.; Witt, A. N.; Gordon, K. D.



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

NASA Technical Reports Server (NTRS)

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.

Hudgins, Douglas M.



Fish embryos are damaged by dissolved PAHs, not oil particles.  


To distinguish the toxicity of whole oil droplets from compounds dissolved in water, responses of zebrafish embryos exposed to particulate-laden, mechanically dispersed Alaska North Slope crude oil (mechanically dispersed oil (MDO)) were compared to those of embryos protected from direct oil droplet contact by an agarose matrix. Most polycyclic aromatic hydrocarbons (PAHs) in MDO were contained in oil droplets; about 16% were dissolved. The agarose precluded embryo contact with particulate oil but allowed diffusive passage of dissolved PAHs. The incidence of edema, hemorrhaging, and cardiac abnormalities in embryos was dose-dependent in both MDO and agarose and the biological effects in these compartments were identical in character. Although mean total PAH (TPAH) concentrations in MDO were about 5-9 times greater than in agarose, dissolved PAH concentrations were similar in the two compartments. Furthermore, mean differences in paired embryo responses between compartments were relatively small (14-23%, grand mean 17%), typically with a larger response in embryos exposed to MDO. Therefore, the embryos reacted only to dissolved PAHs and the response difference between compartments is explained by diffusion. Averaged over 48 h, the estimated mean TPAH concentration in agarose was about 16% less than the dissolved TPAH concentration in MDO. Thus, PAHs dissolved from oil are toxic and physical contact with oil droplets is not necessary for embryotoxicity. PMID:18479765

Carls, Mark G; Holland, Larry; Larsen, Marie; Collier, Tracy K; Scholz, Nathaniel L; Incardona, John P



Sedimentary organic biomarkers suggest detrimental effects of PAHs on estuarine microbial biomass during the 20th century in San Francisco Bay, CA, USA.  


Hydrocarbon contaminants are ubiquitous in urban aquatic ecosystems, and the ability of some microbial strains to degrade certain polycyclic aromatic hydrocarbons (PAHs) is well established. However, detrimental effects of petroleum hydrocarbon contamination on nondegrader microbial populations and photosynthetic organisms have not often been considered. In the current study, fatty acid methyl ester (FAME) biomarkers in the sediment record were used to assess historical impacts of petroleum contamination on microbial and/or algal biomass in South San Francisco Bay, CA, USA. Profiles of saturated, branched, and monounsaturated fatty acids had similar concentrations and patterns downcore. Total PAHs in a sediment core were on average greater than 20× higher above ?200cm than below, which corresponds roughly to the year 1900. Isomer ratios were consistent with a predominant petroleum combustion source for PAHs. Several individual PAHs exceeded sediment quality screening values. Negative correlations between petroleum contaminants and microbial and algal biomarkers - along with high trans/cis ratios of unsaturated FA, and principle component analysis of the PAH and fatty acid records - suggest a negative impacts of petroleum contamination, appearing early in the 20th century, on microbial and/or algal ecology at the site. PMID:25303655

Nilsen, Elena B; Rosenbauer, Robert J; Fuller, Christopher C; Jaffe, Bruce J



Degradation of polycyclic aromatic hydrocarbons (PAHs) in an aged coal tar contaminated soil under in-vessel composting conditions.  


In-vessel composting of polycyclic aromatic hydrocarbons (PAHs) present in contaminated soil from a manufactured gas plant site was investigated over 98 days using laboratory-scale in-vessel composting reactors. The composting reactors were operated at 18 different operational conditions using a 3-factor factorial design with three temperatures (T, 38 degrees C, 55 degrees C and 70 degrees C), four soil to green waste ratios (S:GW, 0.6:1, 0.7:1, 0.8:1 and 0.9:1 on a dry weight basis) and three moisture contents (MC, 40%, 60% and 80%). PAH losses followed first order kinetics reaching 0.015 day(-1) at optimal operational conditions. A factor analysis of the 18 different operational conditions under investigation indicated that the optimal operational conditions for degradation of PAHs occurred at MC 60%, S:GW 0.8:1 and T 38 degrees C. Thus, it is recommended to maintain operational conditions during in-vessel composting of PAH-solid waste close to these values. PMID:16246473

Antizar-Ladislao, Blanca; Lopez-Real, Joe; Beck, Angus James



Unlike PAHs from Exxon Valdez crude oil, PAHs from Gulf of Alaska coals are not readily bioavailable  

SciTech Connect

In the wake of the 1989 Exxon Valdez oil spill, spatially and temporally spill-correlated biological effects consistent with polycyclic aromatic hydrocarbon (PAH) exposure were observed. Some works have proposed that confounding sources from local source rocks, prominently coals, are the provenance of the PAHs. Representative coal deposits along the southeast Alaskan coast (Kulthieth Formation) were sampled and fully characterized chemically and geologically. The coals have variable but high total organic carbon content, technically classifying as coals and coaly shale, and highly varying PAH contents. Even for coals with high PAH content (4000 ppm total PAHs), a PAH-sensitive bacterial biosensor demonstrates nondetectable bioavailability as quantified, based on naphthalene as a test calibrant. These results are consistent with studies indicating that materials such as coals strongly diminish the bioavailability of hydrophobic organic compounds and support previous work suggesting that hydrocarbons associated with the regional background in northern Gulf of Alaska marine sediments are not appreciably bioavailable. 44 refs., 4 figs., 2 tabs.

Halambage Upul Deepthike; Robin Tecon; Gerry van Kooten; Jan Roelof van der Meer; Hauke Harms; Mona Wells; Jeffrey Short [Tennessee Technological University, Cookeville, TN (United States). Department of Chemistry



Removal efficiency of vapour/particulate phase PAHs by using alternative protective respirators in PAHs exposure workers.  


Due to the high heat environment in foundry industries, it is difficult for foundry workers to wear masks during their workday. Thus, how to prevent inhaling vapour or the particulate phase of polycyclic aromatic hydrocarbons (PAHs) is important for occupational hazard management. The present study assesses the characteristics of PAHs emission in foundry and plastic industries to evaluate the removal efficiencies of PAHs while workers use alternative personal protective equipment. The highest 1-hydroxypyrene (1-OHP) level was found for workers who used a cotton-fabric face mask (1.19 ?g/g creatinine) and activated-carbon face mask (1.16 ?g/g creatinine), compared to a lower level in workers who wore a surgical face mask (0.27 ?g/g creatinine) and a N95 respirator (0.51 ?g/g creatinine). The urinary 1-OHP in end-of-shift samples correlated to the airborne vapour phase Bapeq, but not for the particulate phase Bapeq in the foundry industry. This is probably because workers wore personal protective equipment that only removed the particulate phase PAH. The current study suggests that future work focus on developing an appropriate and comfortable respirator with high removal efficiency for ultrafine particulates and vapour phase PAHs simultaneously in PAH work environments. PMID:22525483

Chen, Hsiu-Ling; Yang, Chien-Hung; Lin, Ming-Hsiu



Genotoxic risk assessment in white blood cells of occupationally exposed workers before and after alteration of the polycyclic aromatic hydrocarbon (PAH) profile in the production material: comparison with PAH air and urinary metabolite levels  

Microsoft Academic Search

Objective: Workers in various industries can be exposed to polycyclic aromatic hydrocarbons (PAHs). The relationship between biomarkers of genotoxic risk, PAH compounds in air (ambient monitoring) and PAH metabolites in urine (internal exposure) were studied in 17 workers exposed to PAHs in a fireproof-material producing plant before and 3 months after the PAH profile was altered in the binding pitch. Methods:

B. Marczynski; R. Preuss; T. Mensing; J. Angerer; A. Seidel; A. El Mourabit; M. Wilhelm; T. Brüning



Biota – Sediment partitioning of aluminium smelter related PAHs and pulp mill related diterpenes by intertidal clams at Kitimat, British Columbia  

Microsoft Academic Search

The question of polycyclic aromatic hydrocarbon (PAH) bioavailability and its relationship to specific PAH sources with different PAH binding characteristics is an important one, because bioavailability drives PAH accumulation in biota and ultimately the biochemical responses to the PAH contaminants. The industrial harbour at Kitimat (British Columbia, Canada) provides an ideal location to study the bioavailability and bioaccumulation of sediment

Mark B. Yunker; Cara L. Lachmuth; Walter J. Cretney; Brian R. Fowler; Neil Dangerfield; Linda White; Peter S. Ross



Interspecies and interregional comparisons of the chemistry of PAHs and trace elements in mosses Hylocomium splendens (Hedw.) B.S.G. and Pleurozium schreberi (Brid.) Mitt. from Poland and Alaska  

USGS Publications Warehouse

Comparative biogeochemical studies performed on the same plant species in remote areas enable pinpointing interspecies and interregional differences of chemical composition. This report presents baseline concentrations of PAHs and trace elements in moss species Hylocomium splendens and Pleurozium schreberi from the Holy Cross Mountains (south-central Poland) (HCM) and Wrangell-Saint Elias National Park and Preserve (Alaska) and Denali National Park and Preserve (Alaska). Total PAH concentrations in the mosses of HCM were in the range of 473-2970 ??g kg-1 (dry weight basis; DW), whereas those in the same species of Alaska were 80-3390 ??g kg-1 DW. Nearly all the moss samples displayed the similar ring sequence: 3 > 4 > 5 > 6 for the PAHs. The 3 + 4 ring/total PAH ratios show statistically significant differences between HCM (0.73) and Alaska (0.91). The elevated concentrations of PAHs observed in some sampling locations of the Alaskan parks were linked to local combustion of wood, with a component of vehicle particle- and vapor-phase emissions. In HCM, the principal source of PAH emissions has been linked to residential and industrial combustion of coal and vehicle traffic. In contrast to HCM, the Alaskan mosses were distinctly elevated in most of the trace elements, bearing a signature of??the underlying geology. H.??splendens and P. schreberi showed diverse bioaccumulative capabilities of PAHs in all three study areas. ?? 2008 Elsevier Ltd.

Migaszewski, Z.M.; Galuszka, A.; Crock, J.G.; Lamothe, P.J.; Dolegowska, S.




EPA Science Inventory

Abstract The formation of polycyclic aromatic hydrocarbons (PAH) and soot has been investigated in atmospheric-pressure, laminar, ethane/oxygen/argon premixed flames as a function of mixture equivalence ratio. Mole fraction profiles of major products, trace aromatics, ...


Source apportionment of polycyclic aromatic hydrocarbons (PAHs) into Central Park Lake, New York City, over a century of deposition.  


Relative contributions of polycyclic aromatic hydrocarbons (PAHs) from combustion sources of wood, petroleum, and coal were computed in sediments from Central Park Lake in New York City (NY, USA) by chemical mass balance based on several reliable source indicators. These indicators are the ratio of retene to the sum of retene and chrysene, the ratio of 1,7-dimethylphenanthrene (DMP) to 1,7-DMP and 2,6-DMP, and the ratio of fluroanthene to fluroanthene and pyrene. The authors found that petroleum combustion-derived PAH fluxes generally followed the historical consumption data of New York State. Coal combustion-derived PAH flux peaked approximately in the late 1910s, remained at a relatively high level over the next 3 decades, then rapidly declined from the 1950s to the 1960s; according to historical New York State coal consumption data, however, there was a 2-peak trend, with peaks around the early 1920s and the mid-1940s. The 1940s peak was not observed in Central Park Lake, most likely because of the well-documented shift from coal to oil as the major residential heating fuel in New York City during the late 1930s. It was widely believed that the decreased PAH concentrations and fluxes in global sediments during the last century resulted from a major energy shift from coal to petroleum. The data, however, show that this shift occurred from 1945 through the 1960s and did not result in an obvious decline. The sharpest decrease, which occurred in the 1970s was not predominantly related to coal usage but rather was the result of multiple factors, including a decline in petroleum usage largely, the introduction of low sulfur-content fuel in New York City, and the introduction of emission-control technologies. PMID:24375577

Yan, Beizhan; Bopp, Richard F; Abrajano, Teofilo A; Chaky, Damon; Chillrud, Steven N




PubMed Central

Relative contributions of polycyclic aromatic hydrocarbons (PAHs) from combustion sources of wood, petroleum, and coal were computed in sediments from Central Park Lake in New York City (NY, USA) by chemical mass balance based on several reliable source indicators. These indicators are the ratio of retene to the sum of retene and chrysene, the ratio of 1,7-dimethylphenanthrene (DMP) to 1,7-DMP and 2,6-DMP, and the ratio of fluroanthene to fluroanthene and pyrene. The authors found that petroleum combustion–derived PAH fluxes generally followed the historical consumption data of New York State. Coal combustion-derived PAH flux peaked approximately in the late 1910s, remained at a relatively high level over the next 3 decades, then rapidly declined from the 1950s to the 1960s; according to historical New York State coal consumption data, however, there was a 2-peak trend, with peaks around the early 1920s and the mid-1940s. The 1940s peak was not observed in Central Park Lake, most likely because of the well-documented shift from coal to oil as the major residential heating fuel in New York City during the late 1930s. It was widely believed that the decreased PAH concentrations and fluxes in global sediments during the last century resulted from a major energy shift from coal to petroleum. The data, however, show that this shift occurred from 1945 through the 1960s and did not result in an obvious decline. The sharpest decrease, which occurred in the 1970s was not predominantly related to coal usage but rather was the result of multiple factors, including a decline in petroleum usage largely, the introduction of low sulfur–content fuel in New York City, and the introduction of emission-control technologies. PMID:24375577

Yan, Beizhan; Bopp, Richard F.; Abrajano, Teofilo A.; Chaky, Damon; Chillrud, Steven N.



Theoretical quantum chemical study of protonated - deuteronated PAHs: Interstellar implications  

NASA Astrophysics Data System (ADS)

Diffuse Interstellar Bands (DIBs) are optical absorption features on the interstellar extinction curve. Ultra-high resolution spectroscopic observations suggest that at least some of these features are due to large molecules. Observational results also reveal that the strengths of the DIBs are not strongly correlated with each other, implying that there must be several carriers. Considering the wide range of interstellar species and the cost and duration of experimental work that is involved to determine the carriers of DIBs, Density Functional Theory (DFT) and Time Dependent Density Functional Theory (TDDFT) calculations offer opportunities to investigate which molecules are suitable for laboratory studies. The widespread presence of Polycyclic Aromatic Hydrocarbons (PAHs) in astrophysical environments is known from observations of the Unidentified Infrared (UIR) emission bands. Since PAHs are stable enough to be present under interstellar conditions, they are good candidates to be the carriers of the DIBs. We report DFT and TDDFT calculations to predict electronic transitions of neutral as well as protonated-deuteronated PAHs with various sites of protonation and deuteronation. The PAH molecules considered for calculation include pyrene, perylene, coronene and heptacene. Compared to their neutral forms, these charged isoelectronic forms of PAHs are predicted to have active transitions in the visible region, which means they are suitable candidates as carriers for some of the DIBs.

Buragohain, Mridusmita; Pathak, Amit; Hammonds, Mark; Sarre, Peter J.



The Relationship Between PAHs and the Interstellar Medium  

NASA Astrophysics Data System (ADS)

The question as to whether polycyclic aromatic hydrocarbon (PAH) emission traces star formation or ISM content is still an open one. We investigate the relationship between PAHs and the ISM using data from the Spitzer Infrared Nearby Galaxy Survey (SINGS). In particular, we make point-to-point comparisions of continuum subtracted 8 micron emission with tracers of the ISM including stellar extinction and CO. These comparisons span a range of environments, from the strong UV fields surrounding high star formation regions, to the less active interarm environments of spiral galaxies where a more diffuse PAH component is seen. The observed relationships are presented for NGC 0628, NGC 3627, NGC 4736, NGC 5194 and NGC 6946, these galaxies selected from the SINGS sample to span a range of morphologies from Sab to Scd.

Meyer, M. J.; Regan, M.; Calzetti, D.; Kennicutt, R. C.; Walter, F.; Thornley, M. D.; Bendo, G.; Armus, L.; Dale, D. A.; Draine, B.; Engelbracht, C.; Gordon, K.; Grauer, A. D.; Helou, G.; Hollenbach, D. J.; Kewley, L. J.; Leitherer, C.; Murphy, E.; Jarrett, T. H.; Li, A.; Malhotra, S.; Rieke, G. H.; Rieke, M. J.; Roussel, H.; Smith, J. D.



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


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

d'Hendecourt, L; Ehrenfreund, P



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

PubMed Central

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

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



Experimental study on the removal of PAHs using in-duct activated carbon injection.  


This paper presents the incineration tests of municipal solid waste (MSW) in a fluidized bed and the adsorption of activated carbon (AC) on polycyclic aromatic hydrocarbons (PAHs). An extraction and high performance liquid chromatography (HPLC) technique was used to analyze the concentrations of the 16 US EPA specified PAHs contained in raw MSW, flue gas, fly ash, and bottom ash. The aim of this work was to decide the influence of AC on the distribution of PAHs during the incineration of MSW. Experimental researches show that there were a few PAHs in MSW and bottom ash. With the increase of AC feeding rate, the concentrations of three- to six-ring PAHs in fly ash increased, and the concentration of two-ring PAH decreased. The total-PAHs in flue gas were dominated by three-, and four-ring PAHs, but a few two-, five-ring PAHs and no six-ring PAHs were found. PAHs could be removed effectively from flue gas by using in-duct AC injection and the removal efficiencies of PAHs were about 76-91%. In addition, the total toxic equivalent (TEQ) concentrations of PAH in raw MSW, bottom ash, fly ash, and flue gas were 1.24 mg TEQ kg-1, 0.25 mg TEQ kg-1, 6.89-9.67 mg TEQ kg-1, and 0.36-1.50 microg TEQ Nm-3, respectively. PMID:15811415

Zhou, Hong-Cang; Zhong, Zhao-Ping; Jin, Bao-Sheng; Huang, Ya-Ji; Xiao, Rui



Lightning Ratios  

NSDL National Science Digital Library

Using satellites and ground-based detection instruments, researchers have now mapped out lightning ratios for the continental United States. The Lightning Ratios site, from Space Science News (NASA), provides recent data in the form of a vibrant color map (.pdf or .jpg) of cloud-to-cloud lightning to cloud-to-ground lightning over the continental United States.


Rod Ratios  

NSDL National Science Digital Library

This activity builds student knowledge of ratios by using Cuisenaire rods to determine proportion and form equivalent ratios. Students may use the Cuisenaire rod environment embedded in this resource or they may use actual Cuisenaire rods depending on preference/ability/accessibility. This resource includes teacher notes, solution, and suggestions for questioning.

Team, Nrich



Enhanced sorption of PAHs in natural-fire-impacted sediments from Oriole Lake, California.  


Surface sediment cores from Oriole Lake (CA) were analyzed for organic carbon (OC), black carbon (BC), and their ?(13)C isotope ratios. Sediments displayed high OC (20-25%) and increasing BC concentrations from ?0.40% (in 1800 C.E.) to ?0.60% dry weight (in 2000 C.E.). Petrographic analysis confirmed the presence of fire-derived carbonaceous particles/BC at ?2% of total OC. Natural fires were the most likely cause of both elevated polycyclic aromatic hydrocarbon (PAH) concentrations and enhanced sorption in Oriole Lake sediments prior to 1850, consistent with their tree-ring-based fire history. In contrast to other PAHs, retene and perylene displayed decreasing concentrations during periods with natural fires, questioning their use as fire tracers. The occurrence of natural fires, however, did not result in elevated concentrations of black carbon or chars in the sediments. Only the 1912-2007 sediment layer contained anthropogenic particles, such as soot BC. In this layer, combining OC absorption with adsorption to soot BC (using a Freundlich coefficient n = 0.7) explained the observed sorption well. In the older layers, n needed to be 0.3 and 0.5 to explain the enhanced sorption to the sediments, indicating the importance of natural chars/inertinites in sorbing PAHs. For phenanthrene, values of n differed significantly between sorption to natural chars (0.1-0.4) and sorption to anthropogenic black carbon (>0.5), suggesting it could serve as an in situ probe of sorbents. PMID:21405084

Sullivan, Julia; Bollinger, Kevyn; Caprio, Anthony; Cantwell, Mark; Appleby, Peter; King, John; Ligouis, Bertrand; Lohmann, Rainer



Biodegradation of PAHs and PCBs in soils and sludges  

USGS Publications Warehouse

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 active-passive biotreatment can be a cost-effective approach for remediation of highly hydrophobic organic contaminants. The mathematical model proposed here would be useful in the design and operation of such organic chemical biodegradation processes on remediation sites. ?? 2007 Springer Science+Business Media B.V.

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




E-print Network

for LCSQA. PAH compounds consist of two or more fused benzene rings in linear, angular or cluster fossil fuels and other organic material. PAH are found in the atmosphere in very small quantities (ng/m3

Paris-Sud XI, Université de



EPA Science Inventory

Assessing the risks of PAHs to aquatic organisms requires consideration of several factors. First, environmental PAH concentrations must be characterized, including chemical partitioning information important to bioavailability. Second, UV radiation exposures must be evaluated re...



EPA Science Inventory

Polycyclic aromatic hydrocarbons (PAHs) represent a group of organic contaminants known for their prevalence and persistence in petroleum-impacted environment such as groundwater, soils and sediments. Many high molecular weight PAHs are suspected carcinogens and the existence of...



