Quantification and source identification of atmospheric particulate polycyclic aromatic hydrocarbons and their dry deposition fluxes at three sites in Salvador Basin, Brazil, impacted by mobile and stationary sources

The present work has aimed to determine the 16 US EPA priority PAH atmospheric particulate matter levels present in three sites around Salvador, Bahia: (i) Lapa bus station, strongly impacted by heavy-duty diesel vehicles; (ii) Aratu harbor, impacted by an intense movement of goods, and (iii) Bananeira village on Maré Island, a non vehicle-influenced site with activities such as handcraft work and fisheries. Results indicated that BbF (0.130-6.85 ng m-3) is the PAH with highest concentration in samples from Aratu harbor and Bananeira and CRY (0.075-6.85 ng m-3) presented higher concentrations at Lapa station. PAH sources from studied sites were mainly of anthropogenic origin such as gasoline-fueled light-duty vehicles and diesel-fueled heavy-duty vehicles, discharges in the port, diesel burning from ships, dust ressuspension, indoor soot from cooking, and coal and wood combustion for energy production.

Electrochemical and photocatalytic reactions of polycyclic aromatic hydrocarbons investigated by raman spectroscopy

This paper presents the study of photochemical behavior of polycyclic aromatic hydrocarbons (PAHs), potential pollutants in secondary reactions in aerosols, through Raman spectroscopy compared with its electrochemical behavior. The PAHs studied include pyrene, anthracene, phenanthrene and fluorene. These were adsorbed onto TiO2 and irradiated with ultraviolet light (254 nm). Their electrochemical oxidation was studied by in situ Surface-enhanced Raman Scattering (SERS) and led to the formation of carbonyl-containing products. Oxidized intermediates bearing the C=O group were also formed during photodegradation. The joint analysis of the photodegradation data with those produced by electrochemical means - using spectroscopic techniques for the identification and characterization of the products - revealed the formation of identical products for anthracene, but not for pyrene. A reasonable explanation for this difference in results is that photochemical and electrochemical oxidation reactions proceed via different mechanisms. While photocatalytic degradation over TiO2 is initiated by hydroxyl radicals, electrochemical oxidation is initiated by the direct electron transfer from adsorbed PAH to the electrode, generating PAH cation radicals that undergo subsequent reactions.

Effect of terbium(III) on the binding of aromatic guests with sodium taurocholate aggregates

The effect of binding Tb(3+) to sodium taurocholate aggregates containing polyaromatic hydrocarbon guests was examined using pyrene and 1-ethylnaphthalene as guests that bind to the primary aggregate, and 1-naphthyl-1-ethanol as a secondary aggregate guest. Time-resolved fluorescence quenching studies were used to study the binding site properties, while laser flash photolysis quenching studies provided information on the dynamics of the guest-aggregate system. Both the primary and secondary aggregate binding sites became more compact in the presence of bound Tb(3+), while only the primary aggregate became more accessible to anionic molecules. The binding dynamics for the guest-primary aggregate system became faster when Tb(3+) was bound to the aggregate. In contrast, for the guest-secondary aggregate the presence of Tb(3+) resulted in a small decrease in the dissociation rate constant. The influence of bound Tb(3+) on the primary and secondary bile salt aggregates is significantly different, which affects how these aggregates can be used as supramolecular host systems to modify guest reactivity.

Changes in optical properties caused by UV-irradiation of aquatic humic substances from the amazon river basin: Seasonal variability evaluation

Aquatic humic substances (AHS) isolated from two characteristic seasons of the Negro river, winter and summer corresponding to floody and dry periods, were structurally characterized by (13)C nuclear magnetic ressonance. Subsequently, AHS aqueous solutions were irradiated with a polychromatic lamp (290-475 nm) and monitored by its total organic carbon (TOC) content, ultraviolet-visible (UV-vis) absorbance, fluorescence and Fourier transformed infrared spectroscopy (FTIR). As a result, a photobleaching upto 80% after irradiation of 48 h was observed. Conformational rearrangements and formation of low molecular complexity structures were formed during the irradiation, as deduced from the pH decrement and the fluorescence shifting to lower wavelengths. Additionally a significant mineralization with the formation Of CO(2), CO, and inorganic carbon compounds was registered, as assumed by TOC losses of up to 70%. The differences in photodegradation between samples expressed by photobleaching efficiency were enhanced in the summer sample and related to its elevated aromatic content. Aromatic structures are assumed to have high autosensitization capacity effects mediated by the free radical generation from quinone and phenolic moieties.

