Determination and comparison of nitrated-polycyclic aromatic hydrocarbons measured in air and diesel particulate reference materials

Physical-chemical and microbiological characterization, and mutagenic activity of airborne PM sampled in a biomass-fueled electrical production facility

Biomass combustion is used in heating and electric power generation in many areas of the world. Airborne particulate matter (PM) is released when biomass is brought to a facility, stored, and combusted. Occupational exposure to airborne PM within biomass-fueled facilities may lead to health problems. In March and August of 2006, airborne PM was collected from a biomass-fueled facility located in Denmark. In addition, source-specific PM was generated from straw and wood pellets using a rotating drum. The PM was analyzed for polycyclic aromatic hydrocarbons (PAHs), metals, microbial components, mutagenic activity, and ability to generate highly reactive oxygen species (hROS) in cell-free aqueous suspensions. PM collected from the boiler room and the biomass storage hall had higher levels of mutagenic activity, PAHs and metals, and a higher hROS generating potential than the source specific PM. The mutagenic activity was generally more potent without S9 activation, and on the metabolically enhanced strain YG1041, relative to TA98. Significant correlations were found between mutagenicity on YG1041 (without S9) and PAH concentration and mutagenicity on YG1041 (with S9) and hROS generating ability. PM collected in March was more toxic than PM collected in August. Overall, airborne PM collected from the facility, especially that from the boiler room, were more toxic than PM generated from straw and wood chips. The results suggest that exposure to combustion PM in a biomass-fueled facility, which likely includes PM from biomass combustion as well as internal combustion vehicles, may contribute to an elevated risk of adverse health effects.

Organic extracts of urban air pollution particulate matter (PM2.5)-induced genotoxicity and oxidative stress in human lung bronchial epithelial cells (BEAS-2B cells)

Traffic is a major source of particulate matter (PM), and ultrafine particulates and traffic intensity probably contribute significantly to PM-related health effects. As a strong relationship between air pollution and motor vehicle-originated pollutants has been shown to exist, air pollution genotoxicity studies of urban cities are steadily increasing. In Korea, the death rate caused by lung cancer is the most rapidly increased cancer death rate in the past 10 years. In this study, genotoxicity of PM2.5 (<2.5μm in aerodynamic diameter particles) collected from the traffic area in Suwon City, Korea, was studied using cultured human lung bronchial epithelial cells (BEAS-2B) as a model system for the potential inhalation health effects. Organic extract of PM2.5 (CE) generated significant DNA breakage and micronucleus formation in a dose-dependent manner (1μg/cm(3)-50μg/cm(3)). In the acid-base-neutral fractionation of PM2.5, neutral samples including the aliphatic (F3), aromatic (F4) and slightly polar (F5) fractions generated significant DNA breakage and micronucleus formation. These genotoxic effects were significantly blocked by scavenging agents [superoxide dismutase (SOD), sodium selenite (SS), mannitol (M), catalase (CAT)]. In addition, in the modified Comet assay using endonucleases (FPG and ENDOIII), CE and its fractions (F3, F4, and F5) increased DNA breakage compared with control groups, indicating that CE and fractions of PM2.5 induced oxidative DNA damage. These results clearly suggest that PM2.5 collected in the Suwon traffic area has genotoxic effects and that reactive oxygen species may play a distinct role in these effects. In addition, aliphatic/chlorinated hydrocarbons, PAH/alkylderivatives, and nitro-PAH/ketones/quinones may be important causative agents of the genotoxic effects.

Bioaccumulation of nitroarenes in bivalves at Osaka Bay, Japan

This paper reports for the first time the detection and occurrence of nitroarenes (NPAHs) in marine organisms. Mussels and oysters collected from Osaka Bay, Japan, had total NPAHs concentrations that ranged from 2380 to 24,688 pg/g dry and 2672 to 25,961 pg/g dry, respectively. Relatively higher concentrations were detected in sampling sites located near the central district and suburbs of Osaka City implying that the most probable sources of NPAHs in the two bivalves are exhaust gases and smokes emitted by automobiles and industrial plants. Bivalves had relatively higher residues of 1-nitronaphthalene, 2-nitronaphthalene, 3-nitrophenanthrene, and 9-nitrophenanthrenes. Residues of 2-nitrofluorene, 1-nitropyrene, 4-nitropyrenes, and 6-nitrochrysene were much lower compared to nitronaphthalenes and nitrophenanthrenes. Inter-species differences was only observed for 2-nitronaphthalene with oysters exhibiting significantly higher residues than mussels.

A comparative photophysical and photochemical study of nitropyrene isomers occurring in the environment

Ground state absorption, first excited-singlet state, and properties of reactive intermediates of mononitropyrene isomers encountered in the atmospheric aerosol have been studied under different conditions that could mimic the environment. The nitro group can present different orientations relative to the pyrene ring depending on its geometric location and could induce differences in the photochemistry of the isomers. The 2-NO(2)Py isomer has the largest red shift and lowest oscillator strength in the UV-visible band associated with the nitro group. The isomers show very low fluorescence yields (10(-3)-10(-4)). Only 1-NO(2)Py and 4-NO(2)Py have phosphorescence emission (Φ(p) ≈ 10(-4)), indicating that the lowest triplet state decays mainly through effective radiationless channels. Laser photolysis produces a low-lying triplet state (τ(T) = 10(-5)-10(-6) s), a long-lived pyrenoxy radical, and a PyNO(2)H radical in solvents in which the triplet can abstract a hydrogen atom. Similar triplet yields were calculated (0.1-0.6) for the isomers, while significant differences in the relative yield of the long-lived species were determined. Differences in the quenching rate constants of the triplet by water and phenols suggest a strong hydrogen-bond interaction with the nitro group in the C-2 position, which provides for radiationless deactivation routes.