EPA Science Inventory

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants introduced through combustion processes and from release of petroleum and petroleum products. Assessing the ecological risk from PAHs is complicated by several factors, including their occurrence a...



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...


Interactions between soil fractions and PAH compounds in thermal desorption of contaminated soils  

SciTech Connect

Results are reported for the interactions between three fractions of a soil, namely fulvic acid (FA), humic acid (HA) and humic/inorganic fractions, and three polynuclear aromatic hydrocarbons (PAHs). Prepared PAH+soil fraction mixtures, with 0.8-7.0 mass% PAH, were tested using a differential scanning calorimeter (DSC) over a temperature range of 20-390{degrees}C. The DSC results for the PAH+HA mixtures showed distinctly different characteristics than the other two soil fractions, where the endothermic peak for the vaporization of the PAH was absent. With the aid of flash calculations, the absence of the vaporization peak is interpreted to be due to the liquid-phase miscibility of the PAHs and the HA fraction. The miscible behavior of HA+PAHs implies that the temperature necessary for complete removal of a PAH would be higher than its boiling point temperature. 7 refs., 6 figs.

Mehrotra, A.K.; Svrcek, W.Y. [Univ. of Calgary, Alberta (Canada); Maguire, V. [Amoco Canada Petroleum Co., Ltd., Calgary (Canada)



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

USGS Publications Warehouse

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.

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



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

Microsoft Academic Search

This work investigated the PAHs generated in a waste-tire pyrolysis process and the PAHs removal by a wet scrubber (WSB) and a flare. IND, DBA, and BaP were found to dominate in the powders of scrap tires before the pyrolysis. The PAHs in the carbon blacks formed in the pyrolysis were mainly 2-, 3-, 6-, and 7-ring PAHs. Nap was

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



Temporal variations in PAH concentrations in Quercus ilex L. (holm oak) leaves in an urban area.  


Temporal variations of polycyclic aromatic hydrocarbon (PAH) concentrations in leaves of a Mediterranean evergreen oak, Quercus ilex L., were investigated in order to assess the suitability of this species to biomonitor PAH air contamination. Leaf samples were collected at six sites of the urban area of Naples (Italy) and at a control site in the Vesuvius National Park, in May and September 2001, and in January and May 2002. PAH extraction was conducted by sonication in dichloromethane-acetone and quantification by GC-MS. In winter, leaf total PAH concentrations showed, at all the urban sites, values 2-fold higher than in all the other samplings, reflecting the temporal trend reported for PAH air contamination in the Naples urban area. Moreover, leaf PAH concentrations showed, at all the urban sites, a decrease in May 2002 after the winter accumulation. At the control site leaf PAH concentrations showed lower values and smaller temporal variations than at the urban sites. The findings support the suitability of Q. ilex leaves to monitor temporal variations in PAH contamination. The highest winter concentrations of total PAHs were due to the medium molecular weight PAHs that increased with respect to both low and high molecular weight PAHs. The medium molecular weight PAHs showed the same temporal trend both at the urban and remote sites. PMID:16182861

De Nicola, Flavia; Maisto, Giulia; Prati, Maria Vittoria; Alfani, Anna



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

NASA Astrophysics Data System (ADS)

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

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


Study on the Degradation of Polycyclic Aromatic Hydrocarbons (PAHs) in the Excrement of Marphysa sanguinea  

Microsoft Academic Search

To clarify the degradation of polycyclic aromatic hydrocarbons (PAHs) in the environment, we measured the PAH concentration in fecal pellets excreted by the annelid, Marphysa sanguinea, in a tidal flat and investigated the time dependence of the concentration. The degradation of PAHs in the annelid's excrement approximately obeyed a pseudo first-order rate equation for initial 2 h. The half-lives of




Metallicity Effects on Mid-Infrared Colors and the 8 ?m PAH Emission in Galaxies  

NASA Astrophysics Data System (ADS)

We examine colors from 3.6 to 24 ?m as a function of metallicity (O/H) for a sample of 34 galaxies. The galaxies range over 2 orders of magnitude in metallicity. They display an abrupt shift in the 8 ?m-to-24 ?m color for metallicities between one-third and one-fifth of the solar value. The mean 8-to-24 ?m flux density ratio below and above 12+log(O/H)=8.2 is 0.08+/-0.04 and 0.70+/-0.53, respectively. We use mid-IR colors and spectroscopy to demonstrate that the shift is primarily due to a decrease in the 8 ?m flux density, as opposed to an increase in the 24 ?m flux density. This result is most simply interpreted as being due to a weakening at low metallicity of the mid-IR emission bands usually attributed to PAHs (polycyclic aromatic hydrocarbons) relative to the small-grain dust emission. However, existing empirical spectral energy distribution models cannot account for the observed short-wavelength (below 8 ?m) colors of the low-metallicity galaxies merely by reducing the strength of the PAH features; some other emission source (e.g., hot dust) is required.

Engelbracht, C. W.; Gordon, K. D.; Rieke, G. H.; Werner, M. W.; Dale, D. A.; Latter, W. B.



Understanding the Complexity and Strategic Evolution in PAH Remediation Research  

Microsoft Academic Search

The development and improvement of society through industrialization and urbanization comes with the cost of consistent deterioration and degradation of the natural environment through generation of toxic and hazardous pollutants. Polycyclic aromatic compounds (PAHs) are a major class of such persistent organic pollutants, posing serous threat to terrestrial and aquatic ecosystems due to their intrinsic low aqueous solubility, higher binding

Biswanath Mahanty; Kannan Pakshirajan; Veeranki Venkata Dasu



Pyrogenic molecular markers: Linking PAH with BPCA analysis.  


Molecular characterization of pyrogenic organic matter (PyOM) is of great interest to understand the formation and behavior of these increasingly abundant materials in the environment. Two molecular marker methods have often been used to characterize and trace PyOM: polycyclic aromatic hydrocarbon (PAH) and benzenepolycarboxylic acid (BPCA) analysis. Since both methods target pyrogenic polycyclic compounds, we investigated the linkages between the two approaches using chars that were produced under controlled conditions. Rye and maize straws and their analogues charred at 300, 400 and 500°C, respectively, were thus analyzed with both methods. Moreover, we also measured BPCAs directly on the lipid extracts, on which PAHs were analyzed, and on the respective extraction residues, too. Both methods revealed important features of the chars, in particular the increasing degree of aromatic condensation with increasing highest heating temperature (HTT). The overlap between the two methods was identified in the lipid fraction, where the proportion of benzenetricarboxylic acids (B3CAs) correlated with PAH abundance. The results confirmed the validity and complementarity of the two molecular marker methods, which will likely continue to play a crucial role in PyOM research due to the recent developments of compound-specific PAH and BPCA stable carbon (?(13)C) and radiocarbon ((14)C) isotope methods. PMID:25084061

Wiedemeier, Daniel B; Brodowski, Sonja; Wiesenberg, Guido L B




EPA Science Inventory

This study was designed to evaluate several treatments for their ability to enhance the biological removal of polycyclic aromatic hydrocarbons (PAHs) from contaminated soil and sediment. Previously land-treated material was used to test the treatments in a 13 week bench scale stu...


Are Biogenic PAHs Precursors for Fullerenes on Earth?  

NASA Astrophysics Data System (ADS)

C60 fullerene in shungite and in bitumen from the Bohemian Massif could have formed in situ in two steps: 1. Cyclotrimerization of the PAH C20H12. 2. Dehydrogenation of C60H30 to C60. The necessary heat was provided during metamorphism.

Heymann, D.



Levels, trends and health concerns of atmospheric PAHs in Europe  

NASA Astrophysics Data System (ADS)

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.

Garrido, Adrián; Jiménez-Guerrero, Pedro; Ratola, Nuno




EPA Science Inventory

Concentrations of polycyclic aromatic hydrocarbons were measured in nine day care centers in the spring of 1997. Indoor and outdoor air, food and beverages, indoor dust, and outdoor play area soil were sampled. The mean sums of 20 target PAH concentrations were 265 and 199 ng...


Human Exposures to PAHs: an Eastern United States Pilot Study  

EPA Science Inventory

Personal exposure monitoring for select polycyclic aromatic hydrocarbons (PAHs) was performed as part of the National Human Exposure Assessment Survey (NHEXAS) Pilot Study in Baltimore, MD and in four surrounding counties (NHEXAS-Maryland). An objective of this effort was to esta...


Structural characterisation of humic acid-bound PAH residues in soil by 13C-CPMAS-NMR-spectroscopy: evidence of covalent bonds.  


The fate of 13C-labelled phenanthrene and fluoranthene in different soil systems during biodegradation was studied. The soil humic acid fraction was isolated followed by structural characterisation using 13C-cross polarisation magic angle spinning nuclear magnetic resonance spectroscopy (13C-CPMAS-NMR). It could be demonstrated that especially the ratio between the concentrations of polycyclic aromatic hydrocarbons (PAHs) and soil humus matrix limits the usefulness of this analytical tool. Based on these results a ratio of 13C-activity(PAH)/13C-activity(soil) approximately 1.5/1.0 in the test material was suggested. The chemical transformation of a PAH and its bound residue formation in a soil system detected by changes of chemical shifts in the 13C-NMR spectrum was proven for the first time. Structural information obtained by NMR spectra were verified by alkaline hydrolysis of PAH/humus-associations and following identification of cleavage products. Ester-bound phenanthrene metabolites such as 1-hydroxy-2-naphthoic acid, ortho-phthalic acid and 3,4-dihydroxybenzoic acid were detected. Additional structural assignments indicated the presence of ether-bound phenanthrene derivatives as well. Using isotopic labelling techniques a quantitative evaluation of bound residue distribution was undertaken. Fifty to seventy percent of phenanthrene metabolites which could be related to the added 13C(1)-phenanthrene were ester bound via their carboxyl groups. PMID:12137049

Käcker, Thomas; Haupt, Erhard T K; Garms, Christian; Francke, Wittko; Steinhart, Hans



Diagnostic Immunopathology  

PubMed Central

The application of immunologic techniques to tissue sections has added a new dimension to the investigation and classification of various processes. Virtually every section of diagnostic pathology has been enhanced by using specific monoclonal antibodies or polyclonal antiserum. Neoplasms formerly diagnosed as poorly differentiated or anaplastic may be precisely identified as to their origin through the use of specific membrane or cytoplasmic markers. Other cellular products, including viruses, hormones, enzymes or highly specific proteins, are also available to study neoplastic and nonneoplastic processes. New and more specific reagents are regularly becoming available for the diagnostic repertoire of pathologists. We present some of the principles of diagnostic immunopathology to show the scope and importance of the techniques. ImagesFigure 2.Figure 3. PMID:3529633

Cancilla, Pasquale A.; Cochran, Alistair J.; Naeim, Faramarz; Said, Jonathan W.




SciTech Connect

The effects of the pi-coordination of an Fe atom on the mid- and far-infrared spectra of a mixture of cationic polycyclic aromatic hydrocarbons (PAHs), e.g., pyrene (C{sub 16}H{sub 10}), anthanthrene (C{sub 22}H{sub 12}), coronene (C{sub 24}H{sub 12}), ovalene (C{sub 32}H{sub 14}), circumpyrene (C{sub 42}H{sub 16}), and circumcoronene (C{sub 54}H{sub 18}), are studied by Density Functional Theory based calculations. In the mid-infrared range (3-20 {mu}m), by comparison with the bare PAH{sup +} spectrum, we found (1) an increase of the intensity ratio of the C-H stretching and C-H out-of-plane bending bands with respect to the intense CC stretching band and (2) a shift of the band positions and a characteristic profile with a steep blue rise and an extended red tail for the CC stretching and CH out-of-plane bending bands. None of these features appears inconsistent with the observed aromatic infrared band spectrum. In the far-infrared range (lambda > 20 {mu}m), the presence of a pi-coordinated Fe atom induces many new bands as (1) some vibrational modes of the PAH are activated due to symmetry reduction and (2) new modes involving the motion of the Fe atom occur. In particular, an accumulation point due to the activation of the Fe-PAH stretching mode is observed at around 40 {mu}m. This range is suggested to contain the spectral fingerprint for the presence of [M-PAH]{sup +} (M=Fe, Si, Mg) complexes in the interstellar medium. Additional features in the [60-300] {mu}m range are found for complexes with large PAHs. The obtained results are discussed in the light of past, present, and future astronomical missions, among which are the Herschel Space Observatory and the SPICA telescope for the far-infrared domain.

Simon, A.; Joblin, C. [Universite de Toulouse, UPS, CESR, 9 Av. du Colonel Roche, 31028 Toulouse Cedex 4, France. (France)



Particulate PAHs observed in the surrounding of a municipal incinerator  

NASA Astrophysics Data System (ADS)

An intensive sampling campaign was undertaken in the surroundings of a municipal waste incinerator located in a French great urban centre in order to evaluate the impact of particles emissions on the ambient air and to estimate the exposure levels to toxic or carcinogenic compounds for a population living in the neighbourhood of this incinerator. To minimise the effect of industrial and road activities, sampling was performed during the 2 days of a weekend and on Monday morning. Different operating modes of the incinerator were investigated: (i) normal incinerator functioning and (ii) maintenance activity of the combustion chamber corresponding to the stop and cooling furnace periods. Particulate polycyclic aromatic hydrocarbons (PAHs) and total particulate carbon concentrations were determined in three sites situated, respectively, close to the incinerator, 2 km downwind and 1 km upwind of the plant. In normal operating mode similar concentrations were observed in the three sites. During the furnace stop an increase of total PAH concentrations was observed in the sampling site close to the incinerator. The concentration was 3 times higher than those measured in the other two sampling sites. But this increase was limited in time and in space since this phenomenon is only observed in the vicinity of the incinerator. The study of PAH profiles indicated that Pyrene and Retene showed the highest enhancement of their relative concentrations. The influence of incinerator functioning parameters on the PAHs concentrations is discussed. The furnace temperature and the mode of exhaust fumes seem to be deciding parameters to explain the increase of PAH level in the incinerator site. However, the incinerator emissions remained a minor part of the atmospheric pollution in the urban area.

Besombes, Jean-Luc; Ma??tre, Anne; Patissier, Olivier; Marchand, Nicolas; Chevron, Nathalie; Stoklov, Muriel; Masclet, Pierre


Plasma processing of interstellar PAHs into solar system kerogen  

NASA Technical Reports Server (NTRS)

Processes resulting in the formation of hydrocarbons of carbonaceous chondrites and the identity of the interstellar molecular precursors involved are an objective of investigations into the origin of the solar system and perhaps even life on earth. We have combined the resources and experience of an astronomer and physicists doing laboratory simulations with those of a chemical expert in the analysis of meteoritic hydrocarbons, in a project that investigated the conversion of polycyclic aromatic hydrocarbons (PAHs) formed in stellar atmospheres into alkanes found in meteorites. Plasma hydrogenation has been found in the University of Alabama at Birmingham Astrophysics Laboratory to produce from the precursor PAH naphthalene, a new material having an IR absorption spectrum (Lee, W. and Wdowiak, T.J., Astrophys. J. 417, L49-L51, 1993) remarkably similar to that obtained at Arizona State University of the benzene-methanol extract of the Murchison meteorite (Cronin, J.R. and Pizzarello, S., Geochim. Cosmochim. Acta 54, 2859-2868, 1990). There are astrophysical and meteoritic arguments for PAH species from extra-solar sources being incorporated into the solar nebula, where plasma hydrogenation is highly plausible. Conversion of PAHs into alkanes could also have occurred in the interstellar medium. The synthesis of laboratory analogs of meteoritic hydrocarbons through plasma hydrogenation of PAH species is underway, as is chemical analysis of those analogs. The objective is to clarify this heretofore uninvestigated process and to understand its role during the origin of the solar system as a mechanism of production of hydrocarbon species now found in meteorites. Results have been obtained in the form of time-of-flight spectroscopy and chemical analysis of the lab analog prepared from naphthalene.

Wdowiak, T. J.; Lee, W.; Cronin, J.; Beegle, L. W.; Robinson, M. S.



Characteristics and sources of atmospheric polycyclic aromatic hydrocarbons (PAHs) in Shanghai, China.  


A field campaign was conducted to measure and analyze 13 polycyclic aromatic hydrocarbons (PAHs) in six major zones in the city of Shanghai, P.R. China from August 2006 to April 2007. Ambient air samples were collected seasonally using passive air samplers, and gas chromatography-mass spectroscopy was used in this field campaign. The results showed that there was a sequence of 13 PAHs at Phen > FA > Pyr > Chr > Fl > An > BaA > BbFA > BghiP > IcdP > BkFA > BaP > DahA and the sum of these PAHs is 36.01 +/- 10.85 ng/m(3) in gas phase. FL, Phen, FA, Pyr, and Chr were the dominant PAHs in gas phase in the city. They contributed 90% of total PAHs in the gas phase. Proportion of measured PAHs with three, four, five, and six rings to total PAHs was 53%, 42%, 3%, and 2%, respectively. The highest concentration of SigmaPAHs (the sum of 13 PAHs) occurred in the wintertime and the lowest was in the summer. This investigation suggested that traffic, wood combustion, and metal scrap burn emissions were dominant sources of the concentrations of PAHs in six city zones compared with coal burning and industry emissions. Further, the traffic emission sources of PAHs in the city were attributed mostly to gasoline-powered vehicles compared with diesel-powered vehicles. It was revealed that the seasonal changes in PAHs in the city depended on different source types. Metal scrap burn was found to be the major source of PAHs during the autumn, while the PAH levels in the atmosphere for winter and spring seasons were mainly influenced by wood and biomass combustion. Comparisons of PAHs among different city zones and with several other cities worldwide were also made and discussed. PMID:19440848

Wang, Xian Yu; Li, Qing Bo; Luo, Yong Ming; Ding, Qian; Xi, Lian Min; Ma, Jian Min; Li, Yan; Liu, Yi Peng; Cheng, Cui Li



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

NASA Astrophysics Data System (ADS)

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 ?m. 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.

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



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

NASA Astrophysics Data System (ADS)

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.

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




SciTech Connect

We study the polycyclic aromatic hydrocarbon (PAH) bands, ionic emission lines, and mid-infrared continuum properties in a sample of 171 emission line galaxies taken from the literature plus 15 new active galactic nucleus (AGN) Spitzer spectra. We normalize the spectra at {lambda} = 23 {mu}m and grouped them according to the type of nuclear activity. The continuum shape steeply rises for longer wavelengths and can be fitted with a warm blackbody distribution of T {approx} 150-300 K. The brightest PAH spectral bands (6.2, 7.7, 8.6, 11.3, and 12.7 {mu}m) and the forbidden emission lines of [Si II] 34.8 {mu}m, [Ar II] 6.9 {mu}m, [S III] 18.7 and 33.4 {mu}m were detected in all the starbursts and in {approx}80% of the Seyfert 2. Taking under consideration only the PAH bands at 7.7 {mu}m, 11.3 {mu}m, and 12.7 {mu}m, we find that they are present in {approx}80% of the Seyfert 1, while only half of this type of activity show the 6.2 {mu}m and 8.6 {mu}m PAH bands. The observed intensity ratios for neutral and ionized PAHs (6.2 {mu}m/7.7 {mu}m x 11.3 {mu}m/7.7 {mu}m) were compared to theoretical intensity ratios, showing that AGNs have higher ionization fraction and larger PAH molecules ({>=}180 carbon atoms) than SB galaxies. The ratio between the ionized (7.7 {mu}m) and the neutral PAH bands (8.6 {mu}m and 11.3 {mu}m) are distributed over different ranges for AGNs and SB galaxies, suggesting that these ratios could depend on the ionization fraction, as well as on the hardness of the radiation field. The ratio between the 7.7 {mu}m and 11.3 {mu}m bands is nearly constant with the increase of [Ne III]15.5 {mu}m/[Ne II] 12.8 {mu}m, indicating that the fraction of ionized to neutral PAH bands does not depend on the hardness of the radiation field. The equivalent width of both PAH features show the same dependence (strongly decreasing) with [Ne III]/[Ne II], suggesting that the PAH molecules, emitting either ionized (7.7 {mu}m) or neutral (11.3 {mu}m) bands, may be destroyed with the increase of the hardness of the radiation field.

Sales, Dinalva A.; Pastoriza, M. G.; Riffel, R., E-mail: dinalva.aires@ufrgs.b, E-mail: pastoriza@ufrgs.b, E-mail: riffel@ufrgs.b [Departamento de Astronomia, Universidade Federal do Rio Grande do Sul. Av. Bento Goncalves 9500, Porto Alegre, RS (Brazil)



Emission of Pb and PAHs from thermally co-treated MSWI fly ash and bottom ash process.  


