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Sample records for benzaanthracenes

  1. Persistence of benz(a)anthracene degradation products in an enclosed marine ecosystem

    SciTech Connect

    Hinga, K.R.; Pilson, M.E.Q.

    1987-07-01

    Carbon-14-labeled benz(a)anthracene was introduced into an enclosed marine ecosystem that had planktonic primary production and a heterotrophic benthos. Benz(a)anthracene, labeled CO/sub 2/, and operationally defined fractions of labeled degradation products were followed in water and sediments for 202 days. The major fraction of intermediate degradation products was sufficiently water soluble so as not to be readily extractable with organic solvents and at the end was still slowly decaying to CO/sub 2/. Both the parent benz(a)anthracene and degradation products found in the sediment appear to become protected from further alteration after about 2 months and may persist indefinitely. 41 references, 4 figures.

  2. Benz[a]anthracene Biotransformation and Production of Ring Fission Products by Sphingobium sp. Strain KK22

    PubMed Central

    Kunihiro, Marie; Ozeki, Yasuhiro; Nogi, Yuichi; Hamamura, Natsuko

    2013-01-01

    A soil bacterium, designated strain KK22, was isolated from a phenanthrene enrichment culture of a bacterial consortium that grew on diesel fuel, and it was found to biotransform the persistent environmental pollutant and high-molecular-weight polycyclic aromatic hydrocarbon (PAH) benz[a]anthracene. Nearly complete sequencing of the 16S rRNA gene of strain KK22 and phylogenetic analysis revealed that this organism is a new member of the genus Sphingobium. An 8-day time course study that consisted of whole-culture extractions followed by high-performance liquid chromatography (HPLC) analyses with fluorescence detection showed that 80 to 90% biodegradation of 2.5 mg liter−1 benz[a]anthracene had occurred. Biodegradation assays where benz[a]anthracene was supplied in crystalline form (100 mg liter−1) confirmed biodegradation and showed that strain KK22 cells precultured on glucose were equally capable of benz[a]anthracene biotransformation when precultured on glucose plus phenanthrene. Analyses of organic extracts from benz[a]anthracene biodegradation by liquid chromatography negative electrospray ionization tandem mass spectrometry [LC/ESI(−)-MS/MS] revealed 10 products, including two o-hydroxypolyaromatic acids and two hydroxy-naphthoic acids. 1-Hydroxy-2- and 2-hydroxy-3-naphthoic acids were unambiguously identified, and this indicated that oxidation of the benz[a]anthracene molecule occurred via both the linear kata and angular kata ends of the molecule. Other two- and single-aromatic-ring metabolites were also documented, including 3-(2-carboxyvinyl)naphthalene-2-carboxylic acid and salicylic acid, and the proposed pathways for benz[a]anthracene biotransformation by a bacterium were extended. PMID:23686261

  3. Toxicity of benz(a)anthracene and fluoranthene to marine phytoplankton in culture: does cell size really matter?

    PubMed

    Ben Othman, Hiba; Leboulanger, Christophe; Le Floc'h, Emilie; Mabrouk, Hassine Hadj; Hlaili, Asma Sakka

    2012-12-01

    The toxicity of benz(a)anthracene and fluoranthene (polycyclic aromatic hydrocarbons, PAHs) was evaluated on seven species of marine algae in culture belonging to pico-, nano-, and microphytoplankton, exposed to increasing concentrations of up to 2 mg L(-1). The short-term (24h) toxicity was assessed using chlorophyll a fluorescence transients, linked to photosynthetic parameters. The maximum quantum yield Fv/Fm was lower at the highest concentrations tested and the toxicity thresholds were species-dependent. For acute effects, fluoranthene was more toxic than benz(a)anthracene, with LOECs of 50.6 and 186 μg L(-1), respectively. After 72 h exposure, there was a dose-dependent decrease in cell density, fluoranthene being more toxic than benz(a)anthracene. The population endpoint at 72 h was affected to a greater extent than the photosynthetic endpoint at 24h. EC50 was evaluated using the Hill model, and species sensitivity was negatively correlated to cell biovolume. The largest species tested, the dinoflagellate Alexandrium catenella, was almost insensitive to either PAH. The population endpoint EC50s for fluoranthene varied from 54 μg L(-1) for the picophytoplankton Picochlorum sp. to 418 μg L(-1) for the larger diatom Chaetoceros muelleri. The size/sensitivity relationship is proposed as a useful model when there is a lack of ecotoxicological data on hazardous chemicals, especially in marine microorganisms. PMID:23122731

  4. Crystal induced phosphorescence from Benz(a)anthracene microcrystals at room temperature.

    PubMed

    Maity, Samir; Mazumdar, Prativa; Shyamal, Milan; Sahoo, Gobinda Prasad; Misra, Ajay

    2016-03-15

    Pure organic compounds that are also phosphorescent at room temperature are very rare in literature. Here, we report efficient phosphorescence emission from aggregated hydrosol of Benz(a)anthracene (BaA) at room temperature. Aggregated hydrosol of BaA has been synthesized by re-precipitation method and SDS is used as morphology directing agent. Morphology of the particles is characterized using optical and scanning electronic microcopy (SEM). Photophysical properties of the aggregated hydrosol are carried out using UV-vis, steady state and time resolved fluorescence study. The large stoke shifted structured emission from aggregated hydrosol of BaA has been explained due to phosphorescence emission of BaA at room temperature. In the crystalline state, the restricted intermolecular motions (RIM) such as rotations and vibrations are activated by crystal lattice. This rigidification effect makes the chromophore phosphorescent at room temperature. The possible stacking arrangement of the neighboring BaA within the aggregates has been substantiated by computing second order Fukui parameter as local reactivity descriptors. Computational study also reveals that the neighboring BaA molecules are present in parallel slipped conformation in its aggregated crystalline form. PMID:26720419

  5. Crystal induced phosphorescence from Benz(a)anthracene microcrystals at room temperature

    NASA Astrophysics Data System (ADS)

    Maity, Samir; Mazumdar, Prativa; Shyamal, Milan; Sahoo, Gobinda Prasad; Misra, Ajay

    2016-03-01

    Pure organic compounds that are also phosphorescent at room temperature are very rare in literature. Here, we report efficient phosphorescence emission from aggregated hydrosol of Benz(a)anthracene (BaA) at room temperature. Aggregated hydrosol of BaA has been synthesized by re-precipitation method and SDS is used as morphology directing agent. Morphology of the particles is characterized using optical and scanning electronic microcopy (SEM). Photophysical properties of the aggregated hydrosol are carried out using UV-vis, steady state and time resolved fluorescence study. The large stoke shifted structured emission from aggregated hydrosol of BaA has been explained due to phosphorescence emission of BaA at room temperature. In the crystalline state, the restricted intermolecular motions (RIM) such as rotations and vibrations are activated by crystal lattice. This rigidification effect makes the chromophore phosphorescent at room temperature. The possible stacking arrangement of the neighboring BaA within the aggregates has been substantiated by computing second order Fukui parameter as local reactivity descriptors. Computational study also reveals that the neighboring BaA molecules are present in parallel slipped conformation in its aggregated crystalline form.

  6. Mouse skin tumor-initiating activity of 5-, 7-, and 12-methyl- and fluorine-substituted benz(a)anthracenes

    SciTech Connect

    Wood, A.W.; Levin, W.; Chang, R.L.; Conney, A.H.; Slaga, T.J.; O'Malley, R.F.; Newman, M.S.; Buhler, D.R.; Jerina, D.M.

    1982-09-01

    Eleven methyl- and/or fluorine-substitued benz(a)anthracenes were evaluated for tumor-initating activity on mouse skin. Outbred CD-1 and outbred Sencar mice received a single topical application of the hydrocarbons followed by twice weekly application of the tumor promoter 12-O-tetradecanoylphorbol 13-acetate for 16-26 weeks. 7, 12-DMBA was almost two orders of magnitude more active as a tumor-initator than 7- and 12-methylbenz(a)anthracene. Methyl substitution at the 7- and 7,12-positions of benz(a)anthracence was significantly more effective in the enhancement of tumorigenic activity than fluorine substitution at these positions. Although 7-fluorobenz(a)anthracene, 12-fluorobenz(a)anthracene, and 7,12-difluorobenz(a)anthracene had only 0.15, 0.26, and less than 0.005 times the tumor-initiating activity of their respective methyl-substituted derivatives, they were severalfold more active than benz(a)anthracene. 7-Fluorobenz(a)anthracene was slightly less active than 12-fluorobenz(a)anthracene, whereas 7-methylbenz(a)anthracene was about twofold more active than 12-methylbenz(a)anthracene. For 7,12-disubstituted benz(a)anthracenes, 7-methyl-12-fluorobenz(a)anthracene was more than twice as tumorigenic as 7-fluoro-12-methylbenz(a)anthracene, but each was individually more active than 7-methylbenz(a)anthracene and 12-methylbenz(a)anthracene, respectively. Both fluorinated compounds were much less active than 7,12-DMBA. Substitution of fluorine or methyl at the 5-position of 7-methylbenz(a)anthracene and substition of fluorine at the 5-position of 12-methylbenz(a)anthracene dramatically reduced their tumorigenic activity.

  7. Oxidative DNA damage induced by benz[a]anthracene dihydrodiols in the presence of dihydrodiol dehydrogenase.

    PubMed

    Seike, Kazuharu; Murata, Mariko; Hirakawa, Kazutaka; Deyashiki, Yoshihiro; Kawanishi, Shosuke

    2004-11-01

    Tobacco smoke and polluted air are risk factors for lung cancer and contain many kinds of polycyclic aromatic hydrocarbons (PAHs) including benzo[a]pyrene (B[a]P) and benz[a]anthracene (BA). BA, as well as B[a]P, is assessed as probably carcinogenic to humans (IARC group 2A). BA is metabolized to several dihydrodiols. Dihydrodiol dehydrogenase (DD), a member of the aldo-keto reductase superfamily, catalyzes NAD(P)+-linked oxidation of dihydrodiols of aromatic hydrocarbons to corresponding catechols. To clarify the role of DD on PAH carcinogenesis, we examined oxidative DNA damage induced by trans-dihydrodiols of BA and B[a]P treated with DD using 32P-5'-end-labeled DNA fragments obtained from the human p53 tumor suppressor gene. In addition, we investigated the formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), an indicator of oxidative DNA damage, in calf thymus DNA by using HPLC with an electrochemical detector. DD-catalyzed BA-1,2-dihydrodiol caused Cu(II)-mediated DNA damage including 8-oxodG formation in the presence of NAD+. BA-1,2-dihydrodiol induced a Fpg sensitive and piperidine labile G lesion at the 5'-ACG-3' sequence complementary to codon 273 of the human p53 tumor suppressor gene, which is known as a hotspot. DNA damage was inhibited by catalase and bathocuproine, suggesting the involvement of H2O2 and Cu(I). The observation of NADH production by UV-visible spectroscopy suggested that DD catalyzed BA-1,2-dihydrodiol most efficiently to the corresponding catechol among the PAH-dihydrodiols tested. A time-of-flight mass spectroscopic study showed that the catechol form of BA-1,2-dihydrodiol formed after DD treatment. In conclusion, BA-1,2-dihydrodiol can induce DNA damage more efficiently than B[a]P-7,8-dihydrodiol and other BA-dihydrodiols in the presence of DD. The reaction mechanism on oxidative DNA damage may be explained by theoretical calculations with an enthalpy change of dihydrodiols and oxidation potential of their catechol forms. DD

  8. Benz[a]anthracene

    Integrated Risk Information System (IRIS)

    Benz [ a ] anthracene ; CASRN 56 - 55 - 3 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinoge

  9. The anharmonic quartic force field infrared spectra of five non-linear polycyclic aromatic hydrocarbons: Benz[a]anthracene, chrysene, phenanthrene, pyrene, and triphenylene.

    PubMed

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

    2016-08-28

    The study of interstellar polycyclic aromatic hydrocarbons (PAHs) relies heavily on theoretically predicted infrared spectra. Most earlier studies use scaled harmonic frequencies for band positions and the double harmonic approximation for intensities. However, recent high-resolution gas-phase experimental spectroscopic studies have shown that the harmonic approximation is not sufficient to reproduce experimental results. In our previous work, we presented the anharmonic theoretical spectra of three linear PAHs, showing the importance of including anharmonicities into the theoretical calculations. In this paper, we continue this work by extending the study to include five non-linear PAHs (benz[a]anthracene, chrysene, phenanthrene, pyrene, and triphenylene), thereby allowing us to make a full assessment of how edge structure, symmetry, and size influence the effects of anharmonicities. The theoretical anharmonic spectra are compared to spectra obtained under matrix isolation low-temperature conditions, low-resolution, high-temperature gas-phase conditions, and high-resolution, low-temperature gas-phase conditions. Overall, excellent agreement is observed between the theoretical and experimental spectra although the experimental spectra show subtle but significant differences. PMID:27586928

  10. Influence of mode of exposure and the presence of a tubiculous polychaete on the fate of benz(a)anthracene in the benthos

    SciTech Connect

    McElroy, A.E.; Farrington, J.W.; Teal, J.M. )

    1990-11-01

    The distribution and metabolism of ({sup 14}C-12)benz(a)-anthracene (BA) was followed in benthic microcosms in the presence and absence of the polychaete Nereis virens for periods of 4-25 days to simultaneously assess the effects of mode of introduction and the presence of large burrowing organisms on the fate of polycyclic aromatic hydrocarbons (PAH) and their metabolites in the benthos. Radiolabeled BA was added to the chambers in three ways: already sorbed to the entire sediment reservoir, directly into the water column, or incorporated into food for the worms. BA added to the water column was more available for uptake and metabolism by worms and microbial mineralization to CO{sub 2} than BA previously sorbed to the entire sediment reservoir. In experiments with the sediment reservoir uniformly labeled with BA, worms increased flux of BA from the sediment, and with time, their presence led to increased rates of microbial mineralization of BA to CO{sub 2}. Dietary BA was most rapidly metabolized by Nereis.

  11. Environmental concentrations of benz[a]anthracene induce developmental defects and DNA damage and impair photomotor response in Japanese medaka larvae.

    PubMed

    Le Bihanic, Florane; Sommard, Vivien; Perrine, de Lansalut; Pichon, Anaïk; Grasset, Julie; Berrada, Saadia; Budzinski, Hélène; Cousin, Xavier; Morin, Bénédicte; Cachot, Jérôme

    2015-03-01

    Benz[a]anthracene (BaA) is a ubiquitous polycyclic aromatic hydrocarbon found in numerous aquatic ecosystems. However, ecotoxicological data in aquatic organisms are scarce. To remedy this lack of data, Japanese medaka (Oryzias latipes) embryos were exposed to BaA and toxic effects were investigated at multiple toxicological endpoints. Japanese medaka embryos were incubated onto BaA-spiked artificial sediment for 9 days at low or moderate environmental concentrations ranging from 0.9 to 12 µgg(-1) dw. BaA-exposed embryos exhibited significant tachycardia. BaA exposure was also shown to increase CYP1A activity in the hepato-biliary tissue as well as craniofacial deformities and DNA damage in pro-larvae. The photomotor response of BaA-exposed larvae was reduced in comparison to the control group. According to this set of tests, the lowest tested and observed effect concentration (LOEC) for Japanese medaka early life stages was equivalent to 0.92 µgg(-1) dw of BaA. This concentration fall into the range of concentrations frequently encountered in sediments of polluted aquatic ecosystems. Taking into consideration these results, BaA represents a threat for fish early life stages in particular those developing onto or into contaminated sediments. PMID:25528488

  12. Degradation of pyrene, benz[a]anthracene, and benzo[a]pyrene by Mycobacterium sp. strain RJGII-135, isolated from a former coal gasification site.

    PubMed

    Schneider, J; Grosser, R; Jayasimhulu, K; Xue, W; Warshawsky, D

    1996-01-01

    The degradation of three polycyclic aromatic hydrocarbons (PAH), pyrene (PYR), benz[a]anthracene (BAA), and benzo[a]pyrene (BaP), by Mycobacterium sp. strain RJGII-135 was studied. The bacterium was isolated from an abandoned coal gasification site soil by analog enrichment techniques and found to mineralize [14C]PYR. Further degradation studies with PYR showed three metabolites formed by Mycobacterium sp. strain RJGII-135, including 4,5-phenanthrene-dicarboxylic acid not previously isolated, 4-phenanthrene-carboxylic acid, and 4,5-pyrene-dihydrodiol. At least two dihydrodiols, 5,6-BAA-dihydrodiol and 10,11-BAA-dihydrodiol, were confirmed by high-resolution mass spectral and fluorescence analyses as products of the biodegradation of BAA by Mycobacterium sp. strain RJGII-135. Additionally, a cleavage product of BAA was also isolated. Mass spectra and fluorescence data support two different routes for the degradation of BaP by Mycobacterium sp. strain RJGII-135. The 7,8-BaP-dihydrodiol and three cleavage products of BaP, including 4,5-chrysene-dicarboxylic acid and a dihydro-pyrene-carboxylic acid metabolite, have been isolated and identified as degradation products formed by Mycobacterium sp. strain RJGII-135. These latter results represent the first example of the isolation of BaP ring fission products formed by a bacterial isolate. We propose that while this bacterium appears to attack only one site of the PYR molecule, it is capable of degrading different sites of the BAA and BaP molecules, and although the sites of attack may be different, the ability of this bacterium to degrade these PAH is well supported. The proposed pathways for biodegradation of these compounds by this Mycobacterium sp. strain RJGII-135 support the dioxygenase enzymatic processes reported previously for other bacteria. Microorganisms like Mycobacterium sp. strain RJGII-135 will be invaluable in attaining the goal of remediation of sites containing mixtures of these PAH. PMID:8572690

  13. ANALYSIS OF CYCLOPENTAFUSED ISOMERS OF BENZ(A)ANTHRACENE IN WOOD SMOKE (JOURNAL VERSION)

    EPA Science Inventory

    A previously-unidentified peak occurring in chromatograms of the polycyclic aromatic hydrocarbon fraction from wood smoke particulate extracts analyzed by capillary gas chromatography on a DB-5 column was found to correspond in retention index and molecular mass either to benzo(a...

  14. Effects of methyl substitutions on benz[a]anthracene derivatives-induced immunosuppression

    SciTech Connect

    Saas, P.; Bohuon, C.; Pallardy, M.

    1996-11-01

    Polycyclic aromatic-hydrocarbons are ubiquitous environmental contaminants known to be carcinogenic as well as immunosuppressive. Structure-activity studies have demonstrated that modifications in the number of methyl groups of benzanthracenic compounds lead to major changes in their biological activities such as induction of tumors. In the present study, we investigated the immunosuppressive effects of three benzanthracene derivatives differing by number or position of methyl radicals. 7,12-Dimethylbenz[a]anthracene, 12-methylbenz[a]anthracene, and 7-methylbenz[a]anthracene were tested for their ability to inhibit T-cell proliferation. For this purpose, we employed an in vitro activation model utilizing concanavalin A (ConA) or anti-CD3 monoclonal antibody (anti-CD3 mAb) to induce proliferation of murine T-lymphocytes form B6C3F1 mice. The three compounds inhibited splenocyte proliferation stimulated with anti-CD3 mAb, whereas DMBA and 12-MBA, but not 7-MBA, inhibited ConA-induced lymphoproliferation. Results concerning parameters involving interleukin-2 (IL-2) were correlated with those obtained for lymphoproliferation. IL-2 production and number of IL-2 receptors (IL-2R) per cell were inhibited by the three molecules tested, except for IL-2 production following ConA activation cells treated with 7-MBA. Only DMBA profoundly affected IL-2 responsiveness, suggesting that this compound may inhibit both G0 to G1 and G1 to S transitions of the cell cycle. Addition of exogenous cytokines such as IL-1 and IL-6 with IL-2, or L-2 alone, suggested that, for the three compounds tested, IL-1 and IL-6 production are not involved in benz[a]anthracene-induced immunosuppression. These results demonstrate that methylation at both 7 and 12 positions of the benzanthracene ring significantly enhances immunosuppression. DMBA may act on signal transduction mediated by the T-cell receptor (TCR) and the IL-2R, while this is not the case for 7-MBA and 12-MBA. 32 refs., 5 figs., 1 tab.

  15. CYCLOPENTA-FUSED ISOMERS OF BENZ(A)ANTHRACENE II: MUTAGENIC EFFECTS ON MAMMALIAN CELLS

    EPA Science Inventory

    Cyclopenta-fused polycyclic aromatic hydrocarbons (PAH) are a unique class of PAH found in the environment. Acenaphthylene, acephenanthrylene and cyclopenta (cd) pyrene represent characterized cyclopenta-PAH already identified as air pollutants. The pyrolytic synthesis of PAH fro...

  16. Some bioaccumulation factors and biota-sediment accumulation factors for polycyclic aromatic hydrocarbons in Lake Trout

    SciTech Connect

    Burkhard, L.P.; Lukasewycz, M.T.

    2000-05-01

    Bioaccumulation factors (BAFs) and biota-sediment accumulation factors (BSAFs) for phenanthrene, fluoranthene, pyrene, benz[a]anthracene, and chrysene/triphenylene were calculated using the tissue data of Zabik et al. for Salvelinus namaycush siscowet with a 20.5% lipid content, the water data of Baker and Eisenreich, and the sediment data of Baker and Eisenreich for the Lake Superior ecosystem. Log BAFs, both lipid normalized and based on the freely dissolved concentration of the chemical in the water, of 1.95, 3.22, 4.72, 4.73, and 3.61 were calculated for phenanthrene, fluoranthene, pyrene, benz[a]anthracene, and chrysene/triphenylene, respectively. The BSAFs for phenanthrene, fluoranthene, pyrene, benz[a]anthracene, and chrysene/tripenylene were 0.00011, 0.00016, 0.0071, 0.0054, and 0.00033, respectively.

  17. THE EFFECT OF ROUTE OF ADMINISTRATION OF POLYCYCLIC AROMATIC HYDROCARBONS ON DNA ADDUCTION AND CYTOGENETIC DAMAGE IN PERIPHERAL BLOOD LYMPHOCYTES OF MICE AND RATS

    EPA Science Inventory

    Experiments were designed to investigate how the route of exposure to polycyclic aromatic hydrocarbons (PAHs) in mice and rats affects the induction of cytogenetic endpoints and DNA adduction. Both mice and rats were exposed to 100 mg/kg of benz[a]anthracene (B[a]A), benzo[b]fl...

  18. COMPARATIVE ANALYSIS OF THE ELECTROSTATIC POTENTIALS OF SOME STRUCTURAL ANALOGUES OF 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN AND OF RELATED AROMATIC SYSTEMS

    EPA Science Inventory

    We have carried out an ab initio STO-5G computational analysis of the electrostatic potential of four structural analogues of the highly toxic 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and four related aromatic systems: benzo[a]pyrene, benz[a]anthracene and two isomeric benzofla...

  19. Reference range levels of polycyclic aromatic hydrocarbons in the US population by measurement of urinary monohydroxy metabolites

    SciTech Connect

    Grainger, James . E-mail: jag2@cdc.gov; Huang, Wenlin; Patterson, Donald G.; Turner, Wayman E.; Pirkle, James; Caudill, Samuel P.; Wang, Richard Y.; Needham, Larry L.; Sampson, Eric J.

    2006-03-15

    We developed a gas chromatography isotope-dilution high-resolution mass spectrometry (GC/Id-HRMS) method for measuring 14 polycyclic aromatic hydrocarbon (PAH) metabolites representing seven parent PAHs in 3 mL of urine at low parts-per-trillion levels. PAH levels were determined in urine samples collected in 1999 and 2000 from approximately 2400 participants in the National Health and Nutrition Examination Survey, and, for the first time, reference range values were calculated for these metabolites in the US population. Using this GC/ID-HRMS method, we found detectable concentrations for monohydroxy metabolite isomers of fluorene, phenanthrene, fluoranthene, pyrene, and chrysene, benzo[c]phenanthrene, and benz[a]anthracene. Some monohydroxy metabolite isomers of benzo[c]phenanthrene, chrysene, and benz[a]anthracene exhibited low detection frequencies that did not allow for geometric mean calculations. Our study results enabled us to establish a reference range for the targeted PAHs in the general US population.

  20. Baeyer-Villiger C-C bond cleavage reaction in gilvocarcin and jadomycin biosynthesis

    PubMed Central

    Tibrewal, Nidhi; Pahari, Pallab; Wang, Guojun; Kharel, Madan K.; Morris, Caleb; Downey, Theresa; Hou, Yanpeng; Bugni, Tim S.; Rohr, Jürgen

    2012-01-01

    GilOII has been unambiguously identified as the key enzyme performing the crucial C-C bond cleavage reaction responsible for the unique rearrangement of a benz[a]anthracene skeleton to the benzo[d]naphthopyranone backbone typical for the gilvocarcin type natural anticancer antibiotics. Further investigations of this enzyme led to the isolation of a hydroxy-oxepinone intermediate which allowed important conclusions regarding the cleavage mechanism. PMID:23102024

  1. Influence of route of entry on toxicity of polycyclic aromatic hydrocarbons to the cricket (Acheta domesticus)

    SciTech Connect

    Walton, B.T.

    1980-01-01

    In the present study, acute and chronic toxicities of five PAHs (naphthalene, anthracene, benz(a)anthracene, pyrene, and benzo(a)pyrene) and an oxygenated PAH derivative (anthrone) were determined in a terrestrial insect, Acheta domesticus (L.), with emphasis on the influence of route of entry on toxicity. Hexamethylphosphoric triamide (hempa) was included in the chronic tests since this chemosterilant is a useful reference compound for investigations of reproductive effects of chemicals in insects.

  2. Salicylate stimulates the degradation of high-molecular weight polycyclic aromatic hydrocarbons by Pseudomonas saccharophila P15

    SciTech Connect

    Chen, S.H.; Aitken, M.D.

    1999-02-01

    Pseudomonas saccharophila P15 was isolated from soil contaminated with polycyclic aromatic hydrocarbons (PAH) and previously was reported to degrade a variety of low- and high-molecular weight PAH. Strain P15 grows on phenanthrene by a known pathway in which salicylate is an intermediate. Preincubation with phenanthrene and downstream intermediates through salicylate stimulated PAH dioxygenase activity and initial rates of phenanthrene removal, suggesting that salicylate is the inducer of these activities. Salicylate also greatly enhanced initial rates of removal of fluoranthene, pyrene, benz[a]anthracene, chrysene, and benzo[a]pyrene, high-molecular weight substrates that strain P15 does not use for growth.The specific rate of removal of benzo[a]pyrene was at least 2 orders of magnitude lower than that of the four-ring compounds and nearly 5 orders of magnitude lower than that of phenanthrene. The mineralization of phenanthrene, benz[a]anthracene, chrysene, and benzo[a]pyrene was stimulated by preincubation with phenanthrene or salicylate, although significant mineralization of phenanthrene, benz[a]anthracene, and chrysene occurred in uninduced cultures. Further experiments with chrysene indicated that chrysene does not appear to induce its own mineralization. The results suggest that P. saccharophila P15 expresses a low level of constitutive PAH metabolism which is inducible to much higher levels and that high-molecular weight PAH metabolism by this organism is induced by the low-molecular weight substrate phenanthrene and by salicylate.