Involvement of oxidative stress in the hepatotoxicity induced by aromatic antiepileptic drugs

The use of the classic aromatic antiepileptic drugs (AAEDs) has recently been expanded to a broad spectrum of psychiatric and neurological disorders. However, the clinical use of these drugs is limited by several adverse effects, mainly idiosyncratic hepatotoxicity. AAED-induced hepatotoxicity has been attributed to a defective detoxification by the epoxide hydrolase and accumulation of arene oxides. The underlying mechanism has been proposed as immune-mediated, but direct toxicity has also been suggested. In general, idiosyncratic drug-induced hepatotoxicity may be mediated, at least in part, by oxidative stress. On the other hand, the oxidative stress induced by the AAED metabolites has not been demonstrated yet. Therefore, in the present study we have evaluated the induction of oxidative stress by three classical AAEDs: carbamazepine. phenytoin and phenobarbital as well as by their metabolites. The toxic effects of the metabolites were evaluated by incubating the drug with rat liver microsomes. The AAED-induced oxidative stress was demonstrated by the increased malondialdehyde levels, oxidation of cardiolipin; oxidation of sulfhydryl proteins and alteration of the cellular redox status. Results suggest that the hepatotoxicity associated with AAED might be mediated by the oxidative stress induced by the drugs metabolites. (C) 2008 Elsevier Ltd. All rights reserved

Photoreactions of n-alkyl-3-nitrophenyl ethers with aromatic amines in SDS micelles: A laser flash photolysis study

The quenching of the triplet state of three n-alkyl 3-nitrophenyl ethers: 3-nitroanisol (3-NA), n-butyl 3-nitrophenyl ether (3-NB) and n-decyl 3-nitrophenyl ether (3-ND) by four aniline derivatives: aniline (AN), N,N-dimethylaniline (DMA), 2,4,6-trimethylaniline (TMA), and 4-tetradecylaniline (TDA), was investigated in aqueous micellar SDS solutions by laser flash photolysis. The transient absorption spectra for 3-NA and 3-NB reveal the formation of long-lived intermediate species in the presence of all four quenchers. while for 3-ND no amine-induced intermediates are observed. Comparison of the transient absorption spectra of the probe 3-NA in the presence of DMA in aqueous and micellar solutions shows that the intermediate species are favored by the SDS micelles. With DMA and TMA as quenchers the intermediates are suggested to be the ion radicals generated by single electron transfer from the amine to the probe in the triplet excited state. For the quenchers AN and TDA, the intermediates may be a-complexes. The relative quenching efficiencies generally decrease as the affinity of the quencher for the micellar phase (AN < DMA < TMA < TDA) increases and the mobility of the excited probe (3-NA > 2-NB) decreases. (C) 2011 Elsevier B.V. All rights reserved.

Lorneamides A and B: Two new aromatic amides from a southern Australian marine actinomycete

A marine actinomycete (MST-MA190) isolated from a sample of beach sand collected near Lorne on the southwest coast of Victoria, Australia, has yielded two new aromatic amides, lorneamide A (1) and lorneamide B (2). The lorneamides belong to a novel class of tri-alkyl-substituted benzenes, and their structures were determined by spectroscopic methods.