Municipal solid waste incinerator (MSWI) fly ash was regarded as a hazardous material because concentrations of TCLP leaching solution exceeded regulations. Previous studies have investigated the characteristics of thermally treated slag. However, the emissions of pollutant during the thermal treatment of MSWI fly ash have seldom been addressed. The main objective of this study was to evaluate the emission of Pb and PAHs from thermally co-treated MSWI fly and bottom ash process. The experimental parameters included the form of pretreatment, the proportion of bottom ash (bottom ash/fly ash, B/F=0, 0.1 and 1) and the retention time. The toxicity of thermally treated slag was also analyzed. The results indicated that (1) Pb emission occurred only in the solid phase and that PAHs were emitted from both solid and gas phases during thermal treatment process. (2) Washing pretreatment reduced not only the TCLP leaching concentration of Pb (from 15.75 to 1.67 mg/L), but also the emission of PAHs from the solid phase during thermal treatment process. (3) Adding bottom ash reduced the TCLP leaching concentration of thermally treated slag. (4) The concentration of Pb emission increased with retention time. (5) The thermal treatment reduced the toxicity of raw fly ash effectively, the inhibition ratio of raw fly ash and thermal treated slag were 98.71 and 18.35%, respectively. PMID:17521803

Chou, Jing-Dong; Wey, Ming-Yen; Chang, Shih-Hsien



Combined use of PAH levels and EROD activities in the determination of PAH pollution in flathead mullet (Mugil cephalus) caught from the West Black Sea coast of Turkey.  


The aim of this study was to determine the extent of polycyclic aromatic hydrocarbon (PAH) pollution by measuring PAH levels and 7-ethoxyresorufin-O-deethylase (EROD) activities in flathead mullet (Mugil cephalus) samples caught from the West Black Sea coast of Turkey. The fish samples were caught in August 2008-2011. The levels of 13 PAHs were measured by high-performance liquid chromatography (HPLC) in the liver of fish. Most of the measured PAHs had three rings (low molecular weight). The frequencies of detection of PAHs were higher in fish samples caught from Zonguldak Harbour and Gülüç Stream Mouth than those from Sakarya River Mouth, Amasra and Kefken. EROD activities and cytochrome P4501A (CYP1A) protein level were also measured in the fish liver microsomes. Highly elevated EROD activities and CYP1A levels were measured in the mullet samples caught from Zonguldak Harbour and Gülüç Stream than those from Amasra and Kefken. The detection of PAHs in the liver of fish samples shows recent exposure to PAHs. The chemical analyses of PAHs and EROD activity results together reflected the extent of PAH pollution in the livers of fish caught from the West Black Sea coast of Turkey. The results indicate that Zonguldak Harbour is the most polluted site in the West Black Sea coast of Turkey. PMID:25339526

Bozcaarmutlu, Azra; Sapmaz, Canan; Kaleli, Gizem; Turna, Sema; Yenisoy-Karaka?, Serpil



Hydrocarbon, PAH and PCB emissions from ferries: A case study in the Skagerak-Kattegatt-Öresund region  

NASA Astrophysics Data System (ADS)

Hydrocarbon speciation measurements have been carried out on board two passenger ferries (medium speed, four-stroke diesel main engines) operating in the Skagerak-Kattegatt-Öresund region. Average emission factors for 20 light-weight hydrocarbons (C 2-C 6), 12 medium-weight hydrocarbons (C 6-C 12), 23 polycyclic aromatic hydrocarbons (PAH), 7 polychlorinated biphenyls (PCB) and hexachlorbenzene (HCB) were determined for a situation with varying engine loads and a short service route ( MS Aurora, Helsingborg-Helsingor) and a case with a longer service route and more constant engine loads ( Stena Danica, Goteborg-Fredrikshavn). In general, ethene, propene, isobutene, benzene and C 9?C 12 alkanes dominated the hydrocarbon compositions measured, although their relative proportions differed between the two ferries. The PCB emissions measured were relatively small which is probably a reflection of the low Cl content in the fuel and gas oils used. The levels of PAH detected appear, however, to be of significance; the total PAH group accounted for ca. 1 % of the total hydrocarbon emission. It is roughly estimated that ferry traffic in the Skagerak-Kattegatt-Öresund region accounts for ca. 5 t PAH and ca. 1 kg PCB per year. In line with previous estimates of marine emissions, NO x emissions from the ferries were quite significant and this represents an important source in the study area. Since average hydrocarbon emission rates were only ca. 1 % of the NO x emissions, tropospheric ozone formation will be more dependent on the NO x emissions irrespective of the composition of the emitted hydrocarbons. In addition, the low HC/NO x ratio in the emissions also indicates that the possible contribution of ferry traffic emissions to hydrocarbon measurements at coastal stations is not very significant.

Cooper, D. A.; Peterson, K.; Simpson, D.


Polynuclear aromatic hydrocarbons (PAHs) mediate cadmium toxicity to an emergent wetland species.  


Growth and pollutant removal by emergent wetland plants may be influenced by interactions among mixed pollutants in constructed wetlands. A glasshouse experiment was conducted to investigate interactive effects of cadmium (Cd) × polynuclear aromatic hydrocarbons (PAHs) × plant treatments on growth of Juncus subsecundus, Cd and PAH removal from soil and the total number of microorganisms in soil. Growth and biomass of J. subsecundus were significantly influenced by interaction of Cd and PAHs, significantly decreasing with either Cd or PAH additions, but with the effect of Cd on plant growth being stronger than that of PAHs. The mixture of low Cd and low PAH lessened Cd toxicity to plants, resulting in improved plant growth and increased Cd accumulation in plant tissues, thus enhancing Cd removal by plants. The dissipation of PAHs in soils was significantly influenced by interactions of Cd, PAH and plant presence or absence. The total number of microorganisms in soils was significantly increased by the PAH additions. The interactive effect of Cd and PAHs on plant growth may be linked to the changes in the abundance of microorganisms in the rhizosphere, probably via a positive effect of PAH metabolites and/or phytohormones produced by microorganisms on plant growth. PMID:21367520

Zhang, Zhenhua; Rengel, Zed; Meney, Kathy; Pantelic, Ljiljana; Tomanovic, Radmila



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

PubMed Central

Polycyclic aromatic hydrocarbons (PAHs) are combustion products of organic materials, mixtures of which contain multiple known and probable human carcinogens. PAHs occur in indoor and outdoor air, as well as in char-broiled meats and fish. Human exposure to PAHs occurs by inhalation, ingestion and topical absorption, and subsequently formed metabolites are either rendered hydrophilic and excreted, or bioactivated and bound to cellular macromolecules. The formation of PAH-DNA adducts (DNA binding products), considered a necessary step in PAH-initiated carcinogenesis, has been widely studied in experimental models and has been documented in human tissues. This review describes immunohistochemistry (IHC) studies, which reveal localization of PAH-DNA adducts in human tissues, and semi-quantify PAH-DNA adduct levels using the Automated Cellular Imaging System (ACIS). These studies have shown that PAH-DNA adducts concentrate in: basal and supra-basal epithelium of the esophagus, cervix and vulva; glandular epithelium of the prostate; and cytotrophoblast cells and syncitiotrophoblast knots of the placenta. The IHC photomicrographs reveal the ubiquitous nature of PAH-DNA adduct formation in human tissues as well as PAH-DNA adduct accumulation in specific, vulnerable, cell types. This semi-quantative method for PAH-DNA adduct measurement could potentially see widespread use in molecular epidemiology studies. PMID:21845152

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



Interspecies and spatial trends in polycyclic aromatic hydrocarbons (PAHs) in Atlantic and Mediterranean pelagic seabirds.  


PAHs were analyzed in the liver of 5 species of pelagic seabirds (Procellariiformes) from the northeast Atlantic and the Mediterranean. The main objective was to assess the trophic and geographic trends of PAHs in seabirds to evaluate their suitability as bioindicators of chronic marine pollution by these compounds. Although higher levels of PAHs have been described in the Mediterranean compared to other oceanic regions, we did not find significant spatial patterns and observed only minor effects of the geographic origin on seabird PAHs. However, we found significant higher PAH levels in petrel compared to shearwater species, which could be related to differences in their exploitation of mesopelagic and epipelagic resources, respectively, and the vertical dynamic of PAHs in the water column. Overall, although this study enhances the need of multi-species approaches to show a more comprehensive evaluation of marine pollution, seabirds emerged as poor indicators of pelagic chronic PAH levels. PMID:21620541

Roscales, Jose L; González-Solís, Jacob; Calabuig, Pascual; Jiménez, Begoña



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

USGS Publications Warehouse

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 (?PAH8) 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 ?g m-2 h-1 and decreased rapidly during the 45 days after application to 160 ?g m-2 h-1. Loss of PAHs from the adhered sealant also was rapid, with about a 50% decrease in solid-phase ?PAH8 concentration over the 45 days after application. There was general agreement, given the uncertainties, in the estimated mass of ?PAH8 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 ?PAH8 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.

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



Urinary polycyclic aromatic hydrocarbons as a biomarker of exposure to PAHs in air: A pilot study among pregnant women  

Microsoft Academic Search

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”

Elizabeth Nethery; Amanda J Wheeler; Mandy Fisher; Andreas Sjödin; Zheng Li; Lovisa C Romanoff; Warren Foster; Tye E Arbuckle



Uptake of (/sup 3/H)PAH and (/sup 14/C)urate into isolated proximal tubular segments of the pig kidney  

SciTech Connect

Segments of proximal convoluted (PCT) and proximal straight (PST) tubules of minipigs and normal-sized pigs were microdissected (without collagenase treatment) and incubated (30 min, 37/sup 0/C, pH 7.4) in Ringer solution (under O/sub 2/) containing (/sup 3/H)PAH (3.10/sup -5/ M) or (/sup 14/C)urate (9.10/sup -5/ M) and, in inhibitor studies, probenecid, pyrazinoic acid (PZA), urate, or PAH, all at 1 mM. In both strains the uptake of (/sup 3/H)PAH expressed as mean T/M ratio (cpm per ml tissue water/cpm per ml incubation medium) was significantly higher (P<0.001) in PCT than in PST. T/M was 34.7 +/- 5.6 (SE) in 34 PCT and 2.4 +/- 0.3 in 24 PST of eight minipigs. In two normal-sized pigs the T/M was 14.1 +/- 3.6 in 15 PCT and 1.5 +/- 0.1 in six PST. Similar results were obtained for (/sup 14/C)urate. In eight minipigs the T/M was 4.9 +/- 0.5 in 24 PCT and 2 +/- 0.2 in 25 PST. In normal-sized pigs the T/M was 3.8 +/- 0.3 in 35 PCT (five pigs) and 1.9 +/- 0.4 in eight PST (two pigs). In inhibitor studies urate significantly depressed the uptake of (/sup 3/H)PAH, and unlabeled PAH depressed the uptake of (/sup 14/C)urate. PZA significantly inhibited the uptake of (/sup 14/C)urate but not that of (/sup 3/H)PAH, whereas probenecid had a strong inhibitory efect on the uptake of both compounds. These results suggest that (/sup 14/C)urate and (/sup 3/H)PAH are transported by a transport system located mainly in the proximal convoluted tubule. These findings are in contrast in the findings are in contrast to the findings obtained in rabbits in which the transport system of PAH and urate is mainly located in the proximal part of the pars recta.

Schali, C.; Roch-Ramel, F.



Paper Diagnostics  

NSDL National Science Digital Library

This lesson, presented by the National Nanotechnology Infrastructure Network, focuses on diagnostic methods of investigation looking at the issue of HIV/AIDS. In this activity, students will explore "the societal impacts of engineering and science, specifically as it relates to the AIDS epidemic in developing countries. A series of videos and accompanying questions help students explore how engineers and scientists can contribute to various solutions related to diagnosing and preventing the spread of disease. The activity highlights the development of low-cost paper diagnostics for rapid and private diagnosis of AIDS and diseases  related to AIDS (TB, other sexually transmitted diseases, etc.)." This activity will take two 50 minute classroom sessions. A Teacher Preparation Guide, Next Generation Science Standards for this lesson, and a link to George Whitesides video used in lesson video from the NY Times are included.


Cells on fibers to degrade PAH and upgrade coal  

SciTech Connect

There are over 2000 sites contaminated with PAH`s from coal burning plants. White rot fungus degrades phenanthrene and anthracene, but the fungus needs air to grow. When grown on old cardboard boxes and buried, air is entrapped in the corrugations for growth of the fungus. When holes are put in the valleys of the corrugations and rotated in a half full reactor, drops are formed. Mass transfer to drops is much faster than to a flat surface, as described in Patent 5,256,570, so the fungus grows faster. Low rank coal can be upgraded to more valuable products with the fungus, say some Australians, but the problem is supplying oxygen. Celite can be entrapped in the fibers to ferment coal derived synthesis gas. The paper describes these processes.

Clyde, R.



NSTX Diagnostics and Operation: Status and Plans  

SciTech Connect

The low aspect ratio and low magnetic field of the National Spherical Torus Experiment (NSTX) create many challenges for plasma diagnostics and control, as well as opportunities for studying new plasma phenomena. This paper describes the diagnostics now installed for studies of confinement, stability and edge plasma phenomena, and some of the diagnostic developments planned for the near future. The design of the plasma control system and plans for its development are also presented.

M.G. Bell; R.E. Bell; B.P. LeBlanc; S.S. Medley; and the NSTX Research Team



Concentrations of heavy metals (Cu, Cd, Zn and Ni) and PAHs in Perna viridis collected from seaport and non-seaport waters in the Straits of Johore.  


In this study, the ranges of pollutants found in the soft tissues of Perna viridis collected from Kg. Masai and Kg. Sg. Melayu, both located in the Straits of Johore, were 0.85-1.58 ?g/g dry weight (dw) for Cd, 5.52-12.2 ?g/g dw for Cu, 5.66-8.93 ?g/g dw for Ni and 63.4-72.3 ?g/g dw for Zn, and 36.4-244 ng/g dry weight for ?PAHs. Significantly (p < 0.05) higher concentrations of Cd, Cu, Ni, Zn and ?PAHs in the mussels were found in the water of a seaport site at Kg. Masai than a non-seaport site at Kg. Sg. Melayu population. The ratios of low molecular weight/high molecular weight hydrocarbons (2.94-3.42) and fluoranthene/pyrene (0.43-0.45) in mussels from both sites indicated the origin of the PAHs to be mainly petrogenic. This study has demonstrated the utility of using the soft tissues of P. viridis as a biomonitor of PAH contamination and bioavailability in the coastal waters of Peninsular Malaysia. PMID:23052577

Yap, C K; Shahbazi, A; Zakaria, M P



Polynuclear aromatic hydrocarbons (PAHs) differentially influence growth of various emergent wetland species.  


The growth of emergent wetland plants may be influenced by toxic organic pollutants, which would influence the extent of phytoremediation when used in constructed wetlands. A series of glasshouse experiments were conducted to investigate the influence of polynuclear aromatic hydrocarbons (PAHs) on the growth of various emergent wetland species. The response of species to PAHs varied significantly. A significant interaction (species x PAH treatment) was observed for relative growth rates (RGRs) of Baumea juncea, Baumea articulata, Schoenoplectus validus and Juncus subsecundus in hydroponics with naphthalene, and of B. juncea and J. subsecundus in soils freshly spiked with phenanthrene and pyrene. In hydroponics, biomass of B. articulata significantly increased in the treatments with relatively low addition of naphthalene, whereas that of S. validus significantly increased with all naphthalene additions. In both hydroponics and soils, the growth of B. juncea increased with the PAH (phenanthrene and pyrene) additions, whereas that of J. subsecundus decreased in the treatments with relatively high concentrations of PAHs. The removal of PAHs from soil was not affected significantly by J. subsecundus after 70 days of growth and B. juncea after 150 days of growth. The growth of J. subsecundus was slightly (but not significantly) influenced by the PAH residues in soil. The effect of PAHs on wetland plant growth could be species-specific regardless of PAH types and media. The response of species to PAHs needs to be taken into account when selecting species for wetlands constructed for phytoremediation. PMID:20633994

Zhang, Zhenhua; Rengel, Zed; Meney, Kathy



Genotoxicity of oxy-PAHs to Japanese medaka (Oryzias latipes) embryos assessed using the comet assay.  


Polycyclic aromatic hydrocarbons (PAHs) have long been recognized as important environmental toxicants. Despite a plethora of information on the fate and effects of parent PAHs, relatively little is known about the environmental fate and toxicity of ketone- and quinone-substituted PAH oxidation products (termed oxy-PAHs), particularly in the aquatic environment. This study begins to fill that gap using embryos of the Japanese medaka (Oryzias latipes) as a model species. The genotoxic potential of two environmentally relevant oxy-PAHs, acenaphthenequinone and 7,12-benz[a]anthracenquinone, was assessed using the comet assay. We found that both oxy-PAHs could cause significant increases in DNA damage after only 48 h of exposure at the lowest concentrations tested (5 ?g/L). Comparisons of the genotoxic potential between these oxy-PAHs and their corresponding parent PAHs (acenaphthene and benz[a]anthracene) and a well-known mutagenic PAH, benzo[a]pyrene, indicated similar potencies among all five of these compounds, particularly after longer (7 day) exposures. This study demonstrates the mutagenic potential of oxy-PAHs to an in vivo fish embryo model and points out the need for further study of their environmental occurrence and biologic effects. PMID:24510601

Dasgupta, Subham; Cao, Austin; Mauer, Brittany; Yan, Beizhan; Uno, Seiichi; McElroy, Anne



Biodiesel emissions profile in modern diesel vehicles. Part 2: Effect of biodiesel origin on carbonyl, PAH, nitro-PAH and oxy-PAH emissions.  


In the present study, the effects of different biodiesel blends on the unregulated emissions of a Euro 4 compliant passenger car were examined. Two fresh and two oxidized biodiesel fuels of different source materials were blended with an ultra low sulphur automotive diesel fuel at proportions of 10, 20, and 30% v/v. Emission measurements were conducted on a chassis dynamometer with a constant volume sampling (CVS) technique, over the New European Driving Cycle (NEDC) and the Artemis driving cycles. The experimental results revealed that the addition of biodiesel led to important increases in most carbonyl compounds. Sharp increases were observed with the use of the oxidized biodiesel blends, especially those prepared from used frying oil methyl esters. Similar to carbonyl emissions, most PAH compounds increased with the addition of the oxidized biodiesel blends. It can be assumed that the presence of polymerization products and cyclic acids, along with the degree of unsaturation were the main factors that influenced carbonyl and PAH emissions profile. PMID:21122895

Karavalakis, Georgios; Boutsika, Vasiliki; Stournas, Stamoulis; Bakeas, Evangelos



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

SciTech Connect

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) 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 between total PCDD/Fs and total PAHs, although no such relationship has been found for TEQ.

Chen, Ying, E-mail: [School of Environment, Tsinghua University, Beijing 100084 (China); National Center of Solid Waste Management, Ministry of Environmental Protection, Beijing 100029 (China); Zhao, Rongzhi [Civil and Environmental Engineering School, University of Science and Technology Beijing, Beijing 100083 (China); Xue, Jun [National Center of Solid Waste Management, Ministry of Environmental Protection, Beijing 100029 (China); Li, Jinhui, E-mail: [State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084 (China)



Impact of reclaimed water irrigation on PAHs in agricultural soil and groundwater  

NASA Astrophysics Data System (ADS)

Reclaimed water is becoming one of the most important water resources for irrigation, especially in arid and semi-arid areas. However, whether the organic compounds will pollute the soil and groundwater or not under the condition of long-term irrigation, has become a matter of great concern. Soil samples of 3 boreholes at the depths of 0-5.5 m and groundwater samples were collected from the reclaimed water irrigation area of Beijing Southeast suburb. 16 EPA priority polycyclic aromatic hydrocarbons (PAHs) were analyzed using gas chromatography and mass spectrometry (GC-MS). The results showed that the total amount of 16 PAHs at whole profile varied from 12.44-206.75 ?g?kg-1 (dry wt). The highest total contents of PAHs appeared in the surface layer, and they declined dramatically along the soil profiles. In the topsoil, high weight molecular PAHs (>4 rings) were the main pollutants which were accounting for 70% of the total PAHs. Under the surface layer, Naphthalene, Fluorene, Phenanthrene, Fluoranthene and Pyrene were the main detected PAHs. The PAHs contents ranked as follows: 2 rings>3 rings>4 rings. The total PAHs concentrations in groundwater ranged from 17.62-27.09 ng?L-1, 179.41-959.77 ng?L-1 and 52.46-1069.52 ng?L-1 in spring, summer and winter, respectively. The detected PAHs in the groundwater were 2 and 3 rings PAHs, which were consistent with those of the soil profiles. It supposed that reclaimed water was the main source of PAHs. Meanwhile, Naphthalene and Phenanthrene were still the most abundant individual PAHs in groundwater, indicating that long-term reclaimed water irrigation can lead to the vertical migration of low weight molecular PAHs (2-3 rings).

Jin, Aifang; He, Jiangtao; Chen, Sunuan; Huang, Guoxin



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


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. PMID:23089061

Rauscher, Lindy; Sakulthaew, Chainarong; Comfort, Steve



Diagnostically lossless compression of medical images-2  

Microsoft Academic Search

A method is proposed which provides high compression ratios for radiographic images with no loss of diagnostic quality. Two approaches are discussed, In medical images, only a small region is diagnostically relevant, while the remaining regions are much less important, the first approach is to compress the important region strictly losslessly, and to compress the remaining regions of the image

Robina Ashraf; Muhammad Akbar



Influence of biotransformation on trophic transfer of the PAH, fluoranthene.  


