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1

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

PubMed

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

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

2011-11-23

2

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

PubMed

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

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

2013-06-03

3

PAHs in the Fraser River basin: a critical appraisal of PAH ratios as indicators of PAH source and composition  

Microsoft Academic Search

Parent and alkyl PAHs (51 compounds and alkyl homologues) have been quantified in suspended particulates and sediments (345 samples) from the Fraser River system, British Columbia, Canada. The best potential to distinguish natural and anthropogenic sources is exhibited by ratios of the principal mass 178, 202, 228 and 276 parent PAHs, 1,7\\/2,6+1,7-DMP (dimethylphenanthrene), the phenanthrene\\/anthracene and fluoranthene\\/pyrene alkyl PAH series

Mark B Yunker; Robie W Macdonald; Roxanne Vingarzan; Reginald H Mitchell; Darcy Goyette; Stephanie Sylvestre

2002-01-01

4

Polycyclic aromatic hydrocarbons and their molecular diagnostic ratios in urban atmospheric respirable particulate matter  

NASA Astrophysics Data System (ADS)

Atmospheric concentrations of polycyclic aromatic hydrocarbons (PAHs) in Santiago de Chile city were evaluated to study particulate PAHs profiles during cold and spring weather periods. Urban atmospheric particulate matter PM10 was collected using High Volume PM10 samplers. Fifteen samples of 24 h during austral winter and 20 samples of 24 h during spring, 2000 were collected at two sampling sites (North East and Central areas of the city) whose characteristics were representative of the prevailing conditions. Seventeen PAHs were quantified and total PAHs concentration ranged from 1.39 to 59.98 ng m-3, with a seasonal variation (winter vs. spring ratio) from 0.5 to 12.6 ng m-3. Molecular diagnostic ratios were used to characterize and identify PAHs emission sources such as combustion and biogenic emissions. Results showed that the major sources of respirable organic aerosol PM10 in Santiago are mobile and stationary ones.

Del Rosario Sienra, María; Rosazza, Nelson G.; Préndez, Margarita

2005-06-01

5

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

NASA Astrophysics Data System (ADS)

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

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

2009-04-01

6

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

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

7

Concentration and composition of polycyclic aromatic hydrocarbons (PAHs) in plastic pellets: Implications for small-scale diagnostic and environmental monitoring.  

PubMed

Plastic pellets may serve as a carrier of toxic contaminants, including polycyclic aromatic hydrocarbons (PAHs). Considering that beach morphodynamics and pellet distribution varied along the shore, and that contaminant sources may vary on different scales, it is expected that this variability is reflected in the concentration and composition of contaminants. This hypothesis was tested through a sampling of plastic pellets at 30 sites along the shore in Santos Bay (Brazil). The total PAH concentrations and the priority PAHs showed high variability, with no clear pattern. Their composition differed among the sampling sites; some of the compounds represent a potential risk to organisms. The sources of contamination, as indicated by the isomer ratios, were also variable among sites. The high small-scale spatial variability found here has implications for estimating the plastic pellet contamination on beaches, since a sample from a single site is unlikely to be representative of an entire beach. PMID:24125130

Fisner, Mara; Taniguchi, Satie; Majer, Alessandra P; Bícego, Márcia C; Turra, Alexander

2013-10-11

8

Source apportionment of polycyclic aromatic hydrocarbons in surface sediment of mud areas in the East China Sea using diagnostic ratios and factor analysis.  

PubMed

Polycyclic aromatic hydrocarbons (PAHs) and aliphatic hydrocarbons (AHs) have been quantified for surface sediments collected from the East China Sea (ECS). Our results showed that relatively high levels of PAHs and AHs occurred in both the inner and outer mud areas, while their concentrations at the control site were much lower. AHs for all samples were dominated by the unresolved complex mixture (UCM). Results from diagnostic ratios revealed that sedimentary PAHs were mainly originated from mixed combustion residues of biomass, coal, and petroleum. Combustion residues of petroleum and oil were responsible for the presence of high AHs concentrations. We also conducted factor analysis (FA) to further characterize the PAH and AH sources. Four factors were identified based on the loading of components and attributed to coal and wood combustion (Factor 1), traffic-related sources (Factor 2), petrogenic source (Factor 3) and natural gas combustion (Factor 4). PMID:23541289

Deng, Wei; Li, Xian Guo; Li, Sheng Yong; Ma, Yan Yan; Zhang, Da Hai

2013-03-26

9

Environmental stability of PAH source indices in pyrogenic tars  

SciTech Connect

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

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

2006-04-15

10

Using atmospheric measurements of PAH and quinone compounds at roadside and urban background sites to assess sources and reactivity  

NASA Astrophysics Data System (ADS)

The sources of polycyclic aromatic hydrocarbon (PAH) in various environmental media have commonly been identified based on the ratios of concentrations of selected PAH congeners. These ratios are applicable to various environmental media and distinguish between sources originating from vehicular emissions, petroleum products, petroleum combustion, coal and biomass burning. In this study an evaluation of PAH diagnostic ratios is provided for vapour and particulate phase samples collected simultaneously at well defined roadside and suburban sites in Birmingham, UK. It focuses on 14 PAH and 11 quinone compounds which were measured at both sites to obtain information upon traffic emissions (and subsequently a PAH congener traffic profile) and to evaluate the validity of PAH diagnostic ratios. The results suggest that PAH ratios of the low molecular weight compounds are less stable and more susceptible to atmospheric processing, indicating the importance of determining PAH ratio threshold values based on well defined samples. Quinone to parent-PAH ratios were also examined to assess the potential reactivity of PAH compounds, where the results suggest that significant atmospheric processing occurs during transport, altering the ratios between both sites, in a manner related to the relative reactivity of different PAH congeners.

Alam, Mohammed S.; Delgado-Saborit, Juana Maria; Stark, Christopher; Harrison, Roy M.

2013-10-01

11

Polycyclic aromatic hydrocarbons study in atmospheric fine and coarse particles using diagnostic ratios and receptor model in urban/industrial region.  

PubMed

Atmospheric fine and coarse particles were collected in Teflon filters in three cities of the region of the Lower Sinos River Basin of Rio Grande do Sul in the year 2010. The filters were Soxhlet extracted, and 14 priority PAHs were analyzed using a gas chromatograph coupled to a mass spectrometer (GC/MS). The principal emission sources of these compounds were assessed by using diagnostic ratios and receptor model: positive matrix factorization (PMF 3.0) of the US Environmental Protection Agency. The results of PAHs concentration for the studied year showed significant levels of high molecular weight (HMW) PAH, Ind, and BghiP, in PM2.5 in the winter season, showing the influence of mobile sources. The application of receptor model PMF 3.0 revealed that the main sources of PAHs were vehicle fleet (both diesel and gasoline), followed by coal combustion, wood combustion, and resuspension of dust. The results of the receptor modeling are in agreement with the data obtained by the ratio diagnostic. PMID:23824515

Teixeira, Elba Calesso; Mattiuzi, Camila Dalla Porta; Agudelo-Castañeda, Dayana Milena; de Oliveira Garcia, Karine; Wiegand, Flavio

2013-07-04

12

Making a diagnosis in PAH  

Microsoft Academic Search

Poor survival among patients with untreated pulmonary arterial hypertension (PAH) means that timely and accurate diagnosis is of paramount importance. However, the nonspecific nature of PAH symptoms, which include breathlessness and fatigue, make PAH a considerable diagnostic challenge. As a result, many patients are passed among different physicians and are only correctly diagnosed at relatively advanced stages of disease, when

J. S. R. Gibbs

2007-01-01

13

Application of Response Surface Methodology to Analyze the Effects of Soil\\/Liquid Ratio, pH, and Incubation Time on the Bioaccessibility of PAHs from Soil in In Vitro Method  

Microsoft Academic Search

Central composite design using response surface methodology was employed to optimize soil\\/liquid ratio (S\\/L), pH, and incubation\\u000a time for polycyclic aromatic hydrocarbons (PAHs) bioaccessibility from soil in a simulated gastrointestinal tract. The magnitude\\u000a of PAHs bioaccessibility in intestinal tract was found higher than that in gastric tract. Results showed that S\\/L had significant\\u000a negative effects on the bioaccessibility of PAHs

M. Lu; D. Yuan; Q. Li; T. Ouyang

2009-01-01

14

Determination of the local equivalence ratio of methane/air mixtures by spark diagnostics  

NASA Astrophysics Data System (ADS)

Determination of local equivalence ratio by spark diagnostics has been successfully realized. It was found that the rate of current growth during breakdown (or time derivative of current, dI/dt) depends on the methane content in its mixture with air. This effect was used to detect the local equivalence ratio in the zone of the spark electrodes during the injection of methane into air. The relationship between the inductive voltage Ui, detected in measuring circuit and related to dI/dt, and the value of equivalence ratio was initially obtained with quiescent methane/air mixtures of different methane contents. The results obtained with spark diagnostics in dynamic conditions have been validated by a misfiring study. The main advantage of the diagnostics applied is that equivalence ratio monitoring is carried out directly over a spark plug gap and the same electrodes are used both for diagnostics and for ignition.

Bellenoue, M.; Kageyama, T.; Labuda, S. A.

2004-01-01

15

[Size distribution of polycyclic aromatic hydrocarbons (PAHs) in different function zones of Guangzhou in autumn, China].  

PubMed

Size distribution of aerosol samples collected from two urban locations (Liwan and Wushan) and a suburban location (Xinken) in Guangzhou (South China) in autumn using Micro-Orifice Uniform Deposit Impactor (MOUDI) were analyzed for 13 polycyclic aromatic hydrocarbons (PAHs) by gas chromatography with mass selective detection (GC-MS). Bimodal distribution was found for 3- and 4-ring PAHs and unimodal for 5-, 6- and 7-ring PAHs. Different PAH size distribution models were found for urban and suburban. PAHs associated with larger particles in suburban than in urban, and different aging processes of aerosols can account for it. Adsorption behavior may be the main mechanism controlled the size distribution of PAHs in urban, and adsorption, absorption and multilayer adsorption may all play a part in suburban. For the diagnostic ratios of PAHs with the same molecular weight, large differences were found between the range of 1-2.5 microm and 0.1-0.56 microm. The concentrations of 13 PAHs were 39 ng/m3 in Xinken, 71-94 ng/m3 in Wushan and 32-154 ng/m3 in Liwan, and 5-7 ring PAHs were the most abundant. PMID:16767976

Duan, Jing-chun; Bi, Xin-hui; Tan, Ji-hua; Sheng, Guo-ying; Fu, Jia-mo; Hao, Ji-ming

2006-04-01

16

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

PubMed

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 ?m) were the predominant particle size (56-97%). Lacustrine source (with the peak towards 200-400 ?m) and eolian sources derived from short (2.0-10 and 30-65 ?m) and long (0.4-1.0 ?m) 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 ?m 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 ?m 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. PMID:23727602

Sun, Li; Zang, Shuying

2013-05-28

17

The stability and utility of diagnostic ratio hydrocarbon fingerprinting for soils contaminated with petroleum hydrocarbons  

SciTech Connect

In order to recover costs for oil spill cleanup and restoration regulatory agencies and trustees of natural resources are interested in identifying parties responsible for hydrocarbon releases, and for associated environmental damages. Chemical analyses of contaminated soil and groundwater samples are currently used to identify the sources of contamination in soil and groundwater systems. However, conventional hydrocarbon fingerprinting approaches such as EPA Method 8015, EPA Method 8270, and ASTM Method 3328-91 afford a low resolution fingerprint that is easily degraded in the environment. The challenge to the hydrocarbon chemist is to develop an analytical approach that minimizes the impact of environmental weathering and biodegradation on the oil signature and improves the accuracy of oil source identification. An advanced chemical fingerprinting strategy is presented that combines sensitive and hydrocarbon specific analytical methods with a detailed interpretive strategy designed to minimize the impacts of environmental weathering and biodegradation. Data will be presented from a series of oil biodegradation studies in soil that clearly demonstrate the utility and stability of source ratio analysis over a wide range of oil degradation states and oil types. Using principal component analysis, stable source ratios of C[sub 3]-dibenzothiophenes/C[sub 3]-phenanthrenes, and C[sub 2]-dibenzothiophenes/C[sub 2]-phenanthrenes were identified and evaluated. These source ratios retain their characteristic source ratio signature even after 95 percent of the PAH and dibenzothiophene target analytes and 70 percent of the total oil has been biodegraded.

Douglas, G.S.; Sara McMillen

1996-01-01

18

Source seasonality of polycyclic aromatic hydrocarbons (PAHs) in a subtropical city, Guangzhou, South China.  

PubMed

Mega-cities are large sources of air pollution on a regional base. Differences in energy structures, geographical settings and regional climate features lead to a large variety of air pollution sources from place to place. To understand the seasonality of air pollution sources is critical to precise emission inventories and a sound protection of human health. Based on a year-round dataset, the sources of PAHs in the air of Guangzhou were drawn by principal factor analysis (PCA) in combination with diagnostic ratios, and the seasonality of these sources were analyzed by PCA/MLR (multiple linear regressions) and discussed. The average total gaseous and particulate PAHs concentrations were 313 and 23.7 ng m(-3), respectively, with a higher concentration of vapor PAHs in summer and particulate PAHs in winter. In addition to vehicle exhaust, which contributed 69% of the particulate PAHs, coal combustion was still an important source and contributed 31% of the particulate PAHs. Relatively constant contribution from coal combustion was found through the year, implying that coal combustion in power plants was not a seasonally dependent source. Evaporation from contaminated ground may be an important source of light PAHs in summer, providing an average contribution of 68% to the total PAHs in this study. By comparing the PAH concentrations and meteorological parameters, we found that higher concentrations of particulate PAHs in winter resulted from enhanced vehicle exhaust under low temperature and accumulation of pollutants under decreased boundary layer, slower wind speed, and long-term dryness conditions. It is suggested that the typical subtropical monsoon climate in South China, cool and dry in winter, hot and humid in summer, may play a key role in controlling the source seasonality (by enhancing vehicle exhaust in winter, ground evaporation in summer), and hence the ambient concentrations of PAHs in the air. PMID:16137742

Li, J; Zhang, G; Li, X D; Qi, S H; Liu, G Q; Peng, X Z

2005-08-31

19

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

Microsoft Academic Search

Although polycyclic aromatic hydrocarbons (PAHs) are also of natural origin, in many regions their environmental concentrations have strongly increased due to human activities. These semivolatile organic compounds are generally formed during incomplete combustion. Other sources include volatilization from unburned petroleum or tire abrasion in road traffic. Among all pollutants PAHs pose the highest human health hazard in Europe (WHO, 2003).

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

2009-01-01

20

Profile of PAHs in the inhalable particulate fraction: source apportionment and associated health risks in a tropical megacity.  

PubMed

The present study proposed to investigate the atmospheric distribution, sources, and inhalation health risks of polycyclic aromatic hydrocarbons (PAHs) in a tropical megacity (Delhi, India). To this end, 16 US EPA priority PAHs were measured in the inhalable fraction of atmospheric particles (PM(10); aerodynamic diameter, ? 10 ?m) collected weekly at three residential areas in Delhi from December 2008 to November 2009. Mean annual 24 h PM(10) levels at the sites (166.5-192.3 ?g m(-3)) were eight to ten times the WHO limit. Weekday/weekend effects on PM(10) and associated PAHs were investigated. ?(16)PAH concentrations (sum of 16 PAHs analyzed; overall annual mean, 105.3 ng m(-3); overall range, 10.5-511.9 ng m(-3)) observed were at least an order of magnitude greater than values reported from European and US cities. Spatial variations in PAHs were influenced by nearness to traffic and thermal power plants while seasonal variation trends showed highest concentrations in winter. Associations between ?(16)PAHs and various meteorological parameters were investigated. The overall PAH profile was dominated by combustion-derived large-ring species (85-87 %) that were essentially local in origin. Carcinogenic PAHs contributed 58-62 % to ?(16)PAH loads at the sites. Molecular diagnostic ratios were used for preliminary assessment of PAH sources. Principal component analysis coupled with multiple linear regression-identified vehicular emissions as the predominant source (62-83 %), followed by coal combustion (18-19 %), residential fuel use (19 %), and industrial emissions (16 %). Spatio-temporal variations and time-evolution of source contributions were studied. Inhalation cancer risk assessment showed that a maximum of 39,780 excess cancer cases might occur due to lifetime inhalation exposure to the analyzed PAH concentrations. PMID:22527461

Sarkar, Sayantan; Khillare, P S

2012-04-20

21

Near infrared hydrogen emission line ratios as diagnostics of the broad emission line region  

NASA Astrophysics Data System (ADS)

Broad emission line flux ratios are a powerful diagnostic of the physical conditions of the broad-line region gas in Active Galactic Nuclei. With recent advances in infrared spectroscopy, previously unstudied emission lines provide a new means to investigate the physical nature of the BELR gas. The hydrogen emission lines are particularly sensitive to the upper limits of both the radius from the central ionising source and the number density of the gas. Using an existing subset of near-infrared quasar spectra from the Glikman et al. (2006) sample [1] together with Cloudy photoionization simulations, we confirm the Locally Optimally emitting Cloud (LOC) model's ability to reproduce observed emission line flux ratios. The model is then used to constrain physical conditions for individual sources. The photoionization models show that high number density, low incident flux gas is required to reproduce observed near-infrared hydrogen emission line ratios. We also find that comparison to individual sources, rather than composites, is vital.

Ruff, Andrea J.; Floyd, David J. E.; Korista, Kirk T.; Webster, Rachel L.; Porter, Ryan L.; Ferland, Gary J.

2012-07-01

22

GAS EXCITATION IN ULIRGs: MAPS OF DIAGNOSTIC EMISSION-LINE RATIOS IN SPACE AND VELOCITY  

SciTech Connect

Emission-line spectra extracted at multiple locations across 39 ultraluminous infrared galaxies have been compiled into a spectrophotometric atlas. Line profiles of H{alpha}, [N II], [S II], [O I], H{beta}, and [O III] are resolved and fit jointly with common velocity components. Diagnostic ratios of these line fluxes are presented in a series of plots, showing how the Doppler shift, line width, gas excitation, and surface brightness change with velocity at fixed position and also with distance from the nucleus. One general characteristic of these spectra is the presence of shocked gas extending many kiloparsecs from the nucleus. In some systems, the rotation curves of the emitting gas indicate motions that suggest gas disks, which are most frequent at early merger stages. At these early merger stages, the emission line ratios indicate the presence of shocked gas, which may be triggered by the merger event. We also report the general characteristics of the integrated spectra.

Soto, Kurt T.; Martin, Crystal L. [Physics Department, University of California, Santa Barbara, CA 93106-9530 (United States)

2012-11-15

23

Combined application of ? 13C and molecular ratios in sediment cores for PAH source apportionment in the New York\\/New Jersey harbor complex  

Microsoft Academic Search

Sub-basins within the New York\\/New Jersey (NY\\/NJ) Harbor host variable amounts and sources of polycyclic aromatic hydrocarbons (PAHs). Analyses of radionuclides 137Cs and 7Be were used to assign approximate dates to individual sections of sediment cores collected from four major sub-basins of the harbor complex. Sampling sites range from heavily contaminated Newark Bay and Passaic River to less contaminated Raritan

Beizhan Yan; Teofilo A. Abrajano; Richard F. Bopp; Lucille A. Benedict; Damon A. Chaky; Eric Perry; Jing Song; Dennis P. Keane

2006-01-01

24

Diagnostic accuracy of urinary spot protein:creatinine ratio for proteinuria in hypertensive pregnant women: systematic review  

Microsoft Academic Search

Objective To review the spot protein:creatinine ratio and albumin:creatinine ratio as diagnostic tests for significant proteinuria in hypertensive pregnant women.Design Systematic review.Data sources Medline and Embase, the Cochrane Library, reference lists, and experts.Review methods Literature search (1980-2007) for articles of the spot protein:creatinine ratio or albumin:creatinine ratio in hypertensive pregnancy, with 24 hour proteinuria as the comparator.Results 13 studies concerned

Anne-Marie Côté; Mark A Brown; Elaine Lam; Peter von Dadelszen; Tabassum Firoz; Robert M Liston; Laura A Magee

2008-01-01

25

Ratios  

NSDL National Science Digital Library

This "homework help" lesson introduces students to ratios, ratio language, equivalent ratios, and allows students to practice with a set of problems at the end. The lesson is divided into four parts: First Glance, In Depth, Examples, and Workout.

2005-01-01

26

Gas Excitation in ULIRGs: Maps of Diagnostic Emission-line Ratios in Space and Velocity  

NASA Astrophysics Data System (ADS)

Emission-line spectra extracted at multiple locations across 39 ultraluminous infrared galaxies have been compiled into a spectrophotometric atlas. Line profiles of H?, [N II], [S II], [O I], H?, and [O III] are resolved and fit jointly with common velocity components. Diagnostic ratios of these line fluxes are presented in a series of plots, showing how the Doppler shift, line width, gas excitation, and surface brightness change with velocity at fixed position and also with distance from the nucleus. One general characteristic of these spectra is the presence of shocked gas extending many kiloparsecs from the nucleus. In some systems, the rotation curves of the emitting gas indicate motions that suggest gas disks, which are most frequent at early merger stages. At these early merger stages, the emission line ratios indicate the presence of shocked gas, which may be triggered by the merger event. We also report the general characteristics of the integrated spectra. The data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

Soto, Kurt T.; Martin, Crystal L.

2012-11-01

27

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

NASA Astrophysics Data System (ADS)

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

Srivastava, A. K.; et al.

2006-11-01

28

Seasonal variation of PM10-bound PAHs in the atmosphere of Xiamen, China  

NASA Astrophysics Data System (ADS)

PM10 samples from a garden site (site A), an industrial-traffic intersection (site B), a residential site (site C) and an island site (site D) were collected at December 21 29, 2004; March 18 22, 2005; July 4 13, 2005 and October 24 28, 2005 in Xiamen. 15 priority PAHs compounds were analyzed by using a gas chromatograph/mass spectrometer (GC/MS). The abundance and origin of PAHs are discussed to reveal seasonal variations in Xiamen air quality. Average concentrations of ?15PAHs were 17.5 ng/m3, 3.7 ng/m3, 32.6 ng/m3 and 10.5 ng/m3 from spring to winter with the highest value in autumn. The dominant PAHs components in every season were low and middle molecular weight PAHs including phenanthrene, pyrene, fluoranthene and chrysene. Diagnostic ratios and PCA analysis identified the main sources of particle bound PAHs: mainly from both gasoline and diesel vehicles exhaust, with some contribution from coal combustion, industry emission and cooking sources.

Hong, Huasheng; Yin, Hongling; Wang, Xinhong; Ye, Cuixing

2007-09-01

29

Ratios  

NSDL National Science Digital Library

This set of instructional materials and problems helps students understand ratios and proportions, starting with a simple review and progressing into the more advanced territory of similar triangles. The first three pages introduce ratios, proportions, and checking proportionality and the last four pages present mathematical and real-world problems for students to solve given their understanding of ratios and proportions.

Stapel, Elizabeth

2000-01-01

30

Ambient concentrations and personal exposure to polycyclic aromatic hydrocarbons (PAH) in an urban community with mixed sources of air pollution.  

PubMed

Assessment of the health risks resulting from exposure to ambient polycyclic aromatic hydrocarbons (PAH) is limited by a lack of environmental exposure data among the general population. This study characterized personal exposure and ambient concentrations of PAH in the Village of Waterfront South (WFS), an urban community with many mixed sources of air toxics in Camden, New Jersey, and CopeWood/Davis Streets (CDS), an urban reference area located ?1 mile east of WFS. A total of 54 and 53 participants were recruited from non-smoking households in WFS and CDS, respectively. In all, 24-h personal and ambient air samples were collected simultaneously in both areas on weekdays and weekends during summer and winter. The ambient PAH concentrations in WFS were either significantly higher than or comparable to those in CDS, indicating the significant impact of local sources on PAH pollution in WFS. Analysis of diagnostic ratios and correlation suggested that diesel truck traffic, municipal waste combustion and industrial combustion were the major sources in WFS. In such an area, ambient air pollution contributed significantly to personal PAH exposure, explaining 44-96% of variability in personal concentrations. This study provides valuable data for examining the impact of local ambient PAH pollution on personal exposure and therefore potential health risks associated with environmental PAH pollution. PMID:21364704

Zhu, Xianlei; Fan, Zhihua Tina; Wu, Xiangmei; Jung, Kyung Hwa; Ohman-Strickland, Pamela; Bonanno, Linda J; Lioy, Paul J

2011-03-02

31

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

PubMed

This study aimed to characterize air pollution and the associated carcinogenic risks of polycyclic aromatic hydrocarbon (PAHs) at an urban site, to identify possible emission sources of PAHs using several statistical methodologies, and to analyze the influence of other air pollutants and meteorological variables on PAH concentrations.The air quality and meteorological data were collected in Oporto, the second largest city of Portugal. Eighteen PAHs (the 16 PAHs considered by United States Environment Protection Agency (USEPA) as priority pollutants, dibenzo[a,l]pyrene, and benzo[j]fluoranthene) were collected daily for 24 h in air (gas phase and in particles) during 40 consecutive days in November and December 2008 by constant low-flow samplers and using polytetrafluoroethylene (PTFE) membrane filters for particulate (PM10 and PM2.5 bound) PAHs and pre-cleaned polyurethane foam plugs for gaseous compounds. The other monitored air pollutants were SO2, PM10, NO2, CO, and O3; the meteorological variables were temperature, relative humidity, wind speed, total precipitation, and solar radiation. Benzo[a]pyrene reached a mean concentration of 2.02 ng?m(-3), surpassing the EU annual limit value. The target carcinogenic risks were equal than the health-based guideline level set by USEPA (10(-6)) at the studied site, with the cancer risks of eight PAHs reaching senior levels of 9.98 × 10(-7) in PM10 and 1.06 × 10(-6) in air. The applied statistical methods, correlation matrix, cluster analysis, and principal component analysis, were in agreement in the grouping of the PAHs. The groups were formed according to their chemical structure (number of rings), phase distribution, and emission sources. PAH diagnostic ratios were also calculated to evaluate the main emission sources. Diesel vehicular emissions were the major source of PAHs at the studied site. Besides that source, emissions from residential heating and oil refinery were identified to contribute to PAH levels at the respective area. Additionally, principal component regression indicated that SO2, NO2, PM10, CO, and solar radiation had positive correlation with PAHs concentrations, while O3, temperature, relative humidity, and wind speed were negatively correlated. PMID:23184127

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

2012-11-27

32

Hyperfine Induced Transitions as Diagnostics of Low Density Plasmas and Isotopic Abundance ratios.  

NASA Astrophysics Data System (ADS)

We propose a new diagnostics of isotope abundance ratios and electron densities for low density plasmas, in the form of J = 0 -> J(') = 0 radiative transitions. These are usually viewed as being allowed only through two-photon decay, but they may also be induced by the hyperfine (HPF) interaction in atomic ions. This predicts a companion line to the E1] and M2 lines in the UV0.01 multiplet of ions isoelectronic to beryllium (e.g. C III, N IV, O V and Fe XXII) or magnesium (e.g. Si II, Ca IX, Fe XV and Ni XVII). As an example the companion line to the well known lambda lambda 1906.7,1908.7 lines in C III will be at 1909.597 Angstroms, but only present in the (13) C isotope (which has nuclear spin different from zero). We present new and accurate decay rates for the nsnp (3P^oJ) -> ns(2) (1S_{J('}=0)) transitions in ions of the Be (n=2) and Mg (n=3) isoelectronic sequences. We show that the HPF induced decay rates for the J = 0 -> J(') = 0 transitions are many orders of magnitude larger than those for the competing two-photon processes and, when present, are typically one or two orders of magnitude smaller than the decay rates of the magnetic quadrupole ( J = 2-> J(') = 0) transitions for these ions. We show that several of these HPF-induced transitions are of potential astrophysical interest, in ions of C, N, Na, Mg, Al, Si, K, Cr, Fe and Ni. We highlight those cases that may be of particular diagnostic value for determining isotopic abundance ratios and/or electron densities from UV or EUV emission line data. We present our atomic data in the form of scaling laws so that, given the isotopic nuclear spin and magnetic moment, a simple expression yields estimates for HPF induced decay rates. We examine some UV solar and nebular data in the light of these new results and suggest possible cases for future study. We could not find evidence for the existence of HPF induced lines in the spectra we examined, but we demonstrate that existing data have come close to providing interesting upper limits. For the planetary nebula SMC N2 we derive an upper limit of (13) C/(12) C of 0.1 from GHRS data obtained by Clegg. It is likely that more stringent limits could be obtained with newer data with higher sensitivities in a variety of objects.

Brage, T.; Judge, P. G.; Aboussaid, A.; Godefroid, M. R.; Jonsson, P.; Leckrone, D. S.

1996-05-01

33

Proportional odds ratio model for comparison of diagnostic tests in meta-analysis  

PubMed Central

Background Consider a meta-analysis where a 'head-to-head' comparison of diagnostic tests for a disease of interest is intended. Assume there are two or more tests available for the disease, where each test has been studied in one or more papers. Some of the papers may have studied more than one test, hence the results are not independent. Also the collection of tests studied may change from one paper to the other, hence incomplete matched groups. Methods We propose a model, the proportional odds ratio (POR) model, which makes no assumptions about the shape of ORp, a baseline function capturing the way OR changes across papers. The POR model does not assume homogeneity of ORs, but merely specifies a relationship between the ORs of the two tests. One may expand the domain of the POR model to cover dependent studies, multiple outcomes, multiple thresholds, multi-category or continuous tests, and individual-level data. Results In the paper we demonstrate how to formulate the model for a few real examples, and how to use widely available or popular statistical software (like SAS, R or S-Plus, and Stata) to fit the models, and estimate the discrimination accuracy of tests. Furthermore, we provide code for converting ORs into other measures of test performance like predictive values, post-test probabilities, and likelihood ratios, under mild conditions. Also we provide code to convert numerical results into graphical ones, like forest plots, heterogeneous ROC curves, and post test probability difference graphs. Conclusions The flexibility of POR model, coupled with ease with which it can be estimated in familiar software, suits the daily practice of meta-analysis and improves clinical decision-making.

Siadaty, Mir Said; Shu, Jianfen

2004-01-01

34

Fitting the observed PAH bands  

NASA Astrophysics Data System (ADS)

The interstellar infrared emission spectrum with strong bands near 3.3, 6.2, 7.7, and 11.2 micron is common throughout the Universe. These bands -- often called the Unidentified InfraRed (UIR) bands or Aromatic InfraRed Bands (AIB) -- dominate the mid-IR spectra of most galactic objects and they have been detected in a large number of extragalactic objects. Not only are these features observed in many different objects, there is also significant variability in the spectroscopic details from one object to another and from one region to another within extended sources. Clearly, these spectra contain a wealth of information which reflects the physical conditions in the emission zones and composition of the emitting materials. Many studies have therefore attempted to use these easily observed features as diagnostic tools for various purposes. It is now widely accepted that this spectrum is produced by fluorescent emission from highly vibrationally excited polycyclic aromatic hydrocarbon molecules (PAHs) and closely related species and the features are now often referred to as the PAH emission bands. In this presentation, we use the NASA Ames PAH IR Spectroscopic Database and a simplified model for PAH physics to present a detailed comparison with observations of the UIR bands representing the different characteristic classes of UIR spectra. We find that we can closely reproduce the observed UIR spectra for all classes in the ranges 6--9 micron and 10--14 micron, offering credibility for the hypothesis that the UIR bands are indeed due to the various vibrational modes of PAHs and related species. We will also show how the spectral variations of the PAH bands in different environments can be explained by differences in the size distribution, the charge state and the precise chemical composition of the contributing molecules.

Cami, Jan; Bauschlicher, C.; Peeters, E.; Mattioda, A.; Allamandola, L.

2009-01-01

35

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

SciTech Connect

The mid-infrared (IR) spectra of six large, irregular polycyclic aromatic hydrocarbons (PAHs) with formulae (C{sub 84}H{sub 24}-C{sub 120}H{sub 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{sub str} band at 6.2 {mu}m, 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 {mu}m for PAH cations. Here we show that this band shifts to 6.3 {mu}m 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 {mu}m appears to directly reflect the PAH cation to anion ratio. Large irregular PAHs exhibit features at 7.8 {mu}m but lack them near 8.6 {mu}m. Hence, the 7.7 {mu}m astronomical feature is produced by a mixture of small and large PAHs while the 8.6 {mu}m band can only be produced by large compact PAHs. As with the CC{sub str}, the position and profile of these bands reflect the PAH cation to anion ratio.

Bauschlicher, Charles W. [NASA-Ames Research Center, Space Technology Division, Mail Stop 230-3, Moffet Field, CA 94035 (United States); Peeters, Els [Department of Physics and Astronomy, University of Western Ontario, London, ON N6A 3K7 (Canada); Allamandola, Louis J. [NASA-Ames Research Center, Space Science Division, Mail Stop 245-6, Moffet Field, CA 94035 (United States)], E-mail: Charles.W.Bauschlicher@nasa.gov, E-mail: epeeters@uwo.ca, E-mail: Louis.J.Allamandola@nasa.gov

2009-05-20

36

[Diagnostic usefulness of the beta-hydroxybutyrate/acetone ratio in medico-legal diagnostics of sudden deaths].  

PubMed

Our previous studies demonstrated the usefulness of screening determinations of acetone as an initial diagnostic criterion in deaths due to hypothermia, alcoholic ketoacidosis, diabetes mellitus, starvation and some poisonings. In alcoholemia, particularly in cases of prolonged ethanol consumption, the above-mentioned conditions may not result in acetonemia, despite marked concentrations of beta-hydroxybutyrate acid (beta-HBA). Therefore, for the purpose of the present study, the method of beta-HBA determination was modified using GC-MS-EI and applied to analyze 47 autopsy blood samples of individuals who died suddenly due to unknown causes. In 15 cases, the concentration of beta-HBA was higher than 1000 micromol/l; in six subjects from this group, the acetone concentration was lower than 250 micromol/l. In some cases, thus, the use of beta-HBA as an additional diagnostic criterion allows for explaining the pathomechanism of premortal metabolic disturbances. PMID:17907621

Buszewicz, Grzegorz; Teresi?ski, Grzegorz; Ba?ka, Krzysztof; Madro, Roman

37

Characterizing PAH emission concentrations in ambient air during a large-scale joss paper open-burning event.  

PubMed

Large-scale open burning of joss paper is an important ritual practice for deity worshipping during Buddhist and Taoist festivals. Since Buddhism and Taoism are two of the most popular religions in Chinese societies and some Asian countries, the impact of joss paper burning on the air quality needs further investigation. This study explores the concentrations of polycyclic aromatic hydrocarbons (PAHs) in ambient air during one of the most important festivals, in which large-scale burning of joss paper occurs in temples and in people's houses. The PAH concentrations were measured simultaneously at a temple site and a background site during both the festival and non-festive (ordinary) periods. Each ambient sample was extracted by the Soxhlet analytical method (for both particle-bound and gas-phase) and analyzed with gas chromatography. Experimental results indicate that the total PAH concentration during the festival period is approximately 4.2 times higher than that during the ordinary period (5384 ng m(-3) vs. 1275 ng m(-3)). This study also employed statistical methods including diagnostic ratios and principal component analysis (PCA) to identify the possible PAH emission sources. Joss paper burning and vehicular emissions are identified as the principal sources of airborne PAHs during the large-scale open-burning event. The results of this work provide useful information for public awareness concerning PAH emission from the open burning of joss paper. PMID:18207636

Lin, Min-Der; Rau, Jui-Yeh; Tseng, Hui-Hsin; Wey, Ming-Yen; Chu, Chien-Wei; Lin, Yu-Hao; Wei, Ming-Chi; Lee, Ching-Hwa

2007-12-15

38

SPITZER IRS SPECTRAL MAPPING OF THE TOOMRE SEQUENCE: SPATIAL VARIATIONS OF PAH, GAS, AND DUST PROPERTIES IN NEARBY MAJOR MERGERS  

SciTech Connect

We have mapped the key mid-IR diagnostics in eight major merger systems of the Toomre sequence (NGC 4676, NGC 7592, NGC 6621, NGC 2623, NGC 6240, NGC 520, NGC 3921, and NGC 7252) using the Spitzer Infrared Spectrograph. With these maps, we explore the variation of the ionized-gas, polycyclic aromatic hydrocarbon (PAH), and warm gas (H{sub 2}) properties across the sequence and within the galaxies. While the global PAH interband strength and ionized gas flux ratios ([Ne III]/[Ne II]) are similar to those of normal star-forming galaxies, the distribution of the spatially resolved PAH and fine structure line flux ratios is significantly different from one system to the other. Rather than a constant H{sub 2}/PAH flux ratio, we find that the relation between the H{sub 2} and PAH fluxes is characterized by a power law with a roughly constant exponent (0.61 {+-} 0.05) over all merger components and spatial scales. While following the same power law on local scales, three galaxies have a factor of 10 larger integrated (i.e., global) H{sub 2}/PAH flux ratio than the rest of the sample, even larger than what it is in most nearby active galactic nuclei. These findings suggest a common dominant excitation mechanism for H{sub 2} emission over a large range of global H{sub 2}/PAH flux ratios in major mergers. Early-merger systems show a different distribution between the cold (CO J = 1-0) and warm (H{sub 2}) molecular gas components, which is likely due to the merger interaction. Strong evidence for buried star formation in the overlap region of the merging galaxies is found in two merger systems (NGC 6621 and NGC 7592) as seen in the PAH, [Ne II], [Ne III], and warm gas line emission, but with no apparent corresponding CO (J = 1-0) emission. The minimum of the 11.3/7.7 {mu}m PAH interband strength ratio is typically located in the nuclei of galaxies, while the [Ne III/[Ne II] ratio increases with distance from the nucleus. Our findings also demonstrate that the variations of the physical conditions within a merger are much larger than any systematic trends along the Toomre sequence.

Haan, S.; Armus, L.; Laine, S.; Surace, J. A.; Diaz-Santos, T.; Beirao, P.; Stierwalt, S. [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); Charmandaris, V. [Department of Physics and Institute of Theoretical and Computational Physics, University of Crete, GR-71003 Heraklion (Greece); Smith, J. D. [Ritter Astrophysical Observatory, University of Toledo, Toledo, OH 43606 (United States); Schweizer, F.; Murphy, E. J. [Observatories of the Carnegie Institution, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Brandl, B. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Evans, A. S.; Hibbard, J. E. [National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States); Yun, M. [Astronomy Department, University of Massachusetts, 710 North Pleasant Street, Amherst, MA 01003 (United States); Jarrett, T. H. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States)

2011-12-01

39

Spitzer IRS Spectral Mapping of the Toomre Sequence: Spatial Variations of PAH, Gas, and Dust Properties in nearby Major Mergers  

NASA Astrophysics Data System (ADS)

We have mapped the key mid-IR diagnostics in eight major merger systems of the Toomre sequence (NGC 4676, NGC 7592, NGC 6621, NGC 2623, NGC 6240, NGC 520, NGC 3921, and NGC 7252) using the Spitzer Infrared Spectrograph. With these maps, we explore the variation of the ionized-gas, polycyclic aromatic hydrocarbon (PAH), and warm gas (H2) properties across the sequence and within the galaxies. While the global PAH interband strength and ionized gas flux ratios ([Ne III]/[Ne II]) are similar to those of normal star-forming galaxies, the distribution of the spatially resolved PAH and fine structure line flux ratios is significantly different from one system to the other. Rather than a constant H2/PAH flux ratio, we find that the relation between the H2 and PAH fluxes is characterized by a power law with a roughly constant exponent (0.61 ± 0.05) over all merger components and spatial scales. While following the same power law on local scales, three galaxies have a factor of 10 larger integrated (i.e., global) H2/PAH flux ratio than the rest of the sample, even larger than what it is in most nearby active galactic nuclei. These findings suggest a common dominant excitation mechanism for H2 emission over a large range of global H2/PAH flux ratios in major mergers. Early-merger systems show a different distribution between the cold (CO J = 1-0) and warm (H2) molecular gas components, which is likely due to the merger interaction. Strong evidence for buried star formation in the overlap region of the merging galaxies is found in two merger systems (NGC 6621 and NGC 7592) as seen in the PAH, [Ne II], [Ne III], and warm gas line emission, but with no apparent corresponding CO (J = 1-0) emission. The minimum of the 11.3/7.7 ?m PAH interband strength ratio is typically located in the nuclei of galaxies, while the [Ne III/[Ne II] ratio increases with distance from the nucleus. Our findings also demonstrate that the variations of the physical conditions within a merger are much larger than any systematic trends along the Toomre sequence.

Haan, S.; Armus, L.; Laine, S.; Charmandaris, V.; Smith, J. D.; Schweizer, F.; Brandl, B.; Evans, A. S.; Surace, J. A.; Diaz-Santos, T.; Beirão, P.; Murphy, E. J.; Stierwalt, S.; Hibbard, J. E.; Yun, M.; Jarrett, T. H.

2011-12-01

40

XUV diagnostic line ratios for carbon-like Ca XV and a comparison with tokamak plasma observations  

Microsoft Academic Search

New R-matrix calculations of electron impact excitation rates in Ca XV are used to rederive theoretical electron density diagnostic emission line ratios involving 2s22p2-2s2p3 transitions in the wavelength range ? 140-160 Å. A comparison of these with observational data from the TEXT tokamak plasma reveals better agreement between theory and observation than was found previously. This provides experimental support for

F P Keenan; K M Aggarwal; K A Berrington

1992-01-01

41

XUV diagnostic line ratios for carbon-like Ca XV and a comparison with tokamak plasma observations  

Microsoft Academic Search

New R-matrix calculations of electron impact excitation rates in Ca XV are used to rederive theoretical electron density diagnostic emission line ratios involving 2s22p2-2s2p3 transitions in the wavelength range ~ 140-160 Å. A comparison of these with observational data from the TEXT tokamak plasma reveals better agreement between theory and observation than was found previously. This provides experimental support for

F. P. Keenan; K. M. Aggarwal; K. A. Berrington

1992-01-01

42

Evaluation of Cerebrospinal Fluid Tau\\/Beta-Amyloid(42) Ratio as Diagnostic Markers for Alzheimer Disease  

Microsoft Academic Search

Background: Alzheimer’s disease (AD) is the leading cause of dementia. Currently, no definitive diagnostic test for AD exists. Cerebrospinal fluid (CSF) concentrations of amyloid ? (A?1-42) peptides and total tau proteins (T-tau) may serve as biomarkers for AD. Aim: The objective of this study was to investigate the usefulness of CSF A?1-42 and T-tau analyses in the diagnosis of AD

Mohamed Ali Smach; Bassem Charfeddine; Leila Ben Othman; Turkia Lammouchi; Hedi Dridi; Souhir Nafati; Afef Ltaief; Soufien Bennamou; Khalifa Limem

2009-01-01

43

Fate of airborne PAH and nitro-PAH  

SciTech Connect

The authors discuss how the search for major mutagens associated with airborne particulate matter has evolved from investigations of polycyclic aromatic hydrocarbons (PAH) through studies of nitro-PAH, PAH-quinones and other oxygenated derivatives to analysis of various mixed functionality compounds such as nitrohydroxy-PAH. It has been shown that the PAH class itself only accounts for a minor part of the mutagenicity in ambient airborne particulate matter. Therefore, interest in nitro-PAH, PAH-quinones and the oxygenated derivatives of PAHs has grown in recent years.

Greenberg, A.; Darack, F.; Wang, Y. (New Jersey Inst. of Tech., Newark, NJ (USA)); Harkov, R.; Louis, J. (New Jersey Dept. of Environmental Protection, Trenton, NJ (USA)); Atherholt, T. (Coriell Institute for Medical Research, Camden, NJ (US))

1987-01-01

44

Single-colour diagnostics of the mass-to-light ratio - I. Predictions from galaxy formation models  

NASA Astrophysics Data System (ADS)

Accurate galaxy stellar masses are crucial to better understand the physical mechanisms driving the galaxy formation process. We use synthetic star formation and metal enrichment histories predicted by the GALFORM galaxy formation model to investigate the precision with which various colours (ma - mb) can alone be used as diagnostics of the stellar mass-to-light ratio. As an example, we find that, at z = 0, the intrinsic (Bf435w - Vf606w) colour can be used to determine the intrinsic rest-frame V-band stellar mass-to-light ratio (log 10?V = log 10[(M/M?)/(LV/LV?)]) with a precision of ?lg? ? 0.06 when the initial mass function and redshift are known beforehand. While the presence of dust, assuming a universal attenuation curve, can have a systematic effect on the inferred mass-to-light ratio using a single-colour relation, this is typically small as it is often possible to choose a colour for which the dust reddening vector is approximately aligned with the (ma - mb)-log 10?V relation. The precision with which the stellar mass-to-light ratio can be recovered using a single-colour diagnostic rivals implementations of spectral energy distribution (SED) fitting using more information but in which simple parametrizations of the star formation and metal enrichment histories are assumed. To facilitate the wide use of these relations, we provide the optimal observer frame colour to estimate the stellar mass-to-light ratio, along with the associated parameters, as a function of redshift (0 < z < 1.5) for two sets of commonly used filters.

