WorldWideScience

Sample records for rings pah components

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

    International Nuclear Information System (INIS)

    Lehndorff, E.; Schwark, L.

    2009-01-01

    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. - Accumulation of volatile three-ring PAHs on pine needles was found to be systematic over a period of 50 months thus qualifying PAHs for regional air quality studies

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

    Energy Technology Data Exchange (ETDEWEB)

    Lehndorff, E. [Department of Geology and Mineralogy, University of Cologne, Zuelpicher Str. 49a, 50674 Cologne (Germany); Schwark, L. [Department of Geology and Mineralogy, University of Cologne, Zuelpicher Str. 49a, 50674 Cologne (Germany); Institute of Geosciences, Kiel University, Ludewig-Meyn-Str. 10, 24118 Kiel (Germany)], E-mail: ls@gpi.uni-kiel.de

    2009-04-15

    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{sup 2} = 0.83 for phenanthrene and methylphenanthrenes, r{sup 2} = 0.77 for cyclopenta[def]phenanthrene, r{sup 2} = 0.60 for dibenzothiophene, r{sup 2} = 0.57 for dimethylphenanthrenes and r{sup 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. - Accumulation of volatile three-ring PAHs on pine needles was found to be systematic over a period of 50 months thus qualifying PAHs for regional air quality studies.

  3. Revisiting shape selectivity in liquid chromatography for polycyclic aromatic hydrocarbons (PAHs) - six-ring and seven-ring Cata-condensed PAH isomers of molecular mass 328 Da and 378 Da.

    Science.gov (United States)

    Oña-Ruales, Jorge O; Sander, Lane C; Wilson, Walter B; Wise, Stephen A

    2018-01-01

    The relationship of reversed-phase liquid chromatography (RPLC) retention on a polymeric C 18 stationary phase and the shape of polycyclic aromatic hydrocarbons (PAHs) was investigated for three-ring to seven-ring cata-condensed isomers. We report the first RPLC separation for six-ring and seven-ring cata-condensed PAH isomers. Correlations of LC retention and shape parameters (length-to-breath ratio, L/B and thickness, T) were investigated for 2 three-ring isomers (molecular mass 178 Da), 5 four-ring isomers (molecular mass 228 Da), 11 five-ring isomers (molecular mass 278 Da), 17 six-ring isomers (molecular mass 328 Da), and 20 seven-ring isomers (molecular mass 378 Da). Significant linear correlations were found for all isomer groups (r = 0.71 to 0.94). Nonplanarity of the PAH isomers was found to influence retention (i.e., nonplanar isomers eluting earlier than expected based on L/B) and linear correlations of retention vs. T for isomer groups containing nonplanar isomers were significant (r = 0.71 to 0.86). Graphical abstract.

  4. Effects of polycyclic aromatic hydrocarbons on microbial community structure and PAH ring hydroxylating dioxygenase gene abundance in soil.

    Science.gov (United States)

    Sawulski, Przemyslaw; Clipson, Nicholas; Doyle, Evelyn

    2014-11-01

    Development of successful bioremediation strategies for environments contaminated with recalcitrant pollutants requires in-depth knowledge of the microorganisms and microbial processes involved in degradation. The response of soil microbial communities to three polycyclic aromatic hydrocarbons, phenanthrene (3-ring), fluoranthene (4-ring) and benzo(a)pyrene (5-ring), was examined. Profiles of bacterial, archaeal and fungal communities were generated using molecular fingerprinting techniques (TRFLP, ARISA) and multivariate statistical tools were employed to interpret the effect of PAHs on community dynamics and composition. The extent and rate of PAH removal was directly related to the chemical structure, with the 5-ring PAH benzo(a)pyrene degraded more slowly than phenathrene or fluoranthene. Bacterial, archaeal and fungal communities were all significantly affected by PAH amendment, time and their interaction. Based on analysis of clone libraries, Actinobacteria appeared to dominate in fluoranthene amended soil, although they also represented a significant portion of the diversity in phenanthrene amended and unamended soils. In addition there appeared to be more γ-Proteobacteria and less Bacteroidetes in soil amended with either PAH compared to the control. The soil bacterial community clearly possessed the potential to degrade PAHs as evidenced by the abundance of PAH ring hydroxylating (PAH-RHDα) genes from both gram negative (GN) and gram positive (GP) bacteria in PAH-amended and control soils. Although the dioxygenase gene from GP bacteria was less abundant in soil than the gene associated with GN bacteria, significant (p PAH-RHDα gene were observed during phenanthrene and fluoranthene degradation, whereas there was no significant difference in the abundance of the GN PAH-RHDα gene during the course of the experiment. Few studies to-date have examined the effect of pollutants on more than one microbial community in soil. The current study provides

  5. A Resolved and Asymmetric Ring of PAHs within the Young Circumstellar Disk of IRS 48

    Energy Technology Data Exchange (ETDEWEB)

    Schworer, Guillaume; Lacour, Sylvestre; Du Foresto, Vincent Coudé [LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universits, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cité (France); Huélamo, Nuria [Dpto. Astrofísica, Centro de Astrobiología (INTA-CSIC), ESAC Campus, P.O. Box 78, E-28691, Villanueva de la Cañada (Spain); Pinte, Christophe; Chauvin, Gaël [Univ. Grenoble Alpes, IPAG, F-38000 Grenoble, France CNRS, IPAG, F-38000 Grenoble (France); Ehrenreich, David [Observatoire de l’Université de Genève, 51 chemin des Maillettes, 1290 Versoix (Switzerland); Girard, Julien [European Southern Observatory, Alonso de Cordova 3107, Casilla 19001 Vitacura, Santiago 19 (Chile); Tuthill, Peter [Sydney Institute for Astronomy, School of Physics, The University of Sydney, NSW 2006 (Australia)

    2017-06-20

    For one decade, the spectral type and age of the ρ Oph object IRS-48 were subject to debate and mystery. Modeling its disk with mid-infrared to millimeter observations led to various explanations to account for the complex intricacy of dust holes and gas-depleted regions. We present multi-epoch high-angular-resolution interferometric near-infrared data of spatially resolved emissions in the first 15 au of IRS-48, known to have very strong polycyclic aromatic hydrocarbon (PAH) emissions within this dust-depleted region. We make use of new Sparse-Aperture-Masking data to instruct a revised radiative-transfer model, where spectral energy distribution fluxes and interferometry are jointly fitted. Neutral and ionized PAH, very small grains (VSG), and classical silicates are incorporated into the model; new stellar parameters and extinction laws are explored. A bright (42 L {sub ⊙}) and hence large (2.5 R {sub ⊙}) central star with A {sub v} = 12.5 mag and R {sub v} = 6.5 requires less near-infrared excess: the inner-most disk at ≈1 au is incompatible with the interferometric data. The revised stellar parameters place this system on a 4 Myr evolutionary track, four times younger than the previous estimations, which is in better agreement with the surrounding ρ Oph region and disk-lifetime observations. The disk-structure solution converges to a classical-grain outer disk from 55 au combined with an unsettled and fully resolved VSG and PAH ring, between 11 and 26 au. We find two overluminosities in the PAH ring at color-temperatures consistent with the radiative transfer simulations; one follows a Keplerian circular orbit at 14 au. We show a depletion of a factor of ≈5 of classical dust grains up to 0.3 mm compared to very small particles: the IRS-48 disk is nearly void of dust grains in the first 55 au. A 3.5 M {sub Jup} planet on a 40 au orbit can qualitatively explain the new disk structure.

  6. [Concentrations and Component Profiles PAHs in Surface Soils and Wheat Grains from the Cornfields Close to the Steel Smelting Industry in Handan, Hebei Province].

    Science.gov (United States)

    Wu, Di; Wang, Yi-long; Liu, Wei-jian; Chen, Yuan-chen; Fu, Xiao-fang; Tao, Shu; Liu, Wen-xin

    2016-02-15

    In this study, paired surface soil and mature wheat grain samples were collected in the cornfields near the large Handan Steel Manufacturer; and the total concentrations and compositional profiles of the parent PAHs were measured, then the spatial distribution characteristics and correlation with total organic carbon fractions in soil were determined. Accordingly, a preliminary source identification was performed, and the association between PAHs in surface soil and wheat grain was briefly discussed. The median concentration of total PAHs in surface soils from the cornfields of Handan was 398.9 ng x g(-1) (ranged from 123.4 ng x g(-1) to 1626.4 ng x g(-1), where around 18% and 10% of all the studied soil samples were over the corresponding quality criteria for total PAHs and B [a] P in soils, respectively. The MMW and HMW species were the main components in the compositional profiles of surface soils. Based on the specific isomeric ratios of PAHs species, coal/biomass combustion and transportation fuel (tail gas) were the dominant mixed sources for the local PAHs emission. The fractions of surface soil TOC had significant positive correlations with the total PAHs and also with the individual components with different rings. In addition, the median concentration of total PAHs in wheat grains collected in the cornfields near the Handan Steel Manufacture was 27.0 ng x g(-1) (ranged from 19.0-34.0 ng x g(-1)). The levels in wheat grains were not high, and lower than the related hygienic standards of food proposed by EU and China. The LMW and MMW PAHs with 2 to 4 rings occupied a larger proportion, more than 84% of the total PAHs, which was largely different from the component profiles in surface soils. This situation suggested that the local sources of PAHs in wheat grains may originate not only from surface soil via root absorption and internal transportation, but also from ambient air through dry and wet deposition on the leaf surface (stoma).

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

    International Nuclear Information System (INIS)

    Lehndorff, E.; Schwark, L.

    2009-01-01

    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. - Regional high-resolution biomonitoring identified lignite combustion in power plants to dominate over urban traffic and other emission sources.

  8. A highly sensitive monoclonal antibody based biosensor for quantifying 3–5 ring polycyclic aromatic hydrocarbons (PAHs in aqueous environmental samples

    Directory of Open Access Journals (Sweden)

    Xin Li

    2016-03-01

    Full Text Available Immunoassays based on monoclonal antibodies (mAbs are highly sensitive for the detection of polycyclic aromatic hydrocarbons (PAHs and can be employed to determine concentrations in near real-time. A sensitive generic mAb against PAHs, named as 2G8, was developed by a three-step screening procedure. It exhibited nearly uniformly high sensitivity against 3-ring to 5-ring unsubstituted PAHs and their common environmental methylated PAHs, with IC50 values between 1.68 and 31 μg/L (ppb. 2G8 has been successfully applied on the KinExA Inline Biosensor system for quantifying 3–5 ring PAHs in aqueous environmental samples. PAHs were detected at a concentration as low as 0.2 μg/L. Furthermore, the analyses only required 10 min for each sample. To evaluate the accuracy of the 2G8-based biosensor, the total PAH concentrations in a series of environmental samples analyzed by biosensor and GC–MS were compared. In most cases, the results yielded a good correlation between methods. This indicates that generic antibody 2G8 based biosensor possesses significant promise for a low cost, rapid method for PAH determination in aqueous samples. Keywords: Monoclonal antibody, PAH, Pore water, Biosensor, Pyrene

  9. Components for the CERN LEP ring

    Energy Technology Data Exchange (ETDEWEB)

    1987-01-01

    One of the most important experimental setups at the LEP (Large Electron Positron Collider) ring is called OPAL (Omni Purpose Apparatus for LEP). Sulzer-Escher Wyss, Zurich, is to deliver the iron yoke, i.e. the mechanical part of one of the nine OPAL detectors. The contract for the yoke includes essentially the two side parts, each consisting of ten modules and two end caps, the middle part, four special modules and two supporting rings, as well as both the poles. The combined weight of all the supply items comes to some 2300 t. (Auth.).

  10. The Coagulant Type Influence on Removal Efficiency of 5- and 6-Ring Pahs During Water Coagulation Process

    Directory of Open Access Journals (Sweden)

    Nowacka Anna

    2014-12-01

    Full Text Available The article presents results on investigation of the removal efficiency of selected 5- and 6-ring polycyclic aromatic hydrocarbons (benzo[a]pyrene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[j]fluoranthene, benzo[g,h,i]perylene, indeno[1,2,3-cd]pyrene, dibenzo[a,h]anthracene from water during coagulation and sedimentation process. Two pre-hydrolyzed aluminum coagulants: PAX XL 19H and FLOKOR 105V were chosen for research. Process was carried out at optimum process parameters: rapid-mixing - 3 min at the rotational speed of 200 rpm, slow mixing - 10 min at 30 rpm, sedimentation - 60 min. The removal effectiveness was dependant on coagulant type and its composition. Better results in the removal of 5-and 6-ring PAHs were obtained after application of FLOKOR 105V (lower aluminum content than after using PAX XL 19H.

  11. The effects of LMWOAs on biodegradation of multi-component PAHs in aqueous solution using dual-wavelength fluorimetry

    International Nuclear Information System (INIS)

    Wei Xingyuan; Sang Lingzi; Chen Jianing; Zhu Yaxian; Zhang Yong

    2009-01-01

    Biodegradation of dissolved fluorene (Flu), phenanthrene (Ph) and pyrene (Py), three polycyclic aromatic hydrocarbons (PAHs), singly or as a mixture of the three, by two bacterial strains, MEBIC 5140 (Mycobacterium flavescens) and MEBIC 5141 (Mycobacterium scrofulaceum), as well as the effects of low molecular weight organic acids (LMWOAs), e.g. malic acid, citric acid and butyric acid on biodegradation of the three PAHs in mineral salts medium aqueous solution were investigated using a newly established dual-wavelength fluorimetric method. The results showed that biodegradation processes can be monitored simultaneously, quickly and simply by dual-wavelength fluorimetry. Both co-metabolism and inhibitory effects were found during the biodegradation of the three PAHs by MEBIC 5140 and MEBIC 5141. Positive effects of butyric acid and negative effects of citric acid on biodegradation of the three PAHs in a mixture were observed. - Biodegradation processes of dissolved multi-component PAHs in a mixture and effects of LMWOAs were investigated using a dual-wavelength fluorimetry.

  12. Analysis of polycyclic aromatic hydrocarbons in tree-rings of Masson pine (Pinus massoniana L.) from two industrial sites in the Pearl River Delta, south China.

    Science.gov (United States)

    Kuang, Yuan-wen; Zhou, Guo-yi; Wen, Da-zhi; Li, Jiong; Sun, Fang-fang

    2011-09-01

    Concentrations of polycyclic aromatic hydrocarbons (PAHs) were examined and potential sources of PAHs were identified from the dated tree-rings of Masson pine (Pinus massoniana L.) near two industrial sites (Danshuikeng, DSK and Xiqiaoshan, XQS) in the Pearl River Delta of south China. Total concentrations of PAHs (∑PAHs) were revealed with similar patterns of temporal trends in the tree-rings at both sites, suggesting tree-rings recorded the historical variation in atmospheric PAHs. The differences of individual PAHs and of ∑PAHs detected in the tree-rings between the two sites reflected the historical differences of airborne PAHs. Regional changes in industrial activities might contribute to the site-specific and period-specific patterns of the tree-ring PAHs. The diagnostic PAH ratios of Ant/(Ant + PA), FL/(FL + Pyr), and BaA/(BaA + Chr)) revealed that PAHs in the tree-rings at both sites mainly stemmed from the combustion process (pyrogenic sources). Principal component analysis further confirmed that wood burning, coal combustion, diesel, and gasoline-powered vehicular emissions were the dominant contributors of PAHs sources at DSK, while diesel combustion, gasoline and natural gas combustion, and incomplete coal combustion were responsible for the main origins of PAHs at XQS. Tree-ring analysis of PAHs was indicative of PAHs from a mixture of sources of combustion, thus minimizing the bias of short-term active air sampling.

  13. Isolation and Characterization of Three and Four Ring Pahs Degrading Bacteria from Contaminated Sites, Ankleshwar, Gujarat, India

    Directory of Open Access Journals (Sweden)

    Jignasha G. Patel

    2015-02-01

    Full Text Available Polycyclic aromatic hydrocarbon (PAH-degrading bacteria were isolated from prolong contaminated Amalakhadi sediment and crude oil polluted soil Telva, near Ankleshwar Gujarat India. Organisms were treated with two-model PAHs compound Anthracene (ANT, and Pyrene (PYR as the sole source of carbon and energy. Identification of the isolates was carried out based on their morphological and partial 16S rRNA gene sequences, which revealed that the isolates belong to two main bacterial groups: gram-negative pseudomonas indoxyladons and gram-positive, spore-forming group, Bacillus benzoevorans. GC-MS based degradation study demonstrated that P. indoxyladons efficiently degrade 98% of ANT and PYR by 93.2 % when treated with 250 mg L-1. However, B. benzoevorans could tolerate to 200 mg L-1of PYR. Thus, the findings of the study provide novel bacterial sp. having different capacity to degrade model PAHs compounds and further could be utilized for the standardization of bioremediation protocols for ex situ and in situ studies in aquatic as well as terrestrial ecosystem.DOI: http://dx.doi.org/10.3126/ije.v4i1.12184International Journal of Environment Volume-4, Issue-1, Dec-Feb 2014/15, Page: 130-140  

  14. Effect of water flux and sediment discharge of the Yangtze River on PAHs sedimentation in the estuary.

    Science.gov (United States)

    Li, Rufeng; Feng, Chenghong; Wang, Dongxin; He, Maozhi; Hu, Lijuan; Shen, Zhenyao

    2016-12-01

    Historical distribution characteristics of polycyclic aromatic hydrocarbons (PAHs) and their carriers (i.e., organic matter and mineral particles) in the sediment cores of the Yangtze Estuary were investigated, with emphasis laid on the role of the Yangtze River. Grain size component of sediments (clay, silt, and sand) and organic carbon (black carbon and total organic carbon) in the sediment cores were markedly affected by water flux and sediment discharge of the Yangtze River. Qualitative and quantitative analysis results showed that sands and black carbon acted as the main carriers of PAHs. The sedimentation of two-ring to three-ring PAHs in the estuary had significant correlations with water flux and sediment discharge of the Yangtze River. The relative lower level of the four-ring and five-ring to six-ring PAHs concentrations appeared around the year 2003 and remained for the following several years. This time period accorded well with the water impoundment time of the Three Gorges Reservoir. The decreased level of two-ring to three-ring PAHs occurred in the year 1994, and the peak points around the year 2009 indicated that PAHs sedimentation in the estuary also had close relationship to severe drought and flood in the catchments. The findings presented in this paper could provide references for assessing the impacts of water flux and sediment discharge on the historical deposition of PAHs and their carriers in the Yangtze Estuary.

  15. Separation of electron ion ring components (computational simulation and experimental results)

    International Nuclear Information System (INIS)

    Aleksandrov, V.S.; Dolbilov, G.V.; Kazarinov, N.Yu.; Mironov, V.I.; Novikov, V.G.; Perel'shtejn, Eh.A.; Sarantsev, V.P.; Shevtsov, V.F.

    1978-01-01

    The problems of the available polarization value of electron-ion rings in the regime of acceleration and separation of its components at the final stage of acceleration are studied. The results of computational simulation by use of the macroparticle method and experiments on the ring acceleration and separation are given. The comparison of calculation results with experiment is presented

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

    Science.gov (United States)

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

    2015-10-01

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

  17. Structure and assembly of the essential RNA ring component of a viral DNA packaging motor.

    Science.gov (United States)

    Ding, Fang; Lu, Changrui; Zhao, Wei; Rajashankar, Kanagalaghatta R; Anderson, Dwight L; Jardine, Paul J; Grimes, Shelley; Ke, Ailong

    2011-05-03

    Prohead RNA (pRNA) is an essential component in the assembly and operation of the powerful bacteriophage 29 DNA packaging motor. The pRNA forms a multimeric ring via intermolecular base-pairing interactions between protomers that serves to guide the assembly of the ring ATPase that drives DNA packaging. Here we report the quaternary structure of this rare multimeric RNA at 3.5 Å resolution, crystallized as tetrameric rings. Strong quaternary interactions and the inherent flexibility helped rationalize how free pRNA is able to adopt multiple oligomerization states in solution. These characteristics also allowed excellent fitting of the crystallographic pRNA protomers into previous prohead/pRNA cryo-EM reconstructions, supporting the presence of a pentameric, but not hexameric, pRNA ring in the context of the DNA packaging motor. The pentameric pRNA ring anchors itself directly to the phage prohead by interacting specifically with the fivefold symmetric capsid structures that surround the head-tail connector portal. From these contacts, five RNA superhelices project from the pRNA ring, where they serve as scaffolds for binding and assembly of the ring ATPase, and possibly mediate communication between motor components. Construction of structure-based designer pRNAs with little sequence similarity to the wild-type pRNA were shown to fully support the packaging of 29 DNA.

  18. Morphological survey of bar, lens, and ring components in galaxies: Secular evolution in galaxy structure

    International Nuclear Information System (INIS)

    Kormendy, J.

    1979-01-01

    A morphological survey of barred galaxies is made to investigate the frequency of occurrence, nature, and size distributions of bars, lenses, inner and outer rings, and global spiral structure. The 121 brightest available barred galaxies are examined on Sky Survey copy plates, and on deeper and larger-scale plates, with the following main results.1. Lenses and inner rings are components of major importance in barred galaxies, occurring, respectively, in 54% of SBO--SBa, and 76% of SBab--SBc galaxies. Few early-type galaxies have rings; almost no late-type ones have lenses.2. There is an intimate connection between bars and lenses: in 17 of 20 galaxies with both components, the bar exactly fills the lens in one dimension.3. We suggest that lenses originate as bars, through an unknown process which makes some bars evolve away to a nearly axisymmetric state. Several properties of the proposed process are deduced. We emphasize the possible importance of internal processes of secular evolution in galaxy structure.4. Several galaxies, notably NGC 3945, seem to have strongly triaxial bulge components.5. Inner rings are round. Lenses tend to be slightly triaxial, flattened ellipsoids, with a preferred equatorial axis ratio of approx.0.9 +- 0.05. Most outer rings are prolate, the shortest dimension being the one filled by the bar.6. The sizes of bars, rings, and lenses are well correlated with the absolute magnitude of the galaxy, such that the mean surface brightness is constant for each morphological type. The form of the correlation M/sub B/+5 log D= constant is such that these diameters cannot be used as distance indicators. We show that the galaxy mass determines the bar size uniquely.7. Spiral structure in SB galaxies is distorted to resemble inner and outer rings, showing that the arms feel the potential of the bar. Also, of 61 survey galaxies with spiral structure, 55 have global patterns usually interpreted as density waves

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

    Science.gov (United States)

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

    2017-10-14

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

  20. Clinicopathologic and Molecular Features of Colorectal Adenocarcinoma with Signet-Ring Cell Component.

    Directory of Open Access Journals (Sweden)

    Qing Wei

    Full Text Available We performed a retrospective study to assess the clinicopathological characters, molecular alterations and multigene mutation profiles in colorectal cancer patients with signet-ring cell component.Between November 2008 and January 2015, 61 consecutive primary colorectal carcinomas with signet-ring cell component were available for pathological confirmation. RAS/BRAF status was performed by direct sequencing. 14 genes associated with hereditary cancer syndromes were analyzed by targeted gene sequencing.A slight male predominance was detected in these patients (59.0%. Colorectal carcinomas with signet-ring cell component were well distributed along the large intestine. A frequently higher TNM stage at the time of diagnosis was observed, compared with the conventional adenocarcinoma. Family history of malignant tumor was remarkable with 49.2% in 61 cases. The median OS time of stage IV patients in our study was 14 months. RAS mutations were detected in 22.2% (12/54 cases with KRAS mutations in 16.7% (9/54 cases and Nras mutations in 5.4%(3/54 cases. BRAF V600E mutation was detected in 3.7% (2/54 cases. As an exploration, we analyzed 14 genes by targeted gene sequencing. These genes were selected based on their biological role in association with hereditary cancer syndromes. 79.6% cases carried at least one pathogenic mutation. Finally, the patients were classified by the percentage of signet-ring cell. 39 (63.9% cases were composed of ≥50% signet-ring cells; 22 (36.1% cases were composed of <50% signet-ring cells. We compared clinical parameters, molecular and genetic alterations between the two groups and found no significant differences.Colorectal adenocarcinoma with signet-ring cell component is characterized by advanced stage at diagnosis with remarkable family history of malignant tumor. It is likely a negative prognostic factor and tends to affect male patients with low rates of RAS /BRAF mutation. Colorectal patients with any component of

  1. Change of PAHs with evolution of paddy soils from prehistoric to present over the last six millennia in the Yangtze River Delta region, China

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jin [School of Environmental and Resource Sciences, Zhejiang Agricultural and Forestry University, 88 North Huancheng Rd. of Lin' an, Hangzhou 311300 (China); Institute of Geosciences, Christian-Albrechts-University of Kiel, Ludewig-Meyn-Str. 10, 24118 Kiel (Germany); Cornelia, Mueller-Niggemann [Institute of Geosciences, Christian-Albrechts-University of Kiel, Ludewig-Meyn-Str. 10, 24118 Kiel (Germany); Wang, Minyan, E-mail: jz.zafu@gmail.com [Tianmu College of Zhejiang Agricultural and Forestry University, 252 Yijin Str.of Lin' an, Hangzhou 311300 (China); Cao, Zhihong [Institute of Soil Science, Chinese Academy of Sciences, 71 East Beijing Rd., Nanjing 210008 (China); Luo, Xiping, E-mail: luoxpzj@yahoo.com.cn [School of Environmental and Resource Sciences, Zhejiang Agricultural and Forestry University, 88 North Huancheng Rd. of Lin' an, Hangzhou 311300 (China); Wong, Minghung [School of Environmental and Resource Sciences, Zhejiang Agricultural and Forestry University, 88 North Huancheng Rd. of Lin' an, Hangzhou 311300 (China); Croucher Institute for Environmental Sciences, and Department of Biology, Hong Kong Baptist University, 224 Waterloo Rd., Kln., Hong Kong (China); Chen, Wei [Department of Ecology and Evolution, Frankfurt University, Max-Von-Laue Str. 13, 60438 Frankfurt am Main (Germany)

    2013-04-01

    To evaluate the influence of hydroponics management on soil organic components with evolution of paddy soil over the last six millennia, PAHs, as a biomarker, as well as total organic carbon content were used to explore changes of paddy soil organic carbon in two entirely buried ancient paddy soil profiles. The results showed that hydroponics management can cause organic carbon deposition in rice paddy. The changing of total PAH concentrations was not always in accordance with the changing of total organic carbon contents in layers of the buried ancient paddy soils. The PAHs in 6280 BP prehistoric paddy soil layer was 3-ring > 5-ring > 4-ring > 6-ring, while in layers of the present paddy soil and the prehistoric upland were 3-ring > 4-ring > 5-ring > 6-ring. The contribution of phenanthrene to total PAHs in two profiles and the increasing ratio of phenanthrene to alkylated PAHs from parent material/6280 BP prehistoric upland to 6280 BP paddy suggested substantial increase of the anthropogenic influence of hydroponics management on rice paddy soil. And in view of the {sup 14}C age and bioremains in the two profiles, it was only possible for PAHs to be derived from hydroponics management with evolution of the paddy soils form the Neolithic age. Cadalene could be used as an indicator for biological sources of PAHs released by rice plant residues, and benzo[g,h,i]fluoranthene and benzo[g,h,i]perylene for pyrogenic sources released by field vegetation fires. - Highlights: ► Soil hydroponics management can cause SOC deposition in rice paddy. ► PAHs in buried ancient paddy soil profiles were mainly derived from anthropogenic hydroponics management. ► PAH, as a biomarker, was not suitable for tracing SOC change with evolution of paddy soil from the Neolithic age.

  2. Change of PAHs with evolution of paddy soils from prehistoric to present over the last six millennia in the Yangtze River Delta region, China

    International Nuclear Information System (INIS)

    Zhang, Jin; Cornelia, Mueller-Niggemann; Wang, Minyan; Cao, Zhihong; Luo, Xiping; Wong, Minghung; Chen, Wei

    2013-01-01

    To evaluate the influence of hydroponics management on soil organic components with evolution of paddy soil over the last six millennia, PAHs, as a biomarker, as well as total organic carbon content were used to explore changes of paddy soil organic carbon in two entirely buried ancient paddy soil profiles. The results showed that hydroponics management can cause organic carbon deposition in rice paddy. The changing of total PAH concentrations was not always in accordance with the changing of total organic carbon contents in layers of the buried ancient paddy soils. The PAHs in 6280 BP prehistoric paddy soil layer was 3-ring > 5-ring > 4-ring > 6-ring, while in layers of the present paddy soil and the prehistoric upland were 3-ring > 4-ring > 5-ring > 6-ring. The contribution of phenanthrene to total PAHs in two profiles and the increasing ratio of phenanthrene to alkylated PAHs from parent material/6280 BP prehistoric upland to 6280 BP paddy suggested substantial increase of the anthropogenic influence of hydroponics management on rice paddy soil. And in view of the 14 C age and bioremains in the two profiles, it was only possible for PAHs to be derived from hydroponics management with evolution of the paddy soils form the Neolithic age. Cadalene could be used as an indicator for biological sources of PAHs released by rice plant residues, and benzo[g,h,i]fluoranthene and benzo[g,h,i]perylene for pyrogenic sources released by field vegetation fires. - Highlights: ► Soil hydroponics management can cause SOC deposition in rice paddy. ► PAHs in buried ancient paddy soil profiles were mainly derived from anthropogenic hydroponics management. ► PAH, as a biomarker, was not suitable for tracing SOC change with evolution of paddy soil from the Neolithic age

  3. Component and system tests of the SLD Cerenkov Ring Imaging Detector

    International Nuclear Information System (INIS)

    Antilogus, P.; Bird, F.; Aston, D.; Dasu, S.; Dunwoodie, W.; Hallewell, G.; Kawahara, H.; Kwon, Y.; Leith, D.; Nagamine, T.; Pavel, T.; Muller, D.; Williams, S.; Bienz, T.; Dolinsky, S.; Solodov, E.; Coyle, P.; Cavalli-Sforza, M.; Coyne, D.; Gagnon, P.; Liu, X.; Williams, D.A.

    1990-01-01

    The components of the SLD barrel Cerenkov Ring Imaging Detector (CRID) are now built and are being installed. This paper reports on tests of these components, including tests of the fiber optic calibration system, detailed studies of electron drift paths on production drift boxes and detectors, tests of the dynamic gating system and its effect on drift path distortions due to space-charge, and a measurement of the electron lifetime in a production drift box. In addition, the authors report on the UV transmission of recirculated liquid freon and on the effects of CRID construction materials on electron lifetime

  4. Component and system tests of the SLD Cerenkov Ring Imaging Detector

    International Nuclear Information System (INIS)

    Antilogus, P.; Aston, D.; Bienz, T.; Bird, F.; Dasu, S.; Dolinsky, S.; Dunwoodie, W.; Hallewell, G.; Kawahara, H.; Kwon, Y.; Leith, D.; Muller, D.; Nagamine, T.; Pavel, T.; Ratcliff, B.; Rensing, P.; Schultz, D.; Shapiro, S.; Simopoulos, C.; Solodov, E.; Toge, N.; Va'vra, J.; Williams, S.; Cavalli-Sforza, M.; Coyle, P.; Coyne, D.; Gagnon, P.; Liu, X.; Williams, D.A.; Whitaker, J.S.; Wilson, R.J.; Bean, A.; Caldwell, D.; Duboscq, J.; Huber, J.; Lu, A.; Mathys, L.; McHugh, S.; Witherell, M.; Yellin, S.; d'Oliveira, A.; Johnson, R.A.; Martinez, J.; Meadows, B.; Nussbaum, M.; Santha, A.K.S.; Shoup, A.; Stockdale, I.; Jacques, P.; Kalelkar, M.; Plano, R.; Stamer, P.; Abe, K.; Hasegawa, K.; Suekane, F.; Yuta, H.

    1990-10-01

    The components of the SLD barrel Cerenkov Ring Imaging Detector (CRID) are now built and are being installed. We report on tests of these components, including tests of the fiber optic calibration system, detailed studies of electron drift paths on production drift boxes and detectors, tests of the dynamic gating systems and its effect on drift path distortions due to space-charge, and a measurement of the electron lifetime in a production drift box. In addition, we report on the UV transmission of recirculated liquid freon and on the effects of CRID construction materials on electron lifetime. 16 refs., 12 figs

  5. Polycyclic aromatic hydrocarbons (PAHs in indoor dusts of Guizhou, southwest of China: status, sources and potential human health risk.

    Directory of Open Access Journals (Sweden)

    Qin Yang

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

  6. Component and system tests of the SLD Cerenkov Ring Imaging Detector

    International Nuclear Information System (INIS)

    Antilogus, P.; Aston, D.; Bienz, T.; Bird, F.; Dasu, S.; Dolinsky, S.; Dunwoodie, W.; Hallewell, G.; Kawahara, H.; Kwon, Y.; Leith, D.; Muller, D.; Nagamine, T.; Pavel, T.; Ratcliff, B.; Rensing, P.; Schultz, D.; Shapiro, S.; Simopoulos, C.; Solodov, E.; Toge, N.; Va'vra, J.; Williams, S.; Cavalli-Sforza, M.; Coyle, P.; Coyne, D.; Gagnon, P.; Liu, X.; Williams, D.A.; Whitaker, J.S.; Wilson, R.J.; Bean, A.; Caldwell, D.; Duboscq, J.; Huber, J.; Lu, A.; Mathys, L.; McHugh, S.; Witherell, M.; Yellin, S.; D'Oliveira, A.; Johnson, R.A.; Martinez, J.L.; Meadows, B.; Nussbaum, M.; Santha, A.K.S.; Shoup, A.; Stockdale, I.; Baird, K.; Jacques, P.; Kalelkar, M.; Plano, R.; Stamer, P.; Word, G.; Abe, K.; Hasegawa, K.; Suekane, F.; Yuta, H.

    1991-02-01

    The components of the SLD barrel Cerenkov Ring Imaging Detector (CRID) are now built and are being installed. We report on tests of these, including tests of the fiber optic calibration system, detailed studies of electron drift paths on production drift boxes and detectors, tests of the dynamic gating system and its effect on drift path distortions due to space-charge, and a measurement of the electron lifetime in a production drift box. In addition, we report on the UV transmission of recirculated liquid C 6 F 14 and on the effects of CRID construction materials on electron lifetime. 9 refs., 11 figs

  7. Accessory components in gas-lubricated floating ring seals; Zusatzeinrichtungen an gasgeschmierten Gleitringdichtungen

    Energy Technology Data Exchange (ETDEWEB)

    Kirchner, C.; Victor, K.H.

    1995-12-31

    The present paper uses existing designs of floating-ring seal systems to illustrate their use as accessory components in gas-lubricated axial-face seals. These floating-ring seals may be used as pre-seals on the side of the axial-face seal facing the product. Here they are subject to high ambient pressure and small pressure differences. On the side of the axial-face seal facing the sliding bearing they are used as post-seals, where they are subject to atmospheric conditions and small pressure differences. The authors present various purpose-specific designs of these seal systems. Theoretical calculation models are compared with measuring results obtained under conditions close to actual practice. (orig.) [Deutsch] Anhand von ausgefuehrten Konstruktionen werden Schwimmring-Dichtungssysteme als Zusatzeinrichtung an gasgeschmierten Gleitringdichtungen (GLRD) erlaeutert. Auf der produktzugewandten Seite der GLRD werden diese Schwimmringdichtungen als Vordichtung (Pre-Seal) eingesetzt, die bei hohen Umgebungsdruecken und geringen Druckdifferenzen betrieben werden. Auf der dem Gleitlager zugewandten Seite der GLRD werden Schwimmringdichtungen bei atmosphaerischen Bedingungen und ebenfalls geringen Druckdifferenzen als nachgeschaltete Dichtung (Post-Seal) eingesetzt. Es werden konstruktive Loesungen fuer die verschiedenen Aufgaben dieser Dichtungssysteme vorgestellt. Theoretische Berechnungsmodelle werden mit praxisnahen Messergebnissen verglichen. (orig.)

  8. Independent component analysis applied to long bunch beams in the Los Alamos Proton Storage Ring

    Science.gov (United States)

    Kolski, Jeffrey S.; Macek, Robert J.; McCrady, Rodney C.; Pang, Xiaoying

    2012-11-01

    Independent component analysis (ICA) is a powerful blind source separation (BSS) method. Compared to the typical BSS method, principal component analysis, ICA is more robust to noise, coupling, and nonlinearity. The conventional ICA application to turn-by-turn position data from multiple beam position monitors (BPMs) yields information about cross-BPM correlations. With this scheme, multi-BPM ICA has been used to measure the transverse betatron phase and amplitude functions, dispersion function, linear coupling, sextupole strength, and nonlinear beam dynamics. We apply ICA in a new way to slices along the bunch revealing correlations of particle motion within the beam bunch. We digitize beam signals of the long bunch at the Los Alamos Proton Storage Ring with a single device (BPM or fast current monitor) for an entire injection-extraction cycle. ICA of the digitized beam signals results in source signals, which we identify to describe varying betatron motion along the bunch, locations of transverse resonances along the bunch, measurement noise, characteristic frequencies of the digitizing oscilloscopes, and longitudinal beam structure.

  9. Independent component analysis applied to long bunch beams in the Los Alamos Proton Storage Ring

    Directory of Open Access Journals (Sweden)

    Jeffrey S. Kolski

    2012-11-01

    Full Text Available Independent component analysis (ICA is a powerful blind source separation (BSS method. Compared to the typical BSS method, principal component analysis, ICA is more robust to noise, coupling, and nonlinearity. The conventional ICA application to turn-by-turn position data from multiple beam position monitors (BPMs yields information about cross-BPM correlations. With this scheme, multi-BPM ICA has been used to measure the transverse betatron phase and amplitude functions, dispersion function, linear coupling, sextupole strength, and nonlinear beam dynamics. We apply ICA in a new way to slices along the bunch revealing correlations of particle motion within the beam bunch. We digitize beam signals of the long bunch at the Los Alamos Proton Storage Ring with a single device (BPM or fast current monitor for an entire injection-extraction cycle. ICA of the digitized beam signals results in source signals, which we identify to describe varying betatron motion along the bunch, locations of transverse resonances along the bunch, measurement noise, characteristic frequencies of the digitizing oscilloscopes, and longitudinal beam structure.

  10. Identification of prenatal toxic components of complex PAH mixtures derived from fossil fuel combustion employing rodent embryo culture systems

    International Nuclear Information System (INIS)

    Irvin, T.R.; Akgerman, A.

    1991-01-01

    Many adverse health effects caused by combustion-generated toxins have been recognized for some time. Acute pulmonary toxicity among urban populations has been repeatedly recorded during periods of high smoke, soot, and organo-particulate pollution. The combustion of coals and petroleum-derived fuels results in emission of particulate and organic vapor-phase components to the atmosphere. Isolation of these particle-absorbed compounds and subsequent toxicological testing has further indicated the importance of chronic, low-level exposure to airborne combustion-generated toxins in the etiology of many forms of human cancer; particulate phases of these emissions have been found to contain polycyclic aromatic hydrocarbons and heterocyclic organic compounds, absorbed onto the particle matrix, which possess potent carcinogenic and mutagenic properties. In this paper, the authors define a postimplantation rat embryo culture system constructed to identify prenatal toxic components of complex polycyclic aromatic hydrocarbon soots. Employing this culture system, we also describe its application to identify prenatal toxic components of diesel soot particulates

  11. PAHs and the Diffuse Interstellar Bands. What have we Learned from the New Generation of Laboratory and Observational Studies?

    Science.gov (United States)

    Salama, Farid

    2005-01-01

    Polycyclic Aromatic Hydrocarbons (PAHs) are an important and ubiquitous component of carbon-bearing materials in space. PAHs are the best-known candidates to account for the IR emission bands (UIR bands) and PAH spectral features are now being used as new probes of the ISM. PAHs are also thought to be among the carriers of the diffuse interstellar absorption bands (DIBs). In the model dealing with the interstellar spectral features, PAHs are present as a mixture of radicals, ions and neutral species. PAH ionization states reflect the ionization balance of the medium while PAH size, composition, and structure reflect the energetic and chemical history of the medium. A major challenge for laboratory astrophysics is to reproduce (in a realistic way) the physical conditions that exist in the emission and/or absorption interstellar zones, An extensive laboratory program has been developed at NASA Ames to characterize the physical and chemical properties of PAHs in astrophysical environments and to describe how they influence the radiation and energy balance in space and the interstellar chemistry. In particular, laboratory experiments provide measurements of the spectral characteristics of interstellar PAH analogs from the ultraviolet and visible range to the infrared range for comparison with astronomical data. This paper will focus on the recent progress made in the laboratory to measure the direct absorption spectra of neutral and ionized PAHs in the gas phase in the near-W and visible range in astrophysically relevant environments. These measurements provide data on PAHs and nanometer-sized particles that can now be directly compared to astronomical observations. The harsh physical conditions of the IS medium - characterized by a low temperature, an absence of collisions and strong V W radiation fields - are simulated in the laboratory by associating a molecular beam with an ionizing discharge to generate a cold plasma expansion. PAH ions are formed from the neutral

  12. The design of the optical components and gas control systems of the CERN Omega Ring Imaging Cerenkov Detector

    International Nuclear Information System (INIS)

    Apsimon, R.J.; Cowell, J.; Flower, P.S.

    1985-06-01

    A large Ring Imaging Cerenkov Detector (RICH) has been commissioned for use at the CERN Omega Spectrometer. The general design of the device is discussed, and the dependence of the attainable spatial resolution and range of particle identification on its optical parameters is illustrated. The construction and performance of the major optical components and gas systems of the detector are also described. (author)

  13. Comparison of techniques for estimating PAH bioavailability: Uptake in Eisenia fetida, passive samplers and leaching using various solvents and additives

    Energy Technology Data Exchange (ETDEWEB)

    Bergknut, Magnus [Department of Chemistry, Environmental Chemistry, Umeaa University, SE-90187 Umeaa (Sweden)]. E-mail: magnus.bergknut@chem.umu.se; Sehlin, Emma [Department of Chemistry, Environmental Chemistry, Umeaa University, SE-90187 Umeaa (Sweden); Lundstedt, Staffan [Department of Chemistry, Environmental Chemistry, Umeaa University, SE-90187 Umeaa (Sweden); Andersson, Patrik L. [Department of Chemistry, Environmental Chemistry, Umeaa University, SE-90187 Umeaa (Sweden); Haglund, Peter [Department of Chemistry, Environmental Chemistry, Umeaa University, SE-90187 Umeaa (Sweden); Tysklind, Mats [Department of Chemistry, Environmental Chemistry, Umeaa University, SE-90187 Umeaa (Sweden)

    2007-01-15

    The aim of this study was to evaluate different techniques for assessing the availability of polycyclic aromatic hydrocarbons (PAHs) in soil. This was done by comparing the amounts (total and relative) taken up by the earthworm Eisenia fetida with the amounts extracted by solid-phase microextraction (SPME), semi-permeable membrane devices (SPMDs), leaching with various solvent mixtures, leaching using additives, and sequential leaching. Bioconcentration factors of PAHs in the earthworms based on equilibrium partitioning theory resulted in poor correlations to observed values. This was most notable for PAHs with high concentrations in the studied soil. Evaluation by principal component analysis (PCA) showed distinct differences between the evaluated techniques and, generally, there were larger proportions of carcinogenic PAHs (4-6 fused rings) in the earthworms. These results suggest that it may be difficult to develop a chemical method that is capable of mimicking biological uptake, and thus estimating the bioavailability of PAHs. - The total and relative amounts of PAHs extracted by abiotic techniques for assessing the bioavailability of PAHs was found to differ from the amounts taken up by Eisenia fetida.

  14. Comparison of techniques for estimating PAH bioavailability: Uptake in Eisenia fetida, passive samplers and leaching using various solvents and additives

    International Nuclear Information System (INIS)

    Bergknut, Magnus; Sehlin, Emma; Lundstedt, Staffan; Andersson, Patrik L.; Haglund, Peter; Tysklind, Mats

    2007-01-01

    The aim of this study was to evaluate different techniques for assessing the availability of polycyclic aromatic hydrocarbons (PAHs) in soil. This was done by comparing the amounts (total and relative) taken up by the earthworm Eisenia fetida with the amounts extracted by solid-phase microextraction (SPME), semi-permeable membrane devices (SPMDs), leaching with various solvent mixtures, leaching using additives, and sequential leaching. Bioconcentration factors of PAHs in the earthworms based on equilibrium partitioning theory resulted in poor correlations to observed values. This was most notable for PAHs with high concentrations in the studied soil. Evaluation by principal component analysis (PCA) showed distinct differences between the evaluated techniques and, generally, there were larger proportions of carcinogenic PAHs (4-6 fused rings) in the earthworms. These results suggest that it may be difficult to develop a chemical method that is capable of mimicking biological uptake, and thus estimating the bioavailability of PAHs. - The total and relative amounts of PAHs extracted by abiotic techniques for assessing the bioavailability of PAHs was found to differ from the amounts taken up by Eisenia fetida

  15. THE INFRARED SPECTRA OF VERY LARGE IRREGULAR POLYCYCLIC AROMATIC HYDROCARBONS (PAHs): OBSERVATIONAL PROBES OF ASTRONOMICAL PAH GEOMETRY, SIZE, AND CHARGE

    International Nuclear Information System (INIS)

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

    2009-01-01

    The mid-infrared (IR) spectra of six large, irregular polycyclic aromatic hydrocarbons (PAHs) with formulae (C 84 H 24 -C 120 H 36 ) have been computed using density functional theory (DFT). Trends in the dominant band positions and intensities are compared to those of large, compact PAHs as a function of geometry, size, and charge. Irregular edge moieties that are common in terrestrial PAHs, such as bay regions and rings with quartet hydrogens, are shown to be uncommon in astronomical PAHs. As for all PAHs comprised solely of C and H reported to date, mid-IR emission from irregular PAHs fails to produce a strong CC str band at 6.2 μm, the position characteristic of the important, class A astronomical PAH spectra. Earlier studies showed that inclusion of nitrogen within a PAH shifts this to 6.2 μm for PAH cations. Here we show that this band shifts to 6.3 μm in nitrogenated PAH anions, close to the position of the CC stretch in class B astronomical PAH spectra. Thus, nitrogenated PAHs may be important in all sources and the peak position of the CC stretch near 6.2 μm appears to directly reflect the PAH cation to anion ratio. Large irregular PAHs exhibit features at 7.8 μm but lack them near 8.6 μm. Hence, the 7.7 μm astronomical feature is produced by a mixture of small and large PAHs while the 8.6 μm band can only be produced by large compact PAHs. As with the CC str , the position and profile of these bands reflect the PAH cation to anion ratio.

  16. Fusion component design for the moving-ring field-reversed mirror reactor

    International Nuclear Information System (INIS)

    Carlson, G.A.

    1981-01-01

    This partial report on the reactor design contains sections on the following: (1) burner section magnet system design, (2) plasma ring energy recovery, (3) vacuum system, (4) cryogenic system, (5) tritium flows and inventories, and (6) reactor design and layout

  17. DNA damage in marine rock oyster (Saccostrea Cucullata) exposed to environmentally available PAHs and heavy metals along the Arabian Sea coast.

    Science.gov (United States)

    Sarker, Subhodeep; Vashistha, Deepti; Saha Sarker, Munmun; Sarkar, A

    2018-04-30

    Molecular biomarkers are used world wide for quick assessment of the immediate effect of environmental pollution on marine ecosystems. Recently, we evaluated oxidative stress responses of marine rock oyster, Saccostrea cucullata impacted due to polycyclic aromatic hydrocarbons (PAHs) accumulated in their tissues at a few sampling sites along the coast of Goa around the region of the Arabian sea coast, India (Sarkar et al., 2017). Using a combination of partial alkaline unwinding and comet assays, we now report a comprehensive study on the impairment of DNA integrity (DI) in S. cucullata due to exposure to environmentally available PAHs and also heavy metals (Pb, Cd, Cu, Fe and Mn) along the Arabian Sea coast, Goa, India exclusively around the entire coast of Goa. First, we determined significant correlation between DI in S. cucullata and the extent of exposure to and bioaccumulation of different PAH compounds including 2-3 aromatic ring PAHs (R 2 , 0.95), 4-6 aromatic ring PAHs (R 2 , 0.85), oxygenated-PAHs (oxy-PAHs, R 2 , 0.84) and total PAHs (t-PAHs, R 2 , 0.98). Second, we observed dose-dependent decrease in DI in S. cucullata with increasing concentrations of different PAH components in oyster tissues. We substantiated our field observations with appropriate laboratory controls using benzo[a]pyrene (BaP). Third, we performed stepwise multiple regression analyses of different water quality parameters including pH, salinity, temperature, dissolved oxygen (DO), biochemical oxygen demand (BOD), nitrite (NO 2 ), nitrate (NO 3 ), phosphate (PO 4 ), turbidity and also t-PAH-biota, t-PAH-water with DI as the dependent variable. Among all these parameters, only four parameters such as t-PAH-biota in combination with DO, BOD and NO 2 showed significant correlation (R¯ 2 = 0.95) with loss in DI in S. cucullata. Based on these results, we created a map indicating the percentage of DNA damage in S. cucullata exposed to PAHs and heavy metals at each sampling location along

  18. Levels of PAHs in shrimps, Penaeus monodon from Jones Creek ...

    African Journals Online (AJOL)

    High concentrations were recorded during the rainy season and during the first quarter of the year. The investigated samples were classified as minimally contaminated when compared with FDA levels of PAHs in shrimp samples. Distribution patterns showed that PAHs with 3 and 4 rings dominated confirming the pyrogenic ...

  19. One-pot three-component synthesis of quinoxaline and phenazine ring systems using Fischer carbene complexes

    Directory of Open Access Journals (Sweden)

    Priyabrata Roy

    2010-05-01

    Full Text Available One-pot three-component coupling of o-alkynylheteroaryl carbonyl derivatives with Fischer carbene complexes and dienophiles leading to the synthesis of quinoxaline and phenazine ring systems has been investigated. This involves the generation of furo[3,4-b]pyrazine and furo[3,4-b]quinoxaline as transient intermediates, which were trapped with Diels–Alder dienophiles. This is the first report on furo[3,4-b]pyrazine intermediates.

  20. The dynamical role of the central molecular ring within the framework of a seven-component Galaxy model

    Science.gov (United States)

    Simin, A. A.; Fridman, A. M.; Haud, U. A.

    1991-09-01

    A Galaxy model in which the surface density of the gas component has a sharp (two orders of magnitude) jump in the region of the outer radius of the molecular ring is constructed on the basis of observational data. This model is used to calculate the contributions of each population to the model curve of Galactic rotation. The value of the dimensionless increment of hydrodynamical instability for the gas component, being much less than 1, coincides with a similar magnitude for the same gas in the gravity field of the entire Galaxy. It is concluded that the unstable gas component of the Galaxy lies near the limit of the hydrodynamical instability, which is in accordance with the Le Chatelier principle. The stellar populations of the Galaxy probably do not affect the generation of the spiral structure in the gaseous component.

  1. Phenylacetylene and PAH

    Indian Academy of Sciences (India)

    During the last decades, polycyclic aromatic hydrocarbons (PAHs) and other related aromatic compounds, such as ionized PAHs, have received considerable attention from astronomers, astrobiologists, environmentalists, and the combustion community. In the interstellar medium, PAH like species account for up to 10% of ...

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

    Science.gov (United States)

    Choi, Sung-Deuk

    2014-02-01

    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. © 2013.

  3. A Main Ring bunch length monitor by detecting two frequency components of the beam

    International Nuclear Information System (INIS)

    Ieiri, T.; Jackson, G.

    1989-01-01

    The bunch length is measured by detecting two revolution frequency harmonics of the beam and taking the ratio of their amplitudes. Two heterodyne receivers have been made to direct them, one at 53MHz and the other at 159MHz. These signals are picked-up by a stripline detector. An analog circuit provides a signal proportional to the bunch length. The monitor measures variation of the bunch length as a function of time in the Main Ring. The measured signal, which sometimes shows that the bunches are tumbling in phase space, can be damped by feedback to the RF amplitude modulator. 9 refs., 12 figs., 1 tab

  4. Laboratory Studies of the Formation of Carbonaceous Cosmic Dust from PAH Precursors

    Science.gov (United States)

    Salama, Farid; Contreras, C. S.

    2012-05-01

    The study of the formation and destruction processes of cosmic dust is essential to understand and to quantify the budget of extraterrestrial organic molecules. Although dust with all its components plays an important role in the evolution of interstellar chemistry and in the formation of organic molecules, little is known on the formation and destruction processes of carbonaceous dust. PAHs are important chemical building blocks of interstellar dust. They are detected in interplanetary dust particles and in meteoritic samples and are an important, ubiquitous component of the interstellar medium. The formation of PAHs from smaller molecules has not been extensively studied. Therefore, it is imperative that laboratory experiments be conducted to study the dynamic processes of carbon grain formation from PAH precursors. Studies of interstellar dust analogs formed from a variety of PAH and hydrocarbon precursors as well as species that include O, N, and S, have recently been performed using the COSmIC facility in our laboratory under conditions that simulate interstellar and circumstellar environments. The species formed in the pulsed discharge nozzle (PDN) plasma source are detected and characterized with high-sensitivity cavity ringdown spectroscopy coupled to a Reflectron time-of-flight mass spectrometer (ReTOF-MS), thus providing both spectroscopic and ion mass information in-situ. We report the measurements obtained in these experiments. Studies with hydrocarbon precursors show the feasibility of specific molecules to form PAHs, while studies with carbon ring systems (benzene and derivatives, PAHs) precursors provide information on pathways toward larger carbonaceous molecules. From these unique measurements, we derive information on the size and the structure of interstellar dust grain particles, the growth and the destruction processes of interstellar dust and the resulting budget of extraterrestrial organic molecules. Acknowledgements: This research is

  5. Ordered one-component plasmas: Phase transitions, normal modes, large systems, and experiments in a storage ring

    International Nuclear Information System (INIS)

    Schiffer, J.P.

    1994-01-01

    The property of cold one-component plasmas, confined by external forces, to form an ordered array has been known for some time both from simulations and from experiment. The purpose of this talk is to summarize some recent work on simulations and some new experimental results. The author discusses some experimental work on real storage rings, magnetic storage devices in which partials circulate with large kinetic energies and for which laser cooling is used on partially ionized ions to attain temperatures ten or more orders of magnitude lower than their kinetic energies

  6. Distribution of polycyclic aromatic hydrocarbons (PAHs) in surface sediments of Pulau Tinggi, Johor

    Science.gov (United States)

    Razak, Ezzati Sulhi Abdul; Halim, Izzyan Syazwani Abdul; Ali, Masni Mohd

    2016-11-01

    Surface sediments samples were collected at 11 stations around the Pulau Tinggi, Johor in September 2015. A total of 15 PAHs were determined and quantified by gas chromatography coupled with mass spectrometry (GC-MS). The total PAH concentrations of surface sediments from Pulau Tinggi ranged from 39.61 ng/g to 149.2 ng/g and they were classified as being in low to moderate pollution range. Individual PAH analysis showed that two and three rings PAHs were the most frequently detected isomers and accounted for 22 - 46% of the total PAH concentrations. The sources of PAHs were evaluated by employing diagnostic ratiosof specific PAH compounds.PAH ratios analysis showed a prevalence of pyrogenic PAH origin at most of the stations with exception of only a few stations.

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Hui [Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China); Energy Research Institute, University of Leeds, Leeds LS2 9JT (United Kingdom); Wu, Chunfei, E-mail: c.wu@leeds.ac.uk [Energy Research Institute, University of Leeds, Leeds LS2 9JT (United Kingdom); Onwudili, Jude A. [Energy Research Institute, University of Leeds, Leeds LS2 9JT (United Kingdom); Meng, Aihong [Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China); Zhang, Yanguo, E-mail: zhangyg@tsinghua.edu.cn [Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China); Williams, Paul T., E-mail: p.t.williams@leeds.ac.uk [Energy Research Institute, University of Leeds, Leeds LS2 9JT (United Kingdom)

    2015-02-15

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

  9. Vertical profile, source apportionment, and toxicity of PAHs in sediment cores of a wharf near the coal-based steel refining industrial zone in Kaohsiung, Taiwan.

    Science.gov (United States)

    Chen, Chih-Feng; Chen, Chiu-Wen; Ju, Yun-Ru; Dong, Cheng-Di

    2016-03-01

    Three sediment cores were collected from a wharf near a coal-based steel refining industrial zone in Kaohsiung, Taiwan. Analyses for 16 polycyclic aromatic hydrocarbons (PAHs) of the US Environmental Protection Agency priority list in the core sediment samples were conducted using gas chromatography-mass spectrometry. The vertical profiles of PAHs in the core sediments were assessed, possible sources and apportionment were identified, and the toxicity risk of the core sediments was determined. The results from the sediment analyses showed that total concentrations of the 16 PAHs varied from 11774 ± 4244 to 16755 ± 4593 ng/g dry weight (dw). Generally, the vertical profiles of the PAHs in the sediment cores exhibited a decreasing trend from the top to the lower levels of the S1 core and an increasing trend of PAHs from the top to the lower levels of the S2 and S3 cores. Among the core sediment samples, the five- and six-ring PAHs were predominantly in the S1 core, ranging from 42 to 54 %, whereas the composition of the PAHs in the S2 and S3 cores were distributed equally across three groups: two- and three-ring, four-ring, and five- and six-ring PAHs. The results indicated that PAH contamination at the site of the S1 core had a different source. The molecular indices and principal component analyses with multivariate linear regression were used to determine the source contributions, with the results showing that the contributions of coal, oil-related, and vehicle sources were 38.6, 35.9, and 25.5 %, respectively. A PAH toxicity assessment using the mean effect range-median quotient (m-ERM-q, 0.59-0.79), benzo[a]pyrene toxicity equivalent (TEQ(carc), 1466-1954 ng TEQ/g dw), and dioxin toxicity equivalent (TEQ(fish), 3036-4174 pg TEQ/g dw) identified the wharf as the most affected area. The results can be used for regular monitoring, and future pollution prevention and management should target the coal-based industries in this region for pollution reduction.

  10. Five-membered rings as diazo components in optical data storage devices: An ab initio investigation of the lowest singlet excitation energies

    DEFF Research Database (Denmark)

    Åstrand, P.-O.; Sommer-Larsen, P.; Hvilsted, Søren

    2000-01-01

    been investigated as diazo components for a potential use in optical das storage materials. It is found that the diazo compounds with two heterocyclic five-membered rings have pi --> pi* excitation energies corresponding to laser wavelengths in the region 450-500 nm whereas one five-membered ring...... and a phenyl group as diazo components results in wavelengths in the region 400-335 nm. (C) 2000 Published by Elsevier Science B.V....

  11. Experience of usage of forming rings and protective caps made of PTFE on the single-component implants

    Directory of Open Access Journals (Sweden)

    S. A. Chertov

    2014-04-01

    Full Text Available Relevance. The main reason that limits the usage of single-component implants, as compared with collapsible (two-component implants is the high risk of infectious and inflammatory complications in the postoperative period and problems in prosthetics in the esthetically important areas. Therefore, the usage of elements that contribute to healing of the mucous membrane in the early stages of implantation is particularly up-to-date. Work objective is to determine the clinical effectiveness of usage of forming rings and protective caps made of PTFE on the single-component implants in the prevention of peri-implant pathology on a one-step surgical implantation. Materials and methods of the investigation. For this work we used the treatment results of 24 patients with various dentition defects. According to the single-component implant procedure 52 single-component implants were mounted. The head of monolithic implants (38 p. were isolated by rings or caps made of PTFE. For comparison, 14 implants remained bare for 2-6 weeks before the temporary prosthesis. Postoperatively, subjective feelings were noted in patients, the presence or absence of pain complaints during the examination and palpation, the nature and extent of edema, the phenomena of inflammation around the implant neck were checked. At the stage of sutures removal the degree of soft plaque deposits on the healing elements and titanium implant heads was assessed. Results of the investigation and their discussion. No effects of mucosal hyperemia around the supporting elements made of PTFE were revealed, there was no soft and hard plaque on the rings and caps in most patients of the main group. In patients of the control group, on the contrary, the appearance of the biofilm that covered the head and the implant shoulder on all abutments, which were not protected by a ring or cap, was noted. The healing period of mucous membrane in patients of the control group was longer, the quality of

  12. Preliminary estimates of dose and residual activation of selected components in ring collimation straight of the SNS

    International Nuclear Information System (INIS)

    Ludewig, H.; Catalan-Lasheras, N.; Simos, N.; Walker, J.; Mallen, A.; Wei, J.; Todosow, M.