  3. Stable-isotope probing of the polycyclic aromatic hydrocarbon-degrading bacterial guild in a contaminated soil

    PubMed Central

    Jones, Maiysha D.; Crandell, Douglas W.; Singleton, David R.; Aitken, Michael D.

    2016-01-01

    The bacteria responsible for the degradation of naphthalene, phenanthrene, pyrene, fluoranthene, or benz[a]anthracene in a polycyclic aromatic hydrocarbon (PAH)-contaminated soil were investigated by DNA-based stable-isotope probing (SIP). Clone libraries of 16S rRNA genes were generated from the 13C-enriched (“heavy”) DNA recovered from each SIP experiment, and quantitative PCR primers targeting the 16S rRNA gene were developed to measure the abundances of many of the SIP-identified sequences. Clone libraries from the SIP experiments with naphthalene, phenanthrene, and fluoranthene primarily contained sequences related to bacteria previously associated with the degradation of those compounds. However, Pigmentiphaga-related sequences were newly associated with naphthalene and phenanthrene degradation, and sequences from a group of uncultivated γ-Proteobacteria known as Pyrene Group 2 were newly associated with fluoranthene and benz[a]anthracene degradation. Pyrene Group 2-related sequences were the only sequences recovered from the clone library generated from SIP with pyrene, and they were 82% of the sequences recovered from the clone library generated from SIP with benz[a]anthracene. In time-course experiments with each substrate in unlabeled form, the abundance of each of the measured groups increased in response to the corresponding substrate. These results provide a comprehensive description of the microbial ecology of a PAH-contaminated soil as it relates to the biodegradation of PAHs from two to four rings, and they underscore that bacteria in Pyrene Group 2 are well-suited for the degradation of four-ring PAHs. PMID:21564459

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

    PubMed Central

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

    2015-01-01

    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 µM of benz[a]anthracene (BAA) or benz[a]anthracene-7, 12-dione (BAQ). By integrating multivariate, univariate and pathway analyses, a total of 62 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

  5. 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 µM 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

  6. Continuous surface seawater surveillance on poly aromatic hydrocarbons (PAHs) and mutagenicity of East and South China Seas

    NASA Astrophysics Data System (ADS)

    Ren, Huifeng; Kawagoe, Tsubasa; Jia, Huijuan; Endo, Hideaki; Kitazawa, Akira; Goto, Sumio; Hayashi, Tetsuhito

    2010-02-01

    Poly aromatic hydrocarbons (PAHs) and mutagenic compounds were adsorbed on Blue Rayon (BR) to monitor the pollution level of the surface seawater of the East and South China Seas by continuous sampling of seawater along the ship lane of our research and training vessel Umitaka-Maru. Eluted PAHs from BR were quantitatively determined by HPLC and their total amount in each sample ranged between 30.40 and 120.29 ng per liter of seawater, showing a difference of about 4 times among 8 samples. Acenaphthylene, naphthalene, and benz(a)anthracene were the most common PAHs found in the East and South China Seas, however, no big difference was observed in the concentrations of PAHs distributed throughout those two closed seas. Mutagenicity was detected as pseudo-positive from three samples. Among them, one sample collected along the east edge of the East China Sea showed a strong direct cytotoxicity which interrupted the mutagenicity test.

  7. 40 CFR Appendix V to Part 266 - Risk Specific Doses (10−5)

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    .... Unit risk (m3/μg) RsD (μg/m3) Acrylamide 79-06-1 1.3E−03 7.7E−03 Acrylonitrile 107-13-1 6.8E−05 1.5E−01 Aldrin 309-00-2 4.9E−03 2.0E−03 Aniline 62-53-3 7.4E−06 1.4E+00 Arsenic 7440-38-2 4.3E−03 2.3E−03 Benz(a)anthracene 56-55-3 8.9E−04 1.1E−02 Benzene 71-43-2 8.3E−06 1.2E+00 Benzidine 92-87-5 6.7E−02 1.5E−04...

  8. 40 CFR Appendix V to Part 266 - Risk Specific Doses (10−5)

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    .... Unit risk (m3/μg) RsD (μg/m3) Acrylamide 79-06-1 1.3E−03 7.7E−03 Acrylonitrile 107-13-1 6.8E−05 1.5E−01 Aldrin 309-00-2 4.9E−03 2.0E−03 Aniline 62-53-3 7.4E−06 1.4E+00 Arsenic 7440-38-2 4.3E−03 2.3E−03 Benz(a)anthracene 56-55-3 8.9E−04 1.1E−02 Benzene 71-43-2 8.3E−06 1.2E+00 Benzidine 92-87-5 6.7E−02 1.5E−04...

  9. 40 CFR Appendix V to Part 266 - Risk Specific Doses (10−5)

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    .... Unit risk (m3/μg) RsD (μg/m3) Acrylamide 79-06-1 1.3E−03 7.7E−03 Acrylonitrile 107-13-1 6.8E−05 1.5E−01 Aldrin 309-00-2 4.9E−03 2.0E−03 Aniline 62-53-3 7.4E−06 1.4E+00 Arsenic 7440-38-2 4.3E−03 2.3E−03 Benz(a)anthracene 56-55-3 8.9E−04 1.1E−02 Benzene 71-43-2 8.3E−06 1.2E+00 Benzidine 92-87-5 6.7E−02 1.5E−04...

  10. 40 CFR Appendix V to Part 266 - Risk Specific Doses (10−5)

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    .... Unit risk (m3/μg) RsD (μg/m3) Acrylamide 79-06-1 1.3E−03 7.7E−03 Acrylonitrile 107-13-1 6.8E−05 1.5E−01 Aldrin 309-00-2 4.9E−03 2.0E−03 Aniline 62-53-3 7.4E−06 1.4E+00 Arsenic 7440-38-2 4.3E−03 2.3E−03 Benz(a)anthracene 56-55-3 8.9E−04 1.1E−02 Benzene 71-43-2 8.3E−06 1.2E+00 Benzidine 92-87-5 6.7E−02 1.5E−04...

  11. 40 CFR Appendix V to Part 266 - Risk Specific Doses (10−5)

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    .... Unit risk (m3/μg) RsD (μg/m3) Acrylamide 79-06-1 1.3E−03 7.7E−03 Acrylonitrile 107-13-1 6.8E−05 1.5E−01 Aldrin 309-00-2 4.9E−03 2.0E−03 Aniline 62-53-3 7.4E−06 1.4E+00 Arsenic 7440-38-2 4.3E−03 2.3E−03 Benz(a)anthracene 56-55-3 8.9E−04 1.1E−02 Benzene 71-43-2 8.3E−06 1.2E+00 Benzidine 92-87-5 6.7E−02 1.5E−04...

  12. Strategies for synthesis of adducts of omicron-quinone metabolites of carcinogenic polycyclic aromatic hydrocarbons with 2'-deoxyribonucleosides.

    PubMed

    Ran, Chongzhao; Dai, Qing; Ruan, Qian; Penning, Trevor M; Blair, Ian A; Harvey, Ronald G

    2008-02-01

    Polycyclic aromatic hydrocarbons (PAHs) are major environmental carcinogens produced in the combustion of fossil fuels, tobacco, and other organic matter. Current evidence indicates that PAHs are transformed enzymatically to active metabolites that react with DNA to form adducts that result in mutations. Three activation pathways have been proposed: the diol epoxide path, the radical-cation path, and the quinone path. The latter involves aldo-keto reductase mediated oxidation of PAH dihydrodiol metabolites to catechols that enter into redox cycles with quinones. This results in generation of reactive oxygen species (ROS) that attack DNA, and the PAH quinones also react with DNA to form adducts. Several strategies for synthesis of the stable adducts formed by the o-quinone metabolites of carcinogenic PAHs with 2'-deoxyribonucleosides were investigated and compared. The PAH quinones studied were benz[a]anthracene-3,4-dione and its 7-methyl- and 7,12-dimethyl- derivatives. The parent PAHs represent a range of carcinogenicity from inactive to highly potent. Two synthetic methods were devised that differ in the catalyst employed, Pd(OAc)(2) or CuI. The Pd-mediated method involved coupling a protected amino-catechol PAH derivative with a halo-2'-deoxyribonucleoside. The copper-mediated method entailed reaction of a halo-PAH catechol derivative with a 2'-deoxyribonucleoside. Adducts of benz[a]anthracene-3,4-dione (and its 7-methyl- and 7,12-dimethyl- derivatives) with 2'-deoxyadenosine and 2'-deoxyguanosine were prepared by these methods. Availability of adducts of these types through synthesis makes possible for the first time biological studies to determine the role of these adducts in tumorigenesis. The copper-mediated method offers advantages of economy, adaptability to large-scale preparation, utility for synthesis of (13)C- or (15)N-labeled analogues, and nonformation of bis-adducts as secondary products. PMID:18181642

  13. Polycyclic aromatic hydrocarbon levels in European catfish from the upper Po River basin.

    PubMed

    Squadrone, Stefania; Favaro, Livio; Abete, Maria Cesarina; Vivaldi, Barbara; Prearo, Marino

    2014-04-01

    Polycyclic aromatic hydrocarbons (PAHs) are a major concern in environmental studies as many of them have been labeled as probable carcinogens by the International Agency for Research on Cancer (IARC 1983). Due to their lipophilic properties and resistance to degradation, PAHs can accumulate in organic tissue. As a consequence, alarming concentrations of these compounds have been found in many aquatic species. The European catfish (Silurus glanis) is a top food chain predator that is considered to be a reliable bio-indicator of environmental pollution. From 2009 to 2011, 54 specimens of S. glanis were captured from four different sites covering the area of the Po River basin (Northern Italy). Fish muscles were analyzed in the laboratory to determine the levels of nine PAHs, namely naphthalene, acenaphthene, fluorene, phenanthrene, anthracene, pyrene, benz[a]anthracene, chrysene, and benz[a]pyrene (BaP), which were detected by high-performance liquid chromatography (HPLC). The total average concentration of PAHs was 26.90 ± 49.50 ng g(-1) (min 0.60, max 275.75 ng g(-1)). Analysis showed that 9.20% of the fish muscles exceeded the maximum levels of 2 ng g(-1) set for BaP by European regulations (Commission Regulation (EC), 2006). Values measured for benz[a]pyrene ranged from 0.05 to 8.20 ng g(-1) (mean 1.07 ± 1.58 ng g(-1)). Chrysene and benz[a]anthracene, both considered potential human carcinogens (PAH2), were found at levels of 4.40 and 0.05 ng g(-1) (mean values), respectively. The highest mean concentration was recorded for anthracene (12.92 ng g(-1)), which has been recently included in the list of substances of very high concern (SVHC) as reported by the European Chemicals Agency (ECHA 1-9, 2009). PMID:24306443

  14. Long-term toxicity of five polycyclic aromatic hydrocarbons for the terrestrial isopods Oniscus asellus and Porcellio scaber

    SciTech Connect

    Brummelen, T.C. van; Gestel, C.A.M. van; Verweij, R.A.

    1996-07-01

    Polycyclic aromatic hydrocarbons (PAHs) are a common component of soil pollution, yet little is known of the ecotoxicological risks these compounds may pose to life in soil. This article reports the ecotoxicity of five PAHs for two terrestrial isopod species. Isopods were exposed to food contaminated with four different concentrations of either fluorene, phenanthrene, fluoranthene (up to 4 {micro}mol/g), benz[a]anthracene, or benzo[a]pyrene (up to 1.25 {micro}mol/.g). Exposure of Porcellio scaber lasted 16 weeks, and no adverse effects on survival, growth, or total protein (only females tested) were observed in any of the treatments. A small but significant reduction in growth of Oniscus asellus was observed at 47 weeks of exposure to 0.125 {micro}mol benz[a]anthracene-g{sup {minus}1} dry weight and higher concentrations. A significant stimulation of the reproduction of O. asellus was observed in some of the phenanthrene, fluoranthene, benz[a]anthracene, and benzo[a]pyrene treatments; a larger proportion of the females were gravid, which resulted in a higher number of juveniles per female. Exposure did not significantly affect brood size, weight of the mother after release of the juveniles, or the survival of the juveniles upon starvation. Total protein content of females was significantly reduced at 0.4 {micro}mol fluorene g{sup {minus}1} dry weight and higher concentrations. Growth and protein content of isopods is likely to be affected by PAH exposure only at highly contaminated sites. The ecological consequences of stimulated reproduction and possible DNA damage are poorly understood and require further attention because soil invertebrates may be exposed to PAHs over many generations.

  15. Characterization of a naphthalene dioxygenase endowed with an exceptionally broad substrate specificity toward polycyclic aromatic hydrocarbons.

    PubMed

    Jouanneau, Yves; Meyer, Christine; Jakoncic, Jean; Stojanoff, Vivian; Gaillard, Jacques

    2006-10-10

    In Sphingomonas CHY-1, a single ring-hydroxylating dioxygenase is responsible for the initial attack of a range of polycyclic aromatic hydrocarbons (PAHs) composed of up to five rings. The components of this enzyme were separately purified and characterized. The oxygenase component (ht-PhnI) was shown to contain one Rieske-type [2Fe-2S] cluster and one mononuclear Fe center per alpha subunit, based on EPR measurements and iron assay. Steady-state kinetic measurements revealed that the enzyme had a relatively low apparent Michaelis constant for naphthalene (K(m) = 0.92 +/- 0.15 microM) and an apparent specificity constant of 2.0 +/- 0.3 mM(-)(1) s(-)(1). Naphthalene was converted to the corresponding 1,2-dihydrodiol with stoichiometric oxidation of NADH. On the other hand, the oxidation of eight other PAHs occurred at slower rates and with coupling efficiencies that decreased with the enzyme reaction rate. Uncoupling was associated with hydrogen peroxide formation, which is potentially deleterious to cells and might inhibit PAH degradation. In single turnover reactions, ht-PhnI alone catalyzed PAH hydroxylation at a faster rate in the presence of organic solvent, suggesting that the transfer of substrate to the active site is a limiting factor. The four-ring PAHs chrysene and benz[a]anthracene were subjected to a double ring-dihydroxylation, giving rise to the formation of a significant proportion of bis-cis-dihydrodiols. In addition, the dihydroxylation of benz[a]anthracene yielded three dihydrodiols, the enzyme showing a preference for carbons in positions 1,2 and 10,11. This is the first characterization of a dioxygenase able to dihydroxylate PAHs made up of four and five rings. PMID:17014090

  16. Characterization of a Naphthalene Dioxygenase Endowed with an Exceptionally Broad Substrate Specificity Toward Polycyclic Aromatic Hydrocarbons

    SciTech Connect

    Jouanneau,Y.; Meyer, C.; Jakoncic, J.; Stojanoff, V.; Gaillard, J.

    2006-01-01

    In Sphingomonas CHY-1, a single ring-hydroxylating dioxygenase is responsible for the initial attack of a range of polycyclic aromatic hydrocarbons (PAHs) composed of up to five rings. The components of this enzyme were separately purified and characterized. The oxygenase component (ht-PhnI) was shown to contain one Rieske-type [2Fe-2S] cluster and one mononuclear Fe center per {alpha} subunit, based on EPR measurements and iron assay. Steady-state kinetic measurements revealed that the enzyme had a relatively low apparent Michaelis constant for naphthalene (K{sub m} = 0.92 {+-} 0.15 {mu}M) and an apparent specificity constant of 2.0 {+-} 0.3 M{sup -1} s{sup -1}. Naphthalene was converted to the corresponding 1,2-dihydrodiol with stoichiometric oxidation of NADH. On the other hand, the oxidation of eight other PAHs occurred at slower rates and with coupling efficiencies that decreased with the enzyme reaction rate. Uncoupling was associated with hydrogen peroxide formation, which is potentially deleterious to cells and might inhibit PAH degradation. In single turnover reactions, ht-PhnI alone catalyzed PAH hydroxylation at a faster rate in the presence of organic solvent, suggesting that the transfer of substrate to the active site is a limiting factor. The four-ring PAHs chrysene and benz[a]anthracene were subjected to a double ring-dihydroxylation, giving rise to the formation of a significant proportion of bis-cis-dihydrodiols. In addition, the dihydroxylation of benz[a]anthracene yielded three dihydrodiols, the enzyme showing a preference for carbons in positions 1,2 and 10,11. This is the first characterization of a dioxygenase able to dihydroxylate PAHs made up of four and five rings.

  17. Risk Assessment for Children Exposed to Beach Sands Impacted by Oil Spill Chemicals.

    PubMed

    Black, Jennifer C; Welday, Jennifer N; Buckley, Brian; Ferguson, Alesia; Gurian, Patrick L; Mena, Kristina D; Yang, Ill; McCandlish, Elizabeth; Solo-Gabriele, Helena M

    2016-01-01

    Due to changes in the drilling industry, oil spills are impacting large expanses of coastlines, thereby increasing the potential for people to come in contact with oil spill chemicals. The objective of this manuscript was to evaluate the health risk to children who potentially contact beach sands impacted by oil spill chemicals from the Deepwater Horizon disaster. To identify chemicals of concern, the U.S. Environmental Protection Agency's (EPA's) monitoring data collected during and immediately after the spill were evaluated. This dataset was supplemented with measurements from beach sands and tar balls collected five years after the spill. Of interest is that metals in the sediments were observed at similar levels between the two sampling periods; some differences were observed for metals levels in tar balls. Although PAHs were not observed five years later, there is evidence of weathered-oil oxidative by-products. Comparing chemical concentration data to baseline soil risk levels, three metals (As, Ba, and V) and four PAHs (benzo[a]pyrene, benz[a]anthracene, benzo[b]fluoranthene, and dibenz[a,h]anthracene) were found to exceed guideline levels prompting a risk assessment. For acute or sub-chronic exposures, hazard quotients, computed by estimating average expected contact behavior, showed no adverse potential health effects. For cancer, computations using 95% upper confidence limits for contaminant concentrations showed extremely low increased risk in the 10(-6) range for oral and dermal exposure from arsenic in sediments and from dermal exposure from benzo[a]pyrene and benz[a]anthracene in weathered oil. Overall, results suggest that health risks are extremely low, given the limitations of available data. Limitations of this study are associated with the lack of toxicological data for dispersants and oil-spill degradation products. We also recommend studies to collect quantitative information about children's beach play habits, which are necessary to more

  18. Sediment control of facilitated transport and enhanced desorption

    SciTech Connect

    Johnson, W.P.

    2000-01-01

    Laboratory column experiments examined the facilitated transport and enhanced desorption of benz(a)anthracene [B(a)A] by dissolved natural organic matter (OM) in sediments of low organic carbon content. The two-component experiments examining OM-sediment interaction and B(a)A-sediment interaction were modeled to determine the value of the linear rate constants describing transfer of B(a)A and OM between water and sediment. It was found that a two-rate approach better simulated B(a)A breakthrough and elution in the sediment relative to a one-rate approach. In contrast, OM-sediment interaction was well-simulated with a one-rate approach due to low OM sorption by sediment. The three-component experiments examining facilitated transport and enhanced desorption of B(a)A by dissolved OM, showed rapid linear reversible B(a)A-OM interaction. The value, within a factor of 2, of the equilibrium distribution constant for benz(a)anthracene distribution between water and OM was {approximately}1E6 for soil humic acid and {approximately}1E5 for Suwannee River humic acid. Simulations of the three-component experiments based on the equilibrium distribution constants for B(a)A-OM interaction and the rate constants determined from the two-component experiments were performed to determine whether rate constants differed in the two-component versus three-component systems. The simulations captured the major features of the facilitated transport and enhanced desorption data; however, discrepancies indicated that either the two-rate model for solute-sediment interaction was inappropriate, or that B(a)A transfer from sediment to dissolved OM was altered in the three-component system relative to the two-component system.

  19. Structurally distinct polycyclic aromatic hydrocarbons induce differential transcriptional responses in developing zebrafish

    SciTech Connect

    Goodale, Britton C.; Tilton, Susan C.; Corvi, Margaret M.; Wilson, Glenn R.; Janszen, Derek B.; Anderson, Kim A.; Waters, Katrina M.; Tanguay, Robert L.

    2013-11-01

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the environment as components of fossil fuels and by-products of combustion. These multi-ring chemicals differentially activate the aryl hydrocarbon receptor (AHR) in a structurally dependent manner, and induce toxicity via both AHR-dependent and -independent mechanisms. PAH exposure is known to induce developmental malformations in zebrafish embryos, and recent studies have shown cardiac toxicity induced by compounds with low AHR affinity. Unraveling the potentially diverse molecular mechanisms of PAH toxicity is essential for understanding the hazard posed by complex PAH mixtures present in the environment. We analyzed transcriptional responses to PAH exposure in zebrafish embryos exposed to benz(a)anthracene (BAA), dibenzothiophene (DBT) and pyrene (PYR) at concentrations that induced developmental malformations by 120 h post-fertilization (hpf). Whole genome microarray analysis of mRNA expression at 24 and 48 hpf identified genes that were differentially regulated over time and in response to the three PAH structures. PAH body burdens were analyzed at both time points using GC–MS, and demonstrated differences in PAH uptake into the embryos. This was important for discerning dose-related differences from those that represented unique molecular mechanisms. While BAA misregulated the least number of transcripts, it caused strong induction of cyp1a and other genes known to be downstream of the AHR, which were not induced by the other two PAHs. Analysis of functional roles of misregulated genes and their predicted regulatory transcription factors also distinguished the BAA response from regulatory networks disrupted by DBT and PYR exposure. These results indicate that systems approaches can be used to classify the toxicity of PAHs based on the networks perturbed following exposure, and may provide a path for unraveling the toxicity of complex PAH mixtures. - Highlights: • Defined global mRNA expression

  20. Degradation and Mineralization of High-Molecular-Weight Polycyclic Aromatic Hydrocarbons by Defined Fungal-Bacterial Cocultures

    PubMed Central

    Boonchan, Sudarat; Britz, Margaret L.; Stanley, Grant A.

    2000-01-01

    This study investigated the biodegradation of high-molecular-weight polycyclic aromatic hydrocarbons (PAHs) in liquid media and soil by bacteria (Stenotrophomonas maltophilia VUN 10,010 and bacterial consortium VUN 10,009) and a fungus (Penicillium janthinellum VUO 10,201) that were isolated from separate creosote- and manufactured-gas plant-contaminated soils. The bacteria could use pyrene as their sole carbon and energy source in a basal salts medium (BSM) and mineralized significant amounts of benzo[a]pyrene cometabolically when pyrene was also present in BSM. P. janthinellum VUO 10,201 could not utilize any high-molecular-weight PAH as sole carbon and energy source but could partially degrade these if cultured in a nutrient broth. Although small amounts of chrysene, benz[a]anthracene, benzo[a]pyrene, and dibenz[a,h]anthracene were degraded by axenic cultures of these isolates in BSM containing a single PAH, such conditions did not support significant microbial growth or PAH mineralization. However, significant degradation of, and microbial growth on, pyrene, chrysene, benz[a]anthracene, benzo[a]pyrene, and dibenz[a,h]anthracene, each as a single PAH in BSM, occurred when P. janthinellum VUO 10,201 and either bacterial consortium VUN 10,009 or S. maltophilia VUN 10,010 were combined in the one culture, i.e., fungal-bacterial cocultures: 25% of the benzo[a]pyrene was mineralized to CO2 by these cocultures over 49 days, accompanied by transient accumulation and disappearance of intermediates detected by high-pressure liquid chromatography. Inoculation of fungal-bacterial cocultures into PAH-contaminated soil resulted in significantly improved degradation of high-molecular-weight PAHs, benzo[a]pyrene mineralization (53% of added [14C]benzo[a]pyrene was recovered as 14CO2 in 100 days), and reduction in the mutagenicity of organic soil extracts, compared with the indigenous microbes and soil amended with only axenic inocula. PMID:10698765

  1. Squaraine PDT induces oxidative stress in skin tumor of swiss albino mice

    NASA Astrophysics Data System (ADS)

    Cibin, T. R.; Gayathri, Devi D.; Ramaiah, D.; Abraham, Annie

    2010-02-01

    Photodynamic Therapy (PDT) using a sensitizing drug is recognized as a promising medical technique for cancer treatment. It is a two step process that requires the administration of a photosensitizer followed by light exposure to treat a disease. Following light exposure the photosensitizer is excited to a higher energy state which generates free radicals and singlet oxygen. The present study was carried out to assess the oxidative damage induced by bis (3, 5-diiodo-2, 4, 6- trihydroxyphenyl) squaraine in skin tumor tissues of mice with/ without light treatment. Skin tumor was induced using 7, 12-Dimethyl Benz(a)anthracene and croton oil. The tumor bearing mice were given an intraperitoneal injection with the squaraine dye. After 24h, the tumor area of a few animals injected with the dye, were exposed to visible light from a 1000 W halogen lamp and others kept away from light. All the mice were sacrificed one week after the PDT treatment and the oxidative profile was analyzed (TBARS, SOD, catalase, GSH, GPx and GR) in tumor/ skin tissues. The dye induces oxidative stress in the tumor site only on illumination and the oxidative status of the tumor tissue was found to be unaltered in the absence of light. The results of the study clearly shows that the tumor destruction mediated by PDT using bis (3, 5-diiodo-2, 4, 6-trihydroxyphenyl) squaraine as a photosensitizer is due to the generation of reactive oxygen species, produced by the light induced changes in the dye.