Wilkins, Stephen M.; Gonzalez-Perez, Violeta; Baugh, Carlton M.; Lacey, Cedric G.; Zuntz, Joe

2013-05-01

45

Diagnostic value of the copper\\/zinc ratio in hepatocellular carcinoma: a case control study  

Microsoft Academic Search

Background:   The aim of this study was to assess the accuracy of the copper\\/zinc ratio in the evaluation of a group of patients with hepatocellular\\u000a carcinoma (HCC). Methods: A total of 105 patients were studied and separated into three groups: group I (n = 40), patients with HCC, group II (n = 25), patients with liver cirrhosis, and group III

Jorge L. Poo; Reina Rosas-Romero; Ana C. Montemayor; Fernando Isoard; Misael Uribe

2003-01-01

46

Diagnostic accuracy of urinary protein-to-creatinine ratio in a tertiary referral centre  

Microsoft Academic Search

BackgroundThe gold standard for diagnosing proteinuria in pregnancy is ?300 mg of protein in a 24-h urine collection.1 Practical considerations have reduced the utility of this investigation and National Institute for Health and Clinical Excellence have recommended that a diagnosis of significant proteinuria can be made using a spot urinary protein-to-creatinine ratio (PCR).2 Given the reported variation in protein assay

S J Wang; J Myers

2011-01-01

47

Virtual air-fuel ratio sensors for engine control and diagnostics  

Microsoft Academic Search

Virtual air-fuel ratio sensors for an internal combustion engine using recurrent neural and wavelet networks have been developed. A nonlinear state-space modeling strategy is proposed for the architecture of the stated recurrent neural network which is trained using some variants of real time recurrent learning (RTRL) algorithm. A two-stage training approach is proposed for improving the accuracy of the RNN

Shivaram S. Kamat; Hossein Javaherian; Vivek V. Diwanji; Jessy G. Smith; K. P. Madhavan

2006-01-01

48

Fitting the observed PAH bands  

NASA Astrophysics Data System (ADS)

The space-borne infrared telescopes ISO and Spitzer have shown that the interstellar infrared emission spectrum with strong bands near 3.3, 6.2, 7.7, and 11.2 micron is common throughout the Universe. These bands - often called the Unidentified InfraRed (UIR) bands or Aromatic InfraRed Bands (AIB) - dominate the mid-IR spectra of most galactic objects and they have been detected in a large number of extragalactic objects. Not only are these features observed in many different objects, there is also significant variability in the spectroscopic details from one object to another and from one region to another within extended sources. Clearly, these spectra contain a wealth of information which reflects the physical conditions in the emission zones and composition of the emitting materials. Many studies have therefore attempted to use these easily observed features as diagnostic tools for various purposes. However, a full exploitation of these astronomical spectra has been held back by lack of fundamental data on suitable emitting materials of sufficient breadth and depth to probe the astrophysical environments in which they are observed. It is now widely accepted that this spectrum is produced by fluorescent emission from highly vibrationally excited polycyclic aromatic hydrocarbon molecules (PAHs) and closely related species and the features are now often referred to as the PAH emission bands. In this presentation, we use the NASA Ames database of theoretically calculated frequencies and intensities for a large number of Polycyclic Aromatic Hydrocarbon (PAH) molecules and closely related species and present a detailed comparison with observations of the so-called Unidentified InfraRed (UIR) bands representing the different characteristic classes of UIR spectra. We find that we can closely reproduce the observed UIR spectra for all classes in the ranges 6-9 micron and 10-14 micron, offering credibility for the hypothesis that the UIR bands are indeed due to the various vibrational modes of PAHs and related species. We will also show how the spectral variations of the PAH bands in different environments can be explained by differences in the size distribution, the charge state and the precise chemical composition of the contributing molecules.

Cami, Jan; Allamandola, Louis; Bauschlicher, Charles; Peeters, Els; Mattioda, Andy; Hudgins, Doug

49

Principles of microbial PAH-degradation in soil  

Microsoft Academic Search

Interest in the biodegradation mechanisms and environmental fate of polycyclic aromatic hydrocarbons (PAHs) is motivated by their ubiquitous distribution, their low bioavailability and high persistence in soil, and their potentially deleterious effect on human health. Due to high hydrophobicity and solid–water distribution ratios, PAHs tend to interact with non-aqueous phases and soil organic matter and, as a consequence, become potentially

Anders R. Johnsen; Lukas Y. Wick; Hauke Harms

2005-01-01

50

Monte Carlo study of grid performance in diagnostic radiology: factors which affect the selection of tube potential and grid ratio.  

PubMed

A Monte Carlo computational model has been developed for the study of the performance of anti-scatter grids in diagnostic radiology. It is used here to estimate the scatter in the image plane from soft tissue phantoms (representing the patient) and to calculate image contrast and the mean absorbed dose in the phantom. Different scattering conditions, representative of various examinations, have been investigated: adult lumbar spine; small field radiography and fluoroscopy; adult chest and paediatric pelvis and chest. For each scattering condition, the combinations of tube potential and grid ratio have been found which, for a well designed grid, result in the lowest mean absorbed dose in the phantom for a fixed contrast level. In examinations which generate large amounts of scatter, the use of high grid ratios in combination with high tube potentials is favourable with regard to both mean absorbed dose in the phantom and tube charge. When less scatter is generated, either the grid ratio or the tube potential can be varied to achieve the desired contrast level. High grid ratios require shorter exposure times, but need careful alignment in the beam to prevent primary radiation cut-off. It is shown that the air gap technique can be used to reduce patient dose in examinations with small amounts of scatter, but in combinations with a lower tube potential than when a grid is used. PMID:8293262

Sandborg, M; Dance, D R; Carlsson, G A; Persliden, J

1993-12-01

51

Gamma-Ray Line Flux Ratios as Diagnostics of SN Ia Models  

NASA Astrophysics Data System (ADS)

The ^56Ni decay chain that powers the optical output of Type Ia supernovae produces gamma-ray lines at 158, 812 ( ^56Ni decay ) and 847, 1238 keV ( ^56Co decay ). The detection of the line fluxes have been used to show indeed that ^56Ni is produced by explosive nucleosynthesis. We investigate the measurement precision required to use the flux ratios of these lines to each other and to the compton X-ray continuum to distinguish among a variety of SN Ia models. We compare this to using gamma-ray line profiles to distinguish among models.

Lara, Juan; The, Lih-Sin; Leising, Mark

2004-05-01

52

Pahs and Astrobiology  

NASA Astrophysics Data System (ADS)

In dense molecular clouds, the birthplace of stars and planets, interstellar atoms and molecules freeze onto extremely cold dust and ice particles. These ices are processed by ultraviolet light and cosmic rays forming hundreds of far more complex species, some of astrobiological interest. Eventually, these rain down on primordial planets where they take part in the young chemistry on these new worlds. Although the IR spectroscopy and energetic processing of interstellar ice analogs have been studied for nearly 30 years, similar studies of PAH containing ices have only just begun. This paper presents recent results from laboratory studies on the vacuum ultraviolet (VUV) photochemistry of PAHs in water ice at low temperatures to assess the roles they play in the photochemical evolution of interstellar ices and their relevance to astrobiology. A number of "surprises" were found in these studies on PAH containing water-rich ices, indicating that PAHs likely play very important, unexpected roles in cosmic ice chemistry, physics and astrobiology.

Allamandola, L. J.

2011-03-01

53

A diagnostic marker for childhood apraxia of speech: the coefficient of variation ratio.  

PubMed

Terms such as isochrony, syllable segregation, scanning speech and staccato-like rhythmic quality have been used to characterize the temporal regularity that may be a core feature of apraxia of speech. The present report describes a procedure to quantify temporal regularity in children with suspected apraxia of speech (sAOS). Conversational speech samples from 15 such children, together with samples from 30 3-6-year-old children with normal speech acquisition and 30 3-6-year-old children with moderate to severe speech delay of unknown origin, were selected from an audio archive. Signal processing routines were developed to identify and measure the duration of speech and pause events in 24 utterances from the speech samples of each of the 75 speakers. A value termed the coefficient of variation expressed the normalized variability in the durations of each participant's speech events and pause events within each utterance. A metric termed the coefficient of variation ratio, derived by dividing the coefficient of variation for pause events by the coefficient of variation for speech events, expressed a speaker's relative temporal variation in the two domains. The 15 children with sAOS had higher coefficient of variation ratios than the 30 children in each of the two comparison groups, indicating that the children with sAOS had proportionally more variation in the duration of pause events and/or less variation in the duration of speech events. Findings are interpreted as supporting the view that a constraint in speech timing is a core feature of the praxis disorder that defines a developmental form of apraxia of speech. PMID:14608800

Shriberg, Lawrence D; Green, Jordan R; Campbell, Thomas F; McSweeny, Jane L; Scheer, Alison R

54

Source apportionment of urban particulate aliphatic and polynuclear aromatic hydrocarbons (PAHs) using multivariate methods.  

PubMed

Samples of organic aerosol were collected in Santiago de Chile. An activated-charcoal diffusion denuder was used to strip out organic vapors prior to particle collection. Both polynuclear aromatic hydrocarbons (PAHs) and aliphatic hydrocarbons were determined using gas chromatography/mass spectrometry (GC/MS). Organic particle sources were resolved using both concentration diagnostic ratios and multivariate methods such as hierarchical cluster analysis (HCA) and factor analysis (FA). Four factors were identified based on the loadings of PAHs and n-alkanes and were attributed to the following sources: (1) high-temperature combustion of fuels; (2) fugitive emissions from oil residues; (3) biogenic sources; and (4) unburned fuels. Multilinear regression (MLR) analysis was used to determine emission profiles and contributions of the sources. The reconstructed concentrations of particle phase aliphatic and polynuclear aromatic hydrocarbons were in good agreement (R2 > 0.70) with those measured in Santiago de Chile. PMID:11414034

Kavouras, I G; Koutrakis, P; Tsapakis, M; Lagoudaki, E; Stephanou, E G; Von Baer, D; Oyola, P

2001-06-01

55

Environmental aspects of PAH biodegradation  

Microsoft Academic Search

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants, some of which are on the US Environmental Protection Agency\\u000a priority pollutant list. Consequently, timely clean-up of contaminated sites is important. The lower-mol-wt PAHs are amenable\\u000a to bioremediation; however, higher-mol-wt PAHs seem to be recalcitrant to microbial degradation. The rates of biodegradation\\u000a of PAHs are highly variable and are dependent not only on

Kay L. Shuttleworth; E. Cerniglia

1995-01-01

56

Sources of PCDD/Fs, non-ortho PCBs and PAHs in sediments of high and low impacted transboundary rivers (Belgium-France).  

PubMed

PAHs, PCDD/Fs and non-ortho PCBs have been assessed in Yser and Upper-Scheldt river sediments. Higher contamination levels were observed in the Upper-Scheldt sediments: maximum concentrations for the 16 US-EPA PAHs, PCDD/Fs and non-ortho PCBs respectively amount to 8.9 mg kg(-1), 12 ng TEQ kg(-1) and 5.1 ng TEQ kg(-1). Diagnostic PAH ratios in sediments and atmospheric samples suggest that the PAH compounds are from pyrolytic origin, more specifically combustion processes. The huge consumption of coal in cokes-ovens and smelters and its use for house-heating in Northern France, although decreasing during the last decades, are in support of that suggestion. PCDD/F fingerprints in sediments and deposition material indicate that OCDD is the dominant congener. In addition use of pentachlorophenol (PCP) in the past led to a minor contribution of PCDD/Fs in our sediment samples. Non-ortho PCBs form a substantial fraction of the total TEQ concentrations observed in the sediments. Since the 1980s and 1990s a substantial reduction of the PCDD/F sediment concentrations is observed, but this is not the case for the PAHs. PMID:21741672

Sanctorum, Hermes; Elskens, Marc; Leermakers, Martine; Gao, Yue; Charriau, Adeline; Billon, Gabriel; Goscinny, Séverine; De Cooman, Ward; Baeyens, Willy

2011-07-08

57

Evaluating rapid diagnostic tests of intra-amniotic infection: Gram stain, amniotic fluid glucose level, and amniotic fluid to serum glucose level ratio  

Microsoft Academic Search

OBJECTIVE: The aim of the study was to compare the diagnostic utility of the Gram stain, the amniotic fluid glucose level, and the ratio of amniotic fluid glucose level to serum glucose level in detecting intra-amniotic infection.STUDY DESIGN: We conducted a prospective study of 127 patients with preterm labor and 26 patients with preterm premature rupture of the membranes (153

Michael J. Hussey; Edward S. Levy; Xavier Pombar; Peter Meyer; Howard T. Strassner

1998-01-01

58

PAH emission from a gasoline-powdered engine  

SciTech Connect

A gasoline powered engine operated on a dynamometer was used to investigate the PAH (Polycyclic Aromatic Hydrocarbons) emission. A 95-leadfree gasoline (95-LFG) and a premium leaded gasoline (PLG) were used as power-fuels. The engine was simulated for the idling condition and for the cruising speeds at 40, 80 and 110 km/hr. The concentrations of 21 individual PAHs in the engine exhaust, gasolines, and the ambient air were determined. Engine exhaust samples were collected by a PAH sampling system, while the ambient air sample was collected by using a standard PS-1 sampler. Twenty one individual PAHs were analyzed primarily by a gas chromatography/mass spectrometer (GC/MS). Naphthalene (Nap) has the highest concentration in the liquid phase of both 95-LFG and PLG, in which it accounts for respectively 98.3% and 76.6% of the total PAH. In terms of the mean fraction of the total PAHs entering the 95-LFG and PLG engines, the ambient air contributed less than 0.108% and 0.012%, respectively. Gasoline is the major PAH supplier for the automobile engine. By monitoring the PAH output/input mass ratios, the fuel combustion was found to be a generation process for 11 PAHs; and a depletion process for the rest 10 PAHs, in both 95-LFG and PLG powered engines. The mean emission factors of BaP were 2.92 and 2.47 {mu}g/km for 95-LFG and PLG powered engines, respectively. 11 refs., 12 tabs.

Mi, H.H.; Lee, W.J.; Wang, L.C.; Lin, T.A.; Chao, H.R. [National Cheng Kung Univ., Tainan (Taiwan, Province of China); Wu, T.L. [Nan-Tai College, Tainan (Taiwan, Province of China)

1996-09-01

59

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

PubMed

Due to the extensive amount of data suggesting the hazards of these compounds, 16 polycyclic aromatic hydrocarbons (PAHs) are on the Environmental Protection Agency (EPA) Priority Pollutant List. Emissions of these PAHs in the flue gas from the combustion of four coals were measured during four 1000h combustion runs using the 0.1MW heat-input (MWth) bench-scale fluidized bed combustor (FBC). An on-line sampling system was designed for the 16 PAHs, which consisted of a glass wool filter, condenser, glass fiber filter, Teflon filter, and a Tenax trap. The filters and Tenax were extracted by methylene chloride and hexane, respectively, followed by GC/MS analysis using the selective ion monitoring (SIM) mode. In this project, the effects of operating parameters, limestone addition, chlorine content in the coal, and Ca/S molar ratio on the emissions of PAHs were studied. The results indicated that the emissions of PAHs in an FBC system are primarily dependent on the combustion temperature and excess air ratio. The injection of secondary air with high velocity in the freeboard effectively reduces PAH emissions. The addition of extra limestone can promote the formation of PAHs in the FBC system. Chlorine in the coal can possibly lead to large benzene ring PAH formation during combustion. The total PAH emission increases with an increase in the sulfur content of coal. Incomplete combustion results in PAHs with four or more benzene rings. High efficiency combustion results in PAHs with two or three benzene rings. PMID:11406305

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

2001-06-29

60

Atmospheric deposition of polycyclic aromatic hydrocarbons (PAHs) to a coastal site of Hong Kong, South China  

NASA Astrophysics Data System (ADS)

Dry and wet deposition of atmospheric particles is a dominant pathway for PAHs to the coastal environments. Very few studies have been conducted to quantify the contribution of atmospheric deposition to PAH levels in the coastal regions. In this study, PAHs were analyzed in samples collected during a year-round campaign using atmospheric (gas and particle) and depositional samples at a coastal site South China. The average PAH particle deposition fluxes observed calculated 260 ± 190 ng m-2 d-1. Remarkable seasonal variations were recorded in the total PAH deposition fluxes, with higher deposition fluxes in the dry seasons and lower fluxes in the wet seasons. The temporal trend of deposition fluxes was influenced by PAH concentration in the aerosols and changes in meteorological parameters, such as temperature, rainfall, and wind speed etc. Dry deposition velocities of individual PAH compound ranged from 0.02 to 1.03 cm s-1, and there was a decrease pattern in dry deposition velocity with increasing molecular weight of PAHs. The annual mean washout ratio, defined as the ratio between the particle-associated concentrations of PAHs in precipitations and aerosols, was 3.4 × 105 in this study. Washout ratios decreased with increasing rainfall frequency and reached a consistent level afterward. The contribution of atmospheric deposition to PAH concentrations in the sediments was estimated to be 30%-40% in the coastal regions of South China.

Liu, Fobang; Xu, Yue; Liu, Junwen; Liu, Di; Li, Jun; Zhang, Gan; Li, Xiangdong; Zou, Shichun; Lai, Senchao

2013-04-01

61

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

PubMed

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. PMID:22885221

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

2012-08-10

62

Characteristics of particulate PAHs during a typical haze episode in Guangzhou, China  

NASA Astrophysics Data System (ADS)

The concentrations of polycyclic aromatic hydrocarbons (PAHs) in PM2.5 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 PM2.5 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.

Tan, Jihua; Guo, Songjun; Ma, Yongliang; Duan, Jingchun; Cheng, Yuan; He, Kebin; Yang, Fumo

2011-10-01

63

Distribution of PAHs in the northwestern part of the Japan Sea  

NASA Astrophysics Data System (ADS)

Surface water samples were collected at 13 stations in the Japan Sea and filtered through a glass fiber membrane (pore size 0.5 ?m). The vertical distribution of PAHs (nine points from depths between 2 m and 3300 m) were measured at one station. Thirteen PAHs having 3-6 rings in the dissolved and particulate phases were determined by HPLC with fluorescence detection. The mean concentration of total PAHs on the seawater surface was 8.5 ng/L. The mean concentrations in the dissolved and particulate phases for surface seawater were 5.6 ng/L and 2.7 ng/L, respectively. In the dissolved phase, 3-ring PAHs were the largest contributor, and 5-ring or more PAHs were in low ratio. Also, concentrations of PAHs in the particulate phase were dominated by 3-ring and 4-ring PAHs, but ratio of 3-ring PAHs was lower than in dissolved phase. Maximum of concentrations of PAHs in the dissolved (6.5 ng/L) and particulate (10.6 ng/L) phases were found for a depth 300 m. The possible source of PAHs is the atmosphere.

Chizhova, T.; Hayakawa, K.; Tishchenko, P.; Nakase, H.; Koudryashova, Yu.

2013-02-01

64

PAHs in the LMC and comparison to other galaxies  

NASA Astrophysics Data System (ADS)

We are studying the properties of the polycyclic aromatic emission features in a wide variety of environments across the Large Magellanic Clouds, in order to characterise the band ratio variations. The different PAH band ratios are known to vary in galaxies from source to source reflecting variations in local galactic environments. The strength of the PAH emission bands compared to other IR components also varies, reflecting variations in dust processing and illumination conditions. From a laboratory point of view there are several competing effects that determine the band ratios. These include the charge state of the molecules as well as possible local variations of chemical make-up of the PAH family effecting the shape of the bands. Sage-SPEC is a Spitzer/IRS mid-infrared spectroscopic study providing the unique possibility to study the environmental influence on the PAH emission features. In this study we present spectroscopic maps of HII regions, diffuse regions and molecular cloud regions covering a wide range of targets from relatively quiescent environments to the most actively star forming regions in the LMC. We have applied an advanced spatial rebinning scheme to be able main the maximum possible spatial resolution in bright regions, while averaging fainter regions in order to meet the required signal-to-noise-ratio. The main PAH band strengths have been obtained by fitting detailed model PAH feature profiles plus underlying continuum contribution to the observed spectra. The model profiles are derived high resolution mid-IR spectra and give better residuals than using Lorentzian profiles. We see ratios of the 7.7/11.3 um bands, for example, which span a range of a factor of 4 of the LMC. We see no effects of the band ratios as a function of radiation field hardness. The range of band ratios of diffuse regions clusters at the lower end of the band ratio range, while the HII regions tend to show higher 7.7/11.3 um band ratios, suggesting that variations of the band ratios are controlled by ionisation effects. We compare the range of band ratios seen within the LMC with the wide range of PAH band ratios seen in other galaxies to be able to lend more comprehensive interpretation on the use of the band ratios to trace radiation field density and other physical parameters.

Hony, S.; SAGE-Spec Team

2011-05-01

65

[Characteristics of PAHs in the atmosphere in winter and summer in the urban and suburban of Fuzhou].  

PubMed

Air samples from four sampling sites in urban and suburban in Fuzhou were collected by Hi-vol air samplers in winter and summer in 2010, and concentrations of PAHs were analyzed by GC-MSD. The total (particle and gas phase) PAHs concentrations in ambient air were in the range of 115.45-187.76 ng x m(-3) in winter and 45.55-59.20 ng x m(-3) in summer. PAHs in the gas phase were significantly higher than those in the particle phase, and PAHs in winter were higher than those in summer. No significantly difference was found between urban and suburban, with little higher PAHs in urban in winter and lower PAHs in summer. The ratios of PAHs in the gas phase to particle phase in summer were significantly higher than those in winter. The 2-4 rings PAHs were the dominant components in the gas phase while PAHs in the particle phase were dominated by 4-6 rings. The 3 rings PAHs were the dominant components in the gas phase in winter while 3 and 4 rings in summer. No significantly seasonal trends of PAHs components were found in the particle phase. The toxic equivalence factor (TEF) assessment showed that the pollution of PAHs in Fuzhou city was at a low level. Source analysis indicated that PAHs mainly came from combustion and diesel fuel was the predominant fuel in Fuzhou. PMID:23798099

Yi, Zhi-Gang; Huang, Xing-Ran; Bi, Jun-Qi; Guo, Ping-Ping; Zheng, Li-Li

2013-04-01

66

Matrix metalloproteinase-9 and the Cu/Zn ratio as ancillary diagnostic tools in distinguishing between the classical and follicular variants of papillary thyroid carcinoma.  

PubMed

The most common histological variants of papillary thyroid carcinoma (PTC), classical (CPTC) and follicular (FPTC), have different diagnostic features, molecular biology, and prognosis. Matrix metalloproteinase-9 (MMP-9) endopeptidase which degrades the components of the extracellular matrix is essential in the invasive growth and metastasizing of malignant tumors. The serum copper (Cu)/zinc (Zn) ratios are sensitive diagnostic and prognostic indicators in oncology since Cu- and Zn-dependent enzymes play important roles in the genesis and the progression of tumors. The aim of this study was to examine the expressions of MMP-9 in tissues of CPTC and FPTC, as well as to determine the Cu/Zn ratios in the same samples. MMP-9 was determined immunohistochemically, and the concentrations of copper and zinc in thyroid tissue were determined by means of flame atomic absorption spectrometry. The results obtained revealed significantly higher expressions of MMP-9 in CPTC in comparison with FPTC, as well as higher Cu/Zn ratios in CPTC than in FPTC. Thus, determining MMP-9 activities and the Cu/Zn ratios could improve the accuracy of the standard histopathological diagnosis of these two types of PTC. PMID:22528774

Dragutinovi?, Vesna V; Tati?, Svetislav B; Nikoli?-Mandi?, Snežana; Savin, Svetlana; Cveji?, Dubravka; Dun?erovi?, Duško; Gaji?, Milan; Paunovi?, Ivan

2012-04-12

67

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

National Technical Information Service (NTIS)

This data report documents monthly atmospheric CO2 mixing ratios and measurements obtained by analyzing individual flask air samples for the NOAA/CMDL global cooperative flask sampling network. Measurements include land-based sampling sites and shipboard ...

T. J. Conway P. P. Tans T. A. BBoden

1996-01-01

68

Electronic spectra of cationic PAH and PAH clusters  

NASA Astrophysics Data System (ADS)

An experiment designed for measuring the electronic spectra of PAH cations and PAH cluster cations has been set up, which is briefly described. The photodissociation spectra, reflecting the absorption spectra, of 2-methyl-naphthalene dimer cation have been recorded in the spectral ranges corresponding to the transitions from the ground state to both the excited charge resonance state and the first allowed local electronic excitation state.

Friha, H.; Féraud, G.; Pino, T.; Parneix, P.; Dhaouadi, Z.; Bréchignac, Ph.

2012-02-01

69

Perspective on Ecotoxicology of PAHs to Fish  

Microsoft Academic Search

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

Dennis T. Logan

2007-01-01

70

PAH and metal mixtures in New Orleans soils and sediments.  

PubMed

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

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

2001-12-17

71

PAH Emission From ULIRGs: Evidence For Unusual Grain Properties?  

NASA Astrophysics Data System (ADS)

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

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

2007-12-01

72

PAHs in Astronomy - A Review  

NASA Astrophysics Data System (ADS)

Carbonaceous materials play an important role in space. Polycyclic Aromatic Hydrocarbons (PAHs) are a ubiquitous component of organic matter in space. Their contribution is invoked in a broad spectrum of astronomical observations that range from the ultraviolet to the far-infrared and cover a wide variety of objects and environments from meteorites and interplanetary dust particles to outer Solar System bodies to the interstellar medium in the local Milky Way and in other galaxies. Extensive efforts have been devoted in the past two decades to experimental, theoretical, and observational studies of PAHs. A brief review is given here of the evidence obtained so far for the contribution of PAHs to the phenomena aforementioned. An attempt is made to distinguish the cases where solid evidence is available from cases where reasonable assumptions can be made to the cases where the presence - or the absence - of PAHs is purely speculative at this point.

Salama, Farid

2008-10-01

73

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

PubMed

The spatial and temporal distributions of polycyclic aromatic hydrocarbons (PAHs) in the Songhua River, Harbin, China, were investigated. Seventy-seven samples, 42 water and 35 sediment samples, were collected in April and October of 2007 and January of 2008. The concentrations of total PAHs in water ranged from 163.54 to 2,746.25 ng/L with the average value of 934.62 ng/L, which were predominated by 2- and 3-ring PAHs. The concentrations of total 16 PAHs in sediment ranged from 68.25 to 654.15 ng/g dw with the average value of 234.15 ng/g dw, which were predominated by 4-, 5- and 6-ring PAHs. Statistical analysis of the PAH concentrations shown that the highest concentrations of the total PAHs were found during rainy season (October of 2007) and the lowest during snowy season (January of 2008). Ratios of specific PAH compounds, including fluoranthene/(fluoranthene + pyrene) (Flu/(Flu + Pyr)) and phenanthrene/(phenanthrene + anthracene) (An/(Ant + PhA)), were calculated to evaluate the possible sources of PAH contaminations. These ratios reflected pyrolytic inputs of PAHs in Songhua River water and a mixed pattern of pyrolytic and petrogenic inputs of PAHs in the Songhua River sediments. Ecotoxicological risk levels calculated for PAHs suggested that there were individual PAHs, which can less frequently cause biological impairment in some samples, but no samples had constituents that may frequently cause biological impairment. Total toxic benzo[a]pyrene equivalent of ?cPAHs varied from 10.03 to 29.7 ng/g dw and from 0.36 to 1.92 ng/g dw for total toxic tetrachlorodibenzo-p-dioxin equivalent. The level of PAHs indicated a low toxicological risk to this area. PMID:23609889

Zhao, Xuesong; Ding, Jing; You, Hong

2013-04-23

74

X-ray Spectroscopy of the Radiation-Driven Winds of Massive Stars: Line Profile and Line Ratio Diagnostics  

SciTech Connect

Massive stars drive powerful, supersonic winds via the radiative momentum associated with the thermal UV emission from their photospheres. Shock phenomena are ubiquitous in these winds, heating them to millions, and sometimes tens of millions, of degrees. The emission line spectra from the shock-heated plasma provide powerful diagnostics of the winds' physical conditions, which in turn provide constraints on models of wind shock heating. Here I show how x-ray line transfer is affected by photoelectric absorption in the partially ionized component of the wind and how it can be modeled to determine the astrophysically important mass-loss rates of these stellar winds. I also discuss how photoexcitation out of metastable excited levels of helium-like ions can provide critical information about the location of the hot plasma in magnetically channeled massive star winds.

Cohen, David H. [Swarthmore College, Department of Physics and Astronomy, 500 College Ave., Swarthmore, PA 19081 (United States)

2009-09-10

75

Selecting a reduced suite of diagnostic ratios calculated between petroleum biomarkers and polycyclic aromatic hydrocarbons to characterize a set of crude oils.  

PubMed

A set of 34 crude oils was analysed by GC-MS (SIM mode) and a suite of 28 diagnostic ratios (DR) calculated. They involved 18 ratios between biomarker molecules (hopanes, steranes, diasteranes and triaromatic steroids) and 10 quotients between polycyclic aromatic hydrocarbons. Three unsupervised pattern recognition techniques (i.e., principal components analysis, heatmap hierarchical cluster analysis and Kohonen neural networks) were employed to evaluate the final dataset and, thus, ascertain whether the crude oils grouped as a function of their geographical origin. In addition, an objective variable selection procedure based on Procrustes Rotation was undertaken to select a reduced set of DR that comprised for most of the information in the original data without loosing relevant information. A reduced set of four DR (namely; TA21, D2/P2, D3/P3 and B(a)F/4-Mpy) demonstrated to be sufficient to characterize the crude oils and the groups they formed. PMID:21081235

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

2010-12-24

76

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

SciTech Connect

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

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

1996-02-01

77

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

PubMed

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

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

2011-09-19

78

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

PubMed Central

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

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

2011-01-01

79

Long-term fate of polycyclic aromatic hydrocarbons (PAH) in sediments from Loch Leven after closure of an aluminium smelter.  

PubMed

An aluminium smelter discharged polycyclic aromatic hydrocarbons (PAHs) into Loch Leven on the west of Scotland from 1907 until it closed in 2000, resulting in elevated PAH concentrations in the sediment. A temporal monitoring programme to investigate any recovery in sediment concentrations began in 2004, with sampling each year until 2008 and again in 2010. Cores were also collected to investigate temporal trends over a longer time scale and to estimate the sedimentation rate in the loch. The loch is divided into two basins, and PAH concentrations were significantly higher in the upper basin, closer to the smelter, than in the lower basin. The PAH distribution and concentration ratios were consistent with a pyrolytic source of PAHs, with a high proportion of heavier parent PAHs. There was no evidence of any recovery in PAH concentrations, perhaps due to the mixing and disturbances of the sediment, and the persistence of PAHs. Concentrations of all PAHs were above the Background Assessment Concentrations (BACs) in both basins. In the lower basin only the 5- and 6-ring PAHs were above the Effects Range Low (ERL) values, but in the upper basin all but naphthalene were above the ERLs. There is therefore still an unacceptable risk of chronic effects in marine species. Concentrations decreased down the cores, falling below BACs in the deepest sections. However, ERLs were exceeded as far down the core as 30 cm for some PAHs. PMID:22510879

McIntosh, A D; Fryer, R J; Webster, L; Cundy, A B

2012-04-18

80

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

Microsoft Academic Search

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

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

2011-01-01

81

Original Article Determination of the efficacy of FEV 6 as a surrogate for FVC in the diagnostic screening for chronic obstructive pulmonary disease through the comparison of FEV 1 \\/FVC and FEV 1 \\/FEV 6 ratios  

Microsoft Academic Search

Objective: To determine the efficacy of using forced expiratory volume in six seconds (FEV 6 ) as a surrogate for forced vital capacity (FVC) in the diagnostic screening for chronic obstructive pulmonary disease (COPD) by comparing FEV 1 \\/FVC ratios with FEV 1 \\/FEV 6 ratios. Methods: In November of 2003, on World COPD Day, we conducted a campaign of

Marília Montenegro Cabral; Liana Gonçalves de Macedo; Marta de Andrade; Lima Coelho; Ana Lúcia; Pereira Lima; Alves Dias

2007-01-01

82

Is albumin gradient or fluid to serum albumin ratio better than the pleural fluid lactate dehydroginase in the diagnostic of separation of pleural effusion?  

PubMed Central

Background To determine the accuracy of serum-effusion albumin gradient (SEAG) and pleural fluid to serum albumin ratio (ALBR) in the diagnostic separation of pleural effusion into transudate and exudate and to compare SEAG and ALBR with pleural fluid LDH (FLDH) the most widely used test. Methods Data collected from 200 consecutive patients with a known cause of pleural effusion in a United Kingdom district general hospital. Results The median and inter quartile ranges (IQR) for SEAG 93.5 (33.8 to 122.5) g/dl, ALBR 0.49 (0.42 to 0.62) and FLDH 98.5 IU/L(76.8 to 127.5) in transudates were significantly lower than the corresponding values for exudates 308.5 (171 to 692), 0.77 (0.63 to 0.85), 344 (216 to 695) all p < 0.0001. The Area Under the Curve (AUC) with 95% confidence intervals (Cl) for SEAG, ALBR and FLDH were 0.81 (0.75 to 0.87), 0.79 (0.72 to 0.86) and 0.9 (0.87 to 0.96) respectively. The positive likelihood ratios with 95%CI for FLDH, SEAG, and ALBR were: 7.3(3.5–17), 6.3(3–15) 6.2(3–14) respectively. There was a significant negative correlation between SEAG and ALBR (r= -0.89, p < 0.0001). Conclusion The discriminative value for SEAG and ALBR appears to be similar in the diagnostic separation of transudates and exudates. FLDH is a superior test compared to SEAG and ALBR.

Joseph, Jose; Badrinath, Padmanabhan; Basran, Gurnam S; Sahn, Steven A

2002-01-01

83

Investigating PAH relative reactivity using congener profiles, quinone measurements and back trajectories  

NASA Astrophysics Data System (ADS)

Vapour and particle-associated concentrations of 15 polycyclic aromatic hydrocarbons (PAH) and 11 PAH quinones have been measured in winter and summer campaigns at the rural site, Weybourne in eastern England. Concentrations of individual PAH are 20-140 times smaller than average concentrations at an English urban site. The concentrations of PAH are greatest in air masses originating from southern England relative to those from Scandinavia and the North Atlantic, while quinone to parent PAH ratios show an inverse behaviour, being highest in the more aged North Atlantic polar air masses. While concentration of 1,2-naphthoquinone decline from summer to winter, those of 1,4-naphthoquinone and anthraquinone increase suggesting a photochemical formation pathway. A comparison of congener concentration profiles measured at Weybourne with those from an urban source area (Birmingham) reveals differential losses at the rural site, especially evident in fluoranthene: pyrene ratios and consistent with the known rates of vapour phase reactions of 3 and 4 ring compounds with hydroxyl radical. The ratios of quinones to their parent PAH at Weybourne are greater than those in the urban source area indicating either more rapid loss processes for PAH, or formation of quinones during advection of the air mass, or probably both.

Alam, M. S.; Delgado-Saborit, J. M.; Stark, C.; Harrison, R. M.

2013-10-01

84

Occupational PAH Exposures during Prescribed Pile Burns  

Microsoft Academic Search

Wildland firefighters are exposed to particulate matter and gases containing polycyclic aro- matic hydrocarbons (PAHs), many of which are known carcinogens. Our objective was to eval- uate 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

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

2008-01-01

85

Pyroelectric array horizon sensor (PAHS)  

Microsoft Academic Search

A linear pyroelectric detector array has been chosen for the application of an inexpensive earth sensor in the 14- to 16-micron range. The PAHS makes use of a modular design to allow flexibility in spacecraft mounting and mission profiles. The simplicity of the earth radiance measurement allows a variety of pitch and roll computation algorithms. These computations may be performed

Martin Vasey; Chris Clark

1990-01-01

86

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

SciTech Connect

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

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

2012-01-15

87

Isolation of adherent polycyclic aromatic hydrocarbon (PAH)-degrading bacteria using PAH-sorbing carriers  

Microsoft Academic Search

Two different procedures were compared to isolate polycyclic aromatic hydrocarbon (PAH)-utilizing bacteria from PAH-contaminated soil and sludge samples, i.e., (i) shaken enrichment cultures in liquid mineral medium in which PAHs were supplied as crystals and (ii) a new method in which PAH degraders were enriched on and recovered from hydrophobic membranes containing sorbed PAHs. Both techniques were successful, but selected

LEEN BASTIAENS; DIRK SPRINGAEL; PIERRE WATTIAU; HAUKE HARMS; RUPERT DEWACHTER; HUBERT VERACHTERT; LUDO DIELS

2000-01-01

88

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

PubMed

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

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

2011-07-06

89

Pattern, sources and toxic potential of PAHs in the agricultural soils of Delhi, India.  

PubMed

Surface soil (0-5 cm) from various agricultural sites in Delhi was analyzed to discern the contents of 16 priority polycyclic aromatic hydrocarbons (PAHs). Reference and deuterated standards were used for identification and quantification of PAHs by high performance liquid chromatography (HPLC) with UV detection. summation operator(16)PAHs ranged from 830 to 3880 microg kg(-1) (dry wt.) with an arithmetic mean of 1910+/-1020 microg kg(-1) summation operator(16)PAHs values at the urban sites were 2-5 times higher as compared to the rural sites. In general, low molecular weight PAHs were predominant. Total organic carbon (TOC) was found to be significantly correlated with summation operator(16)PAHs. Isomer pair ratios and Principal component analysis (PCA) suggested biomass and fossil fuel combustion as the main sources of PAHs. The toxic equivalency factors (TEFs) were used to estimate benzo[a]pyrene-equivalent concentration (B[a]P(eq)). Therewith, PAH content of urban agricultural soil was found to have more carcinogenic potential. PMID:18757133

Agarwal, Tripti; Khillare, P S; Shridhar, Vijay; Ray, Sharmila

2008-07-23

90

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

PubMed

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 (?10 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. PMID:23485234

Karaca, Gizem; Tasdemir, Yucel

2013-01-01

91

Occupational PAH exposures during prescribed pile burns.  

PubMed

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

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

2008-05-31

92

Indices of PAH Origin—A Case Study of the Gulf of Gda?sk (SE Baltic) Sediments  

Microsoft Academic Search

The aim of this work is to present a way of developing indices for assessing the dominant origin of polycyclic aromatic hydrocarbons (PAHs) on the basis of a case study in the Gulf of Gda?sk (SE Baltic). The indices were based on selected concentration ratios of both parent and alkylated PAHs found in reference matrices that are potential anthropogenic sources

LUDWIK LUBECKI; GRA?YNA KOWALEWSKA

2012-01-01

93

Manganese sulfate effect on PAH formation from polystyrene pyrolysis  

Microsoft Academic Search

Polystyrene (PS) was pyrolyzed with\\/without manganese sulfate addition in a 100% N2 environment at 600, 700 and 800°C in a laboratory quartz reactor. The mole ratio of carbon (in PS) to Mn was 40\\/1. The gas-phase and liquid-phase polycyclic aromatic hydrocarbons (PAHs) were extracted with dichloromethane (DCM) and subsequently prepared for further analysis with an HPLC equipped with a wavelength-scanning

Yu-Ling Wei; Jen-Ho Lee

1999-01-01

94

A computer program for fast non-LTE analysis of interstellar line spectra. With diagnostic plots to interpret observed line intensity ratios  

NASA Astrophysics Data System (ADS)

Aims:The large quantity and high quality of modern radio and infrared line observations require efficient modeling techniques to infer physical and chemical parameters such as temperature, density, and molecular abundances. Methods: We present a computer program to calculate the intensities of atomic and molecular lines produced in a uniform medium, based on statistical equilibrium calculations involving collisional and radiative processes and including radiation from background sources. Optical depth effects are treated with an escape probability method. The program is available on the World Wide Web at http://www.sron.rug.nl/~vdtak/radex/index.shtml. The program makes use of molecular data files maintained in the Leiden Atomic and Molecular Database (LAMDA), which will continue to be improved and expanded. Results: The performance of the program is compared with more approximate and with more sophisticated methods. An Appendix provides diagnostic plots to estimate physical parameters from line intensity ratios of commonly observed molecules. Conclusions: This program should form an important tool in analyzing observations from current and future radio and infrared telescopes. Appendices A-D, are only available in electronic form at http://www.aanda.org

van der Tak, F. F. S.; Black, J. H.; Schöier, F. L.; Jansen, D. J.; van Dishoeck, E. F.

2007-06-01

95

Diurnal cycle of PAHs, nitro-PAHs, and oxy-PAHs in a high oxidation capacity marine background atmosphere.  

PubMed

To improve our understanding of the formation and fate of nitro-PAHs, which contribute to the toxicity of ambient particles, the diurnal variation of their ambient concentration was studied concurrently with the corresponding PAH, OH radical, ozone, and oxy-PAH concentration, during an intensive field campaign at an eastern Mediterranean marine background location (Finokalia, Island of Crete) in August, 2001. The gas-phase PAH and OH radical concentrations maximized at noon. Gas-phase PAH concentrations were correlated (p < 0.001) with ambient temperatures. The gas-phase OH-radical-initiated PAH reaction was identified as the major process contributing to the ambient burden of nitro-PAHs. 2-Nitrofluoranthene and 2-nitropyrene were the most abundant particle-associated nitro-PAHs. A well-defined diurnal pattern was identified for both compounds exhibiting a maximum during midday followed by a rapid decrease. 9,10-Anthracenodione and 9-fluorenone, the most abundant oxy-PAHs, did not present a diurnal variation of concentration. PMID:18186330

Tsapakis, Manolis; Stephanou, Euripides G

2007-12-01

96

Variation in PAH patterns in road runoff.  

PubMed

Twelve particle-bound polycyclic aromatic hydrocarbons (PAHs) were measured in the first flush regime of road runoff during nine events in Winterthur in Switzerland. The total PAH contents ranged from 17 to 62 ?g/g. The PAH patterns measured at different time intervals during the first flush periods were very similar within each event irrespective of variation in suspended solids (SS) concentration within the first flush regime. However, the PAH patterns were different from event to event. This indicates that the environment plays an important role in PAH accumulation in SS. A toxicity identification evaluation approach using a toxicity equivalency factor (TEF) was applied to compare toxicities in the different events. The TEFs were found to be between 8 and 33 ?g TEQ g(-1) (TEQ: toxic equivalent concentration). In some cases, two events having similar total PAH contents showed two fold toxicity differences. PMID:23787306

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

2013-01-01

97

Hydroxynitro-PAH and Other PAH Derivatives in California's Atmosphere and Their Contribution to Ambient Mutagenicity.  

National Technical Information Service (NTIS)

Nitro-PAH lactones formed in the air by reactions of polycyclic aromatic hydrocarbons (PAHs) and nitrogen oxide gases, may be responsible for a significant portion of the mutagenicity of particulate matter present in California's atmosphere. Simulating am...

R. Atkinson J. Arey

1991-01-01

98

PAH emission from various industrial stacks  

Microsoft Academic Search

The emission of polycyclic aromatic hydrocarbons (PAHs) from various industrial stacks (blast furnace, basic oxygen furnace, coke oven, electric arc furnace, heavy oil plant, power plant and cement plant) in southern Taiwan were investigated. PAH concentrations (?g\\/N m3) and PAH emission factors (?g\\/kg feedstock) were determined. In addition to these eight stationary industrial stacks, an industrial waste incinerator, a diesel

Hsi-Hsien Yang; Wen-Jhy Lee; Shui-Jen Chen; Soon-Onn Lai

1998-01-01

99

Multimedia Analysis of PAHs and Nitro-PAH Daughter Products in the Los Angeles Basin  

Microsoft Academic Search

ABSTRACT Polycyclic aromatic hydrocarbons,(PAHs) are toxic air pollutants which are formed during the incomplete combustion of organic materials. In the atmosphere, PAHs partition between the gas and particulate phases. PAHs which exist in the gas phase can react with hydroxy,radicals and gaseous nitrate radicals, in the presence of NOx, to form nitro-PAH derivatives. The available literature data suggest that some

Denise Yaffe; Yoram Cohen; Janet Arey; Andrew J. Grosovsky

2001-01-01

100

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

PubMed

The concentration of polycyclic aromatic hydrocarbons (PAHs) and the toxicity to marine bacteria (Vibrio fischeri) were measured for the organic solvent extracts of sea sediments collected from an urban watershed area (Hiroshima Bay) of Japan and compared with the concentrations and toxicity of atmospheric particulate matter (PM). In atmospheric PM, the PAHs concentration was highest in fine particulate matter (FPM) collected during cold seasons. The concentrations of sea sediments were 0.01-0.001 times those of atmospheric PM. 1/EC50 was 1-10 L g(-1) PM for atmospheric PM and 0.1-1 L g(-1) dry solids for sea sediments. These results imply that toxic substances from atmospheric PM are diluted several tens or hundreds of times in sea sediments. The ratio of the 1/EC50 to PAHs concentration ((1/EC50)/16PAHs) was stable for all sea sediments (0.1-1 L ?g(-1) 16PAHs) and was the same order of magnitude as that of FPM and coarse particulate matter (CPM). The ratio of sediments collected from the west was more similar to that of CPM while that from the east was more similar to FPM, possibly because of hydraulic differences among water bodies. The PAHs concentration pattern analyses (principal component analysis and isomer ratio analysis) were conducted and the results showed that the PAHs pattern in sea sediments was quite different to that of FPM and CPM. Comparison with previously conducted PAHs analyses suggested that biomass burning residues comprised a major portion of these other sources. PMID:22797225

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

2012-01-01

101

Pulmonary arterial hypertension in children: Diagnostic work-up and challenges  

PubMed Central

The diagnostic evaluation of a pediatric patient with suspected pulmonary arterial hypertension (PAH) is extensive but essential, given the rapid progression of the disease if left undiagnosed and untreated. The major goals of performing a complete diagnostic work-up are to confirm the diagnosis of PAH, assess disease severity, rule out associated diseases, and begin to formulate an individualized treatment plan for the pediatric patient with pulmonary hypertension. This article will provide a comprehensive review of the diagnostic work-up of the child with suspected PAH as well as a review of some of the challenges faced when assessing a child for PAH.

Rosenzweig, E.B.; Feinstein, J.A.; Humpl, T.; Ivy, D.D.

2011-01-01

102

Phenols and hydroxy-PAHs (arylphenols) as tracers for coal smoke particulate matter: source tests and ambient aerosol assessments  

SciTech Connect

Source tests were conducted to analyze and characterize diagnostic key tracers for emissions from burning of coals with various ranks. Coal samples included lignite from Germany, semibituminous coal from Arizona, USA, bituminous coal from Wales, UK and sample from briquettes of semibituminous coal, bituminous coal and anthracite from China. Ambient aerosol particulate matter was also collected in three areas of China and a background area in Corvallis, OR (U.S.) to confirm the presence of tracers specific for coal smoke. The results showed a series of aliphatic and aromatic hydrocarbons and phenolic compounds, including PAHs and hydroxy-PAHs as the major tracers, as well as a significant unresolved complex mixture (UCM) of compounds. The tracers that were found characteristic of coal combustion processes included hydroxy-PAHs and PAHs. Atmospheric ambient samples from Beijing and Taiyuan, cities where coal is burned in northern China, revealed that the hydroxy-PAH tracers were present during the wintertime, but not in cities where coal is not commonly used (e.g., Guangzhou, South China). Thus, the mass of hydroxy-PAHs can be apportioned to coal smoke and the source strength modeled by summing the proportional contents of EC (elemental carbon), PAHs, UCM and alkanes with the hydroxy-PAHs. 36 refs., 2 figs., 3 tabs.

