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Sample records for pah diagnostic ratios

  1. PAH dynamics in roadside environments: Influence on the consistency of diagnostic ratio values and ecosystem contamination assessments.

    PubMed

    Clment, Nathalie; Muresan, Bogdan; Hedde, Mickael; Franois, Denis

    2015-12-15

    Roadside contamination (of air, soils and organisms) by polycyclic aromatic hydrocarbons (PAHs) was examined in an arable field and a mature forest (central France). Measured contents accounted for minute fractions of the cumulative vehicular exhaust emissions. The fate of vehicular PAHs was affected by many factors, including: atmospheric load dispersal, deposition on soils and vegetation, incorporation into water and organic matter cycles, and accumulation in species. Given these empirical results, we evaluated the consistency of a set of well-known diagnostic ratios. This effort has revealed that: i) most diagnostic ratio values vary considerably across roadside samples, including exhaust emissions; and ii) the first few meters from the carriageway or the road verge/forest interface or remote areas where surface water accumulates actually define turning or inflection points in the ratio profiles. These variations constitute a major obstacle to delimitating the extent of roadside contamination due to PAHs, in addition to raising questions over the applicability of ratios routinely used to designate sources. New ratios, namely (Flt+BkF)/(Pyr+BbF) and (Flt+BkF+BghiP)/?10PAH, have been specifically developed to address this challenge. The higher consistencies exhibited among environmental compartments as well as between surface soil and exhaust emissions still yield differentiated values relative to several industrial sources. PMID:26367069

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

    PubMed

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

    2014-02-28

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

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

    PubMed

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

    2013-06-18

    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 (δ(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 δ(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

  4. Assessment of Reliability when Using Diagnostic Binary Ratios of Polycyclic Aromatic Hydrocarbons in Ambient Air PM10.

    PubMed

    Pongpiachan, Siwatt

    2015-01-01

    The reliability of using diagnostic binary ratios of particulate carcinogenic polycyclic aromatic hydrocarbons (PAHs) as chemical tracers for source characterisation was assessed by collecting PM10 samples from various air quality observatory sites in Thailand. The major objectives of this research were to evaluate the effects of day and night on the alterations of six different PAH diagnostic binary ratios: An/(An + Phe), Fluo/(Fluo + Pyr), B[a]A/(B[a]A + Chry), B[a]P/(B[a]P + B[e]P), Ind/(Ind + B[g,h,i]P), and B[k]F/Ind, and to investigate the impacts of site-specific conditions on the alterations of PAH diagnostic binary ratios by applying the concept of the coefficient of divergence (COD). No significant differences between day and night were found for any of the diagnostic binary ratios of PAHs, which indicates that the photodecomposition process is of minor importance in terms of PAH reduction. Interestingly, comparatively high values of COD for An/(An + Phe) in PM10 collected from sites with heavy traffic and in residential zones underline the influence of heterogeneous reactions triggered by oxidising gaseous species from vehicular exhausts. Therefore, special attention must be paid when interpreting the data of these diagnostic binary ratios, particularly for cases of low-molecular-weight PAHs. PMID:26745124

  5. Optimal sampling ratios in comparative diagnostic trials

    PubMed Central

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

    2014-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2009-04-01

    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 Koetice, 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 Koetice 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 Zlnsko 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.

  7. A study of polycyclic aromatic hydrocarbons concentrations and source identifications by methods of diagnostic ratio and principal component analysis at Taichung chemical Harbor near Taiwan Strait.

    PubMed

    Fang, Guor-Cheng; Wu, Yuh-Shen; Chang, Cheng-Nan; Ho, Tse-Tsung

    2006-08-01

    Fine (PM(2.5)) and Coarse (PM(2.5-10)) particulates concentrations of ambient air particle-bound polycyclic aromatic hydrocarbons (PAHs) were measured simultaneously from February 2004 to January 2005 at the Taichung Harbor (TH) sampling site near Taiwan of central Taiwan. Particle-bound polycyclic aromatic hydrocarbons (PAHs) were collected on quartz filters, the collected sample used soxhlet analytical method extracted with a dichloromethane (DCM)/n-hexane mixture (50/50, v/v) for 24h, and then the extracts were subjected to gas chromatography-mass spectrometric (GC-MS) analysis. The results indicated that vehicle emissions, coal combustion, incomplete combustion and pyrolysis of fuel and oil burning were the main source of PAHs near Taiwan Strait of central Taiwan. Diagnostic ratio and principal component analysis (PCA) were also used to characterize and identify PAHs emission source in this study. PMID:16406483

  8. The use of diagnostic ratios, biomarkers and 3-way Kohonen neural networks to monitor the temporal evolution of oil spills.

    PubMed

    Fernández-Varela, R; Gómez-Carracedo, M P; Ballabio, D; Andrade, J M

    2015-07-15

    Oil spill identification relies usually on a wealth of chromatographic data which requires advanced data treatment (chemometrics). A simple approach based on Kohonen neural networks to handle three-dimensional arrays is presented. A suite of 28 diagnostic ratios was considered to monitor six oils along four months. It was found that some traditional diagnostic ratios were not stable enough. In particular, alkylated PAHs (e.g. 1-methyldibenzothiophene, 4-methylpyrene, 27bbSTER and the TA21 and TA26 triaromatic steroids) seemed less resistant to medium-weathering than biomarkers. One (or two) ratios were found to differentiate each product: 30O, 28ab (and 25nor30ab), C3-dbt/C3-phe, 27Ts, TA26 and 29Ts characterized Ashtart, Brent, Maya, Sahara, IFO and Prestige oils, respectively. PMID:25935805

  9. Use of diagnostic ratios for studying source apportionment and reactivity of ambient polycyclic aromatic hydrocarbons over Central Europe

    NASA Astrophysics Data System (ADS)

    Dvorská, Alice; Lammel, Gerhard; Klánová, Jana

    2011-01-01

    Ratios of levels of 9 polycyclic aromatic hydrocarbons (PAHs) in air at central European sites during 1996-2008 were used to assess the suitability of 5 commonly used diagnostic ratios (DRs) for PAH source apportionment. DRs derived from a detailed literature study on emission factors were reflected in ambient air samples only at sites located near major sources. A significant seasonality was observed in a long-term time series of ambient DRs at a background site indicating possible capability of this method to reflect changes in source characteristics. The results of a mass balance study suggest that current knowledge of PAH reactivities is insufficient for a source apportionment based on DRs at receptor sites, even when limited to major types of PAH sources. However, DRs could be used to narrow down ozone and hydroxyl radical reaction rate coefficients' uncertainties: k O 3(2) of pyrene and benzo(ghi)perylene in the particulate phase seem to be ≤ 10% of the highest rate coefficient measured using model aerosols in the laboratory and k O 3(2) of indeno(1,2,3-cd)pyrene in the gas phase could be higher than previously estimated by three orders of magnitude. The suitability of DRs for source apportionment at (especially background) receptor sites cannot be expected in the general case. However, measurements carried out close to sources are in accordance with literature data suggesting that the ratios of benzo(a)anthracene/(benzo(a)anthracene + chrysene) and indeno(123cd)pyrene/(indeno(123cd)pyrene + benzo(ghi)perylene) are capable of distinguishing between traffic and residential heating, while the ratio of anthracene/(anthracene + phenanthrene) was the least useful DR due to its low variability.

  10. Properties of Polycyclic Aromatic Hydrocarbons in the Northwest Photon Dominated Region of NGC 7023. III. Quantifying the Traditional Proxy for PAH Charge and Assessing its Role

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

    Polycyclic aromatic hydrocarbon (PAH) emission in the Spitzer/IRS spectral map of the northwest photon dominated region (PDR) in NGC 7023 is analyzed. Here, results from fitting the 5.2-14.5 ?m spectrum at each pixel using exclusively PAH spectra from the NASA Ames PAH IR Spectroscopic Database (www.astrochem.org/pahdb/) and observed PAH band strength ratios, determined after isolating the PAH bands, are combined. This enables the first quantitative and spectrally consistent calibration of PAH charge proxies. Calibration is straightforward because the 6.2/11.2 ?m PAH band strength ratio varies linearly with the ionized fraction (PAH ionization parameter) as determined from the intrinsic properties of the individual PAHs comprising the database. This, in turn, can be related to the local radiation field, electron density, and temperature. From these relations diagnostic templates are developed to deduce the PAH ionization fraction and astronomical environment in other objects. The commonly used 7.7/11.2 ?m PAH band strength ratio fails as a charge proxy over a significant fraction of the nebula. The 11.2/12.7 ?m PAH band strength ratio, commonly used as a PAH erosion indicator, is revealed to be a better tracer for PAH charge across NGC 7023. Attempting to calibrate the 12.7/11.2 ?m PAH band strength ratio against the PAH hydrogen adjacency ratio (duo+trio)/solo is, unexpectedly, anti-correlated. This work both validates and extends the results from Paper I and Paper II.

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

    PubMed

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

    2013-11-01

    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

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

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

    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.

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

    PubMed

    Karaca, Gizem

    2016-02-01

    The objectives of this study were to identify regional variations in soil polycyclic aromatic hydrocarbon (PAH) contamination in Bursa, Turkey, and to determine the distributions and sources of various PAH species and their possible sources. Surface soil samples were collected from 20 different locations. The PAH concentrations in soil samples were analyzed using gas chromatography-mass spectrometry (GC-MS). The total PAH concentrations (?12 PAH) varied spatially between 8 and 4970ng/g dry matter (DM). The highest concentrations were measured in soils taken from traffic+barbecue+ residential areas (4970ng/g DM) and areas with cement (4382 ng/g DM) and iron-steel (4000ng/g DM) factories. In addition, the amounts of ?7 carcinogenic PAH ranged from 1 to 3684ng/g DM, and between 5 and 74% of the total PAHs consisted of such compounds. Overall, 4-ring PAH compounds (Fl, Pyr, BaA and Chr) were dominant in the soil samples, with 29-82% of the ?12 PAH consisting of 4-ring PAH compounds. The ?12 BaPeq values ranged from 0.1 to 381.8ng/g DM. Following an evaluation of the molecular diagnostic ratios, it was concluded that the PAH pollution in Bursa soil was related to pyrolytic sources; however, the impact of petrogenic sources should not be ignored. PMID:26658619

  14. Diagnostic value of plasma aldosterone/potassium ratio in hypoaldosteronism.

    PubMed

    Shiah, C J; Wu, K D; Tsai, D M; Liao, S T; Siauw, C P; Lee, L S

    1995-05-01

    The diagnosis of hypoaldosteronism usually depends upon a combination of abnormal clinical and laboratory findings. The most common abnormality in hypoaldosteronism is hyperkalemia, which may be combined with sodium depletion. In the present study, 5 of 16 patients diagnosed with isolated hypoaldosteronism (IHA) had sodium depletion due to renal salt wasting, and four patients had normokalemia. Of these 16 IHA patients, 70% had subnormal baseline and stimulated plasma renin activity (PRA). Six patients diagnosed with type I pseudohypoaldosteronism (PHA) had normal or high PRA and plasma aldosterone concentrations (PAC). In 11 control subjects, supine PAC correlated positively with serum potassium (SK), and PAC stimulated by furosemide and ambulation correlated with the 24-hour urinary potassium excretion (UK). However, these correlations were not found in IHA and PHA patients. The ratio of UK/UNa+K and UNa/UK correlated with the stimulated PAC when the IHA and control subjects were taken as a whole. However, these electrolyte excretion parameters bore no relationship to the supine PAC. The stimulated PAC/SK ratio was used to discriminate the three groups; all IHA patients had a ratio below 3. The results indicate that stimulated PAC reflects the bioactivity of aldosterone on the collecting tubule, and the stimulated PAC/SK ratio is useful for the diagnosis of hypoaldosteronism and pseudohypoaldosteronism. PMID:7613258

  15. Enhanced PM10 bounded PAHs from shipping emissions

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

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

  16. Indoor and outdoor air pollution of polycyclic aromatic hydrocarbons (PAHs) in Xuanwei and Fuyuan, China.

    PubMed

    Lv, Jungang; Xu, Renji; Wu, Guoping; Zhang, Qinghua; Li, Yingming; Wang, Pu; Liao, Chunyang; Liu, Jiyan; Jiang, Guibin; Wei, Fusheng

    2009-07-01

    Xuanwei and Fuyuan, located in the Yunnan province in southwest of China, are known to have a high incidence of lung cancer caused by indoor airborne polycyclic aromatic hydrocarbons (PAHs) generated during bituminous coal combustion for heating and cooking in unvented households. In this study, indoor and outdoor air was sampled at 38 sampling sites around these areas in January 2007. The concentrations of 16 PAHs were analyzed. The sources of PAHs in these two counties were also investigated. Quartz filters and polyurethane foam were used to collect particle-bound PAHs (p-PAHs) and gas-phase PAHs (g-PAHs), respectively. The concentrations of benzo(a)pyrene (Bap), the best index for PAHs carcinogenicity, were higher in indoor air than that in outdoor air. Bap levels in all the indoor air samples were higher than the national criteria (1.0 ng m(-3)) in China, but were much lower than those in previous studies in the same areas. Bap levels in 20 out of the 29 outdoor air samples were higher than the national criteria (10 ng m(-3)) of China. Significant differences in the gas/particle partition of PAHs were found between the indoor and the outdoor air samples. Principal component analysis (PCA) in combination with diagnostic ratios indicated that coal combustion was the predominant source for both indoor and outdoor PAHs pollution. PMID:20449226

  17. Distribution characteristics and source apportionment of polycyclic aromatic hydrocarbons (PAHs) in the Liao River drainage basin, northeast China.

    PubMed

    Hu, Jian; Liu, Congqiang; Zhang, Guoping; Zhang, Yanlin; Li, Siliang; Zhao, Zhiqi; Liu, Baojian; Guo, Qinjun

    2016-04-01

    The Liao River drainage basin, which is one of China's seven major rivers basins, is located in northeast China. This region is characterized by important industrial bases including steel factories and oil and chemical plants, all of which have the potential to contribute pollutants to the drainage basin. In this study, 16 polycyclic aromatic hydrocarbons (PAHs) in water and suspended particulate matter (SPM) in the major rivers of the Liao River drainage basin were identified and quantified by gas chromatography mass spectrometry (GC/MS). The total PAH concentrations ranged from 0.4 to 76.5 μg/g (dry weight) in SPM and 32.6 to 108 ng/L in surface water, respectively. Low-ring PAHs (including two- and three-ring PAHs) were dominant in all PAH samples, and the level of low-ring PAHs in surface water was higher than that in SPM. The proportion of two-ring PAHs was the highest, accounting for an average of 68.2 % of the total PAHs in surface water, while the level of three-ring PAHs was the highest in SPM, with an average of 66.3 %. When compared with other river systems, the concentrations of PAHs in the Liao River drainage basin were lower. Identification of the emission sources based on diagnostic ratios suggested petroleum and fossil fuel combustion were important contribution to PAHs in the study area. PMID:26972927

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

    PubMed

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

    2014-11-15

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

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

    SciTech Connect

    Douglas, G.S.; Sara McMillen

    1996-12-31

    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.

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

    SciTech Connect

    Douglas, G.S.; Sara McMillen

    1996-01-01

    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.

  1. The Diagnostics of Laser-Induced Fluorescence (LIF) Spectra of PAHs in Flame with TD-DFT: Special Focus on Five-Membered Ring.

    PubMed

    Liu, Peng; He, Zhenwu; Hou, Gao-Lei; Guan, Bin; Lin, He; Huang, Zhen

    2015-12-31

    The electronic emission characteristics of 13 gas-phase PAHs, ranging from phenlylacetylene to rubicene, were investigated to diagnose laser-induced fluorescence (LIF) spectra of PAHs in flame by DFT, TD-DFT, and premixed flame modeling methods. It was found that the maximum emission wavelengths of the PAHs with five-membered ring are located in visible region and insensitive to the number of C atoms. However, the fluorescence wavelengths of the PAHs without five-membered rings increase with the number of C atoms due to the reduced HOMO-LUMO gap. In addition, the fluorescence wavelength of the PAHs without five-membered rings with linear arrangement is longer than that of PAHs with nonlinear arrangement. According to the Franck-Condon principle, the vibrationally resolved electronic fluorescence spectra were obtained. The results show that fluorescence bandwidth of the PAHs with five-membered rings is much broader than that of the PAHs without five-membered rings. The concentration of PAHs was calculated by using the premixed flat-flame model with KM2 mechanism. On the basis of the fluorescence bandwidth and the concentration of the PAHs, the potentially fluorescence distribution of PAHs in flame was mapped. One can distinguish the specific PAHs according to the mapped fluorescence distribution of PAHs in this study. It was found that naphthalene should be responsible for the fluorescence located in the 312-340 nm region in the flame. 1-Ethynylnaphthalene is the most possible candidate to emit the fluorescence located in the 360-380 nm region. The fluorescence signals with the wavelength longer than 500 nm are likely emitted by the PAHs with five-membered rings. This study contributes to enhance the selectivity of PAHs in LIF technology, especially in the visible region. PMID:26645298

  2. Non-differential measurement error does not always bias diagnostic likelihood ratios towards the null

    PubMed Central

    Fosgate, GT

    2006-01-01

    Diagnostic test evaluations are susceptible to random and systematic error. Simulated non-differential random error for six different error distributions was evaluated for its effect on measures of diagnostic accuracy for a brucellosis competitive ELISA. Test results were divided into four categories: <0.25, 0.25 0.349, 0.35 0.499, and ? 0.50 proportions inhibition for calculation of likelihood ratios and diagnostic odds ratios. Larger variance components of the error structure resulted in larger accuracy attenuations as measured by the area under the receiver-operating characteristic curve and systematic components appeared to cause little bias. Added error caused point estimates of likelihood ratios to be biased towards the null value (1.0) for all categories except 0.25 0.349. Results for the 0.35 0.499 category also extended beyond the null value for some error structures. Diagnostic odds ratios were consistently biased towards the null when the <0.25 category was considered the reference level. Non-differential measurement error can lead to biased results in the quantitative evaluation of ELISA and the direction is not always towards the null value. PMID:16846512

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

    PubMed Central

    2014-01-01

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

  4. DNA methylation ratio variability may impede clinical application of cancer diagnostic markers.

    PubMed

    Burke, Daniel; Fu, Shuang; Forbes-Smith, Michael; Bhat, Somanath; Partis, Lina; Coldham, Thosaporn; Frenkel, Robert; Emslie, Kerry R

    2014-10-01

    Hypermethylation at promoter regions of tumour suppressor genes is diagnostic for many cancers. Many genomic regions that may be the targets for clinical diagnostic assays have been identified through use of measuring systems reliant on bisulphite conversion, but few of these promising markers are in clinical use. The comparability of a widely used DNA methylation measuring system involving bisulphite conversion was evaluated by supplying three experienced centres with methylated DNA reference material mixtures that were independently prepared and characterised by mass spectrometry and high-pressure liquid chromatography. A replication scheme was designed to evaluate reproducibility of key analytical steps within and between laboratories by regression analysis. In general, methylation was underestimated and methylation ratio values were highly variable. The difference in methylation ratio between CpG sites was the key contributor to variable results. The CpG site effect followed a similar pattern at all centres and at all methylation levels examined indicating that sequence context had a major effect on methylation ratio measurement using the bisulphite conversion process. The magnitude of underestimation combined with the variability of measurements between CpG sites compromises the concept of measuring genomic regional methylation by averaging the methylation ratios of many CpG sites. There were no significant differences in replicate bisulphite conversions or sample work-up and instrument analysis at each centre thus making this technique suitable for comparative intralaboratory investigations. However, it may not be suitable for a routine diagnostic assay without extensive standardisation efforts. PMID:24948089

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

    PubMed

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

    2014-10-01

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

  6. NON-EQUILIBRIUM IONIZATION EFFECTS ON THE DENSITY LINE RATIO DIAGNOSTICS OF O IV

    SciTech Connect

    Olluri, K.; Gudiksen, B. V.; Hansteen, V. H.

    2013-04-10

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

  7. The platelet amyloid precursor protein ratio as a diagnostic marker for Alzheimer's disease in Thai patients.

    PubMed

    Srisawat, Chatchawan; Junnu, Sarawut; Peerapittayamongkol, Chayanon; Futrakul, Aree; Soi-ampornkul, Rungtip; Senanarong, Vorapun; Praditsuwan, Rungnirand; Assantachai, Prasert; Neungton, Neelobol

    2013-05-01

    The platelet amyloid precursor protein (APP) ratio has recently been shown to be a promising diagnostic marker for Alzheimer's disease (AD). To evaluate its usefulness in Thai patients, platelet APP was analyzed by immunoblotting. The APP ratio was calculated as the ratio of the combined band density of the 120-kD and 130-kD isoforms compared to that of the 110-kD isoform. The mean ages (and ranges) of 27 normal and 13 AD-affected subjects were 68.3 (60-84) and 79.3 (70-97) years, respectively. The Thai Mental State Examination (TMSE) scores demonstrated that the AD patients had significantly poorer cognitive functions than the normal subjects, with mean TMSE scores of 20.3 and 27.6 (maximum score of 30 points), respectively (p<0.05). The platelet APP ratios of the AD patients were significantly lower than those of normal subjects: values (mean standard deviation) were 7.32 1.29 and 9.13 3.00, respectively (p<0.05) for AD patients and normal subjects. However, the ranges of the APP ratios from both groups markedly overlapped, which precluded the establishment of a cutoff level to differentiate between the AD and normal subjects. In addition, no significant correlations were observed between the platelet APP ratio and the TMSE score or between the APP ratio and the serum cholesterol in this study, in contrast to previous reports. PMID:23453155

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

    NASA Astrophysics Data System (ADS)

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

    2012-07-01

    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.

  9. Distribution, source apportionment, and transport of PAHs in sediments from the Pearl River Delta and the northern South China Sea

    SciTech Connect

    Luo, X.J.; Chen, S.J.; Mai, B.X.; Sheng, G.Y.; Fu, J.M.; Zeng, E.Y.

    2008-07-15

    Polycyclic aromatic hydrocarbons (PAHs) were measured in 59 surface sediments from rivers in the Pearl River Delta and the northern continental shelf of the South China Sea. Total PAH concentrations varied from 138 to 6,793 ng/g dry weight. The sources of PAH inputs to sediments in the Pearl River Delta were qualitatively and quantitatively determined by diagnostic ratios and principal components analysis with multiple linear regression. The results showed that on average coal and wood combustion, petroleum spills, vehicle emissions, and nature sources contributed 36%, 27%, 25%, and 12% of total PAHs, respectively. Coal and biomass combustion was the main source of PAHs in sediments of the South China Sea, whereas petroleum combustion was the main source of pyrolytic PAHs in riverine and estuarine sediments of the Pearl River Delta. Perylene was formed in situ in river sediments and then transported to coastal areas along with other PAHs. The relative abundance of perylene from five-ring PAHs can be used to estimate the contribution of riverine-discharged PAHs to coastal sediments.

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

    PubMed

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

    2014-07-01

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

  11. Characterizations, relationship, and potential sources of outdoor and indoor particulate matter bound polycyclic aromatic hydrocarbons (PAHs) in a community of Tianjin, Northern China.

    PubMed

    Han, B; Bai, Z; Liu, Y; You, Y; Xu, J; Zhou, J; Zhang, J; Niu, C; Zhang, N; He, F; Ding, X

    2015-06-01

    Polycyclic aromatic hydrocarbons (PAHs) are among the most toxic air pollutants in China. However, because there are unsubstantial data on indoor and outdoor particulate PAHs, efforts in assessing inhalation exposure and cancer risk to PAHs are limited in China. This study measured 12 individual PAHs in indoor and outdoor environments at 36 homes during the non-heating period and heating period in 2009. Indoor PAH concentrations were comparable with outdoor environments in the non-heating period, but were lower in the heating period. The average indoor/outdoor ratios in both sampling periods were lower than 1, while the ratios in the non-heating period were higher than those in the heating period. Correlation analysis and coefficient of divergence also verified the difference between indoor and outdoor PAHs, which could be caused by high ventilation in the non-heating period. To support this conclusion, linear and robust regressions were used to estimate the infiltration factor to compare outdoor PAHs to indoor PAHs. The calculated infiltration factors obtained by the two models were similar in the non-heating period but varied greatly in the heating period, which may have been caused by the influence of ventilation. Potential sources were distinguished using a diagnostic ratio and a mixture of coal combustion and traffic emission, which are major sources of PAHs. PMID:25039922

  12. Regional assessment of PAHs contamination in SE Brazil using brown mussels (Perna perna Linnaeus 1758).

    PubMed

    Yoshimine, Renato V; Carreira, Renato S; Scofield, Arthur L; Wagener, Angela L R

    2012-11-01

    Cultured and native brown mussels (Perna perna Linnaeus 1758) were used to evaluate the contamination by PAHs in the SE Brazilian coastal zone. Mean concentrations of total PAH (38 parental and alkylated compounds) and cluster analysis revealed that: (i) mussel farms (32.7-70.1 ng g(-1)) are located in uncontaminated areas; (ii) coastal rockyshore areas (89.7 25.8 ng g(-1)) have low level of contamination; and (iii) the Guanabara Bay (760.9 456.3 ng g(-1)) is chronically contaminated by hydrocarbons, which is consistent with previous results. PAH profiles and diagnostic ratios suggested mixed petrogenic and pyrolitic sources for group (ii) and petrogenic sources for group (iii). The levels of PAH in the cultured and native mussels are below threshold values for safe food, even in Guanabara Bay, and thus in such cases other contaminants and pathogens should be considered in order to evaluate the quality of shellfish for human consumption. PMID:22850188

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

    SciTech Connect

    Soto, Kurt T.; Martin, Crystal L.

    2012-11-15

    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.

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

    PubMed

    Sarkar, Sayantan; Khillare, P S

    2013-02-01

    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

  15. Conceptualization of category-oriented likelihood ratio: a useful tool for clinical diagnostic reasoning

    PubMed Central

    2011-01-01

    Background In the diagnostic reasoning process medical students and novice physicians need to be made aware of the diagnostic values of the clinical findings (including history, signs, and symptoms) to make an appropriate diagnostic decision. Diagnostic reasoning has been understood in light of two paradigms on clinical reasoning: problem solving and decision making. They advocate the reasoning strategies used by expert physicians and the statistical models of reasoning, respectively. Evidence-based medicine (EBM) applies decision theory to the clinical diagnosis, which can be a challenging topic in medical education. This theoretical article tries to compare evidence-based diagnosis with expert-based strategies in clinical diagnosis and also defines a novel concept of category-oriented likelihood ratio (LR) to propose a new model combining both aforementioned methods. Discussion Evidence-based medicine advocates the use of quantitative evidence to estimate the probability of diseases more accurately and objectively; however, the published evidence for a given diagnosis cannot practically be utilized in primary care, especially if the patient is complaining of a nonspecific problem such as abdominal pain that could have a long list of differential diagnoses. In this case, expert physicians examine the key clinical findings that could differentiate between broader categories of diseases such as organic and non-organic disease categories to shorten the list of differential diagnoses. To approach nonspecific problems, not only do the experts revise the probability estimate of specific diseases, but also they revise the probability estimate of the categories of diseases by using the available clinical findings. Summary To make this approach analytical and objective, we need to know how much more likely it is for a key clinical finding to be present in patients with one of the diseases of a specific category versus those with a disease not included in that category. In this paper, we call this value category-oriented LR. PMID:22094044

  16. Source apportionment of gaseous and particulate PAHs from traffic emission using tunnel measurements in Shanghai, China

    NASA Astrophysics Data System (ADS)

    Liu, Ying; Wang, Siyao; Lohmann, Rainer; Yu, Na; Zhang, Chenkai; Gao, Yi; Zhao, Jianfu; Ma, Limin

    2015-04-01

    Understanding sources and contributions of gaseous and particulate PAHs from traffic-related pollution can provide valuable information for alleviating air contamination from traffic in urban areas. On-road sampling campaigns were comprehensively conducted during 2011-2012 in an urban tunnel of Shanghai, China. 2-3 rings PAHs were abundant in the tunnel's gas and particle phases. Diagnostic ratios of PAHs were statistically described; several were significantly different between the gas and particle phases. Principal component analysis (PCA), positive matrix factorization (PMF), bivariate correlation analysis and multiple linear regression analysis (MLRA) were applied to apportion sources of gaseous and particulate PAHs in the tunnel. Main sources of the gaseous PAHs included evaporative emission of fuel, high-temperature and low-temperature combustion of fuel, accounting for 50-51%, 30-36% and 13-20%, respectively. Unburned fuel particles (56.4-78.3%), high-temperature combustion of fuel (9.5-26.1%) and gas-to-particle condensation (12.2-17.5%) were major contributors to the particulate PAHs. The result reflected, to a large extent, PAH emissions from the urban traffic of Shanghai. Improving fuel efficiency of local vehicles will greatly reduce contribution of traffic emission to atmospheric PAHs in urban areas. Source apportionment of PM10 mass was also performed based on the organic component data. The results showed that high-temperature combustion of fuel and gas-to-particle condensation contributed to 15-18% and 7-8% of PM10 mass, respectively, but 55-57% of the particle mass was left unexplained. Although the results from the PCA and PMF models were comparable, the PMF method is recommended for source apportionment of PAHs in real traffic conditions. In addition, the combination of multivariate statistical method and bivariate correlation analysis is a useful tool to comprehensively assess sources of PAHs.

  17. Speciation of atmospheric polycyclic aromatic hydrocarbons (PAHs) present during fog time collected submicron particles.

    PubMed

    Singh, Dharmendra Kumar; Sharma, Swati; Habib, Gazala; Gupta, Tarun

    2015-08-01

    Airborne submicron particles (PM1) were collected using PM1 sampler during the fog-dominated days (December 2013-January 2014). PM1 values varied between 58.12 ?g/m(3) and 198.75 ?g/m(3), and average mass concentration was 162.33??38.25 ?g/m(3) while total average concentration of particle-associated polycyclic aromatic hydrocarbon (PAHs) determined was 616.31??30.31 ng/m(3). This is a signal for an alarming high pollution level at this site situated in the Indo-Gangetic Plain (IGP). PAHs were extracted from filters using toluene and acetonitrile. Quantitative measurements of polycyclic aromatic hydrocarbons (PAHs) were carried out using the high performance liquid chromatography (HPLC) technique. The extracts were analyzed for 16 target polycyclic aromatic hydrocarbons (PAHs) including carcinogenic compound benzo(a)pyrene (19.86??38.98 ng/m(3)). Fluoranthene, benzo(a)anthracene, anthracene, and fluorene were the predominant compounds found in the samples collected during foggy days. Based on number of rings, four-ring PAH compounds had maximum contribution (43%) in this fog time collected submicron particles followed by three-ring (21%), five-ring (20%), six-ring (13%), and two-ring (3%), respectively. In winter and foggy days, wood and coal combustion and biomass burning also significantly contribute to the PAH levels. However, diagnostic ratio suggests diesel emissions as the prime source of PAHs at this sampling site. PMID:25903173

  18. Diagnostic value of strain ratio measurement in differential diagnosis of thyroid nodules coexisted with Hashimoto thyroiditis

    PubMed Central

    Wang, Jianhong; Li, Ping; Sun, Lingling; Sun, Yongmei; Fang, Shibao; Liu, Xuejun

    2015-01-01

    Objective: To evaluate the differential diagnostic potential of lesion stiffness assessed by the sonoelastographic strain index ratio (SR) for thyroid nodules coexist with Hashimoto thyroiditis (HT). Methods: A total of 50 focal thyroid nodules from 36 patients with HT (mean age 38.4 years; range 19-77) scheduled for fine-needle aspiration or thyroid surgery were included. After a routine conventional ultrasound evaluation, real-time ultrasound elastography examinations were performed. Strain and area ratios of each lesion were calculated within the same machine. Histological diagnosis was used as the reference standard. The elastography images were scored according to the Asteria elasticity score. The area under the curve (AUC) and cut-off point were obtained by receiver operating curve (ROC). Sensitivity, specificity and accuracy were compared. Results: A total of 38 nodules were benign and 12 were malignant on pathology. The mean strain ratios of benign and malignant lesions were 2.89 and 7.83 respectively. When a cut-off point of 5.03 was used, SR had a sensitivity of 75.0%, a specificity of 92.1% and an accuracy of 84.0%. The AUC values were 0.836. The diagnostic accuracy of the SR was superior to that of elastographic score. Conclusion: Real-time elastography is a promising tool for differential diagnosis of thyroid nodules coexist with HT, and SR measurement could be an effective predictor. The best cut-off point for benign and malignant nodules in patients with HT was 5.03. PMID:26131268

  19. Distributions and source apportionment of sediment-associated polycyclic aromatic hydrocarbons (PAHs) and hopanes in rivers and estuaries of Peninsular Malaysia.

    PubMed

    Keshavarzifard, Mehrzad; Zakaria, Mohamad Pauzi; Hwai, Tan Shau; Yusuff, Ferdius Mohamat; Mustafa, Shuhaimi

    2015-06-01

    In this study, the distributions and sources of sediment-associated polycyclic aromatic hydrocarbons (PAHs) and hopanes in the Malaysian rivers and estuaries were evaluated. The concentrations of 16 USEPA PAHs varied from 225.5 to 293.9 (Perlis River), 195.2 to 481.2 (Kedah River), 791.2 to 1995.4 (Merbok River), 231.2 to 426.7 (Perak River), and 3803.2 to 7442.7 ng g(-1) (Klang River) dry weight. PAHs can be classified as moderate in the Perlis, Kedah, and Perak Rivers, moderate to high in the Merbok River, and high to very high in the Klang River. The comparison of PAHs with sediment quality guidelines (SQGs) indicates that occasionally adverse biological effects may occur from total PAHs, low molecular weight (LMW), and high molecular weight (HMW) PAHs at stations 1, 2, and 3 of the Klang River and from total PAHs at station 2 of the Merbok River. The diagnostic ratios of individual PAHs indicate both petrogenic and pyrogenic origin PAHs with significant dominance of pyrogenic sources in the study areas. The results suggest that Malaysian sediments had hopane ratios (C29/C30) similar to MECO suggesting MECO as a major source of the petroleum hydrocarbons found in the sediments, which is consistent with results reported in previous studies. These findings demonstrate that effective and improved environmental regulations in Malaysia have shifted the source of petroleum hydrocarbons from petrogenic to pyrogenic origin. PMID:25604562

  20. Using Polycyclic Aromatic Hydrocarbons (PAHs) as a chemical proxy to indicate Tsunami 2004 backwash in Khao Lak coastal area, Thailand

    NASA Astrophysics Data System (ADS)

    Tipmanee, D.; Deelaman, W.; Pongpiachan, S.; Schwarzer, K.; Sompongchaiyakul, P.

    2012-05-01

    In this study, we attempted to use PAHs as a chemical proxy to trace the transport of land-derived materials caused by the tsunami backwash to better understand how it may have affected the distribution of sedimentary deposition throughout the seabed of Khao Lak coastal areas. By analyzing the compositions of sedimentary PAHs in combination with application of the multivariate descriptive statistical techniques, PAHs were proven to be a promising chemical proxy to indicate the tsunami backwash in the study area. Their spatial distribution could indicate that the tsunami backwash plays an important role in transporting anthropogenic PAHs to the nearby coastal area as far as approximately 25 km from the shoreline. In addition, the results from diagnostic PAH isomer ratios suggested that road paving asphalt, originated from heavy erosion by the tsunami wave in front of Pakarang Cape, was among the identified sources of PAHs. Principle Component Analysis (PCA) results provided 2 estimated land-derived sources of PAHs, which were the road dust and oil burning sources. These estimated signature sources clearly support our hypothesis that PAHs were transported from the potential sources on land and deposited into the near-shore seabed during tsunami backwash.

  1. Sources appointment and ecological risk assessment of polycyclic aromatic hydrocarbons (PAHs) in sediments of Erhai Lake, a low-latitude and high-altitude lake in southwest China.

    PubMed

    Hezhong, Yuan; Enlou, Zhang; Qi, Lin; Rong, Wang; Enfeng, Liu

    2016-03-01

    Sixteen polycyclic aromatic hydrocarbons (PAHs) were analyzed from the surficial sediments in Erhai Lake, a plateau lake in China. The results showed that except for acenaphthylene (Ace) Ace and Dibenz(a,h)anthracene (DBA), the central region contained individual PAHs at concentrations lower than those in other lake regions. Total concentration of the PAHsPAHs) in the sediments from Erhai Lake ranged from 32.42 to 558.53 mg/kg with a mean value of 256.70 mg/kg. The maximum value of ΣPAHs was observed in the north region of the lake and more than 10-fold higher than the minimum values. Moreover, high molecular weight (HMW) PAHs, especially 5-ring PAHs, accounted for higher ratios up to 76 % relative to other PAHs compound in almost all sampling sites. Molecular diagnostic ratios including anthtacene (Ant)/(Ant + phenanthrene (Phe)), fluoranthene (Flt)/(Flt + pyrene (Pyr)), benz(a)anthracene (BaA)/(BaA + chrysene (Chr)), and indeno(1,2,3-cd)pyrene (IPY)/(IPY + benz(g,h,i)perylene (BPE)) were recorded at all sampling sites and indicated that the origin of PAHs in Erhai Lake was predominately pyrolytic. Furthermore, principal component analysis with component dominating by HMW PAHs showed that combustion origins were the primary contamination sources of PAHs in the sediments of Erhai Lake. Finally, ecological risk assessment indicated that the sediments from Erhai Lake are exposed to potential low risk for ΣPAHs, and the ecological risk decreases in the order of northern region > southern region > central region. PMID:26507728

  2. Long-term monitoring and seasonal analysis of polycyclic aromatic hydrocarbons (PAHs) measured over a decade in the ambient air of Porto, Portugal.

    PubMed

    Albuquerque, M; Coutinho, M; Borrego, C

    2016-02-01

    The present paper reports the analytical results of PAHs concentrations in ambient air obtained in the PM10 and gas-phase, from 2004 to 2014, in Porto, Portugal. As part of a monitoring programme conducted by IDAD - Institute of Environment and Development and supported by the regional municipal solid waste (MSW) management authorities, an extensive database of PAH concentrations in ambient air was collected in Porto's metropolitan area. During this period a total of 201 samples were collected in two sites classified as suburban. Analytical results showed a clear decreasing trend of total PAHs (∑PAH) and benzo[a]pyrene (BaP) levels during the period of study, especially in the first years of monitoring. The average annual concentrations of BaP were, throughout the monitoring period, lower than the target value for the annual average (1ngm(-3)) defined in the European legislation. PAHs levels showed a strong seasonality, with higher concentrations values during the colder months. The winter/summer ratio of ∑PAH for the eleven years of study was 5, revealing the seasonal variation of PAHs in the studied area. The estimated toxic equivalency factors (TEFs) used to assess the contribution of the carcinogenic potential, confirmed a significant presence of the moderately active carcinogenic BaP and dibenz[ah]anthracene (DahA) in the samples collected in Porto. The ratio values of individual PAHs concentrations were used as diagnostic tool to identify the possible origin of PAH in the ambient air of Porto. Based on diagnostic ratios, it may be concluded that automobile traffic emissions, mainly related to diesel vehicles, were the major contribution of PAH levels in the ambient air, although some others contributions, such as coal and wood combustion, were identified. PMID:26599144

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

    NASA Astrophysics Data System (ADS)

    Srivastava, A. K.; et al.

    2006-11-01

    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.

  4. PAHs in Translucent Interstellar Clouds

    NASA Astrophysics Data System (ADS)

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

    2011-05-01

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

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

    PubMed Central

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

    2014-01-01

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

  6. Distribution and source apportionment of polycyclic aromatic hydrocarbons (PAHs) in forest soils from urban to rural areas in the Pearl River Delta of Southern China.

    PubMed

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

    2014-03-01

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

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

    PubMed Central

    Siadaty, Mir Said; Shu, Jianfen

    2004-01-01

    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. PMID:15588327

  8. Temporal trends of polycyclic aromatic hydrocarbons (PAHs) in Dreissena polymorpha specimens from Lake Maggiore (Northern Italy).

    PubMed

    Parolini, Marco; Binelli, Andrea

    2014-01-01

    The Lake Maggiore (Northern Italy) has been recognized as an aquatic environment heavily contaminated by persistent organic pollutants, mainly organochlorine compounds, but to date limited information is available regarding another class of widespread and hazardous pollutants, such as the polycyclic aromatic hydrocarbons (PAHs). The aim of this study was to investigate seasonal and temporal trends of 18 PAHs accumulated in native Dreissena polymorpha specimens during a 5-year biomonitoring program, as well as to identify the possible PAH emission sources by using isomeric diagnostic ratios. Zebra mussels were sampled both in their pre- (May) and post-reproductive (September) stage over the 2008-2012 period in eight sampling stations covering the whole lake shoreline. PAH concentrations were measured through gas chromatography coupled to mass spectrometry. A notable PAH contamination following an increasing temporal trend was noticed in bivalves from all the sampling stations, with the benzo(?)anthracene as the predominant compound. An overall increase in PAH levels was found in the post-reproductive surveys, indicating a marked seasonality of this contamination probably due to the increase in touristic activity during spring-summer months. PMID:24532210

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

    NASA Astrophysics Data System (ADS)

    Agudelo-Castañeda, Dayana Milena; Teixeira, Elba Calesso

    2014-10-01

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

  10. Multimedia Model for Polycyclic Aromatic Hydrocarbons (PAHs) and Nitro-PAHs in Lake Michigan

    PubMed Central

    2015-01-01

    Polycyclic aromatic hydrocarbon (PAH) contamination in the U.S. Great Lakes has long been of concern, but information regarding the current sources, distribution, and fate of PAH contamination is lacking, and very little information exists for the potentially more toxic nitro-derivatives of PAHs (NPAHs). This study uses fugacity, food web, and Monte Carlo models to examine 16 PAHs and five NPAHs in Lake Michigan, and to derive PAH and NPAH emission estimates. Good agreement was found between predicted and measured PAH concentrations in air, but concentrations in water and sediment were generally under-predicted, possibly due to incorrect parameter estimates for degradation rates, discharges to water, or inputs from tributaries. The food web model matched measurements of heavier PAHs (≥5 rings) in lake trout, but lighter PAHs (≤4 rings) were overpredicted, possibly due to overestimates of metabolic half-lives or gut/gill absorption efficiencies. Derived PAH emission rates peaked in the 1950s, and rates now approach those in the mid-19th century. The derived emission rates far exceed those in the source inventories, suggesting the need to reconcile differences and reduce uncertainties. Although additional measurements and physiochemical data are needed to reduce uncertainties and for validation purposes, the models illustrate the behavior of PAHs and NPAHs in Lake Michigan, and they provide useful and potentially diagnostic estimates of emission rates. PMID:25373871

  11. Exposure measurement, risk assessment and source identification for exposure of traffic assistants to particle-bound PAHs in Tianjin, China.

    PubMed

    Xue, Xiaodan; You, Yan; Wu, Jianhui; Han, Bin; Bai, Zhipeng; Tang, Naijun; Zhang, Liwen

    2014-02-01

    To investigate the levels of exposure to particulate-bound polycyclic aromatic hydrocarbon (PAH) and to estimate the risk these levels pose to traffic assistants (TAs) in Tianjin (a megacity in North China), a measurement campaign (33 all-day exposure samples, 25 occupational-exposure samples and 10 indoor samples) was conducted to characterize the TAs' exposure to PAHs, assess the cancer risk and identify the potential sources of exposure. The average total exposure concentration of 14 PAHs was approximately 2871 +/- 928 ng/m3 (on-duty), and 1622 +/- 457 ng/m3 (all-day). The indoor PAHs level was 1257 +/- 107 ng/m3. After 8000 Monte Carlo simulations, the cancer risk resulting from exposure to PAHs was found to be approximately 1.05 x 10(-4). A multivariate analysis was applied to identify the potential sources, and the results showed that, in addition to vehicle exhaust, coal combustion and cooking fumes were also another two important contributors to personal PAH exposure. The diagnostic ratios of PAH compounds agree with the source apportionment results derived from principal component analysis. PMID:25076537

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

    PubMed Central

    ZHU, XIANLEI; FAN, ZHIHUA (TINA); WU, XIANGMEI; JUNG, KYUNG HWA; OHMAN-STRICKLAND, PAMELA; BONANNO, LINDA J.; LIOY, PAUL J.