The persistence of polycyclic aromatic hydrocarbons (PAHs) in marine sediments may be influenced by benthic invertebrate bioturbation. Through processes such as deposit-feeding and enhancement of microbial metabolic activity PAHs may be remobilized from the sediment compartment, and either transferred to organisms at higher trophic levels or to the overlying water column, both processes inevitably changing the bioavailability of the PAH. Accumulation of contaminants from one level in the food chain to the next depends on feeding rate and assimilation efficiency, two factors that basically vary with food quality and contaminant type. Though it is generally believed that pre-consumptive biotransformation will reduce bioavailability due to the more polar nature of the metabolites compared to the unchanged parent compound, theoretically the decrease in lipophilicity will increase the sediment/food desorption rate in the intestine, and some metabolites will still be lipophilic enough to be absorbed by passive diffusion. We examined the trophic transfer of the PAH, fluoranthene from two closely related polychaete species (i.e., Capitella sp. I and Capitella sp. S), differing in their biotransformation ability, to the predatory polychaete, Nereis virens. We found that N. virens fed the biotransforming species, Capitella sp. I, accumulated significantly more Flu equivalents compared to worms fed Capitella sp. S, which have a very limited biotransformation ability. The dose-specific increase in N. virens intestinal Flu concentration was approximately twice as high in worms fed Capitella sp. I (equation: gut content=7.3 x dose-3.9) compared to worms fed Capitella sp. S (equation: gut content=3.2 x dose+0.6). In addition, we measured DNA damage, using the comet assay, in N. virens intestinal cells after feeding with the two prey species. We did not detect DNA damage above 'background' levels for worms fed either of the two Capitella species, possibly due to relatively low intestinal Flu concentrations in N. virens. Our results indicate that accumulation of PAHs by infaunal organisms may play an important role in the transfer of this type of contaminant to higher trophic levels. Moreover, we observed differences in transfer potential between parent compounds and their respective metabolites, which may influence the fate of these compounds in marine ecosystems. However, from the present study it cannot be concluded whether differences in biotransformation ability among prey species can lead to different effects in their predators. PMID:17084915

Palmqvist, Annemette; Rasmussen, Lene Juel; Forbes, Valery E



Special Diagnostics  

NASA Technical Reports Server (NTRS)

This section contains a number of special diagnostics that are designed to examine certain mechanisms. Section 1 reports on the method used to test the photochemical partitioning in the models. Sections 2 and 3 represent efforts to examine the model calculated production and removal rates for ozone and how the values are combined with transport rates in the models to produce the simulated ozone distributions. Sections 4 and 5 concentrate on polar processes including the dynamics aspect of vortex confinement and the chemical aspects of chlorine activation.

Ko, Malcolm K. W.; Salawitch, Ross J.; Jackman, Charles H.; Considine, David B.; Douglass, Anne R.



PAH Concentrations Decline Following 2006 Ban on Coal-Tar-Based Pavement Sealants in Austin, Texas  

NASA Astrophysics Data System (ADS)

Recent studies have concluded that coal-tar-based pavement sealants (CT sealants) are a major source of polycyclic aromatic hydrocarbons (PAHs) in non-industrial urban settings in the United States. In 2006, Austin, TX, became the first jurisdiction in the U.S. to ban the use of CT sealants. We evaluated PAH concentrations following the ban by analyzing sediment cores collected from Lady Bird Lake in 2012; Lady Bird Lake impounds the Colorado River in central Austin and receives runoff from much of the greater Austin area. The mean sum concentration of the 16 U.S. Environmental Protection Agency Priority Pollutant PAHs (?PAH16) in one of two 2012 sediment cores analyzed for PAHs declined 75% from before 2006 (mean of 4 samples=8,090 ?g kg-1) to 2012 (mean of 2 samples=2,030 ?g kg-1), reversing a 40-year (1959-1999) upward trend in PAH concentrations that was previously documented. The downward trend in PAH concentrations in the seven uppermost 1 cm sampling intervals in the first 2012 core was statistically significant (r=0.93, p-value=0.002). Post-2008 PAH trends in the second 2012 core were similar (significant downward trend in the six uppermost 1 cm sampling intervals and mean 2012 ?PAH16 of 2,390 ?g kg-1); however, pre-2007 sediment did not appear to have been preserved in this core likely because of the effects of flooding on sediment deposition and mixing at this site--the largest flood on the Colorado River in Austin in 20 years was in 2007. On the basis of a comparison of lake-sediment PAH profiles to 22 PAH source profiles, the PAH loading to lake sediment continues to be dominated by CT sealants. The continued dominance of proportional PAH loading by CT sealants in spite of decreased concentrations since 2006 might be because legacy CT sealant and contaminated soils and sediments continue to yield PAHs to runoff. A previous study using source-receptor modeling concluded that CT sealants were the largest PAH source to 40 urban lakes studied in the U.S. (including Lady Bird Lake) and were the primary cause of increasing PAH trends in recent decades. The results presented here are the first direct evidence that removing this source can lead to a substantial reduction in PAH concentrations in receiving water bodies. CT sealants are sprayed or painted on asphalt parking lots and driveways. The sealant abrades into fine particles that can be washed into streams and lakes and tracked into homes.

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



Laboratory and Ambient Studies of the Products of Gas-Phase Hydroxyl and Nitrate Ion Radical-Initiated Reactions with Selected PAHs  

NASA Astrophysics Data System (ADS)

Nitrated polycyclic aromatic hydrocarbon (nitro-PAH) product distributions from the gas-phase hydroxyl (OH) and nitrate (NO3) radical-initiated reactions with selected PAHs, as well as the heterogeneous reactions of surface-bound PAHs with N2O5 and HNO3, were investigated. Chapter 2 presents formation yields of nitro-PAHs from the gas-phase OH radical-initiated reactions of 1,7- and 2,7-dimethylnaphthalene (DMN) as a function of NO 2 concentration over the range 0.04-0.14 ppmv. The measured formation yields of dimethylnitronaphthalenes (DMNNs) under conditions that the OH-DMN adducts reacted solely with NO2 were 0.252 ± 0.094% for ?1,7-DMNNs and 0.010 ± 0.005% for ?2,7-DMNNs. 1,7-dimethyl-5-nitronaphthalene (1,7DM5NN) was the major nitro-isomer formed, with a limiting high-NO 2 concentration yield of 0.212 ± 0.080% and with equal reactions of the 1,7-DMN-OH adduct with NO2 and O2 occurring in air at 60 ± 39 ppbv of NO2, indicating that the OH-DMN adduct reaction with NO2 can be important at NO2 concentrations commonly found in urban atmospheres. Although the yields of the DMNNs are low, ?0.3%, the DMNN (and ethylnitronaphthalene) profiles from chamber experiments match well with those observed in polluted urban areas under conditions where OH radical-initiated chemistry is dominant, such as Mexico City, Mexico. Chapter 3 examines the nitro-PAH products of gas-phase OH and NO 3 radicals and heterogeneous N2O5 reactions with fluoranthene, pyrene, benz[a]anthracene, chrysene, and triphenylene. Analysis of nitro-PAHs in the NIST diesel particulate SRM (1975) and selected ambient samples are also presented. 2-Nitrofluoranthene (2-NFL) was the most abundant nitro-PAH in Riverside, CA and Mexico City, and the mw 273 nitro-PAHs were observed in lower concentrations. However, in Tokyo, Japan, concentrations of 1- + 2-nitrotriphenylene (NTP) were more similar to those of 2-NFL. Comparing specific nitro-PAH ratios in ambient particulate samples from Tokyo, Mexico City, and Riverside, and in diesel particles with those from chamber experiments confirms the atmospheric formation of 2-NFL and 2-nitropyrene (2-NPY) via gas-phase radical-initiated reactions. Heterogeneous nitration of ambient particle-bound PAHs is investigated in Chapter 4. Ambient particulate samples collected in Beijing, China, and from four sites within the Los Angeles air basin (Los Angeles, Azusa, Riverside, and Banning), along with filter-bound deuterated PAHs, were exposed to a gas-phase equilibrium mixture of N2O5, NO3 radicals, and NO2 in an environmental chamber at ambient pressure and temperature. For the majority of these reactions 1-nitropyrene was the nitro-PAH formed in the greatest amount and was determined to occur heterogeneously (and not in the gas-phase) by using isomer distribution patterns of deuterated nitro-PAHs either formed on filter surfaces or collected from the chamber in the gas-phase. Chapter 5 investigates the contributions of atmospheric formation (OH versus NO3 chemistry) and direct emissions (electrophilic nitration products) to ambient gas-phase and particulate nitro-PAHs sampled in the Los Angeles air basin and Mexico City, Mexico, over several sampling campaigns using a combination of several marker ratios of volatile and semi-volatile nitro-PAHs. Ratios of 2-nitrofluoranthene (2-NFL)/2-nitropyrene (2-NPY), 2-methyl-4-nitronaphthalene (2M4NN)/1-methyl-5-nitronaphthalene (1M5NN), and 2,7-dimethyl-4-nitronaphthalene (2,7DM4NN)/1,7-dimethyl-5-nitronaphthalene (1,7DM5NN) were used to assess the contribution of OH radical chemistry versus NO3 radical chemistry to ambient nitro-PAHs from 50 particle-phase and gas-phase samples. (Abstract shortened by UMI.).

Zimmermann, Kathryn Jean


AKARI infrared camera observations of the 3.3 ?m PAH feature in Swift/BAT AGNs  

NASA Astrophysics Data System (ADS)

We explore the relationships between the 3.3 ?m polycyclic aromatic hydrocarbon (PAH) feature and active galactic nucleus (AGN) properties of a sample of 54 hard X-ray selected bright AGNs, including both Seyfert 1 and Seyfert 2 type objects, using the InfraRed Camera (IRC) on board the infrared astronomical satellite AKARI. The sample is selected from the nine-month Swift/BAT survey in the 14-195 keV band and all of them have measured X-ray spectra at E ? 10 keV. These X-ray spectra provide measurements of the neutral hydrogen column density (NH) towards the AGNs. We use the 3.3 ?m PAH luminosity (L3.3?m) as a proxy for star-formation activity and hard X-ray luminosity (L14-195 keV) as an indicator of the AGN activity. We search for possible differences in star-formation activity between type 1 (unabsorbed) and type 2 (absorbed) AGNs. We have made several statistical analyses taking the upper limits of the PAH lines into account utilizing survival analysis methods. The results of our log (L14-195 keV) versus log (L3.3 ?m) regression show a positive correlation and the slope for the type 1/unobscured AGNs is steeper than that of type 2/obscured AGNs at a 3 ? level. Our analysis also shows that the circumnuclear star formation is more enhanced in type 2/absorbed AGNs than type 1/unabsorbed AGNs for low X-ray luminosity/low Eddington ratio AGNs, while there is no significant dependence of star-formation activities on the AGN type in the high X-ray luminosities/Eddington ratios.

Castro, Angel; Miyaji, Takamitsu; Shirahata, Mai; Ichikawa, Kohei; Oyabu, Shinki; Clark, David M.; Imanishi, Masatoshi; Nakagawa, Takao; Ueda, Yoshihiro



Sorption of polycyclic aromatic hydrocarbons (PAHs) to lignin: effects of hydrophobicity and temperature.  


The study of the sorption of contaminants to lignin is significant for understanding the migration of contaminants in the environment as well as developing low cost sorbent. In this study, sorption of three polycyclic aromatic hydrocarbons (PAHs), naphthalene, acenaphthene and phenanthrene, to lignin was investigated. Sorption isotherms were well described by both linear and Freundlich sorption models. Sorption coefficients of PAHs to lignin from water obtained from regression of both linear model (K d) and Freundlich model (K f) were highly positively correlated with hydrophobicity of PAHs. The amorphous structure of lignin provided sufficient sorption domain for partitioning of PAHs, and the attraction between PAHs molecules and aromatic fractions in lignin via ?-? electron-donor-acceptor (?-? EDA) interaction is hypothesized to provide a strong sorption force. Thermodynamic modeling revealed that sorption of PAHs to lignin was a spontaneous and exothermic process. PMID:24838935

Zhang, Ming; Ahmad, Mahtab; Lee, Sang Soo; Xu, Li Heng; Ok, Yong Sik



Extraction agents for the removal of polycyclic aromatic hydrocarbons (PAHs) from soil in soil washing technologies.  


Polycyclic aromatic hydrocarbons (PAHs) in soil have been recognised as a serious health and environmental issue due to their carcinogenic, mutagenic and teratogenic properties. One of the commonly employed soil remediation techniques to clean up such contamination is soil washing or solvent extraction. The main factor which governs the efficiency of this process is the solubility of PAHs in the extraction agent. Past field-scale soil washing treatments for PAH-contaminated soil have mainly employed organic solvents or water which is either toxic and costly or inefficient in removing higher molecular weight PAHs. Thus, the present article aims to provide a review and discussion of the alternative extraction agents that have been studied, including surfactants, biosurfactants, microemulsions, natural surfactants, cyclodextrins, vegetable oil and solution with solid phase particles. These extraction agents have been found to remove PAHs from soil at percentages ranging from 47 to 100% for various PAHs. PMID:24100092

Lau, Ee Von; Gan, Suyin; Ng, Hoon Kiat; Poh, Phaik Eong



Study of PAH emission from the solid fuels combustion in residential furnaces.  


The procedure for and results of a test study of polycyclic aromatic hydrocarbon (PAH) emission from a few types of solid fuels combustion in residential furnaces of various designs typical for Belarus are discussed. Greatest levels of PAH emission were detected from domestic wastes and wood waste combustion. Lowest levels of PAH emission are from peat briquette combustion. It was found that PAH concentration in off-gases from firewood combustion also varies significantly depending on the type of wood: the highest values of PAH are typical for waste gases from birch firewood combustion in comparison with pine firewood combustion. Draft PAH emission factors are proposed with intended application for emission inventory of such installations. PMID:15519469

Kakareka, Sergey V; Kukharchyk, Tamara I; Khomich, Valery S



Impact of soil amendments and the plant rhizosphere on PAH behaviour in soil.  


Carbonaceous amendments reduce PAH dissolved concentrations (Cfree), limiting their uptake and toxicity. A soil contaminated with PAHs was mixed with activated carbon (AC), charcoal or compost and planted with radish (Raphanus sativus L.), and Cfree, chemical activities and diffusive uptake of the PAHs measured over 2 months. For AC, Cfree and diffusive uptake were decreased by up to 94% compared to the unamended soil within one week. In addition, the sum chemical activity of the PAHs remained below the threshold for baseline toxicity. In contrast, charcoal and compost only led to modest reductions in Cfree and diffusive uptake, with sum chemical activities that could potentially result in baseline toxicity being observed. Furthermore, both Cfree and diffusive uptake were lower in the planted compared to unplanted soils. Therefore, only AC successfully reduced PAH acute toxicity in the soil, but plant-promoted microbial degradation may also play an important role in PAH attenuation. PMID:24583710

Marchal, Geoffrey; Smith, Kilian E C; Mayer, Philipp; Wollesen de Jonge, Lis; Karlson, Ulrich G



Genomic structure of the Aeromonas bacteriophage pAh6-C and its comparative genomic analysis.  


pAh6-C is a virulent bacteriophage (phage), isolated from a river in Korea, that infects a multiple-antibiotic-resistant A. hydrophila strain, JUNAH. The double-stranded DNA genome of pAh6-C is composed of 53,744 bp with a G + C content of 52.83 %. The genome encodes 86 putative ORFs, four putative promoters, and seven transcriptional terminator regions. Genome sequence analysis of pAh6-C and comparative analysis with the homologous Shewanella phage Spp001 revealed that there is a high degree of similarity between pAh6-C and Spp001 in 50 of the 86 ORFs of pAh6-C. The results of this investigation indicate that pAh6-C is closely related to Spp001, especially in the genes coding for proteins involved in DNA metabolism. PMID:25189428

Jun, Jin Woo; Kim, Hyoun Joong; Yun, Sae Kil; Chai, Ji Young; Park, Se Chang



Distribution and transport of PAHs in soil profiles of different water irrigation areas in Beijing, China.  


Vertical distribution characteristics and transport mechanisms of polycyclic aromatic hydrocarbons (PAHs) in soil profiles (0-5.5 m) of different water irrigation areas in the southeast suburb of Beijing were analyzed and compared. 16 priority PAHs on the United States Environmental Protection Agency (US EPA) list were analyzed using gas chromatography and mass spectrometry (GC-MS). The relationship between the properties of soil and PAHs was also studied by statistical analyses. The results showed that total PAH concentrations in the topsoils of the wastewater irrigation (WWI) area, reclaimed water irrigation (RWI) area, groundwater irrigation (GWI) area were much higher than those in the deep soils, with the concentrations of 726.0, 206.8 and 42.8 ?g kg(-1) (dry wt), respectively. The low molecular weight (LMW) PAHs (2-3 ring) including naphthalene (Nap), phenanthrene (Phe), fluorene (Fl) dominated the layers (0.5-5.5 m) underneath the surfaces. The migration of LMW PAHs was faster than that of high molecular weight (HMW) PAHs and LMW PAHs were transported in dissolved matter. The different soil textures of three sites caused the differences in the variation ranges of PAHs in the profiles. The statistical analyses showed a significant linear positive correlation between PAHs and total organic carbon (TOC). The 2-4 ring PAHs were detected in the wastewater and reclaimed waters, which was consistent with those in the soil profiles. The presence of PAHs in the soil profiles was mainly due to the irrigation of wastewater. Wastewater reuse guidelines and standards for irrigation should be established urgently. PMID:24781137

Jin, Aifang; He, Jiangtao; Chen, Sunuan; Huang, Guoxin



Enhancing the release and plant uptake of PAHs with a water-soluble purine alkaloid  

Microsoft Academic Search

The effect of a common plant alkaloid, caffeine, on the release and plant uptake of some polycyclic aromatic hydrocarbons (PAHs) in soils was investigated. Cucurbita pepo (ssp. pepo cv. Gold Rush) was grown in PAH-spiked media in the presence and absence of caffeine. Solubility tests initially confirmed the ability of caffeine to dissolve PAHs mixtures of anthracene, phenanthrene, pyrene, benzo[a]pyrene

Ronald R. Navarro; Hiroyasu Ichikawa; Kengo Morimoto; Kenji Tatsumi



Polycyclic aromatic hydrocarbons (PAHs) in surface waters of Ráckevei-Soroksári Danube Branch, Hungary.  


Concentrations of polycyclic aromatic hydrocarbons (PAHs) in the surface waters of Ráckevei-Soroksári Danube (RSD) branch, Hungary were determined at ten sites during eight sampling events from October 2002-April 2004. Low and medium molecular weight PAHs (2-4 rings) varied from a few ng/L to hundreds of ng/L while high molecular weight PAHs (5-6 rings) were present at much lower concentrations (< 0.5-31 ng/L). Generally, concentrations of most of the individual PAHs were not significantly different (p > 0.05) during the different seasons. Concentrations of anthracene, fluoranthene, and pyrene were significantly lower (p < 0.005) in the winter month whereas concentrations of benzo(a) anthracene, chrysne, and benzo(b)fluoranthene were significantly lower (p < 0.05) in the fall season. Possible causes of such distribution in the surface waters of RSD include nature of the inputs of organic matter and different systems of winds or rains of the seasons. Of the total PAHs, the 2-3-ring PAHs contributed to about 78% while 4-6-ring PAHs accounted for 22%. This suggests that the incomplete combustion of fossil hydrocarbons may be the predominate source of PAHs in surface water of RSD. Seasonally, petroleum and heavy fuel combustion were main sources of PAHs in summer and winter seasons, respectively. However, both sources contribute to PAHs in the spring season. The levels of PAHs in our study were compared with other regions of the world. Concentrations of PAHs in our study were higher than most of the surface waters of Europe, North America, and Australia, but similar to some parts of European and Asian regions. PMID:17365289

Nagy, Peter; Fekete, Jeno; Sharma, Virender K



Atmospheric concentrations and dry deposition rates of polycyclic aromatic hydrocarbons (PAHs) for Tampa Bay, Florida, USA  

Microsoft Academic Search

Sampling of 16 USEPA priority polycyclic aromatic hydrocarbons (PAHs) at the Gandy Bridge monitoring site between May and August 2002 provided preliminary ambient air concentrations and dry deposition rates for Tampa Bay. The HiC-IOGAPS dramatically improved the recovery of lower molecular weight gas and particle PAHs, as evidenced by the recoveries of PAHs in back-up denuders and filter packs. Total

Noreen Poor; Raphael Tremblay; Heidi Kay; Venkat Bhethanabotla; Erick Swartz; Mark Luther; Scott Campbell



Distribution of polycyclic aromatic hydrocarbons (PAHs) in floodplain soils of the Mosel and Saar River  

Microsoft Academic Search

Background, Aim and Scope  Polycyclic aromatic hydrocarbons (PAHs) have gained serious attention in the scientific community due to their persistence\\u000a and toxic potential in the environment. PAHs may pose a risk to ecosystem health. Along the Mosel River\\/Germany, a tributary\\u000a of the river Rhine, PAHs were found at significantly high concentrations (> 20 mg kg?1, German national guideline value Z2, LAGA

Carmen Pies; Yi Yang; Thilo Hofmann



PAH source fingerprints for coke ovens, diesel and, gasoline engines, highway tunnels, and wood combustion emissions  

Microsoft Academic Search

To evaluate the chemical composition (source fingerprint) of the major sources of polyaromatic hydrocarbons (PAHs) in the Chicago metropolitan area, a study of major PAH sources was conducted during 1990–1992. In this study, a modified high-volume sampling method (PS-1 sampler) was employed to collect airborne PAHs in both the particulate and gas phases. Hewlett Packard 5890 gas chromatographs equipped with

Nasrin R. Khalili; Peter A. Scheff; Thomas M. Holsen



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


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 41mgkg(-1) in 120 days. This concentration is below the threshold level required for Chinese soil PAH quality (45mgkg(-1) dry weight) for residential use. PMID:25534968

Lu, Yan-Fei; Lu, Mang



Polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides in water columns from the Pearl River and the Macao harbor in the Pearl River Delta in South China.  


Polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) were measured in suspended particles and dissolved phase from the Baiertang water column and the Macao water column samples as collected from the Guangzhou channel of the Pearl River and the Macao harbor, where the sediments were heavily contaminated with organic pollutants. Total OCPs concentration varies from 23.4 to 61.7 ng/l in Baiertang water column and from 25.2 to 67.8 ng/l in Macao column, while total PAHs concentration varies from 987.1 to 2878.5 ng/l in the Baiertang water column and from 944.0 to 6654.6 ng/l in the Macao column. The vertical distribution profiles of pollutants and the partition of pollutants between particles and dissolved phases indicate that the sediments in Baiertang act as an important source of selected pollutants, and the pollutants in water of this region were mainly originated from the release and re-suspension of contaminants residing in the sediments. The sediments in Macao harbor act as a reservoir for organochlorine pesticides, such as DDTs mainly introduced by river inflow from Xijiang and PAHs input by brackish water from the Lingdingyang estuary. Combustion of fossil fuels and petroleum input are the main sources of PAHs in the Macao water column, while combustion of fossil fuels and coal is responsible for the PAHs in the Baiertang water column. The ratios of DDT/(DDD+DDE) for the Macao water column samples demonstrate that such chemicals were input into this region in recent times. PMID:15172816

Luo, Xiaojun; Mai, Bixian; Yang, Qingshu; Fu, Jiamo; Sheng, Guoying; Wang, Zhishi



Semipermeable membrane devices accumulate conserved ratios of sterane and hopane petroleum biomarkers.  


Semipermeable membrane devices (SPMDs) are commonly used as a time-integrated measure of aqueous concentrations of persistent hydrophobic chemicals, including PAH, pesticides, dioxins, and PCBs. Another class of persistent hydrophobic chemicals is petroleum biomarker compounds (hopanes and steranes) that are used for hydrocarbon source identification and allocation. In this study three different passive sampling device designs were exposed to a complex hydrocarbon mixture (Alaska North Slope crude) in a laboratory experiment to determine uptake rates of biomarkers into SPMDs. In addition to the standard triolein filled SPMDs, iso-octane filled SPMDs (ISPMDs) and unfilled low-density polyethylene strips (PESDs) were tested. Uptake rates and effective sampling rates were determined for 53 compounds. There was little variation in sampling rates among the individual biomarkers; average values (ld(-1)) for hopanes were 0.43+/-0.07 (PESD), 0.33+/-0.06 (SPMD), and 0.44+/-0.03 (ISPMD) and average sterane sampling rates were 0.57+/-0.04 (PESD), 0.42+/-0.03 (SPMD), and 0.53+/-0.03 (ISPMD). The primary reason for biomarker analysis is for source discrimination of petroleum. Nineteen different diagnostic ratios were measured, and were found to be remarkably well conserved between the oil, water, and all three devices. This indicates that SPMDs, PESDs, and ISPMDs should each be effective for source discrimination studies of petroleum contamination. PMID:13129510

Luellen, Drew R; Shea, Damian



Characterization and distribution of PAHs in surface sediments of Daliao River, China  

SciTech Connect

The concentrations of 16 priority pollutant PAHs in the samples of Daliao River were analyzed by a method based on Soxhlet extraction, solid-phase extraction clean-up and high performance liquid chromatography-programmable fluorescence/ultra violet detection. The total concentrations of PAHs in Daliao River ranged from 267.9 ng/g to 9,212 ng/g. The highest concentration of PAHs was 9,212 ng/g at the Station 24 (Anshan Railroad Bridge), and the lowest 267.9 ng/g at the Station 19 (Estuary). Compared with the total concentrations of PAHs of rivers in other parts of the world, the degree of contamination of Daliao River by PAHs was moderate to high. Specific compounds or groups of PAHs have been used as molecular markers to differentiate petrogenic and pyrogenic origin. The results showed that the main sources of PAHs in Daliao River were pyrolytic inputs such as combustion of coal, wood and petrogenic chemicals. The data was also compared by mean of two guideline values, an effects range-low (ER-L) and effects range-medium (ER-M), to assess the potential biological effects of the sediment adsorbed PAHs. It showed that the PAHs in some sites of Daliao River would exert adverse biological effects.

Zhang, J.X.; Ni, Y.W.; Yang, M.; Zhang, H.J.; Zhang, Q.; Chen, J.P. [Chinese Academy of Science, Dalian (China)



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

NASA Technical Reports Server (NTRS)

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.

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



The Investigation of Reducing PAHs Emission from Coal Pyrolysis by Gaseous Catalytic Cracking  

PubMed Central

The catalytic cracking method of PAHs for the pyrolysis gaseous products is proposed to control their pollution to the environment. In this study, the Py-GC-MS is used to investigate in situ the catalytic effect of CaO and Fe2O3 on the 16 PAHs from Pingshuo coal pyrolysis under different catalytic temperatures and catalyst particle sizes. The results demonstrate that Fe2O3 is effective than that of CaO for catalytic cracking of 16 PAHs and that their catalytic temperature corresponding to the maximum PAHs cracking rates is different. The PAHs cracking rate is up to 60.59% for Fe2O3 at 600°C and is 52.88% at 700°C for CaO. The catalytic temperature and particle size of the catalysts have a significant effect on PAHs cracking rate and CaO will lose the capability of decreasing 16 PAHs when the temperature is higher than 900°C. The possible cracking process of 16 PAHs is deduced by elaborately analyzing the cracking effect of the two catalysts on 16 different species of PAHs. PMID:24963507

Wang, Yulong; Zhao, Ruifang; Zhang, Chun; Li, Guanlong; Zhang, Jing; Li, Fan



Interrelationship of Pyrogenic Polycyclic Aromatic Hydrocarbon (PAH) Contamination in Different Environmental Media  

PubMed Central

Interrelationships between pyrogenic polycyclic aromatic hydrocarbons (PAHs) were assessed in air, soil, water, sediment, and tree leaves by using multi-media monitoring data. Concurrent concentration measurements were taken bimonthly for a year for the multi-media at urban and suburban sites. PAH level correlations between air and other media were observed at the urban site but were less clear at the suburban site. Considering a closer PAHs distribution/fate characteristics to soil than suspended solids, contamination in sediment seemed to be governed primarily by that in soil. The partitioning of PAHs in waters could be better accounted for by sorption onto black carbon and dissolved organic carbon. PMID:22303141

Kim, Seung-Kyu; Lee, Dong Soo; Shim, Won Joon; Yim, Un Hyuk; Shin, Yong-Seung



Mechanisms of biodegradation of polycyclic aromatic hydrocarbons (PAHs) by bacteria isolated from mangrove sediments.  

E-print Network

??Contamination of polycyclic aromatic hydrocarbons (PAHs) in coastal sediments is of great environmental concern because of their known or suspected toxic, mutagenic and carcinogenic hazards.… (more)

Zhou, Hongwei (???)



Anaerobic biodegradation of polycyclic aromatic hydrocarbons (PAHs) in the subsurface sediment of mangrove wetland.  

E-print Network

???Polycyclic aromatic hydrocarbons (PAHs) released into all environmental compartments through natural or anthropogenic activities are toxic, carcinogenic and mutagenic. Mangrove wetlands, located along the coastline… (more)

Li, Chunhua (???)



Enhancing the intrinsic bioremediation of PAH-contaminated anoxic estuarine sediments with biostimulating agents.  


Estuarine sediments are frequently polluted with hydrocarbons from fuel spills and industrial wastes. Polycyclic aromatic hydrocarbons (PAHs) are components of these contaminants that tend to accumulate in the sediment due to their low aqueous solubility, low volatility, and high affinity for particulate matter. The toxic, recalcitrant, mutagenic, and carcinogenic nature of these compounds may require aggressive treatment to remediate polluted sites effectively. In petroleum-contaminated sediments near a petrochemical industry in Gwangyang Bay, Korea, in situ PAH concentrations ranged from 10 to 2,900 microg/kg dry sediment. To enhance the biodegradation rate of PAHs under anaerobic conditions, sediment samples were amended with biostimulating agents alone or in combination: nitrogen and phosphorus in the form of slow-release fertilizer (SRF), lactate, yeast extract (YE), and Tween 80. When added to the sediment individually, all tested agents enhanced the degradation of PAHs, including naphthalene, acenaphthene, anthracene, fluorene, phenanthrene, fluoranthene, pyrene, chrysene, and benzo[a]pyrene. Moreover, the combination of SRF, Tween 80, and lactate increased the PAH degradation rate 1.2-8.2 times above that of untreated sediment (0.01-10 microg PAH/kg dry sediment/day). Our results indicated that in situ contaminant PAHs in anoxic sediment, including high molecular weight PAHs, were degraded biologically and that the addition of stimulators increased the biodegradation potential of the intrinsic microbial populations. Our results will contribute to the development of new strategies for in situ treatment of PAH-contaminated anoxic sediments. PMID:16145545

Bach, Quang-Dung; Kim, Sang-Jin; Choi, Sung-Chan; Oh, Young-Sook



Historical changes in the concentrations of polycyclic aromatic hydrocarbons (PAHs) in Lake Peipsi sediments.  


The distribution of 11 individual polycyclic aromatic hydrocarbons (PAHs) was analysed in a (210)Pb dated sediment core from the deepest area of Lake Peipsi and in four surface sediment samples taken from littoral areas. According to the concentrations in the core three groups of PAHs may be distinguished: (1) relatively stable concentrations of PAHs within the whole studied time interval; (2) very low concentrations in sediments accumulated before intensive anthropogenic impact (from 19th century up to the 1920s) following a slight increase and (3) an overall increase in PAH concentrations since the 1920s up to the present. Comprehensive analysis of PAHs in the core and monitoring data obtained in the 1980s together with the lithology of sediments show that an increase of anthropogenically induced PAHs correlates well with the history of fuel consumption in Estonia and speaks about atmospheric long-distance transport of PAHs. The continuous increase of PAH concentrations since the 1920s do not support the earlier hypothesis about the dominating impact of the oil shale fired power plants near the lake, because their emissions decreased significantly in the 1990s. The concentration of PAHs in the deep lake core sample correlates well with the content of organic matter, indicating absorption and co-precipitation with plankton in the sediment. PMID:18270801

Punning, Jaan-Mati; Terasmaa, Jaanus; Vaasma, Tiit; Kapanen, Galina



Characterization of PAHs in the atmosphere of carbon black manufacturing workplaces.  


The objective of this study was set out to characterize the polycyclic aromatic hydrocarbon (PAH) content in the atmosphere of an oil furnace carbon black manufacturing plant located in southern Taiwan. A standard semi-volatile sampling train, the PS-1 sampler, was used to collect samples from eight areas, including the feedstock oil unloading, furnace, filtering/micro-pulverization, pelletizing, packaging, office/outside, office/inside, and boundary area, respectively. For each area, side-by-side static samples were collected simultaneously and a total of 16 samples were obtained. For each collected sample, the adsorbent-retained PAH content and the filter-retained PAH content were used directly to determine the concentrations of gaseous-phase PAHs and particle-bound PAHs, respectively. The gas chromatograph/mass spectrometer (GC/MS) technique was used for PAH analyses, and a total of 21 PAH species were determined. Results show the gaseous-phase PAHs accounted for only 69.2% of the total PAH content for samples collected from the packaging area, which was significantly lower than those samples collected from the rest of seven areas (ranging from 96.3 to 99.7%). The result is not so surprising since the packaging area had the highest dust concentration due to the releasing of carbon black dusts during the packaging process. In this study, we further examine the contribution of gaseous-phase PAHs to the total benzo[a]pyrene equivalent (BaP(eq)) content from the health-risk assessment view of point. It can be found the contribution of gaseous-phase PAHs to the total BaP(eq) content (63.1%) was quite comparable to the corresponding contribution to the total PAH content for samples collected from the packaging area. However, a different trend can be found for samples collected from the other seven areas, where the contributions of gaseous-phase PAHs to the total BaP(eq) content (ranging from 67.7 to 93.4%) were lower than the corresponding contributions to the total PAH content. The above results can be explained by PAH homologues that contained in both gaseous-phase and particle-bound PAHs. It was found the gaseous-phase PAHs contained higher fractions of less carcinogenic low molecular weight PAH homologues, whereas particle-bound PAHs contained higher fractions of more carcinogenic high molecular weight PAH homologues. Considering the contributions of gaseous-phase PAHs to both total PAH content and total BaP(eq) content were well above 50% for the eight studied areas, it is concluded that both particle-bound and gaseous-phase PAHs should be included for assessing the exposures of carbon black workers. PMID:11900904

Tsai, Perng Jy; Shieh, Hong Yong; Lee, Wen Jhy; Lai, Soon Onn



Identification of Gas Phase PAHs in Absorption Towards Protostellar Sources  

NASA Technical Reports Server (NTRS)

The infrared emission bands (also known as the UIR bands.) have recently been observed in absorption at 3.25 micrometers in the ices surrounding a few proto-stellar objects at 11.2 micrometers in MonR2, and at 6.2 micrometers towards two sources near the galactic center. The UIR bands have been observed in emission for many years, but identifying these bands has proven to be both difficult and contentious as no one has yet found a single material that provides a good match to the features. However, most investigators agree that some form of carbon-based material with aromatic bonds is the most likely candidate, and many arguments favor free molecules (polycyclic aromatic hydrocarbons, PAHs) as the carriers of at least the narrow emission bands. Since the emission arises not from a single molecule but from a family of molecules, identifying which PAHs are contributing to the infrared emission bands is difficult. The identification is further complicated by the fact that the emission at short wavelengths is dominated by small molecules while at long wavelengths it is dominated by large molecules. Thus, for example, the emission at 3.3 micrometers is from a different mix of molecules than those which produce the 11.2 micrometer band. To complicate matters further, the molecular mix includes both neutral and ionic species. In absorption, the same mixture of molecules contributes at all wavelengths and the molecules should be neutral, potentially simplifying comparisons with lab data. Also, absorption strengths measured in the lab are directly applicable to interstellar absorption bands without the need to model an emission spectrum of an unknown mixture of ionized and neutral PAHs. In this paper we show that a mixture of argon matrix isolated PAH molecules can reproduce the 3.25 micrometers absorption band seen in the ISO SWS spectra of four embedded Infrared sources, S140 IRS1, AFGL 2591, Elias 29, and AFGL 989. In section 2 we describe the ISO SWS data analysis and in section 3 discuss the results.

Bregman, Jesse D.; Temi, Pasquale; DeVincenzi, Donald L. (Technical Monitor)



Mutation analysis of PAH gene in patients with PKU in western Iran and its association with polymorphisms: identification of four novel mutations.  


Phenylketonuria (PKU) is an autosomal recessive disorder characterized by a mutation in the phenylalanine hydroxylase (PAH) gene. Untreated PKU can lead to mental retardation, seizures, and other serious medical problems. This study was designed to investigate the status of molecular defects in the PAH gene and their association with polymorphisms in Kurdish patients with PKU in the Kermanshah province, western Iran. The study was conducted on 27 unrelated patients with PKU over a 2-year period (from 2010 to 2012). All 13 exons plus exon-intron boundaries of the PAH gene were analyzed and we identified 15 different mutations, including two novel mutations, in 51 of the 54 mutant alleles (diagnostic efficiency of 94.4 %). IVS4 + 1G > C (c.441 + 1G > C) and IVS7 - 5 T > C (c.843 - 5 T > C) are novel mutations that have not been reported in the academic literature or the PAH locus database ( ); therefore, they may be specific to the Kurdish population. IVS2 + 5G > C and IVS9 + 5G > A were the two most prevalent mutations in our sample, with frequencies of 26 % and 17 %, respectively. The second most common mutations were p.R261X, IVS10 - 11G > A, p.K363 > Nfs and IVS7 - 5 T > C, with each showing a relative frequency of 7.4 %. All other detected mutations, including p.F55 > Lfs, p.R176X, p.R243Q, p.V230I, p.R243X, p.R261Q, IVS8 - 7A > G and p.E390G had frequencies of less than 4 %. The present study showed that there is a distinct difference in the characteristics of PAH mutations between the Kermanshah province and other parts of Iran, suggesting that Kermanshah may have a unique population distribution of PAH gene mutations. Iran lies on the route of major ancient movements of the Caucasian people toward the Mediterranean basin, and Kermanshah has previously been called the gateway to Asia. Most of the mutations identified in this study are common in the Mediterranean region. Therefore, our findings are consistent with the historical and geographical links between the Iranian population and the populations of Mediterranean region. PMID:24048906

Alibakhshi, Reza; Moradi, Keyvan; Mohebbi, Zahra; Ghadiri, Keyghobad



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


Polycyclic aromatic hydrocarbons (PAHs), heterocyclic PAHs (NSO-HETs), alkylated PAHs and phenols are known as the prevailing contaminants in groundwater at tar contaminated sites. Besides these local sources, the concentrations and the distribution in particular of NSO-HETs in environmental samples, such as rivers, have received notably less attention. To investigate their occurrence in river basins two sensitive analytical methods for the simultaneous extraction of 86 substances including NSO-HETs, classical EPA-PAHs, alkylated PAHs and phenols were developed: liquid-liquid extraction for the whole water phase and solid phase extraction for the dissolved water phase only. Solely GC-MS or additionally LC-MSMS for fractionated basic nitrogen heterocycles (N-HETs) were used for quantification. Limits of quantification were in the low ngL(-1) range. Concentrations were determined in 29 aqueous samples from 8 relatively large rivers located in Lower Saxony (Germany) and the North Sea. NSO-HETs had comparable or even higher sum concentrations than EPA-PAHs. N-HETs, especially acridine and quinolines with concentrations of up to 20ngL(-1) per substance, were predominant. PMID:25482976

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



Assessing The Presence, Charge And Size Of Pahs In Dense Clouds  

NASA Astrophysics Data System (ADS)

PAHs are observed to be present and abundant in nearly all phases of the galactic and extragalactic interstellar medium. To date, PAH emission bands at 3.28, 6.2, 7.7, 8.6, and 11.2 micron, have been most easily detected in regions where individual gas phase PAH molecules (neutrals and ions) become highly vibrationally excited by the ambient radiation field. While PAHs and closely related aromatic materials should be present throughout dense interstellar regions, PAH emission is quenched in cold dark dense clouds. In these regions, most PAHs should efficiently condense out onto dust grains, either as ‘pure’ solids or as ‘guest molecules’ in icy grain mantles, much as is the case for most other interstellar molecules and therefore give rise to IR absorption bands rather than emission features. Spectroscopic observations of dense cloud lines of sight show prominent absorption features at 6.0 µm and 6.8 µm. These absorption features are seen in infrared spectra of young stellar objects (YSOs) and quiescent dense cloud regions. While ice species can account for some of the absorption, much of the absorption remains unidentified. Since fundamental PAH vibrational modes fall in the wavelength region of the unidentified absorption, and they are ubiquitous constituent of the ISM, they are good candidates to account for some of this absorption. Using the NASA Ames PAH Infrared Spectral Database, which contains computationally and experimentally generated spectra of many PAH species that vary in size and charge state, we aim to determine the contribution of PAHs to the unidentified absorption. In addition, we will investigate differences in the physical characteristics (size, charge state) of PAHs in quiescent dense cloud versus YSO environments. This poster discusses the preliminary results of this project for which we gratefully acknowledge funding by NASA’s ADAP program and the URSA program, funded by the NASA EPOESS program.

Tran, Tin; Chiar, J. E.; Peeters, E.; Ricca, A.; Allamandola, L. J.; Mattioda, A. L.; Kress, M.



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

PubMed Central

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 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. 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

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



Comparative study for determination of some polycyclic aromatic hydrocarbons ‘PAHs' by a new spectrophotometric method and multivariate calibration coupled with dispersive liquid-liquid extraction  

NASA Astrophysics Data System (ADS)

A modified dispersive liquid-liquid extraction (DLLE) procedure coupled with spectrophotometric techniques was adopted for simultaneous determination of naphthalene, anthracene, benzo(a)pyrene, alpha-naphthol and beta-naphthol in water samples. Two different methods were used, partial least-squares (PLS) method and a new derivative ratio method, namely extended derivative ratio (EDR). A PLS-2 model was established for simultaneous determination of the studied pollutants in methanol, by using twenty mixtures as calibration set and five mixtures as validation set. Also, in methanol a novel (EDR) method was developed for determination of the studied pollutants, where each component in the mixture of the five PAHs was determined by using a mixture of the other four components as divisor. Chemometric and EDR methods could be also adopted for determination of the studied PAH in water samples after transferring them from aqueous medium to the organic one by utilizing dispersive liquid-liquid extraction technique, where different parameters were investigated using a full factorial design. Both methods were compared and the proposed method was validated according to ICH guidelines and successfully applied to determine these PAHs simultaneously in spiked water samples, where satisfactory results were obtained. All the results obtained agreed with those of published methods, where no significant difference was observed.