Bernd R.T. Simoneit; Xinhui Bi; Daniel R. Oros; Patricia M. Medeiros; Guoying Sheng; Jiamo Fu [Oregon State University, Corvallis, OR (United States). Environmental Sciences Program

2007-11-01

103

Biodegradation of polycyclic aromatic hydrocarbons (PAHs) by Cladosporium sphaerospermum isolated from an aged PAH contaminated soil  

Microsoft Academic Search

The ability of a Deuteromycete fungus, Cladosporium sphaerospermum, previously isolated from soil of an aged gas manufacturing plant, to degrade polycyclic aromatic hydrocarbons was investigated. This strain was able to degrade PAHs in non-sterile soils (average 23%), including high molecular weight PAHs, after 4 weeks of incubation. In a microcosm experiment, PAH depletion was clearly correlated to fungal establishment. In

Olivier Potin; Etienne Veignie; Catherine Rafin

2004-01-01

104

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

Microsoft Academic Search

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

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

1996-01-01

105

Development of new source diagnostic methods and variance reduction techniques for Monte Carlo eigenvalue problems with a focus on high dominance ratio problems  

NASA Astrophysics Data System (ADS)

Obtaining the solution to the linear Boltzmann equation is often is often a daunting task. The time-independent form is an equation of six independent variables which cannot be solved analytically in all but some special problems. Instead, numerical approaches have been devised. This work focuses on improving Monte Carlo methods for its solution in eigenvalue form. First, a statistical method of stationarity detection called the KPSS test adapted as a Monte Carlo eigenvalue source convergence test. The KPSS test analyzes the source center of mass series which was chosen since it should be indicative of overall source behavior, and is physically easy to understand. A source center of mass plot alone serves as a good visual source convergence diagnostic. The KPSS test and three different information theoretic diagnostics were implemented into the well known KENOV.a code inside of the SCALE (version 5) code package from Oak Ridge National Laboratory and compared through analysis of a simple problem and several difficult source convergence benchmarks. Results showed that the KPSS test can add to the overall confidence by identifying more problematic simulations than without its usage. Not only this, the source center of mass information on hand visually aids in the understanding of the problem physics. The second major focus of this dissertation concerned variance reduction methodologies for Monte Carlo eigenvalue problems. The CADIS methodology, based on importance sampling, was adapted to the eigenvalue problems. It was shown that the straight adaption of importance sampling can provide a significant variance reduction in determination of keff (in cases studied up to 30%?). A modified version of this methodology was developed which utilizes independent deterministic importance simulations. In this new methodology, each particle is simulated multiple times, once to every other discretized source region utilizing the importance for that region only. Since each particle is simulated multiple times, this methodology often slows down the final keff convergence, but an increase coupling between source zones with important yet low probability interaction is observed. This is an important finding for loosely coupled systems and may be useful in their analysis. The third major focus of this dissertation concerns the use of the standard cumulative fission matrix methodology for high dominance ratio problems which results in high source correlation. Source eigenvector confidence is calculated utilizing a Monte Carlo iterated confidence approach and shown to be superior to the currently used plus and minus fission matrix methodology. Utilizing the fission matrix based approach with appropriately meshing and particle density, it is shown that the fission matrix elements tend to be independent. As a result, the keff and the source eigenvector can be calculated without bias, which is not the case for the standard methodology due to the source correlation. This approach was tested with a 1-D multigroup eigenvalue code developed for this work. A preliminary automatic mesh and particle population diagnostic were formulated to ensure independent and normal fission matrix elements. The algorithm was extended in parallel to show the favorable speedup possible with the fission matrix based approach. (Full text of this dissertation may be available via the University of Florida Libraries web site. Please check http://www.uflib.ufl.edu/etd.html)

Wenner, Michael T.

106

Sorptive behavior of nitro-PAHs in street runoff and their potential as indicators of diesel vehicle exhaust particles.  

PubMed

This is the first report to reveal the particle-water distribution of nitropolycyclic aromatic hydrocarbons (NPAHs) and to discuss their potential risks and utility as indicators of diesel vehicle exhaust particles (DEP). Time-series samples of runoff were collected from a highway, and NPAHs and polycyclic aromatic hydrocarbons (PAHs) were determined by gas chromatography-mass spectrometry (GC-MS) to study their dynamic behavior. The concentrations of total NPAHs ranged from 11 to 73 ng/L in particulate phase (>0.7 mcirom) and from 2.3 to 4.9 ng/L in dissolved phase (<0.7 microm). Like their PAH analogs, most (81-97%) NPAHs were associated with particulate matter. The organic carbon-normalized in situ partition coefficients (Koc') of NPAHs observed in runoff events (10(5.8-6.3) for 2-nitrofluoranthene and 10(5.8-6.2) for 1-nitropyrene [1-NP]) were more than 1 order of magnitude higher than those expected from their Kow, indicating great affinity for particulate matter such as soot. Concentrations of PAHs and NPAHs adjusted by potency equivalency factors and induction equivalency factors showed that the potential risks of NPAHs were smaller than those of PAHs by a factor of more than a hundred for the particulate phase and morethan fourforthe dissolved phase. Comparison of concentrations and compositions of NPAHs and PAHs among runoff, DEP, gasoline vehicle exhaust particles, boiler exhaust particles, and aerosols suggested that the ratio of 1-NP to total PAHs (1-NP/PAH) is a useful indicator of DEP for source apportionment of PAHs among traffic-related sources. Source-apportionment of PAHs in the runoff by 1-NP/PAH and methylphenanthrene/phenanthrene ratios suggested that most PAHs in the runoff except the second flush peak were derived from DEP but that other pyrogenic sources contributed to the particles at the second flush and thus to the overall runoff particles. PMID:18351085

Murakami, Michio; Yamada, Junya; Kumata, Hidetoshi; Takada, Hideshige

2008-02-15

107

The relationship between prenatal exposure to airborne polycyclic aromatic hydrocarbons (PAHs) and PAH-DNA adducts in cord blood.  

PubMed

In a birth cohort study, we have assessed the dose-response relationship between individual measurements of prenatal airborne polycyclic aromatic hydrocarbon (PAH) exposure and specific PAH-DNA adducts in cord blood adjusted for maternal blood adducts and season of birth. The study uses data from an earlier established birth cohort of children in Krakow. The final analysis included 362 pregnant women who gave birth to term babies and had complete data on personal exposure in the second trimester of pregnancy to eight airborne PAHs including benzo[a]pyrene (B[a]P), as well as DNA adducts, both in maternal and cord blood. The relation between cord blood PAH-DNA adducts and airborne prenatal PAH exposure was non-linear. Although cord blood PAH-DNA adducts were significantly associated with the B[a]P exposure categorized by tertiles (non-parametric trend z=3.50, P<0.001), the relationship between B[a]P and maternal blood adducts was insignificant (z=1.63, P=0.103). Based on the multivariable linear regression model, we estimated the effect of the prenatal airborne B[a]P on the level of cord blood adducts. In total, 14.8% of cord blood adducts variance was attributed to the level of maternal adducts and 3% to a higher prenatal B[a] exposure above 5.70?ng/m(3). The calculated fetal/maternal blood adduct ratio (FMR) linearly increased with B[a]P exposure (z=1.99, P=0.047) and was highest at B[a]P concentrations exceeding 5.70?ng/m(3). In conclusion, the results support other findings that transplacental exposure to B[a]P from maternal inhalation produces DNA damage in the developing fetus. It also confirms the heightened fetal susceptibility to prenatal PAH exposure that should be a matter of public health concern, particularly in the highly polluted areas, because DNA adducts represent a pro-carcinogenic alteration in DNA. The continuation of this birth cohort study will assess the possible health effects of fetal DNA damage on the health of children and help in establishing new protective guidelines for newborns. PMID:23299301

Jedrychowski, Wieslaw A; Perera, Frederica P; Tang, Deliang; Rauh, Virginia; Majewska, Renata; Mroz, Elzbieta; Flak, Elzbieta; Stigter, Laura; Spengler, John; Camann, David; Jacek, Ryszard

2013-01-09

108

THE RELATIONSHIP BETWEEN PRENATAL EXPOSURE TO AIRBORNE POLYCYCLIC AROMATIC HYDROCARBONS (PAH) AND PAH-DNA ADDUCTS IN CORD BLOOD  

PubMed Central

In a birth cohort study, we have assessed the dose-response relationship between individual measurements of prenatal airborne PAH exposure and specific PAH-DNA adducts in cord blood adjusted for maternal blood adducts and season of birth. The study uses data from an earlier established birth cohort of children in Krakow. The final analysis included 362 pregnant women who gave birth to term babies and had complete data on personal exposure in the second trimester of pregnancy to eight airborne polycyclic aromatic hydrocarbons (PAH) including benzo[a]pyrene (B[a]P), as well as DNA adducts, both in maternal and cord blood. The relation between cord blood PAH-DNA adducts and airborne prenatal PAH exposure was non-linear. While cord blood PAH-DNA adducts were significantly associated with the B[a]P exposure categorized by tertiles (nonparametric trend z = 3.50, p < 0.001), the relationship between B[a]P and maternal blood adducts was insignificant (z = 1.63, p = 0.103). Based on the multivariable linear regression model we estimated the effect of the prenatal airborne B[a]P on the level of cord blood adducts. In total, 14.8% of cord blood adducts variance was attributed to the level of maternal adducts and 3% to a higher prenatal B[a] exposure above 5.70 ng/m3. The calculated fetal/maternal blood adducts ratio (FMR) linearly increased with the B[a]P exposure (z = 1.99, p = 0.047) and was highest at B[a]P concentrations exceeding 5.70 ng/m3. In conclusion, the results support other findings that transplacental exposure to B[a[P from maternal inhalation produces DNA damage in the developing fetus. It also confirms the heightened fetal susceptibility to prenatal PAH exposure that should be a matter of public health concern particularly in the highly polluted areas because DNA adducts represent a pro-carcinogenic alteration in DNA The continuation of this birth cohort study will assess the possible health effects of fetal DNA damage on health of children and help in establishing new protective guidelines for newborns.

Jedrychowski, Wieslaw; Perera, Frederica P.; Tang, Deliang; Rauh, Virginia; Majewska, Renata; Mroz, Elzbieta; Flak, Elzbieta; Stigter, Laura; Spengler, John; Camann, David; Jacek, Ryszard

2013-01-01

109

Polycyclic aromatic hydrocarbons (PAHs), nitrated PAHs and oxygenated PAHs in ambient air of the Marseilles area (South of France): concentrations and sources.  

PubMed

Ambient measurements (gas+particle phases) of 15 polycyclic aromatic hydrocarbons (PAHs), 17 nitrated PAHs (NPAHs) and 9 oxygenated PAHs (OPAHs) were carried out during July 2004 on three different sites (urban, sub-urban and rural) in the region of Marseilles (South of France). Atmospheric concentrations of these classes of polyaromatics are great of interest because of their high potential mutagenicity and carcinogenicity. OPAH concentrations were of the same order of magnitude as those of PAHs while NPAH concentrations were one to two orders lower. 9-Fluorenone and 9,10-anthraquinone were the most abundant OPAHs, accounting for about 60% and 20% of the total OPAH concentration. Respectively 1-and 2-nitronaphthalene were the most abundant NPAHs and were accounting for about 30-50% and 15-30% of the total NPAH concentration. NPAHs and OPAHs concentration levels were consistent with the characteristics of the sampling sites. Study of source specific ratios (2-nitrofluoranthene/1-nitropyrene) clearly showed those primary NPAH sources influence the urban and sub-urban sites whereas production of secondary NPAHs by gas phase reactions was prevalent at the rural site. The study of NPAH and OPAH sources suggested that gasoline engines were an important source of such compounds Whereas the dominant source of 1-nitropyrene, 2-nitrofluorene, 6-nitrochrysene and benz[a]anthracene-7,12-dione seems to be diesel vehicles. Finally, 9,10-anthraquinone presents a double origin: primary diesel emission and photochemical processes. Formation of 9,10-anthraquinone from anthracene ozonation was shown at the rural site. Further investigations will be necessary in order to discriminate when (before or during the sampling) the OPAHs are formed. PMID:17590415

Albinet, Alexandre; Leoz-Garziandia, Eva; Budzinski, Hélène; Viilenave, Eric

2007-06-27

110

Diagnostic accuracy of spot urinary protein and albumin to creatinine ratios for detection of significant proteinuria or adverse pregnancy outcome in patients with suspected pre-eclampsia: systematic review and meta-analysis  

PubMed Central

Objective To determine the diagnostic accuracy of two “spot urine” tests for significant proteinuria or adverse pregnancy outcome in pregnant women with suspected pre-eclampsia. Design Systematic review and meta-analysis. Data sources Searches of electronic databases 1980 to January 2011, reference list checking, hand searching of journals, and contact with experts. Inclusion criteria Diagnostic studies, in pregnant women with hypertension, that compared the urinary spot protein to creatinine ratio or albumin to creatinine ratio with urinary protein excretion over 24 hours or adverse pregnancy outcome. Study characteristics, design, and methodological and reporting quality were objectively assessed. Data extraction Study results relating to diagnostic accuracy were extracted and synthesised using multivariate random effects meta-analysis methods. Results Twenty studies, testing 2978 women (pregnancies), were included. Thirteen studies examining protein to creatinine ratio for the detection of significant proteinuria were included in the multivariate analysis. Threshold values for protein to creatinine ratio ranged between 0.13 and 0.5, with estimates of sensitivity ranging from 0.65 to 0.89 and estimates of specificity from 0.63 to 0.87; the area under the summary receiver operating characteristics curve was 0.69. On average, across all studies, the optimum threshold (that optimises sensitivity and specificity combined) seems to be between 0.30 and 0.35 inclusive. However, no threshold gave a summary estimate above 80% for both sensitivity and specificity, and considerable heterogeneity existed in diagnostic accuracy across studies at most thresholds. No studies looked at protein to creatinine ratio and adverse pregnancy outcome. For albumin to creatinine ratio, meta-analysis was not possible. Results from a single study suggested that the most predictive result, for significant proteinuria, was with the DCA 2000 quantitative analyser (>2 mg/mmol) with a summary sensitivity of 0.94 (95% confidence interval 0.86 to 0.98) and a specificity of 0.94 (0.87 to 0.98). In a single study of adverse pregnancy outcome, results for perinatal death were a sensitivity of 0.82 (0.48 to 0.98) and a specificity of 0.59 (0.51 to 0.67). Conclusion The maternal “spot urine” estimate of protein to creatinine ratio shows promising diagnostic value for significant proteinuria in suspected pre-eclampsia. The existing evidence is not, however, sufficient to determine how protein to creatinine ratio should be used in clinical practice, owing to the heterogeneity in test accuracy and prevalence across studies. Insufficient evidence is available on the use of albumin to creatinine ratio in this area. Insufficient evidence exists for either test to predict adverse pregnancy outcome.

2012-01-01

111

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

PubMed

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

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

2011-02-25

112

Effect of organic wastes on the plant-microbe remediation for removal of aged PAHs in soils.  

PubMed

The effectiveness of in-situ bioremediation of polycyclic aromatic hydrocarbons (PAHs) may be inhibited by low nutrients and organic carbon. To evaluate the effect of organic wastes on the PAHs removal efficiency of a plant-microbe remediation system, contaminated agricultural soils were amended with different dosages of sewage sludge (SS) and cattle manure (CM) in the presence of alfalfa (Medicago sativa L.) and PAHs-degraders (Bacillus sp. and Flavobacterium sp.). The results indicated that the alfalfa mean biomasses varied from 0.56 to 2.23 g/pot in root dry weight and from 1.80 to 4.88 g/pot in shoot dry weight. Low dose amendments, with rates of SS at 0.1% and CM at 1%, had prominent effects on plant growth and soil PAHs degradation. After 60-day incubation, compared with about 5.6% in the control, 25.8% PAHs removal was observed for treatments in the presence of alfalfa and PAHs-degraders; furthermore, when amended with different dosages of SS and CM, the removed PAHs from soils increased by 35.5%-44.9% and 25.5%-42.3%, respectively. In particular, the degradation of high-molecular-weight PAHs was up to 42.4%. Dehydrogenase activities (DH) ranged between 0.41 and 1.83 microg triphenylformazan/(g dry soil x hr) and the numbers of PAHs-degrading microbes (PDM) ranged from 1.14 x 10(6) to 16.6 x 10(6) most-probable-number/g dry soil. Further investigation of the underlying microbial mechanism revealed that both DH and PDM were stimulated by the addition of organic wastes and significantly correlated with the removal ratio of PAHs. In conclusion, the effect of organic waste application on soil PAHs removal to a great extent is dependent on the interactional effect of nutrients and dissolved organic matter in organic waste and soil microorganisms. PMID:23513690

Zhang, Jing; Lin, Xiangui; Liu, Weiwei; Wang, Yiming; Zeng, Jun; Chen, Hong

2012-01-01

113

Concentration and photochemistry of PAHs, NPAHs, and OPAHs and toxicity of PM2.5 during the Beijing Olympic Games.  

PubMed

Atmospheric particulate matter with diameter <2.5 um (PM(2.5)) was collected at Peking University (PKU) in Beijing, China before, during, and after the 2008 Olympics and analyzed for black carbon (BC), organic carbon (OC), lower molecular weight (MW < 300) and MW302 Polycyclic Aromatic Hydrocarbons (PAHs), nitrated PAHs (NPAHs) and oxygenated PAHs (OPAHs). In addition, the direct and indirect acting mutagenicity of the PM(2.5) and the potential for DNA damage to human lung cells were also measured. Significant reductions in BC (45%), OC (31%), MW< 300 PAH (26-73%), MW 302 PAH (22-77%), NPAH (15-68%), and OPAH (25-53%) concentrations were measured during the source control and Olympic periods. However, the mutagenicity of the PM(2.5) was significantly reduced only during the Olympic period. The PAH, NPAH, and OPAH composition of the PM(2.5) was similar throughout the study, suggesting similar sources during the different periods. During the source control period, the parent PAH concentrations were correlated with NO, CO, and SO(2) concentrations, indicating that these PAHs were associated with both local and regional emissions. However, the NPAH and OPAH concentrations were only correlated with the NO concentrations, indicating that the NPAH and OPAH were primarily associated with local emissions. The relatively high 2-nitrofluoranthene/1-nitropyrene ratio (25-46) and 2-nitrofluoranthene/2-nitropyrene ratio (3.4-4.8), suggested a predominance of photochemical formation of NPAHs through OH-radical-initiated reactions in the atmosphere. On average, the ?NPAH and ?OPAH concentrations were 8% of the parent PAH concentrations, while the direct-acting mutagenicity (due to the NPAH and OPAH) was 200% higher than the indirect-acting mutagenicity (due to the PAH). This suggests that NPAH and OPAH make up a significant portion of the overall mutagenicity of PM(2.5) in Beijing. PMID:21766847

Wang, Wentao; Jariyasopit, Narumol; Schrlau, Jill; Jia, Yuling; Tao, Shu; Yu, Tian-Wei; Dashwood, Roderick H; Zhang, Wei; Wang, Xuejun; Simonich, Staci L Massey

2011-07-18

114

Concentration and Photochemistry of PAHs, NPAHs, and OPAHs and Toxicity of PM2.5 during the Beijing Olympic Games  

PubMed Central

Atmospheric particulate matter with diameter <2.5 um (PM2.5) was collected at Peking University (PKU) in Beijing, China before, during, and after the 2008 Olympics and analyzed for black carbon (BC), organic carbon (OC), lower molecular weight (MW<300) and MW302 Polycyclic Aromatic Hydrocarbons (PAHs), nitrated PAHs (NPAHs) and oxygenated PAHs (OPAHs). In addition, the direct and indirect acting mutagenicity of the PM2.5 and the potential for DNA damage to human lung cells were also measured. Significant reductions in BC (45%), OC (31%), MW< 300 PAH (26% – 73%), MW 302 PAH (22% – 77%), NPAH (15% – 68%) and OPAH (25% – 53%) concentrations were measured during the source control and Olympic Olympic period. However, the mutagenicity of the PM2.5 was significantly reduced only during the Olympic period. The PAH, NPAH, and OPAH composition of the PM2.5 was similar throughout the study, suggesting similar sources during the different periods. During the source control period, the parent PAH concentrations were correlated with NO, CO, and SO2 concentrations, indicating that these PAHs were associated with both local and regional emissions. However, the NPAH and OPAH concentrations were only correlated with the NO concentrations, indicating that the NPAH and OPAH were primarily associated with local emissions. The relatively high 2-nitrofluoranthene/1-nitropyrene ratio (25 – 46) and 2-nitrofluoranthene/2-nitropyrene ratio (3.4 – 4.8), suggested a predominance of photochemical formation of NPAHs through OH-radical-initiated reactions in the atmosphere. On average, the ?NPAH and ?OPAH concentrations were 8% of the parent PAH concentrations, while the direct-acting mutagenicity (due to the NPAH and OPAH) was 200% higher than the indirect-acting mutagenicity (due to the PAH). This suggests that NPAH and OPAH make up a significant portion of the overall mutagenicity of PM2.5 in Beijing.

WANG, WENTAO; JARIYASOPIT, NARUMOL; SCHRLAU, JILL; JIA, YULING; TAO, SHU; YU, TIAN-WEI; DASHWOOD, RODERICK H.; ZHANG, WEI; WANG, XUEJUN; SIMONICH, STACI L. MASSEY

2011-01-01

115

Distribution of PAHs in surface soils from petroleum handling facilities in Calabar.  

PubMed

The level of concentrations of polycyclic aromatic hydrocarbons (PAHs) in surface soils from petroleum handling facilities (kerosene tank, generating plant, petrol stations, mechanic workshops, leaking pipeline and air port fuel dump) from Calabar metropolis southeastern Nigeria was determined by gas chromatography/ mass spectrometry. The results show that total polycyclic aromatic hydrocarbons (PAHs) varied from 1.80 to 334.43 mg/kg with a mean of 50.31 mg/kg. The lowest value of 1.80 mg/kg was obtained from petrol station while the highest value of 334.43 mg/kg was obtained from facility characterised by petrol stations and mechanic workshops. The ratio of phenanthrene/anthracene and fluoranthene/pyrene, varied from 0.43 to 27.72 and from 0.14 to 17.76 respectively. These ratios indicate various sources for the PAH. The two to three ring PAHs are the most abundant. Based on the PAH ratios and content alone it is not possible to distinguish between contribution from motor vehicle exhaust, gasoline spillage, used engine oil or petroleum production. However, considering the area of the study, it is very likely that the major source of soil contamination is originating from petroleum product. PMID:17106773

Nganje, T N; Edet, A E; Ekwere, S J

2006-11-15

116

The yeast lipin orthologue Pah1p is important for biogenesis of lipid droplets  

PubMed Central

Lipins are phosphatidate phosphatases that generate diacylglycerol (DAG). In this study, we report that yeast lipin, Pah1p, controls the formation of cytosolic lipid droplets. Disruption of PAH1 resulted in a 63% decrease in droplet number, although total neutral lipid levels did not change. This was accompanied by an accumulation of neutral lipids in the endoplasmic reticulum (ER). The droplet biogenesis defect was not a result of alterations in neutral lipid ratios. No droplets were visible in the absence of both PAH1 and steryl acyltransferases when grown in glucose medium, even though the strain produces as much triacylglycerol as wild type. The requirement of PAH1 for normal droplet formation can be bypassed by a knockout of DGK1. Nem1p, the activator of Pah1p, localizes to a single punctum per cell on the ER that is usually next to a droplet, suggesting that it is a site of droplet assembly. Overall, this study provides strong evidence that DAG generated by Pah1p is important for droplet biogenesis.

Adeyo, Oludotun; Horn, Patrick J.; Lee, SungKyung; Binns, Derk D.; Chandrahas, Anita; Chapman, Kent D.

2011-01-01

117

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

PubMed

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

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

2013-04-15

118

Use of solvents to enhance PAH biodegradation of coal tar-  

Microsoft Academic Search

Bioremediation of coal tar-contaminated soils containing polycyclic aromatic hydrocarbons (PAHs) is highly challenging because of the low solubility and strong sorption properties of PAHs. Five coal tar-contaminated soils from former manufactured gas plant (MGP) sites were pretreated with two solvents, acetone and ethanol to enhance the bioavailability of the PAH compounds. The biodegradation of various PAHs in the pretreated soils

Pak-Hing Lee; Say Kee Ong; Johanshir Golchin

2001-01-01

119

Extractability and Subsequent Biodegradation of PAHs from Contaminated Soil  

Microsoft Academic Search

The biodegradation of polyaromatic hydrocarbons (PAHs) has been well documented; however, the biodegradation of PAHs in contaminated soil has proved to be problematic. Sorption of PAHs to soil over time can significantly decrease their availability for extraction much less than for biodegradation. In this study the ability of various organic solvents to extract PAHs from coal tar-contaminated soil obtained from

John J. Kilbane; S. Mt

1998-01-01

120

Spitzer Spectroscopy of Infrared-luminous Galaxies: Diagnostics of Active Galactic Nuclei and Star Formation and Contribution to Total Infrared Luminosity  

NASA Astrophysics Data System (ADS)

We use mid-infrared (MIR) spectroscopy from the Spitzer Infrared Spectrograph to study the nature of star-formation and supermassive black hole accretion for a sample of 65 IR-luminous galaxies at 0.02 < z < 0.6 with F(24 ?m) > 1.2 mJy. The MIR spectra cover wavelengths 5-38 ?m, spanning the polycyclic aromatic hydrocarbon (PAH) features and important atomic diagnostic lines. Our sample of galaxies corresponds to a range of total IR luminosity, L IR = L(8-1000 ?m) = 1010-1012 L ? (median L IR of 3.0 × 1011 L ?). We divide our sample into a subsample of galaxies with Spitzer Infrared Array Camera 3.6-8.0 ?m colors indicative of warm dust heated by an active galactic nucleus (AGN; IRAGN) and those galaxies whose colors indicate star-formation processes (non-IRAGN). Compared to the non-IRAGN, the IRAGN show smaller PAH emission equivalent widths, which we attribute to an increase in mid-IR continuum from the AGN. We find that in both the IRAGN and star-forming samples, the luminosity in the PAH features correlates strongly with [Ne II] ?12.8 ?m emission line, from which we conclude that the PAH luminosity directly traces the instantaneous star-formation rate (SFR) in both the IRAGN and star-forming galaxies. We compare the ratio of PAH luminosity to the total IR luminosity, and we show that for most IRAGN star-formation accounts for 10%-50% of the total IR luminosity. We also find no measurable difference between the PAH luminosity ratios of L 11.3/L 7.7 and L 6.2/L 7.7 for the IRAGN and non-IRAGN, suggesting that AGN do not significantly excite or destroy PAH molecules on galaxy-wide scales. Interestingly, a small subset of galaxies (8 of 65 galaxies) show a strong excess of [O IV] ?25.9 ?m emission compared to their PAH emission, which indicates the presence of heavily-obscured AGN, including 3 galaxies that are not otherwise selected as IRAGN. The low PAH emission and low [Ne II] emission of the IRAGN and [O IV]-excess objects imply the IR luminosity of these objects is dominated by processes associated with the AGN. Because these galaxies lie in the "green valley" of the optical color-magnitude relation and have low implied SFRs, we argue their hosts have declining SFRs and these objects will transition to the red sequence unless some process restarts their star-formation.

Shipley, Heath V.; Papovich, Casey; Rieke, George H.; Dey, Arjun; Jannuzi, Buell T.; Moustakas, John; Weiner, Benjamin

2013-05-01

121

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

NASA Astrophysics Data System (ADS)

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

Herklotz, Ilka; Gocht, Tilman; Grathwohl, Peter

2010-05-01

122

PAH-DNA Adducts, Cigarette Smoking, GST Polymorphisms, and Breast Cancer Risk  

PubMed Central

Background Polycyclic aromatic hydrocarbons (PAHs) may increase breast cancer risk, and the association may be modified by inherited differences in deactivation of PAH intermediates by glutathione S-transferases (GSTs). Few breast cancer studies have investigated the joint effects of multiple GSTs and a PAH biomarker. Objective We estimated the breast cancer risk associated with multiple polymorphisms in the GST gene (GSTA1, GSTM1, GSTP1, and GSTT1) and the interaction with PAH–DNA adducts and cigarette smoking. Methods We conducted unconditional logistic regression using data from a population-based sample of women (cases/controls, respectively): GST polymorphisms were genotyped using polymerase chain reaction and matrix-assisted laser desorption/ionization time-of-flight assays (n = 926 of 916), PAH–DNA adduct blood levels were measured by competitive enzyme-linked immunosorbent assay (n = 873 of 941), and smoking status was assessed by in-person questionnaires (n = 943 of 973). Results Odds ratios for joint effects on breast cancer risk among women with at least three variant alleles were 1.56 [95% confidence interval (CI), 1.13–2.16] for detectable PAH–DNA adducts and 0.93 (95% CI, 0.56–1.56) for no detectable adducts; corresponding odds ratios for three or more variants were 1.18 (95% CI, 0.82–1.69) for ever smokers and 1.44 (95% CI, 0.97–2.14) for never smokers. Neither interaction was statistically significant (p = 0.43 and 0.62, respectively). Conclusion We found little statistical evidence that PAHs interacted with GSTT1, GSTM1, GSTP1, and GSTA1 polymorphisms to further increase breast cancer risk.

McCarty, Kathleen M.; Santella, Regina M.; Steck, Susan E.; Cleveland, Rebecca J.; Ahn, Jiyoung; Ambrosone, Christine B.; North, Kari; Sagiv, Sharon K.; Eng, Sybil M.; Teitelbaum, Susan L.; Neugut, Alfred I.; Gammon, Marilie D.

2009-01-01

123

Isolation of adherent polycyclic aromatic hydrocarbon (PAH)-degrading bacteria using PAH-sorbing carriers  

SciTech Connect

Two different procedures were compared to isolate polycyclic aromatic hydrocarbon (PAH)-utilizing bacteria from PAH-contaminated soil and sludge samples, i.e., (i) shaken enrichment cultures in liquid mineral medium in which PAHs were supplied as crystals and (ii) a new method in which PAH degraders were enriched on and recovered from hydrophobic membranes containing sorbed PAHs. Both techniques were successful, but selected from the same source different bacterial strains able to grow on PAHs as the sole source of carbon and energy. The liquid enrichment mainly selected for Sphingomonas spp., whereas the membrane method exclusively led to the selection of Mycobacterium spp. Furthermore, in separate membrane enrichment set-ups with different membrane types, three repetitive extragenic palindromic PCR-related Mycobacterium strains were recovered. The new Mycobactereium isolates were strongly hydrophobic and displayed the capacity to adhere strongly to different surfaces. One strain, Mycobacterium sp. LB501T, displayed an unusual combination of high adhesion efficiency and an extremely high negative charge. This strain may represent a new bacterial species as suggested by 16S rRNA gene sequence analysis. These results indicate that the provision of hydrophobic sorbents containing sorbed PAHs in the enrichment procedure discriminated in favor of certain bacterial characteristics. The new isolation method is appropriate to select for adherent PAH-degrading bacteria, which might be useful to biodegrade sorbed PAHs in soils and sludge.

Bastiaens, L.; Springael, D.; Wattiau, P.; Harms, H.; DeWachter, R.; Verachtert, H.; Diels, L.

2000-05-01

124

Photochemistry of PAHs on Arctic Snow Grains  

NASA Astrophysics Data System (ADS)

Photochemical reactions can greatly influence the chemistry of surface snow and transform many of the organic pollutants in snowpacks. Little is known about the rates and mechanisms of these photochemical processes, but they likely play a large role in determining lifetimes of many pollutants in snow. Our goal here is to understand the fate of one class of organic pollutants, polycyclic aromatic hydrocarbons (PAH's), in snow and ice. PAH's are ubiquitous in the environment and have well-studied toxicities. We have focused on the degradation kinetics of phenanthrene, pyrene, and fluoranthene on ice, as these are the most abundant PAH's found in Arctic snow. Laboratory photochemistry experiments were conducted using frozen solutions of PAH's illuminated with simulated solar light. Direct photolysis rates were measured using frozen solutions of the PAH's in Milli-Q with added solutes, whereas indirect photo-oxidation reactions with hydroxyl radical were measured in similar frozen solutions with added hydrogen peroxide as a source of ·OH. Using data from our group's previous and ongoing research on the levels of hydroxyl radical in Summit snow, we have been able to begin to assess the relative significance of indirect photo-oxidation and direct photolysis of PAH's as mechanisms of degradation for these compounds on snow and ice. Summit field data indicate that direct photolysis is the main mechanism of phenanthrene degradation, and laboratory experiments confirm this finding for all three PAH compounds. Data extrapolated to Summit conditions suggests that indirect photo-oxidation via ·OH accounts for only a small fraction (about 2 to 4%) of PAH degradation on ice. Our direct photolysis data suggest that PAH lifetimes on snow and ice under Arctic conditions are on the order of 1 to 7 hours during mid-summer. These results are based on photolysis experiments conducted on ice pellets made from PAH solutions. Actual snowpack lifetimes are likely to be longer, given that PAH's are most likely to be associated with particulate matter (e.g, deposited atmospheric aerosols) in the snow.

Ram, K.; Anastasio, C.

2007-12-01

125

Mycoremediation of PAH-contaminated soil  

Microsoft Academic Search

Out of a number of white-rot fungal cultures, strains ofIrpex lacteus andPleurotus ostreatus were selected for degradation of 7 three- and four-ring unsubstituted aromatic hydrocarbons (PAH) in two contaminated industrial\\u000a soils. Respective data for removal of PAH in the two industrial soils byI. lacteus were: fluorene (41 and 67%), phenanthrene (20 and 56%), anthracene (29 and 49%), fluoranthene (29 and

M. BIIATT; T. Cajthaml; V. Šašek

2002-01-01

126

Developing strategies for PAH and TCE bioremediation  

SciTech Connect

Bioremediation is the controlled use of microbes, commonly bacteria and fungi, to reclaim soil and water contaminated with substances that are deleterious to human health and the environment. The organisms used often naturally inhabit the polluted matrix; however, they may inhabit a different environment and be used as seed organisms because of their ability to degrade a specific class of substances. It is because of the wide diversity of microbial metabolic potential that bioremediation is possible. Polyaromatic hydrocarbons (PAHs) are organic compounds that are ubiquitous in the environment. They are present in fossil fuels and are formed during the incomplete combustion of organic material. PAHs exhibit low volatility and low aqueous solubility. As the molecular weight of these compounds increases, there is an exponential decrease in solubility and volatility. PAHs tend to adsorb onto soils and sediments because of their hydrophobic character, which is an intrinsic function of molecular size. The microbial degradation of individual PAHs by pure cultures and mixed populations occurs under a wide range of soil types and environmental conditions. Generally, the factors having the greatest influence on PAH biodegradation rates are soil moisture content, pH, inorganic nutrients present, PAH loading rates, initial PAH concentrations, and the presence of an acclimated microbial population. Feasibility studies are essential for developing a bioremediation strategy and are performed in a phased testing program that is designed to accomplish a number of objectives. These objectives include establishing an indigenous microbial population that will degrade specific contaminants, defining the rate-limiting factors for enhanced PAH degradation and the optimal treatment in terms of rates and cleanup levels attainable, and developing design parameters for field operations.

Mahaffey, W.R.; Nelson, M.; Kinsella, J. (Ecova Corp., Redmond, WA (United States)); Compeau, G. (Applied Geosciences, Inc., Bellevue, WA (United States))

1991-10-01

127

PAHFIT: Properties of PAH Emission  

NASA Astrophysics Data System (ADS)

PAHFIT is an IDL tool for decomposing Spitzer IRS spectra of PAH emission sources, with a special emphasis on the careful recovery of ambiguous silicate absorption, and weak, blended dust emission features. PAHFIT is primarily designed for use with full 5-35 micron Spitzer low-resolution IRS spectra. PAHFIT is a flexible tool for fitting spectra, and you can add or disable features, compute combined flux bands, change fitting limits, etc., without changing the code. PAHFIT uses a simple, physically-motivated model, consisting of starlight, thermal dust continuum in a small number of fixed temperature bins, resolved dust features and feature blends, prominent emission lines (which themselves can be blended with dust features), as well as simple fully-mixed or screen dust extinction, dominated by the silicate absorption bands at 9.7 and 18 microns. Most model components are held fixed or are tightly constrained. PAHFIT uses Drude profiles to recover the full strength of dust emission features and blends, including the significant power in the wings of the broad emission profiles. This means the resulting feature strengths are larger (by factors of 2-4) than are recovered by methods which estimate the underlying continuum using line segments or spline curves fit through fiducial wavelength anchors.

Smith, J. D.; Draine, Bruce

2012-10-01

128

Mycoremediation of PAH-contaminated soil.  

PubMed

Out of a number of white-rot fungal cultures, strains of Irpex lacteus and Pleurotus ostreatus were selected for degradation of 7 three- and four-ring unsubstituted aromatic hydrocarbons (PAH) in two contaminated industrial soils. Respective data for removal of PAH in the two industrial soils by I. lacteus were: fluorene (41 and 67%), phenanthrene (20 and 56%), anthracene (29 and 49%), fluoranthene (29 and 57%), pyrene (24 and 42%), chrysene (16 and 32%) and benzo[a]anthracene (13 and 20%). In the same two industrial soils P. ostreatus degraded the PAH with respective removal figures of fluorene (26 and 35%), phenanthrene (0 and 20%), anthracene (19 and 53%), fluoranthene (29 and 31%), pyrene (22 and 42%), chrysene (0 and 42%) and benzo[a]anthracene (0 and 13%). The degradation of PAH was determined against concentration of PAH in non-treated contaminated soils after 14 weeks of incubation. The fungal degradation of PAH in soil was studied simultaneously with ecotoxicity evaluation of fungal treated and non-treated contaminated soils. Compared to non-treated contaminated soil, fungus-treated soil samples indicated decrease in inhibition of bioluminescence in luminescent bacteria (Vibrio fischerii) and increase in germinated mustard (Brassica alba) seeds. PMID:12094734

Bhatt, M; Cajthaml, T; Sasek, V

2002-01-01

129

Gene Expression Changes of Phases I and II Metabolizing Enzymes Induced by PAH Derivatives  

Microsoft Academic Search

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants, and generate various types of PAH derivatives, such as nitrated PAHs, hydroxylated PAHs, and PAH quinones through chemical reactions in the atmosphere. PAHs are well known to activate the aryl hydrocarbon receptor (AhR), followed by the induction of metabolizing enzymes mainly in the liver, while biological responses to PAH derivatives are not

KANAE BEKKI; HIDETAKA TAKIGAMI; GO SUZUKI; AKIRA TORIBA; NING TANG; TAKAYUKI KAMEDA; KAZUICHI HAYAKAWA

2012-01-01

130

Solubilization, solution equilibria, and biodegradation of PAH’s under thermophilic conditions  

Microsoft Academic Search

Biodegradation rates of PAHs are typically low at mesophilic conditions and it is believed that the kinetics of degradation is controlled by PAH solubility and mass transfer rates. Solubility tests were performed on phenanthrene, fluorene and fluoranthene at 20°C, 40°C and 60°C and, as expected, a significant increase in the equilibrium solubility concentration and of the rate of dissolution of

Sridhar Viamajala; Brent M. Peyton; Lee A. Richards; James N. Petersen

2007-01-01

131

Computational Study of the Thermodynamics of Atmospheric Nitration of PAHs via OH-Radical-Initiated Reaction  

NASA Astrophysics Data System (ADS)

Nitrated polycyclic aromatic hydrocarbons (NPAHs) are an important class of PAH derivatives that are more toxic than their parent PAHs (1) and are emitted from direct emission and secondary emission to the atmosphere. The secondary emissions, particularly the OH-radical initiated and NO3-radical-initiated reactions, have been shown to influence the NPAH concentrations in the atmosphere. Gas-phase reactions are thought to be the major sources of NPAHs containing four or fewer rings (2). Besides NPAHs, PAHs lead to a number of other products including oxygenated, hydroxy substituted and ring-opened PAH derivatives (3). For some PAHs, the OH-initiated and NO3-initiated reactions result in the formation of different NPAH isomers, allowing the ratio of these isomers to be used in the determination of direct or secondary emission sources. Previous studies have shown that the PAH gas-phase reactions with OH radical is initiated by the addition of OH radical to the aromatic ring to form hydroxycyclohexadienyl radicals (4). In the presence of NO2, these reactive intermediates readily nitrate with the elimination of water (4). The hydroxycyclohexadienyl-type radical intermediates are also prone to react with other species in the atmosphere or revert back to the original compound (3). The objective of this study was to investigate the thermodynamics of PAH nitration through day-time OH-radical-initiated reactions. The theoretical investigation were carried out using Density Functioanl Theory (B3LYP) and the 6-31G(d) basis set, as implemented in Gaussian03. A number of different PAHs were studied including fluoranthene, pyrene, as well as the molecular weight 302 PAHs such as dibenzo[a,l]pyrene. Computations were also used to predict unknown NPAHs formed by OH-radical-initiated reaction. All intermediates for the OH-radical addition and the following nitration were computed. We have discovered that the thermodynamic stability of the intermediates involved in the PAH oxygenation and nitration pathways are critical in explaining the atmospheric abundances of NPAHs. Specifically, we have found that the experimentally most abundant species had the most stable intermediates. Interestingly, the overall free energy of reaction was not a factor in determining the relative abundances of NPAHs.

Jariyasopit, N.; Cheong, P.; Simonich, S. L.

2011-12-01

132

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

PubMed

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-polluted/below threshold effects. These results indicate that local sources of PAHs, especially estuary discharges, lead to very different qualities of sediments in coastal zones, where traffic and industrial activities take place. PMID:12117050

Viguri, J; Verde, J; Irabien, A

2002-07-01

133

Polycyclic aromatic hydrocarbons (PAHs), nitrated PAHs and oxygenated PAHs in ambient air of the Marseilles area (South of France): Concentrations and sources  

Microsoft Academic Search

Ambient measurements (gas+particle phases) of 15 polycyclic aromatic hydrocarbons (PAHs), 17 nitrated PAHs (NPAHs) and 9 oxygenated PAHs (OPAHs) were carried out during July 2004 on three different sites (urban, sub-urban and rural) in the region of Marseilles (South of France). Atmospheric concentrations of these classes of polyaromatics are great of interest because of their high potential mutagenicity and carcinogenicity.

Alexandre Albinet; Eva Leoz-Garziandia; Hélène Budzinski; Eric ViIlenave

2007-01-01

134

Sources and distribution of polycyclic aromatic hydrocarbons (PAHs) in sediments from the Mar Piccolo of Taranto, Ionian Sea, southern Italy.  

PubMed

The concentrations of 17 parent PAHs, with molecular weight from 128 to 278 Daltons, were determined in surface sediments from the Mar Piccolo of Taranto. The analytical results were compared with the published results for other coastal areas of the Mediterranean Sea. The analyses were performed by gas chromatography coupled to mass spectrometry (GC-MS). Total PAH content in sediments ranged from 380 to 12750 ng g(-1) dry weight. The levels of the PAHs was higher than the one reported for sediments of the Adriatic Sea and Cretan Sea and of the same order of magnitude of the one known for coastal areas of the western and the eastern Mediterranean Sea. The PAHs distribution showed similar patterns in all sediments analyzed, with compounds with three or more rings. These patterns of distribution and the ratios among low molecular weight PAHs/high molecular weight PAHs, phenanthrene/anthracene and fluoranthene/pyrene indicated that pyrogenic inputs are the main source of these compounds in the Mar Piccolo basin. Based on the comparison of both the individual and the total PAH concentrations with proposed sediment quality guidelines, the acute biological effects on the marine organisms should be negligible. PMID:12817639

Lerario, Vito Luigi; Giandomenico, Santina; Lopez, Luigi; Cardellicchio, Nicola

2003-04-01

135

Nitro-PAH compounds in the atmosphere of Sao Paulo, Brazil  

NASA Astrophysics Data System (ADS)

Nitrated polycyclic aromatic hydrocarbons (nitro-PAH) are the chemical class with potent mutagenic compounds. These species are emitted from a wide range of combustion sources. Some compounds can be formed photo chemically via reactions of their parents PAH with OH or NO_3 radicals (in the presence of NO_2) in the gas phase as well as N_2O_5 or HNO_3 when parent PAH is associated with aerosols. In the tropics, an important source of particulate PAH and nitro-PAH is biomass burning used for clearings in forest and for making easier the harvesting of sugar cane. Brazil owns 25% of global sugar cane and is the major producer in the world. This burning produces soot, which remains for along time in the air and can cause respiratory diseases. This study was conducted in 3 cities in São Paulo State during sugar cane burning episodes. Back trajectories were calculated by University of São Paulo Trajectory Model for determination of air parcel trajectories over the sites. Atmospheric samples were collected on quartz fiber filters for 24 hours in high-volume sampler during one week. A Soxhlet apparatus filled with methylene chloride was used for extracting the filters. This residue was submitted to HPLC separation and the 3 obtained fractions (n-alkanes, PAH and nitro-PAH) were analyzed by both gas chromatography/flame ionization and gas chromatography/mass spectrometry detection. The isomers 2-, 3-, 8-nitrofluoranthene and 2-nitropyrene were identified and results show large differences between the sites. 2-nitropyrene/2-nitrofluoranthene ratios were calculated indicating the daytime reactions promoted by OH radicals.

Mabilia, R.; Cecinato, A.; Tomasi Scianò, M. C.; Vasconcellos, P.; Carvalho, L.; Mathos, L.; Franco, L.