    2014-01-01

    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

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

    PubMed

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

    2013-06-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2011-11-01

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

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

    PubMed

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

    2014-07-15

    PAHs in the Great Lakes basin are of concern due to their toxicity and persistence in bottom sediments. Their nitro derivatives, nitro-PAHs (NPAHs), which can have stronger carcinogenic and mutagenic activity than parent PAHs, may follow similar transport routes and also are accumulated in sediments. Limited information exists regarding the current distribution, trends and loadings of these compounds, especially NPAHs, in Lake Michigan sediments. This study characterizes PAHs, NPAHs, and biomarkers steranes and hopanes in surface sediments collected at 24 offshore sites in southern Lake Michigan. The ?PAH14 (sum of 14 compounds) ranged from 213 to 1,291 ng/g dry weight (dw) across the sites, levels that are 2 to 10 times lower than those reported 20 to 30 years earlier. Compared to consensus-based sediment quality guidelines, PAH concentrations suggest very low risk to benthic organisms. The ?NPAH5 concentration ranged from 2.9 to 18.6 ng/g dw, and included carcinogenic compounds 1-nitropyrene and 6-nitrochrysene. ?Sterane6 and ?Hopane5 concentrations ranged from 6.2 to 36 and 98 to 355 ng/g dw, respectively. Based on these concentrations, Lake Michigan is approximately receiving 11, 0.16, 0.25 and 3.6 metrictons per year (t/yr) of ?PAH14, ?NPAH5, ?Sterane6 and ?Hopane5, respectively. Maps of OC-adjusted concentrations display that concentrations decline with increasing off-shore distance. The major sources of PAHs and NPAHs are pyrogenic in nature, based on diagnostic ratios. Using chemical mass balance models, sources were apportioned to emissions from diesel engines (56 18%), coal power plants (27 14%), coal-tar pavement sealants (16 11%), and coke ovens (7 12%). The biomarkers identify a combination of petrogenic and biogenic sources, with the southern end of the lake more impacted by petroleum. This first report of NPAH levels in sediments of Lake Michigan reveals several carcinogenic compounds at modest concentrations, and a need for further work to assess potential risks to aquatic organisms. PMID:24784742

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

    PubMed Central

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

    2014-01-01

    PAHs in the Great Lakes basin are of concern due to their toxicity and persistence in bottom sediments. Their nitro derivatives, nitro-PAHs (NPAHs), which can have stronger carcinogenic and mutagenic activity than parent PAHs, may follow similar transport routes and also are accumulated in sediments. Limited information exists regarding the current distribution, trends and loadings of these compounds, especially NPAHs, in Lake Michigan sediments. This study characterizes PAHs, NPAHs, and biomarkers steranes and hopanes in surface sediments collected at 24 offshore sites in southern Lake Michigan. The ΣPAH14 (sum of 14 compounds) ranged from 213 to 1291 ng/g dry weight (dw) across the sites, levels that are 2 to 10 times lower than those reported 20 to 30 years earlier. Compared to consensus-based sediment quality guidelines, PAH concentrations suggest very low risk to benthic organisms. The ΣNPAH5 concentration ranged from 2.9 to 18.6 ng/g dw, and included carcinogenic compounds 1-nitropyrene and 6-nitrochrysene. ΣSterane6 and ΣHopane5 concentrations ranged from 6.2 to 36 and 98 to 355 ng/g dw, respectively. Based on these concentrations, Lake Michigan is approximately receiving 11, 0.16, 0.25 and 3.6 metric tons per year (t/yr) of ΣPAH14, ΣNPAH5, ΣSterane6 and ΣHopane5, respectively. Maps of OC-adjusted concentrations display that concentrations decline with increasing off-shore distance. The major sources of PAHs and NPAHs are pyrogenic in nature, based on diagnostic ratios. Using chemical mass balance models, sources were apportioned to emissions from diesel engines (56±18%), coal power plants (27±14%), coal-tar pavement sealants (16±11%), and coke ovens (7±12%). The biomarkers identify a combination of petrogenic and biogenic sources, with the southern end of the lake more impacted by petroleum. This first report of NPAHs levels in sediments of Lake Michigan reveals several carcinogenic compounds at modest concentrations, and a need for further work to assess potential risks to aquatic organisms. PMID:24784742

  17. Urinary Nucleic Acid TSPAN13-to-S100A9 Ratio as a Diagnostic Marker in Prostate Cancer.

    PubMed

    Yan, Chunri; Kim, Ye-Hwan; Kang, Ho Won; Seo, Sung Phil; Jeong, Pildu; Lee, Il-Seok; Kim, Dongho; Kim, Jung Min; Choi, Yung Hyun; Moon, Sung-Kwon; Yun, Seok Joong; Kim, Wun-Jae

    2015-12-01

    The potential use of urinary nucleic acids as diagnostic markers in prostate cancer (PCa) was evaluated. Ninety-five urine samples and 234 prostate tissue samples from patients with PCa and benign prostatic hyperplasia (BPH) were analyzed. Micro-array analysis was used to identify candidate genes, which were verified by the two-gene expression ratio and validated in tissue mRNA and urinary nucleic acid cohorts. Real-time quantitative polymerase chain reaction (qPCR) was used to measure urinary nucleic acid levels and tissue mRNA expression. The TSPAN13-to-S100A9 ratio was selected to determine the diagnostic value of urinary nucleic acids in PCa (P = 0.037) and shown to be significantly higher in PCa than in BPH in the mRNA and nucleic acid cohort analyses (P < 0.001 and P = 0.013, respectively). Receiver operating characteristic (ROC) analysis showed that the area under the ROC curve was 0.898 and 0.676 in tissue mRNA cohort and urinary nucleic acid cohort, respectively. The TSPAN13-to-S100A9 ratio showed a strong potential as a diagnostic marker for PCa. The present results suggest that the analysis of urine supernatant can be used as a simple diagnostic method for PCa that can be adapted to the clinical setting in the future. PMID:26713053

  18. Urinary Nucleic Acid TSPAN13-to-S100A9 Ratio as a Diagnostic Marker in Prostate Cancer

    PubMed Central

    Seo, Sung Phil; Jeong, Pildu; Lee, Il-Seok; Kim, Dongho; Kim, Jung Min

    2015-01-01

    The potential use of urinary nucleic acids as diagnostic markers in prostate cancer (PCa) was evaluated. Ninety-five urine samples and 234 prostate tissue samples from patients with PCa and benign prostatic hyperplasia (BPH) were analyzed. Micro-array analysis was used to identify candidate genes, which were verified by the two-gene expression ratio and validated in tissue mRNA and urinary nucleic acid cohorts. Real-time quantitative polymerase chain reaction (qPCR) was used to measure urinary nucleic acid levels and tissue mRNA expression. The TSPAN13-to-S100A9 ratio was selected to determine the diagnostic value of urinary nucleic acids in PCa (P = 0.037) and shown to be significantly higher in PCa than in BPH in the mRNA and nucleic acid cohort analyses (P < 0.001 and P = 0.013, respectively). Receiver operating characteristic (ROC) analysis showed that the area under the ROC curve was 0.898 and 0.676 in tissue mRNA cohort and urinary nucleic acid cohort, respectively. The TSPAN13-to-S100A9 ratio showed a strong potential as a diagnostic marker for PCa. The present results suggest that the analysis of urine supernatant can be used as a simple diagnostic method for PCa that can be adapted to the clinical setting in the future. PMID:26713053

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

  20. Ratio

    NASA Astrophysics Data System (ADS)

    Webster, Nathan A. S.; Pownceby, Mark I.; Madsen, Ian C.; Studer, Andrew J.; Manuel, James R.; Kimpton, Justin A.

    2014-12-01

    Effects of basicity, B (CaO:SiO2 ratio) on the thermal range, concentration, and formation mechanisms of silico-ferrite of calcium and aluminum (SFCA) and SFCA-I iron ore sinter bonding phases have been investigated using an in situ synchrotron X-ray diffraction-based methodology with subsequent Rietveld refinement-based quantitative phase analysis. SFCA and SFCA-I phases are the key bonding materials in iron ore sinter, and improved understanding of the effects of processing parameters such as basicity on their formation and decomposition may assist in improving efficiency of industrial iron ore sintering operations. Increasing basicity significantly increased the thermal range of SFCA-I, from 1363 K to 1533 K (1090 °C to 1260 °C) for a mixture with B = 2.48, to ~1339 K to 1535 K (1066 °C to 1262 °C) for a mixture with B = 3.96, and to ~1323 K to 1593 K (1050 °C to 1320 °C) at B = 4.94. Increasing basicity also increased the amount of SFCA-I formed, from 18 wt pct for the mixture with B = 2.48 to 25 wt pct for the B = 4.94 mixture. Higher basicity of the starting sinter mixture will, therefore, increase the amount of SFCA-I, considered to be more desirable of the two phases. Basicity did not appear to significantly influence the formation mechanism of SFCA-I. It did, however, affect the formation mechanism of SFCA, with the decomposition of SFCA-I coinciding with the formation of a significant amount of additional SFCA in the B = 2.48 and 3.96 mixtures but only a minor amount in the highest basicity mixture. In situ neutron diffraction enabled characterization of the behavior of magnetite after melting of SFCA produced a magnetite plus melt phase assemblage.

  1. Distribution and bioaccumulation of PAHs in the UNESCO protected natural reserve of Urdaibai, Bay of Biscay.

    PubMed

    Cortazar, E; Bartolomé, L; Arrasate, S; Usobiaga, A; Raposo, J C; Zuloaga, O; Etxebarria, N

    2008-08-01

    Along 10 campaigns, from June 2002 to September 2004, the concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) were measured in sediments and oysters (Crassostrea sp.) taken from four sites in the Unesco protected natural reserve of Urdaibai (Basque Country, Bay of Biscay). Total PAH concentration ranged from 0.7 to 140 microg kg(-1) (dw) in the case of sediments, and from 300 to 1400 microg kg(-1) (dw) in the case of oysters. During this study, the coast of the Bay of Biscay was severely affected by the Prestige oil spill (November 2002). Presumably, as a consequence of this accident, both spatial and temporal variations of the PAHs, as well as the sources of the PAHs were affected by the oil spill, and this effect was observed in the total concentrations and, especially, in several diagnostic ratios and in multivariate data analysis. Finally, both BAF (bioaccumulation factor) and BSAF (biota-sediment accumulation factor) parameters were calculated to conclude that particulate matter seems to be the most favourable uptake pathway of PAHs in oysters from this estuary. PMID:18597814

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

  3. A multivariate receptor modeling study of air-borne particulate PAHs: Regional contributions in a roadside environment.

    PubMed

    Kim, Bong Mann; Lee, Seung-Bok; Kim, Jin Young; Kim, Sunwha; Seo, Jihoon; Bae, Gwi-Nam; Lee, Ji Yi

    2016-02-01

    Understanding the geographic source contributions by particulate polycyclic aromatic hydrocarbons (PAHs) is important for the Korean peninsula due to its downwind location from source areas. Regional influence of particulate PAHs was previously identified using diagnostic ratios applied to mobile source dominated roadside sampling data (Kim etal., 2012b). However, no study has yet been conducted to quantify the regional source contributions. We applied a multivariate receptor modeling tool to identify and quantify the regional source contributions to particulate PAHs in Seoul. Sampling of roadside particulate PAHs was conducted in Seoul, Korea for four years between May 2005 and April 2009, and data analysis was performed with a new multivariate receptor model, Solver for Mixture Problem (SMP). The SMP model identified two sources, local mobile source and transported regional source, and quantified their source contributions. Analysis of the particulate PAHs data reveals three types of episodic periods: a high regional source contribution period with one case, a high mobile source contribution period with three cases, and a normal contribution period with eight cases. Four-year average particulate PAHs source contributions from the two sources are 4.6ngm(-3) and 10.7ngm(-3) for regional and mobile sources, respectively and equivalent to 30% and 70% of the total estimated contribution from each of these sources. PMID:26473551

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

    SciTech Connect

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

    2011-12-01

    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.

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

    PubMed

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

    2015-04-01

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

  6. Diurnal and nocturnal variations of PAHs in the Lhasa atmosphere, Tibetan Plateau: Implication for local sources and the impact of atmospheric degradation processing

    NASA Astrophysics Data System (ADS)

    Liu, Junwen; Li, Jun; Lin, Tian; Liu, Di; Xu, Yue; Chaemfa, Chakra; Qi, Shihua; Liu, Fobang; Zhang, Gan

    2013-04-01

    Due to the unique characteristics, such as intensive radiation, high altitude and low humidity, plateau climate importantly affects the airborne organic contaminants' behavior in the environment. In this study, USEPA priority polycyclic aromatic hydrocarbons (PAHs) and benzo[e]pyrene were detected in the air samples collected at two suburban sites in Lhasa city. The total concentrations of USEPA priority fifteen PAHs (except naphthalene) in the particulate phase ranged from 4.4 to 60 ng/m3, while in the gas phase from 79 to 350 ng/m3. Integrated results of the multiple diagnostic ratios indicated that the major potential sources of PAHs in Lhasa city were local incomplete combustion of wood and cow dung cake. Particulate and gaseous PAH levels in this study displayed two clear and different diurnal and nocturnal concentration patterns, however, no distinct diurnal and nocturnal variation was observed for the total suspended particles (TSP) concentrations. No significant correlation was found between TSP concentrations and particle-bound PAHs, meaning physicochemical processes play an important role in diurnal and nocturnal variations of PAHs in the atmosphere except emission sources in this study. Based on the diurnal and nocturnal changes of the percentage of particulate phase PAHs in total PAHs, it suggested that gas-particle partitioning driven by temperature makes a great contribution to the variations of PAHs concentrations. The most susceptible to transformation between gas and particle phase chemicals are PHE, ANT, FLA, PYR, BaA and CHR. In addition, our observation suggested that atmospheric reaction and photolytic degradation also exert an important impact on the variations of PAHs in both phases in the atmosphere of Lhasa city.

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

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

  8. O2/CO2 emission ratios as a diagnostic for source identification?

    NASA Astrophysics Data System (ADS)

    Steinbach, J.; Gerbig, C.

    2009-04-01

    High-precision measurements of atmospheric oxygen play an increasingly important role in our understanding of the global carbon cycle. In combination with CO2-measurements, they allow the partitioning of global oceanic and terrestrial sinks of anthropogenic CO2. In addition, local source/sink patterns can be identified from the combination of O2 and CO2-signals since different combustion processes have different oxidative ratios (OR= -O2/CO2). Therefore, atmospheric O2 measurements can help to distinguish between industrial and terrestrial influences on observed CO2 variations. In addition, the oxidative ratios for fossil fuel combustion vary for different types of fuels, from 1.95 for natural gas over 1.44 for liquid fuels to 1.17 for coal; hence oxidative ratios can also be used for distinguishing different fossil fuel sources. This study aims to create a detailed map of the global O2 uptake associated with the combustion of fossil fuels. For this, we combine the oxidative ratios for diverse fossil fuel types with a fossil fuel inventory, created using the EDGAR emission database in combination with BP fossil fuel consumption statistics on oil, gas and coal. This information on spatial patterns of O2/CO2 emission ratios together with continuous measurements of O2 and CO2 will be useful for separating different emission sources and thus for better interpretation of regional CO2 budgets, but it will also be useful for the attribution of other pollutants in the atmosphere to the different source types and regions.

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

    CO observations in active galactic nuclei and starbursts reveal high kinetic temperatures. Those environments are thought to be very turbulent due to dynamic phenomena, such as outflows and high supernova rates. We investigate the effect of mechanical heating on atomic fine-structure and molecular lines and on their ratios. We try to use those ratios as a diagnostic to constrain the amount of mechanical heating in an object and also study its significance on estimating the H2 mass. Equilibrium photodissociation models (PDRs hereafter) were used to compute the thermal and chemical balance for the clouds. The equilibria were solved for numerically using the optimized version of the Leiden PDR-XDR code. Large velocity-gradient calculations were done as post-processing on the output of the PDR models using RADEX. High-J CO line ratios are very sensitive to mechanical heating (?mech hereafter). These emission becomes at least one order of magnitude brighter in clouds with n ~ 105 cm-3 and a star formation rate of 1 M? yr-1 (corresponding to ?mech = 2 10-19 erg cm-3 s-1). The emission of low-J CO lines is not as sensitive to ?mech, but they do become brighter in response to ?mech. Generally, for all of the lines we considered, ?mech increases excitation temperatures and decreases the optical depth at the line centre. Hence line ratios are also affected, strongly in some cases. Ratios involving HCN are a good diagnostic for ?mech, where the HCN(1-0)/CO(1-0) increases from 0.06 to 0.25, and the HCN(1-0)/HCO+(1-0) increase from 0.15 to 0.5 for amounts of ?mech that are equivalent to 5% of the surface heating rate. Both ratios increase to more than 1 for higher ?mech, as opposed to being much less than unity in pure PDRs. The first major conclusion is that low-J to high-J intensity ratios will yield a good estimate of the mechanical heating rate (as opposed to only low-J ratios). The second one is that the mechanical heating rate should be taken into account when determing AV or, equivalently, NH, and consequently the cloud mass. Ignoring ?mech will also lead to large errors in density and radiation field estimates. Appendices are available in electronic form at http://www.aanda.orgThe data used to generate all the grids are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/574/A127

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

    PubMed

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

    2014-11-01

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

  11. Diagnostic accuracy of cardiothoracic ratio on admission chest radiography to detect left or right ventricular systolic dysfunction: a retrospective study

    PubMed Central

    Chana, Harmeet S; Martin, Claire A; Cakebread, Holly E; Adjei, Felicia D

    2015-01-01

    Objectives To determine the diagnostic accuracy of the cardiothoracic ratio on postero-anterior or antero-posterior chest radiographs in predicting left ventricular or right ventricular dysfunction on echocardiography in an inpatient population. Design Retrospective study. Setting Two secondary care hospitals in the United Kingdom. Participants Four hundred consecutive inpatient echocardiograms were screened for inclusion along with chest radiographs (both postero-anterior and antero-posterior). The cardiothoracic ratio was calculated from chest radiographs along with quantitative and qualitative measures of left ventricular or right ventricular dysfunction on echocardiography. Main outcome measures Sensitivity and specificity of cardiothoracic ratio across a range of values to detect moderate/severe left ventricular and/or right ventricular dysfunction on echocardiography. Results Overall, 272 records met inclusion criteria. The prevalence of left ventricular/right ventricular dysfunction on echocardiography was 26% in an inpatient population with high clinical suspicion of cardiac disease referred for echocardiography. Over a range of cardiothoracic ratio values on postero-anterior films, a value of >0.55 yielded the best sensitivity (62.5%) and specificity (76.5%) for diagnosing left ventricular/right ventricular impairment (positive likelihood ratio 2.56), with a positive predictive value of 29.5%. Cardiothoracic ratio on antero-posterior film was not predictive of left ventricular/right ventricular impairment on echocardiography. Conclusions In conclusion, in the context of an acute admission, cardiothoracic ratio measured on postero-anterior or antero-posterior films has limited value in detecting moderate left ventricular and/or right ventricular systolic dysfunction. Previously established absolute values may be unreliable by modern standards. PMID:26152673

  12. Diagnostic Accuracy of Neutrophil/Lymphocyte Ratio, Red Cell Distribution Width and Platelet Distribution Width in Ovarian Torsion.

    PubMed

    Yilmaz, M; Cimilli, G; Saritemur, M; Demircan, F; Isaoglu, U; Kisaoglu, A; Emet, M

    2016-02-01

    The main aim of this diagnostic case-control study of 136 patients with ovarian cysts (44 patients with ovarian torsion and 92 controls) was to determine the diagnostic value of haematologic inflammatory markers (neutrophil/lymphocyte ratio [NLR], red cell distribution width [RDW] and platelet distribution width [PDW]) for torsioned ovarian cysts. The presence of a torsioned ovarian cyst was identified by a 1.18-fold increase in the NLR (95%CI: 1.04-1.34, P = 0.009), a 1.22-fold increase in the RDW (95%CI: 1.04-1.43, P = 0.023) and a 1.93-fold increase in the PDW (95%CI: 1.19-3.14, P = 0.007). The NLR was the best predictor of a torsioned ovarian cyst (AUC: 0.74; 95% CI: 0.68-0.83). When an NLR cut-off value of 2.44 was used to determine ovarian torsion, the sensitivity, specificity, + LR and -LR were 70.5%, 70.7%, 2.40 and 0.42, respectively. In conclusion, the NLR may have diagnostic and prognostic value in determining torsioned ovarian cysts. PMID:26467739

  13. Implications of contamination and surface area ratios for Langmuir probe diagnostics on CubeSats

    NASA Astrophysics Data System (ADS)

    Suresh, P.; Swenson, C.

    2009-12-01

    Theories describing the current collected by a biased probe under various conditions are necessary for such observation to be used to accurately determine plasma properties. Langmuir probes are routinely used on spacecraft to measure plasma parameters such as density, temperature, and vehicle charging. The collected current is a function of the potential between the surrounding plasma and probe surface. There have been both observations of and concepts for unaccounted variations of this potential which limit the application of Langmuir probe theory for determining plasma properties. These variations occur due to spatial variations of the work function across the probe surface due to non-uniformity of the crystalline surface properties and surface contamination of the probe. Currently we do not have theoretical expressions which consider these factors as first principles in their derivation. In the event of these surface potential variations, the analysis of the plasma using the currently available theories of the Langmuir probe yield erroneous results. We present a theory which models the current as a function of the surface potential variations. Another consideration for Langmuir probes on CubeSats is the ratio of the probe area to the return current collection area. If the area ratio is unfavorable this can also lead to erroneous results in the interpretation of observations. A mathematical formulation of the current collected by the probe for contaminated surfaces is presented and compared with data from a Langmuir probe flown on a sounding rocket mission. The implications of using Langmuir probes on CubeSats given the engineering limitations of probe cleanliness and area ratios are reviewed.

  14. [Altitudinal Gradient Distribution and Source Analysis of PAHs Content of Topsoil in Jinfo Mountain, Chongqing].

    PubMed

    Shi, Yang; Sun, Yu-chuan; Liang, Zuo-bing; Ren, Kun; Yuan, Dao-xian

    2015-04-01

    The condensation effect has made high mountains the storage vault of durable organic pollutants. This research measured the content and constitutes of polycyclic aromatic hydrocarbons (PAHs) in 10 topsoil samples collected at different altitudes from the south slope of Chongqing Jinfo Mountain by gas chromatograph-mass spectrometer (GC/MC). And the pollution source of PAHs was analyzed by ratio method and principal component regression. The ecological risk of PAHs was evaluated using BaP toxic equivlants (TEQ(BaP)) The results showed that the concentrations of 16 priority PAHs in topsoil ranged from 240-2 121 ng x g(-1). The average value of PAHs was 849 ng x g(-1), and 2 to 3-ring PAHs were the dominant compounds. The concentrations of 7 carcinogenic PAHs accounted for 17.8% of total PAHs averagely. In the research area, various-ring PAHs and gross PAHs increased with the rise of altitude. The increase of low-ring PAHs was most obvious, and the volatility of high-ring PAHs was relatively high. But the ratio of different-ring PAHs in gross PAHs showed no regularity with the rise of altitude. The PAHs of soil in the research area mainly came from the oil sources, oil products, and combustion sources of coal and biomass. In the research area, the soil has been polluted to a certain extent, but the toxicity risk is relatively low. PMID:26164921

  15. Characterization, ecological risk assessment and source diagnostics of polycyclic aromatic hydrocarbons in water column of the Yellow River Delta, one of the most plenty biodiversity zones in the world.

    PubMed

    Wang, Lili; Yang, Zhifeng; Niu, Junfeng; Wang, Jingyi

    2009-09-30

    As one of the most active regions of land-ocean interaction among the large river deltas in the world, the Yellow River Delta (YRD) gains increasing concern on its ecological and environmental conditions. However, few studies on polycyclic aromatic hydrocarbons (PAHs) have been reported for this area. In this study, the distribution characteristics, probabilistic risk and possible sources of PAHs were investigated in the water column of the YRD. The PAH concentrations were found to be at relatively low or medium levels (121.3 ng L(-1) in water and 209.1n g g(-1) in suspended particulate matter (SPM) on average), and the result of probability risk assessment additionally elucidated low PAH ecological risk in the YRD. The PAH composition showed that low and moderate molecular PAHs were the major species in water phase, whereas the SPM showed a different proportion of each PAH composition. An interesting result was found that low-ring PAHs and salinity in this land-ocean interaction area had a positive relationship (R=0.609). For PAH source identification, both diagnostic ratios of selected PAHs and principal component analysis (PCA) with multiple linear regression (MLR) analysis were studied, suggesting mixed sources of pyrogenic and petrogenic deriving PAHs in the YRD. PMID:19398155

  16. Characterization and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in urban atmospheric Particulate of Tehran, Iran.

    PubMed

    Hoseini, Mohammad; Yunesian, Masud; Nabizadeh, Ramin; Yaghmaeian, Kamyar; Ahmadkhaniha, Reza; Rastkari, Noushin; Parmy, Saeid; Faridi, Sasan; Rafiee, Ata; Naddafi, Kazem

    2016-01-01

    In this study, atmospheric concentrations of particulate-bound polycyclic aromatic hydrocarbons (PAHs) in Tehran megacity were determined to investigate the concentration, distribution, and sources of PAHs in PM10. The health risk from exposure to airborne BaPeq through inhalation pathway was also assessed. Toxic equivalency factors (TEFs) approach was used for quantitative risk estimate, and incremental lifetime cancer risk (ILCR) was calculated. PM10 samples were collected at ten sampling locations during the summer 2013 and winter 2014 by using two independent methods of field sampling. The PM10 concentration in winter (89.55??15.56?gm(-3)) was 1.19 times higher than that in summer (75.42??14.93?gm(-3)). Sixteen PAHs were measured with the total average concentrations of PAHs ranged from 56.98??15.91 to 110.35??57.31ngm(-3) in summer and from 125.87??79.02 to 171.25??73.94ngm(-3) in winter which were much higher than concentrations measured in most similar studies conducted around the world. Molecular diagnostic ratios were used to identify PAH emission sources. The results indicated that gasoline-driven vehicles are the major sources of PAHs in the study area. Risk analysis showed that the mean and 90% probability estimated inhalation ILCRs were 7.85??10(-6) and 16.78??10(-6), respectively. Results of a sensitivity analysis indicated that BaP concentration and cancer slope factor (CSF) contributed most to effect on ILCR mean. PMID:26400241

  17. Diagnostic Accuracy of Urine Protein/Creatinine Ratio Is Influenced by Urine Concentration

    PubMed Central

    Yang, Chih-Yu; Chen, Fu-An; Chen, Chun-Fan; Liu, Wen-Sheng; Shih, Chia-Jen; Ou, Shuo-Ming; Yang, Wu-Chang; Lin, Chih-Ching; Yang, An-Hang

    2015-01-01

    Background The usage of urine protein/creatinine ratio to estimate daily urine protein excretion is prevalent, but relatively little attention has been paid to the influence of urine concentration and its impact on test accuracy. We took advantage of 24-hour urine collection to examine both urine protein/creatinine ratio (UPCR) and daily urine protein excretion, with the latter as the reference standard. Specific gravity from a concomitant urinalysis of the same urine sample was used to indicate the urine concentration. Methods During 2010 to 2014, there were 540 adequately collected 24h urine samples with protein concentration, creatinine concentration, total volume, and a concomitant urinalysis of the same sample. Variables associated with an accurate UPCR estimation were determined by multivariate linear regression analysis. Receiver operating characteristic (ROC) curves were generated to determine the discriminant cut-off values of urine creatinine concentration for predicting an accurate UPCR estimation in either dilute or concentrated urine samples. Results Our findings indicated that for dilute urine, as indicated by a low urine specific gravity, UPCR is more likely to overestimate the actual daily urine protein excretion. On the contrary, UPCR of concentrated urine is more likely to result in an underestimation. By ROC curve analysis, the best cut-off value of urine creatinine concentration for predicting overestimation by UPCR of dilute urine (specific gravity ≦ 1.005) was ≦ 38.8 mg/dL, whereas the best cut-off values of urine creatinine for predicting underestimation by UPCR of thick urine were ≧ 63.6 mg/dL (specific gravity ≧ 1.015), ≧ 62.1 mg/dL (specific gravity ≧ 1.020), ≧ 61.5 mg/dL (specific gravity ≧ 1.025), respectively. We also compared distribution patterns of urine creatinine concentration of 24h urine cohort with a concurrent spot urine cohort and found that the underestimation might be more profound in single voided samples. Conclusions The UPCR in samples with low or high specific gravity is more likely to overestimate or underestimate actual daily urine protein amount, respectively, especially in a dilute urine sample with its creatinine below 38.8 mg/dL or a concentrated sample with its creatinine above 61.5 mg/dL. In particular, UPCR results should be interpreted with caution in cases that involve dilute urine samples because its overestimation may lead to an erroneous diagnosis of proteinuric renal disease or an incorrect staging of chronic kidney disease. PMID:26353117

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

    PubMed

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

    2014-09-01

    Dioxin-Responsive Chemical-Activated LUciferase gene eXpression assay (DR-CALUX) was applied to assess the total toxic activity of the mixture of PAHs and related compounds as well as dioxin-related compounds in road dust from urban areas of Hanoi, Vietnam. Road dust from Hanoi contained significantly higher DR-CALUX activities (3 to 39, mean 20 ng CALUX-TEQ/g dw) than those from a rural site (2 to 13, mean 5 ng CALUX-TEQ/g dw). The total concentrations of 24 major PAHs (Σ24PAHs) in urban road dust (0.1 to 5.5, mean 2.5 μg/g dw) were also 6 times higher than those in rural road dust (0.08 to 1.5, mean 0.4 μg/g dw). Diagnostic ratios of PAHs indicated vehicular engine combustion as the major PAH emission source in both sites. PAHs accounted for 0.8 to 60% (mean 10%) and 2 to 76% (mean 20%) of the measured CALUX-TEQs in road dust for Hanoi the rural site, respectively. Benzo[b]-/benzo[k]fluoranthenes were the major TEQ contributors among PAHs, whereas DRCs contributed <0.1% to CALUX-TEQs for both rural and urban sites. These results suggest TEQ contribution of other aryl hydrocarbon receptor agonists in road dust. Significant PAH concentrations in urban dust indicated high mutagenic and carcinogenic potencies. Estimated results of incremental life time cancer risk (ILCR) indicated that Vietnamese populations, especially those in urban areas such as Hanoi, are potentially exposed to high cancer risk via both dust ingestion and dermal contact. This is the first study on the exposure risk of AhR agonists, including PAHs and DRCs, in urban road dust from a developing country using a combined bio-chemical analytical approach. PMID:24522011

  19. Neutron spectroscopy as a fuel ion ratio diagnostic: Lessons from JET and prospects for ITERa)

    NASA Astrophysics Data System (ADS)

    Ericsson, G.; Conroy, S.; Gatu Johnson, M.; Andersson Sundn, E.; Cecconello, M.; Eriksson, J.; Hellesen, C.; Sangaroon, S.; Weiszflog, M.; Jet Efda Contributors

    2010-10-01

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

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

    SciTech Connect

    Ericsson, G.; Conroy, S.; Gatu Johnson, M.; Andersson Sunden, E.; Cecconello, M.; Eriksson, J.; Hellesen, C.; Sangaroon, S.; Weiszflog, M.; Collaboration: JET EFDA Contributors

    2010-10-15

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

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

    PubMed Central

    Sower, GJ; Anderson, K.A.

    2014-01-01

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

  2. Infrared spectra of interstellar deuteronated PAHs

    NASA Astrophysics Data System (ADS)

    Buragohain, Mridusmita; Pathak, Amit; Sarre, Peter

    2015-08-01

    Polycyclic Aromatic Hydrocarbon (PAH) molecules have emerged as a potential constituent of the ISM that emit strong features at 3.3, 6.2, 7.7, 8.6, 11.2 and 12.7 μm with weaker and blended features in the 3-20μm region. These features are proposed to arise from the vibrational relaxation of PAH molecules on absorption of background UV photons (Tielens 2008). These IR features have been observed towards almost all types of astronomical objects; say H II regions, photodissociation regions, reflection nebulae, planetary nebulae, young star forming regions, external galaxies, etc. A recent observation has proposed that interstellar PAHs are major reservoir for interstellar deuterium (D) (Peeters et al. 2004). According to the `deuterium depletion model' as suggested by Draine (2006), some of the Ds formed in the big bang are depleted in PAHs, which can account for the present value of D/H in the ISM. Hence, study of deuterated PAHs (PADs) is essential in order to measure D/H in the ISM.In this work, we consider another probable category of the large PAH family, i.e. Deuteronated PAHs (DPAH+). Onaka et al. have proposed a D/H ratio which is an order of magnitude smaller than the proposed value of D/H by Draine suggesting that if Ds are depleted in PAHs, they might be accommodated in large PAHs (Onaka et al. 2014). This work reports a `Density Functional Theory' calculation of large deuteronated PAHs (coronene, ovalene, circumcoronene and circumcircumcoronene) to determine the expected region of emission features and to find a D/H ratio that is comparable to the observational results. We present a detailed analysis of the IR spectra of these molecules and discuss the possible astrophysical implications.ReferencesDraine B. T. 2006, in ASP Conf. Ser. 348, Proc. Astrophysics in the Far Ultraviolet: Five Years of Discovery with FUSE, ed. G. Sonneborn, H. Moos, B-G Andersson (San Francisco, CA:ASP) 58Onaka T., Mori T. I., Sakon I., Ohsawa R., Kaneda H., Okada Y., Tanaka M., 2014, ApJ,780,114Peeters E., Allamandola L. J., Bauschlicher C. W., Jr., Hudgins D. M., Sandford S. A., Tielens A. G. G. M., 2004, ApJ, 604, 252Tielens A. G. G. M. 2008, ARA&A, 46, 289

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

    PubMed

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

    2014-10-15

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

  4. VIMOS integral field spectroscopy of blue compact galaxies. I. Morphological properties, diagnostic emission-line ratios, and kinematics

    NASA Astrophysics Data System (ADS)

    Cairós, L. M.; Caon, N.; Weilbacher, P. M.

    2015-05-01

    Context. Blue compact galaxies (BCG) are gas-rich, low-luminosity, low-metallicity systems that undergo a violent burst of star formation. These galaxies offer us a unique opportunity to investigate collective star formation and its effects on galaxy evolution in a relatively simple environment. Spatially resolved spectrophotometric studies of BCGs are essential for a better understanding of the role of starburst-driven feedback processes on the kinematical and chemical evolution of low-mass galaxies near and far. Aims: We carry out an integral field spectroscopic study of a sample of BCGs, with the aim of probing the morphology, kinematics, dust extinction, and excitation mechanisms of their warm interstellar medium. Methods: Eight BCGs were observed with the VIMOS integral field unit at the Very Large Telescope using blue and orange grisms in high-resolution mode. At a spatial sampling of 0''&dotbelow;67 per spaxel, we covered about 30″ × 30″ on the sky, with a wavelength range of 4150...7400 Å. Emission lines were fitted with a single Gaussian profile to measure their wavelength, flux, and width. From these data we built two-dimensional maps of the continuum and the most prominent emission-lines, as well as diagnostic line ratios, extinction, and kinematic maps. Results: An atlas has been produced with the following: emission-line fluxes and continuum emission; ionization, interstellar extinction, and electron density maps from line ratios; velocity and velocity dispersion fields. From integrated spectroscopy, it includes tables of the extinction corrected line fluxes and equivalent widths, diagnostic-line ratios, physical parameters, and the abundances for the brightest star-forming knots and for the whole galaxy. Based on observations made with ESO Telescopes at the Paranal Observatory under program ID 079.B-0445.The reduced datacubes and their error maps (FITS files) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/577/A21

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

    NASA Astrophysics Data System (ADS)

    Topal, Selcuk; Bureau, Martin; Davis, Timothy A.; Young, Lisa; Krips, Melanie

    2015-01-01

    We present interferometric observations of a multitude of CO lines [12CO(1-0), 12CO(2-1), 13CO(1-0) and 13CO(2-1)] and dense gas tracers [HCN(1-0), HCO+(1-0), HNC(1-0) and HNCO(4-3)] in two nearby edge-on lenticular galaxies, NGC 4710 and NGC 5866. The position-velocity diagrams of both galaxies are X-shaped, revealing that the galaxies are barred, with most of the gas concentrated in a nuclear disc and an inner ring in each galaxy. Relatively tenuous (CO) molecular gas is present in both kinematic components, while dense gas is generally only detected in the nuclear discs. We probe the physical conditions of a two-component molecular interstellar medium in each galaxy and each kinematic component by using molecular line ratio diagnostics in three complementary ways. First, we measure the ratios of the position-velocity diagrams of different lines, second we measure the ratios of the integrated line intensities as a function of projected position in each kinematic component taken separately, and third we model the line ratios using a non-local thermodynamic equilibrium radiative transfer code characterising the kinetic temperature, volume density and column density of the molecular gas. Overall, the nuclear discs appear to have a tenuous molecular gas component that is hotter and optically thinner than that in the inner rings, with a larger dense gas fraction, suggesting more dense clumps immersed in a hotter more diffuse molecular medium. This is consistent with evidence that the physical conditions in the nuclear discs are similar to those in photo-dissociation regions, with intense UV radiation from young stars and few cosmic rays. A similar picture emerges when comparing the observed molecular line ratios with those of other galaxy types and spatially-resolved giant molecular clouds. While there are a number of similarities and differences, the physical conditions of the molecular gas in the nuclear discs of NGC 4710 and NGC 5866 appear intermediate between those of spiral galaxies and starbursts, with intense but not extreme star-formation activity, while the star formation in the inner rings is even milder.

  6. Characterization of PAHs and metals in indoor/outdoor PM10/PM2.5/PM1 in a retirement home and a school dormitory.

    PubMed

    Hassanvand, Mohammad Sadegh; Naddafi, Kazem; Faridi, Sasan; Nabizadeh, Ramin; Sowlat, Mohammad Hossein; Momeniha, Fatemeh; Gholampour, Akbar; Arhami, Mohammad; Kashani, Homa; Zare, Ahad; Niazi, Sadegh; Rastkari, Noushin; Nazmara, Shahrokh; Ghani, Maryam; Yunesian, Masud

    2015-09-15

    In the present work, we investigated the characteristics of polycyclic aromatic hydrocarbons (PAHs) and metal(loid)s in indoor/outdoor PM10, PM2.5, and PM1 in a retirement home and a school dormitory in Tehran from May 2012 to May 2013. The results indicated that the annual levels of indoor and outdoor PM10 and PM2.5 were much higher than the guidelines issued by the World Health Organization (WHO). The most abundant detected metal(loid)s in PM were Si, Fe, Zn, Al, and Pb. We found higher percentages of metal(loid)s in smaller size fractions of PM. Additionally, the results showed that the total PAHs (?PAHs) bound to PM were predominantly (83-88%) found in PM2.5, which can penetrate deep into the alveolar regions of the lungs. In general, carcinogenic PAHs accounted for 40-47% of the total PAHs concentrations; furthermore, the smaller the particle size, the higher the percentage of carcinogenic PAHs. The percentages of trace metal(loid)s and carcinogenic PAHs in PM2.5 mass were almost twice as high as those in PM10. This can most likely be responsible for the fact that PM2.5 can cause more adverse health effects than PM10 can. The average BaP-equivalent carcinogenic (BaP-TEQ) levels both indoors and outdoors considerably exceeded the maximum permissible risk level of 1 ng/m(3) of BaP. The enrichment factors and diagnostic ratios indicated that combustion-related anthropogenic sources, such as gasoline- and diesel-fueled vehicles as well as natural gas combustion, were the major sources of PAHs and trace metal(loid)s bound to PM. PMID:25958359

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

    PubMed

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

    2014-08-15

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

  8. Concentration, composition and sources of PAHs in the coastal sediments of the exclusive economic zone (EEZ) of Qatar, Arabian Gulf.

    PubMed

    Soliman, Y S; Al Ansari, E M S; Wade, T L

    2014-08-30

    Surface sediments were collected from sixteen locations in order to assess levels and sources of polycyclic aromatic hydrocarbons (PAHs) in sediments of Qatar exclusive economic zone (EEZ). Samples were analyzed for 16 parent PAHs, 18 alkyl homologs and for dibenzothiophenes. Total PAHs concentration (∑PAHs) ranged from 2.6 ng g(-1) to 1025 ng g(-1). The highest PAHs concentrations were in sediments in and adjacent to harbors. Alkylated PAHs predominated most of the sampling locations reaching up to 80% in offshore locations. Parent PAHs and parent high molecular weight PAHs dominated location adjacent to industrial activities and urban areas. The origin of PAHs sources to the sediments was elucidated using ternary plot, indices, and molecular ratios of specific compounds such as (Ant/Phe+Ant), (Flt/Flt+Pyr). PAHs inputs to most coastal sites consisted of mixture of petroleum and combustion derived sources. However, inputs to the offshore sediments were mainly of petroleum origin. PMID:24798421

  9. Laboratory Spectroscopy of PAHs

    NASA Astrophysics Data System (ADS)

    Pino, T.; Fraud, G.; Brchignac, Ph.; Bieske, E. J.; Schmidt, T. W.

    2014-02-01

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

  10. Anionic-nonionic mixed-surfactant-enhanced remediation of PAH-contaminated soil.

    PubMed

    Shi, Zhentian; Chen, Jiajun; Liu, Jianfei; Wang, Ning; Sun, Zheng; Wang, Xingwei

    2015-08-01

    Soil washing is an efficient remediation technique that enhances the solubility of polycyclic aromatic hydrocarbons (PAHs) in specific surfactant to remediate PAH-contaminated soil. This study evaluated the remediation efficiency of PAH-contaminated soil from a coke oven plant by comparing sodium dodecyl sulfate (SDS), sodium dodecylbenzene sulfonate (SDBS), and Triton X-100 (TX100), as well as TX100-SDS and TX100-SDBS mixed surfactants. Results showed that SDS-TX100 and SDBS-TX100 had synergistic effects on PAH solubilization when surfactant concentrations were above their critical micelle concentration. Competitive effects of the three solubilized PAHs (phenanthrene with three rings, fluoranthene with four rings, and benzo[a]pyrene with five rings) with a particular anionic-nonionic mixed surfactant were investigated. PAHs with more rings were found to slightly decrease the solubility in surfactant solution of PAHs with fewer rings, whereas PAHs with fewer rings promoted the solubility in surfactant solution of PAHs with more rings. The removal ratios of PAHs during the remediation of actual PAH-contaminated soil were best improved by the anionic-nonionic mixed surfactant TX100-SDS (9:1), followed by TX100-SDS (8:2), TX100-SDS (7:3), TX100-SDBS (7:3), TX100, SDBS, and SDS. Therefore, anionic-nonionic mixed surfactants can help improve the remediation performance of PAHs based on their application in tests of cleaning actual PAH-contaminated soil from a coke oven plant. PMID:26002358

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

    NASA Technical Reports Server (NTRS)

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

    2005-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

    In Naples, particulate matter PM10 associated with polycyclic aromatic hydrocarbons (PAHs) in ambient air were determined in urban background (NA01) and urban traffic (NA02) sites. The principal objective of the study was to determine the concentration and distribution of PAHs in PM10 for identification of their possible sources (through diagnostic ratio - DR and principal component analysis - PCA) and an estimation of the human health risk (from exposure to airborne TEQ). Airborne PM10 samples were collected on quartz filters using a Low Volume Sampler (LVS) for 24 h with seasonal samples (autumn, winter, spring and summer) of about 15 days each between October 2012 and July 2013. The PM10 mass was gravimetrically determined. The PM10 levels, in all seasons, were significantly higher (P < 0.001) in the urban-traffic site (NA02) than in the urban-background site (NA01). The filters were then extracted with dichloromethane using an ultrasonicator (SONICA) to perform a detailed characterization of 12 priority PAHs proposed by the USEPA, by gas chromatography-mass spectrometer (GC-MS) analysis. The concentration of Benzo[a]Pyrene, BaP (EU and National limit value: 1 ng m-3 in PM10), varied from 0.065 ng m-3 during autumn time to 0.872 ng m-3 in spring time (NA01) and from 0.120 ng m-3 during autumn time to 1.48 ng m-3 of winter time (NA02) with four overshoots. In NA02 the trend of Σ12 PAHs was comparable to NA01 but were observed higher values than NA01. In fact, the mean concentration of Σ12 PAHs, in urban-traffic site was generally 2 times greater than in urban-background site in all the campaigns. PAHs with 5 and 6 ring, many of which are suspected carcinogens or genotoxic agents, (i.e Benzo[a]Pyrene, Indeno[1,2,3-cd]Pyrene, Benzo[b]Fluoranthene, Benzo[k]Fluoranthene and Benzo[g,h,i]Perylene), had a large contribution (∼50-55%) of total PAHs concentration in PM10 in two sites and in each of the campaigns. Diagnostic ratio analysis and PCA suggested a substantial contributions from traffic emission with minimal influence from coal combustion and natural gas emissions. In particular diesel vehicular emissions were the major source of PAHs at the studied sites. The use of Toxicity Equivalence Quantity (TEQ) concentration provide a better estimation of carcinogenicity activities; health risk to adults and children associated with PAHs inhalation was assessed by taking into account the lifetime average daily dose and corresponding incremental lifetime cancer risk (ILCR). The ILCR was within the acceptable range (10-6-10-4), indicating a low health risk to residents in these areas.

  13. Occurrence and Source Appraisal of Polycyclic Aromatic Hydrocarbons (PAHs) in Surface Waters of the Almendares River, Cuba.

    PubMed

    Santana, Jorge Luis; Massone, Carlos German; Valds, Michel; Vazquez, Rene; Lima, Lzaro Antonio; Olivares-Rieumont, Susana

    2015-08-01

    In this work, 14 polycyclic aromatic hydrocarbons (PAHs) included in the United States Environmental Protection Agency pollutant priority list were analyzed in the surface water of the upper urbanized part of Almendares River, the most important water course in Havana, Cuba. Surface water from five sampling sites was collected at the end of dry season and analyzed by high-performance liquid chromatography-fluorescence detection method after solid phase extraction procedure. Total PAHs concentrations varied from 836 to 15 811ngL(-1) with a geometric mean value of 2512ngL(-1). PAH typology was dominated by low molecular-weight PAHs (2- to 3-ring components). Pollutant source appraisal was determined by diagnostic ratios method in five sampling sites. Factor analysis of normalized samples was used to concentration identified two factors as the main significant pollutant sources and to cluster similar sampling sites corresponding to petrogenic and combustion inputs, respectively. Ecological risks were considered. For animal aquatic life, acute toxicity values exceed the permissible values in the more-polluted sampling sites. PMID:25736902

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

    PubMed

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

    2015-03-01

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

  15. PAH emission from a gasoline-powdered engine

    SciTech Connect

    Mi, H.H.; Lee, W.J.; Wang, L.C.; Lin, T.A.; Chao, H.R.; Wu, T.L.

    1996-09-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2004-06-01

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

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

    PubMed

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

    2001-06-29

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

    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.

  19. Diagnostic evaluation of creatine kinase-2 mass and creatine kinase-3 and -2 isoform ratios in early diagnosis of acute myocardial infarction.