    2000-01-01

    The highest doses to components in the SNS ring are expected to be to those located in the collimation straight section. In this paper the authors present estimated doses to magnets and cable located between collimators. In addition the buildup of relatively long half-life radioactive isotopes is estimated, following machine operation and shutdown. Finally, the potential dose to operators approaching the machine following operation and shutdown for four hours is made. The results indicate that selected components might require replacement after several years of full power operation. In addition, the reflection of gamma-rays from the tunnel walls contribute a non-negligible amount to the dose of an operator in the tunnel following machine shutdown

  13. Migration of polycyclic aromatic hydrocarbons (PAHs) in urban treatment sludge to the air during PAH removal applications.

    Science.gov (United States)

    Karaca, Gizem; Cindoruk, S Siddik; Tasdemir, Yücel

    2014-05-01

    In the present study, the amounts of polycylic aromatic hydrocarbons (PAHs) penetrating into air during PAH removal applications from the urban treatment sludge were investigated. The effects of the temperature, photocatalyst type, and dose on the PAH removal efficiencies and PAH evaporation were explained. The sludge samples were taken from an urban wastewater treatment plant located in the city of Bursa, with 585,000 equivalent population. The ultraviolet C (UV-C) light of 254 nm wavelength was used within the UV applications performed on a specially designed setup. Internal air of the setup was vacuumed through polyurethane foam (PUF) columns in order to collect the evaporated PAHs from the sludge during the PAH removal applications. All experiments were performed with three repetitions. The PAH concentrations were measured by gas chromatography-mass spectrometry (GC-MS). It was observed that the amounts of PAHs penetrating into the air were increased with increase of temperature, and more than 80% of PAHs migrated to the air consisted of 3-ring compounds during the UV and UV-diethylamine (DEA) experiments at 38 and 53 degrees C. It was determined that 40% decrease was ensured in sigma12 (total of 12) PAH amounts with UV application and 13% of PAHs in sludge penetrated into the air. In the UV-TiO2 applications, a maximum 80% of sigma12 PAH removal was obtained by adding 0.5% TiO2 of dry weight of sludge. The quantity of PAH penetrating into air did not exceed 15%. UV-TiO2 applications ensured high levels of PAH removal in the sludge and also reduced the quantity of PAH penetrating into the air. Within the scope of the samples added with DEA, there was no increase in PAH removal efficiencies and the penetration of PAHs into air was not decreased. In light of these data, it was concluded that UV-TiO2 application is the most suitable PAH removal alternative that restricts the convection of PAH pollution.

  14. Comparative effects of several cyclodextrins on the extraction of PAHs from an aged contaminated soil

    International Nuclear Information System (INIS)

    Sánchez-Trujillo, M.A.; Morillo, E.; Villaverde, J.; Lacorte, S.

    2013-01-01

    The objective of the present study was to characterise the polycyclic aromatic hydrocarbons (PAHs) content of an aged contaminated soil and to propose remediation techniques using cyclodextrins (CDs). Four CDs solutions were tested as soil decontamination tool and proved more efficient in extracting PAHs than when an aqueous solution was used; especially two chemically modified CDs resulted in higher extraction percentages than natural β-CD. The highest extraction percentages were obtained for 3-ring PAHs, because of the appropriate size and shape of these compounds relative to those of the hydrophobic cavities of the CDs studied. A detailed mechanistic interpretation of the chemical modification of CDs on the extraction of the different PAHs has been performed, and connected with the role that the different hydrophobicities of the PAHs play in the extraction behaviour observed for the 16 PAHs, limiting their accessibility and the remaining risk of those PAHs not extractable by CDs. -- Highlights: ► Four cyclodextrins (CDs) solutions were tested as soil decontamination tool for PAHs. ► Extractions with CDs were higher than with electrolyte, especially with synthetic CDs. ► Extraction capacity depends on the adequate size of PAHs and CDs hydrophobic cavity. ► 2–3 ring PAHs, the more abundant in the soil, were extracted in higher percentages. ► CDs extract preferably the less hydrophobic and more potentially toxic PAHs. -- Cyclodextrin solutions are useful and interesting tools for the decontamination of soils polluted by PAHs

  15. Biomonitoring, status and source risk assessment of polycyclic aromatic hydrocarbons (PAHs) using honeybees, pine tree leaves, and propolis.

    Science.gov (United States)

    Kargar, Navid; Matin, Golnar; Matin, Amir Abbas; Buyukisik, Hasan Baha

    2017-11-01

    In this study, to identify and quantify the sources of airborne polycyclic aromatic hydrocarbons (PAHs), we gathered honeybee, pine tree leaf, and propolis samples to serve as bioindicators from five stations in the village of "Bozkoy" in the Aliaga industrial district of Izmir (Turkey) during April-May 2014. The PAH concentrations which measured by gas chromatography (GC) varied from 261.18 to 553.33 μg kg -1 dry weight (dw) in honeybee samples, 138.57-853.67 μg kg -1 dw in pine leaf samples, and 798.61-2905.53 μg kg -1 dw in propolis samples. The total PAH concentrations can be ranked as follows: propolis > pine leaves > honeybees. The ring sequence pattern was 5 > 3 > 6 > 4 > 2 for honeybees, 5 > 3 > 4 > 6 > 2 for pine leaves, and 5 > 4 > 6 > 3 > 2 for propolis. The diagnostic ratios [fluoranthene/fluoranthene + pyrene], [indeno(1,2,3-c,d)pyrene/indeno(1,2,3-c,d)pyrene + benzo(g,h,i)perylene], and [benzo(a)anthracene/benzo(a)anthracene + chrysene] indicate coal and biomass combustion to be the dominant PAH source in the study area. In biomonitoring studies of airborne PAHs based on honeybees, fluoranthene is considered to be a characteristic PAH compound. Distribution maps with different numbers of PAH rings among the sampling sites show the advantages of honeybee samples as indicators due to the honeybee's provision of a broader range of information with respect to heavier pollutants that are typically not in the gas or suspended phase for long periods of time. Our correlation, factor analysis, and principal components analysis (PCA) results indicate potential sources of PAH pollution in pine leaves and honeybees from airborne emissions, but we found propolis to be contaminated by PAHs due to the replacement of herbal sources of resins with synthetic gummy substances from paving materials (e.g., asphalt and tar leaks). Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. A novel approach for characterization of polycyclic aromatic hydrocarbon (PAH) pollution patterns in sediments from Guanabara Bay, Rio de Janeiro, Brazil

    International Nuclear Information System (INIS)

    Christensen, Jan H.; Tomasi, Giorgio; Scofield, Arthur de Lemos; Meniconi, Maria de Fatima Guadalupe

    2010-01-01

    A novel multivariate method based on principal component analysis of pre-processed sections of chromatograms is used to characterize the complex PAH pollution patterns in sediments from Guanabara Bay, Brazil. Five distinct sources of 3- to 6-ring PAHs could be revealed. The harbour is the most contaminated site in the bay, its plume stretches in a South West to North East direction and the chemical profile indicates mainly pyrogenic sources mixed with a fraction of high-molecular-weight petrogenic PAHs. Rio Sao Joao de Meriti is the second largest source of PAHs, and introduces mainly a fraction of low-molecular-weight petrogenic PAHs from the western region of Rio de Janeiro. The sites close to the ruptured pipeline at the Duque de Caxias Refinery show a distinctive pollution pattern indicating a heavy petroleum fraction. The method also led to the identification of new potential indicator ratios also involving coeluting peaks (e.g., triphenylene and chrysene). - A novel multivariate method is used to characterize the complex PAH pollution patterns in sediments from Guanabara Bay, Brazil.

  17. Heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs) in soils of different land uses in Erbil metropolis, Kurdistan Region, Iraq.

    Science.gov (United States)

    Amjadian, Keyvan; Sacchi, Elisa; Rastegari Mehr, Meisam

    2016-11-01

    Urban soil contamination is a growing concern for the potential health impact on the increasing number of people living in these areas. In this study, the concentration, the distribution, the contamination levels, and the role of land use were investigated in Erbil metropolis, the capital of Iraqi Kurdistan. A total of 74 soil samples were collected, treated, and analyzed for their physicochemical properties, and for 7 heavy metals (As, Cd, Cr, Cu, Fe, Pb, and Zn) and 16 PAH contents. High concentrations, especially of Cd, Cu Pb, and Zn, were found. The Geoaccumulation index (I geo ), along with correlation coefficients and principal component analysis (PCA) showed that Cd, Cu, Pb, and Zn have similar behaviors and spatial distribution patterns. Heavy traffic density mainly contributed to the high concentrations of these metals. The total concentration of ∑PAHs ranged from 24.26 to 6129.14 ng/g with a mean of 2296.1 ng/g. The PAH pattern was dominated by 4- and 5-ring PAHs, while diagnostic ratios and PCA indicated that the main sources of PAHs were pyrogenic. The toxic equivalent (TEQ) values ranged from 3.26 to 362.84 ng/g, with higher values in central parts of the city. A statistically significant difference in As, Cd, Cu, Pb, Zn, and ∑PAH concentrations between different land uses was observed. The highest As concentrations were found in agricultural areas while roadside, commercial, and industrial areas had the highest Cd, Cu, Pb, Zn, and ∑PAH contents.

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

    DEFF Research Database (Denmark)

    Grung, Merete; Petersen, Karina; Fjeld, Eirik

    2016-01-01

    of the sedimentation ponds were high (1900-4200ngg(-1)), and even higher levels were observed in plants. Principal component analysis of selected ion chromatograms of PAHs showed a clear separation of plants vs. sediments. The plants preferentially accumulated the high molecular PAHs, both from sedimentation ponds......) the transfer of PAHs from road runoff material to aquatic organisms was substantial. Minnow from a sedimentation pond (Skullerud) near Oslo (Norway) had higher levels of CYP1A enzyme and DNA stand breaks than minnow from the nearby river, but high concentrations of PAH-metabolites in bile revealed that both...... populations were highly exposed. Principal component analysis revealed that CYP1A and age of fish were correlated, while levels of PAH-metabolites were not correlated to CYP1A or DNA damage. Minnow from a lake un-affected by traffic had much lower levels of PAH-metabolites than the exposed fish, and also...

  19. Relationship between polycyclic aromatic hydrocarbons (PAHs) and particle size in dated core sediments in Lake Lianhuan, Northeast China

    International Nuclear Information System (INIS)

    Sun, Li; Zang, Shuying

    2013-01-01

    Atmospheric particle associated with pyrogenic polycyclic aromatic hydrocarbons (PAHs) poses serious threats to human health by inhalation exposure, especially in semiarid areas. Hence, the distributions of PAHs and particle size in two core sediments collected from Lake Lianhuan, Northeast China were studied. The sediments were dated radiometrically, and particle size distribution and PAH concentration were evaluated and potential human health risk was assessed. From 1980 to 2007, the dominant PAHs in the two cores were 2- and 3-ring PAHs, and the concentrations of 3–6 ring PAHs gradually increased from the early 1990s. Diagnostic ratios indicated that pyrogenic PAHs were the main sources of PAHs which changed over time from combustions of wood and coal to liquid fossil fuel sources. Fine particles ( 125 μm were found. Future research should focus on the seven carcinogenic pyrogenic PAHs due to a rapidly increasing trend since 1995 based on the assessment of toxic equivalency factors. - Highlights: • PAHs and particle size in core sediments were used to evaluate the role of eolian particles in delivering pyrogenic PAHs. • Changes of PAH sources closely followed local historical socioeconomic development since 1980s. • Changes of particulate sources from eolian to lacustrine reflected the evolving history of the lake. • Significant correlations between pyrogenic PAHs and eolian particles indicated potential risk from inhalation exposure. • Petroleum source PAHs are likely to stick to coarse particles and accumulate in lake sediments by surface runoff

  20. Tests of an environmental and personnel safe cleaning process for BNL accelerator and storage ring components

    International Nuclear Information System (INIS)

    Foerster, C.L.; Lanni, C.; Lee, R.; Mitchell, G.; Quade, W.

    1996-10-01

    A large measure of the successful operation of the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory (BNL) for over a decade can be attributed to the cleaning of its UHV components during and after construction. A new UHV cleaning process, which had to be environmentally and personnel safe, was needed to replace the harsh, unfriendly process which was still in use. Dow Advanced Cleaning Systems was contracted to develop a replacement process without the use of harsh chemicals and which must clean vacuum surfaces as well as the existing process. Acceptance of the replacement process was primarily based on Photon Stimulated Desorption (PSD) measurements of beam tube samples run on NSLS beam line U10B. One meter long beam tube samples were fabricated from aluminum, 304 stainless steel and oxygen free copper. Initially, coupon samples were cleaned and passed preliminary testing for the proposed process. Next, beam tube samples of each material were cleaned, and the PSD measured on beam line U10B using white light with a critical energy of 487 ev. Prior to cleaning, the samples were contaminated with a mixture of cutting oils, lubricants, vacuum oils and vacuum grease. The contaminated samples were then baked. Samples of each material were also cleaned with the existing process after the same preparation. Beam tube samples were exposed to between 10 22 and 10 23 photons per meter for a PSD measurement. Desorption yields for H 2 , CO, CO 2 , CH 4 and H 2 O are reported for both the existing cleaning and for the replacement cleaning process. Preliminary data, residual gas scans, and PSD results are given and discussed. The new process is also compared with new cleaning methods developed in other laboratories

  1. The Asymmetry is Derived from Mechanical Interlocking of Achiral Axle and Achiral Ring Components –Syntheses and Properties of Optically Pure [2]Rotaxanes–

    Directory of Open Access Journals (Sweden)

    Keiji Hirose

    2018-01-01

    Full Text Available Rotaxanes consisting of achiral axle and achiral ring components can possess supramolecular chirality due to their unique geometrical architectures. To synthesize such chiral rotaxanes, we adapted a prerotaxane method based on aminolysis of a metacyclophane type prerotaxane that had planar chirality, which is composed of an achiral stopper unit and a crown ether type ring component. The prerotaxanes were well resolved using chiral HPLC into a pair of enantiomerically pure prerotaxanes, which were transferred into corresponding chiral rotaxanes, respectively. Obtained chiral rotaxanes were revealed to have considerable enantioselectivity.

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

    Science.gov (United States)

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

    2016-03-01

    In Naples, particulate matter PM10 associated with polycyclic aromatic hydrocarbons (PAHs) in ambient air were determined in urban background (NA01) and urban traffic (NA02) sites. The principal objective of the study was to determine the concentration and distribution of PAHs in PM10 for identification of their possible sources (through diagnostic ratio - DR and principal component analysis - PCA) and an estimation of the human health risk (from exposure to airborne TEQ). Airborne PM10 samples were collected on quartz filters using a Low Volume Sampler (LVS) for 24 h with seasonal samples (autumn, winter, spring and summer) of about 15 days each between October 2012 and July 2013. The PM10 mass was gravimetrically determined. The PM10 levels, in all seasons, were significantly higher (P gas chromatography-mass spectrometer (GC-MS) analysis. The concentration of Benzo[a]Pyrene, BaP (EU and National limit value: 1 ng m-3 in PM10), varied from 0.065 ng m-3 during autumn time to 0.872 ng m-3 in spring time (NA01) and from 0.120 ng m-3 during autumn time to 1.48 ng m-3 of winter time (NA02) with four overshoots. In NA02 the trend of Σ12 PAHs was comparable to NA01 but were observed higher values than NA01. In fact, the mean concentration of Σ12 PAHs, in urban-traffic site was generally 2 times greater than in urban-background site in all the campaigns. PAHs with 5 and 6 ring, many of which are suspected carcinogens or genotoxic agents, (i.e Benzo[a]Pyrene, Indeno[1,2,3-cd]Pyrene, Benzo[b]Fluoranthene, Benzo[k]Fluoranthene and Benzo[g,h,i]Perylene), had a large contribution (∼50-55%) of total PAHs concentration in PM10 in two sites and in each of the campaigns. Diagnostic ratio analysis and PCA suggested a substantial contributions from traffic emission with minimal influence from coal combustion and natural gas emissions. In particular diesel vehicular emissions were the major source of PAHs at the studied sites. The use of Toxicity Equivalence Quantity (TEQ

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

    Science.gov (United States)

    Karaca, Gizem

    2016-02-01

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

  4. PAH dissipation in a contaminated river sediment under oxic and anoxic conditions

    International Nuclear Information System (INIS)

    Quantin, C.; Joner, E.J.; Portal, J.M.; Berthelin, J.

    2005-01-01

    A batch experiment was conducted to compare PAH degradation in a polluted river sediment under aerobic and anaerobic conditions, and to investigate whether input of fresh organic material (cellulose) could enhance such degradation. All measurements were checked against abiotic control treatments to exclude artifacts of sample preparation and non-biological processes like aging. Three- and four-ring PAHs could be degraded by the indigenous microbial community under aerobic conditions, but anaerobic metabolism based on iron and sulphate reduction was not coupled with PAH degradation of even the simplest 3-ring compounds like phenanthrene. Cellulose addition stimulated both aerobic and anaerobic respiration, but had no effect on PAH dissipation. We conclude that natural attenuation of PAHs in polluted river sediments under anaerobic conditions is exceedingly slow. Dredging and biodegradation on land under aerobic conditions would be required to safely remediate and restore polluted sites. - Natural attenuation of PAHs under anaerobic conditions is exceedingly slow

  5. Bacteria from wheat and cucurbit plant roots metabolize PAHs and aromatic root exudates: Implications for rhizodegradation.

    Science.gov (United States)

    Ely, Cairn S; Smets, Barth F

    2017-10-03

    The chemical interaction between plants and bacteria in the root zone can lead to soil decontamination. Bacteria that degrade polycyclic aromatic hydrocarbons (PAHs) have been isolated from the rhizospheres of plant species with varied biological traits; however, it is not known what phytochemicals promote contaminant degradation. One monocot and two dicotyledon plants were grown in PAH-contaminated soil from a manufactured gas plant (MGP) site. A phytotoxicity assay confirmed greater soil decontamination in rhizospheres when compared to bulk soil controls. Bacteria were isolated from plant roots (rhizobacteria) and selected for growth on anthracene and chrysene on PAH-amended plates. Rhizosphere isolates metabolized 3- and 4-ring PAHs and PAH catabolic intermediates in liquid incubations. Aromatic root exudate compounds, namely flavonoids and simple phenols, were also substrates for isolated rhizobacteria. In particular, the phenolic compounds-morin, caffeic acid, and protocatechuic acid-appear to be linked to bacterial degradation of 3- and 4-ring PAHs in the rhizosphere.

  6. Culture-dependent and -independent approaches establish the complexity of a PAH-degrading microbial consortium

    Energy Technology Data Exchange (ETDEWEB)

    Vinas, M.; Sabate, J.; Solanas, A.M. [Barcelona Univ., Barcelona (Spain). Dept. of Microbiology; Guasp, C.; Lalucat, J. [Illes Balears Univ., Palma de Mallorca (Spain). Dept. of Biology

    2005-11-15

    Microbial consortia are used in the decontamination of polluted environmental sites. A microbial consortium obtained by batch enrichment culture is a closed system with controlled conditions in which micro-organisms with a potentially high growth rate are selected and become dominant. The aim of this study was to identify the members of consortium AM, in which earlier batch enrichment work had shown high biodegradation rates of the aromatic fraction of polycyclic aromatic hydrocarbon (PAH). The AM consortium was obtained by sequential enrichment in liquid culture with a PAH mixture of 3- and 4- ringed PAHs as the sole source of carbon and energy. The consortium was examined using a triple approach method based on various cultivation strategies, denaturing gradient electrophoresis (DGGE) and the screening of 16S and 18S rRNA gene clone libraries. Eleven different sequences by culture-dependent techniques and 7 by both DGGE and clone libraries were obtained, yielding 19 different microbial components. Proteobacteria were the dominant group, representing 83 per cent of the total, while the Cytophaga-Flexibactor-Bacteroides group (CFB) was 11 per cent, and Ascomycota fungi were 6 per cent. It was determined that {beta}-Proteobacteria were predominant in the DGGE and clone library methods, whereas they were a minority in culturable strains. The highest diversity and number of noncoincident sequences was achieved by the cultivation method that showed members of the {alpha},{beta}, and {gamma}-Proteobacteria, CFB bacterial group, and Ascomycota fungi. Only 6 of the 11 strains isolated showed PAH-degrading capability. The bacterial strain (AMS7) and the fungal strain (AMF1) achieved the greatest PAH depletion. Results indicated that polyphasic assessment is necessary for a proper understanding of the composition of a microbial consortium. It was concluded that microbial consortia are more complex than previously realized. 54 refs., 3 tabs., 3 figs.

  7. The PAH Emission Characteristics of the Reflection Nebula NGC 2023

    International Nuclear Information System (INIS)

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

    2017-01-01

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

  8. The PAH Emission Characteristics of the Reflection Nebula NGC 2023

    Energy Technology Data Exchange (ETDEWEB)

    Peeters, Els [Department of Physics and Astronomy, University of Western Ontario, London, ON N6A 3K7 (Canada); Bauschlicher, Charles W. Jr. [Entry Systems and Technology Division, Mail Stop 230-3, NASA Ames Research Center, Moffett Field, CA 94035 (United States); Allamandola, Louis J. [NASA Ames Research Center, Space Science Division, Mail Stop 245-6, Moffett Field, CA 94035 (United States); Tielens, Alexander G. G. M. [Leiden Observatory, P.O. Box 9513, 2300 RA Leiden (Netherlands); Ricca, Alessandra [Carl Sagan Center, SETI Institute, 189 N. Bernardo Avenue, Suite 100, Mountain View, CA 94043 (United States); Wolfire, Mark G., E-mail: epeeters@uwo.ca [Astronomy Department, University of Maryland, College Park, MD 20742 (United States)

    2017-02-20

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

  9. Evolution of bacterial community during bioremediation of PAHs in a coal tar contaminated soil

    Energy Technology Data Exchange (ETDEWEB)

    Lors, C.; Ryngaert, A.; Perie, F.; Diels, L.; Damidot, D. [University of Lille, Lille (France)

    2010-11-15

    The monitoring of a windrow treatment applied to soil contaminated by mostly 2, 3- and 4-ring PAHs produced by coal tar distillation was performed by following the evolution of both PAH concentration and the bacterial community. Total and PAH-degrading bacterial community structures were followed by 165 rRNA PCR-DGGE in parallel with quantification by bacterial counts and 16 PAH measurements. Six months of biological treatment led to a strong decrease in 2-, 3- and 4-ring PAH concentrations (98, 97 and 82%, respectively). This result was associated with the activity of bacterial PAH-degraders belonging mainly to the Gamma proteobacteria, in particular the Enterobacteria and Pseudomonas genera which were detected over the course of the treatment. This group was considered to be a good bioindicator to determine the potential PAH biodegradation of contaminated soil. Conversely other species like the Beta proteobacteria were detected after 3 months when 2-, 3- and 4-ring PAHs were almost completely degraded. Thus presence of the Beta proteobacteria group could be considered a good candidate indicator to estimate the endpoint of biotreatment of this type of PAH contaminated soil.

  10. Conceptual Design Report. Antiproton - Proton Collider Upgrade 20 GeV Rings. Technical Components and Civil Construction May, 1988

    Energy Technology Data Exchange (ETDEWEB)

    None

    1988-05-01

    This report contains a description of the design and cost estimate of two new 20 GeV rings which will be required to support the upgrade of the Fermilab Collider with a luminosity goal of 5x10 31 cm-2s-1. The new rings include an antiproton post-accumulator, denoted the Antiproton Super Booster (ASB), and a proton post-booster, denoted the Proton Super Booster (PSB). The siting of the rings is shown in Figure I-1. Both rings are capable of operation at 20 GeV, eliminating the need for ever again injecting beam into the Main Ring below transition, and significantly enhancing Main Ring performance. The Antiproton Super Booster is designed to accept and accumulate up to 4x1012 antiprotons from the existing Antiproton Accumulator, and deliver them to the Main Ring at 20 GeV for acceleration and injection into the Collider. It is also designed to accept diluted antiprotons from the Main Ring at 20 GeV for recooling. The PSB accepts 8.9 GeV protons from the existing Booster and accelerates them to 20 GeV for injection into the Main Ring. The PSB is designed to operate at 5 Hz. The siting shown in Figure I-1 has the attractive feature that it removes all Main Ring injection hardware from the AO straight section, opening the possibility of installing a third proton-antiproton interaction region in the Tevatron Collider.

  11. Enhanced bioremediation of PAH-contaminated soil by immobilized bacteria with plant residue and biochar as carriers

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Baoliang; Yuan, Miaoxin; Qian, Linbo [Zhejiang Univ., Hangzhou (China). Dept. of Environmental Science; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou (China)

    2012-10-15

    Polycyclic aromatic hydrocarbons (PAHs) are largely accumulated in soils in China. The immobilized-microorganism technique (IMT) is a potential approach for abating soil contamination with PAHs. However, few studies about the application of IMT to contaminated soil remediation were reported. Due to recalcitrance to decomposition, biochar application to soil may enhance soil carbon sequestration, but few studies on the application of biochars to remediation of contaminated soil were reported. In this study, we illustrated enhanced bioremediation of soil having a long history of PAH contamination by IMT using plant residues and biochars as carriers. Two PAH-degrading bacteria, Pseudomonas putida and an unidentified indigenous bacterium, were selected for IMT. The extractability and biodegradation of 15 PAHs in solution and an actual PAH-contaminated soil amended with immobilized-bacteria materials were investigated under different incubation periods. The effects of carriers and the molecular weight of PAHs on bioremediation efficiency were determined to illustrate their different bio-dissipation mechanisms of PAHs in soil. The IMT can considerably enhance the removal of PAHs. Carriers impose different effects on PAH bio-dissipation by amended soil with immobilized-bacteria, which can directly degrade the carrier-associated PAHs. The removal of PAHs from soil depended on PAH molecular weight and carrier types. Enhanced bio-dissipation by IMT was much stronger for 4- and 5-ring PAHs than for 3- and 6-ring ones in soil. Only P400 biochar-immobilized bacteria enhanced bio-dissipation of all PAHs in contaminated soil after a 90-day incubation. Biochar can promote bioremediation of contaminated soil as microbial carriers of IMT. It is vital to select an appropriate biochar as an immobilized carrier to stimulate biodegradation. It is feasible to use adsorption carriers with high sorptive capabilities to concentrate PAHs as well as microorganisms and thereby enhance

  12. THE TURBULENCE SPECTRUM OF MOLECULAR CLOUDS IN THE GALACTIC RING SURVEY: A DENSITY-DEPENDENT PRINCIPAL COMPONENT ANALYSIS CALIBRATION

    International Nuclear Information System (INIS)

    Roman-Duval, Julia; Jackson, James; Federrath, Christoph; Klessen, Ralf S.; Brunt, Christopher; Heyer, Mark

    2011-01-01

    Turbulence plays a major role in the formation and evolution of molecular clouds. Observationally, turbulent velocities are convolved with the density of an observed region. To correct for this convolution, we investigate the relation between the turbulence spectrum of model clouds, and the statistics of their synthetic observations obtained from principal component analysis (PCA). We apply PCA to spectral maps generated from simulated density and velocity fields, obtained from hydrodynamic simulations of supersonic turbulence, and from fractional Brownian motion (fBm) fields with varying velocity, density spectra, and density dispersion. We examine the dependence of the slope of the PCA pseudo-structure function, α PCA , on intermittency, on the turbulence velocity (β v ) and density (β n ) spectral indexes, and on density dispersion. We find that PCA is insensitive to β n and to the log-density dispersion σ s , provided σ s ≤ 2. For σ s > 2, α PCA increases with σ s due to the intermittent sampling of the velocity field by the density field. The PCA calibration also depends on intermittency. We derive a PCA calibration based on fBm structures with σ s ≤ 2 and apply it to 367 13 CO spectral maps of molecular clouds in the Galactic Ring Survey. The average slope of the PCA structure function, (α PCA ) = 0.62 ± 0.2, is consistent with the hydrodynamic simulations and leads to a turbulence velocity exponent of (β v ) = 2.06 ± 0.6 for a non-intermittent, low density dispersion flow. Accounting for intermittency and density dispersion, the coincidence between the PCA slope of the GRS clouds and the hydrodynamic simulations suggests β v ≅ 1.9, consistent with both Burgers and compressible intermittent turbulence.

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

    International Nuclear Information System (INIS)

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

    2016-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Boersma, C.; Bregman, J.; Allamandola, L. J., E-mail: Christiaan.Boersma@nasa.gov [NASA Ames Research Center, MS 245-6, Moffett Field, CA 94035-0001 (United States)

    2016-11-20

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

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

    Science.gov (United States)

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

    2015-03-01

    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 Σ 3,4-ring PAHs and B[a] P Equivalent 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. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Relationship between polycyclic aromatic hydrocarbons (PAHs) and particle size in dated core sediments in Lake Lianhuan, Northeast China

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Li; Zang, Shuying, E-mail: zsy6311@163.com

    2013-09-01

    Atmospheric particle associated with pyrogenic polycyclic aromatic hydrocarbons (PAHs) poses serious threats to human health by inhalation exposure, especially in semiarid areas. Hence, the distributions of PAHs and particle size in two core sediments collected from Lake Lianhuan, Northeast China were studied. The sediments were dated radiometrically, and particle size distribution and PAH concentration were evaluated and potential human health risk was assessed. From 1980 to 2007, the dominant PAHs in the two cores were 2- and 3-ring PAHs, and the concentrations of 3–6 ring PAHs gradually increased from the early 1990s. Diagnostic ratios indicated that pyrogenic PAHs were the main sources of PAHs which changed over time from combustions of wood and coal to liquid fossil fuel sources. Fine particles (< 65 μm) were the predominant particle size (56–97%). Lacustrine source (with the peak towards 200–400 μm) and eolian sources derived from short (2.0–10 and 30–65 μm) and long (0.4–1.0 μm) distance suspension were indentified from frequency distribution pattern of particle size. Significant correlations between 3–6 ring PAHs (especially carcinogenic 5–6 ring PAHs) and 10–35 μm particulate fractions indicated that eolian particles played an important role in adsorbing pyrogenic PAHs. Petroleum source of PAHs was only identified during the 1980s in one core sediments, in which positive correlations between 2-ring PAHs and particulate fractions of > 125 μm were found. Future research should focus on the seven carcinogenic pyrogenic PAHs due to a rapidly increasing trend since 1995 based on the assessment of toxic equivalency factors. - Highlights: • PAHs and particle size in core sediments were used to evaluate the role of eolian particles in delivering pyrogenic PAHs. • Changes of PAH sources closely followed local historical socioeconomic development since 1980s. • Changes of particulate sources from eolian to lacustrine reflected the

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

    Science.gov (United States)

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

    2016-04-01

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

  18. Pollution by polycyclic aromatic hydrocarbons (PAH's) in sediments and organisms from Salina Cruz Port, Oaxaca, Mexico

    International Nuclear Information System (INIS)

    Botello, A.V.; Villanueva, S.; Diaz, G.; Pica, Y.

    1995-01-01

    The presence and levels of polycyclic aromatic hydrocarbons (PAH's) in [sediments and biota from the Port of Salina Cruz, Oaxaca; were evaluated by means of gas capillary chromatography using columns of high resolution. The results show a seasonal variability of the PAH's concentrations in sediments being higher in the port area and lower in oceanic sediments. The increase of the PAH's levels in Crassostrea iridiscens and Penaeus stylirostris is important and related to the bioaccumulation process. The presence of PAH's conformed by 4 y 5 benzene rings in these species must be noted specially because they have carcinogenic properties and their effects on the local fisheries should be considered. (Author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ying, E-mail: echochen327@163.com [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: jinhui@tsinghua.edu.cn [State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084 (China)

    2013-05-15

    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

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

    International Nuclear Information System (INIS)

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

    2013-01-01

    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 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

  1. PAH processing in space

    NARCIS (Netherlands)

    Micelotta, Elisabetta Rita

    2009-01-01

    Polycyclic Aromatic Hydrocarbons (PAHs) are one of the most common chemical compounds on Earth. These big molecules are naturally present in crude oil and coal deposits, and are also formed by incomplete combustion of carbon-containing fuels, hence they are found in car exhaust, cigarette smoke and

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

    International Nuclear Information System (INIS)

    Haritash, A.K.; Kaushik, C.P.

    2009-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-09-30

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

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

    Science.gov (United States)

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

    2015-02-01

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

  5. Interstellar PAH in the Laboratory and in Space. What have we Learned from the New Generation of Laboratory and Observational Studies?

    Science.gov (United States)

    Salama, Farid

    2005-01-01

    Polycyclic Aromatic Hydrocarbons (PAHs) are an important and ubiquitous component of carbon-bearing materials in space. PAHs are the best-known candidates to account for the IR emission bands (UIR bands) and PAH spectral features are now being used as new probes of the ISM. PAHs are also thought to be among the carriers of the diffuse interstellar absorption bands (DIBs). In the model dealing with the interstellar spectral features, PAHs are present as a mixture of radicals, ions and neutral species. PAH ionization states reflect the ionization balance of the medium while PAH size, composition, and structure reflect the energetic and chemical history of the medium. A major challenge for laboratory astrophysics is to reproduce (in a realistic way) the physical conditions that exist in the emission and/or absorption interstellar zones. An extensive laboratory program has been developed at NASA Ames to assess the physical and chemical properties of PAHs in such environments and to describe how they influence the radiation and energy balance in space and the interstellar chemistry. In particular, laboratory experiments provide measurements of the spectral characteristics of interstellar PAH analogs from the ultraviolet and visible range to the infrared range for comparison with astronomical data. This paper will focus on the recent progress made in the laboratory to measure the direct absorption spectra of neutral and ionized PAHs in the gas phase in the near-UV and visible range in astrophysically relevant environments. These measurements provide data on PAHs and nanometer-sized particles that can now be directly compared to astronomical observations. The harsh physical conditions of the IS medium - characterized by a low temperature, an absence of collisions and strong VUV radiation fields - are simulated in the laboratory by associating a molecular beam with an ionizing discharge to generate a cold plasma expansion. PAH ions are formed from the neutral precursors in

  6. Distribution of polycyclic aromatic hydrocarbons (PAHs) in rivers and estuaries in Malaysia: a widespread input of petrogenic PAHs.

    Science.gov (United States)

    Zakaria, Mohamad Pauzi; Takada, Hideshige; Tsutsumi, Shinobu; Ohno, Kei; Yamada, Junya; Kouno, Eriko; Kumata, Hidetoshi

    2002-05-01

    This is the first publication on the distribution and sources of polycyclic aromatic hydrocarbons (PAHs) in riverine and coastal sediments in South East Asia where the rapid transfer of land-based pollutants into aquatic environments by heavy rainfall and runoff waters is of great concern. Twenty-nine Malaysian riverine and coastal sediments were analyzed for PAHs (3-7 rings) by gas chromatography mass spectrometry. Total PAHs concentrations in the sediment ranged from 4 to 924 ng/g. Alkylated homologues were abundant for all sediment samples. The ratio of the sum of methylphenanthrenes to phenanthrene (MP/P), an index of petrogenic PAHs contribution, was more than unity for 26 sediment samples and more than 3 for seven samples for urban rivers covering a broad range of locations. The MP/P ratio showed a strong correlation with the total PAHs concentrations, with an r2 value of 0.74. This ratio and all other compositional features indicated that Malaysian urban sediments are heavily impacted by petrogenic PAHs. This finding is in contrast to other studies reported in many industrialized countries where PAHs are mostly of pyrogenic origin. The MP/P ratio was also significantly correlated with higher molecular weight PAHs such as benzo[a]pyrene, suggesting unique PAHs source in Malaysia which contains both petrogenic PAHs and pyrogenic PAHs. PAHs and hopanes fingerprints indicated that used crankcase oil is one of the major contributors of the sedimentary PAHs. Two major routes of inputs to aquatic environments have been identified: (1) spillage and dumping of waste crankcase oil and (2) leakage of crankcase oils from vehicles onto road surfaces, with the subsequent washout by street runoff. N-Cyclohexyl-2-benzothiazolamine (NCBA), a molecular marker of street dust, was detected in the polluted sediments. NCBA and other biomarker profiles confirmed our hypothesis of the input from street dust contained the leaked crankcase oil. The fingerprints excluded crude oil

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

    Science.gov (United States)

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

    2002-11-15

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

  8. Rapid collection, detection, and assessment of environmental polycyclic aromatic hydrocarbons (PAHs)

    International Nuclear Information System (INIS)

    Johnson, T.; Huckins, J.; Petty, J.; Butorin, A.

    1995-01-01

    PAHs, an important class of environmental chemical contaminants found primarily in petroleum and coal products, frequently are the most numerous and ubiquitous organic pollutants recovered in sediment residues. PAHs are considered hazardous in water and soil because many are acutely toxic and have the potential for genotoxic activity. Selected EPA priority pollutants (2, 3, 4, and 5-ring PAHs) and complex PAH mixtures (crude oil, gasoline, and recycled motor oil) were collected and concentrated from water and sediment with semipermeable polymeric membrane devices (SPMDs) that contain a thin film of triolein. Analytes were extracted from the SPMDs by dialysis in hexane or directly by rinsing with acetone DMSO, concentrated in the carrier solvent DMSO, and detected with the luminescent bacterial assays Microtox reg-sign and Mutatox reg-sign. High SPMD-water concentration factors of PAHs appeared to correspond closely to the occurrence of PAHs in sediments previously reported in the literature; for example, pyrene had the highest SPMD concentration factor and was the most commonly found PAH in sediment residues. Mutatox reg-sign with rat hepatic S9 activation detected all PAHs tested. The PAH's molecular weight and number of rings appeared to directly influence acute toxicity (EC50, microg/mL); for example, two-ring naphthalene had an EC50 value of 0.78 whereas five-ring benzo(a)pyrene had an EC50 value of 15.0, about a twenty-fold difference, Microtox reg-sign and Mutatox reg-sign, in combination with SPMDs were able to rapidly (< 24h) assess the bioavailability, toxicity, and genotoxicity of these environmental PAHs

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

    Science.gov (United States)

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

    2016-10-01

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

  10. Source apportionment of polycyclic aromatic hydrocarbons (PAHs) in sediments from Khuzestan province, Iran

    DEFF Research Database (Denmark)

    Lübeck, Josephine; Poulsen, Kristoffer Gulmark; Knudsen, Sofie B.

    2016-01-01

    of polycyclic aromatic hydrocarbon (PAH) pollution. A four-component principal component analysis (PCA) model was obtained. While principal component 1 (PC1) was related to the total concentration of PAHs, the remaining PCs described three distinct sources: PC2 and PC3 collectively differentiate between...

  11. PAHs pollution from traffic sources in air of Hangzhou, China: trend and influencing factors.

    Science.gov (United States)

    Zhu, Li-Zhong; Wang, Jing

    2005-01-01

    PAHs pollution in air of arterial roads was investigated from October 1998 to October 2001 in Hangzhou, China. The results showed that sigma10 PAHs was 13-36 microg/m3, among which, BaP, a strong carcinogenic kind ranged from 0.034 microg/m3 to 0.12 microg/m3. PAHs pollutions in four seasons were winter > autumn > spring-summer. The annual averages of sigmaPAHs concentration were 25 microg/m3 for 1999, 28 microg/m3 for 2000, and 29 microg/m3 for 2001, respectively. Leaded gasoline was banned in December 1998 in Hangzhou, thus comparative measurements with PAHs in leaded and lead-free gasoline powered motor exhausts made it certain that the use of lead-free gasoline leaded to a heavier PAHs pollution in roadside air from December, 1998, in China, and sigmaPAHs in air samples after the lead-banning were more than twice of that in samples before the action. For the large contribution of vehicle discharge to air pollution in roadside, further research was performed to suggest the factors influencing PAHs distribution in vehicle exhaust in order to control air pollution effectively. Compared to gasoline engines, emissions from diesel engines were less toxic, although they might produce more PAHs. Of the same vehicular and oil type, automobiles of longer mileages produced more toxic PAHs. PAHs distributions in the vehicular exhausts were related to the oil type. Large difference was found in the abundance of 3-, 5- and 6-ring PAHs between exhausts from gasoline and diesel oil engines. Diesel oil engines produced relative lighter PAHs such as NAPH, ACEN, FLUOR, while gasoline engines emitted heavier kinds such as BkF, IN and BP. The automobile produced more PAHs with the increase of mileage especially FLUR, PY, BaP, BP. Some significant ratios for traffic source in Hangzhou such as PHEN/AN, FLUR/PY, IN/BP were 0.50-4.3, 0.58-7.4, 0.51-1.5, respectively. A source fingerprint for vehicle exhausts of a mixture of vehicle and oil types in the city district for light

  12. The North Cape oil spill assessment: PAHs in oil

    International Nuclear Information System (INIS)

    Brown, J.; Boehm, P. D.; Hardestine, J. H.; Douglas, G. S.

    1997-01-01

    The North Cape oil spill in January 1996 resulted in the release of an estimated 827,000 gallons of No. 2 home heating oil into the nearshore turbulent waters of coastal Rhode Island. The oil was mixed into the water column and was transported on the surface as well as below the surface. Some of the spilled oil entered the coastal ponds behind the beaches. Sampling and chemical analysis for detailed suites of petroleum saturated and polycyclic aromatic hydrocarbons (PAHs) was undertaken as part of the assessment of the fate of the oil spill and of the exposure to the marine environment. The ponds were found to contain significant quantities of background petroleum hydrocarbons, including petrogenic PAHs and combustion PAHs. Initial assessment pointed (incorrectly as it turned out) to widespread contamination due only to the North Cape spill. Application of advanced chemical fingerprinting approaches, and geochemical biomarker data illustrated that many of the PAHs consisted of combustion-related 4- and 5-ringed PAHs, attributable to diesel fuel used routinely by boats in the area. The analysis demonstrated that the use of non-specific total PAH data and insufficient fingerprinting and allocation of petrogenic residues has the potential to overestimate contamination and hence injury to the environment in similar oil spill situations

  13. Microbial degradation of polycyclic aromatic hydrocarbons (PAHs). Pt. 1

    International Nuclear Information System (INIS)

    Eichler, B.; Bryniok, D.; Vorbeck, C.; Lutz, M.; Ackermann, B.; Freier-Schroeder, D.; Knackmuss, H.J.

    1992-01-01

    Productive degradation of the higher molecular PAHs benz(a)anthracene (four rings), benzo(a)pyrene and benzo(k)fluoranthene (five rings) through pure bacterial cultures is demonstrated in this paper for the first time. Consequently, a degradation potential for lower and higher molecular polycyclic aromatics up to five rings exists both in the ground of the fromer coking site and in the ground of the former gas works of Stuttgart. Further samples from contaminated soils, coking waste water and sediments showed similar results. This suggests that the bacterial flora present in the soil itself can be successfully used to clean up contaminated ground. (orig.) [de

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

    International Nuclear Information System (INIS)

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

    2015-01-01

    Infrared spectroscopic studies of ultraviolet (UV) irradiated, water-rich, cosmic ice analogs containing small polycyclic aromatic hydrocarbons (PAHs) are described. The irradiation studies of anthracene:H 2 O, pyrene:H 2 O, and benzo[ghi]perylene:H 2 O ices (14 K) at various concentrations reported by Bouwman et al. are extended. While aromatic alcohols and ketones have been reported in residues after irradiated PAH:H 2 O ices were warmed to 270 K, it was not known if they formed during ice irradiation or during warm-up when reactants interact as H 2 O 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:H 2 O ices considered here. Little evidence is found for hydrogenation at 14 K, consistent with the findings of Gudipati and Yang. Addition of O and OH to the parent PAH is the dominant photochemical reaction, but PAH erosion to smaller PAHs (producing CO 2 and H 2 CO) is also important. DFT spectra are used to assess the contribution of PAH-related species to interstellar absorption features from 5 to 9 μm. The case is made that PAH cations are important contributors to the C2 component and PAH(OH) 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 H 2 O. PAHs, their photoproducts, and ion-mediated processes should therefore be considered when modeling interstellar ice processes

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

    Energy Technology Data Exchange (ETDEWEB)

    Cook, Amanda M.; Mattioda, Andrew L.; Roser, Joseph; Bregman, Jonathan [NASA Ames Research Center, PO Box 1, M/S 245-6, Moffett Field, CA 94035 (United States); Ricca, Alessandra; Allamandola, Louis J. [SETI Institute, 189 North Bernardo Avenue, Mountain View, CA 94043 (United States); Bouwman, Jordy [Radboud University Nijmegen, Institute for Molecules and Materials, Toernooiveld 5, 6525 ED Nijmegen (Netherlands); Linnartz, Harold [Sackler Laboratory for Astrophysics, Leiden Observatory, University of Leiden, PO Box 9513, NL2300 RA Leiden (Netherlands)

    2015-01-20

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

  16. PAH fluxes in the Laja Lake of south central Chile Andes over the last 50 years: Evidence from a dated sediment core

    International Nuclear Information System (INIS)

    Quiroz, Roberto; Popp, Peter; Urrutia, Roberto; Bauer, Coretta; Araneda, Alberto; Treutler, Hanns-Christian; Barra, Ricardo

    2005-01-01

    This paper reports the occurrence of polyaromatic hydrocarbons (PAHs) deposition inferred from a sediment core of an Andean lake in south central Chile. Sediments were carefully collected from one of the deepest section of the lake and sliced every 1 cm. The samples were analyzed for PAHs, 137 Cs, 210 Pb, organic carbon and grain-size. The stratigraphic chronology and the sedimentation rates were estimated using the sedimentary signature left by the 137 Cs and 210 Pb fallout as temporal markers. PAHs were quantified by HPLC-fluorescence detection (HPLC-Fluorescence). 15 priority EPA PAHs were analyzed in this study. Based on these results, PAH deposition over the last 50 years was estimated (a period characterized by an important intervention in the area). PAH concentration ranged from 226 to 620 ng g -1 d.w. The highest concentrations of PAHs were found in the core's bottom. The PAH profile is dominated by the presence of perylene indicating a natural source of PAH. In addition, two clear PAH deposition periods could be determined: the most recent with two-four rings PAHs, the older one with five-seven rings predomination. Determined fluxes where 71 to 972 μg m -2 year -1 , dominated by perylene deposition. PAH levels and fluxes are lower compared to the levels found in sediments from remote lakes in Europe and North America. It is concluded that the main source of PAHs into the Laja Lake sediments are of natural origin

  17. Phototransformation rate constants of PAHs associated with soot particles

    International Nuclear Information System (INIS)

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

    2013-01-01

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

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

    Science.gov (United States)

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

    2018-03-01

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

  19. Biodegradation of Mixed PAHs by PAH-Degrading Endophytic Bacteria

    Directory of Open Access Journals (Sweden)

    Xuezhu Zhu

    2016-08-01

    Full Text Available Endophytic bacteria can promote plant growth, induce plant defence mechanisms, and increase plant resistance to organic contaminants. The aims of the present study were to isolate highly PAH-degrading endophytic bacteria from plants growing at PAH-contaminated sites and to evaluate the capabilities of these bacteria to degrade polycyclic aromatic hydrocarbons (PAHs in vitro, which will be beneficial for re-colonizing target plants and reducing plant PAH residues through the inoculation of plants with endophytic bacteria. Two endophytic bacterial strains P1 (Stenotrophomonas sp. and P3 (Pseudomonas sp., which degraded more than 90% of phenanthrene (PHE within 7 days, were isolated from Conyza canadensis and Trifolium pretense L., respectively. Both strains could use naphthalene (NAP, PHE, fluorene (FLR, pyrene (PYR, and benzo(apyrene (B(aP as the sole sources of carbon and energy. Moreover, these bacteria reduced the contamination of mixed PAHs at high levels after inoculation for 7 days; strain P1 degraded 98.0% NAP, 83.1% FLR, 87.8% PHE, 14.4% PYR, and 1.6% B(aP, and strain P3 degraded 95.3% NAP, 87.9% FLR, 90.4% PHE, 6.9% PYR, and negligible B(aP. Notably, the biodegradation of PAHs could be promoted through additional carbon and nitrogen nutrients; therein, beef extract was suggested as the optimal co-substrate for the degradation of PAHs by these two strains (99.1% PHE was degraded within 7 days. Compared with strain P1, strain P3 has more potential for the use in the removal of PAHs from plant tissues. These results provide a novel perspective in the reduction of plant PAH residues in PAH-contaminated sites through inoculating plants with highly PAH-degrading endophytic bacteria.

  20. Polycyclic aromatic hydrocarbons (PAHs) biodegradation potential and diversity of microbial consortia enriched from tsunami sediments in Miyagi, Japan

    Energy Technology Data Exchange (ETDEWEB)

    Bacosa, Hernando Pactao, E-mail: hernando.bacosa@utexas.edu [Graduate School of Environmental Studies, Tohoku University, Aoba 6-6-20, Aramaki, Aoba-ku, Sendai 980-8579 (Japan); Marine Science Institute, The University of Texas at Austin, 750 Channel View Drive, Port Aransas, TX 78373 (United States); Inoue, Chihiro [Graduate School of Environmental Studies, Tohoku University, Aoba 6-6-20, Aramaki, Aoba-ku, Sendai 980-8579 (Japan)

    2015-02-11

    Highlights: • Most bacterial consortia from tsunami sediment degraded PAH mixture and pyrene. • The consortia were dominated by known and unknown PAHs-degrading bacteria. • Dokdonella clone is a potential new species and PAH degrader from tsunami sediment. • PAH-RHDα is better than nidA gene for estimating pyrene-degraders in the consortia. • First report on the PAH degradation and PAH-degrading bacteria from tsunami sediment. - Abstract: The Great East Japan Earthquake caused tsunamis and resulted in widespread damage to human life and infrastructure. The disaster also resulted in contamination of the environment by chemicals such as polycyclic aromatic hydrocarbons (PAHs). This study was conducted to investigate the degradation potential and describe the PAH-degrading microbial communities from tsunami sediments in Miyagi, Japan. PAH-degrading bacteria were cultured by enrichment using PAH mixture or pyrene alone as carbon and energy sources. Among the ten consortia tested for PAH mixture, seven completely degraded fluorene and more than 95% of phenanthrene in 10 days, while only four consortia partially degraded pyrene. Six consortia partially degraded pyrene as a single substrate. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) revealed that each sample was dominated by unique microbial populations, regardless of sampling location. The consortia were dominated by known PAHs degraders including Sphingomonas, Pseudomonas, and Sphingobium; and previously unknown degraders such as Dokdonella and Luteimonas. A potentially novel and PAH-degrading Dokdonella was detected for the first time. PAH-ring hydroxylating dioxygenase (PAH-RHDα) gene was shown to be more effective than nidA in estimating pyrene-degrading bacteria in the enriched consortia. The consortia obtained in this study are potential candidates for remediation of PAHs contaminated soils.

  1. Polycyclic aromatic hydrocarbons (PAHs) biodegradation potential and diversity of microbial consortia enriched from tsunami sediments in Miyagi, Japan

    International Nuclear Information System (INIS)

    Bacosa, Hernando Pactao; Inoue, Chihiro

    2015-01-01

    Highlights: • Most bacterial consortia from tsunami sediment degraded PAH mixture and pyrene. • The consortia were dominated by known and unknown PAHs-degrading bacteria. • Dokdonella clone is a potential new species and PAH degrader from tsunami sediment. • PAH-RHDα is better than nidA gene for estimating pyrene-degraders in the consortia. • First report on the PAH degradation and PAH-degrading bacteria from tsunami sediment. - Abstract: The Great East Japan Earthquake caused tsunamis and resulted in widespread damage to human life and infrastructure. The disaster also resulted in contamination of the environment by chemicals such as polycyclic aromatic hydrocarbons (PAHs). This study was conducted to investigate the degradation potential and describe the PAH-degrading microbial communities from tsunami sediments in Miyagi, Japan. PAH-degrading bacteria were cultured by enrichment using PAH mixture or pyrene alone as carbon and energy sources. Among the ten consortia tested for PAH mixture, seven completely degraded fluorene and more than 95% of phenanthrene in 10 days, while only four consortia partially degraded pyrene. Six consortia partially degraded pyrene as a single substrate. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) revealed that each sample was dominated by unique microbial populations, regardless of sampling location. The consortia were dominated by known PAHs degraders including Sphingomonas, Pseudomonas, and Sphingobium; and previously unknown degraders such as Dokdonella and Luteimonas. A potentially novel and PAH-degrading Dokdonella was detected for the first time. PAH-ring hydroxylating dioxygenase (PAH-RHDα) gene was shown to be more effective than nidA in estimating pyrene-degrading bacteria in the enriched consortia. The consortia obtained in this study are potential candidates for remediation of PAHs contaminated soils

  2. Analysis of the impact of the eastern ring road of Lodz on selected components of the environment

    Science.gov (United States)

    Janas, , Monika; Zawadzka, Alicja

    2018-01-01

    The geographical location of Poland and the pursuit of economic growth make it necessary to build a sufficiently equipped and compact network of expressways and motorways. Such investments do not, however, leave the environment unaffected. The work analyzes changes that have occurred in the natural environment under the influence of the construction and operation of Lodz eastern ring road being a section of the A1 motorway commissioned in August 2016. Changes in the pollution of air, soil and acoustic climate are discussed in detail.

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

    International Nuclear Information System (INIS)

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

    2014-01-01

    We used land-use analysis, PAH concentrations and assemblages, and multivariate statistics to identify sediment PAH sources in a small (∼1303 km 2 ) urbanizing watershed located in South-Central, Pennsylvania, USA. A geographic information system (GIS) was employed to quantify land-use features that may serve as PAH sources. Urban PAH concentrations were three times higher than rural levels, and were significantly and highly correlated with combined residential/commercial/industrial land use. Principal components analysis (PCA) was used to group sediments with similar PAH assemblages, and correlation analysis compared PAH sediment assemblages to common PAH sources. The strongest correlations were observed between rural sediments (n = 7) and coke-oven emissions sources (r = 0.69–0.78, n = 5), and between urban sediments (n = 22) and coal-tar-based sealcoat dust (r = 0.94, n = 47) suggesting that coal-tar-based sealcoat is an important urban PAH source in this watershed linked to residential and commercial/industrial land use. -- Highlights: • Total PAH concentrations were measured at 35 sites along an urbanizing land-use gradient. • PAH concentrations increased with increasing urban land-use. • Urban land-use metrics were measured at three spatial scales using GIS. • PAH assemblages indicate coal-tar-based sealcoat is a major urban PAH source. • PAH assemblages indicate coke-oven emissions are an important rural PAH source. -- Coal-tar-based sealcoated pavement is a major PAH source to urban freshwater stream sediments in south-central Pennsylvania, USA

  4. Dermal tumorigen PAH and complex mixtures for biological research

    International Nuclear Information System (INIS)

    Griest, W.H.; Guerin, M.R.; Ho, C.

    1985-01-01

    Thirteen commercially available, commonly reported four-five ring dermal tumorigen PAHs, were determined in a set of complex mixtures consisting of crude and upgraded coal liquids, and petroleum crude oils and their distillate fractions. Semi-preparative scale, normal phase high performance liquid chromatographic fractionation followed by capillary column gas chromatography or gas chromatography-mass spectroscopy were used for the measurements. Deuterated or carbon-14 labeled PAH served as internal standards or allowed recovery corrections. Approaches for the preparation and measurement of radiolabeled PAH were examined to provide chemical probes for biological study. Synthetic routes for production of 14 C labeled dihydrobenzo[a]pyrene and 14 C- or 3 H 10-azabenzo[a]pyrene are being studied to provide tracers for fundamental studies in tracheal transplant and skin penetration systems. (DT)

  5. Ring Theory

    CERN Document Server

    Jara, Pascual; Torrecillas, Blas

    1988-01-01

    The papers in this proceedings volume are selected research papers in different areas of ring theory, including graded rings, differential operator rings, K-theory of noetherian rings, torsion theory, regular rings, cohomology of algebras, local cohomology of noncommutative rings. The book will be important for mathematicians active in research in ring theory.

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

    Science.gov (United States)

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

    2011-11-01

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

  7. Radiation shield ring assembly and method of disassembling components of a nuclear steam generator using such assembly

    International Nuclear Information System (INIS)

    Meuschke, R.E.; Wolfe, D.L.

    1982-01-01

    This invention relates to an apparatus and a method for cutting, within a shielding confinement, the irradiated components of a nuclear steam generator to reduce such components to a size to permit their subsequent removal from the containment structure of the generator

  8. Mitigation of PAH and nitro-PAH emissions from nonroad diesel engines.

    Science.gov (United States)

    Liu, Z Gerald; Wall, John C; Ottinger, Nathan A; McGuffin, Dana

    2015-03-17

    More stringent emission requirements for nonroad diesel engines introduced with U.S. Tier 4 Final and Euro Stage IV and V regulations have spurred the development of exhaust aftertreatment technologies. In this study, several aftertreatment configurations consisting of diesel oxidation catalysts (DOC), diesel particulate filters (DPF), Cu zeolite-, and vanadium-based selective catalytic reduction (SCR) catalysts, and ammonia oxidation (AMOX) catalysts are evaluated using both Nonroad Transient (NRTC) and Steady (8-mode NRSC) Cycles in order to understand both component and system-level effects of diesel aftertreatment on emissions of polycyclic aromatic hydrocarbons (PAH) and their nitrated derivatives (nitro-PAH). Emissions are reported for four configurations including engine-out, DOC+CuZ-SCR+AMOX, V-SCR+AMOX, and DOC+DPF+CuZ-SCR+AMOX. Mechanisms responsible for the reduction, and, in some cases, the formation of PAH and nitro-PAH compounds are discussed in detail, and suggestions are provided to minimize the formation of nitro-PAH compounds through aftertreatment design optimizations. Potency equivalency factors (PEFs) developed by the California Environmental Protection Agency are then applied to determine the impact of aftertreatment on PAH-derived exhaust toxicity. Finally, a comprehensive set of exhaust emissions including criteria pollutants, NO2, total hydrocarbons (THC), n-alkanes, branched alkanes, saturated cycloalkanes, aromatics, aldehydes, hopanes and steranes, and metals is provided, and the overall efficacy of the aftertreatment configurations is described. This detailed summary of emissions from a current nonroad diesel engine equipped with advanced aftertreatment can be used to more accurately model the impact of anthropogenic emissions on the atmosphere.

  9. Emission characteristics for gaseous- and size-segregated particulate PAHs in coal combustion flue gas from circulating fluidized bed (CFB) boiler.