2003-04-01

136

From the Laboratory to Space: Neutral and Ionized PAHs in Translucent Interstellar Clouds  

NASA Astrophysics Data System (ADS)

We describe and discuss the laboratory experiments that were designed to test the proposal of relating the origin of some of the diffuse interstellar bands (DIBs) to neutral and ionized polycyclic aromatic hydrocarbons (PAHs) present in diffuse interstellar clouds. The spectra of several cold, isolated gas-phase PAH ions and neutral molecules have been measured using the COSmIC laboratory facility at NASA-Ames and are compared with an extensive set of astronomical spectra of reddened, early type stars. The COSmIC facility combines a supersonic free jet expansion with discharge plasma and high-sensitivity cavity ringdown spectroscopy to provide experimental conditions that closely mimic the interstellar conditions. This comparison provides - for the first time - accurate upper limits for the abundances of specific PAH molecules and ions along specific lines-of-sight. Something that is not attainable from infrared observations alone. The comparison of these unique laboratory data with high resolution, high S/N ratio astronomical observations leads to major findings regarding the column densities of the individual PAH molecules and ions that are probed in this survey and leads to clear and unambiguous conclusions regarding the expected abundances for PAHs of various sizes and charge states in these environments. This quantitative survey of neutral and ionized PAHs in the optical range opens the way for unambiguous quantitative searches of PAHs and complex organics in a variety of interstellar and circumstellar environments. Acknowledgements: F.S. acknowledges the support of the NASA’s Space Mission Directorate APRA Program. The authors are deeply grateful to the ESO archive as well as to the ESO staff members for their active support.

Salama, Farid; Galazutdinov, G.; Biennier, L.; Krelowski, J.

2012-05-01

137

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

PubMed Central

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

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

2011-01-01

138

HELIOS: A helium line-ratio spectral-monitoring diagnostic used to generate high resolution profiles near the ion cyclotron resonant heating antenna on TEXTOR  

NASA Astrophysics Data System (ADS)

Radial profiles of electron temperature and density are measured at high spatial (~1 mm) and temporal (>=10 ?s) resolution using a thermal supersonic helium jet. A highly accurate detection system is applied to well-developed collisional-radiative model codes to produce the profiles. Agreement between this measurement and an edge Thomson scattering measurement is found to be within the error bars (<~20%). The diagnostic is being used to give profiles near the ion cyclotron resonant heating antenna on TEXTOR to better understand RF coupling to the core.

Unterberg, E. A.; Schmitz, O.; Fehling, D. H.; Stoschus, H.; Klepper, C. C.; Muñoz-Burgos, J. M.; Van Wassenhove, G.; Hillis, D. L.

2012-10-01

139

HELIOS: a helium line-ratio spectral-monitoring diagnostic used to generate high resolution profiles near the ion cyclotron resonant heating antenna on TEXTOR.  

PubMed

Radial profiles of electron temperature and density are measured at high spatial (?1 mm) and temporal (?10 ?s) resolution using a thermal supersonic helium jet. A highly accurate detection system is applied to well-developed collisional-radiative model codes to produce the profiles. Agreement between this measurement and an edge Thomson scattering measurement is found to be within the error bars (?20%). The diagnostic is being used to give profiles near the ion cyclotron resonant heating antenna on TEXTOR to better understand RF coupling to the core. PMID:23126896

Unterberg, E A; Schmitz, O; Fehling, D H; Stoschus, H; Klepper, C C; Muñoz-Burgos, J M; Van Wassenhove, G; Hillis, D L

2012-10-01

140

Correlations between the spatial configuration and behavior of large PAHS  

SciTech Connect

Several 7-12 ring polycyclic aromatic hydrocarbons (PAHs) were synthesized. All were ''peropyrenes'', made by condensation of perinaphthone-type ketones. Product mixture analyses by liquid chromatography (LC) with diode-array detection identified approximately 15 previously unreported PAHs. LC retention correlated with PAH three-dimensional shape. PAHs with intramolecular strain eluted earlier than less strained isomers, resulting in overlap of PAHs with different ring numbers. Pyrene eluted after hexabenzo (a, cd, f, j, lm, o) perylene, although the latter PAH had seven more rings. The degree of planarity within isomer sets can be estimated by UV absorbance bandshapes. Less planar isomers had increasingly shallow minima between the maxima.

Fetzer, J.C.

1986-09-01

141

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

Microsoft Academic Search

An increased urinary albumin excretion (albuminuria) is an established test for the early detection of renal disease and is also recognized as a risk factor for cardiovascular disease and mortality in a number of clinical settings. There is an established body of data which shows that a random urinary albumin:creatinine ratio (ACR) based on a random urine sample correlates well

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

2009-01-01

142

Formation Conditions of Icy Materials in Comet C/2004 Q2 (Machholz). II. Diagnostics Using Nuclear Spin Temperatures and Deuterium-to-Hydrogen Ratios in Cometary Molecules  

NASA Astrophysics Data System (ADS)

We report the nuclear spin temperatures (T spin) of H2O and CH4 in comet C/2004 Q2 (Machholz) based on high-dispersion spectroscopic observations of the comet in the L band taken by the Keck II telescope with the NIRSPEC spectrograph on 2005 January 30.2 UT. The ortho-to-para abundance ratio of H2O was determined to be 3.13+0.56 -0.42, which is consistent with the high-temperature limit of H2O (3.0). The lower limit of T spin is 27 K (95% confidence limit (c.l.)) for H2O. In the case of CH4, the abundance ratios of A:E:F are consistent with 5:2:9 (high-temperature limit) and the lower limit of T spin is 36 K (95%-c.l.). We also report the result of our sensitive search for mono-deuterated methane (CH3D) in C/2004 Q2 (Machholz). A candidate for the emission line from the CH3D ?4 RR(3, 3) transition was found in our spectra. Although the D/H ratio in methane could be determined as (3.8 ± 1.3) × 10-3 based on a tentative detection of CH3D, this emission line also might be assigned to other molecules, e.g., CH3OH. Therefore, we conclude that the D/H ratio in methane is lower than 6.4 × 10-3 (95%-c.l.) in the comet. Both the lower limits of T spin of H2O and CH4 and the upper limit of the D/H ratio in methane indicate the formation of molecules frozen in C/2004 Q2 (Machholz) at relatively higher temperatures compared with the typical Oort Cloud comets.

Kawakita, Hideyo; Kobayashi, Hitomi

2009-03-01

143

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

NASA Astrophysics Data System (ADS)

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

Mannino, Maria Rosaria; Orecchio, Santino

144

Contamination levels and spatial distributions of heavy metals and PAHs in surface sediment of Imam Khomeini Port, Persian Gulf, Iran.  

PubMed

Imam Khomeini Port (IKP) is the largest Iranian commercial port. Because of many petrochemical industries and urban areas are located around this port and also having heavy ship traffic, concentrations of PAHs, mercury and other heavy metals were measured as the first time in surface sediment of the jetties. The highest concentrations of PAHs, Hg, Cu, Pb and Fe were recorded at Site 1, located in the vicinity of the petrochemical industrial zone, where ships are repaired. The highest concentration of Zn was found at Site 4, which is the jetty for loading mineral materials. The comparison between measured values in this study and some sediment quality guidelines indicated that the concentrations of mercury and PAHs are much higher than other studies. Also, the ratios of PAHs in the stations showed a mixture of both of pyrolytic and petrogenic sources with a dominance of pyrolytic sources. PMID:23523119

Abdollahi, Sajad; Raoufi, Zeinab; Faghiri, Iraj; Savari, Ahmad; Nikpour, Yadolah; Mansouri, Ali

2013-03-21

145

The Emissions of PAHs and Heavy Metals from Co-Combustion of Petrochemical Sludge with Coal in CFB Incinerator  

NASA Astrophysics Data System (ADS)

The polycyclic aromatic hydrocarbons (PAHs) and heavy metals (Hg, Pb, Ni, Cr, Cu, Zn) emission characteristics in flue gas from co-combustion of petrochemical sludge and coal were investigated in a pilot-scale circulating fluidized bed (CFB) incinerator with a thermal input of 0.2 MW. Experimental results show that when mass ratio of petrochemical sludge/coal increases from 10% to 40%, PAHs, Hg and Zn emissions increase, while Pb and Ni emissions decrease. Mass mixing ratio has no obvious effect on the emissions of Cr and Cu. As combustion temperature increases, PAHs emission decreases at first and then increases, there is an optimum combustion temperature inhibiting PAHs formation, while emissions of Hg, Pb, Cu, Zn increase relatively rapidly. With Ca/S molar ratio increasing, PAHs, Hg, Pb, Ni, and Cu emissions decrease due to adsorption by calcium sorbents. Limestone is effective in adsorbing Pb and Ni, while lime is suitable to adsorb Hg and Cu. However, Ca/S molar ratio doesn't have much influence on the emissions of Cr and Zn. Some combustion parameters are recommended based on stable combustion and low pollutant emission.

Zhu, Ge; Zhao, Changsui; Chen, Huichao; Chen, Xiaoping; Liang, Cai

146

[Influence of operating parameters on surfactant-enhanced washing to remedy PAHs contaminated soil].  

PubMed

Liquid/solid ratio (L/S) is an important influencing factor on contaminant removal in soil washing. The impact of different liquid/solid ratio on washing performance with Triton X-100 and Tween-80 was studied respectively and evaluated through removal ratio (R), surfactant adsorption loss ratio (V(s)) and solubilization percent (SP). The results presented that the performance of washing to remove PAHs in soil was significantly affected by liquid/solid ratio. PAH removal ratio was gradually increased with liquid/solid ratio increasing in the non-linear form, R presented nonlinear increasing until L/S = 10: 1. Surfactant adsorption loss ratio was insignificantly decreased. At the same liquid/solid ratio, removal ratio of Triton X-100 is more than that of Tween-80. V(s) presented drastic decreasing until L/S = 10: 1, adsorption loss ratio of Triton X-100 is less than that of Tween-80. SP was decreased after maximum value is occurred at L/S = 10: 1. Combining with R, V(s) and SP, L/S = 10:1 should be an effective washing point, Triton X-100 should be a reasonable washing solution and SP is a more effective index to chose liquid/solid ratio. When Triton X-100 is as washing solution and L/S = 10: 1, R, V(s) and SP is 74.7%, 23.47% and 48.99%, respectively. PMID:22624395

Wu, Wei; Jiang, Lin; Chen, Jia-Jun; Peng, Sheng

2012-03-01

147

32P-Postlabeling in Studies of PAH Activation.  

National Technical Information Service (NTIS)

Polycyclic aromatic hydrocarbons (PAH) undergo metabolic activation reactions to form intermediates that react with DNA to form covalent adducts. PAH administration leads to the formation of various types of DNA adducts that may differ between species, st...

J. A. Ross S. Nesnow

1992-01-01

148

Effect of the gasoline additives on PAH emission.  

PubMed

PAH emission from the powered engines fueled by a 95 leadfree gasoline (95-LFG), a 92 leadfree gasoline (92-LFG) and a Premium leaded gasoline (PLG) with two gasoline additives (SA and SB) were collected using a PAH sampling system with a particulate interception device. Twenty one PAHs were analyzed primarily by an GC/MS, while eight metal elements were determined mainly by an ICP-AES. This investigation showed that the gasoline additives contain more amounts of carcinogenic PAHs than gasolines do. Blending these additives do raise the PAH content in the gasolines, simultaneously, will emit more amount of PAHs from the tailpipe of engine exhaust. It is suggested that before a gasoline additive is commercialized, an assessment on its PAH emission should be evaluated to make sure that the additive will not emit more PAHs and cause adverse effect on public health. PMID:9532730

Mi, H H; Lee, W J; Chen, S J; Lin, T C; Wu, T L; Hu, J C

1998-04-01

149

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

PubMed Central

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

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

2012-01-01

150

PAH characteristics in the ambient air of traffic-source  

Microsoft Academic Search

Twenty-seven PAH (polycyclic aromatic hydrocarbon) samples in the ambient air of a traffic-source were investigated for their concentration, particle-bound PAH composition, phase distribution, time variation, and distance variation. In addition, 18 and 12 PAH samples in the ambient air of an urban site and a rural site, respectively, were determined and compared with those of the traffic-source. The total-PAH concentrations

Wen-Jhy Lee; Ya-Fen Wang; Ta-Chang Lin; Ying-Yuan Chen; Weng-Chang Lin; Chin-Chuen Ku; Juei-Tang Cheng

1995-01-01

151

Biodegradation of PAH Mixtures by a Marine Sediment Enrichment  

Microsoft Academic Search

Aerobic polycyclic aromatic hydrocarbon (PAH) degrading bacteria were enriched from creosote contaminated marine sediments (Puget Sound, Washington, USA) using a continuous-flow fluidized-bed reactor. Artificial seawater media and a mixture of seven 2 to 3-ring PAHs were used as enrichment substrates. The biodegradability of PAH mixtures by the enrichment was determined in batch vial assays. The tested PAH mixtures included alkyl

Minna K. Männistö; Esa S. Melin; Jaakko A. Puhakka; John F. Ferguson

1996-01-01

152

Sources, transport and fate of PAHs in sediments and superficial water of a chronically polluted semi-enclosed body of seawater: linking of compartments.  

PubMed

This paper describes a study of the occurrence, levels and temporal evolution of PAHs in a bay characterized by persistent chronic impacts. A total of 40 samples, 20 of sediment and 20 of water, were taken at each of five different stations, in four sampling campaigns. Analyses of pollutants have been made using GC-MS. Results indicate that in a coastal environment subjected to chronic pollution by pyrolytic PAHs, episodes of petrogenic pollution, like oil-spills, can be identified by the combination of different source ratios. Results also indicate that, in the study area, PAHs are transported from superficial water to sediment. This conclusion is based on the degree of coincidence found in the presence/absence of individual PAHs in both compartments and in their petrogenic/pyrolytic nature, the positive sedimentation rate in the study area, together with the performance of the analyses of unfiltered water and the distribution of sources of PAHs found. PMID:23525235

Rojo-Nieto, Elisa; Sales, Diego; Perales, José Antonio

2013-05-01

153

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

Microsoft Academic Search

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

A. K. Haritash; C. P. Kaushik

2009-01-01

154

CHARACTERISTICS OF PAHS INTRINSIC DEGRADATION IN TWO COKE FACTORY SOILS  

Microsoft Academic Search

Polycyclic aromatic hydrocarbons (PAHs) are the most commonly found pollutants in former coke site grounds. These organic pollutants are particularly a concern because of their possible toxic, carcinogenic or mutagenic properties. Biodegradation is one possible pathway for PAHs elimination from soils. This study aims to evaluate intrinsic degradation potential of PAHs in soils taken from two former coke sites, differing

Christine Lors; Jean-Remi Mossmann

2005-01-01

155

STUDIES ON THE MICROBIAL ECOLOGY OF PAH DEGRADATION  

EPA Science Inventory

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

156

Comparison of sedimentary PAHs in the rivers of Ammer (Germany) and Liangtan (China): differences between early- and newly-industrialized countries.  

PubMed

As a proxy to trace the impact of anthropogenic activity, sedimentary polycyclic aromatic hydrocarbons (PAHs) are compared between the early industrialized and newly industrialized countries of Germany and China, respectively. Surface sediment samples in the Ammer River of Germany and the Liangtan River of China were collected to compare concentration levels, distribution patterns, and diagnostic plots of sedimentary PAHs. Total concentrations of 16 PAHs in Ammer sediments were significantly higher by a factor of ~4.5 than those in Liangtan. This contrast agrees with an extensive literature survey of PAH levels found in Chinese versus European sediments. Distribution patterns of PAHs were similar across sites in the Ammer River, whereas they were highly varied in the Liangtan River. Pyrogenic sources dominated in both cases. Strong correlations of the sum of 16 PAHs and PAH groups with TOC contents in the Liangtan River may indicate coemission of PAHs and TOC. Poor correlations of PAHs with TOC in the Ammer River indicate that other factors exert stronger influences. Sedimentary PAHs in the Ammer River are primarily attributed to input of diffuse sources or legacy pollution, while sediments in the Liangtan River are probably affected by ongoing point source emissions. Providing further evidence of a more prolonged anthropogenic influence are the elevated black carbon fractions in sedimentary TOC in the Ammer compared to the Liangtan. This implies that the Liangtan River, like others in newly industrialized regions, still has a chance to avoid legacy pollution of sediment which is widespread in the Ammer River and other European waterways. PMID:23252503

Liu, Ying; Beckingham, Barbara; Ruegner, Hermann; Li, Zhe; Ma, Limin; Schwientek, Marc; Xie, Huan; Zhao, Jianfu; Grathwohl, Peter

2013-01-07

157

Sorption and chemical transformation of PAH`s on coal fly ash  

SciTech Connect

The major objective of this work was to characterize the interactions of coal fly ash with polycyclic aromatic hydrocarbons (PAHS) and their derivatives, and to attempt to understand the influence of the surface properties of coal ash (and other atmospheric particles) on the chemical transformations of polycyclic aromatic compounds. Our studies have concentrated on the photochemical behavior of PAHs sorbed form the vapor phase on coal fly ashes, and compositional subfractions obtained therefrom. The PAHs are deposited onto the fly ash substrates from the vapor phase, using apparatus and techniques developed in this laboratory in order to simulate, as closely as possible under laboratory conditions, the processes by which PAHs deposit onto fly ash particles in the atmosphere. In this report phototransformation of pyrene sorbed on fly ash fractions, and phototransformations of 1-nitropyrene sorbed on fly ash fractions are discussed.

Mamantov, G.; Wehry, E.L.

1995-05-09

158

PAHS: a Nepali project with international implications  

Microsoft Academic Search

Purpose – The purpose of this paper is to describe the Patan Academy of Health Sciences (PAHS), an initiative for rural medical education in Nepal, and show its implications for rural medical education in other contexts. Design\\/methodology\\/approach – The paper employs a methodology from the field of design to identify solution requirements based on an understanding of the operational context

Carol-Ann Courneya; David Dunne

2009-01-01

159

PAH EXPOSURES OF NINE PRESCHOOL CHILDREN  

EPA Science Inventory

The exposures to 20 polycyclic aromatic hydrocarbons (PAH) of 9 children, ages 2-5 yr, were measured over 48 hr at day care and at home. Sampled media included indoor and outdoor air, floor dust, outdoor play area soil, hand surface, and solid and liquid food. Urine samples ...

160

Improved Enrichment and Isolation of Polycyclic Aromatic Hydrocarbons (PAH)Degrading Microorganisms in Soil Using Anthracene as a Model PAH  

Microsoft Academic Search

Lack of attention to soil and microbial characteristics that influence PAHs degradation has been a leading cause of failures\\u000a in isolation of efficient PAH degraders and bioaugumentation processes with microbial consortia. This study compared the classic\\u000a method of isolation of PAHs-degraders with a modified method employing a pre-enrichment respirometric analysis. The modified\\u000a enrichment of PAH degrading microorganisms using in vitro

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

2009-01-01

161

Usefulness of the organ culture system when villous height/crypt depth ratio, intraepithelial lymphocyte count, or serum antibody tests are not diagnostic for celiac disease.  

PubMed

The existence of mild forms of celiac disease (CD) can make the histology-based diagnosis difficult to reach. Since anti-endomysium (EMA) and anti-tissue transglutaminase (anti-tTG) are detectable in culture supernatants of duodenal biopsies from CD patients, our aim was to assess if this system can support the histology in the diagnostic work-up. A total of 559 suspected CD patients underwent serum EMA/anti-tTG detection, upper endoscopy with duodenal biopsy sampling, histologic analysis, and organ culture to detect EMA/anti-tTG in supernatants. A subgroup of 30 patients with organ culture positive results were put on a gluten-free diet (GFD). Their gluten-dependency was evaluated by the psychological general well-being and beck depression inventory indexes. Statistical analysis was performed by Cohen k inter-test, Friedman test, and Dunn multiple comparison. Two hundred forty-one out of 559 (43.1%) patients showed intestinal villous atrophy, whereas serum and organ culture EMA/anti-tTG were positive in 293/559 (52.4%) and 334/559 (59.7%) patients, respectively. The strength of agreement resulted good for serology vs histology (k = 0.730), good for organ culture vs histology (k = 0.662), and very good for serology vs organ culture (k = 0.852). After 12 months of GFD, psychological general well-being index significantly increased, and beck depression inventory index significantly decreased (P < 0.001 for each one). Data highlight the organ culture system as a useful tool to assist the histology in diagnosing CD, mainly in cases without villous atrophy or in seronegative patients. The marked improvement in quality of life after a GFD further supports the reliability of this system in diagnosing CD. PMID:23177794

Picarelli, Antonio; Di Tola, Marco; Marino, Mariacatia; Libanori, Valerio; Borghini, Raffaele; Salvi, Elisa; Donato, Giuseppe; Vitolo, Domenico; Tiberti, Antonio; Marcheggiano, Adriana; Bassotti, Gabrio; Corazziari, Enrico

2012-11-20

162

[Pulmonary arterial hypertension: modern diagnostics and therapy--Part 1].  

PubMed

Pulmonary arterial hypertension (PAH) belongs to the group of rare diseases and the morbidity rate is 15 to 50 people per million per year. Before the era of specific treatment of PAH, the prognosis was poor. The average life expectancy of the patients was 2.8 years. However, in the last years there has been a breakthrough in treating the patients with PAH. The introduction of this specific treatment has prolonged the life and improved the quality of it within the group of the patients with PAH. In Poland, since 2008 the therapy has been organized by the Pulmonary Hypertension Therapeutic Program. PAH is a recognition done by excluding more probable causes of pulmonary hypertension (PH) such as: PH due to left heart disease and lung disease, chronic thromboembolic pulmonary hypertension (CTEPH) and PH with multifactorial mechanisms. The clinical symptoms of pulmonary hypertension are non-specific, they develop for a several months and they are mainly caused by progressive right ventricular failure. The base of PAH recognition is echocardiography, which indirectly estimates the pulmonary artery systolic pressure. However, the golden standard of PAH diagnostics is right heart catheterization (RHC) with measurements of pulmonary arterial pressure (PAP), right atrial pressure (RAP), right ventricular pressure and pulmonary wedge pressure (PWP). The early PAH recognition and the correct classification of patients to the treatment organized by the Pulmonary Hypertension Therapeutic Program give them a chance for longer and more comfortable life. PMID:23882936

Betkier-Lipi?ska, Katarzyna; Ryczek, Robert; Kwasiborski, Przemys?aw; Cwetsch, Andrzej

2013-06-01

163

Determination of PAHs in Combustion-Related Samples and in SRM 1597, Complex Mixture of PAHs from Coal Tar  

Microsoft Academic Search

Three types of combustion sample extracts, smokeless coal, smoky coal, and wood, were analyzed for a range of polycyclic aromatic hydrocarbons (PAHs) and polycyclic aromatic sulfur heterocycles (PASH). Standard Reference Material (SRM) 1597, Complex Mixture of PAHs from Coal Tar, was also analyzed as a control sample and for the determination of a larger number of PAHs relative to those

Dianne L. Poster; Maria J. Lopez De Alda; Stephen A. Wise; Jane C. Chuang; Judy L. Mumford

2000-01-01

164

The differences of the size distribution of polycyclic aromatic hydrocarbons (PAHs) between urban and rural sites of Guangzhou, China  

NASA Astrophysics Data System (ADS)

Size distribution aerosol samples collected at two urban locations (Liwan and Wushan) and a suburban location (Xinken) in Guangzhou (South China) in autumn using a MOUDI (Micro-orifice Uniform Deposit Impactor) have been analyzed for 13 polycyclic aromatic hydrocarbons (PAHs) by gas chromatography with mass selective detection (GC-MS). Different PAH size distribution models were found for urban locations and a suburban location. The particle size distributions of PAHs tend to shift toward a larger size in a suburban location than in an urban location caused by aerosol aging processes. The ratios of total-PAH/TSP changed greatly during different sampling periods, even though the samplings were conducted consecutively. This can be the result of reactions between PAHs and atmospheric photooxidants, and the formation of SOAs (secondary organic aerosols) during the aging process. Adsorption behavior on available aerosol surface area, absorption behavior in available aerosol organic mass and multilayer adsorptive accumulation in coarse mode aerosols were the three mechanisms which control the size distribution of PAHs.

Duan, Jingchun; Bi, Xinhui; Tan, Jihua; Sheng, Guoying; Fu, Jiamo

2005-12-01

165

Rapid persulfate oxidation predicts PAH bioavailability in soils and sediments  

SciTech Connect

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

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

2000-05-15

166

Isomer distributions of molecular weight 247 and 273 nitro-PAHs in ambient samples, NIST diesel SRM, and from radical-initiated chamber reactions  

NASA Astrophysics Data System (ADS)

Molecular weight (mw) 247 nitrofluoranthenes and nitropyrenes and mw 273 nitrotriphenylenes (NTPs), nitrobenz[a]anthracenes, and nitrochrysenes were quantified in ambient particles collected in Riverside, CA, Tokyo, Japan, and Mexico City, Mexico. 2-Nitrofluoranthene (2-NFL) was the most abundant nitro-polycyclic aromatic hydrocarbon (nitro-PAH) in Riverside and Mexico City, and the mw 273 nitro-PAHs were observed in lower concentrations. However, in Tokyo concentrations of 1- + 2-NTP were more similar to that of 2-NFL. NIST SRM 1975 diesel extract standard reference material was also analyzed to examine nitro-PAH isomer distributions, and 12-nitrobenz[a]anthracene was identified for the first time. The atmospheric formation pathways of nitro-PAHs were studied from chamber reactions of fluoranthene, pyrene, triphenylene, benz[a]anthracene, and chrysene with OH and NO3 radicals at room temperature and atmospheric pressure, with the PAH concentrations being controlled by their vapor pressures. Sampling media were spiked with deuterated PAH to examine heterogeneous nitration. Comparing specific nitro-PAH ratios in ambient and diesel particles with those from our chamber experiments suggests that the low 2-NFL/NTPs ratios in Tokyo particulate matter are not a result of gas-phase radical-initiated chemistry since both gas-phase OH and NO3 radical-initiated reactions result in high 2-NFL/NTPs ratios. Comparisons of the relative formation of deuterated nitro-PAHs on the sampling media suggest that heterogeneous reactions with N2O5 on ambient particle surfaces also do not explain the nitro-PAH profiles of Tokyo particles. Thus, the source of NTPs in Tokyo remains unidentified.

Zimmermann, Kathryn; Atkinson, Roger; Arey, Janet; Kojima, Yuki; Inazu, Koji

2012-08-01

167

Photodestruction of PAHs in Planetary Nebulae  

NASA Astrophysics Data System (ADS)

It is known that polycyclic aromatic hydrocarbons (PAHs) are mainly formed in the dust shells of late stages of AGB type carbon rich stars. After the ejection of H-rich envelope those stars become the proto-planetary nebulae (PPNs). The chemistry in PPNs has been strongly modified by the UV photons coming from the hot central star and by the X-rays associated with its high-velocity winds. Benzene (C6H6) and small PAHs like Anthracene (C14H10) were effectively detected in the PPNs CRL 618 (Cernicharo et al. 2001) and Red Rectangle (Vijh, Witt & Gordon 2004) respectively. The goal of this work is to experimentally study photoabsorption, photoionization and photodissociation processes of the benzene, biphenyl (C12H10), naphthalene (C10H8), phenanthrene (C14H10) and methyl-anthracene (C14H9(CH3)). The measurements were taken at the Brazilian Synchrotron Light Laboratory (LNLS), using soft X-ray and UV photons from a toroidal grating monochromator TGM beamline (12-310 eV). The experimental set-up consists of a high vacuum chamber with a Time-Of-Flight Mass Spectrometer (TOF-MS). Mass spectra were obtained using PhotoElectron PhotoIon Coincidence (PEPICO) technique. Kinetic energy distributions and abundances for each ionic fragment have been obtained from the analysis of the corresponding peak shapes in the mass spectra. Dissociative and non-dissociative photoionization cross sections for some molecules were also determined (see for example: Boechat-Roberty, Pilling & Santos 2005). We have observed that PAHs molecules are extreme resistant to UV photons, confirming that PAHs absorb the UV photons and after some internal energetic rearrangements, they can emit in the IR range. However, these molecules are destroyed by soft X-rays photons producing several ionic fragments, some of them with great kinetic energy. In the mass spectra of the Benzene and methyl-anthracene molecules, the observed ionic fragments C4H2+, C6H2+, C4HCH3 and C2HCH3, could correspond to the same ions and radicals detected in the CRL 618 (Cernicharo et al. 2001). This result also points out the possibility of PAHs and PAHs methylated can be actively present in those environments. From the photodissociation cross sections and the stellar radiation field we have determined the photodissociation rate and the half-life, as well as its upper limit abundance of the benzene molecule in the CRL618. The relative yields of some key fragments together their observed abundances in the astrophysical target allow to estimate an upper limit of father molecules in those regions.

Boechat-Roberty, H. M.; Neves, R.; Pilling, S.; de Souza G. G., B.; Lago, A.

168

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

NASA Astrophysics Data System (ADS)

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

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

169

Relationships between PAHs and PCBs, and quantitative source apportionment of PAHs toxicity in sediments from Fenhe reservoir and watershed.  

PubMed

Sedimentary samples from 28 sites throughout the Fenhe reservoir and upstream watershed in China were measured, to study the relationships between PAHs and PCBs as well as perform quantitative source apportionment of toxicity. The distributions of ?16PAHs and ?123PCBs showed high correlation. The ?7C-PAHs (total concentrations of seven carcinogenic PAHs) varied from 87.7 to 2005.0ngg(-1)dw, and the ?6DL-PCBs (total concentrations of six dioxin-like PCB congeners) were n.d.-5.96ngg(-1)dw. Toxicity and biological risk were assessed using toxic equivalent quantity (TEQ) and sediment quality guideline quotient (SQGQ). The BaP played the dominant role for TEQPAH at most sites (37.17-89.40%), although the CHR showed the highest concentration level. PCB-81 contributed the highest TEQPCB. High correlations were observed between ?16PAHs and ?7C-PAHs, ?123PCBs and ?6DL-PCBs, ?7C-PAHs and ?6DL-PCBs as well as TEQPAH and TEQPCB. Furthermore, quantitative source apportionments for PAHs concentrations and TEQ were carried out, combining the positive matrix factorization (PMF) with the formula of TEQ. For most sites, the vehicular sources were the largest contributors to TEQPAH (46.58%), while coal combustion sources were the highest contributor for PAHs concentrations (43.31%). The relatively higher correlations between PCBs and contributions of coal combustion to PAHs might imply the similar distribution of industrial sources for PAHs and PCBs. PMID:23353932

Tian, Ying-Ze; Li, Wei-Hong; Shi, Guo-Liang; Feng, Yin-Chang; Wang, Yu-Qiu

2013-01-05

170

UNUSUAL PAH EMISSION IN NEARBY EARLY-TYPE GALAXIES: A SIGNATURE OF AN INTERMEDIATE-AGE STELLAR POPULATION?  

SciTech Connect

We present the analysis of Spitzer-IRS spectra of four early-type galaxies (ETGs), NGC 1297, NGC 5044, NGC 6868, and NGC 7079, all classified as LINERs in the optical bands. Their IRS spectra present the full series of H{sub 2} rotational emission lines in the range 5-38 {mu}m, atomic lines, and prominent polycyclic aromatic hydrocarbon (PAH) features. We investigate the nature and origin of the PAH emission, characterized by unusually low 6-9/11.3 {mu}m interband ratios. After the subtraction of a passive ETG template, we find that the 7-9 {mu}m spectral region requires dust features not normally present in star-forming galaxies. Each spectrum is then analyzed with the aim of identifying their components and origin. In contrast to normal star-forming galaxies, where cationic PAH emission prevails, our 6-14 {mu}m spectra seem to be dominated by large and neutral PAH emission, responsible for the low 6-9/11.3 {mu}m ratios, plus two broad dust emission features peaking at 8.2 {mu}m and 12 {mu}m. These broad components, observed until now mainly in evolved carbon stars and usually attributed to pristine material, contribute approximately 30%-50% of the total PAH flux in the 6-14 {mu}m region. We propose that the PAH molecules in our ETGs arise from fresh carbonaceous material that is continuously released by a population of carbon stars, formed in a rejuvenation episode that occurred within the last few Gyr. The analysis of the MIR spectra allows us to infer that, in order to maintain the peculiar size and charge distributions biased to large and neutral PAHs, this material must be shocked and excited by the weak UV interstellar radiation field of our ETGs.

Vega, O.; Bressan, A. [Instituto Nacional de Astrofisica, Optica y Electronica, Apdos. Postales 51 y 216, C.P. 72000 Puebla, Pue. (Mexico); Panuzzo, P. [CEA, Laboratoire AIM, Irfu/SAp, Orme des Merisiers, F-91191 Gif-sur-Yvette (France); Rampazzo, R.; Clemens, M.; Buson, L. [INAF Osservatorio Astronomico di Padova, vicolo dell'Osservatorio 5, 35122 Padova (Italy); Granato, G. L.; Silva, L. [INAF, Osservatorio Astronomico di Trieste, Via Tiepolo 11, I-34131 Trieste (Italy); Zeilinger, W. W., E-mail: ovega@inaoep.m [Institut fur Astronomie, Universitat Wien, Turkenschanzstrasse 17, A-1180 Wien (Austria)

2010-10-01

171

Heterogeneous oxidation and photochemistry of PAHs  

NASA Astrophysics Data System (ADS)

Until recently, the atmospheric degradation of polycyclic aromatic hydrocarbons (PAHs) was thought to occur primarily via gas phase reaction with OH or NO3. We have measured the heterogeneous oxidation kinetics of naphthalene, anthracene, fluoranthene, phenanthrene, pyrene, and benzo[a]pyrene sorbed on an "urban grime" substrate with gas phase ozone over a wide range of ozone concentrations. Including these kinetics in mass- balance models shows that they may be very important in establishing the fate of PAHs in urban environments. The photolysis rates of anthracene and naphthalene at the air-ice interface were measured, and the kinetics were compared to those observed in water solution and at the air-water interface. Reaction at the ice surface is 4-6 X faster than at the water surface, probably due to an enhancement in the absorption cross sections and/or photolysis quantum yields.

Donaldson, D.; Kahan, T. F.; Kwamena, N. A.

2007-05-01

172

Diagnostic Development on NSTX  

SciTech Connect

Diagnostics are described which are currently installed or under active development for the newly commissioned NSTX device. The low aspect ratio (R/a less than or equal to 1.3) and low toroidal field (0.1-0.3T) used in this device dictate adaptations in many standard diagnostic techniques. Technical summaries of each diagnostic are given, and adaptations, where significant, are highlighted.

A.L. Roquemore; D. Johnson; R. Kaita; et al

1999-12-16

173

Dietary exposure estimates of 16 polycyclic aromatic hydrocarbons (PAHs) in Xuanwei and Fuyuan, counties in a high lung cancer incidence area in China.  

PubMed

Xuanwei and Fuyuan are located in the southwest of China and have the highest lung cancer incidence in China, possibly even highest in the world. Dietary samples were collected from these two counties and the contamination status of sixteen polycyclic aromatic hydrocarbons (PAHs) were determined. PAH components, food constituents, dietary exposure level, as well as spatial difference, were studied in the different groups. The percentage of dietary intake to total intake of PAHs was calculated and the relationship between the dietary intake of PAHs and the abnormal lung cancer incidence was primarily discussed. The results showed that rice and potatoes were the main foods of the local residents in Xuanwei and Fuyuan. The daily exposure doses of Bap (benzo[a]pyrene), total PAHs, and TEQs (toxic equivalents) based on Bap toxicity in two counties were estimated to be 458 ng d(-1), 14,532 ng d(-1), and 896 ng d(-1), respectively, which were much less than those in other cities reported previously. The lower ingestion amount of food with a relatively higher content of PAHs, such as meat and fish, could account for the lower exposure doses. PAHs with less than 4 rings occupied a high percentage of the total PAHs in food samples. The exposure doses varied significantly among different sites and even different families at the same site. Dietary exposure was not the main exposure route of PAHs at most sites. It appears that there was not a direct relationship between dietary exposure and the lung cancer incidence. However, high ratios of dietary intake to total PAHs intake (1.33%-70.61%) were found in several areas and rational diet suggestions should be given in these areas in the future. PMID:22258356

Cai, Yanming; Lv, Jungang; Zhang, Wen; Zhang, Linlin

2012-01-19

174

Black Carbon and Sorption of PAHs in Natural Fire-Impacted Sediments From Oriole Lake (CA)  

NASA Astrophysics Data System (ADS)

We investigated the occurrence of black carbon (BC) and polycyclic aromatic hydrocarbons (PAHs) in sediment samples from Oriole Lake (Kings Canyon and Sequoia National Park, California). Sequoia National Park provided a unique environment for this study, as its frequent natural fires are recorded in the giant Sequoias. From the tree record the fire record for the past ~ 500 years is known. Having this fire recorded provides a unique opportunity to reference the sediment layers to a known fire chronology. Ca. 4 m of sediment covering the last 5,000 years were taken in July 2007 at Oriole Lake. Cores were sliced into 1 cm increments, and analyzed for 210Pb and 137Cs for dating. Samples were extracted for PAH and analyzed for organic C and BC, according to a method by Gustafsson et al. (1997). Highest BC concentrations (> 0.5% d.w.) in the last century correlated with individual forest fire events in the region. Long-range transport of traffic emissions might have contributed to a gently rising baseline of sedimentary BC concentrations. PAH ratios (e.g., methylphenanthrenes versus phenanthrenes) indicated a prevalence of pyrogenic emissions. Sediments from the last 20 years were incubated with passive PE samplers to derive porewater concentrations. Results are used to discern whether the char-rich sediments display a stronger sorption of PAHs than can be explained by the combined OC and BC pools.

Sullivan, J.; Lohmann, R.; Bollinger, K. A.; King, J.; Cantwell, M.; Caprio, T.

2008-12-01

175

Sorption and chemical transformation of PAHs on coal fly ash  

SciTech Connect

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

Mamantov, G.; Wehry, E.L.

1991-01-01

176

The 1 1S-n 1 P/1 1S-2 1 P emission-line ratios in SI XIII as electron temperature diagnostics for solar flares and active regions  

NASA Astrophysics Data System (ADS)

Theoretical Si XIII emission-line ratios R1, R2, and R3 are presented as a function of electron temperature. These ratios are found to be more electron temperature sensitive than the commonly used diagnostic for He-like ions (G), with, for example, R1, R2, and R3 varying by factors of approximately 6, 12, and 17 between log Te = 6.2 and 7.2, while G only changes by a factor of 1.8. In addition, R1, R2, and R3 are less dependent on whether or not the Si XIII-emitting plasma is in ionization equilibrium. Electron temperatures deduced using the observed values of R1, R2, and R3 from OV 1-17 and OSO 8 satellite spectra of solar flares and active regions are in good agreement and, in general, compared favorably with those determined from G. However, in the case of measurements made with the Flat Crystal Spectrometer on board the Solar Maximum Mission satellite there are large discrepancies between theory and observation. Possible explanations for these are briefly discussed.

Keenan, F. P.; McCann, S. M.; Phillips, K. J. H.

1990-11-01

177

The 1 1S-n 1 P/1 1S-2 1 P emission-line ratios in Si XIII as electron temperature diagnostics for solar flares and active regions  

SciTech Connect

Theoretical Si XIII emission-line ratios R1, R2, and R3 are presented as a function of electron temperature. These ratios are found to be more electron temperature sensitive than the commonly used diagnostic for He-like ions (G), with, for example, R1, R2, and R3 varying by factors of approximately 6, 12, and 17 between log Te = 6.2 and 7.2, while G only changes by a factor of 1.8. In addition, R1, R2, and R3 are less dependent on whether or not the Si XIII-emitting plasma is in ionization equilibrium. Electron temperatures deduced using the observed values of R1, R2, and R3 from OV 1-17 and OSO 8 satellite spectra of solar flares and active regions are in good agreement and, in general, compared favorably with those determined from G. However, in the case of measurements made with the Flat Crystal Spectrometer on board the Solar Maximum Mission satellite there are large discrepancies between theory and observation. Possible explanations for these are briefly discussed. 19 refs.

Keenan, F.P.; Mccann, S.M.; Phillips, K.J.H. (Belfast Queen's Univ. (England) Rutherford Appleton Laboratory, Didcot (England))

1990-11-01

178

AKARI Near-Infrared Spectroscopy of 3 micron PAH and 4 micron PAD features  

NASA Astrophysics Data System (ADS)

Near-infrared (NIR; 2.5-5 ?m) low-resolution (?/?? ~ 100) spectra were obtained for a number of Galactic and extragalactic objects with the Infrared Camera (IRC) in the AKARI warm mission. These data provide us with the first opportunity to make a systematic study of the 3.3-3.5 ?m PAH features in a galactic scale as well as within an object. Whereas the 3.3 ?m band is well resolved in most spectra, the 3.5 ?m band is not clearly separated from the 3.4 ?m band in the IRC spectrum. The intensity ratio of the summation of the 3.4 and 3.5 ?m bands to the 3.3 ?m band shows a tendency to increase towards the Galactic center, although a large variation in the ratio is also seen in a local scale. A search for deuterated PAH features in the 4 ?m region is carried out in IRC NIR spectra. Emission lines originating from the ionized gas together with the detector anomaly hamper an accurate search at certain wavelengths, but little convincing evidence has so far been obtained for the presence of significant features in 4.2-4.7 ?m. A conservative upper limit of a few percents is obtained for the integrated intensity ratio of the 4.4-4.7 ?m possible features to the 3.3-3.5 ?m PAH features in the spectra so far obtained.

Onaka, T.; Sakon, I.; Ohsawa, R.; Shimonishi, T.; Okada, Y.; Tanaka, M.; Kaneda, H.

2011-03-01

179

YEAR TIME MODULATION OF n-ALKANES, PAH, NITRO-PAH AND ORGANIC ACIDS AT MONTELIBRETTI ROME, ITALY  

Microsoft Academic Search

The organic fraction of airborne particulates was investigated at Montelibretti RM, Italy, over 12 months and n-alkanes, polycyclic aromatic hydrocarbons, nitrated polycyclic aromatics and aliphatic acids were evaluated. The year time modulations were acquired from all groups of compounds, both in quantitative (cumulative concentrations) and qualitative (percent compositions) terms. Some distribution indexes and diagnostic ratio rates drawn from congener abundances

A. Cecinato; C. Balducci; G. Nervegna; S. Pareti; G. Tagliacozzo; A. Brachetti

2008-01-01

180

Polycyclic Aromatic Hydrocarbon and Emission Line Ratios in Active Galactic Nuclei and Starburst Galaxies.  

NASA Astrophysics Data System (ADS)

We study the polycyclic aromatic hydrocarbons (PAH) bands, ionic emission lines, and Mid-infrared continuum properties, in a sample of 171 emission line galaxies taken from the literature plus 15 new active galactic nucleus (AGN) Spitzer spectra. The observed intensity ratios for neutral and ionized PAHs (6.2?m/7.7?m × 11.3?m/7.7?m) were compared to theoretical intensity ratios, showing that AGNs have higher ionization fraction and larger PAH molecules (? 180 carbon atoms) than SB galaxies. The ratio between the ionized (7.7?m) and the neutral PAH bands (8.6?m and 11.3?m) are distributed over different ranges for AGNs and SB galaxies, suggesting that these ratios could depend on the ionization fraction, as well as on the hardness of the radiation field. The ratio between the 7.7?m and 11.3?m bands is nearly constant with the increase of [Ne III]15.5?m/[Ne II] 12.8?m, indicating that the fraction of ionized to neutral PAH bands does not depend on the hardness of the radiation field. The equivalent width of both PAH features show the same dependence (strongly decreasing) with [Ne III]/[Ne II], suggesting that the PAH molecules, emitting either ionized (7.7?m) or neutral (11.3?m) bands, may be destroyed with the increase of the hardness of the radiation field.

Sales, D. A.; Pastoriza, M.; Riffel, R.

2011-05-01

181

PAH emission from the incineration of three plastic wastes  

Microsoft Academic Search

A batch-type, controlled-air incinerator was used for the treatment of polyvinyl chloride (PVC), high-density polyethylene (HDPE), and polypropylene (PP) plastic wastes. The concentration and composition of 21 individual polycyclic aromatic hydrocarbons (PAHs) in the raw wastes, flue gas (gas and particle phases), and ash were determined. Stack flue-gas samples were collected by a PAH stack-sampling system. Twenty-one individual PAHs were

Chun-Teh Li; Huan-Kai Zhuang; Lien-Te Hsieh; Wen-Jhy Lee; Meng-Chun Tsao

2001-01-01

182

PAHs and the ISM in Metal-Poor Starbursts  

NASA Astrophysics Data System (ADS)

We characterize PAH populations in 22 metal-poor blue compact dwarf galaxies (BCDs), 16 of which have an oxygen abundance 12+log(O/H) ? 8. This is the largest sample ever studied at such low metallicities. The relative PAH intensities of the 6.2, 7.7, 8.6 and 11.3 ?m features in these BCDs suggest a deficit of small PAH carriers, or alternatively, an excess of large ones at these low abundances.

Hunt, L. K.; Izotov, Y. I.; Sauvage, M.; Thuan, T. X.

2011-03-01

183

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  

Microsoft Academic Search

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

Anders R. Johnsen; Stine Schmidt; Trine K. Hybholt; Sidsel Henriksen; Carsten S. Jacobsen; Ole Andersen

2007-01-01

184

Distribution and occurence of polycyclic aromatic hydrocarbons (PAHs) in sediments from the Mar Grande and Gulf of Taranto (Ionian Sea, southern Italy).  