    PubMed

    Bhayana, V; Cohoe, S; Leung, F Y; Jablonsky, G; Henderson, A R

    1993-03-01

    The diagnostic efficacy of creatine kinase (CK) isoforms (CK-3 and CK-2) was compared with measurement of CK-2 mass concentrations for the early diagnosis of myocardial infarction (MI). Serial serum samples drawn from 76 patients with confirmed MI and 55 non-MI patients were used for determining CK-2 mass concentrations and the MM3/MM1 (CK-3 isoforms) and MB2/MB1 (CK-2 isoforms) ratios. We compared the diagnostic utility of each by receiver-operating-characteristic (ROC) curve and likelihood ratio analyses. Our results indicate that all three tests were ineffective within the first 4 h after the onset of chest pain. All three were most effective at 4-18 h after onset, but both CK-3 and CK-2 isoform ratios were less effective than CK-2 mass concentrations in the next 6-h period (18-24 h). In the critical time between 3 and 6 h, the diagnostic performance of all three was comparable. PMID:8448862

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

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

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

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

    PubMed

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

    2016-02-01

    Gas phase polycyclic aromatic hydrocarbons (PAHs) in Hexi Corridor, Northwest China were determined during heating and non-heating seasons, respectively, using passive air samplers. Polyurethane foam (PUF) disks were chosen as the sampling medium. Fifteen PAHs out of the 16 PAHs classified by the United States Environmental Protection Agency (U.S. EPA) were detected in this field sampling investigation. The atmospheric levels of sampled PAHs were higher at urban sites than that at rural sites among 14 sampling sites and increased during heating season. The highest concentration (11.34 ng m(-3)) was observed in Lanzhou during the heating season, the capital and largest industrial city of Gansu Province. PAH contamination in air was dominated by three aromatic ring congeners. Possible sources of PAHs were apportioned using PAH species ratios and the principle component analysis (PCA) combined with a multiple linear regression (MLR) method. Fossil fuel consumption was identified to be the predominant source of PAHs over Hexi Corridor, accounting for 43 % of the concentration of total (15) PAHs. Backward and forward trajectory and cluster analysis were also carried out to identify potential origins of PAHs monitored at several urban and rural sites. Lung cancer risk of local residents to gas phase PAHs via inhalation exposure throughout the province was found to be around a critical value of the lung cancer risk level at 10(-6) recommended by the U.S. EPA risk assessment guideline. PMID:26432264

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

    NASA Astrophysics Data System (ADS)

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

    2005-12-01

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

  3. Particulate matter, gaseous and particulate polycyclic aromatic hydrocarbons (PAHs) in an urban traffic tunnel of China: Emission from on-road vehicles and gas-particle partitioning.

    PubMed

    Liu, Ying; Gao, Yi; Yu, Na; Zhang, Chenkai; Wang, Siyao; Ma, Limin; Zhao, Jianfu; Lohmann, Rainer

    2015-09-01

    Traffic vehicles are a main source of polycyclic aromatic hydrocarbon (PAH) emission in urban area. It is vital to understand PAH gas-particle partitioning in real traffic environment and assess PAH vehicular emission factors in developing China. Concentrations of particulate matter, carbonaceous products, gaseous and particulate PAHs were measured during 2011-2012 in a road tunnel of Shanghai, China. Time variation of them reflected basic traffic operation of the tunnel. PAHs approached equilibrium between gas and particle phases and the partitioning was predicted better by a dual sorption model combining absorption into organic matter and adsorption onto black carbon. The influence of black carbon adsorption on the partitioning behavior of PAHs was important. The difference in isomer ratios of gaseous and particulate PAHs was attributed to PAH contributions from different traffic-related PAHs sources. Real-world vehicle emission factors of gaseous and particulate PAHs were quantified based on fuel burned model and vehicle kilometer traveled model. PMID:25911047

  4. Distribution of PAHs in the northwestern part of the Japan Sea

    NASA Astrophysics Data System (ADS)

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

    2013-02-01

    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.

  5. PAHs in the LMC and comparison to other galaxies

    NASA Astrophysics Data System (ADS)

    Hony, S.; SAGE-Spec Team

    2011-05-01

    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.

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

    PubMed

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

    2014-08-30

    The concentrations of 16 individual and total polycyclic aromatic hydrocarbons (?PAHs) in sediments, roots and leaves of three mangrove swamps in Shenzhen, China, namely Futian, Baguang and Waterlands, were determined. The mean concentration of ?PAHs in Futian (4480 ng g(-1)) was significantly higher than that in Baguang (1262 ng g(-1)) and Waterlands (2711 ng g(-1)). Among the 16 PAHs, the concentration of naphthalene was the highest. Based on the ratios of phenanthrene/anthracene and fluoranthene/pyrene, PAHs in Futian and Waterlands came from petrogenic and pyrolytic sources, while Baguang was mainly from pyrolytic. More PAHs were accumulated in leaves, as reflected by its higher mean concentration of ?PAHs (3697 ng g(-1)) and bioconcentration factor of PAHs (BCF) (>1.5) than that in roots. The BCF values in plants collected from Futian were significantly higher than that from Waterlands. These results indicated that more attention should be paid to the PAH contamination in Futian. PMID:24631400

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

    PubMed Central

    Kim, Daekyun; Young, Thomas M.

    2009-01-01

    Abstract To investigate the main inputs and sources of polycyclic aromatic hydrocarbons (PAHs) into surface water, stream and precipitation samples were collected along an urban tributary to the Sacramento River, California. Dissolved, particulate, and colloid-bound PAHs were monitored four times between October 2004 and March 2005. The total PAH concentrations ranged from 192 to 3784?ng/L in surface water and from 77 to 236?ng/L in precipitation. Naphthalene, phenanthrene, pyrene, and benzo[g,h,i]perylene were the most abundant compounds in both rain and surface water. Surface water had truly dissolved PAH concentrations between 18 and 48?ng/L and precipitation had similar values (1566?ng/L). PAHs larger than four rings were seldom found in the dissolved phase. Colloid-associated PAHs accounted for 425% of the total PAHs in rain, while they contributed only 0.16% to the total surface water PAHs. Indirect deposition (i.e., washoff of atmospheric particles previously deposited to land) of PAHs into surface water is likely a more significant input pathway for total PAHs than direct dry or wet deposition during the wet season in California's Mediterranean climate. During the sampling period, there was not an obvious seasonal variation in dissolved PAH concentrations of surface water despite an enormous wintertime increase in the total aqueous concentrations. Particulate matter carried by stormwater runoff was the major source of PAHs in surface water in the early rainy season; this material likely represents a combination of indirect atmospheric inputs and other non-atmospheric anthropogenic inputs (e.g., oil leaks and spills). Selected PAH ratios indicate that observed PAHs in rainwater came from pyrogenic sources and those in surface water had more complicated and variable origins. PMID:20485462

  8. Removal of polycyclic aromatic hydrocarbons (PAHs) from inorganic clay mineral: Bentonite.

    PubMed

    Karaca, Gizem; Baskaya, Hseyin S; Tasdemir, Ycel

    2016-01-01

    There has been limited study of the removal of polycyclic aromatic hydrocarbons (PAHs) from inorganic clay minerals. Determining the amount of PAH removal is important in predicting their environmental fate. This study was carried out to the degradation and evaporation of PAHs from bentonite, which is an inorganic clay mineral. UV apparatus was designed specifically for the experiments. The impacts of temperature, UV, titanium dioxide (TiO2), and diethylamine (DEA) on PAH removal were determined. After 24h, 75 and 44% of ?12 PAH in the bentonite were removed with and without UV rays, respectively. DEA was more effective as a photocatalyst than TiO2 during UV application. The ?12 PAH removal ratio reached 88% with the addition of DEA to the bentonite. It was concluded that PAHs were photodegraded at high ratios when the bentonite samples were exposed to UV radiation in the presence of a photocatalyst. At the end of all the PAH removal applications, higher evaporation ratios were obtained for 3-ring compounds than for heavier ones. More than 60% of the amount of ?12 PAH evaporated consisted of 3-ring compounds. PMID:26531715

  9. A Study of the PAH Bands in the LMC

    NASA Astrophysics Data System (ADS)

    Madden, Suzanne C.; Hony, S.; Galliano, F.; Galametz, M.; Kemper, C.; SAGE-SPEC Team

    2010-01-01

    The IR emission features between 3 and 20 microns are generally attributed to a family of large aromatic molecules in space. They are commonly referred to as "PAH features" even if the exact carriers are not yet identified. The PAH emission bands are proving to be more and more important astrophysical probes of star formation tracers and as a consequence can be used to distinguish between different types of galaxies. The different band ratios are know to vary from source to source and as a function of local galactic environment. 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 provides a unique possibility to study the environmental influence on the PAH emission features. In this work we study the Sage-SPEC extended maps which cover a wide range of targets from relatively quiescent regions to the most actively star forming regions in the LMC for which spectral maps have been obtained. In the poster we present our study aiming to disentangle the dominating parameters that determined the spectrum of PAH features, by correlating the properties of the PAHs spectra and the band ratios with a variety of other tracers from Spitzer, exploring the differing conditions in the diffuse ISM and the denser regions in the LMC.

  10. Lagdo Dam Flood Disaster of 2012: An Assessment of the Concentrations, Sources, and Risks of PAHs in Floodplain Soils of the Lower Reaches of River Niger, Nigeria.

    PubMed

    Tesi, Godswill O; Iwegbue, Chukwujindu M A; Emuh, Fidelis N; Nwajei, Godwin E

    2016-01-01

    The concentrations of the USEPA 16 priority polycyclic aromatic hydrocarbons (PAHs) in soils of the floodplain of the lower reaches of River Niger, Nigeria, were investigated following the Lagdo Dam flood disaster of 2012. The aim was to provide information on the extent of contamination, sources, and risks of PAHs in these soils. The concentrations of Σ16 PAHs in the floodplain soils ranged from 812 to 10,700 μg kg. The benzo(a)pyrene (BaP) toxic equivalence and incremental lifetime cancer risk (ILCR) factors were used to evaluate the risk of human exposure to PAHs in these soils. The concentrations of benzo(a)pyrene carcinogenic equivalence (BaP) and benzo(a)pyrene mutagenic equivalence (BaP) ranged from not detected to 4090 μg kg and not detected to 4150 μg kg, respectively. The total ILCR for children and adults was calculated as the summation of the individual risks through the three routes of exposure, (ingestion, dermal, and inhalation of vapor or dust). The values obtained indicate that there are 6450 and 4480 chances in one million equally exposed persons to develop the risk of cancer for children and adults, respectively, which were higher than the USEPA acceptable guideline value of one cancer case in one million (10) equally exposed persons. The PAHs source evaluation, using the diagnostic ratios and principal component analysis (PCA), indicated that the major sources of PAHs in these soils were fossil fuel combustion, gas flaring, wood combustion, traffic emissions, and input from petroleum. PMID:26828186

  11. Distribution and origins of polycyclic aromatic hydrocarbons (PAHs) in riverine, estuarine, and marine sediments in Thailand.

    PubMed

    Boonyatumanond, Ruchaya; Wattayakorn, Gullaya; Togo, Ayako; Takada, Hideshige

    2006-08-01

    To assess the status of polycyclic aromatic hydrocarbon (PAH) contamination in coastal and riverine environments in Thailand, we collected 42 surface sediment samples from canals, a river, an estuary, and coastal areas in Thailand in 2003 and analyzed them for PAHs with 3-7 benzene rings by gas chromatography-mass spectrometry (GC-MS). The total concentration of PAHs ranged from 6 to 8399 ng/g dry weight. The average total PAH concentrations were 2290+/-2556 ng/g dry weight (n=8) in canals, 263+/-174 (n=11) in the river, 179+/-222 (n=9) in the estuary, and 50+/-56 (n=14) in coastal areas. Comparison of the concentration range with a worldwide survey of sedimentary PAH concentrations ranked PAH contamination in Thai sediments as low to moderate. The ratio of the sum of methylphenanthrenes to phenanthrene (MP/P ratio) allows discrimination of PAH sources between petrogenic (>2) and pyrogenic (<0.5) origins. Sediments from urban canals in Bangkok showed the highest PAH concentrations and petrogenic signatures (MP/P=1.84+/-0.98 [n=6] in canal sediments) with abundant alkylated PAHs, indicating major sources of petrogenic PAHs in the city. To identify the sources of the petrogenic inputs in Thailand, we analyzed triterpanes, biomarkers of petroleum pollution, in the sediment samples and in potential source materials. Hopane profiles were remarkably uniform throughout the nation, suggesting a diffuse single source (e.g. automobiles). Molecular profiles of hopanes and PAHs in sediments from the urban canals were similar to those in street dust, indicating that street dust is one of the major sources of petrogenic PAHs in the urban area. On the other hand, low levels of PAHs (approximately 50 ng/g) with a pyrogenic signature (MP/P ratio approximately 0.5) were widely recorded in remote areas of the coast and the Chao Phraya River. These pyrogenic PAHs may be atmospherically transported throughout the nation. Middle and lower reaches of the Chao Phraya River, the river mouth, and the upper Gulf of Thailand showed intermediate concentrations and profiles of PAHs, indicating mixtures of petrogenic and pyrogenic origins. Perylene was abundant in sediments, representing up to approximately 60% of total identified PAHs. High inputs of soil due to frequent heavy rains could contribute to the high perylene abundance in the sediments. Sedimentary PAH concentrations decreased offshore with a half distance of approximately 10 km in the upper Gulf off the mouth of the Chao Phraya River. This is probably due to active deposition of laterally transported riverborne particles. PMID:16487985

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

    PubMed

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

    2014-02-01

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

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

    SciTech Connect

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

    1996-02-01

    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.

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

    PubMed

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

    2010-12-24

    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

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

    PubMed

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

    2012-03-01

    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

  16. Spatial and seasonal atmospheric PAH deposition patterns and sources in Rhode Island

    NASA Astrophysics Data System (ADS)

    Schifman, Laura A.; Boving, Thomas B.

    2015-11-01

    Polycyclic aromatic hydrocarbons (PAH) enter the environment through various combustion processes and can travel long distances via atmospheric transport. Here, atmospheric PAH deposition was measured in six locations throughout Rhode Island using passive atmospheric bulk-deposition samplers for three years. The measurements were evaluated using two source-specific PAH isomer signatures, a multivariate receptor model, and an innovative contamination index that is weighted based on PAH contamination, number of detected compounds, and toxicity. Urban areas had significantly higher deposition rates (up to 2261 μg m-2 yr-1 ∑PAH) compared to peri-urban, coastal, and rural areas (as low as 73.6 μg m-2 yr-1 ∑PAH). In fall and winter, PAH deposition was up to 10 times higher compared to summer/spring. On an annual basis a total of 3.64 t yr-1 ∑PAH (2256.9 μg yr-1 m-2 ∑PAH) are estimated to be deposited atmospherically onto Rhode Island. Both, the analysis using isomer ratios and the statistical analysis using positive matrix factorization agreed on source identification. Overall gasoline, petrodiesel, and oil combustion sources were identified in all samples year-round while wood combustion associated PAH deposition was only detected during the cold season.

  17. The impact of urbanization on tropical mangroves (Fortaleza, Brazil): evidence from PAH distribution in sediments.

    PubMed

    Cavalcante, Rivelino M; Sousa, Francisco W; Nascimento, Ronaldo F; Silveira, Edilberto R; Freire, George S S

    2009-01-01

    This investigation represents the first environmental diagnosis of the distribution and sources of polycyclic aromatic hydrocarbons (PAHs) in sediments from a tropical mangrove in Fortaleza, northeastern Brazil. Sediment cores from six sampling stations in the Coc and Cear Rivers were retrieved in June-July 2006 to determine 17 priority PAHs. The total PAH concentrations (Sigma(PAHs)) ranged from 3.04 to 2234.76 microg kg(-1)(Coc River) and from 3.34 to 1859.21 microg kg(-1) (Cear River). These levels are higher than those of other cities with more industrial development. PAH concentrations did not reach probable effect levels (PELs). However, from 4.5 to 87.5% of individual PAH concentrations can occasionally cause adverse biological effects for aquatic organisms. The PAH molecular ratios indicate that the PAHs in the sediment core were derived mainly from petroleum, wood, and charcoal combustion (pyrogenic source), and that atmospheric deposition and urban runoff may serve as important pathways for PAH input to the sediment. Clearly, the Sigma(PAHs) in sediments collected in the Coc and Cear Rivers indicate that ongoing pollution is more severe than past pollution. PMID:19889496

  18. Distribution of polycyclic aromatic hydrocarbons (PAHs) in Henan Reach of the Yellow River, Middle China.

    PubMed

    Sun, Jian-Hui; Wang, Guo-Liang; Chai, Yan; Zhang, Gan; Li, Jun; Feng, Jinglan

    2009-07-01

    The distribution and source of 16 polycyclic aromatic hydrocarbons (PAHs) in Henan Reach of the Yellow River, Middle China, has been investigated. summation sigmaPAHs levels ranged from 144.3 to 2361 ng L(-1) in water, from 506.6 to 10,510 ng g(-1) in suspended particulate matters (SPMs) and from 16.4 to 1358 ng g(-1) in sediment, respectively. The compositional profile of PAHs revealed that 2-3-ring PAHs were predominated in water and 2-4-ring PAHs were abundant in SPMs. Whereas the PAHs in sediment were composed mainly of 3-5-ring PAHs. The spatial distribution of PAHs indicated that concentrations of PAHs in water and SPMs in dry season were much higher than those in flooding season. It may be attributed to a high flow rate in flooding season. The ratios of phenanthrene/anthracene (Phe/Ant) and fluoranthene/pyrene (Flua/Pyr) reflected a pattern of pyrogenic input. The potential ecosystem risk assessment indicated that the ecosystem risk of PAHs was relatively low in Henan Reach of the Yellow River. PMID:18597847

  19. Analysis of serum PAH`s and PAH adducts by LC/MS

    SciTech Connect

    McClure, P.C.; Barr, J.R.; Maggio, V.L.

    1995-12-31

    Polycyclic aromatic hydrocarbons are an important class of chemical carcinogens. Benzo[a]pyrene is the most extensively studied and best understood carcinogenic PAH It is believed that Benzo[a]pyrene is metabolized in vitro to the diol epoxide, Benzo[a]pyrene-7,8-dihydrodiol-9, 10-epoxide which then can react with various nucleophilic centers on DNA. The major alkylation product appears to be the reaction of the Benzo[a]pyrene diol epoxide with the N{sup 2} position of guanine sites on DNA. Methods that can measure exposure and biological response to carcinogens such as PAH`s are needed. Human Blood can be separated into plasma, lymphocytes, and red blood cells. The plasma should contain native PAH`s which may yield some useful information about recent exposure. The red blood cells contain hemoglobin and adducts of PAH`s. Hemoglobin has an average lifetime of 120 days so quantification of hemoglobin adducts should give an average of a persons exposure over four months. Also, the electrophilic metabolites that react with hemoglobin to form adducts are the same metabolites that form DNA adducts which can lead to mutations and cancer. Lymphocytes contain DNA and therefore DNA adducts. DNA adducts can be repaired by a series of enzymes so quantification of these adducts will only yield information about recent or non-repairable adducts. DNA adduct formation is believed to be the first important step in chemical carcinogenesis so quantification of these adducts should yield some information on exposure and a great deal of important data on biological response and risk from specific PAH`s.

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

    NASA Astrophysics Data System (ADS)

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

    2011-07-01

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

  1. Pyroelectric array horizon sensor (PAHS)

    NASA Astrophysics Data System (ADS)

    Vasey, Martin; Clark, Chris

    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 at the sensor or spacecraft level. The first Quantic PAHS will be flown on the Office of Naval Research's SPINSAT.

  2. PAH Emission From ULIRGs: Evidence For Unusual Grain Properties?

    NASA Astrophysics Data System (ADS)

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

    2007-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2011-03-01

    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.

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

    PubMed Central

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

    2015-01-01

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

  5. Distribution and accumulation of polycyclic aromatic hydrocarbons (PAHs) in the food web of Nansi Lake, China.

    PubMed

    Zhang, Guizhai; Pan, Zhaoke; Wang, Xiaoming; Mo, Xiaojie; Li, Xiaoming

    2015-04-01

    The concentrations of polycyclic aromatic hydrocarbons (PAHs) were analyzed in water, sediment, and biota (aquatic plant, shrimp, and fish) of Nansi Lake by gas chromatography-mass spectrometry (GC-MS). The concentrations of total PAHs were 27.54-55.04 ng L(-1) in water, 80.31-639.23 ng g(-1) dry weight (dw) in sediments, 20.92-192.78 ng g(-1) dw in aquatic plants, and 67.3-533.9 ng g(-1) dw in fish and shrimp muscles. The ratios of phenanthrene to anthracene (Ph/An), fluoranthene to pyrene (Flu/Pyr), and low molecular weight to high molecular weight (LMW/HMW) in sediment indicated that the sources of the PAHs were a mixture of pyrolytic and petrogenic contamination at most sampling sites in Nansi Lake. The composition profile of PAHs in plants was similar to that in water and animals with 2-3 ring PAHs being dominant. The 4-6 ring PAHs were the dominant PAH compounds in sediment. There is a positive correlation between sediment and aquatic plants, but their PAH composition profiles were different, implying that aquatic plant absorption of PAHs from sediment is selective and the accumulation of PAHs in aquatic plants is different. The concentration of PAHs in fish showed a positive correlation with plants, reflecting that the PAHs in fish are mainly absorbed from aquatic plants rather than directly from the water. Bioaccumulation of LMW PAHs in aquatic biota was higher than HMW PAHs. The biota-sediment accumulation factor (BSAF) values of total PAHs in the plants Potamogeton lucens Linn and Ceratophyllum demersum Linn were higher than that in most animals. The BSAF values of total PAHs in animals were in the following order: Cyprinus carpio>Macrobrachium nipponense>Carassius auratus>Channa argus. There was no significant relationship between PAH bioaccumulation and trophic levels in Nansi Lake. Risk assessment of PAHs in water, sediment, and animals indicated that the water environment of Nansi Lake is safe at present. It is worthwhile to note that benzo [a] anthracene (BaA), benzo [a] pyrene (BaP), indeno [1,2,3-cd] pyrene (InP), dibenz [a, h] anthracene (DBA), and benzo [ghi] perylene (BghiP) were detected in sediment, plants, and animals at all sampling sites, and they have potential carcinogenicity to the organisms of Nansi Lake. PMID:25762425

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

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

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

  7. Occurrence and profiles of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in soils from a typical e-waste recycling area in Southeast China.

    PubMed

    Liao, Chunyang; Lv, Jungang; Fu, Jianjie; Zhao, Zongshan; Liu, Fang; Xue, Qinzhao; Jiang, Guibin

    2012-01-01

    Surface soils collected from Taizhou, a typical e-waste recycling area in Southeast China, were analyzed for the residues of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs) by using microwave-assisted extraction and gas chromatography -mass spectrometry (GC-MS). The total concentrations of 16 PAHs in US EPA's priority list (?PAHs), six indicator PCBs (?PCBs), 15 OCPs widely used in China (?OCPs) in soils ranged from 125 to 4737ng/g (average: 854 ng/g), from not detected to 55.4ng/g (3.16ng/g), and from 47.9 to 820ng/g (276ng/g), respectively. Individual PAHs were ubiquitously found in soil samples with detected ratio of 96% and their residual levels were comparable with those of serious polluted sites. Principal component analysis in combination with diagnostic ratios suggested that the combustion of coal, wood, and plastic wastes that are closely associated with illegal and unsafe recycling operations of e-wastes was the main source of PAHs in this area. Compared with other polluted sites, the PCBs residues in soils were generally low except for those in the major recycling site. The residual levels of OCPs in this region were also relatively higher and hexachlorocyclohexane (HCH), dichlorodiphenyltrichloroethane (DDT) and its metabolite forms including dichlorodiphenyldichloroethane (DDD) and dichlorodiphenyldichloroethylene (DDE), hexachlorobenzene (HCB), and dicofol were dominant species. The composition analysis indicated that the HCHs residues in soils might originate from the application of lindane (pure?-HCH) and parts of DDTs possibly from the wide use of dicofol with high impurity of DDT compounds in this region. PMID:22098496

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

    PubMed

    Zhao, Xuesong; Ding, Jing; You, Hong

    2014-02-01

    The spatial and temporal distributions of polycyclic aromatic hydrocarbons (PAHs) in the Songhua River, Harbin, China, were investigated. Seventy-seven samples, 42 water and 35 sediment samples, were collected in April and October of 2007 and January of 2008. The concentrations of total PAHs in water ranged from 163.54 to 2,746.25ng/L with the average value of 934.62ng/L, which were predominated by 2- and 3-ring PAHs. The concentrations of total 16 PAHs in sediment ranged from 68.25 to 654.15ng/g dw with the average value of 234.15ng/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 29.7ng/g dw and from 0.36 to 1.92ng/g dw for total toxic tetrachlorodibenzo-p-dioxin equivalent. The level of PAHs indicated a low toxicological risk to this area. PMID:23609889

  9. Neck Muscles and Content of Carotid Artery as Reference Tissue for Strain Ratio - a Novel Approach to Improve the Diagnostic Performance of Thyroid Elastography?

    PubMed

    Kratky, J; Vitkova, H; Bartakova, J; Lukas, J; Jiskra, J

    2016-03-01

    Measurement of thyroid nodule stiffness by strain elastography already showed promising results. The aim of our study was to evaluate the diagnostic performance of elastography in predicting thyroid cancer by determination of strain ratio comparing nodule stiffness with thyroid tissue and surrounding neck tissues as well (carotid artery, neck muscles). Totally, 310 thyroid nodules in 275 patients were examined by conventional ultrasound and elastography prior to aspiration biopsy. 22(7.1%) thyroid carcinomas were histologically confirmed and included in the study. 39 benign nodules (27 confirmed by histology and 12 with benign cytology and at least 2 years stable ultrasound finding) formed control group. Elastography was evaluated qualitatively using 6-grade score and strain ratio to surrounding thyroid tissue, carotid artery and neck muscles was determined. High-risk elastographic score (4,5) was more frequent in carcinomas (67%) compared with benign nodules (11%, p<0.001). Significant differences in distribution of strain were found in all studied parameters except comparison with thyroid tissue in transversal dimension. Strain ratio comparing the stiffness with neck muscles had a higher negative predictive value than elastographic score and conventional ultrasound (92 vs. 83 and 82% respectively). Moreover, the combination of ultrasound and strain ratio to neck muscles increased sensitivity and negative predictive value to 100%. Our results suggest, that strain ratio to neck muscles in combination with ultrasound seems to have good sensitivity and negative predictive value for predicting thyroid cancer and may be beneficial in cases when comparison to surrounding thyroid tissue is problematic (Hashimoto thyroiditis, multinodular goiter, large nodule). PMID:27008636

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

    PubMed

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

    2016-01-15

    The distribution, sources and risk assessment of 16 polycyclic aromatic hydrocarbons (PAHs) of surface sediments in the Luan River Estuary, China, have been investigated in the research. The results indicated that the total concentrations of 16 PAHs in surface sediments of the Luan River Estuary ranged from 5.1 to 545.1ngg(-1)dw with a mean value of 120.8ngg(-1)dw, which is relatively low in comparison with other estuaries around the world. The PAHs in the study area were mainly originated from pyrogenic sources. Besides, PAHs may be contaminated by petrogenic PAHs as indicated by the selected ratios of PAHs, the 2-tailed Pearson correlation analysis and principal components analysis at different sites. The result of the ecological risk assessment shows little negative effect for most individual PAHs in surface sediments of the Luan River Estuary, China. PMID:26616744

  11. Pollution assessment, distribution and sources of PAHs in agricultural soils of Pearl River Delta--the biggest manufacturing Base in China.

    PubMed

    Li, Yongtao; Li, Fangbai; Zhang, Tianbin; Yang, Guoyi; Chen, Junjian; Wan, Hongfu

    2007-11-01

    A large scale of soil survey was performed to determine the contents, distributions and sources of 16 polycyclic aromatic hydrocarbons (PAHs) in 231 agricultural soils under 3 land-use types from 5 regions of the subtropical Pearl River Delta (PRD). The average sum of 16 PAHs in all soil samples is 316.5 micro g.kg(-1), with range from ND to 4079 micro g.kg(-1). Three- and 4-ring PAHs are the most abundant PAHs that contribute to 73.0% of total contents. The most abundant components are phenanthrene, benzo(b)fluoranthene and fluoranthene. ANOVA and principal component analyses (PCA) indicate that soil samples from Dongguan and Zhongshan contain greater PAHs than other regions. More abundant carcinogenic and higher molecular weight PAHs accumulated in soils from Dongguan and Zhongshan, while higher low molecular weight PAHs were in soils from Guanghzou, Huizhou and Shunde. Soil PAHs from 3 land uses are not statistically different. Additionally, 5 PAH compound ratios suggest that soil PAHs in PRD derived from mixture of pyrogenic and petrogenic sources, but the majorities are pyrogenic sources. PAHs were further identified as mixture of petroleum combustion and grass, wood, and coal combustion. Some soil PAHs were revealed vehicle emission, coal soot and petroleum sources. The 5 regions showed different PAHs sources according to some compound ratios, but no marked distinction between regions from 2 banks of the Pearl River because of major wind direction, distribution of riverway and industry. PMID:17990160

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

    SciTech Connect

    Eisensmith, R.C.; Woo, S.L.C. )

    1992-12-01

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

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

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

    2015-01-01

    Farmland soil and leafy vegetables accumulate more polycyclic aromatic hydrocarbons (PAHs) in suburban sites. In this study, 13 sampling areas were selected from vegetable fields in the outskirts of Xi'an, the largest city in northwestern China. The similarity of PAH composition in soil and vegetation was investigated through principal components analysis and redundancy analysis (RDA), rather than discrimination of PAH congeners from various sources. The toxic equivalent quantity of PAHs in soil ranged from 7 to 202 ?g/kg d.w., with an average of 41 ?g/kg d.w., which exceeded the agricultural/horticultural soil acceptance criteria for New Zealand. However, the cancer risk level posed by combined direct ingestion, dermal contact, inhalation of soil particles, and inhalation of surface soil vapor met the rigorous international criteria (1 10(-6)). The concentration of total PAHs was (1052 73) ?g/kg d.w. in vegetation (mean standard error). The cancer risks posed by ingestion of vegetation ranged from 210-5 to 2 10(-4) with an average of 1.66 10(-4), which was higher than international excess lifetime risk limits for carcinogens (1 10(-4)). The geochemical indices indicated that the PAHs in soil and vegetables were mainly from vehicle and crude oil combustion. Both the total PAHs in vegetation and bioconcentration factor for total PAHs (the ratio of total PAHs in vegetation to total PAHs in soil) increased with increasing pH as well as decreasing sand in soil. The total variation in distribution of PAHs in vegetation explained by those in soil reached 98% in RDA, which was statistically significant based on Monte Carlo permutation. Common pollution source and notable effects of soil contamination on vegetation would result in highly similar distribution of PAHs in soil and vegetation. PMID:25679782

  15. Chemical characterization and spatial distribution of PAHs and heavy hydrocarbons in rural sites of Campania Region, South Italy.

    PubMed

    Monaco, D; Riccio, A; Chianese, E; Adamo, P; Di Rosa, S; Fagnano, M

    2015-10-01

    In this paper, the behaviour and distribution patterns of heavy hydrocarbons and several polycyclic aromatic hydrocarbon (PAH) priority pollutants, as listed by the US Environmental Protection Agency, were evaluated in 891 soil samples. The samples were collected in three expected polluted rural sites in Campania (southern Italy) as part of the LIFE11 ECOREMED project, funded by the European Commission, to test innovative agriculture-based soil restoration techniques. These sites have been selected because they have been used for the temporary storage of urban and building waste (Teverola), subject to illicit dumping of unknown material (Trentola-Ducenta), or suspected to be polluted by metals due to agricultural practices (Giugliano). Chemical analysis of soil samples allowed the baseline pollution levels to be determined prior to any intervention. It was found that these areas can be considered contaminated for residential use, in accordance with Italian environmental law (Law Decree 152/2006). Statistical analysis applied to the data proved that average mean concentrations of heavy hydrocarbons could be as high as 140 mg/kg of dry soil with peaks of 700 mg/kg of dry soil, for the Trentola-Ducenta site; the median concentration of analytical results for hydrocarbon (HC) concentration for the Trentola-Ducenta and Giugliano sites was 63 and 73.4 mg/kg dry soil, respectively; for Teverola, the median level was 35 mg/kg dry soil. Some PAHs (usually benzo(a)pyrene) also exceeded the maximum allowed level in all sites. From the principal component analysis applied to PAH concentrations, it emerged that pollutants can be supposed to derive from a single source for the three sites. Diagnostic ratios calculated to determine possible PAH sources suggest petroleum combustion or disposal practice. Our sampling protocol also showed large dishomogeneity in soil pollutant spatial distribution, even at a scale as small as 3.3 m, indicating that variability could emerge at very short spatial scales. PMID:26002373

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

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

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

  17. 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

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

    2012-01-15

    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.

  18. Recent Progress in DIB Research: Survey of PAHS and DIBS

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

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

  19. Source, profile, and carcinogenic risk assessment for cohorts occupationally exposed to dust-bound PAHs in Lahore and Rawalpindi cities (Punjab province, Pakistan).

    PubMed

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

    2015-07-01

    In this study, the occurrence and concentrations of PAHs in dust samples, which were collected from the traffic police cabins/working spots, located on the main busy roads of Lahore (TP-L) and Rawalpindi (TP-R) cities (Punjab province, Pakistan) and from the public transport vehicles in the same cities (named as AM-L and AM-R, respectively) were determined. The mean and median concentrations of ?PAHs were observed in the following descending order: AM-L (1340 and 774 ng g(-1) d.w., respectively), TP-L (866 and 854 ng g(-1) d.w.), TP-R (504 and 379 ng g(-1) d.w.), and AM-R (393 and 290 ng g(-1) d.w. Source apportionment of the soil/dust-bound PAHs was also performed. In all the sampling areas, the diagnostic ratios, principal component analysis (PCA) followed by multiple linear regression (MLR) analysis indicated signatures of mixed sources of PAHs (including vehicular exhaust emission, gasoline/diesel, and coal/wood combustion). Estimated results of incremental lifetime cancer risk (ILCR) indicated that the traffic policemen and drivers, especially those in the urban area of Lahore, were at high risk of cancer via routes of dust ingestion and dermal contact. The results of this research could be very useful for the local Government in order to control the exposure and promote actions to alleviate PAH contamination and to manage health both at work places in the big cities of Pakistan. PMID:25739839

  20. PM?.?-bound oxygenated PAHs, nitro-PAHs and parent-PAHs from the atmosphere of a Chinese megacity: seasonal variation, sources and cancer risk assessment.

    PubMed

    Bandowe, Benjamin A Musa; Meusel, Hannah; Huang, Ru-Jin; Ho, Kinfai; Cao, Junji; Hoffmann, Thorsten; Wilcke, Wolfgang

    2014-03-01

    Polycyclic aromatic compounds (PACs) in air particulate matter contribute considerably to the health risk of air pollution. The objectives of this study were to assess the occurrence and variation in concentrations and sources of PM2.5-bound PACs [Oxygenated PAHs (OPAHs), nitro-PAHs and parent-PAHs] sampled from the atmosphere of a typical Chinese megacity (Xi'an), to study the influence of meteorological conditions on PACs and to estimate the lifetime excess cancer risk to the residents of Xi'an (from inhalation of PM2.5-bound PACs). To achieve these objectives, we sampled 24-h PM2.5 aerosols (once in every 6 days, from 5 July 2008 to 8 August 2009) from the atmosphere of Xi'an and measured the concentrations of PACs in them. The PM2.5-bound concentrations of ?carbonyl-OPAHs, ?hydroxyl+carboxyl-OPAHs, ?nitro-PAHs and ?alkyl+parent-PAHs ranged between 5-22, 0.2-13, 0.3-7, and 7-387 ng m(-3), respectively, being markedly higher than in most western cities. This represented a range of 0.01-0.4% and 0.002-0.06% of the mass of organic C in PM2.5 and the total mass of PM2.5, respectively. The sums of the concentrations of each compound group had winter-to-summer ratios ranging from 3 to 8 and most individual OPAHs and nitro-PAHs had higher concentrations in winter than in summer, suggesting a dominant influence of emissions from household heating and winter meteorological conditions. Ambient temperature, air pressure, and wind speed explained a large part of the temporal variation in PACs concentrations. The lifetime excess cancer risk from inhalation (attributable to selected PAHs and nitro-PAHs) was six fold higher in winter (averaging 1450 persons per million residents of Xi'an) than in summer. Our results call for the development of emission control measures. PMID:24361780

  1. Biological PAH degradation in dredged sludges

    SciTech Connect

    Huis in`t Veld, M.G.A.; Werners, J.; Doddema, H.J.; Veen, J.J. van

    1995-12-31

    Sediment-associated PAHs are biodegraded by fungi under low pH conditions. The 16 polycyclic aromatic hydrocarbons (PAHs) targeted by the US Environmental Protection Agency (US EPA) are converted by more than 95% within a period of 20 weeks. The process appears to be a metabolic conversion, because PAH removal occurred in absence of additional growth substrates.

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

    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 relatively smaller than average concentrations measured previously at urban sites in the UK. The concentrations of PAH of the air masses originating from southern England and mainland UK are significantly larger than those from Eastern Europe 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 concentrations of 1,2-naphthoquinone decline from winter to summer, 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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

    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.

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

    PubMed

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

    2013-08-01

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

  5. Accumulation of policyclic aromatic hydrocarbons (PAHs) in surface litter and soils in four forests in the United States

    NASA Astrophysics Data System (ADS)

    Obrist, D.; Perlinger, J. A.; Zielinska, B.

    2014-12-01

    Polycyclic aromatic hydrocarbons (PAHs) are toxic environmental pollutants originating from the incomplete combustion of organic material, both from natural or anthropogenic sources. Once emitted, they can be transported across thousands of kilometers impacting remote environments. Here, we characterize the distribution of 23 PAHs and 9 oxygenated PAHs (Σ32PAH) in litter and soils in four remote forests in the United States. Concentrations of Σ32PAH in fresh surface litter (Oi layers) showed very low levels in three of the four forests (mixed coniferous forest in Maine, deciduous blue oak forest in California, and a coniferous forest in Washington State), with PAHs levels much lower than those reported in previous studies from Europe. The analysis showed that PAHs represented a mix of regional background sources. Highest PAH levels were observed in a coniferous forest floor in Florida, attributable to frequent prescribed burning of understory vegetation at this site, and supported by high contributions of retene (>7%; compared to <1% at other sites). Σ32PAH increased in deeper, more decomposed organic litter layers, increasing from 57±19 ng g-1 (in Oi layer) to 511± 285 ng g-1 in decomposed, humidified litter layers (Oe and Oa horizons). In mineral soils, Σ32PAH were over an order of magnitude lower (average 37±8 ng g-1), which was attributed to higher bulk densities of mineral soils. However, standardized per unit of organic carbon (OC), Σ32PAH:OC ratios in mineral soils also were below levels observed in overlying litter, indicating a strong sorption capacity of organic horizons for atmospheric deposition. Within mineral soils, Σ32PAH:OC ratios increased with depth (Ah horizons: 750±198 ng g-1; B horizons: 1,202±97 ng g-1), indicating that vertical transfer in mineral soils leads to significant accumulation of PAH in subsoils. ΣPAH:OC increases observed in deeper soil layers may be attributed to slower mineralization rates of PAHs compared to OC, plus vertical transport as indicated by preferential enrichment of PAHs with low Kow (i.e., more water-soluble PAHs). Finally, percentage of potentially biologically produced PAH (Σ Naph+Phen+Pery) were low and consistent across the litter/soil horizons, suggesting that biological production is minor or absent at our sites.

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

    PubMed

    Hong, Lei; Luthy, Richard G

    2008-05-01

    Polyoxymethylene (POM) is a polymeric material used increasingly in passive sampling of hydrophobic organic contaminants such as PAHs and PCBs in soils and sediments. In this study, we examined the sorption behavior of 12 PAH compounds to POM and observed linear isotherms spanning two orders of magnitude of aqueous concentrations. Uptake kinetic studies performed in batch systems for up to 54 d with two different volume ratios of POM-to-aqueous phase were evaluated with coupled diffusion and mass transfer models to simulate the movement of PAHs during the uptake process and to assess the physicochemical properties and experimental conditions that control uptake rates. Diffusion coefficients of PAHs in POM were estimated to be well correlated with diffusants' molecular weights as D(POM) proportional, variant(MW)(-3), descending from 2.3 x 10(-10) cm(2) s(-1) for naphthalene to 7.0 x 10(-11) cm(2) s(-1) for pyrene. The uptake rates for PAHs with log K(ow)<5.8 were controlled by the POM phase and the hydrophobicity of PAH compounds. For more hydrophobic PAH compounds, the aqueous boundary layer played an increasingly important role in determining the overall mass transfer rate. The POM partitioning technique was demonstrated to agree well with two other procedures for measuring PAH soil-water distribution coefficients in oil-soot (lampblack) containing soil samples. PMID:18334261

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

    PubMed

    Lang, Yin-Hai; Yang, Wei

    2014-01-01

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

  8. Atmospheric size distribution of PAHs: evidence of a high-volume sampling artifact.

    PubMed

    Sanderson, Eric G; Farant, J P

    2005-10-01

    The purpose of this study was to characterize atmospheric levels of four- to six-ring polycyclic aromatic hydrocarbons (PAHs) in the vicinity of a horizontal stud Sderberg aluminum smelter in terms of the size distribution of particulate matter (September to December 2002). It was found that the vast majority of the PAHs was associated with particle diameters less than 1 and 3 microm. A profile comparison of the PAH mixture--using benzo[a]pyrene (B[a]P) relative abundance ratios (PAH/B[a]P)--for the cascade impactor filters indicated the formation of a sampling artifact. Overall, the PAH stability scale generated in this study agrees with those produced experimentally for ozone and nitrogen dioxides or developed using other in situ measurement techniques. Correlations of the four- to six-ring PAHs with other atmospheric variables suggested that smelter plume conditions and particle characteristics may play a potentially important role in the overall PAH reactivity. To our knowledge, this is the first study to report a sampling artifact for the four- to six-ring PAHs during in situ high volume sampling under real world conditions. PMID:16245837

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

    PubMed

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

    2015-09-01

    We characterized distributions of 23 polycyclic aromatic hydrocarbons (Σ23PAH) and nine oxygenated PAHs (Σ9OPAH) in four remote forests. We observed highest Σ23PAH and Σ9OPAH concentrations in a coniferous forest in Florida, particularly in organic layers which we attributed to frequent prescribed burning. Across sites, Σ23PAH and Σ9OPAH concentrations strongly increased from surface to humidified organic layers (+1626%) where concentrations reached up to 584 ng g(-1). Concentrations in mineral soils were lower (average 37 ± 8 ng g(-1)); but when standardized per unit organic carbon (OC), PAH/OC and OPAH/OC ratios were at or above levels observed in organic layers. Accumulation in litter and soils (i.e., enrichment factors with depth) negatively correlated with octanol-water partition coefficients (Kow) and therefore was linked to water solubility of compounds. Concentrations of Σ9OPAHs ranged from 6 ± 6 ng g(-1) to 39 ± 25 ng g(-1) in organic layers, and from 3 ± 1 ng g(-1) to 11 ± 3 ng g(-1) in mineral soils, and were significantly and positively correlated to Σ23PAHs concentrations (r(2) of 0.90) across sites and horizons. While OPAH concentrations generally decreased from organic layers to mineral soil horizons, OPAH/OC ratios increased more strongly with depth compared to PAHs, in particular for anthrone, anthraquinone, fluorenone, and acenaphthenequinone. The strong vertical accumulation of OPAH relative to OC was exponentially and negatively correlated to C/N ratios (r(2)=0.67), a measure that often is used for tissue age. In fact, C/N ratios alone explained two-thirds of the variability in OPAH/OC ratios suggesting particularly high retention, sorption, and persistency of OPAHs in old, decomposed carbon fractions. PMID:25929871

  10. Oxidative biodegradation pathways of PAHs

    SciTech Connect

    Cerniglia, C.E.

    1993-12-31

    Polycyclic aromatic hydrocarbons (PAHs) constitute a class of hazardous organic chemical consisting of three of more fused benzene rings in linear, angular and cluster arrangements. PAHs mostly occur as a result of fossil fuel combustion, as by-product of industrial processing and during the cooking of foods. A catabolically diverse microbial community, consisting of bacteria, fungi and algae, metabolizes aromatic compounds. Molecular oxygen is essential for the initial hydroxylation of polycyclic aromatic hydrocarbons by microorganisms. In contrast to bacteria, filamentous fungi use hydroxylation as a prelude to detoxification rather than to catabolism and assimilation. The biochemical principles underlying the degradation of polycyclic aromatic hydrocarbons will be discussed. The oxidative pathways of polycyclic aromatic hydrocarbon catabolism will be discussed. Studies will be presented on the relationship between the chemical structure of the polycyclic aromatic hydrocarbon and the rate of polycyclic aromatic hydrocarbon biodegradation in aquatic and terrestrial ecosystems.

  11. The relationship between the properties of PAHs and AGN activities in type-I AGNs

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

    In order to explore the relationship between properties of Polycyclic Aromatic Hydrocarbons (PAHs) and AGN activities in Type-I AGNs, we compiled a sample of 47 Type-I AGNs with measured PAH 11.3 ?m and 7.7 ?m emission lines. The PAH emission and optical properties of these AGNs are taken from the literature. It is found that the equivalent width (EW) of 11.3 ?m emission from PAHs shows a weak correlation with the ratio of the EWs of the FeII complex between ?4434 and ?4684 to H? (RFe). The PAH 11.3/7.7 ratio is correlated with various elements defined by the first eigenvector space, which are RFe, [OIII]?5007 luminosity and H? asymmetry. These correlations infer that AGNs with high RFe, weak [OIII] emission and a strong H? blue-wing are likely to have low PAH ionization, and hence a larger amount of neutral PAHs. Supported by the National Natural Science Foundation of China.