Partitioning of polycyclic aromatic hydrocarbons in the hair-air system

Partitioning behavior of PAHs including NAP, FLO, PHE, and PYR was investigated. A plot of experimental K-HA against log K-OW gives a good linear relationship. A somewhat similar slope and intercept it-as obtained for the hair-air system using PCB values from the literature. In comparison to K-VA values from the literature, lower values for K-VA were obtained. This may be attributed from differences in species and degradability across biota groups. K-HLA also exhibits good linear relationships with K-OA and other physical chemical properties such as W The lipid fraction has a strong influence on bioconcentration in hair from the air and water. However, hair treatments, hair length, growth dilution, photodegradation, biodegradation, temperature, seasonal variations, wet and dry depositions could alter the degree of bioconcentration of PAHs in the hair.

Metabolic activation of aromatic amines by human pancreas

Epidemiologic studies have suggested that aromatic amines (and nitroaromatic hydrocarbons) may be carcinogenic for human pancreas, Pancreatic tissues from 29 organ donors (13 smokers, 16 non-smokers) were examined for their ability to metabolize aromatic amines and other carcinogens, Microsomes showed no activity for cytochrome P450 (P450) 1A2-dependent N-oxidation of 4-aminobiphenyl (ABP) or for the following activities (and associated P450s): aminopyrine N-demethylation and ethylmorphine N-demethylation (P450 3A4); ethoxyresorufin O-deethylation (P450 1A1) and pentoxyresorufin O-dealkylation (P450 2B6); p-nitrophenol hydroxylation and N-nitrosodimethylamine N-demethylation (P450 2E1); lauric acid omega-hydroxylation (P450 4A1); and 4-(methylnitrosamino)-1-(3-pyridyl-1-butanol) (NNAL) and 4-(methylnitrosamino)1-(3-pyridyl)-1-butanone (NNK) alpha-oxidation (P450 1A2, 2A6, 2D6). Antibodies were used to examine microsomal levels of P450 1A2, 2A6, 2C8/9/18/19, 2E1, 2D6, and 3A3/ 4/5/7 and epoxide hydrolase. Immunoblots detected only epoxide hydrolase at low levels; P450 levels were <1% of liver. Microsomal benzidine/prostaglandin hydroperoxidation activity was low. In pancreatic cytosols and microsomes, 4-nitrobiphenyl reductase activities were present at levels comparable to human liver. The O-acetyltransferase activity (AcCoA-dependent DNA-binding of [H-3]N-hydroxy-ABP) of pancreatic cytosols was high, about two-thirds the levels measured in human colon. Cytosols showed high activity for N-acetylation of p-aminobenzoic acid, but not of sulfamethazine, indicating that acetyltransferase-1 (NAT1) is predominantly expressed in this tissue. Cytosolic sulfotransferase was detected at low levels. Using P-32-post-labeling enhanced by butanol extraction, putative arylamine-DNA adducts were detected in most samples. Moreover, in eight of 29 DNA samples, a major adduct was observed that was chromatographically identical to the predominant ABP-DNA adduct, N-(deoxyguanosin-8-yl)-ABP. These results are consistent with a hypothesis that aromatic amines and nitroaromatic hydrocarbons may be involved in the etiology of human pancreatic cancer.

A study of the vacuum gamma-radiolysis of two aromatic polyimide fluoropolymers containing phenylphosphine oxide

The vacuum gamma -radiolysis of two fluorinated polyimides containing phenylphosphine oxide units, TOR-RC and TOR-RC ODPA, have been studied at 77 K and 300 K. The phenyl phosphine oxide units provide protection of the polymers towards oxidation by oxygen atoms and the bulky fluoromethyl groups reduce the colouration of the polymers by limiting donor-acceptor complex formation through the aromatic units. At 77 K the radicals formed were identified to be a mixture of neutral radicals (60%) and anion radicals. At 300 K only neutral radicals were found. The G-values for radical formation were found to be 0.50 and 0.42 at 77 K and 0.051 and 0.052 at 300 K for TOR-RC and TOR-RC ODPA, respectively. Little change was observed in the visible spectra of the polyimides following vacuum radiolysis at 300 K up to a dose of 3.3 MGy, and the polymers were shown to undergo net cross linking with a gel dose of 0.45 MGy.