PubMed

Marine sediments from the Mar Grande and Gulf of Taranto were analysed for 17 parent PAHs, with molecular weight from 128 to 278 Daltons. The analyses were performed by gas chromatography coupled to mass spectrometry (GC-MS). Total PAHs content in sediments ranged from 464 to 12522 microg kg(-1) dry wt for Mar Grande and from 593 to 72275 microg kg(-1) dry wt for Gulf of Taranto. The analytical results were compared with the published results for other coastal areas in the Mediterranean Sea. PAHs levels in the Gulf of Taranto sediments were the highest in the Mediterranean sea, while PAHs concentrations in Mar Grande were higher than the ones reported in the Adriatic and Cretan Sea and with the same order of magnitude of the ones known for coastal areas of the Western and the Eastern Mediterranean Sea. PAHs concentration ratios were consistent with the main source of these compounds, in most areas, being pyrolysis. Based on the comparison of both the individual and the total PAHs concentrations with proposed sediment quality guidelines, the acute biological effects on the marine organisms were probable, especially for the Gulf of Taranto, in which almost all PAHs concentrations in sediments were higher than the guidelines limit values. The statistical analysis effected by HCA and PCA methods was used in order to classify sediment samples and to identify accumulation areas. PMID:16734022

Cardellicchio, Nicola; Buccolieri, Alessandro; Giandomenico, Santina; Lerario, Vito Luigi; Lopez, Luigi; Pizzulli, Filomena

185

Modelling the behaviour of PAHs during atmospheric transport from the UK to the Arctic  

NASA Astrophysics Data System (ADS)

Persistent organic pollutants (POPs) such as PAHs are subject to long-range atmospheric transport, which can result in the contamination of remote areas such as the Arctic. A simple model was developed to describe the removal processes of four PAHs; fluorene (FLU), phenanthrene (PHEN), fluoranthene (FLA) and benzo[a]pyrene (B[a]P) transported over a 5 day period from a source area over the UK to the Russian Arctic. The purpose of this model was to study processes affecting the PAHs within the atmosphere, rather than their interaction with the earth's surface. The components to the model included gas/particle partitioning, reaction with OH radicals and dry and wet deposition (both rain and snow). Atmospheric/meteorological parameters for the geographical region of interest were generated from three-dimensional atmospheric models. Air concentrations were prescribed in the source area with no additional PAH inputs along the transect, both winter and summer scenarios were modelled. Reaction with OH was a major removal mechanism for gas-phase FLU, PHEN and FLA, most notably in the temperate atmosphere. Wet deposition in the form of snow accounted for the majority of PAH loss in the winter, although the gas and particle scavenging ratios used in this model ranged over several orders of magnitude. Using a 5 day transport scenario in a `1-hop' event, the model predicted that a primary emission of FLA and B[a]P to the atmosphere of the southern UK, would not reach the Russian Arctic at a distance of ˜3500 km, assuming a constant windspeed of 10 m s -1. However, both FLU and PHEN with calculated half-lives of >60 h during the winter could be transported to this area under this scenario.

Halsall, C. J.; Sweetman, A. J.; Barrie, L. A.; Jones, K. C.

186

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

PubMed

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

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

2006-05-01

187

Atmospheric concentrations, dry deposition and air–soil exchange of polycyclic aromatic hydrocarbons (PAHs) in an industrial region in Turkey  

Microsoft Academic Search

Concurrent ambient air and dry deposition samples were collected during two sampling periods at the Aliaga industrial region in Izmir, Turkey. ?15-PAH (particulate+gas) concentrations ranged between 7.3 and 44.8ngm?3 (average±S.D., 25.2±8.8ngm?3) and 10.2–71.9ngm?3 (44.1±16.6ngm?3) in summer and winter, respectively. Winter\\/summer individual ambient PAH concentration ratios ranged between 0.8 (acenaphthene) and 6.6 (benz[a]anthracene) indicating that wintertime concentrations were affected by residential

Ayse Bozlaker; Aysen Muezzinoglu; Mustafa Odabasi

2008-01-01

188

PAH Intermediates: Links between the Atmosphere and Biological Systems  

PubMed Central

China is now the world's largest emitter of polycyclic aromatic hydrocarbons (PAHs). In addition, PAHs, and their reactive intermediates, undergo trans-Pacific atmospheric transport to the Western U.S. The objectives of our research are to predict, identify and quantify novel PAH intermediates in the atmosphere and biological systems, using computational methods, as well as laboratory and field experiments. Gaussian is used to predict the thermodynamic properties of parent structure PAHs, as well as the associated nitro-, oxy-, and hydroxy- PAH intermediates. Based on these predictions, state-of-the-art analytical chemistry techniques are used to identify and quantify these potential intermediates on Asian particulate matter before and after reaction in a continuous flow photochemical reactor. These same techniques are used to identify the relative proportion of PAH intermediates in PAH source regions (such as Beijing, China) and during long-range atmospheric transport to the Western U.S. PAH personal exposure studies in China and the Confederated Tribes of the Umatilla Indian Reservation in Oregon will be used to assess the similarities and differences in the PAH intermediates in biological systems relative to the atmosphere.

SIMONICH, STACI L. MASSEY; MOTORYKIN, OLEKSII; JARIYASOPIT, NARUMOL

2010-01-01

189

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

PubMed

In the wake of the 1989 Exxon Valdez oil spill, spatially and temporally spill-correlated biological effects consistent with polycyclic aromatic hydrocarbon (PAH) exposure were observed. Some works have proposed that confounding sources from local source rocks, prominently coals, are the provenance of the PAHs. Representative coal deposits along the southeast Alaskan coast (Kulthieth Formation) were sampled and fully characterized chemically and geologically. The coals have variable but high total organic carbon content technically classifying as coals and coaly shale, and highly varying PAH contents. Even for coals with high PAH content (approximately 4000 ppm total PAHs), a PAH-sensitive bacterial biosensor demonstrates nondetectable bioavailability as quantified, based on naphthalene as a test calibrant. These results are consistent with studies indicating that materials such as coals strongly diminish the bioavailability of hydrophobic organic compounds and support previous work suggesting that hydrocarbons associated with the regional background in northern Gulf of Alaska marine sediments are not appreciably bioavailable. PMID:19731689

Deepthike, Halambage Upul; Tecon, Robin; Van Kooten, Gerry; Van der Meer, Jan Roelof; Harms, Hauke; Wells, Mona; Short, Jeffrey

2009-08-01

190

Improved GC\\/MS methods for measuring hourly PAH and nitro-PAH concentrations in urban particulate matter  

Microsoft Academic Search

This study presents two methods for the quantification of nitro-substituted and parent polycyclic aromatic hydrocarbons (NPAH and PAH, respectively), respectively, utilizing large volume injection gas chromatography\\/mass spectrometry (GC\\/MS). Both methods (PAH and NPAH, respectively) employed a programmed temperature vaporization injector (PTV) in solvent vent mode, optimized using standard solutions. For the PAH method, the precision of the PTV was comparable

Bernard S. Crimmins; Joel E. Baker

2006-01-01

191

Effects of heterocyclic PAHs (N, S, O) on the biodegradation of typical tar oil PAHs in a soil \\/ compost mixture  

Microsoft Academic Search

The interaction phenomena during the biodegradation of typical coal tar polycyclic aromatic hydrocarbons and their heterocyclic analogues (N, S, O) were investigated in an artificially contaminated AhA1-horizon\\/compost mixture. All compounds were partly or completely biodegraded. Degradation of two- to five-ring PAHs was inhibited by the presence of hetero-PAHs, whereas degradation of just some hetero-PAHs was inhibited by the presence of

Susanne Meyer; Hans Steinhart

2000-01-01

192

Hydroxynitro-PAH and other PAH derivatives in California's atmosphere and their contribution to ambient mutagenicity. Final report  

SciTech Connect

Nitro-PAH lactones formed in the air by reactions of polycyclic aromatic hydrocarbons (PAHs) and nitrogen oxide gases, may be responsible for a significant portion of the mutagenicity of particulate matter present in California's atmosphere. Simulating ambient California air, smog chamber studies were conducted on three PAHs: naphthalene, fluorene, and phenanthrene. The resulting chamber contents were fractioned by liquid chromatography. The most mutagenic fractions were chemical analyzed.

Atkinson, R.; Arey, J.

1991-08-01

193

PAHs as Tracers of Local AGN-Starburst Connection  

NASA Astrophysics Data System (ADS)

The main purpose of this research was to investigate how energetic processes associated with active galactic nuclei (AGN) are related to those due to nuclear or circumnuclear star formation activity. Photometric and spectroscopic data were used to discriminate between these processes in a sample of starburst, infrared galaxies and AGNs. Here, we propose new diagnostic diagrams based on the 7.7 ?m polycyclic aromatic hydrocarbon emission band, the L(MIR,FIR) infrared ratio and the q parameter. The diagnostic diagrams allow us to discriminate the behavior of quasars and Seyfert 1-Seyfert 2 galaxies from starbursts and LIRGs-ULIRGs objects.

Higuera-G., M.-A.; Ramos P., A. F.

2013-10-01

194

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

PubMed

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. The urinary PAH metabolite content did not show the same spatial trends as biliary PAH metabolites. However, fish from Aarhus Bight and Vejle Fjord had significantly higher levels of PAH metabolites in both urine and bile compared to the reference station Agersø. Normalisation methods applied for bile and urine matrices did not have any effect or only slightly reduced the coefficients of variation in data sets. The CYP1A activity in eelpout liver did not show the same spatial distribution trends between sampling sites as did biliary or urinary PAH metabolite contents. Male eelpouts showed significantly higher CYP1A activity than females in fall sampling period but there were no differences found in the spring period. General comparison between both seasons showed that eelpouts sampled in the fall had significantly higher CYP1A activity than fish sampled during spring season. Overall, the results of this study describe selected biomarker responses in eelpouts to environmental PAH load at the different areas along Danish coasts. PMID:21982560

Tairova, Zhanna M; Strand, Jakob; Chevalier, Julie; Andersen, Ole

2011-09-25

195

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

NASA Astrophysics Data System (ADS)

The spectra of neutral and ionized PAHs isolated in the gas phase at low temperature have been measured in the laboratory under conditions that mimic interstellar conditions and are compared with a set of astronomical spectra of reddened, early type stars. The comparisons of astronomical and laboratory data provide upper limits for the abundances of neutral PAH molecules and ions along specific lines-of-sight. Something that is not attainable from infrared observations. We present the characteristics of the laboratory facility (COSmIC) that was developed for this study and discuss the findings resulting from the comparison of the laboratory data with high resolution, high S/N ratio astronomical observations. COSmIC combines a supersonic jet expansion with discharge plasma and cavity ringdown spectroscopy and provides experimental conditions that closely mimic the interstellar conditions. The column densities of the individual PAH molecules and ions probed in these surveys are derived from the comparison of the laboratory data with high resolution, high S/N ratio astronomical observations. The comparisons of astronomical and laboratory data lead to clear conclusions regarding the expected abundances for PAHs in the interstellar environments probed in the surveys. Band profile comparisons between laboratory and astronomical spectra lead to information regarding the molecular structures and characteristics associated with the DIB carriers in the corresponding lines-of-sight. These quantitative surveys of neutral and ionized PAHs in the optical range open the way for quantitative searches of PAHs and complex organics in a variety of interstellar and circumstellar environments. Acknowledgements: F.S. acknowledges the support of the Astrophysics Research and Analysis Program of the NASA Space Mission Directorate and the technical support provided by R. Walker at NASA ARC. J.K. acknowledges the financial support of the Polish State. The authors are deeply grateful to the ESO archive as well as to the ESO staff members for their active support.

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

2013-06-01

196

The use of limpets as monitor of PAHs pollution in the Cantabrian coast  

NASA Astrophysics Data System (ADS)

The concentrations of 24 parental and methylated polycyclic aromatic hydrocarbon (PAH) levels in common limpet ( Patella vulgata) were measured in 15 coastal localities of the southern Bay of Biscay and 2 sites per locality for 2 years (spring and autumn of 2004 and 2005, respectively). Although the average concentrations shown a wide variability among the sites and the season, several sites showed a remarkable high concentration (PAH tot>900 ng g -1 d.w.) or medium (300-800 ng g -1 d.w) levels, but in most of the cases the initial high concentrations decreased sharply from one campaign to the following. Moreover, based on ratios of individual isomers concentration, petrogenic and pyrolitic sources were distinguished suggesting more than one source. Finally, based on the results of this work and comparing with previously reported data, it can concluded that limpets can be used as sentinel organisms in coastal environmental monitoring, even when oil spills are involved.

Bartolomé, L.; Bustamante, M.; Navarro, P.; Tajadura, J.; Gorostiaga, J. M.; Díez, I.; Zuloaga, O.; Etxebarria, N.

2011-11-01

197

Determination of PAHs in particulate air by micellar liquid chromatography  

SciTech Connect

An acetonitrile/0.20M SDS mobile phase was used to determine PAHs by HPLC with fluorimetric detection. Because the peak area is greater the method is more sensitive than using an acetonitrile/water mobile phase. The method was applied to determine PAHs in particulate air samples and the results are in good agreement with those found by GC.

Kayali, M.N.; Rubio-Barroso, S.; Polo-Diez, L.M. (Complutense Univ. of Madrid (Spain). Dept. of Analytical Chemistry)

1994-01-01

198

Polycyclic Aromatic Hydrocarbon (PAH) Ecotoxicology in Marine Ecosystems  

Microsoft Academic Search

Low levels of oil and hence polycyclic aromatic hydrocarbons (PAHs) are naturally present in the marine environment, although levels have increased significantly following human extraction and use of oil and gas. Other major anthropogenic sources of PAHs include smelters, the use of fossil fuels in general, and various methods of waste disposal, especially incineration. There are two major sources for

Ketil Hylland

2006-01-01

199

Modeling Surfactant LAS Influenced PAHs Migration in Soil Column  

Microsoft Academic Search

The objective of the present work was to study the transport of Polycyclic Aromatic Hydrocarbons (PAHs) in artificially contaminated and oil field soil columns while Linear Alkylbenzene Sulfonate (LAS) was used as leaching solvent. Through soil column leaching experiments, the through curves (BTCs) of the tracer (Br?) and PAHs were obtained. The batch equilibrium experiments were conducted. The partition coefficients,

J. Chen; X. J. Wang; J. D. Hu; S. Tao

2006-01-01

200

Competition in the Pharmaceutical Industry: The Case of PAH Drugs  

Microsoft Academic Search

The nature and extent of competition between different therapies for a given medical condition often is an important and controversial issue in both antitrust cases and general strategic analysis in the pharmaceutical industry. The market for pulmonary arterial hypertension (‘PAH’) therapies provides an interesting case study for analyzing these issues. An event study analyzing how the stock prices of PAH

Kevin C. Green

2009-01-01

201

The PAH and organic content of sediment particle size fractions  

Microsoft Academic Search

The relationship of nine Polycyclic Aromatic hydrocarbons (PAH) with organic matter present in various river sediment size fractions, from 63 µm to 1.0 to 2.0 mm, has been investigated. It is suggested that the PAH and organic matter content have bimodal distributions through the sediment size fractions which may be explained by the presence of two types of organic material

K. M. Evans; R. A. Gill; P. W. J. Robotham

1990-01-01

202

Profiles of PAH emission from steel and iron industries  

Microsoft Academic Search

In order to characterize the polycyclic aromatic hydrocarbons (PAHs) emission from steel and iron industries, this study measured the stack emission of twelve steel and iron plants in southern Taiwan to construct a set of source fingerprints. The study sampled the emissions by the USEPA's sampling method 5 with the modification of Graseby for the gas and particulate phase PAH

Hsi-Hsien Yang; Soon-Onn Lai; Lien-Te Hsieh; Hung-Junt Hsueh; Tze-Wen Chi

2002-01-01

203

Polycyclic aromatic hydrocarbons (PAH) in seawater around England and Wales  

Microsoft Academic Search

Surface seawater samples collected during the period 1993–1995 from 177 stations around England and Wales have been analysed for 15 individual parent PAH compounds, using high-performance liquid chromatography with fluorescence detection. The sampling sites included 50 of the stations designated under the UK National Monitoring Programme, and comprised estuarine, coastal and offshore locations. PAH concentrations at offshore sites were generally

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

1997-01-01

204

Determination of Heavy Polycyclic Aromatic Hydrocarbons (PAH) in Fishery Products  

Microsoft Academic Search

Polycyclic aromatic hydrocarbons (PAH) determination in a food matrix is a topic of interest for routine quality control or screening analyses. For currently available methods, sample preparation is laborious and time-consuming.The determination of PAH in fishery products developed in this paper is based on Conte and Moret's method for vegetable oils. Fat is extracted from 2 g of dehydrated sample,

Cristina Sobrado; Ma Corina Quintela; José C. González; Juan M. Vieites

2004-01-01

205

Nanoporous Polymeric Material for Remediation of PAHs Polluted Water  

Microsoft Academic Search

A new nanoporous polymer was prepared using non covalent molecular imprinting technique to remediate PAHs contaminated water. The molecularly imprinted polymer (MIP) microspheres size range between 10 and 20 ?m were synthesized in acetonitrile using 4 PAHs mix as the template, methacrylic acid as the functional monomer, and ethylene glycol dimethacrylate as the cross-linking monomer. The removal efficiency of the

REDDITHOTA J. KRUPADAM

2012-01-01

206

Polycyclic aromatic hydrocarbons (PAHs) in livers of California sea otters.  

PubMed

Concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) were measured in livers of 81 adult female sea otters collected along the California coast in 1992-2002. Concentrations of summation operatorPAHs in livers of sea otters were in the range of 588-17400ng/g lipid wt (mean: 3880ng/g, lipid wt). On a wet weight basis, the concentrations ranged from 17 to 1430ng/g (mean: 146ng/g). Overall, di- and tri-cyclic aromatic hydrocarbons, namely, naphthalene, fluorene, phenanthrene/anthracene, and acenaphthylene, were the predominant compounds found in the livers. Although petroleum-related sources appear to be the major contributors to PAH exposure in sea otters, exposure sources varied by geographical sub-regions. Dibenz[a,h]anthracene was found to comprise a significant proportion of the summation operatorPAH concentrations in sea otters from the northern sub-region of the study area. No significant difference existed in the concentrations of summation operatorPAHs among sea otters that died from infectious diseases, emaciation, and noninfectious causes. Concentrations of summation operatorPAHs in livers of sea otters decreased significantly from 1992 to 2002. Because of the rapid metabolism of PAHs in marine mammals such as sea otters, further studies examining the association of PAHs with health effects should determine hydroxylated metabolites in livers. PMID:18177687

Kannan, Kurunthachalam; Perrotta, Emily

2008-01-03

207

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

SciTech Connect

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

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

2007-01-01

208

ARIZONA BORDER STUDY--PAH IN REPLICATES ANALYTICAL RESULTS  

EPA Science Inventory

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

209

CHILDREN'S AGGREGATE EXPOSURE TO POLYCYCLIC AROMATIC HYDROCARBONS (PAHS)  

EPA Science Inventory

Polycyclic aromatic hydrocarbons (PAHs) have been frequently detected at children's homes and day care centers and may pose health concerns due to their carcinogenicity. Most PAHs have been persistent indoors and outdoors, therefore, children may be exposed to chronic low level...

210

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

NASA Astrophysics Data System (ADS)

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

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

2009-12-01

211

Size distribution and dry deposition of road dust PAHs  

SciTech Connect

The size distribution of polycyclic aromatic hydrocarbons (PAHs) for road dust and for the engine exhaust of both gasoline-powered cars and motorcycles was investigated. In addition, by using the measured size distribution data, monitoring and modeling the PAH dry deposition, the contribution fraction of road dust on the dry deposition materials was also studied. Twenty-one PAHs were analyzed primarily by using a gas chromatograph/mass spectrometer (GC/MS). The mass median diameters (MMDs) of 21 individual PAHs for resuspendable road dust (cut size < 100 {micro}m) ranged between 63.4 {micro}m and 65.5 {micro}m. However, the MMDs of total-PAH size distributions for the engine exhaust of both gasoline-powered cars and four-stroke motorcycles averaged 0.45 {micro}m and 0.35 {micro}m, respectively, which were near the MMDs of PAHs (average 0.50 {micro}m) in the ambient air of traffic intersections. Suspended particle-phase total PAHs in the ambient air of traffic intersections were found to be more than 90% of the result of the automobile exhaust; that is, less than 10% of the amount was contributed by the road dust. However, the modeled MMDs of 21 individual PAHs on the dry deposition material were between 22.1 {micro}m and 44.6 {micro}m, and the contribution fraction of road dust on the PAH dry deposition was found to be more than 95%, even though the suspendable ambient-air PAHs were mainly from the mobile exhaust.

Yang, H.H.; Chiang, C.F. [Chaoyang Univ. of Technology, Taichung (Taiwan, Province of China). Dept. of Environmental Management; Lee, W.J. [National Cheng Kung Univ., Tainan (Taiwan, Province of China). Dept. of Environmental Engineering; Hwang, K.P. [National Cheng Kung Univ., Tainan (Taiwan, Province of China). Dept. of Transportation and Communication Management; Wu, E.M.Y. [Kaohsiung Municipal Government (Taiwan, Province of China). Dept. of Environmental Protection

1999-07-01

212

Modulation of the Effect of Prenatal PAH Exposure on PAH-DNA Adducts in Cord Blood by Plasma Antioxidants  

PubMed Central

The fetus is more susceptible than the adult to the effects of certain carcinogens, such as polycyclic aromatic hydrocarbons (PAH). Nutritional factors, including antioxidants, have been shown to have a protective effect on carcinogen-DNA adducts and cancer risk in adults. We investigated whether the effect of prenatal airborne PAH exposure, measured by personal air monitoring during pregnancy, on the level of PAH-DNA adducts in a baby's cord blood is modified by the concentration of micronutrients in maternal and cord blood. The micronutrients examined were: retinol (vitamin A), ?-tocopherol and ?-tocopherol (vitamin E), and carotenoids. With the use of multiple linear regression, we found a significant interaction between prenatal PAH exposure and cord blood concentration of ?-tocopherol and carotenoids in predicting the concentration of PAH adducts in cord blood. The association between PAH exposure and PAH adducts was much stronger among those with low ?-tocopherol (? = 0.15; P = 0.001) and among those with low carotenoids (? = 0.16; P < 0.001) compared with babies with high levels of these micronutrients (among those with high ?-tocopherol: ? = 0.05; P = 0.165; among those with high carotenoids: ? = 0.06; P = 0.111). These results suggest a protective effect of micronutrients on the DNA damage and potential cancer risk associated with prenatal PAH exposure.

Kelvin, Elizabeth A.; Edwards, Susan; Jedrychowski, Wieslaw; Schleicher, Rosemary L.; Camann, David; Tang, Deliang; Perera, Frederica P.

2011-01-01

213

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

Microsoft Academic Search

Motor vehicles are a significant source of airborne polycyclic aromatic hydrocarbons (PAH) in many urban areas. Traditional approaches used in determining the relative contributions of individual vehicle types to the total amount of PAH in air have been based on the analysis of integrated samples of airborne particles and gases for the presence of chemical tracers indicative of the vehicles

Jana C Dunbar; Chen-I Lin; Isaura Vergucht; Jeffery Wong; John L Durant

2001-01-01

214

Effects of air\\/fuel combustion ratio on the polycyclic aromatic hydrocarbon content of carbonaceous soots from selected fuels  

Microsoft Academic Search

Patterns of polycyclic aromatic hydrocarbon (PAH) content were observed from GC\\/MS analysis of the extracts of soots at various air\\/fuel combustion ratios of three commonly used fuels: n-hexane, JP-8 (Jet fuel), and diesel. With increasing air\\/fuel ratio, from a simple diffusion flame up to an air\\/fuel ratio of 3.94, there is a significant loss of high molecular weight PAHs and

C. C. Jones; A. R. Chughtai; B. Murugaverl; D. M. Smith

2004-01-01

215

Ozone oxidation of surface-adsorbed polycyclic aromatic hydrocarbons (PAHs): Role of PAH-surface interaction  

NASA Astrophysics Data System (ADS)

We examine the effects of substrate on the oxidation of surface-bound anthracene and pyrene by gas-phase O3 using density functional theory (B3LYP/6-31g**). We find that the PAH-substrate interaction may result in the inhibition of some oxidation pathways involving nonplanar intermediates. The energy penalty for partial detachment from the surface is estimated and accounted for in the thermodynamic analysis of the reaction pathways. For anthracene, at least one oxidation pathway may be inhibited by strong interaction with the surface, thus impacting the rate of anthraquinone formation and possibly the observed rate of anthracene loss due to oxidation. Furthermore, the formation of other nonplanar products which have been proposed previously may be inhibited. When larger PAHs such as pyrene are surface-adsorbed, ring-opening reactions that proceed via the Criegee mechanism may be inhibited.

McNeill, V. Faye; Chu, Sophie; Sands, Sophia; Tomasik, Michelle

2010-05-01

216

Distribution of polycyclic aromatic hydrocarbons (PAHS) and phenolic endocrine disrupting chemicals in South and Southeast Asian mussels.  

PubMed

A comprehensive monitoring survey for polycyclic aromatic hydrocarbons (PAHs) and phenolic endocrine disrupting chemicals (EDCs) utilizing mussels as sentinel organisms was conducted in South and Southeast Asia as a part of the Asian Mussel Watch project. Green mussel (Perna viridis) samples collected from a total of 48 locations in India, Indonesia, Singapore, Malaysia, Thailand, Cambodia, Vietnam, and the Philippines during 1994-1999 were analyzed for PAHs, EDCs including nonylphenol (NP), octylphenol (OP) and bisphenol A (BPA), and linear alkylbenzenes (LABs) as molecular markers for sewage. Concentrations of NP ranged from 18 to 643 ng/g-dry tissue. The highest levels of NP in Malaysia, Singapore, the Philippines, and Indonesia were comparable to those observed in Tokyo Bay. Elevated concentrations of EDCs were not observed in Vietnam and Cambodia, probably due to the lower extent of industrialization in these regions. No consistent relationship between concentrations of phenolic EDCs and LABs were found, suggesting that sewage is not a major source of EDCs. Concentrations of PAHs ranged from 11 to 1,133 ng/g-dry, which were categorized as "low to moderate" levels of pollution. The ratio of methylphenanthrenes to phenanthrene (MP/P ratio) was >1.0 in 20 out of 25 locations, indicating extensive input of petrogenic PAHs. This study provides a bench-mark for data on the distribution of anthropogenic contaminants in this region, which is essential in evaluating temporal and spatial variation and effect of future regulatory measures. PMID:17370135

Isobe, Tomohiko; Takada, Hideshige; Kanai, Miki; Tsutsumi, Shinobu; Isobe, Kei O; Boonyatumanond, Ruchaya; Zakaria, Mohamad Pauzi

2007-03-17

217

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

PubMed

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

Haritash, A K; Kaushik, C P

2009-04-07

218

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

NASA Astrophysics Data System (ADS)

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

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

2011-03-01

219

Sorption and chemical transformation of PAHs on coal fly ash  

SciTech Connect

The objective of this research is to characterize the interactions of coal fly ash with polycyclic aromatic hydrocarbons (PAHs) and their derivatives, and to understand the influence of the surface properties of coal ash (and other atmospheric particles) on the chemical transformations of polycyclic aromatic compounds. During the past year the following specific aspects of this broad problem area have been investigated: (a) Fractionation of heterogeneous coal fly ash samples into different particle types varying in size and chemical composition (carbonaceous, mineral-magnetic, and mineral nonmagnetic); (b) The use of gas-solid chromatography to measure heats of sorption of PAHS, and PAH derivatives, on coal fly ashes and ash fractions. (c) Identification of the major photoproduct(s) of the photodecomposition of one PAH (benz[a]anthracene) sorbed on model adsorbents; (d) Estimation of fractal dimensions'' of coal fly ash particles by use of specific surface area measurements, with an ultimate objective of using these measurements to assess the importance of inner-filter effects'' on the photodecomposition of PAHs sorbed on fly ash particles. (e) The photochemical transformation of a representative nitro-PAH derivative (1-nitropyrene) sorbed on fly ash. (f) Development of techniques for studying the nonphotochemical reactions of hydroxyl radicals (and other atmospheric constituents) with PAHs sorbed on fly ash. Progress achieved, and problems encountered, in each of these major areas of emphasis is described below.

Mamantov, G.; Wehry, E.L.

1992-01-01

220

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.  

PubMed

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. A nonprimed control microcosm containing pristine soil artificially polluted with PAHs showed only small increases in the numbers of culturable PAH degraders and no pdo1 genes. Initial PAH degradation rates were highest in the primed microcosm, but later, the degradation rates were comparable in primed and nonprimed soil. Thus, the proliferation and persistence of the introduced, soil-adapted degraders had only a marginal effect on PAH degradation. Given the small effect of priming with bioremediated soil and the likely presence of PAH degraders in almost all PAH-contaminated soils, it seems questionable to prime PAH-contaminated soil with bioremediated soil as a means of large-scale soil bioremediation. PMID:17209064

Johnsen, Anders R; Schmidt, Stine; Hybholt, Trine K; Henriksen, Sidsel; Jacobsen, Carsten S; Andersen, Ole

2007-01-05

221

Photoinduced degradation of PAHs in the presence of ozone  

SciTech Connect

Polycyclic Aromatic Hydrocarbons (PAH) are formed from both anthropogenic and natural sources. In order to assess the environmental impact caused by the surface-adsorbed PAHs, the chemical lifetimes of these compounds in the atmosphere must be determined. Although ozone is known to be a primary reactant in the chemical transformation of surface-adsorbed PAHs in the atmosphere, the kinetics of these reactions have not been investigated in detail. In addition to the experimental difficulties that arise in using an oxygen-ozone stream while monitoring the PAH with fluorescence, complications in analyzing the kinetic mechanism also exist. It is difficult to determine whether the ozone or oxygen initially quenches the excited state of PAH. Ozone could enhance the degradation rate by simply reacting with a product derived from the excited state of PAH and oxygen. The focus of this study is to demonstrate the use of fluorescence spectroscopy in monitoring the degradation of PAH adsorbed on a three dimensional particle in the presence of gaseous ozone free from the interference of oxygen. More specifically, the experimental procedure will involve the generation of an ozone-nitrogen gas stream to be used in the investigation of dark and photochemical reactions between ozone and naphthalene. The absence of oxygen in the system will allow for the accurate monitoring of PAH fluorescence decay due solely to ozone quenching. It will also aid in the determination of the reaction mechanism. This is the first time that the direct interaction of ozone with an excited state of PAH has been demonstrated.

Schutt, W.S.; Li, Y. [Clarkson Univ., Potsdam, NY (United States). Dept. of Chemistry; Sigman, M.E. [Clarkson Univ., Potsdam, NY (United States). Dept. of Chemistry]|[Oak Ridge National Lab., TN (United States). Chemistry Div.

1995-12-31

222

Signature of [SiPAH]+ ?-complexes in the interstellar medium  

NASA Astrophysics Data System (ADS)

Aims: We investigate the presence of silicon atoms adsorbed on the surface of interstellar polycyclic aromatic hydrocarbons (PAHs) to form SiPAH ?-complexes. Methods: We used quantum chemistry calculations to obtain the structural, thermodynamic, and mid-IR properties of neutral and cationic SiPAH ?-complexes. Results: The binding energy was found to be at least 1.5 eV for [SiPAH]+ complexes, whereas it is ~0.5 eV for their neutral counterparts. From the spectral analysis of the calculated IR spectra, we found that the coordination of Si to PAH+ does not strongly affect the intensities of the PAH+ spectra, but systematically introduces blueshifts of the C-C in-plane and the C-H out-of-plane bands. Conclusions: The thermodynamic data calculated for [SiPAH]+ complexes show that these species are stable and can be easily formed by radiative association of Si+ and PAH species that are known to be abundant in photodissociation regions. Their mid-IR fingerprints show features induced by the coordination of Si that could account for (i) the blueshifted position of the 6.2 ?m AIB and (ii) the presence of satellite bands observed on the blue side of the 6.2 and 11.2 ?m AIBs. From such an assignment, we can deduce that typically 1% of the cosmic Si appears to be attached to PAHs. This work is based on observations made with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, The Netherlands, and the UK) and with the participation of ISAS and NASA.

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

2009-02-01

223

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

SciTech Connect

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

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

1985-02-01

224

[Effects of soil PAHs pollution on plant ecophysiology].  

PubMed

Polycyclic aromatic hydrocarbons (PAHs) are the ubiquitous organic persistent pollutants in natural environments (especially in soil), giving serious potential risks to the eco-environment, plants, and human beings. At present, the remediation of PAHs-polluted soil is one of the hot topics in the research fields of soil and environment. Phytoremediation is one of the environmental restoration techniques with most potentiality. This paper reviewed the newest progress in the researches of the effects of soil PAHs pollution and its combined stress with other pollutants on the plant growth, morphological structure, photosynthesis, and antioxidant system, and prospected the important fields and hotspots of related researches in the future. PMID:24015545

Xu, Sheng; Wang, Hui; Chen, Wei; He, Xing-Yuan; Su, Dao-Yan; Li, Bo; Li, Mei

2013-05-01

225

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

PubMed

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

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

2013-04-30

226

PAHs, PAH-induced carcinogenic potency, and particle-extract-Induced cytotoxicity of traffic-related nano/ultrafine particles.  

PubMed

Polycyclic aromatic hydrocarbons (PAHs) bound in nano/ ultrafine particles from vehicle emissions may cause adverse health effects. However, little is known about the characteristics of the nanoparticle-bound PAHs and the PAH-associated carcinogenic potency/cytotoxicity; therefore, traffic-related nano/ultrafine particles were collected in this study using a microorifice uniform deposition impactor(MOUDI) and a nano-MOUDI. For PM0.056--18, the difference in size-distribution of particulate total-PAHs between non-after-rain and after-rain samples was statistically significant at alpha = 0.05; however, this difference was not significant for PM0.01--0.056. The PAH correlation between PM0.01--0.1 and PM0.1--1.8 was lower for the after-rain samples than forthe non-after-rain samples. The average particulate total-PAHs in five samplings displayed a trimodal distribution with a major peak in the Aitken mode (0.032--0.056 microm). About half of the particulate total-PAHs were in the ultrafine size range. The BaPeq sums of BaP, IND, and DBA (with toxic equivalence factors > or = 0.1) accounted for approximately 90% of the total-BaPeq in the nano/ultrafine particles, although these three compounds contributed little to the mass of the sampled particles. The mean content of the particle-bound total-PAHs/-BaPeqs and the PAH/BaPeq-derived carcinogenic potency followed the order nano > ultrafine > fine > coarse. For a sunny day sample, the cytotoxicity of particle extracts (using 1:1 (v/v) n-hexane/dichloromethane) was significantly higher (p < 0.05) for the nano (particularly the 10-18 nm)/ultrafine particles than for the coarser particles and bleomycin. Therefore, traffic-related nano and ultrafine particles are possibly cytotoxic. PMID:18589992

Lin, Chih-Chung; Chen, Shui-Jen; Huang, Kuo-Lin; Lee, Wen-Jhy; Lin, Wen-Yinn; Tsai, Jen-Hsiung; Chaung, Hso-Chi

2008-06-01

227

Sorption and chemical transformation of PAHs on coal fly ash. Final technical report  

SciTech Connect

The objectives of this work were to characterize the interactions of coal fly ash with polycyclic aromatic hydrocarbons (PAH`s) and their derivatives, and to attempt to understand the influence of surface properties of coal ash in the chemical transformations of PAH`s.

Mamantov, G.; Wehry, E.L.

1995-02-01

228

Biodegradation of sediment-bound PAHs in field-contaminated sediment  

Microsoft Academic Search

The biodegradation of polycyclic aromatic hydrocarbons (PAHs) has been reported to occur under aerobic, sulfate reducing, and denitrifying conditions. PAHs present in contaminated sites, however, are known for their persistence. Most published studies were conducted in systems where PAHs were freshly spiked, and biodegradation was often tested using pure cultures or enrichments. This paper investigated the degradation potentials of PAHs

L. Lei; A. P. Khodadoust; M. T. Suidan; H. H. Tabak

2005-01-01

229

Distribution of polycyclic aromatic hydrocarbons (PAHs) and sterols in termite nest, soil, and sediment from Great Kwa River, SE Nigeria.  

PubMed

Costal sediment samples from Great Kwa River as well as adjoining termite nest and soil samples were analyzed for quantitative determination of polycyclic aromatic hydrocarbons (PAHs) and sterols using gas chromatography-mass spectrometry (GC-MS) in order to access the possibility of transport of biologically produced PAHs/sterols from termite nest to the sediments. The total PAH concentrations (sum of parent and alkyl) for the sediments ranged between 131.96 and 139.35 ng/g dry weight (dw) while those for the nest and soil samples were in the range 9.51-9.71 and 71.85-77.26 ng/g dw, respectively. These levels of PAHs in sediments were relatively low compared to other urban/industrial Asian and American countries. No evidence of the usual biologically produced PAHs was found, thus reducing the likelihood of transport of these compounds from the nest to the sediments. The absence of parent and alkyl PAHs in central compartment of the nest may reflect the selective fern leaves feeding pattern of the dominant termite species prevalent in the vicinity of the study site. Utilization of six selected PAH ratios such as Fla/(Fla + Pyr) (0.4-0.5), Ant/(Ant + Phe) (0.25-0.90), BaA/(BaA + Chrys) (0.45-0.61), MP/P (0.05-6.81), 1,7/(1,7 + 2,6)-DMP (0.61-0.95), and LPAH/HPAH ( 2.80-3.80) allows discrimination of PAH sources for the samples to be made with a mixed source dominance observed. Examination of sterol distributions in the samples shows relatively high abundance of cholest-5-en-3?-ol in central compartment of the nest, considered here as a consequence of metabolic conversion of phyto-/fungi sterols in the tissues of the termite species. The relatively reduced levels of stanol compounds in central compartment of the nest may be associated with their utilization by the termites for growth and development. PMID:22544040

Oyo-Ita, Orok Esu; Oyo-Ita, Inyang Okon; Ugim, Samuel Ugim

2012-04-28

230

Diagnosis of PAH Properties and ISM Conditions based on the Near-Infrared and Mid-Infrared UIR Bands  

NASA Astrophysics Data System (ADS)

We report the results of near-infrared (NIR) to mid-infrared (MIR) slit spectroscopic observations of the diffuse emission from the Large Magellanic Cloud (LMC) with the Infrared Camera (IRC) on board AKARI. The present results suggest that the 3.3 ?m Unidentified Infrared (UIR) band provides powerful information on the size distribution and/or the excitation conditions of PAHs. A combination of the MIR bands with the 3.3 ?m band, such as the diagram of I3.3/I11.3 v.s. I7.7/I11.3, is shown to be a useful diagnostic tool for the radiation conditions of the PAH emitting regions.

Mori, T. I.; Sakon, I.; Onaka, T.; Kaneda, H.; Umehata, H.; Ohsawa, R.

2012-08-01

231

Emissions of polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs from heavy-duty diesel vehicles with DPF and SCR.  

PubMed

In total, 24 polycyclic aromatic hydrocarbons (PAHs) in both gas and particle phases and 35 nitro-PAHs in particle phase were analyzed in the exhaust from heavy-duty diesel vehicles equipped with after-treatment for particulate matter (PM) and NO(x) control. The test vehicles were carried out using a chassis dynamometer under highway cruise, transient Urban Dynamometer Driving Schedule (UDDS), and idle operation. The after-treatment efficiently abated more than 90% of the total PAHs. Indeed, the particle-bound PAHs were reduced by > 99%, and the gaseous PAHs were removed at various extents depending on the type of after-treatment and the test cycles. The PAHs in gas phase dominated the total PAH (gas + particle phases) emissions for all the test vehicles and for all cycles; that is, 99% of the two-ring and 98% of the three-ring and 97% of the four-ring and 95% of the carcinogenic PAHs were in the gas-phase after a diesel particle filter (DPF) and not bound to the very small amount of particulate matter left after a DPF. Consequently, an evaluation of the toxicity of DPF exhaust must include this volatile fraction and cannot be based on the particle fraction only. The selective catalytic reduction (SCR) did not appear to promote nitration of the PAHs in general, although there might be some selective nitration of phenanthrene. Importantly the after-treatment reduced the equivalent B[a]P (B[a]Peq) emissions by > 95%, suggesting a substantial health benefit. Implications: This study demonstrated that after-treatments, including diesel particulate filters (DPF), diesel oxidation catalysts (DOC), and selective catalytic reduction (SCR), significantly reduce the emissions of PAHs from heavy-duty diesel engines. The gas-phase PAHs dominate the total PAH (gas + particle phases) emissions from heavy-duty diesel vehicles retrofitted with various DPFs and not bound to the very small amount of particulate matter left after a DPF. Consequently, an evaluation of the toxicity of DPF exhaust must also include this volatile fraction and cannot be based on the particle fraction only. PMID:24010380

Hu, Shaohua; Herner, Jorn D; Robertson, William; Kobayashi, Reiko; Chang, M C Oliver; Huang, Shiou-Mei; Zielinska, Barbara; Kado, Norman; Collins, John F; Rieger, Paul; Huai, Tao; Ayala, Alberto

2013-08-01

232

Diagnostic interviews  

Microsoft Academic Search

This review addresses issues related to the use of structured psychiatric diagnostic interviews in children and adolescents.\\u000a Structured diagnostic interviews improve the diagnostic process by better organizing the collection of clinical data and eliminating\\u000a biases when applying diagnostic criteria. Available interviews generally fall into two categories. Highly structured (or respondent-based)\\u000a measures use a set script and record subject’s responses without

Ileana Calinoiu; Jon McClellan

2004-01-01

233

Adsorption and Degradation of PAH Compounds in Soil. Progress Report.  

National Technical Information Service (NTIS)

Organic contaminant fate in soil/water systems can be affected by the biological characteristics of the soil and of the pollutant. This work investigates biodegradation of polycyclic aromatic hydrocarbons (PAH) in a soil environment under denitrification ...

J. R. Mihelcic R. G. Luthy

1986-01-01

234

DISSIPATION OF PAHs IN SATURATED, DREDGED SEDIMENTS: A FIELD TRIAL  

Technology Transfer Automated Retrieval System (TEKTRAN)

Sediments dredged from navigable rivers often contain elevated concentrations of recalcitrant, potentially toxic organic compounds such as polychlorinated biphenyls (PCBs) and polyaromatic hydrocarbons (PAHs). The presence of these compounds often requires that the sediments be stored in fully conta...

235

POLYCYCLIC AROMATIC HYDROCARBON (PAH) EXPOSURE OF 257 PRESCHOOL CHILDREN  

EPA Science Inventory

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

236

Polycyclic aromatic hydrocarbons in Danish leafy crops. Part I: PAH in kale and beets relate to point sources of PAH. Part II: a survey of PAH in commercial grown fresh and deep-frozen kale  

SciTech Connect

Part I discusses the investigation of Polycyclic Aromatic Hydrocarbons (PAH) has been to demonstrate the possible pollution of leafy vegetables from expected PAH-emmissions, and to compare with similar investigations in Scandinavia. Part II is a survey has been to establish levels of PAH to which consumers are normally exposed from intake of fruits and above ground parts of vegetables.

Vahl, M.; Beck, J.; Stoebet, M.

1982-01-01

237

Biodegradation of PAHs and PCBs in Soils and Sludges  

Microsoft Academic Search

Results from a multi-year, pilot-scale land treatment project for PAHs and PCBs biodegradation are evaluated. A mathematical model, capable of describing sorption, sequestration, and biodegradation in a soil\\/water system, is applied to interpret the efficacy of a sequential active-passive biotreatment process of organic chemicals at remediation sites. To account for the recalcitrance of PAHs and PCBs in soils and sludges

L. Liu; J. A. Tindall; W. Zhang

2002-01-01

238

Biodegradation of a PAH Mixture by Native Subsurface Microbiota  

Microsoft Academic Search

Laboratory microcosm studies were conducted to estimate biodegradation rates for a mixture of five polycyclic aromatic hydrocarbon compounds (PAHs). Static microcosms were assembled using soil samples from two locations collected at a No. 2 fuel oil-contaminated site in the Atlantic Coastal Plain of Virginia. In microcosms from one location, five PAHs (acenaphthene, fluorene, phenanthrene, pyrene, and benzo(b)fluoranthene) biodegraded at net

J. Steven Brauner; Mark A. Widdowson; John T. Novak; Nancy G. Love

2002-01-01

239

Biodegradation of PAHs and PCBs in Soils and Sludges  

Microsoft Academic Search

Results from a multi-year, pilot-scale land treatment project for PAHs and PCBs biodegradation were evaluated. A mathematical\\u000a model, capable of describing sorption, sequestration, and biodegradation in soil\\/water systems, is applied to interpret the\\u000a efficacy of a sequential active–passive biotreatment process of organic chemicals on remediation sites. To account for the\\u000a recalcitrance of PAHs and PCBs in soils and sludges during

Ling Liu; James A. Tindall; Michael J. Friedel

2007-01-01

240

Polycyclic aromatic hydrocarbons (PAHs) in livers of California sea otters  

Microsoft Academic Search

Concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) were measured in livers of 81 adult female sea otters collected along the California coast in 1992–2002. Concentrations of ?PAHs in livers of sea otters were in the range of 588–17400ng\\/g lipid wt (mean: 3880ng\\/g, lipid wt). On a wet weight basis, the concentrations ranged from 17 to 1430ng\\/g (mean: 146ng\\/g). Overall, di-

Kurunthachalam Kannan; Emily Perrotta

2008-01-01

241

Diffuse PAH contamination of surface soils: environmental occurrence, bioavailability, and microbial degradation  

Microsoft Academic Search

The purpose of this review is to recognize the scientific and environmental importance of diffuse pollution with polycyclic\\u000a aromatic hydrocarbons (PAHs). Diffuse PAH pollution of surface soil is characterized by large area extents, low PAH concentrations,\\u000a and the lack of point sources. Urban and pristine topsoils receive a continuous input of pyrogenic PAHs, which induces a microbial\\u000a potential for PAH

Anders R. Johnsen; Ulrich Karlson

2007-01-01

242

THE EFFECTS OF EQUIVALENCE RATIO ON THE FORMATION OF POLYCYCLIC AROMATIC HYDROCARBONS AND SOOT IN PREMIXED ETHANE FLAMES. (R825412)  

EPA Science Inventory

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

243

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

Microsoft Academic Search

Food supplements can contain polycyclic aromatic hydrocarbons (PAH). The European Food Safety Authority (EFSA) has defined 16 priority PAH that are both genotoxic and carcinogenic and identified eight priority PAH (PAH8) or four of these (PAH4) as good indicators of the toxicity and occurrence of PAH in food. The current study aimed to determine benzo[a]pyrene and other EFSA priority PAH

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

2011-01-01

244

Polycyclic aromatic hydrocarbons (PAHs) in airborne particulate matter in Curitiba, Brazil and benzo(a)pyrene toxic equivalency factors (TEFs).  