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

    PubMed

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

    2015-01-01

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

  13. PAH phytoremediation: rhizodegradation or rhizoattenuation?

    PubMed

    Ouvrard, S; Leglize, P; Morel, J L

    2014-01-01

    Dealing with soil contaminated with persistent organic pollutants (POP) is an increasing concern amplified by both regulatory constraints and the dramatic impact of human activities on the soil resource. The most used management options are treatments which totally eradicate the toxic compounds targeted. When possible, environmental-friendly processes should be used, and recent years have seen the emergence of green technologies using biological energies involving microorganisms (bioremediation) and plants (phytoremediation). Research has focused on phytoremediation and many have presented this technology as the process ideally combining efficiency, low cost and environmental acceptance. However, the applicability of phytoremediation on soils contaminated by bio-recalcitrant organic compounds, such as polycyclic aromatic hydrocarbons (PAH), has not yet proved as successful as expected. We propose here a review and discussion of the overall question of PAH status in soil and their potential for treatment. The limits and applicability of bioremediation technologies are discussed, and the specific beneficial effect of plants is objectively evaluated with a special interest to processes which lead to rhizoattenuation. Given the PAH high affinity to soil organic matter, availability is the main limitation to phytoremediation. In this context, bioavailability quantification remains an issue as well as the characterization of the recalcitrant fraction. PMID:24912214

  14. Carcinogenic PAH in waterpipe charcoal products

    PubMed Central

    Sepetdjian, Elizabeth; Saliba, Najat; Shihadeh, Alan

    2010-01-01

    Because narghile waterpipe (shisha, hooka) smoking normally involves the use of burning charcoal, smoke inhaled by the user contains constituents originating from the charcoal in addition to those from the tobacco. We have previously found that charcoal accounts for most of the polyaromatic hydrocarbons (PAH) and carbon monoxide in the smoke of the waterpipe, both of which are present in alarming quantities. Because charcoal manufacturing conditions favor formation of PAH, it is reasonable to assume that charcoal sold off the shelf may be contaminated by PAH residues. These residues may constitute a significant fraction of the PAH inhaled by the waterpipe user and those in her/his vicinity. We measured PAH residues on three kinds of raw waterpipe charcoal sampled from Beirut stores and cafés. We found that PAH residues in raw charcoal can account for more than half of the total PAH emitted in the mainstream and sidestream smoke, and about one sixth of the carcinogenic 5- and 6-ring PAH compounds. Total PAH content of the three charcoal types varied systematically by a factor of six from the charcoal with the least to the greatest PAH residue. These findings indicate the possibility of regulating charcoal carcinogen content. PMID:20807559

  15. The hydrogen coverage of interstellar PAHs

    NASA Technical Reports Server (NTRS)

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

    1986-01-01

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

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

    PubMed

    Suman, Swapnil; Sinha, Alok; Tarafdar, Abhrajyoti

    2016-03-01

    Present study was carried out to assess and understand potential health risk and to examine the impact of vehicular traffic on the contamination status of urban traffic soils in Dhanbad City with respect to polycyclic aromatic hydrocarbons (PAHs). Eight urban traffic sites and two control/rural site surface soils were analyzed and the contents of 13 priority PAHs was determined. Total PAH concentration at traffic sites ranged from 1.019μgg(-1) to 10.856μgg(-1) with an average value of 3.488μgg(-1). At control/rural site, average concentration of total PAHs was found to be 0.640μgg(-1). PAH pattern was dominated by four- and five-ring PAHs (contributing >50% to the total PAHs) at all the eight traffic sites. On the other hand, rural soil showed a predominance of low molecular weight three-ring PAHs (contributing >30% to the total PAHs). Indeno[123-cd]pyrene/benz[ghi]perylene (IP/BgP) ratio indicated that PAH load at the traffic sites is predominated by the gasoline-driven vehicles. The ratio of Ant/(Ant+Phe) varied from 0.03 to 0.44, averaging 0.10; Fla/(Fla+Pyr) from 0.39 to 0.954, averaging 0.52; BaA/(BaA+Chry) from 0.156 to 0.60, averaging 0.44; and IP/(IP+BgP) from 0.176 to 0.811, averaging 0.286. The results indicated that vehicular emission was the major source for PAHs contamination with moderate effect of coal combustion and biomass combustion. Carcinogenic potency of PAH load in traffic soil was nearly 6.15 times higher as compared to the control/rural soil. PMID:26747999

  17. Reflectance spectroscopy (350-2500 nm) of solid-state polycyclic aromatic hydrocarbons (PAHs)

    NASA Astrophysics Data System (ADS)

    Izawa, M. R. M.; Applin, D. M.; Norman, L.; Cloutis, E. A.

    2014-07-01

    Polycyclic aromatic hydrocarbons (PAHs) are organic compounds based on fused aromatic rings, and are formed in a variety of astrophysical, solar nebula and planetary processes. Polycyclic aromatic hydrocarbons are known or suspected to occur in a wide variety of planetary settings including icy satellites, Titan’s hazes, carbonaceous meteorites, comet nuclei, ring particles; and terrestrial organic-rich lithologies such as coals, asphaltites, and bituminous sands. Relatively few measurements of the visible and near-infrared spectra of PAHs exist, yet this wavelength region (350-2500 nm) is widely used for remote sensing. This study presents detailed analyses of the 350-2500 nm reflectance spectra of 47 fine-grained powders of different high-purity solid-state PAHs. Spectral properties of PAHs change with variations in the number and connectivity of linked aromatic rings and the presence and type of side-groups and heterocycles. PAH spectra are characterized by three strong features near ∼880 nm, ∼1145 nm, and ∼1687 nm due to overtones of νCH fundamental stretching vibrations. Some PAHs are amenable to remote detection due to the presence of diagnostic spectral features, including: Nsbnd H stretching overtones at 1490-1515 nm in NH- and NH2-bearing PAHs, aliphatic or saturated bond Csbnd H overtone vibrations at ∼1180-1280 nm and ∼1700-1860 nm; a broad asymmetric feature between ∼1450 nm and ∼1900 nm due to Osbnd H stretching overtones in aromatic alcohols, Csbnd H and Cdbnd O combinations near ∼2000-2010 nm and ∼2060-2270 nm in acetyl and carboxyl-bearing PAHs. Other substituents such as sulphonyl, thioether ether and carboxyl heterocycles, or cyano, nitrate, and aromatic side groups, do not produce well-resolved diagnostic spectral features but do cause shifts in the positions of the aromatic Csbnd H vibrational overtone features. Fluorescence is commonly suppressed by the presence of heterocycles, side-groups and in many non-alternant PAHs. The spectral characteristics of PAHs offer the potential, under suitable circumstances, for remote characterization of the classes of PAH present and in some cases, identification of particular heterocyclic or side-group substituents.

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

    NASA Astrophysics Data System (ADS)

    Luo, X.; Zheng, Y.

    2012-12-01

    Polycyclic Aromatic Hydrocarbons (PAHs) transported by surface runoff result in nonpoint source pollution and jeopardize aquatic ecosystems. The transport mechanism of PAHs during rainfall-runoff events has been rarely studied regarding pervious areas. An experimental system was set up 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.To further explore the effect of different soil organic matters on the enrichment behavior, Organic petrology analysis can be applied. Schematic diagram of the experimental setup

  19. Concentrations and sources of PAHs in surface sediments of the Fenhe reservoir and watershed, China.

    PubMed

    Li, Wei-Hong; Tian, Ying-Ze; Shi, Guo-Liang; Guo, Chang-Sheng; Li, Xiang; Feng, Yin-Chang

    2012-01-01

    Sixteen PAHs in surface sediments at 28 sites throughout Fenhe reservoir and watershed were measured. The ?PAHs concentrations ranged from 539.0 to 6281.7 with the mean of 2214.8ng/g. The 2-3 rings PAHs, contributing 55 percent to ?PAHs, were the dominant species. Twenty-eight sites were grouped into three segments: Fenhe principal stream, estuaries of main branch streams, and Fenhe reservoir. ?PAHs was highest in the estuaries of main branch streams. The ecological risk assessment was studied by biological thresholds. The results showed levels of PAHs might cause mild but not acute adverse biological effects. In addition, PAHs ratios, PCA/MLR and hierarchical clustering analysis were applied to evaluate the possible sources. Coal combustion (35 percent), diesel and gasoline emissions (29 percent and 16 percent, respectively) might be the important sources. For sites in Fenhe reservoir, the major sources were complex, while other two segments were mainly influenced by coal combustion source. PMID:21903267

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

    PubMed

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

    2015-04-21

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

  1. Determination of polyoxymethylene (POM)--water partition coefficients for oxy-PAHs and PAHs.

    PubMed

    Josefsson, Sarah; Arp, Hans Peter H; Kleja, Dan Berggren; Enell, Anja; Lundstedt, Staffan

    2015-01-01

    Oxygenated polycyclic aromatic hydrocarbons (oxy-PAHs) are a class of ubiquitously occurring pollutants of which little is known. They can be co-emitted with PAHs or formed from PAHs in the environment. The environmental fate and risk of oxy-PAHs are difficult to assess due to a lack of methods to quantify their pore water concentrations. One sampler that can be used to determine freely dissolved concentrations of organic contaminants is polyoxymethylene (POM). In this study, POM - water partition coefficients (KPOM) were determined for 11 oxy-PAHs. KPOM values of 8 PAHs with similar hydrophobicities as the oxy-PAHs were determined for comparison. Results showed that logKPOM values ranged from 2.64 to 4.82 for the PAHs (2-4 rings), similar to previously determined values. LogKPOM values for investigated oxy-PAHs ranged from 0.96 to 5.36. The addition of carbonylic oxygen on a parent PAH generally lowered KPOM by 0.5 to 1.0 log units, which is attributable to the presence of carbonylic oxygens increasing water solubility. The KPOM values presented here will facilitate simultaneous assessments of freely dissolved water concentrations of oxy-PAHs and PAHs in environmental media. PMID:25460771

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

    PubMed

    Yang, Qin; Chen, Huaguo; Li, Baizhan

    2015-01-01

    Polycyclic aromatic hydrocarbons (PAHs) were analyzed for 136 indoor dust samples collected from Guizhou province, southwest of China. The ?18PAHs concentrations ranged from 2.18 ?gg-1 to 14.20 ?gg-1 with the mean value of 6.78 ?gg-1. The highest ?18PAHs concentration was found in dust samples from orefields, followed by city, town and village. Moreover, the mean concentration of ?18PAHs in indoor dust was at least 10% higher than that of outdoors. The 4-6 rings PAHs, contributing more than 70% of ?18PAHs, were the dominant species. PAHs ratios, principal component analysis with multiple linear regression (PCA-MLR) and hierarchical clustering analysis (HCA) were applied to evaluate the possible sources. Two major origins of PAHs in indoor dust were identified as vehicle emissions and coal combustion. The mean incremental lifetime cancer risk (ILCR) due to human exposure to indoor dust PAHs in city, town, village and orefield of Guizhou province, China was 6.1410-6, 5.0010-6, 3.0810-6, 6.0210-6 for children and 5.9210-6, 4.8310-6, 2.9710-6, 5.8110-6 for adults, respectively. PMID:25719362

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

    PubMed Central

    Li, Baizhan

    2015-01-01

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

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

    SciTech Connect

    Bernd R.T. Simoneit; Xinhui Bi; Daniel R. Oros; Patricia M. Medeiros; Guoying Sheng; Jiamo Fu

    2007-11-01

    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.

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

    PubMed

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

    2014-04-01

    We report the concentrations of 28 PAHs, 15 oxygenated PAHs (OPAHs) and 11 trace metals/metalloids (As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Se, and Zn) in muscle and gut+gill tissues of demersal fishes (Drapane africana, Cynoglossus senegalensis and Pomadasys peroteti) from three locations along the coast of the Gulf of Guinea (Ghana). The concentrations of ?28PAHs in muscle tissues averaged 192ngg(-1) dw (range: 71-481ngg(-1) dw) and were not statistically different between locations. The concentrations of ?28 PAHs were higher in guts+gills than in muscles. The PAH composition pattern was dominated by low molecular weight compounds (naphthalene, alkyl-naphthalenes and phenanthrene). All fish tissues had benzo[a]pyrene concentrations lower than the EU limit for food safety. Excess cancer risk from consumption of some fish was higher than the guideline value of 110(-6). The concentrations of ?15 OPAHs in fish muscles averaged 422ngg(-1) dw (range: 28-1715ngg(-1)dw). The ?15 OPAHs/?16 US-EPA PAHs concentration ratio was >1 in 68% of the fish muscles and 100% of guts+gills. The log-transformed concentrations of PAHs and OPAHs in muscles, guts+gills were significantly (p<0.05) correlated with their octanol-water partitioning coefficients, strongly suggesting that equilibrium partitioning from water/sediment into fish tissue was the main mechanism of bioaccumulation. The trace metal concentrations in the fish tissues were in the medium range when compared to fish from other parts of the world. The concentrations of some trace metals (Cd, Cu, Fe, Mn, Zn) were higher in guts+gills than in muscle tissues. The target hazard quotients for metals were<1 and did not indicate a danger to the local population. We conclude that the health risk arising from the consumption of the studied fish (due to their PAHs and trace metals content) is minimal. PMID:24486971

  6. Occupational PAH Exposures during Prescribed Pile Burns

    PubMed Central

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

    2008-01-01

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

  7. [Pollution Characteristics and Ecological Risk Assessment of PAHs in Water and Fishes from Daqing Lakes].

    PubMed

    Wang, Xiao-di; Zang, Shu-ying; Zhang, Yu-hong; Wang, Fan; Yang, Xing; Zuo, Yi-long

    2015-11-01

    The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) in 30 water samples and 5 tissues (gill, liver, brain, kidney and muscle) of 36 fishes which were collected from 18 typical lakes of the Daqing lakes group, China were measured between February and April 2012. The results of PAHs concentrations in the water showed that the range of total concentrations was 0.2-1.21 μg x L(-1) and the highest concentration was found in the Yueliangpao Lake. Clustering analysis of statistical method was used to classify the concentrations of PAHs in the water of 18 lakes, and PAHs source and evaluation of ecological risk in different lake groups were obtained respectively based on the analysis of PAHs ratio and the species sensitivity distributions method. The results of cluster analysis about PAHs concentrations in the water of 18 lakes showed that all the lakes were divided into 4 lake groups. Yueliangpao (YLP) and dongdahai (DDH) lakes were respectively divided into a separate group and the other 14 lakes were divided into two groups named XHH group and DQSK group. PAHs in the water of lakes were mainly from wood and coal burning except that the PAHs of the water in YLP group was caused by oil contamination. According to the surface water quality standard of the world and China, the concentrations of PAHs in the water of 4 lake groups all exceeded the standard variously. The PAHs concentrations of most water samples in YLP group and XHH group exceeded the 16 PAHs limit value of Environmental Protection Agency (US EPA) standard, especially, the concentration of Benz[a] pyrene with the strongest carcinogenicity of YLP group exceeded Chinese surface water quality standard. While in the DQSK lake group and the DDH lake group, several PAHs contaminations of water samples exceeded the standard. The tested and statistical results of 16 PAHs concentrations in 5 tissues of Cyprinus carpio and Hypophthalmichthys molitrix fish species in Daqing lakes showed the concentrations of anthracene in the gill tissue of Cyprinus carpio were significantly greater than those in the Hypophthalmichthys molitrix, while other 15 PAHs concentrations had no difference between the two species. Among the different tissues of Hypophthalmichthys molitrix or Cyprinus carpio, the concentrations of PAHs in the liver and kidney tissues which are the important tissues of PAHs accumulation were significantly greater than those in the muscle, gill and brain tissues of fish because of their pervasion ability of pollutants. The results of ecological risks of PAHs in water samples to different aquatic organism species and health risk of PAHs to human through the consumption of fish showed that low ecological risk to aquatic organism species and health risk of PAHs in the muscle of Hypophthalmichthys molitrix and Cyprinus carpio to human were observed in the 4 lake groups. PMID:26911021

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

    PubMed Central

    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

    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. PMID:23299301

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

    NASA Astrophysics Data System (ADS)

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

    2013-05-01

    This contribution documents the presence and possible origin of PAHs, their temporal concentration patterns and correlations with other air pollutants in the so-called Puebla-Tlaxcala valley. This valley is located to the east of the Mexico City Metropolitan Area and is a very populated region which suffers of air pollution problems. Emission sources of PAHs include open burning, industrial boilers, automobiles and trucks, but vehicle emissions vary significantly depending on the use of: fuel, engine type and catalytic converter. An important emission source in the Puebla-Tlaxcala region is wood burning for cooking. Therefore, it is expected to have contributions of PAHS from this type of sources. PAHs measurements were performed in an air pollution semi-rural receptor site (Chipilo) southwest the City of Puebla, using an aerosol photoelectric sensor (PAS 2000 CE) to measure the concentration of PAHs and a diffuser charger (DC 2000 CE) to evaluate the active surface (DC) of the particles. The measuring period included March and April of 2012 during the ozne season in central Mexico. The use of these two sensors in parallel has been identified as a fingerprint technique to identify different types of particles from several combustion processes and is a useful tool to identify quantitatively the major source of emissions, as well as to describe thephysical and chemical characteristics of the particles. Correlations between PAHs and DC, with NOx and CO, together with an analysis of atmospheric transport may approximate the possible origin of these particles. The coefficient PAHs / DC associated with backward trajectory analysis represents a tool to identify potential areas of emission. The correlation between PAHs and NOx emissions reflects association with diesel combustion, while the correlation between PAHs and CO, the combustion of gasoline. The results show that vehicle emissions are the major source of PAHs with an associated increase in the concentration of PAHs in the morning, when there is more vehicular traffic. The time series of PAHs also exhibit synchronized peaks of PAHs and DC that correspond to hours of traffic which shows the relationship of PAHs with DC. However, correlations of PAHs with DC show a relatively strong scattering suggesting that aerosols are a mixture of particles of different sources and different ages. Throughout the day is observed the aging of primary combustion particles due to the secondary aerosols coating. This coating may prolong the life time of the PAHs in the atmosphere. Also occurs a decrease in the ratio PAHs / DC during the day. Low ratios indicate the abundance of large particles, whereas high ratios indicate abundance dominated by small particle emissions from diesel engines. The resulting correlations show a significant linear trend evolution of PAHs with NOx, indicating that the PAHs are associated with the combustion of diesel, and a linear trend of PAHs with DC for each type of aerosol combustion, while the correlation of PAHs with CO results in an exponential trend which implies that PAHs are related to the combustion of diesel.

  10. Polycyclic aromatic hydrocarbons (PAHs) in the atmospheres of two French alpine valleys: sources and temporal patterns

    NASA Astrophysics Data System (ADS)

    Marchand, N.; Besombes, J. L.; Chevron, N.; Masclet, P.; Aymoz, G.; Jaffrezo, J. L.

    2004-08-01

    Alpine valleys represent some of the most important crossroads for international heavy-duty traffic in Europe, but the full impact of this traffic on air quality is not known due to a lack of data concerning these complex systems. As part of the program "Pollution des Valles Alpines" (POVA), we performed two sampling surveys of polycyclic aromatic hydrocarbons (PAHs) in two sensitive valleys: the Chamonix and Maurienne Valleys, between France and Italy. Sampling campaigns were performed during the summer of 2000 and the winter of 2001, with both periods taking place during the closure of the "Tunnel du Mont-Blanc". The first objective of this paper is to describe the relations between PAH concentrations, external parameters (sampling site localization, meteorological parameters, sources), and aerosol characteristics, including its carbonaceous fraction (OC and EC). The second objective is to study the capacity of PAH profiles to accurately distinguish the different emission sources. Temporal evolution of the relative concentration of an individual PAH (CHR) and the PAH groups BghiP+COR and BbF+BkF is studied in order to differentiate wood combustion, gasoline, and diesel emissions, respectively. The results show that the total particulate PAH concentrations were higher in the Chamonix valley during both seasons, despite the cessation of international traffic. Seasonal cycles, with higher concentrations in winter, are also stronger in this valley. During winter, particulate PAH concentration can reach very high levels (up to 155 ng.m-3) in this valley during cold anticyclonic periods. The examination of sources shows the impact during summer of heavy-duty traffic in the Maurienne valley and of gasoline vehicles in the Chamonix valley. During winter, Chamonix is characterized by the strong influence of wood combustion in residential fireplaces, even if the temporal evolution of specific PAH ratios are difficult to interpret. Information on sources given by PAH profiles can only be considered in qualitative terms.

  11. Properties of dust and PAHs in various environments of nearby galaxies

    NASA Astrophysics Data System (ADS)

    Kaneda, H.

    In star-forming regions, dust and polycyclic aromatic hydrocarbons (PAHs) absorb a significant fraction of stellar ultraviolet (UV) photons and re-radiate them in the infrared (IR). Hence the IR luminosities due to dust and PAH emission are both powerful tools to trace star-forming activities in galaxies. However they are not merely tracers of star-formation activity. Spectral information on the dust and PAH emission would have much deeper physical implications for understanding the properties of the ISM. External galaxies provide us with a much wider range of the ISM physical conditions than our Galaxy. For example, Spitzer mid-IR spectroscopy has shown a variety of the PAH emission features for various types of galaxies, which reflects significant changes in the properties of PAHs, such as an ionization state and a size distribution. AKARI near-IR spectroscopy has revealed spatial variations in the intensity ratio of the aromatic to the aliphatic hydrocarbon spectral feature in galaxies, indicating structural changes of carbonaceous grains in shocked regions. The relation of PAH to far-IR dust is another important probe to study the conditions of the interstellar environments. In general, PAHs and far-IR dust are mixed well in the ISM, producing global correlations between their IR luminosities. In local areas within a galaxy, however, their abundance ratios are expected to vary substantially due to interactions with interstellar shocks, hard UV radiation fields and diffuse X-ray hot plasmas. Until recently, spatial resolutions in the far-IR were extremely poor compared with those in the near- and mid-IR. Herschel now enables us to make a detailed comparison of the spatial distributions of far-IR dust and PAH emission within a galaxy. This paper reviews recent observational results on the IR emission properties of dust and PAHs exposed to various environments of nearby galaxies, which range from passive elliptical galaxies to starburst galaxies with galactic superwinds, and (ultra-)luminous infrared galaxies. In particular, the paper focuses on variations in the PAH spectral features and PAH to far-IR dust ratios to discuss their implications for the processing of carbonaceous grains in harsh interstellar environments to understand the fate of dust processed by shocks and radiation through the evolution of galaxies.

  12. Cosolubilization synergism occurrence in codesorption of PAH mixtures during surfactant-enhanced remediation of contaminated soil.

    PubMed

    Liang, Xujun; Guo, Chuling; Wei, Yanfu; Lin, Weijia; Yi, Xiaoyun; Lu, Guining; Dang, Zhi

    2016-02-01

    Surfactant-enhanced remediation (SER) has been widely applied in decontaminating PAH-polluted soil. Most researches focus on evaluating washing efficiency without considering pollutants' mutual interaction. This study aims to investigate cosolubilization effect between phenanthrene (Phe) and pyrene (Pyr) in nonionic surfactant Triton X-100 (TX100) solution on their codesorption performance from soil. Cosolubilization experiment showed that, when cosolubilized, solubility of Phe and Pyr in TX100 increased by 15.38% and 18.19%, respectively, as quantified by the deviation ratio of molar solubilization ratio in single and binary solute solubilization systems. The synergism may be due to the enlarged micelle volume caused by PAHs solubilized in the shell region of the micelle. The cosolubilization effect was further observed in the soil washing process. The strengthened TX100 solubilization capacity towards Phe and Pyr could increase the two PAHs' codesorption efficiency from soil, accompanied by synergistic extent of 6-15%. However, synergism in codesorption was weaker than that observed in the cosolubilization system, which may be related to surfactant loss to soil and PAH partition into soil organic matter and the sorbed surfactants. The improved remediation performance during codesorption of mixed PAHs implies the significance of combining PAHs' mutual interaction into evaluating SER, which may reduce the surfactant washing concentration and save remediation cost. PMID:26397474

  13. Pavement Sealcoat, PAHs, and the Environment

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

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

  14. C2D Spitzer-IRS spectra of disks around T Tauri stars. II. PAH emission features

    NASA Astrophysics Data System (ADS)

    Geers, V. C.; Augereau, J.-C.; Pontoppidan, K. M.; Dullemond, C. P.; Visser, R.; Kessler-Silacci, J. E.; Evans, N. J., II; van Dishoeck, E. F.; Blake, G. A.; Boogert, A. C. A.; Brown, J. M.; Lahuis, F.; Mern, B.

    2006-11-01

    Aims.We search for Polycyclic Aromatic Hydrocarbon (PAH) features towards young low-mass (T Tauri) stars and compare them with surveys of intermediate mass (Herbig Ae/Be) stars. The presence and strength of the PAH features are interpreted with disk radiative transfer models exploring the PAH feature dependence on the incident UV radiation, PAH abundance and disk parameters. Methods: .Spitzer Space Telescope 5-35 ?m spectra of 54 pre-main sequence stars with disks were obtained, consisting of 38 T Tauri, 7 Herbig Ae/Be and 9 stars with unknown spectral type. Results: .Compact PAH emission is detected towards at least 8 sources of which 5 are Herbig Ae/Be stars. The 11.2 ?m PAH feature is detected in all of these sources, as is the 6.2 ?m PAH feature for the 4 sources for which short wavelength data are available. However, the 7.7 and 8.6 ?m features appear strongly in only 1 of these 4 sources. Based on the 11.2 ?m feature, PAH emission is observed towards at least 3 T Tauri stars, with 14 tentative detections, resulting in a lower limit to the PAH detection rate of 8%. The lowest mass source with PAH emission in our sample is T Cha with a spectral type G8. All 4 sources in our sample with evidence for dust holes in their inner disk show PAH emission, increasing the feature/continuum ratio. Typical 11.2 ?m line intensities are an order of magnitude lower than those observed for the more massive Herbig Ae/Be stars. Measured line fluxes indicate PAH abundances that are factors of 10-100 lower than standard interstellar values. Conversely, PAH features from disks exposed to stars with T_eff? 4200 K without enhanced UV are predicted to be below the current detection limit, even for high PAH abundances. Disk modeling shows that the 6.2 and 11.2 ?m features are the best PAH tracers for T Tauri stars, whereas the 7.7 and 8.6 ?m bands have low feature over continuum ratios due to the strongly rising silicate emission.

  15. Effect of land use activities on PAH contamination in urban soils of Rawalpindi and Islamabad, Pakistan.

    PubMed

    Ud Din, Ikhtiar; Rashid, Audil; Mahmood, Tariq; Khalid, Azeem

    2013-10-01

    Urbanization can increase the vulnerability of soils to various types of contamination. Increased contamination of urban soils with polycyclic aromatic hydrocarbon (PAH) could relate to increased number of petrol pump stations and mechanical workshops-a phenomenon that needs to be constantly monitored. This study was undertaken to explore the soil PAH levels in Rawalpindi and Islamabad urban areas in relation to land use activities. Composite soil samples from petrol pump stations and mechanical workshops (n?=?32) areas were evaluated for five PAHs--naphthalene, phenanthrene, pyrene, benzo[a]pyrene, and indeno(1,2,3-cd)pyrene-and compared with control area locations with minimum petroleum-related activity (n?=?16). Surface samples up to 3cm depth were collected and extraction of analytes was carried out using n-hexane and dichloromethane. Prior to running the samples, standards (100?gml(-1)) were run on HPLC to optimize signal to noise ratio using acetonitrile as mobile phase at a flow rate of 1.25ml/min at 40C. Significant differences between petrol pump stations and mechanical workshop areas were observed for individual PAH as well as with control area soil samples. Naphthalene was found to be the most abundant PAH in soil, ranging from 2.47 to 24.36mgkg(-1). Correlation between the benzo[a]pyrene (BaP) level in soil and the total PAH concentration (r?=?0.82, P?PAH pollution. A clear segregation between petrogenic and pyrogenic sources of contamination was observed when low molecular weight PAHs detected in soil was plotted against high molecular weight PAHs. The former source comprised lubricants and used engine oil found at mechanical workshops, whereas the latter could be mostly attributed to vehicular emission at petrol pumps. The results indicate that PAH contamination in urban areas of Rawalpindi and Islamabad has direct relevance with land use for petroleum activity. We conclude that in order to reduce the soil PAH exposure in urban environment, petrol pumps and mechanical workshops must be shifted to less densely populated areas because of their role as important point sources for PAH emission. PMID:23595691

  16. Developing PAHs as Probes of Physical Conditions: Fitting PAH Spectra with the Ames PAH IR Spectral Database

    NASA Astrophysics Data System (ADS)

    Allamandola, Louis

    It is quite clear from the Infrared Space Observatory (ISO) and Spitzer Space Telescope results that we live in a molecular universe and that the mid-infrared is aglow in emission from polycyclic aromatic hydrocarbons (PAHs). Observationally, PAHs are easily identified by their characteristic emission spectrum, they are intrinsically strong emitters, and they dominate the emission in star forming galaxies in the mid-infrared, comprising 10-20% of the energy emitted in the infrared. These characteristics make them useful probes even for distant objects. The exceptional spectra provided by the ISO and Spitzer observatories have revealed in detail how the PAH features vary between different classes of objects and spatially within extended objects, showing that the details in the emission spectrum depend on the specific PAH molecules present, their size, ionization state, structure etc., and therefore reflect conditions within the emission zones. Thus, understanding the origin and evolution of this important family of molecules, how they interact with and control their environment, and how the details in their emission spectra reflect local conditions, is a fundamental goal of astrophysics. Advances in laboratory studies and computer-based calculations of PAHs now allow us to delve into the details of PAH spectral behavior seen by both ISO and Spitzer. We propose to model PAH spectra observed in reflection nebulae, HII regions, planetary nebulae, YSOs, AGB stars, and galaxies using laboratory and theoretically generated spectra from the NASA Ames PAH IR Spectroscopic Database to advance our understanding of the factors that determine the PAH spectra that we see in objects both near and far.

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

    PubMed

    Wu, Guozhong; Li, Xingang; Kechavarzi, Cdric; Sakrabani, Ruben; Sui, Hong; Coulon, Frdric

    2014-07-01

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

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

    PubMed

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

    2011-04-01

    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

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

    ERIC Educational Resources Information Center

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

    2013-01-01

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

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

    PubMed

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

    2011-08-15

    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

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

    PubMed Central

    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

    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 ΣNPAH and ΣOPAH 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. PMID:21766847

  2. Diurnal and nocturnal measurements of PAH, nitro-PAH, and oxy-PAH compounds in atmospheric particulate matter of a sugar cane burning region

    NASA Astrophysics Data System (ADS)

    Souza, Kely F.; Carvalho, Lilian R. F.; Allen, Andrew G.; Cardoso, Arnaldo A.

    2014-02-01

    Polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs, and oxy-PAHs were studied in the atmospheric particulate matter of a subtropical rural region (São Paulo State, Brazil) affected by emissions from sugar cane burning. Diurnal and nocturnal samples were collected from May to June of 2010. In general, average PAH concentrations were significantly higher at night, suggesting that the compounds were predominantly emitted to the atmosphere during biomass burning (which was mainly performed at night). The maximum average PAH concentration was found for benzo[b]fluoranthene at night (2.9 ± 5.4 ng m-3). Among the nitro-PAH compounds, the highest average concentrations were obtained for 9-nitrophenanthrene in diurnal and nocturnal samples (1.5 ± 1.2 and 1.3 ± 2.1 ng m-3, respectively). In contrast to the PAH and nitro-PAH compounds, the oxy-PAHs could not be directly associated with sugar cane burning. The most abundant oxy-PAH compound was benzanthrone (1.6 ± 1.3 ng m-3) at night, followed by 9,10-anthraquinone (1.1 ± 0.9 ng m-3) and 9-fluorenone (0.4 ± 0.1 ng m-3) during the day. A correlation matrix was used to explore the origins of the different compounds. The data suggested that during the daytime, direct emissions (mainly in vehicle exhaust) contributed to the presence of PAHs, nitro-PAHs, and oxy-PAHs in air. Photochemical production also appeared to be a source of the majority of nitro-PAHs and oxy-PAHs, while photolysis could have contributed to removal of the nitro-PAHs during the daytime. At night, sugar cane burning emissions were the primary source of the PAHs and nitro-PAHs, with additional sources also contributing to the levels of oxy-PAHs in the atmosphere.

  3. Determination of some carcinogenic PAHs with toxic equivalency factor along roadside soil within a fast developing northern city of India

    NASA Astrophysics Data System (ADS)

    Kumar, A. Vaneet; Kothiyal, N. C.; Kumari, Saruchi; Mehra, R.; Parkash, A.; Sinha, R. R.; Tayagi, S. K.; Gaba, R.

    2014-04-01

    The objective of the present study was to ascertain contamination levels, distribution behaviour and PAHs exposure during summer, winter and autumn during 2011-2012 in one of the developing cities of northern India. Average PAHs concentration was found to be 18.17, 4.04 and 16.38 ?g g -1, whereas, concentration of 16 individual PAHs was found to vary between 0.02 and 200.23, 0.008 and 28.4 ?g g -1, and 0.01 and 252.55 ?g g -1 during summer, winter and autumn seasons, respectively. The average concentration of low and high carcinogenic PAHs during summer, winter and autumn was found to be 5.1 and 31.29, 2.1 and 6.4, 4.74 and 35.08 ?g g -1 at most intercepts. The average ratio of low to high carcinogenic PAHs was found to be 1:6, 1:3, 1:7.6 during summer, winter and autumn, respectively. Five ringed PAHs were found in higher concentration in all seasons. Dib(ah)A and B(a)P were the two individual PAHs found in highest concentration during summer, winter and autumn seasons. Two tailed T-test was applied for authenticity of the results. Toxic equivalency factor of B(a)P and Dib(ah)A was maximum as compared to other PAHs. The study could be of great significance for the planners while considering environmental remedial measures.

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  5. Urban sprawl leaves its PAH signature

    USGS Publications Warehouse

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

    2000-01-01

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

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

    PubMed

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

    2013-04-15

    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

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

    PubMed Central

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

    2011-01-01

    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. PMID:21422231

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

    PubMed

    Tuncel, Semra G; Topal, Tansel

    2015-03-01

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

  9. Climate change and emissions impacts on atmospheric PAH transport to the Arctic.

    PubMed

    Friedman, Carey L; Zhang, Yanxu; Selin, Noelle E

    2014-01-01

    We investigate effects of 2000-2050 emissions and climate changes on the atmospheric transport of three polycyclic aromatic hydrocarbons (PAHs): phenanthrene (PHE), pyrene (PYR), and benzo[a]pyrene (BaP). We use the GEOS-Chem model coupled to meteorology from a general circulation model and focus on impacts to northern hemisphere midlatitudes and the Arctic. We project declines in anthropogenic emissions (up to 20%) and concentrations (up to 37%), with particle-bound PAHs declining more, and greater declines in midlatitudes versus the Arctic. Climate change causes relatively minor increases in midlatitude concentrations for the more volatile PHE and PYR (up to 4%) and decreases (3%) for particle-bound BaP. In the Arctic, all PAHs decline slightly under future climate (up to 2%). Overall, we observe a small 2050 "climate penalty" for volatile PAHs and "climate benefit" for particle-bound PAHs. The degree of penalty or benefit depends on competition between deposition and surface-to-air fluxes of previously deposited PAHs. Particles and temperature have greater impacts on future transport than oxidants, with particle changes alone accounting for 15% of BaP decline under 2050 emissions. Higher temperatures drive increasing surface-to-air fluxes that cause PHE and PYR climate penalties. Simulations suggest ratios of more-to-less volatile species can be used to diagnose signals of climate versus emissions and that these signals are best observed in the Arctic. PMID:24279957

  10. Carcinogenic potential of PAHs in oil-contaminated soils from the main oil fields across China.

    PubMed

    Wang, Jie; Cao, Xiaofeng; Liao, Jingqiu; Huang, Yi; Tang, Xiaoyan

    2015-07-01

    The concentrations, composition profiles, and sources of polycyclic aromatic hydrocarbons (PAHs) were analyzed in 55 surface soil samples collected from four oil fields across China (Daqing, DQ; Shengli, SL; Xinjiang, XJ; and Huabei, HB). The total 16 priority PAHs concentrations of DQ, SL, XJ, and HB ranged from 857 to 27,816; 480 to 20,625; 497 to 43,210; and 12,112 to 45,325 ng/g, respectively, with means of 9160; 6394; 13,569; and 22,954 ng/g and the seven possible carcinogenic PAHs accounted for 8-25.7 % of the total PAHs. Almost all the samples were heavily contaminated, and phenanthrene, chrysene, and pyrene were the most dominant components. The PAH isomeric ratios indicated that PAHs in oil fields mainly originated from petroleum. The toxic assessment illustrated that people living and working in oil fields would suffer low carcinogenic risk, which was somehow coincided with the results of epidemiological survey on cancer incidence. It seems essential to pay more attention to the chronic human health effects of exposure to oil fields and to focus new studies on the public health field that involves a large number of people all over the world. PMID:25772862

  11. SOA Formation from Photooxidation of Individual PAHs and Mixtures

    NASA Astrophysics Data System (ADS)

    Chen, C. L.; Kacarab, M.; Tang, P.; Cocker, D. R., III

    2014-12-01

    Individual SOA experiments on PAHs such as naphthalene and methylnaphthalenes were conducted at the UCR CE-CERT environmental chamber. Measurements were made with a suite of instrumentation that includes HR-ToF-AMS, VTDMA, and APM-SMPS to comprehensively understand the chemical composition characteristics, volatility and density of particles. Our results indicated that the SOA yield from PAHs is large and the elemental and chemical composition analysis of HR-ToF-AMS revealed that oxygen-to-carbon ratio (O/C) increases with oxidation time and also suggested that the SOA from these three PAHs are mostly low volatility OOA. The density of aerosol formed from 1-methylnaphthalene photooxidation under high NOx condition was observed to decrease from 1.5 g/cm3 to 0.7 g/cm3 during the course of experiment. Transmission electron microscopy (TEM) of 1-methylnaphthalene SOA showed that the SOA coagulated after 5~6 hours photooxidation to form fractal-like particles. The sensitivity of SOA formation to varying HC mixtures is further explored. Serial mixtures of PAHs photooxidation experiments were conducted, including naphthalene, 1-methylnapthalene, 2-methylnaphtalene with m-xylene, and/or the surrogate mixture used to develop the Carter O3 reactivity scales. Preliminary results show that the SOA formation from m-xylene and naphthalene mixture photooxidation was found to be suppressed by m-xylene, and the volatility measured as volume remaining fraction (VRF) of the m-xylene and naphthalene mixture increases from 0.2 to 0.4, which indicates the volatility of mixture SOA is dominated by m-xylene SOA.

  12. [Influences of pine needles physiological properties on the PAH accumulation].

    PubMed

    Yang, Ping; Wang, Zhen; Chen, Jing-Wen; Tian, Fu-Lin; Ge, Lin-Ke

    2008-07-01

    The lipid contents, specific surface areas and stomata density of two kinds of pine (Cedrus deodar and Pinus thunbergii) needles were determined simultaneously with the levels of polycyclic aromatic hydrocarbons (PAHs). The influences of the physiological properties of two species on the accumulation of PAHs in pine needles were investigated. The PAH concentrations in Cedrus deodar needles are higher than that in Pinus thunbergii needles, and the average total PAH concentrations (PAHs) in two species are (1 101 +/- 692) ng/g and (518 +/- 339) ng/g, respectively. The capabilities of accumulating PAHs for two species are different. The lipid content is the principal factor influencing the levels of pine needle PAHs. In Cedrus deodar and Pinus thunbergii needles, 3-ring (> 56%) and 4-ring (> 31%) PAHs make up large proportions of sigma PAHs. The accumulation capabilities of pine needles for 3-ring PAHs are greater than 4-ring PAHs, and the concentrations of 3-ring PAHs are about two times of those of 4-ring PAHs. There are no significant correlations between the levels of 5- and 6-ring PAHs and lipid contents for two species. For two species, the correlations between lipid contents and specific surface areas are different, which results in the contrary correlations between the PAH levels and specific surface areas for Cedrus deodar and Pinus thunbergii. Specific surface areas and stomata density affect the levels of 5- and 6-ring PAHs in pine needles significantly. PMID:18828394

  13. PAH in the laboratory and interstellar space

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

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

  14. Amphibian responses to photoinduced toxicity of PAHs

    SciTech Connect

    Hatch, A.C.; Burton, G.A. Jr.

    1995-12-31

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

  15. SOURCES OF HUMAN EXPOSURE TO AIRBORNE PAH

    EPA Science Inventory

    Personal exposures to airborne particulate polycyclic aromatic hydrocarbons (PAHs) were studied in several populations in the US, Japan, and Czech Republic. Personal exposure monitors, developed for human exposure biomonitoring studies were used to collect fine particles (<_ 1....

  16. Isolation of Adherent Polycyclic Aromatic Hydrocarbon (PAH)-Degrading Bacteria Using PAH-Sorbing Carriers

    PubMed Central

    Bastiaens, Leen; Springael, Dirk; Wattiau, Pierre; Harms, Hauke; deWachter, Rupert; Verachtert, Hubert; Diels, Ludo

    2000-01-01

    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 Mycobacterium 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. PMID:10788347

  17. Metabolomic analysis to define and compare the effects of PAHs and oxygenated PAHs in developing zebrafish.

    PubMed

    Elie, Marc R; Choi, Jaewoo; Nkrumah-Elie, Yasmeen M; Gonnerman, Gregory D; Stevens, Jan F; Tanguay, Robert L

    2015-07-01

    Polycyclic aromatic hydrocarbons (PAHs) and their oxygenated derivatives are ubiquitously present in diesel exhaust, atmospheric particulate matter and soils sampled in urban areas. Therefore, inhalation or non-dietary ingestion of both PAHs and oxy-PAHs are major routes of exposure for people; especially young children living in these localities. While there has been extensive research on the parent PAHs, limited studies exist on the biological effects of oxy-PAHs which have been shown to be more soluble and more mobile in the environment. Additionally, investigations comparing the metabolic responses resulting from parent PAHs and oxy-PAHs exposures have not been reported. To address these current gaps, an untargeted metabolomics approach was conducted to examine the in vivo metabolomic profiles of developing zebrafish (Danio rerio) exposed to 4 M of benz[a]anthracene (BAA) or benz[a]anthracene-7,12-dione (BAQ). By integrating multivariate, univariate and pathway analyses, a total of 63 metabolites were significantly altered after 5 days of exposure. The marked perturbations revealed that both BAA and BAQ affect protein biosynthesis, mitochondrial function, neural development, vascular development and cardiac function. Our previous transcriptomic and genomic data were incorporated in this metabolomics study to provide a more comprehensive view of the relationship between PAH and oxy-PAH exposures on vertebrate development. PMID:26001975

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

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

  19. Properties of polycyclic aromatic hydrocarbons in the northwest photon dominated region of NGC 7023. II. Traditional PAH analysis using k-means as a visualization tool

    SciTech Connect

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

    2014-11-10

    Polycyclic aromatic hydrocarbon (PAH) emission in the Spitzer-IRS spectral map of the northwest photon dominated region (PDR) in NGC 7023 is analyzed using the 'traditional' approach in which the PAH bands and plateaus between 5.2-19.5 μm are isolated by subtracting the underlying continuum and removing H{sub 2} emission lines. The spectra are organized into seven spectroscopic bins by using k-means clustering. Each cluster corresponds to, and reveals, a morphological zone within NGC 7023. The zones self-organize parallel to the well-defined PDR front that coincides with an increase in intensity of the H{sub 2} emission lines. PAH band profiles and integrated strengths are measured, classified, and mapped. The morphological zones revealed by the k-means clustering provides deeper insight into the conditions that drive variations in band strength ratios and evolution of the PAH population that otherwise would be lost. For example, certain band-band relations are bifurcated, revealing two limiting cases; one associated with the PDR, the other with the diffuse medium. Traditionally, PAH band strength ratios are used to gain insight into the properties of the emitting PAH population, i.e., charge, size, structure, and composition. Insights inferred from this work are compared and contrasted to those from Boersma et al. (first paper in this series), where the PAH emission in NGC 7023 is decomposed exclusively using the PAH spectra and tools made available through the NASA Ames PAH IR Spectroscopic Database.

  20. PAH Emission in the Orion Bar

    NASA Technical Reports Server (NTRS)

    Bregman, Jesse; Sloan, G. C.

    1996-01-01

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

  1. Developing strategies for PAH and TCE bioremediation

    SciTech Connect

    Mahaffey, W.R.; Nelson, M.; Kinsella, J. ); Compeau, G. )

    1991-10-01

    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.

  2. PAHFIT: Properties of PAH Emission

    NASA Astrophysics Data System (ADS)

    Smith, J. D.; Draine, Bruce

    2012-10-01

    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.

  3. Long term observations of PM2.5-associated PAHs: Comparisons between normal and episode days

    NASA Astrophysics Data System (ADS)

    Wang, Jia; Li, Xiao; Jiang, Nan; Zhang, Wenkai; Zhang, Ruiqin; Tang, Xiaoyan

    2015-03-01

    The pollution characteristic of fine particular matter (PM2.5) and associated polycyclic aromatic hydrocarbons (PAHs) are currently drawing a great deal of interest because of their influence on environment and health. In this study, PM2.5 was collected from 2011 to 2013 (n = 188) in a suburban area of Zhengzhou, China. 16-PAHs were analyzed to determine the concentration, seasonal variation and potential sources during normal days and episode events. The total mass of 16 PAHs and PM2.5 were in the range of 7-961 ng m-3 and 55-697 μg m-3, with a 3-year average of 174 ng m-3 and 194 μg m-3 respectively. Winter is most polluted for both PM2.5 and PAHs. Average PAH and PM2.5 concentrations during three episode events are 454 ng m-3 and 453 μg m-3, respectively, much higher than values during normal days (299 ng m-3 and 180 μg m-3, respectively). Ratios of Σ16PAH/PM2.5 varied with seasons and concentrations of PM2.5, but showed a negative correlation with PM2.5 concentrations during episode events. The dominant components of PAHs are Benzo[b]fluoranthene, Chrysene, Fluoranthene, and Benzo[k]fluoranthene, Benz[a]anthracene, Pyrene, Indeno(1,2,3-cd)pyrene and their total concentrations vary from 27 to 342 ng m-3, accounting for 58-82% (average = 73%) of 16 PAHs. The Benzo[a]pyrene (Bap) concentration obtained was 9.4 ng m-3 (3-year average), exceeding nearly one order of magnitude of ambient air BaP standard (annual average: 1.0 ng m-3) in China. Diagnose ratios and Positive Matrix Factorization results show that coal combustion, vehicles, coking plant, and biomass burning are main sources for PAHs in this area. The high concentrations of PM2.5 and PAHs, especially during episode events, reflected a potential health problem for nearby public and the necessity of air pollution control for both stationary and mobile sources.