  2. Metabolism and excretion of polycyclic aromatic hydrocarbons in rat and in human.

    PubMed

    Jacob, J; Grimmer, G

    1996-01-01

    Polycyclic aromatic hydrocarbons have shown to be an important class of environmental and occupational carcinogens. By balancing the carcinogenic potential PAH were found to predominantly contribute to the biological activity of environmental matter such as vehicle exhaust, used motor oil, and hard-coal combustion effluents. Due to the individual ratio of toxifying and detoxifying processes PAH-exposure measurements are not appropriate to be used for risk assessment without any further information on their metabolic fate. Accordingly, metabolite profiles of phenanthrene, pyrene, chrysene, benz(a)anthracene and fluoranthene have been recorded in both tar-pitch exposed Wistar rats and coke plant workers. The results show that metabolite profiles are invariant individual parameters which, however, vary from one individual to another. Significant differences with regard to the ratio of k-region and non-k-region hydroxylation of phenanthrene have been observed in a greater number of coke plant workers. This ratio might be helpful for risk assessment studies since it reflects the various cytochrome P450-dependent monooxygenase isoforms participating in the metabolism of PAH. Studies of this kind can only be carried out with substrates possessing several nonequivalent double bonds (phenanthrene, chrysene) whereas pyrene--commonly used for biomonitoring--does not satisfy this condition. The excretion rate (excretion versus exposure) seems to be an individual parameter. PMID:9167056

  3. Development of resistance to cyfluthrin and naphthalene among Daphnia magna.

    PubMed

    Brausch, John M; Smith, Philip N

    2009-07-01

    In this study, Daphnia magna were exposed to a pyrethroid insecticide (cyfluthrin) or a polycyclic aromatic hydrocarbon (naphthalene) for 12 generations to evaluate development of resistance followed by a 12 generation recovery period. Twenty-four hour old D. magna were exposed to concentrations of each chemical resulting in 50-70% mortality to select for the least sensitive individuals. LC50 values, survival, reproductive output, and time to first brood in stressor-exposed and control D. magna were recorded for each generation. Significant changes in LC50 values were observed after 4 generations and then declined after 6-10 generations post-exposure. D. magna were 5 times less sensitive to cyfluthrin and 3 times less sensitive to naphthalene as compared to controls after 12 generations of exposure. There were no differences in survival, time to first brood, or total number of offspring produced between control and either of the resistant F13 D. magna. Cyfluthrin exposed D. magna exhibited cross-resistance to DDT and methyl parathion, and naphthalene resistant D. magna were less sensitive than controls to both pyrene and benz(a)anthracene. When the cytochrome P450 inhibitor piperonyl butoxide was used in conjunction with cyfluthrin and naphthalene the sensitivity of resistant and control D. magna were equal, suggesting P450s were responsible for conveying resistance. This study demonstrates that life history and organisms' capacity to develop resistance is important to consider ensuring accuracy of ecological risk assessments. PMID:19399609

  4. Assessment of pollution of the Boca de Camichin Estuary in Nayarit (Mexico) and its influence on oxidative stress in Crassostrea corteziensis oysters.

    PubMed

    Toledo-Ibarra, G A; Díaz Resendiz, K J G; Ventura-Ramón, G H; Romero-Bañuelos, C A; Medina-Díaz, I M; Rojas-García, A E; Vega-López, A; Girón-Pérez, M I

    2016-10-01

    Boca de Camichin Estuary is one of the main producers of Crassostrea corteziensis oysters in Mexico, but the presence of pollutants can affect oyster production. Molluscs produce reactive oxygen species (ROS) in response to changes in the environment and pollution. These ROS induce oxidative damage in biomolecules. The main objective of this study was to evaluate pollution in the estuary and the subsequent oxidative stress in C. corteziensis oysters during the 2010 production cycle. For this aim, we performed monthly samplings in the oyster farms from January to May. We took water samples to quantify polycyclic aromatic hydrocarbon (PAH) and metal content; also, we evaluated oxidative damage (lipoperoxidation, lipidic hydroperoxides, protein oxidation) and enzyme activity (CAT, SOD, GPx, GST and AChE) in oyster gills. The results show the presence of Cu, Fe, Mn, naphthalene, benz[a]anthracene, pyrene, benz[a]pyrene and benzo[k]fluoranthene. On the other hand, AChE activity was not inhibited, which suggests that organophosphorus pollutants or carbamates were absent. Regarding oxidative stress, oysters from the estuary had oxidative damage in lipids, not proteins, and altered antioxidant enzyme activity, when compared to control organisms. Interestingly, we did not observe any correlation between the pollutants and the oxidative stress parameters evaluated in this study. Thus, we cannot rule out that a synergistic effect between the environmental variables and the pollutants is causing the oxidative stress in these oysters. PMID:27156678

  5. Preparation of environmental samples for the determination of polycyclic aromatic hydrocarbons by thin-layer chromatography.

    PubMed

    Poole, S K; Dean, T A; Poole, C F

    1987-07-29

    An evaluation of extraction procedures, liquid-liquid distribution systems, Sep-Pak cartridges, liquid-solid chromatography using silica, alumina and chemically modified silica packings (acid-base treated ethylammonium nitrate and picric acid impregnated), macroreticular resins and gel permeation columns for the analysis of polycyclic aromatic hydrocarbons (CPAHs) in environmental samples by thin-layer chromatography is discussed. For particulate samples solvent extraction using a Soxhlet apparatus or ultrasonication was found to be preferable to sublimation and liquid-liquid distribution between hexane and dimethyl sulfoxide followed by silica gel column chromatography was the preferred method for sample clean-up. Using this procedure enabled six PAHs (anthracene, fluoranthene, benz[a]anthracene, perylene, pyrene, and coronene) to be determined quantitatively in urban air particulate, diesel engine exhaust particulate, laboratory ventilator dust, household dust, river water, and tea samples. The PAHs were identified by coincidence of retention between the sample and standards in the same chromatographic system and by adequate agreement with standards for their normalized emission response ratios. The two-point calibration method was used for quantitation. Good agreement for the concentration of PAHs in the air particulate and diesel particulate extracts with published data using gas chromatography-mass spectrometry and high-performance liquid chromatography was found. PMID:2444609

  6. Langkocyclines: novel angucycline antibiotics from Streptomyces sp. Acta 3034(*).

    PubMed

    Kalyon, Bahar; Tan, Geok-Yuan A; Pinto, John M; Foo, Cheau-Yee; Wiese, Jutta; Imhoff, Johannes F; Süssmuth, Roderich D; Sabaratnam, Vikineswary; Fiedler, Hans-Peter

    2013-10-01

    Langkocyclines A1-A3 and B1 and B2, five new angucycline antibiotics produced by Streptomyces sp. Acta 3034, were detected in the course of our HPLC-diode array screening. The producing strain was isolated from the rhizospheric soil of a Clitorea sp. collected from Burau Bay, Langkawi, Malaysia, and was characterized by morphological, physiological and chemotaxonomic features in addition to 16S ribosomal RNA gene sequence information. Strain Acta 3034 is closely related to Streptomyces psammoticus NBRC 13971(T) and Streptomyces lanatus NBRC 12787(T). Langkocyclines consist of an angular tetracyclic benz[a]anthracene skeleton and hydrolyzable O-glycosidic sugar moieties. The yellow-colored A-type langkocyclines differ in their aglycon from the blue-lilac-colored B-type langkocyclines. The A-type langkocycline aglycon is identical to that of aquayamycin and urdamycin A. The chemical structures of the langkocyclines were elucidated by HR-MS, 1D and 2D NMR experiments. They are biologically active against Gram-positive bacteria and exhibit a moderate antiproliferative activity against various human tumor cell lines. PMID:23820614

  7. Comparison of polycyclic aromatic hydrocarbons level between suspended solid and sediment samples of Pengkalan Chepa River, Kelantan state, Malaysia

    NASA Astrophysics Data System (ADS)

    Muslim, Noor Zuhartini Md; Babaheidari, Seyedreza Hashemi; Zakaria, Mohamad Pauzi

    2015-09-01

    Sixteen type of common Polycyclic Aromatic Hydrocarbons (PAHs) which consist of naphthalene, acenaphthene, acenaphthylene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, benzo[ghi]-perylene, indeno[1,2,3-cd]-pyrene and dibenz[a,h]-anthracene in suspended solid and sediment samples of Pengkalan Chepa River, Kelantan state, Malaysia were investigated. The analysis samples were taken from six different sites of Pengkalan Chepa River during sunny day. The samples were subjected to a series of pre-treatment before the level of PAHs can be determined. A Gas Chromatography-Mass Spectrometry (GC-MS) was the prime method for the analysis of PAHs level. A total of 16 PAHs concentration in suspended solid of the whole Pengkalan Chepa River was found to be 2144.6 ng/g dry weights. This concentration was about eight times more than 16 PAHs concentration in sediment which found to be 266.5 ng/g dry weights.

  8. Relative induction of a biomarker, P450 RGS, by PAHs and chlorinated hydrocarbons

    SciTech Connect

    Bothner, K.; Anderson, J. |

    1995-12-31

    A reporter gene system (RGS) assay has been engineered from a human liver cancer cell fine so that the induction of CPA gene will result in the production of luciferase (firefly plasmid) instead of cytochrome P450. Induction of this test system by compounds such as polycyclic aromatic hydrocarbons (PAHs) and chlorinated hydrocarbons infers these xenobiotics are present at levels that are potentially toxic, carcinogenic, or mutagenic to organisms. Six well plates with 1.0 {times} 10{sup 6} adhered cells in 2 mLs of media are inoculated with varying volumes of organic solvents containing a reference toxicant (TCDD) and sample extracts. Solvent extracts (EPA 3540) of aquatic sediments, soils, and mussel tissue have been applied directly to this system. Test results show a significant RGS induction from concentrations of PAHs, that if present in a 40 gram sediment sample, would be (in ng/g or ppb): 20 for dibenz(a,h)anthracene; 70 for benz(a)anthracene; 100 for benzo(a)pyrene; and 250 for chrysene. Testing with mixtures of PAHs and environmental samples has shown that levels of 300 to 400 ppb are detected. Results to be presented from P450 RGS testing will show that the estimated health risk (Toxic Equivalent Factors, TEFs) of some of the PAHs may be as great or greater than some of the coplanar PCB.

  9. The response of Ty1 test to genotoxins.

    PubMed

    Pesheva, M; Krastanova, O; Stamenova, R; Kantardjiev, D; Venkov, P

    2008-10-01

    The Ty1 assay is a short-term test for detection of genotoxins based on induction of the transposition of a gene-engineered Ty1 retrotransposon in Saccharomyces cerevisiae cells. Here, we provide evidence that the Ty1 test responds positively in concentration-dependent manner to the carcinogenic genotoxins benz(a)anthracene, benzo(a)pyrene, chenodeoxycholic and taurodeoxycholic free bile acids and to environmental soil samples polluted with carcinogenic substances. The Ty1 test gives negative results with the noncarcinogenic mutagens benz(b)anthracene, benzo(e)pyrene, lithocholic and taurodeoxycholic conjugated bile acids and to soil samples not polluted with carcinogens. Presence or absence of genotoxins in soil samples was evidenced by chemical analysis. Several explanations for the sensitive differential test's response to genotoxins are proposed and discussed. It is concluded that the Ty1 test can complement existing assays in laboratory and environmental studies showing high sensitivity to a wider spectrum of carcinogenic genotoxins. PMID:18369596

  10. Laccase oxidation and removal of toxicants released during combustion processes.

    PubMed

    Prasetyo, Endry Nugroho; Semlitsch, Stefan; Nyanhongo, Gibson S; Lemmouchi, Yahia; Guebitz, Georg M

    2016-02-01

    This study reports for the first time the ability of laccases adsorbed on cellulose acetate to eliminate toxicants released during combustion processes. Laccases directly oxidized and eliminated more than 40% w/v of 14 mM of 1,4-dihydroxybenzene (hydroquinone); 2-methyl-1,4-benzenediol (methylhydroquinone); 1,4-dihydroxy-2,3,5-trimethylbenzene (trimethylhydroquinone); 3-methylphenol (m-cresol); 4-methylphenol (p-cresol); 2-methylphenol (o-cresol); 1,3-benzenediol (resorcinol); 1,2-dihydroxybenzene (catechol); 3,4-dihydroxytoluene (4-methylcatechol) and 2-naphthylamine. Further, laccase oxidized 2-naphthylamine, hydroquinone, catechol, methylhydroquinone and methylcatechol were also able to in turn mediate the elimination of >90% w/v of toxicants which are per-se non-laccase substrates such as 3-aminobiphenyl; 4-aminobiphenyl; benz[a]anthracene; 3-(1-nitrosopyrrolidin-2-yl) pyridine (NNN); formaldehyde; 4-(methyl-nitrosamino-1-(3-pyridyl)-1-butanone (NNK); 2-butenal (crotonaldehyde); nitric oxide and vinyl cyanide (acrylonitrile). These studies demonstrate the potential of laccase immobilized on solid supports to remove many structurally different toxicants released during combustion processes. This system has great potential application for in situ removal of toxicants in the manufacturing, food processing and food service industries. PMID:26408262

  11. A simple methodological validation of the gas/particle fractionation of polycyclic aromatic hydrocarbons in ambient air

    NASA Astrophysics Data System (ADS)

    Kim, Yong-Hyun; Kim, Ki-Hyun

    2015-07-01

    The analysis of polycyclic aromatic hydrocarbons (PAH) in ambient air requires the tedious experimental steps of both sampling and pretreatment (e.g., extraction or clean-up). To replace pre-existing conventional methods, a simple, rapid, and novel technique was developed to measure gas-particle fractionation of PAH in ambient air based on ‘sorbent tube-thermal desorption-gas chromatograph-mass spectrometer (ST-TD-GC-MS)’. The separate collection and analysis of ambient PAHs were achieved independently by two serially connected STs. The basic quality assurance confirmed good linearity, precision, and high sensitivity to eliminate the need for complicated pretreatment procedures with the detection limit (16 PAHs: 13.1 ± 7.04 pg). The analysis of real ambient PAH samples showed a clear fractionation between gas (two-three ringed PAHs) and particulate phases (five-six ringed PAHs). In contrast, for intermediate (four ringed) PAHs (fluoranthene, pyrene, benz[a]anthracene, and chrysene), a highly systematic/gradual fractionation was established. It thus suggests a promising role of ST-TD-GC-MS as measurement system in acquiring a reliable database of airborne PAH.

  12. Fate and Transport of Polycyclic Aromatic Hydrocarbons in Upland Irish Headwater Lake Catchments

    PubMed Central

    Scott, Heidi E. M.; Aherne, Julian; Metcalfe, Chris D.

    2012-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are a concern due to their carcinogenicity and propensity for transboundary atmospheric transport. Ireland is located on the western periphery of Europe and assumed to receive clean Atlantic air. As such, it has been used as an atmospheric reference for comparison to other regions. Nonetheless, few studies have evaluated concentrations of PAHs within the Irish environment. In the current study, PAHs were measured at five upland (500–800 masl) headwater lake catchments in coastal regions around Ireland, remote from industrial point source emissions. Semipermeable membrane devices were deployed in lakes for a 6-month period in July 2009, and topsoils were sampled from each catchment during October 2010. The concentrations of PAHs were low at most study sites with respect to other temperate regions. Homologue groups partitioned between lake and soil compartments based on their molecular weight were: “lighter” substances, such as Phenanthrene and Fluorene, were found in higher proportions in lakes, whereas “heavier” compounds, such as Chrysene and Benz[a]anthracene, were more prominent in soils. Concentrations of PAHs were highest at the east coast sites, potentially due to contributions from historical transboundary and regional combustion sources. PMID:23346024

  13. Urinary profiles to assess polycyclic aromatic hydrocarbons exposure in coke-oven workers.

    PubMed

    Campo, Laura; Rossella, Federica; Pavanello, Sofia; Mielzynska, Danuta; Siwinska, Ewa; Kapka, Lucyna; Bertazzi, Pier Alberto; Fustinoni, Silvia

    2010-01-15

    Aim of the study was the assessment of exposure of coke-oven workers to polycyclic aromatic hydrocarbons (PAHs) by determination of urinary profiles of hydroxylated and unmetabolized PAHs. Fifty-five Polish coke-oven workers were investigated by measurement of 12 hydroxylated metabolites of PAHs (OHPAHs) (1-, 2-hydroxynaphthalene; 2-, 9-hydroxyfluorene; 1-, 2-, 3-, 4-, 9-hydroxyphenanthrene; 1-hydroxyypyrene, 6-hydroxychrysene and 3-hydroxybenzo[a]pyrene) and 13 unmetabolized PAHs (U-PAHs) (from naphthalene to benzo[a]pyrene), in spot urine samples collected at the end of the workshift. U-PAHs with four or less rings were detected in all samples. In particular, median levels for urinary naphthalene, phenanthrene, pyrene, chrysene and benz[a]anthracene were 0.806, 0.721, 0.020, 0.032 and 0.035 microg/L. OHPAHs up to 1-hydroxypyrene were found in all samples, while high molecular-weight OHPAHs were always below quantification limit. Median level of 1-hydroxyypyrene was 15.4 microg/L. In all subjects significant correlations between OHPAHs and U-PAHs were observed (0.27 < r < 0.70, p < 0.01). Our results suggest that both hydroxylated metabolites and unmetabolized PAHs in urine are useful biomarkers of exposure to PAHs. Moreover, the simultaneous determination of several biomarkers permits to obtain specific excretion profiles that might help in exposure characterization and in better defining the excretion patterns. PMID:20143505

  14. Transformation of PAHs during ethanol-Fenton treatment of an aged gasworks' soil.

    PubMed

    Lundstedt, Staffan; Persson, Ylva; Oberg, Lars

    2006-11-01

    PAH-contaminated soil from a former gasworks site was treated with Fenton's reagent in a number of lab-scale slurry reactors. The degradation result obtained by traditional Fenton oxidation and Fenton oxidation preceded by ethanol treatment were compared. The ethanol pre-treatment enhanced the depletion of all PAHs in the soil by facilitating their desorption from the soil matrix. However, some PAHs, especially anthracene, benzo[a]pyrene and perylene, were more extensively depleted than other PAHs with fewer or equal numbers of fused rings, indicating that the hydroxyl radicals react faster with these PAHs than with other kinds. The ethanol present in the slurry also appeared to influence the relative reactivity of the PAHs. Furthermore, the enhanced oxidation that occurred in the ethanol pre-treated soil resulted in the accumulation of oxidation products. For example, 1-indanone, anthracene-9,10-dione, 1-methylanthracenedione, 2-methylanthracenedione, 1,8-naphthalic anhydride, benz[a]anthracene-7,12-dione and two compounds tentatively identified as hydroxy-9-fluorenones were found at higher concentrations after the treatment than before it. The accumulation was most evident for the quinones, and in many cases it could be attributed to extensive oxidation of their parent PAHs, although the total oxidation efficiency in this study was relatively poor. PMID:16735053

  15. Heterologous Expression of Polycyclic Aromatic Hydrocarbon Ring-Hydroxylating Dioxygenase Genes from a Novel Pyrene-Degrading Betaproteobacterium

    PubMed Central

    Hu, Jing; Aitken, Michael D.

    2012-01-01

    A betaproteobacterium within the family Rhodocyclaceae previously identified as a pyrene degrader via stable-isotope probing (SIP) of contaminated soil (designated pyrene group 1 or PG1) was cultivated as the dominant member of a mixed bacterial culture. A metagenomic library was constructed, and the largest contigs were analyzed for genes associated with polycyclic aromatic hydrocarbon (PAH) metabolism. Eight pairs of genes with similarity to the α- and β-subunits of ring-hydroxylating dioxygenases (RHDs) associated with aerobic bacterial PAH degradation were identified and linked to PG1 through PCR analyses of a simplified enrichment culture. In tandem with a ferredoxin and reductase found in close proximity to one pair of RHD genes, six of the RHDs were cloned and expressed in Escherichia coli. Each cloned RHD was tested for activity against nine PAHs ranging in size from two to five rings. Despite differences in their predicted protein sequences, each of the six RHDs was capable of transforming phenanthrene and pyrene. Three RHDs could additionally transform naphthalene and fluorene, and these genotypes were also associated with the ability of the E. coli constructs to convert indole to indigo. Only one of the six cloned RHDs was capable of transforming anthracene and benz[a]anthracene. None of the tested RHDs were capable of significantly transforming fluoranthene, chrysene, or benzo[a]pyrene. PMID:22427500

  16. Modeling the formation of some polycyclic aromatic hydrocarbons during the roasting of Arabica coffee samples.

    PubMed

    Houessou, Justin Koffi; Goujot, Daniel; Heyd, Bertrand; Camel, Valerie

    2008-05-28

    Roasting is a critical process in coffee production, as it enables the development of flavor and aroma. At the same time, roasting may lead to the formation of nondesirable compounds, such as polycyclic aromatic hydrocarbons (PAHs). In this study, Arabica green coffee beans from Cuba were roasted under controlled conditions to monitor PAH formation during the roasting process. Roasting was performed in a pilot-spouted bed roaster, with the inlet air temperature varying from 180 to 260 degrees C, for roasting conditions ranging from 5 to 20 min. Several PAHs were determined in both roasted coffee samples and green coffee samples. Different models were tested, with more or less assumptions on the chemical phenomena, with a view to predict the system global behavior. Two kinds of models were used and compared: kinetic models (based on Arrhenius law) and statistical models (neural networks). The numbers of parameters to adjust differed for the tested models, varying from three to nine for the kinetic models and from five to 13 for the neural networks. Interesting results are presented, with satisfactory correlations between experimental and predicted concentrations for some PAHs, such as pyrene, benz[a]anthracene, chrysene, and anthracene. PMID:18433138

  17. Raman spectroscopic investigation of the chemopreventive response of naringenin and its nanoparticles in DMBA-induced oral carcinogenesis

    NASA Astrophysics Data System (ADS)

    Krishnakumar, N.; Sulfikkarali, N. K.; Manoharan, S.; Venkatachalam, P.

    2013-11-01

    Raman spectroscopy is a vibrational spectroscopic technique that can be used to optically probe the biomolecular changes associated with tumor progression. The aim of the present study is to investigate the biomolecular changes in chemopreventive response of prepared naringenin-loaded nanoparticles (NARNPs) relative to efficacy of free naringenin (NAR) during 7,12-dimethyl benz(a)anthracene (DMBA)-induced oral carcinogenesis by Fourier Transform Raman (FT-Raman) spectroscopy. Oral squamous cell carcinoma (OSCC) was developed in the buccal pouch of golden Syrian hamsters by painting with 0.5% DMBA in liquid paraffin three times a week for 14 weeks. Raman spectra differed significantly between the control and tumor tissues, with tumors showing higher percentage signals for nucleic acids, phenylalanine and tryptophan and a lower in the percentage of phospholipids. Moreover, oral administration of free NAR and NARNPs significantly increased phospholipids and decreased the levels of tryptophan, phenylalanine and nucleic acid contents. On a comparative basis, NARNPs was found to have a more potent antitumor effect than free NAR in completely preventing the formation of squamous cell carcinoma and in improving the biochemical status to a normal range in DMBA-induced oral carcinogenesis. The present study further suggest that Raman spectroscopy could be a valuable tool for rapid and sensitive detection of specific biomolecular changes in response to chemopreventive agents.

  18. Development of a reference artificial sediment for chemical testing adapted to the MELA sediment contact assay.

    PubMed

    Le Bihanic, Florane; Perrichon, Prescilla; Landi, Laure; Clérandeau, Christelle; Le Menach, Karyn; Budzinski, Hélène; Cousin, Xavier; Cachot, Jérôme

    2014-12-01

    Most persistent organic pollutants, due to their hydrophobic properties, accumulate in aquatic sediments and represent a high risk for sediment quality. To assess the toxicity of hydrophobic pollutants, a novel approach was recently proposed as an alternative to replace, refine and reduce animal experimentation: the medaka embryo-larval sediment contact assay (MELAc). This assay is performed with Japanese medaka embryos incubated on a natural sediment spiked with the compound being tested. With the aim of improving this assay, our study developed a reference exposure protocol with an artificial sediment specifically designed to limit natural sediment composition uncertainties and preparation variability. The optimum composition of the new artificial sediment was tested using a model polycyclic aromatic hydrocarbon (PAH), fluoranthene. The sediment was then validated with two other model PAHs, benz[a]anthracene and benzo[a]pyrene. Various developmental end points were recorded, including survival, embryonic heartbeat, hatching delay, hatching success, larval biometry and abnormalities. The final artificial sediment composition was set at 2.5 % dry weight (dw) Sphagnum peat, 5 % dw kaolin clay and 92.5 % dw silica of 0.2- to 0.5-mm grain size. In contrast with natural sediments, the chemical components of this artificial matrix are fully defined and readily identifiable. It is totally safe for fish embryos and presents relatively high sorption capacities for hydrophobic compounds. Studies with other hydrophobic and metallic contaminants and mixtures should be performed to further validate this artificial sediment. PMID:24526399

  19. Low intake of polycyclic aromatic hydrocarbons in Sweden: results based on market basket data and a barbecue study.

    PubMed

    Abramsson-Zetterberg, Lilianne; Darnerud, Per Ola; Wretling, Sören

    2014-12-01

    In a market basket study made at the National Food Agency in Sweden, in which the most common consumed foodstuffs are sampled, the content of polycyclic aromatic hydrocarbons (PAH), benzo(a)pyrene (B(a)P) and PAH4 (B(a)P, chrysene, benzo(b)fluoranthene, and benz(a)anthracene) were analysed. To this data, results on B(a)P and PAH4 levels originating from a home-barbecue-study on sausages and loin of pork were added. The calculated total mean intake of B(a)P and PAH4 was 50 ng/person and day 276 ng/person and day, respectively. Sugar and sweets, cereal products, meat, and dairy products contributed most to the total intake. In case of PAH concentrations below LOD, 0.03 µg/kg, ½ LOD was used in the intake calculations. The highest mean level of B(a)P and PAH4 were found in the barbecued products, but since the estimated consumption in Sweden is low, the contribution to the total food intake is almost negligible, about 2%. The calculated B(a)P levels in food has decreased during the last 10 years and indicates a low cancer risk for the Swedish population. PMID:25261863

  20. Volatility of organic molecular markers used for source apportionment analysis: measurements and implications for atmospheric lifetime.

    PubMed

    May, Andrew A; Saleh, Rawad; Hennigan, Christopher J; Donahue, Neil M; Robinson, Allen L

    2012-11-20

    Molecular markers are organic species used to define fingerprints for source apportionment of ambient fine particulate matter. Traditionally, these markers have been assumed to be stable in the atmosphere. This work investigates the gas-particle partitioning of eight organic species used as molecular markers in receptor models for biomass burning (levoglucosan), motor vehicles (5α-cholestane, n-hexacosane, n-triacontane, 1,2-benz[a]anthracene, coronene), and meat cooking (cholesterol, oleic acid). Experiments were conducted using a thermodenuder to measure the evaporation of single component particles. The data were analyzed using the integrated volume method to determine saturation concentrations and enthalpies of vaporization for each compound. The results indicate that appreciable quantities (>10%) of most of these markers exist in the gas phase under typical atmospheric conditions. Therefore, these species should be considered semivolatile. Predictions from a chemical kinetics model indicate that gas-particle partitioning has important effects on the atmospheric lifetime of these species. The atmospheric decay of semivolatile compounds proceeds much more rapidly than nonvolatile compounds because gas-phase oxidation induces evaporation of particle-phase material. Therefore, both gas-particle partitioning and chemical reactions need to be accounted for when semivolatile molecular markers are used for source apportionment studies. PMID:23013599

  1. Determining biotransformation rates of PAH in fish using a static exposure system

    SciTech Connect

    Maagd, P.G.J. de; Sijm, D.T.H.M.; Opperhuizen, A.