    Science.gov (United States)

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

    2018-07-01

    The partitioning behavior of polycyclic aromatic hydrocarbons (PAHs) between gaseous and particulate phases from coal-fired power plants (CFPPs) is critically important to predict PAH removal by dust control devices. In this study, 16 US-EPA priority PAHs in gaseous and size-segregated particulate phases at the inlet and outlet of the fabric filter unit (FFs) of a circulating fluidized bed (CFB) boiler were analyzed. The partitioning mechanisms of PAHs between gaseous and particulate phases and in particles of different size classes were investigated. We found that the removal efficiencies of PAHs are 45.59% and 70.67-89.06% for gaseous and particulate phases, respectively. The gaseous phase mainly contains low molecular weight (LMW) PAHs (2- and 3-ring PAHs), which is quite different from the particulate phase that mainly contains medium and high molecular weight (MMW and HMW) PAHs (4- to 6-ring PAHs). The fractions of LMW PAHs show a declining trend with the decrease of particle size. The gas-particle partitioning of PAHs is primarily controlled by organic carbon absorption, in addition, it has a clear dependence on the particle sizes. Plot of log (TPAH/PM) against logD p shows that all slope values were below -1, suggesting that PAHs were mainly adsorbed to particulates. The adsorption effect of PAHs in size-segregated PMs for HMW PAHs is more evident than LMW PAHs. The particle size distributions (PSDs) of individual PAHs show that most of PAHs exhibit bi-model structures, with one mode peaking in the accumulation size range (2.1-1.1 μm) and another mode peaking in coarse size range (5.8-4.7 μm). The intensities of these two peaks vary in function of ring number of PAHs, which is likely attributed to Kelvin effect that the less volatile HMW PAH species preferentially condense onto the finer particulates. The emission factor of PAHs was calculated as 3.53 mg/kg of coal burned, with overall mean EF PAH of 0.55 and 2.98 mg/kg for gaseous and particulate

  10. Imaging a Central Ionized Component, a Narrow Ring, and the CO Snowline in the Multigapped Disk of HD 169142

    Energy Technology Data Exchange (ETDEWEB)

    Macías, Enrique; Anglada, Guillem; Osorio, Mayra; Gómez, José F. [Instituto de Astrofísica de Andalucía (CSIC) Glorieta de la Astronomía s/n E-18008 Granada (Spain); Torrelles, José M. [Institut de Ciències de l’Espai (CSIC) and Institut de Ciències del Cosmos (UB)/IEEC, Can Magrans S/N, Cerdanyola del Vallès, Barcelona (Spain); Carrasco-González, Carlos; Rodríguez, Luis F.; Sierra, Anibal, E-mail: emacias@bu.edu [Instituto de Radioastronomía y Astrofísica UNAM, Apartado Postal 3-72 (Xangari), 58089 Morelia, Michoacán (Mexico)

    2017-04-01

    We report Very Large Array observations at 7 mm, 9 mm, and 3 cm toward the pre-transitional disk of the Herbig Ae star HD 169142. These observations have allowed us to study the millimeter emission of this disk with the highest angular resolution so far (0.″12 × 0.″09, or 14 au × 11 au, at 7 mm). Our 7 and 9 mm images show a narrow ring of emission at a radius of ∼25 au tracing the outer edge of the inner gap. This ring presents an asymmetric morphology that could be produced by dynamical interactions between the disk and forming planets. Additionally, the azimuthally averaged radial intensity profiles of the 7 and 9 mm images confirm the presence of the previously reported gap at ∼45 au and reveal a new gap at ∼85 au. We analyzed archival DCO{sup +}(3–2) and C{sup 18}O(2–1) ALMA observations, showing that the CO snowline is located very close to this third outer gap. This suggests that growth and accumulation of large dust grains close to the CO snowline could be the mechanism responsible for this proposed outer gap. Finally, a compact source of emission is detected at 7 mm, 9 mm, and 3 cm toward the center of the disk. Its flux density and spectral index indicate that it is dominated by free–free emission from ionized gas, which could be associated with the photoionization of the inner disk, an independent object, or an ionized jet.

  11. Imaging a Central Ionized Component, a Narrow Ring, and the CO Snowline in the Multigapped Disk of HD 169142

    International Nuclear Information System (INIS)

    Macías, Enrique; Anglada, Guillem; Osorio, Mayra; Gómez, José F.; Torrelles, José M.; Carrasco-González, Carlos; Rodríguez, Luis F.; Sierra, Anibal

    2017-01-01

    We report Very Large Array observations at 7 mm, 9 mm, and 3 cm toward the pre-transitional disk of the Herbig Ae star HD 169142. These observations have allowed us to study the millimeter emission of this disk with the highest angular resolution so far (0.″12 × 0.″09, or 14 au × 11 au, at 7 mm). Our 7 and 9 mm images show a narrow ring of emission at a radius of ∼25 au tracing the outer edge of the inner gap. This ring presents an asymmetric morphology that could be produced by dynamical interactions between the disk and forming planets. Additionally, the azimuthally averaged radial intensity profiles of the 7 and 9 mm images confirm the presence of the previously reported gap at ∼45 au and reveal a new gap at ∼85 au. We analyzed archival DCO + (3–2) and C 18 O(2–1) ALMA observations, showing that the CO snowline is located very close to this third outer gap. This suggests that growth and accumulation of large dust grains close to the CO snowline could be the mechanism responsible for this proposed outer gap. Finally, a compact source of emission is detected at 7 mm, 9 mm, and 3 cm toward the center of the disk. Its flux density and spectral index indicate that it is dominated by free–free emission from ionized gas, which could be associated with the photoionization of the inner disk, an independent object, or an ionized jet.

  12. Enhanced PM10 bounded PAHs from shipping emissions

    Science.gov (United States)

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

    2015-05-01

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

  13. The formation of aromatics and PAH's in laminar flames

    International Nuclear Information System (INIS)

    Marinov, N M; Pitz, W J; Westbrook, C K

    1999-01-01

    The formation of aromatics and PAH's is an important problem in combustion. These compounds are believed to contribute to the formation of soot whose emission from diesel engines is regulated widely throughout the industrial world. Additionally, the United States Environmental Protection Agency regulates the emission of many aromatics and PAH species from stationary industrial burners, under the 1990 Clean Air Act Amendments. The above emission regulations have created much interest in understanding how these species are formed in combustion systems. Much previous work has been done on aromatics and PAH's. The work is too extensive to review here, but is reviewed in Reference 1. A few recent developments are highlighted here. McEnally, Pfefferle and coworkers have studied aromatic, PAH and soot formation in a variety of non-premixed flames with hydrocarbon additives[2-4]. They found additives that contain a C5 ring increase the concentration of aromatics and soot[4]. Howard and coworkers have studied the formation of aromatic and PAH's in low pressure, premixed, laminar hydrocarbon flames. They found the cyclopentadienyl radical to be a key species in naphthalene formation in a fuel-rich, benzene/Ar/O2 flame[5

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

    Science.gov (United States)

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

    2018-06-15

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

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

    Science.gov (United States)

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

    2018-05-15

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

  16. Occurrence of polycyclic aromatic hydrocarbons (PAHs in beached plastic pellets from Mumbai coast, India

    Directory of Open Access Journals (Sweden)

    HB Jayasiri

    2014-06-01

    Full Text Available PAHs are a class of ubiquitous pollutants which consist of two or more fused benzene rings in various arrangements. A number of PAH compounds are known carcinogens and bioaccumulate and biomagnify. These compounds originate naturally as well as anthropogenically through oil spills, incineration of waste and combustion of fossil fuels and wood. The environmental consequence of Plastic pellets is the sorption organic pollutants on their surface from the sea surface microlayer (SML where the hydrophobic contaminants are known to be enriched. The plastic pellets were collected along the recent high tide line from four beaches of Mumbai coast bimonthly during May 2011 - March 2012. A total of 72 pools of plastic pellets were extracted, fractionated and analysed by Gas Chromatograph coupled to a mass spectrometer to evaluate the extent and sources of 16 PAHs. The mean ΣPAH concentration in pellets was 9202.30±114.89 ng g-1 with a wide range (35.4-46191.58 ng g-1. The concentration of fluorene was found to be the highest (1606.30±251.54 ng g-1 followed by anthracene, chrysene and phenanthrene. The ΣPAH concentration was significantly varied among months and there was no significant difference among sites at  p=0.05. The 2-3 aromatic ring compounds accounted for 60% of the total PAHs in pellets of Mumbai coast while 4 rings and 5-6 rings compounds accounted for 26 and 14%, respectively. The ratio of low and high molecular weight PAHs indicated that the contamination by petrogenic sources was predominant over the pyrogenic ones in plastic pellets suggesting oil pollution in coastal area of Mumbai.Keywords: plastic pellets, PAHs, Mumbai, sources

  17. Occurrence of polycyclic aromatic hydrocarbons (PAHs) in beached plastic pellets from Mumbai coast, India

    OpenAIRE

    HB Jayasiri; CS Purushothaman; V Vennila

    2014-01-01

    PAHs are a class of ubiquitous pollutants which consist of two or more fused benzene rings in various arrangements. A number of PAH compounds are known carcinogens and bioaccumulate and biomagnify. These compounds originate naturally as well as anthropogenically through oil spills, incineration of waste and combustion of fossil fuels and wood. The environmental consequence of Plastic pellets is the sorption organic pollutants on their surface from the sea surface microlayer (SML) where the hy...

  18. Bimonthly assessment of PAH content in wild mussels from the Spanish Atlantic Coast

    Directory of Open Access Journals (Sweden)

    Juan Antonio Campillo

    2014-06-01

    Full Text Available During 2013-14 wild mussels were bimonthly sampled in five stations along the Spanish Atlantic coast in order to assess any temporal variation in the concentration of parent PAHs. The sampling stations selected (Oia, Raxó, Mera, Avilés and Pedreña included both polluted and unpolluted sites and tried to reflect the different situations in the area (coastal and more estuarine waters. The samples were shipped to the lab and three homogenates from each site were prepared and frozen until analysis. 13 parent PAHs were quantified using HPLC with fluorescence detection. In general, the highest concentrations were found in the January-March sampling, during the pre-spawning period. PAHs contents were related to mussel biochemical composition, mainly carbohydrates and lipids, and to mussel reproductive stage. In general the 4-ring PAHs is the most abundant group of PAHs. The input of the HMW PAHs (4-5 rings to the total PAH burden generally increases in the winter months probably due to both different sources in that season (building heatings and the remobilization of sediments.

  19. UV action spectroscopy of protonated PAH derivatives. Methyl substituted quinolines

    DEFF Research Database (Denmark)

    Klærke, Benedikte; Holm, Anne; Andersen, Lars Henrik

    2011-01-01

    using the electrostatic storage ring ELISA, an electrospray ion source and 3 ns UV laser pulses. Results. It is shown that the absorption profile is both redshifted and broadened when moving the methyl group from the heterocycle containing nitrogen to the homoatomic ring. The absorption profiles......Aims. We investigate the production of molecular photofragments upon UV excitation of PAH derivatives, relevant for the interstellar medium. Methods. The action absorption spectra of protonated gas-phase methyl-substituted quinolines (CH3−C9H7NH+) have been recorded in the 215–338 nm spectral range...

  20. In situ phytoremediation of PAH-contaminated soil by intercropping alfalfa (Medicago sativa L.) with tall fescue (Festuca arundinacea Schreb.) and associated soil microbial activity

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Mingming; Fu, Dengqiang; Teng, Ying; Shen, Yuanyuan; Luo, Yongming; Li, Zhengao [Chinese Academy of Sciences, Nanjing (China). Key Laboratory of Soil Environment and Pollution Remediation; Christie, Peter [Agri-Food and Biosciences Institute, Belfast (United Kingdom). Agri-Environment Branch

    2011-09-15

    Purpose: A 7-month field experiment was conducted to investigate the polycyclic aromatic hydrocarbon (PAH) remediation potential of two plant species and changes in counts of soil PAH-degrading bacteria and microbial activity. Materials and methods: Alfalfa and tall fescue were grown in monoculture and intercropped for 7 months in contaminated field soil. Soil and plant samples were analyzed for PAHs. Plant biomass, densities of PAH-degradation soil bacteria, soil microbial biomass C and N, enzyme activities, and the physiological profile of the soil microbial community were determined. Results and discussion: Average removal percentage of total PAHs in intercropping (30.5%) was significantly higher than in monoculture (19.9%) or unplanted soil (-0.6%). About 7.5% of 3-ring, 12.3% of 4-ring, and 17.2% of 5(+6)-ring PAHs were removed from the soil by alfalfa, with corresponding values of 25.1%, 10.4%, and 30.1% for tall fescue. Intercropping significantly enhanced the remediation efficiency. About 18.9% of 3-ring, 30.9% of 4-ring, and 33.4% of 5(+6)-ring PAHs were removed by the intercropping system. Higher counts of soil culturable PAH-degrading bacteria and elevated microbial biomass and enzyme activities were found after intercropping. Soil from intercropping showed significantly higher (p < 0.05) average well-color development obtained by the BIOLOG Ecoplate assay and Shannon-Weaver index compared with monoculture. Conclusions: Cropping promoted the dissipation of soil PAHs. Tall fescue gave greater removal of soil PAHs than alfalfa, and intercropping was more effective than monoculture. Intercropping of alfalfa and tall fescue may be a promising in situ bioremediation strategy for PAH-contaminated soils. (orig.)

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

    Science.gov (United States)

    Hudgins, Douglas M.

    2005-01-01

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

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

    Science.gov (United States)

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

    2013-10-15

    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). Copyright © 2013 Elsevier B.V. All rights reserved.

  3. A directional passive air sampler for monitoring polycyclic aromatic hydrocarbons (PAHs) in air mass

    International Nuclear Information System (INIS)

    Tao, S.; Liu, Y.N.; Lang, C.; Wang, W.T.; Yuan, H.S.; Zhang, D.Y.; Qiu, W.X.; Liu, J.M.; Liu, Z.G.; Liu, S.Z.; Yi, R.; Ji, M.; Liu, X.X.

    2008-01-01

    A passive air sampler was developed for collecting polycyclic aromatic hydrocarbons (PAHs) in air mass from various directions. The airflow velocity within the sampler was assessed for its responses to ambient wind speed and direction. The sampler was examined for trapped particles, evaluated quantitatively for influence of airflow velocity and temperature on PAH uptake, examined for PAH uptake kinetics, calibrated against active sampling, and finally tested in the field. The airflow volume passing the sampler was linearly proportional to ambient wind speed and sensitive to wind direction. The uptake rate for an individual PAH was a function of airflow velocity, temperature and the octanol-air partitioning coefficient of the PAH. For all PAHs with more than two rings, the passive sampler operated in a linear uptake phase for three weeks. Different PAH concentrations were obtained in air masses from different directions in the field test. - A novel directional passive air sampler was developed and tested for monitoring PAHs in air masses from different directions

  4. Removal of polycyclic aromatic hydrocarbons (PAHs) from industrial sludges in the ambient air conditions: automotive industry.

    Science.gov (United States)

    Karaca, Gizem; Tasdemir, Yucel

    2013-01-01

    Removal of polycyclic aromatic hydrocarbons (PAHs) existed in automotive industry treatment sludge was examined by considering the effects of temperature, UV, titanium dioxide (TiO2) and diethyl amine (DEA) in different dosages (i.e., 5% and 20%) in this study. Application of TiO2 and DEA to the sludge samples in ambient environment was studied. Ten PAH (Σ10 PAH) compounds were targeted and their average value in the sludge was found to be 4480 ± 1450 ng/g dry matter (DM). Total PAH content of the sludge was reduced by 25% in the ambient air environment. Meteorological conditions, atmospheric deposition, evaporation and sunlight irradiation played an effective role in the variations in PAH levels during the tests carried out in ambient air environment. Moreover, it was observed that when the ring numbers of PAHs increased, their removal rates also increased. Total PAH level did not change with the addition of 5% DEA and only 10% decreased with 5% TiO2 addition. PAH removal ratios were 8% and 32% when DEA (20%) and TiO2 (20%) were added, respectively. It was concluded that DEA was a weak photo-sensitizer yet TiO2 was effective only at 20% dosage.

  5. Monitoring PAH contamination in water: Comparison of biological and physico-chemical tools

    International Nuclear Information System (INIS)

    Bourgeault, A.; Gourlay-Francé, C.

    2013-01-01

    The suitability of biological methods and chemical-based passive samplers to determine exposure to PAHs was tested by deploying zebra mussels and SPMDs along the Seine River over 11 months. The concentration of 13 PAHs was analyzed every month in both water and mussels. The sum of the PAH concentrations in mussels, initially at 299 ng g dry wt −1 , reached 2654, 3972 and 3727 ng g −1 at the end of exposure in the three sampling points taken through the river. The respective SPMD-available concentrations of TPAHs reached 9, 52 and 34 ng L −1 . Results showed seasonal variations of total PAH concentrations in the mussels, characterized by a decrease during spawning. The non-achievement of steady state concentration that was observed in mussels may be accounted for by the temporal variation of environmental concentrations. Thus, a bioaccumulation model based on kinetic rather than simple equilibrium partitioning was found to be more appropriate to describe PAH content in mussels. Moreover, biodynamic kinetic modeling proved useful to better understand the uptake and loss processes of pyrene. It clearly shows that these processes are markedly influenced by the biological state of the zebra mussels. The most realistic hypothesis is that the temporal variation of the biodynamic parameters may originate from a decrease of the mussels' metabolization of PAHs during spawning. Since SPMD passive samplers cannot integrate such biological factors, they are poor predictors of PAH bioavailability in mussels. - Highlights: • PAH contamination was monitored by deploying mussels and SPMDs over 11 months along the Seine River. • 5–6 ring PAHs which could not be quantified in spot samples, were measured in SPMDs. • PAH concentrations in the mussels decreased during spawning. • Temporal variation of bioaccumulated PAH may originate from a decrease of the mussels' metabolism during spawning. • Biodynamic model was allowed to explain the bioaccumulation

  6. Monitoring PAH contamination in water: Comparison of biological and physico-chemical tools

    Energy Technology Data Exchange (ETDEWEB)

    Bourgeault, A., E-mail: bourgeault@ensil.unilim.fr; Gourlay-Francé, C.

    2013-06-01

    The suitability of biological methods and chemical-based passive samplers to determine exposure to PAHs was tested by deploying zebra mussels and SPMDs along the Seine River over 11 months. The concentration of 13 PAHs was analyzed every month in both water and mussels. The sum of the PAH concentrations in mussels, initially at 299 ng g{sub dry} {sub wt}{sup −1}, reached 2654, 3972 and 3727 ng g{sup −1} at the end of exposure in the three sampling points taken through the river. The respective SPMD-available concentrations of TPAHs reached 9, 52 and 34 ng L{sup −1}. Results showed seasonal variations of total PAH concentrations in the mussels, characterized by a decrease during spawning. The non-achievement of steady state concentration that was observed in mussels may be accounted for by the temporal variation of environmental concentrations. Thus, a bioaccumulation model based on kinetic rather than simple equilibrium partitioning was found to be more appropriate to describe PAH content in mussels. Moreover, biodynamic kinetic modeling proved useful to better understand the uptake and loss processes of pyrene. It clearly shows that these processes are markedly influenced by the biological state of the zebra mussels. The most realistic hypothesis is that the temporal variation of the biodynamic parameters may originate from a decrease of the mussels' metabolization of PAHs during spawning. Since SPMD passive samplers cannot integrate such biological factors, they are poor predictors of PAH bioavailability in mussels. - Highlights: • PAH contamination was monitored by deploying mussels and SPMDs over 11 months along the Seine River. • 5–6 ring PAHs which could not be quantified in spot samples, were measured in SPMDs. • PAH concentrations in the mussels decreased during spawning. • Temporal variation of bioaccumulated PAH may originate from a decrease of the mussels' metabolism during spawning. • Biodynamic model was allowed to explain

  7. An external-cavity quantum cascade laser operating near 5.2 µm combined with cavity ring-down spectroscopy for multi-component chemical sensing

    Science.gov (United States)

    Dutta Banik, Gourab; Maity, Abhijit; Som, Suman; Pal, Mithun; Pradhan, Manik

    2018-04-01

    We report on the performance of a widely tunable continuous wave mode-hop-free external-cavity quantum cascade laser operating at λ ~ 5.2 µm combined with cavity ring-down spectroscopy (CRDS) technique for high-resolution molecular spectroscopy. The CRDS system has been utilized for simultaneous and molecule-specific detection of several environmentally and bio-medically important trace molecular species such as nitric oxide, nitrous oxide, carbonyl sulphide and acetylene (C2H2) at ultra-low concentrations by probing numerous rotationally resolved ro-vibrational transitions in the mid-IR spectral region within a relatively small spectral range of ~0.035 cm-1. This continuous wave external-cavity quantum cascade laser-based multi-component CRDS sensor with high sensitivity and molecular specificity promises applications in environmental sensing as well as non-invasive medical diagnosis through human breath analysis.

  8. Molecular and stable carbon isotopic characterization of PAH contaminants at McMurdo Station, Antarctica

    International Nuclear Information System (INIS)

    Kim, Moonkoo . E-mail moonkoo.kim@wmich.edu; Kennicutt, Mahlon C.; Qian Yaorong

    2006-01-01

    The molecular and stable carbon isotopic compositions of contaminant polycyclic aromatic hydrocarbons (PAHs) at McMurdo Station, Antarctica were analyzed in samples collected from land and sub-tidal area. PAHs in the study areas were characterized by high amounts of naphthalene and alkylated naphthalenes from petroleum products introduced by human activities in the area. Principal component analysis (PCA) of PAH composition data identified multiple sources of PAH contamination in the study area. Compositional assignments of origins were confirmed using compound specific stable carbon isotopic analysis

  9. Persistent activation of DNA damage signaling in response to complex mixtures of PAHs in air particulate matter

    Energy Technology Data Exchange (ETDEWEB)

    Jarvis, Ian W.H., E-mail: Ian.Jarvis@ki.se [Institute of Environmental Medicine, Karolinska Institutet, Box 210, SE-171 77 Stockholm (Sweden); Bergvall, Christoffer, E-mail: Christoffer.Bergvall@anchem.su.se [Department of Analytical Chemistry, Stockholm University, Svante Arrhenius väg 16, SE-106 91 Stockholm (Sweden); Bottai, Matteo, E-mail: Matteo.Bottai@ki.se [Institute of Environmental Medicine, Karolinska Institutet, Box 210, SE-171 77 Stockholm (Sweden); Westerholm, Roger, E-mail: Roger.Westerholm@anchem.su.se [Department of Analytical Chemistry, Stockholm University, Svante Arrhenius väg 16, SE-106 91 Stockholm (Sweden); Stenius, Ulla, E-mail: Ulla.Stenius@ki.se [Institute of Environmental Medicine, Karolinska Institutet, Box 210, SE-171 77 Stockholm (Sweden); Dreij, Kristian, E-mail: Kristian.Dreij@ki.se [Institute of Environmental Medicine, Karolinska Institutet, Box 210, SE-171 77 Stockholm (Sweden)

    2013-02-01

    Complex mixtures of polycyclic aromatic hydrocarbons (PAHs) are present in air particulate matter (PM) and have been associated with many adverse human health effects including cancer and respiratory disease. However, due to their complexity, the risk of exposure to mixtures is difficult to estimate. In the present study the effects of binary mixtures of benzo[a]pyrene (BP) and dibenzo[a,l]pyrene (DBP) and complex mixtures of PAHs in urban air PM extracts on DNA damage signaling was investigated. Applying a statistical model to the data we observed a more than additive response for binary mixtures of BP and DBP on activation of DNA damage signaling. Persistent activation of checkpoint kinase 1 (Chk1) was observed at significantly lower BP equivalent concentrations in air PM extracts than BP alone. Activation of DNA damage signaling was also more persistent in air PM fractions containing PAHs with more than four aromatic rings suggesting larger PAHs contribute a greater risk to human health. Altogether our data suggests that human health risk assessment based on additivity such as toxicity equivalency factor scales may significantly underestimate the risk of exposure to complex mixtures of PAHs. The data confirms our previous findings with PAH-contaminated soil (Niziolek-Kierecka et al., 2012) and suggests a possible role for Chk1 Ser317 phosphorylation as a biological marker for future analyses of complex mixtures of PAHs. -- Highlights: ► Benzo[a]pyrene (BP), dibenzo[a,l]pyrene (DBP) and air PM PAH extracts were compared. ► Binary mixture of BP and DBP induced a more than additive DNA damage response. ► Air PM PAH extracts were more potent than toxicity equivalency factor estimates. ► Larger PAHs (> 4 rings) contribute more to the genotoxicity of PAHs in air PM. ► Chk1 is a sensitive marker for persistent activation of DNA damage signaling from PAH mixtures.

  10. Persistent activation of DNA damage signaling in response to complex mixtures of PAHs in air particulate matter

    International Nuclear Information System (INIS)

    Jarvis, Ian W.H.; Bergvall, Christoffer; Bottai, Matteo; Westerholm, Roger; Stenius, Ulla; Dreij, Kristian

    2013-01-01

    Complex mixtures of polycyclic aromatic hydrocarbons (PAHs) are present in air particulate matter (PM) and have been associated with many adverse human health effects including cancer and respiratory disease. However, due to their complexity, the risk of exposure to mixtures is difficult to estimate. In the present study the effects of binary mixtures of benzo[a]pyrene (BP) and dibenzo[a,l]pyrene (DBP) and complex mixtures of PAHs in urban air PM extracts on DNA damage signaling was investigated. Applying a statistical model to the data we observed a more than additive response for binary mixtures of BP and DBP on activation of DNA damage signaling. Persistent activation of checkpoint kinase 1 (Chk1) was observed at significantly lower BP equivalent concentrations in air PM extracts than BP alone. Activation of DNA damage signaling was also more persistent in air PM fractions containing PAHs with more than four aromatic rings suggesting larger PAHs contribute a greater risk to human health. Altogether our data suggests that human health risk assessment based on additivity such as toxicity equivalency factor scales may significantly underestimate the risk of exposure to complex mixtures of PAHs. The data confirms our previous findings with PAH-contaminated soil (Niziolek-Kierecka et al., 2012) and suggests a possible role for Chk1 Ser317 phosphorylation as a biological marker for future analyses of complex mixtures of PAHs. -- Highlights: ► Benzo[a]pyrene (BP), dibenzo[a,l]pyrene (DBP) and air PM PAH extracts were compared. ► Binary mixture of BP and DBP induced a more than additive DNA damage response. ► Air PM PAH extracts were more potent than toxicity equivalency factor estimates. ► Larger PAHs (> 4 rings) contribute more to the genotoxicity of PAHs in air PM. ► Chk1 is a sensitive marker for persistent activation of DNA damage signaling from PAH mixtures.

  11. Polycyclic aromatic hydrocarbons (PAHs) concentration levels, pattern, source identification and soil toxicity assessment in urban traffic soil of Dhanbad, India.

    Science.gov (United States)

    Suman, Swapnil; Sinha, Alok; Tarafdar, Abhrajyoti

    2016-03-01

    Present study was carried out to assess and understand potential health risk and to examine the impact of vehicular traffic on the contamination status of urban traffic soils in Dhanbad City with respect to polycyclic aromatic hydrocarbons (PAHs). Eight urban traffic sites and two control/rural site surface soils were analyzed and the contents of 13 priority PAHs was determined. Total PAH concentration at traffic sites ranged from 1.019 μg g(-1) to 10.856 μg g(-1) with an average value of 3.488 μg g(-1). At control/rural site, average concentration of total PAHs was found to be 0.640 μg g(-1). PAH pattern was dominated by four- and five-ring PAHs (contributing >50% to the total PAHs) at all the eight traffic sites. On the other hand, rural soil showed a predominance of low molecular weight three-ring PAHs (contributing >30% to the total PAHs). Indeno[123-cd]pyrene/benz[ghi]perylene (IP/BgP) ratio indicated that PAH load at the traffic sites is predominated by the gasoline-driven vehicles. The ratio of Ant/(Ant+Phe) varied from 0.03 to 0.44, averaging 0.10; Fla/(Fla+Pyr) from 0.39 to 0.954, averaging 0.52; BaA/(BaA+Chry) from 0.156 to 0.60, averaging 0.44; and IP/(IP+BgP) from 0.176 to 0.811, averaging 0.286. The results indicated that vehicular emission was the major source for PAHs contamination with moderate effect of coal combustion and biomass combustion. Carcinogenic potency of PAH load in traffic soil was nearly 6.15 times higher as compared to the control/rural soil. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. PAHs in Translucent Interstellar Clouds

    Science.gov (United States)

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

    2011-05-01

    We discuss the proposal of relating the origin of some of the diffuse interstellar bands (DIBs) to neutral polycyclic aromatic hydrocarbons (PAHs) present in translucent interstellar clouds. The spectra of several cold, isolated gas-phase PAHs have been measured in the laboratory under experimental conditions that mimic the interstellar conditions and are compared with an extensive set of astronomical spectra of reddened, early type stars. This comparison provides - for the first time - accurate upper limits for the abundances of specific PAH molecules along specific lines-of-sight. Something that is not attainable from IR observations alone. The comparison of these unique laboratory data with high resolution, high S/N ratio astronomical observations leads to two major findings: (1) a finding specific to the individual molecules that were probed in this study and, which leads to the clear and unambiguous conclusion that the abundance of these specific neutral PAHs must be very low in the individual translucent interstellar clouds that were probed in this survey (PAH features remain below the level of detection) and, (2) a general finding that neutral PAHs exhibit intrinsic band profiles that are similar to the profile of the narrow DIBs indicating that the carriers of the narrow DIBs must have close molecular structure and characteristics. This study is the first quantitative survey of neutral PAHs in the optical range and it opens the way for unambiguous quantitative searches of PAHs in a variety of interstellar and circumstellar environments. // Reference: F. Salama et al. (2011) ApJ. 728 (1), 154 // Acknowledgements: F.S. acknowledges the support of the NASA's Space Mission Directorate APRA Program. J.K. acknowledges the financial support of the Polish State (grant N203 012 32/1550). The authors are deeply grateful to the ESO archive as well as to the ESO staff members for their active support.

  13. Polycyclic aromatic hydrocarbons (PAHs) biodegradation potential and diversity of microbial consortia enriched from tsunami sediments in Miyagi, Japan.

    Science.gov (United States)

    Bacosa, Hernando Pactao; Inoue, Chihiro

    2015-01-01

    The Great East Japan Earthquake caused tsunamis and resulted in widespread damage to human life and infrastructure. The disaster also resulted in contamination of the environment by chemicals such as polycyclic aromatic hydrocarbons (PAHs). This study was conducted to investigate the degradation potential and describe the PAH-degrading microbial communities from tsunami sediments in Miyagi, Japan. PAH-degrading bacteria were cultured by enrichment using PAH mixture or pyrene alone as carbon and energy sources. Among the ten consortia tested for PAH mixture, seven completely degraded fluorene and more than 95% of phenanthrene in 10 days, while only four consortia partially degraded pyrene. Six consortia partially degraded pyrene as a single substrate. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) revealed that each sample was dominated by unique microbial populations, regardless of sampling location. The consortia were dominated by known PAHs degraders including Sphingomonas, Pseudomonas, and Sphingobium; and previously unknown degraders such as Dokdonella and Luteimonas. A potentially novel and PAH-degrading Dokdonella was detected for the first time. PAH-ring hydroxylating dioxygenase (PAH-RHDα) gene was shown to be more effective than nidA in estimating pyrene-degrading bacteria in the enriched consortia. The consortia obtained in this study are potential candidates for remediation of PAHs contaminated soils. Copyright © 2014 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

    Kasumba, John; Holmén, Britt A.

    2018-02-01

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

  15. Token ring technology report

    CERN Document Server

    2013-01-01

    Please note this is a Short Discount publication. This report provides an overview of the IBM Token-Ring technology and products built by IBM and compatible vendors. It consists of two sections: 1. A summary of the design trade-offs for the IBM Token-Ring. 2. A summary of the products of the major token-ring compatible vendors broken down by adapters and components, wiring systems, testing, and new chip technology.

  16. Tests of an environmental and personnel safe cleaning process for Brookhaven National Laboratory accelerator and storage ring components

    International Nuclear Information System (INIS)

    Foerster, C.L.; Lanni, C.; Lee, R.; Mitchell, G.; Quade, W.

    1997-01-01

    A large measure of the successful operation of the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory (BNL) for over a decade can be attributed to the cleaning of its ultrahigh vacuum (UHV) components during and after construction. A new UHV cleaning process, which has to be environmentally and personnel safe, is needed to replace the harsh, unfriendly process which is still in use. Dow Advanced Cleaning Systems was contracted to develop a replacement process without the use of harsh chemicals and which must clean vacuum surfaces as well as the existing process. Acceptance of the replacement process was primarily based on photon stimulated desorption (PSD) measurements of beam tube samples run on NSLS beam line U10B. One meter long beam tube samples were fabricated from aluminum, 304 stainless steel, and oxygen-free copper. Initially, coupon samples were cleaned and passed preliminary testing for the proposed process. Next, beam tube samples of each material were cleaned, and the PSD measured on beam line U10B using white light with a critical energy of 487 eV. Prior to cleaning, the samples were contaminated with a mixture of cutting oils, lubricants, vacuum oils, and vacuum grease. The contaminated samples were then baked. Samples of each material were also cleaned with the existing process after the same preparation. Beam tube samples were exposed to between 10 22 and 10 23 photons per meter for a PSD measurement. Desorption yields for H 2 , CO, CO 2 , CH 4 , and H 2 O are reported for both the existing cleaning and for the replacement cleaning process. Preliminary data, residual gas scans, and PSD results are given and discussed. The new process is also compared with new cleaning methods developed in other laboratories. After modification, the new UHV cleaning process was accepted by BNL

  17. Distribution and health risks of polycyclic aromatic hydrocarbons (PAHs) in smoke aerosols from burning of selected garden wastes

    International Nuclear Information System (INIS)

    Hui, Tay Joo; Seng, Tan Hock; Mohd Radzi Abas; Norhayati Mohd Tahir

    2008-01-01

    A study has been carried out to characterize polycyclic aromatic hydrocarbons emitted from the burning of five types of typical garden wastes viz, Bachang, Mango, Jackfruit, Jambu Air litter fall and a type of Grass. The samples were burned to the ember and respective smoke aerosols emitted during the burning period were sampled using high volume filtration on a pre-cleaned glass fibre filters. Polycyclic aromatic hydrocarbons (PAHs) were extracted using dichloromethane-methanol (3:1) as solvent and the extracts fractionated on silica-alumina column. Detection and quantification of PAHs compounds were carried out using GC-MS. Results indicated that burning resulted in the formation of significant amount of PAHs compounds in all samples; total PAHs compounds emitted were in the range of 0.41 to 42.2 μg/ m 3 . The major PAHs compound exhibited in all smoke samples were three to four rings PAHs (example fluoranthene and pyrene) with lesser amount of five to six rings (example benzo(a)pyrene and benzo(g,h,i) perylene) and two rings PAHs (example acenaphthylene). The BaP equivalency results showed that the potential health risk from these garden wastes smoke were very significant; total BaP equivalency values were in the range of 5.60 E+04 pg/ m 3 - 4.98 E+06 pg/ m 3 with Jambu Air smoke exhibited the highest potential health risk. (author)

  18. PAH Baselines for Amazonic Surficial Sediments: A Case of Study in Guajará Bay and Guamá River (Northern Brazil).

    Science.gov (United States)

    Rodrigues, Camila Carneiro Dos Santos; Santos, Ewerton; Ramos, Brunalisa Silva; Damasceno, Flaviana Cardoso; Correa, José Augusto Martins

    2018-06-01

    The 16 priority PAH were determined in sediment samples from the insular zone of Guajará Bay and Guamá River (Southern Amazon River mouth). Low hydrocarbon levels were observed and naphthalene was the most representative PAH. The low molecular weight PAH represented 51% of the total PAH. Statistical analysis showed that the sampling sites are not significantly different. Source analysis by PAH ratios and principal component analysis revealed that PAH are primary from a few rate of fossil fuel combustion, mainly related to the local small community activity. All samples presented no biological stress or damage potencial according to the sediment quality guidelines. This study discuss baselines for PAH in surface sediments from Amazonic aquatic systems based on source determination by PAH ratios and principal component analysis, sediment quality guidelines and through comparison with previous studies data.

  19. Distribution, sources and ecological risk assessment of PAHs in surface sediments from the Luan River Estuary, China.

    Science.gov (United States)

    Zhang, Daolai; Liu, Jinqing; Jiang, Xuejun; Cao, Ke; Yin, Ping; Zhang, Xunhua

    2016-01-15

    The distribution, sources and risk assessment of 16 polycyclic aromatic hydrocarbons (PAHs) of surface sediments in the Luan River Estuary, China, have been investigated in the research. The results indicated that the total concentrations of 16 PAHs in surface sediments of the Luan River Estuary ranged from 5.1 to 545.1 ng g(-1)dw with a mean value of 120.8 ng g(-1)dw, which is relatively low in comparison with other estuaries around the world. The PAHs in the study area were mainly originated from pyrogenic sources. Besides, PAHs may be contaminated by petrogenic PAHs as indicated by the selected ratios of PAHs, the 2-tailed Pearson correlation analysis and principal components analysis at different sites. The result of the ecological risk assessment shows little negative effect for most individual PAHs in surface sediments of the Luan River Estuary, China. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

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

    2016-07-01

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

  1. Concentration and source identification of polycyclic aromatic hydrocarbons (PAHs) in PM10 of urban, industrial and semi-urban areas in Malaysia

    Science.gov (United States)

    Jamhari, Anas Ahmad; Sahani, Mazrura; Latif, Mohd Talib; Chan, Kok Meng; Tan, Hock Seng; Khan, Md Firoz; Mohd Tahir, Norhayati

    2014-04-01

    Particulate matter (PM10) associated with polycyclic aromatic hydrocarbons (PAHs) in ambient air were determined at two sites within the Klang Valley, Kuala Lumpur (urban, KL) and Petaling Jaya (industrial, PJ), and one site outside the Klang Valley, Bangi (semi-urban, BG). This study aimed to determine the concentration and distribution of PAHs in PM10 and the source of origin through principal component analysis (PCA) and diagnostic ratio analysis. This study also assessed the health risk from exposure to airborne BaPeq. PM10 samples were collected on glass fiber filter paper using a High Volume Sampler (HVS) for 24 h between September 2010 and April 2011. The filter papers with PM10 were extracted using dichloromethane-methanol (3:1), and analysis of 16 USEPA priority PAHs was determined using gas chromatography with mass spectra (GC-MS). Health risk assessment was estimated using toxic equivalency factors (TEFs) and incremental lifetime cancer risk (ILCR) which quantitatively estimate the exposure risk for age specific group. The results showed that the total PAHs concentrations throughout seasonal monsoons for KL, PJ and BG ranged from 1.33 ng m-3 to 2.97 ng m-3, 2.24 ng m-3 to 4.84 ng m-3 and 1.64 ng m-3 to 3.45 ng m-3 respectively. More than 80% of total PAHs consisted of 5-ring and 6-ring PAHs such as benzo[a]pyrene (BaP), indeno[1,2,3-cd]pyrene (IcP), benzo[b]fluoranthene (BbF), benzo[k]fluoranthene (BkF) and benzo[g,h,i]perylene (BgP). The presence of benzo[g,h,i]perylene (BgP) with high concentration at all locations suggested a source indicator for traffic emission. PCA and diagnostic ratio analysis also suggested substantial contributions from traffic emission with minimal influence from coal combustion and natural gas emissions. The use of total BaPeq concentration provide a better estimation of carcinogenicity activities, where they contributed to more than 50% of the potential health risk. Health risk assessment showed that the estimated incremental

  2. Ancient water bottle use and polycyclic aromatic hydrocarbon (PAH) exposure among California Indians: a prehistoric health risk assessment.

    Science.gov (United States)

    Sholts, Sabrina B; Smith, Kevin; Wallin, Cecilia; Ahmed, Trifa M; Wärmländer, Sebastian K T S

    2017-06-23

    Polycyclic aromatic hydrocarbons (PAHs) are the main toxic compounds in natural bitumen, a fossil material used by modern and ancient societies around the world. The adverse health effects of PAHs on modern humans are well established, but their health impacts on past populations are unclear. It has previously been suggested that a prehistoric health decline among the native people living on the California Channel Islands may have been related to PAH exposure. Here, we assess the potential health risks of PAH exposure from the use and manufacture of bitumen-coated water bottles by ancient California Indian societies. We replicated prehistoric bitumen-coated water bottles with traditional materials and techniques of California Indians, based on ethnographic and archaeological evidence. In order to estimate PAH exposure related to water bottle manufacture and use, we conducted controlled experiments to measure PAH contamination 1) in air during the manufacturing process and 2) in water and olive oil stored in a completed bottle for varying periods of time. Samples were analyzed with gas chromatography/mass spectrometry (GC/MS) for concentrations of the 16 PAHs identified by the US Environmental Protection Agency (EPA) as priority pollutants. Eight PAHs were detected in concentrations of 1-10 μg/m 3 in air during bottle production and 50-900 ng/L in water after 2 months of storage, ranging from two-ring (naphthalene and methylnaphthalene) to four-ring (fluoranthene) molecules. All 16 PAHs analyzed were detected in olive oil after 2 days (2 to 35 μg/kg), 2 weeks (3 to 66 μg/kg), and 2 months (5 to 140 μg/kg) of storage. For ancient California Indians, water stored in bitumen-coated water bottles was not a significant source of PAH exposure, but production of such bottles could have resulted in harmful airborne PAH exposure.

  3. Accumulation, allocation, and risk assessment of polycyclic aromatic hydrocarbons (PAHs in soil-Brassica chinensis system.

    Directory of Open Access Journals (Sweden)

    Juan Zhang

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

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

    International Nuclear Information System (INIS)

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

    2016-01-01

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

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

    Science.gov (United States)

    Zhang, Xincheng; Wang, Weiyu; Zhu, Xianlei

    2017-04-01

    with the contribution of 20% - 40%. After the implementation of Beijing 2013 Clean Air Action Plan, the proportion of low-ring PAHs, tracers of coal combustion, decreased, reflecting the positive impact of policy. The mechanism of PAHs dry deposition mechanism was different from that of airborne particulate matter (PM). Dry deposition of PAHs in PM with aerodynamic diameter 10.2μm was responsible for, respectively, 45% and 23% of PAHs in dustfall, and caused seasonal variability of PAHs dry deposition. Key words: dry deposition; PAHs; suburban area; source; environmental effects; health risk Acknowledgments: The study has been supported by Beijing Excellent Talents Project of the year of 2012 (No.2012D009051000001) and by National Science Foundation (No.41175102) *Corresponding author: Xianlei Zhu e-mail: zhuxl@cup.edu.cn)

  6. Polycyclic aromatic hydrocarbons (PAHs) in wetland soils under different land uses in a coastal estuary: toxic levels, sources and relationships with soil organic matter and water-stable aggregates.

    Science.gov (United States)

    Xiao, Rong; Bai, Junhong; Wang, Junjing; Lu, Qiongqiong; Zhao, Qingqing; Cui, Baoshan; Liu, Xinhui

    2014-09-01

    The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) were determined in the soils from industrial, wharf, cropland, milldam and natural wetland sites to characterize their distributions, toxic levels and possible sources in the Pearl River Estuary and identify their relationships with soil organic matter (SOM) and water-stable aggregates (WSAs). Our results indicate that the average concentration of total PAHs in this region reached a moderate pollution level, which was higher than that in other larger estuaries in Asia. The average level of total PAHs in industrial soils was 1.2, 1.5, 1.6 and 2.3 times higher than those in soils from wharf, cropland, milldam and natural wetland sites, respectively. Greater accumulation of PAHs occurred in the middle and/or bottom soil layers where 3-ring PAHs were dominant. Industrial soils also exhibited the highest toxic levels with the highest toxic equivalent concentrations of PAHs, followed by wharf and milldam soils, and the cropland and wetland soils had the lowest toxicity. The diagnostic ratios suggested that PAHs primarily originated from biomass and coal combustion at industrial and milldam sites, and petroleum combustion was determined to be the primary source of PAHs at the wharf, cropland and wetland sites. Both 3-ring and 4-ring PAHs in the milldam and wharf soils were significantly positively correlated with the SOM, whereas the 4,5,6-ring PAHs and total PAHs in industrial soils and the 2-ring PAHs in cropland soils were significantly negatively correlated with the SOM. In addition, large WSAs also exhibited a significant positive correlation with PAHs. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Black rings

    International Nuclear Information System (INIS)

    Emparan, Roberto; Reall, Harvey S

    2006-01-01

    A black ring is a five-dimensional black hole with an event horizon of topology S 1 x S 2 . We provide an introduction to the description of black rings in general relativity and string theory. Novel aspects of the presentation include a new approach to constructing black ring coordinates and a critical review of black ring microscopics. (topical review)

  8. On arbitrarily graded rings

    Indian Academy of Sciences (India)

    58

    paper is devoted to the study of arbitrary rings graded through arbitrary sets. .... which recover certain multiplicative relations among the homogeneous components ... instance the case in which the grading set A is an Abelian group, where the ...

  9. White Ring; White ring

    Energy Technology Data Exchange (ETDEWEB)

    Aoki, H.; Yuzawa, H. [Nikken Sekkei Ltd., Osaka (Japan)

    1998-01-05

    White Ring is a citizen`s gymnasium used for figure skating and short track speed skating games of 18th Winter Olympic Games in 1998. White Ring is composed of a main-arena and a sub-arena. For the main-arena with an area 41mtimes66m, an ice link can be made by disengaging the potable floor and by flowing brine in the bridged polystyrene pipes embedded in the concrete floor. Due to the fortunate groundwater in this site, well water is used for the outside air treatment energy in 63% during heating and in 35% during cooling. Ammonia is used as a cooling medium for refrigerating facility. For the heating of audience area in the large space, heat load from the outside is reduced by enhancing the heat insulation performance of the roof of arena. The audience seats are locally heated using heaters. For the White Ring, high quality environment is realized for games through various functions of the large-scale roof of the large space. Success of the big event was expected. 15 figs., 4 tabs.

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

    Science.gov (United States)

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

    2013-05-01

    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. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Optimization of Large Volume Injection for Improved Detection of Polycyclic Aromatic Hydrocarbons (PAH) in Mussels

    DEFF Research Database (Denmark)

    Duedahl-Olesen, Lene; Ghorbani, Faranak

    2008-01-01

    Detection of PAH of six benzene rings is somewhat troublesome and lowering the limits of detection (LODs) for these compounds in food is necessary. For this purpose, we optimized a Programmable-Temperature-Vaporisation (PTV) injection with Large Volume Injection (LVI) with regard to the GC-MS det...

  12. PAH in tea and coffee

    DEFF Research Database (Denmark)

    Duedahl-Olesen, Lene; Navarantem, Marin; Adamska, Joanna

    For food regulation in the European Union maximum limits on other foods than tea and coffee includes benzo[a]pyrene and the sum of PAH4 (sum of benzo[a]pyrene, chrysene, benz[a]anthracene and benzo[b]fluoranthene). This study includes analysis of the above mentioned PAH in both, tea leaves, coffee...... beans and ready-to-drink preparations. Compared to other food matrices (e.g. fish), the analytical methods were challenged by the hot water extracts. Preparation of tea includes roasting and drying of the tea leaves using combustion gases from burning wood, oil, or coal. These are responsible...... for accumulation of PAH in tea leaves. Different varieties of tea leaves were analyzed and highest concentrations were found in leaves from mate and black tea with maximum concentrations of 32 μg/kg for benzo[a]pyrene and 115 μg/kg for the sum of PAH4. Also, coffee beans are roasted during processing. However...

  13. Decontamination of PAH polluted soils by fungi. Subproject: PAH degradation balance and testing of the extended laboratory process. Final report

    International Nuclear Information System (INIS)

    Martens, R.; Zadrazil, F.; Wolter, M.; Bahadir, M.

    1997-01-01

    The aim of the research project was first to select a fungus with a high potential for mineralization of polycyclic aromatic hydrocarbons (PAH) and a good ability to colonize different soils. The application of this fungus for a degradation of PAH in soil had to be tested. In a screening of 57 white rot fungi the fungus Pleurotus sp. Florida fulfilled these requirements best. In pure culture it was able to metabolize and mineralize highly condensed 4-6 ring PAH to a great extent. For instance, up to 50% of 14 C-pyrene or 39% of 14 C-benzo(a)pyrene was mineralized to 14 CO 2 within 15 weeks. If different carriers for 14 C-pyrene were used the mineralization correlated with the bioavailability, which was characterized by the desorption of the compound from the carriers with water. The mineralization of 14 C-pyrene, 14 C-benz(a)anthracene; 14 C-benzo(a)-pyrene and 14 C-dibenz(a, h)anthracene in native soils showed that a colonization with Pl. sp Florida inhibited the degradation of the less recalcitrant 14 C-pyrene by the indigenous soil microflora. However, the mineralization of the carcinogenic, very recalcitrant and high condensed 14 C-PAH was considerably supported by the fungus. Therefore this capabilities of the fungus could not be proven in a joint medium-scale soil experiment (0.8 m 3 soil) which had been conducted within a parmership with scientists in Jena and an industriell firm. Because of safety aspects only the low condensed less recalcitrant PAH could be applied in this experiment. (orig./MG) [de

  14. Determination of polycyclic aromatic hydrocarbons (PAHs). gas chromatographic method; Determinazione degli idrocarburi policiclici aromatici (IPA). Metodo gascaromatografico

    Energy Technology Data Exchange (ETDEWEB)

    Menichini, E; Viviano, G [Istituto Superiore di Sanita` , Rome (Italy). Lab. di Igiene Ambientale

    1997-12-01

    The method enables the determination of 4- to 6- ring PAHs and particularly of carcinogenic PAHs regulated in Italy. This revision is based on the results of a national collaborative study. Sample extract, obtained by a method described in a previous report (Rapporto ISTISAN: 90/33) is cleaned up by thin layer chromatography and analysed by gas chromatography; identification is confirmed by mass spectrometry. An intralaboratory quality control program is described.

  15. Source identification and ecological impact evaluation of PAHs in urban river sediments: A case study in Taiwan.

    Science.gov (United States)

    Tu, Y T; Ou, J H; Tsang, D C W; Dong, C D; Chen, C W; Kao, C M

    2018-03-01

    The Love River and Ho-Jin River, two major urban rivers in Kaohsiung City, Taiwan, are moderately to heavily polluted because different types of improperly treated wastewaters are discharged into the rivers. In this study, sediment and river water samples were collected from two rivers to investigate the river water quality and accumulation of polycyclic aromatic hydrocarbons (PAHs) in sediments. The spatial distribution, composition, and source appointment of PAHs of the sediments were examined. The impacts of PAHs on ecological system were assessed using toxic equivalence quotient (TEQ) of potentially carcinogenic PAHs (TEQ carc ) and sediment quality guidelines. The average PAHs concentrations ranged from 2161 ng/g in Love River sediment to 160 ng/g in Ho-Jin River sediment. This could be due to the fact that Love River Basin had much higher population density and pyrolytic activities. High-ring PAHs (4-6 rings) contributed to 59-90% of the total PAHs concentrations. Benzo(a)pyrene (BaP) had the highest toxic equivalence quotient (up to 188 ng TEQ/g). Moreover, the downstream sediments contained higher TEQ of total TPHs than midstream and upstream sediment samples. The PAHs were adsorbed onto the fine particles with high organic content. Results from diagnostic ratio analyses indicate that the PAHs in two urban river sediments might originate from oil/coal combustion, traffic-related emissions, and waste combustion (pyrogenic activities). Future pollution prevention and management should target the various industries, incinerators, and transportation emission in this region to reduce the PAHs pollution. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

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

    2014-02-01

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

  17. Vortex rings

    CERN Document Server

    Akhmetov, D G

    2009-01-01

    This text on vortex rings covers their theoretical foundation, systematic investigations, and practical applications such as the extinction of fires at gushing oil wells. It pays special attention to the formation and motion of turbulent vortex rings.

  18. Sources of polyaromatic hydrocarbons (PAH); Kildebestemmelse af polyaromatiske kulbrinter (PAH)

    Energy Technology Data Exchange (ETDEWEB)

    Egsgaard, H. [Forskningscenetr Risoe, Ald. for Plantebiologi og Biokemi (DK); Larsen, E. [Forskningscenter Risoe, Ald. for Optic og Fluid Dynamik (Denmark)

    2000-03-01

    Aromatic hydrocarbons including PAH compounds are thermally and chemically very stable compounds and are formed by gasification/pyrolysis of biomass. With reference to the tar compounds present in the produced gas from updraft gasifiers the sources responsible for the formation of naphthalene and poly-aromatic hydrocarbons have been investigated. The focus has been on thermal and oxidative conversions of compounds related to the lignin building blocks. Thus, phenols, 2-methoxy-phenols and 4-substituted-2-methoxy-phenols were investigated by introducing water solutions of the compounds into a continuos flow system operating in the temperature range 600-850 deg. C. The pyrolysis products were identified by GC/MS. The tar compounds reveal a well-defined and characteristic thermal transformation. Phenol is a strong source to naphthalene and indenes while 2-methoxyphenols are sources to aromatic oxo-compounds such as cinnamaldehyde. More complex systems are sources to higer PAH compounds. Thus, oligomers of phenol and 2-methoxyphenol give dibenzofuran and oligomers of isoeugenol are important sources to acenaphthylene. It is characteristic that the simple tar compounds investigated undergo loss of CO and hereby loss of the aromatic structure. The intermediary compounds are very reactive cyclo-pentadienes entering Diels-Alder reactions. The later products are transformed to aromatic compounds. The results may facilitate the determination of optimum conditions for updraft gasifiers and hence a reduction of PAH formation. (au)

  19. Biological treatment of PAH-contaminated sediments in a Sequencing Batch Reactor

    International Nuclear Information System (INIS)

    Chiavola, Agostina; Baciocchi, Renato; Gavasci, Renato

    2010-01-01

    The technical feasibility of a sequential batch process for the biological treatment of sediments contaminated by polycyclic aromatic hydrocarbons (PAHs) was evaluated through an experimental study. A bench-scale Sediment Slurry Sequencing Batch Reactor (SS-SBR) was fed with river sediments contaminated by a PAH mixture made by fluorene, anthracene, pyrene and crysene. The process performance was evaluated under different operating conditions, obtained by modifying the influent organic load, the feed composition and the hydraulic residence time. Measurements of the Oxygen Uptake Rates (OURs) provided useful insights on the biological kinetics occurring in the SS-SBR, suggesting the minimum applied cycle time-length of 7 days could be eventually halved, as also confirmed by the trend observed in the volatile solid and total organic carbon data. The removal efficiencies gradually improved during the SS-SBR operation, achieving at the end of the study rather constant removal rates above 80% for both 3-rings PAHs (fluorene and anthracene) and 4-ring PAHs (pyrene and crysene) for an inlet total PAH concentration of 70 mg/kg as dry weight (dw).

  20. Internal versus external fixation of the anterior component in unstable fractures of the pelvic ring: pooled results from a systematic review.

    Science.gov (United States)

    Wardle, B; Eslick, G D; Sunner, P

    2016-10-01

    Improving reduction of the pelvic ring improves long-term functional outcomes for patients. It has been demonstrated that posterior internal fixation is necessary to adequately control fractures to the posterior ring and there is evidence that supplementing this with fixation of the anterior ring improves stability. It is accepted that internal fixation provides greater stability than external fixation of the anterior ring but long-term differences in radiographic and functional outcomes have not yet been quantified. A search of electronic databases, reference lists and review articles from 1989 to 2015 yielded 18 studies (n = 884) that met our inclusion criteria. We included studies that discussed pelvic ring injuries in adults, reported functional or radiological outcomes or complications by anterior ring intervention and exceeded 14 patients. We excluded biomechanical and cadaver studies. Internal fixation of the anterior pelvic ring had better functional and radiographic outcomes. Residual displacement of >10 mm was less common with internal fixation (ER 0.12, 95 % CI 0.06-0.24) than external fixation (ER 0.31, 95 % CI 0.11-0.62). Unsatisfactory outcomes also occurred at a lower rate (ER 0.09, 95 % CI 0.03-0.22) compared to external fixation (ER 0.32, 95 % CI 0.18-0.50). Losses of reduction (ER 0.02, 95 % CI 0.01-0.04 versus ER 0.07, 95 % CI 0.02-0.21), malunions (ER 0.03, 95 % CI 0.01-0.08 versus ER 0.07, 95 % CI 0.02-0.21) and delayed/non-unions (ER 0.02, 95 % CI 0.01-0.05 versus ER 0.04, 95 % CI 0.02-0.07). Internal fixation of the anterior pelvic ring as supplementary fixation for unstable injuries to the pelvic ring appears to result in better radiographic and functional outcomes as well as fewer complications. However, data that separated outcomes and complications in relation to interventions of the anterior pelvic ring were limited. More studies looking specifically at outcomes in relation to the type of anterior ring intervention are

  1. PAH contamination in soils adjacent to a coal-transporting facility in Tapin district, south Kalimantan, Indonesia.

    Science.gov (United States)

    Mizwar, Andy; Trihadiningrum, Yulinah

    2015-07-01

    This study was undertaken to determine the level of 16 polycyclic aromatic hydrocarbon (PAH), listed as priority pollutants by the United States Environmental Protection Agency (USEPA), in surface soils around a coal-transporting facility in the western part of South Kalimantan, Indonesia. Three composite soil samples were collected from a coal stockpile, coal-hauling road, and coal port. Identification and quantification of PAH was performed by gas chromatography-mass spectrometry. The total content of 16 USEPA-PAH ranged from 11.79 to 55.30 mg/kg with arithmetic mean value of 33.14 mg/kg and median of 32.33 mg/kg. The 16 USEPA-PAH measured levels were found to be greater compared with most of the literature values. The levels of high molecular-weight PAH (5- and 6-ring) were dominant and formed 67.77-80.69 % of the total 16 USEPA-PAH The most abundant of individual PAH are indeno[1,2,3-cd] pyrene and benzo[a]pyrene with concentration ranges of 2.11-20.56 and 1.59-17.84 mg/kg, respectively. The degree of PAH contamination and subsequent toxicity assessment suggest that the soils of the study area are highly contaminated and pose a potential health risk to humans.

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

    Science.gov (United States)

    Minick, D James; Anderson, Kim A

    2017-09-01

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

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

    Science.gov (United States)

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

    2014-09-01

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

  4. PAH EMISSION AT THE BRIGHT LOCATIONS OF PDRs: THE grandPAH HYPOTHESIS

    International Nuclear Information System (INIS)

    Andrews, H.; Tielens, A. G. G. M.; Boersma, C.; Allamandola, L. J.; Werner, M. W.; Livingston, J.

    2015-01-01

    The polycyclic aromatic hydrocarbon (PAH) emission observed in the Spitzer Infrared Spectrograph spectra of bright mid-IR locations of NGC 7023, NGC 2023, and NGC 1333 was analyzed. These objects show large variations in PAH band ratios when studied through spectral mapping. Nevertheless, the mid-IR spectra at these bright spots show a remarkably similar PAH emission. We used the NASA Ames PAH IR Spectroscopic Database to fit the observations and analyze the derived PAH populations. Our results show that PAH emission in the 5–15 μm range appears to be rather insensitive to variations of the radiation field. Similar PAH populations of neutral small to medium-sized PAHs (∼50%), with ionized species contributing in slightly less than 50%, provide very good fits. Analyzing the degeneracy of the results shows that subtle (but intrinsic) variations in the emission properties of individual PAHs lead to observable differences in the resulting spectra. On top of this, we found that variations of <30% in the PAH abundances would lead to noticeable spectral differences between the three photodissociation regions (PDRs). Therefore, PAH populations must be remarkably similar at these different lines of sight. To account for this, we suggest the concept of grandPAHs as a unique mixture of the most stable PAHs emitting at these spots. Using NGC 7023 as an example, the grandPAHs refer to the robust PAH population that results from the intense processing of PAHs at the border limit between the PDR and the molecular cloud, where, due to the UV radiation that destroys the PAH population, the abundance of PAHs starts decreasing as we move toward the star

  5. PAH EMISSION AT THE BRIGHT LOCATIONS OF PDRs: THE grandPAH HYPOTHESIS

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, H.; Tielens, A. G. G. M. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Boersma, C.; Allamandola, L. J. [NASA Ames Research Center, MS 245-6, Moffett Field, CA 94035 (United States); Werner, M. W.; Livingston, J., E-mail: heandrew@strw.leidenuniv.nl, E-mail: Christiaan.Boersma@nasa.gov [Jet Propulsion Laboratory, MC 264-767, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)

    2015-07-01

    The polycyclic aromatic hydrocarbon (PAH) emission observed in the Spitzer Infrared Spectrograph spectra of bright mid-IR locations of NGC 7023, NGC 2023, and NGC 1333 was analyzed. These objects show large variations in PAH band ratios when studied through spectral mapping. Nevertheless, the mid-IR spectra at these bright spots show a remarkably similar PAH emission. We used the NASA Ames PAH IR Spectroscopic Database to fit the observations and analyze the derived PAH populations. Our results show that PAH emission in the 5–15 μm range appears to be rather insensitive to variations of the radiation field. Similar PAH populations of neutral small to medium-sized PAHs (∼50%), with ionized species contributing in slightly less than 50%, provide very good fits. Analyzing the degeneracy of the results shows that subtle (but intrinsic) variations in the emission properties of individual PAHs lead to observable differences in the resulting spectra. On top of this, we found that variations of <30% in the PAH abundances would lead to noticeable spectral differences between the three photodissociation regions (PDRs). Therefore, PAH populations must be remarkably similar at these different lines of sight. To account for this, we suggest the concept of grandPAHs as a unique mixture of the most stable PAHs emitting at these spots. Using NGC 7023 as an example, the grandPAHs refer to the robust PAH population that results from the intense processing of PAHs at the border limit between the PDR and the molecular cloud, where, due to the UV radiation that destroys the PAH population, the abundance of PAHs starts decreasing as we move toward the star.