A study of the oxidation of two aromatic polyimide fluoropolymers containing phenylphosphine oxide by a water plasma and gamma-radiolysis in air

The oxidation of two fluorinated polyimides containing phenylphosphine oxide units, TOR-RC and TOR-RC ODPA, have been studied at 300 K for treatment by a water plasma and gamma -radiolysis in air. The changes in the O 1s/C 1s ratios obtained from x-ray photoelectron spectroscopy (XPS) analysis showed that for exposure to the water plasma the ratio increases at short exposure times and then levels to a constant value. Evidence for the formation of phosphate species was also obtained from the XPS analyses. Similar observations were made for gamma -radiolysis of the polymers in air. The polymers containing phenylphosphine oxide were found to be more resistant to oxidation in the water plasma than Kapton(R). Radiolysis of the polymers in air to high doses were also accompanied by a red shift in the visible absorption spectra.

An ESR study of the gamma radiolysis of aromatic polyesters containing isomeric naphthalene links

Six polyesters were synthesised from 4,4 ' -oxy-bis(benzoyl chloride) and 1,4-, 1,5-, 1,6-, 2,3-, 2,6-, and 2,7-naphthalenediol isomers. The structures of the polyesters were characterised by means of IR, inherent viscosities in tetrachloroethane (TCE), solutions at 303 K and thermal analysis. The glass transition temperatures were in the range of 425-494 K by DSC thermal analysis. All of the polyesters were irradiated in an AECL Gammacell 220 unit at a dose rate of approximately 6.7 kGy/h to doses in the range of 0-15 kGy at 77 and 300 K. ESR spectroscopy was used to examine the radicals formed during radiolysis and to measure their yields. The G-values for radical formation in the polyesters were found to be in the range 0.18-1.41 at 77 K and 0.19-0.78 at 300 K. At 77 K, up to 15% of the radicals formed on radiolysis were found to be photo-bleachable anion radicals. Annealing experiments were carried out in order to identify the neutral radicals, which were assigned to naphthyl- or phenyl- and phenoxyl-type radicals. (C) 2001 Elsevier Science Ltd. All rights reserved.

Lipophilic methotrexate conjugates with glucose-lipoamino acid moieties: Synthesis and in vitro antitumor activity

To obtain methotrexate (MTX) derivatives with a balanced hydrolipophilic character, we synthesized a series of conjugates in which the drug was linked to lipoamino acid (LAA)-glucose residues (LAAG-MTX). These conjugates displayed increased solubility in polar media compared with the corresponding LAA-MTX conjugates previously described. In vitro biological testing of LAAG-MTX indicated that the introduction of the sugar moiety decreased the biological activity of these MTX conjugates. The tetradecyl derivative 6b, however, was effective in inhibiting the dihydrofolate reductase activity in vitro and showed an inhibitory effect on human lymphoblastoid cell growth. (C) 2001 Wiley-Liss, Inc.

DNA adducts as a biomarker of polycyclic aromatic hydrocarbon exposure in aquatic organisms: relationship to carcinogenicity

The use of DNA adduct measurement as a biomarker of exposure to polycyclic aromatic hydrocarbons (PAHs) is now well established in ecotoxicology. In particular, DNA adduct levels in aquatic organisms has been found to produce a better correlation with PAH exposure than PAH concentrations in organisms. DNA adducts levels are most commonly determined using the P-32-postlabelling assay which measures total aromatic adducts. The relationship between relative DNA adduct formation and carcinogenicity has been investigated for a number of carcinogenic and non-carcinogenic PAHs using an in vitro system. Our results demonstrate that relatively high levels of DNA adducts can be produced by some non-carcinogenic PAHs, while other non-carcinogenic compounds do not produce detectable adducts. In addition, it has been shown that all carcinogenic PAHs investigated produce DNAadducts and that a relationship exists between relative adduct formation and carcinogenic potency. An investigation of adduct levels in fish liver and crustacean hepatopancreas in Oxley Ck, Brisbane has shown that higher than expected DNA adduct levels were correlated with the presence of carcinogenic and noncarcinogenic PAHs with high relative adduct forming potential.