Occupational exposure of truck drivers to dust and polynuclear aromatic hydrocarbons: a pilot study in Geneva, Switzerland.

The exposure to dust and polynuclear aromatic hydrocarbons (PAH) of 15 truck drivers from Geneva, Switzerland, was measured. The drivers were divided between "long-distance" drivers and "local" drivers and between smokers and nonsmokers and were compared with a control group of 6 office workers who were also divided into smokers and nonsmokers. Dust was measured on 1 workday both by a direct-reading instrument and by sampling. The local drivers showed higher exposure to dust (0.3 mg/m3) and PAH than the long-distance drivers (0.1 mg/m3), who showed no difference with the control group. This observation may be due to the fact that the local drivers spend more time in more polluted areas, such as streets with heavy traffic and construction sites, than do the long-distance drivers. Smoking does not influence exposure to dust and PAH of professional truck drivers, as measured in this study, probably because the ventilation rate of the truck cabins is relatively high even during cold days (11-15 r/h). The distribution of dust concentrations was shown in some cases to be quite different from the expected log-normal distribution. The contribution of diesel exhaust to these exposures could not be estimated since no specific tracer was used. However, the relatively low level of dust exposure dose not support the hypothesis that present day levels of diesel exhaust particulates play a significant role in the excess occurrence of lung cancer observed in professional truck drivers.

Biotransformation of aromatic hydrocarbons and organic sulphides by fungi

Toluene is converted to benzyl alcohol by the fungi Mortierella isabellina and Helminthosporium species; in the latter case, the product is further metabolized. Toluene-a -d 1 , toluene-a,a-d2, and toluene-a,a,a-d 3 have been used with Mortierellaisabellina in a series of experiments to determine both primary and secondary deuterium kinetic isotope effects for the enzymic benzylic hydroxylation reaction. The values obtained, intermolecular primary kH/kD = intramolecular p rim a r y kH r kD = 1. 0 2 + O. 0 5, and sec 0 n dar y k H I kD = 1. 37 .:!. 0.05, suggest a mechanism for the reaction involving benzylic proton removal from a radical intermediate in a non-symmetrical transition state. 2H NMR (30.7 MHz) studies using ethylbenzene-l,1-d 2 , 3 -fluoroethylbenzene-l,1-d 2 , 4 -fluoroethylbenzene-l,1-d 2 , and toluene-dB as substrates with Mortierella isabellina suggest, based on the observable differences in rates of conversion between the substrates, that the hydroxylation of hydrocarbons at the benzylic position proceeds via a one electron abstraction from the aromatic ring, giving a radical cation. A series of 1,3-oxathiolanes (eight) were incubated with Mortierella isabellina , Helminthosporium , Rhizopus arrhizus , and Aspergillus niger . Sulphoxides were obtained from Mortierella isabellina and Rhizopus arrhizus using the substrates 2-phenyl-, 2-methyl-2-phenyl-, and 2-phenyl-2-tert. butyl-l,3-oxathiolane. The relative stereochemistry of 2-methyl-2-phenyl-l,3-oxathiolan-l-oxide was assigned based on lH decoupling, n.O.e, 1 and H NMR experiments. The lH NMR (200 MHz) of the methylene protons of 2-methyl-2-phenyl-l,3-oxathiolan-l-oxide was used as a diagnostic standard in assigning the relative stereochemistry of 2-phenyl-l,3-oxathiolan-l-oxide and 2-phenyl-2-tert. butyl-l,3-oxathiolan-l-oxide. The sulphoxides obtained were consistent with an oxidation occurring from the opposite side of the molecule to the phenyl substituent.

Distribution of Polycyclic Aromatic Hydrocarbons in the Cochin Estuary and Backwaters

Department of Chemical Oceanography,Cochin University of Science and Technology

Studies on the effect of Polycyclic Aromatic Hydrocarbons in the life and activity of Perna spp

In the present study an endeavour has been made to analyse the acute toxicity of WAFs of Bombay High crude and Light Diesel oil on commercially important bivalve species Perna viridis and Perna indica by static bioassay methods. The toxic effects of chemicals in the WAF on the organisms ; their tissues and eventually on rate functions have been elucidated. Marine oil pollution not only affects productivity and quality of marine organisms but also eventually affects the health of human population due to a possible health risk by way of consumption of oil contaminated seafood