Primary photochemistry of nitrated aromatic compounds: excited-state dynamics and NO· dissociation from 9-nitroanthracene

We report results of femtosecond-resolved ex-periments which elucidate the time scale for the primary photoinduced events in the model nitroaromatic compound 9-nitroanthracene. Through time-resolved fluorescence measurements, we observed the ultrafast decay of the initially excited singlet state, and through transient absorption experiments, we observed the spectral evolution associated with the formation of the relaxed phosphorescent T(1) state. Additionally, we have detected for the first time the accumulation of the anthryloxy radical which results from the nitro-group rearrangement and NO(•) dissociation from photoexcited 9-nitroanthracene, a photochemical channel which occurs in parallel with the formation of the phosphorescent state. The spectral evolution in this molecule is highly complex since both channels take place in similar time ranges of up to a few picoseconds. Despite this complexity, our experiments provide the general time scales in which the primary products are formed. In addition, we include calculations at the time-dependent density functional level of theory which distinguish the molecular orbitals responsible for the n-π* character of the "receiver" vibronic triplet states that couple with the first singlet state and promote the ultrafast transfer of population between the two manifolds. Comparisons with the isoelectronic compounds anthracene-9-carboxylic acid and its conjugated base, which are highly fluorescent, show that in these two compounds the near-isoenergeticity of the S(1) with an appropriate "receiver" triplet state is disrupted, providing support to the idea that a specific energy coincidence is important for the ultrafast population of the triplet manifold, prevalent in polycyclic nitrated aromatic compounds.

Determining times to maximum urine excretion of 1-aminopyrene after diesel exhaust exposure

Biomonitoring of exposures to toxins is an important tool for monitoring public health and safety. Using this tool, exposures are typically measured by the collection of biological specimens such as blood and urine samples. Urine sampling represents a more convenient and less-invasive alternative to blood sampling; however, less work has been published on methodologies for characterizing the time course of excretion and the determination of the time of maximum excretion from urine samples. This paper compares two methods of characterizing the urine excretion profile and estimating the time of maximum excretion: Non-compartmental analysis versus a non-linear pharmacokinetic (PK) modeling. We examine these methodologies using both simulated data and observed data taken from a recent experiment examining a biomarker of diesel exhaust (DE), urinary 1-aminopyrene (1-AP). In the experiment, a series of spot urine samples were collected in a group of healthy volunteers for 24 h after a controlled DE exposure. Simulated data showed that the use of non-linear modeling techniques to estimate PK parameters was more likely to estimate the true time of maximum excretion compared with the non-compartmental approach. Our analysis of observed concentrations of 1-AP led to a hypothesis that there are two subgroups of subjects in terms of the timing of their 1-AP excretion. Results showed that approximately 63% of the subjects had a median time of maximum excretion of 5.37 h, whereas 30% of the subjects may have had maximum excretion times longer than 24 h.

Temporal variation of nitro-polycyclic aromatic hydrocarbons in PM10 and PM2.5 collected in Northern Mexico City

With the aim to determine the presence of individual nitro-PAH contained in particles in the atmosphere of Mexico City, a monitoring campaign for particulate matter (PM(10) and PM(2.5)) was carried out in Northern Mexico City, from April 2006 to February 2007. The PM(10) annual median concentration was 65.2μgm(-3) associated to 7.6μgm(-3) of solvent-extractable organic matter (SEOM) corresponding to 11.4% of the PM(10) concentration and 38.6μgm(-3) with 5.9μgm(-3) SEOM corresponding to 15.2% for PM(2.5). PM concentration and SEOM varied with the season and the particle size. The quantification of nitro-polycyclic aromatic hydrocarbons (nitro-PAH) was developed through the standards addition method under two schemes: reference standard with and without matrix, the former giving the best results. The recovery percentages varied with the extraction method within the 52 to 97% range depending on each nitro-PAH. The determination of the latter was effected with and without sample purification, also termed fractioning, giving similar results. 8 nitro-PAH were quantified, and their sum ranged from 111 to 819pgm(-3) for PM(10) and from 58 to 383pgm(-3) for PM(2.5), depending on the season. The greatest concentration was for 9-Nitroanthracene in PM(10) and PM(2.5), detected during the cold-dry season, with a median (10th-90th percentiles) concentration in 235pgm(-3) (66-449pgm(-3)) for PM(10) and 73pgm(-3) (18-117pgm(-3)) for PM(2.5). The correlation among mass concentrations of the nitro-PAH and criteria pollutants was statistically significant for some nitro-PAH with PM(10), SEOM in PM(10), SEOM in PM(2.5), NO(X), NO(2) and CO, suggesting either sources, primary or secondary origin. The measured concentrations of nitro-PAH were higher than those reported in other countries, but lower than those from Chinese cities. Knowledge of nitro-PAH atmospheric concentrations can aid during the surveillance of diseases (cardiovascular and cancer risk) associated with these exposures.

Mutagenicity of airborne particulates assessed by salmonella assay and the SOS chromotest in Wrocław, Poland

Ambient air particulate matter less than 2.5 microm in aerodynamic diameter (PM(2.5)) samples were collected during summer and autumn using a Staplex high-volume air sampler. They were later extracted with dichloromethane in a Soxhlet apparatus. Polyaromatic hydrocarbon (PAH) content in extracts was determined by the high-performance liquid chromatography technique using fluorescence detection, whereas the nitro-PAH content was determined by gas chromatography using mass detection. Four Salmonella typhimurium strains (TA98, TA100, YG1041, and YG1042) were used in assays conducted with and without metabolic activation. The extracts were also tested with the SOS chromotest supplied by Environmental Biodetection Products Incorporated. The obtained results confirmed the Salmonella assay and the SOS chromotest usability for the purpose of atmospheric pollution monitoring within an urban agglomeration. The atmospheric pollution extracts under examination differed among each other regarding total content and percentage of individual compounds, depending on the season of sampling. The highest total PAH content and the highest nitro-PAH content in the tested samples as well as the most extensive range of detected compounds were found in the autumn season (heating season). The highest mutagenicity was noted for PM(2.5) samples collected in autumn. The high values of mutagenicity ratios and induction factors were obtained from assays carried out with and without metabolic activation, which is an argument for the presence of promutagens and direct mutagens. The YG1041 strain proved to be the most effective in detection of mutagenicity of the suspended dust extracts because of its notably high sensitivity to nitro-aromatic compounds. The SOS chromotest was very sensitive to a large spectrum of genotoxic air pollutants and showed a high degree of similarity with the results of the Salmonella assay. In comparison with the frequently used Ames test, the SOS chromotest enables quick analysis of the genotoxic effects of samples using only one tester strain. In addition, its miniaturized design decreases the consumption of tested samples.