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

    Science.gov (United States)

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

    2016-04-01

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

  7. Biodegradation of aged polycyclic aromatic hydrocarbons (PAHs) by microbial consortia in soil and slurry phases.

    Science.gov (United States)

    Li, Xiaojun; Li, Peijun; Lin, Xin; Zhang, Chungui; Li, Qi; Gong, Zongqiang

    2008-01-15

    Microbial consortia isolated from aged oil-contaminated soil were used to degrade 16 polycyclic aromatic hydrocarbons (15.72 mgkg(-1)) in soil and slurry phases. The three microbial consortia (bacteria, fungi and bacteria-fungi complex) could degrade polycyclic aromatic hydrocarbons (PAHs), and the highest PAH removals were found in soil and slurry inoculated with fungi (50.1% and 55.4%, respectively). PAHs biodegradation in slurry was lower than in soil for bacteria and bacteria-fungi complex inoculation treatments. Degradation of three- to five-ring PAHs treated by consortia was observed in soil and slurry, and the highest degradation of individual PAHs (anthracene, fluoranthene, and benz(a)anthracene) appeared in soil (45.9-75.5%, 62-83.7% and 64.5-84.5%, respectively) and slurry (46.0-75.8%, 50.2-86.1% and 54.3-85.7%, respectively). Therefore, inoculation of microbial consortia (bacteria, fungi and bacteria-fungi complex) isolated from in situ contaminated soil to degrade PAHs could be considered as a successful method.

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

    Science.gov (United States)

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

    2018-02-01

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

  9. The ir emission features: Emission from PAH (Polycyclic Aromatic Hydrocarbons) molecules and amorphous carbon particles

    Energy Technology Data Exchange (ETDEWEB)

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

    1986-01-01

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

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

    International Nuclear Information System (INIS)

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

    1986-01-01

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

  11. Interstellar dehydrogenated PAH anions: vibrational spectra

    Science.gov (United States)

    Buragohain, Mridusmita; Pathak, Amit; Sarre, Peter; Gour, Nand Kishor

    2018-03-01

    Interstellar polycyclic aromatic hydrocarbon (PAH) molecules exist in diverse forms depending on the local physical environment. Formation of ionized PAHs (anions and cations) is favourable in the extreme conditions of the interstellar medium (ISM). Besides in their pure form, PAHs are also likely to exist in substituted forms; for example, PAHs with functional groups, dehydrogenated PAHs etc. A dehydrogenated PAH molecule might subsequently form fullerenes in the ISM as a result of ongoing chemical processes. This work presents a density functional theory (DFT) calculation on dehydrogenated PAH anions to explore the infrared emission spectra of these molecules and discuss any possible contribution towards observed IR features in the ISM. The results suggest that dehydrogenated PAH anions might be significantly contributing to the 3.3 μm region. Spectroscopic features unique to dehydrogenated PAH anions are highlighted that may be used for their possible identification in the ISM. A comparison has also been made to see the size effect on spectra of these PAHs.

  12. Are PAHS the Right Metric for Assessing Toxicity Related to Oils, Tars, Creosote and Similar Contaminants in Sediments?

    Science.gov (United States)

    Oils, tars, and other non-aqueous phase hydrocarbon liquids (NAPLs) are common sources of contamination in aquatic sediments, and the toxicity of such contamination has generally been attributed to component chemicals, particularly PAHs. While there is no doubt PAHs can be toxic ...

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

    Science.gov (United States)

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

    2015-06-01

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

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

    Science.gov (United States)

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

    2015-01-01

    The formation of more polar and toxic polycyclic aromatic hydrocarbon (PAH) transformation products is one of the concerns associated with the bioremediation of PAH-contaminated soils. Soil contaminated with coal tar (pre-bioremediation) from a former manufactured gas plant (MGP) site was treated in a laboratory scale bioreactor (post-bioremediation) and extracted using pressurized liquid extraction. The soil extracts were fractionated, based on polarity, and analyzed for 88 PAHs (unsubstituted, oxygenated, nitrated, and heterocyclic PAHs). The PAH concentrations in the soil tested, post-bioremediation, were lower than their regulatory maximum allowable concentrations (MACs), with the exception of the higher molecular weight PAHs (BaA, BkF, BbF, BaP, and IcdP), most of which did not undergo significant biodegradation. The soil extract fractions were tested for genotoxicity using the DT40 chicken lymphocyte bioassay and developmental to xicity using the embryonic zebrafish (Danio rerio) bioassay. A statistically significant increase in genotoxicity was measured in the unfractionated soil extract, as well as in four polar soil extract fractions, post-bioremediation (p bioremediation (p bioremediation. The increased toxicity measured post-bioremediation is not likely due to the 88 PAHs measured in this study (including quinones), because most were not present in the toxic polar fractions and/or because their concentrations did not increase post-bioremediation. However, the increased toxicity measured post-bioremediation is likely due to hydroxylated and carboxylated transformation products of the 3- and 4-ring PAHs (PHE, 1MPHE, 2MPHE, PRY, BaA, and FLA) that were most degraded. PMID:26200254

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

    Science.gov (United States)

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

    2015-12-01

    The formation of more polar and toxic polycyclic aromatic hydrocarbon (PAH) transformation products is one of the concerns associated with the bioremediation of PAH-contaminated soils. Soil contaminated with coal tar (prebioremediation) from a former manufactured gas plant (MGP) site was treated in a laboratory scale bioreactor (postbioremediation) and extracted using pressurized liquid extraction. The soil extracts were fractionated, based on polarity, and analyzed for 88 PAHs (unsubstituted, oxygenated, nitrated, and heterocyclic PAHs). The PAH concentrations in the soil tested, postbioremediation, were lower than their regulatory maximum allowable concentrations (MACs), with the exception of the higher molecular weight PAHs (BaA, BkF, BbF, BaP, and IcdP), most of which did not undergo significant biodegradation. The soil extract fractions were tested for genotoxicity using the DT40 chicken lymphocyte bioassay and developmental toxicity using the embryonic zebrafish (Danio rerio) bioassay. A statistically significant increase in genotoxicity was measured in the unfractionated soil extract, as well as in four polar soil extract fractions, postbioremediation (p toxicity was measured in one polar soil extract fraction, postbioremediation (p soil extract fractions in embryonic zebrafish, both pre- and postbioremediation. The increased toxicity measured postbioremediation is not likely due to the 88 PAHs measured in this study (including quinones), because most were not present in the toxic polar fractions and/or because their concentrations did not increase postbioremediation. However, the increased toxicity measured postbioremediation is likely due to hydroxylated and carboxylated transformation products of the 3- and 4-ring PAHs (PHE, 1MPHE, 2MPHE, PRY, BaA, and FLA) that were most degraded.

  16. NOx and PAHs removal from industrial flue gas by using electron beam technology in the alcohol addition

    International Nuclear Information System (INIS)

    Sun, Y.X.; Chmielewski, A.G.; Bulka, S.; Zimek, Z.; Licki, J.; Kubica, K.

    2002-01-01

    Complete text of publication follows. The preliminary test of NO x and Polycyclic Aromatic Hydrocarbons (PAHs) removal from flue gas were investigated in the alcohol addition by using electron beam irradiation in EPS Kaweczyn. Experimental conditions were as follows: flue gas flow rate 5000 nM 3 /hr; humidity 4-5%; inlet concentrations of SO 2 and NO x , which were emitted from power station, were 192 ppm and 106 ppm, respectively; ammonia addition is 2.75 m 3 /hr; alcohol addition is 600 l/hr. It was found that NO x removal efficiency in the presence of alcohol was increased by 10% than without alcohol addition when the absorbed dose was below 6 kGy. The NO x removal efficiency was decreased when the absorbed dose was higher than 10 kGy. In order to understand PAHs' behavior under EB irradiation, inlet PAHs (emitted from coal combustion process) sample and outlet PAHs (after irradiation) sample were collected by using a condensed bottle connected with XAD-2 adsorbent and active carbon adsorbent and were analyzed by a GC-MS. It is found that: at the 8 kGy adsorbed dose, concentrations of PAHs with small aromatic rings (≤3, except Acenaphthylene) are reduced and concentrations of PAHs with large aromatic rings (≤4) are increased. A possible mechanism is proposed

  17. Levels and sources of PAHs in selected sites from Portugal: biomonitoring with Pinus pinea and Pinus pinaster needles.

    Science.gov (United States)

    Ratola, Nuno; Amigo, José Manuel; Alves, Arminda

    2010-04-01

    Pine needle samples from two pine species (Pinus pinaster Ait. and Pinus pinea L.) were collected at 29 sites scattered throughout Portugal, in order to biomonitor the levels and trends of 16 polycyclic aromatic hydrocarbons (PAHs). The values obtained for the sum of all PAHs ranged from 76 to 1944 ng/g [dry weight (dw)]. Despite the apparent matrix similarities between both pine species, P. pinaster needles revealed higher mean entrapment levels than P. pinea (748 and 399 ng/g (dw) per site, respectively). The urban and industrial sites have the highest average of PAH incidence [for P. pinea, 465 and 433 ng/g (dw) per site, respectively, and for P. pinaster, 1147 and 915 ng/g (dw)], followed by the rural sites [233 ng/g and 711 ng/g (dw) per site, for P. pinea and P. pinaster, respectively]. The remote sites, both from P. pinaster needles, show the least contamination, with 77 ng/g (dw) per site. A predominance of 3-ring and 4-ring PAHs was observed in most samples, with phenanthrene having 30.1% of the total. Naphthalene prevailed in remote sites. Rainfall had no influence on the PAHs levels, but there was a relationship between higher wind speeds and lower concentrations. PAH molecular ratios revealed the influence of both petrogenic and pyrogenic sources.

  18. In situ treatment of soil contaminated with PAHs and phenols

    International Nuclear Information System (INIS)

    Sresty, G.; Dev, H.; Chang, J.; Houthoofd, J.

    1992-01-01

    The wood preserving industry uses more pesticides than any other industry worldwide. The major chemicals used are creosote, pentachlorophenol, and CCA (copper, chrome and arsenate). It is reported that between 415 to 550 creosoting operations within the United States consume approximately 454,000 metric tons of creosote annually. When properly used and disposed off, creosote does not appear to significantly threaten human health. However, due to improper disposal and spillage at old facilities, creosote and other wood preserving chemicals have found their way into surface soils. Active wood preserving sites generate an estimated 840 to 1530 dry metric tons of hazardous contaminated sludge annually, which is classified as KOOL. Creosote, obtained from coal tar, contains a large number of chemical components. The three main families of compounds represented in creosote are: polycyclic aromatic hydrocarbons (PAH), phenolic, and heterocyclic compounds. Creosote is composed of approximately 85% PAHs, 10% phenolic compounds and 5% heterocyclic compounds. There are approximately a total of 17 PAHs present in creosote. The four most prominent compounds belonging to the PAH family are naphthalene, 2-methylnaphthalene, phenanthrene, and anthracene. These four compounds represent approximately 52% of the total PAHs present in creosote. There are approximately 12 different phenolic compounds present in creosote among which phenol is the most abundant, representing 20% of the total phenolics. In addition, the various isomers of cresol represent about 20% and pentachlorophenol (PCP) represents 10% of the total phenolics. There are approximately 13 different heterocyclic compounds are the most abundant, representing approximately 70% of the total heterocyclics. All of these compounds possess toxic properties and some of them, for example, PCP, when subjected to high temperature environments are suspected precursors in the formation of dioxins

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

    Science.gov (United States)

    Lu, Yan-Fei; Lu, Mang

    2015-03-21

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

  20. Could the Health Decline of Prehistoric California Indians be Related to Exposure to Polycyclic Aromatic Hydrocarbons (PAHs) from Natural Bitumen?

    Science.gov (United States)

    Sholts, Sabrina B.; Erlandson, Jon M.; Gjerdrum, Thor; Westerholm, Roger

    2011-01-01

    Background: The negative health effects of polycyclic aromatic hydrocarbons (PAHs) are well established for modern human populations but have so far not been studied in prehistoric contexts. PAHs are the main component of fossil bitumen, a naturally occurring material used by past societies such as the Chumash Indians in California as an adhesive, as a waterproofing agent, and for medicinal purposes. The rich archaeological and ethnohistoric record of the coastal Chumash suggests that they were exposed to multiple uptake pathways of bituminous PAHs, including direct contact, fume inhalation, and oral uptake from contaminated water and seafood. Objectives: We investigated the possibility that PAHs from natural bitumen compromised the health of the prehistoric Chumash Indians in California. Conclusions: Exposure of the ancient Chumash Indians to toxic PAHs appears to have gradually increased across a period of 7,500 years because of an increased use of bitumen in the Chumash technology, together with a dietary shift toward PAH-contaminated marine food. Skeletal analysis indicates a concurrent population health decline that may be related to PAH uptake. However, establishing such a connection is virtually impossible without knowing the actual exposure levels experienced by these populations. Future methodological research may provide techniques for determining PAH levels in ancient skeletal material, which would open new avenues for research on the health of prehistoric populations and on the long-term effects of human PAH exposure. PMID:21596651

  1. The Diversity of PAH-degrading bacteria in a deep-sea water column above the Southwest Indian Ridge

    Directory of Open Access Journals (Sweden)

    Zongze eShao

    2015-08-01

    Full Text Available The bacteria involved in organic pollutant degradation in pelagic deep-sea environments are largely unknown. In this report, the diversity of polycyclic aromatic hydrocarbon ( PAH-degrading bacteria was analyzed in deep-sea water on the Southwest Indian Ridge (SWIR. After enrichment with a PAH mixture (phenanthrene, anthracene, fluoranthene and pyrene, 9 nine bacterial consortia were obtained from depths of 3946 m to 4746 m. PAH degradation occurred to all components of the mixture, but when using a single PAH as the sole carbon and energy source, only phenanthrene can be degraded obviously. This indicates the cometabolism of anthracene, fluoranthene and pyrene with phenanthreneWhile the consortia degraded all four PAHs when supplied in a mixture, when PAHs were tested individually, only phenanthrene supported growth. Thus, degradation of the PAH mixture reflected a cometabolism of anthracene, fluoranthene and pyrene with phenanthrene. Further, both culture-dependent and independent methods revealed many new bacteria involved in PAH degradation. Specifically, the alpha and gamma subclasses of Proteobacteria were confirmed as the major groups within the communities. Additionally, Actinobacteria, the CFB group and Firmicutes were detected. Denaturing Gradient Gel Electrophoresis (DGGE analysis showed that bacteria closely affiliated with Alcanivorax, Novosphingobium and Rhodovulum occurred most frequently in different PAH-degrading consortia. More than half of the isolates (34 of 51 isolates were confirmed to have the ability to grow with the PAH mixture By using general heterotrophic media, 51 bacteria were isolated from the consortia and of these 34 grew with the PAH mixture as a sole carbon source. Of these, isolates most closely related to Alterierythrobacter, Citricella, Erythrobacter, Idiomarina, Lutibacterium, Maricaulis, Marinobacter, Martelella, Pseudidiomarina, Rhodobacter, Roseovarius, Salipiger, Sphingopyxis and Stappia were found to

  2. RINGED ACCRETION DISKS: EQUILIBRIUM CONFIGURATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Pugliese, D.; Stuchlík, Z., E-mail: d.pugliese.physics@gmail.com, E-mail: zdenek.stuchlik@physics.cz [Institute of Physics and Research Centre of Theoretical Physics and Astrophysics, Faculty of Philosophy and Science, Silesian University in Opava, Bezručovo náměstí 13, CZ-74601 Opava (Czech Republic)

    2015-12-15

    We investigate a model of a ringed accretion disk, made up by several rings rotating around a supermassive Kerr black hole attractor. Each toroid of the ringed disk is governed by the general relativity hydrodynamic Boyer condition of equilibrium configurations of rotating perfect fluids. Properties of the tori can then be determined by an appropriately defined effective potential reflecting the background Kerr geometry and the centrifugal effects. The ringed disks could be created in various regimes during the evolution of matter configurations around supermassive black holes. Therefore, both corotating and counterrotating rings have to be considered as being a constituent of the ringed disk. We provide constraints on the model parameters for the existence and stability of various ringed configurations and discuss occurrence of accretion onto the Kerr black hole and possible launching of jets from the ringed disk. We demonstrate that various ringed disks can be characterized by a maximum number of rings. We present also a perturbation analysis based on evolution of the oscillating components of the ringed disk. The dynamics of the unstable phases of the ringed disk evolution seems to be promising in relation to high-energy phenomena demonstrated in active galactic nuclei.

  3. Occupational PAH Exposures during Prescribed Pile Burns

    Science.gov (United States)

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

    2008-01-01

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

  4. PAHS

    African Journals Online (AJOL)

    user

    2011-03-02

    Mar 2, 2011 ... spillage's and/or heavy ship traffic. However, the ... various aspects such as industrial effluents, air, highway vehicle exhaust and highway .... detection (LOD) of the GC-MS method, established at signals three times that of the.

  5. Source and Ecological Risk Characteristics of PAHs in Sediments from Qinhuai River and Xuanwu Lake, Nanjing, China

    Directory of Open Access Journals (Sweden)

    Zhenhua Zhao

    2017-01-01

    Full Text Available In order to investigate the residual characteristics, sources, and ecological risk of PAHs in sediment from urban rivers, the sediments of 15 typical sites from Qinhuai River and Xuanwu Lake, which are typical urban rivers and lake, were collected from October 2015 to July 2016; the sources of PAHs in sediment were also identified by several methods. Results showed that ∑PAHs concentration in sediment ranged from 796.2 ng/g to 10,470 ng/g with an average of 2,713.8 ng/g. High molecular weight PAHs with 4-5 rings were most prominent in the sediment during all four seasons. Source characterization studies based on the analysis of diagnostic ratio (triangular plot method, cluster analysis, and positive factor matrix analysis suggested that the PAHs of Qinhuai River Basin were mainly from pyrogenic origin (biomass and coal combustion and vehicular emission, and the petroleum source also cannot be ignored (specially in summer. Most individual PAHs occasionally affect the aquatic organisms. The highest benzo[a]pyrene-equivalent doses (BaPeq dose appear at the sites of sewage discharge and heavy traffic. So, the PAHs pollution sources of urban water body have obvious seasonal-dependent and human activities-dependent characteristics.

  6. Lichens biomonitoring as feasible methodology to assess air pollution in natural ecosystems: combined study of quantitative PAHs analyses and lichen biodiversity in the Pyrenees Mountains.

    Science.gov (United States)

    Blasco, María; Domeño, Celia; Nerín, Cristina

    2008-06-01

    The air quality in the Aragón valley, in the central Pyrenees, has been assessed by evaluation of lichen biodiversity and mapped by elaboration of the Index of Air Purity (IAP) based on observations of the presence and abundance of eight kinds of lichen with different sensitivity to air pollution. The IAP values obtained have been compared with quantitative analytical measures of 16 PAHs in the lichen Evernia prunastri, because this species was associated with a wide range of traffic exposure and levels of urbanization. Analyses of PAHs were carried out by the DSASE method followed by an SPE clean-up step and GC-MS analysis. The concentration of total PAHs found in lichen samples from the Aragón valley ranged from 692 to 6420 ng g(-1) and the PAHs profile showed predominance of compounds with three aromatic rings. The influence of the road traffic in the area has been shown because values over the median concentration of PAHs (>1092 ng g(-1)), percentage of combustion PAHs (>50%), and equivalent toxicity (>169) were found in lichens collected at places exposed to the influence of traffic. The combination of both methods suggests IAP as a general method for evaluating the air pollution referenced to PAHs because it can be correlated with the content of combustion PAHs and poor lichen biodiversity can be partly explained by the air pollution caused by specific PAHs.

  7. Source characterisation and distribution of selected PCBs, PAHs and alkyl PAHs in sediments from the Klip and Jukskei Rivers, South Africa.

    Science.gov (United States)

    Rimayi, Cornelius; Chimuka, Luke; Odusanya, David; de Boer, Jacob; Weiss, Jana M

    2017-07-01

    A study of the distribution of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) utilising 16 priority PAHs, benzo(e)pyrene, perylene, 19 alkylated PAHs and 31 ortho substituted PCBs in South Africa is presented. It was aimed to (a) deduce characteristic contamination patterns for both PCBs and PAHs and (b) provide the first comprehensive dataset for establishment of source characterisation of PCBs and PAHs. This is in line with new South African legislation on mandatory monitoring of PCB and PAH emissions. Bar charts, principal component analysis (PCA) and biplots were utilised to identify signature contamination patterns and distribution of PCBs and PAHs within the Jukskei and Klip Rivers. Sediments from the Jukskei and Klip River catchments both showed distinct contamination signatures for hexa to nonachlorinated PCBs, characteristic of contamination by Aroclor 1254 and 1260 technical mixtures. PCB signature patterns in order of abundance were 138 > 180 > 206 > 153 > 187 > 149 and 138 > 153 > 180 > 149 > 187 > 110 > 170 for the Jukskei and Klip River sediments, respectively. The upstream Alberton point had the highest Σ31 PCB and Σ (parent+alkyl) PAH concentrations in the Klip River of 61 and 6000 μg kg -1 dry weight (dw), respectively. In the Jukskei River, the upstream Marlboro point had the highest Σ31 PCB concentration of 19 μg kg -1 dw and the N14 site recorded the highest Σ (parent+alkyl) PAH concentration of 2750 μg kg -1 dw. PAH concentrations in both the Jukskei and Klip Rivers were significantly higher than the PCB concentrations. Fluoranthene, phenanthrene and pyrene were found in the highest concentrations in both the Jukskei and Klip River sediments. Both the Jukskei and Klip River sediments showed trends of a mixed pyrogenic-petrogenic PAH source contamination.

  8. Interactions between selected PAHs and the microbial community in rhizosphere of a paddy soil.

    Science.gov (United States)

    Su, Yu H; Yang, Xue Y

    2009-01-15

    This study investigated the interaction of three polycyclic aromatic hydrocarbons (PAHs), i.e., naphthalene (NAP), phenanthrene (PHN), and pyrene (PYR), with the microbial community in the rhizosphere of a paddy soil and the influence of the rice (Oryza sativa) rhizosphere on the microbial community structure. A range of initial NAP, PHN and PYR levels in soil (50-200, 18-72, and 6.6-26.6 mg kg(-1), respectively) were prepared and the soil samples were then aged for 4 months (to yield PAH concentrations at 1.02-1.42, 1.32-4.77, and 2.98-18.5 mg kg(-)(1), respectively) before the soil samples were planted with rice seedlings. The microbial phospholipid-fatty-acid (PLFA) patterns in PAH-contaminated soils were analyzed to elucidate the changes of the microbial biomass and community composition. Results indicated that at the applied concentrations the PAHs were not toxic to rice seedlings, as evidenced by no growth inhibition during the 8-week planting period. However, the microbial biomass, as revealed by PLFAs, decreased significantly with increasing PAH concentration in both rhizospheric and non-rhizospheric soils. The PAHs in soils were obviously toxic to microorganisms, and the toxicity of PHN was greater than PYR due likely to the higher PHN bioavailability. Total PLFAs in rhizospheric soils were profoundly higher than those in non-rhizospheric soils, suggesting that the inhibitive effect of PAHs on microbial activities was alleviated by the rice roots. The principal component analysis (PCA) of the PLFA signatures revealed pronounced changes in PLFA pattern in rhizospheric and non-rhizospheric soils with or without spiked PAHs. Using the PLFA patterns as a biomarker, it was found that Gram-positive bacteria were more sensitive to PAHs than Gram-negative bacteria, and the rhizosphere of rice roots stimulated the growth of aerobic bacteria.

  9. Influence of PAHs among other coastal environmental variables on total and PAH-degrading bacterial communities.

    Science.gov (United States)

    Sauret, Caroline; Tedetti, Marc; Guigue, Catherine; Dumas, Chloé; Lami, Raphaël; Pujo-Pay, Mireille; Conan, Pascal; Goutx, Madeleine; Ghiglione, Jean-François

    2016-03-01

    We evaluated the relative impact of anthropogenic polycyclic aromatic hydrocarbons (PAHs) among biogeochemical variables on total, metabolically active, and PAH bacterial communities in summer and winter in surface microlayer (SML) and subsurface seawaters (SSW) across short transects along the NW Mediterranean coast from three harbors, one wastewater effluent, and one nearshore observatory reference site. At both seasons, significant correlations were found between dissolved total PAH concentrations and PAH-degrading bacteria that formed a gradient from the shore to nearshore waters. Accumulation of PAH degraders was particularly high in the SML, where PAHs accumulated. Harbors and wastewater outfalls influenced drastically and in a different way the total and active bacterial community structure, but they only impacted the communities from the nearshore zone (PAH concentrations on the spatial and temporal dynamic of total and active communities in this area, but this effect was putted in perspective by the importance of other biogeochemical variables.

  10. Water quality concerns due to forest fires: polycyclic aromatic hydrocarbons (PAH) contamination of groundwater from mountain areas.

    Science.gov (United States)

    Mansilha, C; Carvalho, A; Guimarães, P; Espinha Marques, J

    2014-01-01

    Water quality alterations due to forest fires may considerably affect aquatic organisms and water resources. These impacts are cumulative as a result of pollutants mobilized from fires, chemicals used to fight fire, and postfire responses. Few studies have examined postfire transport into water resources of trace elements, including the polycyclic aromatic hydrocarbons (PAH), which are organic pollutants produced during combustion and are considered carcinogenic and harmful to humans. PAH are also known to adversely affect survival, growth, and reproduction of many aquatic species. This study assessed the effects of forest wildfires on groundwater from two mountain regions located in protected areas from north and central Portugal. Two campaigns to collect water samples were performed in order to measure PAH levels. Fifteen of 16 studied PAH were found in groundwater samples collected at burned areas, most of them at concentrations significantly higher than those found in control regions, indicating aquifer contamination. The total sum of PAH in burned areas ranged from 23.1to 95.1 ng/L with a median of 62.9 ng/L, which is one- to sixfold higher than the average level measured in controls (16.2 ng/L). In addition, in control samples, the levels of light PAH with two to four rings were at higher levels than heavy PAH with five or six rings, thus showing a different profile between control and burned sites. The contribution of wildfires to groundwater contamination by PAH was demonstrated, enabling a reliable assessment of the impacts on water quality and preparation of scientifically based decision criteria for postfire forest management practices.

  11. The differences in transformation mechanism in natural and anthropogenic PAH in environmental system

    International Nuclear Information System (INIS)

    Navai, A.I.; Abasova, D.R.; Suleymanov, B.A.

    2005-01-01

    Full text : In present time, with the large reliability the established fact, that the majority of polycyclic aromatic hydrocarbons acting in an environment as from natural (fires, volcanic activity etc.) and from anthropogenesis (emissions of the industrial enterprises, the exhaust gases of automobiles etc.) sources, have carcinogenic activity. Toxicity and persistence of PAH and also their significant prevalence and their ability to be accumulated in an environment, cause necessity of the constant control most harmful polycyclic aromatic hydrocarbons in a various wide spectrum of natural matrixes - air, water, ground adjournment, ground, vegetative and animal fabrics and secretion, products of a meal. From natural sources creating a background level by PAH, is possible to note their synthesis from some plants and microorganisms, wood fires, volcanic activity and meteoric dust and etc. Anthropogenesis PAH pollution an environmental, the problem carries global character. PAH are formed as collateral products at processes of high-temperature processing of organic raw material, mainly, on oil refining, by-product-coking industry, aluminium manufactures. One of the basic sources of pollution PAH of an environment is the vehicle exhaust gases of automobiles are revealed more than 150 PAH. A significant role in PAH formation play aircraft and navigation. It is impossible to exclude an opportunity of pollution of an environment by components PAH, around and along transport pipelines. The reason to this can be oils outflow during transportation or clearing of pipelines. In the publications there is information on presence PAH in Absheron oils. But this information is not sufficient for PAI components specification. We carried out polycyclic aromatic hydrocarbons research's in oils structure of Absheron peninsula. At the first were investigated the average oils samples, which have taken from Surakhani oilfield. In Surakhani oils were found the following PAH components (in

  12. Microplastics and polycyclic aromatic hydrocarbons (PAHs) in Xiamen coastal areas: Implications for anthropogenic impacts.

    Science.gov (United States)

    Tang, Guowen; Liu, Mengyang; Zhou, Qian; He, Haixia; Chen, Kai; Zhang, Haibo; Hu, Jiahui; Huang, Qinghui; Luo, Yongming; Ke, Hongwei; Chen, Bin; Xu, Xiangrong; Cai, Minggang

    2018-09-01

    Microplastics and polycyclic aromatic hydrocarbons (PAHs) were investigated to study the influence of human activities and to find their possible relationship on the coastal environments, where the coastal areas around Xiamen are undergoing intensive processes of industrialization and urbanization in the southeast China. The abundance of microplastics in Xiamen coastal areas was 103 to 2017particles/m 3 in surface seawater and 76 to 333 particles/kg in sediments. Concentrations of dissolved PAHs varied from 18.1 to 248ng/L in surface seawater. The abundances of microplastics from the Western Harbor in surface seawater and sediments were higher than those from other areas. Foams were dominated in surface seawater samples, however, no foams were found in sediments samples. The microscope selection and FTIR analysis suggested that polyethylene (PE) and polypropylene (PP) were dominant microplastics. The cluster analysis results demonstrated that fibers and granules had the similar sources, and films had considerably correlation with all types of PAHs (3 or 4-ring PAHs and alkylated PAHs). Plastic film mulch from agriculture practice might be a potential source of microplastics in study areas. Results of our study support that river runoff, watershed area, population and urbanization rate influence the distribution of microplastics in estuarine surface water, and the prevalence of microplastic pollution calls for monitoring microplastics at a national scale. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. Comparative metagenomic analysis of PAH degradation in soil by a mixed microbial consortium.

    Science.gov (United States)

    Zafra, German; Taylor, Todd D; Absalón, Angel E; Cortés-Espinosa, Diana V

    2016-11-15

    In this study, we used a taxonomic and functional metagenomic approach to analyze some of the effects (e.g. displacement, permanence, disappearance) produced between native microbiota and a previously constructed Polycyclic Aromatic Hydrocarbon (PAH)-degrading microbial consortium during the bioremediation process of a soil polluted with PAHs. Bioaugmentation with a fungal-bacterial consortium and biostimulation of native microbiota using corn stover as texturizer produced appreciable changes in the microbial diversity of polluted soils, shifting native microbial communities in favor of degrading specific populations. Functional metagenomics showed changes in gene abundance suggesting a bias towards aromatic hydrocarbon and intermediary degradation pathways, which greatly favored PAH mineralization. In contrast, pathways favoring the formation of toxic intermediates such as cytochrome P450-mediated reactions were found to be significantly reduced in bioaugmented soils. PAH biodegradation in soil using the microbial consortium was faster and reached higher degradation values (84% after 30 d) as a result of an increased co-metabolic degradation when compared with other mixed microbial consortia. The main differences between inoculated and non-inoculated soils were observed in aromatic ring-hydroxylating dioxygenases, laccase, protocatechuate, salicylate and benzoate-degrading enzyme genes. Based on our results, we propose that several concurrent metabolic pathways are taking place in soils during PAH degradation. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Treatment of PAHs in waters using the GAC-FBR process

    International Nuclear Information System (INIS)

    Hickey, R.F.; Sunday, A.; Wagner, D.; Groshko, V.; Rajan, R.V.; Leuschner, A.; Hayes, T.D.

    1995-01-01

    Pilot studies were conducted to determine the utility of the granular activated carbon fluidized-bed reactor (GAC-FBR) process to treat groundwater from manufactured gas plant (MGP) sites containing polycyclic aromatic hydrocarbons (PAHs) and a process effluent water from a deep subsurface dense, nonaqueous-phase liquid (DNAPL) removal process at an MGP site. Removal of naphthalene exceeded 99.9%, and overall PAH removals of 99+% were observed at organic loading rates (OLRs) exceeding 4-kg chemical oxygen demand (COD)/m 3 -d and a hydraulic retention time (HRT) of about 6 min. Analysis of PAHs accumulated on GAC and oxygen consumption clearly demonstrated that removal of 2- to 4-ring PAHs was due primarily to biological oxidation and not to adsorption. Analysis of influent and effluent samples using Microtox reg-sign indicated removal of toxicity. Full-scale application of the GAC-FBR process has begun at a Superfund site in Pennsylvania. The GAC-FBR is being used to treat a 15-gal per min (gpm) process effluent flow from a subsurface DNAPL removal process. Initial results confirm the ability of the process to treat PAHs at high OLRs and short HRTs

  15. Environmental assessment of polycyclic aromatic hydrocarbons (PAHs) in surface sediments of the Santander Bay, Northern Spain.

    Science.gov (United States)

    Viguri, J; Verde, J; Irabien, A

    2002-07-01

    Samples of intertidal surface sediments (0-2 cm) were collected in 17 stations of the Santander Bay, Cantabric Sea, Northern Spain. The concentrations of polycyclic aromatic hydrocarbons (PAHs), 16, were analysed by HPLC and MS detection. Surface sediments show a good linear correlation among the parameters of the experimental organic matter evaluation, where total carbon (TC) and loss on ignition (LOI) are approximately 2.5 and 5 times total organic carbon (TOC). A wide range of TOC from 0.08% to 4.1%, and a broad distribution of the sum of sigma16PAHs, from 0.02 to 344.6 microg/g d.w., which can be correlated by an exponential equation to the TOC, has been identified. A qualitative relationship may be established between the industrial input along the rivers and the concentration of sigma6PAHs in the sediments of the estuaries: Boo estuary (8404-4631 microg/g OC), Solia-San Salvador estuaries (305-113 microg/g OC) and Cubas estuary (31-32 microg/g OC). This work shows a dramatic change in the spatial distribution in the concentration of PAHs of intertidal surface sediments. The left edge of the Bay has the main traffic around the city and the major source of PAHs is from combustion processes and estuarine inputs, leading to medium values of PAHs in the sediments; the right edge of the Bay has much lesser anthropogenic activities leading to lower values of PAHs in sediments. The distribution of individual PAHs in sediments varies widely depending on their structure and molecular weight; the 4-6 ring aromatics predominate in polluted sediments due to their higher persistence. The isomer ratio does not allow any clear identification of the PAHs origin. Environmental evaluation according to Dutch guidelines and consensus sediment quality guidelines based on ecotoxicological data leads to the same conclusion, sediments in the Santander Bay show a very different environmental quality depending on the spatial position from heavily polluted/medium effects to non

  16. Placental IGF-1 and IGFBP-3 expression correlate with umbilical cord blood PAH and PBDE levels from prenatal exposure to electronic waste

    International Nuclear Information System (INIS)

    Xu, Xijin; Yekeen, Taofeek Akangbe; Xiao, Qiongna; Wang, Yuangping; Lu, Fangfang; Huo, Xia

    2013-01-01

    Electronic waste recycling produces Polycyclic Aromatic Hydrocarbons (PAHs) and Polybrominated Diphenyl Ethers (PBDEs) which may affect fetal growth and development by altering the insulin-like-growth factor (IGF) system. Questionnaires were administered to pregnant women (Guiyu, an e-waste site, n = 101; control, n = 53), and umbilical cord blood (UCB) and placentas were collected upon delivery. PBDEs and PAHs in UCB and placental IGF-1 and IGFBP-3 mRNA levels were analyzed using GC–MS and real-time PCR, respectively. Infant birth length and Apgar scores were lower in Guiyu. All PAHs (except Fl, Chr, IP, BbF and BP), total 16-PAHs, total/individual PBDEs, placental IGF-1 (median 0.23 vs 0.19; P < 0.05) and IGFBP-3 (median 1.91 vs 0.68; P < 0.001) levels were significantly higher in Guiyu. Spearman correlation showed that BDE-154, BDE-209 and ∑5ring-PAHs positively correlate with IGF-1 while PBDEs, 4 rings and total PAHs correlate with IGFBP-3 expression. Increased placental IGF-1 level might indirectly affect fetal growth and development. -- Highlights: •PAHs and PBDEs from e-waste may affect fetal growth via alteration of IGF system. •Infant birth length and Apgar scores were lower in Guiyu compared to Chaoan. •Most PAHs, all PBDEs, IGF-1 and IGFBP-3 levels were significantly higher in Guiyu. •IGF-1 positively correlates with BDE-154, BDE-209 and ∑5ring-PAHs. •The observed increase in IGF-1 might indirectly affect fetal growth and development. -- The correlation between POPs and placental IGF-1 and IGFBP-3 assessed provides more information on the human health risk associated with electronic waste

  17. Response of bacterial pdo1, nah, and C12O genes to aged soil PAH pollution in a coke factory area.

    Science.gov (United States)

    Han, Xue-Mei; Liu, Yu-Rong; Zheng, Yuan-Ming; Zhang, Xiao-Xia; He, Ji-Zheng

    2014-01-01

    Soil pollution caused by polycyclic aromatic hydrocarbons (PAHs) is threatening human health and environmental safety. Investigating the relative prevalence of different PAH-degrading genes in PAH-polluted soils and searching for potential bioindicators reflecting the impact of PAH pollution on microbial communities are useful for microbial monitoring, risk evaluation, and potential bioremediation of soils polluted by PAHs. In this study, three functional genes, pdo1, nah, and C12O, which might be involved in the degradation of PAHs from a coke factory, were investigated by real-time quantitative PCR (qPCR) and clone library approaches. The results showed that the pdo1 and C12O genes were more abundant than the nah gene in the soils. There was a significantly positive relationship between the nah or pdo1 gene abundances and PAH content, while there was no correlation between C12O gene abundance and PAH content. Analyses of clone libraries showed that all the pdo1 sequences were grouped into Mycobacterium, while all the nah sequences were classified into three groups: Pseudomonas, Comamonas, and Polaromonas. These results indicated that the abundances of nah and pdo1 genes were positively influenced by levels of PAHs in soil and could be potential microbial indicators reflecting the impact of soil PAH pollution and that Mycobacteria were one of the most prevalent PAHs degraders in these PAH-polluted soils. Principal component analysis (PCA) and correlation analyses between microbial parameters and environmental factors revealed that total carbon (TC), total nitrogen (TN), and dissolved organic carbon (DOC) had positive effects on the abundances of all PAH-degrading genes. It suggests that increasing TC, TN, and DOC inputs could be a useful way to remediate PAH-polluted soils.

  18. ring system

    African Journals Online (AJOL)

    1,3,2-DIAZABORACYCLOALKANE. RING SYSTEM. Negussie Retta" and Robert H. Neilson. 'Department of Chemistry, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia. Department of Chemistry, Texas Christian University.

  19. Planetary Rings

    Science.gov (United States)

    Nicholson, P. D.

    2001-11-01

    A revolution in the studies in planetary rings studies occurred in the period 1977--1981, with the serendipitous discovery of the narrow, dark rings of Uranus, the first Voyager images of the tenuous jovian ring system, and the many spectacular images returned during the twin Voyager flybys of Saturn. In subsequent years, ground-based stellar occultations, HST observations, and the Voyager flybys of Uranus (1986) and Neptune (1989), as well as a handful of Galileo images, provided much additional information. Along with the completely unsuspected wealth of detail these observations revealed came an unwelcome problem: are the rings ancient or are we privileged to live at a special time in history? The answer to this still-vexing question may lie in the complex gravitational interactions recent studies have revealed between the rings and their retinues of attendant satellites. Among the four known ring systems, we see elegant examples of Lindblad and corotation resonances (first invoked in the context of galactic disks), electromagnetic resonances, spiral density waves and bending waves, narrow ringlets which exhibit internal modes due to collective instabilities, sharp-edged gaps maintained via tidal torques from embedded moonlets, and tenuous dust belts created by meteoroid impact onto parent bodies. Perhaps most puzzling is Saturn's multi-stranded, clumpy F ring, which continues to defy a simple explanation 20 years after it was first glimpsed in grainy images taken by Pioneer 11. Voyager and HST images reveal a complex, probably chaotic, dynamical interaction between unseen parent bodies within this ring and its two shepherd satellites, Pandora and Prometheus. The work described here reflects contributions by Joe Burns, Jeff Cuzzi, Luke Dones, Dick French, Peter Goldreich, Colleen McGhee, Carolyn Porco, Mark Showalter, and Bruno Sicardy, as well as those of the author. This research has been supported by NASA's Planetary Geology and Geophysics program and the

  20. Using deuterated PAH amendments to validate chemical extraction methods to predict PAH bioavailability in soils

    International Nuclear Information System (INIS)

    Gomez-Eyles, Jose L.; Collins, Chris D.; Hodson, Mark E.

    2011-01-01

    Validating chemical methods to predict bioavailable fractions of polycyclic aromatic hydrocarbons (PAHs) by comparison with accumulation bioassays is problematic. Concentrations accumulated in soil organisms not only depend on the bioavailable fraction but also on contaminant properties. A historically contaminated soil was freshly spiked with deuterated PAHs (dPAHs). dPAHs have a similar fate to their respective undeuterated analogues, so chemical methods that give good indications of bioavailability should extract the fresh more readily available dPAHs and historic more recalcitrant PAHs in similar proportions to those in which they are accumulated in the tissues of test organisms. Cyclodextrin and butanol extractions predicted the bioavailable fraction for earthworms (Eisenia fetida) and plants (Lolium multiflorum) better than the exhaustive extraction. The PAHs accumulated by earthworms had a larger dPAH:PAH ratio than that predicted by chemical methods. The isotope ratio method described here provides an effective way of evaluating other chemical methods to predict bioavailability. - Research highlights: → Isotope ratios can be used to evaluate chemical methods to predict bioavailability. → Chemical methods predicted bioavailability better than exhaustive extractions. → Bioavailability to earthworms was still far from that predicted by chemical methods. - A novel method using isotope ratios to assess the ability of chemical methods to predict PAH bioavailability to soil biota.

  1. Using deuterated PAH amendments to validate chemical extraction methods to predict PAH bioavailability in soils

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Eyles, Jose L., E-mail: j.l.gomezeyles@reading.ac.uk [University of Reading, School of Human and Environmental Sciences, Soil Research Centre, Reading, RG6 6DW Berkshire (United Kingdom); Collins, Chris D.; Hodson, Mark E. [University of Reading, School of Human and Environmental Sciences, Soil Research Centre, Reading, RG6 6DW Berkshire (United Kingdom)

    2011-04-15

    Validating chemical methods to predict bioavailable fractions of polycyclic aromatic hydrocarbons (PAHs) by comparison with accumulation bioassays is problematic. Concentrations accumulated in soil organisms not only depend on the bioavailable fraction but also on contaminant properties. A historically contaminated soil was freshly spiked with deuterated PAHs (dPAHs). dPAHs have a similar fate to their respective undeuterated analogues, so chemical methods that give good indications of bioavailability should extract the fresh more readily available dPAHs and historic more recalcitrant PAHs in similar proportions to those in which they are accumulated in the tissues of test organisms. Cyclodextrin and butanol extractions predicted the bioavailable fraction for earthworms (Eisenia fetida) and plants (Lolium multiflorum) better than the exhaustive extraction. The PAHs accumulated by earthworms had a larger dPAH:PAH ratio than that predicted by chemical methods. The isotope ratio method described here provides an effective way of evaluating other chemical methods to predict bioavailability. - Research highlights: > Isotope ratios can be used to evaluate chemical methods to predict bioavailability. > Chemical methods predicted bioavailability better than exhaustive extractions. > Bioavailability to earthworms was still far from that predicted by chemical methods. - A novel method using isotope ratios to assess the ability of chemical methods to predict PAH bioavailability to soil biota.

  2. Chemical and bioanalytical characterisation of PAHs in risk assessment of remediated PAH-contaminated soils.

    Science.gov (United States)

    Larsson, Maria; Hagberg, Jessika; Rotander, Anna; van Bavel, Bert; Engwall, Magnus

    2013-12-01

    Polycyclic aromatic hydrocarbons (PAHs) are common contaminants in soil at former industrial areas; and in Sweden, some of the most contaminated sites are being remediated. Generic guideline values for soil use after so-called successful remediation actions of PAH-contaminated soil are based on the 16 EPA priority pollutants, which only constitute a small part of the complex cocktail of toxicants in many contaminated soils. The aim of the study was to elucidate if the actual toxicological risks of soil samples from successful remediation projects could be reflected by chemical determination of these PAHs. We compared chemical analysis (GC-MS) and bioassay analysis (H4IIE-luc) of a number of remediated PAH-contaminated soils. The H4IIE-luc bioassay is an aryl hydrocarbon (Ah) receptor-based assay that detects compounds that activate the Ah receptor, one important mechanism for PAH toxicity. Comparison of the results showed that the bioassay-determined toxicity in the remediated soil samples could only be explained to a minor extent by the concentrations of the 16 priority PAHs. The current risk assessment method for PAH-contaminated soil in use in Sweden along with other countries, based on chemical analysis of selected PAHs, is missing toxicologically relevant PAHs and other similar substances. It is therefore reasonable to include bioassays in risk assessment and in the classification of remediated PAH-contaminated soils. This could minimise environmental and human health risks and enable greater safety in subsequent reuse of remediated soils.

  3. Correlations between physicochemical properties of PAHs and their distribution in soil, moss and reindeer dung at Ny-Alesund of the Arctic

    Energy Technology Data Exchange (ETDEWEB)

    Wang Zhen; Ma Xindong; Na Guangshui; Lin Zhongsheng [National Marine Environmental Monitoring Center, Dalian 116023 (China); Ding Qian [Environmental Science and Engineering College, Dalian Maritime University, Dalian 116026 (China); Yao Ziwei, E-mail: zwyao@nmemc.gov.c [National Marine Environmental Monitoring Center, Dalian 116023 (China)

    2009-11-15

    Concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) in soil, moss and reindeer dung collected at Ny-Alesund of the Arctic were measured to investigate their accumulation trends and distribution in the three compartments. Compared with the other regions, the proportions of 2 + 3 ring PAHs to the total PAHs were higher, whereas the proportions of 5 + 6 ring PAHs were lower in the three compartments at Ny-Alesund. Significant log/log-linear relationship was observed between the sub-cooled liquid vapor pressure (p{sub L}{sup o}) and the soil/moss quotient (Q{sub SM}). The relation was similar to the relationship between the gas/particle partition coefficient (K{sub P}) and p{sub L}{sup o} of PAHs, implying Q{sub SM} would be a 'mirror image' of K{sub P}. Excellent log/log-linear relationships were observed between Q{sub SM} and K{sub OA} as well as between the moss/dung quotient (Q{sub MD}) and K{sub OW}. The results presented here indicate the physicochemical properties are suitable for characterizing the distribution of PAHs in soil, moss and reindeer dung. - The physicochemical properties of PAHs are suitable for characterizing their distribution in soil, moss and reindeer dung.

  4. Which hydrogen atom of toluene protonates PAH molecules in (+)-mode APPI MS analysis?

    Science.gov (United States)

    Ahmed, Arif; Ghosh, Manik Kumer; Choi, Myung Chul; Choi, Cheol Ho; Kim, Sunghwan

    2013-03-01

    A previous study (Ahmed, A. et al., Anal. Chem. 84, 1146-1151( 2012) reported that toluene used as a solvent was the proton source for polyaromatic hydrocarbon compounds (PAHs) that were subjected to (+)-mode atmospheric-pressure photoionization. In the current study, the exact position of the hydrogen atom in the toluene molecule (either a methyl hydrogen or an aromatic ring hydrogen) involved in the formation of protonated PAH ions was investigated. Experimental analyses of benzene and anisole demonstrated that although the aromatic hydrogen atom of toluene did not contribute to the formation of protonated anthracene, it did contribute to the formation of protonated acridine. Thermochemical data and quantum mechanical calculations showed that the protonation of anthracene by an aromatic ring hydrogen atom of toluene is endothermic, while protonation by a methyl hydrogen atom is exothermic. However, protonation of acridine by either an aromatic ring hydrogen or a methyl hydrogen atom of toluene is exothermic. The different behavior of acridine and anthracene was attributed to differences in gas-phase basicity. It was concluded that both types of hydrogen in toluene can be used for protonation of PAH compounds, but a methyl hydrogen atom is preferred, especially for non-basic compounds.

  5. Magnetic ring for stripping enhancement

    International Nuclear Information System (INIS)

    Selph, F.

    1992-10-01

    A ring designed to recycle ions through a stripping medium offers the possibility for increasing output of the desired charge state by up to 4x. This could be a very important component of a Radioactive Nuclear Beam Facility. In order for such a ring to work effectively it must satisfy certain design conditions. These include achromaticity at the stripper, a dispersed region for an extraction magnet, and a number of first and higher order optics constraints which are necessary to insure that the beam emittance is not degraded unduly by the ring. An example is given of a candidate design of a stripping ring

  6. Source characterization using compound composition and stable carbon isotope ratio of PAHs in sediments from lakes, harbor, and shipping waterway

    International Nuclear Information System (INIS)

    Kim, Moonkoo; Kennicutt, Mahlon C.; Qian, Yaorong

    2008-01-01

    Molecular compositions and compound specific stable carbon isotope ratios of polycyclic aromatic hydrocarbons (PAH) isolated from sediments were used to characterize possible sources of contamination at an urban lake, a harbor, a shipping waterway, and a relatively undisturbed remote lake in the northwest United States. Total PAH concentrations in urban lake sediments ranged from 66.0 to 16,500 μg g -1 dry wt. with an average of 2600 μg g -1 , which is ∼ 50, 100, and 400 times higher on average than PAH in harbor (48 μg g -1 on average), shipping waterway (26 μg g -1 ), and remote lake (7 μg g -1 ) sediments, respectively. The PAH distribution patterns, methyl phenanthrene/phenanthrene ratios, and a pyrogenic index at the sites suggest a pyrogenic origin for PAHs. Source characterization using principal component analysis and various molecular indices including C2-dibenzothiophenes/C2-phenanthrenes, C3-dibenzothiophenes/C3-phenanthrenes, and C2-chrysenes/C2-phenanthrenes ratios, was able to differentiate PAH deposited in sediments from the four sites. The uniqueness of the source of the sediment PAHs from urban lake was also illustrated by compound specific stable carbon isotope analysis. It was concluded that urban lake sediments are accumulating PAH from sources that are unique from contamination detected at nearby sites in the same watershed

  7. Urban sprawl leaves its PAH signature

    Science.gov (United States)

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

    2000-01-01

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

  8. Concentrations of PAHs (Polycyclicaromatic Hydrocarbons Pollutant in Sediment of The Banten Bay

    Directory of Open Access Journals (Sweden)

    Khozanah Munawir

    2018-02-01

    Full Text Available Banten Bay is end of stream for a few rivers from Banten mainland where many manufactures and petrochemical industries are built. This may give environmental pressure of water quality of the bay due to pollutant input, such as Polycyclic Aromatic Hydrocarbons (PAHs. This study is to identify those pollutants and determine their total concentration and distribution in sediments. Surface sediment samples were collected in four zones: inner coastline within the bay, middle bay, coastline off the bay and outer of the Bay in April 2016. PAH components were extracted and measured using a gas chromatography-mass spectrometry. Levels of total PAHs in sediments in inner coastline within the bay ranged between 0.381-2.654 ppm with an average of 1.288 ppm, middle of the bay ranged between 0.747-1.762 ppm with an average of 1.198 ppm, outer of the bay ranged between 0.192-1.394 ppm with an average of 0.921 ppm, and east coast of the bay ranged between 0.191-1.394 ppm and an average of 0.778 ppm. The levels of total PAH contamination is apparently lower than those of PAH threshold in sediments (i.e. 4.5 ppm. Keywords: PAHs (Polycyclic Aromatic Hydrocarbons, Banten Bay

  9. Concentrations, input prediction and probabilistic biological risk assessment of polycyclic aromatic hydrocarbons (PAHs) along Gujarat coastline.

    Science.gov (United States)

    Gosai, Haren B; Sachaniya, Bhumi K; Dudhagara, Dushyant R; Rajpara, Rahul K; Dave, Bharti P

    2018-04-01

    A comprehensive investigation was conducted in order to assess the levels of PAHs, their input prediction and potential risks to bacterial abundance and human health along Gujarat coastline. A total of 40 sediment samples were collected at quarterly intervals within a year from two contaminated sites-Alang-Sosiya Shipbreaking Yard (ASSBRY) and Navlakhi Port (NAV), situated at Gulf of Khambhat and Gulf of Kutch, respectively. The concentration of ΣPAHs ranged from 408.00 to 54240.45 ng g -1  dw, indicating heavy pollution of PAHs at both the contaminated sites. Furthermore, isomeric ratios and principal component analysis have revealed that inputs of PAHs at both contaminated sites were mixed-pyrogenic and petrogenic. Pearson co-relation test and regression analysis have disclosed Nap, Acel and Phe as major predictors for bacterial abundance at both contaminated sites. Significantly, cancer risk assessment of the PAHs has been exercised based on incremental lifetime cancer risks. Overall, index of cancer risk of PAHs for ASSBRY and NAV ranged from 4.11 × 10 -6 -2.11 × 10 -5 and 9.08 × 10 -6 -4.50 × 10 -3 indicating higher cancer risk at NAV compared to ASSBRY. The present findings provide baseline information that may help in developing advanced bioremediation and bioleaching strategies to minimize biological risk.

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

    Science.gov (United States)

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

    2012-01-01

    The concentration of polycyclic aromatic hydrocarbons (PAHs) and the toxicity to marine bacteria (Vibrio fischeri) were measured for the organic solvent extracts of sea sediments collected from an urban watershed area (Hiroshima Bay) of Japan and compared with the concentrations and toxicity of atmospheric particulate matter (PM). In atmospheric PM, the PAHs concentration was highest in fine particulate matter (FPM) collected during cold seasons. The concentrations of sea sediments were 0.01-0.001 times those of atmospheric PM. 1/EC50 was 1-10 L g(-1) PM for atmospheric PM and 0.1-1 L g(-1) dry solids for sea sediments. These results imply that toxic substances from atmospheric PM are diluted several tens or hundreds of times in sea sediments. The ratio of the 1/EC50 to PAHs concentration ((1/EC50)/16PAHs) was stable for all sea sediments (0.1-1 L μg(-1) 16PAHs) and was the same order of magnitude as that of FPM and coarse particulate matter (CPM). The ratio of sediments collected from the west was more similar to that of CPM while that from the east was more similar to FPM, possibly because of hydraulic differences among water bodies. The PAHs concentration pattern analyses (principal component analysis and isomer ratio analysis) were conducted and the results showed that the PAHs pattern in sea sediments was quite different to that of FPM and CPM. Comparison with previously conducted PAHs analyses suggested that biomass burning residues comprised a major portion of these other sources.

  11. A PAH growth mechanism and synergistic effect on PAH formation in counterflow diffusion flames

    KAUST Repository

    Wang, Yu

    2013-09-01

    A reaction mechanism having molecular growth up to benzene for hydrocarbon fuels with up to four carbon-atoms was extended to include the formation and growth of polycyclic aromatic hydrocarbons (PAHs) up to coronene (C24H12). The new mechanism was tested for ethylene premixed flames at low (20torr) and atmospheric pressures by comparing experimentally observed species concentrations with those of the computed ones for small chemical species and PAHs. As compared to several existing mechanisms in the literature, the newly developed mechanism showed an appreciable improvement in the predicted profiles of PAHs. The new mechanism was also used to simulate PAH formation in counterflow diffusion flames of ethylene to study the effects of mixing propane and benzene in the fuel stream. In the ethylene-propane flames, existing experimental results showed a synergistic effect in PAH concentrations, i.e. PAH concentrations first increased and then decreased with increasing propane mixing. This PAH behavior was successfully captured by the new mechanism. The synergistic effect was predicted to be more pronounced for larger PAH molecules as compared to the smaller ones, which is in agreement with experimental observations. In the experimental study in which the fuel stream of ethylene-propane flames was doped with benzene, a synergistic effect was mitigated for benzene, but was observed for large PAHs. This effect was also predicted in the computed PAH profiles for these flames. To explain these responses of PAHs in the flames of mixture fuels, a pathway analysis has been conducted, which show that several resonantly stabilized species as well as C4H4 and H atom contribute to the enhanced synergistic behaviors of larger PAHs as compared to the small ones in the flames of mixture fuels. © 2013 The Combustion Institute.

  12. Storage Rings

    International Nuclear Information System (INIS)

    Fischer, W.

    2010-01-01

    Storage rings are circular machines that store particle beams at a constant energy. Beams are stored in rings without acceleration for a number of reasons (Tab. 1). Storage rings are used in high-energy, nuclear, atomic, and molecular physics, as well as for experiments in chemistry, material and life sciences. Parameters for storage rings such as particle species, energy, beam intensity, beam size, and store time vary widely depending on the application. The beam must be injected into a storage ring but may not be extracted (Fig. 1). Accelerator rings such as synchrotrons are used as storage rings before and after acceleration. Particles stored in rings include electrons and positrons; muons; protons and anti-protons; neutrons; light and heavy, positive and negative, atomic ions of various charge states; molecular and cluster ions, and neutral polar molecules. Spin polarized beams of electrons, positrons, and protons were stored. The kinetic energy of the stored particles ranges from 10 -6 eV to 3.5 x 10 12 eV (LHC, 7 x 10 12 eV planned), the number of stored particles from one (ESR) to 1015 (ISR). To store beam in rings requires bending (dipoles) and transverse focusing (quadrupoles). Higher order multipoles are used to correct chromatic aberrations, to suppress instabilities, and to compensate for nonlinear field errors of dipoles and quadrupoles. Magnetic multipole functions can be combined in magnets. Beams are stored bunched with radio frequency systems, and unbunched. The magnetic lattice and radio frequency system are designed to ensure the stability of transverse and longitudinal motion. New technologies allow for better storage rings. With strong focusing the beam pipe dimensions became much smaller than previously possible. For a given circumference superconducting magnets make higher energies possible, and superconducting radio frequency systems allow for efficient replenishment of synchrotron radiation losses of large current electron or positron beams

  13. Polysykliske aromatiske hydrokarboner (PAH) i fisk

    OpenAIRE

    Knutzen, J.

    1987-01-01

    Det er sammenstilt litteraturdata om polysykliske aromatiske hydrokarboner (PAH, tjærestoffer) i fisk fra et lite påvirkede og fra forurensede områder og sammenlignet med utvalgte data for PAH i røkt fisk. På grunn av sparsomt og delvis tvilsomt materiale, har det bare latt seg gjøre å antyde øvre grense for et "diffust bakgrunnsnivå" av benzo(a)pyren i fiskefilet: 1 µg/kg frisk vekt. Ofte har ikke total-PAH eller utvalgte PAH-forbindelser latt seg påvise, selv i områder som vites å være mark...

  14. Determination of polynuclear aromatic hydrocarbons (PAHs) in ...

    African Journals Online (AJOL)

    AJB SERVER

    2006-11-02

    Nov 2, 2006 ... Several water bodies in the Niger Delta region of Nigeria where extensive crude oil ..... hydrocarbons (PAHs) in fish from the Red Sea Coast of Yemem. ... smoked meat products and smoke flavouring food additives. J.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-10-01

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

  16. Characteristics of persistent spin current components in a quasi-periodic Fibonacci ring with spin–orbit interactions: Prediction of spin–orbit coupling and on-site energy

    International Nuclear Information System (INIS)

    Patra, Moumita; Maiti, Santanu K.

    2016-01-01

    In the present work we investigate the behavior of all three components of persistent spin current in a quasi-periodic Fibonacci ring subjected to Rashba and Dresselhaus spin–orbit interactions. Analogous to persistent charge current in a conducting ring where electrons gain a Berry phase in presence of magnetic flux, spin Berry phase is associated during the motion of electrons in presence of a spin–orbit field which is responsible for the generation of spin current. The interplay between two spin–orbit fields along with quasi-periodic Fibonacci sequence on persistent spin current is described elaborately, and from our analysis, we can estimate the strength of any one of two spin–orbit couplings together with on-site energy, provided the other is known. - Highlights: • Determination of Rashba and Dresselhaus spin–orbit fields is discussed. • Characteristics of all three components of spin current are explored. • Possibility of estimating on-site energy is given. • Results can be generalized to any lattice models.