  4. Biomarkers of PAH exposure in fish

    SciTech Connect

    Lewis, J.; Robinson, R.; Solomon, K.; Hodson, P.; Rao, S.; Day, K.

    1995-12-31

    Many polycyclic aromatic hydrocarbons (PAHs) are mutagenic and carcinogenic, and some may cause reproductive toxicity in fish. The purpose of this study is to develop biomarkers of PAH effects on fathead minnows (P. promelas). Mesocosms will be treated with the wood preservative creosote (composition is ca. 80% as PAHs). The authors anticipate that metabolism of PAHs by fish will generate free radicals that damage DNA and cause liver tumors. Rainbow trout (RBT) (0. mykiss) and fathead minnows (FHM) will be exposed to a range of waterborne creosote concentrations below the LC,, values (5.66 mg/L for RBT and 5.97 mg/L for FHM). Fish liver, muscle, intestine, and bile will be removed to measure (1) PAH biotransformation (EROD activity and concentration of PAH metabolites in bile), (2) oxidative stress (retinoic acid, glutathione peroxidase, and lipid hydroperoxide levels), and (3) genotoxicity (micronucleus induction, DNA strand breaks, and DNA adducts). Biomarkers will be considered suitable for application when results are repeatable, show exposure dependency, and respond at sublethal concentrations typical of contaminated ecosystems.

  5. Mycoremediation of PAH-contaminated soil.

    PubMed

    Bhatt, M; Cajthaml, T; Sasek, V

    2002-01-01

    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

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

    SciTech Connect

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

    2012-10-15

    Radial profiles of electron temperature and density are measured at high spatial ({approx}1 mm) and temporal ( Greater-Than-Or-Slanted-Equal-To 10 {mu}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 ( Less-Than-Or-Equivalent-To 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.

  7. Remedial effects of Potamogeton crispus L. on PAH-contaminated sediments.

    PubMed

    Meng, Fanbo; Huang, Jianjun; Liu, Hongyan; Chi, Jie

    2015-05-01

    In this study, the remedial effects of submerged macrophyte Potamogeton crispus L. on polycyclic aromatic hydrocarbon (PAH)-contaminated sediments were investigated. After a 54-day experiment, the dissipation ratios of phenanthrene and pyrene were 84.8-88.3 and 72.4-78.5% in rhizosphere sediments, which were significantly higher than those in non-rhizosphere sediments (54.2-66.6 and 54.7-58.5%). The dissipation increment increased not only with increasing spiked concentration, but also over time, while plant uptake accounted for only a small portion (<6%) of the dissipation increment. Moreover, bioavailable fraction tests revealed that biodegradation was not controlled by the amount of bioavailable PAHs. For better understanding of the microbial mechanism involved, phospholipid fatty acid (PLFA) profiles were analyzed. Biomass of microorganisms indicated by the total PLFA content was higher in rhizosphere sediments than in non-rhizosphere sediments and was related well to the dissipation ratios of the two PAHs. Cluster analysis showed that community structure significantly changed in rhizosphere sediments. Moreover, the increments of PAH dissipation in rhizosphere sediments had a strong positive correlation with those of polyphenol oxidase activities in the same media. It can be concluded that the enhanced remediation of PAHs by P. crispus was mainly due to the increase of microbial biomass and activity as well as changes of microbial community structure in sediments as a result of plant growth stimulation. PMID:25752637

  8. Concentrations and spatial distribution of polycyclic aromatic hydrocarbons (PAHs) and nitrated PAHs (NPAHs) in the atmosphere of North China, and the transformation from PAHs to NPAHs.

    PubMed

    Lin, Yan; Qiu, Xinghua; Ma, Yiqiu; Ma, Jin; Zheng, Mei; Shao, Min

    2015-01-01

    The occurrence of polycyclic aromatic hydrocarbons (PAHs) and nitrated derivatives (NPAHs), as well as their transformation may have significant health impacts on humans. To investigate the level, spatial distribution and the transformation process of PAHs and NPAHs in North China, we performed a griddedfield passive air sampling campaign in summer of 2011. The median concentration of 25 PAH congeners and 13 NPAHs was 294 ng m(-3) (or 26.7 mg sample(-1)) and 203 ng sample(-1), respectively. Relative higher level of PAHs in Shanxi Province and NPAHs in megacities was observed. In North China, coal/biomass combustion and photochemical formation was the predominant source of PAHs and NPAHs, respectively.To investigate the relationship between these pollutants, a model incorporating NPAHs, PAHs and NO(2) was established, and the result indicated that NO(2) will promote the transformation processes from PAHs to NPAHs, which may increase the total toxicity of PAH-NPAH mixtures. PMID:25463710

  9. Theoretical study of deuteronated PAHs as carriers for IR emission features in the ISM

    NASA Astrophysics Data System (ADS)

    Buragohain, Mridusmita; Pathak, Amit; Sarre, Peter; Onaka, Takashi; Sakon, Itsuki

    2015-11-01

    This work proposes deuteronated PAH (DPAH+) molecules as a potential carrier of the 4.4 and 4.65 μm mid-infrared emission bands that have been observationally detected towards the Orion and M17 regions. Density Functional Theory calculations have been carried out on DPAH+ molecules to see the variations in the spectral behaviour from that of a pure polycyclic aromatic hydrocarbon (PAH). DPAH+ molecules show features that arise due to the stretching of the aliphatic C-D bond. Deuterated PAHs have been previously reported as carriers for such features. However, preferred conditions of ionization of PAHs in the interstellar medium (ISM) indicates the possibility of the formation of DPAH+ molecules. Comparison of band positions of DPAH+s shows reasonable agreement with the observations. We report the effect of size of the DPAH+ molecules on band positions and intensities. This study also reports a D/H ratio ([D/H]_{sc}; the ratio of C-D stretch and C-H stretch bands per [D/H]_{num}) that is decreasing with the increasing size of DPAH+s. It is noted that large DPAH+ molecules (no. of C atoms ˜50) match the D/H ratio that has been estimated from observations. This ratio offers prospects to study the deuterium abundance and depletion in the ISM.

  10. Performance of PAHs emission from bituminous coal combustion.

    PubMed

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

    2004-12-01

    Carcinogenic and mutagenic polycyclic aromatic hydrocarbons (PAHs) generated in coal combustion have caused great environmental health concern. Seventeen PAHs (16 high priority PAHs recommended by USEPA plus Benzo[e]pyrene) present in five raw bituminous coals and released during bituminous coal combustion were studied. The effects of combustion temperature, gas atmosphere, and chlorine content of raw coal on PAHs formation were investigated. Two additives (copper and cupric oxide) were added when the coal was burned. The results indicated that significant quantities of PAHs were produced from incomplete combustion of coal pyrolysis products at high temperature, and that temperature is an important causative factor of PAHs formation. PAHs concentrations decrease with the increase of chlorine content in oxygen or in nitrogen atmosphere. Copper and cupric oxide additives can promote PAHs formation (especially the multi-ring PAHs) during coal combustion. PMID:15547964

  11. 13CO2/12CO2 ratio analysis in exhaled air by lead-salt tunable diode lasers for noninvasive diagnostics in gastroenterology

    NASA Astrophysics Data System (ADS)

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

    1999-07-01

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

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

    PubMed

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

    2014-06-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2003-04-01

    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.

  14. A Search for PAHs in Astrophysical Environments

    NASA Technical Reports Server (NTRS)

    Salama, F.; Cami, J.; Tan, X.; Biennier, L.

    2005-01-01

    We present the results of a dedicated search for the spectral signatures in the visible range of neutral polycyclic aromatic hydrocarbons (PAHs) in astronomical observations representing various astrophysical environments, probing a total column of line of sight material corresponding to Av=50. Laboratory measurements of PAHs in simulated astrophysical conditions are now available (see contribution of Salama et al.) which provide for the first time the exact wavelengths for the spectral features of these molecules, as well as detailed information on the intrinsic line profiles and oscillator strengths. These measurements therefore allow a direct comparison to astronomical observations and an estimate of, or upper limit to, the abundance of individual PAHs in space. As the column densities for individual PAHs in interstellar or circumstellar lines of sight are expected to be very low, such a comparison and analysis requires astronomical observations at very high signal to noise. We present such a data set here for lines of sight representing diffuse clouds and circumstellar environments of carbon stars, and their comparison with gas phase spectra of a representative set of free, cold PAHs.

  15. Patterns of changes and diagnostic values of FEF50%, FEF25%–75% and FEF50%/FEF25%–75% ratio in patients with varying control of bronchial asthma

    PubMed Central

    Lutfi, Mohamed Faisal

    2016-01-01

    Background The pattern of change in FEF50%, FEF25%–75% and FEF50%/FEF25%–75% ratio depends on mechanics of forceful expiration, provided that non-homogenous lung emptying is faithfully recorded in the expiratory flow-volume loops. Objective To assess the potential clinical value of FEF50%, FEF25%–75% and FEF50%/FEF25%–75% ratio as an indicator of bronchial asthma (BA) control. Methodology The study involved 75 patients with BA matched for age and gender with 45 non-asthmatic subjects. Based on asthma control test (ACT) and spirometry, asthmatic patients were subdivided into controlled and poorly controlled/uncontrolled. The relationship between FEF50% and FEF25%–75% as well as FEF50%/FEF25%–75% ratio and ACT score were assessed using linear regression. ROC curves were used to assess reliability of FEF25%–75% and FEF50% to diagnose BA in patients with different degree of asthma control. Results FEF50% correlated strongly with FEF25%–75% (r = 0.989, P < 0.001) and the relationship between the two indices is governed by the formula FEF50% = 1.132* FEF25%–75% – 0.003. There was no significant correlation (r = − 0.159, P = 0.083) between FEF50%/FEF25–75% ratio and ACT score. The diagnostic capability of FEF25%–75% for spirometric diagnosis of BA is only marginally better compared to FEF50% (area under ROC curves were 0.88 and 0.89 respectively, P < 0.001); however, diagnostic power of both spirometric indices deceased with poor BA control. Conclusion FEF50%/FEF25%–75% has no clinical value as an indicator for BA control. Role of FEF25%–75% in evaluation of BA is marginally better than FEF50%; however, efficiency of both indices declined substantially as BA control worsened. PMID:27004052

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

    PubMed Central

    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

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

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

    PubMed

    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

    2011-02-15

    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 the field, were scarce, leading to large uncertainties in the emission inventories. In this study, EFs of PAHs for nine commonly used crop residues burned in a typical Chinese rural cooking stove were measured in a 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. There was 80 6% of PAHs associated with PM2.5, and the mass percentage of PAHs in fine particles increased as the molecular weight increased. For freshly emitted PAHs, absorption into organic carbon, rather than adsorption, dominated the gas-particle partitioning. PMID:21247097

  18. In vivo quantification of fluorescent molecular markers in real-time by ratio imaging for diagnostic screening and image-guided surgery.

    PubMed

    Bogaards, A; Sterenborg, H J C M; Trachtenberg, J; Wilson, B C; Lilge, L

    2007-08-01

    Future applications of "molecular diagnostic screening" and "molecular image-guided surgery" will demand images of molecular markers with high resolution and high throughput (~ > or =30 frames/second). MRI, SPECT, PET, optical fluorescence tomography, hyper-spectral fluorescence imaging, and bioluminescence imaging do not offer such high frame rates. 2D optical fluorescence imaging can provide surface images with high resolution and high throughput. The ability to accurately quantify the fluorescence in vivo is critical to extract functional information of the disease state, however few methods are available. Here, a ratiometric 2D quantification method is introduced. Through mathematical modeling the performance was evaluated using optical properties that resembled biological tissues with the fluorescent marker Protoporhyrin IX. Experimentally the performance was evaluated in optical phantoms with different optical properties employing a novel prototype clinical imaging system. The clinical feasibility of real-time, image-guided surgery was demonstrated in patients undergoing prostatectomy. Discussed are the reasons why the introduced method leads to an increased quantification performance followed by modifications so it can be applied to novel fluorescent molecular markers as phthalocyanine 4 and dual-fluorescent markers. These offer additional advantages as these can provide a linear response to marker concentration and further minimize the dependence on autofluorescence and optical properties, as demonstrated through modeling. PMID:17868102

  19. Can mean platelet volume and mean platelet volume/platelet count ratio be used as a diagnostic marker for sepsis and systemic inflammatory response syndrome?

    PubMed Central

    Ates, Selma; Oksuz, Haf?ze; Dogu, B?rsen; Bozkus, Fulsen; Ucmak, Hasan; Yan?t, Fadime

    2015-01-01

    Objectives: To determine whether the mean platelet volume (MPV) and MPV/platelet (PLT) values can be used in the study of sepsis and systemic inflammatory response syndrome (SIRS). Methods: In this retrospective case-controlled study, 69 sepsis, 69 SIRS patients, and 72 control group who were treated in the years 2012-2013 were reviewed, and both the MPV and MPV/PLT rates were evaluated in all groups at Kahramanmaras Sutcu Imam University Intensive Care Unit, Kahramanmaras, Turkey. Results: Statistically significant difference was found between sepsis, SIRS, and control groups when comparing the MPV and MPV/PLT ratio (p<0.05), and no significant difference was found between sepsis and SIRS groups in terms of MPV and MPV/PLT ratio (p>0.05). Mean platelet volume values for sepsis and control groups was 10.07/8.731 femtoliter (fL) (p=0.000), and 9.45/8.731 fL (p=0.000) for SIRS and control groups. In the group of sepsis patients, the MPV was found to be at cut-off 8.915, sensitivity 71%, and specificity 63.9%. In the group of patients with SIRS, MPV was found to be at cut-off 8.85, sensitivity 69.6%, and specificity 62.5%. For the MPV/PLT values, the specificity and sensitivity were found to be insignificant. Conclusion: This study shows that although there was no significant reduction in the PLT values between the sepsis and SIRS patients, the MPV and MPV/PLT ratio values were found to have significant differences. However, the specificity and sensitivity of the values were not reliable standard to be used as a test. PMID:26446329

  20. Distribution, source, and ecological risk assessment of polycyclic aromatic hydrocarbons (PAHs) in surface sediments from the Hun River, northeast China.

    PubMed

    Liu, Zhiyang; He, Lixiong; Lu, Yingzhuan; Su, Jiao; Song, Han; Zeng, Xiangying; Yu, Zhiqiang

    2015-05-01

    In this study, the occurrence and distribution of 16 polycyclic aromatic hydrocarbons (PAHs), listed by the United States Environmental Protection Agency (US EPA), were investigated in surface sediment samples from the Hun River, northeast China. The data was then used to assess the potential ecological risk. The results indicated 15 PAHs were detected in these sediments, and the total concentrations of the 15 PAHs (not including naphthalene) ranged from 82.96 to 39,292.95ngg(-1) dry weight (dw), with an average value of 3705.54ngg(-1) dw, and 4-ring PAHs were the dominant compounds at most sites. The diagnostic parameters such as anthracene/(anthracene?+?phenanthrene), fluoranthene/(fluoranthene?+?pyrene), and indeno[1,2,3-cd]pyrene/(indeno[1,2,3-cd]pyrene?+?benzo[g,h,i]perylene) showed that they had been emitted from a number of different sources, especially the pyrolytic emissions. The results of the ecological risk assessment, which compared the PAH concentrations with the effect range low (ERL) and the effect range median (ERM) values, indicated that several individual PAH concentrations at four sites in the downstream section of the Hun River were higher than the ERM, suggesting that there was a potential ecological risk in these areas. PMID:25906922

  1. On the driving force of PAH production

    NASA Technical Reports Server (NTRS)

    Frenklach, Michael

    1989-01-01

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

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

    PubMed

    Nicolini, Jaqueline; Khan, Muhammad Y; Matsui, M; Ccco, Llian C; Yamamoto, Carlos I; Lopes, Wilson A; de Andrade, Jailson B; Pillon, Clenio N; Arizaga, Gregorio G Carbajal; Mangrich, Antonio S

    2015-01-01

    The aim of this work was to evaluate the concentrations of polycyclic aromatic hydrocarbons (PAHs) in soils to which solid shale materials (SSMs) were added as soil conditioners. The SSMs were derived from the Petrosix pyrolysis process developed by Petrobras (Brazil). An improved ultrasonic agitation method was used to extract the PAHs from the solid samples (soils amended with SSMs), and the concentrations of the compounds were determined by gas chromatography coupled to mass spectrometry (GC-MS). The procedure provided satisfactory recoveries, detection limits, and quantification limits. The two-, three-, and four-ring PAHs were most prevalent, and the highest concentration was obtained for phenanthrene (978??19 ?g kg(-1) in a pyrolyzed shale sample). The use of phenanthrene/anthracene and fluoranthene/pyrene ratios revealed that the PAHs were derived from petrogenic rather than pyrogenic sources. The measured PAH concentrations did not exceed national or international limit values, suggesting that the use of SSMs as soil conditioners should not cause environmental damage. PMID:25399121

  3. Polycyclic aromatic hydrocarbons (PAHs) and their derivatives (alkyl-PAHs, oxygenated-PAHs, nitrated-PAHs and azaarenes) in urban road dusts from Xi'an, Central China.

    PubMed

    Wei, Chong; Bandowe, Benjamin A Musa; Han, Yongming; Cao, Junji; Zhan, Changlin; Wilcke, Wolfgang

    2015-09-01

    Urban road dusts are carriers of polycyclic aromatic compounds (PACs) and are therefore considered to be a major source of contamination of other environmental compartments and a source of exposure to PACs for urban populations. We determined the occurrence, composition pattern and sources of several PACs (29 alkyl- and parent-PAHs, 15 oxygenated-PAHs (OPAHs), 4 azaarenes (AZAs), and 11 nitrated-PAHs (NPAHs)) in twenty urban road dusts and six suburban surface soils (0-5cm) from Xi'an, central China. The average concentrations of ?29PAHs, ?4AZAs, ?15OPAHs, and ?11NPAHs were 15767, 673, 4754, and 885 n gg(-1) in road dusts and 2067, 784, 854, and 118 ng g(-1) in surface soils, respectively. The concentrations of most individual PACs were higher in street dusts than suburban soils, particularly for PACs with molecular weight>192 g mol(-1). The enrichment factors of individual PACs were significantly positively correlated with log KOA and log KOW, indicating an increasing deposition and co-sorption of the PACs in urban dusts with decreasing volatility and increasing hydrophobicity. Significant correlations between the concentrations of individual and sum of PACs, carbon fractions (soot and char), and source-characteristic PACs (combustion-derived PAHs and retene, etc.), indicated that PAHs, OPAHs and AZAs were mostly directly emitted from combustion activities and had similar post-emission fates, but NPAHs were possibly more intensely photolyzed after deposition as well as being emitted from vehicle exhaust sources. The incremental lifetime cancer risk (ILCR) resulting from exposure to urban dust bound-PACs was higher than 10(-6), indicating a non-negligible cancer risk to residents of Xi'an. PMID:25543159

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

    PubMed

    Sauret, Caroline; Tedetti, Marc; Guigue, Catherine; Dumas, Chlo; Lami, Raphal; Pujo-Pay, Mireille; Conan, Pascal; Goutx, Madeleine; Ghiglione, Jean-Franois

    2016-03-01

    We evaluated the relative impact of anthropogenic polycyclic aromatic hydrocarbons (PAHs) among biogeochemical variables on total, metabolically active, and PAH bacterial communities in summer and winter in surface microlayer (SML) and subsurface seawaters (SSW) across short transects along the NW Mediterranean coast from three harbors, one wastewater effluent, and one nearshore observatory reference site. At both seasons, significant correlations were found between dissolved total PAH concentrations and PAH-degrading bacteria that formed a gradient from the shore to nearshore waters. Accumulation of PAH degraders was particularly high in the SML, where PAHs accumulated. Harbors and wastewater outfalls influenced drastically and in a different way the total and active bacterial community structure, but they only impacted the communities from the nearshore zone (<2km from the shore). By using direct multivariate statistical analysis, we confirmed the significant effect of PAH concentrations on the spatial and temporal dynamic of total and active communities in this area, but this effect was putted in perspective by the importance of other biogeochemical variables. PMID:26122564

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

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

    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.

  6. Comparison of fate profiles of PAHs in soil, sediments and mangrove leaves after oil spills by QSAR and QSPR.

    PubMed

    Tansel, Berrin; Lee, Mengshan; Tansel, Derya Z

    2013-08-15

    First order removal rates for 15 polyaromatic hydrocarbons (PAHs) in soil, sediments and mangrove leaves were compared in relation to the parameters used in fate transport analyses (i.e., octanol-water partition coefficient, organic carbon-water partition coefficient, solubility, diffusivity in water, HOMO-LUMO gap, molecular size, molecular aspect ratio). The quantitative structure activity relationships (QSAR) and quantitative structure property relationships (QSPR) showed that the rate of disappearance of PAHs is correlated with their diffusivities in water as well as molecular volumes in different media. Strong correlations for the rate of disappearance of PAHs in sediments could not be obtained in relation to most of the parameters evaluated. The analyses showed that the QSAR and QSPR correlations developed for removal rates of PAHs in soils would not be adequate for sediments and plant tissues. PMID:23756470

  7. Secondary effects of catalytic diesel particulate filters: conversion of PAHs versus formation of nitro-PAHs.

    PubMed

    Heeb, Norbert V; Schmid, Peter; Kohler, Martin; Gujer, Erika; Zennegg, Markus; Wenger, Daniela; Wichser, Adrian; Ulrich, Andrea; Gfeller, Urs; Honegger, Peter; Zeyer, Kerstin; Emmenegger, Lukas; Petermann, Jean-Luc; Czerwinski, Jan; Mosimann, Thomas; Kasper, Markus; Mayer, Andreas

    2008-05-15

    Diesel particulate filters (DPFs) are a promising technology to detoxify diesel exhaust. However, the secondary combustion of diesel soot and associated compounds may also induce the formation of new pollutants. Diesel soot is rated as carcinogenic to humans and also acts as a carrier for a variety of genotoxic compounds such as certain polycyclic aromatic hydrocarbons (PAHs) or nitrated PAHs (nitro-PAHs). Furthermore, diesel exhaust contains considerable amounts of nitric oxide (NO), which can be converted to more powerful nitrating species like nitrogen dioxide (NO2), nitric acid (HNO3), and others. This mix of compounds may support nitration reactions in DPFs. Herein we report effects of two cordierite-based, monolithic, wall-flow DPFs on emissions of genotoxic PAHs and nitro-PAHs and compare these findings with those of a reporter gene bioassay sensitive to aryl hydrocarbons (AHs). Soot combustion was either catalyzed with an iron- or a copper/iron-based fuel additive (fuel-borne catalysts). A heavy duty diesel engine, operated according to the 8-stage ISO 8178/4 C1 cycle, was used as test platform. Emissions of all investigated 4- to 6-ring PAHs were reduced by about 40-90%, including those rated as carcinogenic. Emissions of 1- and 2-nitronaphthalene increased by about 20-100%. Among the 3-ring nitro-PAHs, emissions of 3-nitrophenanthrene decreased by about 30%, whereas 9-nitrophenanthrene and 9-nitroanthracene were found only after DPFs. In case of 4-ring nitro-PAHs, emissions of 3-nitrofluoranthene, 1-nitropyrene, and 4-nitropyrene decreased by about 40-60% with DPFs. Total AH-receptor (AHR) agonist concentrations of diesel exhaust were lowered by 80-90%, when using the iron- and copper-based DPFs. The tested PAHs accounted for < 1% of the total AHR-mediated response, indicating that considerable amounts of other aryl hydrocarbons must be present in filtered and unfiltered exhaust. We conclude that both DPFs detoxified diesel exhaust with respect to total aryl hydrocarbons, including the investigated carcinogenic PAHs, but we also noticed a secondary formation of selected nitro-PAHs. Nitration reactions were found to be stereoselective with a preferential substitution of hydrogen atoms at peri-positions. The stereoisomers obtained are related to combustion chemistry, but differ from those formed upon atmospheric nitration of PAHs. PMID:18546721

  8. Effect of sorption and substrate pattern on PAH degradability

    SciTech Connect

    Ressler, B.P.; Kaempf, C.; Winter, J.

    1995-12-31

    The effect of sorption and the substrate pattern on the degradability of polycyclic aromatic hydrocarbons (PAHs) during bioremediation of PAH-contaminated silt in a slurry reactor was investigated. Biological degradation of high-molecular-weight PAH compounds sorbed to silt and clay particles was enhanced in the presence of low-molecular-weight PAHs. In soil suspensions containing silt contaminated with PAH compounds of different molecular weights, PAHs containing four aromatic rings were degraded more readily in the presence of naphthalene. Bioavailability of PAHs was correlated to the water solubility of different compounds; a significant limitation of bacterial growth and activity due to sorption of PAHs to the fine particles could not be observed.

  9. Effect of the gasoline additives on PAH emission.

    PubMed

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

    1998-04-01

    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

  10. ASSESSING RISKS FROM PHOTOACTIVATED TOXICITY OF PAHS TO AQUATIC ORGANISMS

    EPA Science Inventory

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

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

    PubMed Central

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

    2012-01-01

    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 (58.438.6, meanSD) after smoking. Receiver Operating Characteristic (ROC) analysis of PAHs among Polish and US subjects further showed that hydroxyfluorenes are most highly discriminative of smokers from nonsmokers followed by 2-naphthol and 1-hydroxypyrene. In conclusion, hydroxyfluorenes, particularly 1-hydroxyfluorene, and 2-naphthol are more selective of tobacco smoke than 1-hydroxypyrene and hydroxyphenanthrenes. Characterization of hydroxyfluorene and 2-naphthol metabolites in urine may improve the characterization of PAHs from tobacco smoke and related disease risks among smokers and nonsmokers. PMID:22428611

  12. Probabilistic ecological risk assessment of selected PAH`s in sediments near a petroleum refinery

    SciTech Connect

    Arnold, W.R.; Biddinger, G.R.

    1995-12-31

    Sediment samples were collected and analyzed for a number of polynuclear aromatic hydrocarbons (PAHs) along a gradient from a petroleum refinery`s wastewater diffuser. These data were used to calculate the potential risk to aquatic organisms using probabilistic modeling and Monte Carlo sampling procedures. Sediment chemistry data were used in conjunction with estimates of Biota-Sediment Accumulation Factors and Non-Polar Narcosis Theory to predict potential risk to bivalves. Bivalves were the receptors of choice because of their lack of a well-developed enzymatic system for metabolizing PAHs. Thus, they represent a species of higher inherent risk of adverse impact. PAHs considered in this paper span a broad range of octanol-water partition coefficients. Results indicate negligible risk of narcotic effects from PAHs existing near the refinery wastewater discharge.

  13. 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-...

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

    PubMed

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

    2010-05-01

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

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

    PubMed

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

    2010-05-01

    This study explores the impact of five different types of methyl esters on polycyclic aromatic hydrocarbon (PAH), nitrated-PAH and oxygenated PAH emissions. The measurements were conducted on a chassis dynamometer, according to the European regulation. Each of the five different biodiesels was blended with EN590 diesel at a proportion of 10-90% v/v (10% biodiesel concentration). The vehicle was a Euro 3 compliant common-rail diesel passenger car. Emission measurements were performed over the NEDC and compared with those of the real traffic-based Artemis driving cycles. The experimental results showed that the addition of biodiesel led to some important increases in low molecular-weight PAHs (phenanthrene and anthracene) and to both increases and reductions in large PAHs which are characterised by their carcinogenic and mutagenic properties. Nitro-PAHs were found to reduce with biodiesel whereas oxy-PAH emissions presented important increases with the biodiesel blends. The impact of biodiesel source material was particularly clear on the formation of PAH compounds. It was found that most PAH emissions decreased as the average load and speed of the driving cycle increased. Cold-start conditions negatively influenced the formation of most PAH compounds. A similar trend was observed with particulate alkane emissions. PMID:20083330

  16. Bioacessibility of PAHs in fuel soot assessed by an in vitro digestive model: effect of including an absorptive sink.

    PubMed

    Zhang, Yanyan; Pignatello, Joseph J; Tao, Shu; Xing, Baoshan

    2015-03-17

    Polycyclic aromatic hydrocarbons (PAHs) associated with soot or black carbon can enter the human digestive tract by unintentional ingestion of soil or other particles. This study investigated the bioaccessibility of 11 PAHs in a composite fuel soot sample using an in vitro digestive model that included silicone sheet as an absorptive sink during the small intestinal digestion stage. The sheet was meant to simulate the passive transfer of PAHs in lumen fluid across the small intestinal epithelium, which was postulated to promote desorption of labile PAHs from the soot by steepening the soot-fluid concentration gradient. We show that the presence of silicone sheet during a 4 h default digestion time significantly increased the apparent bioaccessible fraction (Bapp, %), defined as the sum in the sheet and digestive fluid relative to the total PAH determined. The ability to increase Bapp for most PAHs leveled off above a sheet-to-soot ratio of 2.0 g per 50 mg, indicating that the sheet is an effective absorptive sink and promotes desorption in the mentioned way. Enhancement of Bapp by the sheet correlated positively with the octanol-water partition coefficient (Kow), even though the partition coefficient of PAH between sheet and digestive fluid (which contains bile acid micelles) correlated negatively with Kow. It was hypothesized that PAHs initially in the soot exist in labile and nonlabile states. The fraction of labile PAH still sorbed to the soot residue after digestion, and the maximum possible (limiting) bioaccessibility (Blim) could be estimated by varying the sheet-to-soot ratio. We show conclusively that the increase in bioccessibility due to the presence of the sheet is accounted for by a corresponding decrease in fraction of labile PAH still sorbed to the soot. The Blim ranged from 30.8 to 62.4%, independent of molecular size. The nonlabile fraction of individual PAHs (69.2-37.6% in this case) is therefore large and needs to be taken into account in risk assessment. PMID:25692464

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

    PubMed

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

    2010-10-01

    A novel multivariate method based on principal component analysis of pre-processed sections of chromatograms is used to characterize the complex PAH pollution patterns in sediments from Guanabara Bay, Brazil. Five distinct sources of 3- to 6-ring PAHs could be revealed. The harbour is the most contaminated site in the bay, its plume stretches in a South West to North East direction and the chemical profile indicates mainly pyrogenic sources mixed with a fraction of high-molecular-weight petrogenic PAHs. Rio So Joo de Meriti is the second largest source of PAHs, and introduces mainly a fraction of low-molecular-weight petrogenic PAHs from the western region of Rio de Janeiro. The sites close to the ruptured pipeline at the Duque de Caxias Refinery show a distinctive pollution pattern indicating a heavy petroleum fraction. The method also led to the identification of new potential indicator ratios also involving coeluting peaks (e.g., triphenylene and chrysene). PMID:20709434

  18. PM, carbon, and PAH emissions from a diesel generator fuelled with soy-biodiesel blends.

    PubMed

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

    2010-07-15

    Biodiesels have received increasing attention as alternative fuels for diesel engines and generators. This study investigates the emissions of particulate matter (PM), total carbon (TC), e.g., organic/elemental carbons, and polycyclic aromatic hydrocarbons (PAHs) from a diesel generator fuelled with soy-biodiesel blends. Among the tested diesel blends (B0, B10 (10 vol% soy-biodiesel), B20, and B50), B20 exhibited the lowest PM emission concentration despite the loads (except the 5 kW case), whereas B10 displayed lower PM emission factors when operating at 0 and 10 kW than the other fuel blends. The emission concentrations or factors of EC, OC, and TC were the lowest when B10 or B20 was used regardless of the loading. Under all tested loads, the average concentrations of total-PAHs emitted from the generator using the B10 and B20 were lower (by 38% and 28%, respectively) than those using pure petroleum diesel fuel (B0), while the emission factors of total-PAHs decreased with an increasing ratio of biodiesel to premium diesel. With an increasing loading, although the brake specific fuel consumption decreased, the energy efficiency increased despite the bio/petroleum diesel ratio. Therefore, soy-biodiesel is promising for use as an alternative fuel for diesel generators to increase energy efficiency and reduce the PM, carbon, and PAH emissions. PMID:20307928

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

    PubMed

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

    2013-04-01

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

  20. Chemical and stable carbon isotopic characterization for PAHs in aerosol emitted from two indoor sources.

    PubMed

    Zhang, Liwen; Bai, Zhipeng; You, Yan; Wu, Jianhui; Feng, Yinchang; Zhu, Tan

    2009-04-01

    Polycyclic aromatic hydrocarbons (PAHs) are with great environmental concerns due to their toxic, mutagenic, and carcinogenic properties. The harmful effects caused by PAHs emitted from indoor sources may be more direct and serious. In this study, PAHs in aerosol from two typical indoor sources, the cooking fume (CF) and environmental tobacco smoke (ETS) were collected by simulation emission in a chamber. Eighteen PAHs were analyzed by GC/MS and GC/C/IRMS. The chemical profiles of these two sources were described. Results indicated that Fluoranthene, Pyrene and Fluorene in CF, and Fluorene, Phenanthrene, Indeno(1,2,3-cd)pyrene and Benz(a)anthracene in ETS, relative quantity of which were variable in a smaller range, can be regarded as tracers of indoor PAHs sources. There are distinct differences among the ratios of Benz(a)anthracene/Chrysene, Benzo(e)pyrene/Benzo(a)pyrene and Indeno(1,2,3-cd)pyrene/Benzo(g,h,i)perylene between CF and EST. Distribution of delta(13)C of individual PAHs in ETS samples ranged from -21.76 per thousand to -29.32 per thousand, wider than that in CF samples (-22.94 per thousand to -28.39 per thousand). The delta(13)C of Phenanthrene, Benz(a)anthracene, Benzo(b)fluoranthene, Benzo(k)fluoranthene and Indeno(1,2,3-cd)pyrene between these two sources showed great differences. The (13)C was enriched in low molecule weight compounds of CF samples and in high molecule weight compounds of ETS samples. PMID:19200570

  1. Are urinary PAHs biomarkers of controlled exposure to diesel exhaust?

    PubMed Central

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

    2016-01-01

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

  2. Distribution and Source of Polycyclic Aromatic Hydrocarbons (PAHs) in Water Dissolved Phase, Suspended Particulate Matter and Sediment from Weihe River in Northwest China

    PubMed Central

    Chen, Yuyun; Jia, Rui; Yang, Shengke

    2015-01-01

    Weihe River is a typical river located in the arid and semi-arid regions of Northwest China. In this study, the distribution and sources of 16 polycyclic aromatic hydrocarbons (PAHs) in Weihe River were investigated. The concentrations of ∑PAHs ranged from 351 to 4427 ng/L with a mean value of 835.4 ng/L in water dissolved phase (WDP), from 3557 ng/L to 147,907 ng/L with a mean value of 20,780 ng /L in suspended particulate matter (SPM), and from 362 to 15,667 ng/g dry weight (dw) with a mean value of 2000 ng/g dw in sediment, respectively. The concentrations of PAHs in Weihe River were higher compared with other rivers in the world. In both WDP and sediment, the highest concentrations of ∑PAHs were observed in the middle reach, while the lowest concentrations of ∑PAHs were found in the lower reach. For SPM, however, the PAHs concentrations in the lower reach were highest and the PAHs concentrations in the upper reach were lowest. The ratios of anthracene/(anthracene + phenanthrene) and fluoranthene/(fluoranthene + pyrene) reflected a pattern of both pyrolytic and petrogenic input of PAHs in Weihe River. The potential ecosystem risk assessment indicated that harmful biological impairments occur frequently in Weihe River. PMID:26561824

  3. Distribution and Source of Polycyclic Aromatic Hydrocarbons (PAHs) in Water Dissolved Phase, Suspended Particulate Matter and Sediment from Weihe River in Northwest China.

    PubMed

    Chen, Yuyun; Jia, Rui; Yang, Shengke

    2015-11-01

    Weihe River is a typical river located in the arid and semi-arid regions of Northwest China. In this study, the distribution and sources of 16 polycyclic aromatic hydrocarbons (PAHs) in Weihe River were investigated. The concentrations of ∑PAHs ranged from 351 to 4427 ng/L with a mean value of 835.4 ng/L in water dissolved phase (WDP), from 3557 ng/L to 147,907 ng/L with a mean value of 20,780 ng /L in suspended particulate matter (SPM), and from 362 to 15,667 ng/g dry weight (dw) with a mean value of 2000 ng/g dw in sediment, respectively. The concentrations of PAHs in Weihe River were higher compared with other rivers in the world. In both WDP and sediment, the highest concentrations of ∑PAHs were observed in the middle reach, while the lowest concentrations of ∑PAHs were found in the lower reach. For SPM, however, the PAHs concentrations in the lower reach were highest and the PAHs concentrations in the upper reach were lowest. The ratios of anthracene/(anthracene + phenanthrene) and fluoranthene/ (fluoranthene + pyrene) reflected a pattern of both pyrolytic and petrogenic input of PAHs in Weihe River. The potential ecosystem risk assessment indicated that harmful biological impairments occur frequently in Weihe River. PMID:26561824

  4. Seasonal and diurnal variations of atmospheric PAHs and OCPs in a suburban paddy field, South China: Impacts of meteorological parameters and sources

    NASA Astrophysics Data System (ADS)

    Wang, Yan; Li, Qilu; Wang, Shaorui; Wang, Yujie; Luo, Chunling; Li, Jun; Zhang, Gan

    2015-07-01

    The atmospheric contaminations of polycyclic aromatic hydrocarbons (PAHs), hexachlorocyclohexanes (HCHs), and DDTs have been extensively monitored for decades, but contaminations in agricultural paddy fields have rarely been reported. We measured the atmospheric PAH, HCH, and DDT constituents during different rice growth stages in a suburban paddy field in South China. Diurnal variations were found in the atmospheric concentrations of PAHs and HCHs, but not for DDTs. Additional nocturnal emissions and meteorological conditions, such as low nocturnal stable atmospheric boundary layers, may be mainly responsible for the higher PAH and HCH levels at night, respectively. Atmospheric concentrations of PAH, HCH, and DDT constituents varied with rice growth stage, but no regular seasonal variation was found, suggesting that rice growth has no significant influence on the atmospheric concentrations of these chemicals. A correlation analysis suggested that meteorological parameters, such as temperature, precipitation, mixing layer height, or wind speed, may directly or indirectly affect the air concentrations of PAHs, HCHs, and DDTs. Source apportionment showed that atmospheric PAHs, HCHs, and DDTs in the paddy field originated from mixed sources, and the contribution of each source varied with time. The isomer ratio of fluoranthene/(fluoranthene + pyrene) may result in an invalid diagnosis of PAHs.

  5. Diagnostic Development on NSTX

    SciTech Connect

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

    1999-12-16

    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.

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

    SciTech Connect

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

    2000-05-15

    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.

  7. Modified Fenton oxidation of polycyclic aromatic hydrocarbon (PAH)-contaminated soils and the potential of bioremediation as post-treatment.

    PubMed

    Venny; Gan, Suyin; Ng, Hoon Kiat

    2012-03-01

    This work focuses on the remediation of polycyclic aromatic hydrocarbon (PAH)-contaminated soil using modified Fenton (MF) treatment coupled with a novel chelating agent (CA), a more effective technique among currently available technologies. The performance of MF treatment to promote PAH oxidation in artificially contaminated soil was investigated in a packed column with a hydrogen peroxide (H(2)O(2)) delivery system simulating in-situ soil flushing which is more representative of field conditions. The effectiveness of process parameters H(2)O(2)/soil, Fe(3+)/soil, CA/soil weight ratios and reaction time were studied using a 2(4) three level factorial design experiments. An optimised operating condition of the MF treatment was observed at H(2)O(2)/soil 0.05, Fe(3+)/soil 0.025, CA/soil 0.04 and 3h reaction time with 79.42% and 68.08% PAH removals attainable for the upper and lower parts of the soil column respectively. The effects of natural attenuation and biostimulation process as post-treatment in the remediation of the PAH-contaminated soil were also studied. In all cases, 3-aromatic ring PAH (phenanthrene) was more readily degraded than 4-aromatic ring PAH (fluoranthene) regardless of the bioremediation approach. The results revealed that both natural attenuation and biostimulation could offer remarkable enhancement of up to 6.34% and 9.38% in PAH removals respectively after 8 weeks of incubation period. Overall, the results demonstrated that combined inorganic CA-enhanced MF treatment and bioremediation serves as a suitable strategy to enhance soil quality particularly to remediate soils heavily contaminated with mixtures of PAHs. PMID:22285087

  8. Gas-particle partitioning and precipitation scavenging of polycyclic aromatic hydrocarbons (PAHs) in the free troposphere in southern China

    NASA Astrophysics Data System (ADS)

    Li, Peng-hui; Wang, Yan; Li, Yu-hua; Wai, Ka-ming; Li, Hong-li; Tong, Lei

    2016-03-01

    Multi-phase (gaseous, particulate and rain) samples were collected simultaneously for the first time at a high-elevation mountain site in China during March to May 2009. The site, located in the free troposphere, is used to investigate the gas-particle partitioning, precipitation scavenging of polycyclic aromatic hydrocarbons (PAHs). The total measured concentrations of 15 USEPA PAHs varied from 2.67 to 137.00 ng/m3 (average of 24.10 ng/m3). Partitioning of PAHs between gaseous and particulate phases (log Kp) was well-correlated with the supercooled liquid vapor pressure in all samples (R2 = 0.730-0.985), but the slopes (-0.154 to -0.424) were significantly deviated from the expected value of -1. The observed Kp values were better predicted by the Dual model than the Koa model, pointing to the importance of soot carbon for PAH partitioning. The scavenging ratios varied among the individual PAH compound, ranged from 4.47 × 103 (BaA) to 1.02 × 105 (ACY). Particle scavenging was the dominant removal process, accounting over 75% of the total scavenging (except for BbF) for individual PAH compound. Relationships of Wp-particle fraction, Wp-supercooled vapor pressure were analyzed. The results suggested the particle scavenging by precipitation is less efficient for PAHs with higher molecular weights, while more volatile PAHs with lower molecular weights deposited on larger atmospheric particles were scavenged more efficiently. The efficiency of Wp was found to be increased with rain intensity. For gas scavenging, the dissolution and adsorption mechanisms shift their relative importance with different supercooled vapor pressure.

  9. PAHs, NITRO-PAHs, HOPANES, AND STERANES IN LAKE TROUT FROM LAKE MICHIGAN

    PubMed Central

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

    2015-01-01

    The present study examines concentrations and risks of polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs (NPAHs), steranes, and hopanes in lake trout collected in Lake Michigan. A total of 74 fish were collected in 2 seasons at 3 offshore sites. The total PAH concentration (Σ9PAH) in whole fish ranged from 223 pg/g to 1704 pg/g wet weight, and PAH concentrations and profiles were similar across season, site, and sex. The total NPAH (Σ9NPAH) concentrations ranged from 0.2 pg/g to 31 pg/g wet weight, and carcinogenic compounds, including 1-nitropyrene and 6-nitrochrysene, were detected. In the fall, NPAH concentrations were low at the Illinois site (0.2–0.5 pg/g wet wt), and site profiles differed considerably; in the spring, concentrations and profiles were similar across sites, possibly reflecting changes in fish behavior. In the fall, the total sterane (Σ5Sterane) and total hopane (Σ2Hopane) levels reached 808 pg/g and 141 pg/g wet weight, respectively, but concentrations in the spring were 10 times lower. Concentrations in eggs (fall only) were on the same order of magnitude as those in whole fish. These results demonstrate the presence of target semivolatile organic compounds in a top predator fish, and are consistent with PAH biodilution observed previously. Using the available toxicity information for PAHs and NPAHs, the expected cancer risk from consumption of lake trout sampled are low. However, NPAHs contributed a significant portion of the toxic equivalencies in some samples. The present study provides the first measurements of NPAHs in freshwater fish, and results suggest that additional assessment is warranted. PMID:24764175

  10. 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)

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

    2012-08-01

    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.

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

    PubMed

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

    2013-03-15

    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

  12. [PAH Cations as Viable Carriers of DIBs

    NASA Technical Reports Server (NTRS)

    Snow, Ted

    1998-01-01

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

  13. Heterogeneous oxidation and photochemistry of PAHs

    NASA Astrophysics Data System (ADS)

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

    2007-05-01

    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.

  14. Carbon in The Universe: PAHs and Clusters

    NASA Technical Reports Server (NTRS)

    Saykally, Richard J.

    1997-01-01

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

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

    SciTech Connect

    Vega, O.; Bressan, A.; Panuzzo, P.; Granato, G. L.; Silva, L.; Zeilinger, W. W.

    2010-10-01

    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.

  16. Investigation of polycyclic aromatic hydrocarbons (PAHs) and cyclic terpenoid biomarkers in the sediments of fishing harbors in Taiwan.

    PubMed

    Kao, Nien-Hsin; Su, Ming-Chien; Fan, Jheng-Rong; Yen, Chih-Chun

    2015-08-15

    Three fishing harbors were investigated to study the polycyclic aromatic hydrocarbons in the sediments and trace possible anthropogenic sources by identification of cyclic terpenoid biomarkers. Seventeen terpanes, 10 steranes and 10 bicyclic sesquiterpanes in the marine diesel and the three kinds of lubricants that are mainly used by fishing boats were identified and quantified. Eighteen biomarker diagnostic ratios are suggested and the correlation coefficients among the lubricants and sediment samples have the R(2) value greater than 0.73. Analyzed 16 PAHs in the sediment shows non-normal distributions and the Kruskal Wallis Test shows the significant differences (p value smaller than 0.05) with the greatest variability in benzo[g,h,i]perylene which more than 84% of the effective size (E.S.) is accounted. X-ray Photoelectron Spectroscopy (XPS) analysis was applied and the Kruskal Wallis Test shows a significant difference (p value smaller than 0.05) among certain atoms with the effective size greater than 60%. PMID:26049778

  17. A wintertime study of PAHs in fine and coarse aerosols in So Paulo city, Brazil

    NASA Astrophysics Data System (ADS)

    Bourotte, Christine; Forti, Maria-Cristina; Taniguchi, Satie; Bcego, Marcia Caruso; Lotufo, Paulo Andrade

    The Polycyclic aromatic hydrocarbons PAHs (naphthalene, acenaphthylene, acenaphthene, phenanthrene, fluoranthene, pyrene, benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, indeno(1,2,3-cd)pyrene and benzo(ghi)perylene) concentrations in fine (PM 2.5) and coarse (PM 2.5-10) atmospheric particulate matter were measured at So Paulo city, Brazil. The dominant PAH compounds were indeno(1,2,3-cd)pyrene, benzo(ghi)perylene and benzo(b)fluoranthene for both the fractions. The calculated ratios of some specific PAHs were in close agreement with those attributed to direct emissions of car exhaust. The factor analysis for PM 2.5 produced four factors: Factor 1 was attributed to diesel emissions, Factor 2 was attributed to stationary combustion source, Factor 3 was attributed to vehicular emissions and Factor 4 to natural gas combustion and biomass burning. For PM 2.5-10, Factor 1 was attributed to vehicular emissions and Factor 2 was attributed to a mixture of combustion sources such as natural gas combustion, incineration emissions and oil combustion. Also, vehicular emissions were assumed to be the major source of PAHs in the So Paulo city atmosphere.