Detection of DNA damage in fish Oreochromis mossambicus induced by co-exposure to phenanthrene and nitrite by ESI-MS/MS

BACKGROUND, AIM, AND SCOPE

Mutagenic nitrated polycyclic aromatic hydrocarbons (nitro-PAHs) have been known to arise in the environment through direct emissions from combustion sources and nitration of PAHs, primarily in the atmosphere. In the marine environment, PAHs are one of the classic anthropogenic organic pollutants, while nitrite (NO(2)(-)) is produced naturally via various biological processes like imbalance in nitrification/denitrification or eutrophication and subsequent oxygen depletion from an oversupply of nutrients. In this paper, we report the formation of PAH-DNA adducts in fish contaminated with PAHs and exposed to NO(2)(-) in the ambient water. Electrospray ionization tandem mass spectrometric (ESI-MS/MS) analysis of the bile of the euryhaline fish Oreochromis mossambicus exposed simultaneously to field relevant sublethal concentrations of phenanthrene and NO(2)(-) and collision-induced dissociation of selected ions revealed the presence of DNA-PAH adducts. The present study indicates that, although several high sensitivity techniques have been developed for the analysis of PAH derived DNA adducts, MS/MS has emerged as a powerful tool in the detection and structure elucidation of DNA adducts.

MATERIALS AND METHODS

Juvenile O. mossambicus from a local estuarine fish farm were used with increasing frequency for carcinogenicity testing and comparative cancer research. The fish were exposed to the alkylating agent phenanthrene in the presence of NO(2)(-). Composite untreated bile samples after dilution with methanol: water (1:1; v/v) were analyzed by ESI-MS.

RESULTS

Several adducts could be evidenced in the bile by MS/MS. Deoxyadenosine/deoxyguanosine having a mass in the range of 450-650 amu is detected. In addition, a segment of modified dinucleotide with a mass that corresponds to a dimer consisting of a modified guanosine and a normal guanosine has also been identified in the bile.

DISCUSSION

The formation of certain types of DNA adducts is a crucial step in the induction of cancer and a primary stage in mutagenesis. Phenanthrene injected by i.p. route led to the transformation of phenanthrene to N-formyl amino phenanthrene-N(6)-deoxyadenosine adduct, whereas the fish co-exposed to phenanthrene and ambient nitrite metabolizes PAH to mono-, di- as well as trinitro derivatives, which then react with DNA leading to the formation of mainly modified guanosine and adenosine adducts. In the present investigation, dinitrophenanthrene diol epoxide (DNPDE) adduct with guanosine (m/z 587) seems to be the dominant adduct in the mixture, and its presence is shown first as a comparatively less stable adduct, which decomposes to give a more stable N(2) adduct (m/z 567).

CONCLUSIONS

MS/MS has proved to be useful in the rapid determination and discrimination of structurally different phenanthrene/derivatives DNA adducts in a complex mixture of fish bile co-exposed to phenanthrene and nitrite. However, the nature of metabolites formed is likely determined by the route of PAH administration, and there is a need to further define the early biochemical events of carcinogenesis in these species.

RECOMMENDATIONS AND PERSPECTIVES

DNA adduct analysis in fish bile offers a promising approach to study the risk of potentiation of anthropogenic chemicals into genotoxic compounds in the presence of nitrite in the marine environment. We believe this is the first report on the formation of DNA-phenanthrene adducts on co-exposure of the fish to PAH and nitrite.

Exposures to particulate air pollution and nitro-polycyclic aromatic hydrocarbons among taxi drivers in Shenyang, China

Exposures to particulate matter (PM) of both 10-2.5 microm (PM(10-2.5)) and below 2.5 microm (PM(2.5)) were measured for a cohort of taxi drivers in Shenyang, China, during August 2007. PM samples were collected inside and outside the taxi during the drivers' workshifts, and also inside the drivers' homes when they were off-shift. Ambient PM samples were also collected at a stationary location in Shenyang. Elemental carbon (EC) and organic carbon (OC) were also measured in PM collected on quartz filters inside the taxis as well as at the stationary site. Concentrations of three nitro-polycyclic aromatic hydrocarbons (NPAHs), 1-nitropyrene (1NP), 2-nitropyrene (2NP), and 2-nitrofluoranthene (2NFl), were determined in extracts of the PM samples by using a 2D-HPLC-MS/MS method. The 2NP and 2NFl concentrations did not change substantially with sampling location, but the 1NP concentrations were much higher in samples collected inside and outside the taxis as compared with sampling locations that were more removed from traffic. Concentration ratios of specific NPAHs were used to assess the atmospheric conditions in Shenyang during the sampling period. The relatively high ratios of 2NFl/1NP ( approximately 8-50) indicate an important contribution from secondary NPAH formation to ambient NPAH levels, especially for the nontaxi samples. The ratios of 2NFl/2NP (2.5-4.3) indicate that 2NFl is primarily formed via the hydroxyl-initiated reaction.

Genetic biomonitoring of an urban population exposed to mutagenic airborne pollutants

Biomonitoring studies have increased as a consequence of risks and effects to human health on exposure to environmental contaminants, mainly air pollutants. Genetic biomarkers are useful tools for the early assessment of exposure to occupational and environmental pollution. The objective of the present study was to investigate genotoxic effects on people residing and/or working downwind from an oil refinery in southern Brazil and the mutagenic activity of airborne particulate matter (PM10). Samples of peripheral blood and buccal mucosa cells were evaluated using the single-cell gel electrophoresis assay (comet assay) and the micronucleus (MN) assay, respectively. PM10 samples were collected in the target site and the organic matter extraced with dichloromethane was assessed for mutagenic activity in the Salmonella/microsome assay. The exposed group (n=37) was compared to a reference group (n=37) of subjects living in an urban area with limited traffic and industrial influence, located far from the main industrial areas. All PM10 organic extracts showed mutagenic positive responses and the effect decreased in the presence of S9 mix indicating that the predominant compounds present were direct-acting mutagens. The responses of YGs strains are consistent with aromatic amines and nitroarenes being present in the PM10 extracts. The group in the area under the influence of the oil refinery (exposed group) showed significantly higher DNA damage in lymphocytes than the reference group. The MN frequencies in buccal mucosa were very low for both groups and no difference between groups was observed. No association was found between age and tobacco smoking habit and level of DNA damages measured by the comet assay. The results indicate that the comet assay was a sensitive tool to detect DNA damage in subjects under the influence of an oil refinery, with marked genotoxic activity in the atmospheric environment.