  17. Characteristics of persistent spin current components in a quasi-periodic Fibonacci ring with spin–orbit interactions: Prediction of spin–orbit coupling and on-site energy

    Energy Technology Data Exchange (ETDEWEB)

    Patra, Moumita; Maiti, Santanu K., E-mail: santanu.maiti@isical.ac.in

    2016-12-15

    In the present work we investigate the behavior of all three components of persistent spin current in a quasi-periodic Fibonacci ring subjected to Rashba and Dresselhaus spin–orbit interactions. Analogous to persistent charge current in a conducting ring where electrons gain a Berry phase in presence of magnetic flux, spin Berry phase is associated during the motion of electrons in presence of a spin–orbit field which is responsible for the generation of spin current. The interplay between two spin–orbit fields along with quasi-periodic Fibonacci sequence on persistent spin current is described elaborately, and from our analysis, we can estimate the strength of any one of two spin–orbit couplings together with on-site energy, provided the other is known. - Highlights: • Determination of Rashba and Dresselhaus spin–orbit fields is discussed. • Characteristics of all three components of spin current are explored. • Possibility of estimating on-site energy is given. • Results can be generalized to any lattice models.

  18. Analysis of PAH in soil samples

    International Nuclear Information System (INIS)

    Haeufel, J.; Weisweiler, W.

    1994-01-01

    The supercritical fluid extraction of polycyclic aromatic hydrocarbons (PAH) from soil samples is described. Carbon dioxide mixed with a small amount of methanol is used for solvent. The results are compared with those obtained by a classical extraction method (that means with the use of organic liquids). The extracted PAH from both procedures can be separated by HPLC and analyzed with UV- and fluorescence detection. (orig.) [de

  19. Topological rings

    CERN Document Server

    Warner, S

    1993-01-01

    This text brings the reader to the frontiers of current research in topological rings. The exercises illustrate many results and theorems while a comprehensive bibliography is also included. The book is aimed at those readers acquainted with some very basic point-set topology and algebra, as normally presented in semester courses at the beginning graduate level or even at the advanced undergraduate level. Familiarity with Hausdorff, metric, compact and locally compact spaces and basic properties of continuous functions, also with groups, rings, fields, vector spaces and modules, and with Zorn''s Lemma, is also expected.

  20. Ring accelerators

    International Nuclear Information System (INIS)

    Gisler, G.; Faehl, R.

    1983-01-01

    We present two-dimensional simulations in (r-z) and r-theta) cylinderical geometries of imploding-liner-driven accelerators of rings of charged particles. We address issues of azimuthal and longitudinal stability of the rings. We discuss self-trapping designs in which beam injection and extraction is aided by means of external cusp fields. Our simulations are done with the 2-1/2-D particle-in-cell plasma simulation code CLINER, which combines collisionless, electromagnetic PIC capabilities with a quasi-MHD finite element package

  1. Piston ring lubrication and hydrocarbon emissions from internal combustion engines

    Energy Technology Data Exchange (ETDEWEB)

    Froelund, K.

    1997-11-01

    Is it the intention with this project to improve the existing hydrocarbon emission model at the Institute by combining it with a model for predicting the piston ring lubrication. The piston ring lubrication model should be experimentally verified to ensure the validity of the model. The following items were the objectives of the current study: Develop a piston ring lubrication model. This implies the development of a ring-pack gas flow model; Examine the response of the piston ring lubrication model to changing engineer conditions. Especially, it would be interesting to look at the engine warm-up phase since this is the phase where the engine-out emissions are highest and where the commonly used three way catalyst is not capable of converting the engine-out emissions, thereby leading the engine-out emissions directly out in to the environment with the exhaust gases; In order to verify the piston ring lubrication model the lubricant distribution on the cylinder liner should be investigated experimentally. Here again it would be of great interesting to look at the engine warm-up phase; The piston ring lubrication model should be adjusted for application together with the new hydrocarbon emission model for SI-engines at the Institute in order to increase the accuracy of the latter; The piston ring lubrication model could be used for describing the transport of PAH`s in diesel engines. (EG)

  2. PAH Spectroscopy: Past, Present and Future

    Science.gov (United States)

    Mattioda, Andrew

    2016-01-01

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

  3. Effects of low concentration biodiesel blends application on modern passenger cars. Part 3: Impact on PAH, nitro-PAH, and oxy-PAH emissions

    International Nuclear Information System (INIS)

    Karavalakis, Georgios; Fontaras, Georgios; Ampatzoglou, Dimitrios; Kousoulidou, Marina; Stournas, Stamoulis; Samaras, Zissis; Bakeas, Evangelos

    2010-01-01

    This study explores the impact of five different types of methyl esters on polycyclic aromatic hydrocarbon (PAH), nitrated-PAH and oxygenated PAH emissions. The measurements were conducted on a chassis dynamometer, according to the European regulation. Each of the five different biodiesels was blended with EN590 diesel at a proportion of 10-90% v/v (10% biodiesel concentration). The vehicle was a Euro 3 compliant common-rail diesel passenger car. Emission measurements were performed over the NEDC and compared with those of the real traffic-based Artemis driving cycles. The experimental results showed that the addition of biodiesel led to some important increases in low molecular-weight PAHs (phenanthrene and anthracene) and to both increases and reductions in large PAHs which are characterised by their carcinogenic and mutagenic properties. Nitro-PAHs were found to reduce with biodiesel whereas oxy-PAH emissions presented important increases with the biodiesel blends. The impact of biodiesel source material was particularly clear on the formation of PAH compounds. It was found that most PAH emissions decreased as the average load and speed of the driving cycle increased. Cold-start conditions negatively influenced the formation of most PAH compounds. A similar trend was observed with particulate alkane emissions. - This investigation is a contribution to the understanding the impact of different biodiesels on the formation of PAHs, nitro-PAHs and oxy-PAHs over different driving conditions.

  4. Effect-directed analysis and mixture effects of AhR-active PAHs in crude oil and coastal sediments contaminated by the Hebei Spirit oil spill

    International Nuclear Information System (INIS)

    Hong, Seongjin; Lee, Sangwoo; Choi, Kyungho; Kim, Gi Beum; Ha, Sung Yong; Kwon, Bong-Oh; Ryu, Jongseong; Yim, Un Hyuk; Shim, Won Joon; Jung, Jinho; Giesy, John P.; Khim, Jong Seong

    2015-01-01

    The major AhR-active PAHs were identified in crude oil and oil-contaminated sediments by use of effect-directed analysis. As part of the study, an enhanced potency balance analysis was conducted by establishing the novel relative potency values of (alkyl)-PAHs from the H4IIE-luc bioassay. Silica gel column fractionation of crude oil resulted in greater AhR-mediated potencies in fractions of aromatics (F2) and resins (F3), and such trend was also observed for field collected sediment samples. AhR-mediated potencies of six F2 sub-fractions from HPLC indicated that the majority of F2 responses were attributable to 3–4 ring aromatics. Target PAHs including C4-phenanthrene, C1-chrysene, and C3-chrysene in sediments explained ∼18% of the bioassay-derived TCDD-EQs, however, the unknown AhR agonists and potential mixture effects remain in question. Overall, the AhR-potency and antagonistic potential of residual oil in sediment tended to decrease over time, thus monitoring of weathering process would be key for the post management of oil-contaminated sites. - Highlights: • AhR-active PAHs in crude oil and sediments were newly determined using EDA. • Novel relative potency values of (alkyl)-PAHs for AhR activity were established. • Three to four ring PAHs were identified to be major AhR agonists in crude oil. • Parent and alkyl-PAHs explained ∼18% of the total AhR-mediated potencies of crude oil. • AhR-mediated potencies apparently decreased by the timely weathering processes. - “Major AhR agonists were identified three to four ring PAHs in crude oil and sediments determined by use of effect-directed analysis.”

  5. Ring interferometry

    CERN Document Server

    Malykin, Grigorii B; Zhurov, Alexei

    2013-01-01

    This monograph is devoted to the creation of a comprehensive formalism for quantitative description of polarized modes' linear interaction in modern single-mode optic fibers. The theory of random connections between polarized modes, developed in the monograph, allows calculations of the zero shift deviations for a fiber ring interferometer. The monograph addresses also the

  6. Infrared spectra of interstellar deuteronated PAHs

    Science.gov (United States)

    Buragohain, Mridusmita; Pathak, Amit; Sarre, Peter

    2015-08-01

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

  7. Build/Couple/Pair Strategy Combining the Petasis 3-Component Reaction with Ru-Catalyzed Ring-Closing Metathesis and Isomerization

    DEFF Research Database (Denmark)

    Ascic, Erhad; Le Quement, Sebastian Thordal; Ishøy, Mette

    2012-01-01

    A “build/couple/pair” pathway for the systematic synthesis of structurally diverse small molecules is presented. The Petasis 3-component reaction was used to synthesize anti-amino alcohols displaying pairwise reactive combinations of alkene moieties. Upon treatment with a ruthenium alkylidene...

  8. Ligninolytic basidiomycetes as promising organisms for the mycoremediation of PAH-contaminated Environments

    Science.gov (United States)

    Pozdnyakova, N. N.; Balandina, S. A.; Dubrovskaya, E. V.; Golubev, C. N.; Turkovskaya, O. V.

    2018-01-01

    Primary screening of ligninolytic fungi belonging to wood- and soil-inhabiting basidiomycetes revealed their ability to degrade three-ringed PAHs with formation of quinone metabolites at the first stage. The degradative activity was both species and strain specific, and some differences in the “chances” for the formed quinones were found. They were the main end metabolites in the degradation of PAHs by Stropharia rugosoannulata and Agaricus bisporus. During PAH degradation by strains of Trametes versicolor, Pleurotus ostreatus, Schizophyllum commune, and Bjerkandera adusta similar metabolites were detected during the cultivation, but they were utilized further. The results supported the hypothesis that the degree of PAH degradation may depend on the composition of the extracellular ligninolytic complex of the fungi: in the presence of a single ligninolytic enzyme, laccase, the accumulation of quinone metabolites takes place; their further utilization is possible with the participation of ligninolytic peroxidases. The data obtained showed the necessity not only to identify the metabolites formed, but also to study the activity of the basic ligninolytic enzymes. It is important for the correct selection of fungal strains for mycoremediation.

  9. PAHs distribution in sediments associated with gas hydrate and oil seepage from the Gulf of Mexico.

    Science.gov (United States)

    Wang, Cuiping; Sun, Hongwen; Chang, Ying; Song, Zhiguang; Qin, Xuebo

    2011-12-01

    Six sediment samples collected from the Gulf of Mexico were analyzed. Total concentrations of the PAHs ranged from 52 to 403 ng g(-1) dry weight. The lowest PAH concentration without 5-6 rings PAHs appeared in S-1 sample associated with gas hydrate or gas venting. Moreover, S-1 sample had the lowest organic carbon content with 0.85% and highest reduced sulfur level with 1.21% relative to other samples. And, analysis of the sources of PAHs in S-1 sample indicated that both pyrogenic and petrogenic sources, converserly, while S-8, S-10 and S-11 sample suggested petrogenic origin. The distribution of dibenzothiophene, fluorine and dibenzofuran and the maturity parameters of triaromatic steranes suggested that organic matters in S-1 sample were different from that in S-8, S-10 and S-11 sample. This study suggested that organic geochemical data could help in distinguish the characteristic of sediment associated with gas hydrate or with oil seepage. Copyright © 2011 Elsevier Ltd. All rights reserved.

  10. Do 16 Polycyclic Aromatic Hydrocarbons Represent PAH Air Toxicity?

    Science.gov (United States)

    Samburova, Vera; Zielinska, Barbara; Khlystov, Andrey

    2017-08-15

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

  11. Micellar Enhanced Ultrafiltration for the Removal of Polycyclic Aromatic Hydrocarbons (PAHs Mixtures in Underground Contaminated Water in Oman

    Directory of Open Access Journals (Sweden)

    Mohamed Aoudia

    2011-12-01

    Full Text Available In an attempt to analyze polycyclic aromatic hydrocarbons (PAHs in diesel contaminated underground water in Oman (Rustaq, Gas chromatography-Mass spectrometry was first used to determine the different concentrations in a standard mixture containing 16 PAHs. Retention time and calibration curves were obtained for all aromatic compounds and were used to identify a given analyte as well as its concentration in the contaminated underground water. Micellar enhanced ultrafiltration (MEUF was then used to treat standard aqueous solution of PAHs at low concentration (~ 1 ppb using an edible nonionic surfactant (Tween 80. The totality of the mixture components was completely rejected. Within the experimental detection limit (± 0.01 ppb, the residual PAH concentrations were less than 0.01 ppb in accord with the allowed concentrations in drinking water. Likewise, excellent rejections of PAHs in MEUF treatment of diesel contaminated underground water at an Omani site (Rustaq were observed. The concentration of PAHs was reduced to less than 0.01 ppb, the accepted limit for the most toxic member of the PAH group (benzo(apyrene.

  12. Anxiety, Depression, and Health-Related QOL in Patients Diagnosed with PAH or CTEPH.

    Science.gov (United States)

    Pfeuffer, Elena; Krannich, Holger; Halank, Michael; Wilkens, Heinrike; Kolb, Philipp; Jany, Berthold; Held, Matthias

    2017-12-01

    Pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) are life-threatening diseases with a high burden of symptoms. Although depression, anxiety, and reduced health related quality of life (HRQOL) have also been reported, a comparative analysis which explores these traits and their underlying factors was lacking. A retrospective analysis of depression, anxiety, and health related QOL was conducted using a Hospital anxiety and depression scale (HADS) as well as the SF-36 HRQOL questionnaire. Results from these tools were compared with haemodynamic and functional parameters in 70 PAH and 23 CTEPH outpatients from a German tertiary care center specializing in pulmonary hypertension. Although HRQOL was reduced in both cohorts of patients, individuals diagnosed with CTEPH scored lower in nearly all SF-36 parameters. Significance was noted in both "mental health" (p = 0.01) and "mental component summary score" (MCS) (p = 0.02). Depression was also more frequent in patients with CTEPH (56%) than in patients with PAH (30%), (p = 0.03). Overall, depression and anxiety correlated with most SF-36 scales in both PAH and CTEPH. In CTEPH, depression also correlated with the Borg Dyspnea Scale (r = 0.44, p = 0.01). These patients also had significantly lower pCO 2 levels than the PAH cohort reflecting more severe ventilation/perfusion mismatch. All other haemodynamic and functional parameters did not differ across the groups. While both cohorts of patients suffer from a reduced HRQOL as well as depression and anxiety, decreases in mental health parameters are more pronounced in the CTEPH cohort. This suggests a strong effort to improve early detection, especially in dyspneic patients with classical risk factors for CTEPH and PAH and argues for mental illness interventions alongside routine clinical care provided to patients diagnosed with PAH or CTEPH.

  13. Evaluation of ring impedance of the Photon Factory storage ring

    International Nuclear Information System (INIS)

    Kiuchi, T.; Izawa, M.; Tokumoto, S.; Hori, Y.; Sakanaka, S.; Kobayashi, M.; Kobayakawa, H.

    1992-05-01

    The loss parameters of the ducts in the Photon Factory (PF) storage ring were evaluated using the wire method and the code TBCI. Both the measurement and the calculation were done for a different bunch length (σ) ranging from 23 to 80 ps. The PF ring impedance was estimated to be |Z/n|=3.2 Ω using the broadband impedance model. The major contribution to the impedance comes from the bellows and the gate valve sections. Improvements of these components will lower the ring impedance by half. (author)

  14. 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

    Science.gov (United States)

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

    2014-01-01

    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

  15. Phyto remediation of PAH contaminated soil

    International Nuclear Information System (INIS)

    Petruzzelli, G.; Pedron, F.; Barbafieri, M.; Cervelli, St.; Vigna Guidi, G.

    2005-01-01

    Phyto-remediation may enhance degradation of organic compounds promoting an adequate substrate for microbial growth. The aim of this work was to evaluate the efficiency of two plant species, Lupinus albus and Zea mais, in the bio-remediation of a PAH contaminated soil. This soil has been collected in a contaminated industrial area in Italy characterized by PAH concentrations up to 16000 mg/Kg. Microcosms experiments were carried out by planting Lupinus albus and Zea mais in the polluted soil; controls without plants were run separately. Growing period lasted by three months. Plants favoured PAH biodegradation by percentages of 32% with Lupinus albus and 22% with Zea mais, with respect to non vegetated microcosms. (authors)

  16. Vertical distribution, composition profiles, sources and toxicity assessment of PAH residues in the reclaimed mudflat sediments from the adjacent Thane Creek of Mumbai.

    Science.gov (United States)

    Basavaiah, N; Mohite, R D; Singare, P U; Reddy, A V R; Singhal, R K; Blaha, U

    2017-05-15

    A study on vertical distribution of magnetic susceptibility, carcinogenic and endocrine disrupting PAHs was performed in the reclaimed mudflat sediments adjacent to the Thane Creek of Mumbai. The 5-rings PAHs and ΣC-PAHs were more dominant at 120cm depth contributing 52.23% and 60.19% respectively to ∑PAHs. The average ratio values of LMW/HMW PAHs (0.58); Fla/(Fla+Pyr) (0.50); Ant/(Ant+Phe) (0.50); BaA/(Chry+BaA) (0.48); BaP/BghiP (2.06), Phe/Ant (1.03) and BaA/Chr (0.93) indicate that the PAH contamination might have raised due to inefficient combustion and pyrogenic emissions during the open burning of solid waste in the vicinity. This was further supported by the anthropogenic ferri(o)magnetic loading over the last 100years influencing the Creek sediments. The PAHs toxicity estimation was performed by calculating the toxic equivalent quantity (TEQ) value of 8.62ng TEQ/g which was below the safe level (600ng TEQ/g) suggested by the Canadian risk-based soil criterion for protection of human health. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Bioremediation of PAH-contamined soils: Consequences on formation and degradation of polar-polycyclic aromatic compounds and microbial community abundance.

    Science.gov (United States)

    Biache, Coralie; Ouali, Salma; Cébron, Aurélie; Lorgeoux, Catherine; Colombano, Stéfan; Faure, Pierre

    2017-05-05

    A bioslurry batch experiment was carried out over five months on three polycyclic aromatic compound (PAC) contaminated soils to study the PAC (PAH and polar-PAC) behavior during soil incubation and to evaluate the impact of PAC contamination on the abundance of microbial communities and functional PAH-degrading populations. Organic matter characteristics and reactivity, assessed through solvent extractable organic matter and PAC contents, and soil organic matter mineralization were monitored during 5 months. Total bacteria and fungi, and PAH-ring hydroxylating dioxygenase genes were quantified. Results showed that PAHs and polar-PACs were degraded with different degradation dynamics. Differences in degradation rates were observed among the three soils depending on PAH distribution and availability. Overall, low molecular weight compounds were preferentially degraded. Degradation selectivity between isomers and structurally similar compounds was observed which could be used to check the efficiency of bioremediation processes. Bacterial communities were dominant over fungi and were most likely responsible for PAC degradation. Abundance of PAH-degrading bacteria increased during incubations, but their proportion in the bacterial communities tended to decrease. The accumulation of some oxygenated-PACs during the bioslurry experiment underlines the necessity to monitor these compounds during application of remediation treatment on PAH contaminated soils. Copyright © 2017 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    2015-12-01

    In order to investigate the internal exposure levels of polycyclic aromatic hydrocarbons (PAHs) in primary school students of Guangzhou, the research collected urine of 78 and 86 primary school students from two primary schools in the summer of 2014, one school located in the ordinary residential area and the other in the industrial area. The contents of 10 kinds of OH-PAHs were tested by the rapid liquid chromatography coupled to triple quadruple tandem mass spectrometry. The results showed that the concentrations of total OH-PAHs in primary school students in the residential zone ranged from 0.83 µmol · mol⁻¹ to 80.63 µmol · mol⁻¹, while those in industrial area ranged from 1.06 µmol · mol⁻¹ to 72.47 µmol · mol⁻¹. The geometric average concentrations were 6.18 µmol · mol⁻¹ and 6.47 µmol · mol⁻¹, respectively, and there was no statistical significance between them (P > 0.05). Comparison of the exposure levels of different components of PAHs in the two areas found that all the OH-PAHs had no significant difference except for the levels of 1- OHP (P transportation emissions.

  19. Identification of petroleum hydrocarbons using a reduced number of PAHs selected by Procrustes rotation.

    Science.gov (United States)

    Fernández-Varela, R; Andrade, J M; Muniategui, S; Prada, D; Ramírez-Villalobos, F

    2010-04-01

    Identifying petroleum-related products released into the environment is a complex and difficult task. To achieve this, polycyclic aromatic hydrocarbons (PAHs) are of outstanding importance nowadays. Despite traditional quantitative fingerprinting uses straightforward univariate statistical analyses to differentiate among oils and to assess their sources, a multivariate strategy based on Procrustes rotation (PR) was applied in this paper. The aim of PR is to select a reduced subset of PAHs still capable of performing a satisfactory identification of petroleum-related hydrocarbons. PR selected two subsets of three (C(2)-naphthalene, C(2)-dibenzothiophene and C(2)-phenanthrene) and five (C(1)-decahidronaphthalene, naphthalene, C(2)-phenanthrene, C(3)-phenanthrene and C(2)-fluoranthene) PAHs for each of the two datasets studied here. The classification abilities of each subset of PAHs were tested using principal components analysis, hierarchical cluster analysis and Kohonen neural networks and it was demonstrated that they unraveled the same patterns as the overall set of PAHs. (c) 2009 Elsevier Ltd. All rights reserved.

  20. A multimedia fate model to evaluate the fate of PAHs in Songhua River, China

    International Nuclear Information System (INIS)

    Wang Ce; Feng Yujie; Sun Qingfang; Zhao Shanshan; Gao Peng; Li Bailian

    2012-01-01

    A multimedia fate model coupling dynamic water flow with a level IV fugacity model has been developed and applied to simulate the temporal and spatial fate of Polycyclic Aromatic Hydrocarbons (PAHs) in the Songhua River, China. The model has two components: in the first, the one-dimensional network kinematic wave equation is used to calculate varying water flow and depth. In the second, Fugacity IV equations are implemented to predict contaminant distributions in four environmental media. The estimated concentrations of eight PAHs in Songhua River are obtained, and all simulated results are in acceptable agreement with monitoring data, as verified with the Theil’s inequality coefficient test. The sensitivity of PAH concentration in each environmental phase to input parameters are also evaluated. Our results show the model predicts reasonably accurate contaminant concentrations in natural rivers, and that it can be used to supply necessary information for control and management of water pollution. - Highlights: ► The model used was developed based on kinematic wave equation and level IV fugacity principle. ► The model was applied to describe the fate and transport of organic chemicals in natural river. ► The concentrations of PAHs in water column were satisfactorily simulated when compared with monitoring data. ► Temporal and spatial variability of PAHs concentration among multimedia environmental phases was illustrated. - A dynamic water flow based multimedia fate model is developed to characterize the fate and transport of organic contaminant in natural rivers.

  1. Analytical Evaluation to Determine Selected PAHs by HPLC in a Type 2 Fuel

    International Nuclear Information System (INIS)

    Garcia Alonso, S.; Perez Pastor, R. M.; Sevillano Castano, M. L.; Escolano Segovia, O.; Garcia Frutos, F. J.

    2009-01-01

    An evaluation of analytical parameters to determine selected PAHs in a fuel oil type II by HPLC coupled to fluorescence and diode detectors is presented. The study was focused on four conventional treatments of these kinds of oil samples and the main objective was giving a measure of confidence level of PAH results in the fuel oil. This study was performed in the frame of the project Assessment of natural attenuation of PAHs in agricultural soil contaminated with fuel from an accidental spill (Spanish National Plain I+D+I, CTM2007-64537). This paper is presented as follows: Analysis of reference material 1582 (NIST) by using the four kinds of sample treatments of interest. Application of variance analysis to compare results obtained from type II fuel by using each sample treatment and chromatographic detector. Finally, a statistic calculation was performed to measure uncertainty components in chromatographic analysis. (Author)

  2. Impact of clay mineral, wood sawdust or root organic matter on the bacterial and fungal community structures in two aged PAH-contaminated soils.

    Science.gov (United States)

    Cébron, Aurélie; Beguiristain, Thierry; Bongoua-Devisme, Jeanne; Denonfoux, Jérémie; Faure, Pierre; Lorgeoux, Catherine; Ouvrard, Stéphanie; Parisot, Nicolas; Peyret, Pierre; Leyval, Corinne

    2015-09-01

    The high organic pollutant concentration of aged polycyclic aromatic hydrocarbon (PAH)-contaminated wasteland soils is highly recalcitrant to biodegradation due to its very low bioavailability. In such soils, the microbial community is well adapted to the pollution, but the microbial activity is limited by nutrient availability. Management strategies could be applied to modify the soil microbial functioning as well as the PAH contamination through various amendment types. The impact of amendment with clay minerals (montmorillonite), wood sawdust and organic matter plant roots on microbial community structure was investigated on two aged PAH-contaminated soils both in laboratory and 1-year on-site pot experiments. Total PAH content (sum of 16 PAHs of the US-EPA list) and polar polycyclic aromatic compounds (pPAC) were monitored as well as the available PAH fraction using the Tenax method. The bacterial and fungal community structures were monitored using fingerprinting thermal gradient gel electrophoresis (TTGE) method. The abundance of bacteria (16S rRNA genes), fungi (18S rRNA genes) and PAH degraders (PAH-ring hydroxylating dioxygenase and catechol dioxygenase genes) was followed through qPCR assays. Although the treatments did not modify the total and available PAH content, the microbial community density, structure and the PAH degradation potential changed when fresh organic matter was provided as sawdust and under rhizosphere influence, while the clay mineral only increased the percentage of catechol-1,2-dioxygenase genes. The abundance of bacteria and fungi and the percentage of fungi relative to bacteria were enhanced in soil samples supplemented with wood sawdust and in the plant rhizospheric soils. Two distinct fungal populations developed in the two soils supplemented with sawdust, i.e. fungi related to Chaetomium and Neurospora genera and Brachyconidiellopsis and Pseudallescheria genera, in H and NM soils respectively. Wood sawdust amendment favoured the

  3. Polycyclic Aromatic Hydrocarbons (PAHs) and Hopanes in Plastic Resin Pellets as Markers of Oil Pollution via International Pellet Watch Monitoring.

    Science.gov (United States)

    Yeo, Bee Geok; Takada, Hideshige; Hosoda, Junki; Kondo, Atsuko; Yamashita, Rei; Saha, Mahua; Maes, Thomas

    2017-08-01

    Oil pollution in the marine environment is an unavoidable problem due to chronic input from local sources, particularly in urban areas and oil spills. Oil pollution not only causes immediate physical damages to surrounding wildlife but also some components, including higher molecular weight PAHs, can persist in the environment for many years and pose insidious threats to the ecosystem. Long-term and nontargeted monitoring of oil pollution is important. This paper examines the ability of International Pellet Watch (IPW) for initial identification and monitoring of oil pollution by analysing PAHs and hopanes in plastic pellet samples collected globally by volunteers. PAH concentrations with the sum of 28 parent and methyl PAHs vary geographically, ranging from 0.035 to 24.4 µg/g-pellet, in line with the presence or absence of local oil pollution sources, such as oil refineries or oil spill sites. This suggests that PAHs can be used to monitor petroleum pollution in IPW. A colour-coded categorization for PAH concentrations within IPW monitoring also is established to facilitate data presentation and understanding. PAH concentrations are generally higher in Western Europe, especially around the North Sea shorelines, moderate in East Asia and North America, and lower in South East Asia, Oceania, South America, and Africa. Hopane concentrations, with a smaller spatial variation (1.7-101 µg/g-pellet), showed no spatial pattern. This result and the poor correlation between hopanes and PAHs suggest that hopane concentrations alone are unsuited to identify petroleum pollution. However, hopane compositions can be used for fingerprinting sources of oil pollution. Thus, both PAHs and hopanes in IPW allow for low cost, remote monitoring of global oil pollution.

  4. Effect of rhamnolipids on the uptake of PAHs by ryegrass

    International Nuclear Information System (INIS)

    Zhu Lizhong; Zhang Ming

    2008-01-01

    A hydroponic experiment was conducted to investigate the effect of rhamnolipids, a biosurfactant, on the uptake of polycyclic aromatic hydrocarbons (PAHs) by ryegrass. Results showed that rhamnolipids could enhance the uptake of PAHs by ryegrass roots. With increasing concentration of rhamnolipids, the PAH content in ryegrass roots initially increased and then decreased, while the PAH content in ryegrass shoots did not change. Batch studies also showed that the sorption of phenanthrene by fresh ryegrass roots was dependent on rhamnolipid concentration and showed the same trends as the uptake experiment. The increase of permeability of ryegrass root cells with the increase of rhamnolipid concentration may lead to the initial enhancement of PAH content in ryegrass roots, and the decrease of PAH adsorption onto the root surface with further increase of rhamnolipids led to the decrease of PAH content in ryegrass roots. - Rhamnolipids, a biosurfactant, can promote the uptake of PAHs by ryegrass, which indicates a potential application of surfactant-enhanced phytoremediation

  5. Effect of rhamnolipids on the uptake of PAHs by ryegrass

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Lizhong [Department of Environmental Science, Zhejiang University, Hangzhou, Zhejiang 310028 (China); Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, Zhejiang University, Hangzhou, Zhejiang 310029 (China)], E-mail: zlz@zju.edu.cn; Zhang Ming [Department of Environmental Science, Zhejiang University, Hangzhou, Zhejiang 310028 (China)], E-mail: zhangming@zju.edu.cn

    2008-11-15

    A hydroponic experiment was conducted to investigate the effect of rhamnolipids, a biosurfactant, on the uptake of polycyclic aromatic hydrocarbons (PAHs) by ryegrass. Results showed that rhamnolipids could enhance the uptake of PAHs by ryegrass roots. With increasing concentration of rhamnolipids, the PAH content in ryegrass roots initially increased and then decreased, while the PAH content in ryegrass shoots did not change. Batch studies also showed that the sorption of phenanthrene by fresh ryegrass roots was dependent on rhamnolipid concentration and showed the same trends as the uptake experiment. The increase of permeability of ryegrass root cells with the increase of rhamnolipid concentration may lead to the initial enhancement of PAH content in ryegrass roots, and the decrease of PAH adsorption onto the root surface with further increase of rhamnolipids led to the decrease of PAH content in ryegrass roots. - Rhamnolipids, a biosurfactant, can promote the uptake of PAHs by ryegrass, which indicates a potential application of surfactant-enhanced phytoremediation.

  6. Hydrogenated Benzene in Circumstellar Environments: Insights into the Photostability of Super-hydrogenated PAHs

    Science.gov (United States)

    Quitián-Lara, Heidy M.; Fantuzzi, Felipe; Nascimento, Marco A. C.; Wolff, Wania; Boechat-Roberty, Heloisa M.

    2018-02-01

    Polycyclic aromatic hydrocarbons (PAHs), comprised of fused benzene (C6H6) rings, emit infrared radiation (3–12 μm) due to the vibrational transitions of the C–H bonds of the aromatic rings. The 3.3 μm aromatic band is generally accompanied by the band at 3.4 μm assigned to the vibration of aliphatic C–H bonds of compounds such as PAHs with an excess of peripheral H atoms (H n –PAHs). Herein we study the stability of fully hydrogenated benzene (or cyclohexane, C6H12) under the impact of stellar radiation in the photodissociation region (PDR) of NGC 7027. Using synchrotron radiation and time-of-flight mass spectrometry, we investigated the ionization and dissociation processes at energy ranges of UV (10–200 eV) and soft X-rays (280–310 eV). Density Functional Theory (DFT) calculations were used to determine the most stable structures and the relevant low-lying isomers of singly charged C6H12 ions. Partial Ion Yield (PIY) analysis gives evidence of the higher tendency toward dissociation of cyclohexane in comparison to benzene. However, because of the high photoabsorption cross-section of benzene at the C1s resonance edge, its photodissociation and photoionization cross-sections are enhanced, leading to a higher efficiency of dissociation of benzene in the PDR of NGC 7027. We suggest that a similar effect is experienced by PAHs in X-ray photon-rich environments, which ultimately acts as an auxiliary protection mechanism of super-hydrogenated polycyclic hydrocarbons. Finally, we propose that the single photoionization of cyclohexane could enhance the abundance of branched molecules in interstellar and circumstellar media.

  7. Quantitative Analysis of Polycyclic Aromatic Hydrocarbons (PAHs Cited by the United States Food and Drug Administration

    Directory of Open Access Journals (Sweden)

    Guthery W

    2014-12-01

    Full Text Available The yields of 16 polycyclic aromatic hydrocarbons (PAHs were determined from cigarette mainstream smoke condensate extracts using Gas Chromatography- Tandem Mass Spectrometry (GC-MS/MS. The method has been validated for ISO and Health Canada Intense (HCI smoking protocols. Quantifiable levels (ISO means 0.16 to 365 ng/cig; HCI means 0.33 to 1595 ng/cig; n = 30 of 15 PAHs were found in the Kentucky reference cigarette K3R4F. The coefficient of variance (CV was derived from ten determinations each run in triplicate. The CV range was 8.7% to 24.8% (ISO and 6.6% to 24.3% (HCI. The limit of detection (LOD based on empirical precision was ≤ 0.06 ng/cig (ISO and ≤ 0.20 ng/cig (HCI for all components except naphthalene (2.89 and 9.62 ng/cig, respectively. The yields from 5 unspecified branded cigarettes (Samples A-E and 2 other reference cigarettes, K1R5F and the CORESTA monitor CM7, were determined under ISO smoking conditions. The same 15 PAHs were detected as in the K3R4F; however, cigarettes with lower yields of total particulate matter (TPM were found to contain significantly less PAHs. One component was measured below the limit of quantification (LOQ in Sample E and 2 components were < LOQ in the K1R5F.

  8. UV-Visible Spectra of PAHs and Derivatives Seeded in Supersonic Jet. Astrophysical Implications

    Science.gov (United States)

    Salma, Bejaoui; Salama, Farid

    2018-06-01

    Laboratory absorption spectra of Polycyclic Aromatic Hydrocarbons (PAHs) and PAH derivatives measured under astrophysical relevant conditions are crucial to test the PAHs-DIBs hypothesis as well as the PAH model for the IR emission bands. Our dedicated experimental setup on the COsmic SImulation Chamber (COSmIC) provides an excellent platform to study neutral and ionized PAHs under the low temperature and pressure conditions that are representative of interstellar environments [1]. In this work, we study the effect of the substitution of CH bond(s) by a nitrogen atom(s) on the electronic spectra of phenanthrene. The electronic transitions associated with the lower excited states of neutral phenanthrene (C14H10) and phenanthridine (C13H9N) are measured in gas phase in the 315-345 nm region. Molecules are seeded in a supersonic expansion of argon gas and the absorption spectra are measured using the Cavity Ring Down Spectroscopy (CRDS) technique. Additional measurements of the absorption spectra of phenanthrene, phenantridine and 1,10-phenanthroline (C12H8N2) isolated in 10 K argon matrices are also performed. The comparison between the CRDS spectra with the absorption of the matrix-isolated molecules highlight the matrix-induced perturbations in band position, profiles and broadening and illustrates the need of gas phase measurements for more accurate comparisons with astronomical spectra.[1] Salama, F., Galazutdinov, G., Krelowski, et al. ApJ 728, 154[FS1] (2011).[2] A. Tielens, ApJ 526 Pt 1265–273 (2008),Acknowledgements: This research is supported by the APRA Program of NASA SMD

  9. Photolysis of polycyclic aromatic hydrocarbons (PAHs) on Fe3+-montmorillonite surface under visible light: Degradation kinetics, mechanism, and toxicity assessments.

    Science.gov (United States)

    Zhao, Song; Jia, Hanzhong; Nulaji, Gulimire; Gao, Hongwei; Wang, Fu; Wang, Chuanyi

    2017-10-01

    Photochemical behavior of various polycyclic aromatic hydrocarbons (PAHs) on Fe 3+ -modified montmorillonite was explored to determine their potential kinetics, pathways, and mechanism under visible light. Depending on the type of PAH molecules, the transformation rate follows the order of benzo[a]pyrene ≈ anthracene > benzo[a]anthracene > phenanthrene. Quantum simulation results confirm the crucial role of "cation-π" interaction between Fe 3+ and PAHs on their transformation kinetics. Primary intermediates, including quinones, ring-opening products and benzene derivatives, were identified by gas chromatography-mass spectrometer (GC-MS), and the possible photodegradation pathway of benzo[a]pyrene was proposed. Meanwhile, radical intermediates, such as reactive oxygen species (ROS) and free organic radicals, were detected by electron paramagnetic resonance (EPR) technique. The photolysis of selected PAHs, such as anthracene and benzo[a]pyrene, on clay surface firstly occurs by electron transfer from PAHs to Fe 3+ -montmorillonite, followed by degradation involving photo-induced ROS such as ·OH and ·O 2 - . To investigate the acute toxicity of photolysis products, the Microtox ® toxicity test was performed during the photodegradation processes of various PAHs. As a result, the photo-irradiation initially induces increased toxicity by generating reactive intermediates, such as free organic radicals, and then the toxicity gradually decreases with increasing of reaction time. Overall, the present study provides useful information to understand the fate and photo-transformation of PAHs in contaminated soils. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. The rhizosphere and PAH amendment mediate impacts on functional and structural bacterial diversity in sandy peat soil

    International Nuclear Information System (INIS)

    Yrjaelae, Kim; Keskinen, Anna-Kaisa; Akerman, Marja-Leena; Fortelius, Carola; Sipilae, Timo P.

    2010-01-01

    To reveal the degradation capacity of bacteria in PAH polluted soil and rhizosphere we combined bacterial extradiol ring-cleavage dioxygenase and 16S rRNA analysis in Betula pubescens rhizoremediation. Characterisation of the functional bacterial community by RFLP revealed novel environmental dioxygenases, and their putative hosts were studied by 16S rRNA amplification. Plant rhizosphere and PAH amendment effects were detected by the RFLP/T-RFLP analysis. Functional species richness increased in the birch rhizosphere and PAH amendment impacted the compositional diversity of the dioxygenases and the structural 16S rRNA community. A shift from an Acidobacteria and Verrucomicrobia dominated to an Alpha- and Betaproteobacteria dominated community structure was detected in polluted soil. Clone sequence analysis indicated catabolic significance of Burkholderia in PAH polluted soil. These results advance our understanding of rhizoremediation and unveil the extent of uncharacterized functional bacteria to benefit bioremediation by facilitating the development of the molecular tool box to monitor bacterial populations in biodegradation. - The bacterial community analysis using 16S rRNA and extradiol dioxygenase marker genes in rhizoremediation revealed both a rhizosphere and a PAH-pollution effect.

  11. A PAH growth mechanism and synergistic effect on PAH formation in counterflow diffusion flames

    KAUST Repository

    Wang, Yu; Raj, Abhijeet Dhayal; Chung, Suk-Ho

    2013-01-01

    was tested for ethylene premixed flames at low (20torr) and atmospheric pressures by comparing experimentally observed species concentrations with those of the computed ones for small chemical species and PAHs. As compared to several existing mechanisms

  12. Polycyclic Aromatic Hydrocarbons (PAHs) Levels in Two ...

    African Journals Online (AJOL)

    Polycyclic aromatic hydrocarbons (PAHs) concentrations were measured by gas chromatography with flame ionization detector (GC/FID) in two fish species, Sardinella maderensis (Flat sardinella) and Galeoides decadactylus (Lesser African threadfin or Shine-nose or Common threadfin) from Ghanaian coastal waters and ...

  13. Determination of polynuclear aromatic hydrocarbons (PAHs) in ...

    African Journals Online (AJOL)

    AJB SERVER

    2006-11-02

    Nov 2, 2006 ... (PAHs) in selected water bodies in the Niger Delta. Chimezie Anyakora and ... production, foundries), transportation, burning (e.g. forest, straw, agriculture ..... the Red Sea Coast of Yemen (DouAbul et al., 1997), a comparable ...

  14. Distributions and Concentrations of PAHs in Hong Kong Soils

    International Nuclear Information System (INIS)

    Zhang, H.B.; Luo, Y.M.; Wong, M.H.; Zhao, Q.G.; Zhang, G.L.

    2006-01-01

    Surface soil (0-10 cm) samples from 53 sampling sites including rural and urban areas of Hong Kong were collected and analyzed for 16 EPA priority polycyclic aromatic hydrocarbons (PAHs). Total PAH concentrations were in the range of 7.0-410 μg kg -1 (dry wt), with higher concentrations in urban soils than that in rural soils. The three predominant PAHs were Fluoranthene, Naphthalene and Pyrene in rural soils, while Fluoranthene, Naphthalene and Benzo(b + k)fluoranthene dominated the PAHs of urban soils. The values of PAHs isomer indicated that biomass burning might be the major origin of PAHs in rural soils, but vehicular emission around the heavy traffic roads might contribute to the soil PAHs in urban areas. A cluster analysis was performed and grouped the detectable PAHs under 4 clusters, which could be indicative of the PAHs with different origins and PAHs affected by soil organic carbon contents respectively. - Baseline information is provided on levels, distributions and possible sources of PAHs in Hong Kong soils

  15. Modulation of ethoxyresorufin O-deethylase and glutathione S-transferase activities in Nile tilapia (Oreochromis niloticus) by polycyclic aromatic hydrocarbons containing two to four rings: implications in biomonitoring aquatic pollution.

    Science.gov (United States)

    Pathiratne, Asoka; Hemachandra, Chamini K

    2010-08-01

    Despite ubiquity of polycyclic aromatic hydrocarbons (PAHs) in the tropical environments, little information is available concerning responses of tropical fish to PAHs and associated toxicity. In the present study, effects of five PAHs containing two to four aromatic rings on hepatic CYP1A dependent ethoxyresorufin O-deethylase (EROD), glutathione S-transferase (GST) and serum sorbitol dehydrogenase (SDH) activities in Nile tilapia, a potential fish species for biomonitoring pollution in tropical waters, were evaluated. Results showed that EROD activities were induced by the PAHs containing four aromatic rings (pyrene and chrysene) in a dose dependent manner. However PAHs with two to three aromatic rings (naphthalene, phenanthrene and fluoranthene) caused no effect or inhibition of EROD activities depending on the dose and the duration. Fluoranthene was the most potent inhibitor. SDH results demonstrated that high doses of fluoranthene induced hepatic damage. GST activity was induced by the lowest dose of phenanthrene, fluoranthene and chrysene but high doses had no effect. The results indicate that induction of EROD enzyme in Nile tilapia is a useful biomarker of exposure to PAHs such as pyrene and chrysene. However EROD inhibiting PAHs such as fluoranthene in the natural environment may modulate the EROD inducing potential of other PAHs thereby influencing PAH exposure assessments.

  16. Source Apportionment of Background PAHs in the Peace-Athabasca Delta (Alberta, Canada) Using Molecular Level Radiocarbon Analysis.

    Science.gov (United States)

    Jautzy, Josué J; Ahad, Jason M E; Hall, Roland I; Wiklund, Johan A; Wolfe, Brent B; Gobeil, Charles; Savard, Martine M

    2015-08-04

    The downstream accumulation of polycyclic aromatic hydrocarbons (PAHs) in the Peace-Athabasca Delta (PAD), an ecologically important landscape, is a key issue of concern given the rapid development of the oil sands industry in Northern Alberta, Canada. In addition to PAHs derived from industrial activity (i.e., oil sands mining) within the Athabasca watershed, however, forest fires and erosion of fossil fuel deposits within both the Athabasca and Peace watersheds are two potentially important natural sources of PAHs delivered to the PAD. Consequently, evaluating the environmental impact of mining activities requires a quantitative understanding of natural, background PAHs. Here, we utilize molecular-level natural-abundance radiocarbon measurements on an amalgamated sediment record from a Peace River flood-susceptible oxbow lake in the northern Peace sector of the PAD to quantitatively discriminate sources of naturally occurring alkylated PAHs (fossil and modern biomass). A radiocarbon mass balance quantified a predominantly natural petrogenic source (93% petrogenic, 7% forest fire) for alkylated PAHs during the past ∼50 years. Additionally, a significant petrogenic component determined for retene, a compound usually considered a biomarker for softwood combustion, suggests that its use as a unique forest fire indicator may not be suitable in PAD sediments receiving Peace watershed-derived fluvial inputs.

  17. Use of advanced chemical fingerprinting in PAH source identification and allocation at a coal tar processing site

    International Nuclear Information System (INIS)

    Brown, J.S.; Boehm, P.D.; Douglas, G.S.

    1995-01-01

    Advanced chemical fingerprinting analyses were used to determine source allocation at a former coal tar processing facility which had been converted to a petroleum recycling site. Soil samples from the site had high petroleum hydrocarbon concentrations and elevated levels of polynuclear aromatic hydrocarbons (PAH). Comparisons of PAH distributions were used to differentiate the coal tar hydrocarbons from the petroleum hydrocarbons in soil samples. A more specific technique was needed to accurately allocate the contribution of the two sources to the observed PAH contamination in the soil. Petroleum biomarkers (steranes and triterpanes) which are present in crude oils and many refined petroleum products but are absent in coal tar were used to quantitatively allocate the source of the PAH contamination based on the relative ratio of the PAH to the biomarkers in soil samples. Using the resulting coal tar/petroleum source ratio the contribution of petroleum to the overall PAH contamination at the site was calculated. A multivariate statistical technique (principal component analysis or PCA) was used to provide an independent validation of the source allocation. The results of the source allocation provided a foundation for the site clean-up and remediation costs

  18. Exposure to dust-bound PAHs and associated carcinogenic risk in primitive and traditional cooking practices in Pakistan.

    Science.gov (United States)

    Kamal, Atif; Malik, Riffat Naseem; Martellini, Tania; Cincinelli, Alessandra

    2015-08-01

    The aim of this study was to determine the abundance and distribution of polycyclic aromatic hydrocarbons (PAHs) in dust samples collected from the selected professional cooking workplaces (WCs) and residential household cooking areas (WRs), where traditional and primitive cooking practices are still prevelent. Another aim of this study was to investigate the carcinogenic risk for Pakistani human exposure to dust-bound PAHs via the routes of inhalation, ingestion, and dermal contact. Generally, the concentration of individual congeners of PAHs in surface dust samples of WC sites was higher than those measured in WR sites (p < 0.05). The benzo(a)pyrene (B(a)P), a very high carcinogenic compound, was present in the dust samples from WC sites in the highest mean concentration (630 ng g(-1) dry weight (d.w.)). The BaP mean concentration in WC workplaces was almost eight times higher than the mean value found in WR exposure sites. Moreover, the average concentration of ∑PAHs, combustion origin PAHs (∑COMB) and sum total of 7-carcinogenic PAHs (∑7-carcinogens) were also significantly higher in WC dusts samples than that in WR workplaces. Principal component analysis (PCA) and diagnostic ratios suggested coal/wood combustion as major PAH emission sources in both exposure sites. The average incremental lifetime cancer risk (ILCR) suggested a moderate to potential high cancer risk for adults and children exposed to dust-bound PAHs in both exposure sites, in particular via both dermal and ingestion contact pathways.

  19. CHARACTERIZING SOIL/WATER SORPTION AND DESORPTION BEHAVIOR OF BTEX AND PAHS USING SELECTIVE SUPERCRITICAL FLUID EXTRACTION (SFE); TOPICAL

    International Nuclear Information System (INIS)

    Steve Hawthorne

    1998-01-01

    The first goal of the proposed study was to generate initial data to determine the ability of selective SFE behavior to mimic the soil/water sorption and desorption behavior of BTEX (benzene, toluene, and xylenes) and PAHs (polycyclic aromatic hydrocarbons).Samples generated by Professor Bill Rixey's column sorption studies (aged for 2 weeks to 8 months) and desorption studies (six weeks desorption of the aged soil columns with pure water) were extracted using sequentially-stronger SFE conditions to selectively remove different fractions of each BTEX and PAH component which range from loosely to tightly bound in the soil matrices. The selective SFE results parallel the sorption/desorption leaching behavior and mechanisms determined by Professor Rixey's investigations (under separate funding) using water desorption of soil columns previously aged with BTEX and PAHs. These results justify more intensive investigations of the use of selective SFE to mimic soil/water sorption and desorption of organic pollutants related to fossil fuels which will be performed under separate funding. The second goal of the study was to determine if selective SFE extraction behavior parallels the remediation behavior displayed by PAHs currently undergoing in-situ bioremediation at a manufactured gas plant (MGP) site. Based on soil analyses of several individual PAHs (as well as total PAHs) before remediation began, and after 147 days of remediation, selective SFE successfully mimicked remediation behavior. These results strongly support the use of selective SFE to predict remediation behavior of soils contaminated with PAHs, and are expected to provide a powerful and rapid analytical tool which will be useful for determining the remediation endpoints which are necessary for environmental protection. Based on the initial success found in the present study, additional investigations into the use of SFE for predicting and monitoring the remediation behavior of PAH-contaminated soils will be

  20. Kayser-Fleischer Rings

    Science.gov (United States)

    ... Support Contacts Lab Tracker/Copper Calculator Stories Programs & Research ... About Everything you need to know about Wilson Disease Kayser-Fleischer Rings Definition Kayser-Fleischer Ring: Clinical sign. Brownish-yellow ring visible around the corneo- ...

  1. ASSOCIATIVE RINGS SOLVED AS LIE RINGS

    Directory of Open Access Journals (Sweden)

    M. B. Smirnov

    2011-01-01

    Full Text Available The paper has proved that an associative ring which is solvable of a n- class as a Lie ring has a nilpotent ideal of the nilpotent class not more than 3×10n–2  and a corresponding quotient ring satisfies an identity [[x1, x2, [x3, x4

  2. Evaluation of PAH and PCB in soil

    International Nuclear Information System (INIS)

    Hein, D.; Delschen, T.

    1994-01-01

    The soil data obtained should be regarded as provisional, as there is still insufficient knowledge on the influence of accompanying substances such as organic solvents on the transfer behaviour and mobility of the soil pollutants under consideration. Moreover, the significance of metabolic processes in soils and plants is largely still unknown. There are no generally accepted standards for BCB and PAH analysis in soil and plants. The diversity in methods applied has led to widely disparate results. The data situation for PAH is so heterogeneous as to allow test results to be derived solely for benzo[a]pyrene. It will be a task for the future to clarify the extent to which other substances must be taken into account here, e.g., with respect to toxicity and availability. (orig.) [de

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

    Science.gov (United States)

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

    2015-01-01

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

  4. Seasonal variation, spatial distribution and source apportionment for polycyclic aromatic hydrocarbons (PAHs) at nineteen communities in Xi'an, China: The effects of suburban scattered emissions in winter.

    Science.gov (United States)

    Wang, Jingzhi; Cao, Junji; Dong, Zhibao; Guinot, Benjamin; Gao, Meiling; Huang, Rujin; Han, Yongming; Huang, Yu; Ho, Steven Sai Hang; Shen, Zhenxing

    2017-12-01

    Seasonal variation and spatial distribution of PM 2.5 bound polycyclic aromatic hydrocarbons (PAHs) were investigated at urban residential, commercial area, university, suburban region, and industry in Xi'an, during summer and winter time at 2013. Much higher levels of total PAHs were obtained in winter. Spatial distributions by kriging interpolations principle showed that relative high PAHs were detected in western Xi'an in both summer and winter, with decreasing trends in winter from the old city wall to the 2 nd -3rd ring road except for the suburban region and industry. Coefficients of diversity and statistics by SPSS method demonstrated that PAHs in suburban have significant differences (t winter and summer in urban, which different with the suburban. The coal combustion was the main source for PAHs in suburban region, which accounted for 46.6% in winter and sharp decreased to 19.2% in summer. Scattered emissions from uncontrolled coal combustion represent an important source of PAHs in suburban in winter and there were about 135 persons in Xi'an will suffer from lung cancer for lifetime exposure at winter levels. Further studies are needed to specify the effluence of the scattered emission in suburban to the city and to develop a strategy for controlling those emissions and lighten possible health effects. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Distribution of Gas Phase Polycyclic Aromatic Hydrocarbons (PAHs in Selected Indoor and Outdoor Air Samples of Malaysia: a Case Study in Serdang, Selangor and Bachang, Malacca

    Directory of Open Access Journals (Sweden)

    Haris Hafizal Abd Hamid

    2017-07-01

    Full Text Available Distribution of 10 polycyclic aromatic hydrocarbons (PAHs in the gas phase of air from selected indoor and outdoor areas of Selangor and Malacca, Malaysia has been investigated. A locally designed Semi Permeable Membrane Device (SPMD was applied for passive air sampling for 37 days at selected locations. Cleanup was carried out with Gas Purge - Micro Syringe Extraction (GP-MSE and the final analysis was using Gas Chromatography-Mass Spectrometry (GC-MS. In this study, 6 indoor and 12 outdoor locations were selected for air sampling. A total of 10 compounds of PAHs (Ʃ10PAHs were determined in the range of 0.218 ng/m3 - 1.692 ng/m3 and 0.378 ng/m3 - 1.492 ng/m3 in outdoor and indoor samples respectively. In the outdoor samples, locations such as near a petrol station and heavy traffic showed the maximum levels of Ʃ10PAHs, while rooftop samples showed the lowest Ʃ10PAHs. The distribution of gas phase Ʃ10PAHs was influenced by vehicular emission. Low molecular weight (LMW compounds (2-3 rings were dominant in all samples (>70% indicating that SPMD has successfully sampled the gas phase of the air.

  6. Biotransformation of the high-molecular weight polycyclic aromatic hydrocarbon (PAH) benzo[k]fluoranthene by Sphingobium sp. strain KK22 and identification of new products of non-alternant PAH biodegradation by liquid chromatography electrospray ionization tandem mass spectrometry

    Science.gov (United States)

    Maeda, Allyn H; Nishi, Shinro; Hatada, Yuji; Ozeki, Yasuhiro; Kanaly, Robert A

    2014-01-01

    A pathway for the biotransformation of the environmental pollutant and high-molecular weight polycyclic aromatic hydrocarbon (PAH) benzo[k]fluoranthene by a soil bacterium was constructed through analyses of results from liquid chromatography negative electrospray ionization tandem mass spectrometry (LC/ESI(–)-MS/MS). Exposure of Sphingobium sp. strain KK22 to benzo[k]fluoranthene resulted in transformation to four-, three-and two-aromatic ring products. The structurally similar four-and three-ring non-alternant PAHs fluoranthene and acenaphthylene were also biotransformed by strain KK22, and LC/ESI(–)-MS/MS analyses of these products confirmed the lower biotransformation pathway proposed for benzo[k]fluoranthene. In all, seven products from benzo[k]fluoranthene and seven products from fluoranthene were revealed and included previously unreported products from both PAHs. Benzo[k]fluoranthene biotransformation proceeded through ortho-cleavage of 8,9-dihydroxy-benzo[k]fluoranthene to 8-carboxyfluoranthenyl-9-propenic acid and 9-hydroxy-fluoranthene-8-carboxylic acid, and was followed by meta-cleavage to produce 3-(2-formylacenaphthylen-1-yl)-2-hydroxy-prop-2-enoic acid. The fluoranthene pathway converged with the benzo[k]fluoranthene pathway through detection of the three-ring product, 2-formylacenaphthylene-1-carboxylic acid. Production of key downstream metabolites, 1,8-naphthalic anhydride and 1-naphthoic acid from benzo[k]fluoranthene, fluoranthene and acenaphthylene biotransformations provided evidence for a common pathway by strain KK22 for all three PAHs through acenaphthoquinone. Quantitative analysis of benzo[k]fluoranthene biotransformation by strain KK22 confirmed biodegradation. This is the first pathway proposed for the biotransformation of benzo[k]fluoranthene by a bacterium. PMID:24325265

  7. Biotransformation of the high-molecular weight polycyclic aromatic hydrocarbon (PAH) benzo[k]fluoranthene by Sphingobium sp. strain KK22 and identification of new products of non-alternant PAH biodegradation by liquid chromatography electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Maeda, Allyn H; Nishi, Shinro; Hatada, Yuji; Ozeki, Yasuhiro; Kanaly, Robert A

    2014-03-01

    A pathway for the biotransformation of the environmental pollutant and high-molecular weight polycyclic aromatic hydrocarbon (PAH) benzo[k]fluoranthene by a soil bacterium was constructed through analyses of results from liquid chromatography negative electrospray ionization tandem mass spectrometry (LC/ESI(-)-MS/MS). Exposure of Sphingobium sp. strain KK22 to benzo[k]fluoranthene resulted in transformation to four-, three- and two-aromatic ring products. The structurally similar four- and three-ring non-alternant PAHs fluoranthene and acenaphthylene were also biotransformed by strain KK22, and LC/ESI(-)-MS/MS analyses of these products confirmed the lower biotransformation pathway proposed for benzo[k]fluoranthene. In all, seven products from benzo[k]fluoranthene and seven products from fluoranthene were revealed and included previously unreported products from both PAHs. Benzo[k]fluoranthene biotransformation proceeded through ortho-cleavage of 8,9-dihydroxy-benzo[k]fluoranthene to 8-carboxyfluoranthenyl-9-propenic acid and 9-hydroxy-fluoranthene-8-carboxylic acid, and was followed by meta-cleavage to produce 3-(2-formylacenaphthylen-1-yl)-2-hydroxy-prop-2-enoic acid. The fluoranthene pathway converged with the benzo[k]fluoranthene pathway through detection of the three-ring product, 2-formylacenaphthylene-1-carboxylic acid. Production of key downstream metabolites, 1,8-naphthalic anhydride and 1-naphthoic acid from benzo[k]fluoranthene, fluoranthene and acenaphthylene biotransformations provided evidence for a common pathway by strain KK22 for all three PAHs through acenaphthoquinone. Quantitative analysis of benzo[k]fluoranthene biotransformation by strain KK22 confirmed biodegradation. This is the first pathway proposed for the biotransformation of benzo[k]fluoranthene by a bacterium. © 2013 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

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

    Science.gov (United States)

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

    2018-04-01

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

  9. PAH exposure levels in mudpuppy (amphibian)

    Energy Technology Data Exchange (ETDEWEB)

    Trudeau, F; Maisonneuve, F [Environment Canada, Canadian Wildlife Service, Hull, PQ (Canada); Gendron, A D [Quebec Univ., Montreal, PQ (Canada); Bishop, C A [Environment Canada, Canada Centre for Inland Waters, Burlington, ON (Canada)

    1999-12-31

    The presence of PAHs in the environment is of great concern because of the mutagenic, teratogenic and carcinogenic properties of the metabolites produced in exposed organisms. In recent years, exposure of fish to PAHs was demonstrated by the detection of pyrene-type metabolites in bile, using synchronous fluorescence spectrometry (SFS), which offers a rapid screening tool to estimate recent exposure to PAHs. In this experiment, the SFS technique was applied to mudpuppy (Necturus maculosus), a benthic carnivorous salamander found in the lakes and rivers of northeastern America, susceptible to the chronic effects of contaminants accumulated through its diet and through its contact with the contaminated sediment. Samples were taken from a variety of locations (Akwesasne River, Batiscan River, in the St.-Lawrence River System, Des Prairies River and Quesnel Bay in the Ottawa River System, Wolfe Island, Long Point and the Detroit River in the Great Lakes Basin). Results of the examination showed that mud puppies collected from the Detroit River had, by far, the highest concentrations of biliary 1-hydroxy pyrene (798 ng/ml), compared to 84 ng/ml, or less, in other animals in the sample.

  10. PAH partitioning in a toxicity exposure chamber

    International Nuclear Information System (INIS)

    Sterling, M.C. Jr.; Autenrieth, R.L.; Bonner, J.S.; Page, C.A.; Fuller, C.B.; Ernest, A.N.S.

    2003-01-01

    The hypothesis that observed petroleum aromatic hydrocarbon (PAH) concentrations in an aqueous system are equal to the sum of the organic phase and the soluble phase molar concentrations was examined. Raoult's law was used to estimate the soluble phase molar concentrations. The organic phase concentrations were proportional to the PAH mole fraction in the oil. The experiment involved initially loading a batch laboratory mixing vessel with a scalable mixing energy at various oil layer thicknesses corresponding to oil surface loadings. The vessel was then agitated at a constant mean shear rate. Periodical total petroleum hydrocarbon (TPH) samples were taken in order to estimate the entrainment rate as a function of initial oil layer thickness. In-situ measurements of TPH concentrations were performed with the use of a laser scattering instrument while ex-situ measurements were effected using gravimetric analysis. Additional samples were analyzed for PAH concentration at a steady state TPH concentration using gas chromatograph/mass spectrometer (GC/MS) analysis. The results obtained were in agreement with a first order kinetic model (TPH concentrations increased over time). It was noted that in general, the first order rate constant and steady state concentration increased with increased oil loading and increased mean shear rates. There was good correlation between the measurements and the concentrations predicted using the hypothesized model. 8 refs., 3 tabs., 2 figs

  11. WR stars with ring nebulae

    International Nuclear Information System (INIS)

    Tutukov, A.