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

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

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

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

    PubMed

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

    2015-03-17

    More stringent emission requirements for nonroad diesel engines introduced with U.S. Tier 4 Final and Euro Stage IV and V regulations have spurred the development of exhaust aftertreatment technologies. In this study, several aftertreatment configurations consisting of diesel oxidation catalysts (DOC), diesel particulate filters (DPF), Cu zeolite-, and vanadium-based selective catalytic reduction (SCR) catalysts, and ammonia oxidation (AMOX) catalysts are evaluated using both Nonroad Transient (NRTC) and Steady (8-mode NRSC) Cycles in order to understand both component and system-level effects of diesel aftertreatment on emissions of polycyclic aromatic hydrocarbons (PAH) and their nitrated derivatives (nitro-PAH). Emissions are reported for four configurations including engine-out, DOC+CuZ-SCR+AMOX, V-SCR+AMOX, and DOC+DPF+CuZ-SCR+AMOX. Mechanisms responsible for the reduction, and, in some cases, the formation of PAH and nitro-PAH compounds are discussed in detail, and suggestions are provided to minimize the formation of nitro-PAH compounds through aftertreatment design optimizations. Potency equivalency factors (PEFs) developed by the California Environmental Protection Agency are then applied to determine the impact of aftertreatment on PAH-derived exhaust toxicity. Finally, a comprehensive set of exhaust emissions including criteria pollutants, NO2, total hydrocarbons (THC), n-alkanes, branched alkanes, saturated cycloalkanes, aromatics, aldehydes, hopanes and steranes, and metals is provided, and the overall efficacy of the aftertreatment configurations is described. This detailed summary of emissions from a current nonroad diesel engine equipped with advanced aftertreatment can be used to more accurately model the impact of anthropogenic emissions on the atmosphere. PMID:25668360

  20. Recombination Rates of Electrons with Interstellar PAH Molecules

    NASA Technical Reports Server (NTRS)

    Ballester, Jorge (Cartographer)

    1996-01-01

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

  1. Implementation of a new atomic basis for the He I equilibrium line ratio technique for electron temperature and density diagnostic in the SOL for H-mode plasmas in DIII-D

    SciTech Connect

    Burgos, JMM; Schmitz, O.; Unterberg, Ezekial A; Loch, S. D.; Ballance, C. P.

    2011-01-01

    Evaluating the ratio of selected helium lines allows for measurement of electron densities and temperatures. This technique is applied for L-mode plasmas at TEXTOR (O. Schmitz et al., Plasma Phys. Control. Fusion 50 (2008) 115004). We report our first efforts to extend it to H-mode plasma diagnostics in DIII-D. This technique depends on the accuracy of the atomic data used in the collisional radiative model (CRM). We present predictions for the electron temperatures and densities by using recently calculated R-Matrix With Pseudostates (RMPS) and Convergent Close-Coupling (CCC) electron-impact excitation and ionization data. We include contributions from higher Rydberg states by means of the projection matrix. These effects become significant for high electron density conditions, which are typical in H-mode. We apply a non-equilibrium model for the time propagation of the ionization balance to predict line emission profiles from experimental H-mode data from DIII-D. (C) 2010 Elsevier B.V. All rights reserved.

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

    PubMed

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

    2016-04-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    Keywords: cellulose; biosorbent; PAHs; polycontaminated wastewaters; trace levels. Polycyclic aromatic hydrocarbons (PAHs), chemicals essentially formed during incomplete combustion of organic materials from anthropogenic activities, were present in all compartments of the ecosystem, air, water and soil. Notably, a part of PAHs found in aquatic system was introduced through industrial discharge waters. Since the Water Framework Directive has classified certain PAHs as priority hazardous substances, industrials are called to take account this kind of organic pollutants in their global environmental concern. Conventional materials such as activated carbons definitively proved their worth as finishing treatment systems but remained costly. In this study, we proposed to use cellulose grafted with glycidyl methacrylate [1] for the removal of PAHs present in discharge waters of surface treatment industries. Firstly, to develop the device, we worked with synthetic solutions containing 16 PAHs at 500 ng/L. Two types of grafted cellulose were tested over a closed-loop column with a concentration of 4g cellulose/L: cellulose C2 with a hydroxide group and cellulose C4 with an amine group. No PAH was retained by the raw cellulose whereas abatement percentages of PAHs were similar between C2 and C4 (94% and 98%, respectively, for the sum of the 16 PAHs) with an experiment duration of 400 min (corresponding to about 20 cycles through grafted cellulose). Secondly, to determine the shorter time to abate the amount maximum of PAHs through the system, a kinetic was realized from 20 min (one cycle) to 400 min with C4. The steady state (corresponding to about 95% of abatement of the total PAHs) was reached at 160 min. Finally, the system was then tested with real industrial discharge waters containing both mineral and organic compounds. The results indicated that the abatement percentage of PAHs was similar between C2 and C4, corroborating the tests with synthetic solution. In return, the grafted cellulose showed lower adsorption capacities of PAHs (about 40% for the total PAH content) when they were in real effluents than they were in synthetic solutions. However, it was observed that PAH composition in discharge waters was different than in synthetic solutions, qualitatively and quantitatively. Despite the presence of numerous other substances in industrial effluents at high concentrations (for instance metals equal to mg/L and salts to g/L), the grafted cellulose was demonstrated as suitable to remove organic substances at trace levels like PAHs (equal to ng/L). Reference: [1] Vismara E., Melone L., Gastaldi G., Cosentino C., Torri G. J. Hazardous Mat. 170 (2009) 798-808. Acknowledgements: The authors thank Agence de l'Eau, FEDER and the Conseil regional de Franche-Comté for financial support (NIRHOFEX Program).

  4. PCBs, PBDEs, and PAHs in Toronto air: spatial and seasonal trends and implications for contaminant transport.

    PubMed

    Melymuk, Lisa; Robson, Matthew; Helm, Paul A; Diamond, Miriam L

    2012-07-01

    The distributions of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and polycyclic aromatic hydrocarbons (PAHs) in the atmosphere of Toronto, Canada and the surrounding suburban/rural area were examined. A series of temporally- and spatially-distributed air samples was collected over a 1-year period with a high-volume active air sampler at one downtown site and polyurethane foam passive air samplers at 19 sites. Passive sampler air concentrations of ?PAHs ranged from 0.27 to 51 ng/m. Concentrations of ?PCBs ranged from 6.0 to 1300 pg/m, and concentrations of ?PBDEs ranged from 0.47 to 110 pg/m. All compounds exhibited the highest concentrations in the urban core, and lowest concentrations in the surrounding rural areas, however the exact ratio depended on location since concentrations varied considerably within the city. Results from the application of a radial dilution model highlighted the influence of the central business district (CBD) of the city as a source of contaminants to the surrounding environment, however the radial dilution comparison also demonstrated that sources outside the CBD have a significant influence on regional contaminant concentrations. A strong relationship between temperature and partial pressure of the gas-phase PCBs, low molecular weight PBDEs and less-reactive PAHs suggested that their dominant emissions originated from temperature-controlled processes such as volatilization from local sources of PCBs, PAHs and PBDEs at warm temperatures, condensation and deposition of emissions at cold temperatures, and ventilation of indoor air with elevated concentrations. The relationship between temperature and atmospheric PAH concentrations varied along the urban-rural gradient, which suggested that in highly urbanized areas, such as downtown Toronto, temperature-related processes have a significant impact on air concentrations, whereas winter emissions from domestic heating have a greater influence in areas with less impervious surface coverage. PMID:22578845

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

    NASA Astrophysics Data System (ADS)

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

    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.

  6. Predicting pore water EPA-34 PAH concentrations and toxicity in pyrogenic-impacted sediments using pyrene content.

    PubMed

    Arp, Hans Peter H; Azzolina, Nicholas A; Cornelissen, Gerard; Hawthorne, Steven B

    2011-06-15

    Sediment and freely dissolved pore water concentrations of the U.S. Environmental Protection Agency's list of 34 alkyl and parent PAHs (EPA-34) were measured in 335 sediment samples from 19 different sites impacted by manufactured gas plants, aluminum smelters and other pyrogenic sources. The total EPA-34 freely dissolved pore water concentration, C(pw,EPA-34), expressed as toxic units (TU) is currently considered one of the most accurate measures to assess risk at such sites; however, it is very seldom measured. With this data set, we address how accurately C(pw,EPA-34) can be estimated using limited 16 parent PAH data (EPA-16) commonly available for such sites. An exhaustive statistical analysis of the obtained data validated earlier observations that PAHs with more than 3 rings are present in similar relative abundances and their partitioning behavior typically follows Raoult's law and models developed for coal tar. As a result, sediment and freely dissolved pore water concentrations of pyrene and other 3- and 4-ring PAHs exhibit good log-log correlations (r² > 0.8) to most individual EPA-34 PAHs and also to C(pw,EPA-34). Correlations improve further by including the ratio of high to low molecular weight PAHs, as 2-ring PAHs exhibit the most variability in terms of their relative abundance. The most practical result of the current work is that log C(pw,EPA-34) estimated by the recommended pyrene-based estimation techniques was similarly well correlated to % survival of the benthic amphipods Hyalella azteca and Leptocheirus plumulosus as directly measured log C(pw,EPA-34) values (n = 211). Incorporation of the presented C(pw,EPA-34) estimation techniques could substantially improve risk assessments and guidelines for sediments impacted by pyrogenic residues, especially when limited data are available, without requiring any extra data or measurement costs. PMID:21595462

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

    PubMed

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

    2014-10-15

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

  8. Compound-specific radiocarbon analysis to evaluate the contribution of Peace River floodings to the PAH background in the Peace-Athabasca Delta

    NASA Astrophysics Data System (ADS)

    Jautzy, J. J.; Ahad, J. M.; Hall, R. I.; Wiklund, J. A.; Gobeil, C.; Savard, M. M.

    2013-12-01

    The oil sands of Northern Alberta, Canada are one of the largest hydrocarbon reserves in the world. The rapid growth of the bitumen exploitation in this region involves large scale mining infrastructure, raising questions about the environmental impact of these operations. One of the main issues is the emission of hazardous organic compounds such as polycyclic aromatic hydrocarbons (PAHs). PAHs, which are found naturally in petroleum, are also produced through incomplete combustion and diagenesis of organic matter. The complex nature of the surrounding geology (natural levels of bitumen) requires tools able to discriminate sources of pollutants. The establishment of the PAH background is crucial in order to investigate the impacts of oil sands mining in the Athabasca region. Here we present a new approach to discriminate the sources of alkylated PAHs (fossil or modern biomass) and their relative contributions. Using a dated sediment sequence from a lake situated in the Peace-Athabasca Delta periodically flooded by the Peace River, 6 different groups of parent and alkylated PAHs were extracted and collected by preparative capillary gas chromatography (PCGC) for natural abundance radiocarbon (14C) measurement. Three grouped layers each comprising approximately 10 years of sedimentation and spanning the period of mining operations (i.e., the past 40 years) were analyzed. We report here the first use of 14C measurements on alkylated PAHs extracted from lake sediments. Our results showed low radiocarbon content for all alkylated and parent PAHs analyzed in the three sediment layers. However, a slight trend toward a more modern PAH input can be seen up-core. PAH isomers ratios pointed to a major influence of petroleum input in the entire lake sequence, supporting the predominance of a fossil carbon source as indicated by the low radiocarbon contents. As the Peace River cuts through the Peace oil sands formation, our results can be explained by the main contribution of PAHs originating from periodic flooding events as previously documented for this lake. We further interpret the modern proportion of alkylated PAHs as being contributed from forest fires. These results provide greater insight into the variability of the alkylated PAH sources, and highlight the potential of this isotopic technique for source apportionment of airborne PAHs in lakes from the Athabasca oil sands region.

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

    PubMed

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

    2013-08-01

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

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

    PubMed Central

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

    2013-01-01

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

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

    PubMed

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

    2015-09-01

    Cloud water samples were collected from Mount Lushan, a high alpine area of southern China, and analyzed using GC-MS to investigate the concentration levels, seasonal variations, particle-dissolved phase partitioning, ecological risk of PAHs and its relationship to the atmosphere and rainwater. The average concentration of total (dissolved+particle) PAHs in cloud water was 819.90 ng/L, which ranged from 2.30 ng/L for DbA to 295.38 ng/L for PhA. PhA (33.11%) contributed the most individual PAHs, followed by Flu (28.24%). Distinct seasonal variations in the total PAHs measured in this research had a higher concentration during the spring and a lower concentration during the summer. When cloud events occurred, the concentration of the atmospheric PAHs of the two phases decreased. The contribution from the gaseous phase of total PAHs in the air to the dissolved phase in cloud water was up to 60.43%, but the particulate phase in the air only contributed 39.57% to the total scavenging. The contribution of total PAHs from the atmosphere to clouds is higher in the gaseous phase than in the particulate phase. A comparative study of the concentrations of cloud water and the closest rain water revealed that the PAH concentration in rainwater was 1.80 times less than that of cloud water and that the dominant individual compounds in cloud water and rainwater were PhA and Flu. A total of 81.27% of the PAHs in cloud samples and 72.21% of the PAHs in rain samples remained in the dissolved phase. Ecological risk assessment indicated that PAHs in cloud water in spring and summer caused a certain degree of ecosystem risk and the mean ecosystem risk in spring was higher than that in summer. PMID:25967478

  12. Assessment of polycyclic aromatic hydrocarbons (PAHs) contamination in surface soil of coal stockpile sites in South Kalimantan, Indonesia.

    PubMed

    Mizwar, Andy; Priatmadi, Bambang Joko; Abdi, Chairul; Trihadiningrum, Yulinah

    2016-03-01

    Concentrations, spatial distribution, and sources of 16 polycyclic aromatic hydrocarbons (PAHs), listed as priority pollutants by the United States Environmental Protection Agency (USEPA), were investigated in surface soils of three different coal stockpile, agricultural, and residential sites in South Kalimantan Province, Indonesia. Total PAHs concentration ranged from 4.69 to 22.67 mg kg(-1)-dw. PAHs concentrations in soil of coal stockpile sites were higher than those in agricultural and residential soil. A complex of petrogenic origin and pyrolytic sources was found within the study area, as suggested by the isomeric ratios of PAHs. The results of principal component analysis and multiple linear regressions (PCA/MLR) showed that three sources contributed to the PAHs in the study area, including biomass and coal combustion (48.46 %), raw coal (35.49 %), and vehicular emission (16.05 %). The high value of total benzo[a]pyrene equivalent concentration (B[a]Peq) suggests that local residents are exposed to a high carcinogenic potential. PMID:26861742

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

    NASA Astrophysics Data System (ADS)

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

    2013-06-01

    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.

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

    USGS Publications Warehouse

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

    1999-01-01

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

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

    EPA Science Inventory

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

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

    PubMed

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

    2014-06-01

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

  17. Theoretical spectroscopic study of protonated and deuteronated PAHs

    NASA Astrophysics Data System (ADS)

    Buragohain, Mridusmita; Pathak, Amit

    The study of Polycyclic Aromatic Hydrocarbon (PAH) plays a key role to understand astrophysical environments as they are ubiquitous in the Interstellar Medium (ISM). They account for about 5-10% of carbon budget in the universe and are responsible for the strong IR emission features at 3.3, 6.2, 7.7, 8.6, 11.2 and 12.7mum seen towards most of the interstellar objects including HII regions, reflection nebulae, planetary nebulae, late-type stars, as well as active star-forming regions. These IR features result from the relaxation of vibrationally excited PAHs. As PAHs are stable enough to survive the interstellar conditions, they could possibly be responsible for the enigmatic Diffuse Interstellar Bands (DIBs) which are optical absorption features on the interstellar extinction curve. The fact that interstellar PAHs are more likely to be ions has motivated the study of radical PAHs. Protonated PAHs formed by H(+) addition to neutral parent molecules, denoted as HPAH(+) , are an important form of closed shell PAH cation. Protonated forms show electronic transitions in the visible part of the spectrum where most DIBs are present, whereas neutral forms generally show their strongest electronic transitions in the UV region. We also report quantum chemical calculations on HPAH(+) and DPAH(+) (D(+) attached to PAH) to get the electronic and IR spectra to understand the IR emission and DIB features. A comparison of theoretical spectra with the available experimental spectra has also been carried out.

  18. Imaging of the PAH Emission Bands in the Orion Bar

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

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

    SciTech Connect

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

    2007-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

    Orecchio, Santino

    2011-04-01

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

  1. PAH Measurements in Air in the Athabasca Oil Sands Region.

    PubMed

    Hsu, Yu-Mei; Harner, Tom; Li, Henrik; Fellin, Phil

    2015-05-01

    Polycyclic aromatic hydrocarbon (PAH) measurements were conducted by Wood Buffalo Environmental Association (WBEA) at four community ambient Air quality Monitoring Stations (AMS) in the Athabasca Oil Sands Region (AOSR) in Northeastern Alberta, Canada. The 2012 and 2013 mean concentrations of a subset of the 22 PAH species were 9.5, 8.4, 8.8, and 32 ng m(-3) at AMS 1 (Fort McKay), AMS 6 (residential Fort McMurray), AMS 7 (downtown Fort McMurray), and AMS 14 (Anzac), respectively. The average PAH concentrations in Fort McKay and Fort McMurray were in the range of rural and semirural areas, but peak values reflect an industrial emission influence. At these stations, PAHs were generally associated with NO, NO2, PM2.5, and SO2, indicating the emissions were from the combustion sources such as industrial stacks, vehicles, residential heating, and forest fires, whereas the PAH concentrations at AMS 14 (∼35 km south of Fort McMurray) were more characteristic of urban areas with a unique pattern: eight of the lower molecular weight PAHs exhibited strong seasonality with higher levels during the warmer months. Enthalpies calculated from Clausius-Clapeyron plots for these eight PAHs suggest that atmospheric emissions were dominated by temperature-dependent processes such as volatilization at warm temperatures. These findings point to the potential importance of localized water-air and/or surface-air transfer on observed PAH concentrations in air. PMID:25844542

  2. The effects of PAH contamination on soil invertebrate communities

    SciTech Connect

    Snow-Ashbrook, J.L.; Erstfeld, K.M.

    1995-12-31

    Soils were collected from an abandoned industrial site to study the effects of historic polycyclic aromatic hydrocarbons (PAHs) on soil invertebrate communities. Nematode abundance and diversity, microarthropod abundance (orders Collembola and Acarina) and earthworm growth were evaluated. Physical and chemical characteristics of soils may affect both invertebrate community structure and the mobility/bioavailability of pollutants in soils. Soil characteristics were measured and included with PAH data in multiple regression analyses to identify factors which influences the responses observed in the soil invertebrate community. Positive associations were observed between eight invertebrate community endpoints and soil PAH content. For all of these endpoints but one, a higher degree of variability was explained when both PAH content and soil characteristics were considered. It is theorized that the positive response to soil PAH content may be the result of an increased abundance of PAH-degrading soil microbes. Increased microbial abundance could stimulate invertebrate communities by providing a direct food source or increasing the abundance of microbially-produced nutrients. These results suggest that both PAH content and soil characteristics significantly influenced the soil invertebrate community. It is not clear whether these factors influenced the invertebrate community independently, or whether differences in soil characteristics affected the community response by influencing the mobility or bioavailability of PAHs.

  3. Determination of PAHs in particulate air by micellar liquid chromatography

    SciTech Connect

    Kayali, M.N.; Rubio-Barroso, S.; Polo-Diez, L.M. . Dept. of Analytical Chemistry)

    1994-01-01

    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.

  4. Toxicological profile for polycyclic aromatic hydrocarbons (PAHs). update

    SciTech Connect

    1995-08-01

    This statement was prepared to give one information about polycyclic aromatic hydrocarbons (PAHs) and to emphasize the human health effects that may result from exposure to them. The Environmental Protection Agency (EPA) has identified 1,408 hazardous waste sites as the most serious in the nation. PAHs have been found in at least 600 of the sites on the NPL.

  5. Are Urinary PAHs Biomarkers of Controlled Exposure to Diesel Exhaust?

    EPA Science Inventory

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

  6. The differentiation of the character of solid lesions in the breast in the compression sonoelastography. Part II: Diagnostic value of BIRADS-US classification, Tsukuba score and FLR ratio

    PubMed Central

    2013-01-01

    Sonoelastography is a dynamically developing method of ultrasound examination used to differentiate the character of focal lesions in the breasts. The aim of the Part II of the study is to determine the usefulness of sonoelastography in the differentiation diagnosis of focal breast lesions including the evaluation of the diagnostic value of Tsukuba score and FLR ratio in characterizing solid lesions in the breasts. Furthermore, the paper provides a comparison of classic B-mode imaging and sonoelastography. Material and methods From January to July 2010 in the Ultrasound Department of the Cancer Centre, The Institute of Maria Sk?odowska-Curie, 375 breast ultrasound examinations were conducted. The examined group included patients who in B-mode examinations presented indications for pathological verification. They were 80 women aged between 17 and 83 (mean age was 50) with 99 solid focal lesions in the breasts. All patients underwent: the interview, physical examination, B-mode ultrasound examination and elastography of the mammary glands and axillary fossae. The visualized lesions were evaluated according to BIRADS-US classification and Tsukuba score as well as FLR ratio was calculated. In all cases, the histopathological and/or cytological verification of the tested lesions was obtained. Results In the group of 80 patients, the examination revealed 39 malignant neoplastic lesions and 60 benign ones. The mean age of women with malignant neoplasms was 55.07 (SD = 10.54), and with benign lesions 46.9 (SD = 15.47). In order to identify threshold values that distinguish benign lesions from malignant ones, a comparative analysis of statistical models based on BIRADS-US classification and Tsukuba score was conducted and the cut-off value for FLR was assumed. The sensitivity and specificity values for BIRADS-US 4/5 were 76.92% and 96.67% and for Tsukuba 3/4 64.1% and 98.33% respectively. The assumed FLR threshold value to differentiate between benign and malignant lesions in the breasts equaled 3.13. The combined application of both classifications (with the threshold value of BIRADS-US 4/Tsukuba 3) improved the total value of sensitivity and specificity of character differentiation of focal lesions (87.2% and 95% respectively). Conclusions In the case of problematic focal lesions, i.e. BIRADS-US 3, the study revealed that obtaining Tsukuba score of 1 and 2 for lesions classified as BIRADS-US 3 confirms their benign character. This allows to avoid the cytological verification. PMID:26673828

  7. Comparative Developmental Toxicity of Environmentally Relevant Oxygenated PAHs

    SciTech Connect

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

    2013-09-01

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

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

    SciTech Connect

    Joshi, M.M.; Lee, S.

    1995-12-31

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

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

    SciTech Connect

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

    1987-03-01

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

  10. Degradation of PAHs by ligninolytic enzymes of Irpex lacteus.

    PubMed

    Cajthaml, T; Erbanov, P; Kollmann, A; Novotn, C; Sasek, V; Mougin, C

    2008-01-01

    The ligninolytic fungus Irpex lacteus was shown as an efficient degrader of oligocyclic aromatic hydrocarbons (PAHs; 'polycyclic aromatic hydrocarbons') possessing 3-6 aromatic rings in complex liquid media. The strain produced mainly Mn-dependent peroxidase in media without pollutants. Activity of ligninolytic enzymes was higher in a N-limited medium. However, after contamination with PAHs (especially pyrene) the values increased and significant activity of Mn-independent peroxidase appeared in the complex medium. Other factors (such as the increase in nitrogen concentration or the presence of solvent(s) for dissolution of PAHs) had no effect. Cytochrome P-450 was detected in the microsomal fraction of biomass grown in the complex medium. The rate of PAH degradation was also affected by the presence of various combinations of PAHs. However, independently of the enzyme activities, anthracene was shown to have a positive influence on degradation of pyrene and fluoranthene. PMID:18759111

  11. Laboratory Photo-chemistry of PAHs: Ionization versus Fragmentation

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

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

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

    SciTech Connect

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

    2015-01-01

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

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

    PubMed Central

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

    2011-01-01

    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. PMID:19661084

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

    PubMed

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

    2015-01-01

    Passive sampling devices were used to measure air vapor and water dissolved phase concentrations of 33 polycyclic aromatic hydrocarbons (PAHs) and 22 oxygenated PAHs (OPAHs) at four Gulf of Mexico coastal sites prior to, during, and after shoreline oiling from the Deepwater Horizon oil spill (DWH). Measurements were taken at each site over a 13 month period, and flux across the water-air boundary was determined. This is the first report of vapor phase and flux of both PAHs and OPAHs during the DWH. Vapor phase sum PAH and OPAH concentrations ranged between 1 and 24 ng/m(3) and 0.3 and 27 ng/m(3), respectively. PAH and OPAH concentrations in air exhibited different spatial and temporal trends than in water, and air-water flux of 13 individual PAHs were strongly associated with the DWH incident. The largest PAH volatilizations occurred at the sites in Alabama and Mississippi in the summer, each nominally 10,000 ng/m(2)/day. Acenaphthene was the PAH with the highest observed volatilization rate of 6800 ng/m(2)/day in September 2010. This work represents additional evidence of the DWH incident contributing to air contamination, and provides one of the first quantitative air-water chemical flux determinations with passive sampling technology. PMID:25412353

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

    PubMed Central

    2015-01-01

    Passive sampling devices were used to measure air vapor and water dissolved phase concentrations of 33 polycyclic aromatic hydrocarbons (PAHs) and 22 oxygenated PAHs (OPAHs) at four Gulf of Mexico coastal sites prior to, during, and after shoreline oiling from the Deepwater Horizon oil spill (DWH). Measurements were taken at each site over a 13 month period, and flux across the water–air boundary was determined. This is the first report of vapor phase and flux of both PAHs and OPAHs during the DWH. Vapor phase sum PAH and OPAH concentrations ranged between 1 and 24 ng/m3 and 0.3 and 27 ng/m3, respectively. PAH and OPAH concentrations in air exhibited different spatial and temporal trends than in water, and air–water flux of 13 individual PAHs were strongly associated with the DWH incident. The largest PAH volatilizations occurred at the sites in Alabama and Mississippi in the summer, each nominally 10 000 ng/m2/day. Acenaphthene was the PAH with the highest observed volatilization rate of 6800 ng/m2/day in September 2010. This work represents additional evidence of the DWH incident contributing to air contamination, and provides one of the first quantitative air–water chemical flux determinations with passive sampling technology. PMID:25412353

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

    NASA Astrophysics Data System (ADS)

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

    2010-05-01

    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.

  17. Comparison of a bioremediation process of PAHs in a PAH-contaminated soil at field and laboratory scales.

    PubMed

    Lors, Christine; Damidot, Denis; Ponge, Jean-Franois; Pri, Frdric

    2012-06-01

    A laboratory experiment was carried on the same initial soil and at the same time than a windrow treatment in order to compare results at field and laboratory scales for a soil mainly contaminated with PAHs. After 6 months, laboratory experiments gave similar but less scattered results than those obtained in the field indicating that the field biotreatment was well optimised. The total amount of PAHs degraded after 6 months was ca. 90% and degradation rates followed a negative exponential trend. Relative degradation rates of 3- and 4-ring PAHs were about 32 and 7.2 times greater than those of 5- and 6-ring PAHs, respectively. With respect to the bacterial community, bacteria belonging to Gamma-proteobacteria persisted whereas Beta-proteobacteria appeared after three months of biotreatment when PAH concentration was low enough to render the soil non-ecotoxic. PMID:22390976

  18. Integrated diagnostics

    NASA Technical Reports Server (NTRS)

    Hunthausen, Roger J.

    1988-01-01

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

  19. Heating and Cooling in the Translucent ISM: PAHs and [C II] in High Galactic Latitude Clouds

    NASA Astrophysics Data System (ADS)

    Ingalls, James; Bania, Thomas

    2007-05-01

    The systematic study of the emission from unidentified infrared bands (UIBs) and [C II] in translucent clouds can provide the missing key empirical information needed to understand the energetics of translucent gas in the Milky Way. Current consensus ascribes the UIB emission features at 3.3, 6.2, 7.7, 8.6, 11.3, and 12.7 microns to fluorescent emission from PAH molecules excited by local FUV photons. Thus observation of the UIBs in high Galactic latitude molecular clouds (HLCs) coupled with existing measurements of [C II] and FIR emission, allow us to make a direct assessment of the relative importance of heating by both large and small (PAH) grains. In our GO-2 Spitzer program 20093, we detected the faintest PAH emission spectra in Galactic clouds to date, demonstrating the unique capabilities of the Spitzer IRS to spectrally image low-extinction regions. The derived PAH band strength in our HLC sample is linearly correlated with [C II ] integrated intensity. The 7.7/11.3 micron intensity ratio, which is related to the PAH ionization fraction, appears to be inversely proportional to [C II]. Unfortunately the large scatter and paucity of data points in key regions of [C II]-space makes this potentially groundbreaking result difficult to establish reliably. The proposed IRS Short-Low observations will triple the sample size of HLC positions with both UIB and [C II] measurements from 11 to 33 lines of sight, with only a 1.4-fold increase in observatory time over our GO-2 program. It will fill the gaps in [C II] coverage in our UIB sample and greatly enhance the statistical significance of our results. Our ultimate goal is to clarify the relationship between PAH ionization fraction, which crucially affects gas heating, and [C II] intensity, which measures gas cooling. This research can dramatically improve our understanding of the most important processes that govern the thermal properties of ISM gas in low-extinction environments.

  20. Infrared absorption and emission characteristics of interstellar PAHs

    NASA Technical Reports Server (NTRS)

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

    1986-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

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

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

    PubMed Central

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

    2012-01-01

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

  3. Metabolites of polycyclic aromatic hydrocarbons (PAHs) in bile as biomarkers of pollution in European eel (Anguilla anguilla) from German rivers.

    PubMed

    Nagel, F; Kammann, U; Wagner, C; Hanel, R

    2012-02-01

    In the light of the alarming decline of the European eel (Anguilla anguilla L.) population, there is an urgent need to define ecological indicators for eel habitat quality. Due to an increasing shortage of glass eels available for local stock enhancement, the decision of whether restocking is a valuable management tool to increase high-quality silver eel escapement to the sea needs to be evaluated. Organic contaminants, such as polycyclic aromatic hydrocarbons (PAHs), are among the major threats to fish in their habitat. Therefore, the aim of the investigation presented here was to examine metabolites of PAHs in eel bile as one possible marker for habitat quality. In total, 170 yellow eels were collected in the rivers Rhine, Ems, Weser, Elbe, Havel, Schlei, Eider, Trave, Warnow, Peene, Uecker, and Oder in 2009. PAH metabolites in eel bile were analyzed using high-performance liquid chromatography with fluorescence detection. Metabolites of pyrene and phenanthrene were investigated. Concentrations of PAH metabolites in eel bile varied significantly between several rivers, with the highest mean concentrations of 1-hydroxypyrene and 1-hydroxyphenanthrene in eel bile from the river Trave (2421 and 632 ng/ml). Moreover, huge differences in the ratio of 1-hydroxypyrene to 1-hydroxyphenanthrene, with the highest mean value in eel bile from the river Ems (7.43) and the lowest mean value in eel bile from the river Uecker (0.70), indicate different sources of PAH contamination. A comparative analysis of PAH-metabolite contamination of eels in different river systems is seen as a first step toward a classification of freshwater habitats for restocking purposes. PMID:21706228

  4. Measuring picogram per liter concentrations of freely dissolved parent and alkyl PAHs (PAH-34), using passive sampling with polyoxymethylene.

    PubMed

    Hawthorne, Steven B; Jonker, Michiel T O; van der Heijden, Stephan A; Grabanski, Carol B; Azzolina, Nicholas A; Miller, David J

    2011-09-01

    Passive sampling with nondepletive sorbents is receiving increasing interest because of its potential to measure freely dissolved concentrations of hydrophobic organic compounds (HOCs) at very low concentrations, as well as its potential for both laboratory use and field deployment. However, consistent approaches have yet to be developed for the majority of HOCs of environmental and regulatory interest. In the present study, a passive sampling method was developed which allows the freely dissolved concentrations of 18 parent and 16 groups of alkyl polycyclic aromatic hydrocarbons (PAHs) on the U.S. Environmental Protection Agency (USEPA)'s "PAH-34" target compound list to be measured. Commercially available 76-?m-thick polyoxymethylene (POM) was placed in sediment/water slurries and exposed for up to 126 days, with 28 days found to be sufficient to obtain equilibrium among the sediment, water, and POM phases for the target 2- to 6-ring PAHs. The POM/water partition coefficients (K(POM)) necessary to calculate freely dissolved concentrations for parent PAHs were determined in two separate laboratories (one using pure standards, and the other using coal tar/petroleum-contaminated sediments) and agreed very well. Since the so-called "16" alkyl PAHs on the PAH-34 list actually include several hundreds of isomers for which no standards exist, sediments impacted by coal tar, or spiked with a coal tar/petroleum nonaqueous phase liquid (NAPL) were also used to measure K(POM) values for each alkyl PAH cluster. The log K(POM) values ranged from ca. 3.0 to 6.2 for 2- to 6-ring parent PAHs, and correlated well with SPARC octanol/water coefficients (K(OW)) (correlation coefficient of r(2) = 0.986). However, log K(POM) values for alkyl PAHs deviated increasingly from SPARC log K(OW) values with increasing degree of alkylation. A simple empirical model that incorporates the number of carbon atoms in a PAH gave a better fit to the experimental log K(POM) values, and was used to estimate log K(POM) for alkyl PAHs that could not be directly measured. Detection limits (as freely dissolved concentrations) ranged from ca. 1 part per trillion (ng/L) for the 2-ring PAH naphthalene, down to <1 pg/L (part per quadrillion) for the 5- and 6-ring PAHs. Sorption isotherms were linear (r(2) > 0.99) over at least 4 orders of magnitude. PMID:21755996

  5. Photoinduced degradation of PAHs in the presence of ozone

    SciTech Connect

    Schutt, W.S.; Li, Y.; Sigman, M.E. |

    1995-12-31

    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.

  6. Gaseous and adsorbed PAH in an iron foundry.

    PubMed Central

    Knecht, U; Elliehausen, H J; Woitowitz, H J

    1986-01-01

    The increased risk of lung cancer among foundry workers is assumed to be associated with the inhalation of gaseous and particle bound polycyclic aromatic hydrocarbons (PAH). These compounds are produced during pyrolysis of carbon containing loading material in the moulding sand. The concentrations of 20 PAH, some of which are carcinogenic, have been determined in the dusty casting area of an iron foundry by means of gas chromatography and mass spectrometry. The total dust was fractionated by means of a precision cascade impactor. It was possible to differentiate the PAH load in microgram/mg dust in seven particle size fractions ranging from 0.36- greater than or equal to 24.95 microns. Initially, there was an increase of the adsorbed PAH mass concentration with increasing particle diameter up to a maximum of 1.1 microgram/mg in the dust of the 1.57 micron fraction. Thereafter there was a continuous decrease of PAH mass concentration with increasing particle size. When the differing weights of the seven fractions are taken into account, however, the total PAH load of the individual fractions increases steadily with increasing particle size. The inhalable fine dust, 31.4% of the total dust, contains 49.9% of the total adsorbed PAH. The gas phase contained on average three times more carcinogenic PAH with four and five rings than was adsorbed on the dust. Thus the percentage of the gaseous substances amounts to 77% of the total PAH load at the place of work in an iron foundry. PMID:3801335

  7. A Herschel SPIRE Study of M81: Separating Cold and Warm PAH Emissions

    NASA Astrophysics Data System (ADS)

    Lu, Nanyao Y.; Bendo, G.; VNGS Team

    2011-05-01

    We study correlations among three distinct dust emission components in the interstellar medium of the galaxy M81 at a sub-kpc resolution: (a) I_8, the surface brightness of non-stellar emission in Spitzer IRAC 8 um band, dominated by the so-called PAH emission features, (b) I_24, that of hot continuum emission in Spitzer MIPS 24 um band, arising from small dust grains powered mainly by young stars, and (c) I_500, that of cold dust continuum emission in Herschel SPIRE 500 um band, from large dust grains heated by evolved stars. Both I_8/I_500 and I_24/I_500 ratios increase towards active star-forming regions, consistent with the view that both (a) and (b) are correlated with current star formation. But as I_24/I_500 decreases to zero, I_8/I_500 approaches to a finite, positive value of 0.05 or greater. This implies that 57% of the 8 um non-stellar emission is "cold," arising from regions, where the 24 um emission is relatively insignificant. Since it is likely that the fraction of this cold component in the PAH emission varies from galaxy to galaxy, making the PAH luminosity a rather poor star formation tracer in general.

  8. Compound amino acids added in media improved Solanum nigrum L. phytoremediating CD-PAHS contaminated soil.

    PubMed

    Wei, Shuhe; Bai, Jiayi; Yang, Chuanjie; Zhang, Qianru; Knorrm, Klaus-Holger; Zhan, Jie; Gao, Qianhui

    2016-04-01

    Cd hyperaccumulator Solanum nigrum L. was a promising plant used to simultaneously remediate Cd-PAHs combined pollution soil through its extra accumulation capacity and rhizosphere degradation. This article compared the strengthening remediation role of cysteine (Cys), glycine (Gly) and glutamic acid (Glu) with EDTA and TW80. The results showed that the addition of 0.03 mmol L(-1) Cys, Gly, and Glu didn't significantly impact (p < 0.05) shoot biomass of S. nigrum, but obviously increased Cd concentration. Therefore, Cd capacity (µg pot(-1)) in shoots of S. nigrum was significantly increased (p < 0.05) by 37.7% compared to the control without reagent added. At the meantime, the PAHs degradation ratio in rhizoshpere was increased by 34.5%. Basically, the improving role of Cys, Gly, and Glu was higher than EDTA and TW80. The main reasons of enhanced the accumulation of S. nigrum to Cd might lie in the addition of Cys, Gly, and Glu which reduced pH and increased extractable Cd concentration in rhizosphere and phytochelatines (PCs) concentration in leaves. As for the degradation of PAHs in rhizosphere, increased microorganism number might be play important role. PMID:26515779

  9. 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 Central

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

    2007-01-01

    Bioaugmentation of soil polluted with polycyclic aromatic hydrocarbons (PAHs) is often disappointing because of the low survival rate and low activity of the introduced degrader bacteria. We therefore investigated the possibility of priming PAH degradation in soil by adding 2% of bioremediated soil with a high capacity for PAH degradation. The culturable PAH-degrading community of the bioremediated primer soil was dominated by Mycobacterium spp. A microcosm containing pristine soil artificially polluted with PAHs and primed with bioremediated soil showed a fast, 100- to 1,000-fold increase in numbers of culturable phenanthrene-, pyrene-, and fluoranthene degraders and a 160-fold increase in copy numbers of the mycobacterial PAH dioxygenase gene pdo1. A nonpolluted microcosm primed with bioremediated soil showed a high rate of survival of the introduced degrader community during the 112 days of incubation. 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

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

    NASA Astrophysics Data System (ADS)

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

    2016-01-01

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

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

    PubMed

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

    2016-01-01

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

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

    SciTech Connect

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

    1985-02-01

    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.

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

    PubMed

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

    2016-06-01

    A total of 46 polycyclic aromatic hydrocarbons (PAHs, 21 parent and 25 alkylated) were determined in seawater, surface sediment and oyster from coastal area of Dalian, North China. The concentration of Σ46PAHs in seawater, sediment, and oyster were 136-621ng/L, 172-4700ng/g dry weight (dw) and 60.0-129 ng/g wet weight (ww) in winter, and 65.0-1130ng/L, 71.1-1090ng/g dw and 72.8-216ng/g ww in summer, respectively. High PAH levels were found in industrial area both in winter and summer. Selected PAH levels in sediments were compared with Sediments Quality Guidelines (ERM-ERL, TEL-PEL indexes) for evaluation probable toxic effects on marine organism and the results indicate that surface sediment from all sampling sites have a low to medium ecotoxicological risk. Daily intake of PAHs via oyster as seafood by humans were estimated and the results indicated that oyster intake would not pose a health risk to humans even 30 days after a oil spill accident near by. Water-sediment exchange analysis showed that, both in winter and summer, the fluxes for most high molecular weight PAHs were from seawater to sediment, while for low molecular weight PAHs, an equilibrium was reached between seawater and sediment. PMID:26874984

  14. Behavior of PAH/mineral associations during thermodesorption: impact for the determination of mineral retention properties towards PAHs.

    PubMed

    Biache, Coralie; Lorgeoux, Catherine; Saada, Alain; Faure, Pierre

    2015-05-01

    Polycyclic aromatic hydrocarbons (PAHs) associated with two minerals (silica sand and bentonite) presenting opposite retention properties were analyzed with a thermodesorption (Td)-GC-MS coupling in order to validate this technique as a new and rapid way to evaluate the solid sorption properties. Two analysis modes were used, evolved gas analysis (EGA) and Td with cryo-trap. EGA allowed a real-time monitoring of the compounds desorbed during a temperature program and gave a first screening of the samples while Td gave more precise indications on compound abundances for selected temperature ranges. When associated with silica sand, PAHs were released at relatively low temperatures (<300C) close to corresponding boiling point, whereas for the PAH/bentonite mixture, PAHs were desorbed at much higher temperatures; they were also present in much lower abundance and were associated with mono-aromatic compounds. With bentonite, the PAH abundances decreased and the mono-aromatics increased with the increasing PAH molecular weight. These results indicated a clear PAH retention by the bentonite due to polymerization, followed by a thermal cracking at higher temperatures. The Td-GC-MS was proven to efficiently underline differences in retention properties of two minerals, and this study highlights the great potential of this technique to evaluate compound/matrix bond strength and interaction. PMID:25772555

  15. Distribution, sources, and potential risk of polycyclic aromatic hydrocarbons (PAHs) in drinking water resources from Henan Province in middle of China.

    PubMed

    Ma, Ying-ge; Cheng, Jin-ping; Jiao, Fei; Duo, Ke-xin; Rong, Zheng; Li, Ming; Wang, Wen-hua

    2008-11-01

    Distribution and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in drinking water resources have been carried out for the first time in Henan Province, China. Water samples collected from four river systems and their tributaries, as well as groundwater resources, were analyzed according to EPA method 525.2. Total of 68 water samples were collected in 18 cities in Henan province in May, August and November, 2001. Concentrations of sum of 16 priority PAHs in water samples ranged from 15 to 844 ng/L with a mean value of 178 +/- 210 ng/L (n = 68). The spatial and temporal distribution of PAHs showed that the Huanghe and the Huaihe river systems had relatively higher concentrations of total PAHs. Higher concentrations of total PAHs were observed in August and November than in May, with respective mean values of 262, 232 and 33.6 ng/L. Ratios of Ant/(Ant + Phe) and Flur/(Flur + Pyr) were calculated to evaluate the possible sources of PAH contamination, which indicated that the coal combustion sources were the main contributors to PAHs in most drinking water resources. Some petrogenic (or pyrolytic) sources of PAHs were also found. The toxic equivalency factors (TEFs) were used to calculate benzo[a]pyrene equivalents (BaPE) for water samples. The average value of BaPE was 0.6 ng/L. The values in most stations were much lower than the guideline values in drinking water of Chinese Environmental Protection Agency (CEPA, 2.8 ng/L) and the US Environmental Protection Agency (US EPA, 200 ng/L). Overall, the drinking water resources in Henan province showed some carcinogenic potential. PMID:18074237

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

    PubMed

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

    2008-06-01

    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

  17. Deuterium Enrichment of PAHs by VUV Irradiation of Interstellar Ices

    NASA Technical Reports Server (NTRS)

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

    1998-01-01

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

  18. Assessing PAH exposure in feral finfish from the Northwest Atlantic.

    PubMed

    Hellou, J; Leonard, J; Collier, T K; Ariese, F

    2006-04-01

    Polycyclic aromatic hydrocarbon (PAH) concentrations were examined in small finfish (<30 cm) represented by capelin, sand lance, American plaice, yellowtail flounder and herring collected opportunistically in various NAFO divisions. Analyses were performed on whole fish and in a portion of the samples; concentrations in internal organs were compared to the rest of the carcass. The effect of pool size, size differences within and between species, lipid content and location were examined to interpret PAH concentrations. Measurements were carried out before the development of the Hibernia oil fields and represent baseline levels for future comparison. Limits in assessing future risk that could be due to discharges of produced water or accidental oil spills are also discussed. Increasing knowledge on the bioaccumulation of PAH, on the production of bile metabolites, the formation of DNA-adducts and of the potential toxic effects associated with PAH will lead to better ecosystem management and protection for future generations. PMID:16364371

  19. Bioremediation of coal tar PAH in soils using biodiesel.

    PubMed

    Taylor, L T; Jones, D M

    2001-08-01

    The addition of biodiesel together with nitrate and phosphate to soil containing coal tar, in laboratory and field experiments, resulted in degradation of coal tar polycyclic aromatic hydrocarbons (PAH) that was not apparent when the nutrients alone were added. The addition of motor diesel fuel instead of biodiesel was also tested. Over the 55 days of the field and laboratory experiments, the biodiesel resulted in an increased degradation of naphthalene in the coal tar by 52% and 85%, respectively, and motor diesel resulted in increased depletions of 85% and 96%, respectively. Other PAH containing up to four rings were depleted to lesser extents. The increases in PAH biodegradation by the diesel treatments were ascribed to tar solubilisation and dispersion thereby increasing the PAH bioavailability. The ready biodegradability and low phytotoxicity of biodiesel suggest that it may be suitable as a novel treatment for the bioremediation of coal tar contaminated soils. PMID:11513400

  20. Effects of PAHs on the feeding activity of tubificid worms

    SciTech Connect

    Lotufo, G.R.