Influence of combustion temperature on formation of nitro-PAHs and decomposition and removal behaviors in pilot-scale waste incinerator

To gain a better understanding of the formation and decomposition behaviors of nitro-polycyclic aromatic hydrocarbons (nitro-PAHs) in solid waste combustion, incineration experiments were conducted using a pilot-scale incinerator. Nitro-PAHs were formed during primary combustion, although the amounts formed were several orders of magnitude lower than those of the PAHs, PCDD/Fs, and the dioxin-like PCBs. Increasing the temperature of primary combustion from 690 to 890 degrees C resulted in a significant decrease in the formation of most of the nitro-PAH compounds studied. More than 99% of nitro-PAHs formed in the primary combustion zone were decomposed in the secondary combustion chamber at 900 degrees C with a 3-s residence time. The results indicate that appropriate secondary combustion conditions are the key to controlling emissions of nitro-PAHs. Under optimized conditions, the amounts of nitro-PAHs in the final off gases and in the ashes were significantly lower than those present in the incinerator input. Overall destruction efficiencies of nitro-PAHs reported in this study were 95.81-98.33%, indicating that emission of nitro-PAHs from solid waste combustion can be minimized by appropriate combustion control.

Quantification of 1-aminopyrene in human urine after a controlled exposure to diesel exhaust

Diesel exhaust (DE) is a significant source of air pollution that has been linked to respiratory and cardiovascular morbidity and mortality. Many components in DE, such as polycyclic aromatic hydrocarbons, are present in the environment from other sources. 1-Nitropyrene appears to be a more specific marker of DE exposure. 1-Nitropyrene is partially metabolized to 1-aminopyrene and excreted in urine. We developed a practical, sensitive method for measuring 1-aminopyrene in human urine using a HPLC-fluorescence technique. We measured 1-aminopyrene concentrations in spot urine samples collected prior to and during 24 h following the start of 1 h controlled exposures to DE (target concentration 300 microg m(-3) as PM(10)) and clean air control. Time-weighted-average concentrations of urinary 1-aminopyrene were significantly greater following the DE exposure compared to the control (median 138.7 ng g(-1) creatinine vs. 21.7 ng g(-1) creatinine, p < 0.0001). Comparing DE to control exposures, we observed significant increases in 1-aminopyrine concentration from pre-exposure to either first post-exposure void or peak spot urine concentration following exposure (p = 0.027 and p = 0.0026, respectively). Large inter-individual variability, in both the concentration of urinary 1-aminopyrene and the time course of appearance in the urine following the standardized exposure to DE, suggests the need to explore subject variables that may affect conversion of inhaled 1-nitropyrene to urinary excretion of 1-aminopyrene.

Genotoxicity of 3-nitrobenzanthrone and 3-aminobenzanthrone in MutaMouse and lung epithelial cells derived from MutaMouse

FE1 lung epithelial cells derived from MutaMouse are a new model system to provide in vitro mutagenicity data with the potential to predict the outcome of an in vivo MutaMouse test. 3-Nitrobenzanthrone (3-NBA) is a potent mutagen and suspected human carcinogen identified in diesel exhaust and urban air pollution. We investigated the mutagenicity and DNA binding of 3-NBA and its main metabolite 3-aminobenzanthrone (3-ABA) in vitro and in vivo in the MutaMouse assay. Mice were treated with 3-NBA or 3-ABA (0, 2 or 5 mg/kg body weight/day) by gavage for 28 days and 28 days later lacZ mutant frequency (MF) was determined in liver, lung and bone marrow. For both compounds, dose-related increases in MF were seen in liver and bone marrow, but not in lung; mutagenic activity was approximately 2-fold lower for 3-ABA than for 3-NBA. With 3-NBA, highest DNA adduct levels (measured by (32)P-post-labelling) were found in liver (approximately 230 adducts per 10(8) nucleotides) with levels 20- to 40-fold lower in bone marrow and lung. With 3-ABA, DNA adduct levels were again highest in the liver, but approximately 4-fold lower than for 3-NBA. FE1 cells were exposed to up to 10 microg/ml 3-NBA or 3-ABA for 6 h with or without exogenous activation (S9) and harvested after 3 days. For 3-NBA, there was a dose-related increase in MF both with and without S9 mix, which was >10 times higher than observed in vivo. At the highest concentration of 3-ABA (10 microg/ml), we found only around a 2-fold increase in MF relative to controls. DNA adduct formation in FE1 cells was dose-dependent for both compounds, but 10- to 20-fold higher for 3-NBA compared to 3-ABA. Collectively, our data indicate that MutaMouse FE1 cells are well suited for cost-effective testing of suspected mutagens with different metabolic activation pathways as a guide for subsequent in vivo MutaMouse testing.

Tumorigenicity and genotoxicity of an environmental pollutant 2,7-dinitrofluorene after systemic administration at a low dose level to female rats

Environmental pollution with nitroaromatic compounds may pose health hazards. We have examined the tumorigenicity in female Sprague-Dawley rats of 2,7-dinitrofluorene (2,7-diNF) and 9-oxo-2,7-diNF administered by intraperitoneal (i.p.) and oral routes at 10 micromol/kg body weight, 3 times per week for 4 weeks. After i.p. treatment, the estimated median latency for the combined malignant and benign mammary tumors was decreased in 2,7-diNF- (p = 0.003) or 9-oxo-2,7-diNF-treated (p = 0.007), relative to vehicle-treated rats (42 or 64 vs. 80 weeks, respectively), whereas after oral dosing, there were no significant differences. At 90 weeks, the malignant mammary tumor incidence in 2,7-diNF-, 9-oxo-2,7-diNF- and vehicle-i.p. treated rats was 44 (p = 0.02 vs. vehicle-treated), 25 and 6%, respectively. Liver and mammary gland DNA was analyzed by HPLC combined with electrospray tandem mass spectrometry for the presence of a deoxyguanosine (dG-2,7-diNF) adduct and a deoxyadenosine (dA-2,7-diNF) adduct derived from 2,7-diNF, and a deoxyguanosine (dG-9-oxo-2,7-diNF) adduct derived from 9-oxo-2,7-diNF. Both dG-2,7-diNF and dA-2,7-diNF were detected in DNA of 2,7-diNF-treated rats, whereas only very low levels of dG-9-oxo-2,7-diNF were detected in DNA of 9-oxo-2,7-diNF-treated rats. After i.p. treatment, the dA-2,7-diNF level was higher (p < 0.01) in the mammary gland than liver (13.6 vs. 7.8 adducts/10(8) nucleotides). In the mammary gland, the dG-2,7-diNF level was higher (p < 0.05) after i.p. than oral dosing and also higher (p < 0.05) than in the liver (36 vs. 8.6 and vs. 9.1 adducts/10(8) nucleotides, respectively). The preferential display of carcinogenicity and genotoxicity in the mammary gland by low doses of 2,7-diNF signifies its potential relevance for environmental breast cancer.