    1994-12-31

    In-order to quantify the influence of biotransformation on bioconcentration, juvenile fathead minnows were exposed to aqueous solutions of PAH under static conditions. During the two days of exposure both fish and water samples were taken and analyzed to determine the change in PAH concentrations in both phases with time. A numerical mathematical model was developed to calculate uptake rate constants (k{sub 1}), physico-chemical elimination rate constants (k{sub m}) and biotransformation rate constants (k{sub 2}) from concentrations in fish and water. The model assumes that biotransformation is the only process that is responsible for loss of PAH from the fish-water system. Control experiments were performed to correct for evaporation, degradation and sorption. Of the PAH tested so far (naphthalene, anthracene, phenanthrene, fluoranthene and benzo[a]anthracene) the influence of biotransformation on bioconcentration is most significant for benzo[a]anthracene and fluoranthene. Biotransformation reduced the bioconcentration of benz[a]anthracene with about an order of magnitude.

  2. EU marker polycyclic aromatic hydrocarbons in food supplements: analytical approach and occurrence

    PubMed Central

    Zelinkova, Zuzana; Wenzl, Thomas

    2015-01-01

    Several food supplements comprising botanical, oil and bee products collected from retail markets in different countries were tested for the occurrence of 4 EU marker Polycyclic aromatic hydrocarbons (PAHs; benz[a]anthracene, chrysene, benzo[b]fluoranthene and benzo[a]pyrene). A robust GC/MS-based stable-isotope dilution method was used taking into account the differences in the type of matrices. The accuracy of the results was assessed by implementing several quality control tools. Sixty-eight samples of 94 analysed products exceeded the level of 0.5 μg/kg for the sum of the four EU marker PAHs (ΣPAH4). Benzo[a]pyrene exceeded the limit of quantification in 49 samples. The PAH with the highest abundance in all products was chrysene. On average, propolis extracts and other bee products showed relatively high levels of ΣPAH4 (mean 188.2 μg/kg), whereas the contamination levels of fish oil supplements were very low or mostly undetectable. Considerably high ΣPAH4 amounts found in some samples could remarkably increase the daily exposure of consumers to PAHs, demonstrating the need for continuous monitoring of ΣPAH4 in food supplements. PMID:26467752

  3. A simple methodological validation of the gas/particle fractionation of polycyclic aromatic hydrocarbons in ambient air.

    PubMed

    Kim, Yong-Hyun; Kim, Ki-Hyun

    2015-01-01

    The analysis of polycyclic aromatic hydrocarbons (PAH) in ambient air requires the tedious experimental steps of both sampling and pretreatment (e.g., extraction or clean-up). To replace pre-existing conventional methods, a simple, rapid, and novel technique was developed to measure gas-particle fractionation of PAH in ambient air based on 'sorbent tube-thermal desorption-gas chromatograph-mass spectrometer (ST-TD-GC-MS)'. The separate collection and analysis of ambient PAHs were achieved independently by two serially connected STs. The basic quality assurance confirmed good linearity, precision, and high sensitivity to eliminate the need for complicated pretreatment procedures with the detection limit (16 PAHs: 13.1 ± 7.04 pg). The analysis of real ambient PAH samples showed a clear fractionation between gas (two-three ringed PAHs) and particulate phases (five-six ringed PAHs). In contrast, for intermediate (four ringed) PAHs (fluoranthene, pyrene, benz[a]anthracene, and chrysene), a highly systematic/gradual fractionation was established. It thus suggests a promising role of ST-TD-GC-MS as measurement system in acquiring a reliable database of airborne PAH. PMID:26126962

  4. Removal of polycyclic aromatic hydrocarbons from soil: a comparison between bioremoval and supercritical fluids extraction.

    PubMed

    Amezcua-Allieri, M A; Ávila-Chávez, M A; Trejo, A; Meléndez-Estrada, J

    2012-03-01

    Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic substances which are resistant to environmental degradation due to their highly hydrophobic nature. Soils contaminated with PAHs pose potential risks to human and ecological health, therefore concern over their adverse effects have resulted in extensive studies on their removal from contaminated soils. The main purpose of this study was to compare experimental results of PAHs removal, from a natural certified soil polluted with PAHs, by biological methods (using bioaugmentation and biostimulation in a solid-state culture) with those from supercritical fluid extraction (SFE), using supercritical ethane as solvent. The comparison of results between the two methods showed that maximal removal of naphthalene, acenaphthene, fluorene, and chrysene was performed using bioremediation; however, for the rest of the PAHs considered (fluoranthene, pyrene, and benz(a)anthracene) SFE resulted more efficient. Although bioremediation achieved higher removal ratios for certain hydrocarbons and takes advantage of the increased rate of natural biological processes, it takes longer time (i.e. 36 d vs. half an hour) than SFE and it is best for 2-3 PAHs rings. PMID:22197016

  5. Strong synergistic induction of CYP1A1 expression by andrographolide plus typical CYP1A inducers in mouse hepatocytes

    SciTech Connect

    Jaruchotikamol, Atika; Jarukamjorn, Kanokwan Sirisangtrakul, Wanna; Sakuma, Tsutomu; Kawasaki, Yuki; Nemoto, Nobuo

    2007-10-15

    The effects of andrographolide, the major diterpenoid constituent of Andrographis paniculata, on the expression of cytochrome P450 superfamily 1 members, including CYP1A1, CYP1A2, and CYP1B1, as well as on aryl hydrocarbon receptor (AhR) expression in primary cultures of mouse hepatocytes were investigated in comparison with the effects of typical CYP1A inducers, including benz[a]anthracene, {beta}-naphthoflavone, and 2,3,7,8-tetrachlorodibenzo-p-dioxin. Andrographolide significantly induced the expression of CYP1A1 and CYP1A2 mRNAs in a concentration-dependent manner, as did the typical CYP1A inducers, but did not induce that of CYP1B1 or AhR. Interestingly, andrographolide plus the typical CYP1A inducers synergistically induced CYP1A1 expression, and the synergism was blocked by an AhR antagonist, resveratrol. The CYP1A1 enzyme activity showed a similar pattern of induction. This is the first report that shows that andrographolide has a potency to induce CYP1A1 enzyme and indicates that andrographolide could be a very useful compound for investigating the regulatory mechanism of the CYP1A1 induction pathway. In addition, our findings suggest preparing advice for rational administration of A. paniculata, according to its ability to induce CYP1A1 expression.

  6. Differential expression of CYP1A1 and CYP1A2 genes in H4IIE rat hepatoma cells exposed to TCDD and PAHs.

    PubMed

    Kaisarevic, Sonja; Dakic, Vanja; Hrubik, Jelena; Glisic, Branka; Lübcke-von Varel, Urte; Pogrmic-Majkic, Kristina; Fa, Svetlana; Teodorovic, Ivana; Brack, Werner; Kovacevic, Radmila

    2015-01-01

    Rat hepatoma cells H4IIE were treated by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and polycyclic aromatic hydrocarbons (PAHs) (dibenz(a,h)anthracene, benzo(a)pyrene, benz(a)anthracene, chrysene), low-concentration mixtures of PAHs and TCDD, and environmental mixtures contaminated by PAHs and their derivatives. Expression of the gene battery comprising cytochrome P450 Cyp1a1, Cyp1a2, Cyp1b1, and glutathione-s-transferase Gsta2 and Gstp was investigated using quantitative real time polymerase chain reaction (qRT-PCR) analysis. The results revealed that TCDD induce Cyp1a1>Cyp1a2>Cyp1b1, while PAHs and PAH-containing environmental mixtures induce Cyp1a2>Cyp1a1>Cyp1b1 gene expression pattern. While low-concentration mixtures elicited a more pronounced response in comparison to single treatments, the typical gene expression patterns were not observed. In all samples, Gsta2 was predominantly expressed relative to Gstp. These findings indicate that differential Cyp1a1 and Cyp1a2 expression in the H4IIE cells might be used for detection of PAHs in highly contaminated environmental mixtures, but not in low-concentration mixtures of these compounds. PMID:25555259

  7. Sample preparation of sewage sludge and soil samples for the determination of polycyclic aromatic hydrocarbons based on one-pot microwave-assisted saponification and extraction.

    PubMed

    Pena, M Teresa; Pensado, Luis; Casais, M Carmen; Mejuto, M Carmen; Cela, Rafael

    2007-04-01

    A microwave-assisted sample preparation (MASP) procedure was developed for the analysis of polycyclic aromatic hydrocarbons (PAHs) in sewage sludge and soil samples. The procedure involved the simultaneous microwave-assisted extraction of PAHs with n-hexane and the hydrolysis of samples with methanolic potassium hydroxide. Because of the complex nature of the samples, the extracts were submitted to further cleaning with silica and Florisil solid-phase extraction cartridges connected in series. Naphthalene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[e]pyrene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenz[a,h]anthracene, benzo[g,h,i]perylene, and indeno[1,2,3-cd]pyrene, were considered in the study. Quantification limits obtained for all of these compounds (between 0.4 and 14.8 microg kg(-1) dry mass) were well below of the limits recommended in the USA and EU. Overall recovery values ranged from 60 to 100%, with most losses being due to evaporation in the solvent exchange stages of the procedure, although excellent extraction recoveries were obtained. Validation of the accuracy was carried out with BCR-088 (sewage sludge) and BCR-524 (contaminated industrial soil) reference materials. PMID:17268774

  8. Critical body residues in the marine amphipod Ampelisca abdita: Sediment exposures with nonionic organic contaminants

    SciTech Connect

    Fay, A.A.; Brownawell, B.J.; Elskus, A.A.; McElroy, A.E.

    2000-04-01

    Body residues associated with acute toxicity were determined in the marine amphipod Ampelisca abdita exposed to spiked sediments. Nonylphenol and 2,2{prime},4,4{prime}-tetrachlorobiphenyl critical body residues (CBRs, body residue of contaminant at 50% mortality) were 1.1 {micro}mol/g wet tissue and 0.57 {micro}mol/g wet tissue, respectively, values near the low end of the CBR range expected for compounds acting via narcosis. The polycyclic aromatic hydrocarbons tested, benzo[a]pyrene (BaP) and benz[a]anthracene (BaA), were not acutely toxic at exposure concentrations of up to 43 and 1,280 {micro}g/g dry sediment for BaA and BaP respectively, and body burdens up to 1.2 {micro}mol/g wet tissue (for BaP). Neither polycyclic aromatic hydrocarbon (PAH) was significantly metabolized by A. abdita. The microextraction technique employed here allowed residue analysis of samples containing as few as three amphipods (0.33 mg dry wt). The CBR approach avoids confounding factors such as variations in bioavailability and uptake kinetics and could be employed to assess the relative contribution of specific contaminants or contaminant classes in mixtures to effects observed in toxicity tests with Ampelisca and other organisms.

  9. Mass balances on selected polycyclic aromatic hydrocarbons in the New York-New Jersey Harbor.

    PubMed

    Rodenburg, Lisa A; Valle, Sandra N; Panero, Marta A; Muñoz, Gabriela R; Shor, Leslie M

    2010-01-01

    Mass balances on 10 polycyclic aromatic hydrocarbons (PAHs) in the New York-New Jersey Harbor (hereafter "the Harbor") were constructed using monitoring data from the water column, sediment, and atmosphere. Inputs considered included tributaries, atmospheric deposition, wastewater treatment plant discharges, combined sewer overflows (CSOs), and stormwater runoff. Removal processes examined included tidal exchange between the Harbor and the coastal Bight and Long Island Sound, volatilization, and accumulation or burial of sediment-bound PAHs in the Harbor. The PAHs investigated were fluorene, phenanthrene, fluoranthene, pyrene, benz[a]anthracene, benzo[a]pyrene, perylene, benzo[ghi]perylene, indeno[1,2,3-cd]pyrene, and dibenz[a,h]anthracene. The results show inputs and outputs are fairly well balanced for most compounds, a finding that suggests aerobic biodegradation may not be a key loss process in this Harbor, as has been assumed in other systems. The main pathway for inputs of all PAHs is stormwater runoff. Atmospheric deposition is an important conveyor of PAHs with molecular weights < or =202 g mol(-1). A principal objective of this report is to expose key data gaps, which include the need for comprehensive monitoring of both flow and PAH concentrations in stormwater and CSOs. An improved understanding of the key transmission routes of nonpoint source pollutants is essential for sustainable management of urban water resources. PMID:20176837

  10. Chemometrics-assisted excitation-emission fluorescence spectroscopy on nylon-attached rotating disks. Simultaneous determination of polycyclic aromatic hydrocarbons in the presence of interferences.

    PubMed

    Cañas, Alejandro; Richter, Pablo; Escandar, Graciela M

    2014-12-10

    This work presents a green and very simple approach which enables the accurate and simultaneous determination of benzo[a]pyrene, dibenz[a,h]anthracene, benz[a]anthracene, and chrysene, concerned and potentially carcinogenic heavy-polycyclic aromatic hydrocarbons (PAHs) in interfering samples. The compounds are extracted from water samples onto a device composed of a small rotating Teflon disk, with a nylon membrane attached to one of its surfaces. After extraction, the nylon membrane containing the concentrated analytes is separated from the Teflon disk, and fluorescence excitation-emission matrices are directly measured on the nylon surface, and processed by applying parallel factor analysis (PARAFAC), without the necessity of a desorption step. Under optimum conditions and for a sample volume of 25 mL, the PAHs extraction was carried out in 20 min. Detection limits based on the IUPAC recommended criterion and relative errors of prediction were in the ranges 20-100 ng L(-1) and 5-7%, respectively. Thanks to the combination of the ability of nylon to strongly retain PAHs, the easy rotating disk extraction approach, and the selectivity of second-order calibration, which greatly simplifies sample treatment avoiding the use of toxic solvents, the developed method follows most green analytical chemistry principles. PMID:25441886

  11. Areal distribution and concentrations of contaminants of concern in surficial streambed and lakebed sediments, Lake Erie-Lake Saint Clair Drainages, 1990-97

    USGS Publications Warehouse

    Rheaume, S.J.; Button, D.T.; Myers, D.N.; Hubbell, D.L.

    2001-01-01

    Concerns about elevated concentrations of contaminants such as polychlorinated biphenyls and mercury in aquatic bed sediments throughout the Great Lakes Basin have resulted in a need for better understanding of the scope and severity of the problem. Various organochlorine pesticides, polychlorinated biphenyls, trace metals, and polycyclic aromatic hydrocarbons are a concern because of their ability to persist and accumulate in aquatic sediments and their association with adverse aquatic biological effects. The areal distribution and concentrations in surficial bed sediments of 20 contaminants of concern with established bed-sediment-toxicity guidelines were examined in relation to their potential effects on freshwater aquatic biota. Contaminants at more than 800 sampling locations are characterized in this report. Surficial bed-sediment-quality data collected from 1990 to 1997 in the Lake Erie?Lake Saint Clair Drainages were evaluated to reflect recent conditions. In descending order, concentrations of total polycyclic aromatic hydrocarbons, phenanthrene, total polychlorinated biphenyls, chrysene, benz[a]anthracene, benzo[a]pyrene, cadmium, lead, zinc, arsenic, and mercury were the contaminants that most commonly exceeded levels associated with probable adverse effects on aquatic benthic organisms. The highest concentrations of most of these contaminants in aquatic bed sediments are confined to the 12 specific geographic Areas of Concern identified in the 1987 Revisions to the Great Lakes Water Quality Agreement of 1972. An exception is arsenic, which was detected at concentrations exceeding threshold effect levels at many locations outside Areas of Concern.

  12. Monitoring of polycyclic aromatic hydrocarbons in bees (Apis mellifera) and honey in urban areas and wildlife reserves.

    PubMed

    Perugini, Monia; Di Serafino, Gabriella; Giacomelli, Alessandra; Medrzycki, Piotr; Sabatini, Anna Gloria; Persano Oddo, Livia; Marinelli, Enzo; Amorena, Michele

    2009-08-26

    The honeybee is a good biological indicator that quickly reflects chemical impairment of the environment by its high mortality and the presence of pollutants in its body or in beehive products. In this work the honeybee (Apis mellifera) and honey were used to detect the presence of polycyclic aromatic hydrocarbons (PAHs) in several areas with different degrees of environmental pollution. All sampling sites showed the presence of PAHs. Benzo(a)pyrene was never detected. Fluorene, phenanthrene, anthracene, fluoranthene, benz(a)anthracene, benzo(b)fluoranthene, and benzo(k)fluoranthene were the PAHs detected in bees, whereas the honey contained only phenanthrene, anthracene, and chrysene. Phenanthrene showed the highest mean values in honeybees and honey. Independent from the season and location the pattern of PAHs in honeybees and honey was dominated by the presence of the lowest molecular weight PAHs. Furthermore, the mean PAH concentrations in honey samples were lower than those reported in honeybees, and no positive correlation was found between the compounds detected in bees and those in honey. PMID:19627114

  13. Characterization of wastes from construction and demolition sector.

    PubMed

    Somasundaram, Swarnalatha; Jeon, Tae-Wan; Kang, Young-Yeul; Kim, Woo-Il; Jeong, Seong-Kyeong; Kim, Yong-Jun; Yeon, Jin-Mo; Shin, Sun Kyoung

    2015-01-01

    In Republic of Korea, construction and demolition (C&D) waste accounts for 49.9% of the total waste. In the present work, the mineralogical composition, the concentrations of 11 heavy metals, 19 PAH, and 7 polychlorinated biphenyl (PCB) congeners present in the 6 broad category (9 subcategories) of C&D hazardous waste were discussed along with their leaching characteristics. In concrete/mixed cement waste, the concentrations of As, Cr(6+), Hg, and Zn were in the range of 1.76-7.86, ND-1.63, 0.026-0.047, and 110.90-280.17 mg/kg, respectively. The asphalt waste sample A1 possessed relatively high concentrations of phenanthrene, fluoranthene, pyrene, benz(a)anthracene, benzo(a)pyrene, and indeno(1,2,3-cd)pyrene comparing to the other samples and it contains 0.08-0.1% of coal tar. Hazardous nature of the C&D wastes greatly depends on the source of the collection. Zn concentration was above 1000 mg/kg for road asphalt waste samples A4 and A5. Total PCB concentration were high in the soil waste sample S1 (130 μg/kg) as it was the excavated soil obtained from the premises of an oil station. Leaching of As, Ba, CN(-), and F(-) were observed in most of the C&D waste samples. PMID:25504191

  14. Comparative analysis of the electrostatic potentials of some structural analogues of 2,3,7,8-tetrachlorodibenzo-p-dioxin and of related aromatic systems

    SciTech Connect

    Murray, J.S.; Evans, P.; Politzer, P.

    1990-01-01

    An ab initio STO-5G computational analysis of the electrostatic potentials of four structural analogs of the highly toxic 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and four related aromatic systems (benzo(a)pyrene, benz(a)anthracene and two isomeric benzoflavones) was carried out. The systems, to varying degrees, induce aryl hydrocarbon hydroxylase activity and are believed to interact with the same cytosolic receptor in initiating their biochemical responses. It was found that a high degree of activity appears to require negative potentials that are non-overlapping above all or most of the lateral regions, with an observed optimum range of magnitudes. In systems with central oxygens, it is required that the negative oxygen potentials be small and weak; however, oxygen negative regions in the molecule are not necessary for high activity. The observed differences between the potential patterns of the four aromatic systems and those of TCDD and its active analogs may reflect an inherent dissimilarity in the nature of their interactions with the cytosolic receptor.

  15. Seasonality and interspecies differences in particle/gas partitioning of PAHs observed by the Integrated Atmospheric Deposition Network (IADN)

    NASA Astrophysics Data System (ADS)

    Galarneau, Elisabeth; Bidleman, Terry F.; Blanchard, Pierrette

    This study presents partitioning data from eight locations in the Laurentian Great Lakes region collected by the Integrated Atmospheric Deposition Network (IADN) over periods ranging from 1 to 6 years. Particle/gas partitioning varies sufficiently between sites in the Great Lakes region to preclude the use of a uniform temperature dependence for its description. Site-specific parameters for describing partitioning as a function of inverse temperature are presented. Relationships between partitioning of appreciably semivolatile PAHs and saturated vapour pressure at Chicago (IIT) and Sturgeon Point (STP) demonstrate that anthracene, benz[a]anthracene and retene behave differently than phenanthrene, fluoranthene, pyrene and chrysene+triphenylene. Possible reasons for these differences include interspecies variations in the fraction of atmospherically non-exchangeable, though analytically extractable, PAHs on particles and differences in soot-air partition coefficients as they relate to saturated vapour pressure. The observed interspecies differences are not consistent with sampling artefacts such as filter adsorption or sorbent breakthrough. At IIT, but not at STP, values of the slope of the relationship between the log partition coefficient and log vapour pressure vary in a manner opposing the annual temperature cycle. A comparison of partitioning calculated by a combined absorption/adsorption model shows good predictability at Chicago but underestimates values at a rural site (Eagle Harbor, EGH) by an order of magnitude.

  16. Base sequence effects on interactions of aromatic mutagens with DNA: Progress report for period March 1, 1988--November 30, 1988

    SciTech Connect

    Geacintov, N.E.

    1988-12-01

    The influence of base sequence on the structure of DNA, and the relationships between these effects and gene expression and regulation, are currently receiving wide attention. This project is focused on the effects of base composition and sequence, as well as on the thermodynamics of the interactions and binding of polynuclear aromatic hydrocarbon (PAH) mutagens with DNA. Such interactions between PHA molecules and cellular DNA are believed to be of critical importance in the expression of the mutagenic and tumorigenic potentials of these compounds. We have studied the interactions, especially noncovalent complex formation between the tetraols derived by the hydrolysis of the bay region diol epoxides of benzo(a)pyrene (BP), benz(a)anthracene (BA), 7,12-dimethylbenz(a)anthracene (DMBA), and 3-methylcholanthrene (3-MC) with single nucleotides, dinucleotides, oligonucleotides, synthetic polynucleotides, and native DNA. The formation of physical complexes depends on the base composition and the base sequence. The differences in the physical binding of these three different tetraol derivatives to native DNA are due to entropic rather than to enthalpic effects. In contrast to the BP and BA tetraols, the 3-MC tetraols do not form intercalation complexes with DNA; this effect is attributed to the steric bulk of the methyl and methylene bridge group which prevents the sandwiching of the 3-MC tetraol between the DNA base pairs. 6 refs., 3 figs., 2 tabs.

  17. Influence of retinol on carcinogen-induced sister chromatid exchangers and chromosome aberrations in V79 cells

    SciTech Connect

    Qin, S.; Batt, T.; Huang, C.C.

    1985-01-01

    The influence of retinol (Rol) on sister chromatid exchangers (SCE) in V79 cells induced by six indirect and two direct carcinogens, and on chromosome aberration (CA) in V79 cells induced by four indirect carcinogens were studied. The indirect carcinogens used were aflatoxin B/sub 1/ (AFB), cyclophosphamide (CPP), benzo(a)anthracene (BA), benzo(a)pyrene (BP), 9,10-dimethyl-1,2-benz(a)anthracene (DMBA), and 3-methylcholanthrene (MCA). The two direct carcinogens were ethyl methane sulfonate (EMS) and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Rol effectively inhibited SCE and CA induced by AFB and CPP in a dose-dependent manner, but it had no effect on SCE induced by BA, BP, DMBA, MCA, EMS, and MNNG. To the contrary, Rol had an enhancing effect on CA induced by BP and DMBA. The possibility that Rol exerts its anticarcinogenic effects by inhibiting certain forms of the cytochrome P-450 isoenzymes required for activation of precarcinogens, such as AFB and CPP but not those enzymes required by BA, BP, DMBA, and MCA, is discussed.

  18. Alkyl substitution effects on the intercalation of carcinogenic hydrocarbon and hydrocarbon metabolites into DNA

    SciTech Connect

    LeBreton, P.R.

    1986-05-01

    A large number of carcinogenic hydrocarbons and hydrocarbon metabolites intercalate into DNA with binding constants in terms of PO/sub 4//sup -/ concentration which lie in the range 10/sup 3/-10/sup 4/ M/sup -1/. These binding constants are similar to those associated with base stacking and hydrogen bonding interactions that occur naturally in DNA. Previous studies show that different metabolites derived from the same parent hydrocarbon exhibit different binding properties. In recent studies the authors have examined the effects of alkyl substitution on hydrocarbon binding to calf thymus DNA. Such groups can enhance or inhibit carcinogenic activity. Studies of 1-alkyl BP/sup +/ derivatives and of their 7,8-dihydrodiols indicate that the alkyl groups ethyl, isopropyl and t-butyl inhibit intercalation. Methyl groups can either inhibit or enhance intercalation into DNA. The binding constants of DMBA and BA are nearly the same. However, DMA, which is a ..pi.. electron model compound of the bay region diol epoxide of DMBA, binds 6.7 times better than anthracene. Similarly, highly carcinogenic 5-methylchyrsene binds to DNA 3.9 times better than chrysene. /sup +/Abbreviations: BP, benzo(a)pyrene; DMBA, 7,12-dimethylbenz(a)anthracene; BA, benz(a)anthracene DMA, 9,10-dimethylanthracene.