Uptake Pathways of Polycyclic Aromatic Hydrocarbons in White Clover

An understanding of the primary pathways of plant uptake of organic pollutants is important to enable the risks from crops grown on contaminated soils to be assessed. A series of experiments were undertaken to quantify the importance of the pathways of contamination and the Subsequent transport within the plant using white clover plants grown in solution culture. Root uptake was primarily an absorption process, but a component of the contamination was a result of the transpiration flux to the shoot for higher Solubility compounds. The root contamination can be easily predicted using a simple relationship with K-OW, although if a composition model was used based on lipid content, a significant under prediction of the contamination was observed. Shoot uptake was driven by the transpiration stream flux which was related to the solubility of the individual PAH rather than the K-OW. However, the experiment was over a short duration, 6 days, and models based on K-OW may be better for crops grown in the field where the vegetation will approach equilibrium and transpiration cannot easily be measured, A significant fraction of the shoot contamination resulted from aerial deposition derived from volatilized PAH. This pathway was more significant for compounds approaching log K-OA > 9 and log K-AW < -3. The shoot uptake pathways need further investigation to enable them to be modeled separately, There was no evidence of significant systemic transport of the PAR so transfer outside the transpiration stream is likely to be limited.

Simulating the formation of secondary organic aerosol from the photooxidation of aromatic hydrocarbons

The formation and composition of secondary organic aerosol (SOA) from the photooxidation of benzene, p-xylene, and 1,3,5-trimethylbenzene has been simulated using the Master Chemical Mechanism version 3.1 (MCM v3.1) coupled to a representation of the transfer of organic material from the gas to particle phase. The combined mechanism was tested against data obtained from a series of experiments conducted at the European Photoreactor (EUPHORE) outdoor smog chamber in Valencia, Spain. Simulated aerosol mass concentrations compared reasonably well with the measured SOA data only after absorptive partitioning coefficients were increased by a factor of between 5 and 30. The requirement of such scaling was interpreted in terms of the occurrence of unaccounted-for association reactions in the condensed organic phase leading to the production of relatively more nonvolatile species. Comparisons were made between the relative aerosol forming efficiencies of benzene, toluene, p-xylene, and 1,3,5-trimethylbenzene, and differences in the OH-initiated degradation mechanisms of these aromatic hydrocarbons. A strong, nonlinear relationship was observed between measured (reference) yields of SOA and (proportional) yields of unsaturated dicarbonyl aldehyde species resulting from ring-fragmenting pathways. This observation, and the results of the simulations, is strongly suggestive of the involvement of reactive aldehyde species in association reactions occurring in the aerosol phase, thus promoting SOA formation and growth. The effect of NO, concentrations on SOA formation efficiencies (and formation mechanisms) is discussed.

Superacid-catalyzed polycondensation of acenaphthenequinone with aromatic hydrocarbons

A novel series of linear, high molecular weight polymers were synthesized by one-pot, superacid-catalyzed reaction of acenaphthenequinone (1) with aromatic hydrocarbons. The reactions were performed at room temperature in the Bronsted superacid CF3SO3H (trifluoromethanesulfonic acid, TFSA) and in a mixture of TFSA with methanesulfonic acid (MSA) and trifluoroacetic acid (TFA), which was used as both solvent and a medium for generation of electrophilic species from acenaphthenequinone. The polymer-forming reaction was found to be dependent greatly on the acidity of the reaction medium, as judged from the viscosity of the polymers obtained. Polycondensations of acenaphthenequinone with 4,4'-diphenoxybenzophenone (f), 1,3-bis(4-phenoxybenzoyl)benzene (g), 1,4-bis(4-phenoxybenzoyl)benzene (h), 1,10-bis(4-phenoxyphenyl)decane-1,10-dione (i), 2,6-diphenoxybenzonitrile), 2,6-diphenoxybenzoic acid (k), and 2-(4-biphenylyl)-6-phenylbenzoxazole (1) proceeded in a reaction medium of wide range of acidity, including pure TFSA (Hammett acidity function H-0 of pure TFSA is -14.1), whereas condensation of 1 with biphenyl, terphenyl, diphenyl ether, and 1,4-diphenoxybenzene needed a reaction medium of acidity H-0 less than -11.5. A possible reaction mechanism is suggested. The polymers obtained were found to be soluble in the common organic solvents, and flexible transparent films could be cast from the solutions. H-1 and C-13 NMR analyses of the polymers synthesized revealed their linear, highly regular structure. The polymers also possess high thermostability. Char yields for polymers 3a, 3c, 3d, and 3l in nitrogen were close to 80% at 1000 degrees C.