    1994-12-31

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

  1. 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...

  2. Polycyclic Aromatic Hydrocarbons and Astrophysics: The State of the Pah Model and a Possible Tracer of Nitrogen in Carbon-Rich Dust

    NASA Technical Reports Server (NTRS)

    Hudgins, Douglas M.; Allamandola, Louis J.

    2003-01-01

    Over the past fifteen years, thanks to significant, parallel advancements in observational, experimental, and theoretical techniques, tremendous strides have been made in our understanding of the role aromatic materials play in the interstellar medium (ISM). Twenty years ago, the possible existence of an abundant population of large, carbon-rich molecules in the ISM was unthinkable. Today, the unmistakable spectroscopic signatures of polycyclic aromatic hydrocarbon molecules (PAHs) - shockingly large molecules by the standards of traditional interstellar chemistry - are recognized throughout the Universe. In this paper, we will examine the current state of the interstellar PAH model and its utility as a diagnostic tool to derive insight into the nature of the interstellar PAH population. As an example of this application, we will examine the results of our recent spectroscopic studies of polycyclic aromatic nitrogen heterocycles (PANHs)-PAHs with an atom of nitrogen substituted into the aromatic skeleton-and discuss a possible tracer of such species amongst the interstellar PAH emission bands in the latest observational data.

  3. 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

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

    1982-01-01

    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.

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

    PubMed Central

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

    2012-01-01

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

  5. Bioremediation of PAH contaminated soil samples

    SciTech Connect

    Joshi, M.M.; Lee, S.

    1994-12-31

    Soils contaminated with polynuclear aromatic hydrocarbons (PAHs) pose a hazard to life. The remediation of such sites can be done using physical, chemical, and biological treatment methods or a combination of them. It is of interest to study the decontamination of soil using bioremediation. The experiments were conducted using Acinetobacter (ATCC 31012) at room temperature without pH or temperature control. In the first series of experiments, contaminated soil samples obtained from Alberta Research Council were analyzed to determine the toxic contaminant and their composition in the soil. These samples were then treated using aerobic fermentation and removal efficiency for each contaminant was determined. In the second series of experiments, a single contaminant was used to prepare a synthetic soil sample. This sample of known composition was then treated using aerobic fermentation in continuously stirred flasks. In one set of flasks, contaminant was the only carbon source and in the other set, starch was an additional carbon source. In the third series of experiments, the synthetic contaminated soil sample was treated in continuously stirred flasks in the first set and in fixed bed in the second set and the removal efficiencies were compared. The removal efficiencies obtained indicated the extent of biodegradation for various contaminants, the effect of additional carbon source, and performance in fixed bed without external aeration.

  6. Investigating Electronic Properties of Ionized PAH Clusters

    NASA Astrophysics Data System (ADS)

    Joblin, C.; Kokkin, D.; Bonnamy, A.; Toublanc, D.; Rapacioli, M.; Simon, A.; Dontot, L.; Gamboa, A.; Spiegelman, F.; Parneix, P.; Pino, T.; Pirali, O.; Feraud, G.; Friha, H.; Falvo, C.; Brechignac, P.; Garcia, G.; Nahon, L.; Mulas, G.

    2012-06-01

    Polycyclic aromatic hydrocarbon (PAH) clusters have been proposed as candidates for evaporating very small grains that are revealed by their mid-IR emission at the surface of UV-irradiated clouds in interstellar space. This motivates studies on the photostability and spectroscopic signatures of such species to validate their presence in interstellar environments and constrain their survival therein. We have used the molecular beam chamber SAPHIRS and the photoelectron-photoion coincidence spectrometer DELICIOUS II at the SOLEIL synchrotron facility to characterize the electronic properties of cationic coronene (C24H12) clusters up to the pentamer. These experimental results are analysed in the light of electronic structure calculations. In particular a Density Functional Tight Binding + Configuration Interaction scheme is developed to describe charge delocalization in these large systems and calculate the ionization potential, vibrational spectra, and charge transfer excited states. For the coronene dimer cation, complementary measurements are performed with the PIRENEA set-up to quantify some of the electronic transitions, in particular their oscillator strengths that cannot be extracted from the photoelectron spectroscopy. Emphasis will be put on the evolution of the spectra with cluster size. M. Rapacioli, C. Joblin and P. Boissel Astron. & Astrophys. 429, 193-204 (2005) G. Garcia, H. Soldi-Lose and L. Nahon Rev. Sci. Instrum. 80, 023102 (2009) Joint ANR project GASPARIM, ANR-10-BLAN-501 M. Rapacioli, A. Simon, L. Dontot and F. Spiegelman Phys. Status Solidi B 249 (2) 245-258 (2012)

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

  8. Ethanol-enhanced bioremediation of PAH-contaminated soils

    SciTech Connect

    Lee, P.H.; Ong, S.K.; Golchin, J.

    1999-07-01

    Bioremediation of soils contaminated with polycyclic aromatic hydrocarbons (PAHs) is highly challenging because of the low solubility and strong sorption properties of PAHs to soil organic matter. Two PAH-contaminated soils from former manufactured gas plant (MGP) sites were pretreated with ethanol to enhance the bioavailability of PAH compounds. The biodegradation of various PAHs in the pretreated soils was assessed using soil slurry reactor studies. The time needed to degrade 90% of the total PAH in the pretreated soils was at least 5 days faster than soils that were not pretreated with ethanol. A distinctive advantage with the pretreatment of soils with ethanol was the enhanced removal of 4-ring compounds such as chrysene. Approximately 90% of chrysene in the ethanol-treated soils were removed within 15 days while soils without pretreatment needed more than 30 days to obtain similar removal levels. After 35 days of biotreatment in the slurry reactors, approximately 40% of benzo(a)pyrene were removed in the ethanol-treated soils while only 20% were removed in soils not pretreated with ethanol.

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

    NASA Technical Reports Server (NTRS)

    Hudgins, Douglas M.

    2005-01-01

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

  10. Biogeochemical Approaches to Assess PAH Pollution in an Urban Waterway.

    PubMed

    Cheng, Xianhao; Forsythe, Jennifer; Peterkin, Earl

    2015-12-01

    Biogeochemical approaches were applied to enhance the study on polycyclic aromatic hydrocarbon (PAH) pollution in an urban waterway. Chemical characterizations of PAHs in the studied area were identified, geochemical factors were revealed, and related mechanisms were discussed. It was found that, during summer, an early diagenetic process in the sediment could play a major role for the existence of high PAH concentrations, especially high molecular weight PAHs (≥ 4 rings), in the water column and sediment porewater. This effect could vary with tidal cycling, and higher PAH concentration in the water column would be expected during low tide. Other potential pollution sources were also evaluated in the studied creek. Results showed that pyrogenic sources dominated in the creek, generally. Nevertheless, petroleum products from a metal recycling plant could be an important point source to the waterway during wet weather. Comparing with previous studies in other waterways of the same watershed and published literature suggested that the limited toxicity to the ecosystem was only detected in sediments. More information needs to be collected during low tide for a more objective evaluation of PAH toxicity in the creek. PMID:26579786

  11. PAHs in dated sediments of Ashtabula River, Ohio, USA.

    PubMed

    Li, K; Christensen, E R; Van Camp, R P; Imamoglu, I

    2001-07-15

    Polycyclic aromatic hydrocarbons (PAHs) in dated sediments from Ashtabula River, Ohio, were determined, and a chemical mass balance (CMB) model was used to apportion sources. Three cores (AR-1,AR-2,AR-3) were dated by correlating uranium-supported 210Pb peaks with 1964, 1972, 1977, and 1979 maxima in the discharge record for Ashtabula River. These cores had sedimentation rates between 7.1 and 4.4 cm/year, while a fourth (AR-4) exhibited a much higher rate of 27.8 +/- 18 cm/year. The highest PAH concentration was 11,500 ng/g found in layer 6 of AR-1 (1986), and the lowest was 621 ng/g found in layer 8 of AR-2 (1982). The source contributions to the total PAH concentrations estimated by the CMB model are 0.1-2.2%, 16.8-22.8%, and 78.1-83.8% for wood burning (WB), coke oven (CO), and highway dust (HWY), respectively. Petroleum generated PAHs have maximal contribution during 1977-79, and wood burning PAHs show minimal emissions during 1975-77 in accordance with U.S. consumption records and other studies. Among six PAH markers, only phenanthrene may be subjected to aerobic biodegradation or photolysis with an apparent half-life of 0.005-0.025 year. No anaerobic degradation was observed based on the CMB model. The model works well for the nonmarker compounds, fluoranthene, and benzo[b]fluoranthene/benzo[k]fluoranthene. PMID:11478240

  12. Infrared analysis of flame-generated PAH samples

    SciTech Connect

    McKinnon, J.T.; Meyer, E.; Howard, J.B.

    1996-04-01

    Recent experimental observations support the hypothesis that soot nucleation occurs through the reactive coagulation of polycyclic aromatic hydrocarbons (PAH). The PAH are rapidly formed in the region of a flame just ahead of the soot nucleation zone, which is most commonly defined as the onset of yellow luminosity in a premixed laminar flame. At the point of soot nucleation, the PAH concentration rapidly drops, indicating that PAH dynamics may be intimately linked to soot nucleation. Although one has some understanding of the dynamics of the PAH in sooting flames very little is known about their molecular structure. For example, do these PAH have alkyl groups on peripheral carbons, do they contain oxygen functionalities, etc.? One of the causes of the lack of structural information is that these materials do not lend themselves to convenient analysis due to their low solubility, thermal instability and difficulty in collection. In addition, standards are not generally available. In this paper the authors report on the use of infrared analysis to provide some insight into the structure of these large compounds.

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

    USGS Publications Warehouse

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

    2014-01-01

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

  14. Surface chemistry but not aspect ratio mediates the biological toxicity of gold nanorods in vitro and in vivo.

    PubMed

    Wan, Jiali; Wang, Jia-Hong; Liu, Ting; Xie, Zhixiong; Yu, Xue-Feng; Li, Wenhua

    2015-01-01

    Gold nanorods are a promising nanoscale material in clinical diagnosis and treatment. The physicochemical properties of GNRs, including size, shape and surface features, are crucial factors affecting their cytotoxicity. In this study, we investigated the effects of different aspect ratios and surface modifications on the cytotoxicity and cellular uptake of GNRs in cultured cells and in mice. The results indicated that the surface chemistry but not the aspect ratio of GNRs mediates their biological toxicity. CTAB-GNRs with various aspect ratios had similar abilities to induce cell apoptosis and autophagy by damaging mitochondria and activating intracellular reactive oxygen species (ROS). However, GNRs coated with CTAB/PSS, CTAB/PAH, CTAB/PSS/PAH or CTAB/PAH/PSS displayed low toxicity and did not induce cell death. CTAB/PAH-coated GNRs caused minimally abnormal cell morphology compared with CTAB/PSS and CTAB/PSS/PAH coated GNRs. Moreover, the intravenous injection of CTAB/PAH GNRs enabled the GNRs to reach tumor tissues through blood circulation in animals and remained stable, with a longer half-life compared to the other GNRs. Therefore, our results demonstrated that further coating can prevent cytotoxicity and cell death upon CTAB-coated GNR administration, similar to changing the GNR aspect ratio and CTAB/PAH coated GNRs show superior biological properties with better biocompatibility and minimal cytotoxicity. PMID:26096816

  15. Surface chemistry but not aspect ratio mediates the biological toxicity of gold nanorods in vitro and in vivo

    PubMed Central

    Wan, Jiali; Wang, Jia-Hong; Liu, Ting; Xie, Zhixiong; Yu, Xue-Feng; Li, Wenhua

    2015-01-01

    Gold nanorods are a promising nanoscale material in clinical diagnosis and treatment. The physicochemical properties of GNRs, including size, shape and surface features, are crucial factors affecting their cytotoxicity. In this study, we investigated the effects of different aspect ratios and surface modifications on the cytotoxicity and cellular uptake of GNRs in cultured cells and in mice. The results indicated that the surface chemistry but not the aspect ratio of GNRs mediates their biological toxicity. CTAB-GNRs with various aspect ratios had similar abilities to induce cell apoptosis and autophagy by damaging mitochondria and activating intracellular reactive oxygen species (ROS). However, GNRs coated with CTAB/PSS, CTAB/PAH, CTAB/PSS/PAH or CTAB/PAH/PSS displayed low toxicity and did not induce cell death. CTAB/PAH-coated GNRs caused minimally abnormal cell morphology compared with CTAB/PSS and CTAB/PSS/PAH coated GNRs. Moreover, the intravenous injection of CTAB/PAH GNRs enabled the GNRs to reach tumor tissues through blood circulation in animals and remained stable, with a longer half-life compared to the other GNRs. Therefore, our results demonstrated that further coating can prevent cytotoxicity and cell death upon CTAB-coated GNR administration, similar to changing the GNR aspect ratio and CTAB/PAH coated GNRs show superior biological properties with better biocompatibility and minimal cytotoxicity. PMID:26096816

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

    PubMed

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

    2014-01-01

    The natural biodegradation of seven polycyclic aromatic hydrocarbons (PAHs) by native microorganisms was studied in five soils from Normandy (France) from diffusely polluted areas, which can also pose a problem in terms of surfaces and amounts of contaminated soils. Bioavailability tests using cyclodextrin-based extractions were performed. The natural degradation of low molecular weight (LMW) PAHs was not strongly correlated to their bioavailability due to their sorption to geosorbents. Conversely, the very low degradation of high molecular weight (HMW) PAHs was partly correlated to their poor availability, due to their sorption on complexes of organic matter and kaolinites or smectites. A principal component analysis allowed us to distinguish between the respective degradation behaviors of LMW and HMW PAHs. LMW PAHs were degraded in less than 2-3 months and were strongly influenced by the relative percentage of phenanthrene-degrading bacteria over total bacteria in soils. HMW PAHs were not significantly degraded, not only because they were less bioavailable but also because of a lack of degrading microorganisms. Benzo[a]pyrene stood apart since it was partly degraded in acidic soils, probably because of a catabolic cooperation between bacteria and fungi. PMID:24671402

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

    SciTech Connect

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

    2009-08-15

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

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

    PubMed

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

    2007-04-01

    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

  19. Passive samplers accurately predict PAH levels in resident crayfish.

    PubMed

    Paulik, L Blair; Smith, Brian W; Bergmann, Alan J; Sower, Greg J; Forsberg, Norman D; Teeguarden, Justin G; Anderson, Kim A

    2016-02-15

    Contamination of resident aquatic organisms is a major concern for environmental risk assessors. However, collecting organisms to estimate risk is often prohibitively time and resource-intensive. Passive sampling accurately estimates resident organism contamination, and it saves time and resources. This study used low density polyethylene (LDPE) passive water samplers to predict polycyclic aromatic hydrocarbon (PAH) levels in signal crayfish, Pacifastacus leniusculus. Resident crayfish were collected at 5 sites within and outside of the Portland Harbor Superfund Megasite (PHSM) in the Willamette River in Portland, Oregon. LDPE deployment was spatially and temporally paired with crayfish collection. Crayfish visceral and tail tissue, as well as water-deployed LDPE, were extracted and analyzed for 62 PAHs using GC-MS/MS. Freely-dissolved concentrations (Cfree) of PAHs in water were calculated from concentrations in LDPE. Carcinogenic risks were estimated for all crayfish tissues, using benzo[a]pyrene equivalent concentrations (BaPeq). ∑PAH were 5-20 times higher in viscera than in tails, and ∑BaPeq were 6-70 times higher in viscera than in tails. Eating only tail tissue of crayfish would therefore significantly reduce carcinogenic risk compared to also eating viscera. Additionally, PAH levels in crayfish were compared to levels in crayfish collected 10years earlier. PAH levels in crayfish were higher upriver of the PHSM and unchanged within the PHSM after the 10-year period. Finally, a linear regression model predicted levels of 34 PAHs in crayfish viscera with an associated R-squared value of 0.52 (and a correlation coefficient of 0.72), using only the Cfree PAHs in water. On average, the model predicted PAH concentrations in crayfish tissue within a factor of 2.4±1.8 of measured concentrations. This affirms that passive water sampling accurately estimates PAH contamination in crayfish. Furthermore, the strong predictive ability of this simple model suggests that it could be easily adapted to predict contamination in other shellfish of concern. PMID:26674706

  20. Behavior of PAHs from sewage sludge incinerators in Korea.

    PubMed

    Park, Jung Min; Lee, Sang Bo; Kim, Jin Pil; Kim, Min Jung; Kwon, Oh Sang; Jung, Dong Il

    2009-02-01

    Although production of sewage sludge increases every year, its proper treatment has only been recently raised as a new issue, as current landfill and ocean dumping arrangements are expected to become increasingly difficult to manage in the future. The Korean Ministry of Environment plans to diversify its processing facilities and expand its processing systems by 2011, with the purpose of processing all sludge produced in Korea. According to this plan, incineration (including incineration of municipal wastes) will process 30% of the entire sewage sludge throughout the country in 2011. This study reviews the characteristics of PAH, which is one of the organic substances found in sewage sludge during the incinerating process. The total amount of PAH produced from sewage sludge incineration was found to be 6.103 mg/kg on average, and investigation performed on 16 PAHs of inlets and outlets of the air control devices at five full-scale incineration facilities showed that concentrations of the PAHs on the inlet and on the outlet ranged from 3.926 to 925.748 microg/m(3) and from 1.153 to 189.449 microg/m(3), respectively. In the case of the incineration facility fed with municipal waste (95%) and sewage sludge (5%), the total of the PAH emissions concentration was higher than that found at the incineration facilities used exclusively to treat sewage. The combustion of waste vinyl and plastics contained in municipal waste fed into the facility might contribute to the high levels of PAHs in the stack gas. However more investigation is needed on the production mechanism of PAHs at different operating conditions of the incineration facilities, such as the types of waste, and other relevant factors. PMID:18951779

  1. Toxicity and photoactivation of PAH mixtures in marine sediment

    SciTech Connect

    Swartz, R.; Ferraro, S.; Lamberson, J.; Cole, F.; Ozretich, R.; Boese, B.; Schults, D.; Behrenfeld, M.; Ankley, G.

    1995-12-31

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

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

    PubMed

    Bustnes, Jan O

    2013-08-01

    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

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

    PubMed

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

    2014-05-01

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

  4. SOURCE APPORTIONMENT OF POLYCYCLIC AROMATIC HYDROCARBONS (PAHs) INTO CENTRAL PARK LAKE, NEW YORK CITY, OVER A CENTURY OF DEPOSITION

    PubMed Central

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

    2014-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    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 averagestandard deviation values of 0.1270.241 ng m -3 and 0.2390.546 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 averagestandard deviation values 1.051.88 ng m -3 and 0.8390.713 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.

  6. 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

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

    2009-01-01

    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.

  7. 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

    NASA Astrophysics Data System (ADS)

    Migaszewski, Zdzis?aw M.; Ga?uszka, Agnieszka; Crock, James G.; Lamothe, Paul J.; Do??gowska, Sabina

    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.

  8. 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

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

    2010-12-01

    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

  9. PAH formation in O-rich planetary nebulae

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

  10. PAH Formation in O-rich Evolved Stars

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

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

  11. Induction of PAH degradation in a phenanthrene-degrading pseudomonad

    SciTech Connect

    Stringfellow, W.T.; Chen, S.H.; Aitken, M.D.

    1995-12-31

    Recent evidence suggests that different polycyclic aromatic hydrocarbon (PAH) substrates are metabolized by common enzymes in PAH-degrading bacteria, implying that inducers for low-molecular-weight PAH degradation may coinduce for the metabolism of higher-molecular-weight compounds. The authors have tested this hypothesis with a well-characterized PAH-degrading bacterium, Pseudomonas saccharophila P-15. Growth of P-15 on salicylate, a metabolite of phenanthrene degradation, and a known inducer for naphthalene degradation, induced the metabolism of both substrates. Several potential inducers were then tested for their effects on metabolism of the four-ring compounds pyrene and fluoranthene, neither of which is a growth substrate for P-15, but both of which can be metabolized by this organism. Incubation of P-15 in the presence of phenanthrene or salicylate induced the metabolism of pyrene and fluoranthene in resting-cell assays. Catechol, another intermediate of naphthalene and phenanthrene degradation, did not induce the metabolism of either compound and interfered with the inducing effect of salicylate. These results have implications for strategies designed to maintain PAH degradation in contaminated environments, particularly for compounds that are degraded slowly or are degraded only by nongrowth metabolism.

  12. Contamination of cachaa by PAHs from storage containers.

    PubMed

    de R Machado, Ana Maria; Cardoso, Maria das Graas; Drea, Haroldo S; Emdio, Elissandro S; Silva, Marcell M S; dos Anjos, Jeancarlo P; Saczk, Adelir Aparecida; Nelson, David L

    2014-03-01

    Cachaa 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 cachaas 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 cachaa stored in glass jugs was 6.07?gL(-)(1). These results indicate that the polyethylene tank is a source for PAHs in cachaa. PMID:24176314

  13. LABORATORY PHOTO-CHEMISTRY OF PAHS: IONIZATION VERSUS FRAGMENTATION

    PubMed Central

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

    2015-01-01

    Interstellar Polycyclic Aromatic Hydrocarbons (PAH) are expected to be strongly processed by Vacuum Ultra-Violet (VUV) photons. Here, we report experimental studies on the ionization and fragmentation of coronene (C24H12), ovalene (C32H14) and hexa-peri-hexabenzocoronene (HBC; C42H18) cations by exposure to synchrotron radiation in the range of 840 eV. The results show that for small PAH cations such as coronene, fragmentation (H-loss) is more important than ionization. However, as the size increases, ionization becomes more and more important and for the HBC cation, ionization dominates. These results are discussed and it is concluded that, for large PAHs, fragmentation only becomes important when the photon energy has reached the highest ionization potential accessible. This implies that PAHs are even more photo-stable than previously thought. The implications of this experimental study for the photo-chemical evolution of PAHs in the interstellar medium (ISM) are briefly discussed. PMID:26688710

  14. Consistent dust and gas models for protoplanetary disks. I. Disk shape, dust settling, opacities, and PAHs

    NASA Astrophysics Data System (ADS)

    Woitke, P.; Min, M.; Pinte, C.; Thi, W.-F.; Kamp, I.; Rab, C.; Anthonioz, F.; Antonellini, S.; Baldovin-Saavedra, C.; Carmona, A.; Dominik, C.; Dionatos, O.; Greaves, J.; Güdel, M.; Ilee, J. D.; Liebhart, A.; Ménard, F.; Rigon, L.; Waters, L. B. F. M.; Aresu, G.; Meijerink, R.; Spaans, M.

    2016-02-01

    We propose a set of standard assumptions for the modelling of Class II and III protoplanetary disks, which includes detailed continuum radiative transfer, thermo-chemical modelling of gas and ice, and line radiative transfer from optical to cm wavelengths. The first paper of this series focuses on the assumptions about the shape of the disk, the dust opacities, dust settling, and polycyclic aromatic hydrocarbons (PAHs). In particular, we propose new standard dust opacities for disk models, we present a simplified treatment of PAHs in radiative equilibrium which is sufficient to reproduce the PAH emission features, and we suggest using a simple yet physically justified treatment of dust settling. We roughly adjust parameters to obtain a model that predicts continuum and line observations that resemble typical multi-wavelength continuum and line observations of Class II T Tauri stars. We systematically study the impact of each model parameter (disk mass, disk extension and shape, dust settling, dust size and opacity, gas/dust ratio, etc.) on all mainstream continuum and line observables, in particular on the SED, mm-slope, continuum visibilities, and emission lines including [OI] 63 μm, high-J CO lines, (sub-)mm CO isotopologue lines, and CO fundamental ro-vibrational lines. We find that evolved dust properties, i.e. large grains, often needed to fit the SED, have important consequences for disk chemistry and heating/cooling balance, leading to stronger near- to far-IR emission lines in general. Strong dust settling and missing disk flaring have similar effects on continuum observations, but opposite effects on far-IR gas emission lines. PAH molecules can efficiently shield the gas from stellar UV radiation because of their strong absorption and negligible scattering opacities in comparison to evolved dust. The observable millimetre-slope of the SED can become significantly more gentle in the case of cold disk midplanes, which we find regularly in our T Tauri models. We propose to use line observations of robust chemical tracers of the gas, such as O, CO, and H2, as additional constraints to determine a number of key properties of the disks, such as disk shape and mass, opacities, and the dust/gas ratio, by simultaneously fitting continuum and line observations.

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

    NASA Technical Reports Server (NTRS)

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

    1999-01-01

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

  16. Spitzer Observations of Extraplanar PAH Emission from Spiral Galaxies

    NASA Astrophysics Data System (ADS)

    Lehner, N.; Howk, J.

    We present Spitzer/IRAC observations of polycylic aromatic hydrocarbon (PAH) emission from interstellar material in the thick disks of normal spiral galaxies. These data show PAHs to be a common constituent of extraplanar material in spirals. The processes that displace this material from the interstellar disks of these systems do not destroy these very small grains. The dust emission features are present far above the galactic planes, extended up to about 2-4 kpc above the midplanes of the galaxies presented in this work. The total extent for which dust can be traced is about half the extent of the DIG. If it is not a sensitivity effect, this suggests that PAHs may be associated with a cold neutral medium that can not be supported at high z.

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

    PubMed

    d'Hendecourt, L; Ehrenfreund, P

    1997-01-01

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

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

    PubMed

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

    2007-01-01

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

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

    PubMed Central

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

    1996-01-01

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

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

    SciTech Connect

    Talaska, G.; Underwood, P.; Maier, A.

    1996-10-01

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

  1. Global time trends in PAH emissions from motor vehicles

    PubMed Central

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

    2013-01-01

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

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

    SciTech Connect

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

    1994-12-31

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

  3. Use of alternative growth substrates to enhance PAH degradation

    SciTech Connect

    Tittle, P.C.; Liu, Y.T.; Strand, S.E.; Stensel, H.D.

    1995-12-31

    Freshwater and saltwater polycyclic aromatic hydrocarbons (PAH)-degrading enrichments were developed from seed from a manufactured gas plant site and contaminated marine sediment, respectively. Both enrichments were able to maintain specific degradation rates of 3- and 4-ring PAHs after growth with salicylate or phthalate, which increased their biomass concentrations by a factor of 9 to 10. Phthalate was a more effective alternative substrate than was salicylate. Specific degradation rates of phenanthrene and anthracene by the freshwater enrichment were increased after growth with phthalate. Growth with phthalate increased the specific degradation rates of phenanthrene and pyrene by the saltwater enrichment.

  4. Biodegradation of PAHs and PCBs in soils and sludges

    USGS Publications Warehouse

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

    2007-01-01

    Results from a multi-year, pilot-scale land treatment project for PAHs and PCBs biodegradation were evaluated. A mathematical model, capable of describing sorption, sequestration, and biodegradation in soil/water systems, is applied to interpret the efficacy of a sequential active-passive biotreatment process of organic chemicals on remediation sites. To account for the recalcitrance of PAHs and PCBs in soils and sludges during long-term biotreatment, this model comprises a kinetic equation for organic chemical intraparticle sequestration process. Model responses were verified by comparison to measurements of biodegradation of PAHs and PCBs in land treatment units; a favorable match was found between them. Model simulations were performed to predict on-going biodegradation behavior of PAHs and PCBs in land treatment units. Simulation results indicate that complete biostabilization will be achieved when the concentration of reversibly sorbed chemical (S RA) reduces to undetectable levels, with a certain amount of irreversibly sequestrated residual chemical (S IA) remaining within the soil particle solid phase. The residual fraction (S IA) tends to lose its original chemical and biological activity, and hence, is much less available, toxic, and mobile than the "free" compounds. Therefore, little or no PAHs and PCBs will leach from the treatment site and constitutes no threat to human health or the environment. Biotreatment of PAHs and PCBs can be terminated accordingly. Results from the pilot-scale testing data and model calculations also suggest that a significant fraction (10-30%) of high-molecular-weight PAHs and PCBs could be sequestrated and become unavailable for biodegradation. Bioavailability (large K d , i.e., slow desorption rate) is the key factor limiting the PAHs degradation. However, both bioavailability and bioactivity (K in Monod kinetics, i.e., number of microbes, nutrients, and electron acceptor, etc.) regulate PCBs biodegradation. The sequential active-passive biotreatment can be a cost-effective approach for remediation of highly hydrophobic organic contaminants. The mathematical model proposed here would be useful in the design and operation of such organic chemical biodegradation processes on remediation sites. ?? 2007 Springer Science+Business Media B.V.

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

    SciTech Connect

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

    1984-11-01

    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.

  6. Distribution of persistent organic pollutants (PAHs, Me-PAHs, PCBs) in dissolved, particulate and sedimentary phases in freshwater systems.

    PubMed

    Rabodonirina, Suzanah; Net, Sopheak; Ouddane, Baghdad; Merhaby, Dima; Dumoulin, David; Popescu, Tudor; Ravelonandro, Pierre

    2015-11-01

    The occurrence of three groups of hazardous organic contaminants (PCBs, PAHs, Me-PAHs) in fifteen watercourses and rivers located in highly urbanized and industrialized zones was studied. The distribution of 62 organic contaminants was determined in three matrices: in the dissolved phase, associated with suspended solid matter (SSM) and in sediment. Their distributions in the aquatic environment depend strongly on their physicochemical properties. Low molecular weight PAHs were predominant in the dissolved phase while those with high molecular weight accumulated preferentially in SSM and sediments. Among the 28 PCBs congeners, only PCB153 was detected. The results showed that the contamination of these areas originated mainly from combustion processes. The three the most polluted sites identified are surrounded by big cities. Ecotoxicological assessment based on the international Sediment Quality Guidelines (SQGs) showed that the toxic effects of the sediment in these watercourses and rivers occurred due to high levels of hydrocarbons. PMID:26142749

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  8. ASSAYING PARTICLE-BOUND POLYCYCLIC AROMATIC HYDROCARBONS (PAH) FROM ARCHIVED PM2.5 FILTERS

    EPA Science Inventory

    Airborne particulate matter contains numerous organic species, including several polycyclic aromatic hydrocarbons (PAHs) that are known or suspected carcinogens. Existing methods for measuring airborne PAHs are complex and costly, primarily because they are designed to collect...

  9. Increased zooplankton PAH concentrations across hydrographic fronts in the East China Sea.

    PubMed

    Hung, Chin-Chang; Ko, Fung-Chi; Gong, Gwo-Ching; Chen, Kuo-Shu; Wu, Jian-Ming; Chiang, Hsin-Lun; Peng, Sen-Chueh; Santschi, Peter H

    2014-06-15

    The Changjiang has transported large quantities of polycyclic aromatic hydrocarbons (PAHs) to the East China Sea (ECS), but information of these pollutants in zooplankton is limited. To understand PAHs pollution in zooplankton in the ECS, total concentrations of PAHs in zooplankton from surface waters were measured. Values of PAHs ranged from 2 to 3500 ng m(-3) in the ECS, with highest PAHs levels located at the salinity front between the Changjiang Diluted Water (CDW) and the mid-shelf waters. In contrast, concentrations of zooplankton PAHs in the mid-shelf and outer-shelf waters were significantly lower (2-23 ng m(-3)) than those in the CDW. These results demonstrate that PAHs are conspicuously accumulated in zooplankton at the salinity front between the CDW and the mid-shelf waters. These higher levels of PAHs in zooplankton at the salinity front may be further biomagnified in marine organisms of higher trophic levels through their feeding activities. PMID:24775063

  10. Biological risk and pollution history of polycyclic aromatic hydrocarbons (PAHs) in Nansha mangrove, South China.

    PubMed

    Wu, Qihang; Leung, Jonathan Y S; Tam, Nora F Y; Chen, Shejun; Mai, Bixian; Zhou, Xizhen; Xia, Lihua; Geng, Xinhua

    2014-08-15

    Chinese government has taken various measures to alleviate pollution caused by polycyclic aromatic hydrocarbons (PAHs) in the region of Pearl River Delta since the economic reform in 1978, but the effectiveness of these measures remains largely unknown. This study aimed to elucidate the biological risk and pollution history of PAHs by measuring the concentrations of 28 PAHs in the surface and core sediments, respectively, in Nansha mangrove. Results found that the biological risk of PAHs was low without obvious spatial variation. The PAH concentration along the depth gradient indicated that PAH pollution was stabilized since the early 1990s while the source of PAHs has gradually changed from combustion of coal to petroleum products. This implied that the mitigation measures taken by the Chinese government were effective. Compared to marine bottom sediment, we propose that using mangrove sediment can provide a more accurate and precise estimate of pollution history of PAHs. PMID:24981104

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

    USGS Publications Warehouse

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

    2012-01-01

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

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

    PubMed

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

    2015-10-01

    Thirty atmospheric dustfall samples collected from an industrial corridor in Hubei Province, central China, were analyzed for 16 USEPA priority polycyclic aromatic hydrocarbons (PAHs) to investigate their concentrations, spatial distributions, sources, and health risks. Total PAH concentrations (?PAHs) ranged from 1.72 to 13.17 g/g and averaged 4.91 g/g. High molecular weight (4-5 rings) PAHs averaged 59.67% of the ?PAHs. Individual PAH concentrations were not significantly correlated with total organic carbon, possibly due to the semi-continuous inputs from anthropogenic sources. Source identification studies suggest that the PAHs were mainly from motor vehicles and biomass/coal combustion. The incremental lifetime cancer risks associated with exposure to PAHs in the dustfall ranged from 10(-4) to 10(-6); these indicate potentially serious carcinogenic risks for exposed populations in the industrial corridor. PMID:25239676

  13. Determination of polycyclic aromatic hydrocarbon (PAH) content and risk assessment from edible oils in Korea.

    PubMed

    Kang, Bomi; Lee, Byung-Mu; Shin, Han-Seung

    2014-01-01

    Polycyclic aromatic hydrocarbons (PAH) content and a risk assessment from consumption of Korean edible oils were investigated. Liquid-liquid extraction and gas chromatography-mass spectroscopy were used to measure eight PAH in edible oils commonly consumed in Korea. The total average PAH concentration was 0.548 ?g/kg from edible oils and the content of the 8 PAH was lower than 2 ?g/kg, which is the maximum tolerable limit reported by the commission regulation. The contents of the eight PAH were converted to exposure assessment and risk characterization values. Dietary exposure to PAH from edible oils was 0.025 ng-TEQBaP/kg/d, and margin of exposure (MOE) was 4 10(6), which represents negligible concern. Although PAH were detected from edible oils in Korea, their contribution to human exposure to PAH is considered not significant. PMID:25343286

  14. 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...

  15. 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...

  16. BIODEGRADATION OF SEDIMENT-BOUND PAHS IN FIELD-CONTAMINATED SEDIMENT

    EPA Science Inventory

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

  17. RISKS TO FISH AND OTHER AQUATIC ORGANISMS FROM PAHS IN NATURAL SYSTEMS

    EPA Science Inventory

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

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

    PubMed

    Wang, Ruwei; Liu, Guijian; Zhang, Jiamei

    2015-12-15

    Coal-fired power plants (CFPPs) represent important source of atmospheric PAHs, however, their emission characterization are still largely unknown. In this work, the concentration, distribution and gas-particle partitioning of PM10- and gas-phase PAHs in flue gas emitted from different coal-fired utility boilers were investigated. Moreover, concentration and distribution in airborne PAHs from different functional areas of power plants were studied. People's inhalatory and dermal exposures to airborne PAHs at these sites were estimated and their resultant lung cancer and skin cancer risks were assessed. Results indicated that the boiler capacity and operation conditions have significant effect on PAH concentrations in both PM10 and gas phases due to the variation of combustion efficiency, whereas they take neglected effect on PAH distributions. The wet flue gas desulphurization (WFGD) takes significant effect on the scavenging of PAH in both PM10 and gas phases, higher scavenging efficiency were found for less volatile PAHs. PAH partitioning is dominated by absorption into organic matter and accompanied by adsorption onto PM10 surface. In addition, different partitioning mechanism is observed for individual PAHs, which is assumed arising from their chemical affinity and vapor pressure. Risk assessment indicates that both inhalation and dermal contact greatly contribute to the cancer risk for CFPP workers and nearby residents. People working in workshop are exposed to greater inhalation and dermal exposure risk than people living in nearby vicinity and working office. PMID:26298851

  19. Fungal Diagnostics

    PubMed Central

    Kozel, Thomas R.; Wickes, Brian

    2014-01-01

    Early diagnosis of fungal infection is critical to effective treatment. There are many impediments to diagnosis such as a diminishing number of clinical mycologists, cost, time to result, and requirements for sensitivity and specificity. In addition, fungal diagnostics must meet the contrasting needs presented by the increasing diversity of fungi found in association with the use of immunosuppressive agents in countries with high levels of medical care and the need for diagnostics in resource-limited countries where large numbers of opportunistic infections occur in patients with AIDS. Traditional approaches to diagnosis include direct microscopic examination of clinical samples, histopathology, culture, and serology. Emerging technologies include molecular diagnostics and antigen detection in clinical samples. Innovative new technologies that use molecular and immunoassay platforms have the potential to meet the needs of both resource-rich and resource-limited clinical environments. PMID:24692193

  20. Evaporation and vapor characterization of low-PAH binders for Soederberg cells

    SciTech Connect

    Eie, M.; Oeye, H.A.; Soerlie, M.

    1996-10-01

    The PAH contents in anode pitches as well as in their pitch vapors have been characterized, for both standard anode pitches and the new types of PAH-reduced cut-back pitches. This data has been compared to PAH emissions measured from industrial VS Soederberg cells. A total of 16 PAH compounds in the pitches, from phenanthrene to dibenzopyrenes, have been analyzed in this work.

  1. CAD spectra of PAHs by ion trap and triple quadrupole mass spectrometry

    SciTech Connect

    Winnik, W.; Betowski, L.; Pyle, S.

    1995-12-31

    Polycyclic aromatic hydrocarbons (PAHs) are common products of many industrial and natural combustion processes. PAHs are found in grilled meat, tobacco smoke, air-borne particulates, used motor oil and soil. They are produced by practically any process involving combustion of fossil fuels. Because many PAHs are carcinogens, the U. S. Environmental Protection Agency (EPA), through its National Exposure Research Laboratory in Las Vegas, NV must develop analytical methods for determining these ubiquitous pollutants. The authors investigated detection of PAHs using CAD MS.

  2. Polycyclic aromatic hydrocarbons (PAHs) at traffic and urban background sites of northern Greece: source apportionment of ambient PAH levels and PAH-induced lung cancer risk.

    PubMed

    Manoli, Evangelia; Kouras, Athanasios; Karagkiozidou, Olga; Argyropoulos, Georgios; Voutsa, Dimitra; Samara, Constantini

    2016-02-01

    Thirteen particle-phase PAHs, including nine >4-ring congeners [Benz[a]anthracene (BaAn), Chrysene (Chry), Benzo[b]fluoranthene (BbF), Benzo[k]fluoranthene (BkF), Benzo[e]pyrene (BeP), Benzo[a]pyrene (BaP), Dibenzo[a,h]anthracene (dBaAn), Benzo[g,h,i]perylene (BghiPe), Indeno(1,2,3-c,d)pyrene (IP)], listed by IARC (International Agency for Research on Cancer) as class 1, class 2A, and 2B carcinogens, plus four ≤4-ring congeners [Phenanthrene (Ph), Anthracene (An), Fluoranthene (Fl), Pyrene (Py)], were concurrently measured in inhalable and respirable particle fractions (PM10 and PM2.5) at a heavy-traffic and an urban background site in Thessaloniki, northern Greece, during the warm and the cold period of the year. Carcinogenic and mutagenic potencies of the PAH-bearing particles were calculated, and the inhalation cancer risk (ICR) for local population was estimated. Finally, Chemical Mass Balance (CMB) modeling was employed for the source apportionment of ambient PAH levels and the estimated lung cancer risk. Resulted inhalation cancer risk during winter was found to be equivalent in the city center and the urban background area suggesting that residential wood burning may offset the benefits from minor traffic emissions. PMID:26490935

  3. Pilot-scale bioremediation of PAH-contaminated soils

    SciTech Connect

    Pradhan, S.P.; Paterek, J.R.; Liu, B.Y.; Conrad, J.R.; Srivastava, V.J.

    1997-12-31

    The Institute of Gas Technology (IGT) conducted a pilot-scale study at a former manufactured gas plant (MGP) site in New Jersey. The objective of the study was to determine the effectiveness of an innovative chemical/biological treatment process (MGP-REM process) to remediate soils contaminated with polynuclear aromatic hydrocarbons (PAHs). In order to identify the benefits of the MGP-REM process, the system was also operated in the conventional bioremediation mode. Results showed that the MGP-REM process can effectively treat PAH-contaminated MGP site soils, and it reduced the toxicity of the soil by a factor of 50, as indicated by the Microtox Toxicity Test. The MGP-REM process was 70% more efficient than conventional bioremediation in the removal of the PAHs from the soils. Air emissions data suggest that minimal air pollution control and monitoring are required for the slurry-phase application of both the MGP-REM process and the conventional biological treatment. Process economics indicate that the MGP-REM process in a slurry-phase mode has an estimated treatment cost of $100/cubic yard for remediation of PAH-contaminated soils. 7 refs., 7 figs., 9 tabs.

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

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

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

  5. Bioremediation of polyaromatic hydrocarbons (PAHs) using rhizosphere technology.

    PubMed

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

    2015-03-01

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

  6. The infrared signatures of non-regular PAHs

    NASA Astrophysics Data System (ADS)

    Pauzat, F.; Ellinger, Y.

    2002-07-01

    In a first approach to the spectral signatures of an irregular carbonaceous matter, we report a theoretical investigation of the infrared spectra of non-regular conjugated hydrocarbons. The series under consideration consists of three-cycle PAHs. Anthracene and phenanthrene are taken as references for regular PAHs and dibenzocyclobutadiene (biphenylene), dibenzocyclopentadienyl (fluorenyl), dibenzocycloheptatrienyl (heptafluorenyl) as models for irregular PAHs. These irregular conjugated hydrocarbons consist of four-, five- and seven- (instead of six) membered rings respectively sandwiched between two benzene entities while the regular ones are built with only six-membered rings. The IR spectra of the neutral, singly and doubly ionized species are compared. It is found that the non-regular compounds present the same general behaviour as regular ones at each level of ionization. From an astrophysical point of view, none of the differences is found big enough to be relevant for selective observation, which implies that all sorts of PAHs including irregular structures may be present and contribute anonymously to the UIR bands.

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  8. PAHs molecules and heating of the interstellar gas

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

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

  9. 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...

  10. LAND TREATMENT OF TWO PLATEAU MATERIALS CONTAMINATED WITH PAHS

    EPA Science Inventory

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

  11. Efficiency of butyl rubber sorbent to remove the PAH toxicity.

    PubMed

    Okay, O S; zdemir, P; Yakan, S D

    2011-01-01

    Large amounts of polycyclic aromatic hydrocarbons (PAHs) have been released to the marine environment as a result of oil spills and from other sources including wastewaters, surface runoff, industrial processes, atmospheric deposition, biosynthesis, and natural events such as forest fires. PAHs have been known to affect a variety of biological processes and can be potent cell mutagens/carcinogens and toxic. In this study, PAH toxicity removal was investigated by using a novel macroporous butyl rubber (BR) sorbent. To find out the toxicity removal efficiency of the sorbents, the toxicity tests with Vibrio fisheri (luminescence bacteria) and Phaeodactylum tricornutum (marine algae) were applied to the acenaphthene (Ace) and phenanthrene (Phen) solutions in seawater (Ace: 500- 1000 ?g/L; Phen; 100-1000 ?g/L) before and after sorbent applications. Additionally, lysosomal stability and filtration rate biomarker techniques were applied to the mussels (Mytilus galloprovincialis) exposed to 1000 ?g/L Phen solution and bioaccumulation was measured. The results showed that the toxicity of the PAH solutions decreased 50-100 percent depending on the concentration of the solutions and organisms. Phaeodactylum was found as the most sensitive organism to Phen and Ace. Since the application of BR sorbent removed the Phen from the solution, the bioaccumulated Phen amount in the mussels decreased accordingly. PMID:21714631

  12. Angular motion of a PAH molecule in interstellar environment

    NASA Technical Reports Server (NTRS)

    Rouan, D.; Leger, Alain; Omont, A.; Giard, Martin

    1989-01-01

    Polycyclic aromatic hydrocarbon (PAH) molecules have recently been proposed as an important and hitherto undetected component of the Interstellar Medium (ISM). The theory was based on an explanation of the Unidentified IR Emission Bands by Leger et al. It has already led to a verified prediction on extended galactic and extragalactic emissions measured by IRAS, or by a recent balloon borne experiment. The physics that rules the motion of such molecules in the ISM was studied, taking into account their coupling with the ambient gas, the radiation field (absorption and emission) and the static magnetic field. This is important for many implications of the PAH theory such as the radio emission by these molecules or the expected polarization of their IR emission. A reflection nebulae is considered where the situation is rather well known. Every day life of a mean PAH molecule in such a region is as follows: every 3 hrs a UV photon is absorbed heating the molecule to a thousand degs; the temperature decay due to cooling by IR emission follows then within a few seconds. A collision with a molecule of gas occurs typically once a week, while an H atom is ejected or captured at the same rate. A typical cooling cycle after a heat impulse is given. The PAH molecules studied as representative of the family has typically 50 atoms, a radius of 4.5 A, is circular and has a molecular mass of M = 300; its permanent dipole moment is 3 Debye.