  19. Proposal for a screening test to evaluate the fate of organic micropollutants in activated sludge.

    PubMed

    Salvetti, Roberta; Vismara, Renato; Dal Ben, Ilaria; Gorla, Elena; Romele, Laura

    2011-04-01

    The concentrations of organic micropollutants are usually low in wastewaters (order of magnitude of mg L(-1)). However, their emission standards, especially in the case of carcinogenic and bioaccumulating substances, are often much lower (order of magnitude of microg L(-1)). Since these substances, in some cases, can be adsorbable or volatile, their removal via volatilization, biodegradation or sludge adsorption in a wastewater treatment plant (WWTP) becomes a significant feature to include in the usual design process, in order to verify the emission standards in gas and sludge too. In this study a simple screening batch test for the evaluation of the fate of organic micropollutants in water, air and sludge is presented. The test is set up by means of simple laboratory instruments and simulates an activated sludge tank process. In this study the results obtained for four substances with different chemical properties (i.e. toluene, benz(a)anthracene, phenol and benzene) are presented. The screening test proposed can be a useful tool to assess in about one month the fate of organic micropollutants in an activated sludge tank of a WWTP. Moreover, the test can constitute a useful support in the use of mathematical models, since it allows the verification of model results and the calibration of the reactions involved in the removal process. PMID:21877546

  20. A simple methodological validation of the gas/particle fractionation of polycyclic aromatic hydrocarbons in ambient air

    PubMed Central

    Kim, Yong-Hyun; Kim, Ki-Hyun

    2015-01-01

    The analysis of polycyclic aromatic hydrocarbons (PAH) in ambient air requires the tedious experimental steps of both sampling and pretreatment (e.g., extraction or clean-up). To replace pre-existing conventional methods, a simple, rapid, and novel technique was developed to measure gas-particle fractionation of PAH in ambient air based on ‘sorbent tube-thermal desorption-gas chromatograph-mass spectrometer (ST-TD-GC-MS)’. The separate collection and analysis of ambient PAHs were achieved independently by two serially connected STs. The basic quality assurance confirmed good linearity, precision, and high sensitivity to eliminate the need for complicated pretreatment procedures with the detection limit (16 PAHs: 13.1 ± 7.04 pg). The analysis of real ambient PAH samples showed a clear fractionation between gas (two-three ringed PAHs) and particulate phases (five-six ringed PAHs). In contrast, for intermediate (four ringed) PAHs (fluoranthene, pyrene, benz[a]anthracene, and chrysene), a highly systematic/gradual fractionation was established. It thus suggests a promising role of ST-TD-GC-MS as measurement system in acquiring a reliable database of airborne PAH. PMID:26126962

  1. Quantitative determination of hydroxy polycylic aromatic hydrocarbons as a biomarker of exposure to carcinogenic polycyclic aromatic hydrocarbons.

    PubMed

    Woudneh, Million B; Benskin, Jonathan P; Grace, Richard; Hamilton, M Coreen; Magee, Brian H; Hoeger, Glenn C; Forsberg, Norman D; Cosgrove, John R

    2016-07-01

    A high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS) method was developed for quantitative analysis of hydroxy polycyclic aromatic hydrocarbons (OH-PAHs). Four hydroxy metabolites of known and suspected carcinogenic PAHs (benzo[a]pyrene (B[a]P), benz[a]anthracene (B[a]A), and chrysene (CRY)) were selected as suitable biomarkers of PAH exposure and associated risks to human health. The analytical method included enzymatic deconjugation, liquid - liquid extraction, followed by derivatization with methyl-N-(trimethylsilyl) trifluoroacetamide and instrumental analysis. Photo-induced oxidation of target analytes - which has plagued previously published methods - was controlled by a combination of minimizing exposure to light, employing an antioxidant (2-mercaptoethanol) and utilizing a nitrogen atmosphere. Stability investigations also indicated that conjugated forms of the analytes are more stable than the non-conjugated forms. Accuracy and precision of the method were 77.4-101% (<4.9% RSD) in synthetic urine and 92.3-117% (<15% RSD) in human urine, respectively. Method detection limits, determined using eight replicates of low-level spiked human urine, ranged from 13 to 24pg/mL. The method was successfully applied for analysis of a pooled human urine sample and 78 mouse urine samples collected from mice fed with PAH-contaminated diets. In mouse urine, greater than 94% of each analyte was present in its conjugated form. PMID:27266337

  2. Evaluation of low-dosage environmental mutagens with a long-term, cultured epithelial cell line

    SciTech Connect

    Li, C.S.; Lin, R.H.

    1996-12-31

    Polycyclic or polynuclear aromatic hydrocarbons (PAHs) are a group of compounds consisting of at least two fused aromatic rings and are common environmental contaminants in soil, water, and air. Additionally, some PAHs are considered to be mutagenic, carcinogenic, and cytotoxic compounds. BaA (Benz(a)anthracene) and BaP (Benzo(a)pyrene) are the two major unsubstituted PAHs identified by the USEPA as priority pollutants. BaA is suspected to be a human carcinogen by the US Department of Health and Human Services, whereas BaP is regarded as an animal carcinogen. It is estimated that the emission concentrations of BaA and BaP from mainstream cigarette smoke are 20-70 ng per g cigarette and 20-40 ng per g cigarette, respectively, with an average sidestream to mainstream weight ratio of 3. In addition, BaA and BaP are also the main emissions from diesel particulate extracts with mean concentrations of 500 ppm and 40 ppm, respectively. From a recent report concerning PAHs in urban areas all over the world, the airborne concentration of BaP was typically found to be in the range of 1-20 ng/m{sup 3} in Europe and 1 ng/m{sup 3} in the U.S.A. For BaA, the concentrations commonly ranged from I to 50 ng/m{sup 3} in Europe and from 0.1 to 1 ng/m{sup 3} in the U.S.A. Therefore, the long term exposure to these two compounds may cause health effects. This study examines long-term cultured epithelial cell lines exposed to BaP or BaA, in vitro, and the frequency of HGPRT mutants. 19 refs., 3 figs.

  3. Characterization of Pseudomonas monteilii CCM 3423 and its physiological potential for biodegradation of selected organic pollutants.

    PubMed

    Vojtková, Hana; Kosina, Marcel; Sedláček, Ivo; Mašlaňová, Ivana; Harwotová, Markéta; Molinková, Veronika

    2015-09-01

    Pseudomonas monteilii CCM 3423 bacterial strain, deposited at the Czech Collection of Microorganisms, was originally isolated by Haľama and Augustín (1980) as a bacterium degrading aromatic hydrocarbons and derivates. A detailed study supported by a molecular genetics method of sequence analyses of rrs and rpoD genes was used to reclassify the strain, originally stored as 'Pseudomonas putida'. The physiological characteristics of the strain are complemented with research in the capacity to utilize selected organic pollutants (anthracene, benz[a]anthracene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, fluorene, naphthalene, phenanthrene). The obtained results point at very good biodegradation properties of the strain. Already after 7 days of the bacterial strain's action, there was a decrease in all the organic contaminants to 79.8 ± 2.6 %. In 14 days, the amount of organic contaminants dropped to 59.3 ± 2.8 %. After 21 days of biodegradation experiments, the overall quantity of the observed organic substances fell below the half limit to 45.7 ± 2.5 % of residuals. Finally, after 28 days, the residue was 35.4 ± 2.2 %, and after 35 days of the action of P. monteilii, the tested samples contained mere 27.8 ± 2.8 % of organic pollutants. The results imply that Pseudomonas monteilii CCM 3423 is a prospective strain in terms of further biotechnological application in contaminated environment. PMID:25543262

  4. Structurally distinct polycyclic aromatic hydrocarbons induce differential transcriptional responses in developing zebrafish

    PubMed Central

    Goodale, Britton C.; Tilton, Susan C.; Wilson, Glenn; Corvi, Margaret M.; Janszen, Derek B.; Anderson, Kim A.; Waters, Katrina M.; Tanguay, Robert L.

    2014-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the environment as components of fossil fuels and by-products of combustion. These multi-ring chemicals differentially activate the Aryl Hydrocarbon Receptor (AHR) in a structurally dependent manner, and induce toxicity via both AHR-dependent and-independent mechanisms. PAH exposure is known to induce developmental malformations in zebrafish embryos, and recent studies have shown cardiac toxicity induced by compounds with low AHR affinity. Unraveling the potentially diverse molecular mechanisms of PAH toxicity is essential for understanding the hazard posed by complex PAH mixtures present in the environment. We analyzed transcriptional responses to PAH exposure in zebrafish embryos exposed to benz(a)anthracene (BAA), dibenzothiophene (DBT) and pyrene (PYR) at concentrations that induced developmental malformations by 120 hours post-fertilization (hpf). Whole genome microarray analysis of mRNA expression at 24 and 48 hpf identified genes that were differentially regulated over time and in response to the three PAH structures. PAH body burdens were analyzed at both time points using GC-MS, and demonstrated differences in PAH uptake into the embryos. This was important for discerning dose-related differences from those that represented unique molecular mechanisms. While BAA misregulated the least number of transcripts, it caused strong induction of cyp1a and other genes known to be downstream of the AHR, which were not induced by the other two PAHs. Analysis of functional roles of misregulated genes and their predicted regulatory transcription factors also distinguished the BAA response from regulatory networks disrupted by DBT and PYR exposure. These results indicate that systems approaches can be used to classify the toxicity of PAHs based on the networks perturbed following exposure, and may provide a path for unraveling the toxicity of complex PAH mixtures. PMID:23656968

  5. Atmospheric behaviors of polycyclic aromatic hydrocarbons at a Japanese remote background site, Noto peninsula, from 2004 to 2014

    NASA Astrophysics Data System (ADS)

    Tang, Ning; Hakamata, Mariko; Sato, Kousuke; Okada, Yumi; Yang, Xiaoyang; Tatematsu, Michiya; Toriba, Akira; Kameda, Takayuki; Hayakawa, Kazuichi

    2015-11-01

    Total suspended particulates were collected at a Japanese remote background site (Noto Air Monitoring Station; NAMS) on the Noto Peninsula from September 2004 to June 2014. Nine polycyclic aromatic hydrocarbons (PAHs) in the particulates (fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, benzo[ghi]perylene and indeno[1,2,3-cd]pyrene) were determined by HPLC with fluorescence detection. The mean total concentrations of the nine PAHs in the cold season (November to May for the years 2004-2014) was 670 pg m-3 (range 37-4100 pg m-3). The mean total concentration in the warm season (June to October for the same period) was 170 pg m-3 (range 31-960 pg m-3). The atmospheric PAH level at NAMS decreased in recent years, although no significant change was found in the warm season. An analysis of meteorological conditions showed that the atmospheric PAHs at NAMS were long range transported from Northeast China in the cold seasons and were contributed to by Japanese domestic sources in the warm seasons. Lower concentration ratios of reactive PAHs to their isomers at NAMS also supported these results. Activities associated with the Beijing Olympic and Paralympic Games in 2008 and reconstruction after the 2007 Noto Hanto earthquake may have contributed to the yearly variations of atmospheric PAH levels at NAMS during the period 2007-2009. Source control measures implemented by the Chinese and Japanese governments appear to have been effective in decreasing the atmospheric PAH levels at NAMS in recent years.

  6. Occurrence, sources and health risk assessment of polycyclic aromatic hydrocarbons in urban (Pudong) and suburban soils from Shanghai in China.

    PubMed

    Wang, Xue-Tong; Chen, Lei; Wang, Xi-Kui; Lei, Bing-Li; Sun, Yan-Feng; Zhou, Jun; Wu, Ming-Hong

    2015-01-01

    A comprehensive investigation was conducted to the urban (Pudong) and suburban soils in Shanghai. A total of 154 soil samples were analyzed for 26 PAHs including highly carcinogenic dibenzopyrenes (DBPs). The total concentrations ranged from 25.8 to 7380 μg kg(-1) for Σ26PAHs and 18.8 to 6320 μg kg(-1) for 16 USEPA priority PAHs (Σ16PAHs), respectively. The BaP toxic equivalent (BaPeq) concentrations were between 6.41 and 2880 μg kg(-1) for Σ24PAHs, 1.11 and 620 μg kg(-1) for Σ16PAHs and 2.72 and 2250 μg kg(-1) for Σ4DBPs. The high PAH contamination in green land soils might originate mainly from local road traffic and industrial activities, and sewage sludge application or waste water irrigation for soil. Seven sources of soil PAHs in Shanghai were identified by positive matrix factorization (PMF) model. The mean risk quotient (m-RQ) values indicated that there were medium to high ecological risks in 9.10% of soil samples, pyrene (Pyr), benzo[b]fluoranthene (BbF) and benz[a]anthracene (BaA) were the major ecological risk drivers under agricultural use. The cancer risk (CR) values were within the acceptable range at 35.7%, 35.1% and 31.2% of sampling sites for children, youths and adults, respectively. The total lifetime carcinogenic risk (TLCR) values at 57.8% of sampling sites were within the acceptable range. Overall, cancer risks of soil PAHs in all sampling sites in the studied area were below the highest acceptable risk, suggesting that soil PAHs are unlikely to pose a significant cancer risk for population based on ingestion, dermal contact and inhalation exposure pathways. PMID:25460765

  7. Ligand-specific transcriptional mechanisms underlie aryl hydrocarbon receptor-mediated developmental toxicity of oxygenated PAHs

    SciTech Connect

    Goodale, B. C.; La Du, J.; Tilton, S. C.; Sullivan, C. M.; Bisson, W. H.; Waters, K. M.; Tanguay, R. L.

    2015-07-03

    Polycyclic aromatic hydrocarbons (PAHs) are priority environmental contaminants that exhibit mutagenic, carcinogenic, proinflammatory, and teratogenic properties. Oxygen-substituted PAHs (OPAHs) are formed during combustion processes and via phototoxidation and biological degradation of parent (unsubstituted) PAHs. Despite their prevalence both in contaminated industrial sites and in urban air, OPAH mechanisms of action in biological systems are relatively understudied. Like parent PAHs, OPAHs exert structure-dependent mutagenic activities and activation of the aryl hydrocarbon receptor (AHR) and cytochrome p450 metabolic pathway. Four-ring OPAHs 1,9-benz-10-anthrone (BEZO) and benz(a)anthracene-7,12-dione (7,12-B[a]AQ) cause morphological aberrations and induce markers of oxidative stress in developing zebrafish with similar potency, but only 7,12-B[a]AQ induces robust Cyp1a protein expression. We investigated the role of the AHR in mediating the toxicity of BEZO and 7,12-B[a]AQ, and found that knockdown of AHR2 rescued developmental effects caused by both compounds. Using RNA-seq and molecular docking, we identified transcriptional responses that precede developmental toxicity induced via differential interaction with AHR2. Redox-homeostasis genes were affected similarly by these OPAHs, while 7,12-B[a]AQ preferentially activated phase 1 metabolism and BEZO uniquely decreased visual system genes. Analysis of biological functions and upstream regulators suggests that BEZO is a weak AHR agonist, but interacts with other transcriptional regulators to cause developmental toxicity in an AHR-dependent manner. Furthermore, identifying ligand-dependent AHR interactions and signaling pathways is essential for understanding toxicity of this class of environmentally relevant compounds.

  8. Ligand-specific transcriptional mechanisms underlie aryl hydrocarbon receptor-mediated developmental toxicity of oxygenated PAHs

    DOE PAGESBeta

    Goodale, B. C.; Geisel School of Medicine at Dartmouth, Hanover, NH; La Du, J.; Tilton, S. C.; Pacific Northwest National Lab.; Sullivan, C. M.; Bisson, W. H.; Waters, K. M.; Tanguay, R. L.

    2015-07-03

    Polycyclic aromatic hydrocarbons (PAHs) are priority environmental contaminants that exhibit mutagenic, carcinogenic, proinflammatory, and teratogenic properties. Oxygen-substituted PAHs (OPAHs) are formed during combustion processes and via phototoxidation and biological degradation of parent (unsubstituted) PAHs. Despite their prevalence both in contaminated industrial sites and in urban air, OPAH mechanisms of action in biological systems are relatively understudied. Like parent PAHs, OPAHs exert structure-dependent mutagenic activities and activation of the aryl hydrocarbon receptor (AHR) and cytochrome p450 metabolic pathway. Four-ring OPAHs 1,9-benz-10-anthrone (BEZO) and benz(a)anthracene-7,12-dione (7,12-B[a]AQ) cause morphological aberrations and induce markers of oxidative stress in developing zebrafish with similar potency, butmore » only 7,12-B[a]AQ induces robust Cyp1a protein expression. We investigated the role of the AHR in mediating the toxicity of BEZO and 7,12-B[a]AQ, and found that knockdown of AHR2 rescued developmental effects caused by both compounds. Using RNA-seq and molecular docking, we identified transcriptional responses that precede developmental toxicity induced via differential interaction with AHR2. Redox-homeostasis genes were affected similarly by these OPAHs, while 7,12-B[a]AQ preferentially activated phase 1 metabolism and BEZO uniquely decreased visual system genes. Analysis of biological functions and upstream regulators suggests that BEZO is a weak AHR agonist, but interacts with other transcriptional regulators to cause developmental toxicity in an AHR-dependent manner. Furthermore, identifying ligand-dependent AHR interactions and signaling pathways is essential for understanding toxicity of this class of environmentally relevant compounds.« less

  9. Chemopreventive efficacy of naringenin-loaded nanoparticles in 7,12-dimethylbenz(a)anthracene induced experimental oral carcinogenesis.

    PubMed

    Sulfikkarali, Nechikkad; Krishnakumar, Narendran; Manoharan, Shanmugam; Nirmal, Ramadas Madhavan

    2013-04-01

    Nanochemoprevention has been introduced recently as a novel approach for improving phytochemicals bioavailability and anti-tumor effect. The present study is designed to evaluate the chemopreventive efficacy of prepared naringenin-loaded nanoparticles (NARNPs) relative to efficacy of free naringenin (NAR) against 7,12-dimethyl benz(a)anthracene (DMBA)-induced oral carcinogenesis by evaluating the status of lipid peroxidation, antioxidants and immunoexpression patterns of proliferating cell nuclear antigen (PCNA) and p53 proteins. Transmission electron microscope (TEM) and dynamic light scattering (DLS) investigations have confirmed a narrow size distribution of the prepared nanoparticles (40-90 nm) with ~88 % encapsulation efficiency. Oral squamous cell carcinoma (OSCC) was developed in the buccal pouch of golden Syrian hamsters by painting with 0.5 % DMBA in liquid paraffin three times a week for 14 weeks. DMBA painted animals revealed the morphological changes, hyperplasia, dysplasia and well-differentiated squamous cell carcinoma. Moreover, the status of lipid peroxidation, antioxidants and immunoexpression of PCNA and p53 were significantly altered during DMBA-induced oral carcinogenesis. Oral administration of NARNPs (50 mg NAR/kg body weight/day) to DMBA-treated animals completely prevented the tumor formation as compared to the free NAR and significantly reduced the degree of histological lesions, in addition to restoration of the status of biochemical and molecular markers during oral carcinogenesis. In addition, NARNPs have more potent anti-lipid peroxidative, antiproliferative effect and antioxidant potentials compared to free NAR in DMBA-induced oral carcinogenesis. In conclusion, the present study suggests that NARNPs could be a potentially useful drug carrier system for targeted delivery of naringenin for cancer chemoprevention. PMID:23233294

  10. Raman spectroscopy detects biomolecular changes associated with nanoencapsulated hesperetin treatment in experimental oral carcinogenesis

    NASA Astrophysics Data System (ADS)

    Gurushankar, K.; Gohulkumar, M.; Kumar, Piyush; Krishna, C. Murali; Krishnakumar, N.

    2016-03-01

    Recently it has been shown that Raman spectroscopy possesses great potential in the investigation of biomolecular changes of tumor tissues with therapeutic drug response in a non-invasive and label-free manner. The present study is designed to investigate the antitumor effect of hespertin-loaded nanoparticles (HETNPs) relative to the efficacy of native hesperetin (HET) in modifying the biomolecular changes during 7,12-dimethyl benz(a)anthracene (DMBA)-induced oral carcinogenesis using a Raman spectroscopic technique. Significant differences in the intensity and shape of the Raman spectra between the control and the experimental tissues at 1800-500 cm-1 were observed. Tumor tissues are characterized by an increase in the relative amount of proteins, nucleic acids, tryptophan and phenylalanine and a decrease in the percentage of lipids when compared to the control tissues. Further, oral administration of HET and its nanoparticulates restored the status of the lipids and significantly decreased the levels of protein and nucleic acid content. Treatment with HETNPs showed a more potent antitumor effect than treatment with native HET, which resulted in an overall reduction in the intensity of several biochemical Raman bands in DMBA-induced oral carcinogenesis being observed. Principal component and linear discriminant analysis (PC-LDA), together with leave-one-out cross validation (LOOCV) on Raman spectra yielded diagnostic sensitivities of 100%, 80%, 91.6% and 65% and specificities of 100%, 65%, 60% and 55% for classification of control versus DMBA, DMBA versus DMBA  +  HET, DMBA versus DMBA  +  HETNPs and DMBA  +  HET versus DMBA  +  HETNPs treated tissue groups, respectively. These results further demonstrate that Raman spectroscopy associated with multivariate statistical algorithms could be a valuable tool for developing a comprehensive understanding of the process of biomolecular changes, and could reveal the signatures of the

  11. Quantification of carcinogenic 4- to 6-ring polycyclic aromatic hydrocarbons in human urine by solid-phase microextraction gas chromatography-isotope dilution mass spectrometry.

    PubMed

    Campo, Laura; Fustinoni, Silvia; Bertazzi, Pieralberto

    2011-08-01

    Polycyclic aromatic hydrocarbons (PAHs) are pollutants found in living and working environments. The aim of this study was to develop a solid-phase microextraction (SPME) gas chromatography (GC)-isotope dilution mass spectrometry method for the quantification of 10 four- to six-ring PAHs in urine samples. Seven of the selected PAHs have been classified as carcinogenic. Under the final conditions, analytes were sampled with a 100-μm polydimethylsiloxane SPME fibre for 60 min at 80 °C and desorbed in the injection port of the GC at 270 °C. Fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenzo[a,h]anthracene, indeno[1,2,3-cd]pyrene and benzo[ghi]perylene were separated using a highly arylene-modified phase capillary column and quantified by MS using eight deuterated PAHs as surrogate internal standards. Limits of quantification (LOQ) were in the 0.5- to 2.2-ng/L range. Validation showed linear dynamic ranges up to 340 ng/L, inter- and intra-run precisions <20%, and accuracies within 20% of spiked concentrations. Matrix effect evaluation and the use of control charts to monitor process performances showed that the isotope dilution approach allowed for the control of bias sources. Urinary PAHs were above or equal to LOQ, depending on different compounds, in 58-100% (min-max), 40-100% and 5-39% of samples from coke oven workers (n = 12), asphalt workers (n = 10) and individuals not occupationally exposed to PAHs (n = 18), respectively. Chrysene was the most abundant PAH determined with median levels of 62.6, 6.9 and <0.6 ng/L, respectively. These results show that the method is suitable for quantifying carcinogenic PAHs in specimens from individuals with different levels of PAH exposure. PMID:21626187

  12. Aquatic predicted no-effect concentrations of 16 polycyclic aromatic hydrocarbons and their ecological risks in surface seawater of Liaodong Bay, China.

    PubMed

    Wang, Ying; Wang, Juying; Mu, Jingli; Wang, Zhen; Cong, Yi; Yao, Ziwei; Lin, Zhongsheng

    2016-06-01

    Polycyclic aromatic hydrocarbons (PAHs), a class of ubiquitous pollutants in marine environments, exhibit moderate to high adverse effects on aquatic organisms and humans. However, the lack of PAH toxicity data for aquatic organism has limited evaluation of their ecological risks. In the present study, aquatic predicted no-effect concentrations (PNECs) of 16 priority PAHs were derived based on species sensitivity distribution models, and their probabilistic ecological risks in seawater of Liaodong Bay, Bohai Sea, China, were assessed. A quantitative structure-activity relationship method was adopted to achieve the predicted chronic toxicity data for the PNEC derivation. Good agreement for aquatic PNECs of 8 PAHs based on predicted and experimental chronic toxicity data was observed (R(2)  = 0.746), and the calculated PNECs ranged from 0.011 µg/L to 205.3 µg/L. A significant log-linear relationship also existed between the octanol-water partition coefficient and PNECs derived from experimental toxicity data (R(2)  = 0.757). A similar order of ecological risks for the 16 PAH species in seawater of Liaodong Bay was found by probabilistic risk quotient and joint probability curve methods. The individual high ecological risk of benzo[a]pyrene, benzo[b]fluoranthene, and benz[a]anthracene needs to be determined. The combined ecological risk of PAHs in seawater of Liaodong Bay calculated by the joint probability curve method was 13.9%, indicating a high risk as a result of co-exposure to PAHs. Environ Toxicol Chem 2016;35:1587-1593. © 2015 SETAC. PMID:26517571

  13. 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 PAHs (ΣPAHs) 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

  14. Single-laboratory validation of a saponification method for the determination of four polycyclic aromatic hydrocarbons in edible oils by HPLC-fluorescence detection.

    PubMed

    Akdoğan, Abdullah; Buttinger, Gerhard; Wenzl, Thomas

    2016-01-01

    An analytical method is reported for the determination of four polycyclic aromatic hydrocarbons (benzo[a]pyrene (BaP), benz[a]anthracene (BaA), benzo[b]fluoranthene (BbF) and chrysene (CHR)) in edible oils (sesame, maize, sunflower and olive oil) by high-performance liquid chromatography. Sample preparation is based on three steps including saponification, liquid-liquid partitioning and, finally, clean-up by solid phase extraction on 2 g of silica. Guidance on single-laboratory validation of the proposed analysis method was taken from the second edition of the Eurachem guide on method validation. The lower level of the working range of the method was determined by the limits of quantification of the individual analytes, and the upper level was equal to 5.0 µg kg(-1). The limits of detection and quantification of the four PAHs ranged from 0.06 to 0.12 µg kg(-1) and from 0.13 to 0.24 µg kg(-1). Recoveries of more than 84.8% were achieved for all four PAHs at two concentration levels (2.5 and 5.0 µg kg(-1)), and expanded relative measurement uncertainties were below 20%. The performance of the validated method was in all aspects compliant with provisions set in European Union legislation for the performance of analytical methods employed in the official control of food. The applicability of the method to routine samples was evaluated based on a limited number of commercial edible oil samples. PMID:26634339

  15. Identification of a novel Calotropis procera protein that can suppress tumor growth in breast cancer through the suppression of NF-κB pathway.

    PubMed

    Samy, Ramar Perumal; Rajendran, Peramaiyan; Li, Feng; Anandi, Narayana Moorthy; Stiles, Bradley G; Ignacimuthu, Savarimuthu; Sethi, Gautam; Chow, Vincent T K

    2012-01-01

    Breast cancer is the most common cancer among women. To date, improvements in hormonal and cytotoxic therapies have not yet led to a sustained remission or cure. In the present study, we investigated the in vitro and in vivo antitumor activities of a novel Calotropis procera protein (CP-P) isolated from root bark. CP-P protein inhibited the proliferation and induced apoptosis of breast cancer cells through the suppression of nuclear factor kappaB (NF-kB) activation. CP-P, when administered individually or in combination with cyclophosphamide (CYC, 0.2 mg/kg) to rats with 7, 12-dimethyl benz(a)anthracene (DMBA)-induced breast cancer decreased tumor volume significantly without affecting the body weight. To elucidate the anticancer mechanism of CP-P, antioxidant activities such as superoxide dismutase (SOD), catalase (CAT), glutathione-s-transferase (GST) and non-enzymatic antioxidant - reduced glutathione (GSH), vitamin E and C generation in the breast were analyzed by various assays. SOD, CAT, GST, GSH, vitamin E and C levels were high in combination-treated groups (CP-P+CYC) versus the CYC alone-treated groups. Also, the combination was more effective in down-regulating the expression of NF-kB-regulated gene products (cyclin D1 and Bcl-2) in breast tumor tissues. Our findings indicate that CP-P possesses significant antitumor activity comparable to a commonly used anticancer drug, cyclophosphamide, and may form the basis of a novel therapy for breast cancer. PMID:23284617

  16. Developmental toxicity of 4-ring polycyclic aromatic hydrocarbons in zebrafish is differentially dependent on AH receptor isoforms and hepatic cytochrome P4501A metabolism

    SciTech Connect

    Incardona, John P. . E-mail: john.incardona@noaa.gov; Day, Heather L.; Collier, Tracy K.; Scholz, Nathaniel L.