PubMed

The concentration of PAHs in particulate matter was investigated in the city of Curitiba, located in south of Brazil. Urban atmospheric particulate matter was collected at six sampling sites whose characteristics were representative of the prevailing conditions. The concentration of particulate matter varied from 11.02 to 177.27 ng/m(3). Particulate matter was basically composed of PAHs with 3 and 4 aromatic rings and it agrees with results of air quality monitoring performed in other cities around the world. Molecular ratios, such as (Benzo(ghi)Perilene/Indene(cd)Pyrene, B(ghi)P/I(cd)P, indicate that the source of PAHs is gasoline engines in the downtown area and diesel engines in surrounding sites representing a heavy traffic situation. It was also investigated the toxic level of particulate matter using the BaP equivalency factor. The BaP(eq) for all samples was between 0.42 to 1.12 ng/m(3). The equivalency BaP(eq) indicated low health risk associated with exposure to the total PAHs content in environmental air. PMID:20658413

Froehner, Sandro; Maceno, Marcell; Machado, Karina Scurupa; Malheiros, Andre

2010-09-01

245

Formation and stability of hydrogenated PAHs in the gas phase  

NASA Astrophysics Data System (ADS)

Aims: We report on experimental and computational studies of hydrogenation of polycyclic aromatic hydrocarbon (PAH) cations, HnPAHs, which are relevant to the interstellar medium. Methods: The yield of the hydrogenated PAH cations produced in a plasma-ion source and by electrospray ionization was measured. DFT calculations at the B3LYP/6-311+G(d, p) and B3LYP/6-31+G(d, p) level of theory were performed to investigate the hydrogenation pattern. Results: A clear pattern in the yield and binding energies of hydrogen is revealed. Hydrogenated closed shell molecules with an even number of attached hydrogen atoms are significantly more stable than molecules with an odd number of hydrogen atoms and show as a consequence to be more abundant in mass spectra of HnPAHs. The binding energy of a hydrogen atom to Hn-1PAH with an even n is ~2 eV higher than for odd n. The exact distribution in n observed in the experimental mass spectra remains to be solved due to the unknown internal ion source conditions. Conclusions: The HnPAH cations have been produced under very different conditions, and the measured yield indicates high stability and likely high abundance in the interstellar medium.

Klærke, B.; Toker, Y.; Rahbek, D. B.; Hornekær, L.; Andersen, L. H.

2013-01-01

246

Artigo Original Determinação da eficiência do VEF 6 como substituto da CVF na triagem diagnóstica da doença pulmonar obstrutiva crônica através da comparação entre as relações VEF 1 \\/CVF e VEF 1 \\/VEF 6 * Determination of the efficacy of FEV 6 as a surrogate for FVC in the diagnostic screening for chronic obstructive pulmonary disease through the comparison of FEV 1 \\/FVC and FEV 1 \\/FEV 6 ratios  

Microsoft Academic Search

Objective: To determine the efficacy of using forced expiratory volume in six seconds (FEV 6 ) as a surrogate for forced vital capacity (FVC) in the diagnostic screening for chronic obstructive pulmonary disease (COPD) by comparing FEV 1 \\/FVC ratios with FEV 1 \\/FEV 6 ratios. Methods: In November of 2003, on World COPD Day, we conducted a campaign of

Marília Montenegro Cabral; Danielle Cristina; Silva Clímaco; Liana Gonçalves de Macedo; Marta de Andrade; Lima Coelho; Ana Lúcia; Pereira Lima; Alves Dias

2007-01-01

247

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

PubMed

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

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

2012-04-05

248

Polycyclic aromatic hydrocarbons (PAHs) in meat products and estimated PAH intake by children and the general population in Estonia.  

PubMed

The concentrations of benzo[a]pyrene and 11 other polycyclic aromatic hydrocarbons (PAHs) were analysed from 322 commercial, cured meat products and 14 home-grilled meat samples as part of the Estonian food safety monitoring programme during 2001-2005. The maximum acceptable concentration of 5 microg kg(-1) for benzo[a]pyrene was exceeded in 3.4% of samples. The highest PAH concentrations were detected in home-grilled pork samples. Using of disposable grilling unit resulted in 1.6 times higher PAH concentrations compared to the traditional wood-burning grill. The average intake of benzo[a]pyrene and sum of 12 PAHs from meat products was estimated for children (age 1-16 years) on the basis of an individual food consumption questionnaire and, for the general population, based on national food consumption data. The highest total PAH concentrations detected were 16 microg kg(-1) in smoked meat and ham, 19 microg kg(-1) in smoked sausage and 6.5 microg kg(-1) in smoked chicken samples. Since smoking and grilling are prevalent meat-cooking methods in Estonia, the impact of meat products is assessed to be significant in overall PAH intake. PMID:17454117

Reinik, M; Tamme, T; Roasto, M; Juhkam, K; Tenno, T; Kiis, A

2007-04-01

249

Influence of parasitism in controlling the health, reproduction and PAH body burden of petroleum seep mussels  

NASA Astrophysics Data System (ADS)

Petroleum seep mussels are often exposed to high hydrocarbon concentrations in their natural habitat and, thus, offer the opportunity to examine the relationship between parasitism, disease and contaminant exposure under natural conditions. This is the first report on the histopathology of cold-seep mussels. Seep mussels were collected by submersible from four primary sites in the Gulf of Mexico, lease blocks Green Canyon (GC) 184, GC-234, GC-233, and Garden Banks 425 in 550-650 m water depth. Five types of parasites were identified in section: (1) gill "rosettes" of unknown affinity associated with the gill bacteriocytes, (2) gill "inclusions" similar to chlamydia/rickettsia inclusions, (3) extracellular gill ciliates, (4) body "inclusions" that also resemble chlamydial/rickettsial inclusions, and (5) Bucephalus-like trematodes. Comparison to shallow-water mytilids demonstrates that: (1) both have similar parasite faunas; (2) seep mytilids are relatively heavily parasitized; and (3) infection intensities are extremely high in comparison to shallow-water mytilids for Bucephalus and chlamydia/rickettsia. In this study, the lowest prevalence for chlamydia/rickettsia was 67%. Prevalences of 100% were recorded from three populations. Bucephalus prevalence was ?70% in three of 10 populations. The parasite fauna was highly variable between populations. Some important parasites were not observed in some primary sites. Even within primary sites, some important parasites were not observed in some populations. Bucephalus may exert a significant influence on seep mussel population dynamics. Forty percent of the populations in this study are severely reproductively compromised by Bucephalus infection. Only a fraction of petroleum seep mussel populations are maintaining the entire beta-level population structure of this species. Variation in two parasites, gill ciliates and Bucephalus, explained most of the variation in PAH body burden between mussel populations. PAHs are known to be sequestered preferentially in gametic tissue. Bucephalus would be expected to reduce overall body burden, at high infection intensities, by replacing gametic tissue. PAH concentrations exceeded 1 ppm in 4 of 9 populations, a ratio significantly higher than the 8 of 30 mussel locales in the NOAA Mussel Watch Program. Only five Mussel Watch locales exceeded the highest value for a petroleum seep population. Digestive gland and gill tissue atrophy were not significantly correlated with PAH body burden, even though some populations were characterized by body burdens exceeding 1 ppm, suggesting that seep mussels may not be as sensitive to PAH exposure as are some shallow-water mytilid populations.

Powell, Eric N.; Barber, Robert D.; Kennicutt, Mahlon C., II; Ford, Susan E.

1999-12-01

250

Ozone pre-treatment as improver of PAH removal during anaerobic digestion of urban sludge.  

PubMed

Polycyclic aromatic hydrocarbons are ubiquitous persistent pollutants. They may accumulate in sludge during wastewater treatment because of their low biodegradability and their hydrophobic characteristics. Combination of ozonation and anaerobic digestion may be efficient to remove PAHs naturally present in sludge. The objective of this study was to investigate the impact of ozone pre-treatment, with and without surfactant addition, on the anaerobic degradation of 12 PAHs (from low to high molecular weight). Under anaerobic digestion without ozonation pre-treatment, the highest removals were obtained for the lightest PAHs (3-aromatic rings). Ozonation pre-treatment of sludge allowed to increase biodegradability or bioavailability of each PAH, and the PAH removals were well correlated to the PAH solubility. Finally, addition of tyloxapol before sludge ozone pre-treatment had antagonist effects on PAH removal during anaerobic digestion: negative impact on anaerobic ecosystem activity and improvement of PAH bioaccessibility (particularly the PAHs with the highest octanol water partition coefficients). PMID:17382369

Bernal-Martinez, Arodi; Carrère, Hélène; Patureau, Dominique; Delgenès, Jean-Philippe

2007-03-26

251

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

USGS Publications Warehouse

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

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

2009-01-01

252

Reproductive recovery of a common eider Somateria mollissima population following reductions in discharges of polycyclic aromatic hydrocarbons (PAHs).  

PubMed

Polycyclic aromatic hydrocarbons (PAHs) are widely distributed toxic compounds in marine ecosystems, but the effects of such pollutants on populations of aquatic birds are poorly known. This study examined the reproductive biology of a marine duck, the common eider (Somateria mollissima), in a Norwegian fjord that received high input of PAHs over several decades. Numbers of breeding females and post-hatch duckling mortality were compared between the years before and after termination of PAH discharges (1989/1990). Moreover, 5 years after the pollution was terminated, reproductive parameters were compared between the polluted fjord and a nearby unpolluted area, to investigate long-term effects. The environmental impact of the pollution peaked in the 1980s, and during this time the number of breeding eiders was halved in the study colony. The duckling mortality was very high, peaking in 1991 when about 8 % of all hatched ducklings were found dead in or near the nest. Since 1993 the ratio of dead ducklings per breeding female stabilized at about one third of the level before the termination of the PAH discharges. Moreover, between 1994 and 1999 the numbers of breeding females increased by 50 %, and in 1995 females in the polluted colony were in better condition, laid larger eggs and had shorter incubation periods than females in the unpolluted area. This study indicates that in the 1980s, PAH pollution affected the reproduction of the eiders in the polluted fjord, although other natural factors may also have influenced eider reproduction. A few years after the pollution level dropped, reproductive output improved strongly, but the number of ducklings dying in the nest was still relatively high compared to unpolluted areas. PMID:23797697

Bustnes, Jan O

2013-08-01

253

Occurrence of priority hazardous PAHs in water, suspended particulate matter, sediment and common eels (Anguilla anguilla) in the urban stretch of the River Tiber (Italy).  

PubMed

This study investigated the occurrence of polycyclic aromatic hydrocarbons (PAHs) in water, suspended particulate matter (SPM), bed sediment and common eels (Anguilla anguilla) in the urban stretch of the River Tiber (Italy). The selected PAHs, fluoranthene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, benzo(g,h,i)perylene, indeno(1,2,3-cd)pyrene, belong to the EC priority list of dangerous substances. SPM was found to be the most polluted compartment, with values ranging from 1663.1 to 15472.9 ngg(-1) (?(6)PAHs), followed by sediment samples, from 157.8 to 271.6 ngg(-1) and by aqueous samples, from 23.9 to 72.0 ngL(-1). The distribution coefficient (K(d)) showed a good correlation with particle organic carbon (OC) content, while K(oc) values experimentally measured for sediment/SPM deviated from those predicted by K(ow), implying that for very hydrophobic compounds, K(ow) alone may not be an appropriate descriptor of all the thermodynamic forces involved in their sorption to aquatic particles. Some selected PAH ratios indicated that PAHs in the River Tiber come mainly from pyrolitic sources and vehicular traffic. Concentrations of individual PAHs in muscles of common eels varied from 0.8 to 7.0 ngg(-1) wet wt. and the calculated toxicity equivalent concentration (TEQ, 1.8 ngg(-1) wet wt.) of total PAHs fell below the recommended screening value (SV) in US EPA guidelines, suggesting no concern for human consumption. PMID:20932548

Patrolecco, Luisa; Ademollo, Nicoletta; Capri, Silvio; Pagnotta, Romano; Polesello, Stefano

2010-10-06

254

Distribution of particle-phase hydrocarbons, PAHs and OCPs in Tianjin, China  

NASA Astrophysics Data System (ADS)

Aliphatic hydrocarbons, polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) were determined in the total suspended particles (TSP) collected from 13 different locations in Tianjin, China, where intensive coal burning for domestic heating in winter takes place and a large quantity of pesticides had been produced and applied. Carbon preference index (CPI), carbon number maximum (C max) of n-alkane and plant wax index (%wax C n) indicate that n-alkanes come from both biogenic and petrogenic sources, and biogenic source contributes more n-alkanes in autumn than in winter. Petroleum biomarkers as indicators of petrogenic source such as hopanes and steranes were also detected in both seasons' samples. The sum of 16 PAH concentrations (?PAH) ranged from 69.3 to 2170 ng m -3 in winter and from 7.01 to 40.0 ng m -3 in autumn. Seasonal variations were mainly attributed to the difference in coal combustion emission and meteorological conditions. The results of a source diagnostic analysis suggest that PAHs in TSP mainly come from coal combustion. Seven OCPs (four hexachlorohexanes (HCHs) and three dichlorodipheny-trichloroethane and metabolites (DDTs)) were detected in most samples. Concentrations of the sum of ?-, ?-, ?- and ?-HCH (?HCH) and the sum of p, p'-DDT, p, p'-DDD and p, p'-DDE (?DDT) in autumn varied in the ranges of 0.002-0.9 ng m -3 and 0.025-2.21 ng m -3 with the average±standard deviation values of 0.127±0.241 ng m -3 and 0.239±0.546 ng m -3, respectively. In winter, ?HCH and ?DDT in TSP ranged from 0.071 to 5.35 ng m -3 and from 0.416 to 3.14 ng m -3 with the average±standard deviation values 1.05±1.88 ng m -3 and 0.839±0.713 ng m -3, respectively. Both of the illegal application of technical HCH and DDT and the volatilization from topsoil contributed to the particle-phase contents of HCHs and DDTs in the atmosphere.

Wu, Shui-Ping; Tao, Shu; Zhang, Zhi-Huan; Lan, Tian; Zuo, Qian

255

Biodegradation of PAHs and PCBs in Soils and Sludges  

NASA Astrophysics Data System (ADS)

Results from a multi-year, pilot-scale land treatment project for PAHs and PCBs biodegradation are evaluated. A mathematical model, capable of describing sorption, sequestration, and biodegradation in a soil/water system, is applied to interpret the efficacy of a sequential active-passive biotreatment process of organic chemicals at remediation sites. To account for the recalcitrance of PAHs and PCBs in soils and sludges during long-term biotreatment, this model comprises a kinetic equation for organic chemical intraparticle sequestration. Model responses were validated by a favorable match to measurements of biodegradation of PAHs and PCBs in a land treatment unit operated by Aluminum Corporation of America Model simulations were performed to predict on-going biodegradation behavior of PAHs and PCBs in land treatment units. Simulation results indicate that complete biostabilization will be achieved when the concentration of reversibly sorbed chemical (SRA) reduces to zero (i.e., undetectable), with a certain amount of irreversibly sequestrated residual chemical (SIA) remaining within the soil particle solid phase. The residual fraction (SIA) tends to lose its original chemical and biological activity, and hence, is much less available, toxic, and mobile than the "free" compounds. Therefore, PAHs and PCBs will leach only slightly, if at all from the treatment site and thus, they constitute no threat to human health or the environment. Biotreatment of PAHs and PCBs can be terminated accordingly. Results from the pilot-scale testing data and model calculations also suggest that a significant fraction (10-30%) of high-molecular-weight PAHs and PCBs could be sequestrated and become unavailable for biodegradation. Bioavailability (large Kd, i.e., slow desorption rate) is the key factor limiting the PAHs degradation. However, both bioavailability and bioactivity, K (as described by Monod kinetics parameters), regulate PCBs biodegradation. The sequential active-passive biotreatment can be a cost-effective approach for remediation of highly hydrophobic organic contaminants. The mathematical model proposed here should be useful in the design and operation of such organic chemical biodegradation processes on remediation sites. Keywords: PAHs; PCBs; Biodegradation; land treatment; Mathematical model and application

Liu, L.; Tindall, J. A.; Zhang, W.

2002-12-01

256

Monitoring the occurrence of PAHs in Irish wastewater effluent.  

PubMed

Polycyclic aromatic hydrocarbons (PAHs) are commonly occurring environmental pollutants, 8 of which have been chosen from the list of priority substances in the EU Water Framework Directive (WFD). The levels of PAHs in the environment are affected by a number of emission factors including anthropogenic activities, population equivalents, and weather, all of which must be taken into account when monitoring levels of PAHs being released into the environment via waste water treatment plant effluent. Effluent samples have been collected from nine different wastewater treatment plants in 2 areas of Ireland (Dublin and Cork) over a period of 3 years (2009-2011), including several weeks of high intensity sampling. Solid phase extraction is used in the sample preparation process with subsequent analysis by gas chromatography with mass spectrometric detection (GCMS). All samples analysed contained the priority PAHs in this study; however levels detected do not exceed environmental quality standards (EQSs). Herein these results are related to a number of key emission factors affecting the levels of PAHs present in wastewater treatment plant effluent. This study aims to complement storm water studies and inform future targeted priority substance monitoring programmes. PMID:23034654

Jones, Lisa; Kinsella, Brian; Furey, Ambrose; Regan, Fiona

2012-11-01

257

Contamination of cachaça by PAHs from storage containers.  

PubMed

Cachaça is a distiled beverage obtained from the fermentation of sugar cane syrup that, depending on the production procedures, may be susceptible to contamination by polycyclic aromatic hydrocarbons (PAHs). These compounds present carcinogenic and/or mutagenic properties and offer a risk to human health. Sixteen PAHs were determined in cachaças that had been stored in glass bottles and in polyethylene tank by gas chromatography coupled with mass spectrometry. The quantification of the PAHs utilised an internal standard. The limits of detection and quantification varied from 0.05 to 0.10?gL(-)(1) and 0.20 to 0.30?gL(-)(1), respectively. A total PAH concentration of 51.57?gL(-)(1) was found in the beverages that were stored in the tank, while the concentration in the cachaça stored in glass jugs was 6.07?gL(-)(1). These results indicate that the polyethylene tank is a source for PAHs in cachaça. PMID:24176314

Machado, Ana Maria de R; Cardoso, Maria das Graças; Dórea, Haroldo S; Emídio, Elissandro S; Silva, Marcell M S; Dos Anjos, Jeancarlo P; Saczk, Adelir Aparecida; Nelson, David L

2013-09-11

258

PAH-CALUX, an Optimized Bioassay for AhR-Mediated Hazard Identification of Polycyclic Aromatic Hydrocarbons (PAHs) as Individual Compounds and in Complex Mixtures.  

PubMed

Polycyclic aromatic hydrocarbons (PAHs) represent a class of ubiquitously occurring environmental compounds that are implicated in a wide range of toxicological effects. Routine measurement of PAH contamination generally involves chemical analytical analysis of a selected group of representatives, for example, EPA-16, which may result in underestimation of the PAH-related toxicity of a sample. Many high molecular weight PAHs are known ligands of the aryl hydrocarbon receptor (AhR), a nuclear receptor that mediates toxic effects related to these compounds. Making use of this property we developed a PAH CALUX assay, a mammalian, H4IIe- cell-based reporter assay for the hazard identification of total PAH mixtures. The PAH CALUX reporter cell line allows for specific, rapid (4 h exposure time) and reliable quantification of AhR-induced luciferase induction relative to benzo[a]pyrene (BaP), which is used as a positive reference PAH congener. Full dose response relationships with inductions over 100-fold were reached within only 2 h of exposure to BaP. The PAH CALUX is highly sensitive, that is, using a 4 h exposure time, a limit of detection (LOD) of 5.2 × 10(-11) M BaP was achieved, and highly accurate, that is, a repeatability of 5.9% and a reproducibility of 6.6% were established. Screening of a selection of PAHs that were prioritized by the European Union and/or the U.S. Environmental Protection Agency showed that the PAH CALUX bioassay has a high predictability, particularly for carcinogenic PAHs. Experiments with synthetic mixtures and reference materials containing complex PAH mixtures show the suitability of the assay for these types of applications. Moreover, the presented results suggest that application of the PAH CALUX will result in a lower risk of underestimation of the toxicity of a sample than chemical analytical approaches that focus on a limited set of prioritized compounds. PMID:23987121

Pieterse, B; Felzel, E; Winter, R; van der Burg, B; Brouwer, A

2013-09-25

259

Diffuse interstellar bands and PAHs in the Galaxy and beyond  

NASA Astrophysics Data System (ADS)

Diffuse interstellar bands (DIBs) are ubiquitously observed towards reddened stars throughout the Milky Way. In the past decade, DIBs have been observed in only a few extra-galactic lines of sight. The carriers of DIBs are likely large organic gas phase molecules that reside in the diffuse interstellar medium. However, ever since they were first observed in the 1920s their identity remains a mystery. Investigated candidate carriers include, but are not limited to, carbon chains, polycyclic aromatic hydrocarbons (PAHs), fullerenes and tubular PAHs. Recent advances and successes in laboratory and theoretical work have given a great boost to the study of large molecules under interstellar conditions, i.e. low temperature, gas phase. We present here a short overview of our recent (extra)-galactic DIBs observations and the related studies of PAH chemistry in these environments.

Cox, Nick L. J.; Ehrenfreund, Pascale

2006-09-01

260

Relationships between aging of PAHs and soil properties.  

PubMed

Sequestration and diffusion of three polycyclic aromatic hydrocarbons (PAHs) in seven Chinese soils were investigated for up to 200 days in sterile soil microcosms as functions of soil property and aging time. The aging of the PAHs, assessed using a mild extractant that removes primarily the labile fraction, showed a biphasic behavior. The rapid diffusion from labile to nonlabile domains was mainly dependent upon the distribution of meso- and micropore fraction and total organic carbon content. Meanwhile, the slow diffusion was found to decrease with the increase of the content of soil organic carbon, particularly of hard organic carbon (p < 0.01) and the meso- and micropore fraction, as well as with the increasing molecular size of PAHs. This work offers evidence that analyses of organic carbon fractionation and porosity are important to adequately assess the mechanistic basis of sequestration and diffusion of organic contaminants in soils. PMID:22832330

Luo, Lei; Lin, Shu; Huang, Honglin; Zhang, Shuzhen

2012-07-24

261

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

SciTech Connect

Lung cancer caused by polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs and related environmental agents is a major problem in industrialized nations. The high case-fatality rate of the disease, even with the best supportive treatment, underscores the importance of primary lung cancer prevention. Development of biomarkers of exposure and effects to PAHs and related compounds is now underway and includes measurement of urinary metabolites of specific PAHs as well as detection of protein and DNA adducts as indicators of effective dose. Validation of these markers in terms of total environmental dose requires that concurrent measures of air levels and potential dermal exposure be made. In addition, the interrelationships between PAH biomarkers must be determined, particularly when levels of the marker in surrogate molecules (e.g., protein) or markers from surrogate tissues (e.g., lymphocyte DNA) are used to assess the risk to the target organ, the lung. Two approaches to biomarker studies will be reviewed in this article the progress made using blood lymphocytes as surrogates for lung tissues and the progress made developing noninvasive markers of carcinogen-DNA adduct levels in lung-derived cells available in bronchial-alveolar lavage and in sputum. Data are presented from studies in which exfoliated urothelial cells were used as a surrogate tissue to assess exposure to human urinary bladder carcinogens in occupational groups. 38 refs., 2 figs., 3 tabs.

Talaska, G.; Underwood, P.; Maier, A. [Univ. of Cincinnati Medical School, OH (United States)] [and others

1996-10-01

262

PAHs and PCBs deposited in surficial sediments along a rural to urban transect in a mid-Atlantic coastal river basin (USA).  

PubMed

PAHs and PCBs were measured in river sediments along a 226 km longitudinal transect that spanned rural to urban land use settings through Valley and Ridge, Piedmont Plateau and Coastal Plain physiographic provinces in the Potomac River basin (mid-Atlantic USA). A gradient in PAH concentrations was found in river bed sediments along the upstream transect in the Potomac and Shenandoah Rivers that correlated with population densities in the nearby sub-basins. Sediment PAH concentrations halved per each approximately 40 km of transect distance upstream (i.e., the half-concentration distance) from the urban center (Washington, DC) of the Potomac River basin in direct proportion to population density. The PAH molecular composition was consistent across all geologic provinces, revealing a dominant pyrogenic source. Fluoranthene to perylene ratios served as useful markers for urban inputs, with a ratio > 2.4 observed in sediments near urban structures such as roadways, bridges and sewer outfalls. PCBs in sediments were not well correlated with population densities along the river basin transect, but the highest concentrations were found in the urban Coastal Plain region near Washington, DC and in the Shenandoah River near a known industrial Superfund site. PAHs were moderately correlated with sediment total organic carbon (TOC) in the Shenandoah River and Coastal Plain Potomac River regions, but TOC was poorly correlated with PCB concentrations throughout the entire basin. Although both PAHs and PCBs are widely recognized as urban-derived contaminants, their concentration profiles and geochemistry in river sediments were uniquely different throughout the upper Potomac River basin. PMID:18780210

Foster, Gregory D; Cui, Vickie

2008-10-01

263

Biodegradation, bioaccessibility, and genotoxicity of diffuse polycyclic aromatic hydrocarbon (PAH) pollution at a motorway site.  

PubMed

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 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 14C-PAHs, and mutagenicity. Elevated PAH concentrations were found in the samples taken 1-8 m from the pavement. Soil sampled at greater distances (12-24 m) contained only background levels of PAHs. The total bacterial populations (CFU and numbers of 16S rDNA genes) were similar for all soil samples, whereas the microbial degrader populations (culturable PAH degraders and numbers of PAH dioxygenase genes) were most abundant 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 for lighter molecular weight PAH degradation in combination with low bioaccessibility of heavier PAHs is proposed to lead to a likely increase in concentration of heavier PAHs over time. These residues are, however, likely to be of low biological significance. PMID:16749696

Johnsen, Anders R; De Lipthay, Julia R; Reichenberg, Fredrik; Sørensen, Søren J; Andersen, Ole; Christensen, Peter; Binderup, Mona-lise; Jacobsen, Carsten S

2006-05-15

264

Phototransformation rate constants of PAHs associated with soot particles.  

PubMed

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. PMID:23247292

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

2012-12-17

265

Abundance, composition, and vertical transport of PAHs in marsh sediments.  

PubMed

Petroleum-derived hydrocarbons continue to persist in Wild Harbor, West Falmouth, MA, following a spill of No. 2 fuel oil in 1969 from the barge Florida. Recent analysis of marsh sediments revealed that residues of degraded oil are present with concentrations of total petroleum hydrocarbons as high as approximately 9 mg g(-1). Polycyclic aromatic hydrocarbons (PAHs) constitute only a minor fraction of these residues with maximum concentrations of 134 mirog g(-1), but their fate is of interest because of their potential toxicity to organisms. As compared to typical unweathered No. 2 fuel oil, the current distribution of PAHs in the sediments reflects substantial weathering by abiotic and biotic processes, specifically a preferential loss of naphthalenes relative to phenanthrenes, as well as isomer-specific biodegradation of alkylated PAHs. Based on comparison to results from an earlier study, it appears that little or no change has occurred to the distribution of PAHs since 1989, indicating that weathering at this site has stalled or is now proceeding at a significantly slower rate. To assess whether sediment-water partitioning and molecular diffusion in the interstitial medium are now the dominant processes controlling the vertical distribution of PAHs, downcore profiles were compared to a numerical model. While in some cases the model accurately reproduced the measured data, there were instances where the distribution of PAHs was slightly under or overestimated. Reasons for these discrepancies are discussed and are likely due to bioturbation, colloid-facilitated transport, or both. Assessment of the influence of these processes on the spilled oil expands our understanding of the overall fate of these compounds and their potential long-term effects on the environment. PMID:16294863

White, Helen K; Xu, Li; Lima, Ana Lúcia C; Eglinton, Timothy I; Reddy, Christopher M

2005-11-01

266

POLYCYCLIC AROMATIC HYDROCARBON AND EMISSION LINE RATIOS IN ACTIVE GALACTIC NUCLEI AND STARBURST GALAXIES  

SciTech Connect

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

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

2010-12-10

267

Polycyclic Aromatic Hydrocarbon and Emission Line Ratios in Active Galactic Nuclei and Starburst Galaxies  

NASA Astrophysics Data System (ADS)

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

Sales, Dinalva A.; Pastoriza, M. G.; Riffel, R.

2010-12-01

268

In prostatism patients the ratio of human glandular kallikrein to free PSA improves the discrimination between prostate cancer and benign hyperplasia within the diagnostic “gray zone” of total PSA 4 to 10 ng\\/mL  

Microsoft Academic Search

Objectives. Human glandular kallikrein (hK2) possesses approximately 80% structure identity with prostate-specific antigen (PSA). Moreover, messenger ribonucleic acid for hK2 and for PSA is expressed in both benign and malignant prostatic tissue. We investigated whether the hK2 serum measurement may improve the detection of prostate cancer (PCa) in patients with total PSA of 4 to 10 ng\\/mL (diagnostic “gray zone”).Methods.

Maciej K Kwiatkowski; Franz Recker; Timo Piironen; Kim Pettersson; Thomas Otto; Martin Wernli; Reto Tscholl

1998-01-01

269

Integrated analytical approach to detailed chemical characterization of coal liquefaction process materials. [Neutral PAH, cyano-PAH, hydroaromatics  

SciTech Connect

Due to the complexity and diversity of chemical species present in the products of coal liquefaction, methods that enable the class-specific separation and analytical determination of a wide concentration range of PAC constituents are of key importance in the detailed characterization of these complex materials. In this paper, an integrated analytical method for the quantitative and qualitative identification of the major chemical classes of coal conversion products has been reviewed. Specifically, techniques for the further elucidation of the neutral PAH, hydroaromatics, amino-PAH, and cyano-PAH have been presented. The end-goal in developing these methods is to provide a comprehensive data base of detailed information that can effectively assist the process engineer and biologist in establishing correlations between chemical composition and observed effects. 7 references, 11 figures, 1 table.

Later, D.W.; Chess, E.K.; Wright, C.W.; Wilson, B.W.

1984-11-01

270

A TOXICITY ASSESSMENT APPROACH FOR EVALUATION OF IN-SITU BIOREMEDIATION OF PAH CONTAMINATED SEDIMENTS  

EPA Science Inventory

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

271

SYNTHESIS AND BIOLOGICAL ACTIVITY OF NITRO-SUBSTITUTED CYCLOPENTA-FUSED PAH  

EPA Science Inventory

PAH containing a peripherally fused cyclopenta ring are genotoxically active in Salmonella and mammalian cells and have been identified in combustion emissions. Since the cyclopenta ring is predicted to be susceptible to electrophilic attack, nitrosubstituted cyclopenta-fused PAH...

272

PAH anions as carriers of the mid-IR emission bands in planetary nebulae  

NASA Astrophysics Data System (ADS)

We present results of the mid-IR spectra decomposition for planetary nebulae and compact H ii regions in our Galaxy and Magellanic Clouds. The striking correlation between the required PAH component with “7.7” ?m band shifted to about 7.8 ?m and electron densities of the modeled sources allows us to argue that this PAH component may be in fact PAH anions (PAH-).

Szczerba, Ryszard; Joblin, Christine; Berné, Olivier; Szyszka, Cezary

2008-10-01

273

Genome-to-function characterization of novel fungal P450 monooxygenases oxidizing polycyclic aromatic hydrocarbons (PAHs)  

PubMed Central

Fungi, particularly the white rot basidiomycetes, have an extraordinary capability to degrade and/or mineralize (to CO2) the recalcitrant fused-ring high molecular weight (? 4 aromatic-rings) polycyclic aromatic hydrocarbons (HMW PAHs). Despite over 30 years of research demonstrating involvement of P450 monooxygenation reactions in fungal metabolism of HMW PAHs, specific P450 monooxygenases responsible for oxidation of these compounds are not yet known. Here we report the first comprehensive identification and functional characterization of P450 monooxygenases capable of oxidizing different ring-size PAHs in the model white rot fungus Phanerochaete chrysosporium using a successful genome-to-function strategy. In a genome-wide P450 microarray screen, we identified six PAH-responsive P450 genes (Pc-pah1 - Pc-pah6) inducible by PAHs of varying ring size, namely naphthalene, phenanthrene, pyrene, and benzo(a)pyrene (BaP). Using a co-expression strategy, cDNAs of the six Pc-Pah P450s were cloned and expressed in Pichia pastoris in conjunction with the homologous P450 oxidoreductase (Pc-POR). Each of the six recombinant P450 monooxygenases showed PAH-oxidizing activity albeit with varying substrate specificity towards PAHs (3–5 rings). All six P450s oxidized pyrene (4-ring) into two monohydroxylated products. Pc-Pah1 and Pc-Pah3 oxidized BaP (5-ring) to 3-hydroxyBaP whereas Pc-Pah4 and Pc-Pah6 oxidized phenanthrene (3-ring) to 3-, 4-, and 9-phenanthrol. These PAH-oxidizing P450s (493 – 547 aa) are structurally diverse and novel considering their low overall homology (12–23%) to mammalian counterparts. To our knowledge, this is the first report on specific fungal P450 monooxygenases with catalytic activity toward environmentally persistent and highly toxic HMW PAHs.

Syed, Khajamohiddin; Doddapaneni, Harshavardhan; Subramanian, Venkataramanan; Lam, Ying Wai; Yadav, Jagjit S.

2010-01-01

274

Genome-to-function characterization of novel fungal P450 monooxygenases oxidizing polycyclic aromatic hydrocarbons (PAHs).  

PubMed

Fungi, particularly the white rot basidiomycetes, have an extraordinary capability to degrade and/or mineralize (to CO(2)) the recalcitrant fused-ring high molecular weight (4 aromatic-rings) polycyclic aromatic hydrocarbons (HMW PAHs). Despite over 30years of research demonstrating involvement of P450 monooxygenation reactions in fungal metabolism of HMW PAHs, specific P450 monooxygenases responsible for oxidation of these compounds are not yet known. Here we report the first comprehensive identification and functional characterization of P450 monooxygenases capable of oxidizing different ring-size PAHs in the model white rot fungus Phanerochaete chrysosporium using a successful genome-to-function strategy. In a genome-wide P450 microarray screen, we identified six PAH-responsive P450 genes (Pc-pah1-Pc-pah6) inducible by PAHs of varying ring size, namely naphthalene, phenanthrene, pyrene, and benzo(a)pyrene (BaP). Using a co-expression strategy, cDNAs of the six Pc-Pah P450s were cloned and expressed in Pichia pastoris in conjunction with the homologous P450 oxidoreductase (Pc-POR). Each of the six recombinant P450 monooxygenases showed PAH-oxidizing activity albeit with varying substrate specificity towards PAHs (3-5 rings). All six P450s oxidized pyrene (4-ring) into two monohydroxylated products. Pc-Pah1 and Pc-Pah3 oxidized BaP (5-ring) to 3-hydroxyBaP whereas Pc-Pah4 and Pc-Pah6 oxidized phenanthrene (3-ring) to 3-, 4-, and 9-phenanthrol. These PAH-oxidizing P450s (493-547 aa) are structurally diverse and novel considering their low overall homology (12-23%) to mammalian counterparts. To our knowledge, this is the first report on specific fungal P450 monooxygenases with catalytic activity toward environmentally persistent and highly toxic HMW PAHs. PMID:20674550

Syed, Khajamohiddin; Doddapaneni, Harshavardhan; Subramanian, Venkataramanan; Lam, Ying Wai; Yadav, Jagjit S

2010-07-30

275

Diagnostic laparoscopy  

MedlinePLUS

Laparoscopy - diagnostic ... of certain organs. If you are having gynecologic laparoscopy, dye may be injected into your cervix area ... You will probably not stay overnight after a laparoscopy. You will not be allowed to drive home. ...

276

Adsorption of polycyclic aromatic hydrocarbons (PAHs) by soil particles: influence on biodegradability and biotoxicity  

Microsoft Academic Search

Polycyclic aromatic hydrocarbon (PAH) biodegradation was investigated in contaminated soils from two different industrial sites under simulated land treatment conditions. Soil samples from a former impregnation plant (soil A) showed high degradation rates of PAHs by the autochthonous microorganisms, whereas PAHs in material of a closed-down coking plant (soil B) were not degraded even after inoculation with bacteria known to

Walter D. Weissenfels; Hans-Jiirgen Klewer; Joseph Langhoff

1992-01-01

277

BmPAH Catalyzes the Initial Melanin Biosynthetic Step in Bombyx mori  

PubMed Central

Pigmentation during insect development is a primal adaptive requirement. In the silkworm, melanin is the primary component of larval pigments. The rate limiting substrate in melanin synthesis is tyrosine, which is converted from phenylalanine by the rate-limiting enzyme phenylalanine hydroxylase (PAH). While the role of tyrosine, derived from phenylalanine, in the synthesis of fiber proteins has long been known, the role of PAH in melanin synthesis is still unknown in silkworm. To define the importance of PAH, we cloned the cDNA sequence of BmPAH and expressed its complete coding sequence using the Bac-to-Bac baculovirus expression system. Purified recombinant protein had high PAH activity, some tryptophan hydroxylase activity, but no tyrosine hydroxylase activity, which are typical properties of PAH in invertebrates. Because melanin synthesis is most robust during the embryonic stage and larval integument recoloring stage, we injected BmPAH dsRNA into silkworm eggs and observed that decreasing BmPAH mRNA reduced neonatal larval tyrosine and caused insect coloration to fail. In vitro cultures and injection of 4th instar larval integuments with PAH inhibitor revealed that PAH activity was essential for larval marking coloration. These data show that BmPAH is necessary for melanin synthesis and we propose that conversion of phenylalanine to tyrosine by PAH is the first step in the melanin biosynthetic pathway in the silkworm.

Chen, Ping; Li, Li; Wang, Jiying; Li, Haiyin; Li, Yan; Lv, Yin; Lu, Cheng

2013-01-01

278

Sediment-porewater partition of polycyclic aromatic hydrocarbons (PAHs) from Lanzhou Reach of Yellow River, China  

Microsoft Academic Search

Pollution of polycyclic aromatic hydrocarbons (PAHs) in the aquatic environment has drawn much attention around the world. The occurrence of 16 priority PAHs in the sediments and corresponding porewaters in Lanzhou Reach of Yellow River, China, and their partitioning behavior between the two phases were investigated. The results demonstrated that the total PAH levels in the sediments were positively correlated

Yong Yu; Jian Xu; Ping Wang; Hongwen Sun; Shugui Dai

2009-01-01

279

FAST ANALYSIS OF PAH BY GC AND GC\\/MS USING ISOMER SPECIFIC GC CAPILLARY COLUMNS  

Microsoft Academic Search

The required separation of polycyclic aromatic hydrocarbons (PAH) by GC, to meet regulatory requirements, depends largely on column selectivity. Liquid crystal (LC) capillary columns are highly selective for PAH separation. In the current investigation analysis and separation of PAH on columns coated with only the LC stationary phase, the combination of LC and non-polar stationary phase and only non-polar stationary

Allen J. Britten; Krishnat P. Naikwadi

2008-01-01

280

Single and Combined Effects of Sediment-Associated PAHs on Three Species of Freshwater Macroinvertebrates  

Microsoft Academic Search

Polycyclic Aromatic Hydrocarbons (PAHs) are ubiquitous pollutants of sediments. Sediment quality criteria often use toxicity data for individual PAHs. However, PAHs always occur in field sediments as a complex mixture of compounds. In this study, the toxicity of phenanthrene (P), fluoranthene (FLA) and benzo(k)fluoranthene (B), alone or in combination, was assessed using monospecific sediment tests of acute toxicity (between 24?h

G. Verrhiest; B. ClÉment; G. Blake

2001-01-01

281

Assessment of Factors Governing Biodegradability of PAHs in Three Soils Aged Under Field Conditions  

Microsoft Academic Search

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants of great environmental concern due to their toxic, mutagenic and carcinogenic properties. This study correlates soil characteristics (i.e. soil organic matter, particle- and pore-size distribution) with extractability and toxicity data (LUMIStox, Ostracod) to investigate factors that govern biodegradability of PAHs in three historically contaminated soils. Desorption of PAHs occurred most readily from soil

Hildegard Aichberger; Andreas P. Loibner; Rafael Celis; Rudolf Braun; Franz Ottner; Helmut Rost

2006-01-01

282

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

Microsoft Academic Search

It is commonly assumed that mass-transfer limitations are the cause for slow and incomplete biodegradation of PAHs in aged soils. In order to test this hypothesis, the biodegradation rate and the abiotic release rate were measured and compared for selected PAHs in three different soils. It was found that PAH biodegradation was not mass-transfer limited during slurry bioremediation of an

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

2000-01-01

283

Diffusion of PAH in potato and carrot slices and application for a potato model.  

PubMed

A method for quantifying the effect of medium composition on the diffusive mass transfer of hydrophobic organic chemicals through thin layers was applied to plant tissue. The method employs two silicone disks, one serving as source and one as sink for a series of PAHs diffusing through thin layers of water, potato tissue, and carrot tissue. Naphthalene, phenanthrene, anthracene, and fluoranthene served as model substances. Their transfer from source to sink disk was measured by HPLC to determine a velocity rate constant proportional to the diffusive conductivity. The diffusive flux through the plant tissue was modeled using Fick's first law of diffusion. Both the experimental results and the model suggest that mass transfer through plant tissue occurs predominantly through pore water and that, therefore, the mass transfer ratio between plant tissue and water is independent of the hydrophobicity of the chemical. The findings of this study provide a convenient method to estimate the diffusion of nonvolatile organic chemicals through various plant materials. The application to a radial diffusion model suggests that "growth dilution" rendersthe concentration of highly hydrophobic chemicals in potatoes below their equilibrium partitioning level. This is in agreement with field results for the bioconcentration of PAHs in potatoes. PMID:17539511

Trapp, Stefan; Cammarano, Anita; Capri, Ettore; Reichenberg, Fredrik; Mayer, Philipp

2007-05-01

284

Modeling Galactic extinction with dust and PAH (Mulas+, 2013)  

NASA Astrophysics Data System (ADS)

The model being used here includes two main components: a population of silicate core, carbon-coated dust grains, and a "molecular" component of free-flying PAHs. The descriptions of these components are detailed in section 2. (3 data files).

Mulas, G.; Zonca, A.; Casu, S.; Cecchi-Pestellini, C.

2013-08-01

285

Human Exposures to PAHs: an Eastern United States Pilot Study  

EPA Science Inventory

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

286

Understanding the Complexity and Strategic Evolution in PAH Remediation Research  

Microsoft Academic Search

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

Biswanath Mahanty; Kannan Pakshirajan; Veeranki Venkata Dasu

2011-01-01

287

The isotopic compositions of selected crude oil PAHs during biodegradation  

Microsoft Academic Search

Compound specific isotope analysis (CSIA) has been used to measure the ?13C of selected individual polycyclic aromatic hydrocarbons (PAHs) from a crude oil that was exposed to enhanced microbial biodegradation. Twenty-one liters of a crude oil were introduced to series of separate 5 m×5 m wetland plots along the San Jacinto River, Texas. Smaller grids were established within each area

Peter J. Yanik; Thomas H. O'Donnell; Stephen A. Macko; Yaorong Qian; Mahlon C. Kennicutt

2003-01-01

288

Effect of additives on biodegradation of PAH in soils  

Microsoft Academic Search

In a series of experiments with soil samples of contaminated sites we investigated the effect of special surfactant combinations and other additives on the kinetics and extent of solubilization and degradation of PAH. Biodegradation tests showed a positive effect of adding surfactant combinations T10 and T15. The effect was more pronounced when samples exhibited low degradation effectivity without surfactants. Addition

T Sobisch; H Heß; H Niebelschütz; U Schmidt

2000-01-01

289

MULTIMEDIA CONCENTRATIONS OF PAH IN SEVERAL DAY CARE CENTERS  

EPA Science Inventory

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

290

THE COMPUTED INFRARED SPECTRA OF A VARIETY OF [FePAH]{sup +} COMPLEXES: MID- AND FAR-INFRARED FEATURES  

SciTech Connect

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

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

2010-03-20

291

Plasma processing of interstellar PAHs into solar system kerogen  

NASA Astrophysics Data System (ADS)

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

Wdowiak, Thomas J.; Lee, Wei; Cronin, John; Beegle, Luther W.; Robinson, Michael S.

1995-02-01

292

Artificial-turf playing fields: Contents of metals, PAHs, PCBs, PCDDs and PCDFs, inhalation exposure to PAHs and related preliminary risk assessment  

Microsoft Academic Search

The artificial-turf granulates made from recycled rubber waste are of health concern due the possible exposure of users to dangerous substances present in the rubber, and especially to PAHs. In this work, we determined the contents of PAHs, metals, non-dioxin-like PCBs (NDL-PCBs), PCDDs and PCDFs in granulates, and PAH concentrations in air during the use of the field. The purposes

Edoardo Menichini; Vittorio Abate; Leonello Attias; Silvia De Luca; Alessandro di Domenico; Igor Fochi; Giovanni Forte; Nicola Iacovella; Anna Laura Iamiceli; Paolo Izzo; Franco Merli; Beatrice Bocca

2011-01-01

293

The role of CYP1A inhibition in the embryotoxic interactions between hypoxia and polycyclic aromatic hydrocarbons (PAHs) and PAH mixtures in zebrafish ( Danio rerio )  

Microsoft Academic Search

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants with elevated concentrations in waters that\\u000a may also experience hypoxia. Previous research has shown interactions between hypoxia and some PAHs (fluoranthene, ?-naphthoflavone)\\u000a but no interaction with others (benzo[a]pyrene (BaP), ?-naphthoflavone). Here we examine how hypoxia (7.4% oxygen, ~35% of\\u000a normoxia) affects the embryotoxicity of PAHs that act through different mechanisms and the

Carrie R. FlemingRichard; Richard T. Di Giulio

2011-01-01

294

Luminal transport step of para -aminohippurate (PAH): transport from PAH-loaded proximal tubular cells into the tubular lumen of the rat kidney in vivo  

Microsoft Academic Search

Proximal tubular cells were loaded for 10 s with [3H]para-aminohippurate ([3H]PAH) by microperfusing the peritubular capillaries with Ringer solution containing 0.05 mmol\\/l PAH. Immediately thereafter\\u000a [3H]PAH influx from cells into a column of equilibrium solution injected into the oil-filled tubular lumen was measured by re-aspirating\\u000a the fluid after 1–10 s of contact time. The rise of luminal PAH concentration within

K. J. Ullrich; Gerhard Rumrich

1997-01-01

295

Biomagnification profiles of polycyclic aromatic hydrocarbons, alkylphenols and polychlorinated biphenyls in Tokyo Bay elucidated by delta13C and delta15N isotope ratios as guides to trophic web structure.  