Abdel-Aziz, Omar; El Kosasy, A. M.; El-Sayed Okeil, S. M.



Bioaccumulation, biotransformation and DNA binding of PAHs in feral eel (Anguilla anguilla) exposed to polluted sediments: A field survey  

SciTech Connect

Samples of sediment and eel taken from six sites in Amsterdam with different levels of water pollution were analyzed for 16 parental PAHs. In addition, biliary PAH metabolites and hepatic PAH-DNA adducts were determined in the eel to evaluate biomonitoring techniques for PAH exposure. There was a clear difference between PAH profiles in sediments and eel. Mainly two- and three-ring PAHs were detected in eel, whereas four-ring PAHs predominated in the sediments. Because PAH bioaccumulation was highest in eel from the reference sites, tissue levels of the parental PAH are probably not the most accurate monitor of PAH exposure in fish. An elevated excretion of 1-OH pyrene (determined by synchronous scan fluorescence) was observed in the bile of fish from three of the four polluted sites, indicating that this parameter may be used as a biomarker for PAH exposure. A significant increase in PAH-DNA adduct levels was observed in the liver of eel from all polluted sites. Therefore, this parameter seems to be a sensitive biomarker for exposure to mutagenic and carcinogenic PAHs.

Oost, R. Van Der; Heida, H.; Satumalay, K. (OMEGAM Environmental Research Inst., Amsterdam (Netherlands)); Schooten, F.J. Van (Univ. of Limburg, Maastricht (Netherlands). Dept. of Health Risk Analysis and Toxicology); Ariese, F.; Vermeulen, N.P.E. (Free Univ. of Amsterdam (Netherlands))



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


Surface motility of the polycyclic aromatic hydrocarbon (PAH)-degrading Mycobacterium gilvum VM552 was tested on agar and agarose plates prepared with varying amounts of gelling agents in the presence and absence of phenanthrene. Extensive spreading, originating from the point of inoculation, was observed on the surfaces of plates prepared with up to 0.3% agar and up to 0.6% agarose. The spreading velocities were 15.8 mm d(-1) on 0.3% agar and 19.5 mm d(-1) on 0.3% agarose plates. No evidence was found of accelerated or directed surface motility towards PAH crystals. The morphology of spreading M. gilvum VM552 colonies depended on both the carbon source and the type and concentration of the gelling agent. In 0.3% agar plates, M. gilvum VM552 cells were organized in 1-2-mm-wide branches of 1-5 cm length, while on agarose they slid as a homogenous monolayer across the surface. Microscopic inspection of the colonies on agar surfaces suggested that formation of branches was the combined effect of: (i) cell division and growth at the tip of a branch; (ii) propulsion of cells from the mature basal parts of a branch towards the tip; and (iii) physiologically induced reduced friction between cells and agar. Similar surface migration patterns were observed for the anthracene-degrading M. frederiksbergense LB501T. PMID:18440203

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



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)

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.

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



Determination of Polycyclic Aromatic Hydrocarbons (PAH) and Their Metabolites in Blood, Feces, and Urine of Rats Orally Exposed to PAH Contaminated Soils  

Microsoft Academic Search

.   Polycyclic aromatic hydrocarbons (PAH) have become an ubiquitous upper soil component as a consequence of industrialization\\u000a involving a multitude of combustion processes. Ingestion of PAH contaminated soil is considered to be a major exposure route,\\u000a specifically for small children living on these soils. Health risk assessment is based on extrapolations from data obtained\\u000a via studies performed with pure chemicals.

F. J. van Schooten; E. J. C. Moonen; L. van der Wal; J. C. S. Kleinjans



Polycyclic aromatic hydrocarbon (PAH) metabolites in marine fishes as a specific biomarker to indicate PAH pollution in the marine coastal environment  

Microsoft Academic Search

In this study, analysis methods for the PAH metabolites of naphthalene (Na), pyrene (Py) and benzo(a)pyrene (BaP) with different benzo-rings (2-4-5 rings respectively) were developed and the metabolism kinetics of Py and BaP in marine fishes were studied. Two PAH metabolites of Na and Py, namely 1-naphthol (1-OH Na) and 1-hydroxy pyrene (1-OH Py), were determined using the fixed wavelength

Xin H. Wang; Hua S. Hong; Jing L. Mu; Jian Q. Lin; Shong H. Wang



Polycyclic aromatic hydrocarbons (PAHs) reduce hepatic ?-oxidation of fatty acids in chick embryos.  


Polycyclic aromatic hydrocarbons (PAHs) are widespread fused-ring contaminants formed during incomplete combustion of almost all kind of organic materials from both natural and anthropogenic sources. Some PAHs have been shown to be carcinogenic to humans, and a wide range of PAHs are found in wildlife all around the globe including avian species. The purpose of this project was to assess the effects of a standard mixture of 16 PAHs (United States Environmental Protection Agency) on the hepatic fatty acid ?-oxidation in chicken embryos (Gallus gallus domesticus) exposed in ovo. The hepatic ?-oxidation was measured using a tritium release assay with [9,10-(3)H]-palmitic acid (16:0) as substrate. Treated groups were divided into groups of 0.05, 0.1, 0.3, 0.5, and 0.8 mg PAHs/kg egg weight. The hepatic ?-oxidation was reduced after exposure in ovo to the 16 PAHs mixture compared to control. The mechanisms causing reduced fatty acid oxidation in the present study are unclear, however may be due to deficient membrane structure, the functionality of enzymes controlling the rate of fatty acid entering into the mitochondria, or complex pathways connected to endocrine disruption. To the best of our knowledge, this is the first time a PAH-caused reduction of hepatic ?-oxidation of fatty acids in avian embryos has been observed. The implication of this finding on risk assessment of PAH exposure in avian wildlife remains to be determined. PMID:23274806

Westman, Ola; Nordén, Marcus; Larsson, Maria; Johansson, Jessica; Venizelos, Nikolaos; Hollert, Henner; Engwall, Magnus



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


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) 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(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 between total PCDD/Fs and total PAHs, although no such relationship has been found for TEQ. PMID:23462270

Chen, Ying; Zhao, Rongzhi; Xue, Jun; Li, Jinhui



Measurement of gaseous PAHs with an innovative passive sampler in community exposure studies  

EPA Science Inventory

A sensitive, simple, and cost-effective passive sampling methodology was developed to quantify gaseous polycyclic aromatic hydrocarbons (PAHs) in personal, indoor and outdoor air. A Fan-Lioy passive PAH sampler (FL-PPS) is constructed from four 80 sections of 1 cm long SPB-5 GC c...


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

USGS Publications Warehouse

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

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



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

USGS Publications Warehouse

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.

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



The effectiveness of phytoremediation as a secondary treatment for aged polycyclic aromatic hydrocarbons (PAHs) in soil  

Microsoft Academic Search

Polycyclic aromatic hydrocarbons (PAHs) are potentially carcinogenic compounds found in high concentrations in manufactured gas plant (MGP) residues. However, PAHs in soils contaminated with these residues are often highly resistant to degradation, particularly after the soils have been remediated with conventional techniques such as composting or land treatment. Phytoremediation holds promise as a finishing procedure for traditional approaches when significant

Zakia Denise Parrish



Analysis of smoke PAHs from selected Taiwanese cigarettes by using molecular imprinting polymers  

Microsoft Academic Search

Polycyclic aromatic hydrocarbons (PAHs) and their derivatives are common trace pollutants produced during incomplete combustion of organic substances, such as tobacco. After sampling cigarette smoke, PAH collators must undergo pretreatment processes such as extraction, cleanup and concentration before instrument analysis. This study combines molecular imprinted polymers (MIPs) and solid-phase extraction (SPE) to create a novel sample pretreatment technique. Experimental results

Wei L. Ho; Ta C. Lin; Yu Y. Liu; Jiun A. Chen



[Emission factors of polycyclic aromatic hydrocarbons (PAHs) in residential coal combustion and its influence factors].  


As the emission source of polycyclic aromatic hydrocarbons (PAHs), domestic coal combustion has attracted increasing attention in China. According to the coal maturity, combustion form and stove type associated with domestic coal combustion, a large-size, full-flow dilution tunnel and fractional sampling system was employed to collect the emissions from five coals with various maturities, which were burned in the form of raw-coal-chunk (RCC)/honeycomb-coal-briquettes (HCB) in different residential stoves, and then the emission factors of PAHs (EF(PAHs)) were achieved. The results indicate that the EF(PAHs) of bituminous coal ranged from 1.1 mg x kg(-1) to 3.9 mg x kg(-1) for RCC and 2.5 mg x kg(-1) to 21. 1 mg x kg(-1) for HCB, and the anthracite EF(PAH8) were 0.2 mg x kg(-1) for RCC and 0.6 mg x kg(-1) for HCB, respectively. Among all the influence factors of emission factors of PAHs from domestic coal combustion, the maturity of coal played a major role, the range of variance reaching 1 to 2 orders of magnitude in coals with different maturity. Followed by the form of combustion (RCC/HCB), the EF(PAHs) of HCB was 2-6 times higher than that of RCC for the same geological maturity of the coal. The type of stove had little influence on EF(PAHs). PMID:24027979

Hai, Ting-Ting; Chen, Ying-Jun; Wang, Yan; Tian, Chong-Guo; Lin, Tian



Investigation of the release of PAHs from artificially contaminated sediments using cyclolipopeptidic biosurfactants.  


Polycyclic aromatic hydrocarbons (PAHs) can be preponderant in contaminated sediments and understanding how they are sorbed in the different mineral and organic fractions of the sediment is critical for effective removal strategies. For this purpose, a mixture of seven PAHs was studied at the sediment/water interface and sorption isotherms were obtained. The influence of various factors on the sorption behavior of PAHs was evaluated, such as the nature of minerals, pH, ionic strength and amount of organic matter. Afterwards, the release of PAHs from the sediment by surfactants was investigated. The effectiveness of sodium dodecyl sulfate (SDS) was compared to natural biosurfactants, of cyclolipopeptidic type (amphisin and viscosin-like mixture), produced by two Pseudomonas fluorescens strains. The desorption of PAHs (from naphthalene to pyrene), from the highly retentive kaolinite fraction, could be favored by adding SDS or amphisin, but viscosin-like biosurfactants were only effective for 2-3 ring PAHs desorption (naphthalene to phenanthrene). Moreover, while SDS favors the release of all the target PAHs from a model sediment containing organic matter, the two biosurfactants tested were only effective to desorb the lowest molecular weight PAHs (naphthalene to fluorene). PMID:23995556

Portet-Koltalo, F; Ammami, M T; Benamar, A; Wang, H; Le Derf, F; Duclairoir-Poc, C



Nonadditive effects of PAHs on Early Vertebrate Development: mechanisms and implications for risk assessment  

PubMed Central

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants. Traditionally, much of the research has focused on the carcinogenic potential of specific PAHs, such as benzo(a)pyrene, but recent studies using sensitive fish models have shown that exposure to PAHs alters normal fish development. Some PAHs can induce a teratogenic phenotype similar to that caused by planar halogenated aromatic hydrocarbons, such as dioxin. Consequently, mechanism of action is often equated between the two classes of compounds. Unlike dioxins, however, the developmental toxicity of PAH mixtures is not necessarily additive. This is likely related to their multiple mechanisms of toxicity and their rapid biotransformation by CYP1 enzymes to metabolites with a wide array of structures and potential toxicities. This has important implications for risk assessment and management as the current approach for complex mixtures of PAHs usually assumes concentration addition. In this review we discuss our current knowledge of teratogenicity caused by single PAH compounds and by mixtures and the importance of these latest findings for adequately assessing risk of PAHs to humans and wildlife. Throughout, we place particular emphasis on research on the early life stages of fish, which has proven to be a sensitive and rapid developmental model to elucidate effects of hydrocarbon mixtures. PMID:18156145

Billiard, Sonya M.; Meyer, Joel N.; Wassenberg, Deena M.; Hodson, Peter V.; Di Giulio, Richard T.



Monitoring and classification of PAH toxicity using an immobilized bioluminescent bacteria  

Microsoft Academic Search

An immobilized recombinant bioluminescent Escherichia coli strain, harboring a lac::luxCDABE fused plasmid, which shows lower bioluminescence levels when cellular metabolism is inhibited, was used to monitor the cellular toxicity of polycyclic aromatic hydrocarbons (PAHs). PAHs, classified as pericondensed (PCPAHs) or catacondensed (CCPAHs) according to their molecular structures, were differentiable according to the response of this biosensor. Only CCPAHs were found

Hyun Joo Lee; Julien Villaume; David C. Cullen; Byoung Chan Kim; Man Bock Gu



Using chemical desorption of PAHs from sediment to model biodegradation during bioavailability assessment.  


This work compares the biodegradation potential of four polycyclic aromatic hydrocarbons (PAH) (phenanthrene, pyrene, chrysene and benzo(a)pyrene, chosen as representatives of the 3, 4 and 5 ring PAHs) with their desorption from sediment by XAD4 resin and methyl-?-cyclodextrin (MCD). The biodegradation study was conducted under various conditions (biostimulation, bioaugmentation and their combination). The results show that total PAH removal in all treatments except biostimulation gave similar results, whereby the total amount of PAHs was decreased by about 30-35%. The desorption experiment showed that XAD4 desorbed a greater fraction of phenanthrene (77% versus 52%), and benzo(a)pyrene (44% versus 25%) than MCD. The results for four ring PAHs were similar for both desorption agents (about 30%). Comparing the maximum biodegraded amount of each PAH with the rapidly desorbed XAD4 and MCD fraction, XAD4 was found to correlate better with biodegradation for the high molecular PAHs (pyrene, chrysene, benzo(a)pyrene), although it overestimated the availability of phenanthrene. In contrast, MCD showed better correlation with the biodegradation of low molecular weight PAHs. PMID:25261761

Spasojevi?, Jelena M; Maleti?, Snežana P; Ron?evi?, Sr?an D; Radnovi?, Dragan V; Cu?ak, Dragana I; Tri?kovi?, Jelena S; Dalmacija, Božo D



Health Implications of PAH Release from Coated Cast Iron Drinking Water Distribution Systems in the Netherlands  

PubMed Central

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

van de Ven, Bianca M.; de Jongh, Cindy M.




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...



EPA Science Inventory

The PAHs in Air data set contains the analytical results for measurements of up to 22 polynuclear aromatic hydrocarbons (PAHs) in air samples taken indoors and outdoors. The information is for 172 samples for 86 households. Active samples were taken by pumping standardized air ...



EPA Science Inventory

The PAHs in Food data set contains the analytical results for measurements of up to 19 polynuclear aromatic hydrocarbons (PAHs) in 86 samples over 86 households. Each sample was collected as a duplicate of the solid food consumed by the primary respondent within a single 24-hour...



EPA Science Inventory

The PAHs in Dust data set contains the analytical results for measurements of up to 21 polynuclear aromatic hydrocarbons (PAHs) in 91 dust samples over 91 households. Samples were taken by collecting dust from the indoor floor areas from the main room and in the bedroom of the p...



EPA Science Inventory

The PAHs in Soil data set contains the analytical results for measurements of up to 19 polynuclear aromatic hydrocarbons (PAHs) in 91 soil samples over 91 households. Samples were collected 10 feet perpendicular to the foundation of the home. The sample consists of an aliquot ...


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

PubMed Central

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 ?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. PMID:20063893



Removal of polycyclic aromatic hydrocarbons (PAHs) from sewage sludge by anaerobic degradation  

Microsoft Academic Search

Due to the hydrophobic nature of the polyaromatic hydrocarbons (PAHs) they are mostly bound to the sludge and escape aerobic treatment in a wastewater treatment plant. They therefore proceed directly to the anaerobic post treatment, terminate in the sludge, and can be released to the environment if land spreading is used. PAH degradation in anaerobic methanogenic systems has only recently

N. Christensen; D. J. Batstone; Z. He; I. Angelidaki; J. E. Schmidt



PAH biotransformation in terrestrial invertebrates—a new phase II metabolite in isopods and springtails  

Microsoft Academic Search

Soil-living invertebrates are exposed to high concentrations of contaminants accumulating in dead organic matter, such as polycyclic aromatic hydrocarbons (PAHs). The capacity for PAH biotransformation is not equally developed in all invertebrates. In this paper, we compare three species of invertebrates, Porcellio scaber (Isopoda), Eisenia andrei (Lumbricidae) and Folsomia candida (Collembola), for the metabolites formed upon exposure to pyrene. Metabolic

Gerard J. Stroomberg; Herman Zappey; Ruud J. C. A. Steen; Cornelis A. M. van Gestel; Freek Ariese; Nel H. Velthorst; Nico M. van Straalen



Catalysis of PAH biodegradation by humic acid shown in synchrotron infrared studies  

Microsoft Academic Search

The role of humic acid (HA) in the biodegradation of toxic polycyclic aromatic hydrocarbons (PAHs) has been the subject of controversy, particularly in unsaturated environments. By utilizing an infrared spectromicroscope and a very bright, nondestructive synchrotron photon source, we monitored in situ and, over time, the influence of HA on the progression of degradation of pyrene (a model PAH) by

Hoi-Ying N. Holman; Karl Nieman; Darwin L. Sorensen; Charles D. Miller; Michael C. Martin; Thomas Borch; Wayne R. McKinney; Ronald C. Sims



PAHs in Road Dust: Ubiquity, Fate and Summary of Available Data  

Microsoft Academic Search

Poly aromatic hydrocarbons (PAH) are ubiquitous in environment and are also present in road dust in urban and rural locations worldwide due to the mere presence of even a weak primary source and the dynamic interconnection amongst all environmental segments. Although monitoring and assessment of PAHs in road dust have been undertaken in several countries, compilation of information on dynamics

Deepanjan Majumdar; Bhargavi Rajaram; Shweta Meshram; C. V. Chalapati Rao



PAHs in Road Dust: Ubiquity, Fate, and Summary of Available Data  

Microsoft Academic Search

Polyaromatic hydrocarbons (PAH) are ubiquitous in environment and are also present in road dust in urban and rural locations worldwide due to the mere presence of even a weak primary source and the dynamic interconnection among all environmental segments. Although monitoring and assessment of PAHs in road dust have been undertaken in several countries, compilation of information on the dynamics

Deepanjan Majumdar; Bhargavi Rajaram; Shweta Meshram; C. V. Chalapati Rao



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


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 40wt.% to 70wt.%. For PS, PET and lignin, PAH may be generated directly from the aromatic structure of the feedstock. PMID:25312776

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



Source apportionment of sediment PAHs in Lake Calumet, Chicago: application of factor analysis with nonnegative constraints.  


A factor analysis model with nonnegative constraints (FA) was used to apportion the sources of PAHs found in sediments of Lake Calumet and surrounding wetlands in southeast Chicago. Source profiles and contributions, with uncertainties, are determined with no prior knowledge of sources. The model includes scaling and backscaling of data with average PAH concentrations without sample normalization. This work is a follow-up to a study that used a chemical mass balance (CMB8.2) model to apportion sources to the same data set. Literature source profiles, modified based on gas/particle partitioning of individual PAHs, from eight PAH sources were considered for comparison. FA results for a two-source solution indicate coke oven (45%) and traffic (55%) are the primary PAH sources to Lake Calumet sediments. A six-source FA solution indicates that coke oven (47%) and traffic (45%) related sources are major PAH sources and wood burning-coal residential (2.3%) is a minor PAH source. From the six-source solution, two coke oven profiles are observed, a standard coke oven profile (33%), and a degraded or second coke oven profile (14%) low in phenanthrene and pyrene. Observed traffic related sources include gasoline engine (36%) exhaust and traffic tunnel air (9.3%). This work supports the previous study of Lake Calumet PAHs by CMB model. In addition, FA provides new insights since wood burning and secondary coke oven profiles were not recognized in the CMB model. PMID:14740723

Bzdusek, Philip A; Christensen, Erik R; Li, An; Zou, Qimeng



Non-destructive assessment of polycyclic aromatic hydrocarbon (PAH) exposure by fluorimetric analysis of crab urine  

Microsoft Academic Search

The detection of urinary polycyclic aromatic hydrocarbon (PAH) metabolites by fluorescence spectrophotometry is particularly effective as a practical means to assess PAH exposure in decapod crabs. However, the practical application of this technique has thus far only been tested for the European shore crab (Carcinus maenas) and only a few field studies have been conducted in heavily polluted areas. The

Samuel Koenig; Candida Savage; Jonathan P. Kim




EPA Science Inventory

An instrument for real-time monitoring of polycyclic aromatic hydrocarbons (PAH) on airborne fine particles was evaluated for use in indoor and ambient air measurements. he instrument is based on photoelectric ionization of surface PAH, loss of the photoelectrons, and subsequent ...


PAHs in indoor dust samples in Shanghai's universities: levels, sources and human exposure.  