Improving the Fluorescence Detectability of Polycyclic Aromatic Hydrocarbons for Evaluation of Workplace Environments of Cement Industries Processing Organic Residues

The burning of organic residues and wastes in furnaces of cement industries has been an attractive and lucrative approach to eliminate stocks of these pollutants. There is a potential risk for producing PAH in the workplace of industries burning organic wastes, so that highly sensitive analytical methods are needed for monitoring the air quality of these environments. An official method for determination of PAH is based on liquid chromatography with fluorescence detection at fixed excitation and emission wavelengths. We demonstrate that a suitable choice of these wavelengths, which are changed during the chromatographic run, significantly improves the detectability of PAH in atmosphere and particulate matter collected in cement industries.

Atmospheric particulate polycyclic aromatic hydrocarbons from road transport in southeast Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Polycyclic aromatic hydrocarbons from wood pyrolyis in charcoal production furnaces

Polycyclic aromatic hydrocarbons (PAH) were measured in smoke samples from wood carbonization during charcoal production, in both particulate matter (PM) and gaseous phases. Samples were acquired using a medium-volume air sampler at 1.5 m distance from the furnace. Particle-bound PAH were collected on Fluoropore polytetrafluoroethylene filters and gas-phase PAH were collected into sorbent tubes with XAD-2 resin. PAH were extracted with dichloromethane-methanol and analyzed using gas chromatography-mass spectrometry. The results showed total emission from the furnace of 26 mu g/m(3) for the 16 PAH and 2.8 mu g/m(3) for the 10 genotoxic PAH (from fluoranthene to benzo[g,h,i]perylene). High emission of 16 PAH in the first 8 h of wood carbonization was detected (64 mu g/m(3); 56% of the total emission). Associated with PM, 11% of the total emission of 16 PAH (in both phases) and 60% of 10 genotoxic PAH were found. Relative ratios (for example, [Phe]/[Phe] + [Ant]) for the PAH of the same molecular weight were obtained and compared with the published data. The concentrations of benzo[a]pyrene equivalent (BaPeq) were estimated using the list of toxic equivalent factors suggested by Nisbet and LaGoy, 1992. The values of 0.30 and 0.06 mg/m3 were obtained for the total concentrations of BaPeq in PM and gaseous phase, respectively. (c) 2006 Elsevier B.V. All rights reserved.

Identification of polycyclic aromatic hydrocarbons and methoxylated phenols in wood smoke emitted during production of charcoal

More than 130 organic substances in dichloromethane-methanol (4: 1) extracts of particulate matter and the gaseous phase from wood burning for the production of charcoal have been identified by capillary gas chromatography coupled with low-resolution mass spectrometry (GC-MS), use of GC retention indices, and comparison with authentic standards. Many of the substances identified are methoxyphenols (derivatives of syringol and guaiacol), polycyclic aromatic hydrocarbons (PAH), oxidized PAH (oxy-PAH), and levoglucosan, the last being a monosoccharide derivative from the thermal breakdown of cellulose. The amount of unsubstituted PAH was greater than that of methyl- and dimethyl-substituted homologs.

Screening and confirmation of PAHs in vegetable oil samples by use of supercritical fluid extraction in conjunction with liquid chromatography and fluorimetric detection

A fast, simple, non-destructive method for the direct screening of polycyclic aromatic hydrocarbons (PAHs) in vegetable oil samples is proposed. The method uses a supercritical fluid extraction (SFE) system coupled on-line with a fluorimetric detector to determine PAHs. This special assembly avoids the main problems encountered in the determination of PAHs in complex matrices such as vegetable oils. PAHs are selectively extracted by using silica gel in the thimble and cleaned up by passage through a C18 column. Interferences are preferentially retained by the silica gel during the SFE process while PAHs are adsorbed in the C18 column and the remainder of the matrix is sent to waste. Finally, the C18 column is purged to remove residual CO2 gas and adsorbed PAHs are recovered by desorption with a solvent. The extracts from positive samples are subsequently analyzed by liquid chromatography (LC) with fluorescence detection. The proposed method allows the confirmation of vegetable oil safety and hence provides a new tool for consumer protection. (C) 2004 Elsevier B.V. All rights reserved.

Improving the Fluorescence Detectability of Polycyclic Aromatic Hydrocarbons for Evaluation of Workplace Environments of Cement Industries Processing Organic Residues

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Contamination of cachaca by pahs from storage containers

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