PubMed

Biomagnification profiles of polycyclic aromatic hydrocarbons (PAHs), alkylphenols, and polychlorinated biphenyls (PCBs) from the innermost part of Tokyo Bay, Japan were analyzed using stable carbon (delta(13)C) and nitrogen (delta(15)N) isotope ratios as guides to trophic web structure. delta(15)N analysis indicated that all species of mollusks tested were primary consumers, while decapods and fish were secondary consumers. Higher concentrations of PCBs occurred in decapods and fish than in mollusks. In contrast, concentrations of PAHs and alkylphenols were lower in decapods and fish than in mollusks. Unlike PCBs, whose concentrations largely increased with increasing delta(15)N (i.e. increasing trophic level), all PAHs and alkylphenols analyzed followed a reverse trend. Molecular weights of PAHs are lower than those of PCBs, therefore low membrane permeability caused by large molecular size is an unlikely factor in the "biodilution" of PAHs. Organisms at higher trophic levels may rapidly metabolize PAHs or they may assimilate less of them. PMID:19261300

Takeuchi, Ichiro; Miyoshi, Noriko; Mizukawa, Kaoruko; Takada, Hideshige; Ikemoto, Tokutaka; Omori, Koji; Tsuchiya, Kotaro

2009-03-03

296

Splicing of phenylalanine hydroxylase (PAH) exon 11 is vulnerable: molecular pathology of mutations in PAH exon 11.  

PubMed

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 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>C mutation resides in a putative splicing enhancer motif and binding by splicing factors SF2/ASF, SRp20 and SRp40 is disturbed. Additional mutations in potential splicing factor binding sites contributed to elucidate the pathogenesis of mutations in PAH exon 11. We suggest that PAH exon 11 is vulnerable due to a weak 3' splice site and that this makes exon 11 inclusion dependent on an ESE spanning position c.1144. Importantly, this implies that other mutations in exon 11 may affect splicing, since splicing is often determined by a fine balance between several positive and negative splicing regulatory elements distributed throughout the exon. Finally, we identified a pseudoexon in intron 11, which would have pathogenic consequences if activated by mutations or improved splicing conditions. Exonic mutations that disrupt splicing are unlikely to facilitate response to BH(4) and may lead to inconsistent genotype-phenotype correlations. Therefore, recognizing such mutations enhances our ability to predict the BH(4)-response. PMID:22698810

Heintz, Caroline; Dobrowolski, Steven F; Andersen, Henriette Skovgaard; Demirkol, Mübeccel; Blau, Nenad; Andresen, Brage Storstein

2012-05-29

297

Polycyclic aromatic hydrocarbon (PAH) source, sediment deposition patterns, and particle geochemistry as factors influencing PAH distribution coefficients in sediments of the Elizabeth River, VA, USA 1 Contribution No. 2221 from the Virginia Institute of Marine Science. 1  

Microsoft Academic Search

Sediments and pore waters from two sites in the urbanized Elizabeth River, Virginia were sampled for levels of polycyclic aromatic hydrocarbons (PAHs). Pore water PAH concentrations were similar between Sites 1 and 2, despite sediment PAH concentrations being much greater at Site 2. Organic carbon-normalized distribution coefficients (KOC)obs for all PAHs were significantly higher at Site 2 compared to Site

Siddhartha Mitra; Rebecca M. Dickhut; Steven A. Kuehl; Kimani L. Kimbrough

1999-01-01

298

The influence of Sarcocornia fruticosa on retention of PAHs in salt marsh sediments (Sado estuary, Portugal).  

PubMed

Depth concentration profiles of PAHs, organic carbon and dissolved oxygen in non-colonised sediments and sediments colonised by Sarcocornia fruticosa from Mitrena salt marsh (Sado, Portugal) were determined in November 2004 and April 2005. Belowground biomass and PAH levels in below and aboveground material were also determined. In both periods, colonised sediments were oxygenated until 15-cm, rich in organic carbon (max 4.4%) and presented much higher PAH concentrations (max. 7.1 microg g(-1)) than non-colonised sediments (max. 0.55 microg g(-1)). Rooting sediments contained the highest PAH concentrations. The five- and six-ring compounds accounted to 50-75% of the total PAHs in colonised sediments, while only to 30% in non-colonised sediments. The elevated concentrations of PAHs in colonised sediments may be attributed to the transfer of dissolved PAH compounds towards the roots as plant uptake water and subsequent sequestration onto organically rich particles. A phase-partitioning mechanism probably explains the higher retention of the heavier PAHs. In addition oxygenated conditions of the rooting sediments favour the degradation of the lighter PAHs and explain the elevated proportion of the heavier compounds. Below and aboveground materials presented lower PAH concentrations (0.18-0.38 microg g(-1)) than colonised sediments. Only 3- and 4-PAHs were quantified in aboveground material, reflecting either preferential translocation of lighter compounds from roots or atmospheric deposition. PMID:18068208

Martins, Marta; Ferreira, Ana Maria; Vale, Carlos

2007-12-18

299

Contamination of polycyclic aromatic hydrocarbons (PAHs) in microlayer and subsurface waters along Alexandria coast, Egypt.  

PubMed

The residues of seven polycyclic aromatic hydrocarbons (PAHs) pollutants in microlayer and subsurface seawater samples collected from Alexandria coast, Egypt, were analyzed by gas chromatography-electron-impact mass spectrometry-selected ion monitoring mode (GC-MS-SIM). The pollutants studied were, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, chrysene and benzo[a]pyrene. Total PAH levels in microlayer ranged from 103 to 523 ng/l, while it ranged in subsurface samples from 13 to 120 ng/l. The Western Harbor location recorded the highest level of PAHs pollutant over all the other location for both subsurface and microlayer waters. The two major PAHs in microlayer water at the Western Harbor were fluorene and phenanthrene, making up 27% and 20% of the total PAHs, while the two major PAHs in subsurface water at the Eastern Harbor were phenanthrene and fluoranthene recording up 21% each of the total PAHs. The total PAH levels were generally in the nano-gram per liter for microlayer and subsurface seawater samples. The dominant PAHs in both subsurface and microlayer samples were fluoranthene, pyrene and benzo[a]pyrene. The microlayer enrichment factor at Alexandria's Mediterranean coast was ranged from 29 for fluorene to 3 for phenanthrene and benzo[a]pyrene which showed PAHs concentration in the microlayer with an average of five times more than the total PAH in the subsurface samples. PMID:12871738

El Nemr, Ahmed; Abd-Allah, Aly M A

2003-09-01

300

Polycyclic aromatic hydrocarbon (PAH) exposure and DNA adduct semi-quantitation in archived human tissues.  

PubMed

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

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

2011-06-29

301

Polycyclic aromatic hydrocarbon (PAHs) pollutants in groundwater from coal gangue stack area: characteristics and origin.  

PubMed

The concentrations of polycyclic aromatic hydrocarbons (PAHs) in the leachate from the gangue and 20 groundwater samples, which were collected from the 12th Coal Mine around gangue piles in Henan Province, China, were determined by SPE-GC-MS. The characteristics of PAHs pollutants in groundwater were investigated, and compared with the concentrations of PAHs in the leachate from different weathered gangues to discuss the pollution effects of PAHs from coal gangue on groundwater. The results showed that total concentrations of the 16 EPA preferentially controlled PAHs ranged from 146.9 ng/L to 1220.6 ng/L.The components of PAHs such as chrysene, benzo[a]anthracene, benzo[b + k]fluoranthene, indeno[1,2,3-c,d]-pyrene, and dibenz[a,h]anthracene were fairly high. The 2-4 rings PAHs such as naphthalene, phenanthrene, fluorene and chrysene were dominant in groundwater, which was similar to those of the leachate from the different weathered gangues. Therefore, it should be paid much more attention on the transport of lower ring numbered PAHs leached by rains from the coal mines after landfilling and dumping. Based on the spatial distribution of PAHs and the high concentrations of PAHs with 2-4 rings in groundwater and leaching samples, there might be other pollution sources of PAHs except for penetration from coal gangue into groundwater in the Pingdingshan coal mine area. PMID:19273905

Wang, X W; Zhong, N N; Hu, D M; Liu, Z Z; Zhang, Z H

2009-01-01

302

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

SciTech Connect

Sewage sludge containing typical indigenous concentrations of polynuclear aromatic hydrocarbons (PAHs) was applied to several different soils in glass microcosms. Biologically active and sterilized soils were monitored for PAH content over a period of approximately 205 d. Agricultural soils with and without previous exposure to sewage sludge were tested, together with a forest soil and a soil from a major roadside. Loss of PAHs from a soil spike with a PAH standard solution was also investigated. Results indicate the PAH compounds with less than four benzene rings are susceptible to abiotic loss processes. However, losses by these mechanisms were insignificant for compounds with four or more benzene rings. Half-lives for the sludge-applied PAHs were derived and indicated a strong dependence of persistence on chemical structure. Half-lives for phenanthrene and benzo[ghi]perylene were between 83 and 193 d and 282 and 535 d, respectively. Mean half-lives correlate directly with log K[sub ow] and inversely with log water solubility. Behavior of PAHs was different in each soil, probably due to different soil characteristics and history of PAH exposure. The soil spiked with PAHs provided the lowest half-life values for most PAH compounds, suggesting a higher susceptibility of spiked PAHs to both abiotic and biological degradation.

Wild, S.R.; Jones, K.C. (Lancaster Univ. (United Kingdom))

1993-01-01

303

PAHs contamination in bank sediment of the Yamuna river, Delhi, India.  

PubMed

This study was performed to elucidate the distribution, concentration trend and possible sources of PAHs in bank sediment of river Yamuna in Delhi, India. The levels of 16 priority polycyclic aromatic hydrocarbons (PAHs) were analyzed during pre-monsoon, monsoon and post-monsoon seasons in the sediment fraction < 53 microm. Reference standards and internal standards were used for identification and quantification of PAHs by HPLC. The sum of 16 PAH compounds ranged from 4.50 to 23.53 microg/g with a mean concentration of 10.15 +/- 4.32 microg/g (dry wt.). Among 5 sites studied, the site, Income Tax Office (ITO) was found to be the hotspot attaining highest concentration. Predominance of 2-4 ring PAHs suggests a relatively recent local sources of PAHs in the study area. Moreover, molecular indices based source apportionment also illustrates pyrogenic source fingerprint of PAHs. No significant temporal trend was observed. PMID:16763739

Agarwal, Tripti; Khillare, P S; Shridhar, Vijay

2006-06-09

304

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

PubMed

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. PMID:18331771

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

2008-03-10

305

Behaviour of different lichen species as biomonitors of air pollution by PAHs in natural ecosystems.  

PubMed

Six different species of lichens (Parmelia sulcata Tayl., Evernia prunastri (L.) Ach., Ramalina farinacea, Pseudevernia furfuracea (L.) Zopf., Usnea sp. and Lobaria pulmonaria (Schreb.) Hoffm.) were collected in two mountain valleys in Central Pyrenees: the Aspe and Aragon valleys. Two multivariate techniques have been applied with different purposes, ANOVA and Discriminant Analysis (DA), to evaluate the data. The PAHs spatial distribution was studied in the three more abundant and widespread species in the area: P. sulcata, E. prunastri (L.) Ach. and R. farinacea in terms of total PAHs, PAHs related to the combustion processes and toxicity. Different behaviour of each lichen species to trap PAHs was found, being P. sulcata the best one to monitor the most persistent PAHs of pyrogenic origin and E. prunastri the most appropriate to provide information about pyrogenic and petrogenic PAHs. Traffic was the most relevant influence in PAHs bioaccumulation in lichen species. PMID:21822516

Blasco, María; Domeño, Celia; López, Patricia; Nerín, Cristina

2011-08-08

306

Phototoxicity and Environmental Transformation of Polycyclic Aromatic Hydrocarbons (PAHs)—Light-Induced Reactive Oxygen Species, Lipid Peroxidation, and DNA Damage  

Microsoft Academic Search

Polycyclic aromatic hydrocarbons (PAHs) are a class of mutagenic and tumorigenic environmental contaminants. Although the mechanisms by which PAHs induce cancer in experimental animals have been extensively studied and the metabolic activation pathways have been determined, the environmental fate of PAHs and the phototoxicity exerted by PAHs, as well as their photoreaction products formed in the environment, have received much

Peter P. Fu; Qingsu Xia; Xin Sun; Hongtao Yu

2012-01-01

307

Efficiency of defined strains and of soil consortia in the biodegradation of polycyclic aromatic hydrocarbon (PAH) mixtures  

Microsoft Academic Search

The microbiological characteristics of the bacterialdegradation of mixtures of five polycyclic aromatichydrocarbons (PAH), phenanthrene, fluorene,anthracene, fluoranthene and pyrene, wereinvestigated. Three pure bacterial strains using oneor several of these PAH as carbon sources wereselected. The interactions between PAH during thedegradation of PAH pairs by each of these strains werestudied and their effects on the kinetics and thebalance of degradation were characterised.

Murielle Bouchez; Denis Blanchet; Véronique Bardin; Frank Haeseler; Jean-Paul Vandecasteele

1999-01-01

308

Effect of non-aqueous phase liquid on biodegradation of PAHs in spilled oil on tidal flat  

Microsoft Academic Search

Biodegradation rates of polycyclic aromatic hydrocarbons (PAHs) in spilled oil stranded on tidal flats were evaluated using model reactors to clarify the effects of non-aqueous phase liquid (NAPL) on the biodegradation of PAHs in stranded oil on tidal flat with special emphasis on the relationship between dissolution rates of PAHs into water and viscosity of NAPL. Biodegradation of PAHs in

Tomohiro Kose; Tetsuo Mukai; Kazuto Takimoto; Mitsumasa Okada

2003-01-01

309

Reduction of Ferrrihydrite and Akaganeite by Shewanella alga (PAH93)  

Microsoft Academic Search

Shewanella species are capable of oxidizing diverse organic acids coupled to reducing Fe(III) (oxy)hydroxides to crystalline Fe(II)-containing phases such as magnetite, siderite, and vivianite. The objective of this study was to examine reduction of ferrihydrite and akaganeite as the electron acceptors using various organic acids as the electron donors by Shewanella alga (PAH93) isolated from Yeosu, South Korea. Microbial reduction

M. Jung; Y. Kim; Y. Lee; K. Kwon; Y. Roh

2009-01-01

310

Reduction of Ferrrihydrite and Akaganeite by Shewanella alga (PAH93)  

NASA Astrophysics Data System (ADS)

Shewanella species are capable of oxidizing diverse organic acids coupled to reducing Fe(III) (oxy)hydroxides to crystalline Fe(II)-containing phases such as magnetite, siderite, and vivianite. The objective of this study was to examine reduction of ferrihydrite and akaganeite as the electron acceptors using various organic acids as the electron donors by Shewanella alga (PAH93) isolated from Yeosu, South Korea. Microbial reduction of akaganeite (40 mM) and ferrihydrite (40 mM) was examined using acetate (10 mM), glucose (10 mM), and lactate (10 mM) as electron donors at room temperature. Ferrozine method was used to analyze both water soluble and HCl soluble Fe(II) concentrations during the microbial Fe(III) reduction. XRD and TEM-EDX analyses were used to characterize biominerals formed by PAH93. PAH93 was completely reduced ferrihydrite to Fe(II), which transformed as siderite (FeCO3). PAH93 was oxidized acetate, glucose, and lactate coupled to reducing akaganeite to magnetite or green rust. Microbial reduction of ferrihydrite resulted in higher soluble Fe(II) concentration (446 - 498 mg/L) than the reduction of akaganeite (255 - 284 mg/L) within 6 days of incubation. For 21 days of incubation, souble Fe(II) concentration during akaganeite reduction (945 - 1316 mg/L) was higher than ferrihydrite reduction (120 - 738 mg/L). It may be attributed to the differences of crystallinity of the iron minerals used for microbial iron reduction. This study indicates types of the electron acceptors, ferrihydrite and akaganeite, affect Fe(II) reduction rate and types of the biotransformed minerals.

Jung, M.; Kim, Y.; Lee, Y.; Kwon, K.; Roh, Y.

2009-12-01

311

Certification of Marine Sediment Reference Materials for PAHs  

Microsoft Academic Search

The Marine Analytical Chemistry Standards Program (MACSP) of the National Research Council of Canada produces certified reference materials for several analytes, including PAHs, in marine matrices. Four harbour sediment CRMs are available, HS-3,4,5, and 6. Stocks of HS-3 and 4 are depleted and require replacement. New sediment has been collected and processed. Design goals for the project included provision of

R. K. Boyd; S. M. Crain; J. M. Curtis; M. D. Leblanc; J. Macdonald; G. M. McCully; P. G. Sim; D. Thomas

1996-01-01

312

Butanol extraction to predict bioavailability of PAHs in soil  

Microsoft Academic Search

The feasibility of a mild-solvent extraction procedure to predict the bioavailability of individual polycyclic aromatic hydrocarbons (PAHs) in soil was assessed. The quantities that were degraded during the course of biodegradation of phenanthrene and pyrene in soil with or without plants correlated with the amounts extracted by n-butanol, with R2 values of 0.971 and 0.994, respectively. Six consecutive groups of

Hans-Holger Liste; Martin Alexander

2002-01-01

313

A PAH Deficit in Extremely Low Luminosity Galaxies  

NASA Astrophysics Data System (ADS)

Low levels of polycyclic hydrocarbon (PAH) emission in the spectra of dwarf galaxies has been a puzzle for the past 20 years. Here, we present the mid-infrared (MIR) properties of 27 extremely low luminosity dwarf galaxies (Mr>-15 mag) observed with the Spitzer Infrared Array Camera (IRAC). The dwarf galaxies studied in this work are randomly selected from the Sloan Digital Sky Survey (SDSS). They are nearby (z? 0.005) and are mostly isolated from more luminous galaxies. Using the magnitude at 7.8 micron as a tracer of PAH content and the magnitude at 3.6 micron as a tracer of stellar population, we compare the [7.8 micron]-[3.6 micron] color with metallicity based on oxygen and nitrogen lines, and o3, which is used as an indicator of radiation field hardness. We find that the PAH feature in the 7.8 micron band becomes weaker as the total galaxy luminosity becomes fainter. This is in agreement with earlier observations of dwarf galaxies, including a small sample taken by ISO, and the data taken from overlap of SDSS with the Spitzer First Look Survey. This work contains galaxies of mean absolute magnitudes about 3 mags fainter than any previouly studied sample of dwarf galaxies.

Wu, R.; Hogg, D. W.; Moustakas, J.

2009-01-01

314

Electronic Transitions of Protonated PAHs in 6 K Neon Matrices  

NASA Astrophysics Data System (ADS)

Protonated polycyclic aromatic hydrocarbons (H-PAH+s) are fundamental intermediates in organic chemistry and have been studied several decades ago in strong acidic solutions by NMR, IR and optical methods. Recently, they have been considered as possible carriers of certain diffuse interstellar bands (DIBs). According to TD-DFT calculations, such cations despite their closed-shell electronic structure could have strong transitions in the visible, where DIBs are detected. Diffuse interstellar absorption bands provide an unambiguous identification of interstellar molecules if their laboratory electronic spectra match astronomical observations. Therefore, the gas-phase spectroscopic measurements on H-PAH+s are necessary; they are limited currently to electronic spectra of protonated naphthalene and some larger protonated linear acenes. In the present contribution electronic absorption spectra of small H-PAH+s, anthracene, phenanthrene, pyrene and others, isolated in 6 K neon matrices are reported. The experimental setup is described. The cations of interest were produced in a hot-cathode discharge source, mass selected and codeposited with neon. The corresponding neutral species were produced in the same matrices by photobleaching the sample. The observed electronic transitions of the investigated species are compared to ab initio calculations, providing starting point for gas-phase measurements.

Garkusha, I.; Fulara, J.; Nagy, A.; Erattupuzha, S. M.; Maier, J. P.

2011-05-01

315

Alternative high-performance liquid chromatographic assay for p-aminohippuric acid (PAH): effect of aging on PAH excretion in the isolated perfused rat kidney  

Microsoft Academic Search

Para-aminohippuric acid (PAH), an indicator of renal plasma flow, is a commonly used marker of organic anion transport by the kidney. An analytical method for PAH using HPLC was developed. The method is simple, fast and requires a minimum amount of organic solvent. Sample preparation involved protein precipitation with zinc sulfate. Para-amino benzoic acid was utilized as an internal standard

Ishani A Savant; Michelle Kalis; Hassan Almoazen; Stephan R Ortiz; Malaz AbuTarif; David R Taft

2001-01-01

316

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

PubMed

A high-performance liquid chromatographic (HPLC) method with fluorescence detection was developed for the quantification of polycyclic aromatic hydrocarbons (PAHs) in human hair. Fifteen kinds of PAHs classified as priority pollutants by the US EPA were quantified with four perdeuterated PAHs as internal standards. After 50 mg hair samples were washed with n-hexane to remove external contamination of PAHs, the samples were digested in 2.5 M sodium hydroxide. The digests were extracted with n-hexane and then analyzed by HPLC. Eleven kinds of PAHs were identified in hair samples of 20 subjects, and 10 kinds of PAHs were eventually quantified using the internal standards. For anthracene, chrysene and benzo[k]fluoranthene, significant differences were observed between smokers and non-smokers. Although benzo[b]fluoranthene, dibenz[a,h]anthracene, benzo[ghi]perylene and indeno[1,2,3-cd]pyrene were observed in the particulates of indoor and outdoor air, they were not detected in all hair samples. The analysis of PAHs in human hair should be useful as a new biomarker to evaluate the exposure to PAHs. PMID:12717801

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

317

Laccase-carrying electrospun fibrous membranes for adsorption and degradation of PAHs in shoal soils.  

PubMed

The removal of polycyclic aromatic hydrocarbons (PAHs) from soil is costly and time-consuming. The high hydrophobicity of PAHs makes PAH diffusion from soil particles by hydraulic flow difficult. The phase transfer of PAHs from soil to another available mediator is crucial for PAH removal. This study focuses on the remediation of PAH-contaminated shoal soil, located in Yangtze, China, using three types of laccase-carrying electrospun fibrous membranes (LCEFMs) fabricated via emulsion electrospinning. These LCEFMs were composed of core-shell structural nanofibers (for PAH adsorption), with laccase in the core (for PAH degradation) and pores on the shell (for mass transfer). The LCEFMs with strong adsorptivity extracted the PAHs from the soil particles, resulting in an obvious enhancement of PAH degradation. The removal efficiencies in 6 h for phenanthrene, fluoranthene, benz[a]anthracene and benzo[a]pyrene were greater than 95.1%, 93.2%, 79.1%, and 72.5%, respectively. The removal half-lives were 0.003-1.52 h, much shorter than those by free laccase (17.9-67.9 h) or membrane adsorption (1.25-12.50 h). The third-order reaction kinetics suggested that the superficial adsorption and internal diffusion were the rate-limiting steps of the overall reaction. A synergistic effect between adsorption and degradation was also proposed on the basis of the triple phase distribution and kinetics analyses. PMID:22047140

Dai, Yunrong; Yin, Lifeng; Niu, Junfeng

2011-11-15

318

Evaluating sources of PAHs in urban streams based on land use and biomonitors.  

PubMed

Toxic polycyclic aromatic hydrocarbons (PAHs) can be found in wastewaters and sewages released from industries and/or urban areas. When discharged untreated to stream waters, they can be a problem to human health. This work represents the first attempt to use PAH and metal concentrations in aquatic moss transplants together with land-use information to identify water pollution sources in urban areas. To do this, the moss Fontinalis antipyretica was collected from a natural stream and transplanted to four different streams in a densely populated area of Lisbon, Portugal. After three months of exposure, mosses were collected and analyzed for metals and for the 16 priority PAHs recommended by the U.S. EPA. Urban streams seem to have a scattered contamination of 6-ring PAHs. Correlations among land-use, metal concentrations, and PAH concentrations indicated that areas occupied by activities of tertiary and industrial sectors had higher PAH concentrations in transplanted mosses, mainly for the sum of the 16 EPA-PAHs and for the 2-, 3- and 5-ringed PAHs, than areas occupied by urban and wooded areas. These PAHs were associated with enhanced Zn and Cu and land use activities that linked the sites to high traffic density. Industrial land use influences PAH concentration in water up to 1000 m of distance from the stream, whereas tertiary sector land use influences it up to 500 m. PMID:21410193

Augusto, Sofia; Gonzalez, Carla; Vieira, Rute; Máguas, Cristina; Branquinho, Cristina

2011-03-16

319

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

PubMed

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

Zhang, Zhenhua; Rengel, Zed; Meney, Kathy

2010-06-26

320

Environmental assessment of PAHs in soils around the Anhui Coal District, China.  

PubMed

Thirty-three soil samples were collected from the Luling, Liuer, and Zhangji coal mines, in the Huaibei and Huainan areas, Anhui Province, China, in 2007. The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs), identified as priority pollutants by the US Environmental Protection Agency (EPA), were determined by gas chromatography-mass spectrometry (GC-MS). The sum of 16 US EPA PAHs ranged from 0.13 to 3.54 microg/g (dry weight basis) with a mean concentration of 0.84 microg/g. Among the three sampling sites selected around the coal mines, the site at the Luling coal mine revealed maximum concentration of PAHs, whereas minimum concentration was observed at the site at the Zhangji coal mine. In general, low-molecular-weight PAHs were predominant. The gob pile and coal preparation plant are the sources of PAHs pollution in surface soils in the vicinity of coal mines. The crops in rice paddies might adsorb some PAHs and reduce the PAHs content in soils from paddy fields. The vertical distribution of PAHs in two soil profiles indicates that PAHs contamination in soil profiles tends to occur high in the surface soils and markedly decreases with soil depth. For all depths, PAHs showed a similar distribution pattern, which is an indicator of a similar origin. The total B[a]P equivalent concentration (B[a]Peq) was found to be maximum at the Luling area, whereas it was minimum at Liuer zones. PMID:20091163

Wang, Ruwei; Liu, Guijian; Chou, Chen-Lin; Liu, Jingjing; Zhang, Jiamei

2009-12-20

321

A step towards the use of biomonitors as estimators of atmospheric PAHs for regulatory purposes.  

PubMed

One of the main drawbacks of using lichens to monitor atmospheric PAHs has been reported as the inexistence of studies aiming to translate PAH values in lichens into the atmospheric equivalents ones, in order to use this information for regulatory purposes. In this work, PAH concentrations in lichens were compared with PAH concentrations measured in a conventional active sampler in an outdoor environment for a 9-month span. Significant positive correlations between HMW-PAHs, ?16 EPA-PAHs, and BaP equivalent concentrations in lichens and those in air (TSP) were found. Concentrations of ?16 EPA-PAHs in lichens and air showed a seasonal variation, with highest values during winter and lowest values during summer. Meteorological variables - temperature, atmospheric pressure, relative humidity, and wind speed - showed to significantly influence PAH concentrations in both lichens and air. Based on the significant linear correlations, equations for translating PAH concentrations measured in lichens into equivalent ones for air were proposed for the first time, allowing a broader use of lichens' information regarding PAHs in monitoring schemes and decision-making. PMID:23668962

Augusto, Sofia; Pereira, Maria J; Máguas, Cristina; Branquinho, Cristina

2013-05-10

322

Accumulation of weathered polycyclic aromatic hydrocarbons (PAHs) by plant and earthworm species.  

PubMed

Experiments were conducted to assess the bioavailability of polyclycic aromatic hydrocarbons (PAHs) in soil from a Manufactured Gas Plant site. Three plant species were cultivated for four consecutive growing cycles (28 days each) in soil contaminated with 36.3 microg/g total PAH. During the first growth period, Cucurbita pepo ssp. pepo (zucchini) tissues contained significantly greater quantities of PAHs than did Cucumis sativus (cucumber) and Cucurbita pepo ssp. ovifera (squash). During the first growth cycle, zucchini plants accumulated up to 5.47 times more total PAH than did the other plants, including up to three orders of magnitude greater levels of the six ring PAHs. Over growth cycles 2-4, PAH accumulation by zucchini decreased by 85%, whereas the uptake of the contaminants by cucumber and squash remained relatively constant. Over all four growth cycles, the removal of PAHs by zucchini was still twice that of the other species. Two earthworm species accumulated significantly different amounts of PAH from the soil; Eisenia foetida and Lumbricus terrestris contained 0.204 and 0.084 microg/g total PAH, respectively, but neither species accumulated measurable quantities 5 or 6 ring PAHs. Lastly, in abiotic desorption experiments with an aqueous phase of synthetically prepared organic acid solutions, the release of 3 and 4 ring PAHs from soil was unaffected by the treatments but the desorption of 5-6 ring constituents was increased by up to two orders of magnitude. The data show that not only is the accumulation of weathered PAHs species-specific but also that the bioavailability of individual PAH constituents is highly variable. PMID:16337258

Parrish, Zakia D; White, Jason C; Isleyen, Mehmet; Gent, Martin P N; Iannucci-Berger, William; Eitzer, Brian D; Kelsey, Jason W; Mattina, Maryjane Incorvia

2005-12-06

323

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

PubMed

Coal may become more important as an energy source in the 21st century, and coal contains large quantities of organic and inorganic matter. When coal burns chemical and physical changes take place, and many toxic compounds are formed and emitted. Polycyclic aromatic hydrocarbons (PAHs) are among those compounds formed and are considered to pose potential health hazards because some PAHs are known carcinogens. Based on their toxicology, 16 PAHs are considered as priority pollutants by the USEPA. More attention must be given to the various methods of extraction and analysis of PAH from coal or coal products to accurately explain and determine the species of PAHs. The influences of the extraction time, solvents, and methods for PAH identification are important. In the future, more methods and influences will be studied more carefully and widely. PAHs are environmental pollutants, are highly lipid soluble, and can be absorbed by the lungs, gut, and skin of mammals because they are associated with fine particles from coal combustion. More attention is being given to PAHs because of their carcinogenic and mutagenic action. We suggest that when using a coal stove indoors, a chimney should be used; the particles and gas containing PAHs should be released outdoors to reduce the health hazard, especially in Southwest China. During coal utilization processes, such as coal combustion and pyrolysis, PAHs released may be divided into two categories according to their formation pathways: one pathway is derived from complex chemical reactions and the other is from free PAHs transferred from the original coal. The formation and emission of PAHs is a complex physical and chemical process that has received considerable attention in recent years. It is suggested that the formation mechanisms of PAHs will be an increasingly important topic for researchers to find methods for controlling emissions during coal combustion. PMID:18020302

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

2008-01-01

324

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

PubMed

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

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

2010-12-03

325

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

PubMed

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

Luellen, Drew R; Shea, Damian

2003-11-01

326

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

PubMed

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

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

2006-10-10

327

Assessment of interactions between PAH exposure and genetic polymorphisms on PAH-DNA adducts in African American, Dominican, and Caucasian mothers and newborns.  

PubMed

Polycyclic aromatic hydrocarbons (PAH) are widespread pollutants commonly found in air, food, and drinking water. Benzo[a]pyrene is a well-studied representative PAH found in air from fossil fuel combustion and a transplacental carcinogen experimentally. PAHs bind covalently to DNA to form DNA adducts, an indicator of DNA damage, and an informative biomarker of potential cancer risk. Associations between PAH-DNA adduct levels and both cancer risk and developmental deficits have been seen in previous experimental and epidemiologic studies. Several genes have been shown to play an important role in the metabolic activation or detoxification of PAHs, including the cytochrome P450 genes CYP1A1 and CYP1B1 and the glutathione S-transferase (GST) genes GSTM1, and GSTT2. Genetic variation in these genes could influence susceptibility to adverse effects of PAHs in polluted air. Here, we have explored interactions between prenatal PAH exposure and 17 polymorphisms in these genes (rs2198843, rs1456432, rs4646903, rs4646421, rs2606345, rs7495708, rs2472299, rs162549, rs1056837, rs1056836, rs162560, rs10012, rs2617266, rs2719, rs1622002, rs140194, and gene deletion GSTM1-02) and haplotypes on PAH-DNA adducts in cord blood of 547 newborns and in maternal blood of 806 mothers from three different self-described ethnic groups: African Americans, Dominicans, and Caucasians. PAHs were measured by personal air monitoring of mothers during pregnancy. Significant interactions (p < 0.05) were observed between certain genetic polymorphisms and CYP1A1 haplotype and PAHs in mothers and their newborns in the three ethnic groups. However, with our limited sample size, the current findings are suggestive only, warranting further study. PMID:18268125

Wang, Shuang; Chanock, Stephen; Tang, Deliang; Li, Zhigang; Jedrychowski, Wieslaw; Perera, Frederica P

2008-02-01

328

Do the Infrared Emission Features Need UV Excitation? The PAH Model in UV-poor Reflection Nebulae  

NASA Astrophysics Data System (ADS)

One of the major challenges of identifying the 3.3, 6.2, 7.7, 8.6, and 11.3? m interstellar infrared emission bands with polycyclic aromatic hydrocarbon (PAH) molecules has been the recent detection of these bands in regions with little ultraviolet (UV) illumination since small, neutral PAH molecules have little or no absorption at visible wavelengths and thus are excited primarily by UV photons. The ``astronomical'' PAH model (Li & Draine 2001), incorporating the experimental result that the visual absorption edge shifts to longer wavelength upon ionization and/or as the PAH size increases (Allamandola, Hudgins, & Sandford 1999), is shown to be able to closely reproduce the observed infrared emission bands of vdB 133, a UV-poor reflection nebula (Uchida, Sellgren, & Werner 1998) as well as the 6.2, 7.7, and 11.3? m band ratios of the UV-deficient ring in the Andromeda galaxy M31 (Pagani et al. 1999). It is also shown that ``astronomical'' PAHs can be heated sufficiently by a T eff=3000 K black-body to emit at 6.2, 7.7, 8.6, and 11.3? m. Illustrative mid-IR emission spectra are calculated for reflection nebulae illuminated by cool stars with T eff=3600, 4500, 5000 K. These will allow comparison with future Space Infrared Telescope Facility (SIRTF) observations of vdB 135 (T eff=3600 K), vdB 47 (T eff=4500 K), and vdB 101 (T eff=5000 K) (Houck 2001). This research was supported in part by NASA grant NAG5-7030 and NSF grant AST-9619429. { References:} Allamandola, L.J., Hudgins, D.M., & Sandford, S.A. 1999, ApJ, 511, L115 Houck, J.R. 2001, SIRTF Observations of the Mid IR Features in Reflection Nebulae, {\\sf http://sirtf.caltech.edu/ROC/pid19} Li, A., & Draine, B.T. 2001, ApJ, 554, 778 Pagani, L., et al. 1999, A&A, 351, 447 Uchida, K.I., Sellgren, K., & Werner, M.W. 1998, ApJ, 493, L109

Li, A.; Draine, B. T.

2001-12-01

329

ATSDR evaluation of health effects of chemicals. IV. Polycyclic aromatic hydrocarbons (PAHs): understanding a complex problem.  

PubMed

Polycyclic Aromatic Hydrocarbons (PAHs) are a group of chemicals that are formed during the incomplete burning of coal, oil, gas, wood, garbage, or other organic substances, such as tobacco and charbroiled meat. There are more than 100 PAHs. PAHs generally occur as complex mixtures (for example, as part of products such as soot), not as single compounds. PAHs are found throughout the environment in the air, water, and soil. As part of its mandate, the Agency for Toxic Substances and Disease Registry (ATSDR) prepares toxicological profiles on hazardous chemicals, including PAHs (ATSDR, 1995), found at facilities on the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) National Priorities List (NPL) and which pose the most significant potential threat to human health, as determined by ATSDR and the Environmental Protection Agency (EPA). These profiles include information on health effects of chemicals from different routes and durations of exposure, their potential for exposure, regulations and advisories, and the adequacy of the existing database. Assessing the health effects of PAHs is a major challenge because environmental exposures to these chemicals are usually to complex mixtures of PAHs with other chemicals. The biological consequences of human exposure to mixtures of PAHs depend on the toxicity, carcinogenic and noncarcinogenic, of the individual components of the mixture, the types of interactions among them, and confounding factors that are not thoroughly understood. Also identified are components of exposure and health effects research needed on PAHs that will allow estimation of realistic human health risks posed by exposures to PAHs. The exposure assessment component of research should focus on (1) development of reliable analytical methods for the determination of bioavailable PAHs following ingestion, (2) estimation of bioavailable PAHs from environmental media, particularly the determination of particle-bound PAHs, (3) data on ambient levels of PAHs metabolites in tissues/fluids of control populations, and (4) the need for a critical evaluation of current levels of PAHs found in environmental media including data from hazardous waste sites. The health effects component should focus on obtaining information on (1) the health effects of mixtures of PAHs particularly their noncarcinogenic effects in humans, and (2) their toxicokinetics. This report provides excerpts from the toxicological profile of PAHs (ATSDR, 1995) that contains more detailed information. PMID:9050165

Mumtaz, M M; George, J D; Gold, K W; Cibulas, W; DeRosa, C T

330

Platinum ratio search versus golden ratio search  

Microsoft Academic Search

In this simulation study, we examine the traditional golden ratio search in view of cost minimization and search risk, and propose an alternative search plan with what we call “platinum ratio”. The golden ratio search has been thought the best for unimodal optimization. However, our study shows that the golden ratio search is the best only in the sense of

Xia Pan

2008-01-01

331

Spatial distribution and source apportionment of PAHs in surficial sediments of the Yangtze Estuary, China.  

PubMed

Spatial distribution and source apportionment of polycyclic aromatic hydrocarbons (PAHs) in the surface sediments of the Yangtze Estuary, especially the North Branch, have been fully investigated. PAH concentrations increased with the descending distance from the inner estuary to the adjacent sea, and varied significantly in various estuarine regions. Water currents (e.g., river runoff and ocean current) greatly affected the distribution pattern. In addition, ambient sewage and traffic also contributed to the PAH pollution in the estuary. In the adjacent sea, PAH values along the -20m isobath were higher than those along the -10m isobath due to the "marginal filter" phenomenon formed by different water currents. In most sites, PAHs had poor correlations with sediment size, but had positive correlations with total organic carbon. Based on the qualitative and quantitative analysis results, PAH sources were proved to be mainly from a mixture of petroleum combustion, biomass, and coal combustion. PMID:22245436

Li, Baohua; Feng, Chenghong; Li, Xue; Chen, Yaxin; Niu, Junfeng; Shen, Zhenyao

2012-01-14

332

Biomonitoring potentials of polycyclic aromatic hydrocarbons (PAHs) by higher plants from an oil exploration site, Nigeria.  

PubMed

Higher plants sampled from a moderately polluted exploration site were analyzed with gas chromatography-mass spectrometry to determine the occurrence and sources of polycyclic aromatic hydrocarbons (PAHs). The concentrations of the sum of 28 target PAHs (designated as ?(28)PAH) in the leaves of higher plant samples ranged from 365 to 2870 ?g/kg with an average of 1430 ?g/kg. The majority of the target compounds were detected except 9,10-diphenyl anthracene and dibenzo(a,h)anthracene, which were below the detection limits in most plant samples. In addition, the concentrations of the 2- and 3-ring PAHs, especially naphthalene and its alkylated derivatives, were generally higher than the 4-, 5- and 6-ring PAHs. Based on the results obtained in the present study, higher plants, especially non-woody annual and perennial plants could serve as good phytoremediators for a PAHs polluted sites. PMID:20869163

Sojinu, O Samuel; Sonibare, Oluwadayo O; Ekundayo, O; Zeng, Eddy Y

2010-09-24

333

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

PubMed

Motor vehicles are a significant source of airborne polycyclic aromatic hydrocarbons (PAH) in many urban areas. Traditional approaches used in determining the relative contributions of individual vehicle types to the total amount of PAH in air have been based on the analysis of integrated samples of airborne particles and gases for the presence of chemical tracers indicative of the vehicles from which the chemicals derived. As an alternative, we have used a photoelectric aerosol sensor (PAS) capable of measuring PAH levels in real-time in the emissions plumes from motor vehicles. We placed the PAS near a traffic-light in Kenmore Square, a busy crossroads in downtown Boston (MA, USA). A video camera co-located at the site recorded the vehicles passing the sensor, and this record was correlated with the PAS data. During a 5-day monitoring period (approximately 59 h) in the summer of 1998, over 34,000 motor vehicles were counted and classified and over 24,000 PAS readings were recorded (frequency = 1/8.6 s). The composition of the vehicle population was 94% passenger vehicles, 1.4% buses, 2.6% small trucks, 1.3% medium trucks, 0.35% large trucks, and 0.45% garbage and construction trucks. In analyzing the PAS data, it was assumed that the highest PAS measurements--those that exceeded the 95% critical level of the 5-min moving average of all the PAS measurements--were indicative of primary vehicular emissions. We found that approximately 46% of the mass of particle-bound PAH (i.e. approximately 46% of the integrated area under the PAS signal vs. time plots) was attributable to primary emissions from motor vehicles passing the sensor. Of this, 35-61% was attributable to passenger vehicles (cars, pickup trucks, and sports utility vehicles) and 39-65% was attributable to non-passenger vehicles [buses (14-23%), small trucks (12-20%), medium trucks (8.4-14%), large trucks (2.9-4.8%) and garbage and construction trucks (1.9-3.2%)]. Our results suggest that on a per vehicle basis, buses and trucks--the majority of which run on diesel fuel--emitted greater amounts of particle-bound PAH than passenger vehicles. Overall, we found that real-time photoelectric aerosol sensing (in combination with video photography) is useful for estimating the contributions of airborne PAB from different vehicle types. Due to the physical constraints of our monitoring site and the high volumes of traffic, however, it was not possible to uniquely attribute PAS signals to individual vehicles. PMID:11712588

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

2001-11-12

334

Fate of polycyclic aromatic hydrocarbons (PAH) in the rhizosphere and mycorrhizosphere of ryegrass  

Microsoft Academic Search

Polycyclic aromatic hydrocarbons (PAH) can be degraded in the rhizosphere but may also interact with vegetation by accumulation\\u000a in plant tissues or adsorption on root surface. Previous studies have shown that arbuscular mycorrhizal (AM) fungi contribute\\u000a to the establishment and maintenance of plants in a PAH contaminated soil. We investigated the fate of PAH in the rhizosphere\\u000a and mycorrhizosphere including

Ph. Binet; J. M. Portal; C. Leyval

2000-01-01

335

Particle Associated Polycyclic Aromatic Hydrocarbons (PAHS) in Urban Air of Agra  

Microsoft Academic Search

Total Suspended Particulate Matter (TSPM) samples were collected at Nunhai Agra from April to September 2006. The concentrations of 16 PAHs in aerosols were quantified. The dominated predominant PAHs in TSPM include high molecular weight (HMW) congeners BghiP, DbA, IP and BaP. Nap and Acy were not detected in any of the samples. The sum of 14 priority PAHs ranged

Nirat Rajput; Anita Lakhani

2012-01-01

336

Analytical methods for determining metabolites of polycyclic aromatic hydrocarbon (PAH) pollutants in fish bile: A review  

Microsoft Academic Search

The determination of polycyclic aromatic hydrocarbon (PAH) metabolites in bile can serve as a tool for assessing environmental PAH exposure in fish. Biliary PAH metabolite levels can be measured using several analytical methods, including simple fluorescence assays (fixed fluorescence detection or synchronous fluorescence spectrometry); high-performance liquid chromatography with fluorescence detection (HPLC-F); gas chromatography–mass spectrometry (GC–MS) after deconjugation, extraction and derivatization

Jonny Beyer; Grete Jonsson; Cinta Porte; Margaret M. Krahn; Freek Ariese

2010-01-01

337

Polycyclic Aromatic Hydrocarbons (PAHs) in Sediments of the White Sea, Russia  

Microsoft Academic Search

The extent of environmental contamination and sources of polycyclic aromatic hydrocarbon (PAH) compounds to sediments of the White Sea are evaluated and compared with previously published results for adjacent Arctic Sea areas. Concentrations of two- to six-ring PAHs of molecular mass 128–278 including perylene and sediment characteristics are considered in this investigation. Mean ?PAH concentration was 61±34 ng\\/g dw (n=11)

Vladimir M Savinov; Tatiana N Savinova; JoLynn Carroll; Gennady G Matishov; Salve Dahle; Kristoffer Næs

2000-01-01

338

The physico-chemical speciation of polycyclic aromatic hydrocarbons (PAH) in aquatic systems  

Microsoft Academic Search

\\u000a Zusammenfassung  Die „physikalisch-chemische Speziation“ wird dargestellt zur Beschreibung der Umweltchemie organischer Verbindungen in aquatischen\\u000a Systemen. Dabei dienen die PAH als Beispiel. Es werden Meßergebnisse und experimentelle Befunde gegeben, die die Anwesenheit\\u000a verschiedener physikalisch-chemischer Spezien von PAH in der Mündung des Tamar-Flusses (UK) demonstrieren. Es wird gezeigt,\\u000a daß der Grad und damit der Chemismus der Teilchenbindung von PAH im Tamarfluß nicht den

J. W. Readman; R. F. C. Mantoura; M. M. Rhead

1984-01-01

339

Polyaromatic hydrocarbon (PAH) distributions in the Seine River and its estuary  

Microsoft Academic Search

Dissolved and particulate PAHs were quantified throughout the Seine River and its estuary. Samples were collected in October 1993, covering a salinity gradient of 0.2‰ to 34.8‰. Two mooring stations were occupied at the river mouth to ascertain the influence of tidal cycles on the dispersal of riverborne PAHs. Total particulate PAH concentrations ranged from 2 to 687 ng l?1

M. B. Fernandes; M.-A. Sicre; A. Boireau; J. Tronczynski

1997-01-01

340

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

Microsoft Academic Search

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

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

2009-01-01

341

Seasonal Deposition Fluxes of Polycyclic Aromatic Hydrocarbons (PAHs) in Lake Biwa, Japan  

Microsoft Academic Search

Seasonal deposition fluxes of polycyclic aromatic hydrocarbons (PAHs) in the North Basin of Lake Biwa were investigated by\\u000a monthly collecting sediment trap samples through a year from July 2003. Average deposition flux of total PAHs was 75 ng cm?2 year?1, similar to those for other rural area. Deposition fluxes of PAHs did varied seasonally. In the vertical mixing period of\\u000a the

Shuji Tamamura; Tsutomu Sato; Yukie Ota; Yasuaki Aota; Kenji Kashiwaya; Michio Kumagai

2009-01-01

342

Polycyclic Aromatic Hydrocarbons (PAHs) in the Sediments of Beijiang River, China: Characteristics, Sources and Toxicity Evaluation  

Microsoft Academic Search

To estimate the status of polycyclic aromatic hydrocarbon (PAH) contamination in sediments of Beijiang River, 12 surface sediment samples were collected in January 2009 and analyzed for 16 PAHs listed as priority pollutants by US EPA using gas chromatography-mass spectrometry (GC-MS). The concentrations of PAHs in sediments were ranged from 44 to 8921 ng\\/g dry weight. The total concentrations of

Hui Zhang; Ping Huang; Mingwei Song

2011-01-01

343

Identification and Characterization of an Antigen I\\/II Homologous Gene, pah , from Streptococcus downei  

Microsoft Academic Search

Antigen I\\/II of Streptococcus mutans is a cell surface protein involved in the adherence of cells to tooth surfaces. In this study, an antigen I\\/II homologous\\u000a gene, pah, was identified and sequenced from Streptococcus downei MFe28 using degenerate polymerase chain reaction (PCR) and the gene-walking method. The pah gene encodes a cell-wall-anchoring protein, PAh, containing 1565 amino acids. At the

Haruki Tamura; Arisa Yamada; Hirohisa Kato

2008-01-01

344

Monitoring nutrient impact on bacterial community composition during bioremediation of anoxic PAH-contaminated sediment  

Microsoft Academic Search

Marine harbor sediments are frequently polluted with significant amount of polycyclic aromatic hydrocarbons (PAHs) some of\\u000a which are naturally toxic, recalcitrant, mutagenic, and carcinogenic. To stimulate biodegradation of PAHs in PAH-contaminated\\u000a sediments collected from near Gwangyang Bay, Korea, lactate was chosen as a supplementary carbonaceous substrate. Sediment\\u000a packed into 600 ml air-tight jar was either under no treatment condition or

Myungsu Kim; Seung Seob Bae; Mijin Seol; Jung-Hyun Lee; Young-Sook Oh

2008-01-01

345

Effect of Salinity on Biodegradation of Polycyclic Aromatic Hydrocarbons (PAHs) of Heavy Crude Oil in Soil  

Microsoft Academic Search

The spillage of crude oil in the soil damages the environment. Polycyclic aromatic hydrocarbons (PAHs) are one of the crude\\u000a oil components that may be harmful for living organisms. PAHs can disappear from the environment by volatilization and biodegradation.\\u000a The effect of different NaCl concentrations (0%–5%) on PAHs reduction from the heavy crude oil-contaminated soil was studied.\\u000a Our results showed

Dariush Minai-Tehrani; Saeed Minoui; Ali Herfatmanesh

2009-01-01

346

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

Microsoft Academic Search

Microbial consortia isolated from aged oil-contaminated soil were used to degrade 16 polycyclic aromatic hydrocarbons (15.72mgkg?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

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

2008-01-01

347

The NASA Ames PAH IR Spectroscopic Database: A Demo of its Contents and Web Tools  

NASA Astrophysics Data System (ADS)

The features formerly known as the Unidentified Infrared (UIR) Emission Bands are now generally attributed to polycyclic aromatic hydrocarbons (PAHs). Exploitation of these features as astrophysical and astrochemical probes requires the IR properties of PAHs under interstellar conditions. To fulfill this need, we experimentally measured and theoretically computed the 2-2000 µm spectra of many PAHs over the past 18 years at NASA's Ames Research Center. Today's collection comprises about 600 theoretically computed and 60 laboratory measured spectra of PAHs in different forms. The molecules in the collection range in size from C10H8 to C130H28. For most of these, spectra are available for PAHs in their neutral and singly charged (+/-) states. In some cases, IR spectra of multiply charged species were also computed. The database includes pure PAHs; PAHs containing nitrogen (PANHs), oxygen, and silicon; PAHs with side groups; PAHs with extra hydrogens; and PAHs complexed with iron and magnesium. This collection of PAH spectra from 2 - 2000 µm has been assembled into a uniform database, which we will make publicly available on the web in early 2009. A WebGUI interface has been developed that can effectively interrogate the database using a variety of queries, such as formula, molecular name, charge, specific number of atoms, etc. Several molecules can be selected in such a process and one can obtain their 3-D structures, plot and co-add their spectra, adjust parameters such as the bandwidth, download their data and print graphs. The database can also be downloaded as a whole and IDL-routines are provided to interrogate it. This talk will present an overview of the contents and the web-GUI tools of the NASA Ames PAH IR Spectroscopic Database. Hands-on demonstrations will be available at the SOFIA Booth.