Characterisation of solvent extractable organic constituents in atmospheric particulate matter: an overview

In spite of accounting for 10-70% of the atmospheric aerosol mass, particulate-phase organic compounds are not well characterised, and many aspects of aerosol formation and evolution are still unknown. The growing awareness of the impact of particulate aerosols on climate, and the incompletely recognised but serious effects of anthropogenic constituents on air quality and human health, have conducted to several scientific studies. These investigations have provided information about the behaviour of atmospheric particulate matter and the description of the character of its carbonaceous content. The compilation of such results is important as they append to the emergent global-wide dataset of the organic composition of atmospheric aerosols. The contribution of the major emission sources to regional particulate pollution can be diagnosed by using specific molecular markers. This overview is mainly focused on results obtained with gas chromatography coupled with mass spectrometry, since it is the analytical method of choice in elucidating the solvent-extractable organic compounds in atmospheric particulate matter. A synopsis of the selection of organic tracers and the application of geochemical parameters to the analysis of organic constituents as a tool for source apportionment is shown here. Besides the assessment of current knowledge, this paper also presents the identification of further areas of concern.

Mutagenicity and DNA adduct formation of PAH, nitro-PAH, and oxy-PAH fractions of atmospheric particulate matter from São Paulo, Brazil

Urban particulate matter (UPM) contributes to lung cancer incidence. Here, we have studied the mutagenic activity and DNA adduct-forming ability of fractionated UPM extractable organic matter (EOM). UPM was collected with a high-volume sampler in June 2004 at two sites, one at street level adjacent to a roadway and the other inside a park within the urban area of the city of São Paulo, Brazil. UPM was extracted using dichloromethane, and the resulting EOM was separated by HPLC to obtain PAH, nitro-PAH, and oxy-PAH fractions which were tested for mutagenicity with the Salmonella strains TA98 and YG1041 with and without S9 metabolic activation. The PAH fraction from both sites showed negligible mutagenic activity in both strains. The highest mutagenic activity was found for the nitro-PAH fraction using YG1041 without metabolic activation; however, results were comparable for both sites. The nitro-PAH and oxy-PAH fractions were incubated with calf thymus DNA under reductive conditions appropriate for the activation of nitro aromatic compounds, then DNA adduct patterns and levels were determined with thin-layer chromatography (TLC) 32P-postlabeling method using two enrichment procedures-nuclease P1 digestion and butanol extraction. Reductively activated fractions from both sites produced diagonal radioactive zones (DRZ) of putative aromatic DNA adducts on thin layer plates with both enrichment procedures. No such DRZ were observed in control experiments using fractions from unexposed filters or from incubations without activating system. Total adduct levels produced by the nitro-PAH fractions were similar for both sites ranging from 30 to 45 adducts per 10(8) normal nucleotides. In contrast, the DNA binding of reductively activated oxy-PAH fractions was three times higher and the adduct pattern consisted of multiple discrete spots along the diagonal line on the thin layer plates. However, DNA adduct levels were not significantly different between the sampling sites. Both samples presented the same levels of mutagenic activity. The response in the Salmonella assay was typical of nitroaromatics. Although, more mutagenic activity was related to the nitro-PAH fraction in the Salmonella assay, the oxy-PAH fractions showed the highest DNA adduct levels. More studies are needed to elucidate the nature of the genotoxicants occurring in São Paulo atmospheric samples.

Analysis of 1-nitropyrene in air particulate matter standard reference materials by using two-dimensional high performance liquid chromatography with online reduction and tandem mass spectrometry detection

1-Nitropyrene (1-NP) is enriched in diesel exhaust particulate matter (DPM) relative to other sources of particulate matter (PM), and has been proposed as a marker for DPM. However, in ambient air, 1-NP concentrations are typically in the low pg/m(3) range. Therefore, collection of large volume air samples coupled with extensive sample clean-up procedures has been required to achieve adequate detection limits to measure 1-NP in ambient samples. We report here an improved LC-MS/MS method suitable for the detection and quantification of 1-NP in low volume ambient PM samples. The method involves ultrasonic extraction of ambient PM in organic solvent, concentration of the sample under reduced pressure, and two-dimensional HPLC analysis of the extract. 1-NP is isolated on the first HPLC column, then converted to 1-aminopyrene (1-AP) via online reduction in a column packed with a Pt/Rh catalyst. The 1-AP containing fraction from the first column is refocused on a trapping column, then eluted through a second HPLC column prior to MS/MS detection. Deuterated (d(9)) 1-NP (1-dNP) is added to each sample prior to extraction as an internal standard for quantification of 1-NP. The accuracy and precision of the assay, as applied to ambient particulate standard reference materials are 110+/-5.7% for SRM 1650b, 116+/-7.1% for SRM 2975, 108+/-5.8% for SRM 1649a, and 53+/-9.2% for SRM 1648. The analytical limit of detection was 152 fg on column, and analytical limit of quantitation 221 fg on column. To our knowledge, the sensitivity of this method is comparable with GC-NICI-MS methods while having the advantage of considerably less extensive sample preparation. This method is an approximately 10-fold improvement in sensitivity over HPLC methods utilizing fluorescence and/or chemiluminescence detection.

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

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

Determination of nitro-polycyclic aromatic hydrocarbons in atmospheric aerosols using HPLC fluorescence with a post-column derivatisation technique

The objective of this study was to develop an efficient and sensitive analytical protocol for the determination of nitrated polycyclic aromatic hydrocarbons (NPAHs) in aerosol samples. The separation of 16 NPAH (mono-and dinitro-PAH) was achieved by reversed-phase high-performance liquid chromatography (HPLC) followed by on-line reduction of the NPAHs to their corresponding amino polycyclic aromatic hydrocarbons (APAHs) and quantification by fluorescence detection. The main factors affecting the on-line reduction efficiency, such as the flow rate, the temperature, the position and packing of the reduction column were evaluated and optimised. The optimal conditions obtained were: packing of the reduction column with Pt-Al(2)O(3); a reduction column oven temperature of 90 degrees C; a flow rate of 0.8 mL min(-1). The resulting detection limits of the method ranged between 0.06 (2 NN) and 1.25 microg L(-1) (1.8 DNN), with an uncertainty of about 6%. The lifetime of the reduction column was identical to that of a typical analytical column. This analytical method was applied to particulate matter samples collected during December 2005 and August 2006 in Strasbourg (Alsace, eastern France). The NPAH concentrations observed for this urban site showed that the compounds are more abundant during winter (average of 534 pg m(-3)) than during summer (average of 118 pg m(-3)). 1-Nitropyrene was the predominant NPAH species, independent of season.