    2006-12-15

    Polycyclic aromatic hydrocarbons (PAHs) derived from fossil fuels are ubiquitous contaminants and occur in aquatic habitats as highly variable and complex mixtures of compounds containing 2 to 6 rings. For aquatic species, PAHs are generally accepted as acting through either of two modes of action: (1) 'dioxin-like' toxicity mediated by activation of the aryl hydrocarbon receptor (AHR), which controls a battery of genes involved in PAH metabolism, such as cytochrome P4501A (CYP1A) and (2) 'nonpolar narcosis', in which tissue uptake is dependent solely on hydrophobicity and toxicity is mediated through non-specific partitioning into lipid bilayers. As part of a systematic analysis of mechanisms of PAH developmental toxicity in zebrafish, we show here that three tetracyclic PAHs (pyrene, chrysene, and benz[a]anthracene) activate the AHR pathway tissue-specifically to induce distinct patterns of CYP1A expression. Using morpholino knockdown of ahr1a, ahr2, and cyp1a, we show that distinct embryolarval syndromes induced by exposure to two of these compounds are differentially dependent on tissue-specific activation of AHR isoforms or metabolism by CYP1A. Exposure of embryos with and without circulation (silent heart morphants) resulted in dramatically different patterns of CYP1A induction, with circulation required to deliver some compounds to internal tissues. Therefore, biological effects of PAHs cannot be predicted simply by quantitative measures of AHR activity or a compound's hydrophobicity. These results indicate that current models of PAH toxicity in fish are greatly oversimplified and that individual PAHs are pharmacologically active compounds with distinct and specific cellular targets.

  17. Airborne exposures to PAH and PM2.5 particles for road paving workers applying conventional asphalt and crumb rubber modified asphalt.

    PubMed

    Watts, R R; Wallingford, K M; Williams, R W; House, D E; Lewtas, J

    1998-01-01

    Personal exposure monitoring was conducted for road paving workers in three states. A research objective was to characterize and compare occupational exposures to fine respirable particles (< 2.5 microns) and particle-bound polycyclic aromatic hydrocarbons (PAHs) for road paving workers applying conventional (petroleum derived) asphalt and asphalt containing crumb rubber from shredded tires. Workers not exposed to asphalt fume were also included for comparison (to support the biomarker component of this study). The rubber content of the crumb rubber modified (CRM) asphalt at the three study sites was 12, 15, and 20%. A comparison of some specific job categories from two sites indicates greater potential carcinogenic PAH exposures during CRM asphalt work, however, the site with the greatest overall exposures did not indicate any differences for specific jobs. A statistical analysis of means for fine particle, pyrene and total carcinogenic PAH personal exposure shows, with two exceptions, there were no differences in exposures for these three measurement variables. One site shows significantly elevated pyrene exposure for CRM asphalt workers and another site similarly shows greater carcinogenic PAH exposure for CRM asphalt workers. Conventional and CRM asphalt worker airborne exposures to the PAH carcinogen marker, BaP, were very low with concentrations comparable to ambient air in many cities. However, this study demonstrates that asphalt road paving workers are exposed to elevated airborne concentrations of a group of unknown compounds that likely consist of the carcinogenic PAHs benz(a)anthracene, chrysene and methylated derivatives of both. The research described in this article has been reviewed in accordance with U.S. Environmental Protection Agency policy and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use. PMID:9577752

  18. Hard Cap Espresso Machines in Analytical Chemistry: What Else?

    PubMed

    Armenta, Sergio; de la Guardia, Miguel; Esteve-Turrillas, Francesc A

    2016-06-21

    A hard cap espresso machine has been used in combination with liquid chromatography with molecular fluorescence detection for the determination of polycyclic aromatic hydrocarbons (PAHs) from contaminated soils and sediments providing appropriate extraction efficiencies and quantitative results. Naphthalene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benz[a]anthracene, chrysene, benz[b]fluoranthene, benz[k]fluoranthene, benz[a]pyrene, dibenz[a,h]anthracene, benz[ghi]perylene, and indeno[1,2,3-cd]pyrene were used as target compounds. It should be mentioned that the pairs benz[a]anthracene-chrysene and dibenz[a,h]anthracene-benz[ghi]perylene peaks coelute under the employed chromatographic conditions; thus, those compounds were determined together. PAHs were extracted from 5.0 g of soil, previously homogenized, freeze-dried, and sieved to 250 μm, with 50 mL of 40% (v/v) acetonitrile in water at a temperature of 72 ± 3 °C. The proposed procedure is really fast, with an extraction time of 11 s, and it reduces the required amount of organic solvent to do the sample preparation. The obtained limit of detection for the evaluated PAHs was from 1 to 38 μg kg(-1). Recoveries were calculated using clean soils spiked with 100, 500, 1000, and 2000 μg kg(-1) PAHs with values ranging from 81 to 121% and good precision with relative standard deviation values lower than 30%. The method was validated using soil and sediment certified reference materials and also using real samples by comparison with ultrasound-assisted extraction, as reference methodology, obtaining statistically comparable results. Thus, the use of hard cap espresso machines in the analytical laboratories offers tremendous possibilities as low cost extraction units for the extraction of solid samples. PMID:27224000

  19. Elimination of deleterious effects of DMBA-induced skin carcinogenesis in mice by Syzygium cumini seed extract.

    PubMed

    Parmar, Jyoti; Sharma, Priyanka; Verma, Preeti; Sharma, Priyanka; Goyal, Pradeep K

    2011-09-01

    The inhibition of tumor incidence by hydro-alcoholic extract of S.cumini seed was evaluated in mice on two stage process of skin carcinogenesis induced by single application of 7, 12-dimethyl benz(a)anthracene (100 µg/100µl of acetone), and 2 weeks later promoted by repeated application of croton oil (1% acetone/thrice in a week) till the end of the experiment (i.e. 16 weeks). Oral administration of extract at a dose of 250mg/kg b.wt./day at the peri-initiational stage (i.e. 7 days before and 7 days after DMBA application), promotional stage (i.e. from the time of croton oil application) and at both the stages (i.e. 7 days prior to DMBA application & continued till the end of experiment) to the mice, recorded a significant reduction in tumor incidence to 37.5, 50 & 25% respectively in comparison to the carcinogen treated control, where tumor incidence was found as 100%. Tumor yield and Tumor burden were also significantly reduced by SCE. Similarly, the cumulative number of papillomas after 16 weeks was 68 in the control group, which was reduced to 15, 21 & 8 in the animals treated with the SCE continuously at peri-, post- and peri- & post- initiation stage respectively. A significant impairment was noticed in the levels of reduced glutathione, superoxide dismutase, catalase & protein and enhancement in LPO in liver and skin of carcinogen treated control mice as compared with vehicle treated mice. All such parameters were returned to near normal value by administration of SCE to DMBA treated mice. These results suggest a possible chemopreventive property of S.cumini against DMBA induced skin carcinogenesis in mice. PMID:21147816

  20. The effects of PAHs and N-PAHs on retinoid signaling and Oct-4 expression in vitro.

    PubMed

    Beníšek, Martin; Kubincová, Petra; Bláha, Luděk; Hilscherová, Klára

    2011-02-01

    Polycyclic aromatic hydrocarbons (PAHs) and their N-heterocyclic analogs (N-PAHs) are important environmental contaminants with negative effects in living organisms, including teratogenicity and embryotoxicity. Though most studies linked their embryotoxicity with aryl hydrocarbon receptor (AhR) and cytochrome P450 activation, the exact mechanism is not known. Other mechanisms such as disruption of retinoid signaling were recently suggested to be of importance. This study investigated PAHs and N-PAHs interference with retinoid signaling in vitro by modulating all-trans retinoic acid (ATRA) mediated response in a reporter gene assay using P19/A15 cell line. Further, effects on pluripotency and differentiation processes were evaluated by measuring octamer-4 (Oct-4), an important pluripotency marker and master differentiation factor. Two of the studied compounds, benz[a]anthracene and benz[c]acridine significantly up-regulated ATRA-mediated response in the co-exposure with a range of ATRA concentrations. Another structural N-PAH variant, 1,7-phenanthroline, downregulated ATRA-mediated response at most of tested ATRA concentrations and exposure times. Interesting concentration-dependent biphasic effects (i.e. downregulation with subsequent up-regulation to control levels) were observed at co-exposures of ATRA and parent PAH phenanthrene. Non significant Oct-4 modulation in co-exposure with ATRA was observed at compounds, which potentiated ATRA-mediated effects in the reporter gene assay. On the other hand, 1,7-phenanthroline and phenanthrene significantly suppressed Oct-4 levels in higher tested concentrations. Our results further extend the knowledge of PAH and N-PAH in vitro effects and indicate that these environmental toxicants may have influence on differentiation process and embryonic development by interfering with ATRA signaling and by modulating levels of Oct-4. PMID:21111795

  1. The temporal variability of the profile of carcinogenic polycyclic aromatic hydrocarbons in urban air: a study in a medium traffic area in Rome, 1993-1998

    NASA Astrophysics Data System (ADS)

    Menichini, E.; Monfredini, F.; Merli, F.

    The constancy, both temporal and spatial, of the profile of polycyclic aromatic hydrocarbons (PAHs) relative to benzo[a]pyrene (BaP) is a prerequisite to using the BaP-indicator approach in the carcinogenic risk assessment for PAHs. The principal aim of this study was to provide a contribution to validate this approach, by studying the variability of the profile at a typical urban site through a multi-year data set and by comparing the profiles available for different cities. Seven carcinogenic PAHs (benz[a]anthracene, benzo[b+j+k]fluoranthenes, BaP, indeno[1,2,3-cd]pyrene, dibenz[a,h]anthracene) were determined in PM 10 24-h samples collected every third day at a road site; moreover, benzo[e]pyrene was determined as a reference PAH due to its stability. The profile was found stable from year to year. Besides, it was similar to those recently found in other European cities (observed differences within a factor of four) and to those elaborated from earlier (1970s-1980s) investigations. The substantial similarity of profiles, both temporal (on an annual basis) and spatial, supports the validity of the BaP-indicator approach. Large PAH-to-PAH differences were, however, found in the seasonal pattern of profile: they were explained by the different atmospheric degradability of PAHs, whose effect is enhanced under the meteoclimatic conditions typical of the European Mediterranean countries. PAH annual means showed a slight declining trend since 1994. In the last sampling year, mean concentration of BaP was 1.2 ng m -3. Within-year differences among monthly averaged PAH concentrations were observed, as large as up to 44-fold for BaP, underlining the need for whole-year monitoring.

  2. Degradation of polycyclic aromatic hydrocarbons (PAHs) present in used motor oil and implications for urban runoff quality

    NASA Astrophysics Data System (ADS)

    Ferreira, M.; Stenstrom, M. K.; Lau, S.

    2013-12-01

    Polycyclic aromatic hydrocarbons (PAHs) are common organic pollutants of urban stormwater runoff due to atmospheric deposition, vehicle-related discharges, and coal tar pavement sealants. The US EPA lists sixteen PAHs as priority pollutants and seven of those are potential carcinogenic compounds. Due to their molecular structure, PAHs tend to attach to particles that will subsequently be deposited as sediments in waterways. This study focuses on the degradation of PAHs present in used motor oil. Four experimental setups were used to simulate volatilization and photooxidation in the degradation of sixteen PAHs as observed for up to 54 days. The volatilization-only experiment showed substantial reduction only in the concentration of Napthalene (Nap). However, photooxidation-only was more efficient in degrading PAHs. In this process, substantial reduction in the concentrations of Nap, Acenapthene (Anthe), Anthracene (ANT), Fluoranthene (FLT), Pyrene (PYR), Benz[a]anthracene (BaA), Benzo[a]pyrene (BaP), Indeno[1,2,3,cd]pyrene (INP), and Benz[g,h,i]perylene (BghiP) were observed as early as five days. The two volatilization-photooxidation experiments exhibited substantial reduction in the concentrations of Fluorene (FLU), Chrysene (CHR) and Benzo[b]fluoranthene (BbF), in addition to the PAHs reduced by photooxidation-only. Phenanthrene (PHE), Fluoranthene (FLT), and Benzo[b]fluoranthene (BbF) only exhibited substantial decreased concentrations after 20 days in the volatilization-photooxidation experiment. One PAH, acenapthylene (Anthy), was not detected in the original sample of used motor oil. The highest degradations were observed in the combined volatilization-photooxidation experiment. In regions with infrequent rainfall, such as Southern California, molecules of PAHs attached to highway particles will have time to undergo degradation prior to transport. Therefore, PAHs may be present in lower concentrations in highway runoff in dry climates than in rainy climates

  3. Comparative developmental toxicity of environmentally relevant oxygenated PAHs

    PubMed Central

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

    2014-01-01

    Oxygenated polycyclic aromatic hydrocarbons (OPAHs) are byproducts of combustion and photo-oxidation of parent PAHs. OPAHs are widely present in the environment and pose an unknown hazard to human health. The developing zebrafish was used to evaluate a structurally diverse set of 38 OPAHs for malformation induction, gene expression changes and mitochondrial function. Zebrafish embryos were exposed from 6 to 120 h post fertilization (hpf) to a dilution series of 38 different OPAHs and evaluated for 22 developmental endpoints. AHR activation was determined via CYP1A immunohistochemistry. Phenanthrenequinone (9,10-PHEQ), 1,9-benz-10-anthrone (BEZO), xanthone (XAN), benz(a)anthracene-7,12-dione (7,12-B[a]AQ), and 9,10-anthraquinone (9,10-ANTQ) were evaluated for transcriptional responses at 48 hpf, prior to the onset of malformations. qRT-PCR was conducted for a number of oxidative stress genes, including the glutathione transferase(gst), glutathione peroxidase(gpx), and superoxide dismutase(sod) families. Bioenergetics was assayed to measure in vivo oxidative stress and mitochondrial function in 26 hpf embryos exposed to OPAHs. Hierarchical clustering of the structure-activity outcomes indicated that the most toxic of the OPAHs contained adjacent diones on 6-carbon moieties or terminal, para-diones on multi-ring structures. 5-carbon moieties with adjacent diones were among the least toxic OPAHs while the toxicity of multi-ring structures with more centralized para-diones varied considerably. 9,10-PHEQ, BEZO, 7,12-B[a]AQ, and XAN exposures increased expression of several oxidative stress related genes and decreased oxygen consumption rate (OCR), a measurement of mitochondrial respiration. Comprehensive in vivo characterization of 38 structurally diverse OPAHs indicated differential AHR dependency and a prominent role for oxidative stress in the toxicity mechanisms. PMID:23684558

  4. Rates of Microbial Transformation of Polycyclic Aromatic Hydrocarbons in Water and Sediments in the Vicinity of a Coal-Coking Wastewater Discharge †

    PubMed Central

    Herbes, Stephen E.

    1981-01-01

    To facilitate predictions of the transport and fate of contaminants at future coal conversion facilities, rates of microbial transformation of polycyclic aromatic hydrocarbons were measured in stream water and sediment samples collected in the vicinity of a coal-coking treated wastewater discharge from November 1977 through August 1979. Six radiolabeled polycyclic aromatic hydrocarbons were incubated with sediment and water samples; 14CO2, cell-bound 14C, and polar transformation products were isolated and quantified. Whereas 14CO2 and bound 14C were major transformation products in sediment assays, soluble polar 14C dominated transformation in water samples. Mean rate constants (measured at 20°C) in sediments collected downstream from the effluent outfall were 7.8 × 10−2 h−1 (naphthalene), 1.6 × 10−2 h−1 (anthracene), and 3.3 × 10−3 h−1 [benz(a)anthracene], which corresponded to turnover times of 13, 62, and 300 h, respectively. No unequivocal evidence for transformation of benzo(a)pyrene or dibenz(a,h)anthracene was obtained. Only naphthalene and anthracene transformations were observed in water samples; rate constants were consistently 5- and 20-fold lower, respectively, than in the corresponding sediment samples. The measured rate constants for anthracene transformation in July 1978 sediment samples were not related to total heterotroph numbers. In late July 1978, the effluent was diverted from the primary study area; however, no differences were observed either in transformation rate constants or in the downstream/upstream sediment rate constant ratio. These results are consistent with the hypothesis that continuous inputs of polycyclic aromatic hydrocarbons result in an increased ability within a microbial community to utilize certain polycyclic aromatic hydrocarbons. However, because transformation rates remained elevated for more than 1 year after removal of the polycyclic aromatic hydrocarbon source, microbial communities may shift only

  5. Pig-a Mutation: Kinetics in Rat Erythrocytes Following Exposure to Five Prototypical Mutagens

    PubMed Central

    Phonethepswath, Souk; Franklin, Dean; Torous, Dorothea K.; Bryce, Steven M.; Bemis, Jeffrey C.; Raja, Sarojini; Avlasevich, Svetlana; Weller, Pamela; Hyrien, Ollivier; Palis, James; MacGregor, James T.; Dertinger, Stephen D.

    2010-01-01

    An in vivo mutation assay has been developed based on flow cytometric enumeration of glycosylphosphatidylinositol (GPI) anchor–deficient rat erythrocytes. With this method, blood is incubated with anti-CD59-PE and SYTO 13 dye, and flow cytometry is used to score the frequency of CD59-negative erythrocytes. The experiments described herein were designed to define the kinetics of mutant erythrocyte appearance and disappearance from peripheral blood to support appropriate treatment and sampling designs for the assay. Wistar Han rats were treated with one of five prototypical mutagens: N-ethyl-N-nitrosourea (ENU); 7,12-dimethyl-1,2-benz[a]anthracene (DMBA); 4-nitroquinoline-1-oxide; benzo[a]pyrene; and N-methyl-N-nitrosourea. ENU and DMBA were also evaluated in Sprague Dawley rats. Animals were treated on three consecutive days (days 1–3) via oral gavage, and blood specimens were obtained on days −1, 4, 15, 30, 45, and 90 (and day 180 for ENU). A second endpoint of genotoxicity, the frequency of peripheral blood micronucleated reticulocytes, was measured on day 4. Each chemical induced micronuclei and the GPI anchor–deficient phenotype. Increased mutant cell frequencies were evident at day 15. Mutant reticulocyte frequencies remained relatively stable for some chemicals, but others peaked and then dropped significantly. The differences in kinetics observed are presumably related to the degree to which mutation occurs in hematopoietic stem cells versus more committed cells with limited self-renewal capacity. Collectively, the results suggest that enumerating GPI anchor–deficient erythrocytes is an efficient means of evaluating the in vivo mutagenic potential of chemicals. The kinetics and ease of scoring this blood-based endpoint suggest that integration into routine toxicology studies will be feasible. PMID:19965957

  6. Integration of Mutation and Chromosomal Damage Endpoints into 28-Day Repeat Dose Toxicology Studies

    PubMed Central

    Dertinger, Stephen D.; Phonethepswath, Souk; Franklin, Dean; Weller, Pamela; Torous, Dorothea K.; Bryce, Steven M.; Avlasevich, Svetlana; Bemis, Jeffrey C.; Hyrien, Ollivier; Palis, James; MacGregor, James T.

    2010-01-01

    Two endpoints of genetic toxicity, mutation at the X-linked Pig-a gene and chromosomal damage in the form of micronucleated reticulocytes (MN-RETs), were evaluated in blood samples obtained from 28-day repeat-dosing studies typical of those employed in toxicity evaluations. Male Wistar Han rats were treated at 24-h intervals on days 1 through 28 with one of five prototypical genotoxicants: N-ethyl-N-nitrosourea, 7,12-dimethyl-12-benz[a]anthracene, 4-nitroquinoline-1-oxide (4NQO), benzo(a)pyrene, and N-methyl-N-nitrosourea. Flow cytometric scoring of CD59-negative erythrocytes (indicative of glycosylphosphatidylinositol anchor deficiency and hence Pig-a mutation) was performed using blood specimens obtained on days −1, 15, 29, and 56. Blood specimens collected on days 4 and 29 were evaluated for MN-RET frequency using flow cytometry–based MicroFlow Kits. With the exception of 4NQO, each chemical induced significant increases in the frequency of MN-RETs on days 4 and 29. All five agents increased the frequency of mutant phenotype (CD59 negative) reticulocytes (RETs) and erythrocytes. Mutation responses in RETs occurred earlier than in erythrocytes and tended to peak, or nearly peak, at day 29. In contrast, the mutant phenotype erythrocyte responses were modest on day 29 and required additional time to reach their maximal value. The observed kinetics were expected based on the known turnover of RETs and erythrocytes. The data show that RETs can serve as an appropriate indicator cell population for 28-day studies. Collectively, these data suggest that blood-based genotoxicity endpoints can be effectively incorporated into routine toxicology studies, a strategy that would reduce animal usage while providing valuable genetic toxicity information within the context of other toxicological endpoints. PMID:20202993

  7. Structurally Distinct Polycyclic Aromatic Hydrocarbons Induce Differential Transcriptional Responses in Developing Zebrafish

    SciTech Connect

    Goodale, Britton; Tilton, Susan C.; Corvi, Margaret M.; Wilson, Glenn V.; Janszen, Derek B.; Anderson, Kim A.; Waters, Katrina M.; Tanguay, Robert

    2013-11-01

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the environment as components of fossil fuels and by-products of combustion. These multi-ring chemicals differentially activate the aryl hydrocarbon receptor (AHR) in a structurally dependent manner, and induce toxicity via both AHR-dependent and -independent mechanisms. PAH exposure is known to induce developmental malformations in zebrafish embryos, and recent studies have shown cardiac toxicity induced by compounds with low AHR affinity. Unraveling the potentially diverse molecular mechanisms of PAH toxicity is essential for understanding the hazard posed by complex PAH mixtures present in the environment. We analyzed transcriptional responses to PAH exposure in zebrafish embryos exposed to benz(a)anthracene (BAA), dibenzothiophene (DBT) and pyrene (PYR) at concentrations that induced developmental malformations by 120 h post-fertilization (hpf). Whole genome microarray analysis of mRNA expression at 24 and 48 hpf identified genes that were differentially regulated over time and in response to the three PAH structures. PAH body burdens were analyzed at both time points using GC-MS, and demonstrated differences in PAH uptake into the embryos. This was important for discerning dose-related differences from those that represented unique molecular mechanisms. While BAA misregulated the least number of transcripts, it caused strong induction of cyp1a and other genes known to be downstream of the AHR, which were not induced by the other two PAHs. Analysis of functional roles of misregulated genes and their predicted regulatory transcription factors also distinguished the BAA response from regulatory networks disrupted by DBT and PYR exposure. These results indicate that systems approaches can be used to classify the toxicity of PAHs based on the networks perturbed following exposure, and may provide a path for unraveling the toxicity of complex PAH mixtures.

  8. Oxidation of PAH trans-Dihydrodiols by Human Aldo-Keto Reductase AKR1B10

    PubMed Central

    Quinn, Amy M.; Harvey, Ronald G.; Penning, Trevor M.

    2009-01-01

    AKR1B10 has been identified as a potential biomarker for human non-small cell lung carcinoma and as a tobacco exposure and response gene. AKR1B10 functions as an efficient retinal reductase in vitro, and may regulate retinoic acid homeostasis. However, the possibility that this enzyme is able to activate polycyclic aromatic hydrocarbon (PAH) trans-dihydrodiols to form reactive and redox-active o-quinones has not been investigated to date. AKR1B10 was found to oxidize a wide range of PAH trans-dihydrodiol substrates in vitro to yield PAH o-quinones. Reactions of AKR1B10 proceeded with improper stereochemistry, since it was specific for the minor (+)-benzo[a]pyrene-7S,8S-dihydrodiol diastereomer formed in vivo. However, AKR1B10 displayed reasonable activity in the oxidation of both the (−)-R,R and (+)-S,S stereoisomers of benzo[g]chrysene-11,12-dihydrodiol and oxidized the potentially relevant, albeit minor, (+)-benz[a]anthracene-3S,4S-dihydrodiol metabolite. We find that AKR1B10 is therefore likely to play a contributing role in the activation of PAH trans-dihydrodiols in human lung. AKR1B10 retinal reductase activity was confirmed in vitro and found to be 5- to 150-fold greater than the oxidation of PAH trans-dihydrodiols examined. AKR1B10 was highly expressed at the mRNA and protein levels in human lung adenocarcinoma A549 cells, and robust retinal reductase activity was measured in lysates of these cells. The much greater catalytic efficiency of retinal reduction compared to PAH trans-dihydrodiol metabolism suggests AKR1B10 may play a greater role in lung carcinogenesis through dysregulation of retinoic acid homeostasis than through oxidation of PAH trans-dihydrodiols. PMID:18788756

  9. Study on prevention of two-stage skin carcinogenesis by Hibiscus rosa sinensis extract and the role of its chemical constituent, gentisic acid, in the inhibition of tumour promotion response and oxidative stress in mice.

    PubMed

    Sharma, S; Khan, N; Sultana, S

    2004-02-01

    We designed the present study to investigate the role of gentisic acid in the chemopreventive activity of Hibiscus rosa sinensis extract on 7,12-dimethyl benz(a)anthracene (DMBA)/croton oil-mediated carcinogenesis in mouse skin via 12-O-tetradecanoyl phorbol-13-acetate (TPA)-induced tumour promotion response and oxidative stress. Single topical application of DMBA followed by twice weekly applications of croton oil after one week for 20 weeks resulted in 100% incidence of tumours in animals in 15 weeks. However, application of H. rosa sinensis extract 30 minutes prior to the application of croton oil twice weekly for 20 weeks caused significant reduction in the number of tumours per mouse and the percentage of tumour-bearing mice. Also, the latency period for the appearance of the first tumour was delayed on H. rosa sinensis pretreatment. A single topical application of TPA caused significant depletion in reduced glutathione (GSH) content, activities of its metabolizing and antioxidant enzymes, while malondialdehyde (MDA) formation, H2O2 content, ornithine decarboxylase (ODC) activity and DNA synthesis were significantly increased. Interestingly, pretreatment of H. rosa sinensis extract (3.5 mg and 7 mg/kg body weight) and gentisic acid (2.0 microg and 4.0 microg/0.2 ml acetone per animal) restored the levels of GSH, and its metabolizing and antioxidant enzymes (P<0.05). There was also a statistically significant reduction in MDA formation and H2O2 content (P<0.05) at both doses. Although inhibition of ODC activity by gentisic acid was not dose-dependent, thymidine incorporation in DNA (P<0.05) was dose-dependently recovered by the plant extract and its chemical constituent. We therefore propose that gentisic acid has a role in the modulatory activity of H. rosa sinensis extract. PMID:15075789

  10. Metabolism of fluperlapine by cytochrome P450-dependent and flavin-dependent monooxygenases in continuous cultures of rat and human cells.