  13. PAH EXPOSURES OF PRESCHOOL CHILDREN AND THEIR ADULT CAREGIVERS

    EPA Science Inventory

    The results of four small studies of the polycyclic aromatic hydrocarbon (PAH) exposures of preschool children in low-income families from the Piedmont area of North Carolina were combined to allow comparisons of the total exposures of the children and their adult caregivers. I...

  14. Levels, trends and health concerns of atmospheric PAHs in Europe

    NASA Astrophysics Data System (ADS)

    Garrido, Adrin; Jimnez-Guerrero, Pedro; Ratola, Nuno

    2014-12-01

    Changes in climate can affect the concentration patterns of polycyclic aromatic hydrocarbons (PAHs) by altering the dispersion (wind speed, mixing layer height, convective fronts), deposition by precipitation, dry deposition, photochemistry, natural emissions and background concentrations. This means the evolution trends of these pollutants have to be studied under a multi-scale perspective, allowing the establishment of transport patterns and distribution of PAHs. In this sense, this work tries to unveil the atmospheric behaviour of these pollutants using temporal data series collected in different stations from the European Monitoring and Evaluation Programme (EMEP) air sampling network. These sites are thought to avoid the direct influence of emitting areas (background stations), allowing the study of long-range transport effects, intra- and trans-annual variability, relationships between concentrations patterns and meteorological variables and latitudinal gradients of PAH levels in Europe. Overall, a typical high concentration pattern was found for the colder months (and an opposite behaviour is found for summertime). Negative trends were detected over high latitudes, for instance, in Svalbard (Norway), whereas for the United Kingdom the pattern is the inverse. Also, negative latitudinal gradients were observed in 4 of the 15 PAHs studied. Finally, air quality parameters revealed concern over human health issues, given the recent increase of BaP levels in Europe.

  15. 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...

  16. Bioremediation of polyaromatic hydrocarbons (PAHs) using rhizosphere technology

    PubMed Central

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

    2015-01-01

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

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

    EPA Science Inventory

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

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

    PubMed

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

    2005-10-01

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

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

    EPA Science Inventory

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

  20. 75 FR 8937 - Development of a Relative Potency Factor (RPF) Approach for Polycyclic Aromatic Hydrocarbon (PAH...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-26

    ... AGENCY Development of a Relative Potency Factor (RPF) Approach for Polycyclic Aromatic Hydrocarbon (PAH...) Approach for Polycyclic Aromatic Hydrocarbon (PAH) Mixtures'' (EPA/635/R-08/012A). The draft document was... of a Relative Potency Factor (RPF) Approach for Polycyclic Aromatic Hydrocarbon (PAH) Mixtures''...

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

    NASA Astrophysics Data System (ADS)

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

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

  2. BmPAH Catalyzes the Initial Melanin Biosynthetic Step in Bombyx mori

    PubMed Central

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

    2013-01-01

    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. PMID:23991017

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

    PubMed

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

    2007-05-01

    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

  4. PAH depositional history and sources in recent sediment core from Ukwa Ibom Lake, S. E. Nigeria.

    PubMed

    Oyo-Ita, O E; Oyo-Ita, I O

    2013-04-01

    Analyses of recent sediment core from the Ukwa Ibom Lake show evidence of aquatic production, terrigenous, combustion and petroleum inputs. Total organic carbon/total nitrogen values (>10) for the sediments indicate greater wash-in of land-plant organic matter relative to algal production. The characteristic combustion ratios, fluoranthene/fluoranthene+pyrene (>0.50), anthracene/anthracene+phenanthrene (>0.10), benzo(a)anthracene/benzo(a)anthracene+chrysene (>0.35) as well as 1,7/1,7+2,6-dimethylphenanthrene (>0.70) were observed for the top section only. These results coincided with the most recent pave-road extension exercise involving tree logging and burning of bush. The highest total PAH concentration (91.13ng/g dry weight (dw)) observed for the bottom section coincided with the period of inhabitation of the lake catchments (~5 decades ago) when discharge to the Lake water of domestic sewage and mill waste water were prevalent. The regular decline in total PAH concentrations upcore is a reflection of the ban placed on indiscriminate dumping of wastes following relocation of the inhabitants of the catchments. Besides the local depositional history, the irregular decrease in unresolved complex mixture (UCM) profiles suggests regional contaminant influx from the adjacent upper Cross River estuary, especially during intense rainfall event. The non-uniformity in methylphenanthrene indices (MPI-1 and MPI-2) shows evidence of importation and utilization of petroleum products of different thermal maturity histories into the Nigerian economy. PMID:22821212

  5. Current and historical deposition of PBDEs, pesticides, PCBs, and PAHs to Rocky Mountain National Park.

    PubMed

    Usenko, Sascha; Landers, Dixon H; Appleby, Peter G; Simonich, Staci L

    2007-11-01

    An analytical method was developed for the trace analysis of 98 semivolatile organic compounds (SOCs) in remote, high-elevation lake sediment. Sediment cores from Lone Pine Lake (west of the Continental Divide) and Mills Lake (east of the Continental Divide) in Rocky Mountain National Park, CO, were dated using 210Pb and 137Cs and analyzed for polybrominated diphenyl ethers (PBDEs), organochlorine pesticides, phosphorothioate pesticides, thiocarbamate pesticides, amide herbicides, triazine herbicides, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs) using this method. SOC deposition profiles were reconstructed, and deposition half-lives and doubling times were calculated, for U.S. historic-use pesticides (HUPs) and current-use pesticides (CUPs) as well as PBDEs, PCBs, and PAHs. Sediment records indicate that the deposition of CUPs has increased in recent years, while the deposition of HUPs has decreased since U.S. restriction, but has not been eliminated. This is likely due to the revolatilization of HUPs from regional soils, atmospheric transport, and deposition. Differences in the magnitude of SOC sediment fluxes, flux profiles, time trends within those profiles, and isomeric ratios suggest that SOC deposition in high-elevation ecosystems is dependent on regional upslope wind directions and site location with respect to regional sources and topographic barriers. PMID:18044494

  6. Diagnostic imaging.

    PubMed

    Morris, Peter; Perkins, Alan

    2012-04-21

    Physical techniques have always had a key role in medicine, and the second half of the 20th century in particular saw a revolution in medical diagnostic techniques with the development of key imaging instruments: x-ray imaging and emission tomography (nuclear imaging and PET), MRI, and ultrasound. These techniques use the full width of the electromagnetic spectrum, from gamma rays to radio waves, and sound. In most cases, the development of a medical imaging device was opportunistic; many scientists in physics laboratories were experimenting with simple x-ray images within the first year of the discovery of such rays, the development of the cyclotron and later nuclear reactors created the opportunity for nuclear medicine, and one of the co-inventors of MRI was initially attempting to develop an alternative to x-ray diffraction for the analysis of crystal structures. What all these techniques have in common is the brilliant insight of a few pioneering physical scientists and engineers who had the tenacity to develop their inventions, followed by a series of technical innovations that enabled the full diagnostic potential of these instruments to be realised. In this report, we focus on the key part played by these scientists and engineers and the new imaging instruments and diagnostic procedures that they developed. By bringing the key developments and applications together we hope to show the true legacy of physics and engineering in diagnostic medicine. PMID:22516558

  7. Plasma processing of interstellar PAHs into solar system kerogen

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

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

  8. Plasma processing of interstellar PAHs into solar system kerogen

    NASA Astrophysics Data System (ADS)

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

    1995-02-01

    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.

  9. Plasma processing of interstellar PAHs into solar system kerogen.

    PubMed

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

    1995-01-01

    Processes resulting in the formation of hydrocarbons of carbonaceous chondrites and the identity of the interstellar molecular precursors involved are an objective of investigations into the origin of the solar system and perhaps even life on earth. We have combined the resources and experience of an astronomer and physicists doing laboratory simulations with those of a chemical expert in the analysis of meteoritic hydrocarbons, in a project that investigated the conversion of polycyclic aromatic hydrocarbons (PAHs) formed in stellar atmospheres into alkanes found in meteorites. Plasma hydrogenation has been found in the University of Alabama at Birmingham Astrophysics Laboratory to produce from the precursor PAH naphthalene, a new material having an IR absorption spectrum (Lee, W. and Wdowiak, T.J., Astrophys. J. 417, L49-L51, 1993) remarkably similar to that obtained at Arizona State University of the benzene-methanol extract of the Murchison meteorite (Cronin, J.R. and Pizzarello, S., Geochim. Cosmochim. Acta 54, 2859-2868, 1990). There are astrophysical and meteoritic arguments for PAH species from extra-solar sources being incorporated into the solar nebula, where plasma hydrogenation is highly plausible. Conversion of PAHs into alkanes could also have occurred in the interstellar medium. The synthesis of laboratory analogs of meteoritic hydrocarbons through plasma hydrogenation of PAH species is underway, as is chemical analysis of those analogs. The objective is to clarify this heretofore uninvestigated process and to understand its role during the origin of the solar system as a mechanism of production of hydrocarbon species now found in meteorites. Results have been obtained in the form of time-of-flight spectroscopy and chemical analysis of the lab analog prepared from naphthalene. PMID:11540308

  10. Sedimentary record of anthropogenic contaminants (trace metals and PAHs) and organic matter in a Mediterranean coastal area (Gulf of Palermo, Italy)

    NASA Astrophysics Data System (ADS)

    Di Leonardo, Rossella; Vizzini, Salvatrice; Bellanca, Adriana; Mazzola, Antonio

    2009-08-01

    The Gulf of Palermo (Italy, Mediterranean Sea) is a contaminated coastal environment with a relatively high influx of unregulated industrial and domestic effluents. Two sediment box-cores were collected at water depths of 100 and 712 m. Samples were analysed for trace metals (As, Cu, Hg, Mn, Ni, Pb), total polycyclic aromatic hydrocarbons (?PAHs), organic carbon to total nitrogen (C org/N tot) ratios and organic carbon and nitrogen isotopic composition ( ?13C org and ?15N tot). At the coastal site, trace metal and ?PAH depth profiles show a clear upcore increase, indicating increasing contamination over the recent past. Concentrations of ?PAHs, Hg, Pb, Cu, and As appear to be potentially hazardous, far exceeding national and international regulatory guidelines. C org/N tot ratios and ?13C org indicate the marine origin of organic matter, supporting eutrophication rather than direct land runoff as principal carbon source. The distal site exhibits lesser contaminant input and minor anthropogenic influence. On the whole, sedimentary records were reliable indicators of recent metal and ?PAH contamination and organic enrichment.

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

    SciTech Connect

    Simon, A.; Joblin, C.

    2010-03-20

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2011-05-01

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

  13. Modeling the Infrared Emission Spectra of Specific PAH Molecules in Interstellar Space

    NASA Astrophysics Data System (ADS)

    Li, Aigen

    2007-05-01

    The 3.3, 6.2, 7.7, 8.6 and 11.3 micron emission features ubiquitously seen in a wide variety of Galactic and extragalactic objects, are generally attributed to polycyclic aromatic hydrocarbon (PAH) molecules. Although the PAH hypothesis is quite successful in explaining the general pattern of the observed emission spectra, so far there is no actual precise identification of a single specific PAH molecule in interstellar space. Therefore, when modeling the observed PAH emission spectra, astronomers usually take an empirical approach by constructing 'astro-PAHs' which do not represent any specific material, but approximate the actual absorption properties of the PAH mixture in astrophysical regions. We propose a Spitzer Theory Program to study the photoexcitation of specific PAH molecules and their ions in interstellar space, taking a statistical-mechanical (instead of thermal) approach. For most of the specific PAH molecules selected for this research (with a small number of vibrational degrees of freedom), thermal approximation is not valid. Using available laboratory and quantum-chemical data (e.g. vibrational frequencies, UV/visible/IR absorption cross sections), we will calculate the emission spectra of 21 representative specific PAH molecules and their ions, ranging from naphthalene to circumcoronene, illuminated by interstellar radiation fields of a wide range of intensities. This program will create a web-based 'library' of the emission spectra of 21 specific PAH molecules and their ions as a function of starlight intensities. This 'library' will be made publicly available by October 2008 on the internet at http://www.missouri.edu/~lia/. By comparing observed PAH spectra with model spectra produced by co-adding the emission spectra of different PAH molecules available in this 'library' (with different weights for different species), one will be able to estimate the total PAH mass and relative abundances of each PAH species, using real PAH properties.

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

    PubMed

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

    2010-06-01

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

  15. Particle-scale investigation of PAH desorption kinetics and thermodynamics from sediment.

    PubMed

    Ghosh, U; Talley, J W; Luthy, R G

    2001-09-01

    Dredged sediment from Milwaukee Harbor showed two primary classes of particles in the <2 mm size range: a lighter-density coal- and wood-derived fraction with 62% of total PAHs and a heavier-density sand, silt, and clay fraction containing the remaining 38% of the PAHs. Room-temperature PAH desorption kinetic studies on separated sediment fractions revealed slow desorption rates for the coal-derived particles and fast desorption rates for the clay/silt particles. The effect of temperature on PAH release was measured by thermal program desorption mass spectrometry to investigate the desorption activation energies for PAHs on the different sediment particles. Three activated diffusion-based models and an activated first-order rate model were used to describe the thermal desorption of PAHs for four molecular weight classes. PAH binding with the coal-derived particles was associated with high activation energies, typically in the range of 115-139 kJ/mol. PAHs bound to the clay/silt material had much lower activation energy, i.e., in the range of 37-41 kJ/ mol for molecular weight 202. Among the desorption models tested, a spherical diffusion model with PAHs located like a rind on the outer 1-3 microm region best described the PAH thermal desorption response for coal-derived particles. This internal PAH distribution pattern on coalderived particles is based on prior direct measurement of PAH locations at the subparticle scale. These studies reveal that heterogeneous particle types in sediment exhibit much different amounts and binding of PAHs. PAHs associated with coal-derived particles aged over several decades in the field appear to be far from reaching an equilibrium sorption state due to the extremely slow diffusivities through the polymer-like coal matrix. These results provide an improved mechanistic perspective for the understanding of PAH mobility and bioavailability in sediments. PMID:11563648

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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

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

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

    SciTech Connect

    Cook, Amanda M.; Mattioda, Andrew L.; Roser, Joseph; Bregman, Jonathan; Bouwman, Jordy; Linnartz, Harold

    2015-01-20

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

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

    PubMed

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

    2008-01-15

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

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

    PubMed Central

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

    2015-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

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

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

    PubMed

    Zhang, Wanhui; Wei, Chaohai; An, Guanfeng

    2015-05-01

    In this study, we report the performance of a full-scale conventional activated sludge (A-O1-O2) treatment in eliminating polycyclic aromatic hydrocarbons (PAHs). Both aqueous and solid phases along with the coking wastewater treatment processes were analyzed for the presence of 18 PAHs. It was found that the target compounds occurred widely in raw coking wastewater, treated effluent and sludge samples. In the coking wastewater treatment system, 4-5 ring PAHs were the dominant compounds, while 4 rings PAHs predominated in the sludge samples. Over 98% of the PAH removal was achieved in the coking wastewater treatment plant (WWTP), with the total concentration of PAHs being 21.3 1.9 ?g L(-1) in the final effluent. During the coking wastewater treatment processes, the association of the lower molecular weight PAH with suspended solids was generally less than 60%, while the association of higher molecular weight PAHs was greater than 90%. High distribution efficiencies (Kdp and Kds) were found, suggesting that adsorption was the potential removal pathway of PAHs. Finally, the mass balances of PAHs in various stages of the coking WWTP were obtained, and the results indicated that adsorption to sludge was the main removal pathway for PAHs in the coking wastewater treatment processes. PMID:25865172

  2. Polycyclic Aromatic Hydrocarbons (PAHs) and their Bioaccessibility in Meat: a Tool for Assessing Human Cancer Risk.

    PubMed

    Hamidi, Elliyana Nadia; Hajeb, Parvaneh; Selamat, Jinap; Abdull Razis, Ahmad Faizal

    2016-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are primarily formed as a result of thermal treatment of food, especially barbecuing or grilling. Contamination by PAHs is due to generation by direct pyrolysis of food nutrients and deposition from smoke produced through incomplete combustion of thermal agents. PAHs are ubiquitous compounds, well-known to be carcinogenic, which can reach the food in different ways. As an important human exposure pathway of contaminants, dietary intake of PAHs is of increasing concern for assessing cancer risk in the human body. In addition, the risks associated with consumption of barbecued meat may increase if consumers use cooking practices that enhance the concentrations of contaminants and their bioaccessibility. Since total PAHs always overestimate the actual amount that is available for absorption by the body, bioaccessibility of PAHs is to be preferred. Bioaccessibility of PAHs in food is the fraction of PAHs mobilized from food matrices during gastrointestinal digestion. An in vitro human digestion model was chosen for assessing the bioaccessibility of PAHs in food as it offers a simple, rapid, low cost alternative to human and animal studies; providing insights which may not be achievable in in vivo studies. Thus, this review aimed not only to provide an overview of general aspects of PAHs such as the formation, carcinogenicity, sources, occurrence, and factors affecting PAH concentrations, but also to enhance understanding of bioaccessibility assessment using an in vitro digestion model. PMID:26838201

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

    NASA Astrophysics Data System (ADS)

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

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

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

    PubMed

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

    2011-09-01

    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

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

    PubMed

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

    2006-12-01

    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

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

    PubMed

    Roscales, Jose L; Gonzlez-Sols, Jacob; Calabuig, Pascual; Jimnez, Begoa

    2011-10-01

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

  7. The Occurrence of 16 EPA PAHs in Food – A Review

    PubMed Central

    Zelinkova, Zuzana; Wenzl, Thomas

    2015-01-01

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

  8. Dry deposition of atmospheric polycyclic aromatic hydrocarbons (PAHs) in the southeast suburb of Beijing, China

    NASA Astrophysics Data System (ADS)

    Zhang, Shucai; Zhang, Wei; Shen, Yating; Wang, Kaiyan; Hu, Lianwu; Wang, Xuejun

    2008-07-01

    Dry deposition is an important path for pollutants entering soil and water. In this study, dustfall samples were collected at four representative sampling sites in the southeastern suburb of Beijing from March, 2005 to January, 2006, with a frequency of about once per month, and were analyzed for 16 USEPA priority PAHs using GC/MS. Results showed that the levels of ?16PAHs in dustfall samples were 0.72-40.45 g g - 1 . The levels of PHE and DahA were the highest and lowest among the 16 PAH compounds, with annual mean values of 2.07 g g - 1 and 0.009 g g - 1 , respectively. Two and three ring PAH compounds were the dominant ones in dustfall samples. The distribution patterns of PAH compounds in different rings in dustfall were different from those in TSP and gas phase. Annual average fluxes of dustfall and PAHs were 1 296.67 mg m - 2 d - 1 and 5.14 g m - 2 d - 1 , respectively. There were about 423 387.6 t dustfall and 1.7 t PAHs depositing onto the surface of Tongzhou District in 2005. Impacts of ground dust, meteorologic parameters, air pollution indexes and deposition velocities on PAHs deposition were discussed. Correlation analysis showed that the fluxes of 2-3 ring PAH compounds had significant positive correlation with the concentrations of 2-3 ring PAH compounds in TSP, and the fluxes of 4 ring PAH compounds had significant positive correlation with those in both TSP and gas phase, while no significant correlation existed between the fluxes of 5-6 ring PAH compounds and the concentrations of 5-6 ring PAH compounds in TSP or gas phase. A regression model was established to estimate the PAH fluxes.

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

    USGS Publications Warehouse

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

    2012-01-01

    Coal-tar-based pavement sealants, a major source of PAHs to urban water bodies, have recently been identified as a source of volatile PAHs to the atmosphere. We tracked the volatilization of PAHs for 1 year after application of a coal-tar-based pavement sealant by measuring gas-phase PAH concentrations above the pavement surface and solid-phase PAH concentrations in sealant scraped from the surface. Gas-phase concentrations at two heights (0.03 and 1.28 m) and wind speed were used to estimate volatilization flux. The sum of the concentrations of eight frequently detected PAHs (?PAH8) in the 0.03-m sample 1.6 h after application (297,000 ng m-3) was about 5000 times greater than that previously reported for the same height above unsealed parking lots (66 ng m-3). Flux at 1.6 h after application was estimated at 45,000 ?g m-2 h-1 and decreased rapidly during the 45 days after application to 160 ?g m-2 h-1. Loss of PAHs from the adhered sealant also was rapid, with about a 50% decrease in solid-phase ?PAH8 concentration over the 45 days after application. There was general agreement, given the uncertainties, in the estimated mass of ?PAH8 lost to the atmosphere on the basis of air sampling (23 g m-2) and adhered sealant sampling (6 g m-2) during the first 16 days after application, translating to a loss to the atmosphere of one-quarter to one-half of the PAHs in the sealcoat product. Combining the estimated mass of ?PAH8 released to the atmosphere with a national-use estimate of coal-tar-based sealant suggests that PAH emissions from new coal-tar-based sealcoat applications each year (~1000 Mg) are larger than annual vehicle emissions of PAHs for the United States.

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

    NASA Astrophysics Data System (ADS)

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

    2012-05-01

    Coal-tar-based pavement sealants, a major source of PAHs to urban water bodies, have recently been identified as a source of volatile PAHs to the atmosphere. We tracked the volatilization of PAHs for 1 year after application of a coal-tar-based pavement sealant by measuring gas-phase PAH concentrations above the pavement surface and solid-phase PAH concentrations in sealant scraped from the surface. Gas-phase concentrations at two heights (0.03 and 1.28 m) and wind speed were used to estimate volatilization flux. The sum of the concentrations of eight frequently detected PAHs (?PAH8) in the 0.03-m sample 1.6 h after application (297,000 ng m-3) was about 5000 times greater than that previously reported for the same height above unsealed parking lots (66 ng m-3). Flux at 1.6 h after application was estimated at 45,000 ?g m-2 h-1 and decreased rapidly during the 45 days after application to 160 ?g m-2 h-1. Loss of PAHs from the adhered sealant also was rapid, with about a 50% decrease in solid-phase ?PAH8 concentration over the 45 days after application. There was general agreement, given the uncertainties, in the estimated mass of ?PAH8 lost to the atmosphere on the basis of air sampling (2-3 g m-2) and adhered sealant sampling (6 g m-2) during the first 16 days after application, translating to a loss to the atmosphere of one-quarter to one-half of the PAHs in the sealcoat product. Combining the estimated mass of ?PAH8 released to the atmosphere with a national-use estimate of coal-tar-based sealant suggests that PAH emissions from new coal-tar-based sealcoat applications each year (1000 Mg) are larger than annual vehicle emissions of PAHs for the United States.

  11. Ca2+ Promoted the Low Transformation Efficiency of Plasmid DNA Exposed to PAH Contaminants

    PubMed Central

    Gao, Yanzheng; Long, Jian; Wang, Qian

    2013-01-01

    The effects of interactions between genetic materials and polycyclic aromatic hydrocarbons (PAHs) on gene expression in the extracellular environment remain to be elucidated and little information is currently available on the effect of ionic strength on the transformation of plasmid DNA exposed to PAHs. Phenanthrene and pyrene were used as representative PAHs to evaluate the transformation of plasmid DNA after PAH exposure and to determine the role of Ca2+ during the transformation. Plasmid DNA exposed to the test PAHs demonstrated low transformation efficiency. In the absence of PAHs, the transformation efficiency was 4.7 log units; however, the efficiency decreased to 3.72–3.14 log units with phenanthrene/pyrene exposures of 50 µg·L–1. The addition of Ca2+ enhanced the low transformation efficiency of DNA exposed to PAHs. Based on the co-sorption of Ca2+ and phenanthrene/pyrene by DNA, we employed Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and mass spectrometry (MS) to determine the mechanisms involved in PAH-induced DNA transformation. The observed low transformation efficiency of DNA exposed to either phenanthrene or pyrene can be attributed to a broken hydrogen bond in the double helix caused by planar PAHs. Added Ca2+ formed strong electrovalent bonds with “–POO––” groups in the DNA, weakening the interaction between PAHs and DNA based on weak molecular forces. This decreased the damage of PAHs to hydrogen bonds in double-stranded DNA by isolating DNA molecules from PAHs and consequently enhanced the transformation efficiency of DNA exposed to PAH contaminants. The findings provide insight into the effects of anthropogenic trace PAHs on DNA transfer in natural environments. PMID:23484001

  12. Ca2+ promoted the low transformation efficiency of plasmid DNA exposed to PAH contaminants.

    PubMed

    Kang, Fuxing; Wang, Hong; Gao, Yanzheng; Long, Jian; Wang, Qian

    2013-01-01

    The effects of interactions between genetic materials and polycyclic aromatic hydrocarbons (PAHs) on gene expression in the extracellular environment remain to be elucidated and little information is currently available on the effect of ionic strength on the transformation of plasmid DNA exposed to PAHs. Phenanthrene and pyrene were used as representative PAHs to evaluate the transformation of plasmid DNA after PAH exposure and to determine the role of Ca(2+) during the transformation. Plasmid DNA exposed to the test PAHs demonstrated low transformation efficiency. In the absence of PAHs, the transformation efficiency was 4.7 log units; however, the efficiency decreased to 3.72-3.14 log units with phenanthrene/pyrene exposures of 50 g L(-1). The addition of Ca(2+) enhanced the low transformation efficiency of DNA exposed to PAHs. Based on the co-sorption of Ca(2+) and phenanthrene/pyrene by DNA, we employed Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and mass spectrometry (MS) to determine the mechanisms involved in PAH-induced DNA transformation. The observed low transformation efficiency of DNA exposed to either phenanthrene or pyrene can be attributed to a broken hydrogen bond in the double helix caused by planar PAHs. Added Ca(2+) formed strong electrovalent bonds with "-POO(-)-" groups in the DNA, weakening the interaction between PAHs and DNA based on weak molecular forces. This decreased the damage of PAHs to hydrogen bonds in double-stranded DNA by isolating DNA molecules from PAHs and consequently enhanced the transformation efficiency of DNA exposed to PAH contaminants. The findings provide insight into the effects of anthropogenic trace PAHs on DNA transfer in natural environments. PMID:23484001

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

    PubMed

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

    2016-01-01

    Acute exposures to some individual polycyclic aromatic hydrocarbons (PAHs) and complex PAH mixtures are known to cause cardiac malformations and edema in the developing fish embryo. However, the heart is not the only organ impacted by developmental PAH exposure. The developing brain is also affected, resulting in lasting behavioral dysfunction. While acute exposures to some PAHs are teratogenically lethal in fish, little is known about the later life consequences of early life, lower dose subteratogenic PAH exposures. We sought to determine and characterize the long-term behavioral consequences of subteratogenic developmental PAH mixture exposure in both naive killifish and PAH-adapted killifish using sediment pore water derived from the Atlantic Wood Industries Superfund Site. Killifish offspring were embryonically treated with two low-level PAH mixture dilutions of Elizabeth River sediment extract (ERSE) (TPAH 5.04μg/L and 50.4μg/L) at 24h post fertilization. Following exposure, killifish were raised to larval, juvenile, and adult life stages and subjected to a series of behavioral tests including: a locomotor activity test (4days post-hatch), a sensorimotor response tap/habituation test (3months post hatch), and a novel tank diving and exploration test (3months post hatch). Killifish were also monitored for survival at 1, 2, and 5months over 5-month rearing period. Developmental PAH exposure caused short-term as well as persistent behavioral impairments in naive killifish. In contrast, the PAH-adapted killifish did not show behavioral alterations following PAH exposure. PAH mixture exposure caused increased mortality in reference killifish over time; yet, the PAH-adapted killifish, while demonstrating long-term rearing mortality, had no significant changes in mortality associated with ERSE exposure. This study demonstrated that early embryonic exposure to PAH-contaminated sediment pore water caused long-term locomotor and behavioral alterations in killifish, and that locomotor alterations could be observed in early larval stages. Additionally, our study highlights the resistance to behavioral alterations caused by low-level PAH mixture exposure in the adapted killifish population. Furthermore, this is the first longitudinal behavioral study to use killifish, an environmentally important estuarine teleost fish, and this testing framework can be used for future contaminant assessment. PMID:26548404

  14. Distribution of PAHs and the PAH-degrading bacteria in the deep-sea sediments of the high-latitude Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Dong, C.; Bai, X.; Sheng, H.; Jiao, L.; Zhou, H.; Shao, Z.

    2014-09-01

    Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants, which can be transferred to a long distance and tend to accumulation in marine sediment. However, PAHs distribution and natural bioattenuation is less known in open sea, especially in the Arctic Ocean. In this report, sediment samples were collected at four sites from the Chukchi Plateau to Makarov Basin in the summer of 2010. PAH composition and total concentrations were examined with GC-MS, we found that the concentrations of 16 EPA-priority PAHs varied from 2.0 to 41.6 ng g-1 dry weight in total and decreased with sediment depths and as well as from the southern to northern sites. Among the targeted PAHs, phenanthrene was relatively abundant in all sediments. To learn the diversity of bacteria involved in PAHs degradation in situ, the 16S rRNA gene of the total environmental DNA was analyzed with Illumina high throughput sequencing (IHTS). In all the sediments, occurred the potential degraders including Cycloclasticus, Pseudomonas, Halomonas, Pseudoalteromonas, Marinomonas, Bacillus, Dietzia, Colwellia, Acinetobacter, Alcanivorax, Salinisphaera and Shewanella, with Dietzia as the most abundant. Meanwhile on board, enrichment with PAHs was initiated and repeated transfer in laboratory to obtain the degrading consortia. Most above mentioned bacteria in addition to Hahella, Oleispira, Oceanobacter and Hyphomonas, occurred alternately as a predominant member in enrichment cultures from different sediments, as revealed with IHTS and PCR-DGGE. To reconfirm their role in PAH degradation, 40 different bacteria were isolated and characterized, among which Cycloclasticus and Pseudomonas showed the best degradation capability under low temperature. Taken together, PAHs and PAH-degrading bacteria were widespread in the deep-sea sediments of the Arctic Ocean. We propose that bacteria of Cycloclasticus, Pseudomonas, Pseudoalteromonas, Halomonas, Marinomonas and Dietzia may play the most important role in PAHs mineralization in situ.

  15. Distribution of PAHs and the PAH-degrading bacteria in the deep-sea sediments of the high-latitude Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Dong, C.; Bai, X.; Sheng, H.; Jiao, L.; Zhou, H.; Shao, Z.

    2015-04-01

    Polycyclic aromatic hydrocarbons (PAHs) are common organic pollutants that can be transferred long distances and tend to accumulate in marine sediments. However, less is known regarding the distribution of PAHs and their natural bioattenuation in the open sea, especially the Arctic Ocean. In this report, sediment samples were collected at four sites from the Chukchi Plateau to the Makarov Basin in the summer of 2010. PAH compositions and total concentrations were examined with GC-MS. The concentrations of 16 EPA-priority PAHs varied from 2.0 to 41.6 ng g-1 dry weight and decreased with sediment depth and movement from the southern to the northern sites. Among the targeted PAHs, phenanthrene was relatively abundant in all sediments. The 16S rRNA gene of the total environmental DNA was analyzed with Illumina high-throughput sequencing (IHTS) to determine the diversity of bacteria involved in PAH degradation in situ. The potential degraders including Cycloclasticus, Pseudomonas, Halomonas, Pseudoalteromonas, Marinomonas, Bacillus, Dietzia, Colwellia, Acinetobacter, Alcanivorax, Salinisphaera and Shewanella, with Dietzia as the most abundant, occurred in all sediment samples. Meanwhile, enrichment with PAHs was initiated onboard and transferred to the laboratory for further enrichment and to obtain the degrading consortia. Most of the abovementioned bacteria in addition to Hahella, Oleispira, Oceanobacter and Hyphomonas occurred alternately as predominant members in the enrichment cultures from different sediments based on IHTS and PCR-DGGE analysis. To reconfirm their role in PAH degradation, 40 different bacteria were isolated and characterized, among which Cycloclasticus Pseudomonas showed the best degradation capability under low temperatures. Taken together, PAHs and PAH-degrading bacteria were widespread in the deep-sea sediments of the Arctic Ocean. We propose that bacteria of Cycloclasticus, Pseudomonas, Pseudoalteromonas, Halomonas, Marinomonas and Dietzia may play the most important role in PAH mineralization in situ.

  16. Uptake of Pah's Onto Organic-coated Water Surfaces

    NASA Astrophysics Data System (ADS)

    Mmereki, B. T.; Donaldson, D. J.

    Previous laboratory and field studies have established the likelihood that aqueous par- ticles in the atmosphere can have a surface film composed of partially oxidized organic compounds, such as organic acids and alcohols. Such surface films could solvate hy- drophobic compounds at the droplet-atmosphere interface, altering the atmospheric lifetimes of the hydrophobic compounds, as well as potentially changing their oxida- tive pathways and photochemistry. We have developed a glancing-angle laser-induced fluorescence technique which provides good surface sensitivity towards PAHs at the water-air interface. Using this method, fluorescence spectra, adsorption isotherms and uptake from the gas phase to the surface have been measured for 3- and 4-ring PAHs on water surfaces coated with sub-monolayer films of hexanoic acid. Our initial results will be presented here.

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

    PubMed

    Bouchez, M; Blanchet, D; Bardin, V; Haeseler, F; Vandecasteele, J P

    1999-01-01

    The microbiological characteristics of the bacterial degradation of mixtures of five polycyclic aromatic hydrocarbons (PAH), phenanthrene, fluorene, anthracene, fluoranthene and pyrene, were investigated. Three pure bacterial strains using one or several of these PAH as carbon sources were selected. The interactions between PAH during the degradation of PAH pairs by each of these strains were studied and their effects on the kinetics and the balance of degradation were characterised. Competition between PAH and degradation by cometabolism were frequently observed. Mixed cultures of two or three strains, although possessing the global capacity to mineralise the set of five PAH, achieved limited degradation of the mixture. In contrast, a consortium from a PAH-contaminated soil readily mineralised the five-PAH mixture. The results suggested that soil consortia possessed a wider variety of strains capable to compensate for the competitive inhibition between PAH as well as specialised strains that mineralised potentially inhibitory PAH metabolites produced by cometabolism. PMID:11068829

  18. Prediction of PAH mutagenicity in human cells by QSAR classification.

    PubMed

    Papa, E; Pilutti, P; Gramatica, P

    2008-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants of high environmental concern. The experimental data of a mutagenicity test on human B-lymphoblastoid cells (alternative to the Ames bacterial test) for a set of 70 oxo-, nitro- and unsubstituted PAHs, detected in particulate matter (PM), were modelled by Quantitative Structure-Activity Relationships (QSAR) classification methods (k-NN, k-Nearest Neighbour, and CART, Classification and Regression Tree) based on different theoretical molecular descriptors selected by Genetic Algorithms. The best models were validated for predictivity both externally and internally. For external validation, Self Organizing Maps (SOM) were applied to split the original data set. The best models, developed on the training set alone, show good predictive performance also on the prediction set chemicals (sensitivity 69.2-87.1%, specificity 62.5-87.5%). The classification of PAHs according to their mutagenicity, based only on a few theoretical molecular descriptors, allows a preliminary assessment of the human health risk, and the prioritisation of these compounds. PMID:18311639

  19. Measurement of the recombination of photoproduced PAH ions

    NASA Astrophysics Data System (ADS)

    Novotny, O.; Sivaraman, B.; Rebrion-Rowe, C.; Travers, D.; Mitchell, J. B. A.; Rowe, B. R.

    2005-01-01

    A new technique, Flowing Afterglow with Photo Ions - FLAPI, has been developed for measuring the rate coefficient for the recombination of complex ions with electrons. The method is based on the FALP-MS apparatus at the Universit de Rennes I. A helium plasma is generated by a microwave discharge in a He buffer gas and downstream a small amount of argon gas is injected to get rid of helium metastables. A very small amount of neutral PAH molecules is added to the afterglow plasma by evaporation from a plate coated with the PAH to be studied. PAH ions are then produced by photoionization of the parent molecule using a pulsed UV laser (157 nm). The laser beam is oriented along the flow-tube and so a constant spatial concentration of photoions is obtained. The electron concentration along the flow-tube is measured by means of a movable Langmuir probe. The decay of the ion concentration in time is measured at a fixed position using a quadrupole mass spectrometer which is triggered by the laser pulse. Anthracene ion recombination has been studied using this technique and we have obtained the preliminary recombination rate coefficient (1.1 +/- 0.5) 10-6 cm3 s-1.

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

    PubMed

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

    2011-01-15

    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

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

    PubMed

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

    2015-04-01

    Mangrove sediment is unique in chemical and biological properties. Many of them suffer polycyclic aromatic hydrocarbon (PAH) contamination. However, the study on PAH biological remediation for mangrove sediment is deficient. Enriched PAH-degrading microbial consortium and electron acceptor amendment are considered as two effective measures. Compared to other electron acceptors, the study on CO2, which is used by methanogens, is still seldom. This study investigated the effect of NaHCO3 amendment on the anaerobic biodegradation of four mixed PAHs, namely fluorene (Fl), phenanthrene (Phe), fluoranthene (Flua) and pyrene (Pyr), with or without enriched PAH-degrading microbial consortium in mangrove sediment slurry. The trends of various parameters, including PAH concentrations, microbial population size, electron-transport system activities, electron acceptor and anaerobic gas production were monitored. The results revealed that the inoculation of enriched PAH-degrading consortium had a significant effect with half lives shortened by 7-13 days for 3-ring PAHs and 11-24 days for 4-ring PAHs. While NaHCO3 amendment did not have a significant effect on the biodegradation of PAHs and other parameters, except that CO2 gas in the headspace of experimental flasks was increased. One of the possible reasons is that mangrove sediment contains high concentrations of other electron acceptors which are easier to be utilized by anaerobic bacteria, the other one is that the anaerobes in mangrove sediment can produce enough CO2 gas even without adding NaHCO3. PMID:25872721

  2. Polycyclic Aromatic Acids Are Primary Metabolites of Alkyl-PAHs-A Case Study with Nereis diversicolor.

    PubMed

    Malmquist, Linus M V; Selck, Henriette; Jrgensen, Kre B; Christensen, Jan H

    2015-05-01

    Although concentrations of alkylated polycyclic aromatic hydrocarbons (alkyl-PAHs) in oil-contaminated sediments are higher than those of unsubstituted PAHs, only little attention has been given to metabolism and ecotoxicity of alkyl-PAHs. In this study we demonstrated that metabolism of alkyl-PAHs primarily forms polycyclic aromatic acids (PAAs). We generalize this to other alkyl-PAHs, based on literature and the present study of the metabolism of 1-methylphenanthrene, 3,6-dimethylphenanthrene, and 1-, 2-, 3-, and 6-methylchrysene related to their unsubstituted parent PAHs. Also, we observed that body burdens and production of PAAs was related to the position of the methyl group, showing the same isomer specific preferences as for microbial degradation of alkyl-PAHs. We detected a high production of PAAs, and larger metabolism of alkyl-PAHs than their unsubstituted parent PAHs. We therefore propose that carboxylic acid metabolites of alkyl-PAHs have the potential of constituting a new class of contaminants in marine waters that needs attention in relation to ecological risk assessments. PMID:25827176

  3. Polycyclic aromatic hydrocarbons (PAHs) in yerba mate (Ilex paraguariensis) from the Argentinean market.

    PubMed

    Garcia Londoo, Victor Alonso; Reynoso, Marcela; Resnik, Silvia

    2014-01-01

    Polycyclic aromatic hydrocarbons (PAHs) occurrence in 50 samples marketed in the main supermarkets from Argentina was surveyed. A high performance liquid chromatography (HPLC) method was applied with fluorescence detection (FLD) and UV-VIS diodes array detector (DAD) for the analysis of 16 PAHs in "yerba mate" (Ilex paraguariensis), with recoveries higher than 89% and limits of detection and quantification lower than that found by other methodologies in previous studies. Contamination expressed as the sum of 16 analysed PAHs ranged between 224.6 and 4449.5?gkg(-1) on dry mass. The contamination expressed as PAH4 (sum of benzo(a)pyrene, chrysene, benzo(a)anthracene and benzo(b)fluoranthene) varied between 8.3 and 512.4?gkg(-1). The correlation coefficient for PAH2 (sum of benzo(a)pyrene and chrysene) and PAH4 groups was 0.99, for PAH2 and PAH8 (sum of benzo(a)pyrene, chrysene, benzo(a)anthracene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(g,h,i)perylene, dibenzo(a,h)anthracene and indeno(1,2,3cd) pyrene) 0.97 and for PAH4 and PAH8 0.98. PMID:24867160

  4. Oral Bioavailability, Bioaccessibility, and Dermal Absorption of PAHs from Soil-State of the Science.

    PubMed

    Ruby, Michael V; Lowney, Yvette W; Bunge, Annette L; Roberts, Stephen M; Gomez-Eyles, Jose L; Ghosh, Upal; Kissel, John C; Tomlinson, Priscilla; Menzie, Charles

    2016-03-01

    This article reviews the state of the science regarding oral bioavailability, bioaccessibility, and dermal absorption of carcinogenic polycyclic aromatic hydrocarbons (cPAHs) in soil by humans, and discusses how chemical interactions may control the extent of absorption. Derived from natural and anthropomorphic origins, PAHs occur in a limited number of solid and fluid matrices (i.e., PAH sources) with defined physical characteristics and PAH compositions. Existing studies provide a strong basis for establishing that oral bioavailability of cPAHs from soil is less than from diet, and an assumption of 100% relative bioavailability likely overestimates exposure to cPAHs upon ingestion of PAH-contaminated soil. For both the oral bioavailability and dermal absorption studies, the aggregate data do not provide a broad understanding of how different PAH source materials, PAH concentrations, or soil chemistries influence the absorption of cPAHs from soil. This article summarizes the existing studies, identifies data gaps, and provides recommendations for the direction of future research to support new default or site-specific bioavailability adjustments for use in human health risk assessment. PMID:26824144

  5. The polynuclear aromatic hydrocarbon (PAH) content of herbage from a long-term grassland experiment

    NASA Astrophysics Data System (ADS)

    Wild, S. R.; Jones, K. C.; Johnston, A. E.

    Herbage samples harvested and stored from a long-term agricultural experiment started in the 1850s at Rothamsted Experimental Station (U.K.) have been analysed for polynuclear aromatic hydrocarbons (PAHs). The changing PAH content of samples since 1900 is thought to reflect broadly changes in the PAH content of air. Herbage concentrations ranged between 580 and 2750 μg ΣPAH kg -1 (total of 15 compounds). The lowest concentrations since 1900 were measured in the most recent samples (since the 1960s), with the highest between 1930 and 1955. Samples taken before 1956 contain statistically lower PAH contents than samples taken after this date, suggesting a reduction in PAH emissions from local and/or national sources. Samples taken between 1860 and 1900 contained much higher concentrations of ΣPAH (between 3620 and 6550 μg ΣPAH kg -1) and a different mixture of compounds. These samples may have been contaminated in the drying process after harvesting and prior to storage. The ΣPAH contents of these samples therefore probably do not reflect the atmospheric burden of PAHs at that time.

  6. Using in vitro bioaccessibility to refine estimates of human exposure to PAHs via incidental soil ingestion.

    PubMed

    Juhasz, Albert L; Tang, Wayne; Smith, Euan

    2016-02-01

    PAH bioaccessibility in contaminated soil was determined using the organic physiologically based extraction test with the inclusion of a sorption sink. Silicone cord was incorporated into the assay in order to overcome the limited capacity of the in vitro medium to accommodate desorbable PAHs. Initially, silicone cord sorption efficacy was determined by assessing sorption kinetics using PAH-spiked sand (phenanthrene, pyrene and benzo[a]pyrene; 10-1000mgkg(-1)). Irrespective of PAH and concentration, >95% of the initial PAH mass partitioned into the silicone cord within 12h although rates were lower at higher concentration and with increasing hydrophobicity. When PAH bioaccessibility was assessed in contaminated soil (n=18), contamination source (i.e. pyrogenic versus petrogenic) influenced PAH bioaccessibility. Individual PAH bioaccessibility ranged up to 81.72.7% although mean values ranged from 2.1 (acenaphthalene) to 20.8% (benzo[k]fluoranthene) with upper 95% confidence intervals of the means of 4.5 and 28.3% respectively. Although a PAH in vivo-in vitro correlation is yet to be established, bioaccessibility approaches incorporating sorption sinks represent a robust approach for estimating PAH bioavailability as the desorbable fraction may be a conservative measure of the absorbable fraction. PMID:26697808

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

    PubMed

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

    2010-07-01

    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

  8. Occurrence of aliphatic and polyaromatic hydrocarbons (PAHs) in Mytillus galloprovincialis from the traditional market in Marseille, France, by Gas Chromatography triplequadropole tandem Mass Spectrometry (GC-QQQ/MS)

    NASA Astrophysics Data System (ADS)

    Azis, M. Y.; Yelmiza; Asia, L.; Piram, A.; Bucharil, B.; Doumenq, P.; Syakti, A. D.

    2016-02-01

    Mediterranean mussel, Mytillusgalloprovincialis collected from the traditional market in Marseille, France,have been analysed using GC-QQQ/MS for their hydrocarbons (n-alkanes and polyaromatic hydrocarbons (PAHs)) extentwith two different solvent extraction, such as heptane:dichloromethane (HEP:DCM;1:1) and heptane:acetone (HEP:ACE; 1:1). The results showed hydrocarbons yielded from heptane:acetone extractionwere 28335 μg.kg- 1mussels dw (Ʃ n-alkanes C15-34) and 202 μg.kg-1mussels dw(ƩPAHs) while the yield from heptane:DCM extract was lower ca. 27026 μg.kg-1musselsdw and 133 μg.kg-1 mussels dw respectively from the Ʃn-alkanesC15-34and ƩPAHs. High hydrocarbon levels can be affected by the presence of lipids or other metabolites in mussels that have the same polarity with hydrocarbon compounds which has interferred the measurement. Several ratio parameter of n- alcanes and PAHs source in the mussels were evaluated to asses the origins of their hydrocarbons in mussels from which we suggested origins of hydrocarbons were pyrolytic and biogenic rather than petrogenic.

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

    PubMed

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

    2012-12-01

    In this study, the ranges of pollutants found in the soft tissues of Perna viridis collected from Kg. Masai and Kg. Sg. Melayu, both located in the Straits of Johore, were 0.85-1.58 μg/g dr