Optimization of an improved analytical method for the determination of 1-nitropyrene in milligram diesel soot samples by high-performance liquid chromatography–mass spectrometry

A method for determination of nitrated polycyclic aromatic hydrocarbons (NPAHs) in diesel soot by high-performance liquid chromatography-mass spectrometry with atmospheric pressure chemical ionization (APCI) and detection by ion-trap following ultrasonic extraction is described. The determination of 1-nitropyrene that it is the predominant NPAH in diesel soot was emphasized. Vaporization and drying temperatures of the APCI interface, electronic parameters of the MS detector and the analytical conditions in reversed-phase HPLC were optimized. The patterns of fragmentation of representative NPAHs were evaluated by single and multiple fragmentation steps and negative ionization led to the largest signals. The transition (247-->217) was employed for quantitative analysis of 1-nitropyrene. Calibration curves were linear between 1 and 15 microgL(-1) with correlation coefficients better than 0.999. Typical detection limit (DL) of 0.2 microgL(-1) was obtained. Samples of diesel soot and of the reference material (SRM-2975, NIST, USA) were extracted with methylene chloride. Recoveries were estimated by analysis of SRM 2975 and were between 82 and 105%. DL for 1-nitropyrene was better than 1.5 mg kg(-1), but the inclusion of an evaporation step in the sample processing procedure lowered the DL. The application of the method to diesel soot samples from bench motors showed levels <or=1 microg of 1-nitropyrene per gram of diesel soot.

Simple and sensitive method for determination of nitrated polycyclic aromatic hydrocarbons in diesel exhaust particles by gas chromatography-negative ion chemical ionisation tandem mass spectrometry

An extremely simple and sensitive method was developed for determination of nitrated polycyclic aromatic hydrocarbons (nitro-PAHs; mono-nitro-PAHs and dinitropyrenes) in diesel exhaust particles (DEPs) by gas chromatography-negative ion chemical ionisation tandem mass spectrometry (GC/NCI/MS/MS). We used two types of column in GC/NCI/MS/MS analysis. A polar column was used for determination of mono-nitro-PAHs, and a non-polar column was used for determination of dinitropyrenes and mono-nitro-PAHs except nitrofluoranthenes. The proposed method requires no clean-up procedure. The limits of detection ranged from 0.01 to 0.09 pg for all compounds tested. The applicability of the method to DEP samples was validated using diesel particulate standard reference materials (SRMs). Although DEPs contain complex matrices, all compounds could be detected easily in SRM2975 (diesel particulate matter) and SRM1975 (diesel particulate extract) without a clean-up procedure. The RSDs were less than 5% for all compounds examined. The quantitative results for SRMs exhibited good agreement with the available data in the literature. These results indicate that the proposed GC/NCI/MS/MS method is useful for determination of nitro-PAHs in DEP samples.

Biodirected mutagenic chemical assay of PM(10) extractable organic matter in Southwest Mexico City

The concentration of breathable particles (PM(10)) in urban areas has been associated with increases in morbidity and mortality of the exposed populations, therein the importance of this study. Organic compounds adsorbed to PM(10) are related to the increased risk to human health. Although some studies have shown the lack of correlation between specific mutagenic compounds in an organic complex mixture (OCM) and the mutagenic response in several bioassays, the same organic compounds selectively separated in less complex groups can show higher or lower mutagenic responses than in the OCM. In this study, we fractionated the OCM, from the PM(10) in four organic fractions of increasing polarity (F1-F4). The Salmonella bioassay with plate incorporation was applied for each one using TA98, with and without S9 (mammalian metabolic activation), and YG1021 (without S9) strains. The most polar fraction (F4) contained the greatest mass followed by F1 (non-polar), F2 and F3 (moderately polar). The concentrations of the OCM as well as the F4 were the only variables correlated with PM(10), atmospheric thermal inversions, fire-prone area, NO(2), SO(2), CO, rain and relative humidity. This indicated that polar organic compounds were originated in gas precursors formed during the atmospheric thermal inversions as well as the product of the incomplete combustion of vehicular exhausts and of burned vegetation. The percentages of the total PAH, and the individual PAH with molecular weight > or = 228 g mol(-1) (except retene) correlated with the percentages of indirect-acting mutagenicity in TA98+S9. The percentages of the total nitro-PAH and most of the analyzed individual nitro-PAH correlated with percentages of the direct-acting mutagenicity in both TA98-S9 and YG1021, the latter being more sensitive. In general, the highest mutagenic activity (indirect and direct) was found in F3 (moderately polar) and in F4 (polar). The non-polar fraction (F1) did not exhibit any kind of mutagenicity. In 77% of the cases, mutagenic activity was higher in the sum fractions with respect to their OCM. The combinations between F1, F2 and F4, with F3 under different or equal proportions suggested that mutagenicity reduction, in the combined matter of January (with TA98+S9 and YG1021) and of May (with YG1021), was due to concentrations of mutagens and non-mutagens in each fraction, and not to an antimutagenic effect. The organic compounds present in the non-polar fractions showed no antagonism, inhibition or reduction in the most mutagenic fractions in both indirect- and direct-acting mutagenicity, and the less polar organic compounds in F3 reduced mutagenicity in F4, in both months.