Boersma, Christiaan; Sánchez de Armas, F.; Ricca, A.; Cami, J.; Peeters, E.; Mattioda, A. L.; Bauschlicher, C. W., Jr.; Allamandola, L. J.

2009-01-01

348

Oxidation of polycyclic aromatic hydrocarbons (PAH) by the white rot fungus, Phanerochaete chrysosporium  

Microsoft Academic Search

Key factors affecting the oxidation of polycyclic aromatic hydrocarbons (PAH) by the white rot fungus, Phanerochaete chrysosporium, including Mn2+ concentrations on extracellular enzyme production and PAH source were investigated. P. chrysosporium acted synergistically with soil indigenous microorganisms in the oxidation of low molecular weight PAH (i.e. acenaphthene, fluorene, phenanthrene, fluoranthene and pyrene) in a soil-slurry, where oxidation was enhanced by

Zhongming Zheng; Jeffrey Philip Obbard

2002-01-01

349

Bioassay-directed fractionation of PAH of molecular mass 302 in coal tar-contaminated sediment  

Microsoft Academic Search

Bioassay-directed fractionation was used to characterise genotoxic polycyclic aromatic hydrocarbons (PAH) of molecular mass 302 amu in organic solvent extracts of coal tar-contaminated sediment from Sydney Harbour, Nova Scotia. A normal phase HPLC technique was employed to separate PAH-rich solvent extracts into fractions containing PAH of single molecular mass classes. The 302 amu molecular mass fraction was isolated and further

C. H. Marvin; B. E. McCarry; J. A. Lundrigan; K. Roberts; D. W. Bryant

1999-01-01

350

Distribution and transport of coal tar-derived PAHs in fine-grained residuum  

Microsoft Academic Search

We investigated the distribution and transport of coal tar-derived polycyclic aromatic hydrocarbons (PAHs) in fine-grained residuum and alluvial floodplain deposits that underlie a former manufactured gas plant. All 16 USEPA priority pollutant PAHs are present at this site and have penetrated the entire 4–5m thickness of clayey sediments, which unconformably overly limestone bedrock. Concentrations of less hydrophobic PAHs (e.g., naphthalene,

Vijay M. Vulava; Larry D. McKay; Steven G. Driese; Fu-Min Menn; Gary S. Sayler

2007-01-01

351

Urate transport via human PAH transporter hOAT1 and its gene structure  

Microsoft Academic Search

Urate transport via human PAH transporter hOAT1 and its gene structure.BackgroundWe recently cloned the human organic anion transporter 1 (hOAT1) as a p-aminohippurate (PAH) transporter. Whether urate is transported by the PAH transporter in humans remains unclear. Familial juvenile gouty nephropathy (FJGN) is thought to develop as a result of an abnormality in the urate transporter.MethodsTo determine if hOAT1 transported

Kimiyoshi Ichida; Makoto Hosoyamada; Hiroaki Kimura; Michio Takeda; Yasunori Utsunomiya; Tatsuo Hosoya; Hitoshi Endou

2003-01-01

352

Assessing PAH and PCB emissions from the relocation of harbour sediments using equilibrium passive samplers.  

PubMed

Large-scale dredging of contaminated sediments is taking place in the harbor of Oslo, Norway. The dredged sediment masses are transferred into a confined aquatic disposal facility (CAD) in a natural 70-m deep basin within the Oslofjord. Currently there is no established method to determine how much dissolved contaminants are released during relocation and deposition of these sediments. For this reason we tested the use of equilibrium passive samplers consisting of 55 microm thin polyoxymethylene (POM-55) for studying the release of freely dissolved and thus bioavailable PAHs and PCBs at the disposal site, and found this to be a suitable method. In order to use POM-55 for monitoring PCBs, it was necessary to measure their POM-55/water partition coefficients, which was also presented as part of this study. Elevated turbidity (average 4.1 mg l(-1)) was observed at one side of the basin where no natural sill exists. Analysis of POM-55 at this location before and after deposition revealed that there was an increase in freely dissolved concentrations (C(W,free)) during deposition by a factor 37.5 for PAHs and a factor of 2.9 for PCBs. In addition, during deposition phenanthrene-to-anthracene aqueous concentration ratios at this location (values of 3-4) were more similar to those of the deposited sediments (approximately 2) than to those of the CAD water prior to deposition (approximately 14). This was not observed for the other locations where a natural sill exists at approximately 30 m water depth. The POM-55 equilibrium passive samplers are here shown to be useful tools for measuring and understanding the dynamics involved in the release of dissolved contaminants during sediment relocation. PMID:18514764

Cornelissen, Gerard; Arp, Hans Peter H; Pettersen, Arne; Hauge, Audun; Breedveld, Gijs D

2008-06-02

353

Enhanced NIF neutron activation diagnostics  

SciTech Connect

The NIF neutron activation diagnostic suite relies on removable activation samples, leading to operational inefficiencies and a fundamental lower limit on the half-life of the activated product that can be observed. A neutron diagnostic system measuring activation of permanently installed samples could remove these limitations and significantly enhance overall neutron diagnostic capabilities. The physics and engineering aspects of two proposed systems are considered: one measuring the {sup 89}Zr/{sup 89m}Zr isomer ratio in the existing Zr activation medium and the other using potassium zirconate as the activation medium. Both proposed systems could improve the signal-to-noise ratio of the current system by at least a factor of 5 and would allow independent measurement of fusion core velocity and fuel areal density.

Yeamans, C. B.; Bleuel, D. L.; Bernstein, L. A. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

2012-10-15

354

Estimation of PAHs dry deposition and BaP toxic equivalency factors (TEFs) study at Urban, Industry Park and rural sampling sites in central Taiwan, Taichung  

Microsoft Academic Search

The concentrations of polycyclic aromatic hydrocarbons (PAHs) in gas phase and particle bound were measured simultaneously at industrial (INDUSTRY), urban (URBAN), and rural areas (RURAL) in Taichung, Taiwan. And the PAH concentrations, size distributions, estimated PAHs dry deposition fluxes and health risk study of PAHs in the ambient air of central Taiwan were discussed in this study. Total PAH concentrations

Guor-Cheng Fang; Kuan-Foo Chang; Chungsying Lu; Hsunling Bai

2004-01-01

355

NSTX Diagnostics and Operation: Status and Plans  

SciTech Connect

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

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

2001-08-30

356

Diurnal/nocturnal concentrations and sources of particulate-bound PAHs, OPAHs and NPAHs at traffic and suburban sites in the region of Paris (France).  

PubMed

Particulate concentrations of polycyclic aromatic compounds (PACs) including, 17 polycyclic aromatic hydrocarbons (PAHs), 9 oxygenated PAHs (OPAHs) and 18 nitrated PAHs (NPAHs) were determined at traffic and suburban sites located in the region of Paris. A 12 h sampling basis time resolution was applied in order to study their diurnal and nocturnal variations. Observed concentrations were about 10 times higher at the traffic site for all compounds and were higher during the night-time for both sites (except for NPAHs at the traffic site). No significant differences in PAH and OPAH profiles were observed at both sites whereas, for NPAHs, 1-nitropyrene (diesel source) was the most abundant at the traffic site and 2+3-nitrofluoranthene (secondary formed by gas-phase reaction) was predominant at the suburban site. The study of the specific ratio 2-nitrofluoranthene/1-nitropyrene (2-NFlt/1-NP) showed a local formation of NPAHs in gaseous phase at the suburban site. A detailed analysis showed that atmospheric humidity and rainfalls modified differently PAH and NPAH profiles, in comparison to OPAH. A difference of the scale variability of water solubility between, light (MW?228 g mol(-1)) and heavy compounds (MW?273 g mol(-1)), could explain these observations. The specific study of the relationships between PACs and other measured pollutants highlighted that particle resuspension could constitute a significant source of PM on the traffic site. Even if NPAH formation seemed clearly evident at the suburban site during periods characterised by high O(3) and NO(2) concentration levels, results showed also that the primary and/or secondary origins of OPAHs and NPAHs were strongly dependent on the sampling site and on sampling conditions. Finally, we conclude that higher time sampling resolutions would be helpful in investigating the atmospheric chemistry and behaviours of PACs in correlation with the local meteorological variations and the daily cycle of human activities. PMID:22947617

Ringuet, Johany; Albinet, Alexandre; Leoz-Garziandia, Eva; Budzinski, Hélène; Villenave, Eric

2012-09-01

357

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

PubMed

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

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

2004-06-01

358

Sorption and chemical transformation of PAHs on coal fly ash. Technical progress report No. 6  

SciTech Connect

The objective of this work is to characterize the interactions of coal fly ash with polycyclic aromatic hydrocarbons (PAHs) and their derivatives, and to understand the influence of the surface properties of coal ash (and other atmospheric particles) on the chemical transformations of polycyclic aromatic compounds. Specific investigations directed toward this overall objective include: (a) Fractionation of heterogeneous coal fly ash samples into different particle types varying in size and chemical composition (carbonaceous, mineralmagnetic, and mineral nonmagnetic); (b) Measurement of the rates of chemical transformation of PAHs and PAH derivatives (especially nitro-PAHs) and the manner in which the rates of such processes are influenced by the chemical and physical properties of coal fly ash particles; (c) Chromatographic and spectroscopic studies of the nature of the interactions of coal fly ash particles with PAHs and PAH derivatives; (d) Characterization of the fractal nature of fly ash particles (via surface area measurements) and the relationships of ``surface roughness`` of fly ash particles to the chemical behavior of PAHs sorbed on coal ash particles. PAHs are deposited, under controlled laboratory conditions, onto coal ash surfaces from the vapor phase, in order to mimic the processes by which PAHs are deposited onto particulate matter in the atmosphere.

Mamantov, G.; Wehry, E.L.

1993-06-01

359

Sorption and chemical transformation of PAHs on coal fly ash. Technical progress report No. 8  

SciTech Connect

The objective of this work is to characterize the interactions of coal fly ash with polycyclic aromatic hydrocarbons (PAHs) and their derivatives, and to understand the influence of the surface properties of coal ash (and other atmospheric particles) on the chemical transformations of polycyclic aromatic compounds. Specific investigations directed toward this overall objective include: (a) Fractionation of heterogeneous coal fly ash samples into different particle types varying in size and chemical composition (carbonaceous, mineral-magnetic, and mineral nonmagnetic); (b) Measurement of the rates of chemical transformation of PAHs and PAH derivatives (especially nitro-PAHs) and the manner in which the rates of such processes are influenced by the chemical and physical properties of coal fly ash particles; (c) Chromatographic and spectroscopic studies of the nature of the interactions of coal fly ash particles with PAHs and PAH derivatives; (d) Characterization of the fractal nature of fly ash particles (via surface area measurements) and the relationships of {open_quotes}surface roughness{close_quotes} of fly ash particles to the chemical behavior of PAHs sorbed on coal ash particles. PAHs are deposited, under controlled laboratory conditions, onto coal ash surfaces from the vapor phase, in order to mimic the processes by which PAHs are deposited onto particulate matter in the atmosphere.

Mamantov, G.; Wehry, E.L.

1993-12-01

360

Concentrations and possible sources of PAHs in sediments from Bohai Bay and adjacent shelf  

Microsoft Academic Search

Concentrations, spatial distribution and sources of 16 polycyclic aromatic hydrocarbons (PAHs) listed by the United States\\u000a Environmental Protection Agency as priority pollutants were investigated in surface sediments of Bohai Bay, North China. Total\\u000a concentrations of PAHs were in the range of 140.6–300.7 ng\\/g (dry wt), with an average of 188.0 ng\\/g. The three predominant\\u000a PAHs were phenanthrene, acenaphthene and naphthalene. Sedimentary PAH

Ningjing Hu; Xuefa Shi; Jihua Liu; Peng Huang; Yanguang Liu; Ying Liu

2010-01-01

361

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

PubMed

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

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

2008-02-13

362

Polycyclic aromatic hydrocarbons (PAHs) in surface sediments of Liaodong Bay, Bohai Sea, China  

Microsoft Academic Search

Materials and methods  The levels and possible sources of 16 polycyclic aromatic hydrocarbons (PAHs) were investigated in the surface sediments of\\u000a Liaodong Bay, Bohai Sea, China.\\u000a \\u000a \\u000a \\u000a \\u000a Results  The sum of 16 PAHs (?PAH16) concentrations varied from 144.5 to 291.7 ng\\/g, with a mean value of 184.7 ng\\/g, indicating low PAH levels compared with\\u000a reported values for other bays and rivers in China and developed

Ningjing Hu; Xuefa Shi; Peng Huang; Jian Mao; Jihua Liu; Ying Liu; Deyi Ma

2011-01-01

363

Polyaromatic hydrocarbons (PAHs) and metal evaluation after a diesel spill in Oaxaca, Mexico.  

PubMed

Pollution in the marine environment due to a diesel spill takes days to months to complete natural remediation owing to its low volatility. Metal and PAH contamination caused by an accidental diesel spill were studied. V, Ni and Hg levels increased immediately after the spill, while PAH levels decreased after 1 month (79.4-7.6 microg kg(-1)). At the diesel spill point, fluoranthene exceeded acute and chronic levels, although most of the PAHs were within the range of low effects. In fish body burden, the highest bioaccumulation factor (2.63 for naphthalene) was related to the lower molecular weight PAHs. PMID:17712506

Salazar-Coria, L; Amezcua-Allieri, M A; Tenorio-Torres, M; González-Macías, C

2007-08-22

364

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

SciTech Connect

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

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

2008-07-01

365

PM2.5-bound PAHs and hydroxy-PAHs in atmospheric aerosol samples: Correlations with season and with physical and chemical factors  

NASA Astrophysics Data System (ADS)

Over a one-year period, the concentrations of ten polycyclic aromatic hydrocarbons (PAHs) and two of their hydroxy derivatives (OH-PAHs) were monitored in a suburb of Madrid (Spain). The levels of other chemical indicators of urban pollution (nitrogen oxides, sulphur oxides, etc.), as well as a series of meteorological variables (temperature, atmospheric pressure, etc.) were determined simultaneously. PAH concentrations varied according to the environmental conditions such that depending on the wind direction and speed, levels exceeded those expected for outside the central city area. Concentrations of 2-hydroxyphenanthrene ranged from 12 to 200 pg m-3 and those of 1-hydroxypyrene from 3 to 60 pg m-3. Their variations were directly related to levels of phenanthrene and pyrene and also found to depend on the weather conditions, especially temperature and atmospheric pressure. Through multivariate analysis (factor and cluster analyses) a clear link was detected between the concentrations of PAHs or hydroxy-PAHs and those of other chemical pollutants (nitrogen and sulphur oxides). We also observed an inverse relationship with temperature, ozone concentration, solar radiation and UV radiation intensity. Changes in both PAHs and OH-PAHs were clearly seasonal, increasing in the colder months and undergoing a reduction in the warmer months of the year.

Barrado, Ana Isabel; García, Susana; Barrado, Enrique; Pérez, Rosa María

2012-03-01

366

Responses of Human Cells to PAH-Induced DNA Damage  

Microsoft Academic Search

Benzo[ a ]pyrene (B[ a ]P) and dibenzo[ a,l ]pyrene (DB[ a,l ]P) induce cytochrome P450 (CYP) CYP1A1 and CYP1B1, which metabolize these polycyclic aromatic hydrocarbons (PAHs) into DNA-binding species. In order to detail roles of CYP1A1 and CYP1B1 in activation of DB[ a,l ]P to the diol epoxide, we here report the inhibition of CYP1A1 in human MCF-7 cells

William M. Baird; Louisa A. Hooven; Brinda Mahadevan; Andreas Luch; Albrecht Seidel; Patrick L. Iversen

2002-01-01

367

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

PubMed Central

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

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

1998-01-01

368

Determination of octanol-air partition coefficients and supercooled liquid vapor pressures of PAHs as a function of temperature: Application to gas-particle partitioning in an urban atmosphere  

NASA Astrophysics Data System (ADS)

Octanol-air partition coefficients ( KOA) for 14 polycyclic aromatic hydrocarbons (PAHs) were determined as a function of temperature using the gas chromatographic retention time method. log KOA values at 25° ranged over six orders of magnitude, between 6.34 (acenaphthylene) and 12.59 (dibenz[ a,h]anthracene). The determined KOA values were within factor of 0.7 (dibenz[ a,h]anthracene) to 15.1 (benz[ a]anthracene) of values calculated as the ratio of octanol-water partition coefficient to dimensionless Henry's law constant. Supercooled liquid vapor pressures ( PL) of 13 PAHs were also determined using the gas chromatographic retention time technique. Activity coefficients in octanol calculated using KOA and PL ranged between 3.2 and 6.2 indicating near-ideal solution behavior. Atmospheric concentrations measured in this study in Izmir, Turkey were used to investigate the partitioning of PAHs between particle and gas-phases. Experimental gas-particle partition coefficients ( Kp) were compared to the predictions of KOA absorption and KSA (soot-air partition coefficient) models. Octanol-based absorptive partitioning model predicted lower partition coefficients especially for relatively volatile PAHs. Ratios of measured/modeled partition coefficients ranged between 1.1 and 15.5 (4.5±6.0, average±SD) for KOA model. KSA model predictions were relatively better and measured to modeled ratios ranged between 0.6 and 5.6 (2.3±2.7, average±SD).

Odabasi, Mustafa; Cetin, Eylem; Sofuoglu, Aysun

369

An evaluation of polycyclic aromatic hydrocarbon (PAH) runoff from highways into estuarine wetlands of South Carolina.  

PubMed

This study investigated the concentrations and potential toxicity of polycyclic aromatic hydrocarbons (PAHs) associated with highway runoff into adjacent estuarine wetlands from road segments representing three levels of average daily traffic (ADT): low (<5,000 ADT), moderate (10,000-15,000 ADT), and high use (>25,000 ADT) based on SC Department of Transportation data. Sediments from three estuarine wetland habitats (tidal creeks, Spartina marsh, and mud flats) adjacent to these road segments were sampled to represent nine highway use class/habitat type combinations. Surficial sediments were collected at 3, 25, and 50 meters from the upland/wetland interface along transects established perpendicular to the road at each site, with additional samples taken from the road berm. Average PAH concentrations, representing 25 compounds, ranged from 3.9 to 11,000 ng/g dry weight. Berm samples had significantly greater total PAH concentrations than samples taken in any of the wetland habitats. Average total PAH concentrations decreased with increasing distance from the road berm within the wetland habitats sampled, but the differences were not statistically significant. Average total PAH concentrations also were not significantly different among the wetland habitats compared. Analysis of PAH profiles indicated that the PAH source was dominated by pyrogenic combustion products rather than from petrogenic sources. This, combined with the presence of dibenzothio-phene, which is a tire oxidation product, indicated that the primary source of PAHs was related to vehicles. Two sites with total PAH concentrations exceeding published bioeffects levels were resampled for bioassay tests using the amphipod Ampelisca verrilli, the polychaete Streblospio benedicti, and the clam, Mercenaria mercenaria, with the first two assays conducted under UV lighting since previous studies had demonstrated enhanced UV toxicity of PAHs for these species. No toxicity was observed in the amphipod or polychaete assays. Toxicity was observed in the juvenile clam assay at one site, possibly due to the combined effects of PAHs and other contaminants present. PMID:16132419

Van Dolah, R F; Riekerk, G H M; Levisen, M V; Scott, G I; Fulton, M H; Bearden, D; Sivertsen, S; Chung, K W; Sanger, D M

2005-08-12

370

Effect of Substrate Character on Heterogeneous Ozone Reaction Rate with Individual PAHs and Their Reaction Mixtures  

NASA Astrophysics Data System (ADS)

Vehicle exhaust contains many unregulated chemical compounds that are harmful to human health and the natural environment, including polycyclic aromatic hydrocarbons (PAH), a class of organic compounds derived from fuel combustion that can be carcinogenic and mutagenic. PAHs have been quantified in vehicle-derived ultrafine particles (Dp<100nm), which are more toxic than larger particles and are linked to adverse health problems, including respiratory and cardiac disease. Once emitted into the atmosphere, particle-bound PAHs can undergo “aging” reactions with oxidants, such as ozone, to form more polar species. These polar reaction products include species such as quinones that can be more toxic than the parent PAH compounds. Here, 0.4ppm ozone was reacted over a 24-hour period with the 16 EPA priority PAHs plus coronene adsorbed to (i) a quartz fiber filter and (ii) NIST diesel PM. The difference in the PAH/O3 heterogeneous reaction rate resulting from the two substrates will be discussed. The experiments were completed by spiking a known PAH mixture to the solid, reacting the samples with gas-phase ozone, and determining both PAH loss over time and products formed, using thermal-desorption gas chromatography / mass spectrometry (TD-GC/MS). The individual PAHs anthracene, phenanthrene, and fluorene, adsorbed to a QFF were also separately reacted with 0.4 ppm ozone. A volatilization control and the collection of volatilized PAHs using a Tenax-packed thermal desorption vial completed the mass balance and aided determination parent-product relationships. Heterogeneous reaction products analyzed directly without derivatization indicate the formation of 9,10-anthracenedione, 9H-fluoren-9-one, and (1,1’-biphenyl)-2,2’-dicarboxaldehyde from the reaction of ozone with the PAH mix on a QFF, but only 9,10-anthracenedione was detected for the diesel PM reaction. The implications of these results for aging of diesel particulate in urban environments will be discussed.

Holmen, B. A.; Stevens, T.

2009-12-01

371

Gas/particle Partitioning and Particle Size Distributions of Polycyclic Aromatic Hydrocarbons (pahs) in the Atmosphere.  

NASA Astrophysics Data System (ADS)

This study applied three different gas/particle (G/P) separation mechanisms (diffusion, filtration and impaction) to investigate G/P partitioning and particle size distributions of polycyclic aromatic hydrocarbons (PAHs) in the atmosphere. Because some PAHs such as benzo (a) pyrene have been shown to be carcinogenic to humans and persistent in the environment, it is important to have reliable methods to measure PAH G/P partitioning and particle size distributions for the purpose of understanding their atmospheric processing and their impact to environmental and human health. The objectives of this study include: (1) Development of a diffusion separator (DS) to separate a known fraction of the gas phase from the aerosol: The calibration experiment results reveal that the G/P separation performance of the DS agrees well with diffusion theory. True gas PAH concentrations are calculated by the measured PAH concentrations in the core exit of the DS and the diffusion factor at the sampling temperature. (2) Evaluation of sampling artifacts associated with high volume samplers and their effectiveness in measuring PAH G/P partitioning in the atmosphere: The comparison between the DS, a filter/adsorbent sampler (FA) and a microorifice uniform deposit impactor (MOUDI) revealed both gaseous sorption onto filters and desorption from filters of the FA sampler for most PAHs. (3) Investigation of particle size distribution of PAHs in Chicago urban and Minnesota suburban areas: The results of MOUDI sampler showed that the PAH mass median diameters (MMDs) are smaller than atmospheric particle MMDs by 0.1-0.3 ?m in both areas. The calculated PAH dry deposition fluxes and Lake Michigan sediment accumulation rates indicates that the atmospheric dry deposition contributes 15-50% of PAHs to nearby Lake Michigan sediment.

Liu, Shi-Ping

372

Application of magnetite-activated persulfate oxidation for the degradation of PAHs in contaminated soils.  

PubMed

In this study, feasibility of magnetite-activated persulfate oxidation (AP) was evaluated for the degradation of polycyclic aromatic hydrocarbons (PAHs) in batch slurry system. Persulfate oxidation activated with soluble Fe(II) (FP) or without activation (SP) was also tested. Kinetic oxidation of PAHs was tracked in spiked sand and in aged PAH contaminated soils at circumneutral pH. Quartz sand was spiked with: (i) single model pollutant (fluorenone) and (ii) organic extract isolated from two PAH contaminated soils (H and NM sampled from ancient coking plants) and was subjected to oxidation. Oxidation was also performed on real H and NM soils with and without an extraction pretreatment. Results indicate that oxidation of fluorenone resulted in its complete degradation by AP while abatement was very low (<20%) by SP or FP. In soil extracts spiked on sand, significant degradation of 16 PAHs was observed by AP (70-80%) in 1 week as compared to only 15% by SP or FP systems. But no PAH abatement was observed in real soils whatever the treatment used (AP, FP or SP). Then soils were subjected to an extraction pretreatment but without isolation of organic extract from soil. Oxidation of this pretreated soil showed significant abatement of PAHs by AP. On the other hand, very low degradation was achieved by FP or SP. Selective degradation of PAHs was observed by AP with lower degradation efficiency towards high molecular weight PAHs. Analyses revealed that no by-products were formed during oxidation. The results of this study demonstrate that magnetite can activate persulfate at circumneutral pH for an effective degradation of PAHs in soils. However, availability of PAHs and soil matrix were found to be the most critical factors for degradation efficiency. PMID:22273186

Usman, M; Faure, P; Ruby, C; Hanna, K

2012-01-23

373

UV action spectroscopy of protonated PAH derivatives. Methyl substituted quinolines  

NASA Astrophysics Data System (ADS)

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 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 are explained by TD-DFT calculations. The dissociation time of the studied molecules is found to be of several milliseconds at 230 nm and it is shown that after redistribution of the absorbed energy the molecules dissociate in several channels. The dissociation time found is an order of magnitude faster than the estimated IR relaxation time. Photophysical properties of both nitrogen containing and methyl-substituted PAHs are interesting in an astrophysical context in connection with identifying the aromatic component of the interstellar medium.

Klærke, B.; Holm, A. I. S.; Andersen, L. H.

2011-08-01

374

Batch leaching tests: Colloid release and PAH leachability  

SciTech Connect

The Toxicity Characteristic Leaching Procedure (TCLP) was developed by the U.S. Environmental Protection Agency to assess leaching potential of contaminants from waste, and to provide a test to classify, hazardous waste. It is a batch leaching test where a waste (such as contaminated soil) and an extraction fluid are agitated for a predetermined time. Since TCLP employs an aggressive mixing technique, it is possible that hydrophobic contaminant-laden colloidal fractions may appear as 'dissolved' constituents. In this study, TCLP was employed to determine the leachability of PAH contamination from a coal tar contaminated site. Generated colloids and the apparent aqueous concentrations of naphthalene and phenanthrene were measured at various mixing times in the extraction fluid. A mathematical model was developed that predicted the apparent aqueous contaminant concentration in the filtrate. This model accounted for the presence of colloids in the filtrate, and quantified contaminant desorption from colloids. The fraction of colloid-bound contaminant was predicted to be negligible for naphthalene. However, phenanthrene was predicted to have a significant fraction of the total contaminant in the colloidal phase, while naphthalene was primarily dissolved. The desorption model and PAH desorption data are presented here to determine the extent of colloid-facilitated desorption during leaching tests.

Bergendahl, J. [Worcester Polytechnique Institute, Worcester, MA (United States). Dept. of Civil & Environmental Engineering

2005-07-01

375

Monitoring of PAHs and alkylated PAHs in aquatic organisms after 1 month from the Solar I oil spill off the coast of Guimaras Island, Philippines.  

PubMed

Following the oil spill accident of the Solar I tanker in 2006 off the coast of Guimaras Island in the Philippines, polycyclic aromatic hydrocarbons (PAHs) and alkylated PAHs in some aquatic organisms were investigated at Luzaran in Guimaras and Taklong Islands, which were heavily polluted with spilled oil, immediately and 1 month after the accident. The concentrations of total PAHs were 11.9-52.3 ng/g dry weight in fish. Meanwhile, total PAH concentrations in shellfish were 38.0-3,102 ng/g dry weight in Luzaran and 128-236 ng/g dry weight in Taklong. Pyrene, phenanthrene, and fluoranthene were dominant in most fish and chrysene in all shellfish. Significantly higher concentrations of all alkylated homologs were detected in shellfish than in fish. These differences had two possible causes, that is, the differences between fish and shellfish could be attributed to the uptake routes and/or their metabolizing abilities. PMID:19449110

Uno, Seiichi; Koyama, Jiro; Kokushi, Emiko; Monteclaro, Harold; Santander, Sheryll; Cheikyula, J Orkuma; Miki, Shizuho; Añasco, Nathaniel; Pahila, Ida G; Taberna, Hilario S; Matsuoka, Tatsuro

2009-05-16

376

Influence of Vegetation on the In Situ Bacterial Community and Polycyclic Aromatic Hydrocarbon (PAH) Degraders in Aged PAH-Contaminated or Thermal-Desorption-Treated Soil? †  

PubMed Central

The polycyclic aromatic hydrocarbon (PAH) contamination, bacterial community, and PAH-degrading bacteria were monitored in aged PAH-contaminated soil (Neuves-Maisons [NM] soil; with a mean of 1,915 mg of 16 PAHs·kg?1 of soil dry weight) and in the same soil previously treated by thermal desorption (TD soil; with a mean of 106 mg of 16 PAHs·kg?1 of soil dry weight). This study was conducted in situ for 2 years using experimental plots of the two soils. NM soil was colonized by spontaneous vegetation (NM-SV), planted with Medicago sativa (NM-Ms), or left as bare soil (NM-BS), and the TD soil was planted with Medicago sativa (TD-Ms). The bacterial community density, structure, and diversity were estimated by real-time PCR quantification of the 16S rRNA gene copy number, temporal thermal gradient gel electrophoresis fingerprinting, and band sequencing, respectively. The density of the bacterial community increased the first year during stabilization of the system and stayed constant in the NM soil, while it continued to increase in the TD soil during the second year. The bacterial community structure diverged among all the plot types after 2 years on site. In the NM-BS plots, the bacterial community was represented mainly by Betaproteobacteria and Gammaproteobacteria. The presence of vegetation (NM-SV and NM-Ms) in the NM soil favored the development of a wider range of bacterial phyla (Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Verrucomicrobia, Actinobacteria, Firmicutes, and Chloroflexi) that, for the most part, were not closely related to known bacterial representatives. Moreover, under the influence of the same plant, the bacterial community that developed in the TD-Ms was represented by different bacterial species (Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, and Actinobacteria) than that in the NM-Ms. During the 2 years of monitoring, the PAH concentration did not evolve significantly. The abundance of gram-negative (GN) and gram-positive (GP) PAH-degrading bacteria was estimated by real-time PCR quantification of specific functional genes encoding the ? subunit of PAH-ring hydroxylating dioxygenase (PAH-RHD?). The percentage of the PAH-RHD? GN bacterial genes relative to 16S rRNA gene density decreased with time in all the plots. The GP PAH-RHD? bacterial gene proportion decreased in the NM-BS plots but stayed constant or increased under vegetation influence (NM-SV, NM-Ms, and TD-Ms).

Cebron, Aurelie; Beguiristain, Thierry; Faure, Pierre; Norini, Marie-Paule; Masfaraud, Jean-Francois; Leyval, Corinne

2009-01-01

377

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

PubMed

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

Mahler, Barbara J; Metre, Peter C Van; Wilson, Jennifer T; Musgrove, Marylynn; Burbank, Teresa L; Ennis, Thomas E; Bashara, Thomas J

2010-02-01

378

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

Microsoft Academic Search

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

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

2011-01-01

379

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

Microsoft Academic Search

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

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

2012-01-01

380

Screening of compost for PAHs and pesticides using static subcritical water extraction.  

PubMed

Static subcritical water extraction (SubWE) along with solid phase extraction (SPE) was used for the analysis of PAHs and pesticides in municipal solid waste compost. Yields obtained for PAHs in certified reference sediment (CRM 104) were acceptable. The extraction method was simple, rapid, used small sample sizes, and no sample drying was required. Analysis of samples was performed by GC/MS and HPLC. Recovery of spiked pesticides was greatest at 110 degrees C for 20 min extraction time. The optimum extraction for PAH analysis was achieved at 150 degrees C for 20 min. Addition of C-18 resin as an "alternate sorbent" upon cooling increased recovery of PAHs but not of pesticides, however, it increased the stability of atrazine and propazine at higher temperatures. Analysis of three municipal compost samples from the Dayton, OH (USA) area showed no pesticides above the detection limit, however, PAH totals for 11 PAHs were 15.97, 14.42, and 20.79 microg g(-1). The totals of six of the seven carcinogenic PAHs, for which remediation goals in the United States is 4.6 microg g(-1), were determined to be 9.89, 6.77, and 13.06 microg g(-1) dry weight. The highest PAH totals were obtained from compost containing sewage sludge. PMID:11695606

McGowin, A E; Adom, K K; Obubuafo, A K

2001-11-01

381

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

PubMed

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

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

2012-12-30

382

Multispecies and Monoculture Rhizoremediation of Polycyclic Aromatic Hydrocarbons (PAHs) from the Soil  

Microsoft Academic Search

In this study, we investigated the potential of multispecies rhizoremediation and monoculture rhizoremediation in decontaminating polycyclic aromatic hydrocarbon (PAH) contaminated soil. Plant-mediated PAH dissipation was evaluated using monoplanted soil microcosms and soil microcosms vegetated with several different grass species (Brachiaria serrata and Eleusine corocana). The dissipation of naphthalene and fluorene was higher in the “multispecies” vegetated soil compared to the

Mphekgo P. Maila; P. Randima; Thomas E. Cloete

2005-01-01

383

The behaviors and fate of polycyclic aromatic hydrocarbons (PAHs) in a coking wastewater treatment plant.  

PubMed

The occurrence, behaviors and fate of 18 PAHs were investigated in a coking wastewater treatment plant in Songshan coking plant, located in Shaoguan, Guangdong Province of China. It was found that the target compounds occurred widely in raw coking wastewater, treated effluent, sludge and gas samples. In raw coking wastewater, high molecular weight (MW) PAHs were the dominant compounds, while 3-6 ring PAHs predominated in the final effluent. The dominant compounds in gas samples were phenathrene, fluoranthene and pyrene, while they were fluoranthene, pyrene, chrysene and benzo[k]fluoranthene for sludge. The process achieved over 97% removal for all the PAHs, 47-92% of eliminations of these target compounds in liquid phase were achieved in biological stage. Different behaviors of PAHs were observed in the primary tank, anaerobic tank, aerobic tank, hydrolytic tank and coagulation tank units, while heavier and lower ones were mainly removed in anaerobic tank and aerobic tanks, respectively. Regarding the fate of PAHs, calculated fractions of mass losses for low MW PAHs due to transformation and adsorption to sludge accounted for 15-50% and 24-49%, respectively, while the rest was less than 1%. For high MW PAHs, the mass losses were mainly due to adsorption to sludge and separation with tar (contributing 56-76% and 22-39%, respectively), and the removal through transformation was less. PMID:22464861

Zhang, Wanhui; Wei, Chaohai; Chai, Xinsheng; He, Jingying; Cai, Ying; Ren, Man; Yan, Bo; Peng, Pingan; Fu, Jiamo

2012-03-31

384

Occurrence and Fate of PAHs from Road Runoff in the South Drainage Basin of Annecy Lake  

Microsoft Academic Search

The nature and concentration of Polycyclic Aromatic Hydrocarbons (PAHs) from main road runoff were evaluated in several potential deposition areas close to Annecy Lake. Investigations were conducted on sediments from road lining ditches, surface sediments, surface water of the lake, Eau Morte river, stagnant water from a natural reserve. Sixteen common PAHs were studied and the concentration determined monthly from

E. Naffrechoux; E. Combet; B. Fanget; L. Paturel; F. Berthier

2000-01-01

385

PAHs Contamination in Bank Sediment of the Yamuna River, Delhi, India  

Microsoft Academic Search

This study was performed to elucidate the distribution, concentration trend and possible sources of PAHs in bank sediment of river Yamuna in Delhi, India. The levels of 16 priority polycyclic aromatic hydrocarbons (PAHs) were analyzed during pre-monsoon, monsoon and post-monsoon seasons in the sediment fraction

Tripti Agarwal; P. S. Khillare; Vijay Shridhar

2006-01-01

386

Characteristics of nano-/ultrafine particle-bound PAHs in ambient air at an international airport.  

PubMed

Concentrations of 22 polycyclic aromatic hydrocarbons (PAHs) were estimated for individual particle-size distributions at the airport apron of the Taipei International Airport, Taiwan, on 48 days in July, September, October, and December of 2011. In total, 672 integrated air samples were collected using a micro-orifice uniform deposition impactor (MOUDI) and a nano-MOUDI. Particle-bound PAHs (P-PAHs) were analyzed by gas chromatography with mass selective detector (GC/MSD). The five most abundant species of P-PAHs on all sampling days were naphthalene (NaP), phenanthrene (PA), fluoranthene (FL), acenaphthene (AcP), and pyrene (Pyr). Total P-PAHs concentrations were 152.21, 184.83, and 188.94 ng/m(3) in summer, autumn, and winter, respectively. On average, the most abundant fractions of benzo[a]pyrene equivalent concentration (BaPeq) in different molecular weights were high-weight PAHs (79.29 %), followed by medium-weight PAHs (11.57 %) and low-weight PAHs (9.14 %). The mean BaPeq concentrations were 1.25 and 0.94 (ng/m(3)) in ultrafine particles (<0.1 ?m) and nano-particles (<0.032 ?m), respectively. The percentages of total BaPeq in nano- and ultrafine particulate size ranges were 52.4 % and 70.15 %, respectively. PMID:22821344

Lai, Chia-Hsiang; Chuang, Kuen-Yuan; Chang, Jin-Wei

2012-07-22

387

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

PubMed

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

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

2013-08-04

388

Release of PAHs Through Runoff from the Gwangan Bridge to the Coast in Busan, Korea  

Microsoft Academic Search

This study was carried out from the Gwangan Bridge in Busan, Korea in order to examine the characteristics and the amount of PAHs in runoff from Gwangan Bridge, and the consequential PAH burdens in the ocean. The runoff samples were collected in particulate and dissolved phase, and the ambient air samples were collected in particulate and gaseous phase. In this

GON OK; DONG-HWAN KIM; JU-SUEP IM; SEOK-HYONG LEE; HYUNG-SEOK KIM

2011-01-01

389

BILIARY PAH METABOLITES AS A BIOLOGICAL INDICATOR OF FISH EXPOSURE IN TRIBUTARIES OF LAKE ERIE  

EPA Science Inventory

Biliary polynuclear aromatic hydrocarbons (PAH) metabolites have been studied as a biological indicator of fish exposure to PAHs since the mid 1980's. Brown bullheads were collected from the following Lake Erie tributaries: Buffalo River (BUF), Niagara River at Love Canal (NIA)...

390

FATE OF PAH COMPOUNDS IN TWO SOIL TYPES: INFLUENCE OF VOLATILIZATION, ABIOTIC LOSS, AND BIOLOGICAL ACTIVITY  

EPA Science Inventory

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

391

FATE OF PAH COMPOUNDS IN TWO SOIL TYPES: INFLUENCE OF VOLATILIZATION, ABIOTIC LOSS AND BIOLOGICAL ACTIVITY  

EPA Science Inventory

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

392

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

Microsoft Academic Search

This paper presents a comprehensive and critical review of research on different co-composting approaches to bioremediate hydrocarbon contaminated soil, organisms that have been found to degrade PAHs, and PAH breakdown products. Advantages and limitations of using certain groups of organisms and recommended areas of further research effort are identified. Studies investigating the use of composting techniques to treat contaminated soil

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

2009-01-01

393

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

PubMed Central

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

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

2010-01-01

394

Monitoring and classification of PAH toxicity using an immobilized bioluminescent bacteria  

Microsoft Academic Search

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

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

2003-01-01

395

Levels of PAHs in soil and vegetation samples from Tarragona County, Spain  

Microsoft Academic Search

The levels of 16 polycyclic aromatic hydrocarbons (PAHs) were determined in 24 soil and 12 wild chard samples collected in Tarragona County (Catalonia, Spain), an area with an important number of chemical and petrochemical industries. Samples were also collected in urban\\/residential zones and in presumably unpolluted sites (control samples). In soils, the sum of the 16 PAHs ranged between 1002

M. Nadal; M. Schuhmacher; J. L. Domingo

2004-01-01

396

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

Microsoft Academic Search

Polycyclic aromatic (PAH) and aliphatic hydrocarbon compositions, organic carbon, nitrogen and lignin contents were determined in whole, unfractionated sediment from the Washington continental shelf and in discrete sediment fractions separated by particle size and density. At least 20 to 25% of perylene and PAH derived from pyrolytic processes and 50% of the retene measured in whole sediment are contained within

Fredrick G. Prahl; Roy Carpenter

1983-01-01

397

Haplotypes and Linkage Disequilibrium at the Phenylalanine Hydroxylase Locus, PAH, in a Global Representation of Populations  

Microsoft Academic Search

Because defects in the phenylalanine hydroxylase gene (PAH) cause phenylketonuria (PKU), PAH was studied for normal polymorphisms and linkage disequilibrium soon after the gene was cloned. Studies in the 1980s concentrated on European populations in which PKU was common and showed that haplotype-frequency variation exists between some regions of the world. In European populations, linkage disequilibrium generally was found not

Judith R. Kidd; Andrew J. Pakstis; Hongyu Zhao; Ru-Band Lu; Friday E. Okonofua; Adekunle Odunsi; Elena Grigorenko; Batsheva Bonne-Tamir; Jonathan Friedlaender; Leslie O. Schulz; Josef Parnas; Kenneth K. Kidd

2000-01-01

398

A Perspective on the Toxicity of Petrogenic PAHs to Developing Fish Embryos Related to Environmental Chemistry  

Microsoft Academic Search

Numerous studies demonstrate polynuclear aromatic hydrocarbons (PAHs) dissolved from weathered crude oil adversely affect fish embryos at 0.5 to 23 ?g\\/l. This conclusion has been challenged by studies that claim (1) much lower toxicity of weathered aqueous PAHs; (2) direct contact with dispersed oil droplets plays a significant role or is required for toxicity; (3) that uncontrolled factors (oxygen, ammonia,

Mark G. Carls; Jame