Given the significant amount of time people spend indoors, the occurrence of polycyclic aromatic hydrocarbons (PAHs) in indoor dust and their potential risks are of great concern. In the present study, ten dust samples from lecture theatres and twelve samples from dining halls were collected from university campuses in Shanghai to investigate the PAH levels, possible sources and human exposure. The total concentrations of 18 PAHs ranged from 9.84 to 21.44 ?g/g for dust samples from lecture theatres, and 9.63-44.13 ?g/g for samples from dining halls. Total PAH concentrations in indoor dust samples showed a better correlation to black carbon compared to total organic carbon contents. PAHs in dining halls samples showed a similar distribution pattern with that of commercial kitchen air, which indicated that cooking activities could contribute most of the PAHs found in dining halls. Principal component analysis revealed both petrogenic and pyrogenic sources. The potential health risk for PAHs was assessed in terms of BaP equivalent carcinogenic power and estimated daily intake (EDI). Relatively high EDI values compared to other studies suggested that PAHs posed a potential threat to human health in indoor environments at Shanghai's universities. PMID:22527117

Peng, Huan; Yang, Yi; Liu, Min; Zhou, John L




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...


Bioremediation of Poly-Aromatic Hydrocarbon (PAH)Contaminated Soil by Composting  

Microsoft Academic Search

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

Nadine Loick; Phil J. Hobbs; Mike D. C. Hale; Davey L. Jones



Natural attenuation, biostimulation and bioaugmentation on biodegradation of polycyclic aromatic hydrocarbons (PAHs) in mangrove sediments  

PubMed Central

The biodegradability of a mixture of PAHs, namely fluorene (Fl), phenanthrene (Phe) and pyrene (Pyr), in mangrove sediment slurry was investigated. At the end of week 4, natural attenuation based on the presence of autochthonous microorganisms degraded more than 99% Fl and Phe but only around 30% of Pyr were degraded. Biostimulation with addition of mineral salt medium degraded over 97% of all three PAHs, showing that nutrient amendment could enhance Pyr degradation. Bioaugmentation with inoculation of a PAH-degrading bacterial consortium enriched from mangrove sediments did not show any promotion effect and the degradation percentages of three PAHs were similar to that by natural attenuation. Some inhibitory effect was observed in bioaugmentation treatment in week 1 with only 50% Fl and 70% Phe degraded. These results indicate that autochthonous microbes may interact and even compete with the enriched consortium during PAH biodegradation. Natural attenuation appeared to be the most appropriate way to remedy Fl- and Phe-contaminated mangrove sediments while biostimulation was more capable to degrade Pyr-contaminated sediments. The study also shows that although a large portion of the added PAHs (more than 95%) was adsorbed onto the sediments at the beginning of the experiment, most PAHs were degraded in 4 weeks, suggesting that the degraders could utilize the adsorbed PAHs efficiently. PMID:16023146

Yu, K.S.H.; Wong, A.H.Y.; Yau, K.W.Y.; Wong, Y.S.; Tam, N.F.Y.




EPA Science Inventory

The fate of 14 polycyclic aromatic hydrocarbon (PAH) compounds was evaluated with regard to interphase transfer potential and mechanisms of treatment in soil under unsaturated conditions. olatilization and abiotic and biotic fate of the PAHs were determined using two soils not pr...



EPA Science Inventory

The fate of 14 polycyclic aromatic hydrocarbon (PAH) compounds was evaluated with regard to interphase transfer potential and mechanisms of treatment in soil under unsaturated conditions. Volatilization and abiotic and biotic fate of the PAHs were determined using two soils not p...


Sorption effects interfering with the analysis of polycyclic aromatic hydrocarbons (PAH) in aqueous samples.  


Polycyclic aromatic hydrocarbons (PAH) are severe environmental pollutants that are analyzed frequently. The risk assessment of PAH impact to groundwater can be performed using leaching tests. Therby a liquid-solid separation step including centrifugation may be required, which in turn might lead to loss of analytes due to sorption on the equipment. Thus we determined the PAH recoveries from various container materials (polyethylene (PE), polypropylene (PP), polytetraflourethylene (PTFE), stainless steel (ES), and perflouroalkoxy (PFA)) and compared them to selected PAH properties. We found the best recoveries for PFA (68%) and PTFE (65%) containers. We found good negative correlations (-0.93 and better) between PAH recovery and log partition coefficient organic carbon-water (logKOC) for PFA, PTFE, and ES containers. PMID:24720977

Krüger, Oliver; Kalbe, Ute; Meißner, Kerstin; Sobottka, Sebastian



PAHs reduce DNA synthesis and delay cell division in the widespread primary producer Prochlorococcus.  


The cyanobacteria Prochlorococcus is the most abundant primary producer in the ocean. In a global study across the Atlantic, Indian and Pacific Oceans, we tested the effect of organic pollutants on the growth and cell division of natural Prochlorococcus populations. Sub-lethal concentrations of Polycyclic Aromatic Hydrocarbons (PAHs) altered Prochlorococcus cell division by reducing DNA synthesis and decreasing the percentage of cells entering mitosis. Cell division time increased with PAHs dosage by 1.2 h per ?g L(-1) of mixture added. At PAHs dosages >1 ?g L(-1), Prochlorococcus cell division tended to arrest at S-phase (DNA synthesis). As a consequence, population growth was significantly reduced in the presence of PAHs. The presence of PAHs resulted in a predictable alteration of the cell cycle of the widespread cyanobacteria. The dosages tested are above concentrations in the open ocean, but found in the coastal ocean, where Prochlorococcus growth must be inhibited. PMID:25463708

Cerezo, Maria Isabel; Agustí, Susana



Mass balance-based regression modeling of PAHs accumulation in urban soils, role of urban development.  


We investigated the polycyclic aromatic hydrocarbons (PAHs) contents in 68 soils samples collected at housing developments that represent different length of development periods across Beijing. Based on the data, we derived a mass balanced mathematical model to simulate the dynamics of PAH accumulations in urban soils as affected by the urban developments. The key parameters were estimated by fitting the modified mass balance model to the data of PAH concentrations vs. building age of the sampling green area. The total PAH concentrations would increase from the baseline of 267 ng g(-1) to 3631 ng g(-1) during the period of 1978-2048. It showed that the dynamic changes in the rates of accumulations of light and heavy PAH species were related to the shifting of sources of fuels, combustion efficiencies, and amounts of energy consumed during the course of development. PMID:25489746

Peng, Chi; Wang, Meie; Chen, Weiping; Chang, Andrew C



Tracing the PAH-YSO Relationship in Nine LMC Star-Forming Regions  

NASA Astrophysics Data System (ADS)

I present the discovery of over 1000 Young Stellar Objects (YSOs) in nine diverse star-forming regions in the Large Magellanic Cloud (Carlson et al. 2012 A&A 542, 66). These sources are color-selected in the infrared using SAGE Spitzer IRAC bands and MIPS 24?m, and their spectral energy distributions are fit as in Robitaille et al. (2007) to determine their approximate physical characteristics and evolutionary stages. I then look at the physical distribution of emission from polycyclic-aromatic hydrocarbons (PAHs) in these regions by comparing IRAC fluxes as in Povich et al. (2007) and identifying YSOs with significant PAH emission. The clearest PAH tracer is 8?m/4.5?m, as the [8.0] encompasses the strong 7.7?m feature, while the [4.5] has no PAH contribution. The YSO and PAH distributions are compared.

Carlson, Lynn R.; Galaxy Evolution), SAGE (Surveying the Agents of



Partitioning of PAHs in pore water from mangrove wetlands in Shantou, China.  


To investigate the trend of selected polycyclic aromatic hydrocarbons (PAHs) partitioning, fifteen pore water samples collected from the sediments of three mangrove wetlands were analyzed, and the partition coefficients and the partition model for the PAHs were determined by the correlation between K(oc) and octanol-water partition coefficient (K(ow)). The results revealed that the mean Kp values in inner mangrove wetlands were between 143 and 1031 L /Kg; the particulate organic carbon (POC) could strongly adsorb low-ring PAHs; the PAHs partitioning was on a obvious trend transported to particle phase. We suggest that the classic equilibrium model of organic carbon normalized (K(p)=K(oc)f(oc)) may be used to predict the trend of the selected PAHs partitioning. PMID:25450913

Cao, Qi min; Wang, Hua; Qin, Jian qiao; Chen, Gui zhu; Zhang, Yong bei



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

NASA Technical Reports Server (NTRS)

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.

Salama, Farid



Results of PAH screening in floodplain soils vs. soil quality standards  

NASA Astrophysics Data System (ADS)

A focus on soil quality issues in the EU has resulted in extensive studies aimed to development of a Soil Framework Directive, in parallel with setting up a harmonized European Soil Monitoring System. Polycyclic Aromatic Hydrocarbons (PAHs) belong to the most problematic contaminants to be monitored and controlled. This study presents the screening survey for 16 PAHs carried out in 2000 in the area severely impacted by the catastrophic flood of 1997 in the Odra River valley in Poland, Czech Republic and Germany. Within this survey, 16 PAH contents in soils due to river sediments deposition resulting from the flood, and the effect of flood on the distribution of PAHs in soils of the area were assessed in view of soil quality standards and need for remediation. The post-flood PAH spatial distribution with use of the Geographical Information System (GIS) showed distinct correlation with floodwater flow conditions, while total 16 PAH and specific compounds concentrations in the soil layer 0-0.20 m appeared to be mostly within the standard limits. In 17% of composite samples, 16PAH concentrations were found to be considerably elevated, up to the values > 1000 ?g/kg exceeding the standards for agricultural soils in particular samples. PAH compounds displayed also different vertical migration potential in soils. The occurrence of the maximum PAH concentrations in the floodwater stagnation areas confirmed river sediments to be the major source of these compounds. The qualitative composition of 16 PAHs (ANty < Flth < CHR < BaA < PYR) in humus layer of soils in these areas denoted anthropogenic sources of these compounds.

Twardowska, Irena; Janta-Koszuta, Krystyna; Stefaniak, Sebastian; Kyziol, Joanna



Relationship between PAHs Concentrations in Ambient Air and Deposited on Pine Needles  

PubMed Central

Objectives This study was carried out to determine whether or not pine needles can be used as passive samplers of atmospheric polycyclic aromatic hydrocarbons (PAHs) using the correlation between accumulated PAH concentrations in air (Ca, ng/m3) and those deposited on pine needles (Cp, ng/g dry). Methods PAHs in ambient air was collected using low volume PUF sampler and pine needles was gathered at same place for 7 months. Results good correlation (R2=0.8582, p<0.05) was found between Ca and Cp for PAHs with a higher gaseous state in air (AcPy, Acp, Flu, Phen, Ant, Flt, Pyr, BaA and Chry), but there was a poorer correlation (R2=0.1491, p=0.5123) for the PAHs with a lower gaseous state (BbF, BkF, BaP, DahA, BghiP and Ind123). A positive correlation (R2=0.8542) was revealed between the logarithm of the octanol-air partitioning coefficient (logKoa) and Cp/Ca for the PAHs with a higher gaseous state in air, but there was a negative correlation (R2=0.8131) for the PAHs with a lower gaseous state. The Ca-Cp model could not be used to estimate PAHs concentrations in air using deposited PAHs concentrations on pine needles, but the logKoa-Cp/Ca model could be used. Conclusions It was found that pine needles can be used as passive samplers of atmospheric PAHs. PMID:22125765



Polycyclic aromatic hydrocarbons (PAHs) in Antarctic Martian meteorites, carbonaceous chondrites, and polar ice  

SciTech Connect

Recent analyses of the carbonate globules present in the Martian meteorite ALH84001 have detected polycyclic aromatic hydrocarbons (PAHs) at the ppm level. The distribution of PAHs observed in ALH84001 was interpreted as being inconsistent with a terrestrial origin and were claimed to be indigenous to the meteorite, perhaps derived from an ancient martian biota. We have examined PAHs in the Antarctic shergottite EETA79001, which is also considered to be from Mars, as well as several Antarctic carbonaceous chondrites. We have found that many of the same PAHs detected in the ALH84001 carbonate globules are present in Antarctic carbonaceous chondrites and in both the matrix and carbonate (druse) component of EETA79001. We also investigated PAHs in polar ice and found that carbonate is an effective scavenger of PAHs in ice meltwater. Moreover, the distribution of PAHs in the carbonate extract of Antarctic Allan Hills ice is remarkably similar to that found in both EETA79001 and ALH84001. The reported presence of L-amino acids of apparent terrestrial origin in the EETA79001 druse material suggests that this meteorite is contaminated with terrestrial organics probably derived from Antarctic ice meltwater that had percolated through the meteorite. Our data suggests that the PAHs observed in both ALH84001 and EETA79001 are derived from either the exogenous delivery of organics to Mars or extraterrestrial and terrestrial PAHs present in the ice meltwater or, more likely, from a mixture of these sources. It would appear that PAHs are not useful biomarkers in the search for extinct or extant life on Mars. 33 refs., 3 figs., 1 tab.

Becker, L. [Univ. of California, San Diego, La Jolla, CA (United States)] [Univ. of California, San Diego, La Jolla, CA (United States); [National Aeronautics and Space Administration, Moffett Field, CA (United States); Glavin, D.P.; Bada, J.L. [Univ. of California, San Diego, La Jolla, CA (United States)] [Univ. of California, San Diego, La Jolla, CA (United States)



Chemical Oxidation of Complex PAH Mixtures by Base-activated Sodium Persulfate  

NASA Astrophysics Data System (ADS)

In situ chemical oxidation (ISCO) is an attractive approach for the remediation of recalcitrant soil and groundwater contaminants. One oxidant that has received significant recent attention is sodium persulfate, which has several advantages, including a relatively long lifetime in porous media, the ability to destroy a wide-range of chemical contaminants, and a high oxidation potential. In this study, we investigated the chemical mechanisms associated with base-activated persulfate oxidation of polycyclic aromatic hydrocarbons (PAHs) and assessed the applicability of persulfate to the remediation of porous media contaminated with non-aqueous phase liquid (NAPL) PAH mixtures. Batch experiments were conducted to determine the oxidation kinetics for individual PAH compounds, synthetic PAH mixtures, and manufactured gas plant (MGP) tars. Additional experiments were conducted with added surfactants (Triton X-100, Triton X-45, and Tween 80) to increase PAH mass transfer from the NAPL to the aqueous phase, and with radical scavengers (ethanol and tert-butyl alcohol) to identify the reactive species responsible for degradation. Degradation of total PAHs in the NAPL experiments was as high as 70%. The addition of surfactant increased initial PAH degradation rates, but also greatly increased the rate of base consumption, thereby reducing the overall fraction degraded. The degradation of individual PAHs within the NAPLs varied significantly, with the masses of some compounds remaining largely unchanged. The results of the radical scavenger and single PAH experiments suggest that the observed pattern of degradation in PAH mixtures is the result of a combination of mass transfer considerations and competition for radical species.

Hauswirth, S.; Miller, C. T.



Binding of polycyclic aromatic hydrocarbons (PAHs) to teleost aryl hydrocarbon receptors (AHRs).  


Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous, environmental contaminants that pose a potential risk to fish populations. Both field and laboratory studies suggest that exposure of the early life stages of fish to PAH can mimic the embryotoxic effects of the planar halogenated hydrocarbons (PHHs), the most potent of which is 2,3,7,8-tetrachlorodibenzo-p-dioxin. PHH toxicity is mediated by the aryl hydrocarbon receptor (AHR) and PHH potency is predicted by its AHR-binding affinity and CYP1A induction potency. However, the role of the AHR, if any, in mediating the developmental effects of PAH to fish remains unknown. In this study we looked at the AHR binding affinity of a test set of PAH that had been previously ranked for their potency for inducing teleost CYP1A. PAH that induced CYP1A inhibited [3H]TCDD binding to in vitro-expressed AHRs from rainbow trout and the AHR expressed in PLHC-1 fish hepatoma cells. Generally, the relative rank order for AHR binding affinity predicted the rank order of these same PAH for inducing CYP1A reported in other studies. There was a strong, positive relationship between binding to the PLHC-1 AHR (stimulus) and the EC50s for CYP1A induction (response) in whole juvenile trout and in RTL-W1 cells, but EC50s were much higher than expected for a 1:1 stimulus/response relationship. These data show that the ability of PAH to bind to teleost AHR predicts PAH potency for CYP1A induction. If PAH toxicity is receptor-mediated and predicted by induction potencies, we will have a powerful mechanistic-based tool for rapidly assessing the risk of toxicity to fish of PAH from any source. PMID:12223212

Billiard, Sonya M; Hahn, Mark E; Franks, Diana G; Peterson, Richard E; Bols, Niels C; Hodson, Peter V




EPA Science Inventory

Cyclopenta-fused PAH are a novel class of environmental PAH of which the most well known example is cyclopenta(cd)pyrene. The fusion of an unsaturated cyclopenta-ring on a PAH in general, markedly enhances its activity as a gene mutagen in bacteria and cultured mammalian cells, a...


PAH biodegradative genotypes in Lake Erie sediments: Evidence for broad geographical distribution of pyrene-degrading Mycobacteria  

Microsoft Academic Search

Despite a long history of anthropogenic contamination of Lake Erie sediments, little work has been done to understand the potential for PAH biodegradation by indigenous microbial communities. Pyrene-degrading Mycobacterium are prevalent in many polycyclic aromatic hydrocarbon (PAH)-contaminated freshwater sediments, and are of interest for their ability to degrade environmentally recalcitrant high molecular weight PAHs. This work tested the hypothesis that

Jennifer M. DeBruyn; Thomas J. Mead; Steven W. Wilhelm; Gary S. Sayler



Deciphering the roles of Arabidopsis LPCAT and PAH in phosphatidylcholine homeostasis and pathway coordination for chloroplast lipid synthesis.  


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. PMID:25268378

Wang, Liping; Kazachkov, Michael; Shen, Wenyun; Bai, Mei; Wu, Hong; Zou, Jitao




EPA Science Inventory

The PAHs in Blanks data set contains the analytical results for measurements of up to 26 polynuclear aromatic hydrocarbons (PAHs) in 27 blank samples of indoor air, outdoor air, and food. The PAHs of interest include Anthracene (CAS # 120-12-7), Benzo(ghi)pyrelene (CAS# 191-24-2...



EPA Science Inventory

This PAHs in Air data set contains 516 readings detecting the presence of polynuclear aromatic hydrocarbons (PAHs) in 86 households in the Arizona Border Study using a photo ionization device (PID). Keywords: air; PAHs, real time. The U.S.-Mexico Border Program is sponsored by...



EPA Science Inventory

The PAHs in Spikes data set contains the analytical results for measurements of up to 26 polynuclear aromatic hydrocarbons (PAHs) in 11 control samples (spikes) of indoor air and food over 8 households of PAHs concentrations in spike samples. Measurements were made in spiked sam...



EPA Science Inventory

Personal airborne exposures to carcinogenic particulate PAH have been significantly correlated with exposure to respirable fine particle mass (PM 2.5) in several studies. All combustion sources emit PAH, however the relative concentrations of different PAH and other organic tr...


Predicting PAH bioaccumulation and toxicity in earthworms exposed to manufactured gas plant soils with solid-phase microextraction  

Microsoft Academic Search

Soils from former manufactured gas plant (MGP) sites are often heavily contaminated with polycyclic aromatic hydrocarbons (PAHs). Current risk assessment methods that rely on total PAH concentrations likely overstate adverse effects of such soils since bioavailability is ignored. In this study, solid-phase microextraction (SPME) was applied to estimate bioavailable PAH concentrations and toxicity in earthworms exposed to 15 MGP soils.

Michiel T. O. Jonker; Stephan A. van der Heijden; Joseph P. Kreitinger; Steven B. Hawthorne



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


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 ?g 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. PMID:24595754

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



Rapid assessment of polycyclic aromatic hydrocarbon (PAH) exposure in decapod crustaceans by fluorimetric analysis of urine and haemolymph  

Microsoft Academic Search

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous and potentially harmful contaminants of the coastal and marine environment. Studies of their bioavailability, disposition and metabolism in marine organisms are therefore important for environmental monitoring purposes. Detecting PAH compounds in the biological fluids of marine organisms provides a measure of their environmental exposure to PAHs. In the present study, the shore crab Carcinus

Giles M Watson; Odd-Ketil Andersen; Tamara S Galloway; Michael H Depledge



Preliminary assessment of alkane and PAH data for sediment cores from six lakes in the Fraser River basin  

E-print Network

Preliminary assessment of alkane and PAH data for sediment cores from six lakes in the Fraser River including alkanes and polynuclear aromatic hydrocarbons (PAH). A preliminary examination of the data using detectable alkane and PAH compounds but there are differences between lakes and between sediment depths


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


The polycyclic aromatic hydrocarbon emissions in particulate and gas phases generated from smoldering mosquito coils containing various atomic H/C ratios were examined. Five types of mosquito coils were burned in a test chamber with a total airflow rate of 8.0L/min at a constant relative humidity and temperature. The concentrations of individual PAHs were determined using the GC/MS technique. Among the used mosquito coils, the atomic H/C ratio ranged from 1.23 to 1.57, yielding total mass, gaseous, and particulate PAH emission factors of 28.17-78.72mg/g, 26,139.80-35,932.98 and 5735.22-13,431.51ng/g, respectively. The various partitions of PAHs in the gaseous and particulate phases were in the ranges, 70.26-83.70% and 16.30-29.74% for the utilized mosquito coils. The carcinogenic potency of PAH emissions in the particulate phase (203.82-797.76ng/g) was approximately 6.92-25.08 times higher than that of the gaseous phase (26.27-36.07ng/g). Based on the analyses of PAH emissions, mosquito coils containing the lowest H/C ratio, a low oxygen level, and additional additives (i.e., CaCO3) are recommended for minimizing the production of total PAH emission factors and carcinogenic potency. PMID:25460974

Yang, Tzu-Ting; Lin, Shaw-Tao; Lin, Tser-Sheng; Chung, Hua-Yi



From Interstellar PAHs and Ices to the Origin of Life  

NASA Technical Reports Server (NTRS)

Tremendous strides have been made in our understanding of interstellar material over the past twenty years thanks to significant, parallel developments in observational astronomy and laboratory astrophysics. Twenty years ago the composition of interstellar dust was largely guessed at, the concept of ices in dense molecular clouds ignored, and the notion of large, abundant, gas phase, carbon rich molecules widespread throughout the interstellar medium (ISM) considered impossible. Today the composition of dust in the diffuse ISM is reasonably well constrained to micron-sized cold refractory materials comprised of amorphous and crystalline silicates mixed with an amorphous carbonaceous material containing aromatic structural units and short, branched aliphatic chains. In dense molecular clouds, the birthplace of stars and planets, these cold dust particles are coated with mixed molecular ices whose composition is very well constrained. Lastly, the signature of carbon-rich polycyclic aromatic hydrocarbons (PAHs), shockingly large molecules by earlier interstellar chemistry standards, is widespread throughout the Universe. The first part of this lecture will describe how infrared studies of interstellar space, combined with laboratory simulations, have revealed the composition of interstellar ices (the building blocks of comets) and the high abundance and nature of interstellar PAHs. The laboratory database has now enabled us to gain insight into the identities, concentrations, and physical state of many interstellar materials. Within a dense molecular cloud, and especially in the solar nebula during the star and planet formation stage, the materials frozen into interstellar/precometary ices are photoprocessed by ultraviolet light, producing more complex molecules. The remainder of the presentation will focus on the photochemical evolution of these materials and the possible role of these compounds on the early Earth. As these materials are thought to be the building blocks of comets and related to the carbonaceous components of micrometeorites, they are likely to have been important sources of complex organic materials on the early Earth and their composition may be related to the origin of life.