Effects of environmental air pollution on endogenous oxidative DNA damage in humans

Epidemiological studies conducted in metropolitan areas have demonstrated that exposure to environmental air pollution is associated with increases in mortality. Carcinogenic polycyclic aromatic hydrocarbons (c-PAHs) are the major source of genotoxic activities of organic mixtures associated with respirable particulate matter, which is a constituent of environmental air pollution. In this study,we wanted to evaluate the relationship between exposure to these genotoxic compounds present in the air and endogenous oxidative DNA damage in three different human populations exposed to varying levels of environmental air pollution. As measures of oxidative DNA damage we have determined 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and cyclic pyrimidopurinone N-1,N(2) malondialdehyde-2'-deoxyguanosine (M(1)dG) by the immunoslot blot assay from lymphocyte DNA of participating individuals. The level of endogenous oxidative DNA damage was significantly increased in individuals exposed to environmental air pollution compared to unexposed individuals from Kosice (8-oxodG adducts) and Sofia (M(1)dG adducts). However, there was no significant difference in the level of endogenous oxidative DNA and exposure to environmental air pollution in individuals from Prague (8-oxodG and M(1)dG adducts) and Kosice (M(1)dG adducts). The average level of M(1)dG adducts was significantly lower in unexposed and exposed individuals from Kosice compared to those from Prague and Sofia. The average level of 8-oxodG adducts was significantly higher in unexposed and exposed individuals from Kosice compared to those from Prague. A significant increasing trend according to the interaction of c-PAHs exposure and smoking status was observed in levels of 8-oxodG adducts in individuals from Kosice. However, no other relationship was observed for M(1)dG and 8-oxodG adduct levels with regard to the smoking status and c-PAH exposure status of the individuals. The conclusion that can be made from this study is that environmental air pollution may alter the endogenous oxidative DNA damage levels in humans but the effect appears to be related to the country where the individuals reside. Genetic polymorphisms of the genes involved in metabolism and detoxification and also differences in the DNA repair capacity and antioxidant status of the individuals could be possible explanations for the variation observed in the level of endogenous oxidative DNA damage for the different populations.

Analysis of nitro-polycyclic aromatic hydrocarbons in conventional diesel and Fischer-Tropsch diesel fuel emissions using electron monochromator-mass spectrometry

The presence of nitro-polycyclic aromatic hydrocarbons (NPAHs) in diesel fuel emissions has been studied for a number of years predominantly because of their contribution to the overall health and environmental risks associated with these emissions. Electron monochromator-mass spectrometry (EM-MS) is a highly selective and sensitive method for detection of NPAHs in complex matrixes, such as diesel emissions. Here, EM-MS was used to compare the levels of NPAHs in fuel emissions from conventional (petroleum) diesel, ultra-low sulfur/low-aromatic content diesel, Fischer-Tropsch synthetic diesel, and conventional diesel/synthetic diesel blend. The largest quantities of NPAHs were detected in the conventional diesel fuel emissions, while the ultra-low sulfur diesel and synthetic diesel fuel demonstrated a more than 50% reduction of NPAH quantities when compared to the conventional diesel fuel emissions. The emissions from the blend of conventional diesel with 30% synthetic diesel fuel also demonstrated a more than 30% reduction of the NPAH content when compared to the conventional diesel fuel emissions. In addition, a correlation was made between the aromatic content of the different fuel types and NPAH quantities and between the nitrogen oxides emissions from the different fuel types and NPAH quantities. The EM-MS system demonstrated high selectivity and sensitivity for detection of the NPAHs in the emissions with minimal sample cleanup required.

The mutagenic hazards of environmental PM2.5 in Turin

Owing to the large number of natural and anthropogenic sources, particulate matter (PM) may present several physical and chemical patterns in different areas. The finer PM2.5 fraction, which is now widely but not routinely measured in Europe, is considered to be the alveolar fraction of the ambient particles. Annual and winter mean concentrations of PM2.5 substantially vary in Europe, with higher concentrations in the South. The aims of this work were to (a) measure the PM2.5 levels in Turin over a long period, (b) evaluate mutagenic activities of organic extracts containing this collected complex mixture using the Ames test and (c) determine the level of polycyclic aromatic hydrocarbons (PAHs) in order to identify important mutagens in ambient air. Sampling was carried out from November 2001 to December 2004. The monthly mean of PM2.5 was 48.76+/-24.12 microg/m3. From the beginning to the end of the sample period there was a decrease in gravimetric levels, with annual means of 54.10+/-29.77 microg/m3 in 2002; 42.48+/-15.73 microg/m3 in 2003 and 45.89+/-24.92 microg/m3 in 2004. Samples were tested for mutagenicity using Salmonella typhimurium strains TA98 and TA100, with and without S9 mix metabolic activation. A positive genotoxic response was observed for TA98, with and without metabolic activation. The measured PAHs monthly mean level was 8.24+/-6.30 ng/m3, with values ranging from 0.20 to 21.38 ng/m3 Seasonal variation of gravimetric, mutagenic and PAH values was significant. The Salmonella assay results statistically correlated to PM2.5 and PAHs levels, but sometimes the mutagenic potencies were rather different despite an equal concentration of pollutant. The results confirm the usefulness of this biological approach to detect genotoxic properties of sampled PM2.5 and they show the variability of the mutagenic properties of the airborne mixture over time.

Genotoxicity of organic extracts of urban airborne particulate matter: an assessment within a personal exposure study

Airborne particulate matter, PM(10) and PM(2.5), are associated with a range of health effects including lung cancer. Their complex organic fraction contains genotoxic and carcinogenic compounds such as polycyclic aromatic hydrocarbons (PAHs) and their derivatives. This study evaluates the genotoxicity of the PM(10) and PM(2.5) organic extracts that were sampled in the framework of a personal exposure study in three French metropolitan areas (Paris, Rouen and Strasbourg), using the comet assay, performed on HeLa S3 cells. In each city, 60-90 non-smoking volunteers composed of two groups of equal size (adults and children) carried the personal Harvard Chempass multi-pollutant sampler during 48h along two different seasons ('hot' and 'cold'). Volunteers were selected so as to live (home and work/school) in 3 different urban sectors contrasted in terms of air pollution within each city (one highly exposed to traffic emissions, one influenced by local industrial sources, and a background urban environment). Genotoxic effects are stronger for PM(2.5) extracts than for PM(10), and greater in winter than in summer. Fine particles collected by subjects living within the traffic proximity sector present the strongest genotoxic responses, especially in the Paris metropolitan area. This work confirms the genotoxic potency of particulate matter (PM(10) and PM(2.5)) organic extracts to which urban populations are exposed.