    1982-01-01

    It is shown that most of usually apparently single nitrogen WR stars with ring emission nebulae around them (WN + Neb) are a probable product of the evolution of a massive close binary with initial masses of components exceeding approximately 20 solar masses. (Auth.)

  12. Ring laser frequency biasing mechanism

    International Nuclear Information System (INIS)

    McClure, R.E.

    1975-01-01

    A ring laser cavity including a magnetically saturable member for differentially phase shifting the contradirectional waves propagating in the laser cavity, the phase shift being produced by the magneto-optic interaction occurring between the light waves and the magnetization in the cavity forming component as the light waves are reflected therefrom is described

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

    International Nuclear Information System (INIS)

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

    1986-02-01

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

  14. Seasonal Variations and Sources of Airborne Polycyclic Aromatic Hydrocarbons (PAHs in Chengdu, China

    Directory of Open Access Journals (Sweden)

    Ju Yang

    2018-02-01

    Full Text Available The concentrations of polycyclic aromatic hydrocarbons (PAHs in the air of Chengdu, a southwest city of China, were determined from March 2015 to February 2016. Here, two diagnostic ratios (DR were determined and a principal component analysis/multiple linear regression (PCA/MLR analysis was performed to identify the sources of PAHs during the four seasons. The gaseous and particle phase samples were analyzed separately. The sampled air had a gas-to particle ratio of 4.21, and between 18.7% and 31.3% of the total detected PAHs were found in the particulate phase. The total concentration of all 16-PAHs combined (gas + particles varied from 176.94 in summer to 458.95 ng·m−3 in winter, with a mean of 300.35 ± 176.6 ng·m−3. In the gas phase, phenanthrene(Phe was found at the highest concentrations in all four seasons, while benzo[b]fluoranthene(BbF and (in winter chrysene(Chr were the highest in the particle phase. The DR of Fluroanthene (Flua/(Flua + Pyrene (Pyr was higher in the gas phase than in the particle phase, while the Indeno[1,2,3-cd]pyrene(IcdP/(IcdP + Benzo[ghi]perylene (BghiP ratio was more variable in the gas than that in the particle phase. The main sources for both phases were a mixture of liquid fossil fuel combustion and the burning of biomass and coal, with clear seasonal variation. Principal Component Analysis/Multiple Linear Regression (PCA/MLR analysis identified the main PAH sources as coal burning (52% with motor vehicle exhaust and coke (48% in spring; coal (52%, coke (21%, and motor vehicle exhaust (27% in summer; coal (47%, vehicle exhaust (34%, and coke (19% in autumn; and coal (58% and vehicle exhaust (42% in winter.

  15. A CASE AGAINST SPINNING PAHS AS THE SOURCE OF THE ANOMALOUS MICROWAVE EMISSION

    Energy Technology Data Exchange (ETDEWEB)

    Hensley, Brandon S.; Draine, B. T. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Meisner, Aaron M., E-mail: brandon.s.hensley@jpl.nasa.gov [Berkeley Center for Cosmological Physics, Berkeley, CA 94720 (United States)

    2016-08-10

    We employ an all-sky map of the anomalous microwave emission (AME) produced by component separation of the microwave sky to study correlations between the AME and Galactic dust properties. We find that while the AME is highly correlated with all tracers of dust emission, the best predictor of the AME strength is the dust radiance. Fluctuations in the AME intensity per dust radiance are uncorrelated with fluctuations in the emission from polycyclic aromatic hydrocarbons (PAHs), casting doubt on the association between AME and PAHs. The PAH abundance is strongly correlated with the dust optical depth and dust radiance, consistent with PAH destruction in low density regions. We find that the AME intensity increases with increasing radiation field strength, at variance with predictions from the spinning dust hypothesis. Finally, the temperature dependence of the AME per dust radiance disfavors the interpretation of the AME as thermal emission. A reconsideration of other AME carriers, such as ultrasmall silicates, and other emission mechanisms, such as magnetic dipole emission, is warranted.

  16. Measurement of personal exposure to volatile organic compounds and particle associated PAH in three UK regions.

    Science.gov (United States)

    Saborit, Juana Mari Delgado; Aquilina, Noel J; Meddings, Claire; Baker, Stephen; Vardoulakis, Sotiris; Harrison, Roy M

    2009-06-15

    Personal exposures to 15 volatile organic compounds (VOC) and 16 polycyclic aromatic hydrocarbons (PAH) of 100 adult nonsmokers living in three UK areas, namely London, West Midlands, and rural South Wales, were measured using an actively pumped sampler carried around by the volunteers for 5/1 (VOC/PAH) consecutive 24-h periods, following their normal lifestyle. Results from personal exposure measurements categorized by geographical location, type of dwelling, and exposure to environmental tobacco smoke (ETS) are presented. The average personal exposure concentration to benzene, 1,3-butadiene, and benzo(a)pyrene representing the main carcinogenic components of the VOC and PAH mixture were 2.2 +/- 2.5 microg/m3, 0.4 +/- 0.7 microg/m3, and 0.3 +/- 0.7 ng/m3 respectively. The association of a number of generic factors with personal exposure concentrations was investigated, including first-line property, traffic, the presence of an integral garage, and ETS. Only living in houses with integral garages and being exposed to ETS were identified as unequivocal contributors to VOC personal exposure, while only ETS had a clear effect upon PAH personal exposures. The measurements of personal exposures were compared with health-based European and UK air quality guidelines, with some exceedences occurring. Activities contributing to high personal exposures included the use of a fireplace in the home, ETS exposure, DIY (i.e., construction and craftwork activities), and photocopying, among others.

  17. Characteristics of polycyclic aromatic hydrocarbon (PAH) emissions from a UH-1H helicopter engine and its impact on the ambient environment

    Science.gov (United States)

    Chen, Yu-Cheng; Lee, Wen-Jhy; Uang, Shi-Nian; Lee, Su-Hsing; Tsai, Perng-Jy

    The objective of this study is to characterize the emissions of polycyclic aromatic hydrocarbons (PAHs) from a UH-1H helicopter turboshaft engine and its impact on the ambient environment. Five power settings of the ground idle (GI), fly idle (FI), beed band check (BBC), inlet guide vane (IGV), and take off (TO) were selected and samples were collected from the exhaust by using an isokinetic sampling system. Twenty-two PAH compounds were analyzed by gas chromatograph (GC)/MS. We found the mean total PAH concentration in the exhaust of the UH-1H engine (843 μg m -3) is 1.05-51.7 times in magnitude higher than those of the heavy-duty diesel (HDD) engine, motor vehicle engine, and F101 aircraft engine. Two- and three-ringed PAHs account for 97.5% of total PAH emissions from the UH-1H engine. The mean total PAH and total BaP eq emission factors for the UH-1H engine (63.4 and 0.309 mg L -1·fuel) is 1.65-23.4 and 1.30-7.54 times in magnitude higher than those for the motor vehicle engine, HDD engine, and F101 aircraft engine. The total emission level of the single PAH compound, BaP, for the UH-1H engine (EL BaP) during one landing and take off (LTO) cycle (2.19 mg LTO -1) was higher than the European Commission standard (1.24 mg LTO -1) suggesting that appropriate measures should be taken to reduce PAH emissions from UH-1H engines in the future.

  18. Analysis of Polycyclic Aromatic Hydrocarbons (PAHs in soils using ultrasonic agitation, heater/mini condenser tube and gaseous chromatography

    Directory of Open Access Journals (Sweden)

    Jurandir Pereira Pinto

    2006-02-01

    Full Text Available The increase in the number of gas stations in Brazil made it also possible the increase in the risk of underground waters contamination due to fuel spill. The polycyclic aromatic hydrocarbons (PAHs are petroleum-derived components and constitute a group of organic pollutants which are persistent in the environment and have highly carcinogenic capacity. In this work it was developed a PAHs analysis methodology in soils for quantifying these components, using the gaseous chromatography technique, through the optimization and validation of the chromatographic as well as the extraction, concentration and purification conditions of the PAHs. A good resolution for the sixteen PAHs was obtained, with retention times ranging from 6.1 to 43.7 minutes. The tube-heater/mini condenser system used for the solvent evaporation also showed satisfactory recovery for the naphthalene (83% as well as the extraction method by ultrasonic agitation with dichloromethane, obtaining recoveries that ranged from 74 to 104%. The analysis method proved to be appropriate for the quantification of the 16 PAHs in the evaluation of the environmental contamination in gas stations.

  19. Plasma-ring, fast-opening switch

    International Nuclear Information System (INIS)

    Hartman, C.W.; Eddleman, J.; Hammer, J.H.

    1986-01-01

    The authors discuss a fast-opening switch concept based on magnetically confined plasma rings, PROS (for Plasma Ring Opening Switch). In PROS, the plasma ring, confined by Bθ /sub and B/poloidal /sub fields of a compact torus, provide a low mass, localized conduction path between coaxial electrodes. To operate the switch, driver current is passed across the electrodes through the ring, storing inductive energy in external inductance and between the electrodes on the driver side of the ring. The ring is accelerated away from the driver by the field of the driver current and passes over a load gap transferring the current to the load. The authors distinguish two configurations in PROS, straight PROS where the electrodes are coaxial cylinders, and cone PROS with conical electrodes. In straight PROS ring acceleration takes place during the inductive store period as in foil switches, but with the localized ring providing the current path. Increased performance is predicted for the cone PROS (see figure) which employs compression of the ring in the cone during the inductive store period. Here, the B/θ /sub field of the driver forces the ring towards the apex of the cone but the force is in near balance with the opposing component of the radial equilibrium force of the ring along the cone. As a result, the ring undergoes a slow, quasistatic compression limited only by resistive decay of the ring field. Slow compression allows inductive storage with low-power drivers (homopoloar, magneto cumulative generators, high C-low V capacitor banks, etc.). Near the apex of the cone, near peak compression, the ring is allowed to enter a straight coaxial section where, because of low-mass, it rapidly accelerates to high velocity and crosses the load gap

  20. PAH biomarkers in common eelpout (Zoarces viviparus) from Danish waters

    DEFF Research Database (Denmark)

    Tairova, Zhanna; Strand, Jakob; Chevalier, Julie

    2012-01-01

    Eelpouts (Zoarces viviparus) sampled at surveillance stations during the fall of 2007 and spring 2008 in different Danish coastal areas, were studied for biomarkers of polycyclic aromatic hydrocarbons (PAHs) exposure and effects. Two analytical techniques, synchronous fluorescence spectrometry (SFS......) and high-performance liquid chromatography with fluorescence detection (HPLC/F), were applied for detecting PAH metabolites in bile and urine. CYP1A activity, in this study regarded as potential biomarker of effect, was measured as 7-ethoxyresorufin-O-deethylase (EROD) activity in liver of eelpouts from...... different stations. Biliary PAH metabolite measurements were used for monitoring the environmental PAH load at the surveillance stations. There was found significant difference in biliary PAH metabolite content between sexes with male fish containing higher concentrations of PAH metabolites than females...

  1. Stirling engine piston ring

    Science.gov (United States)

    Howarth, Roy B.

    1983-01-01

    A piston ring design for a Stirling engine wherein the contact pressure between the piston and the cylinder is maintained at a uniform level, independent of engine conditions through a balancing of the pressure exerted upon the ring's surface and thereby allowing the contact pressure on the ring to be predetermined through the use of a preloaded expander ring.

  2. Alternative loop rings

    CERN Document Server

    Goodaire, EG; Polcino Milies, C

    1996-01-01

    For the past ten years, alternative loop rings have intrigued mathematicians from a wide cross-section of modern algebra. As a consequence, the theory of alternative loop rings has grown tremendously. One of the main developments is the complete characterization of loops which have an alternative but not associative, loop ring. Furthermore, there is a very close relationship between the algebraic structures of loop rings and of group rings over 2-groups. Another major topic of research is the study of the unit loop of the integral loop ring. Here the interaction between loop rings and group ri

  3. Barns kjemiske lekemiljø: Nivå og kilder til PAH i barnehagejord i Trondheim

    OpenAIRE

    Frøland, Stine Lindset

    2008-01-01

    Innholdet av 16 PAH-forbindelser og sumPAH(16) ble bestemt i 107 prøver av overflatejord fordelt på 10 barnehager i Trondheim. Sammenlignet med tidligere undersøkelser av PAH i Trondheim viser barnehagene det laveste innholdet av PAH. I barnehagene antydes det at vedfyring og veitrafikk er viktige kilder til den diffuse forurensningen av PAH.

  4. An experimental investigation into the formation of polycyclic-aromatic hydrocarbons (PAH) from pyrolysis of biomass materials

    Energy Technology Data Exchange (ETDEWEB)

    McGrath, T.; Sharma, R.; Hajaligol, M. [Philip Morris USA, Richmond, VA (United States). Research Center

    2001-10-09

    The formation of polycyclic-aromatic hydrocarbons (PAH) from the pyrolysis of cellulose, pectin and chlorogenic acid was studied. The primary product, mostly primary volatile tar, was exposed to a higher thermal severity i.e. high temperatures and long residence times. The reactor setup consisted of a quartz tube with two zones, zone I and II, each heated and controlled separately. Zone I was used to first pyrolyse the substrate at 300{degree}C to produce a low temperature tar (LTT) as well as to pyrolyse the product char at 600{degree}C to produce a high temperature tar (HTT). The LTT and HTT were then subjected to a high thermal severity in the second zone (zone II) where the temperature was varied between 700 and 850{degree}C. The residence time of the volatiles in zone II was varied between ca. 90 and 1400 ms (calculated at 800{degree}C). The results show that the yield of most PAHs increased with temperature, except in a few cases where the yield of two- and three-ring PAHs exhibited a maximum. PAHs yields also generally increased as the residence time was increased from 90 to 1400 ms at 800{degree}C. 19 refs., 9 figs., 2 tabs.

  5. Interaction of Vortex Ring with Cutting Plate

    Science.gov (United States)

    Musta, Mustafa

    2015-11-01

    The interaction of a vortex ring impinging on a thin cutting plate was made experimentally using Volumetric 3-component Velocitmetry (v3v) technique. The vortex rings were generated with piston-cylinder vortex ring generator using piston stroke-to-diameter ratios and Re at 2-3 and 1500 - 3000, respectively. The cutting of vortex rings below center line leads to the formation of secondary vortices on each side of the plate which is look like two vortex rings, and a third vortex ring propagates further downstream in the direction of the initial vortex ring, which is previously showed by flow visualization study of Weigand (1993) and called ``trifurcation''. Trifurcation is very sensitive to the initial Reynolds number and the position of the plate with respect to the vortex ring generator pipe. The present work seeks more detailed investigation on the trifurcation using V3V technique. Conditions for the formation of trifurcation is analyzed and compared with Weigand (1993). The formed secondary vortex rings and the propagation of initial vortex ring in the downstream of the plate are analyzed by calculating their circulation, energy and trajectories.

  6. Grafted cellulose for PAHs removal present in industrial discharge waters

    Science.gov (United States)

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

    2014-05-01

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

  7. PAH in Some Brands of Tea and Coffee

    DEFF Research Database (Denmark)

    Duedahl-Olesen, Lene; Navaratnam, Marin Arosha; Jewula, J.

    2015-01-01

    The presence of 25 polycyclic aromatic hydrocarbons (PAHs) in tea and coffee were investigated with focus on four PAHs (PAH4), classified by the European Food Safety Authority (EFSA) as suitable indicators; benz[a]anthracene (BaA), chrysene (CHR), benzo[b]fluoranthene (BbF) and benzo[a]pyrene (Ba......P). PAH4 from samples of 18 brands of tea leaves and 13 brands of coffee were extracted by pressurized liquid extraction (PLE) followed by highly automated clean up steps for gel permeation chromatography (SX-3) and solid phase extraction (500mg silica). GC-MS were applied for detection of PAH4. The limit...... of detection (LOD) ranged from 0.1–0.3 μg/kg with recoveries from 94–106% for PAH4. Concentrations of PAH4 followed the pattern of the total sum of 25 PAHs with higher concentrations with a maximum of 115 μg/kg in tea leaves compared to 5.1 μg/kg in coffee. The highest PAH4 levels were found in black tea...

  8. SOR-ring failure

    International Nuclear Information System (INIS)

    Kitamura, Hideo

    1981-01-01

    It was in the autumn of 1976 that the SOR-ring (synchrotron radiation storage ring) has commenced the regular operation. Since then, the period when the operation was interrupted due to the failures of SOR-ring itself is in total about 8 weeks. Failures and accidents have occurred most in the vacuum system. Those failure experiences are described on the vacuum, electromagnet, radio-frequency acceleration and beam transport systems with their interrupted periods. The eleven failures in the vacuum system have been reported, such as bellows breakage in a heating-evacuating period, leakage from the bellows of straight-through valves (made in U.S.A. and Japan), and leakage from the joint flange of the vacuum system. The longest interruption was 5 weeks due to the failure of a domestically manufactured straight-through valve. The failures of the electromagnet system involve the breakage in a cooling water system, short circuit of a winding in the Q magnet power transformer, blow of a fuse protecting the deflection magnet power source by the current less than the rating, and others. The failures of the RF acceleration system include the breakage of an output electronic tube the breakage of a cavity ceramic, RF voltage fluctuation due to the contact deterioration at a cavity electrode, and the failure of grid bias power source. It is necessary to select the highly reliable components for the vacuum system because the vacuum system failures require longer time for recovery, and very likely to induce secondary and tertiary failures. (Wakatsuki, Y.)

  9. Bioavailability of polycyclic aromatic hydrocarbons (PAHs) to short-neck clam (Paphia undulata) from sediment matrices in mudflat ecosystem of the west coast of Peninsular Malaysia.

    Science.gov (United States)

    Keshavarzifard, Mehrzad; Zakaria, Mohamad Pauzi; Hwai, Tan Shau

    2017-06-01

    The bioaccumulation and bioavailability of polycyclic aromatic hydrocarbons (PAHs) were characterized in sediment and Paphia undulata (short-neck clam) from six mudflat areas in the west coasts of Peninsular Malaysia. The concentrations of total PAHs varied from 357.1 to 6257.1 and 179.9 ± 7.6 to 1657.5 ± 53.9 ng g -1 dry weight in sediment and short-neck clam samples, respectively. PAHs can be classified as moderate to very high level of pollution in sediments and moderate to high level of pollution in short-neck clams. The diagnostic ratios of individual PAHs and principal component analysis indicate both petrogenic and pyrogenic sources with significant dominance of pyrogenic source. The first PAHs biota-sediment accumulation factors and relative biota-sediment accumulation factors data for short-neck clam were obtained in this study, indicating a preferential accumulation of lower molecular weight PAHs. Evaluation of PAH levels in sediments and short-neck clams indicates that short-neck clam could be introduced as a good biomonitor in mudflats. The results also demonstrated that under environmental conditions, the sedimentary load of hydrocarbons appears to be one of the factors controlling their bioavailability to biota.

  10. Alkyl PAH in crude oil cause chronic toxicity to early life stages of fish. Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    Hodson, P.V.; Khan, C.W.; Saravanabhavan, G.; Clarke, L.; Brown, R.S. [Queen' s Univ., Kingston, ON (Canada). School of Environmental Studies; Hollebone, B.; Wang, Z. [Environment Canada, Ottawa, ON (Canada). ; Short, J. [National Oceanic and Atmospheric Administration, Juneau, AK (United States). Auke Bay Lab; Lee, K.; King, T. [Fisheries and Oceans Canada, Dartmouth, NS (Canada). Centre for Offshore Oil and Gas Environmental Research

    2007-07-01

    In order to mitigate the risk to fisheries following an offshore oil spill, it is necessary to know the components of crude oil that are toxic. Chronic exposure of early life stages of fish to crude oil causes Blue Sac Disease, a syndrome characterized by induction of the cytochrome P450 (CYP1A) enzyme. In this study, effects-driven fractionation of Alaska North Slope Crude was used to identify the classes of compounds that cause CYP1A induction in juvenile rainbow trout and chronic toxicity to developing stages of Japanese medaka. Four fractions of compounds were created by low temperature vacuum distillation. This separated the constituents of oil according to their volatility within defined temperature ranges. The fractions were separated according to their boiling points. With a temperature range of 287-481 degrees C, fraction F3 was the only fraction as toxic as whole oil and induced CYPP1A enzymes of fish. Fractions containing specific classes of alkyl PAH were also collected. For all separations, the performance of the method was evaluated by the extent to which PAH were separated from aliphatics, resins and waxes, as well as by the quantitative recovery of mass in fractions and subfractions. The induction of CYP1A enzymes showed that PAH was present in all fractions that were highly toxic, but the toxicity tests indicated that not all fractions containing PAH were toxic. This research provided a scientific basis for comparing the risks of different crude oils based on chemical analyses that show the different proportions or amounts of PAH present. The results indicate which compounds of concern should be used to determine the extent and success of oil spill remediation, and provide a biological interpretation of chemical fingerprinting used to discriminate the sources of oil pollution. 15 refs., 1 tab.

  11. Alkyl PAH in crude oil cause chronic toxicity to early life stages of fish

    Energy Technology Data Exchange (ETDEWEB)

    Hodson, P.V.; Khan, C.W.; Saravanabhavan, G.; Clarke, L.; Brown, R.S. [Queen' s Univ., Kingston, ON (Canada). School of Environmental Studies; Hollebone, B.; Wang, Z. [Environment Canada, Ottawa, ON (Canada). ; Short, J. [National Oceanic and Atmospheric Administration, Juneau, AK (United States). Auke Bay Lab; Lee, K.; King, T. [Fisheries and Oceans Canada, Dartmouth, NS (Canada). Centre for Offshore Oil and Gas Environmental Research

    2007-07-01

    In order to mitigate the risk to fisheries following an offshore oil spill, it is necessary to know the components of crude oil that are toxic. Chronic exposure of early life stages of fish to crude oil causes Blue Sac Disease, a syndrome characterized by induction of the cytochrome P450 (CYP1A) enzyme. In this study, effects-driven fractionation of Alaska North Slope Crude was used to identify the classes of compounds that cause CYP1A induction in juvenile rainbow trout and chronic toxicity to developing stages of Japanese medaka. Four fractions of compounds were created by low temperature vacuum distillation. This separated the constituents of oil according to their volatility within defined temperature ranges. The fractions were separated according to their boiling points. With a temperature range of 287-481 degrees C, fraction F3 was the only fraction as toxic as whole oil and induced CYPP1A enzymes of fish. Fractions containing specific classes of alkyl PAH were also collected. For all separations, the performance of the method was evaluated by the extent to which PAH were separated from aliphatics, resins and waxes, as well as by the quantitative recovery of mass in fractions and subfractions. The induction of CYP1A enzymes showed that PAH was present in all fractions that were highly toxic, but the toxicity tests indicated that not all fractions containing PAH were toxic. This research provided a scientific basis for comparing the risks of different crude oils based on chemical analyses that show the different proportions or amounts of PAH present. The results indicate which compounds of concern should be used to determine the extent and success of oil spill remediation, and provide a biological interpretation of chemical fingerprinting used to discriminate the sources of oil pollution. 15 refs., 1 tab.

  12. Analytical Evaluation to Determine Selected PAHs by HPLC in a Type 2 Fuel; Evaluacion Analitica de 4 Metodos de Determinacion de PAHs medianteHPLC en un Fuel de Tipo II

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Alonso, S.; Perez Pastor, R. M.; Sevillano Castano, M. L.; Escolano Segovia, O.; Garcia Frutos, F. J.

    2009-05-21

    An evaluation of analytical parameters to determine selected PAHs in a fuel oil type II by HPLC coupled to fluorescence and diode detectors is presented. The study was focused on four conventional treatments of these kinds of oil samples and the main objective was giving a measure of confidence level of PAH results in the fuel oil. This study was performed in the frame of the project Assessment of natural attenuation of PAHs in agricultural soil contaminated with fuel from an accidental spill (Spanish National Plain I+D+I, CTM2007-64537). This paper is presented as follows: Analysis of reference material 1582 (NIST) by using the four kinds of sample treatments of interest. Application of variance analysis to compare results obtained from type II fuel by using each sample treatment and chromatographic detector. Finally, a statistic calculation was performed to measure uncertainty components in chromatographic analysis. (Author)

  13. Uncertainty Evaluation and Influence of Gran Size to Determine PAHs in a Contaminated Soil; Influencia del Tamano de Particula de un Suelo Contaminado en las Incertidumbres Asociadas al Metodo de Determinacion de PAHs

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Alonso, S.; Perez Pastor, R. M.; Escolano Segoviano, O.; Garcia Frutos, F. J.

    2007-07-20

    An evaluation of uncertainty associated to PAH determination in a contaminated soil is presented. The work was focused to measure the influence of grain size on concentration deviations and give a measure of result confidence of PAHs in the gasworks contaminated soil. This study was performed in the frame of the project 'Assessment of natural remediation technologies for PAHs in contaminated soils'(Spanish Plan Nacional I+D+i, CTM 2004-05832-CO2-01). This paper is presented as follows: A brief introduction which describes the main uncertainty contributions associated to chromatographic analysis. Afterwards, a statistic calculation was performed to measure each uncertainty component. Finally, a global uncertainty was calculated and the influence of grain size and distribution of compounds according to volatility was evaluated. (Author) 10 refs.

  14. Global time trends in PAH emissions from motor vehicles

    Science.gov (United States)

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

    2011-04-01

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

  15. Cloud deposition of PAHs at Mount Lushan in southern China.

    Science.gov (United States)

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

    2015-09-01

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

  16. A comparative study to evaluate natural attenuation, mycoaugmentation, phytoremediation, and microbial-assisted phytoremediation strategies for the bioremediation of an aged PAH-polluted soil.

    Science.gov (United States)

    García-Sánchez, Mercedes; Košnář, Zdeněk; Mercl, Filip; Aranda, Elisabet; Tlustoš, Pavel

    2018-01-01

    Biological treatments are considered an environmentally option to clean-up polluted soil with polycyclic aromatic hydrocarbons (PAHs). A pot experiment was conducted to comparatively evaluate four different strategies, including natural attenuation (NA), mycoaugmentation (M) by using Crucibulum leave, phytoremediation (P) using maize plants, and microbial-assisted phytoremediation (MAP) for the bioremediation of an aged PAH-polluted soil at 180 days. The P treatment had higher affinity degrading 2-3 and 4 ring compounds than NA and M treatments, respectively. However, M and P treatments were more efficient in regards to naphthalene, indeno[l,2,3-c,d]pyrene and benzo[g,h,i]perylene degradation respect to NA. However, 4, 5-6 rings undergo a strong decline during the microbe-assisted phytoremediation, being the treatment which determined the highest rates of PAHs degradation. Sixteen PAH compounds, except fluorene and dibenzo[a,h]anthracene, were found in maize roots, whereas the naphthalene, phenanthrene, anthracene, fluoranthene, and pyrene were accumulated in the shoots, in both P and MAP treatments. However, higher PAH content in maize biomass was achieved during the MAP treatment respect to P treatment. The bioconversion and translocation factors were less than 1, indicating that phystabilization/phytodegradation processes occurred rather than phytoextraction. The microbial biomass, activity and ergosterol content were significantly boosted in the MAP treatment respect to the other treatments at 180 days. Ours results demonstrated that maize-C. laeve association was the most profitable technique for the treatment of an aged PAH-polluted soil when compared to other bioremediation approaches. Copyright © 2017 Elsevier Inc. All rights reserved.

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

    Science.gov (United States)

    Boersma, Christiaan

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

  18. Chemometric techniques in distribution, characterisation and source apportionment of polycyclic aromatic hydrocarbons (PAHS) in aquaculture sediments in Malaysia.

    Science.gov (United States)

    Retnam, Ananthy; Zakaria, Mohamad Pauzi; Juahir, Hafizan; Aris, Ahmad Zaharin; Zali, Munirah Abdul; Kasim, Mohd Fadhil

    2013-04-15

    This study investigated polycyclic aromatic hydrocarbons (PAHs) pollution in surface sediments within aquaculture areas in Peninsular Malaysia using chemometric techniques, forensics and univariate methods. The samples were analysed using soxhlet extraction, silica gel column clean-up and gas chromatography mass spectrometry. The total PAH concentrations ranged from 20 to 1841 ng/g with a mean of 363 ng/g dw. The application of chemometric techniques enabled clustering and discrimination of the aquaculture sediments into four groups according to the contamination levels. A combination of chemometric and molecular indices was used to identify the sources of PAHs, which could be attributed to vehicle emissions, oil combustion and biomass combustion. Source apportionment using absolute principle component scores-multiple linear regression showed that the main sources of PAHs are vehicle emissions 54%, oil 37% and biomass combustion 9%. Land-based pollution from vehicle emissions is the predominant contributor of PAHs in the aquaculture sediments of Peninsular Malaysia. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Seasonal variation of the particle size distribution of n-alkanes and polycyclic aromatic hydrocarbons (PAHs) in urban aerosol of Guangzhou, China.

    Science.gov (United States)

    Tang, X L; Bi, X H; Sheng, G Y; Tan, J H; Fu, J M

    2006-06-01

    Seasonal aerosol samples have been collected by Andersen Hi-Vol pumping system equipped with a five stage cascade impactor and a backup filter (size range: 10-7.2 microm, 7.2-3.0 microm, 3.0-1.5 microm, 1.5-0.95 microm, 0.95-0.49 microm, gas chromatography and PAHs were measured using gas chromatography/mass spectrometry analysis. The bimodal log-normal distributions of n-alkanes and semi-volatile PAHs were found, while for non-volatile PAHs that was unimodal, so much as the mode of semi-volatile PAHs was similar with that of the particles. The n-alkanes and PAHs were preferably associated with fine particles. C (max) (carbon number maximum) (C(22)-C(26)), CPI (carbon preference index) (1.12-1.21), U/R (unresolved to resolved components ratio) (7.42-10.7), wax% (0.9-3.12%) and the diagnostic ratios for PAHs revealed that vehicular emission was the major source of these organic compounds during the study periods, while the contribution of epicuticular waxes emitted by terrestrial plants was minor. CPI(2) (values for petrogenic hydrocarbons), CPI(3) (values for biogenic n-alkanes) and wax% revealed that the natural preferentially accumulated in the larger aerosol while the anthropogenic in the smaller. In addition, the different MMDs (mass median diameters) for n-alkanes and PAHs were observed in different seasons. The MMDs for n-alkanes and PAHs were higher in autumn/winter than those in spring/summer. The seasonal effect was related to the hydrocarbon content in the individual particulate fractions, showing a preferential association of n-alkanes and PAHs with larger particles in the autumn/winter season.

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

    Science.gov (United States)

    Ciemniak, Artur; Witczak, Agata

    2010-01-01

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

  1. Rapid persulfate oxidation predicts PAH bioavailability in soils and sediments

    NARCIS (Netherlands)

    Cuypers, M.P.; Grotenhuis, J.T.C.; Joziasse, J.; Rulkens, W.H.

    2000-01-01

    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

  2. Effect of Smoking on Polycyclic Aromatic Hydrocarbons (PAHS ...

    African Journals Online (AJOL)

    ADOWIE PERE

    Manage. Vol. 22 (2) 293 - 297. February 2018. Full-text Available Online at ... aromatic hydrocarbons (PAHs) were studied in raw and smoked samples of catfish (Clarias ... inferred that the smoking process generally increased the mean total PAH levels in the fish .... with 5 g of anhydrous sodium sulphate in a laboratory.

  3. Polyaromatic hydrocarbons (PAHs) levels from two industrial zones ...

    African Journals Online (AJOL)

    Polyaromatic hydrocarbons (PAHs) levels from two industrial zones (Sihwa and Banwal) located in An-san city ... PROMOTING ACCESS TO AFRICAN RESEARCH ... method (HVAS-Sibata) was employed to collect airborne PAHs in both the particulate and gas phases. ... EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT

  4. Urinary 1-hydroxypyrene, a PAH biomarker in foundry workers

    DEFF Research Database (Denmark)

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

    1996-01-01

    Exposure to PAH in foundry workers has been studied by urinary 1-hydroxypyrene (HPU) levels, quantitatively measured by reversed phase HPLC. Seventy male foundry workers and 68 matched controls were investigated. Polycyclic aromatic hydrocarbon (PAH) exposure was defined by 17 breathing zone hygi...

  5. PAH loss during bioremediation of manufactured gas plant site soils

    Energy Technology Data Exchange (ETDEWEB)

    Erickson, D C [and others

    1993-01-01

    Laboratory studies using soil samples from a former gas works site showed that PAH in the soil were present in a form resistant to biodegradation, whereas added naphthalene and phenanthrene were quickly degraded. The PAH already present were not extractable into water, and were not toxic to bacteria.

  6. Cloud deposition of PAHs at Mount Lushan in southern China

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ruixia [School of Environmental Science and Engineering, Shandong University, Jinan, 250100 (China); Wang, Yan, E-mail: wangyan405@gmail.com [School of Environmental Science and Engineering, Shandong University, Jinan, 250100 (China); Li, Hongli, E-mail: lihongli1225@163.com [Environmental Monitoring Central Station of Shandong Province, Jinan, 250101 (China); Yang, Minmin; Sun, Lei [School of Environmental Science and Engineering, Shandong University, Jinan, 250100 (China); Wang, Tao [Department of Civil and Structural Engineering, The Hong Kong Polytechnic University, Hong Kong (China); Wang, Wenxing [Environment Research Institute, Shandong University, Jinan, 250100 (China)

    2015-09-01

    Cloud water samples were collected from Mount Lushan, a high alpine area of southern China, and analyzed using GC–MS to investigate the concentration levels, seasonal variations, particle-dissolved phase partitioning, ecological risk of PAHs and its relationship to the atmosphere and rainwater. The average concentration of total (dissolved + particle) PAHs in cloud water was 819.90 ng/L, which ranged from 2.30 ng/L for DbA to 295.38 ng/L for PhA. PhA (33.11%) contributed the most individual PAHs, followed by Flu (28.24%). Distinct seasonal variations in the total PAHs measured in this research had a higher concentration during the spring and a lower concentration during the summer. When cloud events occurred, the concentration of the atmospheric PAHs of the two phases decreased. The contribution from the gaseous phase of total PAHs in the air to the dissolved phase in cloud water was up to 60.43%, but the particulate phase in the air only contributed 39.57% to the total scavenging. The contribution of total PAHs from the atmosphere to clouds is higher in the gaseous phase than in the particulate phase. A comparative study of the concentrations of cloud water and the closest rain water revealed that the PAH concentration in rainwater was 1.80 times less than that of cloud water and that the dominant individual compounds in cloud water and rainwater were PhA and Flu. A total of 81.27% of the PAHs in cloud samples and 72.21% of the PAHs in rain samples remained in the dissolved phase. Ecological risk assessment indicated that PAHs in cloud water in spring and summer caused a certain degree of ecosystem risk and the mean ecosystem risk in spring was higher than that in summer. - Highlights: • The site is in the high pollution emission area, having many sources of PAHs around. • Mount Lushan is a unique site for cloud chemistry monitoring. • Atmospheric PAHs mostly deposited and transferred into cloud water. • Special case showed PAHs are more concentrated in

  7. Cloud deposition of PAHs at Mount Lushan in southern China

    International Nuclear Information System (INIS)

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

    2015-01-01

    Cloud water samples were collected from Mount Lushan, a high alpine area of southern China, and analyzed using GC–MS to investigate the concentration levels, seasonal variations, particle-dissolved phase partitioning, ecological risk of PAHs and its relationship to the atmosphere and rainwater. The average concentration of total (dissolved + particle) PAHs in cloud water was 819.90 ng/L, which ranged from 2.30 ng/L for DbA to 295.38 ng/L for PhA. PhA (33.11%) contributed the most individual PAHs, followed by Flu (28.24%). Distinct seasonal variations in the total PAHs measured in this research had a higher concentration during the spring and a lower concentration during the summer. When cloud events occurred, the concentration of the atmospheric PAHs of the two phases decreased. The contribution from the gaseous phase of total PAHs in the air to the dissolved phase in cloud water was up to 60.43%, but the particulate phase in the air only contributed 39.57% to the total scavenging. The contribution of total PAHs from the atmosphere to clouds is higher in the gaseous phase than in the particulate phase. A comparative study of the concentrations of cloud water and the closest rain water revealed that the PAH concentration in rainwater was 1.80 times less than that of cloud water and that the dominant individual compounds in cloud water and rainwater were PhA and Flu. A total of 81.27% of the PAHs in cloud samples and 72.21% of the PAHs in rain samples remained in the dissolved phase. Ecological risk assessment indicated that PAHs in cloud water in spring and summer caused a certain degree of ecosystem risk and the mean ecosystem risk in spring was higher than that in summer. - Highlights: • The site is in the high pollution emission area, having many sources of PAHs around. • Mount Lushan is a unique site for cloud chemistry monitoring. • Atmospheric PAHs mostly deposited and transferred into cloud water. • Special case showed PAHs are more concentrated in

  8. Analysis of PAHs Associated with Particulate Matter PM2.5 in Two Places at the City of Cuernavaca, Morelos, México

    Directory of Open Access Journals (Sweden)

    Hugo Saldarriaga-Noreña

    2015-08-01

    Full Text Available This study was carried out between January and February 2013, at two sites in the city of Cuernavaca, México, using low-volume equipment. Fifteen Polycyclic aromatic hydrocarbons (PAHs, were identified by gas chromatography coupled with mass spectrometry. The total average concentration observed for PAHs was 24.0 ng·m−3, with the high molecular weight compounds being the most abundant. The estimated equivalent concentration for Benzo (a P (BaPE was 4.05 ng·m−3. Diagnostic ratios together with the principal components analysis (PCA allowed for establishing coal burning and vehicle emissions as being the main sources of these compounds in the area. The PAHs used to calculate this index account for 51% of the 15 PAHs identified, which probably involves a risk to the exposed population.

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

    International Nuclear Information System (INIS)

    Zhang, Yong; Kwok, Sun

    2015-01-01

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

  10. Kandungan Senyawa Polisiklik Aromatik Hidrokarbon (PAH di Teluk Jakarta (Polycyclic Aromatic Compounds Hydrocarbons (PAH Content in Jakarta Bay

    Directory of Open Access Journals (Sweden)

    Fasmi Ahmad

    2013-07-01

    Full Text Available Perairan Teluk Jakarta menerima limbah yang berasal dari darat maupun perairan itu sendiri. Salah satu limbah tersebut adalah senyawa organik Polisiklik Aromatik Hidrokarbon (PAH yang merupakan senyawa organik bersifat toksik terhadap biota laut. Penelitian dilakukan untuk mengetahui kandungan PAH air laut dan sedimen dalam kaitannya dengan kehidupan biota laut serta mengetahui sumber senyawa tersebut. Pengukuran dilakukan bulan Maret 2011. Contoh air laut diambil dengan water sampler dan contoh sedimen dengan grab pada 15 stasiun. Kadar PAH dianalisa dengan Gas Chromatography-Flame Ionization Detector. Hasil penelitian menunjukkan kadar PAH air laut di Teluk Jakarta Bagian Barat > Bagian Tengah > Bagian Timur. Kandungan PAH di Teluk Jakarta Bagian Barat berkisar 201,57-474,68 ppb dengan total PAH 1404,68 ppb, di Bagian Tengah 104,61-337,07 ppb dengan total 825,63 ppb, dan di Bagian Timur 112,91-370,79 ppb dengan total 806,73 ppb. Data ini menunjukkan Teluk Jakarta Bagian Barat lebih banyak menerima masukan limbah yang mengandung PAH. Sedangkan Kadar PAH sedimen di Teluk Jakarta Bagian Timur > Bagian Tengah > Bagian Barat. Kadar PAH di Teluk Jakarta Bagian Barat berkisar 1,92-64,241 ppm dengan total 107,931 ppm, di Bagian Tengah 16,14-77,71 ppm dengan total 170,61 ppm, dan di Bagian Timur 8,72-115,39 ppm dengan total 252,25 ppm. Data ini menunjukkan sedimen di Teluk Jakarta Bagian Timur lebih banyak mengakumulasi limbah yang mengandung PAH. Sumber PAH dalam air laut dan sedimen ini berasal dari berbagai sumber yakni pembakaran bahan organik, pembakaran minyak bumi, dan tumpahan minyak. Kadar PAH dalam air laut di Teluk Jakarta ini telah melebihi Nilai Ambang Batas yang ditetapkan oleh KMNLH untuk biota laut, dan Nilai Ambang Batas untuk sedimen yang ditetapkan oleh Handbook for Sediment Quality Assessment. Kata kunci: Teluk Jakarta, Polisiklik Aromatik Hidrokarbon, PAH, polusi Jakarta Bay receives various kinds of waste both from land and waters

  11. Enhanced bioremediation of PAH contaminated soils from coal processing sites

    International Nuclear Information System (INIS)

    Joshi, M.M.; Lee, S.

    1995-01-01

    The polycyclic aromatic hydrocarbons (PAH) are a potential hazard to health due to their carcinogenic, mutagenic nature and acute toxicity and there is an imminent need for remediation of PAH contaminated soils abounding the several coke oven and town gas sites. Aerobic biological degradation of PAHs is an innovative technology and has shown high decontamination efficiencies, complete mineralization of contaminants, and is environmentally safe. The present study investigates the remediation of PAH contaminated soils achieved using Acinetobacter species and fungal strain Phanerochaete Chrysosporium. The soil used for the experiments was an industrially contaminated soil obtained from Alberta Research Council (ARC) primary cleanup facility, Alberta, Canada. Soil characterization was done using High Performance Liquid Chromatography (HPLC) to qualitatively and quantitatively determine the contaminants in the soil. Artificially contaminated soil was also used for some experiments. All the experiments were conducted under completely mixed conditions with suitable oxygen and nutrient amendments. The removal efficiency obtained for various PAHs using the two microorganisms was compared

  12. Electrochemical Oxidation of PAHs in Water from Harbor Sediment Purification

    DEFF Research Database (Denmark)

    Muff, Jens; Søgaard, Erik Gydesen

    2010-01-01

    generated oxidant solution with a free chlorine concentration of 2 gL-1. Both strategies resulted in a successful degradation of 5 PAHs to fulfil the discharge limit on 0.010 µgL-1. The intermixing-with-oxidant approach can also be applied as a method to address the actual sediment matrix....... of the discharge water addressing primarily polycyclic aromatic hydrocarbons (PAHs). PAHs are by-products of incomplete combustion of organic materials with recalcitrant and strong mutagenic/carcinogenic properties, due to their benzene analogue structures. PAHs are hydrophobic compounds and their persistence...... evidence for the importance of the indirect oxidation mechanism in the degradation of the PAHs. The proof-of-concept study was conducted both by a direct treatment approach and an intermixing-with-oxidant approach, where the contaminated water was intermixed in different ratios with an electrochemically...

  13. Central regions of LIRGs: rings, hidden starbursts, Supernovae and star clusters

    International Nuclear Information System (INIS)

    Väisänen, Petri; Randriamanakoto, Zara; Escala, Andres; Kankare, Erkki; Mattila, Seppo; Reunanen, Juha; Kotilainen, Jari; Rajpaul, Vinesh; Ryder, Stuart; Zijlstra, Albert

    2012-01-01

    We study star formation (SF) in very active environments, in luminous IR galaxies, which are often interacting. A variety of phenomena are detected, such as central starbursts, circumnuclear SF, obscured SNe tracing the history of recent SF, massive super star clusters, and sites of strong off-nuclear SF. All of these can be ultimately used to define the sequence of triggering and propagation of star-formation and interplay with nuclear activity in the lives of gas rich galaxy interactions and mergers. In this paper we present analysis of high-spatial resolution integral field spectroscopy of central regions of two interacting LIRGs. We detect a nuclear 3.3 μm PAH ring around the core of NGC 1614 with thermal-IR IFU observations. The ring's characteristics and relation to the strong star-forming ring detected in recombination lines are presented, as well as a scenario of an outward expanding starburst likely initiated with a (minor) companion detected within a tidal feature. We then present NIR IFU observations of IRAS 19115-2124, aka the Bird, which is an intriguing triple encounter. The third component is a minor one, but, nevertheless, is the source of 3/4 of the SFR of the whole system. Gas inflows and outflows are detected in their nuclei locations. Finally, we briefly report on our on-going NIR adaptive optics imaging survey of several dozen LIRGs. We have detected highly obscured core-collapse SNe in the central kpc, and discuss the statistics of 'missing SNe' due to dust extinction. We are also determining the characteristics of hundreds of super star clusters in and around the core regions of LIRGs, as a function of host-galaxy properties.

  14. Rings in drugs.

    Science.gov (United States)

    Taylor, Richard D; MacCoss, Malcolm; Lawson, Alastair D G

    2014-07-24

    We have analyzed the rings, ring systems, and frameworks in drugs listed in the FDA Orange Book to understand the frequency, timelines, molecular property space, and the application of these rings in different therapeutic areas and target classes. This analysis shows that there are only 351 ring systems and 1197 frameworks in drugs that came onto the market before 2013. Furthermore, on average six new ring systems enter drug space each year and approximately 28% of new drugs contain a new ring system. Moreover, it is very unusual for a drug to contain more than one new ring system and the majority of the most frequently used ring systems (83%) were first used in drugs developed prior to 1983. These observations give insight into the chemical novelty of drugs and potentially efficient ways to assess compound libraries and develop compounds from hit identification to lead optimization and beyond.

  15. Birth Control Ring

    Science.gov (United States)

    ... Health Food & Fitness Diseases & Conditions Infections Drugs & Alcohol School & Jobs Sports Expert Answers (Q&A) Staying Safe Videos for Educators Search English Español Birth Control Ring KidsHealth / For Teens / Birth Control Ring What's ...

  16. Comparative developmental toxicity of environmentally relevant oxygenated PAHs

    International Nuclear Information System (INIS)

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

    2013-01-01

    Oxygenated polycyclic aromatic hydrocarbons (OPAHs) are byproducts of combustion and photo-oxidation of parent PAHs. OPAHs are widely present in the environment and pose an unknown hazard to human health. The developing zebrafish was used to evaluate a structurally diverse set of 38 OPAHs for malformation induction, gene expression changes and mitochondrial function. Zebrafish embryos were exposed from 6 to 120 h post fertilization (hpf) to a dilution series of 38 different OPAHs and evaluated for 22 developmental endpoints. AHR activation was determined via CYP1A immunohistochemistry. Phenanthrenequinone (9,10-PHEQ), 1,9-benz-10-anthrone (BEZO), xanthone (XAN), benz(a)anthracene-7,12-dione (7,12-B[a]AQ), and 9,10-anthraquinone (9,10-ANTQ) were evaluated for transcriptional responses at 48 hpf, prior to the onset of malformations. qRT-PCR was conducted for a number of oxidative stress genes, including the glutathione transferase(gst), glutathione peroxidase(gpx), and superoxide dismutase(sod) families. Bioenergetics was assayed to measure in vivo oxidative stress and mitochondrial function in 26 hpf embryos exposed to OPAHs. Hierarchical clustering of the structure-activity outcomes indicated that the most toxic of the OPAHs contained adjacent diones on 6-carbon moieties or terminal, para-diones on multi-ring structures. 5-carbon moieties with adjacent diones were among the least toxic OPAHs while the toxicity of multi-ring structures with more centralized para-diones varied considerably. 9,10-PHEQ, BEZO, 7,12-B[a]AQ, and XAN exposures increased expression of several oxidative stress related genes and decreased oxygen consumption rate (OCR), a measurement of mitochondrial respiration. Comprehensive in vivo characterization of 38 structurally diverse OPAHs indicated differential AHR dependency and a prominent role for oxidative stress in the toxicity mechanisms. - Highlights: • OPAHs are byproducts of combustion present in the environment. • OPAHs pose a largely

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

    Science.gov (United States)

    2015-01-01

    Passive sampling devices were used to measure air vapor and water dissolved phase concentrations of 33 polycyclic aromatic hydrocarbons (PAHs) and 22 oxygenated PAHs (OPAHs) at four Gulf of Mexico coastal sites prior to, during, and after shoreline oiling from the Deepwater Horizon oil spill (DWH). Measurements were taken at each site over a 13 month period, and flux across the water–air boundary was determined. This is the first report of vapor phase and flux of both PAHs and OPAHs during the DWH. Vapor phase sum PAH and OPAH concentrations ranged between 1 and 24 ng/m3 and 0.3 and 27 ng/m3, respectively. PAH and OPAH concentrations in air exhibited different spatial and temporal trends than in water, and air–water flux of 13 individual PAHs 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/m2/day. Acenaphthene was the PAH with the highest observed volatilization rate of 6800 ng/m2/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

  18. Polycyclic aromatic hydrocarbon (PAH) and oxygenated PAH (OPAH) air-water exchange during the deepwater horizon oil spill.

    Science.gov (United States)

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

    2015-01-06

    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.

  19. Groups, rings, modules

    CERN Document Server

    Auslander, Maurice

    2014-01-01

    This classic monograph is geared toward advanced undergraduates and graduate students. The treatment presupposes some familiarity with sets, groups, rings, and vector spaces. The four-part approach begins with examinations of sets and maps, monoids and groups, categories, and rings. The second part explores unique factorization domains, general module theory, semisimple rings and modules, and Artinian rings. Part three's topics include localization and tensor products, principal ideal domains, and applications of fundamental theorem. The fourth and final part covers algebraic field extensions

  20. Measurement of polynuclear aromatic hydrocarbons (PAHs) in epiphytic lichens and from PM 2.5 filters for receptor modeling in the Alberta Oil Sands Region (Invited)

    Science.gov (United States)

    Studabaker, W. B.; Jayanty, J.; Raymer, J. H.; Krupa, S.

    2013-12-01

    contribution of low ring number PAHs to total PAHs increased with increasing distance. Total PAHs correlated strongly (R2 > 0.80, p particulate matter transport mechanisms, whereas PAHs in samples collected from remote areas reflect more of the vapor phase transport mechanisms.

  1. Influence of Air Pollution and Soil Contamination on the Contents of Polycyclic Aromatic Hydrocarbons (PAHs in Vegetables Grown in Urban Gardens of Sao Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Luís F. Amato-Lourenco

    2017-11-01

    Full Text Available Urban community gardens (UCGs have become prevalent worldwide and play a significant role in strengthening the sustainability of urban food systems. Although UCGs provide multiple benefits to society, the extent to which vegetables grown in them are contaminated by chemical compounds derived from airborne fallout or soil contamination is unclear. We evaluated the influence of both air pollution and the contamination of garden soil beds on the contents of 16 PAHs in the edible tissues of spinach and collard green. The PAH contents were quantified using gas chromatography-mass spectrometry (GC-MS-EI. The concentrations of PAHs in both the vegetables grown in the vessels and in the soil of the UCGs were <0.1 μg kg−1. The total concentrations of the 16 priority PAHs in the soil beds ranged from 132.94 to 410.50 μg kg−1. These levels were lower than those that have been reported from other urban areas. Principal Component Analysis resulted in two components indicating that traffic-derived emissions are the main sources of PAHs in the soil. The first component represented the compounds with higher molecular weights and had a moderate loading for the fine fraction of the soil (clay (0.63. The second component showed a high loading for silt (0.97, including those PAHs with lower molecular weights. Our data show that spinach and collard greens do not accumulate significant PAH concentrations on their leaves over 45-day periods, whether they are raised in controlled soil or in local beds.

  2. Seasonal variation, spatial distribution and source apportionment for polycyclic aromatic hydrocarbons (PAHs) at nineteen communities in Xi'an, China: The effects of suburban scattered emissions in winter

    International Nuclear Information System (INIS)

    Wang, Jingzhi; Cao, Junji; Dong, Zhibao; Guinot, Benjamin; Gao, Meiling; Huang, Rujin; Han, Yongming; Huang, Yu

    2017-01-01

    Seasonal variation and spatial distribution of PM 2.5 bound polycyclic aromatic hydrocarbons (PAHs) were investigated at urban residential, commercial area, university, suburban region, and industry in Xi'an, during summer and winter time at 2013. Much higher levels of total PAHs were obtained in winter. Spatial distributions by kriging interpolations principle showed that relative high PAHs were detected in western Xi'an in both summer and winter, with decreasing trends in winter from the old city wall to the 2 nd -3rd ring road except for the suburban region and industry. Coefficients of diversity and statistics by SPSS method demonstrated that PAHs in suburban have significant differences (t < 0.05) with those in urban residential in both seasons. The positive Matrix Factorization (PMF) modeling indicated that biomass burning (31.1%) and vehicle emissions (35.9%) were main sources for PAHs in winter and summer in urban, which different with the suburban. The coal combustion was the main source for PAHs in suburban region, which accounted for 46.6% in winter and sharp decreased to 19.2% in summer. Scattered emissions from uncontrolled coal combustion represent an important source of PAHs in suburban in winter and there were about 135 persons in Xi'an will suffer from lung cancer for lifetime exposure at winter levels. Further studies are needed to specify the effluence of the scattered emission in suburban to the city and to develop a strategy for controlling those emissions and lighten possible health effects. - Highlights: • PM 2.5 bound PAHs were investigated in nineteen communities of Xi'an at 2013. • High amount of uncontrolled coal combustion were happened in suburban at winter. • About 135 persons in Xi'an will suffer from lung cancer for exposure at winter. - The high contribution of coal combustion for PAHs in suburban region demonstrated the high amount of scattered emissions in winter.

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

    Science.gov (United States)

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

    2012-01-01

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

  4. Decontamination of soils containing PAHs by electroremediation: a review.

    Science.gov (United States)

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

    2010-05-15

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

  5. PAH diagnostic ratios for the identification of pollution emission sources

    International Nuclear Information System (INIS)

    Tobiszewski, Marek; Namieśnik, Jacek

    2012-01-01

    Polycyclic aromatic hydrocarbon (PAH) diagnostic ratios have recently come into common use as a tool for identifying and assessing pollution emission sources. Some diagnostic ratios are based on parent PAHs, others on the proportions of alkyl-substituted to non-substituted molecules. The ratios are applicable to PAHs determined in different environmental media: air (gas + particle phase), water, sediment, soil, as well as biomonitor organisms such as leaves or coniferous needles, and mussels. These ratios distinguish PAH pollution originating from petroleum products, petroleum combustion and biomass or coal burning. The compounds involved in each ratio have the same molar mass, so it is assumed they have similar physicochemical properties. Numerous studies show that diagnostic ratios change in value to different extents during phase transfers and environmental degradation. The paper reviews applications of diagnostic ratios, comments on their use and specifies their limitations. - Highlights: ► PAH diagnostic ratios may identify pollution coming from petroleum spills, fuel combustion and coal or biomass burning. ► They are sensitive to changes during PAHs environmental fate processes. ► Some diagnostic ratios are of limited value due to fast photodegradation of one of the compounds. - The paper reviews PAH diagnostic ratios that are applied to identify pollution emission originating from petroleum products, fuel combustion or coal and biomass burning.

  6. PAH emissions from coal combustion and waste incineration.

    Science.gov (United States)

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

    2016-11-15

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

  7. PAH exposure through soil ingestion: Combining digestion models and bioassays

    Energy Technology Data Exchange (ETDEWEB)

    Wiele, T.R. van de; Verstraete, W. [Ghent University (BE).Laboratory Microbial Ecology and Technology (LabMET); Siciliano, S.D. [University of Saskatchewan (Canada). Department of Soil Science

    2003-07-01

    Exposure to environmental contaminants through soil ingestion is an important issue in current health risk assessment. Polycyclic aromatic hydrocarbons (PAH) or their metabolites pose risks to humans due to their toxic, mutagenic, carcinogenic or even (anti)estrogenic properties. PAH mobilization from a soil matrix (49.1{+-}1.5 mg PAH/kg DW) was assessed using a Simulator of the Human Intestinal Microbial Ecosystem (SHIME). PAH GC-MS analysis was performed on the pellet and supernatant of SHIME digests and gave 101, 92, 89 and 97% recovery for water, stomach, duodenal and colon digests, respectively. PAH release was highest for the water extract (0.51%) and the stomach digestion (0.44%). Lower mobilized fractions in the duodenum (0.13%) and colon (0.30%) digests could be attributed to PAH complexation with bile salts, dissolved organic matter or colon microbiota. The digestion model provides us with relevant information to what extent soil bound PAHs are mobilized in the gastrointestinal tract and thus reach the gut wall, prior to absorption. (orig.)

  8. Alignment for new Subaru ring

    International Nuclear Information System (INIS)

    Zhang, Ch.; Matsui, S.; Hashimoto, S.

    1999-01-01

    The New SUBARU is a synchrotron light source being constructed at the SPring-8 site. The main facility is a 1.5 GeV electron storage ring that provides light beam in the region from VUV to soft X-ray using SPring-8's 1 GeV linac as an injector. The ring, with a circumference of about 119 meters, is composed of six bending cells. Each bending cell has two normal dipoles of 34 degree and one inverse dipole of -8 degree. The ring has six straight sections: two very long straight sections for a 11-m long undulator and an optical klystron, four short straight sections for a 2.3-m undulator, a super-conducting wiggler, rf cavity and injection, etc. The magnets of the storage ring are composed of 12 dipoles (BMs), 6 invert dipoles (BIs), 56 quadrupoles and 44 sextupoles, etc. For the magnet alignment, positions of the dipoles (the BMs and BIs) are determined by network survey method. The multipoles, which are mounted on girders between the dipoles, are aligned with a laser-CCD camera system. This article presents the methodology used to position the different components and particularly to assure the precise alignment of the multipoles. (authors)

  9. The levels of polycyclic aromatic hydrocarbons (PAHs) in human milk and exposure risk to breastfed infants in petrochemical industrialized Lanzhou Valley, Northwest China.

    Science.gov (United States)

    Wang, Li; Liu, Aiping; Zhao, Yuan; Mu, Xi; Huang, Tao; Gao, Hong; Ma, Jianmin

    2018-04-03

    We investigated in this paper the presence of PAHs in human milk from lactating women residing in Lanzhou, a petrochemical industrialized valley city in Northwest China. The PAH concentration levels in human milk samples from 98 healthy women were determined by gas chromatography/mass spectrometry (GC/MS). The associations between the lifestyle factors and the PAHs levels of human milk were analyzed. Moreover, we applied principal component analysis (PCA) method to gain a better insight into the similarities or dissimilarities of the human milk PAH loads and different pathways of source exposure. In addition, the exposure risks of breastfed infants due to PAH ingestion via breast milk were assessed and the relative breast-feeding risk to the total intake dose of infants was addressed. The results showed that the average fat-normalized human milk ∑ 15 PAHs concentrations for the lactating women residing in four districts of Lanzhou, namely, Xigu, Anning, Qilihe, and Chengguan were 320.40, 270.36, 374.04, and 259.84 ng/g of fat, respectively. The ∑ 15 PAHs of human milk from the lactating women of Qilihe District exhibited the highest concentration level, while the concentration level for women from Xigu District is the second highest for the observed human milk ∑ 15 PAHs. And the corresponding BaPeq concentrations for women in Xigu, Anning, Qilihe, and Chengguan districts were 58.29, 47.95, 65.13, and 45.60 ng/g of fat, respectively. A significant correlation was only found between human milk and living district environment (p milk PAHs, we confirmed that consuming barbecue food could elevate PAHs levels in human milk: the barbecue intake frequency caused 10% fluctuation of ∑ 15 PAHs concentration between high frequency and low frequency group in our study. Furthermore, the exposure to second-hand smoke can also increase the ∑ 15 PAHs levels in human milk by 4 to 11% here. Ingestion doses of PAHs by infants (19.37-77.75 ng kg -1  day -1 ) were much

  10. Atmospheric concentrations, sources and gas-particle partitioning of PAHs in Beijing after the 29th Olympic Games

    Energy Technology Data Exchange (ETDEWEB)

    Ma Wanli [International Joint Research Center for Persistent Toxic Substances (IJRC-PTS), State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Sun Dezhi [International Joint Research Center for Persistent Toxic Substances (IJRC-PTS), State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083 (China); Shen Weiguo [College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083 (China); Yang Meng [IJRC-PTS, Dalian Maritime University, Dalian (China); Qi Hong; Liu Liyan; Shen Jimin [International Joint Research Center for Persistent Toxic Substances (IJRC-PTS), State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Li Yifan, E-mail: ijrc_pts_paper@yahoo.com [International Joint Research Center for Persistent Toxic Substances (IJRC-PTS), State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Science and Technology Branch, Environment Canada, Toronto, Ontario M3H5T4 (Canada)

    2011-07-15

    A comprehensive sampling campaign was carried out to study atmospheric concentration of polycyclic aromatic hydrocarbons (PAHs) in Beijing and to evaluate the effectiveness of source control strategies in reducing PAHs pollution after the 29th Olympic Games. The sub-cooled liquid vapor pressure (logP{sub L}{sup o})-based model and octanol-air partition coefficient (K{sub oa})-based model were applied based on each seasonal dateset. Regression analysis among log K{sub P}, logP{sub L}{sup o} and log K{sub oa} exhibited high significant correlations for four seasons. Source factors were identified by principle component analysis and contributions were further estimated by multiple linear regression. Pyrogenic sources and coke oven emission were identified as major sources for both the non-heating and heating seasons. As compared with literatures, the mean PAH concentrations before and after the 29th Olympic Games were reduced by more than 60%, indicating that the source control measures were effective for reducing PAHs pollution in Beijing. - Highlights: > This is the first comprehensive study of PAHs in atmosphere after the 29th Olympics in Beijing, China. > The air quality before and after 29th Olympics has attracted much attention worldwide. > The study was helpful for other countries to understand how the Olympics affected PAHs emissions. > The study would act as a case study to know the effects that big events can impose on the host cities. - The source control measures implemented before and during the 29th Olympic Games were effective for reducing the emissions of air pollutants in Beijing.