Allamandola, Louis J.; DeVincenzi, Donald L. (Technical Monitor)



The role of CYP1A inhibition in the embryotoxic interactions between hypoxia and polycyclic aromatic hydrocarbons (PAHs) and PAH mixtures in zebrafish (Danio rerio)  

PubMed Central

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants with elevated concentrations in waters that may also experience hypoxia. Previous research has shown interactions between hypoxia and some PAHs (fluoranthene, ?-naphthoflavone) but no interaction with others (benzo[a]pyrene (BaP), ?-naphthoflavone). Here we examine how hypoxia (7.4% oxygen, ~35% of normoxia) affects the embryotoxicity of PAHs that act through different mechanisms and the role that CYP1A inhibition may play in these interactions. 500 ?g/L BaP and 1-200 ?g/L benzo[k]fluoranthene (BkF) interacted synergistically with hypoxia to induce pericardial edema in developing zebrafish (Danio rerio). Hypoxia protected from the embryotoxicity of pyrene (PY) and had no effect on the toxicity of polychlorinated biphenyl-126. Despite previous reports of other CYP1A inhibitors interacting with hypoxia, up to 2000 ?g/L dibenzothiophene, 2-aminoanthracene (AA), and carbazole (CB) all failed to induce embryotoxicity under normoxic or hypoxic conditions. The toxicity of PAH mixtures—including binary mixtures of BaP/AA and BaP/CB and two environmentally relevant, complex mixtures—were exacerbated severely by hypoxia to induce or worsen pericardial edema and cause mortality. The interactions between hypoxia and BkF and PY were closely mimicked by morpholino knockdown of CYP1A, indicating a potential role for metabolism of these compounds in their toxicity. Our results indicate that various PAHs may exhibit synergistic, antagonistic or additive toxicity with hypoxia. The enhanced toxicity of environmental mixtures of PAHs under hypoxia suggests that risk assessments that do not take into account potential interactions with hypoxia may underestimate the threat of PAHs to fish in contaminated sites. PMID:21706407

Fleming, Carrie R.; Di Giulio, Richard T.



Investigation into the distribution of polycyclic aromatic hydrocarbons (PAHs) in wastewater sewage sludge and its resulting pyrolysis bio-oils.  


This study firstly investigated the distributions of 16 US EPA priority controlled polycyclic aromatic hydrocarbons (PAHs) in seven kinds of different wastewater sewage sludges and bio-oils from the sludge pyrolysis. A lab-scale tube furnace was used to simulate sludge pyrolysis and retrieve condensed oils. PAH determination was conducted with the extraction, concentration, and purification of PAHs in sludge samples and the resulting bio-oils, and then GC-MS analysis. Then, the factors influencing the distributions of different rings of PAHs in pyrolysis bio-oil, such as the chemical characteristics of raw sewage sludge and pyrolysis condition, were analyzed. It was noted that the total amount of PAHs in raw sludge is evidently varied with the sludge resource, with values ranging between 9.19 and 23.68 mg/kg. The middle molar weight (MMW) PAH distribution is dominant. PAH concentrations in sludge pyrolysis bio-oil were ranged from 13.72 to 48.9 mg/kg. The most abundant PAHs were the low molar weight (LMW) PAHs. It could be found that the concentration of LMW PAHs in bio-oil is correlated with MMW PAHs in raw sewage sludge at best, which the correlation coefficient is 0.607. For MMW and HMW (high molar weight) PAHs, they are significantly correlated with HMW PAHs in raw sewage sludge, which the correlation coefficients are 0.672 and 0.580, respectively. The concentration of LMW PAHs in bio-oil is also relatively significant and correlated with the volatile matter content of raw sludge. In addition, it was proved that final temperature and residence time have important influences on PAH generations during the pyrolysis of sewage sludge. PMID:24388824

Hu, Yanjun; Li, Guojian; Yan, Mi; Ping, Chuanjuan; Ren, Jianli



PAHs underfoot: Contaminated dust from coal-tar sealcoated pavement is widespread in the United States  

USGS Publications Warehouse

We reported in 2005 that runoff from parking lots treated with coal-tar-based sealcoat was a major source of polycyclic aromatic hydrocarbons (PAHs) to streams in Austin, Texas. Here we present new data from nine U. S. cities that show nationwide patterns in concentrations of PAHs associated with sealcoat Dust was swept from parking lots in six cities in the central and eastern U. S., where coal-tar-based sealcoat dominates use, and three cities in the western U. S., where asphalt-based sealcoat dominates use. For six central and eastern cities, median ?? PAH concentrations in dust from sealcoated and unsealcoated pavement are 2200 and 27 mg/kg, respectively. For three western cities, median ?? PAH concentrations in dust from sealcoated and unsealcoated pavement are similar and very low (2. 1 and 0. 8 mg/kg, respectively). Lakes in the central and eastern cities where pavement was sampled have bottom sediments with higher PAH concentrations than do those in the western cities relative to degree of urbanization. Bottom-sediment PAH assemblages are similar to those of sealcoated pavement dust regionally, implicating coal-tar-based sealcoat as a PAH source to the central and eastern lakes. Concentrations of benzo[a]pyrene in dust from coal-tar sealcoated pavement and adjacent soils greatly exceed generic soil screening levels, suggesting that research on human-health risk is warranted.

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



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


The concentrations of 27 polycyclic aromatic hydrocarbons (PAHs) were determined in bottom sediments and starfish from Mohang Harbor (MH) in Taean peninsula, South Korea. In December 2007, crude oil washed ashore from the M/V Hebei Spirit and was subsequently cleaned up within a few months of the incident. The ecological risk, bioaccumulation factor (BAF), and composition of the 27 PAHs were examined. The PAH concentrations in the bottom sediment ranged from 24 to 366 ?g/kg dried weight, and the ecological risk was determined as minimal (mERL-Q?PAH concentrations in Asterina pectinifera (inside seawall) and Asterias amurensis (outside seawall) were 1,226 and 1,477 ?g/kg dry weight (d.w.), respectively. The total BAFs (?BAF) for A. amurensis was 3.8 times higher than that of A. pectinifera, and the PAH concentrations of 5-6 log K OW were highest in the two starfish species. Further, PAH fingerprint analysis (nine alkyl-substituted PAHs fraction, low molecular weight (LMW)/high molecular weight (HMW), Phe/Ant, and Flu/Pyr), and principal component analysis (PCA) based on three crude oil samples from the M/V Hebei Spirit showed no remaining influence of crude oil. PMID:24682639

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



Particulate PAH emissions from residential biomass combustion: time-resolved analysis with aerosol mass spectrometry.  


Time-resolved emissions of particulate polycyclic aromatic hydrocarbons (PAHs) and total organic particulate matter (OA) from a wood log stove and an adjusted pellet stove were investigated with high-resolution time-of-flight aerosol mass spectrometry (AMS). The highest OA emissions were found during the addition of log wood on glowing embers, that is, slow burning pyrolysis conditions. These emissions contained about 1% PAHs (of OA). The highest PAH emissions were found during fast burning under hot air starved combustion conditions, in both stoves. In the latter case, PAHs contributed up to 40% of OA, likely due to thermal degradation of other condensable species. The distribution of PAHs was also shifted toward larger molecules in these emissions. AMS signals attributed to PAHs were found at molecular weights up to 600 Da. The vacuum aerodynamic size distribution was found to be bimodal with a smaller mode (Dva ? 200 nm) dominating under hot air starved combustion and a larger sized mode dominating under slow burning pyrolysis (Dva ? 600 nm). Simultaneous reduction of PAHs, OA and total particulate matter from residential biomass combustion may prove to be a challenge for environmental legislation efforts as these classes of emissions are elevated at different combustion conditions. PMID:24866381

Eriksson, A C; Nordin, E Z; Nyström, R; Pettersson, E; Swietlicki, E; Bergvall, C; Westerholm, R; Boman, C; Pagels, J H



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


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. PMID:24374215

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



Human mesenchymal stem cell osteoblast differentiation, ECM deposition, and biomineralization on PAH/PAA polyelectrolyte multilayers.  


Polyelectrolyte multilayer (PEMU) coatings built layer by layer with alternating pairs of polyelectrolytes can be tuned to improve cell interactions with surfaces and may be useful as biocompatible coatings to improve fixation between implants and tissues. Here, we show that human mesenchymal stromal cells (hMSCs) induced with bone differentiation medium (BDM) to become osteoblasts biomineralize crosslinked PEMUs built with the polycation poly(allylamine hydrochloride) (PAH) and the polyanion poly(acrylic acid) (PAA). Degrees of hMSC osteoblast differentiation and surface biomineralization on the smooth PAH-terminated PEMUs (PAH-PEMUs) and microstructured PAA-terminated PEMUs (PAA-PEMUs) reflect differences in cell-deposited extracellular matrix (ECM). BDM-induced hMSCs expressed higher levels of the early osteoblast differentiation marker alkaline phosphatase and collagen 1 (COL1) sooner on PAA-PEMUs than on PAH-PEMUs. Cells on both types of PEMUs proceeded to express the later stage osteoblast differentiation marker bone sialoprotein (BSP), but the BDM-induced cells organized a more amorphous Collagen I and denser BSP localization on PAA-PEMUs than on PAH-PEMUs. These ECM properties correlated with greater biomineralization on the PAA-PEMUs than on PAH-PEMUs. Together, these results confirm the suitability of PAH/PAA PEMUs as a substrate for hMSC osteogenesis and highlight the importance of substrate effects on ECM organization and BSP presentation on biomineralization. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2014. PMID:25203301

Pattabhi, Sudhakara Rao; Lehaf, Ali M; Schlenoff, Joseph B; Keller, Thomas C S



Infrared absorption and emission characteristics of interstellar PAHs (Polycyclic Aromatic Hydrocarbon)  

SciTech Connect

The mid-infrared interstellar emission spectrum with features at 3050, 1610, 1300, 1150, and 885 cm/sup -1/ (3.28, 6.2, 7.7, 8.7 and 11.3 microns) is discussed in terms of the Polycyclic Aromatic Hydrocarbon (PAH) hypothesis. This hypothesis is based on the suggestive, but inconclusive comparison between the interstellar emission spectrum with the infrared absorption and Raman spectra of a few PAHs. The fundamental vibrations of PAHs and PAH-like species which determine the ir and Raman properties are discussed. Interstellar ir band emission is due to relaxation from highly vibrationally excited PAHs which have been excited by ultraviolet photons. The excitation/emission process is described in general and the ir fluorescence from one PAH, chrysene, is traced in detail. Generally, there is sufficient energy to populate several vibrational levels in each mode. Molecular vibrational potentials are anharmonic and emission from these higher levels will fall at lower frequencies and produce weak features to the red of the stronger fundamentals. This process is also described and can account for some spectroscopic details of the interstellar emission spectra previously unexplained. Analysis of the interstellar spectrum shows that PAHs containing between 20 and 30 carbon atoms are responsible for the emission. 43 refs., 11 figs.

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



Emission of polycyclic aromatic hydrocarbons (PAHs) from the liquid injection incineration of petrochemical industrial wastewater.  


This study investigated the emission of polycyclic aromatic hydrocarbons (PAHs) from stack flue gas and air pollution control device (APCD) effluent of the liquid injection incinerator (LII) disposing the petrochemical industrial wastewater, and PAH removal efficiencies of wet electrostatic precipitator (WESP) and wet scrubber (WSB). The PAH carcinogenic potency were investigated with the benzo(a)pyrene equivalent concentration (BaP(eq)). The remarkably high total-BaP(eq) concentration (220 microgNm(-3)) in the stack flue gas was much higher than those of several published emission sources, and indicated the possible influence on its surrounding environment. The total-PAH emission factors of the WESP, WSB and stack flue gas were 78.9, 95.7 and 30,900 microgL(-1) wastewater, respectively. The removal efficiencies of total-PAHs were 0.254, 0.309 and 0.563% for WESP, WSB and overall, respectively, suggesting that the use of both WESP and WSB shows insignificant PAH removal efficiencies, and 99.4% of total-PAHs was directly emitted to the ambient air through the stack flue gas. This finding suggested that the better incineration efficiencies, and APCD removal efficiencies for disposing the petrochemical industrial wastewater are necessary in future. PMID:17368715

Wang, Lin-Chi; Wang, I-Ching; Chang, Juu-En; Lai, Soon-Onn; Chang-Chien, Guo-Ping



Role of CYP1B1 in PAH-DNA adduct formation and breast cancer risk  

SciTech Connect

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 result 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.

Goth-Goldstein, Regine; Russell, Marion L.; Muller, A.P.; Caleffi, M.; Eschiletti, J.; Graudenz, M.; Sohn, Michael D.



Tubule urate and PAH transport: sensitivity and specificity of serum protein inhibition  

SciTech Connect

Macromolecules in rabbit serum inhibit the cellular uptake and transepithelial secretion of (/sup 14/C)urate and p-(/sup 3/H)aminohippurate ((/sup 3/H)PAH) in rabbit S/sub 2/ proximal tubule segments. To understand better the potential role these inhibitors may have in the regulation of renal organic anion excretion, the authors examined the specificity and relative inhibitory effects on tubule urate and PAH transport of albumin and ..gamma..-globulin, the major inhibitory proteins in rabbit serum. Native rabbit serum markedly inhibited the cellular accumulation or urate and PAH by isolated nonperfused segments. Urate and PAH transport was also inhibited by bovine serum, human serum, Cohn-fractionated rabbit albumin, and rabbit ..gamma..-globulin, but not by Cohn-fractionated bovine serum albumin. ..cap alpha..-Lactalbumin and ..beta..-lactoglobulin, derived from milk, also inhibited urate and PAH transport, but to a lesser extent than albumin and ..gamma..-globulin. The transport inhibitory effects of proteins were independent of their binding to urate and PAH. Unidirectional influx and the steady-state intracellular accumulation of urate and PAH in suspensions of proximal tubules were decreased by rabbit serum proteins, suggesting that these inhibitors act on the external face of the cells to diminish the uptake of the organic anions. These studies indicate that the principal plasma proteins (albumin and ..gamma..-globulin) significantly inhibit urate and PAH transporters in the basolateral membranes of S/sub 2/ proximal tubules. They suggest that circulating plasma proteins that can penetrate the basement membrane of proximal tubules may directly modulate the renal excretion of urate and PAH.

Grantham, J.J.; Kennedy, J.; Cowley, B.



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

NASA Astrophysics Data System (ADS)

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, ?PAH 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 ?PAH 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.

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



Chronic dietary exposure of zebrafish to PAH mixtures results in carcinogenic but not genotoxic effects.  


Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants that can be present at high levels as mixtures in polluted aquatic environments. Many PAHs are potent mutagens and several are well-known carcinogens. Despite numerous studies on individual compounds, little is known about the toxicity of PAHs mixtures that are encountered in environmental situations. In the present work, zebrafish were continuously fed from 5 days post-fertilisation to 14 months post-fertilisation (mpf) with a diet spiked with fractions of either pyrolytic (PY), petrogenic light oil (LO), or petrogenic heavy oil (HO) origin at three concentrations. A decrease in survival was identified after 3 mpf in fish fed with the highest concentration of HO or LO, but not for PY. All PAH fractions caused preneoplastic and neoplastic disorders in long-term-exposed animals. Target tissues were almost exclusively of epithelial origin, with the bile duct epithelium being the most susceptible to chronic exposure to all PAH fractions, and with germ cells being the second most responsive cells. Significantly higher incidences of neoplasms were observed with increasing PAH concentration and exposure duration. The most severe carcinogenic effects were induced by dietary exposure to HO compared to exposure to LO or PY (45, 30 and 7 %, respectively, after 9 to 10 months of exposure to an intermediate concentration of PAHs). In contrast, earliest carcinogenic effects were detected as soon as 3 mpf after exposure to LO, including the lowest concentration, or to PY. PAH bioactivation and genotoxicity in blood was assessed by ethoxyresorufin-O-deethylase activity quantification and comet and micronuclei assays, respectively, but none of these were positive. Chronic dietary exposure of zebrafish to PAH mixtures results in carcinogenotoxic events that impair survival and physiology of exposed fish. PMID:24777325

Larcher, T; Perrichon, P; Vignet, C; Ledevin, M; Le Menach, K; Lyphout, L; Landi, L; Clerandeau, C; Lebihanic, F; Ménard, D; Burgeot, T; Budzinski, H; Akcha, F; Cachot, J; Cousin, X



Aquatic distribution and heterotrophic degradation of Polycyclic Aromatic Hydrocarbons (PAH) in the Tamar Estuary  

NASA Astrophysics Data System (ADS)

Variations in the concentrations and microheterotrophic degradation rates of selected Polycyclic Aromatic Hydrocarbons (PAH) in the water column of the Tamar Estuary were investigated in relation to the major environmental variables. Concentrations of individual PAH varied typically between i and 50 ng l -1 Based on their observed environmental behaviour the PAH appeared divisible into two groupings: (1) low molecular weight PAH incorporating naphthalene, phenanthrene and anthracence and (a) the larger molecular weight homologues (fluoranthene, pyrene, chrysene, benz(a)anthracene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)-pyrene). Group 1 PAH showed a complex distribution throughout the estuary with no significant correlations with either salinity or suspended particulates. Based on their relatively low particle affinity and high water solubilities and vapour pressures, volatilization is proposed as an important process in determining their fate. Microheterotrophic turnover times of naphthalene varied between x and 30 days, and were independent of suspended solids with maximum degradation rates located in the central and urban regions of the Estuary. When compared with the flushing times for the Tamar (3-5 days), it is probable that heterotrophic activity is important in the removal of naphthalene (and possibly the other Group 1 PAH) from the estuarine environment. In contrast Group 2 PAH concentrations exhibited highly significant correlations with suspended particulates. Highest concentrations occurred at the turbidity maximum, with a secondary concentration maximum localized to the industrialized portion of the estuary and associated with anthropogenic inputs. Laboratory degradation studies of benzo(a)pyrene in water samples taken from the estuary showed turnover times for the compound of between 2000 and 9000 days. Degradation rates correlated positively with suspended solids. The high particulate affinity and microbial refractivity of Group 2 PAH indicate sediment burial as the principal tate of these PAH in the Tamar Estuary. Estuarine sediments contained typically 50-1500 ng g -1 dry weight of individual PAH which were comparable to the levels of Group 2 PAH associated with the suspended particulates. Highest concentrations occurred at the riverine end of the estuary resulting from unresolved inputs in the catchment. Subsequent dilution by less polluted marine sediments together with slow degradation results in a seaward trend of decreasing concentrations. However, there is a secondary maximum of PAH superimposed on this trend which is associated with urban Plymouth.

Readman, J. W.; Mantoura, R. F. C.; Rhead, M. M.; Brown, L.



Adsorption of Polycyclic Aromatic Hydrocarbons (PAHS) from Aqueous Solutions on Different Sorbents  

NASA Astrophysics Data System (ADS)

This paper presents the results of the possibility and effectiveness of PAHs removal from a model aqueous solution, during the sorption on the selected sorbents. Six PAHs (naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene) listed by EPA for the analysis in the environmental samples were determined. Model aqueous solution was prepared with RESTEK 610 mix PAHs standard. After the sorption process, decrease in the concentration of individual hydrocarbons was observed. The removal percentage was dependent on the type of sorbent (quartz sand, mineral sorbent, activated carbon). The highest efficiency (98.1%) was observed for activated carbon.. The results shows that the sorption processes can be used in aqueous solutions