Standard reference materials (SRMs) for determination of organic contaminants in environmental samples

For the past 25 years the National Institute of Standards and Technology (NIST) has developed certified reference materials (CRMs), known as standard reference materials (SRMs), for determination of organic contaminants in environmental matrices. Assignment of certified concentrations has usually been based on combining results from two or more independent analytical methods. The first-generation environmental-matrix SRMs were issued with certified concentrations for a limited number (5 to 10) of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). Improvements in the analytical certification approach significantly expanded the number and classes of contaminants determined. Environmental-matrix SRMs currently available include air and diesel particulate matter, coal tar, marine and river sediment, mussel tissue, fish oil and tissue, and human serum, with concentrations typically assigned for 50 to 90 organic contaminants, for example PAHs, nitro-substituted PAHs, PCBs, chlorinated pesticides, and polybrominated diphenyl ethers (PBDEs).

Effect of oxidation catalysts on diesel soot particles

The effect of a conventional oxidation catalyst and a novel particle oxidation catalyst (POC) on diesel particles is studied using identical methodology. Regulated particulate matter emission measurement is followed by analyzing soluble organic fraction. In addition, size distributions are measured using a partial flow sampling system with a thermodenuder as an option. A parallel ELPI-SMPS method is used to study the particle effective density and, further, the mass. Tests are conducted using a heavy duty diesel engine with a very low sulfur fuel. A decrease in particle mass was observed when using a catalyst. When using a conventional catalyst the decrease was attributed to the decrease of soluble organic fraction, while using POC the nonsoluble fraction was also found to decrease, by 8-38%. This observation is confirmed by particle number measurement, and POC was found to decrease the dry particle number concentration measured downstream of a thermodenuder by 13-28%. Further particle structure analysis indicated lower density values when using conventional catalyst or POC. The physical size of the particles was not changed noticeably over either catalyst--implying the soluble organic fraction was condensed onto the soot, filling the voids in the porous structure of soot agglomerates, when no catalyst is used.

Simultaneous analysis of oxygenated and nitrated polycyclic aromatic hydrocarbons on standard reference material 1649a (urban dust) and on natural ambient air samples by gas chromatography–mass spectrometry with negative ion chemical ionisation

This study deals with the development of a routine analytical method using gas chromatography-mass spectrometry with negative ion chemical ionisation (GC/NICI-MS) for the determination of 17 nitrated polycyclic aromatic hydrocarbons (NPAHs) and 9 oxygenated polycyclic aromatic hydrocarbons (OPAHs) present at low concentrations in the atmosphere. This method includes a liquid chromatography purification procedure on solid-phase extraction (SPE) cartridge. Application of this analytical procedure has been performed on standard reference material (SRM 1649a: urban dust), giving results in good agreement with the few data available in the literature. The analytical method was also applied on ambient air samples (on both gas and particulate phases) from the French POVA program (POllution des Vallées Alpines). NPAHs concentrations observed for a rural site during the Winter period are about 0.2-100.0pgm(-3) in the particulate phase and about 0.0-20.0pgm(-3) in the gas phase. OPAHs present concentrations 10-100 times higher (0.1-2.0ngm(-3) and 0.0-1.4ngm(-3) for the particulate and the gas phases, respectively). These preliminary results show a good correlation between the characteristics of the sampling site and the compound origins (primary or secondary).

Analysis of nitrated polycyclic aromatic hydrocarbons

Many nitrated polycyclic aromatic hydrocarbons (NPAH) that are present in low concentrations in the environment and in emission sources have been shown to be mutagenic and/or carcinogenic. This paper reviews the current methods of analysis of these compounds with the emphasis on NPAH measurements in ambient particulate matter samples.

Diesel exhaust particles enhance T-cell activation in severe asthmatics

Prevalence of asthma is increasing in westernized countries. Epidemiological studies showed the impact of traffic pollution on the triggering of asthma symptoms and exacerbations, and this effect is mainly attributed to the polycyclic aromatic hydrocarbon core of diesel exhaust particles (DEP). However, although DEP induce IgE synthesis, little is known of their role on T-cell activation, the main cells orchestrating asthma inflammation. We assessed the effect of DEP on T-cell activation in severe uncontrolled asthmatics during (n = 13) and outside (n = 19) exacerbations. Results were compared with data obtained in healthy controls (n = 14). Peripheral blood mononuclear cells were cultured in the presence of low-dose DEP. T-cell activation markers, CD69 and CD25, interleukin-4 (IL-4) and interferon (IFN)-gamma production and T-cell proliferation were assessed by flow cytometry. DEP exposure increased the proportion of CD3+CD69+ T cells in all subjects. The proportion of CD25+ T cells increased under DEP stimulation in the exacerbation group only. IFN-gamma- and IL-4-producing T cells increased in both asthmatic groups, especially during exacerbations, but not in controls. This effect was more pronounced for IL-4. In response to DEP stimulation, T-cell proliferation increased in higher proportion in asthmatics compared with controls. These results show that DEP activate T cells in asthmatics only, with a higher effect during exacerbations. This is in keeping with epidemiological data which demonstrated that DEP trigger respiratory symptoms in asthmatics but not in controls. The higher effect of DEP in exacerbated asthmatics suggests that uncontrolled asthma is a risk factor for aggravation under exposure to traffic pollutants.

Identification of mammalian cell genotoxins in respirable diesel exhaust particles by bioassay-directed chemical analysis

A bioassay-directed chemical analysis which consists of mammalian cell bioassays (comet assay, CBMN assay and EROD-microbioassay) in conjunction with analytical measurements was performed to identify the most biologically active compounds of the diesel exhaust particulate matters (DEPs) on mutagenic activity. These bioassay systems were suitable to estimate the mammalian genotoxic potentials of pollutants present in low concentrations in limited environmental samples, as is the case with DEPEs. The results from mutagenic assay showed that the aromatic and slightly polar fraction of DEPs induced chromosomal damage and DNA breakage in a non-cytotoxic dose. It was also revealed that indirect-acting mutagens may mainly contribute to the mutagenic effect of aromatic fraction via the enzyme metabolism system. In the aromatic fraction, several indirect-acting mutagenic PAHs such as dibenzo(a,h)anthracene, chrysene, and 1,2-benzanthracene were detected by GC-MS and the complex mixture effect of this fraction was quantified in terms of its biological-TCDD equivalent concentration (bio-TEQ) which was 32.82 bio-TEQ ng/g-DEPs by EROD-microbioassay. Conclusively, we confirmed that indirect-acting mutagens contained in aromatic fraction may be important causatives of the genotoxicity of extracts of DEPs by integrating the results obtained from a mammalian cell bioassay-directed fractionation.