  11. Integral Ring Carbon-Carbon Piston

    Science.gov (United States)

    Northam, G. Burton (Inventor)

    1999-01-01

    An improved structure for a reciprocating internal combustion engine or compressor piston fabricate from carbon-carbon composite materials is disclosed. An integral ring carbon-carbon composite piston, disclosed herein, reduces the need for piston rings and for small clearances by providing a small flexible, integral component around the piston that allows for variation in clearance due to manufacturing tolerances, distortion due to pressure and thermal loads, and variations in thermal expansion differences between the piston and cylinder liner.

  12. PAH analysis in Leipzig allotment soils; Untersuchungen zum Gefaehrdungspotential polycyclischer aromatischer Kohlenwasserstoffe (PAK) in Leipziger Kleingartenboeden

    Energy Technology Data Exchange (ETDEWEB)

    Bittrich, R.; Butze, B.; Mueller, S.; Prawalsky, R.; Stoye, H. [Umwelt-Consult e.V., Leipzig (Germany)

    2000-09-01

    Soils in 29 allotments were analyzed systematically with a view to the following aspects: Concentration ratios of the 16 components analyzed. Occurrence and classification of so-called PAH patterns. Interdependences between PAH patterns and soil features. PAH concentrations and soil-immanent buffer characteristics (humus concentration, pH, clay concentration, sesquioxide concentrations, exchange capacity). [German] Die vorliegende Arbeit konzentriert sich auf die Untersuchung der PAK-Belastung kleingaertnerisch genutzter Boeden. Die hier vorgestellten Ergebnisse resultieren aus Probjekten von Umwelt-Consult e.V. aus den Jahren 1995 bis 1997 im Auftrag der Stadt Leipzig und dem unter fachlicher Begleitung des Referates Geochemie der Abt. Boden/Geochemie vom LfUG gefoerderten Forschungsvorhaben 'Untersuchungen zum Gefaehrdungspotential polycyclischer aromatischer Kohlenwasserstoffe (PAK) in Boeden der Stadt Leipzig'. Hierbei wurden systematisch Boeden in 29 Kleingartenanlagen untersucht. Folgende Fragestellungen sollten beantwortet werden: Stehen die PAK-Konzentrationen der 16 analysierten Einzelkomponenten in bestimmten Groessenverhaeltnissen zueinander? Sind sogenannte PAK-Muster zu erkennen und lassen sich diese klassifizieren? Welche Beziehungen gibt es zwischen PAK-Mustern und Bodenmerkmalen? Korrespondieren die PAK-Konzentrationen (Gesamt-PAK, Einzelkomponenten) im Boden und deren bodenhorizont-bezogene Abfolge mit der Auspraegung bodenimmanenter Puffermerkmale (Humusgehalt, pH-Wert, Tongehalt, Gehalt an Sesquioxiden, Austauschkapazitaet)? (orig.)

  13. Carbonyl compounds and PAH emissions from CNG heavy-duty engine

    International Nuclear Information System (INIS)

    Gambino, M.; Cericola, R.; Corbo, P.; Iannaccone, S.

    1993-01-01

    Previous works carried out in Istituto Motori laboratories have shown that natural gas is a suitable fuel for general means of transportation. This is because of its favorable effects on engine performance and pollutant emissions. The natural gas fueled engine provided the same performance as the diesel engine, met R49 emission standards, and showed very low smoke levels. On the other hand, it is well known that internal combustion engines emit some components that are harmful for human health, such as carbonyl compounds and polycyclic aromatic hydrocarbons (PAH). This paper shows the results of carbonyl compounds and PAH emissions analysis for a heavy-duty Otto cycle engine fueled with natural gas. The engine was tested using the R49 cycle that is used to measure the regulated emissions. The test analysis has been compared with an analysis of a diesel engine, tested under the same conditions. Total PAH emissions from the CNG engine were about three orders of magnitude lower than from the diesel engine. Formaldehyde emission from the CNG engine was about ten times as much as from the diesel engine, while emissions of other carbonyl compounds were comparable

  14. Spatial Variability of PAHs and Microbial Community Structure in Surrounding Surficial Soil of Coal-Fired Power Plants in Xuzhou, China.

    Science.gov (United States)

    Ma, Jing; Zhang, Wangyuan; Chen, Yi; Zhang, Shaoliang; Feng, Qiyan; Hou, Huping; Chen, Fu

    2016-09-02

    This work investigated the spatial profile and source analysis of polycyclic aromatic hydrocarbons (PAHs) in soil that surrounds coal-fired power plants in Xuzhou, China. High-throughput sequencing was employed to investigate the composition and structure of soil bacterial communities. The total concentration of 15 PAHs in the surface soils ranged from 164.87 to 3494.81 μg/kg dry weight. The spatial profile of PAHs was site-specific with a concentration of 1400.09-3494.81 μg/kg in Yaozhuang. Based on the qualitative and principal component analysis results, coal burning and vehicle emission were found to be the main sources of PAHs in the surface soils. The phylogenetic analysis revealed differences in bacterial community compositions among different sampling sites. Proteobacteria was the most abundant phylum, while Acidobacteria was the second most abundant. The orders of Campylobacterales, Desulfobacterales and Hydrogenophilales had the most significant differences in relative abundance among the sampling sites. The redundancy analysis revealed that the differences in bacterial communities could be explained by the organic matter content. They could also be explicated by the acenaphthene concentration with longer arrows. Furthermore, OTUs of Proteobacteria phylum plotted around particular samples were confirmed to have a different composition of Proteobacteria phylum among the sample sites. Evaluating the relationship between soil PAHs concentration and bacterial community composition may provide useful information for the remediation of PAH contaminated sites.

  15. Spatial Variability of PAHs and Microbial Community Structure in Surrounding Surficial Soil of Coal-Fired Power Plants in Xuzhou, China

    Directory of Open Access Journals (Sweden)

    Jing Ma

    2016-09-01

    Full Text Available This work investigated the spatial profile and source analysis of polycyclic aromatic hydrocarbons (PAHs in soil that surrounds coal-fired power plants in Xuzhou, China. High-throughput sequencing was employed to investigate the composition and structure of soil bacterial communities. The total concentration of 15 PAHs in the surface soils ranged from 164.87 to 3494.81 μg/kg dry weight. The spatial profile of PAHs was site-specific with a concentration of 1400.09–3494.81 μg/kg in Yaozhuang. Based on the qualitative and principal component analysis results, coal burning and vehicle emission were found to be the main sources of PAHs in the surface soils. The phylogenetic analysis revealed differences in bacterial community compositions among different sampling sites. Proteobacteria was the most abundant phylum, while Acidobacteria was the second most abundant. The orders of Campylobacterales, Desulfobacterales and Hydrogenophilales had the most significant differences in relative abundance among the sampling sites. The redundancy analysis revealed that the differences in bacterial communities could be explained by the organic matter content. They could also be explicated by the acenaphthene concentration with longer arrows. Furthermore, OTUs of Proteobacteria phylum plotted around particular samples were confirmed to have a different composition of Proteobacteria phylum among the sample sites. Evaluating the relationship between soil PAHs concentration and bacterial community composition may provide useful information for the remediation of PAH contaminated sites.

  16. Biodegradation of PAHs by fungi in contaminated-soil containing ...

    African Journals Online (AJOL)

    PAH) benzo(a)anthracene, benzo(a) fluoranthene, benzo(a) pyrene, chrysene and phenanthrene in a soil that was sterilized and inoculated with the nonligninolytic fungi, Fusarium flocciferum and Trichoderma spp. and the ligninolytic fungi, ...

  17. Polycyclic Aromatic Hydrocarbons (PAHs) Content in Cattle Hides ...

    African Journals Online (AJOL)

    ADOWIE PERE

    ABSTRACT: Scrap rubber tyre is used as fuel for singeing animal carcasses in third world countries despite the fact that it can .... test method and the quantification of the PAH analytes using ... waste, SW-846 methods) with some modifications.

  18. PAHs sensitivity of picophytoplankton populations in the Red Sea

    KAUST Repository

    Kottuparambil, Sreejith; Agusti, Susana

    2018-01-01

    are higher than those reported for picophytoplankton from other oligotrophic marine waters and exceed by far the natural levels of PAHs in many oceans. Our findings reveal a possible adaptation of picophytoplankton populations to oil-related contaminants

  19. Ambient water quality criteria for polycyclic aromatic hydrocarbons (PAHs)

    Energy Technology Data Exchange (ETDEWEB)

    Nagpal, N.K.

    1993-08-13

    Ambient water quality criteria are established for polyaromatic hydrocarbons (PAH) in British Columbia. Major sources of PAH in the atmosphere and aquatic environments include, for the atmosphere, forest and prairie fires, agricultural burning, refuse burning, enclosed incineration, and heating and power, and for the aquatic environment, petroleum spillage, atmospheric deposition, wastewaters, surface land runoff, and biosynthesis. Details are presented of PAH and their characteristics, forms and transformations, occurrence in the environment, drinking water concerns, aquatic life concerns, wildlife concerns, livestock water supply concerns, and irrigation concerns. Application of criteria for aquatic life is discussed including phototoxic vs long term criteria, assessment of existing water quality, setting water quality objectives, and PAH levels in smoked fish. 221 refs., 5 figs., 30 tabs.

  20. Token Ring Project

    Directory of Open Access Journals (Sweden)

    Adela Ionescu

    2007-01-01

    Full Text Available Ring topology is a simple configuration used to connect processes that communicate among themselves. A number of network standards such as token ring, token bus, and FDDI are based on the ring connectivity. This article will develop an implementation of a ring of processes that communicate among themselves via pipe links. The processes are nodes in the ring. Each process reads from its standard input and writes in its standard output. N-1 process redirects the its standard output to a standard input of the process through a pipe. When the ring-structure is designed, the project can be extended to simulate networks or to implement algorithms for mutual exclusion

  1. Health risk assessment and source study of PAHs from roadside soil dust of a heavy mining area in India.

    Science.gov (United States)

    Tarafdar, Abhrajyoti; Sinha, Alok

    2018-02-26

    The total concentrations of 13 detected polycyclic aromatic hydrocarbons (PAHs) in different traffic soil samples of Dhanbad heavy mining area, India, were between 8.256 and 12.562 µg/g and were dominated by four ring PAHs (44%). Diagnostic ratio study revealed that fossil fuel burning and vehicular pollution are the most prominent sources of the PAHs in roadside soil even at a heavy coal mining area. The 90th percentiles cancer risks determined by probabilistic health risk assessment (Monte Carlo simulations) for both the age groups (children and adults) were above tolerable limit (>1.00E-06) according to USEPA. The simulated mean cancer risk was 1.854E-05 for children and 1.823E-05 for adults. For different exposure pathways, dermal contact was observed to be the major pathway with an exposure load of 74% for children and 85% for adults. Sensitivity analysis demonstrated relative skin adherence factor for soil (AF) is the most influential parameter of the simulation, followed by exposure duration (ED).

  2. Exploring the potential of fungi isolated from PAH-polluted soil as a source of xenobiotics-degrading fungi.

    Science.gov (United States)

    Godoy, Patricia; Reina, Rocío; Calderón, Andrea; Wittich, Regina-Michaela; García-Romera, Inmaculada; Aranda, Elisabet

    2016-10-01

    The aim of this study was to find polycyclic aromatic hydrocarbon (PAH)-degrading fungi adapted to polluted environments for further application in bioremediation processes. In this study, a total of 23 fungal species were isolated from a historically pyrogenic PAH-polluted soil in Spain and taxonomically identified. The dominant groups in these samples were the ones associated with fungi belonging to the Ascomycota phylum and two isolates belonging to the Mucoromycotina subphylum and Basiodiomycota phylum. We tested their ability to convert the three-ring PAH anthracene in a 42-day time course and analysed their ability to secrete extracellular oxidoreductase enzymes. Among the 23 fungal species screened, 12 were able to oxidize anthracene, leading to the formation of 9,10-anthraquinone as the main metabolite, a less toxic one than the parent compound. The complete removal of anthracene was achieved by three fungal species. In the case of Scopulariopsis brevicaulis, extracellular enzyme independent degradation of the initial 100 μM anthracene occurred, whilst in the case of the ligninolytic fungus Fomes (Basidiomycota), the same result was obtained with extracellular enzyme-dependent transformation. The yield of accumulated 9,10-anthraquinone was 80 and 91 %, respectively, and Fomes sp. could slowly deplete it from the growth medium when offered alone. These results are indicative for the effectiveness of these fungi for pollutant removal. Graphical abstract ᅟ.

  3. Roles of abiotic losses, microbes, plant roots, and root exudates on phytoremediation of PAHs in a barren soil.

    Science.gov (United States)

    Sun, Tian-Ran; Cang, Long; Wang, Quan-Ying; Zhou, Dong-Mei; Cheng, Jie-Min; Xu, Hui

    2010-04-15

    Phytoremediation is an emerging technology for the remediation of polycyclic aromatic hydrocarbons (PAHs). In this study, pot experiments were conducted to evaluate the efficacy of phytoremediation of phenanthrene and pyrene in a typical low organic matter soil (3.75 g kg(-1)), and the contribution proportions of abiotic losses, microbes, plant roots, and root exudates were ascertained during the PAHs dissipation. The results indicated that contribution of abiotic losses from this soil was high both for phenanthrene (83.4%) and pyrene (57.2%). The contributions of root-exudates-enhanced biodegradation of phenanthrene (15.5%) and pyrene (21.3%) were higher than those of indigenous microbial degradation. The role of root exudates on dissipation of phenanthrene and pyrene was evident in this experiment. By the way, with the increasing of ring numbers in PAHs structures, the root-exudates-enhanced degradation became more and more important. BIOLOG-ECO plate analysis indicated that microbial community structure of the soil receiving root exudates had changed. The removal efficiency and substrate utilization rate in the treatment with plant roots were lower than the treatment only with root exudates, which suggested that possible competition between roots and microbes for nutrients had occurred in a low organic matter soil. 2009. Published by Elsevier B.V.

  4. Radioactive gold ring dermatitis

    International Nuclear Information System (INIS)

    Miller, R.A.; Aldrich, J.E.

    1990-01-01

    A superficial squamous cell carcinoma developed in a woman who wore a radioactive gold ring for more than 30 years. Only part of the ring was radioactive. Radiation dose measurements indicated that the dose to basal skin layer was 2.4 Gy (240 rad) per week. If it is assumed that the woman continually wore her wedding ring for 37 years since purchase, she would have received a maximum dose of approximately 4600 Gy

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

    Directory of Open Access Journals (Sweden)

    Evin Danisman Bruschweiler

    2012-10-01

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

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

    Science.gov (United States)

    Zhang, Guizhai; Diao, Youjiang

    2018-06-01

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

  7. Physics of quantum rings

    International Nuclear Information System (INIS)

    Fomin, Vladimir M.

    2014-01-01

    Presents the new class of materials of quantum rings. Provides an elemental basis for low-cost high-performance devices promising for electronics, optoelectronics, spintronics and quantum information processing. Explains the physical properties of quantum rings to cover a gap in scientific literature. Presents the application of most advanced nanoengineering and nanocharacterization techniques. This book deals with a new class of materials, quantum rings. Innovative recent advances in experimental and theoretical physics of quantum rings are based on the most advanced state-of-the-art fabrication and characterization techniques as well as theoretical methods. The experimental efforts allow to obtain a new class of semiconductor quantum rings formed by capping self-organized quantum dots grown by molecular beam epitaxy. Novel optical and magnetic properties of quantum rings are associated with non-trivial topologies at the nanoscale. An adequate characterization of quantum rings is possible on the basis of modern characterization methods of nanostructures, such as Scanning Tunneling Microscopy. A high level of complexity is demonstrated to be needed for a dedicated theoretical model to adequately represent the specific features of quantum rings. The findings presented in this book contribute to develop low-cost high-performance electronic, spintronic, optoelectronic and information processing devices based on quantum rings.

  8. Reductions of PAH and Soot by Center Air Injection

    Directory of Open Access Journals (Sweden)

    Kazuhiro Yamamoto

    2014-07-01

    Full Text Available In this study, to reduce the amount of pollutant PAH and soot in the flame, we examined the burner system equipped with a center air injection. For this purpose, by using PAH-LIF and soot LII, we evaluated relative PAH and soot amounts in both the triple port burner and the conventional co-axial burner (double port burner to discuss effects of center air injection on the formation of PAH and soot. The fuel was propane. In the triple port burner, two different blue flames are observed near the burner rim, followed by bright luminous flames with soot. The flame length is longer when the fuel flow velocity is increased. On the other hand, the flame length is shorter with an increase in internal air flow velocity. As for PAH and soot, these amounts of the triple port burner are much smaller than those of the double port burner. For the triple port burner, due to the center air injection, the fuel consumption occurs in both inner and outer flames. On the other hand, for the double port burner, the oxygen is supplied from one side air, and as a result, the fuel consumption rate is relatively lower. Hence, by the center air injection, the fuel consumption is largely accelerated, resulting in the reduction of PAH and soot.

  9. Study of remobilization polycyclic aromatic hydrocarbons (PAHs) in contaminated matrices

    International Nuclear Information System (INIS)

    Belkessam, L.; Vessigaud, S.; Laboudigue, A.; Vessigaud, S.; Perrin-Ganier, C.; Schiavon, M.; Denys, S.

    2005-01-01

    Polycyclic aromatic hydrocarbons (PAHs) originate from many pyrolysis processes. They are widespread environmental pollutants because some of them present toxic and genotoxic properties. In coal pyrolysis sites such as former manufactured gas plants and coke production plants, coal tar is a major source of PAHs. The management of such sites requires better understanding of the mechanisms that control release of PAHs to the biosphere. Determining total PAH concentrations is not sufficient since it does not inform about the pollutants availability to environmental processes. The fate and transport of PAHs in soil are governed by sorption and microbial processes which are well documented. Globally, enhancing retention of the compounds by a solid matrix reduces the risk of pollutant dispersion, but decreases their accessibility to microbial microflora. Conversely, the remobilization of organics from contaminated solid matrices represents a potential hazard since these pollutants can reach groundwater resources. However the available data are often obtained from laboratory experiments in which many field parameters can not be taken into account (long term, temperature, co-pollution, ageing phenomenon, heterogenous distribution of pollution). The present work focuses on the influence assessment and understanding of some of these parameters on PAHs remobilization from heavily polluted matrices in near-field conditions (industrial contaminated matrices, high contact time, ..). Results concerning effects of temperature and physical state of pollution (dispersed among the soil or condensed in small clusters or in coal tar) are presented. (authors)

  10. Contamination characteristics and source apportionment of methylated PAHs in agricultural soils from Yangtze River Delta, China

    International Nuclear Information System (INIS)

    Chen, Weixiao; Wu, Xinyi; Zhang, Haiyun; Sun, Jianteng; Liu, Wenxin; Zhu, Lizhong; Li, Xiangdong; Tsang, Daniel C.W.; Tao, Shu; Wang, Xilong

    2017-01-01

    Alkylated PAHs (APAHs) have been shown to be more toxic and persistent than their non-alkylated parent compounds. However, little is known about the extent of soil contamination by these pollutants. To help understand agricultural soil pollution by these compounds at a regional scale, a total of 18 methylated PAHs (MPAHs, a major class of APAHs) in 243 soil samples were analyzed. These soil samples were collected from 11 sites in the Yangtze River Delta (YRD) region, a representative fast developing area in China. The total concentration of MPAHs (∑18MPAHs) ranged from 5.5 to 696.2 ng/g dry soil, with methylnaphthalenes (M-NAPs) and methylphenanthrenes (M-PHEs) accounting for more than 70% of the compositional profile. Relatively high concentrations of ∑18MPAHs were found in Jiaxing and Huzhou areas of Zhejiang province, as well as on the border between the cities of Wuxi and Suzhou. Different MPAH groups showed dissimilar spatial distribution patterns. The spatial distribution of lower molecular weight MPAHs was related to agricultural straw burning and emissions/depositions from industrial activities, whereas that of higher molecular weight MPAHs was much more a function of the total organic carbon (TOC) content of soil. Although coal, biomass (crop straw and wood), and petroleum combustion were identified to be the major emission sources for most of the sampling sites, the areas with relatively severe pollution with ∑18MPAHs resulted from the localized hotspots of petroleum leakage. Isomeric MPAHs with methyl group substituted at 2- (β) position exhibited significantly higher concentrations than those substituted at 1- (α) position. Results of this work help to understand soil pollution by MPAHs, and are useful for designing effective strategies for pollution control so as to ensure food safety in areas with fast economic growth. - Highlights: • Several 2–4 rings methyl-PAHs were investigated in soils from Yangtze River Delta. • Higher levels of

  11. Enhanced Accessibility of Polycyclic Aromatic Hydrocarbons (PAHs) and Heterocyclic PAHs in Industrially Contaminated Soil after Passive Dosing of a Competitive Sorbate

    DEFF Research Database (Denmark)

    Humel, Stefan; Nørgaard Schmidt, Stine; Sumetzberger-Hasinger, Marion

    2017-01-01

    To assess the exposure to polycyclic aromatic hydrocarbons (PAHs) it is important to understand the binding mechanisms between specific soil constituents and the organic pollutant. In this study, sorptive bioaccessibility extraction (SBE) was applied to quantify the accessible PAH fraction...... in industrially contaminated soil with and without passive dosing of a competitive sorbate. SBE experiments revealed an accessible PAH fraction of 41 ± 1% (∑16 US EPA PAHs + 5 further PAHs). The passive dosing of toluene below its saturation level revealed competitive binding and resulted in an average increase.......4% PAH. We explain increased PAH desorption after addition of toluene by competitive adsorption to high-affinity sorption sites while acknowledging that toluene could additionally have increased PAH mobility within the soil matrix. Findings suggest that the presence of copollutants at contaminated sites...

  12. Bioremediation of PAH contaminated soil samples

    International Nuclear Information System (INIS)

    Joshi, M.M.; Lee, S.

    1994-01-01

    Soils contaminated with polynuclear aromatic hydrocarbons (PAHs) pose a hazard to life. The remediation of such sites can be done using physical, chemical, and biological treatment methods or a combination of them. It is of interest to study the decontamination of soil using bioremediation. The experiments were conducted using Acinetobacter (ATCC 31012) at room temperature without pH or temperature control. In the first series of experiments, contaminated soil samples obtained from Alberta Research Council were analyzed to determine the toxic contaminant and their composition in the soil. These samples were then treated using aerobic fermentation and removal efficiency for each contaminant was determined. In the second series of experiments, a single contaminant was used to prepare a synthetic soil sample. This sample of known composition was then treated using aerobic fermentation in continuously stirred flasks. In one set of flasks, contaminant was the only carbon source and in the other set, starch was an additional carbon source. In the third series of experiments, the synthetic contaminated soil sample was treated in continuously stirred flasks in the first set and in fixed bed in the second set and the removal efficiencies were compared. The removal efficiencies obtained indicated the extent of biodegradation for various contaminants, the effect of additional carbon source, and performance in fixed bed without external aeration

  13. THE INFRARED SPECTROSCOPY OF POLYCYCLIC AROMATIC HYDROCARBONS WITH FIVE- AND SEVEN-MEMBERED FUSED RING DEFECTS

    International Nuclear Information System (INIS)

    Ricca, Alessandra; Bauschlicher, Charles W. Jr; Allamandola, Louis J.

    2011-01-01

    Polycyclic aromatic hydrocarbon (PAH) growth and destruction are thought to proceed via the occasional incorporation of five- and seven-membered fused ring defects in the hexagonal carbon skeleton. Using density functional theory, this paper investigates the effect such five- and seven-membered fused ring defects have on the infrared spectra of ovalene, circumovalene, and circumcircumovalene. The defects make only small changes to the overall infrared (IR) spectra, both in the mid-IR and in the far-IR, of these species. In addition to small shifts in the positions of the bands between the PAHs with and without defects, the most common effect of the defects is to increase the number of bands. Except for an anion with the Stone-Wales defect, all of the species studied have the C-C stretching band at 6.3 μm or at longer wavelengths, the position in Classes B and C astronomical PAH spectra. In the case of the Stone-Wales anion, the band falls at 6.20 μm, suggesting that further study of defects is probably worthwhile, as some PAHs with defects might be important in those sources (Class A) that show a C-C stretching band that falls near 6.2 μm.

  14. Contribution of Fossil Fuels and Wood Combustion to Carcinogenic PAHs in the Ambient Atmosphere of a Tropical Megacity

    Science.gov (United States)

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

    2015-12-01

    Weekly particulate matter sampling was carried out at a peri-urban site located in megacity Delhi, India for 1 year (2009-2010) and the annual mean PM10 level was found to be ˜9 times the World Health Organization limit. Seasonal variation of PAHs (range 37.2-74.0 ng m-3) was significant with winter values being 72% and 68% higher than summer and monsoon respectively. Principal component analysis coupled with multiple linear regression identified diesel, natural gas and lubricating oil combustion (49.5%), wood combustion (25.4%), gasoline (15.5%) and coal combustion (9.6%) sources for the observed PAHs. Heavy traffic on the national highway and arterial roads and domestic emissions from suburban households in the vicinity of the site appeared to have significantly affected its air quality. A substantial portion (˜55%) of the aerosol PAH load was comprised of carcinogenic species, which yielded a considerably high lifetime inhalation cancer risk estimate (8.7E-04). If considered as a conservative lower-bound estimate, this risk translates into ˜211 excess cancer cases for lifetime inhalation exposure to the observed PAH concentrations in Delhi.

  15. EBT ring physics

    International Nuclear Information System (INIS)

    Uckan, N.A.

    1980-04-01

    This workshop attempted to evaluate the status of the current experimental and theoretical understanding of hot electron ring properties. The dominant physical processes that influence ring formation, scaling, and their optimal behavior are also studied. Separate abstracts were prepared for each of the 27 included papers

  16. Observational Evidence Linking Interstellar UV Absorption to PAH Molecules

    Energy Technology Data Exchange (ETDEWEB)

    Blasberger, Avi; Behar, Ehud; Perets, Hagai B. [Department of Physics, Technion (Israel); Brosch, Noah [The Wise Observatory and School of Physics and Astronomy, Tel Aviv University (Israel); Tielens, Alexander G. G. M. [Leiden Observatory, Leiden University (Netherlands)

    2017-02-20

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

  17. Observational Evidence Linking Interstellar UV Absorption to PAH Molecules

    International Nuclear Information System (INIS)

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

    2017-01-01

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

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

    NARCIS (Netherlands)

    Martena, M.J.; Grutters, M.; Groot, de H.N.; Konings, E.J.M.; Rietjens, I.

    2011-01-01

    Food supplements can contain polycyclic aromatic hydrocarbons (PAH). The European Food Safety Authority (EFSA) has defined 16 priority PAH that are both genotoxic and carcinogenic and identified eight priority PAH (PAH8) or four of these (PAH4) as good indicators of the toxicity and occurrence of

  19. Biodegradation, bioaccessibility, and genotoxicity of diffuse polycyclic aromatic hydrocarbon (PAH) pollution at a motorway site

    DEFF Research Database (Denmark)

    Johnsen, A.R.; de Lipthay, J.R.; Reichenberg, F.

    2006-01-01

    the asphalt pavement and tested for total amounts of PAHs, amounts of bioaccessible PAHs, total bacterial populations, PAH degrader populations, the potential for mineralization of C-14-PAHs, and mutagenicity. Elevated PAH concentrations were found in the samples taken 1-8 m from the pavement. Soil sampled...... in the most polluted samples close to the pavement. Hydroxypropyl-beta-cyclodextrin extraction of soil PAHs, as a direct estimate of the bioaccessibility, indicated that only 1-5% of the PAHs were accessible to soil bacteria. This low bioaccessibility is suggested to be due to sorption to traffic soot...... particles. The increased PAH level close to the pavement was reflected in slightly increased mutagenic activity (1 m, 0.32 +/- 0.08 revertants g(-1) soil; background/24 m: 0.08 +/- 0.04), determined by the Salmonella/microsome assay of total extractable PAHs activated by liver enzymes. The potential...

  20. Biodegradation, bioaccessibility, and genotoxicity of diffuse polycyclic aromatic hydrocarbon (PAH) pollution at a motorway site

    DEFF Research Database (Denmark)

    Johnsen, A.R.; de Lipthay, J.R.; Reichenberg, F.

    2006-01-01

    Diffuse pollution of surface soil with polycyclic aromatic hydrocarbons (PAHs) is problematic in terms of the large areas and volumes of polluted soil. The levels and effects of diffuse PAH pollution at a motorway site were investigated. Surface soil was sampled with increasing distance from...... in the most polluted samples close to the pavement. Hydroxypropyl-beta-cyclodextrin extraction of soil PAHs, as a direct estimate of the bioaccessibility, indicated that only 1-5% of the PAHs were accessible to soil bacteria. This low bioaccessibility is suggested to be due to sorption to traffic soot...... the asphalt pavement and tested for total amounts of PAHs, amounts of bioaccessible PAHs, total bacterial populations, PAH degrader populations, the potential for mineralization of C-14-PAHs, and mutagenicity. Elevated PAH concentrations were found in the samples taken 1-8 m from the pavement. Soil sampled...

  1. On the role of resonantly stabilized radicals in polycyclic aromatic hydrocarbon (PAH) formation: pyrene and fluoranthene formation from benzyl-indenyl addition.

    Science.gov (United States)

    Sinha, Sourab; Rahman, Ramees K; Raj, Abhijeet

    2017-07-26

    Resonantly stabilized radicals, such as propargyl, cyclopentadienyl, benzyl, and indenyl, play a vital role in the formation and growth of polycyclic aromatic hydrocarbons (PAHs) that are soot precursors in engines and flames. Pyrene is considered to be an important PAH, as it is thought to nucleate soot particles, but its formation pathways are not well known. This paper presents a reaction mechanism for the formation of four-ring aromatics, pyrene and fluoranthene, through the combination of benzyl and indenyl radicals. The intermediate species and transition structures involved in the elementary reactions of the mechanism were studied using density functional theory, and the reaction kinetics were evaluated using transition state theory. The barrierless addition of benzyl and indenyl to form the adduct, 1-benzyl-1H-indene, was found to be exothermic with a reaction energy of 204.2 kJ mol -1 . The decomposition of this adduct through H-abstraction and H 2 -loss was studied to determine the possible products. The rate-of-production analysis was conducted to determine the most favourable reactions for pyrene and fluoranthene formation. The premixed laminar flames of toluene, ethylbenzene, and benzene were simulated using a well-validated hydrocarbon fuel mechanism with detailed PAH chemistry after adding the proposed reactions to it. The computed and experimentally observed species profiles were compared to determine the effect of the new reactions for pyrene and fluoranthene formation on their concentration profiles. The role of benzyl and indenyl combination in PAH formation and growth is highlighted.

  2. Polycyclic Aromatic Hydrocarbon (pah) In The Bulk Precipitation of The Seine Estuary, France

    Science.gov (United States)

    Motelay-Massei, A.; Ollivon, D.; Garban, B.; Chevreuil, M.

    The evolution of industry and the rising of population have resulted in deep changes in the quality of the environment. Nowadays much more often the attention of analysts is focused on the presence of organic pollutants in precipitation, such as polycyclic aromatic hydrocarbons or pesticides. Atmospheric inputs play a significant role in semivolatile chemicals cycling and alter so the hydrological cycle. PAHs are semi- volatile organic contaminants of great environmental concern because of their car- cinogenic properties. PAHs are produced primarily during incomplete combustion of fossil fuels and wood. Major sources of PAHs to urban atmosphere include au- tomobile traffic, home heating, municipal incinerators and industrial emissions. De- spite their production in urban and industrial sites, PAHs occur at high concentra- tions in rural areas due to their persistence and ability to be transported over long distances. The aim of this investigation was to obtain information about occurrence of organic trace components in precipitation in the Seine Estuary. It was also of in- terest to investigate the spatial and temporal variability of PAHs in the bulk (wet and dry) deposition occurring in the estuary region and to estimate PAH deposition flux on watershed (urban, industrial or rural). Precipitation samples were collected at four locations in the Seine Estuary: the first is an industrial site (Le Havre), two are urban sites (Rouen, representative of urban area influenced by heavy traffic and Notre-Dame de Gravenchon, near from an industrial center) and the last one is ru- ral (Evreux). Each of the sites is located close to a meteorological station. Sam- pling is performed weekly since March 2001. In our analytical conditions, "total PAH" includes 15 compounds: naphthalene (NAP), acenaphtene (ACE), phenanthrene (PHE), anthracene (ANT), fluoranthene (FTH), pyrene (PYR), benzo(a)anthracene (BaA), chrysene (CHR), benzo(b)fluoranthene (BbF), benzo(k)fluoranthene (Bk

  3. Polycyclic Aromatic Hydrocarbons as Plausible Prebiotic Membrane Components

    Science.gov (United States)

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

    2012-08-01

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

  4. On the Laurent polynomial rings

    International Nuclear Information System (INIS)

    Stefanescu, D.

    1985-02-01

    We describe some properties of the Laurent polynomial rings in a finite number of indeterminates over a commutative unitary ring. We study some subrings of the Laurent polynomial rings. We finally obtain two cancellation properties. (author)

  5. PAHs sensitivity of picophytoplankton populations in the Red Sea.

    Science.gov (United States)

    Kottuparambil, Sreejith; Agusti, Susana

    2018-04-25

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

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

    Science.gov (United States)

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

    2009-07-15

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

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

    Science.gov (United States)

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

    2014-08-01

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

  8. PAHs sensitivity of picophytoplankton populations in the Red Sea

    KAUST Repository

    Kottuparambil, Sreejith

    2018-04-25

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

  9. Effect of prenatal PAH exposure on birth outcomes and neurocognitive development in a cohort of newborns in Poland. Study design and preliminary ambient data

    Energy Technology Data Exchange (ETDEWEB)

    Jedrychowski, W.; Whyatt, R.M.; Camann, D.E.; Bawle, U.V.; Peki, K.; Spengler, J.D.; Dumyahn, T.S.; Penar, A.; Perera, F.F. [Jagiellonian University, Krakow (Poland). Department of Epidemiology and Preventive Medicine, Collegium Medicum

    2003-07-01

    Preliminary data suggest an association between infant mortality rates and several measures of ambient air pollution, including dustfall and polycyclic aromatic hydrocarbons (PAH). The effects of airborne PAH components on fetal growth and early childhood development are of primary interest since we have previously demonstrated that these pollutants were associated with significant decrements in birth weight, length and head circumference in Polish newborn babies. The undertaken research combines a state-of-the-art environmental monitoring and molecular approaches with comprehensive neurodevelopment assessments. A further innovation is the incorporation of biomarkers (lead and antioxidants in cord blood) to control for potential confounding of exposure-effect. The mean overall concentrations of specific PAH compounds in Krakow, Poland were highest for benzo(b)fluoranthene (23 ng/m{sup 3}), benzo(a)anthracene, indeno(1,2,3-cd)pyrene, chyresene and benzo(a)pyrene. Concentrations of the PAH compounds measured by personal monitoring were higher in residents of the higher polluted area of the city. Comparison between the Krakow and New York City ambient data demonstrates that the concentrations and proportions of specific compounds in the total PAH mixture differ widely across these cities. Thus, one may expect that the PAH-related health risks would differ between the two areas not only because exposures are different, but also because the PAH profile differs. Presumably, this different profile is a consequence of variations in the sources of fossil and solid fuels used to produce energy. In Poland, more coal is used than in New York City. Auto emissions for example, are low in benzo(a)pyrene, whereas such emissions from refuse burning are high. 31 refs.

  10. Heavy ion storage rings

    International Nuclear Information System (INIS)

    Schuch, R.

    1987-01-01

    A brief overview of synchrotron storage rings for heavy ions, which are presently under construction in different accelerator laboratories is given. Ions ranging from protons up to uranium ions at MeV/nucleon energies will be injected into these rings using multiturn injection from the accelerators available or being built in these laboratories. After injection, it is planned to cool the phase space distribution of the ions by merging them with cold electron beams or laser beams, or by using stochastic cooling. Some atomic physics experiments planned for these rings are presented. 35 refs

  11. Faithfully quadratic rings

    CERN Document Server

    Dickmann, M

    2015-01-01

    In this monograph the authors extend the classical algebraic theory of quadratic forms over fields to diagonal quadratic forms with invertible entries over broad classes of commutative, unitary rings where -1 is not a sum of squares and 2 is invertible. They accomplish this by: (1) Extending the classical notion of matrix isometry of forms to a suitable notion of T-isometry, where T is a preorder of the given ring, A, or T = A^2. (2) Introducing in this context three axioms expressing simple properties of (value) representation of elements of the ring by quadratic forms, well-known to hold in

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

    International Nuclear Information System (INIS)

    Wang, Ruwei; Liu, Guijian; Zhang, Jiamei

    2015-01-01

    Coal-fired power plants (CFPPs) represent important source of atmospheric PAHs, however, their emission characterization are still largely unknown. In this work, the concentration, distribution and gas-particle partitioning of PM_1_0- and gas-phase PAHs in flue gas emitted from different coal-fired utility boilers were investigated. Moreover, concentration and distribution in airborne PAHs from different functional areas of power plants were studied. People's inhalatory and dermal exposures to airborne PAHs at these sites were estimated and their resultant lung cancer and skin cancer risks were assessed. Results indicated that the boiler capacity and operation conditions have significant effect on PAH concentrations in both PM_1_0 and gas phases due to the variation of combustion efficiency, whereas they take neglected effect on PAH distributions. The wet flue gas desulphurization (WFGD) takes significant effect on the scavenging of PAH in both PM_1_0 and gas phases, higher scavenging efficiency were found for less volatile PAHs. PAH partitioning is dominated by absorption into organic matter and accompanied by adsorption onto PM_1_0 surface. In addition, different partitioning mechanism is observed for individual PAHs, which is assumed arising from their chemical affinity and vapor pressure. Risk assessment indicates that both inhalation and dermal contact greatly contribute to the cancer risk for CFPP workers and nearby residents. People working in workshop are exposed to greater inhalation and dermal exposure risk than people living in nearby vicinity and working office. - Highlights: • PAH distribution in PM_1_0 and gas phases primarily depend on the vapor pressure. • Combustion conditions and WFGD show typical effects on PAH level and profile. • PAH partitioning is dominated by absorption and also accompanied by adsorption. • Individual PAHs show different partitioning mechanisms in PM_1_0- and gas-phases. • People in workshop suffer greater cancer

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

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ruwei [CAS Key Laboratory of Crust-Mantle and the Environment, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui (China); State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, The Chinese Academy of Sciences, Xi' an 710075, Shanxi (China); Liu, Guijian, E-mail: lgj@ustc.edu.cn [CAS Key Laboratory of Crust-Mantle and the Environment, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui (China); State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, The Chinese Academy of Sciences, Xi' an 710075, Shanxi (China); Zhang, Jiamei [CAS Key Laboratory of Crust-Mantle and the Environment, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui (China)

    2015-12-15

    Coal-fired power plants (CFPPs) represent important source of atmospheric PAHs, however, their emission characterization are still largely unknown. In this work, the concentration, distribution and gas-particle partitioning of PM{sub 10}- and gas-phase PAHs in flue gas emitted from different coal-fired utility boilers were investigated. Moreover, concentration and distribution in airborne PAHs from different functional areas of power plants were studied. People's inhalatory and dermal exposures to airborne PAHs at these sites were estimated and their resultant lung cancer and skin cancer risks were assessed. Results indicated that the boiler capacity and operation conditions have significant effect on PAH concentrations in both PM{sub 10} and gas phases due to the variation of combustion efficiency, whereas they take neglected effect on PAH distributions. The wet flue gas desulphurization (WFGD) takes significant effect on the scavenging of PAH in both PM{sub 10} and gas phases, higher scavenging efficiency were found for less volatile PAHs. PAH partitioning is dominated by absorption into organic matter and accompanied by adsorption onto PM{sub 10} surface. In addition, different partitioning mechanism is observed for individual PAHs, which is assumed arising from their chemical affinity and vapor pressure. Risk assessment indicates that both inhalation and dermal contact greatly contribute to the cancer risk for CFPP workers and nearby residents. People working in workshop are exposed to greater inhalation and dermal exposure risk than people living in nearby vicinity and working office. - Highlights: • PAH distribution in PM{sub 10} and gas phases primarily depend on the vapor pressure. • Combustion conditions and WFGD show typical effects on PAH level and profile. • PAH partitioning is dominated by absorption and also accompanied by adsorption. • Individual PAHs show different partitioning mechanisms in PM{sub 10}- and gas-phases. • People in

  14. CMS : the first barrel ring completed !

    CERN Multimedia

    Laurent Guiraud

    2000-01-01

    On 14 November, the CMS collaboration and the German firm DWE celebrated the successful construction of the detector's first yoke barrel ring. To mark the occasion, those in charge of the construction at CERN and DWE posed for the camera in the middle of the giant component.

  15. Lateral ring metal elastic wheel absorbs shock loading

    Science.gov (United States)

    Galan, L.

    1966-01-01

    Lateral ring metal elastic wheel absorbs practically all shock loading when operated over extremely rough terrain and delivers only a negligible shock residue to associated suspension components. The wheel consists of a rigid aluminum assembly to which lateral titanium ring flexible elements with treads are attached.

  16. Tunable plasmonic filter with circular metal–insulator– metal ring ...

    Indian Academy of Sciences (India)

    The mechanism based on circular ring resonators with narrow gaps may provide a novel method for designing all-optical integrated components in optical communication and computing. Keywords. Metal–insulator–metal waveguide; surface plasmon; optical filters; ring resonator. PACS Nos 42.79.−e; 73.20.Mf; 78.20.Bh. 1.

  17. PAHs in corn grains submitted to drying with firewood.

    Science.gov (United States)

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

    2017-01-15

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

  18. Intestinal metabolism of PAH: in vitro demonstration and study of its impact on PAH transfer through the intestinal epithelium

    International Nuclear Information System (INIS)

    Cavret, Severine; Feidt, Cyril

    2005-01-01

    Food would seem to be one of the main ways of animal and human contamination with polycyclic aromatic hydrocarbons (PAHs). In vivo studies suggest a transfer in intestinal epithelium by diffusion, which appears extensively governed by the physicochemical properties of PAHs, particularly lipophilicity. However, other mechanisms, such as metabolism, are considered to intervene. Our work aimed at testing in vitro intestinal metabolism and defining its impact on transepithelial transport of PAHs. Caco-2 cells were cultivated on permeable filters and incubated with 14 C-labeled benzo[a]pyrene (BaP), pyrene (Pyr), and phenanthrene (Phe), which differ in their physicochemical properties. The results showed that the cells were able to metabolize the compounds. In basal media, Phe appeared to be the least hydroxylated molecule (45% after a 6-h exposure), followed by Pyr (65%) and finally BaP (96%). Inhibition of PAH metabolism showed a determinant effect on kinetics profiles. Transfer in the basal compartment of BaP, Pyr, and Phe radioactivities was, respectively, 26, 4, and 2 times lower with inhibitors, corroborating that intestinal metabolism of PAHs would have a positive impact on their transfer, an impact that increased with their lipophilicity. Furthermore, after a 6-h incubation, metabolites were also detected in apical medium. These findings suggested that intestinal metabolism might play a key role in intestinal barrier permeability and thus in the bioavailability of tested micropollutants

  19. The g-2 ring

    CERN Multimedia

    1974-01-01

    The precise measurement of "g-2", the anomalous magnetic moment of the muon, required a special muon storage ring with electrostatic focussing and very accurate knowledge of the magnetic bending field. For more details see under photo 7405430.

  20. INJECTION EFFICIENCY IN COMPTON RING NESTOR

    Directory of Open Access Journals (Sweden)

    P. I. Gladkikh

    2017-12-01

    Full Text Available NESTOR is the hard X-ray source that is under commissioning at NSC KIPT. NESTOR based on the Compton scattering of laser photons on relativistic electrons. The structure of the facility can be represented as the following components: a linear accelerator, a transport channel, a storage ring, and a laser-optical system. Electrons are stored in the storage ring for energy of 40-200 MeV. Inevitable alignment errors of magnetic elements are strongly effect on the beam dynamics in the storage ring. These errors lead to a shift of the equilibrium orbit relative to the ideal one. Significant shift of the equilibrium orbit could lead to loss of the beam on physical apertures. Transverse sizes of electron and laser beams are only few tens of microns at the interaction point. The shift of electron beam at the interaction point could greatly complicate the operation adjustment of storage ring without sufficient beam position diagnostic system. This article presents the simulation results of the efficiency of electron beam accumulation in the NESTOR storage ring. Also, this article is devoted to electron beam dynamics due to alignment errors of magnetic element in the ring.

  1. [Liesegang's rings resembling helminthiasis].

    Science.gov (United States)

    Zámecník, M; Riedl, I

    1996-12-01

    So called Liesegang's rings are lamellar corpuscles which develop after periodical precipitation of oversaturated solutions in gel medium. They can occur in cysts, closed cavities, inflammatory exudates and necroses. They resemble parasitic eggs, larvae or adult forms. A case of 28-year-old woman is presented with many Liesegang's rings in a stuff from dilated renal calyx. Their preliminary evaluation considered helminths, especially Dioctophyma renale.

  2. Storage ring group summary

    International Nuclear Information System (INIS)

    King, N.M.

    1980-01-01

    The Storage Ring Group set out to identify and pursue salient problems in accelerator physics for heavy ion fusion, divorced from any particular reference design concept. However, it became apparent that some basic parameter framework was required to correlate the different study topics. As the Workshop progressed, ring parameters were modified and updated. Consequently, the accompanying papers on individual topics will be found to refer to slightly varied parameters, according to the stage at which the different problems were tackled

  3. The rings of Uranus

    Science.gov (United States)

    Elliot, J. L.; Dunham, E.; Mink, D.

    1977-01-01

    A description is given of the observation of five brief occultations of the star SAO 158687 which occurred both before and after its occultation by Uranus on March 10, 1977. The events were observed with a three-channel occultation photometer, attached to a 91-cm telescope. The observations indicate that at least five rings encircle the planet Uranus. Possible reasons for the narrowness of the Uranus rings are discussed.

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

    Science.gov (United States)

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

    2014-01-01

    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 ∼200 cm 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.

  5. Decontamination of PAH polluted soils by fungi. Subproject: PAH degradation balance and testing of the extended laboratory process. Final report; Dekontamination von PAK belasteten Boeden durch Pilze. Teilprojekt: Bilanzierung des PAK-Abbaus und Erprobung des erweiterten Laborverfahrens. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Martens, R.; Zadrazil, F.; Wolter, M.; Bahadir, M.

    1997-09-01

    The aim of the research project was first to select a fungus with a high potential for mineralization of polycyclic aromatic hydrocarbons (PAH) and a good ability to colonize different soils. The application of this fungus for a degradation of PAH in soil had to be tested. In a screening of 57 white rot fungi the fungus Pleurotus sp. Florida fulfilled these requirements best. In pure culture it was able to metabolize and mineralize highly condensed 4-6 ring PAH to a great extent. For instance, up to 50% of {sup 14}C-pyrene or 39% of {sup 14}C-benzo(a)pyrene was mineralized to {sup 14}CO{sub 2} within 15 weeks. If different carriers for {sup 14}C-pyrene were used the mineralization correlated with the bioavailability, which was characterized by the desorption of the compound from the carriers with water. The mineralization of {sup 14}C-pyrene, {sup 14}C-benz(a)anthracene; {sup 14}C-benzo(a)-pyrene and {sup 14}C-dibenz(a, h)anthracene in native soils showed that a colonization with Pl. sp Florida inhibited the degradation of the less recalcitrant {sup 14}C-pyrene by the indigenous soil microflora. However, the mineralization of the carcinogenic, very recalcitrant and high condensed {sup 14}C-PAH was considerably supported by the fungus. Therefore this capabilities of the fungus could not be proven in a joint medium-scale soil experiment (0.8 m{sup 3} soil) which had been conducted within a parmership with scientists in Jena and an industriell firm. Because of safety aspects only the low condensed less recalcitrant PAH could be applied in this experiment. (orig./MG) [Deutsch] Ziel der Untersuchungen war es, zunaechst aus einer groesseren Zahl von Weissfaeulepilzen Pilze zu selektieren, die ein hohes Abbaupotential fuer PAK besitzen. Fuer die effektive Bildung der fuer den Xenobiotika-Abbau wahrscheinlich verantwortlichen lignolytischen Enzyme sollten die Pilze auf Stroh mit einer Kontamination von {sup 14}C-Pyren angezogen werden. An Hand der Freisetzung von {sup 14

  6. Evaluation of bio-remediation technologies for PAHs contaminated soils

    International Nuclear Information System (INIS)

    Garcia Frutos, F.J.; Diaz, J.; Rodriguez, V.; Escolano, O.; Garcia, S.; Perez, R.; Martinez, R.; Oromendia, R.

    2005-01-01

    Natural attenuation is a new concept related to polluted soil remediation. Can be understood like an 'in situ' bio-remediation process with low technical intervention. This low intervention may be in order to follow the behaviour of pollutants 'monitored natural attenuation' or include an optimisation process to improve biological remediation. The use of this technology is a fact for light hydrocarbon polluted soil, but few is known about the behaviour of polycyclic aromatic hydrocarbons (PAHs) in this process. PAHs are more recalcitrant to bio-remediation due to their physic-chemical characteristics, mainly hydrophobicity and electrochemical stability. PAHs are a kind of pollutants widely distributed in the environment, not only in the proximity of the source. This linked to the characteristics of some of them related to toxicity and mutagenicity implies its inclusion as target compounds from an environmental point of view. Their low availability, solubility and the strong tendency to bind to soil particle, especially to the organic phase affect PAHs biological mineralisation. So, if the pollutant is not available to microorganisms it can not be bio-degraded. Bioavailability can be assessed form several but complementary points of view: physico-chemical and biological. First including the term availability and the second to point out the capacity of soil microorganisms to mineralize PAHs. Availability and Bio-degradability must be determined, as well as the presence and activity of specific degraders among the soil organisms, once settled these points is necessary to study the biological requirements to optimise biodegradation kinetics of these compounds. In this work we present a study carried out on a soil, contaminated by PAHs, the study includes three main topics: bioavailability assessment (both term availability and bio-degradability), bio-remediation assessment, once optimised conditions for natural attenuation and finally a simulation of the

  7. Strong Impact on the Polycyclic Aromatic Hydrocarbon (PAH)-Degrading Community of a PAH-Polluted Soil but Marginal Effect on PAH Degradation when Priming with Bioremediated Soil Dominated by Mycobacteria

    DEFF Research Database (Denmark)

    Johnsen, Anders R.; Schmidt, Stine; Hybholdt, Trine K.

    2007-01-01

    Bioaugmentation of soil polluted with polycyclic aromatic hydrocarbons (PAHs) is often disappointing because of the low survival rate and low activity of the introduced degrader bacteria. We therefore investigated the possibility of priming PAH degradation in soil by adding 2% of bioremediated soil...... with a high capacity for PAH degradation. The culturable PAH-degrading community of the bioremediated primer soil was dominated by Mycobacterium spp. A microcosm containing pristine soil artificially polluted with PAHs and primed with bioremediated soil showed a fast, 100- to 1,000-fold increase in numbers...... of culturable phenanthrene-, pyrene-, and fluoranthene degraders and a 160-fold increase in copy numbers of the mycobacterial PAH dioxygenase gene pdo1. A nonpolluted microcosm primed with bioremediated soil showed a high rate of survival of the introduced degrader community during the 112 days of incubation...

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

    Science.gov (United States)

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

    2012-01-01

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

  9. PAH growth initiated by propargyl addition: Mechanism development and computational kinetics

    KAUST Repository

    Raj, Abhijeet Dhayal; Rachidi, Mariam El; Chung, Suk-Ho; Sarathy, Mani

    2014-01-01

    Polycyclic aromatic hydrocarbon (PAH) growth is known to be the principal pathway to soot formation during fuel combustion, as such, a physical understanding of the PAH growth mechanism is needed to effectively assess, predict, and control soot

  10. Biological risk and pollution history of polycyclic aromatic hydrocarbons (PAHs) in Nansha mangrove, South China.

    Science.gov (United States)

    Wu, Qihang; Leung, Jonathan Y S; Tam, Nora F Y; Chen, Shejun; Mai, Bixian; Zhou, Xizhen; Xia, Lihua; Geng, Xinhua

    2014-08-15

    Chinese government has taken various measures to alleviate pollution caused by polycyclic aromatic hydrocarbons (PAHs) in the region of Pearl River Delta since the economic reform in 1978, but the effectiveness of these measures remains largely unknown. This study aimed to elucidate the biological risk and pollution history of PAHs by measuring the concentrations of 28 PAHs in the surface and core sediments, respectively, in Nansha mangrove. Results found that the biological risk of PAHs was low without obvious spatial variation. The PAH concentration along the depth gradient indicated that PAH pollution was stabilized since the early 1990s while the source of PAHs has gradually changed from combustion of coal to petroleum products. This implied that the mitigation measures taken by the Chinese government were effective. Compared to marine bottom sediment, we propose that using mangrove sediment can provide a more accurate and precise estimate of pollution history of PAHs. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Structural dynamics of PAH molecules upon energetic photon or ion interactions

    NARCIS (Netherlands)

    Reitsma, Geert

    2014-01-01

    Polycyclische aromatische koolwaterstoffen (PAHs) vormen een hele bijzondere familie van moleculen. PAHs bestaan uit ringen van koolstofatomen en hebben waterstofatomen op de randen. Zo ontstaan platte en heel erg stabiele moleculen. Deze moleculen komen overal voor, bijvoorbeeld in uitlaatgassen en

  12. Multispecies and monoculture rhizoremediation of polycyclic aromatic hydrocarbons (PAHs) from the soil

    CSIR Research Space (South Africa)

    Maila, MP

    2005-01-01

    Full Text Available In this study, the authors investigated the potential of multispecies rhizoremediation and monoculture rhizoremediation in decontaminating polycyclic aromatic hydrocarbon (PAH) contaminated soil. Plant-mediated PAH dissipation was evaluated using...

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

    DEFF Research Database (Denmark)

    Marchal, Geoffrey; Smith, Kilian E.C.; Mayer, Philipp

    2014-01-01

    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...

  14. Splicing of phenylalanine hydroxylase (PAH) exon 11 is vulnerable - Molecular pathology of mutations in PAH exon 11

    DEFF Research Database (Denmark)

    Heintz, Caroline; Dobrowolski, Steven F.; Andersen, Henriette Skovgaard

    2012-01-01

    as a vulnerable exon and used patient derived lymphoblast cell lines and PAH minigenes to study the molecular defect that impacted pre-mRNA processing. We showed that the c.1144T>C and c.1066-3C>T mutations cause exon 11 skipping, while the c.1139C>T mutation is neutral or slightly beneficial. The c.1144T......In about 20-30% of phenylketonuria (PKU) patients, phenylalanine (Phe) levels can be controlled by cofactor 6R-tetrahydrobiopterin (BH(4)) administration. The phenylalanine hydroxylase (PAH) genotype has a predictive value concerning BH(4)-response and therefore a correct assessment of the mutation...... molecular pathology is important. Mutations that disturb the splicing of exons (e.g. interplay between splice site strength and regulatory sequences like exon splicing enhancers (ESEs)/exon splicing silencers (ESSs)) may cause different severity of PKU. In this study, we identified PAH exon 11...

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

    Science.gov (United States)

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

    2015-04-01

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

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

    Science.gov (United States)

    Wang, Ruwei; Liu, Guijian; Zhang, Jiamei

    2015-12-15

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

  17. An intensive monitoring campaign of PAHs for assessing the impact of a steel plant.

    Science.gov (United States)

    Di Gilio, A; Ventrella, G; Giungato, P; Tutino, M; Giua, R; Assennato, G; de Gennaro, G

    2017-02-01

    This study provided a useful approach for assessing the impact of industrial sources on surrounding, especially in a sensitive industrial area as Taranto (South of Italy). Taranto is one of the most industrialized Italian towns, where several emission sources operate simultaneously in proximity to the urban settlement. An intensive monitoring campaign of PAHs was carried out from January 28th to July 30th, 2011, in seven sites located in residential settlement around the industrial area and in the city center. The collected data were integrated with the information about wind direction and speed by means bivariate polarplot in order to characterize and localize the industrial sources. High BaP concentrations were detected especially when Benzene to Toluene ratio (B/T ratio) values excedeed 1 and all receptor sites were downwind to the steel plant. Moreover, in order to discriminate among PAH sources and quantify their contributions, a source apportionment analysis of the collected data was provided by means Principal component Analysis (PCA) and Positive Matrix Factorization (PMF) methods. Finally, the processing of PMF5.0 output by bivariate polar plot, confirmed the impact of steel plant on both industrial sites downwind the steel plant and the city center. B[a]P apportionment was quite similar for industrial and urban sites: the traffic source contributed only 11% and 24% to B[a]P measured at two sites, respectively. Therefore, the proximity of Taranto downtown to industrial pole makes negligible all other source contributions to PAH concentrations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Presence of PAH or HAC below 900 km in the Titan's stratosphere?

    Science.gov (United States)

    Cordier, Daniel; COURS, Thibaud; Rey, Michael; Maltagliati, Luca; Seignovert, Benoit; Biennier, Ludovic

    2016-10-01

    In 2006, during Cassini's 10th flyby of Titan (T10), Bellucci et al. (2009) observed a solar occultation by Titan's atmosphere through the solar port of the Cassini/VIMS instrument. These authors noticed the existence of an unexplained additional absorption superimposed to the CH4 3.3 microns band. Because they were unable to model this absorption with gases, they attributed this intriguing feature to the signature of solid state organic components. Kim et al. (2011) revisited the data collected by Bellucci et al. (2009) and they considered the possible contribution of aerosols formed by hydrocarbon ices. They specifically took into account C2H6, CH4, CH3CN, C5H12 and C6H12 ices. More recently, Maltagliati et al. (2015) analyzed a set of four VIMS solar occultations, corresponding to flybys performed between January 2006 and September 2011 at different latitudes. They confirmed the presence of the 3.3 µm absorption in all occultations and underlined the possible importance of gaseous ethane, which has a strong plateau of absorption lines in that wavelength range. In this work, we show that neither hydrocarbon ices nor molecular C2H6 cannot satisfactorily explain the observed absorption. Our simulations speak in favor of an absorption due to the presence of PAH molecules or HAC in the stratosphere of Titan. PAH have been already considered by Lopes-Puertas et al. (2013) at altitudes larger than ~900 km and tentatively identified in the stratosphere by Maltagliati et al. (2015); PAH and HAC are good candidates for Titan's aerosols precursors.