    PubMed

    Fischer, V; Wiebel, F J

    1990-04-15

    The metabolism of fluperlapine, a neuroleptic dibenzazepine derivative with a N-methyl-piperazinyl substituent, was investigated in continuous cultures of rat and human cells which express various cytochrome P450-dependent monooxygenase activities. The differentiated rat hepatoma cells H4IIEC3/G- and their variants 2sFou and FGC-5 metabolized fluperlapine predominantly by N-oxygenation and only to a minor degree by N-demethylation or glucuronidation of primary phenolic products. Total fluperlapine metabolism in dedifferentiated rat hepatoma cells H5 and partially differentiated human hepatoma cells HepG2 was much smaller than in the differentiated rat hepatoma lines. This was primarily attributable to their low capacity for N-oxygenation. Human lung adenocarcinoma lines NCI-H322 and NCI-H358 formed only trace amounts of fluperlapine N-oxide. Pretreatment of 2sFou cells with benz(a)anthracene, phenobarbital or dexamethasone markedly increased the formation of N-demethylated and glucuronidated products but did not affect the rate of N-oxide formation. Guanethidine and cysteamine, inhibitors of flavin-dependent monooxygenase activity, reduced fluperlapine N-oxidation more strongly than aldrin epoxidation, a marker for cytochrome P450 activity. In contrast, n-octylamine inhibited aldrin epoxidation but was without effect on fluperlapine N-oxygenation. The results suggest that certain cells in continuous culture are capable of expressing flavin-dependent monooxygenase(s) in addition to cytochrome P450-containing monooxygenases. Such cells may offer useful systems for studying the oxidative metabolism of a broad spectrum of xenobiotics and analysing the importance of the two oxygenation reactions for the biological effects of their substrates. PMID:2322314

  11. Substrate Specificity and Structural Characteristics of the Novel Rieske Nonheme Iron Aromatic Ring-Hydroxylating Oxygenases NidAB and NidA3B3 from Mycobacterium vanbaalenii PYR-1

    PubMed Central

    Kweon, Ohgew; Kim, Seong-Jae; Freeman, James P.; Song, Jaekyeong; Baek, Songjoon; Cerniglia, Carl E.

    2010-01-01

    The Rieske nonheme iron aromatic ring-hydroxylating oxygenases (RHOs) NidAB and NidA3B3 from Mycobacterium vanbaalenii PYR-1 have been implicated in the initial oxidation of high-molecular-weight (HMW) polycyclic aromatic hydrocarbons (PAHs), forming cis-dihydrodiols. To clarify how these two RHOs are functionally different with respect to the degradation of HMW PAHs, we investigated their substrate specificities to 13 representative aromatic substrates (toluene, m-xylene, phthalate, biphenyl, naphthalene, phenanthrene, anthracene, fluoranthene, pyrene, benz[a]anthracene, benzo[a]pyrene, carbazole, and dibenzothiophene) by enzyme reconstitution studies of Escherichia coli. Both Nid systems were identified to be compatible with type V electron transport chain (ETC) components, consisting of a [3Fe-4S]-type ferredoxin and a glutathione reductase (GR)-type reductase. Metabolite profiles indicated that the Nid systems oxidize a wide range of aromatic hydrocarbon compounds, producing various isomeric dihydrodiol and phenolic compounds. NidAB and NidA3B3 showed the highest conversion rates for pyrene and fluoranthene, respectively, with high product regiospecificity, whereas other aromatic substrates were converted at relatively low regiospecificity. Structural characteristics of the active sites of the Nid systems were investigated and compared to those of other RHOs. The NidAB and NidA3B3 systems showed the largest substrate-binding pockets in the active sites, which satisfies spatial requirements for accepting HMW PAHs. Spatially conserved aromatic amino acids, Phe-Phe-Phe, in the substrate-binding pockets of the Nid systems appeared to play an important role in keeping aromatic substrates within the reactive distance from the iron atom, which allows each oxygen to attack the neighboring carbons. PMID:20714442

  12. Identification of a Novel Calotropis procera Protein That Can Suppress Tumor Growth in Breast Cancer through the Suppression of NF-κB Pathway

    PubMed Central

    Samy, Ramar Perumal; Rajendran, Peramaiyan; Li, Feng; Anandi, Narayana Moorthy; Stiles, Bradley G.; Ignacimuthu, Savarimuthu; Sethi, Gautam; Chow, Vincent T. K.

    2012-01-01

    Breast cancer is the most common cancer among women. To date, improvements in hormonal and cytotoxic therapies have not yet led to a sustained remission or cure. In the present study, we investigated the in vitro and in vivo antitumor activities of a novel Calotropis procera protein (CP-P) isolated from root bark. CP-P protein inhibited the proliferation and induced apoptosis of breast cancer cells through the suppression of nuclear factor kappaB (NF-kB) activation. CP-P, when administered individually or in combination with cyclophosphamide (CYC, 0.2 mg/kg) to rats with 7, 12-dimethyl benz(a)anthracene (DMBA)-induced breast cancer decreased tumor volume significantly without affecting the body weight. To elucidate the anticancer mechanism of CP-P, antioxidant activities such as superoxide dismutase (SOD), catalase (CAT), glutathione-s-transferase (GST) and non-enzymatic antioxidant - reduced glutathione (GSH), vitamin E and C generation in the breast were analyzed by various assays. SOD, CAT, GST, GSH, vitamin E and C levels were high in combination-treated groups (CP-P+CYC) versus the CYC alone-treated groups. Also, the combination was more effective in down-regulating the expression of NF-kB-regulated gene products (cyclin D1 and Bcl-2) in breast tumor tissues. Our findings indicate that CP-P possesses significant antitumor activity comparable to a commonly used anticancer drug, cyclophosphamide, and may form the basis of a novel therapy for breast cancer. PMID:23284617

  13. Induction of micronuclei and sister chromatid exchanges by polycyclic and N-heterocyclic aromatic hydrocarbons in cultured human lymphocytes

    SciTech Connect

    Warshawsky, D.; Livingston, G.K.; LaDow, K.

    1995-12-31

    Many natural environments are contaminated with carcinogenic polycyclic aromatic hydrocarbons (PAHs) and N-heterocyclic aromatic hydrocarbons (NHAs) as complex mixtures of coal tar, petroleum, and shale oil. These potentially hazardous substances are prevalent at many former tar production and coal gasification sites. Three polycyclic [benzo(a)pyrene (BaP), benz(a)anthracene (BAA), and 7, 12-dimethylbenz(a)anthracene (DMBA)] and two N-heterocyclic [7H-dibenzo(c,g)carbazole (DBC), and dibenz(a,j)acridine (DBA)] aromatic hydrocarbons were analyzed for cytotoxic and genotoxic effects on human lymphocytes. All of these polyaromatic compounds are normally present in the environment, except for DMBA. Lymphocytes from healthy donors were isolated from whole blood. The 5-ring polycyclic aromatic BaP consistently induced micronuclei in a linear dose-dependent manner with doses from 0.1-10.0 {mu}g/ml, whereas the 4-ring compounds (BAA and DMBA) had no effect on the induction of micronuclei above controls except at 5 and 10 {mu}g/ml. Of the two N-heterocyclic compounds DBC produced a significant increase in micronuclei in lymphocytes, but the dose response tended to plateau above 0.1 {mu}g/ml. DBA showed an effect on the frequency of micronuclei above controls only at high doses of 5 and 10 {mu}g/ml. The average background frequency of micronuclei for 7 lymphocyte donors averaged 3.1 per 1,000 stimulated cells, whereas the average frequency of micronuclei at 10 {mu}g/ml BaP was 36.8 per 1,000 stimulated cells. The lowest effective dose in 2 donors for BaP occurred at 0.1 {mu}g/ml. 61 refs., 2 figs., 6 tabs.

  14. Detection of aryl hydrocarbon hydroxylase activity in normal and neoplastic human breast epithelium

    SciTech Connect

    Greiner, J.W.; Malan-Shibley, L.B.; Janss, D.H.

    1980-01-28

    Studies were conducted to determine whether normal and/or neoplastic (MCF-7) human breast epithelial cells contain the microsomal aryl hydrocarbon hydroxylase (AHH) which catalyses the conversion of polycyclic aromatic hydrocarbons (PAH) to carcinogenic intermediates. Low constitutive levels of AHH activity were found in homogenates of both normal human breast epithelial and MCF-7 cells. The addition of 7,12-dimethylbenz(a)anthracene (DMBA) to the culture medium of either cell type significantly increased AHH activity. Peak induction of hydroxylase activity occurred following the in vitro addition of 10 ..mu..M DMBA. A time course of DMBA-induced AHH activity in both normal human breast epithelium and MCF-7 cells revealed maximal induction 16 hr after 10 ..mu..M DMBA was added to the culture medium. Benzo(a)pyrene (BP), 3-methylcholanthrene (MCA) and benz(a)anthracene (BA) also induced AHH activity in normal and MCF-7 cells. For example, the addition of 10 ..mu..M BP to the culture medium of either normal human breast epithelial or MCF-7 cells for 16 hr increased AHH activity 13.8 and 65.3-fold, respectively. For all PAH, the magnitude of AHH induction was substantially greater in MCF-7 than normal breast epithelial cells. Finally, ..cap alpha..-naphthoflavone inhibited BA-induced AHH activity in MCF-7 cells. The study demonstrates the presence of a PAH-inducible AHH enzyme(s) in normal human breast epithelial cells grown in primary culture and in the human breast tumor cell line, MCF-7.

  15. Experimental and Temporal Observations on the Occurrence and Abundance of Pyrogenic PAH Relative to Atmospheric Oxygen Levels

    NASA Astrophysics Data System (ADS)

    Schuneman, P. J.; Uhle, M. E.

    2004-12-01

    The Phanerozoic record of atmospheric O2 is based on a global mass balance of several dynamic geochemical cycles, with error margins reflecting such complexity. The potential for accurately determining the record of atmospheric O2 may significantly improve with the proposed method, which relies on a direct relationship between atmospheric oxygen, fuels, and fire products. The interaction between combustion and atmospheric-oxygen level during biomass burning events is investigated by comparing the occurrence and abundance of pyrogenic polycyclic aromatic hydrocarbons (PAH) from experimentally-produced, modern, Triassic, and Carboniferous chars. The combustion process consumes O2 directly from the atmosphere and thermally alters organic matter to produce chars. PAH that develop through combustion, and are preserved within chars, are expected to be more abundant at times of elevated atmospheric O2, which facilitates biomass burning efficiency. To investigate the hypothesized relationship in the geologic record, PAH have been extracted from chars of three periods - modern, Triassic, and Carboniferous - relating to 21%, 15%, and 35% atmospheric O2, respectively (Berner and Canfield, 1989). Surface samples of modern chars that developed in controlled burns set by National Park Service personnel in a mixed conifer-deciduous forest were collected at Zion National Park, Utah. Triassic fusain from Petrified Forest National Park, AZ, and Carboniferous fusain from Joggins Fossil Cliffs, Nova Scotia, were collected from floodplain- and coastal plain-deposited mudstone and sandstone. Target PAH shown to be uniquely pyrogenic include: phenanthrene, anthracene, fluoranthene, pyrene, benz(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, indeno(1,2,3-cd)pyrene, and benzo(ghi)perylene. The abundance of PAH from modern chars at Zion National Park, Triassic fusain from Petrified Forest National Park, and Carboniferous fusain from Joggins Fossil Cliffs

  16. Rapid and sensitive method for the determination of four EU marker polycyclic aromatic hydrocarbons in cereal-based foods using isotope-dilution GC/MS.

    PubMed

    Kacmaz, Sibel; Zelinkova, Zuzana; Wenzl, Thomas

    2016-04-01

    A rapid and sensitive method has been developed for the determination of the four European Union marker polycyclic aromatic hydrocarbons (PAHs; benz[a]anthracene, chrysene, benzo[b]fluoranthene and benzo[a]pyrene) in some cereal-based foods. The method is based on pressurised liquid extraction (PLE), solid-phase extraction clean-up (SPE) and isotope-dilution gas chromatography with mass-spectrometric detection (GC/MS). The developed method was calibrated for the content range of 0.05-12.5 µg kg(-1) (expressed on a product basis). Recoveries of PAH were monitored in each sample via the recovery of (13)C-labelled PAHs. Recovery values were in the range between 86% and 91%, with relative standard deviations (RSDs) between 5% and 9%. The achieved limits of detection for all analytes were below 0.05 µg kg(-1). The applicability of the method for the analysis of routine samples was studied by the analysis of a set of commercial bread and breakfast cereal samples. In all analysed samples, benzo[a]pyrene (BAP) was the most prevalent PAH with the content between 0.09 and 0.30 µg kg(-1). On average, samples showed low levels of the sum of the four EU marker PAHs (ΣPAH4) that ranged between 0.11 and 0.22 µg kg(-1) for bread samples and between 0.23 and 0.87 µg kg(-1) for breakfast cereal samples. The developed method was found suitable for the determination of PAHs in cereal-based foods like cornflakes and breads with total relative fat contents below 3.5%. PMID:26950570

  17. Distribution, compositional pattern and sources of polycyclic aromatic hydrocarbons in urban soils of an industrial city, Lanzhou, China.

    PubMed

    Jiang, Yufeng; Yves, Uwamungu J; Sun, Hang; Hu, Xuefei; Zhan, Huiying; Wu, Yingqin

    2016-04-01

    The level, distribution, compositional pattern and possible sources of polycyclic aromatic hydrocarbons (PAHs) in Lanzhou urban soil of Northwest China were investigated in this study. The total level of 22 PAHs ranged from 115 to 12,100µgkg(-1) and that of 16 priority PAHs from 82.4 to 10,900µgkg(-1). Seven carcinogenic PAHs generally accounted for 6.18-57.4% of total 22 PAHs. Compared with data from those reported about urban areas, PAH contamination in Lanzhou urban soils was moderate. Among different functional areas, higher level of PAHs was found along roadsides and in the industrial district (p<0.01), while lower levels were detected in the commercial, park and residential districts. The composition of PAHs was characterized by high molecular weight PAHs (≥4 rings), among which fluoranthene, benz[a]anthracene and phenanthrene were the most dominant components. Correlation analysis suggested that low molecular weight PAHs and high molecular weight PAHs originated from different sources and further corroborated that TOC was an important factor in the accumulation of PAHs in soil. Isomer ratios and principal component analysis indicated that PAHs in urban soil derived primarily from emissions resulting from the combustion of biomass, coal and petroleum products. Toxic equivalent concentrations (BaPeq) of soil PAHs ranged from 6.12 to 1302µgBaPeqkg(-1), with a mean of 138µgBaPeqkg(-1). The results suggested that human exposure to those soils which polluted by high concentrations of PAHs through direct ingestion or inhalation of suspended soil particles probably poses a significant risk to human health from the carcinogenic effects of PAHs. PMID:26748595

  18. Sizes and polycyclic aromatic hydrocarbon composition distributions of nano, ultrafine, fine, and coarse particulates emitted from a four-stroke motorcycle.

    PubMed

    Chien, Shu M; Huang, Yuh J

    2010-11-01

    Thus, this study was undertaken to determine the size distribution, concentration, species, and carcinogenic potency of particulate matter and particle-bound polycyclic aromatic hydrocarbons (PAHs) emitted from 4-st/mc at various speeds (idle, 15 km/h, 30 km/h). Approximately 80% of the particles emitted from the that is, they are primary inhalable particulates. The particle total number concentrations (TNCs) emitted while idling and at 15 and 30 km/h were 2.07 x 10⁴, 2.35 x 10⁴, and 2.60 x 10⁴ #/cm³, respectively; i.e., they increased at elevated speeds. Notably, most of the particles emitted at 30 km/h had diameters of less than 0.65 μm and contained higher percentages of total PAHs. Excluding incomplete combustion, we suspected that some of the lower-molecular-weight PAHs [phenanthrene (PA), anthracene (Ant), pyrene (Pyr)] obtained in the fine particles at idle originated from unburned 95-octane unleaded fuel. When operated at 15 km/h, pyrolysis of the PAHs dominated, resulting in increased amounts of medium-molecular-weight PAHs {fluorene (FL), Pyr, benz[a]anthracene (BaA), chrysene (CHR)} in the ultrafine particles. Furthermore, at 30 km/h, more pyrosynthesis products {benzo[a]pyrene (BaP), indeno[1,2,3,-cd]pyrene (IND), dibenz[a,h]anthracene (DBA)}, induced through combustion at the correspondingly higher temperature, were exhausted with the nanoparticles. Although the total concentrations of BaP-equivalent emissions were inconsistent with the total PAHs, the nanoscale-sized particulates emitted from the 4-st/mc at higher speeds had the strongest PAH-related carcinogenic potencies, which should be a great concern. PMID:20924922

  19. Estimating individual-level exposure to airborne polycyclic aromatic hydrocarbons throughout the gestational period based on personal, indoor, and outdoor monitoring

    SciTech Connect

    Choi, H.; Perera, F.; Pac, A.; Wang, L.; Flak, E.; Mroz, E.; Jacek, R.; Chai-Onn, T.; Jedrychowski, W.; Masters, E.; Camann, D.; Spengler, J.

    2008-11-15

    Current understanding on health effects of long-term polycyclic aromatic hydrocarbon (PAH) exposure is limited by lack of data on time-varying nature of the pollutants at an individual level. In a cohort of pregnant women in Krakow, Poland, we examined the contribution of temporal, spatial, and behavioral factors to prenatal exposure to airborne PAHs within each trimester and developed a predictive model of PAH exposure over the entire gestational period. The observed personal, indoor, and outdoor B(a)P levels we observed in Krakow far exceed the recommended Swedish guideline value for B(a)P of 0.1 ng/m{sup 3}. Based on simultaneously monitored levels, the outdoor PAH level alone accounts for 93% of total variability in personal exposure during the heating season. Living near the Krakow bus depot, a crossroad, and the city, center and time spent outdoors or commuting were not associated with higher personal exposure. During the nonheating season only, a 1-hr increase in environmental tobacco smoke (ETS) exposure was associated with a 10-16% increase in personal exposure to the nine measured PAHs. A 1{degree}C decrease in ambient temperature was associated with a 3-5% increase in exposure to benz(a)anthracene, benzo(k)fluoranthene, and dibenz(a,h)anthracene, after accounting for the outdoor concentration. A random effects model demonstrated that mean personal exposure at a given gestational period depends on the season, residence location, and ETS. Considering that most women reported spending < 3 hr/day outdoors, most women in the study were exposed to outdoor-originating PAHs within the indoor setting. Cross-sectional, longitudinal monitoring supplemented with questionnaire data allowed development of a gestation-length model of individual-level exposure with high precision and validity.

  20. Comparison in the in vitro inhibitory effects of major phytocannabinoids and polycyclic aromatic hydrocarbons contained in marijuana smoke on cytochrome P450 2C9 activity.

    PubMed

    Yamaori, Satoshi; Koeda, Kyoko; Kushihara, Mika; Hada, Yui; Yamamoto, Ikuo; Watanabe, Kazuhito

    2012-01-01

    Inhibitory effects of Δ⁹-tetrahydrocannabinol (Δ⁹-THC), cannabidiol (CBD), and cannabinol (CBN), the three major constituents in marijuana, and polycyclic aromatic hydrocarbons (PAHs) contained in marijuana smoke on catalytic activity of human cytochrome P450 (CYP) 2C9 were investigated. These phytocannabinoids concentration-dependently inhibited S-warfarin 7-hydroxylase and diclofenac 4'-hydroxylase activities of human liver microsomes (HLMs) and recombinant CYP2C9 (rCYP2C9). In contrast, none of the twelve PAHs including benz[a]anthracene and benzo[a]pyrene exerted substantial inhibition (IC₅₀ > 10 µM). The inhibitory potentials of Δ⁹-THC (Ki = 0.937-1.50 µM) and CBN (Ki = 0.882-1.29 µM) were almost equivalent regardless of the enzyme sources used, whereas the inhibitory potency of CBD (Ki > = 0.954-9.88 µM) varied depending on the enzyme sources and substrates used. Δ⁹-THC inhibited both S-warfarin 7-hydroxylase and diclofenac 4'-hydroxylase activities of HLMs and rCYP2C9 in a mixed manner. CBD and CBN competitively inhibited the activities of HLMs and rCYP2C9, with the only notable difference being that CBD and CBN exhibited mixed-type inhibitions against diclofenac 4'-hydroxylation and S-warfarin 7-hydroxylation, respectively, by rCYP2C9. None of Δ⁹-THC, CBD, and CBN exerted metabolism-dependent inhibition. These results indicated that the three major phytocannabinoids but not PAHs contained in marijuana smoke potently inhibited CYP2C9 activity and that these cannabinoids can be characterized as direct inhibitors for CYP2C9. PMID:22166891

  1. PAH determination based on a rapid and novel gas purge-microsyringe extraction (GP-MSE) technique in road dust of Shanghai, China: Characterization, source apportionment, and health risk assessment.

    PubMed

    Zheng, Xin; Yang, Yi; Liu, Min; Yu, Yingpeng; Zhou, John L; Li, Donghao

    2016-07-01

    A novel cleanup technique termed as gas purge-microsyringe extraction (GP-MSE) was evaluated and applied for polycyclic aromatic hydrocarbon (PAH) determination in road dust samples. A total of 68 road dust samples covering almost the entire Shanghai area were analyzed for 16 priority PAHs using gas chromatography-mass spectrometry. The results indicate that the total PAH concentrations over the investigated sites ranged from 1.04μg/g to 134.02μg/g dw with an average of 13.84μg/g. High-molecular-weight compounds (4-6 rings PAHs) were significantly dominant in the total mass of PAHs, and accounted for 77.85% to 93.62%. Diagnostic ratio analysis showed that the road dust PAHs were mainly from the mixture of petroleum and biomass/coal combustions. Principal component analysis in conjunction with multiple linear regression indicated that the two major origins of road dust PAHs were vehicular emissions and biomass/fossil fuel combustions, which contributed 66.7% and 18.8% to the total road dust PAH burden, respectively. The concentration of benzo[a]pyrene equivalent (BaPeq) varied from 0.16μg/g to 24.47μg/g. The six highly carcinogenic PAH species (benz(a)anthracene, benzo(a)pyrene, benzo(b)fluoranthene, benzo(k)fluoranthene, dibenz(a,h)anthracene, and indeno(1,2,3-cd)pyrene) accounted for 98.57% of the total BaPeq concentration. Thus, the toxicity of PAHs in road dust was highly associated with high-molecular-weight compounds. PMID:27037890

  2. Effect of Chemical Mutagens and Carcinogens on Gene Expression Profiles in Human TK6 Cells

    PubMed Central

    Godderis, Lode; Thomas, Reuben; Hubbard, Alan E.; Tabish, Ali M.; Hoet, Peter; Zhang, Luoping; Smith, Martyn T.; Veulemans, Hendrik; McHale, Cliona M.

    2012-01-01

    Characterization of toxicogenomic signatures of carcinogen exposure holds significant promise for mechanistic and predictive toxicology. In vitro transcriptomic studies allow the comparison of the response to chemicals with diverse mode of actions under controlled experimental conditions. We conducted an in vitro study in TK6 cells to characterize gene expression signatures of exposure to 15 genotoxic carcinogens frequently used in European industries. We also examined the dose-responsive changes in gene expression, and perturbation of biochemical pathways in response to these carcinogens. TK6 cells were exposed at 3 dose levels for 24 h with and without S9 human metabolic mix. Since S9 had an impact on gene expression (885 genes), we analyzed the gene expression data from cells cultures incubated with S9 and without S9 independently. The ribosome pathway was affected by all chemical-dose combinations. However in general, no similar gene expression was observed among carcinogens. Further, pathways, i.e. cell cycle, DNA repair mechanisms, RNA degradation, that were common within sets of chemical-dose combination were suggested by clustergram. Linear trends in dose–response of gene expression were observed for Trichloroethylene, Benz[a]anthracene, Epichlorohydrin, Benzene, and Hydroquinone. The significantly altered genes were involved in the regulation of (anti-) apoptosis, maintenance of cell survival, tumor necrosis factor-related pathways and immune response, in agreement with several other studies. Similarly in S9+ cultures, Benz[a]pyrene, Styrene and Trichloroethylene each modified over 1000 genes at high concentrations. Our findings expand our understanding of the transcriptomic response to genotoxic carcinogens, revealing the alteration of diverse sets of genes and pathways involved in cellular homeostasis and cell cycle control. PMID:22723965

  3. Phthalate and PAH concentrations in dust collected from Danish homes and daycare centers

    NASA Astrophysics Data System (ADS)

    Langer, Sarka; Weschler, Charles J.; Fischer, Andreas; Bekö, Gabriel; Toftum, Jørn; Clausen, Geo

    2010-06-01

    As part of the Danish Indoor Environment and Children's Health (IECH) study, dust samples were collected from 500 bedrooms and 151 daycare centers of children (ages 3 to 5) living on the island of Fyn. The present paper reports results from the analyses of these samples for five phthalate esters (diethyl phthalate (DEP), di(n-butyl) phthalate (DnBP), di(isobutyl) phthalate (DiBP), butyl benzyl phthalate (BBzP), di(2-ethylhexyl) phthalate (DEHP)) and three PAHs (pyrene, benz[a]anthracene (B[a]A) and benzo[a]pyrene (B[a]P)). The three PAHs and DEHP were detected in dust samples from all sites, while DEP, DnBP, DiBP and BBzP were detected in more than 75% of the bedrooms and more than 90% of the daycare centers. The dust mass-fractions of both phthalates and PAHs were log-normally distributed. With the exception of DEP, the mass-fractions of phthalates in dust were higher in daycare centers than homes; PAH mass-fractions in dust were similar in the two locations. There was no correlation among the different phthalates in either homes or daycare centers. In contrast, the PAH were correlated with one another - more strongly so in homes ( R2 = 0.80-0.90) than in daycare centers ( R2 = 0.28-0.45). The dust levels of several phthalates (BBzP, DnBP and DEHP) were substantially lower than those measured in a comparable study conducted 6-7 years earlier in Sweden. Although usage patterns in Denmark differ from those in Sweden, the current results may also reflect a change in the plasticizers that are used in common products including toys. PAH levels were roughly an order of magnitude lower than those measured in Berlin and Cape Cod residences, suggesting that the Danish sites are less impacted by motor vehicle emissions.