  19. Some Aspects of Ring Theory

    CERN Document Server

    Herstein, IN

    2011-01-01

    S. Amitsur: Associative rings with identities.- I.N. Herstein: Topics in ring theory.- N. Jacobson: Representation theory of Jordan algebras.- I. Kaplansky: The theory of homological dimension.- D. Buchsbaum: Complexes in local ring theory.- P.H. Cohn: Two topics in ring theory.- A.W. Goldie: Non-commutative localisation.

  20. Chemical characterization of polycyclic aromatic hydrocarbons (PAHs) in 2013 Rayong oil spill-affected coastal areas of Thailand.

    Science.gov (United States)

    Pongpiachan, S; Hattayanone, M; Tipmanee, D; Suttinun, O; Khumsup, C; Kittikoon, I; Hirunyatrakul, P

    2018-02-01

    Among Southeast Asian countries, Thailand has gradually accustomed to extremely prompt urbanization, motorization, and industrialization. Chonburi and Rayong provinces are two provinces involved in "eastern seaboard" industrial zones, which is an emerging economic region that plays a key role in Thailand's economy. The 2013 Rayong oil spill did not only cause damages to the coastal and maritime environment, but also undermine trust in the overall safety system and negatively affect the investor confidence. In this study, 69 coastal soils collected around Koh Samed Island were chemically extracted and analyzed for 15 PAHs by using a Shimadzu GCMS-QP2010 Ultra system comprising a high-speed performance system with ASSP function. In this study, numerous diagnostic binary ratios were applied to identify potential sources of PAHs. Advanced statistical techniques such as hierarchical cluster analysis coupled with principal component analysis were also conducted for further investigations of source identifications. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Polyaromatic hydrocarbon (PAH) degradation potential of a new acid tolerant, diazotrophic P-solubilizing and heavy metal resistant bacterium Cupriavidus sp. MTS-7 isolated from long-term mixed contaminated soil.

    Science.gov (United States)

    Kuppusamy, Saranya; Thavamani, Palanisami; Megharaj, Mallavarapu; Lee, Yong Bok; Naidu, Ravi

    2016-11-01

    An isolate of Cupriavidus (strain MTS-7) was identified from a long-term PAHs and heavy metals mixed contaminated soil with the potential to biodegrade both LMW and HMW PAHs with added unique traits of acid and alkali tolerance, heavy metal tolerance, self-nutrient assimilation by N fixation and P solubilization. This strain completely degraded the model 3 (150 mg L(-1) Phe), 4 (150 mg L(-1) Pyr) and 5 (50 mg L(-1) BaP) ring PAHs in 4, 20 and 30 days, respectively. It could mineralize 90-100% of PAHs (200 mg L(-1) of Phe and Pyr) within 15 days across pH ranging from 5 to 8 and even in the presence of toxic metal contaminations. During biodegradation, the minimum inhibitory concentrations were 5 (Cu(2+)) and 3 (Cd(2+), Pb(2+), Zn(2+)) mg L(-1) of the potentially bioavailable metal ions and over 17 mg L(-1) metal levels was lethal for the microbe. Further, it could fix 217-274 μg mL(-1) of N and solubilize 79-135 μg mL(-1) of P while PAHs degradation. MTS-7 as a superior candidate could be thus used in the enhanced bioaugmentation and/or phytoremediation of long-term mixed contaminated sites. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Size-distributions of n-alkanes, PAHs and hopanes and their sources in the urban, mountain and marine atmospheres over East Asia

    Directory of Open Access Journals (Sweden)

    Z. Wang

    2009-11-01

    Full Text Available Size-segregated (9 stages n-alkanes, polycyclic aromatic hydrocarbons (PAHs and hopanes in the urban (Baoji city in inland China, mountain (Mt. Tai in east coastal China and marine (Okinawa Island, Japan atmospheres over East Asia were studied using a GC/MS technique. Ambient concentrations of n-alkanes (1698±568 ng m−3 in winter and 487±145 ng m−3 in spring, PAHs (536±80 and 161±39 ng m−3, and hopanes (65±24 and 20±2.4 ng m−3 in the urban air are 1–2 orders of magnitude higher than those in the mountain aerosols and 2–3 orders of magnitude higher than those in the marine samples. Mass ratios of n-alkanes, PAHs and hopanes clearly demonstrate coal-burning emissions as their major source. Size distributions of fossil fuel derived n-alkane, PAHs and hopanes were found to be unimodal in most cases, peaking at 0.7–1.1 μm size. In contrast, plant wax derived n-alkanes presented a bimodal distribution with two peaks at the sizes of 0.7–1.1 μm and >4.7 μm in the summer mountain and spring marine samples. Among the three types of samples, geometric mean diameter (GMD of the organics in fine mode (<2.1 μm was found to be smallest (av. 0.63 μm in spring for the urban samples and largest (1.01 μm for the marine samples, whereas the GMD in coarse mode (≥2.1 μm was found to be smallest (3.48 μm for the marine aerosols and largest (4.04 μm for the urban aerosols. The fine mode GMDs of the urban and mountain samples were larger in winter than in spring and summer. Moreover, GMDs of 3- and 4-ring PAHs were larger than those of 5- and 6-ring PAHs in the three types of atmospheres. Such differences in GMDs can be interpreted by the repartitioning of organic compounds and the coagulation and hygroscopic growth of particles during a long-range transport from the inland continent to the marine area, as well as the difference in their sources among the three regions.

  3. Ring correlations in random networks.

    Science.gov (United States)

    Sadjadi, Mahdi; Thorpe, M F

    2016-12-01

    We examine the correlations between rings in random network glasses in two dimensions as a function of their separation. Initially, we use the topological separation (measured by the number of intervening rings), but this leads to pseudo-long-range correlations due to a lack of topological charge neutrality in the shells surrounding a central ring. This effect is associated with the noncircular nature of the shells. It is, therefore, necessary to use the geometrical distance between ring centers. Hence we find a generalization of the Aboav-Weaire law out to larger distances, with the correlations between rings decaying away when two rings are more than about three rings apart.

  4. PAHs in the Ices of Saturn's Satellites: Connections to the Solar Nebula and the Interstellar Medium

    Science.gov (United States)

    Cruikshank, Dale P.; Pendleton, Yvonne J.

    2015-01-01

    Aliphatic hydrocarbons and PAHs have been observed in the interstellar medium (e.g., Allamandola et al. 1985, Pendleton et al. 1994, Pendleton & Allamandola 2002, Tielens 2013, Kwok 2008, Chiar & Pendleton 2008) The inventory of organic material in the ISM was likely incorporated into the molecular cloud in which the solar nebula condensed, contributing to the feedstock for the formation of the Sun, major planets, and the smaller icy bodies in the region outside Neptune's orbit (transneptunian objects, or TNOs). Additional organic synthesis occurred in the solar nebula (Ciesla & Sandford 2012). Saturn's satellites Phoebe, Iapetus, and Hyperion open a window to the composition of one class of TNO as revealed by the near-infrared mapping spectrometer (VIMS) on the Cassini spacecraft at Saturn. Phoebe (mean diameter 213 km) is a former TNO now orbiting Saturn (Johnson & Lunine 2005). VIMS spectral maps of Phoebe's surface reveal a complex organic spectral signature consisting of prominent aromatic (CH) and aliphatic hydrocarbon (=CH2, -CH3) absorption bands (3.2-3.6 micrometers). Phoebe is the source of a huge debris ring encircling Saturn, and from which particles ((is) approximately 5-20 micrometers size) spiral inward toward Saturn (Verbiscer et al. 2009). They encounter Iapetus and Hyperion where they mix with and blanket the native H2O ice of those two bodies. Quantitative analysis of the hydrocarbon bands on Iapetus demonstrates that aromatic CH is approximately 10 times as abundant as aliphatic CH2+CH3, significantly exceeding the strength of the aromatic signature in interplanetary dust particles, comet particles, and in carbonaceous meteorites (Cruikshank et al. 2014). A similar excess of aromatics over aliphatics is seen in the qualitative analysis of Hyperion and Phoebe itself (Dalle Ore et al. 2012). The Iapetus aliphatic hydrocarbons show CH2/CH3 (is) approximately 4, which is larger than the value found in the diffuse ISM ((is) approximately 2

  5. Mapping Ring Particle Cooling across Saturn's Rings with Cassini CIRS

    Science.gov (United States)

    Brooks, Shawn M.; Spilker, L. J.; Edgington, S. G.; Pilorz, S. H.; Deau, E.

    2010-10-01

    Previous studies have shown that the rings' thermal inertia, a measure of their response to changes in the thermal environment, varies from ring to ring. Thermal inertia can provide insight into the physical structure of Saturn's ring particles and their regoliths. Low thermal inertia and quick temperature responses are suggestive of ring particles that have more porous or fluffy regoliths or that are riddled with cracks. Solid, coherent particles can be expected to have higher thermal inertias (Ferrari et al. 2005). Cassini's Composite Infrared Spectrometer has recorded millions of spectra of Saturn's rings since its arrival at Saturn in 2004 (personal communication, M. Segura). CIRS records far infrared radiation between 10 and 600 cm-1 (16.7 and 1000 µm) at focal plane 1 (FP1), which has a field of view of 3.9 mrad. Thermal emission from Saturn's rings peaks in this wavelength range. FP1 spectra can be used to infer ring temperatures. By tracking how ring temperatures vary, we can determine the thermal inertia of the rings. In this work we focus on CIRS observations of the shadowed portion of Saturn's rings. The thermal budget of the rings is dominated by the solar radiation absorbed by its constituent particles. When ring particles enter Saturn's shadow this source of energy is abruptly cut off. As a result, ring particles cool as they traverse Saturn's shadow. From these shadow observations we can create cooling curves at specific locations across the rings. We will show that the rings' cooling curves and thus their thermal inertia vary not only from ring to ring, but by location within the individual rings. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. Copyright 2010 California Institute of Technology. Government sponsorship acknowledged.

  6. PAH in Barbecued Meat from Restaurants and by Home-Grilling in Denmark

    DEFF Research Database (Denmark)

    Duedahl-Olesen, Lene; Meinert, L.; Aaslyng, M.

    2011-01-01

    Barbecuing or grilling is known to result in the formation of polycyclic aromatic hydrocarbons (PAH). Thirty home-grilled meat samples (beef, pork and chicken) and 86 commercial grilled meat samples (beef, pork, chicken, salmon, lamb and calf) were analyzed for 23 PAH including PAH 4 (benzo[a]pyr...

  7. Relation between PAH and black carbon contents in size fractions of Norwegian harbor sediments

    International Nuclear Information System (INIS)

    Oen, Amy M.P.; Cornelissen, Gerard; Breedveld, Gijs D.

    2006-01-01

    Distributions of total organic carbon (TOC), black carbon (BC), and polycyclic aromatic hydrocarbons (PAH) were investigated in different particle size fractions for four Norwegian harbor sediments. The total PAH (16-EPA) concentrations ranged from 2 to 113 mg/kg dry weight with the greatest fraction of PAH mass in the sand fraction for three of the four sediments. TOC contents ranged from 0.84% to 14.2% and BC contents from 0.085% to 1.7%. This corresponds to organic carbon (OC = TOC - BC) contents in the range of 0.81-14% and BC:TOC ratios of 1.3-18.1%. PAH isomer ratios suggested that the PAH in all four sediments were of pyrogenic origin. Furthermore, stronger correlations between PAH versus BC (r 2 = 0.85) than versus OC (r 2 = 0.15) were found. For all size fractions and bulk sediments, the PAH-to-BC ratios for the total PAHs were on average 6 ± 3 mg PAH/g BC. These results suggest that PAH distributions were dominated by the presence of BC, rather than OC. As sorption to BC is much stronger than sorption to OC, this may result in significantly lower dissolved concentrations of PAH than expected on the basis of organic carbon partitioning alone. - PAH contents correlated better with black carbon than organic carbon for four Norwegian harbor sediments

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

    International Nuclear Information System (INIS)

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

    2012-01-01

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

  9. 75 FR 8937 - Development of a Relative Potency Factor (RPF) Approach for Polycyclic Aromatic Hydrocarbon (PAH...

    Science.gov (United States)

    2010-02-26

    ... Relative Potency Factor (RPF) Approach for Polycyclic Aromatic Hydrocarbon (PAH) Mixtures AGENCY... Aromatic Hydrocarbon (PAH) Mixtures'' (EPA/635/R-08/012A). The draft document was prepared by the National... 27, 2010. The listening session on the draft document for PAH mixtures will be held on April 7, 2010...

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

    Science.gov (United States)

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

    2017-12-01

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous group of organic pollutants, some of which are known to be toxic, and/or carcinogenic to humans. The major source of these PAHs into the northern Gulf of Mexico (NGOM) are Mississippi River discharge, coastal erosion, atmospheric deposition, and numerous natural oil seeps and spills. In addition to these background source of PAHs, the Deepwater Horizon (DWH) oil spill in 2010 added 21,000 tons of PAHs into the NGOM water. In this study, we measured PAHs distribution and accumulation rates in coastal sediments near the Mississippi River mouth in 2011 and 2015 to understand the effect of DWH oil spill in PAHs accumulation in coastal sediments. Sediment cores were collected and sliced at 1 cm interval to measure PAHs concentration, and to estimate 210Pb-based sedimentation and the PAHs' accumulation rates. The results showed that the sediment deposition rates in this region varied between 0.5 to 0.9 cm/yr. The results also showed that the concentration of total PAHsPAH43) and their accumulation rates vary between 68 - 100 ng g-1 and 7 - 160 ng cm-2 yr-1, respectively. While the PAHs accumulation rate in coastal sediment varied over the years, there is no significant variation in PAHs accumulation rate before and after the DWH oil spill.

  11. On the evolution of vortex rings with swirl

    International Nuclear Information System (INIS)

    Naitoh, Takashi; Okura, Nobuyuki; Gotoh, Toshiyuki; Kato, Yusuke

    2014-01-01

    A laminar vortex ring with swirl, which has the meridional velocity component inside the vortex core, was experimentally generated by the brief fluid ejection from a rotating outlet. The evolution of the vortex ring was investigated with flow visualizations and particle image velocimetry measurements in order to find the influence of swirling flow in particular upon the transition to turbulence. Immediately after the formation of a vortex ring with swirl, a columnar strong vortex along the symmetric axis is observed in all cases of the present experiment. Then the characteristic fluid discharging from a vortex ring with swirl referred to as “peeling off” appears. The amount of discharging fluid due to the “peeling off” increases with the angular velocity of the rotating outlet. We conjectured that the mechanism generating the “peeling off” is related to the columnar strong vortex by close observations of the spatio-temporal development of the vorticity distribution and the cutting 3D images constructed from the successive cross sections of a vortex ring. While a laminar vortex ring without swirl may develop azimuthal waves around its circumference at some later time and the ring structure subsequently breaks, the swirling flow in a vortex ring core reduces the amplification rate of the azimuthal wavy deformation and preserved its ring structure. Then the traveling distance of a vortex ring can be extended using the swirl flow under certain conditions

  12. On the evolution of vortex rings with swirl

    Energy Technology Data Exchange (ETDEWEB)

    Naitoh, Takashi, E-mail: naitoh.takashi@nitech.ac.jp [Department of Engineering Physics, Electronics and Mechanics, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Okura, Nobuyuki, E-mail: ohkura@meijo-u.ac.jp [Department of Vehicle and Mechanical Engineering, Meijo University, 1-501 Shiogamaguchi Tempaku-ku, Nagoya 468-8502 (Japan); Gotoh, Toshiyuki, E-mail: gotoh.toshiyuki@nitech.ac.jp [Department of Scientific and Engineering Simulation, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Kato, Yusuke [Controller Business Unit Engineering Division 1, Engineering Department 3, Denso Wave Incorporated, 1 Yoshiike Kusagi Agui-cho, Chita-gun Aichi 470-2297 (Japan)

    2014-06-15

    A laminar vortex ring with swirl, which has the meridional velocity component inside the vortex core, was experimentally generated by the brief fluid ejection from a rotating outlet. The evolution of the vortex ring was investigated with flow visualizations and particle image velocimetry measurements in order to find the influence of swirling flow in particular upon the transition to turbulence. Immediately after the formation of a vortex ring with swirl, a columnar strong vortex along the symmetric axis is observed in all cases of the present experiment. Then the characteristic fluid discharging from a vortex ring with swirl referred to as “peeling off” appears. The amount of discharging fluid due to the “peeling off” increases with the angular velocity of the rotating outlet. We conjectured that the mechanism generating the “peeling off” is related to the columnar strong vortex by close observations of the spatio-temporal development of the vorticity distribution and the cutting 3D images constructed from the successive cross sections of a vortex ring. While a laminar vortex ring without swirl may develop azimuthal waves around its circumference at some later time and the ring structure subsequently breaks, the swirling flow in a vortex ring core reduces the amplification rate of the azimuthal wavy deformation and preserved its ring structure. Then the traveling distance of a vortex ring can be extended using the swirl flow under certain conditions.

  13. The Rings of Saturn

    Science.gov (United States)

    Cuzzi, J. N.; Filacchione, G.; Marouf, E. A.

    2018-03-01

    One could become an expert on Saturn's iconic rings pretty easily in the early 1970s, as very little was known about them beyond the distinction between the A, B, and C rings, and the Cassini Division or "gap" between rings A and B (Alexander, 1962; Bobrov, 1970). Water ice was discovered spectroscopically on the ring particle surfaces, and radar and microwave emission observations proved that the particles must be centimeters to meters in size, consisting primarily, not just superficially, of water ice (Pollack, 1975). While a 2:1 orbital resonance with Mimas had long been suspected of having something to do with the Cassini Division, computers of the time were unable to model the subtle dynamical effects that we now know to dominate ring structure. This innocent state of affairs was exploded by the Voyager 1 and 2 encounters in 1980 and 1981. Spectacular images revealed filigree structure and odd regional color variations, and exquisitely detailed radial profiles of fluctuating particle abundance were obtained from the first stellar and radio occultations, having resolution almost at the scale of single particles. Voyager-era understanding was reviewed by Cuzzi et al. (1984) and Esposito et al. (1984). While the Voyager data kept ring scientists busy for decades, planning which led to the monumentally successful NASA-ESA-ASI Cassini mission, which arrived in 2004, had been under way even before Voyager got to Saturn. A review of pre-Cassini knowledge of Saturn's Rings can be found in Orton et al. (2009). This chapter will build on recent topical and process-specific reviews that treat the gamut of ring phenomena and its underlying physics in considerable detail (Colwell et al., 2009; Cuzzi et al., 2009; Horányi et al., 2009; Schmidt et al., 2009; Esposito, 2010; Tiscareno, 2013b; Esposito, 2014). We will follow and extend the general organization of Cuzzi et al. (2010), the most recent general discussion of Saturn's rings. For brevity and the benefit of the

  14. BERKELEY: ALS ring

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1993-06-15

    Everybody at Lawrence Berkeley Laboratory's Center for Beam Physics is pleased with the rapid progress in commissioning LBL's Advanced Light Source (ALS) electron storage ring, the foundation for this third-generation synchrotron radiation facility. Designed for a maximum current of 400 mA, the ALS storage ring reached 407 mA just 24 days after storing the first beam on 16 March. ALS construction as a US Department of Energy (DOE) national user facility to provide high-brightness vacuum ultra-violet and soft x-ray radiation began in October 1987. One technical requirement marking project completion was to accumulate a 50-mA current in the storage ring. The ALS passed this milestone on 24 March, a week ahead of the official deadline. Once injected, the electron beam decays quasi-exponentially primarily because of interactions with residual gas molecules in the storage-ring vacuum chamber. Eventually, when the pressure in the vacuum chamber with beam decreases toward the expected operating level of 1 nano Torr, it will only be necessary to refill the storage ring at intervals of four to eight hours. At present the vacuum is improving rapidly as surfaces are irradiated (scrubbed) by the synchrotron radiation itself. At 100 mA, beam lifetime was about one hour (9 April)

  15. Compressible Vortex Ring

    Science.gov (United States)

    Elavarasan, Ramasamy; Arakeri, Jayawant; Krothapalli, Anjaneyulu

    1999-11-01

    The interaction of a high-speed vortex ring with a shock wave is one of the fundamental issues as it is a source of sound in supersonic jets. The complex flow field induced by the vortex alters the propagation of the shock wave greatly. In order to understand the process, a compressible vortex ring is studied in detail using Particle Image Velocimetry (PIV) and shadowgraphic techniques. The high-speed vortex ring is generated from a shock tube and the shock wave, which precedes the vortex, is reflected back by a plate and made to interact with the vortex. The shadowgraph images indicate that the reflected shock front is influenced by the non-uniform flow induced by the vortex and is decelerated while passing through the vortex. It appears that after the interaction the shock is "split" into two. The PIV measurements provided clear picture about the evolution of the vortex at different time interval. The centerline velocity traces show the maximum velocity to be around 350 m/s. The velocity field, unlike in incompressible rings, contains contributions from both the shock and the vortex ring. The velocity distribution across the vortex core, core diameter and circulation are also calculated from the PIV data.

  16. BERKELEY: ALS ring

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    Everybody at Lawrence Berkeley Laboratory's Center for Beam Physics is pleased with the rapid progress in commissioning LBL's Advanced Light Source (ALS) electron storage ring, the foundation for this third-generation synchrotron radiation facility. Designed for a maximum current of 400 mA, the ALS storage ring reached 407 mA just 24 days after storing the first beam on 16 March. ALS construction as a US Department of Energy (DOE) national user facility to provide high-brightness vacuum ultra-violet and soft x-ray radiation began in October 1987. One technical requirement marking project completion was to accumulate a 50-mA current in the storage ring. The ALS passed this milestone on 24 March, a week ahead of the official deadline. Once injected, the electron beam decays quasi-exponentially primarily because of interactions with residual gas molecules in the storage-ring vacuum chamber. Eventually, when the pressure in the vacuum chamber with beam decreases toward the expected operating level of 1 nano Torr, it will only be necessary to refill the storage ring at intervals of four to eight hours. At present the vacuum is improving rapidly as surfaces are irradiated (scrubbed) by the synchrotron radiation itself. At 100 mA, beam lifetime was about one hour (9 April)

  17. Urinary concentrations of PAH and VOC metabolites in marijuana users.

    Science.gov (United States)

    Wei, Binnian; Alwis, K Udeni; Li, Zheng; Wang, Lanqing; Valentin-Blasini, Liza; Sosnoff, Connie S; Xia, Yang; Conway, Kevin P; Blount, Benjamin C

    2016-03-01

    Marijuana is seeing increased therapeutic use, and is the world's third most-popular recreational drug following alcohol and tobacco. This widening use poses increased exposure to potentially toxic combustion by-products from marijuana smoke and the potential for public health concerns. To compare urinary metabolites of polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs) among self-reported recent marijuana users and nonusers, while accounting for tobacco smoke exposure. Measurements of PAH and VOC metabolites in urine samples were combined with questionnaire data collected from participants in the National Health and Nutrition Examination Surveys (NHANES) from 2005 to 2012 in order to categorize participants (≥18years) into exclusive recent marijuana users and nonusers. Adjusted geometric means (GMs) of urinary concentrations were computed for these groups using multiple regression analyses to adjust for potential confounders. Adjusted GMs of many individual monohydroxy PAHs (OH-PAHs) were significantly higher in recent marijuana users than in nonusers (pmarijuana users than in nonusers. We found elevated levels of biomarkers for potentially harmful chemicals among self-identified, recent marijuana users compared with nonusers. These findings suggest that further studies are needed to evaluate the potential health risks to humans from the exposure to these agents when smoking marijuana. Published by Elsevier Ltd.

  18. Investigating the temporal trends in PAH, PCB and OCP ...

    African Journals Online (AJOL)

    2013-05-09

    May 9, 2013 ... mation on application of passive sampling in South Africa is available in the literature. This study was ..... molecular weight PAHs in the current study were on average up to 2 orders of magnitude lower ..... VAN REI WF (1987) The Hartbeespoort dam – a magnet to millions? In: Thornton JA and Walmsley RD ...

  19. Bioremediation of polyaromatic hydrocarbons (PAHs using rhizosphere technology

    Directory of Open Access Journals (Sweden)

    Sandeep Bisht

    2015-03-01

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

  20. Cosmic PAHs: from infrared astronomy to laboratory astrophysics

    Science.gov (United States)

    Joblin, Christine

    2017-06-01

    Astronomers consider polycyclic aromatic hydrocarbons (PAHs) to be the smallest dust particles and they use their infrared emission features, the aromatic infrared bands (AIBs), as a diagnostic of physical conditions in regions of star formation from the small scales of protoplanetary disks to the large scales of galaxies. This topic has to face several obstacles. One is the lack of identification of specific PAH species. Another one is that the AIB features carry not only information on the chemical diversity of species but also on photophysical processes involved in the relaxation of PAHs after having been energized by the absorption of UV photons from stars. In this presentation, I will discuss how we can progress in the analysis of the observed AIB spectrum by addressing both the photophysics of isolated PAHs and the formation and evolution of these molecules in cosmic environments. This is achieved by the combination of astronomical models with detailed investigation of molecular processes. The study of these processes has stimulated the development of dedicated laboratory setups and theoretical simulations at the forefront of molecular physics. I will more specifically present the opening given by ERC Synergy project Nanocosmos and the perspectives with the coming James Webb telescope.

  1. MULTIMEDIA CONCENTRATIONS OF PAH IN SEVERAL DAY CARE CENTERS

    Science.gov (United States)

    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...

  2. Small phosphatidate phosphatase (TtPAH2) of Tetrahymena ...

    Indian Academy of Sciences (India)

    Anoop Narayana Pillai

    2017-10-03

    Oct 3, 2017 ... There was no significant difference (indicated as 'ns') in the number of lipid droplets as analysed by Kruskal-Wallis test. (p \\0.01). .... and Goodman JM 2011 The yeast lipin orthologue Pah1p is ... gamma transcriptional activity.

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

    DEFF Research Database (Denmark)

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

    2015-01-01

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

  4. Polycyclic aromatic hydrocarbons and PAH-related DNA adducts.

    Science.gov (United States)

    Ewa, Błaszczyk; Danuta, Mielżyńska-Švach

    2017-08-01

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

  5. PAH desorption from river floodplain soils using supercritical fluid extraction

    Czech Academy of Sciences Publication Activity Database

    Yang, Y.; Cajthaml, Tomáš; Hofmann, T.

    2008-01-01

    Roč. 156, č. 3 (2008), s. 745-752 ISSN 0269-7491 R&D Projects: GA MŠk 2B06156 Institutional research plan: CEZ:AV0Z50200510 Keywords : pahs * slow desorption * carbonaceous materials Subject RIV: EE - Microbiology, Virology Impact factor: 3.135, year: 2008

  6. Bioremediation of polyaromatic hydrocarbons (PAHs) using rhizosphere technology

    Science.gov (United States)

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

    2015-01-01

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

  7. Improving bioremediation of PAH contaminated soils by thermal pretreatment

    NARCIS (Netherlands)

    Bonten, L.

    2001-01-01

    Numerous sites and large volumes of sediments in the Netherlands are contaminated with polycyclic aromatic hydrocarbons (PAH), which are of great concern because of their

  8. Effect of smoking on Polycyclic Aromatic Hydrocarbons (PAHS ...

    African Journals Online (AJOL)

    The effects of smoking on proximate composition, energy values and concentrations of polycyclic aromatic hydrocarbons (PAHs) were studied in raw and smoked samples of catfish (Clarias gariepinus) and tilapia (Oreochromis niloticus). Crude protein was higher in the tilapia sample for both raw and smoked samples.

  9. PAHs, OCPs and PCBs in sediments from three catchments in ...

    African Journals Online (AJOL)

    Based on the comparison of chemical concentrations to international sediment quality guidelines, PAH, OCP and PCB concentrations in most sediment samples posed a low risk to sediment-dwelling organisms. However, in some instances the risk was moderate or high. It is recommended that these compounds be ...

  10. PAHs molecules and heating of the interstellar gas

    Science.gov (United States)

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

    1989-01-01

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

  11. PAH features within few hundred parsecs of active galactic nuclei

    Science.gov (United States)

    Jensen, J. J.; Hönig, S. F.; Rakshit, S.; Alonso-Herrero, A.; Asmus, D.; Gandhi, P.; Kishimoto, M.; Smette, A.; Tristram, K. R. W.

    2017-09-01

    Spectral features from polycyclic aromatic hydrocarbon (PAH) molecules observed in the mid-infrared (mid-IR) range are typically used to infer the amount of recent and ongoing star formation on kiloparsec scales around active galactic nuclei (AGN) where more traditional methods fail. This method assumes that the observed PAH features are excited predominantly by star formation. With current ground-based telescopes and the upcoming James Webb Space Telescope, much smaller spatial scales can be probed and we aim at testing if this assumption still holds in the range of few tens to few hundreds of parsecs. For that, we spatially map the emitted 11.3 μm PAH surface flux as a function of distance from 0.4-4 arcsec from the centre in 28 nearby AGN using ground-based high-angular-resolution mid-IR spectroscopy. We detect and extract the 11.3 μm PAH feature in 13 AGN. The fluxes within each aperture are scaled to a luminosity-normalized distance from the nucleus to be able to compare intrinsic spatial scales of AGN radiation spanning about two orders of magnitude in luminosity. For this, we establish an empirical relation between the absorption-corrected X-ray luminosity and the sublimation radius in these sources. Once normalized, the radial profiles of the emitted PAH surface flux show similar radial slopes, with a power-law index of approximately -1.1, and similar absolute values, consistent within a factor of a few of each other as expected from the uncertainty in the intrinsic scale estimate. We interpret this as evidence that the profiles are caused by a common compact central physical process, either the AGN itself or circumnuclear star formation linked in strength to the AGN power. A photoionization-based model of an AGN exciting dense clouds in its environment can reproduce the observed radial slope and confirms that the AGN radiation field is strong enough to explain the observed PAH surface fluxes within ∼10-500 pc of the nucleus. Our results advice caution

  12. Spatial correlation analysis of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) in sediments between Taihu Lake and its tributary rivers.

    Science.gov (United States)

    Zhao, Zhonghua; Jiang, Yu; Li, Qianyu; Cai, Yongjiu; Yin, Hongbin; Zhang, Lu; Zhang, Jin

    2017-08-01

    The residues of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) in surface sediments from Taihu Lake basin (THB) and Taihu Lake body (THL) were investigated. Higher concentrations of both PAHs and OCPs were observed for THB than THL. The concentrations of PAHs ranged from 12.1 to 2281.1ngg -1 dw for THB and from 11.4 to 209.9ngg -1 dw for THL, while OCPs ranged from 16.3 to 96.9ngg -1 dw and from 16.8 to 61.9ngg -1 dw for THB and THL, respectively. Spatial distribution of PAHs and OCPs showed a high correspondence with the land use of THB and surrounding anthropogenic activity. Additionally, the Kriging interpolation plots demonstrated that the major upper reaches were more polluted than the lower reaches, indicating the transport of pollutants with the water flow direction. The organic matter contents were responsible for OCP distribution other than PAHs due to the biodegradation capacity difference of chemicals. Similar compositions of pollutants were observed with 3- and 4-ringed PAHs accounting for a total of 78.3% for THB and 85.8% for THL, respectively. HCHs and DDTs were predominant OCPs, which contributed to 31.8% and 21.7% for THB, and 33.6% and 21.9% for THL, respectively. The isomeric and parent substance/metabolite ratios implied fresh inputs of DDTs and chlordanes, while HCHs and endosulfans were mainly from old usage. PAH source identification performed by diagnostic ratios demonstrated the mixed sources of petrogenic and pyrogenic ones dominated by grass, wood and coal combustion. Furthermore, the hazard quotient (HQ) based on the consensus-based sediment quality guidelines (SQGs) was used to evaluate the ecological risks of sediments. Although no frequently adverse effects were observed, potential ecological risks induced by Ant, BaA, γ-HCH, dieldrin, p,p'-DDT and chlordanes should also be paid attention to considering the continuous inputs of such pollutants. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Almost ring theory

    CERN Document Server

    2003-01-01

    This book develops thorough and complete foundations for the method of almost etale extensions, which is at the basis of Faltings' approach to p-adic Hodge theory. The central notion is that of an "almost ring". Almost rings are the commutative unitary monoids in a tensor category obtained as a quotient V-Mod/S of the category V-Mod of modules over a fixed ring V; the subcategory S consists of all modules annihilated by a fixed ideal m of V, satisfying certain natural conditions. The reader is assumed to be familiar with general categorical notions, some basic commutative algebra and some advanced homological algebra (derived categories, simplicial methods). Apart from these general prerequisites, the text is as self-contained as possible. One novel feature of the book - compared with Faltings' earlier treatment - is the systematic exploitation of the cotangent complex, especially for the study of deformations of almost algebras.

  14. Characteristics of particulate PAHs during a typical haze episode in Guangzhou, China

    Science.gov (United States)

    Tan, Jihua; Guo, Songjun; Ma, Yongliang; Duan, Jingchun; Cheng, Yuan; He, Kebin; Yang, Fumo

    2011-10-01

    The concentrations of polycyclic aromatic hydrocarbons (PAHs) in PM 2.5 and TSP were measured in Guangzhou during a typical haze episode. This episode included NH (non-haze, 3 days), HFN (haze when air masses from north and northeast, 6 days) and HFS (haze when air masses from south, 4 days). The air quality in HFN was much worse than that in NH and HFS. The total average concentrations of PAHs in PM 2.5 were 13.25 ng m -3, 59.82 ng m -3 and 13.09 ng m -3 in NH, HFN and HFS, respectively. It indicated PAH pollution had been substantially aggravated by HFN. PAHs(5 + 6) were the most abundant compounds in HFN and HFS, which accounted for 55-75% of total concentration of PAHs, while PAHs(3 + 4) were the most abundant compounds in NH, which accounted for 54-67% of total concentration of PAHs. TEF (Toxic Equivalency Factors)-adjusted concentrations of 13 particulate PAHs were very high in HFN, indicating high health risks to humans for PAH exposure in HFN. The characteristic ratios of PAHs indicated coal combustion and traffic emission were the major contributors to PAHs in HFN and HFS. The concentrations of particulate PAHs in haze episode were strongly affected by wind speed and wind direction. PAHs in NH could be from long-range transport with high north wind speed, while local emission could be the main contributor of particle-associated PAHs in HFN. The transport speed of air masses was found to play an important role on PAH concentrations.

  15. Diurnal variations of ambient particulate wood burning emissions and their contribution to the concentration of Polycyclic Aromatic Hydrocarbons (PAHs) in Seiffen, Germany

    Science.gov (United States)

    Poulain, L.; Iinuma, Y.; Müller, K.; Birmili, W.; Weinhold, K.; Brüggemann, E.; Gnauk, T.; Hausmann, A.; Löschau, G.; Wiedensohler, A.; Herrmann, H.

    2011-12-01

    Residential wood burning is becoming an increasingly important cause of air quality problems since it has become a popular source of alternative energy to fossil fuel. In order to characterize the contribution of residential wood burning to local particle pollution, a field campaign was organized at the village of Seiffen (Saxony, Germany). During this campaign, an Aerosol Mass Spectrometer (AMS) was deployed in parallel to a PM1 high volume filter sampler. The AMS mass spectra were analyzed using Positive Matrix Factorization (PMF) to obtain detailed information about the organic aerosol (OA). Biomass-burning organic aerosol (BBOA), Hydrocarbon-like organic aerosol (HOA), and Oxygenated Organic Aerosol (OOA) were identified and represented 20%, 17% and 62% of total OA, respectively. Additionally, Polycyclic Aromatic Hydrocarbons (PAH) were measured by the AMS with an average concentration of 10 ng m-3 and short term events of extremely high PAH concentration (up to 500 ng m-3) compared to the mean PAH value were observed during the whole measurement period. A comparison with the results from PM1 filter samples showed that the BBOA factor and the AMS PAH are good indicators of the total concentration of the different monosaccharide anhydrides and PAH measured on the filter samples. Based on its low correlation with CO and the low car traffic, the HOA factor was considered to be related to residential heating using liquid fuel. An influence of the time of the week (week vs. weekend) on the diurnal profiles of the different OA components was observed. The weekdays were characterized by two maxima; a first one early in the morning and a stronger one in the evening. During the weekend days, the different OA components principally reached only one maximum in the afternoon. Finally, the PAH emitted directly from residential wood combustion was estimated to represent 1.5% of the total mass of the BBOA factor and around 62% of the total PAH concentration measured at

  16. Diurnal variations of ambient particulate wood burning emissions and their contribution to the concentration of Polycyclic Aromatic Hydrocarbons (PAHs in Seiffen, Germany

    Directory of Open Access Journals (Sweden)

    L. Poulain

    2011-12-01

    Full Text Available Residential wood burning is becoming an increasingly important cause of air quality problems since it has become a popular source of alternative energy to fossil fuel. In order to characterize the contribution of residential wood burning to local particle pollution, a field campaign was organized at the village of Seiffen (Saxony, Germany. During this campaign, an Aerosol Mass Spectrometer (AMS was deployed in parallel to a PM1 high volume filter sampler. The AMS mass spectra were analyzed using Positive Matrix Factorization (PMF to obtain detailed information about the organic aerosol (OA. Biomass-burning organic aerosol (BBOA, Hydrocarbon-like organic aerosol (HOA, and Oxygenated Organic Aerosol (OOA were identified and represented 20%, 17% and 62% of total OA, respectively. Additionally, Polycyclic Aromatic Hydrocarbons (PAH were measured by the AMS with an average concentration of 10 ng m−3 and short term events of extremely high PAH concentration (up to 500 ng m−3 compared to the mean PAH value were observed during the whole measurement period. A comparison with the results from PM1 filter samples showed that the BBOA factor and the AMS PAH are good indicators of the total concentration of the different monosaccharide anhydrides and PAH measured on the filter samples. Based on its low correlation with CO and the low car traffic, the HOA factor was considered to be related to residential heating using liquid fuel. An influence of the time of the week (week vs. weekend on the diurnal profiles of the different OA components was observed. The weekdays were characterized by two maxima; a first one early in the morning and a stronger one in the evening. During the weekend days, the different OA components principally reached only one maximum in the afternoon. Finally, the PAH emitted directly from residential wood combustion was estimated to represent 1.5% of the total mass of the BBOA factor and

  17. Compact electron storage rings

    International Nuclear Information System (INIS)

    Williams, G.P.

    1987-01-01

    There have been many recent developments in the area of compact storage rings. Such rings would have critical wavelengths of typically 10 A, achieved with beam energies of several hundreds of MeV and superconducting dipole fields of around 5 Tesla. Although the primary motivation for progress in this area is that of commercial x-ray lithography, such sources might be an attractive source for college campuses to operate. They would be useful for many programs in materials science, solid state, x-ray microscopy and other biological areas. We discuss the properties of such sources and review developments around the world, primarily in the USA, japan and W. Germany

  18. The covariant chiral ring

    Energy Technology Data Exchange (ETDEWEB)

    Bourget, Antoine; Troost, Jan [Laboratoire de Physique Théorique, École Normale Supérieure, 24 rue Lhomond, 75005 Paris (France)

    2016-03-23

    We construct a covariant generating function for the spectrum of chiral primaries of symmetric orbifold conformal field theories with N=(4,4) supersymmetry in two dimensions. For seed target spaces K3 and T{sup 4}, the generating functions capture the SO(21) and SO(5) representation theoretic content of the chiral ring respectively. Via string dualities, we relate the transformation properties of the chiral ring under these isometries of the moduli space to the Lorentz covariance of perturbative string partition functions in flat space.

  19. Vortex and source rings

    DEFF Research Database (Denmark)

    Branlard, Emmanuel Simon Pierre

    2017-01-01

    The velocity field, vector potential and velocity gradient of a vortex ring is derived in this chapter. The Biot-Savart law for the vector potential and velocity is expressed in a first section. Then, the flow is derived at specific locations: on the axis, near the axis and in the far field where...... the analogy to a doublet field is made. The following section derive the value of the vector potential and velocity field in the full domain. The expression for the velocity gradient is also provided since it may be relevant in a simulation with vortex particles and vortex rings. Most of this chapter...

  20. The Saturnian rings

    International Nuclear Information System (INIS)

    Alfven, H.

    1975-09-01

    The structure of the Saturnian rings is traditionally believed to be due to resonances caused by Mimas (and possibly other satellites). It is shown that both theoretical and observational evidence rule out this interpretation. The increased observational accuracy on one hand and the increased understanding of the cosmogonic processes on the other makes it possible to explain the structure of the ring system as a product of condensation from a partially corotating plasma. In certain respects the agreement between theory and observations is about 1%. (Auth.)

  1. RINGED ACCRETION DISKS: INSTABILITIES

    Energy Technology Data Exchange (ETDEWEB)

    Pugliese, D.; Stuchlík, Z., E-mail: d.pugliese.physics@gmail.com, E-mail: zdenek.stuchlik@physics.cz [Institute of Physics and Research Centre of Theoretical Physics and Astrophysics, Faculty of Philosophy and Science, Silesian University in Opava, Bezručovo náměstí 13, CZ-74601 Opava (Czech Republic)

    2016-04-01

    We analyze the possibility that several instability points may be formed, due to the Paczyński mechanism of violation of mechanical equilibrium, in the orbiting matter around a supermassive Kerr black hole. We consider a recently proposed model of a ringed accretion disk, made up by several tori (rings) that can be corotating or counter-rotating relative to the Kerr attractor due to the history of the accretion process. Each torus is governed by the general relativistic hydrodynamic Boyer condition of equilibrium configurations of rotating perfect fluids. We prove that the number of the instability points is generally limited and depends on the dimensionless spin of the rotating attractor.

  2. Effects of chemical oxidation on sorption and desorption of PAHs in typical Chinese soils

    International Nuclear Information System (INIS)

    Chen Wei; Hou Lei; Luo Xiaoli; Zhu Lingyan

    2009-01-01

    In situ chemical oxidation is a commonly applied soil and groundwater remediation technology, but can have significant effects on soil properties, which in turn might affect fate and transport of organic contaminants. In this study, it was found that oxidation treatment resulted mainly in breakdown of soil organic matter (SOM) components. Sorption of naphthalene and phenanthrene to the original soils and the KMnO 4 -treated soils was linear, indicating that hydrophobic partitioning to SOM was the predominant mechanism for sorption. Desorption from the original and treated soils was highly resistant, and was well modeled with a biphasic desorption model. Desorption of residual naphthalene after treating naphthalene-contaminated soils with different doses of KMnO 4 also followed the biphasic desorption model very well. It appears that neither changes of soil properties caused by chemical oxidation nor direct chemical oxidation of contaminated soils had a noticeable effect on the nature of PAH-SOM interactions. - Chemical oxidation of soils had little effect on the mechanisms controlling sorption and desorption of PAHs.

  3. Exposure to polycyclic aromatic hydrocarbons (PAHs), mutagenic aldehydes and particulate matter during pan frying of beefsteak.

    Science.gov (United States)

    Sjaastad, Ann Kristin; Jørgensen, Rikke Bramming; Svendsen, Kristin

    2010-04-01

    Cooking with gas or electric stoves produces fumes, especially during frying, that contain a range of harmful and potentially mutagenic compounds as well as high levels of fine and ultrafine particles. The aim of this study was to see if polycyclic aromatic hydrocarbons (PAHs) and higher mutagenic aldehydes which were collected in the breathing zone of the cook, could be detected in fumes from the frying of beefsteak. The frying was performed in a model kitchen in conditions similar to those in a Western European restaurant kitchen. The levels of PAHs (16 EPA standard) and higher aldehydes (trans,trans-2,4-decadienal, 2,4-decadienal, trans-trans-2,4-nonadienal, trans-2-decenal, cis-2-decenal, trans-2-undecenal, 2-undecenal) were measured during frying on an electric or gas stove with margarine or soya bean oil as the frying fat. The number concentration of particles electric stove causes increased occupational exposure to some of the components in cooking fumes which may cause adverse health effects.

  4. Ring rolling process simulation for geometry optimization

    Science.gov (United States)

    Franchi, Rodolfo; Del Prete, Antonio; Donatiello, Iolanda; Calabrese, Maurizio

    2017-10-01

    Ring Rolling is a complex hot forming process where different rolls are involved in the production of seamless rings. Since each roll must be independently controlled, different speed laws must be set; usually, in the industrial environment, a milling curve is introduced to monitor the shape of the workpiece during the deformation in order to ensure the correct ring production. In the present paper a ring rolling process has been studied and optimized in order to obtain anular components to be used in aerospace applications. In particular, the influence of process input parameters (feed rate of the mandrel and angular speed of main roll) on geometrical features of the final ring has been evaluated. For this purpose, a three-dimensional finite element model for HRR (Hot Ring Rolling) has been implemented in SFTC DEFORM V11. The FEM model has been used to formulate a proper optimization problem. The optimization procedure has been implemented in the commercial software DS ISight in order to find the combination of process parameters which allows to minimize the percentage error of each obtained dimension with respect to its nominal value. The software allows to find the relationship between input and output parameters applying Response Surface Methodology (RSM), by using the exact values of output parameters in the control points of the design space explored through FEM simulation. Once this relationship is known, the values of the output parameters can be calculated for each combination of the input parameters. After the calculation of the response surfaces for the selected output parameters, an optimization procedure based on Genetic Algorithms has been applied. At the end, the error between each obtained dimension and its nominal value has been minimized. The constraints imposed were the maximum values of standard deviations of the dimensions obtained for the final ring.

  5. Polycyclic aromatic hydrocarbons (PAHs) in Austin sediments after a ban on pavement sealers

    Energy Technology Data Exchange (ETDEWEB)

    DeMott, R.P.; Gauthier, T.D.; Wiersema, J.M.; Crenson, G. [ENVIRON International, Tampa, FL (USA)

    2010-07-01

    Polycyclic aromatic hydrocarbon (PAH) concentrations were measured in stream sediments collected before and after a municipal ban on the use of coal-tar-based pavement sealers in Austin, Texas. Samples were collected in October 2005, prior to the ban, and again in April, 2008, approximately 2 years after the ban. Differences in total PAH concentrations between samples collected before and after the ban show no net change in PAH levels in Austin stream sediments. Results of hydrocarbon fingerprinting reveal subtle differences in PAH profiles that appear to reflect the effects of weathering rather than a change in PAH sources.

  6. THE FAR-INFRARED EMISSION FROM THE Mg+-PAH SPECIES

    International Nuclear Information System (INIS)

    Bauschlicher, Charles W. Jr.; Ricca, Alessandra

    2009-01-01

    The far-infrared (FIR) spectra of several Mg + -PAH species are studied using density functional theory. The Mg + -PAH stretching mode, regardless of the polycyclic aromatic hydrocarbon (PAH) species, carries a reasonable intensity and tends to fall in a narrow range near 40 μm. Because the bands tend to fall at very similar frequencies, the average spectra of several Mg + -PAH species produce a broadband with an intensity that is about 20% of the well known C-H out-of-plane bending mode. In contrast, an average of seven large compact pure PAHs has no FIR bands that carry any significant intensity.

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

    Science.gov (United States)

    Bansal, Vasudha; Kim, Ki-Hyun

    2015-11-01

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

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

    Science.gov (United States)

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

    2015-01-01

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

  9. Emission characterization and δ"1"3C values of parent PAHs and nitro-PAHs in size-segregated particulate matters from coal-fired power plants

    International Nuclear Information System (INIS)

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

    2016-01-01

    Highlights: • pPAHs and NPAHs were strongly associated with PM_1_–_2_._5 and PM_1 compared with PM_2_._5_–_1_0. • Combustion conditions and WFGD showed typical effects on PAH level and profile. • Diagnostic ratio of PAH was to indicative of emission sources to a certain degree. • δ"1"3C values of PAHs were useful for differentiating coal combustion source. • δ"1"3C values of PAHs were unable to differentiate coal-processing sources. - Abstract: The objective of this study was to characterize parent polycyclic aromatic hydrocarbons (pPAHs) and their nitrated derivatives (NPAHs) in coarse (PM_2_._5_–_1_0), intermediate (PM_1_–_2_._5) and fine (PM_1) particulate matters emitted from coal-fired power plants (CFPPs) in Huainan, China. The diagnostic ratios and the stable carbon isotopic approaches to characterize individual PAHs were applied in order to develop robust tools for tracing the origins of PAHs in different size-segregated particular matters (PMs) emitted CFPP coal combustion. The concentrations of PAH compounds in flue gas emissions varied greatly, depending on boiler types, operation and air pollution control device (APCD) conditions. Both pPAHs and NPAHs were strongly enriched in PM_1_–_2_._5 and PM_1. In contrary to low molecular weight (LMW) PAHs, high molecular weight (HMW) PAHs were more enriched in finer PMs. The PAH diagnostic ratios in size-segregated PMs are small at most cases, highlighting their potential application in tracing CFPP emitted PAHs attached to different sizes of PMs. Yet, substantial uncertainty still exists to directly apply PAH diagnostic ratios as emission tracers. Although the stable carbon isotopic composition of PAH molecular was useful in differentiating coal combustion emissions from other sources such as biomass combustion and vehicular exhausts, it was not feasible to differentiate isotopic fractionation processes such as low-temperature carbonization, high-temperature carbonization, gasification and

  10. Emission characterization and δ{sup 13}C values of parent PAHs and nitro-PAHs in size-segregated particulate matters from coal-fired power plants

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ruwei [CAS Key Laboratory of Crust-Mantle Materials and the Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026 (China); State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, The Chinese Academy of Sciences, Xi’an 710075 Shaanxi (China); Yousaf, Balal; Sun, Ruoyu [CAS Key Laboratory of Crust-Mantle Materials and the Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026 (China); Zhang, Hong [Anhui Department of Environmental Protection, Anhui Academy of Environmental Science, Hefei 230071 (China); Zhang, Jiamei [CAS Key Laboratory of Crust-Mantle Materials and the Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026 (China); Liu, Guijian, E-mail: lgj@ustc.edu.cn [CAS Key Laboratory of Crust-Mantle Materials and the Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026 (China); State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, The Chinese Academy of Sciences, Xi’an 710075 Shaanxi (China)

    2016-11-15

    Highlights: • pPAHs and NPAHs were strongly associated with PM{sub 1–2.5} and PM{sub 1} compared with PM{sub 2.5–10}. • Combustion conditions and WFGD showed typical effects on PAH level and profile. • Diagnostic ratio of PAH was to indicative of emission sources to a certain degree. • δ{sup 13}C values of PAHs were useful for differentiating coal combustion source. • δ{sup 13}C values of PAHs were unable to differentiate coal-processing sources. - Abstract: The objective of this study was to characterize parent polycyclic aromatic hydrocarbons (pPAHs) and their nitrated derivatives (NPAHs) in coarse (PM{sub 2.5–10}), intermediate (PM{sub 1–2.5}) and fine (PM{sub 1}) particulate matters emitted from coal-fired power plants (CFPPs) in Huainan, China. The diagnostic ratios and the stable carbon isotopic approaches to characterize individual PAHs were applied in order to develop robust tools for tracing the origins of PAHs in different size-segregated particular matters (PMs) emitted CFPP coal combustion. The concentrations of PAH compounds in flue gas emissions varied greatly, depending on boiler types, operation and air pollution control device (APCD) conditions. Both pPAHs and NPAHs were strongly enriched in PM{sub 1–2.5} and PM{sub 1}. In contrary to low molecular weight (LMW) PAHs, high molecular weight (HMW) PAHs were more enriched in finer PMs. The PAH diagnostic ratios in size-segregated PMs are small at most cases, highlighting their potential application in tracing CFPP emitted PAHs attached to different sizes of PMs. Yet, substantial uncertainty still exists to directly apply PAH diagnostic ratios as emission tracers. Although the stable carbon isotopic composition of PAH molecular was useful in differentiating coal combustion emissions from other sources such as biomass combustion and vehicular exhausts, it was not feasible to differentiate isotopic fractionation processes such as low-temperature carbonization, high

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

    Science.gov (United States)

    Košnář, Zdeněk; Mercl, Filip; Tlustoš, Pavel

    2018-05-30

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

  12. Polycyclic Aromatic Hydrocarbons (PAHs) and their Bioaccessibility in Meat: a Tool for Assessing Human Cancer Risk.

    Science.gov (United States)

    Hamidi, Elliyana Nadia; Hajeb, Parvaneh; Selamat, Jinap; Abdull Razis, Ahmad Faizal

    2016-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are primarily formed as a result of thermal treatment of food, especially barbecuing or grilling. Contamination by PAHs is due to generation by direct pyrolysis of food nutrients and deposition from smoke produced through incomplete combustion of thermal agents. PAHs are ubiquitous compounds, well-known to be carcinogenic, which can reach the food in different ways. As an important human exposure pathway of contaminants, dietary intake of PAHs is of increasing concern for assessing cancer risk in the human body. In addition, the risks associated with consumption of barbecued meat may increase if consumers use cooking practices that enhance the concentrations of contaminants and their bioaccessibility. Since total PAHs always overestimate the actual amount that is available for absorption by the body, bioaccessibility of PAHs is to be preferred. Bioaccessibility of PAHs in food is the fraction of PAHs mobilized from food matrices during gastrointestinal digestion. An in vitro human digestion model was chosen for assessing the bioaccessibility of PAHs in food as it offers a simple, rapid, low cost alternative to human and animal studies; providing insights which may not be achievable in in vivo studies. Thus, this review aimed not only to provide an overview of general aspects of PAHs such as the formation, carcinogenicity, sources, occurrence, and factors affecting PAH concentrations, but also to enhance understanding of bioaccessibility assessment using an in vitro digestion model.

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

    International Nuclear Information System (INIS)

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

    2011-01-01

    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) x polynuclear aromatic hydrocarbons (PAHs) x 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.

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

    International Nuclear Information System (INIS)

    Roscales, Jose L.; Gonzalez-Solis, Jacob; Calabuig, Pascual; Jimenez, Begona

    2011-01-01

    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. - Highlights: → PAHs in pelagic seabirds show specific inter-species patterns related to trophic ecology. → Geographic origin shows a minor effect over PAH levels in pelagic seabirds. → Pelagic seabirds seem to be poor indicators of chronic PAH levels. - PAH levels in Atlantic and Mediterranean pelagic seabirds show specific inter-species patterns related to trophic ecology but a minor influence of their geographic origin.

  15. Mass balance-based regression modeling of PAHs accumulation in urban soils, role of urban development

    International Nuclear Information System (INIS)

    Peng, Chi; Wang, Meie; Chen, Weiping; Chang, Andrew C.

    2015-01-01

    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. - Highlights: • Introduced a mass balance model for soil PAHs accumulation with urbanization. • Reconstructed the historical data of PAH accumulation in soil of Beijing, China. • The soil PAH concentrations would be doubled in the following 40 years. • The composition of PAH emissions were shifting to light PAH species. - Introduced a regression modeling approach to predict the changes of PAH concentrations in urban soil

  16. Watershed-scale modeling on the fate and transport of polycyclic aromatic hydrocarbons (PAHs)

    International Nuclear Information System (INIS)

    Ligaray, Mayzonee; Baek, Sang Soo; Kwon, Hye-Ok; Choi, Sung-Deuk; Cho, Kyung Hwa

    2016-01-01

    PAHs are potentially carcinogenic substances that are persistent in the environment. Increasing concentrations of PAHs were observed due to rapid urbanization, thus; monitoring PAHs concentrations is necessary. However, it is expensive to conduct intensive monitoring activities of a large number of PAHs. This study addressed this issue by developing a multimedia model coupled with a hydrological model (i.e., Soil and Water Assessment Tool (SWAT)) for Taehwa River (TR) watershed in Ulsan, the industrial capital of South Korea. The hydrologic module of the SWAT was calibrated, and further used to simulate the fate and transport of PAHs in soil and waterbody. The model demonstrated that the temporal or seasonal variation of PAHs in soil and waterbody can be well reproduced. Meanwhile, the spatial distribution of PAHs showed that urban areas in TR watershed have the highest PAH loadings compared to rural areas. Sensitivity analyses of the PAH soil and PAH water parameters were also able to determine the critical processes in TR watershed: degradation, deposition, volatilization, and wash off mechanism. We hope that this model will be able to aid the stakeholders in: regulating PAH concentrations emitted by various sources; and also apply the model to other Persistent Organic Pollutants (POPs).

  17. Watershed-scale modeling on the fate and transport of polycyclic aromatic hydrocarbons (PAHs)

    Energy Technology Data Exchange (ETDEWEB)

    Ligaray, Mayzonee; Baek, Sang Soo [School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology, UNIST-gil 50, Ulsan 44919 (Korea, Republic of); Kwon, Hye-Ok [Disaster Scientific Investigation Division, National Disaster Management Research Institute, 365 Jongga-ro Jung-gu, Ulsan 44538 (Korea, Republic of); Choi, Sung-Deuk, E-mail: sdchoi@unist.ac.kr [School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology, UNIST-gil 50, Ulsan 44919 (Korea, Republic of); Cho, Kyung Hwa, E-mail: khcho@unist.ac.kr [School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology, UNIST-gil 50, Ulsan 44919 (Korea, Republic of)

    2016-12-15

    PAHs are potentially carcinogenic substances that are persistent in the environment. Increasing concentrations of PAHs were observed due to rapid urbanization, thus; monitoring PAHs concentrations is necessary. However, it is expensive to conduct intensive monitoring activities of a large number of PAHs. This study addressed this issue by developing a multimedia model coupled with a hydrological model (i.e., Soil and Water Assessment Tool (SWAT)) for Taehwa River (TR) watershed in Ulsan, the industrial capital of South Korea. The hydrologic module of the SWAT was calibrated, and further used to simulate the fate and transport of PAHs in soil and waterbody. The model demonstrated that the temporal or seasonal variation of PAHs in soil and waterbody can be well reproduced. Meanwhile, the spatial distribution of PAHs showed that urban areas in TR watershed have the highest PAH loadings compared to rural areas. Sensitivity analyses of the PAH soil and PAH water parameters were also able to determine the critical processes in TR watershed: degradation, deposition, volatilization, and wash off mechanism. We hope that this model will be able to aid the stakeholders in: regulating PAH concentrations emitted by various sources; and also apply the model to other Persistent Organic Pollutants (POPs).

  18. Vegetative cover and PAHs accumulation in soils of urban green space

    International Nuclear Information System (INIS)

    Peng Chi; Ouyang Zhiyun; Wang Meie; Chen Weiping; Jiao Wentao

    2012-01-01

    We investigated how urban land uses influence soil accumulation of polycyclic aromatic hydrocarbons (PAHs) in the urban green spaces composed of different vegetative cover. How did soil properties, urbanization history, and population density affect the outcomes were also considered. Soils examined were obtained at 97 green spaces inside the Beijing metropolis. PAH contents of the soils were influenced most significantly by their proximity to point source of industries such as the coal combustion installations. Beyond the influence circle of industrial emissions, land use classifications had no significant effect on the extent of PAH accumulation in soils. Instead, the nature of vegetative covers affected PAH contents of the soils. Tree–shrub–herb and woodland settings trapped more airborne PAH and soils under these vegetative patterns accumulated more PAHs than those of the grassland. Urbanization history, population density and soil properties had no apparent impact on PAHs accumulations in soils of urban green space. - Highlights: ► Land use did not affect PAHs in soils except for areas adjacent to industrial sources. ► Tree–shrub–herb and woodland cover amass more PAHs in soils than grassland cover. ► Urban development and soil property factors had little effect on PAHs in soils. - Industrial emissions aside, vegetative cover is the dominant factor controlling accumulation of PAHs in urban green space soils.

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

    Directory of Open Access Journals (Sweden)

    M. Margaret Pratt

    2011-06-01

    Full Text Available 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.

  20. Fusion rings and fusion ideals

    DEFF Research Database (Denmark)

    Andersen, Troels Bak

    by the so-called fusion ideals. The fusion rings of Wess-Zumino-Witten models have been widely studied and are well understood in terms of precise combinatorial descriptions and explicit generating sets of the fusion ideals. They also appear in another, more general, setting via tilting modules for quantum......This dissertation investigates fusion rings, which are Grothendieck groups of rigid, monoidal, semisimple, abelian categories. Special interest is in rational fusion rings, i.e., fusion rings which admit a finite basis, for as commutative rings they may be presented as quotients of polynomial rings...