  4. Characterization of parent and oxygenated-polycyclic aromatic hydrocarbons (PAHs) in Xi'an, China during heating period: An investigation of spatial distribution and transformation.

    PubMed

    Wang, Jingzhi; Hang Ho, Steven Sai; Huang, Rujin; Gao, Meiling; Liu, Suixin; Zhao, Shuyu; Cao, Junji; Wang, Gehui; Shen, Zhenxing; Han, Yongming

    2016-09-01

    Polycyclic aromatic hydrocarbons (PAHs) and its oxygenated derivatives (OPAHs) are toxins in PM2.5. Little information has been known for their transformation in the ambient airs. In this study, PM2.5 samples were collected at 19 sampling sites in Xi'an, China during the heating period, which is classified into: urban residential, university, commercial area, suburban region, and industry. Organic compounds including PAHs, OPAHs, hopanes and cholestanes were quantified. The average of total quantified PAHs and OPAHs concentrations were 196.5 ng/m(3) and 29.4 ng/m(3), respectively, which were consistent with other northern cities in China. Statistical analyses showed that there were significant differences on the distributions of PAHs between urban and suburban regions. The industry also had distinguishable profiles compared with urban residential and commercial area for OPAHs. The greater diversity of OPAHs than PAHs might be due to different primary emission sources and transformation and degradation pathways. The ratios of OPAHs to the corresponding parent PAHs, including 9-fluorenone/fluorene, anthraquinone/anthracene, benz[a]anthracene-7,12-dione/benzo[a]anthracene were 6.2, 12.7, and 1.4, respectively, which were much higher than those for the fresh emissions from coal combustion and biomass burning. These prove the importance of secondary formation and transformation of OPAHs in the ambient airs. Biomarkers such as retene, cyclopenta[CD]pyrene and αα-homohopane were characterized for the source apportionment. With Positive Matrix Factorization (PMF) model analysis, biomass burning was recognized as the most dominant pollution sources for PAHs during the heading period, which accounted for a contribution of 37.1%. Vehicle emission (22.8%) and coal combustion (22.6%) were also contributors in Xi'an. PMID:27323290

  5. Isomeric differentiation of polycyclic aromatic hydrocarbons using silver nitrate reactive desorption electrospray ionization mass spectrometry

    PubMed Central

    Eftekhari, Mohammad; Ismail, Ali I.; Zare, Richard N.

    2014-01-01

    RATIONALE Polycyclic aromatic hydrocarbons (PAHs) are nonpolar and difficult to detect by desorption electrospray ionization. We present a new detection method based on cationization with silver ions, which has the added advantage of being able to differentiate PAHs with the same mass but different structure. METHODS 9,10-Diphenylanthracene and triptycene, in addition to four different groups of PAH isomers: (1) anthracene and phenanthrene, (2) pyrene and fluoranthene, (3) benz[a]anthracene, benz[b]anthracene (tetracene), and chrysene (4) benzo[a]pyrene and benzo[k]fluoranthene, were deposited on a paper surface and bombarded with methanol droplets containing silver nitrate. The resulting microdroplets entered a quadruple mass spectrometer for mass analysis. RESULTS The mass spectrum shows [PAH]+, [Ag + OH + PAH]+, and [Ag(PAH)n]+ n (n = 1, 2) (and [PAH + O2]+ in the case of benz[b]anthracene) ions. PAHs having a bay structure, such as phenanthrene, showed a different tendency to interact with silver ions from those PAHs having a linear arrangement of the fused benzene rings, such as anthracene. The ratios of the [PAH]+ peak intensity to that of [Ag–PAH]+, [Ag + OH + PAH]+, [Ag(PAH)2]+, and [PAH + O2]+ were used to differentiate the PAH isomers sharing the same molecular formula with different structures. For isomeric mixtures the [PAH]+ to [Ag + OH + PAH]+ ratio was found to be the most useful parameter. The uncertainty in the mole fraction of an isomeric mixture was ±0.09, 0.13, ±0.25, and ±0.1 for phenanthrene-anthracene, fl benz[a] anthracene-chrysene, and benzo[a]pyrene-benzo[k]fluoranthene, respectively. CONCLUSIONS A simple method has been developed for the detection of PAHs in desorption electrospray ionization mass spectrometry based on Ag(I) cationization. The method showed a capability to differentiate PAHs isomers (having the same molecular mass) in isomeric mixture with an uncertainty in the mole fraction of about 0.1. At high inlet temperature

  6. The effect of zinc and phytoestrogen supplementation on the changes in mineral content of the femur of rats with chemically induced mammary carcinogenesis.

    PubMed

    Skrajnowska, Dorota; Korczak, Barbara Bobrowska-; Tokarz, Andrzej; Kazimierczuk, Agata; Klepacz, Marta; Makowska, Justyna; Gadzinski, Blazej

    2015-10-01

    The aim of this study was to assess skeletal effects of zinc or zinc with phytoestrogen (resveratrol or genistein) supplementation in an animal model of rats with DMBA-induced mammary carcinogenesis. The changes in bone parameters such as the length and mass were examined, as well as the changes in concentrations of selected minerals: calcium, magnesium, zinc, iron and phosphorus. Moreover, the investigations focused on finding the differences between the levels of iron and zinc in other tissues: the liver, spleen and serum of the examined rats. Fifty-six female Sprague-Dawley rats, 40 days old, were divided into four groups, regardless of the diets: standard (77mg Zn kg/food), zinc (4.6mg/mL via gavage), zinc (4.6mg/mL) plus resveratrol (0.2mg/kgbw), and zinc (4.6mg/mL) plus genistein (0.2mg/kgbw) for a period from 40 days until 20 weeks of age. The study rats were also treated with 7,12-dimethyl-1,2-benz[a]anthracene (DMBA) to induce mammary carcinogenesis. The applied diet and the advanced mammary cancer did not affect macrometric parameters of the rats' bones, but they strongly affected their mineral content. It was found that mammary cancer, irrespectively of the applied diet, significantly modified the iron level in the femur, liver, spleen and serum of the examined rats. In addition, zinc supplementation significantly lowered the levels of calcium, magnesium and phosphorus in the femur of rats with mammary cancer as compared with respective levels in the control group. So, it was found that additional supplementation with zinc, which is generally considered to be an antioxidant, with the co-existing mammary carcinoma, increased the unfavorable changes as concerns the stability of bone tissue. The appropriate combination of zinc and phytoestrogens (resveratrol or genistein) could help prevent or slow bone loss associated with a range of skeletal disorders in breast cancer. PMID:26302916

  7. PAH distributions in sediments in the oil sands monitoring area and western Lake Athabasca: Concentration, composition and diagnostic ratios.

    PubMed

    Evans, Marlene; Davies, Martin; Janzen, Kim; Muir, Derek; Hazewinkel, Rod; Kirk, Jane; de Boer, Dirk

    2016-06-01

    Oil sands activities north of Fort McMurray, Alberta, have intensified in recent years with a concomitant debate as to their environmental impacts. The Regional Aquatics Monitoring Program and its successor, the Joint Canada-Alberta Implementation Plan for Oil Sands Monitoring (JOSM), are the primary aquatic programs monitoring this industry. Here we examine sediment data (collected by Ekman grabs) to investigate trends and sources of polycyclic aromatic hydrocarbons (PAHs), supplementing these data with sediment core studies. Total PAH (ΣPAH) concentrations were highest at Shipyard Lake (6038 ± 2679 ng/g) in the development center and lower at Isadore's Lake (1660 ± 777 ng/g) to the north; both lakes are in the Athabasca River Valley and lie below the developments. ΣPAH concentrations were lower (622-930 ng/g) in upland lakes (Kearl, McClelland) located further away from the developments. ΣPAH concentrations increased at Shipyard Lake (2001-2014) and the Ells River mouth (1998-2014) but decreased in nearshore areas at Kearl Lake (2001-2014) and a Muskeg River (2000-2014) site. Over the longer term, ΣPAH concentrations increased in Kearl (1934-2012) and Sharkbite (1928-2010) Lakes. Further (200 km) downstream in the Athabasca River delta, ΣPAH concentrations (1029 ± 671 ng/g) increased (1999-2014) when %sands were included in the regression model; however, 50 km to the east, concentrations declined (1926-2009) in Lake Athabasca. Ten diagnostic ratios based on anthracene, phenanthrene, fluoranthene, pyrene, benz[a]anthracene, chrysene, indeno[123-cd]pyrene, dibenz[a,h]anthracene, dibenzothiophene and retene were examined to infer spatial and temporal trends in PAH sources (e.g., combustion versus petrogenic) and weathering. There was some evidence of increasing contributions of unprocessed oil sands and bitumen dust to Shipyard, Sharkbite, and Isadore's Lakes and increased combustion sources in the Athabasca River delta. Some CCME interim

  8. Light-Induced Cytotoxicity of 16 Polycyclic Aromatic Hydrocarbons on the US EPA Priority Pollutant List in Human Skin HaCaT Keratinocytes: Relationship Between Phototoxicity and Excited State Properties

    PubMed Central

    Wang, Shuguang; Sheng, Yinghong; Feng, Manliang; Leszczynski, Jerzy; Wang, Lei; Tachikawa, Hiroyasu; Yu, Hongtao

    2013-01-01

    The photocytotoxicity of 16 polycyclic aromatic hydrocarbons (PAHs) on the priority pollutant list of the United States Environmental Protection Agency (US EPA) were tested in human skin HaCaT keratinocytes. A selected PAH was mixed with HaCaT cells and irradiated with a solar simulator lamp for a dose equivalent to 5 min of outdoor sunlight and the cell viability was determined immediately and also after 24 h of incubation. For the cells without incubation after the treatments, it is found that all PAHs with three rings or less, except anthracene, are not photocytotoxic, while the four or five-ring PAHs (except chrysene), benz[a]anthracene, dibenzo[a,h]anthracene, benzo[ghi]perylene, benzo[a]pyrene, indeno[1,2,3-cd]pyrene, benzo[b]fluorenthene, fluorenthene, and pyrene, are photocytotoxic to the human skin HaCaT keratinocytes. If the cells were incubated for 24 h after the treatments, the photocytotoxic effect of the PAHs was greatly amplified in comparison to the nonincubated cells. For the 24 h incubated cells, all PAHs except naphthalene exhibit photocytotoxicity to some extent. Exposure to 5 μM of the 4- and 5-ring PAHs (except chrysene) and 3-ring anthracene more than 80% of the cells lose viability. The photocytotoxicity of the PAHs correlates well with several of their excited state properties: light absorption, excited singlet-state energy, excited triplet-state energy, and HOMO-LUMO energy gap. All the photocytotoxic PAHs absorb light at >300 nm, in the solar UVB and UVA region. There is a threshold for each of the three excited state descriptors of a photocytotoxic PAH: singlet energy <355 kJ/mol (corresponding to 337 nm light), triplet energy <230 kJ/mol (corresponding to 520 nm light), HOMO-LUMO gap <3.6 eV (corresponding to 344 nm light) obtained at the Density Functional Theory B3LYP/6-31G(d) level. PMID:17497637

  9. 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.

  10. Biological impact of environmental polycyclic aromatic hydrocarbons (ePAHs) as endocrine disruptors.

    PubMed

    Zhang, Yanyan; Dong, Sijun; Wang, Hongou; Tao, Shu; Kiyama, Ryoiti

    2016-06-01

    Polycyclic aromatic hydrocarbons (PAHs) are often detected in the environment and are regarded as endocrine disruptors. We here designated mixtures of PAHs in the environment as environmental PAHs (ePAHs) to discuss their effects collectively, which could be different from the sum of the constituent PAHs. We first summarized the biological impact of environmental PAHs (ePAHs) found in the atmosphere, sediments, soils, and water as a result of human activities, accidents, or natural phenomena. ePAHs are characterized by their sources and forms, followed by their biological effects and social impact, and bioassays that are used to investigate their biological effects. The findings of the bioassays have demonstrated that ePAHs have the ability to affect the endocrine systems of humans and animals. The pathways that mediate cell signaling for the endocrine disruptions induced by ePAHs and PAHs have also been summarized in order to obtain a clearer understanding of the mechanisms responsible for these effects without animal tests; they include specific signaling pathways (MAPK and other signaling pathways), regulatory mechanisms (chromatin/epigenetic regulation, cell cycle/DNA damage control, and cytoskeletal/adhesion regulation), and cell functions (apoptosis, autophagy, immune responses/inflammation, neurological responses, and development/differentiation) induced by specific PAHs, such as benz[a]anthracene, benzo[a]pyrene, benz[l]aceanthrylene, cyclopenta[c,d]pyrene, 7,12-dimethylbenz[a]anthracene, fluoranthene, fluorene, 3-methylcholanthrene, perylene, phenanthrene, and pyrene as well as their derivatives. Estrogen signaling is one of the most studied pathways associated with the endocrine-disrupting activities of PAHs, and involves estrogen receptors and aryl hydrocarbon receptors. However, some of the actions of PAHs are contradictory, complex, and unexplainable. Although several possibilities have been suggested, such as direct interactions between PAHs and

  11. Deviation from additivity in mixture toxicity: relevance of nonlinear dose-response relationships and cell line differences in genotoxicity assays with combinations of chemical mutagens and gamma-radiation.

    PubMed Central

    Lutz, Werner K; Vamvakas, Spyros; Kopp-Schneider, Annette; Schlatter, Josef; Stopper, Helga

    2002-01-01

    Sublinear dose-response relationships are often seen in toxicity testing, particularly with bioassays for carcinogenicity. This is the result of a superimposition of various effects that modulate and contribute to the process of cancer formation. Examples are saturation of detoxification pathways or DNA repair with increasing dose, or regenerative hyperplasia and indirect DNA damage as a consequence of high-dose cytotoxicity and cell death. The response to a combination treatment can appear to be supra-additive, although it is in fact dose-additive along a sublinear dose-response curve for the single agents. Because environmental exposure of humans is usually in a low-dose range and deviation from linearity is less likely at the low-dose end, combination effects should be tested at the lowest observable effect levels (LOEL) of the components. This principle has been applied to combinations of genotoxic agents in various cellular models. For statistical analysis, all experiments were analyzed for deviation from additivity with an n-factor analysis of variance with an interaction term, n being the number of components tested in combination. Benzo[a]pyrene, benz[a]anthracene, and dibenz[a,c]anthracene were tested at the LOEL, separately and in combination, for the induction of revertants in the Ames test, using Salmonella typhimurium TA100 and rat liver S9 fraction. Combined treatment produced no deviation from additivity. The induction of micronuclei in vitro was investigated with ionizing radiation from a 137Cs source and ethyl methanesulfonate. Mouse lymphoma L5178Y cells revealed a significant 40% supra-additive combination effect in an experiment based on three independent replicates for controls and single and combination treatments. On the other hand, two human lymphoblastoid cell lines (TK6 and WTK1) as well as a pilot study with human primary fibroblasts from fetal lung did not show deviation from additivity. Data derived from one cell line should therefore

  12. Comparative developmental toxicity of environmentally relevant oxygenated PAHs

    SciTech Connect

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

    2013-09-01

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

  13. Inhibition of the mutagenicity of bay-region diol epoxides of polycyclic aromatic hydrocarbons by naturally occurring plant phenols: Exceptional activity of ellagic acid

    PubMed Central

    Wood, Alexander W.; Huang, Mou-Tuan; Chang, Richard L.; Newmark, Harold L.; Lehr, Roland E.; Yagi, Haruhiko; Sayer, Jane M.; Jerina, Donald M.; Conney, Allan H.

    1982-01-01

    concentrations of ellagic acid are needed to inhibit the mutagenic activity of the chemically less reactive bay-region diol epoxides of benz[a]anthracene, chrysene, and benzo[c]phenanthrene. These studies demonstrate that ellagic acid is a potent antagonist of the adverse biological effects of the ultimate carcinogenic metabolites of several polycyclic aromatic hydrocarbons and suggest that this naturally occurring plant phenol, normally ingested by humans, may inhibit the carcinogenicity of polycyclic aromatic hydrocarbons. PMID:6752950

  14. Amelioration of soil PAH and heavy metals by combined application of fly ash and biochar

    NASA Astrophysics Data System (ADS)

    Masto, Reginald; George, Joshy; Ansari, Md; Ram, Lal

    2016-04-01

    Generation of electricity through coal combustion produces huge quantities of fly ash. Sustainable disposal and utilization of these fly ash is a major challenge. Fly ash along with other amendments like biochar could be used for amelioration of soil. In this study, fly ash and biochar were used together for amelioration of polycyclic aromatic hydrocarbon (PAH) contaminated soil. Field experiment was conducted to investigate the effects of fly ash and biochar on the amelioration of soil PAH, and the yield of Zea mays. The treatments were control, biochar (4 t/ha), fly ash (4 t/ha), ash + biochar ( 2 + 2 t/ha). Soil samples were collected after the harvest of maize crop and analysed for chemical and biological parameters. Thirteen PAHs were analysed in the postharvest soil samples. Soil PAHs were extracted in a microwave oven at 120 °C using hexane : acetone (1:1) mixture. The extracted solutions were concentrated, cleaned and the 13 PAHs [Acenaphthene (Ace), fluorene (Flr), phenanthrene (Phn), anthracene(Ant), pyrene(Pyr), benz(a)anthracene (BaA), chrysene (Chy), benzo(b)fluoranthene (BbF), benzo(k)fluoranthene (BkF), benzo(a)pyrene, benzo(g,h,i)perylene (BghiP), dibenzo(a,h)anthracene, and indeno(1,2,3-cd)pyrene)(Inp)] were analysed using GC-MS. The mean pH increased from 6.09 in control to 6.64 and 6.58 at biochar and fly ash treated soils, respectively. N content was not affected, whereas addition of biochar alone and in combination with fly ash, has significantly increased the soil organic carbon content. P content was almost double in combined (9.06 mg/kg) treatment as compared to control (4.32 mg/kg). The increase in K due to biochar was 118%, whereas char + ash increased soil K by 64%. Soil heavy metals were decreased: Zn (‑48.4%), Ni (‑41.4%), Co (‑36.9%), Cu (‑35.7%), Mn (‑34.3%), Cd (‑33.2%), and Pb (‑30.4%). Soil dehydrogenase activity was significantly increased by ash and biochar treatments and the maximum activity was observed for the

  15. KEY COMPARISON: CCQM-K50: Polycyclic aromatic hydrocarbons (PAHs) in soil/particulate matter

    NASA Astrophysics Data System (ADS)

    Philipp, R.; Bremser, W.; Becker, R.; Win, T.; Schantz, M. M.; Pérez Urquiza, M.; Ávila Calderón, M. A.; Maldonado Torres, M.; Carter, D.; O'Connor, G.; Sejeroe-Olsen, B.; Ricci, M.; Lalere, B.; Peignaux, M.; Kim, D. H.; Itoh, N.; Wong, S.; Man, T. O.; Marques Rodrigues Caixeiro, J.

    2010-01-01

    There are numerous Calibration and Measurement Capability Claims (CMCs) on PAH analysis in various matrices published in the BIPM key comparison database, Appendix C. By July 2007 such CMCs were released in Category 10 Biological fluids and materials, Subcategory 10.4 Tissues, Category 11 Food, Subcategory 11.2 Contaminants and Category 13 Sediments, soils, ores and particulates, Subcategories 13.1 Sediments, 13.2 Soils and 13.4 Particulates. CCQM comparisons are needed to underpin these claims. A pilot study CCQM-P69 'PAHs in soil' was successfully conducted in 2004. After review of the results at the OAWG meeting in September 2005 it was decided to proceed with a key comparison and a concurrent second pilot study CCQM-K50/P69.1. CENAM and BAM agreed to coordinate the intercomparison. The measurand of the study was specified as amount of specific PAHs in solid matrices as extracted under exhaustive extraction conditions. As for the preceding pilot study and two studies for PAHs in solution (CCQM-P31a and CCQM-K38), five target analytes, phenanthrene, fluoranthene, benz[a]anthracene, benzo[a]pyrene and benzo[ghi]perylene, were selected as representative of the measurement of individual compounds. The CCQM-K50 study utilized a soil sample from BAM and an air particulate sample from NIST. Both materials were naturally contaminated, not enriched or spiked. The mass fraction of target analytes in the samples ranged from 2 mg/kg to 15 mg/kg. NIST SRM 1649a Urban Dust was provided as a control material. Participants were requested to determine the mass fraction of the selected PAHs on a dry mass basis and submit a complete uncertainty budget for their measurements. Ten NMIs participated in the study. All participants applied Soxhlet or Accelerated Solvent extraction (ASE) and GC-MS with either deuterated or 13C labelled internal standards. Results demonstrate a good level of equivalence in capabilities of the participating NMIs to identify and measure PAHs in highly

  16. Hydrologic and Water-Quality Responses in Shallow Ground Water Receiving Stormwater Runoff and Potential Transport of Contaminants to Lake Tahoe, California and Nevada, 2005-07

    USGS Publications Warehouse

    Green, Jena M.; Thodal, Carl E.; Welborn, Toby L.

    2008-01-01

    all less than laboratory reporting limits in the deeper sediment sample, but 15 compounds were detected in the uppermost 0.2 foot of sediment. Published concentrations determined to affect benthic aquatic life also were exceeded for copper, zinc, benz[a]anthracene, phenanthrene, and pyrene in the shallow sediment sample. Isotopic composition of water (oxygen 18/16 and hydrogen 2/1 ratios) for samples of shallow ground water, lakewater, and interstitial water from Lake Tahoe indicate the lake was well mixed with a slight ground-water signature in samples collected near the lakebed. One interstitial sample from 0.8 foot beneath the lakebed was nearly all ground water and concentrations of nitrogen and phosphorus were comparable to concentrations in shallow ground-water samples. However, ammonium represented 65 percent of filtered nitrogen in this interstitial sample, but only 10 percent of the average nitrogen in ground-water samples. Nitrate was less than reporting limits in interstitial water, compared with mean nitrate concentration of 750 micrograms per liter in ground-water samples, indicating either active dissimilative nitrate reduction to ammonium by micro-organisms or hydrolysis of organic nitrogen to ammonium with concomitant nitrate reduction. The other interstitial sample falls along a mixing line between ground water and lake water and most of the nitrogen was organic nitrogen.

  17. Areal Distribution and Concentration of Contaminants of Concern in Surficial Streambed and Lakebed Sediments, Lake St. Clair and Tributaries, Michigan, 1990-2003

    USGS Publications Warehouse

    Rachol, Cynthia M.; Button, Daniel T.

    2006-01-01

    were collected throughout the lake. The distribution of trace-element concentrations corresponded well with the results of a two-dimensional hydrodynamic model of flow patterns from the Clinton River into Lake St. Clair. The model was developed independent from the bed sediment analysis described in this report; yet it showed a zone of deposition for outflow from the Clinton River into Lake St. Clair that corresponded well with the spatial distribution of trace-element concentrations. This zone runs along the western shoreline of Lake St. Clair from L'Anse Creuse Bay to St. Clair Shores, Michigan and is reflected in the samples analyzed for mercury and cadmium. Statistical summaries of the concentration data are presented for most contaminants, and selected statistics are compared to effects-based sediment-quality guidelines. Summaries were not computed for dieldrin, chlordane, hexachlorocyclohexane, lindane, and mirex because insufficient data are available for these contaminants. A statistical comparison showed that the median concentration for total DDT, hexachlorobenzene, anthracene, benz[a]anthracene, chrysene, and pyrene are greater than the Threshold Effect Concentration or Lowest Effect Level. Probable Effect Concentration Quotients provide a mechanism for comparing the concentrations of contaminant mixtures against effects-based biota data. Probable Effect Concentration Quotients were calculated for individual samples and compared to effects-based toxicity ranges. The toxicity-range categories used in this study were nontoxic (quotients 0.5). Of the 546 individual samples for which Probable Effect Concentration Quotients were calculated, 469 (86 percent) were categorized as being nontoxic and 77 (14 percent) were categorized as being toxic. Bed-sediment samples with toxic Probable Effect Concentration Quotients were collected from Paint Creek, Galloway Creek, the main stem of the Clinton River, Big Beaver Creek, Red

  18. KEY COMPARISON: Final report on CCQM-K38: Determination of PAHs in solution

    NASA Astrophysics Data System (ADS)

    Duewer, D. L.; May, W. E.; Parris, R. M.; Schantz, M. M.; Wise, S. A.; Piechotta, C.; Philipp, R.; Win, T.; Avila, M.; Pérez Urquiza, M.; Ulberth, F.; Kim, B.; Ishikawa, K.; Chen, D.; Krylov, A. I.; Kustidov, Y. A.; Lopushanskaya, E. M.

    2009-01-01

    Solutions of known mass fraction of organic analytes of interest are typically used to calibrate the measurement processes used in the determination of these analytes. Appropriate value assignments and uncertainty calculations for these calibration solutions are critical. For the Mutual Recognition Arrangement (MRA) developed by the CIPM, there are numerous Calibration and Measurement Capability Claims (CMCs) published in Category 3 Organic Solutions in the CIPM MRA Appendix C. Additional CMCs in this category are being proposed and reviewed. Evidence of successful participation in formal, relevant international comparisons is needed to support these claims. A CCQM pilot study conducted in 2004 was comprised of three parts: CCQM-P31a Organic Solution—Polycyclic Aromatic Hydrocarbons (PAHs), CCQM-P31b Organic Solution—Polychlorinated Biphenyl (PCB) Congeners, and CCQM-P31c Organic Solution—Chlorinated Pesticides. The results from the CCQM-P31a study are summarized below for the PAHs. After review of the P31a results at the April 2004 Organic Analytical Working Group (OAWG) meeting (Sèvres 2004) and the October 2004 OAWG meeting (Beijing 2004), it was decided to proceed with a key comparison study for PAHs in solution (CCQM-K38) with a concurrent second pilot study for the PAHs in solution (CCQM-P31a.1). CCQM-K38 was conducted during the same time period as a PAHs in soil pilot study (CCQM-P69) coordinated by CENAM and BAM. This Key Comparison study demonstrated a high level of equivalence in capabilities of the participating NMIs to successfully identify and measure five PAHs (phenanthrene, fluoranthene, benz[a]anthracene, benzo[a]pyrene, and benzo[ghi]perylene) in a solution using GC/MS-based methods. The PAHs measured in CCQM-K38 were selected to be representative of PAHs typically used as calibrants in the determination of the PAHs found in environmental samples and to provide the typical analytical measurement challenges encountered in the value